Magnetic Decoupler for Vehicle Drive Shaft Torque Control

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Solution Overview

Problem

Existing decouplers for motor vehicle drive shafts and belt pulleys fail to effectively prevent unwanted torque transmission irregularities while minimizing noise emission.

Innovation Solution

A decoupler design featuring first and second ramp rings with push and pull ramps, a spring arrangement, and a specific geometry to allow torque transmission in drive mode while preventing it in coasting mode, using a free-wheel mechanism to avoid braking and noise, and incorporating a friction-reducing material for low noise emission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a decoupler uses a free-wheel mechanism to prevent torque transmission in coasting mode, then unwanted torque transmission irregularities are avoided, but noise emission increases due to mechanical engagement and disengagement

Engineering Contradiction:

Improvetorque transmission uniformityVSAvoidnoise emission

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent replaces the traditional mechanical free-wheel mechanism with a magnetic coupling system using permanent magnets and electromagnets. The magnetic coupling allows for smooth engagement and disengagement without mechanical contact, eliminating the noise generated by traditional ratchet and pawl mechanisms while maintaining the one-way torque transmission function. The magnetic field can be precisely controlled to engage or disengage the coupling without mechanical impact or friction.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If a decoupler uses a mechanical free-wheel mechanism, then torque transmission can be blocked in coasting mode, but the complexity of the device increases

Engineering Contradiction:

Improvecoasting mode decouplingVSAvoidmechanical structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent substitutes complex mechanical components (ramps, lugs, spring arrangements) with a magnetic field-based system. The coupling and decoupling functions are achieved through controlled magnetic fields from permanent magnets and electromagnets, eliminating the need for mechanical free-wheel mechanisms, springs, and ramp structures. This significantly reduces device complexity while maintaining the same functional outcomes.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The magnetic coupling system serves multiple functions: it provides torque transmission in drive mode, acts as a decoupler in coasting mode, and can be precisely controlled through the electromagnets. The permanent magnets provide the base coupling force while electromagnets enable active control, combining multiple functions into a single integrated system rather than requiring separate mechanical mechanisms for each function.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If a decoupler uses spring arrangements and ramp rings, then torque transmission can be controlled, but the device size and volume increase

Engineering Contradiction:

Improvetorque control capabilityVSAvoiddecoupler volume

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

The patent replaces bulky mechanical components (spring arrangements, ramp rings, multiple lugs) with a compact magnetic field system. The magnetic coupling achieves torque control without requiring large mechanical structures, as the magnetic field can be generated within a much smaller volume using permanent magnets and electromagnet coils. This dramatically reduces the overall decoupler volume while maintaining torque control capability.

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 decoupler effectively prevents unwanted torque transmission irregularities and reduces noise emission by allowing the belt pulley to decouple from the drive shaft in coasting mode, ensuring uniform operation of auxiliary assemblies with minimal noise.

Implementation Method 1

at least one spring arrangement for axial compression of the first ramp ring and of the second ramp ring

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

The first ramp ring has a first push ramp directed toward the second ramp ring and/or the second ramp ring has a second push ramp directed toward the first ramp ring. The first push ramp and/or the second push ramp is sloped in the circumferential direction relative to the axial direction

Methodology Applied

Scientific EffectFriction: Friction

Data Source

PatentUS9528590B2Decoupler for damping a torque transmission between a drive shaft of a motor vehicle and a belt pulley

Publication Date: 2016.12.27 SCHAEFFLER TECHNOLOGIES AG & CO KG

AI summary

A decoupler for damping torque transmission irregularities between a vehicle drive shaft and a belt pulley for driving vehicle auxiliary components. The decoupler includes first and second ramp rings for transmitting torque delivered by the drive shaft to the belt pulley. A spring arrangement provides for axial engagement of the ramp rings. The ramp rings have respective sloped push and pull ramps directed toward the adjacent ramp ring so that in a coasting mode of the vehicle the ramp rings rotate relative to each other and in a vehicle drive mode the ramp rings are drawn toward one another. The decoupler includes a pulley damper for damping torque transmission irregularities to reduce noise emission.