Clutch control device

Abstract

This clutch control device (40A) is provided with a clutch device (26), a clutch actuator (50), and a control unit (40). The control unit (40) performs clutch automatic disconnection control for disconnecting the clutch device (26) at the time of shifting and at the time of vehicle speed reduction and also makes the clutch disengagement speed (L12VB) of the clutch automatic disengagement control at the time of vehicle speed reduction slower than the clutch disengagement speed (L12VA) of the clutch automatic disengagement control at the time of shifting.

Description

Clutch control device

[0001] The present invention relates to a clutch control device.

[0002] Conventionally, there has been known a clutch control device that automatically performs an electrical control to connect and disconnect a clutch device (see, for example, Patent Documents 1 and 2). For example, Patent Document 1 discloses that when a vehicle is transitioning to a stop, the clutch is automatically disconnected to prevent the engine from stalling.

[0003] In a case where the clutch lever operated by the driver is mechanically connected to the clutch actuator, as in Patent Document 2, when the clutch is automatically disengaged by the clutch actuator, the movement of the clutch actuator is also transmitted to the clutch lever. While clutch disengagement control during gear shifting is within the driver's expectations, clutch disengagement control during a reduction in vehicle speed can cause the clutch lever to behave unexpectedly, which may cause the driver to feel uncomfortable.

[0004] Japanese Unexamined Patent Publication No. 9-324827 Japanese Unexamined Patent Publication No. 2005-106246

[0005] Therefore, an object of the present invention is to suppress the discomfort felt when clutch disengagement control is performed when vehicle speed decreases in a clutch control device that allows manual and automatic clutch operation. The present invention aims to improve operability in order to solve the above-mentioned problems. This will ultimately further improve traffic safety and contribute to the development of a sustainable transportation system.

[0006] A first aspect of the present invention is a clutch control device (40A) including a clutch device (26) that connects and disconnects power transmission between a prime mover (13) of a vehicle (1) and an output target (21), a clutch actuator (50) that actuates the clutch device (26), and a control unit (40) that controls the drive of the clutch actuator (50), wherein the control unit (40) performs automatic clutch disengagement control to disengage the clutch device (26) when shifting gears and when vehicle speed is reduced, and sets a clutch disengagement speed (L12VB) of the automatic clutch disengagement control when vehicle speed is reduced to be slower than a clutch disengagement speed (L12VA) of the automatic clutch disengagement control when shifting gears. According to this configuration, by setting the clutch disengagement speed of the automatic clutch disengagement control when vehicle speed is reduced to be slower than the clutch disengagement speed of the automatic clutch disengagement control when shifting gears, unexpected movement of a clutch operator that the driver touches due to sudden clutch disengagement control is suppressed, and discomfort caused by the automatic clutch disengagement control when vehicle speed is reduced can be suppressed.

[0007] In a second aspect of the present invention, in the first aspect, the automatic clutch disengagement control when the vehicle speed decreases is performed at either a mitigation clutch disengagement speed that is set when the rate of decrease in vehicle speed or engine speed is less than a specified threshold, or an engine stall prevention clutch disengagement speed that is set when the rate of decrease in vehicle speed or engine speed is equal to or greater than the threshold, and the mitigation clutch disengagement speed is set slower than the engine stall prevention clutch disengagement speed. With this configuration, by setting different speeds for the mitigation clutch disengagement speed and the engine stall prevention clutch disengagement speed and switching between them depending on the rate of decrease in vehicle speed or engine speed, it is possible to achieve both an improved lever feeling and the prevention of engine stalls.

[0008] In a third aspect of the present invention, in the second aspect, the control unit (40) has an automatic control mode (M1) in which the clutch device (26) is automatically actuated by driving the clutch actuator (50), and a manual control intervention mode (M3) in which the clutch device (26) is manually actuated by inputting an operation to a clutch operator (4 b) operated by a driver, and if a predetermined condition for returning to the automatic control mode (M1) is satisfied during control in the manual control intervention mode (M3), the control unit (40) automatically returns to the automatic control mode (M1). According to this configuration, if a predetermined condition for returning to the automatic control mode is satisfied during control in the manual control intervention mode, the automatic control mode is automatically restored, thereby preventing the driver from mistaking the control mode and performing a gear shift operation (especially, operating in gear without operating the clutch despite being in the manual control intervention mode), thereby avoiding engine stalls due to forgetting to disengage the clutch, and improving operability.

[0009] In a fourth aspect of the present invention, in the third aspect, when the vehicle speed or engine revolutions falls to a prescribed rate change determination threshold (W1) in the manual control intervention mode (M3), and the rate of decline in the vehicle speed or engine revolutions is equal to or greater than a prescribed engine stall avoidance determination threshold (W2), automatic clutch disengagement control is performed at the engine stall avoidance clutch disengagement speed. According to this configuration, when the vehicle speed or engine revolutions is less than the rate change determination threshold and the rate of decline in the vehicle speed or engine revolutions is equal to or greater than the engine stall avoidance determination threshold, automatic clutch disengagement is performed at a relatively fast engine stall avoidance clutch disengagement speed, thereby making it possible to prevent engine stalls due to delays in automatic clutch disengagement.

[0010] In a fifth aspect of the present invention, in the fourth aspect, the clutch automatic disengagement control during a decrease in vehicle speed is performed when the vehicle speed becomes equal to or lower than threshold values ​​(V1, V2), and a first threshold value (V1) for determining the execution of the clutch automatic disengagement control in the manual control intervention mode (M3) is set lower than a second threshold value (V2) for determining the execution of the clutch automatic disengagement control in the automatic control mode (M1). According to this configuration, by setting the clutch disengagement execution threshold value in the manual control intervention mode lower than the clutch disengagement execution threshold value in the automatic control mode, it is possible to respect the driver's intentions as much as possible during the manual control intervention mode and to facilitate an improvement in the lever feeling during the automatic control mode.

[0011] In a sixth aspect of the present invention, in the first or second aspect, the clutch automatic disengagement control when the vehicle speed decreases is initiated when a specified parameter reaches a threshold value (V1, V2), and the threshold value (V1, V2) varies depending on the gear position of the transmission (21) of the vehicle (1). According to this configuration, the start timing of the clutch automatic disengagement control when the vehicle speed decreases varies depending on the gear position of the transmission, making it possible to set the clutch automatic disengagement control to start earlier, for example, the higher the gear position, thereby increasing the reliability of avoiding engine stalls.

[0012] In a seventh aspect of the present invention, in the sixth aspect, when the gear of the transmission (21) is on the high side relative to the vehicle speed, a notification is given to the driver to prompt the driver to perform a gear change. With this configuration, by giving a notification when the gear of the transmission (21) is high relative to the vehicle speed, it is possible to increase the possibility of a downshift and, in particular, to increase the certainty that the gear will be returned to a low gear equivalent by the time the vehicle comes to a stop. This reduces the possibility of starting in a high gear and suppresses deterioration of the clutch device.

[0013] According to the clutch control device of the present invention, in a clutch control device that allows manual and automatic operation of the clutch, it is possible to suppress the feeling of discomfort caused by clutch disengagement control when the vehicle speed decreases.

[0014] 1. A right side view of a motorcycle according to the present embodiment. 2. A cross-sectional view of a transmission and a change mechanism of the motorcycle. 3. A block diagram of a gear change system for the motorcycle. 4. An explanatory diagram showing transitions in clutch control modes of the motorcycle, the cross-sectional view being taken along the axial direction of the clutch actuator. 5. A perspective view of a release shaft that actuates a clutch device. 6. A cross-sectional view taken along line VII-VII of FIG. 5. 7. A cross-sectional view corresponding to FIG. 7 showing operation of the release shaft in a half-clutch region, illustrating driving by the clutch actuator. 8. A cross-sectional view corresponding to FIG. 7 showing operation of the release shaft in a half-clutch region, illustrating manual intervention. 9. A cross-sectional view corresponding to FIG. 7 showing operation of the release shaft at a standby position, illustrating driving by the clutch actuator. 10. A cross-sectional view corresponding to FIG. 7 showing operation of the release shaft at a standby position, illustrating manual intervention. 11. A time chart showing time changes of parameters when performing automatic clutch disengagement control in a comparative example. 12. A time chart showing time changes of parameters when performing automatic clutch disengagement control in an embodiment. 13. A time chart corresponding to FIG. 10B in a modified example of the embodiment. 14. A time chart corresponding to FIG. 10B in another modified example of the embodiment. It is an explanatory diagram showing a basic control state of the clutch control device. It is a flowchart showing a process when setting a clutch disengagement rate limit. It is a flowchart showing a process when determining whether to return to an auto mode. It is a flowchart showing a process when performing engine stall avoidance determination control.

