Low rolling resistance pneumatic tire

Abstract

The invention relates to a low-rolling-resistance pneumatic tire, and the low-rolling-resistance pneumatic tire is provided with a tread, and a circumferential groove is formed in the tread; each circumferential groove is provided with a notch groove, a thin groove and a water storage groove which are sequentially formed from the tire surface to the interior of the tire body; the maximum widths of the notch groove, the thin groove and the water storage tank in the axial direction of the tire are marked as W1, W2 and W3 respectively, and at least W2lt is met; w1 and W2lt; w3. According to the low-rolling-resistance pneumatic tire, the three-section groove design of the notches, the thin grooves and the water storage grooves is adopted in the radial direction of the tire through the central circumferential groove, and parameters such as the width, the depth and the repeated spacing are reasonably configured for the three-section groove design, so that it is ensured that the tire has excellent wet land performance, low-rolling-resistance performance and stone clamping prevention performance.

Description

Technical Field

[0001] The present invention relates to the technical field of tires, and particularly to a low rolling resistance pneumatic tire. Background Art

[0002] Typical tires for buses or trucks will encounter various road conditions during their use (e.g., dry / wet roads, roads with gravel, etc.). Different road conditions have different requirements for tire performance. To match different usage environments of the tires, tire tread patterns are designed with different characteristics according to different performance requirements of the tires. For example, to improve the wet performance of pneumatic tires, the width of circumferential grooves can be increased. However, simply increasing the width of circumferential grooves will reduce the stiffness of the tread surface. This reduction in stiffness may have an adverse impact on the low rolling resistance performance, wear, and other performances of the tires, and at the same time, it will increase the risk of stone trapping in the tires. Therefore, the wet performance, rolling resistance, stone trapping prevention, and other performances of tires often restrict each other. Therefore, manufacturing a tire that兼顾wet performance, low rolling resistance performance, and stone trapping prevention is a technical problem in the current tire industry.

[0003] To solve the above background problems, more and more companies have carried out novel feature designs on the grooves of tires to improve tire performance. Inventors of companies such as Goodyear have set stability grooves in the circumferential direction of the tires to improve the cornering stiffness of the tires and reduce crack initiation at the bottom of the grooves; inventors of companies such as Michelin have designed hidden grooves and partially hidden grooves in the circumferential direction of the tires to balance the wet performance and wear performance of the tires. The above existing tire designs do not balance multiple performances such as wet performance, low rolling resistance performance, handling performance, and stone trapping prevention of the tires. To solve the above technical problems, the present invention provides a pneumatic tire. By adopting a three-stage groove design in the radial direction of the tire through a central groove, and at the same time, the cuts of the three-stage grooves are designed in a gradual change on the circumferential surface of the tire, so as to ensure that the tire has stone trapping prevention, low rolling resistance, and excellent handling performance while improving the wet performance of the tire. Summary of the Invention

[0004] To balance multiple performances of the tire, the present invention provides a low rolling resistance pneumatic tire.

[0005] The present application provides a low rolling resistance pneumatic tire, which is characterized in that it has a tread surface, and circumferential grooves are formed on the tread surface; a plurality of circumferential grooves have cut grooves, fine grooves, and water storage grooves formed successively from the tread surface to the inside of the tire body; The maximum widths of the cut grooves, the fine grooves, and the water storage grooves along the axial direction of the tire are respectively denoted as W1, W2, and W3, and at least W2 < W1 and W2 < W3 are satisfied.

[0006] Preferably, the widths of the cut grooves, the fine grooves, and the water storage grooves satisfy: 4 mm ≤ W1 ≤ 20 mm, and 2.5 mm ≤ W3 ≤ 16 mm.

[0007] Preferably, the incision groove has a periodically gradually changing opening width along the circumferential direction on the tread surface, wherein the periodic spacing L satisfies 0.5PL≤L≤4PL; Preferably, 1.0PL≤L≤2.2PL.

