KR20230017510A - Pneumatic tire having a raindrop-shaped groove structure - Google Patents

Abstract

The present invention relates to a pneumatic tire having a raindrop-shaped groove structure. More specifically, the pneumatic tire having a raindrop-shaped groove structure formed to expand the width of a groove from the outside to the inside of a tread. According to one embodiment of the present invention, in a tire tread structure having a groove recessed in a circumferential direction, the groove comprises: a sub-groove extended from a surface of the tread in a radial direction; and a cavity extended from one end of the sub-groove and having a predetermined space therein.

Description

Pneumatic tire having a raindrop-shaped groove structure}

The present invention relates to a pneumatic tire having a raindrop-shaped groove structure, and more particularly, to a pneumatic tire having a raindrop-shaped groove structure in which the width of the groove extends from the outside of the tread toward the inside.

Unless otherwise indicated herein, material described in this section is not prior art to the claims in this application, and inclusion in this section is not an admission that it is prior art.

In the case of not only general pneumatic tires but also heavy-duty pneumatic tires used for buses and trucks, an internal space for injecting air is formed, and the shoulder portion and sidewall are formed on both sides along the width direction of the tire centered on the tread portion. and a bead portion. Among the components of such a tire, the tread portion corresponds to a rubber layer composed of grooves, blocks, and sipes, and as the only part of the tire that directly contacts the ground, it serves to support the load of the vehicle body and continuously receives the load of the vehicle body. It must be strong in friction performance, drainage performance, noise performance, and fatigue resistance, and must be able to withstand external shocks sufficiently.

Here, the groove formed in the tread corresponds to a groove long dug along the circumferential direction of the tread, which is the running direction, and is designed as a pattern to increase drainage for safe braking on a rainy road. Here, the wider the width of the groove, the better the driving performance on the wet road, but if it is excessively wide, the braking force and cornering performance are weakened. and Sipe's optimized design design is continuously being made.

The tread part in contact with the ground receives forces in the circumferential and lateral directions due to repetitive rotation and steering during vehicle driving. A loss occurs and the rolling resistance performance decreases, but the braking performance can be maintained due to the existence of the groove. However, in the later stages of wear, braking performance on wet roads deteriorates due to the absence of residual grooves and reduced tread weight, and rolling resistance performance increases compared to the early stages of wear. Since rolling resistance and braking performance on a wet road have a trade off relationship, a raindrop-shaped groove structure is needed to overcome this performance difference.

In contrast, in Korean Patent Registration No. 10-2006-0105853, "at least one

discloses a tread element having a sipe that transitions from a constant width sipe having a three-dimensional appearance at at least a portion of the radially outer portion of the sipe to a wider groove based on the tread shape. Here, the radius The width (Wi) of the inner sipe in the direction is at least 2.5 times greater than the width (Wo) of the outer sipe in the radial direction. When the width (Wi) is applied, the width for drainage performance is too narrow and the groove The depth (Do) is quite low, so there is a problem that it is difficult to secure the desired braking performance at the later stage of wear.

1. Korean Patent Registration No. 10-1289574 (published on July 24, 2013)

An object of the present invention is to provide a tire tread structure with excellent braking performance and drainage performance by appropriately setting the width, length, and angle within the groove in a raindrop-shaped groove structure in order to supplement wet road braking performance in the latter half of wear.

In addition, it is not limited to the technical problems as described above, and it is obvious that other technical problems may be derived from the following description.

In the tire tread structure including a groove drawn in along a circumferential direction according to an embodiment of the present invention, the groove is formed extending from a subgroove extending radially from the tread surface and one end of the subgroove, , characterized in that it includes a cavity forming a predetermined space therein.

According to a preferred feature of the present invention, the sub-groove is characterized in that the width of the sub-groove expands toward the radial direction, so that the entire groove is formed in a raindrop shape.

According to a preferred feature of the present invention, the sub-groove includes a first sub-groove extending from the upper right corner of the cavity along the circumferential direction of the tire, and a second sub-groove extending from the upper left corner of the cavity along the circumferential direction of the tire. The second sub-groove and a third sub-groove extending obliquely in a circumferential direction so as to connect the first sub-groove and the second sub-groove to each other are further included.

According to a preferred feature of the present invention, the angle (Ai) formed with the upper part of the cavity based on the central axis of the sub-groove is characterized in that it consists of 30 to 65 °.

