Switch Case High-Frequency Welding Release Region
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Solution Overview
Problem
In sealed switches, such as neutral start switches for vehicular automatic transmissions, the pressure increase during the jointing process causes grease to leak from the connector portion due to the imperfect adhesive state between conductive-metallic fixed contact points and plastic substrates, leading to exposure of the grease to high pressure within the switch case.
Innovation Solution
A switch design incorporating a release region in the jointing process between the substrate and lid body, where a notch in the projecting portion allows for air escape and pressure equalization, preventing grease leakage by maintaining communication between the inside and outside until the seal ring contacts the seal surface, thus suppressing pressure within the switch case.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the substrate and lid body are jointed by welding with high pressure to ensure strong joint strength and sealing, then the joint strength and sealing integrity are improved, but the grease leaks from the connector portion due to pressure increase
Solution Approach 1:
A release region is formed in advance in one of the substrate or lid body before the welding process. This release region allows air and grease to escape during the welding process, preventing pressure buildup that would cause grease leakage from the connector portion, while still enabling strong joint formation.
Solution Approach 2:
The harmful factor (grease and air pressure) is extracted from the system by providing a dedicated escape path through the release region. This allows the welding process to proceed with high pressure for strong joints without the harmful side effect of grease leakage from the connector.
2Reliability
If the switch case is sealed to prevent water and mud ingress, then the protection against external contaminants is improved, but the pressure during jointing has no release path causing grease leakage
Solution Approach 1:
The release region is prepared in advance before sealing occurs. During the welding process, this pre-formed region provides an escape path for air and grease, preventing pressure buildup. After welding completes and the seal is formed, the release region is no longer needed as the seal is already established.
Solution Approach 2:
The temporary opening (release region) that seems to compromise sealing is actually beneficial during the welding process by allowing pressure release. Once welding is complete, the seal ring forms the permanent seal, and the release region's temporary function has served its purpose of preventing grease leakage during the critical jointing phase.
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 solution effectively prevents grease leakage and ensures a strong, sealed joint between the substrate and lid body, maintaining the sealing integrity of the switch case while preventing water or mud ingress.
Implementation Method 1
high-frequency welding causes melting of the interference portion, so that the projecting portion 40 and the side wall 12 are jointed along the entire circumference
Data Source
AI summary
The concave streak portion 26, in which the welding inclination surface 27 is formed, is provided on the side wall 12; the projecting portion 40, which is fitted into the concave streak portion 26 when the substrate 10 and the lid body 35 overlap to form the switch case 3, is provided on the lid body 36; when the substrate 10 and the lid body 35 are overlapped, the switch case 3 is sealed by contacting the seal ring 31 with the flange portion 38 and the welding shoulder portion 41 interferes with the welding inclination surface 27; the substrate 10 and the lid body 35 are jointed by melting the interference portion by high-frequency welding; the release region K, which keep the communicating state of the inside of the switch case 3 with the outside is designed by notching the projecting portion 40 from the root thereof.