Power transmission device

Abstract

To suppress resonance of a damper mechanism when starting an engine.SOLUTION: A power transmission device has a first damper plate connected to a crankshaft of an engine, and a second damper plate connected to the first damper plate via a spring. The power transmission device has a first cam plate comprising a protrusion which projects toward the second damper plate, and a second cam plate which is attached to a rotor connected to an electric motor, and faces the first cam plate. The power transmission device has a one-way clutch which is fitted between the second damper plate or the first cam plate and the rotor, and transmits power to the rotor from the crankshaft.SELECTED DRAWING: Figure 9A

Description

Technical Field

[0001] The present disclosure relates to a power transmission device.

Background Art

[0002] Hybrid vehicles have a power unit consisting of an engine and an electric motor. Further, a damper mechanism is connected to the crankshaft of the engine in order to suppress the transmission of torsional vibrations generated from the crankshaft (see Patent Documents 1-3).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, since an electric motor is incorporated in the power unit, the crankshaft may be started and rotated using this electric motor. However, since a damper mechanism is provided between the electric motor and the crankshaft, there is a risk of resonating the damper mechanism when starting the engine with the electric motor. Since the resonance of this damper mechanism is a factor that increases the vibration and noise of the power unit, it is required to suppress the resonance of the damper mechanism at the time of engine start.

Means for Solving the Problems

[0005] According to the present disclosure, the power transmission device includes a first damper plate connected to the crankshaft of the engine, and a second damper plate connected to the first damper plate via a spring and rotatable relative to the first damper plate. The power transmission device includes a first cam plate movably connected to the second damper plate in the axial direction and having a convex portion protruding toward the second damper plate. The power transmission device includes a second cam plate having a second cam surface facing the first cam surface of the first cam plate, being rotatable relative to the first cam plate, and being attached to a rotating body connected to an electric motor. The power transmission device includes a one-way clutch attached between the second damper plate or the first cam plate and the rotating body for transmitting power from the crankshaft to the rotating body. When power is transmitted from the rotating body toward the crankshaft, due to the relative rotation between the first cam plate and the second cam plate, the convex portion of the first cam plate moves toward the second damper plate, and the convex portion of the first cam plate restricts the relative rotation between the first damper plate and the second damper plate.

Advantages of the Invention

[0006] According to the present disclosure, resonance of the damper mechanism during engine startup can be suppressed.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7A

Figure 7B

Figure 8

Figure 9A

Figure 9B

Figure 10

Figure 11

Figure 12

Figure 13

Mode for Carrying Out the Invention

[0008] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the following description, the same or substantially the same configurations and elements are denoted by the same reference numerals, and repeated descriptions thereof are omitted.

[0009] <First Embodiment> <Power Unit> FIG. 1 is a diagram showing an example of a vehicle 12 including a power unit 11 in which a power transmission device 10 according to an embodiment of the present disclosure is incorporated. As shown in FIG. 1, the vehicle 12 has a power unit 11 including an engine 13 and motor generators MG1 and MG2. A rear-wheel output shaft 14 of the power unit 11 is connected to a rear wheel 17 via a propeller shaft 15 and a rear differential mechanism 16. The power unit 11 also includes a front differential mechanism 18, and the front differential mechanism 18 is connected to a front wheel 19. The illustrated power unit 11 is a power unit for all-wheel drive, but is not limited thereto, and may be a power unit for front-wheel drive or rear-wheel drive.

[0010] FIG. 2 is a diagram showing an example of the internal structure of the power unit 11. As shown in FIG. 2, the power unit 11 has a main output shaft 20 passing through the center of the motor generator MG2 in order to output engine power and motor power to the front and rear wheels 17 and 19. The main output shaft 20 is connected to a front-wheel output shaft 22 via a gear train 21 and is also connected to a rear-wheel output shaft 14 via a transfer clutch 23. The main output shaft 20 is also connected to a power split mechanism 25 including a planetary gear train via a gear train 24. The power split mechanism 25 is connected to the motor generator MG1 and is also connected to the engine 13 via a gear train 26 and a torque converter 27. Further, the main output shaft 20 is connected to the motor generator MG2 via a planetary gear train 28. The front-wheel output shaft 22 is connected to the front differential mechanism 18 described above.

