JPH1038077A - Operation assist device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To certainly position and hold an operating tool regardless of a status of operating reaction force on an operated object at the time of operation stop and change of a resistance value, etc., on an electric system against an electric motor. SOLUTION: When an operating tool 26 to be manually and reciprocally operated is detected to be operated, assist force is given by an electric motor 23 toward its operating direction, and when it is detected not to be manually operated in accordance with detection information of a potentiometer 33 to detect an operating position of the operating tool 26, a holding electric current is supplied to the electric motor 23 to interrupt movement of an operated object by operating reaction force. When it is discriminated that the operating position of the operating tool 26 moves in a direction where the operating reaction force of the operated object works in a state where the holding electric current is supplied, the holding electric current flowing in the electric motor 23 is changed over to the large side, and when it is discriminated that the operating position of the operating tool 26 moves in an opposite direction of the direction where the aforementioned operating reaction force works, the holding electric current is changed over to the small side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an operation tool which is artificially operated, and an electric motor which is mechanically connected to an object to be operated and which provides an assisting force along the operation direction of the operation tool. Control means for controlling the operation state of the electric motor, and whether or not the operating tool is operated artificially, and operation state detection means for detecting the operation direction, the control means, the control means, When it is detected based on the detection information of the operation state detecting means that the operation tool is artificially operated, an assist operation is performed on the electric motor so that an assist force is applied in the artificial operation direction. The present invention relates to an operation assist device configured to supply a current.

[0002]

2. Description of the Related Art An operation assist device having the above-described structure is configured to operate an operation target such as a continuously variable transmission for traveling a vehicle body based on an artificial operation. The assisting force of the electric motor is applied in the direction, so that the manual operation can be easily performed.

In this type of operation assist device, if an operation reaction force (return biasing force) is generated in a predetermined direction on the operation target in a state where the manual operation by the operation tool is stopped, Due to such an operation reaction force, there is a possibility that the operating tool interlockingly connected to the operation target moves and the setting operation position thereof changes.

Therefore, conventionally, for example, an assisting force is provided through a worm gear type transmission mechanism that cannot rotate the rotating force of the electric motor from the driven side in an interlocking manner, or an operating tool is provided. When an assisting force is applied to the linking mechanism between the operating object and the operated object via the friction holding mechanism, even if the operating reaction force is generated from the operated object, the operating reaction force is reduced. It was configured not to be transmitted to the operation tool side.

[0005]

However, according to the above-mentioned conventional structure, for example, when the operating tool is manually operated when the electric motor fails and becomes inoperable, a worm gear type transmission mechanism is interposed. In such a case, there is a disadvantage that the operation cannot be performed because the operation is restrained by the worm gear type transmission mechanism. Further, in the configuration in which the friction holding mechanism is interposed, it is necessary to perform an artificial operation against the friction holding force, and the friction holding force is applied in addition to the operation reaction force of the operated object, and these large reaction forces are applied. However, there is a disadvantage that the operation becomes heavy and the operation becomes heavy.

In this type of assist device, even when the control means controls the electric motor to supply a set current to the electric motor, for example, the electric motor of the electric motor itself is caused by a change in temperature. There is a possibility that the resistance value may change or the electrical resistance at the wiring connection portion may change due to aging or the like. Particularly, when the current value is controlled to be low, such a resistance value change may occur. As a result, the actual supply current to the electric motor may be different from the control target value. Incidentally, it is also conceivable that the operation reaction force of the operated object changes depending on the use situation.

The present invention has been made in view of such a point, and an object thereof is to appropriately maintain a position while a manual operation is stopped while eliminating a special mechanism for maintaining the position. Even if the electric motor does not operate due to an abnormal operation or the like, it is possible to perform the artificial operation with the lightest possible operation force, and when the operation is stopped, An object of the present invention is to provide an operation assist device capable of reliably holding the position of the operation tool regardless of the state of the operation reaction force in the above or a change in the resistance value of the electric system with respect to the electric motor.

[0008]

According to the first aspect of the present invention, when it is detected that the operating tool is not artificially operated based on the detection information of the operation state detecting means,
A holding current of a preset value is supplied to the electric motor to prevent the operated object from moving due to the operation reaction force, and the operation reaction force of the operated object and the driving torque by the holding current of the electric motor are reduced. The operating position is maintained in a balanced manner.

