JP2006264406A - Noise reduction device, its manufacturing method and pneumatic tire furnished therewith - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a noise reduction device free to improve adhesiveness of a sound absorbing material made of a porous material and to shorten processing hours, its manufacturing method and a pneumatic tire furnished with the noise reduction device. <P>SOLUTION: This noise reduction device 4 is furnished with the noise absorbing material 5 made of porous material and a band member 6 to install the noise absorbing material 5 on a tire inner surface, wherein a coating part 5a constituted by applying thermoplastic resin against an inner cell on the noise absorbing material 5 is formed while the band member 6 is constituted of the thermoplastic resin, and the coating part 5a is thermally-bonded to the band member 6. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an apparatus for reducing cavity resonance sound generated in a pneumatic tire, and more specifically, improves adhesion of a sound absorbing material made of a porous material, and further shortens a processing time. The present invention relates to a noise reduction device, a manufacturing method thereof, and a pneumatic tire including the noise reduction device.

  In a pneumatic tire, one of the causes for generating noise is cavity resonance sound caused by vibration of air filled in the tire. This cavity resonance sound is generated when the tread portion vibrates due to road surface irregularities when the tire rolls, and the vibration of the tread portion vibrates the air inside the tire.

  As a technique for reducing noise due to such a cavity resonance phenomenon, it has been proposed to arrange a sound absorbing material in a cavity formed between a tire and a rim of a wheel. (For example, refer to Patent Document 1). However, when the sound absorbing material is affixed to the rim outer peripheral surface of the wheel, the sound absorbing material impedes the rim assembling work, and when the sound absorbing material is affixed to the tire inner surface, there is a disadvantage that the affixing work is troublesome.

On the other hand, it has been proposed that an object for obtaining a sound absorbing effect is attached to an annular band member, and the object is attached to the inner surface of the tire in the tread portion based on the elastic force of the band member (see, for example, Patent Document 2). . By adopting such a method, the sound absorbing material can be easily attached to the tire inner surface. However, for example, when a sound-absorbing material made of a porous material such as polyurethane foam is fixed to the band member using an adhesive or an adhesive tape, the porous material reacts with components contained in the adhesive or the adhesive tape. May decompose and the adhesiveness of the sound-absorbing material may decrease. Therefore, the method of fixing the sound absorbing material with the band member has an advantage that the sound absorbing material can be easily attached to the tire inner surface, but is insufficient in terms of durability. Further, when the sound absorbing material is bonded to the band member with an adhesive, there is a disadvantage that it takes a long time to harden the adhesive.
Japanese Patent Application Laid-Open No. 64-78902 JP 2003-226104 A

  An object of the present invention is to improve the adhesion of a sound absorbing material made of a porous material and further reduce the processing time, a method for manufacturing the same, and a pneumatic apparatus equipped with the noise reducing device. To provide tires.

  The noise reduction device of the present invention for solving the above object is a noise reduction device comprising a sound absorbing material made of a porous material and a band member for mounting the sound absorbing material on the inner surface of the tire. While comprising a thermoplastic resin, the sound absorbing material is formed with a coating portion formed by adhering a thermoplastic resin to an internal cell, and the coating portion is heat-sealed to the band member. It is what.

  In order to solve the above-described object, a noise reduction device manufacturing method of the present invention manufactures a noise reduction device including a sound absorbing material made of a porous material and a band member for mounting the sound absorbing material on the tire inner surface. In the method, the band member is made of a thermoplastic resin, the sound absorbing material is partially impregnated with a solution in which the thermoplastic resin is dispersed in a solvent, and the sound absorbing material has the thermoplastic resin with respect to the internal cell. A coating portion formed by applying a resin is formed, and the coating portion is heat-sealed to the band member.

  In the present invention, the band member is made of a thermoplastic resin, while a coating portion made of a thermoplastic resin is formed on the sound absorbing material, and the coating portion is thermally fused to the band member. Therefore, even if the sound absorbing material is made of a thermosetting resin such as foamed polyurethane, the coating portion can be firmly fixed to the band member. Fixing by heat fusion is different from fixing by adhesive or adhesive tape, and does not cause a decrease in adhesive force due to decomposition reaction, and the sound absorbing material made of porous material has a good adhesive state over a long period of time. Can be maintained. Moreover, since the process by heat fusion is completed in a short time compared with the process by an adhesive agent, the processing time of a noise reduction apparatus can be shortened.

