SENSOR-EQUIPPED BEARING FOR WHEEL

• US 20100046871A1
• Filed: 03/25/2008
• Published: 02/25/2010
• Est. Priority Date: 03/27/2007
• Status: Active Grant

• Current Assignee: NTN Corporation
• Original Assignee: NTN Corporation
• Inventors: Baba, Kazuhiro, Nishikawa, Kentarou, Komori, Kazuo, Takahashi, Toru, Norimatsu, Takayuki
• Granted Patent: US 8,123,411 B2
• Time in Patent Office: Days
• US Class Current: 384/448
• CPC Class Codes: B60B 27/0005 with ball bearings
• CPC Class Codes: B60B 27/0068 the element being a sensor
• CPC Class Codes: B60B 27/0094 one or more of the bearing races are formed by the hub
• CPC Class Codes: F16C 19/186 with three raceways provided integrally on parts other than race rings, e.g. third generation hubs
• CPC Class Codes: F16C 19/522 related to load on the bearing, e.g. bearings with load sensors or means to protect the bearing against overload
• CPC Class Codes: F16C 2326/02 Wheel hubs or castors in general B60B
• CPC Class Codes: F16C 33/58 Raceways; Race rings
• CPC Class Codes: F16C 41/00 Other accessories, e.g. devices integrated in the bearing not relating to the bearing function as such
• CPC Class Codes: G01L 5/0019 by using strain gages, piezoelectric, piezo-resistive or other ohmic-resistance based sensors

Abstract

To provide a sensor equipped wheel support bearing assembly, in which a load sensor can be installed compactly in an automotive vehicle, maintaining a high sensitivity while damage and/or malfunction caused by the external environments and/or the electromagnetic noises are avoided, with low manufacturing cost. This bearing assembly includes outer and inner members having respective rolling surfaces and a plurality of rows of rolling elements interposed between those rolling surfaces. A strain sensor unit including a sensor element is fitted to one of the outer and inner members, which is a stationary member, for example, the outer member. A sensor mounting surface of the strain sensor unit fitted with the sensor element has a covering member made of a resin, which is over-molded, or an elastomer bonded by vulcanization, so as to cover the sensor element sealingly.

Claims

1. A sensor equipped wheel support bearing assembly for supporting a vehicle wheel rotatably relative to a vehicle body, which assembly comprises:

an outer member having an inner periphery formed with a plurality of rolling surfaces;

an inner member having rolling surfaces defined therein in face-to-face relation with the respective rolling surfaces in the outer member;

a plurality of rows of rolling elements interposed between those rolling surfaces;

a strain sensor unit, made up of a strain generating member and a sensor element fitted to the strain generating member for detecting strains induced in the strain generating member, is fitted to one of the outer and inner members, that serves as a stationary member; and

a covering member that covers at least the sensor element sealingly, provided on a mounting surface of the strain generating member of the strain sensor unit, on which the sensor element is mounted, the covering member being made of a resin, which is over-molded, or an elastomer bonded by vulcanization.

2. The sensor equipped wheel support bearing assembly as claimed in claim 1, wherein the strain generating member includes first and second contact fixing elements fixed to respective locations of the stationary member, the first contact fixing element being fixed to a flange surface provided in the stationary member and the second contact fixing element being fixed to a peripheral surface of the stationary member.

3. The sensor equipped wheel support bearing assembly as claimed in claim 1, wherein the sensor element in the strain sensor unit is provided with a cable drawn outwardly from a location proximate to the second contact fixing element in the strain generating member fixed to the peripheral surface of the stationary member in a direction circumferentially of the stationary member.

4. The sensor equipped wheel support bearing assembly as claimed in claim 3, wherein the cable is fixed to the peripheral surface of the stationary member by means of a clamp member equipped with a ferrite.

5. The sensor equipped wheel support bearing assembly as claimed in claim 1, further comprising an acting force calculating section operable in response to an output from the sensor element to calculate an external force acting on the wheel support bearing assembly or a force acting between a tire and a road surface.

6. The sensor equipped wheel support bearing assembly as claimed in claim 1, wherein the strain generating member is of an L-shaped configuration including a radially oriented segment, extending in a radial direction, and an axially oriented segment extending in an axial direction.

7. The sensor equipped wheel support bearing assembly as claimed in claim 1, wherein the strain generating member of the strain sensor unit includes two or more fixing faces adapted to be fixed to respective locations of the outer member spaced from each other, and contact fixing elements each interposed between each of the fixing faces and a fixing target surface to which the strain sensor unit is to be fixed, the contact fixing element being in the form of a spacer member having opposite end faces, one end face oriented towards the fixing face having a shape conforming with that of the fixing face and the other end face oriented towards the fixing target surface having a shape conforming with that of the fixing target surface.

8. The sensor equipped wheel support bearing assembly as claimed in claim 7, wherein at least one of the two or more spacer members is so designed that the end face oriented towards the fixing face is in the form of a flat face and the end face oriented towards the fixing target surface is in the form of a cylindrical surface.

9. The sensor equipped wheel support bearing assembly as claimed in claim 1, wherein one of the outer and inner members, that serves as the stationary member, is formed integrally with a sensor fixing boss, and the strain generating member and at least one strain sensor unit fitted to the strain generating member are provided in the stationary member through the sensor fixing boss.

10. The sensor equipped wheel support bearing assembly as claimed in claim 9, wherein the sensor fixing boss includes a first boss formed integrally with the flange surface provided in the stationary member and a second boss formed integrally with the peripheral surface of the stationary member, and wherein the strain generating member includes a first contact fixing element adapted to be fixed to a foremost end face of the first boss in contact therewith and a second contact fixing element adapted to be fixed to a foremost end face of the second boss in contact therewith.