TECHNICAL FIELD

The subject matter described herein, in general, relates to a wheel axle assembly, and in particular relates to a wheel axle assembly for vehicles.

BACKGROUND

Rotating or moving components of a vehicle or a machinery, for example, brakes, clutches, gears, shafts, etc., need protection from external hazards and corrosives such as water, dirt, mud, etc. To provide protection from such hazards and corrosives, these components are enclosed in their housings. These housings are generally manufactured as multiple pieces and then are assembled together by fastening means such as nuts and bolts. Further, the spaces and gaps between the pieces of housings are sealed using various seals, such as oil seals and mud seals, to bar the entry of foreign particles and to prevent leakage of oil from the housings.

A wheel axle assembly is an important part of a vehicle having rotating components, which need due protection. The wheel axle assembly includes an axle shaft housed in an axle housing, a brake assembly housed in a brake housing, and wheel hub, on which one or more wheels are mounted. The axle housing and the brake housing are fastened together using fastening means such as washers, nuts, and bolts.

A typical wheel axle assembly 100 for a vehicle, such as a tractor, is shown in Fig. 1. The wheel axle assembly 100 includes a brake housing 102 closed at one end by an end cover 104. The brake housing 102 encloses and protects a brake assembly 106. The brake housing 102 is fastened to an axle housing 108 through fastening means such as nuts and bolts. The axle housing 108 houses an axle shaft 110. The brake assembly 106 is mounted on the axle shaft 110 via a hub adaptor 112. The engagement and disengagement of the brake assembly 106 is controlled by cam mounted on a brake cam shaft 114, which in turn is mounted on a cam shaft bracket 116.

The end cover 104 is also mounted on the axle shaft 110 through an arrangement that includes a threaded sleeve 118, a ball bearing 120, and a circle 122 such that the axle shaft 110 can rotate while the end cover 104 remain stationary. An oil seal 124 is provided between the end cover 104 and the axle shaft 110 to prevent grease, water, etc., from entering into the brake housing 102. The axle shaft 110 is connected to one or more wheels through multiple wheel bolts 126-1, 126-n, mounted on a wheel hub 127 integrated with one end of the axle shaft 110. Towards a wheel-end of the axle shaft 110, a mud block seal 128 is provided to prevent entry of mud and dirt into the brake housing 102. A lower link bracket 130 is also provided at a lower end of the axle housing 108 for mounting a lower link of a three point linkage (not shown in Fig 1).

The brake assembly 106 has two braking members such that one braking member is rotating while other braking member is stationary. When brake assembly 106 is engaged, the rotating braking member comes in contact of the stationary member. As a result, due to friction between the two braking members enormous heat is generated. The heat generated, during engagement of the breaking members, is dissipated to the ambience through the brake housing 102 and end cover 104. The heat dissipation depends upon the area of the brake housing and end cover 104. The limited area of the brake housing 102 and end cover 104 poses a limitation to the heat dissipation. Consequently improper heat dissipation often leads to substantial wear and tear of the braking members of the brake assembly 106.

Moreover, the wheel axle assembly 100 has multiple components that are fitted together and therefore have multiple joints, mud or environmental particulates may enter the wheel axle assembly 100 through the these joints, reducing the life of the wheel axle assembly 100.

SUMMARY

The subject matter described herein is directed to a wheel axle assembly for use in vehicles, particularly, heavy vehicles such as tractors and trucks. In one embodiment, the wheel axle assembly includes an axle shaft, a brake assembly, and an integrated housing. The integrated housing houses both the brake assembly and the axle shaft. The brake assembly is located at a wheel end of the axle shaft, close to the wheels, which increases the braking efficiency of the brake assembly. In addition, the integrated housing facilitates better heat dissipation through a larger area of the integrated housing, thereby increasing the life of the brake assembly.

These and other features, aspects, and advantages of the present subject matter will be better understood with reference to the following description and appended claims. This summary is provided to introduce a selection of concepts in a simplified form. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features, aspects, and advantages of the subject matter will be better understood with regard to the following description, appended claims, and accompanying drawings where:

Fig. 1 illustrates a cross sectional view of a typical wheel axle assembly known in the art.

Fig. 2 illustrates a cross sectional view of an exemplary wheel axle assembly, according to an embodiment of the present subject matter.

Fig. 3 illustrates a sectional view, along a line AA', of an integrated housing as shown in
Fig. 2 according to an embodiment of the present subject matter.

Fig. 4 illustrates an expanded view of a wheel end of the wheel axle assembly of Fig. 2 according to an embodiment of the present subject matter.

Fig. 5 illustrates an exemplary arrangement for mounting an end cover on an axle shaft of the wheel axle assembly of Fig. 2 according to an embodiment of the present subject matter.

