JP2009046068A - Pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire for previously giving information to a driver about such a probability that sound absorbing layers arranged on inner faces of a sidewall and a bead are separated from the inner face of the pneumatic tire. <P>SOLUTION: The pneumatic tire comprises the sound absorbing layers 11 formed of porous materials and arranged on the inner face of an inner liner 10 in at least part of an inner face region on the sidewall 3 and the bead 4 of the tire body. On the inner face of the inner liner 10, there are provided a pressure sensor 14 for detecting pressure in the tire 1 and a transmitting means 15 for transmitting a signal detected by the pressure sensor 14 to the outside of the tire 1. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a pneumatic tire that reduces vehicle interior noise, and in particular, a sound absorbing layer that reduces cavity resonance generated by vibration of air filled in a tire lumen defined by a pneumatic tire and a rim. Relates to a pneumatic tire comprising

  A pneumatic tire assembled in a rim and attached to a vehicle generates a cavity resonance of air filled in the tire lumen when the tread portion vibrates against the road surface unevenness while the vehicle is running. This cavity resonance is a main cause of so-called road noise, and many of the resonance frequencies exist in the range of 180 to 300 Hz. Unlike the noise in other frequency bands, the road noise takes a sharp and high peak value when transmitted to the vehicle interior, and thus becomes annoying noise for passengers in the vehicle interior.

  In order to suppress such cavity resonance and reduce road noise, Patent Document 1 discloses a belt-like sound absorbing layer for absorbing sound using a sponge material in a tire lumen formed by a rim and a pneumatic tire attached to the rim. Is fixed in the tire circumferential direction, and the sound absorbing layer has a volume S2 in which the ratio S2 / S1 to the total volume S1 of the tire lumen is 0.4% or more, and the sponge material has a specific gravity. 0.005 to 0.06, and the surface of the sound absorbing layer facing the tire lumen is an uneven surface, and the uneven surface includes a protruding convex portion and a concave concave portion in the tire circumferential direction or the tire. An assembly of a pneumatic tire and a rim has been proposed which is characterized by repeating the unevenness by interspersing without aligning the position in the axial direction.

  However, in the conventional pneumatic tire described in Patent Literature 1, the sound absorbing layer is attached to the inner surface of the tread portion. There is a problem that not only the puncture repair agent penetrates and the sound absorbing effect is remarkably lowered, but also the uniformity deteriorates due to the penetration of the puncture repair agent. Furthermore, when a failure such as a puncture occurs in the tread portion, the repair work for the failed portion is complicated and cannot be quickly repaired. In other words, a pneumatic tire having a sound absorbing layer can be buffed with a grinder or the like until the inner liner is exposed after removing the sound absorbing layer around the failed portion in advance in addition to the normal repair work in the repairing operation of the failed portion. It is necessary to work to smooth the surface with scissors, crusher, etc., and afterwards, it is necessary to attach the sound absorbing layer again to the part where the sound absorbing layer has been removed. It will take time and effort.

  Therefore, by arranging the sound absorbing layer at a place other than the inner surface of the tread part, specifically, the inner surface of the sidewall part and the bead part, puncture due to nailing or the like mainly occurs in the tread part. The problem of the reduction in the sound absorption effect as described above and the problem of complexity when repairing the failure part are solved.

Japanese Patent No. 3622957

  However, if the sound absorbing layer is disposed on the inner surface of the sidewall portion and the bead portion instead of the inner surface of the tread portion, the deflection deformation of the tire increases when the internal pressure of the tire decreases due to long-term use, etc. It has been found that there is a risk of peeling from the tire inner surface. For such a problem of peeling of the sound absorbing layer, measures such as strengthening the adhesion between the tire inner surface and the sound absorbing layer or attaching the sound absorbing layer to the tire inner surface without wrinkles are taken. However, it has not yet reached a fundamental solution.

  Accordingly, an object of the present invention is to solve the above-described problems, and the object thereof is that the sound absorbing layer disposed on the inner surfaces of the sidewall portion and the bead portion is caused by a decrease in the internal pressure of the pneumatic tire. Then, it is providing the pneumatic tire which can notify a driver | operator etc. beforehand about the probability of peeling from the inner surface of a pneumatic tire.

