Turbine Rotor Weight Entry Port With Rounded Anti-Crack Machining
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Solution Overview
Problem
The existing methods for creating balancing weight entry ports in turbine rotors often result in damaging peaks and sharp corners, which can lead to cracking and are difficult to repair without causing further damage.
Innovation Solution
A tool and method using motorized machining with a clamp system and positioning systems to create a balancing weight entry port with rounded corners, extending farther into the rotor body than the slot, to prevent cracking and facilitate easier repair.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional milling is used to create the balancing weight entry port, then the port can be formed to allow weight introduction, but peaks and sharp corners are created that lead to cracking and damage
Solution Approach 1:
The invention applies curvature by forming rounded corners and peaks at the bottom of the entry port sidewalls instead of sharp angles. The machining process creates radiused transitions that eliminate stress concentration points, directly preventing crack initiation while maintaining the port's functionality for weight introduction.
Solution Approach 2:
The invention applies different surface qualities to different locations within the entry port. The bottom corners and peaks are specifically modified with rounded geometries, while other portions of the port maintain their original milling characteristics. This localized quality change addresses the cracking problem at critical stress points without unnecessarily altering the entire port structure.
2Ease of operation
If the entry port is milled to larger axial extent than the slot, then weights can be introduced circumferentially, but retaining members are removed and damage risk increases
Solution Approach 1:
The rounded corners and peaks created by the machining process eliminate sharp stress concentration points at the bottom of the entry port. This curvature modification allows the port to extend axially beyond the slot for easy weight introduction while preventing crack initiation that would compromise rotor integrity.
Solution Approach 2:
The invention preemptively removes material to create rounded, radiused transitions at the bottom corners and peaks of the entry port before operation begins. This prior cushioning of stress concentrations prevents crack initiation during subsequent weight introduction and rotor operation, maintaining reliability while enabling ease of operation.
3Ease of manufacture
If sharp corners and peaks remain in the entry port, then manufacturing is simpler, but repair of damage is very difficult
Solution Approach 1:
The rounded corners and peaks created by the machining process eliminate sharp stress concentration points that would initiate cracks. This curvature modification maintains manufacturing simplicity while dramatically improving repairability, as damage can be removed and the rounded geometry restored without compromising structural integrity.
Data Source
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AI summary
A turbine rotor (110) includes a rotor body (112); and a balancing weight slot (122) defined in an exterior circumference (244) of the body. The balancing weight slot (122) has a first axial width and a first radially outward facing surface (232) at a first radial distance from an axis of the rotor. The rotor also includes a balancing weight entry port (142) defined in a portion of the exterior circumference (244) of the rotor body (112) and aligned with the balancing weight slot (122). The balancing weight entry port (142) has a second axial width greater than the first axial width and a second radially outward facing surface (232) at a second radial distance from the axis of the rotor body (112) that is 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 a used rotor to remove cracks initiating from a previous entry port.