Rotary Electric Machine with Stacked Rotor Core
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Solution Overview
Problem
Conventional rotary electric machines face design constraints and high 'iron loss' due to the mismatched diameters of field coils, rotors, and stators, limiting design freedom and output performance, and experiencing significant heat generation and eddy currents from ferrous materials.
Innovation Solution
A brushless winding field type rotary electric machine with a stator and field coil in a stationary case, a rotor around the outer periphery, and a rotor core made of stacked electromagnetic steel sheets, allowing for improved design flexibility and reduced 'iron loss' by optimizing magnetic flux and heat management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the field coil, rotor and stator with different diameters are disposed coaxially with the rotation shaft, then the magnetic flux can be generated, but the degree of freedom in design is limited and the output performance is constrained due to narrow space restrictions
Solution Approach 1:
The invention transitions from a traditional coaxial arrangement (single radial dimension) to a non-coaxial configuration where the field coil is radially displaced from the rotation shaft. This dimensional change allows the field coil, rotor, and stator to be arranged in a staggered configuration rather than concentric circles, thereby increasing design freedom and output performance without being constrained by narrow radial space.
2Strength
If the rotor is formed of a massive ferrous material, then the structural strength is sufficient, but eddy currents are generated and heat generation by electric resistance occurs, resulting in large iron loss
Solution Approach 1:
The invention segments the rotor structure by introducing radial slots that divide the massive ferrous rotor material into separate radial sections. These slots interrupt the continuous path for eddy currents, thereby reducing eddy current losses and heat generation while maintaining sufficient structural strength through the segmented configuration.
Solution Approach 2:
The invention applies different properties to different parts of the rotor: the bulk material remains ferrous for structural strength, while radial slots are introduced in specific locations to interrupt eddy current paths. This local modification reduces iron loss without compromising overall rotor strength.
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
Enhances design freedom and output performance while reducing 'iron loss' and improving energy efficiency by allowing the rotor and stator to be positioned on different diameters and utilizing electromagnetic steel sheets for the rotor core.
Implementation Method 1
an AC coil for generating a rotating magnetic field by an AC current
Implementation Method 2
a field coil excited by a DC current
Implementation Method 3
the rotor core is constituted by stacking electromagnetic steel sheets in the axial direction of the rotation shaft, and the stacked electromagnetic steel sheets are electrically insulated mutually although they allow a magnetic flux to pass through
Data Source
AI summary
A brushless winding field type rotary electric machine equipped with a stator, a field core having a field coil, and a rotor. The field coil is in parallel with the rotor in the rotary member rotation shaft axial direction. The rotor has first and second magnetic poles respectively having first and second annular sections and first and second pawl sections, and an annular-shaped rotor core having first and second fitting sections into which the first and second pawl sections are respectively fitted, the first and second fitting sections being provided alternately along the circumferential direction, and the rotor core having through hollow sections each disposed between the first and second fitting sections. The first magnetic pole and the second magnetic pole are fixed to the rotor core without making contact with each other and the rotor core is constituted by stacking electromagnetic steel sheets in the axial direction.