DETAILED DESCRIPTION

The subject matter described herein is directed to a wheel axle assembly for heavy vehicles such as trucks and tractors. In one embodiment, the wheel axle assembly described herein includes an integrated housing, an axle shaft, and a brake assembly. The integrated housing houses both the axle shaft and the brake assembly. The brake assembly has two braking members such that one braking member is rotating while other is stationary. The stationary braking member of the brake assembly is mounted on the integrated housing, thus eliminating the requirement for a separate brake housing. The brake assembly is located at a wheel end of the axle shaft. Moreover, the wheel axle assembly has provisions for sealing and protection of the brake assembly and the axle shaft from mud, dirt, etc.

Fig. 2 illustrates a cross sectional view of a wheel axle assembly 200 according to one embodiment of the subject matter. The wheel axle assembly 200 includes an axle shaft 202, an integrated housing 204, and a brake assembly 206. In one embodiment, the axle shaft 202 is a direct drive axle, i.e., that the axle shaft 202 is a single shaft connecting a crown wheel differential arrangement (not shown in Fig 2) to the wheels of the vehicle, in particular to the rear wheels. The axle shaft 202 is housed in the integrated housing 204. Further, the integrated housing 204 also houses the brake assembly 206. The brake assembly 206 has a stationary braking member 207 and a rotating braking member 208, wherein the stationary braking member 207 of the brake assembly 206 is housed in the integrated housing 204. The brake assembly 206 is mounted on the axle shaft 202 via a hub adaptor 209. The integrated housing 204 is deployed effectively when the brake assembly 206 is a dry disc brake assembly. The concept of integrated housing 204 can also be extended to a wet disc brake assembly.

The brake assembly 206 is actuated by a cam 210 mounted on a cam shaft 211, which is in turn operated by a brake lever 213. Thus, the movement of the brake lever 213 governs the engagement and disengagement of the braking members of the brake assembly 206. The cam shaft 211 can be positioned in multiple bores 212 provided in the integrated housing 204. Although, the operation of the brake assembly 206 is illustrated using a cam shaft arrangement, it will be understood that the brake assembly 206 can also be operated by other arrangements too, for example, a pull rod system or any other mechanical or hydraulic actuating mechanism.

The integrated housing 204 is closed by an end cover 214 at a wheel end, where wheels are mounted. The end cover 214 is mounted using a rolling element bearing 216 on the axle shaft 202.

Fig. 2 shows only half of the wheel axle assembly 200; however, the other half (not shown in the Fig 2) is symmetrical to the half shown. Line 218 represents the line of symmetry. Thus, it is appreciated to understand that the each of the two ends of the axle shaft 202 has a wheel hub 220 attached to it. As mentioned earlier, the integrated housing 204 houses the brake assembly 206 along with the axle shaft 202 and the hub adaptor 209. Thus, the requirement of separate brake housing 102 and axle housing 108 has been eliminated, thereby reducing the number of members that need to be assembled within the wheel axle assembly 200. The integrated housing 204 facilitates better cooling of the brake assembly 206, because, due to integration more area is available for heat dissipation. Improvement in cooling, due to better heat dissipation, enhances the life of the brake assembly 206.

In addition, the deployment of the integrated housing 204 significantly reduces the number of joints in the wheel axle assembly 200 as a result of reduction in the number of members of the wheel axle assembly 200. Thus, the integrated housing 204 is more effective in preventing entry of water, mud, etc., into the integrated housing 204, especially when the vehicle is used in field applications.

Further, as the brake assembly 206 is located at the wheel end of 400 (shown in Fig.4) the wheel axle assembly 200, the rotating braking member 207 rotate at a low speed due to reduction of speed in the crown differential. The rotation of the rotating braking member 207 of the brake assembly 206 at a low speed avoids glazing of the brake liners, provided in the braking members 207 and 208 of the brake assembly 206, thus improving the life of the brake assembly 206. The structural details of the wheel axle assembly 200 are described in further detail in Fig. 3.

Fig. 3 illustrates a sectional view 300, along a line AA', of the integrated housing 204 as shown in Fig. 2. The integrated housing 204 has a provision to mount a three point linkage (not shown in the Fig. 3). The integrated housing 204 has a lug 302 having a bore 303 through which a pin 304 can pass. The pin 304 can be used to attach a lower link of the three point linkage to the integrated housing 204. The pin 304, when inserted in the bore 303 provided in integrated housing 204, is locked by a grub screw (not shown in Fig 3).

