GB2202195A - A vehicle wheel and tyre assembly - Google Patents

Abstract

In a vehicle wheel (1) and pneumatic tyre (10) assembly the wheel has a rim (2) with wide flanges (3) and the tyre (10) has lateral wall regions (14) which, close to the beads (12), extend substantially parallel to the axis of rotation. In the operative state, the lateral wall regions (14) of the tyre (10) are supported on the wide flanges (3). The flanges (3) are each substantially as wide as half the opening width (A). The tyre is suitable for emergency running in its deflated state without the lateral wall regions contacting the ground. <IMAGE>

Description

A VEHICLE WHEEL The present invention relates to a vehicle wheel comprising a one-piece wheel rim which is provided with rim flanges axially spaced from one another, slightly tapering rim shoulders, at least one means for preventing the bead from slipping and a drop base, wherein each rim flange edge is adapted to be axially widened, and additionally comprising a pneumatic tyre which is provided with a carcase more especially a radial carcase and tyre beads which are axially spaced from one another and each contain a substantially inextensible bead core ring, the tyre beads being provided with a lower lateral wall region, which is bent axially outwardly, and lateral walls as well as a belt-reinforced, profiled tread strip, wherein the belt is substantially as wide as the tread surface, and wherein the lateral wall region close to the bead extends parallel, or almost parallel, to the axis of rotation.

Standard vehicle wheels comprise a standard drop base rim and a standard pneumatic tyre, such as are known, for example, according to ETRTE or the WdK (Motor Industry?; guideline. The rim is determined by the rim diameter and the opening width. The flange and rim shoulder have a predetermined, but selectable structural size. or this purpose, the pneumatic vehicle tyre is suitably adapted in respect of the configuration and disposition of the -carcase with its two tyre beads. The tyre beads, which are each provided with a substantially inextensible bead core, ensure a fixed, reliable seat on the rim. In the event of slight losses of compressed air, a locking means on the rin ensures that the tyre bead does not leave its seat. In the event of a considerable loss of air, this phenomenon is not guaranteed.It is then necessary to replace the vehicle wheel with a replacement wheel.

In the case of the known vehicle wheel which is claimed in German Auslegeschrift No. 33 389 71, for ensuring an emergency running facility and for dealing with normal driving conditions, the wheel rim and pneumatic tyre are adapted so that the rim has an emergency running support and the vehicle tyre is provided with a lateral tyre wall which extends outwardly in a flat manner. The carcase does not have any turning point and is connected to the bead without any transitional curvature. Instead of the provision of a drop base rim uith an emergency running support, an inclined shoulder rim may also be provided, whereby the tyre bead then has an eccentrically disposed bead core ring.

The known wheel rim has rim flanges in the form of an axially extended rim edge. The rim width thereby reaches the width of the tread surface. The emergency running facility is thereby ensured, but the possibility of the outwardly bent lateral tyre wall of the flat tyre touching the ground and sustaining damage is not positively eliminated.

In the case of a further known vehicle wheel which is claimed in German Auslegeschrift No. 29 37 272, a multipart wheel rim is in the form of a rim which substantially surrounds the tyre bead and has a groove, whereby the axially extended upper and lower rim edges form an opening in the form of an open mouth for the lateral tyre wall which extends axially in a flat manner.

The rim width reaches the width of the tread surface of the tyre. The possibility of the laterally curved lateral tyre wall of the flat tyre touching the ground and sustaining damage is not hereby conclusively eliminated.

In the case of a further known vehicle wheel which is claimed in German Auslegeschrift No. 24 32 927, the tyre rim is provided with an emergency running support, and the rim flanges are formed as axially extended flat rim edges. There are no mounting provisions when the rim is a one-piece construction. The vehicle wheel cannot be mounted without a drop base. It can be mounted when the rim is a multipart construction. Mounting the tyre is then a relatively complex and time-consuming operation. The rim width reaches the width of the tread surface. Under emergency running conditions, the tyre is centrally supported.

In the case of a further known vehicle wheel as claimed in United States Patent Specification No. 3930527, the wheel rim is in the form of a flat base and the rim flanges are in the form of axially widened flat edges. The rim may be provided with an emergency running support.

