Runflat assembly

Abstract

There is provided a runflat assembly comprising: a runflat (22) made of a resilient material, wherein the runflat (22) is shaped to define a receptacle (26); and a support member (24) inserted inside

Description

The invention relates to a runflat assembly, a wheel assembly comprising a runflat assembly and a method of installing a runflat assembly onto a wheel. In a number of instances, runflat assemblies are provided for vehicle wheels. Such assemblies generally comprise an annular ring that fits around a wheel inside of the tyre. This blocks off the well of the wheel where provided, and also provides a ground engaging surface around the wheel, upon which surface a vehicle can run in the event of deflation of a tyre. Previous runflat assemblies have often used a substantially rigid annular member made of, for instance, a composite material. Such materials are used to provide sufficient strength and wear resistance during use. However, such ground engaging members tend to provide a very hard ride. Moreover, such members, as well as the wheel and suspension of the vehicle on which the assembly is fitted, can be damaged upon application of a high impact force thereagainst. Such forces could be encountered when engaging or mounting a kerb, or driving off road for example. According to a first aspect of the invention, there is provided a runflat assembly comprising: a runflat made of a resilient material, wherein the runflat is shaped to define a receptacle; and a support member inserted inside the receptacle. The configuration of the invention enables the runflat assembly to, for example, mount kerbs and drive off road without causing damage to the support member that is cushioned by the resilient runflat. The resiliency of the runflat thus provides for an improved and more comfortable ride while the support member inserted inside the receptacle of the runflat helps to reinforce the runflat, thereby maintaining the integrity of the runflat and extending the duration of usability of the runflat assembly. Furthermore, the provision of discrete components in the form of the runflat and support member enables the tailoring of the properties of the runflat and support member separately in a way that improves the runflat assembly, without requiring replacement or substantial redesign and modification of the runflat and the support member. In particular, as described later in this specification, the shape, construction and material of the support member may be tailored to provide the support member and therefore the runflat assembly with desired properties, such as lightweightness and mechanical strength. The runflat may be shaped to define a single receptacle or a plurality of receptacles. The single receptacle may extend across part or the whole of the length of the runflat. The plurality of receptacles may be spaced apart from each other. The number of the plurality of receptacles may be two, three, four, five, six or more. In embodiments of the invention, the receptacle may be an open-sectioned receptacle. Preferably the receptacle has a U-shaped cross-section, a quadrilateral-shaped crosssection or a trapezoidal-shaped cross-section. Indeed, the receptacle may have any shape capable of receiving the support member. In further embodiments of the invention, the support member may be attached to a surface of the receptacle (e.g. a base and / or a wall of the receptacle). For example, the support member may be bonded to the surface of the receptacle (e.g. the base and / or wall of the receptacle). This maintains the position of the support member inside the receptable and thereby improves the integrity of the runflat assembly. In other embodiments of the invention, the support member may be removable from the receptacle. That is to say, the support member may be either not attached to the receptacle or may be only temporarily attached to the receptacle. This allows for the replacement of either the runflat or support member when either component is damaged or worn down. The shape and construction of the support member may vary due to, for example, the desired reinforcement provided by the support member and / or weight of the support member. In a preferred embodiment of the invention, the support member may include a body and at least one wing. The at least one wing may extend away from the body. The support member may include two wings, or a plurality of pairs of wings, extending away from opposite sides of the body. The at least one wing may abut a surface of the receptacle but in other embodiments may be spaced apart from the surface of the receptacle. In other embodiments of the invention, the support member may omit the at least one wing. The length of the or each wing may vary. For example the length of the or each wing may be less or more than half of a width of the support member, or may be less or more than a quarter of a width of the support member. The length of the or each wing may be kept short in order to handle heavy duty applications. The support member may be shaped as either an open-sectioned support member or a closed-sectioned support member. When the support member is shaped as an opensection support member, the support member preferably has a U-shaped crosssection, a quadrilateral-shaped cross-section ora trapezoidal-shaped cross-section. The body of the support member may be hollow. For example, at least part of the support member may have a lattice or honeycomb structure. This is so that the support member is provided with a lightweight structure without compromising on the strength of the support member. The runflat assembly may include a single support member inserted inside the receptacle. Alternatively, the runflat assembly may include a plurality of support members inserted inside the receptacle. Preferably the support members are spaced apart from each other inside the receptacle. The runflat assembly may include a plurality of support members, each of which is inserted inside a respective one of a plurality of receptacles. It will be appreciated that the or each support member may be configured to partially or completely extend along a circumferential length of the runflat when inserted inside the receptacle. When a plurality of support members is employed, the support members in combination may partially or completely extend along a circumferential length of the runflat when inserted inside the receptacle(s). The material of the support member may vary depending on the required properties of the runflat assembly. Different materials may be chosen for the support member depending on the target application of the runflat assembly, such as for wheels of passenger cars, buses and heavy vehicles. In embodiments of the invention, the support member may be made of a material that is lower in density than the resilient material