JP2012245829A - Pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pneumatic tire which can be inexpensively and easily manufactured, and which uses a reinforcing member capable of utilizing end materials conventionally discarded, for actualizing desired reinforcing effects while satisfying the basic performance as the tire.SOLUTION: The pneumatic tire includes pairs of right and left bead parts 11 and sidewall parts 12, and a tread part 13 ranging between both sidewall parts. The reinforcing member 5 made of reinforcing fibers subjected to plating or adhesive treatment and a rubber covering the reinforcing fibers is annularly disposed at least in a portion of each sidewall part in a tire peripheral direction. The reinforcing fibers are oriented to the sidewall part substantially in a tire radial direction, at least one end of each reinforcing fiber is terminated within the reinforcing member, and at least portions of projection parts where the reinforcing fibers are projected in a direction perpendicular to the reinforcing member, intersect each other.

Description

  The present invention relates to a pneumatic tire (hereinafter, also simply referred to as “tire”), and more particularly to a pneumatic tire according to an improvement of a reinforcing member.

  Conventionally, in a pneumatic tire, reinforcement has been carried out by arranging a reinforcing member formed by aligning organic fiber cords or steel cords in a certain direction and rubberizing at each part from the bead portion to the tread portion. It has been broken. For example, Patent Document 1 discloses that a side reinforcing layer formed by impregnating a rubber component in an organic fiber cord is disposed between a carcass layer and a belt layer of a sidewall.

  Further, as an improved technique for reinforcing the sidewall portion, for example, Patent Document 2 discloses a pneumatic radial tire in which a fiber reinforcing member in which a nonwoven fabric made of monofilament fibers is covered with rubber is installed in the vicinity of the carcass layer. Patent Document 3 discloses a pneumatic radial tire in which a reinforcing layer formed by covering a nonwoven fabric with rubber is provided inside and outside the radial width of the radial carcass, and the radial carcass is sandwiched between these reinforcing layers. It is disclosed. Furthermore, Patent Documents 4 and 5 disclose pneumatic safety tires in which rubber-filament fiber composites are disposed on the sidewall portions in order to improve run-flat running performance.

JP 2006-142877 A (Claims etc.) JP-A-8-40023 (Claims etc.) JP 2002-331808 A (Claims etc.) JP-A-11-129712 (Claims etc.) Japanese Patent Laid-Open No. 11-240307 (claims, etc.)

  However, the reinforcement member generally used in the past is made of a rubber composite material in which organic fibers or steel single wires or twisted cords are aligned in a certain direction. However, there was a difficulty that it took a lot of man-hours.

  In addition, since the cord cut surfaces that do not have an adhesive action with the rubber are arranged at regular intervals at the end portion of the reinforcing member, the cut surfaces serve as a starting point for the separation of the cord and the rubber, resulting in a rough road. There is also a problem that there is an unavoidable risk of separation starting from the end of the reinforcing layer due to running or heavy load running. On the other hand, in the manufacturing process of tires, when manufacturing belts, carcasses, etc., the ends of organic fibers or steel single wires or twisted cords remain with a half length. Since regular arrangement is indispensable, such a half-length end material cannot be used and must be disposed of.

  Therefore, the object of the present invention is to solve the above-mentioned problems in the conventional reinforcing member, and can be manufactured inexpensively and easily, and it is possible to utilize the scrap material that has been discarded in the past. An object of the present invention is to provide a pneumatic tire that achieves a desired reinforcing effect while satisfying the basic performance as a tire by using a simple reinforcing member.

  As a result of intensive studies, the present inventor can obtain a desired reinforcing effect at low cost and without impairing tire performance by using a reinforcing member having a specific structure using a reinforcing fiber that satisfies a predetermined condition. In addition, the inventors have found that it is possible to contribute to the utilization of mill ends and have completed the present invention.

That is, the present invention is a pneumatic tire having a pair of left and right bead portions and sidewall portions, and a tread portion continuous between both sidewall portions.
A reinforcing member comprising a reinforcing fiber plated or adhesive-treated and a rubber covering the reinforcing fiber is disposed annularly in the tire circumferential direction on at least a part of the sidewall portion. The fibers are oriented substantially in the tire radial direction in the sidewall portion, at least one end of the reinforcing fiber terminates in the reinforcing member, and the reinforcing fiber is projected in a direction perpendicular to the reinforcing member. The projection units are characterized in that they intersect at least partially.