[0011] <Torque Converter> FIG. 3 is a diagram showing a configuration example of the torque converter 27 and its vicinity. As shown in FIG. 3, the crankshaft 30 of the engine 13 is connected to the pump shell 32 via the drive plate 31. Further, the torque converter 27 includes a pump impeller 33 fixed to the pump shell 32 and a turbine runner 34 facing the pump impeller 33. A turbine hub 35 is connected to the turbine runner 34, and a turbine shaft 36 is connected to the turbine hub 35. In a state where the lock-up clutch 40 described later is released, engine power is transmitted from the pump impeller 33 to the turbine runner 34 via the hydraulic oil.

[0012] Further, the torque converter 27 has a lock-up clutch 40 and a lock-up damper 41 that constitute the power transmission device 10. That is, between the engine 13 and the motor generator (electric motor) MG1, a lock-up clutch 40 and a lock-up damper 41 that constitute the power transmission device 10 are provided.

[0013] <Lock-up clutch> The torque converter 27 has a lock-up clutch 40 that directly connects the crankshaft 30 and the turbine shaft 36. The lock-up clutch 40 has a lock-up piston 42 housed in the pump shell 32. The lock-up piston 42 faces the front cover 43 of the pump shell 32 and is slidably supported by the turbine hub 35. With the lock-up piston 42 provided in the pump shell 32 as a boundary, an apply chamber 44 and a release chamber 45 are partitioned in the pump shell 32.

[0014] When engaging the lock-up clutch 40, by controlling the valve body 92 described later, hydraulic oil is supplied to the apply chamber 44 and discharged from the release chamber 45. As a result, the lock-up piston 42 is pressed against the front cover 43, and the lock-up clutch 40 is controlled to the engaged state. On the other hand, when releasing the lock-up clutch 40, by controlling the valve body 92, hydraulic oil is supplied to the release chamber 45 and discharged from the apply chamber 44. As a result, the lock-up piston 42 moves away from the front cover 43, and the lock-up clutch 40 is controlled to the released state.

[0015] <lock-up damper> The torque converter 27 has a lock-up damper 41 through which power is transmitted when the lock-up clutch is engaged. Here, FIG. 4 is a view showing the lock-up damper 41 along the line IV-IV of FIG. 3. As shown in FIGS. 3 and 4, the lock-up damper 41 has an annular outer plate (first damper plate) 51 connected to the lock-up piston 42. A plurality of groove portions 51a are formed on the outer peripheral portion of the outer plate 51, and a plurality of claw portions 42a are formed on the outer peripheral portion of the lock-up piston 42. The claw portions 42a of the lock-up piston 42 are received in the groove portions 51a of the outer plate 51, and the lock-up piston 42 is connected to the outer plate 51 so as to be axially movable relative thereto.

[0016] The lock-up damper 41 has an inner plate (second damper plate) 52 disposed inside the outer plate 51. The lock-up damper 41 also has a plurality of coil springs (springs) 53, 54 disposed in the circumferential direction. One end of each of the coil springs 53, 54 contacts an inner projection 55 of the outer plate 51, and the other end of each of the coil springs 53, 54 contacts an outer projection 56 of the inner plate 52. That is, the coil springs 53, 54 are disposed between the inner projection 55 of the outer plate 51 and the outer projection 56 of the inner plate 52. In other words, the inner plate 52 is connected to the outer plate 51 via the coil springs 53, 54.

[0017] As shown in FIG. 3, the lock-up damper 41 has a driven cam plate (first cam plate) 61 connected to the turbine hub (rotating body) 35 via a one-way clutch 60, and a drive cam plate (second cam plate) 62 connected to the turbine hub 35. The driven cam plate 61 has a cam surface (first cam surface) 63 provided with a cam groove 63a, and the drive cam plate 62 has a cam surface (second cam surface) 64 provided with a cam groove 64a. The cam surface 63 of the driven cam plate 61 and the cam surface 64 of the drive cam plate 62 face each other, and ball members 65 are accommodated in the cam grooves 63a, 64a of the cam surfaces 63, 64.