Therefore, since the operation position is held by using the driving torque of the electric motor, a special holding mechanism for holding the operation position against the operation reaction force as described above is provided. In addition to being unnecessary, for example, it is also possible to artificially operate the electric motor with a light operating force as much as possible without operating.

In addition, an operating position detecting means for detecting the operating position of the operating tool is provided, and when the holding current is supplied, the operating position of the operating tool is determined based on the detection information of the operating position detecting means. When it is determined that the operated object has moved in the direction in which the operation reaction force acts, it is determined that the holding current is small, and the control is performed so that the holding current flowing to the electric motor is changed to the large side. When it is determined that the operation position of the operating tool has moved in the direction opposite to the direction in which the operation reaction force of the operation target acts, the holding current flowing through the electric motor whose driving current is too large due to the holding current is determined. Changed to small side.

That is, in the operation stop state, when the holding current of the set value is supplied, the balance between the operation reaction force of the operated object and the driving torque of the electric motor by the holding current is broken. When it is detected that the operating position of the operating tool is shifted from the initial position of holding, the holding current is adjusted so as to prevent such a position shift and return to the above-mentioned equilibrium state.

As a result, an appropriate holding current that can always be balanced with the operation reaction force is supplied to the electric motor, and when the manual operation is stopped, the operation position of the operation tool, ie, the operation of the operation target, is stopped. The position can be securely held.

According to a second aspect of the present invention, there is provided a current detecting means for detecting a value of an actual current flowing through the electric motor. While monitoring the detection information of the detection means, that is, the actual current detection value for the electric motor, the control is performed so that the holding current always becomes a preset value.

Therefore, for example, even when the electric resistance value in the electric system of the electric motor changes, the holding current can always be maintained in an appropriate state. Can reliably hold the operation position of the operation target.

According to a third aspect of the present invention, the object to be operated is a shift portion of a belt-type continuously variable transmission for traveling a vehicle body, and the operating tool is a shift operation of a belt-type continuously variable transmission. Is what you do.

Accordingly, the traveling speed of the vehicle body can be shifted by manipulating the operating tool, and even if the operating tool is stopped at a position of an arbitrary speed, the belt can be moved toward the neutral position in the belt-type continuously variable transmission. The position can be reliably held at the shift position against the return biasing force (operation reaction force).
Even if the electric motor becomes inoperable,
It is possible to perform a gear shift operation by manually operating the operating tool with a relatively light operating force.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A case where an operation assist device according to the present invention is applied to a belt-type continuously variable transmission will be described below with reference to the drawings. FIG. 4 shows a transmission system of a combine, which is an example of a work vehicle. Power from an engine 1 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. Is transmitted. The power from the continuously variable transmission 3 is transmitted to the transmission case 5
Is transmitted to the left and right crawler traveling devices 6 via a hydraulic clutch type forward / reverse switching device (not shown) and a traveling gear transmission (not shown). The power separated from immediately before the gear transmission is transmitted from the transmission case 5 via the belt transmission mechanism 7 to the reaping unit 8 at the front of the machine body.

Next, the belt-type continuously variable transmission 3 and its shift operation structure will be described. As shown in FIG. 2, the first split pulley 1 is attached to an input shaft 9 to which the input pulley 4 is fixed.
1. A second split pulley 12 is provided on the output shaft 10, and a transmission belt 13 is wound around the first and second split pulleys 11 and 12. The first and second split pulleys 11 and 12 include a pulley portion 14 fixed to the input shaft 9 and the output shaft 10 by a spline structure, and a pulley portion 1 movable in the axial direction.
The pulley portion 15 on the moving side of the second split pulley 12 is urged by the spring 16 toward the pulley portion 14 on the fixed side, and moves in proportion to an increase in the load on the output shaft 10 side. Side pulley portion 15 is fixed side pulley portion 14
Is provided with a cam mechanism 17 for pushing.

A ring member 18 is externally fitted to the moving pulley portion 15 of the first split pulley 11 via a bearing.
A pair of pins 18a fixed to the ring member 18 enter the recess 19 on the case side of the continuously variable transmission 3, and 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. Are formed on the cam member 20, and the rollers 18 b of the pins 18 a of the ring member 18 enter the pair of recesses 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 moving pulley portion of the second split pulley 12 In this state, the portion 15 is at the lowest speed position closest to the pulley portion 14 on the fixed side. When the cam member 20 is rotated right and left from this state, the pulley portion 15 on the moving side of the ring member 18 and the first split pulley 11 is pushed through the inclined surface 20b toward the pulley portion 14 on the fixed side. And the transmission belt 13 at the first split pulley 11
Winding radius increases. Along with this, the pulley portion 15 on the moving side of the second split pulley 12 moves away from the fixed pulley portion 14 to the right in the drawing, and the continuously variable transmission 3 is shifted to a higher speed.

