KR102501301B1 - Tire and method for manufacturing parting line of tire - Google Patents

Abstract

A tire according to an embodiment of the present invention, a tread extending along the circumferential direction of the tire and having a groove formed thereon; and a plurality of parting lines formed along the surface of the tread in a direction perpendicular to the circumferential direction, the plurality of parting lines being formed in a direction extending from the central axis AX of the tire, and the central axis AX ) Among the central angles CA formed between the plurality of parting lines based on , two central angles have different angles.

Description

Tire and tire parting line manufacturing method {TIRE AND METHOD FOR MANUFACTURING PARTING LINE OF TIRE}

The present invention relates to a tire and a method for manufacturing a tire parting line, and more particularly, to a tire with reduced noise and a method for manufacturing a tire parting line.

Radial tires, which are mainly used for passenger cars, are assembled with an inner liner, carcass cord, and side wall, and then a belt and a cap fly. , Tread is attached to become a semi-finished product. Then, the assembled semi-finished product is inflated with a bladder and molded into a green case. Thereafter, the green case is inserted into a tire mold having a predetermined size and shape, and a curing process is performed by applying heat and pressure to finally complete a radial tire.

In general, a tire mold mold used in a curing process includes a plurality of tread mold segments in which the tread mold is divided into several parts. At this time, a tread mold parting line is formed at a connection portion between each tread mold segment.

The tread mold segments are arranged to form the same central angle around the central axis of the tire, and the tread mold parting lines formed therethrough are also formed at regular intervals to have the same central angle around the central axis of the tire. However, when the tread mold parting lines are arranged at equal intervals, a periodic exciting force is caused by a combination of the parting lines, which may cause vibration of a specific frequency component. When the vibration of a specific frequency component becomes stronger, abnormal noise may occur in the tire.

The present invention is to solve the above problems, and to provide a tire having a structure capable of reducing tire noise and a method for manufacturing a tire parting line.

However, these problems are exemplary, and the problem to be solved by the present invention is not limited thereto.

A tire according to an embodiment of the present invention, a tread extending along the circumferential direction of the tire and having a groove formed thereon; and a plurality of parting lines formed along the surface of the tread in a direction perpendicular to the circumferential direction, the plurality of parting lines being formed in a direction extending from the central axis AX of the tire, and the central axis AX ) Among the central angles CA formed between the plurality of parting lines based on , two central angles have different angles.

In the tire according to an embodiment of the present invention, the central angles CA may be formed within a preset angle range.

In the tire according to an embodiment of the present invention, the groove may include: a first groove that goes around in a circumferential direction of the tire; and a second groove formed in a direction perpendicular to the circumferential direction, and the plurality of parting lines may not overlap with the second groove.

A method for manufacturing a parting line of a tire according to an embodiment of the present invention includes generating a plurality of position samples of a parting line formed on a tire using a random function; generating impulse signals for a plurality of parting lines of the parting line position sample; Selecting a parting line position sample having a frequency having a high dispersion by analyzing dispersion of the converted frequency after fast Fourier transform (FFT) of the impulse signal; and manufacturing tread mold segments such that parting lines are generated at respective positions of the selected parting line position samples, and manufacturing a tire using the tread mold segments.

In the method for manufacturing a parting line of a tire according to an embodiment of the present invention, in the step of generating a plurality of parting line position samples using the random function, the central angle between two adjacent parting lines is formed within a preset angle range. The plurality of parting line position samples may be generated.

In the method for manufacturing a parting line of a tire according to an embodiment of the present invention, the generating of the impulse signal for the parting line position samples may include unit-sized impulses at positions of the parting lines distributed in the circumferential direction of the tire. signal can be generated.

Other aspects, features, and advantages other than those described above will become clear from the detailed description, claims, and drawings for carrying out the invention below.

A method for manufacturing a tire and a tire parting line according to an embodiment of the present invention reduces tire noise and ideally by arranging tread mold parting lines at positions with high dispersion so that central angles between the parting lines can be different. noise can be avoided.

The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims.

