RADIAL PISTON TYPE MULTI-CYLINDER HYDRAULIC PUMP OR MOTOR

摘要

1,272,013. Cams. HITACHI Ltd., and KEIHIN HITACHI ENG. CO. Ltd. 27 May, 1969 [10 June, 1968], No. 26826/69. Heading F2K. [Also in Division F1] In an inwardly-acting radial piston multicylinder hydraulic pump or motor, the pistons have rolling means for engaging a cam surface which is profiled so that the torque generated by each piston as it moves from a cam crest to a cam trough varies so as to follow a curve in which the torque increment up to the maximum torque point is less than the torque decrement beyond the maximum torque point. Formulµ and graphs are given for deriving the cam shape to achieve constant overall torque, when the torque curve is in the form of an assymetric trapezoid. The cam may also be profiled to provide dwell sections before the torque increment section and/or after the torque decrement section. Conditions are given for achieving a constant overall torque for even and odd numbers of pistons.