Integrated Electromagnetic Brake for Electric Motor
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Solution Overview
Problem
Existing power tools with electric motors lack an efficient mechanism to quickly and reliably stop or slow the output shaft, which is crucial for applications like rotary hammers and cutting tools where rapid control over motor output is necessary.
Innovation Solution
A braking mechanism is integrated into the electric motor, comprising an electromagnet and two braking members – a co-rotating braking pad and a rotationally fixed brake member – that can be selectively engaged to frictionally slow or stop the motor shaft through controlled movement between release and braking positions, utilizing magnetic attraction and a compression spring for axial movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a brake mechanism is added to the electric motor, then the motor can stop or slow the output shaft rapidly, but the device complexity increases
Solution Approach 1:
The brake mechanism is integrated into the motor structure by combining the brake member with the motor housing and the braking pad with the output shaft assembly. This merging of functions allows rapid braking capability while minimizing additional complexity by using existing motor components as part of the brake system.
Solution Approach 2:
The electromagnet serves dual functions: it acts as both a brake actuator and can be part of the motor's control system. The brake member is designed to work with the motor housing structure, making the same structural elements serve both motor support and brake application functions.
2Ease of operation
If an electromagnet and spring system are used for brake actuation, then precise and rapid brake control is achieved, but the manufacturing complexity increases
Solution Approach 1:
The compression spring is pre-loaded during assembly to provide the necessary braking force. The electromagnet is pre-positioned and connected to the control system, allowing rapid response when activation is required. This preliminary setup enables precise control without requiring complex real-time adjustments during operation.
Solution Approach 2:
The compression spring automatically provides the counterforce needed for brake engagement without requiring additional actuators or control systems. The electromagnet's magnetic field self-generates the force needed to compress the spring and engage the brake, eliminating the need for external force application mechanisms.
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 rapid and precise control over motor rotation, allowing the motor to stop or slow within milliseconds, enhancing the performance and safety of power tools by providing quick braking capabilities.
Implementation Method 1
an electromagnet configured to be selectively energized in response to a control signal... When the electromagnet is energized, the electromagnet causes the first braking member to move from the first position to the second position
Implementation Method 2
utilizing magnetic attraction and a compression spring for axial movement
Implementation Method 3
a braking pad that rotates with the output shaft of the motor and a brake member that can frictionally engage the braking pad
Data Source
AI summary
A braking mechanism for an electric motor includes an electromagnet configured to be selectively energized in response to a control signal. The braking mechanism also includes a first braking member coupled for co-rotation with an output shaft of the electric motor. The first braking member is configured to movable relative to the output shaft between a first position and a second position. The braking mechanism also includes a second braking member rotationally fixed relative to the first braking member. When the electromagnet is energized, the electromagnet causes the first braking member to move from the first position to the second position. The first braking member engages the second braking member to brake the electric motor in one of the first position or the second position.