WO2009029990A1

WO2009029990A1 - Wheel assembly

Info

Publication number: WO2009029990A1
Application number: PCT/AU2008/001318
Authority: WO
Inventors: Brett Guy Fennell
Original assignee: Brett Guy Fennell
Priority date: 2007-09-04
Filing date: 2008-09-04
Publication date: 2009-03-12

Abstract

There is provided a wheel assembly (10) comprising a rim base (12) arranged for receiving a tyre. The assembly further comprises a mounting portion (40) configured to couple the rim base (12) to a vehicle axle and a damping assembly in operative communication between the inner circumferential surface (16) and the mounting portion (40).

Description

WHEEL ASSEMBLY

Field of the Invention

The present invention relates to a wheel assembly. In particular, although not solely, the present invention relates to a solid tyre wheel assembly for use with heavy vehicles such as construction and mining equipment .

Background of the Invention

Pneumatic tyres are widely used on land vehicles, including heavy vehicles used in the construction and mining industries. Where land vehicles are operated on over rough terrain, such as for example in off-road or underground operations, tyre tread utilization is frequently 40-70% of the estimated tyre tread lifetime due to tyre blow-outs and irreparable damage to the tyre sustained under normal but harsh operational conditions. Further, maintenance to pneumatic tyres to repair punctures, monitor and adjust tyre pressure, and to conduct testing on the pneumatic tyre rims is time consuming, and therefore costly to operations, particularly when it leads to downtime of the vehicle.

Solid tyres demonstrate several advantages over pneumatic tyres in that they are not subject to punctures and therefore generally have a greater tyre tread lifetime and have an increased operational availability in comparison to pneumatic tyres. Additionally, as the use of a solid tyre is not reliant on monitoring and maintaining air pressure in the tyre, there are reduced maintenance requirements for both the solid tyre and its corresponding tyre rim in comparison to a pneumatic tyre wheel assembly. Generally, less material is used in the fabrication of low profile solid tyres, thus making them lighter than, for instance, a normal 100 series tyre. Additionally, low profile solid tyres disperse heat more efficiently than 100 series solid tyres, therefore avoiding heat deterioration and tyre failure. However, the acknowledged disadvantages of using low profile solid tyres include decreased driver comfort due to little or no cushioning effect normally experienced with pneumatic tyres, and overall reduced performance in the operation of construction and mining equipment which rely, at least in part, on the resilience of the tyres to provide momentum in certain operations.

The present invention seeks to overcome at least some of the above mentioned disadvantages.

Summary of the Invention

In its broadest aspect, the invention provides a wheel assembly.

Accordingly, in a first aspect of the invention there is provided a wheel assembly comprising: a rim base arranged for receiving a tyre; a mounting portion connectable to a vehicle axle; and, a damping assembly in operative communication between the rim base and the mounting portion.

In one embodiment of the invention, the damping assembly comprises one or more resilient members embedded in the mounting portion in an arrangement whereby the one or more resilient members deform in response to a load applied to the rim base .

In another embodiment the mounting portion comprises a nave plate concentrically supported on the rim base, the nave plate having a plurality of apertures therein, the apertures being configured to receive the one or more resilient members.

In a further embodiment of the invention, the wheel assembly is provided with a pair of nave plates as described above spaced apart from one another. The nave plates are substantially equidistantly spaced from side edges of the rim base .

In one embodiment of the invention, the resilient member comprises an annulus formed from resilient material. The annulus. may be provided .with an outer circumferential sleeve and an inner circumferential sleeve. In some embodiments of the invention, the inner circumferential sleeve has a greater length than the annulus.

Notwithstanding that the annulus is formed from resilient material and contracts under load, opposing side walls of the annulus tend to bulge when a load is applied to the annulus. Accordingly in one embodiment, opposing side walls of the annulus are substantially concave.

