Tsubakimoto Chain Company

Satoshi Morishima

Yutaka Kobayashi

Kyoshi Kawamoto

Takaki Tsuruzono

A linear actuator includes a screw shaft rotatably supported within a housing with play in motion in the axial direction of the screw shaft, and a cushioning stopper disposed between the housing and the screw shaft and elastically deformable to absorb a force acting from the screw shaft to the housing when the screw shaft is forced to move relative to the housing in the axial direction within the range of the play at an abutment of a rod with an obstacle or stopper. When the rod is stopped moving, the motor current increases with the degree of elastic deformation of the cushioning stopper. An overload sensor cuts off the supply of power to an electric motor when excessive current in the motor is detected.

Linear actuator with abutment stoppers

A linear actuator includes two axially opposed bearings with built-in one-way clutch assembled in a housing member with respective outer races secured to the housing member such that respective directions in which inner races of the bearings are locked against rotation are opposed to each other, a ball bearing shaft relatively and rotatably supported on the inner races of the bearings with bearing bushings disposed between the ball screw shaft and the respective bearings, and two load transmitting collars fixed on the ball screw shaft. When the ball screw shaft is subjected to a thrust load applied from a ball nut in a direction to retract the ball screw shaft, one of the inner race is locked against rotation to thereby exert a braking torque to the corresponding load transmitting collar via an associated friction collar. Alternatively, when the ball screw shaft is subjected to a thrust load tending to extend the ball screw shaft, the other inner race is locked against rotation to thereby exert a braking torque to the corresponding load transmitting collar via an associated friction collar. Thus, rotation of the ball screw shaft under the effect of the thrust load in either direction can be avoided.

Growing community of inventors

Osaka, Japan

Satoshi Morishima