JP3599508B2 - Traveling gear for work vehicles - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a traveling transmission device for a working vehicle such as a combine, and more specifically, is configured to transmit power to the traveling device via a hydraulic traveling clutch that reversibly switches to a transmission state in response to supply of pressure oil. Further, the present invention relates to a device provided with a switching valve operable to switch between a transmission state in which pressure oil is supplied to the traveling clutch and a non-transmission state in which the pressure oil is released in a pressure oil supply path to the traveling clutch.
[0002]
[Prior art]
As a traveling transmission of a combine, which is an example of a traveling transmission of a work vehicle of this type, as disclosed in JP-A- 8-20250, a forward clutch and a reverse clutch are provided as traveling clutches, A switching valve is provided that can be operated to switch between a forward transmission state in which pressure oil is supplied to the forward clutch, a reverse transmission state in which pressure oil is supplied to the reverse clutch, and a non-transmission state in which pressure oil is released. The power is transmitted to the reaper via a hydraulic work clutch which reversibly switches to a transmission state in accordance with oil supply, and the switching of the pressure oil supply path to the forward clutch and the reverse clutch is performed. A device is known in which the work clutch is connected upstream of a valve.
When the switching valve is operated to switch to a forward transmission state or a reverse transmission state and the forward clutch or the reverse clutch is switched to the transmission state by supplying hydraulic oil, this device supplies the working clutch with hydraulic oil, so to speak. By making this work clutch also function as an accumulator, the hydraulic shock acting on the forward clutch and the reverse clutch is reduced, and the forward clutch and the reverse clutch can be smoothly switched to the forward transmission state and the reverse transmission state. It was intended to be able to do it.
[0003]
[Problems to be solved by the invention]
However, according to the above-described conventional technique, the amount of oil required when the work clutch is switched to the transmission state is very small. Therefore, when the switching valve is switched to the forward transmission state or the reverse transmission state, the forward clutch And the pressure oil supplied to the reverse clutch rises to a predetermined value in a very short time, and the hydraulic shock cannot be sufficiently reduced.
[0004]
SUMMARY OF THE INVENTION It is an object of the present invention to sufficiently reduce a hydraulic shock acting on a traveling clutch when a switching valve is switched to a transmission state.
[0005]
[Means for Solving the Problems]
The features, functions and effects of the present invention according to claim 1 are as follows.
[0006]
〔Characteristic〕
Power is transmitted to the traveling device via a traveling clutch for switching between forward and backward, which is composed of a hydraulic forward traveling clutch and a reverse traveling clutch that reversibly switch to a transmission state in response to the supply of pressure oil. Then, it is operable to switch between a transmission state in which pressure oil is supplied to the forward travel clutch or the reverse travel clutch in the pressure oil supply path to the forward travel clutch and the reverse travel clutch, and a non-transmission state in which the pressure oil is released. A traveling transmission device for a working vehicle provided with a switching valve, wherein a traveling brake provided on a transmission path from the forward traveling clutch and the reverse traveling clutch to the traveling device is released from a brake state with a supply of pressure oil. the hydraulic actuator for switching operation against the biasing force of the state of the spring connected to the pressure oil supply passage, the switching valve or the non-transmission state Together configured to accumulate a part of the hydraulic fluid supplied to the forward running clutch or backward traveling clutch to the hydraulic actuator by compressing the spring with the switching to the transmission state, to the hydraulic actuator Is provided with a throttle in the branch supply path.
[0007]
[Action]
According to the present invention, the travel brake is brought into the brake release state by supplying hydraulic oil to the hydraulic actuator, and the travel brake is brought into the brake state by the biasing force of the spring due to the escape of the hydraulic oil from the hydraulic actuator. Sometimes, one of the forward traveling clutch and the reverse traveling clutch as the traveling clutch that switches between forward and backward is switched to the transmission state, the traveling brake is set to the brake release state, and the hydraulic actuator is Focusing on the point that sufficient hydraulic oil is required to function as a hydraulic actuator, switching the hydraulic actuator to the hydraulic oil supply path to the forward running clutch or the reverse running clutch and switching the valve to the transmission state Connect so that pressure oil is supplied, and switch the switching valve to the transmission state. Actuator when replaced, since the pressure oil to the forward running clutch and reverse traveling clutch and the hydraulic actuator are so as to divert supply, the hydraulic actuator to the brake release state against a traveling brake biasing force In addition to functioning as a part, a part of the hydraulic oil supplied to the forward or reverse travel clutch is accumulated to prevent all hydraulic oil from being suddenly supplied to the forward travel clutch or the reverse travel clutch. It works well as an accumulator.
