JP2002187567A - Push cylinder device for travelling vehicle and the like - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve an unwanted operation by leak pressure oil of a piston operated by pressure oil fed to a push cylinder and a drawback caused by a shared use of the push cylinder. SOLUTION: A push cylinder device for a traveling vehicle and the like has clutch pistons 4 operated by pressure oil fed to the push cylinder 3 via a switching movement of a hydraulic selector valve 1, and double-acting brake pistons 5 loosely fitted in the clutch pistons 4. Each of the brake pistons 5 has a relief oil passage 6 for leak pressure oil, which is closed when the related clutch piston 4 is operated over a stroke s to disengage a steering clutch 7. When a double action of only the brake piston 5 successively brakes a traveling brake 8, the outside diameter of the brake piston 5 can be changed to change thrust in the braking action.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a push cylinder device for a traveling vehicle or the like, and to a field in which a steering clutch and a traveling brake of a traveling transmission case are operated when the traveling vehicle or the like advances.

[0002]

2. Description of the Related Art When steering control in the traveling direction is performed in a traveling vehicle or the like, a steering clutch and a traveling brake provided in a traveling mission case are turned on and off by a hydraulically driven push cylinder device. It was common to perform steering turning and braking to the left and right sides.

[0003]

However, in such a push cylinder device, a double-acting type in which a brake piston for braking a traveling brake is loosely fitted in a clutch piston for disengaging a steering clutch, When the clutch piston is operated, a leak pressure is applied to the other clutch piston and the brake piston, and there is a fear that the clutch piston may be unintentionally operated when not operated. Further, when this push cylinder device is commonly used for a large or small traveling vehicle, there is a problem in that the braking feeling is too strong in the case of a small size and the operation feeling is deteriorated.

[0004] In view of the above, it is intended to improve the undesired operation of the piston due to the leak pressure as described above and the difficulties caused by sharing the push cylinder device.

[0005]

According to the first aspect of the present invention, there is provided a clutch piston 4 operated by pressurized oil sent to a push cylinder 3 by switching a hydraulic switching valve 1, and a plurality of clutch pistons loosely fitted in the clutch piston 4. In the brake piston having an operation type, the brake piston 5 is provided with a leak oil passage 6 for leaking pressure oil which connects between a pressure receiving surface p and a tank port t for returning oil to an oil tank. The relief oil passage 6 is closed when the piston 4 operates the disengagement stroke s of the steering clutch 7 to constitute a push cylinder device for a traveling vehicle or the like.

According to a second aspect of the present invention, after the clutch piston 4 is operated by the disengagement stroke s of the steering clutch 7,
3. The thrust force at the time of the braking action can be changed by changing the outer diameter of the brake piston, wherein the driving action of the traveling brake 8 is subsequently performed by the double action of only the brake piston 5. The configuration of the push cylinder device for a traveling vehicle or the like described above.

[0007]

According to the first aspect of the present invention, the switching stroke of the hydraulic pressure switching valve 1 sends pressure oil from the oil tank to the push cylinder 3 and disconnects one clutch piston 4 from the steering clutch 7. After the operation, the brake piston 5 is slid from the inside of the clutch piston 4 by the flow of the pressure oil to be protruded. At this time, the pressure is applied to the other clutch piston 4 and the brake piston 5 side. Since the oil leaks, the leak pressure can be released by allowing the leak pressure oil to escape from the pressure receiving surface p of the brake piston 5, pass through the oil passage 6 and return to the oil tank via the tank port t. Further, when the clutch piston 4 is operated, the relief oil passage 6 can be closed by the inner wall of the push cylinder 3, so that when the brake piston 5 is operated, the pressure oil does not escape and the entire pressure can be applied.

According to the second aspect of the present invention,
When the clutch piston 4 and the brake piston 5 are operated as described above, the outer diameter of the brake piston 5 is changed to be large or small with respect to the clutch piston 4, so that the braking force by the operation of the piston 5 is made strong or weak. Can be adjusted.

[0009]

According to the first aspect of the present invention, as described above,
By providing a relief oil passage 6 for leak pressure oil in the brake piston 5, when one of the clutch pistons 4 operates,
Since the leakage pressure generated in the other clutch piston 4 and the brake piston 5 can be released, unintended operation of the brake piston 5 when not operating is suppressed, and steering turning and braking to the left and right sides when the vehicle is running can be performed. In addition to being able to perform the operation accurately, the relief oil passage 6 can be closed when the brake piston 5 is operated. Steering turning and braking can be performed sharply.

