Crowned Spline Coupling for Turbine Gearbox Misalignment
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Solution Overview
Problem
There is a need for structures and components that facilitate the arrangement of electric machines within the core of a gas turbine engine, particularly for coupling rotating components like the electric machine or gearbox with the turbine engine shaft, to reduce the overall size of the engine.
Innovation Solution
The use of a crowned spline connection for coupling the turbine engine shaft and gearbox, allowing for flexible alignment and movement, with a splined shaft and element configuration that includes a base, rim, and retainers, and a seal land for axial fixation and sealing, enabling the integration of the electric machine within the engine core.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the electric machine is arranged within the engine core, then the overall size of the gas turbine engine is reduced, but the coupling between rotating components becomes more complex and difficult to implement
Solution Approach 1:
The coupler is divided into multiple segments including a shaft portion, a gear portion, and a splined element portion. This segmentation allows each part to be optimized independently for its specific function while simplifying the overall coupling mechanism between the electric machine and turbine engine shaft
Solution Approach 2:
The crowned spline connection uses curved crown surfaces instead of straight splines. This curvature allows the splined element to accommodate misalignment and pivot relative to the shaft and gear, simplifying the coupling mechanism by eliminating the need for complex alignment systems
2Power
If a rigid spline connection is used to couple the shaft and gear, then mechanical power transmission is efficient, but the coupling cannot accommodate operational shifts and misalignment
Solution Approach 1:
The rigid spline connection is transformed into a dynamic crowned spline connection where the splined element can pivot and shift relative to the shaft and gear. This dynamic capability allows the coupling to maintain efficient power transmission while adapting to operational misalignment and shifts
Solution Approach 2:
The spline geometry is changed from straight to crowned (curved) surfaces. This parameter change in the spline profile allows the connection to accommodate angular misalignment while maintaining the necessary mechanical power transmission capability
3Power
If the splined element is fixed rigidly to the shaft, then power transmission is direct, but the coupling cannot pivot to accommodate misalignment
Solution Approach 1:
The coupling is segmented into a shaft portion, a splined element portion, and a gear portion that are connected through crowned spline interfaces. This segmentation allows the splined element to pivot relative to the shaft while maintaining direct power transmission, and then connect to the gear with proper alignment
Data Source
AI summary
An assembly is provided for a turbine engine. This turbine engine assembly includes a turbine engine shaft, a gearbox and a coupler. The turbine engine shaft is configured to rotate about a rotational axis. The gearbox includes a gear configured to rotate about the rotational axis. The coupler is coupled to the turbine engine shaft by a coupler-shaft connection. The coupler-shaft connection is configured as or otherwise includes a crowned spline connection. The coupler is coupled to the gear by a coupler-gear connection. The coupler-gear connection is configured as or otherwise includes a crowned spline connection.