High performance tire
By designing specific groove structures in the center, outer shoulder, and inner shoulder areas of the tire tread and using a low void rubber ratio, the problems of insufficient grip on wet roads and high noise on dry roads in high-performance car tires have been solved, achieving high-performance performance on both roads and racetracks.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- PIRELLI TYRE SPA
- Filing Date
- 2022-03-24
- Publication Date
- 2026-06-02
AI Technical Summary
Existing high-performance or ultra-high-performance car tires have insufficient grip on wet surfaces and their performance deteriorates at high speeds on dry surfaces, resulting in higher noise levels. They are difficult to perform well on both roads and racetracks.
Design a tire tread belt including a central area, an outer shoulder area and an inner shoulder area, the outer shoulder area and the inner shoulder area having different groove structures, the groove width and slope of the outer shoulder area being different, and the central area having a low void rubber ratio to improve grip and reduce noise.
Maintain high performance on the track while ensuring safety and grip on wet surfaces, reducing noise, suitable for both road and track environments.
Smart Images
Figure CN117241949B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a car tire, and more particularly to a high-performance or ultra-high-performance car tire for both road and track use. Background Technology
[0002] The following documents describe some examples of high-performance or ultra-high-performance car tires: WO2009 / 004408, WO2015 / 008137, WO02 / 078982, WO2019 / 111089. Summary of the Invention
[0003] High-performance or ultra-high-performance car wheels and tires (which are also designed for the track) need to provide performance, steering precision, and excellent ground grip in order to effectively transfer high torque to the ground and withstand high lateral stress, even at the high operating temperatures associated with track use.
[0004] Using "smooth" tires (like those used in racing cars) and / or tires with a very low (almost zero) rubber-to-void ratio can yield better results in terms of performance and grip.
[0005] However, while these tires perform exceptionally well on the track, they are generally unsuitable for road use due to their lower safety parameters in wet conditions. Under certain weather conditions, precipitation wets the road surface, significantly reducing tire grip and compromising road grip, traction, and effective braking.
[0006] The applicant noted that, generally, when driving on wet surfaces, attempts are made to increase the number and / or size of grooves in both the circumferential and lateral directions in order to affect drainage in the tire contact area (footprint area).
[0007] Wide and deep grooves increase the rubber-to-void ratio of the tread belt, which has a positive impact on the tire's drainage and grip characteristics when driving on wet roads.
[0008] However, wide and deep grooves in the circumferential and / or lateral directions reduce the stiffness of the tread band, thus increasing the risk of performance degradation at high speeds on dry roads. Furthermore, the presence of grooves can generate noise.
[0009] It is evident that high-performance or ultra-high-performance car tires designed for both road and track use must meet several conflicting requirements to deliver good performance in every different road and weather condition.
[0010] Therefore, the problem facing applicants is to provide such car tires, especially high-performance or ultra-high-performance car tires designed for both road and track use, which can ensure high performance levels in straight-line driving, cornering, braking and traction, as well as low noise, without compromising drainage and safety characteristics on wet surfaces.
[0011] To achieve this improvement, the applicant has focused its efforts on producing a tire whose tread belt has a central region (preferably with a limited extension) separated from two wide shoulder regions (a wider outer shoulder region and a narrower inner shoulder region, respectively). Both the outer and inner shoulder regions have relatively wide grooves. In the outer shoulder region, these grooves intersect with other narrower grooves, moderately reducing the stiffness of that region of the tire. The central region of the tire is designed to have a lower void-to-rubber ratio, resulting in a controlled mixture of rubber in contact with the ground and yielding portions of the tread belt overall, achieving optimal performance and driving readiness.
[0012] The first aspect of the present invention relates to an automobile tire having:
[0013] The tread belt includes a central region extending across the equatorial plane of the tire, an outer shoulder region positioned toward the outer side of the tire, and an inner shoulder region positioned toward the inner side of the tire.
[0014] A first circumferential groove axially defines the outer shoulder region relative to the central region and a second circumferential groove axially defines the inner shoulder region relative to the central region;
[0015] The width of the outer tire shoulder area is greater than the width of the inner tire shoulder area;
[0016] The outer shoulder region and the inner shoulder region include a plurality of first lateral grooves, each first lateral groove having a first end substantially located at the corresponding edge of the tread band, the first lateral groove having a maximum width greater than or equal to 3 mm, and an extension range at least equal to 50% of the width of the shoulder region where the first lateral groove is located.
[0017] And among them,
[0018] The outer shoulder area includes a plurality of second lateral grooves that extend substantially from the first circumference toward the groove;
[0019] The width of the second lateral groove is smaller than the width of the first lateral groove, and it has a reverse sloping direction relative to the first lateral groove in the outer tire shoulder area;
[0020] The central region includes a first circumferential rib and a second circumferential rib separated by a third circumferential groove.
[0021] The void rubber ratio of the first circumferential rib and the second circumferential rib is equal to or less than 0.09.
[0022] The applicant discovered that, thanks to these features, the tire of the present invention can achieve high performance levels even on the racetrack, while also being low in noise and ensuring driving safety on wet surfaces.
[0023] Without being bound by any specific theory, the applicant believes that a wider tire shoulder area improves grip, especially during high-speed cornering, while lateral grooves of varying widths and positions and inclined in opposite directions within this area improve traction and braking performance by controlling the "lateral pull" phenomenon (i.e., limiting the generation of stress on the tire in the lateral direction during straight driving).
[0024] For the purposes of this invention, the following definitions apply:
[0025] "Tread pattern" refers to the representation of all points on the tread band (including grooves) in a plane perpendicular to the equatorial plane of the tire and tangent to the tire's maximum diameter.
[0026] Measurements of angles and / or linear quantities (distance, width, length, etc.) and / or surface areas are all taken with reference to the tread pattern as defined above.
[0027] Furthermore, regarding the angular arrangement of the grooves formed in the tread band relative to the equatorial plane of the tire, this angular arrangement should be understood as the acute angle formed by rotating from the equatorial plane to the tangent direction of the groove passing through that point for each point of the groove (i.e., an angle with an absolute value between 0° and 90°).
