Three-dimensional tire profile having a variable cross-section

Abstract

Various aspects of a tire having a three-dimensional tire sipe with a variable cross section are disclosed. In one aspect, a tire is provided having a sipe, the sipe being a three-dimensional sipe extending radially inward into the tire from a tread surface of the tire, the sipe including a horizontal wavy portion having at least one horizontal midpoint portion and at least one horizontal peak portion, the sipe including a radial wavy portion having a vertical amplitude VA1 of the at least one horizontal midpoint portion and a vertical amplitude VA2 of the at least one horizontal peak portion, the vertical amplitude VA1 being greater than the vertical amplitude VA2.

Description

Background Art

[0001] Tires for use on vehicles may include a tread characterized by sipes. The presence of sipes in a tire tread can create more surface edges for engaging the road lane, increasing traction in adverse road conditions. For example, a tire tread including sipes can function better in frozen, snowy, or wet road conditions than a tire tread without sipes. Similarly, in adverse road conditions, the more sipes a tire has, the better traction it can exhibit.

[0002] However, adding sipes to a tire tread block can reduce block stiffness, which can result in an undesirable irregular wear pattern in the tire and a reduction in tire performance in dry road conditions (i.e., non - adverse conditions). Increasing the number of sipes in a tire tread block can be associated with a reduction in the stiffness of that tire tread block.

[0003] To regain at least some of the stiffness lost in the tread block by increasing the number of sipes, it may be desirable to form sipes having a connecting shape. It may be desirable to create connecting sipes that are as thin as possible in those connecting areas. This configuration can improve braking performance on dry surfaces. Additionally, in the case of tires with a deep tread depth, the sipes must be made deeper (and thus the sipes blades higher) to achieve the desired functional enhancement. Thus, it may be desirable to create sipes blades configured to form sipes that are as thin as possible and / or as high as possible while maintaining the durability of the sipes blades within the tire mold.

Summary of the Invention

Problems to be Solved by the Invention

[0004] There is a need for a connecting tire sipe configured to provide sufficient block rigidity and / or braking performance while making it possible to make the sipe as thin and / or as high as possible while maintaining the durability of the sipe blade within the tire mold.

[0005] In one aspect, there is provided a tire having sipes, wherein the sipes are three-dimensional sipes extending radially inwards from the tread surface of the tire into the tire, the sipes include a horizontal wavy portion having at least one horizontal midpoint portion and at least one horizontal peak portion, the sipes include a radial wavy portion having a vertical amplitude VA1 of at least one horizontal midpoint portion and a vertical amplitude VA2 of at least one horizontal peak portion, and the vertical amplitude VA1 is greater than the vertical amplitude VA2.

[0006] In another aspect, there is provided a tire having sipes, wherein the sipes are three-dimensional sipes extending radially inwards from the tread surface of the tire into the tire, the sipes include a horizontal wavy portion having at least one horizontal midpoint portion and at least one horizontal peak portion, the sipes include a radial wavy portion having a vertical amplitude VA1 of at least one horizontal midpoint portion and a vertical amplitude VA2 of at least one horizontal peak portion, the vertical amplitude VA1 is greater than the vertical amplitude VA2, the value of the vertical amplitude VA1 is from the value of the vertical amplitude VA2 to 1.50 mm, and the value of the vertical amplitude VA2 is from 0.00 mm to the value of the vertical amplitude VA1.

Brief Description of the Drawings

[0007] The accompanying drawings, which are incorporated herein and constitute a part of this specification, illustrate the configurations of various examples and are used merely to illustrate various exemplary embodiments. In the drawings, like elements have like reference numerals.

Figure 1A

Figure 1B

Figure 1C

Figure 1D

Figure 2A

Figure 2B

[0008] Tires not intended for operation on a smooth, dry surface generally comprise a tread pattern including at least one groove, at least one rib, and / or a plurality of tread blocks. For example, a tire intended for operation in severe conditions including freezing or snow-covered conditions may additionally comprise a plurality of sipes in the tire tread. Adding sipes to the tire tread can create more surface edges on the tire tread for engaging a frozen or snow-covered road surface.

[0009] Increasing the length of the sipes, such as by providing a three-dimensional pattern to the sipes, can increase the amount and length of cutting edges available for engaging a snow-covered, frozen, and / or wet road surface.