[0018] The turbine hub 35 and the one-way clutch 60 are spline-coupled, and the one-way clutch 60 transmits power from the driven cam plate 61 toward the turbine hub 35. That is, the one-way clutch 60 transmits power from the crankshaft 30, through the driven cam plate 61, toward the turbine hub 35, while cutting off the power from the turbine hub 35, through the driven cam plate 61, toward the crankshaft 30. Also, the turbine hub 35 and the one-way clutch 60 are spline-coupled, and the one-way clutch 60 is axially movable relative to the turbine hub 35. That is, the driven cam plate 61 held by the one-way clutch 60 is supported by the turbine hub 35 so as to be axially movable.

[0019] A pin member 67 is inserted into the through hole 66 of the inner plate 52, and this pin member 67 is fixed to the driven cam plate 61. That is, the driven cam plate 61 is connected to be integrally rotatable with respect to the inner plate 52 and is also connected to be axially movable with respect to the inner plate 52. Further, the driven cam plate 61 has an engaging portion (convex portion) 68 that protrudes toward the coil springs 53 and 54. Furthermore, a return spring 69 that biases the driven cam plate 61 toward the drive cam plate 62 is attached between the driven cam plate 61 and the turbine hub 35.

[0020] <Motor generator> FIG. 5 is a diagram showing an example of a control system 70 that controls the power unit 11. As shown in FIG. 5, the motor generator MG1 has a stator 71 around which a stator coil 71a is wound and a rotor 72 housed inside the stator 71. An inverter 73 is connected to the stator 71, and a battery pack 85 is connected to the inverter 73. Further, in order to control the motor generator MG1 via the inverter 73, a first motor control unit 74 is connected to the inverter 73. The first motor control unit 74 controls the motor torque and the motor speed of the motor generator MG1 by controlling the inverter 73 composed of a plurality of switching elements and the like. Note that the motor generator MG1 can be controlled to be in a power running state in which power running torque is generated and a regenerative state in which regenerative torque is generated, that is, a power generation state.

[0021] The motor generator MG2 has a stator 81 around which a stator coil 81a is wound, and a rotor 82 accommodated inside the stator 81. An inverter 83 is connected to the stator 81, and a battery pack 85 is connected to the inverter 83. Further, a second motor control unit 84 is connected to the inverter 83 to control the motor generator MG2 via the inverter 83. The second motor control unit 84 controls the motor torque and motor speed of the motor generator MG2 by controlling the inverter 83 composed of a plurality of switching elements and the like. Note that the motor generator MG2 can be controlled to a power running state in which power running torque is generated and a regeneration state in which regeneration torque is generated, that is, a power generation state.

[0022] The battery pack 85 has a battery module 86 composed of a plurality of battery cells, a battery control unit 87 that monitors the charge and discharge of the battery module 86, and a battery sensor 88 that detects the charge and discharge current, terminal voltage, and the like. The battery control unit 87 calculates the state of charge (SOC) of the battery module 86 based on the charge and discharge current, terminal voltage, and the like detected by the battery sensor 88. Note that the SOC of the battery module 86 is a ratio indicating the remaining amount of electricity stored in the battery module 86, and is a ratio of the stored electricity amount to the full charge capacity of the battery module 86.

[0023] <Control System> As shown in FIG. 5, the vehicle 12 has a control system 70 composed of a plurality of electronic control units to control the power unit 11. As the electronic control units constituting the control system 70, in addition to the aforementioned first motor control unit 74, second motor control unit 84, and battery control unit 87, there are a transmission control unit 90 and an engine control unit 91. The transmission control unit 90 is an electronic control unit that controls the torque converter 27, transfer clutch 23, etc. by outputting a control signal to the valve body 92 for hydraulic control. Further, the engine control unit 91 is an electronic control unit that outputs control signals to the throttle valve 93, injector 94, ignition device 95, etc.

