Clutch system

Abstract

A clutch system (S) is provided with: a clutch (110) in which a clutch disc (112) and a flywheel (111) are in contact with each other; a control valve (120) for supplying the hydraulic oil (121) to the clutch (110); and a supply control section (222) that supplies electric power from the power source (130) to the control valve (120). The supply control section (222) supplies a current at a first current value (A1) to the control valve (120), then sets the current value of the current to a second current value (A2) that is smaller than the first current value (A1), and after setting the current value to the second current value (A2), decreases the current value over time so that the current value is reduced over time at a timing when the clutch (110) in the disengaged state enters the engaged state. The current value reaches a third current value (A3) that is less than the second current value (A2).

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a clutch system for connecting or disconnecting power transmission. BACKGROUND

[0002] A clutch for connecting or disconnecting power transmission is known. Japanese Unexamined Patent Application Publication No. 2010-241244 discloses a technique of bringing a hydraulically operated clutch from a disengaged state to an engaged state by supplying hydraulic oil to the clutch. SUMMARY

[0003] Problem to be Solved by the Invention

[0004] A clutch disc of a hydraulically operated clutch moves at a speed corresponding to a hydraulic pressure of hydraulic oil supplied to the clutch. Therefore, if the hydraulic pressure of the hydraulic oil supplied to the clutch is high when the clutch disc connected to an input shaft contacts a plate of a flywheel, the clutch disc contacts the plate at a higher speed, and therefore an impact generated when the clutch disc contacts the plate becomes significant. On the other hand, when the hydraulic pressure of the hydraulic oil supplied to the clutch is low, the moving speed of the clutch disc decreases, and therefore the time until the clutch disc contacts the plate of the flywheel becomes long.

[0005] The present disclosure focuses on this point, and an object of the present disclosure is to appropriately bring a clutch from a disengaged state to an engaged state.

[0006] Means for Solving the Problem

[0007] An aspect of the present disclosure provides a clutch system including: a clutch i) including a clutch disc movable in a rotational axis direction of a flywheel connected to a power unit, and ii) brought into an engaged state in which the clutch disc and the flywheel contact each other when the clutch disc moves toward the flywheel at a speed corresponding to an amount of hydraulic oil supplied to the clutch disc; a control valve that supplies the clutch with the hydraulic oil in an amount corresponding to a current value of a current supplied from a power source; and a supply control portion that, when the clutch is converted from a disengaged state in which the clutch disc and the flywheel do not contact each other to the engaged state, i) supplies the control valve with the current at a first current value, ii) sets the current value of the current supplied to the control valve to a second current value smaller than the first current value after supplying the control valve with the current at the first current value, and iii) decreases the current value of the current over time after setting the current value of the current to the second current value, so that the current value of the current reaches a third current value smaller than the second current value at a time when the clutch in the disengaged state is brought into the engaged state.

[0008] The timing can be a second time point that occurs after a lapse of time from a first time point when the supply of the electric current at the first current value to the control valve is started until the clutch disc of the clutch in the disengaged state comes into contact with the flywheel.

[0009] The supply control portion can decrease the current value of the electric current at a rate corresponding to a difference between the second current value and the third current value divided by time, in a time from a third time point at which the current value of the electric current is set to the second current value to the second time point.

[0010] If a rotational speed difference between a rotational speed of the flywheel in the disengaged state and a rotational speed of the flywheel after the clutch enters the engaged state is equal to or greater than a predetermined threshold value for determining that an impact occurs at the time of contact, the supply control portion can modify the second current value for a next transition of the clutch from the disengaged state to the engaged state when the clutch enters the engaged state from the disengaged state.

[0011] The supply control portion can increase the amount of modification of the second current value as the rotational speed difference increases when the rotational speed difference equal to or greater than the predetermined threshold value is detected.

[0012] The supply control portion can modify the second current value by a correction amount smaller than the amount of modification when the amount of modification of the second current value according to the rotational speed difference is equal to or greater than a predetermined current value.

[0013] The supply control portion i) can decrease the second current value for the next transition of the clutch from the disengaged state to the engaged state when a time point at which the rotational speed difference equal to or greater than the predetermined threshold value is detected is earlier than the timing, and ii) can increase the second current value for the next transition of the clutch from the disengaged state to the engaged state when the time point at which the rotational speed difference equal to or greater than the predetermined threshold value is detected is later than the timing.

[0014] The supply control portion can modify the second current value when a number of times at which the rotational speed difference equal to or greater than the predetermined threshold value is detected is equal to or greater than a predetermined number of times for determining whether to modify the second current value.