  In order to achieve the above object, the present invention provides a sound absorbing layer made of a porous material on an inner surface of an inner liner and at least a part of an inner surface region of a sidewall portion and a bead portion of a tire body. The pneumatic tire is provided with a pressure sensor for detecting an internal pressure of the pneumatic tire on the inner liner inner surface, and a transmission means for transmitting a signal detected by the pressure sensor to the outside of the pneumatic tire. This is a pneumatic tire. By adopting such a configuration, the internal pressure of the pneumatic tire is detected by the pressure sensor, and the detected signal is transmitted to the outside of the pneumatic tire by the transmission means. For example, by detecting this signal with a detection unit or the like on the vehicle body side, the driver or the like can know the change in the internal pressure of the pneumatic tire. Here, the peeling of the sound absorbing layer is caused by the deflection deformation of the pneumatic tire that occurs during traveling, and further, this deflection deformation increases with a decrease in the internal pressure, and thus, by knowing the internal pressure of the tire, It is possible to know the probability that the sound absorbing layer peels from the inner surface of the pneumatic tire. Therefore, when the internal pressure of the tire decreases, it is possible to suppress an increase in the deflection deformation of the sidewall portion and the bead portion during running by appropriately filling the tire with air so that the predetermined air pressure is obtained. Layer peeling can be prevented.

  In the present specification, the “inner surface region of the sidewall portion and the bead portion” means a region from the inner surface of the tread ground end to the bead toe, and the “tread ground end” is described in the following standard. Install the tire on the standard rim (or “Approved Rim”, “Recommended Rim”) at the applicable size, apply the highest air pressure specified in the standard in the tire, place it in a stationary state perpendicular to the flat plate, and load the maximum This is the outermost end in the tire width direction at the contact surface with the flat plate when a load (in the case of a passenger car pneumatic tire, a load corresponding to 88% of the maximum load capacity) is applied. The “inner surface of the tread ground contact end” referred to here is an intersection of the perpendicular line drawn from the tread ground contact end to the contour line (periphery) of the tire inner surface and the tire inner surface as seen in the cross section in the tire width direction. The standard refers to an industrial standard that is valid in the region where tires are produced or used. For example, the “Year Book” of The Tire and Rim Association Inc. in the United States, and the European Tire and Rim Technical Organization in Europe. "Standards Manual", and in Japan it is the "JATMA Year Book" of the Japan Automobile Tire Association. The air here can be replaced with an inert gas such as nitrogen gas.

  It is preferable that the pressure sensor and the transmission unit are arranged at a center position in the tire width direction.

  According to the present invention, since a decrease in the internal pressure of the tire can be known as appropriate, the probability of peeling from the inner surface of the inner liner of the sound absorbing layer disposed in at least a part of the inner surface region of the sidewall portion and the bead portion is improved. The driver can be notified in advance.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a cross section in the tire width direction of a tire / rim assembly formed by mounting a typical pneumatic tire (hereinafter referred to as “tire”) according to the present invention on a standard rim, and shows the maximum load and the maximum load. It is sectional drawing shown in the grounding state on the conditions which applied corresponding air pressure.

  As shown in FIG. 1, a tire 1 of the present invention includes a tread portion 2 that contacts a road surface, a pair of sidewall portions 3 that extend inward in the tire radial direction from both sides of the tread portion 2, A pair of bead portions 4 provided in the tire radial direction of the wall portion 3 and fitted to the rim R constitute a tire main body portion 5. Inside the tire body 5 is a toroidal structure between the bead cores 6 and 6 embedded in each bead to form a skeleton structure of the tire body 5, for example, a radial carcass 7 and a crown of the carcass 7. A belt 8 that reinforces the tread portion 2 is disposed on the outer peripheral side of the region. An air-impermeable inner liner 10 is disposed on the inner surface side of the tire body 5, that is, the side facing the tire lumen 9 defined by the tire 1 and the rim R.

  On the inner surface of the inner liner 10, a sound absorbing layer 11 made of a porous material is formed on the inner surface region of the sidewall portion 3 and the bead portion 4 (that is, the vertical line L and the inner surface that are lowered from the tread ground end 12 to the inner surface of the inner liner 10. The region between the inner surface of the tread grounding end and the bead toe 13 corresponding to the intersection with the inner surface of the liner 10 is disposed on the inner surface of at least a part of the inner liner. As a result, the vibration energy of the filled air accompanying the cavity resonance generated in the tire lumen 9 is converted into the internal vibration energy of the porous material constituting the sound absorbing layer 11 and consumed as heat energy, thereby reducing the cavity resonance noise. Has achieved.

  The porous material constituting the sound absorbing layer 11 is a foamed material having open cells or closed cells formed by foaming rubber or synthetic resin, or a woven material in which animal fibers, plant fibers, synthetic fibers, etc. are intertwined and integrated. Cloth, non-woven fabric, knitted fabric, or the like can be used. If, for example, synthetic rubber is used as the porous material, the heat-absorbing layer 11 can also be provided with excellent heat resistance and water resistance, and if an ether-based polyurethane foam is used, the foamed material is hardly hydrolyzed. it can.

