JPH07252859A - Bulldozer earthwork plate device and control method thereof - Google Patents

Abstract

(57) [Summary] [Purpose] To enable bulldozers to carry large amounts of soil on vehicles with a relatively small vehicle weight and engine output. [Structure] The tangent line 14 at the lower end of the curve of the front plate 11 is tilted backward by an angle γ with respect to the surface 13 of the cutting edge 12 attached to the lower end portion of the front plate 11 of the earthwork plate 10 to make the earthwork plate 10 at an angle θ.
Tilt backward by 1. Therefore, the amount of soil loaded on the earthworking board 10 increases, the apparent vehicle weight increases, and the traction force increases. In addition, the amount of soil deposited in front of the earthwork plate will decrease and the soil resistance will decrease, but the overall amount of soil will increase. Therefore, even a vehicle having a relatively small vehicle weight and a small engine output can carry a large amount of soil, and the soil discharging property is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an earthwork plate apparatus and a control method thereof for a bulldozer capable of vertically moving, tilting and pitching the earthwork plate.

[0002]

2. Description of the Related Art FIG. 16 is a side view of a bulldozer 1 provided with a conventional earthwork plate.
A and 3B are swingably mounted, and an earthworking plate 50 is swingably mounted in the front-rear direction at the tips of the frames 3A and 3B. The left and right ends of the earthwork plate 50 and the frames 3A and 3B are connected by pitch cylinders 4A and 4B, and the vehicle body 2 and the earthwork plate 50 are connected by lift cylinders 5A and 5B. A front plate 51 of the earthwork plate 50 is formed by a concave curved surface, and a cutting edge 52 is attached to the lower end of the curved surface in a substantially tangential direction. By expanding and contracting the lift cylinder 5, the earthworking plate 50 moves up and down as indicated by arrow A, and by expanding and contracting the pitch cylinders 4A and 4B at the same time, the earthworking plate 50 pitches forward and backward as indicated by arrow B to move the pitch cylinder 4A. 4B by expanding or contracting only one of them, or by extending one and shortening the other, FIG.
As shown by the two-dot chain line in the front view of the bulldozer 1 shown in
The earthwork plate 50 is tilted.

Conventionally, in a bulldozer, for example, as proposed in Japanese Utility Model Laid-Open No. 3-50646, a single operation lever and a single tilt or pitch switching switch are used to raise, lower, tilt and pitch the earthwork plate. It is designed to operate. The edge angle (α) of the earthwork plate at the time of ground contact is usually about 55 ° under normal soil conditions and working conditions, but the blade angle can be adjusted to ± 5 ° depending on the soil properties and working conditions.

The balance of forces in the earthmoving work of the bulldozer must be such that the traction force F2 is larger than the earth conveyance resistance F1 shown in FIG. 18 and the vehicle driving force F3 is larger than the traction force F2. That is, if the weight of the soil 6 is G, the coefficient of friction with the ground is μ1, the weight of the bulldozer 1 is W, the coefficient of friction with the ground is μ2, the engine torque is T0, the reduction ratio is ρ, and the drive wheel radius is R, then F1 = G × μ1 <F2 = W × μ2 <F3 = T0 × ρ / R, and in the case of increasing the work load of the bulldozer, the size of the bulldozer has conventionally been increased, the engine output increased, and the earthwork plate capacity increased. Has been achieved by increasing. In other words, if you want to double the amount of earthwork,
This has been achieved by making the engine output almost double and the vehicle weight almost double, and the series of bulldozers is being pursued based on the above idea.

Further, the hydraulic pump capacity for driving the working machine of the bulldozer is usually set by the required amount of the earthwork plate lifting lift cylinder.

[0006]

However, in the case of manufacturing a bulldozer capable of performing an earthwork amount which is twice as large as the largest class in the series, in a similar type bulldozer, the stress applied to each frame of the vehicle body and the life of the driving device are reduced. In order to keep the value within the allowable value, technical problems such as vehicle weight and material must be solved. If these technical problems are solved, there is a problem that the manufacturing cost of the bulldozer increases more than linearly proportional to the earthwork amount. Regarding this technical problem, the applicant of the SAE Paper No. 79090
It is announced in 2. Therefore, even though there is a demand for large-volume bulldozers, it is difficult to meet the demand due to technical and economic difficulties.

The present invention has been made by paying attention to the above-mentioned problems, and it is possible to greatly increase the amount of soil transported without significantly increasing the engine output and the vehicle weight. It is an object of the present invention to provide an earthwork board device for a bulldozer and a method for controlling the earthwork plate device.

[0008]

In order to achieve the above object, a method for controlling an earthwork plate of a bulldozer according to the present invention is shown in FIG.
As shown in FIG. 5, the earthworking plate 10 is swingably mounted in the front-rear direction at the ends of the frames 3A and 3B that are swingably mounted on both sides of the vehicle body. When tilting the soil, it tilts backward (pitch back) by a predetermined angle to increase the amount of soil, and at the time of soil discharging, tilts forward (pitch dump) by a predetermined angle to facilitate soil removal. It is designed to be controlled to do so.

In the above structure, the earthwork plate 10 is tilted backward (pitch back) from the excavated state to 20 ° during soil loading, and is tilted forward (pitch dump) from the excavated state to 45 ° during soil discharging. 10 is controlled.

In this case, the edge angle of the earthworking plate 10 is tilted backward (pitch back) to 35 ° when carrying soil, and 1 when carrying out soiling.
Earthwork plate 10 to tilt forward (pitch dump) to 00 °
Will be controlled.

Further, as shown in FIG. 7, a tilt / pitch switching means 24 for controlling the earthwork plate 10 to tilt forward or backward.
And a combination of the pitch speed switching means 25 and the operation means 22 used for raising and lowering the earthworking plate, excavation posture (lift + tilt), soil carrying posture (lift + pitchback), earth discharging posture (lift + pitch dump). The earthwork plate 10 is controlled so as to select any one of the above.

A first bulldozer earthmoving plate device according to the present invention comprises a frame 3A, which is swingably mounted on both sides of a vehicle body.
The earthworking board 10 is attached to the tip of 3B so as to be swingable in the front-rear direction, and the left and right ends of the earthworking board 10 and the frame 3A,
3B and cylinders 4A and 4B, respectively,
An earthworking plate device of a bulldozer, which allows the earthworking plate 10 to be tilted left and right and tilted forward or backward by expanding and contracting the cylinders 4A and 4B.
The tilt-back angle is 5 with respect to the posture when excavating
It is possible to set the angle between 0 ° and 20 °. In this case, the rearward tilt (pitch back) angle is determined by the lift cylinders 5A, 5A.
It is set by the limit of the lifting force of B and the limit of the strength of the lower part of the earthwork plate.

In the above structure, the forward inclination (pitch dump) angle is 5 ° or more with respect to the posture of the earthwork plate 10 during excavation.
It can be set below °. The forward inclination (pitch dump) angle in this case is set in consideration of the repose angle of the excavated soil so that the soil can be discharged on the uphill where the excavation work of the bulldozer can be performed.

Further, the drive hydraulic system for the earthwork plate 10 is
For example, as shown in FIG. 9, a hydraulic pump 30 that is a hydraulic source.
A, 30B, switching operation means 24 for switching between tilt operation and pitch operation, and directional control valves 20A, 20B for controlling pressure oil to the cylinders 4A, 4B.

In the above structure, the hydraulic pressure source is composed of the main hydraulic pumps 30A and 30B and the support hydraulic pump 31, and the support hydraulic pump 31 discharges the main hydraulic pumps 30A and 30B via the electromagnetic switching valve 32. The electromagnetic switching valve 32 is connected to a pipeline and constitutes a support circuit controlled by an external signal.

Further, the pitch control means for the earthworking plate 10 comprises an operation means 22 for the earthworking plate 10, a tilt / pitch switching means 24, and a pitch speed switching means 25.

