Axle assembly for drive device of a motor vehicle

Abstract

An axle assembly for a drive device for the road wheels of a vehicle includes: a stationary housing having a housing interior at least partially filled with a lubricating liquid; axle housings connected to the stationary housing and configured to permit axles of the vehicle to pass towards the road wheels; a venting bore in one of the axle housings configured to allow pressurized air to escape from the stationary housing; and at least one rib sized and positioned in the housing interior of the stationary housing so as to prevent migration of the lubricating liquid out of the venting bore.

Claims

1. An axle assembly (1) for a drive device for road wheels (7) of a vehicle, comprising: a stationary housing (10) having a housing interior (9) at least partially filled with a lubricating liquid; differential supports (23) arranged in the housing interior (9), the differential supports contactingly supporting a differential of the drive device; axle housings (20) connected to and extending from the stationary housing (10) and structured and arranged with respect to the stationary housing (10) so as to provide respective openings through which the axles (5) of the vehicle pass towards the road wheels (7); a venting bore (22) in one of the axle housings (20) configured to allow pressurized air to escape from the stationary housing (10); and at least two ribs (34) arranged, parallel or substantially parallel to each other, at an upper surface of said housing interior (9) of said stationary housing (10) and positioned transverse to a direction of the one of the axle housings (20) having the venting bore (22), said at least two ribs (34) being arranged in a region of the housing interior (9) at which the stationary housing (10) joins the one of the axle housings (20) having the venting bore (22) so as to prevent migration of the lubricating liquid out of the venting bore (22), at least one of the at least two ribs (34) being arranged in the housing interior (9) so as to extend from one of the differential supports (23) to an opposing wall of the stationary housing (10).

2. The axle assembly (1) according to claim 1, wherein each of said at least two ribs (34) comprises a wall portion projecting radially inwardly in relation to the housing interior (9) and configured to intercept lubricating liquid in said stationary housing (10).

3. The axle assembly (1) according to claim 1, wherein said at least two ribs (34) are formed integrally with said stationary housing (10).

4. The axle assembly (1) according to claim 1, wherein said at least two ribs (34) are fastened to said housing interior (9) of said stationary housing (10).

5. The axle assembly (1) according to claim 1, wherein said at least two ribs (34) are arranged substantially parallel with a drive shaft of the drive device and perpendicular to an axis of rotation of the axles (5).

6. The axle assembly (1) according to claim 1, wherein the number of the at least two ribs (34) equals two.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) An embodiment of the present invention is described more fully in the following description and is shown in the accompanying drawing in which:

(2) FIG. 1 is a schematic view of a prior art drive shaft and rear axle assembly;

(3) FIG. 2 is a sectional view of a prior art axle assembly having a stationary housing without showing the drive shaft or the differential unit;

(4) FIG. 3 is a sectional view of an axle assembly having a stationary housing according to an embodiment of the present invention;

(5) FIG. 4 is a sectional view of an axle assembly having a stationary housing according to an embodiment of the present invention without showing the drive shaft or the differential unit; and

(6) FIG. 5 is a side sectional view of the stationary housing shown in FIGS. 3 and 4.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

(7) The reference numerals from FIGS. 1 and 2 will be maintained in the following drawings except where the disclosed embodiments differ.

(8) FIGS. 3-5 are views of the axle assembly 1 according to an embodiment of the present invention having a stationary housing 10 and axle housing 20.

(9) FIG. 3 is a sectional view showing the stationary housing 10 according to the present invention with a differential unit 16 installed within the stationary housing 10. As discussed above, a driveshaft 3 (not visible in this view), which is rotatably drivable by an engine of a vehicle, is guided into the interior 9 of the stationary housing 10 approximately horizontally.

(10) At its end, the driveshaft 3 carries a driving gear wheel 12, visible in FIG. 3 behind the components of the differential unit 16. The driving gear wheel 12 is formed as, for example, a bevel gear configured to mesh with a crown wheel 14 of the differential unit 16. The crown wheel 14 is likewise formed as a bevel gear.

(11) A differential housing 26 is fixedly connected to the crown wheel 14 and is bearing-mounted at two differential bearings 28, 30 so as to be rotatable around an axis of rotation 8, illustrated in FIG. 1, extending at right angles to the axis of rotation of the driveshaft 3.

(12) The first differential bearing 28 is connected to the stationary housing 10, typically by a screw connection (not shown). The second differential bearing 30 is supported by the bearing bracket 31.