  The constituent material of the band member and the coating material of the sound absorbing material are preferably the same kind of thermoplastic resin, for example, polypropylene. On the other hand, the porous material of the sound absorbing material is preferably foamed polyurethane. That is, polyurethane foam is suitable as a constituent material of the sound absorbing material because it exhibits good sound absorbing characteristics.

  In the noise reduction device of the present invention, the coating portion is formed not to be exposed on the surface opposite to the band member of the sound absorbing material but to be exposed only on the surface of the sound absorbing material on the band member side, The volume is preferably 10% or less of the total volume of the sound absorbing material. Thereby, the fall of the sound absorption effect can be suppressed to the minimum. The width Ws of the coating portion is preferably in a relationship of 0.5 Wb ≦ Ws ≦ 1.5 Wb with respect to the width Wb of the band member. Thereby, the joining operation | work of a band member and a sound-absorbing material becomes easy. Furthermore, it is preferable that the portions where the coating portion is heat-sealed are arranged at intervals in the tire circumferential direction, and the interval H is in a relationship of 0.2W ≦ H ≦ 4W with respect to the width W of the sound absorbing material. As a result, good durability can be ensured with minimal processing.

  In the manufacturing method of the noise reduction device of the present invention, it is preferable to use an ultrasonic welder for heat fusion of the coating portion. When such an ultrasonic welder is used, the coating portion and the band member can be locally heated, so that the balance between workability and durability is excellent. In particular, the ultrasonic welding machine is effective when the constituent material of the band member and the coating material of the sound absorbing material are polypropylene.

  According to the present invention, there is provided a pneumatic tire provided with the noise reduction device in the cavity. In such a pneumatic tire, an excellent noise reduction effect can be obtained based on the sound absorbing material of the noise reduction device, and the noise reduction effect can be maintained for a long period of time.

  Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 shows a pneumatic tire according to an embodiment of the present invention, and FIG. 2 shows a noise reduction device according to an embodiment of the present invention. In FIG. 1, the pneumatic tire includes a tread portion 1, a pair of left and right bead portions 2, and a sidewall portion 3 that connects the tread portion 1 and the bead portion 2 to each other. A ring-shaped noise reduction device 4 shown in FIG. 2 is mounted on the inner surface of the tread portion 1.

  The noise reduction device 4 includes a sound absorbing material 5 made of a porous material, and a band member 6 for mounting the sound absorbing material 5 on the tire inner surface. The sound absorbing material 5 has a large number of internal cells and has predetermined sound absorbing characteristics based on the porous structure. As the porous material of the sound absorbing material 5, foamed polyurethane may be used. On the other hand, the band member 6 is formed in an annular shape so as to continuously extend in the tire circumferential direction. The band member 6 holds the sound absorbing material 5 on the tire inner surface based on the elastic restoring force. The noise reduction device 4 configured as described above is detachable from a normal pneumatic tire, and the attachment / detachment work is easy.

  In the noise reduction device 4, heat fusion is employed as a fixing means for the sound absorbing material 5 and the band member 6. In order to enable heat fusion, the band member 6 is made of a thermoplastic resin. On the other hand, the sound absorbing material 5 is formed with a coating portion 5 a formed by adhering a thermoplastic resin to the internal cell, and the coating portion 5 a is heat-sealed to the band member 6. Moreover, it is good to use the same kind of thermoplastic resin, for example, a polypropylene, for the constituent material of the band member 6 and the coating material of the sound absorbing material 5.

  3A to 3C show an example of a heat fusion method between the sound absorbing material and the band member. First, as shown in FIG. 3A, the sound absorbing material 5 is partially impregnated with a solution (for example, polypropylene emulsion) in which a thermoplastic resin is dispersed in a solvent, and the sound absorbing material 5 is applied to the inner cell. Thus, a coating portion 5a formed by depositing a thermoplastic resin is formed. Here, although it is desirable to dry the coating part 5a, it may be in a wet state. Next, as shown in FIG. 3B, after the sound absorbing material 5 is overlaid on the band member 6 and the coating portion 5a is aligned with the position of the band member 6, the vibration horn 11 of the ultrasonic welder is sound-absorbed. It presses on the position corresponding to the coating part 5a of the material 5, and the part is heated locally. Thereby, as shown in FIG.3 (c), the coating part 5a and the band member 6 are heat-seal | fused.

