LU82895A1 - IMPROVEMENTS IN TIRE TRUCKS, TIRES AND THEIR MANUFACTURE - Google Patents

Description

at:

"INVENTIVE COATINGS - KT DRAWINGS INDUSTRIAL MODELS - MANUFACTURING BRANDS

OFFICE KIRKPATRICK

G, C. L. PLUCKKR * ™ FOUNDED IN 1852 - *

INDUSTRIAL PROPERTY ADVICE

SQTTAHE DE MEEÛS «- 1040 BRUSSELS

DESCRIPTIVE MEMORY

FILED IN SUPPORT OF A REQUEST FOR

PATENT

* »

FORMED BY

DUNLOP LIMITED for

Improvements to tire treads, tires and their manufacture.

The present invention relates to tire treads *, tires and their manufacture.

Tire treads can be molded and vulcanized in one piece with a tire carcass to form a complete tire, or they can be shaped separately from the carcass and subsequently attached to form a complete tire. A separately shaped tread can take the form of a tread tape into which this tread is to be incorporated, the ends of the tread tape being joined when this tread tape is placed on the carcass for making the tire. Separately shaped treads can be applied to new carcasses or to old tire carcasses from which the original tread has been removed.

Classic tire treads have a complicated and precise pattern of ribs and blocks forming a network of surface tread patterns that allow a classic tire to roll over a wet paved surface without excessive water buildup between the tread and the paved surface. Such an accumulation of water can seriously reduce the grip of the tire on the paved surface and thus cause a dangerous reduction in braking capacity and maneuverability. These conventional tire treads require complicated and expensive molds to shape the pattern of the tread patterns.

The invention provides a new form of tire tread and a tire comprising this new tread (as well as methods of making the tread and the tire) which makes it possible to consider otherwise the maintenance of a good adhesion on a wet paved surface and which simplifies the molding of the tread, which leads to economic advantages.

According to a first aspect of the invention, there is provided a tire tread made of an elastomeric material and comprising a contact surface with the ground which is substantially smooth and provided with a number of separate openings. 'sinking into the tread from said surface and communicating with at least one water evacuation passage inside the tread.

Said at least single water discharge passage is preferably arranged circumferentially in the tread.

The tread preferably contains several water drainage passages which can or can be connected to each other inside the tread! of rolling. Said water discharge passages may be aligned in the circumferential direction or in the direction *, transverse in the tread or at any suitable intermediate angle or have any combination of such alignments. . The water evacuation passages can form a rectilinear or rombombic network of intercommunicating passages, or a dendritic network of passages.

When the tread is part of a tire, the only communication of the water evacuation passage or each of them with the outside of the tire preferably passes through the openings, but the passage or at least some of the passages may or may further open to the outside of the tire in the region of its shoulders outside the surface of the tread normally in contact with; the ground and preferably near said contact surface with the ground.

The surface of contact with the ground of the tread may be provided with one or more continuous or discontinuous grooves which are preferably in circumferential sub ~ stance and which preferably do not directly intersect any evacuation passage of water, but may intersect one or more of the openings, or, alternatively, the alignment and dimensions of the groove (s) in combination with the dimensions and arrangements of the openings may be such that no groove intersects any opening or any opening party. No circumferential groove preferably has direct or indirect communication in the tread with any evacuation passage.

The separate openings are entirely bounded by tread material (and are not, for example, open slits which extend to the edges of the tread) and are preferably distributed in the circumferential direction in the tread of = such that the contact surface with the ground of the tread comprises continuous strips of tread material which extend transversely or at an angle preferably not exceeding ^ 0 ° with respect to in the transverse direction, over the entire width of the surface in contact with the ground, the continuity of the blades being interrupted only by the groove or grooves, if any.

