GB2342323A

GB2342323A - Pneumatic tyre and wheel assembly with tyre bonded to rim

Info

Publication number: GB2342323A
Application number: GB9821348A
Authority: GB
Inventors: Eric Thomas Watson Fyfe
Original assignee: Sumitomo Rubber Industries Ltd
Current assignee: Sumitomo Rubber Industries Ltd
Priority date: 1998-10-02
Filing date: 1998-10-02
Publication date: 2000-04-12
Anticipated expiration: 2018-10-02
Also published as: GB9821348D0; GB2342323B

Abstract

The wheel rim 2 has axially spaced cavities 9 in which the tyre ply endings 6 are embedded in a solid material 10 which fills the remaining volume of each cavity 9. The material 10 may be injected into the cavities 9 and may be a thermoplastic or thermosetting material, eg a rubber/liquid polymer or epoxy or polyester resin. In a modification, fig.2, the wheel rim comprises a separate side ring 23, with injection ports 24, which may be attached after the ply ending has been inserted into cavity 21. The ply endings may be looped to assist in anchoring the tyre to the wheel rim. The tyre may be vulcanised before or after attachment to the rim.

Description

TYRE AND WHEEL RIM ASSEMBLY The present invention relates to an improved assembly of a tyre on a wheelrim and a method of manufacture thereof.

The conventional wheel assembly comprises a tyre and a wheelrim, each manufactured entirely separately often by different companies and only brought together at the point of use.

To ensure safety and satisfactory uniformity performance of such an assembly, it is necessary to have the fit between the tyre and the wheel rim correctly engineered and predictably reproduced.

Thus the bead and bead base of the tyre require the correct material properties and shape to match the bead seat and flange profile of the wheelrim and the various tolerances of these features need to be very closely controlled.

In view of the above requirements tyre beads have evolved to become relatively bulky, hard and highly reinforced and the bead base to have a large projected area to ensure provision of an airtight seal and resistance to rocking.

The provision of such requirements in the tyre and the wheelrim is thus expensive and restricting to both the tyre manufacturer and the wheelrim producer.

It is an object of the present invention to provide an assembly of a tyre on a wheelrim and a method of manufacture thereof which is both simpler and less expensive and which ensures a safe and reliable fit of the tyre on the rim.

Thus according to the present invention there is provided an assembly of a tyre on a wheelrim, the wheelrim comprising a cylindrical tyre support rim having circumferentially extending spaced-apart cavities, one at each axial edge of the wheelrim, a tyre comprising a ground contacting tread flanked on either side by a radially inwardly extending sidewall and a carcass reinforcing ply extending through the tread and sidewalls and terminating in ply endings substantially radially inwardly of the sidewalls, each of the ply endings being located in one of the cavities in the rim and embedded in solidified material therein to anchor the ply ending in the cavity.

Preferably the spaced-apart cavities are disposed on the radially outer side of the wheelrim.

One or both of the cavities may be part-formed by a separate side-ring fixed to the axial edge of the rim.

The solidified material embedding the ply endings may be a thermoplastic material or a thermosetting material. It may comprise a rubber compound, an epoxy resin or a polyester resin.

One or both of the cavities in the rim may have an axial width which is greater in the radially inner part than the outer part to assist in anchoring the ply ending.

According to another aspect of the present invention a method of manufacturing an assembly of a tyre on a wheelrim comprises assembling a tyre envelope comprising a ground contacting tread flanked on either side by a radially inwardly extending sidewall and having a carcass reinforcing ply extending through the tread and sidewalls and terminating in ply endings radially inwardly of the radially inner end of each of the sidewalls, providing a wheelrim comprising a cylindrical tyre support rim having circumferentially extending spaced apart cavities, one at each axial edge of the rim, inserting one of the two ply endings of the tyre into each of the spaced apart cavities in the wheelrim and subsequently filling the cavity with a settable material to anchor the ply ending in the cavity.

Further aspects of the invention will become apparent from the following description, by way of example only, of embodiments of the invention in conjunction with the following drawings in which: Figure 1 shows a schematic view of a scrap cross-section of a tyre and wheelrim assembly according to a first embodiment of the invention; and Figures 2 and 3 show schematic views of a scrap cross-section of an assembly according to a second embodiment of the invention.

Shown in Figure 1 is a part cross-section of a pneumatic tyre 1 mounted on a wheelrim 2. The tyre envelope comprises a ground contacting rubber tread 3 flanked on either side by rubber sidewalls 4.

Extending through the tread and sidewalls is a carcass ply 5 comprising a plurality of radially extending reinforcing cords. At the radially inner parts of the tyre the carcass ply 5 extends beyond the radially inward end of the sidewall 4 to form exposed ply endings 6.

The wheelrim 2 comprises the conventional configuration of a cylindrical rim part 7 surrounding a disc-shaped nave part 8. Spaced apart at each axial edge of the rim 7 are circumferentially extending cavities 9 open to the radially outer surface of the rim 7. The cavities 9 have an axial width in their radially outer part which is narrower than the width in the inner part.

In the assembly of the tyre on the wheelrim each of the ply endings 6 are disposed within the corresponding cavity 9 in the wheelrim and embedded therein in a solid material 10 which fills the remaining volume of the cavity to anchor the tyre 1 onto the wheelrim 2.

