Clutch system

Abstract

To properly bring a clutch in a disengaged state into an engaged state.SOLUTION: The clutch system S includes a clutch 110 in which a clutch disk 112 and a flywheel 111 are in a connected state, a control valve 120 that supplies hydraulic oil 121 to the clutch 110, and a supply control unit 222 that supplies a current from a power supply 130 to the control valve 120. After supplying the current of the first current A1 to the control valve 120, the control unit 222 sets the current to a second current A1 smaller than the first current A2, and after setting the current to the second current A2, reduces the current with the lapse of time so as to set the current to a third current A2 smaller than the second current A3 at the timing when the clutch 110 in the disconnected state enters the connected state.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a clutch system for connecting or disconnecting the transmission of power. [Background technology]

[0002] Clutches that connect or disconnect the transmission of power are known. Patent Document 1 discloses a technology in which hydraulic oil is supplied to a hydraulically operated clutch to switch a disconnected clutch to a connected state. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-241244 Summary of the Invention [Problem to be solved by the invention]

[0004] The clutch disc of a hydraulically operated clutch moves at a speed that corresponds to the hydraulic pressure of the hydraulic oil supplied to the clutch. Therefore, if the hydraulic oil pressure supplied to the clutch is high when the clutch disc connected to the input shaft is brought into contact with the plate on the flywheel side, the clutch disc will come into contact with the plate on the flywheel side at a high speed, resulting in a large shock when the clutch disc and the plate on the flywheel side come into contact. On the other hand, if the hydraulic oil pressure supplied to the clutch is low, the clutch disc will move slower, and it will take a long time for the clutch disc to come into contact with the plate on the flywheel side.

[0005] The present invention has been made in consideration of these points, and has as its object to properly bring a clutch that is in a disengaged state into an engaged state. [Means for solving the problem]

[0006] In one aspect of the present invention, there is provided a clutch system comprising: a clutch having a clutch disc that is movable in the direction of the rotational axis of a flywheel connected to a power unit; when hydraulic oil is supplied, the clutch disc moves toward the flywheel at a speed corresponding to the amount of hydraulic oil, thereby bringing the clutch disc into contact with the flywheel; a control valve that supplies the hydraulic oil to the clutch in an amount corresponding to the current value of a current supplied from a power source; and a supply control unit that, when bringing the clutch into a disconnected state in which the clutch disc and the flywheel are not in contact with each other, supplies the current of a first current value to the control valve, and after supplying the current of the first current value to the control valve, changes the current value of the current to be supplied to the control valve to a second current value that is smaller than the first current value, and after changing the current value to the second current value, decreases the current value of the current over time so that the current value reaches a third current value that is smaller than the second current value at the time the clutch in the disconnected state is brought into the connected state.

[0007] The timing may be a second point in time at which a time has elapsed from a first point in time at which the supply of the current of the first current value to the control valve begins until the clutch disc of the clutch in the disengaged state comes into contact with the flywheel.

[0008] The supply control unit may reduce the current value of the current by a ratio of the difference between the second current value and the third current value relative to the time from a third point in time at which the current value of the current is set to the second current value to the second point in time.

[0009] When the clutch in the disengaged state is switched to the engaged state, if the difference in rotation speed between the flywheel in the disengaged state and the flywheel rotation speed after the clutch is switched to the engaged state is equal to or greater than a judgment value for determining that an impact has occurred at the time of contact, the supply control unit may change the second current value when the clutch is next switched from the disengaged state to the engaged state.

[0010] When the rotation speed difference detected is equal to or greater than the determination value, the supply control unit may increase the amount of change in the second current value as the rotation speed difference increases.

[0011] When an amount of change in the second current value according to the rotation speed difference is equal to or greater than a predetermined current value, the supply control unit may change the second current value by a correction amount smaller than the amount of change.

[0012] The supply control unit may reduce the second current value when the clutch is next changed from the disengaged state to the engaged state if the time at which the rotation speed difference greater than or equal to the judgment value is detected occurs before the timing, and may increase the second current value when the clutch is next changed from the disengaged state to the engaged state if the time at which the rotation speed difference greater than or equal to the judgment value is detected occurs after the timing.