The tire of the present invention preferably has a carcass made of at least one carcass ply extending in a toroidal shape across the pair of bead portions, and the carcass ply is made of the reinforcing member. . In this case, the basis weight density of the reinforcing member is preferably 100 g / m ² or more and 1500 g / m ² or less, and the length of the reinforcing fiber is preferably within a range of 5 mm to 50 mm. Is preferably in the range of 0.07 mm to 0.34 mm.

The tire of the present invention has a carcass made of at least one carcass ply extending in a toroidal shape across the pair of bead portions, and has at least one of the sidewall portions outside the carcass ply. It is also preferable that the reinforcing member is disposed in the region of the portion. In this case, the basis weight density of the reinforcing member is preferably 300 g / m ² or more and 1500 g / m ² or less, the length of the reinforcing fiber is preferably 15 mm or more, and the diameter of the reinforcing fiber is Preferably it is in the range of 0.07 mm to 0.60 mm.

  In the tire of the present invention, an inorganic fiber can be suitably used as the reinforcing fiber.

  According to the present invention, by using the above-described configuration, the tire member can be manufactured inexpensively and easily compared to the conventional one, and the tire performance is not impaired by using the reinforcing member that can utilize the end material. It has become possible to obtain a pneumatic tire that achieves a desired reinforcing effect.

It is a width direction one side sectional view showing an example of the pneumatic tire of the present invention. It is a schematic diagram which shows an example of the reinforcement member which concerns on this invention. It is a width direction one side sectional view showing other examples of the pneumatic tire of the present invention. (A), (b) is explanatory drawing which shows the state of the protrusion input with respect to a tire side part. It is a graph which shows the difference in the effect with respect to protrusion input of the case where the length of a reinforcing fiber is short (a) and the case where it is long (b). It is a schematic diagram which shows the dispersion state of the reinforcing fiber in a comparative example.

Hereinafter, embodiments of the present invention will be described in detail.
In FIG. 1, the cross-sectional view of the width direction of an example of the pneumatic tire of this invention is shown. The illustrated pneumatic tire includes a pair of bead portions 11, a pair of sidewall portions 12 connected to the bead portions 11, and a tread portion 13 straddling the both sidewall portions 12, and these portions are embedded in the bead portion 11. In addition, at least one carcass 2 consisting of two carcass plies in the illustrated example is provided to reinforce between the pair of bead cores 1. Further, two belt layers 3 arranged so as to cross each other and a belt reinforcing layer 4 arranged so as to cover the entire width thereof are arranged outside the crown portion tire radial direction of the carcass 2. . Further, a bead filler 6 is disposed outside the bead core 1 in the tire radial direction.

  The tire according to the present invention is characterized in that a reinforcing member composed of reinforcing fibers and rubber covering the tire is disposed on at least a part of the sidewall portion 12 in an annular shape in the tire circumferential direction. FIG. 2 is a schematic view showing an example of a reinforcing member according to the present invention. This figure shows a dispersion state of the reinforcing fibers when viewed from a direction perpendicular to the surface of the reinforcing member. As shown in the figure, the reinforcing member according to the present invention includes reinforcing fibers 21 plated with adhesive or an adhesive and rubber 22. Further, the reinforcing fiber 21 is oriented in one direction as shown, and at least one end thereof terminates in the reinforcing member, that is, has a length that does not continuously extend between the widthwise ends of the reinforcing member. Made of short fibers. Further, as shown in the drawing, the reinforcing fiber 21 is embedded in the rubber 22 so that a projected portion obtained by projecting the reinforcing fiber 21 in a direction perpendicular to the reinforcing member intersects at least partially. The reinforcing member according to the present invention has a planar shape having a thickness.

  By adopting such a configuration, it has become possible to use the end material that has conventionally become waste as the reinforcing fiber 21 of the reinforcing member, and it has become possible to effectively use the waste material. In addition, unlike the conventional cord reinforcing layer, the reinforcing member according to the present invention does not require a process such as a stranded wire or draw rolling, and thus is easy to manufacture, and is excellent in cost. ing. Furthermore, in the reinforcing member according to the present invention, since the cross-sections of the reinforcing fibers do not line up at the end portions, there is no problem of separation starting from the reinforcing member end portions.

