JP3488055B2 - Work vehicle - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a transmission system for transmitting power from the engine to the travel device, comprising: a plurality of kinds of transmission gears to be shifted operation, and a hydraulic clutch, when the shift operation
In addition to configuring a transmission with a hydraulic control mechanism that operates the hydraulic clutch from the disengaged state from the disengaged state , a drive elevating mechanism that connects the ground work device to the traveling vehicle body in a freely elevating manner,
Regarding a work vehicle provided with a control device that controls a drive lifting mechanism based on a work signal when working with a ground work device,
More specifically, the present invention relates to a technique for setting a boosting characteristic when a hydraulic clutch is engaged.

[0002]

2. Description of the Related Art As a work vehicle constructed as described above, there is a work vehicle disclosed in Japanese Patent Publication No. 3-72846. In this conventional example, a load acting on a traveling system is set to a setting position of an engine governor and an engine. And a control operation is set such that the larger the load thus determined is, the higher the initial boosting speed when the hydraulic clutch is engaged is.

[0003]

Taking an agricultural tractor as an example of a work vehicle, in the case of working with a plow in an agricultural tractor, all of the traction load acts on the traveling system, and the value of this load and the load acting on the engine. Is proportional to the value of.
However, in normal work using a rotary tiller, the rotary force of the tilling claw of the rotary tiller acts in the direction to move the car body forward, so even when the load acting on the engine is large, the tiller of the tiller is used during work. The load acting on the traveling system is reduced by the force of the time, and in the work using such a rotary tiller, the boosting characteristic of the hydraulic clutch is determined based on the engine load as in the conventional example. If set, there is room for improvement as a result of a quick on / off operation, which causes a shock during the on / off operation of the hydraulic clutch.

An object of the present invention is to rationally construct a work vehicle which engages and disengages a hydraulic clutch with an appropriate boosting characteristic in accordance with a work mode without using a complicated structure.

[0005]

The first feature (Claim 1) of the present invention According to an aspect of the plural kinds of speed change gear transmission system, which is gear shifting in a shift operation for transmitting the power from the engine to the travel device
And a hydraulic clutch, which constitutes a transmission with a hydraulic control mechanism for operating the hydraulic clutch from a disengaged state during a shift operation, and a drive lift for connecting a ground work device to a traveling vehicle body in a freely movable manner. in mechanism and the work vehicle and a control device for controlling the driving elevating mechanism based on the work signal during work using the ground work apparatus, engine
Based on the detected load due to changes in the engine speed, the hydraulic clutch
Boosting means for switching the boosting characteristic of the operating part
A ground work device that is equipped with and is connected to the traveling vehicle body
Is the working mode of the rotary working device.
In a work mode that is performed without a rotary work device
Comprising means for determining whether the, the shift of the transmission
Supplied to the hydraulic clutch at the time of engaging operation of the hydraulic clutch
The boosting characteristics of the hydraulic oil to be boosted by the boosting means are
Rotary work is carried out based on the result of discrimination by other means.
The boosting characteristics set corresponding to the
It is set according to the work mode that is performed without using the work device.
It is configured so that the setting can be changed to either
Located point are its action, and the effects are as follows.

A second feature of the present invention (claim 2) is that in claim 1, the work is performed by a ground work device connected to the traveling vehicle body.
If the work style is a work style with a rotary work device,
Gradient of the pressure rising characteristic of the hydraulic oil supplied to the hydraulic clutch
Work type that is set to and performed without using a rotary work device
Pressure of hydraulic oil supplied to the hydraulic clutch
The characteristic is that it is set to a steep slope , and its action and effect are as follows.

The third feature (claim 3) of the present invention corresponds to the case where rotary work is being performed in claim 1 .
The boosting characteristics of the rotary working device are based on the results of the working depth detection.
It has been set .

[Operation] According to the first feature described above, since the boosting means switches the boosting characteristic of the hydraulic oil supplied to the hydraulic clutch based on the working mode of the ground work device connected to the traveling vehicle body, it acts on the engine. It is possible to set the boosting characteristic in consideration of the load that actually acts on the traveling system, as compared with the case where the boosting characteristic of the hydraulic clutch is set based on the load. In addition, the ground connected to the vehicle body
Since the work form is determined based on the work device, the traveling system
Without special sensors to measure the load acting on
It is possible to set an appropriate boosting characteristic.

According to the above-mentioned second feature, the higher the load on the traveling system, the steeper the step-up of the hydraulic clutch when the hydraulic clutch is engaged, so that the transmission torque does not become insufficient at the initial stage of gear shifting. The vehicle speed is not significantly reduced when shifting.