[0015] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following description, directions such as front, rear, left, and right are the same as directions in the vehicle described below unless otherwise specified. In addition, an arrow FR indicating the front of the vehicle, an arrow LH indicating the left side of the vehicle, and an arrow UP indicating the top of the vehicle are shown in appropriate locations in the drawings used in the following description. The term "middle" used in this embodiment refers not only to the center between both ends of an object, but also to the range inside the both ends of the object.

[0016] <Overall Vehicle> As shown in Figure 1, this embodiment is applied to a motorcycle 1, which is an example of a saddle-ride type vehicle. A front wheel 2 of the motorcycle 1 is supported at the lower ends of a pair of left and right front forks 3. Upper portions of the left and right front forks 3 are supported via a steering stem 4 on a head pipe 6 at the front end of a body frame 5. A bar-type steering handlebar 4a is attached to the top bridge of the steering stem 4.

[0017] The body frame 5 includes a head pipe 6, a main frame 7 extending downward and rearward from the head pipe 6 at the center in the vehicle width direction (left and right direction), a pivot frame 8 provided below the rear end of the main frame 7, and a seat frame 9 connected to the rear of the main frame 7 and the pivot frame 8. A front end of a swing arm 11 is pivotally supported on the pivot frame 8 so that it can swing. A rear wheel 12 of the motorcycle 1 is supported on the rear end of the swing arm 11.

[0018] A fuel tank 18 is supported above the left and right main frames 7. A front seat 19 and a rear seat 19a are supported behind the fuel tank 18 and above the seat frames 9. Knee grip portions 18a that are recessed inward in the vehicle width direction are formed on both the left and right sides of the rear of the fuel tank 18. The left and right knee grip portions 18a are formed to fit in the following areas: the inside of the areas around the left and right knees of a driver seated on the front seat 19. Steps 18b are supported on both the left and right sides below the front seat 19. The driver places their ankles and feet on the steps 18b.

[0019] A power unit PU including a prime mover of the motorcycle 1 is suspended below the main frame 7. The power unit PU integrally includes an engine (internal combustion engine, prime mover) 13 located in front of it and a transmission (output target) 21 located in the rear. The engine 13 is, for example, a multiple-cylinder engine with the rotation axis of a crankshaft 14 aligned in the left-right direction (vehicle width direction).

[0020] The engine 13 has a cylinder 16 that stands upright above the front part of the crankcase 15. The rear part of the crankcase 15 forms a transmission case 17 that houses a transmission 21. A right cover 17a is attached to the right side of the crankcase 15 and spans the right side of the transmission case 17. The right cover 17a also serves as a clutch cover that covers the clutch device 26. The power unit PU is connected to the rear wheel 12 via, for example, a chain-type transmission mechanism (not shown).

[0021] <Transmission> Referring also to Figure 2, the transmission 21 is a stepped transmission. The transmission 21 has a main shaft 22, a counter shaft 23, and a group of speed change gears 24 that straddles both shafts 22, 23. The counter shaft 23 constitutes the output shaft of the transmission 21 and therefore the power unit PU. The left end of the counter shaft 23 protrudes to the left of the rear of the transmission case 17 and is connected to the rear wheel 12 via the chain transmission mechanism.

[0022] The main shaft 22 and countershaft 23 of the transmission 21 are disposed rearward of the crankshaft 14. A clutch device 26 is disposed coaxially on the right end of the main shaft 22. The clutch device 26 connects and disconnects the power transmission between the crankshaft 14 of the engine 13 and the main shaft 22 of the transmission 21. The clutch device 26 is connected and disconnected by at least one of the operation of a clutch operator (clutch lever 4b) by the rider and the operation of a clutch actuator 50, which will be described in detail later.

[0023] The clutch device 26 is, for example, a wet multi-plate clutch, a so-called normally closed clutch. The rotational power of the crankshaft 14 is transmitted to the main shaft 22 via the clutch device 26, and then transmitted from the main shaft 22 to the countershaft 23 via any gear pair of the transmission gear set 24. A drive sprocket 27 of the chain transmission mechanism is attached to the left end of the countershaft 23, which protrudes to the left of the rear of the crankcase 15.

[0024] A change mechanism 25 that switches between gear pairs in the transmission gear group 24 is housed near the transmission 21 within the transmission case 17. The change mechanism 25 has a hollow cylindrical shift drum 32 that is parallel to both shafts 22, 23. By rotation of this shift drum 32, the change mechanism 25 actuates a plurality of shift forks 32a. This actuation is performed according to the pattern of lead grooves formed on the outer periphery of the shift drum 32. By this actuation, the change mechanism 25 switches between gear pairs used for power transmission between both shafts 22, 23 in the transmission gear group 24.

[0025] Here, in the motorcycle 1, only the driver operates the transmission 21 (operating a shift pedal (not shown) with his foot), and the clutch device 26 is automatically engaged and disengaged through electrical control in response to the operation of the shift pedal. In other words, the motorcycle 1 employs a so-called semi-automatic transmission system (automatic clutch-type transmission system).

[0026] <Transmission System> As shown in FIG. 3 , the transmission system 30 includes a clutch actuator 50, a control unit 40, various sensors 41-46, and various devices 47, 48, and 50. The control unit 40 controls the operation of an ignition device 47 and a fuel injection device 48, as well as the operation of the clutch actuator 50. This control is based on detection information from an acceleration sensor 41, a gear position sensor 42, and a shift load sensor 43 (e.g., a torque sensor), as well as various vehicle state detection information from a throttle opening sensor 44, a vehicle speed sensor 45, and an engine rotation speed sensor 46. The acceleration sensor 41 detects the behavior of the vehicle body. The gear position sensor 42 detects the gear position from the rotation angle of the shift drum 32. The shift load sensor 43 detects the operating torque input to the shift spindle 31 (see FIG. 2 ) of the change mechanism 25. The throttle opening sensor 44 detects the throttle opening. The vehicle speed sensor 45 detects the vehicle speed. The engine speed sensor 46 detects the engine speed.

[0027] The control unit 40 includes a clutch control unit 40C and an engine control unit 40E, which are independent of each other. The clutch control unit 40C mainly controls the drive of the clutch actuator 50. The engine control unit 40E mainly controls the drive of the engine 13. The clutch control unit 40C and the engine control unit 40E are configured, for example, as separate ECUs (Electronic Control Units). The clutch control unit 40C and the engine control unit 40E may also be configured within an integrated ECU, as long as they perform independent control of each other.

[0028] 2 and 5 , clutch actuator 50 controls the operating torque applied to release shaft 53 to engage and disengage clutch device 26. Clutch actuator 50 includes an electric motor 52 (electric motor, hereinafter simply referred to as motor 52) as a drive source, and a speed reduction mechanism (reduction gear mechanism, transmission mechanism) 51 that transmits the drive force of motor 52 to release shaft 53. Speed ​​reduction mechanism 51 includes a first reduction shaft 57, a second reduction shaft 58, and a third reduction shaft 56. For example, third reduction shaft 56 is provided with a rotation angle sensor (rotational motion sensor) 56d that detects, for example, the rotation angle of third reduction shaft 56.

[0029] Referring to FIG. 3, the clutch control unit 40C calculates the following current values ​​based on a preset calculation program. These current values ​​are values ​​of current supplied to the motor 52 to connect and disconnect the clutch device 26. The current supplied to the motor 52 is determined based on a correlation with the torque output by the motor 52. The target torque of the motor 52 is proportional to the operating torque (driven clutch lever torque, described later) applied to the release shaft 53. The current value supplied to the motor 52 is detected by a current sensor 40b included in the clutch control unit 40C. The operation of the clutch actuator 50 is controlled in accordance with changes in this detected value. The clutch actuator 50 will be described in detail later.

[0030] <Clutch Device> As shown in Figure 2, the clutch device 26 of this embodiment is a multi-plate clutch in which a plurality of clutch plates 35 are stacked in the axial direction, and is a wet clutch disposed in an oil chamber inside the right cover 17a. The clutch device 26 includes a clutch outer 33, a clutch center 34, and a plurality of clutch plates 35. The clutch outer 33 is driven by constant rotational power transmitted from the crankshaft 14. The clutch center 34 is disposed within the clutch outer 33 and supported by the main shaft 22 so as to be integrally rotatable. The plurality of clutch plates 35 are stacked between the clutch outer 33 and the clutch center 34, frictionally engaging them.

[0031] A pressure plate 36 having approximately the same diameter as the clutch plates 35 is disposed to the right (outside in the vehicle width direction) of the stacked clutch plates 35. The pressure plate 36 is biased leftward by the elastic load of a clutch spring 37, causing the stacked clutch plates 35 to press together (frictionally engage). This places the clutch device 26 in a connected state that allows power transmission. The clutch device 26 is a normally closed clutch that is normally connected when there is no external input.

