A VEHICLE WHEEL

Abstract: A vehicle wheel with an emergency running system is described which can be installed simply and practically with onboard tools as a result of a multi-part construction which has low weight and very good emergency running characteristics, and consists of two resilient support rings (7, 8) which are clamped by means of clamping and spreading segments (9) engaging against a multi-part shallow base rim (5) and the beads (4) of a pneumatic tyre (1) to provide a compact assembly.

Description: The invention relates to a vehicle wheel comprising a multi-part rim having bead seats and lateral rim flanges, a tubeless pneumatic tyre, in particular a radial tyre and also an emergency running system which is arranged on the trim between and in contact with the tyre beads. One prior art vehicle wheel, corresponding to the preamble of claim 1, is known from DE-C-28 51 187. The emergency running ring for this known vehicle wheel consists of rubber or other elastomeric material, is of one piece construction and sits with its foot part, which fully fills out the space between the tyre beads, on a flat base rim with an inclined shoulder. In the event of pressure loss occurring in the tyre the emergency running ring takes on a supporting function on the one hand and prevents, on the other hand, the tyre beads from moving off the bead seats, and the vehicle thereby loosing its directional stability and steerability. Vehicle wheels with metallic emergency running rings are also known, wherein the emergency running rings consist of several segments and are pressed against the base of the rim, with the segments being clamped relative to one another. It is also known to integrate lubricant reservoirs into the emergency running rings, with the reservoirs being opened in the emergency running situation and releasing the lubricant. A disadvantage of the above is the difficulty of installing the emergency running ring. The object underlying the present invention is thus to provide a vehicle wheel of the initially named kind which the special feature that the installation is made substantially easier with a simultaneous minimisation of weight, and above all to provide troublefree torque transmission between the rim and the emergency running ring. Accordingly, the present invention provides an emergency running system formed by two separate rings consisting at least in part of elastomeric material and clamping and spreading segments which engage in form-fitted manner between the support rings, and which can be braced by means of securing elements against the base of the rim and the rim flanges to provide a form-fitted, force transmitting assembly between the support rings, tyre beads and rim. By splitting up the emergency running system into two support rings and a clamping and spreading ring, which itself is preferably assembled from three segments, the installation is, on the one hand, made decisively easier and can be carried out by means of the customary tools which are carried on board the vehicle. On the other hand, a compact assembly is provided between the rim, the tyre beads and the emergency running system by means of the clamping and spreading segments which are anchored to the rim has by means of securing elements. This compact assembly does not become inoperable due to extreme loading in emergency running operation, nor due to external violence, such as for example if the tyre and wheel assembly is shot at and thus ensures the manoevrability of heavy and extremely heavy vehicles, so that they can maintain adequate speed over relatively large distances even under the most unfavourable circumstances. Furthermore action of the spreading segments and the resulting compression of the support rings leads to an advantageous compensation for any variations in the tyre dimensions in the bead region, which is advantageous having regard to the use of the emergency running system with tyres from different manufacturers. In order to achieve volume compensation during axial compression peripherally extending channels which preferably face the tyre beads may be formed in the support rings. The support rings preferably have a soft elastic sealing layer which is optionally vulcanised into place at the bead contacting side and/or in the wheel seating region with the sealing layer extending inwardly at the wheel rim contacting region in the form of a sealing lip, so that in the assembled state the sealing lips, of the two support rings overlap each other, and troublefree sealing of the tyre interior is obtained having regard to the multi-part rim by the compressive action of the clamping and spreading segments. In accordance with a further advantageous aspect a seal at the rim base is formed by means of a sealing band which extends over the entire width of the rim and engages beneath the tyre beads. Sealing strips are however preferably directly formed on the support rings, and indeed in such a way that, on the one hand, they engage beneath the respectively associated bead and, on the other hand, so that the sealing strips overlap in the central region. It is always important with this arrangement that the clamping and spreading segments are clamped without the intermediary of resilient layers, but rather directly against the respective wheel rim surface for which purpose corresponding support projections can be provided. For the purpose of obtaining a large area for the form-fitted coupling regions between the clamping and spreading