CA1100858A - Heavy duty pneumatic tire - Google Patents
Heavy duty pneumatic tireInfo
- Publication number
- CA1100858A CA1100858A CA297,296A CA297296A CA1100858A CA 1100858 A CA1100858 A CA 1100858A CA 297296 A CA297296 A CA 297296A CA 1100858 A CA1100858 A CA 1100858A
- Authority
- CA
- Canada
- Prior art keywords
- pneumatic tire
- accordance
- parts
- rubber
- cushion elements
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
- B60C15/00—Tyre beads, e.g. ply turn-up or overlap
- B60C15/06—Flipper strips, fillers, or chafing strips and reinforcing layers for the construction of the bead
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
- B60C15/00—Tyre beads, e.g. ply turn-up or overlap
- B60C15/06—Flipper strips, fillers, or chafing strips and reinforcing layers for the construction of the bead
- B60C15/0603—Flipper strips, fillers, or chafing strips and reinforcing layers for the construction of the bead characterised by features of the bead filler or apex
- B60C15/0607—Flipper strips, fillers, or chafing strips and reinforcing layers for the construction of the bead characterised by features of the bead filler or apex comprising several parts, e.g. made of different rubbers
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
- B60C9/00—Reinforcements or ply arrangement of pneumatic tyres
- B60C9/18—Structure or arrangement of belts or breakers, crown-reinforcing or cushioning layers
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Tires In General (AREA)
- Packaging Of Annular Or Rod-Shaped Articles, Wearing Apparel, Cassettes, Or The Like (AREA)
Abstract
A HEAVY DUTY PNEUMATIC TIRE
ABSTRACT OF THE DISCLOSURE
An improved heavy duty pneumatic tire is disclosed which includes a carcass ply of rubberized metallic cord fabric that is wrapped around bead cores to form turnups.
Annular apex strips are disposed between the carcass ply and the turnups and abut the carcass ply along their axially inward side. Reinforcement strips of rubberized metallic cord fabric may be provided. These strips are wrapped about the bead cores and form radially outward extensions of the turnups. Enveloping and bonded to the terminal edges of the turnups and the terminal edges of the reinforcement strips if provided, are cushion elements of soft rubber having high restorability. The cushion elements isolate the terminal edges from the carcass ply and render the bead area and lower sidewall portion of the tire more flexible to inhibit separa-tion of the rubberized cords at the terminal edges. Likewise, similar soft rubber cushion elements may envelope and be bonded to the edges of rubberized metallic cord plies forming the reinforcement belt for the tread of the tire to prevent separation along the edges of these plies.
ABSTRACT OF THE DISCLOSURE
An improved heavy duty pneumatic tire is disclosed which includes a carcass ply of rubberized metallic cord fabric that is wrapped around bead cores to form turnups.
Annular apex strips are disposed between the carcass ply and the turnups and abut the carcass ply along their axially inward side. Reinforcement strips of rubberized metallic cord fabric may be provided. These strips are wrapped about the bead cores and form radially outward extensions of the turnups. Enveloping and bonded to the terminal edges of the turnups and the terminal edges of the reinforcement strips if provided, are cushion elements of soft rubber having high restorability. The cushion elements isolate the terminal edges from the carcass ply and render the bead area and lower sidewall portion of the tire more flexible to inhibit separa-tion of the rubberized cords at the terminal edges. Likewise, similar soft rubber cushion elements may envelope and be bonded to the edges of rubberized metallic cord plies forming the reinforcement belt for the tread of the tire to prevent separation along the edges of these plies.
Description
llOQ13S8 BACKGROUND OF THE INVENTION
1. Field of the Invention This invention relates to pneumatic vehicle tires and more particularly to novel bead and shoulder area constructions for heavy duty pneumatic tires which reduce ply edge separation.
1. Field of the Invention This invention relates to pneumatic vehicle tires and more particularly to novel bead and shoulder area constructions for heavy duty pneumatic tires which reduce ply edge separation.
2. Prior Art In the case of all vehicle tires containing plies of rubberized or similar metallic reinforcement elements there arise problems, in particular at the edges of the plies. During the manufacturing of the tire, sharp metallic cutting edges may have been created along those edges of the plies which are cut during the manufacturing process. This holds true in particular for large vehicle tires designed for heavy-duty applications since the dimensions of the steel cords used for such tires exceed by a multiple those of the steel cords utilized in passenger car tires. The extent of potential damage is of corresponding magnitude.
It will be possible to gain an understanding of the problem by looking at the various stages of tire ~anufacture.
The cord fabric used for the tire is manufactured in the form of a web of considerable length and is, essentially, steel or metallic cords embedded in a rubber compound. The various cord plies for the carcass and for the reinforcement belt are cut from this web at a bias in the form of strips of a certain width. This cutting creates exposed, rubber bared steel surfaces along the edges of the plies. Moreover, along the cut edges, the plies exhibit bared steel cord ends of different lengths which, as a result of squeezing and bending action in the course of the cutting operation, are irregularly deformed.
In the finished tire, these edges constitute a problem of considerable significance. The tire components adjacent these reinforced plies generally are rubber compounds that are highly .
unsuited for constant contact with such bare steel edges under operational loads. Because of the multiplicity of forces to which the finished tire is subjected to during operation, there result inherent movements of the individual tire components with respect to one another so that the edges of the cord plies and the adjoining tire components tend to rub against one another.
The result is a break-down of the adjacent rubber components and, in addition, separation of the cord from the rubber at the edges of the plies. This results, ultimately, in the complete destruc-tion of the tire.
Attempts have been made to eliminate the hazards of separation in a steel cord carcass or to minimize its effects.
For instance, in U.S. Patent no. 3,392,773, it was proposed, inter alia, that the ends of the carcass flipper be hemmed on both sides with rubber strips. Different arrangements of filler strips in the form of inserts of varying hardness in the bead area are proposed in U.S. Patent nos. 3,682,223, 3,722,568 and 3,921,693 in attempts to prevent failures and separations at the turnup portions when the tire is deformed due to load. In French Patent no. 2,127,163 an element made of rubber of medium softness is used to cover the ends of the turnup and to reduce the friction betweeen -the hard rubber ply of the bead and the balance of the tire -components.
Even in the shoulder area of the tire, specifically with regard to the edges of the reinforcement belt plies beneath the tread profile protective methods have been advanced, such as those in U.S. Patent nos. 3,512,668 and 4,006,766 which show end cushions under the tread adjacent the ply edges. In U.S. Patent no.
It will be possible to gain an understanding of the problem by looking at the various stages of tire ~anufacture.
The cord fabric used for the tire is manufactured in the form of a web of considerable length and is, essentially, steel or metallic cords embedded in a rubber compound. The various cord plies for the carcass and for the reinforcement belt are cut from this web at a bias in the form of strips of a certain width. This cutting creates exposed, rubber bared steel surfaces along the edges of the plies. Moreover, along the cut edges, the plies exhibit bared steel cord ends of different lengths which, as a result of squeezing and bending action in the course of the cutting operation, are irregularly deformed.
In the finished tire, these edges constitute a problem of considerable significance. The tire components adjacent these reinforced plies generally are rubber compounds that are highly .
unsuited for constant contact with such bare steel edges under operational loads. Because of the multiplicity of forces to which the finished tire is subjected to during operation, there result inherent movements of the individual tire components with respect to one another so that the edges of the cord plies and the adjoining tire components tend to rub against one another.
