Ntn Corporation

Hiroshi Bunko

Takahide Saito

Tetsuya Yamamoto

Koichi Okada

Eiji Maeno

Katsuhisa Yamaguchi

A lash adjuster is provided which includes a cylindrical housing having an open top and formed with an internal thread on an inner periphery thereof, a screw rod having an external thread formed on an outer periphery thereof and in threaded engagement with the internal thread, and a spring biasing the screw rod outwardly of the housing. Each of the internal thread and the external thread having a pressure flank configured to receive pressure when a force that tends to push the screw rod into the housing acts on the screw rod, and a clearance flank having a smaller flank angle than the pressure flank. The screw rod has an end protruding from the housing and configured to support an arm of a valve operating mechanism so as to be pivotable about this end. Oil film expelling grooves are formed in the pressure flank of the external thread, using a tap having a thread that extends so as to cross the internal thread.

Lash adjuster

A rotation transmission device includes a roller clutch unit for selectively engaging an inner member mounted on a rotary shaft with an outer ring through rollers, and an electromagnetic clutch unit for electromagnetically controlling the selective engagement by the rollers. The current until the clutch engages is set so as to correspond to a state in which a maximum current according to the revolving speed is required and is varied according to the revolving speed of the rotary shaft to reduce power consumption and the size of the electromagnetic coil.

Rotation transmission device

A rotation transmission device includes an input member, an outer ring mounted around the input member, a two-way clutch and an electromagnetic clutch for selectively engaging and disengaging the two-way clutch, both clutches being mounted between the input member and the outer ring. The electromagnetic clutch includes an armature coupled to a retainer of the two-way clutch so as to be non-rotatable and axially movable relative to the retainer. By energizing its electromagnet, the armature is pulled toward the electromagnet until it is pressed against a rotor fixed to the outer ring. The input member is formed with an oil supply passage. Oil is supplied through the oil supply passage and an oil passage defined between the outer periphery of the input member and the inner periphery of the rotor into a space between the two clutches. The oil passage has a restricted, narrow portion to limit the amount of oil supplied into the above space. This prevents a rise in oil pressure in this space and thus prevents the armature from being pressed against the rotor and the two-clutch from engaging in an untimely manner.

Growing community of inventors

Iwata, Japan

Hiroshi Bunko