JP3340913B2 - Work vehicle speed control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect a shift state of a continuously variable transmission as control information to control practice of restraint control to restrain change- over to an automatic shift control mode in simple constitution and favourably in precision. SOLUTION: A control device is provided with a speed change state detection means to detect a shift state of a continuously variable transmission and a restraint means 31B to practice restraint control to restrain practice of automatic shift control by a car speed control means 31A at the time when the shift detection means detects a shift state for control stop regardless of a practice command of automatic shift control of the continuously variable transmission by a command means 52. A potentiometer 41 to be equipped to be operated in accordance with shift operation of the continuously variable transmission is provided as a shift state detection means in this case, and the restraint means 31B is constituted to practice restraint control in accordance with a detection value of the potentiometer 41.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine load for detecting a load of an engine, in which a speed change device which is artificially operated in a forward / reverse direction is mechanically interlocked with a transmission section of a continuously variable transmission for traveling. Vehicle speed control for executing automatic shift control for automatically shifting the continuously variable transmission so that the load of the engine is maintained at a set target load based on detection information of the detection means and the detection information of the engine load detection means; Means, command means for instructing the vehicle speed control means to execute the automatic shift control, shift state detecting means for detecting a shift state of the continuously variable transmission, and execution of the automatic shift control by the command means Regardless of the command, when the shift state detecting means detects a shift state for control stop, a checker who executes a check control for checking execution of the automatic shift control by the vehicle speed control means. About vehicle speed control apparatus for working vehicle provided with.

[0002]

2. Description of the Related Art In such a vehicle speed control device for a work vehicle, a manual shift operation mode in which a continuously variable transmission is manually shifted by a shift operation tool, and an automatic vehicle speed control so that an engine load is maintained at a target load. In order to perform control, the continuously variable transmission is configured to be operated by switching to an automatic transmission control mode in which an automatic transmission is operated by an actuator, and switching from the manual transmission operation mode to the automatic transmission control mode is performed by:
It is performed by a command from the command means. And, from the manual shift operation mode to the automatic shift control mode,
It is necessary to switch when the continuously variable transmission is in a predetermined shift state. Therefore, a shift state detecting means for detecting the shift state of the continuously variable transmission is provided, and when the shift state detecting means detects the shift state for stopping the control, regardless of the execution command of the automatic shift control by the command means, Checking means for checking the switching to the automatic shift control mode is provided.

Conventionally, as a shift state detecting means, there is provided a lever member provided so as to be displaced in accordance with a shift operation tool being moved to an area where the stepless transmission is shifted to a neutral state. For example, a switch that is turned on when the position of the lever member is displaced is provided. By the way, in the case where the continuously variable transmission is constituted by a hydrostatic continuously variable transmission, a reverse traveling speed change operation is also possible. A lever member and a switch similar to those described above are provided so as to detect that the moving operation has been performed. Then, based on the turning-on of the switch, the shift state for control stop is detected.

[0004]

By continuously moving the speed change operation tool within a predetermined area, the continuously variable transmission is shifted. The speed change operation is performed within a predetermined neutral area of the area. When the tool is moved, the continuously variable transmission is shifted to a neutral state.
Incidentally, in the hydrostatic continuously variable transmission, there is also provided a reverse region in which the continuously variable transmission performs a shift operation in a reverse traveling state.

Therefore, in the conventional device, the lever member and the switch are displaced and the switch is turned on when the speed change operation tool is located in the entire region in the neutral region or the entire region in the reverse region. Thus, the configuration of the lever member and the switch is complicated. In addition, since there are variations in the mounting positions of the shift operation tools, adjustment of the installation positions of the lever member and the switch is complicated.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a continuously variable transmission as control information for controlling execution of a check control for checking a switch to an automatic shift control mode. It is an object of the present invention to enable a shift state to be accurately detected with a simple configuration.

[0007]

According to the first aspect of the present invention, a detection value corresponding to a shift state of the continuously variable transmission is output from the potentiometer with a shift operation of the continuously variable transmission. The control means executes the control based on the detected value of the potentiometer. That is, by providing the potentiometer so as to be operated in accordance with the shift operation of the continuously variable transmission, the potentiometer outputs a detection value corresponding to the shift state of the continuously variable transmission. Thus, the shift state of the continuously variable transmission can be detected. Moreover, after the potentiometer is installed, the actual shift state of the continuously variable transmission can be associated with the detected value of the potentiometer. Therefore, high accuracy is not required for the position of the potentiometer, and the shift state of the continuously variable transmission can be accurately detected. As a result, the shift state of the continuously variable transmission can be accurately detected with a simple configuration.

