Brushless Power Tool Speed Control Without Mechanical Gears
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Solution Overview
Problem
Existing power tools with mechanical transmission struggle to provide optimal combinations of rotational motor speed and torque for drill bits with different diameters, leading to compromised drilling speed and service life, while being bulky and unwieldy.
Innovation Solution
A power tool equipped with a brushless electric motor and electronic rotational speed graduation, allowing a rotational speed spread of greater than 2 without mechanical transmission, maintaining constant circumferential speed and enabling optimal operation of drill bits with various diameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a mechanical transmission with 2 or 3 gears is used to achieve rotational speed spread, then the power tool can provide multiple rotational speed levels, but the device becomes bulky and unwieldy
Solution Approach 1:
The patent replaces the mechanical transmission system with an electronic control system that regulates motor speed electronically. The brushless motor is controlled through electronic commutation and speed regulation circuits, eliminating the need for mechanical gears and transmission components while achieving the same rotational speed spread functionality.
Solution Approach 2:
The patent changes the control parameter from mechanical gear ratios to electronic speed regulation parameters. By controlling the commutation timing and pulse width modulation (PWM) duty cycle of the brushless motor, the system can continuously adjust rotational speed across a wide range without discrete gear steps, achieving rotational speed spread through parameter variation rather than mechanical transmission.
2Adaptability or versatility
If a mechanical transmission is used to provide rotational speed graduations, then the power tool can operate at different speeds, but the handling becomes more difficult
Solution Approach 1:
The patent replaces the mechanical transmission system with an electronic control system that regulates motor speed electronically. The brushless motor is controlled through electronic commutation and speed regulation circuits, eliminating the need for mechanical gears and transmission components while achieving the same rotational speed spread functionality.
Solution Approach 2:
The patent implements dynamic electronic speed control that allows continuous adjustment of rotational speed based on real-time operational requirements. The electronic control system can rapidly and smoothly transition between different speed levels without the inertia and discrete steps inherent in mechanical gear systems, improving responsiveness and ease of operation.
3Volume of moving object
If compromises are accepted in terms of drilling speed to keep power tools compact, then the device size is reduced, but productivity decreases
Solution Approach 1:
The patent replaces the mechanical transmission system with an electronic control system that regulates motor speed electronically. The brushless motor is controlled through electronic commutation and speed regulation circuits, eliminating the need for mechanical gears and transmission components while achieving the same rotational speed spread functionality.
Solution Approach 2:
The patent changes the control parameter from mechanical gear ratios to electronic speed regulation parameters. By controlling the commutation timing and pulse width modulation (PWM) duty cycle of the brushless motor, the system can continuously adjust rotational speed across a wide range without discrete gear steps, achieving rotational speed spread through parameter variation rather than mechanical transmission.
4Volume of moving object
If compromises are accepted in terms of service life to keep power tools compact, then the device size is reduced, but reliability decreases
Solution Approach 1:
The patent replaces the mechanical transmission system with an electronic control system that regulates motor speed electronically. The brushless motor is controlled through electronic commutation and speed regulation circuits, eliminating the need for mechanical gears and transmission components while achieving the same rotational speed spread functionality.
Solution Approach 2:
The patent extracts and removes the mechanical transmission system entirely from the power tool design. By eliminating the mechanical gears, belts, and transmission components, the system reduces mechanical wear, friction, and potential failure points, thereby improving service life and reliability while maintaining a compact form factor through electronic control.
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 solution enables improved drilling speed and extended service life, while making the power tool more compact, lightweight, and easier to handle, by providing suitable combinations of rotational speed and torque for different drill bits.
Implementation Method 1
a motor, the motor being a brushless electric motor
Data Source
AI summary
A method for operating a power tool is provided. The power tool has a tool, in particular a drill bit, and a motor, while the motor is a brushless electric motor. In the power tool there is implemented a rotational speed graduation of an electronic form, with which a circumferential speed at the tool of the power tool can be kept essentially constant, while a rotational speed spread DELTA_n of greater than 2 is achieved by the design, dimensioning and/or control of the motor. Also provided is a tool device, for example a core drilling device, with which the proposed method can be carried out. An essential advantage of the invention is that the rotational speed spread DELTA_n of greater than 2 is achieved without a mechanical transmission on the power tool. Instead, a rotational speed graduation of an electronic form is used in the present invention.