JP2002295413A - Hydraulic actuator - Google Patents

Abstract

(57) [Problem] To realize a two-port three-position hydraulic actuator with a simple configuration having a small number of parts. SOLUTION: A large diameter cylinder chamber 57 and a small diameter cylinder chamber 5 are provided.
8, a large-diameter portion 59 and a small-diameter portion 6 in a cylinder 51.
0 is movably accommodated. The piston 52 is provided with a piston rod 55 protruding outside the cylinder 51, and the displacement of the piston rod 55 is detected by a position detecting device 56. In the small-diameter cylinder chamber 58, a hydraulic port 61 and a bypass port 62 are formed with openings at intervals exceeding the axial length of the piston small-diameter portion 60. The piston 52 is stopped at three positions by utilizing the positional relationship between the ports 61 and 62 and the piston small diameter portion 60 and the pressure receiving area difference between the large diameter portion 59 and the small diameter portion 60.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an actuator having a plurality of stop positions, and more particularly, to a technique which is effective when applied to a control device of an automatic transmission having a plurality of transmission gear trains mounted on an automobile or the like. Things.

[0002]

2. Description of the Related Art A manual transmission (MT) that performs a shift operation by a driver's manual operation is an input shaft connected to an engine and having a plurality of drive gears mounted thereon, and a plurality of driven shafts paired with the drive gears. It has an output shaft on which gears are mounted and connected to drive wheels, and a plurality of transmission gear trains are provided between the input shaft and the output shaft. In this MT, after a clutch is disengaged at the time of shifting, the gear pair for transmitting power is manually switched from a plurality of transmission gear trains by a switching mechanism such as a synchromesh mechanism, and the clutch is connected. , A gear change operation, that is, a shift change is performed.

If the shift change and clutch operation are performed by a hydraulic actuator, an automatic transmission based on the configuration of a manual transmission can be obtained. This type of automatic transmission (Automated Manual Transmission; hereinafter abbreviated as AMT) having a plurality of transmission gear trains is compared with a normal torque converter type automatic transmission (AT) having a planetary gear or the like in an automatic transmission mechanism. It has the advantage that the number of parts is reduced, the weight can be easily reduced, and the transmission efficiency of the drive system is high.

In the AMT, when a shift change operation is performed by a hydraulic actuator, for example, a three-position actuator capable of shifting from a neutral position to a first speed and a second speed is used. As a three-position type actuator applied to such an automobile transmission, a two-port double-acting cylinder as disclosed in JP-A-9-72309 is known. There, two large-diameter and small-diameter pistons with different pressure receiving areas
Each stop is realized in a stepped cylinder having a small diameter portion, and three stop positions are realized by the mutual relationship between the large and small pistons.

That is, first, hydraulic pressure is supplied from behind both pistons, and the large-diameter piston is brought into contact with a step provided at the boundary between the large-diameter portion and the small-diameter portion to stop, and the small-diameter piston contacts the large-diameter piston. To form the first stop position. Next, when the hydraulic pressure behind the small-diameter piston is released from the first stop position and the hydraulic pressure is supplied between the two pistons from the large-diameter piston side, the small-diameter piston separates from the large-diameter piston, moves to the end of the small-diameter portion, and Two stop positions are formed. Further, when the hydraulic pressure behind the large-diameter piston is released from the first or second stop position and the hydraulic pressure is supplied behind the small-diameter piston, the large-diameter piston is pushed by the small-diameter piston and moves to the end of the large-diameter portion to stop at the third stop. A location is formed. Thus, three stop positions are realized by two ports, thereby reducing the number of operation valves.

[0006]

However, in such a conventional three-position actuator, since the piston is composed of two parts, the internal structure is complicated and the number of parts is increased, and the manufacturing cost is correspondingly increased. There was a problem of increasing. Also, since the number of sliding parts increases with the increase in the number of parts, the number of shielding parts such as O-rings also increases, and furthermore, grooves and the like are required for pistons and the like, resulting in further disadvantages in cost. there were.

An object of the present invention is to realize a two-port, three-position hydraulic actuator with a simple configuration having a small number of parts.