[0013] The supply control unit may change the second current value when the number of times the rotation speed difference equal to or greater than the determination value is detected is equal to or greater than a determination number for determining whether to change the second current value. [Effects of the Invention]

[0014] According to the present invention, an effect is achieved in that a clutch that is in a disengaged state can be appropriately brought into an engaged state. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 2 is a diagram illustrating the configuration of a clutch system. [Figure 2] FIG. 2 is a schematic diagram of a clutch in an engaged state. [Figure 3] 10A and 10B are diagrams for explaining a process of switching a clutch from a disengaged state to an engaged state; [Figure 4] FIG. 10 is a diagram for explaining a process for advancing the actual timing. [Figure 5] FIG. 10 is a diagram for explaining a process of delaying the actual timing. DETAILED DESCRIPTION OF THE INVENTION

[0016] [Configuration of Clutch System S] 1 is a diagram illustrating the configuration of a clutch system S. The clutch system S is a system that connects or disconnects the transmission of power between a power unit 100 and a power transmission member. The clutch system S is mounted on, for example, a vehicle. The clutch system S includes the power unit 100, a clutch 110, a control valve 120, a power source 130, a pump 140, a sensor 150, and a supply control device 200.

[0017] The power unit 100 supplies power to a vehicle equipped with the clutch system S. The power unit 100 is, for example, an engine, but may also be a motor.

[0018] The clutch 110 connects or disconnects the transmission of power between a power transmission member (not shown) and the power unit 100. The power transmission member is, for example, a speed change mechanism. The speed change mechanism changes the torque and rotation speed of the power of the power unit 100 to transmit the power to the wheels of the vehicle. The clutch 110 has a flywheel 111 and a clutch disc 112. As shown in Figure 1, the clutch 110 is in a disconnected state when the flywheel 111 and the clutch disc 112 are not in contact with each other.

[0019] The flywheel 111 is connected to the output shaft 101 of the power unit 100 .

[0020] The clutch disc 112 contacts the flywheel 111 to transmit the power of the power unit 100 to the power transmission member. When hydraulic oil 121 is supplied to the clutch disc 112, it moves in the direction of the rotational axis of the flywheel 111. The rotational axis direction is parallel to the axial direction 113 of the output shaft 101. The clutch disc 112 contacts the flywheel 111 by moving in the axial direction 113 in a direction toward the flywheel 111. The state in which the clutch disc 112 and the flywheel 111 are in contact is said to be the engaged state of the clutch 110. Figure 2 is a schematic diagram of the clutch 110 in the engaged state. When the clutch 110 is in the engaged state, it can transmit the power of the power unit 100 to the power transmission member.

[0021] The control valve 120 adjusts the amount of hydraulic oil 121 supplied to the clutch 110. The control valve 120 supplies the amount of hydraulic oil 121 corresponding to the current value of the current supplied from the power source 130 to the clutch disc 112 of the clutch 110. When the clutch disc 112 receives the supply of hydraulic oil 121, it moves at a speed corresponding to the amount of hydraulic oil 121. Specifically, the clutch disc 112 receives pressure corresponding to the amount of hydraulic oil 121 supplied, and moves in the axial direction 113 toward the flywheel 111 at a speed corresponding to the received pressure.

[0022] The power supply 130 supplies current to the control valve 120. The power supply 130 is, for example, at least one of a generator that generates electricity using the power of the power unit 100 and a battery, but may be both, and is not limited to these.

[0023] The pump 140 supplies the hydraulic oil 121 stored in the tank 141 to the control valve 120. The pump 140 is, for example, a centrifugal pump, an axial flow pump, a gear pump, or the like. The pump 140 is driven by the power of the power unit 100, for example, but may also be driven by the electric power of the power source 130. The pump 140 may be any pump that can supply the hydraulic oil 121 to the control valve 120.

[0024] The sensor 150 detects the rotation speed of the flywheel 111. For example, the sensor 150 detects the rotation speed of the output shaft 101 that connects the flywheel 111 and the power unit 100 as the rotation speed of the flywheel 111. A known sensor that can detect the rotation speed of the output shaft 101 can be used as the sensor 150. The sensor 150 detects the rotation speed of the flywheel 111 at predetermined intervals. The predetermined interval is, for example, 10 milliseconds, but is not limited to this.

