Nsk Corporation

Nippon Seiko Kabushiki Kaisha

Kiyoshi Okubo

Yasushi Watanabe

Akira Tsubouchi

Hiroshi Iwasa

Satoshi Kadokawa

Shoichi Abe

Takashi Imanishi

Nobuo Gotou

Hiroshi Kato

Hiroyuki Itoh

Nobuo Goto

Makoto Fujinami

Koichi Yokoi

Hideo Ouchi

Nobuaki Mitamura

Kiyoshi Sadakata

Takeo Ohkuma

Takehiko Yumoto

Ritsuo Kuribara

Shouichi Abe

The disk has a traction surface having a concave-arc-shaped cross section which is interposed between a small diameter end portion and a large diameter end portion. In the central portion of the end face of the disk on the small diameter end portion side, there is formed a through hole which extends through the disk up to the large diameter end portion side end face of the disk, while the inner peripheral surface of the through hole is used as an inside diameter surface of the disk. Here, when, among metal flows existing in the disk, a metal flow, which has such a positional relationship with respect to the surface of the disk that an angle &#x3b8; formed between a metal flow on the traction surface side and the tangent of the traction surface is smaller than or equal to 30 degrees, is defined as a 'metal flow along the disk surface', the disk is structured such that the 'metal flow along the disk surface' exists at least in the traction surface.

Disk for toroidal type continuously variable transmission

A wheel-driving unit and a method for manufacturing the same. The circumferential-direction widths of teeth respectively constituting a male spline portion () and a female spline portion () are varied gradually in the respective axial directions of the male and female spline portions (), (). The directions where the widths of the teeth respectively constituting the male and female spline portions (), () increase in the axial direction are set so as to differ from each other, whereby the spline teeth are engaged with each other in a wedge-like manner. A retaining ring () is bridgingly interposed between the outer peripheral surface of the outer end portion of the spline shaft () and the inner peripheral surface of the near-to-outer-end portion of the spline hole () to thereby prevent the spline shaft () from slipping out of the spline hole ().

Wheel drive unit

A hollow rack shaft is manufactured through a first step, a second step and a third step. At the first step, the plate-like workpiece of substantial rectangular shape is press formed into a gutter-like shape. The first die set used at this step is provided with slant die surfaces for canceling elastic recovering generated at the workpiece when the workpiece is removed from the first die set. At the second step, a row of rack teeth is press-formed on the flat bottom portion of the workpiece formed in the first step. The die set used at the second step is provided with a recess for releasing surplus workpiece material within the die clearance at a stroke end of the pressworking. At the third step, each of a pair of legs of the workpiece is bent in a semi-circular shape so as to be butted to each other. At this time, a mandrel is inserted between the legs of the workpiece.

Method for manufacturing a hollow rack shaft

A sheet metal rocker arm manufactured by the steps of punching one metal plate to form a blank having a predetermined contour and through holes, and subjecting this blank to a bending work based on a press work to form a pair of side walls parallel to each other and a connecting portion for connecting the both ends of the side walls in the width direction thereof. This rocker arm is also provided with at least a pair of though holes formed at positions which are aligned with each other on the both side walls and at least one engagement portion provided in a part of the connecting portion. The thickness of at least one engagement portion, is formed to be greater than the thickness of the both side walls.

Sheet metal rocker arm, manufacturing method thereof, cam follower with said rocker arm, and assembling method thereof

A hollow rack shaft is manufactured through a first step, a second step and a third step. At the first step, the plate-like workpiece of substantial rectangular shape is press-formed into a gutter-like shape. At the second step, a row of rack teeth is press-formed by a preliminary forming step and a main forming step on the flat bottom portion of the workpiece formed in the first step. The die set used at the second step is provided with a recess for releasing surplus workpiece material within the die clearance at a stroke end of the pressworking and each die set is divided into a plurality of segments at the recess. At the third step, each of a pair of legs of the workpiece is bent in a semi-circular shape so as to be butted to each other.

Methods are provided for forming a hollow rack shaft from a workpiece comprising a rectangular plate. The workpiece is first bent into a gutter-like shape using a first die set. Rack teeth are then press-formed in a portion of the gutter-like shape using a second die set. The legs, or sides, of the workpiece are then bent around a mandrel into a semi-circular shape so as to butt against each other. Preferably, the die sets and mandrel may be adapted to improve the resulting hollow rack shaft.

The object of the invention is to provide a rack shaft having two rack teeth groups and hollowed throughout the whole body, to lightweightize the shaft and to reduce the cost. The two rack teeth groups are located longitudinally apart from each other and have phase difference related to an angle around the axis of the shaft. After the two rack teeth groups are formed simultaneously or sequentially by die forming on the flat bottoms of the workpiece beforehand gutter-shaped, the legs of the gutter-shaped workpiece are bent to butt to each other and, thereby, a tubular body of the shaft is given to the workpiece. The centers of the material are offset beforehand corresponding to the phase difference.

Hollow rack shaft and manufacturing method thereof

A workpiece for a hollow rack shaft is a substantially rectangular plate. The opposite two sides of this workpiece are respectively provided with a complementary profile composed of the continuation of a convex portion and a concave portion and when the workpiece is cylindrically formed, the profiles are mutually engaged. As the width of a part the width of which is the largest in the convex portion is larger than that of a part the width of which is the smallest in the concave portion, the two sides are prevented from being detached after engagement. Further, the opposite convex portion and concave portion are mutually caulked and hereby, mutual gap is removed.

Method of manufacturing hollow rack shaft

A hollow rack shaft is produced by forming a plate work piece and has continuous metal flow along the contour of rack teeth surface without being cut. A series of wave-like concave-convex sections is formed on the inner surface of the shaft. Thickness of tooth body and tooth bottom of the rack teeth is adjusted by dimensions of the unevenness. Thereby, stress concentration at each point of the rack shaft is prevented and the shaft is strengthened and its weight reduced.

Hollow rack shaft

A loading cam apparatus for a toroidal type continuously variable transmission includes: a first cam surface formed to have concave and convex portions thereon along a circumferential direction thereo, a second cam surface formed to have concave and convex portions thereon along a circumferential direction thereof and to oppose to the first cam surface along an axial direction thereof, a plurality of rolling elements sandwiched between the first cam surface and the second cam surface, and a retainer for holding the plurality of rolling elements in a freely rotatable state. The retainer includes a retainer main body of a circular annular shape, and pockets provided at outer periphery portions of the retainer main body for holding the plurality of rolling elements, respectively. The retainer main body is formed by carbonitriding material of iron system with a carbon concentration in a range from 0.02 to 0.20 wt % both inclusive.

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Maebahshi, Japan

Kiyoshi Okubo