Fig. 4 illustrates an expanded view of components arranged towards the wheel end 400 of the wheel axle assembly 200 in Fig. 2. In order to provide proper sealing and protection to the components of the wheel axle assembly 200, various seals are provided in the wheel axle assembly 200. For example, a mud block seal 402 is used towards the wheel end 400 to prevent the rolling element bearing 216 and the brake assembly 206 from mud and water seepage during field operations. Further, an oil seal 404 and a sleeve oil seal 406 are used to isolate the brake assembly 206 from external environment. Thus, the rotating components of the wheel axle assembly 200 get protected from external hazards and corrosives by the use of mud block seal 402 and oil seals 404 and 406 during the general field operations or any heavy duty, wet land operations. Moreover, the integration of the brake housing 102 and the axle housing 108 significantly reduces the number of joints with respect to a typical wheel axle assembly 100 as shown in Fig. 1, hence, minimizing the entry of water and mud into the wheel axle assembly 200.

Further, a shroud end cover 408 is used to cover a portion of the wheel axle assembly 200 lying between the wheel hub 220 and the end cover 214. The shroud end cover 408 is coupled to a felt seal 410 to further protect components within.

Towards the wheel end 400 of the wheel axle assembly, multiple wheel bolts, such as wheel bolts 412-1, 412-2...... 412-n, collectively referred to as wheel bolts 412 hereinafter, are provided to attach wheels to the axle shaft 202. The wheel bolts 412 are fastened to the wheel hub 220. The placement of the shroud end cover 408 is such that that the wheel bolts 412 can be removed and assembled without dismantling the wheel axle assembly 200 from the vehicle. For this, only the shroud end cover 408 needs to be removed. Thus, the wheel axle assembly 200 provides improved serviceability.

Fig. 5 illustrates an exemplary arrangement 500 for mounting the end cover 214 on the axle shaft 202 of the wheel axle assembly 200. The end cover 214 is mounted on the axle shaft 202 using the rolling element bearing 216 and a spacer-circlip arrangement. The spacer-circlip arrangement includes a spacer 502 and a first circlip 504 and a second 506. The first and the second circlips 504 and 506 are provided to restrict the axial movement of the rolling element bearing 216. The first circlip 504 is an external circlip and is placed in a groove on the axle shaft 202, while the second circlip 206 is an internal circlip and is located in a groove in the end cover 214. The spacer 502 is provided between the rolling element bearing 216 and the circlip 504 to place the first circlip 504 on the axle shaft 202. Such a spacer-circlip arrangement makes the whole arrangement more user friendly and serviceable as the end cover 214 can be easily removed to access the axle shaft 202.

The aforementioned versions of the subject matter and equivalent thereof have many advantages, including those which are described above.

The relative location of the brake assembly 206 near the wheel end 400 of the integrated housing 206 makes the overall drive line more efficient for the transmission of drive torque from engine to the wheels of the vehicle. Also, braking is more efficient and servicing or replacement of the braking members 207 and 208 is comparatively easy. Improved heat dissipation from the brake assembly 206 increases the life of the wheel axle assembly 200 as a whole.

The integrated housing 204 is manufactured as a single entity. Thus, the integration of brake housing 102 and axle housing 108 reduces the number of joints in the wheel axle assembly 200 and thereby entry of corrosives is effectively prevented. The integrated housing 204 also facilitates better load distribution, thereby improving the load bearing capacity of the wheel axle assembly 200.

Although the subject matter has been described in considerable detail with reference to certain preferred embodiments thereof, other embodiments are possible. As such, the spirit and scope of the appended claims should not be limited to the description of the preferred embodiment contained therein.

I/We claim:

1. A wheel axle assembly (200) comprising:

an axle shaft (202);

a brake assembly (206) operationally mounted at a wheel end (400) of said axle shaft (202);

characterized in that,

said axle shaft (202) and said brake assembly (206) are housed in an integrated housing (204).

2. The wheel axle assembly (200) as claimed in claim 1, wherein said wheel axle assembly (200) further comprises a cam (210) mounted on a cam shaft (211) positioned in a plurality of bores (212) provided in said integrated housing (204), and wherein said brake assembly (206) is operated by said cam (210).

3. The wheel axle assembly (200) as claimed in claim 1, wherein said integrated housing (204) comprises a lug (302) having a bore (303) for mounting a pin (304).

4. The wheel axle assembly (200) as claimed in claim 3, wherein said pin (304) attaches a three point linkage to said integrated housing (204).

5. The wheel axle assembly (200) as claimed in claim 1, wherein said brake assembly (206) comprises a stationary braking member (207) housed in said integrated housing (204), and wherein said integrated housing (204) facilitates enhanced dissipation of heat produced during the operation of brake assembly (206).

6. The wheel axle assembly (200) as claimed in claim 1, wherein the wheel axle assembly (200) is a direct drive axle assembly.

7. A heavy vehicle comprising said wheel axle assembly (200), as claimed in any of the preceding claims.

8. A tractor comprising said wheel axle assembly (200), as claimed in one of the claims 1 to 6.