Turbomachine Bearing Attachment Using Reverse-Threaded Screws
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Solution Overview
Problem
The existing attachment method of bearings on turbomachines is prone to connection loss due to unbalanced rotor vibrations, leading to potential damage and failure of the turbomachine components.
Innovation Solution
Using screws with a screwing direction opposite to the rotor's rotation direction to prevent unscrewing caused by vibrations and allowing for self-screwing due to unbalance effects, with the option of reversing the bolt layout or using left-hand screws.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional screws are used for attaching the bearing, then the attachment method is simple, but the connection may be lost due to rotor vibrations and unbalance
Solution Approach 1:
The patent applies inversion by using left-handed screws instead of conventional right-handed screws. This reverses the screwing direction to counteract the unscrewing effect caused by rotor vibrations and unbalance, thereby improving connection reliability without significantly increasing device complexity
Solution Approach 2:
The patent applies preliminary anti-action by pre-selecting screws with opposite handedness to the vibration-induced unscrewing direction. This preliminary counter-measure prevents connection loss before it occurs, addressing the reliability issue proactively rather than reactively
2Reliability
If the screwing direction matches the rotor rotation direction, then the assembly is straightforward, but vibrations may cause unscrewing and connection loss
Solution Approach 1:
The patent inverts the conventional approach by using left-handed screws instead of right-handed screws. This reversal ensures that the screwing direction opposes the unscrewing tendency caused by rotor vibrations, maintaining attachment security while keeping the assembly process relatively simple
3Reliability
If standard right-handed screws are used, then the components are readily available, but unbalance effects may cause connection loss
Solution Approach 1:
The patent uses left-handed screws which are less common but still readily available standardized components. This inversion provides connection stability against unbalance effects while not significantly increasing the quantity or specialization of components required
Solution Approach 2:
The patent changes the handedness parameter of the screws from conventional right-handed to left-handed. This parameter change fundamentally alters the screw's response to rotational vibrations, improving connection stability without requiring exotic or specialized components
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
Enhances the reliability and robustness of the bearing attachment by preventing unscrewing and ensuring secure fixation, even under unbalanced conditions, thereby reducing the risk of turbomachine component damage.
Implementation Method 1
unscrewing thereof by communication of vibrations due to an unbalance of the rotor of the turbomachine is avoided
Implementation Method 2
allows an auto-screwing of the screws to be achieved thanks to the effects of the rotor unbalance
Data Source
AI summary
A method for attaching a bearing on a turbomachine including a stator and a rotor, the bearing including: a first portion attached on the stator of the turbomachine by a plurality of screws and nuts, a second portion attached on the rotor, rotationally movable in one given rotation direction, and a rolling bearing provided between the first and second portions of the bearing is disclosed. The method provides using screws having a screwing rotation direction contrary to the rotation direction of the rotor.