Insert-Molded Resin Gear Assembly With Anti-Rotation Plate Positioning
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Solution Overview
Problem
The challenge is to prevent rotation of a metal plate during insert molding with a resin gear, which affects the processing accuracy of the gear teeth, while ensuring sufficient fastening strength between the metal shaft and the plate.
Innovation Solution
A rotating component design featuring a metal shaft with a circular cross-section and a metal plate having a circular fitting hole and a positioning recess, where the plate is fixed using the recess to prevent rotation during molding, and the shaft is crimped to the plate for enhanced fastening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the metal plate is fixed to the shaft using a simple circular fitting hole, then the fastening strength is sufficient, but the plate rotates during insert molding affecting gear tooth precision
Solution Approach 1:
The patent introduces asymmetric positioning recesses and corresponding positioning protrusions on the shaft. These asymmetric features prevent rotational movement of the plate relative to the shaft by creating a unique angular orientation, thereby ensuring the plate maintains a fixed position during insert molding to achieve precise gear tooth processing.
2Manufacturing precision
If positioning recesses are added to prevent plate rotation, then manufacturing precision improves, but the device complexity increases
Solution Approach 1:
The positioning recesses are pre-formed on the metal plate before the insert molding process, and the positioning protrusions are pre-formed on the shaft. This preliminary positioning action ensures that when the plate is mounted on the shaft, it is automatically positioned in the correct angular orientation before resin injection, preventing rotation during molding without requiring complex active control mechanisms.
3Device complexity
If the plate structure is simplified without positioning features, then device complexity is reduced, but the plate rotates during molding reducing manufacturing precision
Solution Approach 1:
The patent introduces asymmetric positioning recesses and corresponding positioning protrusions on the shaft. These asymmetric features prevent rotational movement of the plate relative to the shaft by creating a unique angular orientation, thereby ensuring the plate maintains a fixed position during insert molding to achieve precise gear tooth processing.
4Ease of manufacture
If the shaft and plate are connected without positioning features, then ease of manufacture is improved, but reliability of the connection is reduced due to potential rotation
Solution Approach 1:
The patent introduces asymmetric positioning recesses and corresponding positioning protrusions on the shaft. These asymmetric features prevent rotational movement of the plate relative to the shaft by creating a unique angular orientation, thereby ensuring the plate maintains a fixed position during insert molding to achieve precise gear tooth processing.
Solution Approach 2:
The positioning recesses are pre-formed on the metal plate before the insert molding process, and the positioning protrusions are pre-formed on the shaft. This preliminary positioning action ensures that when the plate is mounted on the shaft, it is automatically positioned in the correct angular orientation before resin injection, preventing rotation during molding without requiring complex active control mechanisms.
Data Source
AI summary
A rotating component includes a metal plate fixed to an end portion of the metal shaft, and a resin valve gear integrally formed with the plate by insert molding. The plate is formed with a circular fitting hole that fits with the end portion of the shaft, and a positioning recess that is recessed from one side to the other side of the plate.