[0024] Also, as an electronic control unit constituting the control system 70, there is a vehicle control unit 96 that outputs control signals to the aforementioned control units 74, 84, 87, 90, 91. These control units 74, 84, 87, 90, 91, 96 are communicably connected to each other via an in-vehicle network 97 such as a CAN (Controller Area Network). The vehicle control unit 96 sets the operation target of the power unit 11 based on input information from various control units and various sensors described later. Further, the vehicle control unit 96 generates control signals corresponding to the operation target of the power unit 11, and outputs these control signals to the motor control units 74, 84, the engine control unit 91, the transmission control unit 90, etc.

[0025] As sensors connected to the vehicle control unit 96, there is an accelerator sensor 100 that detects the operation status of the accelerator pedal, and a brake sensor 101 that detects the operation status of the brake pedal. Also, as sensors connected to the vehicle control unit 96, there is a vehicle speed sensor 102 that detects the vehicle speed, which is the traveling speed of the vehicle 12, and an engine rotation sensor 103 that detects the engine rotation speed Ne, which is the rotation speed of the crankshaft 30. Further, a start switch 104 that is operated when the control system 70 is started and stopped is connected to the vehicle control unit 96.

[0026] FIG. 6 is a diagram showing an example of the basic structure of control units 74, 84, 87, 90, 91, 96. As shown in FIG. 6, the control units 74, 84, 87, 90, 91, 96, which are electronic control units, have a microcontroller 112 in which a processor 110, a main memory (memory) 111, etc. are incorporated. A predetermined program is stored in the main memory 111, and the program is executed by the processor 110. The processor 110 and the main memory 111 are connected to be communicable with each other. Note that a plurality of processors 110 may be incorporated in the microcontroller 112, or a plurality of main memories 111 may be incorporated in the microcontroller 112.

[0027] In addition, the control units 74, 84, 87, 90, 91, 96 have an input circuit 113, a drive circuit 114, a communication circuit 115, an external memory 116, a power supply circuit 117, etc. The input circuit 113 converts a signal input from various sensors into a signal that can be input to the microcontroller 112. The drive circuit 114 generates drive signals for various devices such as the inverters 73, 83 and the valve body 92 described above based on the signals output from the microcontroller 112. The communication circuit 115 converts a signal output from the microcontroller 112 into a communication signal directed to another control unit. Also, the communication circuit 115 converts a communication signal received from another control unit into a signal that can be input to the microcontroller 112. Further, the power supply circuit 117 supplies a stable power supply voltage to the microcontroller 112, the input circuit 113, the drive circuit 114, the communication circuit 115, the external memory 116, etc. Programs and various data, etc. are stored in the external memory 116 composed of a non-volatile memory or the like.

[0028] <Operating state of the lockup damper> Next, the operating state of the lock-up damper 41 will be described. As the operating state of the lock-up damper 41, there is a drive state in which engine power is transmitted from the crankshaft 30 to the turbine shaft 36 in order to drive the vehicle 12 by the engine power. Further, as the operating state of the lock-up damper 41, there is a cranking state in which motor power is transmitted from the turbine shaft 36 to the crankshaft 30 in order to start the engine 13 by the motor generator MG1. Note that, as starting conditions for the engine 13 by the motor generator MG1, for example, the SOC of the battery module 86 may fall below a predetermined value, or the required driving force may exceed a predetermined value due to depressing of the accelerator pedal.

[0029] <Drive state> FIG. 7A is a view showing the lock-up damper 41 in the drive state, and FIG. 7B is a view showing the lock-up damper 41 along line VII-VII of FIG. 7A. Further, FIG. 8 is a view showing the lock-up damper 41 in the drive state, and FIG. 8 shows the lock-up damper 41 at the same part as in FIG. 4.

[0030] As shown in FIG. 7A, when engine power is transmitted from the crankshaft 30 toward the turbine shaft 36 with the lock-up clutch 40 engaged, the engine power is transmitted along the arrow FL1. That is, the engine power is transmitted to the turbine shaft 36 through the crankshaft 30, the drive plate 31, the front cover 43, the lock-up piston 42, the outer plate 51, the coil springs 53, 54, the inner plate 52, the driven cam plate 61, the one-way clutch 60, and the turbine hub 35. At this time, since the one-way clutch 60 is in the engaged state, the driven cam plate 61 and the drive cam plate 62 rotate integrally.