[0008] Preferably, the width of the cutout groove at the widest point and the narrowest point are respectively recorded as W1max and W1min, both of which satisfy 0.3mm≤(W1max-W1min) / 2≤6mm; Preferably, 1.5 mm ≤ (W1max - W1min) / 2 ≤ 5 mm.

[0009] Preferably, the cutout groove forms a pair of opposite cutout side walls, and a non-zero angle α is formed between the opposite cutout side walls, 20°≤α≤120°; Preferably, 42.5°≤α≤85° Preferably, the width of the fine groove satisfies: 0.5mm≤W2≤3.0mm.

[0010] Preferably, the water storage tank has opposite water storage walls, the two opposite water storage walls form an angle δ with the inside of the tire body, and the intersection of the water storage walls occurs inside the tread, wherein 30°≤δ≤125°.

[0011] Preferably, the depths of the cutout groove, the fine groove and the water storage tank are denoted as h1, h2, and h3, respectively; wherein, h1, h2, and h3 satisfy: h1+h2+h3=H, 0.08H≤h1≤0.41H, 0.15H≤h2≤0.55H, 0.25H≤h3≤0.60H; wherein, H is the total depth of the circumferential groove.

[0012] Preferably, the water tank bottom of the water tank has a stone ejector that is higher than the water tank bottom; Preferably, the width W4 of the slingshot satisfies 1mm≤W4≤0.4W3; the depth W4 of the slingshot satisfies 1mm≤h4≤0.7h3.

[0013] Preferably, it also includes transverse grooves formed on the tread, which extend from the circumferential groove to the tread on both sides of the circumferential groove; different transverse grooves are staggered or connected on the tread; preferably, the transverse grooves are inclined along the circumference of the tire.

[0014] The low rolling resistance pneumatic tire of the present application utilizes a three-stage groove design of a central circumferential groove in the radial direction of the tire, including a cut, a fine groove and a water storage tank. By rationally configuring parameters such as width, depth and repeatability spacing of the three-stage groove design, and combining the gradual width design of the cut of the three-stage groove on the circumferential surface of the tire, it is ensured that the tire has excellent wetland performance, low rolling resistance performance and anti-stone pinching performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Schematic diagram of the development of the tread 11 of the low rolling resistance pneumatic tire of the present application; Figure 2 Schematic diagram of a radial section of a main groove 121 of the low rolling resistance pneumatic tire of the present application; Figure 3 Schematic diagram of the circumferential development of the notch groove 211 of the low rolling resistance pneumatic tire of the present application; Figure 4 Schematic diagram of a radial section of the tread 11 of the low rolling resistance pneumatic tire of the present application; Figure 5 Schematic diagram of other gradual changes in the tread 11 of the low rolling resistance pneumatic tire of the present application; Figure 6 It is a schematic diagram of another cross-sectional embodiment of the tread 11 of the low rolling resistance pneumatic tire of the present application.

[0016] In the figure: 1: tire; 11: tread; 12: circumferential groove; 121: main groove; 122: shoulder groove; 13: transverse groove; 14: pattern block; 211: cut groove; 212: fine groove; 213: water storage tank; 215: stone ejector; 216: water storage tank bottom; 217: water storage wall; 218: middle wall; 219: cut side wall. DETAILED DESCRIPTION

[0017] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. In this specification, the size ratios in the drawings do not represent the actual size ratios, but are only used to reflect the relative position relationship and connection relationship between the components. Components with the same name or the same number represent similar or identical structures and are only for illustrative purposes.

[0018] The following terms are applicable to the technical solutions described in this application.

