US4829245A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Variable reluctance electromagnetic sensor with pole piece-magnet assembly locking mechanism and method of assembly
Assignee: Bendix Electronics SA
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Filing: 1987-12-08
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Granted: 1989-05-09
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Expires: 2007-12-08
Abstract
Abstract The invention is in the field of electromagnetic transducers. The sensor according to the invention includes an electrical winding 2 mounted on a carcass 1 hollowed with a cavity 7 which receives a metal pole piece 5 and a permanent magnet 6. According to the invention inclined ribs 20 are formed in the cavity 7 in order to constitute a means of progressively locking the magnet by the wedge effect during the insertion of this magnet and of the pole piece into the cavity. It is thus possible to accurately adjust the distance d which separates the end 21 of the pole piece from a reference surface 22 of the carcass 1. Application to the production of a shaft speed sensor or a wheel speed sensor for a motor vehicle.
Inventors
- 👤 Gilbert Echasseriau
- 👤 Patrice Oliveau
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 11:55
CPC Classifications
G; G01; G01P; G01P3/00; G01P3/42; G01P3/44; G01P3/48; G01P3/481; G01P3/488; G01P1/00; G01P1/02; G01P1/026; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/4902; Y10T29/49075
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
130 words
A variable reluctance electromagnetic sensor comprising: tubular casing having a cavity; reference surface mark means on the outside of said tubular casing near one end thereof; an electrical coil wound around said casing, one end of said coil coincident with said reference surface mark means; an assembly comprising a permanent magnet and a pole piece inserted end to end in said cavity; said end of said pole piece opposite said permanent magnet being the free end, said free end being positioned a predetermined distance form said reference surface mark means; and locking means for wedging said assembly in said cavity, said locking means having a truncated conical surface progressively reducing the diameter of said cavity from a point intermediate the ends of said cavity towards an end of said cavity.
Claim 2
Dependent Claim
130 words
A variable reluctance electromagnetic sensor comprising: tubular casing having a cavity; reference surface mark means on the outside of said tubular casing near one end thereof; an electrical coil wound around said casing, one end of said coil coincident with said reference surface mark means; an assembly comprising a permanent magnet and a pole piece inserted end to end in said cavity; said end of said pole piece opposite said permanent magnet being the free end, said free end being positioned a predetermined distance form said reference surface mark means; and locking means for wedging said assembly in said cavity, said locking means having a truncated conical surface progressively reducing the diameter of said cavity from a point intermediate the ends of said cavity towards an end of said cavity.
Claim 3
Dependent Claim
75 words
A sensor according to claim 1, wherein said locking means comprises a group of ribs integral to and spaced around the wall of said cavity, the foot of each of said ribs being parallel to the axis of said cavity and the edge for each of said ribs inclined to said axis for progressively reducing the diameter of said cavity from a point intermediate the ends of said cavity towards an end of said cavity.
Claim 4
Dependent Claim
20 words
A sensor according to claim 2, characterized in that said ribs are regularly distributed over the wall of said cavity.
Claim 5
Dependent Claim
18 words
A sensor according to claim 1, characterized in that said locking means immobilizes one end of said magnet.
Claim 6
Dependent Claim
24 words
A sensor according to claim 1, wherein said pole piece has a peripheral knurling so that it is retained in said cavity by friction.
Claim 7
Dependent Claim
17 words
A sensor according to claim 1 wherein said locking means immobilizes one end of said pole piece.
Claim 8
Dependent Claim
20 words
A sensor according to claim 1, additionally including a resin securing the end of said magnet opposite said pole piece.
Claim 9
Independent Claim
128 words
A method of assemblying a variable reluctance electromagnetic sensor comprising the steps of: securing a tubular casing having a cavity; providing locking means in one end of said tubular casing; marking a reference mark on said casing a predetermined distance from an end of said cavity; winding an electrical coil around the casing with one end of said coil coincident with said reference mark; inserting end-to-end into said cavity an assembly comprising a permanent magnet and a pole piece until said assembly is wedged in said cavity by said locking means; monitoring the distance form the free end of the pole piece from a reference surface marked on the casing; and then removing the wedging insertion pressure from the assembly when said distance equals a predetermined value d.
Claim 10
Independent Claim
128 words
A method of assemblying a variable reluctance electromagnetic sensor comprising the steps of: securing a tubular casing having a cavity; providing locking means in one end of said tubular casing; marking a reference mark on said casing a predetermined distance from an end of said cavity; winding an electrical coil around the casing with one end of said coil coincident with said reference mark; inserting end-to-end into said cavity an assembly comprising a permanent magnet and a pole piece until said assembly is wedged in said cavity by said locking means; monitoring the distance form the free end of the pole piece from a reference surface marked on the casing; and then removing the wedging insertion pressure from the assembly when said distance equals a predetermined value d.
Claim 11
Dependent Claim
23 words
A method according to claim 8, characterized in that, on removing the pressure, said locking means is in a state of elastic distortion.
Claim 12
Dependent Claim
23 words
A method according to claim 8, characterized in that, on removing the pressure, said locking means is in a state of plastic distortion.
Claim 13
Dependent Claim
27 words
A method according to claim 8, additionally including the step of injecting resin into said cavity for securing the locking of the magnet and the pole piece.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-05-08 | 1992-11-07 | 1993-05-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-05-08 | 1996-11-07 | 1997-05-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-05-08 | 2000-11-07 | 2001-05-09 | $7700.00 | Window Closed / Lapsed |