JPH0659800B2 - Hydraulic clutch device for traveling of work vehicle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention is directed to a traveling hydraulic clutch device for a working vehicle configured to be capable of forward / backward switching operation so that forward / backward switching operation is performed with less shock. Regarding technology.

[Conventional technology]

An example of the structure of the forward / reverse switching operation as described above is disclosed in JP-A-62-62.
-39335 publication.

This structure is equipped with one clutch and a gear switching type forward / reverse switching device.For example, when an operation signal to the reverse side is input during forward movement, the forward / reverse switching device is not immediately operated to the reverse side. First, while the forward / reverse switching device is left on the forward side, the traveling transmission is shifted to the low speed side, and the forward speed of the vehicle body is decelerated by the action of the engine brake.

When the forward speed of the vehicle body is sufficiently reduced, at this time, the clutch is disengaged once to operate the forward / reverse switching device to the reverse side, and the clutch is operated to the engaged state side again. In this case, the reverse acceleration is detected, and the clutch engagement operation force is controlled to be strong or weak so that the reverse acceleration is maintained at the set value.

[Problems to be Solved by the Invention]

In the above configuration, when starting the control of the clutch operating force that keeps the reverse acceleration at the set value,
After the forward speed of the vehicle body is decelerated by the action of the engine brake to sufficiently reduce the forward speed of the machine body, the control of the engaging force for the reverse clutch is started.

In this way, even if the aforementioned control is started after the forward speed of the vehicle body has been sufficiently reduced, the vehicle body is still moving forward. When the vehicle is operated to the reverse side and the clutch is operated to the engaged state so that the reverse acceleration is maintained at the set value, the vehicle body suddenly starts reverse in the forward state and the reverse speed is accelerated, resulting in shock. Will occur.

SUMMARY OF THE INVENTION It is an object of the present invention to reduce a shock during a forward / reverse switching operation in a traveling hydraulic clutch device for a work vehicle configured to allow forward / reverse switching operation.

[Means for Solving the Problems]

A feature of the present invention is that the traveling hydraulic clutch device for a working vehicle, which is configured to be capable of switching between forward and backward movement, is configured as follows.

A friction type forward hydraulic clutch and a reverse hydraulic clutch, a valve mechanism for adjusting the pressure of the hydraulic oil supplied to the hydraulic clutch, and a lower side hydraulic clutch for the forward and reverse hydraulic clutches in the traveling system. A measuring means for detecting acceleration is provided, and one hydraulic clutch is operated from the engaged state to the disengaged state,
During forward / reverse switching operation in which hydraulic oil is supplied to the other hydraulic clutch to operate the hydraulic clutch, the acceleration detected by the measuring means changes from the direction of the hydraulic clutch on one side to the direction of the hydraulic clutch on the other side. When the specified value of the direction of the hydraulic clutch on the other side is reached, the hydraulic oil at the pressure when the specified value is reached is supplied to the hydraulic clutch on the other side for the set time, and the set time A control means for operating the valve mechanism is provided so that, when the time has elapsed, the pressure of the hydraulic oil is increased from the pressure when the predetermined value is reached and the hydraulic clutch on the other side is engaged.

[Action]

(I) When configured as in the present invention, as shown in, for example, FIGS. 4 (a), (b), and (c), when switching to the reverse side during forward movement,
The hydraulic oil is removed from the forward hydraulic clutch in the engaged state and is operated in the disengaged state, and the hydraulic oil is supplied to the reverse hydraulic clutch to operate in the engaged state.

In this case, the vehicle body is still moving forward due to inertial force,
In the initial period when the reverse hydraulic clutch is operated to the engaged state, the power from the reverse hydraulic clutch is consumed for decelerating the forward speed, which reduces the forward speed of the vehicle body. To go. Then, the forward speed is further reduced, the vehicle body stops, and the vehicle body starts to move backward (during this time, hydraulic oil is supplied to the hydraulic clutch for backward movement and this is operated toward the engaged state) When the acceleration of 1 reaches a predetermined value (β), the pressure of the hydraulic oil to the reverse hydraulic clutch is maintained at the pressure at that time.

(Ii) When the vehicle body actually starts moving backward from the forward state,
By stopping and holding the operation for increasing the pressure of the hydraulic oil to the reverse hydraulic clutch, it is possible to suppress a situation in which the vehicle body suddenly starts reverse and the reverse speed is accelerated in the forward condition.