  As shown in the figure, when the coating portion 5a is formed not to be exposed on the surface of the sound absorbing material 5 opposite to the band member 6, but to be exposed only on the surface of the sound absorbing material 5 on the band member 6 side, the sound absorbing effect is obtained. Can be minimized. For the same reason, the total volume of the coating portion 5a is 10% or less, more preferably 5% or less of the total volume of the sound absorbing material 5. That is, if the total volume of the coating portion 5a becomes excessive, the sound absorbing effect is reduced.

  FIGS. 4A and 4B show another example of a heat fusion method between the sound absorbing material and the band member. In this case, as shown in FIG. 4 (a), a solution in which a thermoplastic resin is dispersed in a solvent is partially impregnated into the sound absorbing material 5 from the nozzle 12 to form a coating portion 5a and at the same time ultrasonic welding. The vibration horn 11 of the machine is pressed to a position corresponding to the coating portion 5a of the sound absorbing material 5, and the portion is locally heated. Thereby, as shown in FIG.4 (b), the coating part 5a and the band member 6 are heat-seal | fused.

  In the noise reduction device 4, the band member 6 is made of a thermoplastic resin, while the sound absorbing material 5 is formed with a coating portion 5 a made of a thermoplastic resin, and the coating portion 5 a is thermally fused to the band member 6. Therefore, even if the sound absorbing material 5 is made of a thermosetting resin such as foamed polyurethane, the coating portion 5 a can be firmly fixed to the band member 6. Fixing by heat fusion, unlike fixing by an adhesive or adhesive tape, does not cause a decrease in adhesive force due to a decomposition reaction, and can improve the adhesiveness of the sound absorbing material 5 made of a porous material. Moreover, since the process by heat fusion is completed in a short time compared with the process by an adhesive agent, the processing time of the noise reduction apparatus 4 can be shortened.

  And in the pneumatic tire which provided the said noise reduction apparatus 4 in the cavity part, the noise reduction effect outstanding with the sound-absorbing material 5 can be acquired, and also the noise reduction effect can be maintained over a long period of time.

  FIG. 5 shows a state in which the noise reduction device is developed on a plane. As shown in FIG. 5, the width Ws of the coating portion 5 a is preferably in a relationship of 0.5 Wb ≦ Ws ≦ 1.5 Wb with respect to the width Wb of the band member 6. If 0.5 Wb> Ws, the joining operation of the band member 6 and the sound absorbing material 5 becomes difficult, and conversely if Ws> 1.5 Wb, the sound absorbing effect is reduced. Further, the portions where the coating portion 5a is heat-sealed are arranged at intervals (pitch) in the tire circumferential direction, and the interval H is in a relationship of 0.2W ≦ H ≦ 4W with respect to the width W of the sound absorbing material 5. good. If 0.2W> H, the workability at the time of heat-sealing deteriorates. Conversely, if H> 4W, the joining state of the sound absorbing material 5 to the band member 6 becomes unstable. In addition, the site | part which heat-seal | coats the coating part 5a does not necessarily need to be equal intervals.

  6 to 9 show states in which variations of the noise reduction device are developed on a plane, respectively. In FIG. 6, the plan view shape of the coating portion 5a is a quadrangle. That is, the planar view shape of the coating portion 5a is not particularly limited, and can be an arbitrary shape such as a circle or a rectangle. Moreover, as shown in FIG. 7, it is also possible to provide the coating part 5a continuously in the tire circumferential direction. Further, as shown in FIGS. 8 and 9, the sound absorbing material 5 may be constituted by a plurality of divided pieces, and these divided pieces may be arranged along the longitudinal direction of the band member 6. It is preferable that each divided piece of the sound absorbing material 5 is heat-sealed to the band member 6 at at least two places.

  The noise reduction apparatus of the prior art example and an Example was each manufactured. The conventional noise reduction device fixes a sound absorbing material made of a band-like urethane foam (width 150 mm × thickness 20 mm) to a polypropylene band member (width 20 mm × thickness 2 mm × tire inner circumferential length) using an adhesive. The band member is formed into an annular shape. The noise reduction device of the example is formed by impregnating a sound absorbing material made of a strip-like urethane foam (width 150 mm × thickness 20 mm) with a polypropylene emulsion at intervals of about 200 mm along the length direction to form a coating portion and ultrasonic welding. The coating part is heat-sealed to a polypropylene band member (width 20 mm × thickness 2 mm × tire inner circumferential length) using a machine. The total volume of the coating portion was 5% of the total volume of the sound absorbing material.