[0019] Tire circumferential direction: refers to the direction along the circumference of the tire, that is, the direction around the tire's rotation axis; Tire axial direction: refers to the direction along the tire's rotation axis, also known as the tire width direction; Tire radial direction: refers to the direction along the radius of the tire circumference, that is, the direction of the tread groove depth; in the radial direction, the direction from a point on the tire circumferential surface to the tire rotation center is defined as the positive radial direction, and the opposite direction is the negative radial direction; Tread X direction: the tire axial direction mentioned above; Tread Y direction: the direction corresponding to the tire circumference after the tread is flattened; Radial section: The tire cross section cut along the tire axial direction and a certain radial plane; Circumferential groove: A groove formed on the tread of a tire and extending along the circumferential direction of the tire; Cross knife groove: A groove formed on the tread of a tire and extending along the axial direction of the tire with a relatively narrow width; Pattern pitch: The distance between adjacent cross knife grooves in the circumferential direction of the tire, denoted as PL.

[0020] Figure 1 It is a schematic structural view of the low rolling resistance pneumatic tire of the present application. This type of low rolling resistance pneumatic tire is mainly used for passenger cars and trucks. The tire 1 has a tread 11, and a circumferential groove 12 and a cross knife groove 13 are formed on the tread 11. The tread 11 is divided into different tread blocks 14 by the circumferential groove 12 and the cross knife groove 13.

[0021] In Figure 1 In the illustrated embodiment, the circumferential groove 12 is further divided into shoulder grooves 122 that are closer to each side shoulder of the tread 11. Since the shoulders are located on both sides of the tread, the shoulder grooves 122 are formed on both sides of the tread 11, and there can be no less than one shoulder groove 122 on each side. No less than one main groove 121 is formed on the tread between the shoulder grooves 122 on both sides.

[0022] The cross knife groove 13 extends from the circumferential groove 12 to the tread on both sides of the circumferential groove 12. Different cross knife grooves 13 can be staggered or connected on the tread. The cross knife groove 13 is preferably inclined in the circumferential direction of the tire as a whole, that is, it is not at a right angle to the circumferential groove 12 as a whole, but forms an acute angle, and the orientation of the acute angle is related to the driving direction of the tire.

[0023] In order to improve the comprehensive performance of the tire, the present application mainly redesigned the circumferential groove 12, especially the main groove 121 therein.

[0024] Figure 2 It is a schematic view of the radial section of the main groove 121. The main groove 121 has a three-section groove structure that penetrates into the carcass below the tread in the positive radial direction. Specifically, the main groove 121 successively forms a cut groove 211, a fine groove 212, and a water storage groove 213 from the tread into the carcass interior. The maximum widths of the cut groove 211, the fine groove 212, and the water storage groove 213 along the axial direction of the tire are respectively denoted as W1, W2, and W3, and at least W2 < W1 and W2 < W3 are satisfied. In other words, the main groove 121 is in a dumbbell shape with wide ends and a narrow middle on the radial section.

[0025] The notch groove 211 is provided to prevent the groove edge curling effect when the tire turns, and at the same time has a certain water storage function to improve the tire's handling performance and wetland performance; when the tire is loaded, the relative walls 218 of the fine groove 212 contact each other, providing mutual deformation support, reducing strain, and reducing rolling resistance; while ensuring the tire's handling performance and rolling resistance performance, the water storage tank 213 is provided to provide additional water storage volume to ensure the tire's wetland performance throughout its life cycle.

[0026] Among them, 4mm≤W1≤20mm, in order to take into account the dry and wet braking and handling performance of the tire, it is preferably 4mm≤W1≤10mm; 0.5mm≤W2≤3mm, in order to take into account the rolling resistance performance of the tire and the service life of the mold, it is preferably 1mm≤W2≤2.2mm; 2.5mm≤W3≤16mm, in order to take into account the wet performance of the tire, reduce the difficulty of vulcanization demolding, and avoid stress concentration at the bottom of the water tank causing tearing at the groove bottom, it is preferably 5mm≤W3≤10mm.

