Abstract: 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.

Abstract: According to a method of manufacturing a hollow rack shaft, an approximately rectangular plate having a wide rack tooth portion is bent lengthwise. At this time, the plate has, at the central portion, a flat bottom portion on which rack teeth are formed later and a pair of mutually facing leg portions, and, in the vicinity of both ends, a semicircular bottom portion and a pair of mutually facing leg portions. The mutually facing leg portions at the central portion are bent into a gutter-like cross section having a larger clearance than the clearance of the mutually facing leg portions in the vicinity of both ends. The rack teeth are thus formed on the flat bottom portion through the plastic flow of the flat bottom portion and apart of material of the pair of leg portions of this flat bottom portion. The plate on which the rack teeth have been formed is formed into a tube having a hollow inner surface, by bending the plate and butt-joining the edge portions.

Abstract: 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.

Abstract: 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 through 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.

Abstract: A cam disk for use in a loading cam mechanism of a toroidal type continuously variable transmission comprises a first projecting portion, a second projecting portion, a flange portion, a cam surface, a bearing raceway and a corner section. The cam disk has metal flows along the cam surface, metal flows along a surface of the raceway, and metal flows along a surface of the corner section. To produce the cam disk, material is shaped into a predetermined form through a first forging step using a first die unit, a second forging step using a second die unit, a third forging step using a third die unit, a finishing step, etc. The metal flows are also formed in these steps.

Abstract: 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 .theta. 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.

Abstract: A production process of a yoke a for universal joint using a flat metal sheet to make a yoke for universal joint comprising a base for engaging with an end of a rotary shaft and fixing the end, a pair of arms having respective surfaces opposite to each other and extending in the axial direction of the base from opposite positions in the diameter direction and on one axial edge of the base, and press-worked circular holes coaxial with each other, formed in associated tip portions of said respective arms, wherein in portions of said flat metal sheet to become said respective circular holes, prepared holes having an inner diameter sufficiently smaller than an inner diameter of the circular holes are punched by press working, thereafter the flat metal sheet is curved to form said base and the pair of arms, then rough machining is carried out to punch the portions of the prepared holes in a nearly circular shape by press working, and thereafter press working is carried out to shave an inner peripheral edge of each

Abstract: A yoke of a universal joint for a steering apparatus, the yoke including a coupling member made by press-shaping a metallic plate and formed into the shape of a tube having a split in a circumferential portion thereof and a serration on an inner peripheral surface thereof. The coupling member has one end portion, having a partially cylindrical portion and a pair of flange portions integral with the partially cylindrical portion with the split interposed therebetween, and a substantially cylindrical coupling portion at another end portion thereof. Notably, the substantially cylindrical coupling portion has a larger outer diameter than an outer diameter of the partially cylindrical portion. The coupling member further includes a threaded hole formed in one of the flange portions, and a through hole formed in the other of the flange portions and coaxial with the threaded hole for passing a bolt to be threadably engaged with the threaded hole.

Abstract: In manufacturing a yoke for an elastic universal joint, the time required for each step is shortened and the automation of each step is made easy, and by the energy saving and high efficiency of the manufacturing work, a reduction in the cost is achieved. A metallic plate is subjected to working which can be done easily and within a short time by press work such as stamping work, deep drawing work and ironing work, to thereby make a yoke for an elastic universal joint. This can be accomplished because welding work and cutting work which require much working time and which are cumbersome to automate can be eliminated. Investment in facilities may be small.

Abstract: A hollow steering shaft having a good quality can be manufactured at a low cost by passing a blank tube having a circular cross section through a preliminary shaping die and then through a finishing shaping die. The blank tube which has passed through the preliminary shaping die is formed with two kinds of convex curve surface portions having different radii of curvature and arranged continuously, circumferentially and alternately. When the blank tube passes through the finishing shaping die, the larger convex curve surface portions are deformed into flat portions. As a result, a steering shaft having an elliptical cross section is manufactured.

Abstract: In manufacturing a metal bellows of high rigidity by using relatively simple equipment, a plurality of annular concavities are formed around the outer periphery of an unprocessed tube to form an intermediate product. Then, a core iron is inserted into the intermediate product while the annular concavities around the outer periphery are braced. Subsequently, the intermediate product is pressed in its axial direction to be formed into the metal bellows.

Abstract: A yoke for universal joint is composed of a cylindrical coupling tube formed by pressing a metal plate and having a slit in a radial direction and serrate grooves on the internal periphery; a pair of flanges integrally formed at an end of the coupling tube and positioned on both sides of the slit; and a coupling arm formed by pressing a metal plate. One of the flanges has a screw hole, while the other flange has a hole, coaxial with the screw hole, for passing a bolt to be screwed into the screw hole. The coupling arm has a penetrating hole in the base portion, and mutually coaxial circular holes at its opposite ends. The yoke is assembled by fitting the other end of the coupling tube into the penetrating hole in the base portion, and connecting the other end of the coupling tube with the base portion of the coupling arm.