Clutch control device

This clutch control device is provided with: a supply valve and a supply valve control unit, which control the supply of an operating fluid to a pressure chamber; a first discharge valve and a first discharge valve control unit, which control the discharge of the operating fluid in the pressure chamber; and a second discharge valve and a second discharge valve control unit, which control the discharge of the operating fluid in the pressure chamber. When it is determined that the engagement and disengagement switching of a clutch device 2, which is necessitated by the discharge of the operating fluid in the pressure chamber, is required, the first discharge valve is controlled to be opened and then the second discharge valve is controlled to be opened.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a U.S. National Stage entry of PCT Application No. PCT/JP2019/010466, filed on Mar. 14, 2019, which claims priority to JP Application No. 2018-050678, filed Mar. 19, 2018, The contents of the foregoing are incorporated by reference.

TECHNICAL FIELD

The present disclosure relates to a clutch control device configured to control disengagement and engagement of a clutch device by controlling supply and discharge of a working fluid to and from a clutch actuator.

BACKGROUND ART

There is known a technology in which a clutch, that is, a clutch device is arranged between an engine and a transmission mechanism, and disengagement and engagement of the clutch device is controlled so as to control transmission of a driving force between the engine and the transmission mechanism. Further, there is also known a technology of controlling disengagement and engagement of a clutch device using a fluid (working fluid) such as air or hydraulic oil.

For example, Patent Literature 1 discloses a clutch actuator for switching connection and disconnection (disengagement) of a clutch device. The clutch actuator includes an air chamber and an atmosphere chamber formed in a cylinder, and a piston movably provided in the cylinder. An elastic member is provided in the air chamber so as to push the piston against a load of the clutch. Further, two valve mechanisms corresponding to air supply valves tor allowing compressed air to flow into the air chamber, and two valve mechanisms corresponding to air discharge valves for discharging the compressed air from the air chamber are provided. By opening and closing these air supply valves and opening and closing these air discharge valves, connection and disconnection of the clutch can be switched.

CITATION LIST

Patent Literature

SUMMARY OF INVENTION

Technical Problem

In the above clutch device, in a state where the pressure of the air chamber in the cylinder is high, by opening these two valve mechanisms, the pressure in the air chamber drops rapidly, the movement of the piston occurs too early in terms of control, and eventually the movement of the piston beyond a target value thereof, that is, overshoot may occur. On the other hand, when the pressure in the air chamber decreases, the discharge of the compressed air from the air chamber becomes slow, and the responsiveness of the clutch may deteriorate.

Therefore, the technology of the present disclosure provides a clutch control device that suitably controls discharge of a working fluid from a cylinder of a clutch actuator which is for switching between disengagement and engagement of a clutch device.

Solution to Problem

A technology of the present disclosure provides a clutch control device configured to control switching between disengagement and engagement of a clutch device by adjusting an urging force of a spring member to a clutch member in the clutch device, the urging force being adjusted by controlling movement of a piston of a clutch actuator, and the clutch actuator including a pressure chamber formed in a cylinder, and the piston provided movably in the cylinder in accordance with pressure of a working fluid in the pressure chamber, the clutch control device including: at least one supply valve for controlling supply of the working fluid to the pressure chamber; a supply valve control unit configured to control operation of the at least one supply valve; a first discharge valve for controlling discharge of the working fluid in the pressure chamber; a second discharge valve for controlling the discharge of the working fluid in the pressure chamber; a first discharge valve control unit configured to control operation of the first discharge valve; a second discharge valve control unit configured to control operation of the second discharge valve; and an operation determination unit configured to perform an operation determination of the clutch device, in which when it is determined by the operation determination unit that a disengagement and engagement switching process of the clutch device by discharging the working fluid from the pressure chamber is necessary, the second discharge valve control unit performs opening control on the second discharge valve after opening control is performed on the first discharge valve by the first discharge valve control unit.

In the above clutch control device, the second discharge valve control unit may be configured to perform the opening control on the second discharge valve when pressure of the pressure chamber becomes lower than a predetermined pressure lower than the pressure of the pressure chamber when the first discharge valve is opened.

The above clutch control device may further include a stroke sensor configured to detect a stroke value of the piston. In this case, at least one of the first discharge valve control unit and the second discharge valve control unit may execute valve control in accordance with the stroke value acquired based on an output from the stroke sensor. Alternatively, the above clutch control device may further include a pressure estimation unit configured to estimate pressure of the pressure chamber. In this case, at least one of the first discharge valve control unit and the second discharge valve control unit may execute valve control in accordance with a value estimated by the pressure estimation unit.