The tread can be formed with a first radially external part which extends radially inwards from the surface in contact with the ground, and with a second radially internal part offset more radially inwards. of the tread as the radially external part, the first radially external part containing only the openings and the groove or grooves, and the second radially internal part containing only the water evacuation passage or passages as well as the radially inner extreme parts of the groove or grooves, if they are deeper than the radial dimension of the radially outer part of the tread. The combined volume of the openings in the radially external part of the tread can be between 5 and 65% of the total volume of the radially external part and is preferably between 10 and 50%. The combined volume of the water evacuation passage (s) in the radially internal part of the rolling heath can be between 10 and 70% of the total volume of the radially internal part and is preferably between 15 and 55% ·

The openings can have any suitable cross section and can, for example, be circular, elliptical, triangular, square, rectangular, trapezoidal, rhombic or have any suitable combination of different shapes. The openings preferably have individual cross sections not less than 9 mm.

The water drainage passage (s) may have any suitable cross section and any cross-sectional dimension which guarantee the adequate passage of water when the tread, as part of a tire , is in service at a specified speed on a surface covered with a film of water of a specified thickness. The region of the tread in contact with the ground at a given moment is compressed under the weight of the vehicle as well as under the dynamic load due, for example, to the unevenness of the ground. It is desirable that the water discharge passage (s) are not completely closed by this compression and it is also preferable that the water evacuation capacity of the passage (s) is not excessively reduced by this compression. However, the preferred cross section of a water discharge passage is a square or rectangular section or any other section tending to remain open when compressed, and the preferred minimum dimension is 2 mm in a radial direction relative to the tread.

According to a second aspect of the invention, a tire is provided, preferably a tire, comprising a carcass and a tire tread according to the first aspect of the invention. The tire may be a radial tire comprising a tread reinforcement sub-protector disposed between the carcass and the tread, or it may be a cross-ply tire or a belt tire bias comprising a tread reinforcement sub-protector disposed between the carcass and the tread.

The tread can be molded in a block with the rest of the tire, for example using soluble, fusible, destructible or removable cores to form the openings and the passages of the tread, or, as a variant, the tread can be shaped independently of the carcass, for example in the form of a ribbon or a band, the ribbon being united or subsequently fixed to the carcass by any suitable process to form a complete tire and the band being an endless tread loop for use with tire carcasses designed to receive replaceable treads attached to the carcass by keying and / or friction.

(The first aspect of the invention comprises a tire tread which is either an element forming an integral part of a tire, or an element separate from a tire, for example in the form of a tread tape or a band).

The tire according to the second aspect of the invention may be formed by a carcass on which the radially internal part of the tread (containing the water drainage passage (s)) is molded in one piece and by a radially external part of the separately formed tread (containing the openings) which is subsequently united or fixed to the carcass over the radially internal part, the openings coinciding with the passage or passages to form the complete whole of the carcass and tread.

According to a third aspect of the invention, there is provided a method for manufacturing the tread of the tire according to the first aspect of the invention, which consists in molding a tread tape in an elastomeric material in a mold internally shaped and dimensioned substantially in accordance with the final shape required of the tread tape. This process can include an additional phase: ’consisting in partially or vulcanizing: completely the tread tape while it | found in the mold or after it has been removed from the mold.

According to a fourth aspect of the invention, there is provided a method for manufacturing the tread of a tire according to the first aspect of the invention in which the water evacuation passage or each of them must be arranged in the circumferential direction in the completed tread, which consists in extruding an elastomeric material by a die, the orifice of which has a cross section substantially equal to the cross section of a tread strip without opening, then drilling, punching or otherwise forming the required openings before, after or at the same time as cutting the extruded tread into strips of the required length. The extrusion orifice may have a section capable of forming one or more circumferential grooves in the tread when it is extruded. The extruded tread can be partially or completely vulcanized before or after its sectioning into ribbons of the required length, vulcanization being a continuous or batch process.

According to a fifth aspect of the invention, there is provided a method of manufacturing a tire which consists in: i) preparing a tread tape according to the first aspect of the invention; ii) coating a vulcanized or vulcanized tire carcass with a solution for a standard vulcanizable tread with cbaud; iii) attach to the tire carcass, for example by means of a conventional rubber solution, a layer of standard sub-tread based on natural rubber; iv) apply the tread tape to the carcass and join the ends of the tape, and: v) wrap the tire with a strip of vulcanized rubber and vulcanize the whole, for example with steam.

