JPS5873406A - Pneumatic tire - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pneumatic vehicle tire, and in particular to a cap band reinforced with a belt and covering the same.
d) relates to a radial type tire having the following.

The expressions 1 radial tire and 1 radial tire, which are widely used in the pneumatic tire technology field, refer to at least one reinforcing ply of rubberized tire cord extending from bead to bead. Various tire constructions having a carcass or body having cords that are substantially radially oriented, i.e., such that the cords are oriented in the bead and substantially perpendicular to the crown centerline of the tire. can be said to mean. In single-ply radial tires, the cords of the carcass or body usually have a bias angle of 90'', i.e., in an unformed carcass, the cords run perpendicular to the plane of the bead.Two-ply radial tires In this case, the cords in each body ply are oriented at small, oppositely oriented angles, typically up to 10', with respect to the normal to the bead plane, in which case each body ply
It is said to have an oppositely oriented bias angle of .degree. or even larger (less than 90'). 4
Ply or heavier radial ply tire constructions typically employ similar opposing orientations of the cords within the tire line. All of these body or carcass structures are considered to be within the scope and meaning of the expressions "radial" and "substantially radial" as used herein.

Radial plies are generally constructed with a breaker or belt inserted between the crown zone of the carcass and the tread to reinforce the tread; such breakers are generally non-stretchable, i.e. metal wire, It consists of at least one layer or ply of tire cord or cable made of a similar material such as fiberglass, rayon, or the like. In a single-ply belt, the cord or tire has a relatively small bias angle of oo. That is, it is oriented in the plane of the bead of the tire and substantially parallel to the median equatorial plane ζ, ie, the crown centerline. If the belt has a multi-ply construction, cords or cables of similar but opposite small bias orientation at an angle generally within the range of about 25° to 30° relative to the mid-equatorial plane of the tire. It will be gradually adopted in plies.

It is already known that there are many types of tires, especially those whose treads are essentially parallel, as described above, made of non-extending cords or cousols, stacked and crossed over one another. Radial ply carcass tires reinforced by belts or breakers consisting of plies often fail at high speeds due to separation in the shoulder zone located at the edges of the belt plies of the tire. be. This separation of the plies occurs as the cord ends at the edge of the belt ply separate from the surrounding beam under the combined effects of centrifugal force acting on the tire, tire flexure, and heat buildup in the tire. There is a reason for becoming.

This result is due to the fact that the cord or cable in the belt ply, which is disposed obliquely to the median equatorial plane of the tire, is cut in the ply obliquely to the longitudinal direction of the cord or cousol in the ply. This is probably more likely due to the fact that the cut ends have a natural tendency to widen. The edge of the belt thus becomes a zone where the cut and free ends of reinforcing elements or cords or cables can cause damage to both the carcass plies and imms of the tire due to friction and by cutting.

Belt-reinforced radial tires of the type currently known in the art also have a tendency for the tire to meander in a direction perpendicular to the direction of motion of the vehicle on which it is mounted. There are also disadvantages in that the resulting tires are subject to excessive wear, premature failure and excessive vibration. This meandering occurs in tires that are vulcanized in undivided molds of the type currently known in the art, where the tire is inserted into the mold and then finally inflated. It seems that at least part of the reason lies in the fact that it takes shape. During such expansion of the tire in the mold, the cords or cables of said belts swing relative to each other, i.e. with a smaller bias than was originally oriented in the belt plies during the assembly operation. Pantograph in the corner (p
anto graph). However, due to internal tire stresses and uneven expansion of the tire strands, the cord cords or cables tend to pantograph unevenly, and the resulting uneven cord orientation produces the disadvantageous meandering described above. It is a cause that makes you feel bad.

The present invention is a belt-reinforced pneumatic tire for a vehicle wheel, the tire having at least two layers of belt plies of metal cords between the tread of the carcass and the crown zone, said cords being in each layer. The cords extend parallel to each other and then crosswise to the cords of each adjacent layer, said cords being at an angle of 16° and 30'' to the mid-equatorial plane of the tire.
, each said ply having a width approximately equal to the width of the tread, and said tire being inclined at an angle between said ply and said ply below said tread and radially outwardly relative to said metal cord belt ply. a cap band having at least one layer of fiber cords positioned therein, said cap band being formed by at least one layer of cords extending parallel to each other and to said median equatorial plane of the tire; having a width equal to or greater than the width of the plies, said fiber cords are capable of longitudinal elongation when stressed and have a width of about 1 ts from their respective unstressed state in the finished tire. 5 and the fiber cord should be below it.
Applying compressive stress to the dowels to help equalize the geometry and rolling properties of the tire and to limit separation of the belt plies due to radial outward movement of the coop under centrifugal force. is prestressed.

