KR20230143644A - Pneumatic tire with improved noise performance - Google Patents

Abstract

The present invention relates to a pneumatic tire in which one or more longitudinal grooves are formed on the tread surface and have side walls facing each other with the floor in between, and are formed in relief at a predetermined height starting from the side wall and extending to the floor. It relates to a pneumatic tire, characterized in that knurling parts composed of one or more protruding mold unit structures are repeatedly arranged in the circumferential direction of the tire. According to the pneumatic tire of the present invention, a knurling part of a special shape is formed in the groove to form a pipe. By reducing the peak of the resonance sound, it provides an excellent effect of improving noise performance by reducing the noise generated when tires are driven.

Description

Pneumatic tires with improved noise performance {PNEUMATIC TIRE WITH IMPROVED NOISE PERFORMANCE}

The present invention relates to a pneumatic tire with improved noise performance. More specifically, it relates to a pneumatic tire with improved noise performance, and more specifically, to a pneumatic tire that reduces noise generated when the tire is driven by forming a specially shaped knurled part in the groove of the tire to reduce the peak of the pipe resonance sound. It's about tires.

As vehicles become quieter, the contribution to vehicle noise caused by tire load rolling increases, and there is a need to reduce tire noise. In particular, since electric vehicles, whose market share is rapidly increasing, do not have engines, the overall noise level is lowered, making low-noise tires more important.

As the 'Tire Noise Performance Labeling System', which is being implemented in the European Union (EU), is scheduled to be introduced in Korea, efforts by the domestic and foreign automobile industries to reduce tire noise are in full swing. Previously, the focus was on reducing noise generated inside the vehicle, such as the engine, but there are increasing cases of applying new low-noise technologies from the early stages of tire product development to minimize noise generated outside the vehicle, such as tires.

Among tire noises, high frequencies, especially tire noise around 1 kHz, are the main cause of extra-vehicle noise and account for most of the noise generated from pneumatic tires. Tire noise around 1 kHz is mainly caused by pipe resonance. The pipe resonance sound is a noise generated by air resonance when a tire is driven, when a pipe is formed between the groove on the tread and the ground and compressed air passes through it. This pipe resonance deteriorates the noise performance of the tire.

Therefore, a technology has been proposed to reduce noise while driving by dispersing the pipe resonance sound generated in the main groove by installing a plurality of lug grooves in the tread block of a pneumatic tire. However, the noise attenuation effect is weak and the tire's There is a need to develop technology to effectively reduce pipe resonance noise occurring within the main groove.

Japanese Patent Publication No. 2012-171479 Domestic registered patent No. 1957640

The present invention is intended to solve the problems of the prior art described above. One purpose of the present invention is to improve the noise performance of the tire by reducing the peak of the pipe resonance sound generated within the groove when the tire is driven.

One aspect of the present invention to achieve the above-described object is,

In a pneumatic tire having one or more longitudinal grooves formed on the tread surface and having side walls facing each other with the floor in between, one protruding in relief at a predetermined height starting from the side wall and extending to the floor. It relates to a pneumatic tire, characterized in that knurling portions composed of the above type unit structure are repeatedly arranged in the circumferential direction of the tire. The knurled part is formed by randomly mixing or alternating knurling parts in the shape of two or more mold unit structures attached to each other at a predetermined interval, so that the pitches of the knurling parts adjacent in the circumferential direction of the tire are the same or different from each other. It can be.

The knurling portion is composed of a bottom knurling portion formed on the bottom of the longitudinal groove and a side wall knurling portion formed on the side wall. The side wall knurling portion extends from the edge of the surface (tread surface) of the tire in the depth direction of the longitudinal groove. And the bottom knurled portion may extend to a point that is approximately 2/3 of the width of the bottom surface of the longitudinal groove.

The height of the knurled portion may be in the range of 0.1 mm to 1 mm.