[0008] By the way, such a work vehicle is configured to perform a predetermined work. However, when a load is applied to the engine while the predetermined work is being performed, the automatic transmission control mode is set. Is required to be switched. For example, such a work vehicle may be provided with a mowing device for cutting planted grain culms and a threshing device for threshing cut grain culms. Features according to claim 1
According to the present invention, the threshing device is provided by the switching
Is detected or not, and the stalk detection means detects
The harvesting device detects the presence of planted grain culms to be harvested.
The switching state detection means detects that the threshing device has stopped.
When issued, and the planted cereal stem by the cereal stem detection means
Even when not detected, the restraint control is executed. Follow
Work equipment equipped with a mowing device and a threshing device
When there is no planted culm to cut and threshing equipment
When is not operating, switch to the automatic transmission control mode.
As replacement is checked, mowing equipment is used to cut planted grain culms.
The state in which it is taking, and the state in which the threshing device is operating,
That is, the load in the actual working state is
Automatic shift control mode only when engaged
Can be switched.

According to the second aspect of the present invention, there is provided a stepless motor.
With the shifting operation of the transmission, from the potentiometer,
A detection value is output according to the shift state of the continuously variable transmission, and
Control means, based on the detected value of the potentiometer,
The restraint control is executed. In other words, without potentiometer
Equipped so that it can be operated in conjunction with the shifting operation of the stepped transmission.
By changing the potentiometer,
A detection value is output according to the shift state.
Can be used to detect the speed change state of the continuously variable transmission.
is there. In addition, after the potentiometer is installed, continuously variable speed
Check the actual gear shifting status of the device and the detected value of the potentiometer.
Can be associated. Therefore, potentiometer
High precision is not required for the installation position of
Can accurately detect the speed change state of the continuously variable transmission.
it can. As a result, the speed of the continuously variable transmission can be changed with a simple configuration.
The state can be detected with high accuracy.

[0010] By the way, if the load on the engine suddenly increases while the automatic shift control is being executed, the automatic shift operation of the continuously variable transmission is performed at a high speed in order to follow the sudden increase, and the work vehicle is moved. Automatic shift control may be performed until the vehicle stops. In such a case, the load on the engine becomes large temporarily, and it often returns to an appropriate state immediately.However, once the work vehicle has stopped, it takes time and effort to return it. Improvement was desired. According to the characteristic configuration of the second aspect, the reduction is achieved.
During the automatic shift control to the high speed side, the potentiometer
When the detected value is lower than the value corresponding to the stopped state,
When the set value is reached, automatic transmission control is interrupted,
The continuously variable transmission is operated to maintain the lower limit set value,
Again, the target load is detected by the engine load detecting means.
Then, the automatic shift control is executed. In other words, the engine
Work vehicle stops even if the load
Until the load on the engine returns to an appropriate state.
The vehicle speed of the work vehicle is maintained at a preset low speed.
Is done. Therefore, during operation in the automatic transmission control mode,
Even if the load on the engine suddenly increases,
The problem that the industrial vehicle stops is solved.
In addition, it is slow that the load on the engine returns to the proper state.
If there is a risk that the engine will be overloaded,
At the author's discretion, switch to manual shift operation mode and
The gin can be prevented from being overloaded.

[0011] According to the characteristic configuration of the third aspect, steplessly
With the shifting operation of the transmission, from the potentiometer,
A detection value is output according to the shift state of the continuously variable transmission, and
Control means, based on the detected value of the potentiometer,
The restraint control is executed. In other words, without potentiometer
Equipped so that it can be operated in conjunction with the shifting operation of the stepped transmission.
By changing the potentiometer,
A detection value is output according to the shift state.
Can be used to detect the speed change state of the continuously variable transmission.
is there. In addition, after the potentiometer is installed, continuously variable speed
Check the actual gear shifting status of the device and the detected value of the potentiometer.
Can be associated. Therefore, potentiometer
High precision is not required for the installation position of
Can accurately detect the speed change state of the continuously variable transmission.
it can. As a result, the speed of the continuously variable transmission can be changed with a simple configuration.
The state can be detected with high accuracy. Ma
According to a third aspect of the present invention, the switching state is provided.
The detection means detects whether the threshing device is operating.
Is cut out and cut by the reaping device by the grain stalk detection means.
The presence / absence of a planted grain culm to be detected is detected, and the switching state detection means
When the halt of the threshing device is detected by
Even when the detection means does not detect the planted culm,
The control is executed. Therefore, the mowing device and threshing device
In the work vehicle provided, there are no planted grain culms to be cut.
And when the threshing device is not operating,
Since switching to the dynamic shift control mode is suppressed,
The state where the planted grain culm is cut by the device, and threshing equipment
In the operating state, that is, in the actual working state.
When the load is applied to the engine
Only, it is possible to switch to the automatic transmission control mode. Sa
Furthermore, according to the characteristic configuration of the third aspect, during execution of the automatic shift control to the deceleration side, when the detection value of the potentiometer reaches the lower limit set value on the high speed side than the value corresponding to the stop state. The automatic transmission control is interrupted, and the continuously variable transmission is operated to maintain the lower limit set value.
When the target load is detected by the engine load detecting means, automatic shift control is executed. That is, even if the load on the engine suddenly increases, the work vehicle does not stop and the vehicle speed of the work vehicle is maintained at a preset low vehicle speed until the load on the engine returns to an appropriate state. . Therefore, the problem that the work vehicle stops even if the load on the engine suddenly increases during operation in the automatic transmission control mode is solved. When the load on the engine returns to an appropriate state slowly, and there is a risk that the engine may be overloaded, the mode may be switched to the manual shift operation mode at the discretion of the operator, and the engine may be overloaded. Can be avoided.