According to the second aspect of the present invention, as described above, the outer diameter of the brake piston 5 with respect to the clutch piston 4 can be changed to be large or small to adjust the braking force to be strong or weak. In the case of a traveling vehicle or the like, it is possible to reduce the outer diameter of the brake piston 5 to reduce the braking force. Can be operated with a good feeling.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings as to a combine as a traveling vehicle. FIG. 12 shows the overall configuration of the combine, in which a traveling device 11 having a pair of left and right traveling rollers 10 traveling on the soil surface is provided below the chassis 9 and a filter is provided.
A threshing device 13 for threshing the harvested culm supplied by being pinched and conveyed to the dochen 12, a grain tank 15 for storing grains provided with a threshing auger 14 for discharging the threshed grains outside the machine, Is mounted on the chassis 9.

In front of the threshing device 13, a weeding body 16 for weeding uncut culms from the front end side thereof, a raising portion 17 for causing weeded culms, and a cutting blade for cutting the raised culms. A harvesting section having a section 18 and a grain stalk transport section 19 for transporting the harvested grain stalk to the feed chain 12 while adjusting the handling depth while transporting the harvested grain stalk backward. The apparatus 20 is arranged so as to be raised and lowered on the soil surface by a hydraulically driven mowing cylinder 21.

An operating device 22 for controlling the operation of the combine is provided on one side of the reaper 20 and an operating seat 2 for this operation.
3, the Glen tank 15 is disposed behind the operation seat 23, and the engine 24 is mounted below the Glen tank 15.
These traveling device 11, threshing device 13, reaping device 20,
The vehicle body 25 is constituted by the operation device 22, the engine 24, and the like.

A traveling transmission case 26 is mounted on the front end side of the undercarriage 9 and, as shown in FIGS.
7, output transmission shaft 28, intermediate shaft 29, steering clutch shaft 3
0, the left and right traveling shafts 31 are respectively supported.
The shaft portion of the input transmission shaft 27 protruding outward from the gear 26
An input pulley 33 transmitted from the engine 24 by a transmission belt 32 and a mowing drive pulley 34 for transmitting power to the mowing device 20 are each configured to be axially stopped.

The input and output pulley shafts are removably protruded from the transmission case 26 to the input shift shaft 27 and the output shift shaft 28 on the side opposite to the input pulley 33 by spline fitting or the like. The input and output speed change pulleys 35 and 36 of split pulley type are respectively supported on the portions 27A and 28A, and the continuously variable speed belt 3 is interposed between the speed change pulleys 35 and 36.
7, a belt case 38 covering the transmission portion is attached to the transmission case 26 so as to be openable and closable.

A ring gear 40 which rotates in mesh with an input drive gear 39 fixed to the input transmission shaft 27 and a sun fixed to the output transmission shaft 28 via a planetary gear 41 inside the ring gear 40. The planetary gear mechanism G is axially mounted on a transmission gear 45 that is integrally rotated by a planetary shaft 43 that supports the planetary gear 41 and a carrier 44 that fixes the planetary shaft 43, while the gear 42 is meshed and linked.

The speed change pulleys 35 and 36, which are supported by the pulley shaft portions 27A and 28A, change the pulley interval in each axial direction, that is, the pulley diameter is changed, and the continuously variable speed belt 37 is provided.
Continuously variable transmission by transmission of The transmission gear 45 and an intermediate gear 46 supported by the intermediate shaft 29.
The steering center gear 47 meshed with the steering center gear 47 is fixed to the steering clutch shaft 30, and the steering center gear 4
The left and right steering clutches 7 each having a steering gear 7a meshed and connected to the center gear 47 by sliding left and right on the left and right sides of the steering clutch 7, rotate the shaft freely, and the left and right boss portions 7b of the steering clutch 7 A multi-plate type traveling brake 8 to be braked by disengaging the groove 7c and the steering clutch 7 is arranged and configured.

