Electric Hand Tool Electromagnetic Brake Control Method
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional electric hand tools, such as grinding machines, face issues with grinding quality degradation and increased motor burden due to constant contact between a damping body and the grinding disc, leading to wear and pollution, as well as inefficient braking mechanisms that prolong rotor inertia.
Innovation Solution
An electromagnetic brake control method is introduced, where a short circuit is created between coils and a driving module in the electric motor, allowing the motor to enter a power generating state and utilize magnetic fields to create a repulsive force for braking, eliminating the need for a damping body and simplifying the tool's structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a damping body is used to decelerate the grinding disc, then the rotational speed can be reduced after motor shutdown, but the grinding quality is degraded and wear occurs between the damping body and contact plane
Solution Approach 1:
The patent replaces the mechanical damping body system with an electromagnetic braking system. The electromagnetic brake uses magnetic fields to generate braking force on the rotor, eliminating the need for physical contact between a damping body and the grinding disc. This substitution resolves the contradiction by providing speed control without mechanical wear and quality degradation.
Solution Approach 2:
The patent introduces an electromagnetic field as an intermediary between the motor control system and the rotating components. The electromagnetic brake creates a magnetic field that interacts with the rotor to produce braking force, serving as a non-contact mediator that controls rotational speed without direct mechanical contact, thereby avoiding wear and grinding quality issues.
2Reliability
If a damping body is used to decelerate the grinding disc, then braking function is provided, but wear is caused by abrasion between the damping body and contact plane requiring regular replacement
Solution Approach 1:
The patent replaces the mechanical contact-based braking system with an electromagnetic braking system. The electromagnetic brake uses magnetic fields to produce braking force without physical contact between moving parts, eliminating wear and the need for regular component replacement while maintaining reliable braking function.
Solution Approach 2:
The electromagnetic braking system is integrated into the motor structure itself, with the brake coils and permanent magnets forming part of the motor assembly. This self-contained design eliminates separate wear-prone components like damping bodies and contact planes, reducing maintenance needs while providing continuous reliable braking.
3Speed
If a damping body is used to decelerate the grinding disc, then rotational speed control is achieved, but the structure becomes more complex and adds burden to the electric motor
Solution Approach 1:
The patent merges the braking function with the motor structure by integrating electromagnetic brake coils and permanent magnets into the motor assembly. This combination eliminates the need for separate mechanical braking components like damping bodies and contact planes, simplifying the overall structure while providing effective rotational speed control.
Solution Approach 2:
The electromagnetic braking system serves multiple functions: it provides braking force, controls rotational speed, and is integrated into the motor structure. This multi-functional design eliminates the need for separate dedicated braking components, reducing structural complexity while achieving speed 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 effectively stops the rotor without degrading grinding quality, reduces wear, and simplifies the tool's design by using electromagnetic braking, improving operational efficiency and reducing maintenance needs.
Implementation Method 1
the rotor is caused to continue rotating relative to the stator, such that the electric motor is caused to temporarily enter a power generating state to generate a sensing current. The coils receive the sensing current to establish a first magnetic field.
Implementation Method 2
The first magnetic field interferes with a second magnetic field produced by a plurality of permanent magnets provided at the electric motor to form an interfering repulsive force that stops the rotor from rotating.
Implementation Method 3
The first magnetic field interferes with a second magnetic field produced by a plurality of permanent magnets provided at the electric motor to form an interfering repulsive force that stops the rotor from rotating.
Data Source
AI summary
An electric hand tool is provided. The electric hand tool receives a shutdown signal issued by a shutdown element under control during an operation process of the electric hand tool, so as to request a driving module to stop providing a driving signal to a plurality of coils provided at the electric motor, and to conduct a brake loop connected to the coils and the driving module. Thus, a short circuit is formed between the coils and the driving module to cause the electric motor to temporarily enter a power generating state to generate a sensing current. The coils receive the sensing current to establish a first magnetic field. The first magnetic field interferes with a second magnetic field produced by a plurality of permanent magnets to form an interfering repulsive force that stops the rotor from rotating, thereby achieving an object of braking promptly.