Rail Vehicle Coupling With Insulating Torque-Limiting Bushing
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Solution Overview
Problem
Existing torque-transmitting couplings in drive trains, particularly in railway applications, require improved designs that incorporate electrical insulation and torque overload prevention while simplifying their structure and function.
Innovation Solution
A coupling design featuring a bushing made of high-performance plastic seated in a through-bore of the hub section, which provides electrical insulation and torque limitation, with interlocking gearing for torque transmission and a lubricant reservoir for maintenance-free operation, and a sealing element to compensate for angular changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a coupling is designed to transmit torque efficiently, then torque transmission capability is improved, but electrical insulation is compromised
Solution Approach 1:
The coupling is divided into electrically conductive components (hub sections, drive teeth) and an electrically insulating component (bushing). The bushing is segmented into a body portion for torque limitation and an extension portion for electrical insulation, allowing simultaneous achievement of torque transmission and electrical insulation.
Solution Approach 2:
The bushing acts as an intermediary element between the first and second hub sections. It provides both mechanical function (torque limitation through controlled slippage) and electrical function (insulation between conductive parts), mediating between the conflicting requirements of torque transmission and electrical insulation.
2Reliability
If a coupling includes torque limitation functionality, then overload protection is improved, but device complexity increases
Solution Approach 1:
The bushing combines multiple functions into a single component: electrical insulation, torque limitation through controlled slippage, and mechanical connection between hub sections. This merging eliminates the need for separate torque limiting devices, reducing overall complexity while maintaining overload protection.
Solution Approach 2:
The bushing is designed as a multi-functional element that simultaneously provides electrical insulation, torque limitation, and mechanical support. The body portion handles torque limitation through material deformation, while the extension portion provides electrical insulation, making the single component universally applicable to multiple requirements.
3Ease of manufacture
If a coupling uses conventional materials for bushing, then manufacturing is simplified, but temperature resistance and wear properties deteriorate
Solution Approach 1:
The bushing is made from a composite material or a specially formulated plastic that combines good manufacturability with high temperature resistance and excellent wear properties. This material selection resolves the contradiction by providing both ease of manufacturing through plastic forming and superior performance in demanding thermal and mechanical conditions.
4Ease of repair
If a coupling design allows easy replacement of wear parts, then maintenance time is reduced, but structural complexity increases
Solution Approach 1:
The coupling is segmented into modular components (hub sections, bushing, drive teeth) that can be independently accessed and replaced. The bushing is designed as a separate, replaceable component that can be removed and replaced without disassembling the entire coupling, enabling quick maintenance while maintaining a relatively simple overall structure.
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 design ensures efficient torque transmission with electrical insulation, reduces maintenance downtime, and allows for easy replacement of wear parts, enhancing the operational efficiency and reliability of drive trains.
Implementation Method 1
a bushing made of an electrically non-conductive high-performance plastic is seated in a through-bore of the hub section
Implementation Method 2
The coupling is a torsionally rigid coupling that transmits torque from a first shaft to a second shaft via interlocking external and internal gearing
Implementation Method 3
A reservoir for lubricant is advantageously provided between the hub section and the housing section. The drive teeth can be lubricated via this lubricant reservoir
Implementation Method 4
A sealing element can be provided between the hub section and the housing section to seal this reservoir from the environment. It is particularly preferred if the sealing element is not only able to carry out axial movement between the hub section and the housing part, but also to compensate for small swivel angles
Implementation Method 5
the couplings can be equipped with a slip element that prevents torque overload by acting as a torque limiter
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
Coupling (10, 100) for connection between a first shaft (2) and a second shaft (4), having a first coupling part (12) for connecting to the first shaft (2), and a second coupling part (14) for connecting to the second shaft (4), said second coupling part being connected to the first coupling part (12) for transmitting a drive torque, wherein at least one of the two coupling parts (12, 14) can have a driving toothing (16) with in each case inter-engaging inner toothing (18) and outer toothing (20). In an axial hub portion (22) of at least one of the two coupling parts (12, 14) there is seated a bushing (30) consisting of an electrically non-conductive high-performance plastic. The bushing (30) combines the two functions of electrical insulation between the two shafts (2, 4) and torque limiting in the event of an overload.