Serviceable wheel speed sensor with magnet assisted retention

• US 5,296,805 A
• Filed: 08/17/1992
• Issued: 03/22/1994
• Est. Priority Date: 08/17/1992
• Status: Expired due to Term

• Current Assignee: SKF USA Incorporated (SKF)
• Original Assignee: General Motors Corporation (Motors Liquidation Co. GUC Trust)
• Inventors: Dubovec, Jan, Clark, Edward R.
• Primary Examiner(s): Strecker, Gerard R.
• Application Number:
  US07/930,946
• Time in Patent Office: 582 Days
• Field of Search: 324/173, 324/174, 324/207.15, 324/207.25, 310/68 B, 310/168, 188/181 R, 384/446, 384/448
• US Class Current: 324/174
• CPC Class Codes: B60T 8/171 Detecting parameters used in the regulation; Measuring values used in the regulation
• CPC Class Codes: F16C 19/187 with all four raceways integrated on parts other than race rings, e.g. fourth generation hubs
• CPC Class Codes: F16C 2326/02 Wheel hubs or castors in general B60B
• CPC Class Codes: F16C 33/723 Shaft end sealing means, e.g. cup-shaped caps or covers
• CPC Class Codes: F16C 41/007 Encoders, e.g. parts with a plurality of alternating magnetic poles
• CPC Class Codes: G01P 3/443 mounted in bearings bearings F16C

Abstract

A serviceable ABS wheel speed sensor uses the permanent magnet both to provide an efficient magnetic circuit and to provide part of the retention force that retains a stator subassembly and a sensor subassembly together. The stator subassembly is a plastic end cap that seals one end of the wheel bearing, and has an annular steel web molded into it. A permanent magnet is located behind the web. The sensor subassembly is a plastic plug that fits into the end cap, and has a sensor coil with a steel plate in front abuttable with the stator subassembly web. When the two are assembled, the web and plate are pulled and retained together by the magnet. The coil and magnet are also thereby located proximate to spinning exciter teeth on one of the bearing races to provide an efficient magnetic circuit and strong signal.

Claims

1. For use in a vehicle wheel bearing having a stationary bearing race and a coaxial rotating race forming an annular space therebetween, in which said rotating race has an exciter ring secured thereto including a cylindrical array of magnetic material teeth, an improved serviceable seal and speed sensor assembly, comprising,

a stator subassembly including a seal portion fixed to said stationary bearing race and covering said annular space, said stator subassembly further including a magnetic clamping portion proximate said teeth,

a sensor subassembly including a speed sensor and a speed sensor support adapted to interfit axially with said stator subassembly so as to locate said speed sensor proximate said exciter ring teeth, and also having a magnetic clamping portion abuttable with said stator subassembly clamping portion, and,

a permanent magnet secured to one of said stator and sensor subassemblies in abutment with said abutted magnetic clamping portions,

whereby said magnet is proximate to both said speed sensor and exciter ring teeth, so as to provide magnetic flux therefor, and also serves to magnetically retain said stator and sensor subassembly clamping portions together and thereby retain said subassemblies together.

2. For use in a vehicle wheel bearing having a stationary bearing race and a coaxial rotating race forming an annular space therebetween, in which said rotating race has an exciter ring secured thereto including an axially extending cylindrical array of magnetic material teeth, an improved serviceable seal and speed sensor assembly, comprising,

a stator subassembly including a seal portion fixed to said stationary bearing race and covering said annular space, said stator subassembly further including a magnetic clamping portion proximate said teeth and a permanent magnet secured thereto in axial abutment with said stator magnetic clamping portion, and,

a sensor subassembly including a speed sensor and a speed sensor support adapted to interfit axially with said stator subassembly so as to locate said speed sensor proximate said exciter ring teeth, and also having a magnetic clamping portion axially abuttable with said stator subassembly clamping portion,

whereby said sensor assembly is pulled axially toward said stator assembly by said magnet as said clamping portions move into abutment, which magnet is thereby located proximate to both said speed sensor and exciter ring teeth so as to efficiently provide magnetic flux therefor.

3. For use in a vehicle wheel bearing having a stationary bearing race and a coaxial rotating race forming an annular space therebetween, in which said rotating race has an exciter ring secured thereto including an axially extending cylindrical array of magnetic material teeth, an improved serviceable seal and speed sensor assembly, comprising,

a stator subassembly including an end cap fixed to said stationary bearing race and covering said annular space, said end cap further including an annular magnetic material web integral thereto and proximate said teeth with a permanent magnet secured thereto behind said web, and,

a sensor subassembly including a speed sensor coil and a coil support adapted to interfit axially with said stator subassembly so as to locate said speed sensor coil proximate said exciter ring teeth, and also having a magnetic plate axially abuttable with said stator subassembly web,

whereby, as said sensor subassembly is interfitted with said stator subassembly said web and plate are pulled together by said magnet, which magnet is thereby located proximate to both said speed sensor coil and exciter ring teeth so as to efficiently provide magnetic flux therefor.