  In the present invention, as shown in the drawing, a reinforcing member in which the reinforcing fibers 21 are substantially oriented in one direction is used, and this reinforcing member is used so that the orientation direction of the reinforcing fibers 21 in the sidewall portion is the tire radial direction. To place. In this way, by using the reinforcing member in which the reinforcing fibers 21 are substantially oriented in the tire radial direction, as described later, the use as a carcass ply, or the reinforcement disposed outside the carcass ply in the side wall portion. In the use as a layer, the desired effect can be obtained. Here, in the present invention, the fact that the reinforcing fibers 21 are substantially oriented in the tire radial direction means that a certain degree of distribution occurs in the orientation direction of the reinforcing fibers 21 in the production of the reinforcing member. It means that an error range is included. Specifically, for example, the angle formed by the orientation direction of the reinforcing fibers 21 with respect to the tire radial direction is a range of about ± 10 °.

  In the present invention, the reinforcing member can be applied to a carcass ply. The reinforcing member is applied to the carcass ply, that is, the reinforcing member is used instead of the rubber-coated member of the reinforcing cord made of a twisted cord of organic fiber or steel fiber, which has been conventionally used as a carcass ply. As a result, it becomes possible to apply the waste material to the carcass ply, so that the product cost can be greatly reduced.

  The carcass ply is a skeletal member that functions as an internal pressure container of the tire, and the carcass ply is balanced with the internal pressure by exerting tension, and thus is one of the most important members in a pneumatic tire. In consideration of safety, it is necessary to be able to maintain an internal pressure several times that of normal use. For example, in a passenger car tire, the carcass ply needs to be able to hold an internal pressure of 1.5 MPa or more, and in a heavy duty tire such as a truck / bus, it needs to be able to hold an internal pressure of 2.0 MPa or more. Is done. Of particular importance as a carcass ply material is tensile strength, which is indispensable for continuing to increase the internal pressure and clearing the hydraulic test that evaluates how many times the internal pressure will cause the tire to break It is a condition. In addition, expandability during tire molding is also important. Therefore, the carcass ply material requires high rigidity and strength in the tire radial direction and expandability (moldability) in the tire circumferential direction. In the present invention, since the reinforcing fibers 21 are substantially oriented in the tire radial direction, the rigidity and strength in the tire radial direction are not greatly affected by the density (weight density) of the reinforcing fibers 21 or the fiber length. In addition to being able to ensure, the rigidity in the tire circumferential direction can be kept low, and the expandability that can withstand molding can also be satisfied.

In the present invention, when the reinforcing member is applied to a carcass ply, the reinforcing member has a weight density of 100 g / m ² or more and 1500 g / m ² or less, particularly 600 g / m ² or more and 900 g / m ² or less. It is preferable to use it. If the basis weight is less than 100 g / m ² , the strength of the reinforcing member may be insufficient. On the other hand, when the fabric density exceeds 1500 g / m ² , expandability and moldability deteriorate. Here, in the present invention, the basis weight density of the reinforcing layer 3 means the total weight of reinforcing fibers per unit area in one layer of reinforcing member. That is, the total weight (g) of the reinforcing fibers 21 per layer of the reinforcing member included in the unit area (1 m ² ) is the basis weight in the present invention.

  When the reinforcing member is applied to a carcass ply, a reinforcing fiber having a length of preferably 5 mm to 50 mm, more preferably 25 mm to 40 mm is used. Moreover, it is preferable that the diameter exists in the range of 0.07 mm-0.34 mm, especially 0.15 mm-0.25 mm. If the length of the reinforcing fiber is too short, the number of man-hours for cutting increases. If the length is too long, the moldability in the expansion process after the green tire is molded deteriorates. In addition, if the diameter of the reinforcing fiber is too small, the cost in the wire drawing process for obtaining a thin wire diameter increases, and the number of reinforcing fibers to be spread increases, resulting in an increase in cost. On the other hand, if the diameter of the reinforcing fiber is too large, the bending stiffness increases and the longitudinal spring increases, the bending fatigue property deteriorates, and the reinforcing fiber may break during running at low internal pressure.

  In the present invention, it is not necessary for all the reinforcing fibers used for the reinforcing member to have a single length and diameter, and a mixture of reinforcing fibers having a plurality of types of lengths and diameters may be used. It is preferable to use a material having a length and diameter within the above range. In particular, if the length of the reinforcing fiber is too long, the uniformity of the reinforcing member is impaired, which is not preferable because the uniformity of the tire shape and the tire rigidity in the circumferential direction, which is a component that determines uniformity, is deteriorated. In addition, the cross-sectional shape of the reinforcing fiber is basically circular, but a polygonal shape such as an ellipse or a triangle may be used.

