JP2011252588A - Stepped automatic transmission device and motorcycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stepped automatic transmission device capable of properly generating engine break and a motorcycle with the same.SOLUTION: The stepped automatic transmission device 44 includes a crank journal 58d, an output shaft 36, a rotation shaft 128, a clutch housing 66, a centrifugal clutch part 82, a hydraulic clutch part 96, gears 70, 118, 134, 138, and a oneway clutches 80, 136. The rotation of the gear 138 is transmitted to the crank journal 58d via the gear 118, the hydraulic clutch part 96, the clutch housing 66, the gear 70, and the oneway clutch 80 in the case the hydraulic clutch part 96 is connected to the clutch housing 66 and the centrifugal clutch part 82 is spaced apart from the clutch housing 66. Thereby the engine brake is generated.

Description

  The present invention relates to a stepped automatic transmission and a motorcycle, and more particularly to a stepped automatic transmission having a gear position of at least two speeds and a motorcycle including the same.

  In recent years, various stepped automatic transmissions have been developed for the purpose of improving both durability and power transmission efficiency (see, for example, Patent Document 1).

FIG. 17 is a cross-sectional view showing a stepped automatic transmission disclosed in Patent Document 1. As shown in FIG.
As shown in FIG. 17, the stepped automatic transmission 1 (hereinafter abbreviated as the transmission 1) has an input shaft 2, intermediate shafts 3, 4, 5, 6, and 7, and an output shaft 8. The input shaft 2 is provided with a gear 2a, a centrifugal clutch 2b, a hydraulic clutch 2c, and a gear 2d. The centrifugal clutch 2b has an inner 2e, and the hydraulic clutch 2c has an inner 2f. The centrifugal clutch 2b and the hydraulic clutch 2c have a common outer 2g. The gear 2a, the gear 2d, the inner 2f, and the outer 2g are rotatable with respect to the input shaft 2. The inner 2e rotates integrally with the input shaft 2. The gear 2a and the outer 2g rotate integrally, and the inner 2f and the gear 2d rotate integrally. The intermediate shaft 3 is provided with a gear 3a (hereinafter referred to as a one-way gear 3a) and a gear 3b as a one-way rotation mechanism. The one-way gear 3a meshes with the gear 2a, and the gear 3b meshes with the gear 2d. The gear 3 b rotates integrally with the intermediate shaft 3.

  In the transmission 1, the inner 2e is connected to the outer 2g when the vehicle (not shown) starts, and the gear position is set to the first speed. Thereby, the rotation of the input shaft 2 is transmitted to the intermediate shaft 3 via the inner 2e, the outer 2g, the gear 2a, and the one-way gear 3a. The rotation transmitted to the intermediate shaft 3 is transmitted to the output shaft 8 via the intermediate shafts 4, 5, 6 and 7, and a plurality of gears. Thereby, a rear wheel (not shown) rotates.

  When the gear position of the transmission 1 is set to the second speed or higher, the inner 2f is connected to the outer 2g while the inner 2e is connected to the outer 2g. Thereby, the rotation of the input shaft 2 is transmitted to the intermediate shaft 3 via the inner 2e, the outer 2g, the inner 2f, the gear 2d, and the gear 3b. The rotation transmitted to the intermediate shaft 3 is transmitted to the output shaft 8 as in the case of the first speed described above. Thereby, a rear wheel (not shown) rotates. When the inner 2f is connected to the outer 2g, the one-way gear 3a rotates idly with respect to the intermediate shaft 3.

JP 2009-68700 A

  By the way, in the transmission 1, when the inner shaft 2e moves away from the outer 2g due to a decrease in the rotational speed of the input shaft 2 when the vehicle is decelerated, the input shaft can be connected even if the inner 2f and the outer 2g are connected. Rotational transmission between 2 and the gear 2a and rotational transmission between the input shaft 2 and the gear 2d are cut off. In this case, since the rotation transmission between the input shaft 2 and the output shaft 8 is interrupted, the vehicle travels inertially while the engine brake is not effective. That is, when the gear position of the transmission 1 is set to 2nd speed or more and the vehicle is decelerating, if the inner 2e moves away from the outer 2g due to a decrease in the rotational speed of the input shaft 2, the vehicle Transition from a state where the engine is working to a state where the engine brake is not working. At this time, a change occurs in the deceleration of the vehicle, which makes the driver uncomfortable.

  SUMMARY OF THE INVENTION Therefore, a main object of the present invention is to provide a stepped automatic transmission that can appropriately generate an engine brake and a motorcycle including the same.

  In order to achieve the above-mentioned object, the stepped automatic transmission according to claim 1 is a stepped automatic transmission having a gear position of at least two speeds, and an input shaft that rotates in a first direction. An output shaft that rotates based on the rotation transmitted from the input shaft, a clutch housing that is coaxial with the input shaft and that can be rotated relative to the input shaft, and an input shaft that is integral with the input shaft inside the clutch housing A first-speed centrifugal first clutch portion provided on the input shaft so as to rotate and be connected to the clutch housing based on centrifugal force, and provided so as to be rotatable relative to the input shaft on the same axis as the input shaft. And a second-speed hydraulic second clutch portion connected to the clutch housing when the gear position of the stepped automatic transmission is set to at least second-speed, and a first clutch When the clutch portion is connected to the clutch housing and the second clutch portion is not connected to the clutch housing, rotation is transmitted between the clutch housing and the output shaft, and the second clutch portion is connected to the clutch housing. A transmission mechanism for transmitting rotation between the second clutch portion and the output shaft, and transmitting rotation in the first direction from the clutch housing to the input shaft, and not transmitting rotation in the first direction from the input shaft to the clutch housing. A first transmission unit.

  The stepped automatic transmission according to claim 2 is the stepped automatic transmission according to claim 1, wherein the first transmission portion has a rotational speed in the first direction of the input shaft in the first direction of the clutch housing. When the rotation speed is higher than the rotation speed, the rotation is not transmitted between the input shaft and the clutch housing.

  The stepped automatic transmission according to claim 3 is the stepped automatic transmission according to claim 1 or 2, wherein the transmission mechanism includes an intermediate shaft provided between the input shaft and the output shaft, and an input shaft. A first gear provided coaxially with the shaft and rotating integrally with the clutch housing; a second gear provided coaxially with the input shaft and rotated integrally with the second clutch portion; and coaxial with the intermediate shaft A third gear that engages with the first gear, a fourth gear that engages with the second gear so as to rotate integrally with the intermediate shaft, and transmits the rotation of the fourth gear to the output shaft. A sub-transmission mechanism that transmits the rotation in the second direction opposite to the first direction from the third gear to the intermediate shaft, and the second transmission unit that does not transmit the rotation in the second direction from the intermediate shaft to the third gear; It is characterized by including.

  The stepped automatic transmission according to claim 4 is the stepped automatic transmission according to claim 3, wherein the clutch housing includes a hollow substantially disk-shaped plate portion extending in a radial direction of the input shaft, and at least A cylindrical portion extending substantially parallel to the input shaft from the plate portion so as to accommodate the first clutch portion therein; the first gear is fixed to the plate portion; and the first transmission portion is at least from the plate portion In the first clutch portion side, the first gear and the input shaft or the plate portion and the input shaft are connected.

  A motorcycle according to a fifth aspect includes the stepped automatic transmission according to any one of the first to fourth aspects.

  In the stepped automatic transmission according to claim 1, the first transmission portion does not transmit rotation in the first direction from the input shaft to the clutch housing. Therefore, when the first clutch portion and the clutch housing are not connected, even if the input shaft rotates in the first direction, the rotation of the input shaft is not transmitted to the clutch housing, and the rotation of the input shaft is not transmitted to the output shaft. Not transmitted.

  As the rotational speed of the input shaft increases, the first clutch portion is connected to the clutch housing by centrifugal force. As a result, the input shaft and the clutch housing rotate integrally in the first direction. The rotation transmitted from the input shaft to the clutch housing is transmitted to the output shaft via the transmission mechanism. As a result, the output shaft rotates.

  When the gear position of the stepped automatic transmission is set to at least the second speed, the second clutch portion is connected to the clutch housing. As a result, the clutch housing and the second clutch portion rotate integrally in the first direction. The rotation transmitted from the input shaft to the second clutch portion via the clutch housing is transmitted to the output shaft via the transmission mechanism. As a result, the output shaft rotates.

  Here, in the stepped automatic transmission, the first transmission unit transmits the rotation in the first direction from the clutch housing to the input shaft. Therefore, even if the first clutch portion is separated from the clutch housing due to a decrease in the rotational speed of the input shaft from the state in which the first clutch portion and the second clutch portion are both connected to the clutch housing, the first direction of the clutch housing Can be transmitted to the input shaft by the first transmission unit. Therefore, when the gear position of the stepped automatic transmission is at least 2nd speed (when the second clutch portion is connected to the clutch housing), even if the first clutch portion is separated from the clutch housing, the output shaft The rotation can be transmitted to the input shaft through the transmission mechanism, the second clutch portion, the clutch housing, and the first transmission portion. Thereby, an engine brake can be generated. As described above, in the stepped automatic transmission, when the gear position is at least the second speed, the engine brake can be appropriately generated even when the first clutch portion is separated from the clutch housing. Therefore, it is possible to prevent the vehicle deceleration from changing when the vehicle is decelerated. As a result, it is possible to prevent the driver from feeling uncomfortable.

  In the stepped automatic transmission according to claim 2, when the rotational speed of the input shaft is larger than the rotational speed of the clutch housing, the first transmission unit transmits the rotation between the input shaft and the clutch housing. do not do. Therefore, when the rotational speed of the input shaft becomes higher than the rotational speed of the clutch housing with the gear position of the stepped automatic transmission set to at least the second speed and the first clutch portion being away from the clutch housing. The rotation transmission between the input shaft and the clutch housing is cut off. In this case, since the rotation transmission from the output shaft to the input shaft is interrupted, the generation of the engine brake can be quickly stopped.