[0032] The pressure contact (frictional engagement) is released by actuation of a release mechanism 38 inside the right cover 17a. The actuation of the release mechanism 38 is effected by at least one of the operation of the clutch lever 4b by the occupant and the application of torque by the clutch actuator 50.

[0033] <Release Mechanism> As shown in FIG. 2, the release mechanism 38 includes a lifter shaft 39 and a release shaft 53. The lifter shaft 39 is supported within the right side of the main shaft 22 so as to be reciprocable in the axial direction. The release shaft 53 is disposed perpendicular to the axial direction of the lifter shaft 39 and is supported on the outer side of the right cover 17a so as to be rotatable about its axis. Line C4 in the figure indicates the central axis of the release shaft 53, which extends vertically. When viewed in the axial direction of the main shaft 22 (as viewed from the side of the vehicle), the release shaft 53 is tilted rearward in the axial direction so that the upper end of the release shaft 53 is positioned more rearward than the vertical direction (see FIG. 1). The upper portion of the release shaft 53 protrudes outside the right cover 17a, and a driven clutch lever 54 is attached to the upper portion of the release shaft 53 so as to be rotatable integrally therewith. The driven clutch lever 54 is connected to the clutch lever 4b via an operating cable 54c.

[0034] An eccentric cam portion 38a is provided on the lower portion of the release shaft 53, located inside the right cover 17a. The eccentric cam portion 38a engages with the right end portion of the lifter shaft 39. When the release shaft 53 rotates around its axis, the eccentric cam portion 38a acts to move the lifter shaft 39 to the right. The lifter shaft 39 is configured to reciprocate integrally with the pressure plate 36 of the clutch device 26. Therefore, when the lifter shaft 39 moves to the right, the pressure plate 36 moves (lifts) to the right against the biasing force of the clutch spring 37. This releases the frictional engagement between the stacked clutch plates 35. This places the normally closed clutch device 26 in a disconnected state, preventing power transmission.

[0035] It should be noted that release mechanism 38 is not limited to an eccentric cam mechanism and may be one that includes a rack and pinion, a feed screw, etc. The mechanism that connects clutch lever 4b and driven clutch lever 54 is not limited to operation cable 54c and may be one that includes a rod, a link, etc. Also, a configuration may be adopted in which an oil passage is provided between clutch lever 4b and release shaft 53, and hydraulic pressure generated by a master cylinder on the clutch lever 4b side is transmitted to a slave cylinder on the release shaft 53 side, and operation of the slave cylinder rotates release shaft 53.

[0036] <Clutch Control Modes> As shown in Figure 4, the clutch control device 40A of this embodiment has three clutch control modes. The clutch control modes include an auto mode M1 for automatic control, a manual mode M2 ​​for manual operation, and a manual intervention mode M3 for temporary manual operation. The clutch control mode transitions between the three modes as appropriate in response to the operation of the clutch control mode selector switch 49 (see Figure 3) and the clutch lever 4b. The manual mode M2 ​​and the manual intervention mode M3 are collectively referred to as a manual system M2A.

[0037] Auto mode M1 is a mode in which a clutch capacity appropriate for the driving state is calculated in accordance with automatic start / gear change control, and the clutch device 26 is controlled. Manual mode M2 ​​is a mode in which a clutch capacity is calculated in accordance with a clutch operation instruction from the occupant, and the clutch device 26 is controlled. Manual intervention mode M3 is a temporary manual operation mode in which a clutch operation instruction from the occupant is received during auto mode M1, and the clutch capacity is calculated from the clutch operation instruction to control the clutch device 26. Note that manual intervention mode M3 may be set to return to auto mode M1 if, for example, the occupant stops operating the clutch lever 4b (completely released state) for a specified time.

[0038] For example, when the system is started, the clutch control device 40A starts control in the auto mode M1 with the clutch on (connected state). Also, when the engine 13 is stopped (when the system is off), the clutch control device 40A is set to return to the auto mode M1 with the clutch on. In a normally closed clutch device 26, when the clutch is on, power supply to the motor 52 of the clutch actuator 50 is not required. On the other hand, when the clutch device 26 is in the clutch off state (disconnected state), power supply to the motor 52 is maintained.

[0039] The auto mode M1 is basically a mode in which clutch control is performed automatically. In the auto mode M1, the motorcycle 1 can be driven without lever operation. In the auto mode M1, the clutch capacity is controlled based on the throttle opening, engine speed, vehicle speed, shift sensor output, and the like. This allows the motorcycle 1 to start without stalling (meaning engine stop or engine stall) by operating the throttle alone. The motorcycle 1 can also be changed gears by shifting alone. In addition, in the auto mode M1, the rider can switch to the manual intervention mode M3 by gripping the clutch lever 4b. This allows the clutch device 26 to be disengaged at will.

[0040] On the other hand, in manual mode M2, the clutch capacity can be controlled by the rider operating a lever (i.e., the clutch device 26 can be engaged or disengaged). Switching between auto mode M1 and manual mode M2 ​​is possible. This switching is performed, for example, by operating the clutch control mode changeover switch 49 (see FIG. 3) while the motorcycle 1 is stopped and the transmission 21 is in neutral. The clutch control device 40A may be provided with an indicator that shows that the clutch control mode is in the manual state when transitioning to the manual system M2A (manual mode M2 ​​or manual intervention mode M3).

[0041] The manual mode M2 ​​is basically a mode in which the clutch is controlled manually. In the manual mode M2, the clutch capacity can be controlled according to the operating angle of the clutch lever 4b (and thus the operating angle of the driven clutch lever 54). This allows the driver to control the engagement and disengagement of the clutch device 26 at will.

[0042] For example, a lever holder that holds the clutch lever 4b is provided with a clutch switch 4c that is turned on when the clutch lever 4b is gripped (clutch disengaged) and turned off when the clutch lever 4b is released (clutch engaged). The control unit 40 can detect whether the driver is operating the clutch by checking whether the clutch switch 4c is on or off.

[0043] In the automatic mode M1, the clutch actuator 50 automatically engages and disengages the clutch device 26. At this time, manual clutch operation of the clutch lever 4b can be performed to temporarily intervene manually in the automatic control of the clutch device 26 (manual intervention mode M3).

[0044] <Manual Clutch Operation> In the motorcycle 1 shown in Figure 1, a clutch lever 4b serving as a manual clutch operator is attached to the base end side (inner side in the vehicle width direction) of the left grip of the steering handlebar 4a. Referring also to Figure 2, the clutch lever 4b is connected via an operation cable 54c to a driven clutch lever 54 attached to a release shaft 53 of the clutch device 26. The driven clutch lever 54 is attached to an upper end of the release shaft 53 that protrudes above the right cover 17a so as to be rotatable together with the release shaft 53.

[0045] Furthermore, for example, a handle switch (not shown) attached to the steering handle 4a is provided with the clutch control mode changeover switch 49. This allows the occupant to easily change the clutch control mode during normal driving.

[0046] <Clutch Actuator> As shown in Figure 1, a clutch actuator 50 is attached to the top of the right cover 17a on the right side of the crankcase 15. Referring also to Figure 5, the clutch actuator 50 includes a motor 52 and a speed reduction mechanism 51. The motor 52 is, for example, a DC motor, and is disposed, for example, with its axial direction parallel to that of a release shaft 53. The motor 52 is disposed so that its drive shaft 55 protrudes upward. The speed reduction mechanism 51 transmits the driving force of the motor 52 to the release shaft 53. Hereinafter, the axial direction common to the motor 52 and the release shaft 53 will be referred to as the "actuator axial direction."

[0047] In this embodiment, a single clutch actuator 50 is provided with multiple (two) motors 52. Hereinafter, the motor 52 located on the vehicle front side of the clutch actuator 50 will be referred to as the first motor 521, and the motor 52 located on the vehicle rear side and inward in the vehicle width direction relative to the first motor 521 will be referred to as the second motor 522. Lines C01 and C02 in the figure indicate the central axes (drive axes) of the motors 521 and 522, respectively. For convenience of explanation, both motors 521 and 522 may be collectively referred to as motors 52. Furthermore, both axes C01 and C02 may be collectively referred to as axis C0.

[0048] The reduction mechanism 51 reduces the speed of the rotational power output from the motor 52 and transmits the reduced power to the release shaft 53. The reduction mechanism 51 includes, for example, a gear train whose axial direction is parallel to that of the release shaft 53. The reduction mechanism 51 includes a drive gear 55a, a first reduction gear 57a, a first small-diameter gear 57b, a second reduction gear 58a, a second small-diameter gear 58b, a third reduction gear 56a, a third small-diameter gear 56b, a driven gear 63a, and a gear case (mechanism case) 59.

