Description:AN IMPROVED WHEEL FOR A COMMERCIAL VEHICLE
FIELD OF INVENTION
This invention generally relates to wheels and particularly to improved wheels used with vehicles, particularly commercial vehicles. This invention relates generally to the construction of wheels, and more particularly concerns the connection of vehicle wheel bodies to wheel rims. The invention relates particularly to the engagement of rim with disc of a vehicle wheel. Particularly invention relates to the design of the wheel rim such that the wheel disc is engaged or coupled to the rim using a single set of tools for positive offset, zero offset and negative offset.
BACKGROUND OF INVENTION
A commercial vehicle wheel comprises a rim and a disc. The rim and disc are produced separately and assembled together by press fitting the disc inside the rim followed by welding rim and disc. The rim and disc can be assembled at negative offset, zero offset or positive offset. In case of zero or negative offset, the rim is fixed while disc travels and fits inside the rim by press operation. In case of positive offset, the disc is fixed while rim travels and fits outside the disc by press operation.
The existing process have following disadvantages: During press operation in zero offset, disc is travelling long length after interference of rim and disc. Thus, scratches appear on the mating surfaces of rim and disc. In order to reduce disc travel length, two separate assembly tools are required for each type of offset variant wheel e.g., one tooling for zero/negative offset and another tooling for positive offset, as fixed components and travelling components are different in both types of tooling. Separate assembly tools for separate offset variants increase the production cost of the wheel.
EP1222076B1 titled “Vehicle wheel for Goods Vehicle” This patent discloses an invention that relates to a vehicle wheel for utility vehicles, in particular for the front axle of commercial vehicles, having a wheel disc and a deep-bed rim which is connected to said wheel disc and which has an outer rim shoulder with a safety element and an inner rim shoulder, between which a rim well with a low-bed base and low-bed flanks is formed. According to the invention, it is provided that the deep-bed rim is a steep-shoulder rim, the rim shoulders of which have a shoulder inclination of approximately 15% with respect to the wheel axis, that the bottom of the deep bed extends substantially in a straight line on both sides of the center of the rim and that the outer bed flank and the inner bed flank each adjoin the rim shoulders wherein the wheel disk is welded to the bottom of the deep bed. The embodiment according to the invention leads to vehicle wheels with a wide drop-down bed, which preferably occupies more than 45% of the mouth width, in particular approximately 65% to 75% of the mouth width of the rim. The invention doesn’t disclose anything about tooling and ease of manufacture of the rim and disc assembly for the three possible offset variants, the zero, positive and negative offset.
EP0701911B1 discloses a rim profile with cylindrical transition portion (22) adjoined by a rim base (24). However, this patent does not address the problem of fitting same disc in portion 22 and in rim base 24. Also, it is not possible to fit same disc in portion 22 and in rim base 24 due to large step difference as machining of disc of this much width is not possible.
Accordingly, there exist a need for a rim and disc assembly for a vehicle wheel, wherein the same disc can be fitted at zero, negative and positive offset using the same assembly tooling such that assembly direction of disc remains same for all offset variants.
OBJECTS OF THE INVENTION
One or more problems of the conventional prior art may be overcome by various embodiments of the present invention.
It is the primary object of the present invention to provide an improved vehicle wheel wherein the rim and disc are fitted without causing any scratching on the mating surfaces.
It is another object of the present invention to provide a single tooling which could be used in the manufacture of rim and disc for all the three assemblies, the positive offset, the zero or neutral offset and the negative offset.

It is another object of the present invention to provide a rim and disc assembly for a vehicle wheel, wherein the same disc can be fitted at zero, negative and positive offset using the same assembly tooling such that assembly direction of disc remains same for all offset variants.

It is yet another aspect of the present invention to provide a rim and disc assembly for a vehicle wheel, wherein rim remains fixed while disc is travels irrespective of the type of offset, i.e. the disc travels for all the three offset variants of the rim and disc assembly.

SUMMARY OF THE INVENTION
The following disclosure presents a simplified summary of the invention in order to provide a basic understanding of some aspects of the invention. This summary is not an extensive overview of the present invention. It is not intended to identify the key/critical elements of the invention or to delineate the scope of the invention. Its sole purpose is to present some concept of the invention in a simplified form as a prelude to a more detailed description of the invention presented later.

The present invention relates to a wheel for a commercial vehicle, comprising:
a wheel rim (1) adapted to mount a tire, the rim comprising an outer flange (24) and inner flange (25);
a well portion (12), an outer bead seat portion (22), an inner bead seat portion (23), an outer curved portion (19) between outer bead seat portion (22) and well portion (12), an inner curved portion (18) between inner bead seat portion (23) and well portion (12); wherein the bottom of the well (12) on both sides of the rim center (C) comprises of a lower step (13) towards the inner curved portion (18) and an upper step on the right side of the rim center (c) towards the outer curved portion (19) and wherein the disc (15) comprises a disc engagement portion (16) which is configured to interlock with the upper step (11), lower step (13), and with the center line (C).