Then, the state of holding the pressure of the hydraulic oil is continued for a set time, and when the set time elapses, the pressure of the hydraulic oil is increased to put the hydraulic clutch for reverse drive into the engaged state.

(Iii) Japanese Unexamined Patent Publication No. 62-39335 disclosed in the above [Prior Art]
When the clutch engagement operation force is controlled so that the acceleration of the vehicle body becomes constant as in the structure of Japanese Patent Publication, when the front-back posture of the vehicle body is likely to change, such as when traveling on an uneven terrain,
When the vehicle is in the half-clutch state during the forward / reverse switching operation, the change in the front-rear posture of the vehicle body is fed back to the clutch as the change in the vehicle body acceleration. A shock may occur, or the time it takes to engage the clutch may become longer.

On the other hand, in the present invention, for example, when the vehicle body actually starts to move backward from the forward movement state, the pressure of the hydraulic oil to the hydraulic clutch for backward movement is maintained at the pressure at that time. Therefore, even if the reverse acceleration changes, the pressure of the hydraulic oil to the reverse hydraulic clutch does not pulsate and a shock does not occur.

〔The invention's effect〕

As described above, during forward / reverse switching operation, when the vehicle body actually starts moving backward from the forward movement state (or starts moving forward from the backward movement state), the hydraulic oil to the backward movement hydraulic clutch (or forward movement hydraulic clutch) By maintaining the pressure of, it is possible to suppress the state where the vehicle body is suddenly accelerated, and it is possible to suppress the shock at the time of the forward / reverse switching operation and improve the riding comfort of the work vehicle.

Further, even when the forward / reverse switching operation is performed on an uneven terrain, the forward / backward switching operation can be performed with less shock regardless of the change in the forward / backward posture of the vehicle body, and the riding comfort of the work vehicle can be further improved.

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 2, a traveling clutch (2) to which power from the engine (1) is transmitted and an external clutch (3) are provided, and the power from the traveling clutch (2) is a tubular shape for the traveling system. The power from the external clutch (3) is transmitted to the input shaft (4), and is transmitted to the transmission shaft (6) fitted inside the input shaft (4) for driving the external power shaft (5). The clutch case (8) is externally fitted and fixed to the input shaft (4) via the key (7), and the output gear (9) is externally fitted to the input shaft (4) so as to be coaxial with the input shaft (4). The input gear (11) is fixed to the cylindrical intermediate shaft (10) arranged.

Idle gear (12) between output gear (9) and input gear (11)
And a reverse gear transmission system composed of two gears (13) and (14) is formed, and the reverse gear transmission system for transmitting the power from the input shaft (4) to the output gear (9) is transmitted to the clutch case (8). Hydraulic clutch
(C ₁ ) and a forward hydraulic clutch (C ₂ ) for directly transmitting the power from the input shaft (4) to the input gear (11) are housed. The reverse and forward hydraulic clutches (C ₁ ) and (C ₂ ) are equipped with a number of friction plates (15) and (16) and hydraulic pistons (17) and (18) to supply hydraulic oil. It is configured so that it can be operated in a closed state.

Power from the intermediate shaft (10) is passed through the transmission (19) to the wheels (20).
The traveling system is formed in such a way that it can be transmitted to. This traveling system is configured to be equipped with an agricultural tractor, and the transmission system of this traveling system generates shock as much as possible when shifting due to the operation of the hydraulic clutches (C ₁ ) and (C ₂ ) for reverse and forward movement. A control system for controlling the pressure of the hydraulic oil to the reverse and forward hydraulic clutches (C ₁ ) and (C ₂ ) is provided so as not to allow the reverse movement.

Next, this control system will be described. As shown in FIG. 1, hydraulic fluid from the hydraulic pump (21) is sent to the forward / reverse switching valve (22), and the forward / reverse switching valve (22) is used to reverse and forward hydraulic clutches (C ₁ ), ( Electromagnetic proportional pressure reducing valves (V ₁ ), (V ₂ ) (corresponding to a valve mechanism) are provided in each of the oil passages (23), (24) for sending the hydraulic oil to C ₂ ). The electromagnetic proportional pressure reducing valves (V ₁ ) and (V ₂ ) are operated by an operation signal from a control device (25) incorporating a microprocessor (not shown), and the control device (25) operates the forward / reverse switching valve (22 ) Switch (26) to detect the operating position, a sensor (S) that detects the acceleration of the traveling system from the rotation of the wheels (20) (reverse and forward hydraulic clutches (C ₁ ), (C ₂ ) Corresponding to a measuring means for detecting the acceleration on the lower side) is inputted. The control device (25) has a program set so as to operate according to the flowchart of FIG. 3, and this program follows the switching operation of the reverse and forward hydraulic clutches (C ₁ ) and (C ₂ ). A control means (T) for increasing the clutch internal pressure with predetermined characteristics is formed.

