JP2013024290A - Power transmission device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power transmission device which can control an increase of load applied to a clutch due to a weight increase of a vehicle.SOLUTION: The power transmission device includes a non stage transmission device 35 having a drive pulley rotating with engine rotation, and a driven pulley 42 connected with the drive pulley through a drive belt 41; and a planetary transmission device 37 having a first input rotation part 60 mounted rotation-integrally with the driven pulley 42, a second input rotation part 57 connected to the driven pulley 42 via a clutch 36, an output rotation part 59 which transmits the rotation of the first input rotation part 60 and the second input rotation part 57 into a drive wheel side 12 by changing the rotation transmission ratio according to the connecting state of the clutch 36.

Description

  The present invention relates to a power transmission device for transmitting engine power to drive wheels.

  2. Description of the Related Art Conventionally, in a vehicle such as a motorcycle, a power transmission device for transmitting engine power to driving wheels (usually rear wheels in the case of a motorcycle) is provided. For example, in the case of a so-called scooter type motorcycle in which a flat footrest is provided in front and lower of the driver's seat, a configuration in which a power transmission device combining a continuously variable transmission and a centrifugal clutch is formed integrally with an engine is used. (See Patent Document 1).

  The above-described continuously variable transmission is usually configured such that an endless V-belt is wound between a driving pulley and a driven pulley arranged side by side in the front-rear direction, depending on the rotational speed of the crankshaft of the engine. As the movable part of the drive pulley moves in the axial direction of the crankshaft, the gear ratio is changed steplessly.

  Further, the centrifugal clutch described above is normally disposed rotatably on the driven shaft together with the driven pulley. When the driven pulley rotates at a certain rotational speed or more, the centrifugal clutch is engaged and the rotation of the driven pulley is transmitted to the driven shaft, and the rotation of the driven shaft is decelerated by the intermediate shaft and then to the drive wheel. It is to be transmitted.

JP-A-1-237284

  However, in the power transmission device described above, when the weight of the vehicle increases with an increase in the size of the vehicle (especially an increase in the size of the drive wheels), the load applied to the centrifugal clutch increases, and the centrifugal clutch may be worn out early. There was. If the centrifugal clutch wears out early in this manner, the frequency of replacement of the centrifugal clutch increases, and there is a possibility that the maintenance work becomes complicated.

  In view of the above circumstances, an object of the present invention is to provide a power transmission device that can suppress an increase in a load applied to a clutch as the weight of a vehicle increases.

  The present invention is a power transmission device for transmitting engine power to drive wheels, a drive pulley that rotates as the engine rotates, and a driven pulley connected to the drive pulley via a drive belt. Depending on the connection state of the clutch, a continuously variable transmission including: a first input rotating portion provided integrally with the driven pulley; a second input rotating portion connected to the driven pulley via a clutch; And a planetary transmission having an output rotation unit that transmits the rotation of the first input rotation unit and the second input rotation unit to the drive wheel side while changing the rotation transmission rate. Features.

  Thus, by using the clutch and the planetary transmission together, it is possible to disperse the load that was conventionally applied only to the clutch to the clutch and the planetary transmission. Accordingly, the load applied to the clutch can be reduced, and even when the weight of the vehicle increases, the wear of the clutch can be suppressed and the life of the clutch can be extended. Therefore, it is possible to reduce the clutch replacement frequency and prevent problems such as complicated maintenance work.

  The clutch is a centrifugal clutch disposed on the opposite side of the planetary transmission with the driven pulley interposed therebetween. The planetary transmission includes a sun gear, a planetary gear meshing with the sun gear, and the planetary gear. A planetary carrier that supports a gear; and an outer ring gear that meshes with the planetary gear, wherein the outer ring gear is the first input rotation unit, the sun gear is the second input rotation unit, and the planet carrier is the It is good also as an output rotation part.

  Such a configuration is suitable when a dry clutch is employed as the centrifugal clutch. Further, by adopting such a configuration, it is possible to transmit a larger torque from the planet carrier to the rear wheel side when starting the vehicle than when the vehicle is in steady running. Along with this, it is possible to obtain torques suitable for starting and steady running of the vehicle, thereby improving both fuel efficiency and acceleration performance.

  The clutch is a centrifugal clutch disposed on the opposite side of the planetary transmission with the driven pulley interposed therebetween. The planetary transmission includes a sun gear, a planetary gear meshing with the sun gear, and the planetary gear. A planetary carrier that supports a gear; and an outer ring gear that meshes with the planetary gear, wherein the planetary carrier is the first input rotating unit, the sun gear is the second input rotating unit, and the outer ring gear is the It is good also as an output rotation part.

