JPH0792144B2 - Work vehicle traveling speed change structure - Google Patents

Description

TECHNICAL FIELD The present invention relates to a speed change structure of a traveling system in a work vehicle such as a passenger type rice transplanter or an agricultural tractor.

[Conventional technology]

In a passenger type rice transplanter which is an example of a work vehicle, it has been proposed to equip a hydrostatic continuously variable transmission or a belt type continuously variable transmission as a transmission for traveling, and to perform a gear shift operation with an actuator. .

In this case, attach a potentiometer that detects the operating position of the actuator, and operate the actuator so that the output voltage of the potentiometer falls within the dead zone that includes the set voltage that corresponds to the operating position of the speed change lever (corresponding to an artificial operating tool). It

[Problems to be Solved by the Invention]

In the above-described configuration, the shift operation is performed on the assumption that the voltage corresponding to the operating position of the actuator is accurately output from the potentiometer.

However, if it is used for a long period of time, the mounting position of the potentiometer to the actuator may become loose or loose, so the operating position of the actuator and the output voltage of the potentiometer may not correspond exactly,
A state occurs in which the output voltage of the potentiometer changes after the operation of the actuator without completely following the operation of the actuator.

In such a state, there occurs a state in which the output voltage of the potentiometer deviates from the dead zone even though the actuator is in the operating position corresponding to the operating position of the shift lever. This causes a so-called hunting phenomenon in which the actuator is moved unnecessarily so that the output voltage of the potentiometer falls within the dead zone, and the riding comfort is reduced.

The present invention aims to suppress such a hunting phenomenon.

[Means for Solving the Problems]

A feature of the present invention is that the traveling speed change structure for a work vehicle as described above is configured as follows. In other words, integrating means for integrating the number of actuator operations,
There is a means for automatically slowing down the control sensitivity of the control mechanism when the cumulative number of actuations of the actuator exceeds a preset number, and there is also a cumulative means for summing the operating time of the work vehicle body and the cumulative total. It is provided with means for automatically blunting the control sensitivity of the control mechanism when the operating time exceeds the set time, and the operation and effect are as follows.

[Work]

As described above, when the actuator is used for a long period of time and the integrated value of the number of times of operation of the actuator and the integrated value of the operation time are equal to or more than the set values, the attachment portion of the potentiometer to the actuator becomes loose or loose. Therefore, if the control sensitivity is reduced in such a case, even if the output voltage of the potentiometer does not exactly correspond to the operating position of the actuator,
Even if the actuator is followed with a delay, the output voltage of the potentiometer is less likely to fall out of the dead zone.

[Advantages of the Invention] As described above, when the frequency with which the output voltage of the potentiometer deviates from the dead zone decreases, the actuator is less likely to be moved unnecessarily, and the hunting phenomenon of the actuator can be suppressed. As a result, a smooth gear shift operation can be performed by the actuator, and a reduction in riding comfort of the work vehicle can be suppressed.

〔Example〕

Hereinafter, an embodiment in which the present invention is applied to a riding type rice transplanter which is an example of a work vehicle will be described in detail with reference to the drawings.

As shown in FIG. 4, an engine (3) is provided at the front of the body supported by front wheels (1) and rear wheels (2), a control section (4) is provided at the center, and a seedling planting device (5) is provided at the rear. A passenger type rice transplanter is constructed. The power from the engine (3) is belt-type continuously variable transmission (6) and gear transmission (7).
It is transmitted to the front wheel (1) and the rear wheel (2) via the PTO shaft (8) and to the seedling planting device (5) via the PTO shaft (8).

The gear transmission (7) is capable of shifting to two forward gears and one reverse gear, and the first gear shift lever (20) performs a gear shift operation. The belt type continuously variable transmission (6) is of a split pulley type as shown in FIG. 2, and is a tension pulley (1) which is oscillated by an electric cylinder as an actuator (18).
9) The gear is changed by.

Then, as shown in FIG. 2, a control panel (22) having a control handle (21) is provided with a second control panel (23) as an artificial operation tool (23).
A gear shift lever is provided, and a signal from a potentiometer (not shown) for detecting the operation position is input to the control device (17). On the other hand, a potentiometer (9) for detecting the expansion / contraction position of the electric cylinder (18) is attached to the electric cylinder (18), and the signal of the potentiometer (9) is input to the control device (17).

Then, as shown in FIG. 1, the output voltage of the potentiometer (9) of the electric cylinder (18) is within the dead zone (X ₁ ) including the set voltage (V ₁ ) from the potentiometer of the second speed change lever (23). The electric cylinder (18) is expanded and contracted so that As a result, the second speed change lever (23)
The shifting operation of the belt type continuously variable transmission (6) is performed so as to correspond to the operation position of.

Next, the driving-related control will be described in detail. As shown in FIGS. 3 and 2, in the belt type continuously variable transmission (6), a main clutch (29) is provided on the gear transmission (7) side, and a clutch for disengaging the main clutch (29). A pedal (30) is provided. And, in the belt type continuously variable transmission (6), a rotation speed sensor (31) for detecting the rotation speed of the engine (3) is attached to the engine (3) side, and the signal thereof is used as a control signal (17). It has been entered.

Then, when starting work or temporarily stopping during planting work, depress the clutch pedal (30) to release the main clutch (29).
When is turned off, this is detected by the clutch switch (32). As a result, the belt type continuously variable transmission (6) is automatically operated to the lowest speed position. Then, when the clutch pedal (30) is returned to the engaged position, that time (the time when the main clutch (29) is completely in the engaged state)
The belt type continuously variable transmission (6) is gradually increased in speed to the speed corresponding to the operation position of the second speed change lever (23). As a result, the aircraft starts to move smoothly (steps (S ₁ ) and (S ₂ )).