The rim width reaches the width of the tyre belt of a pneumatic vehicle tyre which has substantially standard dimensions. Under emergency running conditions, the laterally bent lateral wall will touch the ground and sustain damage.

Emergency running supports on rims for vehicle wheels are advantageous, but they have the disadvantage that the drop base is either restricted in width or totally filled. In consequence, the drop base is no longer a mounting aid. On the other hand,,the emergency running support increases the moving mass.

In a further known vehicle wheel as claimed in German Auslegeschrift No. 3000 428, the wheel rim is provided with radially internally disposed rim shoulders, and the correspondingly formed vehicle wheel has tyre beads which are mounted on the shoulders in a radially internally inverted manner. Such a vehicle wheel, which is provided with radially internal tyre beads, has a relatively large internal diameter and is suitable for emergency running.

The wheel is readily mountable according to a predetermined method. The width of the rim is smaller than the width of the tyre belt.

The manufacture of such a tyre is relatively disadvantageous because the tyre beads are adapted to be radially inwardly inverted. Both the known vehicle wheel of the standard type and the known safety vehicle wheel are capable of further improvement.

An object of the invention is to construct a vehicle wheel with the rim having a drop base and the rim flanges having wide edges, but without the provision of a central emergency running support, to secure the pneumatic tyre radially externally on the rim, according to the standard type, and to develop the wheel so that emergency running is possible and improvements in the general driving behaviour and rolling resistance are achieved.

The technical object of the invention resides in constructing the initially described vehicle wheel in such a manner that the rim width is equal to or greater than the tyre belt width, the tre cross-section is comparable with a low cross-sectional tyre, an advantageous, shortened diaphragm length and narrow diaphragm form of the flexible lateral type wall can be achieved, and the bead is reinforced by the lower lateral wall region.

According to the invention, this object is achieved in that the rim diameter is approximately 10% greater than the standard rim diameter, and each rim flange edge is half the width of the standard opening width, the tyre cross-section is less than 0.6 H/B, and the lateral wall region close to the bead is adapted to extend substantially parallel to the wide edge of the rim flange and, in consequence, is simultaneously adapted to extend parallel to the axis of rotation, whereby, in the operative state, the lateral wall region close to the bead is supported on the wide edge of the rim flange. The ratio of the cross-sectional height of the tyre relative to the crosssectional breadth of the tyre is denoted by H/B.

The proposed construction and arrangement of the rim and pneumatic tyre according to the invention permit, on the one hand, the rim width to be large and to be preferably larger than the tyre belt width and permit, on the other hand, the regions of the bead and lateral wall close to the bead to be relatively rigid and to be reliably and fixedly supported. The free diaphragm length of the flexible lateral wall is advantageously curved under loading.

The width of such a loaded tyre is equal to or slightly smaller than the width of the tyre in the unloaded state.

A relatively rigid wheel system is produced, which is fitted with a pneumatic tyre and comprises a rim, on the one hand, and a belt with a tread strip, on the other hand, whereby these wheel component parts, which are to be regarded as being fixed, are disposed relatively close to one another.

The flexible diaphragm of the curved lateral wall configuration is kept narrow, and the freedom of movement is restricted in this, respect. The curved lateral wall is directed radially inwardly. On the whole, advantages result therefrom in respect of a low rolling resistance and in respect of the general driving behaviour. This applies both to travelling in a straight line and to travelling round corners and results in improved roadholding.

Furthermore, reliable emergency running is ensured without the assistance of a central emergency running support. The supporting surface is provided by the wide edges on both sides of the rim flanges. These are generally cylindrical; that is to say, they extend parallel to the axis of rotation.

According to an additional feature of the invention, however, each rim flange edge may also taper slightly, more especially at an incline of 1 -3 relative to the axis of rotation In such a case, the lateral tyre wall close to the bead equally tapers slightly in a corresponding manner.

In addition, the lateral wall region close to the bead may have a separate bead protective strip, formed from hard rubber, on the side facing the rim. The frictional ratios are thereby enhanced. The depth of the drop base may be approximately 1.5 times deeper than the standard type.