  Such a configuration is suitable when a dry clutch is employed as the centrifugal clutch. Further, by adopting such a configuration, it is possible to transmit a larger torque from the outer ring gear to the rear wheel side when starting the vehicle than when the vehicle is in steady running. Along with this, it is possible to obtain torques suitable for starting and steady running of the vehicle, thereby improving both fuel efficiency and acceleration performance.

  The clutch is a centrifugal clutch disposed between the driven pulley and the planetary transmission, and the planetary transmission supports a sun gear, a planetary gear meshing with the sun gear, and the planetary gear. A planetary carrier and an outer ring gear meshing with the planetary gear, wherein the sun gear is the first input rotation unit, the outer ring gear is the second input rotation unit, and the planet carrier is the output rotation unit. Also good.

  Such a configuration is suitable when a wet clutch is employed as the centrifugal clutch. Further, by adopting such a configuration, it is possible to transmit a larger torque from the planet carrier to the rear wheel side when starting the vehicle than when the vehicle is in steady running. Along with this, it is possible to obtain torques suitable for starting and steady running of the vehicle, thereby improving both fuel efficiency and acceleration performance.

  The clutch is a centrifugal clutch disposed between the driven pulley and the planetary transmission, and the planetary transmission supports a sun gear, a planetary gear meshing with the sun gear, and the planetary gear. A planetary carrier and an outer ring gear meshing with the planetary gear, wherein the sun gear is the first input rotation unit, the planet carrier is the second input rotation unit, and the outer ring gear is the output rotation unit. Also good.

  Such a configuration is suitable when a wet clutch is employed as the centrifugal clutch. Further, by adopting such a configuration, it is possible to transmit a larger torque from the outer ring gear to the rear wheel side when starting the vehicle than when the vehicle is in steady running. Along with this, it is possible to obtain torques suitable for starting and steady running of the vehicle, thereby improving both fuel efficiency and acceleration performance.

  The clutch includes a clutch shoe provided integrally with the sun gear, and a clutch housing disposed on the outer periphery of the clutch shoe and provided integrally with the planet carrier, and stops the rotation of the clutch housing. A braking device may be provided.

  By adopting such a configuration, it becomes possible to stop the rotation of the clutch housing and the planetary carrier integrally by the braking device, and with this rotation stop, the direction opposite to the rotation of the clutch housing and the planetary carrier is achieved. Torque can be generated in the outer ring gear. Therefore, it becomes possible to use the power transmission device for advancing and reversing the vehicle.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the power transmission device which can suppress that the load added to a clutch increases with the increase in the weight of a vehicle.

1 is a left side view showing a motorcycle according to a first embodiment of the present invention. 1 is a left side view showing a power unit in a motorcycle according to a first embodiment of the present invention. FIG. 3 is a cross-sectional view taken along the line AA in FIG. 2. It is a principal part enlarged view of FIG. In the planetary transmission of the motorcycle according to the first embodiment of the present invention, (a) is a schematic diagram showing a state in which an outer ring gear and a sun gear are rotating in opposite directions, and (b) is an outer ring. It is a schematic diagram which shows the state which the gearwheel and the sun gear are rotating differentially, (c) is a schematic diagram which shows the state in which the outer ring | wheel gear and the sun gear are rotating synchronously. In the power transmission device for a motorcycle according to the first embodiment of the present invention, (a) is a schematic view showing a state where the centrifugal clutch is disconnected, and (b) is a state where the centrifugal clutch is connected. It is a schematic diagram shown. FIG. 6 is a schematic diagram showing a power transmission device for a motorcycle according to a second embodiment of the present invention. FIG. 6 is a schematic diagram showing a power transmission device for a motorcycle according to a third embodiment of the present invention. It is a schematic diagram which shows the power transmission device of the motorcycle which concerns on the 4th Embodiment of this invention.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In the following first to fourth embodiments, a case where the present invention is applied to a small scooter type motorcycle 1 (hereinafter, abbreviated as “motorcycle 1”) will be described.

<First Embodiment>
First, the overall configuration of the motorcycle 1 will be described. Hereinafter, the directions of up and down, left and right, and front and rear indicate directions viewed from the driver who rides the motorcycle 1. Note that an arrow Fr appropriately shown in each drawing indicates the front of the vehicle.