According to a preferred feature of the present invention, WRi/WRo, which is the ratio of the width (WRi) of the cavity to the width (WRo) of the subgroove, is characterized in that it consists of 12 to 28.

According to a preferred feature of the present invention, Di/Do, which is the ratio of the length Di of the cavity to the total length Do of the groove, is characterized in that it consists of 0.4 to 0.8.

According to the embodiment of the present invention, by having a raindrop shape in which the width of the groove expands in the radial direction on the tread surface, there is an advantage in that drainage performance is increased and wet road braking performance can be improved by removing aquaplaning.

In addition, according to the embodiment of the present invention, additional braking performance can be improved by presenting an optimal ratio for the width and length in the groove, and the tire can be easily taken out of the mold by limiting the upper angle of the cavity.

The effects of the present invention are not limited to the above effects, and should be understood to include all effects that can be inferred from the detailed description of the present invention or the configuration of the invention described in the claims.

1 is a perspective view of a tire tread structure according to an embodiment of the present invention;
2 is a view showing a groove shape including a sub-groove and a cavity in a tire tread structure according to an embodiment of the present invention.
3 is a cross-sectional view of a tire tread structure according to an embodiment of the present invention.
4 is a plan view of a tire tread structure according to an embodiment of the present invention;
Figure 5 is a cross-sectional view of sections AA to CC of Figure 4;

Hereinafter, with reference to the accompanying drawings, a look at the configuration, operation, and effect of the tire tread structure according to the preferred embodiment. For reference, in the drawings below, each component is omitted or schematically illustrated for convenience and clarity, and the size of each component does not reflect the actual size. In addition, like reference numerals refer to like components throughout the specification, and reference numerals for like components in individual drawings will be omitted.

In the tire tread structure including a groove 10 formed along a circumferential direction according to an embodiment of the present invention, the groove 10 includes a sub-groove 11 extending in a radial direction from the tread surface; It is characterized in that it includes a cavity 12 extending from one end of the sub-groove 11 and forming a predetermined space therein.

The groove 10 may have a structure in which grooves are formed along the circumferential direction of the tread, and the groove 10 discharges water introduced between the tire and the road surface during driving on a rainy road to prevent aquaplaning from occurring, It is important to enhance driving performance by increasing traction. In order to optimize the tread structure including the groove 10, the groove 10 disclosed in the present invention includes a sub-groove 11 extending radially from the tread surface and a cavity 12 in which a predetermined space is formed. It can be done. The sub-groove 11 may extend from the outer surface of the tread toward the inside with a predetermined width, may extend while maintaining a constant width, or may have a structure in which the width extends downward.

Here, the narrower the width of the sub-groove 11 is, the narrower the gap between the ribs is, so it is possible to secure the maximum rib rigidity. It is desirable to increase the strain energy and reduce the strain energy loss.

In addition, the sub-groove 11 may further include a cavity 12 extending from one end extending downward while forming a predetermined space. As shown in FIG. 1 or 2, the cavity 12 extends with a larger width than the sub-groove 11, and by forming a predetermined space therein, drainage performance can be improved. The cross section of the cavity 12 may be formed in an octagonal shape as shown in FIG. 2, but is not limited thereto, and may be formed in various shapes for forming an inner space such as a square or a hexagon, and in particular, the subgroove 11 It may be formed in a raindrop shape in order to form an upper inclination angle of the cavity 12 extending from.

According to a preferred feature of the present invention, the width of the sub-groove 11 increases toward the radial direction, so that the entire groove 10 is formed in a raindrop shape.

The sub-groove 11 may be extended while maintaining a constant width and connected to the cavity 12, but may have a structure in which the width expands from the tread surface toward the cavity 12 and may be formed in a kind of raindrop shape. Through the groove 10 formed in this way, it is possible to reduce the loss of braking force on a wet road even in the late stage of wear.

According to a preferred feature of the present invention, the sub-groove 11 includes a first sub-groove 111 extending along the circumferential direction of the tire from the upper right corner of the cavity 12, and the left side of the cavity 12. A second sub-groove 113 extending from the upper end along the circumferential direction of the tire and a third sub-groove 113 extending obliquely in the circumferential direction to connect the first sub-groove 111 and the second sub-groove 113 to each other. It is characterized in that it further comprises a groove (115).

