JP4642500B2 - Centrifugal clutch device for vehicle - Google Patents

Description

  The present invention relates to a vehicular centrifugal clutch device that performs connection and disconnection between rotating elements on a power source side and a wheel side by centrifugal force generated by rotation of a power source.

  Some vehicles such as motorcycles use a centrifugal clutch device as a power transmission unit. Centrifugal clutches are usually a clutch mechanism that connects and disconnects the power source side and wheel side rotating elements by frictional contact, etc., and a weight that is provided on the power source side rotating element and biases the clutch mechanism to the connection side by centrifugal force. A centrifugal member such as a roller, and spring means for urging the centrifugal member in a direction against the centrifugal force, and when the rotational speed of the rotating element on the power source side exceeds the set speed, the centrifugal member The clutch mechanism is connected against the force of the means.

  In such a centrifugal clutch device, on / off of the clutch mechanism is controlled only by the rotational speed of the rotating element on the power source side. For example, the rotating speed of the rotating element on the power source side is equal to or lower than the set speed during deceleration. If it drops to, the clutch mechanism is automatically turned off, and the connection between the power source and the wheel (drive wheel) side is released.

For this reason, a mechanism for mechanically restricting the return of the centrifugal member when the rotational speed of the rotating element on the wheel side becomes larger than the rotational speed of the rotating element on the power source side during deceleration or the like is provided. A technique for delaying the off operation has been devised (see Patent Document 1).
JP 11-159547 A

However, in this conventional centrifugal clutch device for a vehicle, since the return of the centrifugal member is mechanically regulated according to the rotational speed difference between the rotating elements on the wheel side and the power source side, various operations of the vehicle are performed. It is difficult to precisely control the clutch mechanism according to the situation.
For example, when the vehicle is decelerating, there is a case where the driver wants to obtain the engine braking force until immediately after the throttle is returned and the vehicle stops. In the conventional centrifugal clutch device for a vehicle, the rotation of the rotating element on the power source side Since the clutch mechanism is controlled only by the speed and the rotational difference between the two rotating elements, clutch control according to the vehicle speed cannot be performed.

  Therefore, the present invention is intended to provide a vehicular centrifugal clutch device capable of precisely controlling a clutch mechanism in accordance with a driving situation of the vehicle.

In order to achieve the above object, the invention described in claim 1 is directed to a power source side rotating element (for example, an input drum 1 in an embodiment described later) and a wheel side rotating element (for example, an output in an embodiment described later). A clutch mechanism (for example, a clutch mechanism 30 in an embodiment described later) for connecting and disconnecting between the shafts 2) and a rotating element on the power source side rotate integrally, and the clutch mechanism is moved to the connecting side by centrifugal force. A centrifugal member to be urged (for example, a weight roller 39 in an embodiment to be described later) and a spring means (for example, to be described later) that applies a spring force against the centrifugal force to the centrifugal member and urges the clutch mechanism in the breaking direction. In the centrifugal clutch device for a vehicle provided with the coil spring 41) in the embodiment, an operating force is applied to the clutch mechanism by electrical control in accordance with the driving condition of the vehicle. A clutch assist device (for example, a clutch assist device 50 in an embodiment described later) that converts the operation along the radial direction of the centrifugal member into an operation along the axial direction and transmits an operation force to the clutch mechanism. (For example, a movable cam member 40 and a coil spring 41 in an embodiment described later) are provided, and the clutch assist device is provided on an axially movable portion (for example, the movable cam member 40 in an embodiment described later) of the operation conversion mechanism. Added hydraulic operating force.
In the case of this invention, when the clutch assist device is controlled at the time of electricity according to the driving situation of the vehicle such as the vehicle speed, the basic control of the clutch mechanism according to the rotation speed of the rotating element on the power source side is changed to another driving situation. The corresponding control is applied, and the disengagement state of the clutch mechanism is appropriately adjusted by the clutch assist device.
Specifically, the operation along the radial direction of the centrifugal member is transmitted to the clutch mechanism after being converted into the operation along the axial direction via the operation conversion mechanism, and the operation force by the hydraulic pressure of the clutch assist device is transmitted to the operation conversion mechanism. Is transmitted to the clutch mechanism via the movable portion in the axial direction.
For this reason, for example, when the clutch assist device is electrically controlled according to the vehicle speed, the engine braking force can be applied to the wheel side until the vehicle speed sufficiently decreases during deceleration.

