Turbine Rotor Weight Entry Port With Rounded Crack-Resistant Geometry
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Solution Overview
Problem
The existing method of forming balancing weight entry ports in turbine rotors through milling can result in damage such as cracking due to the creation of peaks and sharp corners, which are difficult to repair without further damaging the rotor.
Innovation Solution
A tool and method using motorized machining with a clamp system and radial positioning to create a balancing weight entry port with rounded corners, extending farther into the rotor body than the slot, to prevent damage and facilitate the introduction of balancing weights while avoiding sharp edges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If milling is used to form the balancing weight entry port, then the port can be created to allow weight introduction, but peaks and sharp corners are left that initiate cracking damage
Solution Approach 1:
The patent applies curvature by replacing the sharp corners and peaks created by conventional milling with rounded surfaces. The entry port is formed with curved transitions instead of abrupt angular features, eliminating stress concentration points that would initiate cracking. This spherical/curved geometry modification directly addresses the reliability issue while maintaining manufacturability.
2Ease of operation
If the entry port extends beyond the slot to facilitate weight introduction, then weight installation is easier, but damage repair becomes more difficult
Solution Approach 1:
By forming the entry port with rounded corners and smooth curved surfaces rather than sharp edges and peaks, the patent eliminates stress concentration zones. This curved geometry prevents crack initiation at the port boundaries, making the structure more resistant to damage and easier to repair if damage occurs, while still providing adequate access for weight installation.
3Ease of operation
If retaining members are removed to create the entry port, then weights can be introduced circumferentially, but sharp corners remain at the bottom of sidewalls
Solution Approach 1:
The patent directly addresses the harmful sharp corners by replacing them with rounded curved surfaces at the bottom of the entry port sidewalls. This curvature modification eliminates the stress concentration points that would otherwise initiate cracking, while preserving the functional ability to introduce weights circumferentially through the entry port.
Data Source
AI summary
A turbine rotor includes a rotor body and a balancing weight slot defined in an exterior circumference of the body. The balancing weight slot has a first axial width and a first radially outward facing surface at a first radial distance from a rotor axis. The rotor also includes a balancing weight entry port defined in a portion of the exterior circumference of the rotor body, aligned with the balancing weight slot. The balancing weight entry port has a second axial width greater than the first axial width and a second radially outward facing surface at a second radial distance from the axis of the rotor body smaller than the first radial distance. A method may include machining the entry port into the rotor with a tool. The method may be applied to a new rotor, or to remove cracks initiating from a previous entry port.