GB2219557A

GB2219557A - A pneumatic vehicle tyre

Info

Publication number: GB2219557A
Application number: GB8908002A
Authority: GB
Inventors: Boris K P Nitsch
Original assignee: Uniroyal GmbH
Current assignee: Uniroyal GmbH
Priority date: 1988-04-26
Filing date: 1989-04-10
Publication date: 1989-12-13
Anticipated expiration: 2009-04-10
Also published as: GB2219557B; GB8908002D0; FR2630374B1; IT8920850V0; SE8901457D0; FR2630374A1; JPH0214901A; IT8920004A0; SE8901457L; IT1229094B; SE468163B; DE3813954A1

Description

r7 f) 19551 2 A PNEUMATIC VEHICLE-TYREE The invention relates to a

pneumatic vehicle tyre including a carcase with tyre beads, lateral walls and a reinforced, profiled tread strip.

Vehicle tyres produce noises when rolling on contact surfaces, since the edges of their profile elements, for example, are in contact with the rolling surface. Further more, vibrations of the air are produced within the tyre supporting face, which includes profile elements and free spaces, such as grooves, for example. The profile elements, the grooves and additional notches or recesses and the area surrounding the tyre are relevant for producing sound pressures, especially in the region of the convex portion ofthe toroidal body, the tyre, which is circumscribed by a convex encasing curve. These sound pressures are perceived as noise in the area surrounding the pneumatic vehicle tyre. The sound pressures can be measured. The emission of noise from vehicles, which includes the noise of tyres in particular, should be kept as low as possible.

Noises may be influenced more or less by the profiled configuration of the tyre. Numerous attempts have been made to reduce the noise of tyres, and listed among the number of proposals as to how this reduction should be achieved are, by way of example, US Patent Nos. 2272879 and 3023789, and German Offenlegungsschrift No. 2536470.

In particular, the profile dividing measures, that is to say the division of the profiling on the circumference of the tyre, are still a suitable means for reducing tyre noises.

However, the invention seeks to provide a suitable means for reducing the emission of noise which is not 2 - E dependent on the profiling and profile division, and at least a portion of the tyre surface in question, or the entire tyre surface in question, may be affected by such a reduction.

According to the invention, this object is achieved when at least a portion of the tyre surface, especially in the region of the tread surface, has an average surface roughness of 100 pm or more. Moreover, portions of the tread surface or the entire tread surface and/or additionally the tyre shoulders, or respectively the lateral walls of the tyre, may have the above-mentioned surface roughness.

The surface roughness preferably has peak-to-valley heights in the range of between 100 pm and 2000 pm. Such a consciously made, intentional, average roughness considerably reduces the level of sound pressures as compared with tyres with technically smooth surfaces, which have a relativelysmall peak-to-valley height. The effectiveness of the greater roughness, that is to say a plurality of microspaces between the peaks, results from diffused sound wave reflections an the relevant tyre faces.

Here, in particular, the volumes of the tyre surface can be mentioned which are affected by the encasing curve of the tyre and of the profile grooves, which volumes are enclosed or circumscribed in the respective supporting face. The effectiveness is provided by the sound absorption corresponding to the diffused sound wave reflection.

In addition, air which has entered between the rolling face and the tyre element can now es3ape more easily and, in consequence, contributes towards making a:

the tyre less noisy.

3 The roughness may be achieved by the roughness of the mould surface achieved during the production of the hot moulds. There is a distinction here between finished roughness and subsequent roughening as a result of blasting methods. However, the tyre may also be roughened. In such a case, blasting methods may be utilised, whereby peak-to-valley heights are produced as a result of sharp-edged roughening material being used.

This may be achieved by powdered glass blasting methods or by granulated glass blasting methods, by sandblasting methods, by microelectro methods or by similar methods.

The present invention will be further illustrated, by way of example, with reference to the accompanying drawing, in which:

Fig. 1 is a partial, cross-sectional view through a tyre; and Fig. 2 is an enlarged view of a roughened location.

The tyre 1 includes a carcase 3 having two tyre beads 4, lateral walls 5 and a profiled tread strip 6.

An encasing curve is referenced 7 and includes the region extending from one lateral wall to the opposite lateral wall via the tread surface. It extends substantially from the central cross-sectional height S of one tyre wall to the other tyre wall 10. It includes the tread, surface 8, the two tyre shoulders 9 and the wall regions 10.

This tyre surface is produced, for example, by air- blasting the hot mould and utilising sharp-edged blasting material, e.g. glass, and it is brought to a desired, average surface roughness of 300)jm, for example.

The peaks 11 and the valleys 12 can be seen in the detailed view of Fig. 2. Diffused sound wave reflections occur in the microspaces 13. When the profiled surface 8 is in contact with the rolling surface 2, sound is absorbed and, in consequence, the sound level is considerably reduced.

The peak-to-valley height is referenced R-r.

1

Claims

1. A pneumatic vehicle tyre, including a carcase with tyre beads, lateral walls and a reinforced, profiled tread strip, wherein at least one predetermined, but selectable portion of the tyre surface has a surface roughness of 100 pm or more in the region of the tread surface.

2. A pneumatic vehicle tyre as claimed in claim 1, wherein the entire tread surface has a surface roughness 1 C3 of more than 100 pm.

3. A pneumatic vehicle tyre-as claiM'ed in claim 1 or 2, wherein the surface of the tyre shoulders additionally has a surface roughness of more than 100 pm.

is

4. A pneumatic vehicle tyre as claimed in any of claims 1 to 3, wherein the upper lateral wall additionally has a surface roughness of more than 100 pm.

5. A pneumatic.vehicle tyre as claimed in claims 1 to 4, wherein the surface roughness has peak-to-valley heights of between 100pm and 2000 pm.

6. A pneumatic vehicle tyre, substantially as herein before described with reference to the accompanying drawing.

7. A method of producing a pneumatic vehicle tyre as claimed in claims 1 to 6, wherein the tyres are produced in hot moulds with a rough or roughened surface' of 100 jum or more.

8. A method of producing a pneumatic vehicle tyre as claimed in claims 1 to 6, wherein the tyres are subsequently treated by blasts of air and utilisation of sharp-edged blasting material.

g. A method of producing a pneumatic vehicle tyre as claimed in claim 7 or claim 8, substantially as hereinbefore described.

Pubhshed 1989 at The Patent Office, State House, 66'71 High Holborn. London WCIR 4TP. Furthe:, copies maybe obtained from The Patent Office. Sales Branch, St Maiy Cray, OrpingiDn, Kent BR5 3RD. Prmted by Multiplex techniques lid, St Mary Cray, Kent, Con. 1187