The solid material 10 which fills the wheelrim cavity may comprise any suitable material which is capable of being introduced by suitable means such as fluid injection into the cavity but which subsequently sets or solidifies. Such materials include thermoplastic or thermosetting materials.

Suitable materials may include rubber/liquid polymers or epoxy or polyester resins which are subsequently cross-linkable either with or without heating.

In another embodiment of the invention shown in Figures 2 and 3 the cavity 30 is formed in part by a cavity 21 in the wheelrim 20 and completed by a cavity 22, formed in a separate side ring 23 which is fitted to the wheelrim 20 either before or preferably, as shown, after the ply ending has been inserted into position. The side ring 23 may if necessary be provided with suitable means for locking to the wheelrim 20.

This separate side ring may have, as shown, one or more ports or injection holes 24 to facilitate the filling of the formed cavity 30 with the solidifiable material.

The carcass reinforcing ply may comprise cut sheet fabric or it may comprise one or more continuous reinforcements wound from the tread region radially inwardly through the sidewall and then back again radially outwardly to the tread whereby the ply ending is formed in a loop. Such loops further assist in anchoring the tyre to the wheelrim. Such continuously wound reinforcement may be wound entirely across the tyre envelope or be wound as two separate plies from the tread through each adjacent sidewall.

According to the method of the invention the components of the tyre envelope are assembled and then may be vulcanised before assembly onto the wheelrim or alternatively the tyre envelope may be assembled onto the wheelrim and then vulcanised. In the latter the whole assembly may be placed inside a heated mould and the interior space between the tyre envelope and the wheelrim may be then pressurised to bring the exterior surface of the tyre into contact with the mould. The pressurising medium may also be heated to assist in vulcanisation of the envelope.

This vulcanisation process may also be used to cause the solidification of the material anchoring the ply endings in the wheelrim cavity.

Whilst the above embodiments have described a tyre envelope wherein the ply endings are not anchored to any kind of conventional annular bead hoop by being turned around such a hoop or otherwise, the present invention does not exclude such a configuration which can be much simplified and reduced compared to a conventional tyre bead. In such a construction the bead hoop and ply endings may together be anchored in the cavities.

Further whilst the above embodiments show the spaced-apart cavities formed on the radially outer side of the wheelrim they may be formed elsewhere on the wheelrim such as the axial edges or the radially inward surface.

Claims

CLAIMS 1. A wheel assembly comprising a wheelrim comprising a cylindrical tyre support having circumferentially extending spaced-apart cavities, one at each axial edge of the wheelrim, a tyre comprising a ground contacting tread flanked on either side by a radially inwardly extending sidewall and a carcass reinforcing ply extending from the tread through the sidewalls and terminating in ply endings substantially radially inwardly of each sidewall, each of the ply endings being located within one of the cavities in the rim and therein embedded in a solidified material to anchor the ply ending in the cavity.
2. A wheel assembly according to claim 1, wherein the spaced-apart cavities are formed on the radially outer side of the wheelrim
3. An assembly according to either of claims 1 or 2, wherein at least one cavity is part-formed by a separate side-ring fixed to the axial edge of the rim.
4. An assembly according to any of claims 1 to 3, wherein the solidified material comprises a thermoplastic material.
5. An assembly according to any of claims 1 to 3, wherein the solidified material comprises a thermosetting material.
6. An assembly according to claim 5, wherein the solidified material comprises one or more of a rubber compound, an epoxy resin or a polyester resin.
7. An assembly according to any of claims 1 to 6, wherein the at least one of the cavities in the rim has an axial width which is greater in the radially inner part than the outer part to assist in anchoring the ply ending.
8. A method of manufacturing an assembly of a tyre on a wheelrim, comprising assembling a tyre envelope comprising a ground contacting tread flanked on either side by a radially inwardly extending sidewall and having a carcass reinforcing ply extending from the tread through sidewalls and terminating in ply endings radially inwardly of the radially inner end of each of the sidewalls, providing a wheelrim comprising a cylindrical tyre support rim having circumferentially extending spaced apart cavities, one at each axial edge of the rim, inserting one of the two ply endings of the tyre into each of the spaced apart cavities in the wheelrim and subsequently filling the cavity with a settable material to anchor the ply ending in the cavity.
9. A method according to claim 8, characterised in that the tyre envelope comprises vulcanise elastomeric materials.
10. A method according to claim 8, comprising vulcanising the tyre envelope prior to assembling it onto the rim.
11. A method according to claim 8, comprising vulcanising the tyre after assembling it onto the rim.
12. A method according to claim 11, comprising placing the assembly of the unvulcanised tyre envelope on the rim inside a heated mould, pressurising the interior space between the tyre envelope and the rim to bring the exterior surface into contact with the heated mould so to shape and vulcanise the tyre.
13. A method according to any of claims 8 to 12, characterised in that the settable material comprises a vulcanisable elastomer.
14. A method according to any of claims 8 to 12, wherein the settable material comprises a thermosetting resin.
15. A method according to any of claims 8 to 12, wherein the settable material comprises a thermoplastic resin.