Stainless steel running surface on a plastic deflector

A differential for a rear wheel drive vehicle is previewed comprising a differential case for rotationally supporting and housing a pinion shaft with the pinion shaft extending axially through an opening in the differential case. A pinion seal extends around the pinion shaft and has an outer edge abutting a cavity wall defining the opening in the differential case. The pinion seal has an axial lip projecting in an axial direction. A plastic deflector has a discshaped main body formed of a plastic material, a passageway extending through the plastic deflector, and a stainless steel ring fixedly coupled to the disc-shaped main body providing a stainless steel running surface. The plastic deflector is assembled on the pinion shaft such that the pinion shaft extends through the deflector passageway and the stainless steel running surface abuts the axial lip of the pinion seal.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a differential for a vehicle having rear drive wheels. More specifically, the present invention relates to a deflector covering a pinion seal.

2. Description of Related Art

In vehicles that have rear drive wheels, drive shafts and differentials are used to transmit power from the engine and transmission of the vehicle to the wheels. The drive shafts are used to transmit power from the transmission to the differential. The differential is housed in a differential case and each differential has a pinion shaft and pinion gear that attaches to the drive shaft inside the differential case to transfer the power from the drive shaft to the drive wheel. Each pinion shaft has a pinion seal extending around the pinion shaft that is used to seal differential fluid (oil) from leaking out of the differential case. The pinion seal includes an axial lip. A stainless steel deflector ring is pressed between the differential case and the pinion shaft to abut against the axial lip of the pinion seal to seal the differential fluid within the differential case. However, the stainless steel ring is costly and causes galvanic corrosion problems in the differential.

Therefore, it is desirable to provide an improved seal between the shaft and differential case. Further, it is desirable to provide a deflector ring having a lower cost than the stainless steel deflector ring. Finally, it is desirable to reduce the galvanic corrosion problems in the differential caused by the stainless steel deflector ring.

SUMMARY OF THE INVENTION

A differential for a rear wheel drive vehicle is provided comprising a differential case for rotationally supporting and housing a pinion shaft with the pinion shaft extending axially through an opening in the differential case. A pinion seal extends around the pinion shaft and has an outer edge abutting a cavity wall defining an opening in the differential case. The pinion seal has an axial lip projecting in an axial direction. A plastic deflector has a disc-shaped main body formed of a plastic material, a passageway extending through the plastic deflector, and a stainless steel ring fixedly coupled to the disc-shaped main body providing a stainless steel running surface. The plastic deflector is assembled on the pinion shaft such that the pinion shaft extends through the deflector passageway and the stainless steel running surface abuts the axial lip of the pinion seal.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Referring to the Figures, wherein like numerals indicate like or corresponding parts throughout the several views, a portion of a differential10for a rear wheel drive vehicle is shown inFIG.1, illustrating one embodiment of a plastic deflector20with a stainless steel running surface30. The differential10includes a differential case38for rotationally supporting and housing a pinion shaft40. The pinion shaft40extends axially through an opening50in the differential case38to connect with and drive the rear wheels of the vehicle. The differential case38may also include a rim54extending circumferentially around the opening50.

Referring toFIG.1, a pinion seal60extends around the pinion shaft40and abuts a cavity wall50A defining the opening50in the differential case38. It is known to provide the pinion seal60between the pinion shaft40and the differential case38to prevent the oil from leaking out of the differential case38. The pinion seal60is configured to cover the opening50in the differential case38around the pinion shaft40.

An exploded view of the portion of the differential10ofFIG.1is illustrated inFIG.2. The pinion seal60typically has an inner edge62configured to abut the pinion shaft40, a seal main body portion64extending radially between the inner edge62and an outer edge68of the pinion seal60, an axial lip70extending from an upper surface72of the seal main body portion64towards an upper lip edge76, and an outer cylindrical wall78configured to frictionally engage with the cavity wall50A of the opening50in the differential case38. Further, the inner edge62of the pinion seal60defines a passageway62A extending through the pinion seal60.

The pinion seal68can have a variety of configurations depending on the specific requirements of an end application. Typically, the pinion seal60extends between the outer wall50A of the opening50and the pinion shaft40. Optionally, the pinion seal60can extend around the outer rim54on the opening50of the differential case38. Regardless of the geometry of the pinion seal68, it is desirably that the stainless steel running surface30of the plastic deflector20abuts the axial lip70to form a seal between the plastic deflector20and the pinion seal60.