Next, based on the flowchart of FIG. 3, the control device (25)
The operation of will be described.

For example, when advancing a stopped aircraft, it is determined that the changeover switch (26) has been operated to the forward side (# 1 step), and the forward hydraulic clutch (C ₂ ) has time (T ₁ ) Supply a large amount of hydraulic oil, and then move forward to the hydraulic clutch (C
Increase the hydraulic oil pressure to ₂ ) at a predetermined ratio (# 2
# 3 step).

This operation is performed as shown in Fig. 4 (a).
Performed by changing the current value with respect to (V ₂ ), and the electromagnetic proportional pressure reducing valve (V ₂ )
Is configured to increase / decrease the pressure of hydraulic oil in response to increase / decrease in current value. As described above, the reason for supplying a large amount of hydraulic oil is the hydraulic clutch that is operated in the on state.
By narrowing the gap between the friction plates (15) and (16) of (C ₁ ) and (C ₂ ) in advance, the time required to operate the hydraulic clutches (C ₁ ) and (C ₂ ) into the engaged state can be reduced. This is to shorten it.

Next, as shown in FIGS. 4 (a), (b), and (c), the forward acceleration (X) of the vehicle body is input based on the signal from the sensor (S) to set a predetermined value (α). By comparing the forward acceleration (X) with the forward acceleration (Steps # 4 and # 5), whether the forward hydraulic clutch (C ₂ ) has reached the half-clutch state and the forward speed (vehicle body speed) has started to be accelerated. To determine. # 4, # 5
When the acceleration of the forward speed is recognized in the step, the operation for increasing the pressure of the hydraulic oil is stopped (# 6 step), and while the half-clutch state of the hydraulic clutch (C ₂ ) for the forward is continued, the time set in the timer ( The forward speed is accelerated only during (T ₂ ).
(7, # 8 step), and thereafter, the pressure of the hydraulic oil is increased to the maximum value to operate the forward hydraulic clutch (C ₂ ) to the completely engaged state (# 9 step).

After starting the forward movement as described above, the changeover switch (2
When (6) is operated to the reverse side (# 10 step), drain the hydraulic oil from the forward hydraulic clutch (C ₂ ) in the engaged state and operate it in the disengaged state (# 11 step), then Similar to the 2 step, a large amount of hydraulic oil is supplied to the reverse hydraulic clutch (C ₁ ) for the time (T ₁ ) (# 12 step), and then the reverse hydraulic clutch (C ₁ ) To hydraulic fluid (# 13 step).

In this way, when the changeover switch (26) is switched from the forward side to the reverse side, the vehicle body is still moving forward due to inertial force, so that the reverse hydraulic clutch (C ₁ ) reaches the initial half-clutch state. Considering that power is consumed for decelerating the forward speed,
It is set lower than the step increase rate.

Next, as shown in FIGS. 4 (a), (b) and (c), when the hydraulic oil is supplied to the reverse hydraulic clutch (C ₁ ) with a predetermined pressure characteristic, the sensor (S) Input the backward acceleration (X) of the vehicle based on the signal and set a predetermined value (β)
By comparing the reverse acceleration (X) with (# 14, # 1
(5 steps), it is determined whether the reverse hydraulic clutch (C ₁ ) reaches the half-clutch state, the vehicle body actually starts to move backward, and the reverse speed (vehicle body speed) actually starts to accelerate (# 14, # 15 steps).

In this case, since the reverse hydraulic power (C ₁ ) reaches the half-clutch state, the backward power is consumed for decelerating the forward speed in the initial stage, so the acceleration (X) in a relatively low state is detected. However, it can be inferred that a certain amount of time has passed since the reverse hydraulic clutch (C ₁ ) reached the half-clutch state. Thus, by setting the predetermined value (β) appropriately lower than the above-mentioned predetermined value (α), it is possible to detect the half-clutch state when the vehicle body in the stopped state is started.

