Fluid Pressure Cylinder with Variable Wall Thickness

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Solution Overview

Problem

Conventional fluid pressure cylinders have a uniform outer diameter, leading to increased weight due to excessive wall thickness where supply/discharge ports are not required, compromising weight reduction while maintaining strength.

Innovation Solution

The cylinder tube undergoes a spinning process to reduce wall thickness at portions without high strength requirements, maintaining strength at critical areas with larger diameters for supply/discharge ports and holding members.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the wall thickness of the cylinder tube is increased to ensure strength at supply/discharge ports, then the strength is improved, but the weight of the cylinder tube increases

Engineering Contradiction:
Improvestrength of cylinder tubeVSAvoidweight of cylinder tube
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The cylinder tube is designed with varying wall thickness along its length, with thicker sections at supply/discharge ports where strength is required and thinner sections in intermediate portions where strength requirements are lower. This local quality variation allows the tube to maintain necessary strength while reducing overall weight compared to a uniform thickness design.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The cylinder tube is divided into multiple sections with different wall thickness characteristics: first and second supply/discharge port portions with greater thickness for strength, and intermediate portions with reduced thickness for weight savings. This segmentation allows optimization of each section according to its specific functional requirements.

Inventive Principle:
Principle #1Segmentation

2Weight of moving object

If the outer diameter of the cylinder tube is reduced to decrease weight, then the weight is reduced, but the strength at critical areas may be compromised

Engineering Contradiction:
Improveweight of cylinder tubeVSAvoidstrength at supply/discharge ports
Core Design Contradiction:
Weight of moving objectVSStrength

Solution Approach 1:

The cylinder tube features local variations in outer diameter, with larger diameters at supply/discharge ports where strength and attachment requirements are critical, and smaller diameters in intermediate portions to reduce weight. This local quality approach ensures that weight reduction does not compromise the strength at critical areas.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The tube is segmented into regions with different outer diameters: enlarged portions at supply/discharge ports for strength and attachment, and reduced portions in between for weight savings. This segmentation enables the tube to achieve lower overall weight while maintaining adequate strength at critical locations.

Inventive Principle:
Principle #1Segmentation

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

Achieves weight reduction of the cylinder tube while ensuring sufficient strength at critical areas, optimizing the design for reduced weight and maintained performance.

Implementation Method 1

The cylinder tube undergoes a spinning process to reduce wall thickness at portions without high strength requirements

Methodology Applied
Scientific EffectSpinning process: Cold-forming

Data Source

PatentEP2952751B1Fluid pressure cylinder and method of manufacturing the cylinder
Publication Date: 2018.06.27 KYB YS CO LTD
  • EP2952751B1 patent drawingFigure 1
  • EP2952751B1 patent drawingFigure 2
  • EP2952751B1 patent drawingFigure 3

AI summary

A fluid pressure cylinder extends and contracts in accordance with supply/discharge of fluid pressure to/from a cylinder tube is provided. On inner side of both end portions of the cylinder tube in an axial direction, at least one small-diameter portion having a diameter smaller than those of the end portions in the axial direction is formed by a spinning process.