According to the fourth aspect of the present invention, the traveling shift is performed using the belt-type continuously variable transmission. The belt-type continuously variable transmission can be configured at a lower cost than hydraulic transmissions and the like, and is advantageous in configuring an inexpensive vehicle speed control device with good operability.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 4 shows a transmission system of a self-removing type combine which is an example of a work vehicle. Power from the engine 1 is transmitted to a threshing device 46 via a belt tension type threshing clutch 45 (corresponding to a transmission mechanism). In addition, the power is transmitted to an input pulley 4 of a belt-type continuously variable transmission 3 via a belt transmission mechanism 2 having a tension clutch, and the power from the continuously variable transmission 3 is transmitted to and from a hydraulic clutch-type transmission case 5 in a transmission case. It is transmitted to the left and right crawler traveling devices 6 via a forward switching device (not shown) and a gear transmission for traveling (not shown). The power separated immediately before the gear transmission is transmitted from the transmission case 5 to the reaping unit 8 (corresponding to a reaping device) at the front of the machine body via the belt transmission mechanism 7. The raising unit (not shown) of the mowing unit 8 is provided with a stock sensor 47 (corresponding to cereal culm detecting means) for detecting the presence or absence of the mowing culm, that is, the cutting traveling state. .

As shown in FIG. 6, an operation lever 48 for turning on and off the threshing clutch 45 is provided with a threshing clutch switch 49 (corresponding to switching state detecting means) which is turned on when the clutch is connected. The engine 1 is provided with an electromagnetic pickup type rotation speed sensor 50 for detecting the rotation speed. Since the rotation speed of the engine 1 decreases as the load increases, the rotation speed sensor 50
It functions as engine load detecting means for detecting the load of the engine 1. Further, a vehicle speed sensor 53 for detecting the actual vehicle speed of the combine by detecting the rotation speed of the crawler traveling device 6 is provided.

Next, the belt-type continuously variable transmission 3 and its shift operation structure will be described. As shown in FIG. 2, a first pulley 11 is provided on an input shaft 9 to which an input pulley 4 is fixed, and a second pulley 12 is provided on an output shaft 10.
Transmission belt 1 over first and second split pulleys 11 and 12
3 is wound. First and second split pulleys 11, 12
Is composed of a pulley portion 14 fixed to the input shaft 9 and the output shaft 10 in a spline structure, and a pulley portion 15 movable in the axial direction.
The pulley portion 15 on the moving side is biased by the spring 16 toward the pulley portion 14 on the fixed side, and the pulley portion 15 on the moving side is moved in proportion to the increase in the load on the output shaft 10 side. Is provided with a cam mechanism 17 for pushing.

A ring member 18 is externally fitted to the pulley portion 15 on the moving side of the first split pulley 11 via a bearing, and a pair of pins 18a fixed to the ring member 18 are recessed on the case side of the continuously variable transmission 3. 19, the ring member 18 is prevented from rotating. As shown in FIGS. 3 and 2, a cylindrical cam member 20 is externally fitted to the input shaft 9 via a bearing, and has a recess formed by a linear bottom portion 20a and a pair of right and left symmetric inclined surfaces 20b. Is the cam member 20
The roller 18b of the pin 18a of the ring member 18 has entered the pair of concave portions of the cam member 20.

In the state shown in FIGS. 2 and 3, the moving pulley portion 15 of the first split pulley 11 is farthest to the left from the fixed pulley portion 14 in the drawing, and the second pulley 12
The pulley portion 15 on the moving side is the pulley portion 1 on the fixed side.
This is the state of the lowest speed position closest to No. 4. When the cam member 20 is rotated right and left from this state, the inclined surface 20
b, the pulley portion 15 on the moving side of the ring member 18 and the first split pulley 11 is connected to the pulley portion 14 on the fixed side.
The pulling operation approaches the side, and the winding radius of the transmission belt 13 around the first split pulley 11 increases. Along with this, the pulley portion 15 on the moving side of the second pulley 12
However, the continuously variable transmission 3 is shifted to the high speed side from the fixed pulley portion 14 to the right in the drawing. Therefore, the cam member 20 functions as a transmission section of the continuously variable transmission 3.

Next, the operation structure of the belt type continuously variable transmission 3 and the forward / reverse switching device will be described. 2 and 1
As shown in FIG. 2, a boss member 21 is fixed to an end of the cam member 20 outside the continuously variable transmission 3, and a sector gear 22 is fixed to the boss member 21. An electric motor 23 is fixed to a fixed portion of the body, and a reduction mechanism 24 using a flat gear is provided on the electric motor 23. A pinion gear 24 a of the reduction mechanism 24 is engaged with the sector gear 22. Boss member 2
1, a ring member 25 is externally fitted,
A gearshift lever 26 (corresponding to a gearshift operating tool) is supported by the gearshift lever.

