Tire Inner Mold Segments with Elastic Butting Members
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Solution Overview
Problem
The rigid inner mold method for tire formation faces issues with the generation of radial steps between inner mold segments due to thermal expansion, which affects tire uniformity, and the existing solutions to mitigate this problem either increase the risk of rubber sticking or compromise tire quality.
Innovation Solution
Incorporating butting members with a Young's modulus smaller than the inner mold segments, which are fixed to the circumferential ends of these segments, to absorb thermal expansion pressures and maintain disassembly efficiency while preventing rubber sticking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the interspace amount between mating surfaces is increased to reduce pressing force during vulcanization, then the radial step between inner mold segments is reduced, but rubber sticking occurs as rubber flows into the interspace
Solution Approach 1:
A butting member is introduced as an intermediary element between the first and second inner mold segments. This butting member has a smaller Young's modulus than the segments, allowing it to elastically deform and absorb thermal expansion forces during vulcanization, thereby preventing direct contact and rubber flow between the mating surfaces of the segments while maintaining structural integrity
Solution Approach 2:
The Young's modulus of the butting member is specifically designed to be smaller than that of the inner mold segments. This parameter change allows the butting member to exhibit greater elasticity and deformability under thermal expansion conditions, enabling it to absorb pressing forces without creating gaps large enough to cause rubber sticking
2Ease of operation
If the inner mold body is divided into multiple segments to enable extraction, then disassembly and removal become possible, but thermal expansion during vulcanization causes pressing forces that generate radial steps between segments
Solution Approach 1:
The butting member serves as a mediator between adjacent inner mold segments, absorbing thermal expansion forces through its elastic deformation. This prevents the segments from pushing against each other and generating radial steps, thereby maintaining tire uniformity while preserving the segmented structure's disassembly capability
Solution Approach 2:
The inner mold body is constructed as a composite structure combining rigid segments with a more elastic butting member. This composite design allows the segments to maintain structural integrity for disassembly while the butting member provides flexibility to accommodate thermal expansion without compromising tire uniformity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively reduces the radial step between inner mold segments, enhances tire uniformity, and maintains the disassembly efficiency of the inner mold body while minimizing rubber sticking during vulcanization.
Implementation Method 1
a temperature of the inner mold body (a) rises from an ordinary temperatures state at a time of the green tire formation (about from 15 to 50 °C) to a high temperature state at a time of vulcanization (not less than 100 °C). Therefore, at the time of vulcanization, thermal expansion causes a pressing force between the inner mold segments c1 and c2
Implementation Method 2
Young's modulus Ea of the butting members is smaller than Young's modulus Eb of the first and second inner mold segments
Data Source
Figure 1
Figure 2(A)~2(B)
Figure 3(A)~3(B)
AI summary
Provided is a rigid core for tire formation that limits the rubber stuck between inner mold segments in an inner mold segment while mi ni mi zi ng the occurrence of unevenness in the radial direction between inner mold segments that is caused by thermal expansion. A core main body 2 is divided into: a first inner mold segment 5A in which both circumferential end surfaces 5As are inclined radially inward in a di recti on in which the circumferential width increases; a second inner mold segment 5B that is arranged in an alternating manner with the inner mold segment 5A and in which both circumferential end surfaces 5Bs are inclined radially inward in a direction in which the circumferential width decreases; and a butting member 6 that is arranged between the fi rst inner mold segment 5A and the second inner mold segment 5B. Young's modulus Ea of the butting member 6 is smaller than Young's modulus Eb of the first and second inner mold segments 5A and 5B.