segments and the wheel rim surface this coupling is preferably effected via interengaging projections and recesses. In many cases however the required ability to transmit high torques is already achieved simply in that each clamping and spreading segments is clamped against the rim by means of at least two securing screws, which penetrate the rim base and engage in threaded bores of the associated clamping and spreading segments. In accordance with yet another aspect of the invention the outer peripheral surface of the clamping and spreading segments, which form a composite ring in the installed state, is provided with a gripping profile, so that when the tread is a torn away and the terrain is difficult the drive power which is available can still be used as effectively as possible. The outer diameter of the support rings is preferably selected to be larger than the outer diameter of the inner ring formed by the clamping and spreading segments, which is preferably of metal, so that in the emergency running situation the tread is initially supported on the support rings. After deflated running and loss of the tread, which may take place after a relatively short time, the support rings themselves are directly effective, and indeed with a certain residual elasticity. The rigid inner ring which is in practice assembled only from the segments takes on the sole supporting function after corresponding wear of the rubber support rings. Further particularly advantageous embodiments of the invention are described in the subordinate claims. An embodiment of the invention will now be described by way of example only in more detail with reference to the drawings in which:- Fig.1 is a schematic partial cross-sectional view of a vehicle wheel in accordance with the invention Figs.2 to 4 are schematic representations to explain the installation of the emergency running ring for the vehicle wheel of Fig. 1 Fig.5 is a schematic partial cross=sectional view to explain the wedging and clamping principle of the emergency running ring, and Fig.6 is a schematic representation similar to the vehicle wheel if Fig. 1, with additional sealing strips beneath the tyre beads. Fig.1 shows a tubeless pneumatic tyre 1 which is in this example a radial tyre having a tread 2, sidewalls 3 and beads 4. The tyre 1 is mounted on a rim 5, which is a multi-part rim having the customary bead seats and lateral rim flanges 6. A wheel rim consisting of three segments is preferably used as the multi-part rim, however, in principle other desired multi-part rims can also be used, for example rims in which a rim flange or rim horn is formed as a separate part and is attached by screw means. An emergency running ring is mounted inside the pneumatic tyre 1 and consists of two rubber support rings 7, 8 and a wedge ring formed from metal clamping and spreading segments 9 attached centrally between the two support rings 7, 8. The clamping and spreading segments 9 are clamped against the rim 5 by means of securing screws 10 which engage through the rim base and engage threaded bores 13 in the clamping and spreading segments 9. This clamping and spreading segment 9 engage directly and in force-transmitting manner with the base of the rim. The clamping and spreading segments 9 have a wedge-shape in cross-section to press the support rings 7, 8 which consist of elastomeric rubber material, and optionally have internal reinforcement with a high contact force against the tyre beads 4 when the clamping and spreading segments are clamped against the rim 5 by means of the securing screws 10. This clamping together of the rim 5, beads 4, support rings 7,8 and the clamping and spreading segments 9 provides, in conjunction with the securing screws 10 which bring a direct force transmitting connection between the rim 5 and the clamping and spreading segments 9, a compact assembly which on the one hand can withstand all the loads which occur in emergency running situations, and also all external effects, to ensure an undisturbed torque transmission between the rim and emergency running system in all situations. The support rings 7, 8 are preferably provided with a soft elastic surface layer in the bead contacting region and the wheel rim base contacting region. This layer may for example be vulcanised into place, and advantageously contributes to the sealing of the pneumatic tyre and wheel assembly to allow use of a tubeless tyre. A sealing lip 14 expediently extends axially inwardly from each support ring 7, 8, with two sealing lips of the support rings 7, 8 overlapping each other and being pressed against the base of the rim by the clamping and spreading segments so that the required seal is ensured, even for rims which are built up from segments. Attention should be paid to the fact that the section is so selected in Fig. 1 that the direct bracing of the clamping and spreading segments 9 against the rim base, which can for example take place via webs or ribs, cannot be seen. One of the securing screws 10 is preferably simultaneously constructed and used as the valve for supplying inflation air to the tyre. In the radially outer region the clamping and spreading segments have centering projections 15 at both sides, which can also be realised by a throughgoing element which projects at both sides. These centering projections 15 engage in guide grooves 16 which are formed in the support rings 7, 8 or vice versa. The support rings 7, 8 are furthermore each provided with a peripheral