[0010]

[Effect of the Invention] According to the configuration of the invention according to claim 1, a working vehicle that performs the operation of engaging the hydraulic clutch with an appropriate boosting characteristic corresponding to the work mode without using a complicated structure is rational. It was constructed. Also, the load that actually acts on the running system
Even if you do not use sensors to measure, the hydraulic
The latching operation can be performed. According to the constitution of claim 2
With this, it is possible to perform the operation of engaging the hydraulic clutch with an appropriate boosting characteristic corresponding to the load on the traveling system .

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, an engine 3 is arranged at a front position of a vehicle body including a steering type driven front wheel 1 and a driving type rear wheel 2.
A transmission system for transmitting the power from the engine 3 to the mission case 5 via the main clutch 4 installed in the main clutch housing is formed, and further, the steering handle 6 and the driver's seat 7 are arranged at the center position of the vehicle body. An agricultural tractor is configured by including a pair of left and right lift arms 9 that are lifted and lowered by a lift cylinder 8 as a drive lift mechanism provided at a position above a rear end of the case 5.

As shown in FIG. 2 and FIG. 2, this tractor is provided with a rotary tilling device or a ground working device A such as a plow at the rear end position of the vehicle body so that the cultivating work can be performed. When using the device, the cultivating device is supported through a three-point link mechanism including a top link 11 and a pair of left and right lower links 12, and the lower link 12 and the left and right lift arms 9 are lifted by a lift rod 13. The lift arm 9 can be lifted up and down by being supported in a suspended state via the three-point link mechanism including the top link 11 and the pair of left and right lower links 12 when the plow is used as described above. The lower cultivator is supported via the lower link 12 and the left and right lift arms 9 via the lift rods 13 in a suspended state. It has become one that allows the lifting of the ground work apparatus by driving the Futoamu 9.

As shown in FIGS. 1, 2 and 5, a position lever 14 and a main transmission lever 15 are arranged at a side position of the driver's seat 7, and a potentiometer type is provided at a base end portion of the position lever 14. A position setter 16 is provided, and a potentiometer type lift arm sensor 17 is provided at the base end of the lift arm 9. Further, the rotary tiller is provided with a potentiometer-type cover sensor 19 for measuring the tilling depth from the swing amount of the rear cover 18, and the rod 20 arranged at the connecting position of the left and right lower links 12 is bent at the rear end position of the vehicle body. The strain gauge type load sensor 21 for measuring the traction load is provided. Then, at the time of tilling work using the rotary tiller, the electromagnetically operated control valve 25 for the lift cylinder 8 is operated so that the set value from the potentiometer-type tiller depth setter 22 and the signal value from the cover sensor 19 are balanced. Then, lifting control is performed to raise and lower the tiller, and during plowing work using a plow, an electromagnetic force is applied to the lift cylinder 8 so that the set value from the potentiometer-type load setter 23 and the signal value from the load sensor 21 are balanced. The control operation of the control device 24 is set so that the operation control valve 25 is operated to perform the elevating control for elevating the tiller.

The control device 24 comprises a microprocessor, and a signal line from the cover sensor 19 to the control device 24 is provided with a separable connector 26, and the connector 26 is pulled from the position to the control device 24 side. A voltage is applied via the up resistor 27. From this, when the connector 26 is connected, the signal voltage from the cover sensor 19 is maintained in a predetermined range, so it is determined that the operation is performed using the rotary tiller, and when the connector 26 is disconnected, the control is performed. Since the signal voltage input to the device 24 rises to approximately the power supply voltage, it is determined that the work is using a plow, and the control device 15 controls the valve for the speed change clutch C described later based on the determination result. Clutch C
It is designed to switch the boosting characteristic when the switch is turned on.
Further, a pressure sensor PS for measuring a pilot pressure of a hydraulic system, which will be described later, with respect to the control device 24, and an accelerator sensor 28 for measuring an operation position of an accelerator lever (not shown) for setting the rotation speed of the engine 3. , An input system from an engine speed sensor 29 for measuring the speed of the engine 3 is formed.

As shown in FIG. 3, a transmission system for transmitting the power from the engine 3 to the external power drive shaft 30 via the transmission system inside the main clutch 4 and the transmission case 5 is formed. A transmission system that transmits the front wheel 1 and the rear wheel 2 via a speed change system in the transmission case is formed.