[0010] By providing sipes having a three-dimensional pattern in at least one of the lateral direction and the radial direction of the tire, it is possible to engage the opposing walls of the sipes at least partially with each other with high friction or in a locking manner to maintain the desired rigidity of the tire tread block or the tire tread rib. By maintaining the rigidity of the tire tread at a specified level, an irregular wear pattern can be reduced or eliminated. By maintaining the rigidity of the tire tread at a specified level, the stopping distance of the tire can be improved. By maintaining the rigidity of the tire tread at a specified level, the traction of the tire can be improved.

[0011] It may be advantageous to provide the thinnest possible connecting three-dimensional sipes in those connecting regions. Thus, a sipe thickness (and thus sipe blade thickness) of 0.3 mm or less may provide advantageous results. Further, a sipe thickness (and thus sipe blade thickness) of less than 0.3 mm may be even more advantageous.

[0012] However, the sipe blades used to form sipes having the desired traction while maintaining the desired block rigidity are often made as thin as possible, which can lead to durability problems with the sipe blades.

[0013] Figures 1A - 1D illustrate a three-dimensional sipe 120 having a variable cross-section.

[0014] Figure 1A illustrates a tire tread 100 having a tread surface 102 and at least one rib / block row 104, 106, 108, 110 separated by at least one groove 112, 114, 116. At least one rib / block row 104, 106, 108, 110 includes at least one three-dimensional sipe 120. At least one rib / block row 104, 106, 108, 110 may include at least one slot 118.

[0015] For consistency, the X-axis is oriented in the circumferential direction of the tire, the Y-axis is oriented in the axial direction of the tire, and the Z-axis is oriented in the radial direction of the tire.

[0016] FIG. 1B illustrates a plan view of the three-dimensional sipe 120. The sipe 120 extends radially inwards from the tread surface 102. The sipe 120 may include a tip portion 122 that may be the axially outermost end of the sipe 120. The sipe 120 may include a horizontal undulating portion 124. The horizontal undulating portion 124 is oriented between horizontal non-undulating portions 126 that extend to the tip portion 122.

[0017] The horizontal undulating portion 124 may form a wavy portion, which may be a sine wave, on the tread surface 102. Alternatively, the horizontal undulating portion 124 may be linear elements angled with respect to each other and connected by curves / fillets. The horizontal undulating portion 124 of the sipe 120 includes a horizontal peak portion 128 and a horizontal midpoint portion 130. FIG. 1C illustrates a cross-sectional view of the sipe 120 at the horizontal midpoint portion 130 (cut along section A-A), while FIG. 1D illustrates a cross-sectional view of the sipe 120 at the horizontal peak portion 128 (cut along section B-B). These cross-sectional views of the sipe 120 include a radially undulating portion 136 having different vertical amplitudes VA1, VA2, as further described below.

[0018] The horizontal undulating portion 124 may have a surface thickness TS. The surface thickness TS may range from a value of the internal thickness TI (see FIGS. 1C and 1D) of ~1.50 mm. The surface thickness TS may be from 0.05 mm to 1.50 mm. The surface thickness TS may be 0.60 mm.

[0019] At least a portion of the horizontal non-undulating portion 126 may intersect the grooves 112, 114, 116, and the horizontal non-undulating portion 126 may include a sipe thickness equal to the surface thickness TS through the radial depth of the sipe 120. The tip portion 122 may include a sipe thickness equal to the surface thickness TS through the radial depth of the sipe 120.

[0020] The horizontal corrugated portion 124 may have a horizontal period HP. The horizontal period HP may be from 4.50 mm to 15.00 mm. The horizontal period HP may be 7.50 mm, 6.64 mm, or 10.40 mm.

[0021] The horizontal corrugated portion 124 may have a horizontal amplitude HA. The horizontal amplitude HA is measured from the center line of the cycle 120 at the horizontal peak portion 128. The horizontal amplitude HA may be from 1.50 mm to 3.50 mm. The horizontal amplitude HA may be 2.40 mm or 2.11 mm.

