Electromagnetic Relay Press-Fit Assembly for Stable Contact Gap
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Solution Overview
Problem
Existing electromagnetic relays face challenges in maintaining consistent gaps between the shaft and movable elements when sealed with arc-extinguishing gas, leading to variations in product configuration and performance due to stress applied during the welding process of forming the closed space.
Innovation Solution
The electromagnetic relay design includes a press-fit fixing mechanism that adjusts the gap between the shaft and movable element before sealing, using a claw and recess system to set the gap to a predetermined size, and then seals the arc-extinguishing gas within the closed space, minimizing stress on the components during assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the gap between the shaft and movable element is adjusted after assembling the sealing member and inner cover, then the sealed space is already formed, but stress from subsequent processes may change the gap size leading to product variations
Solution Approach 1:
The gap between the shaft and movable element is adjusted to a predetermined size before the sealing member and inner cover are assembled. This preliminary adjustment ensures that the gap dimension is set while the structure is still accessible, preventing subsequent stress from welding or assembly processes from altering the gap, thus maintaining manufacturing precision without requiring complex post-adjustment mechanisms
Solution Approach 2:
The assembly process is segmented into distinct stages: first adjusting the gap between shaft and movable element, then assembling the sealing member and inner cover, and finally performing welding. This segmentation isolates the gap adjustment step from subsequent stress-inducing processes, ensuring gap consistency while maintaining a manageable assembly sequence
2Strength
If the claw portion and recess portion are press-fitted with large force, then the fixing is strong, but the gap between shaft and movable element may change
Solution Approach 1:
The gap between the shaft and movable element is adjusted to a predetermined size before the press-fitting operation. By performing this adjustment beforehand, the subsequent press-fitting process can apply sufficient force for strong fixing without concern for altering the gap, as the gap is already set in the previous step
Solution Approach 2:
The assembly process separates the gap adjustment step from the press-fitting step. The gap is adjusted first when components are still accessible, then the claw portion and recess portion are press-fitted with adequate force for strong fixing. This segmentation allows each operation to optimize for its specific purpose without compromising the other
3Reliability
If the gap between shaft and movable element varies, then the current cutoff performance deteriorates, but adjusting the gap requires additional manufacturing processes
Solution Approach 1:
The gap between the shaft and movable element is adjusted to a predetermined size before assembling the sealing member and inner cover. This preliminary adjustment ensures optimal current cutoff performance is achieved during the manufacturing process itself, eliminating the need for additional post-assembly adjustment processes and maintaining manufacturing efficiency
Solution Approach 2:
The gap adjustment operation is merged into the existing assembly sequence before sealing, rather than being a separate post-assembly step. This integration ensures reliable current cutoff performance is built into the manufacturing process flow, avoiding both performance variations and additional productivity losses from separate adjustment operations
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 approach reduces variations in the gap size between the shaft and movable element, enhancing current cutoff performance and reducing manufacturing costs by minimizing material usage and weight, while maintaining reliable sealing of the arc-extinguishing gas.
Implementation Method 1
a magnetizing coil which forms a magnetic field by energization
Implementation Method 2
A press-fit fixing portion which fixes the drive unit and the relay unit by press-fitting a claw portion provided on one of the yoke or the frame and a recess portion provided on the other one
Implementation Method 3
a return spring which urges the movable core in a direction away from the fixed core
Implementation Method 4
a contact pressure spring which urges the movable element to a side to the fixed terminal
Data Source
AI summary
A press-fit fixing portion fixes a drive unit and a relay unit by press-fitting a claw portion and the recess portion. A sealing member is provided on an outside of the relay unit and the drive unit. An inner cover forms a sealed space for sealing an arc-extinguishing gas together with the sealing member. An electromagnetic relay is configured to make it possible both an adjustment of a press-fitting amount of the claw portion and the recess portion and an adjustment of the gap between a ceramic insulator at an end of a shaft and a movable element by making each of the relay unit and the drive unit in a manufacturing process to the same state as in when a magnetizing coil is energized.