The result is a break-down of the adjacent rubber components and, in addition, separation of the cord from the rubber at the edges of the plies. This results, ultimately, in the complete destruc-tion of the tire.
Attempts have been made to eliminate the hazards of separation in a steel cord carcass or to minimize its effects.
For instance, in U.S. Patent no. 3,392,773, it was proposed, inter alia, that the ends of the carcass flipper be hemmed on both sides with rubber strips. Different arrangements of filler strips in the form of inserts of varying hardness in the bead area are proposed in U.S. Patent nos. 3,682,223, 3,722,568 and 3,921,693 in attempts to prevent failures and separations at the turnup portions when the tire is deformed due to load. In French Patent no. 2,127,163 an element made of rubber of medium softness is used to cover the ends of the turnup and to reduce the friction betweeen -the hard rubber ply of the bead and the balance of the tire -components.
Even in the shoulder area of the tire, specifically with regard to the edges of the reinforcement belt plies beneath the tread profile protective methods have been advanced, such as those in U.S. Patent nos. 3,512,668 and 4,006,766 which show end cushions under the tread adjacent the ply edges. In U.S. Patent no.
3,799,233 there is disclosed a construction in which a cushion element is composed of rubber and elongated shaped particles. In French Patent no. 1,389,428 the edges of the plies are covered with rubber profiles.
1~0()8S8 The use of rubber strips as a covering means is unsatisfactory with regard to both the edges of the turnup and belt since rubber strips may, after prolonged use, separate from the adjacent tire components and thus be unable effectively to prevent separations in the edges. Moreover, such rubber strips create, particularly in the tire bead, an inherent weakness.
Furthermore, it is known in the art that it is possible to affect the bonding of rubber to steel through the admixing of adhesion-promoting agents to the vulcanization compound. In the publication Rubber, Asbestos, Plastics 29, 749 (1976) there are described rubber compounds that contain silicic acid, resorcinol and hexamethylene-tetramine as agents designed to improve the adhesiveness of natural or synthetic rubber to steel surfaces.
This reference does, however, not contain any suggestions for the solution of the aforementioned problems attending the building of steel cord belted tires.
It is towards elimination of these and other problems that the present invention is directed.
SUM~ARY OF THE I VhrNTION
1. Purposes of the Invention It is an object of the present invention to provide an improved heavy duty pneumatic tire having a novel bead construction capable of preventing failures or separations at the edges of the tire plies.
Another object of the present invention is to provide an improved heavy duty pneumatic tire having a novel shoulder construction capable of preventing failures or separations at the edges of the reinforcement belt plies.
A further object of the present invention is to provide a formulation for a cushion element usable in the bead and shoulder regions of the tire to prevent failures or separations at the edges of the tire plies.
In accordance with one broad aspect, the invention relates to a pneumatic tire comprising (a) a pair of annular bead cores; (b) sidewalls; (c) a carcass of at least one ply of rubberized metallic cord fabric having its end portions wrapped radially around said bead cores to form turnups which are axially displaced from the remaining portions of said carcass; (d) an annular apex strip disposed between said carcass and each of said turnups, said annular apex strip extending radially of and from each of said bead cores and contacting said carcass along its axially inward surface; and (e) a cushion element of a soft rubber compound of high restorability having a coefficient of restitution of .55 to .65 and having a Shore A hardness of between 50 and 65, which Shore A hardness is less than that of the apex strip and carcass of said cushion element, enveloping the terminal edges of said turnups extending radially outwardly from between said apex strips and said turnups into said 110~)858 sidewalls and being of a material having a high adhesion to the metallic cords forming the carcass thereby isolating the terminal edge of said turnup from said carcass ply and rendering the bead and lower sidewall portions of said pneumatic tire more flexible to inhibit separation of said cords at said terminal edges.
Still other objects in part will be obvious and in part will be apparent as the description proceeds.
2. Brief Description of the Invention Generally speaking, the above and other objects are accomplished by a pneumatic tire including a pair of annular bead cores, sidewalls and a tread profile. Wrapped around the bead cores so as to create turnups is at least one carcass ply of rubberized metallic cord fabric. An annular apex strip is disposed between the carcass ply and each of the turnups. The apex strips extend radially of and from each bead core and abut the carcass ply along their axially inward side. A cushion element of a soft rubber compound of high restorability envelopes and is bonded to the terminal edges of each of the turnups. The cushion elements extend radially ~ i6 -4a-l~OU858 outwardly from between the apex strips and the turnups into the sidewall portions of the tire to isolate the terminal edges of the turnups from the carcass ply and to render the bead areas and lower sidewall areas of the tire more flexible to inhibit separation at the terminal edges of the turnups.
The cushion elements are softer than the surrounding tire components and may have a Shore A hardness of from between about 50 to about 65.
In one alternative embodiment, reinforcement strips of rubberized metallic cord fabric are wrapped around the bead cores to form radial extensions of the turnups. The terminal edges of these strips are also enveloped by the cushion elements. The terminal edges of the reinforcement strips, in another embodiment, may be spaced from the terminal edges of the turnups, but still be enveloped by the cushion elements.
The pneumatic tire may include a reinforcement belt positioned beneath the tread profile, having a plurality of superimposed plies of rubberized metallic cord fabric. Cushion elements of a soft rubber compound having a high restorability envelope and are bonded to the edges of the plies so as to reduce the chances of separation occurring at the ply edges. In one embodiment the cushion elements extend axially inwardly between the carcass ply and the immediately adjacent reinforcement belt ply and radially inwardly to the sidewalls of the tire. In an alternative embodiment, the cushion elements also extend between at least two of the reinforcement belt plies.
The invention consists of the features of construction and arrangement of parts which will be detailed hereinafter and described in the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
.
While the specification concludes with claims par-ticularly pointing out and distinctly claiming the subject matter 11(~08S8 regarded as the invention herein, it is believed that the invention will be better understood from the following descrip-tion when read in conjunction with the accompanying drawings, in which:
Fig. 1 is an enlarged partial cross-sectional view of one half of a pneumatic tire constructed in accordance with embodiments of the present invention;
Fig. 2 is a view similar to Fig. 1 showing other embodiments of the present invention; and Fig. 3 is a partial cross-sectional view of a bead portion of a further embodiment of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS ~ -As used in the specification and the claims, the terms "axially inward" and "axially outward" are used with reference to a sidewall of the tire, that is, "axially inward" refers to a vector extending from the sidewall to the opposite sidewall.
Conversely, "axially outward" refers to a vector extending out-wardly away from the sidewall. The terms "radially inward" and "radially outward" are used with reference to the axis of rotation of the tire, that is, "radially inward" refers to a vector extending from the tread profile of the tire to the axis, while, the term "radially outward" refers to a vector extending from the axis toward the tread profile.
Referring now to the drawings, there is shown in Fig. 1 in partial section one half of a pneumatic tire constructed in accordance with embodiments of the present invention identified by the reference numeral 10. The tire 10 is a size 12.00 R 20 truck tire on a 5 shoulder rim 11. While only one half of the tire is illustrated, it is to be understood that the half not illustrated is the same as that illustrated but opposite in hand.
The tire 10 includes a ground engaging tread portion 12 extending circumferentially of the tire and a sidewall portion 14 extending ~lOQ858 from the lateral edge 16 of the tread 12 to a bead portion 18.
