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Pressure control system for suspension

  • US 5,024,459 A
  • Filed: 12/27/1989
  • Issued: 06/18/1991
  • Est. Priority Date: 12/28/1988
  • Status: Expired due to Term
First Claim
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1. Pressure control system for suspension comprisinga pressure source for supplying a fluid which is drawn from a reservoir to a high pressure piping under a high pressure which delivers a hydraulic fluid to a suspension which is adapted to extend and shrink in response to a pressure supplied thereto;

  • a pressure control valve including a line pressure port communicating with the high pressure piping, a low pressure port communicating with a low pressure, an output port for delivering a pressure to the suspension, a target pressure space communicating with the high pressure piping through an orifice, a spool responsive to a pressure from the output port applied to its one end to be driven in a direction to reduce a degree of communication between the line pressure port and the output port and to increase a degree of communication between the low pressure port and the output port and also responsive to a pressure from the target pressure space applied to its other end to be driven in a direction to increase a degree of communication between the line pressure port and the output port and to reduce a degree of communication between the low pressure port and the output port, a valve element for defining a degree of communication between the target pressure space and the low pressure, and electrical drive means for driving the valve element in a direction to increase/decrease the degree of communication;

    pressure detecting means for detecting a pressure in the high pressure piping;

    command means for commanding a pressure value to be applied to the suspension;

    correction means for correcting the pressure value from the command means in a manner dependent on the pressure detected by the pressure detecting means so as to increase the output value when detected pressure is low;

    and electrical energization means for electrically energizing the pressure control valve in accordance with the pressure value as corrected by the correction means so as to deliver a pressure corresponding to the pressure value to the suspension.

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