In the method described above in which a vulcanized tire carcass is used, this carcass can be prepared, for example, by grating before being coated.

Another method of constructing a tire in accordance with the invention consists in: i) building a vulcanized tire carcass by an adequate method so that it has a raised circumferential strip at each shoulder region; ii) forming a tread tape according to the invention (for example by extrusion) and joining the ends to form a tread ring; iii) insert the tread ring between the shoulders on the carcass.

When the resulting tire is inflated to an appropriate wheel rim, air pressure keeps the tread ring in place. You can easily renew the tread tape by deflating the tire, replacing the ring with a new one and re-inflating the tire. If desired, inextensible circumferential reinforcements can be provided in the rubber blades between the passages. Examples of this method of construction are described in English Patent No. 755 * 990.

It is estimated that the passages in the treads of the tires in accordance with the invention behave like evacuation paths passing through the openings starting from the contact surface with the ground of the tread, but the invention should not not be considered to be limited by this theory. The water which enters the openings can simply be retained there until this part of the tread deviates by rotation from the contact with the ground, the water then being ejected by the centrifugal force produced. Alternatively or additionally, water can enter and exit through different openings after being transferred to the interior of the tread by the water discharge passage (s).

Embodiments of the invention will be described below, by way of example only, with reference to the accompanying schematic drawings, in which: Eig. 1 is a plan view of part of the external surface of the tread of a tire; the Eig. 2 is a view in radial section of the region of the tread of the tire along line II-II of the Eig. 1; the Eig. 3, H- and 5 are plan views of parts of treads having patterns of openings and intercommunicating water discharge passages different from that shown in FIG. 2; Fig. 6 is a radial sectional view of the tread portion along the line VV in Fig. 5; Fig. 7 is a perspective view of a tread ring intended to be attached to a suitable carcass ; Fig. 8 is a radial sectional view of the tread ring of Fig. 7 mounted on a tire carcass; Fig. 9 is a plan view of part of another form of tread; Fig. 10 is a cross-sectional view along line XX of Fig. 9; Fig. 11 is a cross-sectional view along line XI-XI of Fig. 9, and Fig. 12 is a cross-sectional view (corresponding to FIG. 11) of a variant of the tread of FIG. 9-

As shown in Figs. 1 and 2, a tire carcass 17 is provided with an elastomeric tread 11.

The tread 11 has a substantially smooth contact surface with the ground 18 having cylindrical openings 13 which open across the surface in a intercommunicating and rectilinear network of water drainage passages 1 * + which open into the shoulders 12 at the outlet orifices 15- End of service, the surface water in the area of contact of the tire with the ground enters the openings 13, then passes circumferentially along the passages l * + a and / or laterally along the passages l * fb in order to be ejected through the outlet orifices 15 in the shoulders 12. It should be noted that the surface in contact with the ground 18 has blades of tread material on the ground continuous transverse between transverse rows of successive openings 13 in the circumferential direction.

Fig. 3 illustrates a tread strip 31 comprising cylindrical openings 33 which open in a straight rhombic network or aligned diagonally with intercommunicating water discharge passages 3 ^ which cut across the shoulder regions 32 at outlet ports 35 · As in the case of the tread of Figs. 1 and 2, the contact surface with the ground 38 is substantially smooth and has continuous transverse blades of tread material between transverse rows of openings 33 ·

Fig. is a plan view of a tread tape corresponding to the geometrically similar treads of Figs. 1 and 3 · The tread tape * fl has a rhombic network of intercommunicating water evacuation passages inside the tread, this network consisting of transverse passages communicating with passages aligned approximately under a angle of 30 ° to the circumferential direction of the tread. At the intersections of these transverse passages bb and aligned at an angle, the tread strip bl is provided with openings ^ 3 which have a rhombic section corresponding to these intersections as to their dimensions and their alignments. The passages communicate with the outside of the tread at the openings b $ in the shoulder regions b2. adjacent to the surface in contact with the ground ^ 8, but external to this one.