[0025] The supply control device 200 has a storage unit 210 and a control unit 220. The storage unit 210 is a storage medium including a ROM (Read Only Memory), a RAM (Random Access Memory), a hard disk, etc. The storage unit 210 stores a program executed by the control unit 220.

[0026] The control unit 220 is a computational resource including a processor such as a CPU (Central Processing Unit). The control unit 220 executes a program stored in the storage unit 210 to realize functions as an acquisition unit 221 and a supply control unit 222.

[0027] The acquisition unit 221 acquires the rotation speed of the flywheel 111. For example, the acquisition unit 221 acquires the rotation speed detected by the sensor 150. Specifically, the acquisition unit 221 acquires a first rotation speed of the flywheel 111 when the clutch 110 is in a disengaged state. More specifically, the acquisition unit 221 acquires the rotation speed detected when the power of the power unit 100 is not being transmitted to the power transmission member as the first rotation speed in the disengaged state. The acquisition unit 221 also acquires a second rotation speed of the flywheel 111 after the clutch 110 is in an engaged state. Specifically, the acquisition unit 221 acquires the rotation speed detected when the power of the power unit 100 is being transmitted to the power transmission member as the second rotation speed after the clutch 110 is in an engaged state.

[0028] The supply control unit 222 causes the power source 130 to supply current to the control valve 120. When the supply control unit 222 causes the power source 130 to supply current to the control valve 120, the hydraulic oil 121 is supplied to the clutch disc 112. When the hydraulic oil 121 is supplied to the clutch disc 112, the clutch disc 112 moves in a direction approaching the flywheel 111. Then, when the clutch disc 112 comes into contact with the flywheel 111, the clutch 110, which is in a disengaged state, becomes engaged.

[0029] The clutch disc 112 moves at a speed that depends on the amount of hydraulic oil 121 supplied to the clutch disc 112. Therefore, when a large amount of hydraulic oil 121 is supplied to the clutch disc 112, the clutch disc 112 comes into contact with the flywheel 111 at a high speed, resulting in a large shock when the clutch disc 112 comes into contact with the flywheel 111. On the other hand, when a small amount of hydraulic oil 121 is supplied to the clutch disc 112, the hydraulic pressure applied to the clutch disc 112 decreases. When the hydraulic pressure applied to the clutch disc 112 is small, the moving speed of the clutch disc 112 decreases, resulting in a long movement time until the clutch disc 112 comes into contact with the flywheel 111.

[0030] Therefore, the supply control unit 222 controls the current value of the current output by the power supply 130 so that the clutch 110 in the disengaged state is appropriately brought into the engaged state. For example, the supply control unit 222 supplies a relatively large current value to the control valve 120, and then gradually reduces the current value so that the speed of the clutch disc 112 becomes an appropriate speed at the time of contact between the clutch disc 112 and the flywheel 111. In this way, the supply control unit 222 can reduce the shock at the time of contact and shorten the time it takes for the clutch 110 in the disengaged state to be brought into the engaged state. Below, a process for bringing the clutch 110 in the disengaged state into the engaged state will be described.

[0031] 3 is a diagram for explaining the process of switching the disengaged clutch 110 to the engaged state. The horizontal axis of FIG. 3 represents time T, and the vertical axis represents the current value [mA] of the current supplied from the power supply 130 to the control valve 120. The process of switching the disengaged clutch 110 to the engaged state is started when the supply control unit 222 receives a connection instruction to switch the disengaged clutch 110 to the engaged state. The connection instruction is output, for example, from a control device that controls the traveling of the vehicle. An example of the control device is a gear change control device that controls the traveling gear of the vehicle, but is not limited to this.

[0032] Until receiving a connection instruction, the supply control unit 222 sets the current value of the current supplied from the power supply 130 to the control valve 120 to a standby current value A0. The standby current value A0 is, for example, 10 mA, but is not limited to this.

