Rotor Injection Molding Sealing via Disk Delimitation
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Solution Overview
Problem
Conventional methods for impregnating rotors of electrical machines, particularly in motor vehicles, require complex and costly molds and dies to prevent plastic leakage, limiting cost-effectiveness and versatility in producing different variants.
Innovation Solution
The method involves using a disk to delimit a partial region of the rotor, allowing for injection molding with a simple and cost-effective die configuration, where a sealing element, heated by the injected plastic, prevents leakage and ensures a virtually closed contour, enabling efficient impregnation with thermosetting plastics at high pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional methods are used to prevent plastic leakage during injection molding, then sealing reliability is improved, but device complexity and manufacturing cost increase due to complex molds and dies
Solution Approach 1:
The rotor components themselves (disk, laminated core, sealing element) perform the sealing function without requiring external complex sealing systems. The sealing element is heated by the injected plastic itself, creating a self-contained sealing mechanism that eliminates the need for complex external molds and dies
Solution Approach 2:
The sealing element changes its physical properties through heating by the injected plastic, transitioning to a state where it effectively seals the partial region. This parameter change (temperature-induced sealing) provides reliable sealing without complex mechanical sealing structures
2Manufacturing precision
If complex molds and dies are used to prevent plastic leakage, then manufacturing precision is improved, but manufacturing cost increases
Solution Approach 1:
The rotor structure performs the molding containment function itself through its components (disk delimiting the partial region, sealing element preventing leakage). This self-contained approach eliminates the need for expensive specialized molds and dies while maintaining precise injection molding
Solution Approach 2:
The sealing function is extracted from the mold/die system and integrated into the rotor structure itself. The sealing element becomes part of the rotor, eliminating the need for complex external sealing mechanisms in the molding equipment
3Adaptability or versatility
If the same die is used for different rotor variants, then adaptability is improved, but manufacturing precision may worsen due to lack of specialized tooling
Solution Approach 1:
A single simple die structure can produce different rotor variants by utilizing the rotor's own components (disk, laminated core, sealing element) to define the specific geometry and sealing. The die serves multiple functions: containing the plastic, heating the sealing element, and defining the partial region, while the rotor components provide variant-specific precision
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 allows for cost-effective production of rotors with high strength and versatility, reducing the need for complex sealing measures and enabling the production of various variants using the same die, while ensuring the rotor can withstand high rotational speeds.
Implementation Method 1
a sealing element, heated by the injected plastic, prevents leakage
Data Source
AI summary
A method produces a rotor having at least one laminated core for an electrical machine, in which method at least one partial region of the rotor is provided with a plastic by injection molding. The method provides at least one disk following the laminated core in the axial direction of the rotor, by which disk the partial region is at least to a large extent delimited in the axial direction of the rotor; and by the injection molding, injects the plastic into the partial region via at least one through-opening in the disk leading into the partial region.