Because the rim shoulders have a larger diameter, the vehicle wheel according to the invention has a rim clearance which is greater than that of the standard wheel and which is available for brakes of large dimensions. The new vehicle wheel is as wide as a vehicle wheel whose tyre beads are secured radially internally on the rim, and itis just as suitable for emergency running. However, the vehicle wheel according to the invention is relatively simple to manufacture since it is constructed, moulded and vulcanised according to conventional methods. In addition, the wheel is easy to assemble since the rim has a drop base.

The lateral wall region, which is close to the rim and is adapted to extend substantially parallel to the axis of rotation, is moulded and vulcanised according to standard methods. In terms of its function as a loaded wheel, the vehicle wheel according to the invention is comparable with a wheel having a low cross-sectional tyre of approximately 0.5 H/5. However, it is more stable because the rim width is large and is preferably wider than the belt width.

The present invention will be further illustrated, by way of example, with reference to the accompanying drawings, in which: Fig. 1 illustrates a vehicle wheel according to the invention which comprises a one-piece rim and a pneumatic tyre, the tyre being shown in sectional form; Fig. la shows a detail of the bead; Fig. 2 is a diagrammatic drawing of three comparable, but different tyres, namely a standard wheel, a safety wheel and a wheel according to the invention; rig. 3 shows operative drawings: a) of a standard wheel, b) of a safety wheel and c) of a wheel according to the invention; Fig. 4 shows a standard wheel of prior art in three operative states; Fig. 5 shows an additional wheel of prior art in three operative states; Fig. 6 shows a vehicle wheel according to the invention, which is fitted with a pneumatic tyre, in its pumped-up, unloaded state; Fig. 7 shows a vehicle wheel according to Fig. 6 in its loaded state; and Fig. 8 shows a wheel of Figs. 6 and 7 in its emergency running state.

The vehicle wheel 1 shown in Fig. 1 comprises a one-piece wheel rim 2 and a pneumatic tyre 10. The rim has two wide rim flanges 3 which extend axially in a flat manner, so-called wide-edged rim flanges. These can extend parallel to the axis of rotation or at a slight incline relative thereto. The rim shoulder is denoted by 5 and is adapted to slope slightly in accordance with the standard type. The drop base 7 communicates centrally internally with the rim shoulder.

A means 6 for preventing the bead from slipping is in the form of a nose-shaped raised portion (hump) and is provided between the drop base 7 and the rim shoulder. The wide edges of the rim flanges 3 are adapted to be axially externally rounded. This flange portion is denoted by 4.

The internal radius is denoted by 8, and the external radius is denoted by 9. The opening width A is a standard dimension. The width a of each wide edge of the rim flange amounts to A/2.

The rim width amounts to 2 x A. The rim diameter D is greater, by 7 to 15%, than the rim diameter of the standard type. The depth t of the drop base may be a standard dimension or may be deeper by up to t x 1.5.

The pneumatic tyre 10 comprises a carcase 11 having tyre beads 12 which are axially spaced from one another and each have a substantially inextensible bead core ring 13. The core ring is disposed centrally in the tyre bead. The bead is substantially formed according to the standard type, but at its radially outer end it communicates with a lateral wall region 14 close to the bead which extends substantially axially in a flat manner and extends substantially parallel to the axis of rotation (not shown). This lateral wall region is adapted to the wide edge of the rim flange 3. If the latter is slightly inclined,the lateral wall region 14 is also correspondingly inclined. The cross-sectional height of the tyre is denoted by H. The carcase 11 extends in a curved manner from the lateral wall region 14 to the region of the belt edge.

The lateral wall is denoted by 16. The tread strip 17 is reinforced by a belt-like embedded ply 18, more especially one formed from two steel fabric plies stacked one on top of the other. The carcase extends in this region 15 beneath the embedded ply 18 in a substantially flat-curved manner. The embedded ply 18 has a width substantially corresponding to the tread surface width L.

Fig. la shows a detail of a bead protective strip 19 in the bead 12.