According to a second aspect of the present invention, in the first aspect of the present invention, the clutch assist device includes an electrically controlled valve (for example, an electromagnetic valve 70 in an embodiment described later) that switches hydraulic pressure supply / discharge. It was.
In this case, when the hydraulic pressure supply / discharge is switched by the electrically controlled valve of the clutch assist device, the operating force applied to the clutch mechanism is switched on / off.

  According to the first aspect of the present invention, the operation force applied from the clutch assist device to the clutch mechanism can be electrically controlled in accordance with the driving situation of the vehicle, so that it depends on the rotational speed of the rotating element on the power source side. Therefore, the clutch assist device can be adjusted by the clutch assist device in accordance with the driving situation of the vehicle, while the control for disengaging the clutch mechanism is the basic control. Therefore, according to the present invention, the clutch mechanism can be precisely controlled according to the driving situation of the vehicle.

According to the first aspect of the present invention, since the operation force by the hydraulic pressure of the clutch assist device can be applied to the clutch mechanism via the movable portion in the axial direction of the operation conversion mechanism, it is easy to make compact. Even with the simple structure, the operation of the clutch mechanism can be reliably assisted.

According to the second aspect of the present invention, since the operation force applied to the clutch mechanism from the clutch assist device is controlled by on / off switching of the hydraulic pressure by the electric control type valve, the electric control type valve is simply controlled. The clutch mechanism can be precisely controlled.

An embodiment of the present invention will be described below with reference to FIGS.
In this embodiment, the vehicular centrifugal clutch device according to the present invention is applied to a power transmission unit in a hydrostatic continuously variable transmission of a motorcycle. FIG. 2 shows the overall configuration of the hydrostatic continuously variable transmission. FIG.

First, the hydrostatic continuously variable transmission shown in FIG. 2 will be described.
In FIG. 2, 1 is an input drum which is a rotating element on the power source (engine) side, and 2 is an output shaft which is a rotating element on the wheel side. The input drum 1 is coaxially disposed on the outer peripheral side of the output shaft 2, is supported by the transmission housing 3A via the bearing 4, and is connected to the outer periphery of the input drum 5 on the engine side (not shown) via the input gear 5. Engaged with the drive gear. The output shaft 2 is supported at one end side by the input drum 1 via the bearing 6 and supported at the other end side by the transmission housing 3B via the bearing 7 and has the other end protruding from the transmission housing 3B. It is linked to drive wheels via a gear mechanism (not shown) and a drive shaft.
The transmission housings 3A and 3B are fixed to the engine or the body frame, and the input drum 1 and the output shaft 2 are rotatably supported by these transmission housings 3A and 3B, and free rotation between the two is allowed. Has been.

  A pump cylinder 8 a of the plunger pump 8 and a motor cylinder 9 a of the plunger motor 9 are attached to the outer periphery of the substantially central portion of the output shaft 2. The pump cylinder 8a and the motor cylinder 9a are integrated with the passage block 10 therebetween, and the motor cylinder 9a portion is splined to the output shaft 2. The plunger pump 8 and the plunger motor 9 are both of an axial type, and a plurality of plungers 8c, 9c are accommodated in cylinder holes 8b, 9b annularly arranged in the cylinders 8a, 9a so as to advance and retreat in the axial direction. Yes. The plungers 8c and 9c of the pump 8 and the motor 9 are arranged in opposite directions, and a swash plate 11 is provided at a position facing the plunger 8c on the pump 8 side, and a swash plate is placed on the position facing the plunger 9c on the motor 9 side. 12 is provided.

