Exhaust Valve Coupling With Cardanic Misalignment Compensation

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Solution Overview

Problem

Existing exhaust-gas valve systems face issues with misalignment due to manufacturing errors and thermal expansion, leading to unreliable valve positioning and unwanted noise, particularly under high thermal loads and rapid exhaust gas pulses.

Innovation Solution

A coupling device that connects the drive shaft of an actuator to the driven shaft of an exhaust-gas valve, featuring a torsionally rigid retainer with a slot and an elastic element, allowing for precise positioning and thermal decoupling, while preventing rotational play and reducing noise through a cardanic function.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a torsional spring is used to compensate misalignment, then adaptability is improved, but manufacturing precision deteriorates due to angular play

Engineering Contradiction:

Improvemisalignment compensationVSAvoidvalve positioning precision

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The coupling device is divided into three functional segments: a first element connected to the drive shaft, a second element connected to the driven shaft, and an elastic element connecting the first and second elements. This segmentation allows each component to perform its specific function while maintaining overall precision.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The elastic element acts as an intermediary component between the drive shaft and driven shaft, compensating for misalignment without introducing angular play. It mediates the connection by providing elastic deformation capability while maintaining precise torque transmission.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If an elastic spring directly couples the drive shaft to the driven shaft, then adaptability is improved, but reliability deteriorates under high thermal loads

Engineering Contradiction:

Improvethermal expansion compensationVSAvoidvalve positioning reliability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The elastic element is designed with specific local properties - it provides elasticity in the axial direction to compensate for thermal expansion, while maintaining high torsional rigidity in the rotational direction to ensure reliable valve positioning under thermal loads.

Inventive Principle:

Principle #3Local quality

3Ease of operation

If a coil spring with rectilinear sections is used, then ease of operation is improved, but device complexity increases

Engineering Contradiction:

Improveassembly simplicityVSAvoidcoupling device structure

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The elastic element functions as a flexible component that accommodates axial movements due to thermal expansion while maintaining structural integrity. Its elastic nature allows it to flexibly adapt to dimensional changes without requiring complex mechanical adjustments.

Inventive Principle:

Principle #30Flexible shells and thin films

4Reliability

If a torsional spring is used to bias the valve flap closed, then reliability is improved, but object-generated harmful factors increase due to rattling noise

Engineering Contradiction:

Improvevalve positioning reliabilityVSAvoidrattling noise

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The biasing function is extracted from the elastic element and implemented separately through the retainer structure. The retainer is configured to provide the closing bias on the valve flap, while the elastic element solely handles the compensation of axial misalignment, eliminating the source of rattling noise.

Inventive Principle:

Principle #2Taking out (Extraction)

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 improved reliability, precise positioning, and reduced noise by compensating for misalignment and thermal stresses, ensuring reliable operation under varying conditions.

Implementation Method 1

an elastic element (4) connecting the first element (22) to the second element (23), wherein the elastic element (4) is designed to compensate for misalignment between the drive shaft (31) and the driven shaft (51)

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Implementation Method 2

The coupling device (1) is designed to act as a cardanic coupling between the drive shaft (31) and the driven shaft (51), thereby compensating for angular misalignment

Methodology Applied

Scientific EffectCardanic motion: Gimbal

Implementation Method 3

thermal decoupling, while preventing rotational play and reducing noise

Methodology Applied

Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentEP4008892A1Coupling device, valve system and method for assembling a coupling device or a valve system

Publication Date: 2022.06.08 AKRAPOVIC D D

Figure 1~2c
Figure 3a~5c
Figure 6a~8c

AI summary

A Coupling device (1) for connecting a drive shaft (31) of an actuator (3) to a driven shaft (51) of an exhaust-gas valve (5). The coupling device (1) defines a rotational axis (A) and comprises a torsionally rigid retainer (2) having an axially extending slot (25), a coupling rod (45) received in the slot (25) for translational movement relative to the retainer (2) in the direction of the rotational axis (A), and an elastic element (4) biasing the coupling rod (45) in the direction of the rotational axis (A) and having an attachment section (42) fixed to the retainer (2); wherein the retainer (2) and the coupling rod (45) are non-rotatably connected.