[0015] The supply control portion i) can decrease the second current value when a first count obtained when the rotational speed difference equal to or greater than the predetermined threshold value is detected before the timing reaches or exceeds the predetermined number of times, and ii) can increase the second current value when a second count obtained when the rotational speed difference equal to or greater than the predetermined threshold value is detected after the timing reaches or exceeds the predetermined number of times.

[0016] The supply control part i) can reset the first count to zero and set the second count to one if the rotational speed difference equal to or greater than the predetermined threshold is detected after the time point and before the first count reaches or exceeds the predetermined number of times, and ii) can reset the second count to zero and set the first count to one if the rotational speed difference equal to or greater than the predetermined threshold is detected before the time point and before the second count reaches or exceeds the predetermined number of times.

[0017] Effects of the Invention

[0018] According to the present disclosure, it is possible to bring the clutch from the disengaged state to the engaged state. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 A configuration of a clutch system is shown.

[0020] Figure 2 A schematic view of a clutch in the engaged state.

[0021] Figure 3 An engagement process is shown.

[0022] Figure 4 A process for making the actual time point occur earlier is shown.

[0023] Figure 5 A process for making the actual time point occur later is shown. DETAILED DESCRIPTION

[0024] [Configuration of Clutch System S]

[0025] Figure 1 A configuration of a clutch system S is shown. The clutch system S is a system that connects or disconnects power transmission between a power unit 100 and a power transmission member. For example, the clutch system S is installed on 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.

[0026] The power unit 100 supplies power to a vehicle equipped with the clutch system S. For example, the power unit 100 is an engine, but can also be a motor.

[0027] The clutch 110 connects or disconnects power transmission between a power transmission member (not shown in the drawings) and the power unit 100. For example, the power transmission member is a transmission mechanism. The transmission mechanism transmits power from the power unit 100 to the wheels of the vehicle while changing the torque and rotational speed. The clutch 110 includes a flywheel 111 and a clutch disc 112. As shown in Figure 1 the state in which the flywheel 111 and the clutch disc 112 do not contact is defined as the disengaged state of the clutch 110.

[0028] The flywheel 111 is coupled to the output shaft 101 of the power unit 100. The flywheel 111 rotates together with the rotation of the output shaft 101 of the power unit 100.

[0029] The clutch disc 112 is in contact with the flywheel 111 to transmit power from the power unit 100 to the power transmission member. When supplied with the hydraulic oil 121, the clutch disc 112 moves toward the flywheel 111 in the rotational axis direction of the flywheel 111. The rotational axis direction is parallel to the axial direction 113 of the output shaft 101. The clutch disc 112 comes into contact with the flywheel 111 by moving toward the flywheel 111 in the axial direction 113. The state in which the clutch disc 112 and the flywheel 111 are in contact is defined as the engaged state of the clutch 110. Figure 2 is a schematic view of the clutch 110 in the engaged state. In the engaged state of the clutch 110, the clutch disc 112 in contact with the flywheel 111 rotates together with the flywheel 111, thereby transmitting power from the power unit 100 to the power transmission member.

[0030] The control valve 120 adjusts the amount of the hydraulic oil 121 to be supplied to the clutch 110. The control valve 120 supplies the clutch disc 112 of the clutch 110 with the amount of the hydraulic oil 121 corresponding to the current value of the current supplied from the power source 130. When supplied with the hydraulic oil 121, the clutch disc 112 moves at a speed corresponding to the amount of the hydraulic oil 121. Specifically, the clutch disc 112 receives a pressure corresponding to the amount of the supplied hydraulic oil 121, and moves toward the flywheel 111 in the axial direction 113 at a speed corresponding to the received pressure. More specifically, as the amount of the supplied hydraulic oil 121 increases, the clutch disc 112 receives a greater pressure, and thus, as the amount of the supplied hydraulic oil 121 increases, the clutch disc 112 moves faster.

[0031] The power source 130 supplies the control valve 120 with a current. The power source 130 is at least one of a generator or a battery that generates power using the power from the power unit 100, but can also be both, and is not limited thereto.

[0032] The pump 140 supplies the control valve 120 with the hydraulic oil 121 contained in the tank 141. For example, the pump 140 is any one of a centrifugal pump, an axial flow pump, or a gear pump. For example, the pump 140 is driven by the power from the power unit 100, but can also be driven by the electric power from the power source 130. The pump 140 can be any pump capable of supplying the control valve 120 with the hydraulic oil 121.

[0033] The sensor 150 detects the rotational speed of the flywheel 111. For example, the sensor 150 detects the rotational speed of the output shaft 101 connected to the flywheel 111 and the power unit 100 as the rotational speed of the flywheel 111. A known sensor capable of detecting the rotational speed of the output shaft 101 can be used as the sensor 150. The sensor 150 detects the rotational speed of the flywheel 111 at predetermined intervals. For example, the predetermined intervals are 10 milliseconds, but are not limited thereto.