[0028] The term "equatorial plane" of a tire refers to a plane perpendicular to the tire's axis of rotation that divides the tire into two substantially equal parts.
[0029] The term "circumferential" direction refers to the direction that is basically oriented in accordance with the direction of tire rotation, or the direction that is slightly inclined (e.g., up to about 20°) relative to the direction of tire rotation.
[0030] The "axial" direction refers to the direction that is substantially parallel to the tire's axis of rotation, or at most slightly inclined (up to about 20°) relative to the tire's axis of rotation. Generally speaking, the axial direction is substantially perpendicular to the circumferential direction.
[0031] The term "effective width" of a tread band refers to the width of the outermost radial portion of the tread band (from one edge to the other) that is intended to contact the ground.
[0032] The so-called "void-to-rubber ratio" refers to the ratio of the total surface area of the grooves in a specific part (which may be the entire tread belt) to the total surface area of that specific part (which may be the entire tread belt).
[0033] In one or more preferred aspects, the invention may include one or more features described below.
[0034] Ideally, the first transverse groove can have a substantially straight orientation.
[0035] Preferably, the gap rubber ratio in the inner tube shoulder area can be formed solely by the first lateral groove.
[0036] Advantageously, in the inner tube shoulder region, the extension range of the first lateral groove can be equal to or less than 90% of the width of the inner tube shoulder region.
[0037] Preferably, the number of the first lateral grooves in the outer tire shoulder region can be less than the number of the first lateral grooves in the inner tire shoulder region.
[0038] Ideally, the number of first lateral grooves in the inner shoulder region is approximately twice the number of first lateral grooves in the outer shoulder region.
[0039] Advantageously, the second transverse groove can be tilted relative to a direction parallel to the equatorial plane to form an angle greater than 75°.
[0040] Preferably, the extension range of the second lateral groove can be equal to or less than 90% of the width of the outer tire shoulder area.
[0041] Advantageously, the second transverse groove does not intersect with the first transverse groove.
[0042] Ideally, in the outer tire shoulder region, the extension range of the second lateral groove and the first lateral groove may have a segment located in a common circumferential annular portion, the width of which is at least 1 / 5 of the width of the outer tire shoulder region.
[0043] Advantageously, in the outer tire shoulder region, the extension range of the second lateral groove and the first lateral groove can have a segment located in a common circumferential annular portion, the width of which is at most equal to 2 / 5 of the width of the outer tire shoulder region.
[0044] Preferably, the first circumferential rib includes a third transverse groove.
[0045] To avoid significant stiffness changes in the axial direction, the third transverse groove is preferably positioned along the extension direction of the second transverse groove.
[0046] Advantageously, the extension range of the third transverse groove can be equal to or less than 80% of the width of the first circumferential rib.
[0047] Preferably, the extension range of the third transverse groove can be equal to or less than 50% of the width of the first circumferential rib.
[0048] Appropriately, the second circumferential rib may include a fourth transverse groove.
[0049] Preferably, the extension range of the fourth transverse groove can be equal to or greater than 50% of the width of the second circumferential rib.
[0050] Preferably, the fourth transverse groove can extend over the entire width of the second circumferential rib.
[0051] Ideally, the fourth transverse groove may have at least one first segment and at least one second segment continuously positioned relative to the first segment.
[0052] Preferably, the second segment may be tilted in the opposite direction to the first segment.
[0053] Advantageously, the first section of the fourth transverse groove can extend from the third circumference into the groove.
[0054] Preferably, in order to avoid significant stiffness changes in the axial direction within the groove, the first section of the fourth transverse groove can be extended to be positioned along the extension direction of the second transverse groove.
[0055] Advantageously, the first segment of the fourth trench extends over a maximum of 20% of the total extension range of the fourth transverse trench.
[0056] Ideally, the second segment of the fourth trench extends over at least 50% of the total extension of the fourth transverse trench.
[0057] Preferably, the second segment of the fourth transverse groove has a first portion with a width equal to or greater than 3 mm.
[0058] Ideally, the second segment of the fourth transverse groove could have a second segment with a width smaller than that of the first segment.
[0059] In some embodiments, the outer tire shoulder region includes multiple longitudinal grooves having a generally circumferential orientation.
[0060] Advantageously, the longitudinal groove intersects with at least some of the first transverse groove.
[0061] Advantageously, the longitudinal groove is connected to at least some of the second transverse groove.
[0062] Preferably, the void rubber ratio of the first circumferential rib can be generated solely by the third transverse groove.
[0063] In another embodiment, the first circumferential rib may include a plurality of fifth transverse grooves.
[0064] Advantageously, the extension range of the fifth transverse groove can be equal to or less than 50% of the width of the first circumferential rib.
[0065] Preferably, the width of the fifth transverse groove can be greater than the width of the third transverse groove.
[0066] Preferably, the void rubber ratio of the second circumferential rib can be formed solely by the fourth transverse groove.
[0067] In another embodiment, the second circumferential rib may include a plurality of sixth transverse grooves.
[0068] Advantageously, the extension range of the sixth transverse groove can be equal to or greater than 50% of the width of the second circumferential rib.
[0069] Appropriately, the central region includes a third circumferential rib, which is separated from the first circumferential rib by a fourth circumferential groove.
[0070] Advantageously, the void rubber ratio of the third circumferential rib is equal to or less than 0.09.
[0071] Preferably, the third circumferential rib may include a plurality of seventh transverse grooves.
[0072] Ideally, the extension of the seventh transverse groove can be equal to or greater than 60% of the width of the third circumferential rib.
[0073] Preferably, the seventh transverse groove can extend over the entire width of the third circumferential rib.
[0074] Advantageously, the seventh transverse groove can extend from the first circumference into the groove.
[0075] Preferably, the seventh transverse groove can be extended to be positioned along the extension direction of the second transverse groove.
[0076] Ideally, the seventh transverse groove may have a first part and a second part, wherein the width of the second part is smaller than the width of the first part.
[0077] Other features and advantages of the invention will become clearer from the detailed description of some preferred (though not exclusive) embodiments of the invention, also intended for use in high-performance or ultra-high-performance car tires on the racetrack. Attached Figure Description
[0078] The following description will refer to the accompanying drawings, which are for illustrative purposes only and are not intended to be limiting.