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 an operation tool) that is manually operated is supported. That is, the cam member 20 as the transmission portion
Are linked via a mechanical link mechanism so as to move integrally with the shift lever 26, and are configured to be operable in forward and reverse directions.

The speed change lever 26 is swingably movable in the cross direction, and forms a forward speed change guide groove 27a, a reverse speed change guide groove 27c, and an operation state switching step portion of the lever guide as shown in FIG. Intermediate guide groove 27b
Guide groove 2 for forward gear shifting
7a or the reverse transmission guide groove 27c, when operated along the deceleration side operation direction (operation toward the neutral position side), the forward transmission guide groove 27a and the reverse transmission guide groove 2
At the inner edge k of 7c, the shift lever 26 is forcibly received and restricted at a position corresponding to the traveling neutral state, and is configured so as not to be switched to the traveling state in the reverse direction by excessive operation.

The pin 25 of the arm 25a of the ring member 25
b enters the opening 22a of the sector gear 22, and a pair of rubber-like pressure-sensitive switches 28 and 29 are connected to the arm 25a.
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 the forward position, the reverse position, and the neutral stop position is provided, and the sector gear 22 and the switching valve are connected via the push-pull wire 30 and the accommodating mechanism 31. Are linked.

A potentiometer 33 (an example of an operation position detecting means) is mounted on the fixed wall 32 on the side of the continuously variable transmission 3, and a lateral pin 34a on the tip side of a swing lever 34 extending from the potentiometer 33 is connected to the sector gear. 2
2 through the elongated hole 22b formed in the
, That is, the operating position of the shift lever can be detected.

As shown in FIG. 6, a control means H for controlling the operation of the electric motor 23 includes a control unit 35 as a control unit for instructing control information for the electric motor 23, and control information from the control unit 35. Based on the electric motor 23
Circuit 36 as a drive unit for supplying a current to and driving the
It is comprised including. The control device 35 includes a microcomputer, and is configured to execute predetermined control based on various types of input information using a control program set and stored in advance. The drive circuit 36 is switched to a forward drive state by control information from the control device 35 (that is, the shift lever 26 is switched so as to swing to the forward rotation side which is counterclockwise in FIG. 1). (Operated) The first electromagnetic relay 37 is switched to the reverse drive state (ie, the shift lever 26 is switched so as to swing clockwise in FIG. 1 to the reverse direction). The electromagnetic relay 38, the first and second electromagnetic relays 37,
38, transistors 39 and 40 for excitation drive, a current adjustment transistor 41 for adjusting the amount of current supplied to the electric motor 23 based on a control signal from the control device 35, and an actual current value flowing through the electric motor 23 at both ends. A reference resistor 42 detected as a voltage value, a smoothing circuit 43 for converting a voltage between both ends of the reference resistor 42 into a DC signal, and an electric motor 23 when an overload current continues for a set time or more in the electric motor 23.
An overload alarm circuit 44 and the like for interrupting the supply of current to the controller and inputting an alarm signal to the control device 35 are provided. As described above, the control device 35 for executing the control operation and the drive circuit 36 for adjusting the large current flowing through the electric motor 23 are separately provided.

The reference resistor 42 and the smoothing circuit 43 constitute a current detecting circuit 45 as current detecting means. The current detecting circuit 45 detects a current value in a detection range of 0 to 5 amps. Is configured.
The detection value (voltage value) of the potentiometer 33 is input to the control device 35 as an analog signal. The analog signal has a full stroke range (0.2 volt to 4.8 volt) with a resolution of 256 bits. The signal is converted from analog to digital and used for control.

To the control device 35, the detection values of the pressure-sensitive switches 28 and 29 and the potentiometer 33 are inputted, and a vehicle speed sensor 46 for detecting the traveling vehicle speed based on the rotation speed of the axle of the traveling device 6; Further, a detection value of the engine speed sensor 47 for detecting the engine speed is also input.