1 is a front view showing a tire having a parting line according to an embodiment of the present invention.
FIG. 2 is a partial perspective view seen from the direction A of FIG. 1;
3 is a cross-sectional view taken along line III-III in FIG. 1 .
4 is a comparison diagram showing a parting line according to an embodiment of the present invention along with a parting line divided equally.
5 is a partial view showing how a parting line according to an embodiment of the present invention is formed within a set angle range.
FIG. 6 is a view from the direction A of FIG. 1, showing a state in which a parting line is formed on a tread.
7 is a flowchart of a method for manufacturing a parting line of a tire according to an embodiment of the present invention.
8 is a view showing the arrangement of different tread mold segments reflecting the selected parting line positions.

Since the present invention can apply various transformations and have various embodiments, specific embodiments will be illustrated in the drawings and described in detail in the description of the invention. However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all conversions, equivalents, or substitutes included in the spirit and scope of the present invention. In describing the present invention, even if shown in different embodiments, the same identification numbers are used for the same components.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, and when describing with reference to the drawings, the same or corresponding components are assigned the same reference numerals, and overlapping descriptions thereof will be omitted. .

In the following embodiments, terms such as first and second are used for the purpose of distinguishing one component from another component without limiting meaning.

In the following examples, expressions in the singular number include plural expressions unless the context clearly dictates otherwise.

In the following embodiments, terms such as include or have mean that features or components described in the specification exist, and do not preclude the possibility that one or more other features or components may be added.

In the drawings, the size of components may be exaggerated or reduced for convenience of explanation. For example, since the size and thickness of each component shown in the drawings are arbitrarily shown for convenience of description, the present invention is not necessarily limited to those shown.

In the following embodiments, the x-axis, y-axis, and z-axis are not limited to the three axes of the Cartesian coordinate system, and may be interpreted in a broad sense including these. For example, the x-axis, y-axis, and z-axis may be orthogonal to each other, but may refer to different directions that are not orthogonal to each other.

When an embodiment is otherwise implementable, a specific process sequence may be performed differently from the described sequence. For example, two processes described in succession may be performed substantially simultaneously, or may be performed in an order reverse to the order described.

Terms used in this application are only used to describe specific embodiments, and are not intended to limit the present invention. In this application, the terms "include" or "have" are intended to designate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, but one or more other features It should be understood that the presence or addition of numbers, steps, operations, components, parts, or combinations thereof is not precluded.

For reference, unless specifically limited in the present specification, the driving direction may correspond to the X-axis direction, the width direction to the Y-axis direction, and the height direction to the Z-axis direction, respectively.

Hereinafter, a tire having a parting line according to an embodiment of the present invention will be described with reference to FIGS. 1 to 4 .

1 is a front view showing a tire having a parting line according to an embodiment of the present invention. FIG. 2 is a partial perspective view seen from the direction A of FIG. 1; 3 is a cross-sectional view taken along line III-III in FIG. 1; 4 is a comparison diagram showing a parting line according to an embodiment of the present invention along with a parting line divided equally.

1 to 4, the tire 100 according to an embodiment of the present invention extends along the circumferential direction of the tire 100 and has a tread 110 having a groove 115 formed thereon, perpendicular to the circumferential direction. and a plurality of parting lines PL formed along the surface of the tread 110 in the in direction.

The tire 100 is a pneumatic tire and may include a tread 110, a sidewall 120 extending from both sides of the tread 110, and a bead 130 disposed at an end of the sidewall 120. there is.

In addition, the tire 100 may include a body ply 140 and a belt layer 150 located below the tread 110, and a cap ply 160 may be further included on the upper portion of the belt layer 150. there is. In addition, the tire 100 may include an inner liner 170 positioned inside the tread 110 and the pair of sidewalls 120 to maintain the internal air pressure of the tire 100 .

Referring to FIG. 1 , the tire 100 may have a shape extending in a circumferential direction RT around a central axis AX. In addition, a wheel (not shown) may be coupled to the inner side of the tire 100 based on the radial direction r from the central axis AX.

The tread 110 may include a region facing the road surface during driving after the tire 100 is mounted on the vehicle. For example, the tread 110 may include a region in contact with the road surface during driving of the vehicle. The tread 110 is made of a thick rubber layer and transmits driving lock and braking force of the vehicle to the ground.

The tread 110 may have one or more patterns, and a plurality of grooves 115 may be formed adjacent to these patterns. The groove 115 may have a shape extending in at least the first direction. In addition, the groove 115 may also include a region having a shape extending in a direction crossing the first direction.