The steering clutch 7 is provided in the left and right shifter grooves 7c.
The left and right shifters 48 for braking the on / off and traveling brakes 8 are fitted, and the left and right shifter shafts 49, on which the shifters 48 are fixed, are projected to the outside of the transmission case 26. Are fixed to each other. Reference numeral 51 denotes a spring for increasing the on-operation force of the steering clutch 7.

Left and right wheel gears 52 meshed with the steering gears 7a of the left and right steering clutches 7 are fixed to one ends of the left and right traveling shafts 31, respectively. The left and right drive wheels 53 are each fixed to the shaft, and the left and right traveling crawlers 10 are drivably stretched by the drive wheels 53, the intermediate rolling wheels 54, and the end rolling wheels 55.

To change the speed of the continuously variable transmission belt 37, a connecting rod 6 is provided between arms 58 and 59 having respective cams 56 and 57 for moving the input and output transmission pulleys 35 and 36 in the axial direction.
0 and the rod 61
The transmission arm 63 and the transmission link 64 are connected to a transmission rotation shaft 62 which is rotatably supported by the transmission case 26, and which is fixed to the outwardly projecting portion of the case 26 of the transmission rotation shaft 62. And the like, and is connected to a main shift lever 65 for switching between forward and backward vehicle speeds and performing a main shift.

The traveling transmission according to the above configuration is performed by the engine 2
4 is transmitted from the engine pulley 66 to the input pulley 33 via the tension clutch pulley 67 and the transmission belt 32, and the main transmission lever 6 is driven by driving the input transmission shaft 27.
5, the speed change operation of both speed change pulleys 35 and 36 is performed.
The rotation speed of the sun gear 42 is changed with respect to the ring gear 40 having a constant rotation in the planetary gear mechanism G to shift the speed from the neutral position to the normal rotation side high speed region or the reverse rotation high speed region.

When the reverse drive from the traveling shaft 31 side or the engine braking is applied as in the case of a downhill, the transmission gear 45 of the planetary gear mechanism G from the traveling shaft 31 side with the steering clutch 7 engaged. And the carrier 44 is driven in reverse, so that even if the planetary gear 41 is revolved by the carrier 44, the ring gear 40 and the sun gear 42 which do not idle via the input speed-change shaft 27, the continuously variable speed-change belt 37, the output speed-change shaft 28 and the like. And the revolution is regulated,
Internal braking is performed and reverse driving is braked.

In particular, the input pulley 3 by the transmission belt 32
When the input clutch 27 is not driven because the tension clutch pulley 67 is disengaged, the continuously variable transmission belt 3 is not driven.
Since the sun gear 7 is not rotated, the sun gear 42 side is not driven even if the sun gear 42 side is reversely driven from the carrier 44.

The power shifted by the planetary gear mechanism G and the continuously variable transmission belt 37 is transmitted from the transmission gear 45 to the intermediate gear 46.
, The power to the steering center gear 47 is transmitted from the steering gear 7a to the wheel gear 52 by the on / off operation of the left and right steering clutches 7 by the shifter 48, and further to the wheel gear 52. To the drive wheels 53 to drive the traveling crawler 10.

The operation of the shifter 48 is such that the shifter arm 50 fixed to the left and right shifter shafts 49 is pressed by the hydraulic operation of the push cylinder 3 by operating the power steering lever 68, and at the same time, the operation of the shifter 48 is performed. Accordingly, the left and right traveling brakes 8 are also braked, so that the steering turning and braking to the left and right sides when the vehicle body 25 travels can be performed.

As shown in FIG. 1, the push cylinder 3 has a pump port P, a tank port T, a boost port R,
A hydraulic switching spool 1 as a hydraulic switching valve 1 for switching an oil passage between the piston operation ports A and B by sliding left and right, and a left and right piston of a clutch piston 4 operated by switching the oil passage by the switching spool 1. The left and right pistons 5A, 5B of the double-acting brake piston 5 loosely fitted in the clutch piston 4 are integrated with the left and right pistons 5A, 5B.

The brake piston 5 is provided with a relief oil passage 6 for leaking pressure oil connecting the pressure receiving surface p and the tank port t at a fixed position.
The power steering lever 68 and the switching spool 1 are connected to a piston cover 3a for holding the clutch piston 4 and operating and stopping the clutch for the disengagement stroke s of the steering clutch 7.
Is slidably connected between the ports P, T, R, A, and B by operating the lever 68. 69 indicates a return spring.

