Tire bead and light truck tire thereof

Abstract

The utility model provides a tire bead and a light truck tire thereof, the tire bead is provided with a tire bead contour, the tire bead contour is tightly attached to a tubeless rim, the tire bead contour comprises a circular arc R1 and a line segment AB which are matched with a rim flange, and the vertical height H from the circle center position of the circular arc R1 to a bead heel is 10.0%-11.5% of the height LSH of the lower section of the tire; the line segment AB and the arc R1 intersect at a point A, the point A and the circle center of the arc R1 are located on the same horizontal line, and the included angle theta between the line segment AB and the vertical direction is 2-4 degrees; the bead heel arc R2, the line segment CD and the line segment DE are sequentially arranged in the direction from the bead heel to the bead toe, and the bead heel arc R2 is tangent to the line segment AB and the line segment CD; and the ratio of the width L2 of the line segment DE to the width L1 of the line segment CD is 0.10-0.18. By optimizing the outline size of the tire bead, the suitability of the tire and the tubeless rim is improved, and the durability of the tire bead of the light truck tire is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to light truck tire technical field, concretely relates to a bead and its light truck tire. BACKGROUND

[0002] At present, most light trucks tend to assemble tubeless rims. This is because the tubeless rim reduces the overall weight of the vehicle compared to the traditional tube rim, which can reduce fuel consumption, but the rim height of the tubeless rim is relatively low, and there is a convex peak at the bead seat. These structural characteristics are significantly different from traditional tube rims.

[0003] However, past tire products are mostly designed based on tube rims, and the bead profile is well adapted to tube rims. However, when these tires are applied to tubeless rims, problems arise.

[0004] Due to the significant difference in profile size between tube rims and tubeless rims, such as the difference in rim height, bead seat width, and other key dimensions, the bead of the existing product cannot be well matched with the tubeless rim. In the actual assembly process, the bead profile and the rim cannot be closely fitted, which causes the bead to deform during use, the bead portion to be unevenly stressed, and further problems such as bead cracking and bead gap. SUMMARY

[0005] The technical problem to be solved by the utility model is to improve the adaptability of the tire to the tubeless rim to improve the durability of the bead.

[0006] In a first aspect, to solve the above technical problem, the utility model provides a bead, having a bead profile, the bead profile closely fits the tubeless rim, and the bead profile comprises:

[0007] An arc R1 and a line segment AB cooperating with the rim rim, the center of the arc R1 is located at a vertical height H from the heel, which is 10.0%-11.5% of the lower section height LSH of the tire; the line segment AB intersects the arc R1 at point A, and the A point and the center of the arc R1 are located on the same horizontal line, and the angle θ between the line segment AB and the vertical direction is 2°-4°;

[0008] A heel arc R2, a line segment CD and a line segment DE are sequentially arranged from the heel to the toe, the heel arc R2 is tangent to the line segment AB and the line segment CD respectively; the ratio of the width L2 of the line segment DE to the width L1 of the line segment CD is 0.10-0.18.

[0009] Further, the width W of the bead is 14%-16.5% of the rim fitting width TBW.

[0010] Further, the line segment DE located at the toe is designed as a platform structure.

[0011] Further, the bead seat of the tubeless rim is provided with a hump, and the pressure distribution of the line segment DE when contacting the hump is uniform.

[0012] The second aspect of the utility model provides a light truck tire, including the carcass, the carcass extends to the bead from the crown, the outermost layer of the carcass is equipped with the bead cover cloth, the bead is the bead described above.

[0013] Compared with the prior art, the utility model has the following beneficial effects:

[0014] The utility model discloses the optimization of bead contour size improves the adaptability of tire and tubeless rim, can reduce the deformation of framework material reverse package end point on one hand, and can optimize the contact pressure of bead and rim on the other hand to improve the bead endurance performance of tire. BRIEF DESCRIPTION OF DRAWINGS

[0015] Fig. 1 Partially cutaway view disclosed by the utility model embodiment shows the schematic diagram of tire lower section high LSH and rim fitting width TBW;

[0016] Fig. 2 The bead contour local structure schematic diagram disclosed by the utility model embodiment.

[0017] In the drawing: 10, carcass;20, bead cover cloth;30, bead contour. DETAILED DESCRIPTION

[0018] In order to make the technical scheme and technical effect of the utility model more clear, the technical scheme in the utility model embodiment will be described clearly and completely in the following with the drawings in the embodiment, obviously, the described embodiment is a part of the embodiment of the utility model, not all the embodiment.

[0019] The utility model aims at providing a new type of bead that optimizes the design of bead contour, for improving the adaptability between tire and tubeless rim, and then improving the endurance performance of tire bead.

[0020] Please refer to Figs. 1-2 The bead has a bead contour 30, and the bead contour 30 is closely combined with the tubeless rim.

[0021] The bead contour 30 includes five parts, which are circular arc R1 combined with the rim flange, line segment AB;Tread heel circular arc R2, line segment CD and line segment DE are sequentially arranged in the direction from the tread heel to the toe;The following is the main description.

[0022] The arc R1 and the line segment AB cooperate with the rim flange:

[0023] The vertical height H of the center of the arc R1 from the bottom of the tire is 10.0%-11.5% of the lower section height LSH of the tire.

[0024] If the vertical height H is too high or too low, the height difference with the rim flange part is large, which affects the matching with the rim.

[0025] The line segment AB intersects with the arc R1 at point A, and the center of the arc R1 and point A are located on the same horizontal line.

[0026] The angle θ between the line segment AB and the vertical direction is 2°-4°.

[0027] If θ>4°, the interference amount is large when assembling with the rim, which is easy to cause stress concentration at the bead part, thereby causing bead failure; if θ<2°, the matching with the rim is not close enough, which may cause bead deformation and other problems during use.

