A tire design method, application, and tire for improving rolling resistance.

Abstract

This invention relates to the field of tire design technology, and more particularly to a tire design method, application, and tire for improving tire rolling resistance. The method is based on the tire's rim width Wr, and by coordinating the relationship between Wr and the tire's contact patch width Wt and height drop h, it reduces the curvature of the tire crown profile curve, thereby improving tire rolling resistance.

Description

Technical Field

[0001] This invention relates to the field of tire design technology, and in particular to a tire design method, application, and tire for improving tire rolling resistance. Background Technology

[0002] With increasingly stringent global greenhouse gas emission requirements and rising fuel costs, improving fuel efficiency is a significant challenge for automakers. Tires, as a crucial component of a vehicle, significantly contribute to overall fuel efficiency through their rolling resistance. Studies show that a 10% reduction in tire rolling resistance can decrease overall vehicle fuel consumption by 0.5% to 1.5%.

[0003] Tire rolling resistance is mainly caused by the viscoelasticity of the rubber materials that make up the tire. During tire rolling, due to the phase difference between stress and strain, hysteresis loss (mechanical energy is converted into heat energy) occurs. This hysteresis loss is the main cause of tire rolling resistance.

[0004] Rolling resistance is related to the stress, strain, material hysteresis loss, and material volume of each element of the tire rubber material. The expression for the rolling resistance of a tire in each rolling cycle is as follows:

[0005] RR=∫ V σ·ε·tanδdV

[0006] In the formula, RR represents tire rolling resistance, V is the volume of the rubber material, σ is stress, ε is strain, and δ is the phase angle difference between stress and strain. Methods to improve tire rolling resistance also focus on these aspects: reducing the volume of the rubber material, lowering stress and strain, and reducing the stress-strain phase angle difference of the material.

[0007] The shortcomings of existing solutions: Reducing rolling resistance by reducing the material volume V of the tire can be divided into reducing the depth of the tire tread grooves and reducing the thickness of the sidewall. The former has a negative impact on tire wear mileage, while the latter will inevitably weaken tire safety.

[0008] Studies have shown that the tire crown contributes 50% to 60% to the overall rolling resistance of the tire. Therefore, the curve shape of the crown is crucial to tire rolling resistance. Patent CN10505905B describes a tire outer contour design method: by designing the crown arc value, a uniform pressure distribution is achieved in the crown area, thereby reducing tire rolling resistance. However, this patent does not consider the tire's contact patch width (TW), so there is still room for improvement.

[0009] The RCOT profile design theory proposed by Yamagishi et al. suggests that reducing the curvature of the tire crown (increasing the radius of curvature and making the crown relatively flat) is beneficial to rolling resistance, but it does not provide a quantitative method for curvature design. Summary of the Invention

[0010] To address the aforementioned technical problems, the present invention aims to provide a tire design method for improving tire rolling resistance. This method is based on the tire's rim width Wr and, by coordinating the relationship between Wr and the tire's ground contact width Wt and height reduction h, reduces the curvature of the tire crown profile curve, thereby improving tire rolling resistance.

[0011] To achieve the above objectives, the present invention adopts the following technical solution:

[0012] A tire designed to improve rolling resistance includes a crown, shoulder, belt layers, sidewall, and bead. The design parameters include: crown profile width SW, rim width Wr, outer diameter OD, rim diameter D, tire section height H (half the difference between the tire's outer diameter and the rim diameter), and section height-to-width ratio (the ratio of tire section height H to section width SW multiplied by 100%). Other design parameters include tire contact patch width Wt, arc height h, crown radius Rc, crown radius Rm, outer shoulder arc radius Rso, and inner shoulder arc radius Rsi.

[0013] Wt=Wr·a, a=0.95~1.05;

[0014]

[0015] The choice for b is as follows:

[0016] 1) Cross-sectional height-to-width ratio ≤ 35, b = 3.08~3.22,

[0017] 2) Cross-sectional height-to-width ratio 40–50, b = 2.81–3.01,

[0018] 3) The cross-sectional height-to-width ratio is 55–60, and b = 2.57–2.79.

[0019] 4) The aspect ratio of the cross-section is ≥65, and b = 2.35~2.55;

[0020] Rc=Wr·b·c, c=1.2~2.0;

[0021] Rm=Wr·b·d, d=0.35~0.65;

[0022] Rso = 12~20;

[0023] Rsi = Rso·(1.1~1.3).

