GB2073110A

GB2073110A - Pneumatic vehicle tyre

Info

Publication number: GB2073110A
Application number: GB8106944A
Authority: GB
Original assignee: Continental Gummi Werke AG
Current assignee: Continental AG
Priority date: 1980-03-07
Filing date: 1981-03-05
Publication date: 1981-10-14
Also published as: IT1135505B; GB2073110B; DE3008713C2; FR2477476B1; FR2477476A1; IT8119808A0; DE3008713A1

Abstract

A pneumatic vehicle tyre has a radial carcase, a crown reinforcing belt 6, e.g. of steel cord fabric, and an annular member 7 located radially outwardly of the belt and made of elastomeric material with a Shore A hardness of 40 to 50 degrees and a recoil elasticity (measured according to DIN 53 512) of 60 to 70, the width A of the member 7 being 60 to 70% of the width B of the belt 6. The member 7 may contain reinforcing filaments, e.g. of polyamide, at 90 DEG to the circumferential. The tyre tread comprises zig-zag circumferential grooves 5 bounding ribs 4 or rows of blocks. <IMAGE>

Description

SPECIFICATION Pneumatic vehicle tyre The invention relates to a pneumatic vehicle tyre, more especially for use by lorries, having a radial carcase and having a tension-resistant belt located between the tread strip and the carcase extending substantially over the width of the tread strip and having a circumferential belt or plate member of elastomeric material, especially rubber, located above this belt.

Pneumatic vehicle tyres are already known in which a plate member located between the belt and the tread surface, extends either over the whole width of the belt or forms narrow strips located at both belt edges, and is so comprised that it has a high absorbing action in order in this manner to effectively absorb vibrations and shocks in the region of the crown portion of the tyre.

It is an object of the invention on the other hand to reduce the rolling resistance of the tyre.

According to the present invention there is provided a pneumatic vehicle tyre having a radial carcase and a tension resistant belt located between the tread strip and the carcase and extending substantially over the width of the tread strip and a plate member located outwardly or above this belt and made of elastomeric material, characterised by the feature that the plate member has a Shore hardness of about 40 to 50 degrees Shore, a recoil elasticity of about 60 to 70, and has a width which corresponds substantially to 60 to 70% of the width of the belt.

Thus, the width of the plate is such that, with a tread surface profile having five or more circumferential strips forming the tread surface, it extends only over the region of the tread surface which is loc'ated between the edges of the tread strips forming the tread surface.

Further favourable properties of the invention are described in claims 3 to 15.

Owing to the high recoil elasticity or the relatively slight absorption a damping of the aforesaid plate member, significant heat developments in the region of the tread strip are eliminated or minimized, whereby a contribution is made towards a reduction of the roll resistance.

Added to this is the feature that the said plate member does not extend over the whole width of the belt, but only over its central section in such a manner that the shoulder portions of the tyre are substantially free of the aforesaid poorly absorbent elastomeric mixture. This extension of the plate prevents fissures and premature destruction in the region of the belt edges and especially in the base of the grooves which separate the tread strips located laterally outside from adjacent inwardly located tread surface strips. The development and the extension of width of the relatively soft plate member alone makes it possible for the plate to be used in the region of the tyre crown portion in a dynamically highly stressed zone of the tyre crown portion.

The invention will be described further by way of example, with reference to the accompanying drawings, in which: Fig. 1 is a radial fragmentary section through a pneumatic vehicle tyre for a lorry or goods vehicle, and Fig. 2 is a partial plan view of the tread surface of the tyre in accordance with Fig. 1.

A tyre body 1 formed generally of rubber or rubber-iike materials has a radially piy carcase 2 extending from one bead to the other and being anchored therein.

A tread strip 3 is formed by five zig-zag-shaped circumferential strips 4, 4' which may comprise a number of successive blocks.

The grooves located between the circumferential strips 4 are denoted by 5.

A peripherally tension-resistant belt 6 is provided between the circumferential tread strips 4 and the radial carcase 2 and belt 6 comprises, in conventional manner, two or more highly resistant cord fabric plies or webs preferably including steel, and which is able to produce side stabilisation of the belt and a bracing of the whole crown portion of the tyre.

The belt 6 has a thickness of about 4 to 6 mm and extends either side of the centre to substantially below the circumferential strips 4' forming the tread surface edges.

A rubber belt or plate member 7 having a wall thickness of 5 mm is provided binding directly on the belt 6 - the plate member being narrower than the belt 6. The width A of the plate member 7 thus only amounts to about 0.65 x B (width of belt).