[0027] Under the condition that the depth of the cut groove 211, the fine groove 212 and the water storage tank 213 remain unchanged (the length remains constant), when W1 is less than 4mm, W1 is too small. When the tire is braking and maneuvering on dry land, it is very easy to produce curling deformation at the edge of the circumferential groove, reducing the effective contact area, which is not conducive to the tire's dry land braking and maneuvering performance; at the same time, W1 is too small, the groove volume of the cut groove area is reduced, and during wet land braking and maneuvering, this area cannot effectively store water and quickly drain water, the risk of water drifting of the tire increases, affecting wet land performance, and also causing traffic safety hazards; when W1 is greater than 20mm, W1 is too large, resulting in the rigidity of the middle tread pattern. The ground contact pressure distribution of truck and bus tires is usually high in the middle and low in the shoulder. When the tread block stiffness in the middle area of ​​the high stress zone is too weak, it will first cause the tire to produce greater compression deformation of the tread block during normal driving, thereby generating greater energy loss, which is not conducive to rolling resistance performance; in addition, too weak tread block stiffness in the middle will cause the tire to easily undergo greater shear and bending deformation when driving or turning, which is not conducive to the tire's dry and wet braking and handling performance; at the same time, the tread pattern stiffness in the middle is too weak, the stress strain of the tire when it is grounded increases, and the tread slippage will also increase, resulting in abnormal wear in the middle of the tire. Moreover, the fine groove (212) will deform during the tire rolling process, thereby causing self-contact, that is, self-contact occurs between the two side walls, and this self-contact process in turn limits the deformation of the rubber block of the tire, thereby achieving the effect of reducing rolling resistance.

[0028] In order to further optimize the performance of the tire, the width of the cut groove 211 in the circumferential direction of the tread surface is designed in a periodic gradual variation, wherein the periodic spacing is 0.5PL≤L≤4PL, and preferably 1.0PL≤L≤2.2PL. The width of the cut groove 211 in the circumferential direction of the tread surface is designed in a gradual variation, which not only takes into account the low rolling resistance performance of the tire, but also optimizes the wet performance and anti-stone pinching performance of the tire. Its mechanism of action is as follows: Compared with the equal width design, the gradient width design can provide effective gripping of the groove boundary in both the circumferential and axial directions of the tire, thereby improving the tire's wet braking performance while ensuring the tire's wet handling performance; at the same time, in terms of anti-stone pinching performance, the stone-throwing mechanism of the equal width design is to generate an oblique upward force perpendicular to the plane of the cut sidewall, and the direction of the force is single, basically parallel to the radial section of the tire; while the gradient groove design, because the cut sidewall plane generated is a curved surface, it can generate multi-directional stone-throwing force, and at the same time, through the joint action of the groove walls on both sides of the cut, it can generate a counterclockwise or clockwise torque with the tire radial as the rotation center line, which can significantly increase the probability of stone-throwing, thereby improving the tire's anti-stone pinching performance; in terms of rolling resistance performance, compared with the equal width scheme, the gradient design is only an alternating change of width and narrowness, and the distribution is optimized by a reasonable width-narrow ratio, which will not affect the actual rubber block volume, so its rolling resistance performance is not worse than that of the equal width design.

[0029] like Figure 3 As shown, the width of the incision groove 211 at the widest and narrowest parts (the axial distance of the groove along the tire) is recorded as W1max and W1min respectively, and the following relationship exists between the two: 0.3mm≤(W1max-W1min) / 2≤6mm, and preferably 1.5mm≤(W1max-W1min) / 2≤5mm. When (W1max-W1min) / 2>6mm, (W1max-W1min) / 2 is too large, so that the force of the pattern block in the transition area is uneven, resulting in a certain degree of eccentric wear of the tire at the narrowest part of the incision, and easy stone clamping at the widest part of the incision.

[0030] like Figure 3 As shown, the transition arc connecting the widest and narrowest parts of the cut groove 211 is respectively recorded as Re and Rc, and the two have the following relationship: 0.5mm≤Rc≤Re≤6.5mm, and preferably 2.0mm≤Rc≤Re≤4.6mm. When Rc≤Re<0.5mm, stress concentration is prone to occur in the transition area from the widest part to the narrowest part of the cut, affecting the life of the tire. When Re≥Rc>6.5mm, the transition area from the widest part to the narrowest part of the cut will be very large, affecting the appearance of the tread pattern.