[0024] Preferably, a = 0.96–1.02; c = 1.30–1.80; d = 0.45–0.60; Rso = 15–20.

[0025] Preferably, the choice of b is as follows:

[0026] 1) Cross-sectional height-to-width ratio ≤ 35, b = 3.10~3.20,

[0027] 2) The cross-sectional height-to-width ratio is 40–50, and b = 2.85–2.95.

[0028] 3) The cross-sectional height-to-width ratio is 55–60, and b = 2.60–2.76.

[0029] 4) The cross-sectional height-to-width ratio is ≥65, and b = 2.40~2.50.

[0030] Furthermore, this invention also discloses a tire design method for improving tire rolling resistance. The tire includes a crown, shoulder, belt layer, sidewall, and bead. The design parameters include: crown profile width SW, rim width Wr, outer diameter OD, rim diameter D, tire section height H (half the difference between the tire's outer diameter and the rim diameter), and section height-to-width ratio (the ratio of tire section height H to section width SW multiplied by 100%). The tire contact patch width Wt, arc height h, crown radius Rc, crown radius Rm, outer shoulder arc radius Rso, and inner shoulder arc radius Rsi are also provided.

[0031] Wt=Wr·a, a=0.95~1.05;

[0032]

[0033] The choice for b is as follows:

[0034] 1) Cross-sectional height-to-width ratio ≤ 35, b = 3.08~3.22,

[0035] 2) Cross-sectional height-to-width ratio 40–50, b = 2.81–3.01,

[0036] 3) The cross-sectional height-to-width ratio is 55–60, and b = 2.57–2.79.

[0037] 4) The aspect ratio of the cross-section is ≥65, and b = 2.35~2.55;

[0038] Rc=Wr·b·c, c=1.2~2.0;

[0039] Rm=Wr·b·d, d=0.35~0.65;

[0040] Rso = 12~20;

[0041] Rsi = Rso·(1.1~1.3).

[0042] Preferably, a = 0.96–1.02; c = 1.30–1.80; d = 0.45–0.60; Rso = 15–20.

[0043] Preferably, the choice of b is as follows:

[0044] 1) Cross-sectional height-to-width ratio ≤ 35, b = 3.10~3.20,

[0045] 2) The cross-sectional height-to-width ratio is 40–50, and b = 2.85–2.95.

[0046] 3) The cross-sectional height-to-width ratio is 55–60, and b = 2.60–2.70.

[0047] 4) The cross-sectional height-to-width ratio is ≥65, and b = 2.40~2.50.

[0048] Furthermore, the present invention also discloses the application of the design method in designing tires with improved rolling resistance.

[0049] Furthermore, the present invention discloses a computer device, including a memory, a processor, and a computer program stored in the memory, wherein the processor executes the computer program to implement the method.

[0050] Furthermore, the present invention discloses a computer-readable storage medium having a computer program or instructions stored thereon, which, when executed by a processor, implements the method described herein.

[0051] Furthermore, the present invention discloses a computer program product, including a computer program or instructions that, when executed by a processor, implement the method.

[0052] The design principle of this invention is as follows:

[0053] 1. Increasing the contact patch width Wt (increasing the value of a) reduces the curvature of the tire crown under the same conditions, thus reducing the bending deformation effect of the tire crown area and having a positive impact on tire rolling resistance. However, increasing Wt also increases the volume of rubber material in the tire crown, negatively affecting tire rolling resistance. When a > 1.05, the volume change contributes more to tire rolling resistance; when a < 0.95, bending deformation contributes more to tire rolling resistance. The preferred value is a = 0.95–1.05.

[0054] 2. The tire height (h) is highly sensitive to the tire's contact patch shape and pressure distribution. For different tire models, besides the rim width (Wr), the tire's section height-to-width ratio is also a design factor affecting h. Therefore, the design of the h value should consider Wr in conjunction with coefficients a and b. An excessively large h value increases the tread curvature, which is detrimental to rolling resistance; an excessively small h value, while reducing tread curvature, increases the pressure distribution at the tire shoulder, which is detrimental to tire wear performance.

