Claims
- 1. A position sensor for detecting a displacement of an object, comprising:
- a movable member coupled to said object;
- permanent magnet means connected to said movable member for producing a magnetic field which varies in a predetermined region in dependence on the displacement of said movable member;
- core means made of a magnetically soft material and disposed in said predetermined region for forming a magnetic circuit with said magnet means;
- electric coil means including at least one coil wound around said core means for detecting a change in magnetic flux in said magnetically soft member; and
- means for detecting the displacement of said object, comprising,
- means for applying a pulse voltage to a first terminal of said coil to saturate magnetically said core means, and
- means coupled to a second terminal of said coil for producing a displacement output signal indicative of the displacement of said magnet means and therefore of said movable body based on the time between application of said pulse voltage and saturation of said core means.
- 2. A position sensor according to claim 1, wherein said core means consists of:
- an amorphous magnetic material.
- 3. A position sensor according to claim 2, further comprising:
- a synthetic resin board to which said core means is secured.
- 4. A position sensor according to claim 3, further comprising:
- a connecting member secured to one end of said movable member and acting to displace said permanent magnet means.
- 5. A position sensor according to claim 4, further comprising:
- a spring for applying a biasing force to said permanent magnet means at its other end.
- 6. A position sensor according to claim 1, further comprising:
- said permanent magnet means magnetized in a longitudinal direction thereof and fixed to said movable member;
- said core means comprising opposed core members each of which comprises a magnetically soft material positioned on opposite sides of said magnet means;
- said movable member undergoing displacement in a direction perpendicular to the longitudinal axis of the permanent magnet means.
- 7. A position sensor according to claim 1, further comprising:
- said core means having a longitudinal direction; and
- said movable member means movable in the longitudinal direction of said core means.
- 8. A position sensor according to claim 1, further comprising:
- said core means having a longitudinal axis; and
- said movable member means movable in a direction perpendicular to the longitudinal axis of said core means.
- 9. A position sensor device according to claim 1, wherein said detecting means comprises:
- constant current means for producing a constant current through said coil upon application of said pulse voltage to said first terminal of said coil.
- 10. A rotational angle sensor according to claim 9, wherein said constant current means comprises:
- at least one field effect transistor connected to said second terminal of said coil.
Parent Case Info
This is a continuation of application Ser. No. 182,662, filed Aug. 29, 1980, now abandoned.
US Referenced Citations (2)
Number |
Name |
Date |
Kind |
3958203 |
Bernin |
May 1976 |
|
4140971 |
Blincoe |
Feb 1979 |
|
Foreign Referenced Citations (1)
Number |
Date |
Country |
909023 |
Oct 1962 |
GBX |
Continuations (1)
|
Number |
Date |
Country |
Parent |
182662 |
Aug 1980 |
|