[0049] The drive gear 55a is integrally provided on the drive shaft 55 of each motor 521, 522. The first reduction gear 57a meshes with each drive gear 55a. The first small diameter gear 57b is provided coaxially with the first reduction gear 57a. The second reduction gear 58a meshes with the first small diameter gear 57b. The second small diameter gear 58b is provided coaxially with the second reduction gear 58a. The third reduction gear 56a meshes with the second small diameter gear 58b. The third small diameter gear 56b is provided coaxially with the third reduction gear 56a. The driven gear 63a meshes with the second small diameter gear 58b. A gear case 59 houses each gear.

[0050] The first reduction gear 57a and the first small-diameter gear 57b are supported by a first support shaft 57c so as to be rotatable together. The first reduction gear 57a, the first small-diameter gear 57b, and the first support shaft 57c constitute a first reduction shaft 57. The second reduction gear 58a and the second small-diameter gear 58b are supported by a second support shaft 58c so as to be rotatable together. The second reduction gear 58a, the second small-diameter gear 58b, and the second support shaft 58c constitute a second reduction shaft 58.

[0051] The third reduction gear 56a and the third small-diameter gear 56b are supported on a third support shaft 56c so as to be rotatable together. The third reduction gear 56a, the third small-diameter gear 56b, and the third support shaft 56c constitute the third reduction shaft 56. The third reduction gear 56a is a sector-shaped gear centered on the third support shaft 56c. In the drawing, line C1 indicates the central axis of the first reduction shaft 57, line C2 indicates the central axis of the second reduction shaft 58, and line C3 indicates the central axis of the third reduction shaft 56.

[0052] The driven gear 63a is provided to be rotatable integrally with the release shaft 53. The driven gear 63a is a sector gear centered on the release shaft 53. The gear on the downstream side in the reduction mechanism 51 has a small rotation angle. Therefore, the third reduction gear 56a and the driven gear 63a can be sector gears with small rotation angles.

[0053] As a result, it is possible to reduce the size of the reduction mechanism 51 and, in turn, the clutch actuator 50. That is, even when a large-diameter reduction gear is provided to increase the reduction ratio, by cutting out the area outside the meshing range of this reduction gear to form a sector shape, the following effects are achieved: In particular, it is possible to prevent the reduction mechanism 51 from protruding outward in the vehicle width direction, and it is also possible to reduce the weight of the reduction mechanism 51.

[0054] With this configuration, the motor 52 and the release shaft 53 can be constantly linked via the speed reducing mechanism 51. This forms a system in which the clutch actuator 50 directly connects and disconnects the clutch device 26.

[0055] A rotation angle sensor 56d is provided on the upper surface side of gear case 59. Rotation angle sensor 56d is arranged outside gear case 59 and is connected to one end of third reduction shaft 56 protruding outside the case to detect the rotation angle of the third reduction shaft 56. By detecting the rotation angle of third reduction shaft 56 close to release shaft 53, the detection accuracy of the rotation angle of release shaft 53, and therefore of the clutch capacity, is improved.

[0056] The driving force of motor 52 is decelerated as follows before being transmitted to release shaft 53. That is, the driving force of motor 52 is decelerated between drive gear 55a and first reduction gear 57a, between first small-diameter gear 57b and second reduction gear 58a, between second small-diameter gear 58b and third reduction gear 56a, and further between third small-diameter gear 56b and driven gear 63a.

[0057] <Arrangement of Clutch Actuator> As shown in Figure 1, the clutch actuator 50 is arranged vertically below the knee grip portion 18a on the right side of the fuel tank 18 in a side view of the vehicle. In the figure, line L1 represents the thigh of the driver's leg, line L2 represents the lower leg from the knee down, and line L3 represents the foot from the ankle down. In a side view of the vehicle, the driver's lower leg L2 extends diagonally rearward and downward from the knee grip portion 18a, and the foot L3 rests on the step 18b.

[0058] The clutch actuator 50 protrudes outward in the vehicle width direction beyond the knee grip portion 18a. The clutch actuator 50 is positioned to avoid the driver's lower leg L2 in front of it in a side view of the vehicle. This reduces interference of the clutch actuator 50 with the space for the driver's legs to be placed. Even when the driver stretches his or her legs and lands with his or her foot L3, the clutch actuator 50 is positioned to avoid the driver's lower leg L2 in a side view of the vehicle to be placed. This also reduces interference of the clutch actuator 50 with the space for the driver's legs to be placed.

[0059] 5 and 6 , the release shaft 53 is divided into multiple elements so that it can rotate in response to inputs from the clutch actuator 50 and inputs from the driver's operation, separately. The release shaft 53 includes an upper release shaft 61 that forms the upper part, a lower release shaft 62 that forms the lower part, and an intermediate release shaft 63. The intermediate release shaft 63 is disposed between the lower end of the upper release shaft 61 and the upper end of the lower release shaft 62.

[0060] The upper release shaft 61 has a cylindrical shape. The upper release shaft 61 is rotatably supported by the upper boss portion 59b of the gear case 59. The upper end of the upper release shaft 61 protrudes outside the gear case 59. The driven clutch lever 54 is supported at the upper end of the upper release shaft 61 so as to be rotatable integrally therewith. A return spring (not shown) is attached to the driven clutch lever 54. This return spring applies a biasing force to the driven clutch lever 54 in the direction opposite to the rotation (rotation in the clutch disengagement direction) caused by operation of the clutch lever 4b.

[0061] The lower release shaft 62 has a cylindrical shape. The lower part of the lower release shaft 62 is rotatably supported inside the right cover 17a. The lower part of the lower release shaft 62 faces the inside of the gear case 59. The eccentric cam portion 38a of the release mechanism 38 is formed at this lower part (see FIG. 2). A lower return spring (not shown) is attached to the lower end of the lower release shaft 62. This lower return spring applies a biasing force to the lower release shaft 62 in the direction opposite to the rotation in the clutch disengagement direction.

[0062] 7, a manual operation side cam 61b that extends in the axial direction and has a sector-shaped cross section is provided at the lower end of the upper release shaft 61. A clutch side cam 62b that extends in the axial direction and has a sector-shaped cross section is provided at the upper end of the lower release shaft 62. The clutch side cam 62b is provided in a range that avoids the manual operation side cam 61b in the circumferential direction.

[0063] The lower end portion (manual operation side cam 61b) of the upper release shaft 61 and the upper end portion (clutch side cam 62b) of the lower release shaft 62 overlap in the axial direction while avoiding each other in the circumferential direction, which allows one circumferential side surface 61b1 of the manual operation side cam 61b to press the other circumferential side surface 62b2 of the clutch side cam 62b, thereby rotating the lower release shaft 62 (see Figures 8B and 9B).

[0064] The other circumferential side surface 61b2 of the manual operation side cam 61b and the one circumferential side surface 62b1 of the clutch side cam 62b are spaced apart from each other in the circumferential direction, so that when an input is applied to the clutch side cam 62b from the clutch actuator 50, the lower release shaft 62 can be rotated independently of the upper release shaft 61 (see FIGS. 8A and 9A).

[0065] The intermediate release shaft 63 has, for example, a cylindrical shape. The intermediate release shaft 63 can be inserted through the engagement portion (upper and lower shaft engagement portion) between the lower end of the upper release shaft 61 and the upper end of the lower release shaft 62. A driven gear 63a is supported on the intermediate release shaft 63 so as to be rotatable integrally therewith. A control operation side cam 63b having a sector-shaped cross section and extending in the axial direction is provided on the intermediate release shaft 63.

[0066] The control operation side cam 63b of the intermediate release shaft 63 and the clutch side cam 62b of the lower release shaft 62 overlap in the axial direction while avoiding each other in the circumferential direction, which allows one circumferential side surface 63b1 of the control operation side cam 63b to press the other circumferential side surface 62b2 of the clutch side cam 62b, thereby rotating the lower release shaft 62.

[0067] The control operation side cam 63b is disposed so as to avoid, in the radial direction, the manual operation side cam 61b of the upper release shaft 61. This allows the lower release shaft 62 to rotate independently of the upper release shaft 61 when transmitting input from the clutch actuator 50 to the clutch side cam 62b. Furthermore, when manual operation is performed, the upper release shaft 61 can rotate independently of the control side intermediate release shaft 63.

[0068] The other circumferential side surface 63b2 of the control operation side cam 63b and the one circumferential side surface 62b1 of the clutch side cam 62b are spaced apart from each other in the circumferential direction, so that when an input is applied to the clutch side cam 62b from the manual operation side cam 63b, the lower release shaft 62 can rotate independently of the intermediate release shaft 63.

