Resin Worm Injection Molding Pin Support
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
When manufacturing a worm using injection molding with a resin material, the end of the mold pin supporting the insertion hole for the shaft is not adequately supported in the radial direction, leading to potential inclination during molding, which can result in vibration or unusual noise when the worm is meshed with a worm wheel or helical gear.
Innovation Solution
A worm with a gear portion and a top portion featuring multiple recesses that communicate with a cavity, formed on the outer peripheral side of the gear portion, is designed to prevent pin bending during injection molding, ensuring accurate alignment and reducing noise and vibration by supporting the pin with protruding portions from a second movable mold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If injection molding is performed with a single-end supported pin, then manufacturing simplicity is maintained, but molding precision deteriorates due to pin inclination
Solution Approach 1:
The pin support structure transitions from one-dimensional (single-end support) to three-dimensional support by adding protruding portions that extend from the movable mold in the radial direction, providing multi-point support at the pin tip end to prevent inclination during injection molding
Solution Approach 2:
Protruding portions are introduced as intermediary structures that mediate between the movable mold and the pin, providing mechanical support to the pin tip end during molding to maintain pin straightness and insertion hole alignment accuracy
2Manufacturing precision
If pin support structure is added to prevent inclination, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The pin support function is merged with the movable mold structure by integrating protruding portions directly into the movable mold body, eliminating the need for separate support devices and reducing overall system complexity while maintaining manufacturing precision
3Ease of manufacture
If pin inclination occurs during molding, then manufacturing simplicity is maintained, but product reliability deteriorates due to vibration and noise
Solution Approach 1:
The protruding portions provide preliminary support to the pin tip end before injection molding begins, preventing pin inclination during the molding process, thereby ensuring insertion hole accuracy and preventing subsequent vibration and noise issues during worm meshing operations
Data Source
AI summary
A worm (40) according to an embodiment is a worm made of resin and formed by injection molding. The worm includes a gear portion (40a), a cavity (40c) having an axis being a longitudinal axis (40d) of the worm being formed at the gear portion, and a top portion (40b) formed at a first end portion of the gear portion in a direction of the longitudinal axis. A plurality of recesses (40e) including a hole portion communicating with the cavity are formed at the top portion in a radial direction, and are located on an outer peripheral portion side of the gear portion with respect to the cavity.