The shift lever 26 is swingable in the cross direction, and as shown in FIG. 5, forms a guide groove 44a for forward shift of the lever guide, a guide groove 44c for reverse shift, and a step portion for operating state switching. Intermediate guide groove 44b
Rocking operation along each of the guide grooves 4
4a or the reverse shift guide groove 44c, when operated along the deceleration side operation direction, the forward shift guide groove 4c
4a. At the inner edge k of the reverse transmission guide groove 44c, the shift lever 26 is forcibly received and restricted at a position corresponding to the traveling neutral state, so that the traveling state is not switched to the forward / backward traveling state due to excessive operation. Have been.

The pin 25 of the arm 25a of the ring member 25
b has entered the opening 22a of the sector gear 22, and a pair of rubber-like pressure-sensitive sensors 27, 28
Is fixed to the sector gear 22 so as to sandwich the pin 25b. A switching valve (not shown) for switching the forward / reverse switching device between a forward position, a reverse position, and a neutral stop position is provided, and the sector gear 22 and the switching valve are connected to the push-pull wire 2.
9 and the accommodation mechanism 30. That is,
When the shift lever 26 is operated in the normal rotation direction, which is counterclockwise in FIG. 1, the pin 25b comes into contact with the pressure sensor 27 on the normal rotation side, and the detection signal from the pressure sensor 27 on the normal rotation side is detected. Is output, and it is detected that the shift lever 26 has been operated to the forward rotation side. When the shift lever 26 is operated in the reverse direction, which is clockwise in FIG. 1, the pin 25b contacts the pressure sensor 28 on the reverse direction, and a detection signal is output from the pressure sensor 28 on the reverse direction. And the shift lever 26
Is operated to the reverse rotation side.

A potentiometer 41 is mounted on the fixed wall 43 on the side of the continuously variable transmission 3, and a lateral pin 42 a at the tip end of an oscillating lever 42 extending from the potentiometer 41 is formed in a long hole formed in the sector gear 22. 22
b, the potentiometer 41 is provided so as to be operated in accordance with the shift operation of the continuously variable transmission 3 so that the shift state of the continuously variable transmission 3 can be detected. The detection value of the potentiometer 41 is A / D converted in 256 steps, and is read into the control device 31 described later.

As shown in FIG. 6, the drive circuit for driving the electric motor 23 is excited by a signal from the control device 31, and the shift lever 26 swings counterclockwise in FIG. The rotation direction of the electric motor 23 is switched such that the rotation direction of the electric motor 23 is switched and the speed change lever 26 swings clockwise in FIG. A second electromagnetic relay 33 is provided. Electric motor 2 as described above
The first and second electromagnetic relays 32 and 33 for determining the direction of the current supplied to the motor 3 are driven by excitation by transistors 35 and 36, and the power supplied to the electric motor 23 is controlled by a pulse from the controller 31 as described later. Signals P1, P2 ', P
It is controlled by a transistor 37 which operates in response to 2 ″ or the like. In addition, a reference resistor 38 for detecting a value of a holding current A2 supplied to the electric motor 23 to be described later, and a smoothing circuit 39 for smoothing a voltage across the reference resistor 38.
Is provided.

By the way, in this combine, as shown in FIG. 6, an upper limit vehicle speed setting device 51 for setting the upper limit vehicle speed is provided, and a vehicle speed auto switch 52 (corresponding to a command means for instructing execution of automatic shift control) is provided. The transmission 3
Can be switched between a manual shift operation mode and an automatic shift control mode. The upper limit vehicle speed setting device 51 is configured to set the upper limit vehicle speed in three stages, for example, high, medium, and low. In both modes, the manual shift operation mode has priority, and when the shift lever 26 is shifted while in the automatic shift control mode, the operation of the shift lever 26 is detected by the pressure-sensitive sensors 27 and 28. , The mode is switched to a manual shift operation mode.

In the automatic transmission control mode, the control unit 31 controls the transmission 3 based on the information of the rotation speed sensor 50 so that the load of the engine 1 is maintained at the target load.
Is automatically shifted.

More specifically, the stock sensor 47 and the threshing clutch switch 49 are both turned on, and the vehicle speed becomes 0.1 m / m.
The engine speed X when the control condition is satisfied
Is set as the reference rotation speed ST in the no-load state of the engine, and is stored in advance. The speed change electric motor is controlled such that the engine load ST-X defined by the amount of reduction of the engine speed X from the reference speed ST is maintained at a preset target load (target down amount). 23 is the pulse period T of the driving pulse signal (P1).
While changing the ratio T '/ T (hereinafter referred to as duty ratio) of the ON (output) time T' to the speed increase or deceleration side intermittently.

It should be noted that the duty ratio is set to the engine load S so that the transmission 3 can be shifted at a higher speed as the difference between the engine load ST-X and the target load is larger.
The larger the difference between TX and the target load, the larger the value is set. For example, on the speed increasing side, the ON time T ′ is set to 30 to 120 msec for a pulse cycle T of 500 msec.
To set the duty ratio.
On the deceleration side, the duty ratio is set by changing the ON time T 'within a range of 30 to 110 msec for a pulse period T of 500 msec.