When the reverse speed acceleration is recognized in steps # 14 and # 15, the operation of increasing the hydraulic oil pressure is stopped (step # 16), and the half-clutch state of the reverse hydraulic clutch (C ₁ ) is continued, The reverse speed is accelerated only during the time (T ₃ ) set in the timer (corresponding to the set time) (steps # 17 and # 18), after which the hydraulic oil pressure is increased to the maximum value for reverse. Operate the hydraulic clutch (C ₁ ) on to the fully engaged state. In this case, steps # 13 to # 19 are referred to as control means (T).

The above operation is performed by setting the current value of the operation signal to the electromagnetic proportional pressure reducing valves (V ₁ ) and (V ₂ ), the vehicle speed as the absolute value of the forward speed and the reverse speed, and the forward and reverse accelerations (X) of the vehicle. When expressed in a graph, it is drawn as shown in Fig. 4 (a) (b) (c). The sensor (S) is configured to detect the rotation of the gear (27) attached to the drive shaft (20a) of the wheel (20) by the pickup type coil (28).

[Another embodiment]

The present invention may be applied to, for example, a multi-stage speed change system other than the above-described embodiments, and may be provided in a face shovel, a forklift, or the like. Further, the control means (T) may be configured by hardware by combining a comparator, a logic gate and the like. The measuring means (S) can be configured in various ways such as an optical sensor type and a power generation type, and the valve mechanisms (V ₁ ) and (V ₂ ) can be variously implemented in addition to the electromagnetic proportional pressure reducing valve.

It should be noted that reference numerals are added to the claims for convenience of comparison with the drawings, but the present invention is not limited to the configurations of the accompanying drawings by the entry.

[Brief description of drawings]

The drawings show an embodiment of a hydraulic clutch device for traveling of a work vehicle according to the present invention. Fig. 1 is a block diagram of a control system, Fig. 2 is a schematic diagram of a transmission system, and Fig. 3 shows an operation of the control device. A flow chart, Fig. 4 (a) is a graph of the current value to the electromagnetic proportional pressure reducing valve at the start of forward movement and at the time of switching operation from forward to reverse, and Table 4 (b) is at the start of forward and switching from forward to reverse. FIG. 4 (c) is a graph showing the vehicle speed at the time of operation, and FIG. 4 (c) is a graph showing the acceleration of the vehicle at the time of starting forward movement and at the time of switching operation from forward to reverse. (C ₁ ), (C ₂ ) …… hydraulic clutch, (S) …… measuring means, (T)…
… Control means, (V ₁ ), (V ₂ ) …… Valve mechanism, (X) …… Acceleration,
(Β) …… predetermined value, (T ₃ ) …… set time.

Claims (1)

[Claims] 1. A forward hydraulic clutch of friction type.
(C ₂ ) and a reverse hydraulic clutch (C ₁ ), and a valve mechanism for adjusting the pressure of hydraulic oil supplied to the hydraulic clutches (C ₂ ), (C ₁ ).
(V ₂ ), (V ₁ ) and the measuring means (S) for detecting the acceleration (X) on the lower side of the forward and reverse hydraulic clutches (C ₂ ) and (C ₁ ) in the traveling system. provided with, one of the hydraulic clutch _{(C 2), (C 1} ) to operate in the cut state from the state to enter, and the other of the hydraulic clutch (C _2), the operation state enters by supplying hydraulic fluid to (C ₁₎ During forward / reverse switching operation, the acceleration (X) detected by the measuring means (S) is changed from the direction of the hydraulic clutches (C ₂ ), (C ₁ ) on the one side to the hydraulic pressure on the other side. When the clutch (C ₂ ), (C ₁ ) is switched to the direction and the predetermined value (β) of the direction of the hydraulic clutches (C ₂ ), (C ₁ ) on the other side is reached, the predetermined value (β) is reached. When the hydraulic oil reaches the pressure set in the other side hydraulic clutches (C ₂ ) and (C ₁ ) for a set time (T ₃ ).
For a period of time, and when the set time (T ₃ ) has elapsed, the hydraulic oil pressure is increased from the pressure when the predetermined value (β) is reached and the hydraulic clutch (C ₂ ) A hydraulic clutch device for traveling of a work vehicle, which is provided with control means (T) for operating the valve mechanisms (V ₂ ) and (V ₁ ) so that (C ₁ ) is turned on.