| 摘要 |
PROBLEM TO BE SOLVED: To provide a multispeed fluid pressure operating device for avoiding cavitation and noises during a shift, and a shifting operation control method for the same. SOLUTION: A gerotor motor 10 has motor valve means 19, 43 for distributing fluid between fluid volume chambers to be expanded 33E or contracted 33C and a shift valve spool 61 for performing either a normal low-speed and high-torque (LSHT) mode or a high-speed and low-torque (HSLT) mode. In the HSLT mode, some of volume chambers are used as recirculating volume chambers 33R. Furthermore, motor has a fluid resupplying flow path 89 for supplying fluid from a system charge pump 73 to each recirculating volume chamber 33R, and it also has a control valve 83 for avoiding cavitation during shift from the HSLT mode to the LSHT mode. COPYRIGHT: (C)2004,JPO
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