Next, the operation of the control device 31 in the automatic transmission control mode will be described with reference to the flowchart shown in FIG. When the pressure sensors 27 and 28 are OFF (step S101), the state of the vehicle speed auto switch 52 is checked (step S102).
If the answer is N, the start condition of the control operation is checked (step S103). In other words, the threshing clutch switch 49 and the stock sensor 47 are turned on, the potentiometer 41 detects the shift state for control execution, and the control condition is established where the vehicle speed is 0.1 m / sec or more and the engine speed X is 500 rpm or more. It is checked whether or not this is the case, and if it is established, the automatic shift control is executed. Note that the shift state for executing the control is such that the potentiometer 41 is in the forward area F (details will be described later).
Is configured to perform detection based on indicating a detected value corresponding to a predetermined set range in. Therefore, when the potentiometer 41 indicates a detected value corresponding to a value outside the set range, the shift state for stopping the control is detected.

In the automatic shift control, the engine speed X is detected, and the engine load ST-X, which is the difference from the reference speed ST set and stored in another processing routine, is set to the target load. Check (Step S10)
4. Step S105).

When the engine load ST-X is larger than the target load, the vehicle speed detected by the vehicle speed sensor 53 is equal to or higher than the preset minimum vehicle speed during automatic shifting, and the detection value of the potentiometer 41 is in the forward range F. When the lower limit set value is higher than or equal to the set lower limit value, the duty ratio setting process is performed to perform a deceleration operation, and when the vehicle speed detected by the vehicle speed sensor 53 is smaller than the automatic shift minimum vehicle speed, or When the detection value of the potentiometer 41 is lower than the lower limit set value, the control device 31 outputs a forward (forward) pulse signal P2 '' described later (steps S106 to S110). Therefore, when the vehicle speed detected by the vehicle speed sensor 53 is smaller than the minimum vehicle speed during automatic shifting, or when the detection value of the potentiometer 41 is lower than the lower limit set value, the transmission lever 26 and the continuously variable transmission 3 is held at the operation position (shift position) at that time.

The minimum vehicle speed during automatic shifting is, for example,
The lower limit value is set to, for example, a value obtained by adding 20 points to the value of the forward region F side end in the neutral region N described later.

If the engine load ST-X is smaller than the target load and the vehicle speed is not at the upper limit of the vehicle speed, the duty ratio is set and the speed is increased (steps S111 and S1).
12, S113).

If it is within the dead zone with respect to the target load, the shift operation is stopped by setting the load to an appropriate state (step S11).
4). If the pressure-sensitive sensors 27 and 28 are ON or the vehicle speed auto switch 52 is OFF, the manual shift mode is set (step S200). Further, even if the vehicle speed auto switch 52 is in the ON state, if the above control condition is not satisfied, the manual shift mode is set.

Therefore, the control device 31 constitutes a vehicle speed control means 31A and a check means 31B.
1B is configured to execute the restraint control based on the detection value of the potentiometer 41.

Next, a manual shift operation mode (step S2)
00), the operation of the belt-type continuously variable transmission 3 and the forward / reverse switching device by the transmission lever 26 will be described with reference to FIGS. 7, 8, 9, and 10. Transmission lever 26
Is operated from one end of the neutral stop region N to the forward side range, the forward / reverse switching device is operated to the forward position by the push-pull wire 29 and the switching valve, and the shift lever 2
When the switch 6 is operated from the neutral stop position N to a range on the reverse side, the forward / reverse switching device is operated to the reverse position by the push-pull wire 29 and the switching valve.

[1] When a lever position storage process is instructed by a command switch (not shown), the shift lever 26 is swung from the neutral position n to the forward upper limit position / reverse upper limit position, and the position of the shift lever 26 is changed. And the value indicated by the potentiometer 41 (0 to 255 points) are stored in the control device 31 (steps S2 and S3). Specifically, as shown in FIG. 5, the swing range of the shift lever 26 is divided into the neutral region N and a forward region F and a reverse region R sandwiching the neutral region N. , Too much area Na on both sides of the center neutral position n
(A set area in the neutral area N) and a pair of starting areas N located on both sides of the excessively steep area Na with an interval.
b (the setting area where the shift lever 26 is located immediately before the start), and the value indicated by the potentiometer 41 is assigned to each area.