of the runflat. Manufacturing the support member from a material that is lower in density than the resilient material of the runflat results in an overall weight reduction of the runflat assembly, without adversely affecting the contributions of the runflat and the support member to the function of the runflat assembly. In further embodiments of the invention, a compressive strength of the support member may be higher than a compressive strength of the runflat. This allows the support member to provide the desired reinforcement to the runflat. The material or materials of the runflat assembly may vary depending on the desired properties of the runflat assembly. The resilient material may be, but is not limited to, rubber, a rubber-based composite or compound, polyurethane or a polyurethane-based composite or compound. The resilient material may be natural rubber, M049 rubber compound, M059 rubber compound, C779 rubber compound or a combination of any thereof. The support member may be made of, but is not limited to, a metallic material or composite, an alloy material or composite, a carbon or a carbon-based composite or compound, or a polymer, or a polymer-based composite or compound. For example, the support member may be made of a nylon-based or plastic material. The polymer or polymer-based composite may be a thermoplastic or thermoset material. Such materials are particularly useful for configuring the support member to be lower in density than the resilient material of the runflat so as to provide weight reduction. In addition, the polymer material may be chosen to possess excellent mechanical strength to provide the runflat with the desired reinforcement. The support member may be fabricated using a variety of manufacturing processes that include, but are not limited to, moulding, additive manufacturing and 3D printing. Preferably the runflat has an arcuate shape and / or wherein the support member has an arcuate shape. More preferably the arcuate shape is a fully or partly circular shape. The runflat preferably has an annular shape. This is so that the runflat and / or support member matches the circular shape of a wheel. According to a second aspect of the invention, there is provided a wheel assembly comprising a wheel, a runflat assembly according to any one of the first aspect of the invention and its embodiments mounted around the wheel, and a tyre mounted around the runflat assembly, wherein the support member is located between the runflat and wheel. Optionally the tyre may be mounted around the runflat assembly so that an interior surface of the tyre engages with the runflat. The support member may or may not be mounted on the wheel. In the case of the former, preferably the support member is mounted directly on the wheel, but in other embodiments the support member may be mounted indirectly on the wheel via an intermediate component, layer or member arranged between the support member and the wheel. The features and advantages of the first aspect of the invention and its embodiments apply mutatis mutandis to the second aspect of the invention and its embodiments. According to a second aspect of the invention, there is provided a method of installing a runflat assembly onto a wheel, wherein the runflat assembly comprises a runflat and a support member, wherein the runflat is made of a resilient material and is shaped to define a receptacle, the method comprising the steps of: mounting the runflat around the wheel; and inserting the support member inside the receptacle, wherein the support member is located between the runflat and wheel. The features and advantages of the first and second aspects of the invention and their embodiments apply mutatis mutandis to the third aspect of the invention and its embodiments. The method according to the invention may include the step of inserting the support member inside the receptacle prior to mounting the runflat around the wheel. The method according to the invention may include the step of placing the runflat inside a tyre prior to mounting the tyre around the wheel. The method according to the invention may include the step of attaching (e.g. bonding) the support member to a surface of the receptacle. The method according to the invention may include the step of inserting the support members inside the receptacle so that the support members are located between the runflat and wheel. Furthermore, the method according to the invention may include the step of inserting the support members to be spaced apart from each other inside the receptacle. It will be appreciated that the use of the terms "first" and "second", and the like, in this patent specification is merely intended to help distinguish between similar features, and is not intended to indicate the relative importance of one feature over another feature, unless otherwise specified. Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, and the claims and / or the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and all features of any embodiment can be combined in any way and / or combination, unless such features are incompatible. The applicant reserves the right to change any originally filed claim orfile any new claim accordingly, including the right to amend any originally filed claim to depend from and / or incorporate any feature of any other claim although not originally claimed in that manner. Preferred embodiments of the invention will now be described, by way of non-limiting examples, with reference to the accompanying drawings in which: Figure 1 shows a runflat assembly according to an embodiment of the invention; Figures 2 and 3 show a runflat of the runflat assembly of Figure 1; Figures 4, 5 and 6 show a support member of the runflat assembly of Figure 1; Figure 7 shows the support member inserted inside a receptacle of the runflat; and Figure 8 shows an exemplary method of installing a runflat assembly onto a wheel. The figures are not necessarily to scale, and certain features and certain views of the figures may be shown exaggerated in scale or in schematic form in the interests of clarity and conciseness. A runflat assembly according to a first embodiment of the invention is shown in Figure 1 and is designated generally by the reference numeral 20. The runflat assembly 20 comprises a runflat 22 and a plurality of support members 24. The runflat 22 has an arcuate shape so as to be fully circular and annular, i.e. a ring shape. Each support member 24 has an arcuate shape so as to be partly circular. Figures 2 and 3 show the runflat 22 in further detail. The runflat 22 is shaped to define a receptacle 26 in the form of a channel that extends across the whole of a circumferential length of the runflat 22. In other embodiments, the receptacle may extend across part of a circumferential length of the runflat. The receptacle 26 is configured