Rotating Arm Locking Spacer for Gas Turbine Rotor Blades
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Solution Overview
Problem
The existing locking spacers for rotor blades in gas turbines are difficult to assemble and disassemble, particularly the last spacer which cannot be rotated into the dovetail slot, requiring a specific structure that is simple, robust, and easy to maintain.
Innovation Solution
A locking spacer design comprising a pair of first blocks with dovetail joints, a pair of second blocks with locking grooves, and a locking block with a rotating locking arm, allowing assembly in a radial direction without rotation, facilitated by guide protrusions and grooves, and a hexagon socket rotating rod for easy engagement and disengagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional locking spacer is designed to fit tightly in the dovetail slot without rotation, then secure engagement is achieved, but assembly and disassembly become difficult
Solution Approach 1:
The locking spacer is divided into multiple blocks (first blocks with dovetail joints, second blocks with locking grooves, and a locking block with rotating locking arm). This segmentation allows the spacer to be assembled by inserting blocks sequentially in the radial direction without rotation, while the locking arm provides secure engagement. The segmented structure resolves the contradiction by enabling easy assembly through radial insertion while maintaining reliable locking through the rotating arm mechanism.
Solution Approach 2:
The locking arm is designed to be rotatable within the locking block, providing a dynamic element that enables easy engagement and disassembly. When the locking arm rotates to engage with the locking grooves, secure engagement is achieved; when it rotates back, disassembly becomes simple. This dynamic feature resolves the contradiction between secure engagement and ease of operation.
2Adaptability or versatility
If the locking spacer requires rotation for assembly like other blades and spacers, then consistent assembly procedure is maintained, but the last spacer cannot be properly engaged
Solution Approach 1:
Instead of requiring rotation for assembly like conventional blades and spacers, the locking spacer is designed to be inserted in the opposite manner - directly in the radial direction without rotation. The dovetail joints of the first blocks engage with the dovetail surfaces axially, and subsequent blocks are inserted radially. This inverted assembly approach resolves the contradiction by allowing proper engagement of the last spacer while maintaining overall assembly procedure consistency through the use of guide protrusions and grooves.
Solution Approach 2:
Guide protrusions and grooves act as intermediaries that facilitate the non-rotational assembly of the locking spacer. These guide features ensure proper alignment and positioning of the blocks during radial insertion, enabling the locking spacer to be assembled correctly without rotation. The intermediary guide structures resolve the contradiction by mediating between the need for consistent assembly procedures and the requirement for proper engagement capability.
3Ease of repair
If a complex locking mechanism is designed to enable easy disassembly, then maintenance becomes simple, but device complexity increases
Solution Approach 1:
The locking mechanism is segmented into distinct functional blocks: first blocks with dovetail joints for axial engagement, second blocks with locking grooves for lateral positioning, and a locking block with a rotating locking arm for secure locking. This segmentation maintains relative simplicity while enabling easy maintenance, as each block can be independently manufactured and replaced if needed.
Solution Approach 2:
The rotating locking arm provides a self-service locking mechanism that requires minimal external intervention for maintenance. The locking arm can be manually rotated to engage or disengage the locking grooves, allowing operators to perform maintenance without specialized tools or complex procedures. This self-service feature resolves the contradiction by providing simple maintenance access while keeping the overall device complexity manageable.
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
Enables easy assembly and disassembly of the locking spacer, ensuring secure engagement without rotation, facilitating manufacturing and maintenance, and resisting centrifugal forces during rotor operation.
Implementation Method 1
resisting centrifugal forces during rotor operation
Data Source
AI summary
A locking spacer, which is fitted in a dovetail slot provided on an outer circumferential surface of a disk put on a rotor shaft, includes: a pair of first blocks each provided with a dovetail joint, and configured to have a size occupying a portion of an internal space of the dovetail slot; a pair of second blocks having a size occupying a portion of the internal space of the dovetail slot, the portion not being occupied by the pair of first blocks, and each being provided with a locking groove; and a locking block having a size occupying a portion of the internal space of the dovetail slot, the portion not being occupied by the first and second blocks, and being provided with a rotating locking arm configured such that opposite end portions thereof are inserted into the locking grooves.