JP2000158959A - Driving device for crawler tractor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lessen a right-and-left width of a driving transmission system for connecting an engine, a transmission device, a hydraulic continuously variable transmission (HST) device and a differential mechanism, to make it compact, by displacing respective components of the driving transmission system in one direction, i.e., in the back-and-forth direction of a machine body. SOLUTION: An engine 3 is provided in a rear upper part of a hydraulic continuously variable transmission device 30, while a differential gear 17 is provided in a rear lower part of the HST device 30. An output shaft of the engine 3 is extended back and forth to be connected to a transmission case 5 and the HST device 30. An output shaft of the transmission case 5 is extended forth to be inputted in the differential gear 17, while an output shaft of the HST device 30 is extended back to be also inputted in the differential gear 17. A planetary gear mechanism constituting the differential gear 17 comprises only circumscribed gears, while a brake mechanism is provided in the driving input part of the differential gear 17 from the transmission case 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crawler tractor provided with a crawler type traveling device, and more particularly to a drive device for a roller tractor provided with a mechanical transmission device and a hydraulic type continuously variable transmission (HST device). Regarding the structure.

[0002]

2. Description of the Related Art Conventionally, after the output of an engine is shifted by a transmission device, it is input to a differential mechanism and transmitted to the left and right axles to drive straight ahead, and the HST device is driven by operating a steering handle. A technique is known in which a driving force from a vehicle is input to the differential mechanism to cause a rotational drive difference between the left and right axles to perform a turning travel.
Japanese Patent Application Laid-Open No. Hei 8-99565 discloses a configuration in which the brake lever is strengthened by operating the accelerator lever toward the low-speed rotation of the engine in conjunction with the operation of the brake pedal.

[0003]

However, in the aforementioned differential mechanism, one of the gears constituting the planetary gear is
Since the internal gear is used, there is a problem that the planetary gear device becomes large in the radial direction, and since the internal gear has a large number of teeth, there is also a problem that the machining cost increases. In addition, the conventional brake mechanism described above is provided with a steering brake on the left and right axles to perform left-right turning travel, and is also used as a travel brake.However, since a large torque needs to be braked, the configuration of the brake mechanism is large. There was a problem of becoming. Also, maintenance is difficult because the brake mechanism is inside the differential case.

[0004]

The present invention uses the following means in order to solve the above problems. That is, in a crawler tractor equipped with a traveling transmission device and a turning hydraulic continuously variable transmission, the output shaft of the engine is extended rearward and connected to the transmission device, and the output shaft of the engine is extended forward. Connected to the hydraulic continuously variable transmission, and further extending the output shaft from the transmission device to input to the differential mechanism, and extending the output shaft from the hydraulic continuously variable transmission to It was configured to input to the mechanism.

Further, the hydraulic continuously variable transmission is disposed at the front of the body, the engine is disposed above the rear of the hydraulic continuously variable transmission, and the engine is disposed at the rear of the hydraulic continuously variable transmission. And the differential device is disposed below.

A crawler tractor having a structure in which engine output is input to a differential mechanism via a traveling mission device and engine output is input to the differential mechanism via a turning hydraulic continuously variable transmission is provided. The planetary gear mechanism constituting the differential mechanism is constituted only by the external gear.

A crawler tractor having a structure in which engine output is input to a differential mechanism via a traveling transmission device and engine output is input to the differential mechanism via a turning hydraulic continuously variable transmission is provided. A brake mechanism is provided at a drive input portion of the differential device from a transmission device.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The problems and means to be solved by the present invention are as described above. Next, an embodiment of the present invention shown in the attached drawings will be described. 1 is an overall side view showing a crawler tractor, FIG. 2 is a plan view thereof, FIG. 3 is a side view showing a chassis portion of the crawler tractor, FIG. 4 is a plan view thereof, FIG. 5 is a side view of a differential case, and FIG. It is a plane sectional view showing a differential mechanism.