In another embodiment of the invention, the apertures are equiangularly disposed within the nave plate proximal to the inner circumferential surface of the rim base. In a preferred embodiment, the nave plate has a plurality of substantially sinusoidal lobes radially extending relative to a central rotational axis of the wheel assembly in an arrangement whereby each lobe accommodates one respective aperture therein.

In one embodiment the apertures are cylindricalIy shaped. In one form respective resilient members can be press- fitted into the cylindrically shaped apertures. In one embodiment of the invention, the wheel assembly further comprises a mounting ring supported by a respective wheel hub, wherein the mounting ring is arranged in use to be fastened to the respective nave plate by a plurality of fastening devices transversely extending through respective resilient members. Each fastening device is configured to be received in a space defined by the inner circumferential sleeve of the respective annulus of resilient material.

In one embodiment the mounting ring can have a concentric flange inwardly, the concentric flange being arranged, in use, to . be mounted in close facing arrangement on the wheel hub .

In another embodiment the mounting ring can have two concentric flanges outwardly depending on the mounting ring so as to define a channel therebetween. In one form of this, the channel is configured to receive the nave plate therein.

In one embodiment, the nave plate is engaged in the channel by facilitating relative lateral translation between the nave plate and the mounting ring. In a further embodiment, when the nave plate is received in the channel, relative rotation between the mounting ring and the nave plate facilitates lateral alignment of the fastening devices with reciprocal apertures in the flanges, the reciprocal apertures being configured to receive the fastening devices and thereby fasten the mounting ring to the nave plate in a close facing arrangement .

In one embodiment the flanges and the nave plate have complementary shaped surfaces with respect to one another to facilitate relative lateral translation between the flange depending from the inner circumferential side of the mounting ring and the nave plate. In one form, the flanges have a plurality of substantially sinusoidal lobes radially extending relative to a central rotational axis of the solid tyre wheel assembly in an arrangement whereby each lobe accommodates one reciprocal aperture therein.

Brief Description of the Drawings

Embodiments of the present invention will now the described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 shows a perspective view of a wheel assembly according ^"to one embodiment of the present invention;

Figure 2 shows a cross sectional view of the wheel assembly of Figure 1;

Figure 3 shows a perspective view of a nave plate comprised in the wheel assembly of Figures 1 and 2 ;

Figure 4 shows a perspective view of a resilient member comprised in the wheel assembly of Figures 1 and 2 ; Figure 5 shows a perspective view of a mounting ring comprised in the wheel assembly of Figures 1 and 2 ;

Figure 6 shows a perspective view of the nave plate and mounting ring of Figures 4 and 5, respectively, in which a first relative alignment of complementary surfaces of the nave plate and the mounting ring to facilitate lateral translation of the mounting ring relative to the nave plate is illustrated;

Figure 7 shows a perspective view of the nave plate and mounting ring of Figures 4 and 5, respectively, in which a second relative alignment of the nave plate and the mounting ring to facilitate lateral alignment of fastening devices extending between the mounting ring and the nave plate is illustrated; and,

Figure 8 shows a sectional view of a detail of the portion of the embodiment of Figure 2 that is shown in the circle A of solid outline. Detailed Description of Embodiments of the Invention

Referring to the Figures, where like numerals refer to like features throughout, a wheel assembly 10 is shown. Although embodiments will be described with reference to solid tyres, it will be appreciated by those skilled in the art that a pneumatic tyre may also be utilised with embodiments of the wheel assembly in accordance with the present invention.

The assembly 10 includes a solid tyre rim base 12 having an outer circumferential surface 14 for supporting a solid tyre (not. shown) thereon and an inner circumferential surface 16. According to one embodiment of the present invention, the solid tyre is a low profile solid tyre. Although the solid tyre rim base 12 is of conventional design, it will be appreciated that the diameter of the solid tyre rim base 12 is greater than the diameter of a pneumatic tyre rim base for a wheel of similar size to account for the use of the low profile solid tyre. The term "low profile" as used herein refers to a tyre whose side wall height is less than its width. Typically, a rim diameter of the solid tyre rim base 12 varies from 25" to 63" .

