Dual-Gate Casting Mold for Rotor Porosity Reduction
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Solution Overview
Problem
The existing methods for producing rotors with metal cores, such as electric motors, result in high porosity in the conductor cages due to the casting process, which reduces their physical and electrical properties, leading to inefficiencies and mechanical instability.
Innovation Solution
A method using a casting machine with a dual-gate casting mold where molten metal is introduced through two gates, one for each short-circuit ring, allowing the melt fronts to meet within the mold, reducing flow speed and turbulence, and enabling a more controlled filling process to minimize porosity and enhance electrical conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single-gate casting process is used to fill the mold, then the filling speed is high and productivity is improved, but the flow speed and turbulence increase leading to high porosity and reduced manufacturing precision
Solution Approach 1:
The casting process is segmented into two separate filling operations using two gates positioned at opposite ends of the rotor. Each gate fills a portion of the mold cavity independently, allowing the melt front to travel shorter distances at reduced velocities. This segmentation of the filling path directly reduces turbulence and porosity while maintaining overall productivity through parallel filling action.
2Productivity
If the metal flows quickly through the grooves to complete casting rapidly, then productivity is improved, but the rapid cooling causes increased porosity and reduced manufacturing precision
Solution Approach 1:
The casting mold is divided into two filling zones with gates positioned at opposite ends of the rotor core. Each gate independently fills its respective half of the mold cavity, effectively halving the flow path length through the grooves. This allows the metal to fill the mold at a controlled, slower velocity that prevents excessive cooling and porosity formation, while the dual-gate configuration maintains overall casting efficiency.
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 approach significantly reduces porosity, improving the mechanical and electrical properties of the rotor, allowing for higher efficiency and stability, including increased electrical conductivity and reduced oxide formation at grain boundaries.
Implementation Method 1
a first melt front of the metal of the first gate meets a second melt front of the metal of the second gate within the mold in the second shorting ring
Data Source
Figure 1~3
Figure 4~5
AI summary
The invention relates to a method and a mold for manufacturing a rotor for an electric machine, in particular a three-phase motor, wherein the rotor (18) is formed from a metal core, at least a first and a second short-circuit ring (36, 37), and lamellar conductors (25) connecting the short-circuit rings, wherein the method is carried out with a casting machine and a mold (29), wherein the metal core is arranged in the mold and a metal is applied to the metal core in the mold, wherein the metal is melted and introduced into the mold, wherein the metal is copper, aluminum, silver, or an alloy of one of these metals, wherein the metal is introduced into the mold at a first gate (34) of the mold at the first short-circuit ring (36), and at a second gate (35) of the mold at the second short-circuit ring (37).