Method for producing tire having sound damper on tire inner surface

Abstract

To provide a method for producing a tire capable of more appropriately correcting the weight unbalance of individual tires having sound dampers on the tire inner surfaces by using the sound damper.SOLUTION: The position of a light point K of the weight unbalance of a vulcanized tire 1 and a weight unbalance amount Bt are detected. A weight unbalance amount Bs of a sound damper 8 generated by an intermittent part 8i is determined based on the detected weight unbalance amount Bt of the tire 1 when the sound damper 8 is installed with at least one intermittent part 8i so as to extend in the tire circumferential direction with respect to a tire inner surface 7 of the tire 1. The sound damper 8 with a specification for generating the determined weight unbalance amount Bs is installed by joining to the tire inner surface 7 of the tire 1. At this time, the position of a light point P of the weight unbalance of the sound damper 8 is arranged in a range of ±30° in the tire circumferential direction centering on a position opposed to the position of the detected light point K of the tire 1.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a manufacturing method for a tire having a noise damper on its inner surface, and more specifically, to a manufacturing method for a tire that can more appropriately correct the weight imbalance of an individual tire having a noise damper on its inner surface by using the noise damper. [Background technology]

[0002] It is known to attach a noise-damping body to the inner surface of a tire in order to reduce cavity resonance noise in the tire (see, for example, Patent Document 1).When attaching a noise-damping body having a discontinuous portion to the inner surface of the tire, Patent Document 1 proposes that the influence on tire uniformity is suppressed by arranging the light point of the weight imbalance of the noise-damping body caused by the discontinuous portion in a range of ±60° centered on an opposing position separated by 180° from the light point of the weight imbalance of the tire body.

[0003] However, even for tires with the same specifications, the weight unbalance of each tire body is different, so when the same sound-damping body prepared for each tire specification is attached to the inner surface of the tire, the difference in the weight unbalance amount remains between the individual tires to which the sound-damping body is attached. That is, while there are some tires for which the weight unbalance amount is extremely small by attaching the sound-damping body, there are also some tires for which a certain level of weight unbalance remains. As a result, there is variation in uniformity between individual tires. Therefore, there is room for improvement in using the sound-damping body to more appropriately correct the weight unbalance of each tire equipped with a sound-damping body on the inner surface of the tire. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2006-335199 A Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a tire manufacturing method that can more appropriately correct the weight imbalance of individual tires having a noise damper on the inner surface of the tire by using the noise damper. [Means for solving the problem]

[0006] In order to achieve the above object, the manufacturing method of a tire having a sound damper on its inner surface of the tire of the present invention is characterized in that, in the manufacturing method of a tire having a sound damper on the inner surface of the tire located on the inner periphery of the tread portion, the position and amount of weight imbalance of a vulcanized tire are detected, and the amount of weight imbalance of the sound damper that would be caused by the intermittent portion when the sound damper is installed on the inner surface of the tire of the tire so as to extend in the tire circumferential direction with at least one intermittent portion is determined based on the detected amount of weight imbalance of the tire, and the sound damper of specifications that causes this determined amount of weight imbalance is installed on the inner surface of the tire of the tire, and at that time, the position of the light point of weight imbalance of the sound damper is positioned within a range of ±30° in the tire circumferential direction, centered on a position facing the detected position of the light point of weight imbalance of the tire. Effect of the Invention

[0007] According to the present invention, by arranging the light point of the noise damper in a range of ±30° in the tire circumferential direction centered on a position facing the light point of the weight imbalance of the vulcanized tire, the weight imbalance of the tire can be corrected by utilizing the weight imbalance of the noise damper installed on the inner surface of the tire. Moreover, since the weight imbalance amount of the noise damper is determined based on the detected weight imbalance amount of the tire, the weight imbalance of each tire having the noise damper on the inner surface of the tire can be corrected more appropriately by using the noise damper. As a result, the variation in uniformity between individual tires is suppressed. [Brief description of the drawings]