When one of the pressure-sensitive switches 28 and 29 is turned ON, the control device 35
When it is detected that is artificially operated in either the forward or reverse direction, an assist operation current is supplied to the electric motor 23 so that an assist force is applied in the artificial operation direction. The speed change operation can be performed lightly by the assist of the electric motor 23. Accordingly, the pressure-sensitive switches 28 and 29 constitute an operation state detecting means. Also, each pressure-sensitive switch 28,
When it is detected based on the detection information of 29 that the shift lever 26 is not operated artificially, in order to prevent the continuously variable transmission 3 from changing the shift state due to the return biasing force to the neutral position, It is configured to supply a holding current to the electric motor 26. Further, each pressure-sensitive switch 28,
The supply amount of the holding current is adjusted to an appropriate value based on the detection information of 29 and the detection information of the current detection circuit 45. Specifically, the assist operation current is O
A constant voltage is output so as to maintain the N state, and in the supply state of the holding current, the ON / OFF state of the current adjusting transistor 41 is intermittently repeated with a pulse voltage.
The ON time is adjusted (duty ratio control) to adjust the amount of current. The forward and reverse operation directions of the electric motor 26 are determined by turning on each of the pressure-sensitive switches 28 and 29 so that one of the electromagnetic relays 37 and 38 is switched to the power supply state and the rotation direction of the electric motor 26 is changed. It is stipulated.

Next, the control operation of the control device 35 will be described with reference to the control flowcharts of FIGS. Note that this control flowchart is repeatedly executed once every 10 msec. Further, when the shift 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 26 is operated. When the operation is performed in the reverse range from the other end of the neutral stop region N, the forward / reverse switching device is operated to the reverse position by the push-pull wire 29 and the switching valve.

First, it is determined whether or not the engine speed is 500 rpm or more, that is, whether or not the engine 1 is rotating normally, based on the detection state of the engine speed sensor 47 (step 1). This is because the speed change operation of the belt continuously variable transmission 3 becomes extremely heavy when the engine 1 is not rotating. With the engine 1 running,
When the shift lever 26 is operated and starts operating in the normal rotation side,
If the pressure-sensitive switch (forward switch) 28 on the normal rotation side is pressed by the pin 25b to be turned on (step 2), the operation on the reverse rotation side is terminated and 200 msec unless it is in an area where hunting may not occur. If the above has elapsed, the assist operation current is supplied to
Is driven to the normal rotation side at a high speed (steps 3, 4, 5).
Also, the pressure sensing switch (reverse rotation switch) 29 on the reverse rotation side is ON.
Then, similarly, the electric motor 26 is driven at a high speed to the reverse rotation side (steps 10 to 13). As shown in FIG. 5, near both ends of the operation area of the shift lever 26 and near the contact portion k at the neutral position N, the shift lever 26 may contact the inner edge of the guide groove and cause hunting. Therefore, in such a hunting area, the pressure-sensitive switch is turned on.
After the last reverse operation is completed,
c, the pressure-sensitive switch is
The electric motor 26 is operated at a very low speed until the FF is performed (steps 3, 6, 7, 8, and 11, 1).
4, 15, 16).

Then, a state in which the shift lever 26 is not operated (a state in which all the sensing switches are OFF).
Then, based on the detection value of the potentiometer 33,
It is determined whether the current operation position is in the forward movement range F or the reverse movement range R (step 18). 38 together with the electric motor 26
Are kept grounded (step 19,
20) If the vehicle is in the reverse drive range R, 1
Until the time of 00 msec elapses, each electromagnetic relay 37,
38 are both set to the ground side, and both terminals of the electric motor 26 are maintained in a state of being grounded (steps 21 and 22). When the reverse rotation operation is being performed in the forward movement range F, the electric motor 26 is assisting in the same direction as the direction of the return biasing force of the continuously variable transmission 3, and it is assumed that the holding current is immediately supplied from this state. This is because the supply current to the electric motor 26 may be reversed, and the electromagnetic relays 37 and 38 may rotate in the reverse direction while the current is being supplied, causing a contact failure.
In addition, when such a reverse rotation of the current occurs in the reverse drive range, there is a possibility that the above-mentioned contact abnormalities of the electromagnetic relays 37 and 38 may occur, and a shock may be applied to the speed change lever 26 in a reverse direction. This is because there is a possibility that the amount of the chromium is reduced. In addition, since the vehicle travels at a higher speed in the forward traveling region than the reverse traveling side, the traveling load is large, and the time during which the shift lever 26 is moved due to a response delay during the above-mentioned time is reduced.