[0008]

A hydraulic actuator according to the present invention comprises a cylinder having a large-diameter cylinder chamber and small-diameter cylinder chambers formed at both ends of the large-diameter cylinder chamber and having a smaller diameter than the large-diameter cylinder chamber. A piston provided movably housed in the cylinder and having a large-diameter portion disposed in the large-diameter cylinder chamber, and a small-diameter portion disposed in the small-diameter cylinder chamber, and fixed to the piston; A piston rod that protrudes outside the cylinder and moves with the displacement of the piston, and that opens in the small-diameter cylinder chamber and is disposed along the axial direction at an interval exceeding the axial length of the piston small-diameter portion. And first and second hydraulic ports.

According to the present invention, a three-position hydraulic actuator can be constituted by a one-piece piston, so that the number of parts can be reduced and the cost of the product can be reduced.

[0010] The hydraulic actuator of the present invention may be provided with a position detecting means for detecting the displacement of the piston rod, whereby the operating condition of the hydraulic actuator can be accurately grasped.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a skeleton diagram illustrating an automatic transmission for a vehicle to which a hydraulic actuator according to an embodiment of the present invention is applied, and FIG. 2 is a cross-sectional view illustrating a configuration of the hydraulic actuator according to an embodiment of the present invention.

The engine 1 shown in FIG. 1 is provided with an electronically controlled throttle 2 for adjusting the engine torque and the engine speed. Usually, an output signal from an electronic control unit according to the depression amount of an accelerator pedal (not shown) is provided. To open and close the electronic control throttle 2 to perform engine control. In addition, the electronic control throttle 2 can be opened and closed by an actuator based on a detected operating state based on a detected map or the like to perform engine control, regardless of the accelerator pedal depression amount, as needed.

An automatic transmission for a vehicle that transmits power generated by an engine 1 to driving wheels includes an input shaft 4 connected to a crankshaft 3 of the engine 1 and an output shaft 5 parallel to the driving shaft and connected to the driving wheels. And A wet clutch 6 controlled by an actuator (not shown) is provided as an input clutch, that is, a main clutch, between the crankshaft 3 and the input shaft 4 of the engine 1, and connects and disconnects the engine 1 from the input shaft 4. This is done automatically. The wet clutch 6 includes a plurality of drive-side clutch disks 7 a provided on a clutch drum 7 fixed to the crankshaft 3 and a clutch hub 8 fixed to the input shaft 4.
And a plurality of driven-side clutch discs 8a provided in the main body. The engine 1 and the input shaft 4 are connected by crimping the drive-side clutch disk 7a and the driven-side clutch disk 8a. It is designed to be cut. ATF (Automatic Transmission) as lubricating oil is provided inside the wet clutch 6.
Fluid), and the controllability and durability are improved by the fluid friction and cooling effect of the ATF.

Drive gears 11 to 15 of first to fifth speed are rotatably mounted on the input shaft 4, and driven gears 21 to 25 of first to fifth speed are mounted on the output shaft 5. Has been fixed. Each of the drive gears 11 to 15 meshes with a corresponding driven gear 21 to 25 to form a speed change gear train, and a speed change operation is performed by switching the speed change gear train to transmit power.

A first speed drive gear 11 and a second speed drive gear 11
A first synchromesh mechanism 31 as a switching mechanism is provided between the high-speed drive gear 12 and the high-speed drive gear 12. Further, a second synchromesh mechanism 32 is provided between the third-speed drive gear 13 and the fourth-speed drive gear 14, and a third synchromesh mechanism 3 is provided adjacent to the fifth-speed drive gear 15.
3 are provided. The input shaft 4 and the output shaft 5 are each provided with a reversing gear (not shown), and by meshing both reversing gears via an idler gear (not shown), the rotation of the input shaft 4 is reversed to output. It is transmitted to the shaft 5.

The synchromesh mechanism 31 has a synchro hub 31a fixed to the input shaft 4 and a synchro sleeve 31b which always meshes with the synchro hub 31a.
When 1b meshes with a spline 11a integrally formed with the first speed drive gear 11, the gear ratio is set to the first speed, and conversely meshes with a spline 12a integrally formed with the second speed drive gear 12. Is set to the second speed. Similarly, the other synchromesh mechanisms 32, 33 also have synchro hubs 32a, 33a fixed to the input shaft 4 and synchro sleeves 32b, 33b that always mesh with them, respectively, and the splines 13a,
The gear ratio is set from the third speed to the fifth speed by engaging with one of 14a and 15a.

