Railway Coupling Buffer Gear With Series Spring-Damper Layout
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Solution Overview
Problem
Existing train coupling devices face issues with load changes causing adverse effects on train dynamics, require complex installation due to fixed spring characteristics, and have components prone to wear and failure, especially hydraulic dampers with limited damping at low speeds and high maintenance needs.
Innovation Solution
A train coupling device combining a hydraulic or pneumatic damper with a compression spring, arranged in series, where the spring constant is smaller than the damper's, allowing the damper to be effective only at high forces, while the spring absorbs most strokes, reducing wear and enabling easy adaptation to various installation spaces without additional spacers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single spring transmits both tensile and compressive forces in a draw and buffer device, then the device structure is simplified, but the load change with zero crossing adversely affects train dynamics and the spring travel cannot be changed without altering spring characteristics
Solution Approach 1:
The spring assembly is segmented into a first spring and a second spring arranged in parallel, where the first spring transmits compressive forces and the second spring transmits tensile forces. This segmentation allows independent optimization of each spring's characteristics and travel, resolving the contradiction between simplified structure and adaptability.
Solution Approach 2:
The housing structure serves multiple functions: it contains both springs, provides mounting connections, and incorporates adjustable spacers that can modify the effective travel of both springs simultaneously. This multi-functionality maintains structural simplicity while enabling travel adjustment.
2Adaptability or versatility
If additional spacers are provided in the installation space to transfer compressive forces, then the spring travel can be adjusted, but this involves additional effort and weight for the draw and buffer device
Solution Approach 1:
The housing is designed as a multi-functional component that simultaneously provides structural support, contains both springs, and incorporates adjustable spacers for travel modification. This eliminates the need for separate, heavy spacer components while maintaining adjustability.
Solution Approach 2:
The adjustable spacers are integrated into the housing structure rather than being separate components. This merging of functions reduces the overall component count and weight while preserving the ability to adjust spring travel.
3Object-affected harmful factors
If a hydraulic damper is used to cushion compression shocks, then compression forces are damped, but the damping effect is dependent on mass and speed resulting in hardly any damping at low speeds and complete failure upon damper failure
Solution Approach 1:
The force transmission path is segmented into a first spring for compression forces and a second spring for tension forces, with the hydraulic damper positioned to act only on the first spring. This segmentation allows the damper to operate optimally in compression while the second spring maintains reliability in tension.
Solution Approach 2:
The first spring acts as an intermediary between the compression force and the hydraulic damper, allowing the damper to cushion compression shocks effectively while the second spring serves as a backup for reliability in tension scenarios.
4Object-affected harmful factors
If compression springs are arranged in parallel to cushion both compression and tensile shocks, then the damping effect is improved, but the device requires considerable axial installation space
Solution Approach 1:
The housing structure utilizes radial space for the parallel spring arrangement rather than extending axially. By organizing the first and second springs in parallel within the housing's radial dimension, the design achieves effective shock cushioning in both directions while minimizing axial installation space.
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 provides a durable, cost-effective, and adaptable train coupling with reduced wear and maintenance, maintaining consistent spring constant over time, and minimizing damper usage for high-force shocks, enhancing train dynamics and ease of installation.
Implementation Method 1
a spring assembly that transmits tensile and compressive forces between opposing first and second connections of the traction and shock device
Implementation Method 2
a hydraulic or pneumatic damper with a compression spring, arranged in series
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The invention relates to a draw and buffer gear for a railway coupling, in particular a central-buffer coupling, having a first connection for a coupling pin and a second connection designed for securing the draw and buffer gear to a vehicle structure; and having a spring array which transmits tractive and compressive forces between the first connection and the second connection; wherein the spring array (4) comprises a compression spring (5) and a hydraulic and/or pneumatic damper (6); and the compression spring (5) and the damper (6) are arranged in series in the power flow from the first connection (1) to the second connection (2), such that compressive forces are transmitted from the compression spring (5) to the damper (6). The draw and buffer gear according to the invention is characterized in that a spring constant of the compression spring (5) is smaller than a spring constant of the damper (6).