Railway vehicle tyre

Abstract

The present application relates to a rail vehicle tire, the cross-sectional inner profile above the cross-sectional horizontal axis is symmetrical relative to the tire center line, the half-width cross-sectional inner profile above the cross-sectional horizontal axis has a first profile, a second profile and a third profile in sequence; wherein the first profile passes through the cross-sectional inner profile center point, the first profile height perpendicular to the cross-sectional horizontal axis satisfies 15% <= L1 / L <= 29%; the first profile has three tangent arcs on one side of the tire center line, wherein the included angle between the line connecting the intersection point of the first arc (CR1) and the second arc (CR2) to the cross-sectional inner profile center point and the cross-sectional horizontal axis is 0.5 DEG <= theta1 <= 1.0 DEG; the included angle between the line connecting the intersection point of the second arc (CR2) and the third arc (CR3) to the cross-sectional inner profile center point and the cross-sectional horizontal axis is 2.0 DEG <= theta2 <= 2.5 DEG. The present application improves the rigidity of the crown, reduces the deformation of the tread, reduces the heat generation of the crown, reduces the shear strain and strain energy of the belt end point, and improves the safety performance and wear performance of the tire by adjusting the profile of the carcass.

Description

Technical Field

[0001] The present invention relates to the technical field of tires, and in particular to a railway vehicle tire. Background Art

[0002] To better adapt to express service scenarios such as suburban and tourist routes, rail vehicles are equipped with increasingly advanced high-speed capabilities. As a public transportation vehicle, they are also characterized by their heavy weight and high passenger volume per trip, which means that rail vehicle tire loads are higher than those of typical commercial vehicles. Furthermore, urban rail lines are limited by topographical and spatial constraints, and the rail vehicle and its corresponding track are designed as a system, requiring consideration of the overall height matching between the rail vehicle and track beam, as well as the coordination between the tire and track.

[0003] For the above rail vehicle application scenarios, end customers require not only good high-speed performance of tires, but also good load-bearing capacity and good wear performance when in contact with the track surface, so as to reduce tire wear and reduce the frequency of tire replacement.

[0004] Current rail vehicle tire design methods are immature, primarily based on commercial vehicle tire design experience. This makes it difficult to simultaneously address the performance requirements of high speed, high load capacity, and high wear. In fact, indoor drum testing has shown that under current process conditions, rail tires fail to meet performance requirements. Crown shoulder cracks can occur after a certain period of testing, leading to premature tire failure. Summary of the Invention

[0005] In view of the problems in the prior art, the present invention provides a railway vehicle tire.

[0006] The technical solution of the present invention provides a railway vehicle tire, wherein the inner profile of the cross section located above the horizontal axis of the cross section is symmetrical with respect to the center line of the tire, and the inner profile of the half cross section located above the horizontal axis of the cross section has a first profile, a second profile, and a third profile that are consecutive;

[0007] The first profile passes through the center point of the inner profile of the cross section, and the projection distance L1 of the first profile to the center line of the tire satisfies 15%≤L1 / L≤29%, where L is the height of the inner profile of the cross section perpendicular to the horizontal axis of the cross section;

[0008] The first contour is located on one side of the tire centerline and has three tangent arcs, starting from the center point of the inner contour, and are recorded as the first arc, the second arc and the third arc in sequence; the angle between the line connecting the intersection of the first arc and the second arc to the center point of the inner contour and the horizontal axis of the section is 0.5°≤θ1≤1.0°; the angle between the line connecting the intersection of the second arc and the third arc to the center point of the inner contour and the horizontal axis of the section is 2.0°≤θ2≤2.5°.

[0009] Preferably, the distance TS from the third arc to the end point of the shoulder and the tread thickness TT at the center point of the inner contour satisfy 1.3≤TS / TT<1.4.

[0010] Preferably, the second contour is a fourth arc, the third contour is a fifth arc, and the arc lengths satisfy 1.2≤CR4 / CR3≤1.6 and 1.0≤CR5 / CR4≤1.4.

[0011] Preferably, there are four belt layers, which are designated as the first belt layer, the second belt layer, the third belt layer and the fourth belt layer in the order from the inner contour to the outer contour of the tread; and the laying directions of adjacent belt layers cross each other.