As shown in Figures 1 and 2, the wheel assembly 10 also includes a pair of nave plates 20 spaced apart from one another and concentrically supported on the inner circumferential surface 16 of the solid tyre rim base 12. The nave plates 20 are substantially equidistantly spaced from side edges of the solid tyre rim base 12 so that the assembly 10 can be rotated so the offset is the same. Typically, one or both sides of the nave plate 20 adjacent its outer circumferential surface 22 are welded to an inner surface 16 of the solid tyre rim base 12. The nave plate 20 is generally ring shaped and has a plurality of equally spaced axially extending apertures 24. As shown in detail in Figure 3, the nave plate 20 has a plurality of substantially sinusoidal lobes 26 that extend radially inward relative to a central rotational axis A of the solid tyre wheel assembly 10. The lobes 26 defining an inner surface 28 of the nave plate 20. Each lobe 26 accommodates one respective aperture 24 therein.

In this particular embodiment, the apertures 24 are cylindrical, and have been machined to an appropriate size to receive a respective resilient member 30, one of which is shown in- more detail in Figure 4.

The resilient member 30 comprises an annulus 32 formed from a resilient material. Illustrative examples of suitable resilient materials include natural rubber such as for example 20-60 Duro rubber, synthetic rubber, silicone, and elastomeric plastic materials as are well known to those skilled in the art.

In the preferred embodiment, the annulus 32 has an outer circumferential sleeve 34 and an inner circumferential sleeve 36 which more readily facilitates press-fitting of the resilient member 30 into its respective aperture 24 in the nave plate 20. Typically, the outer and inner circumferential sleeves 34, 36 are formed from mild steel.

The inner circumferential sleeve 36 is configured to receive a fastening device 38 therein. In some embodiments of the invention, the inner circumferential sleeve 36 has a greater depth than the annulus 32 for reasons as will be described later.

When the annulus 32 of resilient material is placed under load, it deforms and the annulus 32 shortens in diameter in at least one direction substantially aligned with the applied load. Notwithstanding the contraction of the resilient material, side walls 37 of the annulus 32 will tend to bulge when the annulus 32 is placed under load. As will be understood from Figure 8, in use the resilient member 30 is located in a confined space. Thus to anticipate the "bulging" of the side walls 37 of the annulus 32 when placed under load in the confined space, it is preferable that the side walls 37 of the annulus 32 are substantially concave when not under load.

The wheel assembly 10 comprises a mounting portion, in this example a mounting ring 40, configured to engage and be fastened to respective nave plates 20 by the fastening devices 38 ^• transversely extending through respective resilient members 30 as shown in Figures 1, 2, and 7. It will be appreciated that, in this arrangement, when a load is applied to the solid tyre rim base 12 of the assembly 10, the resilient members 30 embedded in the nave plate 20 will deform in response to the load and there will be a translational displacement of the nave plate 20 commensurate with the deformation in each of the resilient members 30 relative to the mounting ring 40. It is in this way that a "damping effect" is provided to the wheel assembly 10. In some embodiments, a translational displacement of about 5-30 mm is desirable.

A further embodiment of the mounting disk 40 will now be described with reference to a detailed view shown in Figure 5. The mounting ring 40 is a cylindrical rim 42 having an outer circumferential side 44 and an inner circumferential side 46. The outer circumferential side 44 supports a concentric inwardly depending flange 48 provided with a plurality of apertures 50 disposed therein at regular intervals therearound. The concentric flange 48 is arranged, in use, to be mounted in close facing arrangement on a wheel hub (not shown) by means of fastening devices, such as bolts, received in the apertures 50. In other embodiments, the inwardly depending flange 48 may be disposed proximal the outer circumferential side 44 or spaced apart from the outer circumferential side 44.