As illustrated inFIG.2, the pinion seal68is assembled with the pinion shaft40by pressing the pinion seal68into the opening50in an axial direction84of the pinion shaft40until the outer cylindrical wall78abuts the cavity wall50A in the differential case38, as indicated by arrow A1.

Returning toFIG.1, the plastic deflector20is assembled on the pinion shaft40such that the stainless steel running surface30abuts the axial lip70of the pinion seal68. A flange100is assembled with the pinion shaft40such that the flange100frictionally engages with and abuts the plastic deflector20, as illustrated inFIG.1. Referring toFIG.2, the flange100has a generally cylindrically-shaped main body106with a flange passageway110extending axially through the flange100. The passageway110is configured to matingly engage with the pinion shaft40via a threaded connection, a splined connection, or the like.

A cross-sectional view and a side view are shown inFIGS.3and4, respectively, of one embodiment of the plastic deflector20. Referring toFIGS.2through4, the plastic deflector20has a generally disc-shaped main body116extending between an upper surface118A and a lower surface118B and bounded by an outer cylindrically-shaped surface120. Further, the plastic deflector20has an inner cylindrical wall130extending in an axial direction84between the upper and lower surfaces118A,118B defining a passageway140through the plastic deflector20. The disc-shaped main body116comprises a plastic portion150formed of a plastic material. Preferably, the plastic portion150is formed from a glass-filled plastic material. However, selection of a specific plastic material, including a desired percentage of glass fill, is based in part on the operating conditions of the intended application as well as based on other factors such as requirements by original equipment manufacturers (OEM), cost, durability, and the like.

Referring toFIGS.3and4, the plastic deflector20includes a stainless steel washer or ring160fixedly coupled to the disc-shaped main body116. The stainless steel ring160can be mechanically locked into position, mechanically fastened to the plastic portion150, molded-in, or embedded into the plastic portion150during a molding process. The stainless steel ring160has a first cylindrical surface170defining an inner diameter170of the ring160, a second cylindrical surface180defining an outer diameter180of the ring160, and opposing upper and lower surfaces190,30. The lower surface30of the ring160provides the stainless steel running surface30against the axial lip70of the pinion seal60. The plastic portion150surrounding the ring160provides a cost and weight savings, as well as an ease of manufacturability of the plastic deflector20while increasing the contamination exclusion capabilities of the pinion seal60. A majority of the novel deflector20is made of plastic except where the axial lip70contacts the ring160of the novel deflector20. The ring160is preferably made of a stainless steel so the axial lip70does not wear through the plastic deflector20.

Returning toFIG.2, the plastic deflector20is optionally assembled with the flange100as illustrated by arrow A2. The inner cylindrical wall130and the passageway140of the plastic deflector20are configured such that the plastic deflector20can be pressed onto one end194of the flange100for form a flange/deflector assembly196. As show inFIG.2, the flange100includes a recessed ledge200extending circumferentially around the flange100configured to frictionally engage with the inner cylindrical wall130of the plastic deflector20. As illustrated by arrow A3shown inFIG.5, after the plastic deflector20is assembled with the flange100, the flange/deflector assembly196is assembled with the pinion shaft40to form the differential10shown inFIG.1. The plastic deflector20compresses the axial lip70of the pinion seal60to form a seal between the stainless steel running surface30and the axial lip70. Preferably, the axial lip70is compressed between about 0.8 mm and about 1.2 mm during the assembly process shown inFIG.5. However, in alternate embodiments, the plastic deflector20can compress the axial lip70more or less than between about 0.8 mm and about 1.2 mm, including the plastic deflector20optionally being spaced apart from the upper surface72of the axial lip70.

