JP5249872B2 - Clutch control device and method for modifying clutch control device - Google Patents

Description

  The present invention relates to a clutch control device and a clutch control method, and in particular, a clutch control device having an inching device capable of electronically controlling an operating hydraulic pressure supplied to the clutch in response to a depression amount of an inching pedal, and The present invention relates to a modification method of a clutch control device that adds an inching function capable of electronically controlling the hydraulic pressure supplied to the clutch by simple modification.

Industrial vehicles such as forklifts or straddle carriers, or construction machinery such as motor graders, motor scrapers, bulldozers, wheel loaders, etc. are equipped with inching devices that perform inching while performing operations such as cargo handling operations. Has been.
The inching device is a device that performs traveling control to move the vehicle forward or backward at a slow speed when performing operations such as cargo handling operations, etc., improving workability in industrial vehicles, and smoothing stop, start, or direction change It is used to
In an inching device, inching travel is generally performed by controlling an inching valve by depressing an inching pedal or a brake pedal.

  FIG. 6 shows an example of a circuit diagram of a conventional forward control 1-speed / reverse-speed transmission control valve equipped with an inching device. As shown in FIG. 6, oil is sucked up from the oil tank 104 by the pump 102, and the discharge pressure of the pump 102 is regulated by the pressure regulating mechanism 106. The pressure adjusting mechanism 106 mainly includes a main relief valve 108, a cooler 110, and a second relief valve 112. The main relief valve 108 determines the upper limit of the pressure of the circuit from the pump 102 to the clutch to be described later. A part of the oil passing through the main relief valve 108 is cooled by the cooler 110 and is used as a lubricating oil circuit (Lube circuit). 114. The second relief valve is provided to adjust the hydraulic pressure supplied to the cooler 110 so that the hydraulic pressure supplied to the cooler 110 does not exceed the design pressure of the cooler.

The accumulator valve 116 is for smooth engagement of the clutch at the time of shifting. An outline of the configuration and operation of the accumulator valve 116 is as follows.
The accumulator valve 116 mainly includes a bypass circuit 116a, an operation part 116b that is operated by hydraulic pressure in the bypass circuit 116a, an orifice circuit part 116c that is provided with an orifice in the middle to connect the circuit, and a blocking part 116d that shuts off the circuit. And a connection portion 116e for connecting a circuit and a spring 116f.
The accumulator valve 116 has a high hydraulic pressure in the bypass circuit 116a during normal operation, and the operation portion 116b operates against the spring 116f, and the circuit is connected by the orifice circuit portion 116c. At this time, when the clutch is switched by the FNR lever 124 described later (for example, from forward to reverse), the hydraulic pressure in the bypass circuit 116a decreases because the circuit is connected to the clutch in which oil is empty at the moment when the clutch is switched. The resistance force of the operating portion 116b to the spring 116f is reduced, and the circuit is connected at the connecting portion 116e. By connecting the circuit at the connecting portion 116e, oil is supplied to the clutch, and the hydraulic pressure in the bypass circuit 116a also increases. As the hydraulic pressure in the bypass circuit 116a increases, the resistance of the operating portion 116b to the spring 116f also increases, and the blocking portion 116d is connected to the circuit, and the circuit is blocked. However, even when the circuit is shut off by the shutoff part 116d, the oil is gradually supplied to the clutch through the bypass circuit 116a, so that the oil is gradually filled in the clutch and the hydraulic pressure of the bypass circuit 116a also increases. . As the hydraulic pressure of the bypass circuit 116a increases, the resistance force of the operating portion 116b to the spring 116f further increases, and the circuit is connected by the orifice circuit portion 116c. This completes clutch switching.

The inching pedal 118 operates the inching valve 120 to reduce the main hydraulic pressure and enable the clutch to be released or a half-clutch state. The inching pedal 118 and the inching valve 120 are mechanically connected by a link and a push-pull cable 122 or the like.
The forward / neutral / reverse switching lever (FNR lever) 124 operates the forward switching solenoid valve 126a and the backward switching solenoid valve 126b of the FNR switching valve 126 to send main hydraulic pressure to the forward clutch or the reverse clutch. Each position is switched by draining the hydraulic pressure of both clutches.

