A method of making an interaxle differential unit. The method may include piercing a workpiece and then ring roll forging the workpiece to form an annular case that is a seamless ring. The annular case may be heat treated before installing an interaxle differential unit gear nest inside the annular case.

A method for manufacturing a linear motion shaft includes: manufacturing a first shaft portion, and connecting the first shaft portion and a second shaft portion by friction welding. A first input section is formed in a material for the first shaft portion to obtain the first shaft portion and then a gripped section for centering is formed on the outer peripheral surface of an axially end portion of the first shaft portion on the side connected to the second shaft portion based on the first input section. The friction welding is performed by abutting the axially end portions of the first shaft portion and the second shaft portion in a state where the gripped section is gripped by a first gripping tool for centering, the first shaft portion is rotated with the first gripping tool, and the second shaft portion remains without rotating.

A method for manufacturing a linear motion shaft includes: manufacturing a first shaft portion, and connecting the first shaft portion and a second shaft portion by friction welding. A first input section is formed in a material for the first shaft portion to obtain the first shaft portion and then a gripped section for centering is formed on the outer peripheral surface of an axially end portion of the first shaft portion on the side connected to the second shaft portion based on the first input section. The friction welding is performed by abutting the axially end portions of the first shaft portion and the second shaft portion in a state where the gripped section is gripped by a first gripping tool for centering, the first shaft portion is rotated with the first gripping tool, and the second shaft portion remains without rotating.

The present disclosure relates to a steel forging process, in particular a hot steel forging process in horizontal press of a metal tube, preferably a cylindrical steel tube.

A method can be employed to produce a rack for a steering gear. The rack may include a toothed portion with a toothing, and a shaft portion with a functional portion. Separate segments comprising at least one in each case bar-shaped toothed segment and one shaft segment may be provided, which are aligned on a common longitudinal axis and are connected to one another at a joint. The method may involve providing a shaft raw material piece having a length that is a multiple of a shaft segment length, continuously grinding a part of a circumferential face of the shaft raw material piece across a multiple of the shaft segment length to produce a semi-finished shaft segment product, cutting to length a shaft segment from the semi-finished shaft segment product, providing a toothed segment, and joining the shaft segment to the toothed segment.

A rack for a steering gear includes a toothed portion with a toothing extending along a longitudinal axis, and a generally cylinder-segment-shaped back opposite the toothing and having a back radius. A method for producing such a rack includes forming a cylindrical blank with an unmachined radius between a toothed die part having a toothed mold clearance and a back die part having a back mold clearance in a die cavity. The die may have a generally cylinder-segment-shape. In an open position of the die, the blank may be inserted between the toothed mold clearance and the back mold clearance. The toothed die part and the back die part in a forging stroke for closing the cavity may then be moved in a closing direction to a closed position. The back radius of the back mold clearance may be larger than the unmachined radius of the blank.

A rack for a steering gear includes a toothed portion with a toothing extending along a longitudinal axis, and a generally cylinder-segment-shaped back opposite the toothing and having a back radius. A method for producing such a rack includes forming a cylindrical blank with an unmachined radius between a toothed die part having a toothed mold clearance and a back die part having a back mold clearance in a die cavity. The die may have a generally cylinder-segment-shape. In an open position of the die, the blank may be inserted between the toothed mold clearance and the back mold clearance. The toothed die part and the back die part in a forging stroke for closing the cavity may then be moved in a closing direction to a closed position. The back radius of the back mold clearance may be larger than the unmachined radius of the blank.

Provided is a method for producing a beryllium copper alloy ring including: providing a columnar forged material made of a beryllium copper alloy, opening a hole from a center of an upper surface of the columnar forged material in a direction parallel to a central axis of the columnar forged material to make a ring intermediate product, performing ring forging on the ring intermediate product, thereby expanding the hole such that a reduction ratio of 63% or more is achieved to make a ring-forged product, wherein the reduction ratio is specified by the following expression: P=100×(T−t)/T, wherein P represents the reduction ratio (%), T represents a thickness (mm) of the ring intermediate product, and t represents a thickness (mm) of the ring-forged product, and performing a solution annealing and a precipitation hardening on the ring-forged product to make the beryllium copper alloy ring.

A method is provided for manufacturing an outer ring of a constant velocity joint including an outer ring, an inner rotational member, a torque-transmitting rolling element, and a defining member. The outer ring includes: a first inner peripheral surface to which the defining member is attached; a second inner peripheral surface; and protrusions protruding radially inward of the first inner surface and the second inner peripheral surface so as to restrict axial movement of the inner rotational member and the rolling element. The manufacturing method includes: a plastic working step involving providing a base member; and a bottom removing step involving partially removing a bottom of the base member so as to form a through hole. The plastic working step further involves providing the second inner peripheral surface. The bottom removing step further involves providing the protrusions.

A steering rack (11a) meshes with a pinion rotatably driven by the input shaft (6) of a steering gear (5) constituting an automotive steering device. The steering rack (11a) is provided with a an axially extending rod part (15) of round cross section, and a plurality of rack teeth (16) formed on a radial one side surface of an axial portion of the rod part (15), the rack teeth (16) meshing with the pinion. At least one dummy tooth (42) is formed in portions that are axial parts of the rod part (15) and are adjacent to both axial sides of the plurality of rack teeth (16). The dummy tooth (42) has a tooth height less than the rack teeth (16) and does not mesh with the pinion.