retaining projection 17 for the clamping and spreading segments 9. (See Figs 2 & 6) In addition to the already described advantages of the compact assembly which is achieved between the emergency running ring, the pneumatic tyre and the rim on the one hand, and the possibility for disturbance-free transmission of higher torques which is present on the other hand, the vehicle wheel of the invention is above all characterised by its simple installation. Whereas known vehicle wheels of this kind which are equipped with emergency running rings require tyre installation presses and often also special tools, the vehicle wheel of the invention with emergency running ring can be installed without special presses and the like solely using tools available on board the vehicle. Thus so-called field installation is also possible. This installation which is simple to carry out, is explained with reference to Figs. 2 to 4. Fig. 2 shows the pneumatic tyre 1 into which the first support ring 7 has already been introduced. By splitting the emergency running system up into several components each support ring which is primarily rubber is comparatively simple to deform on its own and can thus be easily brought into an oval shape and introduced into the interior chamber of the tyre, optionally using a spreader for the tyre beads. Fig.3 shows the support rings 7, 8 and the clamping and spreading segments 9 inserted into the tyre 2. After the introduction of the support rings 7 and 8 the tyre beads 4 are spread apart with the aid of a spreader so that sufficient space is available for the insertion and alignment of the spreading segments 9. In this phase of the installation alignment of the clamping and spreading segments 9 relative to the support rings 7, 8 already occurs in that the centering projections 15 are disposed in the guide grooves 16 of the support rings 7, 8 so it is no longer possible for the segments 9 to fall back because of the retaining projections 17. This initial position makes later clamping possible. The installation of the multi-part rim can then take place. Fig.4 shows the state of the vehicle wheel after the removal of the holding bolts 18 and the installation of the multi-part rim 5, and also the screwing together of the latter with the clamping and spreading segments 9. It can be seen that in this phase of the installation the individual components still form a relatively loose assembly and the beads 4 do not yet firmly contact the rim flanges 6. Thus startings from the initial position shown in Fig. 4, the securing screws are tightened, and a pronounced axial spreading occurs, as a result of the wedge action between the clamping and spreading segments 9 and the support rings 7, 8. This leads, with simultaneous centering, to forces pressing the tyre beads 4 against the rim and against the rim flanges 6, and to a force transmitting connection being obtained between the rim 5 and the clamping and spreading segments. Comparatively small forces are required for the tightening of the clamping screws 10 and very high contact pressure forces can be obtained in the axial direction, as a result of the mechanical advantage or transmission ratio resulting from the wedge surfaces. During the clamping procedure stiffening ribs 19 which are provided above the rim flange region on the support rings 7, 8 at the tyre wall side are directly pressed against the inner wall of the tyre in the transition region from the bead to the sidewall. This results in an important stabilisation of the emergency running system in the radially outer region, which is very advantageous in the emergency running case. Channels 20 which are formed in the support rings 7, 8 facing the beads 4, and which preferably extend circumferentially, allow favourable volume compensation to be achieved during axial clamping. After the clamping and tightening process has been completed the emergency running ring adopts the position shown in Fig. 1. Fig.5. shows once again in schematic manner the process of axial clamping by means of the securing screws 10 which extend in the radial direction, with the right hand side of this representation showing the loose assembly between the clamping and spreading segments 9, the support ring 8, the bead 4 and the rim flange 6, whereas the final tensioned compact assembly of these elements is shown in the left hand part. The representation of Fig.6 shows an arrangement corresponding to the previously described embodiment, however, a particularly advantageous seal is provided at the rim base. This seal at the rim base is achieved by means of a continuous one-piece band which preferably extends over the entire rim width. However, sealing strips 21, 22 are preferably moulded onto the support rings 7, 8 and extend beneath the tyre beads 4 up to the rim flanges 6. Sealing strips 14 are likewise moulded onto the support rings 7, 8 and point towards the centre of the rim, with these sealing strips overlapping each other and being disposed between the rim base and the clamping and spreading segments 9. The above described drawings also make it clear that the vehicle wheel of the invention still retains its running stability, even when the tread is torn away, so that the vehicle can still travel under control over a large distance. During this the emergency running ring acts as a type of solid rubber tyre, which can however transmit a particularly high torque as a result of the compact assembly and the fore transmitting connection with the rim.

