Railway vehicle tire

Abstract

The invention relates to a railway vehicle tire which is characterized in that a section inner contour positioned above a section horizontal axis is symmetrical relative to a tire center line, and a half section inner contour positioned above the section horizontal axis is provided with a first contour, a second contour and a third contour which are connected; wherein the first contour passes through the central point of the inner contour of the section, and the height of the first contour vertical to the horizontal axis of the section meets 15% < = L1 / L < = 29%; the first profile is provided with three sections of tangent arcs on one side of the center line of the tire, and an included angle theta between a connecting line from the intersection point of a first arc (CR1) and a second arc (CR2) to the center point of the inner profile and the horizontal axis of the section is more than or equal to 0.5 degree and less than or equal to 1.0 degree; and an included angle theta 2 between a connecting line from the intersection point of the second arc (CR2) and the third arc (CR3) to the central point of the inner contour and the horizontal axis of the section is greater than or equal to 2.0 degrees and less than or equal to 2.5 degrees. By adjusting the tire body contour, the rigidity of the crown part is improved, the tread deformation is reduced, the heat generation of the crown part is reduced, the endpoint shear strain and strain energy of the belted layer are reduced, and the safety performance and abrasion performance of the tire are improved.

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] In order to better adapt to the operation scenarios of express trains in suburban areas, tourist routes, etc., rail vehicles have more and more advanced high-speed performance. At the same time, as a public transportation tool, it has the characteristics of heavy weight and large passenger flow per single trip, which means that the tire load of rail vehicles is higher than that of general commercial vehicles. At the same time, urban rail lines are limited in design due to terrain and space restrictions. The rail vehicles and the corresponding tracks are designed as a system, and it is necessary to consider the overall height matching of the rail vehicles and the track beams and the coordination between the tires and the tracks.

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

[0004] The current design of rail vehicle tires is not mature yet, and is mainly based on the design experience of commercial vehicle tires. It is difficult to take into account the performance requirements of high speed, high load and high wear at the same time. In fact, the indoor drum test shows that the performance of rail tires under current process conditions does not meet the requirements, and the crown shoulder crack phenomenon will occur after a certain period of time in the experiment, causing the tire to fail prematurely. 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 rail 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-width cross section located above the horizontal axis of the cross section has a continuous first profile, a second profile and a third profile; Wherein, the first contour passes through the center point of the inner contour of the cross section, and the projection distance L1 of the first contour to the center line of the tire satisfies 15%≤L1 / L≤29%, where L is the height of the inner contour of the cross section perpendicular to the horizontal axis of the cross section; 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°.

[0007] 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.

[0008] 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.

[0009] Preferably, there are four belt layers, which are recorded 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 of the tread to the outer contour of the tread; the laying directions of adjacent belt layers are mutually crossed.

[0010] 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, wherein 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.

[0011] 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. Tread width; The width of the first belt layer and the third belt layer satisfies W3B=W2B-D, W1B=W2B-D, where D is a constant value of 10~15mm; The width of the fourth belt layer satisfies W4B / TDW=0.60~0.65.

[0012] 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.

[0013] 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.

[0014] Preferably, 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.

[0015] Preferably, the height difference between the highest point of the tread profile and the lowest point at the boundary between the tread and the shoulder is defined as the crown height HH, and the crown height HH is 3.1% of the tire section height SH; Preferably, the tread material of the railway vehicle tire adopts a double-layer design, which is 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, and the second tread adopts a low-heat generation formula design, with a heat generation coefficient range of 0.018-0.026.

[0016] Preferably, the thickened position of the second tread covers the end point of the first belt layer, the end point of the second belt layer and the end point of the third belt layer, the thickness dimension h of the thickened position of the second tread ranges from h=3.5~5mm, and the horizontal distance W2 from the thickened position of the second tread to the center point of the inner contour of the cross-section is in the range of: the fourth belt layer width <W2≤the second belt layer width+E; where E is 7mm, and the thickness range of other positions of the second tread is 2~3.5mm.

[0017] Preferably, the tread groove depth GD is 7.5-8.5 mm.

