A spindle nut (S) for a ball screw is conventionally designed as a hollow cylinder with a central-symmetrical middle longitudinal axis (Z). The spindle nut has an internal thread, which is designed as a ball groove (K) arranged on the cylinder inner surface. Pairs of load-relief bores (B) serve as substantially cylindrical channels for guiding the balls out of and into the ball channel (K) through the wall of the spindle nut. Each load-relief bore (B) is distinguished by a generatrix (L), which has an intersection point (C) with the thread base line of the ball channel (K) and constitutes the geometric continuation of the traveling path of a ball from the ball channel (K) into the load-relief bore (B). A tangent (T) to the cylinder surface (G) runs in a parallel manner at a spacing a >0 to the generatrix (L), both T and L being perpendicular to a common normal (R) to the middle longitudinal axis (Z).

A steering system includes a steered shaft, a ball screw nut, balls, a housing, a rolling bearing, and a snap ring configured to prevent the rolling bearing from detaching from the ball screw nut. The rolling bearing includes double-row rolling element arrays, an outer ring, a first inner ring, and a second inner ring. The ball screw nut has a receiving portion. The snap ring contacts a side face of the second inner ring to push the second inner ring toward the receiving portion via the first inner ring. A resistance force received from the second outer peripheral fitting surface when the second inner ring moves in the axial direction in a state in which detachment of the rolling bearing is not prevented by the snap ring is smaller than a pushing force with which the snap ring pushes the second inner ring.

According to an aspect of some embodiments of the present invention there is provided a piston mounted on and fixedly fastened to a ball screw nut, the nut threaded onto a ball screw. By mechanically rotating the piston and preventing the ball screw from rotating, the balls screw nut rotates, thereby raising or lowering the ball screw, thereby raising or lowering the piston, thereby raising or lowering a casing, for example a bollard, mounted on the piston. The casing may be raised or lowered by attaching a handle to the piston and rotating the handle.

An external circulation ball screw includes: a screw shaft; a nut sleeved on the screw shaft and including a through hole having an opening end; and a return member mounted on the nut, and including a return groove having a return section and a continuation section, one end of the return section connected to the through hole including a connecting end which abuts against the opening end. The opening end and the connecting end are non-tangentially connected, the return section circles around a reference point, the outer wall surface of the return section is arc-shaped and centered on the reference point, a distance between the outer wall surface and the reference point is a radius of curvature, and the radius of curvature is greater than or equal to 1.2 times the ball diameter, but is less than or equal to 1.5 times the ball diameter.

A planetary roller screw drive for an actuator of a rear-axle steering system of a motor vehicle, including a planetary roller support which accommodates the planetary rollers and is connected to a drive sleeve for rotation therewith, which drive sleeve is driven rotatably about the screw spindle and is mounted rotatably on a machine part by an axial angular contact roller bearing which is arranged coaxially with respect to the drive sleeve and of which the rollers are in rolling contact with angled-bearing raceways which are inclined with respect to a plane arranged transversely with respect to the axis of rotation of the drive sleeve.

A ball screw assembly having a ball screw nut including an outer surface, an inner surface defining 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 two ball tracks form a ball raceway, a first stopper disposed at a first end of the ball screw nut within the ball raceway, a plurality of main balls forming a ball train disposed in the ball raceway, a main spring assembly disposed in the ball raceway between a first end of the ball train and the first stopper, and a strain sensing element affixed to a flat surface portion defined by the outer surface of the ball screw nut.

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.

An improved steering shaft assembly is provided. The steering shaft assembly further includes an output shaft that is rotatable with respect to the input shaft. The output shaft includes a rotary valve portion and a longitudinal portion. The steering shaft assembly further includes a torsion bar coupled to the input shaft and coupled to the output shaft distal from the input shaft. The steering shaft assembly further includes a mid-coupler extending around about the longitudinal portion of the output shaft and adapted to cooperate with the rotary valve portion of the output shaft. The steering shaft assembly further includes a screw mechanism extending about the longitudinal portion of the output shaft and adapted to cooperate with the mid-coupler. The screw mechanism is adapted to move laterally relative to the output shaft to maintain transfer of power from between output shaft and the screw mechanism despite misalignments therebetween.

Described is a mechanical transmission (T) comprising a containment structure (1) housing a roto-translational element (2), extending along an axis of rotation (X) and comprising a first and a second threaded portion (3, 4), a rotary element (5) connected or connectable to a drive unit to define a mechanical power input unit and equipped with a first thread (8) designed to engage rotatably with the first threaded portion (3) to the roto-translational element in such a way as to define a first threaded connection, a fixed guide (9) having a second thread (14) designed to engage with the second threaded portion (4) of the roto-translational element (2) in such a way as to define a second threaded connection, and a translating element (10), translating along the axis (X) and defining a power output unit. The translating element (10) is connected to the roto-translational element (2) for translating at the same linear speed as the roto-translational element (2). The roto-translational element (2) is thus simultaneously coupled to the rotary element (5) and to the fixed guide (9) respectively by means of the first and second threaded connections. These connections have different pitches in such a way as to vary the angular speed between the roto-translational element (2) and the rotary element (5).

A screw pair including inner walls of screw holes in a working nut and a pre-tightening nut with sensor groups including a plurality of displacement sensors capable of measuring a value of a gap between an inner and outer wall of a screw in a diameter direction of the screw hole, the group includes four displacement sensors evenly distributed in a circumferential direction of the screw hole, every two displacement sensors are paired and symmetrical about a center axis, and projections of a plurality of sensor groups in an axial direction overlap the screw; and an adaptive excitation coil is mounted to each displacement sensor, which is capable of attracting the screw in a measurement direction of the adaptive displacement sensor, and a magnetic force of the coil attached is adjustable to change the value of the gap, so that axes of the screw, working nut, and pre-tightening nut coincide.