Brushless Outrunner Chainsaw for High Power in a Compact Body
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Solution Overview
Problem
Chainsaws with high output power are bulky and heavy, making them difficult to handle and unsuitable for prolonged use due to their size and weight.
Innovation Solution
A chainsaw design with a power-to-mass ratio of 0.5 kW/kg to 2.0 kW/kg, incorporating a brushless outrunner motor, a brake device with mechanical and electronic braking, and a lubrication system, optimized for reduced volume and weight while maintaining high power output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the chainsaw is designed with high output power, then the cutting efficiency is improved, but the volume and weight of the chainsaw increase
Solution Approach 1:
The patent applies parameter changes by optimizing the power-to-mass ratio to a specific range (0.5-2.0 kW/kg) and controlling the center of gravity position relative to the body portion. This resolves the contradiction by finding optimal parameter values that provide high cutting power while keeping the chainsaw weight manageable for user comfort.
2Power
If the chainsaw is designed with high output power, then the cutting efficiency is improved, but the volume of the chainsaw increases
Solution Approach 1:
The patent resolves this contradiction by optimizing the power-to-mass ratio parameter and controlling the spatial distribution of components. By positioning the center of gravity within the body portion's projection and optimizing the accommodating space utilization, the design achieves high power output within a compact volume that remains easy for users to hold.
3Ease of operation
If the chainsaw weight is reduced, then the ease of operation is improved, but the output power decreases
Solution Approach 1:
The patent applies parameter changes by establishing an optimal power-to-mass ratio range (0.5-2.0 kW/kg) that balances weight reduction with power maintenance. This ensures the chainsaw remains easy to hold and operate while preserving sufficient cutting power for effective performance.
Solution Approach 2:
The patent replaces traditional mechanical braking systems with an electronic brake device that uses electromagnetic braking. This substitution reduces mechanical component weight and complexity while providing effective braking control, thereby improving ease of operation without sacrificing power transmission efficiency.
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 achieves a balance between power and portability, allowing for efficient cutting with reduced weight and size, enhancing user comfort and usability.
Implementation Method 1
a motor configured to drive the chain
Implementation Method 2
a brake device configured to brake the motor
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Provided is a chainsaw. The chainsaw includes a tool body (1) and a power supply device (2), where the power supply device (2) is configured to provide a power source for the tool body (1). The tool body (1) includes: a housing (13); a chain (12) configured to perform a cutting function; a guide plate (11) for supporting and guiding the chain (12); a drive device (14), where the drive device (14) is at least partially disposed in an accommodating space formed by the housing (13) and includes a motor (141) configured to drive the chain (12); and a brake device (15) configured to brake the drive device (14). The tool body (1) includes a main machine (30). The main machine (30) includes at least the housing (13), the drive device (14), and the brake device (15). The motor is an outrunner. The power-to-mass density of the main machine (30) is greater than or equal to 0.5 kW/kg and less than or equal to 2.0 kW/kg. The mass of the main machine (30) is the mass of the tool body (1) with the chain (12) and the guide plate (11) removed.