Ntn Corporation

Nissan Motor Company Limited

Eiji Maeno

Ken Yamamoto

Kenshi Ushijima

Yoshiteru Yasuda

Satoshi Kitano

Tadahisa Tanaka

Kouichi Onimaru

Yasumasa Hibi

Hiroshi Bunko

Katsuhisa Yamaguchi

Kiyohiro Ito

Kengo Watanabe

A brake-side clutch part includes an outer ring whose rotation is restricted and an output shaft from which rotation is output. The outer ring is provided with a slide gear that meshes with the output shaft when rotational torque is cut off and releases a meshing state with the output shaft when rotational torque is transmitted. The output shaft is provided with an inner gear that meshes with the slide gear so as to be slightly rotatable. An alignment part that aligns a phase of the inner gear with that of the slide gear when rotational torque is cut off, and a centering part that returns the inner gear to a neutral position with respect to the output shaft when rotational torque is transmitted are provided between the inner gear and the output shaft.

Clutch unit

A chain tensioner is formed with internal threads each including a push-in-side flank, a protruding-side flank, and a thread top face. The push-in-side flank has a flank angle which is larger than a flank angle of the protruding-side flank. The push-in-side flank and the protruding-side flank are rolled surfaces formed by rolling, and have a surface roughness smaller than Ra 1.0 &#x3bc;m. Each internal thread further includes, at a position at which the protruding-side flank intersects with the thread top face, a chamfer configured to receive a bulge resulting from excess materials pushed out from the protruding-side flank during formation of the internal thread by rolling.

Chain tensioner

A hydraulic auto-tensioner includes a plunger fitted to a bottom end portion of a rod so as to be slidable along a radially inner surface of a valve sleeve and a radially outer surface of the rod. The plunger has a bottom plate formed with a valve hole. A first leakage gap is defined between sliding surfaces of the plunger and the valve sleeve, and a second leakage gap of which the flow resistance is lower is defined between sliding surfaces of the plunger and the rod such that while the engine is running normally, oil in a pressure chamber leaks into a reservoir chamber through the second leakage gap, and when starting the engine by actuating a starter/generator, the plunger rises until the valve hole is closed so that oil in the pressure chamber leaks into the reservoir chamber through the first leakage gap.

Hydraulic auto-tensioner

A center motor power-assisted bicycle includes an internal transmission and has a regenerative function. A transmission comprises, in a drive wheel hub, a planetary gear, a one-way clutch for reverse input, a clutch switching device, and, a sun gear and transmits driving force from a sprocket to the drive wheel. A transmission control mechanism selectively rotationally fixes the sun gear to the axle to change speed when driving force is applied. The clutch is disposed between the sun gear and the axle, and selectively rotationally fixes the sun gear to the axle by the operation of the clutch switching device when reverse input is applied. While the bicycle is driven, the clutch switching device moves the clutch to the rotatable state, to transmit driving force. While the bicycle is traveling without being driven, the clutch is locked, so that reverse input is transmitted to the sprocket.

Power assisted bicycle with regenerative function

The object is to provide a lash adjuster that can be easily and repeatedly mounted on a swing arm type valve gear, having an adjusting screw that can be repeatedly held in a pushed-in state with a general-purpose turning tool such as a wrench. A serrated internal threadis formed on the inner circumferential face of a cylindrical bodyhaving closed bottom end, and a serrated external threadformed on the outer circumferential face of an adjusting screwengages with the internal thread. A return springis mounted in the body to bias the adjusting screwin the protruding direction. A friction memberis provided between the bottom faces of the adjusting screwand the body. A spherical pivot portionis formed on the top of the adjusting screw, and an engaging holeis formed in the top end of the pivot portion. The adjusting screw is rotated in the fastening direction by rotating operation of a turning tool T engaging with the engaging hole, and the bottom face of the adjusting screwis pressed against the friction member, thereby holding the adjusting screwin pushed-in state and making mounting of the lash adjuster to a swing arm type valve gear easy.