A carcass 20 of at least one ply of rubberized steel cord fabric extends circumferentially about the tire 10 beneath the tread 12.
The cords in the carcass 20 are arranged radially, i.e., sub-stantially 90 to a circumferential direction of the tire. The end 22 of the carcass ply is wrapped radially outwardly about a bead core 24 to form a turnup or carcass flipper 26.
Extending circumferentially of the tire and radially above the bead core 24 between the turnup 26 and the carcass ply 20 is a hard rubber annular reinforcement or apex strip 28. The apex strip 28 is substantially at its base 30 as wide as the bead core 24 and, as shown, may encompass the bead core. It tapers smoothly and gradually to a point at its radially outer extremity 32. In addition, the apex strip 28 abuts the carcass ply 20 substantially along its entire axially inward side 34 as shown.
Wrapped about the bead core 24 and in direct over-lapping relationship with the turnup 26 may be a reinforcement strip 36 of rubberized steel cord fabric. The axially outward terminal edge 38 of the reinforcement strip 36 is positioned radially outwardly of the terminal edge 40 of the turnup 26 so that the reinforcement strip 36 forms a radially outward extension of the turnup. The steel cords in the reinforcement strip 36 are oriented with respect to the equatorial axis X-X of the tire so as to create an angle ~ with the steel cords of the carcass ply.
As mentioned hereinabove, the cords in the carcass ply 20 extend at an angle of substantially 90 with respect to the equatorial axis X-X and the cords in the reinforcing strip 36 may lie at an angle of 60 with respect to the axis.
In accordance with one embodiment of the present invention, an annular rubber cushion element or insert 42 encompasses the radially outward terminal edge 40 of the turnup 26 and if a reinforcement strip 36 is provided, its terminal edge ~10~t~358 38. The cushion element 42 abuts the axially outer edge 44 of the apex strip 28 and the carcass ply 20 as well as the sidewall 14. The cushion element 42 is formed of a rubber compound, here-inafter described in detail, which when vulcanized, has a hardness less than the hardness of the surrounding rubber components. For example, the cushion element 42 may have a Shore A hardness of approximately 60, with the adjoining rubber portion of the apex strip 28, as well as the rubber coating of the carcass ply 20 and the reinforcement strip 36 being significantly harder, for instance, of a Shore A hardness of 80.
With continued reference to Fig. 1, it can be seen that the radially outward terminal edges 38 and 40 of the reinforcement strip 36 and the turnup 26 respectively are located approximately in the center of the cushion element 42. Preferably, the cushion element 42 has a cross-sectional shape of a lentil and is, at its thickest point, a multiple of thickness of the cords in the carcass ply and the reinforcement strip.
The cushion element 42 tapers to a point 46 at its radially inward extremity adjacent the apex strip 28 and to a point 48 at its radially outward extremity adjacent the carcass ply 20. The distance, measured radially, that the point 46 is from the terminal edge 38 of the reinforcement strip 36 is the same as the distance point 48 is from the same edge.
The concept of the present invention is applicable not only to a tire bead area construction but also to a shoulder area construction to reduce separation at the edges of the reinforce-ment belt. With continued reference to Fig. l, a reinforcement belt 50 includes a plurality of superimposed plies 52, 54 and 56 of rubberized steel cord, and a protector ply 58. The edges 60 and 62 of the plies 52 and 54 respectively are encased in a soft rubber cushion element 64 formulated in accordance with the present invention. The cushion element 64 has a sickle-shaped cross 1100~3S8 sectional configuration and is situated axially inwardly of the shoulder 16. The cushion element 64 extends axially inwardly between the ply 52 and the carcass ply 20 to a point proximate the equatorial axis X-X of the tire as well as radially inwardly into the sidewall 14 of the tire. In this construction, the cushion element 64 prevents contact between the steel cord ends at the edges 60 and 62 of the plies 52 and 54 and the carcass ply 20 and eliminates separation in the ply edges.
According to an alternative arrangement of the structure illustrated in Fig. 1, represented in Fig. 2, one half of a pneumatic truck tire 70 is mounted on a 15 shoulder rim 71 and includes a carcass ply 72 containing radially oriented rubberized steel cords. The carcass ply 72 is wrapped about a bead core 74 which may have a hexagonal cross-sectional configuration as shown.
In this embodiment, the radially outward terminal edge 76 of the turnup 78 is separated, i.e., axially spaced, from the radially outward edge 80 of the reinforcement strip 82. Both the edge 76 and the edge 80 are encased in a cushion element 84, which is similar in configuration to cushion element 42. The cushion element 84 is substantially wider than the cushion element 42 due to the spaced relationship of the edges 76 and 80.
Also illustrated in Fig. 2 is an alternative con-struction for the cushion element associated with the rein-forcement belt. Identified by the reference numeral 86, the cushion element extends axially inwardly not only between the ply 88 and the carcass ply 72, but also between the ply 88 and the immediately adjacent ply 89.
A further embodiment of the present invention is illustrated in Fig. 3 in which the carcass ply 90 is wrapped radially outwardly about a bead core 92. The radially outward terminal edge 94 of the turnup 96 and the terminal edge 98 of the reinforcement strip 100 are adjacent one another and bear llOC~858 against the sidewall 102. The cushion element 104 is positioned between the terminal edges 94 and 98 and the carcass ply 90 to maintain the edges in axially spaced relationship to the carcass ply 9 0 .
While both Figs. 1 and 2 contain details of cushion elements for the bead areas and shoulder areas of a pneumatic tire, it is to be appreciated that the scope of the present ~ .
llOQ858 invention is not limited to a pneumatic tire containing cushion elements in both of these areas. The cushion elements in one area of the pneumatic tire can function without the cushion element in the other area being present.
The rubber compounds for the above described cushion-elements in the bead area and for the cushion elements in the shoulder area of the tire and their vulcanization process are selected so that the elements provide elevated rebound elasticity and high adhesivity to the steel cord extremities. Preferably, these cushion elements have, as noted hereinabove, a comparatively low hardness compared with the surrounding components of the bead and of the tire sidewall a low permanent set and a low development of heat under dynamic deformation.
The rebound elasticity of the material is measured by striking the material with a hammer mounted on a pendulum which has been allowed to drop 90 from the horizontal. The coefficient of restitution is the height reached by the hammer on rebound divided by the total height from which the hammer fell in striking the element. The cushion elements of the present invention have a coefficient of restitution of between .55 and .65. The Shore A hardness of these elements as discussed above lies in the range of 50 to 65 and in particular around 60.
The cushion elements in accordance with the invention contain additives promoting the adhesion of rubber to steel, e.g., known materials such as resorcinol and methylene group donors, for instance ressorcinol-formaldehyde resins and 2-nitro-2-methyl-1-propanol or 1-aza-3,7-dioxy-5-hydroxy-methyl-dicyclo (3,3,0) octane, as well as active silicic acid.
Preferably resorcinol, hexamethylene tetramine and active silicic acid are used. These additives ensure firm bonding -1~
1100~58 of the exposed steel at the edges with the rubber surrounding them.
Table 1 is an example, without limitation, of a '' ' ' '' ~
.
-lla-- . , , : ,. . .
, , , , - , , . - . . .
:: . . . . . .
: . , , . ~ ~ , :
110(~858 rubber enwrapping compound from which the elements may be formed with the quantities being given in parts by weight with respect to 100 parts natural rubber.
