MXPA06001430A - Pinion support for a differential assembly - Google Patents

Abstract

A differential assembly (10) includes a yoke (12), attached to a drive shaft (13), for driving a pinion head (14). The differential assembly (10) further includes inner and outer pinion bearing assemblies (16, 18), a separable mounting plate (20), and a cavity defined by a housing (22) for receiving a pinion assembly (15). The outer pinion bearing assembly (18) is integrally mounted to the housing (22), while the inner pinion bearing assembly (16) is secured to the separable mounting plate (20). The pinion head (14) is straddle mounted between the inner and outer pinion bearing assemblies (16, 18).

Description

PINON SUPPORT FOR A DIFFERENTIAL ASSEMBLY Technical Field The present invention relates to an improved pinion support for a differential assembly and in particular to a pinion support for a straddle drive axle.

Background of the Invention Differentials are used in the driving lines of many modern vehicles. Commonly, a differential takes a rotary input and drives two axes that extend in opposite directions. The differential allows the two axes to rotate at different speeds one in relation to the other.

Brief Description of the Invention The present invention relates to a differential assembly comprising a fork, attached to a drive shaft, for driving a pinion head. The differential assembly further includes internal and external pinion bearing assemblies, a removable mounting plate, and a cavity defined by a housing for receiving a pinion assembly. The external pinion bearing assembly is integrally mounted to the housing, while the internal pinion bearing assembly is secured to the mounting plate. The pinion head is straddled between the internal and external pinion bearing assemblies.

Brief Description of the Drawings The present invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a perspective view of a differential assembly assembled within a vehicle according to the present invention. Figure 2 is a cross-sectional view of a differential assembly according to an embodiment of the present invention. Figure 3 is a cross-sectional view of a differential assembly according to an alternate embodiment of the present invention.

