Split Sun Gearbox Assembly With Single-Piece Ring Gear
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Solution Overview
Problem
Existing gearbox assemblies for turbine engines face challenges in achieving a compact design with low weight, high performance, and efficient fuel burn, often due to the use of split ring gears that result in increased radial envelope and potential fretting issues.
Innovation Solution
A gearbox assembly featuring a split sun gear and a single piece ring gear, utilizing double helical gears with opposing helix angles, which eliminates bolted connections and minimizes radial deflection, allowing for a lower radial envelope and enhanced efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If split ring gears are used, then assembly flexibility is improved, but radial envelope increases and fretting issues occur
Solution Approach 1:
The sun gear is divided into two separate pieces (forward sun gear and aft sun gear) that can be assembled independently onto the input shaft. This segmentation allows for easier assembly while maintaining a compact radial envelope, as each piece can be installed separately without requiring the entire ring gear to be split.
Solution Approach 2:
Instead of splitting the ring gear as in conventional designs, the invention inverts the approach by splitting the sun gear. This reversal of the segmentation location eliminates the need for bolted connections in the ring gear, reducing radial envelope and preventing fretting issues while preserving assembly flexibility.
2Ease of manufacture
If bolted connections are used in ring gear, then assembly is simplified, but radial deflection increases and fretting occurs
Solution Approach 1:
The invention reverses the conventional approach by applying segmentation to the sun gear rather than the ring gear. This eliminates bolted connections from the ring gear entirely, preventing fretting and radial deflection while maintaining assembly simplicity through the segmented sun gear design that can be installed piece by piece.
3Weight of moving object
If compact design is achieved, then weight is reduced, but manufacturing complexity increases
Solution Approach 1:
The sun gear is segmented into two pieces that can be manufactured separately using standard manufacturing processes, then assembled onto the input shaft. This segmentation enables a compact gearbox design with reduced weight while avoiding excessive manufacturing complexity, as each piece can be produced with conventional methods.
Solution Approach 2:
The invention changes the configuration parameter from a single-piece sun gear to a two-piece sun gear, and from a split ring gear to a single-piece ring gear. These parameter changes optimize the weight-to-manufacturing-complexity ratio by enabling compact design through sun gear segmentation while simplifying ring gear manufacturing.
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
A turbine engine (10) having a turbo-engine (16) coupled to an input shaft (210, 210', 510, 510', 710, 810), a fan (42) coupled to an output shaft (214), and a gearbox assembly (52, 200). A torque is transferrable from the input shaft (210, 210', 510, 510', 710, 810) to the output shaft (214) through the gearbox assembly (52, 200). The gearbox assembly (52, 200) has a split sun gear rotationally coupled to the input shaft (210, 210', 510, 510', 710, 810), a plurality of planet gears (204) located radially outward of, and intermeshing with, the split sun gear, and a single piece ring gear (206) located radially outward of, and intermeshing with, the plurality of planet gears (204). The split sun gear comprising a forward sun gear (216, 416, 516, 516', 716, 816) and an aft sun gear (218, 418, 518, 518', 718, 818) separate from the forward sun gear (216, 416, 516, 516', 716, 816), wherein the forward sun gear (216, 416, 516, 516', 716, 816) and the aft sun gear (218, 418, 518, 518', 718, 818) are each rotationally coupled to the input shaft (210, 210', 510, 510', 710, 810).