Hydraulic Cylinder Buffer Sleeve Throttling Mechanism

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Solution Overview

Problem

Existing hydraulic oil cylinders with large diameters and long strokes face challenges in buffer protection due to high manufacturing precision requirements and potential failures in buffer mechanisms, leading to operational issues and restricted production capacity.

Innovation Solution

A hydraulic oil cylinder with a buffer sleeve that axially slides on the piston rod, forming a sealing surface to block oil passage and utilizing a throttling oil channel with varying cross-sectional area to provide a reliable buffer effect, reducing manufacturing precision needs and enhancing operational stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a compression spring is used as a buffer device in a hydraulic oil cylinder with large cylinder diameter and long stroke, then the buffer device is simple in structure, but the spring will be damaged soon because of being repeatedly compressed under great pressure

Engineering Contradiction:
Improvebuffer device structureVSAvoidspring durability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent replaces the mechanical spring buffer with a hydraulic buffer mechanism that uses oil pressure and throttling channels to provide buffering. The buffer sleeve and buffer inner hole create a throttling oil channel that controls oil flow, converting mechanical energy into hydraulic resistance, thereby avoiding spring damage while maintaining simplicity.

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Reliability

If a hydraulic buffer mechanism with buffer sleeve and buffer inner hole is used, then the buffer protection is effective, but the manufacturing precision requirement becomes extremely high

Engineering Contradiction:
Improvebuffer protection effectivenessVSAvoidfitting precision between buffer sleeve and buffer inner hole
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent modifies the geometric parameters of the buffer mechanism, specifically designing the buffer inner hole with a larger diameter than the buffer sleeve outer diameter to create a deliberate gap. This parameter change transforms the fitting from a precision interference fit to a gap-based throttling mechanism, significantly reducing manufacturing precision requirements while maintaining buffer effectiveness.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the fitting interspace between buffer sleeve and buffer inner hole is very small, then the buffer effect is good, but the piston rod is easy to be tilted to one side under gravity, causing buffer mechanism failure

Engineering Contradiction:
Improvebuffer effectVSAvoidpiston rod alignment stability
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent introduces an intermediary element - the throttling oil channel formed by the gap between the buffer sleeve and buffer inner hole - that mediates between the need for small clearance (for buffer effect) and large clearance (for alignment stability). The oil channel provides hydraulic damping that stabilizes the piston rod while maintaining the necessary gap for buffer functionality.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 ensures reliable buffer protection under high load and frequency conditions, extending the service life of hydraulic oil cylinders and simplifying manufacturing, thereby improving production capacity and reducing operational failures.

Implementation Method 1

a throttling oil channel is formed by a gap between the big buffer sleeve 04 and the buffer inner hole 07; so that, a piston 05 can continue to move in an extending direction, however due to a buffer effect of the throttling oil channel, the movement speed of the piston 05 is slowed down

Methodology Applied
Scientific EffectViscous damping: Viscous Damping

Data Source

PatentEP2597319B1Hydraulic oil cylinder, correlative device thereof, hydraulic cushion system, excavator and concrete pump truck
Publication Date: 2018.09.19 HUNAN SANY INTELLIGENT CONTROL EQUIP
  • EP2597319B1 patent drawingFigure 1~2
  • EP2597319B1 patent drawingFigure 3~4
  • EP2597319B1 patent drawingFigure 5~6

AI summary

A hydraulic oil cylinder has a cushion collar (4), which is sleeved in the cushion position of a piston rod and can axially slide along the piston rod (3). In the oil cylinder cavity between an oil hole (1-1) of the rod cavity and the terminal position of the piston end surface of the rod cavity during the piston (6) extending movement, a sealing end surface of the rod cavity (1-2) is provided, which can block the cushion collar and contact with the first end surface of the cushion collar to form a sealing surface. At least a throttle oil channel (3-5) is provided between the cushion collar and the piston rod. During the piston extending movement, from the moment that the first end surface of the cushion collar contacts with the sealing end surface of the rod cavity and a sealing surface is formed to the moment that the piston reaches the terminal position of the extending movement, the hydraulic oil at the side of the sealing surface close to the piston can be discharged towards the oil hole of the rod cavity through the throttle oil channel. The hydraulic oil cylinder has advantages of facility of manufacturing the cushion structure and good effect. The hydraulic oil cylinder can be used in a hydraulic cushion system, an excavator and a concrete pump truck.