Description of the Preferred Modality Referring to Figure 1, a differential assembly 10 is shown assembled within the vehicle 11. Focusing on Figure 2, the differential assembly 10 is illustrated in accordance with the present invention. The differential assembly 10 comprises a fork 12 attached to a drive shaft 13, for driving a pinion head. The differential assembly 10 further includes a pinion assembly 15. The pinion assembly 15 includes gear teeth 14a, internal and external pinion bearing assemblies 16, 18 and shaft 13. The pinion assembly 15 is received within a cavity 21 defined by a housing 22; the housing 22 is fixed against rotation. The internal pinion bearing assembly 16 of the pinion assembly 15 is secured to a removable mounting plate 20. The pinion head 14 is straddled between the internal and external pinion bearing assemblies 16, 18 for optimum support. The pinion head 14 it is mounted directly to the drive shaft 13 and supported on each side by the two pinion bearing assemblies 16, 18 axially spaced apart. The internal pinion bearing assembly 16 supports the drive shaft portion 13 which is located within the housing 22. The outer pinion bearing assembly 18 supports the portion of the drive shaft 13 with which the drive shaft of the vehicle is normally associated. The pinion head 14 mounted astride between the internal and external pinion bearing assemblies 16, 18 decreases the number of bearing assemblies found in conventional differential assemblies by allowing the pinion head 14 to be optimally supported. In addition, the lubrication of the inner and outer pinion bearing assemblies 16, 18 is provided without the need for additional oil channels, thereby reducing the complexity of the differential assembly 10. The internal and external pinion bearing assemblies 16 , 18 each further comprise an inner bearing ring 24, 26, an outer bearing ring 28, 30 and a bearing 32, 34, respectively. The bearings 32, 34 are placed between the inner bearing rings 24, 26 and the outer bearing rings 28, 30. The inner bearing ring 26 of the outer bearing assembly 18 splices an engaging teeth face 14a of the pinion head 14. The outer bearing ring 28 of the inner bearing 16 is mounted on the removable mounting plate 20, while the other outer bearing ring 30 of the outer pinion bearing assembly 18 is integrally mounted to the housing 22. When mounting the outer bearing ring 30 of the outer bearing assembly 18 directly to the housing 22, the outer bearing assembly 18 provides a stiffer structure for holding the pinion head 14 than conventional differential assemblies. In addition, the mounting distance of the pinion head 14 can be easily machined for tolerance through the machining of the housing 22 wherein the outer bearing ring 30 connects the housing 22. Accordingly, the outer pinion bearing assembly 18 can be assembled within the differential assembly 10 without the use of wedges or a pack of wedges, resulting in weight savings and cost reduction compared to conventional differential assemblies. In addition, the connection of the external pinion bearing assembly 18 directly to the housing 22 eliminates the need for a pinion bearing housing, or external regulator, as found in conventional differential assemblies. Commonly, the bearing housings create an additional path for the oil to drain out of the housing 22. Therefore, by eliminating the need for a bearing housing, there is no additional path through which the oil drips. In addition, the removal of the bearing housing reduces the fork protrusion dimension H. The reduced fork dimension H reduces the amount of space required for the differential assembly 10 within the vehicle. Additionally, the reduced fork clearance dimension H provides a significant advantage for driving line angles of small wheelbase vehicles (not shown) and for driving line angles between tandem axles (not shown). By way of example, and without limitation, Figures 2 and 3 illustrate the outer pinion bearing assembly 18 which is longer than the internal pinion bearing assembly 16. In general, the outer pinion bearing assemblies support substantially the load of the pinion head within the differential assemblies. Consequently, the external pinion bearing assemblies are normally longer than the internal pinion bearing assemblies. However, it can be seen that the Internal and external pinion bearing assemblies 16, 18 can be substantially of the same dimensions. Additionally, the bearings 32, 34 can be formed symmetrically, as shown in Figure 1, or the bearings 32, 34 can be tapered at one end. The internal pinion bearing assembly 16 is mounted on a detachable mounting plate 20. Figures 2 and 3 illustrate embodiments in which the mounting plate 20 can be fixed and removed from the housing 22 through a series of bolts. 42. It can be appreciated that the present invention can be practiced with any number of bolts to secure the removable mounting plate 20 to the housing 22. Figure 1 illustrates a method for fixing the preloaded pinion assembly bearing 15 for pinion bearing assemblies internal and external 16 and 18. However, the present invention is not limited to the use of bolts to secure the removable mounting plate 20 to the housing 22. For example, the mounting plate 20 can be secured to the housing 22 through a adhesive, or by means of a press fit design. To fix the preloaded internal and external pinion bearings 16 and 18, a pack of wedges 43 can be placed under the mounting plate 20 of the internal pinion bearing assembly 16. The pinion assembly 15 can be received within the cavity 21 from the rear portion 40 of the housing 22. Currently, the pinion assemblies are received within the cavity 21 of the housing 22 through an opening defined by the dimension D. Therefore, the dimension D must be sufficiently wide to accommodate the portion wider of the pinion assembly 15. However, with the pinion assembly 15 being assembled through the rear portion 40 of the housing 22, the dimension D can be decreased. The result is a more compact housing 22. In addition, the structural integrity of the housing 22 is improved due to the reduced size of the opening D. Additionally, the need for separable covers or bearing carriers is eliminated along with the added cost and potential for oil run-off. Figure 3 illustrates an alternate embodiment of the present invention. The differential assembly 10 'substantially incorporates the characteristics of the differential assembly 10 of Figure 1. However, the outer bearing ring 28 of the internal pinion bearing assembly 16 has a threaded groove 44. The outer bearing ring 28 of the internal pinion bearing assembly 16 can be screwed into a desired position to preload the pinion bearing assemblies 16, 18. Accordingly, the threaded groove 44 eliminates the need for a wedge pack 43 to preload the inner and outer bearing assemblies 16, 18. In addition, the internal pinion bearing assembly 16 can include a safety ring 46. and a post 48. The safety ring can be riveted to the threaded groove 44 and attached to the post to prevent the threaded groove 44 from rotating once the preload has been set. However, it will be appreciated that the present invention is not limited to the safety ring and post in order to prevent the threaded groove from rotating. By way of example, and without limitation, the threaded rib 44 can be coated with an adhesive to prevent rotation once the preload has been established. While the invention has been specifically described in relation to certain specific embodiments thereof, it is understood that this is only by way of illustration and not limitation and the scope of the appended claims will be construed as broadly as will be previous technique.

