Pilot Check Valve Flow Controller for Low-Cost Air Cylinder Speed Control

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Solution Overview

Problem

Conventional flow rate controllers for air cylinders are complex, requiring numerous components and costly production steps, especially when using three-way valves, which necessitate grinding or polishing, making them difficult to manufacture at a low cost.

Innovation Solution

A simplified flow rate controller design that eliminates the need for complex components like spools or shuttle valves by using a pilot check valve to control exhaust air flow, reducing the number of production steps and manufacturing costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a three-way valve with spool or shuttle is used to control exhaust air flow, then the flow rate control function is achieved, but the device complexity increases and manufacturing cost increases due to grinding or polishing requirements

Engineering Contradiction:
Improvemanufacturing costVSAvoiddevice complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent extracts the complex spool or shuttle valve components from the system and replaces them with a simpler check valve mechanism. The exhaust air flow control is achieved by selectively opening or closing the check valve based on cylinder position, eliminating the need for precision-ground spools or shuttles while maintaining the flow rate control function.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces expensive precision components (spools requiring grinding, shuttles requiring polishing) with a simpler, cheaper check valve mechanism. The check valve can be manufactured with standard tolerances without requiring costly precision surface treatment, significantly reducing manufacturing cost and complexity.

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

2Productivity

If a three-way valve is used to throttle exhaust air, then the operating speed control is achieved, but the number of production steps increases due to grinding or polishing requirements

Engineering Contradiction:
Improveproduction efficiencyVSAvoidnumber of production steps
Core Design Contradiction:
ProductivityVSEase of manufacture

Solution Approach 1:

The patent removes the three-way valve with its associated grinding or polishing production steps from the manufacturing process. Instead, it uses a check valve that can be manufactured with standard precision, eliminating the need for additional surface treatment steps and reducing overall production complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If conventional shock absorbing mechanisms using cushioning materials or oil dampers are used, then shock cushioning is achieved, but the service life is limited and regular maintenance is required

Engineering Contradiction:
Improveservice lifeVSAvoidnumber of operations
Core Design Contradiction:
ReliabilityVSDuration of action of moving object

Solution Approach 1:

The patent replaces mechanical shock absorbing mechanisms (cushioning materials, oil dampers) with a pneumatic control system that uses flow rate control of exhaust air. By controlling the exhaust air flow rate near the stroke end, the piston speed is reduced, providing shock cushioning without mechanical contact or wear-prone components, thereby extending service life and eliminating regular maintenance.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 simplified design allows for easier manufacturing and reduced costs while maintaining effective control over the operating speed of air cylinders, mitigating shocks and extending the service life of mechanism parts.

Implementation Method 1

a pilot check valve (48) disposed in the second flow path (44), and switching between a state in which the exhaust air is capable of passing through the second flow path (44) and a state in which the passage of the exhaust air through the second flow path (44) is blocked, depending on the pressure of the pilot air

Methodology Applied
Scientific EffectPneumatic pressure control: Pressure Gradient

Implementation Method 2

a first throttle valve (36) disposed in the first flow path (42), for throttling a flow rate of the exhaust air passing through the first flow path (42)

Methodology Applied
Scientific EffectThrottling: Pressure Drop

Implementation Method 3

a second throttle valve (38) disposed in the second flow path (44), for throttling a flow rate of the exhaust air passing through the second flow path (44)

Methodology Applied
Scientific EffectThrottling: Pressure Drop

Data Source

PatentEP4027023B1Flow rate controller and drive device equipped with same
Publication Date: 2024.12.04 SMC CORP
  • EP4027023B1 patent drawingFigure 1
  • EP4027023B1 patent drawingFigure 2
  • EP4027023B1 patent drawingFigure 3

AI summary

Provided are a flow rate controller (22, 22A) and a drive device (20) wherein a housing (30) is provided with, in the interior thereof, a first flow passage (42), a second flow passage (44) provided adjacent to the first flow passage (42), a first throttle valve (36) provided to the first flow passage (42), a second throttle valve (38) provided to the second flow passage (44), a pilot check valve (48) that is provided to the second flow passage (44) and is connected in series to the second throttle valve (38), a pilot air flow passage (46) that communicates with a pilot port (48c) of the pilot check valve (48) and is for supplying and discharging pilot air, and a third throttle valve (40) provided to the pilot air flow passage (46). In response to the pressure of the pilot air the pilot check valve (48) switches between a state in which the passage of exhaust air discharged from an air cylinder (10) is permitted and a state in which passage of the exhaust air is prevented.