  As shown in FIG. 1, the motorcycle 1 is provided with an underbone-type vehicle body frame 2 that constitutes a framework of the vehicle body. The body frame 2 includes a head pipe 3 disposed at the upper end of the front portion, a down tube 4 extending rearward and downward from the head pipe 3, and extending rearward and upward from the rear end of the down tube 4. The seat rail 5 is provided.

  A front fork 6 is rotatably supported on the head pipe 3 together with a handle bar 7. A front wheel 8 is pivotally supported at the lower end of the front fork 6, and a front fender 9 is provided so as to cover the front wheel 8.

  A front end portion of the power unit 11 is supported on the rear lower portion of the down tube 4 so as to be swingable in the vertical direction around the pivot shaft 10, and a rear wheel 12 is pivotally supported on the rear end portion of the power unit 11. Details of the power unit 11 will be described later. The periphery of the head pipe 3 and the down tube 4 is covered with a front cover 13 from the front and covered with a leg shield 14 from the rear.

  The seat rail 5 is covered with a frame cover 15, and a low floor footboard 16 is provided between the frame cover 15 and the leg shield 14 so that the driver can place his / her feet when getting on. . A rear fender 17 is provided at the rear end of the frame cover 15 so as to cover the upper part of the rear wheel 12, and a driver seat 18 is provided at the front upper side of the rear fender 17.

  Next, the power unit 11 will be described.

  As shown in FIG. 2, the power unit 11 includes an engine 19 and a power transmission device 21 provided behind the engine 19 and covered with a belt case 20.

  The engine 19 is, for example, an SOHC air-cooled single cylinder type, and includes a crankcase 22 and a cylinder assembly 23 that protrudes forward from the crankcase 22 (precisely, a direction slightly inclined upward toward the front). And. As shown in FIG. 3, the cylinder assembly 23 includes a cylinder 24 projecting forward from the crankcase 22, a cylinder head 25 provided in front of the cylinder 24, and a head cover 26 covering the front surface of the cylinder head 25. I have.

  A crankshaft 27 is supported in the crankcase 22 along the vehicle width direction (left-right direction). The crankshaft 27 is connected via a connecting rod 30 to a piston 28 accommodated in the cylinder 24 so as to be able to reciprocate. The reciprocating motion of the piston 28 is converted into rotation of the crankshaft 27 via the connecting rod 30. It is configured.

  A cooling fan 31 is attached to the right end portion of the crankshaft 27, and a fan cover 32 is disposed so as to cover the cooling fan 31. And the cooling fan 31 rotates with rotation of the crankshaft 27, and the air introduced from the outside cools the inside of the cylinder 24 and the cylinder head 25.

  A combustion chamber 33 is formed between the cylinder 24 and the cylinder head 25. The combustion chamber 33 communicates with an intake port (not shown) opened on the upper surface of the cylinder head 25. An air cleaner 34 (see FIG. 1) and a fuel injection device (not shown) are connected to the intake port, and after the air introduced from the air cleaner 34 and the fuel injected from the fuel injection device are mixed, the intake air It is configured to be introduced into the combustion chamber 33 through a port.

  The combustion chamber 33 communicates with an exhaust port (not shown) opened on the lower surface of the cylinder head 25. An exhaust pipe (not shown) is connected to the exhaust port, and exhaust from the combustion chamber 33 is configured to be exhausted to the rear of the vehicle body via the exhaust port and the exhaust pipe.

  The power transmission device 21 includes a continuously variable transmission 35 provided from the left to the rear left of the rear portion of the engine 19, a centrifugal clutch 36 provided to the left of the rear portion of the continuously variable transmission 35, and a continuously variable transmission. A planetary transmission 37 provided on the right side of the rear portion of the device 35 and a reduction gear 38 provided behind the planetary transmission 37 are provided.

  The continuously variable transmission 35 includes a drive pulley 40 and a driven pulley 42 connected to the drive pulley 40 via an endless V-belt 41 as a drive belt.

  The drive pulley 40 is disposed at the left end portion of the crankshaft 27. The drive pulley 40 includes a fixed face 43 fixed to the crankshaft 27, and a movable face 44 that is disposed on the right side of the fixed face 43 and is slidable along the axial direction (left-right direction) of the crankshaft 27. Yes. A weight roller 45 is attached to the movable face 44.

  The driven pulley 42 is provided behind the drive pulley 40. The driven pulley 42 is disposed on the left side of the driven shaft 46 that is supported behind the crankshaft 27 along the vehicle width direction. The driven pulley 42 is disposed on the left side of the fixed face 48 fixed to a sleeve 47 rotatably attached to the outer periphery of the driven shaft 46, and is disposed along the axial direction (left-right direction) of the driven shaft 46. And a slidable movable face 50.