[0008]
In addition, there is a means for releasing the hydraulic oil from the hydraulic actuator by stopping the engine and stopping the hydraulic pump as a means for putting the traveling brake into a braking state by the urging force. Otherwise, the driving brake does not enter the braking state.
On the other hand, according to the present invention, the hydraulic oil is released from the hydraulic actuator in accordance with the switching of the switching valve to the non-transmission state, so that the traveling is stopped by stopping the traveling without stopping the engine. Brake can be put in the brake state.
[0009]
In addition, a throttle is provided to provide resistance to the escape of hydraulic oil from the hydraulic actuator by the spring when the switching valve is switched to the non-transmission state so that the forward traveling clutch and the reverse traveling clutch are switched to the non-transmission state. As a result, the switching of the traveling brake from the brake release state to the brake state can be performed at a slow speed, and the hydraulic oil is suddenly returned from the hydraulic actuator to the hydraulic oil supply path. The rise of the pressure oil in the pressure oil supply path, that is, the operation of the traveling clutch to the transmission side can be prevented.
[0010]
〔effect〕
Therefore, according to the present invention, the hydraulic shock when switching the switching valve to the transmission state and switching the forward traveling clutch or the reverse traveling clutch to the transmission state can be sufficiently reduced, and the forward traveling clutch or the reverse traveling clutch can be sufficiently reduced. When the traveling is stopped by switching the switching valve to the non-transmission state and switching the forward traveling clutch and the reverse traveling clutch to the non-transmission state, the switching to the transmission state can be performed very smoothly. Can release the hydraulic oil from the hydraulic actuator and switch the traveling brake to the braking state with the biasing force of the spring, and reliably stop the vehicle on a slope such as a slope, even while the engine is running, and When traveling with the switching valve switched to the transmission state, the traveling brake is switched to the brake released state and the traveling is good. Can be done, moreover, with the sudden braking when switching the switching valve to the non-transmission state can be prevented, so that the forward traveling clutch or backward traveling clutch can be prevented clutch defective to be a half-clutch became.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
As shown in FIG. 2, a traveling power transmission of a combine, which is an example of a work vehicle, receives power from an engine 2 through a belt transmission 1 provided with a tension clutch (not shown). And the output power of the belt-type continuously variable transmission 3 is transmitted to a pair of left and right crawler traveling devices 6 via a transmission mechanism in a transmission case 5.
[0012]
The transmission mechanism includes an input shaft 8 interlocked with an output shaft 7 of the belt-type continuously variable transmission 3 via a spline so as to rotate integrally with the output shaft 7, a first gear 9 and a first gear 9 connected to the input shaft 8. An intermediate shaft 11 interlocked with the second gear 10, a third gear 12 interlocked with the second gear 10, and a forward transmission shaft 14 interlocked with the intermediate shaft 11 via a hydraulic forward clutch 13; A fourth transmission gear 15 interlocked with the third gear 12 and a reverse transmission shaft 17 interlocked with the intermediate shaft 11 via a hydraulic reverse clutch 16; the forward transmission shaft 14 and the reverse transmission shaft; 17 is provided with a gear-type auxiliary transmission 18 that is gear-coupled to a gear, and a pair of left and right steering clutches / brakes 20 that respectively link left and right axles 19 of the crawler traveling device 6 with the auxiliary transmission 18. Configuration It has been.
[0013]
The third gear 12 is rotatably held by a forward drive shaft 14, and the fourth gear 15 is rotatably held by a reverse drive shaft 17.
[0014]
The forward traveling clutch 13 is switched to a transmission state in which the forward transmission shaft 14 is interlocked with the third gear 12 with the supply of the pressure oil, and the forward transmission shaft 14 is interlocked with the third gear 12 as the pressure oil escapes. The reverse traveling clutch 16 is switched to a transmission state in which the reverse transmission shaft 17 is interlocked with the fourth gear 15 in response to the supply of the pressure oil, and the reverse travel clutch 16 is switched to the non-transmission state in which the pressure oil is released. The driving clutch C is switched to a non-transmission state in which the reverse transmission shaft 17 is not interlocked with the four gears 15, and these are the traveling clutch C described in the claims.