The apparatus described with reference to FIG. 6 as described above is disclosed in Patent Document 1, for example.
However, in the apparatus described with reference to FIG. 6, the inching pedal 118 and the inching valve 120 are mechanically connected. Therefore, if the opening degree of the inching valve 120 is changed with respect to the depression amount of the inching pedal 118, parts are replaced. There is a problem that it is necessary and time-consuming.

  As a countermeasure for such a problem by mechanically connecting the inching pedal and the inching valve, a method of electronically controlling the inching valve has been adopted, and is disclosed in, for example, Patent Document 2.

JP-A-5-4606 JP-A 61-52454

  However, if the inching valve is simply electronically controlled with respect to the apparatus described with reference to FIG. 6 and an electronically controlled inching valve is employed, the forward switching solenoid valve 126a and 126b shown in FIG. In addition to the switching solenoid valve, it is necessary to provide a new solenoid valve for inching control. The cost increase due to the use of a new solenoid valve cannot be compensated for by the cost reduction due to the reduction in the links and cables that mechanically connected the inching pedal and the inching valve. And the structure becomes complicated.

Therefore, in order not to add a solenoid valve, it is conceivable that the solenoid valve of the existing FNR switching valve as shown in FIG. 6 has the function of an inching valve. However, in this case, if the FNR lever is directly connected as shown in FIG. 6, the electrical wiring for inputting the control signal at the time of inching to the solenoid valve of the FNR switching valve becomes complicated.
Therefore, in an apparatus in which the existing FNR lever is directly connected to the solenoid valve of the FNR switching valve, it is difficult to modify the inching function at low cost so as to be electronically controlled.

  Therefore, in view of the problems of the prior art, the present invention is a clutch control device in which the inching function can be electronically controlled with a simple structure and the existing FNR lever is directly connected to the solenoid valve of the FNR switching valve. The present invention also provides a clutch control device and a clutch control device remodeling method that can be easily modified so that the solenoid valve of the FNR switching valve has an inching valve function and the inching function is electronically controlled. With the goal.

  A forward / reverse switching valve that selectively supplies hydraulic oil to either the forward or reverse side of the clutch in the hydraulic oil passage to the clutch, and an operating hydraulic pressure that is supplied to the clutch in accordance with the depression amount of the inching pedal A control switch for a clutch in a transmission having an inching device capable of controlling the control, a selection switch capable of selecting whether to supply hydraulic oil to the forward side or the reverse side, and the selection switch and the forward / reverse switching valve A forward / reverse switching valve that operates when supplying hydraulic fluid to the forward side of the clutch, and hydraulic oil to the reverse side of the clutch. A reverse solenoid valve that is actuated when supplying the forward switch, and the relay is electrically connected to the forward side of the selection switch. A forward relay comprising a forward switch electrically connected to the side coil and the forward solenoid valve; a reverse coil electrically connected to the reverse side of the selection switch; and the reverse solenoid valve. The inching device is configured to be able to supply a current corresponding to the depression amount of the inching pedal to the forward side switch and the reverse side switch. The selection switch is for supplying a current to the forward side coil or the reverse side coil when either the forward side or the reverse side is selected, and the selection switch is set to either the forward side or the reverse side. Is selected, current flows through the forward or reverse coil, and the forward or reverse switch is turned on. On purpose made, the current from the inching device via the forward-side switch or the reverse side switch becomes the on state, characterized in that it is supplied to the forward side solenoid valve or reverse side solenoid valve.

  Accordingly, the hydraulic pressure supplied to the clutch can be electronically controlled in accordance with the amount of depression of the inching pedal using the forward solenoid valve and the reverse solenoid valve constituting the forward / reverse switching valve, that is, electronic control Inching by is possible. By using the forward solenoid valve and the reverse solenoid valve, it is not necessary to increase the number of solenoid valves as compared with the prior art, and it is possible to provide a clutch control device in which the inching function is electronically controlled with a simple structure.

