JP2012020611A - Sound absorber for pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sound absorber for pneumatic tire, which is advantageous for promoting thinning and reducing weight while improving durability, and to provide a method of manufacturing the same.SOLUTION: The sound absorber 10 for pneumatic tire is composed of two belt shape members 12, wherein each belt shape member 12 includes a circular arc part 14 and a connection part 16, and an annular body 18 is composed of two belt shape members 12. The belt shape member 12 has a width longer than thickness and the length longer than this width and is formed with porous sound absorbing materials having elasticity and flexibility. The circular arc part 14 is arranged extending on a single circumference and the annular body 18 includes two circular arc parts 14. The connection part 16 where both ends of circular arc parts 14 are joined mutually in extending direction, and projects inside the radial direction of the single circumference, and the annular body 18 includes two connection parts 16.

Description

  The present invention relates to a silent tool for a pneumatic tire mounted between a tire and a wheel rim.

In a pneumatic tire, one of the causes for generating noise is cavity resonance sound caused by vibration of air filled in the tire.
The 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.

Therefore, in order to reduce noise due to such a cavity resonance phenomenon, a technique for mounting a noise control tool on the inner surface of a pneumatic tire has been proposed (see Patent Document 1).
This sound control device is configured by adhering end surfaces to each other using a double-sided tape or an adhesive in a state in which the end surfaces of a long sponge material arranged along the tire circumferential direction are abutted.

JP 2009-202856 A

However, in the prior art, since the end surfaces of the sponge material are bonded to each other with a double-sided tape or an adhesive, it is necessary to ensure the area of the end surfaces in order to ensure the strength of the bonded portion between the end surfaces. Therefore, it is difficult to reduce the dimension of the sponge material in the thickness direction, which is disadvantageous in reducing the thickness and weight of the sound control device.
The present invention has been made in view of such circumstances, and an object thereof is to provide a silent tool for a pneumatic tire that is advantageous in reducing the thickness and weight while improving the durability. Moreover, it aims at providing the manufacturing method of such a silent tool for pneumatic tires.

In order to achieve the above-described object, the silent device for a pneumatic tire of the present invention is formed of a porous sound-absorbing material having a width larger than the thickness and a length larger than the width, and having elasticity and flexibility. Each of the band-shaped members is joined to an arc portion extending on a single circumference and an end portion of the arc portion adjacent to both ends in the extending direction of the arc portion. And a connecting portion that protrudes radially inward of the single circumference, and an annular body is constituted by the plurality of strip-shaped members.
In addition, the method for producing a silent tool for a pneumatic tire according to the present invention includes a belt-like member made of a porous sound-absorbing material having a width larger than the thickness and a length larger than the width, and having elasticity and flexibility. Preparing two strip members in the thickness direction with their length and width directions matched, joining surfaces facing at both ends in the length direction of the two strip members, and the two strip members, The two arcs extending on a single circumference and the ends in the extending direction of each arc are joined to each other so that the surfaces facing each other are located on the outside except for the ends. And a connecting part protruding radially inward of the single circumference, and producing a silent device for a pneumatic tire in which an annular body is constituted by the two belt-like members.

According to the silencer for a pneumatic tire of the present invention, the plurality of belt-shaped members formed of the porous sound-absorbing material include the arc portion extending on the single circumference and the radially inner side of the single circumference. And a plurality of strip-shaped members that form an annular body.
Therefore, since a plurality of belt-shaped members are joined via the connection portion, even if the thickness direction dimension of the belt-like member is reduced, a large area of the portion to be joined at the connection portion can be secured, and the strength of the connection portion can be increased. Can be secured. Therefore, it is advantageous in reducing the thickness and weight while improving the durability.
Further, according to the method for producing a silent tool for a pneumatic tire of the present invention, two belt-like members are overlapped in the thickness direction, and the faces facing each other at both ends in the length direction of the two belt-like members are joined together. Since it can be easily and reliably manufactured by reversing the above, it is extremely advantageous in reducing the manufacturing cost of the silent tool for a pneumatic tire.