[0018] The present invention improves the rigidity of the crown, reduces tread deformation, and reduces the heat generation of the crown by adjusting the tire body contour; at the same time, by adjusting the tire outer contour, belt layer structure, angle, width and other structures, the shear strain and strain energy of the belt layer end points are reduced, which not only improves the safety performance of the tire, but also improves the wear performance of the tire. By reducing the crown groove depth and adopting a low-heat-generating second tread design, the heat generation of the tire is further reduced, the heat dissipation of the tire is improved, and the safety performance at high speed is ensured. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a schematic cross-sectional view of a rail vehicle tire of the present invention; Figure 2 A schematic diagram of the cross-section details of a railway vehicle tire of the present invention; Figure 3 The rail vehicle tire of the present invention is Figure 2 A magnified schematic diagram of a part in the figure; Figure 4 It is a schematic diagram of laying the belt layer of the railway vehicle tire of the present invention; Figure 5 A schematic diagram of the layered arrangement of the belt layer of a railway vehicle tire of the present invention; Figure 6 Schematic diagram of belt layer laying of Comparative Examples 1 and 2 of the present invention; Figure 7 It is a schematic diagram of the tread layering arrangement of the railway vehicle tire of the present invention. DETAILED DESCRIPTION

[0020] 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.

[0021] 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 3 As shown, the tire section (excluding the tread pattern by default) is symmetrical with respect to the tire centerline. The horizontal axis of the section is defined as the connecting line of the widest part of the tire axial direction. The inner contour of the section is located on the tread side of the horizontal axis of the section and has a first contour, a second contour and a third contour that are connected. The height L of the inner contour of the section is defined as the distance from the center point of the inner contour to the horizontal axis. The first contour passes through the center point of the inner contour of the section, 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 and 1.0≤CR5 / CR4≤1.4 are satisfied. There are three tangent arcs on the first contour located on the side of the tire centerline. There are three tangent arcs from the center point of the inner contour to the second contour, which are recorded as the first arc CR1, the second arc CR2 and the third arc CR3. The angle between the line from the intersection of the first arc CR1 and the second arc CR2 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 from the intersection of the second arc CR2 and the third arc CR3 to the center point of the inner contour and the horizontal axis of the section 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 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. The three tangent arcs of the crown are tangent to each other in sequence, and their radii are defined as the first arc radius TR1, the second arc radius TR2 and the third arc radius TR3 in sequence. The value range of TR1 is 700~1000mm, TR3<TR2<TR1; TR2 / TR3=2~3. The transition of the profile from the tread to the shoulder is completed by changing the radius.

[0022] In general, the tread thickness TT is based on the 2B width. At 0~2 / 3 of the 2B width, the tread thickness is almost unchanged, which is conducive to improving the tread's load-bearing capacity under heavy loads, making the tread more evenly stressed in the axial direction, and helping to avoid local overheating and failure of the tread. On this basis, at the shoulder, by controlling the distance TS from the third arc CR3 to the shoulder end point, the ground contact shape is ensured on the one hand, and the shear strain at the belt end point is minimized on the other hand, thereby matching the tire's wear and safety performance.

[0023] like Figure 4 As shown, the rail vehicle tire adopts a four-layer belt structure design, and the four belt layers are recorded as the first belt layer 1B, the third belt layer 2B, the third belt layer 3B and the fourth belt layer 4B in the order from the outer contour of the tread to the inner contour of the tread. The laying directions of the cords in the belt layers are mutually crossed. Among them, 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. The negative sign only indicates that the laying directions are opposite.

[0024] like Figure 5 As shown, the tread width between the two shoulders is TDW, and the width of the second belt layer W2B satisfies W2B / TDW=0.84~0.94. On this basis, 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, which can be 10~15mm. The width of the fourth belt layer 4B satisfies W4B / TDW=0.60~0.65. Obviously, the second belt layer has the maximum width. Taking the second belt layer as the reference, the four belt layers have tightly fitting segments and are separated at their ends located at the shoulders. Usually, the separation point B is defined at more than 2 / 3 of the second belt layer on one side of the center line of the contour and does not exceed the end of the fourth belt layer. Therefore, the belt layers extending from the center point of the contour to the separation point B are stacked in parallel and are generally parallel to the inner contour. The material density of each belt layer is preferably 40 pieces / dm, and the minimum breaking force of the first belt layer and the fourth belt layer is 1850 N. The material density of each belt layer is preferably 40-45 pieces / dm, and the minimum breaking force of the first belt layer and the fourth belt layer is 1850 N. The minimum breaking force of the first belt layer and the fourth belt layer should be between 1200-2000 N, and the minimum breaking force of the second belt layer 2B and the third belt layer 3B should be between 2200-3000 N.