[2] When the shift lever 26 starts to be operated to the normal rotation side (or the reverse rotation side) which is counterclockwise in FIG. 1, the pin 25b is moved to the normal rotation side pressure sensor 27 (or the reverse rotation side sensor). Pressure sensor 28) (steps S4, S
5), a signal is input to the control device 31 from the forward-side pressure sensor 27 (or the reverse-side pressure sensor 28). Forward-side pressure sensor 27 (or reverse-side pressure sensor 2)
8) is the first set time T1 (for example, 200 ms) after the reverse operation of the transmission lever 26 (or after the forward operation).
ec (milliseconds)) (steps S6 and S21),
If the shift lever 26 is not at the forward upper limit position (or the reverse upper limit position) (steps S7 and S22), the control device 31 sends a forward rotation (or reverse rotation) pulse signal P as shown in FIG.
1 is output, and the operation current A1 on the normal rotation side (or reverse rotation side) corresponding to the pulse signal P1 is output to the electric motor 23 to perform high-speed normal rotation (or high-speed reverse rotation) (steps S8 and S23).
An assist force along the normal rotation side (or reverse rotation side) is applied to the transmission lever 26 from the electric motor 23.

That is, in the forward area F, the transmission lever 26
Is operated to the forward rotation side, an assist force is applied to the forward rotation side from the electric motor 23, and the continuously variable transmission 3 is shifted to the speed increasing side. When the shift lever 26 is operated to the reverse rotation side, An assist force is applied from the electric motor 23 to the reverse rotation side, and the continuously variable transmission 3 is shifted to the reduction side. Conversely, when the shift lever 26 is operated in the reverse direction in the reverse region R, the assisting force is applied from the electric motor 23 to the reverse direction, and the continuously variable transmission 3 is shifted to the speed increasing side. When the motor 26 is operated to the forward rotation side, an assist force is applied from the electric motor 23 to the forward rotation side, and the continuously variable transmission 3 is shifted to the deceleration side. In this case, as shown in FIG. 11, the duty ratio of the drive pulse signal (P1) is set to 1.0, so that the electric motor 2
3 is in a state of being driven continuously.

[3] In the above [2], the time point detected by the pressure sensor 27 on the forward rotation side (or the pressure sensor 28 on the reverse rotation side) is determined after the reverse rotation operation of the transmission lever 26 (after the forward rotation operation).
Is within the first set time T1 (200 msec) (steps S6 and S21). In this case, when the potentiometer 41 detects a neutral state or a state close to neutral (that is, the shift lever 26 is positioned in the excessively high range Na in the neutral range N) (steps S9 and S2).
4) The electric motor 23 is driven at the very low speed for the second set time T2 so that the forward rotation side pressure sensor 27 (or the reverse rotation side pressure sensor 28) does not detect the operation of the speed change lever 26 to the speed increasing side. Roll (or reverse at a very low speed (step S10,
S11, S25, S26). As a result, the transmission lever 26
Hunting operation is suppressed.

[4] The potentiometer 41 does not detect a neutral state or a state close to neutral (steps S9 and S2).
4) After the reverse rotation operation (or after the forward rotation operation) of the shift lever 26, the first set time T1 has elapsed (step S1).
2, S27), if the shift lever 26 is not at the forward upper limit position (reverse upper limit position) (steps S7, S22), the pulse signal P1 is output from the control device 31, and the operating current A
1 is output to the electric motor 23, and the above-described assist force is applied from the electric motor 23 to the shift lever 26.

[5] The potentiometer 41 does not detect a neutral state or a state close to neutral, and returns to the start point if the first set time T1 has not elapsed after the deceleration operation (steps S12 and S27).

[6] Next, when the operation of the speed change lever 26 is stopped, the signals of the pressure-sensitive sensors 27 and 28 on the normal rotation side and the reverse rotation side are stopped (steps S4 and S5). In this case, when the operation of the shift lever 26 is stopped in the high-speed range F1 of the forward movement region F (step S14), the control device 31 returns to FIG.
A pulse signal P2 ′ on the forward side (forward rotation side) as shown in FIG. In this pulse signal P2 ', the ratio (T' / T) of the output time T 'in one cycle T to the stop time T "
T ″) is set to a sufficiently small value, so that the holding current A2 ′ (the aforementioned operation current A1
Is output to the electric motor 23 (step S15). In the above [4], the holding current A2 'is similarly output to the electric motor 23 when the shift lever 26 is at the forward upper limit position.

When the operation of the shift lever 26 is stopped in the low speed range F2 of the forward movement region F (step S14), the control device 31 causes the forward movement side (forward rotation side) as shown in FIG.
Is output. This pulse signal P
At 2 ″, the ratio T ′ / T ″ is set to a value smaller than T ′ / T ″ at P2 ′, so that the holding current A2 ′ of the predetermined value B ″ on the forward rotation side is set. '(Smaller than the above-mentioned holding current A2') is output to the electric motor 23 (step S16).

In the reverse region R (step S13),
When the operation of the shift lever 26 is stopped, a pulse signal P2 ″ on the reverse rotation side as shown in FIG. 11 is output from the control device 31, and the holding current A2 ″ is output to the electric motor 23 (step S17). . In the above [4], the holding current A2 ″ is similarly output to the electric motor 23 when the transmission lever 26 is at the reverse upper limit position.

The belt-type continuously variable transmission 3 shown in FIG.
Since it is going to return to the neutral stop region N side due to the tension of the transmission belt 13, the small assist force on the forward rotation side (or the reverse rotation side) of the electric motor 23 in steps S 15, S 16, S 17 and the The transmission lever 26 and the continuously variable transmission 3 are held at their operation positions (transmission positions) in balance with the return biasing force to the neutral stop region N described above.

