Non-Pneumatic Tire Insert Molding to Prevent Tread Separation
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Solution Overview
Problem
The manufacturing process for non-pneumatic tires requires jigs and tools for surface treatment and adhesive application, increasing costs, and insert-molding with a tread member as an insert material leads to separation of the ring member from the tread member during cooling.
Innovation Solution
A method involving insert-molding a ring member with a tread member using a molding die configuration where the tread member expands outward during resin filling, followed by controlled shrinkage to adhere to the ring member, preventing separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If surface treatment and adhesive application are used to attach the tread member to the ring member, then the adhesion between components is improved, but the manufacturing complexity and cost increase due to requiring multiple jigs and tools
Solution Approach 1:
The patent combines the tread member attachment and ring member formation into a single insert-molding operation. The tread member is placed as an insert in the mold cavity, and molten resin is injected to form the ring member around it, integrating two separate manufacturing steps (surface treatment + adhesive application, or separate molding + attachment) into one simultaneous process, thereby reducing the number of jigs and tools required
Solution Approach 2:
The molten resin automatically adheres to the tread member surface during the insert-molding process without requiring separate surface treatment or adhesive application steps. The resin's natural flow and cooling process create the bonding interface between the tread member and ring member, allowing the material itself to provide the adhesion function
2Stability of the object's composition
If the tread member outer diameter is made equal to or larger than the cavity inner diameter, then the tread member maintains its position during molding, but the ring member separates from the tread member during cooling due to shrinkage
Solution Approach 1:
The patent changes the dimensional parameter of the tread member outer diameter to be smaller than the cavity inner diameter. This parameter change allows the tread member to expand during resin filling while maintaining position stability, and subsequently shrink during cooling to adhere to the ring member, preventing separation
Solution Approach 2:
The patent utilizes thermal expansion and contraction of the tread member. During the hot resin filling process, the tread member expands outward to maintain contact with the cavity wall for position stability. During cooling, the tread member contracts and shrinks, creating adhesion to the ring member and preventing separation
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
The method stabilizes the insert-molding process, preventing separation of the ring member from the tread member and reducing manufacturing costs by ensuring adhesion and sealability.
Implementation Method 1
when pressurized molten resin is supplied into the cavity, the tread surface of the tread member expands outward in the tire radial direction
Implementation Method 2
the filled molten resin shrinks when cooled, and the tread member, which had expanded outward in the tire radial direction, restores its original shape while following the shrinkage of the resin
Data Source
AI summary
A method for manufacturing a non-pneumatic tire that can suppress the separation of the ring member from the tread member is provided. The method for manufacturing a non-pneumatic tire according to this disclosure is a method for manufacturing a non-pneumatic tire that comprises: a ring member formed as a single piece, having an inner cylinder, an outer cylinder and a connecting member; and a tread member, including: inserting the tread member into a cavity, moving a movable-side die to close the cavity, and supplying molten resin to space on an inner side in the tire radial direction of the tread member and molding the ring member, and characterized in that an outer diameter of an outer circumferential surface (tread surface) of the tread member before molding the ring member is smaller than an inner diameter of an inner circumferential surface of the cavity that faces the outer circumferential surface.