(A) is a front view which shows the silencer 10 for pneumatic tires which concerns on 1st Embodiment, (B) is a perspective view which shows the state with which the two strip | belt-shaped members 12 were joined, (C) is two strip | belt-shaped. It is a figure which shows the state which curvedly deformed the member 12 in circular arc shape. (A), (B) is a top view which shows the state which the connection part 16 displaced to the radial inside of the annular body 18. FIG. (A) is a front view which shows the silencer 10 for pneumatic tires which concerns on the modification of 1st Embodiment, (B) is a figure which shows the state in which the end of the two strip | belt-shaped members 12 was joined. It is a perspective view which shows the state by which the notch 1602 was provided in the connection part 16 of the two strip | belt-shaped members 12 in 2nd Embodiment. (A), (B), (C) is a top view which shows the notch 1602 provided in the connection part 16 of the strip | belt-shaped member 12. FIG. (A) is a front view which shows the silencer 10 for pneumatic tires concerning 3rd Embodiment, (B) is a perspective view which shows the state with which the three strip | belt-shaped members 12 were joined, (C) is three strip | belt-shaped. It is a figure which shows the state which curvedly deformed the member 12 in circular arc shape. (A) is a front view which shows the silencer 10 for pneumatic tires which concerns on 4th Embodiment, (B) is a perspective view which shows the state with which the four strip | belt-shaped members 12 were joined, (C) is four strip | belt-shaped. It is a figure which shows the state which curvedly deformed the member 12 in circular arc shape. It is a figure which shows the result of the evaluation test of the drum running durability of the Example of the silencer 10 for pneumatic tires which concerns on this invention, and a comparative example.

(First embodiment)
Next, embodiments of the present invention will be described with reference to the drawings.
As shown in FIG. 1 (A), the silencer 10 for a pneumatic tire according to the present embodiment includes two belt-like members 12, and each belt-like member 12 includes an arc portion 14 and a connection portion 16. An annular body 18 is constituted by the two belt-like members 12.
The pneumatic tire silencer 10 is mounted between the tire and the rim of the wheel, particularly on the tire inner peripheral surface (tire inner cavity surface), and with respect to the tire inner peripheral surface inside the tread portion when the tire rotates. It is used as a so-called noise reducing material that rotates at a rotational speed slower than the rotational speed of the tire while sliding and suppresses cavity resonance noise during tire rolling.

The band-shaped member 12 has a width larger than the thickness and a length larger than the width, and is made of a porous sound-absorbing material having elasticity and flexibility. In the present embodiment, the thickness, width, and length of the two strip members 12 have the same dimensions.
Conventionally known various materials such as urethane foam and foam rubber can be used as such a porous sound absorbing material. However, in order to effectively suppress damage such as chipping and tearing and deformation such as compression (sagging). A flexible polyurethane foam is preferred.
More specifically, it is preferable that the tear strength (unit: N / cm) per unit density (kg / m ³ ) of the flexible polyurethane foam is 0.15 or more in order to effectively suppress breakage and deformation.
The tear strength per unit density is a value calculated from the measured density and tear strength, and is a value obtained by dividing the tear strength by the density.
Further, the tear strength is a value measured according to JIS K6400-5, assuming that the shape of the test piece is an “angle type test piece without cut”.
Flexible polyurethane foams are broadly classified into, for example, polyester urethane foams, polyether urethane foams, and polyester ether urethane foams, depending on the type of polyol component that is the main raw material.
From the viewpoint of controlling the tear strength per unit density, polyester urethane foam and polyether urethane foam are preferred.
Such a flexible polyurethane foam is available, for example, as a commercially available “Clara Foam” series manufactured by Kurashiki Boseki Co., Ltd.
In addition, the flexible polyurethane foam has good thermal conductivity from the portion of the belt-like member 12 in contact with the inner peripheral surface of the tire to the tire chamber, and is continuous in suppressing heat accumulation on the inner peripheral surface of the tire. It is preferable to have bubbles.

The circular arc portion 14 is arranged so as to extend on a single circumference, and the annular body 18 includes two circular arc portions 14.
The connecting portion 16 has both ends in the extending direction of the arc portions 14 joined to each other and protrudes radially inward of the single circumference, and the annular body 18 includes two connecting portions 16.
The locations of the connecting portions 16 on the radially outer side of the annular body 18 are open outward in the radial direction formed by the outer peripheral surfaces 14A on the radially outer side of the pair of arc portions 14 having an acute angle or an obtuse angle. The concave portion 1602 is formed.
The outer peripheral surface 18A of the annular body 18 is composed of the outer peripheral surface 14A of the two arc portions 14 and the wall surfaces of the two concave portions 1602. The inner peripheral surface 18B of the annular body 18 is the inner peripheral surface 14B of the two arc portions 14 And the wall surfaces of the two connecting portions 16 located inside the annular body 18.