as an open-sectioned receptacle with a U-shaped cross-section, as shown in Figures 2 and 3. The receptacle 26 may have a differently shaped cross-section, non-limiting examples of which are described throughout the specification. The runflat 22 is made of a resilient material. The resilient material may be, but is not limited to, rubber, a rubber-based composite or compound, polyurethane or a polyurethane-based composite or compound. The resilient material may be natural rubber, M049 rubber compound, M059 rubber compound, C779 rubber compound or a combination of any thereof. Figures 4, 5 and 6 show the support member 24 in further detail. Each support member 24 is configured as a closed-sectioned support member that includes a hollow body 28 and a pair of wings 30. The hollow body is shaped to define an undercut. In the embodiment shown, the undercut results in the hollow body having a mushroomlike cross-section shape. Other forms of undercuts are envisaged, and the height and depth of the undercut may vary. It is also envisaged that the undercut is omitted altogether. The wings 30 are attached to, and extend away from, opposite sides of one end of the body 28. Preferably the body 28 and wings 30 are constructed to have a lattice or honeycomb structure as shown in Figure 4, which may be achieved using additive manufacturing and 3D printing. The support member 24 may be made of, but is not limited to, a polymer or a polymerbased composite or compound. For example, the support member 24 may be made of a nylon-based or plastic material. The polymer or polymer-based composite may be a thermoplastic or thermoset material. The material of the support member 24 is selected to be lower in density than the resilient material of the runflat 22. In addition, the material and construction of the support member 24 are preferably selected so that a compressive strength of the support member 24 is higher than a compressive strength of the runflat 22. Configuration of the support member 24 in this manner not only results in an overall weight reduction of the runflat assembly 20 but also enables the support member 24 to provide a desired level of reinforcement to the runflat 22. The support members 24 are inserted inside the receptacle 26. Figure 7 shows a crosssection along the line A-A of Figure, showing the insertion of a support member 24 inside the receptacle 26. The body 28 of each support member 24 abuts a base of the receptacle 26, while the wings 30 of each support member 24 abut sidewalls of the receptacle 26. Preferably the body 28 is bonded to the base 32 of the receptacle 26 and / or the wings 30 are bonded to the sidewalls 34 of the receptacle 26. Such bonding may be performed using an adhesive and / or heat treatment. As shown in Figure 1, the support members 24 are equidistantly spaced apart from each other about a circumferential length of the runflat. The number of support members 24 is six but may be a different number in other embodiments. Furthermore, the spacing between the support members may vary in other embodiments. The runflat assembly 20 according to the invention is comprised in a wheel assembly together with a wheel and a tyre. The runflat assembly 20 is mounted around the wheel, while the tyre is mounted around the runflat assembly 20. As a result, the support members 24 inside the receptacle 26 are located between the runflat 22 and wheel. Optionally an interior surface of the tyre engages with the runflat 22. An exemplary method of installing a runflat assembly 20 onto a wheel is described as follows, with reference to Figure 8: 1) 36 - Initially the runflat 22 is placed inside the tyre. 2) 38 - The support members 24 are then inserted inside the receptacle 26 of the runflat 22 so to be equidistantly spaced apart from each other along the circumferential length of the runflat 22. 3) 40 - The support members 24 are bonded to surfaces 32,34 of the receptacle 26. 4) 42 - The tyre and runflat assembly 20 are then mounted around the wheel so that the support members 24 are located between the runflat 22 and wheel. It will be appreciated that the order of the steps, and sub-steps, of the exemplary method of Figure 8 may vary and is not necessarily limited to the order shown in Figure 8. Due to the resilience of the runflat 22, the runflat assembly 20 can be used for instance to mount kerbs and drive off road without causing damage to the support members 24 that are cushioned by the resilient material. The resilient material of the runflat 22 also provides for an improved ride relative to previous runflat assemblies whilst the support members 24 reinforce the runflat 22 to maintain the integrity of the runflat 22 and thereby provides for prolonged use. Furthermore, the properties (such as shape, construction and material) of the runflat 22 and support member 24 can be individually tailored to obtain a desired performance of the runflat assembly 20, such as lightweightness and mechanical strength. In alternative embodiments, the runflat may be shaped to define a plurality of receptacles. Such receptacles may be equidistantly spaced apart from each other about a circumferential length of the runflat. The number of receptacles may vary in number. The spacing between the receptacles may vary. Each support member may be inserted in a respective one of the plurality of receptacles. In further alternative embodiments, the runflat may comprise a single support member inserted inside a single receptacle. The single support member may extend across part or the whole of a circumferential length of the runflat. The runflat and / or the support member may have a different shape. The size and / or shape of the runflat and support members will depend on the size of tyre fitted to the vehicle. The above embodiments are described with reference to a continuous annular runflat having a unitary structure. It will be appreciated that the runflat may be divided into several section parts, the number of which may vary. For example, a runflat may have only two section parts, particularly for use with smaller wheels. For very large wheels, it may be that at least three section parts are required. It will also be appreciated that the runflat may comprise any number of multiple section parts, such as four, five, six or more. The listing or discussion of an apparently prior-published document or apparently prior-published information in this specification should not necessarily be taken as an acknowledgement that the document or information is part of the state of the art or is common general knowledge. Preferences and options for a given aspect, feature or parameter of the invention should, unless the context indicates otherwise, be regarded as having been disclosed in combination with any and all preferences and options for all other aspects, features and parameters of the invention.