100 parts natural rubber 20-30 parts reinforcing carbon black 2.5-3.5 parts sulfur 5-10 parts active silicic acid 1-3 parts resorcinol 1-2.5 parts hexamethylene tetramine The vulcanized products contain other standard addi-tives such as zinc oxide, zinc stearate, processing oils, adhesive cement, antioxidants, antiozonants, and accelerators.
Preferred compounds are compounds in which the rubber portion consists of natural rubber (NR). However, likewise suitable are mixtures of natural rubber with butadiene rubbers (BR), e.g., cis-1,4-polybutadiene rubber. Suitable compounding ratios of the rubber components are 30 to 100 parts, preferably at least 80 parts, of natural rubber per 70 to 0 parts of the butadiene rubber component. The preferred amount of carbon black is at around 25 parts and the preferred amount of sulfur at about 3 parts. The active silicic acid is preferably applied at the lower limit of the above-mentioned range, in other words, one uses preferably quantities of approximately 5 parts or only slightly increased amounts. Resorcinol is appropriately applied in an amount of approximately 2.5 parts and hexamethylene tetramine suitably in an amount of approximately 2 parts.
For an accelerator, N-cyclohexyl-2-benzothiazyl-sulfenamide can be used. Depending on the type of rubber that has been selected, one can use other suitable accelerators, such as the sulfenamide type.
The cushion elements are manufactured in the following ,' , llOU~358 manner. The cut and weighed raw rubber is first masticated in a kneader. It is then processed to a carbon black masterbatch by incorporating the following additives: silicic acid and resorcinol, processing oil, zinc compo~mds, carbon black, and the other additives, and mixing in a kneader. The resultant mixture is rolled out in sheet form, weighed, and cut to size in charges. Subsequently, the CBS accelerator and the HMT are added to the masterbatch. Following further processing in a kneader, renewed rolling, and cutting, the rubber material eventually assumes the form of a strip that can be used for tire building.
me manufacture of the tire involves the building up of the individual tire components on a tire building machine.
First, a cylindrical protector ply, made of rubber, is placed on a drum. Next the bead reinforcement strips as well as the steel cord carcass are positioned over the protector ply. A bead ring, a filler, and a rubber cushion element of the above-described compound, are placed on each side. The carcass extremities are -then flipped over into the inflated building state of the carcass.
Pressed onto the ends of the turnup are additional strips of rubber made out of the above-described compound. Following covering of the edges by means of a rim protecting band made of natural rubber, the carcass is completed. In a subsequent building process, this carcass body is endowed with the shape of a toroid by way of inflation.
Onto same, one applies and forces on under pressure, in the area of the later tire shoulder, additional rubber strips made out of the above-described compound and, in the crown area, the required belt plies made of steel cord, and then the tire sidewalls and, finally, the tread or the other way round. The resultant raw tire is finally vulcanized under pressure and heat in a heated press mold of a vulcanization press and endowed with its shape as a finished tire.
110(~58 The optimum choice of the components results on the one hand an elevated cross-linking density of the rubber and thus the favorable adhesion properties of the rubber cushion elements at the steel cord extremities, and on the other hand, the desirability that the elements be capable of absorbing a high portion of the deformation energy created during tire operation. As a result of the elevated adhesive strength, the rubber cushion elements and the steel cords combine to form a unit that effectively resists deterioration. The bonding creates a functional unit which is capable of absorbing a high portion of deformation energy and which reduces the effects of friction between the tire components by cushioning the movements of the steel cord ends and isolating the ends from other tire components.
In this context, truck tires having rubber cushion elements of the type disclosed herein failed to show any separation at the edges of the plies under the highly unfavorable operating conditions to which they were subjected in bench as well as in road tests.
It can be seen from the foregoing that the objects of the present invention, namely to provide an improved heavy duty pneumatic tire have been achieved by a pneumatic tire having a pair of annular bead cores, sidewalls and a tread profile. At least one ply of rubberized metallic cord fabric is wrapped around the bead cores to form turnups. Disposed between the carcass ply and the turnups are apex strips of hard rubber material. The apex strips extend radially from the bead cores and abut the carcass ply along their axially inward side. Cushion elements of a soft rubber compound having high restorability envelope and are bonded to the terminal edges of the turnups, and extend radially outwardly from between the apex strips and the turnups into the sidewalls so as to isolate the terminal edges of the turnups and to render the bead areas and the lower sidewall areas more flexible.
In an alternative embodiment, reinforcement strips of rubberized metallic cord fabric are wrapped about the bead cores and their terminal edges are also enveloped by the cushion elements. The terminal edges of the turnups and the reinforce-ment strips may be spaced apart axially, but are still enveloped by the cushion element.
The pneumatic tire may also include a reinforcement belt beneath the tread profile which includes a plurality of superimposed rubberized metallic cord fabric plies. Cushion elements of a soft rubber compound having high restorability envelope and are bonded to the edges of the plies so as to reduce ply edge separation. In one embodiment the cushion elements extend axially inwardly between the carcass ply and the immediately adjacent reinforcement belt ply and radially inwardly into the sidewalls of the tire. Alternatively, the cushion elements may also extend between at least two of the reinforcement belt plies.
While in accordance with the patent statute, preferred and alternative embodiments have been described in detail, it is to be understood that the invention is not limited thereto or thereby.
1~0()8S8 The use of rubber strips as a covering means is unsatisfactory with regard to both the edges of the turnup and belt since rubber strips may, after prolonged use, separate from the adjacent tire components and thus be unable effectively to prevent separations in the edges. Moreover, such rubber strips create, particularly in the tire bead, an inherent weakness.
Furthermore, it is known in the art that it is possible to affect the bonding of rubber to steel through the admixing of adhesion-promoting agents to the vulcanization compound. In the publication Rubber, Asbestos, Plastics 29, 749 (1976) there are described rubber compounds that contain silicic acid, resorcinol and hexamethylene-tetramine as agents designed to improve the adhesiveness of natural or synthetic rubber to steel surfaces.
This reference does, however, not contain any suggestions for the solution of the aforementioned problems attending the building of steel cord belted tires.
It is towards elimination of these and other problems that the present invention is directed.
SUM~ARY OF THE I VhrNTION
1. Purposes of the Invention It is an object of the present invention to provide an improved heavy duty pneumatic tire having a novel bead construction capable of preventing failures or separations at the edges of the tire plies.
Another object of the present invention is to provide an improved heavy duty pneumatic tire having a novel shoulder construction capable of preventing failures or separations at the edges of the reinforcement belt plies.
A further object of the present invention is to provide a formulation for a cushion element usable in the bead and shoulder regions of the tire to prevent failures or separations at the edges of the tire plies.
In accordance with one broad aspect, the invention relates to a pneumatic tire comprising (a) a pair of annular bead cores; (b) sidewalls; (c) a carcass of at least one ply of rubberized metallic cord fabric having its end portions wrapped radially around said bead cores to form turnups which are axially displaced from the remaining portions of said carcass; (d) an annular apex strip disposed between said carcass and each of said turnups, said annular apex strip extending radially of and from each of said bead cores and contacting said carcass along its axially inward surface; and (e) a cushion element of a soft rubber compound of high restorability having a coefficient of restitution of .55 to .65 and having a Shore A hardness of between 50 and 65, which Shore A hardness is less than that of the apex strip and carcass of said cushion element, enveloping the terminal edges of said turnups extending radially outwardly from between said apex strips and said turnups into said 110~)858 sidewalls and being of a material having a high adhesion to the metallic cords forming the carcass thereby isolating the terminal edge of said turnup from said carcass ply and rendering the bead and lower sidewall portions of said pneumatic tire more flexible to inhibit separation of said cords at said terminal edges.
