A linear actuator includes a screw shaft comprising a screw thread and having a longitudinal axis A, a nut movable along the screw shaft from a retracted position to an extended position, and a plurality of rollers movable with the nut. Each roller includes a cylindrical surface configured to roll along one or more flanks of the screw thread, such that rotation of the screw shaft causes the rollers to roll along the flank(s) so that the nut translates in an axial direction along the screw shaft. The screw thread has a variable lead angle. The actuator can be part of a power door opening system of an aircraft.

A linear actuator includes a screw shaft comprising a screw thread and having a longitudinal axis A, a nut movable along the screw shaft from a retracted position to an extended position, and a plurality of rollers movable with the nut. Each roller includes a cylindrical surface configured to roll along one or more flanks of the screw thread, such that rotation of the screw shaft causes the rollers to roll along the flank(s) so that the nut translates in an axial direction along the screw shaft. The screw thread has a variable lead angle. The actuator can be part of a power door opening system of an aircraft.

A spot welding apparatus (10) according to the present invention includes: a circular cylindrical cam (12) having an outer circumferential surface, in which a spiral-shaped large lead cam groove (12a) inclined at a steep angle and a spiral-shaped small lead cam groove (12b) inclined at a gentle angle are formed; and a pressurizing shaft (13) including a plurality of rollers (R1, R2) insertable into the respective cam grooves (12a, 12b) and configured to move along an axis of rotation of the circular cylindrical cam (12) when the circular cylindrical cam (12) rotates. When the rollers (R1, R2) are inserted into the large lead cam groove (12a), a roller (R1, R2) located at one end side of a row comes into contact with one of two sides surfaces of the cam groove (12a) and a roller (R1, R2) located at another end side of the row comes into contact with the other one of the two side surfaces of the cam groove (12a), and when the rollers (R1, R2) are inserted into the small lead cam groove (12b), each of the rollers (R1, R2) comes into contact with at least one of one side surface and the other side surface of two side surfaces of the cam groove (12b).

A linear actuator includes: a screw shaft that has a screw thread and a longitudinal axis A and a nut movable along the screw shaft from a retracted position to an extended position. The actuator also includes a plurality of rollers movable with the nut, each of which includes a cylindrical surface configured to roll along one or more flanks of the screw thread, such that rotation of the screw shaft causes the rollers to roll along the flank(s) so that the nut translates in an axial direction along the screw shaft. The screw thread includes one or more detents (e.g., grooves) configured to lock the nut in one or more axial positions.

A load sensor to be used in an electromechanical brake system includes a flange member capable of deflecting when receiving, at a load receiving portion, a load from the axially front side; a support member capable of supporting the flange member from the axially rear side, at a support portion displaced from the load receiving portion in a radial direction orthogonal to the axial direction; and a displacement detecting mechanism configured to detect the amount of relative movement between the flange and support members. A variable detection sensitivity mechanism enables the relative movement amount with respect to the change of the load applied to the flange member to be larger in a low load range in which the load is equal to or lower than a predetermined load value than in a high load range in which the load is higher than the predetermined load value.

In one embodiment, an actuator has a roller, a helical track, and at least one track follower. The roller has a cylindrical body that has a first end, a second end that is offset from the first end along a central axis, and a cylindrical outer surface that extends from the first end to the second end. The helical track is disposed around the cylindrical outer surface in a helical pattern. The at least one track follower can be attached to a load, and rides along the helical track when the roller is rotated about the central axis so as to translate the load along an axial direction that is substantially parallel to the central axis. In some embodiments, the roller has an internal motor that is disposed within the cylindrical body.

An actuator includes a housing, a first nut in the housing, a second nut in the housing, and a threaded spindle screwed into the first nut and the second nut. The first nut exerts a first force in a first direction on the threaded spindle, and the second nut exerts a second force in a second direction on the threaded spindle, the first direction being different than the second direction.

A load sensor used in an electromechanical brake system is provided. The load sensor includes a flange member capable of deflecting when receiving, at a load receiving portion, a load from the axially front side; a support member capable of supporting the flange member from the axially rear side, at a support portion displaced from the load receiving portion in a radial direction orthogonal to the axial direction; a displacement detecting mechanism configured to detect the amount of relative movement between the flange and support members; and a variable detection sensitivity mechanism enabling the relative movement amount with respect to the change of the load applied to the flange member to be larger in a low load range in which the load is equal to or lower than a predetermined load value than in a high load range in which the load is higher than the predetermined load value.

A linear actuator comprises a roller screw mechanism guided in rotation with respect to a structure by two angular-contact ball bearings, the roller screw mechanism comprising rollers interposed between an endless screw and two tapped rings which are joined together in rotation and free in translation. Each tapped ring is secured to an inner ring of a ball bearing. The linear actuator further comprises a single preloading device capable of applying load between two outer rings of the angular-contact ball bearings respectively, thereby simultaneously allowing the loading of the roller screw mechanism and the rotational guidance of the roller screw mechanism with respect to the structure.

The present disclosure relates to a screw drive with an element having a thread, at least one planet and a holder, wherein the at least one planet is held by the holder and rolls along the threads of the thread of the element and the holder moves linearly along the thread of the element relative to the element. The at least one planet of the screw drive is formed by a bearing which engages with its outer ring or with its inner ring in the thread of the element via an angular section.