[0034] The supply control device 200 includes a memory 210 and a controller 220. The memory 210 is a storage medium including a read only memory (ROM), a random access memory (RAM), a hard disk, or the like. The memory 210 stores a program executed by the controller 220.

[0035] The controller 220 is a computing resource including a processor such as a central processing unit (CPU). The controller 220 realizes the functions of the acquisition portion 221 and the supply control portion 222 by executing the program stored in the memory 210.

[0036] The acquisition portion 221 acquires the rotational speed of the flywheel 111 detected by the sensor 150. When the clutch 110 is in the disengaged state, the acquisition portion 221 acquires a first rotational speed of the flywheel 111. In other words, the acquisition portion 221 acquires the rotational speed detected when the power from the power unit 100 is not transmitted to the power transmission member as the first rotational speed in the disengaged state. Further, after the clutch 110 enters the engaged state, the acquisition portion 221 acquires a second rotational speed of the flywheel 111. In other words, the acquisition portion 221 acquires the rotational speed detected when the power from the power unit 100 is transmitted to the power transmission member as the second rotational speed after the clutch 110 enters the engaged state.

[0037] The supply control portion 222 causes the power source 130 to supply current to the control valve 120. When the supply control portion 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 toward the flywheel 111. Subsequently, when the clutch disc 112 comes into contact with the flywheel 111, the clutch 110 in the disengaged state enters the engaged state.

[0038] The clutch disc 112 moves at a speed corresponding to the amount of hydraulic oil 121 supplied to the clutch disc 112. As the amount of hydraulic oil 121 supplied to the clutch disc 112 increases, the hydraulic pressure applied to the clutch disc 112 also increases. When the hydraulic pressure applied to the clutch disc 112 is high, the moving speed of the clutch disc 112 increases, and the clutch disc 112 contacts the flywheel 111 at high speed. In this case, the impact generated when the clutch disc 112 contacts the flywheel 111 becomes greater. On the other hand, as the amount of hydraulic oil 121 supplied to the clutch disc 112 decreases, the hydraulic pressure applied to the clutch disc 112 also decreases. When the hydraulic pressure applied to the clutch disc 112 is low, the moving speed of the clutch disc 112 decreases, and thus the impact generated when contacting the flywheel 111 decreases, but the time required for the clutch disc 112 to contact the flywheel 111 becomes longer.

[0039] Therefore, the supply control portion 222 controls the current value of the current output from the power supply 130 so that the clutch 110 in the disengaged state appropriately enters the engaged state. For example, after supplying the current having a relatively high current value to the control valve 120, the supply control portion 222 gradually decreases the current value of the current so that the clutch disc 112 reaches an appropriate speed for contacting the flywheel 111. Therefore, the supply control portion 222 can reduce the impact at the time of contact and shorten the time required for the clutch 110 to enter the engaged state from the disengaged state. The process for causing the clutch 110 to enter the engaged state from the disengaged state will be described below. In the following description, the process for causing the clutch 110 to enter the engaged state from the disengaged state is referred to as an engagement process.

[0040] Figure 3 The engagement process is shown. In Figure 3 the horizontal axis 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. When the supply control portion 222 receives an engagement instruction to cause the clutch 110 to enter the engaged state from the disengaged state, the engagement process starts. The engagement instruction is output, for example, from a control device that controls the running of the vehicle. One example of the control device is a transmission control device that controls the gear of the vehicle by controlling the transmission mechanism, but is not limited thereto.

[0041] The supply control portion 222 sets the current value of the current supplied from the power supply 130 to the control valve 120 to the standby current value A0 until the engagement instruction is received. The standby current value A0 is 10 mA, for example, but is not limited thereto. While the current at the standby current value A0 is supplied, the control valve 120 sets the amount of hydraulic oil 121 supplied to the clutch 110 to zero.

[0042] When the engagement instruction is received, the supply control portion 222 sets the current value of the current supplied from the power source 130 to the control valve 120 to a first current value Al. The first time point tl is a time at which the supply control portion 222 sets the current value of the current to the first current value Al and starts to supply the current at the first current value Al to the control valve 120. The first current value Al is larger than the standby current value Ao. The current value of the first current value Al is determined by the specification of the control valve 120 or determined through experiments. For example, a specific value of the first current value Al is 800 mA, but is not limited thereto. The supply control portion 222 continues to hold the current value of the current supplied from the power source 130 to the control valve 120 at the first current value Al until a first time period 310 elapses from the first time point tl. When the current at the first current value Al is supplied, the control valve 120 supplies the clutch 110 with the hydraulic oil 121 in an amount corresponding to the first current value Al.