Still other objects in part will be obvious and in part will be apparent as the description proceeds.
2. Brief Description of the Invention Generally speaking, the above and other objects are accomplished by a pneumatic tire including a pair of annular bead cores, sidewalls and a tread profile. Wrapped around the bead cores so as to create turnups is at least one carcass ply of rubberized metallic cord fabric. An annular apex strip is disposed between the carcass ply and each of the turnups. The apex strips extend radially of and from each bead core and abut the carcass ply along their axially inward side. A cushion element of a soft rubber compound of high restorability envelopes and is bonded to the terminal edges of each of the turnups. The cushion elements extend radially ~ i6 -4a-l~OU858 outwardly from between the apex strips and the turnups into the sidewall portions of the tire to isolate the terminal edges of the turnups from the carcass ply and to render the bead areas and lower sidewall areas of the tire more flexible to inhibit separation at the terminal edges of the turnups.
The cushion elements are softer than the surrounding tire components and may have a Shore A hardness of from between about 50 to about 65.
In one alternative embodiment, reinforcement strips of rubberized metallic cord fabric are wrapped around the bead cores to form radial extensions of the turnups. The terminal edges of these strips are also enveloped by the cushion elements. The terminal edges of the reinforcement strips, in another embodiment, may be spaced from the terminal edges of the turnups, but still be enveloped by the cushion elements.
The pneumatic tire may include a reinforcement belt positioned beneath the tread profile, having a plurality of superimposed plies of rubberized metallic cord fabric. Cushion elements of a soft rubber compound having a high restorability envelope and are bonded to the edges of the plies so as to reduce the chances of separation occurring at the ply edges. In one embodiment the cushion elements extend axially inwardly between the carcass ply and the immediately adjacent reinforcement belt ply and radially inwardly to the sidewalls of the tire. In an alternative embodiment, the cushion elements also extend between at least two of the reinforcement belt plies.
The invention consists of the features of construction and arrangement of parts which will be detailed hereinafter and described in the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
.
While the specification concludes with claims par-ticularly pointing out and distinctly claiming the subject matter 11(~08S8 regarded as the invention herein, it is believed that the invention will be better understood from the following descrip-tion when read in conjunction with the accompanying drawings, in which:
Fig. 1 is an enlarged partial cross-sectional view of one half of a pneumatic tire constructed in accordance with embodiments of the present invention;
Fig. 2 is a view similar to Fig. 1 showing other embodiments of the present invention; and Fig. 3 is a partial cross-sectional view of a bead portion of a further embodiment of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS ~ -As used in the specification and the claims, the terms "axially inward" and "axially outward" are used with reference to a sidewall of the tire, that is, "axially inward" refers to a vector extending from the sidewall to the opposite sidewall.
Conversely, "axially outward" refers to a vector extending out-wardly away from the sidewall. The terms "radially inward" and "radially outward" are used with reference to the axis of rotation of the tire, that is, "radially inward" refers to a vector extending from the tread profile of the tire to the axis, while, the term "radially outward" refers to a vector extending from the axis toward the tread profile.
Referring now to the drawings, there is shown in Fig. 1 in partial section one half of a pneumatic tire constructed in accordance with embodiments of the present invention identified by the reference numeral 10. The tire 10 is a size 12.00 R 20 truck tire on a 5 shoulder rim 11. While only one half of the tire is illustrated, it is to be understood that the half not illustrated is the same as that illustrated but opposite in hand.
The tire 10 includes a ground engaging tread portion 12 extending circumferentially of the tire and a sidewall portion 14 extending ~lOQ858 from the lateral edge 16 of the tread 12 to a bead portion 18.
A carcass 20 of at least one ply of rubberized steel cord fabric extends circumferentially about the tire 10 beneath the tread 12.
The cords in the carcass 20 are arranged radially, i.e., sub-stantially 90 to a circumferential direction of the tire. The end 22 of the carcass ply is wrapped radially outwardly about a bead core 24 to form a turnup or carcass flipper 26.
Extending circumferentially of the tire and radially above the bead core 24 between the turnup 26 and the carcass ply 20 is a hard rubber annular reinforcement or apex strip 28. The apex strip 28 is substantially at its base 30 as wide as the bead core 24 and, as shown, may encompass the bead core. It tapers smoothly and gradually to a point at its radially outer extremity 32. In addition, the apex strip 28 abuts the carcass ply 20 substantially along its entire axially inward side 34 as shown.
Wrapped about the bead core 24 and in direct over-lapping relationship with the turnup 26 may be a reinforcement strip 36 of rubberized steel cord fabric. The axially outward terminal edge 38 of the reinforcement strip 36 is positioned radially outwardly of the terminal edge 40 of the turnup 26 so that the reinforcement strip 36 forms a radially outward extension of the turnup. The steel cords in the reinforcement strip 36 are oriented with respect to the equatorial axis X-X of the tire so as to create an angle ~ with the steel cords of the carcass ply.
As mentioned hereinabove, the cords in the carcass ply 20 extend at an angle of substantially 90 with respect to the equatorial axis X-X and the cords in the reinforcing strip 36 may lie at an angle of 60 with respect to the axis.
In accordance with one embodiment of the present invention, an annular rubber cushion element or insert 42 encompasses the radially outward terminal edge 40 of the turnup 26 and if a reinforcement strip 36 is provided, its terminal edge ~10~t~358 38. The cushion element 42 abuts the axially outer edge 44 of the apex strip 28 and the carcass ply 20 as well as the sidewall 14. The cushion element 42 is formed of a rubber compound, here-inafter described in detail, which when vulcanized, has a hardness less than the hardness of the surrounding rubber components. For example, the cushion element 42 may have a Shore A hardness of approximately 60, with the adjoining rubber portion of the apex strip 28, as well as the rubber coating of the carcass ply 20 and the reinforcement strip 36 being significantly harder, for instance, of a Shore A hardness of 80.
With continued reference to Fig. 1, it can be seen that the radially outward terminal edges 38 and 40 of the reinforcement strip 36 and the turnup 26 respectively are located approximately in the center of the cushion element 42. Preferably, the cushion element 42 has a cross-sectional shape of a lentil and is, at its thickest point, a multiple of thickness of the cords in the carcass ply and the reinforcement strip.
The cushion element 42 tapers to a point 46 at its radially inward extremity adjacent the apex strip 28 and to a point 48 at its radially outward extremity adjacent the carcass ply 20. The distance, measured radially, that the point 46 is from the terminal edge 38 of the reinforcement strip 36 is the same as the distance point 48 is from the same edge.
The concept of the present invention is applicable not only to a tire bead area construction but also to a shoulder area construction to reduce separation at the edges of the reinforce-ment belt. With continued reference to Fig. l, a reinforcement belt 50 includes a plurality of superimposed plies 52, 54 and 56 of rubberized steel cord, and a protector ply 58. The edges 60 and 62 of the plies 52 and 54 respectively are encased in a soft rubber cushion element 64 formulated in accordance with the present invention. The cushion element 64 has a sickle-shaped cross 1100~3S8 sectional configuration and is situated axially inwardly of the shoulder 16. The cushion element 64 extends axially inwardly between the ply 52 and the carcass ply 20 to a point proximate the equatorial axis X-X of the tire as well as radially inwardly into the sidewall 14 of the tire. In this construction, the cushion element 64 prevents contact between the steel cord ends at the edges 60 and 62 of the plies 52 and 54 and the carcass ply 20 and eliminates separation in the ply edges.
