A piston assembly includes a piston cross-member having a first end disposed opposite a second end. The piston assembly also includes a first cap disposed on the first end of the piston cross-member, and a second cap disposed on the second end of the piston cross-member. A slot is formed in the piston cross-member transverse to a length of the piston cross-member. An insert is disposed in the slot, wherein the insert is a wear article configured to contact a crank.

A piston assembly includes a piston cross-member having a first end disposed opposite a second end. The piston assembly also includes a first cap disposed on the first end of the piston cross-member, and a second cap disposed on the second end of the piston cross-member. A slot is formed in the piston cross-member transverse to a length of the piston cross-member. An insert is disposed in the slot, wherein the insert is a wear article configured to contact a crank.

A piston (10) for an internal combustion engine has discrete, cylindrical support surfaces (18, 24) for supporting a piston pin, wherein, between at least two support surfaces (18, 24), there is provided a recess (26) which has a radial depth of at least 10% of half of the distance between two opposite support surfaces.

The disclosure provides rotary machines that include, in one embodiment, a rotatable shaft defining a central axis A, the shaft having a first end and a second end. The shaft can have a first hub disposed thereon with a plurality of cavities. At least one contour is slidably received into an arcuate cavity in an exterior surface of the hub. The contour has a convex outer surface that cooperates with an inwardly facing curved surface of a housing to form a working volume.

The disclosure provides rotary machines that include, in one embodiment, a rotatable shaft defining a central axis A, the shaft having a first end and a second end. The shaft can have a first hub disposed thereon with a plurality of cavities. At least one contour is slidably received into an arcuate cavity in an exterior surface of the hub. The contour has a convex outer surface that cooperates with an inwardly facing curved surface of a housing to form a working volume.

A pump system includes a first pump and a second pump each having a plunger assembly. The plunger assembly includes a crosshead, a plunger, and a sleeve. The sleeve at least partially surrounds the plunger and an end of the crosshead. The sleeve is configured to create a fluid seal between the plunger and the crosshead.

A pump system includes a first pump and a second pump each having a plunger assembly. The plunger assembly includes a crosshead, a plunger, and a sleeve. The sleeve at least partially surrounds the plunger and an end of the crosshead. The sleeve is configured to create a fluid seal between the plunger and the crosshead.

A rocking journal bearing is provided in a piston coupling mechanism. The bearing includes a sleeve and a wristpin constructed with two sets of eccentrically-disposed bearing surfaces which alternate in accepting a compressive load during an operational cycle of the bearing. The sleeve includes a network of grooves to transport oil to the bearing surfaces. Lubricating oil flow through the bearing is minimized by limiting provision of pressurized oil from the wristpin to the network of grooves to portions of the cycle when one or the other of the sets of bearing surfaces receives the compressive load.

A rocking journal bearing is provided in a piston coupling mechanism. The bearing includes a sleeve and a wristpin constructed with two sets of eccentrically-disposed bearing surfaces which alternate in accepting a compressive load during an operational cycle of the bearing. The sleeve includes a network of grooves to transport oil to the bearing surfaces. Lubricating oil flow through the bearing is minimized by limiting provision of pressurized oil from the wristpin to the network of grooves to portions of the cycle when one or the other of the sets of bearing surfaces receives the compressive load.

A pivot bearing suitable for two connecting rods in at least one piston of an internal combustion engine having two crankshafts, includes radial bearing regions that are provided with bolt boreholes and are disposed on either side of a center longitudinal plane of the piston and delimit connecting rod ends, forming an intermediate space. The bearing regions are designed as cylinder bodies having a crucible-like cross-section, of which each cylinder body has a base wall and a bearing ring jacket. The base walls of the two cylinder bodies extend at a distance from each other, and the bearing ring jackets surrounding the base walls are guided away from the base walls in opposite directions. One or more connecting supports run between the base walls. The bearing ring jackets cooperate with the piston boreholes in a rotatably movable manner. The base walls are connected to bearing bushings which are oriented in the axial direction of the pivot bearing and into which the bolt boreholes are incorporated. The pivot bearing is made of a material that brings about a targeted low-weight construction of the pivot bearing, while offering high strength and low wear.