Air Cylinder Fluid Circuit for Independent Supply and Exhaust Control

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Solution Overview

Problem

Existing fluid circuits for air cylinders lack the ability to independently adjust the supply and discharge rates while maintaining a simplified structure.

Innovation Solution

A fluid circuit for air cylinders that includes two speed control valves, a switching valve, and check valves to allow independent adjustment of supply and discharge rates, with a simplified structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a throttle valve is placed on the exhaust path to control discharge rate, then the discharge rate can be adjusted, but the supply rate cannot be adjusted independently

Engineering Contradiction:
Improvedischarge rateVSAvoidindependent adjustment capability
Core Design Contradiction:
SpeedVSAdaptability or versatility

Solution Approach 1:

The fluid circuit is segmented into separate supply path and exhaust path, each with its own speed control valve. This allows independent adjustment of supply rate and discharge rate without interfering with each other, resolving the contradiction between discharge rate control and independent adjustment capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different control characteristics are applied to different parts of the system: the supply path has a speed control valve for controlling air intake rate, while the exhaust path has another speed control valve for controlling exhaust rate. This local differentiation enables independent adjustment of both rates.

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If multiple valves are added to enable independent adjustment of supply and discharge rates, then adjustment flexibility improves, but device complexity increases

Engineering Contradiction:
Improveindependent adjustment capabilityVSAvoidnumber of valves
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Each speed control valve is designed to perform multiple functions: controlling flow rate, maintaining pressure stability, and working in conjunction with check valves to enable bidirectional flow control. This multi-functionality reduces the need for additional specialized components, thereby limiting complexity growth while maintaining adjustment flexibility.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Loss of energy

If discharge rate is reduced to save energy and extend return time, then energy efficiency improves, but productivity decreases

Engineering Contradiction:
Improveenergy consumptionVSAvoidreturn speed
Core Design Contradiction:
Loss of energyVSProductivity

Solution Approach 1:

The system uses dynamically adjustable speed control valves that can change their flow resistance characteristics during operation. This allows the discharge rate to be optimized in real-time: reduced when energy saving is priority, increased when quick return is needed, thus resolving the contradiction between energy efficiency and productivity.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The flow rate parameters are made changeable through adjustable speed control valves. By changing the valve opening degree, the system can adjust the discharge rate to match different operational requirements, enabling trade-off between energy saving and return speed based on actual needs.

Inventive Principle:
Principle #35Parameter changes

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

Enables independent adjustment of supply and discharge rates, reducing stroke time during the drive process and increasing pressure after the return process, while maintaining a simplified structure.

Implementation Method 1

A first speed control valve allowing manual adjustment of a flow rate of air discharged from the second air chamber

Methodology Applied
Scientific EffectThrottling:

Implementation Method 2

A second speed control valve allowing manual adjustment of a flow rate of air supplied to the second air chamber

Methodology Applied
Scientific EffectThrottling:

Data Source

PatentEP3808992B1Fluid circuit of air cylinder
Publication Date: 2026.04.01 SMC CORP
  • EP3808992B1 patent drawingFigure 1A~1B
  • EP3808992B1 patent drawingFigure 2A~2B
  • EP3808992B1 patent drawingFigure 3

AI summary

A first fluid circuit (10A) is a fluid circuit of an air cylinder that comprises: an air cylinder (30) with a first air chamber (42a) and a second air chamber (42b) that are defined by a piston (38); a switching valve (16) that is switched between the drive step and return step of the piston (38); a first flow channel (12a) between the first air chamber (42a) and the switching valve (16); and a second flow channel (12b) between the second air chamber (42b) and the switching valve (16). Two speed control valves (50a, 50b) are provided in series in the second flow channel (12b).