According to an alternative arrangement of the structure illustrated in Fig. 1, represented in Fig. 2, one half of a pneumatic truck tire 70 is mounted on a 15 shoulder rim 71 and includes a carcass ply 72 containing radially oriented rubberized steel cords. The carcass ply 72 is wrapped about a bead core 74 which may have a hexagonal cross-sectional configuration as shown.
In this embodiment, the radially outward terminal edge 76 of the turnup 78 is separated, i.e., axially spaced, from the radially outward edge 80 of the reinforcement strip 82. Both the edge 76 and the edge 80 are encased in a cushion element 84, which is similar in configuration to cushion element 42. The cushion element 84 is substantially wider than the cushion element 42 due to the spaced relationship of the edges 76 and 80.
Also illustrated in Fig. 2 is an alternative con-struction for the cushion element associated with the rein-forcement belt. Identified by the reference numeral 86, the cushion element extends axially inwardly not only between the ply 88 and the carcass ply 72, but also between the ply 88 and the immediately adjacent ply 89.
A further embodiment of the present invention is illustrated in Fig. 3 in which the carcass ply 90 is wrapped radially outwardly about a bead core 92. The radially outward terminal edge 94 of the turnup 96 and the terminal edge 98 of the reinforcement strip 100 are adjacent one another and bear llOC~858 against the sidewall 102. The cushion element 104 is positioned between the terminal edges 94 and 98 and the carcass ply 90 to maintain the edges in axially spaced relationship to the carcass ply 9 0 .
While both Figs. 1 and 2 contain details of cushion elements for the bead areas and shoulder areas of a pneumatic tire, it is to be appreciated that the scope of the present ~ .
llOQ858 invention is not limited to a pneumatic tire containing cushion elements in both of these areas. The cushion elements in one area of the pneumatic tire can function without the cushion element in the other area being present.
The rubber compounds for the above described cushion-elements in the bead area and for the cushion elements in the shoulder area of the tire and their vulcanization process are selected so that the elements provide elevated rebound elasticity and high adhesivity to the steel cord extremities. Preferably, these cushion elements have, as noted hereinabove, a comparatively low hardness compared with the surrounding components of the bead and of the tire sidewall a low permanent set and a low development of heat under dynamic deformation.
The rebound elasticity of the material is measured by striking the material with a hammer mounted on a pendulum which has been allowed to drop 90 from the horizontal. The coefficient of restitution is the height reached by the hammer on rebound divided by the total height from which the hammer fell in striking the element. The cushion elements of the present invention have a coefficient of restitution of between .55 and .65. The Shore A hardness of these elements as discussed above lies in the range of 50 to 65 and in particular around 60.
The cushion elements in accordance with the invention contain additives promoting the adhesion of rubber to steel, e.g., known materials such as resorcinol and methylene group donors, for instance ressorcinol-formaldehyde resins and 2-nitro-2-methyl-1-propanol or 1-aza-3,7-dioxy-5-hydroxy-methyl-dicyclo (3,3,0) octane, as well as active silicic acid.
Preferably resorcinol, hexamethylene tetramine and active silicic acid are used. These additives ensure firm bonding -1~
1100~58 of the exposed steel at the edges with the rubber surrounding them.
Table 1 is an example, without limitation, of a '' ' ' '' ~
.
-lla-- . , , : ,. . .
, , , , - , , . - . . .
:: . . . . . .
: . , , . ~ ~ , :
110(~858 rubber enwrapping compound from which the elements may be formed with the quantities being given in parts by weight with respect to 100 parts natural rubber.
100 parts natural rubber 20-30 parts reinforcing carbon black 2.5-3.5 parts sulfur 5-10 parts active silicic acid 1-3 parts resorcinol 1-2.5 parts hexamethylene tetramine The vulcanized products contain other standard addi-tives such as zinc oxide, zinc stearate, processing oils, adhesive cement, antioxidants, antiozonants, and accelerators.
Preferred compounds are compounds in which the rubber portion consists of natural rubber (NR). However, likewise suitable are mixtures of natural rubber with butadiene rubbers (BR), e.g., cis-1,4-polybutadiene rubber. Suitable compounding ratios of the rubber components are 30 to 100 parts, preferably at least 80 parts, of natural rubber per 70 to 0 parts of the butadiene rubber component. The preferred amount of carbon black is at around 25 parts and the preferred amount of sulfur at about 3 parts. The active silicic acid is preferably applied at the lower limit of the above-mentioned range, in other words, one uses preferably quantities of approximately 5 parts or only slightly increased amounts. Resorcinol is appropriately applied in an amount of approximately 2.5 parts and hexamethylene tetramine suitably in an amount of approximately 2 parts.
For an accelerator, N-cyclohexyl-2-benzothiazyl-sulfenamide can be used. Depending on the type of rubber that has been selected, one can use other suitable accelerators, such as the sulfenamide type.
The cushion elements are manufactured in the following ,' , llOU~358 manner. The cut and weighed raw rubber is first masticated in a kneader. It is then processed to a carbon black masterbatch by incorporating the following additives: silicic acid and resorcinol, processing oil, zinc compo~mds, carbon black, and the other additives, and mixing in a kneader. The resultant mixture is rolled out in sheet form, weighed, and cut to size in charges. Subsequently, the CBS accelerator and the HMT are added to the masterbatch. Following further processing in a kneader, renewed rolling, and cutting, the rubber material eventually assumes the form of a strip that can be used for tire building.
me manufacture of the tire involves the building up of the individual tire components on a tire building machine.
First, a cylindrical protector ply, made of rubber, is placed on a drum. Next the bead reinforcement strips as well as the steel cord carcass are positioned over the protector ply. A bead ring, a filler, and a rubber cushion element of the above-described compound, are placed on each side. The carcass extremities are -then flipped over into the inflated building state of the carcass.
Pressed onto the ends of the turnup are additional strips of rubber made out of the above-described compound. Following covering of the edges by means of a rim protecting band made of natural rubber, the carcass is completed. In a subsequent building process, this carcass body is endowed with the shape of a toroid by way of inflation.
Onto same, one applies and forces on under pressure, in the area of the later tire shoulder, additional rubber strips made out of the above-described compound and, in the crown area, the required belt plies made of steel cord, and then the tire sidewalls and, finally, the tread or the other way round. The resultant raw tire is finally vulcanized under pressure and heat in a heated press mold of a vulcanization press and endowed with its shape as a finished tire.
110(~58 The optimum choice of the components results on the one hand an elevated cross-linking density of the rubber and thus the favorable adhesion properties of the rubber cushion elements at the steel cord extremities, and on the other hand, the desirability that the elements be capable of absorbing a high portion of the deformation energy created during tire operation. As a result of the elevated adhesive strength, the rubber cushion elements and the steel cords combine to form a unit that effectively resists deterioration. The bonding creates a functional unit which is capable of absorbing a high portion of deformation energy and which reduces the effects of friction between the tire components by cushioning the movements of the steel cord ends and isolating the ends from other tire components.
In this context, truck tires having rubber cushion elements of the type disclosed herein failed to show any separation at the edges of the plies under the highly unfavorable operating conditions to which they were subjected in bench as well as in road tests.