Use of the cap band allows the steel belt reinforced radial ply tire of the present invention to be vulcanized in an undivided mold rather than in a split mold as was previously necessary. It also makes it possible to The advantage of this is that even though the preformed raw tire is inserted into the mold, it is slightly smaller than the mold and is forced through the entire shape of the mold and then forced into the mold by the high internal pressure of the sulfuric fluid until the last approximately one inch. Even if the cap pan r has to be stretched between 5% and 5%, the steel belt cord tilted at a bias angle should be stretched as evenly as possible to the mid-equatorial plane so as to obtain as even a finished tire as possible. About 1
A desired final bias angle of between 6° and 30'' is obtained due to the fact that the pantograph ensures no meandering during running of the tire.

The invention will be more clearly understood from the following detailed description, taken in part from the accompanying drawings.

Reference is now made to Figure 1 of the accompanying drawings, which shows two superposed layers of radial carcass pliers or substantially radial carcass layers 3 and 5, covering respective lateral bands of the carcass and Each innermost edge has a pair of beads 11
and 13 terminating in the side walls 7 and 9, covering the two zones of carcass glue and joining the side walls 7 and 9 in their respective radially outermost zones, i.e. in the zones of the shoulders 17 and 19 of the tire. a tread 15, two layers of belts 21 and 23 superimposed on each other and both interposed between the crown zone of the carcass and the tread to reinforce the same; a carcass or body; a fluid-impermeable liner 25 radially inward of the belt ply 3 and extending from the belt ply 13 to the bead 13; and a single layer cap band interposed between the radially outermost belt ply 23 and the tread 15. 27 is shown.

Radially outwardly describing the cord ply components of this tire, body plies 3 and 5 are rubber made of any suitable natural or synthetic fiber such as nylon, rayon, polyester, metal wire fiberglass, etc. A layer of pull cord or cable. For the body plies shown, the cool r in each body ply is about 10 relative to the true radial plane.
and are normally oriented at equal small angles, such that each body ply has opposite bias angles of between 80° and 90° with respect to the mid-equatorial or central circumferential plane. 8 belts having 21
and 23 are parallel parallels which may be either laminar, i.e. in the form of a flat strip or band with rounded edges, or thread-like, i.e. in the form of a generally round wire or cable. layers of bimmed metal reinforcing elements, preferably steel, and these plies have a width approximately equal to the tread 15. The straw steel reinforcing elements of each ply are approximately 16° and 30" relative to the tire's mid-equatorial plane.
A cap band 21 overlaid on a radially outermost belt ply 23 oriented at a substantial bias angle between and the fiber cords or cables are oriented at a bias angle of substantially 00, ie substantially parallel, to the midline equatorial plane of the tire. cap band 2
7 is at least as wide as the widest of said belt plies 21 and 23 and preferably about 20 to 60 millimeters wider than said belt ply, ie 10 to 30 millimeters on one side of the belt.

Referring now to FIG. 2, there is shown schematically a scaled side view of the cap band 27 shown in FIG. 1. It should be noted that the cap band 27 is constructed of a single layer of the aforementioned cotton fibrous material, and that there is a certain degree of selected overlap and corresponding edge overlap between the ends 27a and 21.5 of the band 27. There must be adhesion of the parts.

The function of the splicing and gluing of the end portions of the cap band 2T is to minimize slippage of the band ends 27a and 27b relative to each other during inflation of the tire into the mold of the vulcanizing press. However, despite the overlap of ends 27a and 27b, it has been found that the use of a single layer cap band results in a moderate degree of slippage in the splice overlap of the same band during expansion in the mold. be. This slippage causes the tread 15 to stretch unevenly in the zone covering the splice overlap and creates a depression across the tread from shoulder 17 to shoulder 19. It may also cause at least one of the steel cutters 23 and 21 to pantograph somewhat unevenly in the region of the cap band splice overlap, with attendant meandering problems. Such slippage will cause the tire to be out of round in the slip zone and will cause at least one of the steel breaker plies to narrow in the same zone.