It is another aspect of the present invention to provide a wheel for a commercial vehicle, wherein the difference in height (W) between the upper step (11) and the lower step (13) of the well (12) is in the range of 0.8 to 3 mm.

It is another aspect of the present invention to provide a wheel for a commercial vehicle, wherein the disc engagement portion (16) with the rim is configured to interlock with the upper step (11) in a positive offset condition.

It is another aspect of the present invention to provide a wheel for a commercial vehicle, wherein the disc engagement portion (16) with the rim is configured to interlock with the lower step (13) in a negative offset condition.

It is another aspect of the present invention to provide a wheel for a commercial vehicle, wherein the disc engagement portion (16) with the rim is configured to with the center line (C) in the zero offset condition.

It is another aspect of the present invention to provide a wheel for a commercial vehicle, wherein the outer portion of the disc flange (16) is machined to engage with the center line and the lower step (13) without touching the upper step (11).

It is another aspect of the present invention to provide a wheel for a commercial vehicle, wherein outer portion of the disc flange (16) is machined to a depth of 0.8 mm to 3 mm.

BRIEF DESCRIPTION OF DRAWINGS
The advantages and features of the present invention will be more readily apparent by persons skilled in the art when considered in reference to the following description and when taken in conjunction with the accompanying drawings listed below.
Figure 1: Illustrates the contour of a prior art wheel depicting the cross section of showing zero offset of the disc engagement with the rim at the well.
Figure 2: Illustrates the engaged disc and rim assembly according to embodiments of the present invention for positive offset.
Figure 3: Illustrates the engaged disc and rim assembly according to embodiments of the present invention for zero offset.
Figure 4a: Illustrates the engaging end of the disc which is configured to interfit or interlock with the upper step in case of positive offset variant.
Figure 4b: Illustrates the engaging end of the disc which is configured to interfit or interlock with the lower step in case of positive offset variant.
Figure 4c; Illustrates the engaging end of the disc or the machined outer flange of the disc to interlock with the upper step in case of zero/negative offset variant.
Figure 5: Illustrates the interlocked disc with rim assembly in positive offset of the vehicle wheel according to a preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE DRAWINGS
The present invention as embodied by a “AN IMPROVED WHEEL FOR A COMMERCIAL VEHICLE " succinctly fulfills the above-mentioned need[s] in the art. The present invention has objective[s] arising as a result of the above-mentioned need[s], said objective[s] being enumerated below. In as much as the objective[s] of the present invention are enumerated, it will be obvious to a person skilled in the art that, the enumerated objective[s] are not exhaustive of the present invention in its entirety, and are enclosed solely for the purpose of illustration. Further, the present invention encloses within its scope and purview, any structural alternative[s] and/or any functional equivalent[s] even though, such structural alternative[s] and/or any functional equivalent[s] are not mentioned explicitly herein or elsewhere, in the present disclosure. The present invention therefore encompasses also, any improvisation[s]/modification[s] applied to the structural alternative[s]/functional alternative[s] within its scope and purview. The present invention may be embodied in other specific form[s] without departing from the essential attributes thereof.

Throughout this specification, the use of the word "comprise" and variations such as "comprises" and "comprising" may imply the inclusion of an element or elements not specifically recited.

It will be apparent to a person skilled in the art that the above description is for illustrative purposes only and should not be considered as limiting. Various modifications, additions, alterations, and improvements without deviating from the scope of the invention may be made by a person skilled in the art.
The present invention in various embodiments discloses a vehicle wheel for commercial vehicle wheel (100), comprising: a wheel rim (10) adapted to mount on a tire, the rim comprising and outer flange (24) and an inner flange (25). The centre of the rim comprises a well portion (12). The well (12) is the base of the rim (10), as illustrated in Figures 2 and Figure 5. A bead seat portion of rim comprising of an outer curved portion (19) towards the outer side and an inner curved portion (18) towards the inner side connected to the well (12). The width of the well for representative purposes is represented in figure 3 as “d”. The rim further comprises an outer bead seat portion (22) and an inner bead seat portion (23).
Rim center (C) is the central median of the rim. The distance between the centerline of the rim and the hub mounting surface of the wheel is called the "offset" and can be positive, negative, or zero.

The bottom of the well (12) on both sides of the rim center (C) comprises of a lower step (13) towards the inner flank (18) and an upper step on the right side of the rim center (C) towards the outer flank and wherein the disc (15) comprises a disc engagement portion (16) which is configured to interlock with the upper step (11), lower step (13), and with the center line (C).