[0031] The width of the cutout groove 211 on the tread surface is designed to be gradual, and the top view of the central circumferential groove is not limited to Figure 1As shown, it can also be replaced by Figure 5 The cut groove 211 forms a pair of opposite cut sidewalls 219 on the tread pattern, and the opposite cut sidewalls 219 form a non-zero angle α. The intersection of the cut sidewalls 219 occurs inside the tread, wherein 20°≤α≤120°, and preferably 42.5°≤α≤85°, which can effectively increase the edge pressure on the tread. The cross-sectional shape of the cut groove 211 in the radial direction of the tire is not limited to Figure 3 The triangle shown can also be replaced by Figure 5 The polygon shown.

[0032] The fine groove 212 is a channel of substantially equal width, defined by substantially parallel intermediate walls 218. When the spacing W2 between the relative walls is greater than 3.0 mm, W2 is too large, and the fine groove does not sufficiently strengthen the pattern block. The pattern block cannot contact itself during the rolling process of the tire, resulting in insufficient overall rigidity of the pattern block, which easily increases the rolling resistance of the tire. At the same time, the increase in the volume of the fine groove will reduce the volume of the pattern block, which is not conducive to the wear performance of the tire.

[0033] When the axial width W3 of the water tank 213 is greater than 16 mm, it is difficult to demould the tire during tire manufacturing, and the pattern blocks are easily torn. When W3 is less than 2.5 mm, the water storage volume of the water tank is insufficient, which affects the wet performance of the tire.

[0034] The water storage tank 213 forms a pair of water storage walls 217 between adjacent tread blocks. The water storage wall 217 is connected to the water storage tank bottom 216 through an arc. The radius Ra of the arc is between 0.4 mm and 5 mm, and preferably 1.2 mm ≤ Ra ≤ 2.5 mm. When Ra>5 mm, the water storage capacity and drainage capacity of the tire on a slippery road surface decrease, which damages the wetland performance of the tire. When the tire is worn to a certain extent, it cannot be guaranteed that the tire has sufficient wetland traction. When Ra<0.4 mm, during the driving process of the tire, stress concentration is likely to occur at the arc connecting the water storage wall 217 of the water storage tank and the bottom 216 of the water storage tank, which affects the service life of the tire. The relative water storage wall 217 forms a non-zero angle δ in the axial direction of the tire, and the intersection of the relative walls occurs inside the tread, where 30°≤δ≤125°. When δ>125°, demoulding is difficult during the tire manufacturing process, which is likely to cause tearing of the tread block.

[0035] The cross-sectional shape of the water storage tank 213 in the tire radial direction is not limited to Figure 3 As shown in , it can also be replaced by Figure 6 The cross-sectional shape shown.

[0036] We conducted experimental research on the above design scheme, and the experimental scheme and test results are shown in Table 1. Among them, the rolling resistance index is obtained by indoor rolling resistance test machine test, and the wet grip index, anti-stone pinching index and anti-eccentric wear index are obtained by FEA simulation.

[0037] Table 1

[0038] Note: The larger the above index is, the smaller the rolling resistance is, and the better the low rolling resistance performance is; the greater the wet grip is, the better the wet performance is; the stronger the stone pinching resistance is, the better the stone pinching resistance is. It can be found from Table 1 that when the main groove is designed with only a single element, the tire can only guarantee a single performance; in order to ensure the low rolling resistance, wetland performance and stone pinching resistance of the tire at the same time, the main groove adopts a three-stage design (Scheme 5); after further research, it is found that the incision groove 211 adopts a gradual width design to a certain extent (Scheme 10), and the maximum width and minimum width of the incision groove 212 are reasonably designed, which is conducive to further improving the low rolling resistance performance, wetland performance and stone pinching resistance of the tire, while ensuring the tire's anti-eccentric wear performance.

