Abstract: A saddle bearing liner (30) for a variable displacement axial piston pump (10) includes two axially-spaced apart bearing surfaces (62, 64) with an offset central section (54) integrally joining them. A hollow projection (80) extends radially from the convex side of the pressure bearing section (50) and is received with a recess (82) of the housing (12) to locate the liner (30). The liner (30) has radially extending ledges (70, 72) which mate with surfaces (74, 76) of the housing (12) to inhibit skewing of the bearing liner (30) relative to the axis of the bearing surfaces (62, 64). The projection (80) is hollow and opens to the bearing surface (62) so that presurrized fluid from the housing (12) can be injected between the bearing surface (62) and the mating surface (22) of the swashblock (20). The projection (80) also prevents the liner (30) from rotating about the bearing surface axis.

Abstract: A saddle bearing liner (30) for a variable displacement axial piston pump (10) includes two axially-spaced apart bearing surfaces (62, 64) with an offset central section (54) integrally joining them. A hollow projection (80) extends radially from the convex side of the pressure bearing section (50) and is received with a recess (82) of the housing (12) to locate the liner (30). The liner (30) has radially extending ledges (70, 72) which mate with surfaces (74, 76) of the housing (12) to inhibit skewing of the bearing liner (30) relative to the axis of the bearing surfaces (62, 64). The projection (80) is hollow and opens to the bearing surface (62) so that presurrized fluid from the housing (12) can be injected between the bearing surface (62) and the mating surface (22) of the swashblock (20). The projection (80) also prevents the liner (30) from rotating about the bearing surface axis.

Abstract: The disclosure relates to a pump having (a) a wobble plate, (b) a barrel, (c) a pair of piston assemblies reciprocated in the barrel by the wobble plate, and (c) a mechanism retaining the piston assemblies in contact with the wobble plate. In the improvement, the mechanism comprises a yoke member contacting the piston assemblies and a support member mounted to the barrel. The support member has a concave surface and the yoke member has a convex surface contacting the concave surface for bearing support. The support member coacts with the yoke member and permits oscillation of such yoke member in a plane substantially coincident with the barrel central axis. The new hold-down mechanism may be "cascaded" in that the pump may also include another pair of piston assemblies and a second yoke member contacting the second pair of piston assemblies. A bearing component, e.g., a spherical ball, is interposed between the yoke members.

Abstract: The disclosure relates to a pump having a wobble plate, at least one piston assembly reciprocated by the wobble plate, and a mechanism retaining the piston assembly in contact with the wobble plate. In the improvement, the mechanism includes a hold-down plate having a number of radially-extending retention fingers. Each finger extends into a fill opening of a separate piston assembly and retains such assembly in contact with the pump wobble plate. The piston shoe is maintained in sliding contact with the wobble plate; that is, separation of the piston assembly from the wobble plate is thereby substantially prevented.