As shown in FIG. 10, the earthmoving plate device for the second bulldozer according to the present invention is different from the earthmoving plate device for the first bulldozer according to the present invention in that the hydraulic pressure source of the drive hydraulic device for the earthwork plate 10 is of a variable capacity. Type hydraulic pumps 21A and 21B, the variable displacement hydraulic pumps 21A and 21B are controlled by an external signal.

As shown in FIG. 11, the earthmoving plate device for a third bulldozer of the present invention is different from the earthmoving plate device for a first bulldozer of the present invention in that the drive hydraulic device for the earthwork plate 10 is one.
The fixed-capacity hydraulic pump 30A is used as the hydraulic pump 3.
The pressure oil from 0A is connected to the bottom side conduit of the first cylinder 4A, and the head side conduit of the first cylinder 4A and the second cylinder 4A are connected to the bottom side conduit.
The only difference is the configuration in which the bottom side pipeline of the cylinder 4B is connected via the electromagnetic switching valve 42, and the head side pipeline of the second cylinder 4B is connected to the drain pipeline via the electromagnetic switching valve 41.

A fourth bulldozer earthmoving plate device of the present invention is, as shown in FIG. 1, a cutting edge mounted on the lower end portion of the front face of the earthworking plate 10 in the first to third bulldozer earthmoving plate devices. The angle γ of the lower end of the concave portion of the front plate of the earthwork plate 10 is inclined rearward with respect to the surface 12 of the earthwork plate 10.

In the above construction, the angle γ at which the lower end of the recess of the front plate of the earthwork plate 10 is tilted backward with respect to the surface of the cutting edge 12 is set to an optimum value of 15 ° or less.

The earthmoving board device of the fifth bulldozer of the present invention is, as shown in FIG. 14, the earthworking board 10 which is swingable in the front-rear direction at the tips of the frames 3A and 3B mounted on both sides of the vehicle body.
And the left and right ends of the earthwork plate 10 and the frames 3A and 3B are connected by cylinders 4A and 4B, respectively, and the cylinders 4A and 4B are expanded and contracted to tilt the earthwork plate 10 left and right, and A bulldozer earthmoving plate device capable of tilting forward or backward, wherein the cylinder comprises a first cylinder 4A and a second cylinder 4B, and the connecting position of the first cylinder 4A and the second cylinder 4B. The connecting position is asymmetric.

In the above structure, the first cylinder 4A
And the rod length of the second cylinder 4B are the same.

Further, the first cylinder 4A and the second cylinder 4B may be different in minimum rod length and / or stroke.

The earthmoving board device of the sixth bulldozer of the present invention is, as shown in FIGS. 7 and 12, an operating means 22 for the earthworking board 10, pitch dump switching means 25, 25A and pitch back switching means 24, 24A. Is provided.

In the above structure, the pitch dump switching means 25, 25A or the pitch back switching means 24, 24
A controller 47 that receives a signal from A transmits a command signal to the pitch dump control valve 44A or the pitch back control valve 44B and the electromagnetic switching valve 45, and opens the supporting solenoid valves 43A and 43B from the command signal from the controller 47. The support circuit is configured to control the position to join the discharge flow rates from the support hydraulic pumps 31A and 31B to the discharge pipelines of the main hydraulic pumps 30A and 30B.

[0026]

According to the above structure, as shown in FIG. 6, the earthwork plate of the bulldozer is tilted backward by a predetermined angle when carrying soil with respect to the posture during excavation, so that the amount of earth loaded on the earthwork plate increases. At the same time, the force that tries to dig the earthwork plate into the ground works. For this reason, the operator will carry the soil while performing an operation to lift the earthwork plate, and a force that pushes the ground to the ground will be generated at the front part of the body of the bulldozer, and the ground pressure distribution of the track of the vehicle will be By comparison, it becomes more uniform and the apparent vehicle weight increases and the traction force increases. Further, the weight of the soil accumulated in front of the cutting edge of the earthwork plate and the ground contact length of the soil on the ground are reduced by the amount of the soil loaded on the earthwork plate (from L1 to L2), and the earth pushing resistance is reduced. Therefore, compared to the configuration of the conventional bulldozer, a large amount of soil can be transported even in a vehicle with a light weight. Next, when excavating the soil, the soil scavenging property is improved by tilting it forward much more than before. In this case, the inclination angle of the earthwork plate is set in consideration of the repose angle of the excavated soil so that the excavation work of the bulldozer enables the soil to be discharged at a climbing slope.

Next, in order to perform the above-mentioned work, it is possible to select three work postures of (1) excavation posture, (2) soil carrying posture, and (3) soil discharging posture, and earthworking plate operating means, Tilt / pitch switching operation means and pitch speed switching operation means are provided, and the operator can easily select the work posture during operation by combining them. That is, when only the earthwork plate operation means is operated, the excavation posture is selected by raising and lowering the earthwork board (1), and when the tilt / pitch switching operation means is turned on from the above operation state (2) Soil movement When the attitude is selected and the pitch speed switching operation means is turned on, (3) the earth unloading attitude can be selected, and the bulldozer excavation / earthing / earth unloading work can be easily performed.

Further, by using the switching operation means for exclusive use of the pitch dump and the switching operation means for exclusive use of the pitch back, it is possible to swiftly select and switch the excavation / earthing / earthing work of the bulldozer.

Further, as shown in FIG. 9, the earthmoving plate driving hydraulic device of the earthmoving plate device of the first bulldozer according to the present invention is provided with a main hydraulic pump and a supporting hydraulic pump, and the discharge circuit of the main hydraulic pump is provided. And a support solenoid valve that controls the connection and disconnection with the discharge circuit of the support hydraulic pump, and it is possible to control the support solenoid valve by an external signal. During operation, release the cheering to reduce the amount of discharge to the cylinder to reduce power loss, and when the soil is being discharged, control the solenoid valve for cheering with an external signal to control the amount of discharge to the cylinder by the hydraulic pump for cheering. As a result, the pitch operation time can be shortened even with a large pitch dump angle or a large pitch back angle of the earthwork plate.

Further, as shown in FIG. 10, the drive hydraulic system for the earthmoving plate of the earthmoving plate apparatus of the second bulldozer of the present invention is provided with a variable displacement hydraulic pump as a hydraulic pressure source, and the discharge of this variable displacement hydraulic pump. Since the amount can be controlled by an external signal, the discharge amount is reduced during normal tilting operation or pitching operation in the excavation posture or soil transportation posture to reduce power loss, and when the soil discharging posture is increased by the external signal. However, the pitch operation time can be shortened even with a large pitch dump angle or a large pitch back angle of the earthwork plate.

Further, as shown in FIG. 11, the earthmoving plate driving hydraulic device of the earthmoving plate device of the third bulldozer according to the present invention transfers the pressure oil from the hydraulic pump to the first cylinder 4 through the direction control valve.
It is connected to the bottom side conduit of A and is connected to the first cylinder 4A.
The head side pipe line of the second cylinder 4B is connected to the bottom side pipe line of the second cylinder 4B via an electromagnetic switching valve, and the head side pipe line of the second cylinder 4B is connected to a drain circuit via the electromagnetic switching valve. Since it is a circuit, the first cylinder 4A and the second cylinder 4B are in parallel during the normal tilting operation or pitching operation in the excavation posture or the soil conveyance posture, and the pressure oil from the hydraulic pump is divided into halves. Cylinder 4
A and the second cylinder 4B. Next, when the earth unloading posture is used, the external signal is turned on to control the electromagnetic switching valve, and the pressure oil from the hydraulic pump is transferred between the first cylinder 4A and the second cylinder 4B via the direction control valve and the electromagnetic switching valve. Since it is connected in series, the total amount is from the first cylinder 4A to the second cylinder.
It is possible to reduce the pitch operation time even if the earthwork plate has a large pitch dump angle or a large pitch back angle by flowing into the cylinder 4B in the series.

Next, as shown in FIG. 1, the lower end of the concave surface of the earthwork plate front plate is tilted backward by an angle γ with respect to the surface of the cutting edge of the earthwork plate to make the earthwork plate larger than the pitch back angle during soil loading. Since the front surface of the soil can be tilted rearward, the load of soil on the earthwork plate increases and it is possible to prevent the excavated soil from being consolidated by the concave surface when flowing along the front plate. The soil removal at the time of soil removal is improved and the soil removal performance is improved.

