Power Tool Switch Module With Hall Sensing and Low-Heat H-Bridge Control
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Solution Overview
Problem
Conventional power tool switch modules require significant space due to mechanical components, are prone to wear, and generate excessive heat, necessitating large heat sinks, which increases the size and weight of the tools.
Innovation Solution
An electronic switch module incorporating a programmable micro-controller and power components in a single housing, utilizing H-bridge configurations with synchronous rectification to reduce heat dissipation and eliminate mechanical switches, and employing IMS boards for efficient heat management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If mechanical switches and components are used in the switch module, then the tool can be controlled for direction and speed, but the space occupied by mechanical components increases the size of the tool
Solution Approach 1:
The patent replaces mechanical switches with electronic switching components including MOSFETs arranged in H-bridge configurations. The mechanical commutator and brush system is substituted with electronic control circuits that use voltage signals from a potentiometer to control the switching of power components, thereby eliminating the need for mechanical moving parts while maintaining control functionality.
Solution Approach 2:
The patent integrates multiple control functions (forward/reverse direction control and variable speed control) into a single unified switch module. The H-bridge configuration with electronic switching components can perform both direction reversal and speed regulation through different switching patterns, eliminating the need for separate mechanical switches for each function.
2Ease of operation
If mechanical switches are used in the switch module, then control functionality is achieved, but wear and reliability issues occur
Solution Approach 1:
The patent eliminates mechanical switches by using solid-state electronic components (MOSFETs) for switching. The mechanical commutator and brush system that is prone to wear and contact degradation is replaced with an electronic control system that uses voltage signals to control the switching of power components, significantly improving reliability and durability.
3Power
If conventional power components are used, then power control is achieved, but excessive heat is generated requiring large heat sinks
Solution Approach 1:
The patent replaces conventional power components with advanced MOSFETs arranged in H-bridge configurations that offer lower on-resistance and more efficient switching characteristics. This substitution reduces power losses and heat generation while maintaining full power control capability, allowing for smaller heat sink requirements.
Solution Approach 2:
The patent changes the electrical parameters of the power control system by using MOSFETs with optimized resistance characteristics and switching speeds. The H-bridge configuration allows for more efficient power delivery with reduced I²R losses, and the electronic control enables precise modulation of power delivery to minimize heat generation while maintaining required power output.
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 reduces heat dissipation by a factor of 13.8, allowing for a 44% reduction in heat sink size, thus minimizing the tool's overall size and weight while maintaining efficient power control.
Implementation Method 1
A set of sense magnets coupled to the PMs in the rotor assembly are sensed by a sensor, such as a Hall Effect sensor, to identify the current position of the rotor assembly.
Implementation Method 2
When power is applied to a winding, the resulting current in the winding generates a magnetic field that couples to the rotor. The magnetic field associated with the PM in the rotor assembly attempts to align itself with the stator generated magnetic field resulting in rotational movement of the rotor.
Data Source
AI summary
An electronic switch module for a power tool is provided including a module body, a trigger moveable relative to the module body, a magnet being moveable relative to the module body with the trigger along a movement axis, and a linear Hall sensor fixed relative to the module body and intersecting the movement axis of the magnet. The linear Hall sensor magnetically detects a linear position of the magnet along the movement axis and outputs a voltage signal based on the detected linear position.