Abstract: A driving force transmission system comprising: a coupling case and a shaft arranged rotatably relative to each other; a pilot clutch and a main clutch for controlling a torque transmission between the coupling case and the shaft; an electromagnet for controlling the actions of the pilot clutch and the main clutch; and oil retaining the functions of the pilot clutch and the main clutch. This system further comprises a coupling case, a shaft, a rotor, and X-ring and an O-ring isolating a coupling oil chamber, in which the pilot clutch and the main clutch are arranged, liquid-tight from the surrounding space.

Abstract: A driving force transmission system comprising: a coupling case and a shaft arranged rotatably relative to each other; a pilot clutch and a main clutch for controlling a torque transmission between the coupling case and the shaft; an electromagnet for controlling the actions of the pilot clutch and the main clutch; and oil for retaining the functions of the pilot clutch and the main clutch. This system further comprises a coupling case, a shaft, a rotor, an X-ring and an O-ring for isolating a coupling oil chamber, in which the pilot clutch and the main clutch are arranged, liquid-tight from the surrounding space.

Abstract: A driving force transmission system comprising: a coupling case and a shaft arranged rotatably relative to each other; a pilot clutch and a main clutch for controlling a torque transmission between the coupling case and the shaft; an electromagnet for controlling the actions of the pilot clutch and the main clutch; and oil for retaining the functions of the pilot clutch and the main clutch. This system further comprises a coupling case, a shaft, a rotor, an X-ring and an O-ring for isolating a coupling oil chamber, in which the pilot clutch and the main clutch are arranged, liquid-tight from the surrounding space.

Abstract: A driving force transmission system comprising: a coupling case and a shaft arranged rotatably relative to each other; a pilot clutch and a main clutch for controlling a torque transmission between the coupling case and the shaft; an electromagnet for controlling the actions of the pilot clutch and the main clutch; and oil for retaining the functions of the pilot clutch and the main clutch. This system further comprises a coupling case, a shaft, a rotor, an X-ring and an O-ring for isolating a coupling oil chamber, in which the pilot clutch and the main clutch are arranged, liquid-tight from the surrounding space.

Abstract: A support structure of a power transfer device arranged in parallel with an internal combustion engine and integrally assembled with a transmission unit secured at one side thereof to a cylinder block of the engine, which includes a first stiffener fastened at one end thereof to an end portion of a casing of the power transfer device and at another end thereof to the cylinder block of the engine, a second stiffener fastened at one end thereof to an intermediate portion of the power transfer casing and at another end thereof to the cylinder block of the engine, and a third stiffener fastened at one end thereof to a casing of the transmission unit and at another end thereof to the cylinder block of the engine, wherein the stiffeners are made of cast iron.

Abstract: A differential gear in an automobile, comprising a differential case formed by an annular unit wall structure having a cylindrical outer surface along at least a part of its length, four through holes opening at the cylindrical outer surface at generally constant circumferential intervals, and a circumferential groove on the cylindrical outer surface. Four differential pinions are radially arranged in the case between a pair of opposed side gears for simultaneously mating therewith. The four differential pinions are rotatably supported by one long and two short pinion shafts, the outer ends of which are received by the through holes of the case, respectively. An inner holder maintains a cross configuration of the pinion shafts. An outer ring is fitted on the case for engaging with the outer ends of the pinion shafts and snap ring is provided for retaining the outer ring in place.

Abstract: The present invention relates to a transaxle mechanism for use in a four-wheel drive system of an automotive vehicle. The four-wheel vehicle drive system includes a central differential gear assembly, a front-wheel differential gear assembly, a ring gear and a bevel gear. The central differential gear assembly includes: a toothed wheel which engages with a transmission output gear of a power transmission gear unit; a central differential case fixed to the toothed wheel; a central pinion cross shaft fixed to the central differential case; central differential bevel pinions mounted rotatably on the central pinion cross shaft and central side bevel gears engaging with the central differential bevel pinion.