[0012] Preferably, the cord laying angle of the first belt layer is 21°≤D1B≤27°, the cord laying angle of the second belt layer is -24°≤D2B≤-21°, the cord laying angle of the third belt layer is 18°≤D3B≤24°, the cord laying angle of the fourth belt layer is -24°≤D4B≤-18°, and the absolute value of the cord angle of the third belt layer is smaller than that of the first, second and fourth cord layers, where the negative sign only indicates that the laying directions are opposite. The above-mentioned belt layer angle: the angle formed by the belt layer and the circumferential direction of the tread is recorded as the belt layer angle.

[0013] Preferably, the width W2B of the second belt layer satisfies W2B / TDW=0.84~0.94, where TDW is the width between the two shoulders.

[0014] Tread width;

[0015] The widths of the first and third belt layers satisfy W3B=W2B-D, W1B=W2B-D, where D is a constant value of 10-15mm;

[0016] The width of the fourth belt layer satisfies W4B / TDW=0.60~0.65.

[0017] Preferably, the four belt layers have closely fitting segments starting from the tire centerline, and the closely fitting segments are separated at separation points, which are located more than 2 / 3 on one side of the centerline of the second belt layer profile and do not exceed the end of the fourth belt layer.

[0018] Preferably, the minimum breaking force of the first belt layer and the fourth belt layer should be between 1200-2000N, and the minimum breaking force of the second belt layer and the third belt layer should be between 2200-3000N.

[0019] Preferably, the radii of the first arc, the second arc and the third arc are defined as a first arc radius TR1, a second arc radius TR2 and a third arc radius TR3 in sequence, the first arc radius TR1 ranges from 700 to 1000 mm, and the three satisfy TR3 < TR2 < TR1; TR2 / TR3 = 2-3.

[0020] Preferably, the height difference between the highest point of the tread contour and the lowest point at the boundary between the tread and the shoulder is defined as a crown height HH, and the crown height HH is 3.1% of the cross-sectional height SH of the tire.

[0021] Preferably, the tread material of the rail vehicle tire adopts a double-layer design, including a first tread located at an outer layer of the tread and a second tread located at an inner layer of the tread. The first tread adopts a high-wear formula design, and the second tread adopts a low-heat generation formula design, and the heat generation coefficient ranges from 0.018 to 0.026.

[0022] Preferably, the thickened position of the second tread covers the first belt layer endpoint, the second belt layer endpoint and the third belt layer endpoint, the thickened position of the second tread has a thickness dimension h ranging from 3.5 to 5 mm, and the thickened position of the second tread has a horizontal distance W2 from the cross-sectional inner contour center point ranging from a fourth belt layer width to a second belt layer width plus E; E is 7 mm, and the thickness of other positions of the second tread ranges from 2 to 3.5 mm.

[0023] Preferably, the groove depth GD of the tread ranges from 7.5 to 8.5 mm.

[0024] The present application improves the rigidity of the crown, reduces the deformation of the tread and the heat generation of the crown by adjusting the cross section of the carcass. Meanwhile, the shear strain and strain energy of the belt layer endpoint are reduced by adjusting the tire outer contour, the structure and angle of the belt layer and the width, which improves the safety performance and wear performance of the tire. The heat generation of the tire is further reduced by reducing the crown groove depth and adopting a low-heat generation second tread design, which improves the heat dissipation of the tire and ensures the safety performance at high speed. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 Fig. 1 is a schematic diagram of the cross section of the rail vehicle tire of the present application;

[0026] Figure 2 Fig. 2 is a schematic diagram of the details of the cross section of the rail vehicle tire of the present application;

[0027] Figure 3 Fig. 3 is a schematic diagram of the partial enlarged view of the rail vehicle tire of the present application in the middle; Figure 2

[0028] Figure 4 Fig. 4 is a schematic diagram of the belt layer laying of the rail vehicle tire of the present application; and ​

[0029] Figure 5 A schematic diagram of the layered arrangement of the belt layer of a railway vehicle tire according to the present invention;

[0030] Figure 6 Schematic diagram of belt layer laying of Comparative Examples 1 and 2 of the present invention;

[0031] Figure 7 Schematic diagram of the tread layering arrangement of a railway vehicle tire according to the present invention. DETAILED DESCRIPTION

[0032] 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 positional relationship and connection relationship between the various components. Components with the same name or the same number represent similar or identical structures and are only for illustrative purposes.

