TECHNICAL FIELD

The present description relates generally to a differential in a vehicle. More particularly, the present disclosure relates to a differential with lubricant distribution features.

BACKGROUND & SUMMARY

Vehicle differentials, such as open differentials, permit speed differentiation between axle shafts which deliver power to drive wheels. Wheel slip during vehicle cornering is avoided when speed differentiation between the axle shafts is permitted. However, in low traction environments, the open differential permits the drive wheel with a lower friction coefficient to rotate at a higher speed than the opposing wheel, resulting in wheel slip.

A desire to increase vehicle traction led to the development of limited slip differentials. This limited slip functionality allows the deviation between axle shaft speeds to be constrained to reduce the chance of wheel slip. To alter handling performance under variable traction conditions, these limited slip differentials may transfer a greater amount of torque to the drive wheel with less traction. One example limited slip differential is shown by Yamazaki et al. in U.S. Pat. No. 7,029,415 B2. Yamazaki teaches a differential with a case and a plurality of pinion gears that mesh with a pair of side gears. Yamazaki further provides a lubricant hole in the case in an attempt to direct oil to the gears housed therein.

The inventors herein have recognized potential issues with Yamazaki's limited slip differential and other differential systems. As one example, the pinion gears disclosed by Yamazaki may exhibit unbalanced gear meshing due to the asymmetric tooth arrangement of the gears, leading to uneven wear amongst the gears. Further, the single lubrication hole in Yamazaki's differential may not achieve balanced lubricant distribution within a differential case and may be unable to flow desired amounts of lubricant to targeted regions that experience higher loads, for example. The potential for uneven wear of the differential components is consequently increased, thereby decreasing the differential's lifespan.

To overcome at least some of the aforementioned challenges, a differential is provided. In one example, the differential comprises two sets of pinion gears. Each of the gears in each set of pinions includes an untoothed section positioned between a wider toothed section and a narrower toothed section. The differential further includes a first side gear that meshes with the wider toothed sections of the first set of pinion gears. Still further, the differential includes a second side gear that meshes with the wider toothed sections of the second set of pinion gears. The differential further includes a case that comprises a lubrication port. The lubrication port opens radially adjacent to one of the pinion gears in the first set of pinion gears. In this example, during a drive state, an axial load on the first side gear is in an inboard direction. In this way, the position of the lubrication port in the case of the differential allows lubricant to be delivered to a targeted region of the differential which may experience higher loads, thereby decreasing wear on the gearing system and increasing differential longevity.

As one example, the differential case may include a plurality of lubrication ports. In this example, each lubrication port opens radially adjacent to a separate pinion gear in a first set of pinion gears. In this way, the lubrication ports provide more balanced lubricant distribution. Consequently, the potential for uneven wear on the gearing system is decreased which may further increase differential longevity.

As another example, the differential case may comprise a continuous (e.g., monolithic) structure, which may increase the overall strength and reliability of the differential. Further, structuring the case in this manner reduces the overall number of parts of the differential. The differential's manufacturing duration may be decreased, as a result.

It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.