The swash plate 11 is supported by a bearing 13 disposed obliquely on the inner peripheral surface of the input drum 1, and swings and rotates with the rotation of the input drum 1 while maintaining a constant inclination angle with respect to the output shaft 2. The front surface of the swash plate 11 abuts on the tip of the plunger 8c on the pump 8 side, and causes the plunger 8c to apply a component force in the rotational direction and the axial direction as the input drum 1 rotates.
On the other hand, the swash plate 12 is supported by a swash plate holder 14 having a bearing structure, and the swash plate holder 14 is supported and fixed to the transmission housing 3B via an inclination angle adjusting mechanism 15. The front surface of the swash plate 12 is in contact with the tip of the plunger 9c on the motor 9 side, and a reaction force in the rotational direction and the axial direction is applied to the plunger 9c as the motor cylinder 9a (output shaft 2) rotates.

  The passage block 10 is formed with a radially outer high pressure passage 16 connected in a ring shape and a radially inner low pressure passage 17 having a similar structure. The passage block 10 has a pump side (cylinder hole 8 c) in the discharge stroke of the plunger pump 8 that communicates with the high pressure passage 16 and a pump chamber (cylinder hole 8 c) in the suction stroke communicates with the low pressure passage 17. There is provided a hydraulic pressure distribution mechanism 18 and a motor side hydraulic pressure distribution mechanism 19 that communicates the cylinder hole 9c in the volume expansion stroke of the plunger motor 9 with the high pressure passage 16 and the cylinder hole 9c in the volume reduction stroke with the low pressure passage 17. Yes. A closed circuit is formed between the plunger pump 8 and the plunger motor 9 by the passages 16 and 17 in the passage block 10 and the hydraulic distribution mechanisms 18 and 19, and the closed circuit is filled with hydraulic oil in a substantially sealed state. ing. Accordingly, the hydraulic oil discharged from the plunger pump 8 (cylinder hole 8c in the discharge area) operates the plunger motor 9 through the high-pressure passage 16 by the discharge flow rate, and at the same time, the same amount of hydraulic oil flows from the plunger motor 9 to the low-pressure passage 17. Is returned to the plunger pump 8 (cylinder hole 8c in the suction region). However, the operation of the plunger motor 8 at this time causes the motor cylinder 9a (output shaft 2) itself to rotate by receiving the reaction force of the swash plate 12.

  In this hydrostatic continuously variable transmission, the rotation of the input drum 1 is input to the plunger 8c on the pump 8 side as a component force in the rotational direction and the axial direction via the swash plate 11, and the input is the aforementioned plunger motor. 9 is converted into a hydraulic pressure for actuating 9. The hydraulic reaction force is transmitted to the output shaft 2 as a torque that directly rotates the output shaft 2 (pump cylinder 8a). Therefore, the rotation transmission from the input drum 1 to the output shaft 2 is performed by being divided into a hydraulic transmission path via the plunger motor 9 and a direct mechanical transmission path via the pump cylinder 8a.

  By the way, the plunger 8c on the pump 8 side receives an axial pressing force from the swash plate 11 with the relative rotation of the input drum 1 and the pump cylinder 8a. A corresponding hydraulic fluid flow is produced. At this time, the rotational speed and torque of the plunger motor 9 generated by the flow of hydraulic oil in the closed circuit are determined by the capacity difference between the pump 8 side and the motor 9 side. In this hydrostatic continuously variable transmission, the tilt angle of the swash plate 12 is operated by the tilt angle adjusting mechanism 15 so that the capacity difference between the pump 8 side and the motor 9 side can be adjusted steplessly. ing. In the case of this hydrostatic continuously variable transmission, the transmission gear ratio between the input drum 1 and the output shaft 2 is operated by the tilt angle adjusting mechanism 15 so that the swash plate 12 is orthogonal to the output shaft 2 (the tilt angle is 0). When operated, the gear ratio is maximized (approximately 1: 1).