[0033] Upon receiving the connection instruction, the supply control unit 222 sets the current value of the current supplied from the power supply 130 to the control valve 120 to a first current value A1. A first time point t1 is the time when the supply control unit 222 sets the current value to the first current value A1 and is the time when supply of the current at the first current value A1 to the control valve 120 begins. The first current value A1 is greater than the standby current value A0. The value of the first current value A1 is determined based on the specifications of the control valve 120 and experiments. A specific value of the first current value A1 is, for example, 800 mA, but is not limited to this. The supply control unit 222 continues to set the current value of the current supplied from the power supply 130 to the control valve 120 to the first current value A1 until a first time 310 has elapsed from the first time point t1.

[0034] After supplying a current of the first current value A1 to the control valve 120, the supply control unit 222 changes the current value to a second current value A2. The second current value A2 is smaller than the first current value A1. For example, the second current value A2 is equal to or less than half the magnitude of the first current value A1. A specific value of the second current value A2 is, for example, 300 mA, but is not limited to this. The supply control unit 222 changes the current value to the second current value A2 at a third time point t3, which is when a first time 310 has elapsed since the first time point t1. The first time 310 is determined in advance through experiments or the like, for example, 60 milliseconds, but is not limited to this. The third time point t3 is the time when the supply control unit 222 changes the current value to the second current value A2 and when the supply of the current of the second current value A2 to the control valve 120 begins.

[0035] The supply control unit 222 sets the current value to a second current value A2 and then gradually decreases the current value to a third current value A3. The third current value A3 is smaller than the second current value A2. The third current value A3 is a current value at which the magnitude of the shock generated when the clutch disc 112 contacts the flywheel 111 is equal to or smaller than a predetermined magnitude. A specific value of the third current value A3 is, for example, 90 mA, but is not limited thereto. The magnitude of the shock is defined, for example, by a change in the rotation speed of the flywheel 111. Specifically, the magnitude of the shock is defined by the difference between a first rotation speed of the flywheel 111 in a disengaged state and a second rotation speed of the flywheel 111 after the clutch 110 is engaged. In other words, the third current value A3 is determined through experiments or the like so that the difference between the first rotation speed and the second rotation speed is equal to or smaller than a predetermined magnitude.

[0036] The supply control unit 222 reduces the current value over time so that the current value reaches the third current value A3 at a predetermined timing after the current value reaches the second current value A2. The predetermined timing is a reference timing at which the clutch 110 in the disengaged state is engaged. Specifically, the reference timing is a timing at which the clutch disc 112 in the disengaged state reaches the second time point t2, which is the time elapsed from the first time point t1 until the clutch disc 112 in the disengaged state comes into contact with the flywheel 111. The reference timing is determined based on the time required for a gear shift of a vehicle equipped with the clutch system S. In this embodiment, the time from the first time point t1 to the second time point t2 is 200 milliseconds, but is not limited to this.

[0037] The supply control unit 222 reduces the current value over time at a rate based on the difference between the second current value A2 and the third current value A3. Specifically, the supply control unit 222 reduces the current value over time at a rate based on the difference between the second current value A2 and the third current value A3 for the second time 320 from the third time point t3, when the current value of the current is set to the second current value A2, to the second time point t2. Rate = (second current value A2 - third current value A3) / (second time 320). In this embodiment, the rate is (300 - 90) [mA] / (140) [milliseconds], which is 1.5 [mA / millisecond], but is not limited to this.

[0038] In this way, the supply control unit 222 can increase the amount of hydraulic oil 121 supplied to the control valve 120 compared to when the third current value A3 is continuously supplied from the power source 130 to the control valve 120 from the third time point t3 to the second time point t2. As a result, the movement speed of the clutch disc 112 increases, and the supply control unit 222 can shorten the time it takes for the clutch disc 112 to come into contact with the flywheel 111.

[0039] Furthermore, if the current value is set to the third current value A3 as the second time point t2 approaches, the clutch disc 112 may not be able to decelerate in time, and may come into contact with the flywheel 111 at a high speed. In response to this, the supply control unit 222 reduces the current value over time, thereby slowing down the movement speed of the clutch disc 112 over time. This allows the supply control unit 222 to prevent the clutch disc 112 from coming into contact with the flywheel 111 at a high speed, thereby suppressing the occurrence of shock.