[0031] That is, as shown in FIG. 7B, since the rotational speeds V1 and V2 of the driven cam plate 61 and the driving cam plate 62 match each other and the driven cam plate 61 and the driving cam plate 62 do not rotate relative to each other, the driven cam plate 61 is held in a retracted position approaching the driving cam plate 62 by the return spring 69. As a result, the meshing portion 68 of the driven cam plate 61 is separated from the coil springs 53 and 54, so that the coil springs 53 and 54 can freely expand and contract. That is, relative rotation between the outer plate 51 and the inner plate 52 is allowed.

[0032] As described above, since relative rotation between the outer plate 51 and the inner plate 52 is allowed, as shown by the arrow α in FIG. 8, the outer plate 51 advances with respect to the inner plate 52 while expanding and contracting the coil springs 53 and 54. In this way, since the lock-up damper 41 can function properly, transmission of torsional vibration from the crankshaft 30 to the turbine shaft 36 can be suppressed. That is, the quietness of the power unit 11 can be enhanced, and by extension, the quietness of the vehicle 12 can be enhanced.

[0033] <Cranking state> FIG. 9A is a view showing the lock-up damper 41 in the cranking state, and FIG. 9B is a view showing the lock-up damper 41 along the line IX-IX of FIG. 9A. Further, FIG. 10 is a view showing the lock-up damper 41 in the cranking state, and FIG. 10 shows the lock-up damper 41 at the same part as in FIG. 4.

[0034] As shown in FIG. 9A, when transmitting motor power from the turbine shaft 36 toward the crankshaft 30 with the lock-up clutch 40 engaged, the motor power from the motor generator MG1 is transmitted along the arrow FL2. That is, the motor power is transmitted to the crankshaft 30 via the turbine shaft 36, the turbine hub 35, the drive cam plate 62, the driven cam plate 61, the inner plate 52, the coil springs 53 and 54, the outer plate 51, the lock-up piston 42, the front cover 43, and the drive plate 31. At this time, since the one-way clutch 60 is in the released state, the driven cam plate 61 and the drive cam plate 62 rotate relative to each other.

[0035] That is, as shown in FIG. 9B, immediately after the transmission of the motor power, the rotational speed V1 of the drive cam plate 62 exceeds the rotational speed V2 of the driven cam plate 61, and the driven cam plate 61 and the drive cam plate 62 rotate relative to each other. As a result, the driven cam plate 61 moves to a protruding position away from the drive cam plate 62, and the meshing portion 68 of the driven cam plate 61 is inserted between the wire materials 53a and 54a of the coil springs 53 and 54. That is, since the expansion and contraction of the coil springs 53 and 54 are restricted by the meshing portion 68, the relative rotation between the outer plate 51 and the inner plate 52 can be restricted.

[0036] As described above, since the relative rotation between the outer plate 51 and the inner plate 52 is restricted, as shown in FIG. 10, the outer plate 51 and the inner plate 52 rotate almost integrally. Thus, when starting the rotation of the crankshaft 30 by the motor generator MG1, the meshing portion 68 can restrict the expansion and contraction of the coil springs 53 and 54, so that resonance of the lock-up damper 41 accompanying the transmission of motor power can be prevented. In this way, since resonance of the lock-up damper 41 can be prevented, quietness at engine start can be enhanced. Moreover, since resonance of the lock-up damper 41 can be prevented, it is not necessary to quickly increase the engine speed so as to quickly pass through the rotation region accompanied by damper resonance, and the degree of freedom of the cranking control by the motor generator MG1 can be increased. Needless to say, even when the relative rotation between the outer plate 51 and the inner plate 52 is restricted by the meshing portion 68, relative rotation between the outer plate 51 and the inner plate 52 is allowed within a range where the lock-up damper 41 does not resonate.