  The sound absorbing layer 11 can be fixed to the inner liner 10. For this fixing, for example, heat welding, an adhesive, a double-sided tape, a hook-and-loop fastener, or the like can be used. Further, when the sound absorbing layer is fixed in a raw tire state, vulcanization bonding can also be used.

  The main structural features of the present invention are a pressure sensor 14 for detecting the internal pressure of the tire 1 on the inner surface of the inner liner 10, and a transmission means for sending a signal detected by the pressure sensor 14 to the outside of the tire 1. The transmitter 15 is provided.

  The pressure sensor 14 is a detection sensor that detects the internal pressure of the tire 1, and a known semiconductor pressure sensor or a capacitive pressure sensor that detects gauge pressure, differential pressure, or absolute pressure can be used. The transmitter 15 may be a battery-less one using a so-called transponder that transmits the detected internal pressure of the tire 1 by radio waves using an electromotive force induced by an excitation radio wave as a power source, in addition to one driven by a battery. The pressure signal from the pressure sensor 14 is well transmitted to the outside of the tire 1. Although not shown in the figure, a receiver having an antenna is provided on the vehicle body side, and when a radio wave indicating a detection signal of the pressure sensor 14 is transmitted from the transmitter 15 to the receiver via the antenna. The radio wave is received, and for example, the internal pressure of the tire 1 is displayed on a display unit (not shown) provided on the vehicle body side. Alternatively, when the internal pressure of the tire 1 becomes smaller than a predetermined air pressure, the display unit may display a warning or emit a warning sound to notify the driver of a decrease in the internal pressure of the tire 1. . And since the driver | operator etc. can know successively the internal pressure fall of the tire 1, the internal pressure management of the tire 1 can be performed reliably. The “predetermined air pressure” here is the above-mentioned standard (“Year Book” of The Tire and Rim Association Inc. in the United States, and “Standards Manual” of The European Tire and Rim Technical Organization in Europe. In Japan, it is specified in the “JATMA Year Book” of the Japan Automobile Tire Association, etc.), and it is the air pressure specified according to the load capacity.

  According to the tire of this embodiment, the internal pressure of the tire 1 is detected by the pressure sensor 14, and the detected signal is sent by the transmitter 15 to the outside of the tire 1, that is, to the receiver on the vehicle side. Then, by receiving this signal with the receiver on the vehicle body side and displaying it on the display unit, the driver can know the decrease in the internal pressure of the tire 1 and the probability of peeling of the sound absorbing layer 11. That is, as described above, when the tire rolls under load, the tire undergoes elastic deformation (deflection deformation) in one rotation of the tire, and this deflection deformation mainly occurs in the vicinity of the sidewall portion 3 and the bead portion 4. appear. Further, this deflection deformation increases as the internal pressure of the tire 1 decreases. If the sound absorbing layer 11 is disposed on the inner surface of the tread portion 2, the influence of the bending deformation on the sound absorbing layer is small, but the tread portion 2 is applied from the viewpoint of applying the puncture repair agent to the inner surface of the tread portion 2 and facilitating the puncture repair work. It is preferable to dispose in the inner surface area of the sidewall portion 3 and the bead portion 4 instead of the inner surface. Therefore, when the sound absorbing layer 11 is disposed on the inner surfaces of the sidewall portion 3 and the bead portion 4, the probability that the sound absorbing layer 11 is peeled off from the inner liner 10 inner surface of the tire 1 by knowing the internal pressure of the tire 1 in this way. I can know. Therefore, for example, when the internal pressure of the tire 1 drops below a predetermined air pressure, the tire 1 is appropriately filled with air so that the predetermined air pressure is obtained, so that the side wall portion 3 and the bead portion 4 during running can be Since an increase in flexural deformation can be suppressed, it is also possible to prevent the sound absorbing layer 11 from peeling off.

  As shown in FIG. 1, the pressure sensor 14 and the transmitter 15 are preferably disposed on the inner liner inner surface of the tire 1 and at the center position in the tire width direction. By arranging in this way, during the rolling of the load, the pressure sensor 14 and the transmitter 15 are less affected by the bending deformation of the tire 1 and the centrifugal force works stably. There is no risk of falling off or being damaged.

