Abstract: An engine unit includes a multi-speed transmission provided with a plurality of clutches, and enables assembly and maintenance of clutches and a sprocket wound with a drive chain to be easily performed. In an engine unit chassis, a drive shaft arranged to output a drive to a rear wheel via a sprocket provided at one end in the lateral direction, and a second main shaft are arranged parallel or substantially parallel to a crankshaft provided in approximately a lateral direction of the vehicle. A second clutch that transfers rotation power from the crankshaft to the second main shaft is detachably connected to one of the second main shaft, which projects from the engine unit chassis beyond one end of the drive shaft, in a position to overlap with at least portion of the sprocket axially sideways with respect to the drive shaft.

Abstract: A combination torsion spring is configured such that a predetermined reaction force is generated in a coil circumferential direction without a center of a wound coil tilting even when applied with a load. A first torsion spring and a second torsion spring of the combination torsion spring are each provided with a coil. Each coil is formed by spirally winding a copper wire in a different winding direction from one another. The inner diameter of the coil of the first torsion spring is approximately the same as the outer diameter of the coil of the second torsion spring. In the combination torsion spring, the coil of the second torsion spring is inserted into the coil of the first torsion spring.

Abstract: A dual clutch automated manual transmission includes a first clutch and a second clutch, and a clutch torque capacity command value for a plurality of clutch actuators arranged to drive the first clutch and second clutch based on operation of a by-wire type of clutch lever, wherein the clutch torque capacity of the plurality of clutches is controlled. An operator can adjust a driving force by manually operating the clutch in the transmission in which a clutch operation is controlled automatically, such as an automatic transmission system, automated manual transmission system, or dual clutch automated manual transmission system, thereby improving drivability.

Abstract: In an engine unit, a drive unit case includes a crank shaft disposed in a left-right direction of a vehicle, a drive shaft and a second main shaft. A transmission shaft is parallel or substantially parallel to the drive shaft and transmits rotational power, which has been transmitted via a middle gear, to a propeller shaft. A second clutch, which transmits rotational power from the crank shaft to the second main shaft, is freely detachably connected to an end of one side of the second main shaft which protrudes from a drive unit case more than the end of one side of the drive shaft, at a position that overlaps with at least one section of the middle gear on the side of the shaft direction of the drive shaft.

Abstract: A dual clutch automated manual transmission includes a first clutch and a second clutch, and a clutch torque capacity command value for a plurality of clutch actuators arranged to drive the first clutch and second clutch based on operation of a by-wire type of clutch lever, wherein the clutch torque capacity of the plurality of clutches is controlled. An operator can adjust a driving force by manually operating the clutch in the transmission in which a clutch operation is controlled automatically, such as an automatic transmission system, automated manual transmission system, or dual clutch automated manual transmission system, thereby improving drivability.

Abstract: An engine unit includes a multi-speed transmission provided with a plurality of clutches, and enables assembly and maintenance of clutches and a sprocket wound with a drive chain to be easily performed. In an engine unit chassis, a drive shaft arranged to output a drive to a rear wheel via a sprocket provided at one end in the lateral direction, and a second main shaft are arranged parallel or substantially parallel to a crankshaft provided in approximately a lateral direction of the vehicle. A second clutch that transfers rotation power from the crankshaft to the second main shaft is detachably connected to one of the second main shaft, which projects from the engine unit chassis beyond one end of the drive shaft, in a position to overlap with at least portion of the sprocket axially sideways with respect to the drive shaft.

Abstract: In a twin clutch transmission, a first main shaft transfers rotation power of a crankshaft that is provided in parallel, input via a first clutch, to a drive shaft via an odd-numbered transmission gear mechanism. A second main shaft transfers rotation power of the crankshaft that is provided in parallel, input via a second clutch, to the drive shaft via an even-numbered transmission gear mechanism. In a first power transfer path running from the crankshaft to the drive shaft via the first clutch and a second power transfer path running from the crankshaft to the drive shaft via the second clutch, back torque limiters are provided that, when reverse torque operates in a direction opposite the direction for acceleration of a rear wheel, limits transfer of the reverse torque.

Abstract: A shift mechanism that provides a shift mechanism for enabling smooth gear shifting by a transmission, and a vehicle equipped therewith. With this mechanism, a shift drum, to which shift forks are connected via grooves on an outer periphery, is held every predetermined rotation angle. When differences are produced in the degree of rotation between a third rotating member that rotates by motor rotation and a second rotating member that rotates in accordance with the third rotating member, bias is accumulated in a torsion spring. Bias that is accumulated is released when the rotation angle of the third rotating member equals or exceeds a predetermined angle of rotation, rotating a first rotating member via a second rotating member, and rotating the shift drum quickly.

Abstract: A twin clutch transmission can be made sufficiently small and can easily be mounted on a motorcycle without biasing the lateral weight balance. In this transmission, a first clutch is arranged to input rotation power transferred from a crankshaft to a first main shaft and to output the rotation power to a rear wheel via an odd-numbered transmission gear mechanism, and a second clutch is arranged to input rotation power transferred from the crankshaft to a second main shaft and to output the rotation power to the rear wheel via an even-numbered transmission gear mechanism.