Further, as shown in FIG. 14, when the back surface of the earthwork plate is perpendicular to the ground, the rod of the first cylinder 4A is shortened in advance, while the second cylinder 4A is shortened.
Since the rod B is pre-extended, the two cylinders have different minimum strokes when the earthwork plate is pitched back, and by further shortening one cylinder, the earthwork plate can be tilted. Therefore, the tilt operation can be performed in the soil carrying attitude.

[0034]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a bulldozer earthwork plate device according to the present invention will be described below in detail with reference to the drawings. Figure 1
FIG. 3 is a side view of the earthwork plate 10, in which a cutting edge 12 is attached to a lower end portion of a front plate 11 formed of a concave curved surface, and a lower end of a curved line of the front plate 11 with respect to a surface 13 of the cutting edge 12. The tangent line 14 of is tilted backward by an angle γ. In the present embodiment, γ = 10 °, but this angle γ is 15 ° due to the soil and the like.
It is set to the following optimum value. This angle γ
Is more than 15 °, there is a problem that spillage to the rear of the earthwork plate during excavation work increases, so it is set to 15 ° or less. In FIG. 1, the thick solid line indicates a general excavation posture, in which the blade edge angle α is 55 °, and the front plate recess lower end-to-ground angle β is 45 °. The chain double-dashed line indicates the soil carrying attitude, and the backward tilt (pitch back) angle θ1 at this time is 10 ° in this embodiment, but this angle θ1 is set to the optimum angle in the range of 5 ° to 20 ° depending on the soil quality and the like. It is set.
In this case, the backward tilt (pitch back) angle is set by the limit of the lifting force of the lift cylinder and the limit of the strength of the lower part of the earthwork plate.

The thin solid line in FIG. 1 indicates the earth unloading posture, and the forward inclination (pitch dump) angle θ2 at this time is set to 30 ° in this embodiment in accordance with general soil properties and working conditions. However, this angle θ2 is set to an optimum angle in the range of 5 ° to 45 ° depending on the soil quality or the like. This earthmoving plate forward inclination (pitch dump) angle θ2 is set to 45 ° at the maximum because it is soil such as clayey soil, so that it is possible to remove soil even under the worst working conditions on the uphill where excavation work of the bulldozer is possible. It is set in consideration of the angle of repose of excavated soil. Because it is like this,
Depending on the working conditions, the operator can freely operate the earthmoving plate forward tilt (pitch dump).

Next, a method of operating the earthwork plate 10 from excavation to soil transportation and soil discharging will be described. As mentioned above when drilling,
As shown in FIG. 2, work is performed with the cutting edge angle α of the earthwork plate 10 = 55 ° and the front plate / ground angle β = 45 °. At the time of soil transportation, as shown in FIG. 3, the first cylinder 4A and the second cylinder 4B are shortened to make the earthwork plate 10 pitch back by 10 °, and the cutting edge angle α1
= 45 °, front plate to ground angle β1 = 35 °. FIG. 6 shows a comparison between the earthmoving board 50 in the conventional soil carrying attitude and the earthworking board 10 in the soil carrying attitude according to the present invention, which is indicated by a dashed line. The earthmoving plate 50 in the conventional soil carrying attitude is operated by pushing down the earthworking plate 50 and carrying the soil, so that the front of the vehicle body is lifted and the traction force commensurate with the weight of the vehicle body cannot be obtained. Since the earthwork plate 10 is tilted backward by a predetermined angle when carrying soil with respect to the posture at the time of excavation, the amount of soil loaded on the earthwork plate is increased by the amount of soil in the cross-hatched portion and the earthwork plate is grounded. Since the force that tries to bite is applied, the operator carries the soil while performing the operation to lift the earthwork plate, which causes the force that pushes the front part of the car body of the bulldozer against the ground, The ground contact pressure distribution of the crawler belt becomes almost uniform, the apparent vehicle weight increases, and the traction force increases. Further, as shown in FIG. 6, the ground contact length of the accumulated soil on the front surface of the earth moving plate 50 in the conventional soil carrying attitude is L2, whereas the ground contact length of the accumulated soil on the front surface of the earth moving plate 10 in the soil carrying attitude of the present invention is 18, the weight G shown in FIG. 18 is reduced, and the soil resistance F1 is reduced. Therefore, compared with the configuration of the conventional bulldozer, according to the present invention, even a vehicle having a relatively light vehicle weight and a relatively small engine output can achieve the same amount of soil as a large vehicle.

Next, at the time of earth removal, as shown in FIG.
The cylinder 4A and the second cylinder 4B are extended to extend the earthwork plate 10.
Is dumped by 30 ° (θ2) and the cutting edge angle α2 = 85
And the front plate to ground angle β2 = 75 °. At this time, in order to completely discharge the soil forward, the vehicle moves forward while pitch dumping the earthworking plate 10 and at the same time the lift cylinder 5
Shorten A and 5B and lift. Figure 5 shows the earthwork plate 10.
30 degree pitch dump, lift cylinders 5A, 5B
Shows a state in which the blade is maximally lifted with the blade edge angle α3 = 73 ° and the front plate-to-ground angle β3 = 63 °, and the soil is completely discharged. Even on an uphill of 20 °, the cutting edge angle α = 53 ° and the front plate to ground angle β = 43 °, so that in a general soil condition, sufficient soil removal performance can be secured even on an uphill slope. In addition, in order to ensure sufficient soil removal properties even on soils such as clayey soils and on uphill slopes, the earthwork plate forward inclination (pitch dump) angle θ2 is set to 45.
It should be, and it is possible.

FIG. 7 is a perspective view of the operation lever 22. The knob 23 of the operation lever 22 is provided with a tilt / pitch changeover switch 24 and a pitch speed changeover switch 25 for changing the tilt operation, which is a signal transmitting means, to the pitch operation. Has been.

FIG. 8 is a diagram showing the relationship between the operating position of the operation lever 22 and the operation of the earthwork plate. When the tilt / pitch changeover switch 24 is off, the operation lever 22 is tilted to the right, and the earthwork plate is tilted to the right. Then, when tilted to the left, the earthwork plate tilts to the left, when tilted backward, the earthwork plate rises, and when tilted forward, it descends.

When the tilt / pitch selector switch 24 is turned on and the operation lever 22 is tilted to the right, the earthwork plate is pitch dumped, and when tilted to the left, pitch back is performed.

Further, when the pitch speed changeover switch 25 is turned on and the operating lever 22 is tilted to the right, the earthwork plate is dumped at a high speed, and when it is tilted to the left, a high speed pitch back is performed.

As described above, when the tilt / pitch changeover switch 24 is turned on and the operation lever 22 is tilted diagonally to the left front, the earthwork plate descends while pitching back to the soil carrying posture.

When the pitch speed changeover switch 25 is turned on and the operation lever 22 is tilted obliquely rearward to the right, the earthwork plate is raised at a high speed by a pitch dump to be in the earth discharging posture.

As described above, the earthwork plate 1 according to this embodiment.
The pitch angle from the maximum pitch back of 0 to the maximum pitch dump is 40 °. The pitch range of the conventional earthwork plate is ± 5 °, that is, 10 ° as described above.
The pitch range of this embodiment is greatly increased over that of the conventional one. Therefore, there arises a problem that the cycle time becomes long when the earthmoving plate is moved back to the maximum stroke pitch and moved to the earth discharging position by dumping the maximum stroke pitch. In order to solve the above problems, the present invention proposes the following drive hydraulic device.

