Aircraft Turbine Gear Reducer With Sun Gear Radial Centering
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Solution Overview
Problem
Mechanical reduction gears in turbomachines, particularly in aircraft turbomachines, face misalignment issues due to the lack of radial centering, leading to significant restoring forces and overloads on teeth, which existing technologies fail to adequately address.
Innovation Solution
Incorporating at least one second bearing for guiding the rotation of the solar, in addition to the existing satellite carrier bearings, allows for radial centering of the solar, preventing misalignment and overloads by providing additional support and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If axial stops are provided to limit axial displacement of the sun gear, then axial positioning is improved, but radial centering is not ensured and the sun gear remains misaligned in the radial direction
Solution Approach 1:
The patent introduces a second bearing as an intermediary component between the sun gear and planet carrier to provide radial centering. This bearing acts as a mediator that specifically addresses the radial positioning issue without interfering with the axial positioning already provided by the axial stops.
Solution Approach 2:
The patent segments the positioning function into two independent components: axial stops for axial positioning and a second bearing for radial centering. This segmentation allows each component to specialize in one dimension of positioning, resolving the contradiction by ensuring both axial stability and radial precision are addressed separately and effectively.
2Ease of manufacture
If the solar unit is left axially free to rotate, then ease of assembly is improved, but the pinions can rub in contact with other components causing wear and misalignment
Solution Approach 1:
The patent applies preliminary anti-action by providing axial stops that prevent the sun gear from displacing axially before operational loads can cause misalignment. This preventive measure counteracts the potential harmful effect of axial freedom, allowing easy assembly while ensuring operational reliability by preventing contact between pinions and other components.
3Power
If helical teeth are used in the sun gear, then meshing performance is improved, but significant axial forces are generated that stress the pinions in the axial direction
Solution Approach 1:
The second bearing acts as an intermediary that supports and distributes the axial forces generated by helical teeth. By providing a dedicated radial support mechanism, the bearing mediates the stress on pinions, allowing the use of high-power helical gearing while protecting the pinions from excessive axial stress.
Data Source
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AI summary
Mechanical reducer (6) for a turbomachine (1), in particular for aircraft, this reducer comprising: - a sun gear (7) having internal splines (7a) and external teeth (7b), - a ring gear (9) which extends around the sun gear (7) and which includes internal teeth, - satellites (8) which are arranged between the sun gear and the ring gear and which each include at least one external teeth (8d) for meshing with said external teeth of the sun gear and said internal teeth of the ring gear, and - a satellite carrier (10) which carries first bearings (11) for guiding the rotation of the satellites, characterized in that it further comprises at least one second bearing (200, 201) for guiding the rotation of the sun gear (7), said at least one second bearing (200, 201) being mounted between the sun gear (7) and the satellite carrier (10).