Vacuum Circuit Breaker Withdrawable Device Load Distribution
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Solution Overview
Problem
Conventional withdrawable devices for vacuum circuit breakers have a complex structure with many components, leading to reduced reliability due to axial loads and friction, causing instability and potential damage during operation at run and test positions.
Innovation Solution
A simplified withdrawable device with a ring-shaped guide recess on the transfer nut and symmetric supporting surfaces for rotation prevention pins, reducing axial loads to distributed loads and minimizing component damage, and enhancing idle operation reliability by attenuating axial forces through a thrust bearing and buffer members.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional withdrawable device with multiple components (transfer nut, guiding recesses, rotation prevention pins, connection plates, driving pins) is used, then the structure can achieve carrier movement and idle operation, but the structure becomes complex and reliability decreases due to axial loads and friction
Solution Approach 1:
The patent combines multiple separate components (transfer nut, guiding recesses, rotation prevention pins, connection plates, driving pins) into a simplified integrated structure. The transfer nut is directly coupled to the carrier with guiding recesses formed on its outer circumferential surface, eliminating the need for separate guiding components and rotation prevention mechanisms, thereby reducing structural complexity while maintaining operational reliability
Solution Approach 2:
The transfer nut is designed to perform multiple functions simultaneously: it transmits rotational motion from the lead screw to the carrier for movement, provides guiding functionality through its circumferential guiding recesses, and prevents rotation through the symmetric supporting surfaces. This multi-functionality reduces the number of separate components needed, simplifying the overall structure
2Ease of repair
If multiple components (rotation prevention pins, driving pins, connection plates) are used to prevent transfer nut rotation, then rotation can be controlled, but the number of components increases and maintenance difficulty increases
Solution Approach 1:
The rotation prevention functionality is integrated directly into the transfer nut structure through symmetric supporting surfaces formed on its sidewalls, eliminating the need for separate rotation prevention pins, driving pins, and connection plates. This integration significantly reduces the number of components and simplifies maintenance procedures
Solution Approach 2:
The transfer nut's symmetric supporting surfaces automatically prevent rotation during operation without requiring additional active components. The structure self-regulates rotation prevention through its geometric design, reducing the need for separate control mechanisms and simplifying maintenance
3Strength
If axial loads are applied to the transfer nut during carrier movement, then the carrier can be moved along the lead screw, but the axial loads cause friction and potential damage to components
Solution Approach 1:
The patent incorporates buffer members that provide cushioning support to the transfer nut before axial loads can cause damage. These buffer members absorb and distribute the axial loads during carrier movement, preventing direct transmission of harmful forces to the transfer nut and associated components, thereby enhancing durability
Solution Approach 2:
The symmetric supporting surfaces on the transfer nut change the load distribution parameters by providing balanced support in opposite directions. This geometric parameter change distributes axial loads more evenly across the transfer nut structure, reducing stress concentration and potential damage
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
The solution simplifies the structure, reduces component wear, and improves operational reliability by converting axial loads into distributed loads, ensuring smooth idle operations at both run and test positions, thereby enhancing the overall performance of the vacuum circuit breaker.
Implementation Method 1
a lead screw for moving the carrier in back and forth directions with respect to the cradle
Implementation Method 2
enhancing idle operation reliability by attenuating axial forces through a thrust bearing
Data Source
AI summary
Disclosed is a withdrawable device of main circuit for a circuit breaker. A ring-shaped guide recess is formed at a central part of a transfer nut screw-coupled to a lead screw, and supporting surfaces are formed on side surfaces of the guide recess. And, rotation prevention pins are elastically supported by springs in a moving direction of the transfer nut, and are selectively locked, thereby allowing the transfer nut to perform an idle operation. Accordingly, a structure for an idle operation of the transfer nut is simplified, and the number of components is reduced. An axial load is attenuated to a plane-contact distributed load, not a point-contact concentrated load, thereby preventing damage of the components. Also, a vacuum circuit breaker has enhanced reliability of the idle operation at a run position and a test position.