The curvature (radius) of the contact point between the bottom surface and the side wall surface of the knurled portion is full radius to 2.5 mm.

The knurling portion may be formed so that the protruding height gradually decreases as it moves upward closer to the tread surface of the tire, and the angle (α) applied to the shape of the side portion of the knurling portion can be changed according to the standards of the initial protruding height and groove width.

In the present invention, the thickness of the knurled portion can be formed within the range of 0.4 mm to 1.2 mm.

According to the present invention, the peak of the pipe resonance sound is reduced by forming a specially shaped knurled portion in the longitudinal groove of the tire, thereby effectively reducing the noise generated when the tire is driven.

According to the tire of various embodiments of the present invention, a knurling portion of a predetermined shape is formed across the bottom surface and the side wall surface within the longitudinal groove. This knurled portion changes the groove cross-sectional area of the longitudinal groove in the circumferential direction of the tire, causing a pipe that is generated during grounding. Since the frequency of the resonance sound changes, the noise performance is improved because the constant frequency is not maintained. Additionally, the knurled part on the side wall disturbs the air flow in the longitudinal groove, thereby reducing the pipe resonance sound and further improving the noise performance of the tire. You can do it.

In the present invention, the height of the knurling part is lowered and the knurling part is continuously applied to the bottom and side walls without significantly affecting drainage performance, thereby enlarging the flow contact surface and attenuating noise.

Figure 1 is a schematic perspective view of the tread portion of a pneumatic tire and an enlarged side cross-sectional view of the knurled portion according to an embodiment of the present invention.
Figure 2 is a photograph of a portion of the tread of a pneumatic tire according to an embodiment of the present invention.
Figure 3 is a schematic perspective view of a portion of a groove of a tread of a tire according to various embodiments of the present invention.
Figure 4 is a graph showing the measured peak of the pipe resonance sound band of a physical model of a groove including a knurling portion according to an embodiment of the present invention and a physical model of a groove of a comparative example not including a knurling portion.
Figure 5 is a graph showing the RMS in the pipe resonance band of the actual product of the groove including the knurling portion according to an embodiment of the present invention and the actual product of the groove of the comparative example without the knurling portion.

Hereinafter, the pneumatic tire of the present invention will be described in more detail with reference to the drawings. In order to clearly explain the present invention in the drawings, parts that are not relevant to the description are omitted, and similar parts are given similar reference numerals throughout the specification.

Throughout the specification, when a part is said to be "connected (connected, contacted, combined)" with another part, this means not only "directly connected" but also "indirectly connected" with another member in between. "Includes cases where it is. Additionally, when a part is said to “include” a certain component, this means that it does not exclude other components but may further include other components unless specifically stated to the contrary.

The terms used herein are only used to describe specific embodiments and are not intended to limit the invention. Singular expressions include plural expressions unless the context clearly dictates otherwise.

As used herein, the term "groove" refers to any elongated channel disposed within the tread, including a bottom surface extending in the depth direction within the tread and a pair of side wall surfaces opposing each other with the bottom surface in between. do. “Longitudinal groove” is a groove extending substantially in the longitudinal direction and is used in a similar sense to the main groove.

Figure 1 is a schematic perspective view of the tread of a pneumatic tire according to an embodiment of the present invention and an enlarged cross-sectional view of the knurling portion, and Figure 2 is a plan view of a portion of the tread of a pneumatic tire according to an embodiment of the present invention. Figure 3 is a schematic perspective view of a portion of a groove of a tread of a tire according to various embodiments of the present invention.

Referring to Figures 1 to 3, the pneumatic tire of the present invention applies a knurling portion 200 protruding at an angle to the bottom surface 110 and the side wall surface 120 of the groove to reduce air column resonance sound. It was designed.