After the elapse of the time, a holding current is supplied to the electric motor 26 so as to be held at the current shift position against the neutral return force of the continuously variable transmission 3,
Control is performed such that the holding force by the electric motor 26 and the neutral return force of the continuously variable transmission 3 are held in a balanced state. Since the above-described neutral return force changes depending on the shift state, a different holding force is initially set in accordance with the shift state, and based on the detection state of the potentiometer 33 and the detection state of the current detection circuit 45, The holding current is adjusted to have an appropriate value.

More specifically, the potentiometer 3
3 based on the detection value of the vehicle speed sensor 46 and the detection value of the vehicle speed sensor 46, "forward low speed", "forward high speed", "forward high speed", "reverse",
6 of "body stop in forward area" and "body stop in reverse area"
Divided into two shift states, and according to each shift state,
Initially, different holding forces (specifically, the duty ratio of the pulse applied to the current adjusting transistor 41) are set (step 23). When the vehicle is at the upper limit position of the forward movement range F, it is increased to a value larger than the initial set value by a set amount (steps 24 and 25).

The holding operation is performed with the holding force (duty ratio) set in this manner, and the value of the holding current detected by the current detection circuit 45 is calculated as a moving average value of the past four times ( Steps 26 and 27). This calculation is performed every time the control routine is executed, that is, every 10 msec.

200 ms after the holding current is started to be supplied
When ec or more has elapsed, the lever position at that time, that is,
The lever position (specifically, the detected value of the potentiometer 33) when the holding is started is stored (steps 28 and 2).
9, 30), the detection information of the potentiometer 33,
In addition, holding power control based on the detection information of the current detection circuit 45 is executed. After the stored value is once stored, the storing operation is not executed until the assist operation is executed and the flag is reset (steps 9, 17, 29, 31).

Next, the holding force control will be described. This holding force control is performed under the conditions that the engine speed is 2000 rpm or more, the detection value Ix detected by the current detection circuit 45 is not less than the set value Is, and the electric motor 26 is operating normally. (Steps 32 and 33). Moving average value I _AV of the holding current, exceeds an allowable upper limit value I _MAX, which is set in advance based on experiments or the like, the first counter N
a is counted up (+1) (steps 34 and 3).
5). When the moving average value I _AV falls below an allowable lower limit value I _MIN set in advance based on experiments or the like, the second counter N
b is counted up (steps 36 and 37). If the value does not exceed the allowable upper limit value _IMAX and does not fall below the allowable lower limit value _IMIN , each counter is counted down (-1) (step 38). If the count value of the first counter Na exceeds “100” and the current duty ratio is within a preset adjustable range, it is determined that the holding current is insufficient, and the holding force is increased. (Steps 39, 40, 4)
1). Also, the count value of the second counter Nb is "100".
Is exceeded and the current duty ratio is within the preset adjustable range, it is determined that the holding current has been exceeded, and the duty ratio is reduced by the set unit amount so that the holding force is reduced (step 42, 43, 44). Since the counting operation of each counter as described above is executed every 10 msec, the holding force is changed every second when the count value reaches “100” if the holding current excessive state or shortage state occurs continuously. The adjustment is performed, and if it occurs intermittently, the change adjustment interval until the count value becomes “100” is longer than one second.

Next, when the detected value of the potentiometer 33 is reduced by 20 points (20/256) or more (forward deceleration) from the stored value at the start of holding while the shift lever 26 is in the forward range F, In addition, when the belt continuously variable transmission 3 is moved in the direction in which the neutral return biasing force acts, the holding force is insufficient when the position is increased by 20 points or more (reverse deceleration) in the state of being in the reverse region R. If the holding force is smaller than the initial set value at that time, it is returned to the initial set value to increase the holding force, and if the holding force is larger than the initial set value, the duty is increased so that the holding force is increased. Increase the ratio by the set unit amount (step 45,
47, 49, 50, 51). When the shift lever 26 is in the forward movement range F, the detection value of the potentiometer 33 is 5 points (5/25) from the stored value at the start of holding.
6) When it increases by more than one (forward acceleration) and when it decreases by more than 5 points (reverse acceleration) in the reverse range R,
In other words, when the belt continuously variable transmission 3 moves in the direction opposite to the direction in which the neutral return biasing force acts, it is determined that the holding force is excessive, and the holding force at that time is set to the initial set value. If it is larger than the initial setting value, the holding force is reduced by reducing the holding ratio. If the state is smaller than the initial setting value, the duty ratio is reduced by the set unit amount so that the holding force decreases (steps 46, 48, 52, 53). , 54). When the duty ratio is changed, the detection value of the potentiometer 33 at that time is set to a new value at the start of holding (stored value).
(Step 55).

