Single-Acting Air Cylinder Positioning Control via Pneumatic Pressure

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Solution Overview

Problem

Single-acting air cylinders face challenges in arbitrarily changing or adjusting the movement position of their piston, as the moving stroke is mechanically determined and difficult to modify, leading to inefficiencies in workpiece conveyance and operations.

Innovation Solution

A positioning control mechanism using a pressure-adjusting apparatus with an electromagnetic automatic valve, a controller, and a return spring, allowing for precise control of air pressure to adjust the piston's position electronically, without mechanical adjustments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the moving stroke of the piston is mechanically determined by a stopper, then the structure is simple and reliable, but the movement position cannot be arbitrarily changed or adjusted

Engineering Contradiction:

Improveadjustability of movement positionVSAvoidstructural complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical stopper-based positioning system with a pneumatic pressure control system. By controlling the air pressure in the pressure chamber, the piston can be positioned at arbitrary locations without mechanical adjusters or stoppers. The pressure control unit electronically regulates pressure to balance against the return spring force, achieving position control without mechanical complexity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the control parameter from mechanical position (stopper location) to pneumatic pressure. By varying the air pressure supplied to the pressure chamber, the piston position can be continuously adjusted. The relationship between pressure and position is established through the spring force characteristics, allowing arbitrary positioning through pressure parameter control.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If an electric actuator is used to achieve free adjustment of movement position, then the positioning flexibility is improved, but the structure becomes complicated and size increases

Engineering Contradiction:

Improvepositioning flexibilityVSAvoidactuator structure complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent uses a pneumatic system instead of an electric actuator to achieve position control. The air cylinder with pressure chamber and return spring creates a simple pneumatic-mechanical system that provides linear movement and positioning flexibility without the complexity of electric motors, gearboxes, or encoders required in electric actuators.

Inventive Principle:

Principle #29Pneumatics and hydraulics

Solution Approach 2:

The patent substitutes the electric actuator's electromagnetic drive mechanism with a pneumatic drive system. The compressed air directly acts on the piston to produce motion, eliminating the need for complex electric actuator components while maintaining positioning flexibility through pressure control.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Force

If large force is obtained from an electric actuator, then the force capability is improved, but the actuator size and power consumption increase

Engineering Contradiction:

Improveforce of applicationVSAvoidelectric power consumption

Core Design Contradiction:

ForceVSUse of energy by moving object

Solution Approach 1:

The patent employs pneumatic pressure to generate large forces on the piston. Compressed air systems can deliver high forces without the size and power consumption penalties of electric actuators. The force is generated by pressure differential across the piston area, providing high force density without continuous power consumption.

Inventive Principle:

Principle #29Pneumatics and hydraulics

Solution Approach 2:

The patent converts the elastic potential energy stored in the compressed return spring into useful mechanical work during the return stroke. The spring, which would normally be considered a passive component, actually provides force assistance during retraction, reducing the energy required for full cycle operation.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

4Reliability

If a mechanical stopper is used to regulate piston position, then the positioning is reliable, but it is difficult to change or adjust the moving stroke

Engineering Contradiction:

Improvepositioning reliabilityVSAvoidease of adjusting moving stroke

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent replaces the mechanical stopper regulation system with electronic pressure control. The pressure control unit allows easy adjustment of piston position by changing pressure parameters without mechanical disassembly or repositioning of stoppers. Position changes are achieved through electronic control signals that adjust pressure, maintaining reliability while improving ease of operation.

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

Enables the arbitrary adjustment of the piston's movement position in single-acting air cylinders, improving operational flexibility and reducing energy consumption by allowing precise positioning without mechanical complexity.

Implementation Method 1

The pressure-adjusting apparatus is formed of an electromagnetic operation-type automatic pressure-adjusting valve that outputs the air pressure corresponding to an amount of electric power

Methodology Applied

Scientific EffectElectromagnetic operation: Electromagnet

Implementation Method 2

a return spring (12) at the other side, and the piston (10) is moved by means of an acting force of pressurized air supplied to the pressure chamber (11) and a spring force of the return spring (12)

Methodology Applied

Scientific EffectSpring force: Spring

Implementation Method 3

the piston (10) is moved by means of an acting force of pressurized air supplied to the pressure chamber (11)

Methodology Applied

Scientific EffectAir pressure: Pressure Increase

Data Source

PatentUS7886652B2Positioning control mechanism for single-acting air cylinder

Publication Date: 2011.02.15 SMC CORP

AI summary

An electromagnetic operation-type automatic pressure-adjusting valve outputting an air pressure corresponding to an amount of electric power is connected in an air flow path connecting a pressure chamber of a single-acting main cylinder and an air source. A controller is configured to obtain a relationship between a position of a piston and an air pressure from a relationship between the position of the piston of the main cylinder and a spring force of a return spring, and a relationship between the air pressure supplied to the pressure chamber and an acting force applied to the piston by the air pressure. When a target position of a movement of the piston is inputted to the controller, the controller is operated to move the piston toward the target position and to stop the piston at the position by means of controlling the amount of electric power for the automatic pressure-adjusting valve so that an air pressure corresponding to the target position is outputted.