The number and shape of the grooves 115 may be variously determined according to the driving characteristics and usage of the tire 100 .

The groove 115 may be formed adjacent to the pattern of the tread 110 . For example, the groove 115 may form a boundary of one area of the tread 110 in a form in which one area of the tread 110 is removed.

The number and shape of the grooves 115 may be variously determined according to driving characteristics and uses of the tire 100 . The groove 115 may include a plurality of grooves.

The tread 110 may have a tread block TB partitioned by a plurality of grooves 115 . The tread block TB is a part that comes into contact with the road surface during driving of the vehicle, and is partitioned by a first groove running in the circumferential direction of the tire 100 and a second groove formed in a direction perpendicular to the circumferential direction. can

On the surface of the tread block TB, tread patterns for steering stability, traction, and braking properties, and blocks partitioned by the tread patterns may be positioned. The tread patterns may include a plurality of grooves 115 for back pain when driving on a road surface, and sipes 116 for improving traction and braking power. The sipe is formed in the tread block TB and may be a groove having a smaller size than the groove. Sipes can increase the driving force and braking force of the tire 100 by absorbing moisture and breaking the water film when driving on a wet road.

Sidewalls 120 extend from both sides of the tread 110 to form the sidewalls of the tire 100 . The sidewall 120 is made of the same or different material as the tread 110 and protects the bead 130 and the body ply 140, which will be described later. In one embodiment, one end of the sidewall 120 may extend from one side of the tread 110 and the other end may contact the tire rim.

The bead 130 is disposed at the lower end of the sidewall 120 and is formed in the form of a square or hexagonal wire bundle in which rubber is coated on a steel wire, so that the tire 100 and the tire rim can help with the combination of In one embodiment, the bead 130 is arranged to be wrapped by the body ply 140, so that the tire 100 can be seated and fixed to the tire rim.

The bead 130 may include a bead core 131 and a bead filler 132 . The bead core 131 is disposed below the bead filler 132 and may be formed by twisting a plurality of rubber-coated steel bead cords (wires). The bead filler 132 may be disposed extending from the bead core 131 in the sidewall direction. The bead filler 132 is a rubber filler attached to one side of the bead core 131 and serves to reinforce the bead core 131 . In another embodiment, a plurality of bead fillers 132 may have different physical properties. Bead 130 may have a plurality of insertion grooves (not shown). The insertion groove is inserted into the mounting protrusion of the rim, so that the tire can be mounted on the rim.

The body ply 140 forms the skeleton of the tire 100 and is configured to increase durability of the tire 100, and may be formed by topping a rubber material on a fiber cord. The body ply 140 can absorb loads and shocks received by the tire 100 and maintain the air pressure of the tire 100 at a certain level. In one embodiment, the body ply 140 is turned up from the inner surface (In) toward the outer surface (Out) of the tire 100 and may be disposed to cover at least a portion of the bead 130. .

The body ply 140 may be formed by overlapping a plurality of cord papers made of high-strength fiber organic materials such as steel, polyester, or rayon, and then coating them with rubber and rolling them. Specifically, the body ply 140 may include at least one rubber component selected from the group consisting of synthetic rubber and natural rubber, and may include at least one tire cord. Various natural fibers or rayon, nylon, polyester, and Kevlar may be used as the tire cord, and a steel cord formed by twisting a plurality of thin wires may also be used.

The inner liner 170 may be disposed on the inner surface In of the body ply 140 . The inner liner 170 may prevent leakage of air from the tire 100 and maintain air pressure in the tire 100 . The inner liner 170 may be formed of a rubber layer having excellent sealing properties. For example, the inner liner 170 may be made of high-density butyl rubber or the like.

The inner liner 170 may be disposed inside the body ply 140 and extend to the bead 130 . The inner liner 170 may contact one surface of the body ply 140, and both ends may contact the bead 130.