First, the schematic configuration of the crawler tractor will be described. As shown in FIGS. 1 and 2, an engine 3 is disposed above a front portion of a pair of left and right crawler traveling devices 1, and a transmission case 5 is disposed above a rear portion. The engine 3 is covered with a hood 4 and the engine 3
The axle bracket 6 protrudes forward from the portion. A steering handle 7 for performing a steering operation is disposed behind the hood 4, and a seat 8 is disposed behind the steering handle 7 to constitute a driving unit. Behind the seat 8, a safety frame 9 stands upright. A three-point link hitch 10 for mounting various working machines is provided at the rear end of the machine.

The crawler-type traveling device 1 is supported by a crawler frame 2 and includes a driving sprocket 11 at a front end, an idler 12 at a rear end, and a roller disposed between the driving sprocket 11 and the idler 12. Wheel 13 ・ 13
The crawler belt 14 is wound around.

Next, the drive transmission system of the crawler tractor will be described. 3 and 4, a transmission case 5 is connected to the rear of the engine 3 and is connected to the engine 3.
An axle bracket 6 extends forward from left and right sides of the vehicle, and a differential case 20 is fixed to the axle bracket 6.

The differential case 20 includes a differential 17, axle cases 18 extending left and right from the differential 17, and a final reduction gear disposed at the tip of the axle case 18. 19 and 19 are integrally connected, and the final reduction gear 19
A drive sprocket 11 is connected to each of 19.

A drive shaft 21 extending forward from the transmission case 5 is connected to the differential 17.
The driving force from the engine 3 that has been decelerated in the transmission case 5 is input into the differential 17 through the drive shaft 21. The driving force input into the differential 17 is transmitted to the final reduction gears 19 through the axles in the left and right axle cases 18 after being reduced in speed, and further reduced in the final reduction gears 19 to drive the left and right driving sprockets. 11 is driven.

Crawler frames 2 are arranged on the left and right sides of the engine 3 and the transmission case 5, and the front end 2a of the crawler frame 2 is attached to the final reduction gear 19 of the differential case 20, and the rear is the rear. It is attached to the transmission case 5 via a support bracket 26. Further, a front portion of the crawler frame 2 is supported by the axle bracket 6 via a front support bracket 27.

An idler 12 is rotatably supported at the rear end of the crawler frame 2. Rollers 13, 13... Rotate at a portion between the drive sprocket 11 and the idler 12 of the crawler frame 2. Freely supported,
Drive sprocket 11, idler 12, and wheel 13
The crawler 14 is wound around 13.

A steering hydraulic continuously variable transmission (hereinafter, referred to as an HST device) 30 is disposed in front of the engine 3, and a hydraulic pump 31 of the HST device 30 has a pump drive shaft 22. , And a reduction gear case 16. Then, after the output of the engine 3 is reduced through the reduction gear case 16, the output is input to the hydraulic pump 31 of the HST device 30, and the hydraulic pump 3 is driven according to the operation amount of the steering handle 7.
The output amount from the hydraulic pump 31 is adjusted, and the output shaft 23 of the hydraulic motor 32 driven according to the discharge amount of the hydraulic pump 31 is driven.

The output shaft 23 is connected to the differential 17 to transmit a rotational driving force into the differential 17, and by operating the steering handle 7, the number of rotations and the direction of rotation are changed. It is configured so that: By operating the steering handle 7 to change the rotation speed and rotation direction of the output shaft 23, the differential
The steering speed is adjusted by adjusting the number and direction of drive rotation transmitted to the left and right drive sprockets 11 from the vehicle.

As described above, in the drive transmission system of the crawler tractor of the present embodiment, the output shaft of the engine 3 extends forward and backward, and is interlocked and connected to the transmission case 5 at the rear, and the HST device 30 at the front. And the drive shaft 2 which is the output shaft of the transmission case 5
1 is extended forward and input to the differential mechanism 17 in the differential case 20, and the output shaft 23 of the HST device 30 is extended rearward and input into the differential mechanism 17.

As a result, the drive transmission system that connects the engine 3, the transmission case 5, the HST device 30, and the differential mechanism 17 can be arranged in the same direction in the front-rear direction of the fuselage. A small and compact configuration can be achieved.