[0069] 5, clutch actuator 50 has an upper release shaft 61 and an intermediate release shaft 63 rotatably held by gear case 59. Clutch actuator 50 includes upper release shaft 61 and intermediate release shaft 63. Lower release shaft 62 is rotatably held by right cover 17a. The upper end of lower release shaft 62 protrudes outside the cover at an actuator mounting portion of right cover 17a and is inserted into gear case 59.

[0070] In this configuration, when the clutch actuator 50 is attached to the right cover 17a, a linear release shaft 53 is formed together with the lower release shaft 62 on the right cover 17a side. The release shaft 53 is formed by interconnecting the upper release shaft 61, the intermediate release shaft 63, and the lower release shaft 62.

[0071] The power unit PU of the embodiment can be configured as follows for a manual clutch power unit in which the clutch device 26 is engaged and disengaged by the driver rather than electrically controlled. That is, the power unit PU can be configured by replacing the right cover 17a and the release shaft 53 and retrofitting the clutch actuator 50. Therefore, the clutch actuator 50 can be attached to power units of different models. Therefore, the clutch actuator 50 can be shared among multiple models, making it easy to configure a semi-automatic transmission system (automatic clutch transmission system).

[0072] <Two-Motor Control> Referring to FIG. 5 , in this embodiment, two motors 521, 522 in the clutch actuator 50 may cooperate to drive the release shaft 53 (to engage and disengage the clutch device 26). In this case, the load shared by the two motors 521, 522 is halved, thereby enabling the size of each motor 521, 522 to be reduced. This increases the degree of freedom in the layout of the motor 52 compared to when a single large motor 52 is provided. Therefore, even when the clutch actuator 50 is disposed on the outer side of the power unit PU, it is easy to prevent the clutch actuator 50 from protruding outward in the vehicle width direction. This makes it possible to substantially reduce the size of the clutch control device 40A.

[0073] In the embodiment, in the clutch actuator 50, under normal circumstances (non-failure), one of the multiple (two) motors 52 may be used as the drive source for the release shaft 53, and the remaining one may be used for another purpose. For example, the remaining one motor 52 may refrain from operating as a fail-safe, or may be used as a current sensor.

[0074] <Basic Control State of Clutch Control Device> Figure 13 shows the basic control state of the clutch control device 40A after system startup. For example, when the ignition is turned on (main switch on, system startup) with the transmission 21 in neutral, the clutch control device 40A is in an automatic clutch control state (auto mode M1) (see a1 in the figure). At this time, the clutch actuator 50 is driven to release (disconnect) the clutch device 26 (see a2 in the figure). From this state, when the transmission 21 is in gear and the throttle is opened, launch control of the motorcycle 1, including half-clutch control, is performed (see a3 in the figure).

[0075] At this time, the clutch control device 40A increases the vehicle speed while operating the clutch device 26 to the engagement side (connection side) with the clutch switch 4c kept off (the clutch lever 4b not being operated) so that the rotational difference between the upstream and downstream sides of the clutch device 26 (clutch rotation difference) converges to 0. The control to release (disconnect) the clutch device 26 when the motorcycle 1 is stopped is performed whether the transmission 21 is in neutral or in gear.

[0076] When automatic clutch control (auto mode M1) is being performed, the driver is notified that automatic clutch control is being performed by, for example, lighting up a first indicator IN1 in the meter device of the motorcycle 1. Furthermore, when a downshift request, which will be described later, is made, the driver is notified by using a second indicator IN2 in the meter device.

[0077] The second indicator IN2 includes a gear position indicator GP and a downshift indicator DN, and the background color can also be changed. For example, when the motorcycle 1 stops with the transmission 21 in a higher gear, the downshift indicator DN lights up and the background color changes to a warning color to alert the rider. When the motorcycle 1 starts with the transmission 21 in a higher gear, the warning color flashes to alert the rider. The second indicator IN2 not only activates when the motorcycle 1 stops and starts, but may also activate while the motorcycle is traveling. For example, the second indicator IN2 may light up or flash the downshift indicator DN to alert the rider to a gear change when the transmission 21 is in an excessively high gear compared to the current vehicle speed.

[0078] When the vehicle is traveling with the clutch engaged (clutch differential rotation 0), automatic clutch control is suspended and the drive of the clutch actuator 50 is stopped (see a4 in the figure). When the vehicle is in automatic clutch control (auto mode M1), the clutch control device 40A turns on the first indicator IN1 regardless of whether the clutch actuator 50 is being driven, thereby allowing the driver to recognize that the vehicle is in automatic clutch control (auto mode M1).

[0079] During automatic clutch control, the driver can change gears in the transmission 21 simply by operating the shift operator (see a5 in the figure). At this time, the shift operation is used as a gear change command, and clutch control and engine cooperative control are executed. After the gear change is completed, the automatic clutch control is again suspended.

[0080] <Automatic Clutch Disengagement Control> Next, the automatic clutch disengagement control of the embodiment will be described with reference to the graphs in Figures 10A and 10B. This control prevents the engine from stalling by automatically switching to a clutch disengagement state when the motorcycle decelerates and attempts to stop with the clutch still engaged.

[0081] The graphs in Figures 10A and 10B show changes over time in main parameters when automatic clutch disengagement control is performed. The lower part of the graph shows the clutch actuation angle (hereinafter simply referred to as clutch angle), the upper part of the graph shows vehicle speed, and the middle part of the graph shows engine speed. The horizontal axis of the graph shows time.

[0082] For example, the clutch angle is an angle detected by the rotation angle sensor 56d, and is a value used to detect the clutch capacity. For example, the rotation angle of the release shaft 53 or the driven clutch lever 54 may be detected as another value used to detect the clutch capacity.

[0083] The automatic clutch disengagement control is performed when the clutch control mode is in the automatic mode M1 or the manual intervention mode M3. Figures 10A and 10B show the automatic clutch disengagement control in the manual intervention mode M3.

[0084] The clutch angle is a parameter related to the clutch capacity, and its control target value (see line L11 in the figure) is calculated, for example, by multiplying the rotation angle of the motor 52 by the reduction ratio of the speed reduction mechanism 51. The control target value shown by line L11 in the figure is the control target value (clutch control target angle) of the clutch angle when the clutch device 26 is operated by the motor 52. Line L12 in the figure indicates the actual measured value of the clutch angle.

[0085] In a normally closed clutch, when the clutch angle is "0", there is no operational input (input to the disengagement side) from the driver or the motor 52 to the clutch device 26, and the clutch capacity is 100%. In other words, when the clutch angle is "0", the clutch device 26 is in an engaged state (fastened state). This state corresponds to area A on the horizontal axis in the figure. In area A, the clutch control target angle L11 is set to be near the default clutch engagement angle θ1.

[0086] Referring to the line VL1 in the upper part of the graph, when the vehicle speed of the motorcycle 1 gradually decreases while the clutch device 26 is in an engaged state and the vehicle speed drops to a first disengagement determination value (first threshold value) V1, automatic clutch disengagement control is initiated at timing t1. At this time, the clutch control target angle L11 changes from the clutch engagement angle θ1 toward the clutch disengagement angle θ2, and the control unit 40 drives the motor 52 to operate the clutch device 26 toward the disengagement side via the release shaft 53, etc. For example, the start timing t1 of the automatic clutch disengagement control is not limited to the timing when the vehicle speed reaches the threshold value, but may also be the timing when the engine rotation speed reaches the threshold value.

[0087] When the clutch angle measurement value L12 reaches the clutch disengagement angle θ2 following the change in the clutch control target angle L11, the clutch device 26 is disengaged. For example, in the automatic clutch disengagement control, after the clutch device 26 is automatically disengaged, the clutch disengagement state is maintained until the throttle is opened or the vehicle speed increases due to a downhill slope or the like and exceeds the first disengagement determination value V1.

[0088] As shown in FIG. 10A , during automatic clutch disengagement control, when the clutch control target angle L11 rises sharply from the clutch engagement angle θ1 to the clutch disengagement angle θ2, the motor 52 is driven to follow the rise of the clutch control target angle L11, causing the actual measured value L12 of the clutch angle to increase sharply. The automatic clutch disengagement control (part B in FIG. 10A ) corresponds to the control performed when the clutch device 26 is disengaged in response to a gear shift operation (shift pedal operation) of the transmission 21. Note that in FIG. 10A , the slope (rate of change) of the clutch angle as it changes from the clutch engagement angle θ1 to the clutch disengagement angle θ2 is equivalent to infinity at the clutch control target angle L11, so the slope of the actual measured value L12 is used as the substantial value. The symbol t1′ in the figure indicates the timing at which the actual measured value L12 becomes the clutch disengagement angle θ2.

