A rack may include a toothed portion having a toothing, and a shaft portion having a threaded portion with a coaxial thread that has a thread length in an axial direction of a longitudinal axis. Separate segments comprising at least one in each case bar-shaped toothed segment and one shaft segment are provided, are aligned on the longitudinal axis, and are connected to one another at a joint. A method for producing the rack may involve providing a shaft raw material piece having a piece length that is a multiple of a shaft segment length, generating a thread that is continuous in a longitudinal direction on the shaft raw material piece across a multiple of the thread length to produce a threaded semi-finished product, cutting to length a threaded segment from the threaded semi-finished product, providing a toothed segment, and joining the threaded segment to the toothed segment.

A method for producing a rack for a steering gear may involve providing a toothed segment and a shaft segment aligned on a longitudinal axis and connecting the segments by axial joining faces by friction welding at a welding joint. For friction welding, the joining faces may be brought into frictional contact by an initial friction force, the segments may be rotated relative to one another, the joining faces may be mutually compressed by way of a contact pressure force until a predefined joining path has been reached by way of a welding force 10 to 20 times the initial friction force, thermal input friction may be performed by an input force 5 to 12 times the initial friction force, and the segments may be moved toward one another in an axial direction by the predefined joining path. The segments may be held in position without friction.

The present disclosure relates to a seat height adjustment device for adjusting the height of a seat cushion in relation to a seat frame, in particular, an upper rail, the seat height adjustment device comprising an actuating device, which may be, in particular, an electric motor, with a toothed pinion driven by the actuating device, and a toothed gear rack, the toothed gear rack comprising a hinge end for hinging onto the vehicle seat, and a front end including a gear rod region engaging with the toothed pinion, for adjusting the hinge end upon rotation of the toothed pinion. The present disclosure provides that the toothed gear rack is hot forged, the toothed gear rack comprises, between the hinge end and the gear rod region, a reinforced region, and the reinforced region comprises a profile.

A rack for a steering gear of a motor vehicle may include a toothed portion having a toothing, and a shaft portion. Separate segments comprising at least one in each case bar-shaped toothed segment and one shaft segment are provided, are aligned on a common longitudinal axis, and are connected to one another at a joint. The method may involve providing a raw material piece having a piece length that is a multiple of a segment length, thermally continuously hardening the raw material piece across a multiple of a segment length to produce a hardened semi-finished segment product, cutting to length a hardened segment from the hardened semi-finished segment product, providing a further segment, and joining the hardened segment to a further segment.

A rack bar blank for a steering system is provided. The rack bar blank includes a first region having a circular cross-section. The rack bar blank also includes a second region having a flattened surface along a length thereof, the flattened surface present prior to formation of teeth.

A rack bar blank for a steering system includes a first region having a first diameter. The rack bar blank also includes a second region having a second diameter that is greater than the first diameter prior to formation of teeth on the second region and a ball screw thread on the first region.

A rack bar includes a shaft member having a toothed section. The toothed section has a plurality of rack teeth, and extends over a portion of an entire length of the shaft member along a longitudinal direction of the shaft member. The shaft member has a grinding-finished outer peripheral surface extending over the entire length of the shaft member including the toothed section. A method for manufacturing the rack bar includes forming the toothed section by plastic working and grinding the outer peripheral surface to improve shape accuracy.

Rack bar 10 for transmitting a steering operation to steered wheels while converting a rotational movement of a pinion shaft rotatably connected to a steering wheel into an axial movement, the rack bar being formed by conducting a die forging process on a material having an approximately circular cross section. A pair of face width-enlarged portions 15 is provided at both ends that rack teeth 14 have in face width direction. With this, it becomes possible to ensure face width dimension W of rack teeth 14 larger than outer shape S of a circular cross section of rack main body 13 (material), which results in an improvement of a contact gear ratio between the pinion teeth and the rack teeth.

To provide a method for manufacturing a rack that can reduce the manufacturing cost, the method comprises the following processes. An intermediate material 18a having a concave groove 42y in part in the radial direction of the outer circumferential surface that extends in the axial direction and is recessed inward in the radial direction is obtained. A plurality of rack teeth 10z are formed on an opposite surface to the concave groove 42y with respect to the radial direction of the outer circumferential surface of the intermediate material 18a by pressing the teeth-forming concave and convex section 28 that have a concave and convex configuration with respect to the axial direction in a state where the portions on both sides of the concave groove 42y of the outer circumferential surface of the intermediate material with respect to the circumferential direction are constrained and the inner surface of the concave groove 42y is not constrained.

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.