Planetary Gearbox Pin Attachment Using Centrifugal Centering Collars
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing gas turbine engines face challenges in securely attaching planetary pins to support plates under high radial forces without the need for strong press fits, which complicates manufacturing and increases the risk of component damage during assembly and disassembly.
Innovation Solution
The use of a form-fit mechanism between first and second centering collars, where the second centering collar is connected to the planetary pin and engages radially outside the first centering collar, enhances the pressing force through centrifugal forces, allowing for a lighter press fit and reducing deformation, thus eliminating the need for elaborate press fitting tools.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a strong press fit is used to attach the planetary pin to the support plate, then the connection reliability under high radial forces is improved, but the manufacturing complexity and risk of component damage increase
Solution Approach 1:
The attachment system is segmented into multiple functional elements: the support plate with opening, the planetary pin, and two centering collars (first centering collar on the support plate, second centering collar on the planetary pin). This segmentation allows each component to have a specific function - the centering collars handle the form-fit connection and centrifugal force management, while the planetary pin focuses on torque transmission, thereby reducing the complexity of the press fit operation.
Solution Approach 2:
The centering collars act as intermediary elements between the planetary pin and the support plate. Instead of directly pressing the planetary pin into the support plate opening, the centering collars mediate the connection by engaging with each other radially outside. This intermediary mechanism transforms the attachment process, allowing centrifugal forces to reinforce rather than undermine the connection, thus reducing the need for elaborate press fitting tools.
2Stability of the object's composition
If a strong press fit is used to prevent loosening under centrifugal forces, then the connection stability is improved, but the risk of component damage during assembly increases
Solution Approach 1:
The invention converts the harmful centrifugal forces that tend to loosen the connection into a beneficial reinforcement mechanism. The centering collars are positioned such that centrifugal forces act radially outside on the second centering collar, which in turn presses radially inside against the first centering collar. This transforms the previously harmful centrifugal effect into a force that strengthens the connection, eliminating the need for excessively strong press fits that could damage components.
Solution Approach 2:
The traditional approach presses the planetary pin radially inside into the support plate opening. The invention inverts this approach by having the centering collars engage radially outside, where centrifugal forces act most strongly. This inversion allows the centrifugal forces to work in favor of the connection rather than against it, reducing assembly complexity and damage risk.
3Reliability
If a strong press fit is used to prevent oil leakage, then the sealing reliability is improved, but the manufacturing effort and component damage risk increase
Solution Approach 1:
The centering collars create a sealing interface that benefits from centrifugal forces. As the planetary gearbox operates, centrifugal forces press the second centering collar against the first centering collar radially inside, enhancing the sealing effect. This eliminates the need for extremely tight press fits that would be required to prevent oil leakage under centrifugal forces, thereby reducing manufacturing effort and the risk of damaging the planetary pin or support plate during assembly.
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
This solution simplifies the mounting and dismantling of planetary gearboxes, reduces the risk of component damage, and maintains a secure connection between the planetary pin and support plates under operational conditions, preventing loosening and oil leakage.
Implementation Method 1
Through a centrifugal force, a radially outward force acts on the planetary pin and thus on the second centering collar in the radially outer area of the planetary pin. In this way, the second centering collar is pressed in a stronger manner against the first centering collar in the radially inner area of the planetary pin, whereby the pressing force between the first centering collar and the second centering collar is increased.
Data Source
AI summary
A gas turbine engine for an aircraft that includes an engine core, a fan, and a planetary gearbox. The planetary gearbox includes a sun gear, a plurality of planetary gears, a ring gear, a plurality of planetary pins, wherein respectively one planetary pin is arranged in a planetary gear, and an axially frontal support plate and an axially rear support plate, wherein the planetary pins are arranged in openings of the axially frontal support plate and of the axially rear support plate, and are connected to the support plates. At least one of the support plates has an axially protruding first centering collar that engages around the opening for the planetary pin, and that a second centering collar that is connected to the planetary pin or is formed in one piece with the same, engaging around the first centering collar radially outside in a form-fit manner. A planetary gearbox and an attachment arrangement.