WO2021117283A1

WO2021117283A1 - Tire

Info

Publication number: WO2021117283A1
Application number: PCT/JP2020/027287
Authority: WO
Inventors: 耕平佐橋
Original assignee: 株式会社ブリヂストン
Priority date: 2019-12-13
Filing date: 2020-07-13
Publication date: 2021-06-17
Also published as: JP2021094879A; JP7409856B2

Abstract

A tire (1) is provided with an annular groove (4) that partitions a tread surface (2a) of a tread (2) into a pair of annular land sections (3), the tire (1) including: a pin sipe (11) provided on the tread surface (2a) of the tread (2); a first sipe (13) and a second sipe (14) which are each provided on the tread surface (2a) of the tread (2) and connect to the pin sipe (11); and a constricted groove (12) that is provided on the tread surface (2a) of the tread (2) and has one end connected to the annular groove (4) and another end connected to the pin sipe (11), thereby constituting a Helmholtz resonator (10) together with the pin sipe (11), the first sipe (13), and the second sipe (14). From among a first angle (θ1) formed by the first sipe (13) and the constricted groove (12), a second angle (θ2) formed by the second sipe (14) and the constricted groove (12), and a third angle (θ3) formed by the first sipe (13) and the second sipe (14), at least two of the angles are obtuse angles.

Description

tire

The present invention relates to a tire.

Conventionally, as a tire mounted on a vehicle such as an automobile, an annular groove (mainly in the circumferential direction) divided into a pair of annular land portions extending in the tire circumferential direction over the entire circumference of the tread on the tread surface of an elastic tread. Those having a structure provided with a groove) are known.

With such tires, noise due to air column resonance is generated between the road surface and the annular groove when the vehicle is running. Therefore, a technique has been developed in which a Helmholtz type resonator is provided on the tread tread to reduce the noise and improve the quietness of the tire.
For example, in Patent Document 1, a branch groove connected to an annular groove and an auxiliary groove connected to the branch groove and having a larger volume than the branch groove are provided on the tread surface of the tread, and the branch groove and the auxiliary groove are provided when the vehicle is running. A tire is described in which a tread opening to the tread is blocked by a road surface to form a Helmholtz-type resonator having a constricted passage connected to an annular groove and an air chamber.

Japanese Unexamined Patent Publication No. 2015-171835

However, in the above-mentioned conventional tire, the sub-groove that is blocked by the road surface to form an air chamber has a shape in which the groove depth is shallow with respect to the groove length, so that the sub-groove having a predetermined volume is formed on the tread surface of the tread. When the tire is provided, the ratio of the opening area of the sub-groove to the tread surface of the tread becomes relatively large, and there is a problem that the contact area of the tread with the road surface decreases by that amount. ..

An object of the present invention is to provide a tire capable of increasing the contact area of a tread provided with a Helmholtz type resonator on the road surface.

The gist structure of the present invention is as follows.
The tire of the present invention
A tire in which an annular groove is provided on the tread surface of an elastic tread, which is divided into a pair of annular land portions extending in the tire circumferential direction over the entire circumference of the tread.
A pin sipe provided on the tread of the tread,
The first sipe and the second sipe, which are provided on the tread of the tread and are connected to the pin sipe, respectively.
A constriction groove provided on the tread surface of the tread, one end of which is connected to the annular groove and the other end of which is connected to the pin sipe to form a Helmholtz type resonator together with the pin sipe, the first sipe and the second sipe. Have,
At least two of the first angle formed by the first sipe and the stenotic groove, the second angle formed by the second sipe and the stenotic groove, and the third angle formed by the first sipe and the second sipe. One is characterized by an obtuse angle.

