| 摘要 |
1,142,852. Hydraulic reciprocating motors. BUTTERWORTH HYDRAULIC DEVELOPMENTS Ltd. March 8, 1966 [March 9, 1965], No. 9858/65. Heading F1A. A hydraulic motor comprises a differential piston 5, the smaller area end 9 being continuously subjected to pressure fluid through cylinder port 7, and the larger area end 19 being alternately connected to pressure and exhaust by a hydraulically actuated differential spool valve 12 in the piston. Movement of the spool valve is controlled by the co-operation of ports in the piston with lands formed in the cylinder. The arrangement is such that the port supplying fluid to move the spool valve in one direction does not fully close until the port supplying fluid to move the spool valve in the reverse direction has commenced to open thereby preventing stalling of the motor. The piston comprises two concentric parts with an interference fit, Fig. 1 (not shown). |