  In the present invention, the reinforcing member may be disposed in at least a part of the sidewall portion outside the carcass ply. FIG. 3 shows a cross-sectional view in the width direction of another example of the pneumatic tire of the present invention. In the illustrated pneumatic tire, the reinforcing member 5 is disposed in a region from the end of the belt layer 3 to the vicinity of the winding end 2a of the carcass ply. By arranging the reinforcing member in at least a part of the side wall portion, it is possible to improve the side cut resistance, and particularly, even when the ply structure is simplified for weight reduction of the tire, A significant decrease in side cut resistance can be suppressed.

  In other words, by simplifying the ply structure by reducing the number of two carcass plies to one, or by lowering the carcass ply winding height, in addition to reducing the weight of the tires, the direct material cost, molding man-hours, etc. In this case, however, there is a concern that the strength of the ply is insufficient. In particular, since the carcass ply resists the projection input by a high tension, there is a concern that the cutting performance at the side portion may be significantly reduced due to the lack of this strength. FIG. 4 is an explanatory view showing a state of projection input to the tire side portion. As shown in the figure, when the tire side portion receives an input of the protrusion 20 from the road surface or curbstone, the carcass ply may break down due to the sharp protrusion whose tip R is 20 mm or less. Many. The reason is that, as shown in FIG. 4 (a), when the projection 20 is pushed into the tire, a tensile stress acts locally on the carcass ply, and this stress exceeds the strength of the ply cord. Then, the carcass ply will break. On the other hand, as shown in FIG. 4B, by arranging the reinforcing member 5 outside the carcass ply, the reinforcing member 5 efficiently shares the tension applied to the carcass ply when the protrusion 20 penetrates. This makes it possible to prevent the carcass ply from being broken. Therefore, in this case, the reinforcing fiber preferably has the same strength as the carcass ply.

  Further, the length of the reinforcing fiber is preferably 15 mm or more, more preferably 20 mm or more, and the upper limit is not particularly limited as long as it is up to the height of the sidewall portion of the applied tire, Especially preferably, it shall be in the range of 25 mm-40 mm. If the length of the reinforcing fiber 5 is too short, the penetration of the projection cannot be wrapped when the projection 20 is input, and the carcass ply 2 cannot be protected from local tension, and the ply cord may be broken. Further, the effect of improving the side cut resistance is reduced (see FIG. 5A). On the other hand, if the length of the reinforcing fiber is 15 mm or more, the effect can be exhibited even for sharp projection input (see FIG. 5B). Note that the tension generated in the carcass ply is not local to the protrusion having R of 20 mm or more. Therefore, since the frequency of breakage of the carcass ply is reduced, here, a case is assumed in which the tip R has a radius of 20 mm or less.

In the present invention, when the reinforcing member is used for side reinforcement, a reinforcing member having a basis weight density of 300 g / m ² or more and 1500 g / m ² or less, particularly 450 g / m ² or more and 900 g / m ² or less is used. It is preferable. If the basis weight is less than 300 g / m ² , the strength of the reinforcing member may be insufficient. On the other hand, when the fabric density exceeds 1500 g / m ² , expandability and moldability deteriorate.

  Moreover, when using the said reinforcement member for side part reinforcement, it is preferable to use a thing within the range whose diameter is 0.07 mm-0.60 mm as a reinforcement fiber, especially 0.12 mm-0.34 mm. If the diameter of the reinforcing fiber is too small, the cost in the wire drawing process for obtaining a thin wire diameter increases, and the number of reinforcing fibers to be spread increases, resulting in an increase in cost. On the other hand, if the diameter of the reinforcing fiber is too large, the bending fatigue property is deteriorated, and the reinforcing fiber may be broken due to compressive deformation during traveling at a low internal pressure.

  When the reinforcing member is arranged on the sidewall portion, the arrangement region may be at least a part of the region from the end portion of the belt layer 3 to the vicinity of the upper end of the bead core 1. Place it throughout. Thereby, the cut resistance of the whole side wall part can be improved.