[0025] The part beyond the separation point B is basically located on the inner side of the shoulder. Its load-bearing demand is limited but the deformation is large. The close fit of multiple belt layers will cause the shoulder to debond after long-term deformation. Therefore, the belt layers protruding from the separation point B are often filled with a certain amount of rubber to separate the belt layers. Specifically, the rubber profile is filled between the second belt layer 2B and the third belt layer 3B. Preferably, the edges of the belt layers are provided with edge wrapping films, wherein the width W3 of the edge wrapping film of the second belt layer is greater than the width W4 of the rubber profile to ensure that the rubber profile does not directly contact the cords of the second belt layer.

[0026] like Figure 6 As shown, the tread material of the rail vehicle tire adopts a double-layer design, which is a first tread located on the outer layer of the tread and a second tread located on the inner layer of the tread. The second tread is between the first tread and the first belt layer 1B. The first tread adopts a high wear formula design, and the second tread adopts a low heat generation formula design. The heat generation coefficient ranges from 0.018 to 0.026. The above heat generation coefficient = tanδ / E' 1 / 2 , tanδ = tread rubber loss modulus E” / storage modulus E'.

[0027] The thickness of the second tread is non-uniform, and thicker positions thereof cover the first belt layer end point, the second belt layer end point and the third belt layer end point. Figure 6 As a specific example, the second tread thickness dimension h ranges from: h = 2 to 3.5 mm, 0 ≤ W1 ≤ 4B width; h = 3.5 to 5 mm, 4B width < W2 ≤ 2B width + E; where E is 7 mm. That is, ensure that the endpoints of 1B and 3B, which are prone to damage, are below the thickest position of the second tread. 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, the tread height is slightly reduced from the center line of the contour to the shoulder. The reduction is determined by the height of the highest point of the tread contour and the lowest point at the boundary between the tread and the shoulder, which is defined as the arc crown height HH. The arc crown height HH is preferably 3.1% of the tire section height SH, so that when under pressure under standard conditions, the crown deforms so that the force on the tread is more uniform in the axial direction, which can reduce the internal stress changes caused by uneven force and help extend its service life.

[0028] In order to further reduce the heat generated by the tread, preferably, the tread groove depth GD is: 7.5~8.5mm.

[0029] This application has selected several embodiments and comparative examples for analysis and verification. For the endpoints of the belt layer, the endpoints that are prone to damage, the shear strain and strain energy of the endpoints 1B and 3B, are extracted. The smaller the shear strain and strain energy, the less likely the endpoints are to be damaged, and the higher the safety performance of the tire; at the same time, the ground contact rectangularity, average ground contact pressure, and ground contact pressure standard deviation under different working conditions are calculated through finite element simulation; the closer the ground contact rectangularity is to 100%, the more uniform the ground contact shape is, the smaller the average ground contact pressure and ground contact pressure standard deviation are, the more uniform the ground contact pressure is; when the ground contact shape and ground contact pressure are more uniform, the wear performance of the tire is better.

[0030] For different carcass profiles, the extracted values ​​of common failure modes are compared and analyzed; the results are shown in Table 1 below.

[0031]

[0032] Table 1 Comparative Example 1 is a current product solution; Examples 1 to 6 are carcass profile optimization solutions based on Comparative Example 1.

[0033] In the above table, the definition of each performance index is: taking the 1B / 3B shear strain and strain energy, average ground pressure, and standard deviation of ground pressure of Comparative Example 1, i.e. the current product solution, as the benchmark 100, the actual calculated values ​​of other solutions are compared with the calculated values ​​of Comparative Example 1.

[0034] It can be seen from the above table that the shear strain and strain energy of 1B / 3B of Examples 1 to 6 are better than those of Comparative Example 1; the grounding rectangularity rate, average grounding pressure index, and grounding pressure standard deviation index of Examples 1 to 6 are better than those of Comparative Example 1.