  Furthermore, a forward relay and a reverse relay are interposed between the selection switch forward side and forward side solenoid valve, and the selection switch reverse side and reverse side solenoid valve, respectively. Therefore, the selector switch forward side and forward side solenoid valve, the selector switch reverse side and reverse side solenoid valve are electrically connected, and the clutch control device and inching function without inching function are machine controlled. When implementing the present invention by modifying a clutch control device, a forward relay and a reverse relay are provided, and currents corresponding to the depression amount of the inching pedal are respectively provided to the forward relay and the reverse relay. Should be able to flow. Therefore, it is possible to remodel a clutch control device in which the existing inching function is not electronically controlled to make the embodiment of the present invention very easily. Further, even an existing clutch control device in which the selector switch forward side and forward side solenoid valve and the selector switch reverse side and reverse side solenoid valve are electrically connected directly can be easily modified to the form of the present invention. Can be applied.

  The forward solenoid valve and the reverse solenoid valve are proportional solenoid valves whose opening degree changes in accordance with a supplied current value, and the inching device is proportional to the depression amount of the inching pedal. It is preferable that a current having a magnitude can be supplied to the forward switch and the reverse switch.

  By using the proportional solenoid valve, it is possible to control the hydraulic pressure supplied to the clutch in accordance with the depression amount of the inching pedal with high accuracy.

The forward solenoid valve and the reverse solenoid valve are on / off solenoid valves, and the inching device supplies a current having a pulse width corresponding to the amount of depression of the inching pedal to the forward switch and the reverse switch. It should be possible to supply.
In this case, since the proportional solenoid valve is not used but the on / off solenoid valve is used, the configuration of the solenoid valve is simple, and the cost of the entire apparatus can be reduced. Further, when modifying an existing clutch control device in which the forward solenoid valve and the reverse solenoid valve are on / off solenoid valves, the existing solenoid valves can be used as they are.

  Further, as a modification method of the clutch control device for realizing the problem, there is provided a forward / reverse switching valve for selectively supplying hydraulic oil to either the forward side or the reverse side of the clutch to the hydraulic oil path to the clutch. A selection switch that can select whether the hydraulic oil is supplied to the forward side or the reverse side to the clutch, and the forward / reverse switching valve operates when the hydraulic oil is supplied to the forward side of the clutch. A forward solenoid valve and a reverse solenoid valve that operates when hydraulic oil is supplied to the reverse side of the clutch, and the forward side of the selection switch and the forward side solenoid valve are electrically connected to each other; And a modification method of the clutch control device in which the reverse side solenoid valve of the selection switch and the reverse side solenoid valve are electrically connected, the forward side of the selection switch A forward relay having a coil and a switch is interposed between the forward solenoid valve and the forward side of the selection switch and the coil, and the forward solenoid valve and the switch are electrically connected to each other. And a reverse relay having a coil and a switch between the reverse side of the selection switch and the reverse side solenoid valve, the reverse side of the selection switch and the coil, and the reverse side solenoid valve and the switch, respectively. An electrical connection is provided, and means for enabling supply of a current corresponding to the amount of depression of the inching pedal is provided to both the forward relay switch and the reverse relay switch. .

  As described above, according to the present invention, the inching function can be electronically controlled with a simple structure, and in the clutch control device in which the existing FNR lever is directly connected to the solenoid valve of the FNR switching valve, the FNR It is possible to provide a clutch control device and a clutch control device remodeling method that can be easily remodeled so that the solenoid valve of the switching valve has an inching valve function and the inching function is electronically controlled.