[0028] The bottom arc R2, the line segment CD and the line segment DE are sequentially arranged from the bottom to the toe of the tire:

[0029] The bottom arc R2 is tangent to the line segment AB and the line segment CD, respectively.

[0030] Since there is a convex peak at the bead seat of the rim without an inner tube, in order to avoid excessive stress concentration when the toe part cooperates with the convex peak of the rim, the line segment DE at the toe part is designed as a platform structure, which is beneficial to uniform distribution of pressure when the line segment DE contacts with the convex peak.

[0031] The ratio of the width L2 of the line segment DE to the width L1 of the line segment CD is 0.10-0.18.

[0032] The width W of the bead is 14%-16.5% of the rim fitting width TBW.

[0033] If the width W of the bead is too wide, the inner diameter at the toe part becomes small, which is easy to cause tire mounting difficulty; if the width W of the bead is too narrow, the matching with the bead seat of the rim is not close enough, thereby affecting the air tightness of the tire.

[0034] Through the above bead contour design, the adaptability of the tire and the rim without an inner tube can be effectively improved, the bead deformation is reduced, the shear strain and heat generation of the tire body are reduced, and the bead durability of the light truck tire is improved.

[0035] In order to prove the technical effect of the utility model, the following finite element analysis and test are carried out for verification.

[0036] The rim assembled in the finite element analysis and test of the embodiment and the comparative example is a standard rim without an inner tube of a corresponding specification.

[0037] The tire size used in the examples and comparative examples in Tables 1, 2, and 3 is 7.50R16LT.

[0038] Table 1

[0039]

[0040] It should be noted that the toe of the comparative example 1 in Table 1 is not designed with a platform.

[0041] Table 1 shows the shear strain and strain energy density at the bead filler end point of the tire carcass and bead cap under load by finite element analysis, and the endurance test of the solid tire is arranged on a machine.

[0042] The shear strain refers to the deformation in the plane formed by the cord direction and the perpendicular cord direction at the bead filler end point, and the smaller the value, the smaller the deformation and the better the bead endurance performance.

[0043] The strain energy density refers to the energy per unit area, and the greater the strain energy, the greater the energy at that location, the higher the heat generation, and the worse the bead endurance performance.

[0044] The bead endurance result index is an index of the actual machine test result, and the larger the value, the longer the tire running time and the better the bead performance.

[0045] As can be seen from the comparative examples and examples in Table 1, after optimization of the bead profile, the shear strain and strain energy density of the bead filler end point are reduced, and the bead endurance performance of the tire is improved.

[0046] Table 2

[0047]

[0048] As can be seen from Table 2, if the height H and the LSH ratio are too high or too low, the shear strain and strain energy density of the carcass and bead cap end point will increase significantly, but when within the recommended range, the shear strain and strain energy density fluctuate less.

[0049] Table 3

[0050]

[0051] As can be seen from Table 3, if the angle θ is outside the recommended range, the shear strain and strain energy density of the carcass and bead cap end point will increase significantly; when within the recommended range, the shear strain and strain energy density fluctuate less.

[0052] The examples and comparative examples in Table 4 use a tire size of 7.00R16LT.

[0053] Table 4

[0054]

[0055] It can also be seen from Table 4 that after the tire bead profile is optimized according to the application, the carcass reverse wrapping end point shear strain and strain energy density are reduced, and the tire bead durability is greatly improved.

[0056] The utility model discloses still protect a kind of light truck tire, including carcass 10, carcass 10 extends to bead from crown, the outermost layer of carcass 10 is equipped with bead cover cloth 20, wherein, the bead is above optimized bead.

[0057] Compared with the conventional bead profile of the existing tire, the utility model improves the adaptability of tire and tubeless rim by optimizing the bead profile size, which can reduce the deformation of the reverse wrapping end point of framework material on one hand, and optimize the contact pressure of the bead and the rim on the other hand, to improve the bead durability of tire.

[0058] Although the embodiments of the utility model have been shown and described, it can be understood by those skilled in the art that various changes, modifications, replacements and variations can be made to these embodiments without departing from the principles and spirits of the utility model, and the scope of the utility model is defined by the appended claims and their equivalents.

Claims

1. A bead having a bead contour (30) which fits tightly to a tubeless wheel rim, characterized in that The bead contour (30) comprises: an arc of a circle R1 matched with the rim flange, a center of the arc of a circle R1 being located at a distance of 10.0%-11.5% of a vertical height H at the heel to a lower section height LSH of the tire, the arc of a circle R1 intersecting with a line segment AB at a point A, the point A and a center of the arc of a circle R1 being located on a same horizontal line, and an included angle θ between the line segment AB and a vertical direction being 2°-4°; a heel arc R2, a line segment CD and a line segment DE arranged in sequence from the heel to the toe, the heel arc R2 being tangent to the line segment AB and the line segment CD respectively, and a ratio of a width L2 of the line segment DE to a width L1 of the line segment CD being 0.10-0.

18.

2. The bead of claim 1, wherein, A width W of the bead is 14%-16.5% of a rim fitting width TBW.

3. The bead of claim 1, wherein, The line segment DE at the toe is designed as a platform structure.

4. The bead of claim 3, wherein, The bead seat of the tubeless rim is provided with a convex peak, and a pressure distribution of the line segment DE when contacting with the convex peak is uniform.

5. A light truck tire comprising a carcass (10) extending from a crown to a bead, the outermost layer of said carcass (10) being provided with a bead chafer (20), characterized in that, The bead is the bead according to any one of claims 1-4. The tire is the tire according to any one of claims 1-5.

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