  The centrifugal clutch 36 is, for example, a dry clutch. As best shown in FIG. 4, the centrifugal clutch 36 is disposed at the left end portion of the driven shaft 46, and is disposed on the opposite side of the planetary transmission 37 with the driven pulley 42 interposed therebetween. The centrifugal clutch 36 includes a base plate 51 fixed to the left end of the sleeve 47, a clutch shoe 52 fixed to the base plate 51, and a clutch housing 53 provided so as to cover the outer periphery of the clutch shoe 52. Yes.

  A coil spring 54 is interposed between the base plate 51 and the movable face 50 of the driven pulley 42. The coil spring 54 biases the movable face 50 of the driven pulley 42 toward the fixed face 48 of the driven pulley 42. ing. The clutch housing 53 includes a fixed portion 55 fixed to the left end portion of the driven shaft 46, and a flange portion 56 that protrudes rightward from the fixed portion 55. The inner peripheral portion of the flange portion 56 is It faces the outer periphery of the clutch shoe 52.

  The planetary transmission 37 is disposed on the right side of the driven shaft 46, is housed in a liquid-tight state in the mission cover 49 together with the speed reduction device 38, and is immersed in oil. The planetary transmission device 37 includes a sun gear 57 as a second input rotation unit fixed to the right side of the driven shaft 46 and a plurality (for example, seven, see FIG. 5) of planetary gears 58 that mesh with the sun gear 57. And a planet carrier 59 as an output rotating part that supports the planetary gear 58, and an outer ring gear 60 as a first input rotating part that meshes with the planetary gear 58.

  The sun gear 57 is connected to the driven pulley 42 through the sleeve 47, the centrifugal clutch 36, and the driven shaft 46. The planet carrier 59 is disposed on the right side of the sun gear 57 and the planet gear 58 and is rotatably supported on the outer periphery of the driven shaft 46 via a pair of bearings 61. A connection gear 63 is provided on the right side of the planet carrier 59. The outer ring gear 60 is provided from the left side of the sun gear 57 and the planetary gear 58 to the outer periphery of the planetary gear 58, and is rotatably supported on the outer periphery of the driven shaft 46 via a bearing 62. The left end portion of the outer ring gear 60 is fixed to the right end portion of the sleeve 47.

  The speed reduction device 38 includes an intermediate shaft 64 that is supported behind the driven shaft 46 along the vehicle width direction, a first intermediate gear 65 that is fixed to the intermediate shaft 64 and meshes with the connection gear 63 of the planet carrier 59, A second intermediate gear 66 provided on the intermediate shaft 64; an output gear 68 that is attached to an output shaft 67 that is supported behind the intermediate shaft 64 along the vehicle width direction and meshes with the second intermediate gear 66; It has. The rotation of the planet carrier 59 is transmitted to the rear wheel 12 attached to the output shaft 67 via the speed reduction device 38.

  The operation of the continuously variable transmission 35 having the above-described configuration will be described.

  When the rotational speed of the crankshaft 27 of the engine 19 increases and the centrifugal force applied to the weight roller 45 increases, the weight roller 45 presses and moves the movable face 44 of the drive pulley 40 toward the fixed face 43. The winding radius of the V belt 41 in the drive pulley 40 is increased. On the other hand, the movable face 50 of the driven pulley 42 moves away from the fixed face 48 of the driven pulley 42 against the urging force of the coil spring 54, and the winding radius of the V belt 41 on the driven pulley 42 becomes small.

  In this way, the winding radius of the V-belt 41 in the driving pulley 40 and the driven pulley 42 is adjusted steplessly, and accordingly, the rotation of the engine 19 is steplessly changed and transmitted to the driven pulley 42. .

  The operation of the centrifugal clutch 36 and the planetary transmission 37 in the configuration as described above will be described.

  As described above, when the rotation of the engine 19 is transmitted to the driven pulley 42, the driven pulley 42, the sleeve 47, the base plate 51, the clutch shoe 52, and the outer ring gear 60 rotate together. When the outer ring gear 60 rotates in this way, as shown in FIG. 5A, the planetary gear 58 rotates in the same direction as the outer ring gear 60, and accordingly, the sun gear 57 rotates the outer ring gear 60 and the planetary gear. It rotates in the opposite direction to 58.