It is a circuit diagram of the control valve for transmission regarding an Example. It is the circuit diagram which showed the A section in FIG. It is a circuit diagram around the existing FNR switching valve in which the FNR lever and the FNR switching valve are directly connected. 6 is a circuit diagram of a transmission control valve in Comparative Example 1. FIG. It is a circuit diagram around the existing FNR switching valve in which the FNR lever and the FNR switching valve in Comparative Example 2 are connected via an electronic control unit. It is a circuit diagram of a conventional control valve for transmission.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, but are merely illustrative examples. Not too much.

FIG. 1 is a circuit diagram of a transmission control valve according to the embodiment. First, the configuration of the hydraulic circuit in the embodiment will be described with reference to FIG.
As shown in FIG. 1, the pump 2 sucks up oil from the oil tank 4, and the pressure regulating mechanism 6 regulates the discharge pressure of the pump 2. The pressure regulating mechanism 6 is mainly composed of a main relief valve 8, a cooler 10, and a second relief valve 12, and the function thereof is the same as that of the conventional pressure regulating mechanism 106 described with reference to FIG. Therefore, explanation is omitted.

The accumulator valve 16 is for smooth engagement of the clutch at the time of shifting.
The accumulator valve 16 is mainly composed of a bypass circuit 16a, an operating portion 16b that is operated by hydraulic pressure in the bypass circuit 16a, an orifice circuit portion 16c that is provided with an orifice in the middle to connect the circuit, and a blocking portion 16d that blocks the circuit. And a connection portion 16e for connecting a circuit and a spring 16f. The function and operation are the same as those of the conventional accumulator valve 116 described with reference to FIG.

The inching pedal 18 is connected to a switch 32a of a forward relay 32 and a switch 34a of a reverse relay 34, which will be described later, via a vehicle VCM (vehicle control module) 28.
The switch 32a is electrically connected to the forward switching proportional solenoid valve 26a of the FNR switching valve 26, and the switch 34a is electrically connected to the reverse switching proportional solenoid valve 26b of the FNR switching valve 26. The switch 32a is configured so that the vehicle VCM 28 (inching pedal 18) and the forward switching proportional solenoid valve 26a are electrically connected when the switch is turned on. Similarly, the switch 34a is connected to the vehicle VCM 28 ( The inching pedal 18) and the reverse switching proportional solenoid valve 26b are electrically connected.

  The forward / neutral / reverse switching lever (FNR lever) 24 is electrically connected to a coil 32b of the forward relay 32 and a coil 34b of the reverse relay 34.

  Further, the forward relay 32 is configured such that the switch 32a is turned on when a current flows through the coil 32b, and similarly, the reverse relay 34 is configured so that the switch 34a is turned on when a current flows through the coil 34b.

  Next, control of the clutch during inching traveling in the embodiment will be described with reference to FIGS. 1 and 2. FIG. 2 is a circuit diagram showing a portion A in FIG.

  When the driver steps on the inching pedal 18, an inching opening degree sensor (not shown) detects the opening degree (the amount by which the inching pedal is depressed), and information on the opening degree is sent to the vehicle VCM 28. The inching opening sensor can be an analog sensor such as a potentiometer, for example, or a digital sensor such as an encoder.

  The vehicle VCM 28 converts the opening data of the inching pedal 18 sent from the inching opening sensor into a current value corresponding to the opening data. Then, a current corresponding to the current value is supplied as an inching signal to a switch 32a constituting the forward relay 32 and a switch 34a constituting the reverse relay 34.

  At this time, when the driver operates the FNR lever 24 to the forward side (F side in FIGS. 1 and 2), for example, an electric current flows from the outside to the coil 32 b constituting the forward side relay 32 via the FNR lever 24. When the current flows through the coil 32b, the forward side relay 32 is activated and the switch 32a is turned on.