(13) Driven gear wheels 32 are formed as bevel gears and are fixedly arranged on driven shafts 5 which extend opposed to one another through the axle housings 20 to drive the road wheels 7 of a vehicle. The bevel gears of the driven gear wheels 32 are bearing-mounted at the differential housing 26 so as to be freely rotatable. A plurality of differential gear wheels 27 are rotatably drivable by the crown wheel 5, the driven gear wheels 32 being rotatably drivable by the differential gear wheels 27.

(14) The interior 9 of the housing 10, including the above-mentioned axle bracket 24, are partially filled with a lubricating liquid, e.g., oil. Ribs 34, which will be discussed in greater detail below, can be seen at the upper right of FIG. 3 projecting from the interior of the stationary housing 10 in the area of the axle bracket 24. The venting bore 22 is visible at the upper right of FIG. 3 in one of the axle housings 20.

(15) FIGS. 4 and 5 illustrate the axle assembly 1, including the stationary housing 10 and axle housings 20, in accordance with an embodiment of the present invention. For ease of viewing the interior of the stationary housing 10 and the ribs 34, the stationary housing 10 is shown in FIGS. 4 and 5 without the differential unit 16 installed.

(16) As can be seen from FIGS. 4 and 5, the stationary housing 10 communicates with axle housings 20, through which the axles 5 pass towards the wheels 7. A venting bore 22, which allows pressurized air to escape upon excessive buildup of such air, is located in one of the axle housings 20. Differential supports 23 are formed in the interior of the stationary housing 10 and provide support for the differential unit 16. An oblique upper wall of the interior 9 of the stationary housing 10 forms an axle bracket 24 in the area of the stationary housing 20 close to where the axle housing 20 joins the stationary housing 10.

(17) In accordance with a particularly advantageous aspect of the disclosed embodiment of the present invention, two ribs 34 are arranged, substantially parallel to one another, in the interior 9 of the stationary housing 10 at the axle bracket 24. As discussed above, in prior art stationary housings, the splashing of lubricating liquid by the moving components of the differential unit 16, and the driveshaft gear 12, causes lubricating liquid to travel along the interior walls at the axle bracket 24 in such a way that the lubricating liquid escapes from the venting bore 22. The ribs 34 of the present invention prevent this from happening. FIG. 5 shows the arrangement of the ribs 34 in a side view, looking down the axle housing 20.

(18) While two ribs 34 are shown in the illustrated embodiment, the number of ribs is not limited to two. More than two ribs can be utilized, and even providing a single rib 34 provides the advantageous effect of the present invention.

(19) As shown in FIGS. 4 and 5, each of the ribs 34 is arranged transversely, across the top of interior 9 of the stationary housing in the area of the axle bracket 24. In particular, each of the ribs 34 is arranged to extend in a direction substantially perpendicular to the axis of rotation 8 of the axles 5, and substantially parallel to the direction of the drive shaft 3.

(20) Each rib has a radial width dimension, extending from the top of the axle bracket 24 and downwardly into the interior 9 of the stationary housing 10. This radial width dimension is provided so as to be sufficient to intercept lubricating liquid that is splashed from the moving components housing in the stationary housing, but without contacting any moving parts of the differential unit 16. This orientation of the ribs, with a projecting radial width, allows the walls of the ribs 34 that face the differential unit 16 to intercept the splashed lubricating liquid, preventing the lubricating liquid from migrating towards the venting bore 22. The dimensions of the longitudinal extent and axial extent of the ribs will vary depending on the size of the stationary housing 10 in which they are arranged and the components arranged within the stationary housing 10 and can easily be determined by a person of skill in the art.

(21) By virtue of the operation of the ribs 34, rather than migrate toward the venting bore 22, splashed lubricating liquid is intercepted and collects on the inner wall faces of the ribs 34. Advantageously, any lubricating liquid that collects on the inner wall surfaces of the ribs 34 in this manner will simply, by the force of gravity, drip back down into the stationary housing 10, so that substantially the same amount of lubricating liquid remains available for lubricating the moving parts of the differential unit 16.

(22) Preferably, the ribs 34 are formed integrally in the same casting process that forms the stationary housing 10, which is preferably made of cast iron, or other appropriate metal or alloy. However, the invention is not limited to the ribs 34 being formed integrally. The ribs 34 may instead, for example, be of a different material, such as a plastic, and be bolted, glued, or otherwise affixed, to the wall of the stationary housing in the location shown in the figures.

(23) Thus, while there have been shown and described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements and/or method steps shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.