In this case, when the holding current A2 on the normal rotation side (or the reverse rotation side) is supplied to the electric motor 23, the value of the shift lever 26 and the continuously variable transmission 3 is determined by experiments or the like. The values of the holding currents A2 'and A2''which have been grasped in advance are predetermined values B' and B ''. In the forward rotation (or reverse rotation) holding currents A2 'and A2''supplied to the electric motor 23, as shown in FIG. 11, the holding current A2 in a small range C including the predetermined values B' and B ''. ',
The value of only A2 ″ is (the holding current A out of the small range C).
The values of 2 ′ and A2 ″ are ignored) and are detected by feedback, and the holding currents A2 ′ and A2 ″ on the normal rotation side (or reverse rotation side) are maintained at the predetermined values B ′ and B ″. As a result, the ratio (T ′ / T ″) between the output time T ′ and the stop time T ″ in the pulse signals P2 ′ and P2 ″ is automatically changed by the control device 31.

When the speed change lever 26 is operated in the neutral stop region N and is within the third set time T3 (for example, 200 msec) after the speed-up operation in the start region Nb (step S18), the operation current A1 to the electric motor 23 (step S18). The supply system of the holding current A2) is set to the cut-off state, and the electric motor 23 enters the idling state (step S19). The idling state of the electric motor 23 is set by exciting one of the first electromagnetic relay 32 and the second electromagnetic relay 33 shown in FIG. 6 and not outputting the pulse signals P1, P2 ′, and P2 ″ to the transistor 37. I do. In general, the belt continuously variable transmission has a large neutral region N and takes a little time from the start of the speed increase operation to the start. However, the idle start of the electric motor 23 as described above allows the operator to smoothly start. Can give an impression.

If the speed change lever 26 is operated in the neutral stop region N and the speed is not increased within the third set time T3 in the start region Nb (step S18), the operation current A1 (the holding current A2) to the electric motor 23 is maintained. ', A2'') is set in a short-circuited state (step S20). This turns off the first electromagnetic relay 32 and the second electromagnetic relay 33 shown in FIG.
Is grounded to make a short-circuited state.

[Another Embodiment] Next, another embodiment will be described. (A) In the configuration in which the potentiometer 41 detects the position of a member whose position is displaced in accordance with the shift state of the continuously variable transmission 3 to detect the shift state of the continuously variable transmission 3, the continuously variable transmission As the member whose position is displaced in accordance with the shift state of No. 3, various members other than the sector gear 22 exemplified in the above embodiment can be applied, and for example, the cam member 20 may be applied. In the case of the cam member 20, the rotation angle of the axis may be detected.

(B) The specific value of the minimum vehicle speed during the automatic shift and the specific value of the lower limit set value are not limited to the values exemplified in the above embodiment, but can be changed as appropriate. It is.

(C) In the above-described embodiment, the case where the load on the engine 1 is detected based on the number of revolutions thereof is exemplified. However, for example, the load may be detected based on the torque of the engine 1 or the like. The specific configuration of the engine load detecting means 50 can be variously changed.

(D) Instead of the electric motor 23, for example, a driving mechanism using a driving force of a hydraulic motor or an engine can be applied.

(E) In the above embodiment, the case of a belt-type continuously variable transmission is exemplified as the continuously variable transmission. However, the present invention is not limited to this. The present invention can be applied to any other continuously variable transmission, such as a shift operation unit of a hydrostatic continuously variable transmission, as long as it is activated and the operation is assisted by the drive operation means.

[Brief description of the drawings]

FIG. 1 is a side view of the vicinity of a continuously variable transmission, a shift lever, and an electric motor.

FIG. 2 is a longitudinal rear view of the continuously variable transmission.

FIG. 3 is a plan view of a cam member for gear shifting operation in the continuously variable transmission.

FIG. 4 is a schematic diagram showing a transmission system of the combine.

FIG. 5 shows a lever guide.

FIG. 6 is a diagram showing a control circuit system of the electric motor.

FIG. 7 is a diagram showing a control flow at the time of a shift operation by a shift lever.

FIG. 8 is a diagram showing a flow of control at the time of a shift operation by a shift lever.

FIG. 9 is a diagram showing a flow of control at the time of a shift operation by a shift lever.

FIG. 10 is a diagram showing a control flow at the time of a shift operation by a shift lever.