As described above, the gear transmission (7) is of a forward two-stage reverse one-stage gear shift type, where the first forward speed is for planted travel and the second forward speed is for road travel. And this gear transmission (7)
When the first speed change lever (20) for the vehicle is operated to the _first forward speed position (F1), a signal from a first forward speed position switch (not shown) for detecting this operation is input to the control signal (17). . When the operation switch for seedling planting apparatus (5) (27) is the planting position, the process proceeds to step (S ₃₎ (Step (S _4), (S _5)).

As shown in FIG. 2, the control panel (22) is provided with an accelerator lever (33) for operating the accelerator of the engine (3), and it is detected that the accelerator lever (33) is at the fully open position. The accelerator switch (34) is provided. When the accelerator lever (33) is in the fully open position during the above-mentioned planting traveling, the belt type is used so that the engine speed detected by the speed sensor (31) is maintained within the set range. The continuously variable transmission (6) is automatically shifted by the electric cylinder (18). In this case as well, similarly to the above, the expansion / contraction operation of the electric cylinder (18) is performed so that the output voltage of the potentiometer (9) falls within the set dead zone (not shown).

However, even if the traveling load is reduced, it is not being operated in the high speed side beyond the speed set by the second shift lever (23) (Step (S _3), (S _6)).

When the accelerator lever (33) is not in the fully open position during the above-mentioned planting traveling, the belt type continuously variable transmission (6) is operated and maintained at a speed corresponding to the operation position of the second speed change lever (23). is (step _{(S 3), (S 7} )).

Furthermore, when the operation switch (27) is operated to a position other than the planting position during traveling with planting, it is determined that one planting process has ended and the aircraft has reached the edge, and the belt type variable transmission (6) is automatically operated at the lowest speed position (step _{(S 4), (S 5} ), (S 8)). As a result, it is possible to turn at a safe low speed on the ridge. Then, when the operation switch (27) is moved to the planting position so as to complete the turning and enter the next planting stroke, the step (S ₅ ) and the step (S ₃ ) to the step (S ₆ ) or the step (S ₇ ) are performed. ), The belt type continuously variable transmission (6) is operated to the speed increasing side and returns to the predetermined planting traveling speed.

In this case, since the operating speed of the electric cylinder (18) for operating the belt type continuously variable transmission (6) is relatively low in step (S ₆ ), the operation switch (27) is operated at the end of turning.
If you move to the planting position and move to step (S ₆ ),
The aircraft slowly accelerates to the prescribed planting speed.

As described above, when the shifting operation of the belt type continuously variable transmission (6) is performed by the electric cylinder (18), the operation issued from the control device (17) to the electric cylinder (18) as shown in FIG. Accumulation means for accumulating the number of signal transmissions (1
0) is equipped with a counter. Then, when the cumulative number of operations recorded in the counter (10) exceeds the set number of times, the dead zone (X ₁ ) is widened to (X ₂ ) as shown in FIG. 1 and at the same time in step (S ₆ ). The dead zone during automatic driving can also be widened. As a result, the control sensitivity when controlling the operation of the electric cylinder (18) is slowed down.

[Another embodiment]

Although the number of times the electric cylinder (18) is operated is integrated in the above-described embodiment, the time during which the work vehicle body is operating, that is, the time during which the engine (3) is operating is integrated, and the integrated operating time is calculated. The dead zone may be widened when the set time is exceeded.

In addition, the control sensitivity may be weakened by changing the amplification factor of the output of the potentiometer (9) of the electric cylinder (18) as a means for weakening the control sensitivity, instead of widening the dead zone.

It should be noted that although symbols are added to the claims for convenience of comparison with the drawings, the present invention is not limited to the structure of the accompanying drawings by the entry.

[Brief description of drawings]

The drawings show an embodiment of a traveling speed change structure for a work vehicle according to the present invention. FIG. 1 is a view showing a dead zone in traveling control, and FIG. 2 is a state in which various parts of a control panel and a belt type continuously variable transmission are linked. Fig. 3 and Fig. 3 are flowcharts showing the flow of traveling control, and Fig. 4 is an overall side view of the riding type rice transplanter. (6) …… Transmission gearbox, (9) …… Potentiometer, (10) …… Integration means, (18) …… Actuator, (23) …… Humanized manipulator, (X ₁ ) …… Dead zone.

Claims (2)

[Claims] 1. An actuator (18) for shifting a traveling transmission (6), a potentiometer (9) for detecting an operating position of the actuator (18), and an artificial operating tool (23). A traveling speed change structure for a work vehicle, comprising: a control mechanism that operates an actuator (18) so that the output voltage of the potentiometer (9) is within a dead zone (X ₁ ) including a set voltage corresponding to speed. An integrating means (10) for accumulating the number of operations of the actuator (18), and means for automatically blunting the control sensitivity of the control mechanism when the cumulative number of operations of the actuator (18) exceeds a set number. The structure for changing the traveling speed of a working vehicle. 2. An actuator (18) for shifting the traveling transmission (6), a potentiometer (9) for detecting the operating position of the actuator (18), and an artificial operating tool (23). A traveling speed change structure for a work vehicle, comprising: a control mechanism that operates an actuator (18) so that the output voltage of the potentiometer (9) is within a dead zone (X ₁ ) including a set voltage corresponding to speed. A traveling speed change structure for a work vehicle, comprising: an integrating means for integrating the operating time of the work vehicle main body; and a means for automatically slowing down the control sensitivity of the control mechanism when the integrated operating time exceeds a set time.