The mounting ring 40 is also provided with a pair of correspondingly shaped concentric flanges 52a, 52b outwardly depending from the outer and inner sides 44, 46, respectively of the cylindrical rim 42 so as to define a channel 54 therebetween. The flanges 52a, 52b are provided with a plurality of correspondingly aligned apertures 56 disposed proximal to the cylindrical rim 42. The concentric flange 52a may be thicker than the concentric flange 52b, although it will be appreciated that in most cases the concentric flanges 52a, 52b are the same thickness.

The channel 54 defined by the flanges 52a, 52b is configured to receive the nave plate 20 therein, as shown in Figures 1, 2, 7 and 8. The channel 54 is marginally wider than the width of the nave plate 20. The width of channel 54 corresponds to the length of the inner circumferential sleeve 36 so that side walls of the flanges 52a, 52b abut opposing ends of the inner circumferential sleeve 36 as depicted in Figure 8. In this way, a small degree of clearance is provided to accommodate lateral "bulging" of the side walls 37 of the annulus of resilient material when the resilient member 30 contracts in response to a load applied to the solid tyre rim base 12.

In these views, the nave plate 20 is shown as being fastened on opposing sides to the concentric flanges 52a, 52b by means of the plurality of fastening devices 38 which transversely extend through respective resilient members 30 embedded in the nave plate 20 and the correspondingly aligned apertures 56 disposed in the concentric flanges 52a, 52b. In use, the nave plate 20 is engaged with the mounting ring 40 by a two step sequence as shown in Figures 6 and 7. Figure 6 illustrates the initial aligning of complementary surfaces of the nave plate 20 and the mounting ring 40 to facilitate relative lateral translation between the flange 52b and the nave plate 20 to an extent where the nave plate 20 is disposed within the channel 54. Figure 7 demonstrates subsequent relative rotation between the mounting ring 40 and the nave plate 20 to laterally align apertures 56 with the spaces defined by the inner circumferential sleeve 36 so that respective fastening devices 38 can be extended therein to fasten the nave plate 20 and the mounting ring 40 in a close facing arrangement as shown in Figures 1, 2, and 8.

The mounting ring 40 may be disengaged from the nave plate 20 by following a reverse of the above sequence.

In order to facilitate lateral translation of the flange

52b relative to the nave plate 20, it is important that the flanges 52a, 52b and the nave plate 20 have complementary shaped surfaces with respect to one another. As shown in the embodiment illustrated in the accompanying figures, the flanges 52a, 52b have a plurality of substantially sinusoidal lobes 58 radially extending relative to a central rotational axis of the solid tyre wheel assembly 10 in an arrangement whereby each lobe 58 accommodates one aperture 56 therein.

The materials of construction of the nave plate 20 and the mounting ring 40 of the solid tyre wheel assembly 10 described can be any suitable materials which wear appropriately, and that can be shaped, formed and fitted in the manner so described, and include an appropriate metal such as mild steel, metal alloys, or even ceramics, and so on . In the description of the invention, except where the context requires otherwise due to express language or necessary implication, the words "comprise" or variations such as "comprises" or "comprising" are used in an inclusive sense, i.e. to specify the presence of the stated features, but not to preclude the presence or addition of further features in various embodiments of the invention.

It is to be understood that, although prior art use and publications may be referred to herein, such reference does not constitute an admission that any of these form a part of the common general knowledge in the art, in Australia or any other country.

Numerous variations and modifications will suggest themselves to persons skilled in the relevant art, in addition to those already described, without departing from the basic inventive concepts. All such variations and modifications are to be considered within the scope of the present invention, the nature of which is to be determined from the foregoing description.

Claims

The Claims defining the invention are as follows:

1. A wheel assembly comprising: a rim base arranged for receiving a tyre; a mounting portion connectable to a vehicle axle; and, a damping assembly in operative communication between the rim base and the mounting portion.