  In the present invention, any material may be used as the reinforcing fiber, and it can be appropriately selected from various materials usually used for tire reinforcing members. Specifically, for example, inorganic fibers include metal fibers such as steel filaments and glass fibers, and organic fibers include aromatic polyamide fibers, fatty acid polyamide fibers, polyester fibers, polyparaphenylenebenzeneoxazole fibers, and polyvinyl alcohol-based synthetics. Examples thereof include fibers and carbon fibers. In the present invention, among the above, it is preferable to use inorganic fibers, particularly steel filaments, as the short fibers.

  The above-mentioned reinforcing fibers made of inorganic fibers or organic fibers are used in the manufacturing process of tire reinforcing cords, such as end materials (waste made from residual yarn) generated in the post-plating wire drawing process or stranded wire process, It can be manufactured from mill ends generated in the cord rolling process. In the present invention, since such a conventionally discarded scrap material can be used, the cost can be greatly reduced as compared with the conventional one, and the waste can be reduced. is there.

  That is, a metal cord such as a steel cord is manufactured by unwinding a filament from a plurality of reels around which a single filament wire having been plated is wound, and twisting the filament bundle using tension. A non-metallic cord made of organic fibers or the like is manufactured by performing a dipping process in which an adhesive is applied to a twisted filament bundle. When manufacturing a metal twisted cord, when any one of the reels is emptied, the remaining filaments are discarded even if they remain on the other reels. Also, the adjustment portion at the end of the cord is discarded when the manufacturing process is stopped for adjustment and then restarted. Furthermore, since both the metal cord and the non-metallic cord use the tension to manufacture the reinforcing member, the cord end portion that cannot physically secure the tension is also discarded. In the present invention, the reinforcing member can be formed by effectively using the end material of the cord generated in each process in manufacturing the tire.

  In addition, the technique which improves on-ice performance by containing the very micro fiber about 5.0 mm or less in length, usually 2 mm-3 mm in a tread rubber as a short fiber is known well conventionally. However, in consideration of the effective use of the waste material as described above, if the end material of the cord is cut into micro short fibers and used, the number of manufacturing steps and cost increase. In the present invention, if the reinforcing fibers to be used do not have a certain length and basis weight, the reinforcing fibers do not intersect with each other, or even if they intersect, a sufficient reinforcing effect on strength and rigidity cannot be obtained. Therefore, it is preferable to use a reinforcing fiber having the above length, basis weight density, and the like. However, if only short reinforcing fibers or only long reinforcing fibers are used, a sufficient reinforcing effect may not be obtained or there may be a problem in durability.

  Moreover, since the said reinforcing fiber is embed | buried in rubber | gum and forms a reinforcement member, in order to ensure adhesiveness with rubber | gum, it needs to be plated or adhesive-treated. That is, in the present invention, when the reinforcing fiber is a metal fiber, a plated one is used, and when the reinforcing fiber is an organic fiber, an adhesive-treated one is used. In a metal fiber such as a steel filament, for example, when general Cu + Zn plating is performed, Cu during plating plays a role of adhering rubber and reinforcing fiber when forming a reinforcing member. When the surface of the metal cord is not plated, the rubber and the reinforcing fiber are easily peeled off, and there is a concern that the progress of peeling easily occurs along the reinforcing fiber. Accordingly, in the present invention, when metal fibers are used as the reinforcing fibers, it is necessary to use plated ones, and even when a stranded wire cord is used as a raw material, single wires must be plated. is there. When the metal cord is made of a copper wire, the copper wire itself has an adhesive effect, so that plating is not necessary. In addition, in the case of non-metallic cords made of organic fibers, etc., by using an adhesive dipped in accordance with a conventional method, as with plated metal cords, adhesion to rubber is ensured. Is possible.

  Here, there is no restriction | limiting in particular as plating provided in the metal fiber surface as a reinforcement fiber, Brass, bronze, Cu, Zn plating, etc. may be sufficient. In particular, when the above-mentioned waste scraps are used as the reinforcing fibers, since these are already plated, there is an advantage that good adhesion to rubber can be obtained without further plating.

  The rubber used for the reinforcing member can be appropriately selected from rubber types conventionally used for tire reinforcing member applications, and is not particularly limited. Moreover, there is no restriction | limiting in particular about the thickness of reinforcement member itself, Although it can determine suitably according to the target reinforcement performance, For example, it can be set as 0.5 mm-3.0 mm. This is because the thickness of the thinnest reinforcing layer 3 assumed when applied to a tire for a passenger car is 0.5 mm, whereas the thickness of the thickest reinforcing layer 3 assumed when applied to a heavy load tire is 3. It means 0 mm.