[0008] [Figure 1]FIG. 2 is an explanatory diagram illustrating the inside of a tire manufactured according to the present invention as viewed from the side. [Diagram 2] FIG. 2 is an explanatory diagram illustrating the tire of FIG. 1 in a cross-sectional view. [Diagram 3] FIG. 4 is an explanatory diagram illustrating a noise damper used in the present invention as viewed from the side. [Figure 4] FIG. 11 is an explanatory diagram illustrating another noise damper that is used as seen from the side. [Diagram 5] 4A to 4C are explanatory diagrams illustrating, from a side view, a process of attaching a noise damper to an inner surface of a tire. [Figure 6] FIG. 10 is an explanatory diagram illustrating the inside of another tire manufactured according to the present invention as seen from the side. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, a method for manufacturing a tire having a noise damper on the inner surface of the tire according to the present invention will be described based on an embodiment shown in the drawings.

[0010] The tire 1 illustrated in Fig. 1 and Fig. 2 is manufactured by the tire manufacturing method of the present invention. The tire 1 is provided with a noise-damping body 8 on the tire inner surface 7. The tire inner surface 7 is a surface that exists on the inner circumferential side of the tread portion 6 of the tire 1. CL and Z in the drawings respectively indicate the widthwise center and tire axis of the tire 1. Also, arrows W, R, and C in the drawings respectively indicate the widthwise direction, radial direction, and circumferential direction of the tire 1.

[0011] The tire 1 on which the noise damper 8 is installed is a variety of pneumatic tires. The structure of this tire 1 is such that an inner liner 3 is disposed on the innermost circumference, and a carcass layer 4 is laminated on the outer circumferential side thereof. The carcass layer 4 is mounted between a pair of left and right bead portions 2. Both left and right ends of the carcass layer 4 are folded back from the inner side of the tire to the outer side around the bead cores of the respective bead portions 2. Two belt layers 5 are laminated on the outer circumferential side of the center portion of the carcass layer 4 in the tire width direction, and a tread portion 6 is laminated on the outer circumferential side thereof. The number of layers of the belt layer 5 is appropriately set. Side portions are laminated on the outer sides of both sides of the carcass layer 4 in the tire width direction. Shoulder portions are laminated on the outer sides of the carcass layer 4 between the tread portion 6 and each side portion. The tire 1 is not limited to this structure, and may be provided with, for example, a belt cover layer that is laminated on the outer circumferential side of the belt layer 5 and covers both ends of the belt layer 5, in addition to the above-mentioned members.

[0012] The noise damper 8 is sponge-like (porous) and has a sound absorbing function. As the noise damper 8, various known specifications such as various vulcanized rubbers and various resin foams can be adopted. The specific gravity of the noise damper 8 is, for example, 0.005 to 0.08, and more preferably 0.01 to 0.04.

[0013] The noise damper 8 has at least one intermittent portion 8i and is joined to the tire inner surface 7, extending in the tire circumferential direction. The intermittent portion 8i is between the leading end 8t and the trailing end 8e in the longitudinal direction of the noise damper 8. In this embodiment, there is one intermittent portion 8i, but there may be two (multiple) intermittent portions 8i. The noise damper 8 and the tire inner surface 7 are joined by, for example, double-sided adhesive tape or adhesive. The double-sided adhesive tape or adhesive suitable for joining the noise damper 8 and the tire inner surface 7 is selected from various known specifications.

[0014] The size of the noise damper 8 varies depending on the size of the tire 1, etc., but the length (length in the tire circumferential direction) of the noise damper 8 is, for example, 60% to 95% of the circumferential length of the tire inner surface 7, the width of the noise damper 8 is, for example, 10% to 80% of the size width of the tire 1, and the thickness of the noise damper 8 is, for example, 10 mm to 50 mm.

[0015] In this embodiment, the noise damper 8 is strip-shaped with a constant width and thickness, but is not limited to this shape and various shapes can be adopted. For example, for the strip-shaped noise damper 8 of this embodiment, a shape in which the width of at least one of both ends in the tire circumferential direction (the periphery of the leading end 8t and the trailing end 8e) is reduced, a shape in which the thickness of at least one of both ends in the tire circumferential direction is reduced, a shape in which the thickness varies in the tire width direction, etc. can be adopted.