FIG. 9 is a hydraulic circuit diagram of the earthmoving board device for the first bulldozer according to the present invention. It should be noted that this circuit diagram shows a pitch operation circuit, and the lift operation circuit is the same as the conventional one and is omitted. The first cylinder 4A and the second cylinder 4 via the first directional control valve 20A and the second directional control valve 20B.
Hydraulic pumps 30A and 30B connected to B are fixed displacement hydraulic pumps, and 31 is a support hydraulic pump. The discharge circuit of the support hydraulic pump 31 is connected to the discharge circuits of the hydraulic pumps 30A and 30B via the support solenoid valve 32, and the pitch speed changeover switch 25 is connected to the support solenoid valve 32. Open and close.
When the support solenoid valve 32 is in the closed position (b), the pressure oil discharged from the support hydraulic pump 31 is drained to the tank. The pilot pressure control valve 26 of the operating lever 22 is connected to the first directional control valve 20A, and the second directional control valve 2
0B is connected via an electromagnetic switching valve 35. The electromagnetic switching valve 35 is connected to the tilt / pitch switching switch 24 and the pitch speed switching switch 25 provided on the operation lever 22.

Next, the operation will be described. When the operating lever 22 is operated in the left-right direction, the first directional control valve 20A operates to extend / contract the first cylinder 4A and tilt the earthwork plate 10 left / right. When the tilt / pitch changeover switch 24 of the operation lever 22 is turned on, the electromagnetic changeover valve 35 is switched to the A position, and when the operation lever 22 is operated left and right, the first directional control valve 20A and the second directional control valve 20B are activated. As a result, the first cylinder 4A and the second cylinder 4B simultaneously operate in the same direction, and the earthwork plate 10 pitches back (tilts backward) or dumps (tilts forward). When the pitch speed changeover switch 25 provided on the operation lever 22 is turned on, the electromagnetic changeover valve 35 is set to the A position, and the support solenoid valve 32 is switched to the open position (a), and the support hydraulic pump 3
The first discharge conduit merges with the discharge conduits of the hydraulic pumps 30A and 30B, the discharge amount increases, and the earthwork plate 10 pitches back (backwardly tilts) or pitches (forwardly tilts) at high speed.
In this embodiment, the description has been given with the combination of the two main hydraulic pumps and the support hydraulic pump, but the discharge flow rates of one main hydraulic pump and the support hydraulic pump are supplied to the first cylinder 4A and the second cylinder 4B to set the pitch. It is also possible to form a circuit that joins the discharge flow rates of the supporting hydraulic pump when the back (backward tilt) or the pitch dump (forward tilt) is performed quickly.

The tilt / pitch selector switch 24 is turned on.
When N is set and the operation lever 22 is tilted diagonally forward left, the earthwork plate descends while pitching back to the soil carrying position. When the pitch speed changeover switch 25 is turned ON and the operation lever 22 is tilted diagonally right rearward, the earthwork plate moves at high speed. Then, the pitch is dumped while climbing, and the soil is discharged.

FIG. 10 is a hydraulic circuit diagram of the earthwork plate device for the second bulldozer according to the present invention. It should be noted that this circuit diagram shows a pitch operation circuit, and the lift operation circuit is the same as the conventional one and is omitted. The first cylinder 4A is connected to the variable displacement hydraulic pump 21A via the first directional control valve 20A, and the second cylinder 4B is connected to the variable displacement hydraulic pump 21B via the second directional control valve 20B. is doing. Two
Reference numeral 2 is an operating lever, 26 is a pressure control valve for controlling pilot hydraulic pressure, and 27 is a hydraulic pump for pilot hydraulic pressure.
The operation lever 22 is provided with a pitch speed changeover switch 25, and the variable displacement hydraulic pumps 21A and 21B are provided.
And the electromagnetic switching valve 28. Pressure control valve 26
Is connected to the first directional control valve 20A, and is connected to the second directional control valve 20B via an electromagnetic switching valve 28. The electromagnetic switching valve 28 is connected to the tilt / pitch switching switch 24 provided on the operation lever 22.

Next, the operation will be described. In FIG. 10, when the operation lever 22 is operated in the left / right direction, the first directional control valve 20A operates to extend / contract the first cylinder 4A and tilt the earthwork plate 10 left / right. Operating lever 22
When the tilt / pitch changeover switch 24 is turned on, the electromagnetic changeover valve 28 is switched to the A position, and when the operation lever 22 is operated to the left or right, the first directional control valve 20A and the second directional control valve 20B are activated and the first directional control valve 20B is operated. The cylinder 4A and the second cylinder 4B simultaneously operate in the same direction, and the earthwork plate 10 pitches back (tilts backward) or pitches (tilts forward).
Further, when the pitch speed changeover switch 25 is turned ON and the operation lever 22 is operated to the left or right, the discharge amounts of the variable displacement hydraulic pumps 21A and 21B are increased, and the earthwork plate 10 is pitched back (reclined) or pitch dumped (rearward). Since it tilts forward, it is possible to shorten the pitch operation time of the earthwork plate 10. In this embodiment, two variable displacement hydraulic pumps have been described, but one variable displacement hydraulic pump is also possible.

The tilt / pitch selector switch 24 is turned on.
When N is set and the operation lever 22 is tilted diagonally forward left, the earthwork plate descends while pitching back to the soil carrying position. When the pitch speed changeover switch 25 is turned ON and the operation lever 22 is tilted diagonally right rearward, the earthwork plate moves at high speed. Then, the pitch is dumped while climbing, and the soil is discharged.

FIG. 11 is a hydraulic circuit diagram of an earthwork plate device for a third bulldozer according to the present invention. Incidentally, this circuit diagram shows the pitch operation circuit, and the lift operation circuit is the same as the conventional one and is omitted. The first, second, and third electromagnetic switching valves 40, 41, 42 are provided on the circuit connecting the first directional control valve 20A and the second directional control valve 20B and the first cylinder 4A and the second cylinder 4B. The electromagnetic switching valves 40, 41, 42 shown in FIG. 11 are in an OFF state. At this time, the pressure oil discharged from the hydraulic pumps 30A, 30B is the first directional control valve 20A and The operation lever 22 is adapted to be supplied to the first cylinder 4A and the second cylinder 4B via the second directional control valve 20B.
When is operated in the left-right direction, the first directional control valve 20A operates to expand and contract the first cylinder 4A, and the earthwork plate 10 can be tilted left and right.

Next, the operation will be described. In FIG. 11, the tilt / pitch changeover switch 2 of the operation lever 22
When 4 is turned on, the electromagnetic switching valve 35 is switched to the A position, and when the operating lever 22 is operated in the left-right direction, the first directional control valve 20A and the second directional control valve 20B operate to operate the first cylinder 4A and the second cylinder 4A. The cylinders 4B simultaneously operate in the same direction, and the earthwork plate 10 pitches back or dumps.

Next, when the pitch speed changeover switch 25 of the operation lever 22 is turned on, the first, second and third electromagnetic changeover valves 40, 41 and 42 are simultaneously changed over to form the next circuit. When the first electromagnetic switching valve 40 is turned on, the pressure oil discharged from the second hydraulic pump 30B becomes the second directional control valve 20.
From the discharge line of B through the first electromagnetic switching valve 40, the second
The pressure oil discharged from the hydraulic pump 30A merges with the discharge pipe line on the downstream side of the first directional control valve 20A, and the first cylinder 4A
Flows into the bottom chamber of. On the other hand, the second electromagnetic switching valve 41 is also turned on.
It is operating and the pressure oil is drained to the tank from the head side pipe line of the second cylinder 4B via the second electromagnetic switching valve 41. And the other third electromagnetic switching valve 4
2 is also ON, and the second cylinder 4B from the head side pipe line of the first cylinder 4A via this third electromagnetic switching valve 42.
Is connected to the bottom chamber of the first cylinder 4A and the second cylinder 4A.
The cylinder 4B constitutes a series circuit. Although two hydraulic pumps have been described in this embodiment, it is possible to configure a series circuit with one hydraulic pump.

The tilt / pitch selector switch 24 is turned on.
When N is set and the operation lever 22 is tilted diagonally forward left, the earthwork plate descends while pitching back to the soil carrying position. When the pitch speed changeover switch 25 is turned ON and the operation lever 22 is tilted diagonally right rearward, the earthwork plate moves at high speed. Then, the pitch is dumped while climbing, and the soil is discharged.