[Other Embodiments] (1) In the above embodiment, when the lever position (operation position) changes by a set amount or more during the holding operation, the holding force (holding current) is changed and adjusted. However, instead of such a control configuration, the lever position is sequentially compared with the previous value, and if there is a change, control is performed to change the holding force by a unit amount so as to prevent the change. It may be a configuration.

(2) In the above embodiment, when a state where the average value of the actually measured values of the holding current exceeds the allowable upper limit value I _MAX or falls below the allowable lower limit value I _MIN is detected for the set number of times or more ( For example, when the holding force is changed for one second), the holding force is changed. However, instead of such a structure, the following structure may be used. The control may be performed sequentially so that the detected value of the holding current always becomes a current value corresponding to the holding force adjustment value based on the lever position.

(3) In the above embodiment, the potentiometer as the operation position detecting means detects the operation amount of the sector gear 22, but the operation amount of the shift lever 26,
The operation amount of the cam member 20 may be directly detected, or the movement amount of the member in the link mechanism may be detected.

(4) In the above embodiment, the case where the belt-type continuously variable transmission 3 is shifted as an object to be operated has been exemplified. However, the present invention is not limited to the belt-type continuously variable transmission 3, but may be a hydraulic type continuously variable transmission 3. The present invention may be applied to an operation structure of a continuously variable transmission and other continuously variable transmissions. The operation target is not limited to the continuously variable transmission, and for example, a configuration in which a working device is manually lifted and lowered by an operating tool. The present invention can be applied to various operation configurations such as a configuration in which an assist operation is performed by the electric motor 26 by using the motor.

[Brief description of the drawings]

FIG. 1 is a side view showing a shift operation configuration.

FIG. 2 is a sectional view of the belt continuously variable transmission.

FIG. 3 is a side view of the cam mechanism.

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

FIG. 5 is a diagram showing an operation range of a shift lever.

FIG. 6 is an electric circuit block diagram.

FIG. 7 is a flowchart of a control operation.

FIG. 8 is a flowchart of a control operation.

FIG. 9 is a flowchart of a control operation.

FIG. 10 is a flowchart of a control operation.

FIG. 11 is a flowchart of a control operation.

FIG. 12 is a flowchart of a control operation.

[Explanation of symbols]

 Reference Signs List 3 continuously variable transmission 20 transmission section 23 electric motor 26 operating tool 28, 29 operating state detecting means 33 operating position detecting means 45 current detecting means H controlling means

Claims (3)

[Claims] An electric motor that is mechanically linked with an operation tool that is artificially operated and an operation target, and that provides an assist force along an operation direction of the operation tool, and an operation state of the electric motor. And operation state detection means for detecting whether or not the operation tool is artificially operated, and an operation direction thereof, wherein the control means detects the operation state detection means. Based on the information, when it is detected that the operation tool is artificially operated, so that an assist force is given in the artificial operation direction,
An operation assist device configured to control an assist operation current to be supplied to the electric motor, comprising: an operation position detection unit configured to detect an operation position of the operation tool. When it is detected based on the detection information of the operation state detecting means that the operating tool is not artificially operated, the electric motor is controlled in advance to prevent the operated object from moving due to an operation reaction force. Controlling the holding current of the set value to be supplied, and, in a state where the holding current is being supplied, based on the detection information of the operation position detecting means, the operation position of the operating tool, When it is determined that the operation target has moved in the direction in which the operation reaction force acts, the holding current flowing through the electric motor is controlled to change to a large side, and the operation position of the operation tool is When it is determined that the object to be operated has moved in the direction opposite to the direction in which the operation reaction force acts, an operation configured to control the holding current flowing through the electric motor to change to a small side. Assist device. A current detection unit for detecting an actual current value flowing through the electric motor, wherein the control unit detects a value of the current detected by the current detection unit in a state where the holding current is supplied. The operation assist device according to claim 1, wherein the operation assist device is configured to control the holding current to be the set value based on the current value. 3. The speed change section of a belt-type continuously variable transmission for traveling a vehicle body, and the operating tool performs a shift operation of the belt-type continuously variable transmission. The operation assist device as described in the above.