Another embodiment of the tire tread according to the invention is illustrated in plan in FIG. 5 and in section in FIG. 6. This embodiment / nur λττ π / ι η η n RP ROOfi comprises a "tread strip 5l comprising several (in this case seven by way of example only) water drainage passages 5 * + below the tread which are aligned in the circumferential direction inside the tread, which are not intercommunicating and which are not connected to the shoulder regions 52 of the tread due the absence of any transverse passage. The passages 5 ^ communicate with the surface in contact with the ground 58 of the tread band 51 by means of openings 53 arranged in a regular manner, the cross sections of these openings being substantially square and slightly larger than the width of the passages 5 ^ · Due to the transverse alignment of the openings 53j the contact surface with the ground 58 has blades of transverse and continuous material, but, if desired, the openings 53 in from s adjacent circumferential columns can be staggered or offset in the circumferential direction so that these continuous strips of material are not only transverse, but are aligned at a certain predetermined angle.

The Pig. 7 is a perspective view of an embodiment of a tread in the form of a strip 71 or of an endless loop of ribbon according to the invention.

The strip 71 is similar but not identical to the strip 51 of FIGS. 5 and 6 in the sense that, while it is provided with several non-communicating water evacuation passages 7 ^ and aligned in the circumferential direction, the openings 73 are of circular or elliptical section. Fig. 8 illustrates a cross-sectional view of the strip 71 of FIG. 7 in service as a replaceable tread on a tire carcass 87 which is provided for this purpose with a peripheral recess 80 dimensioned to receive the hande 71 · The carcass 87 comprises a radial or other suitable reinforcing ply 86 and the strip 71 preferably includes inextensible circumferential reinforcements 79 embedded in blades 78 formed between the circumferential passages 7 * + internal of the strip 71 (that is to say the main surface opposite the surface in contact with the ground 78), as well as the peripheral counterpart surface of the carcass 87 may be provided with a complementary system of ribs and grooves (not shown) constituting a keying system capable of increasing the friction and the relative adhesion between the strip 71 and the carcass 87 when the latter is inflated.

Figs. 9ü 1 ° and 11 illustrate yet another embodiment of the tread tape 91 according to the invention, this embodiment being similar to that of FIGS. 5 and 6, but being simplified in detail compared to all of the embodiments described above insofar as the water discharge passages 9 ^ extend only in the circumferential direction and have the same lateral width that the openings 9 * + · These features are clearly shown in Figs. 10 and 11 and it should be noted that the constant section of the tread tape easily allows manufacture by extrusion, while the equal widths of the openings and passages simplify the punching or the size of the openings in the extruded part.

Fig. 12 illustrates a variant of the previous embodiment (in particular as shown in the corresponding Fig. Il.) In which the tread tape has a central circumferential groove 120 and two lateral circumferential grooves 122. The grooves 120 and 122 can be easily formed by the extrusion die (if used), and can be used in the tread, if desired, for example to provide directional stability to a tire- Although three circumferential grooves are shown in FIG. 12 by way of example, other arrangements of circumferential grooves can be used, such as for example a single central groove or a single lateral groove or else several lateral grooves without a central groove or any arrangement of transverse or oblique grooves (not shown) which are added to or replace one or more circumferential grooves. Fig. 12 illustrates a preferred arrangement in which no circumferential groove intersects any opening 93 or any water discharge passage 9 ^, but the invention contemplates using one or more circumferential or non-circumferential grooves which intersect one or more steps -I wise evacuation of water and / or one or more openings so as to establish direct communication inside the tread between one or more grooves of this kind and the passage (s) and / or openings, which is contrary to the preferred arrangement in which there is no such intersection or direct communication inside the tread.