Claims: 1. A vehicle wheel comprising a multi-part rim (5) having bead seats and lateral rim flanges (6), a tubeless pneumatic tyre (1), in particular a radical tyre, and also an emergency running system which is arranged on the rim between and in contact with the tyre beads (4) characterised in that the emergency running system is formed by two separate support rings (7,8) consisting at least in part of elastomeric material and by clamping and spreading segments (9) which engage in form-fitting manner between these support rings (7,8) and are braced by means of securing elements (10) against the base of the rim and the rim flanges (6) to provide a form-fitted, interengaging force transmitting assembly between the support rings (7,8), tyre beads (4) and rim (5). 2. A vehicle wheel in accordance with claim 1, characterised in that the inclination of the side surface of the annular disk-like support rings (7,8) facing the clamping and spreading segments (9) is substantially the same, at least in the region between the base of the rim and the level of the rim flanges, as the inclination of the outer surface of the clamping and spreading segments (9) which taper towards the base of the rim. 3. A vehicle wheel in accordance with claim 1 or claim 2, characterised in that the height of the emergency running system related to the base of the rim is approximately twice as large as the respective height of the rim flanges. 4. A vehicle wheel in accordance with claim 2, characterised in that the inclination of the side surface of the support rings (7,8) associated with the clamping and spreading segments (9) relative to the central radial plane amounts to 10 to 20 degrees, and in particular to approximately 15 degrees. 5. A vehicle wheel in accordance with one of the preceding claims, characterised in that the support rings (7,8) have a soft elastic sealing layer at the bead sides and/or at the rim base side. 6. A vehicle wheel in accordance with claim 5, characterised in that the sealing layer at the rim base side is extended in the form of a sealing lip (14) in each case up to the oppositely disposed support ring; and in that the sealing lips (14) of the two support rings (7,8) overlap each other. 7. A vehicle wheel in accordance with claim 5, characterised in that a sealing band which extends over the full rim width and which engages beneath the tyre beads (4) is provided for the seal at the rim base. 8. A vehicle wheel in accordance with one of the preceding claims, characterised in that sealing strips (21,22) which extends underneath the associated tyre beads (4) are formed on the support rings (7,8) for the seal at the rim base. 9. A vehicle wheel in accordance with one of the preceding claims, characterised in that the axial thickness of the support rings (7,8) which are preferably provided with cord and/or steel reinforcements, and of the clamping and spreading segments (9) respectively amount to approximately 1/3 of the mutual spacing of the beads (4) located on the beads seats. 10. A vehicle wheel in accordance with one or more of the preceding claims, characterised in that the clamping and spreading segments (9) which in the assembled state form a composite ring preferably have a smaller outer diameter than the support rings (7,8). 11. A vehicle wheel in accordance with any one of the preceding claims, characterised in that each clamping and spreading segment (9) has the shape of a truncated wedge; and in that the inner surface (12) associated with the truncated end is directly clamped in the assembled state against the base of the rim. 12. A vehicle wheel in accordance with any one or one of the preceding claims, characterised in that the outer peripheral surface (11) of the clamping and spreading segments (9) is provided with a gripping profile. 13. A vehicle wheel in accordance with any one or more of the preceding claims, characterised in that the inner surface (12) of the clamping and spreading segments (9) can be coupled with the base of the rim via interengaging projections and recesses. 14. A vehicle wheel in accordance with one of the preceding claims, characterised in that each clamping and spreading segment (9) is clamped against the rim (5) via at least one securing screw (10) which passes through the base of the rim and engages in a threaded bore (13) of the clamping and spreading segment (9). 15. A vehicle wheel in accordance with one of the preceding claims, characterised in that a securing screw (10) is simultaneously constructed as a valve for the supply of air to the tyre. 16. A vehicle wheel in accordance with one or more of the preceding claims, characterised in that lateral centering projections (15) are provided between the clamping and spreading segments (9) and the side surfaces of the support rings (7,8) which co-operate therewith on one of the two parts in the radially outer region, with the centering projections being intended to engage in guide groove (16) formed in the other respective part. 17. A vehicle wheel in accordance with any of the preceding claims, characterised in that the support rings (7,8) are provided with segments retaining projections (17) at the side facing the clamping and spreading segments (9) in the region of the outer periphery. 18. A vehicle wheel in accordance with one or more of the preceding claims, characterised in that the support rings (7,8) are provided with stiffness ribs (19) at the tyre wall side which in the assembled state come into contact with the inner wall of the tyre above the tyre beads (4).

Inventors: GEBERT, KARL, MISKA, KLAUS, OTT, ERNST
Applicants: SP REIFENWERKE GMBH
Application year: 1988
Main classification: B60B21
IPC codes: B60C17, B60C15, B60B21