[0043] The supply control portion 222 causes the power source 130 to supply the current at the first current value Al to the control valve 120, and then sets the current value of the current to a second current value A2. The second current value A2 is smaller than the first current value Al. For example, the second current value A2 is equal to or smaller than half of the first current value Al. For example, a specific value of the second current value A2 is 300 mA, but is not limited thereto. When the current at the second current value A2 is supplied, the control valve 120 supplies the clutch 110 with the hydraulic oil 121 in an amount corresponding to the second current value A2. The supply control portion 222 sets the current value of the current to the second current value A2 at a third time point t3, which is a point in time at which the first time period 310 elapses from the first time point tl. The first time period 310 is determined in advance through experiments or the like, and is, for example, 60 milliseconds, but is not limited thereto. The third time point t3 is a time at which the supply control portion 222 sets the current value of the current to the second current value A2 and starts to supply the current at the second current value A2 to the control valve 120.

[0044] After the current value of the current is set to the second current value A2, the supply control portion 222 sets the current value of the current to a third current value A3. The third current value A3 is smaller than the second current value A2. Specifically, after the current value of the current is set to the second current value A2, the supply control portion 222 decreases the current value of the current to the third current value A3 over time. The control valve 120 decreases the amount of the hydraulic oil 121 supplied to the clutch 110 in accordance with the decrease in the current value of the supplied current.

[0045] The third current value A3 is a current value at which the magnitude of the impact when the clutch disc 112 contacts the flywheel 111 is equal to or less than a predetermined level. For example, the specific value of the third current value A3 is 90 mA, but is not limited thereto. For example, the magnitude of the impact is defined by the change in the rotational speed of the flywheel 111. Specifically, the magnitude of the impact is defined by the difference between the first rotational speed of the flywheel 111 in the disengaged state and the second rotational speed of the flywheel 111 after the clutch 110 enters the engaged state. That is, the third current value A3 is determined by experiment or the like such that the difference between the first rotational speed and the second rotational speed is equal to or less than the predetermined level.

[0046] The supply control portion 222 decreases the current value of the current over time such that the current value reaches the third current value A3 at a predetermined time after the current is set to the second current value A2. The predetermined time is a reference time at which the clutch 110 in the disengaged state enters the engaged state. Specifically, the reference time is the second time point t2, which occurs after a period of time elapses from the first time point tl until the clutch disc 112 of the clutch 110 in the disengaged state contacts the flywheel 111. The reference time in the present embodiment is determined in accordance with the time required for shifting in the vehicle equipped with the clutch system S. In the present embodiment, the time from the first time point tl to the second time point t2 is 200 msec, but is not limited thereto.

[0047] The supply control portion 222 decreases the current value of the current 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 portion 222 decreases the current value at a rate corresponding to the difference between the second current value A2 and the third current value A3 divided by the second time period 320 within the second time period 320 from the third time point t3 at which the current value is set to the second current value A2 to the second time point t2. The supply control portion 222 determines the rate using the following equation (1).

[0048] Rate = (second current value A2 - third current value A3) / (second time period 320) … (1)

[0049] The rate in the present embodiment is (300 - 90) [mA] / (140) [msec], and is 1.5 [mA / msec], but is not limited thereto.

[0050] In this way, compared to a case in which 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, the supply control portion 222 can supply a larger amount of the hydraulic oil 121 to the control valve 120. As a result, the moving speed of the clutch disc 112 increases, and thus the supply control portion 222 can shorten the time required for the clutch disc 112 to contact the flywheel 111.

[0051] Further, if the current value is set to a third current value A3 at a time close to the second time point t2, there is a risk that the deceleration of the clutch disc 112 will not be completed in time, and the clutch disc 112 can contact the flywheel 111 at a high speed. In contrast, the supply control portion 222 decreases the current value over time, thereby decreasing the moving speed of the clutch disc 112 over time. As a result, the supply control portion 222 can reduce the speed at which the clutch disc 112 contacts the flywheel 111, and thus suppress the generation of an impact.

[0052] When the clutch 110 is in the disengaged state, the clutch disc 112 rotates at the same rotational speed as a wheel connected to the clutch disc 112 via a transmission. On the other hand, when the clutch 110 is in the disengaged state, the flywheel 111 rotates at the same rotational speed as the power unit 100. When the clutch disc 112 contacts the flywheel 111 while the rotational speeds of the clutch disc 112 and the flywheel 111 are different, an impact occurs due to a change in the rotational speed of the flywheel 111. Therefore, the clutch disc 112 and the flywheel 111 are controlled in synchronization so that their rotational speeds match when they contact. For example, the synchronization control is control that adjusts the rotational speed of the flywheel 111 to the rotational speed of the clutch disc 112, assuming that the clutch disc 112 contacts the flywheel 111 at a reference time and rotates at the same speed as the wheel at the reference time.