  In the stepped automatic transmission according to claim 3, when the rotation speed of the input shaft is increased and the first clutch portion is connected to the clutch housing, the rotation of the input shaft causes the clutch housing and the first gear to rotate. To the third gear. Thereby, the third gear rotates in the second direction. The rotation of the third gear in the second direction is transmitted to the intermediate shaft by the second transmission unit. As a result, the intermediate shaft and the fourth gear rotate in the second direction. The rotation of the fourth gear is transmitted to the output shaft through the sub transmission mechanism. As a result, the output shaft rotates.

  When the gear position of the stepped automatic transmission is set to at least the second speed, the second clutch portion is connected to the clutch housing, and the rotation of the input shaft is the first clutch portion, the clutch housing, the second clutch portion, And is transmitted to the fourth gear via the second gear. As a result, the fourth gear and the intermediate shaft rotate integrally in the second direction. Since the second transmission unit does not transmit the rotation of the intermediate shaft in the second direction to the third gear, the third gear rotates idly with respect to the intermediate shaft. The rotation of the fourth gear is transmitted to the output shaft through the sub transmission mechanism. As a result, the output shaft rotates.

  In this stepped automatic transmission, when the gear position of the stepped automatic transmission is at least the second speed (when the second clutch portion is connected to the clutch housing), the first clutch portion is the clutch housing. Even if it is away from the rotation, the rotation of the output shaft can be transmitted to the input shaft through the sub transmission mechanism, the fourth gear, the second gear, the second clutch portion, the clutch housing, and the first transmission portion. Thereby, an engine brake can be generated.

  Further, as described above, since the rotation of the fourth gear can be transmitted to the input shaft even when the first clutch portion is separated from the clutch housing, the means for transmitting the rotation of the fourth gear to the input shaft. There is no need to further provide (for example, a gear that meshes with the fourth gear and is provided on the input shaft via the one-way clutch). As a result, the stepped automatic transmission can be made compact.

  In the stepped automatic transmission according to claim 4, the first transmission portion connects the first gear and the input shaft or the plate portion and the input shaft at least on the first clutch portion side of the plate portion. In this case, since at least a part of the first transmission portion can be accommodated inside the clutch housing, a large space for providing the first transmission portion need not be secured outside the clutch housing. Thereby, the stepped automatic transmission can be configured more compactly.

  In order to enable smooth running in a motorcycle having a stepped automatic transmission, it is preferable to appropriately generate an engine brake during deceleration. Therefore, the stepped automatic transmission according to the present invention that can appropriately generate the engine brake can be suitably used for a motorcycle as described in claim 5.

  According to the present invention, a stepped automatic transmission that can appropriately generate engine braking and a motorcycle including the same are obtained.

1 is a side view showing a scooter to which a stepped automatic transmission according to the present invention is applied. It is a cross-sectional schematic solution figure which shows the internal structure of an engine unit. It is a side view solution figure which shows an engine unit. It is an illustration figure for demonstrating the structure of a 1st clutch unit and its periphery. It is an illustration figure for demonstrating operation | movement of a 1st clutch unit. It is an illustration figure for demonstrating the structure of a 2nd clutch unit and its periphery. It is an illustration figure which shows the supply route of hydraulic oil. It is an illustration figure for demonstrating operation | movement of the 3rd speed clutch. It is an illustration figure for demonstrating the operation | movement of a 4-speed clutch. It is an illustration for demonstrating the relationship between a crankshaft, a cell motor, and a kick pedal. It is a side view solution figure which shows an engine unit. FIG. 5 is an illustrative view showing a state of the stepped automatic transmission when the first speed clutch, the second speed clutch, the third speed clutch, and the fourth speed clutch are all disconnected. It is an illustration figure which shows the state of the stepped automatic transmission in case a gear position is 1st speed. It is an illustration figure which shows the state of a stepped automatic transmission in case a gear position is 2nd speed. It is an illustration figure which shows the state of the stepped automatic transmission in case a gear position is the 3rd speed. It is an illustration figure which shows the state of a stepped automatic transmission in case a gear position is 4th speed. It is sectional drawing solution figure which shows the conventional stepped automatic transmission.

  Embodiments of the present invention will be described below with reference to the drawings. Here, a case where the stepped automatic transmission of the present invention is applied to a scooter that is an example of a motorcycle will be described. In the embodiment of the present invention, front and rear, left and right, and top and bottom mean front and rear, left and right, and top and bottom with respect to a state where the driver is seated on the seat 40 of the scooter 10 toward the handle 16.

  Referring to FIG. 1, scooter 10 includes a vehicle body frame 12 and a vehicle body cover 14 provided so as to cover vehicle body frame 12. Although not shown in detail in FIG. 1 because it is hidden by the vehicle body cover 14, the front portion of the vehicle body frame 12 extends obliquely upward and forward, and the rear portion of the vehicle body frame 12 extends obliquely upward and backward. It extends. The vehicle body frame 12 has a head pipe (not shown) at its front end, and a steering shaft (not shown) is rotatably inserted into the head pipe. A handle 16 is attached to the upper end of the steering shaft, and a front fork 18 is attached to the lower end of the steering shaft. A front wheel 20 is rotatably supported on the lower end portion of the front fork 18 via an axle 22.

  A foot step 24 for a rider to put his / her foot on is provided at the lower end of the vehicle body cover 14 so as to extend in the left-right direction. A side stand 26 is attached to the body frame 12 behind the foot step 24 via an attachment portion 28. An engine unit 30 extending rearward is supported by a lower end portion of the vehicle body frame 12 via a pivot shaft 32 so as to be swingable behind the attachment portion 28. Specifically, an engine bracket 48 described later of the engine unit 30 is attached to the vehicle body frame 12 via the pivot shaft 32. As will be described later, the stepped automatic transmission 44 (see FIG. 2) is included in the engine unit 30.

  A rear wheel 34 is rotatably supported at the rear end portion of the engine unit 30 via an output shaft 36. A cushion unit 38 is provided between the rear portion (not shown) of the vehicle body frame 12 and the engine unit 30. A seat 40 for a rider to sit on is provided above the cushion unit 38 in the rear portion (not shown) of the vehicle body frame 12.

Hereinafter, the engine unit 30 will be described in detail.
FIG. 2 is an illustrative sectional view showing the internal structure of the engine unit 30, and FIG. 3 is an illustrative side view showing the engine unit 30.

  2 and 3, engine unit 30 includes an engine 42 (see FIG. 2), a stepped automatic transmission 44 (see FIG. 2), a casing 46, and an engine bracket 48 (see FIG. 3).

  Referring to FIG. 2, casing 46 includes a case thing main body 46a and a cover member 46b attached to the left end of casing main body 46a. The engine 42 is connected to the front end portion of the casing body 46a and extends forward, and a connecting rod 52 (only a part is shown in FIG. 2) provided in the cylinder body 50. Have A cylinder head 216 (see FIG. 7) described later is provided at the front end of the cylinder body 50. A piston 54 (see FIG. 12) described later is provided at the front end of the connecting rod 52 in the cylinder body 50. A crank chamber 56 is formed behind the cylinder body 50 in the casing 46.

  Referring to FIG. 2, stepped automatic transmission 44 includes a crankshaft 58. The crankshaft 58 is provided at the front end in the casing 46. The crankshaft 58 includes a pair of arm portions 58a and 58b disposed in the crank chamber 56, a crank pin 58c provided to connect the pair of arm portions 58a and 58b, a crank journal 58d extending leftward from the arm portion 58a, And a crank journal 58e extending rightward from the arm portion 58b. The rear end portion of the connecting rod 52 is connected to the crank pin 58c.

  The crankshaft 58 is connected via a bearing 60a provided at the right end of the crank journal 58d, a bearing 60b provided at the left end of the crank journal 58e, and a bearing 60c provided at the left end of the crank journal 58d. The casing 46 is rotatably supported. The crankshaft 58 rotates in the first direction based on the power generated by the engine 42. In the stepped automatic transmission 44, rotation of the crankshaft 58 in the first direction causes rotation shafts 140 and 248 and an output shaft 36 described later to rotate in the first direction, and rotation shafts 128 and 234 described later. 258 rotates in the second direction (the direction opposite to the first direction).

  The right end of the crank journal 58e is connected to the generator 62. The generator 62 generates power based on the rotation of the crank journal 58e.

  Referring to FIG. 4, crank journal 58d has a substantially cylindrical oil passage 58f extending in the right direction along the axial center from the left end portion, and a substantially cylindrical oil passage 58g extending in the radial direction from oil passage 58f. Have The oil passage 58f opens at the left end face of the crank journal 58d.

  2 and 4, the crank journal 58d is provided with a first clutch unit 64. The first clutch unit 64 has a clutch housing 66 provided coaxially with the crank journal 58d. Referring to FIG. 4, the clutch housing 66 has a hollow disc-like plate portion 66a extending in the radial direction of the crank journal 58d and a cylindrical portion 66b extending leftward from the outer peripheral edge of the plate portion 66a. A plurality of notches 66c are formed at equal intervals in the circumferential direction at the left end of the cylindrical portion 66b. A plurality (four in this embodiment) of annular friction disks 68 are attached to the left end of the cylindrical portion 66b. Specifically, each friction disk 68 has a plurality of convex portions 68a provided corresponding to the plurality of notches 66c on its outer peripheral edge, and each convex portion 68a is fitted into each notch 66c. Accordingly, the friction disk 68 is attached to the cylindrical portion 66b. The inner peripheral edge of the plate portion 66a is fixed to a gear 70 provided coaxially with the crank journal 58d. Thereby, the clutch housing 66 and the gear 70 rotate integrally.