In the above, the "tread tread" is a state in which a tire assembled on the applicable rim (in the case of a pneumatic tire, a tire in a state where the specified internal pressure is further filled) is subjected to a load corresponding to the maximum load capacity. It means a part that comes into contact with the road surface when it is rolled on the road surface.
Here, the above "applicable rim" is an industrial standard that is effective in the area where tires are produced and used. In Japan, JATMA (Japan Automobile Tire Association) JATMA YEAR BOOK, and in Europe, ETRTO (The European Tire). STANDARDS MANUAL of andRim Technical Organization), YEAR BOOK of TRA (The Tire and Rim Association, Inc.) in the United States, etc. In addition to the current size, the above-mentioned "applicable rim" also includes a size that may be included in the above-mentioned industrial standard in the future. As an example of "size to be tired", the size described as ETRTO Experimental Standard can be mentioned.) However, in the case of a size not described in the above industrial standard, a rim having a width corresponding to the bead width of the tire is used. Say.
In addition, the "specified internal pressure" refers to the air pressure (maximum air pressure) corresponding to the maximum load capacity of a single wheel in the applicable size / ply rating described in the above JATMA, etc., and is of a size not described in the above industrial standard. In this case, the "specified internal pressure" shall mean the air pressure (maximum air pressure) corresponding to the maximum load capacity specified for each vehicle on which the tires are mounted.

According to the present invention, it is possible to provide a tire capable of increasing the contact area of the tread provided with the Helmholtz type resonator on the road surface.

It is a development view of a part of the tread tread of the tire which concerns on one Embodiment of this invention. It is a figure which shows the Helmholtz type resonator shown in FIG. 1 in an enlarged view. It is sectional drawing which follows the AA line in FIG. It is sectional drawing which follows the line BB in FIG. FIG. 2 is a cross-sectional view taken along the line CC property in FIG. It is a figure which shows the Helmholtz type resonator of a modification. It is a figure which shows the Helmholtz type resonator of another modification.

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

The tire 1 according to the embodiment of the present invention shown in FIG. 1 is used, for example, by being mounted on a passenger car.

Tire 1 is provided with an elastic tread 2. The tread 2 can be made of, for example, a material mainly composed of rubber.

The tread 2 includes a pair of annular land portions 3 extending in the tire circumferential direction over the entire circumference of the tread 2. The outer peripheral surfaces of the pair of annular land portions 3 each form a part of the tread surface 2a of the tread 2.

The tread surface 2a of the tread 2 is divided into a pair of annular land portions 3 and provided with an annular groove (circumferential main groove) 4. The annular groove 4 extends continuously along the tire circumferential direction over the entire circumference of the tread 2 and opens to the tread surface 2a of the tread 2.
The annular groove 4 may have a substantially trapezoidal cross section, for example, having a pair of side surfaces and a bottom surface, but the cross-sectional shape may be another shape such as a U shape. The cross-sectional shape of the annular groove 4 is substantially uniform over the entire circumference in the circumferential direction.

The annular groove 4 is not limited to the form extending along the tire circumferential direction (straight line in the developed view), and may be formed in a zigzag shape or a wavy shape, for example.

The groove width of the annular groove 4 (opening width in the tire width direction) is not particularly limited, but can be, for example, 2 to 18 mm. The groove depth (maximum depth in the tire radial direction) of the annular groove 4 is not particularly limited, but may be, for example, 5 to 9 mm.

The annular groove 4 can be provided in the center of the tread 2 in the tire width direction, for example, but the position of the annular groove 4 in the tire width direction can be changed in various ways. Further, the shape of the pair of annular land portions 3 can be changed in various ways.

As shown in FIG. 1, in the present embodiment, the tread surface 2a of the tread 2 is further provided with an auxiliary land portion 5 separate from the pair of annular land portions 3, and the annular land portion 3 and the auxiliary land portion 5 are provided. A sub-annular groove 6 other than the annular groove 4 is formed in between.
The tire 1 may have a configuration in which at least a pair of annular land portions 3 and one annular groove 4 partitioned between the pair of annular land portions 3 are provided on the tread surface 2a of the tread 2. It is also possible to have a configuration in which the secondary land portion 5 or the secondary annular groove 6 is not provided. Further, even when the sub-land portion 5 and the sub-annular groove 6 are provided, the number, shape, and the like thereof can be variously changed. Further, the sub-land portion 5 may be configured to be provided with another groove such as a lug groove.

