| 摘要 |
PCT No. PCT/US80/01194 Sec. 371 Date Sep. 12, 1980 Sec. 102(e) Date Sep. 12, 1980 PCT Filed Sep. 12, 1980 PCT Pub. No. WO82/01046 PCT Pub. Date Apr. 1, 1982.Flow-pressure compensated valves are employed in servo-systems for variable displacement pumps to maintain discharge pressure above a minimum pressure level and above the load pressure in a fluid actuator, during the working range of the pumps. In addition, such systems may also include a horsepower limiting valve for ensuring that the rating or predetermined range of horsepower consumption of the pumps is not exceeded. Prior art systems normally continually bleed-off pump discharge or load pressure signals when such horsepower requirements are exceeded to, thus, effect an undesirable horsepower loss in the system. In addition, control systems of this type normally cannot be packaged in modular form and are not adapted for use with pumps of various capacities and sizes. The improved fluid circuit (10) of this invention includes a horsepower limiting arrangement (39) for blocking communication of an actuator pressure signal (PA) to an actuating chamber (37) of a servo-system (24) for a variable displacement pump (11) and to vent the actuating pressure signal (PA) in response to a pressure control signal (PC) which indicates that the pump (11) has exceeded its predetermined range of horsepower consumption.
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