  The tilt angle adjusting mechanism 15 includes the swash plate holder 14 that holds the swash plate 12, the hemispherical guide surface 20 of the transmission housing 3B that slidably supports the back portion of the swash plate holder 14, and the swash plate. A slide hanger 21 that swingably supports an arm 14a projecting from the upper end of the holder 14, and supports the slide hanger 21 in a screwed state. The slide hanger 21 is moved back and forth in the axial direction by rotating around its own axis. A ball screw 22 to be moved and a servo motor (not shown) that rotates the ball screw 22 forward and backward are provided. The servo motor appropriately rotates the ball screw 22 under the control of a controller (not shown), thereby changing the front / rear position of the slide hanger 21 and thus the swash plate holder 14 and the swash plate 12 to a desired inclination angle. 2 denotes a reduction gear that reduces the rotation of the servo motor and transmits it to the ball screw 22. The controller receives a rotational speed signal of the power source (engine) and other signals indicating the driving state of the vehicle, and controls the output of the servo motor based on these input signals.

  The motor-side hydraulic distribution mechanism 19 in the passage block 10 is closed by shutting off the communication on the motor 9 side with respect to the high-pressure passage 16 and the low-pressure passage 17 when the inclination angle of the swash plate 12 is operated to 0 °. A lockup mechanism 24 is added to stop the flow of hydraulic oil in the circuit. This lock-up mechanism 24 operates a cam ring 26 that controls the operation of a plurality of distribution valves 25 in the motor-side hydraulic distribution mechanism 19 by a hydraulic lock-up actuator 27, and all the supply on the motor 9 side by the distribution valve 25. By simultaneously closing the high-pressure inflow side of the discharge port 28, the flow of hydraulic oil in the closed circuit is stopped. Therefore, when the lockup mechanism 24 is operated in this way, the plunger 8c on the pump 8 side is locked, and the rotation of the input drum 1 is transmitted to the output shaft 2 as it is through the pump cylinder 8a.

  Further, the hydrostatic continuously variable transmission is provided with a clutch mechanism 30 for operating connection and disconnection of power from the input drum 1 to the output shaft 2. This clutch mechanism 30 is a fluid type clutch mechanism, and by bypassing the high pressure passage 16 and the low pressure passage 17, the reaction force of the plunger 8c is made substantially zero, thereby interrupting the power transmission from the swash plate 11. ing.

  As shown in FIGS. 8 and 9, the clutch mechanism 30 includes a bypass passage 31 that directly connects the high-pressure passage 16 and the low-pressure passage 17 in the passage block 10 and an operation rod 32 that opens and closes the bypass passage 31. The advance / retreat position of the operation rod 32 is controlled by the rod control unit 33 (see FIG. 2).

  The operation rod 32 is slidably received in a receiving hole 34 formed in the axial center of the output shaft 2 so as to open to one end side, and an annular groove is formed on the outer periphery on the tip side inserted into the receiving hole 34. 35 is formed.