In prior art (reference to figure 1a) the rim is the traveling part and the disc is the stationary part during negative/zero offset. While in positive offset (reference to figure 1b), the disc is the traveling part and the rim is the stationary part. In the present invention, in one embodiment the fixed part is the rim (10) and the disc is the traveling part (The direction of travel is represented in Figures 2 and 3 as D from Right to Left). In both figures 2 and 3 represent the embodiments of the present invention for positive and zero offset respectively. The well in the prior art or the contemporary, rims there is a single straight line at the base or the well between the inner and outer bed flanks. As discussed in the background section, this causes scratching on the mating surfaces of the rim with the disc in case of negative offset where the disc is made to travel the entire length of the well base (12). The novelty of the invention lies in the bifurcation of the rim well (12), into two halves, the half on the right hand side of the wheel towards outside of the wheel, is higher in the height i.e. it forms an upper step (11), whereas the half on the left hand side of the wheel towards the insider is lowered, in comparison to the straight line “d” between the inner flank (18) and the outer flank (19).

The vehicle wheel according to an embodiment of the present invention is configured such that the rim comprises of an outer flange (24) towards the Right indicated by “R” in Figure 2 and Figure 3. From the outer flange (24) the rim is designed to include bead seat portion (22), followed by a hump (20) and followed by the outer curved portion (19). The similar description on the Left side marked as “L” in Figure 3, comprises on the hub side or the inner side.

In the prior art, hitherto, in zero and positive offset variant, it was required to have different set of tools for machining, to avoid both the scratching and to enable the disc to reduce the distance of travel. There are two assemblies for die and punch for the rim and the disc assembly manufacture. Present invention overcame this major drawback by providing a “stepped rim design”. A single tool of the die and punch, is developed which for positive offset, rim remains fixed or stationary and the disc travels. In reference to Figure 2, the disc engagement portion 16 engages with the upper step (11) for providing a rim and disc assembly of positive offset. The upper step and the lower step are at a height difference of W which is equal to 0.8 to 3 mm, preferably 1-3 mm.

In one embodiment the same tooling of die and punch are used in zero and negative offset, the disc engagement portion (16) as illustrated in figure 4b, is moved towards the rim center (c). In reference to the figure 3, in order to fix the disc to the rim in case of zero and negative offset, the outer portion of the disc flange is machined so that it will engage with the center line and the lower step (13) without touching the upper step (11). Figure 4b, illustrates machining the outer flange portion of disc (W1) in order to get it engaged with lower step (13). The machining range – 0. 8 mm to 3 mm, preferably 1-3 mm.

Advantages:
1. Prevents scratching on rim and disc mating surfaces during assembly.
2. Disc travels shorter distance during assembly for all offset variants.
3. Same disc can be used to fit in upper step as well as in lower step by adding one machining operation.
4. Use of same assembly tooling for different offset variants.
5. Standardized manufacturing process for all similar wheel sizes having different offset variants.
6. Reduced production cost
7. Overall product cost also gets reduced.
, Claims:WE CLAIM:
1. A wheel for a commercial vehicle, comprising:
a wheel rim (1) adapted to mount a tire, the rim comprising an outer flange (24) and inner flange (25);
a well portion (12), an outer bead seat portion (22), an inner bead seat portion (23), an outer curved portion (19) between outer bead seat portion (22) and well portion (12), an inner curved portion (18) between inner bead seat portion (23) and well portion (12);
characterized in that the bottom of the well (12) on both sides of the rim center (C) comprises of a lower step (13) towards the inner curved portion (18) and an upper step on the right side of the rim center (c) towards the outer curved portion (19) and wherein the disc (15) comprises a disc flange (16), outer part of which is configured to interlock with the upper step (11), lower step (13), and with the center line (C).

2. The wheel for a commercial vehicle as claimed in claim 1, wherein the difference in height (W) between the upper step (11) and the lower step (13) of the well (12) is in the range of 0.8 to 3 mm.
3. The wheel for a commercial vehicle as claimed in claim 1, wherein the disc engagement portion (16) with the rim is configured to interlock with the upper step (11) in a positive offset condition.

4. The wheel for a commercial vehicle as claimed in claim 1, wherein the disc engagement portion (16) with the rim is configured to interlock with the lower step (13) in a negative offset condition.

5. The wheel for a commercial vehicle as claimed in claim 1, wherein the disc engagement portion (16) with the rim is configured to with the center line (C) in the zero offset condition.

6. The wheel for a commercial vehicle as claimed in claim 1, wherein the outer portion of the disc flange (16) is machined to engage with the center line and the lower step (13) without touching the upper step (11).

7. The wheel for a commercial vehicle as claimed in claim 1, wherein the outer portion of the disc flange (16) is machined to a depth of 0.8 mm to 3 mm.