The sub groove 11 can be formed to extend in three ways along the circumferential direction, the first sub groove 111 extending from the upper right corner to the upper part around the cavity 12, and the first sub groove 111 extending to the upper left corner. The second sub groove 113 and the third sub groove 115 interconnecting the first sub groove 111 and the second sub groove 113 may have a structure in which they are connected to each other. Conventionally, in the case of grooves extending in a straight line along the circumferential direction of the tire, the stiffness of the rib in the lateral direction is weakened, and thus the rolling resistance performance is reduced.

To overcome this, the first sub-groove 111 extending to the upper right side with respect to the central axis of the cavity 12 is formed extending a predetermined length along the circumferential direction, and then tilted in the upper left direction of the cavity 12. The third sub-groove 115 is formed extending, and the second sub-groove 113 extending from the upper left corner of the cavity 12 is connected to the end of the third sub-groove 115 and arranged in a kind of zigzag manner. can The first sub-groove 111 to the third sub-groove 115 are repeatedly formed along the circumferential direction of the tire as a set so that the cross section viewed from the top has a repeatedly connected trapezoidal shape, thereby securing transverse rib stiffness. It has the advantage of being able to improve the rolling resistance performance.

In addition, referring to the drawings shown in FIGS. 4 and 5, it is preferable to form the width of the third sub groove 115 larger than the width of the first sub groove 111 and the second sub groove 113. desirable. For example, in FIG. 4, parts SEC.A-A correspond to the first sub-groove 111, parts SEC.B-B correspond to the third sub-groove 115, and parts SEC.C-C correspond to the second sub-groove 113. , the width of the third sub-groove 115 may be formed to be relatively large compared to the widths of the first sub-groove 111 and the second sub-groove 113 . This is a groove for checking the wear pattern of the tire, and is important in that it can prevent accidents that may occur by frequently checking the tire replacement cycle.

According to a preferred feature of the present invention, WRi/WRo, which is the ratio of the width (WRi) of the cavity to the width (WRo) of the subgroove, is characterized in that it consists of 12 to 28.

As shown in FIG. 3, when the width of the sub-groove 11 in the raindrop-shaped groove 10 is defined as WRo and the width of the cavity 12 is defined as WRi, the sub-groove 11 and the cavity ( 12), the width ratio WRi/WRo is preferably between 12 and 28.

The narrower the width of the WRo, the better the RR improvement, and by applying the minimum thickness that can be manufactured (in the following experiment, WRo was applied as 0.5 mm), interference between tread blocks is increased to reduce strain energy loss. In addition, the cavity 12 needs to increase the drainage performance to improve the braking force on the wet road. In the early stage of tire wear, the wet road braking performance is high and the rolling resistance performance is low, but at the later stage of wear, the rolling resistance performance is high and the wet road performance is low. Braking performance on the road surface is reduced.

[Table 1] below shows the wet road braking performance in the latter half of wear when the width (WRi) of the cavity 12 is applied differently while the width (WRo) of the subgroove 11 is kept constant. The higher the value, the better the performance.

Comparative Example 1 Comparative Example 2 Comparative Example 3 Experimental example 1 Experimental Example 2 Experimental Example 3 Experimental Example 4 Experimental Example 5 Comparative Example 4 Comparative Example 5 Comparative Example 6 WRi 1.25 2 4 6 8 10 12 14 16 18 20 WRo 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Wri/WRo 2.5 4 8 12 16 20 24 28 32 36 40 Wet road braking performance 100% 100% 100% 105% 106% 106% 107% 107% 98% 97% 96%

As shown in [Table 1], in Comparative Examples 1 to 3, the wet road braking performance evaluation result when WRi / WRo was 2.5 to 8 was maintained at 100%, Comparative Examples 4 to Comparative In Example 6, when the ratio of WRi / WRo was 32 to 40, the stiffness of the tread block was weakened and the grip force with the ground decreased, resulting in a decrease in braking performance. Able to know. In addition, in Experimental Examples 1 to 5 when the width of the cavity (WRi) was applied differently from 6 to 14 while the width (WRo) of the sub-groove was maintained at 0.5 mm, the water film phenomenon was blocked due to the improvement of drainage performance, so that sequential As the braking performance improved, it can be seen that the wet road braking performance greatly improved to 105-107%.

According to a preferred feature of the present invention, the angle Ai formed with the upper portion of the cavity 12 based on the central axis of the sub-groove 11 is characterized in that it consists of 30 to 65 °.