[0016] Next, an example of a procedure for manufacturing the tire 1 having the noise damper 8 on the tire inner surface 7 will be described.

[0017] First, a green tire (unvulcanized tire) is vulcanized by a known method to manufacture a tire 1 that does not include a noise damper 8. Next, after the vulcanization process of this tire 1, and before the noise damper 8 is installed on the tire inner surface 7, the position of a light point K of the weight imbalance in the tire circumferential direction and the weight imbalance amount Bt of the tire 1 are detected by a known inspection device. This light point K is the position on the tire 1 that is the lightest in the tire circumferential direction.

[0018] Next, when a noise damper 8 is installed on the tire inner surface 7 of this tire 1, extending in the tire circumferential direction with at least one intermittent portion 8i, the tire circumferential weight unbalance amount Bs of the noise damper 8 caused by the intermittent portion 8i is determined based on the detected weight unbalance amount Bt of the tire T. For example, the larger the weight unbalance amount Bt of the tire T, the larger the weight unbalance amount Bs of the noise damper 8 is made. At this time, the weight unbalance amount Bs is changed steplessly or stepwise according to the weight unbalance amount Bt. As a result, the weight unbalance amount Bs is determined so that the variation in the weight unbalance amount (Bs-Bt) of the tire 1 when the noise damper 8 is installed on the tire inner surface 7 between tires 1 of the same specifications is minimized.

[0019] Next, the noise damper 8 having the specifications to generate the determined weight unbalance amount Bt is attached to the tire inner surface 7 of the tire 1 and installed. When installing the noise damper 8, the position of the light point P of the weight unbalance of the noise damper 8 is arranged in a range of ±30° in the tire circumferential direction from the position facing the position of the detected light point K of the tire 1 as the center. In other words, the angle a in FIG. 1 is set to 0° or more and 30° or less. This light point P is the lightest position in the tire circumferential direction of the noise damper 8 installed to extend in the tire circumferential direction along the tire inner surface 7. When the noise damper 8 is a strip-shaped body with a constant width and thickness as in this embodiment, the center position in the tire circumferential direction of the intermittent portion 8i corresponds to the light point P.

[0020] To make the sound damping body 8 have specifications that produce the determined weight unbalance amount Bs, for example, at least one of the following three types is changed: the length of the intermittent portion 8i in the tire circumferential direction, the width of the end of the sound damping body 8 in the tire circumferential direction, or the thickness of the end of the sound damping body 8 in the tire circumferential direction. When there is one intermittent portion 8i, increasing the length of the intermittent portion 8i in the tire circumferential direction increases the weight unbalance amount Bs, and decreasing the length of the intermittent portion 8i in the tire circumferential direction decreases the weight unbalance amount Bs. Reducing the width of the end of the sound damping body 8 in the tire circumferential direction increases the weight unbalance amount Bs. Reducing the thickness of the end of the sound damping body 8 in the tire circumferential direction increases the weight unbalance amount Bs.

[0021] A method for making the noise damper 8 have specifications that produce the determined weight unbalance amount Bs will be specifically described. As illustrated in FIG. 3, the tire circumferential length of the intermittent portion 8i is changed by adjusting the length when the long object 8G of the noise damper 8 is cut to form the noise damper 8 per tire for each tire. The longer the length when the long object 8G is cut to form the noise damper 8 per tire, the smaller the tire circumferential length of the intermittent portion 8i. In this way, the weight unbalance amount Bs is changed steplessly according to the weight unbalance amount Bt, and the noise damper 8 having the specifications that produce the determined weight unbalance amount Bs can be obtained. The method of adjusting the length when the long object 8G of the noise damper 8 is cut to form the noise damper 8 per tire for each tire 1 is advantageous for obtaining a noise damper 8 having optimal specifications for each individual tire 1.

