Rotary Switch Contact Structure to Suppress Abrasion Powder
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Solution Overview
Problem
Rotary switch devices experience performance deterioration due to long-term use, primarily caused by abrasion powder generation leading to short circuits and contact failure, especially under high current specifications.
Innovation Solution
The rotary switch device incorporates a movable contact member with a contact protrusion and surface that slides on a support portion, reducing contact area and preventing abrasion, while maintaining a non-contact state with the fixed contact member, and features corrosion-resistant conductive processing to prevent wear and corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the movable contact member slides on the fixed contact member, then conduction is established, but abrasion powder is generated causing short circuits and contact failure
Solution Approach 1:
The patent divides the contact path into two separate segments: a support portion for sliding contact and a fixed contact member for conduction. The movable contact member has a first contact portion that slides on the support portion and a second contact portion that contacts the fixed contact member, separating the sliding function from the conduction function to prevent abrasion powder generation during conduction.
Solution Approach 2:
The support portion acts as an intermediary element between the movable contact member and the fixed contact member. It receives the sliding contact from the movable contact member's first contact portion and transfers the movement, preventing direct sliding contact between the movable and fixed contact members, thereby eliminating abrasion powder generation.
2Reliability
If the contact portion is in a floating state, then wear is reduced, but the contact surface must always be in pressure contact causing sliding and abrasion
Solution Approach 1:
The movable contact member is segmented into a first contact portion for sliding contact with the support portion and a second contact portion for conduction with the fixed contact member. This segmentation allows the second contact portion to remain in a floating state during movement, reducing wear, while the first contact portion handles the sliding contact separately.
Solution Approach 2:
The sliding contact function is extracted from the conduction contact portion. The first contact portion is specifically designed to slide on the support portion, while the second contact portion is extracted to only perform conduction without sliding, maintaining a floating state to reduce wear and prevent abrasion powder generation.
3Reliability
If an anticorrosive film is formed on the contact surface, then corrosion is prevented, but the film peels off due to abrasion powder causing contact failure
Solution Approach 1:
The support portion serves as an intermediary that prevents direct sliding contact between the movable contact member's contact surface and the fixed contact member. By introducing this intermediary sliding surface, the anticorrosive film on the conduction contact surface is protected from abrasion-induced peeling, maintaining both corrosion resistance and film integrity.
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 design effectively suppresses abrasion powder generation, prevents contact damage, and ensures reliable operation under both low and high current specifications without the need for multiple rotary switches, maintaining high connection reliability over time.
Implementation Method 1
The movable contact member 6 slides on the support portion 8 with the edge corner portion 7 as a sliding contact portion
Data Source
AI summary
A rotary switch device includes a terminal base to which a center portion contact and a fixed contact member are fixed, a movable contact member which includes a contact protrusion part being in pressure contact with the center portion contact at one end and a contact surface with the fixed contact member at the other end, and is operated to rotate around the center portion contact so as to short-circuit between the center portion contact and the fixed contact member at a conductive rotation position, and a support portion which is formed in the terminal base and supports an edge corner portion along a rotation direction when the contact surface of the movable contact member is operated to rotate. The movable contact member slides on the support portion with the edge corner portion as a sliding contact portion and moves to the conductive rotation position where the contact surface is in contact with the fixed contact member.