Patent ID: 8733192

Claim:
A high-load linear actuator, comprising: a driving mechanism, having a base and a motor rotated clockwise and counterclockwise, and the base having a supporting portion and an accommodating portion, and the supporting portion having a seat and a hollow cylinder formed and extended from the seat, and the accommodating portion having a ring body coupled to the hollow cylinder, and the motor being mounted onto the seat, wherein the accommodating portion further includes a cover plate covering the ring body at an open side of the ring body, a rear step is formed on a surface of the ring body at an internal side opposite to the open side, and a front step is formed on a side of the cover plate and at a position corresponding to the rear step; a worm shaft, protruding from the motor and passed into the hollow cylinder; a worm wheel assembly, having a worm wheel and two bearings for jointly supporting the worm wheel installed inside the ring body, wherein the worm wheel has a circular tooth flank engaged and transmitted with the worm shaft, a hollow axle is coupled to the circular tooth flank, a front containing groove and a rear containing groove are formed in the circular tooth flank to surround the hollow axle at two opposite sides of the circular tooth flank respectively, the two bearings are embedded in the front and the rear containing grooves and sheathed on opposite ends of the hollow axle respectively, one of the two bearings is installed and contained in between the front containing groove and the front step, and the other of the two bearings is installed and contained in between the rear containing groove and the rear step; a lead screw, passed through and coupled to the worm wheel, and actuated by the motor to produce a rotation; a telescopic pipe, sheathed onto the exterior of the lead screw and screwed with the lead screw; a retardation transmission mechanism including a driven gear, a gripper ring, a driven bushing, a plurality of rolling needles, an intermediate ring and a torque spring, and the driven gear being sheathed and coupled to the lead screw and passed and coupled to the worm wheel, and the gripper ring is sheathed and coupled to the driven gear for linking the worm wheel and the driven gear synchronously, and the driven bushing being sheathed and coupled to the lead screw and passed and coupled into the gripper ring, and the rolling needles being passed and coupled between the driven bushing and the intermediate ring, and the torque spring being provided for binding the external periphery of the intermediate ring by an elastic force; and an outer pipe, sheathed onto the exterior of the telescopic pipe, and the telescopic pipe being rotated and driven by the lead screw to linearly extend or retract with respect to the outer pipe.