Since the engine 3 is arranged at the upper part behind the HST device 30 and the differential mechanism 17 (differential case 20) is arranged at the lower part behind the HST device 30, as shown in FIG. , HST device 30
Drive shaft 22 as an input shaft to the HST device 30
The output shaft 23 is arranged in a substantially parallel position in the vertical direction, and a small drive width can be obtained with a small lateral width.
Since the input shaft and the output shaft of the T device 30 are arranged on the same side, the HST device 30 can have a simple configuration.

Next, the configuration of the differential mechanism 17 will be described with reference to FIG. The output of the engine 3 is input to the differential mechanism 17 in the differential case 20 by the drive shaft 21 via the transmission case 5. The driving force of the drive shaft 21 is transmitted to a bevel gear 42 fixed to the input shaft 43 via a bevel gear 41 fixed to the drive shaft 21 to drive the input shaft 43. And the input shaft 43
Is divided into right and left, and is input to the left and right planetary gear mechanisms 40L and 40R constituting the differential mechanism 17. The left and right planetary gear mechanisms 40L and 40R each have a sun gear 4
4L / 44R, planetary gears 45L / 45R, carriers 46L / 46R / 48L / 48R, and output gear 47
L · 47R and the like.

The rotation output of the input shaft 43 drives the sun gears 44L and 44R fixed to the left and right ends of the input shaft 43 to rotate in the same direction and at the same rotational speed. And the sun gear 44
L ・ 44R are left and right planetary gears 45L ・
Gear 4 which is one of two gears engraved on 45R
5La • 45Ra, and the other gear 45Lb
45Rb meshes with the output gears 47L and 47R, respectively. Here, the planetary gear 45L is connected to the input shaft 43.
One end is rotatably supported by the carrier 46L loosely fitted on the top and the other end is rotatably supported by the carrier 48L loosely fitted on the drive output shaft 49L.
It is rotatably supported so as to be sandwiched by the 48L, and rotates on the outer periphery of the input shaft 43 (drive output shaft 49L) integrally with the carriers 46L and 48L. Similarly, the planetary gear 45R is made up of carriers 46R and 48R.
It is supported rotatably as if sandwiched between
The input shaft 43 is integrated with the carriers 46R and 48R.
(The drive output shaft 49R).

As described above, in the differential mechanism 17, all the planetary gear mechanisms 40L and 40R disposed to be opposed to each other on the left and right are constituted by external gears. For this reason, the size in the radial direction is smaller than a conventional planetary gear having an internal gear as a component,
It is possible to have a compact configuration, and it is possible to secure a large height above the ground of the aircraft, thereby improving travelability. In addition, since the processing cost is smaller than that of the internal gear, the manufacturing cost can be reduced.

In the differential mechanism 17 configured as described above, when the operation by the steering handle 7 is maintained at the neutral position, the output shaft 23 of the hydraulic motor 32 of the HST device 30 does not rotate. The bevel gear 51 fixed on the output shaft 23 is fixed, and the bevel gears 52L and 52R and the reverse output gears 54L and 54R fixed on the revolving shafts 53L and 53R, respectively.
Is also fixed, and a braking action is generated on the left and right carriers 46L and 46R that mesh with the reverse rotation output gears 54L and 54R. As a result, the carriers 46L and 46R are connected to the input shaft 4
3 to maintain a substantially fixed state without rotating.

As a result, the planetary gear 4
The 5L (45R) is driven to rotate on the carriers 46L and 48L (46R and 48R) without rotating on the outer periphery of the input shaft 43. By rotating the output gears 47L and 47R that mesh with the gears 45Lb and 45Rb of the planetary gears 45L and 45R,
The left and right drive output shafts 49L and 49R are rotationally driven. That is, when the steering handle 7 holds the neutral position, only the output from the engine 3 via the transmission case 5 is input into the differential mechanism 17, and the left and right drive output shafts 49L and 49R are connected. It is driven to rotate at the same rotation speed and direction.

On the other hand, when the steering handle 7 is turned left and right, the discharge amount of the hydraulic pump 31 of the HST device 30 is adjusted according to the operation amount of the steering handle 7, and the output shaft 23 of the hydraulic motor 32 rotates accordingly. Driven. Then, the differential mechanism 1 is driven by the output shaft 23.
The rotation output input to the inside 7 drives the bevel gears 52L and 52R fixed on the left and right turning reverse shafts 53L and 53R through the bevel gear 51 in reverse rotation and rotation at the same rotation speed.

