The assembly may include a cylinder block, a plurality of pistons, and a holding element, the holding element extending over all or part of the outer periphery of the cylinder block. The holding element may include a plurality of guide portions, each partially blocking a recess of the cylinder block so as to come into contact with a planar end of the crown of a piston to guide in the translation of each piston in their respective recesses. The holding element may include two indexing means cooperating with two indexing means of the cylinder block so as to hold the holding element under a traction force when positioned around the cylinder block.

The assembly may include a cylinder block, a plurality of pistons, and a holding element, the holding element extending over all or part of the outer periphery of the cylinder block. The holding element may include a plurality of guide portions, each partially blocking a recess of the cylinder block so as to come into contact with a planar end of the crown of a piston to guide in the translation of each piston in their respective recesses. The holding element may include two indexing means cooperating with two indexing means of the cylinder block so as to hold the holding element under a traction force when positioned around the cylinder block.

A plurality of guide shafts which are disposed parallel to an input/output shaft (a first input/output shaft, a second input/output shaft) are assembled in a case body which holds a cylinder in which first and second piston sets, move reciprocally. A first guide bearing, which abuts both side surfaces of a first piston body and receives only lateral pressure generated by the reciprocal movement, and a second guide bearing, which abuts both side surfaces of a second piston body and receives only lateral pressure generated by the reciprocal movement, are assembled coaxially and separated in an axial direction on each guide shaft.

A motor (10) to be driven by a pressurized fluid includes a manifold (16) with an arcuate surface (20) defining a valve opening (22) surrounded by a sealing surface. A cylinder (26) has an aperture (30) cooperating with the arcuate surface (20). The cylinder (26) is pivotally mounted so as to be pivotable between a neutral state in which the aperture faces the sealing surface, an inlet state in which the aperture (30) is in fluid connection with the valve opening (22), and an exhaust in which the aperture (30) is in fluid connection with a drainage volume. A piston (34), deployed in the cylinder (26), is driven to extend by pressure within the cylinder. The piston is linked to a crank (36) so that rotation of a crankshaft (38) causes a cyclic motion of the piston (34) and cylinder (26) from the inlet state for an extension power stroke of the piston (34), through the neutral state and to the exhaust state for a return motion of the piston (34). The pivot axis of the cylinder, preferably implemented using a pivot axle (32), is located between the crankshaft axis and the arcuate surface (20).

A rotary cam radial engine formed of two primary components engaged at a mid section to allow for an easy repair to the vehicle. The device features a body having radially oriented apertures; and a plurality of pistons in a respective reciprocating engagement, within each respective said cylinder. The pistons are driven by low pressure fluids and/or a vacuum and the engine being formed of two main components can be taken apart without tools for maintenance and reconfiguration.