The embodiment of the tire tread shown in FIG. 12 can be envisaged in a first and a second part 126 and 127, respectively. The first part 126 of the tread is radially external when the tread is part of a tire and extends radially inwards from the surface in contact with the ground 128 which is normally the radially external part of a tire when the tread is part of the tire. The surface in contact with the ground 128 has blades of tread material on the ground which are transversely continuous between rows of openings 93 with the exception of the circumferential grooves 120 and 122. The second part of tread 127 is offset radially inward of a tire more than the first radially outer tread portion 126 and extends radially inward from the first tread portion 126 to the same extent as the radially outer portion more internal of the water discharge passages 9 ^ which intersect the radially innermost surface of the tread in the embodiment shown in FIG. 12, but which should not do so because these passages could, in a variant, be in the form of tubes or other completely closed passages inside the tread.

The first tread portion 126 contains only the openings 93 and the circumferential grooves 120 and 122. The second tread portion 127 contains only the water discharge passages 9 ^ -, as shown in the Fig. 12, but the second part 127 could also include radially innermost parts of circumferential grooves or the like if these grooves were deeper than the intersection of the openings and passages.

Although circumferential grooves are shown by way of example only in FIG. 12, any other embodiment of the invention among those shown, for example, in Figs. 1 to 11, can also be provided with one or more continuous or discontinuous grooves aligned so as to be circumferential or substantially circumferential or to present any other desired alignment.

The invention is illustrated in more detail by the following examples.

EXAMPLE 1.-

Qn manufactures a l55SR 13 radial ply tire with a tread in substance as described and shown in FIG. * + as follows.

The original tread of a 155 & K 13 tire is removed from the grinding wheel so that the crown is as level as possible without damaging the under-guard. The surface is then coated with two layers of a suitable rubber solution which is left to dry. A layer of vulcanizable rubber material of the type known as a "tread sub-band" measuring 1 mm x 110 mm is applied to the crown of the tire.

A tread tape having a pattern of openings and water drainage passages as shown in FIG. so that its length is slightly greater than the circumference of the tire. During the molding process, the outlet holes hÿ of the passageways kk passing through the shoulder \ 2 of the tire tread are covered with a molding cap.

Apply a suitable rubber solution to the underside of the tread tape and allow it to dry. The tread tape is then placed precisely around the crown of the tire, the coated or coated side being adjacent to the tread sub-strip. Or cut the ends and put them together, then stretch a strip of vulcanized rubber around the whole. The tire is then subjected to steam heating to vulcanize the vulcanized rubber parts and thus assemble all the parts of the tire. The tread of the resulting tire is essentially as shown in FIG. of the accompanying drawings, except that the outlet orifices 5 of the passages are closed by a molding cover, the specifications being as follows.

Total width, including shoulders (^ 2) 105 mm

Width of each passage (Mf) 5.2 mm

Depth of each passage (Mf) 3 mm

Dimensions in cross section of each opening (¾) 5.2 x mm

Distance between openings (^ 3) 1) laterally 3.6 mm 2) circumferentially 3.2 mm

Ratio of the secti on% total transverse of the openings (V3) the total surface of the tread 35%

Tread rubber hardness 70 ° Shore A

EXAMPLES 2 AND 3.-

Qn repeats Example 1, except that the rubber of the tread has hardnesses of 83 ° Shore A and ^ 0 ° Shore A respectively.

The tires produced in examples 1, 2 and 3 are each subjected to tests aimed at determining the noise produced, the grip on wet roads and the degree of overheating. When these tests have been carried out, the molding cover which covers the outlet openings of the passages is removed in view of Examples 5 and 6, respectively. These tires are then subjected to the same series of three tests.

RESULTS

The noise produced is significantly reduced for all examples compared to the noise produced by an SP tire (tread rubber with a Shore A hardness of 70 °) · The improvement in grip on wet roads is remarkable at point d be amazing for all the examples compared to an SP * f tire.

Thermograms for each of the dry tires of Examples 1 to 6 indicate an accumulation of heat at uniform low temperature over the entire surface of the tread without localized high temperature characteristic of standard tires.