FIG. 12 is a hydraulic circuit diagram of an earthwork board device for a fourth bulldozer according to the present invention. Incidentally, this circuit diagram shows the pitch operation circuit, and the lift operation circuit is the same as the conventional one and is omitted. The discharge line of the hydraulic pump 30A is connected to the first directional control valve 20A. Hydraulic pump 30B
The discharge pipe line of is connected to the second directional control valve 20B.
The first directional control valve 20A and the second directional control valve 20B are connected to the first cylinder 4A and the second cylinder 4B. The hydraulic pumps 30A and 30B are fixed displacement hydraulic pumps, and 31A and 31B are cheering hydraulic pumps.
The discharge circuit of the support hydraulic pump 31A includes the support solenoid valve 4
It is connected to the hydraulic pump 30A discharge circuit via 3A. The discharge circuit of the support hydraulic pump 31B is connected to the discharge circuit of the hydraulic pump 30B via the support solenoid valve 43B.

The pitch dump changeover switch 25A and the pitch back changeover switch 24A are connected to the controller 47. The output signal of the controller 47 is input to the support solenoid valves 43A and 43B, the pitch dump control valve 44A and the pitch back control valve 44B, and the pitch / tilt switching solenoid switching valve 45, respectively. The discharge circuit of the pilot pump 27 is connected to the pilot pressure control valve 26 of the operating lever 22. The pilot pressure control valve 26 is connected to the pitch dump control valve 44A and the pitch back control valve 44B, and is also connected to the first directional control valve 20A via the electromagnetic switching valve 45. Further, the pilot pressure control valve 26 is connected to the second directional control valve 20B via the pitch dump control valve 44A and the pitch back control valve 44B.

Next, the operation lever 22 described in FIG.
The relationship between the operation positions of the pitch dump changeover switch 25A and the pitch back changeover switch 24A and the operation of the earthwork plate will be described with reference to FIG. Pitch dump changeover switch 25A and pitch back changeover switch 24A are turned off
When the operation lever 22 is tilted right, the earthwork plate tilts right, when tilted left, the earthwork plate tilts left, when tilted backward, the earthwork plate rises (lifts up), and when tilted forward, it descends ( Lift down).

When the pitch dump changeover switch 25A is turned on without using the operation lever 22, the earthwork plate is pitch dumped, and when the pitchback changeover switch 24A is turned on, the earthwork plate is pitched back.

As described above, when the pitch back changeover switch 24A is turned on and the operation lever 22 is tilted forward, the earthworking plate descends while pitching back to the soil carrying position.

When the pitch dump changeover switch 25A is turned on and the operation lever 22 is tilted rearward, the earthworking plate rises while pitch dumping and is in the earth discharging posture.

Next, the operation will be described. When the pitch back changeover switch 24A and the pitch dump changeover switch 25A are in the OFF state (the pitch dump control valve 44A and the pitch back control valve 44B are in the OFF B position), the operation lever 22 is operated to the left or the right (Fig. 13) The pilot pressure from the pilot control valve 26 is the pitch dump control valve 44A or the pitch back control valve 4
4B through the B position to be added to the operating portion of the second directional control valve 20B, the second directional control valve 20B is switched to the A position or the B position, and the pressure oil discharged from the hydraulic pump 30B is supplied to the second cylinder 4B. Flows into the head room or bottom room. At this time, the solenoid valve 45 is in the OFF position B, the pilot pressure from the pilot control valve 26 does not act on the first directional control valve 20A, and the second cylinder 4B is expanded and contracted.
The earthwork plate 10 can be tilted left and right.

When the pitch back changeover switch 24A of the operating lever 22 is turned on, the pitch back control valve 44B is set to A.
The electromagnetic switching valve 45 is switched to the position, the electromagnetic switching valve 45 is also switched to the A position, and the command signal from the controller 47 is input to the supporting electromagnetic valves 43A and 43B, so that the supporting electromagnetic valve 43.
Switch A and 43B to the A position. Therefore, the discharge flow rate from the support hydraulic pumps 31A and 31B is equal to that of the hydraulic pump 30.
Join the discharge pipes of A and 30B. At this time, the pilot pressure from the pilot pump 27 is supplied from the pitchback control valve 44B via the electromagnetic switching valve 45 to the first directional control valve 2
The operation portion of 0A and the pitchback control valve 44B directly add to the operation portion of the second directional control valve 20B. Therefore, the first directional control valve 20A and the second directional control valve 20B are switched to the B position, and the pressure oil discharged from the hydraulic pump 30A flows into the head chamber of the first cylinder 4A through the first directional control valve 20A. However, since the pressure oil discharged from the hydraulic pump 30B flows into the head chamber of the second cylinder 4B through the second directional control valve 20B, the first cylinder 4A and the second cylinder 4B are simultaneously shortened and the earthwork plate 10 Enables quick pitch back (backward tilt).

When the pitch dump changeover switch 25A of the operating lever 22 is turned on, the pitch dump control valve 44A is set to A.
The electromagnetic switching valve 45 is switched to the position, the electromagnetic switching valve 45 is also switched to the A position, and the command signal from the controller 47 is input to the supporting electromagnetic valves 43A and 43B, so that the supporting electromagnetic valve 43.
Switch A and 43B to the A position. Therefore, the discharge flow rate from the support hydraulic pumps 31A and 31B is equal to that of the hydraulic pump 30.
Join the discharge pipes of A and 30B. At this time, the pilot pressure from the pilot pump 27 is supplied from the pitch dump control valve 44A through the electromagnetic switching valve 45 to the first directional control valve 2
The operation portion of 0A and the operation portion of the second directional control valve 20B are directly added from the pitch dump control valve 44B. Therefore, the first
The directional control valve 20A and the second directional control valve 20B are switched to the A position, and the pressure oil discharged from the hydraulic pump 30A flows into the bottom chamber of the first cylinder 4A through the first directional control valve 20A and The pressure oil discharged from the pump 30B flows into the bottom chamber of the second cylinder 4B through the second directional control valve 20B, so that the first cylinder 4A and the second cylinder 4B are simultaneously extended and the earthwork plate 10 is pitch dumped ( It becomes possible to perform forward leaning quickly.

An embodiment in which the mounting positions of the first cylinder 4A and the second cylinder 4B of the earthwork plate according to the present invention are made asymmetric will be described with reference to FIG. FIG. 14A shows an earthwork plate 10, frames 3A and 3B, a first cylinder 4A,
It is a perspective view which shows the mounting state of the 2nd cylinder 4B. Figure 1
4 (b) is a plan view of the same. FIG. 14C is a side view of the same. FIG. 14D is a diagram showing the operating state of the first cylinder 4A and the second cylinder 4B. First, the first cylinder 4
The A and second cylinders 4B have front ends connected to the earthwork plate 10 with pins P1 and P2, and rear ends with pins P3 and P4, which are brackets 3A1 and 3B of the frames 3A and 3B.
It is attached to 1. Further, the tips of the frames 3A and 3B are connected to the earthwork plate 10 by pins P5 and P6. Here, the first cylinder 4A and the second cylinder 4B are the same cylinder, but the connecting pins P1 and P2 with the earthwork plate 10 at the tip end are provided at asymmetrical positions.
Specifically, the position of the connecting pin P2 on the back surface of the earthwork plate 10 is provided below the position of the connecting pin P1. That is, the distance between the connecting pin P1 position and the connecting pin P5 position is L
3, the distance between the connecting pin P2 position and the connecting pin P6 position is L
Assuming 4, L3> L4. Also, the connecting pin P
Distance between position 3 and connecting pin P5 is L5, connecting pin P
Let L6 be the distance between the 4th position and the connecting pin P6 position.
5 <L6. The position of the connecting pin P3 and the position of the connecting pin P4 are also asymmetrical positions. From the above, when the back surface of the earthwork plate 10 is vertical to the ground, the distance L8
(Distance between connecting pin P2 position and connecting pin P4 position)> distance L7 (distance between connecting pin P1 position and connecting pin P3 position).