[0079] - Figure 1A view showing an example of a tire according to the present invention;
[0080] - Figure 2 yes Figure 1 An enlarged view of the cross-section of the tire;
[0081] - Figure 3 yes Figure 1 A plan view of the tread band portion of a tire;
[0082] - Figure 4 This is a plan view of the tread strip portion of a second example of a tire according to the present invention;
[0083] - Figure 5 This is a plan view of the tread strip portion of a third example of a tire according to the present invention; and
[0084] - Figure 6 This is a plan view of the tread strip portion of a fourth example of a tire according to the present invention. Detailed Implementation
[0085] Referring to the attached diagram, tires used for automobile wheels, especially for high-performance or ultra-high-performance automobile wheels (which are also intended for use on the track), are generally marked as 100.
[0086] The tire 100 has a conventional structure and includes a carcass, a tread band 1 positioned as the crown of the carcass, and a pair of axially opposed sidewalls ending at a bead reinforced by a bead core and associated bead filler. The tire preferably also includes a belt structure inserted between the carcass and the tread band. The carcass includes one or more carcass layers anchored to the bead core, while the belt structure includes two radially stacked belt strips. The belt strips are formed from sheets of rubber fabric incorporating metal cords that are parallel to each other in each strip and have a cross-orientation (preferably, a symmetrical inclination relative to the equatorial plane) with respect to the cords of adjacent strips. At a radially outer position, the belt structure preferably also includes a third belt layer provided with cords oriented substantially parallel to the equatorial plane. Preferably, but not necessarily, the nominal section width of the tire according to the invention is at least about 205, more preferably at least about 225. For example, the nominal section width of the tire can be 225, 245, 275, 295, or 355. Preferably, the tire according to the invention has a small section height. For example, the section height may be less than or equal to 60% of the nominal section width, more preferably less than or equal to 50% of the nominal section width.
[0087] The tread band 1 has a low overall void rubber ratio, which is preferably less than or equal to 0.30, more preferably less than or equal to 0.26, and even more preferably less than or equal to 0.20.
[0088] The overall void rubber ratio of the tread band 1 is preferably greater than 0.14.
[0089] Preferably, but not necessarily, the tire according to the invention is of an asymmetrical type, that is, the tread pattern on the right side of the equatorial plane XX of the tire is substantially different from the tread pattern on the left side. Therefore, when the tire 100 and / or the tread belt 1 are installed, they have an inner side preferably arranged toward the inside of the vehicle (located on the right side in the example shown in the figure) and an outer side preferably arranged toward the outside of the vehicle (located on the left side in the example shown in the figure).
[0090] The tread band 1 has at least two circumferential grooves extending generally in the circumferential direction, namely a first circumferential groove 2 and a second circumferential groove 3.
[0091] The first circumferential groove 2 and the second circumferential groove 3 separate the central region L1 of the tread band 1 from the outer shoulder region L2 and the inner shoulder region L3 of the tread band 1, which are located on the left and right sides of the central region L1, respectively. The outer shoulder region L2 is located on the outside of the tire, while the inner shoulder region L3 is located on the inside of the tire.
[0092] The central region L1 extends across the equatorial plane XX of the tire. The outer shoulder region L2 and the inner shoulder region L3 extend to the axial ends near the tread band 1.
[0093] exist Figure 1-5 In the embodiment shown, the central region L1 occupies a limited portion of the tread band 1.
[0094] In these embodiments, the width of the central region L1 may be less than or equal to 35% of the effective width of the tread band 1 (i.e., the width of the area of the tread band 1 intended to contact the ground). The width of the outer shoulder region L2 is greater than 30% of the effective width of the tread band 1; the width of the inner shoulder region L3 is less than 35% of the effective width of the tread band 1.
[0095] exist Figure 6 In the illustrated embodiment, the width of the central region L1 may be less than or equal to 50% of the effective width of the tread band 1; the width of the outer shoulder region L2 is greater than 25% of the effective width of the tread band 1; and the width of the inner shoulder region L3 is less than 25% of the effective width of the tread band 1.
[0096] Preferably, in the tire 100 of the present invention, the width of the outer shoulder region L2 is greater than the width of the inner shoulder region L3.
[0097] The first circumferential groove 2 defines the outer shoulder area L2 in the axial direction relative to the central area L1 of the tread band 1, while the second circumferential groove 3 defines the inner shoulder area L3 in the axial direction relative to the central area L1.
[0098] Preferably, the first circumferential groove 2 and the second circumferential groove 3 have a substantially straight orientation in the circumferential direction, preferably along the entire circumferential extension of the tire.
[0099] The width of the first circumferential groove 2 can be different from that of the second circumferential groove 3.
[0100] exist Figure 1-4 and Figure 6 In the illustrated embodiment, the width of the first circumferential groove 2 is smaller than the width of the second circumferential groove 3. For example, in these embodiments, the width of the first circumferential groove 2 may be less than 50% of the width of the second circumferential groove 3.
[0101] In these cases, the primary function of the first circumferential groove 2 is to provide substantial continuity of performance between the outermost portions of the outer shoulder region L2 and the central region L1, and therefore the function of draining water from the footprint region is mainly assigned to the other circumferential grooves described below.
[0102] exist Figure 1-4 and Figure 6 In the illustrated embodiment, the width of the first circumferential groove 2 may be, for example, less than or equal to about 8 mm, more preferably less than or equal to about 6 mm, and in any case greater than or equal to about 2 mm.
[0103] exist Figure 5 In the illustrated embodiments, the width of the first circumferential groove 2 is approximately equal to or slightly larger than the width of the second circumferential groove 3. For example, in these embodiments, the width of the first circumferential groove 2 may be up to about 20% larger than the width of the second circumferential groove 3.
[0104] Preferably, in Figure 1-6 In the illustrated embodiment, the width of the second circumferential groove 3 may be greater than or equal to about 8 mm, more preferably greater than or equal to about 10 mm, and in any case less than or equal to about 15 mm.
