Sleeve Buffer Plunger Friction Energy Dissipation

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Solution Overview

Problem

Existing sleeve buffers for rail vehicles and fixed structures face challenges in effectively absorbing and managing impact forces, particularly high-impact collisions, which can lead to structural damage and energy dissipation through irreversible deformation, without adequately protecting the supporting structures or rail vehicles from transverse forces.

Innovation Solution

A sleeve buffer design featuring a ram divided into two sections with increased friction in the first section, where the ram is partially encased, allowing for enhanced energy absorption through increased friction and potential additional deformation mechanisms, such as breaking connections or machining, to manage both longitudinal and transverse forces without additional components like springs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the sleeve buffer uses a spring to absorb impact energy, then the buffer can return to its original position, but the energy absorption capacity is limited and cannot handle high-impact collisions

Engineering Contradiction:
Improveenergy absorption capacityVSAvoidstructural integrity under high impact
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The buffer structure is divided into multiple sections with predetermined breaking connections between them. During normal operation, the spring absorbs energy reversibly. During high-impact collisions, the breaking connections fail in sequence, allowing the buffer to collapse progressively and absorb large amounts of energy through plastic deformation, preventing catastrophic failure of the entire structure

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The buffer design incorporates elements that change their mechanical properties under different load conditions. The predetermined breaking connections are designed to fail at specific force thresholds, transitioning the buffer from an elastic state (normal operation) to a plastic deformation state (high impact), thereby increasing energy absorption capacity

Inventive Principle:
Principle #35Parameter changes

2Loss of energy

If the sleeve buffer allows plastic deformation to absorb energy, then high-impact energy is dissipated, but the buffer structure is damaged and cannot be reused

Engineering Contradiction:
Improvekinetic energy dissipationVSAvoidbuffer reusability
Core Design Contradiction:
Loss of energyVSEase of repair

Solution Approach 1:

The buffer is segmented into replaceable sections connected by predetermined breaking connections. When high-impact energy needs to be absorbed, only specific sections fail while others remain intact, allowing the buffer to be repaired by replacing only the damaged segments rather than the entire structure

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The predetermined breaking connections are designed as sacrificial elements that can be easily replaced. These connections are intentionally made to fail under high impact, absorbing energy through their destruction, while the main buffer structure remains reusable after replacing these inexpensive components

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Volume of moving object

If the ram is fully received in the sleeve, then the buffer structure is compact, but transverse forces cannot be effectively managed

Engineering Contradiction:
Improvebuffer compactnessVSAvoidtransverse force impact
Core Design Contradiction:
Volume of moving objectVSObject-affected harmful factors

Solution Approach 1:

The guide parts are designed with geometric features that provide guidance not only in the longitudinal direction (primary buffer stroke) but also in transverse directions. The bearing surfaces and geometric constraints extend into the transverse dimension, preventing lateral movement and managing transverse forces while maintaining a compact overall structure

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

4Ease of repair

If the sleeve buffer is designed for reversible compression, then the buffer can be reused, but energy absorption during high-impact collisions is insufficient

Engineering Contradiction:
Improvebuffer reusabilityVSAvoidimpact energy absorption
Core Design Contradiction:
Ease of repairVSLoss of energy

Solution Approach 1:

The buffer combines reversible (spring) and irreversible (breaking connections) elements in segmented sections. During normal operation, the spring provides reversible energy absorption. During high-impact collisions, the breaking connections fail in sequence, enabling progressive collapse and large energy absorption, while the intact sections remain for potential reuse after replacing the failed connections

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The predetermined breaking connections are pre-designed and positioned to fail at specific energy thresholds. This beforehand preparation ensures that when high-impact collisions occur, the buffer automatically transitions to a high energy-absorption mode through controlled failure of these pre-positioned elements, protecting the main structure

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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

This design enhances energy absorption and structural support during impacts, reducing damage to the rail vehicle and supporting structures by utilizing increased friction and potential deformation mechanisms, effectively managing both longitudinal and transverse forces, thereby offering improved safety and energy dissipation.

Implementation Method 1

the force is usually absorbed by a spring, the elasticity of which causes the plunger to return to its original position relative to the sleeve when the force is removed

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

the first plunger section has a recess at least in sections, in which the diameter is initially reduced compared to the second plunger section, so that an increased friction or improved support is achieved in this area

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3771609B1Sleeve buffer with partially sheathed tappet
Publication Date: 2022.05.18 SCHNEIDER FALK
  • EP3771609B1 patent drawingFigure 1

AI summary

A sleeve buffer (1) with increased safety for support structures (11) is proposed, comprising a first and a second guide element (2, 3) in the form of a sleeve (3) and a plunger (2), wherein the sleeve (3) can be fixedly attached to the support structure (11) and the plunger (2) is displaceable relative to the sleeve (3) in the longitudinal direction of the vehicle, wherein the plunger is divided into at least two plunger sections (5, 6), wherein the second plunger section (6) is arranged overlapping with the sleeve (3) without the application of an impact force to the sleeve buffer (1), and the first plunger section (5) has at least a partial recess by which its diameter is reduced compared to the second plunger section (6), wherein a structure (7) is inserted into the recess, at least partially, and in particular completely, surrounding or encasing the plunger, in order to reduce the energy dissipation induced by friction between the plunger (2) and the sleeve (3). to enlarge / to increase support against lateral forces.