Epicyclic Ring Gear Tooth Alignment via Positioning Pin
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Solution Overview
Problem
The challenge lies in aligning the teeth of two half-ring gears in an epicyclic reduction gear, which are manufactured in two parts to ensure zero radial clearance and interference fit, while accounting for potential tooth offset during assembly, without compromising precision or increasing costs in a serial production context.
Innovation Solution
The solution involves using an angular positioning pin and multidimensional coordinate measurement to align the teeth, where one hole is drilled smaller than the final cross-section on one half-ring gear, allowing for precise re-drilling based on positional deviations, and a shrink fit assembly to secure the alignment and prevent axial misalignment, with additional steps for accurate measurement and averaging to ensure quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the ring gear is made in two half-ring gears for manufacturing reasons, then the ease of manufacture is improved, but the alignment precision of teeth between the two half-ring gears deteriorates
Solution Approach 1:
A positioning pin is introduced as an intermediary element to ensure precise angular alignment between the two half-ring gears during assembly. The positioning pin fits into corresponding positioning holes drilled in each half-ring gear, serving as a mediator that transfers and maintains the correct angular relationship between the two parts, thereby resolving the alignment precision issue while preserving the manufacturing benefits of divided construction
Solution Approach 2:
Positioning holes are drilled in advance during the manufacturing process of each half-ring gear, before assembly. This preliminary action ensures that when the half-ring gears are assembled, the positioning pin can be directly inserted into pre-drilled holes that are already precisely located, eliminating the need for complex alignment operations during assembly and ensuring high alignment precision
2Reliability
If an interference fit is used to ensure zero radial clearance between half-ring gears, then the reliability is improved, but the difficulty of assembly increases due to tooth offset issues
Solution Approach 1:
The positioning pin acts as a mediator that simplifies the assembly process by providing a straightforward mechanical guide for aligning the teeth of the two half-ring gears. Instead of relying solely on complex interference fit procedures that require precise tooth-to-tooth alignment, the positioning pin provides a simple insertional action that automatically establishes the correct angular relationship, thereby reducing assembly complexity while maintaining the reliability benefits of zero radial clearance through interference fit
3Manufacturing precision
If multidimensional coordinate measurement and re-drilling is performed to correct positional deviations, then the manufacturing precision is improved, but the loss of time in serial production increases
Solution Approach 1:
Positioning holes are drilled in advance during the manufacturing process with initial tolerances that are easier to achieve than final precision requirements. This preliminary drilling action allows for subsequent precise re-drilling or positioning operations to be performed on pre-positioned workpieces, thereby improving final positional accuracy without significantly increasing total production time, as the time-consuming precise positioning is done once during manufacturing rather than repeatedly during assembly
Solution Approach 2:
The positioning system is designed to be self-aligning through the positioning pin and holes, which automatically establish the correct angular relationship between half-ring gears during assembly. This self-service mechanism eliminates the need for complex measurement and adjustment operations during assembly, reducing assembly time while maintaining high precision through the self-aligning nature of the pin-hole interface
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 method ensures precise alignment and assembly of the half-ring gears, maintaining zero radial clearance and optimizing the performance of the epicyclic reduction gear by minimizing precision loss and enabling efficient angular resetting, thus addressing the issue of tooth offset and misalignment effectively.
Implementation Method 1
ensure a zero radial clearance between the two half-ring gears in question, which imposes a interference fit between them
Implementation Method 2
the assembly step of the first and second half-ring gears comprises a shrink fit assembly
Data Source
AI summary
A method for aligning toothing in an assembly of two half-ring gears is provided:an angular positioning pin is provided which is to be received in respective holes of the half-ring gears;the holes are drilled on the first half-ring gear such that the first hole has a first cross-section that is smaller than the final cross-section thereof;the angles between the teeth are compared between the two half-ring gears, and an angular difference between said angles of the half-ring gears is deduced therefrom;the first hole is redrilled to the final cross-section, while the centre of the hole is angularly shifted by the value of the angular difference;the pin is engaged in the holes, and the half-ring gears are then assembled using an interference fit.