[0105] Preferably, the depth of the first circumferential groove 2 and the second circumferential groove 3 can be less than or equal to about 8 mm, and in any case greater than or equal to about 2 mm.
[0106] exist Figure 1-6 In all the embodiments shown, the tread band 1 also includes a third circumferential groove 4 located in the central region L1.
[0107] The third groove 4 preferably also has a basically straight orientation.
[0108] The width of the third circumferential groove 4 is preferably greater than the width of the first circumferential groove 2.
[0109] exist Figure 1-4In one embodiment, the width of the third circumferential groove 4 is smaller than the width of the second circumferential groove 3.
[0110] exist Figure 5-6 In one embodiment, the width of the third circumferential groove 4 is greater than the width of the second circumferential groove 3.
[0111] Preferably, in all four embodiments, the width of the third circumferential groove 4 is greater than or equal to about 7 mm, more preferably greater than or equal to about 8 mm, and in any case less than or equal to about 15 mm.
[0112] The depth of the third circumferential groove 4 may be less than or equal to about 9 mm, more preferably less than or equal to about 8 mm, and in any case greater than or equal to about 3 mm.
[0113] The depth of the first circumferential groove 2 is preferably equal to or less than the depth of the third circumferential groove 4. The depth of the second circumferential groove 3 is preferably equal to or less than the depth of the third circumferential groove 4.
[0114] Or refer to Figure 1-6 In the embodiment shown, at least the second circumferential groove 3 and the third circumferential groove 4 are configured to have straight cross sections with a generally trapezoidal shape.
[0115] In one embodiment, for example Figure 6 In the embodiment shown, the tread band 1 further includes a fourth circumferential groove 19 located in the central region L1.
[0116] The width of the fourth circumferential groove 19 is preferably greater than the width of the first circumferential groove 2 and the second circumferential groove 3, but less than the width of the third circumferential groove 4.
[0117] Preferably, the fourth circumferential groove 19 also has a basically straight orientation.
[0118] Preferably, the width of the fourth circumferential groove 19 may be greater than or equal to about 9 mm, more preferably greater than or equal to about 10 mm, and in any case less than or equal to about 18 mm.
[0119] The depth of the fourth directional groove 19 may be less than or equal to about 9 mm, more preferably less than or equal to about 8 mm, and in any case greater than 2 mm.
[0120] Preferably, the depth of the fourth circumferential groove 19 is equal to or less than the depth of the third circumferential groove 4.
[0121] The depth of the first circumferential groove 2 is preferably equal to or less than the depth of the fourth circumferential groove 19.
[0122] The depth of the second circumferential groove 3 is preferably equal to or less than the depth of the fourth circumferential groove 19.
[0123] The fourth directional groove 19 preferably has a straight cross section that is generally trapezoidal in shape.
[0124] The outer shoulder area L2 and the inner shoulder area L3 have good stiffness to provide the tire with a quick response, especially when driving at high speeds and cornering.
[0125] To make the tire shoulder area rigid, the outer shoulder area L2 and the inner shoulder area L3 have a restricted void rubber ratio.
[0126] The void rubber ratio in the outer tire shoulder region L2 and / or the inner tire shoulder region L3 is preferably less than about 0.20, and more preferably less than about 0.18.
[0127] The void rubber ratio in the outer tire shoulder region L2 and / or the inner tire shoulder region L3 is preferably greater than about 0.05, and more preferably greater than about 0.07.
[0128] The void rubber ratio in the inner tire shoulder region L3 is preferably greater than that in the outer tire shoulder region L2.
[0129] The inner shoulder area L3 includes a first lateral groove 6 that repeats in the circumferential direction.
[0130] The gap rubber in the inner tube shoulder region L3 is preferably formed only by such a first lateral groove 6.
[0131] In other words, other types of grooves and / or depressions (except for the second circumferential groove 3) are preferably absent in the inner tube shoulder area L3.
[0132] The first lateral groove 6 in the inner tube shoulder region L3 preferably has a substantially straight orientation.
[0133] The first lateral groove 6 of the inner tube shoulder region L3 preferably has a substantially lateral orientation or an orientation that is only slightly inclined relative to the axial direction.
[0134] In particular, the orientation of the first transverse groove 6 forms an angle with the equatorial plane XX with an absolute value between 75° and 90°.
[0135] The maximum width of the first lateral grooves 6 in the inner shoulder region L3 is greater than or equal to about 3 mm. Their maximum width is preferably less than about 8 mm. For example, their maximum width can be between about 3.5 and about 7 mm.
[0136] like Figure 1-3 , Figure 5 , Figure 6 In the example shown, the first lateral groove 6 of the inner shoulder region L3 can have a substantially constant width along its extension.
[0137] In another implementation, for example, Figure 4As shown in the example, the width of the first lateral groove 6 in the inner shoulder region L3 increases significantly in the direction away from the equatorial plane XX.
[0138] Preferably, the maximum depth of the first lateral groove 6 in the inner tire shoulder region L3 is at least about 2 mm and less than about 8 mm.
[0139] The depth of the first lateral groove 6 in the inner shoulder region L3 may not be constant along its corresponding extension range. For example, the depth decreases towards the axial outer edge of the tread band 1, preferably gradually.
[0140] The first lateral groove 6 of the inner shoulder region L3 has a first end located substantially at the corresponding axial outer edge of the tread band 1 and extends from the first end over at least 50% of the width of the inner shoulder region L3 in a substantially axial direction.
[0141] Preferably, the extension range of the first lateral groove 6 in the inner tube shoulder region L3 can be equal to or less than 70% of the width of the inner tube shoulder region L3. Alternatively, the extension range of the first lateral groove 6 in the inner tube shoulder region L3 can be equal to or less than 90% of the width of the inner tube shoulder region L3.
[0142] The first lateral groove 6 of the inner tube shoulder region L3 preferably does not have a point of intersection with the second circumferential groove 3.
[0143] In some implementations, such as Figure 5-6 As shown, some of the first grooves 6 can be connected to the second circumferential grooves 3 via transverse slots 6'.
[0144] The transverse groove 6' preferably extends from one end of the first transverse groove 6 to the second circumferential groove 3 in the axial direction.