[0039] As shown in the figure, the tread has a tread depth H, and the depths of the cut, fine groove and water tank (the distance of the groove in the radial direction of the tire) are recorded as h1, h2, and h3 respectively. Among them, there is the following relationship between H and h1, h2, and h3: h1+h2+h3=H. The reasonable distribution of the cut depth h1, the fine groove depth h2, and the water tank depth h3 can ensure that the dry land, wet land, rolling resistance and other performances are taken into account at the same time. In order to ensure the rolling resistance performance while ensuring the dry and wet land performance, the distribution ranges of h1 and h2 are 0.08H≤h1≤0.41H and 0.15H≤h2≤0.55H respectively; in order to further improve the wet braking and handling performance in the middle and late stages of tire wear, it is preferred to obtain 0.15H≤h1≤0.35H, 0.27H≤h2≤0.42H, and 0.25H≤h3≤0.60H.

[0040] When the width of the cutout groove 211, the fine groove 212 and the water storage tank 213 remain unchanged (the length remains constant), when h2 is less than 0.15H, h2 is too small, which weakens the role of connecting and strengthening the cutout and the water storage tank, and reduces the contact area of ​​the relative sidewalls during the rolling process of the tire, reducing the self-contact effect of adjacent pattern blocks during compression deformation, resulting in a weakening of the overall rigidity of the pattern blocks, which is detrimental to the rolling resistance performance of the tire. When h2 is greater than 0.55H, the cutout and the water storage tank are too small, the volume of the entire circumferential groove is reduced, and the wet performance of the tire is reduced.

[0041] We conducted experimental research on the above design scheme, and the experimental scheme and test results are shown in Table 2. Among them, the rolling resistance index is obtained by indoor rolling resistance test machine test, and the wet grip index and anti-stone pinching index are obtained by FEA simulation.

[0042] Table 2

[0043] Note: The larger the above index is, the smaller the rolling resistance is, and the better the low rolling resistance performance is; the greater the wet grip is, the better the wet performance is; the stronger the stone pinching resistance is, the better the stone pinching resistance is. It can be seen from Table 2 that to ensure the low rolling resistance performance, wetland performance and stone pinching resistance performance of the tire, it is necessary to reasonably design the depth of the cut groove 212, the fine groove 213 and the water storage tank 214 of the three-stage groove (Scheme 18). Increasing the depth of the middle fine groove 212 to a certain extent is conducive to improving the low rolling resistance performance of the tire (Scheme 19, Scheme 20).

[0044] In order to enhance the anti-stone performance of tires in the later stage of tire wear, Figure 4 As shown, a stone ejector 215 is provided in the tire water storage tank 213, and the width of the stone ejector (the axial distance of the groove along the tire) is recorded as W4, where 1mm≤W4≤0.4W3; the depth of the stone ejector (the radial distance of the groove along the tire) is recorded as h4, where 1mm≤h4≤0.7h3. When the width of the stone ejector W4 is less than 1mm and the depth h4 is less than 1mm, the stone ejector cannot prevent stones from being clamped in the later stage of tire wear. When the width of the stone ejector W4 is greater than 0.4W3 or the depth h4 is greater than 0.7h3, the stone ejector greatly reduces the water storage volume of the water storage tank, thereby reducing the wetland performance of the tire.

[0045] We conducted experimental research on the above design scheme, and the experimental scheme and test results are shown in Table 3. Among them, the rolling resistance index is obtained by indoor rolling resistance test machine test, and the wet grip index, anti-stone pinching index and anti-eccentric wear index are obtained by FEA simulation.

[0046] Table 3

[0047] Note: ①. The larger the above index is, the smaller the rolling resistance is, and the better the low rolling resistance performance is; the greater the wet grip is, the better the wet grip performance is; the stronger the anti-stone pinching ability is, the better the anti-stone pinching performance is; the stronger the anti-eccentric wear ability is, the better the anti-eccentric wear performance is. ②. The width of the middle fine groove is 1mm and the depth is 5mm. It can be found from Table 3 that a reasonable design of the cut groove 212 cycle is conducive to improving the rolling resistance performance, wet grip performance and anti-stone pinching performance of the tire while ensuring the anti-eccentric wear performance of the tire. Adding a groove bottom stone ejector 215 is conducive to improving the anti-stone pinching performance of the tire, especially the anti-stone pinching performance in the later stage of tire wear.