That is, the power from the transmission shaft 31 to which the power from the engine 3 is transmitted is converted into the clutch mechanism 3 for external power.
A system for transmitting the power from the power transmission shaft 31 to the external power take-off shaft 30 via the forward clutch 3 is formed.
3, or transmitted to the tubular shaft 35 via the reverse clutch 34, and the power from the tubular shaft 35 is transmitted to the main transmission device B, the transmission clutch C (an example of a hydraulic clutch), the first auxiliary transmission device D, the second transmission device. A transmission system is formed to transmit the differential gears 2A of the rear wheels 2 via the sub transmissions E, respectively, and further, the power from the second sub transmission E is transmitted via the front wheel transmission F and the intermediate transmission shaft 36. A transmission system that transmits the differential to the differential 1A of the front wheel 1 is formed.

The forward clutch 33 and the reverse clutch 34
Both are configured as a wet multi-plate type in which a pressure oil is supplied to turn on and a discharge oil is turned to a disengaged state. When the reverse clutch 34 is turned on and operated, a reverse power is supplied to the tubular shaft through an idle gear and a reverse shaft 37. 35, and when the forward clutch 33 is engaged and operated, the power from the transmission shaft 31 is directly transmitted to the tubular shaft 35.

In the main transmission B, four gears are arranged on the axis of the transmission shaft 31, and the gears are constantly engaged with each other.
One gear is provided on the counter shaft 38, and a pair of synchromesh type speed change sleeves S1, S1 are provided on the shaft center of the transmission shaft 31.
Are arranged, and one of these synchromesh type shift sleeves S1 and S1 is selected and a shift operation is performed to shift the traveling speed to four stages. , S1 are linked to hydraulic cylinders T1 and T2 for shift operation.

The speed change clutch C is of a wet multi-plate type in which it is turned on when pressure oil is supplied and is turned off when oil is discharged. The first auxiliary transmission device D includes two gears provided on a tubular shaft 39 to which power from the speed change clutch C is transmitted, and a counter shaft 38 of the main transmission device B in a state in which the gears are constantly meshed with these gears. 2 placed on the axis
And a gear shift type that shifts the traveling speed to two stages by shifting the shift sleeve S2. The shift sleeve S2 is linked to a hydraulic cylinder T3 for shift operation. Further, a transmission clutch G is disposed between the counter shaft 38 of the main transmission B and the shaft system supporting the transmission sleeve S2 of the first auxiliary transmission D, and the transmission clutch G is disengaged by the supply of pressure oil. , A spring (not shown) installed by oil drainage is configured to maintain a slip-in state in which slipping is allowed.

The second sub-transmission device E, like the first sub-transmission device D, is provided with two gears, two gears that constantly mesh with the two gears, and a synchromesh type transmission sleeve. In addition, by operating a synchromesh type shift sleeve with a manually operated shift operating tool (not shown), the traveling speed can be shifted in two steps. Further, the front wheel transmission device F is provided with a hydraulic clutch that is hydraulically operated so that the peripheral speed of the front wheel 1 is equal to the peripheral speed of the rear wheel 2, and the peripheral speed of the front wheel 1 is equal to the rear wheel. It is configured so that it can be switched to a state in which it is transmitted at a higher speed than the peripheral speed of 2.

As shown in FIG. 4, a hydraulic circuit for gear shift operation is constructed, and this hydraulic circuit is provided with a hydraulic pump 41 driven by the engine 3, and the hydraulic pump 4 is also provided.
The pressure oil from No. 1 is transmitted through the oil passage 42 to the main transmission lever 15
A system for supplying pressure to the rotary valve 43 operated by is formed, and an oil passage system for supplying pressure oil from the rotary valve 43 to the three hydraulic cylinders T1, T2, T3 is formed. As shown in the figure, the two hydraulic cylinders T1 and T2 linked to the main transmission B are each a piston 45 that slides with respect to the cylinder tube 44, and a cylinder that is fitted onto the rod portion of the piston 45. A movable piston 46 that is fitted in the tube 44. The rotary valve 43 to the hydraulic cylinders T1, T
By selecting three oil passages for No. 2 and supplying hydraulic oil, three states, that is, a state where the synchronizer links S1 and S1 are shifted to the operation end and a state where they are held at the neutral position, can be realized. . The first auxiliary transmission device D
The hydraulic cylinder T3 with respect to is provided with a piston 45 slidably movable with respect to the cylinder tube 44,
The synchromesh type speed change sleeve S2 is configured to be switchable between two positions.