A second embodiment of the plastic deflector20-1is shown inFIGS.6and7.FIG.6illustrates an alternate assembly method for assembling the plastic deflector20-1with the pinion shaft40. The pinion seal68is assembled with the pinion shaft40as illustrated by arrow B1. The plastic deflector20-1is configured to be directly assembled with the pinion shaft40, as illustrated by arrow B2, after the pinion seal60is assembled with the pinion shaft40. The second embodiment of the plastic deflector20-1, shown inFIGS.6and7, is configured to be pressed onto the pinion shaft40. Alternatively, the plastic deflector20-1can be assembled with the pinion shaft40such that the inner cylindrical wall130-1of the plastic deflector20-1does not frictionally engage with the pinion shaft40. In addition, the inner cylindrical wall130-1can be replaced with a non-cylindrical surface if desired for assembling with the pinion shaft40. For example,FIG.7illustrates the inner wall130-1of the plastic deflector20-1having a splined shape130-2configured to matingly engage with a splined shaft surface40A on the pinion shaft40. Also shown inFIG.6, the flange100is assembled with the pinion shaft40as illustrated by arrow B3after the pinion seal68and the plastic deflector20-1are assembled with the pinion shaft40.

A third embodiment of the plastic deflector20-2is illustrated inFIG.8. As with the plastic deflectors20,20-1shown inFIGS.1-7, the third embodiment includes a generally disc-shaped main body116A extending between opposing upper and lower surfaces118A′,118B′ and bounded by an outer cylindrically-shaped surface120′. Further, the plastic deflector20-2has an inner cylindrical wall130A,130B extending in an axial direction84defining a passageway140′ through the plastic deflector20-2. The plastic deflector20-2comprises a plastic portion150′ and a stainless steel ring160′ fixedly coupled to the plastic portion150′. The ring160′ has opposing upper and lower surfaces190′,30′ extending between inner and outer cylindrical walls170′,180′. The lower surface30′ of the ring160′ provides the stainless steel running surface30′ configured to frictionally engage with the axial lip70of the pinion seal60. The inner cylindrical walls130A,130B are configured to matingly engage and/or frictionally engage with the pinion shaft40. As with the second embodiment, the inner cylindrical walls130A,130B can be non-cylindrical. For example, the inner cylindrical walls130A,130B can be a single cylindrical wall130A,130B, offset walls130A,130B, a splined shaped profile such as illustrated in the embodiment shown inFIG.7, or another shape configured to engage with a specific pinion shaft40.

As an alternative, the embodiment shown inFIG.8illustrates a plastic deflector20-2having a rim300projecting away from the lower surface118B′ of the disc-shaped main body116A in the axial direction84. The rim300extends circumferentially around the disc-shaped main body116A. The outer surface120′ of the disc-shaped main body116forms an outer surface120′ of the rim300. The rim300has an inner surface310configured to be spaced apart from an outer edge68of the pinion seal60. Further, the inner surface310of the rim300is configured to be spaced apart from the rim54surrounding the opening50in the differential case38. The rim300extends in the axial direction84away from the disc-shaped main body116A of the plastic deflector20-2. Further, the rim300is configured to span an axial gap between the disc-shaped main body116A and the differential case38when the plastic deflector20-2is assembled with the pinion shaft40and the differential case38.

The plastic deflector20-2ofFIG.8is shown assembled with the differential10′ inFIG.9. As with the prior embodiments of the plastic deflector20,20-1, the third embodiment of the plastic deflector20-2is assembled with the pinion shaft40such that the stainless steel running surface30′ frictionally engages with the upper surface72of the axial lip70of the pinion seal60. Preferably, the stainless steel running surface30′ of the plastic deflector20-2compresses the upper surface72of the axial lip70between about 0.8 mm and about 1.2 mm to ensure a suitable seal between the axial lip70and the plastic deflector20-2.

Also shown inFIG.9, the rim300of the plastic deflector20-2extends around the rim54of the differential case38. In specific, the inner surface310of the rim300is spaced apart from the rim54of the opening50to the differential case38. Further, the inner surface310of the rim300is spaced apart from the outer periphery68of the pinion seal60. Various embodiments of the plastic deflector20,20-1,20-2can include the optional rim300and can include other profiled surfaces to provide desired coverage around the pinion seal60. The selection of the overall dimensions, material composition, and shape of the plastic deflector20,20-1,20-2is chosen in part due to the operating conditions of the intended differential10,10′. Likewise, various embodiments of the plastic deflector20,20-1,20-2are configured to be assembled with the pinion shaft40as required for specific applications.

