Rotary Switch Concentric Contact Arrangement
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Solution Overview
Problem
Existing rotary switches face issues with deteriorating connection and disconnection performance over time due to abrasion powder generation, which affects insulation properties and contact reliability, especially under high current specifications where the interval between fixed contacts becomes narrower.
Innovation Solution
A rotary switch design with a power supply terminal at the rotation center and fixed contacts on concentric circles of varying diameters, where each movable contact is dedicated to a specific fixed contact, ensuring uniform wear and using concave portions to collect abrasion powder, maintaining a sufficient insulating space and preventing insulation failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the power supply terminal is disposed around the rotation center with a long arcuate length to maintain contact state, then the contact reliability is improved, but the disposition space of fixed contacts becomes narrower
Solution Approach 1:
The patent transitions from a two-dimensional arcuate arrangement to a three-dimensional concentric circular arrangement. Fixed contacts are disposed on multiple concentric circles with different diameter dimensions, allowing contacts to be positioned in radial and angular directions simultaneously. This dimensional expansion resolves the space constraint while maintaining contact reliability.
2Quantity of substance
If the interval between adjacent fixed contacts is narrowed to accommodate more contacts, then the quantity of contacts is increased, but the insulation property deteriorates due to abrasion powder scattering
Solution Approach 1:
By arranging fixed contacts on multiple concentric circles with different diameter dimensions, the patent increases the angular separation between adjacent contacts. This spatial distribution on multiple circular paths prevents abrasion powder from easily scattering between contacts, maintaining insulation properties while accommodating more contacts.
Solution Approach 2:
The concentric circular arrangement creates nested circular paths for fixed contacts. Each circle is positioned at a different radial distance from the rotation center, creating a nested structure that maximizes the use of available space while maintaining adequate insulation distances between contacts on different circles.
3Stability of the object's composition
If fixed contacts are formed to be elongated in circumferential direction for error absorption and contact cleaning, then the contact stability is improved, but the interval between adjacent fixed contacts becomes narrower
Solution Approach 1:
The patent compensates for the space consumed by elongated fixed contacts by utilizing the radial dimension. Contacts on different concentric circles are separated by radial distance, allowing each contact to be elongated in the circumferential direction without significantly reducing the effective interval between adjacent contacts on different circles.
Data Source
Figure 1
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AI summary
A rotary switch 6 includes a movable conductor held in a rotation movable portion; a power supply terminal held in a base portion; and a fixed contact, in which the fixed contact and the power supply terminal are connected and disconnected via the movable conductor by a rotational operation to the rotation movable portion, in which the power supply terminal is disposed at a rotation center position of the rotation movable portion, and in which a plurality of fixed contacts are disposed on a plurality of concentric circles around the power supply terminal.