[0037] <Coast control> As shown in FIG. 9A, when transmitting power from the turbine shaft 36 toward the crankshaft 30, the expansion and contraction of the coil springs 53 and 54 are restricted by the meshing portion 68, and the relative rotation between the outer plate 51 and the inner plate 52 is restricted. For this reason, even during coasting when the depression of the accelerator pedal is released while the vehicle is running, since power is transmitted from the turbine shaft 36 toward the crankshaft 30, there is a risk that the expansion and contraction of the coil springs 53 and 54 are restricted to generate a shock. Therefore, a control system 70 that forms part of the power transmission device 10 executes coast control for suppressing shock during coasting.

[0038] FIG. 11 is a flowchart showing an example of the execution procedure of coast control. Each step of the coast control shown in FIG. 11 is a step executed by the processor 110 constituting the control system 70. Further, the coast control shown in FIG. 11 is control that is executed by the control system 70 at a predetermined cycle after the control system 70 is activated by a start switch operation.

[0039] As shown in FIG. 11, the control system 70 proceeds to step S10 and determines whether the engine is running. If the control system 70 determines in step S10 that the engine is running, it proceeds to step S11 and determines whether the lock-up clutch 40 is engaged. Note that the lock-up clutch 40 is switched to the engaged state when the vehicle speed exceeds a predetermined value and is switched to the released state when the vehicle speed is below the predetermined value.

[0040] If the control system 70 determines in step S11 that the lock-up clutch 40 is engaged, it proceeds to step S12 and determines whether the depression of the accelerator pedal by the driver has been released. Note that the situation where the depression of the accelerator pedal is released in step S12 is a situation where the vehicle 12 shifts to coasting while the lock-up clutch 40 is engaged and power is transmitted from the turbine shaft 36 toward the crankshaft 30. Then, if the control system 70 determines in step S12 that the depression of the accelerator pedal has been released, it proceeds to step S13 and determines whether the engine speed Ne exceeds a predetermined threshold value N1.

[0041] If the control system 70 determines in step S13 that the engine speed Ne exceeds the threshold value N1, it proceeds to step S14 and determines whether the SOC of the battery module 86 is below a predetermined threshold value S1. If the control system 70 determines in step S14 that the SOC is below the threshold value S1, it proceeds to step S15 and executes the power generation control of the motor generator MG1.

[0042] That is, when the engine speed Ne exceeds the threshold value N1, the engine brake during coasting tends to increase, and there is a risk that the drive cam plate 62 and the driven cam plate 61 will rotate relative to each other by more than a predetermined angle. Therefore, the control system 70 controls the motor generator MG1 to be in the power generation state, thereby actively decelerating the turbine shaft 36 by the motor generator MG1. As a result, the relative rotation between the drive cam plate 62 and the driven cam plate 61 can be suppressed, and the engagement of the engaging portion 68 with the coil springs 53, 54 can be prevented. In this way, by preventing the engagement of the engaging portion 68 with the coil springs 53, 54, it is possible to prevent the occurrence of shock when shifting to coasting and effectively absorb the vibration generated by the torque fluctuation of the engine 13 after shifting to coasting.

[0043] Subsequently, the control system 70 proceeds to step S16 and determines whether or not the driver has resumed depressing the accelerator pedal. If the control system 70 determines in step S16 that the accelerator pedal has not been depressed, it returns to step S13 and determines again whether or not the engine speed Ne exceeds the threshold value N1. That is, the power generation state of the motor generator MG1 continues until the vehicle shifts from coasting to engine driving by depressing the accelerator pedal. On the other hand, if the control system 70 determines in step S16 that the accelerator pedal has been depressed, it proceeds to step S17 and executes normal control to control the motor generator MG1 and the like according to the driver's driving operation.