  The gear 70 includes a hollow substantially disc-shaped main body portion 70a and a cylindrical portion 70b extending leftward from the main body portion 70a. Gear teeth 72 are integrally formed on the outer peripheral surface of the main body 70a. The cylindrical portion 70 b is provided inside the clutch housing 66. The gear 70 (main body portion 70a) is provided coaxially with the crank journal 58d via a cylindrical bush 74 and a cylindrical collar 76. The bush 74 is press-fitted into the gear 70 (main body portion 70a), and the collar 76 is fixed to the crank journal 58d. The bush 74 is provided to be rotatable with respect to the collar 76. As a result, the gear 70 and the clutch housing 66 can rotate relative to the crank journal 58d.

  A one-way clutch 80 is provided coaxially with the crank journal 58d so as to connect the crank journal 58d and the cylindrical portion 70b inside the cylindrical portion 70b. The one-way clutch 80 does not transmit the rotation of the crank journal 58d in the first direction from the crank shaft 58 to the gear 70 (clutch housing 66), and cranks the rotation of the gear 70 (clutch housing 66) in the first direction from the gear 70. This is transmitted to the journal 58d. Therefore, the one-way clutch 80 does not transmit the driving force generated by the engine 42 to the gear 70. When the crank journal 58d and the gear 70 (clutch housing 66) both rotate in the first direction and the rotation speed of the crank journal 58d is higher than the rotation speed of the gear 70 (clutch housing 66), the one-way clutch 80 is The rotation of the gear 70 (clutch housing 66) in the first direction is not transmitted to the crank journal 58d.

  On the left side of the one-way clutch 80, the crank journal 58d is provided with a centrifugal clutch portion 82 so as to rotate integrally with the crank journal 58d. The centrifugal clutch unit 82 includes a drive plate 84, a plurality of clutch weights 86 (only two are shown in FIG. 4), a friction material 88 provided on the outer peripheral surface of each clutch weight 86, and a plurality of clutch weights 86 connected to each other. A spring 90 (only one is shown in FIG. 4) is provided.

  The drive plate 84 is connected to the crankshaft 58 via a key 92 provided in the keyway 58 h of the crankshaft 58. Thereby, the crankshaft 58 and the drive plate 84 rotate integrally. The clutch weight 86 is attached to the drive plate 84 via a spring 90 so as to move in the radial direction of the drive plate 84 based on centrifugal force. In the centrifugal clutch portion 82, the centrifugal force acting on the clutch weight 86 increases as the rotational speed of the drive plate 84 (crank journal 58d) increases. As a result, the clutch weight 86 moves in the radial direction of the drive plate 84.

  Referring to FIG. 5, when the rotational speed of drive plate 84 (crankshaft 58) reaches a predetermined speed, friction material 88 comes into contact with cylindrical portion 66 b of clutch housing 66. As a result, the rotation of the crank journal 58d is transmitted to the clutch housing 66 via the centrifugal clutch portion 82. As a result, the clutch housing 66 and the gear 70 rotate in the first direction. In the stepped automatic transmission 44, the centrifugal clutch portion 82 and the clutch housing 66 function as the first speed clutch C1. Hereinafter, the state in which the clutch housing 66 and the friction material 88 are in contact is referred to as the first speed clutch C1 being connected, and the state in which the clutch housing 66 and the friction material 88 are not in contact is referred to as the first speed clutch C1. Is said to have been disconnected.

  Referring to FIG. 4, a cylindrical collar 94 and a hydraulic clutch portion 96 are provided on the left side of the centrifugal clutch portion 82 and coaxially with the crank journal 58d. The collar 94 has an oil passage 94a communicating with the oil passage 58g of the crank journal 58d and penetrating in the radial direction. The collar 94 is fixed to the crank journal 58d, and the hydraulic clutch portion 96 is provided to be rotatable with respect to the collar 94. Thereby, the hydraulic clutch part 96 can be rotated relative to the crank journal 58d.

  The hydraulic clutch unit 96 includes a clutch boss 98, a pressure plate 100, and a guide member 102. The clutch boss 98 has a cylindrical portion 104 extending in the left-right direction at the center thereof, a flange portion 106 extending in the radial direction of the cylindrical portion 104 from the left end portion of the cylindrical portion 104, and a flange portion extending from the right end portion of the flange portion 106. The plate portion 108 extends in the radial direction 106.

  The cylindrical portion 104 has an annular oil passage 104a formed on the inner peripheral surface thereof and communicating with the oil passage 94a of the collar 94, and a plurality of oil passages 104b penetrating from the oil passage 104a in a substantially radial direction.

  An annular mounting portion 108a is formed on the outer edge portion of the plate portion 108 so as to extend in the right direction. A plurality of notches 108b are formed in the mounting portion 108a at equal intervals in the circumferential direction, like the notches 66c of the clutch housing 66. A plurality (three in this embodiment) of annular clutch disks 110 are attached to the attachment portion 108a. Specifically, each clutch disk 110 has a plurality of convex portions 110a provided corresponding to the plurality of notches 108b on the inner periphery thereof, and each convex portion 110a is fitted into each notch 108b. Thus, the clutch disk 110 is attached to the attachment portion 108a. The plurality of friction disks 68 and the plurality of clutch disks 110 are alternately arranged.

  An annular stopper 112 is fixed to the right end of the outer peripheral surface of the cylindrical portion 104. The guide member 102 has a hollow substantially disk shape, and is fitted to the cylindrical portion 104 of the clutch boss 98 so that the movement in the right direction is restricted by the stopper 112.

  The pressure plate 100 is provided between the flange portion 106 and the plate portion 108 and the guide member 102 and is slidable with respect to the cylindrical portion 104. A substantially cylindrical second sliding portion 100b extending rightward from the outer edge of the portion 100a and slidable with respect to the guide member 102, and a flange-like shape extending from the second sliding portion 100b in the radial direction of the crankshaft 58. It has a pressing part 100c. The pressure plate 100 has a leak hole 100d penetrating in the left-right direction. The leak hole 100d communicates with a working chamber 116 described later.

  A plurality of springs 114 (only one is shown in FIG. 4) are provided between the first sliding portion 100a and the plate portion. The first sliding portion 100a is urged rightward by a plurality of springs 114. A space 116 (hereinafter referred to as a working chamber 116) communicating with the oil passage 104 b of the cylindrical portion 104 is formed between the first sliding portion 100 a and the guide member 102.

  A gear 118 is fitted to the flange portion 106. The gear 118 is fixed to the clutch boss 98 by a bolt 120. As a result, the clutch boss 98 and the gear 118 rotate integrally. A washer 122 is provided on the left side of the collar 94 and the flange portion 106 in the crank journal 58d, and a nut 124 is fixed on the left side of the washer 122 in the crank journal 58d. Thereby, the movement of the collar 94 and the clutch boss 98 in the left direction is restricted.

  The casing 46 has an oil passage 126 communicating with the left end portion of the oil passage 58f of the crank journal 58d. Hydraulic oil is pumped into the oil passage 126 by an oil pump 210 (see FIG. 7) described later. Referring to FIG. 5, in the first clutch unit 64, the hydraulic oil pressure-fed to the oil passage 126 passes through the oil passage 58f, the oil passage 58g, the oil passage 94a, the oil passage 104a, and the oil passage 104b. Flow into. Then, the pressure plate 100 is moved leftward by the hydraulic pressure of the hydraulic oil in the working chamber 116, and the plurality of friction disks 68 and the plurality of clutch disks 110 are pushed leftward by the pressing portion 100c. Thereby, the plurality of friction disks 68 and the plurality of clutch disks 110 are pressed against each other. As a result, the rotation of the clutch housing 66 is transmitted to the clutch boss 98 via the friction disk 68 and the clutch disk 110. As a result, the clutch boss 98 and the gear 118 rotate in the first direction. The hydraulic oil in the working chamber 116 flows out of the working chamber 116 through the leak hole 100d. Therefore, when the supply of the hydraulic oil to the working chamber 116 is stopped, the hydraulic oil in the working chamber 116 decreases, and the pressure plate 100 moves to the right due to the elastic force of the spring 114. As a result, the pressure contact state between the plurality of friction disks 68 and the plurality of clutch disks 110 is released, and transmission of rotation from the clutch housing 66 to the clutch boss 98 is interrupted.

  In the stepped automatic transmission 44 (see FIG. 2), the hydraulic clutch portion 96 and the clutch housing 66 function as the second speed clutch C2. Hereinafter, the state in which the plurality of friction disks 68 and the plurality of clutch disks 110 are in pressure contact is referred to as the second speed clutch C2 being connected, and the plurality of friction disks 68 and the plurality of clutch disks 110 are in pressure contact. The state in which the second speed clutch C2 is disengaged is said to be absent.

  Referring to FIGS. 2 and 3, a rotating shaft 128 is provided in parallel to the crank journal 58 d in the casing 46 and obliquely below the rear of the crank journal 58 d. Referring to FIG. 2, the right end of rotating shaft 128 is rotatably supported by casing 46 via bearing 130, and the left end of rotating shaft 128 rotates to casing 46 via bearing 132. Supported as possible.

  A gear 134 is provided on the left side of the bearing 130 coaxially with the rotating shaft 128 so as to mesh with the gear 70 (gear tooth 72). The gear 134 is provided on the rotating shaft 128 via a bearing 135 and a one-way clutch 136. The bearing 135 supports the gear 134 rotatably. The one-way clutch 136 does not transmit the rotation of the rotating shaft 128 in the second direction from the rotating shaft 128 to the gear 134 and transmits the rotation of the gear 134 in the second direction from the gear 134 to the rotating shaft 128. When the rotation shaft 128 and the gear 134 rotate in the second direction and the rotation speed of the rotation shaft 128 is larger than the rotation speed of the gear 134, the one-way clutch 136 rotates the gear 134 in the second direction. It is not transmitted to the rotating shaft 128.

