# Patent

## Title
Power transfer assembly with gasket having magnet

## Abstract

An axle assembly for a vehicle includes a housing, a differential assembly rotatably supported within the housing, a differential cover and a gasket assembly positioned between the housing and the differential cover. The gasket assembly includes a body and a magnet coupled to the body. The magnet is positioned in communication with a lubricant located within the interior of the housing.

## Background
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation of U.S. patent application Ser. No. 10/992,207 filed on Nov. 18, 2004. The disclosure of the above application is incorporated herein by reference.


BACKGROUND OF THE INVENTION
The present invention relates to a gasket assembly for a power transfer assembly used in a vehicle drivetrain, and more particularly, to a gasket having an integral magnet.
Many vehicles are equipped with a housing rotatably supporting a differential assembly. The differential assembly is typically positioned between a vehicle transmission and a pair of output shafts to supply a driving force to the vehicle wheels. The differential assembly includes gearing to transmit drive torque from a differential housing to the output shafts while permitting speed differentiation therebetween. A ring gear is typically coupled to the differential housing. The ring gear is in driven engagement with a pinion gear coupled to a rotatable input member. A volume of lubricating fluid is stored within the housing to lubricate the gearing. Over time, the gears, bearings and housing may wear such that metal particles enter the lubricant. A differential cover is typically coupled to the housing to protect the gearing from the external environment and to maintain the lubricant within the housing. The differential cover is removable to allow service access to the gearing.
It is known to permanently couple a magnet to the differential cover or the housing to function as a metallic particle collection device. Attachment of the magnet to the bottom of the housing or to the differential cover is typically costly due to the requisite cleaning and preparation processes associated with adhesively attaching a magnet. Furthermore, durability concerns exist because the magnets may dislodge or move within the housing leading to possible component damage.
SUMMARY OF THE INVENTION
The present invention generally relates to an axle assembly for a vehicle. The axle assembly includes a housing, a differential assembly rotatably supported within the housing, a differential cover and a gasket assembly positioned between the housing and the differential cover. The gasket assembly includes a body and a magnet coupled to the body. The magnet is positioned in communication with a lubricant located within the interior of the housing.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.



BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:
FIG. 1 is an exploded perspective view of an exemplary axle assembly constructed in accordance with the teachings of the present invention;
FIG. 2 is a partial fragmentary exploded perspective view depicting a carrier housing, a differential cover, and a cover gasket and magnet assembly of the present invention;
FIG. 3 is an enlarged fragmentary perspective view of the cover gasket and magnet assembly of the present invention;
FIG. 4 is a partial end view of an axle assembly having the differential cover removed; and
FIG. 5 is a fragmentary sectional side view of an exemplary axle assembly including a cover gasket and magnet assembly.



DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.
FIGS. 1 and 2 depict an exemplary power transfer assembly, such as a drive axle assembly 12, adapted for use in a motor vehicle. Drive axle assembly 12 includes an axle carrier 14 for rotatably mounting an input gearset including a pinion gear 16 and a ring gear 18. A differential assembly 20 is drivingly interconnected to ring gear 18. Differential assembly 20 functions to transfer power from the input gearset to a pair of axle shafts (not shown) while compensating for any difference in axle shaft rotational speed as may occur during a turn or other steering maneuver. Differential assembly 20 includes a pair of pinion gears 24 and a pair of side gears 26 mounted in a differential housing 27. Side gears 26 are drivingly interconnected to the axle shafts thereby providing a power transmission path to a pair of vehicle wheels (not shown). To facilitate proper function of axle assembly 12, differential housing 27 is rotatably mounted on a pair of differential bearings 28. Specifically, axle carrier 14 includes two semi-circular journals (not shown) for supporting approximately one-half of each differential bearings 28. Similarly, a pair of bearing caps 30 journally support the remaining approximate one-half of each differential bearings 28 when coupled to axle carrier 14 via threaded fasteners 31. It should be appreciated that axle carrier 14 further includes an opening 32 to provide access to the differential assembly 20.
Differential cover pan 10 is useful for providing service access to the components mounted within the axle carrier 14. Cover pan 10 is preferably stamped from a steel sheet and formed in the shape of a shell 42 having an inner surface 44 and an outer surface 46 terminating at a mounting flange 48. Mounting flange 48 includes a plurality of fastener apertures 50 extending therethrough for securing cover pan 10 to axle carrier 14 and enclosing opening 32.
FIGS. 2 through 5 depict a cover gasket and magnet assembly 52 that is sealingly positioned between differential cover pan 10 and axle carrier 14. Cover gasket and magnet assembly 52 is shaped as a closed ring having the shape of mounting flange 48 on differential cover pan 10. A plurality of apertures 54 are circumferentially spaced apart from one another and positioned to align with the plurality of fastener apertures 50 extending through cover pan 10. A plurality of fasteners 56 extends through fastener apertures 50 of cover pan 10 and apertures 54 of cover gasket and magnet assembly 52. Fasteners 56 are threadingly engaged with threaded apertures 57 formed within axle carrier 14. Fasteners 56 provide a clamping force to biasedly deform at least a portion of cover gasket and magnet assembly 52 to enclose the opening 32 formed in axle carrier 14.
In the embodiment depicted in the Figures, cover gasket and magnet assembly 52 includes a rigid body 58, a magnet 60, an elastomer 62 and a plurality of rivets 64. Rigid body 58 is shaped as a ring having a substantially planar first surface 66 and a substantially planar second surface 68. A plurality of fastener apertures 70 extend through rigid body 58. A window 72 and magnet fastener apertures 74 also extend through rigid body 58. Window 72 functions to expose additional surface area of magnet 60 to potentially contaminated lubricant. In this manner, the surface area of magnet 60 exposed to lubricant is maximized. Rigid body 58 may be constructed from metal, or a rigid composite.
Elastomer 62 is coupled to rigid body 58 using any number of methods such as molding, coating, gluing or any other method suitable for attaching the elastomer to the rigid body. Elastomer 62 includes a first portion 76 coupled to first surface 66 of rigid body 58. First portion 76 includes a first sealing bead 78 and a second sealing bead 80 extending about the periphery of rigid body 58. A plurality of sealing rings 82 are circumferentially spaced apart from one another and positioned on first surface 66 of body 58. Each sealing ring 82 circumscribes a fastener aperture 70 and interrupts sealing beads 78 and 80. It should be appreciated that elastomer 62 may include any number of shapes where first sealing bead 78, second sealing bead 80 and sealing ring 82 may be integrally formed with one another, separate from another or may be shaped to include differential profiles from those depicted in the drawings.
Elastomer 62 includes a second portion 84 coupled to second surface 68 of rigid body 58. In the embodiment shown, second portion 84 is shaped substantially similar to first portion 76. However, one skilled in the art will appreciate that the first and second portions need not be identical to function according to the principles of the present invention. During installation of fasteners 56, a clamping force is provided between mounting flange 48 and axle carrier 14 such that first portion 76 and second portion 84 of elastomer 62 are at least partially deformed. Specifically, first bead 78 and second bead 80 are positioned in biased engagement with a mounting face 86 of axle carrier 14. Similarly, second portion 84 of elastomer 62 is biasedly engaged with mounting flange 48.
Magnet 60 is a substantially plate-shaped member having a first substantially planar surface 88 and a second substantially planar opposite surface 90. A plurality of apertures 91 extend through magnet 60. Rivets 64 include a head portion 92 and hollow cylindrical body portion 94. Each cylindrical body portion 94 extends through an aperture 74 of rigid body 58 and an aperture 91 of magnet 60. Tubular portions 94 are deformed to form a flange 96 capturing magnet 60 and rigid body 58 between head portion 92 and flange 96. Magnet 60 is sized to radially inwardly extend beyond a surface 98 of rigid body 58. As such, the surface area of magnet 60 exposed to lubricant is maximized. Based on this construction, a magnet of relatively small size may be utilized to attract metallic particles within the lubricant.
FIG. 4 depicts cover gasket and magnet assembly 52 properly positioned on axle carrier 14. A volume of lubricant within axle carrier 14 is indicated at reference numeral 100. Magnet 60 is positioned below the surface of lubricant 100 at or near the lowest point of axle carrier 14 in an attempt to attract the greatest number of magnetic particles contained within the lubricant. Through the use of cover gasket and magnet assembly 52. The magnet 60 may be properly positioned at or near a low velocity zone of lubricant to ensure particle retention to the magnet surfaces. To assure proper positioning of cover gasket and magnet assembly 52 relative to axle carrier 14, body 58 includes a radially inwardly extending tab 102. Tab 102 may be labeled “TOP” or have some other method of notifying an installer that tab 102 is to be positioned at the uppermost threaded aperture 57.
Additional benefits of cover gasket and magnet assembly 52 may be realized. For example, a failure mode of an operator forgetting to glue a magnet within axle carrier 14 may be avoided because visual verification of the presence of cover gasket and magnet assembly 52 may be made. Furthermore, if cover gasket and magnet assembly 52 were not in place, the assembly would most likely leak lubricant immediately or soon after fill. In addition, because magnet 60 is a component of cover gasket and magnet assembly 52, a higher probability exists that the magnet will be cleaned if the differential cover is removed by a service technician. Typically, many service technicians will clean and inspect a useable gasket to determine if it may be reinstalled and put back into service.
Furthermore, the foregoing discussion discloses and describes merely exemplary embodiments of the present invention. One skilled in the art will readily recognize from such discussion, and from the accompanying drawings and claims, that various changes, modifications and variations may be made therein without department from the spirit and scope of the invention as defined in the following claims.