[0089] 10A, the clutch device 26 is suddenly disengaged, and a sudden change in the lever reaction force of the clutch lever 4b occurs. This type of behavior can be expected by the driver when shifting gears, but in the case of clutch disengagement control when the vehicle speed is reduced, the clutch lever 4b behaves unexpectedly, which can be uncomfortable for the driver if the driver has their hand on the clutch lever 4b.

[0090] 10B, in the clutch automatic disengagement control of this embodiment, the clutch control target angle L11 is gradually increased from the clutch engagement angle θ1 to the clutch disengagement angle θ2 over a first change time T3 (part C in the figure). By providing the change time T3, the actual clutch angle L12 also increases to roughly coincide with the clutch control target angle L11. In the figure, symbol t2 indicates the timing at which the actual clutch angle L12 becomes the clutch disengagement angle θ2.

[0091] 10A and 10B, the rate of change (slope) of the actual measurement value L12 of each clutch angle is, overall, greater in the slope (rate of change, clutch disengagement speed L12VA) of the actual measurement value L12 in Fig. 10A than in the slope (rate of change, clutch disengagement speed L12VB) of the actual measurement value L12 in Fig. 10B. In other words, the clutch disengagement speed L12VB in the clutch automatic disengagement control in Fig. 10B is set slower than the clutch disengagement speed L12VA in the clutch automatic disengagement control in Fig. 10A.

[0092] The automatic clutch disengagement control of FIG. 10B performs clutch disengagement over the first change time T3, so that the clutch device 26 is gradually disengaged and the reaction force of the clutch lever 4b also changes gradually, making it less likely that the driver will feel uncomfortable.

[0093] In particular, when the control mode is manual, the driver often operates the clutch lever 4b, and therefore has his or her fingers on the clutch lever 4b. Therefore, unintended movement of the clutch lever 4b is likely to cause discomfort to the driver. In the release shaft 53 connected to the clutch lever 4b by the operating cable 54c, when the motor 52 is driven and the intermediate release shaft 63 on the motor side and the lower release shaft 62 on the clutch side rotate, the upper release shaft 61 on the lever side disengages from the lower release shaft 62. As a result, only the reaction force of the return spring acts on the upper release shaft 61, and the operation reaction force of the clutch lever 4b suddenly decreases, causing the clutch lever 4b to move.

[0094] On the other hand, in the automatic clutch disengagement control of the embodiment, the clutch device 26 is gradually disengaged by control using a relaxation angle rate limit, which will be described later, thereby easing the change in the lever reaction force and reducing the sense of discomfort felt by the driver. In addition, by gradually disengaging the clutch device 26, the impact on the vehicle behavior at low speeds can be reduced.

[0095] Figure 11 shows the time changes of parameters when the clutch control mode is in auto mode M1. In auto mode M1, the driver is not operating the clutch, so automatic clutch operation can be prioritized. That is, for example, a second disengagement determination value (second threshold value) V2 higher than the first disengagement determination value V1 can be set for the vehicle speed, and automatic clutch disengagement control can be initiated when the vehicle speed drops to the second disengagement determination value V2 (timing t4). The start timing t4 of the automatic clutch disengagement control in Figure 11 is not limited to the timing when the vehicle speed reaches the threshold value, but may also be the timing when the engine rotation speed reaches the threshold value.

[0096] In this case, the actual clutch angle L12 is gradually increased from the clutch engagement angle θ1 to the clutch disengagement angle θ2 (from timing t4 to timing t2) over a second change time T5 that is longer than the first change time T3 (part D in the figure). This causes the clutch device 26 to be disengaged more gradually, suppressing changes in the lever reaction force and the effect on vehicle behavior, thereby improving the quality of the auto mode M1.

[0097] The example in FIG. 11 is one example of setting multiple vehicle speed thresholds related to the start timing of the clutch automatic disengagement control, and the following configurations are other examples. As another example, the vehicle speed threshold related to the start timing of the clutch automatic disengagement control may be set for each gear of the transmission 21. That is, even if the vehicle speed does not stall in first gear, it is possible that the engine may stall in second gear or higher due to reaction force from the wheels. For this reason, for higher gears, multiple thresholds may be set that are gradually increased, ensuring a longer change time for the higher gears, and starting the clutch automatic disengagement control with ample time to spare. Note that if the transmission 21 is a continuously variable transmission, virtual gears may be set within the operating ranges of appropriate gear shift operating elements, and multiple thresholds may be set in the same manner as above.

[0098] 12 shows the change in parameters over time when the rate of decrease in vehicle speed is large (during rapid deceleration). When the rate of decrease in vehicle speed is large (see line VL2, which has a steeper slope than line VL1), if the clutch is disengaged over the aforementioned change time T3 or T5, the following event is predicted. That is, it is predicted that at least one of the vehicle speed and engine speed (engine speed in this embodiment) will fall below the engine stall determination value (N1) before the clutch is disengaged. In this case, engine stall prevention is prioritized over discomfort suppression, and the clutch is disengaged quickly, as in section B of FIG. 10A.

[0099] Next, the process (clutch disengagement rate limit setting) performed by the control unit 40 when performing automatic clutch disengagement control will be described with reference to the flowchart in Figure 14. The "rate limit setting" is a process for setting one of the following normal angle rate limit, relaxed angle rate limit, and engine stall avoidance angle rate limit.

[0100] First, in step S1, it is determined whether the current clutch control mode is auto mode M1. If step S1 is YES (auto mode M1), the process proceeds to step S2. If step S1 is NO (not auto mode M1), that is, if the mode is manual mode M2 ​​or manual intervention mode M3, rate limit setting is deemed unnecessary (step S8), and the process is temporarily terminated. In manual mode M2, clutch control itself is not performed. In manual intervention mode M3, the clutch is not automatically disengaged; after the conditions for returning to auto mode M1 are met during manual intervention mode M3, the clutch is disengaged after returning to auto mode M1.

[0101] In step S2, it is determined whether the vehicle speed is decreasing. If the answer is YES in step S2 (vehicle speed is decreasing), the process proceeds to step S3. If the answer is NO in step S2 (vehicle speed is not decreasing), the clutch automatic disengagement control is control using the normal angle rate limit (step S7). The "control using the normal angle rate limit" corresponds to part B in FIG. 10A (control during gear shifting). The "normal angle rate limit" indicates the upper limit of the rate of decrease (decrease rate) per time of the control target value of the clutch angle (clutch control target angle). The normal angle rate limit in this embodiment is greater than the relaxation angle rate limit, which will be described later.

[0102] In step S3, it is determined whether the vehicle speed is equal to or greater than the rate change determination threshold W1. The rate change determination threshold W1 is a value determined in advance through testing or the like as a value at which clutch disengagement can be completed without engine stalling even when automatic clutch disengagement control is performed using the relaxation angle rate limit. If the answer is YES in step S3 (vehicle speed is equal to or greater than the rate change determination threshold W1 (vehicle speed is still high)), automatic clutch disengagement control is performed using the relaxation angle rate limit (step S4). In this case, since the clutch device is already in a disengaged state, step S5 is essentially completed. If the answer is NO in step S3 (vehicle speed is equal to or greater than the rate change determination threshold W1 (vehicle speed is low)), proceed to step S5.

[0103] In step S5, it is determined whether the rate of decrease in engine speed is equal to or greater than the engine stall avoidance threshold W2. The engine stall avoidance threshold W2 is a value determined in advance through testing or the like as a value indicating a high possibility of engine stall when the vehicle speed is lower than the rate change determination threshold W1. Referring to FIGS. 10B and 11, for example, the determination in step S5 corresponds to a determination of whether the engine speed is predicted to be equal to or less than the engine stall determination value N1 when the clutch is disengaged using the aforementioned change time T3 or T5, based on the rate of decrease in engine speed. Note that in the patterns shown in each figure, the engine speed after clutch disengagement becomes the idle speed N2.

[0104] If the answer to step S5 is YES (the rate of decrease in engine speed is equal to or greater than the engine stall avoidance determination threshold W2 (a rapid decrease)), the clutch automatic disengagement control is performed using the engine stall avoidance angle rate limit (step S6). The "control using the engine stall avoidance angle rate limit" is the control corresponding to part B in FIG. 10A (control during gear shifting), similar to the "control using the normal angle rate limit" described above, and the clutch is disengaged quickly. The normal angle rate limit is set slower than the engine stall avoidance angle rate limit and the relaxation angle rate limit. The engine stall avoidance angle rate limit and the normal angle rate limit may be the same or may be different depending on the specifications. This makes it possible to avoid the possibility of an engine stall. If the answer to step S5 is NO (the rate of decrease in engine speed is less than the engine stall avoidance determination threshold W2 (a gradual decrease)), the process proceeds to step S4, where the clutch automatic disengagement control is performed using the relaxation angle rate limit. "Control using relaxed angle rate limit" corresponds to part C in FIG. 10B and part D in FIG. 11, and can be said to be "control using angle rate limit for improving lever feeling."