  A gear 138 is fixed on the rotation shaft 128 on the right side of the bearing 132 so as to rotate integrally with the rotation shaft 128. With reference to FIGS. 2 and 3, the gear 138 meshes with the gear 118. Therefore, the rotation of the gear 118 is transmitted to the rotating shaft 128 via the gear 138. Thereby, the rotating shaft 128 rotates in the second direction.

  Referring to FIG. 2, in stepped automatic transmission 44, when only first speed clutch C1 is connected (when the gear position is first speed), rotation of crank journal 58d is a centrifugal clutch. It is transmitted to the gear 134 via the part 82 (see FIG. 5), the clutch housing 66 and the gear 70. Thereby, the gear 134 rotates in the second direction. As described above, since the one-way clutch 136 transmits the rotation of the gear 134 in the second direction to the rotation shaft 128, the rotation shaft 128 rotates in the second direction when the gear 134 rotates in the second direction.

  On the other hand, when both the first speed clutch C1 and the second speed clutch C2 are connected (when the gear position is the second speed or higher), the rotation of the crank journal 58d is transmitted to the gear 70 and the clutch housing. 66 and the hydraulic clutch 96 (see FIG. 5). Thereby, the gear 118 rotates in the first direction at the same rotational speed as the gear 70. Since the gear 138 meshes with the gear 118, the gear 138 rotates in the second direction when the gear 118 rotates in the first direction. Thereby, the rotating shaft 128 rotates in the second direction. Here, in the stepped automatic transmission 44, the gear ratio (reduction ratio) between the gear 118 and the gear 138 is set smaller than the gear ratio between the gear 70 and the gear 134. Therefore, the rotational speeds of the gear 138 and the rotary shaft 128 are faster than the rotational speed of the gear 134. As described above, when the rotation speed of the rotation shaft 128 is higher than the rotation speed of the gear 134, the one-way clutch 136 does not transmit the rotation of the gear 134 in the second direction to the rotation shaft 128. Therefore, when both the first speed clutch C1 and the second speed clutch C2 are connected (when the gear position is the second speed or higher), the gear 134 idles.

  With reference to FIGS. 2 and 3, a rotating shaft 140 is provided in parallel to the rotating shaft 128 on the rear obliquely upper side of the rotating shaft 128. Referring to FIGS. 2 and 6, the right end of rotating shaft 140 is rotatably supported by casing 46 via bearing 142, and the left end of rotating shaft 140 is casing via bearing 144. 46 is rotatably supported.

  Referring to FIG. 6, the rotating shaft 140 includes an oil passage 140 a extending from the right end portion to the substantially central portion along the axial center, an oil passage 140 b extending from the left end portion to the substantially central portion along the axial center, An annular oil passage 140c, 140d formed on the outer peripheral surface of the substantially central portion, an oil passage 140e connecting the oil passage 140a and the oil passage 140c, and an oil passage 140f connecting the oil passage 140b and the oil passage 140d are provided. .

  A gear 148 is provided on the left side of the rotating shaft 140 from the bearing 142 via a bush 146. The bush 146 is press-fitted into the gear 148 and is provided so as to be rotatable with respect to the rotating shaft 140.

  A second clutch unit 150 is provided on the left side of the rotation shaft 140 from the gear 148. The second clutch unit 150 includes substantially cylindrical clutch housings 152 and 154 provided to face each other. A plurality of friction disks 156 are attached to the left end of the clutch housing 152, and a plurality of friction disks 158 are attached to the right end of the clutch housing 154. The friction disks 156 and 158 are attached to the clutch housings 152 and 154 with the same configuration as the friction disk 68 of FIG.

  The clutch housing 152 is fixed to the gear 148 by a bolt 160. Thereby, the clutch housing 152 and the gear 148 rotate integrally. The clutch housing 154 is fixed to a gear 188 described later by a bolt 162. Thereby, the clutch housing 154 and the gear 188 rotate integrally.

  An annular guide member 164 having an I-shaped cross section is fixed to the rotary shaft 140 at an intermediate portion between the clutch housing 152 and the clutch housing 154. A hollow substantially disk-shaped pressure plate 166 is provided between the clutch housing 152 and the guide member 164. The pressure plate 166 is slidably provided on the guide member 164. Similarly, a hollow substantially disk-shaped pressure plate 168 is provided between the clutch housing 154 and the guide member 164. The pressure plate 168 is slidably provided on the guide member 164. A working chamber 170 is formed between the guide member 164 and the pressure plate 166, and a working chamber 172 is formed between the guide member 164 and the pressure plate 168. The guide member 164 includes an oil passage 164a that connects the oil passage 140c and the working chamber 170, and an oil passage 164b that connects the oil passage 140d and the working chamber 172. The pressure plate 166 has a leak hole 166a communicating with the working chamber 170 and penetrating in the left-right direction, and the pressure plate 168 has a leak hole 168a communicating with the working chamber 172 and penetrating in the left-right direction.

  A clutch boss 174 is fixed to the rotating shaft 140 between the pressure plate 166 and the clutch housing 152 so as to rotate integrally with the rotating shaft 140. A plurality of clutch disks 176 are attached to the clutch boss 174. The clutch disk 176 is attached to the clutch boss 174 with the same configuration as the clutch disk 110 (see FIG. 4). The plurality of friction disks 156 attached to the clutch housing 152 and the plurality of clutch disks 176 attached to the clutch boss 174 are alternately arranged. A plurality of springs 178 (only one is shown in FIG. 6) are provided between the pressure plate 166 and the clutch boss 174. The pressure plate 166 is biased leftward by a plurality of springs 178.

  A clutch boss 180 is fixed to the rotary shaft 140 so as to rotate integrally with the rotary shaft 140 between the pressure plate 168 and the clutch housing 154. A plurality of clutch disks 182 are attached to the clutch boss 180. The clutch disk 182 is attached to the clutch boss 180 with the same configuration as the clutch disk 110 (see FIG. 4). The plurality of friction disks 158 attached to the clutch housing 154 and the plurality of clutch disks 182 attached to the clutch boss 180 are alternately arranged. A plurality of springs 184 (only one is shown in FIG. 6) are provided between the pressure plate 168 and the clutch boss 180. The pressure plate 168 is urged rightward by a plurality of springs 184.

  On the left side of the clutch housing 154, the rotary shaft 140 is provided with a gear 188 via a bush 186. The bush 186 is press-fitted into the gear 188 and is provided to be rotatable with respect to the rotating shaft 140.

  A gear 190 is fixed to the rotating shaft 140 between the bush 186 and the bearing 144 so as to rotate integrally with the rotating shaft 140. The gear 190 includes a main body 190a where gear teeth are formed and an annular gear attachment 190b that protrudes rightward from the main body 190. A gear 192 is fixed to the gear mounting portion 190b so as to rotate integrally with the gear 190.

  Referring to FIG. 2, gear 192 meshes with gear 138. Therefore, the rotation of the gear 138 is transmitted to the rotating shaft 140 via the gear 192 and the gear 190. Thereby, the rotating shaft 140 rotates in the first direction.

  Referring to FIGS. 6 and 7, casing 46 (see FIG. 6) has an oil passage 194 that communicates with an end portion on the right side of oil passage 140 a of rotating shaft 140 and an end portion on the left side of oil passage 140 b of rotating shaft 140. The oil passage 196 communicates with the oil passage 126, the oil passage 198 communicates with the oil passages 126, 194, and 196 via a valve 220, which will be described later, and the oil passages 200 and 202 branched from the oil passage 198 (see FIG. 7).

  Referring to FIG. 7, oil passage 198 communicates with an oil passage (not shown) of rotating shaft 234 (see FIG. 2), which will be described later, through oil passage 204. A relief valve 206 is connected to the oil passage 200. The relief valve 206 prevents the hydraulic oil pressure in the oil passage 200 from exceeding a predetermined height. Oil passage 200 is connected to strainer 212 via oil cleaner 208, oil passage 209, and oil pump 210. The oil pump 210 is connected to the crankshaft 58 (see FIG. 2) via a connecting mechanism (not shown), for example, and is driven by the rotation transmitted from the crankshaft 58. Accordingly, the oil pump 210 is driven when the engine 42 is operated. The oil cleaner 208 purifies the hydraulic oil fed by the oil pump 210. The strainer 212 is immersed in the hydraulic oil stored in the oil pan 214. The oil pan 214 is provided at the bottom of the casing 46 (see FIG. 2) so as to be positioned below the crankshaft 58 (see FIG. 2), the rotating shaft 128 (see FIG. 2), and the rotating shaft 140 (see FIG. 2). ing. The oil passage 202 is connected to an oil passage (not shown) of the cylinder head 216 of the engine 42 (see FIG. 2) and communicates with an oil passage (not shown) of the crank journal 58e via the oil passage 218. ing.

  Referring to FIG. 6, the valve 220 has a substantially cylindrical shape and is rotatably provided on the casing 46. The valve 220 has internal passages 220a, 220b, and 220c that penetrate in the radial direction thereof. A motor 222 is connected to the valve 220. The valve 220 is rotated by a motor 222. The motor 222 is fixed to the casing 46, for example. The internal passage 220 a connects and disconnects the oil passage 126 and the oil passage 198 according to the rotation angle of the valve 220. The internal passage 220 b connects and disconnects the oil passage 194 and the oil passage 198 according to the rotation angle of the valve 220. The internal passage 220 c connects and disconnects the oil passage 196 and the oil passage 198 according to the rotation angle of the valve 220.