The tire 1 can be configured as, for example, a pneumatic tire.
The pneumatic tire includes, for example, in addition to the tread 2, a pair of sidewall portions connected to both side portions of the tread 2 and a pair of bead portions provided on the inner peripheral edge portions of the corresponding sidewall portions. It can be configured.
Further, the pneumatic tire may be configured to include, for example, a carcass having a radial structure extending in a toroidal shape between a pair of bead portions and a belt arranged on the radial outer side of the carcass as an internal structure. it can.

The tire 1 is not limited to a pneumatic tire, and can be a non-pneumatic tire such as a solid tire as long as it has an elastic tread 2.

The tread 2 is provided with a Helmholtz type resonator 10.
In the present embodiment, a plurality of Helmholtz-type resonators 10 are provided in the annular land portion 3 between the annular groove 4 and the sub-annular groove 6 of the tread 2 at intervals in the circumferential direction. Although only two Helmholtz-type resonators 10 are shown in FIG. 1, a plurality of Helmholtz-type resonators 10 are provided side by side at equal intervals in the circumferential direction over the entire circumference of the tread 2. Has been done.

As shown in FIG. 2, the Helmholtz type resonator 10 has a pin sipe 11, a constriction groove 12, a first sipe 13 and a second sipe 14. The narrowing groove 12, the first sipe 13, and the second sipe 14 are arranged in a trifurcated shape about the axis of the pin sipe 11.

The pin sipe 11 is provided on the tread surface 2a of the tread 2.

Here, the "pin sipe" has a concave shape that opens in the tread tread and is recessed inward in the tire radial direction with respect to the tread, and is larger than the maximum width in the direction perpendicular to the tire radial direction. It means that the maximum depth from the tread tread to the inside in the tire radial direction is larger.
In particular, the "pin sipe" preferably has a maximum width of 5 mm or less in the direction perpendicular to the tire radial direction.

As shown in FIGS. 2 and 3A, in the present embodiment, the pin sipe 11 has a circular opening 11a having a diameter of 5 mm, a cylindrical side surface 11b having the same diameter as the opening 11a, and a bottom surface having the same shape as the opening 11a. It has 11c and has a cylindrical shape in which the depth from the opening 11a to the bottom surface 11c facing inward in the tire radial direction is larger than 5 mm.
With such a configuration, the pin sipe 11 has a predetermined volume for forming the air chamber of the Helmholtz type resonator 10, and the area of the opening 11a is larger than the maximum width in the direction perpendicular to the tire radial direction. The maximum depth from the tread tread to the inside in the radial direction of the tire can be made smaller than that of the concave one.

In the present embodiment, the pin sipe 11 has a cylindrical shape having a circular opening 11a, but the maximum depth from the tread surface 2a of the tread 2 to the inside in the tire radial direction is larger than the maximum width in the direction perpendicular to the tire radial direction. If the tire is larger, for example, the side surface 11b has a diameter-expanded portion having a diameter larger than that of the opening 11a, and the shape having the maximum width in the diameter-expanded portion or a triangular prism shape having a triangular opening. The shape of the thing can be changed in various ways.

The narrowing groove 12 is provided on the tread surface 2a of the tread 2. The constriction groove 12 is open to the inner surface of the annular groove 4 at one end and is connected to the pin sipe 11 at the other end. That is, the narrowing groove 12 is a passage for communicating the pin sipe 11 to the inside of the annular groove 4.
The groove width of the narrowed groove 12 is narrower than the maximum width of the pin sipe 11, and the groove depth of the narrowed groove 12 is shallower than the depth of the pin sipe 11. The constriction groove 12 is a portion between the pin sipe 11 and the annular groove 4 that functions as a neck of the Helmholtz type resonator 10, and its volume is sufficiently smaller than the volume of the pin sipe 11.

