Electromagnetic Switching Device Shaft Stepped Structure
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Solution Overview
Problem
The existing electromagnetic switching devices suffer from rapid wear and damage at the welded joint between the movable core and shaft due to repeated upward and downward motion, leading to reduced endurance.
Innovation Solution
The design includes a shaft with a large and small diameter portion and a stepped surface, where the return spring presses the shaft downward, and the movable core is coupled with the shaft without welding, allowing the shaft to press the core downward, reducing the stress on the joint and preventing damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the movable core and shaft are welded together to ensure firm connection, then the connection strength is improved, but the welded part is damaged rapidly due to repeated repulse force and collision impact, reducing the device lifespan
Solution Approach 1:
The shaft is segmented into a large diameter portion and a small diameter portion, creating a stepped structure. The movable core fits onto the small diameter portion, while the large diameter portion provides a pressing surface for force distribution. This segmentation allows the connection to maintain strength while reducing stress concentration at the welded joint, thereby extending device lifespan.
Solution Approach 2:
The shaft has different diameters at different locations, creating local quality variations. The large diameter portion at the pressing surface area provides greater structural support and force distribution capability exactly where the repulse force and collision impact are applied, while the small diameter portion maintains a secure fit with the movable core. This localized structural optimization prevents welded part damage without compromising overall connection strength.
2Stability of the object's composition
If the shaft and movable core are rigidly connected through welding to ensure stable force transmission, then the force transmission stability is improved, but the impact from collision and spring repulsion causes welded part damage, reducing reliability
Solution Approach 1:
The stepped structure of the shaft acts as a beforehand cushioning mechanism. The large diameter portion with its pressing surface is designed in advance to absorb and distribute the repulse force from the return spring and the impact from collisions before these forces reach the connection point between the shaft and movable core. This pre-cushioning effect prevents welded part damage while maintaining stable force transmission, thereby improving connection reliability.
Solution Approach 2:
The large diameter portion of the shaft serves as an intermediary element between the return spring and the movable core. It mediates the transmission of forces by distributing the repulse force and collision impact across its larger surface area, preventing these forces from concentrating at the welded joint. This intermediary structure maintains force transmission stability while protecting the connection, thereby improving reliability.
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 enhances the endurance of the switching device by eliminating the need for welding and distributing the force more evenly, preventing part breakage during repeated motion.
Implementation Method 1
a return spring (130) placed under the shaft (310) to continuously press the shaft (310) downward
Implementation Method 2
If a current is applied to the coil (9) under the above structure, the movable core (7) moves upward
Data Source
Figure 1
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Figure 3
AI summary
Disclosed is an electromagnetic switching device. The electromagnetic switching device includes a housing, a fixed contact point inside the housing, a movable contact point positioned under the fixed contact point to repeatedly perform contact with the fixed contact point and separation from the fixed contact point, a shaft coupled with the movable contact point, a return spring to continuously press the shaft downward, and a movable core coupled with the shaft. The shaft includes a pressing surface directed downward, and the movable core is provided to make contact with an upper end of the pressing surface, so that the movable core presses the pressing surface to move up the pressing surface if the movable core and the shaft move up, and the pressing surface presses the movable core downward to push down the movable core if the movable core and the shaft move down.