Rocking Armature Assembly With Roughened Bonding Interface
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Solution Overview
Problem
The bonding force between the armature and the plastic part in existing electromagnetic relays is weakened due to differing shrinkage rates of iron and plastic, leading to detachment issues.
Innovation Solution
A seesaw-type armature assembly with a rough structure on the armature surface and plastic swing arms, along with extension tabs embedded in the plastic part, enhances bonding force by increasing contact area and preventing detachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the armature and plastic part are bonded through injection molding, then the assembly is formed as an integral structure, but the bonding force decreases after high-temperature baking due to different shrinkage rates
Solution Approach 1:
The invention applies a rough structure specifically at the bonding surface of the armature where it contacts the plastic part, while keeping other surfaces smooth. This localized surface treatment increases the contact area and bonding force precisely where needed, without affecting the overall integral structure or magnetic conduction performance.
Solution Approach 2:
The rough structure is pre-formed on the armature surface before injection molding. This preliminary surface preparation ensures that when the plastic part is molded onto the armature, the bonding interface already has enhanced mechanical interlocking capability, which maintains bonding strength even after high-temperature baking.
2Strength
If a rough structure is added on the armature surface to increase contact area, then bonding force is enhanced, but device complexity increases
Solution Approach 1:
The rough structure creates a porous or textured surface morphology on the armature at the bonding interface. This porous structure increases the effective contact area and mechanical interlocking with the plastic part, enhancing bonding force without requiring additional components or complex assembly steps.
3Strength
If extension tabs are embedded in the plastic swing arm, then bonding strength at the root is increased and detachment is prevented, but manufacturing complexity increases
Solution Approach 1:
The extension tabs are nested within the plastic swing arm during injection molding. The tabs protrude from the armature and are embedded into corresponding cavities in the swing arm, creating a nested structure that enhances bonding strength and prevents detachment while being formed in a single molding operation.
Data Source
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AI summary
A rocking armature assembly, comprising a first armature and a plastic part. The first armature comprises a fist end portion, a middle portion and a second end portion, and the plastic covers the middle portion of the first armature, the middle portion of the fisrt armature has a first surface and a second surface opposite each other, and a rough structure is provided on one of the surfaces, such that the contact area of the first armature and the plastic part is increased, thereby enhancing the adhesion between the first armature and the plastic part, the plastic pat is provided with a plastic swing extends through an end portion of the plastic part in a direction away from the middle portion of the first armature, and inclines in the thickness direction of the first armature.