In the drawing shown in FIG. 3, the angle (Ai) formed between the central axis of the sub-groove 11 and the upper surface of the cavity 12 is preferably made of 30 to 65 °, which means that the cavity ( This is to prevent the strain energy generated in 12).

[Table 2] below shows the evaluation results of strain energy according to the angle Ai formed between the central axis of the sub-groove 11 and the upper surface of the cavity 12. The smaller the strain energy, the better the value. In Comparative Example 7 where the angle Ai is 15 °, the cavity shape is disadvantageous, and the strain energy is greatly increased (105%) in the left part where the upper and lower ends of the cavity 12 come into contact. It was confirmed that, compared to Comparative Example 8, which is 90 °, an increase in strain energy (108%) at the top of the cavity 12 was shown, as in Experimental Examples 6 to 8, the angle Ai was 30 ° to 65 ° When limited to , it can be seen that the strain energy is slightly reduced within the angle range, while the strain energy is 100 to 101%.

Comparative Example 7 Experimental Example 6 Experimental Example 7 Experimental Example 8 Comparative Example 8 Ai 15 30 45 65 90 Strain Energy 105% 100% 101% 101% 108%

According to a preferred feature of the present invention, Di / Do, which is the ratio of the length Di of the cavity 12 to the total length Do of the groove 10, is characterized in that it consists of 0.4 to 0.8.

[Table 3] below shows evaluation results of wet road braking performance according to the ratio of the vertical length Di of the cavity 12 to the total length Do of the groove 10.

Comparative Example 9 Experimental Example 9 Experimental Example 10 Experimental Example 11 Comparative Example 10 Di 2 4 6 8 10 Do 10 10 10 10 10 Di/Do 0.2 0.4 0.6 0.8 1.0 Wet road braking performance 100% 104% 105% 106% 99%

As shown in [Table 3], when the Di/Do ratio in Comparative Example 9 or Comparative Example 10 is 0.2, there is a problem that the drainage performance decreases and the braking performance in the latter half of wear decreases, and the ratio exceeds 1.0. There is a problem in that rotational resistance at the beginning of wear is reduced due to interference between tread blocks and a decrease in rigidity. In contrast, when the ratio of Di / Do is 0.4 to 0.8, it can be seen that the wet road braking performance has an excellent value of 104 to 106%.

Although preferred embodiments of the present invention have been described with reference to the accompanying drawings, the embodiments described in this specification and the configurations shown in the drawings are only the most preferred embodiments of the present invention and represent all the technical ideas of the present invention. Since it is not, it should be understood that there may be various equivalents and modifications that can replace them at the time of this application. Therefore, the embodiments described above should be understood as illustrative and not restrictive in all respects, and the scope of the present invention is indicated by the claims to be described later rather than the detailed description, and the meaning and scope of the claims and their All changes or modified forms derived from equivalent concepts should be construed as being included in the scope of the present invention.

10 : Groove
11 : Sub Groove
111: first sub groove
113: 2nd sub groove
115: 3rd sub groove
12: Cavity

Claims (6)

In the tire tread structure including a groove formed in the circumferential direction,
The groove,
A sub-groove extending radially from the tread surface;
A tire tread structure comprising a cavity extending from one end of the sub-groove and forming a predetermined space therein. According to claim 1,
The tire tread structure, characterized in that the width of the sub-groove expands toward the radial direction, so that the entire groove is formed in a raindrop shape. According to claim 1,
The sub groove,
A first sub-groove extending from the upper right corner of the cavity along the circumferential direction of the tire;
A second sub-groove extending from the upper left corner of the cavity along the circumferential direction of the tire; and
The tire tread structure of claim 1, further comprising a third sub-groove extending obliquely in a circumferential direction so as to interconnect the first sub-groove and the second sub-groove. According to claim 1,
The tire tread structure, characterized in that the angle (Ai) formed with the upper portion of the cavity based on the central axis of the sub-groove is 30 to 65 °. According to claim 1,
The tire tread structure, characterized in that the ratio of the width (WRi) of the cavity to the width (WRo) of the sub-groove, WRi/WRo, is 12 to 28. According to claim 1,
The tire tread structure, characterized in that Di / Do, which is the ratio of the length (Di) of the cavity to the total length (Do) of the groove, is 0.4 to 0.8.

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