  The shape of the annular body 18 is a force repelling a compressive force generated along the circumferential direction at the inner peripheral portion of the arc portion 14 and a force repelling a tensile force generated along the circumferential direction at the outer peripheral portion of the arc portion 14. And is held by. Therefore, when the silencer 10 for pneumatic tires is inserted inside the tread portion of the tire, it is held in a shape along the tire inner peripheral surface inside the tread portion.

The pneumatic tire silencer 10 can be mounted on tires of various sizes.
That is, as shown in FIGS. 2 (A) and 2 (B), the connecting portion 16 is displaced inward in the radial direction of the annular body 18, so that the annular body constituted by the pair of arc portions 14 and the pair of connecting portions 16. The outer diameter of 18 is reduced, or conversely, the connecting portion 16 is displaced radially outward of the annular body 18 so that the outside of the annular body 18 constituted by the pair of arc portions 14 and the pair of connecting portions 16 is removed. Since the diameter can be expanded, it can be used for tires of various sizes. Therefore, it is advantageous in reducing the cost of the silencer 10 for a pneumatic tire.

The silencer 10 for a pneumatic tire is manufactured as follows.
As shown in FIG. 1B, two belt-like members 12 each having a width larger than the thickness and a length larger than the width and made of a porous sound-absorbing material having elasticity and flexibility are prepared.
Next, the two strip-like members 12 are overlapped in the thickness direction with the length and width directions matched.
And the surface 1202 which faces the both ends of the length direction of the two strip | belt-shaped members 12 is joined. Thereby, the connection part 16 is formed in the both ends of the length direction of the two strip | belt-shaped members 12. FIG.
This bonding is conventionally known, such as bonding with an adhesive or double-sided adhesive tape, welding by thermal welding, bonding by a stapler needle, bonding using a fastener made of a synthetic resin material or a metal material, and bonding by stitching using a thread. Various bonding methods can be used.

Next, as shown in FIG. 1C, the two strip members 12 are deformed in the direction in which the two connecting portions 16 approach, and the strip members 12 facing each other are curved and deformed in an arc shape.
Next, the two belt-like members 12 are reversed so that the surfaces 1204 facing each other are located on the outside except for the both ends.
Thereby, as shown to FIG. 1 (A), the silencer 10 for pneumatic tires provided with the two circular arc parts 14 and the two connection parts 16 is manufactured.

In the above-described method, the two belt-like members 12 are reversed. However, as described below, the tire silencer 10 can be manufactured without inverting the two belt-like members 12.
That is, as shown in FIG. 3B, the two strip members 12 are linearly arranged on the work table T, and adjacent ends of the two strip members 12 are curved and deformed upward to face each other. The connection part 16 is formed by joining.
Next, as indicated by an arrow X in the figure, the remaining portions of the two belt-like members 12 are lifted upward and deformed into an arc shape, and the remaining ends of the two belt-like members 12 are connected to the connecting portion 16 side. The remaining connecting portion 16 is formed by joining the opposing surfaces 1202 of the remaining ends of the two belt-like members 12.
Thereby, as shown to FIG. 3 (A), the silencer 10 for pneumatic tires provided with the two circular arc parts 14 and the two connection parts 16 is manufactured.

As described above, according to the pneumatic tire silencer 10 of the present embodiment, the plurality of belt-like members 12 includes the arc portion 14 extending on a single circumference and the extension of the arc portion 14. A plurality of strip-shaped members 12 form an annular body 18 that includes a connecting portion 16 that is joined to an end portion of the arc portion 14 that is adjacent to both ends in the direction and projects radially inward of a single circumference. Yes.
Therefore, since the plurality of strip-shaped members 12 are joined via the connection portion 16, even if the dimension in the thickness direction of the strip-like member 12 is reduced, the area of the portion joined by the connection portion 16 can be secured large, and the connection The strength of the portion 16 can be ensured. Therefore, it is advantageous in reducing the thickness and weight while improving the durability.

  In addition, the silencer 10 for a pneumatic tire overlaps the two strip members 12 in the thickness direction, joins the faces 1202 facing each other at both ends in the length direction of the two strip members 12, and reverses the two strip members 12. Since it can manufacture easily and reliably by this, it becomes very advantageous when reducing the manufacturing cost of the silencer 10 for pneumatic tires.