Due to the absence of blocks and grooves in the tread of the tire according to the invention, one or more of the following properties can be obtained if desired: 1) the backflow of water from the the contact surface between the tire and the ground is improved and the accumulation of hydraulic pressure (the main cause of aqua-planing) at high speeds is greatly reduced5 2) the ability of the tread to adapt to the roughness of the roadway is improved; 3) the ventilation of the tread and the under-protector is improved, which, together with the absence of large blocks of tread rubber, gives a lower and more uniform operating temperature; * 0 grip on wet roads is less affected by tire wear; 5) the noise produced is greatly reduced; 6) due to improved grip on dry and wet roads and lower operating temperatures, there is more freedom in the design and formulation of the composition of "tread to obtain a tire more resistant to wear and / or lighter ETFMPLE 7.-

An 8.25 Rl6 radial ply truck tire is produced with a tread in substance as described and shown in Eig. 9, 10 and 11.

The original tread of an 8.25 El6 tire is eliminated with the rasp, leaving the crown substantially flat and without damaging the under-protector. The surface is coated with two layers of a suitable rubber solution and allowed to dry.

A tread tape is molded as shown in the idg. 9 so that it is slightly larger than the circumference of the tire. It is then cut to a length slightly greater than the circumference of the tire along the middle of the appropriate transverse blades, the underside is lightly polished to expose a clean and fresh surface, the cut ends and the underside of the longitudinal blades are coated with a solution rubber that is left to dry. A thin layer (1.5 mm) of unvulcanized tread composition is applied to one of the cut ends.

The tread tape is then applied to the grated carcass as described in Example 1 and is made to adhere to it using the vulcanization process for retreading; standard "Duraband" page.

The specifications of the tread tape are as follows.

Total width l60 mm

Opening dimensions: transverse 9.5 mm circumferential 17.0 mm depth 11.0 mm

Longitudinal blade widths: shoulder l8.75 mm others 13.1 mm

Depth of longitudinal blades 5, ° mm Repeat pattern 25.0 mm

Unworn tread opening report $ 25

Hardness of tread rubbers 70 ° Shore A

Machine tests of the tire of Example 7 compared to a "Duraband" retread tire with a standard production tread pattern SP 111 are as follows.

(Note: the standard SP 111 tire has the same tread rubber composition as that of Example 7 and these two tires differ only in the patterns of their treads).

1. Transverse cornering reaction on wet pavement

Machine producing a high speed transverse cornering reaction

Road load 1,000 kg

Machine load $ 90 of road load p

Pressures * f, 0, 6, 5 kg / cm

Rim 6.5 x 16

Skid angles -lA °, 0 to 6 °, right turn

Speeds 16 to 1M + km per hour

Sand and shells surface Water flow 1.0 and 7.5 liters / second.

Results Example 7 and the standard tire SP 111 are comparable for skid angles up to 1 °, but not after, the tire of example 7 is increasingly higher, especially at higher speeds for the two flow rates. of water.

2. Transverse cornering reaction on dry pavement

Machine producing a transverse cornering reaction at high speed.

Conditions similar to those of the wet road test, except that the surface is dry.

Results

No significant difference between the tire of Example 7 and the standard SP 111 tire.

3 · Braking on wet roads

Machine producing a transverse turn reaction at. great speed.

Conditions similar to those of tests on wet pavement, water flow 7 * 5 liters / second.

Results

Coefficient% of drift - Coefficient of tip slip stroke

Example 7 0.168 50 0.120 SP 111 0.136 70 0.100 k ·. Distribution of contact pressure and stresses in the ground plane Load 1,800 kg 2

Pressure 6.75 kg / cm Results Very appreciable reduction of the stresses in the ground plane in the lateral direction with the tire of example 7 compared to the tire SP 111.

Although various shapes and sizes of treads and tires have been described above by way of example, the invention is not limited thereto and other shapes and sizes of treads and tires may be used. developed by a specialist without departing from the scope of the invention. The treads and tires according to the invention can be manufactured by the processes defined here or by any other suitable process.