The reinforcing member in which the reinforcing fibers are oriented substantially in one direction as described above can be manufactured, for example, as follows.
That is, first, a sheet of unvulcanized rubber having a predetermined thickness is prepared, and a bundle of reinforcing fibers cut to a predetermined length is entirely transferred onto the rubber sheet from a predetermined amount and a predetermined height on the rubber sheet. Drop to a uniform density. At this time, a guide body having a portion that opens in the vertical direction above the rubber sheet, has a width along the longitudinal direction of the rubber sheet that is narrower at the lower end than the upper end, and gradually decreases from the upper end toward the rubber sheet. The reinforcing fiber is dropped on the rubber sheet through the guide body. As a result, the reinforcing fibers fall on the rubber sheet in a state of being oriented in the width direction of the rubber sheet along the shape of the lower opening of the guide body, so that the reinforcing fibers are substantially oriented in one direction. The reinforcing member which is made can be obtained. The guide body also has an effect of preventing the density of the reinforcing fibers that are blown off from being dispersed more widely than necessary, and can be designed according to the width of the rubber sheet disposed below. In particular, the guide body preferably has a portion where the width does not vary following the portion where the width along the longitudinal direction of the rubber sheet gradually decreases, thereby more reliably orienting the reinforcing fibers. be able to.

  Next, an unvulcanized rubber sheet is placed on the dropped reinforcing fiber, whereby a reinforcing member in which the reinforcing fiber is embedded in the rubber can be manufactured. At this time, by moving the lower rubber sheet in one direction at a predetermined speed, the density of the reinforcing fiber in the reinforcing member can be determined by the ratio of the amount of the reinforcing fiber falling and the moving speed of the rubber sheet. it can.

  Here, as a method for dropping the predetermined amount of reinforcing fibers, a bundle of reinforcing fibers cut in advance is transported by a belt conveyor or the like and dropped onto a predetermined portion on the rubber sheet, as well as uncut. A method of dropping the reinforcing fiber while cutting may be used. In the latter case, the work of untangling the reinforcing fibers and the work of supplying a bundle of reinforcing fibers in a constant amount at a constant time are not required, and therefore the reinforcing member can be manufactured more efficiently.

  Since the reinforcing member according to the present invention can be easily manufactured in one process as described above, it is easier to manufacture and consumes less energy than a conventional reinforcing member that requires a large number of steps for manufacturing. There is an advantage that the manufacturing cost is low.

  In the tire of the present invention, it is only important that the reinforcing member is arranged such that the orientation direction is the tire radial direction, and other details of the tire structure and the material of each member are not particularly limited. It can be configured by appropriately selecting from conventionally known ones.

  For example, the belt layer 3 is formed by rubberizing steel cords arranged in parallel at a predetermined angle with respect to the tire circumferential direction, and it is necessary to provide at least one layer. They are arranged in two layers. Further, as shown in the figure, the carcass is folded around the bead core 1 from the tire inner side to the outer side and locked. Further, the belt reinforcing layer 4 is composed of a rubberized layer of reinforcing cords arranged substantially parallel to the tire circumferential direction, and is arranged in a single sheet over the entire width of the belt layer 3 in the illustrated example. In the present invention, the present invention is not limited to this, and a pair of the belt layers 3 may be disposed in a region covering both ends of the belt layer 3. These may be arranged in combination, and the number of each belt reinforcing layer is not limited to the above.

  Furthermore, a tread pattern (not shown) is appropriately formed on the surface of the tread portion 13, and an inner liner (not shown) is formed on the innermost layer. Furthermore, in the tire of the present invention, as the gas filled in the tire, normal or air having a changed oxygen partial pressure, or an inert gas such as nitrogen can be used.

Hereinafter, the present invention will be described in more detail with reference to examples.
Pneumatic tires for passenger cars of Examples and Comparative Examples were manufactured using a reinforcing member satisfying the conditions shown in the following table for the carcass ply at a tire size of 155 / 65R13. One reinforcing member was used. This reinforcing member was composed of a steel filament plated according to a conventional method and a rubber covering the steel filament, and the thickness was 1.0 mm. In each embodiment, the steel filament does not extend continuously between the widthwise ends of the reinforcing layer, i.e., at least one end of which is terminated in the reinforcing layer and is perpendicular to the reinforcing layer. The projection part which projected the steel filament on at least partially intersected. In addition, as the belt layer, reinforcing cords (material: steel cords) arranged at an angle of 22 ° with respect to the tire circumferential direction at a driving number of 30/50 mm were crossed in two layers.