The noise reduction devices of these conventional examples and examples are mounted on pneumatic tires of tire size 215 / 55R16, respectively, and run on a drum testing machine under conditions of an internal pressure of 150 kPa and a speed of 80 km / h, and peeling occurs in the sound absorbing material. The distance traveled was measured. The results are shown in Table 1. The evaluation results are shown as an index with the conventional example being 100. The larger the index value, the better the durability.

  As can be seen from Table 1, the durability of the noise reduction device of the example was significantly improved compared to the conventional example.

1 is a perspective sectional view showing a pneumatic tire according to an embodiment of the present invention. It is a perspective view which shows the noise reduction apparatus which consists of embodiment of this invention. An example of the heat sealing | fusion method of a sound-absorbing material and a band member is shown, (a)-(c) is sectional drawing of each process. The other example of the heat sealing | fusion method of a sound-absorbing material and a band member is shown, (a)-(b) is sectional drawing of each process. It is a top view which shows the state which expand | deployed the noise reduction apparatus on the plane. It is a top view which shows the state which expand | deployed the modification of the noise reduction apparatus on the plane. It is a top view which shows the state which expand | deployed the modification of the noise reduction apparatus on the plane. It is a top view which shows the state which expand | deployed the modification of the noise reduction apparatus on the plane. It is a top view which shows the state which expand | deployed the modification of the noise reduction apparatus on the plane.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tread part 2 Bead part 3 Side wall part 4 Noise reduction apparatus 5 Sound absorbing material 5a Coating part 6 Band member 11 Excitation horn of ultrasonic welding machine

Claims (14)

In a noise reduction device comprising a sound absorbing material made of a porous material and a band member for mounting the sound absorbing material on the inner surface of the tire, the band member is made of a thermoplastic resin, and the sound absorbing material has an internal cell. A noise reduction device in which a coating portion is formed by adhering a thermoplastic resin to the band member, and the coating portion is thermally fused to the band member. The noise reduction device according to claim 1, wherein the constituent material of the band member and the coating material of the sound absorbing material are the same kind of thermoplastic resin. The noise reduction device according to claim 1, wherein both the constituent material of the band member and the coating material of the sound absorbing material are polypropylene. The noise reduction device according to any one of claims 1 to 3, wherein the porous material of the sound absorbing material is polyurethane foam. The said coating part was formed so that it might expose only to the surface by the side of the band member of the said sound-absorbing material, without exposing it to the surface on the opposite side to the band member of the said sound-absorbing material. Noise reduction device. The noise reduction device according to any one of claims 1 to 5, wherein a total volume of the coating portion is 10% or less of a total volume of the sound absorbing material. The noise reduction device according to any one of claims 1 to 6, wherein the width Ws of the coating portion is in a relationship of 0.5 Wb ≤ Ws ≤ 1.5 Wb with respect to the width Wb of the band member. The site | part which heat-seal | fuses the said coating part is arrange | positioned at intervals in the tire circumferential direction, The space | interval H was made into the relationship of 0.2W <= H <= 4W with respect to the width W of the said sound-absorbing material. The noise reduction apparatus in any one of. In a method of manufacturing a noise reduction device including a sound absorbing material made of a porous material and a band member for mounting the sound absorbing material on the inner surface of the tire, the band member is made of a thermoplastic resin and heated in a solvent. A solution in which a plastic resin is dispersed is partially impregnated into the sound-absorbing material, and a coating portion is formed on the sound-absorbing material by adhering the thermoplastic resin to an internal cell. A method of manufacturing a noise reduction device that is thermally fused to a band member. The manufacturing method of the noise reduction apparatus of Claim 9 which used the ultrasonic welding machine for the heat fusion of the said coating part. The manufacturing method of the noise reduction device according to claim 9 or 10, wherein the constituent material of the band member and the coating material of the sound absorbing material are the same kind of thermoplastic resin. The manufacturing method of the noise reduction device according to claim 9 or 10, wherein both the constituent material of the band member and the coating material of the sound absorbing material are polypropylene. The method for manufacturing a noise reduction device according to claim 8, wherein the porous material of the sound absorbing material is polyurethane foam. A pneumatic tire provided with the noise reduction device according to claim 1 in the cavity.

Images