Claims

1. A runflat assembly comprising:a runflat made of a resilient material, wherein the runflat is shaped to define a receptacle; anda support member inserted inside the receptacle.

2. A runflat assembly according to Claim 1 wherein the receptacle is an open-sectioned receptacle.

3. A runflat assembly according to any one of the preceding claims wherein the support member is attached to a surface of the receptacle.

4. A runflat assembly according to Claim 1 or Claim 2 wherein the support member is removable from the receptacle.

5. A runflat assembly according to any one of the preceding claims wherein the support member includes a body and at least one wing, wherein the least one wing extends away from the body.

6. A runflat assembly according to Claim 5 wherein the least one wing abuts a surface of the receptacle.

7. A runflat assembly according to any one of the preceding claims wherein thesupport member is shaped as an open-sectioned support member.

8. A runflat assembly according to any one of Claims 1 to 6 wherein the support member is shaped as a closed-sectioned support member.

9. A runflat assembly according to any one of the preceding claims wherein at least part of the support member has a lattice or honeycomb structure.

10. A runflat assembly according to any one of the preceding claims including a plurality of support members inserted inside the receptacle.

11. A runflat assembly according to Claim 10 wherein the support members are spaced apart from each other inside the receptacle.

12. A runflat assembly according to any one of the preceding claims wherein the support member is made of a material that is lower in density than the resilient material of the runflat.

13. A runflat assembly according to any one of the preceding claims wherein a compressive strength of the support member is higher than a compressive strength of the runflat.

14. A runflat according to any one of the preceding claims wherein the resilient material is rubber, a rubber-based composite or compound, polyurethane or a polyurethane-based composite or compound.

15. A runflat assembly according to any one of the preceding claims wherein the support member is made of a metallic material or composite, an alloy material or composite, a carbon or a carbon-based composite or compound, or a polymer, or a polymer-based composite or compound.

16. A runflat assembly according to Claim 15 wherein the support member is made of a nylon-based or plastic material.

17. A runflat assembly according to any one of the preceding claims wherein the runflat has an arcuate shape and / or wherein the support member has an arcuate shape.

18. A runflat assembly according to any one of the preceding claims wherein the runflat has an annular shape.

19. A wheel assembly comprising a wheel, a runflat assembly according to any one of the preceding claims mounted around the wheel, and a tyre mounted around the runflat assembly, wherein the support member is located between the runflat and wheel.

20. A method of installing a runflat assembly onto a wheel, wherein the runflat assembly comprises a runflat and a support member, wherein the runflat is made of a resilient material and is shaped to define a receptacle, the method comprising the steps of:mounting the runflat around the wheel; andinserting the support member inside the receptacle,wherein the support member is located between the runflat and wheel.

21. A method according to Claim 20 including the step of inserting the support member inside the receptacle prior to mounting the runflat around the wheel.

522. A method according to Claim 20 or Claim 21 including the step of placing the runflat inside a tyre prior to mounting the tyre around the wheel.

23. A method according to any one of Claims 20 to 22 including the step of attaching 10 the support member to a surface of the receptacle.

24. A method according to any one of Claims 20 to 23 when dependent from Claim 7 or Claim 8, the method including the step of inserting the support members inside the receptacle so that the support members are located between the runflat and wheel.1525. A method according to Claim 24 when dependent from Claim 8, the method including the step of inserting the support members to be spaced apart from each other inside the receptacle.13

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