[0044] On the other hand, when the control system 70 determines in step S14 that the SOC is equal to or greater than the threshold value S1, it proceeds to step S18 and controls the lock-up clutch 40 to the released state. That is, the situation where the SOC is equal to or greater than the threshold value S1 means that it is difficult to charge the battery module 86 by the motor generator MG1, and it is difficult to perform power generation control of the motor generator MG1. Therefore, the control system 70 switches and sets the power transmission path so as to bypass the lock-up damper 41 by releasing the lock-up clutch 40. That is, by releasing the lock-up clutch 40, power can be transmitted from the turbine shaft 36 to the crankshaft 30 via the turbine runner 34 and the pump impeller 33, preventing the occurrence of shock when shifting to coasting and effectively absorbing the vibration generated by the torque fluctuation of the engine 13 after shifting to coasting.

[0045] Subsequently, the control system 70 proceeds to step S16 and determines whether or not the driver has resumed depressing the accelerator pedal. When the control system 70 determines in step S16 that the accelerator pedal has not been depressed, it returns to step S13 and determines again whether or not the engine speed Ne exceeds the threshold value N1. That is, the released state of the lock-up clutch 40 continues until the driver depresses the accelerator pedal to shift from coasting to engine operation. On the other hand, when the control system 70 determines in step S16 that the accelerator pedal has been depressed, it proceeds to step S17 and executes normal control for controlling the lock-up clutch 40 and the like according to the driver's driving operation.

[0046] <Second Embodiment> In the example shown in FIG. 2, the lock-up damper 41 that constitutes the power transmission device 10 is incorporated in the torque converter 27, but the present invention is not limited to this. Here, FIG. 12 is a diagram showing an example of a power unit 130 in which a power transmission device 120 according to another embodiment of the present disclosure is incorporated. FIG. 13 is a diagram showing a configuration example of the power transmission device 120 and its vicinity. In FIGS. 12 and 13, the same components and members as those shown in FIGS. 2 and 3 are denoted by the same reference numerals, and their descriptions are omitted.

[0047] As shown in FIG. 12, the engine 13 and the motor generator MG1 are connected to each other via a power transmission device 120, a gear train 26, and a power split mechanism 25. That is, a power transmission device 120 is provided between the engine 13 and the motor generator MG1. As shown in FIG. 13, the power transmission device 120 has an annular outer plate (first damper plate) 121 connected to the crankshaft 30 of the engine 13. The power transmission device 120 also has an inner plate 52 disposed inside the outer plate 121, and a plurality of coil springs 53, 54 disposed between the outer plate 121 and the inner plate 52.

[0048] Further, a damper hub (rotating body) 123 is connected to the gear train 26 via a connecting shaft 122. The power transmission device 120 includes a driven cam plate 61 connected to the damper hub 123 via a one-way clutch 60, and a drive cam plate 62 connected to the damper hub 123. The damper hub 123 and the one-way clutch 60 are spline-coupled, and the one-way clutch 60 transmits power from the driven cam plate 61 toward the damper hub 123. That is, the one-way clutch 60 transmits power from the crankshaft 30 through the driven cam plate 61 toward the damper hub 123, while cutting off the power from the damper hub 123 through the driven cam plate 61 toward the crankshaft 30. Also, the damper hub 123 and the one-way clutch 60 are spline-coupled, and the one-way clutch 60 is axially movable relative to the damper hub 123. That is, the driven cam plate 61 held by the one-way clutch 60 is supported by the damper hub 123 so as to be axially movable.

[0049] Even with such a power transmission device 120, when starting the rotation of the crankshaft 30 by the motor generator MG1 as in the power transmission device 10 described above, the driven cam plate 61 and the drive cam plate 62 can be relatively rotated, and the meshing portion 68 of the driven cam plate 61 can be engaged with the coil springs 53, 54. Thereby, the expansion and contraction of the coil springs 53, 54 can be restricted by the meshing portion 68, and the resonance of the damper mechanism including the coil springs 53, 54 can be prevented. Thus, since the resonance of the damper mechanism can be prevented, the quietness when starting the engine 13 by the motor generator MG1 can be enhanced.

