Radial Pin Securing Device for Steam Turbines
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Solution Overview
Problem
The existing securing devices for rotary machines, such as steam turbines, face challenges in preventing radial pins from moving outward due to the need for larger fastening members, which complicates the structure and makes it difficult to minimize the size of components that restrain radial pin movement.
Innovation Solution
A securing device with a radial pin and a pin support unit, where the radial pin has a flange portion and is inserted into a through-hole with a smaller inner diameter, and the pin support unit overlaps the radial pin, using a support sleeve and spacer to prevent movement, thereby simplifying the structure and maintaining the relative position of the outside and inside members.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a lid is provided on the outside of the radial pin and secured to the casing using bolts, then the radial pin is restrained from moving toward the outside in the radial direction, but the size of the fastening member such as a bolt must be increased and the size of the lid must be increased
Solution Approach 1:
The pin support unit is inserted into the outside hole of the outside member, nesting the support structure within the existing hole rather than adding an external lid. This eliminates the need for a separate lid component and reduces overall structure size while maintaining the restraint function.
Solution Approach 2:
The restraint function is extracted from a separate lid component and integrated directly into the pin support unit that is inserted into the outside hole. This consolidation removes the need for additional fastening members like bolts and reduces the number of components required.
2Reliability
If a lid is provided on the outside of the radial pin and secured to the casing using bolts, then the radial pin is restrained from moving toward the outside in the radial direction, but the number of components increases
Solution Approach 1:
The pin support unit combines multiple functions into a single component: it supports the radial pin, prevents outward movement, and integrates with the outside member through the outside hole. This merging eliminates the need for separate lid and bolt components, reducing the total number of parts.
Solution Approach 2:
The restraint function is extracted from a multi-component lid assembly and implemented through the pin support unit inserted into the outside hole. This extraction simplifies the component structure by eliminating unnecessary separate parts while maintaining the essential restraint capability.
3Reliability
If the size of the lid is increased to restrain the radial pin, then the radial pin movement is prevented, but the overall device size increases
Solution Approach 1:
The pin support unit is nested within the outside hole of the outside member, utilizing the existing space rather than adding external volume. This nesting approach prevents radial pin movement without increasing the overall device envelope, maintaining a compact design.
Solution Approach 2:
Instead of increasing the radial size of a lid to restrain the pin, the solution transitions to a different dimensional approach by inserting the pin support unit axially into the outside hole. This dimensional change allows effective restraint without increasing the radial or overall device dimensions.
Data Source
AI summary
A securing device having a radial pin which is inserted into a through-hole having an outside hole and an inside hole and penetrating an outside member in the radial direction of a rotary machine, the outside hole being open to the outside of the outside member in the radial direction of the rotary machine, the inside hole communicating with the outside hole, having a smaller diameter than the outside hole, and being open to the inside in the radial direction of the rotary machine, the radial pin having a portion on the inside in the radial direction of the rotary machine inserted into a recess formed in an inside member, and including a flange portion having an outer diameter larger than a diameter of the inside hole; and a pin support unit which is inserted into the outside hole on the outside in the radial direction of the rotary machine.