[0033] The rail vehicle tire of the present invention has an optimized tire profile, and the radial section of the rail vehicle tire intersects with the inner surface of the tire to form a tire cross section. Figure 1 、 Figure 2 as well as Figure 3The tire cross section (not including the tread pattern by default) is symmetrical relative to the tire center line. The cross section horizontal axis is defined as the connecting line of the widest part of the tire in the axial direction, and the cross section inner contour has a first contour, a second contour and a third contour successively on the side of the horizontal axis of the cross section. The cross section inner contour height L is defined as the distance from the inner contour center point to the horizontal axis. The first contour passes through the inner contour center point, and the height L1 of the first contour satisfies 15%≤L1 / L≤29%; the height L2 of the second contour satisfies 39%≤L2 / L≤51%, and the height L3 of the third contour satisfies 30%≤L3 / L≤36%. For the carcass arcs CR4 and CR5, 1.2≤CR4 / CR3≤1.6, 1.0≤CR5 / CR4≤1.4. On the side of the tire center line, the first contour has three tangent arcs, and there are three tangent arcs successively from the inner contour center point to the second contour, which are respectively referred to as the first arc CR1, the second arc CR2 and the third arc CR3. The included angle between the line connecting the intersection point of the first arc CR1 and the second arc CR2 to the inner contour center point and the cross section horizontal axis is 0.5°≤θ1≤1.0°. The included angle between the line connecting the intersection point of the second arc CR2 and the third arc CR3 to the inner contour center point and the cross section horizontal axis is 2.0°≤θ2≤2.5°. The third arc CR3 extends from the inner side of the tread to the inner side of the sidewall, so it passes through the inner side of the shoulder, and the distance TS from the third arc CR3 to the shoulder end point and the tread thickness TT at the inner contour center point satisfy 1.3≤TS / TT<1.4. The three tangent arcs of the crown are tangent successively, and their radii are defined as the first arc radius TR1, the second arc radius TR2 and the third arc radius TR3 successively. The value range of TR1 is 700~1000mm, TR3<TR2<TR1; TR2 / TR3=2~3. The profile transition from the tread to the shoulder is completed by changing the radii.

[0034] In general, the above tread thickness TT, based on the 2B width, at 0~2 / 3 of the 2B width, the tread thickness at each position hardly changes, so it is beneficial to improve the load bearing property of the tread under heavy load, make the tread bear pressure more evenly in the axial direction, and avoid local overheating and failure of the tread. On this basis, by controlling the distance TS from the third arc CR3 to the shoulder end point at the shoulder, on the one hand, the shape of the ground contact is ensured, and on the other hand, the shear strain of the belt end point is reduced as much as possible, so as to match the wear and safety performance of the tire.

[0035] As Figure 4As shown, the rail vehicle tire adopts a four-layer belt structure design. In order from the outer contour of the tread to the inner contour, the four belt layers are designated as the first belt layer 1B, the third belt layer 2B, the third belt layer 3B, and the fourth belt layer 4B. The laying directions of the cords in the belt layers intersect with each other. The cord laying angle of the first belt layer 1B is 21° ≤ D1B ≤ 27°, the cord laying angle of the second belt layer 2B is -24° ≤ D2B ≤ -21°, the cord laying angle of the third belt layer 3B is 18° ≤ D3B ≤ 24°, and the cord laying angle of the fourth belt layer 4B is -24° ≤ D4B ≤ -18°. The absolute value of the cord angle of the third belt layer 3B is smaller than that of the first belt layer 1B, the second belt layer 2B, and the fourth belt layer 4B. The negative sign simply indicates that the laying directions are opposite.

