JP5446201B2 - Low noise pneumatic tire - Google Patents

Description

  The present invention relates to a low-noise pneumatic tire, and more particularly to a low-noise pneumatic tire that improves the durability of a sound-absorbing material made of a porous resin material when traveling in a cold region.

  One of the causes of noise generated by a pneumatic tire during travel is cavity resonance due to vibration of air filled in the tire. This cavity resonance sound is generated when the tread portion vibrates due to the unevenness of the road surface when the tire rolls, and when the vibration of the tread portion vibrates the air inside the tire.

  As a method of reducing noise due to such cavity resonance phenomenon, many proposals have been made to arrange a sound absorbing material made of a porous resin material such as urethane foam in a cavity formed between a tire and a wheel rim. (Patent Document 1, etc.).

However, the sound-absorbing material formed from this resin material generally has a characteristic that it becomes brittle at low temperatures. In particular, urethane that is frequently used as a sound absorbing material has a large tendency to become brittle. For this reason, when the pneumatic tire travels in a cold area such as several tens of degrees below freezing for a long time, there is a problem in that the sound absorbing material may become brittle due to the low temperature transmitted through the tread portion and may crack.
WO2005 / 012005 pamphlet

The object of the present invention is to solve the above-mentioned problem of a sound absorbing material made of a porous material that is a urethane foam, and to use the sound absorbing material made of a porous material that is a urethane foam even when used in a cold region such as several tens of degrees below freezing. It is an object of the present invention to provide a low-noise pneumatic tire excellent in durability for suppressing cracking due to embrittlement.

  The low-noise pneumatic tire of the present invention that achieves the above-described object has the following configuration (1).

(1) In a low-noise pneumatic tire in which a band-shaped sound absorbing material made of a porous resin material that is urethane foam is attached by an elastic fixing band that is in pressure contact with the tire inner peripheral surface, on the tire inner peripheral surface side of the sound absorbing material, together comprising a thermoplastic elastomer composition the elastomer dispersed in a thermoplastic resin, the sound absorbing material protective sheet of thickness 0.1~1mm covering the entire surface of the tire inner peripheral surface of the belt-shaped sound absorbing material is arranged, and An inner liner layer made of a thermoplastic elastomer composition in which an elastomer is dispersed in a thermoplastic resin is disposed on the inner circumferential surface of the tire, and the sound absorbing material protective sheet and the inner liner layer have substantially the same composition. It is composed of the composition, and especially in that said elastic fixing band and the sound absorbing material are integral with pivotal points by welding process Low-noise pneumatic tire to be.

According to the present invention, an elastomer is contained in a thermoplastic resin on a tire inner peripheral surface side with respect to a band-shaped sound absorbing material made of a porous resin material that is urethane foam pressed against an inner peripheral surface of a tire by an elastic fixing band. Since the protective sheet made of the dispersed thermoplastic elastomer composition is disposed so as to cover the entire surface on the inner peripheral surface side of the tire, when this protective sheet travels in a cold region, the low temperature from the tread is cut off, and the sound absorbing material Embrittlement can be prevented. That is, since the elastomer in the thermoplastic elastomer composition has a significantly low embrittlement temperature compared to the resin component, it does not become brittle even when traveling on a road surface of several tens of degrees below freezing point, and a sound absorbing material made of a porous resin material is used. Can be protected.

  Hereinafter, the present invention will be specifically described with reference to embodiments shown in the drawings.

  FIG. 1 is a cross-sectional perspective view of an essential part of the embodiment of the low-noise pneumatic tire of the present invention showing the inside of the tire.

  In FIG. 1, 10 is a tread portion, 11 is a sidewall portion, and 12 is a bead portion, and an inner liner layer 6 is adhered to the entire tire inner surface of the tread portion 10. A belt-like sound absorbing material 2 made of a polyurethane foam porous resin material is attached to the tire inner peripheral surface 5 on the inner surface of the tire by an elastic fixing band 3 pressed against the inner surface of the tire by an elastic force. A protective sheet 4 made of a thermoplastic elastomer composition in which an elastomer is dispersed in a thermoplastic resin is attached to the inner circumferential surface of the belt-shaped sound absorbing material 2 so as to cover the entire surface.