Next, the operation will be described. 14
As shown in (d), when the back surface of the earthwork plate 10 is perpendicular to the ground, the rod of the first cylinder 4A is shortened in advance, while the rod of the second cylinder 4B is stretched in advance. is there. If both cylinders 4A and 4B are shortened at the same time from this state as shown in FIG. 14 (e), the first cylinder 4A comes to the stroke end first. In this state, the second cylinder 4B has not reached the stroke end yet, so if the second cylinder 4B is further shortened, the earthwork plate 10 will be in a tilted state. Since this is the case, the tilting operation of the earthworking plate 10 becomes possible due to the difference in the minimum stroke of the earthworking plate 10 during pitch back. Therefore, the tilt operation can be performed in the soil carrying attitude.

Further, the impact absorbing device for earthwork plate according to the present invention will be described with reference to FIG. The hydraulic pump 60 and the direction control valve 61 are connected. This directional control valve 61 is
A pipe 62 connects the head chambers of the lift cylinders 5A and 5B, and a pipe 63 connects the bottom chambers of the lift cylinders 5A and 5B. Also, the pilot pump 63
The pilot pressure discharged from the valve acts on the operating portions 61a and 61b of the directional control valve 61 via the pilot control valve 62 that is interlocked with the operating lever 62a. A branch conduit 62a is connected to the conduit 62, and the branch conduit 6a
A diaphragm 64 and an accumulator 65 are connected to 2a.

Next, the operation will be described. Due to the unevenness of the road surface during the work of the bulldozer, impact is constantly applied from the earthwork plate 10 through the lift cylinders 5A and 5B to the frame of the bulldozer, etc., and there is a problem in durability. Pipe line 62 on the head side of the lift cylinders 5A and 5B supporting the earthwork plate 10
When a pressure fluctuation occurs, the oil in the head oil chamber of the lift cylinders 5A and 5B flows into the accumulator 65 from the branch pipe line 62a through the throttle 64, and due to the spring action of the accumulator 65 and the pressure loss of the throttle 64 at this time. Vibration energy is absorbed by the damping action. For this reason earthwork plate 10
Vibrations of the lift cylinders 5A and 5B that support the vehicle are suppressed so that no impact is applied to the frame or the like of the bulldozer. The diaphragm 64 and the accumulator 65 are connected to the conduit 6
3 may be connected in series to suppress the vibration due to the pressure fluctuation generated in the pipelines on the bottom side of the lift cylinders 5A and 5B.

The present invention is also applicable to construction vehicles including small to large bulldozers.

[0069]

As described above in detail, according to the present invention, a large pitch back angle is set during soil loading and a large pitch dump angle is set during earth removal with respect to the attitude of the bulldozer during excavation. The amount of soil loaded on top is significantly increased, and the ground pressure distribution during soil transportation is more uniform than that of conventional bulldozers, increasing traction force and reducing soil resistance.
Further, it becomes easy to discharge the earthwork plate, and the working soil amount can be significantly increased even in a comparatively light vehicle without significantly increasing the vehicle body weight, the engine output and the like compared with the conventional bulldozer. Because of this, it has become possible to overcome the technical and economic problems of the past and to easily provide an ultra-large bulldozer that exceeds the current largest bulldozers.

Further, the earthmoving plate operating lever of the present invention, the tilt / pitch changeover switch, and the pitch speed changeover switch are provided, and three working postures of excavation posture, soil conveyance posture, and soil discharge posture can be selected by combining them. As a result, the operator can select the work posture corresponding to various soil types during operation, and the workability is improved.

Further, by using the switching operation means dedicated to the pitch dump and the switching operation means dedicated to the pitch back, it is possible to swiftly select and switch the excavation / earthing / earthing work of the bulldozer.

Further, since the earthmoving plate drive hydraulic device of the earthmoving plate device of the first bulldozer is provided with the main hydraulic pump and the support hydraulic pump, the earthmoving plate pitch back in excavation, soil transportation and earth discharging work can be performed. Only the main hydraulic pump is used when excavating and soiling the pitch dump work, and when the soil is discharged, the main hydraulic pump and the support hydraulic pump are used together, so the work can be done quickly. Moreover, since the support hydraulic pump is used only when necessary, power loss can be reduced.

Since the earthmoving plate drive hydraulic system of the earthmoving plate device of the second bulldozer is equipped with the variable displacement hydraulic pump, the discharge amount is reduced during the normal tilt and pitch operations in the excavation posture or the soil conveyance posture. Reduce power loss,
When in the earth unloading posture, the discharge amount is increased, and the pitch operation time of the earthwork plate can be shortened.

Further, the drive hydraulic device for the earthmoving plate of the earthmoving plate device of the third bulldozer is provided on the circuit connecting the first directional control valve and the second directional control valve with the first cylinder 4A and the second cylinder 4B. The first, second, and third electromagnetic switching valves are provided in the
Since the series circuit connects the one head side and the other bottom side of the second cylinder, the pitch operation time of the earthwork plate can be shortened in the earth unloading posture.

Further, since the lower part of the concave surface of the earthwork plate front plate is tilted backward with respect to the surface of the cutting edge of the earthwork plate, it becomes possible to load the soil on the earthwork plate, which increases the amount of soil to be transported and excavates. Since it is possible to prevent the soil that has been soiled from being consolidated on the front surface of the earthwork plate, it is possible to improve the soil separation when excavating the soil and improve the soil scavenging property. Further, by using the switching operation means dedicated to the pitch dump and the switching operation means dedicated to the pitch back, it is possible to swiftly select and switch the excavation / earthing / discharging work of the bulldozer.

When the back surface of the earthwork plate is perpendicular to the ground, the rod of the first cylinder 4A is shortened in advance, while the rod of the second cylinder 4B is stretched in advance. Since the two cylinders have different minimum strokes when the earthwork plate is pitched back, the tilting operation of the earthwork plate can be performed by further shortening one cylinder. Therefore, the tilt operation can be performed in the soil carrying attitude.

[Brief description of drawings]

FIG. 1 is a side view of an earthwork plate of the present invention.

FIG. 2 is a side view showing a situation when excavating the earthwork plate of the present invention.

FIG. 3 is a side view showing a condition of the earthwork plate of the present invention during soil transportation.

FIG. 4 is a side view showing a situation when the earthwork plate of the present invention is subjected to maximum pitch dumping.

FIG. 5 is a side view showing a state of the earthwork plate of the present invention during earth removal.

FIG. 6 is an explanatory view of the effect of the earthwork plate of the present invention during soil transportation.

FIG. 7 is a perspective view of an operation lever of the earthwork plate apparatus of the present invention.

FIG. 8 is an explanatory diagram of an operation position of an operation lever of the earthwork plate device of the present invention.

FIG. 9 is a circuit diagram of a first embodiment of a hydraulic device for operating an earthwork plate according to the present invention.

FIG. 10 is a circuit diagram of a second embodiment of a hydraulic device for operating an earthwork plate according to the present invention.

FIG. 11 is a circuit diagram of a third embodiment of a hydraulic device for operating an earthwork plate of the present invention.

FIG. 12 is a circuit diagram of a fourth embodiment of a hydraulic device for operating an earthwork plate according to the present invention.

FIG. 13 is an explanatory diagram of an operation position of an operation lever of another earthwork plate device of the present invention.

FIG. 14 is a first cylinder 4A connected to the earthwork plate of the present invention.
It is explanatory drawing which made the attachment position of the 2nd cylinder 4B asymmetric. (A) is the perspective view which looked at the earthwork board from the back, (b) is the same plan view, (c) is the same side view, (d), (e) is an operation explanatory view of the 1st cylinder and the 2nd cylinder.

FIG. 15 is a circuit diagram of a fifth embodiment of an earthwork plate impact mitigation device of the present invention.

FIG. 16 is a side view of a conventional bulldozer.

FIG. 17 is a front view of the same.

FIG. 18 is an explanatory diagram of the relationship between the traction force and resistance of the bulldozer during soil transportation and the driving force of the vehicle.

