An articulated coupling is provided for a piston sealing device for a piston which includes a fixed skirt and a sliding skirt interconnected by a mechanical inter-skirt connection for axially compressing a continuous extensible segment under the action of a sliding skirt spring, the coupling replacing, on the one hand, the fixed skirt by a ball-joint skirt and providing, on the other hand, a troncospherical piston end which cooperates with a skirt troncospherical bearing surface provided on the ball joint skirt while an articulation unit interposed between the inter-skirt mechanical connection and the piston and/or between the connection and the sliding skirt.

An opposed piston engine has a driveshaft with a spaced apart cams mounted thereon. Each cam has a circumferential cam shoulder of a curvilinear shape selected to enhance flow through intake and exhaust ports. The curvilinear shape may be a segmented polynomial shape forming lobes which lobes are asymmetrical so that the lobe wavelength distance from a first trough to the lobe peak of an ascending shoulder portion of the lobe is greater than the lobe wavelength distance from the peak to a second trough of a descending shoulder portion of the lobe. Opposing cam shoulders may be shaped so as to always be converging or diverging from one another.

An opposed piston engine has a driveshaft with at least two combustion cylinders serially aligned along a center cylinder axis so as to be coaxial, where the center cylinder axis is parallel with but spaced apart from the driveshaft axis. A cam is disposed between adjacent combustion cylinders, as well as adjacent the outermost end of each combustion cylinder in order to reciprocatingly drive piston pairs disposed in each combustion cylinder.

A hydrostatic axial piston machine includes a housing, a cylinder barrel, and a drive shaft, which are connected together and mounted in the housing so as to rotate jointly about a first axis. The machine also includes a swash plate mounted in the housing so as to pivot about a second axis to adjust a swept volume of the machine. The machine further includes a hydraulic actuating apparatus, which has an actuating piston that delimits an actuating chamber. The machine also includes a regulating valve attached to a flange face of the housing. The regulating valve has connections situated in the flange face that are used to communicate hydraulic fluid to and from the actuating chamber. The flange face is arranged obliquely so as to enclose an angle with the second axis that is greater than 0 and smaller than 90.

A hydraulic device includes a shaft mounted in a housing rotatable about a first axis of rotation. The shaft has a flange extending perpendicularly to the first axis. A plurality of pistons is fixed to the flange. A plurality of cylindrical sleeves cooperates with the pistons to form respective compression chambers of variable volume. The cylindrical sleeves are rotatable about a second axis of rotation which intersects the first axis of rotation by an acute angle such that upon rotating the shaft the volumes of the compression chambers change. Each piston has a piston head including a circumferential wall of which the outer side is ball-shaped and the inner side surrounds a cavity. Each of the pistons is fixed to the flange by a piston pin having a piston pin head including a circumferential outer side facing the inner side of the circumferential wall of the piston head.

A method for manufacturing an at least sectionally spherical-cap-shaped recess on a drive shaft for a hydrostatic axial piston machine includes whirling of the recess and heat treatment of the recess to form a wear layer. A drive shaft for a hydrostatic axial piston machine includes at least one recess manufactured according to the method. A hydrostatic axial piston machine includes a drive shaft with at least one recess manufactured according to the method.

A rotatable piston assembly for a reciprocating piston type hydraulic machine includes a rotatable piston configured for a controlled rotation and configured to reciprocate within a cylinder bore of the reciprocating piston type hydraulic machine.

A rotatable piston assembly for a reciprocating piston type hydraulic machine includes a rotatable piston configured for a controlled rotation and configured to reciprocate within a cylinder bore of the reciprocating piston type hydraulic machine.

A cylinder block for use in an integrated drive generator has a shaft portion with a relatively small outer diameter and a cylindrical body portion having a larger outer diameter than the shaft portion, and said cylindrical body portion formed with a plurality of piston chambers, said cylindrical body portion extending from a first end to a second end, said second end being provided with cylindrical ports leading into said piston chambers and said cylindrical ports having a third end and a fourth end wherein a ratio of a first distance from said first end to said fourth end to a second distance from said first end to said second end being between 0.91 and 0.93. A generator and a method are also described.

A piston in a liquid-pressure rotating device in which pistons are arranged at a cylinder block rotatable together with a rotating shaft, includes: a cylindrical peripheral wall main body portion including a hollow portion, an opening portion formed at one end of the body portion and communicating with the hollow portion; a lid portion welded to an inner peripheral surface of the opening portion sealing the hollow portion and including an outer surface formed as a pressure receiving surface which receives liquid pressure; and a stress reducing portion provided on an inner peripheral surface of the body portion, the inner peripheral surface in contact with or close to an end portion of a welded portion formed between the opening portion and the lid portion, the end portion located at the hollow portion side, the stress reducing portion configured to reduce stress acting on the end portion of the welded portion.