Patent attributes
A hydraulic piston pump includes a reciprocal piston disposed in a blind housing bore of a piston housing to generate a pumping action. To accommodate the piston, a piston cartridge is installed in each of the housing bores. The piston cartridge includes a piston sleeve having an inner sleeve periphery, a first outer sleeve periphery, and a second outer sleeve periphery. The inner sleeve periphery is configured to establish sliding contact with the piston. The first outer sleeve periphery has a first outer sleeve diameter that is larger than a second outer sleeve diameter of the second outer sleeve periphery. To seal against the blind housing bore, a liner cap having a cylindrical liner wall and an axial liner cover is disposed over the first outer sleeve periphery. The axial liner cover abuts a housing bore ceiling of the blind housing bore and can receive hydraulic fluid there through.