The pneumatic tire of the present invention is a pneumatic tire having one or more longitudinal grooves 100 formed on the surface of the tread 10 and having side wall surfaces 120 facing each other with the bottom surface 110 in between, It is characterized in that knurling portions composed of one or more character-shaped unit structures protruding in relief at a predetermined height starting from the side wall surface 120 and extending to the bottom surface 110 are repeatedly arranged in the circumferential direction of the tire. The shape unit structure has a shape similar to a shape in plan view, with the edges on the tread surface being open and the bottom knurling portion formed on the bottom being closed.

The knurled part 200 has a basic unit with a shaped structure, and depending on the number of cuffs 11 of the tread block, two, three or more shaped knurled parts such as a letter or E can be formed in a continuous structure adjacent to each other. You can. Referring to Figure 3, if there is one shaped knurled part, it becomes a small pitch (S-pitch) knurled part 210, and if two shaped knurled parts are attached, it becomes a medium pitch (M-pitch) knurled part 220. If three ,-shaped knurled parts are attached, it becomes a large pitch (L-pitch) knurled part 230. The small pitch knurled portion 210, the medium pitch knurled portion 220, and the large pitch knurled portion 230 are randomly mixed or arranged alternately at predetermined intervals in the circumferential direction of the tire, The pitches of adjacent knurling portions may be the same or different from each other. The pitch interval of the knurling portion 200 may be set to be 10 mm to 30 mm. The number of knurled portions 200 applied to the inner wall surface of the groove may vary depending on the size of blocks and pitches of the tread pattern of the tire.

In the present invention, the knurled part 200 is a structure formed to be connected to the side wall 120 and the bottom surface 110, and is composed of a bottom knurled part 201 and a side wall knurled part 202. As shown in the enlarged view of the circle on the right side of FIG. 1, the side wall knurled portion 202 is formed extending from the top edge 121, that is, the top of the side wall surface 120 of the longitudinal groove 100, in the groove depth direction, The protrusion height may gradually decrease as it moves upward from the groove bottom surface 110. The bottom knurled portion 201 may extend to a point that is approximately 2/3 of the width L1 of the bottom surface 110 of the longitudinal groove 100. That is, the length L2 of the bottom surface knurling portion 201 in the tire width direction is approximately 2/3 of the width L1 of the bottom surface 110 of the longitudinal groove 100. In addition, the protruding height of the groove side wall surface 120 of the knurling portion 200 may be formed to vary and protrude at a constant angle α up to the bottom surface 110. At this time, the angle (α) that determines the variable height of the side wall knurling portion 201 can be designed and changed depending on the groove size.

In the present invention, the protruding height of the knurling portion 200 from the bottom surface 110 or the side wall surface 120 may be in the range of 0.1 mm to 1 mm. If the height exceeds 1.0 mm, a defect may occur in the drainage performance of the tread 10 required for driving on rainy or snowy roads. If the protrusion height of the knurling portion 200 is less than 0.1 mm, the noise attenuation effect is insufficient.

In the present invention, the thickness (d) of the knurled portion 200 may be formed to be 0.4 mm to 1.2 mm.

In the present invention, the curvature (radius) of the connection portion between the bottom knurled portion 201 and the side wall knurled portion 202 of the knurled portion 200 is provided to be between 2.5 mm and a full radius forming a circle. You can.

In the present invention, the protruding height, thickness, and curvature of the knurled portion 200 of the longitudinal groove may be prepared to correspond to the shape of the longitudinal groove 100 within the above range. Additionally, when arranging the knurling portions 200, the position of each unit shape may be changed depending on the tread block and pitch size, and may be arranged so that the gaps are widened rather than spaced apart and connected depending on the arrangement of the knurling portions.

Example

A tire according to an embodiment of the present invention was test manufactured and air column resonance sound attenuation and noise performance were evaluated. 4 and 5 are graphs showing the results of performance tests of pneumatic tires according to the present invention.

