A seal member for a ball screw device, which is fixed to an axial end surface of a nut member of the ball screw device and is configured to seal a gap between the nut member and the screw shaft, the seal member including: a plurality of base plates which each have a through hole having an inner diameter larger than an outer diameter of the screw shaft; a spacer plate, which is sandwiched between two base plates adjacent to each other, and has a seal accommodation hole having an inner diameter larger than an inner diameter of a through hole of the base plates; and a seal plate, which has a shaft-fitting hole corresponding to a sectional shape of the screw shaft in a direction perpendicular to an axial direction, and is arranged in the seal accommodation hole of the spacer plates.

The present invention suppresses an increase in pressure of internally contained lubricating oil and reduces leakage of the lubricating oil. This actuator is provided with: an accumulator which has a gas compartment at the top filled with gas, and in which a lubricating oil is contained under the gas compartment; a housing internally provided with the accumulator; a shaft of which one end side is contained in the housing and another end side is disposed outside the housing, and which is moveable in an axial direction; and an oil seal disposed between a first opening portion which is formed in the accumulator and through which the shaft penetrates, and the shaft. The housing has formed therein a pipe channel providing communication between a space on the side opposite to the inner side of the accumulator with respect to the oil seal and the gas compartment of the accumulator.

A ball screw adapted to detecting coolant liquid includes a screw, a nut, a plurality of sealing members, a sensor, a signal processing unit and a cover. The nut includes a main body and an end surface, and a through-hole and a flow channel are disposed on the main body. The nut is threadedly disposed on the screw via the through-hole. A plurality of openings are disposed on the end surface, and the openings communicate with the flow channel. The sealing members are disposed in the plurality of openings. The sensor is disposed on one of the sealing members to detect a pressure of the coolant liquid and output an original signal. The signal processing unit is electrically connected to the sensor to receive the original signal and convert the original signal to a digital signal. The cover is disposed on the sensor and fixed to the nut.

A screw nut on which a pulley is mounted is capable of promoting reductions in the size and weight thereof. The screw nut includes: an outer ring; and a nut rotatably assembled to the outer ring via a first rolling element. The nut includes: a nut body having a screw groove in an inner surface thereof; and a recirculation component provided at an end portion of the nut body in an axial direction, the recirculation component having a turn-around path for recirculating a second rolling element rolling along a screw groove. A pulley to be mounted on the nut is fitted on an outer surface of the nut body, and is brought into contact with an end surface of the nut in the axial direction. The pulley is mounted on the end surface of the nut with a fastening member.

Disclosed herein is a screw assembly comprising an internal re-circulating path for re-circulating lubricant fluid between a threaded screw shaft and seals provided at the ends of the screw assembly via internal chambers provided within the seals and passages formed within the nut. Also disclosed are seals for use within such assemblies.

A seal member for a ball screw device, which is fixed to an axial end surface of a nut member of the ball screw device and is configured to seal a gap between the nut member and the screw shaft, the seal member including: a plurality of base plates which each have a through hole having an inner diameter larger than an outer diameter of the screw shaft; a spacer plate, which is sandwiched between two base plates adjacent to each other, and has a seal accommodation hole having an inner diameter larger than an inner diameter of a through hole of the base plates; and a seal plate, which has a shaft-fitting hole corresponding to a sectional shape of the screw shaft in a direction perpendicular to an axial direction, and is arranged in the seal accommodation hole of the spacer plates.

A screw drive includes a spindle and a nut with a nut body. The nut body has at least one hole for a fastening member that is configured to enable the screw drive to be fastened on a higher-level subassembly or on a higher-level construction component. The at least one hole is further configured as a coolant duct of a coolant path. In one embodiment, an interior space between the nut body and the spindle is configured as a coolant duct.

A ballscrew actuator comprises a ballnut having at least one first helical groove formed on a radially inner surface and defining an axis (X), a ballscrew disposed along the axis (X) within the ballnut, the ballscrew having at least one second helical groove formed on a radially outer surface and opposed to the first helical groove so as to form at least one helical raceway and a plurality of balls or rolling elements disposed in the at least one helical raceway. The ballscrew is movable relative to the ballnut between a stowed position and a deployed position. The ballscrew comprises a ballscrew bore extending axially therein. A lubrication piston is mounted for sliding movement within the ballscrew bore and divides the ballscrew bore axially into a lubricant receiving portion and a pressurising portion.

A screw nut on which a pulley is mounted is provided, the screw nut capable of promoting reductions in the size and weight thereof. A screw nut includes: an outer ring; and a nut rotatably assembled to the outer ring via a first rolling element. The nut includes: a nut body having a screw groove in an inner surface thereof; and a recirculation component provided at an end portion of the nut body in an axial direction, the recirculation component having a turn-around path for recirculating a second rolling element rolling along a screw groove. A pulley to be mounted on the nut is fitted on an outer surface of the nut body, and is brought into contact with an end surface of the nut in the axial direction. The pulley is mounted on the end surface of the nut with a fastening member.

A linear actuator (1) comprising an electric motor (20), a transmission (40), a spindle (80) being connected to the transmission (40), a spindle nut (81) being arranged on the spindle (80), a housing (10), an outer tube (3) being connected to the housing (10), and an inner tube (2) being connected to the spindle nut (81). The spindle nut (81) and the inner tube (2) are guided inside the outer tube (3). The transmission (40) including a transmission housing (41), a transmission input end and a transmission output end positioned opposite the transmission input end. A coupling (30) including a first coupling part (32) being connected to the output end of the transmission, a second coupling part (34) being connected to the end of the spindle and a coupling member (36) disposed between the first and second coupling parts (32, 34) and slidably engaged with the first and second coupling parts (32, 34).