[0053] However, the moving speed of the clutch disc 112 varies depending on factors such as a change in the viscosity or volume of the hydraulic oil 121 caused by a change in the air temperature, a manufacturing tolerance of the clutch 110, and the like. Therefore, the actual time at which the clutch disc 112 contacts the flywheel 111 can become earlier or later. When the actual time is earlier or later than the reference time, the clutch disc 112 contacts the flywheel 111 in a state in which the rotational speeds of the flywheel 111 and the clutch disc 112 are not synchronized. As a result, when the clutch disc 112 contacts the flywheel 111, the rotational speed of the flywheel 111 changes, resulting in an impact.

[0054] Therefore, when an impact occurs, the supply control portion 222 changes the actual time at which the clutch 110 enters the engaged state by modifying the second current value A2. For example, if the actual time is later than the reference time, the supply control portion 222 increases the second current value A2 to cause the actual time to occur earlier.

[0055] A process for causing the actual time to occur earlier when the actual time is later than the reference time is described below. Figure 4 A process for causing the actual time to occur earlier is shown. Figure 4 The vertical and horizontal axes in Figure 3 The vertical and horizontal axes in

[0056] First, the supply control portion 222 determines whether a contact impact occurs based on a change in the rotational speed of the flywheel 111 before and after the clutch disc 112 comes into contact with the flywheel 111. Specifically, if the difference between the first rotational speed of the flywheel 111 in the disengaged state of the clutch 110 and the second rotational speed of the flywheel 111 after the clutch 110 is shifted to the engaged state is equal to or greater than a predetermined threshold value, the supply control portion 222 determines that a contact impact has occurred. The predetermined threshold value is a value for determining that an impact occurs at the time of contact (contact impact), and is determined through experiments or the like. If the rotational speed difference is less than the predetermined threshold value, the supply control portion 222 determines that no contact impact has occurred.

[0057] Next, the supply control portion 222 determines whether the timing at which the contact impact occurs is before or after the reference timing. For example, when the time point at which the rotational speed difference equal to or greater than the predetermined threshold value is detected is later than the second time point t2, the supply control portion 222 determines that the contact impact occurs after the reference timing. As a specific example, when the rotational speed difference equal to or greater than the predetermined threshold value is detected at a fourth time point t4 after the second time point t2, the supply control portion 222 determines that the contact impact occurs after the reference timing.

[0058] When the contact impact occurs after the reference timing, the supply control portion 222 increases the second current value A2 for shifting the clutch 110 from the disengaged state to the engaged state. For example, the supply control portion 222 increases the second current value A2 for the next shift of the clutch 110 from the disengaged state to the engaged state as the rotational speed difference increases. More specifically, the supply control portion 222 sets the second current value A2 for the next shift of the clutch 110 from the disengaged state to the engaged state to a corrected second current value A21 obtained by adding a modification amount B for the second current value A2 determined in accordance with the rotational speed difference to the second current value A2. It should be noted that the modification amount B increases as the rotational speed difference increases. The modification amount B is determined in advance through experiments or the like, and is stored in the memory 210.

[0059] As a result, the amount of hydraulic oil 121 supplied during the time period from the third time point t3 to the second time point t2 increases, thereby increasing the moving speed of the clutch disc 112. Therefore, the time required for the clutch disc 112 to come into contact with the flywheel 111 is reduced, and the actual timing is brought forward. In other words, the supply control portion 222 can make the delayed actual timing occur earlier, thereby aligning the actual timing at which the clutch 110 enters the engaged state with the reference timing.

[0060] As described above, the supply control portion 222 increases the second current value A2 as the rotational speed difference increases. However, if an excessively large modification amount B is added to the second current value A2, the actual timing can occur before the reference timing.

[0061] Therefore, if the modification amount B is equal to or greater than the predetermined current value, the supply control portion 222 increases the second current value A2 in a plurality of steps. For example, if the modification amount B corresponding to the rotational speed difference is equal to or greater than the predetermined current value, the supply control portion 222 increases the second current value by a correction amount C smaller than the modification amount B. Specifically, if the modification amount B corresponding to the rotational speed difference is equal to or greater than the predetermined current value, the supply control portion 222 modifies the second current value by the correction amount C smaller than the modification amount B. More specifically, the supply control portion 222 sets the second current value to an intermediate correction current value A22 obtained by adding the correction amount C to the current second current value A2. For example, the correction amount C is half of the modification amount B, but is not limited thereto. The correction amount C can be a minimum modification amount applicable to the current, or an integer multiple of the minimum amount.

