Valves and valve actuation – Fluid actuated or retarded – Pilot or servo type motor
Patent
1994-12-21
1999-01-19
Walton, George L.
Valves and valve actuation
Fluid actuated or retarded
Pilot or servo type motor
251 46, 251 65, 25112915, 188299, 280707, 280714, F16K 3104, F16K 3108
Patent
active
058606319
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to pilot valves and more particularly to pilot valves for suspension control systems.
BACKGROUND OF THE INVENTION
A valve of this general type is disclosed in German patent specification 37 19 113. The above referenced valve which is intended for use as an absorber valve in a controllable vibration absorber to adjust the force absorbed by the vibration absorber, is substantially composed of a main stage (which is formed of a valve member interacting with a sealing seat and having a first, constant throttling cross-section) and a pilot stage configured in a second throttling cross-section in the valve member, and is infinitely variably controlled by means of a control needle operable by an electromechanical transducer.
One of the disadvantages of the above-referenced valve is its considerable overall length and its high manufacturing costs. Further, the dynamic characteristics of the above referenced valve are considered poor and rendering a valve of this type ineffective for application in suspension control systems.
Therefore, an object of the present invention is to provide a pilot valve of the type previously mentioned, the novel construction of which allows its overall length to be shortened and its manufacturing costs to be reduced. In addition, it is desirable to improve the dynamic characteristics of the valve and its function (minimum opening pressure for the main stage).
This object is achieved according to the present invention in that the pilot member has an annular design so that fluid discharges in a radial direction, and in that the valve member is a resiliently suspended plate. Such a valve design is very compact. The excellent dynamic characteristics of the valve is due to the annular design of the pilot member, rendering large flow cross-sections possible.
SUMMARY OF THE INVENTION
According to a favorable aspect of the present invention, the reliability in operation is augmented by the pilot member being guided on a preferably cylindrical guide element which is fixedly arranged in the valve housing.
Further, advantageously, radial pressure relief grooves are provided in the guide element which open into a slot provided between the pilot member and the guide element. This provision prevents a hydraulic jamming effect in this area.
According to another favorable aspect of the present invention, the valve member has an opening which receives an axial cylindrical extension of the guide element, the first throttling cross-section being formed by the annular slot confined between the valve member and the extension.
The manufacture of the valve according to the present invention is simplified in another embodiment of the invention by the first throttling cross-section being formed by an opening in the valve member which is preferably arranged centrally.
In another embodiment of the present invention, the slot provided between the pilot member and the guide element is properly supplied with filtered pressure fluid by a filter element which is connected upstream of the first throttling cross-section. This eliminates the risk of malfunction due to the imminent ingress of contaminants in this area.
In another favorable aspect of the present invention, the radially outwardly disposed annular fringe area of the plate is provided as a bending spring. Due to the one-part design of the valve member with its suspension or support, a spring without bias and with a great amount of rigidity is achieved.
To ensure that the function of the valve according to the present invention is preserved even upon failure of the electromechanical transducer (so-called fail-safe function), according to still another aspect of the present invention, the pilot member is suspended on a bending spring compressed in the valve housing. This provision is expedient in particular in connection with bidirectional transducers. The bending spring may be configured as a spring plate with apertures.
The risk of soiling is diminished to a still greater extent in another design of the va
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International Search Report for Application PCT/EP93/00576 filed 13 Mar. 1993.
International Examination Report for Application PCT/EP93/00576 filed 13 Mar. 1993 With Annexes and an English Translation.
ITT Automotive Europe GmbH
Lewis J. Gordon
Twomey Thomas N.
Walton George L.
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