Segmented Rotor Disk Fastening with Anti-Rotation Flange
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Solution Overview
Problem
The compactness of rotor components in gas turbine engines poses challenges in assembling rotor disks to a shaft due to the need for sufficient clearance for elongated bolts, which compromises the compactness of the rotor.
Innovation Solution
A rotor disk assembly with circumferentially distributed throughbores and connector bolts featuring an anti-rotation flange, allowing secure fastening without requiring high preloads and enabling axial movement of rotor disks for efficient interconnection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If elongated bolts are used to interconnect rotor disks with sufficient clearance, then the rotor disks can be securely fastened, but the compactness of the rotor is compromised
Solution Approach 1:
The bolt is segmented into two distinct parts: a reusable connector bolt with flange that remains attached to the first rotor disk, and a removable head that is installed on the second rotor disk. This segmentation allows the bolt function to be divided between two components, enabling compact assembly while maintaining secure fastening.
Solution Approach 2:
Instead of the traditional bolt configuration where the head is on one end and threads are on the other, this invention inverts the structure by placing a flange in the middle with threads on both sides. The flange acts as the permanent attachment point, while the removable head serves as the fastening element, reversing the conventional bolt design approach.
2Ease of manufacture
If sufficient clearance is provided for bolt installation, then rotor disks can be assembled, but the overall rotor length increases
Solution Approach 1:
The connector bolt is pre-assembled with the first rotor disk before the final assembly process. The flange is permanently attached to the first rotor disk, and the removable head is pre-positioned on the second rotor disk. This preliminary preparation eliminates the need for complex alignment and installation clearance during final assembly, reducing the overall rotor length.
3Device complexity
If connector bolts are used without anti-rotation features, then the assembly process is simpler, but the connector bolts may rotate when the removable head is installed
Solution Approach 1:
The flange is designed with asymmetric features including a non-circular shape with flat surfaces that mate with corresponding features on the rotor disk. This asymmetric geometry prevents rotation of the connector bolt while maintaining a relatively simple overall structure, balancing complexity and reliability.
Data Source
AI summary
A rotor disk assembly comprises a first rotor disk with a plurality of circumferentially distributed first throughbores. A second rotor disk comprises a connection portion projecting at least partially axially, a plurality of circumferentially distributed second throughbores being provided in the connection portion in cooperative distribution relative to the first rotor disk for the first and second throughbores to be in register with one another in the rotor disk assembly. Connector bolts each have an elongated body with a flange between its ends, a head at its first end and a removable head at its second end, the head at the first end spaced apart from the flange for the connector bolt to be secured to one of the rotor disks at a respective throughbore, the removable head at the second end being spaced apart from the flange for the second end to project. An anti-rotation feature is between each said connector bolt and at least one of the rotor disks to prevent rotation of the connector bolts when the removable head is installed on the second end in the rotor disk assembly.