[0062] After the second current value A2 is updated to the intermediate correction current value A22 by adding the correction amount C to the current second current value A2 and the clutch 110 is switched from the disengaged state to the engaged state, the supply control portion 222 determines whether the rotational speed difference is equal to or greater than the predetermined threshold value. When the rotational speed difference after the current value is updated is equal to or greater than the predetermined threshold value, the supply control portion 222 sets the current value to a modified second current value A21 obtained by adding the correction amount C to the intermediate correction current value A22.

[0063] When the rotational speed difference after the second current value A2 is updated to the intermediate correction current value A22 is smaller than the predetermined threshold value, the supply control portion 222 maintains the second current value A2 at the intermediate correction current value A22. In this way, the supply control portion 222 can suppress the advance of the actual time with respect to the reference time by increasing the second current value A2 in a plurality of steps.

[0064] The process of making the actual time occur later when the actual time occurs earlier than the reference time has been described. Next, the process of making the actual time occur earlier when the actual time occurs later than the reference time will be described. Figure 5 The process for making the actual time occur later is shown. Figure 5 The vertical and horizontal axes in FIG. 10 are the same as those in FIG. 9. Figure 3 The vertical and horizontal axes in FIG. 11 are the same as those in FIG. 10.

[0065] When the contact shock occurs before the reference timing, the supply control portion 222 reduces the second current value A2 for the transition of the clutch 110 from the disengaged state to the engaged state. Specifically, if the fifth time point t5 at which the rotational speed difference equal to or greater than the predetermined threshold is detected occurs earlier than the reference timing, the supply control portion 222 reduces the second current value A2 for the next transition of the clutch 110 from the disengaged state to the engaged state. More specifically, the supply control portion 222 sets the second current value A2 to a corrected second current value A23 obtained by subtracting a correction amount corresponding to the difference between the reference timing (the second time point t2) and the fifth time point t5 from the current second current value A2.

[0066] In this way, the amount of the hydraulic oil 121 supplied between the third time point t3 and the second time point t2 is reduced, thereby reducing the moving speed of the clutch plate 112. Therefore, the time required for the clutch plate 112 to come into contact with the flywheel 111 becomes longer, resulting in a delay of the actual timing at which the clutch 110 is transitioned to the engaged state. In other words, the supply control portion 222 can make the advanced actual timing occur later, thereby aligning the actual timing at which the clutch 110 enters the engaged state with the reference timing.

[0067] If the correction 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 portion 222 can reduce the second current value A2 by a correction amount smaller than the correction amount. If the correction amount is equal to or greater than the predetermined current value, the supply control portion 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. Therefore, the supply control portion 222 can prevent the actual timing at which the clutch plate 112 comes into contact with the flywheel 111 from occurring later than the reference timing.

[0068] As described above, when the actual timing and the reference timing do not match, the supply control portion 222 corrects the second current value A2, thereby aligning the actual timing with the reference timing. However, in an actual vehicle, the contact shock can stop occurring after it initially occurs due to aging of the clutch 110, environmental changes, or the like. In other words, even if the rotational speed difference equal to or greater than the predetermined threshold is detected, the rotational speed difference can fall below the threshold when the clutch 110 in the disengaged state enters the engaged state. In this case, if the supply control portion 222 corrects the second current value A2, the actual timing and the reference timing do not match.

[0069] Therefore, if the possibility that the actual time does not match the reference time is high, the supply control portion 222 modifies the second current value A2. For example, when a difference in rotational speed equal to or greater than a predetermined threshold is detected at least a predetermined number of times, the supply control portion 222 determines that the times can not match and modifies the second current value A2. Specifically, the supply control portion 222 counts the number of times a difference in rotational speed equal to or greater than a predetermined threshold is detected, and when the count reaches or exceeds the predetermined number of times, determines that the actual time can not match the reference time. While the count remains below the predetermined number of times, the supply control portion 222 determines that the probability that the actual time does not match the reference time is low. The predetermined number of times is a value used to determine whether to modify the second current value. The predetermined number of times can be appropriately determined through experiments and the like. For example, the specific value of the predetermined number of times is three, but is not limited thereto.

[0070] The supply control portion 222 counts based on whether the point in time at which a difference in rotational speed equal to or greater than a predetermined threshold is detected is before or after the reference time. For example, the supply control portion 222 obtains a first count corresponding to the number of times the actual time occurs earlier than the reference time. Specifically, when a difference in rotational speed equal to or greater than a predetermined threshold is detected at a point in time before the reference time, the supply control portion 222 obtains the first count. If the first count reaches or exceeds the predetermined number of times, the supply control portion 222 decreases the second current value A2.

