Sleeve-Shaped Permanent Magnet Electromagnetic Brake Torque
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Solution Overview
Problem
Conventional electromagnetic brakes with annular disc-shaped permanent magnets face limitations in generating a high braking moment due to their radial extent, which restricts their installation and performance, especially in terms of torque and air window of exciting current.
Innovation Solution
The electromagnetic brake features a permanent magnet with a radial cross-sectional dimension smaller than its axial dimension, arranged axially between the armature disc and the exciting coil, allowing for increased magnetic force without expanding the brake's cross-sectional area, and can be configured in a sleeve-shaped or collar-shaped form to enhance magnetic flux and torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the radial extent of the annular disc-shaped permanent magnet is increased to increase the braking moment, then the braking torque increases, but the cross section of the brake increases beyond the available installation space
Solution Approach 1:
The permanent magnet is changed from a radially extended disc shape to an axially extended sleeve shape. The magnetic force is generated through axial extension rather than radial extension, allowing the braking torque to increase without increasing the radial cross-section of the brake. The sleeve-shaped magnet extends in the axial direction between the armature disc and exciting coil, utilizing the axial dimension to achieve the required braking moment while maintaining a compact radial profile.
2Power
If the permanent magnet is configured with radial cross-sectional dimension smaller than axial dimension, then the magnetic force and torque increase, but the air window of exciting current may be reduced
Solution Approach 1:
The invention changes the geometric parameters of the permanent magnet from a disc configuration (larger radial dimension) to a sleeve configuration (larger axial dimension). This parameter change allows the magnetic flux to be concentrated more effectively through the pole pieces and armature disc, increasing the braking torque. The sleeve shape with smaller radial cross-section actually helps maintain a larger air window by reducing the radial space requirements and allowing for better magnetic circuit design that accommodates a wider range of exciting currents.
3Power
If the permanent magnet is arranged axially between the armature disc and exciting coil, then the magnetic flux path is shortened and torque is increased, but the spatial arrangement becomes more constrained
Solution Approach 1:
The invention merges the permanent magnet into the brake body structure as an integrated component. The sleeve-shaped permanent magnet is positioned axially between the armature disc and exciting coil, forming a unified magnetic circuit assembly. This integration shortens the magnetic flux path and improves torque efficiency while the modular design allows for straightforward assembly and maintenance, balancing the spatial constraints with ease of implementation.
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 configuration significantly increases the braking torque while maintaining a large air window of exciting current, allowing for improved temperature response and reduced size, with the potential for a double brake setup using two permanent magnets and armature discs on either side of the exciting coil.
Implementation Method 1
the armature disc can be drawn against the brake body by the magnetic force of the permanent magnet
Implementation Method 2
the electromagnet compensates, neutralizes, displaces, or deflects the magnetic field of the permanent magnet at least to the extent that the armature disc can be or is lifted from the brake body via the spring force
Implementation Method 3
the restoring spring constructed, for example, as a leaf spring, pulls the armature disc away from the poles
Data Source
AI summary
An electromagnetic brake (20), in particular for an electric drive is provided, having a brake body (3), which is provided with a sleeve-shaped permanent magnet (4), an electromagnet (5) with an exciting coil (6), an external ring in the form of an external pole and an internal ring (8) in the form of an internal pole, wherein an armature disc (12) rotatably connected to a shaft is attractable against the brake body (3) or the external or internal ring surfaces by the permanent magnet (4) force acting against a return spring force. When the exciting coil is powered, the permanent magnet (4) magnetic field is compensated in such a way that the armature disc (12) is lifted up from the brake body (3) by the spring force, thereby allowing the brake to be released. A radial cross-sectional dimension or cross-sectional thickness d of the permanent magnet (4) is smaller than the axial dimension thereof and a spatial arrangement, viewed in the axial direction, is provided between the armature disc (12) and the exciting coil (6) in the area radially external with respect to the exciting coil (6) or the housing thereof.