Electromagnetic Clutch Assembly Using Wrap Spring Actuation

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Solution Overview

Problem

Current clutches require significant power, complex components, and are sensitive to installation gaps, leading to high costs and installation challenges.

Innovation Solution

A clutch assembly using an electromagnet to generate a magnetic circuit that drives an armature to engage with clutch members, employing a wrap spring with helical coils and a carrier to connect rotating and stationary members efficiently, reducing power requirements and simplifying installation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional clutches are used to control the connection between drive and driven elements, then reliable power transmission is achieved, but significant power consumption and high current requirements occur

Engineering Contradiction:
Improvereliable power transmissionVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent replaces traditional mechanical clutch actuation systems with an electromagnetic field-based system. The electromagnet generates a magnetic field that directly actuates the armature, eliminating the need for mechanical linkages, springs, and cables. This substitution reduces power consumption while maintaining reliable engagement and disengagement of the clutch members.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent utilizes changes in electromagnetic field parameters (magnetic flux density, field strength) to control clutch engagement. By varying the electrical current through the electromagnet coil, the magnetic field strength is adjusted to either engage or disengage the clutch, providing efficient and reliable control with minimal power consumption compared to mechanical systems.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If traditional clutch components are used, then functional requirements are met, but device complexity and cost increase

Engineering Contradiction:
Improveclutch functionalityVSAvoidcomponent quantity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple traditional clutch components into an integrated electromagnetic actuation system. The electromagnet assembly (including coil, core, and yoke) replaces separate actuators, linkages, and adjustment mechanisms. The armature is integrated with the clutch member it actuates, reducing the total number of parts and simplifying the overall clutch construction while maintaining full functionality.

Inventive Principle:
Principle #5Merging (Combining)

3Power

If traditional clutch designs are used, then power transmission is achieved, but sensitivity to installation gaps makes installation difficult

Engineering Contradiction:
Improvepower transmission capabilityVSAvoidinstallation ease
Core Design Contradiction:
PowerVSEase of manufacture

Solution Approach 1:

The patent replaces mechanical gap-sensitive adjustment systems with an electromagnetic field system. The magnetic field can actuate the armature effectively over a range of positions, making the clutch less sensitive to installation gaps and alignment variations. This eliminates the need for precise shimming and adjustment during installation while maintaining effective power transmission.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 solution provides a low-power, compact clutch assembly with reduced component complexity, improved installation ease, and enhanced reliability by using an electromagnet to engage clutch members through a magnetic circuit, effectively addressing the limitations of existing clutches.

Implementation Method 1

An electromagnetic unit is provided and includes an electromagnet. Energization of the electromagnet generates a magnetic flux that flows through one of the first and second clutch members, through the armature and back into the electromagnetic unit.

Methodology Applied
Scientific EffectElectromagnet: Electromagnet

Implementation Method 2

Energization of the electromagnet generates a magnetic flux that flows through one of the first and second clutch members, through the armature and back into the electromagnetic unit.

Methodology Applied
Scientific EffectMagnetic flux: Magnetic Field

Implementation Method 3

the magnetic flux draws the armature axially into engagement with the other of the first and second clutch members with sufficient force to frictionally cause rotation of the armature and the second end of the wrap spring

Methodology Applied
Scientific EffectMagnetic force: Magnetic Field

Implementation Method 4

with sufficient force to frictionally cause rotation of the armature and the second end of the wrap spring relative to the first end of the wrap spring

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 5

so as to radially expand the wrap spring into engagement with the other of the first and second clutch members thereby operatively connecting the first clutch member to the second clutch member

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP2836733B1Clutch assembly
Publication Date: 2019.01.02 LITENS AUTOMOTIVE INC
  • EP2836733B1 patent drawingFigure 1
  • EP2836733B1 patent drawingFigure 2a
  • EP2836733B1 patent drawingFigure 2b

AI summary

In an aspect, a clutch assembly is provided that uses an electromagnet to generate a magnetic circuit which drives an armature to a position whereat it engages the clutch to operatively connect a rotating member to a stationary member. In embodiments wherein the armature initially rotates with the rotating member, the magnetic circuit passes through the stationary member. In embodiments wherein the armature is initially stationary, the magnetic circuit extends through the rotating member.