[0015]
As shown in FIG. 3, the clutch / brake 20 includes a clutch portion 20A and a brake portion 20B. The clutch / brake 20 is brought into a transmission state by a series of shift operations against a spring 22 via a shifter 21. A transmission mode in which the brake unit 20B is in the brake release state, a non-transmission mode in which the clutch unit 20A is in the non-transmission state, and a non-transmission mode in which the brake unit 20B is in the brake release state, and the clutch unit 20A is in the non-transmission state. At the same time, it can be switched to a brake mode in which the brake unit 20B is brought into a brake state.
[0016]
Therefore,
The forward traveling clutch 13 is switched to the transmission state, and both the left and right clutches and brakes 20 are switched to the transmission mode, so that the power from the input shaft 8 is transmitted to both crawler traveling devices 6 as the forward power, so that the forward traveling is performed. Go straight ahead,
The reverse traveling clutch 16 is switched to the transmission state, and both the left and right clutches and brakes 20 are switched to the transmission mode, so that the power from the input shaft 8 is transmitted to the two crawler traveling units 6 as the reverse power, thereby allowing the reverse traveling. Go straight ahead,
By switching the forward running clutch 13 to the transmission state and switching one of the left and right clutches / brake 20 to the transmission mode and the other to the non-transmission mode, the power from the input shaft 8 is used as the forward power. By transmitting to only one crawler traveling device 6, a forward gentle turning is performed with the other turning inside,
By switching the reverse traveling clutch 16 to the transmission state, switching one of the left and right clutches and brakes 20 to the transmission mode and switching the other to the non-transmission mode, the power from the input shaft 8 is used as the reverse power. By transmitting only to one of the crawler traveling devices 6, the vehicle performs a slow reverse turning with the other turning inside,
By switching the forward running clutch 13 to the transmission state, switching one of the left and right clutches and brakes 20 to the transmission mode and switching the other to the brake mode, the power from the input shaft 8 is used as the forward power. Of the other crawler traveling device 6 and, by applying a brake to the other crawler traveling device 6, perform a rapid forward turn with the other turning inside,
The reverse drive clutch 16 is switched to the transmission state, one of the left and right clutches / brakes 20 is switched to the transmission mode, and the other is switched to the brake mode, so that the power from the input shaft 8 is used as the reverse power. And the other crawler traveling device 6 is braked so that the other crawler traveling device 6 performs reverse rapid turning with the other turning inside.
[0017]
Further, one clutch / brake 20 is provided with a brake arm 24 for switching the brake unit 20B between a brake state and a brake release state via a cam 23.
[0018]
Then, by switching the brake portion 20B of one clutch / brake 20 to the brake state while the left and right clutch / brakes 20 are switched to the transmission mode, the left and right crawler traveling devices 6 are braked. I have. That is, the traveling brake B is the brake unit 20B that can be switched between the brake state and the brake release state by operating the brake arm 24.
[0019]
A cutting output shaft 25 for transmitting power via a belt transmission to a cutting pre-processing unit (not shown) at the front of the combine body is disposed above the transmission case 5. A fifth gear 26 attached to the cutting output shaft 25 so as to rotate integrally with the intermediate shaft 11, and a sixth gear 27 rotatably held by the cutting output shaft 25 in a state in which the fifth gear 26 meshes with and is interlocked with the fifth gear 26. The input power is transmitted through a hydraulic work clutch 28.
[0020]
As shown in FIG. 3, the operating means for the forward running clutch 13 and the reverse running clutch 16 is connected to the hydraulic oil supply passage 30 from the hydraulic pump 29 to the forward running clutch 13 and the reverse running clutch 16. A switching valve 31 that can be switched between a forward transmission state in which pressure oil is supplied only to the clutch 13, a reverse transmission state in which pressure oil is supplied only to the reverse traveling clutch 16, and a neutral state in which pressure oil is released. A forward / reverse switching operation lever 32 for switching the switching valve 31 is provided. By operating the forward / backward switching operation lever 32 to the forward position F, the switching valve 31 is switched to the forward transmission state and operated to the reverse position R. The switching valve 32 is switched to the reverse transmission state, and the switching valve 32 is switched to the neutral state by operating to the neutral position N. It is configured so that.
