Exhaust Valve Coupling Assembly for Misalignment Without Angular Play

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Solution Overview

Problem

Existing exhaust-gas valve systems face issues with misalignment due to manufacturing errors and thermal stress, leading to unreliable positioning, rattling noise, and premature failure under high thermal loads, especially in performance exhaust systems.

Innovation Solution

A coupling device with a torsionally rigid retainer and a non-rotatable connection between the drive and driven shafts, using a compressible or stretchable elastic element to compensate for misalignment and thermal expansion, ensuring precise positioning and reducing noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

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

Engineering Contradiction:

Improvemisalignment compensationVSAvoidvalve positioning precision

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The coupling device is divided into two independent functional segments: a rigid retainer for precise torque transmission and positioning, and a separate elastic element for misalignment compensation. This segmentation allows each component to perform its specific function optimally without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The elastic element acts as an intermediary between the drive shaft and driven shaft, absorbing misalignment and thermal expansion while the rigid retainer maintains precise positioning. The elastic element mediates the conflicting requirements of adaptability and precision.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If a rigid spring connection is used, then positioning precision is improved, but reliability deteriorates under high thermal loads

Engineering Contradiction:

Improvevalve positioning precisionVSAvoidstructural integrity under thermal stress

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The system transitions from a purely rigid connection to a hybrid connection that incorporates elastic properties. The elastic element's parameters (spring constant, material properties) are selected to provide sufficient rigidity for positioning while maintaining flexibility to handle thermal stress, thus adapting the connection's mechanical parameters to meet both requirements.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If an elastic member with angular play is used, then adaptability is improved, but harmful factors increase due to rattling noise

Engineering Contradiction:

Improvemisalignment compensationVSAvoidrattling noise

Core Design Contradiction:

Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

By separating the misalignment compensation function (elastic element) from the torque transmission function (rigid retainer), the system eliminates angular play in the torque transmission path. This segmentation prevents the rattling noise that would otherwise be generated by play in the connection.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The elastic element absorbs the harmful effects of misalignment and thermal expansion, converting what would be sources of noise and stress into controlled elastic deformation. The elastic element deforms to accommodate misalignment while the rigid retainer maintains stable torque transmission, thus converting potential harm into beneficial compliance.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

4Reliability

If a coil spring is used to bias the valve flap closed, then reliability is improved, but harmful factors increase due to damage to the valve flap

Engineering Contradiction:

Improvevalve closing reliabilityVSAvoidvalve flap damage

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The closing bias function is extracted from the coupling device and implemented as a separate mechanism (e.g., a return spring on the valve flap itself). This separation removes the harmful concentrated forces from the valve flap circumference that were caused by the coil spring's action in the coupling device.

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 coupling device provides reliable, precise positioning of the exhaust-gas valve, reduces rattling noise, and maintains structural integrity under thermal stress, enhancing system performance and compliance with noise emission criteria.

Implementation Method 1

The coupling device comprises an elastic element (4), in particular a spring, which is compressible or stretchable in an axial direction A between a drive shaft (31) of an actuator (3) and a driven shaft (51) of an exhaust-gas valve (5)

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Data Source

PatentUS12442460B2Coupling device, valve system and method for assembling a coupling device

Publication Date: 2025.10.14 AKRAPOVIC D D

AI summary

A Coupling device may be used to connect a drive shaft of an actuator to a driven shaft of an exhaust-gas valve. The coupling device may define a rotational axis and include a torsionally rigid retainer having an axially extending slot, a coupling rod received in the slot for translational movement relative to the retainer in the direction of the rotational axis, and an elastic element biasing the coupling rod in the direction of the rotational axis and having an attachment section fixed to the retainer. The retainer and the coupling rod may be non-rotatably connected.