| 摘要 |
PROBLEM TO BE SOLVED: To provide an abnormality detection method of a flow rate control valve which can detect, as an abnormality, the thermal expansion of a valve main body and a spool accompanied by a rise of an oil temperature of a working fluid, or a motion failure of the spool resulting from the bite-in or the like of impurities (contamination) which mixedly intrude into the working fluid in the valve main body, and a motion failure resulting from a temporal change, in the flow rate control valve which controls a spool position by a servomotor.SOLUTION: In a flow rate control valve 16 which moves or holds a position of a spool 35 arranged in a flow rate control valve main body 30 to an arbitrary position by a servomotor 33 via a motion conversion mechanism 31 which converts a rotation motion to a linear motion, and controls a flow rate of a working fluid circulating in the flow rate control valve main body 30, the abnormality detection method of the flow rate control valve monitors the rotation torque of the servomotor 33 during a moving operation of the spool 35, and when the rotation torque exceeds a preset upper limit, determines that an abnormality has occurred in the flow rate control valve 16.SELECTED DRAWING: Figure 4 |