  The motor 222 is electrically connected to an ECU (electronic control unit) 224. The ECU 224 is attached to the vehicle body frame 12 (see FIG. 1), for example. ECU 224 is electrically connected to potentiometer 226, vehicle speed sensor 228, throttle opening sensor 230, and memory 232. The potentiometer 226 detects the rotation angle of the valve 220 and outputs a signal corresponding to the detected rotation angle to the ECU 224. The potentiometer 226 is provided in the valve 220, for example. Referring to FIG. 2, vehicle speed sensor 228 is provided at the rear end of casing 46. The vehicle speed sensor 228 detects the rotational speed of the output shaft 36 and calculates the vehicle speed of the scooter 10 based on the detected rotational speed of the output shaft 36. Further, the vehicle speed sensor 228 outputs a signal corresponding to the calculated rotation speed to the ECU 224. Referring to FIG. 6, throttle opening sensor 230 detects the opening (throttle opening) of a throttle valve (not shown) of engine 42 (see FIG. 2), and a signal corresponding to the detected throttle opening. Is output to the ECU 224. The memory 232 stores data indicating the relationship between the vehicle speed of the scooter 10, the throttle opening, and the gear position of the stepped automatic transmission 44. The memory 232 is attached to the vehicle body frame 12 (see FIG. 1) integrally with the ECU 224, for example.

  The ECU 224 determines an appropriate gear position of the stepped automatic transmission 44 based on the signals given from the vehicle speed sensor 228 and the throttle opening sensor 230 and the above-described data stored in the memory 232. Then, the ECU 224 drives the motor 222 based on the determined gear position, and rotates the valve 220 by a predetermined angle. Specifically, ECU 224 rotates valve 220 so that any of oil passage 126, oil passage 194, and oil passage 196 is connected to oil passage 198. As a result, the hydraulic oil pumped from the oil pan 214 to the oil passage 198 by the oil pump 210 can be selectively supplied to the oil passage 126, the oil passage 194 and the oil passage 196. The ECU 224 performs feedback control of the motor 222 based on a signal given from the potentiometer 226.

  Referring to FIG. 6, in the second clutch unit 150, the hydraulic oil pressure-fed to the oil passage 194 by the oil pump 210 (see FIG. 7) It flows into the working chamber 170 through 164a. Accordingly, referring to FIG. 8, the pressure plate 166 moves in the right direction, and the plurality of friction disks 156 and the plurality of clutch disks 176 are pushed rightward by the pressure plate 166. As a result, the plurality of friction disks 156 and the plurality of clutch disks 176 are pressed against each other, and the rotation of the rotating shaft 140 is transmitted to the clutch housing 152 via the clutch boss 174, the clutch disk 176, and the friction disk 156. As a result, the clutch housing 152 and the gear 148 rotate in the first direction. The hydraulic oil in the working chamber 170 flows out from the working chamber 170 through the leak hole 166a. Accordingly, when the supply of the hydraulic oil to the working chamber 170 is stopped, the hydraulic oil in the working chamber 170 is reduced, and the pressure plate 166 moves to the left by the elastic force of the spring 178. Accordingly, the pressure contact state between the plurality of friction disks 156 and the plurality of clutch disks 176 is released, and transmission of rotation from the rotating shaft 140 to the clutch housing 152 and the gear 148 is blocked.

  In the stepped automatic transmission 44 (see FIG. 2), the clutch housing 152, the plurality of friction disks 156, the pressure plate 166, the clutch boss 174, the plurality of clutch disks 176, and the plurality of springs 178 serve as the third-speed clutch C3. It is functioning. Hereinafter, the state in which the plurality of friction disks 156 and the plurality of clutch disks 176 are in pressure contact is referred to as the third speed clutch C3 being connected, and the plurality of friction disks 156 and the plurality of clutch disks 176 are in pressure contact. The state where there is no state is that the third speed clutch C3 is disengaged.

  Referring to FIG. 6, in second clutch unit 150, the hydraulic oil pressure-fed to oil passage 196 by oil pump 210 (see FIG. 7) is oil passage 140b, oil passage 140f, oil passage 140d, and oil passage. It flows into the working chamber 172 via 164b. 9, the pressure plate 168 moves leftward, and the pressure plates 168 push the plurality of friction disks 158 and the plurality of clutch disks 182 leftward. As a result, the plurality of friction disks 158 and the plurality of clutch disks 182 are pressed against each other, and the rotation of the rotating shaft 140 is transmitted to the clutch housing 154 via the clutch boss 180, the clutch disk 182 and the friction disk 158. As a result, the clutch housing 154 and the gear 188 rotate in the first direction. Note that the hydraulic oil in the working chamber 172 flows out of the working chamber 172 through the leak hole 168a. Therefore, when the supply of the hydraulic oil to the working chamber 172 is stopped, the hydraulic oil in the working chamber 172 decreases, and the pressure plate 168 moves rightward by the elastic force of the spring 184. Accordingly, the pressure contact state between the plurality of friction disks 158 and the plurality of clutch disks 182 is released, and transmission of rotation from the rotating shaft 140 to the clutch housing 154 and the gear 188 is blocked.

  In the stepped automatic transmission 44 (see FIG. 2), a clutch housing 154, a plurality of friction disks 158, a pressure plate 168, a clutch boss 180. The plurality of clutch disks 182 and the plurality of springs 184 function as the fourth speed clutch C4. Hereinafter, the state in which the plurality of friction disks 158 and the plurality of clutch disks 182 are in pressure contact is referred to as the four-speed clutch C4 being connected, and the plurality of friction disks 158 and the plurality of clutch disks 182 are in pressure contact. The state where there is no state is that the fourth speed clutch C4 is disengaged.

  As described above, in the stepped automatic transmission 44, hydraulic oil is selectively supplied to the oil passage 126, the oil passage 194, and the oil passage 196 according to the traveling state (vehicle speed and throttle opening) of the scooter 10. Is done. Thereby, the second speed clutch C2, the third speed clutch C3 and the fourth speed clutch C4 are selectively connected and disconnected, and the stepped automatic transmission 44 is set to an appropriate gear position. Note that the second speed clutch C2 (see FIG. 5) is connected by hydraulically feeding hydraulic oil to the oil passage 126 as described above.

  With reference to FIGS. 2 and 3, a rotating shaft 234 is provided in parallel with the rotating shaft 140 in the casing 46 obliquely below and behind the rotating shaft 140. Referring to FIG. 2, the right end of rotating shaft 234 is rotatably supported by casing 46 via bearing 236, and the left end of rotating shaft 234 rotates to casing 46 via bearing 238. Supported as possible.

  The rotating shaft 234 has gear teeth 234a on the outer peripheral surface of a substantially central portion in the left-right direction. A gear 240 is attached between the gear teeth 234 a and the bearing 236 on the rotating shaft 234 so as to rotate integrally with the rotating shaft 234. The gear 240 is in mesh with the gear 148. Therefore, referring to FIGS. 2 and 8, when the third speed clutch C3 is connected, the rotation of the rotary shaft 140 is caused by the clutch boss 174 (see FIG. 8) and the clutch disk 176 (see FIG. 8). , The friction disk 156 (see FIG. 8), the clutch housing 152 (see FIG. 8), the gear 148 and the gear 240 (see FIG. 2) are transmitted to the rotary shaft 234 (see FIG. 2). Thereby, the rotating shaft 234 rotates in the second direction.

  Referring to FIG. 2, gear 242 is fixed to the left side of gear shaft 234 on rotation shaft 234 so as to rotate integrally with rotation shaft 234. Gear 242 meshes with gear 188. Therefore, referring to FIGS. 2 and 9, when the fourth speed clutch C4 is connected, the rotation shaft 140 is rotated by the clutch boss 180 (see FIG. 9) and the clutch disk 182 (see FIG. 9). , The friction disk 158 (see FIG. 9), the clutch housing 154 (see FIG. 9), the gear 188 and the gear 242 (see FIG. 2) are transmitted to the rotating shaft 234 (see FIG. 2). Thereby, the rotating shaft 234 rotates in the second direction. Referring to FIG. 8, when the third speed clutch C3 is connected, the fourth speed clutch C4 is not connected. Similarly, referring to FIG. 9, when the fourth speed clutch C4 is connected, the third speed clutch C3 is not connected.

  Referring to FIG. 2, gear 244 is provided between gear 242 and bearing 238 on rotating shaft 234 so as to mesh with gear 190. The gear 244 is connected to the rotating shaft 234 via a bearing 245 and a one-way clutch 246. The bearing 245 supports the gear 244 to be rotatable. The one-way clutch 246 does not transmit the rotation of the rotation shaft 234 in the second direction from the rotation shaft 234 to the gear 244 and transmits the rotation of the gear 244 in the second direction from the gear 244 to the rotation shaft 234. When both the rotation shaft 234 and the gear 244 rotate in the second direction and the rotation speed of the rotation shaft 234 is larger than the rotation speed of the gear 244, the one-way clutch 246 rotates the gear 244 in the second direction. It is not transmitted to the rotating shaft 234.

  In the stepped automatic transmission 44, when both the third speed clutch C3 and the fourth speed clutch C4 are disengaged (when the gear position is the first speed or the second speed), the rotation of the gear 138 causes the gear to rotate. 192 and the gear 190 are transmitted to the gear 244. Thereby, the gear 244 rotates in the second direction. As described above, the one-way clutch 246 transmits the rotation of the gear 244 in the second direction to the rotation shaft 234, so that the rotation shaft 234 rotates in the second direction when the gear 244 rotates in the second direction.

