Bead durability evaluation method for heavy duty tires

An evaluation method and durability technology, applied in the direction of automobile tire testing, etc., can solve the problems of large unbalance test, damage to the bead part, and long test time

Active Publication Date: 2016-09-07
SUMITOMO RUBBER IND LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Hence the question: if Image 6 As shown in (A), ply end peeling occurs starting from the turn-up end ae of the carcass ply a constituting the tire frame, and the bead portion b is damaged
Therefore, it becomes an unbalanced test in which the deformation in the piercing direction at the turn-up end ae becomes too large compared to the deformation in the stretching direction, and there is a possibility that the structural bead produced in actual use cannot be realized. problem of adequate reproduction of damage
In addition, there are also problems in that the accuracy of durability evaluation such as errors in travel distance and travel time is poor, and the time required for the test is long.

Method used

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  • Bead durability evaluation method for heavy duty tires
  • Bead durability evaluation method for heavy duty tires
  • Bead durability evaluation method for heavy duty tires

Examples

Experimental program
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Effect test

Embodiment

[0066] In order to confirm the effect of the present invention, with figure 2 A commercially available heavy-duty tire (12.00R20-16PR) having the structure shown was used as a test tire, and a bead durability test was performed according to the specifications shown in Table 1, and the travel time until the bead portion was damaged was measured. In addition, a bead durability test was performed on four tires under each condition, and the average value and error σ of the travel time were compared.

[0067] The standard internal pressure P of the test tire 0 is 7.25kPa, standard load F 0 It is 30.5kN. Incidentally, the occurrence of damage to the bead portion is performed visually by an inspector, and when a change in appearance such as swelling or cracks occurs in the bead portion, it is determined that damage has occurred. In addition, "x" in the table means that the parts other than the bead part were damaged first, and the bead durability test could not be carried out to ...

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PUM

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Abstract

A rire bead durability evaluation method for a heavy duty tire comprises: a travelling step for test tires traveling on a cylinder; and an evaluation step for evaluating travel distance or travel time of producing damage as the tire bead durability. In the travelling step, an internal pressure P is 160-260% of a standard internal pressure (P0), a load (F) is 350-450% of a standard load (F0), a traveling speed V is 15-40 km / h, and the tire section height H of a tire in the pressing test is of more than 87.5% of the tire section height (H0) in the standard internal pressure-normal load state. In the evaluation step, when the elongation of exposed surface curve length of the tire lining rubber before and after the travelling is over 115%, the durability of the tire bead is not evaluated. By using the present invention, the durability of the tire bead can be accurately evaluated with a short test time.

Description

technical field [0001] The present invention relates to a method for evaluating the bead durability of a heavy-duty tire that can accurately evaluate the bead durability of a heavy-duty tire within a short test time. Background technique [0002] Heavy-duty tires are used under severe conditions where the air pressure is high and the load is large. Hence the question: if Figure 6 As shown in (A), ply end peeling occurs starting from the turn-up end ae of the carcass ply a constituting the tire frame, and the bead portion b is damaged. [0003] Specifically, in a heavy-duty tire, since the internal pressure is high, a large tension acts on the main body portion a1 of the carcass layer a spanning between the bead cores c, c. Therefore, the turn-up portion a2 of the carcass layer a is forcibly stretched toward the bead core c side, and as a result, the turn-up end ae is deformed in the pulling direction corresponding to the surrounding rubber. [0004] In addition, in heavy ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01M17/02
Inventor 李庆茂
Owner SUMITOMO RUBBER IND LTD
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