[0036] like Figure 5 As shown, TDW is the tread width between the two shoulders. The width of the second belt layer, W2B, satisfies W2B / TDW = 0.84-0.94. Based on this, the widths of the first and third belt layers, 1B and 3B, satisfy W3B = W2B-D and W1B = W2B-D, respectively, where D is a constant value, typically 10-15 mm. The width of the fourth belt layer, 4B, satisfies W4B / TDW = 0.60-0.65. Clearly, the second belt layer has the maximum width. Based on the second belt layer, the four belt layers are closely fitting segments, separated at their ends at the shoulders. The separation point, B, is typically defined as a point at least two-thirds of the way along the second belt layer on one side of the centerline of the tire profile, but not exceeding the end of the fourth belt layer. Therefore, the belt layers extending from the centerline of the tire profile to the separation point, B, are stacked parallel to each other and are generally parallel to the inner profile. The material density of each belt layer is preferably 40 strands / dm, with the minimum breaking force of the first and fourth belt layers being 1850 N. The material density of each belt layer is preferably 40-45 strands / dm, with the minimum breaking force of the first and fourth belt layers being 1850 N. The minimum breaking force of the first and fourth belt layers should be between 1200-2000 N, and the minimum breaking force of the second and third belt layers 2B and 3B should be between 2200-3000 N.

[0037] The portion beyond separation point B, located primarily on the inner side of the tire shoulder, has limited load-bearing requirements but significant deformation. Tightly fitting multiple belt layers can lead to shoulder debonding after prolonged deformation. Therefore, the areas between the belt layers beyond separation point B are often filled with a specific rubber compound to separate them. Specifically, a rubber profile is placed between the second belt layer 2B and the third belt layer 3B. Preferably, each belt layer edge is provided with a rubber band, with the width W3 of the band on the second belt layer being greater than the width W4 of the rubber profile to ensure that the rubber profile does not come into direct contact with the cords of the second belt layer.

[0038] like Figure 6As shown, the tread material of the rail vehicle tire adopts a double-layer design, i.e., a first tread located at the outer layer of the tread and a second tread located at the inner layer of the tread, and the second tread is between the first tread and the first belt 1B. The first tread adopts a high-wear formula design, and the second tread adopts a low-heat formula design, and the heat generation coefficient ranges from 0.018 to 0.026. The above heat generation coefficient = tan δ / E' 1 / 2 , tan δ = loss modulus E” of the tread rubber / storage modulus E’.

[0039] The thickness of the second tread is non-uniform, and the thicker position covers the end points of the first belt, the end points of the second belt and the end points of the third belt. Figure 6 For a specific example, the thickness of the second tread ranges from h = 2 to 3.5 mm, 0 ≤ W1 ≤ 4B width; h = 3.5 to 5 mm, 4B width < W2 ≤ 2B width + E; and E is 7 mm. That is, the end points of 1B and 3B which are prone to damage are ensured to be below the thickest position of the second tread. The height of the tread is slightly reduced from the profile center line to the shoulder under the control of the radius of the tangent arc at the tread and the shape control of the first tread and the second tread, and the amount of reduction is determined by the height of the highest point of the tread profile and the lowest point at the boundary between the tread and the shoulder, which is defined as the arc crown height HH, and the arc crown height HH is preferably 3.1% of the tire cross-sectional height SH, so that under the standard state pressure, the crown deformation makes the stress of the tread more uniform in the axial direction, which can reduce the internal stress variation caused by uneven stress, and is beneficial to prolong the service life.

[0040] In order to further reduce the heat generation of the tread, preferably, the tread groove depth GD is 7.5 to 8.5 mm.

[0041] A number of embodiments and comparative examples are selected for analysis and verification. For the end points of the belt, the end points of 1B and 3B which are prone to damage are extracted, and the shear strain and strain energy of the end points are calculated. The smaller the shear strain and strain energy, the less prone the end points are to damage, and the higher the safety performance of the tire is. At the same time, the ground contact rectangular rate, the average ground contact pressure and the standard deviation of the ground contact pressure under different working conditions are calculated by finite element simulation; the closer the ground contact rectangular rate to 100%, the more uniform the ground contact shape is, and the smaller the average ground contact pressure and the standard deviation of the ground contact pressure, the more uniform the ground contact pressure is; the more uniform the ground contact shape and the ground contact pressure are, the better the wear performance of the tire is.

