Electromagnetic Brake Assembly With Conical Interface for High Holding Torque
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Solution Overview
Problem
Conventional braking mechanisms in powered mobility assistance devices are noisy, bulky, and provide limited holding torque, making them unsuitable for individuals with impairments short of complete paralysis, as they are designed for more severe impairments and are not optimized for smaller and lighter systems.
Innovation Solution
A low-profile, quiet, and powerful controllable electromagnetic brake assembly with an integrated solenoid coil and friction components, located within the motor rotor, providing high holding torque with minimal electrical power input and featuring a conical interface with O-rings or interlocking teeth for enhanced friction and wear performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If conventional braking mechanisms are used in powered mobility assistance devices, then holding torque can be provided, but the device becomes noisy, bulky, and heavy
Solution Approach 1:
The brake assembly is integrated within the motor rotor structure, combining the braking function with the existing motor components. The armature is positioned within the rotor and shares the same magnetic circuit, eliminating the need for separate brake housing and reducing overall weight
Solution Approach 2:
The brake components are nested within the motor rotor. The armature is positioned inside the rotor assembly, and the brake stator is integrated with the rotor structure, creating a compact nested arrangement that reduces the overall footprint and weight of the braking mechanism
2Force
If conventional braking mechanisms are used in powered mobility assistance devices, then holding torque can be provided, but the device becomes noisy
Solution Approach 1:
A damper is incorporated into the brake assembly to cushion and absorb vibrations and impacts during brake engagement and operation. This dampening element reduces noise generation by preventing direct transmission of mechanical shocks and vibrations to the surrounding structure
3Force
If conventional braking mechanisms are used in powered mobility assistance devices, then holding torque can be provided, but the device size increases
Solution Approach 1:
The brake assembly utilizes the motor rotor's magnetic circuit and structural components, merging the braking function with the existing motor assembly. This integration eliminates the need for separate brake housing, armature mounting structures, and magnetic circuits, significantly reducing the overall volume
Solution Approach 2:
The brake components are arranged in an axially-concentric configuration within the rotor, utilizing the radial and axial dimensions efficiently. The armature is positioned radially within the rotor, and the magnetic flux paths are optimized in three dimensions to maximize holding torque while minimizing the volume occupied by brake components
4Force
If electric motors operate at extremely low speeds for human walking, then torque output can be maximized, but efficiency decreases significantly
Solution Approach 1:
The brake assembly acts as an intermediary device that provides holding torque during the swing phase of gait, reducing the duty cycle and power requirements of the electric motor. By handling the static holding torque requirement, the brake allows the motor to operate more efficiently during dynamic phases
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 brake assembly effectively stabilizes human limbs during walking, reducing electrical power requirements and enabling longer battery life, while being compact and quiet, making it suitable for KAFO and HKAFO devices.
Implementation Method 1
a solenoid coil; a fixed ferrous brake stator; a ferrous armature moveable in a translation direction relative to the brake stator between a disengaged position and an engaged position
Implementation Method 2
the braking face of the armature interacts with the mating surface of the rotating member to apply a braking force to the rotating member
Data Source
AI summary
An electromagnetic brake assembly includes a solenoid coil; a fixed ferrous brake stator; a ferrous armature having a braking face, wherein the armature is moveable in a translation direction relative to the brake stator between a disengaged position and an engaged position; and a rotating member including a mating surface and that rotates relative to the armature when the armature is in the disengaged position. When the solenoid coil is energized, the armature translationally moves from the disengaged position to the engaged position, and in the engaged position the braking face of the armature interacts with the mating surface of the rotating member to apply a braking force to the rotating member. The braking face and the mating surface may form a conical interface, and the conical interface further may include a friction O-ring positioned within a slot that permits the O-ring to roll along the braking interface when the armature moves between the disengaged position and the engaged position.