Medical devices in accordance with various embodiments of the present invention employ one or more coaxial screw gear sleeve mechanisms. In various embodiments, coaxial screw gear sleeve mechanisms include a post with a threaded exterior surface and a corresponding sleeve configured to surround the post, the corresponding sleeve having a threaded interior surface configured to interface with the threaded exterior surface of the post and a geared exterior surface. A drive mechanism can be configured to interface with the geared exterior surface of the sleeve, causing the device to expand.

A ball screw nut for a ball screw drive includes a sleeve element which is formed as a sheet metal part and has a thread which is formed for the largest part as a load channel, wherein a relief section formed within the thread extends from the load channel at least slightly radially outwards and adjoins a deflection channel.

A method for monitoring remaining useful life (RUL) of an actuation system in a vehicle that includes receiving position data of the actuation system from a position sensor, maintaining a total distance traveled for the actuation system, and calculating the RUL of the actuation system. The calculating includes estimating force data using an output variable estimator, determining motor torque, weighing the estimated force data using a confidence level, predicting a total life of the actuation system based on the weighted force data, and comparing the predicted total life with the total distance traveled to determine the remaining useful life.

In the ball screw device, the circulation path that returns balls from the end point to the start point of the load path includes a return path, scooping paths, and connecting paths. The scooping path has an arc-shaped center line that is curved outward in the radial direction as going toward the reference imaginary flat plane including the center axis of the screw shaft and the center line of the return path in the circumferential direction. The connecting path is arranged on the reference imaginary flat plane and includes a straight path having a linear center line extending in a direction orthogonal to the center axis of the screw shaft. When the radius of curvature of the center line of the scooping path is R1, the scooping angle is θ, and the entire length of the straight path is S, R1 cos(90°−θ)+S is made larger than the diameter of the balls.

The ball screw device includes: a screw shaft having an N number (N is an integer equal to or larger than 2) of rolling grooves having the same lead; balls configured to roll in the rolling grooves; and a nut member, which is assembled to the screw shaft through intermediation of the balls, and includes one or a plurality of endless circulation paths configured to circulate the balls around the screw shaft. Each of the endless circulation paths of the nut member includes: an N number of load portions, which are configured to allow the balls to roll thereon while bearing a load, and correspond to the N number of rolling grooves, respectively; and an N number of no-load portions, which each couple adjacent ones of the load portions, and are configured to allow the balls to move between the N number of rolling grooves.

Provided is a power steering apparatus capable of reducing a maximumly generated stress on an output pulley. An output pulley of a power steering apparatus includes a fastening target portion around a screw insertion hole of a hub portion. When a boundary portion between the hub portion and a winding and hanging portion is defined to be a portion where a minor angle, among relative angles formed between a tangential line of an inner surface of the output pulley and a rotational axis of a nut in an axial cross section of the output pulley that passes through the rotational axis of the nut, gradually reduces from a nut-rotational-axis side toward a radially outer side to then reach 45 degrees, the fastening target portion is a region that is located on an inner side in a radial direction with respect to the boundary portion and overlaps a head portion of a screw in a radial direction of the screw.

Steering actuators for vehicles are described herein. An example actuator includes a rack to be coupled to a knuckle of a vehicle, a ball nut coupled to the rack, a ring gear coupled to the ball nut, and a motor with a pinion engaged with the ring gear. The motor is to rotate the ball nut, via the pinion and the ring gear, to move the rack linearly.

A ball screw device has a screw shaft; a nut; a circulation part; and balls; a housing concave groove provided on the outer circumferential surface of the nut and linearly extending in the axial direction and opening to end surfaces on both outer sides in the axial direction of the nut, a circulation part arranged inside the housing concave groove, and the circulation part being prevented from displacing toward the outer side in the radial direction and displacing in the circumferential direction with respect to the nut by engaging an engaging convex portion of a fixing portion provided in the end portion on each of both outer sides in the axial direction of the circulation part with an engaging recess portion provided in the end portion of each of both outer sides in the axial direction of the housing concave groove.

An electric actuator for a steering system is adapted to control an angle of steered wheels on a vehicle to adjust a direction of travel of the vehicle. The electric actuator includes a housing assembly, an electric motor, and an actuation unit. The housing assembly is arranged around the electric motor and the electric motor is coupled with the actuation unit and configured to cause an actuator rod of the actuation unit to move relative to the housing assembly.

Provided is a ball screw device which enables easy production and assembly of a nut member and formation of an endless circulation path for balls in the nut member with high accuracy. The nut member includes a plurality of nut components arranged in a superposed manner along an axial direction of a screw shaft. At a boundary portion between the nut components which are adjacent to each other, a raceway path for balls extending around a periphery of the screw shaft is formed. A joining surface of each of the nut components used for joining with another one of the nut components includes: a raceway forming surface which is annularly formed around the through hole; and an abutment surface for joining which is formed on an outer side in a radial direction with respect to the raceway forming surface.