Motorcycle Head Box Stiffness via Molded Communication Hole
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Solution Overview
Problem
Existing motorcycle head box structures struggle to balance stiffness and air-intake noise reduction, as the communication hole in the head box is exposed and formed by cutting the separating wall after molding, which complicates the manufacturing process and affects the structural integrity.
Innovation Solution
A method of molding the head box with a communication hole formed using a convex portion of the forming dies, allowing for reduced work steps and improved flexibility in molding, where the forming dies are broken into small pieces after molding, enabling the creation of a structure that enhances stiffness while reducing air-intake noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the communication hole is formed by cutting the separating wall after molding, then the head box can be manufactured, but the manufacturing process becomes complex and the structural integrity is compromised
Solution Approach 1:
The communication hole is formed during the molding process itself by using a convex portion on the forming die that protrudes into the mold cavity. This preliminary action eliminates the need for subsequent cutting operations, simplifying the manufacturing process while maintaining structural integrity.
Solution Approach 2:
The formation of the communication hole is merged with the molding process. The convex portion of the forming die simultaneously creates both the separating wall and the communication hole in a single operation, reducing the number of manufacturing steps.
2Strength
If the communication hole is formed by cutting the separating wall after molding, then the head box can be manufactured, but the exposed communication hole reduces stiffness
Solution Approach 1:
The convex portion is designed in advance on the forming die to create the communication hole with the correct dimensions and positioning during molding. This preliminary design allows the extending section to properly cover the communication hole, improving stiffness while maintaining manufacturing flexibility.
Solution Approach 2:
The extending section is designed to locally cover the communication hole area, providing enhanced stiffness specifically where needed without affecting the overall manufacturing flexibility of the head box structure.
3Productivity
If the forming dies are kept intact after molding, then the process is simple, but the communication hole cannot be formed without considering drafts
Solution Approach 1:
The forming die is segmented into removable parts, with the convex portion being a separate component that can be detached after molding. This segmentation allows the convex portion to be reused for creating communication holes in different positions and configurations, enhancing molding flexibility while maintaining productivity.
Solution Approach 2:
The convex portion is temporarily attached to the forming die during the molding process to create the communication hole, then discarded or recovered after use. This approach allows for versatile communication hole formation without permanently complicating the die structure.
Data Source
AI summary
An air-intake device comprises a vehicle body frame including a head box; and a pair of right and left main frames, wherein the head box includes: a casing section which extends between a front opening and a rear opening of the head box and is formed with a main air passage; and a pair of right and left extending sections coupled to the pair of main frames, respectively, wherein at least one extending section is provided with a branch air passage which branches from the main air passage, and wherein a separating wall is provided between the main air passage and the branch air passage and has a communication hole, and wherein when a vehicle body is viewed from a side, at least one extending section is extended rearward to a location at which at least a front region of the communication hole is covered by the extending section.