[0022] The horizontal corrugated portion 124 may have a horizontal angle A1 measured between the center line of the cycle 120 (for example, a line parallel to the horizontal non - corrugated portion 126 and extending longitudinally downward from the center thereof) and the center line of the horizontal intermediate point portion 130. The horizontal angle A1 may be from 35 degrees to 55 degrees. The horizontal angle A1 may be 45 degrees.

[0023] FIG. 1C illustrates the cycle 120 cut along the section A - A illustrated in FIG. 1B, and FIG. 1D illustrates the cycle 120 cut about the section B - B illustrated in FIG. 1B. The cycle 120 may include a radially outer portion 132 that may include a sloped wall or a parallel wall (when TS = TI) transitioning between a surface thickness TS and an internal thickness TI. The cycle 120 may include a radially inner portion 134 that may include a sloped wall or a parallel wall (when TI = TB) transitioning between the internal thickness TI and a base thickness TB. The cycle 120 may include a radially corrugated portion 136 oriented between the radially outer portion 132 and the radially inner portion 134. The radially inner portion 134 may have a rounded base.

[0024] The internal thickness TI may be from 0.05 mm to the surface thickness TS. The internal thickness TI may be from 0.05 mm to 1.50 mm. The internal thickness TI may be 0.15 mm or 0.30 mm.

[0025] The base thickness TB can be in the range of the value of the internal thickness TI to 1.50 mm. The base thickness TB can be 0.05 mm to 1.50 mm. The base thickness TB can be 0.60 mm. The base thickness TB can be equal to the surface thickness TS.

[0026] The radial corrugated portion 136 can form a corrugated portion that can be a sine wave. Alternatively, the radial corrugated portion 136 can be linear elements that are angled with respect to each other and connected by curves / fillets.

[0027] The total depth D of the sip 120 can be 4.50 mm to 20.00 mm. The depth D can be 6.30 mm, 6.80 mm, 6.70 mm, or 11.18 mm.

[0028] The first radially inward peak of the radial corrugated portion 136 can have a depth P1 of about 1.20 mm to 2.40 mm from the tread surface 102. The depth P1 can be 1.70 mm.

[0029] The radial corrugated portion 136 can include a vertical period VP. The vertical period VP can be 1.60 mm to 3.50 mm. The vertical period VP can be 2.30 mm or 2.50 mm.

[0030] Referring particularly to FIGS. 1C and the sip 120 of the horizontal midpoint portion 130, the radial corrugated portion 136 can include a vertical amplitude VA1. The vertical amplitude VA1 can be the vertical amplitude VA2 to 1.50 mm. The vertical amplitude VA1 can be 0.82 mm or 1.00 mm. The vertical amplitude VA1 is greater than the vertical amplitude VA2.

[0031] The sip 120 of the horizontal midpoint portion 130 can include a radial corrugated portion 136 having a radius R1. The radius R1 can be 0.15 mm to 1.50 mm. The radius R1 can be 0.15 mm.

[0032] The radial corrugated portion 136 may have a radial angle RA1 measured between a cycle 120 (e.g., a line parallel to the radial direction, Z-axis) and the center line of the cycle 120. The radial angle RA1 may be from the radial angle RA2 to 45 degrees. The radial angle RA1 may be 41 degrees.

[0033] Referring particularly to FIGS. 1D and the cycle 120 of the horizontal peak portion 128, the radial corrugated portion 136 may include a vertical amplitude VA2. The vertical amplitude VA2 may be from a vertical amplitude of 0.00 mm to VA1. The vertical amplitude VA2 may be 0.23 mm or 0.70 mm. The vertical amplitude VA2 is less than the vertical amplitude VA1.

[0034] The cycle 120 of the horizontal peak portion 128 can include a radial corrugated portion 136 having a radius R2. The radius R2 is larger than the radius R1. The radius R2 may be 0.63 mm or 4.45 mm.

[0035] The radial corrugated portion 136 may have a radial angle RA2 measured between a cycle 120 (e.g., a line parallel to the radial direction, Z-axis) and the center line of the cycle 120. The radial angle RA2 may be from 0 degrees to the angle RA1. The radial angle RA2 may be 13 degrees or 4 degrees.