It can be seen from the foregoing that the objects of the present invention, namely to provide an improved heavy duty pneumatic tire have been achieved by a pneumatic tire having a pair of annular bead cores, sidewalls and a tread profile. At least one ply of rubberized metallic cord fabric is wrapped around the bead cores to form turnups. Disposed between the carcass ply and the turnups are apex strips of hard rubber material. The apex strips extend radially from the bead cores and abut the carcass ply along their axially inward side. Cushion elements of a soft rubber compound having high restorability envelope and are bonded to the terminal edges of the turnups, and extend radially outwardly from between the apex strips and the turnups into the sidewalls so as to isolate the terminal edges of the turnups and to render the bead areas and the lower sidewall areas more flexible.
In an alternative embodiment, reinforcement strips of rubberized metallic cord fabric are wrapped about the bead cores and their terminal edges are also enveloped by the cushion elements. The terminal edges of the turnups and the reinforce-ment strips may be spaced apart axially, but are still enveloped by the cushion element.
The pneumatic tire may also include a reinforcement belt beneath the tread profile which includes a plurality of superimposed rubberized metallic cord fabric plies. Cushion elements of a soft rubber compound having high restorability envelope and are bonded to the edges of the plies so as to reduce ply edge separation. In one embodiment the cushion elements extend axially inwardly between the carcass ply and the immediately adjacent reinforcement belt ply and radially inwardly into the sidewalls of the tire. Alternatively, the cushion elements may also extend between at least two of the reinforcement belt plies.
While in accordance with the patent statute, preferred and alternative embodiments have been described in detail, it is to be understood that the invention is not limited thereto or thereby.
Claims (22)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A pneumatic tire comprising (a) a pair of annular bead cores;
(b) sidewalls;
(c) a carcass of at least one ply of rubberized metallic cord fabric having its end portions wrapped radially around said bead cores to form turnups which are axially displaced from the remaining portions of said carcass;
(d) an annular apex strip disposed between said carcass and each of said turnups, said annular apex strip extending radially of and from each of said bead cores and contacting said carcass along its axially inward surface; and (e) a cushion element of a soft rubber compound of high restorability having a coefficient of restitution of .55 to .65 and having a Shore A hardness of between 50°
and 65°, which Shore A hardness is less than that of the apex strip and carcass of said cushion element, enveloping the terminal edges of said turnups extending radially outwardly from between said apex strips and said turnups into said sidewalls and being of a material having a high adhesion to the metallic cords forming the carcass thereby isolating the terminal edge of each turnup from said carcass ply and rendering the bead and lower sidewall portions of said pneumatic tire more flexible to inhibit separation of said cords at said terminal edges.
(b) sidewalls;
(c) a carcass of at least one ply of rubberized metallic cord fabric having its end portions wrapped radially around said bead cores to form turnups which are axially displaced from the remaining portions of said carcass;
(d) an annular apex strip disposed between said carcass and each of said turnups, said annular apex strip extending radially of and from each of said bead cores and contacting said carcass along its axially inward surface; and (e) a cushion element of a soft rubber compound of high restorability having a coefficient of restitution of .55 to .65 and having a Shore A hardness of between 50°
and 65°, which Shore A hardness is less than that of the apex strip and carcass of said cushion element, enveloping the terminal edges of said turnups extending radially outwardly from between said apex strips and said turnups into said sidewalls and being of a material having a high adhesion to the metallic cords forming the carcass thereby isolating the terminal edge of each turnup from said carcass ply and rendering the bead and lower sidewall portions of said pneumatic tire more flexible to inhibit separation of said cords at said terminal edges.
2. The pneumatic tire in accordance with claim 1 further including reinforcement strips of rubberized metallic cord fabric wrapped about said bead cores and forming radially outward extensions of said turnups, said cushion elements enveloping the terminal edges of said reinforcement strips.
3. The pneumatic tire in accordance with claim 1 wherein the terminal edges of said turnups are axially spaced from said terminal edges of said reinforcement strips and each other in said cushion elements.
4. The pneumatic tire in accordance with claim 2 wherein said terminal edges of said turnups and said rein-forcement strips are positioned at the cross-sectional mid-point of said cushion elements.
5. The pneumatic tire in accordance with claim 2 wherein said cushion elements have a lentil cross-sectional configuration having at their thickest point, a width equal to a multiple of the diameter of said metallic cords.
6. The pneumatic tire in accordance with claim 1 wherein said cushion elements have a Shore A hardness of about 60°.
7. The pneumatic tire in accordance with claim 2 wherein said cushion elements are the vulcanization product of a compound comprising:
(a) about 20 to about 30 parts reinforcing carbon black;
(b) about 2.5 to about 3.5 parts sulfur;
(c) about 5 to about 10 parts active silicic acid;
(d) about 1 to about 3 parts resorcinol; and (e) about 1 to about 2.5 parts hexamethylene tetramine;
all being parts by weight based on 100 parts rubber.
(a) about 20 to about 30 parts reinforcing carbon black;
(b) about 2.5 to about 3.5 parts sulfur;
(c) about 5 to about 10 parts active silicic acid;
(d) about 1 to about 3 parts resorcinol; and (e) about 1 to about 2.5 parts hexamethylene tetramine;
all being parts by weight based on 100 parts rubber.
8. The pneumatic tire in accordance with claim 7 wherein said compound further includes zinc oxide, zinc stearate, processing oil, adhesive resin, antioxidants and antiozonants.
9. The pneumatic tire in accordance with claim 7 wherein said compound further includes accelerators.
10. The pneumatic tire in accordance with claim 1 wherein said cushion elements are formed from a mixture of natural rubber and butadiene rubber, with the natural rubber being present in quantities of 30 to 100 parts by weight of the mixture, and the butadiene rubber being present in quantities of 70 to 0 parts by weight.
11. The pneumatic tire in accordance with claim 10 wherein said butadiene rubber is cis-1,4-polybutadiene rubber.
12. The pneumatic tire in accordance with claim 10 wherein said natural rubber is present in quantities of at least 80 parts by weight.
13. A pneumatic tire according to claim 1 and having (a) a reinforcing belt assembly positioned between said tread portion and said carcass including at least two plies of rubberized metallic cord fabric; and (b) cushion elements of a soft rubber compound of high restorability enveloping the edges of said at least two plies.
14. The pneumatic tire in accordance with claim 13 wherein said cushion elements have a sickle cross-sectional configuration extending from said edges of said at least two plies, radially inwardly into said sidewalls, and having at its thickest point a thickness equal to a multiple of said cords in said plies.
15. The pneumatic tire in accordance with claim 13 wherein said cushion elements have a Shore A hardness less than that of said tread portion, sidewalls and said at least two plies.
16. The pneumatic tire in accordance with claim 13 wherein said cushion elements have a Shore A hardness of about 60°.
17. The pneumatic tire in accordance with claim 13 wherein said cushion elements are the vulcanization product of a compound comprising:
(a) about 20 to about 30 parts reinforcing carbon black;
(b) about 2.5 to about 3.5 parts sulfur;
(c) about 5 to about 10 parts active silicic acid;
(d) about 1 to about 3 parts resorcinol; and (e) about 1 to about 2.5 parts hexamethylene tetramine;
all being parts by weight based on 100 parts rubber.
