Electromagnetic locking differential assembly

• US 7,137,921 B2
• Filed: 08/19/2005
• Issued: 11/21/2006
• Est. Priority Date: 09/29/2003
• Status: Active Grant

• Current Assignee: American AXLE & Manufacturing Incorporated (American AXLE & Manufacturing Holdings Incorporated)
• Original Assignee: American AXLE & Manufacturing Incorporated (American AXLE & Manufacturing Holdings Incorporated)
• Inventors: DeGowske, Robert J.
• Primary Examiner(s): HO, HA DINH
• Application Number:
  US11/208,345
• Publication Number:
  US 20050277508A1
• Time in Patent Office: 459 Days
• Field of Search: 475/231, 475/240, 475/249, 192/84.31, 192/84.95, 192/84.951, 188/31, 188/161, 188/163, 188/171
• US Class Current: 475/231
• CPC Class Codes: F16H 2048/106 characterised by two sun gears
• CPC Class Codes: F16H 2048/204 Control of arrangements for suppressing differential actions
• CPC Class Codes: F16H 2048/346 using a linear motor
• CPC Class Codes: F16H 48/08 comprising bevel gears
• CPC Class Codes: F16H 48/10 with orbital spur gears
• CPC Class Codes: F16H 48/11 having intermeshing planet gears
• CPC Class Codes: F16H 48/24 using positive clutches or brakes
• CPC Class Codes: F16H 48/30 using externally-actuatable means
• CPC Class Codes: F16H 48/34 using electromagnetic or electric actuators
• CPC Class Codes: F16H 48/40 characterised by features of the rotating cases

Abstract

A method of transitioning between modes of differentiation in a differential includes measuring a vehicle parameter, determining a mode of differentiation, selectively providing an electrical signal to an electromagnet based on the determination, generating a magnetic field, moving the electromagnet and selectively operating the differential in one of an open mode of differentiation and a locked mode of differentiation in response to movement of the electromagnet.

Claims

1. A method of transitioning between modes of differentiation in a differential having a case and a side gear, the differential drivingly interconnecting a first rotatable shaft and a second rotatable shaft, the method comprising:

measuring a vehicle parameter;

determining a mode of differentiation;

selectively providing an electrical signal to an electromagnet based on said determination;

generating a magnetic field;

moving said electromagnet; and

selectively drivingly interconnecting the side gear and the case in response to movement of said electromagnet.

2. The method of claim 1 wherein the modes of differentiation include open and locked.

3. The method of claim 2 wherein the step of measuring a vehicle parameter includes calculating a differential speed between the first rotatable shaft and the second rotatable shaft.

4. The method of claim 3 wherein the step of measuring a vehicle parameter includes receiving a signal indicating that a brake of a vehicle is being applied.

5. The method of claim 1 wherein said vehicle parameter is selected from the group consisting of a wheel speed, a vehicle speed, a gear position, a transfer case range position, application of one or more vehicle brakes and a differential speed between the first and second shafts.

6. The method of claim 1 further including selectively engaging a ring with the side gear, said ring being fixed to said electromagnet and slidably positioned within a pocket of the case.

7. The method of claim 6 wherein said ring includes a plurality of axially extending dogs selectively engageable with a plurality of dogs extending from the side gear.

8. A method of transitioning between modes of differentiation in a differential, the method comprising:

measuring a vehicle parameter;

determining a mode of differentiation;

selectively providing an electrical signal to an electromagnet based on said determination;

generating a magnetic field;

moving said electromagnet; and

selectively operating the differential in one of an open mode of differentiation and a locked mode of differentiation in response to movement of said electromagnet.

9. The method of claim 8 wherein said differential includes a case, a pair of pinion gears and a pair of side gears, the gears being in meshing engagement with one another, wherein the method further includes drivingly coupling said case with one of said side gears to operate the differential in the locked mode.

10. The method of claim 9 further including coupling an actuator ring to the electromagnet and selectively drivingly engaging said actuator ring with one of said side gears.

11. The method of claim 10 further including rotating said pair of pinion gears about a first common axis and rotating said side gears about a second common axis, said first axis being substantially perpendicular to said second axis.

12. The method of claim 11 further including biasing said electromagnet toward a position where said differential operates in said open mode of differentiation.

13. The method of claim 9 further including rotating said pinion gears about axes parallel to and offset from one another.

14. The method of claim 8 wherein said differential includes a rotatable case and wherein said step of moving said electromagnet includes axially translating said electromagnet relative to said rotatable case.

15. The method of claim 14 further including positioning a non-ferromagnetic spacer between said electromagnet and said rotatable case to assure said electromagnet moves in a direction to switch said mode of differentiation from open to locked when said electromagnet is energized.

16. The method of claim 8 further including placing a controller in communication with a sensor operable to provide a signal indicative of said vehicle parameter wherein said controller determines said mode of differentiation.

17. A method of operating a differential having a moveable electromagnet, the method comprising:

selectively providing an electrical signal to the moveable electromagnet;

generating a magnetic field;

moving the electromagnet; and

selectively operating the differential in one of an open mode of differentiation and a locked mode of differentiation in response to movement of the electromagnet.

18. The method of claim 17 further including biasing said electromagnet toward a position where said differential operates in said open mode of differentiation.

19. The method of claim 18 further including determining when the differential should be operated in the locked mode of differentiation.

20. The method of claim 19 further including drivingly coupling a first rotatable shaft and a second rotatable shaft to the differential, the first and second rotatable shafts being aligned on a common axis.