[0145] The transverse groove 6' can have an extension of up to 15% of the width of the inner shoulder area L3.
[0146] like Figure 5 and Figure 6 In the example shown, the transverse slot 6' can have a substantially constant width along its extension.
[0147] like Figure 5 and Figure 6 In the example shown, the maximum width of the transverse slot 6' can be less than 2 mm.
[0148] like Figure 5 and Figure 6 In the example shown, the maximum depth of the transverse slot 6' can be less than 2 mm.
[0149] Preferably, the first lateral groove 6 of the inner tire shoulder region L3 does not all have lateral slots 6'.
[0150] exist Figure 5 and Figure 6 In the embodiment shown, the first transverse groove 6 having a transverse slot 6' and the first transverse groove 6 not having a transverse slot 6' are alternately arranged in the circumferential direction.
[0151] The outer tire shoulder area L2 includes at least a first lateral groove 5 and a second lateral groove 7 that alternate with each other in the circumferential direction.
[0152] Therefore, the void rubber ratio in the outer tire shoulder region L2 is formed by at least the first lateral groove 5 and the second lateral groove 7.
[0153] exist Figure 5 and Figure 6 In the embodiment shown, the outer tire shoulder region L2 also has a longitudinal groove 15, which will be described in detail below.
[0154] The number of first lateral grooves 5 in the outer tire shoulder region L2 is less than the number of first lateral grooves 6 in the inner tire shoulder region L3.
[0155] The number of first lateral grooves 6 in the inner shoulder region L3 is preferably about twice the number of first lateral grooves 5 in the outer shoulder region L2.
[0156] The first lateral groove 5 in the shoulder area L2 of the outer tire preferably has a substantially straight orientation.
[0157] The first lateral groove 5 of the outer tire shoulder region L2 preferably has a generally lateral orientation or an orientation that is only slightly inclined relative to the axial direction.
[0158] In particular, the orientation of the first lateral groove 5 in the outer tire shoulder region L2 forms an angle α with an absolute value between 75° and 90° with the equatorial plane XX.
[0159] like Figure 1 , Figure 3 , Figure 5 and Figure 6 As shown in the example, the first lateral groove 5 of the outer tire shoulder region L2 can have a substantially constant width along its extension.
[0160] In another implementation, for example, Figure 4 As shown, the difference is that the width of the first transverse groove 5 increases significantly in the direction away from the equatorial plane XX along its extension range.
[0161] The maximum width of the first lateral grooves 5 in the outer tire shoulder region L2 is greater than or equal to about 3 mm. Their maximum width is preferably less than about 8 mm. For example, their maximum width can be between about 3.5 and about 7 mm.
[0162] Preferably, the maximum depth of the first lateral groove 5 in the outer tire shoulder region L2 is at least about 2 mm and less than about 8 mm.
[0163] The depth of the first lateral groove 5 in the outer shoulder region L2 may be non-constant along its corresponding extension range; for example, its depth decreases, preferably gradually, in the direction toward the axial outer edge of the tread band 1.
[0164] The first lateral groove 5 of the outer shoulder region L2 has a first end located substantially at the corresponding axial outer edge of the tread band 1 and extends from the first end over at least 50% of the width of the outer shoulder region L2 in a substantially axial direction.
[0165] Preferably, the extension range of the first lateral groove 5 in the tire shoulder region L2 can be equal to or less than 70% of the width of the tire shoulder region L2. Alternatively, the extension range of the first lateral groove 5 in the tire shoulder region L2 can be equal to or less than 90% of the width of the tire shoulder region L2.
[0166] The first lateral groove 5 of the outer tire shoulder region L2 preferably does not have an intersection with the first circumferential groove 2.
[0167] The second lateral groove 7 located in the outer tire shoulder region L2 preferably extends from the first circumference toward the groove 2 in the basic axial direction by an amount of at least 20% of the width of the outer tire shoulder region L2.
[0168] Preferably, the extension range of the second lateral groove 7 is equal to or less than 90% of the width of the outer tire shoulder region L2.
[0169] Preferably, the second transverse groove 7 has a substantially straight orientation.
[0170] The second transverse groove 7 also has a basically transverse orientation or an orientation that is only slightly inclined relative to the axial direction but in the opposite direction to the first transverse groove 5.
[0171] In particular, the orientation of the second groove 7 forms an angle α' with the equatorial plane XX, with an absolute value between 75° and 90°, but with the opposite sign to the angle of the first transverse groove 5.
[0172] Preferably, the second lateral groove 7 and the first lateral groove 5 do not intersect, but they are positioned such that on the outer shoulder region L2, the extension range of the second lateral groove 7 and the first lateral groove 5 has a segment located in a common circumferential annular portion S.
[0173] Preferably, the width of the common circumferential annular portion S is at least equal to 1 / 5 of the width of the outer tire shoulder region L2.
[0174] Preferably, the width of the common circumferential annular portion S is at most equal to 2 / 5 of the width of the outer tire shoulder region L2.
[0175] The width of the second transverse groove 7 is smaller than the width of the first transverse grooves 5 and 6.
[0176] The maximum width of the second transverse grooves 7 is preferably less than about 3 mm. For example, their width can be between about 1.2 and about 3 mm.
[0177] The maximum depth of the second transverse groove 7 is preferably at least about 1.5 mm and less than about 4 mm.
[0178] In some embodiments, such as Figure 5 and Figure 6 In the embodiment shown, the outer tire shoulder region L2 may have multiple longitudinal grooves 15.
[0179] The longitudinal groove 15 extends to have a generally straight orientation in the basic circumferential direction.
[0180] The longitudinal groove 15 preferably extends in the circumferential direction to connect with at least some of the second transverse grooves 7, and preferably connects with all of the second transverse grooves 7.
[0181] The longitudinal grooves 15 preferably extend in the circumferential direction until they at least reach the first transverse groove 5.
[0182] exist Figure 5 In the embodiment shown, the longitudinal grooves 15 extend in the circumferential direction until they intersect with and slightly extend beyond the first transverse groove 5.