FIG. 11 is a diagram showing states of a pulse signal, an operation current supplied to the electric motor, and a holding current.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 engine 3 continuously variable transmission 8 reaping device 20 transmission unit 26 transmission operation device 31A vehicle speed control unit 31B traction control unit 41 potentiometer 45 transmission mechanism 46 threshing device 47 grain detection unit 49 switching state detection unit 50 engine load detection unit 52 command unit

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ identification code FI F16H 59:14 F16H 59:14 63:06 63:06 (58) Investigated field (Int.Cl. ⁷ , DB name) F16H 59 / 00-61/12 F16H 61/16-61/24 F16H 63/40-63/48 F16H 9/00 A01D 69/00

Claims (4)

(57) [Claims] 1. A speed change device which is artificially operated in a forward / reverse direction,
An engine load detecting unit mechanically linked to a transmission unit of the continuously variable transmission for traveling, the engine load detecting unit detecting an engine load, and the engine load is set based on detection information of the engine load detecting unit. Vehicle speed control means for executing automatic shift control for automatically shifting the continuously variable transmission so as to be maintained at a target load; command means for instructing the vehicle speed control means to execute the automatic shift control; A speed change state detecting means for detecting a speed change state of the continuously variable transmission; and a vehicle speed when the speed change state detecting means detects a speed change state for control stop irrespective of an execution command of the automatic speed change control by the command means. A vehicle speed control device for a work vehicle provided with a check means for executing a check control for controlling execution of the automatic shift control by a control means, wherein the shift state detection means and Te, said potentiometer being equipped to be operated with the shift operation of the continuously variable transmission is provided, said restraint means, on the basis of the detection value of the potentiometer is configured to perform the check control , threshing apparatus and cutting apparatus set is driven by the engine
Vignetting, heat the power from the engine is transmitted to the threshing device
Between the active state and the release state where power transmission is released.
Switching state detection to detect the existing transmission mechanism and the switching state of the transmission mechanism
Output means, and a cereal stalk that detects a planted cereal stalk that is cut by the cutting device
Detecting means is provided, and the check means is provided with the solution by the switching state detecting means.
When the removal state is detected, and in the cereal stem detection means
The above-mentioned restraint control is executed even when no planted cereal stem is detected.
A vehicle speed control device for a working vehicle configured to 2. A speed change device which is manually operated in a forward / reverse direction,
Mechanically linked to the transmission section of the continuously variable transmission for traveling.
Is, an engine load detecting means for detecting a load of the engine, based on the detection information of the engine load detecting means, wherein
The engine load is maintained at the set target load
Automatic shift control for automatically shifting the continuously variable transmission.
Vehicle speed control means to be executed, and instruct the vehicle speed control means to execute the automatic shift control.
Command means for instructing the continuously variable transmission, and a shift state detecting means for detecting a shift state of the continuously variable transmission.
And the speed of the automatic transmission control executed by the command means.
However, the shift state detecting means is not in the shift state for stopping the control.
Is detected by the vehicle speed control means.
Checking means for executing check control for checking execution of shift control
A vehicle speed control device for a working vehicle provided with, as the shifting state detecting means, the shift of the continuously variable transmission
Potentiometer equipped to be operated with operation
And the check means is provided on the basis of the detected value of the potentiometer.
And the vehicle speed control means executes the automatic shift control to the deceleration side.
During the operation, the detection value of the potentiometer
When reaching the lower limit set value on the high-speed side than the corresponding value,
Until the target load is detected by the engine load detection means.
Then, the automatic shift control is interrupted, and the lower limit set value is changed.
Configured to operate the continuously variable transmission to maintain
Speed control device of the working vehicle being used. 3. The speed change operation device which is artificially operated forward and reverse,
Mechanically linked to the transmission section of the continuously variable transmission for traveling.
Is, an engine load detecting means for detecting a load of the engine, based on the detection information of the engine load detecting means, wherein
The engine load is maintained at the set target load
Automatic shift control for automatically shifting the continuously variable transmission.
Vehicle speed control means to be executed, and instruct the vehicle speed control means to execute the automatic shift control.
Command means for instructing the continuously variable transmission and a shift state detecting means for detecting a shift state of the continuously variable transmission.
And the speed of the automatic transmission control executed by the command means.
However, the shift state detecting means is not in the shift state for stopping the control.
Is detected by the vehicle speed control means.
Checking means for executing check control for checking execution of shift control
A vehicle speed control device for a working vehicle provided with, as the shifting state detecting means, the shift of the continuously variable transmission
Potentiometer equipped to be operated with operation
And the check means is provided on the basis of the detected value of the potentiometer.
And a threshing device and a mowing device driven by the engine are configured to execute the restraint control.
Vignetting, heat the power from the engine is transmitted to the threshing device
Between the active state and the release state where power transmission is released.
Switching state detection to detect the existing transmission mechanism and the switching state of the transmission mechanism
Output means, and a cereal stalk that detects a planted cereal stalk that is cut by the cutting device
Detecting means is provided, and the check means is provided with the solution by the switching state detecting means.
When the removal state is detected, and in the cereal stem detection means
The above-mentioned restraint control is executed even when no planted cereal stem is detected.
When the detected value of the potentiometer reaches a lower limit set value on a higher speed side than a value corresponding to a stopped state during execution of the automatic shift control to a deceleration side, Until the engine load detecting means detects the target load, the automatic transmission control is interrupted and the continuously variable transmission is operated so as to maintain the lower limit set value . Vehicle speed control device. 4. The vehicle speed control device according to claim 1, wherein the continuously variable transmission is a belt-type continuously variable transmission.