[0022] As illustrated in FIG. 4, a plurality of specifications of noise dampers 8 (8A, 8B, 8C) with different lengths are prepared, and one specification of the noise damper 8 is selected from the prepared specifications, thereby changing the tire circumferential length of the intermittent portion 8i. For example, the detected weight unbalance amount Bt is divided into a plurality of categories (for example, 2 to 5) according to the magnitude of the weight unbalance amount Bt. In this embodiment, the detected weight unbalance amount Bt is divided into three categories. Then, noise dampers 8 (8A, 8B, 8C) with specifications corresponding to the respective categories are prepared. In detail, for the category with the largest weight unbalance amount Bt, the noise damper 8A with the shortest length (tire circumferential length) is selected. For the category with the second largest weight unbalance amount Bt, the noise damper 8B with the second shortest length (tire circumferential length) is selected. For the category with the smallest weight unbalance amount Bt, the noise damper 8C with the longest length (tire circumferential length) is selected. In this way, the weight unbalance amount Bs can be changed stepwise according to the weight unbalance amount Bt to obtain a noise damper 8 with a specification that produces the determined weight unbalance amount Bs. The method of selecting one specification from a plurality of specifications of noise dampers 8 (8A, 8B, 8C) with different lengths is advantageous in avoiding a cumbersome process of installing the noise damper 8 on the inner surface 7 of the tire, since the noise dampers 8 (8A, 8B, 8C) with each specification can be prepared in advance.

[0023] Alternatively, the degree of expansion and contraction of the noise damper 8 can be adjusted by adjusting the tension applied to the noise damper 8 when the noise damper 8 is installed on the tire inner surface 7 for each tire 1. This allows the tire circumferential length of the intermittent portions 8i to be changed, and the noise damper 8 can be designed to generate the determined weight imbalance amount Bs.

[0024] More specifically, when the noise damper 8 is installed on the inner surface 7 of the tire, a cylindrical casing 10 as shown in FIG. 5 is used. This casing 10 is missing a part of the cylindrical wall in the circumferential direction, and further has a pressing part 11 and a winding part 12 on the outer circumferential surface of the wall. In this embodiment, a leaf spring is used as the pressing part 11, but a pressing roller or the like can also be used. Inside the cylindrical casing 10, the noise damper 8 is held in a spirally wound state. One side of the noise damper 8 is provided with an adhesive layer 9a such as a double-sided adhesive tape, and the adhesive layer 9a is covered with a release paper 9b.

[0025] The casing 10 holding the sound-damping body 8 is placed inside the tire 1, and the release paper 9b is taken up by the take-up unit 12 from the sound-damping body 8 pulled out from inside the casing 10, thereby peeling off the release paper 9b and exposing the adhesive layer 9a. Then, while rotating the tire 1 in one circumferential direction, the part of the sound-damping body 8 where the adhesive layer 9a is exposed is pressed by the pressing unit 11 to press the adhesive layer 9a against the tire inner surface 7. As a result, the sound-damping body 8 is pulled out from the casing 10 and is bonded to the tire inner surface 7 via the adhesive layer 9a and installed. The tension applied to the sound-damping body 8 is changed by changing the pressing force by the pressing unit 11 and the winding speed of the release paper 9b by the wind-up unit 12. Therefore, the tension applied to the sound-damping body 8 when it is installed on the tire inner surface 7 is adjusted to adjust the degree of expansion and contraction of the sound-damping body 8. The greater the tension applied to the noise damper 8, the more the noise damper 8 stretches, and therefore the shorter the length of the intermittent portions 8i in the tire circumferential direction, and the smaller the tension applied to the noise damper 8, the longer the length of the intermittent portions 8i in the tire circumferential direction. In this way, the weight unbalance amount Bs can be changed steplessly or stepwise according to the weight unbalance amount Bt to obtain a noise damper 8 with specifications that produce a determined weight unbalance amount Bs. With the method of adjusting the tension applied to the noise damper 8, it is relatively easy to obtain a noise damper 8 with specifications suitable for each individual tire 1, but it is not possible to change the degree of stretch of the noise damper 8 significantly.