[0055] 3. How to draw the Rc arc: Its center is located on the tire centerline, and an arc with radius Rc is drawn with the tire apex as the quadrant point. The coefficient c is related to the tire's ground pressure distribution. If the value of c is too large, the ground pressure on the tire shoulder will be too large, resulting in abnormal wear on the tire shoulder; conversely, if the value of c is too small, the ground pressure on the tire crown will be too large, resulting in abnormal wear on the tire crown.

[0056] 4. Method for drawing the Rm arc: Draw an arc tangent to Rc and passing through the lower endpoint of the tire shoulder height h, with a radius of Rm. The coefficient d is related to the tire contact pressure distribution. If the value of d is too small, the contact pressure on the tire shoulder is too large, resulting in abnormal wear of the tire shoulder; conversely, if the value of d is too large, the contact pressure on the tire crown is too large, resulting in abnormal wear of the tire crown.

[0057] 5. Rso is the outer arc of the profile connecting the sidewall curve and Rm. A smaller Rm value reduces the curvature and bending deformation of the tire shoulder, which helps improve rolling resistance.

[0058] 6. RSI shoulder inner radius. The tire shoulder is usually the part of the tire that generates the most heat, meaning it loses the most energy and contributes significantly to rolling resistance. Increasing the radius of the inner radius of the tire shoulder reduces the material thickness (volume) of the shoulder, which helps improve rolling resistance.

[0059] The present invention employs the above-mentioned technical solution. This method is based on the tire's rim width Wr. By coordinating the relationship between Wr and the tire's ground contact width Wt and height reduction h, it aims to reduce the curvature of the tire crown profile curve and improve tire rolling resistance. Attached Figure Description

[0060] Figure 1 Tire model and size diagram;

[0061] Figure 2 Tire mold dimension diagram;

[0062] Figure 3 A schematic diagram of the trapezoid formed by Wt and Wr;

[0063] Figure 4 Comparison of grounding pressure distribution under different c values;

[0064] Figure 5 Comparison of grounding pressure distribution under different d values;

[0065] Figure 6 Illustrations of different tire shoulder Rso curvatures;

[0066] Figure 7 Tire rolling resistance distribution diagram. Detailed Implementation

[0067] The present invention will be further described in detail below with reference to the accompanying drawings: This embodiment is implemented under the premise of the technical solution of the present invention, and detailed implementation methods are given, but the protection scope of the present invention is not limited to the following embodiments.

[0068] During contact with the ground, the curved tread of a tire comes into contact with the ground and undergoes bending deformation. The degree of bending is related to the initial tread curvature (for a given tire model, the tire pressure and load are constant). A smaller tread curvature results in a lower degree of bending after contact with the ground, corresponding to lower rolling resistance. Curvature is a characterization of the degree of curve bending, and its expression is:

[0069]

[0070] In the formula, K is the curvature of a point on the curve, r is the radius of curvature of the corresponding point, and Δα and Δs correspond to the radian and arc length of a point, respectively.

[0071] If we consider the entire tire crown area as a whole, the factors affecting the tire crown curvature are the tire's contact width Wt and the height drop h of the contact edge.

[0072] To improve tire rolling resistance, this invention employs the following technical solution: a method and product for designing a tire crown profile curve to improve rolling resistance, comprising the tire crown profile curve and tread, belt layers, sidewalls, tread rubber, and other components. Tire size limits are clearly defined in GB and ISO standards: section width SW, rim width Wr, outer diameter OD, rim diameter D, tire section height H (which is half the difference between the tire's outer diameter and the rim diameter, i.e., (OD-D) / 2), and section height-to-width ratio (the ratio of tire section height H to section width SW multiplied by 100%). Figure 1 As shown.

[0073] The tire contact patch width Wt, arc height h, tread radius Rc, tread radius Rm, and shoulder radius Rso and Rsi are design parameters. For example... Figure 2 .

[0074] The tire's contact patch width Wt and the rim width Wr form an isosceles trapezoid, such as... Figure 3 As shown, during tire loading, the vehicle load is transferred to the tire crown and the ground through the axle and rim. When the contact patch width Wt is close to the rim width Wr, load transfer is more efficient. That is, the tire contact patch width Wt and the rim width Wr form an approximate rectangle. In this case, the contact patch width Wt can significantly improve the tire's rolling resistance.