The effective outer peripheral length of the pneumatic tire silencer 10 is preferably in the range of 80 to 110%, more preferably in the range of 90 to 100%, of the inner peripheral length when the tire to be inserted is inflated.
The effective outer peripheral length of the pneumatic tire silencer 10 is the circumference of a circle (or ellipse) enveloping the outer periphery of the annular body 18 held in a substantially circular shape, and the inner peripheral length when the tire is inflated is (tire The outer diameter during inflation of the tire-the total gauge of the tire × 2) × π may be obtained.
If the ratio of the peripheral length of the effective outer peripheral length of the pneumatic tire silencer 10 to the inner peripheral length at the time of inflation of the tire is too large, the annular body 18 is compressed in the tire due to the influence of ground contact distortion caused by the rolling of the tire. Therefore, excessive wrinkles and distortion occur, and durability is insufficient.
On the other hand, if the peripheral length ratio of the effective outer peripheral length of the pneumatic tire silencer 10 to the inner peripheral length at the time of inflation of the tire is too small, the annular body 18 is likely to be eccentric from the rolling axis of the tire. It may cause body vibration and abnormal noise.
In the present invention, since the effective outer peripheral length of the pneumatic tire silencer 10 can be adjusted by displacing the connecting portion 16 inward of the annular body 18 in the radial direction, when the pneumatic tire silencer 10 is mounted on a tire. The effective outer peripheral length may be adjusted to a range of 80 to 110% or a range of 90 to 100% of the inner peripheral length at the time of inflation of the tire to be inserted. When the effective outer peripheral length cannot be adjusted within this range, another pneumatic tire silencer 10 having a different effective outer peripheral length (different size) that can be adjusted within this range may be used.

The maximum width of the silencer 10 for a pneumatic tire is preferably in the range of 50 to 100%, more preferably in the range of 70 to 90% of the cross-sectional width of the tire to be inserted.
If the ratio of the maximum width of the pneumatic tire silencer 10 to the tire cross-sectional width is too large, the annular body 18 is compressed in the tire due to the influence of ground contact distortion caused by rolling of the tire. And the durability is insufficient.
On the other hand, if the ratio of the maximum width of the pneumatic tire silencer 10 to the tire cross-sectional width is too small, the degree of freedom in the tire of the annular body 18 becomes excessively high, causing vehicle body vibration and abnormal noise.

The thickness of the belt-like member 12 is preferably in the range of 5 to 30 mm, and more preferably in the range of 10 to 20 mm.
If the thickness of the belt-like member 12 is less than 5 mm, shape retention and durability are insufficient.
On the other hand, when the thickness of the strip-shaped member 12 exceeds 30 mm, there is a disadvantage that the weight increases and the rim assembly property is deteriorated.
For this reason, the thickness of the belt-like member 12 is more preferably in the range of 10 to 20 mm.

(Second Embodiment)
Next, a second embodiment will be described.
In the following embodiments, parts and members similar to those in the first embodiment will be described with the same reference numerals.
Also in 2nd Embodiment, the thickness, width | variety, length, and shape of the two strip | belt-shaped members 12 which comprise the silencer 10 for pneumatic tires shall be the same.
Each belt-like member 12 is configured by an arc portion 14 extending on a single circumference and a connection portion 16 projecting radially inward of the single circumference.
Therefore, strictly speaking, the mass distribution in the circumferential direction of the silencer 10 for a pneumatic tire is constant in the arc portion 14 portion per unit length in the circumferential direction, whereas the portion of the connection portion 16 Then, since the end portions of the two belt-like members 12 are overlapped, the connection portion 16 is larger than the arc portion 14, and the mass distribution in the circumferential direction of the pneumatic tire silencer 10 is biased. .
If there is such a deviation in the mass distribution in the circumferential direction, when the tire rolls, vibration is likely to occur when the connecting portion 16 comes into contact with the ground, and such vibration is caused by high-speed rotation of the tire. It is likely to occur depending on the time.
That is, the deviation in the circumferential mass distribution of the pneumatic tire silencer 10 affects the high-speed uniformity (UF) of the tire on which the pneumatic tire silencer 10 is mounted. In the first embodiment, since two connection portions 16 are provided, the influence of the rotational secondary component of the mass in the high-speed uniformity (UF) appears.
Therefore, in the second embodiment, the high-speed uniformity (UF) of the tire on which the pneumatic tire silencer 10 is mounted is suppressed by suppressing the uneven mass distribution in the circumferential direction of the pneumatic tire silencer 10. We are trying to improve.

