A differential device includes: a differential gear mechanism; and an integrated differential case housing the mechanism, the differential case including bearing bosses formed integrally on one and other side portions thereof and aligned on a same axis to be rotatably supported by a transmission case; a work window being provided in the differential case; sleeves rotatably supported by the bosses and connected to side gears of the mechanism liquid-tightly. The sleeves can be passed through an inside of the differential case from the window and fitted and inserted to inner peripheries of the bosses, falling-off prevention devices are provided between the sleeves and the bosses, and seal devices for preventing lubricating oil in the differential case from flowing out are provided between the side gears and the sleeves. Accordingly, when drive shafts are removed from the differential device, the oil in the transmission and differential cases does not flow out.

A vehicle includes: a power unit including a transmission that changes the speed of rotation produced by output power of a drive source for travel and a case accommodating the transmission, the transmission including a pivotally supported change shaft, the change shaft being angularly movable about an axis to change a gear ratio of the transmission; and an operation unit that operates to angularly move the change shaft, the operation unit including an electric motor and a power transmission structure that transmits power of the electric motor to the change shaft in the form of rotational power by which the change shaft is angularly moved. The operation unit is mounted on an exterior of the case.

A driving force transmission mechanism is equipped with a first gear attached to a drive source, a second gear enmeshed with the first gear, and a damper shaft enmeshed mutually with the second gear and with a rack member of an air mixing damper. A first locator part formed on the second gear is inserted in a first locator groove in the first gear, while additionally, a second locator part is inserted with respect to a second locator groove in a damper gear. Further, a first narrow tooth formed on the first gear enmeshes with a meshing groove of the first locator part, whereas a second narrow tooth formed on the damper gear enmeshes with another meshing groove of the second locator part.

A roller screw mechanism comprising a screw having an outer threading; a nut arranged around and coaxially to the screw, the nut having an inner threading; and a plurality of mutually identical rollers interposed between the screw and the nut. Each mutually identical roller having an outer threading engaged with the outer and inner threadings of the screw and of the nut. The threading of each mutually identical roller being prolonged axially at each end by teeth respectively engaged with teeth of two annular crown rings fixed in an unthreaded part of the bore of the nut. Each of the mutually identical rollers comprises an angular visual positioning feature. The nut comprises an angular visual positioning feature making it possible to angularly place the rollers in the crown ring.

A differential device includes: a differential gear mechanism; and an integrated differential case housing the mechanism, the differential case including bearing bosses formed integrally on one and other side portions thereof and aligned on a same axis to be rotatably supported by a transmission case; a work window being provided in the differential case; sleeves rotatably supported by the bosses and connected to side gears of the mechanism liquid-tightly. The sleeves can be passed through an inside of the differential case from the window and fitted and inserted to inner peripheries of the bosses, falling-off prevention devices are provided between the sleeves and the bosses, and seal devices for preventing lubricating oil in the differential case from flowing out are provided between the side gears and the sleeves. Accordingly, when drive shafts are removed from the differential device, the oil in the transmission and differential cases does not flow out.

A mounting assembly for a coupler mechanism of a motor vehicle has at least a plurality of components which are to be mounted during mounting of the coupler mechanism as the latter is being assembled. A shifting element corresponds to one of the components which is configured to shift a clutch of the coupler mechanism. A first spring element corresponds to one of the components which is received displaceably on the shifting element and which is configured for at least indirect spring force-preloaded support on a housing of the coupler mechanism. The mounting assembly also has a mounting device which is separated from the components in the finally produced state of the coupler mechanism and has a securing element with a first securing element end and a second securing element end. The first securing element end is reversibly coupled releasably to the shifting element and, as a result, secures the first spring element against sliding off the shifting element during mounting.

A work of incorporating a speed reduction mechanism including a scissors gear into a gear case is facilitated. In a state where the angular positions of gear teeth of a first gear and the angular positions of gear teeth of a scissors gear are made to coincide with each other against the elastic force of a torsion spring (19), these angular positions are fixed by a fixing member (position fixing step). The first gear, the scissors gear, and a second gear are housed in a gear case, and the gear teeth of the second gear are made to engage with the gear teeth of the first gear and the gear teeth of the scissors gear (gear incorporating step). The fixing of the angular position of the first gear and the angular position of the scissors gear by the fixing member is released through an opening formed in the gear case.

A multi-sprocket arrangement for installation on a rear wheel axle of a bicycle includes a sprocket assembly. The sprocket assembly has at least a first sprocket and a second, self-supporting sprocket. The second sprocket is connected to a holding body via the first sprocket by way of a separate, cylindrical fastener which extends parallel to the rear wheel axle. The fastener has a first and a second end which are connected in frictionally fit fashion to drilled holes in the first and second sprockets. The frictionally fit connection between the fastener and the drilled holes of the sprockets prevents an axial movement of the first and second sprockets toward one another. The fastener is additionally connected, at the first and second ends, in form-fitting fashion, to the first and second sprockets such that an axial movement of the first and second sprockets away from one another is also reliably prevented.

A differential device includes: a differential gear mechanism; and an integrated differential case housing the mechanism, the differential case including bearing bosses formed integrally on one and other side portions thereof and aligned on a same axis to be rotatably supported by a transmission case; a work window being provided in the differential case; sleeves rotatably supported by the bosses and connected to side gears of the mechanism liquid-tightly. The sleeves can be passed through an inside of the differential case from the window and fitted and inserted to inner peripheries of the bosses, sleeve retainers are provided between the sleeves and the bosses, and seal devices for preventing lubricating oil in the differential case from flowing out are provided between the side gears and the sleeves. Accordingly, when drive shafts are removed from the differential device, the oil in the transmission and differential cases does not flow out.

A centering mechanism is provided with a speed reducer, a bearing that is disposed radially outward from the center line of the speed reducer, and an adapter that is fixed to the speed reducer and maintains the speed reducer and the bearing to be coaxial.