PRESSURE CONTROLLED RADIAL PISTON PUMP

摘要

PROBLEM TO BE SOLVED: To solve the problem on a piston pump of a known pressure accumulation type which reduces back flow from a high pressure line by increasing the pressure of an oil in a cylinder at a bottom dead center where a cylinder transfers from low pressure suction to high pressure discharge, that its axial type involves the difficulty of storing a pressure accumulator in a compact form since there is a large residual capacity in the cylinder and its radial type involves an abrupt change in pressure to generate unfavorable impact for noises because there is a too small residual capacity at a top dead center in a discharge finishing stage. SOLUTION: Since there is a substantially small residual capacity in the cylinder, the radial piston pump requires the pressure accumulator applicable at the bottom dead center to have a smaller capacity than the axial type and it can incorporate a pressure accumulating cavity portion required for a fixed casing portion of a pintle change valve. The problem on the radial type that the abrupt change in pressure is produced since there is a too small residual capacity at the top dead center can be solved similarly by incorporating the pressure accumulating cavity portion for reducing pressure in a casing to make countermeasure for pulsation and noises without giving influences on the outline of the pump.