A method of manufacturing a rack bar includes: a rolling die abutment step of bringing a pair of rolling dies into abutment against an intermediate portion of a workpiece; and a ball screw groove forming step of forming a ball screw groove in the workpiece by moving the workpiece relative to the pair of rolling dies so that a region of the workpiece against which the pair of rolling dies is brought into abutment is moved from the intermediate portion toward a first end portion of the workpiece.

A device for cold rolling a thread on a tubular support member of a rotary shouldered thread connection includes obtaining an original root depth of a thread root, cold rolling the thread until a minimum increased root depth tolerance is achieved.

A device for cold rolling a thread on a tubular support member of a rotary shouldered thread connection includes obtaining an original root depth of a thread root, cold rolling the thread until a minimum increased root depth tolerance is achieved.

A rolling tool (5) has a basic body (6) for fastening the rolling tool (5) in a rolling machine (1) and a profiled part (7) for the shaping treatment of a workpiece (2) to be rolled. The basic body (6) and the profiled part (7) are of multi-piece design. The basic body (6) and the profiled part (7), in their interconnected position, are mounted movably relative to one another in a plane perpendicular to the rolling direction (23). The basic body (6) of the rolling tool (5) can also be part of the rolling machine (1).

A cold rolling machine and method for producing a profile on a workpiece. The cold rolling machine having two constructed tool units. Each tool unit has at least one rolling rod extending in the longitudinal direction, a tool slide, a slide drive device, a pivoting carrier and a pivot drive. The at least one rolling rod is fastened to the tool slide and can be moved in the longitudinal direction by the slide drive device. The pivoting carrier can be pivoted about a pivot axis extending in the longitudinal direction by a pivot drive. The tool slide is arranged on the pivoting carrier. An angle of inclination can thereby be set between the two rolling rods, which angle of inclination can have, for example, a value of 0 degrees to 2.0 degrees or to 0.2 degrees. Conical profiles can thereby be produced in the workpiece.

A shaft member includes: an outer peripheral surface; at least one axial side surface facing an axial direction; a chamfered portion formed at a connection portion between an axial end edge of the outer peripheral surface and an outer peripheral edge of the axial side surface; and a processing target portion formed on at least a part of the outer peripheral surface. The chamfered portion includes at least one supported surface portion disposed at an axially intermediate portion of the chamfered portion and inclined radially outward as approaching the processing target portion in the axial direction. The axial end edge of the outer peripheral surface and the outer peripheral edge of the axial side surface are located radially inward than a tangent line at an axially intermediate portion of the supported surface portion, in a cross section in the axial direction.

A shaft member includes: an outer peripheral surface; at least one axial side surface facing an axial direction; a chamfered portion formed at a connection portion between an axial end edge of the outer peripheral surface and an outer peripheral edge of the axial side surface; and a processing target portion formed on at least a part of the outer peripheral surface. The chamfered portion includes at least one supported surface portion disposed at an axially intermediate portion of the chamfered portion and inclined radially outward as approaching the processing target portion in the axial direction. The axial end edge of the outer peripheral surface and the outer peripheral edge of the axial side surface are located radially inward than a tangent line at an axially intermediate portion of the supported surface portion, in a cross section in the axial direction.

Provided is a method for performing an external pipe thread process on a hollow blank by at least twice rolling: firstly, the first rolling wheel group rolls the outer surface of the hollow blank into a threaded cylindrical surface or a threaded conical surface or a threaded cylindrical conical mixing surface, and secondly, the second rolling wheel group rolls again for the outer surface of the hollow blank which has processed in step 1, and rolling to form an external pipe thread; wherein the number of rolling wheels in a rolling wheel group, used in any two back-to-back rolling processes in a processing sequence, are different in parity. Further provided are various rolling head, module, apparatuses and production line for pipe thread, achieving the above processing method and having a simple structure, portability and practicality. When preforming an external pipe thread rolling process of the hollow blank, thereby improving a processing yield; in addition, the invention also provides a threaded cylindrical surface or a threaded conical surface or threaded cylindrical conical mixing surface products by the first rolling wheel group.

Provided is a method for performing an external pipe thread process on a hollow blank by at least twice rolling: firstly, the first rolling wheel group rolls the outer surface of the hollow blank into a threaded cylindrical surface or a threaded conical surface or a threaded cylindrical conical mixing surface, and secondly, the second rolling wheel group rolls again for the outer surface of the hollow blank which has processed in step 1, and rolling to form an external pipe thread; wherein the number of rolling wheels in a rolling wheel group, used in any two back-to-back rolling processes in a processing sequence, are different in parity. Further provided are various rolling head, module, apparatuses and production line for pipe thread, achieving the above processing method and having a simple structure, portability and practicality. When preforming an external pipe thread rolling process of the hollow blank, thereby improving a processing yield; in addition, the invention also provides a threaded cylindrical surface or a threaded conical surface or threaded cylindrical conical mixing surface products by the first rolling wheel group.

With respect to a linear motion shaft in which a rack shaft part and a ball screw shaft part are joined to each other by friction welding, coaxiality of a portion having a rack shaft part and a portion having a ball screw shaft part is improved. In a state where a gripped portion 56 formed on the screw shaft part 29 is gripped by a first gripping tool 57 for centering, and a rack shaft part 28 is gripped by a second gripping tool 58 for centering, end portions in the axial direction of the rack shaft part 28 and the screw shaft part 29 are abutted to each other while the screw shaft part 29 and the rack shaft part 28 are relatively rotated by rotating the first gripping tool 57, so that the rack shaft part 28 and the screw shaft part 29 are joined to each other by friction welding.