[0075] Referring to GB / T2978-2014, the rim width Wr and section height-to-width ratio are determined according to the specified tire model. For example: tire model 205 / 55R16, nominal section width SW = 205, tire outer diameter OD = 632, section height-to-width ratio is 55, the measured (used) rim is 6.5X16J, Wr = 6.5X25.4 = 165.1. Rim diameter D = 406.

[0076] 1. Design the tire contact width Wt based on the specified specification Wr. To ensure the rigid rim provides adequate support for the entire tire crown, the values ​​of Wr and Wt should be as consistent as possible, forming an approximate rectangle enclosed by Wr and Wt.

[0077] Wt=Wr·a, a=0.95~1.05.

[0078] While an excessively large ground contact width (a larger value) reduces the curvature of the tire crown under the same conditions, it also increases the material volume, which is detrimental to the tire's rolling resistance. On the other hand, an excessively small ground contact width (a smaller value) increases the curvature of the tire crown under the same conditions, thereby increasing the bending deformation of the tire crown and rolling resistance.

[0079] 2. Based on the value of the specified specification Wr, expressed as an expression Calculate the value of h. The value of b is selected according to the following range:

[0080] Cross-sectional height-to-width ratio ≦35 40～50 55～60 ≧65 b 3.08～3.22 2.81～3.01 2.57～2.79 2.35～2.55

[0081] The height *h* of the tire's contact patch edge directly affects the curvature of the tire crown, as shown in the above formula derived from the analysis of multiple sets of data. The tire's contact patch shape and pressure distribution are highly sensitive to changes in the *h* value, requiring careful selection. Different tire models may have the same rim width *Wr*. Therefore, when calculating the *h* value, in addition to considering the rim width *Wr*, the tire's section aspect ratio must also be taken into account.

[0082] The design should consider the h value in conjunction with Wr and coefficients a and b. An excessively large h value will increase the curvature of the tire crown, increase the bending deformation of the tire crown, and be detrimental to rolling resistance; while an excessively small h value will reduce the curvature of the tire crown, but will also increase the pressure distribution in the tire shoulder area, leading to abnormal wear in the tire shoulder.

[0083] 3. Based on the specified value of Wr, calculate Rc = Wr·b·c, where c = 1.2~2.0. The method for drawing the Rc arc: its center is located on the tire's centerline, and an arc with radius Rc is drawn with the tire's apex as the quadrant point. The coefficient c is related to the tire's ground contact pressure distribution. If the value of c is too large, the ground contact pressure on the tire shoulder is too high, leading to abnormal wear on the tire shoulder; conversely, if the value of c is too small, the ground contact pressure on the tire crown is too high, leading to abnormal wear on the tire crown. For example... Figure 4 .

[0084] 4. Based on the specified value of Wr, calculate Rm = Wr·b·d, where d = 0.35~0.65. The Rm arc is drawn as follows: tangent to Rc and passing through the lower end of the tire shoulder height h, with a radius of Rm. The coefficient d is related to the tire's contact pressure distribution. If d is too small, the contact pressure on the tire shoulder is too high, leading to abnormal wear on the tire shoulder; conversely, if d is too large, the contact pressure on the tire crown is too high, leading to abnormal wear on the tire crown. For example... Figure 5 .

[0085] 5. Rso = 12-20, outer shoulder rounded corner. Under the same conditions, a smaller radius of curvature at the shoulder rounded corner reduces the curvature of the shoulder area, which is beneficial for improving rolling resistance. For example... Figure 6 .

[0086] 6. Rsi = Rso · (1.1~1.3), the inner radius of the tire shoulder. The tire shoulder is usually the part of the tire that generates the most heat, meaning it loses the most energy and contributes significantly to rolling resistance. Increasing the radius of the inner radius of the tire shoulder reduces the material thickness (volume), which helps improve rolling resistance. Figure 7 .

[0087] Verification example:

[0088] Rolling resistance was determined according to ISO 28580 test method. Tire models and design parameters are shown in the table below:

[0089]

[0090]

[0091]

[0092] As shown in the table above, Examples 1 and 2 show improved tire rolling resistance compared to the reference example. Since the design parameters already consider the influence of tire contact pressure, the above design methods and products have no negative impact on tire wear properties.

[0093] The foregoing description of embodiments of the present invention, through which those skilled in the art are able to implement or use the present invention, will be readily apparent to those skilled in the art. Various modifications to these embodiments will be readily apparent to those skilled in the art. The general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novelty disclosed herein.