[0035] For different belt layer structures and angle schemes, the relevant results are extracted and shown in Table 2 below.

[0036]

[0037] Table 2 Comparative Example 2 is the scheme of Example 1 in Table 1, and the structure of the belt layer is 3+0°B structure; Examples 7 to 11 are based on the scheme of Comparative Example 2, and the belt layer structure and belt layer angle scheme are changed, and the belt layer structure is adjusted to 4B structure. It can be seen from the above table that the shear strain and strain energy of 3B, Examples 7 to 11 are better than Comparative Example 1; the shear strain and strain energy of 3B, ground contact rectangularity, average ground contact pressure index, and ground contact pressure standard deviation index, Examples 7 to 11 are equivalent to Comparative Example 2.

[0038] In order to investigate the schemes of different groove depths and whether or not to include a second tread, the relevant results are extracted and shown in Table 3 below.

[0039]

[0040] Table 3 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 to 13 are based on Comparative Example 3, with the groove depth and whether the second tread is included changed, and simulation analysis and indoor drum test verification are carried out.

[0041] Definition of the durability test index in the above table: The indoor durability test data of Comparative Example 1, i.e., the current product solution, is taken as the benchmark 100, and the actual indoor durability test data of other embodiments are compared with the indoor durability test data of Comparative Example 1. The larger the durability test index, the better the durability and the safer the tire.

[0042] It can be seen from the table above that as the groove depth decreases, the end point shear strain and strain energy of Examples 12 and 13 are slightly lower than those of 1B and 3B of Example 12 and Comparative Example 3, which is beneficial to safety performance; based on previous experience, conventional simulation analysis mainly examines the influence of the tire structure and profile on the end point of the belt layer, and cannot examine the influence of the second tread on the durability index. Therefore, through actual tire making and indoor drum verification, it can be seen 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 the second tread is beneficial to safety performance.

[0043] 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 railway vehicle tire, characterized in that: 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 connected in succession; 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 satisfies 15%≤L1 / L≤29%, where L is the height of the inner contour of the cross section from the center point of the inner contour of the cross section to the horizontal axis of the cross section; 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 (CR1), the second arc (CR2) and the third arc (CR3) in sequence; wherein 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 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 (CR2) and the third arc (CR3) to the center point of the inner contour and the horizontal axis of the section is 2.0°≤θ2≤2.5°.

2. The rail vehicle tire according to claim 1, characterized in that: The distance TS from the end point of the shoulder to the third arc (CR3) and the tread thickness TT at the center point of the inner contour satisfy 1.3≤TS / TT<1.

4.

3. The rail vehicle tire according to claim 1, characterized in that: 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.

4. The rail vehicle tire according to any one of claims 1 to 3, characterized in that: The invention has four belt layers, which are designated as the first belt layer (1B), the second belt layer (2B), the third belt layer (3B) and the 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.

5. The rail vehicle tire according to claim 4, characterized in that: 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°, 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.

6. The rail vehicle tire according to claim 5, characterized in that: The width W2B of the second belt layer 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.

7. The rail vehicle tire according to claim 6, characterized in that 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.

8. The rail vehicle tire according to claim 7, characterized in that 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.

9. The rail vehicle tire according to claim 1, characterized in that: 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.

10. The rail vehicle tire according to claim 9, characterized in that The height difference between the highest point of the tread profile and the lowest point at 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.

11. The rail vehicle tire according to claim 4, characterized in that The tread material of rail vehicle tires adopts a double-layer design, which consists 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, and the second tread adopts a low-heat generation formula design, with a heat generation coefficient range of 0.018~0.

026.

12. The rail vehicle tire according to claim 11, characterized in that The thickened position of the second tread covers the end point of the first belt layer, the end point of the second belt layer and the end point of the third belt layer. The thickness dimension h of the thickened position of the second tread ranges from h=3.5 to 5 mm. The horizontal distance W2 from the thickened position of the second tread to 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 7 mm. The thickness range of other positions of the second tread is 2 to 3.5 mm.

13. The rail vehicle tire according to claim 1, characterized in that The tread groove depth GD is 7.5~8.5mm.

Images