Oil Pump Bore Lip Structure for Rotorcraft Gearbox Containment
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Solution Overview
Problem
Existing rotorcraft gearbox oil pump systems are vulnerable to catastrophic failure due to high lubricant pressures at varying temperatures, which can cause the oil pump components to fall into the gearbox, leading to potential system failure.
Innovation Solution
The oil pump receiving bore in the rotorcraft gearbox features a radially extending lip that reduces the diameter of the opening, acting as a failsafe to prevent the oil pump and cover from entering the gearbox in case of a failure, ensuring the components remain contained.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the oil pump opening diameter is large enough to allow easy installation, then the ease of operation improves, but the risk of pump components falling into the gearbox increases under high pressure
Solution Approach 1:
The opening is segmented into two distinct openings: a first opening with a larger diameter for easy installation of the oil pump, and a second opening with a smaller diameter that prevents pump components from falling into the gearbox. This segmentation allows each opening to serve its specific function optimally.
Solution Approach 2:
A lip structure is introduced as an intermediary element between the two openings. The lip extends radially inward from the first opening and defines the smaller second opening, acting as a physical barrier that prevents pump components from passing through while maintaining the larger installation opening.
2Reliability
If the opening diameter is reduced to prevent component failure, then the reliability improves, but the ease of installing the oil pump deteriorates
Solution Approach 1:
The opening is segmented into two distinct openings: a first opening with a larger diameter for easy installation of the oil pump, and a second opening with a smaller diameter that prevents pump components from falling into the gearbox. This segmentation allows each opening to serve its specific function optimally.
Solution Approach 2:
The solution moves from a single-dimensional opening size constraint to a two-dimensional approach by creating an annular structure with the lip extending radially inward. This dimensional change allows the opening to simultaneously provide large access area for installation and small effective diameter for safety containment.
3Device complexity
If the oil pump receiving bore design is simplified, then the device complexity reduces, but the ability to prevent catastrophic failure under varying temperature and pressure conditions deteriorates
Solution Approach 1:
The lip structure is merged with the oil pump receiving bore as an integral feature rather than a separate component. The lip is formed as part of the bore structure itself, combining the containment function with the existing receiving bore design, thereby preventing catastrophic failure without significantly increasing device complexity.
Data Source
AI summary
A gearbox system for a rotorcraft includes a gearbox housing, an oil pump receiving bore formed into the gearbox housing and having formed therein a first opening having a first diameter and a second opening, and an oil pump positioned within the oil pump receiving bore. The second opening is bounded by a lip that extends radially into the second opening, the second opening having a second diameter that is smaller than the first diameter.