The rubber mixture for the plate member 7 comprises the components listed below (K percentages).

Natural rubber 100 Plasticiser 5 Stearic acid 2 Zinc white (zinc oxide) 2.5 Anti-ageing agent 1 Inactive lamp black 1 5 Sulphur 3 Vulcanizing agent 0.8 Moreover, the plate member has a Shore hardness of 45 and a recoil elasticity of about 65.

The aforesaid width dimensioning of the plate member 7 results in the edges of the plate member 7 (seen from the centre of the tread strip) terminating short of the two grooves 5 located laterally outwards. Because of this arrangement there remains below the base of these grooves 5 a rubber mixture corresponding to the tread strip 3, so that the whole shoulder portion at 8 is accordingly comprised exclusively of the rubber mixture of the tread strip, the hardness of which mixture amounts to about 65 degrees Shore and the recoil elasticity (measured according to DIN 53 512) amounts to about 40.

The spacing of the base of the grooves 5 from the plate member 7 in the tread strip centre region is very slight, so that the centrally located circumferential strip 4 may accordingly rest substantially over its entire width exclusively on a cushion of low absorption or damping.

The circumferential strips 4 located adjacent the circumferential strips 4' are on the other hand located partly over the plate member 7 and consequently merge over a portion of their width into the rubber mixture which forms the tyre shoulders 8.

The plate member 7 may be reinforced although preferably does not contain any reinforcing members. In the event of highly stressed pneumatic tyres, these reinforcing members may be made as filaments or the like and thus extend at right angles to the circumferential direction of the tyre, so that the individual filament-like reinforcing plies, which are preferably selected to be such made of polyamide, are accordingly not mutually in contact and owing to their transverse extension cannot form a cross bracing.

Claims

1. A pneumatic vehicle tyre having a radial carcase and a tension resistant belt located between the tread strip and the carcase and extending substantially over the width of the tread strip and a plate member located outwardly or above this belt and made of elastomeric material, characterised by the feature that the plate member has a Shore hardness of about 40 to 50 degrees Shore, a recoil elasticity of about 60 to 70, and has a width which corresponds substantially to 60 to 70% of the width of the belt.

2. A tyre as claimed in claim 1, in which in a tread surface profile having five or more circumferential strips forming the tread surface, the plate extends only over the regions of the tread strips forming the edges of the tread surface.

3. A tyre as claimed in claim 2, in which the free edges of the plate member, seen from the centre of the tread surface, terminate short of the grooves which terminate the tread strips defining the tread surface edges towards the centre of the tread surface.

4. A tyre as claimed in claim 1, in which the recoil elasticity (measured according to DIN 53 512) amounts to about 65.

5. A tyre as claimed in claim 1, in which the hardness of the plate amounts to 45 degrees Shore A.

6. A tyre as claimed in claim 1, in which filament-like reinforcing members are embedded in the plate member and are located at right angles to the circumferential direction of the tyre.

7. A tyre as claimed in claim 6, in which the reinforcing members extend accurately at 900 to the circumferential extension of the tyre.

8. A tyre as claimed in claim 1, in which the thickness of the plate member is between about 30 and 40% of the cross section depth of the tread surface profiling.

9. A tyre as claimed in claim 8, in which the wall thickness is about 5 mm.

10. A tyre as claimed in any of claims 1 to 9, in which the plate member substantially passes through the vertical region between the outer surface of the belt and the base of the grooves forming the tread surface profiling.

1 A tyre as claimed in claim 10, in which the outer surface of the plate member substantially forms the base of the grooves of the tyre profiling forming the tread surface.

12. A tyre as claimed in claim 1, in which at least the tread surface strip is retained substantially exclusively by the plate member or is connected with this plate member.

13. A tyre as claimed in claims 1 and 12 in which a proportion of the circumferential strips are partly securely connected to the plate member, whilst with the remaining portion of their width they are securely connected to the outer surface of the belt.

14. A tyre as claimed in claim 13, in which said proportion of the circumferential strips are the tread strips located laterally adjacent to the tread strips forming the edges of the tread surface.

1 5. A tyre as claimed in claim 1, in which the width of the plate amounts to between 40 and 70% of the tread surface width.

1 6. A tyre as claimed in claim 6, in which the reinforcing members are made of polyamide.

1 7. A pneumatic vehicle tyre substantially as herein described with reference to and as illustrated in the accompanying drawings.