Proportional electro-hydraulic pressure control valve
First Claim
1. In a proportional electro-hydraulic relief valve, said relief valve comprising:
- a valve body,a hydraulic fluid inlet port in said valve body,a hydraulic fluid outlet port in said valve body,a pressure detecting fluid path in said valve body filled with hydraulic fluid,valve means arranged between said ports to control a pressure at said hydraulic fluid inlet port, andproportional plunger means slidably mounted in said valve body for causing application of a force proportional to an input current for setting a controlled pressure to act on said valve means,said valve means including a sensor holder having a pressure sensor mounted in a sensor receiving hole defined by said valve body for detecting a hydraulic fluid pressure in said pressure detecting fluid path and outputting the same as an electric signal, a pressure sensing portion of said pressure sensor being positioned so as to be exposed to said pressure detecting fluid path, said sensor holder being positioned and fixed in said valve body by a plug-and-snap assembly for preventing said pressure sensor from slipping out of position under the action for hydraulic pressure, and notches formed in said plug-and-snap assembly for accommodating signal lead wires from said pressure sensor.
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Accused Products
Abstract
A proportional electro-hydraulic pressure control valve incorporates a pressure sensor in its valve body and the hydraulic fluid pressure in a pressure detecting fluid path provided in the valve body is delivered as an electric signal output by the pressure sensor. The pressure detecting fluid path is connected to a hydraulic fluid inlet port directly or through a restrictor or alternately the fluid path is connected to a pressure detecting port separated from both of the hydraulic fluid inlet port and a hydraulic fluid outlet port. The electric signal output from the pressure sensor is utilized to provide a numerical display of the controlled pressure or to effect the feedback control of a solenoid drive current through a closed loop.
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Citations
15 Claims
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1. In a proportional electro-hydraulic relief valve, said relief valve comprising:
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a valve body, a hydraulic fluid inlet port in said valve body, a hydraulic fluid outlet port in said valve body, a pressure detecting fluid path in said valve body filled with hydraulic fluid, valve means arranged between said ports to control a pressure at said hydraulic fluid inlet port, and proportional plunger means slidably mounted in said valve body for causing application of a force proportional to an input current for setting a controlled pressure to act on said valve means, said valve means including a sensor holder having a pressure sensor mounted in a sensor receiving hole defined by said valve body for detecting a hydraulic fluid pressure in said pressure detecting fluid path and outputting the same as an electric signal, a pressure sensing portion of said pressure sensor being positioned so as to be exposed to said pressure detecting fluid path, said sensor holder being positioned and fixed in said valve body by a plug-and-snap assembly for preventing said pressure sensor from slipping out of position under the action for hydraulic pressure, and notches formed in said plug-and-snap assembly for accommodating signal lead wires from said pressure sensor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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Specification