As shown in FIG. 4, notches 1602 are provided in the connecting portions 16 formed at both ends in the length direction of the belt-like member 12, and the area per unit length of the connecting portions 16 is per unit length of the arc portion 14. It is formed smaller than the area. In other words, the notch 1602 forms the cross-sectional area of the connecting portion 16 cut along a plane perpendicular to the length direction of the band-shaped member 12 smaller than the cross-sectional area of the arc portion 14.
The cutout 1602 may be provided at both ends in the width direction of the connecting portion 16 as shown in FIG. 5A, or the cutout 1602 may be provided as shown in FIGS. 5B and 5C. You may provide in the intermediate part of the width direction of the connection part 16. As shown in FIG.

The cutout 1602 in the connection portion 16 can be formed by cutting using various conventionally known cutting devices such as a laser cutter, an ultrasonic cutter, a water cutter, a knife, and a press.
When cutting with a laser cutter, it is preferable to use a material having flame retardancy as the porous sound-absorbing material in order to stably perform the cutting process.

According to the second embodiment, by forming the notch 1602 in the connecting portion 16, it is possible to suppress the deviation of the mass distribution in the circumferential direction of the pneumatic tire silencer 10. Therefore, the pneumatic tire silencer 10. This is advantageous in improving the high-speed uniformity (UF) of the tire on which is mounted.
In particular, in the second embodiment, since two connecting portions 16 are provided, improvement of the rotational secondary component of mass in the high-speed uniformity (UF) of the tire on which the silent tire 10 for pneumatic tire is mounted is improved. This is advantageous in achieving this.

(Third embodiment)
Next, a third embodiment will be described.
The third embodiment is different from the first embodiment in that the number of the strip-like members 12 constituting the silent tool 10 for a pneumatic tire is three.
As shown in FIG. 6 (A), the silencer 10 for a pneumatic tire includes three strip members 12, and each strip member 12 includes an arc portion 14 and a connection portion 16 and includes three strip members 12. Thus, the annular body 18 is configured.
Similar to the first embodiment, the belt-shaped member 12 has a width larger than the thickness and a length larger than the width, and is formed of a porous sound-absorbing material having elasticity and flexibility. The strip member 12 has the same thickness, width and length.

The configurations of the arc portion 14, the connection portion 16, and the annular body 18 are the same as those in the first embodiment except that the number of the strip-shaped members 12 is three.
Further, the shape of the annular body 18 is repelled by the force repelling the compressive force generated along the circumferential direction at the inner peripheral portion of the arc portion 14 and the tensile force generated along the circumferential direction at the outer peripheral portion of the arc portion 14. Therefore, when the pneumatic tire silencer 10 is inserted inside the tread portion of the tire, it is held in a shape along the tire inner peripheral surface inside the tread portion. It is the same as the form.
Further, as described with reference to FIGS. 2A and 2B, the pneumatic tire silencer 10 is the same as that of the first embodiment in that it can be attached to tires of various sizes.

The silencer 10 for a pneumatic tire is manufactured as follows.
Three strip-shaped members 12 having a width larger than the thickness and a length larger than the width and made of a porous sound-absorbing material having elasticity and flexibility are prepared.
As shown in FIG. 6B, three strip members 12 are arranged on the work table T in a straight line so that their length directions coincide with each other, and adjacent end portions of the three strip members 12 are placed upward. The two connecting portions 16 are formed by lifting and bending and joining the facing surfaces 1202 together.
Next, as shown by an arrow Y in the figure, the two strip-like members 12 on both sides are curved and deformed so as to approach each other, the unjoined end portions are brought close to each other, and the opposing surfaces 1202 are joined to each other, thereby connecting one connecting portion 16. Form.
Thereby, as shown in FIG.6 (C), the three connection parts 16 face the outer side, and the annular body by which the three strip | belt-shaped members 12 curved inside is comprised.
Next, the three belt-like members 12 are reversed so that the surface 1204 facing the inner side of the annular body is located on the outer side at a place excluding the connecting portion 16.
Accordingly, as shown in FIG. 6 (A), for a pneumatic tire provided with three circular arc portions 14 that are convex on the outer side of the annular body 18 and three connection portions 16 that are convex on the inner side of the annular body 18. The silencer 10 is manufactured.

