Magnetic-type of analog distance sensor having a hall effect sensing element

• US 4,665,362 A
• Filed: 02/27/1985
• Issued: 05/12/1987
• Est. Priority Date: 03/23/1984
• Status: Expired due to Fees

• Current Assignee: Wabco Westinghouse Fahrzeugbremsen GmbH
• Original Assignee: Wabco Westinghouse Fahrzeugbremsen GmbH
• Inventors: Muller, Michael, Abel, Joachim, Neuhaus, Detlev, Hesse, Karl-Heinz, Lichtenberg, Wolfgang
• Primary Examiner(s): Strecker, Gerard R.
• Application Number:
  US06/706,204
• Time in Patent Office: 804 Days
• Field of Search: 324/207, 324/208, 324/235, 324/251, 338/32 R, 338/32 H, 336/130, 336/134, 340/870.31, 340/870.32, 340/870.33, 318/647, 318/653
• US Class Current: 324/207.2
• CPC Class Codes: G01D 5/147 influenced by the movement of a third element, the position of Hall device and the source of magnetic field being fixed in respect to each other

Abstract

The invention relates to an analog non-contact distance sensor which includes a fixed stationary annular magnetized armature. The stationary armature member is provided with an air gap into which is disposed an element which is sensitive to a magnetic field. The moving portion is a rod-shaped magnetic core member which can be inserted into the annular armature member. Depending on the depth of insertion of the core member, the amount of diversion of the magnetic field from the air gap of the armature is controlled. Consequently, the magnetic sensing element emits an electrical signal which corresponds to the distance travelled by the movable core member.

Claims

1. An analog distance sensor comprising, a tubular support member having a central annular bore and upper and lower rims, a stationary annular magnetic field generating armature member surrounding said tubular member between said upper and lower rims, said stationary annular magnetic field generating armature member having an air gap providing said armature member with spaced terminal ends, wherein lines of magnetic flux pass through said air gap between said terminal ends, a sensing element which is sensitive to a magnetic field mounted between said rim in said air gap, the terminal ends of said armature member being pyramidically-shaped and having flat terminus portions which have a surface area substantially equal to the surface area of said sensing element for concentrating the lines of magnetic flux through said sensing element, and a movable variable cross section rod-shaped core members insertable into said central annular bore of said tubular support member and movable in relation to said armature member for varying the magnetic flux in accordance with the distance said movable rod-shaped core member is moved relative to said stationary annular magnetic armature member.

2. The analog distance sensor, according to claim 1, when said sensing element which is sensitive to the magnetic field is a Hall effect sensor.

3. The analog distance sensor, according to claim 1, wherein a permanent magnet is said stationary annular armature member.

4. The analog distance sensor, according to claim 1, wherein said stationary annular armature member includes a permanent magnet.

5. The analog distance sensor, according to claim 1, wherein said movable rod-shaped core member has a conical shape.

6. The analog distance sensor, according to claim 1, wherein said movable rod-shaped core member includes a flat surface.

7. The analog distance sensor, according to claim 1, wherein said movable rod-shaped core member includes a wedge-shaped recess.

8. The analog distance sensor, according to claim 6, wherein said movable rod-shaped core member is moved axially in relation to said stationary annular magnetic armature member for short-circuiting the lines of flux through said movable rod-shaped core member.

9. The analog distance sensor, according to claim 7, wherein said movable rod-shaped core member is moved angularly in relation to said stationary annular magnetic armature member for short-circuiting the lines of flux through said movable rod-shaped core member.

10. The analog distance sensor, according to claim 1, wherein said movable rod-shaped core member is concentrically disposed within said annular bore of said tubular support member.