  The bypass passage 31 has a first passage 36 formed across the pump cylinder 8 a and the output shaft 2 so as to communicate the high pressure passage 16 and the receiving hole 34, and an output shaft so as to communicate the receiving hole 34 and the low pressure passage 17. 2 and the second passage 37 formed across the passage block 10, and the annular groove 35 of the operating rod 32 connecting the first passage 36 and the second passage 37 in the receiving hole 34. The annular groove 35 is offset from the opening of the first passage 36 in the receiving hole 34 when the operating rod 32 enters the bottom of the receiving hole 34 as shown in FIG. When the operation rod 32 is at a position retracted by a predetermined amount from the maximum approach position as shown in FIGS. 1 and 8, the first passage 36 and the second passage 37 are connected. It is like that. The bypass passage 31 is switched between cutoff and communication by switching the two positions of the operating rod 32 in the axial direction. When the operating rod 32 is in an intermediate region between the two positions, the bypass passage 31 is provided with the first passage 36 according to the position of the rod. The opening area (the flow area of the bypass passage 31) is adjusted. Therefore, at this time, the flow rate of the hydraulic oil passing through the bypass passage 31 is adjusted according to the displacement of the operation rod 32, and as a result, the flow rate of the hydraulic oil supplied to the plunger motor 9 side is adjusted. Therefore, the operation rod 32 can smoothly connect and disconnect the power between the input drum 1 and the output shaft 2 through the half-clutch state by an axial operation by the rod control unit 33.

  Further, as shown in FIG. 2, the rod control unit 33 includes a bottomed cylindrical control unit case 38 that is integrally coupled to the input drum 1 and covers the end portion of the output shaft 2, and the control unit case 38. The weight roller 39 is a centrifugal roller member that is accommodated in a rollable manner along the radial direction, and an inclined wall 40a that is accommodated and supported in the control unit case 38 so as to be axially displaceable and projects radially outward. And a coil spring 41 (spring means) that urges the movable cam member 40 toward the bottom wall of the control unit case 38. The central portion of the movable cam member 40 is an output shaft. 2 is connected to the base end portion of the operation rod 32 protruding from 2.

The movable cam member 40 has a cylindrical wall 40b protruding from the center of the inclined wall 40a, and the cylindrical wall 40b is slidably fitted into a boss hole 38a at the center of the control unit case 38. Further, the inclined wall 40a is inclined toward the bottom wall side of the control unit case 38 from the axial center portion toward the radially outer side, and receives the urging force in the axial direction by the coil spring 41 to move the weight roller 39 in the radially inner direction. It comes to hold down. Conversely, when the weight roller 39 rolls radially outward due to centrifugal force, the inclined wall 40a converts the centrifugal force into the axial displacement of the movable cam member 40, and the operating rod 32 is attached to the coil spring 41. The bypass passage 31 is displaced against the force in a direction to close the bypass passage 31 (right side in FIGS. 1 and 9). The urging force of the coil spring 41 acts on the operating rod 32 in the direction in which the annular groove 35 opens the bypass passage 31.
The movable cam member 40 and the coil spring 41 constitute an operation conversion mechanism that converts an operation along the radial direction of the weight roller 39 (centrifugal member) into an operation along the axial direction and transmits an operation force to the clutch mechanism 30. .

  A clutch assist device 50 is provided at the end of the transmission housing 3A so as to cover the front surface of the rod controller 33 as shown in FIGS. The clutch assist device 50 applies an assist force in the same direction as the operation force of the operation rod 32 due to the centrifugal force of the weight roller 39 to the operation rod 32 under the control of a controller (not shown). It is obtained by the hydraulic pressure of a lubrication pump (not shown).

  Specifically, in the clutch assist device 50, a cylinder hole 52 is formed in a device body 51 that is bolted to the transmission housing 3A, and a piston 53 is slidably accommodated in the cylinder hole 52. A push rod 54 is formed integrally with the piston 53, and the push rod 54 projects through the through hole 55 of the apparatus body 51 to the control unit case 38 side. A working chamber 56 is formed between the bottom of the cylinder hole 52 and the piston 53, and hydraulic pressure generated by a hydraulic control circuit 57 described later is introduced into the working chamber 56. A coil spring 58 (biasing means) that urges the piston 53 in the direction of the working chamber 56 is provided on the front side of the piston 53, and the piston 53 moves forward and backward by a balance between the hydraulic pressure of the coil spring 58 and the working chamber 56. It is supposed to be. On the other hand, the front end portion of the push rod 54 faces the axial center portion of the control unit case 38, but the proximity sensor 59 is placed on the cylindrical wall 40 b of the movable cam member 40 fitted in the boss hole 38 a of the axial center portion. A fixing bolt 60 for connecting the target plate 59a is screwed. The head 60a of the fixing bolt 60 is formed in a flat spherical shape, and the tip of the push rod 54 comes into contact with the center of the head. Therefore, the urging force by the piston 53 is transmitted to the operation rod 32 via the push rod 54 and the fixing bolt 60.