An electromagnetic proportional control type first switching valve 48 is provided in an oil passage 49 for supplying the hydraulic oil from the hydraulic pump 41 to the speed change clutch C, and the hydraulic oil from the hydraulic pump 41 is transferred to the transmission clutch G. The pilot pressure-operated second switching valve 50 is provided in the oil passage 47 supplied to the. Cylinder tubes 44 of the three hydraulic cylinders T1, T2, T3,
Pilot oil passages 51, 52, 53 are formed in 44, 44, respectively, in which the oil is drained only in the neutral state, and the pressure from the pilot oil passage 53 from the hydraulic cylinder T3 to the first auxiliary transmission D is changed to the second oil pressure. An oil passage leading to the switching valve 50 is formed, and two pilot pressure control type control valves 5 are provided for this oil passage.
An oil passage is formed so as to switch the control valves 54, 54 by the pressure from the pilot oil passage from the hydraulic cylinders T1, T2 for the main transmission B. A pressure sensor PS for measuring pressure is provided. Further, a forward / reverse switching valve 56 is provided in an oil passage 55 for supplying the hydraulic oil from the hydraulic pump 41 to the forward clutch 33 and the reverse clutch 34, and this valve 56 is operated by a manually operated switching lever 57. It has become one.

Since the shift system is formed in this manner, when the traveling speed is changed, the main shift lever 15 is simply operated to a desired shift speed, and the rotary valve 43 is operated in association with the shift operation. The operation of the corresponding hydraulic cylinder is started by the hydraulic oil of the above, and the pressure sensor PS measures the pressure of the pilot oil passage linked with this and the control device 24
When the control valve controls the first switching valve 48 to disengage the transmission clutch C, the second switching valve 50 is controlled by the pressure from the pilot oil passage 53 and the transmission clutch G is turned on and off at substantially the same time so that the transmission clutch G is operated. The transmission is started in a state where slippage is allowed in the transmission in this way, which allows the front and rear wheels to continue to be driven even during gear shifting.This hydraulic cylinder changes the pilot pressure when the shift operation is completed. Measured by the pressure sensor PS, the control device 24 controls the first switching valve 48 to engage and operate the transmission clutch C, and at the same time as this, the second switching valve 50 is turned off based on the pressure change in the pilot oil passage. It is operated and the gear shifting is completed.

Further, the first switching valve 48 is constructed so that the opening degree of the valve is set corresponding to the value of the current supplied to the electromagnetic solenoid, and the control device 24 is operated when the shift clutch C is engaged. The type of the work device A connected to the vehicle body is discriminated from the state of the connector 26 to adjust the opening degree of the first switching valve 48.
In addition, the boosting characteristic of the shift clutch C is set.

That is, as shown in the flowchart of FIG. 6, the control device 24 obtains the set engine speed based on the signal from the accelerator sensor 28, and the engine speed based on the signal from the engine speed sensor 29. Is calculated, the value of the load acting on the engine 3 is measured from the difference in the number of revolutions, and the ground height of the ground work device A is measured based on the signal from the lift arm sensor 17 to obtain the ground work device. When A is at a low level, it is determined to be a working state, and when the ground work device A is at a high level separated from the ground, it is determined to be a non-work state, and the ground work device A is separated from the ground. In this case, the load acting on the traveling system is in direct proportion to the load on the engine 3, and since the load is small, the boosting characteristic corresponding to the light load is set (#
101- # 103 steps).

Next, the control device 24 measures the voltage from the connector 26, and if the voltage is within a predetermined range, it is determined that the signal from the cover sensor 19 is input, and the voltage of the connector 26 is determined. When the voltage from 1 to 3 has almost risen to the power supply voltage, it is determined that the connector 26 is separated and the work is performed using the plow. When it is determined that the work is using a plow, the load acting on the traveling system is in direct proportion to the load on the engine 3,
Moreover, since the load is large, the boosting characteristic corresponding to the heavy load is set, and when it is determined that the work is performed using the rotary tiller, the force acting from the rotary tiller to the side that advances the vehicle body is advanced. Based on a signal from the lift arm sensor 17 (cover sensor 1
(The signal from 9 may be used.) The tilling depth is measured, and the boosting characteristic is set based on this tilling depth (steps # 104 to # 107).

In the plowing work using the plow, the traction load acts strongly on the traveling system, resulting in the shift clutch C
The pressure rising characteristic is set so that the pressure is raised steeply (quickly) during the turning operation, and in the tilling work using the rotary tiller, it is caused by the rotating force of the tilling claw in direct proportion to the depth of the tilling depth. As a result of the large force acting in the direction in which the vehicle body moves forward, the load acting on the traveling system is reduced. Therefore, the deeper the plowing depth, the more gradually the pressure increase at the time of operation of engaging the shift clutch C (slower speed). ) When the boosting characteristic to be performed is set and the ground work device A is in the non-grounded state, the load acting on the traveling system is
Since the work is smaller than the work using the rotary cultivator, the boosting characteristic is set so that the boosting at the time of the operation of engaging the shift clutch C is performed at the gentlest gradient (slow speed).