Further, as Conventional Example 1-1, a commercially available pneumatic tire for passenger cars having a tire size of 155 / 65R13 (manufactured by BRIDGESTONE, SNEAKER2) was used.
Each of the obtained test tires was evaluated according to the following. The results are also shown in the table below.

<Hydraulic strength test>
After mounting each test tire on a rim with a rim size of 13 x 4.5 J, the internal pressure was continuously increased, and a water pressure test was conducted to evaluate how many times the tire would break under normal internal pressure, and the pressure at the time of failure was measured. did. If the pressure at the time of destruction is 1500 kPa or more, it can be said that there is no problem in practical use, and the higher the better.

<CBU test>
Each test tire was filled with an internal pressure of 100 kPa, loaded with a load of 3.6 kN, and run on a steel drum having a smooth road surface with a diameter of 1.707 m at a speed of 60 km / h. The tire outer surface was checked periodically every few hours, and if there was a crack in the rubber, it was stopped there. I drove for 10,000 km, and if there were no problems, I finished.

＊１）図６に示すような補強繊維の分散状態を意味する。

* 1) Means a dispersed state of reinforcing fibers as shown in FIG.

  From the results in the above table, in the test tires of the examples using the reinforcing members satisfying the conditions of the present invention, good results were obtained for both the hydraulic pressure test and the CBU test. It has been confirmed that such a reinforcing member is useful as a substitute for the conventional carcass ply. On the other hand, in each comparative example in which the reinforcing fibers are randomly arranged, there are few combinations of conditions that simultaneously satisfy the strength, durability, and moldability, and sufficient performance cannot be confirmed in the hydraulic pressure test in many cases. In particular, in Comparative Examples 1-5 and 1-8, in which the length of the reinforcing fiber is long and the basis weight density is high, the reinforcing member has poor expandability, that is, has high rigidity when unvulcanized and extends in the tire circumferential direction. As a result, the tire itself could not be molded.

  Reinforcing member satisfying the conditions shown in the following table in the tire size 155 / 65R13, in the region from the end of the belt layer to the vicinity of the winding end of the carcass ply outside the carcass ply of the sidewall Were arranged annularly in the tire circumferential direction, and pneumatic tires for passenger cars of Examples and Comparative Examples were produced. This reinforcing member was composed of a steel filament plated according to a conventional method and a rubber covering the steel filament, and the thickness was 1.0 mm. In each embodiment, the steel filament does not extend continuously between the widthwise ends of the reinforcing layer, i.e., at least one end of which is terminated in the reinforcing layer and is perpendicular to the reinforcing layer. The projection part which projected the steel filament on at least partially intersected.

  Carcass ply (cord material: PET, cord structure: 2 twists) is one piece, and the winding height is 88mm with reference to the rim diameter line, with the standard rim mounted and filled with the specified internal pressure It was. Further, as the belt layer, a reinforcing cord (material: steel cord (φ0.30 mm), structure: 1 × 3) arranged at an angle of 22 ° with respect to the tire circumferential direction at a driving number of 30/50 mm. Two layers were crossed.

Further, as Conventional Example 2-1, the carcass ply winding height was changed to 10 mm, and a tire without a reinforcing member was prepared. As Conventional Example 2-2, the carcass ply winding height was not changed and the tire was reinforced. A tire in which no members were arranged was produced. In Conventional Example 2-2, the rubber amount of the side portion is reduced as compared with Conventional Example 2-1, and the thickness of the side portion is thicker in Conventional Example 2-1, and in Conventional Example 2-2 and each Example. The comparative examples were equivalent.
Each of the obtained test tires was evaluated according to the following. The results are also shown in the table below.

<Weight index of reinforcing member>
The weight of the used reinforcing member was measured for each test tire. Here, in each example and comparative example, a sheet-like material of about 1100 mm × about 90 mm is used, and the weight of the reinforcing member indicates the weight. Moreover, about the conventional examples 2-1 and 2-2, the weight of the rubber | gum stuck on a side part was measured. The results were expressed as an index with the weight of Conventional Example 2-1 as 100. The smaller the value, the lighter and better.