[0105] The "relaxation angle rate limit" is an upper limit on the rate of decrease of the clutch control target angle, and is smaller than the normal angle rate limit described above. By using the relaxation angle rate limit to perform automatic clutch disengagement control, the clutch control target angle is gradually increased to disengage the clutch device 26, suppressing the behavior of the clutch lever 4b and reducing the driver's discomfort even when the driver has their hand on the clutch lever. This also reduces the electrical energy required to drive the motor 52, the deviation between the target value and the actual measured value of the clutch angle, and the overshoot of the actual measured value of the clutch angle.

[0106] <Processing After Manual Intervention> Next, the processing performed by the control unit 40 when performing auto mode return control after manual intervention will be described with reference to the flowchart in Fig. 15. First, in step S11, it is determined whether the clutch control mode is manual intervention mode M3. If the answer is YES in step S11 (the clutch control mode is manual intervention mode M3), the process proceeds to step S12. If the answer is NO in step S11 (the clutch control mode is not manual intervention mode M3) (for example, if the mode selector switch 49 has been operated to manual mode M2), the auto mode return control is not performed, and the process proceeds to engine stall avoidance determination in step S19.

[0107] In step S12, it is determined whether the clutch differential rotation has converged (whether it is less than the differential rotation threshold Ne1). This determination corresponds to determining whether there is no clutch differential rotation (the clutch is in an engaged state). If the determination in step S12 is YES (the clutch differential rotation has converged), the process proceeds to step S13. If the determination in step S12 is NO (the clutch differential rotation has not converged), the auto mode return control is not performed, and the process proceeds to step S19 for determining whether to prevent an engine stall. If the clutch differential rotation has not converged, the process corresponds to a state in which the clutch device 26 is slipping due to a partial clutch, etc.

[0108] In step S13, it is determined whether the clutch switch 4c is off (whether the clutch lever 4b is not being operated). If the result in step S13 is YES (the clutch lever 4b is not being operated), the process proceeds to step S14. If the result in step S13 is NO (the clutch lever 4b is being operated), the auto mode return control is not performed, and the process proceeds to step S19 for engine stall avoidance determination.

[0109] In step S14, it is determined whether the vehicle speed is equal to or greater than a first threshold value V1. The vehicle speed threshold value V1 in step S14 is a value that marks the boundary between the low vehicle speed region and the medium vehicle speed region, and corresponds to, for example, 1600 rpm in engine speed. In step S14, the clutch differential rotation has converged and the clutch lever 4b is not being operated, so the vehicle speed is proportional to the engine speed. Therefore, although gear information for the transmission 21 is also required, step S14 can be replaced by determining whether the engine speed is equal to or greater than a threshold value. If step S14 is YES (the vehicle speed is equal to or greater than the first threshold value V1), the process proceeds to step S15. If step S14 is NO (the vehicle speed is less than the first threshold value V1), the process proceeds to step S17.

[0110] In step S15, it is determined whether the return time T has elapsed a first return time T1. When the vehicle speed is equal to or greater than a first threshold value V1, the first return time T1 is set to, for example, 1 second. In the medium vehicle speed range (e.g., 1600 rpm or higher), the driver is less likely to operate the clutch device 26 than in the low vehicle speed range (e.g., less than 1600 rpm). Therefore, even if the vehicle returns to auto mode M1 in a short time, the driver is less likely to feel uncomfortable. If the answer is YES in step S15 (the first return time T1 has elapsed), the process proceeds to step S16, where auto mode return control is performed. If the answer is NO in step S15 (the first return time T1 has not elapsed), the process is temporarily terminated without performing auto mode return control.

[0111] In step S17, it is determined whether the throttle is closed (whether there is no intention to drive). In the low vehicle speed range (for example, less than 1600 rpm), there is a higher possibility that the driver will continue to operate the clutch device 26 than in the medium vehicle speed range (for example, 1600 rpm or more). Therefore, unconditionally returning to auto mode M1 may affect the clutch operation of the driver, causing discomfort. If the answer is YES in step S17 (no intention to drive), the process proceeds to step S18. If the answer is NO in step S17 (intent to drive), the auto mode return control is not performed, and the process proceeds to step S19 for engine stall avoidance determination.

[0112] In step S18, it is determined whether a second return time T2, which is longer than the first return time T1, has elapsed while the throttle is closed. If the result in step S18 is YES (the second return time T2 has elapsed), it is determined that the driver has no intention of operating the clutch device 26, and the process proceeds to step S16, where auto mode return control is performed. If the result in step S18 is NO (the second return time T2 has not elapsed), the process proceeds to step S19, where an engine stall avoidance determination is made.

[0113] <Engine stall avoidance determination> Next, with reference to the flowchart in Figure 16, we will explain the processing performed by the control unit 40 when disengaging the clutch using the engine stall avoidance angle rate limit if there is a possibility of engine stall when the recovery conditions are not satisfied in manual intervention mode M3.

[0114] First, in step S21, it is determined whether the vehicle speed is equal to or greater than the rate change determination threshold W1. If the result in step S21 is YES (the vehicle speed is equal to or greater than the rate change determination threshold W1 (the vehicle speed is still high)), it is determined that rate limit setting is not necessary (step S22), and the process is temporarily terminated. If the result in step S21 is NO (the vehicle speed is equal to or greater than the rate change determination threshold W1 (the vehicle speed is low)), the process proceeds to step S23.

[0115] In step S23, it is determined whether the vehicle speed is equal to or greater than the rate change determination threshold W1. If the result in step S21 is YES (the vehicle speed is equal to or greater than the rate change determination threshold W1 (the vehicle speed is still high)), it is determined that rate limit setting is not necessary (step S22), and the process is temporarily terminated. If the result in step S21 is NO (the vehicle speed is equal to or greater than the rate change determination threshold W1 (the vehicle speed is low)), the process proceeds to step S23.

[0116] In step S23, it is determined whether the rate of decrease in engine speed is equal to or greater than the engine stall avoidance determination threshold W2. If the result in step S23 is YES (the rate of decrease in engine speed is equal to or greater than the engine stall avoidance determination threshold W2 (a rapid decrease)), automatic clutch disengagement control is performed even in manual intervention mode M3 (step S24). In this way, even if the clutch control mode is manual, clutch control can be intervened to avoid the possibility of engine stall. If the result in step S23 is NO (the rate of decrease in engine speed is less than the engine stall avoidance determination threshold W2 (a gradual decrease)), rate limit setting is deemed unnecessary (step S22), and the process is temporarily terminated.

[0117] As described above, the clutch control device 40A of the present invention is a clutch control device 40A that includes a clutch device 26 that connects and disconnects power transmission between the engine 13 and transmission 21 of the motorcycle 1, a clutch actuator 50 that operates the clutch device 26, and a control unit 40 that controls the drive of the clutch actuator 50, and the control unit 40 performs automatic clutch disengagement control that automatically disconnects the clutch device 26 when shifting gears and when the vehicle speed is reduced, and sets the clutch disengagement speed L12VB of the automatic clutch disengagement control when the vehicle speed is reduced (the rate of change of the actual measured value L12 of the clutch angle in Figure 10B) to be slower than the clutch disengagement speed L12VA of the automatic clutch disengagement control when shifting gears (the rate of change of the actual measured value L12 of the clutch angle in Figure 10A). According to this configuration, by setting the clutch disengagement speed L12VB of the clutch automatic disengagement control when the vehicle speed decreases slower than the clutch disengagement speed L12VA of the clutch automatic disengagement control when shifting gears, it is possible to prevent the clutch operator that the driver touches from moving unexpectedly due to sudden clutch disengagement control, and to prevent any discomfort that may occur when the clutch automatic disengagement control is performed when the vehicle speed decreases.

[0118] In the clutch control device 40A of the present invention, the automatic clutch disengagement control when the vehicle speed decreases is performed at a disengagement speed of either a relaxation angle rate limit that is set when the rate of decrease in vehicle speed or engine speed is less than a specified engine stall avoidance determination threshold W2, or an engine stall avoidance angle rate limit that is set when the rate of decrease in vehicle speed or engine speed is equal to or greater than the engine stall avoidance determination threshold W2, and the relaxation angle rate limit is set slower than the engine stall avoidance angle rate limit. With this configuration, by setting the relaxation angle rate limit and the engine stall avoidance angle rate limit to have different speeds and switching between them depending on the rate of decrease in vehicle speed or engine speed, it is possible to achieve both an improved lever feel and the avoidance of engine stalls.