[0071] The supply control portion 222 obtains a second count corresponding to the number of times the actual time occurs later than the reference time. When a difference in rotational speed equal to or greater than a predetermined threshold is detected at a point in time after the reference time, the supply control portion 222 obtains the second count. If the second count reaches or exceeds the predetermined number of times, the supply control portion 222 increases the second current value A2.

[0072] When a difference in rotational speed equal to or greater than a predetermined threshold is detected three times, the supply control portion 222 modifies the second current value A2 and resets the number of times to zero. Therefore, when the probability that the actual time does not match the reference time is low, the supply control portion 222 can suppress modification of the second current value A2, and when the probability is high, the supply control portion 222 can modify the second current value A2.

[0073] Further, due to aging of the clutch 110, environmental changes, and the like, the actual time can be earlier or later than the reference time. Therefore, the actual time can become earlier than the reference time after being later than the reference time. In this case, counting only the number of times a difference in rotational speed equal to or greater than a predetermined threshold is detected can cause the actual time to be further advanced even if the actual time is already earlier than the reference time.

[0074] Accordingly, before the first count reaches or exceeds the predetermined number of times, when the actual timing occurs after the reference timing, the supply control portion 222 resets the first count to zero and starts obtaining a second count indicating the number of times the actual timing occurs after the reference timing. Specifically, when after the reference timing and before the first count reaches or exceeds the predetermined number of times, even if a rotational speed difference equal to or greater than the predetermined threshold is detected, the supply control portion 222 resets the first count to zero and sets the second count to one. Similarly, before the reference timing and before the second count reaches or exceeds the predetermined number of times, when a rotational speed difference equal to or greater than the predetermined threshold is detected, the supply control portion 222 resets the second count to zero and sets the first count to one. In this way, even when the actual timing becomes earlier or later than the reference timing due to aging of the clutch 110, environmental changes, or the like, the supply control portion 222 can appropriately modify the second current value A2.

[0075] (Modified Example 1)

[0076] When the current value of the current decreases over time to reach a third current value A3, the supply control portion 222 can continuously or in a stepped manner decrease the current value of the current. In the case of stepped decrease, the supply control portion 222 can decrease the current value of the current at a constant rate per unit time, or change the decrease rate per unit time.

[0077] (Modified Example 2)

[0078] In the above embodiment, the clutch 110 is a dry clutch in which the flywheel 111 and the clutch disc 112 directly contact each other. However, the clutch 110 is not limited thereto. For example, the clutch 110 can be a wet multi-plate clutch in which a plurality of separator plates connected to a shaft of the flywheel engage with a plurality of friction plates connected to an input shaft. In this case, the plurality of friction plates correspond to the clutch disc 112. When the separator plates and the friction plates contact each other, the wet multi-plate clutch enters an engaged state.

[0079] [Effects of Clutch System S]

[0080] As described above, the clutch system S includes: the clutch 110 that enters the engaged state when the clutch plate 112 moves toward the flywheel 111 at a speed corresponding to the amount of the hydraulic oil 121 supplied; the control valve 120 that supplies the clutch 110 with the hydraulic oil 121 in an amount corresponding to a current value of the current supplied from the power source 130; and the supply control portion 222 that causes the power source 130 to supply the control valve 120 with the current. When the clutch 110 is switched from the separated state in which the clutch plate 112 and the flywheel 111 do not contact each other to the engaged state, the supply control portion 222 i) supplies the control valve 120 with the current at the first current value Al, and then ii) sets the current value of the current supplied to the control valve 120 to the second current value A2 that is smaller than the first current value Al, and iii) decreases the current value of the current over time after the current value of the current is set to the second current value A2, so that the current value of the current reaches the third current value A3 that is smaller than the second current value A2 at a reference time (second time point t2) at which the clutch 110 in the separated state enters the engaged state.

[0081] In this way, the clutch system S can cause the clutch plate 112 to contact the flywheel 111 at a lower speed than in a case in which the clutch plate 112 contacts the flywheel 111 at the same time as the control valve 120 is supplied with the first current value Al. As a result, the clutch system S can reduce the impact that occurs when the clutch 110 enters the engaged state. Furthermore, the clutch system S can supply the clutch 110 with a larger amount of the hydraulic oil 121 than in a case in which the current value is immediately changed from the first current value Al to the third current value A3, thereby shortening the time required to cause the clutch 110 to enter the engaged state from the separated state. In this way, the clutch system S can reduce the impact that occurs when the clutch 110 in the separated state enters the engaged state, and shorten the time required to cause the clutch 110 to enter the engaged state from the separated state. That is, the clutch system S can appropriately cause the clutch to enter the engaged state from the separated state.