<Tire weight index>
The weight of each test tire was measured and displayed as an index with the weight of Conventional Example 2-1 being 100. The smaller the value, the lighter and better.

<Steering stability>
A vehicle with each test tire mounted on four wheels was subjected to a straight line, lane change, and cornering to comprehensively evaluate steering stability. The result was obtained by calculating an average value of two test drivers and indicating an index value where the level of the control tire (conventional example 2-1) was 100. In the calculation, the figures after the decimal point are rounded off. At this time, the difference between the tire of the conventional example 2-1 and the tire of the conventional example 2-2 that does not have a reinforcing member was set to 10. The higher the number, the better the result.

<Hydraulic strength test>
It carried out like the above.

<Cut resistance>
A piece of 8cm metal square pillar is placed on the road surface, each test tire is mounted on the front wheel of the test vehicle, the internal pressure is adjusted to 100 kPa, and the average load is 300 kg, at an angle of about 30 degrees. A test was carried out on this square pillar. Starting from a speed of 30 km / h, the test speed is increased by 5 km / h, the speed at which the ply cord breaks in the side portion is set as the tire cutting speed, and an index with the conventional example 2-1 as 100 is displayed. did. The larger this value, the better the cut resistance and the better.

<Bead Durability Test (BF (Bead Fatigure) Drum Test)>
Each test tire was adjusted to an internal pressure of 3.0 kg / cm ² in a room of 25 ± 2 ° C. and then left for 24 hours. Thereafter, the air pressure was readjusted, a load twice as large as the JIS load was applied to the tire, and the tire was run on a drum having a diameter of about 3 m at a speed of 60 km / h for 20,000 km.

  From the results in the above table, it was confirmed that the test tires of the examples using the reinforcing members satisfying the conditions of the present invention were lightweight and had good performance for each evaluation item. . On the other hand, Comparative Example 2-1 in which the reinforcing fibers were randomly arranged was not sufficient in handling stability and cut resistance.

DESCRIPTION OF SYMBOLS 1 Bead core 2 Carcass 2a Winding end part 3 of carcass ply 3 Belt layer 4 Belt reinforcing layer 5 Reinforcing member 6 Bead filler 11 Bead part 12 Side wall part 13 Tread part 20 Protrusion 21 Reinforcing fiber 22 Rubber

Claims (10)

In a pneumatic tire having a pair of left and right bead portions and sidewall portions, and a tread portion continuous between both sidewall portions,
A reinforcing member comprising a reinforcing fiber plated or adhesive-treated and a rubber covering the reinforcing fiber is disposed annularly in the tire circumferential direction on at least a part of the sidewall portion. The fibers are oriented substantially in the tire radial direction in the sidewall portion, at least one end of the reinforcing fiber terminates in the reinforcing member, and the reinforcing fiber is projected in a direction perpendicular to the reinforcing member. A pneumatic tire characterized in that the projections intersect at least partially.   2. The pneumatic tire according to claim 1, wherein a carcass made of at least one carcass ply extending in a toroid shape extending between the pair of bead portions is used as a skeleton, and the carcass ply is made of the reinforcing member. The pneumatic tire according to claim ² , wherein the weight density of the reinforcing member is 100 g / m ² or more and 1500 g / m ² or less.   The pneumatic tire according to claim 2 or 3, wherein a length of the reinforcing fiber is in a range of 5 mm to 50 mm.   The pneumatic tire according to any one of claims 2 to 4, wherein a diameter of the reinforcing fiber is in a range of 0.07 mm to 0.34 mm.   The reinforcing member is provided in a skeleton of a carcass made of at least one carcass ply extending in a toroidal shape across the pair of bead parts, and at least a part of the side wall part outside the carcass ply. The pneumatic tire according to claim 1, wherein The pneumatic tire according to claim 6, wherein the weight density of the reinforcing member is 300 g / m ² or more and 1500 g / m ² or less.   The pneumatic tire according to claim 6 or 7, wherein a length of the reinforcing fiber is 15 mm or more.   The pneumatic tire according to any one of claims 6 to 8, wherein a diameter of the reinforcing fiber is in a range of 0.07 mm to 0.60 mm.   The pneumatic tire according to any one of claims 1 to 9, wherein the reinforcing fiber is an inorganic fiber.

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