Thus, the left and right carriers 46L and 46R meshing with the reverse rotation output shafts 54L and 54R also rotate in the reverse direction and rotate around the outer circumference of the input shaft 43 at the same rotation speed. Then, the planetary gears 45L and 45R are rotated integrally with the carriers 46L and 48L or the carriers 46R and 48R on the outer circumference of the input shaft 43 by the rotation of the carriers 46L and 46R at the same rotation speed. The carriers 46L and 46 of the planetary gears 45L and 45R
R and the planetary gears 45L / 4
If the rotation direction of the 5R with respect to the input shaft 43 is the same,
The number of revolutions of the output gear 49L (or 49R) is added,
If it is in the opposite direction, the rotation speed of the output gear 49L (or 49R) is subtracted.

That is, the output of the engine 3 via the transmission case 5 and the output of the engine 3 via the HST device 30 are combined in the differential mechanism 17 to generate a rotational difference between the left and right drive output shafts 49L and 49R. As a result, the driving sprockets 11 of the right and left crawler traveling devices 1
11, a rotation difference is generated, and the vehicle can turn to the left or right.

As shown in FIG. 6, a plurality of (two in this embodiment) brake plates 64 are slidable on the drive shaft 21 in the axial direction of the drive shaft 21. Each of the brake plates 64 and 64 is supported so as not to rotate relative to the drive shaft 21, and is provided in the vicinity of each of the brake plates 64.
5 are provided. A brake shoe 63 is disposed near one side of the brake plates 64, 64, and the brake shoes 63 are urged by springs 63a in a direction opposite to the brake plates 64, 64. With the above configuration, when a brake pedal (or a brake lever or the like, not shown) is operated by a driver's operation, the cam 62 rotates to press the brake shoe 63 according to the rotation of the brake arm 61, The brake shoe 63 is pressed against the brake plates 64 and 64 against the tension of the spring 63a. As a result, a frictional force is generated between the brake plates 64, 64, the brake mating plates 65, 65, and the brake shoes 63, and a braking action is generated on the drive shaft 21.

As described above, since the crawler tractor of this embodiment is capable of turning using the turning HST device 30, the turning mechanism is provided by providing a brake mechanism on the left and right axles as in the prior art. As described above, a brake mechanism can be provided at the input portion from the transmission case 5 to the differential mechanism 17 (at a position before the engine output is divided into left and right), and one brake mechanism is provided. It is possible to reduce the cost, and the brakes mounted on the left and right axles need to brake large torque, so a large brake mechanism was required, but the brake mechanism can be configured with a compact configuration. became. In addition, since the brake mechanism is disposed at the input portion of the differential case 20, the maintenance is excellent.

[0031]

According to the present invention, the following effects can be obtained by the configuration described above. That is, in a crawler tractor equipped with a traveling transmission device and a turning hydraulic continuously variable transmission, the output shaft of the engine is extended rearward and connected to the transmission device, and the output shaft of the engine is extended forward. Connected to the hydraulic continuously variable transmission, and further extending the output shaft from the transmission device to input to the differential mechanism, and extending the output shaft from the hydraulic continuously variable transmission to Because it was configured to input to the mechanism,
The drive transmission system that connects each of the engine, transmission, hydraulic continuously variable transmission, and differential mechanism can be arranged in the same direction in the front-rear direction of the fuselage. You can do it.

Further, the hydraulic continuously variable transmission is disposed at the front of the body, the engine is disposed above the rear of the hydraulic continuously variable transmission, and the engine is disposed at the rear of the hydraulic continuously variable transmission. In this configuration, the input shaft and the output shaft of the hydraulic continuously variable transmission are arranged substantially in parallel in the vertical direction, so that the drive transmission configuration has a small left-right width and is compact. It has become possible. In addition, since the input shaft and the output shaft of the hydraulic continuously variable transmission are arranged on the same side, the hydraulic continuously variable transmission can have a simple configuration.