[0082] The present disclosure is explained on the basis of the example embodiments. The technical scope of the present disclosure is not limited to the scope explained in the above embodiments, and various changes and modifications can be made within the scope of the present disclosure. For example, all or a part of the apparatus can be configured with any unit that is functionally or physically dispersed or integrated. Furthermore, example embodiments resulting from any combination thereof are included in the example embodiments of the present disclosure. Furthermore, the effects of the new example embodiments resulting from the combination also have the effects of the original example embodiments.

[0083] [Symbol Description]

[0084] S: Clutch system

[0085] 100: Power unit

[0086] 101: output shaft

[0087] 110: clutch

[0088] 111: flywheel

[0089] 112: clutch disc

[0090] 120: control valve

[0091] 121: hydraulic oil

[0092] 130: power source

[0093] 140: pump

[0094] 150: sensor

[0095] 200: supply control device

[0096] 210: memory

[0097] 220: controller

[0098] 221: acquisition section

[0099] 222: supply control section

Claims

1. A clutch system, including: The clutch, i) includes a clutch disc movable in the direction of the rotation axis of a flywheel connected to a power unit, and ii) when the clutch disc is moved toward the flywheel at a speed corresponding to the amount of hydraulic oil supplied, the clutch enters an engaged state in which the clutch disc and the flywheel are in contact with each other; A control valve supplies the clutch with an amount of hydraulic oil corresponding to the current value of the current supplied from the power source; as well as In the supply control section, when the clutch transitions from a disengaged state (where the clutch disc and the flywheel are not in contact with each other) to an engaged state, the supply control section i) supplies a current at a first current value to the control valve; ii) after supplying the current at the first current value to the control valve, sets the current value supplied to the control valve to a second current value that is less than the first current value; and iii) after setting the current value to the second current value, decreases the current value over time, such that at the moment when the clutch in the disengaged state enters the engaged state, the current value reaches a third current value that is less than the second current value.

2. The clutch system according to claim 1, wherein, The time point is a second time point, which occurs after a period of time elapsed from the first time point when the current at the first current value is supplied to the control valve until the clutch disc of the clutch in the disengaged state contacts the flywheel.

3. The clutch system according to claim 2, wherein, The supply control section reduces the current value of the current at a rate corresponding to the difference between the second current value and the third current value divided by the time from a third time point when the current value of the current is set to the second current value to the second time point.

4. The clutch system according to any one of claims 1 to 3, wherein, If the speed difference between the flywheel's rotational speed in the disengaged state and the flywheel's rotational speed after the clutch enters the engaged state is equal to or greater than a predetermined threshold for determining when an impact occurs upon contact, then when the clutch enters the engaged state from the disengaged state, the supply control section modifies the second current value for the next transition of the clutch from the disengaged state to the engaged state.

5. The clutch system according to claim 4, wherein, When a speed difference equal to or greater than the predetermined threshold is detected, the supply control section increases the modification amount of the second current value as the speed difference increases.

6. The clutch system according to claim 5, wherein, When the modification amount used for the second current value based on the speed difference is equal to or greater than the predetermined current value, the supply control section modifies the second current value by a correction amount less than the modification amount.

7. The clutch system according to claim 4, wherein, The supply control section i) decreases the second current value for the next transition of the clutch from the disengaged state to the engaged state when the time point at which the speed difference equal to or greater than the predetermined threshold is detected is earlier than the time point, and ii) increases the second current value for the next transition of the clutch from the disengaged state to the engaged state when the time point at which the speed difference equal to or greater than the predetermined threshold is detected is later than the time point.

8. The clutch system according to claim 4, wherein, The supply control section modifies the second current value when the number of times the speed difference equal to or greater than the predetermined threshold is equal to or greater than the predetermined number of times used to determine whether to modify the second current value.

9. The clutch system according to claim 8, wherein, The supply control section i) decreases the second current value when a first count obtained when a speed difference equal to or greater than the predetermined threshold is detected before the time point reaches or exceeds the predetermined number of times, and ii) increases the second current value when a second count obtained when a speed difference equal to or greater than the predetermined threshold is detected after the time point reaches or exceeds the predetermined number of times.

10. The clutch system according to claim 9, wherein, The supply control section i) if it detects a speed difference equal to or greater than the predetermined threshold after the time and before the first count reaches or exceeds the predetermined number of times, resets the first count to zero and sets the second count to one; and ii) if it detects a speed difference equal to or greater than the predetermined threshold before the time and before the second count reaches or exceeds the predetermined number of times, resets the second count to zero and sets the first count to one.

Images