In the above-described method, the three belt-like members 12 are reversed. However, as described below, the tire silencer 10 can be manufactured without inverting the three belt-like members 12.
That is, as shown in FIG. 6 (B), the two end portions 16 are formed by joining the adjacent surfaces 1202 by lifting and bending the adjacent ends of the three strip-shaped members 12 upward.
Next, as indicated by an arrow X in the figure, the two belt-like members 12 on both sides of the three belt-like members 12 are lifted upward and deformed into an arc shape, and the ends of the two belt-like members 12 on both sides are moved to the remaining portions The connecting portion 16 is formed by bending and deforming to the side of one strip member 12 and joining the facing surfaces 1202 facing the ends of the two strip members 12 on both sides.
As a result, as shown in FIG. 6 (A), the pneumatic tire silencer 10 including the three arc portions 14 and the three connection portions 16 is manufactured.

As described above, according to the pneumatic tire silencer 10 of the third embodiment, the configuration is the same as that of the first embodiment except that three belt-like members 12 are used. The same effects as in the first embodiment are exhibited.
Also in the third embodiment, as in the second embodiment, the notch 1602 is formed in the connecting portion 16, thereby reducing the circumferential mass distribution of the pneumatic tire silencer 10. This is advantageous for improving the high-speed uniformity (UF) of the tire.

(Fourth embodiment)
Next, a fourth embodiment will be described.
The fourth embodiment is different from the first embodiment in that the number of belt-like members 12 that constitute the silent tool 10 for a pneumatic tire is four.
As shown in FIG. 7 (A), the pneumatic tire silencer 10 includes four belt-like members 12, and each belt-like member 12 includes an arc portion 14 and a connection portion 16, and four belt-like members 12. Thus, the annular body 18 is configured.
Similar to the first embodiment, the belt-like member 12 has a width larger than the thickness and a length larger than the width, and is formed of a porous sound-absorbing material having elasticity and flexibility. The strip member 12 has the same thickness, width and length.

The configurations of the arc portion 14, the connection portion 16, and the annular body 18 are the same as those in the first embodiment except that the number of the belt-like members 12 is four.
Further, the shape of the annular body 18 is repelled by the force repelling the compressive force generated along the circumferential direction at the inner peripheral portion of the arc portion 14 and the tensile force generated along the circumferential direction at the outer peripheral portion of the arc portion 14. Therefore, when the pneumatic tire silencer 10 is inserted inside the tread portion of the tire, it is held in a shape along the tire inner peripheral surface inside the tread portion. It is the same as the form.
Further, as described with reference to FIGS. 2A and 2B, the pneumatic tire silencer 10 is the same as that of the first embodiment in that it can be attached to tires of various sizes.

The silencer 10 for a pneumatic tire is manufactured as follows.
Four strip-shaped members 12 having a width larger than the thickness and a length larger than the width and made of a porous sound-absorbing material having elasticity and flexibility are prepared.
As shown in FIG. 7B, four belt-like members 12 are arranged in a straight line on the work table T and the adjacent ends of the four belt-like members 12 are lifted upward to bend and deform to face each other. The three connecting portions 16 are formed by joining the two.
Next, as shown by an arrow Y in the figure, the two strip-like members 12 on both sides are curved and deformed so as to approach each other, the unjoined end portions are brought close to each other, and the opposing surfaces 1202 are joined to each other, thereby connecting one connecting portion 16. Form.
As a result, as shown in FIG. 7C, an annular body is formed in which the four connection portions 16 face outward and the four belt-like members 12 curve inward.
Next, the four belt-like members 12 are reversed so that the surface 1204 facing the inner side of the annular body is located on the outer side at a place excluding the connecting portion 16.
Thus, as shown in FIG. 7A, for a pneumatic tire provided with four arcuate portions 14 convex on the outside of the annular body 18 and four connection portions 16 convex on the inside of the annular body 18. The silencer 10 is manufactured.

In the above-described method, the four belt-like members 12 are reversed. However, as described below, the tire silencer 10 can be manufactured without inverting the four belt-like members 12.
That is, as shown in FIG. 7B, three connection portions 16 are formed in the same manner as described above.
Next, contrary to the above, as indicated by an arrow X in the figure, the two belt-like members 12 on both sides of the four belt-like members 12 are lifted upward to be deformed into an arc shape, and the two belt-like members 12 on both sides are deformed. The connecting portion 16 is formed by bending the end portion toward the remaining two strip-shaped members 12 and joining the opposing surfaces 1202 of the ends of the two strip-shaped members 12 on both sides.
As a result, as shown in FIG. 7A, the pneumatic tire silencer 10 including the four arc portions 14 and the four connection portions 16 is manufactured.

