Koyo Seiko Company, Ltd.

Jtekt Corporation

Atsushi Yao

Hirokazu Arai

Youzou Taniguchi

Shinji Abe

Hiroshi Komiya

Satoru Murao

Masahiro Mukasa

Tomohiro Haruta

Yoichiro Sankai

Nao Ito

A transmission ratio variable mechanism includes an input member and an output member, which are rotatable around a first axis, an inner ring arranged to connect the input and output members to each other so as to be differentially rotatable, an outer ring, and a motor. A second axis serving as a center axis of the inner ring and the outer ring is inclined to the first axis. The transmission ratio variable mechanism includes uneven engagement sections including a projection provided on one of each of end surfaces of the inner ring and a power transmission surface corresponding to the end surface, and a recess. The inner ring includes a first member forming the first end surface and a second member forming the second end surface. The first and second members are formed separately from each other and coupled to each other so as to be movable together.

Transmission ratio variable mechanism and vehicle steering apparatus

In a grease composition which essentially comprises a base oil and a thickener, a mixture of a urea compound and lithium soap is blended as the thickener. The content of the urea compound in the thickener is preferably set to 20 to 80 wt %. As the urea compound, an alkyl group- or cyclohexyl group-terminated diurea compound, or, particularly, a diurea compound in which the diisocyanate component is 4,4&prime;-diphenylmethane diisocyanate is preferably used. In a rolling bearing which is lubricated by the grease composition, the acoustic performance is largely improved by a synergistic action of the lithium soap and the urea compound, and simultaneously also the anti-fretting property is enhanced by an action of the urea compound.

Grease composition and rolling bearing lubricated by the grease composition

Within bounds on both sides of an axial center of each of the raceways of an outer and inner ring, a curvature radius of a raceway portion in a dimensional range covering at least 45% of a raceway width with respect to the axial center thereof is defined to be within the range of between &plusmn;1 &mgr;m to/from a mean curvature radius of the raceway in the dimensional range.

Rolling bearing

A crown cage is applied to a ball bearing for high-speed rotation for a dental hand piece or the like. The cage has a cylinder formed by injection molding of a thermoplastic resin, and pockets for holding balls that are formed at a predetermined circumferential pitch in the cylinder. A first recess including a gate cutting trace at the time of molding, and second recesses for correcting rotational imbalance of the cylinder caused by the first recess, are formed in the cylinder. The recesses have almost the same shape, and are arranged at a predetermined circumferential pitch.

Crown cage for ball bearing and dental hand piece including the same

There is provided a dental handpiece capable of stably supporting a turbine during high-speed rotation thereof. A projection is provided at each corner portion of a polygonal end surface of a retainer. The projections prevent a conical spring washer from deviating from a centered position relative to the central axis of the turbine. First and second ball bearings for supporting the turbine are axially pressed with a sufficient force which is symmetrical about the central axis of the turbine. A sufficient axial pre-load can be applied to the first and second ball bearings by the conical spring washer, and the conical spring washer is prevented from being displaced.

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Kashihara, Japan

Atsushi Yao