[0040] When the clutch 110 is disengaged, the clutch disc 112 rotates at the same rotation speed as the wheels connected to the clutch disc 112 via the transmission. On the other hand, when the clutch 110 is disengaged, the flywheel 111 rotates at the same rotation speed as the power unit 100. If the clutch disc 112 and the flywheel 111 come into contact with each other while their rotation speeds are different, a contact shock occurs, which changes the rotation speed of the flywheel 111. For this reason, the clutch disc 112 and the flywheel 111 are synchronized so that their rotation speeds are the same when they come into contact. Synchronization control is, for example, a control that sets the rotation speed of the flywheel 111 to the rotation speed of the clutch disc 112, which is rotating at the same rotation speed as the wheels at a reference timing, on the assumption that the clutch disc 112 will come into contact with the flywheel 111 at a reference timing.

[0041] However, the moving speed of the clutch disc 112 changes due to changes in the viscosity and volume of the hydraulic oil 121 caused by changes in temperature, variations in the manufacturing process of the clutch 110, etc. Therefore, the actual timing at which the clutch disc 112 contacts the flywheel 111 may be earlier or later. If the actual timing is earlier or later than the reference timing, the clutch disc 112 contacts the flywheel 111 without synchronizing the rotation speed of the flywheel 111 with the rotation speed of the clutch disc 112, causing a change in the rotation speed of the flywheel 111 and a contact shock.

[0042] Therefore, when a contact shock occurs, supply control unit 222 changes second current value A2 to change the actual timing at which clutch 110 enters the contact state. For example, when the actual timing is later than the reference timing, supply control unit 222 increases second current value A2 to advance the actual timing.

[0043] The following describes a process for advancing the actual timing when the actual timing is later than the reference timing. Figure 4 is a diagram for explaining the process for advancing the actual timing. The vertical and horizontal axes in Figure 4 are the same as those in Figure 3.

[0044] First, the supply control unit 222 determines whether a contact shock has occurred based on the change in the rotation speed before and after contact between the clutch disc 112 and the flywheel 111. Specifically, the supply control unit 222 determines that a contact shock has occurred when the difference in rotation speed between a first rotation speed of the flywheel 111 in the disengaged state and a second rotation speed of the flywheel 111 after the clutch 110 is engaged is equal to or greater than a determination value. The determination threshold is a value used to determine that an impact (contact shock) has occurred at the time of contact, and is determined through experiments or the like. The supply control unit 222 determines that a contact shock has not occurred when the difference in rotation speed is less than the determination value.

[0045] Next, the supply control unit 222 determines whether the timing of the contact shock occurrence is before or after the reference timing. For example, if the rotation speed difference equal to or greater than the determination value is detected at a fourth time point t4 after the second time point t2, the supply control unit 222 determines that the contact shock occurred after the reference timing.

[0046] If a contact shock occurs after the reference timing, the supply control unit 222 increases the second current value A2 when the disengaged clutch 110 is brought into the engaged state. For example, the supply control unit 222 increases the second current value A2 when the disengaged clutch 110 is next brought into the engaged state as the rotational speed difference increases. More specifically, the supply control unit 222 sets the second current value A2 when the disengaged clutch 110 is next brought into the engaged state to a corrected second current value A21 obtained by adding a change amount B of the second current value A2, the change amount B corresponding to the rotational speed difference, to the second current value A2. The change amount B corresponding to the rotational speed difference is determined in advance and stored in the storage unit 210.

[0047] As a result, the amount of hydraulic oil 121 supplied from the third time point t3 to the second time point t2 increases, and the speed of movement of the clutch disc 112 increases. As a result, the time it takes for the clutch disc 112 to contact the flywheel 111 decreases, and the actual timing advances. In other words, the supply control unit 222 can advance the delayed actual timing, making it the reference timing.

[0048] As described above, the supply control unit 222 increases the second current value A2 as the rotation speed difference increases. However, if an excessively large change amount B is added to the second current value A2, the actual timing may become too early.

