A ball screw includes a ball screw spindle, and a ball screw nut extending about the ball screw spindle. The ball screw nut has internal threading that corresponds with external threading of the ball screw spindle to define a raceway for rolling elements. The ball screw nut includes one or more bore holes extending from the exterior surface of the ball screw nut, and partially into the ball screw nut. The bore hole defines an end stop. A spring has one end that contacts the end stop, and another end that contacts one of the rolling elements.

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.

In a ball screw apparatus, a ball train including a plurality of main balls is housed in a raceway between a ball track of a ball nut and a ball track of a ball screw shaft. A coil spring housed in the raceway includes a first end that engages with an end of the ball train and a second end supported by a stopper (a first recessed portion, a protruding portion, or the like) of the ball nut. A stopper ball having a diameter larger than the diameter of the main ball is interposed between the stopper and the second end of the coil spring.

In a ball screw device, an inner peripheral rolling groove of a nut includes, between openings of mounting holes, a constant pitch circle diameter region where a pitch circle diameter is constant and gradually-changing pitch circle diameter regions where the pitch circle diameter gradually increases, in the ranges from opposite ends of the constant pitch circle diameter region to the respective openings. At least the constant pitch circle diameter region has a surface hardness greater than or equal to a predetermined value, among the constant pitch circle diameter region and the gradually-changing pitch circle diameter regions excluding edges at the boundaries between the respective openings and the inner peripheral rolling groove, and the edges at the boundaries between the respective openings and the inner peripheral rolling groove have a surface hardness less than the predetermined value.

An actuator is provided with means for controlling whether or not forces are transferred between a cylinder 12 (controlled by a motor of the actuator) and an output shaft 14. The output shaft 14 is located between the cylinder 12 and the control rod 18, 38. The cylinder 12 coaxially surrounds the output shaft 14, and the output shaft 14 in turn coaxially surrounds the control rod 18, 38. The control rod 18, 38 has one or more splines 20 on its outer surface facing the output shaft 12. The output shaft 14 has one or more holes 15, each containing a ball bearing 16.

The invention relates to mechanical engineering, and more particularly to a curved groove ball bearing mechanism, in which a pair of curved groove ball bearings without a retainer are symmetrically arranged to enable the conversion between the rotary motion and the reciprocating linear motion. The bearing mechanism includes an inner ring, a first outer ring, a second outer ring, a plurality of first steel balls and a plurality of second steel balls. The invention is capable of achieving the conversion between the rotary motion of the inner ring into the reciprocating linear motion of the first and second outer rings.

Provided is a bearing retainer (1) which has excellent oil resistance and impact resistance. The bearing retainer (1) retains a plurality of balls in such a manner that the balls are apart from each other. In a ball screw that is provided with a first member and a second member which moves relatively to the first member, the plurality of balls is arranged on one of the first member or the second member so as to be in contact with both of the first member and the second member, and rolling of the balls enables the relative movement. This bearing retainer (1) is formed from a resin composition that contains an elastomer component and a fluororesin which is mainly composed of vinylidene fluoride.

A tape-shaped product and a belt for a ball chain are provided. A tape-shaped product of synthetic resin includes a tape of a thermoplastic resin, and a preliminarily stretched fibrous member of a thermoplastic resin contained therein along longitudinally parallel edges or in proximity thereto of the tape. A belt for a ball chain, includes a tape-shaped product of synthetic resin formed by injection molding, together with a fibrous member as an insert of a resin of the same kind as that of the fibrous member so that the fibrous member is disposed along the longitudinal edges or in proximity thereto, ball-insetting holes are disposed at equal intervals, and ball-retaining projections are disposed around the holes.

Ball screw drives are disclosed. The ball screw may include a spindle having a threaded portion; a nut having a threaded portion, the threaded portions of the spindle and the nut together forming a ball channel; and a plurality of balls disposed in the ball channel to form a ball chain. Two or more intermediate springs may be disposed within the ball chain, each intermediate spring disposed between two balls in the ball chain. At least two of the two or more intermediate springs may have a different spring stiffness.