As shown in FIGS. 2 and 3B, in the present embodiment, the narrowed groove 12 has a groove shape having a rectangular cross section in which the groove depth is larger than the groove width, and the tire width direction and the tire circumferential direction. It extends at an angle with respect to both.
The cross-sectional shape of the narrowed groove 12 can be changed in various ways. Further, the extending direction of the narrowed groove 12 can be variously changed, for example, extending along the tire width direction.

The first sipe 13 is provided on the tread surface 2a of the tread 2 and is connected to the pin sipe 11 at one end. The second sipe 14 is provided on the tread surface 2a of the tread 2 and is connected to the pin sipe 11 at one end.

Here, "sipe" means a groove having a groove width of 1 mm or less.

As shown in FIGS. 2 and 3C, in the present embodiment, the first sipe 13 and the second sipe 14 have a groove shape having a rectangular cross section, each having a groove depth larger than the groove width. It extends at an angle in both the tire width direction and the tire circumferential direction.

In the present embodiment, the narrowed groove 12, the first sipe 13 and the second sipe 14 each have the same cross-sectional shape, and the groove width is 1 mm.

In the Helmholtz type resonator 10 having the above configuration, when the vehicle is traveling, the pin sipe 11 is blocked by the road surface to form an air chamber, and the narrow groove 12 is closed by the road surface to form a narrow passage (neck) connected to the annular groove 4. Will be done.

According to the tire 1 of the present embodiment provided with the Helmholtz type resonator 10 having the above configuration, the Helmholtz type resonator 10 transmits noise due to air column resonance generated between the road surface and the annular groove 4 when the vehicle is running. It can be reduced. Thereby, the quietness of the tire 1 can be improved.
Further, according to the tire 1 of the present embodiment, since the pin sipe 11 is used to form the air chamber of the Helmholtz type resonator 10, the groove is used to form the air chamber of the Helmholtz type resonator 10. It is possible to increase the contact area of the tread 2 provided with the Helmholtz type resonator 10 on the road surface when the vehicle is running, as compared with the case where a groove shape having a shallow groove depth with respect to the length is used. it can.
Further, according to the tire 1 of the present embodiment, since the pin sipe 11 is used to form the air chamber of the Helmholtz type resonator 10, an air chamber having a larger volume than the opening area is secured. Therefore, the Helmholtz type resonator 10 can be provided with an air chamber having a sufficient volume, and the quietness of the tire 1 can be further enhanced.

Further, according to the tire 1 of the present embodiment, the Helmholtz type resonator 10 having the above configuration includes the first sipe 13 and the second sipe 14 connected to the pin sipe 11, so that the range is closed by the road surface 21 of the annular groove 4. It is possible to increase the grip force of the tread 2 on the road surface while reducing the noise caused by the air column resonance generated in.

^{The resonance frequency f of the Helmholtz type resonator 10 having the above configuration is V (cm 3} ) for the volume of the pin sipe 11 (volume of the air chamber formed by the pin sipe 11 being blocked by the road surface) and the cross-sectional area of the stenosis groove 12 (stenosis). The cross-sectional volume of the narrowed passage formed by the groove 12 being blocked by the road surface) is S (cm ² ), and the path length of the narrowed groove 12 from the annular groove 4 to the pin sipe 11 (the narrowed groove 12 is closed by the road surface). When the path length of the narrowed passage is L (cm) and the sound velocity is c, it can be expressed as ^{f = (c / 2π) × (S / VL) 1/2.} The Helmholtz type resonator 10 has a volume V of the pin sipe 11 based on the above equation so that the air column resonance of the resonance frequency f generated between the road surface and the annular groove 4 can be reduced when the vehicle is traveling. , The cross-sectional area S of the constriction groove 12, and the path length L from the opening 12a of the constriction groove 12 to the pin sipe 11 are appropriately set.

