FIELD OF THE INVENTION

[0001] The invention relates to differential structures for a motor vehicle.

BACKGROUND OF THE INVENTION

[0002] Generally in an open mode, a differential is configured to allow two wheels on a motor vehicle to operate at different speeds. In a locked mode, the two wheels are locked so that they rotate at the same speed. The differential may include two halves with the pinion and bevel gears positioned therein. Typically a ring gear may be attached to one of the halves using bolts.

[0003] It would be desirable to have the ring gear and both halves of the differential coupled without the use of multiple fasteners to both lighten the weight of the differential, as well as improve the torque transfer ability of the differential.

SUMMARY OF THE INVENTION

[0004] In one aspect, there is disclosed a differential assembly that includes a first half including a bell shaped housing having a first half flange including a plurality of first half key sections formed thereon separated by a plurality of first half notches formed in the first half flange. A second half includes a body having a second half flange including a plurality of second half key sections formed thereon separated by a plurality of second half notches formed in the second half flange. The first half key sections are positioned in the second half notches and the second half key sections are positioned in the first half notches rotatively coupling the first half and second half of the differential assembly.

[0005] In another aspect, there is disclosed a differential assembly that includes a first half including a bell shaped housing having a first half flange including a plurality of first half key sections formed thereon separated by a plurality of first half notches formed in the first half flange. A second half includes a body having a second half flange including a plurality of second half key sections formed thereon separated by a plurality of second half notches formed in the second half flange. The first half key sections are positioned in the second half notches and the second half key sections are positioned in the first half notches rotatively coupling the first half and second half of the differential assembly. A ring gear is disposed about the bell shaped housing and positioned adjacent the first half flange and second half flange defining a weld interface and a weld bead formed about the weld interface. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 is a partial perspective view of one half of a differential case;

[0007] Figure 2 is a partial perspective view of another half of a differential case

[0008] Figure 3 is a partial perspective view of a differential including two halves of a differential case and a ring gear;

[0009] Figure 4 is a partial perspective view of a differential including two halves of a differential case a ring gear and a weld bead;

[0010] Figure 5 is a partial perspective view of a differential including two halves of a differential case;

[0011] Figure 6 is a partial perspective view of a differential including two halves of a differential case.

DETAIFED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Generally, for a vehicle, torque may be provided by an engine to a transmission to a power transfer unit to a drive shaft to a pinion gear to a ring gear around a differential case to a pinion shaft within the differential. As the pinion shaft rotates the meshed pinion gears there is a transfer of differentiated or undifferentiated torque to side gears. The side gears may transfer torque to drive axles. Torque is then transferred to the wheels of the vehicle.

[0013] Referring to Figures 1-6, the differential assembly 10 includes a two piece differential case 12 having a first half 14 and a second half 16.

[0014] Referring to Figure 1, the first half 14 may include a bell shaped housing 18 that houses the pinion and side gears. The bell shaped housing 18 includes a base portion 20 that extends to a side wall 22. The side wall 22 extends from the base portion 20 and terminates at a first half flange 24. The first half flange 24 includes first half key sections 26 disposed circumferentially around the first half flange 24. The first half key sections 26 are separated from each other by first half notches 28 formed in the first half flange 22. In the depicted embodiment, there are four first half key sections 26 separated by four first half notches 28. It should be realized that various numbers of first half key sections 26 and notches 28 may be utilized. In one aspect, there may be a plurality of first half key sections 26 and notches 28. The first half 14 includes connection bores 30 formed therein for receiving a fastener 32, as will be described in more detail below.

[0015] Referring to Figure 2, the second half 16 of the differential case 12 includes a body 34 having a base 36 that extends to a sidewall 38. The sidewall 38 terminates at a second half flange 40. The second half flange 40 includes second half key sections 42 disposed

circumferentially around the second half flange 40. The second half key sections 42 are separated from each other by second half notches 44 formed in the second half flange 40. In the depicted embodiment, there are four second half key sections 42 separated by four second half notches 44. It should be realized that various numbers of second half key sections 42 and notches 44 may be utilized. In one aspect, there may be a plurality of second half key sections 42 and notches 44. The second half 16 includes connection bores 30 formed therein for receiving a fastener 32, as will be described in more detail below.

[0016] Referring to Figures 3 and 4, the differential assembly 10 includes a ring gear 46 disposed about the bell shaped housing 18 and coupled to the first and second halves 14, 16. The ring gear 46 is disposed adjacent the flanges 24, 40 of the first and second halves 14, 16.

[0017] Referring to Figures 3-6, when assembled, the ring gear 46 is positioned about the bell housing 18 of the first half 14. The key sections 26 of the first half 14 are received in the notches 44 of the second half 16. Similarly, the key sections 42 of the second half 16 are received in the notches 28 of the first half 14. In this manner, the first half 14 and second half 16 are rotatively coupled to transfer torque more efficiently than prior art designs including only fasteners.

[0018] Fasteners 32 may be used to temporarily couple the first and second halves 14, 16 prior to a welding operation. The alternating key sections 26, 42 of the first and second halves 14, 16 in conjunction with the notches 28, 44 of the first and second halves 14, 16 when assembled define a weld interface section 48 with the ring gear 46.

[0019] A continuous weld bead 50 may be formed about the weld interface section 48 such that the ring gear 46, first half 14 and second half 16 are joined by a single weld bead 50.

Various welds such as electron beam welding and laser welds may be utilized.

[0020] The interlocking of the first and second halves 14, 16 and the application of a weld bead 50 joining the first and second halves 14, 16 and the ring gear 46 eliminates fasteners that are typically used to join the ring gear to one half of a differential case. In this manner, a weight savings in comparison to prior art differentials is realized. Additionally, the interlocking of the first and second halves 14, 16 provides an improved torque transfer within the differential in comparison to prior art designs that utilize only fasteners to transfer torque.