PROCESS FOR MEASURING PRELOADING OF LOW-ROLLING RESISTANCE BEARINGS

• US 20110219886A1
• Filed: 03/12/2010
• Published: 09/15/2011
• Est. Priority Date: 03/12/2010
• Status: Active Grant

• Current Assignee: Jeffrey S. Wickens
• Original Assignee: Jeffrey S. Wickens
• Inventors: Wickens, Jeffrey S.
• Granted Patent: US 8,342,039 B2
• Time in Patent Office: Days
• US Class Current: 73/862.55
• CPC Class Codes: F16C 19/182 in tandem arrangement
• CPC Class Codes: F16C 19/548 in O-arrangement
• CPC Class Codes: F16C 2229/00 Setting preload
• CPC Class Codes: F16C 2361/61 Toothed gear systems, e.g. support of pinion shafts
• CPC Class Codes: F16C 25/06 Ball or roller bearings

Abstract

A system and method for measuring the preload condition of a vehicle differential gear assembly includes a multi-axis load cell having a spherical load button. The differential assembly is supported by the pinion shaft and the load cell button is positioned within a carrier housing hole. The pinion shaft is then rotated relative to the housing resulting in the housing to rotate along with the pinion shaft and abut against the load button. The resulting force against the button is measured in three orthogonal directions permitting an accurate force vector to be determined. The bearings preload is simultaneously set by applying an axial compressive force against the bearings while the pinion shaft is rotated.

Claims

1. A method of measuring bearing preload in a differential gear assembly'"'"'s angular contact ball bearing set, the bearing set supporting a pinion shaft within a housing having at least one cylindrical opening formed in an exterior surface of the housing, said method comprising the steps of:

providing a multi-axis load cell having a spherical load button;

positioning said spherical load button within one of said cylindrical openings;

rotating said pinion shaft relative to said housing so that said rotating pinion shaft imparts a torque to said housing through said bearing set, wherein said housing rotates and an inner surface of said cylindrical opening abuts said load button; and

measuring a force applied by said housing against said load button.

2. A method as defined in claim 1, further comprising the step of supporting said differential gear assembly from said pinion shaft, wherein said housing is fully supported by said bearing set.

3. A method as defined in claim 2, wherein said step of measuring a force further comprises measuring three orthogonal forces applied to said load button by said housing.

4. A method as defined in claim 2, further comprising the step of advancing a nut axially along a threaded portion of said pinion shaft to apply a compressive force upon said bearing set thereby changing the rolling resistance within said bearing set and changing the force applied by said housing against said load button.

5. A method as defined in claim 1, wherein said step of positioning said spherical load button further comprises:

extending said load cell toward said housing wherein said load button is linearly coextensive with a centerline of one of said cylindrical openings; and

moving at least one of said load cell and housing relative to each other axially along said centerline such that at least a portion of said load button is disposed within said one of said cylindrical openings.

6. A method as defined in claim 5, wherein said centerline is substantially vertical and said step of moving at least one of said load cell and housing relative to each other further comprises translating said housing vertically downwardly.

7. A method of measuring bearing preload in a differential gear assembly having an input shaft supported by an antifriction bearing set within a differential, said method comprising the steps of:

lifting and supporting said differential gear assembly by said input shaft such that a longitudinal axis of said input shaft is in a known orientation;

positioning a spherical load button within a cylindrical opening in the housing;

rotating said input shaft relative to said housing so that said rotating input shaft imparts a torque to said housing through said bearing set, wherein said housing rotates to abut an inner surface of said cylindrical opening against said load button; and

measuring a force applied by said housing against said load button in three orthogonal directions.

8. A method as defined in claim 7, further comprising the step of applying a compressive force to said bearing set axially while said input shaft is rotated.

9. A method as defined in claim 7, further comprising the steps of:

extending said load button toward said housing wherein said load button is coextensive with a centerline of said cylindrical opening; and

moving at least one of said load button and housing relative to each other along said centerline such that at least a portion of said load button is disposed within said cylindrical opening.

10. A method as defined in claim 9, wherein said step of measuring a force further comprises:

providing a piezoresistive triaxial load cell and mounting said spherical ball upon a force input plate of said load cell.

11. A method as defined in claim 7, wherein said known orientation is vertical.

12. A system for measuring bearing preload in a differential gear assembly'"'"'s angular contact ball bearing set, the bearing set supporting a pinion shaft within a housing having at least one cylindrical opening formed in an exterior surface of the housing, comprising:

an actuator arm that is movable from a collapsed rest position to an extended position;

a multi-axis load cell mounted upon and end of said actuator arm;

a load button mounted to a force input plate said load cell, said load button being sized to fit within said at least one cylindrical opening; and

means for lifting and rotating said differential gear assembly by said pinion shaft;

wherein said load button is coextensive with one of said cylindrical openings when said actuator arm is in said extended position and said load cell measures a resultant force transmitted through said bearing set when said lifting and rotating means rotates said pinion shaft.

13. A system as defined in claim 12, wherein said multi-axis load cell is a triaxial piezoresistive load cell.

14. A system as defined in claim 12, wherein said load button comprises a spherical contact head, wherein said spherical contact head is sized to be received within said at least one cylindrical opening.

15. A system as defined in claim 14, further comprising:

means for tightening a pinion nut along said pinion shaft to compress and preload said bearing set; and

a controller which is communicatively coupled to;

said load cell, said lifting and driving means, and said pinion nut driving means, wherein said controller stops said pinion nut tightening means when said load cell measures a desired resultant force.