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US 2003/0145817 A1Published application
Lash adjuster for use in valve gear
AssigneeNtn Corporation
InventorsKen Yamamoto, Eiji Maeno
Life of this patent
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AssigneeNtn Corporation
InventorsKen Yamamoto, Eiji Maeno
Estimating the term…
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 means 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.
A lash adjuster for use in a valve gear, comprising a lifter body having an end plate, mounted between a cam and a valve stem and supported so as to be slidable in the axial direction, an adjust screw in threaded engagement with a threaded hole formed in the bottom surface of the end plate of said lifter body, and an elastic member biasing said adjust screw toward the top end of said valve stem, wherein threads of female threads of said threaded hole and male threads formed on the outer periphery of said adjust screw are serrated so that the flank angle of pressure flanks of the male threads and the female threads, which receive axial push-in force applied to said adjust screw, is larger than the flank angle of clearance flanks of the male threads and the female threads, wherein the surface roughness Ra of the pressure flanks of at least one of said female threads and said male threads is set to 0.4 or over.
A lash adjuster for use in a valve gear, comprising a lifter body having an end plate and mounted between a cam and a valve stem so as to be slidable in the axial direction, a nut member fixedly mounted on the bottom surface of said end plate of said lifter body, an adjust screw in threaded engagement with a threaded hole formed in said nut member, and an elastic member mounted in said threaded hole to bias said adjust screw in the axial direction, wherein threads of female threads of said threaded hole and male threads formed on the outer periphery of said adjust screw are serrated so that the flank angle of pressure flanks of the male threads and the female threads, which receive axial push-in force applied to said adjust screw, is larger than the flank angle of clearance flanks of the male threads and the female threads, wherein a slide member is mounted between said adjust screw and said valve stem and a retaining means is provided to prevent said slide member from turning relative to said nut member while supporting it so as to be movable in the axial direction.
Dependencies are inferred from the claim text.