Compact Permanent Magnet Motor Power Density Optimization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional portable power tools face challenges in achieving high power density due to the need for compact motor designs that maximize force while minimizing size.
Innovation Solution
A permanent magnet motor with a stator and rotor configuration, utilizing high energy magnets and a ferrite ring for electromagnetic interference suppression, where the ratio of magnet thickness to rotor diameter is optimized to enhance power output within a compact form factor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the motor size is reduced to keep portable power tools compact, then the portability and compactness are improved, but the output power and force decrease
Solution Approach 1:
The patent applies parameter changes by optimizing the ratio of magnet thickness to rotor diameter within the range of 1:7 to 1:50. This specific parameter optimization allows the motor to achieve high power density in a compact size, resolving the contradiction between reduced motor volume and maintained output power. The controlled parameter range ensures maximum force output while keeping the motor small enough for portable tools.
2Power
If the magnet thickness is reduced to increase rotor diameter, then the power density is improved, but the magnetic field strength may decrease
Solution Approach 1:
The patent resolves this contradiction by precisely controlling the magnet thickness to rotor diameter ratio within 1:7 to 1:50. This parameter optimization ensures that even with reduced magnet thickness, the magnetic field strength remains sufficient to generate high power density. The specific ratio range balances magnetic field strength and power density, allowing the motor to achieve maximum efficiency.
3Power
If the rotor diameter is increased to enhance power output, then the power density is improved, but the motor size increases
Solution Approach 1:
The patent applies parameter changes by optimizing the magnet thickness to rotor diameter ratio within 1:7 to 1:50, which allows increased rotor diameter for higher power output while maintaining compact overall motor dimensions. This controlled parameter relationship ensures that the motor achieves high power density without excessive size increase, resolving the contradiction between power output and motor size.
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 increases power output and power density by reducing magnet thickness and increasing rotor diameter, making the motor suitable for compact power tools like drills, hammers, and saws.
Implementation Method 1
a permanent magnet motor comprising: a stator having a housing and a plurality of magnets installed at an inner surface of the housing; and a rotor installed in the stator
Data Source
AI summary
An electric motor includes a stator and a rotor rotatably installed in the stator. The stator has a housing and a plurality of permanent magnets. The outer diameter of the housing is less than 40 mm and the ratio of the maximum thickness of the magnets in the radial direction of the rotor to the diameter of the rotor is in the range of 1:7 to 1:50.