[0119] In the clutch control device 40A of the present invention, the control unit 40 has an automatic control mode M1 in which the clutch device 26 is automatically actuated by driving the clutch actuator 50, and a manual control intervention mode M3 in which the clutch device 26 is manually actuated by inputting an operation to the clutch operator 4b, and if a predetermined condition for returning to the automatic control mode M1 is satisfied during control in the manual control intervention mode M3, the control unit 40 automatically returns to the automatic control mode M1. According to this configuration, if a predetermined condition for returning to the automatic control mode is satisfied during control in the manual control intervention mode M3, the control unit 40 automatically returns to the automatic control mode M1, thereby preventing the driver from mistaking the control mode and performing a gear change operation (especially, operating in gear without operating the clutch despite being in the manual control intervention mode M3), thereby avoiding engine stalls due to forgetting to disengage the clutch and improving operability.

[0120] In the clutch control device 40A of the present invention, when the vehicle speed or engine rotational speed drops to a prescribed rate change determination threshold W1 in the manual control intervention mode M3, and the rate of decrease in the vehicle speed or engine rotational speed is equal to or greater than a prescribed engine stall avoidance determination threshold W2, automatic clutch disengagement control is performed at the engine stall avoidance clutch disengagement speed. According to this configuration, when the vehicle speed or engine rotational speed is less than the rate change determination threshold W1 and the rate of decrease in the vehicle speed or engine rotational speed is equal to or greater than the engine stall avoidance determination threshold W2, automatic clutch disengagement is performed at a relatively fast engine stall avoidance clutch disengagement speed, thereby making it possible to prevent engine stalls due to delays in automatic clutch disengagement.

[0121] In the clutch control device 40A of the present invention, the automatic clutch disengagement control during a vehicle speed decrease is performed when the vehicle speed becomes equal to or lower than threshold values ​​V1 and V2, and the first threshold value V1 for determining the execution of the automatic clutch disengagement control in the manual control intervention mode M3 is set lower than the second threshold value V2 for determining the execution of the automatic clutch disengagement control in the automatic control mode M1. According to this configuration, by setting the threshold value V1 for determining the execution of clutch disengagement in the manual control intervention mode M3 lower than the threshold value V2 for determining the execution of clutch disengagement in the automatic control mode M1, it is possible to respect the driver's intentions as much as possible in the manual control intervention mode M3 and to facilitate an improvement in the lever feeling in the automatic control mode M1.

[0122] In the clutch control device 40A of the present invention, the automatic clutch disengagement control when the vehicle speed decreases is initiated when a specified parameter (vehicle speed) reaches a threshold value (disengagement determination values ​​V1, V2), and the threshold value varies depending on the gear position of the transmission 21 of the motorcycle 1. With this configuration, the start timing of the automatic clutch disengagement control when the vehicle speed decreases varies depending on the gear position of the transmission, making it possible to set the automatic clutch disengagement control to start earlier (when the vehicle speed is high) for higher gear positions, for example. This increases the reliability of engine stall prevention.

[0123] The clutch control device 40A of the present invention notifies the driver to prompt a gear change operation when the gear position of the transmission 21 is on the higher side relative to the vehicle speed. With this configuration, by notifying the driver when the gear position of the transmission 21 is high relative to the vehicle speed, it is possible to increase the likelihood of a downshift and, in particular, to increase the certainty that the gear position will be returned to a low gear equivalent by the time the vehicle comes to a stop. This reduces the possibility of starting in a higher gear position and suppresses deterioration of the clutch device.

[0124] The present invention is not limited to the above embodiment. For example, the clutch operator is not limited to the clutch lever 4b, but may be a clutch pedal or various other operators. The clutch device 26 may be a normally open clutch that is normally disengaged when there is no external input. The clutch device 26 is not limited to being disposed between the engine 13 and the transmission 21, but may be disposed between a prime mover and any output target other than the transmission. The prime mover is not limited to being an internal combustion engine, but may also be an electric motor.

[0125] The application of the clutch control device 40A of the present embodiment is not limited to saddle-ride vehicles in which clutch operation is automated. For example, the present embodiment can also be applied to saddle-ride vehicles that, while based on manual clutch operation, allow gear changes by adjusting driving force without manual clutch operation under certain conditions (saddle-ride vehicles equipped with a so-called clutch-less transmission). The clutch control device 40A of the present embodiment may also be applied to saddle-ride vehicles other than motorcycles. The saddle-ride vehicle includes all vehicles on which a driver straddles the vehicle body, including not only motorcycles (including motorized bicycles and scooters), but also three-wheeled vehicles (including vehicles with one front wheel and two rear wheels, as well as vehicles with two front wheels and one rear wheel) and four-wheeled vehicles (such as four-wheeled buggies). The present embodiment may also be applied to vehicles that include an electric motor as a prime mover. The present embodiment may also be applied to vehicles other than saddle-ride vehicles (such as passenger cars, buses, and trucks).

[0126] Although the clutch control device 40A of this embodiment is applied to a vehicle, the present invention is not limited to application to vehicles and may be applied to various vehicles and moving objects, such as various transportation equipment such as aircraft and ships, as well as construction machinery and industrial machinery. Furthermore, the present invention can be widely applied to equipment other than vehicles that is equipped with a clutch control device, such as push lawn mowers and cleaning machines. The configuration of the above embodiment is an example of the present invention, and various modifications are possible within the scope of the gist of the present invention, such as replacing the components of the embodiment with well-known components.

[0127] REFERENCE SIGNS LIST 1 Motorcycle (vehicle) 4b Clutch lever (clutch operator) 13 Engine (internal combustion engine, prime mover) 21 Transmission (output target) 26 Clutch device 40 Control unit 40A Clutch control device 50 Clutch actuator L12VA, L12VB Clutch disengagement speed (change rate of actual measurement value of clutch angle) M1 Automatic control mode, auto mode M2 ​​Manual control mode, manual mode M3 Manual control intervention mode, manual intervention mode V1, V2 Threshold W1 Rate change determination threshold W2 Engine stall avoidance determination threshold

Claims

1. a clutch device (26) that connects and disconnects power transmission between a prime mover (13) of the vehicle (1) and an output target (21); a clutch actuator (50) for actuating the clutch device (26); A clutch control device (40A) including a control unit (40) that controls the drive of the clutch actuator (50), The control unit (40) performs automatic clutch disengagement control to disengage the clutch device (26) when shifting gears and when the vehicle speed is reduced, and makes a clutch disengagement speed (L12VB) of the automatic clutch disengagement control when the vehicle speed is reduced slower than a clutch disengagement speed (L12VA) of the automatic clutch disengagement control when shifting gears, The control unit (40) an automatic control mode (M1) in which the clutch device (26) is automatically operated by driving the clutch actuator (50); a manual control intervention mode (M3) in which the clutch device (26) is manually operated by inputting an operation to a clutch operator (4b) operated by a driver, When the vehicle speed or engine speed drops to a specified rate change judgment threshold (W1) in the manual control intervention mode (M3), and the rate of decrease in the vehicle speed or engine speed is equal to or greater than a specified engine stall avoidance judgment threshold (W2), the clutch control device performs automatic clutch disengagement control at a clutch disengagement speed that is faster than when the rate of decrease is less than the engine stall avoidance judgment threshold (W2).

2. The automatic clutch disengagement control when the vehicle speed decreases is a mitigation clutch disengagement speed that is set when the rate of decrease in vehicle speed or engine rotation speed is less than the engine stall avoidance determination threshold value (W2); a stall avoidance clutch disengagement speed that is set when the rate of decrease of the vehicle speed or engine rotation speed is equal to or greater than the stall avoidance determination threshold value (W2), 2. The clutch control device according to claim 1, wherein the mitigation clutch disengagement speed is set slower than the engine stall prevention clutch disengagement speed.

3. The control unit (40) 3. The clutch control device according to claim 1, wherein the automatic control mode (M1) is automatically restored when a specified condition for restoring the automatic control mode (M1) is satisfied during control in the manual control intervention mode (M3).

4. (delete)

5. The automatic clutch disengagement control when the vehicle speed decreases is performed when the vehicle speed becomes equal to or lower than a threshold value (V1, V2), 2. The clutch control device according to claim 1, wherein a first threshold value (V1) for determining whether the clutch automatic disengagement control is to be performed in the manual control intervention mode (M3) is set lower than a second threshold value (V2) for determining whether the clutch automatic disengagement control is to be performed in the automatic control mode (M1).

6. The automatic clutch disengagement control during a decrease in vehicle speed is initiated when a specified parameter reaches a threshold value (V1, V2), 3. The clutch control device according to claim 1, wherein the threshold values ​​(V1, V2) vary depending on the gear position of the transmission (21) of the vehicle (1).

7. 7. The clutch control device according to claim 6, wherein when the gear position of the transmission (21) is on the high-speed side relative to the vehicle speed, a notification is given to prompt the driver to perform a gear change operation.