  When the third speed clutch C3 is connected and the fourth speed clutch C4 is disconnected (when the gear position is the third speed), the rotation of the gear 138 is transmitted to the gear 244 via the gear 192 and the gear 190. At the same time, it is transmitted to the gear 240 via the gear 192, the gear 190, the rotating shaft 140, the third speed clutch C 3 and the gear 148. Thereby, the gear 240 and the rotating shaft 234 rotate in the second direction. Here, in the stepped automatic transmission 44, the gear ratio (reduction ratio) between the gear 148 and the gear 240 is set smaller than the gear ratio between the gear 190 and the gear 244. Therefore, the rotation speeds of the gear 240 and the rotation shaft 234 are faster than the rotation speed of the gear 244. As described above, when the rotation speed of the rotation shaft 234 is higher than the rotation speed of the gear 244, the one-way clutch 246 does not transmit the rotation of the gear 244 in the second direction to the rotation shaft 234. Therefore, when the gear position of the stepped automatic transmission 44 is the third speed, the gear 244 rotates idly.

  When the fourth speed clutch C4 is connected and the third speed clutch C3 is disconnected (when the gear position is the fourth speed), the rotation of the gear 138 is transmitted to the gear 244 via the gear 192 and the gear 190. At the same time, it is transmitted to the gear 242 via the gear 192, the gear 190, the rotating shaft 140, the fourth speed clutch C 4 and the gear 188. Thereby, the gear 242 and the rotating shaft 234 rotate in the second direction. Here, in the stepped automatic transmission 44, the gear ratio (reduction ratio) between the gear 188 and the gear 242 is set smaller than the gear ratio between the gear 190 and the gear 244. Therefore, the rotation speeds of the gear 242 and the rotation shaft 234 are faster than the rotation speed of the gear 244. As described above, when the rotation speed of the rotation shaft 234 is higher than the rotation speed of the gear 244, the one-way clutch 246 does not transmit the rotation of the gear 244 in the second direction to the rotation shaft 234. Therefore, when the gear position of the stepped automatic transmission 44 is the fourth speed, the gear 244 idles. The gear ratio (reduction ratio) between the gear 188 and the gear 242 is set smaller than the gear ratio between the gear 148 and the gear 240. Therefore, the rotational speed of the rotary shaft 234 when the fourth-speed clutch C4 is connected is higher than the rotational speed of the rotary shaft 234 when the third-speed clutch C3 is connected.

  Referring to FIGS. 2 and 3, a rotation shaft 248 is provided in parallel with the rotation shaft 234 behind the rotation shaft 234 in the casing 46. Referring to FIG. 2, rotating shaft 248 is rotatably supported by casing 46 via bearings 250 and 252. A gear 254 and a gear 256 are attached to the rotation shaft 248 so as to rotate integrally with the rotation shaft 248. The gear 254 meshes with the gear teeth 234a of the rotating shaft 234. Therefore, the rotation of the rotation shaft 234 is transmitted to the rotation shaft 248 via the gear 254. Thereby, the rotating shaft 248 rotates in the first direction.

  Referring to FIGS. 2 and 3, a rotating shaft 258 is provided in parallel with the rotating shaft 248 behind the rotating shaft 248 in the casing 46. Referring to FIG. 2, rotating shaft 258 is rotatably supported by casing 46 via bearings 260 and 262. A gear 264 is attached to the rotation shaft 258 so as to rotate integrally with the rotation shaft 258. The gear 264 meshes with the gear 256. Therefore, the rotation of the rotation shaft 248 is transmitted to the rotation shaft 258 via the gear 256 and the gear 264. Thereby, the rotating shaft 258 rotates in the second direction.

  Referring to FIGS. 2 and 3, output shaft 36 is provided in parallel to rotating shaft 258 behind rotating shaft 258. Referring to FIG. 2, output shaft 36 is rotatably supported by casing 46 via bearing 266 and bearing 268. The output shaft 36 is provided so as to protrude rightward from the casing 46. A gear 270 is attached to the output shaft 36 in the casing 46 so as to rotate integrally with the output shaft 36. A rear wheel 34 (see FIG. 1) is attached to the right end (not shown) of the output shaft 36 so as to rotate integrally with the output shaft 36. The gear 270 meshes with the gear 264. Therefore, the rotation of the rotation shaft 258 is transmitted to the output shaft 36 via the gear 264 and the gear 270. Thereby, the output shaft 36 and the rear wheel 34 (see FIG. 1) rotate in the first direction. As a result, the scooter 10 (see FIG. 1) moves forward.

  Referring to FIGS. 10 and 11, a gear 272 is attached to the crank journal 58d on the right side of the gear 70 via a one-way clutch. In the casing 46, a fixed shaft 274 is provided obliquely above and forward of the crank journal 58d. The fixed shaft 274 is fixed to the casing 46. The fixed shaft 274 is provided with a gear 276 that is rotatable with respect to the fixed shaft 274. The gear 276 includes a first gear portion 276a provided to mesh with the gear 272 and a second gear portion 276b having a larger diameter than the first gear portion 276a.

  A cell motor 278 is provided so as to be supported by the casing 46 obliquely in front of the fixed shaft 274. The cell motor 278 has a rotating shaft 280 having gear teeth formed on the outer peripheral surface. The rotation shaft 280 meshes with the second gear portion 276b of the gear 276.

  In such a configuration, when the cell motor 278 is driven, the rotation of the rotating shaft 280 is transmitted to the crank journal 58d via the gear 276 and the gear 272. As a result, the crankshaft 58 (see FIG. 10) rotates and the engine 42 is started.

  Referring to FIGS. 10 and 11, a gear 282 is attached to the crank journal 58d on the right side of the gear 272 so as to rotate integrally with the crank journal 58d. In the casing 46, a balancer shaft 284 is rotatably provided behind and obliquely above the crank journal 58d. A gear 286 is fixed to the left end portion of the balancer shaft 284 so as to rotate integrally with the balancer shaft 284. On the right side of the balancer shaft 284 with respect to the gear 286, a gear 288 is fixed so as to rotate integrally with the balancer shaft 284. The gear 288 is in mesh with the gear 282.

  A rotating shaft 290 is rotatably provided above the balancer shaft 284 in the casing 46. A gear 292 is provided at the right end of the rotating shaft 290 so as to mesh with the gear 286. Referring to FIG. 10, a ratchet member 294 is provided on the left side of the rotation shaft 290 from the gear 292. The ratchet member 294 is provided so as to be movable in the axial direction of the rotation shaft 290. The ratchet member 294 does not mesh with the gear 292 when a kick pedal 302 described later is not operated. Therefore, even if the gear 292 rotates based on the rotation transmitted from the crankshaft 58, the rotation of the gear 292 is not transmitted to the rotating shaft 290. Thereby, it is possible to prevent the rotation shaft 290 from rotating when the engine 42 is operated. When the rider operates a kick pedal 302 described later, the rotation shaft 290 rotates and the ratchet member 294 moves in the right direction. Thereby, the ratchet member 294 and the gear 292 are engaged with each other, and the rotation of the rotating shaft 290 is transmitted to the gear 292. A gear 296 is fixed to the left end of the rotation shaft 290 so as to rotate integrally with the rotation shaft 290.

  Referring to FIGS. 10 and 11, kick shaft 298 is rotatably provided so as to be supported by casing 46 below rotary shaft 290. A substantially fan-shaped gear 300 is fixed to the right end of the kick shaft 298 so as to rotate integrally with the kick shaft 298. Referring to FIG. 10, a kick pedal 302 is attached to the left end portion of kick shaft 298. A torsion coil spring 304 is provided in the casing 46 coaxially with the kick shaft 298. One end of the torsion coil spring 304 is connected to the casing 46, and the other end is connected to the gear 300. When the kick shaft 298 rotates in one direction by the rider operating the kick pedal 302, the torsion coil spring 304 gives the gear 300 and the kick shaft 298 rotation in the opposite direction.

  In such a configuration, when the rider operates the kick pedal 302, the kick shaft 298 rotates in one direction. The rotation of the kick shaft 298 is transmitted to the crank journal 58d via the gear 300, the gear 296, the rotation shaft 290, the ratchet member 294, the gear 292, the gear 286, the balancer shaft 284, the gear 288, and the gear 282. Thereby, the crankshaft 58 rotates and the engine 42 is started. Thus, in the engine unit 30, the engine 42 can be started by using either the cell motor 278 or the kick pedal 302.

  Next, the operation of the stepped automatic transmission 44 will be described in detail with reference to FIGS. 6 and 7, Table 1 below, and FIGS. In FIGS. 12 to 16 used in the following description, the configuration of the stepped automatic transmission 44 is schematically shown. FIG. 12 shows a state where the first speed clutch C1, the second speed clutch C2, the third speed clutch C3, and the fourth speed clutch C4 are all disconnected. FIG. 13 shows a state where the gear position of the stepped automatic transmission 44 is in the first speed, that is, only the first speed clutch C1 is connected. FIG. 14 shows a state in which the gear position of the stepped automatic transmission 44 is in the second speed, that is, only the first speed clutch C1 and the second speed clutch C2 are connected. FIG. 15 shows a state in which the gear position of the stepped automatic transmission 44 is in the third speed, that is, a state in which the first speed clutch C1, the second speed clutch C2, and the third speed clutch C3 are connected. FIG. 16 shows a state in which the gear position of the stepped automatic transmission 44 is in the fourth speed, that is, a state in which the first speed clutch C1, the second speed clutch C2, and the fourth speed clutch C4 are connected. Table 1 also shows the relationship between the gear position of the stepped automatic transmission 44, the valve 220, the first speed clutch C1, the second speed clutch C2, the third speed clutch C3, and the fourth speed clutch C4. Yes.

