Hollow Spring Inner Surface Blasting Method
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Solution Overview
Problem
Conventional methods for abrasive blasting of hollow coil springs, particularly those with small diameters and lengths, are inefficient and unsuitable for mass production due to surface defects and uneven grinding, which affect the durability and surface roughness of the inner surfaces.
Innovation Solution
An improved abrasive blasting method where abrasives are ejected and suctioned from both ends of the spring material, with controlled ejection and suction pressures, particle sizes, and processing times to prevent trumpet-shaped surfaces and ensure uniform grinding, allowing for the reduction of surface roughness to 20µm or less.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a belt with abrasive paper is inserted into the spring member for inner surface polishing, then the inner surface defects can be removed, but the processing time becomes too long and mass production is not suitable
Solution Approach 1:
The patent replaces the mechanical belt polishing system with a pneumatic abrasive blasting system. Compressed air propels abrasives through the spring member to achieve inner surface polishing without the mechanical complexity and time consumption of belt insertion and reciprocation, thereby improving both surface quality and production efficiency
Solution Approach 2:
The patent uses compressed air (pneumatics) to propel abrasives through the spring member for inner surface blasting. This pneumatic approach enables rapid material removal and surface finishing without mechanical contact, significantly reducing processing time while maintaining or improving surface roughness quality
2Device complexity
If abrasives are ejected from only one end portion of the spring member, then the blasting process is simple, but the inner surface develops a trumpet shape due to uneven grinding
Solution Approach 1:
The patent applies asymmetric blasting by ejecting abrasives from one end while suctioning from the other, creating a controlled flow pattern that prevents trumpet shape formation. This asymmetric approach balances the grinding forces along the spring member length, achieving uniform inner surface finishing without increasing overall process complexity
Solution Approach 2:
The patent inverts the conventional single-end blasting approach by using opposite-direction ejection and suction. Instead of ejecting from both ends simultaneously, it ejects from one end and suctiones from the other, reversing the expected flow pattern to achieve uniform material removal and prevent trumpet shape deformation
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 method enhances the durability and efficiency of inner surface abrasive blasting, enabling mass production of hollow springs with uniform surface finishing and reduced defects, improving the overall quality and durability of the springs.
Implementation Method 1
the blasting is performed in which the abrasives are ejected to the inner surface of the spring material and are suctioned, so that the inner surface of the spring material is ground
Implementation Method 2
a compressed air is supplied into the pressure application tank, so that the inside of the pressure application tank is pressurized by the compressed air
Data Source
AI summary
A hollow spring and a production method therefor, which can improve the durability and the efficiency of inner surface abrasive blasting for spring material, are provided. A straight-shaped hollow spring material W is used in a blasting apparatus 100. The length of the spring material W is set to be 1.5 m to 3.5 m, and the inner diameter of the spring material W is set to be not more than 10 mmϕ (not including 0). In inner surface abrasive blasting for the spring material W, first blasting and second blasting are performed in turn. In the first blasting, abrasives are ejected to an opening portion Wa of the spring material W and are suctioned from an opening portion Wb thereof. In the second blasting, the abrasives are ejected to the opening portion Wb of the spring material W and are suctioned from the opening portion Wa thereof. Thus, the inner surface of the spring material W can be prevented from having a trumpet shape. The ejection pressure, the suction pressure, and the like are appropriately set, so that generation of grinding amount difference between the center portion and both end portions of the inner surface of the spring material W can be inhibited.