Hand-Held Power Tool Weight-to-Power Ratio Optimization
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Solution Overview
Problem
Hand-held power tools with electronically commutated electric motors face challenges in ergonomic design due to component geometry and mass, leading to unfavorable handling characteristics and fatigue for operators.
Innovation Solution
Optimizing the ratio of tool weight to nominal power, electronically commutated electric motor weight to nominal power, and electronics system volume to motor volume, along with efficient cooling and power distribution, to achieve a balanced and efficient hand-held power tool design that minimizes fatigue and maximizes performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the power output of the hand-held power tool is increased, then the performance capability is improved, but the weight increases leading to unfavorable ergonomics and operator fatigue
Solution Approach 1:
The patent applies parameter changes by optimizing the ratio relationship between motor weight and power output. Specifically, it establishes that the ratio of motor weight to power output should fall within 0.3 to 0.6 kg/kW, and the ratio of total tool weight to power output should be 0.5 to 0.8 kg/kW. These optimized parameter ranges enable the tool to achieve high power output while maintaining acceptable weight characteristics for ergonomic handling.
2Volume of moving object
If the size of the electronically commutated electric motor is reduced to improve ergonomics, then the handling characteristics are improved, but the performance capability may be compromised
Solution Approach 1:
The patent resolves this contradiction through parameter optimization by defining specific ratio ranges. The motor weight to power output ratio is optimized to 0.3-0.6 kg/kW, and the total tool weight to power output ratio is optimized to 0.5-0.8 kg/kW. These parameter specifications ensure that the motor achieves high power density, delivering maximum performance within minimal volume and weight constraints, thus improving both ergonomics and performance capability simultaneously.
3Power
If the ratio of electronics system volume to motor volume is optimized, then the performance capability and power delivery are improved, but the structural space requirements increase
Solution Approach 1:
The patent applies parameter changes by establishing an optimized volume ratio between the electronics system and the motor. The volume ratio of the electronics system to the motor is specified to be between 0.3 and 0.7. This optimized ratio ensures that the electronics system has sufficient space for effective heat dissipation and power delivery while minimizing the overall structural space occupied, thus balancing power delivery efficiency with compact design requirements.
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 optimized design results in a hand-held power tool with improved ergonomics, reduced fatigue, high performance capability, and efficient power usage, ensuring comfortable operation and effective power delivery without overheating.
Implementation Method 1
an drive unit (12) having an electronically commutated electric motor (22)
Data Source
AI summary
A hand-held power tool, in particular an angle grinder, having a drive unit, has an electronically commutated electric motor and has an electronics system which is integrated in an appliance housing. The ratio of a weight of the hand-held power tool MHWZM to a nominal power PN is selected in such a way that, in a power range of from 0 to 1200 W, the ratio of the weight of the hand-held power tool MHWXM to the nominal power PN is at most 0.75 g/W*PN+1200 g, and, at a value of the nominal power of greater than 1200 W, the ratio of the weight of the hand-held power tool to the nominal power is at most 2.2*PN−540 g.