First, the state of the stepped automatic transmission 44 when the engine 42 is stopped will be described.
Referring to FIG. 7, when engine 42 (see FIG. 2) is stopped, oil pump 210 is in a stopped state. In this case, hydraulic fluid is not supplied to the working chamber 116 of the second speed clutch C2 and the working chamber 170 of the third speed clutch C3 and the working chamber 172 of the fourth speed clutch C4. Accordingly, referring to FIG. 12, second-speed clutch C2, third-speed clutch C3 and fourth-speed clutch C4 are disengaged. Further, since the crankshaft 58 (see FIG. 2) is not rotating when the engine 42 is stopped, the first speed clutch C1 configured as a centrifugal clutch is also in a disconnected state. Referring to FIG. 7, when engine 42 (see FIG. 2) is stopped, internal passages 220a, 220b, and 220c of valve 220 are closed. Therefore, the oil passage 126, the oil passage 194 and the oil passage 196 are not connected to the oil passage 198.

Next, the operation of the stepped automatic transmission 44 when the engine 42 is operating will be described.
As described above, the oil pump 210 is driven by the operation of the engine 42 (see FIG. 2). Here, when the engine 42 is started (or idling), the vehicle speed and the throttle opening of the scooter 10 do not satisfy predetermined conditions, so the ECU 224 (see FIG. 6) opens the internal passages 220a, 220b, and 220c. do not do. Therefore, hydraulic fluid is not supplied to the working chamber 116 of the second speed clutch C2 and the working chamber 170 of the third speed clutch C3 and the working chamber 172 of the fourth speed clutch C4. Therefore, as shown in Table 1, when the engine 42 is started (during idling), the disengaged state of the second speed clutch C2, the third speed clutch C3, and the fourth speed clutch C4 is maintained. Referring to FIG. 7, the hydraulic oil pumped from the strainer 212 by the oil pump 210 is supplied to the cylinder head 216 via the oil passage 209, the oil cleaner 208, the oil passage 200, and the oil passage 202, and the oil passage 198 and the oil passage 204 are supplied to the rotary shaft 234. A part of the hydraulic oil in the oil passage 202 is supplied to the crank journal 58 e through the oil passage 218. Referring to FIG. 12, when engine 42 is started (idling), the rotational speed of crankshaft 58 does not reach a predetermined speed, and therefore, first-speed clutch C1 is not connected. Therefore, the rotation of the crankshaft 58 is not transmitted to the output shaft 36.

  Next, referring to FIG. 13, when the rotational speed of the crankshaft 58 reaches a predetermined speed, the first-speed clutch C1 is connected, and the gear position of the stepped automatic transmission 44 is set to the first speed. The At this time, referring to Table 1, FIG. 6, and FIG. 7, since the internal passages 220a, 220b, and 220c of the valve 220 are closed, the working chamber 116 of the second speed clutch C2 (see FIG. 7), third speed The hydraulic oil is not supplied to the working chamber 170 of the clutch C3 and the working chamber 172 of the fourth speed clutch C4. That is, the disconnected state of the second speed clutch C2, the third speed clutch C3, and the fourth speed clutch C4 is maintained. Referring to FIG. 13, when the gear position of stepped automatic transmission 44 is the first speed, rotation of crankshaft 58 is performed by first-speed clutch C1, gear 70, gear 134, one-way clutch 136, rotating shaft. 128, gear 138, gear 192, gear 190, gear 244, one-way clutch 246, rotating shaft 234, gear tooth 234 a, gear 254, rotating shaft 248, gear 256, gear 264, and gear 270 to be transmitted to the output shaft 36. The Thereby, the rear wheel 34 (FIG. 1) is driven.

  Next, referring to FIG. 6, ECU 224 determines that the vehicle speed and throttle opening of scooter 10 are 1 based on the output signal of vehicle speed sensor 228, the output signal of throttle opening sensor 230 and the data stored in memory 232. It is determined whether or not the condition for shifting from the second speed to the second speed is satisfied. When the vehicle speed and the throttle opening satisfy the conditions for shifting from the first speed to the second speed, the ECU 224 controls the motor 222 to rotate the valve 220 by a predetermined angle. Specifically, referring to FIGS. 6 and 7, ECU 224 (FIG. 6) opens internal passage 220 a by rotating valve 220, and causes oil passage 126 and oil passage 198 to communicate with each other. Thereby, referring to FIG. 7, the hydraulic oil in oil passage 198 is supplied to working chamber 116 via internal passage 220a, oil passage 126, and oil passage 58f. As a result, the second speed clutch C2 is connected and the gear position of the stepped automatic transmission 44 is set to the second speed. At this time, referring to Table 1, FIG. 6 and FIG. 7, since the internal passages 220b and 220c of the valve 220 are closed, the working chamber 170 of the third speed clutch C3 and the working chamber 172 of the fourth speed clutch C4 are closed. No hydraulic oil is supplied. That is, the disconnected state of the third speed clutch C3 and the fourth speed clutch C4 is maintained.

  Referring to FIG. 14, as described above, when the gear position of the stepped automatic transmission 44 is the second speed (when both the first speed clutch C1 and the second speed clutch C2 are connected), The one-way clutch 136 does not transmit the rotation of the gear 134 to the rotating shaft 128. Therefore, the rotation of the crankshaft 58 includes the centrifugal clutch portion 82, the clutch housing 66, the hydraulic clutch portion 96, the gear 118, the gear 138, the gear 192, the gear 190, the gear 244, the one-way clutch 246, the rotating shaft 234, and the gear teeth. 234a, the gear 254, the rotating shaft 248, the gear 256, the gear 264, and the gear 270 are transmitted to the output shaft 36. Thereby, the rear wheel 34 (FIG. 1) is driven.

  Next, referring to FIG. 6, ECU 224 determines that the vehicle speed and throttle opening of scooter 10 are 2 based on the output signal of vehicle speed sensor 228, the output signal of throttle opening sensor 230, and the data stored in memory 232. It is determined whether or not the condition for shifting from the third speed to the third speed is satisfied. When the vehicle speed and the throttle opening satisfy the conditions for shifting from the second speed to the third speed, the ECU 224 controls the motor 222 to rotate the valve 220 by a predetermined angle. Specifically, referring to FIGS. 6 and 7, ECU 224 (FIG. 6) opens internal passage 220 b by rotating valve 220, and causes oil passage 194 and oil passage 198 to communicate with each other. Thus, referring to FIG. 7, the hydraulic oil in oil passage 198 is supplied to working chamber 170 of third-speed clutch C3 via internal passage 220b, oil passage 194, and oil passage 140a. As a result, the third speed clutch C3 is connected, and the gear position of the stepped automatic transmission 44 is set to the third speed. At this time, referring to Table 1, FIG. 6 and FIG. 7, since the internal passage 220c of the valve 220 is closed, hydraulic fluid is not supplied to the working chamber 172 of the fourth speed clutch C4. Therefore, the disconnected state of the fourth speed clutch C4 is maintained. Further, since the opening of the internal passage 220a of the valve 220 is maintained, the connected state of the second speed clutch C2 (see FIG. 7) is maintained.

  Referring to FIG. 15, as described above, when the gear position of stepped automatic transmission 44 is the third speed, one-way clutch 246 does not transmit the rotation of gear 244 to rotating shaft 234. Therefore, the rotation of the crankshaft 58 is caused by the centrifugal clutch portion 82, the clutch housing 66, the hydraulic clutch portion 96, the gear 118, the gear 138, the gear 192, the gear 190, the rotating shaft 140, the third speed clutch C3, the gear 148, It is transmitted to the output shaft 36 via the gear 240, the rotation shaft 234, the gear teeth 234 a, the gear 254, the rotation shaft 248, the gear 256, the gear 264 and the gear 270. Thereby, the rear wheel 34 (FIG. 1) is driven.

  Next, referring to FIG. 6, ECU 224 determines that the vehicle speed and throttle opening of scooter 10 are 3 based on the output signal of vehicle speed sensor 228, the output signal of throttle opening sensor 230, and the data stored in memory 232. It is determined whether or not the conditions for shifting from the fourth speed to the fourth speed are satisfied. When the vehicle speed and the throttle opening satisfy the conditions for shifting from the third speed to the fourth speed, the ECU 224 controls the motor 222 to rotate the valve 220 by a predetermined angle. Specifically, referring to FIGS. 6 and 7, ECU 224 (FIG. 6) rotates valve 220 to close internal passage 220b and open internal passage 220c. As a result, the oil passage 194 and the oil passage 198 are blocked, and the oil passage 196 and the oil passage 198 are communicated. As a result, referring to FIG. 7, the supply of the working oil to the working chamber 170 of the third speed clutch C3 is stopped, and the working oil in the oil passage 198 flows into the internal passage 220c, the oil passage 196, and the oil passage. 140b is supplied to the working chamber 172 of the fourth speed clutch C4. As a result, the third speed clutch C3 is disconnected and the fourth speed clutch C4 is connected, and the gear position of the stepped automatic transmission 44 is set to the fourth speed. At this time, referring to Table 1, FIG. 6 and FIG. 7, since the internal passage 220a of the valve 220 is opened, the connected state of the second speed clutch C2 is maintained.

  Referring to FIG. 16, as described above, when the gear position of stepped automatic transmission 44 is the fourth speed, one-way clutch 246 does not transmit the rotation of gear 244 to rotating shaft 234. Therefore, the rotation of the crankshaft 58 includes the centrifugal clutch portion 82, the clutch housing 66, the hydraulic clutch portion 96, the gear 118, the gear 138, the gear 192, the gear 190, the rotating shaft 140, the fourth speed clutch C4, the gear 188, It is transmitted to the output shaft 36 via the gear 242, the rotating shaft 234, the gear teeth 234a, the gear 254, the rotating shaft 248, the gear 256, the gear 264, and the gear 270. Thereby, the rear wheel 34 (FIG. 1) is driven.

  When shifting the gear position of the stepped automatic transmission 44 from the fourth speed to the third speed, the third speed to the second speed, or the second speed to the first speed, the ECU 224 maintains the relationship shown in Table 1. As described above, the motor 222 is controlled to rotate the valve 220.

