Compressor Motor Rotor Core Axial Length Optimization
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Solution Overview
Problem
Conventional compressor motors face a trade-off where shortening the axial length to reduce size and weight leads to decreased motor efficiency due to increased magnetic flux leakage and torque loss, and existing methods to improve efficiency, such as enhancing coil space factor, cannot prevent torque decrease.
Innovation Solution
A compressor motor design where the axial length of the rotor core (L) is maintained such that L/D > 0.2 and t > (1×K×N) / (L^1.5 × D × P), with K = 100000, N depending on compressor output, to minimize magnetic flux leakage and maintain torque, thereby allowing for a small-sized, lightweight, and low-priced motor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the axial length of the rotor core is shortened to reduce motor size and weight, then the motor becomes more compact and lighter, but magnetic flux leakage increases and torque decreases
Solution Approach 1:
The patent applies parameter changes by establishing specific mathematical relationships between the axial length L, radial length D, and magnet thickness t of the rotor. The conditions L/D ≥ 0.2 and t ≥ (1×K×N)/(L^1.5×D×P) define optimal parameter ranges that balance motor compactness with sufficient torque output, resolving the contradiction between size reduction and torque maintenance
Solution Approach 2:
The patent addresses the axial length limitation by optimizing the radial dimension (magnet thickness t) and the L/D ratio. This dimensional shift allows the motor to maintain torque performance through increased radial magnet thickness while keeping the axial length short, effectively trading axial space for radial space
2Weight of moving object
If the axial length of the rotor core is shortened, then the motor weight is reduced, but magnetic flux leakage from axial end faces increases
Solution Approach 1:
The patent uses parameter changes by defining the L/D ratio constraint (≥ 0.2) and the magnet thickness formula that accounts for axial length. These parameter relationships ensure that even with shortened axial length, the magnet thickness is sufficient to maintain magnetic flux density and reduce leakage, thereby preventing energy loss while achieving weight reduction
3Use of energy by moving object
If the coil space factor is improved to increase motor efficiency, then motor efficiency improves, but torque decreases and coil winding quantity increases
Solution Approach 1:
The patent applies parameter changes by establishing the magnet thickness formula t ≥ (1×K×N)/(L^1.5×D×P) which directly relates magnet dimensions to motor output requirements. This approach maintains torque by optimizing magnetic field strength at the source (rotor magnets) rather than increasing coil winding quantity, thereby avoiding the torque decrease associated with improved coil space factor methods
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 design prevents efficiency decreases due to magnetic flux leakage, enabling a small-sized, lightweight, and low-priced compressor motor with maintained torque performance.
Implementation Method 1
a plurality of magnets arrayed on the rotor core in its circumferential direction at center angles of equal intervals... a coil wound around the stator core
Implementation Method 2
magnetic flux leakage from both axial end faces of the rotor increases
Data Source
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AI summary
A rotor 6 includes a rotor core 610, and a plurality of magnets 620 arrayed on the rotor core 610 in its circumferential direction at center angles of equal intervals. Given an axial length L of the rotor core 610, a radial length D of the rotor core 610, and a thickness t of the magnets 620, the following relationships are satisfied: L/D < 0.7, and t > (1×K×)/(L1.5×D×P) (wherein P is the number of poles, K is 100000, and N is a factor that depends on the output of the compressor). Thus, while torque decreases due to large reduction in rotor layering thickness is suppressed, a small-size, lightweight and low-priced compressor motor is provided.