[Explanation of symbols]

4A ... 1st cylinder, 4B ... 2nd cylinder, 5A, 5B
... Lift cylinder, 10 ... Earthwork plate, 20A ... First directional control valve, 20B ... Second directional control valve, 21A, 21B ... Variable displacement hydraulic pump, 22 ... Operating lever, 24 ... Tilt /
Pitch changeover switch, 24A ... Pitch back changeover switch, 25 ... Pitch speed changeover switch, 25A ... Pitch dump changeover switch, 30A, 30B ... Hydraulic pump,
31 ... Supporting hydraulic pump, 32 ... Supporting solenoid valve, 35 ...
Electromagnetic switching valve, 40 ... First electromagnetic switching valve, 41 ... Second electromagnetic switching valve, 42 ... Third electromagnetic switching valve.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Naoki Kobayashi 3-1-1, Ueno, Hirakata, Osaka Prefecture Komatsu Ltd. Osaka factory (72) Hiroshi Itogawa 3-1-1, Ueno, Hirakata, Osaka Prefecture Komatsu Mfg. Co., Ltd. Osaka Plant (72) Inventor Noriaki Namiki 3-1-1 Ueno, Hirakata-shi, Osaka Prefecture Komatsu Mfg. Co., Ltd. Osaka Plant (72) Norihisa Matsumoto 3-1-1, Ueno, Hirakata-shi, Osaka Komatsu Ltd. Osaka Plant (72) Inventor Shigeru Yamamoto 3-1-1 Ueno, Hirakata, Osaka Prefecture Komatsu Ltd. Osaka Plant

Claims (30)

