Rotor Resin Gate Positioning for Injection Pressure Control
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Solution Overview
Problem
Conventional rotor manufacturing processes face challenges in uniformly injecting and molding resin around magnets and core portions, leading to uneven resin distribution and reduced rigidity, especially when the gate position is eccentrically disposed, causing concentration of injection pressure and inaccurate molding.
Innovation Solution
A rotor design with a laminated core and alternately arranged magnets and core portions, featuring a resin portion with a columnar portion inside the through-hole and a gate mark positioned radially outward, allowing for efficient resin injection and distribution, reducing pressure concentration and enhancing molding accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the gate is disposed eccentrically radially outward to reliably cover the radially outside surface of the magnets with sealing resin, then the coverage of radially outside surface is improved, but the resin flow uniformity toward the through-hole and radial inner side deteriorates
Solution Approach 1:
The gate is intentionally positioned asymmetrically at an eccentric location radially outward from the center axis, rather than at the center. This asymmetric positioning allows the resin to flow preferentially toward the radially outside surface first, ensuring complete coverage of the magnet surfaces while still achieving adequate penetration to the through-hole and radial inner side.
2Manufacturing precision
If the gate is positioned radially outward to ensure magnet coverage, then the sealing resin coverage is improved, but the injection pressure concentration increases
Solution Approach 1:
The resin injection process creates localized pressure distribution where the highest pressure is concentrated at the gate location radially outward, which is exactly where it is needed to ensure complete coverage of the magnet surfaces. The pressure naturally dissipates as the resin flows toward the through-hole and radial inner side, creating an optimal pressure gradient that prioritizes magnet coverage while still achieving adequate penetration.
3Manufacturing precision
If the resin is molded with high accuracy in the through-hole and radial inside regions, then the molding precision is improved, but the resin flow uniformity requires stricter control
Solution Approach 1:
The gate is positioned radially outward in advance to establish a predetermined resin flow path that naturally guides the molten resin through the desired sequence: first covering the radially outside magnet surfaces, then flowing into the through-hole, and finally reaching the radial inner side. This preliminary positioning of the gate creates an inherent flow control mechanism that achieves accurate molding without requiring complex flow control systems.
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
The proposed design significantly reduces injection pressure concentration and ensures accurate molding of resin portions, enhancing the rigidity and effectiveness of the rotor by allowing the molten resin to spread uniformly and solidify efficiently.
Implementation Method 1
a gate through which the sealing resin is injected into a forming mold is provided
Implementation Method 2
the resin portion includes an upper resin portion which covers upper surfaces of the laminated core and the plurality of magnets, a lower resin portion which covers lower surfaces
Data Source
AI summary
A rotor includes a laminated core, a plurality of magnets, and a resin portion. The laminated core includes a plurality of outer core portions arranged in a circumferential direction. The plurality of outer core portions and the plurality of magnets are alternately arranged in the circumferential direction. In addition, the outer core portion includes a through-hole that penetrates in an axial direction. The resin portion includes a columnar portion that is disposed inside the through-hole. Accordingly, the rigidity of the resin portion is enhanced. In addition, the resin portion includes a gate mark portion. At least a portion of the gate mark portion is positioned farther radially inward than the through-hole.