Guided Wedge Element for Electric Rotor Insulation
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Solution Overview
Problem
High-speed rotation in automotive rotary electric machines causes centrifugal forces that weaken the electrical insulation of field coils in wound rotors, potentially leading to short-circuits or mechanical failure, and existing solutions like resin impregnation are not space-efficient or easy to manufacture.
Innovation Solution
The use of wedge elements with axial extensions and complementary grooves in the rotor teeth to secure and insulate the field coil, allowing for efficient sealing and potting material injection without occupying much space, while being made of insulation material for electrical insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional solutions like resin impregnation are used to fix the field coil, then the field coil is mechanically held and insulated, but the manufacturing process becomes complex and space between adjacent teeth is occupied
Solution Approach 1:
The invention divides the fixation function into separate wedge elements positioned in slots between adjacent teeth, rather than using a continuous resin impregnation process. Each wedge element independently secures the field coil in its respective slot, simplifying the manufacturing process while maintaining reliable mechanical holding and insulation.
Solution Approach 2:
The invention extracts the fixation and insulation function from the resin impregnation process and implements it through dedicated wedge elements. These wedge elements are inserted into slots between teeth, separating the fixation mechanism from the field coil itself and enabling easier manufacturing without complex impregnation procedures.
2Reliability
If wedge elements are added to secure the field coil, then mechanical holding is improved, but space between adjacent teeth is reduced
Solution Approach 1:
The wedge elements are positioned in the axial dimension within slots between adjacent teeth, rather than occupying radial or tangential space. This axial placement allows the wedge elements to provide mechanical holding without significantly reducing the space available for the field coil windings in the critical radial dimension.
Solution Approach 2:
The wedge elements are specifically positioned only where needed - in the slots between adjacent teeth - providing localized mechanical holding and insulation exactly where the field coil requires support. This localized approach minimizes the overall space occupied while maximizing the mechanical holding effectiveness at critical points.
3Power
If the rotor is designed for high-speed rotation, then power output is improved, but centrifugal forces weaken the electrical insulation of the field coil
Solution Approach 1:
The wedge elements are pre-positioned in the slots between teeth before the field coil is installed, creating a preliminary protective structure that resists the centrifugal forces that will act on the field coil during high-speed rotation. This preliminary anti-action prevents the field coil from moving or becoming loose under centrifugal stress.
Solution Approach 2:
The wedge elements appear to be made of insulating material that provides both mechanical support and electrical insulation. This composite approach combines structural reinforcement with electrical insulation in a single component, addressing both the mechanical holding requirement and the electrical insulation requirement simultaneously.
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention concerns a rotor comprising a rotor shaft, a rotor body formed of a stack of laminations having a plurality of teeth (21) projecting radially, a field coil (3) wound around each tooth of the plurality of teeth (21), a plurality of wedge elements (110) each wedge element (110) of the plurality of wedge elements (110) being configured to be slid into corresponding grooves (210) provided in the bulk of each of the respective two adjacent teeth.