HYDRAULIC AXIAL-PISTON DEVICE WITH FEATURES TO ENHANCE EFFICIENCY AND POWER-DENSITY

摘要

An axial piston device configuration that includes a drive shaft, a piston block, pistons, a constant velocity joint assembly, a drive plate coupled to the constant velocity joint assembly, a swash plate, shoes, and piston rods may be provided. The piston block has an interior that is coupled to the drive shaft via a first torque transmitting mechanical interface. The constant velocity joint assembly includes multiple components, at least one of which is coupled to the drive shaft via a second torque transmitting mechanical interface.

主权项

1. An axial piston device comprising:
a drive shaft that rotates about a longitudinal drive axis; a piston block having an interior coupled to the drive shaft by a first torque transmitting mechanical interface such that the piston block rotates with the drive shaft about the longitudinal drive axis, the piston block defining a plurality of cylinders; pistons positioned within the cylinders, the pistons being reciprocally movable within the cylinders; a constant velocity joint including an inner race, an outer race and balls positioned between the inner and outer races, the inner race being coupled to the drive shaft by a second torque transmitting mechanical interface such that the constant velocity joint rotates with the drive shaft about the longitudinal drive axis, the balls being configured to transfer torque from the inner race to the outer race, and the balls being configured to allow the outer race to pivot relative to the inner race and the drive shaft; a drive plate coupled to the outer race of the constant velocity joint such that the drive plate rotates with the constant velocity joint about the longitudinal drive axis, the drive plate defining a plurality of shoe pockets, and the drive plate being mounted to pivot with the outer race relative to the drive shaft; a swash plate configured to pivot with the drive plate and the outer race relative to the drive shaft, the swash plate not being rotatable with the drive shaft; shoes positioned within the shoe pockets and carried with the drive plate, the shoes providing a bearing interface with the swash plate; piston rods having first heads mounted to universally pivot within the pistons and second heads mounted to universally pivot within the shoes, the piston rods defining longitudinal fluid passages that provide fluid communication between the cylinders and the shoes; and wherein fluid bearings are defined between the shoes and the swash plate at the bearing interface, wherein the shoes define shoe fluid passages that provide fluid communication between the longitudinal fluid passages of the piston rods and the fluid bearings such that the fluid bearings are pressurized by fluid pressure from the cylinders.