Each synchro sleeve 31b, 32
The shift change operation by the meshing movement of b and 33b in the axial direction is automatically performed by the hydraulic actuators 45 to 47. Here, in the automatic transmission for a vehicle in FIG. 1, each of the synchro sleeves 31b and 32b has a neutral position and two shift positions (first and second speeds, third and fourth speeds). I have. Therefore, a three-position actuator having three stop positions as shown in FIG. 2 is used for the hydraulic actuators 45 and 46.

As shown in FIG. 2, the hydraulic actuator 45 accommodates a piston 52 in a cylinder 51, and drives the piston 52 by supplying hydraulic oil through hydraulic oil supply ports 53 and 54. ing. A piston rod 55 is fixed to the piston 52, and a tip of the piston rod 55 protrudes from the cylinder 51. At one end of the piston rod 55, a position detecting device (position detecting means) 56 using a potentiometer or the like is provided so that the displacement of the piston rod 55 can be detected. Then, by operating the piston rod 55, the synchro sleeve 31b is driven, and a shift operation between the neutral speed and the first and second speeds is performed. Note that the hydraulic actuator 46 is also
Therefore, only the hydraulic actuator 45 will be described here.

In the hydraulic actuator 45 according to the present invention, a large-diameter cylinder chamber 57 is formed at the center of the cylinder 51, and small-diameter cylinder chambers having a smaller diameter than the large-diameter cylinder chamber 57 are provided at both ends of the large-diameter cylinder chamber 57. A communication 58 is formed. The piston 52 has a large-diameter portion 59 slightly smaller in diameter than the large-diameter cylinder chamber 57 and a small-diameter portion 60 slightly smaller in diameter than the small-diameter cylinder chamber 58. The large-diameter portion 59 is accommodated in the large-diameter cylinder chamber 57, and the small-diameter portion 60 is accommodated in the small-diameter cylinder chamber 58 so as to be movable in the axial direction (the left-right direction in FIG. 2).

In the small-diameter cylinder chamber 58, a hydraulic port (first hydraulic port) 61 and a bypass port (second hydraulic port) 62 are formed with openings at intervals along the axial direction. 61 and 62 are hydraulic oil supply ports 5
It communicates with 3,54. In this case, the small-diameter cylinder chamber 5
8 are provided with stoppers 63 with which the piston small diameter portions 60 abut.
3 is open to a hydraulic chamber 64 formed outside. The bypass port 62 is open near the boundary between the large-diameter cylinder chamber 57 and the small-diameter cylinder chamber 58, and has an interval between the bypass port 62 and the hydraulic port 61 that is at least larger than the axial length L of the piston small-diameter portion 60. Is provided. The bypass port 62 is formed at a position where the piston 52 is closed by the piston small diameter portion 60 when the piston 52 reaches the center position of the large diameter cylinder chamber 57.

A drain port 6 is provided at the center of the large-diameter cylinder chamber 57.
An opening 5 is formed. The drain port 65 is closed by the large diameter portion 59 when the piston 52 is located at the center of the large diameter cylinder chamber 57. When the piston 52 moves left and right, the base 66 of the large-diameter portion 59 and the large-diameter cylinder chamber 5 move.
The hydraulic oil in the large-diameter cylinder chamber 57 can be appropriately discharged by communicating with a gap formed between the inner cylinder 7 and the inner wall.

On the other hand, in the automatic transmission for a vehicle, the operation of the electronic control throttle 2, the wet clutch 6, and the shift change is performed automatically by actuators (not shown) and hydraulic actuators 45 to 47, respectively, as described above. Has become. The operation of these actuators is controlled by a control device 41 as control means. The control device 41 includes an engine speed sensor 42,
Signals from the input shaft speed sensor 43 and the ATF oil temperature sensor 44 are input. Accordingly, the control device 41 determines the engine speed Ne and the engine speed Nm of the input shaft 4 detected by the engine speed sensor 42 and the input shaft speed sensor 43, and the AT detected by the ATF oil temperature sensor 44.
The shift operation is automatically performed by judging the driving state of the vehicle from information such as the oil temperature of F and controlling the operation of each actuator based on a preset map.