[0049] Therefore, if the change amount B is too large, the supply control unit 222 increases the second current value A2 in multiple steps. For example, if the change amount B according to the rotation speed difference is equal to or greater than a predetermined current value, the supply control unit 222 increases the second current value by a correction amount C smaller than the change amount B. Specifically, if the change amount B according to the rotation speed difference is equal to or greater than a predetermined current value, the supply control unit 222 changes the second current value by a correction amount C smaller than the change amount B. More specifically, the supply control unit 222 adds the correction amount C to the current second current value A2 to obtain an intermediate corrected current value A22. The correction amount C is, for example, half the change amount B, but is not limited to this. The correction amount C may be the minimum amount by which the current can be changed, or may be a multiple of the minimum value.

[0050] The supply control unit 222 determines whether the rotation speed difference when the clutch 110 in the disengaged state is brought into the engaged state after updating the second current value A2 to an intermediate corrected current value A22 obtained by adding a correction amount to the current second current value A2 is equal to or greater than a determination value. If the rotation speed difference after the current value update is equal to or greater than the determination value, the supply control unit 222 sets the current value of the current to a corrected second current value A21 obtained by adding a correction amount to the intermediate corrected current value A22.

[0051] If the rotation speed difference after updating the current value is less than the determination value, the supply control unit 222 maintains the current value at the intermediate corrected current value A22. In this way, by increasing the second current value A2 in multiple increments, the supply control unit 222 can prevent the actual timing from being set too early.

[0052] The above describes the process of advancing the actual timing when the actual timing is later than the reference timing. Next, the process of delaying the actual timing when the actual timing is earlier than the reference timing will be described. Figure 5 is a diagram for explaining the process of delaying the actual timing. The vertical and horizontal axes in Figure 5 are the same as those in Figure 3.

[0053] If a contact shock occurs before the reference timing, supply control unit 222 reduces second current value A2 when clutch 110 in the disengaged state is engaged. Specifically, if fifth time point t5 at which a rotation speed difference equal to or greater than the determination value is detected is before the reference timing, supply control unit 222 reduces the second current value when clutch 110 in the disengaged state is next engaged. More specifically, supply control unit 222 sets second current value A2 to corrected second current value A23 obtained by subtracting an amount of change corresponding to the difference between the reference timing (second time point t2) and fifth time point t5 from the current second current value A2.

[0054] By doing so, the amount of hydraulic oil 121 supplied from the third time point t3 to the second time point t2 is reduced, slowing down the movement speed of the clutch disc 112. As a result, the time it takes for the clutch disc 112 to contact the flywheel 111 is lengthened, delaying the actual timing. In other words, the supply control unit 222 can delay the earlier actual timing to the reference timing.

[0055] If the change amount corresponding to the difference between the second time point t2 and the fifth time point t5 is equal to or greater than a predetermined current value, the supply control unit 222 may decrease the second current value A2 by a correction amount that is smaller than the change amount. If the change amount is equal to or greater than the predetermined current value, the supply control unit 222 sets the current value of the current to a corrected second current value obtained by subtracting the correction amount from the current second current value A2. This allows the supply control unit 222 to prevent the actual timing at which the clutch disc 112 contacts the flywheel 111 from being excessively delayed.

[0056] As described above, when the actual timing does not match the reference timing, the supply control unit 222 can change the second current value A2 to make the actual timing the reference timing. However, in an actual vehicle, after a contact shock occurs, the contact shock may no longer occur due to deterioration of the clutch 110 over time or changes in the environment. In other words, after a rotation speed difference equal to or greater than the determination value is detected, the rotation speed difference may fall below the determination value when the disengaged clutch 110 is brought into the engaged state. In this case, if the supply control unit 222 changes the second current value A2, the reference timing and the actual timing will no longer match.

[0057] Therefore, the supply control unit 222 changes the second current value A2 when there is a high probability that the reference timing and the actual timing do not match. For example, when a rotation speed difference equal to or greater than the determination value is detected a determination number of times or more, the supply control unit 222 determines that there is a high probability that the reference timing and the actual timing do not match, and changes the second current value A2. Specifically, the supply control unit 222 counts the number of times that a rotation speed difference equal to or greater than the determination value is detected, and when the number of times equals or exceeds the determination number, determines that there is a high probability that the reference timing and the actual timing do not match. While the number of times is less than the determination number, the supply control unit 222 determines that there is a low probability that the reference timing and the actual timing do not match. The determination number is a value used to determine whether to change the second current value. The determination number may be determined appropriately through experiments, etc. A specific value of the determination number is, for example, three, but is not limited to this.