  As shown in FIGS. 3 and 4, the hydraulic control circuit 57 is configured so that the introduction passage 61 that is electrically connected to the working chamber 56 is selectively connected to the supply passage 63 and the drain passage 64 by the control spool 62 for switching the passage. It has become. The supply passage 63 is connected to a lubrication pump via a connection pipe (not shown), and the drain passage 64 communicates with the rod control unit 33 side as shown in FIG. Accordingly, the hydraulic oil discharged from the drain passage 64 goes around the rod control unit 33 and is used for lubricating the bearing 4 and the like.

  The control spool 62 is housed in the spool housing chamber 65 of the apparatus body 51 so as to be able to advance and retreat, and the control oil pressure acting on one end of the spool 62 and the force of the biasing spring 66 acting on the other end are accommodated in the spool housing chamber 65. It can be selectively switched between two positions. In the spool accommodating chamber 65, a supply port 67 that conducts to the supply passage 63, an introduction port 68 that conducts to the introduction passage 61, and a drain port 69 that conducts to the drain passage 64 are provided apart from each other in the axial direction. When the spool 62 is positioned on one end side, the first annular groove 62a on the outer periphery of the control spool 62 connects the introduction port 68 and the supply port 67 (see FIGS. 3 and 4), and the control spool 62 has the other end. When positioned on the side, the second annular passage 62b on the outer periphery of the control spool 62 allows the introduction port 68 and the drain port 69 to conduct (see FIGS. 6 and 7).

Further, the control hydraulic pressure acting on one end of the control spool 62 is created by control by an electromagnetic valve 70 (electrically controlled valve) shown in FIG.
The electromagnetic valve 70 includes a valve body 71 fixedly disposed in the apparatus body 51 and a valve body 73 that moves forward and backward by turning on and off the solenoid 72, and the valve body 71 is electrically connected to one end of the spool housing chamber 65. A supply / discharge hole 74 is formed. The valve body 71 is further formed with a high-pressure introduction path 75 that connects the supply / discharge hole 74 and the supply path 63, and a discharge path 76 that connects the supply / discharge hole 74 and the drain path 64. The supply / exhaust hole 74 can be selectively connected to either the high-pressure introduction path 75 or the discharge path 76 by advancing / retreating operation. Therefore, the electromagnetic valve 70 can switch the position of the control spool 62 by turning on / off the solenoid 72, thereby controlling the assist of the operating rod 32 by the piston 53. The valve body 73 is advanced and retracted by receiving the force of the urging spring 80 and the magnetic force of the solenoid 72. When the solenoid 72 is off, the supply / discharge hole 74 is connected to the high pressure introduction path 75 side. Yes. In FIG. 5, reference numeral 77 denotes a check valve that closes the high-pressure introduction path 75, and the check valve 77 is opened by being pressed by the valve body 73.

Here, the solenoid 72 is controlled by the controller based on an input signal corresponding to the driving state of the vehicle such as the vehicle speed.
Hereinafter, the operation of the clutch assist device 50 when the solenoid 72 is controlled according to the vehicle speed will be described.