When the switch 32a is turned on, the inching signal sent from the vehicle VCM 28 is sent to the forward proportional solenoid valve 26a constituting the FNR switching valve 26 via the switch 32a. Thereby, the opening degree of the forward proportional solenoid valve 26a is controlled according to the current value of the inching signal.
That is, by operating the FNR lever 24 forward (F side) and depressing the inching pedal 18, the opening data of the inching pedal 18 is supplied to the vehicle VCM 28, and a current corresponding to the opening is supplied to the vehicle. The opening degree is controlled by flowing from the VCM 28 to the forward proportional solenoid valve 26a via the switch 32a turned on as an inching signal. In other words, the opening degree of the forward proportional solenoid valve 26a is electronically controlled according to the opening degree of the inching pedal 18, and the hydraulic pressure corresponding to the opening degree of the inching pedal 18 is supplied to the forward side clutch to advance the vehicle at a slow speed. Control is possible, and the forward proportional solenoid valve 26a also functions as an inching valve.
At this time, the reverse relay 34 does not turn on the switch 34a because no current flows through the coil 34b via the FNR lever 24, and the inching signal from the vehicle VCM 28 is sent to the reverse proportional solenoid valve 26b. I can't.

  On the other hand, when the driver operates the FNR lever 24 to the reverse side (R side in FIGS. 1 and 2), current flows from the outside to the coil 34 b constituting the reverse side relay 34 via the FNR lever 24. When the current flows through the coil 34b, the reverse relay 34 is activated and the switch 34a is turned on.

When the switch 34a is turned on, the inching signal sent from the vehicle VCM 28 is sent to the reverse proportional solenoid valve 26b constituting the FNR switching valve 26 via the switch 34a. As a result, the opening degree of the reverse proportional solenoid valve 26b is controlled in accordance with the current value of the inching signal.
That is, by operating the FNR lever 24 to the reverse side (R side) and depressing the inching pedal 18, the opening degree data of the inching pedal 18 is supplied to the vehicle VCM 28, and a current corresponding to the opening degree is supplied to the vehicle. As the inching signal from the VCM 28 is passed through the switch 34a which has been turned on, the reverse proportional solenoid valve 26b is caused to flow and its opening degree is controlled. In other words, the opening of the reverse proportional solenoid valve 26b is electronically controlled in accordance with the opening of the inching pedal 18, and the hydraulic pressure corresponding to the opening of the inching pedal 18 is supplied to the reverse clutch to drive the vehicle backward at a slow speed. The reverse proportional solenoid valve 26b also has the function of an inching valve.
At this time, the forward relay 32 does not turn on the switch 32a because no current flows through the coil 32b via the FNR lever 24, and the inching signal from the vehicle VCM 28 is sent to the forward proportional solenoid valve 26a. I can't.

  In the embodiment, proportional solenoid valves (26a, 26b) are used for the forward side and the reverse side for the FNR switching valve 26. However, an on / off solenoid valve may be used instead of the proportional solenoid valve. When the on / off solenoid valve is used, it is necessary to control the on / off solenoid valve by PWM (Pulse Width Modulation), and a current having a pulse width corresponding to the depression amount of the inching pedal 18 is supplied from the vehicle VCM 28 to the switch 32a, 34a needs to be supplied.

  By performing the above configuration and control, the solenoid valve of the FNR switching valve has an inching valve function, and the inching function can be electronically controlled with a simple structure without increasing the number of solenoid valves.

Next, modification of existing equipment will be described with reference to FIGS. FIG. 3 is a circuit diagram around an existing FNR switching valve in which an FNR lever and an FNR switching valve are directly connected. In FIG. 3, the same reference numerals as those in FIGS. 1 and 2 have the same functions, and the description thereof is omitted.
In the circuit shown in FIG. 3, when the FNR switching lever 24 is operated to the forward side (F side), the FNR switching lever 24 and the forward proportional solenoid valve 26a constituting the FNR switching valve 26 are electrically connected, and the FNR A current flows from the outside to the forward proportional solenoid valve 26a via the lever 24, and the opening degree of the forward proportional solenoid valve 26a is adjusted according to the current value of the current. On the other hand, when the FNR switching lever 24 is operated to the reverse side (R side), the reverse proportional solenoid valve 26b constituting the FNR switching lever 24 and the FNR switching valve 26 is electrically connected, and the reverse traveling solenoid valve 26b is connected via the FNR lever 24. A current flows from the outside to the proportional solenoid valve 26b, and the opening degree of the reverse proportional solenoid valve 26b is adjusted according to the current value of the current.