Fig. 2 shows schematically, on the left-hand side of the tyre eOsS-Sectien, the eanfiguPations of 8 rim 20 and a standard tyre 21, a 4 B 14 rim and a 145 R 14 tyre being provided by way of example. The opening width A amounts to 102 mm, and the rim diameter D amounts to 355 mm.

The left-hand side of the tyre cross-section additionally shows the configurations of a CTS rim 22 and a CTS tyre 23, a CTS 185/45R425 tyre being provided by way of example, the rim diameter D amounting to 425 mm and the opening width A amounting to 120 mm. The width of the tyre belt G amounts to 160 mm. The tyre has an outer diameter P of 590 mm.

The right-hand side of the tyre cross-section illustrates the configurations of a rim 24 and a pneumatic tyre 25 according to the invention The rim diameter D amounts to 395 mm here, and the opening width amounts to 102 mm in accordance with the standard type.

The bottom of the drop base is substantially on a level with the tyre shoulder of a standard tyre. The axially widened wide edge a of the rim flange is approximately 58-60 mm wide.

The outer dimension of each rim flange is axially greater by approximately 10 mm because of the curvature 4 The outer diameter P of the tyre amounts to 590 mm.

The size of such a tyre according to the invention is denoted by 195/50 R 395, 195 being the tyre breadth, 50 being the H/B ratio, and R 395 being a radial tyre with a rim diameter of 395 mm. The larger width of the rim compared with the width of the belt is apparent here.

Fig. 3 shows schematically the differences betueen the various wheel systems, namely the standard radial tyre a), the CTS tyre with radially internally mounted tyre beads b) and the tyre according to the invention c).

System a) includes a standard rim and a standard radial tyre. The width of the rim, which is to be regarded as being rigid, is denoted by U2 and the width of the metal belt, which is to be regarded as being rigid, is denoted by U1. In this system U1 is substantially equal to U2, since the belt width substantially amounts to 0.7 of the cross-sectional breadth of the tyre. The flexible parts of the lateral tyre wall are respectively formed from portions of the carcase and lateral wall.

Such a tyre is not suitable for emergency running.

System b) includes a CTS rim and a CTS tyre. In this case, the width of the rim W2 which is to be regarded as being rigid, amounts to at least 0.75 of the width of the belt W1. The flexible parts of the carcase and lateral wall are of a bulged form, since the tyre beads are mounted radially internally on the rim. Such a wheel system is suitable for emergency running. In such a case, the lateral wall may become deformed more easily than a lateral tyre wall of the standard type. However, the CTS tyre is not as advantageous in respect of manufacture.

System c) includes a rim and a tyre according to the invention. In this case, the width of the rim W2, which is to be regarded as being rigid, is at least equal to, but is generally greater than the width W1 of the belt, which is to be regarded as being rigid. The flexible lateral walls are shorter than those of systems a) and b).

The flexible lateral wall region is influenced by the connection with the relatively rigid and supported lateral wall region close to the bead and bulges radially inwardly under loading.

The rim and tyre do not differ considerably from the standard type. Because of the drop base, the tyre can be readily mounted. The tyre is moulded and vulcanised in known, twin-chambered or segmental moulds.

The wheel can be used for emergency running. In such a case, the rubber parts of the inner lateral wall are substantially supported on the parts of the lateral wall regions close to the bead. If necessary, it is possible for the lateral wall region, which rests on the wide edge of the rim flange, to be provided with friction-reducing means. In the loaded state, the cross-sectional breadth of the tyre according to the invention is substantially equal to the cross-sectional breadth of the unloaded tyre. For this reason, and because the wide regionssof the rim and tyre belt, which are to be regarded as being fixed, are disposed relatively close to one another, system c) is more stable than system a) or b) and, in consequence, the rolling resistance is advantageous and the general travelling behaviour is improved by comparison with known vehicle wheels.

Fig. 4 shows the vehicle wheel 20, 21 of Fig. 2, which is fitted with a pneumatic tyre and corresponds to the standard type, in its pumped-up, unloaded state, under load and in the emergency running state.