As described above, according to the pneumatic tire silencer 10 of the fourth embodiment, the configuration is the same as that of the first embodiment except that four belt-like members 12 are used. The same effects as in the first embodiment are exhibited.
Also in the fourth embodiment, as in the second and third embodiments, the notch 1602 is formed in the connecting portion 16, so that the mass distribution in the circumferential direction of the silent tool 10 for pneumatic tires is increased. This is advantageous in improving the high-speed uniformity (UF) of the tire.

In the first, third, and fourth embodiments, the case where the number of the belt-like members 14 constituting the silent tool 10 for a pneumatic tire is two, three, and four has been described. Five or more may be sufficient as 14, and the number of the strip | belt-shaped members 14 which comprise the silencer 10 for pneumatic tires is arbitrary.
Further, since the thickness, width, and length of the belt-like member 14 are fixed to predetermined dimensions and mass-produced, and a plurality of types of silencer 10 for pneumatic tires with different numbers of belt-like members 14 to be used can be mass-produced, This is advantageous in reducing the cost of the silencer 10 for entering tires.

Hereinafter, examples of the present invention will be described in comparison with comparative examples.
FIG. 8 is a diagram showing the results of an evaluation test of drum running durability between an example and a comparative example of the silencer 10 for a pneumatic tire according to the present invention.
The test conditions are as follows.
1) Material of silent tire 10 for pneumatic tire:
In Examples 1 to 4, the material of the strip member 12 was a flexible polyurethane foam.
In Comparative Examples 1 and 2, the material of the annular body was a flexible polyurethane foam.
2) Tire specifications:
Tire size: 215 / 60R16 95H
Rim size: 17 × 7JJ
Air pressure: 120 kPa (Low pressure condition about half of normal)
3) Drum running conditions:
Load: 6.8kN (100% of load index value LI)
Drum diameter: 1707mm
Travel speed: 81km / h
4) Evaluation method:
The running distance at the time when it was confirmed by visual observation that the appearance of the silent tool for a pneumatic tire was so damaged that it could not be used was defined as the drum running durability.
Moreover, it was determined by visual observation whether or not the shape of the silent tool for a pneumatic tire maintained an annular shape extending along the tire inner peripheral surface.
Check the appearance of the pneumatic tire silencer by stopping driving every 100 km until the 1000 km run and visually observing the inside of the tire, and after 1000 km, stop driving every 500 km and visually check the inside of the tire. I went there.

Among the items described in FIG. 8, “thickness” is a value indicating the thickness of the band-shaped member 12 by an index.
Further, the “peripheral length ratio” indicates a peripheral length ratio Co / Ci represented by the effective outer peripheral length Co of the annular body 18 / the tire inner peripheral length Ci.
The “maximum width ratio” refers to the maximum width ratio Wc / Wt indicated by the maximum width Wc of the annular body 18 / the tire cross-sectional width Wt.
The “mass” is a value indicating the mass of the silent tool for a pneumatic tire as an index.
In addition, “shape retention” means whether or not the shape of the silent tool for a pneumatic tire is visually maintained to maintain an annular shape extending along the tire inner peripheral surface. ○, if the shape is not retained, it is indicated by a symbol x.

Comparative Example 1 corresponds to the prior art, in which an annular body is formed by performing a step of abutting both end faces of the strip plate in the longitudinal direction and bonding them with an adhesive.
Thickness is index 100, circumference ratio is 95% and within the range of 90-100%, maximum width ratio is 85% and within the range of 70-90%, mass Is an index of 95.

Comparative Example 2 has the same structure as Comparative Example 1.
The thickness is index 80, the circumference ratio is 95% and is in the range of 90-100%, the maximum width ratio is 85%, in the range of 70-90%, and the mass Is an index of 76.

Examples 1 to 4 correspond to the first embodiment, and the silent tool for a pneumatic tire is composed of two belt-like members 12.
In Example 1, the thickness is an index of 100, the circumference ratio is 95% and is in the range of 90 to 100%, the maximum width ratio is 85% and is in the range of 70 to 90%. The mass is an index of 100.

  In Example 2, the thickness is an index of 80, the circumference ratio is 95% and is in the range of 90 to 100%, the maximum width ratio is 85% and is in the range of 70 to 90%. The mass is an index of 80.

  In Example 3, the thickness is an index of 100, the circumference ratio is 115% and exceeds the range of 80 to 110%, and the maximum width ratio is 85% and is within the range of 70 to 90%. The mass is index 120.