Referring now to FIG. 3, there is shown schematically a side view of a second embodiment of a cap band 28 according to the present invention, which cap band is used during final inflation in a tire mold. The tire cap band shown in FIG. 1 may be advantageously substituted when it is desired to further minimize slippage in the end portions of the tire. The cap band 23 shown in FIG. 3 consists of two rubber bands of parallel ply fiber cord or cable made from a single fiber material wrapped in a spiral around the crown portion of the tire a little more than two times. It is composed of a pulling layer. In this structure, both ends 28a and 28b of the band overlap band 2.
9, in which the outer end of the band and the inner end of the band are adhered to opposite sides of the continuous central layer of the band.

The overlap band 29 is thus reinforced by the continuous central layer of the band and slippage of the ends 28a and 28b relative to each other is eliminated. The tread 15 thus extends more evenly above the overlap zone and the belt ply 23 becomes narrower when the single layer cap band of FIG. 2 is used below the overlap zone of the FIG. 3 embodiment. It should be noted here that regardless of whether a single layer or two layer cap band is used, the cap band will inject the same selected amount into the underlying belt ply. It is desirable to apply compressive stress. It has been found to be advantageous to achieve this objective only when a single layer cap pan is employed when a two layer cap band with cords or cables of similar physical properties is employed. The idea is to use half a parallel fiber cord or cable per transverse dimension. For example, if a single layer cap pan r is used, the appropriate compressive stress is such that the cap band has a width of 1
It has been found that when constructed with 9.5 cords per centimeter (24 per inch), they are applied to the underlying belt ply.

If a two-layer spirally wound cap band is used, a band constructed of 1 cm wide (12) cords per inch is appropriate. Alternatively, the physical properties of the cords or cables within the two-layer cap pan can be selected such that various other numbers of cords are required per unit width dimension, and such selection is within the art. performed well within the ordinary skill of

Referring now to FIG. 4, there is shown schematically an undivided mold 40 of the type well known in the art. Such a mold essentially has a lower mold part 42 and an upper mold part (not shown). The inner surface of the mold carries a plurality of ridges or similar protrusions, indicated by dash-dotted lines 44 in FIG. 4, to form grooves in the tire tread. Since this mold is of the undivided type as described above, it is clear that the preformed tire 46, commonly referred to in the art as a "second stage carcass", can be easily inserted into the mold 40. The outer radius (R1') must be smaller than the inner radius of the groove forming protrusion to a certain extent so that it can be inserted into the groove forming protrusion.

The second stage carcass is therefore somewhat smaller than the carcass that will eventually arrive when fully expanded into the mold. As shown, the mold has an inner radius (R2) approximately 1-5 inches larger than radius (R1).

After the preformed tire 46 is inserted into the mold number 40 and the beads 48 are properly placed, the mold is closed and a high pressure heated fluid such as steam or hot water is allowed to enter a vulcanization bag (not shown). is applied, causing the carcass 46, and thereby the carcass 46, to expand radially outward until the peripheral surface 50, or tread, of the carcass contacts the inner surface of the mold.

Other advantages are obtained by using a cap band constructed by at least a single layer of cords that are longitudinally extendable and oriented at a substantially 0° angle to the midline equatorial plane of the tire. is undergoing final expansion in this mold. It should be noted that in manufacturing a belt-reinforced tire as contemplated by the present invention, the carcass is assembled into a substantially flat or cylindrical shape and then shaped into a toroid, over which the belt ply is applied. , the unstressed cap pan P and the tread rim thereon are attached to the crown zone of the preformed carcass to complete the raw tire. Of course, as mentioned above, the raw tire has an outer diameter that is smaller than the inner surface diameter of the mold to some extent. Therefore, the belt cord will be pantographed to a degree that may become uneven if not properly adjusted during the final inflation of the tire in the mold. However, during such final inflation of the tire, the cords of the cap band extend longitudinally to the same extent, i.e., between about 1 inch and 5% of their respective unstressed initial lengths, and preferably Approximately 1
% and 3%, and since each is close to the belt ply, a restraining force is applied to the metal cord of the belt ply, so that the belt cord pantographs as evenly as possible. It is designed to ensure that The significance of this feature is to minimize the tendency of the belt cord to pantograph unevenly, thereby preventing the final tire from becoming sufficiently uneven to cause the tire to meander excessively during driving and possibly cause premature failure. After the molding cycle is completed, the still hot tire is removed from the press and loaded onto a post-expansion chuck, where the tire is only made available for further processing. When fully cooled, it is expanded to a pressure of about 2.1 to 3.5 kilograms per square meter (30 to 50 pounds per square inch). This post-inflation process not only ensures that the single tire will maintain a uniform shape during the cooling period, but also ensures that the cords of the cap band 2T are aligned longitudinally during final inflation in the tire mold. It also ensures that the prestress applied to the cord by stretching will be maintained. The cap band cords will therefore provide the desired radially inward compressive stress on the belt plies of the tire even after the end of the post-inflation process, thus significantly assisting in keeping the tire as even as possible. There are also many other benefits to prestressing the cap band cord. For example, at high speed,
The internal structure of a belt-reinforced tire can be affected by belt strain, creating standing waves that can cause premature tire deterioration. Cap band 27 tends to avoid this problem due to its compressive action. The cap band also avoids the risk of belt ply separation that would occur at high speeds due to the action of centrifugal force if the pan r were not used. Of course, for this purpose the cap band should be at least as wide as the widest belt ply, and preferably, so that the cap pantoco-P constantly forces the side edges of the widest belt ply to deflect towards the carcass. must have a width that is somewhat larger than that.