Lash adjuster for swing arm type valve gear

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

This invention provides a chain tensioner that is compact, excellent in operation, easy to maintain and handle and low in manufacturing cost. This chain tensioner has a tubular housinghaving a bottom, a plungerinstalled in the inner peripheryof the housing so as to smoothly slide inside the housing, a return springproviding the plungerwith a force pushing outward, a plurality of latching grooves-formed on the outer periphery of the plunger, a resister ringcapable of locking in the latching grooves, and a check valvethat is mounted on the bottom of the housing inner periphery, provides the housing inner peripherywith operating oil and prevents its reverse flow. The range of backward movement of the plungeris limited by mating the resister ringlocked in the latching grooves-with a first stopperformed on the housing inner periphery

Chain Tensioner

This invention provides a chain tensioner that is compact, excellent in operation, easy to maintain and handle and low in manufacturing cost. This chain tensioner has a tubular housinghaving a bottom, a plungerinstalled in the inner peripheryof the housing so as to smoothly slide inside the housing, a return springproviding the plungerwith a force pushing outward, a plurality of latching groovesformed on the outer periphery of the plunger, a resister ringcapable of locking in the latching grooves, and a check valvethat is mounted on the bottom of the housing inner periphery, provides the housing inner peripherywith operating oil and prevents its reverse flow. The range of backward movement of the plungeris limited by mating the resister ringlocked in the latching grooveswith a first stopperformed on the housing inner periphery

In a lash adjuster of a valve gear which employs a serration-shaped thread mechanism, the formation of a tribochemical reactive film is suppressed by using as the materials for its adjuster screw and nut member (or the materials for their thread surfaces) materials that, even if FM oil is used, the friction coefficient will not extremely decrease. The nut member is provided on the underside of an end plate of a lifter body. The adjuster screw is threadedly engaged in a threaded hole of the nut member. The adjuster screw is biased by a return spring. The female threads of the threaded hole and the male threads of the adjuster screw are serration shaped. One or both of the nut member and the adjuster screw, or the pressured thread surfaces of one or both of them, are formed of a material that will not react with oil additives of FM oil to suppress the formation of tribochemical reactive film, thereby stabilizing the operation of the lash adjuster.

Lash adjuster for valve gear

A lash adjuster in a valve actuator includes a lifter body having an end plate having its top surface in contact with a cam and formed with a threaded hole in its bottom surface. An adjuster screw is inserted in the threaded hole with its external thread in engagement with the internal thread of the threaded hole. An elastic member is mounted in the threaded hole over the adjuster screw to bias the adjuster screw axially downward. Both of the threads have a sawtooth-shaped section with its pressure flank having a greater flank angle than its clearance flank. One of the pressure flanks is formed with a satin-finished rugged surface which is covered by a hard film which is non-reactive with a low-friction oil. With this arrangement, even after the threads have become worn, the friction coefficient between the thread surfaces is kept substantially constant.

Lash adjuster for valve actuator

For an arm type valve gear in which a lash adjuster is mounted between an arm pivoted by the rotation of a cam and a valve stem, it is a goal to reduce the axial length of the lash adjuster and to suppress wear at the contact portion with the valve stem. An engaging hole is formed in an arm pivoted by the rotation of a cam at a position corresponding to the top end face of a valve stem. A lash adjuster received in the engaging hole includes a nut member, an adjuster screw in threaded engagement with the nut member, an elastic body biasing the adjuster screw toward the valve stem, and a ball joint to reduce the axial length of the lash adjuster. Further, by bringing the bottom end face of the ball joint into surface contact with the top end face of the valve stem, wear at the contact portion is suppressed.

Arm type valve gear

A lash adjuster is provided which can keep a constant valve lifting amount. An adjust screw is brought into threaded engagement in a threaded hole formed in the bottom surface of an end plate of a lifter body. The adjust screw is biased in the axial direction by an elastic member. The threads of female threads of the threaded hole and the male threads on the adjust screw are serrated. The surface roughness of the pressure flanks of the serrated threads is set to 0.4 or over to prevent the adjust screw from retracting while turning when push-in loads are applied to the adjust screw from the valve stem, thereby stabilizing the valve lifting amount. Also, a slide member is mounted between the adjust screw and the valve stem and a retaining device is provided to prevent the slide member from turning relative to the nut member while supporting it so as to be movable in the axial direction.

Growing community of inventors

Shizuoka, Japan

Eiji Maeno