Belt layer 150 may be disposed between tread 110 and body ply 140 . The belt layer 150 can improve grounding characteristics and driving stability by mitigating the shock received by the tire 100 from the road surface when the vehicle C on which the tire 100 is mounted is driven, and by extending the contact surface of the tread 110. there is. The belt layer 150 may be formed by rolling by coating a plurality of belt cords made of steel or organic fibers with rubber. Belt layer 150 may be provided with a plurality of layers. For example, as shown in FIG. 3 , the first belt layer 151 disposed on the upper surface of the inner liner 170 and the second belt layer 152 disposed on the upper surface of the first belt layer 151 can be provided.

A cap ply 160 may be disposed between the belt layer 150 and the tread 110 . The cap ply 160 is formed of special cord paper to minimize the movement of the belt layer 150 during driving of the vehicle and to prevent separation of the belt layer 150 during high-speed driving. The cap ply 160 may include a polyester synthetic fiber. The cap ply 160 is supported by the belt layer 150 and the body ply 140, thereby minimizing the movement of the belt layer 150 during driving.

Referring to FIG. 1 , the plurality of parting lines PL are formed in a direction extending from the central axis AX of the tire, and two adjacent parting lines among the plurality of parting lines PL based on the central axis AX The central angles CA between them are formed at different angles.

The plurality of parting lines PL is irregularly arranged so that central angles CA between two adjacent parting lines among the plurality of parting lines PL are formed at different angles, according to the arrangement of the parting lines. Noise generated from tires can be reduced.

In addition to joints of various semi-finished products, there are parting lines of tread molds in tires, and a combination of semi-finished joints and tread mold parting lines causes periodic excitation force to cause vibration of a specific frequency component. At this time, a cavity peak whose amplitude rapidly increases at a specific location according to the vibration of a specific frequency component may occur. When the amplitude rapidly increases at a specific location, abnormal noise may occur at that location.

As one embodiment, the tire 100 may be formed such that eight parting lines PL1 , PL2 , PL3 , PL4 , PL5 , PL6 , PL7 , and PL8 are arranged as shown in FIGS. 1 and 4 . Also, 8 central angles CA1 , CA2 , CA3 , CA4 , CA5 , CA6 , CA7 , CA8 , which are not equally divided, may be formed between the 8 parting lines. When the eight parting lines are equally divided, a cavity peak whose amplitude rapidly increases may occur at a specific location according to the vibration of a specific frequency component, and abnormal noise according to the cavity peak may occur through the tire.

Therefore, by arranging a plurality of parting lines PL in irregular and unequal divisions as in one embodiment of the present invention, the frequency components according to the parting lines are distributed and the amplitude of the cavity peak generated in a specific component among the frequency components By reducing the size, abnormal noise generated from the tire can be reduced.

According to the present embodiment, in order to arrange the plurality of parting lines PL in irregular and unequal divisions, the central angle CA between two adjacent parting lines among the plurality of parting lines PL based on the central axis AX. ) may have different angles from each other, and the plurality of parting lines PL may be arranged. Abnormal noise that may occur in a tire may be reduced through the arrangement of the parting lines PL arranged in non-equal divisions.

Hereinafter, the angular range of the central angle CA according to an embodiment of the present invention will be described with reference to FIG. 5 .

5 is a partial view showing how a parting line according to an embodiment of the present invention is formed within a set angle range. For a description of components not shown in FIG. 5 , reference may be made to those shown in FIGS. 1 to 4 .

Referring to FIG. 5 , central angles CA between the plurality of parting lines PL may be formed within a set angle range.

Even if the plurality of parting lines PL are irregularly arranged, the parting lines PL may be formed to have a central angle CA outside a specific range, such as when the parting lines PL are arranged to lean towards a part of a tire. In this case, the convenience of driving and the safety of adjustment may be deteriorated.

Accordingly, according to the present embodiment, central angles CA between a plurality of parting lines PL arranged irregularly and unequally are formed within a set angle range, thereby forming central angles CA that do not deviate from the set range. A plurality of parting lines PL may be arranged. According to this embodiment, eight parting lines PL are formed, and central angles CA of each parting line may be set within a range of ±a degrees based on 45 degrees. Degree a can be formed into four degrees.

As an experimental example, in a tire composed of 8 parting lines, when the center angles (CAs) were set to 2 degrees and the a degree was set to 4 degrees based on 45 degrees, irregularly The difference in amplitude at the cavity peak according to the arranged parting line was compared.