Claims (26)

1. Tire tread made of elastomeric material, characterized in that the surface in contact with the ground (18, 38, H-8, 58, 78} 128) is substantially smooth and is provided with a large number of separate openings (13, 33d * + 3, 53, 73, 93) which sink into the tread (il, 31, * tl, 5l, 71, 91) from said surface ( 18, 38, * f8, 58, 78, 128) in order to communicate with at least one water drainage passage (l ^ a, l ^ b, 3k, kk, $ k, 7k, 9 * 0 to l inside the tread. 2. Tire tread according to claim 1, characterized in that at least one water evacuation passage (kk, 7k, 9 ^) is arranged circumferentially inside the tread (5l, 71, 91). 3 · - tire tread according to claim 1, characterized in that it (it, 31, * EL, 5l, 71, 9l) contains several water drainage passages (l ^ a, lVb, 3k , Mf, 5 * f, 7k, 9k). k.- Tire tread according to claim 3, characterized in that the various water discharge passages (l ^ a, iVb, 3 * f, Mf) are connected to one another inside the tread (il, 31, ^ 1). 5 · - Tire tread according to claim k, characterized in that communicating passages (l ^ a, l ^ + b, 3 * f, W) form a rectilinear or dendritic network of passages. 6.- Tire tread according to any one of the preceding claims, characterized in that the water evacuation passage (kk, 7k, 9 * f) or each of them is carried out in such a way that, when the tread (5l, 71, 91) is part of a tire, the only communication of the passage 7 ^, 9 * 0 or of each of them with the outside of the tire passes through the openings (53 , 73, 93) he the rolling hande. 7 · - tire tread according to any one of claims 1 to 5, characterized in that the water evacuation passage (l ^ a, l * fb, 3 ** "* f * 0 or each of them is shaped in such a way that, when the rolling hande (il, 31, * KL) is part of a tire, the passage or at least certain passages (l * + a, l * fb, 3 ^? * + * 0 communicate with the outside of the tire in the region of the shoulders of the tire (12, 32, * + 2) outside the surface in contact with the ground (18, 38, * 1-8 ) and further communicate with the outside of the tire through the openings (13, 33, * K3) in the rolling hanger. 8. Tire tread according to any one of the preceding claims, characterized in that the surface in contact with the ground (128) of the tread (Big. 12) is provided with one or more grooves ( 120, 122). 9. Tire tread according to claim 8, characterized in that the groove or grooves (120, 122) are substantially circumferential. 10. Tire tread according to claim 8 or 9, characterized in that the groove or grooves (120, 122. do not intersect any opening (93) in the tread (Big. 12). 11. Tire tread according to claim 8 or 9 or 10, characterized in that the groove or grooves (120, 122) have no communication inside the tread (Big. 12) with a water evacuation passage (any 9 * 0. 12. Tire tread according to any one of the preceding claims, characterized in that the ♦ openings (13, 33, * + 3, 53, 73, 93) in the tread are distributed circumferentially in this strip of bearing such that the ground contact surface (18, 38, ^ 8, 58, 78, 128) has continuous strips of tread material which extend transversely or at an angle not exceeding ^ 0 ° relative to the transverse direction, over the entire width of the surface in contact with the ground, the continuity of the blades being interrupted only by the groove or grooves (120, 122) (Fig. 12) if they are provided. 13.- Tire tread according to any one of the preceding claims, characterized in that the tread (Fig. 12) has a first radially external part (126) which extends radially inwards at from the surface in contact with the ground (128) and a second radially internal part (127) situated more inwards in the radial direction of the tread than the radially external part 126, the first radially external part ( 126) containing only the openings (93) and the groove (s) (120, 122), provided that they are provided, and the second radially internal part (127) containing only the evacuation passage (s) water (9½) as well as the radially innermost parts of the groove (s) (120, 122), provided that they are provided and that they are deeper than the radial dimension of the radially outer part (126) of the tread. 1½.- Tire tread according to claim 13, characterized in that the overall volume of the openings (93) in the radially external part (126) of the tread is between 5 and 65% of the total volume of the radially outer part (126). 15 · “Tire tread according to claim 1 ^ t-, characterized in that the overall volume of the openings (93) in the radially external part (126) of the tread is between 10 and 50% of the volume total of the radially outer part (126). 