[0036] Between the horizontal midpoint portion 130 and the horizontal peak portion 128, the cycle 120 has a smooth mixed transition between two cycle profiles illustrated in FIGS. 1C and 1D where the vertical amplitude transitions between the vertical amplitudes VA1 and VA2.

[0037] FIGS. 2A and 2B illustrate cross-sectional views of a three-dimensional cycle 220 having a vertical corrugated portion 236 with a radial period of 1.5 (FIG. 2A) and a radial period of 2.5 (FIG. 2B). The cycle 220 may extend radially inward from the tread surface 202 and may include a radially outer portion 232, a radially inner portion 234, and a radial corrugated portion 236.

[0038] The radially corrugated portion 236 may include one or more full-cycle portions 240 and / or one or more half-cycle portions 242. The radially corrugated portion 236 may include a period of 1.0 to 8.0. The radially corrugated portion 236 may include a period of 1.5, a period of 2.5, or a period of 3.5.

[0039] The different amplitudes (VA1 and VA2) described herein can act to improve the strength of the sip blades used to fabricate the sips 120, 220 while minimizing the thickness of the sip blades (sips 120, 220) without concerns regarding the durability of the blades. The sip blades used to fabricate the sips 120, 220 may be made "higher" radially for a greater overall depth D without concerns regarding the durability of the blades. The sips 120, 220 may exhibit improved dry braking (2.5% improvement over prior art sips) and improved wet performance (2.0% improvement over prior art sips).

[0040] As used in this specification or the claims, the terms "includes" or "including" are intended to be inclusive in the same sense as the term "comprising" as construed when used as a transitional phrase in a claim. Further, where the term "or" is used (e.g., A or B), it is intended to mean "A or B, or both." Where Applicants intend to indicate "only A or B but not both," the term "only A or B but not both" is used. Accordingly, the use of the term "or" in this specification is not exclusive but inclusive. See Bryan A. Garner, A Dictionary of Modern Legal Usage 624 (2d Ed. 1995). Also, as used in this specification or the claims, the terms "in" or "into" are intended to additionally mean "on" or "onto." The term "substantially" as used in this specification or the claims is intended to account for manufacturing availability or a degree of precision that is common sense. The term "selectively" as used in this specification or the claims is intended to refer to a component state where the user of the device can activate or deactivate a component feature or function as needed or desired during use of the device. The term "operatively connected" as used in this specification or the claims is intended to mean that the specified component is connected so as to perform the specified function. When used in this specification and the claims, the singular forms "a," "an," and "the" include the plural. Finally, when the term "about" is used in conjunction with a numerical value, it is intended to encompass ±10% of that numerical value. In other words, "about 10" can mean from 9 to 11. The Cartesian coordinates referred to in this specification are intended to correspond to the SAE tire coordinate system.

[0041] As described above, this application is illustrated by the description of its aspects, which have been described in considerable detail. However, it is not the intention of the applicants to limit the scope of the appended claims to such detail or in any way. Additional advantages and modifications will readily become apparent to those skilled in the art while enjoying the benefits of this application. Accordingly, this application is not limited to the specific details, illustrative examples, or any apparatus referred to in a broader aspect of this application. Departures from such details, examples, and apparatus may be made without departing from the spirit or scope of the overall inventive concept.

Claims

1. A tire having sipes, wherein the sipes are three-dimensional sipes extending radially inwards from the tread surface of the tire into the tire, the sipes include a horizontal wavy portion having a plurality of horizontal intermediate point portions and a plurality of horizontal peak portions, the sipes include a radial wavy portion having a vertical amplitude VA1 of each of the plurality of horizontal intermediate point portions and a vertical amplitude VA2 of each of the plurality of horizontal peak portions, a tire in which any of the vertical amplitudes VA1 is greater than any of the vertical amplitudes VA2.

2. The tire according to claim 1, wherein any value of the vertical amplitude VA1 is a value between any value of the vertical amplitude VA2 and 1.50 mm.

3. The tire according to claim 1, wherein any value of the vertical amplitude VA2 is a value between 0.00 mm and any of the vertical amplitudes VA1.

4. The tire according to claim 1, wherein the radial wavy portion includes a vertical period, and the vertical period is 1.60 mm to 3.50 mm.

5. The tire according to claim 1, wherein the radial wavy portion includes a period of 1.0 to 8.0.

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