[0042] For different carcass profiles, the numerical values of the common failure modes are compared and analyzed; the results are shown in Table 1.

[0043]

[0044] Table 1

[0045] Comparative Example 1 is a current product solution; Examples 1 to 6 are carcass profile optimization solutions based on Comparative Example 1.

[0046] In the above table, the definition of each performance index is as follows: the 1B / 3B shear strain and strain energy, average ground pressure, and standard deviation of ground pressure of Comparative Example 1 (the current product solution) are used as the benchmark 100, and the actual calculated values ​​of other solutions are compared with the calculated values ​​of Comparative Example 1.

[0047] As can be seen from the table above, in terms of 1B / 3B shear strain and strain energy, Examples 1 to 6 are all superior to Comparative Example 1; in terms of grounding rectangularity, average grounding pressure index, and grounding pressure standard deviation index, Examples 1 to 6 are all superior to Comparative Example 1.

[0048] For different belt layer structures and angle schemes, the relevant results are extracted and shown in Table 2 below.

[0049]

[0050] Table 2

[0051] Comparative Example 2 follows the scheme of Example 1 in Table 1, with a 3+0°B belt structure. Examples 7-11, based on Comparative Example 2, modify the belt structure and belt angles to adopt a 4B belt structure. As shown in the table above, Examples 7-11 outperform Comparative Example 1 in terms of 3B shear strain and strain energy. Furthermore, Examples 7-11 are comparable to Comparative Example 2 in terms of 3B shear strain and strain energy, ground contact squareness, average ground contact pressure index, and ground contact pressure standard deviation index.

[0052] In order to investigate the schemes with different groove depths and whether or not to include a second tread, the relevant results are extracted and shown in Table 3 below.

[0053]

[0054] Table 3

[0055] Comparative Example 1 is the current product solution in Table 1; Comparative Example 3 is the solution of Example 10 in Table 2; Examples 12-13 are based on Comparative Example 3, but with the groove depth and whether or not a second tread is included changed, and simulation analysis and indoor drum test verification were performed.

[0056] The durability test index in the table above is defined as follows: The indoor durability test data of Comparative Example 1 (the current product solution) is used as a baseline of 100, and the actual indoor durability test data of the other embodiments are compared with the indoor durability test data of Comparative Example 1. A higher durability test index indicates better durability and a safer tire.

[0057] The table above shows that as the groove depth decreases, the endpoint shear strain and strain energy of Examples 12 and 13 are slightly lower than those of Example 12 and Comparative Example 3 (1B and 3B), which is beneficial for safety performance. Based on previous experience, conventional simulation analysis primarily examines the impact of tire structure and profile on belt endpoints and cannot examine the impact of the second tread on durability indicators. Actual tire production and indoor drum testing indicate that the durability test index of Example 13 is higher than that of Example 12 and both are higher than Comparative Example 1. Therefore, the inclusion of a second tread has a positive impact on safety performance.

[0058] The above content only describes the preferred embodiments 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 scope of protection determined by the claims of the present invention.

