Axial Flux Motor Stator Offset for Higher Torque Density
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Solution Overview
Problem
Existing axial flux machines with a double stator arrangement face challenges in maximizing torque while maintaining a compact and lightweight design, which is essential for industrial robot applications, without increasing material usage.
Innovation Solution
The axial flux machine incorporates an offset stator arrangement where the second stator poles are offset by an angle relative to the first stator poles, resulting in an asymmetrical distribution of the excitation field, which increases the excitation flux and torque without additional material, and includes a rotor with specific pole distances and configurations to optimize magnetic flux distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the double stator arrangement is used with symmetrical stator pole positioning, then the structural simplicity and ease of manufacture are improved, but the torque output and magnetic flux utilization are insufficient
Solution Approach 1:
The patent applies asymmetry by offsetting the stator poles of the first and second stators relative to each other in the circumferential direction. Specifically, the stator poles are positioned such that they do not align symmetrically, creating an asymmetric magnetic field distribution that enhances flux utilization and torque production while maintaining the double stator structure
Solution Approach 2:
The patent changes the geometric parameter of stator pole positioning by introducing an offset angle between the first and second stators. This parameter modification optimizes the magnetic coupling between stators and rotor, improving torque output without adding material or complexifying the manufacturing process
2Force
If additional material is added to increase torque, then the torque output is improved, but the compactness and lightweight design are compromised
Solution Approach 1:
The patent achieves increased torque without additional material by changing the geometric arrangement parameter - the offset positioning of stator poles. This optimizes the existing magnetic circuit's flux distribution and utilization, extracting more torque from the same material quantity
Solution Approach 2:
The asymmetric offset arrangement of stator poles improves magnetic flux balance and reduces magnetic resistance, allowing the existing materials to be used more efficiently for torque production, thereby avoiding weight increase
3Force
If the stator poles are offset by an offset angle, then the excitation flux and torque are increased, but the structural complexity and manufacturing precision requirements increase
Solution Approach 1:
The patent defines specific relationships for the offset angle parameter, such as setting it to multiples of the single rotor pole distance, which simplifies the precision requirements while maintaining the torque-enhancing asymmetric configuration
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 configuration enhances torque output by improving magnetic flux balance and reducing magnetic resistance, allowing for increased torque without material increase, suitable for compact industrial robot drives.
Implementation Method 1
a first stator (2) having a first multi-phase, more particularly three-phase, winding (5) comprising N first stator poles (5), a second stator (3) having a second multi-phase, more particularly three-phase, winding (6) comprising N second stator poles (6)... a rotor (4), which is disposed between the first stator (2) and the second stator (3) and which can be rotated relative to the first and second stators... the power source for energizing the first and second stators is designed such that the direction of the torque on the rotor (4) caused by the first stator (2) and second stator (3) is the same
Implementation Method 2
the first stator and the second stator are configured and disposed such that the second stator poles (6) of the first phase, which are provided as part of the second stator (3), are offset by an offset angle (14) in the circumferential direction in relation to the first stator poles (5) of the first phase, which are provided as part of the first stator (2)... results in an asymmetrical distribution of the excitation field, which increases the excitation flux and torque
Data Source
AI summary
The invention relates to an electric axial flux machine (1), comprising: a first stator (2) having a first multi-phase, more particularly three-phase, winding comprising N first stator poles (5), which are mutually spaced in a circumferential direction (10) of the axial flux machine (1); a second stator (3) having a second multi-phase, more particularly three-phase, winding comprising N second stator poles (6), which are mutually spaced in a circumferential direction (10) of the axial flux machine (1), a plurality of first stator poles (5) of the first winding and a plurality of second stator poles (6) of the second winding being interconnected to form a first phase (U) of the axial flux machine (1); a rotor (4), which is disposed between the first stator (2) and the second stator (3) and which can be rotated relative to the first and second stators (2, 3); a power source for energizing the first and second stators (2, 3); wherein: the first stator (2) and the second stator (3) are configured and disposed such that the second stator poles (6) of the first phase (U), which are provided as part of the second stator (3), are offset by an offset angle (14) in the circumferential direction (10) in relation to the first stator poles (5) of the first phase (U), which are provided as part of the first stator (2); the rotor (4) has a plurality of rotor poles (8); a rotor pole distance (7) is determined by the angular distance between two adjacent rotor poles (8), and the offset angle (14) is a single rotor pole distance (7) or a multiple of the single rotor pole distance (7); and the power source for energizing the first and second stators (2, 3) is designed such that the direction of the torque on the rotor (4) caused by the first and second stators (2, 3) is the same.