2. The wheel assembly according to claim 1, wherein, the damping assembly comprises one or more resilient members embedded in the -mounting portion in- an arrangement whereby the one or more resilient members deform in response to a load applied to the rim base.

3. The wheel assembly according to claim 2, wherein the mounting portion comprises a nave plate concentrically supported on the rim base, the nave plate having a plurality of apertures therein, the apertures being configured to receive the one or more resilient members.

4. The wheel assembly according to claim 3, wherein the wheel assembly is provided with a pair of nave plates spaced apart from one another.

5. The wheel assembly according to claim 4 wherein the pair of nave plates are substantially equidistantly spaced from side edges of the solid tyre rim base.

6. The wheel assembly according to any one of claims 2 to 5, wherein the resilient member comprises an annulus formed from resilient material.

7. The wheel assembly according to claim 6, wherein the annulus has an outer circumferential sleeve and an inner circumferential sleeve.

8. The wheel assembly according to claim 7, wherein the inner circumferential sleeve is longer than the annulus .

9. The wheel assembly according to any one of claims 6 to 8, wherein opposing side walls of the annulus are substantially concave.

10. The wheel assembly according to any one of claims 3 to 9, wherein the apertures are equiangularly disposed within the nave plate proximal to the inner circumferential surface of the rim base.

11. The wheel assembly according to any one of claims 3 to 10, wherein the nave plate has a plurality of substantially sinusoidal lobes radially extending relative to a central rotational axis of the wheel assembly in an arrangement whereby each lobe accommodates one respective aperture therein.

12. The wheel assembly according to any one of claims 6 to 11, wherein the apertures are cylindrically shaped.

13. The wheel assembly according to claim 12, wherein respective resilient members can be press-fitted into the cylindrically shaped apertures.

14. The wheel assembly according to any one of claims 3 to 13, the solid tyre wheel assembly further comprising a mounting ring supported by a respective wheel hub, wherein the mounting ring is arranged in use to be fastened to the nave plate by a plurality of fastening devices transversely extending through respective resilient members .

15. The wheel assembly according to claim 14, wherein each fastening device is configured to be received in a space defined by the inner circumferential sleeve of the respective annulus of resilient material.

16. The wheel assembly according to claim 14 or claim 15, wherein the mounting ring has a concentric flange, the concentric flange being arranged, in use, to be mounted in close facing arrangement on the wheel hub.

17. The wheel assembly according to any one of claims 14 to 16, wherein the mounting ring has two concentric flanges on the mounting ring so as to define a channel therebetween .

18. The wheel assembly according to claim 16, wherein the channel is configured to receive the nave plate therein.

19. The wheel assembly according to claim 16 or claim 17, wherein the nave plate is engaged in the channel by facilitating relative lateral translation between the nave plate and the mounting ring.

20. The wheel assembly according to claim 17 or claim 18, whereupon the nave plate is received in the channel, relative rotation between the mounting ring and the nave plate facilitates lateral alignment of the fastening devices with reciprocal apertures in the flanges, the reciprocal apertures being configured to receive the fastening devices and thereby fasten the mounting ring to the nave plate in a close facing arrangement.

21. The wheel assembly according to claim 18 or claim 19, wherein the flanges and the nave plate have complementary shaped surfaces with respect to one another to facilitate relative lateral translation between the flange depending from the inner circumferential side of the mounting ring and the nave plate.

22. The wheel assembly according to claim 20, wherein the flanges have a plurality of substantially sinusoidal lobes radially extending relative to a central rotational axis of the wheel assembly in an arrangement whereby each lobe accommodates one reciprocal aperture therein.

23. The wheel assembly according to any one of the preceding claims, wherein the tyre mounted on the rim base is a solid tyre.

24. The wheel assembly according to any one of claims 1 to 22, wherein the tyre mounted on the rim base is a

^■pneumatic tyre.