Next, when it is determined by the pressure sensor PS that the pilot pressure has decreased, it is determined that the gear shifting operation has been started, the first switching valve 48 is set to the fully open state, and the oil discharged from the gear shift clutch C is discharged. When it is determined that the pilot pressure has risen by the pressure sensor PS and it is determined that the shift operation has been completed, the current is supplied to the first switching valve 48 so that the current value tends to increase, and the shift operation is performed. The operation of engaging the clutch C is started (steps # 108 to # 110).

Next, when the shifting operation of the shift clutch C is started in this manner, the current having the boosting characteristic set as described above is supplied to the first switching valve 48, so that the boosting operation corresponding to the working mode is performed. The shift clutch C is turned on and off according to the characteristics, and this pressure increase is continued until it is determined that the pressure increase is completed based on the signal from the pressure sensor PS (steps # 111 to # 112). Further, when increasing the pressure at the time of engaging the shift clutch C in this way, the control device 24 as the pressure increasing means starts the supply of the intermittent signal to the electromagnetic solenoid of the first switching valve 48, and at the same time, the intermittent signal is generated. By changing the length of the ON time of (NO) (PWM type control), the current value supplied to the electromagnetic solenoid is adjusted to obtain a desired opening change.

By setting the control operation in this way, even when the ground work device A is traveling away from the ground, such as when traveling on the road, or when using a plow,
Even when working with a rotary cultivator, a shift clutch associated with shifting can be set by automatically determining the working mode and setting the appropriate boosting characteristics without the need to spend time and effort such as operating switches in accordance with the working mode. It enables smooth gear shifting without generating a shock when the vehicle is turned on. In particular, when working with a rotary tiller, the boosting characteristics are set in consideration of the magnitude of the force on the side that advances the car body from the plowing claws, which results in smooth shifting regardless of the working depth. Is made possible.

[Other Embodiments] In addition to the above-described embodiments, the present invention is mechanically compatible with the structure and form of the ground work device when the ground work device is connected to the vehicle body. By configuring the switch to be operated, it is possible to determine the ground work device connected to the vehicle body.

[Brief description of drawings]

FIG. 1 is an overall side view of a tractor to which a rotary tiller is connected.

FIG. 2 is a side view of a plow connected to a tractor.

FIG. 3 is a schematic diagram of a traveling transmission system of a tractor.

FIG. 4 is a hydraulic circuit diagram for shifting.

FIG. 5 is a block circuit diagram of a control system.

FIG. 6 is a flowchart of control operation

[Explanation of symbols]

3 engine 8 Drive lifting mechanism 24 Control device A Ground work device C hydraulic clutch T actuator

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) F16D 48/02 B60K 41/22

Claims (3)

(57) [Claims] Claim: What is claimed is: 1. A transmission system for transmitting motive power from an engine to a traveling device, wherein a plurality of types of speed change gears are changed by a shift operation.
And a hydraulic clutch, and a transmission that includes a hydraulic control mechanism that turns on and off the hydraulic clutch during a shift operation to configure a transmission, and a drive that connects a ground work device to a traveling vehicle so that the work implement can be moved up and down. A work vehicle including a lifting mechanism and a control device that controls a drive lifting mechanism based on a work signal when working with a ground work device , wherein a hydraulic pressure is calculated based on a load detected by a change in engine speed.
Boosting that switches the boosting characteristics of the operating part supplied to the clutch
Forming work by means of a ground work device provided with means and connected to the traveling vehicle body
Is the working mode of the rotary working device?
Determine whether the work is done without the work device
When a hydraulic clutch is engaged during a gear shift of the transmission,
By the pressure increasing means for the hydraulic oil supplied to the hydraulic clutch,
Based on the discrimination result by the discrimination means,
It was set corresponding to when rotary work is being performed.
Step-up characteristics and work performed without using a rotary working device
Change the setting to either the boosting characteristic set according to the mode.
A work vehicle configured to be upgraded . 2. A ground work device connected to a traveling vehicle body
When the work form is the work form of a rotary work device
Loosely regulates the boosting characteristic of the hydraulic oil supplied to the hydraulic clutch.
Work that is set on the distribution and does not use a rotary work device
Mode, the hydraulic oil supplied to the hydraulic clutch rises.
The work vehicle according to claim 1 , wherein the pressure characteristic is set to a steep slope . 3. Corresponding to the case where rotary work is being performed.
The boosting characteristic to be set is based on the result of the working depth detection of the rotary working device.
The work vehicle according to claim 1, wherein the work vehicle is set according to the above.