A rotary seal comprising: a shaft with a chromium oxide coating provided at a seal contact area; wherein said coating has a hardness of at least 55 Rockwell-C. The coating may have a surface roughness parameter (Ra) of between 0.2 and 0.4 circular. The coating may have a thickness of at least 0.1 mm. The coating layer forms part of a rotary seal with a flexible seal element that is biased into contact with the surface of the coating. The flexible seal element may be biased against the shaft by a spring to increase the pressure of the flexible seal element against the coating. The coating is preferably deposited by a plasma spray process.

An actuator includes a threaded spindle and an internally threaded component screwed onto the threaded spindle. The component includes a plastic element having a first axial end and a second axial end and an interior having a width and a radially inwardly projecting flange at the first axial end, and the flange has an inner diameter less than the width of the interior. A metal element, such as a nut, is fixedly mounted in the interior of the plastic element, and the internal thread of the nut has a maximum diameter greater than the inner diameter of the flange.

A profiled nut (1) of a screw drive includes a sleeve (3) produced from sheet steel, has a non-cuttingly formed rolling profile (4) on the inner circumference for rolling contact with rolling bodies and is hardened in a heat treatment method at least in the region of the rolling profile (4). An inner lateral surface of the sleeve (3) having the rolling profile (4) is hardened and has a higher Rockwell hardness. An outer lateral surface of the sleeve (3) is designed such that it can be welded and has a lower Rockwell hardness.

The present disclosure relates to a hollow-type BLDC motor of a power sliding device of a vehicle seat, and a nut coupled to a lead screw is injection-molded with a plastic and installed only on a longitudinal partial section of the inner diameter of a rotor, a magnet of the rotor is produced in an integrated cylindrical shape having no gap between magnetic poles, and a skew angle is given on a boundary line between the magnetic poles, thereby reducing noise and vibration.

A spindle rod for a spindle device includes a threaded rod (2) with a threaded portion (3) extending along a spindle axis (S) and a coupling part (7) for coupling the threaded rod (2) to a drive or a gear of a drive device. The coupling part (7) is integrally connected to a first end (2a) of the threaded rod (2). The coupling part (7) has a connecting portion (7a) provided for connecting the threaded rod (2) at a first end (2a) facing the threaded rod. The connecting portion (7a) has a bead-shaped thickening.

A nut assembly for use with lead screws is provided. The nut assembly includes a nut member and an adjustment arrangement that can independently adjust the biasing of flexible fingers of the nut member.

An adjustment drive for a steering column of a motor vehicle may include a threaded spindle having an external thread, engaging with a corresponding internal thread of a spindle nut. A thread tooth of the external thread and a thread groove of the internal thread have corresponding axially sliding thread flanks that are braced against each other. At least one thread flank comprises at least one recessed lubricant uptake.

An object of the present invention is to provide a ball screw having a structure in which a screw shaft and a nut satisfy required performance and having improved durability, a method for manufacturing the ball screw, a power steering device, and a method for manufacturing the power steering device.

A ball screw according to the present invention includes: a nut made of a steel substrate having an inner peripheral surface on which a female screw is formed; a screw shaft that is combined with the nut and is made of a steel substrate having an outer peripheral surface on which a male screw facing the female screw is formed; and a plurality of balls arranged between the female screw and the male screw. A surface of the nut in contact with the ball and a surface of the screw shaft in contact with the ball each have carburized layers. A carbon concentration in the carburized layer of the nut is higher than a carbon concentration in the carburized layer of the screw shaft.

A screw element of a ball screw mechanism includes a lead screw which, at an axial end, is joined to a rod element using a friction welding process. In order to improve the friction-welded joint, prior to the friction welding process, the lead screw has a circumferential groove on the end face facing the rod element.

A worm (40) according to an embodiment is a worm made of resin and formed by injection molding. The worm includes a gear portion (40a), a cavity (40c) having an axis being a longitudinal axis (40d) of the worm being formed at the gear portion, and a top portion (40b) formed at a first end portion of the gear portion in a direction of the longitudinal axis. A plurality of recesses (40e) including a hole portion communicating with the cavity are formed at the top portion in a radial direction, and are located on an outer peripheral portion side of the gear portion with respect to the cavity.