Claw-teeth Rotating Machine Reducing Vibration and Noise
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Solution Overview
Problem
Brushless electric motors using reluctance torque face challenges in minimizing vibration and noise due to complex magnetic field distributions and coil ends, which hinder miniaturization.
Innovation Solution
A claw-teeth-type rotating electrical machine design featuring a cylindrical rotor with permanent magnets and a stator with annular coils and claws, generating reluctance torque with magnetic flux orthogonal to the center axis, reducing cyclic vibration and noise by equalizing magnet and reluctance torque production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a wire is wound around the stator core obtained by laminating electromagnetic steel sheets, then the coil end is inevitably formed, but the axial length of the motor increases
Solution Approach 1:
The invention extracts and eliminates the coil end portion from the motor structure by using a claw-pole type stator core where the coil is embedded within the claw poles rather than being wound around the entire stator core. This removes the protruding coil ends that increase axial length while maintaining the necessary winding function.
Solution Approach 2:
The invention changes the spatial arrangement of the coil from a conventional radial winding around the stator core to an axial embedding within the claw poles. This dimensional reconfiguration allows the coil to be integrated into the stator structure without extending axially, thus reducing the motor's axial length.
2Shape
If the magnetic field distribution at the time of no load in the air gap is not sine wave shaped, then the rotor has a complicated magnetic structure, but electromagnetic exciting force in various modes is generated causing vibration and noise
Solution Approach 1:
The invention applies local quality by configuring the claw poles with specific tooth widths and spacing to create localized magnetic field characteristics. The claw poles are designed with optimized dimensions and arrangements that shape the magnetic field distribution to be more sinusoidal, reducing harmonic content and the resulting electromagnetic exciting forces that cause vibration and noise.
Solution Approach 2:
The invention changes key parameters of the magnetic circuit including the number of claw poles, their tooth widths, and spacing arrangements to optimize the magnetic field distribution. By adjusting these parameters, the magnetic field waveform is improved to reduce harmonics and minimize vibration and noise while maintaining the desired magnetic structure.
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 design effectively reduces vibration and noise while utilizing reluctance torque, enabling motor miniaturization and improved high-speed rotation output without coil ends, thus enhancing motor efficiency and size reduction.
Implementation Method 1
magnet flux in a direction orthogonal to a center axis direction of the magnetic pole of the permanent magnet
Implementation Method 2
A brushless electric motor having such functions is disclosed, including: a stator obtained by winding a distributed coil around a stator core formed by laminating electromagnetic steel sheets; and a rotor having a permanent magnet and a high-permeability magnetic member (auxiliary salient pole)
Implementation Method 3
a coil for magnetizing the stator core. The coil is a annular coil obtained by winding a wire annularly
Data Source
AI summary
To realize reduction in vibration and noise while utilizing reluctance torque, a rotating electrical machine includes: a rotor having permanent magnets disposed in a cylindrical surface coaxial with a rotary shaft; and a stator having an annular stator core disposed coaxially with the rotary shaft, and a annular coil for magnetizing the stator core. The stator core has an annular part covering the annular coil, claws disposed at equal intervals in an inner radius surface of the annular part and extending axially, and magnetic gaps formed between neighboring claws. The number of claws is equal to the number of permanent magnets, and magnet flux in a direction orthogonal to a center axis of the magnetic pole of the permanent magnet at right angles in electric angle is larger than magnetic flux in the center axis direction generated between neighboring permanent magnets. Metal interpoles are provided between neighboring permanent magnets.