[0021]
As shown in FIGS. 3 and 4, the operating means for the clutch / brake 20 extends the shifter 21 against the urging force of the return spring 33 in accordance with the supply of the pressure oil, thereby shifting the shifter 21 to the transmission mode position / non-transmission state. The shifter 21 is operated in the order of the description in the mode position and the brake mode position, and the shifter 21 is shortened by the urging force as the pressurized oil escapes, thereby reducing the shifter 21 in the brake mode position, the non-transmission mode position, and the transmission mode position. The hydraulic cylinder 34 is provided with a take-out oil passage 36 for supplying the excess flow taken from the pressure oil supply passage 30 through the flow dividing valve 35 to the hydraulic cylinder 34 as hydraulic oil. A steering lever 37 operable at a turning position L1, a sharp left turning position L2, a gentle gentle turning position R1, and a sharp right turning position R2 is provided. A control valve 38 interlocked with the steering lever 37 to control the hydraulic cylinder 34 according to the operating position of the 37, and the pressure of the hydraulic oil supplied to the hydraulic cylinder 34 is adjusted according to the operating position of the steering lever 37. And a pressure adjusting valve 39 interlocked with the steering lever 37.
[0022]
When the steering lever 37 is located at the straight-ahead position S, the control valve 38 allows the left and right shifters 21 to be both at the transmission mode position to release the pressurized oil and shorten the two left and right hydraulic cylinders 34 to perform a straight-ahead movement. When the steering lever 37 is located at the gentle left turning position L1 and the sharp left turning position L2, the left turning state in which the hydraulic cylinder 34 corresponding to the left clutch / brake 20 supplies the hydraulic oil so as to extend. When the steering lever 37 is located at the gentle right turning position R1 and the sharp right turning position R2, a right turning state in which the hydraulic cylinder 34 corresponding to the right clutch / brake 20 supplies the hydraulic oil so as to extend. It switches to and.
[0023]
When the steering lever 37 is located at the gentle left turning position L1 and the gentle right turning position R1, the pressure adjusting valve 39 disengages the shifter 21 against the urging force of the return spring 33 and the spring 22. When the steering lever 37 is positioned at the sharp left turning position L2 and the sharp right turning position R2, the hydraulic cylinder The pressure is adjusted to the pressure of the hydraulic oil supplied to the hydraulic cylinder 34 so that the shifter 21 is in an extended state in which the shifter 21 is positioned at the brake mode position against the urging force of the return spring 33 and the spring 22.
[0024]
As shown in FIGS. 1 and 3 to 6, the operating means for the travel brake B is provided with a compression spring 42 for pulling the brake arm 24 of the travel brake B to the brake position via the wire 40, The hydraulic cylinder 43 (an example of a hydraulic actuator) that allows the compression spring 42 to extend to release the tensile force by being shortened with the supply and to allow the compression spring 42 to return elastically as the pressure oil escapes, A return spring 44 is provided so as to be connected to a portion of the supply path 30 upstream of the switching valve 31 and operates the brake arm 24 to the brake release position when the pulling force is released.
That is, by switching the switching valve 31 between the forward transmission state and the reverse transmission state, the hydraulic oil is supplied to the hydraulic cylinder 43, the traveling brake B is released, and the hydraulic cylinder is switched by switching the switching valve 31 to the neutral state. The travel brake B is brought into a brake state by releasing the pressure oil in the 43 and elastically returning the compression spring 42 to the extended state.
[0025]
A throttle 51 is provided in a branch supply path 30A from the pressure oil supply path 30 to the hydraulic cylinder 43. In other words, the throttle 51 applies resistance to the escape of the hydraulic oil from the hydraulic cylinder 43 by the compression spring 42 when the switching valve 31 is switched to the neutral state, and the traveling brake B is switched from the brake released state to the brake state. The switching speed is reduced, and the rise of the pressure oil in the pressure oil supply path 30 due to the return of the pressure oil from the hydraulic cylinder 43 to the pressure oil supply path 30 is prevented.
[0026]
The means for providing the throttle 51 is a means for screwing a plug 52 having the throttle 51 formed in the pressure oil supply path 30 into a supply path forming member 53 as shown in FIG.
