Patent ID: 7159506
Filing Date: 2007-01-09
Classification: F15B,F16D,G05D

Abstract:
1. A state detecting device for detecting a state of a load element receiving working fluid whose pressure is adjusted by an electromagnetic pressure-regulating valve equipped to a fluid pressure control circuit, wherein the electromagnetic pressure-regulating valve has a spool movable in accordance with an excitation state of a solenoid of the valve driven by a electrical drive circuit, an input port, a drain port, an output port, and a feedback chamber into which output pressure output from the output port thereof is fed back for regulating the output pressure by applying to the spool wherein an inter connecting state of the output port and one of the input port or the drain port is switched by the movement of the spool, and wherein the state detecting device includes an instruction value calculating portion which calculates the instruction value supplied to the electrical drive circuit to drive the electromagnetic pressure-regulating valve, a displacement detecting portion for detecting the displacement of the spool, and a load element state detecting portion for detecting the state variation of the load element on the basis of a displacement of the spool which is detected by the displacement detecting portion and is non-associated with the driving of the electrical drive circuit, when the instruction value supplied from the instruction value calculating portion is not varied.