A ball screw assembly having a ball nut including a first end, a second end, a central bore, and a ball track defined by the inner surface, a ball screw shaft including an outer surface defining a ball track, the ball screw shaft being disposed in the central bore so that the ball tracks form a ball raceway, a first stopper disposed within the ball raceway, a plurality of main balls forming a ball train, the ball train being disposed in the ball raceway, and a main spring assembly disposed in the ball raceway between a first end of the ball train and the first stopper, wherein a spring constant of the first spring portion is greater than a spring constant of the second spring portion.

A ball-screw actuator includes a screw nut having a metal core and an over-molded plastic outer shell. The plastic outer shell includes features which would be expensive to manufacture in a single piece metal screw nut, such as an anti-rotation feature, an axial position control feature, and a lateral position control feature. The anti-rotation feature may take the form of an axial groove or of an axial ridge.

A door opening and closing device for vehicles of the present invention includes: a motor drive mechanism; a first housing that accommodates the motor drive mechanism; a spindle drive mechanism connected to the motor drive mechanism; and a second housing that is arranged coaxially with the first housing and relatively moves with respect to the first housing by the spindle drive mechanism. The spindle drive mechanism includes: a spindle connected to the motor drive mechanism; a spindle nut screwed with the spindle; a push rod fixed so as not to rotate relative to the spindle nut and provided with a protrusion on its outer periphery; and a guide tube in which a guide groove guiding the protrusion of the push rod in an axial direction is formed.

An adjusting drive for a steering column for a motor vehicle may include a threaded spindle that by way of an external thread engages in a spindle nut. The adjusting drive may also include a drive motor that is coupled to the threaded spindle or the spindle nut such that driving at least one of the threaded spindle or the spindle nut with the drive motor causes the threaded spindle and the spindle nut to rotate relative to one another. To reduce production complexity and improve functionality, the threaded spindle may have a core element that at least in portions is coaxially surrounded in a fixed manner by a threaded element that is configured from plastic and comprises the external thread.

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.

A leadscrew assembly includes a screw shaft along which is formed a first helical groove and a primary nut along which is form a second helical groove. The first helical groove and the second helical groove cooperate to define a track. The assembly also includes a secondary nut along which is formed a third helical groove. The first helical groove and the third helical groove cooperate to define a track with a nominal running clearance. A preload X is provided wherein when a load applied to the screw exceeds the predetermined preload, the secondary nut engages with the track such that load of the screw above preload X is transferred through the secondary nut and thus protecting the primary nut.

Leadscrew and nut actuators are described. The leadscrew and nut actuators include a leadscrew having an external thread and formed from a first material, a nut configured to receive the leadscrew, the nut having an internal thread and formed from a second material, and an insert arranged between the internal thread of the nut and the external thread of the leadscrew, the insert configured to transfer force between the external thread and the internal thread and prevent material contact between the leadscrew and the nut. The insert is formed of a third material different from the first material and the second material.

A motor rotor-blank assembly for a motor is provided. The rotor-blank assembly includes a rotor including a plurality of rotor anti-rotation features; and a blank having a hollow core and including a plurality of blank anti-rotation features corresponding to the rotor anti-rotation features, wherein the rotor anti-rotation features and the blank anti-rotation features work in conjunction to maintain the blank fixed within the rotor during rotation of the rotor.

This invention relates to an end cap return for a ball screw. The end cap uses tangential force from the sidewalls of the ball passage to roll the ball bearings sideways out of the leadscrew raceway rather than the typical protruding finger that picks the balls up directly. The end cap allows it to be advantageously fabricated with using additive manufacturing, making the end cap cost effective for use in custom ball screw assemblies. In some embodiments, the end cap may include an insert for certain portions of the end cap that can be easily and inexpensively replaced should the insert become worn.

A ball relief feature for a ball screw allows multiple turn ball circuits with reduced ball bearing stack-up within the ball screw assembly. Reliving bearing stack up allows for ball circuits having more turns without reducing the number of load carrying ball bearings of a typical ball nut. The ball relief feature reduces ball bearing stack-up by allowing the balls to re-distribute relative to one another and space themselves evenly in oversized portions of the ball circuit track other than the ball return mechanism.