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US 4,788,489 AGranted
Position sensor for use in variable height automotive suspension or the like
AssigneesNissan Motor Co., Ltd., Atsugi Motor Parts Company, Limited
InventorsHiroshi Kobayashi, Yoshinobu Kida, Toshiro Ichikawa
Life of this patent
Estimating the term…
Abstract
In order to ensure a reliable body earth and insulate a capacitance type position sensor from external noise, an electrically conductive tube is insulatingly mounted within an electrically conductive housing. The capacitance developed between the tube and a piston rod which is reciprocally arranged therein is measured while the rod and the conductive body are electrically connected. By soundly grounding the rod a secure ground for the housing is established.
Claims14
A position sensor device comprising:
- a housing containing a first fluid of known dielectric constant, said housing being formed of an electrically conductive material;
- an outer elongated first hollow member insulatingly supported within said housing in a contact free relationship therewith and exposed to said first fluid, said outer hollow member being formed of an electrically conductive material;
- an inner hollow member, said inner hollow member being disposed within said outer hollow member in a contact free and electrically isolated relationship therewith, said inner hollow member being filled with a second fluid,
- a shaft reciprocatingly disposed in said inner hollow member in manner to define a clearance therebetween, said shaft being formed of an electrically conductive material and supported within said inner hollow member in a contact free and electrically insulated relationship therewith;
- means for establishing simultaneous electrical connection between said housing, said inner hollow member and said shaft and with a source of electrical ground;
- and
- a circuit for measuring capacitance developed in a first capacitor developed between said inner and outer hollow members and a second capacitor developed between said housing and said outer hollow member.
4 more elements
A position sensor device comprising:
- a housing containing a fluid of known dielectric constant, said housing being formed of an electrically conductive material;
- a first elongate hollow member insulatingly supported within said housing in a contact free relationship therewith and immersed in said fluid, said first hollow member being formed of an electrically conductive material;
- a shaft reciprocatingly disposed in said first hollow member in manner to define a clearance therebetween, said shaft being formed of an electrically conductive material and supported within said first hollow member in a contact free and electrically insulated relationship therewith;
- means for establishing simultaneous electrical connection between said housing and said shaft with a source of electrical ground;
- a circuit for measuring capacitance developed between said shaft and said first hollow member;
- a second hollow member, said second hollow member being disposed within said first hollow member in a contact free and electrically isolated relationship therewith, said second hollow member being filled with said fluid and connected with said source of electrical ground by said electrical connection establishing means, said first and second hollow members defining a first capacitor and said housing and said first hollow member defining a second capacitor;
- and
- an air gap defined between said first and second hollow members, said air gap containing an insulating layer of air, said air gap being constantly communicated with the ambient atmosphere by a passage structure which includes a vent open to said ambient atmosphere.
5 more elements
Dependencies are inferred from the claim text.