CA1 CA2 CA3 CA4 CA5 CA6 CA7 CA8 45±2 degrees 46.18 45.16 44.24 45.73 43.74 45.78 43.36 45.81 45±4 degrees 45.12 48.62 41.06 44.72 45 48.96 45.11 41.41

As a result of comparing the amplitude at the cavity peak and cavity peak of each tire formed with the parting lines constituting the central angles (CA) according to the table above, the cavity peak amplitude at 45 ± 4 degrees is higher than the cavity peak amplitude at 45 ± 2 degrees. A decrease of 12% can be seen. As the amplitude at the cavity peak decreases, noise generated from the tire can be reduced.

Hereinafter, a plurality of parting lines designed to avoid grooves according to an embodiment of the present invention will be described with reference to FIG. 6 .

FIG. 6 is a view from the direction A of FIGS. 1 and 2 , showing a state in which a parting line is formed on a tread. For a description of components not shown in FIG. 6 , reference may be made to those shown in FIGS. 1 to 4 .

Referring to FIG. 6 , the parting line PL according to an embodiment of the present invention may be formed so as not to overlap the second groove 115b.

The groove 115 may include a first groove 115a traveling along the circumferential direction of the tire 100 and a second groove 115b formed in a direction perpendicular to the circumferential direction. The sipe 116 is formed on the tread block and may be formed as a groove having a smaller size than the groove 115 .

When the plurality of parting lines PL are formed in a direction perpendicular to the circumferential direction and overlap the second groove 115b formed in a direction parallel to the plurality of parting lines PL, the second A step in the groove (115b) can reduce the drainage and drivability of the tire. By designing the plurality of parting lines (PL) so that they do not overlap with the second groove (115b), the risk of step difference during the curing process is prevented in advance can do.

Hereinafter, a method for manufacturing a parting line of a tire according to an embodiment of the present invention will be described with reference to FIGS. 7 and 8 .

7 is a flowchart of a method for manufacturing a parting line of a tire according to an embodiment of the present invention. 8 is a view showing the arrangement of different tread mold segments reflecting the selected parting line positions. Descriptions of configurations not shown in FIGS. 7 and 8 may refer to those shown in FIGS. 1 to 4 .

7 and 8 , a method for manufacturing a parting line of a tire according to an embodiment of the present invention includes generating a plurality of position samples of the parting line PL formed on the tire 100 using a random function ( S100), generating impulse signals for a plurality of parting lines (PL) of the parting line position sample (S200), analyzing the dispersion of the transformed frequency after Fast Fourier Transformation (FFT) on the impulse signal (S300) selecting a parting line location sample having a high frequency dispersion (S400) and producing tread mold segments 101 such that parting lines are generated at respective positions of the selected parting line location sample, A tire is manufactured using the tread mold segments 101 (S500).

As a process of manufacturing a plurality of parting lines PL, a step (S100) of generating location samples of the parting line using a random function is first performed. In one embodiment, 10000 parting line position samples may be generated using a random function. In addition, as an embodiment, when formed with 8 parting lines as shown in FIGS. 1 and 4 , 10000 parting line position samples in which 8 parting lines are formed may be generated using a random function.

In this case, the method may further include generating a plurality of parting line position samples such that a central angle CA between two adjacent parting lines is formed within a preset angle range. Therefore, when a parting line position sample is generated using a random function, the parting line position is determined by specifying conditions in the random function such that central angles (CAs) between a plurality of parting lines of the parting line position sample are formed within a preset angle range. samples can be created.

After generating the parting line position samples, a step of generating impulse signals for a plurality of parting lines of the parting line position samples (S200) is performed. In this step, unit-sized impulse signals may be generated at locations of each parting line distributed in the circumferential direction of the tire 100 .

That is, the impulse signal may be generated by applying a unit step function having a unit size of 1 to each of the portions where a plurality of parting lines formed along the circumferential direction of the tire go around the circumference of the tire.

After the impulse signal is generated, fast Fourier transform (FFT, Fast, Fourier Transformation) may be performed on the generated circumferential impulse signal. After performing the fast Fourier transform, a step of analyzing the variance of the transformed frequency (S300) is performed. Through the step of analyzing the degree of dispersion, a step of selecting a parting line location sample having the highest degree of dispersion among the respective parting line samples (S400) may be performed.

