Patent ID: 6570282
Filing Date: 2003-05-27
Classification: F16H,H02K

Abstract:
A cylinder servo motor comprising:a servo motor having a rotor and a stator; a cylinder servo motor main unit which is connected to a rotary shaft of the rotor of the servo motor by way of a ball screw nut and which has a ball screw shaft, the ball screw shaft moving in an axial direction; a rotation sensor for detecting a rotary position of the servo motor; and control means for controlling the rotation sensor and the servo motor, wherein the cylinder servo motor main unit, the rotation sensor, and the control means are mechanically integrated; the rotor of the servo motor is constituted of the rotary shaft and a permanent magnet, the rotary shaft being rotatably supported by a load-side bearing supported by a load-side bracket and by a non-load-side bearing supported by a non-load-side bracket, at least the load-side end of the rotary shaft being released, a through hole being formed in the rotary shaft so as to extend in an axial direction, and the permanent magnet being disposed opposite the stator fixed to the rotary shaft with a predetermined clearance therebetween; the ball screw nut is constituted of a ball circulation mechanism and is mounted on a load-side shaft end of the rotary shaft; the ball screw shaft is screw-engaged with the ball screw nut so as to become movable in only the axial direction such that a non-load-side shaft end of the ball screw shaft is housed in the through hole of the rotary shaft and such that a load-side end of the ball screw shaft protrudes from the load-side bracket; a rotation portion of the rotation sensor is coupled to a non-load-side portion of the rotary shaft protruding from the hole formed in the non-load-side bracket and is covered with a rotation sensor cover; the control means is disposed on a part of the non-load-side bracket distant from the stator; and the control means and the rotation sensor cover are covered with a chassis to be fastened to the-non-load-side bracket.