[0050] <Other Embodiments> The present disclosure is not limited to the above-described embodiments, and it goes without saying that various modifications can be made without departing from the gist thereof. For example, in the example shown in FIG. 10, the engaging portion 68 is pressed against all the coil springs 53 and 54, but the present disclosure is not limited thereto, and the engaging portion 68 may be pressed against at least one of the coil springs 53 and 54. Further, in the illustrated example, the one-way clutch 60 is attached to the turbine hub 35 so as to be axially movable, but the present disclosure is not limited thereto, and the driven cam plate 61 may be attached to the one-way clutch 60 so as to be axially movable. Further, in the illustrated example, the one-way clutch 60 is attached to the driven cam plate 61, but the present disclosure is not limited thereto, and the one-way clutch 60 may be attached to the inner plate 52.

[0051] In the illustrated example, the engaging portion 68 inserted between the wire rods 53a and 54a of the coil springs 53 and 54 is provided on the driven cam plate 61, but the present disclosure is not limited thereto, and other-shaped convex portions may be provided on the driven cam plate 61. For example, by inserting the convex portion provided on the driven cam plate 61 into the gap between the outer plate 51 and the inner plate 52, the relative rotation between the outer plate 51 and the inner plate 52 may be directly restricted. Needless to say, even when the relative rotation between the outer plate 51 and the inner plate 52 is restricted by the convex portion, the relative rotation between the outer plate 51 and the inner plate 52 is allowed within a range where damper resonance does not occur. Further, in the above description, the control system 70 is constituted by six control units 74, 84, 87, 90, 91, and 96, but the present disclosure is not limited thereto. For example, the control system 70 may be constituted by one control unit, or may be constituted by two or more control units.

Description of Reference Numerals

[0052] 10…Power transmission device, 13…Engine, 27…Torque converter, 30…Crankshaft, 35…Turbine hub (rotating body), 42…Lock-up piston, 51…Outer plate (first damper plate), 52…Inner plate (second damper plate), 53, 54…Coil spring (spring), 53a, 54a…Wire rod, 60…One-way clutch, 61…Driven cam plate (first cam plate), 62…Driving cam plate (second cam plate), 63…Cam surface (first cam surface), 64…Cam surface (second cam surface), 68…Engaging portion (protrusion), 70…Control system, 110…Processor, 111…Main memory (memory), 120…Power transmission device, 121…Outer plate (first damper plate), 123…Damper hub (rotating body), MG1…Motor generator (electric motor), Ne…Engine speed (rotation speed of crankshaft), N1…Threshold value

Claims

1. A power transmission device provided between an engine and an electric motor, a first damper plate connected to the crankshaft of the engine, a second damper plate connected to the first damper plate via a spring and relatively rotatable with respect to the first damper plate, a first cam plate movably connected to the second damper plate in the axial direction and having a convex portion protruding toward the second damper plate, a second cam plate having a second cam surface facing the first cam surface of the first cam plate, relatively rotatable with respect to the first cam plate, and attached to a rotating body connected to the electric motor, a one-way clutch attached between the second damper plate or the first cam plate and the rotating body for transmitting power from the crankshaft to the rotating body, having, when power is transmitted from the rotating body toward the crankshaft, due to the relative rotation between the first cam plate and the second cam plate, the convex portion of the first cam plate moves toward the second damper plate, and the convex portion of the first cam plate restricts the relative rotation between the first damper plate and the second damper plate, a power transmission device.

2. In the power transmission device according to Claim 1, the convex portion of the first cam plate is inserted between the wires of the spring to restrict the relative rotation between the first damper plate and the second damper plate, a power transmission device.

3. In the power transmission device according to Claim 1, when power is transmitted from the crankshaft toward the rotating body, the first cam plate and the second cam plate rotate integrally, and the relative rotation between the first damper plate and the second damper plate is allowed, a power transmission device.

4. In the power transmission device according to Claim 1, the rotating body is a turbine hub of a torque converter, the first damper plate is connected to a lock-up piston of the torque converter, a power transmission device.

5. In the power transmission device according to Claim 1, comprising a processor and a memory communicably connected to each other, and having a control system for controlling the electric motor, the control system controls the electric motor to be in a power generation state when power is transmitted from the rotating body toward the crankshaft under the condition that the rotational speed of the crankshaft exceeds a threshold value, a power transmission device.

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