  Until the rotational speed of the engine 19 reaches a certain number, as shown in FIG. 6A, the clutch shoe 52 of the centrifugal clutch 36 is separated from the clutch housing 53, and the centrifugal clutch 36 is disconnected. Therefore, the rotation of the driven pulley 42 is not transmitted to the sun gear 57 via the sleeve 47, the centrifugal clutch 36 and the driven shaft 46. Accordingly, the planetary gear 58 does not revolve around the sun gear 57 but only rotates, so that the planet carrier 59 does not transmit the rotation of the outer ring gear 60 and the sun gear 57 to the rear wheel 12 side. The motorcycle 1 is stopped. That is, the rotation transmissibility (<the rotation speed of the output rotation section (the planet carrier 59 in the present embodiment)> / <the rotation speed of the driven pulley 42>) is zero. Hereinafter, this state is referred to as an “idling state”.

  Even in this idling state, the rotation of the driven pulley 42 is transmitted to the clutch housing 53 through the sleeve 47, the outer ring gear 60, the planetary gear 58, the sun gear 57, and the driven shaft 46, and the clutch housing 53 rotates. doing.

  When the rotational speed of the engine 19 is increased for starting the vehicle from this idling state, the rotational speeds of the driven pulley 42, the sleeve 47, the base plate 51, the clutch shoe 52, and the outer ring gear 60 are also increased and applied to the clutch shoe 52. Centrifugal force increases. Accordingly, as shown in FIG. 6B, the clutch shoe 52 starts to contact the clutch housing 53, and the centrifugal clutch 36 shifts from the disconnected state to the sliding state. Thereby, the rotation of the driven pulley 42 is decelerated and transmitted to the sun gear 57 via the sleeve 47, the centrifugal clutch 36 and the driven shaft 46.

  In this way, when the rotation of the driven pulley 42 is decelerated and transmitted, the torque in the same direction as the rotation direction of the outer ring gear 60 is applied to the sun gear 57 as shown in FIG. . In other words, torque in the direction opposite to the torque applied to the sun gear 57 when the centrifugal clutch 36 is disconnected is applied to the sun gear 57. Along with this, the planetary gear 58 continues to rotate, and the sun gear 57 rotates at a rotation speed (rotation speed smaller than the rotation speed of the outer ring gear 60) according to the differential rotation of the outer ring gear 60 and the sun gear 57. Begins to revolve in the same direction as the outer ring gear 60. Along with this, the planet carrier 59 starts rotating, and the rotation of the planet carrier 59 is transmitted to the output shaft 67 after being decelerated by the reduction gear 38, and the rear wheel 12 attached to the output shaft 67 rotates. . At this time, the rotation transmission rate is larger than 0 and smaller than 1. Hereinafter, this state is referred to as a “differential rotation state”.

  If the rotational speed of the engine 19 is further increased for steady running of the vehicle from this differential rotational state, the rotational speeds of the driven pulley 42, the sleeve 47, the base plate 51, the clutch shoe 52, and the outer ring gear 60 are further increased. The centrifugal force applied to the clutch shoe 52 is further increased. Along with this, the clutch shoe 52 comes into contact with the clutch housing 53 so as not to be relatively rotatable, and the centrifugal clutch 36 shifts from the sliding state to the locked state. Accordingly, the rotation of the driven pulley 42 is transmitted to the sun gear 57 without being decelerated through the sleeve 47, the centrifugal clutch 36, and the driven shaft 46.

  As described above, when the rotation of the driven pulley 42 is transmitted to the sun gear 57 without being decelerated, the rotation speed of the sun gear 57 becomes the same as the rotation speed of the outer ring gear 60. That is, the outer ring gear 60 and the sun gear 57 rotate synchronously. Accordingly, as shown in FIG. 5C, the rotation of the planetary gear 58 stops, and the planetary gear 58 rotates around the sun gear 57 at the same rotational speed as the outer ring gear 60. Revolves in the same direction. Along with this, the planetary carrier 59 rotates at the same rotational speed as the driven pulley 42, and the rotation of the planetary carrier 59 is transmitted to the output shaft 67 after being decelerated by the reduction gear 38 and attached to the output shaft 67. The rear wheel 12 rotates at a higher speed than in the differential rotation state. At this time, the rotation transmission rate is 1. Hereinafter, this state is referred to as a “synchronous rotation state”.

  As described above, in the present embodiment, the centrifugal clutch 36 and the planetary transmission 37 are used in combination, and the load that was conventionally applied only to the centrifugal clutch 36 is distributed to the centrifugal clutch 36 and the planetary transmission 37. Is possible. Accordingly, it is possible to reduce the load applied to the centrifugal clutch 36, and even if the weight of the motorcycle 1 increases with an increase in the size of the wheels, the wear of the centrifugal clutch 36 is suppressed, and the centrifugal clutch It is possible to extend the life of 36. Therefore, it is possible to reduce the replacement frequency of the centrifugal clutch 36 and prevent problems such as complicated maintenance work.