Although the Pertonolite 21 and 23 have been described above as primarily utilizing cords of steel or similar materials as reinforcing elements, it should be understood that the principles of the present invention also apply to cords of other materials such as rayon, fiberglass, fiber B1, and similar materials. It is also applicable to belts having cords of high elasticity material incorporated therein.

[Brief explanation of the drawing]

FIG. 1 is a partially cross-sectional perspective view of a radial ply tire reinforced with a cap pan 1F according to an embodiment of the present invention, and FIG. tJ/E2 is a cap shown in FIG. 1. FIG. 3 is a side view schematically showing the band on a smaller scale than in the same figure; FIG. FIG. 4 is a schematic diagram of a tire and mold showing the final inflation of the tire inside the mold in accordance with the present invention. 1... "Pneumatic tire", 15...
"Tren F", 21.23... "At least 2 plies of belt cord", 27... "Cap Pan R". Agents Asamura and Kōgai 2 people Cleaning of the drawings (no change in content) Procedural amendment (method) % formula % 1. Display of the case Showa! 7 year patent application No. 1ρ/j? ,! t, No. 3, Relationship with the case of the person making the amendment Patent applicant 4, Agent 5, Supplementary 1F order date: 59th July 1939 6, Number of inventions increased by the amendment 7, Subject of the amendment Drawing J, hanging...! + (Within, no structural changes) 8. Details of amendments as attached.

Claims (1)

[Scope of Claims] (1) A radial silica carcass, a tread on the crown zone of the carcass, and the tread and the crown zone in a relationship circumferentially surrounding the crown zone of the carcass. and the belt inserted between the
The belt has at least two layers of Peltoco-P of high modulus material, and the belt cords extend parallel to each other in each belt ply and intersect with the cords of the next adjacent belt ply, and each The belt cord of the belt ply is approximately 16° and approximately 30° relative to the median equatorial plane of the tire.
a pneumatic tire having a pneumatic tire tilted at an angle between a cap band having at least one fiber cord in contact with and circumferentially surrounding the ply and interposed between the ply and the tread;
the cap band has a width at least equal to the width of the widest of the belt plies, and the fiber cores in the cap band are substantially parallel to each other and to the midline equatorial plane of the tire. and the fiber cords within the cap band are each prestressed by being stretched by about 11 to about 5% from an unstressed state to provide uniformity to the tire's geometrical properties and performance. 1. A pneumatic tire, characterized in that said belt is subjected to compressive stress to maximize its performance. (2. The pneumatic tire according to claim 1,
A pneumatic tire wherein the fiber cords are stretched by about 1% to about 3% from their respective unstressed states. (6) A pneumatic tire according to claim 1,
A pneumatic tire characterized in that the fiber cords are stretched by about 31 degrees from their respective unstressed states. (4) A pneumatic tire according to claim 1, wherein said cap band has two layers of fiber cords formed from only one helically wound fiber material, each said layer the fiber cords are substantially parallel to each other and to the median equatorial plane of the tire and are pre-stretched in the longitudinal direction by being stretched by about 1 ts to about 5 inches from an unstressed state of the fiber-oriented fiber cord P. Pneumatic tires characterized by being stressed.