Lightened Plain Bearing Structure for Turbine Gear Vibration Control
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Solution Overview
Problem
The mass of plain bearings in mechanical reduction gears for turbomachines leads to unbalance, high vibrations, and radial forces, causing misalignments and inefficiencies due to friction losses and heat retention issues.
Innovation Solution
A plain bearing with a hollow cylindrical body and annular core featuring regularly distributed lightening holes to reduce mass, improving flexibility and lubrication efficiency by preventing hot oil from heating cold oil.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If plain bearings are made substantial to ensure sufficient rigidity and damping capacity, then mechanical strength and vibration damping are improved, but mass increases leading to unbalance, high vibrations, and radial forces
Solution Approach 1:
The plain bearing is segmented into a hollow cylindrical structure with an annular core, creating multiple chambers (front annular space, rear annular space, and internal cavity) that reduce mass while maintaining structural integrity and damping capacity through distributed oil film formation
Solution Approach 2:
The bearing incorporates oil passage orifices and relief holes that create a porous-like structure, allowing oil to penetrate and form lubricating films in multiple zones, reducing mass while maintaining lubrication and damping functions
2Strength
If plain bearings have substantial mass to maintain structural integrity, then mechanical strength is improved, but friction losses increase and heat dissipation becomes inefficient
Solution Approach 1:
The bearing is divided into multiple lubrication zones (front annular space, rear annular space, internal cavity) separated by the annular core, allowing independent oil circulation and heat dissipation in each zone, reducing friction losses and improving thermal management
Solution Approach 2:
The bearing utilizes hydraulic principles by forming oil films in multiple chambers and using relief holes to regulate oil pressure and flow, enabling efficient lubrication and heat dissipation that reduces friction energy losses
3Ease of operation
If plain bearings orbit around the solar array's axis, then satellite guidance function is achieved, but unbalance and high-amplitude vibrations occur
Solution Approach 1:
The bearing's porous-like structure with relief holes and multiple oil passages allows oil to penetrate throughout the bearing structure, creating distributed damping zones that reduce vibrations and unbalance forces generated during orbital motion
Solution Approach 2:
The bearing design changes the oil distribution parameters by introducing multiple lubrication zones and relief holes, optimizing oil film thickness and pressure distribution to minimize vibrations and unbalance during satellite guidance operation
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 reduces the mass of the plain bearing, minimizing vibrations and misalignments, enhancing lubrication efficiency by effectively dissipating heat and reducing friction losses.
Implementation Method 1
each satellite is mounted for rotation on and around a plain bearing, which is supplied with oil and configured to form an oil film between the outer periphery of the bearing and the inner periphery of the satellite
Implementation Method 2
an annular core extending around the axis, between the body and the wall... delimits around the body an annular space in front of the core and an annular space behind the core
Data Source
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AI summary
Plain bearing (110) for a satellite of a mechanical reducer (6) of a turbomachine (1), in particular of an aircraft, this plain bearing (110) being formed of a single piece and comprising: - a hollow cylindrical body (20b) which includes an axis (Y) and which internally defines a cavity (10c) intended to receive oil, - an annular wall (20a) which extends around the axis (Y) and the hollow body (20b) and which includes an external cylindrical guiding surface (25a), - an annular web (20c) which extends around the axis (Y), between the body (20b) and the wall (20a), where it includes at least one annular row of lightening holes (122) in said web (20c), these holes (122) being regularly distributed all around the axis (Y).