[0183] exist Figure 6 In the illustrated embodiment, the difference is that the longitudinal grooves 15 extend in the circumferential direction until they intersect with the first transverse grooves 5, but do not extend beyond the first transverse grooves in the circumferential direction.
[0184] exist Figure 5 and Figure 6 In the embodiment shown, each longitudinal groove 15 extends seamlessly from one end of the corresponding second transverse groove 7, i.e., forms a single groove with the corresponding second transverse groove.
[0185] The width of the longitudinal groove 15 is preferably smaller than the width of the first transverse grooves 5 and 6.
[0186] The width of the longitudinal grooves 15 is preferably less than about 4 mm. For example, their width can be between about 1.2 and about 3 mm.
[0187] The width of the longitudinal groove 15 is preferably substantially the same as the width of the second transverse groove 7.
[0188] The maximum depth of the longitudinal groove 15 is preferably at least about 1.5 mm and less than about 4 mm.
[0189] The central region L1 is designed to provide a larger amount of rubber in contact with the ground at the very center of the tread belt 1, that is, near the equatorial plane XX of the tire 1, so that the stiffness of the tread belt 1 is kept as uniform as possible.
[0190] Therefore, the void-to-rubber ratio of the central region L1 is less than about 0.40, preferably less than about 0.36. The void-to-rubber ratio of the central region L1 is preferably greater than about 0.25, and more preferably greater than about 0.28.
[0191] exist Figure 1-5 In the embodiment shown, the third circumferential groove 4, together with the first circumferential groove 2 and the second circumferential groove 3, defines the first circumferential rib 9 and the second circumferential rib 10 in the central region L1.
[0192] exist Figure 6 In the embodiment shown, the third circumferential groove 4 and the fourth circumferential groove 19, together with the first circumferential groove 2 and the second circumferential groove 3, define the first circumferential rib 9, the second circumferential rib 10 and the third circumferential rib 20 in the central region L1.
[0193] exist Figure 1-5 In the embodiment shown, the first circumferential rib 9 is located between the first circumferential groove 2 and the third circumferential groove 4; the second circumferential rib 10 is located between the third circumferential groove 4 and the second circumferential groove 3.
[0194] exist Figure 6 In the embodiment shown, the first circumferential rib 9 is located between the third circumferential groove 4 and the fourth circumferential groove 19; the second circumferential rib 10 is located between the third circumferential groove 4 and the second circumferential groove 3; and the third circumferential rib 20 is located between the first circumferential groove 2 and the fourth circumferential groove 19.
[0195] To increase the amount of "grounding rubber" in the central region L1, thereby optimizing handling performance, noise and rolling resistance, the central region L1 and circumferential ribs 9 and 10 have a low porosity rubber ratio.
[0196] In fact, the void rubber ratio of at least one of the first circumferential rib 9 and the second circumferential rib 10, preferably both, is less than or equal to about 0.075, more preferably less than or equal to about 0.05.
[0197] Therefore, the first circumferential rib 9 and the second circumferential rib 10 may each include a plurality of third transverse grooves 11 and fourth transverse grooves 12 with limited width and / or extension range.
[0198] To avoid excessive and sudden stiffness changes between the outer tire shoulder region L2 and the central portion L1, in the first circumferential rib 9, the third lateral groove 11 preferably extends from the first circumferential groove 2 and is positioned along the extension direction of the second lateral groove 7 located in the outer tire shoulder region L2.
[0199] The orientation of the second transverse groove 11 is preferably formed at an angle α' between 75° and 90° with the equatorial plane XX.
[0200] Preferably, the third transverse groove 11 extends over up to 80% of the width of the circumferential rib 9.
[0201] More preferably, the third transverse groove 11 extends over up to 50% of the width of the circumferential rib 9.
[0202] exist Figure 4 In the embodiment shown, the third transverse groove 11 extends over up to 30% of the width of the circumferential rib 9.
[0203] The third transverse groove 11 can have a basically straight orientation.
[0204] The third transverse grooves 11 are arranged in the circumferential direction at a distance between each other, preferably between 25 mm and 80 mm.
[0205] The maximum width of the third transverse groove 11 is less than the maximum width of the first transverse grooves 5 and 6.
[0206] The width of the third transverse grooves 11 is preferably less than about 3 mm. For example, their width can be between about 1.2 and about 3 mm.
[0207] The width of the third transverse groove 11 is preferably substantially equal to the width of the second transverse groove 7.
[0208] The depth of the third transverse groove 11 may be greater than or equal to about 2 mm. Preferably, the depth of the third transverse groove 11 may be less than about 5 mm. For example, their depth may be between about 2.5 and about 4.5 mm.
[0209] The depth of the third transverse grooves 11 may not be constant along their respective extension range.
[0210] In some embodiments, for example Figure 6 In the example shown, the third trench 11 has a first portion 11A and a second portion 11B of different widths arranged continuously to each other.
[0211] like Figure 3 , Figure 5 and Figure 6 In the example shown, the first circumferential rib 9 may include multiple fifth transverse grooves 13.
[0212] In the first circumferential rib 9, the fifth transverse groove 13 preferably extends from the third circumferential groove 4.
[0213] Preferably, the fifth transverse groove 13 has a substantially straight orientation.
[0214] The fifth transverse groove 13 extends over at most 50% of the width of the circumferential rib 9, preferably over at most 30% of the width of the circumferential rib 9.
[0215] exist Figure 3 , Figure 5 and Figure 6 In the embodiment shown, the fifth transverse groove 13 extends in a direction substantially parallel to the direction of the third transverse groove 11.
[0216] The fifth transverse groove 11 is inclined at an angle α' between 75° and 90° with the equatorial plane XX.
[0217] The width of the fifth transverse groove 13 is greater than the width of the third transverse groove 11. Preferably, the width of the fifth transverse groove 13 is equal to or greater than about 3 mm.
[0218] For example, their width can be between approximately 3.5 mm and approximately 6 mm.
[0219] The depth of the fifth transverse groove 13 may be greater than or equal to about 2 mm. For example, its depth may be between about 2.5 mm and about 5 mm. The depth of the fifth transverse groove 13 may not be constant along its respective extension range.