In order to correct the additional vibration of air around the outside of the opening of the narrow groove 12 to the annular groove 4, the path length L of the narrow groove 12 from the annular groove 4 to the pin sipe 11 is replaced with the above equation. Therefore, the effective length L'= L + α may be used. The value of α is a constant set according to the cross-sectional area S or the cross-sectional shape of the narrowed groove 12.

As shown in FIG. 2, in the tire 1 of the present embodiment, the first sipe 13 and the constriction groove 12 form the first angle θ1, the second sipe 14 and the constriction groove 12 form the second angle θ2, and the first sipe. The narrowing groove 12, the first sipe 13, and the second sipe 14 are arranged so that at least two of the third angles θ3 formed by the 13 and the second sipe 14 are obtuse angles.

With such a configuration, it is possible to reduce the portion defined at an acute angle at the open end of the pin sipe 11 and prevent the pin sipe 11 from being turned over at the open end of the pin sipe 11 in contact with the road surface when the vehicle is traveling. .. This makes it possible to further increase the contact area of the tread 2 with respect to the road surface when the vehicle is traveling.

In the present embodiment, the first angle θ1 and the second angle θ2 are obtuse angles, respectively, and the third angle θ3 is an acute angle.
With such a configuration, the strength of the open end portion of the pin sipe 11 in the portion between the narrowed groove 12 and the first sipe 13 to the second sipe 14, which is relatively low in strength by being connected to the annular groove 4, is increased. By increasing the height, it is possible to more effectively prevent the pin sipe 11 in contact with the road surface from being turned over when the vehicle is traveling. As a result, the contact area of the tread 2 with respect to the road surface when the vehicle is running can be further increased.

As shown in FIG. 4 as a modification, all of the first angle θ1, the second angle θ2, and the third angle θ3 may be obtuse.
With such a configuration, the open end of the pin sipe 11 is prevented from having an acute-angled portion, and the open end of the pin sipe 11 in contact with the road surface is turned over when the vehicle is running. Can be suppressed more effectively. As a result, the contact area of the tread 2 with respect to the road surface when the vehicle is running can be further increased.

As shown as a modification in FIG. 5, a chamfered portion 20 having a triangular pyramid shape may be provided in the opening 11a of the pin sipe 11. In this case, the opening of the chamfered portion 20 has a triangular shape, and is arranged so that the apex is located on the first sipe 13, the second sipe 14, and the constriction groove 12. The lower apex of the triangular frustum-shaped chamfered portion 20 is located at the axial center of the pin sipe 11.
Since the chamfered portion 20 constitutes the opening of the pin sipe 11, the maximum width of the chamfered portion 20 in the direction perpendicular to the tire radial direction is made smaller than the maximum depth inward from the tread 2a of the tread 2 of the pin sipe 11 in the tire radial direction. To.

With such a configuration, the angle formed by the constriction groove 12, the first sipe 13 to the second sipe 14, and the opening of the pin sipe 11 is made larger than in the case where the chamfered portion 20 is not provided. It is possible to more effectively suppress the occurrence of turning over at the open end portion of the pin sipe 11 in contact with the road surface when the vehicle is traveling. As a result, the contact area of the tread 2 with respect to the road surface when the vehicle is running can be further increased.

The pin sipe 11 can also be formed in a triangular pyramid shape having a triangular opening.
Even with such a configuration, similarly to the above, the angle formed by the constriction groove 12, the first sipe 13 to the second sipe 14, and the opening of the pin sipe 11 is made larger so that the vehicle comes into contact with the road surface when the vehicle is running. It is possible to more effectively suppress the occurrence of turning over at the open end portion of the pin sipe 11.

As shown in FIG. 1, the tire 1 may be configured to include a sub-Helmholtz type resonator 30 on the tread 2. In the present embodiment, the sub-Helmholtz type resonators 30 are provided between the pair of Helmholtz type resonators 10 arranged at intervals in the tire circumferential direction.