Advantageous Effects of Invention

Therefore, according to the technology of the present disclosure, with the above configuration, it is possible to suitably control the discharge of the working fluid from the pressure chamber in the cylinder of the clutch actuator which is for switching between disengagement and engagement of the clutch device.

DESCRIPTION OF EMBODIMENTS

Hereinafter, an embodiment according to the present disclosure is described with reference to the drawings. The same components are denoted by the same reference numerals, and names and functions of these components are also the same. Therefore, detailed descriptions of the same components are not repeated.

FIG. 1is a schematic configuration diagram of a clutch system1including a clutch control device2according to an embodiment of the technology of the present disclosure.

The clutch system1includes a clutch device10, a clutch actuator20, the clutch control device2, and a stroke sensor18.

The clutch device10includes a flywheel12, a clutch disc13, a pressure plate14, a clutch cover15, a diaphragm spring16, and a release bearing17. The clutch disc13configures a clutch member, and the diaphragm spring16is a spring member, that is, an elastic, member.

The flywheel12is integrally rotatably connected to a crankshaft11to which a driving force of an engine (not shown) is transmitted. The clutch cover15is fixed to an outer peripheral edge of the flywheel12on a side opposite to the crankshaft11.

The clutch disc13includes a mounting portion13A which is arranged coaxially with the crankshaft11and is spline-fitted to an input shaft31of a transmission (not shown) so as to be axially movable and integrally rotatable, an annular disc main body portion13B fixed to an outer peripheral portion of the mounting portion13A, and friction plates13C fixed on both sides of an outer edge portion of the disc main body portion13B.

The pressure plate14is arranged on the clutch disc13on a side opposite to the flywheel12so as to be able to contact the friction plate13C. The diaphragm spring16is arranged such that an outer edge portion thereof is able to contact a surface of the pressure plate14on the side opposite to the flywheel12, and therefore, when the pressure plate14is pressed by the diaphragm spring16, the clutch disc13can be pressed against the flywheel12. When not being pressed by the diaphragm spring16, the pressure plate14is moved to the side opposite to the flywheel12by a spring (not shown), so that the clutch disc13is not pressed against the flywheel12.

The diaphragm spring16is a substantially conical spring member in a state with no load, and an intermediate portion of the diaphragm spring16between an inner edge portion and the outer edge portion is attached to the clutch cover15. The outer edge portion of the diaphragm spring16is arranged so as to come into contact with the pressure plate14on the side opposite to the flywheel12, and the inner edge portion of the diaphragm spring16is arranged so as to come into contact with a surface of the release bearing17on a flywheel17side.

In the present embodiment, when the release bearing17does not press the inner edge portion of the diaphragm spring16toward the flywheel12side, the outer edge portion of the diaphragm spring16presses the pressure plate14toward the flywheel12, so that the clutch disc13is pressed against the flywheel12, that is, the clutch device10is brought into an engagement state. In short, the diaphragm spring16is configured to act by exerting an urging force on the clutch member13. On the other hand, when the release bearing17presses the inner edge portion of the diaphragm spring16toward the diaphragm spring12side, the outer edge portion of the diaphragm spring16moves toward the side opposite to the flywheel12, and the outer edge portion of the diaphragm spring16does not press the pressure plate14, so that the clutch disc13is not pressed against the flywheel12, that is, the clutch device10is brought into a disengagement state. In short, in this way, the urging force applied from the diaphragm spring16to the clutch disc13serving as the clutch member is eliminated.

The release bearing17is configured such that a flywheel12side of an inner ring contacts the inner edge portion of the diaphragm spring16, and a side opposite to the flywheel12of an outer ring is connected to a piston22of the clutch actuator20described later, so that the diaphragm spring16and the piston22are rotatable relative to each other, and the release bearing17is movable in an axial direction of the input shaft31as the piston22moves in the axial direction.

The clutch actuator20has a cylinder21(as a cylinder member) arranged so as to be relatively rotatable around the input shaft31, and a piston22(as a piston member) provided inside the cylinder21so as to be movable in the axial direction. A pressure chamber23is formed by a surface of the piston22on the side opposite to the flywheel12and an inner wall of the cylinder21, and an open chamber24is formed by an outer peripheral surface of the piston22, a surface of the piston22on the flywheel12side, and the inner wall of the cylinder21.