  In the stepped automatic transmission 44 of this embodiment, the crank journal 58d corresponds to the input shaft, the rotary shaft 128 corresponds to the intermediate shaft, the clutch housing 66 corresponds to the clutch housing, and the gear 70 is the first gear. The centrifugal clutch portion 82 corresponds to the first clutch portion, the hydraulic clutch portion 96 corresponds to the second clutch portion, the gear 118 corresponds to the second gear, and the gear 134 corresponds to the third gear. The gear 138 corresponds to the fourth gear, and the rotary shafts 140, 234, 248 and 258, the gears 148, 188, 190, 192, 240, 242, 244, 254, 256, 264 and 270, the third speed clutch C3 And the 4-speed clutch C4 is included in the sub-transmission mechanism, the one-way clutch 80 corresponds to the first transmission unit, and the one-way clutch 136 is the second transmission unit. Corresponding to the part.

Next, the function and effect of the stepped automatic transmission 44 will be described.
In the stepped automatic transmission 44, the one-way clutch 80 does not transmit rotation in the first direction from the crank journal 58d (crankshaft 58) to the clutch housing 66. Therefore, when the first speed clutch C1 is not connected, the rotation of the crank journal 58d is not transmitted to the clutch housing 66 even if the crank journal 58d rotates in the first direction. Therefore, the rotation of the crank journal 58d is not transmitted to the output shaft 36, and the rear wheel 34 is not driven.

  As the rotational speed of the crank journal 58d increases, the first speed clutch C1 is connected, and the crank journal 58d and the clutch housing 66 rotate integrally in the first direction. The rotation transmitted from the crank journal 58 d to the clutch housing 66 is transmitted to the gear 134 via the gear 70. Thereby, the gear 134 rotates in the second direction. The rotation of the gear 134 in the second direction is transmitted to the rotation shaft 128 by the one-way clutch 136. Thereby, the rotating shaft 128 and the gear 138 rotate in the second direction. The rotation of the gear 138 is transmitted to the output shaft 36 through a plurality of gears. Thereby, the rear wheel 34 is driven.

  When the gear position of the stepped automatic transmission 44 is set to the second speed or higher, the second speed clutch C2 is connected, and the clutch housing 66 and the hydraulic clutch portion 96 rotate integrally in the first direction. To do. The rotation transmitted from the crank journal 58d to the hydraulic clutch portion 96 via the clutch housing 66 is transmitted to the gear 138 via the gear 118. Thereby, the gear 138 and the rotating shaft 128 rotate integrally in the second direction. Since the one-way clutch 136 does not transmit the rotation of the rotating shaft 128 in the second direction to the gear 134, the gear 134 idles with respect to the rotating shaft 128. The rotation of the gear 138 is transmitted to the output shaft 36 through a plurality of gears according to the state of the third speed clutch C3 and the fourth speed clutch C4. Thereby, the rear wheel 34 is driven.

  Here, in the stepped automatic transmission 44, the one-way clutch 80 transmits the rotation in the first direction from the clutch housing 66 to the crank journal 58d. Therefore, even if the first-speed clutch C1 is disengaged due to a decrease in the rotational speed of the crank journal 58d from the state in which the first-speed clutch C1 and the second-speed clutch C2 are both connected, the first direction of the clutch housing 66 Can be transmitted to the crank journal 58d by the one-way clutch 80. Therefore, when the gear position of the stepped automatic transmission 44 is 2nd speed or more (when the 2nd speed clutch C2 is connected), the gear from the output shaft 36 is disengaged even if the 1st speed clutch C1 is disconnected. The rotation transmitted to 138 can be transmitted to the crank journal 58d via the gear 118, the hydraulic clutch portion 96, the clutch housing 66, and the one-way clutch 80. Thereby, an engine brake can be generated. Thus, in the stepped automatic transmission 44, when the gear position is 2nd or higher, the engine brake can be appropriately generated even when the first-speed clutch C1 is disengaged. Accordingly, it is possible to prevent the deceleration of the scooter 10 from changing when the scooter 10 is decelerated. As a result, it is possible to prevent the rider from feeling uncomfortable.

  Even when the first-speed clutch C1 is disconnected, the rotation of the gear 138 can be transmitted to the crankshaft 58 via the gear 118, the hydraulic clutch portion 96, the clutch housing 66, and the one-way clutch 80. There is no need to further provide the crank journal 58d with a one-way gear for transmitting the rotation of the gear 138 to the crank journal 58d. Thereby, the stepped automatic transmission 44 can be made compact.

  Further, when the rotational speed of the crank journal 58d is higher than the rotational speed of the clutch housing 66, the one-way clutch 80 does not transmit the rotation between the crank journal 58d and the clutch housing 66. Therefore, the rotational speed of the crank journal 58d is higher than the rotational speed of the clutch housing 66 when the gear position of the stepped automatic transmission 44 is set to 2nd speed or more and the first speed clutch C1 is disengaged. In this case, rotation transmission between the crank journal 58d and the clutch housing 66 is interrupted. In this case, since the rotation transmission from the output shaft 36 to the crank journal 58d is interrupted, the generation of the engine brake can be quickly stopped.

  The one-way clutch 80 is provided closer to the centrifugal clutch portion 82 than the plate portion 66 a so as to be accommodated in the clutch housing 66. In this case, a space for providing the one-way clutch 80 need not be secured outside the clutch housing 66. Thereby, the stepped automatic transmission 44 can be made smaller.

  In the above-described embodiment, the stepped automatic transmission 44 having a 4-speed gear position has been described. However, the present invention also applies to a stepped automatic transmission having a gear position of 2nd, 3rd, 5th or more. Applicable.

  In the above-described embodiment, the second-speed clutch C2 is connected by applying hydraulic pressure. However, the second-speed clutch may be configured such that the second-speed clutch is disconnected by applying hydraulic pressure. .

  In the above-described embodiment, the one-way clutch 80 is provided so as to connect the crankshaft 58 and the gear 70. However, even if the one-way clutch is provided so as to connect the crankshaft 58 and the clutch housing 66, the one-way clutch 80 is provided. Good.

  The method of transmitting the rotation from the rotating shaft 128 to the output shaft 36 is not limited to the above example, and a chain for transmitting the rotation may be provided between the rotating shaft 128 and the output shaft 36. Specifically, for example, instead of the rotation shafts 248, 258 and the gears 254, 264, 270, a chain connecting the rotation shaft 234 and the output shaft 36 is provided, and the output shaft is connected to the output shaft 234 via the chain. The rotation may be transmitted to 36.

  The motorcycle to which the present invention is applied is not limited to the scooter 10, and the present invention can also be applied to other motorcycles such as a motorcycle type or a moped.

DESCRIPTION OF SYMBOLS 10 Scooter 30 Engine unit 36 Output shaft 42 Engine 44 Stepped automatic transmission 46 Casing 58 Crankshaft 58d Crank journal 64 First clutch unit 66 Clutch housing 66a Plate part 66b Cylindrical part 80 One-way clutch 82 Centrifugal clutch part 96 Hydraulic type Clutch part 136 One-way clutch 150 Second clutch unit C1 First speed clutch C2 Second speed clutch C3 Third speed clutch C4 Fourth speed clutch

Claims (5)

A stepped automatic transmission having a gear position of at least 2nd speed,
An input shaft rotating in a first direction;
An output shaft that rotates based on rotation transmitted from the input shaft;
A clutch housing provided coaxially with the input shaft and rotatable relative to the input shaft;
A first-speed centrifugal first clutch portion provided on the input shaft so as to rotate integrally with the input shaft inside the clutch housing and to be connected to the clutch housing based on centrifugal force;
For the second speed connected to the clutch housing when the gear position of the stepped automatic transmission is set to at least the second speed and is provided so as to be rotatable relative to the input shaft on the same axis as the input shaft. A hydraulic second clutch portion;
When the first clutch part is connected to the clutch housing and the second clutch part is not connected to the clutch housing, rotation is transmitted between the clutch housing and the output shaft, and the second clutch part A transmission mechanism that transmits rotation between the second clutch portion and the output shaft when the clutch is connected to the clutch housing;
A stepped automatic transmission comprising: a first transmission portion that transmits rotation in the first direction from the clutch housing to the input shaft and does not transmit rotation in the first direction from the input shaft to the clutch housing. .   The first transmission portion rotates between the input shaft and the clutch housing when the rotational speed of the input shaft in the first direction is higher than the rotational speed of the clutch housing in the first direction. The stepped automatic transmission according to claim 1, which does not transmit. The transmission mechanism is
An intermediate shaft provided between the input shaft and the output shaft;
A first gear provided coaxially with the input shaft and rotating integrally with the clutch housing;
A second gear provided coaxially with the input shaft and rotating integrally with the second clutch portion;
A third gear provided coaxially with the intermediate shaft and meshing with the first gear;
A fourth gear provided on the intermediate shaft and meshing with the second gear so as to rotate integrally with the intermediate shaft;
A sub-transmission mechanism for transmitting the rotation of the fourth gear to the output shaft;
A second transmission portion that transmits rotation in the second direction opposite to the first direction from the third gear to the intermediate shaft, and that does not transmit rotation in the second direction from the intermediate shaft to the third gear; The stepped automatic transmission according to claim 1 or 2, comprising: The clutch housing is substantially parallel to the input shaft from the plate portion so as to accommodate at least the first clutch portion inside the hollow substantially disc-shaped plate portion extending in the radial direction of the input shaft. Including an extending cylindrical portion,
The first gear is fixed to the plate portion;
4. The presence according to claim 3, wherein the first transmission unit connects the first gear and the input shaft or the plate unit and the input shaft at least on the first clutch unit side of the plate unit. Stepped automatic transmission.   A motorcycle comprising the stepped automatic transmission according to any one of claims 1 to 4.

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