The sub-Helmholtz type resonator 30 includes a sub-pinsipe 31 having the same shape as the pin sipe 11 of the Helmholtz type resonator 10, a sub-squeezed groove 32 having the same cross-sectional shape as the narrowed groove 12 of the Helmholtz type resonator 10, and a Helmholtz type resonator. It has a sub-sipe 33 having the same cross-sectional shape as the first sipe 13 of 10.
The sub pin sipe 31 is arranged on the side of the annular groove 4 so as to be offset in the tire width direction from the pin sipe 11, and the length of the sub stenosis groove 32 is shorter than the length of the stenosis groove 12. The sub-sipe 33 is arranged on an extension line of the sub-stenosis groove 32, and its length is longer than the length of the sub-stenosis groove 32.

Also in the sub-Helmholtz type resonator 30 having the above configuration, when the vehicle is running, the sub pin sipe 31 is blocked by the road surface to form an air chamber, and the sub narrow groove 32 is blocked by the road surface to connect to the annular groove 4 (a narrow passage). Neck) is formed. Therefore, the noise caused by the air column resonance generated between the road surface and the annular groove 4 when the vehicle is traveling can also be reduced by the sub-Helmholtz type resonator 30.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments.

For example, in the above-described embodiment, the tire 1 is mounted on a passenger vehicle and used, but the tire is not limited to this, and the tire is, for example, an agricultural vehicle such as a light truck, a bus, a motorcycle, a tractor, or a dump truck. It may be used by being mounted on various automobiles such as construction vehicles, construction vehicles, electric bicycles, and the like.

Further, in the above embodiment, a plurality of Helmholtz type resonators 10 are provided in one annular land portion 3, but the present invention is not limited to this, and for example, a plurality of Helmholtz type resonators 10 are provided in the other annular land portion 3 and the sub-land portion 5. The arrangement of the plurality of Helmholtz-type resonators 10 in the tread 2 can be arbitrarily set, such as the configuration in which the Helmholtz-type resonator 10 is provided.

Further, the annular land portion 3 provided with the Helmholtz type resonator 10 may constitute a shoulder portion of the tread 2.

1: Tire, 2: Tread, 3: Ring land part, 4: Ring groove, 5: Secondary land part, 6: Sub ring groove 6, 10: Helmholtz type resonator, 11: Pinsipe, 11a: Opening, 11b: Side surface , 11c: Bottom surface, 12: Narrow groove, 13: 1st sipe, 14: 2nd sipe, 20: Chamfer, 30: Secondary Helmholtz type resonator, 31: Secondary pin sipe, 32: Secondary narrow groove, θ1: 1st Angle, θ2: 2nd angle, θ3: 3rd angle

Claims

A tire in which an annular groove is provided on the tread surface of an elastic tread, which is divided into a pair of annular land portions extending in the tire circumferential direction over the entire circumference of the tread.
A pin sipe provided on the tread of the tread,
The first sipe and the second sipe, which are provided on the tread of the tread and are connected to the pin sipe, respectively.
A constriction groove provided on the tread surface of the tread, one end of which is connected to the annular groove and the other end of which is connected to the pin sipe to form a Helmholtz type resonator together with the pin sipe, the first sipe and the second sipe. Have,
At least two of the first angle formed by the first sipe and the stenotic groove, the second angle formed by the second sipe and the stenotic groove, and the third angle formed by the first sipe and the second sipe. A tire that is characterized by an obtuse angle.
The tire according to claim 1, wherein the first angle and the second angle are obtuse angles, respectively.
The tire according to claim 2, wherein the third angle is an obtuse angle.
Any one of claims 1 to 3, wherein the opening of the pin sipe is provided with a triangular frustum-shaped chamfer having an apex on the first sipe, on the second sipe, and on the constriction groove, respectively. Tires listed in.