In the first experiment, a mock-up was used, and a comparative example model was prepared that reproduced the shape of a conventional tire without a knurled portion in the longitudinal groove. And the pipe resonance sound was measured for the comparative example model and the example model. For this purpose, a Q-source, an air volume exciter, and a microphone for noise measurement were used. Figure 4 is a graph showing the results of comparing the air column resonance sound of the comparative example and the actual model of the tire of the present invention.

The shape of the longitudinal groove of the comparative example (red) in which the knurled part was not formed in the groove and the groove (blue) of the tire in which the knurled part was formed in the longitudinal groove of the present invention were manufactured as a mock-up to compare and evaluate the noise performance. As a result of comparison, as shown in FIG. 4, it was confirmed that the air column resonance peak was reduced in the tire of the present invention, and that the peak was reduced by 0.9 dB and the RMS was reduced by 0.73 dB in the 800 to 12,500 Hz band.

Figure 5 is a graph showing the results of comparing the air column resonance sound of the actual product of the present invention and the actual product of the comparative example. An actual tire embodying the present invention was manufactured and the sound pressure of each tire when driven at 40 to 130 km/h was measured in an anechoic chamber dynamo, and the results are shown graphically in FIG. 5. As shown in Figure 5, the tire of the embodiment of the present invention showed a noise reduction effect in most speed ranges after about 50 kph.

In this way, the peak value of the pipe resonance sound and the RMS value of the pipe resonance sound band generated in the physical model of the tire of the present invention are higher than the peak value of the pipe resonance sound and the RMS value of the pipe resonance sound band generated in the physical model of the groove of the comparative example. It can be confirmed that the noise reduction effect of the tire of the present invention is improved by being formed small.

Although specific embodiments of the present invention have been described in detail above, this is for illustrative purposes only and is not intended to limit the scope of protection of the present invention in any way. A person skilled in the art to which the present invention pertains will understand that the present invention can be easily modified into another specific form without changing its technical idea or essential features. The true scope of protection of the present invention should be determined by the claims described below, and all changes or modified embodiments derived from the claims and their equivalents should be construed as being included in the scope of the present invention.

10: Tread
100: longitudinal groove
110: bottom surface
120: side wall
121: edge
200: Knurling part
201: Bottom knurled part
202: Side wall knurled portion
210: Small pitch knurled part
220: Medium pitch knurled part
230: Large pitch knurled portion

Claims (7)

In a pneumatic tire having one or more longitudinal grooves formed on the tread surface and having side walls facing each other with the floor in between, one protruding in relief at a predetermined height starting from the side wall and extending to the floor. A pneumatic tire characterized in that knurling portions composed of the above type unit structure are repeatedly arranged in the circumferential direction of the tire.
The method of claim 1, wherein the knurling portions are formed in a randomly mixed manner or alternately arranged in a shape in which two or more mold unit structures are spaced apart at a predetermined interval, and the pitch of the knurling portions adjacent to each other in the circumferential direction of the tire is Pneumatic tires characterized in that they are formed to be the same or different from each other.
The method of claim 1, wherein the knurling portion is composed of a bottom knurled portion and a side wall knurled portion connected to each other, and the side wall knurled portion extends in the depth direction of the longitudinal groove at the edge of the tread surface of the tire, and the bottom knurled portion A pneumatic tire characterized in that it extends to a point that is approximately 2/3 of the width of the bottom surface of the longitudinal groove. The pneumatic tire according to claim 1, wherein the protruding height of the knurling portion is 0.1 mm or more and 1 mm or less.
The pneumatic tire according to claim 1, wherein the curvature (radius) of the contact point between the bottom surface of the knurled portion and the side wall surface is between full radius and 2.5 mm.
The pneumatic tire according to claim 1, wherein the protruding height of the knurled portion gradually decreases as it moves from the bottom of the tire to the top near the contact surface.
The pneumatic tire according to claim 1, wherein the thickness (d) of the knurling portion is 0.4 mm to 1.2 mm.

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