Abstract: A hydraulic or pneumatic oscillating piston motor has a housing (1), a driven shaft (2) mounted in the housing for rotation and an oscillating piston (3) that is fixed to the shaft. The piston has two lever arms (49,8) having pressure areas of different size, which arms are sealed with respect to the housing (1) dividing the housing (1) into two working spaces (4,5) into which a pressure medium can be introduced. The oscillating piston (3), actuated by the pressure medium, is free to oscillate back and forth through a maximum angle of rotation which is determined by means of a stop (38) and the housing. The first lever arm is designated in the form of a bushing (49) whose shell surface along its external periphery is at least partly surrounded by a coaxial shell seal (64). This seal has uniformly distributed, rib-like sealing lips (75) along its periphery and interacts with a opposite surface (9) attached rigidly to the housing (1). The maximum angle of rotation of the oscillating piston (3) is at least 180.

Abstract: A fluid driven oscillating piston motor is made up of a housing, a shaft mounted in the housing so that it may be oscillated, and a piston running out from the shaft for turning it. The piston divides a space in the housing into two working spaces that are alternately pressurized and relieved of pressure so that the piston is turned through an angle as limited by an adjustable system of stops. The housing is split up into a shell and a lid therefor. Inner faces of the shell engaged by the piston are free or joins because it is made by molding or pressure casting. The shell and the lid are held together by a band with a clamping effect. The piston is joined to the shaft by means of a bush with internal splines fitted into splines of the shaft. A piston seal placed round the shaft is molded in one piece on the oscillating piston.