Railway Transmission Assembly Guide Ring Expansion
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Solution Overview
Problem
Current transmission assemblies for railway vehicles can only maintain a low running speed of about 80 km/h for a few hours after a mechanical failure, as the safety fuse breaks, limiting operational efficiency.
Innovation Solution
The transmission assembly incorporates an expandable guide ring and rolling bearings with a low coefficient of friction, which dilate upon temperature increase from friction, allowing the drive shaft to continue rotating at high speed by transitioning from contact with the guide ring to the rolling bearings, thereby maintaining high-speed operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the drive shaft breaks at the calibrated groove (safety fuse), then the mechanical failure is contained and prevents damage to other components, but the vehicle speed is limited to about 80 km/h for only a few hours
Solution Approach 1:
The guide ring is designed to dynamically change its internal diameter from a retracted state to an expanded state in response to temperature changes. This dynamic adaptation allows the system to transition from a high-friction bronze-on-steel contact to a low-friction rolling bearing contact, enabling high-speed operation after drive shaft rupture while maintaining safety protection.
Solution Approach 2:
The system changes the physical parameter of the guide ring's internal diameter based on temperature conditions. At normal temperatures, the guide ring maintains a smaller diameter for bronze contact. When temperature increases due to friction after rupture, the guide ring expands to a larger diameter, transitioning the contact mechanism to rolling bearings and enabling sustained high-speed operation.
2Device complexity
If the guide ring remains in retracted state with small internal diameter, then the structure is compact and simple, but the rolling bearings cannot engage to support high-speed rotation after rupture
Solution Approach 1:
The guide ring is designed to utilize thermal expansion to automatically transition between operational states. The increase in temperature caused by friction after drive shaft rupture triggers the guide ring to expand, increasing its internal diameter to allow rolling bearing engagement. This eliminates the need for complex control mechanisms while enabling high-speed operation.
Solution Approach 2:
The guide ring automatically adjusts its state based on the operational conditions without external intervention. The temperature increase from friction self-triggers the expansion mechanism, causing the guide ring to automatically transition to the expanded state where rolling bearings can support high-speed rotation, eliminating the need for external control systems.
3Speed
If the guide ring expands to dilated state with large internal diameter, then the rolling bearings can guide the drive shaft at high speed, but the radial stresses on the bearings increase
Solution Approach 1:
The guide ring acts as an intermediary element that mediates between the drive shaft and the rolling bearings. By expanding to increase its internal diameter, it allows the rolling bearings to engage with the drive shaft, providing guided rotation at high speeds while distributing and managing the radial stresses through its structural design.
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 railway vehicles to maintain commercial speed of at least 330 km/h for over 5000 km after the safety fuse rupture, while being simple, cost-effective, and easy to repair, with reduced radial stresses and frictional heat management.
Implementation Method 1
the guide sleeve further comprises at least one rolling bearing adapted to guide the driving end portion of the drive shaft in translation along the drive axis and in rotation about the drive axis
Implementation Method 2
rolling bearings with a low coefficient of friction
Implementation Method 3
the guide ring is expandable between an initial retracted state of small internal diameter and a dilated state of larger internal diameter, the internal diameter of the or each rolling bearing being greater than the internal diameter of the guide ring in its retracted state and smaller than the internal diameter of the guide ring in its dilated state
Data Source
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AI summary
This assembly comprises a drive shaft, which is rotatable about a drive axis, and a sliding connection module, the drive shaft comprising: - a driving end portion; - a connecting end portion drivingly connected to the connection module; and - a breakable portion which joins the driving and connecting end portions, and is adapted to break beyond a predetermined torque, the connection module comprising a connection casing which receives the connecting end portion so that it slidable along the drive axis and is coupled to the connection module in rotation, and a guide sleeve comprising a guide ring which guides the driving end portion in rotation and in translation. The guide sleeve further comprises at least a rolling bearing which is adapted to guide the driving end portion of the drive shaft in rotation and in translation. The guide ring is expandable between an initial retracted state of small internal diameter and a dilated state of larger internal diameter, the internal diameter of the rolling bearings being greater than the internal diameter of the guide ring in its retracted state and smaller than the internal diameter of the guide ring in its dilated state.