Abstract: A clutch includes an automatic play adjusting mechanism interposed between a pressure plate and a pull rod, to allow movement of the pressure plate relative to the pull rod in a clutch axial direction in a clutch connected state, and to restrict the movement of the pressure plate relative to the pull rod in the clutch axial direction when the pull rod moves more than a prescribed play amount in the clutch axial direction. As a result, the clutch can restrict the shift of a touch point caused by thermal expansion or wear, and the play amount of the clutch can be adjusted automatically.

Abstract: A stationary sheave half of a V-belt type continuously variable transmission (CVT) comprises a primary sheave mounted to a primary sheave shaft and a secondary sheave mounted to a secondary sheave shaft. The stationary sheave half of the secondary sheave comprises a sheave body, which is substantially in the form of a doughnut plate and around which a V-belt is wound, and a substantially cylindrical-shaped boss portion extending rightward from a right side of the sheave body. The sheave body and the boss portion are formed separately.

Abstract: A clutch 44 has a clutch boss 441, a clutch housing 442, a friction plate 64, a clutch plate 65, and a pressure plate 450. The clutch boss 441 is attached to the main shaft 41 so as to be integrally rotated therewith. The clutch housing 442 encloses the periphery of the clutch boss 441 and is attached to the main shaft 41 so as to be rotated with respect to the main shaft 41. The friction plate 64 has a plate main body and a friction material and rotates together with the clutch housing 442. The clutch plate 65 faces the plate main body via the friction material and rotates together with the clutch boss 441. The pressure plate 450 rotates together with one of the clutch boss 441 the clutch housing 442 which is engaged with the friction plate 64.

Abstract: An engine unit for a motorcycle that efficiently supplies lubricating oil to a clutch mechanism includes a connecting rod connected to a crank shaft, an oil pump, a clutch shaft having a clutch shaft body and a centrifugal type clutch, and a reduction mechanism having a reduction shaft in parallel to the crank shaft. The oil pump supplies lubricating oil to a connection of the crank shaft and the connecting rod. The clutch shaft body is arranged in parallel to the crank shaft. The clutch shaft body is closer to the crank shaft than is the reduction shaft. Lubricating oil supplied to the connection to scatter is led to the clutch shaft.

Abstract: A belt-type continuously variable transmission includes a primary sheave including a pair of first clamp surfaces, a secondary sheave including a pair of second clamp surfaces, and a belt endlessly wound between both of the primary and secondary sheaves. The belt includes contact surfaces clamped between the first clamp surfaces and between the second clamp surfaces. Powder having infusibility as a friction enhancing material is held on at least one of the first clamp surfaces of the primary sheave, the second clamp surfaces of the secondary sheave, and the contact surfaces of the belt.

Abstract: A belt-type continuously variable transmission includes a primary sheave including a pair of first clamp surfaces, a secondary sheave including a pair of second clamp surfaces, and a belt endlessly wound between both of the primary and secondary sheaves. The belt includes contact surfaces clamped between the first clamp surfaces and between the second clamp surfaces. Powder having infusibility as a friction enhancing material is held on at least one of the first clamp surfaces of the primary sheave, the second clamp surfaces of the secondary sheave, and the contact surfaces of the belt.

Abstract: A belt-type continuously variable transmission includes a primary sheave including a pair of first clamp surfaces, a secondary sheave including a pair of second clamp surfaces, and a belt endlessly wound between both of the primary and secondary sheaves. The belt includes contact surfaces clamped between the first clamp surfaces and between the second clamp surfaces. Powder having infusibility as a friction enhancing material is held on at least one of the first clamp surfaces of the primary sheave, the second clamp surfaces of the secondary sheave, and the contact surfaces of the belt.

Abstract: A friction plate (131) rotates in association with rotation of a pressure plate (77). A first pressing plate (132) presses the friction plate (131) to the right to move the pressure plate (77) to the right. A second pressing plate (133) receives a torque of the pressure plate (77) via the friction plate (131). A slide shaft (231) rotates together with the second pressing plate (133). The operation assist mechanism (220) gives a rightward force to the pressure plate (77), by the slide shaft (231) moving to the right upon receiving the torque from the second pressing plate (133). Balls (135) transmit a portion of the rightward force of the short push rod (43a) to the slide shaft (231) without use of the friction plate (131).

Abstract: According to some preferred embodiments, a clutch housing (46) of a clutch (2) has a bottom portion (46a) in a closed-end cylindrical shape, a plurality of arms (46d) extending along an axial direction from the bottom portion (46a) and provided along a circumferential direction centering on an axial center (C) of the clutch shaft (33), and a plurality of gaps (46e) formed between adjacent arms (46d). Off-springs (71) are arranged in the gaps and extend along the axial direction.

Abstract: A cam face 81 and a cam face 181 are formed in such a manner that an angular velocity ? represented by the following equation increases when a parameter R increases and the angular velocity ? decreases when the parameter R decreases, ?2=(1/m)·[F(tan ?+tan ?)/R], where the mass of the centrifugal weight (41) is m, the revolution radius that is the distance from the rotation center (0) of the centrifugal weight (41) to the center of gravity of the centrifugal weight (41) is R, the angle formed by a radial line (L0) and a tangent line (L1) of a point of the cam face (81) being in contact with the centrifugal weight (41) is ?, the angle formed by a radial line (L0) and a tangent line (L2) of a point in the cam face (181) being in contact with the centrifugal weight (41) is ?, and the urging force of a Belleville spring that urges a roller retainer (78) is F.