Claims (18)

1. A differential assembly comprising: a fork, attached to a drive shaft, for driving a pinion head; internal and external pinion bearing assemblies; a removable mounting plate, the mounting plate which is secured to the internal pinion bearing assembly; a cavity defined by a housing for receiving a pinion assembly; wherein the external pinion bearing assembly is integrally mounted within the housing, wherein the internal pinion bearing assembly includes an adjustment mechanism; and wherein the pinion assembly is straddled between the internal and external pinion bearing assemblies.

2. A differential assembly according to claim 1, characterized in that the mounting plate of the internal pinion bearing assembly is secured to the housing through at least one bolt.

3. A differential assembly according to claim 1, characterized in that each of the internal and external pinion bearing assemblies comprises an internal bearing ring, an outer bearing ring and a bearing positioned between the bearing rings.

4. A differential assembly according to claim 1, characterized in that the adjustment mechanism includes a threaded groove. A differential assembly according to claim 1, characterized in that the adjustment mechanism includes at least one wedge package, and wherein the mounting plate can be wedged by means of said at least one wedge package that is placed under the mounting plate. 6. A differential assembly according to claim 1, characterized in that a mounting distance for the pinion head can be established by machining the housing. 7. A differential assembly comprising: internal and external pinion bearing assemblies; a removable mounting plate, the mounting plate which is secured to the internal pinion bearing assembly; a cavity defined by a housing for receiving a pinion assembly; wherein the external pinion bearing assembly is integrally mounted within the housing, wherein the internal pinion bearing assembly includes a threaded groove; and wherein the pinion assembly is straddled between the internal and external pinion bearing assemblies. 8. A differential assembly according to claim 7, characterized in that the threaded groove can be threaded to a desired position to preload the inner and outer pinion bearing assemblies. A differential assembly according to claim 7, characterized in that the internal pinion bearing assembly further comprises a safety ring and a post, wherein the safety ring is secured to the post to prevent rotation of the threaded groove . A differential assembly according to claim 7, characterized in that the mounting plate of the internal pinion bearing assembly is secured to the housing through at least one bolt. 11. A differential assembly according to claim 7, characterized in that each of the internal and external pinion bearing assemblies comprises an inner bearing ring, an outer bearing ring and a bearing positioned between the inner and outer bearing rings. 12. A differential assembly according to claim 7, characterized in that the mounting plate can be wedged through at least one wedge package placed below the mounting plate. A differential assembly according to claim 7, characterized in that a mounting distance for the pinion head can be established through machining of the housing. 14. A differential assembly comprising: a carrier housing having a first opening and a second opening; an external pinion bearing assembly integrally mounted within the carrier housing in the first opening; an internal pinion bearing assembly positioned in said second opening; a pinion assembly mounted between the outer pinion bearing and the internal pinion bearing; wherein the internal pinion bearing is fixed to a removable mounting plate in the second opening of the carrier housing; and wherein the pinion assembly is installed through the second opening. 1

5. A differential assembly according to claim 14, characterized in that the removable mounting plate of the internal pinion bearing assembly is fixed to the housing through at least one bolt. 1

6. A differential assembly according to claim 14, characterized in that each of the internal and external pinion bearing assemblies further includes an inner bearing ring, an outer bearing ring and an outer bearing ring. bearing placed between the inner and outer bearing rings. 1

7. A differential assembly according to claim 14, characterized in that the removable support plate can be wedged through at least one wedge package placed under the removable support plate. 1

8. A differential assembly according to claim 14, characterized in that a mounting distance for the pinion head can be established through machining of the carrier in the first opening.