The cross-sectional breadth in the pumped-up,unloaded and loaded state 21' is substantially identical. In the emergency running case, the lateral wall 21" bulges laterally and touches the ground with the outer flank and thereby becomes damaged.

Fig. 5 shows the vehicle wheel 22, 23 of Fig. 2, which is fitted with a pneumatic tyre and corresponds to the CTS system, in the pumped-up, unloaded state, under load and in the emergency running state. The crosssectional breadth of the pumped-up, unloaded and loaded state 23' is substantially identical. In the emergency running case, the lateral wall 23" extends outwardly, but it does not touch the ground. The inner surface is supported on the outside of the rim shoulder.

Figs. 6, 7 and B show the vehicle wheel 24, 25 of Fig. 2, which is fitted with a pneumatic tyre and corresponds to the embodiment of the invention. The cross-sectional breadth of the pumped-up, loaded tyre 25' cf.Fig. 7, is somewhat smaller than the cross-sectional breadth of the pumped-up unloaded tyre 25,'of. Fig. 6.

The entire width of the relatively rigid belt is smaller than the width of the wide edged rim. Furthermore, the lateral wall region close to the bead is relatively rigid because it extends substantially parallel to the axis of rotation and is supported on the wide-edged rim.

In consequence, this part of the lateral wall may be included in the relatively rigid system of the wheel.

Because the rigid parts of the belt, on the one hand, and of the rim, on the other hand, are disposed relatively close to one another, the flexible part of each lateral sall is relatively short. In addition, the flexible portion is influenced by the connection with the lateral wall region close to the bead. Under loading, this flexible portion bulges laterally and is inclined to become deformed radially inwardly. Uhen viewed collectively, these differences of the new vehicle wheel present advantages which reduce the rolling resistance and improve the general travelling behaviour of the wheel fitted with a pneumatic tyre.

In the emergency running case, cf. Fig. 8, the flexible lateral wall portion 25 bulges further radially inwardly and, in this respect, does not touch the ground.

The inner surface of the tyre is thereby supported on the lateral wall regions close to the bead. In consequence, the vehicle wheel is also suitable for emergency running without the provision of a central emergency running support.

Claims (6)

1. A vehicle wheel comprising a one-piece wheel rim which is provided with rim flanges axially spaced from one another, slightly tapering rim shoulders, at least one means for preventing the bead from slipping and a drop base, wherein each rim flange edge is adapted to be axially widened, and additionally comprising a pneumatic tyre, which is provided with a carcase and tyre beads which are axially spaced from one another and each contain a substantially inextensible bead core ring, the tyre beads being provided with a lower lateral wall region, which is bent axially outwardly, and lateral walls as well as a beltreinforced, profiled tread strip, wherein the belt is substantially as wide as the tread surface, and wherein the lateral wall region close to the bead extends parallel, or almost parallel, to the axis of rotation, wherein the rim diameter is approximately 10% greater than the standard rim diameter, and each rim flange is as wide as the wide-edged flange with approximately half the standard opening width, and wherein the pneumatic tyre has a tyre cross-section which is less than 0.6 H/B, and the lateral wall region close to the bead is adapted to extend parallel to the wide edge of the rim flange, this lateral wall region being disposed so as to be supported on the wide edge of the rim flange, and the H/B equation signifies the ratio of the cross-sectional height H of the tyre relative to the cross-sectional breadth B of the tyre.

2. A vehicle wheel as claimed in claim 1, wherein the rim flange edge tapers slightly relative to the axis of rotation, and the lateral wall region close to the bead tapers slightly accordingly.

3. A vehicle wheel as claimed in claim 2 in which the rim flange edge tapers by 1 - 30.

4. A vehicle wheel as claimed in claim 1, 2 or 3 wherein the lateral wall region close to the bead has a bead protective strip formed from hard rubber.

5. A vehicle wheel as claimed in any preceding claim, wherein the depth of the drop base of the rim is approximately 1.5 times deeper than the standard drop base.

6. A vehicle wheel, substantially as hereinbefore described with reference to Figs. 1, la, 2, 3c and 6, 7 and 8 of the accompanying drawings.