Each embodiment of the plastic deflector20,20-1,20-2includes the stainless steel running surface30,30′ integrated within the plastic portion150,150′. The plastic deflector20,20-1,20-2comprises mostly a plastic material, and as such has a lower cost than a typically known stainless steel deflector400shown inFIG.10.FIG.10illustrates a cross-sectional view of a portion of a known differential10B for a rear wheel drive vehicle. The known differential10B includes a differential case38B for rotational supporting and housing a pinion shaft40B. The pinion shaft40B extends axially through an opening50B in the differential case38B to connect with and drive the rear wheels of the vehicle. The known differential case38B includes a rim54B extending around an outer periphery50C of the opening50B. A pinion seal60B extends around the pinion shaft40B and abuts a cavity wall50C defining the opening50B in the differential case38B. The pinion seal60B includes an axial lip70B extending in an axial direction84B from an upper surface72B of the pinion seal60B.

The known stainless steel deflector400shown inFIG.10includes a disc-shaped main body410having a recessed channel420extending circumferentially around the known stainless steel deflector400. The channel420is configured such that a lower surface430of the channel420is spaced apart from the axial lip70B of the pinion seal60B when the known deflector400is assembled with the pinion shaft40B and the pinion seal60B. A flange100B is assembled with the pinion shaft40B such that a lower surface194B of the flange100B abuts the stainless steel deflector400.

The channel420forms a non-contact labyrinth-type seal with the axial lip70B of the pinion seal60B. Non-contact labyrinth-type seals typically are configured to have a controlled clearance with the axial lip70B of the pinion seal60B to minimize leakage of oil and minimize intrusion of contamination. Some known stainless steel deflectors400are configured such that the inner surface430of the main body410compresses the axial lip70B to form a physical seal between the known stainless steel deflector400and the pinion seal60B.

In addition, the known stainless steel deflector400shown inFIG.10includes a rim440extending in the axial direction84B away from the main body410of the known deflector400. The rim440is configured such that the rim440is spaced apart from the outer edge68B of the pinion seal60B and spaced apart from the rim54B extending around the opening50B to the differential case38B when the known deflector400is assembled with the pinion shaft40B.

However, the known stainless steel deflectors400have a higher material cost than the novel plastic deflectors20,20-1,20-2shown inFIGS.1-9since the known stainless steel deflectors400comprise solely stainless steel. The novel plastic deflectors20,20-1,20-2have a reduced material cost over the known stainless steel deflectors400since the novel plastic deflectors20,20-1,20-2comprise mostly a plastic material.

Further, the known stainless steel deflectors400can cause galvanic corrosion within the differential10B. The novel plastic deflectors20,20-1,20-2reduce the probability of developing galvanic corrosion within the differential10,10′ since the plastic deflectors20,20-1,20-2include less stainless steel material than is included within the known stainless steel deflectors400. The plastic deflectors20,20-1,20-2include a stainless steel ring160,160′ fixedly coupled to the plastic portion150,150′ of the novel deflector20,20-1,20-2to provide a wear surface30,30′. The amount of stainless steel material within the stainless steel ring160,160′ is significantly less than the amount of stainless steel material in the known stainless steel deflector400. This reduction in the amount of stainless steel material in the novel plastic deflector20,20-1,20-2reduces the cost and weight over the known stainless steel deflector400as well as reducing the amount of galvanic corrosion induced in the differential10,10′.

Finally, it should be appreciated that the novel plastic deflector20,20-1,20-2may be utilized to seal between any axial shaft and housing such as any drive shaft and casing in a driveline or transmission of an automotive vehicle.

One benefit of the plastic deflector20,20-1,20-2having the stainless steel running surface30,30′ is the plastic deflector20,20-1,20-2has a lower cost than typical known stainless steel deflectors400since the plastic deflector20,20-1,20-2comprises mostly a plastic material. A second benefit is the plastic deflector20,20-1,20-2forms an improved seal between the pinion shaft40and the differential case38since the stainless steel running surface30,30′ is configured to abut and compress the axial lip70of the pinion seal60. A third benefit is a reduction in galvanic corrosion within the differential10since the plastic deflector20,20-1,20-2only has stainless steel forming the stainless steel running surface30,30′ with the remainder of the plastic deflector20,20-1,20-2being formed of a plastic material.