Next, the shifting operation in the automatic transmission for a vehicle shown in FIG. 1 will be described. First, it is assumed that the driver operates the select lever provided in the vehicle cabin while the engine is driven to select neutral. At this time, the wet clutch 6 is held in a state where the engine 1 and the input shaft 4 are disconnected by the actuator controlled by the control device 41.

When the forward gear is selected by the select lever, the control device 41 controls the actuator to connect the wet clutch 6, and the engine 1 and the input shaft 4 are connected. At this time, the operation priority order of the wet clutch 6 is such that the synchro sleeve 31b is engaged with the spline 11a so that the first speed gear train is brought into the power transmission state, and then the wet clutch 6 is engaged. Let it. As a result, the power of the engine 1 is
Through the input shaft 4 so that the vehicle travels.

As the accelerator opening increases, the electronic control throttle 2 opens, and as the vehicle speed increases, an upshift operation is performed, and the vehicle speed decreases and the downshift occurs when the accelerator pedal is deeply depressed and a kick-down operation is performed. A shift operation is performed. During these shifting operations, the wet clutch 6 is in the disconnected state, and the engine speed is reduced by reducing the throttle valve. For example, the first
When the upshift is performed from the second speed to the second speed, the wet clutch 6 is disengaged, and the synchro sleeve 31b engaged with the spline 11a is engaged with the spline 12a of the second speed drive gear 12, and then the wet clutch 6 is engaged. To reconnect. On the other hand, when the downshift is performed from the second speed to the first speed, the wet clutch 6 is disengaged, and the wet clutch 6 is reconnected after the synchro sleeve 31b is engaged with the spline 11a. The same applies to an upshift operation and a downshift operation to another shift stage, and these shift operations are automatically performed according to a shift pattern programmed in the control device 41 in advance.

Here, the synchro sleeve 31b is driven by a hydraulic actuator 45 having three stop positions to switch between neutral, first speed and second speed. 3A to 3E are explanatory diagrams illustrating the operation of the hydraulic actuator 45. In FIG. 3, A ₁ , A ₂
Indicates pressure receiving areas at the large diameter portion 59 and the small diameter portion 60 of the piston 52, respectively.

FIG. 3A shows a configuration in a neutral state, and hydraulic pressures P ₁ and P ₂ are supplied to hydraulic oil supply ports 53 and 54, respectively. In FIG. 3A, since the bypass port 62 is closed by the piston small diameter portion 60, if P ₁ = P ₂ , both the small diameter portions 60 are set.
The hydraulic pressure applied to the cylinder is balanced, and the piston 52
7 is held at the center.

Next, hydraulic pressure is supplied from the hydraulic oil supply port 54.
Stop supplying hydraulic pressure from hydraulic oil supply port 53 while supplying
Then, the force F is applied to the piston small diameter portion 60 from the right side in the drawing.₁= P_Two
・ A ₁Is added, and the piston 52 moves to the left as shown in FIG.
Move to the side. At this time, the large-diameter cylinder chamber 57
Oil on the right side of the piston large diameter portion 59 is discharged from the drain port 65
The oil on the left side of the piston large diameter part 59 is
Discharged from 62. In the small-diameter cylinder chamber 58,
The oil on the left side of the piston small diameter portion 60
Is discharged.

When the piston 52 moves to the left, FIG.
As shown in (c), the left end of the small-diameter portion 60 eventually comes into contact with the stopper 63. As a result, the movement of the piston 52 is restricted, the position becomes the maximum displacement position of the piston rod 55, and by supplying hydraulic pressure to the hydraulic oil supply port 54, the piston 52 is moved by the force F ₁ = P ₂ · A ₁ . Held in position. Then, at this time, the synchro sleeve 31b meshes with the spline 11a and is shifted to the first speed.

On the other hand, when returning from the first speed to neutral
3C, the hydraulic oil supply port 53 is returned from the state shown in FIG.
Supply hydraulic pressure to At this time, the piston 52 has a pressure receiving area.
Is pushed back to the center based on the difference in That is, pis
Ton 52, F from the left_Two= A₁・ P₁+ A_Two・ P₁But,
F from right₁= P_Two・ A₁Is added. Therefore, the piston 5
2 has F '= F_Two-F₁= A₁(P₁−P_Two) + A_Two・ P₁
The force of P₁≒ P _TwoThen, the piston 52 becomes F '
≒ A_Two・ P₁Will be pushed rightward.