  The controller determines whether or not the current vehicle speed is equal to or lower than the set vehicle speed in the low speed range. If the current vehicle speed exceeds the set vehicle speed, the solenoid 72 is turned off and the supply / discharge hole 74 is opened to the high-pressure introduction path 75. (See FIG. 5). At this time, the high pressure of the supply passage 63 acts on one end side of the control spool 62. As a result, the control spool 62 is displaced in the right direction in the drawing as shown in FIGS. Is introduced from the introduction passage 61 into the working chamber 56 via the first annular groove 62a (see arrows in FIGS. 3 and 4). As a result, the push rod 54 of the clutch assist device 50 moves forward, and an assist force by hydraulic pressure is applied to the operation rod 32. When the input drum 1 is at a predetermined rotational speed or higher, the operation rod 32 has already been moved forward by the centrifugal force of the weight roller 39. Therefore, in this case, since the operating rod 32 is in the forward position anyway, the bypass passage 31 is closed and the clutch mechanism 30 is in the connected state.

  Further, when the controller determines that the current vehicle speed is equal to or lower than the set vehicle speed, the solenoid 72 is turned on to connect the supply / discharge hole 74 to the discharge path 76 side (see FIG. 5). At this time, the hydraulic oil on one end side of the control spool 62 is discharged, and as a result, the control spool 62 is displaced in the left direction as shown in FIGS. 6 and 7, and the hydraulic oil in the working chamber 56 is introduced into the introduction passage. 61 and the second annular groove 62b to be discharged to the drain passage 64 (see arrows in FIGS. 6 and 7). Thereby, the push rod 54 moves backward, and the application of the assist force by the clutch assist device 50 is released. Therefore, if the rotational speed of the input drum 1 is lower than the predetermined rotational speed at this time, the operating rod 32 is retracted by receiving the force of the coil spring 41, the bypass passage 31 is opened, and the clutch mechanism 30 is in a power cut-off state. .

  In the clutch assist device 50 of this embodiment, even when the rotational speed of the input drum 1 decreases below a predetermined speed, the assist force by the clutch assist device 50 is applied to the clutch mechanism 30 as long as the vehicle speed does not become the set vehicle speed or less. Therefore, the engine braking force can continue to be applied to the drive wheels until the vehicle speed is sufficiently decelerated during braking or the like.

Further, the clutch assist device 50 is attached to the end of the transmission housing 3A in the axial direction, and has a structure that applies the pressing force of the push rod 54 to the operating rod 32 via the fixing bolt 60, so that it is compact and simple. The clutch mechanism 30 can be reliably assisted while having a simple structure.
Furthermore, since the clutch assist device 50 has a structure in which the hydraulic oil to be applied to the piston 53 is switched by on / off control of the electromagnetic valve 70, there is an advantage that control by the controller becomes easy.

  In this embodiment, since the proximity sensor 59 is provided in the clutch assist device 50, the operation status of the clutch mechanism 30 is fed back to the controller based on the detection signal of the proximity sensor 59, and the clutch assist device 50 is used. It can be controlled accurately.

  In the above, the electromagnetic valve 70 of the clutch assist device 50 is controlled according to the vehicle speed. However, the control of the electromagnetic valve 70 is not limited to the vehicle speed, and other operation state signals are input to the controller to appropriately control the electromagnetic valve. It is also possible to control 70. For example, the rotation speed signal of the input drum 1 may be input to the controller, and the on / off timing of the clutch assist device 50 may be changed between when the clutch mechanism 30 is connected and when it is disconnected. In this case, frequent disconnection of the clutch mechanism 30 in a predetermined rotation range can be avoided.

Further, the hydrostatic continuously variable transmission described above can change the inclination angle of the swash plate 12 in a stepwise manner in conjunction with the lever operation by the driver, thereby realizing a quasi stepped speed change. it can. When performing a shift in such a so-called manual mode, for example, if a half-clutch state is established when the rotational speed of the input drum 1 is between N1 and N2 shown in FIG. Position), when the throttle speed is reduced to the half-clutch speed range, and then the throttle is opened again, the time until the vehicle speed is restored to V1 becomes longer due to slipping of the clutch mechanism.
When the clutch assist device 50 according to the present invention is employed, for example, it is in the manual mode, the rotation speed of the input drum 1 has entered the half-clutch speed range from N1 or higher due to the closing operation of the throttle, and the throttle is opened again. If the assist force of the clutch assist device 50 acts on the clutch mechanism 30 under such conditions, the acceleration feeling can be improved by eliminating the slippage of the clutch mechanism at an early stage.

