Hollow Coil Spring End Sealing to Prevent Corrosion and Clearance
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Solution Overview
Problem
Conventional hollow coil springs face issues with inner surface corrosion and product appearance deterioration due to incomplete sealing and gasification of coating materials during the manufacturing process.
Innovation Solution
The method involves an end sealing step where the core material of the hollow spring member is machined to seal both ends before the coil forming step, preventing clearance and ensuring a tight seal, even when gripped by a chuck, thus preventing corrosion and coating material entry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ends of hollow spring are sealed using resin in final step, then sealing is achieved, but inner surface corrosion occurs and product appearance deteriorates
Solution Approach 1:
The end sealing step is performed before the coil forming step and other subsequent steps. By gathering core material of the end of hollow spring member by machining to seal the ends in advance, the invention prevents inner surface corrosion and coating material gasification from occurring during subsequent processing steps.
Solution Approach 2:
The invention replaces the chemical sealing method (resin coating) with a mechanical sealing method (gathering core material by machining). This mechanical approach creates a physical barrier that prevents corrosion and gasification issues associated with resin-based sealing.
2Reliability
If lid members are separately provided and welded or screwed to ends, then sealing is achieved, but clearance forms between lid member and end during coil forming
Solution Approach 1:
The invention merges the sealing function with the spring member itself by gathering core material of the end of the hollow spring member. This eliminates the need for separate lid members and their associated fastening mechanisms, thereby preventing clearance formation during coil forming while maintaining sealing effectiveness.
3Weight of moving object
If hollow coil spring is used to reduce vehicle weight, then weight reduction is achieved, but inner surface corrosion and coating material gasification occur during manufacturing
Solution Approach 1:
The end sealing step is performed early in the manufacturing process, before coil forming and coating steps. This preliminary sealing prevents inner surface corrosion and coating material gasification during subsequent processing, enabling the use of hollow coil springs for weight reduction without suffering from manufacturing defects.
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 prevents inner surface corrosion, improves product appearance by eliminating dripping, and allows the hollow coil spring to be handled similarly to solid coil springs, with enhanced design advantages and stress resistance.
Implementation Method 1
ends by which core material of an end of a hollow spring member is gathered by machining
Data Source
Figure 1
Figure 2~3
AI summary
A hollow coil spring and a method for manufacturing therefor can prevent corrosion at an inner surface and can improve product appearance. In an end sealing step, an end Wa is sealed by which the core material of the end Wa of a spring member W is gathered by machining. It is preferable that spinning be carried out as a machining. For example, a squeezing roller R is moved in an axial direction as necessary, while the end of the spring member W is pressed to the inside in a radial direction by the squeezing roller R. As a result, the end Wa of the spring member W is sealed as shown in Fig. 3, and therefore, it is not necessary to use another member such as a lid member. For example, the end sealing step can be immediately carried out after an inner surface processing step. In a coil forming step after the end sealing step, formation of clearance can be prevented at the end Wa, even if the end Wa of the spring member W is gripped and the spring member W is wound around the rod.