[0026] As described above, by arranging the light point P of the sound damper 8 in the range of ±30° in the tire circumferential direction centered on the position facing the position of the light point K of the weight imbalance of the vulcanized tire 1, the weight imbalance of the tire 1 can be corrected by utilizing the weight imbalance of the sound damper 8 installed on the tire inner surface 7. Accordingly, the sound damper 8 installed on the tire inner surface 7 can reduce the cavity resonance sound of the tire 1 and produce a tire 1 with excellent uniformity. In order to improve the uniformity of the tire 1, it is more preferable to arrange the position of the light point P of the sound damper 8 in the range of ±10° in the tire circumferential direction centered on the position facing the position of the light point K of the tire 1, and even more preferable to arrange it in the range of ±5°.

[0027] Furthermore, according to the manufacturing method of the tire 1, the weight unbalance amount Bs of the sound damping body 8 is determined based on the detected weight unbalance amount Bt of the tire 1. Since the tire 1 illustrated in FIG. 1 has a relatively small weight unbalance amount Bt, the weight unbalance amount Bs of the sound damping body 8 is determined to be a relatively small value, and accordingly, the tire circumferential length of the intermittent portion 8i of the sound damping body 8 is relatively small. On the other hand, since the tire 1 illustrated in FIG. 6 has a relatively large weight unbalance amount Bt, the weight unbalance amount Bs of the sound damping body 8 is determined to be a relatively large value, and accordingly, the tire circumferential length of the intermittent portion 8i of the sound damping body 8 is relatively large. Therefore, the weight unbalance of each tire 1 having the sound damping body 8 on the tire inner surface 7 can be more appropriately corrected by using the sound damping body 8. Accordingly, the variation in uniformity between each tire T having the sound damping body 8 is suppressed. [Explanation of symbols]

[0028] 1 Tire 2 Bead section 3 Inner Liner 4 Carcass layer 5 Belt Layer 6 Tread 7 Tire inner surface 8(8A, 8B, 8C) Sound damping body 8G Long sound-absorbing body 8t tip 8e rear end 8i Intermittent part 9a Adhesive layer 9b Release paper 10 Casing 11 Pressing section 12 Winding section

Claims

1. A method for manufacturing a tire having a noise-damping body on an inner surface of the tire located on the inner circumferential side of the tread portion, A method for manufacturing a tire with a sound damper on an inner surface of the tire, comprising: detecting the position and amount of weight imbalance of a light point of weight imbalance of a vulcanized tire; determining the amount of weight imbalance of the sound damper that would be caused by the intermittent portion when the sound damper is installed on the inner surface of the tire of the tire so as to extend in the tire circumferential direction with at least one intermittent portion, based on the detected amount of weight imbalance of the tire; installing the sound damper of specifications that cause this determined amount of weight imbalance on the inner surface of the tire; and positioning the position of the light point of weight imbalance of the sound damper within a range of ±30° in the tire circumferential direction, centered on a position facing the detected position of the light point of weight imbalance of the tire.

2. 2. A method for manufacturing a tire having a noise damper on its inner surface as described in claim 1, wherein the noise damper is designed to generate the determined weight imbalance amount by changing at least one of the following three types: the tire circumferential length of the intermittent portion of the noise damper, the tire circumferential end width of the noise damper, or the tire circumferential end thickness of the noise damper.

3. 3. A method for manufacturing a tire having a noise damper on its inner surface as described in claim 2, wherein the circumferential length of the intermittent portion is changed for each tire by adjusting the length when cutting the long piece of noise damper to form the noise damper per tire, in order to conform the noise damper to a specification that generates the determined amount of weight imbalance.

4. 3. A method for manufacturing a tire having a noise damper on the inner surface of the tire as described in claim 2, wherein a plurality of specifications of the noise damper having different lengths are prepared in order to make the noise damper have a specification that generates the determined amount of weight imbalance, and the circumferential length of the intermittent portion is changed by selecting one specification of the noise damper from the plurality of specifications prepared.

5. 3. A method for manufacturing a tire having a noise damper on an inner surface of the tire as described in claim 2, wherein, in order to conform the noise damper to a specification that generates the determined amount of weight imbalance, the tension applied to the noise damper when installing the noise damper on the inner surface of the tire is adjusted to adjust the degree of expansion and contraction of the noise damper for each tire, thereby changing the circumferential length of the intermittent portion.

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