(a) about 20 to about 30 parts reinforcing carbon black;
(b) about 2.5 to about 3.5 parts sulfur;
(c) about 5 to about 10 parts active silicic acid;
(d) about 1 to about 3 parts resorcinol; and (e) about 1 to about 2.5 parts hexamethylene tetramine;
all being parts by weight based on 100 parts rubber.
18. me pneumatic tire in accordance with claim 17 wherein said compound further includes zinc oxide, zinc stearate, processing oil, adhesive resin, antioxidants and antiozonants.
19. The pneumatic tire in accordance with claim 17 wherein said compound further includes accelerators.
20. The pneumatic tire in accordance with claim 13 wherein said cushion elements are formed from a mixture of natural rubber and butadiene rubber, with the natural rubber being present in quantities of 30 to 100 parts by weight of the mixture, and the butadiene rubber being present in quantities of 70 to 0 parts by weight.
21. The pneumatic tire in accordance with claim 20 wherein said butadiene rubber is cis-1,4-polybutadiene rubber.
22. The pneumatic tire in accordance with claim 20 herein said natural rubber is present in quantities of at least 80 parts by weight.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP2710446.7 | 1977-03-10 | ||
| DE19772710446 DE2710446A1 (en) | 1977-03-10 | 1977-03-10 | HEAVY DUTY STEEL CORD BELT TIRE, ESPECIALLY FOR TRUCKS AND OTHER HEAVY OR LARGE VEHICLES |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1100858A true CA1100858A (en) | 1981-05-12 |
Family
ID=6003285
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA297,296A Expired CA1100858A (en) | 1977-03-10 | 1978-02-20 | Heavy duty pneumatic tire |
Country Status (8)
| Country | Link |
|---|---|
| JP (1) | JPS53114105A (en) |
| AU (1) | AU515426B2 (en) |
| BE (1) | BE864707A (en) |
| CA (1) | CA1100858A (en) |
| DE (1) | DE2710446A1 (en) |
| FR (1) | FR2383028A1 (en) |
| GB (1) | GB1600068A (en) |
| SE (1) | SE7802340L (en) |
Families Citing this family (18)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2715734A1 (en) * | 1977-04-07 | 1978-10-19 | Uniroyal Ag | HEAVY-DUTY VEHICLE TIRES, IN PARTICULAR TUBELESS TIRES FOR TRUCKS OR DGL. |
| JPS55106806A (en) * | 1978-11-01 | 1980-08-16 | Ohtsu Tire & Rubber Co Ltd | Pneumatic tire |
| JPS5845366B2 (en) * | 1979-12-07 | 1983-10-08 | 株式会社ブリヂストン | Pneumatic radial tires with excellent high-speed durability |
| AU537267B2 (en) * | 1980-03-24 | 1984-06-14 | Goodyear Tire And Rubber Company, The | Carcass reinforcement for pneumatic tyre |
| US4273177A (en) * | 1980-03-31 | 1981-06-16 | Uniroyal, Inc. | Pneumatic radial tire with folded ply breaker having soft cushion surrounding breaker edge |
| JPS57182502A (en) * | 1981-05-01 | 1982-11-10 | Toyo Tire & Rubber Co Ltd | Pneumatic tire superior in durability of bead |
| JPS57191104A (en) * | 1981-05-17 | 1982-11-24 | Toyo Tire & Rubber Co Ltd | Radial tire for truck and bus |
| JPS58403A (en) * | 1981-06-24 | 1983-01-05 | Toyo Tire & Rubber Co Ltd | Radial tire good in bead durability |
| JPS58404A (en) * | 1981-06-24 | 1983-01-05 | Toyo Tire & Rubber Co Ltd | Steel radial tire good in bead durability |
| EP0192910B2 (en) * | 1985-02-26 | 1993-08-25 | The Goodyear Tire & Rubber Company | A pneumatic tire |
| JPS6312406U (en) * | 1986-02-15 | 1988-01-27 | ||
| US4842033A (en) * | 1987-11-16 | 1989-06-27 | The Goodyear Tire & Rubber Company | Pneumatic tire having gum strips encasing a carcass turnup |
| DE19652893A1 (en) * | 1996-12-19 | 1998-06-25 | Continental Ag | Pneumatic vehicle tires |
| JP3769090B2 (en) * | 1997-01-24 | 2006-04-19 | 東洋ゴム工業株式会社 | Pneumatic radial tire |
| FR3038545A1 (en) * | 2015-07-10 | 2017-01-13 | Michelin & Cie | PNEUMATIC COMPRISING ELASTOMERIC MIXTURES WITH LOW SULFUR CONTENT |
| CN110001303A (en) * | 2019-05-07 | 2019-07-12 | 江苏通用科技股份有限公司 | The strengthening course end construction of all-steel load-bearing radial tire |
| CN111993846B (en) * | 2020-08-24 | 2022-05-31 | 安徽佳通乘用子午线轮胎有限公司 | Small-size all-steel tire with high bearing performance |
| CN112026451A (en) * | 2020-09-08 | 2020-12-04 | 江苏通用科技股份有限公司 | Method for preventing bead ring from being placed wrongly |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3392773A (en) * | 1965-11-05 | 1968-07-16 | Firestone Tire & Rubber Co | Pneumatic tire |
| GB1276298A (en) * | 1968-07-23 | 1972-06-01 | Dunlop Holdings Ltd | Improvements in or relating to pneumatic tyres |
| FR2127163A7 (en) * | 1971-02-25 | 1972-10-13 | Kleber Colombes | Pneumatic tyre - has intermediate rubber layer between hard lip core and outer casing |
| JPS5225875B2 (en) * | 1972-06-01 | 1977-07-11 | ||
| GB1455243A (en) * | 1972-11-16 | 1976-11-10 | Dunlop Ltd | Pneumatic tyres |
| DE2313586A1 (en) * | 1973-03-19 | 1974-09-26 | Uniroyal Ag | VEHICLE AIR TIRES, IN PARTICULAR FOR TRUCKS |
| JPS5345961B2 (en) * | 1974-02-28 | 1978-12-11 | ||
| JPS51108401A (en) * | 1975-03-19 | 1976-09-25 | Bridgestone Tire Co Ltd | Rajiarutaiyano biidobukozo |
-
1977
- 1977-03-10 DE DE19772710446 patent/DE2710446A1/en active Granted
-
1978
- 1978-02-20 CA CA297,296A patent/CA1100858A/en not_active Expired
- 1978-02-22 AU AU33503/78A patent/AU515426B2/en not_active Expired
- 1978-03-01 SE SE7802340A patent/SE7802340L/en unknown
- 1978-03-02 GB GB8332/78A patent/GB1600068A/en not_active Expired
- 1978-03-09 JP JP2716878A patent/JPS53114105A/en active Pending
- 1978-03-09 BE BE185780A patent/BE864707A/en unknown
- 1978-03-09 FR FR7806825A patent/FR2383028A1/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| GB1600068A (en) | 1981-10-14 |
| AU515426B2 (en) | 1981-04-02 |
| DE2710446C2 (en) | 1988-11-03 |
| FR2383028A1 (en) | 1978-10-06 |
| FR2383028B1 (en) | 1984-02-17 |
| AU3350378A (en) | 1979-08-30 |
| BE864707A (en) | 1978-09-11 |
| SE7802340L (en) | 1978-09-11 |
| DE2710446A1 (en) | 1978-09-14 |
| JPS53114105A (en) | 1978-10-05 |
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