[0058] When a rotation speed difference equal to or greater than the determination value is detected three times, the supply control unit 222 changes the second current value A2 and sets the number of times to 0. This allows the supply control unit 222 to refrain from changing the second current value A2 when the probability that the reference timing and the actual timing do not match is low, and to change the second current value A2 when the probability is high.

[0059] However, the actual timing may become earlier or later than the reference timing due to aging of the clutch 110, changes in the environment, and so on. Therefore, it is conceivable that the actual timing may become later than the reference timing, and then become earlier than the reference timing. In this case, if the number of times that a rotation speed difference equal to or greater than the determination value is detected is counted, there is a risk that the actual timing may be made even earlier than the reference timing, even though it is actually earlier than the reference timing.

[0060] Therefore, the supply control unit 222 counts the number of times a rotation speed difference equal to or greater than the determination value is detected depending on whether the time point is before or after the reference time. For example, the supply control unit 222 counts the first number of times the actual timing is earlier than the reference time. Specifically, the supply control unit 222 counts the first number of times a rotation speed difference equal to or greater than the determination value is detected at a time point before the reference time.

[0061] If the actual timing is later than the reference timing before the first count becomes equal to or greater than the determination count, the supply control unit 222 sets the first count to 0 and counts the second number of times that the actual timing is later than the reference timing. Specifically, if a rotation speed difference equal to or greater than the determination value is detected at least once at a time point after the reference timing before the first count becomes equal to or greater than the determination count, the supply control unit 222 sets the first count to 0 and the second count to 1. Similarly, if a rotation speed difference equal to or greater than the determination value is detected at a time point before the reference timing before the second count becomes equal to or greater than the determination count, the supply control unit 222 sets the second count to 0 and the first count to 1. In this manner, the supply control unit 222 can appropriately change the second current value A2 even when the actual timing becomes earlier or later than the reference timing due to, for example, deterioration of the clutch 110 over time or a change in the environment.

[0062] (Variation 1) When supply control unit 222 reduces the current value over time so that the current value becomes third current value A3, it may reduce the current value continuously or in steps. When reducing the current in steps, supply control unit 222 may reduce the current value at the same rate per unit time or may vary the rate at which the current is reduced per unit time.

[0063] (Variation 2) In the above embodiment, the clutch 110 is a dry clutch in which the flywheel 111 and the clutch disc 112 are in direct contact. However, the clutch 110 is not limited to this. For example, the clutch 110 may be a wet multi-plate clutch in which multiple separate plates connected to the shaft on the flywheel side are connected to multiple friction plates connected to the input shaft. In this case, the multiple friction plates correspond to the clutch disc 112, and the clutch 110 is engaged when the separate plates and the friction plates come into contact with each other.

[0064] [Effects of Clutch System S] As described above, clutch system S includes clutch 110, which is brought into an engaged state by clutch disc 112 moving toward flywheel 111 at a speed corresponding to the amount of hydraulic oil 121 supplied, control valve 120, which supplies hydraulic oil 121 to clutch 110 in an amount corresponding to the current value of current supplied from power source 130, and supply control unit 222, which causes power source 130 to supply current to control valve 120. When clutch 110 is brought into an engaged state from a disengaged state in which clutch disc 112 and flywheel 111 are not in contact, supply control unit 222 causes control valve 120 to supply current of first current value A1, and then changes the current value of the current to be supplied to control valve 120 to second current value A2, which is smaller than first current value A1, and then decreases the current value of the current over time so that the current value reaches third current value A3, which is smaller than second current value A2, at reference timing (second time point t2) when clutch 110 is brought into an engaged state from a disengaged state.