The cylinder21is provided with supply pipes25A and25B for supplying air (an example of a working fluid) into the pressure chamber23and discharge pipes26A and26B for discharging the air from the pressure chamber23. Here, since air is used as the working fluid, the supply pipes25A and25B may be referred to as an air supply pipe, and the discharge pipes26A and26B may be referred to as an air discharge pipe. Further, the cylinder21is formed with an opening hole21A for communicating the open chamber24with the outside (for example, the outside under atmospheric pressure).

According to the clutch actuator20, by supplying air into the pressure chamber23, the piston22can be moved toward the flywheel12side, acid the clutch device10can be brought into the disengagement state. On the other hand, by discharging air from the pressure chamber23, the piston22can be moved toward the side opposite to the flywheel12by an elastic force of the diaphragm spring16, and the clutch device10can be brought into the engagement state.

The clutch control device2includes a first supply valve41A and a second supply valve41B arranged in parallel between a supply side for supplying air and the supply pipes25A,25B, a first discharge valve42A and a second discharge valve42B arranged in parallel between a discharge side for discharging air and the discharge pipes26A,26B, and a control device including a functional unit configured to control these valves41A,41B,42A, and42B separately. The control device corresponds to an electronic control unit (ECU)50. That is, the ECU50includes a first supply valve control unit50A configured to control operation of the first supply valve41A, a second supply valve control unit50B configured to control operation of the second supply valve41B, a first discharge valve control unit50C configured to control operation of the first discharge valve42A, and a second discharge valve control unit50D configured to control operation of the second discharge valve42B. Further, the ECU50includes an operation determination unit50E configured to make an operation determination of the clutch device10. The operation determination of the clutch device10made by the operation determination unit50E includes determination of whether it is necessary to perform an engagement process of the clutch device10, that is, a clutch engagement process, determination of whether to end the clutch engagement process, determination of whether it is necessary to perform an disengagement process of the clutch device10, that is, a clutch disengagement process, and determination of whether to end the clutch disengagement process. These functional units50A,50B,50C,50D,50E are associated with each other and electrically connected. Although not shown, compressed air having a predetermined pressure or higher is stored by a pump drive in the tank at a position different from the supply pipes25A,25B side of the supply valves41A,41B inFIG. 1.

The ECU50includes a known arithmetic device (for example, a central processing unit (CPU)), a storage device (for example, read only memory (ROM), random access memory (RAM)), an input/output port and the like, and has a so-called computer configuration. Here, the ECU50is provided with a functional unit as a control device of the clutch system1as described above. Although the ECU50also includes various functional units for the control of the engine, the control of the transmission, and the like, the ECU50may not include such functional units, and a description thereof is omitted below.

As shown inFIGS. 1 and 2, the stroke sensor18is connected to the ECU50, and the output thereof is input to the ECU50. The stroke sensor18is provided to detect a movement amount of the piston22of the clutch actuator20from a predetermined reference position, that is, a stroke value. Based on the output of the stroke sensor18, the ECU50can acquire the stroke value of the piston22. Further, the ECU50is configured to receive output of various sensors, for example, a vehicle speed sensor52for detecting a vehicle speed, and an accelerator opening degree sensor54for detecting an amount of depression of an accelerator pedal operated by the driver, that is, an accelerator opening degree (seeFIG. 2). The output of these sensors may be received directly or indirectly. Therefore, the ECU50can acquire the vehicle speed based on the output of the vehicle speed sensor52, and can acquire the accelerator opening degree based on the output of the accelerator opening degree sensor54. Although not shown, the ECU50is also configured to receive output of an engine rotation speed sensor or the like for detecting an engine rotation speed, but the illustration thereof is omitted.

Under the control of the ECU50, each of the supply valves41A and41B can be switched between a state in which the supply side (air supply side inFIG. 1) and the pressure chamber23are communicated with each other to supply air (supply state), and a state in which the supply side and the pressure chamber23are shut off to stop the air supply (supply stopped state). Further, under the control of the ECU50, each of the discharge valves42A and42B can be switched between a state in which the discharge side (air discharge side inFIG. 1) and the pressure chamber23are communicated with each other to discharge air (discharge state), and a state in which the discharge side and the pressure chamber23are shut off to stop the air discharge (discharge stopped state). Here, each of these valves41A,41B,42A, and42B is controlled by so-called duty control by the ECU50.

Next, control of the clutch device10by the clutch control device2in the clutch system1according to the present embodiment will be described.

FIG. 3is a flowchart of the clutch disengagement process according to the present embodiment. The clutch disengagement process is a process performed when the clutch device10is in the engagement state.

The calculation and control according to a routine of the clutch disengagement process ofFIG. 3is started, for example, when the power of the vehicle is turned on (a key switch of an ignition switch is turned on).