16. A tire tread according to claim 13 or 1 ^ - or 15, characterized in that the overall volume of the evacuation passage (s) of water (9 ^) in the radially internal part (127) of the tread bearing is between 10 and 70% of the total volume of the radially internal part (127). 17 · - Tire tread according to Claim 16, characterized in that the overall volume of the water evacuation passage (s) (9 * 0 in the radially internal part (127) of the tread is between 15 and 50% of the total volume of the radially internal part (127). 18.- Tire tread according to any one of the preceding claims, characterized in that the openings (13, 33, ^ 3, 53, 73, 93) have individual transverse sections not less than 9 mm . 19 · - Tire tread according to any one of the preceding claims, characterized in that the water drainage passage (s) (l ^ a, l ^ b, 31+, Λ1) -, 5 ^, 7 ^, 9 ^) have a cross section and dimensions such that they remain permanently open and that they are not compressed enough to close in the part of the tread in contact with the ground, when this tread is part of a tire, under the weight of a vehicle supported by the tire. 20.- Tire tread according to claim 19, characterized in that the water evacuation passage or each of them (l ^ a, l ^ b, 31 * -, 5 * +, 7 * + , 9 * +) has a minimum dimension s of 2 mm in a radial direction with respect to the "tread. 21. Tire comprising a carcass, characterized in that it includes a tread according to any one of the preceding claims. 22. Tire according to claim 21, characterized in that the tread came in one piece with the carcass. 23 · - Tire according to claim 21, characterized in that the tread is shaped independently of the carcass and is subsequently united or fixed to the »carcass to form a complete tire. 2 ^ .- Tire according to claim 21, characterized in that the carcass comprises a radially internal part of the tread which contains the water evacuation passage or passages molded with this part, and the radially external part of the tread containing the openings is formed separately and is subsequently united or fixed to the carcass on the radially internal part, the openings coinciding with the passage or passages to form the complete assembly of the carcass and the tread. 25. A method of manufacturing the tire tread according to any one of claims 1 to 20, characterized in that a tread tape is molded from an elastomeric material in a mold of internal shape and dimensions corresponding to substance to the final shape required of the tread tape. 26. The method of claim 25, characterized in that partially or completely vulcanizes the tread tape while it is in the mold or after its removal from the mold. ft T 27 · - Method for manufacturing the tire tread according to any one of claims 1 to 20, in which the water evacuation passage or each of them must be arranged circumferentially in the finished tread, characterized in that an elastomeric material is extracted by a die whose orifice has a cross section corresponding in substance to that of a tread tape without openings, the required openings are then formed and the tread is cut extradited into ribbons of the required length. 28.- Method according to claim 27, characterized in that the extrusion orifice has a section capable of forming * one or more circumferential grooves in the tread as it is extradited. 29 · - Method according to claim 27 or 28, characterized in that vulcanizes the extradited tread partially or completely before cutting it into ribbons or after this cutting. 30.- A method of manufacturing a tire, characterized in that: (i) a strip of the tread is prepared according to any one of claims 1 to 20; (ii) a vulcanized or vulcanized sand carcass is coated with a hot vulcanizable tread solution; (iii) a layer of non-vulcanized rubber tread is attached to the tire carcass; (iv) the tread tape is applied to the carcass and the ends of the tape are joined, and (v) the tire is wrapped in a strip of vulcanized rubber and the whole is vulcanized. 31 · ”The method of claim 30 wherein the carcass of the tire is vulcanized, characterized in that ♦ the carcass is prepared by grating before applying the tread solution. 32.- A method of constructing a tire, characterized in that: (i) a vulcanized tire carcass is constructed so that it has a raised circumferential band in each shoulder region (Pig. 8); (ii) forming a tire tread ring according to any one of claims 1 to 20 (Pig. 7), and (iii) fitting the tread ring on the carcass between the raised circumferential bands (Pig. 8).