Claims

1. A railway vehicle tire, characterized in that: The inner profile of the cross section above the horizontal axis of the cross section is symmetrical with respect to the center line of the tire, and the inner profile of the half cross section above the horizontal axis of the cross section has a first profile, a second profile, and a third profile that are consecutive; Among them, the first contour passes through the center point of the inner contour of the cross section, and its first contour height perpendicular to the horizontal axis of the cross section meets 15%≤L1 / L≤29%, the height L2 of the second contour meets 39%≤L2 / L≤51%, and the height L3 of the third contour meets 30%≤L3 / L≤36%, where L is the inner contour height from the center point of the inner contour of the cross section to the horizontal axis of the cross section; The first profile is located on one side of the tire centerline and has three tangent arcs, starting from the center point of the inner profile and marked as the first arc (CR1), the second arc (CR2), and the third arc (CR3). The angle between the line connecting the intersection of the first arc (CR1) and the second arc (CR2) to the center point of the inner profile and the horizontal axis of the cross section is 0.5°≤θ1≤1.0°; the angle between the line connecting the intersection of the second arc (CR2) and the third arc (CR3) to the center point of the inner profile and the horizontal axis of the cross section is 2.0°≤θ2≤2.5°. The distance TS from the shoulder endpoint to the third arc (CR3) and the tread thickness TT at the center point of the inner contour meet the requirement of 1.3≤TS / TT<1.4; The second contour is a fourth arc CR4, the third contour is a fifth arc CR5, and the arc lengths satisfy 1.2≤CR4 / CR3≤1.6, and 1.0≤CR5 / CR4≤1.4; The railway vehicle tire further comprises four belt layers, which are designated as a first belt layer (1B), a second belt layer (2B), a third belt layer (3B), and a fourth belt layer (4B) in the order from the inner contour of the tread to the outer contour of the tread; the laying directions of the cords in the belt layers are mutually crossed in pairs; The cord laying angle of the first belt layer (1B) is 21°≤D1B≤27°, the cord laying angle of the second belt layer (2B) is -24°≤D2B≤-21°, the cord laying angle of the third belt layer (3B) is 18°≤D3B≤24°, and the cord laying angle of the fourth belt layer (4B) is -24°≤D4B≤-18°, and the absolute value of the cord angle of the third belt layer (3B) is smaller than that of the first belt layer (1B), the second belt layer (2B) and the fourth belt layer (4B), wherein the negative sign only indicates that the laying directions are opposite, and the cord laying angle refers to the angle formed by the belt layer and the circumferential direction of the tread.

2. The rail vehicle tire according to claim 1, wherein: The width of the second belt layer W2B satisfies W2B / TDW=0.84~0.94, where TDW is the tread width between the two shoulders; The widths of the first belt layer (1B) and the third belt layer (3B) satisfy W3B=W2B-D, W1B=W2B-D, where D is a constant value of 10-15 mm; The width of the fourth belt layer (4B) satisfies W4B / TDW=0.60~0.

65.

3. The railway vehicle tire according to claim 2, wherein: The four belt layers have closely fitting segments starting from the tire centerline, and the closely fitting segments are separated at separation points, which are located more than 2 / 3 on one side of the centerline of the second belt layer profile and do not exceed the end of the fourth belt layer.

4. The railway vehicle tire according to claim 3, wherein: The minimum breaking force of the first belt layer and the fourth belt layer is between 1200-2000N, and the minimum breaking force of the second belt layer (2B) and the third belt layer (3B) is between 2200-3000N.

5. The railway vehicle tire according to claim 1, wherein: The radii of the first arc, the second arc, and the third arc are defined as the first arc radius TR1, the second arc radius TR2, and the third arc radius TR3, respectively. The value range of the first arc radius TR1 is 700~1000mm, and the three satisfy TR3<TR2<TR1; TR2 / TR3=2~3.

6. The railway vehicle tire according to claim 5, wherein: The height difference between the highest point of the tread profile and the lowest point of the boundary between the tread and the shoulder is defined as the arc crown height HH, and the arc crown height HH is 3.1% of the tire section height SH.

7. The railway vehicle tire according to claim 1, wherein: The tread material of rail vehicle tires adopts a two-layer design, consisting of a first tread located on the outer layer of the tread and a second tread located on the inner layer of the tread. The first tread adopts a high-wear formula design, while the second tread adopts a low-heat generation formula design, with a heat generation coefficient range of: 0.018~0.

026.

8. The railway vehicle tire according to claim 7, wherein: The thickened position of the second tread covers the end points of the first belt layer, the second belt layer and the third belt layer. The thickness dimension h of the thickened position of the second tread ranges from h=3.5~5mm. The horizontal distance W2 between the thickened position of the second tread and the center point of the inner contour of the cross section ranges from the width of the fourth belt layer (4B) < W2 ≤ the width of the second belt layer (2B) + E; where E is 7mm. The thickness range of other positions of the second tread is 2~3.5mm.

9. The railway vehicle tire according to claim 1, wherein: The tread groove depth GD is 7.5~8.5mm.

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