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.

Provided is a power transmission device including a housing and a ball screw device including a nut housed in the housing. The device includes a screw shaft passing through the nut, and balls disposed between the nut and the screw shaft. The device also includes a first bearing and a second bearing that are disposed to be adjacent to each other in a center axis direction parallel with a center axis of the nut between the housing and the nut; and a preload applying member constituted of an elastic body and configured to apply preloads to the first bearing and the second bearing. The first bearing and the second bearing respectively include outer rings that are fitted to the housing and separated from each other in the center axis direction, and the first bearing and the second bearing are disposed to be a face-to-face combination.

A rotary mechanical transmission, includes: a containment structure, a first rotary element, connected to a drive unit to define a mechanical power input unit and rotatable about an axis. The transmission also includes a fixed guide and a second rotary element, rotatable about said axis and defining a power output unit. A connecting element extends along the axis and couples to the first rotary element by a first threaded connection. The connecting element is also coupled with one of either the fixed guide and the second rotary element by a second threaded connection, and with the other of the fixed guide and the second rotary element by a linear guide parallel to the axis. The first threaded connection and second threaded connection have different pitches in such a way as to vary the angular speed between the connecting element and the first rotary element.

A pressure supply unit for a brake system including a booster body that defines an axially extending cylinder. A piston is slideable within the cylinder. The piston defines a bore that receives a spindle. The spindle is rotationally fixed and axially moveable for providing the axial movement of the piston. A motor is positioned about the spindle and is configured to axially translate the spindle and piston. A ball and socket joint connects the piston and spindle while accommodating pivoting movement of the spindle. The ball and socket joint includes a ball at a front end of the spindle and a socket in the bore of the piston which receives the ball.

An electromechanical brake pressure generator for a hydraulic braking system of a vehicle, including a threaded drive system for converting a drive-side rotary motion into a translatory motion for brake pressure generation. The system includes a spindle rotatable via an electric motor, a spindle nut cooperating with a thread of the spindle so the spindle nut is axially displaceable with a rotation of the spindle and a brake fluid is loadable or relievable, and a housing which, together with the spindle nut, forms an anti-twist protection which secures the spindle nut against twisting during rotation of the spindle. The spindle nut forms at least one spindle nut reference surface, which cooperates with at least one stop surface, which is stationary with respect to the housing, in a relief end position of the spindle nut in such a way that an instantaneous axial position of the spindle nut is determinable therefrom.

A power transmission device including a housing and a ball screw device including a nut, a screw shaft, and a plurality of balls. The device includes a pulley device including a driving pulley configured to be driven by receiving power transmitted from a power source, a driven pulley fixed to the nut, and a belt wound around outer peripheral surfaces of the driving pulley and the driven pulley. The device also includes a first bearing and a second bearing disposed between the housing and the nut in a center axis direction parallel with a center axis of the nut; and a preload applying member configured to apply preloads to the first bearing and the second bearing. The first bearing and the second bearing are respectively disposed on both sides of the driven pulley to be a face-to-face combination, and each of the first bearing and the second bearing includes an outer ring engaged with the housing.

A ball screw assembly includes a screw shaft along which is formed a first helical groove; a nut along which is form a second helical groove; the first helical groove and the second helical groove cooperating to define a track, a plurality of balls arranged in the track and configured to move along the track in response to relative motion between the screw shaft and the nut such that rotational motion of the screw is translated to linear motion of the nut via the balls and vice versa. The assembly also includes a bypass shoe arranged between the nut and the track and spaced from the track by a predetermined preload X, wherein when a load applied to the nut exceeds the predetermined preload, the bypass shoe engages with the track such that motion of the screw is transferred to motion of the nut via the shoe and bypasses the balls.

A ball screw drive (10) including a threaded spindle (12) and a spindle nut (14) which at least partially coaxially encloses the threaded spindle (12) and has a stop at an axial end face (18). A multiplicity of balls can circulate in the space (16) between the threaded spindle (12) and the spindle nut (14). A radial stop element (22) is connected to the threaded spindle (12) in a force-fitting manner and adapted to interact with the complementary axial end face (18) of the spindle nut (14). A bearing element is provided for receiving a first longitudinal end of the spindle nut (12). The radial stop element (22) and the bearing element are designed in combination as an integral bearing/stop element (24) which has two anti-rotation features (26, 28).

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.

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.