As an example, when eight parting lines are arranged as shown in FIGS. 1 and 4 , a cavity peak may occur. In this case, in the case of a parting line position sample with high dispersion, the amplitude of the cavity peak in the frequency waveform is relatively reduced and the frequency waveform is evenly distributed, which can increase the dispersion. The higher the dispersion in the frequency waveform, the lower the amplitude at the cavity peak, reducing the size of vibration at a specific frequency, so noise generated from the tire can be reduced.

In another embodiment, when selecting the optimal parting line position sample through the degree of dispersion, the parting line position sample may be selected by additionally considering the position of the parting line and the overlap mass of the molding joint disposed inside the tire. .

That is, in the step of generating the impulse signal, a forming joint component overlapped with the position of the parting line is additionally generated as an impulse signal, and the impulse signal according to the position of the parting line and the forming joint component are frequency-converted together to obtain a degree of dispersion. By checking the position sample of the parting line can be selected. In this way, when the degree of dispersion is confirmed by additionally considering the molded joint component, the frequency dispersion can be more precisely measured, and the noise reduction effect of the tire can be further improved accordingly.

After selecting the parting line position sample having the highest degree of dispersion, tread mold segments 101 reflecting the parting line position of each of the selected parting line position samples that are not equally divided are manufactured, and the tread mold segment 101 and manufacturing a tire so that the plurality of parting lines PL are arranged in an irregular and non-equally divided manner using (S500).

By manufacturing the tread mold segment 101 in consideration of the position of the parting line at which noise can be reduced and manufacturing the tire through the tread mold segment 101, noise of the tire can be reduced and a tire of higher quality can be provided.

As such, the present invention has been described with reference to the embodiments shown in the drawings, but this is only an example. Those skilled in the art can fully understand that various modifications and equivalent other embodiments are possible from the embodiments. Therefore, the true technical protection scope of the present invention should be determined based on the appended claims.

Specific technical details described in the embodiments are examples, and do not limit the technical scope of the embodiments. In order to briefly and clearly describe the description of the invention, descriptions of conventional general techniques and configurations may be omitted. In addition, the connection of lines or connection members between the components shown in the drawing is an example of functional connection and / or physical or circuit connection, which can be replaced in an actual device or additional various functional connections, physical connections, or circuit connections. In addition, if there is no specific reference such as "essential" or "important", it may not necessarily be a component necessary for the application of the present invention.

“Above” or similar designations described in the description and claims of the invention may refer to both singular and plural, unless otherwise specifically limited. In addition, when a range is described in an embodiment, it includes an invention in which individual values belonging to the range are applied (unless there is no description to the contrary), and each individual value constituting the range is described in the description of the invention. same. In addition, if there is no clear description or description of the order of steps constituting the method according to the embodiment, the steps may be performed in an appropriate order. Embodiments are not necessarily limited according to the order of description of the steps. The use of all examples or exemplary terms (eg, etc.) in the embodiments is simply to describe the embodiments in detail, and unless limited by the claims, the examples or exemplary terms limit the scope of the embodiments. It is not. In addition, those skilled in the art will appreciate that various modifications, combinations and changes may be made according to design conditions and factors within the scope of the appended claims or equivalents thereof.

100: tire
AX: central axis
CA: central angle
PL: parting line

Claims (6)

delete delete delete generating a plurality of position samples of parting lines formed on the tire using a random function;
generating impulse signals for a plurality of parting lines of the parting line position sample;
Selecting a parting line position sample having a frequency having the highest dispersion by analyzing dispersion degrees of the transformed frequency after fast Fourier transform (FFT) of the impulse signal; and
Manufacturing tread mold segments so that parting lines are created at respective positions of the selected parting line position samples, and manufacturing a tire using the tread mold segments,
In the step of generating a plurality of parting line position samples using the random function,
A method for manufacturing a parting line of a tire, wherein the plurality of parting line position samples are generated such that a central angle between two adjacent parting lines is formed within a preset angle range. delete According to claim 4,
Generating an impulse signal for the parting line position samples,
A method of manufacturing a parting line of a tire such that an impulse signal having a unit size is generated at a position of each parting line distributed in a circumferential direction of the tire.

Images