Bistable Brake Assembly Using Magnets and Springs

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Solution Overview

Problem

Existing brake technologies consume excessive electrical energy and are not environmentally friendly, as they require continuous power to maintain the brake state, leading to resource wastage and environmental impact.

Innovation Solution

A bistable brake assembly where only state changes require electrical energy, utilizing a coil connected in series with a capacitance and permanent magnets to maintain the brake states without continuous power, with a feather key connection and spring elements generating frictional force for braking, allowing the brake to be environmentally friendly and energy-efficient.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If continuous electrical power is supplied to maintain brake state, then brake reliability is improved, but energy consumption increases

Engineering Contradiction:
Improvebrake state stabilityVSAvoidelectrical energy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The brake system uses periodic electrical pulses instead of continuous power supply. The coil is energized only during state transitions (venting or collapsing), and the capacitor stores energy to maintain the magnetic field temporarily. This periodic action reduces energy consumption while maintaining brake state stability through the bistable mechanism.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The brake system utilizes its own mechanical structure to maintain states without continuous external energy input. The spring elements and magnetic field create a self-sustaining bistable system where the brake remains in either vented or collapsed state without power, and only requires energy for state changes. The feather key connection also provides self-aligning features that reduce maintenance energy requirements.

Inventive Principle:
Principle #25Self-service

2Force

If air gap is reduced for stronger magnetic flux, then magnetic force is improved, but manufacturing precision requirements increase

Engineering Contradiction:
Improvemagnetic attractive forceVSAvoidair gap tolerance
Core Design Contradiction:
ForceVSManufacturing precision

Solution Approach 1:

The system incorporates a feather key connection that provides pre-alignment and cushioning between the armature disk and the hub. This mechanical cushioning compensates for manufacturing tolerances and ensures consistent air gap dimensions without requiring extremely tight manufacturing precision. The feather key absorbs dimensional variations and maintains reliable magnetic coupling.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Force

If spring force is increased to maintain collapsed state, then braking force is improved, but mechanical stress increases

Engineering Contradiction:
Improvebraking forceVSAvoidspring mechanical stress
Core Design Contradiction:
ForceVSStress or pressure

Solution Approach 1:

The system merges the spring force with the magnetic force to maintain the collapsed braking state. During normal braking, both the spring elements and the permanent magnets work together to press the brake pads against the rotating element. This combination allows the spring force to be reduced compared to a purely mechanical system, as the magnetic field provides additional holding force, thereby reducing mechanical stress on the spring components.

Inventive Principle:
Principle #5Merging (Combining)

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 operates with minimal electrical energy usage, maintaining both ventilated and collapsed states without electricity, conserving energy and protecting the environment, while ensuring effective braking through magnetic and spring forces.

Implementation Method 1

the brake can be released by energizing a coil of the brake

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a magnetic field is generated by permanent magnets arranged at a non-vanishing radial distance from a rotation axis of the shaft to be braked

Methodology Applied
Scientific EffectMagnetism: Magnetism

Implementation Method 3

The magnetic field generated by the permanent magnets amplifies the magnetic field generated by the coil when it is energized

Methodology Applied
Scientific EffectMagnetic field amplification: Magnetic Amplifier

Implementation Method 4

the armature disk is pressed by the spring elements onto the brake pad carrier in the collapsed state

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 5

the brake pad carrier is pressed onto the braking surface, frictional force is generated on both sides of the brake pad carrier

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3298297B1Brake arrangement and method for operating a brake arrangement
Publication Date: 2021.08.25 SEW EURODRIVE GMBH & CO KG
  • EP3298297B1 patent drawingFigure 1
  • EP3298297B1 patent drawingFigure 2

AI summary

The invention relates to a brake arrangement and a method for operating a brake arrangement comprising the following: - an armature disc, - a coil core, - a coil, - a brake lining support, - a part which has a braking surface, in particular a bearing plate, - permanent magnets, - a shaft, and - a driver. The armature disc is arranged in a rotationally fixed but axially movable manner relative to the coil core, and the coil, the coil core, and the part which has a braking surface are connected, in particular in a rigid manner. The shaft is rigidly connected to the driver, and the driver has an outer toothing which meshes with an inner toothing of the brake lining support such that the brake lining support is connected to the driver and thus to the shaft in a rotationally fixed but axially movable manner. The brake arrangement can be brought into a release state or an engaged state. In the release state of the brake arrangement, the armature disc is arranged closer to the coil than in the engaged state of the brake arrangement, wherein a spring force generated by spring elements acts on the armature disc; the permanent magnets are arranged such that the armature disc can be held by the permanent magnets in the release state; and the armature disc is held by the spring force in the engaged state.