[0027]
Therefore, according to the above configuration, the hydraulic oil is shunted and supplied to the hydraulic cylinder 43 by the forward transmission state and the reverse transmission state of the switching valve 31, so that the hydraulic cylinder 43 acts as an accumulator, as shown in FIG. As shown, the hydraulic shock acting on the forward traveling clutch 13 and the reverse traveling 16 is reduced, and the rise of the pressure oil supplied to the forward traveling clutch 13 and the reverse traveling clutch 16 can be made gentle.
[0028]
As shown in FIGS. 1 and 6, the operating means for the traveling brake B is a brake pedal for depressing the traveling brake B to bring the traveling brake B into a braking state stronger than the braking state by the compression spring 42. 45.
The linking means between the brake pedal 45 and the traveling brake B is provided with an interlocking rod 46 for linking the brake pedal 45 and the brake arm 24 so that the brake arm 24 is moved to the brake position by depressing the brake pedal 45. It is configured.
The interlocking rod 46 is engaged and interlocked with the brake arm 24 via the pin 47, and is interlocked with the pin 47 of the interlocking rod 46 as shown in FIGS. The hole 48 is formed as a long hole which allows the brake arm 24 to operate from the brake release position to the brake position by pulling through the wire 40 in a state where the brake pedal 45 is located at the brake release return position. I have.
[0029]
The brake pedal 45 is provided with an operation lever 49 for manually operating the brake pedal 45. The operation lever 49 is engaged with the holding portion 50 when the brake pedal 45 is depressed and the brake is applied. It is detachable and also serves as a brake lock device that holds the brake pedal 45 in the brake state by engaging.
[0030]
As shown in FIG. 3, the work clutch 28 is connected to the upstream side of the switching valve 31 in the pressure oil supply path 30 similarly to the hydraulic cylinder 34, and the switching valve 31 is in the forward transmission state and the reverse transmission state. , The pressure oil is supplied to switch to the transmission state, and the switching valve 31 is switched to the neutral state to release the pressure oil and switch to the non-transmission state.
The reference numeral 52 indicates that the hydraulic pressure in the pressure oil supply passage 30 is maintained at a set value even when the switching valve 31 is in the neutral state, and the hydraulic pressure in the forward traveling clutch 13, the reverse traveling clutch 16, and the work clutch 28 is maintained. The set value is a low pressure that does not operate the forward running clutch 13, the reverse running clutch 16, the work clutch 28, and the hydraulic cylinder 34. is there.
[Brief description of the drawings]
1 is a cutaway side view of a transmission case [FIG. 2] a transmission system diagram [FIG. 3] a hydraulic circuit diagram [FIG. 4] a front view of the transmission case [FIG. 5] a cross-sectional view showing a hydraulic cylinder portion of the transmission case FIG. 6 is a side view showing a brake operation system. FIG. 7 is an explanatory view of a brake operation. FIG. 8 is a graph showing a rising state of pressure oil acting on a traveling clutch.
B Running brake C Running clutch 6 Running device 30 Pressure oil supply path 31 Switching valve 42 Spring 43 Hydraulic actuator 30A Branch supply path 51 Throttle

Claims (1)

The vehicle travels via a forward / reverse switching travel clutch (C) including a hydraulic forward travel clutch (C) and a reverse travel clutch (C) that reversibly switch to a transmission state in response to the supply of pressure oil. The power transmission device (6) is configured to transmit power to the forward traveling clutch (C) or the reverse traveling through a pressure oil supply path (30) to the forward traveling clutch (C) and the reverse traveling clutch (C). A traveling transmission device for a working vehicle provided with a switching valve (31) operable to switch between a transmission state in which pressure oil is supplied to a clutch (C) and a non-transmission state in which pressure oil is released, wherein The traveling brake (B) provided on the transmission path from the clutch (C) and the reverse traveling clutch (C) to the traveling device (6) is applied by a spring (42) from the brake state to the brake release state with the supply of pressure oil. Against the power Connect the hydraulic actuator (43) for switching operation to the pressure oil supply passage (30), and the switching valve (31) is compressing the spring (42) with the switch from the non-transmission state to the transmission state the The hydraulic actuator (43) is configured to accumulate a part of the pressure oil supplied to the forward travel clutch (C) or the reverse travel clutch (C) . A traveling power transmission for a working vehicle having a throttle (51) provided in a branch supply path (30).

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