  When the circuit as shown in FIG. 3 is modified to the circuit according to the embodiment of the present invention as shown in FIG. 2, the forward contact (F side) contact 24a of the FNR switching lever 24 and the forward solenoid valve 26a. Is provided between the contact 24b on the reverse side (R side) of the FNR switching lever 24 and the solenoid valve 26b for reverse drive. Then, an inching signal may be input to the switch 32a constituting the forward relay 32 and the switch 34a constituting the reverse relay 34. At this time, in the forward relay 32 and the reverse relay 34, the coils 32b and 34b are electrically connected to the contacts 24a and 24b of the FNR switching lever 24, and the switches 32a and 34a are electrically connected to the forward solenoid valve 26a and the reverse solenoid valve 26b. It is necessary to provide a connection.

  As described above, according to the present invention, it is easy to modify the existing apparatus in which the FNR lever is directly connected to the solenoid valve of the FNR switching valve so that the inching is electronically controlled.

  Next, another example capable of electronic control of inching will be described as Comparative Example 1.

[Comparative Example 1]
4 is a circuit diagram of a transmission control valve in Comparative Example 1. FIG. In FIG. 4, the same reference numerals as those in FIG. 6 shown as the conventional example have the same functions, and the description thereof is omitted.
In the circuit shown in FIG. 4, a solenoid valve 120a is provided for inching valve control, and the opening degree of the solenoid valve 120a is controlled by an inching signal (current) from the vehicle VCM 128. The inching pedal 118 and the vehicle VCM 128 have the same functions as the inching pedal 18 and the vehicle VCM 28 shown in FIG.

  With the configuration shown in FIG. 4, it is possible to electronically control the inching valve 120. However, compared with the conventional circuit in FIG. 6, it is necessary to newly provide the inching control solenoid valve 120a. The cost increase due to the use of the solenoid valve cannot be compensated for by the cost reduction by reducing the link and cable that mechanically connected the inching pedal and the inching valve. .

  Next, as another example of modification of existing equipment, a comparative example 2 will be described.

[Comparative Example 2]
FIG. 5 is a circuit diagram around an existing FNR switching valve in which an FNR lever and an FNR switching valve are connected via an electronic control unit. In FIG. 5, the same reference numerals as those in FIG. 3 have the same functions, and the description thereof is omitted.
In the circuit shown in FIG. 5, when the FNR lever 24 is operated to the forward side (F side) or the reverse side (R side), information on the operating state of the FNR switching lever 24 is sent to the electronic control unit 40. A signal (current) corresponding to is sent from the electronic control unit 40 to the forward solenoid valve 26a or the reverse solenoid valve 26b.
As shown in FIG. 5, when the existing circuit has an electronic control unit as shown in FIG. 5, information on the opening degree of the inching pedal is necessary when performing modification with the electronic control of the inching function. The electronic control unit 40 may be modified so that an inching signal (current) corresponding to the opening degree is sent from the electronic control unit 40 to the forward solenoid valve 26a or the reverse solenoid valve 26b.

In this way, when modifying the existing equipment, information on the opening of the inching pedal is sent to the electronic control unit, and the electronic control unit controls the forward solenoid valve and the reverse solenoid valve constituting the FNR switching valve. It is also possible to do. However, there is no particular problem if the existing circuit has an electronic control unit as shown in FIG. 5, but the existing circuit does not have an electronic control unit as shown in FIG. 3, for example. In some cases, it is necessary to add a new electronic control unit, which increases the cost of the entire apparatus, and is difficult to apply.
In other words, when the electronic control unit is used when the existing equipment is modified and the inching is electronically controlled, it is limited to the case where the electronic control unit is used in the existing circuit as shown in FIG. Narrow and low versatility.

