Shock Absorber Bumper Cap Structure for Molded Hole Durability
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Solution Overview
Problem
The durability of bumper caps in shock absorbers is a concern.
Innovation Solution
The bumper cap is designed with a configuration that includes a lid portion, a cylindrical portion, and a communication hole, where the edge of the communication hole is narrower on the downstream side during molding, and incorporates inclined portions to enhance structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the bumper cap is formed by conventional molding methods with a standard communication hole, then the manufacturing process is simple, but the durability and structural integrity are insufficient
Solution Approach 1:
The communication hole is designed with non-uniform thickness, being thinner at the downstream end and thicker at the upstream end. This local variation in quality optimizes the structural integrity and durability of the bumper cap while maintaining manufacturability through conventional molding methods.
Solution Approach 2:
The communication hole incorporates curved or inclined surfaces rather than sharp edges, with the hole being formed at an angle relative to the molding direction. This curvature reduces stress concentration points and improves the overall durability of the bumper cap structure.
2Strength
If the communication hole edge is made narrower at the downstream end, then the structural connection is stronger, but the molding process becomes more difficult
Solution Approach 1:
The communication hole is designed with varying thickness parameters along its length, being thinner at the downstream end and thicker at the upstream end. This parameter variation optimizes structural strength while the inclined surfaces ensure the hole can still be formed using conventional molding techniques.
Solution Approach 2:
The mold design incorporates the inclined surfaces and varying thickness of the communication hole from the beginning of the molding process. This preliminary action ensures that the material flows and solidifies in the desired configuration, achieving both strength and manufacturability without requiring post-processing.
3Reliability
If the communication hole has uniform thickness, then the manufacturing is easier, but the durability and resistance to wear are reduced
Solution Approach 1:
The communication hole is designed with non-uniform thickness, being thinner at the downstream end and thicker at the upstream end. This local variation in quality optimizes the structural integrity and durability of the bumper cap while maintaining manufacturability through conventional molding methods.
Data Source
AI summary
A bumper cap is used for a shock absorber. The shock absorber includes a cylinder, a piston and piston rod. The bumper cap is at an end part of the cylinder on a side from which the piston rod extends and is formed by die casting or injection molding, and includes a lid coming into contact with an axial end surface of the cylinder and having a through hole through which the piston rod is inserted. A cylindrical portion has a cylindrical shape provided radially outward from the through hole and an outer circumferential surface of the cylinder. A communication hole in the cylindrical portion permits communication between inner and outer circumferential surfaces of the cylindrical portion. An edge of the communication hole is narrower on the first end part side positioned downstream than at the second end part positioned upstream through which a material flows in during molding.