In addition, this invention is not limited to said embodiment, A various design change is possible in the range which does not deviate from the summary. For example, in the above embodiment, the hydrostatic continuously variable transmission employing the centrifugal clutch device according to the present invention is applied to a motorcycle. However, the hydrostatic continuously variable transmission is not limited to a motorcycle. The present invention can also be applied to other vehicles such as rough terrain vehicles.
In the above embodiment, the proximity sensor is provided between the device body of the clutch assist device and the operation rod. However, when the proximity sensor is not provided, the fixing bolt for attaching the target plate of the proximity sensor is eliminated. The rod portion that contacts the end of the push rod may be formed integrally with the movable cam member. In this case, the number of parts can be reduced and the structure can be simplified.
In the above embodiment, the structure is such that the solenoid 72 is turned off and the supply / discharge hole 74 is connected to the high pressure introduction path 75 side. However, when the switch is turned on, the supply / discharge hole is connected to the high pressure introduction path side. It is also possible to do.

The expanded sectional view of the principal part of FIG. 2 which shows one Embodiment of this invention. The sectional view of the hydrostatic continuously variable transmission which shows the embodiment and to which the centrifugal clutch device for vehicles concerning this invention is applied. FIG. 2 is a view as viewed in the direction of arrow A in FIG. 1, showing the same embodiment, with a part of the clutch assist device broken when the control spool is in the initial position. FIG. 2 is a view showing the clutch assist device when the control spool is in the initial position, as viewed in the direction of the arrow B in FIG. The longitudinal cross-sectional view of the electromagnetic valve employ | adopted as the clutch assist apparatus of the embodiment. FIG. 2 is a view as viewed in the direction of the arrow A in FIG. 1, showing the same embodiment, with a part of the clutch assist device broken when the control spool is operated. FIG. 2 is a view of the clutch assist device as viewed in the direction of arrow B in FIG. 1 when the control spool is activated, showing the embodiment. The expanded sectional view in case the clutch mechanism is an OFF state which shows the embodiment. The expanded sectional view which shows the same embodiment and a clutch mechanism is an ON state. The rotational speed-vehicle speed characteristic figure explaining the disconnection state of a clutch mechanism when the hydrostatic continuously variable transmission of the embodiment is used in a manual mode.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Input drum (power source side rotation element) 2 ... Output shaft (wheel side rotation element) 30 ... Clutch mechanism 39 ... Weight roller (centrifugal member) 40 ... Movable cam member (operation conversion mechanism) 41 ... Coil spring ( 50. Clutch assist device 70 ... Electromagnetic valve (electrically controlled valve)

Claims (2)

A clutch mechanism for connecting and disconnecting the rotating element on the power source side and the rotating element on the wheel side;
A centrifugal member that rotates integrally with the rotating element on the power source side and biases the clutch mechanism toward the connection side by centrifugal force;
Spring means for applying a spring force against the centrifugal force to the centrifugal member, and urging the clutch mechanism in a shut-off direction;
In a vehicle centrifugal clutch device comprising:
A clutch assist device is provided for applying an operating force to the clutch mechanism by electrical control according to the driving situation of the vehicle,
An operation conversion mechanism that converts an operation along the radial direction of the centrifugal member into an operation along the axial direction and transmits an operation force to the clutch mechanism is provided,
The clutch assist device is a centrifugal clutch device for a vehicle, wherein an operation force by hydraulic pressure is applied to an axially movable portion of the operation conversion mechanism. The centrifugal clutch device for a vehicle according to claim 1, wherein the clutch assist device includes an electrically controlled valve that switches between supply and discharge of hydraulic pressure .

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