  In Example 4, the thickness is an index of 100, the circumference ratio is 95% and is in the range of 90 to 100%, and the ratio of the maximum width is 110%, which exceeds the range of 50 to 100%. The mass is index 124.

Examples 1 and 2 are more durable than Comparative Examples 1 and 2.
In Example 1 and Comparative Example 1, the ratios of thickness, circumference cost, and maximum width are the same and the masses are almost the same, but the drum running durability of Comparative Example 1 is only 2500 km. It can be seen that Example 1 is excellent at 6000 km.
Further, Example 2 and Comparative Example 2 have the same ratio of peripheral cost and maximum width, and have substantially the same mass, but the thickness is an index of 20 compared to Example 1 and Comparative Example 2. thin.
While the drum running durability of Comparative Example 1 remains at 300 km, Example 2 is excellent at 4000 km. This is because the thickness of Comparative Example 2 is an index of 20 less than that of Example 1 and Comparative Example 1, so that the area of the end face of the sponge material cannot be sufficiently secured, and the strength of the joint portion between the end faces is weak. it is conceivable that.
Moreover, since Example 1 has a thickness that is 20 larger than that of Example 2, the durability is more excellent.
Since the circumference ratio is 115% and exceeds the range of 80 to 110% in Example 3, the drum running durability is superior to that of Comparative Examples 1 and 2, but is higher than that of Examples 1 and 2. Slightly decreased.
In Example 4, since the ratio of the maximum width is 110% and exceeds the range of 50 to 100%, the drum running durability is superior to those of Comparative Examples 1 and 2, but from Examples 1 and 2. Is also slightly lower.

  DESCRIPTION OF SYMBOLS 10 ... Silent tool for pneumatic tires, 12 ... Band-shaped member, 14 ... Arc part, 16 ... Connection part, 1602 ... Notch, 18 ... Ring body.

Claims (10)

It has a width greater than the thickness and a length greater than this width, and consists of a plurality of band-shaped members formed of a porous sound-absorbing material having elasticity and flexibility,
Each of the belt-shaped members is joined to an arc portion extending on a single circumference and ends of the arc portion adjacent to both ends in the extending direction of the arc portion. A connecting portion projecting radially inward, and an annular body is constituted by the plurality of strip-shaped members,
A silent tool for a pneumatic tire. Notches are provided in the connection part, and the area per unit length of the connection part is smaller than the area per unit length of the arc part,
The silent tool for a pneumatic tire according to claim 1. The notches are provided at both ends in the width direction of the connection portion,
The silent tool for a pneumatic tire according to claim 2. The notch is provided at an intermediate portion in the width direction of the connection portion.
The silent tool for a pneumatic tire according to claim 2. The outer peripheral length that envelops the outer periphery of the annular body is in the range of 80 to 110%, more preferably in the range of 90 to 100% of the inner peripheral length when the tire to be inserted is inflated.
The silent tool for a pneumatic tire according to any one of claims 1 to 4, characterized in that: The maximum width of the silent tool for a pneumatic tire is in the range of 50 to 100% of the cross-sectional width of the tire to be inserted, and more preferably in the range of 70 to 90%.
The silent tool for a pneumatic tire according to any one of claims 1 to 5. The thickness of the band-shaped member is in the range of 5 to 30 mm, more preferably in the range of 10 to 20 mm.
The silent tool for a pneumatic tire according to any one of claims 1 to 6, characterized in that The porous sound-absorbing material is a flexible urethane foam having a tear strength (N / cm) per unit density (kg / m ³ ) of 0.15 or more.
The silent tool for a pneumatic tire according to any one of claims 1 to 7. The flexible urethane foam has open cells,
The silent tool for a pneumatic tire according to claim 8. Two strip-shaped members made of a porous sound-absorbing material having a width larger than the thickness and a length larger than this width and having elasticity and flexibility are prepared,
The two belt-like members are overlapped in the thickness direction so that the length and width directions coincide with each other,
Joining opposite surfaces at both ends in the length direction of the two strip members;
Invert the two band-like members so that the surfaces facing each other are located on the outside, except for the ends.
Two arc portions extending on a single circumference, and connecting portions projecting radially inward of the single circumference by joining both ends in the extending direction of the arc portions to each other, Producing a silencer for a pneumatic tire in which an annular body is constituted by the two belt-like members;
A method for manufacturing a silent tool for a pneumatic tire.

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