Segmented Release Ring Radial Expansion for Coupler Bolt Shear
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Solution Overview
Problem
Existing rail transit vehicle coupler assemblies experience reduced fatigue strength in emergency release bolts due to bending forces during high coupling events, leading to premature failure.
Innovation Solution
A multi-segmented release ring with expandable split rings and threaded bores allows for radial expansion to eliminate gaps between the release ring and draft gear housing, ensuring pure longitudinal shearing and minimizing bending forces on emergency release bolts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a rigid emergency release ring is used in existing coupler assemblies, then the structure is simple and easy to manufacture, but the emergency release bolts experience bending forces during high coupling events that reduce fatigue strength
Solution Approach 1:
The release ring is divided into multiple segments that can expand radially independently. This segmentation allows the release ring to conform to the housing surface during high coupling events, eliminating gaps and preventing bending forces on the emergency release bolts while maintaining structural simplicity.
2Duration of action of stationary object
If a gap is left between the release ring and draft gear housing for assembly, then the assembly process is simplified, but forces repeatedly flex the emergency release bolts in bending mode reducing fatigue strength
Solution Approach 1:
The release ring segments are designed to be dynamically expandable radially during operation. This dynamic expansion eliminates gaps between the release ring and housing during high coupling events, preventing bending forces on the emergency release bolts while maintaining ease of assembly in the unexpanded state.
3Strength
If the release ring is pulled against the inside wall of the draft gear housing to form a contact at a single location, then the structure is simplified, but forces repeatedly flex the emergency release bolts in bending mode
Solution Approach 1:
The release ring is segmented into multiple sections that can expand radially to contact the housing at multiple locations simultaneously. This distributed contact approach eliminates the single-point contact that causes bending forces, while the segmented structure remains relatively simple and easy to manufacture.
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 enhances the fatigue life of emergency release bolts by eliminating bending forces and ensuring equal load distribution, thereby preventing premature failure and improving the reliability of the coupler assembly during emergency buffing events.
Implementation Method 1
The emergency release bolts are designed to shear and break in two pieces when the coupling forces between two vehicles exceed a designed limit as determined by the strength of the emergency release bolts
Implementation Method 2
A multi-segmented release ring with expandable split rings and threaded bores allows for radial expansion to eliminate gaps between the release ring and draft gear housing
Data Source
AI summary
A release device for a draft gear assembly comprises a draft gear housing for slidably supporting a yoke shaft and capturing a cushion unit associated with the yoke shaft between buff and draft stops. The buff stop comprises a release ring within the interior of the draft gear housing being radially divided into two or more sections. A plurality of release bolts designed to shear under emergency buffing forces extend through the draft gear housing and into the sections of the release ring to draw the sections radially outward to the interior surface of the draft gear housing eliminating gaps and minimizing flexing of the release bolts.