When the piston 52 moves to the center, the bypass port 62 closes, and as shown in FIG. 3D, the left and right pressing forces are balanced, and the piston 52 stops at the neutral position. However, when the hydraulic pressure from the hydraulic oil supply ports 53 and 54 is slightly different, the piston 52 is shifted to one side by the difference between the left and right pressing forces. FIG. 4 is an enlarged view of a portion A in FIG. 3E when, for example, P ₂ > P ₁ .

At this time, in part A, one of the bypass ports 62 is opened due to the displacement of the piston 52. The hydraulic pressure generated by the opening of the bypass port 62 causes the piston 5 to close in the direction of closing the other bypass port 62.
2 moves. The piston 52 repeats this operation and converges near the neutral position. Since the amplitude at this time is a very small value, there is no effect on the shift operation.

Further, when subsequently performing a shift operation to the second speed, while hydraulic pressure is supplied from the hydraulic oil supply port 53,
The supply of hydraulic pressure from the hydraulic oil supply port 54 is stopped. As a result, the piston 5 is displaced in the opposite manner to FIGS. 3B and 3C.
2 moves rightward and eventually comes into contact with the stopper 63 and stops at the maximum displacement position. When returning to neutral from there, contrary to FIGS. 3D and 3E, hydraulic pressure is again supplied from the hydraulic oil supply port 54 and the piston 52 is returned.
Push back to the left.

As described above, the hydraulic actuator 45
In this case, the piston 52 is not formed by a
A two-port, three-position hydraulic actuator can be configured with parts. Therefore, a three-position actuator can be realized without increasing the number of components and the number of shield components, and it is possible to reduce product cost.

The present invention is not limited to the above-described embodiment, and it goes without saying that various modifications can be made without departing from the scope of the invention.

For example, in the above-described embodiment, an example in which the hydraulic actuator of the present invention is applied to an automatic transmission for a vehicle has been described. It is applicable to various devices that require a position.

[0037]

According to the present invention, a piston having a large-diameter cylinder chamber and a small-diameter cylinder chamber is accommodated in a cylinder having a large-diameter cylinder chamber and a small-diameter cylinder chamber. Since the oil pressure is supplied from the port, 1
An actuator having three stop positions can be constituted by the piston composed of parts. Therefore, a 2-port 3-position hydraulic actuator can be configured without configuring the piston with a plurality of components, and the number of components and the number of shield components can be reduced, and the cost of the product can be reduced.

[Brief description of the drawings]

FIG. 1 is a skeleton diagram showing a vehicular automatic transmission to which a hydraulic actuator according to an embodiment of the present invention is applied.

FIG. 2 is a cross-sectional view illustrating a configuration of a hydraulic actuator according to one embodiment of the present invention.

FIGS. 3A to 3E are explanatory diagrams showing the operation of a hydraulic actuator.

FIG. 4 is an enlarged view of a portion A in FIG. 3 (e).

[Explanation of symbols]

 51 Cylinder 52 Piston 55 Piston rod 56 Position detecting device (Position detecting means) 57 Large diameter cylinder chamber 58 Small diameter cylinder chamber 59 Large diameter section 60 Small diameter section 61 Hydraulic port (first hydraulic port) 62 Bypass port (second hydraulic pressure) port)

Continued on the front page F term (reference) 3H081 AA02 AA04 AA05 BB02 CC23 DD33 FF04 FF14 FF47 GG04 HH08 3J552 MA04 MA13 NA01 NB04 PA65 PA66 QA01A

Claims (2)

[Claims] A cylinder having a large-diameter cylinder chamber, and small-diameter cylinder chambers formed at both ends of the large-diameter cylinder chamber and having a smaller diameter than the large-diameter cylinder chamber; movably accommodated in the cylinder; A piston provided with a large-diameter portion disposed in the large-diameter cylinder chamber and a small-diameter portion disposed in the small-diameter cylinder chamber, fixed to the piston, and protruding outside the cylinder;
A piston rod that moves in accordance with the displacement of the piston; first and second pistons that open in the small-diameter cylinder chamber and are arranged along the axial direction at intervals exceeding the axial length of the piston small-diameter portion; And a hydraulic port. 2. The hydraulic actuator according to claim 1, further comprising a position detecting means for detecting a displacement of said piston rod.