Abstract: A power unit of a vehicle, which includes an internal combustion engine and a transmission, is provided which is configured to quickly return lubricating oil fed to the transmission to an oil storage portion of the power unit case. The transmission includes a gear train housed in a gear chamber, the gear train executing power transmission among an input shaft, an intermediate shaft and an output shaft. The input shaft and the output shaft are arranged such that a line connecting their respective shaft centers extends almost horizontally above a communicating port which permits return oil flow between segregated portions of the power unit case. In addition, the intermediate shaft is disposed above and between the input shaft and the output shaft.

Abstract: A power unit of a vehicle, which includes an internal combustion engine and a transmission, is provided which is configured to quickly return lubricating oil fed to the transmission to an oil storage portion of the power unit case. The transmission includes a gear train housed in a gear chamber, the gear train executing power transmission among an input shaft, an intermediate shaft and an output shaft. The input shaft and the output shaft are arranged such that a line connecting their respective shaft centers extends almost horizontally above a communicating port which permits return oil flow between segregated portions of the power unit case. In addition, the intermediate shaft is disposed above and between the input shaft and the output shaft.

Abstract: An electric-power-assist transmission and a shaft control method which allow good operability to be obtained. A main clutch is put in an engaged or disengaged state in a manner which is mechanically coupled with the rotation of a shift spindle. At normal times, the rotational direction and the rotational speed of the shift spindle rotated by a driving motor are controlled in accordance with a first control procedure. However, with the main clutch in a disengaged state, as the rotational speed of the engine exhibits a predicted change, the rotational direction and the rotational speed of the shift spindle are controlled in accordance with a second control procedure which is different from the first control procedure.

Abstract: An electric-power-assist transmission and a shift control method which allow good operability to be obtained. In the shift control method, a sleeve is engaged with a target gear. A shift spindle is rotated by a driving motor in order to move the sleeve along a main shaft by using a shift fork and a shift drum interlocked with the shift spindle. When the sleeve is moved to a position in contact with the target gear, PWM control is executed at a duty ratio of 70% during the first 20 ms. Thereafter, the PWM control is executed by changing the duty ratio to 50% and restoring the duty ratio back to 70% repeatedly at intervals of 10 ms.

Abstract: To perform simple and precise shift changes without using a change pedal and a change lever. In conjunction with the engagement and disengagement of a transmission clutch, a shift spindle rotates a shift drum to establish predetermined gear levels, and is rotatably driven via moderator gears by a motor. By operating a shift up switch or shift down switch not illustrated, the motor rotates the shift spindle in a prescribed direction, the transmission clutch and shift drum.

Abstract: An engine mount for a saddle-seat vehicle includes an upper engine mount operatively connected to the engine of the vehicle. The upper engine mount operatively connects the engine to the frame of the vehicle. At least one connector is provided for connecting the engine to the upper engine mount. The upper engine mount permits substantially free vertical movement of the engine relative to the frame. The upper engine mount includes an outer sleeve operatively connected to the frame. The upper engine mount further includes an elastic cushion arranged between the connector and the outer sleeve. The upper engine mount may further include an inner sleeve located within the elastic cushion for passage of the connector therethrough. The upper engine mount further includes a plate bracket operatively connected between the outer sleeve and the frame. The plate bracket may include lightening holes therein for decreasing the weight of the plate bracket while increasing flexibility of the plate bracket.

Abstract: High-temperature oil returning from a cylinder head is to be prevented from being sucked directly into an oil pump through an oil strainer. An oil intake space is defined by partition walls formed near a split plane of both a front casing and a rear casing. The interior of the oil intake space is partitioned into a lower oil chamber and an upper oil chamber by an oil strainer. The lower oil chamber is in communication with the interior of an oil pan through intake ports, while the upper oil chamber communicates with an oil pump. The oil strainer is separately formed as an intake duct and a screen. The oil strainer is fitted and held in a slot formed in the partition wall.

Abstract: A vehicle power transmission apparatus is provided for maintaining a constant power output when driving a vehicle regardless of the change in the frictional force of the belt in a belt type stepless speed change device. A belt type stepless speed change device is used with a vehicle driving, prime motor on board a vehicle. The apparatus provides a flat characteristic segment covering at least a part of the power output characteristic relative to the revolutions of the vehicle driving prime motor. The apparatus allows the vehicle to be driven by a constant power output within the segment of the flat power output characteristic regardless of changes in the frictional force of the belt in the belt type stepless speed change device.