  In the present embodiment, the idling state, the differential rotation state, and the synchronous rotation state can be automatically switched by changing the rotation transmission rate according to the connection state of the centrifugal clutch 36. Therefore, for example, compared with the case where the above-described switching is realized by using the centrifugal clutch 36 together with the shift clutch and the one-way clutch, the number of parts is reduced, and the manufacturing cost is reduced and the reliability and productivity are reduced. It is possible to improve.

  In addition, the dry centrifugal clutch 36 is disposed on the opposite side of the planetary transmission 37 with the driven pulley 42 interposed therebetween. Such a layout is obtained by replacing the dry centrifugal clutch 36 with the mission cover 49 as in this embodiment. It is suitable when arranged outside.

  Further, in the present embodiment, the outer ring gear 60 is the first input rotation unit, the sun gear 57 is the second input rotation unit, and the planet carrier 59 is the output rotation unit. By adopting such a configuration, it becomes possible to make the rotational transmission rate in the differential rotational state smaller than the rotational transmission rate in the synchronous rotational state, and accordingly, the torque in the differential rotational state is synchronized with the synchronous rotational state. It is possible to make it larger than the torque at. Therefore, it is possible to transmit a larger torque from the planet carrier 59 to the rear wheel 12 when starting the vehicle, and to obtain torques suitable for starting the vehicle and steady driving, respectively. And acceleration performance can be improved.

  Further, in the present embodiment, as described above, the clutch housing 53 can be always rotated even in the idling state, so that the clutch housing is compared with the case where the rotation of the clutch housing 53 is stopped in the idling state. The cooling performance of 53 can be enhanced.

<Second Embodiment>
Next, a second embodiment of the present invention will be described. Note that a description of the same components as those in the first embodiment will be omitted as appropriate.

  As shown in FIG. 7, in the second embodiment, as in the first embodiment, the dry centrifugal clutch 36 is disposed on the opposite side of the planetary transmission device 37 with the driven pulley 42 interposed therebetween. Such a layout is suitable when the dry centrifugal clutch 3 is disposed outside the mission cover 49 that houses the planetary transmission 37 and the speed reduction device 38 in a liquid-tight state.

  In the second embodiment, the planet carrier 59 is fixed to the driven pulley 42 via the sleeve 47, and the planet carrier 59 and the driven pulley 42 are integrally rotated. That is, the planet carrier 59 is used as the first input rotation unit. The sun gear 57 is connected to the driven pulley 42 via the sleeve 47, the centrifugal clutch 36 and the driven shaft 46. That is, the sun gear 57 is used as the second input rotating unit. The outer ring gear 60 is provided with a connection gear 63, and the first intermediate gear 65 of the reduction gear 38 is meshed with the connection gear 63. In other words, the outer ring gear 60 is used as the output rotating portion.

  By adopting such a configuration, the rotation transmission rate in the differential rotation state (<the rotation speed of the output rotation section (the outer ring gear 60 in the present embodiment)> / <the rotation speed of the driven pulley 42>) is in the synchronous rotation state. Accordingly, the torque in the differential rotation state can be made larger than the torque in the synchronous rotation state. Therefore, it is possible to transmit a larger torque from the outer wheel gear 60 to the rear wheel 12 when starting the vehicle, and to obtain a torque suitable for both starting and steady driving of the vehicle. And acceleration performance can be improved.

  Further, according to the above-described configuration, the rotation direction of the clutch shoe 52 and the clutch housing 53 in the idling state can be made the same direction, and accordingly, the impact caused by the connection of the centrifugal clutch 36 can be reduced. It becomes possible.

<Third Embodiment>
Next, a third embodiment of the present invention will be described. Note that a description of the same components as those in the first embodiment will be omitted as appropriate.

  As shown in FIG. 8, in the third embodiment, the wet centrifugal clutch 36 is disposed between the driven pulley 42 and the planetary transmission 37. A spring receiver 70 is provided on the opposite side of the centrifugal clutch 36 and the planetary transmission 37 with the driven pulley 42 interposed therebetween. A coil spring interposed between the spring receiver 70 and the movable face 44 of the driven pulley 42. 54, the movable face 44 of the driven pulley 42 is urged toward the fixed face 43 side of the driven pulley 42. Such a layout is suitable when the wet centrifugal clutch 36 is arranged inside the mission cover 49 that houses the planetary transmission 37 and the speed reduction device 38 in a liquid-tight state.