## Claims

1. An axle assembly comprising:
a housing;
a differential assembly rotatably supported within said housing;
a differential cover; and
a gasket assembly including a body and a magnet coupled to said body, said gasket assembly disposed between said housing and said differential cover to seal an interior of said housing from an external environment, wherein said magnet is positioned in communication with a lubricant located within said interior of said housing.

2. The axle assembly of claim 1 wherein said gasket body is substantially rigid and is shaped as a closed loop.

3. The axle assembly of claim 1 wherein the gasket body includes an aperture within which said magnet is retained.

4. The axle assembly of claim 1 wherein the magnet is operable to attract undesirable metallic particles located in the lubricant.

5. The axle assembly of claim 4 including fasteners for securing said magnet to said body of said gasket assembly.

6. The axle assembly of claim 1 further including an elastomer coupled to said body, said elastomer in engagement with one of said housing and said differential cover.

7. The axle assembly of claim 1 further including a ring gear coupled to said differential assembly, wherein said ring gear is at least partially submersed in said lubricant, and wherein said magnet is positioned within said interior of said housing to be in proximity to said ring gear.

8. The axle assembly of claim 1 wherein said gasket assembly includes a tab to indicate a desired orientation of said gasket assembly relative to said housing.

9. The axle assembly of claim 1 wherein said gasket assembly includes a plurality of mounting apertures, at least one of said mounting apertures having a fastener extending therethrough for removably securing said differential cover to said housing.

10. A drive axle assembly, comprising:
a housing;
a pinion shaft rotatably supported by said housing;
a differential assembly rotatably supported by said housing and driven by said pinion shaft;
a differential cover; and
a gasket assembly including a body portion positioned between said housing and said differential cover and a magnet positioned within a cavity defined by said housing and said differential cover, said magnet in communication with a lubricant located within said cavity.

11. The drive axle assembly of claim 10 wherein said magnet is secured to said body portion of said gasket assembly.

12. The drive axle assembly of claim 10 wherein said body portion of said gasket assembly forms a closed ring.

13. A gasket assembly for a power transfer assembly having a housing, a gearset rotatably supported in a cavity defined by the housing, a cover pan coupled to the housing for providing access to the gearset, and a lubricant located within the cavity, the gasket assembly comprising:
a body portion having a first planar surface adapted to engage the cover pan and an opposite second planar surface adapted to engage the housing;
an elastomer coupled to one of said first and second planar surfaces; and
a magnet coupled to said body portion, said magnet adapted to attract metallic particles suspended within the lubricant located within the cavity of the housing.

14. The gasket assembly of claim 13 wherein said elastomer is coupled to both of said first and second planar surfaces.

15. The gasket assembly of claim 13 wherein said body portion includes an aperture extending therethrough within which said magnet is disposed.

16. The gasket assembly of claim 15 including fasteners for interconnecting said magnet and said body portion.

17. A power transfer assembly, comprising:
a housing defining a cavity;
a gearset supported for rotation in said cavity of said housing;
a cover adapted to be secured to said housing to enclosed said cavity; and
a gasket assembly disposed between said housing and said cover to define a fluid-tight seal therebetween and maintain lubricant in a sump portion of said cavity, said gasket assembly having a body portion and a magnet secured to said body portion, said magnet is in communication with said lubricant within said sump portion of said cavity.

18. The power transfer assembly of claim 17 wherein said body portion of said gasket assembly is a ring having an aperture formed therein, and wherein said magnet is secured to said body portion adjacent to said aperture.

19. The power transfer assembly of claim 18 wherein said aperture is positioned below the surface of said lubricant such that said magnet functions to attract magnetic particles suspended in said lubricants.

20. The power transfer assembly of claim 17 wherein said gearset is a differential assembly.