A clutch operation determination unit50E serving as the operation determination unit determines whether it is necessary to start the clutch disengagement process in order to perform gear shift by the transmission, based on a vehicle speed acquired based on the output from the vehicle speed sensor52, and an accelerator opening degree acquired based on the output from the accelerator opening degree sensor54, and the like (step S301). When the determination result is that (the start of) the clutch disengagement process (one of disengagement and engagement switching process of the clutch device10) is necessary (YES in step S301), the process proceeds to step S303. On the other hand, when the determination result is that it is not necessary to start the clutch disengagement process (NO in step S301), step S301is executed again.

When receiving from the clutch operation determination unit50E the output of the determination result that the clutch disengagement process is necessary, the first supply valve control unit50A and the second supply valve control unit50B execute opening control of the corresponding first supply valve41A and second supply valve41B respectively so as to perform the clutch disengagement process (step S303). At this time, both the first supply valve41A and the second supply valve41B may be subjected to the opening control at the same time, or only one of them may be subjected to the opening control, or any one of them may be subjected to the opening control and then the other is subjected to the opening control.

Then, the clutch operation determination unit50E determines whether to end the clutch disengagement process, that is, determines whether the stroke value acquired based on the output from the stroke sensor18reaches a stroke value in a clutch disengagement state (first predetermined value) (step S305). Then, if the stroke reaches the stroke value in the clutch disengagement state (YES in step S305), the clutch operation determination unit50E outputs a signal to stop the clutch operation to the first supply valve control unit50A and the second supply valve control unit50B. As a result, closing control of closing both the first supply valve41A and the second supply valve41B is executed (step S307).

FIG. 4is a flowchart of the clutch engagement process according to the present embodiment. The clutch engagement process is a process performed when the clutch device10is in the disengagement state.

The calculation and control according to a routine of the clutch engagement process ofFIG. 4is started, for example, when the power of the vehicle is turned on (a key switch of an ignition switch is turned on).

The clutch operation determination unit50E determines whether it is necessary to start the clutch engagement process after the gear shift by the transmission is completed (step S401). When the determination result is that (the start of) the clutch engagement process (one of the disengagement and engagement switching process of the clutch device10) is necessary (YES in step S401), the process proceeds to step S403. When the determination result is that it is not necessary to start the clutch engagement process (NO in step S401), the determination step in step S401is repeatedly executed.

When receiving from the clutch operation determination unit50E the output of the determination result that the clutch engagement process is necessary, the first discharge valve control unit50C performs opening control on the first discharge valve42A (step S403). At this time, the second discharge valve50D does not receive an output corresponding to the opening control of the second discharge valve42B from the clutch operation determination unit50E.

Then, the clutch operation determination unit50E determines whether the pressure in the pressure chamber23is lower than a predetermined pressure lower than a pressure of the pressure chamber23when the first discharge valve42A is opened (step S405). Specifically, as the determination, it is determined whether the stroke acquired based on the output from the stroke sensor18is less than a predetermined value, which is in a state between the clutch disengagement state and the clutch engagement state. This determination determines whether the acquired stroke value reaches a stroke value (second predetermined value S2) between a stroke value in the clutch disengagement state (first predetermined value S1) and a stroke value in the clutch engagement state (third predetermined value S3). Then, if the stroke is less than the predetermined value (YES in step S405), the clutch operation determination unit50E outputs a signal for executing a second stage of the clutch engagement operation to the second discharge valve control unit50D. As a result, the second discharge valve42B is subjected to the opening control in a state where the first discharge valve42A is already opened (step S407). The predetermined pressure in step S405and the predetermined value corresponding thereto are set in advance based on experiments and the like as a value at which the dischargeability of the working fluid from the pressure chamber23drops equal to or below a predetermined level, that is, a value at which the clutch responsiveness falls equal to or below a predetermined response level.

Then, the clutch operation determination unit50E determines whether to end the clutch engagement process, that is, determines whether the stroke value acquired based on the output from the stroke sensor18reaches the stroke value in the clutch engagement state (third predetermined value S3) (step S409). Then, if the stroke value reaches the stroke value in the clutch engagement state (YES in step S409), the clutch operation determination unit50E outputs a signal to stop the clutch operation to the first discharge valve control unit50C and the second discharge valve control unit50D. As a result, closing control of closing both the first discharge valve42A and the second discharge valve42B is executed (step S411).