  The inching function can be electronically controlled with a simple structure, and in the clutch control device in which the existing FNR lever is directly connected to the solenoid valve of the FNR switching valve, the function of the inching valve is added to the solenoid valve of the FNR switching valve. The clutch control device and the clutch control device can be easily modified so that the inching function is electronically controlled.

18 Inching pedal 24 FNR selector lever (selection switch)
26 FNR switching valve (forward / reverse switching valve)
28 Vehicle VCM
32 Forward side relay 32a Switch (forward side switch)
32b Coil (forward coil)
34 Reverse relay 34a Switch (reverse switch)
34b Coil (backward side coil)
40 Electronic control unit

Claims (4)

A forward / reverse switching valve that selectively supplies hydraulic oil to either the forward or reverse side of the clutch in the hydraulic oil passage to the clutch, and an operating hydraulic pressure that is supplied to the clutch in accordance with the depression amount of the inching pedal A clutch control device in a transmission having an inching device capable of controlling
A selection switch capable of selecting whether to supply hydraulic oil to the forward side or the reverse side to the clutch;
A relay circuit interposed between the selection switch and the forward / reverse switching valve;
The forward / reverse switching valve has a forward solenoid valve that operates when hydraulic fluid is supplied to the forward side of the clutch, and a reverse solenoid valve that operates when hydraulic fluid is supplied to the reverse side of the clutch. The relay includes a forward coil electrically connected to the forward side of the selection switch and a forward side switch electrically connected to the forward solenoid valve; and the relay of the selection switch Comprising a reverse side coil composed of a reverse side coil electrically connected to the reverse side and a reverse side switch electrically connected to the reverse side solenoid valve,
The inching device is configured to be able to supply a current corresponding to the depression amount of the inching pedal to the forward switch and the reverse switch,
The selection switch is configured to supply a current to the forward side coil or the reverse side coil when either the forward side or the reverse side is selected,
By selecting either the forward side or the reverse side of the selection switch, a current flows through the forward side coil or the reverse side coil, and the forward side switch or the reverse side switch is turned on. A clutch control device, wherein an electric current is supplied to the forward solenoid valve or the reverse solenoid valve via the forward switch or reverse switch in the ON state. The forward-side solenoid valve and the reverse-side solenoid valve are proportional solenoid valves whose opening degree changes according to a supplied current value,
2. The clutch according to claim 1, wherein the inching device is capable of supplying a current having a magnitude proportional to the amount of depression of the inching pedal to the forward switch and the reverse switch. Control device. The forward solenoid valve and the reverse solenoid valve are on / off solenoid valves,
2. The clutch control device according to claim 1, wherein the inching device is capable of supplying a current having a pulse width corresponding to a depression amount of the inching pedal to the forward side switch and the reverse side switch. The hydraulic fluid path to the clutch is provided with a forward / reverse switching valve that selectively supplies hydraulic oil to either the forward side or the reverse side of the clutch, and supplies the hydraulic oil to the forward side or the reverse side of the clutch. A forward / reverse switching valve that operates when supplying hydraulic oil to the forward side of the clutch, and supplies hydraulic oil to the reverse side of the clutch. A reverse side solenoid valve that is actuated from time to time, the forward side of the selection switch and the forward side solenoid valve are electrically connected, and the reverse side of the selection switch and the reverse side solenoid valve are electrically connected A modification method of a control device of a clutch connected to
A forward relay having a coil and a switch is provided between the forward side of the selection switch and the forward side solenoid valve, and the forward side of the selection switch and the coil, and the forward side solenoid valve and the switch are electrically connected respectively. While interposing to be connected,
A reverse relay having a coil and a switch is electrically connected between the reverse side of the selection switch and the reverse side solenoid valve, and the reverse side of the selection switch and the coil, and the reverse side solenoid valve and the switch are electrically connected, respectively. Intervening to be connected,
A method for modifying a clutch control device, characterized in that means for supplying a current corresponding to the amount of depression of an inching pedal is provided to both of the forward relay switch and the reverse relay switch.

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