  In the third embodiment, the driven pulley 42, the clutch shoe 52, and the sun gear 57 are fixed to the driven shaft 46, and the sun gear 57 and the driven pulley 42 are integrally rotated. That is, the sun gear 57 is used as the first input rotating unit. The outer ring gear 60 is formed integrally with the clutch housing 53 of the centrifugal clutch 36, and is connected to the driven pulley 42 via the driven shaft 46 and the centrifugal clutch 36. That is, the outer ring gear 60 is used as the second input rotating portion. The planetary carrier 59 is provided with a connection gear 63, and the first intermediate gear 65 of the reduction gear 38 meshes with the connection gear 63. In other words, the planet carrier 59 is used as the output rotation unit.

  By adopting such a configuration, the rotation transmission rate in the differential rotation state (<the rotation speed of the output rotation section (the planet carrier 59 in this embodiment)> / <the rotation speed of the driven pulley 42>) is in the synchronous rotation state. Accordingly, the torque in the differential rotation state can be made larger than the torque in the synchronous rotation state. Therefore, it is possible to transmit a larger torque from the planet carrier 59 to the rear wheel 12 when starting the vehicle, and to obtain torques suitable for starting the vehicle and steady driving, respectively. And acceleration performance can be improved.

<Fourth Embodiment>
Next, a fourth embodiment of the present invention will be described. Note that description of parts similar in configuration to those of the first embodiment or the third embodiment is omitted as appropriate.

  As shown in FIG. 9, in the fourth embodiment, a wet centrifugal clutch 36 is disposed between the driven pulley 42 and the planetary transmission 37 as in the third embodiment. Such a layout is suitable when the wet centrifugal clutch 36 is arranged inside the mission cover 49 that houses the planetary transmission 37 and the speed reduction device 38 in a liquid-tight state.

  In the fourth embodiment, the driven pulley 42, the clutch shoe 52, and the sun gear 57 are fixed to the driven shaft 46, and the sun gear 57 and the driven pulley 42 are integrally rotated. That is, the sun gear 57 is used as the first input rotating unit. The planet carrier 59 is provided to rotate integrally with the clutch housing 53 of the centrifugal clutch 36, and is connected to the driven pulley 42 via the driven shaft 46 and the centrifugal clutch 36. That is, the planetary carrier 59 is used as the second input rotation unit. The outer ring gear 60 is provided with a connection gear 63, and the first intermediate gear 65 of the reduction gear 38 is meshed with the connection gear 63. In other words, the outer ring gear 60 is used as the output rotating portion.

  By adopting such a configuration, the rotation transmission rate in the differential rotation state (<the rotation speed of the output rotation section (the outer ring gear 60 in the present embodiment)> / <the rotation speed of the driven pulley 42>) is in the synchronous rotation state. Accordingly, the torque in the differential rotation state can be made larger than the torque in the synchronous rotation state. Therefore, it is possible to transmit a larger torque from the outer wheel gear 60 to the rear wheel 12 when starting the vehicle, and to obtain a torque suitable for both starting and steady driving of the vehicle. And acceleration performance can be improved.

  Further, according to the above-described configuration, the rotation direction of the clutch shoe 52 and the clutch housing 53 in the idling state can be made the same direction, and accordingly, the impact caused by the connection of the centrifugal clutch 36 can be reduced. It becomes possible.

  In the fourth embodiment, a flange-like brake disk 71 projects from one side of the clutch housing 53. A braking device 72 is provided in the vicinity of the clutch housing 53, and a pair of brake pads 73 are provided on the braking device 72 so as to sandwich the brake disk 71 from both sides. Then, for example, when a back switch (not shown) disposed near the handle bar 7 is pressed, the brake device 72 is actuated to bring the brake pad 73 into contact with the brake disc 71 and the clutch housing 53. Is configured to stop rotating.

  In such a configuration, when the centrifugal clutch 36 is not connected and the brake device 72 is operated to bring the brake pad 73 into contact with the brake disk 71, the rotation of the clutch housing 53 and the planet carrier 59 stops, and the planetary gear 58 Revolution is suppressed. Along with this, torque is generated in the outer ring gear 60 in a direction opposite to that when the braking device 72 is not operated, and the connection gear 63 rotates in the reverse direction. Accordingly, the motorcycle 1 can be moved backward by rotating the rear wheel 12 backward. As described above, according to the configuration of the fourth embodiment, the power transmission device 21 can be used in combination for forward movement and backward movement of the motorcycle 1.

