Bistable Electromagnetic Clutch With Zero-Hold Power Engagement

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Solution Overview

Problem

Conventional electromagnetic clutches face issues such as unintended disconnection due to power loss, high energy consumption, and heat generation, which affect their performance and service life, particularly in new energy vehicles.

Innovation Solution

A bistable electromagnetic clutch design featuring a yoke with iron cores and electromagnetic coils, a moving carrier disc with magnets, and a spring mechanism that maintains separation or engagement without power consumption, utilizing grouped electromagnetic coils and magnets to form closed magnetic circuits and avoid magnetic leakage, along with a guide pin and induction coils for position control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If conventional electromagnetic clutch is used, then electromagnetic force can be generated to achieve engagement, but energy consumption and heat generation increase

Engineering Contradiction:
Improveelectromagnetic forceVSAvoidenergy consumption
Core Design Contradiction:
ForceVSUse of energy by moving object

Solution Approach 1:

The patent implements a bistable mechanism where the clutch can maintain two stable states (engaged and disengaged) without continuous power supply. The movable carrier disc with magnets interacts with the yoke and springs to create mechanical bistability, allowing the system to hold position dynamically without energy consumption, thus resolving the contradiction between generating electromagnetic force and reducing energy consumption

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The clutch system uses its own magnetic field and mechanical structure to maintain engagement state without external energy input. The magnets on the movable carrier disc create magnetic attraction to the yoke, while springs provide restoring force, enabling the system to self-maintain both engaged and disengaged states without continuous power supply, thereby eliminating energy consumption and heat generation

Inventive Principle:
Principle #25Self-service

2Reliability

If conventional electromagnetic clutch is used, then engagement can be achieved, but unintended open occurs due to power loss

Engineering Contradiction:
Improveengagement stabilityVSAvoidpower dependency
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The bistable mechanism creates two stable equilibrium positions: one where the movable carrier disc is attracted to the yoke (engaged state) and another where springs push it away (disengaged state). In both states, the system is mechanically self-sustaining without power, ensuring that power loss does not cause unintended opening, thus improving reliability while eliminating power dependency

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The spring mechanism pre-stores mechanical energy to counterbalance magnetic attraction force. When power is lost, the springs provide the necessary force to maintain the disengaged state or return the disc to disengaged position, preventing unintended engagement and ensuring fail-safe operation without continuous power supply

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

3Force

If electromagnetic coils are increased to improve electromagnetic force, then engagement force increases, but device complexity increases

Engineering Contradiction:
Improveelectromagnetic forceVSAvoidcoil structure
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The patent combines electromagnetic force generation with mechanical bistable structure. The electromagnetic coils are integrated with the yoke and movable carrier disc assembly, where the magnetic field works in conjunction with spring forces and magnetic attraction to achieve engagement. This merging allows the system to use fewer coils while maintaining sufficient engagement force through the synergistic effect of multiple physical mechanisms, thereby reducing device complexity

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 bistable design eliminates energy consumption and heat generation in both states, ensuring a fail-safe mechanism, improving safety and reliability, and achieving a lightweight, compact, and efficient electromagnetic clutch with reduced magnetic leakage and extended service life.

Implementation Method 1

an electromagnetic coil is provided on each of the iron cores... two electromagnetic coils in a same group are wound to form a group of windings with identical magnetic polarities

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

several magnets are fixed on the moving carrier disc, and the iron cores and the magnets are provided in a correspondence position/location... the corresponding two magnets form a group of magnetomotive forces with identical magnetic polarities

Methodology Applied
Scientific EffectMagnetism: Magnetism

Implementation Method 3

the spring part is configured to keep the moving carrier disc and the yoke in normally separated positions

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4180683B1Bistable electromagnetic clutch
Publication Date: 2023.11.08 JING JIN ELECTRIC TECH CO LTD
  • EP4180683B1 patent drawingFigure 1

AI summary

A bistable electromagnetic clutch is disclosed, which comprises a first part, a second part and an spring part. The first part comprises a yoke, the yoke is provided thereon with a plurality of iron cores (2), and an electromagnetic coil (3) is provided on each of the iron cores (2). The second part comprises a moving carrier disc (4) and a magnetic conductive disc (5), the magnetic conductive disc (5) is fixed on a side of the moving carrier disc (4) that is away from the yoke. Several magnets (6) are fixed on the moving carrier disc (4), and the iron cores (2) and the magnets (6) are provided in a correspondence relation. The spring part is configured to keep the moving carrier disc (4) and the yoke in normally separated positions. Two adjacent electromagnetic coils (3) form a group, two electromagnetic coils (3) in a same group are wound to form a group of windings with identical magnetic polarities, and corresponding two magnets (6) form a group of magnetomotive forces with identical magnetic polarities. The bistable electromagnetic clutch does not need to be powered on or consume any other form of energy both in the disengaged state and in the engaged state, and thus has the advantages of no energy consumption, no heat generation and long service life. Moreover, it has high electromagnetic utilization rate and no magnetic flux leakage.