Abstract: First, the pressure of oil within an oil passage in a control valve device is measured. Then, an amplitude and period of pressure fluctuations are detected on the basis of an obtained measurement result, and an oil vibration state or an oil non-vibration state is diagnosed. In this case, when the amplitude is greater than a reference amplitude value and when the period is less than a reference period value, the oil vibration state is diagnosed. Further, a duration time of the oil vibration state is determined on the basis of a diagnostic result. Then, when the oil vibration state continues for a period greater than or equal to a reference time, warning information is output. In this way, warning information is output stepwise in accordance with occurrence or continuation of oil vibration.

Abstract: First, the pressure of oil within an oil passage in a control valve device is measured. Then, an amplitude and period of pressure fluctuations are detected on the basis of an obtained measurement result, and an oil vibration state or an oil non-vibration state is diagnosed. In this case, when the amplitude is greater than a reference amplitude value and when the period is less than a reference period value, the oil vibration state is diagnosed. Further, a duration time of the oil vibration state is determined on the basis of a diagnostic result. Then, when the oil vibration state continues for a period greater than or equal to a reference time, warning information is output. In this way, warning information is output stepwise in accordance with occurrence or continuation of oil vibration.

Abstract: Disclosed is a hydraulic control module that can be downsized. The hydraulic control module includes an upper control valve, a lower control valve, and a wiring plate. The upper and lower control valves each include an oil path having a groove portion. A sandwich structure is employed so that the wiring plate is sandwiched between the upper and lower control valves. The wiring plate has a groove portion or a through-hole that is in communication with the at least one of the groove portion of the upper control valve and the groove portion of the lower control valve.

Abstract: It is a solenoid valve used in hydraulic control. Inside a body 4, a clip plate 11 is provided at the side of an inlet 5. The clip plate 11 is formed integral by a circular support portion 12 and three retaining pawls 13 extending toward its center. On the other hand, a filter 21 of synthetic resin is formed integral by an outer frame portion 22 encircling the inlet 5, an inner frame portion 23 bisecting it and filter portions stretched therebetween. Further, a retaining convex portion 25 projecting toward the inlet 5 is provided at an intermediate portion of the inner frame portion 23. The inner frame portion 23 is elastically deformed to move the retaining convex portion 25 toward the side of the inlet 5 so that it is retained by the three retaining pawls 13 of the clip plate 11. The shape can be achieved wherein the filter 21 does not project so much from the body so that the overall size of the solenoid valve can be reduced.