[0048] The above content only describes the preferred implementation mode of the present invention, and does not limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solution of the present invention by ordinary technicians in this field should fall within the protection scope determined by the claims of the present invention.

Claims

1. A low rolling resistance pneumatic tire, characterized in that: It has a tread (11), and circumferential grooves (12) are formed on the tread (11); several of the circumferential grooves (12) have a cut groove (211), a fine groove (212) and a water storage groove (213) formed successively from the tread towards the inside of the carcass; The maximum widths of the cut groove (211), the fine groove (212) and the water storage groove (213) along the tire axis are respectively denoted as W1, W2 and W3, and at least satisfy W2 < W1, W2 < W3 and 0.5 mm ≤ W2 ≤ 3 mm.

2. The low rolling resistance pneumatic tire according to claim 1, characterized in that: The widths of the cut groove (211), the fine groove (212) and the water storage groove (213) satisfy: 4 mm ≤ W1 ≤ 20 mm, and 2.5 mm ≤ W3 ≤ 16 mm.

3. The low rolling resistance pneumatic tire according to claim 1, characterized in that: The cut groove (211) has a periodically varying opening width along the circumferential direction on the surface of the tread (11), and the periodic pitch L satisfies 0.5PL ≤ L ≤ 4PL; Preferably, 1.0PL ≤ L ≤ 2.2PL.

4. The low rolling resistance pneumatic tire according to claim 1, wherein: The widths of the cut groove (211) at the widest and narrowest points are respectively denoted as W1max and W1min, and the two satisfy 0.3 mm ≤ (W1max - W1min) / 2 ≤ 6 mm; Preferably, 1.5 mm ≤ (W1max - W1min) / 2 ≤ 5 mm.

5. The low rolling resistance pneumatic tire according to claim 1, wherein: The cut groove (211) forms a pair of opposite cut side walls (219), and a non-zero angle α is formed between the opposite cut side walls (219), 20° ≤ α ≤ 120°; Preferably, 42.5° ≤ α ≤ 85°.

6. The low rolling resistance pneumatic tire according to claim 1, wherein: The water storage groove (213) has opposite water storage wall surfaces (217), and the two opposite water storage wall surfaces (217) form an angle δ towards the inside of the carcass, and the intersection part of the water storage wall surfaces (217) occurs inside the tread, where 30° ≤ δ ≤ 125°.

7. The low rolling resistance pneumatic tire according to claim 1, wherein: The depths of the cut groove (211), the fine groove (212) and the water storage groove (213) are respectively denoted as h1, h2, h3; among them, h1, h2, h3 satisfy: h1 + h2 + h3 = H, 0.08H ≤ h1 ≤ 0.41H, 0.15H ≤ h2 ≤ 0.55H, 0.25H ≤ h3 ≤ 0.60H; where H is the total depth of the circumferential groove (12).

8. The low rolling resistance pneumatic tire according to claim 8, wherein: The water storage bottom (216) of the water storage groove (213) has a stone ejector (215) that is higher than the water storage bottom (216).

9. The low rolling resistance pneumatic tire according to claim 8, characterized in that: The width W4 of the stone ejector (215) satisfies 1 mm ≤ W4 ≤ 0.4W3; the depth h4 of the stone ejector (215) satisfies 1 mm ≤ h4 ≤ 0.7h3.

10. The low rolling resistance pneumatic tire according to claim 1, wherein: It also includes a transverse knife groove (13) formed on the tread (11), and the transverse knife groove (13) extends from the circumferential groove (12) to the tread on both sides of the circumferential groove (12); different transverse knife grooves (13) are staggered or connected on the tread (11); preferably, the transverse knife groove (13) is inclined along the tire circumference.

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