Actuator with ring gear and method of manufacturing same

Abstract

A fluid-powered rotary actuator having a body with a cylindrical interior sidewall portion. A drive shaft extends generally coaxially within the body and is supported for rotation relative thereto. The shaft has a grooved, outwardly facing circumferential sidewall portion positioned within the body. A ring gear is positioned generally coaxially within the body and extends about the shaft with an annular space therebetween. The ring gear has a grooved, inwardly facing circumferential sidewall portion. The ring gear is formed as a separate part from the body and the ring gear grooved sidewall portion is formed prior to positioning of the ring gear in the body. The ring gear is fixedly attached to the body to prevent rotation therebetween by a weld between the ring gear and the body interior sidewall portion. A stop member is engaged by the ring gear. The stop member is axially located within the body to limit movement of the ring gear toward the body first end during assembly of the ring gear in the body. The stop member may be a stop shoulder formed integral with the body interior sidewall portion or a snap ring. In the stop shoulder embodiment, the ring gear is welded to the stop shoulder. A piston sleeve is mounted for reciprocal axial movement within the body in response to the selective application pressurized fluid thereto. An annular sleeve portion thereof is positioned generally coaxially within the body in the annular space between the ring gear and the shaft and extends about the shaft. The sleeve portion has a grooved, inwardly facing circumferential sidewall portion engaging the shaft grooved sidewall portion and a grooved, outwardly facing circumferential sidewall portion engaged with a ring gear grooved sidewall portion to translate axial movement of the piston into clockwise or counterclockwise relative rotational movement between the shaft and the body.