[0220] The second circumferential rib 10 includes multiple fourth transverse grooves 12.
[0221] The fourth transverse groove 12 extends at least 50% of the width of the second circumferential rib 10.
[0222] Preferably, the fourth transverse groove 12 extends over at least 90% of the width of the second circumferential rib 10.
[0223] The fourth groove 12 preferably extends from the second circumferential groove 3 to the third circumferential groove 4, that is, it extends over the entire width of the second circumferential rib 10.
[0224] The fourth transverse groove 12 has at least one first segment 12' and at least one second segment 12 continuously positioned relative to the first segment 12'.
[0225] The first segment 12' and the second segment 12" preferably have a basically straight direction.
[0226] Preferably, the second segment 12” is tilted in the opposite direction to the first segment 12’.
[0227] To limit excessive stiffness variation of the tread belt in the axial direction, in some embodiments, for example... Figure 1-3 and Figure 4 In the example shown, the first segment 12' of the fourth groove 12 extends substantially along the extension direction of the second transverse groove 7.
[0228] exist Figure 5 and Figure 6 In the embodiment shown, the first segment 12' of the fourth transverse groove 12 extends in a direction that is substantially parallel to the extension direction of the second transverse groove 7, but offset in the circumferential direction.
[0229] In some embodiments, for example Figure 1-3 , Figure 4 and Figure 5 In the example shown, the second segment 12” has a first part 12”A and a second part 12”B that are arranged continuously to each other with different widths.
[0230] The width of the fourth transverse groove 12 is preferably equal to or greater than about 1 mm.
[0231] The width of the fourth transverse groove 12 is preferably equal to or less than about 6 mm.
[0232] The depth of the fourth transverse groove 12 may be greater than or equal to about 2 mm. For example, their depth may be between about 2.5 mm and about 5 mm.
[0233] The depth of the fourth transverse groove 12 is not constant along its corresponding extension range.
[0234] As in Figure 5 In the embodiment shown, the second circumferential rib 10 may have a plurality of sixth transverse grooves 22.
[0235] The sixth transverse groove 22 preferably extends from the second circumference toward the groove 3.
[0236] The sixth transverse groove 22 preferably has a basically straight direction.
[0237] Preferably, the sixth transverse groove 22 extends over a maximum of 80% of the width of the second circumferential rib 10.
[0238] The sixth transverse groove 22 preferably extends in a direction that is substantially parallel to the direction of the second segment 12” of the fourth transverse groove 12.
[0239] The width of the sixth transverse groove 22 is preferably equal to or greater than about 1 mm.
[0240] The width of the sixth transverse groove 22 is preferably equal to or less than about 6 mm.
[0241] The depth of the sixth transverse groove 22 may be greater than or equal to about 2 mm. For example, its depth may be between about 2.5 mm and about 5 mm. The depth of the sixth transverse groove 22 may be non-constant along its corresponding extension range.
[0242] In some embodiments, such as Figure 6 In the embodiment shown, the central portion L1 may have a fourth circumferential groove 19, which is positioned to define a third circumferential rib 20 between the first circumferential rib 9 and the outer shoulder region L2.
[0243] In addition, in order to maintain an appropriate amount of rubber in contact with the ground, the third circumferential rib 20 also has the characteristic of a low porosity rubber ratio.
[0244] The void rubber ratio of the third circumferential rib 20 is preferably less than or equal to about 0.09.
[0245] For this purpose, the third circumferential rib 20 includes a plurality of seventh transverse grooves 14 having a limited extension range and / or width.
[0246] Preferably, the seventh transverse groove 14 extends over at least 70%, more preferably at least 90%, of the width of the third circumferential rib 20.
[0247] exist Figure 6 In the embodiment shown, the seventh groove 14 extends from the first circumferential groove 2 to the fourth circumferential groove 19, that is, they extend over the entire width of the third circumferential rib 20.
[0248] To reduce excessive stiffness variation in the axial direction in the tread band, the seventh groove 14 preferably extends from the first circumference toward the groove 2 and is positioned substantially along the extension direction of the second lateral groove 7.
[0249] The orientation of the seventh groove 14 is preferably formed with the equatorial plane XX at an angle α' between 75° and 90°.
[0250] The width of the seventh groove 14 is preferably equal to or greater than about 1 mm.
[0251] The width of the seventh groove 14 is preferably equal to or less than about 6 mm.
[0252] The depth of the seventh transverse groove 14 can be greater than or equal to about 2 mm. For example, its depth can be between about 2.5 mm and about 5 mm. The depth of the seventh groove 14 can be non-constant along its corresponding extension range.
[0253] The seventh groove 14 preferably has a first part 14A and a second part 14B of different widths that are arranged continuously to each other.
[0254] Various modifications can be made to the embodiments described in detail herein, but these modifications do not exceed the scope of the invention as defined by the following claims.
Claims
1. A car tire (100), the car tire having a tread strip (1) including a central region (L1) extending across the equatorial plane (XX) of the car tire, an outer shoulder region (L2) positioned toward the outer side of the car tire and an inner shoulder region (L3) positioned toward the inner side of the car tire. A first circumferential groove (2) axially defines the outer shoulder region (L2) relative to the central region (L1) and a second circumferential groove (3) axially defines the inner shoulder region (L3) relative to the central region (L1); The width of the outer tire shoulder region (L2) is greater than the width of the inner tire shoulder region (L3); The outer shoulder area (L2) and the inner shoulder area (L3) include a plurality of first lateral grooves (5, 6), each first lateral groove having a first end substantially located at the corresponding edge of the tread band (1), each first lateral groove having a maximum width greater than or equal to 3 mm, and an extension range at least equal to 50% of the width of the shoulder area in which the first lateral groove is located. in, The outer shoulder area (L2) includes a plurality of second lateral grooves (7) extending from the first circumference toward the groove (2); The width of the second transverse groove (7) is smaller than the width of the first transverse groove (5), and it has a reverse inclined direction relative to the first transverse groove (5); The central region (L1) includes a first circumferential rib and a second circumferential rib (9, 10) separated by a third circumferential groove (4). The void rubber ratio of the first circumferential rib and the second circumferential rib (9, 10) is equal to or less than 0.