  Further, based on detection signals from the pressure sensor 14 and the transmitter 15, the internal pressure of the tire 1 is preferably maintained at 98% or more of the predetermined air pressure. This is because when the internal pressure of the tire 1 is reduced to less than 98% of the predetermined air pressure, the deflection deformation of the tire 1 increases, and the sound absorbing layer 11 is easily peeled off.

  The above description shows only some of the embodiments of the present invention, and these configurations can be combined with each other or various modifications can be made without departing from the spirit of the present invention. For example, an internal pressure is managed by adding an automatic pressure supply means for automatically supplying pressure to the tire 1 so that the internal pressure of the tire 1 becomes a predetermined air pressure based on a signal from the transmitter 15 on the vehicle side. May be.

  Next, tires according to the present invention were prototyped and performance evaluations were performed, which will be described below.

  The tire of Example 1 has a tire size of 215 / 45R17. As illustrated in FIG. 1, the fineness is 6 dtex and the thickness is partially on the inner peripheral surface of the inner liner of the sidewall portion and the bead portion. A polyethylene terephthalate (PET) nonwoven fabric having a width of 14 mm and a width of 50 mm is disposed as a sound absorbing layer. These sound absorbing layers are bonded to the inner surface of the inner liner with a chloroprene adhesive. Further, the tire of Example 1 is a pressure sensor that detects the internal pressure of the tire at the center position in the tire width direction on the inner surface of the inner liner, and a transmission unit that sends a signal detected by the pressure sensor to the outside of the tire. And a detection signal indicating the tire internal pressure detected by the pressure sensor is transmitted to a vehicle-side receiver.

  For comparison, it does not have the tire, pressure sensor, and transmitter of Comparative Example 1 that have the same configuration as the tire of Example 1, except that it does not have a sound absorbing layer, a pressure sensor, and a transmitter. A tire of Comparative Example 2 having the same configuration as that of the tire of Example 1 was also manufactured.

  Each of the test tires is mounted on a rim of size 17 × 7 J to form a tire wheel, and the tire wheel is attached to a test vehicle, an air pressure of 210 kPa (relative pressure) and a tire load load of 3.92 kN are applied, and a speed of 60 km / A professional driver evaluated the interior noise when driving on an asphalt surface under the condition of h. The evaluation results are shown in Table 1. In addition, the evaluation result in a table | surface shows that it is quiet, so that the suppression effect of cavity resonance is large, so that a numerical value is large.

  Each of the test tires is attached to a rim of size 17 × 7J to form a tire wheel, and the tire is attached to a test vehicle, and an air pressure of 210 kPa (relative pressure) and a tire load load of 3.92 kN are applied. The general road was run for months, and the presence or absence of peeling of the sound absorbing layer was investigated. The survey results are shown in Table 1. For the tire of Example 1, the tire internal pressure is 98% or more of the predetermined air pressure, that is, the air pressure is 205.8 kPa (relative pressure) or more, based on the signal indicating the tire internal pressure transmitted from the transmitter. The air pressure is managed sequentially.

  From the results shown in Table 1, it was found that in the tires of Example 1 and Comparative Example 2 having the sound absorbing layer, cavity resonance was suppressed. Moreover, it was confirmed that peeling of the sound absorbing layer can be suppressed by providing a pressure sensor and a transmitter and sequentially managing the internal pressure.

  As is apparent from the above description, according to the present invention, the pneumatic system can notify the driver or the like in advance of the probability that the sound absorbing layer disposed on the inner surface of the sidewall portion and the bead portion will peel off from the inner surface of the pneumatic tire. It became possible to provide tires.

A cross section in the tire width direction of a tire and rim assembly constituted by mounting a typical pneumatic tire according to the present invention on a standard rim is shown in a ground contact state under a condition where a maximum load and an air pressure corresponding to the maximum load are applied. It is sectional drawing shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tire 2 Tread part 3 Side wall part 4 Bead part 5 Tire main-body part 6 Bead core 7 Carcass 8 Belt 9 Tire lumen 10 Inner liner 11 Sound absorption layer 12 Tread grounding end 13 Bead toe 14 Pressure sensor 15 Transmitter R rim

Claims (2)

On the inner surface of the inner liner, in a pneumatic tire comprising a sound absorbing layer made of a porous material in at least a part of the inner surface region of the sidewall portion and the bead portion of the tire body,
A pressure sensor for detecting an internal pressure of the pneumatic tire on the inner liner inner surface;
Transmitting means for sending a signal from the pressure sensor to the outside of the pneumatic tire.   The pneumatic tire according to claim 1, wherein the pressure sensor and the transmission unit are arranged at a center position in a tire width direction.

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