Rotating Electrical Machine Rotor Core Plate Compression
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Solution Overview
Problem
Rotating electrical machines with IPM rotors face stress concentration issues due to rivets or bolts, leading to potential damage or deformation under mechanical impact or vibration, especially in vehicles.
Innovation Solution
A rotating electrical machine design featuring a magnetic core made of stacked annular core plates with a deformable annular end plate, which distributes mechanical stress and absorbs impact through air gaps, minimizing damage by using bar-shaped fastening members with flanges that engage the end plate to compress the core plates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If rivets or bolts are used to compress the stack of magnetic steel plates, then the core plates are tightly compressed, but stress concentrates on the contact points between the fastening members and the core plates, leading to potential breakage or deformation
Solution Approach 1:
The patent introduces an intermediate element (the deformable end plate with wave structure) between the fastening members and the core plates. This intermediary distributes the compressive force across a larger area and absorbs mechanical impacts, preventing stress concentration on the thin core plates while maintaining tight compression.
Solution Approach 2:
The end plate is designed with a wave structure that changes its physical state from rigid to elastically deformable. This parameter change allows the plate to absorb impact energy through elastic deformation, reducing stress transmission to the core plates during mechanical shocks or vibrations.
2Weight of moving object
If the core plates are made thin to reduce weight and size, then the machine becomes more compact, but the core plates become more susceptible to breakage or bending under mechanical impact or vibration
Solution Approach 1:
The wave-shaped end plate serves as a pre-designed cushioning element that is built into the structure before assembly. The wave structure creates air gaps that can be compressed during impact, absorbing mechanical energy before it reaches the thin core plates, thereby protecting them from breakage or bending.
Solution Approach 2:
The end plate is designed as a flexible, elastically deformable component with a wave structure. This flexible structure can deform under impact loads and return to its original shape, providing continuous protection to the thin core plates against mechanical shocks and vibrations during operation.
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 solution effectively reduces stress concentration on the core plates, preventing breakage or bending and enhancing the machine's durability under mechanical stress, such as vibration in vehicle applications.
Implementation Method 1
The end plate has a wave which is deformable in the axial direction... The end plate is designed in the form of a wave to be elastically deformable in the lengthwise direction
Data Source
AI summary
A rotating electrical machine is equipped with a rotor and a stator. The rotor includes a magnet unit and a rotor core retaining the magnet unit. The rotor core is made of a stack of annular core plates and an annular end plate mounted on an end of the stack of the core plates. The end plate has a deformable wave shape. The stack of the core plates and the end plate has formed therein through-holes extending through a length thereof. Bar-shaped fastening members, such as rivets, which have flanges on ends thereof are inserted into the through-holes with the flanges pressing the end plate to elastically deform the wave shape of the end plate, thereby tightly gripping the stack of the core plates in the lengthwise direction. This minimizes concentration of stress on the core plates to eliminate a risk of damage or breakage of the rotor.