Movable Contact Recess Structure for Quiet Electromechanical Switching
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Solution Overview
Problem
Electromechanical switches in applications like electric vehicles generate audible noise and excessive thermal energy due to current surges when the movable contact engages with stationary contacts, causing discomfort and potential damage.
Innovation Solution
The design includes a movable contact with separate contact zones and recesses that allow the stationary contacts to engage on opposite sides of the recess, reducing noise and thermal energy by distributing the contact area and mass closer to the mounting side, thereby minimizing oscillation and heat generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the movable contact is rapidly engaged with the stationary contacts to accelerate current flow, then the vehicle acceleration response is improved, but audible noise and thermal energy generation increase
Solution Approach 1:
The movable contact is divided into multiple contact zones (first contact zone, second contact zone, etc.) that engage with stationary contacts sequentially or simultaneously. This segmentation distributes the current flow across multiple interfaces, reducing the concentration of thermal energy and mechanical stress at any single contact point, thereby reducing audible noise and thermal generation while maintaining fast response
Solution Approach 2:
Different contact zones are positioned at different locations on the movable contact with varying geometries and materials optimized for their specific functions. The recesses create localized regions that control current distribution and thermal management, allowing each contact zone to handle specific portions of the current surge differently to minimize overall noise and heat generation
2Object-generated harmful factors
If the movable contact has large mass to reduce oscillation, then noise reduction is improved, but the switching speed and response time deteriorate
Solution Approach 1:
The movable contact is segmented into multiple zones with varying mass distribution. The recesses create localized mass variations that reduce oscillation in specific areas without requiring a uniform increase in overall mass. This allows the contact to have sufficient damping in critical regions while maintaining lightweight characteristics for fast switching response
Solution Approach 2:
The recesses are positioned asymmetrically or with specific depth variations to create non-uniform mass distribution that strategically dampens oscillation. By placing more mass in specific regions (through recess depth variations), the design targets oscillation reduction at contact interfaces without adding excessive overall mass that would slow switching response
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 configuration significantly reduces audible noise and thermal energy within the contacts, enhancing operational comfort and reducing wear and damage from heat in electric vehicle applications.
Implementation Method 1
a large amount of thermal energy may be generated within the contacts that has undesirable effects
Implementation Method 2
This surge of current may cause the movable contact to oscillate and generate the audible noise
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
Electromechanical switch (102) includes first and second stationary contacts (204, 206). Each of the first and second stationary contacts (204, 206) has a respective mating end. The electromechanical switch (102) also includes a movable contact (300) having first and second contact zones (330, 332). The first and second contact zones (330, 332) are separate regions of the movable contact (300) that are operable to be covered by the respective mating ends of the first and second stationary contacts (204, 206), respectively. Each of the first and second contact zones (330, 332) has a mating surface (334) and a corresponding recess (336) that divides at least a portion of the mating surface (334). Each of the respective mating ends is configured to extend across the corresponding recess (336) and engage the corresponding mating surface (334) on opposite sides of the corresponding recess (336). The corresponding recess (336) has a depth (338) that extends only partially into the movable contact (300).