[0065] In this way, the clutch system S can make the clutch disc 112 contact the flywheel 111 at a speed slower than when the clutch disc 112 contacts the flywheel 111 with the first current value A1 supplied to the control valve 120. As a result, the clutch system S can reduce shock when the clutch 110 enters a contact state. Furthermore, the clutch system S can supply a larger amount of hydraulic oil 121 to the clutch 110 than when the current value is immediately changed from the first current value A1 to the third current value A3, thereby shortening the time it takes for the clutch 110 to switch from a disengaged state to an engaged state. In this way, the clutch system S can reduce shock when the clutch 110 enters a disengaged state and shorten the time it takes to switch from a disengaged state to an engaged state. In other words, the clutch system S can appropriately switch the clutch from a disengaged state to an engaged state.

[0066] The present invention has been described above using embodiments, but the technical scope of the present invention is not limited to the scope described in the above embodiments, and various modifications and changes are possible within the scope of the gist of the present invention. For example, all or part of the device can be configured by functionally or physically distributing or integrating any unit. Furthermore, new embodiments resulting from any combination of multiple embodiments are also included in the embodiments of the present invention. The effects of the new embodiments resulting from the combination also have the effects of the original embodiments. [Explanation of symbols]

[0067] S clutch system 100 Power section 101 Output shaft 110 Clutch 111 Flywheel 112 Clutch disc 120 Control valve 121 Hydraulic oil 130 Power supply 140 Pump 150 sensors 200 Supply control device 210 Storage section 220 Control Unit 221 Acquisition Department 222 Supply control section

Claims

1. a clutch having a clutch disc that is movable in the direction of the rotation axis of a flywheel connected to a power unit, and when hydraulic oil is supplied, the clutch disc moves in a direction approaching the flywheel at a speed corresponding to the amount of hydraulic oil, thereby bringing the clutch disc into contact with the flywheel and into an engaged state; a control valve that supplies the hydraulic oil to the clutch in an amount corresponding to the current value of the current supplied from a power source; When the clutch is in a disengaged state where the clutch disc and the flywheel are not in contact with each other, the clutch is brought into the engaged state. supplying the current of a first current value to the control valve; After supplying the current of the first current value to the control valve, the current value of the current to be supplied to the control valve is changed to a second current value that is smaller than the first current value; a supply control unit that reduces the current value of the current over time so that, after setting the current value of the current to the second current value, the current value of the current becomes a third current value that is smaller than the second current value at a timing when the clutch in the disengaged state becomes the engaged state; A clutch system having

2. the timing is a second time point at which a time required for the clutch disc of the clutch in the disengaged state to contact the flywheel has elapsed from a first time point at which the supply of the current of the first current value to the control valve is started.

2. The clutch system of claim 1.

3. the supply control unit reduces the current value of the current by a ratio of a difference between the second current value and the third current value with respect to a time from a third time point at which the current value of the current is set to the second current value to the second time point.

3. The clutch system of claim 2.

4. When the clutch in the disengaged state is switched to the engaged state, if a difference in rotation speed between the flywheel in the disengaged state and the flywheel after the clutch is switched to the engaged state is equal to or greater than a determination value for determining that an impact has occurred at the time of contact, the supply control unit changes the second current value when the clutch is next switched from the disengaged state to the engaged state.

2. The clutch system of claim 1.

5. When the rotation speed difference is detected to be equal to or greater than the determination value, the supply control unit increases the change amount of the second current value as the rotation speed difference increases.

5. The clutch system of claim 4.

6. when a change amount of the second current value according to the rotation speed difference is equal to or greater than a predetermined current value, the supply control unit changes the second current value by a correction amount smaller than the change amount.

6. The clutch system of claim 5.

7. The supply control unit If the rotation speed difference equal to or greater than the determination value is detected before the timing, the second current value is reduced when the clutch is next changed from the disengaged state to the engaged state. If the rotation speed difference equal to or greater than the determination value is detected after the timing, the second current value is increased when the clutch is next changed from the disengaged state to the engaged state. A clutch system according to any one of claims 4 to 6.

8. the supply control unit changes the second current value when the number of times the rotation speed difference equal to or greater than the determination value is detected is equal to or greater than a determination number for determining whether to change the second current value. A clutch system according to any one of claims 4 to 6.

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