GB2067482A - Vehicle wheel rim - Google Patents

Abstract

A wheel rim has a ring part 25 carrying a tyre retaining flange 28 and defining a tyre bead seat 26, a further part 10, 11, 12 also carrying a tyre retaining flange 17 and defining a tyre bead seat 16, a resilient sealing ring 24 between the parts 25 and 10, 11, 12, and a locking ring 35 arranged to retain the two parts 25 and 10, 11, 12 together so that the sealing ring 24, which is engaged in a recess 23 in the part 10, 11, 12, is sealingly engaged against a surface 34 of the ring part 25, the surface 34 being generally convex and of a non stepped configuration. The surface 34 may have a substantially cylindrical axially inner part and a frusto-conical outer part meeting at a rounded corner engaging the ring 24. A lug 21 snap-engaged over the locking ring 35 is received in notches 20, 32 in the parts 10, 11, 12 and 25 respectively to prevent relative rotation between the parts. <IMAGE>

Description

SPECIFICATION Vehicle wheel rim This invention relates to vehicle wheels rims of the kind constructed from a number of components including two rim parts which carry or are directly connected with respective tyre retaining flanges and defining respective bead seat portions, one of these parts being in the form of a ring having an internal surface against which a resilient sealing ring engages, said sealing ring being located in a recess in the other of said parts orto a further part secured to said other part, the ring forming said one part being retained, in the assembled condition, in sealing engagement with the sealing ring by a detachable fastening means. Such a rim will for convenience be referred to as being of the kind specified.

A known rim of this kind is provided on the internal surface of the ring, with a step which is arranged in assembled condition to engage and compress the sealing ring, by pressing into it. The sealing ring being of rubber or similar resilient material spreads into the gap defined between the ring and the part in which the sealing ring is engaged to form an airtight seal. However, sliding of the ring to engage the sealing ring sometimes causes uneven distortion of the sealing ring and thus failure to achieve an airtight seal. Furthermore, the tolerances to which the parts are made must be very small in order to avoid leakage of the seal due to ovality of the parts, or other out of round distortion or inexact matching of the ends of the material from which the rim parts are constructed, from initially flat or straight stock.Any such inexact matching may necessitate grinding by hand and this must be undertaken with the greatest of care if the stepped form is to be maintained to provide a continuous surface on which the sealing ring will bear evenly.

It is therefore the object of the invention to provide a wheel rim of the kind specified in which these and other disadvantages of the known, stepped form of the ring internal surface are overcome or substantially reduced, so that a reliable seal can be achieved.

According to the invention a wheel rim of the kind specified is provided on said ring with an internal surface of generally convex, non stepped configuration against which, in use, said sealing ring engages.

The invention will now be described by way of example with reference to the accompanying drawings, in which: Figure lisa cross-sectional view of a wheel rim constructed in accordance with the invention, and Figure 2 is an enlarged section of part of the rim showing the sealing arrangement.

Figure 1 shows a wheel rim for a large vehicle, such as an earthmover. The rim is constructed from a number of parts some of which are made from hot rolled section and some of which are made from initially flat strip material of relatively thin gauge.

The rim has uniform cross-section throughout and is attached to a disc (not illustrated) secured inter nallywithinthe rim by welding.

The rim in this example includes three parts 10,11, 12 forming a main section which extends substantially full width of the rim. However other numbers of interconnected parts may be substituted. These parts 10, 11, 12 are welded together as indicated at 13 and 14, respectively. The part 12 has an upstanding external flange 15 and forms a tyre bead seat surface 16. Between the tyre bead seat surface 16 and the end flange 15, is located a ring 17 forming a tyre retaining flange. This has a generally arcuate cross-section and both inner corners are chamfered or radiused at 18 and 19, respectively.

The part 11 of the main section of the rim is near flat but near its end connected to the part 12 it has a shallow joggle, as illustrated. Other configurations of multiple piece rim may be used.

The part 10 has a thickened end portion which at one position in its periphery, is notched at 20 to provide a location slot for a driving lug 21 which prevents relative rotation between parts of the rim, as will be described.

The part 10 has an elongated portion the end of which is connected to the part 11, in which is formed an inflation valve hole 22. Between the thickened end portion with the notch 20 and the elongated portion of the part 10 is a tapering section 22 of which the radially outwardly presented surface has a partcircular section annular recess 23. This part-circular recess 23 accepts a sealing eing 24, as will be described.