09.
2. The automobile tire (100) according to claim 1, characterized in that, The first circumferential rib (9) includes a plurality of third transverse grooves (11), which extend from the first circumferential groove (2) and are positioned along the extension direction of the second transverse groove (7).
3. The automobile tire (100) according to claim 2, characterized in that, The extension range of the third transverse groove (11) is equal to or less than 80% of the width of the first circumferential rib (9).
4. The automobile tire (100) according to any one of claims 1 to 3, characterized in that, The second circumferential rib (10) includes a plurality of fourth transverse grooves (12).
5. The automobile tire (100) according to claim 4, characterized in that, The extension range of the fourth transverse groove (12) is equal to or greater than 50% of the width of the second circumferential rib (10).
6. The automobile tire (100) according to any one of claims 1 to 3, characterized in that, The second transverse groove (7) is inclined relative to the direction parallel to the equatorial plane (XX) to form an angle (α') greater than 75°.
7. The automobile tire (100) according to any one of claims 1 to 3, characterized in that, The extension range of the second lateral groove (7) is equal to or less than 90% of the width of the outer tire shoulder area (L2).
8. The automobile tire (100) according to any one of claims 1 to 3, characterized in that, The second transverse groove (7) has no intersection with the first transverse groove (5).
9. The automobile tire (100) according to any one of claims 1 to 3, characterized in that, In the outer tire shoulder region (L2), the extension range of the second lateral groove (7) and the first lateral groove (5) has a segment located in a common circumferential annular portion (S), the width of which is at least 1 / 5 of the width of the outer tire shoulder region (L2).
10. The automobile tire (100) according to any one of claims 1 to 3, characterized in that, In the outer tire shoulder region (L2), the extension range of the second lateral groove (7) and the first lateral groove (5) has a segment located in a common circumferential annular portion (S), the width of which is at most equal to 2 / 5 of the width of the outer tire shoulder region (L2).
11. The automobile tire (100) according to claim 2 or 3, characterized in that, The extension range of the third transverse groove (11) is equal to or less than 50% of the width of the first circumferential rib (9).
12. The automobile tire (100) according to claim 4, characterized in that, The fourth transverse groove (12) has at least one first segment (12') and at least one second segment (12”) continuously positioned relative to the first segment (12'), the second segment (12”) being inclined in the opposite direction relative to the first segment (12').
13. The automobile tire (100) according to claim 12, characterized in that, The first segment (12') extends from the third circumference toward the groove (4).
14. The automobile tire (100) according to claim 12, characterized in that, The first segment (12') extends to be positioned along the extension direction of the second transverse groove (7).
15. The automobile tire (100) according to claim 12, characterized in that, The second segment (12”) extends over at least 50% of the total extension of the fourth transverse groove (12).
16. The automobile tire (100) according to claim 12, characterized in that, The first segment (12') extends over at least 20% of the total extension range of the fourth transverse groove (12).
17. The automobile tire (100) according to claim 12, characterized in that, The second segment (12”) has a first part (12”A) with a width equal to or greater than 3 mm.
18. The automobile tire (100) according to claim 17, characterized in that, The second segment (12”) has a second portion (12”B) with a width smaller than that of the first portion (12”A).
19. The automobile tire (100) according to any one of claims 1 to 3, characterized in that, The outer tire shoulder area (L2) includes a plurality of longitudinal grooves (15) having a generally circumferential orientation.
20. The automobile tire (100) according to claim 19, characterized in that, The longitudinal groove (15) intersects with at least some of the first transverse grooves (5).
21. The automobile tire (100) according to any one of claims 2 to 3, characterized in that, The void rubber ratio of the first circumferential rib (9) is formed only by the third transverse groove (11).
22. The automobile tire (100) according to any one of claims 2 to 3, characterized in that, The first circumferential rib (9) includes a plurality of fifth transverse grooves (13).
23. The automobile tire (100) according to claim 22, characterized in that, The extension range of the fifth transverse groove (13) is equal to or less than 50% of the width of the first circumferential rib (9).
24. The automobile tire (100) according to claim 22, characterized in that, The width of the fifth transverse groove (13) is greater than the width of the third transverse groove (11).
25. The automobile tire (100) according to any one of claims 1 to 3, characterized in that, The central region (L1) includes a third circumferential rib (20), which is separated from the first circumferential rib (9) by a fourth circumferential groove (19).
26. The automobile tire (100) according to claim 25, characterized in that, The void rubber ratio of the third circumferential rib (20) is equal to or less than 0.
09.
27. The automobile tire (100) according to claim 25, characterized in that, The third circumferential rib (20) includes a plurality of seventh transverse grooves (14).
28. The automobile tire (100) according to claim 27, characterized in that, The extension range of the seventh transverse groove (14) is equal to or greater than 60% of the width of the third circumferential rib (20).
29. The automobile tire (100) according to claim 27, characterized in that, The seventh transverse groove (14) extends from the first circumferential groove (2) and is positioned along the extension direction of the second transverse groove (7).
30. The automobile tire (100) according to any one of claims 1 to 3, characterized in that, The first transverse grooves (5, 6) have a substantially straight orientation.
31. The automobile tire (100) according to any one of claims 1 to 3, characterized in that, The second transverse groove (7) has a substantially straight orientation.
32. The automobile tire (100) according to any one of claims 1 to 3, characterized in that, The void rubber ratio of the inner shoulder region (L3) is formed only by the first lateral groove (6) of the inner shoulder region.
33. The automobile tire (100) according to any one of claims 1 to 3, characterized in that, In the inner shoulder region (L3), the extension range of the first lateral groove (6) is equal to or less than 90% of the width of the inner shoulder region (L3).
34. The automobile tire (100) according to any one of claims 1 to 3, characterized in that, The number of the first lateral grooves (5) in the outer shoulder region (L2) is less than the number of the first lateral grooves (6) in the inner shoulder region (L3).
35. The automobile tire (100) according to claim 34, characterized in that, The number of first lateral grooves in the inner shoulder region (L3) is approximately twice the number of first lateral grooves in the outer shoulder region (L2).