Rotating Machine Damping Collar With Cut Slats
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Solution Overview
Problem
Existing damping collars for rotating machines, such as turbomachines, face challenges in ensuring radial stability and absorbing vibrations at high speeds due to low external damping, leading to potential overloading and contact issues between rotating and fixed parts, with manufacturing processes being imprecise and non-reproducible.
Innovation Solution
A damping collar comprising a flexible metallic band with cut lamellae shaped into a ring, where the lamellae move outward to contact the fixed part, providing adjustable stiffness and damping without the need for shaping processes, allowing precise estimation and reproducibility of mechanical characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional forming processes with heat treatment and stamping are used to manufacture damping collars, then the collar can be produced, but the dimensional and mechanical characteristics cannot be precisely estimated and reproduction is poor
Solution Approach 1:
The collar is segmented into multiple slats cut from a flexible band, allowing each slat to deform independently. This segmentation enables precise control of mechanical characteristics through slat geometry while simplifying manufacturing to basic cutting and forming operations, eliminating complex heat treatment and stamping processes
Solution Approach 2:
The invention changes the manufacturing approach from thermal-mechanical processing to geometric parameter control. By precisely controlling slat dimensions, spacing, and band thickness during fabrication, the collar's dimensional and mechanical characteristics can be accurately estimated and reproduced without relying on imprecise heat treatment and stamping processes
2Reliability
If damping collars are used to provide damping to rotating parts, then vibrations can be absorbed, but the manufacturing process is not precise and does not allow accurate estimation of characteristics
Solution Approach 1:
The collar geometry is pre-designed with specific slat dimensions and spacing that directly determine the damping and stiffness characteristics. This preliminary geometric configuration allows accurate estimation of mechanical properties before assembly, eliminating the need for post-manufacturing adjustments or complex characterization of traditionally formed collars
Solution Approach 2:
The invention transitions from controlling damping through imprecise forming processes to controlling it through precise geometric parameters of the slats. By varying slat width, length, thickness, and spacing, the damping and stiffness can be accurately predicted and reproduced, enabling reliable estimation of mechanical characteristics
3Stability of the object's composition
If corrugations are compressed between bearing and housing during assembly, then radial displacements can be absorbed, but the manufacturing steps are complex and not reproducible
Solution Approach 1:
The collar is divided into multiple slats that can deform radially independently when compressed between the bearing and housing. This segmentation provides effective radial displacement absorption while simplifying manufacturing, as the slats are created by straightforward cutting operations rather than complex forming and heat treatment processes
Solution Approach 2:
The collar transitions from a rigid structure to a dynamic, deformable structure through the introduction of slats. During operation, the slats flex radially to absorb vibrations and radial displacements, providing the necessary stability while maintaining simple, reproducible manufacturing through basic cutting and forming operations
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 enhances damping performance by allowing accurate estimation and reproducibility of dimensional and mechanical characteristics, providing optimal damping and reducing vibrations through the natural separation of slats, which behave like springs, and generates dry friction for effective damping.
Implementation Method 1
the slats to be spread outwards from the collar so that the free edges of said slats are in contact with said fixed part... the strips act like springs
Implementation Method 2
the vibrations of the rotating part cause the free ends of the strips in contact with the fixed part to move; the resulting dry friction provides damping
Data Source
Figure 1
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Figure 4
AI summary
The invention concerns a rotating machine comprising: • - a fixed portion and a rotating portion, • - at least one bearing (20) provided with a fixed ring and a rotating ring mounted between said fixed portion and said rotating portion in order to guide the rotating portion in rotation, and • - a damping collar (12) interposed between the fixed ring of said bearing and the fixed portion. According to the invention, said damping collar comprises a flexible band (121) into which strips (122) have been cut, and this flexible band (121) is shaped into a ring around the fixed ring of said bearing (20), the shaping of the band into a ring causing the strips (122) to move towards the outside of the collar (12) such that the free edges (123) of said strips (122) are in contact with said fixed portion, said bearing (20) is housed in a tubular cylindrical insert (18) and said damping collar (12) is fixed directly to said tubular cylindrical insert (18).