Engaged outside the main section made up of the parts 10, 11, 12 of the rim, is a tyre bead seat part 25 in the form of a ring with an external annular flange 27 at one end. The outwardly presented surface of this ring provides a shallowly inclined tyre bead seat surface 26. The flange of the ring 25 is slotted at one peripheral position to define a notch 32 to accept the driving lug 21. This lug therefore prevents rotation between the part 10 and the part 25. Engaging the ring 25, and resting against its flange 27 is a ring 28 of form similar two the ring 17. This ring 28 has its inner corners chamfered or radiused at 30, and 31 respectively.

The ring 25 tapers at its end remote from its flange 27 and it lies adjacent the external surfaces of the parts 10 and 11, in this case, overlapping the welded joints 13 between them, though in other cases, the welded joints may be otherwise placed.

The internal surface of the ring 25 incorporates a shallow, tapering section recess 33 terminating at its depper end at a position close to but spaced from the assembled position of the sealing ring 24.

A surface 34 of the ring 25, shown more clearly in Figure 2, is arranged to engage the sealing ring 24.

This surface 34 has a portion 34a which is substantially parallel with the axis of the rim, being therefore substantially cylindrical. A further portion 34b of the surface 34 is of tapering or shallow part-conical form, of which the larger diameter is towards the flanged end of the ring 25. The surface portions 34a, 34b join at a position indicated at 34e which is not however a sharp corner but is smoothly rounded so that the surface portions merge one into the other.

Figure 2 indicates the unstressed form of the sealing ring 24. This ring is formed from a resilient material, such as rubber or a rubber-like plastics material. The cross-sectional form of the sealing ring as shown in Figure 2 is initially circular, but when in a position of use, it becomes deformed into the condition shown in Figure 1, in which it becomes partially extruded into the gap formed between the part 10 and the ring 25. The junction 34e of the surface portions 34a, 34b of the ring 25 is located within the boundary defined by the unstressed configuration of the sealing ring 24 as indicated in Figure 2.

To secure the ring 25 with respect to the main section of the rim, formed by the parts 10, 11,12 constant cross-section split locking ring 35 is provided.

The driving lug 21 engages over and partly encompasses this. The lug 21 is fitted by deflecting its ends so that it snap engages on the ring 35. The locking arrangement is conventional. Tyre inflation causes the ring 25 to move and this has the effect of compressing the sealing ring 24 as the tyre is fitted to the rim. The tyre inflation forces the ring 25 and the ring 28 to the left shown in both the Figures of the drawings and the surface 34b of shallow conical form provides smooth transition between the initial circuwar form of the sealing ring 24 and its compressed fitted position as indicated in Figure 1. The end or corner of the ring 25is chamfered at 36 to aid correct initial compression of the sealing ring 24.

The sealing ring 24 provides a fully airtight seal to prevent escape of any air from within the tyre which is fitted to the rim. This is of particular importance where the tyre is of the tubeless form. The seal may be reliably fitted with this arrangement and undesirable distortion of the sealing ring leading to air leakage is minimised by the configuration of the surface 34 on the ring 35. The ring 25 may be made from initially flat material bent into the form of a ring and welded. At the welded junction an accurate surface and any small misalignment can be corrected by grinding of the surface 34 and the smooth form of that surface allows such grinding to be carried out with accuracy.

The precise form of the rim shown is pnly one example of a rim to which the sealing arrangement can be applied. Any multiple piece rim can be used where similar sealing arrangements are incorporated.

Claims (3)

1. Awheel rim including two rim parts carrying or being directly connected to respective tyre retaining flanges and defining respective bead seat portions, one of said rim parts being in the form of a ring having an internal surface against which a resilient sealing ring engages, the sealing ring being located in a recess in the other of the said rim parts or a part secured thereto, and a detachable fastening means arranged to retain said ring, forming said one part, in sealing engagement with the sealing ring, wherein said ring has an internal surface of generally convex, non, stepped configuration against which, in use, said sealing ring engages.

2. Awheel rim as claimed in claim 1 wherein the internal surface of said ring includes a generally cylindrical surface portion and a further surface portion of shallow part-conical form, these surface portions being joined by a smoothly rounded convex portion.

3. Awheel rim substantially as hereinbefore described by way of example with reference to and as shown in the accompanying drawings.