[Claims] 1. A frame (3A, 3A) mounted on both sides of a vehicle body.
In the earthwork plate device in which the earthwork plate (10) is attached to the tip of (B) so as to be swingable in the front-rear direction, the earthwork plate (10) is set at a predetermined angle from the excavated state at the time of earth movement with respect to the posture at the time of excavation. A method for controlling an earthwork plate of a bulldozer, which comprises tilting backward to increase the amount of soil carried. 2. The predetermined angle from the excavated state is 20
The method for controlling an earthwork plate of a bulldozer according to claim 1, wherein the degree is not more than °. 3. Frames (3A, 3A) mounted on both sides of the vehicle body
In the earthmoving plate device in which the earthmoving plate (10) is swingably attached to the tip of B) in the front-rear direction, the cutting edge angle of the earthmoving plate (10) is set to 35 mm.
A method for controlling an earthwork plate of a bulldozer, which comprises tilting backward so as to be equal to or more than 0 ° and increasing the amount of soil carried. 4. A frame (3A, 3A) mounted on both sides of a vehicle body.
In the earthmoving plate device in which the earthmoving plate (10) is attached to the tip of B) so as to be swingable in the front-rear direction, the earthmoving plate (10) is tilted forward by a predetermined angle during earth discharging to facilitate earth discharging. A method for controlling an earthwork plate of a bulldozer, which is characterized in that 5. The predetermined angle is 45 degrees from the excavated state.
The method for controlling an earthwork plate of a bulldozer according to claim 4, characterized in that the bulldozer is tilted forward to an angle of not more than °. 6. A frame (3A, 3A) mounted on both sides of a vehicle body.
In the earthwork plate device in which the earthwork plate (10) is attached to the tip of B) so as to be swingable in the front-rear direction, the cutting edge angle of the earthwork plate (10) is set to 10 mm.
A method for controlling an earthwork plate of a bulldozer, characterized in that the soil is easily discharged by leaning forward so as to be 0 ° or less. 7. A frame (3A, 3A) mounted on both sides of a vehicle body.
In the earthwork plate device in which the earthwork plate (10) is attached to the tip of (B) so as to be swingable in the front-rear direction, the earthwork plate (10) is set at a predetermined angle from the excavated state at the time of earth movement with respect to the posture at the time of excavation. The earthmoving plate control of the bulldozer is characterized in that the earthmoving plate (10) is tilted backward to increase the amount of soil transportation and the earthmoving plate (10) is tilted forward at a predetermined angle during earth discharging to facilitate earth discharging. Method. 8. A frame (3A, 3A) mounted on both sides of a vehicle body.
In the earthmoving board device in which the earthworking board (10) is attached to the tip of B) so as to be swingable in the front-rear direction, the earthworking board (10) is tilted backward from the excavated state to 20 ° or less during earth movement, The method for controlling an earthwork plate of a bulldozer according to claim 7, wherein the excavation state is tilted forward to 45 ° or less. 9. Frames (3A, 3A) mounted on both sides of the vehicle body
In the earthmoving plate device in which the earthmoving plate (10) is swingably attached to the tip of B) in the front-rear direction, the cutting edge angle of the earthmoving plate (10) is set to 35 mm.
The earthmoving plate of the bulldozer is characterized in that the amount of soil carried is increased by inclining backward so that it becomes more than 90 °, and the soil is easily discharged by inclining forward so that the cutting edge angle becomes less than 100 °. Control method. 10. A frame (3A, 3A, mounted on both sides of a vehicle body)
In the earthwork board device in which the earthwork board (10) is swingably attached in the front-back direction to the tip of (3B), the tilt / pitch switching means (24) for controlling the earthwork board (10) to tilt forward or backward, and the pitch. A speed changing means (25) is provided, and the tilt / pitch changing means (24), the pitch speed changing means (25), and the operation means (22) used for raising and lowering the earthwork plate are combined to perform the excavation posture and operation. The earthmoving plate control method for a bulldozer according to claim 7 or 8, characterized in that one of a soil attitude and an earth unloading attitude is selected. 11. A frame (3A, mounted on both sides of a vehicle body,
3B) is attached to the tip of the earthwork plate (10) so that it can swing back and forth, and the left and right ends of the earthwork plate (10) and the frame (3A, 3A).
B) and B are respectively connected by cylinders (4A, 4B), and by expanding and contracting these cylinders (4A, 4B), the earthwork plate (10) can be tilted left and right, and tilted forward or backward. In the earthwork plate device, a cylinder (4A, 4B) for controlling the rearward tilt angle to 5 ° or more and 20 ° or less with respect to the posture of the earthwork plate (10) during excavation, and a hydraulic drive device for the earthwork plate (10). Is a hydraulic pump (30A, 30B) that is a hydraulic power source, and a switching operation means (24) for switching between tilt operation and pitch operation.
And a directional control valve (20A, 20B) for controlling pressure oil to the cylinder (4A, 4B). 12. A frame (3A, mounted on both sides of a vehicle body,
3B) is attached to the tip of the earthwork plate (10) so that it can swing back and forth, and the left and right ends of the earthwork plate (10) and the frame (3A, 3A).
B) and B are respectively connected by cylinders (4A, 4B), and by expanding and contracting these cylinders (4A, 4B), the earthwork plate (10) can be tilted left and right, and tilted forward or backward. In the earthwork plate device, a cylinder (4A, 4B) for controlling the forward inclination angle to 5 ° or more and 45 ° or less with respect to the posture of the earthwork plate (10) during excavation, and a hydraulic drive device for the earthwork plate (10). Is a hydraulic pump (30A, 30B) that is a hydraulic power source, and a switching operation means (24) for switching between tilt operation and pitch operation.
And a directional control valve (20A, 20B) for controlling pressure oil to the cylinder (4A, 4B). 13. A frame (3A, mounted on both sides of a vehicle body,
3B) is attached to the tip of the earthwork plate (10) so that it can swing back and forth, and the left and right ends of the earthwork plate (10) and the frame (3A, 3A).
B) and B are respectively connected by cylinders (4A, 4B), and by expanding and contracting these cylinders (4A, 4B), the earthwork plate (10) can be tilted left and right, and tilted forward or backward. In the earthwork plate apparatus, a cylinder (4A, which controls the backward tilt angle to 5 ° to 20 ° and the forward tilt angle to 5 ° to 45 ° with respect to the posture of the earthwork plate (10) during excavation. 4B), the hydraulic drive system for the earthwork plate (10), a hydraulic pump (30A, 30B) as a hydraulic source, a switching operation means (24) for switching between tilt operation and pitch operation, and the cylinder ( 4A, 4B) Directional control valve (20
A, 20B) and bulldozer earthmoving board device. 14. A work implement pump for supplying pressure oil to the cylinders (4A, 4B) of the earthwork plate (10) is composed of a main hydraulic pump (30A, 30B) and a support hydraulic pump (31). Hydraulic pump (3
1) is connected to the discharge line of the main hydraulic pump (30A, 30B) via the electromagnetic switching valve (32), and the electromagnetic switching valve (32) constitutes a support circuit controlled by an external signal. Bulldozer earthwork board control device. 15. The earthwork plate apparatus according to claim 13, wherein the hydraulic pressure source of the drive hydraulic device for the earthwork plate (10) is the earthwork plate.
The working machine pump that supplies pressure oil to the cylinders (4A, 4B) of (10) is composed of the main hydraulic pump (30A, 30B) and the support hydraulic pump (31), and the support hydraulic pump (31) is The electromagnetic switching valve (32) is connected to the discharge line of the main hydraulic pump (30A, 30B), and the electromagnetic switching valve (32) constitutes a support circuit controlled by an external signal. Bulldozer earthmoving board device. 16. A frame (3A, mounted on both sides of a vehicle body)
3B) is attached to the tip of the earthwork plate (10) so that it can swing back and forth, and the left and right ends of the earthwork plate (10) and the frame (3A, 3A).
B) and B are respectively connected by cylinders (4A, 4B), and by expanding and contracting these cylinders (4A, 4B), the earthwork plate (10) can be tilted left and right, and tilted forward or backward. An earthmoving board device for a bulldozer, which is provided with an operating means (22) for the earthworking board (10), and a tilt / pitch switching means (24) and a pitch speed switching means (25). 17. The earthwork plate apparatus according to claim 16, wherein a rear tilt angle is 5 ° or more and 20 ° or less and a front tilt angle is 5 ° or more and 45 ° or less with respect to a posture of the earthwork plate (10) during excavation. An earthworking plate device for a bulldozer, comprising: a cylinder (4A, 4B) controlled in accordance with the invention; and an earthworking plate drive hydraulic device having the support circuit according to claim 14. 18. The earthwork plate apparatus according to claim 13, wherein the hydraulic source of the drive hydraulic device is a variable displacement hydraulic pump (21A, 21B), and the variable displacement hydraulic pump (21A, 21B).
An earthwork board device for a bulldozer, characterized in that B) is controlled by an external signal. 19. The earthwork plate apparatus according to claim 16, wherein a rear tilt angle is 5 ° or more and 20 ° or less and a front tilt angle is 5 ° or more and 45 ° or less with respect to a posture of the earthwork plate (10) during excavation. It is equipped with a cylinder (4A, 4B) to be controlled in accordance with the above and a drive hydraulic device for the earthwork plate (10), and the hydraulic source of the drive hydraulic device is a variable displacement hydraulic pump (21A, 21B). An earthwork board device for a bulldozer characterized by controlling pumps (21A, 21B) by an external signal. 20. The earthwork plate apparatus according to claim 13, wherein the hydraulic source of the drive hydraulic device is a fixed displacement hydraulic pump (30A, 30B), and the hydraulic oil from the hydraulic pump (30A, 30B) is used as a first hydraulic pump. It is connected to the bottom side conduit of the 1st cylinder (4A) and the head side conduit of the 1st cylinder (4A) and the 2nd cylinder (4A).
The bottom side pipe line of B) is connected via the electromagnetic switching valve (42), and the head side pipe line of the second cylinder (4B) is connected to the drain pipe line via the electromagnetic switching valve (41). Bulldozer earthwork board device characterized by the construction of a circuit. 21. The earthwork plate apparatus according to claim 16, wherein a rear tilt angle is 5 ° or more and 20 ° or less and a front tilt angle is 5 ° or more and 45 ° or less with respect to a posture of the earthwork plate (10) during excavation. Cylinders (4A, 4B) to be controlled in accordance with the above, and a drive hydraulic device for the earthwork plate (10) .The hydraulic source of the drive hydraulic device is a fixed displacement hydraulic pump (30A, 30B).
A, 30B) is connected to the bottom side conduit of the first cylinder (4A), and the head side conduit of the first cylinder (4A) and the bottom side conduit of the second cylinder (4B) are electromagnetically connected. A series circuit is configured by connecting through the switching valve (42) and connecting the head side pipeline of the second cylinder (4B) to the drain pipeline through the electromagnetic switching valve (41). Bulldozer earthwork board device. 22. Frames mounted on both sides of a vehicle body (3A,
3B) is attached to the tip of the earthwork plate (1
0), the angle of the lower end of the recess of the front plate of the earthwork plate (10) is inclined backward with respect to the surface of the cutting edge (12) attached to the lower end of the front surface of the earthwork plate (10). Bulldozer earthmoving board characterized by that. 23. Frames mounted on both sides of a vehicle body (3A,
3B) is attached to the tip of the earthwork plate (1
0), the angle of the lower end of the recess of the front plate of the earthwork plate (10) is inclined backward with respect to the surface of the cutting edge (12) attached to the lower end of the front surface of the earthwork plate (10). An earthwork plate device for a bulldozer according to any one of claims 11 to 13 and claims 15 to 21, characterized in that the earthwork plate (10) is provided. 24. Frames mounted on both sides of a vehicle body (3A,
3B) is attached to the tip of the earthwork plate (1
The angle at which the lower end of the recess of the front plate of the earthwork plate (10) is inclined backward with respect to the surface of the cutting edge (12) is set to 15 ° or less. Earthwork board. 25. Frames mounted on both sides of a vehicle body (3A,
3B) is attached to the tip of the earthwork plate (1
0), and the angle at which the lower end of the recess of the front plate of the earthwork plate (10) inclines backward with respect to the surface of the cutting edge (12) is set to an optimum value within the range of 15 ° or less. An earthwork plate device for a bulldozer according to any one of claims 11 to 13 and claims 15 to 21, characterized in that (10) is provided. 26. Frames mounted on both sides of a vehicle body (3A,
3B) is attached to the tip of the earthwork plate (10) so that it can swing back and forth, and the left and right ends of the earthwork plate (10) and the frame (3A, 3A).
B) and B are respectively connected by cylinders (4A, 4B), and by expanding and contracting these cylinders (4A, 4B), the earthwork plate (10) can be tilted left and right, and tilted forward or backward. In the earthwork board device, the cylinder is the first
It consists of a cylinder (4A) and a second cylinder (4B).
An earthwork plate device for a bulldozer, wherein the connecting position of the cylinder (4A) and the connecting position of the second cylinder (4B) are asymmetric. 27. The earthwork plate device for a bulldozer according to claim 26, wherein the rod lengths of the first cylinder (4A) and the second cylinder (4B) are the same. 28. The earthmoving board device for a bulldozer according to claim 26, wherein the first cylinder (4A) and the second cylinder (4B) are different in minimum rod length and / or stroke. 29. Frames mounted on both sides of a vehicle body (3A,
3B) is attached to the tip of the earthwork plate (10) so that it can swing back and forth, and the left and right ends of the earthwork plate (10) and the frame (3A, 3A).
B) and B are respectively connected by cylinders (4A, 4B), and by expanding and contracting these cylinders (4A, 4B), the earthwork plate (10) can be tilted left and right, and tilted forward or backward. An earthmoving board device for a bulldozer, comprising an operation means (22) for the earthworking board (10), a pitch dump switching means (25A) and a pitchback switching means (24A). 30. A pitch dump control valve (44A) receives a signal from the pitch dump switching means (25A) or a pitch back switching means (24A), or a pitch back control valve (44).
B) and a controller (47) that sends a command signal to the solenoid directional control valve (45) .The command signal from this controller (47) controls the support solenoid valves (43A, 43B) to the open position for support. The discharge flow rate from the hydraulic pump (31A, 31B) is adjusted to the main hydraulic pump (3
30. The earthwork plate apparatus according to claim 29, wherein a support circuit is formed to join the discharge conduits of 0A and 30B).