The hydraulic action of the push cylinder 3 is shown in FIG.
When the switching spool 1 is in the neutral position as shown in FIGS.
When the pressure oil from the P port is unloaded through the T port through the B port, for example, when the switching spool 1 is slid toward the right clutch piston 4B, the pressure oil from the P port passes through the B port, The right clutch piston 4B is actuated for the disengagement stroke s of the steering clutch 7 that contacts the piston cover 3a.

The pressure oil that has actuated the right clutch piston 4B for the disengagement stroke s of the steering clutch 7 flows from the notch b of the right clutch piston 4B through the communication hole h, and operates the right brake piston 5B. The right travel brake 8 is braked by the operation of the right brake piston 5B. The braking pressure of the right running brake 8 is controlled by operating the power steering lever 68 so that the switching spool 1 slides and the communication hole h.
And the R port communicate with each other to increase the pressure when the pressure reaches a certain value in proportion to the opening amount of the R port.

When the hydraulic pressure of the right clutch piston 4B is applied, pressure oil flows to the left clutch piston 4A and the left brake piston 5A to cause a leak, and the leak pressure oil is supplied to the pressure receiving surface of the left brake piston 5A. By leaking from p and unloading through the oil passage 6 through the tank port t and the T port, the leak pressure can be reduced.

When the travel brake 8 is braked by the operation of the brake piston 5, the relief oil passage 6 can be closed by the inner wall of the piston cover 3a. The entire pressure can be applied to the braking of No. 8.

In the push cylinder 3 having the above-described structure and operation, as shown in FIG. 3, for example, by changing the outer diameter of the brake piston 5 with respect to the clutch piston 4 to be larger or smaller, the travel brake 8 can be braked. Of the brake piston 5 can be changed to be strong or weak.

As described above, since the braking pressure of the traveling brake 8 can be changed only by changing the outer diameter of the brake piston 5, the base of the push cylinder 3 can be shared in a large or small combine. The cost can be reduced, and in particular, in a small combine or the like, by reducing the diameter of the piston 5, there is an effect that the steering turning and braking to the left and right sides during traveling can be operated with a good feeling.

In the push cylinder 3 having the above construction and operation, as shown in FIGS. 4A and 4B, an arc-shaped portion is provided at the R port of the switching spool 1 for increasing the braking pressure of the traveling brake 8 by the brake piston 5. An aperture with a notch n is provided. In particular, this arc-shaped notch n
By processing the portion with a metal saw so as to have the same arc shape on both sides, it is possible to smoothly pressurize the brake oil of the brake piston 5. (Note that the notch n portion is not necessarily limited to the arc shape.) By providing the switching spool 1 with the arc notch n, the pressure is increased by the usual circular throttle as in the related art. Like the ones, there is no difference in pressure increase between left and right, a sudden change in pressure, and it is difficult to secure initial pressure (constant pressure) at low flow rate from idling to full throttle. As a result, the initial pressure can be secured even at a low flow rate, and a smooth pressure increase line can be obtained by processing the arc-shaped notch n with a metal saw.

In the push cylinder 3 having the above-described structure and operation, a sequence valve 70 is separately provided and a hydraulic circuit is connected as shown in FIG. 5, so that the power steering lever 68 can be tilted. The clutch spool 4 is operated by sliding the switching spool 1.

Further, when the power steering lever 68 is tilted, a pilot pressure acts on the spool 70a of the sequence valve 70, and when this pressure reaches a certain pressure, the spool 70a slides to supply pressure oil. The pressure is blocked at the T port from the port 70b through the discharge port 70c to increase the pressure, and the pressure increases, and the brake piston 5 starts operating.

As described above, since the operation of the clutch piston 4 and the operation of the brake piston 5 can be accurately separated, the steering clutch 7 and the traveling brake 8 are continuously operated as in the conventional case. Thus, when the clutch 7 is disengaged, the braking force also acts on the brake 8, and it is possible to improve the difficulty that the left and right steering during running cannot be smoothly applied.

In the push cylinder 3 having the above construction and operation, as shown in FIG. 6, the switching spool 1 and the pistons 4 and 5 are formed separately from each other. By integrally joining via the O-ring r, problems of processing accuracy and management in the production of the ordinary integrated push cylinder 3 and problems of switching between manual operation and electric operation are solved. can do.