Abstract: A motorcycle having a belt type CVT and an engine unit in which an axial length of a cylinder is restricted. A body frame comprises a down frame extending vertically. The engine unit comprises a four-stroke engine, a belt type CVT, a clutch and a crank case. A cylinder is arranged rearwardly of the down frame with an axis thereof extending vertically. The clutch is provided between a secondary sheave shaft and an output shaft. The crank case is formed with an oil reservoir portion below a crank shaft to store lubricating oil. A rear end of the oil reservoir portion is rearward of a front end of a secondary sheave. An axis of the crank shaft is below an axis of the secondary sheave shaft.

Abstract: A noise suppressor for a straddle-type vehicle provided with a belt type continuously variable transmission having a resin-block-type belt. A portion of an air passage for guiding air to a belt chamber is formed in a closed casing. The closed casing includes a dish-shaped first casing member and a dish-shaped second casing member. An inlet port and an exhaust port are formed in the second casing member. Partition walls in the form of curved plate pieces are formed in the first casing and second casing members. Air flow paths formed by the partition walls are U-shaped, thereby forming a serpentine flow.

Abstract: A riding type vehicle with improved cooling function of a V-belt continuously variable transmission and a compact body cover. A front side of a seat is partitioned with a space recessed to a lower side. The inside of a vehicle body cover is partitioned with a center tunnel. An engine unit is supported by a vehicle body frame on a lower side of the recessed space. The engine unit includes a transmission case having a belt chamber containing the V-belt continuously variable transmission. A footrest is arranged on an outer side in a vehicle width direction of the transmission case. An intake duct that guides air for cooling the V-belt type continuously variable transmission is disposed on an outer side in a vehicle width direction of the center tunnel and on an upper side of the transmission case.

Abstract: A belt-type continuously variable transmission (15) includes a primary sheave (29) having a pair of first clamp surfaces (37a, 37b), a secondary sheave (30) having a pair of second clamp surfaces (51a, 51b), and a belt (31) endlessly wound between both the sheaves (29, 30). The belt (31) has contact surfaces (58a, 58b) clamped between the first clamp surfaces (37a, 37b) and between the second clamp surfaces (51a, 51b). Powder (64) having infusibility as a friction enhancing material is held on at least one of the first clamp surfaces (37a, 37b) of the primary sheave (29), the second clamp surfaces (51a, 51b) of the secondary sheave (30), and the contact surfaces (58a, 58b) of the belt (31).

Abstract: A belt-type continuously variable transmission that is easily manufactured includes a belt wound around a primary sheave and a secondary sheave. The primary sheave includes a fixed sheave member, a movable sheave member, a cam plate, and a roller weight. The movable sheave member has a guide rib extending toward the cam plate. The cam plate has a slider having a guide groove. The position of the radially outer portion of an end surface of the slider is shifted toward the right in the rotation axis extending direction from the position of the radially inner portion of the end surface.

Abstract: A secondary sheave shaft of a transmission is disposed vertically higher than a drive shaft when viewed along the axial direction of the shafts. An idle shaft of a speed-reduction mechanism is disposed between a primary sheave and an imaginary plane that extends through an axis of rotation of the secondary sheave shaft and an axis of rotation of the drive shaft. The drive shaft is disposed inside a profile of a transmission case when viewed along the axial direction of the secondary sheave shaft and the drive shaft.

Abstract: A friction clutch has a clutch housing including a friction plate, a clutch boss including a clutch plate, and a pressure plate causing the friction plate and the clutch plate to contact each other by moving in a predetermined direction. A clutch spring applies a biasing force in a direction of causing the pressure plate to press the friction and clutch plates into contact with each other. An annular retainer receives a reaction force to the biasing force of the clutch spring by supporting one end of the clutch spring opposite to the pressure plate. A circlip of a notched ring shape is fitted into an inner peripheral side of the clutch housing. The circlip locks the retainer to the clutch housing by abutting on an opposite side of the retainer. The retainer is configured to suppress radially inward deformation of the circlip when a vehicle engine is driven.

Abstract: A friction clutch has a clutch housing including a friction plate, a clutch boss including a clutch plate, and a pressure plate causing the friction plate and the clutch plate to contact each other by moving in a predetermined direction. A clutch spring applies a biasing force in a direction of causing the pressure plate to press the friction and clutch plates into contact with each other. An annular retainer receives a reaction force to the biasing force of the clutch spring by supporting one end of the clutch spring opposite to the pressure plate. A circlip of a notched ring shape is fitted into an inner peripheral side of the clutch housing. The circlip locks the retainer to the clutch housing by abutting on an opposite side of the retainer. The retainer is configured to suppress radially inward deformation of the circlip when a vehicle engine is driven.

Abstract: A centrifugal clutch for an engine includes a pressure plate that presses a friction plate into a clutch plate is provided. The clutch may include a plurality of roller weights that move on respective cam surfaces in a radially outward direction relative to the pressure plate in accordance with the magnitude of a centrifugal force generated by rotation of a drive side rotating body. The pressure plate presses the friction plate into the clutch plate with a force corresponding to the amount of movement. An elastic member is operatively coupled to the pressure plate to cause the friction and clutch plates to stay in pressed contact even when the engine is in a stopped state.

Abstract: A two wheeled vehicle has a frame assembly. The frame assembly comprises a backbone style frame. A power unit is mounted to the frame. A space is defined between the power unit and the frame such than an auxiliary component can be positioned within the space.