Volumetric displacement selector for hydraulic motor with smooth selection

摘要

The positive displacement selector (110) for a hydraulic motor having at least two operating capacities and two or more main conduits (124, 126) consists of a slide valve with three channels (110A, 110B, 110C) which enable an establishment through the motor distribution ducts of a selective communication between the main conduits and the motor cylinders (102, 103). When the selector passes from its first to its second stable position it has an intermediate phase, maintained for a short period of time, in which the three channels are linked and the cross-section of the passages between the first and second channels and between the second and third channels is restricted.