Dual Spring Magnetic Switch Noise Reduction
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Solution Overview
Problem
Magnetic switches generate significant noise due to the lengthy nonlinear interval in contact pressure variation during the contact operation of the movable contactor, which can lead to contact damage and electrical incidents, especially in home and electric vehicle applications.
Innovation Solution
A sealed cased magnetic switch design incorporating a first contact pressure spring with one end supported by the movable contactor and the other end by a spring seat on the driving shaft, and a second contact pressure spring with a larger diameter supported by the movable contactor and an iron plate, applying elastic force radially to reduce noise by shortening the nonlinear interval of total contact pressure variation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a contact pressure spring with high elastic force is used to ensure operational reliability, then contact reliability is improved, but impact noise increases due to severe impact during contact operation
Solution Approach 1:
The single contact pressure spring is divided into two separate contact pressure springs with different characteristics. The first contact pressure spring (inner) has smaller diameter and provides initial contact pressure, while the second contact pressure spring (outer) has larger diameter and provides additional contact pressure. This segmentation allows the contact pressure to be applied in stages, reducing impact noise while maintaining reliability.
Solution Approach 2:
Different contact pressure springs are positioned at different radial locations to apply contact pressure at different stages. The first contact pressure spring applies pressure at the inner radius while the second contact pressure spring applies pressure at the outer radius. This local differentiation optimizes the contact pressure distribution throughout the contact operation, reducing the nonlinear interval and impact noise.
2Length of moving object
If the stroke of the movable contactor is increased, then the contact operation range is improved, but the nonlinear interval of contact pressure increases causing more severe noise
Solution Approach 1:
The contact pressure application is segmented into two stages using two different contact pressure springs. As the movable contactor moves through its stroke distance, the first contact pressure spring maintains contact pressure during the initial phase, and the second contact pressure spring engages to maintain pressure during the later phase. This segmentation ensures continuous contact pressure throughout the entire stroke, reducing the nonlinear interval and associated noise.
Solution Approach 2:
The dual contact pressure spring arrangement ensures continuous contact pressure application throughout the entire stroke distance of the movable contactor. The first and second contact pressure springs work in sequence to maintain uninterrupted contact pressure, eliminating the nonlinear interval where pressure would otherwise be stationary, thereby reducing noise throughout the continuous operation.
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 design effectively reduces noise generation by distributing the contact pressure more evenly, absorbing impact and minimizing stress on the movable contactor, thus preventing damage and noise during contact operations.
Implementation Method 1
a first contact pressure spring having one end supported by the movable contactor and applying an elastic force to the movable contactor to provide a contact pressure in a direction in which the movable contactor is brought into contact with the fixed electrode
Implementation Method 2
by moving the movable core by using magnetic force of a coil magnetized or demagnetized according to supply or interruption of control electric power source
Data Source
Figure 1~2
Figure 3
AI summary
A sealed cased magnetic switch comprises: a first contact pressure spring (23) having one end supported by the movable contactor and applying an elastic force to the movable contactor to provide a contact pressure in a direction in which the movable contactor is brought into contact with the fixed electrode; a spring seat member (25) supporting the other end of the first contact pressure spring and fixedly installed on the driving shaft; and a second contact pressure spring (24) having a diameter larger than that of the first contact pressure spring and applying an elastic force at an outer position in a radial direction compared with the first contact pressure spring to the movable contactor in a direction in which the movable contactor is brought into contact with the fixed electrode.