  As described above, as shown in the first to fourth embodiments, the present invention can be applied to both the dry centrifugal clutch 36 and the wet centrifugal clutch 36 by appropriately changing the layout.

  In the first to fourth embodiments, the case where the present invention is applied to the single-cylinder engine 19 has been described. However, other different types of engines such as a parallel two-cylinder type, a parallel four-cylinder type, and a V type may be used. The present invention may be applied. In the first to fourth embodiments, the case where the present invention is applied to the air-cooled engine 19 has been described. However, the present invention may be applied to other different types of engines such as a water-cooled engine. In the first to fourth embodiments, the case where the present invention is applied to the SOHC engine 19 has been described. However, the present invention may be applied to other different types of engines such as a DOHC engine.

  In the first to fourth embodiments, the configuration of the present invention is applied to the engine 19 of the scooter type motorcycle 1. However, in other different embodiments, the present invention is applied to an engine of an motorcycle such as an on-road type or an off-road type. You may apply the structure of invention. In addition, the configuration of the present invention may be applied to engines such as ATVs (roughly terrain vehicles), automobiles (four-wheeled vehicles), and snow vehicles. That is, the present invention can be applied to all vehicle engines.

  In 1st-4th embodiment, although this invention was applied to the power transmission device 21 provided with the centrifugal clutch 36 which switches connection and non-connection according to the rotation speed of the engine 19, in other different embodiment, You may apply this invention to the power transmission device 21 provided with the single plate-type or multi-plate type clutch which switches a connection state according to a driver | operator's clutch lever operation.

12 Rear wheels (drive wheels)
DESCRIPTION OF SYMBOLS 19 Engine 21 Power transmission device 35 Stepless transmission 36 Centrifugal clutch 37 Planetary transmission 40 Drive pulley 41 V belt (drive belt)
42 driven pulley 52 clutch shoe 53 clutch housing 57 sun gear 58 planetary gear 59 planet carrier 60 outer ring gear 72 braking device

Claims (6)

A power transmission device for transmitting engine power to drive wheels,
A continuously variable transmission having a drive pulley that rotates as the engine rotates, and a driven pulley connected to the drive pulley via a drive belt;
While changing the rotation transmissibility according to the connection state of the clutch, a first input rotation unit provided integrally with the driven pulley, a second input rotation unit connected to the driven pulley via a clutch, A power transmission device comprising: a planetary transmission including an output rotation unit that transmits rotation of the first input rotation unit and the second input rotation unit to the drive wheel side. The clutch is a centrifugal clutch disposed on the opposite side of the planetary transmission with the driven pulley interposed therebetween,
The planetary transmission device includes a sun gear, a planet gear that meshes with the sun gear, a planet carrier that supports the planet gear, and an outer ring gear that meshes with the planet gear,
The outer ring gear as the first input rotating unit,
The sun gear as the second input rotating unit,
The power transmission device according to claim 1, wherein the planetary carrier is the output rotation unit. The clutch is a centrifugal clutch disposed on the opposite side of the planetary transmission with the driven pulley interposed therebetween,
The planetary transmission device includes a sun gear, a planet gear that meshes with the sun gear, a planet carrier that supports the planet gear, and an outer ring gear that meshes with the planet gear,
The planet carrier is the first input rotation unit,
The sun gear as the second input rotating unit,
The power transmission device according to claim 1, wherein the outer ring gear is used as the output rotation unit. The clutch is a centrifugal clutch disposed between the driven pulley and the planetary transmission,
The planetary transmission device includes a sun gear, a planet gear that meshes with the sun gear, a planet carrier that supports the planet gear, and an outer ring gear that meshes with the planet gear,
The sun gear as the first input rotating unit,
The outer ring gear as the second input rotating unit,
The power transmission device according to claim 1, wherein the planetary carrier is the output rotation unit. The clutch is a centrifugal clutch disposed between the driven pulley and the planetary transmission,
The planetary transmission device includes a sun gear, a planet gear that meshes with the sun gear, a planet carrier that supports the planet gear, and an outer ring gear that meshes with the planet gear,
The sun gear as the first input rotating unit,
The planet carrier is the second input rotation unit,
The power transmission device according to claim 1, wherein the outer ring gear is used as the output rotation unit. The clutch includes a clutch shoe that is provided integrally with the sun gear, and a clutch housing that is provided on the outer periphery of the clutch shoe and provided integrally with the planet carrier.
The power transmission device according to claim 5, further comprising a braking device that stops rotation of the clutch housing.