Claims

1. A tire for improving rolling resistance, the tire comprising a crown, a shoulder, a belt layer, a sidewall, and a bead, wherein the cross-sectional width SW of the crown profile curve, the rim width Wr, the outer diameter OD, the rim diameter D, the tire section height H (which is half the difference between the tire's outer diameter and the rim diameter), the section height-to-width ratio (which is the ratio of the tire section height H to the section width SW multiplied by 100%), the tire contact patch width Wt, the arc height h, the crown radius Rc, the crown radius Rm, the outer shoulder arc radius Rso, and the inner shoulder arc radius Rsi are design parameters; characterized in that, in: Wt=Wr·a, a=0.95~1.05; The choice for b is as follows: 1) Cross-sectional height-to-width ratio ≤ 35, b = 3.08~3.22, 2) Cross-sectional height-to-width ratio 40–50, b = 2.81–3.01, 3) The cross-sectional height-to-width ratio is 55–60, and b = 2.57–2.

79. 4) The aspect ratio of the cross-section is ≥65, and b = 2.35~2.55; Rc=Wr·b·c, c=1.2~2.0; Rm=Wr·b·d, d=0.35~0.65; Rso = 12~20; Rsi = Rso·(1.1~1.3).

2. The tire for improving rolling resistance according to claim 1, characterized in that, a=0.96~1.02; c=1.30~1.80; d=0.45~0.60; Rso=15~20.

3. A tire for improving rolling resistance according to claim 1, characterized in that, The choice for b is as follows: 1) Cross-sectional height-to-width ratio ≤ 35, b = 3.10~3.20, 2) The cross-sectional height-to-width ratio is 40–50, and b = 2.85–2.

95. 3) The cross-sectional height-to-width ratio is 55–60, and b = 2.60–2.

76. 4) The cross-sectional height-to-width ratio is ≥65, and b = 2.40~2.

50.

4. A tire design method for improving rolling resistance, the tire comprising a crown, a shoulder, a belt layer, a sidewall, and a bead, wherein the design parameters are: crown profile width SW, rim width Wr, outer diameter OD, rim diameter D, tire section height H (half the difference between the tire's outer diameter and the rim diameter), section height-to-width ratio (the ratio of tire section height H to section width SW multiplied by 100%), tire contact patch width Wt, arc height h, crown radius Rc, crown radius Rm, outer shoulder arc radius Rso, and inner shoulder arc radius Rsi; characterized in that... in: Wt=Wr·a, a=0.95~1.05; The choice for b is as follows: 1) Cross-sectional height-to-width ratio ≤ 35, b = 3.08~3.22, 2) Cross-sectional height-to-width ratio 40–50, b = 2.81–3.01, 3) The cross-sectional height-to-width ratio is 55–60, and b = 2.57–2.

79. 4) The aspect ratio of the cross-section is ≥65, and b = 2.35~2.55; Rc=Wr·b·c, c=1.2~2.0; Rm=Wr·b·d, d=0.35~0.65; Rso = 12~20; Rsi = Rso·(1.1~1.3).

5. The design method according to claim 4, characterized in that, a=0.96~1.02; c=1.30~1.80; d=0.45~0.60; Rso = 15~20.

6. The design method according to claim 4, characterized in that, The choice for b is as follows: 1) Cross-sectional height-to-width ratio ≤ 35, b = 3.10~3.20, 2) The cross-sectional height-to-width ratio is 40–50, and b = 2.85–2.

95. 3) The cross-sectional height-to-width ratio is 55–60, and b = 2.60–2.

70. 4) The cross-sectional height-to-width ratio is ≥65, and b = 2.40~2.

50.

7. The application of the design method according to any one of claims 4-6 in the design of tires with improved rolling resistance.

8. A computer device, comprising a memory, a processor, and a computer program stored in the memory, characterized in that, The processor executes the computer program to implement the method according to any one of claims 4-6.

9. A computer-readable storage medium having a computer program or instructions stored thereon, characterized in that, When the computer program or instructions are executed by a processor, they implement the method described in any one of claims 4-6.

10. A computer program product, comprising a computer program or instructions, characterized in that, When the computer program or instructions are executed by a processor, they implement the method described in any one of claims 4-6.

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