In the push cylinder 3 having the above-described structure and operation, the one clutch piston 4
Is operated, the leak pressure oil flows between the other clutch piston 4 and the brake piston 5, and the piston 5 operates, so that the leak pressure oil escapes to the T port as shown in FIG. A check valve 71 having a configuration different from that of the relief oil passage 6 is provided at the upper end of the clutch piston 4 by a combination of a steel ball 71a, a washer 71b, a retaining ring 71c, and the like.

By providing the check valve 71 on the clutch piston 4 as described above, the pressure oil does not fully act on the brake piston 5 as in the conventional case where a relief hole is provided, so that the braking force is reduced. And the entire pressure can be applied when the brake piston 5 is actuated.

In the push cylinder 3 having the above construction and operation, as shown in FIGS. 8A and 8B, in addition to the switching spool 1 and the pistons 4 and 5, the oil passage is further switched by turning. A rotary spool 72 as a rotary valve is integrally provided, and connected to both sides of the spool 72 so that pressure oil can be supplied from a T port to both sides of the spool 72 so that the spool 72 turns from an unloaded state to a blocked state. Configure.

As described above, by providing the rotary spool 72 integrally with the push cylinder 3, when the spool 72 is rotated and all the T ports are blocked, as shown in the hydraulic circuit of FIG. The brake piston 5 can be operated at the same time. At the time of blocking the T port for rotating the spool 72, the rotating torque can be reduced by the pressure balance applied from both sides of the spool 72, and the hydraulic oil from the P port is supplied to the A and B ports.
By unloading from both ports, pressure loss can be reduced.

[Brief description of the drawings]

FIG. 1 is a plan sectional view showing an integrated configuration of a spool portion and a piston portion of a push cylinder.

FIG. 2A is a plan sectional view showing a state of a push cylinder in a neutral position. FIG. 4B is a plan sectional view showing an operation state of a B-side piston in the push cylinder.

FIG. 3 is a plan sectional view showing a state in which the outer diameter of a brake piston of the push cylinder is changed.

FIG. 4A is a plan sectional view showing a state in which a notch is provided in an R port portion of a push cylinder. (B) Partial view showing the shape of an arc-shaped notch provided in the R port of the switching spool.

FIG. 5 is a block diagram showing a circuit for separating operation between both pistons of a push cylinder.

FIG. 6 is a cross-sectional plan view showing a state in which a spool portion and a piston portion of the push cylinder are formed separately.

FIG. 7 is a partial cross-sectional view showing a check ring provided on a clutch piston of a push cylinder.

FIG. 8A is a cross-sectional plan view showing an integrated configuration of a rotary valve and a push cylinder. (B) A sectional side view showing a state in which the rotary valve is integrated with the push cylinder.

FIG. 9 is a block diagram showing a hydraulic circuit when the rotary valve is integrally formed.

FIG. 10 is a front development view showing a transmission mechanism using gears and a belt of the traveling transmission case.

FIG. 11 is a side view showing a transmission mechanism portion using a belt of the traveling transmission case.

FIG. 12 is a side view showing the overall configuration of the combine.

[Explanation of symbols]

 1. Switching valve 3. Push cylinder 4. Clutch piston 5. Brake piston 6. 6. Escape oil passage Steering clutch 8. Travel brake p. Pressure receiving surface t. Tank port s. Cutting stroke

Claims (2)

[Claims] 1. A clutch having a clutch piston (4) operated by pressure oil sent to a push cylinder (3) by switching a hydraulic switching valve (1) and a double-acting brake piston (5) loosely fitted in the clutch piston (4). ,
The brake piston 5 is provided with a relief oil passage 6 for leak pressure oil that connects between the pressure receiving surface p and a tank port t for returning to the oil tank, and the clutch piston 4 operates the steering stroke 7 of the steering clutch 7. A push-cylinder device for a traveling vehicle or the like, wherein the escape oil passage 6 is closed when the vehicle is driven. 2. A steering clutch, comprising: a clutch;
After the cutting stroke s is operated, the traveling brake 8 is further successively operated by the double action of only the brake piston 5.
2. The push cylinder device according to claim 1, wherein the thrust during the braking operation is changeable by changing the outer diameter of the brake piston.