  In FIG. 1, the band-shaped sound absorbing material 2 includes the elastic fixing band 3 and a protective sheet 4 that covers the tire inner peripheral surface side of the sound absorbing material 2 to form the noise reduction device 1 as shown in FIG. 2. Yes.

As the sound absorbing material 2 made of a porous resin material, a material formed of urethane foam is used .

  The thermoplastic resin constituting the thermoplastic elastomer composition constituting the protective sheet 4 is, for example, a polyamide resin [for example, nylon 6 (N6), nylon 66 (N66), nylon 46 (N46), nylon 11 (N11), Nylon 12 (N12), Nylon 610 (N610), Nylon 612 (N612), Nylon 6/66 copolymer (N6 / 66), Nylon 6/66/610 copolymer (N6 / 66/610), Nylon MXD6 (MXD6), nylon 6T, polyester resin [for example, polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polybutylene naphthalate (PBN), polyvinyl resin [for example, polyvinyl alcohol (PVA), vinyl alcohol / ethylene Copolymer (EVOH) etc. Mashiku can be used.

  The elastomer dispersed in the thermoplastic resin may be, for example, an olefin rubber [for example, ethylene propylene rubber (EPDM, EPM), maleic acid-modified ethylene propylene rubber (M-EPM), butyl rubber (IIR), Halogen rubber [for example, bromide of Br-IIR, CI-IIR, isobutylene paramethylstyrene copolymer (Br-IPMS) and the like can be preferably used. These elastomers are characterized by a low embrittlement temperature compared to the thermoplastic resin.

  In the thermoplastic elastomer composition, the composition ratio between the thermoplastic resin as the matrix component and the elastomer dispersed therein is thermoplastic resin / elastomer = 90 / 10-30 / 70 by weight. preferable.

  Since this composition contains an elastomer having a remarkably low embrittlement temperature as compared with a thermoplastic resin, it is excellent in resistance to embrittlement and heat insulating properties in a low temperature state. Therefore, the low temperature durability of the sound absorbing material made of a porous resin can be improved by being disposed as a protective sheet for the sound absorbing material.

  The form of the protective sheet 4 is not particularly limited, but may be a film or a sheet-like material such as a nonwoven fabric. In the case of a nonwoven fabric, the heat insulation is further improved because air is contained in the sheet. The sheet-like material may be bonded to the porous sound-absorbing material by heat lamination or by heat-bonding them using an adhesive resin such as a low melting point resin or an adhesive. Although the thickness of the protection sheet 4 is not specifically limited, It is preferable to set it as the range of 0.1-1 mm.

  FIG. 3 illustrates the difference in how the protective sheet is attached to the sound absorbing material 2. In the embodiment of FIG. 3A, the protective sheet 4 is arranged over the entire width of the sound absorbing material 2, and the elastic fixing band 3 is arranged outside thereof. On the other hand, in the embodiment of FIG. 3B, an example is shown in which the elastic sheet 3 is covered with the protective sheet 4 over the entire width of the sound absorbing material 2, and any embodiment may be used. When the elastic fixing band 3 is made of a resin material such as polypropylene, the embodiment shown in FIG. 3B is preferable.

Further, the inner liner layer 6, Conventionally, a rubber material such as butyl rubber is generally, in the present invention, composed of a thermoplastic elastomer composition elastomer is dispersed in a thermoplastic resin, its In particular, the thermoplastic elastomer composition having substantially the same composition as that of the protective sheet 4 is used . Thus, by forming the inner liner layer 6 with a thermoplastic elastomer composition, it is possible to suppress the generation of static electricity in the sound absorbing material 2 during traveling.