The clutch engagement process is further described with reference toFIG. 5.FIG. 5shows an example of changes in the stroke with the horizontal axis representing time and the vertical axis representing the stroke of the piston22. InFIG. 5, a solid line (line L1) shows an example of change in target value in terms of control, and a dashed line (line L2) shows an example of changes in the stroke of the piston22by the clutch engagement process control. “S1” on the vertical axis ofFIG. 5corresponds to the stroke value in the clutch disengagement state, “S3” corresponds to the stroke in the clutch engagement state, and “S2” corresponds to the predetermined value in step S405.

When the clutch engagement process is started at time t1(YES in step S401ofFIG. 4), the first discharge valve42A is subjected to the opening control (step S403). At this time, only the first discharge valve42A is opened, but since the pressure of air, which is the working fluid in the pressure chamber23, is high, the working fluid can be quickly discharged from the pressure chamber23due to the pressure difference inside and outside the pressure chamber, and thus the stroke of the piston22can be changed rapidly. As a result, the stroke value detected by the piston22can be close to the target value.

However, since the pressure of the working fluid in the pressure chamber23becomes lower than the predetermined pressure from a certain time, the discharge of the working fluid via the first discharge valve42A starts to be delayed. As a result, the difference between the target value in terms of control and the stroke detected by the piston22begins to increase.

Therefore, a predetermined value as a stroke value corresponding to such a predetermined pressure is obtained in advance by experiments or the like, and when the detected stroke value becomes less than the predetermined value (YES in step S405), the second discharge valve42B is subjected to the opening control (step S407). As a result, both the first discharge valve42A and the second discharge valve42B are opened. Therefore, even if the pressure of the working fluid in the pressure chamber23is low, the working fluid can be suitably discharged from the pressure chamber23. Therefore, it is possible to prevent the operation delay in the clutch engagement process.

In the above embodiment, the stroke value of the piston22is detected, and the first discharge valve and the second discharge valve are controlled based an the stroke value. This is because the stroke of the piston has a correlation with the internal pressure of the working fluid in the pressure chamber23. Therefore, instead of the stroke sensor18, a pressure sensor for detecting the internal pressure of the pressure chamber23may be provided, and the first discharge valve and the second discharge valve may be controlled based on the internal pressure based on the output of the pressure sensor. Alternatively, the ECU50may estimate the internal pressure of the pressure chamber based on the acquired stroke value. In this case, the ECU50may store data or a relational expression indicating the relation between the stroke value and the internal pressure of the pressure chamber, which is determined in advance based on experiments or the like. As a result, the functional unit corresponding to a pressure estimation unit of the ECU50can estimate the pressure of the pressure chamber with the acquired stroke value for controlling of the various valves, for example.

Further, in the above embodiment, two discharge valves are provided, but three or more discharge valves may be provided. Similarly, three or more supply valves may be provided. However, at least one valve may be provided as the supply valve. That is, the ECU50may include a supply valve control unit configured to control operation of at least one supply valve.

The present disclosure is not limited to the above-described embodiment, and can be appropriately modified and implemented without departing from the scope of the present disclosure.

For example, in the above embodiment, the clutch system1is configured such that the clutch device10is brought into the disengagement state by supplying the working fluid to the pressure chamber23of the cylinder21of the clutch actuator20, and the clutch device10is brought into the engagement state by discharging the working fluid. However, the technology of the present disclosure is not limited to this, and the clutch system may also be configured such that the clutch device is brought into the engagement state by supplying the working fluid to the pressure chamber of the cylinder of the clutch actuator, and the clutch device is brought into the disengagement state by discharging the working fluid from the pressure chamber. That is, the diaphragm spring16may be provided so as to generate an urging force in a direction to bring the clutch member into the engagement state as in the above embodiment, or conversely, may be provided so as to generate an urging force in a direction to bring the clutch member into the disengagement state.

Further, in the above embodiment, although detailed description of the valve control is omitted, feedforward control or feedback control may be executed as the valve control. For example, the opening degree of the valve in an open state may be finely adjusted and controlled so that the stroke value detected based on the of the stroke sensor18follows the target value. Further, PID control may be performed as feedback control.

Further, in the above embodiment, the example in which air is used as the working fluid is shown, but the technology of the present disclosure is not limited to this, and hydraulic oil may be used as the working fluid.

The present application is based on Japanese Patent Application (No. 2018-050678) filed on Mar. 19, 2018, contents of which are incorporated herein as reference.

INDUSTRIAL APPLICABILITY

According to the present disclosure, it is possible: to suitably control the discharge of a working fluid from a pressure chamber in a cylinder of a clutch actuator which is for switching between disengagement and engagement of a clutch device.

REFERENCE SIGNS LIST