Also, in a crawler tractor having a configuration in which engine output is input to a differential mechanism via a traveling transmission device and engine output is input to the differential mechanism via a turning hydraulic continuously variable transmission. Since the planetary gear mechanism constituting the differential mechanism is constituted only by the external gear,
Compared to a conventional planetary gear having an internal gear as a component, the size in the radial direction is smaller and a compact configuration can be achieved. In addition, since the processing cost is smaller than that of the internal gear, the manufacturing cost can be reduced.

A crawler tractor having a configuration in which engine output is input to a differential mechanism via a traveling transmission device and engine output is input to the differential mechanism via a turning hydraulic continuously variable transmission is provided. Since the brake mechanism is provided in the drive input portion of the differential device from the transmission device, only one brake mechanism is required, and the cost can be reduced. Also, in the prior art, the brake mechanisms mounted on the left and right axles needed to brake large torques, so large ones were required. However, in the configuration of the present invention, the brake mechanism should be configured with a compact configuration. Became possible. Further, since the brake mechanism is arranged at the input portion of the differential case, the maintenance is excellent.

[Brief description of the drawings]

FIG. 1 is an overall side view showing a crawler tractor.

FIG. 2 is a plan view of the same.

FIG. 3 is a side view showing a chassis part of the crawler tractor.

FIG. 4 is a plan view of the same.

FIG. 5 is a side view of a differential case.

FIG. 6 is a plan sectional view showing a differential mechanism.

[Explanation of symbols]

 3 Engine 5 Transmission case 17 Differential gear 20 Differential case 40L / 40R Planetary gear mechanism 41 Bevel gear 42 Bevel gear 43 Input shaft 44L / 44R Sun gear 45L / 45R Planetary gear 46L / 46R Carrier 47L / 47R Output gear 48L / 48R Carrier 49L / 49R drive output shaft 51 bevel gear 52L / 52R bevel gear 53L / 53R turning reverse rotation shaft 54L / 54R reverse rotation output gear 64 brake plate 65 brake mating plate

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Takashi Uno 1-32 Chaya-cho, Kita-ku, Osaka-shi, Osaka Prefecture F-term in Yanmar Diesel Co., Ltd. 3D035 CA26 CA27 3D039 AA03 AA04 AA05 AB12 AB22 AC21 AC24 AC26 AC32 AD53 3D042 AA06 AB10 AB12 BA02 BA04 BB01 BB02 CA01 CA06 CA08 CA09 CB01 CB12 CB17 CB20 3J058 AA44 AA48 AA53 AA59 AA79 BA62 BA63 BA67 CA41 CB15 CB17 CC08 CC52 FA12

Claims (4)

[Claims] 1. A crawler tractor comprising a traveling transmission device and a turning hydraulic continuously variable transmission, wherein an engine output shaft is extended rearward and connected to the transmission device, and the engine output shaft is connected to the transmission device. Extending forward and connecting with the hydraulic continuously variable transmission, further extending the output shaft from the transmission device and inputting it to the differential mechanism,
A drive device for a crawler tractor, wherein an output shaft from a hydraulic continuously variable transmission is extended and input to a differential mechanism. 2. The hydraulic continuously variable transmission is disposed at a front portion of an airframe, the engine is disposed above a rear portion of the hydraulic continuously variable transmission, and the engine is disposed at a rear portion of the hydraulic continuously variable transmission. 2. The drive device for a crawler tractor according to claim 1, wherein the differential device is disposed below the crawler tractor. 3. A crawler tractor having a configuration in which engine output is input to a differential mechanism via a traveling transmission device and engine output is input to the differential mechanism via a turning hydraulic continuously variable transmission. A crawler tractor drive device, wherein the planetary gear mechanism constituting the differential mechanism is constituted only by external gears. 4. A crawler tractor having a structure in which engine output is input to a differential mechanism via a traveling transmission device and engine output is input to the differential mechanism via a turning hydraulic continuously variable transmission. A drive mechanism for a crawler tractor, wherein a brake mechanism is provided at a drive input portion of the differential device from a transmission device.