Hydraulic unit esp hydraulic motor with adjustable stroke volume

摘要

The stroke volume of the unit (1) is binary adjustable. The unit has a control device (8), a servo piston (7) and a rotation rate recorder or pick up (5). Using the control device (8) the rotation rate is regulated on the basis of a rotation rate signal from the pick up (5). The rotation rate is regulated such that the piston (7) is controlled via a control member (6) in dependence on the frequency of a signal output from the control device (8), controlling the control member (6), for continuous stroke volume adjustment. The control device (8) may compare the rotation rate signal of the pick up (5) with a predetermined reference signal. A difference value signal resulting from the comparison is then provided to the control member (6) for its timed control. The control device may control the control member (6) to vary the stroke volume during a predetermined time period. During this variation, the control member (6) may be continuously time controlled on the basis of the resulting signals.