  FIG. 4 illustrates a method for holding the sound absorbing material with respect to the elastic fixing band. 4 (a), 4 (b), and 4 (c) illustrate the holding method in the order of steps, and a protective sheet 4 and a sound absorbing material 2 are disposed on an elastic fixing band 3 and polypropylene is disposed thereon. The locking chip material 8 made of resin or the like is placed, and the vibration horn 7 of the ultrasonic welder is lowered and pressed from above the locking chip material 8 in order to weld and integrate them (FIG. 4 ( a), (b)). And after the ultrasonic welding process which unifies these members is completed, it can manufacture by pulling up the vibration horn 7 upwards (FIG.4 (c)). Both are integrated at a required place by the ultrasonic welding process as in the ultrasonic welding processing unit 9 shown in FIG. Note that the holding method is not limited to that shown in FIG. 4, and other methods may be adopted.

Example 1, Comparative Example 1, Conventional Example As a tire noise reduction device, urethane foam having a cross-sectional shape of 150 mm × 20 mm was commonly used as the sound absorbing material 2, and the presence or absence of the protective sheet and the material were varied as follows. A total of three types of Example 1, Comparative Example 1 and Conventional Example were manufactured.

  In Example 1, a thermoplastic elastomer composition having a thickness of 0.5 mm and having the composition shown in Table 1 was used as the material for the protective sheet.

  In Comparative Example 1, a sheet (thickness 0.5 mm) made of a polyethylene film was used as the protective sheet.

  In the conventional example, no protective sheet was provided.

  The noise reduction devices of Example 1, Comparative Example 1, and the conventional example are each mounted on a pneumatic tire of tire size 215 / 55R16 95H, assembled with a rim at an air pressure of 150 kPa, and durability at low temperature is as follows. A drum durability test was conducted and evaluated.

  As a result, the distance traveled until cracks occurred in the sound-absorbing material was 40000 km in Example 1, 25000 km in Comparative Example 1, and 22000 km in the conventional example, and the one according to Example 1 has much superior durability. Indicated.

(1) Durability test The pneumatic tire was run at a speed of 80 km / h on a drum having a diameter of 1707 mm, with a load of 828 kgf and an ambient temperature of 30 ° C. below freezing. After every 5000 km travel, the urethane foam sound-absorbing material is visually observed for cracks / damage, and the test ends when it is recognized that a crack or chip of 10 mm or more has occurred, and the distance traveled to the end of the test Was evaluated.

It is a principal part notch sectional view showing an example of the form of the pneumatic tire concerning the present invention equipped with the tire noise reduction device. 1 shows an example of the configuration of a noise reduction device 1 mounted on the inner peripheral surface of a pneumatic tire according to the present invention. FIG. 4 shows an example of the arrangement relationship of a porous sound absorbing material, an elastic fixing band, and a protective sheet with respect to the inner peripheral surface of the pneumatic tire of the present invention. It is explanatory drawing which demonstrated an example of the method of manufacturing the tire noise reduction apparatus 1 integrated with the porous sound-absorbing material, the elastic fixing band, and the protection sheet with which the pneumatic tire of this invention is mounted | worn in process order.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tire noise reduction apparatus 2 Sound absorption material 3 Elastic fixing band 4 Protection sheet 5 Tire inner peripheral surface 10 Tread part 11 Side wall part 12 Bead part

Claims (1)

In a low-noise pneumatic tire in which a band-shaped sound absorbing material made of a porous resin material, which is urethane foam, is attached by an elastic fixing band pressed against the inner peripheral surface of the tire, a thermoplastic resin is provided on the inner peripheral surface side of the sound absorbing material. with elastomer made of thermoplastic elastomer composition dispersed in, strip-shaped sound absorbing material protective sheet of thickness 0.1~1mm covering the entire inner circumferential surface of the tire of the sound absorbing material is arranged, and in the tire An inner liner layer made of a thermoplastic elastomer composition in which an elastomer is dispersed in a thermoplastic resin is disposed on the peripheral surface, and the sound absorbing material protective sheet and the inner liner layer are made of a thermoplastic elastomer composition having substantially the same composition. is configured, and to characterized in that said elastic fixing band and the sound absorbing material are integral with pivotal points by welding process Low-noise pneumatic tire.

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