Attachment ring for turbine wheel of an air treatment unit and air treatment unit comprising such an attachment element

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Solution Overview

Problem

Conventional fixing methods for turbine wheels in air treatment units, particularly those made of composite materials, face issues with long-term resistance and balance, leading to assembly breakdown and vibration due to the flexibility of composite materials and lack of effective balancing mechanisms.

Innovation Solution

A fixing element with a cylindrical passage and ribs for rotational locking, a screw shaft for translational locking, and optional balancing protrusions and reinforcement ribs, made from lightweight plastic materials like thermoplastic polymers with glass fibers, ensures secure attachment and balance of the turbine wheel.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional fixing methods (press-fit, collar, or sliding assembly) are used to secure a composite material turbine wheel to a metal shaft, then the assembly can be initially fixed, but the flexibility of composite material causes the assembly to break after a few hundred hours of operation

Engineering Contradiction:
Improvefixing strengthVSAvoidlong-term durability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent changes the geometric parameters of the fixing ring by adding axial ribs that engage with radial slots in the turbine wheel. This creates a multi-tooth engagement mechanism that distributes mechanical stress across multiple contact points, preventing the stress concentration that leads to breakage in conventional single-point fixing methods.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The fixing ring is made from a composite material consisting of thermoplastic polymer matrix reinforced with glass fibers. This composite structure provides both the flexibility needed to accommodate composite turbine wheel expansion and the strength required to maintain secure attachment over time, resolving the contradiction between initial fixing strength and long-term durability.

Inventive Principle:
Principle #40Composite materials

2Strength

If conventional fixing rings are used to secure the turbine wheel, then the wheel can be attached to the shaft, but the fixing rings generate imbalance which disrupts dynamic operation and accelerates breakage

Engineering Contradiction:
Improveattachment securityVSAvoidimbalance and vibration
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The patent applies local quality by adding balancing protrusions at specific locations on the fixing ring. These protrusions are strategically positioned to counterbalance the mass distribution, ensuring that the center of gravity remains on the rotational axis. This local modification eliminates imbalance and vibration while preserving the overall attachment security provided by the ribbed engagement mechanism.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP2960523B1Attachment ring for turbine wheel of an air treatment unit and air treatment unit comprising such an attachment element
Publication Date: 2019.12.11 CARRIER CORP
  • EP2960523B1 patent drawingFigure 1
  • EP2960523B1 patent drawingFigure 2
  • EP2960523B1 patent drawingFigure 3

AI summary

This fixing element (7) is provided for an air treatment unit turbine wheel, the air treatment unit comprising a motor driving in rotation, around an axis (X), a shaft, and a fastening element (7) of the turbine wheel on the shaft. The fixing element (7) is traversed by a passage (71) provided to cooperate with the motor shaft, the passage (71) and the shaft each being provided with a flat (73) for the blocking in rotation of the fixing element (7) with respect to the shaft. The fixing element (7) comprises ribs (73) for locking the fixing element (7) in rotation with respect to the turbine wheel, the ribs (73) being provided to cooperate with slots in the wheel turbine. The fixing element (7) comprises a shaft of screws (76), provided to cooperate with a pressure screw for the locking in translation of the fixing element (7) with respect to the motor shaft.