• Transactions of the Korean Society of Automotive Engineers
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• v.18 no.3
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• pp.95-103
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• 2010

This paper presents a simulation model of a double-acting high-speed pneumatic cylinder with a relief valve type cushion mechanism. The model predicts piston motion, mass flow rate, pressure and temperature time histories of cushion chamber. Of interest here is to investigate the cushioning effect of varying the piston and piston-rod diameter, cushion ring diameter and length, and stoke in cushion mechanism. As a result, this cushion mechanism is found to be adequate under high-speed driving of pneumatic cylinders. The simulation model proposed here will be very useful to analyze the dynamic characteristics and to improve or design the better cushion mechanism in high-speed pneumatic cushion cylinders.

• 유공압시스템학회:학술대회논문집
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• 2010.06a
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• pp.99-104
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• 2010

Nonlinear seal friction in pneumatic cylinders can impede the performance of pneumatic systems designed for high precision positioning with favorable high speed actuation. The behaviour of an elastomeric piston seal in high speed pneumatic cylinders is analysed by nonlinear finite element analysis using ABAQUS. The contact pressures, stress and strain distributions and frictional forces of the piston seal are simulated with variation of interference fits, supply pressures, friction coefficients and piston rod velocities. The nonlinear finite element model of the piston seal is used to predict deformation of a seal, friction force and contact pressure distributions.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.1
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• pp.1-7
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• 2013

Pneumatic cylinders are widely used to actuators in automatic equipments because they are relatively inexpensive, simple to install and maintain, offer robust design and operation, are available in a wide range of standard sizes and design alternatives. This paper presents a comparative study among the dynamic characteristics of meter-out and meter-in speed control of pneumatic cushion cylinders with a relief valve type cushion mechanism. Because of the nonlinear differential equations and a requirement for simultaneous iterative solution in a mathematical model of a double acting pneumatic cushion cylinder, a computer simulation is carried out to investigate pressure, temperature, mass flow rate in cushion chamber and displacement and velocity time histories of piston under various operating conditions. It is found that the piston velocity and pressure response in meter-in speed control are more oscillatory than with meter-out those when pneumatic cushion cylinders are driven at a high-speed. In meter-out speed control, the effective area of the flow control valve is larger than that of meter-in, and the supply pressure has to be much higher than the pressure required to move the load because it has also to overcome the back pressure in cushion chamber.

• Transactions of The Korea Fluid Power Systems Society
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• v.8 no.3
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• pp.21-26
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• 2011

Nonlinear seal friction in pneumatic cylinders can impede the performance of pneumatic systems designed for high precision positioning with favorable high speed actuation. The behaviour of an elastomeric piston seals in high speed pneumatic cylinders is analyzed by nonlinear finite element analysis using ABAQUS. The contact pressures, stress and strain distributions and frictional forces of the squeeze type piston seal are simulated with variation of the seal radial installed interference, the operating pressures, friction coefficients and piston rod velocities. The nonlinear finite element model of the squeeze type piston seal is used to predict deformation of a seal, friction force and contact pressure distributions.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.476-479
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• 1997

A Knowledge of friction force in pneumatic cylinders makes it possible to improve cylinder description during simulation and to asses performance under changing operating conditions more accurately. Such knowledge is particularly useful, for example, when modeling continuous pneumatic positioning systems or predicting the operating conditions under which stick slip may occur, as well as in establishing preventive maintenance procedures for pneumatic cylinders. Friction force depends on a number of factors, including operating pressure, seal running speed on the cylinder barrel and rod, barrel material and surface roughness, seal dimensions and profile, seal material, lubrication conditions, cylinder distortion during assembly, and the operating temperature of cylinder components. This paper shows a system for measuring the friction force caused by a seal used in pneumatic cylinders. Results of experimental tests show that seal friction forces for grease lubricated service are clearly dependent on speed and pressure and are les sensitivity to other parameter. i.e., barrel material and roughness, seal material, and profile.

• Journal of Drive and Control
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• v.12 no.1
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• pp.21-27
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• 2015

Pneumatic cylinders are classified into rod-type pneumatic cylinders and rodless pneumatic cylinders depending on the presence of the rod. Rodless cylinders have a constant area and have no deflection. Rodless cylinders are widely used in automatic systems requiring high-speed performance and high-precision transportation. However, the research of the pneumatic cylinder has been focused on the structure and life characteristics. In this research, aging characteristics and shape parameter analysis which are related to the lifetime were investigated. By conducting the lifetime tests with two different materials for the transfer plate, the failure mode and lifetime characteristics were analyzed. By the Anderson-Darling (A-D) verification based on the complete data set, the analysis results of lifetime distribution, shape parameter, and scale parameter were provided.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1230-1235
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• 2008

Of all of pneumatic components utilized in the make up of pneumatic circuits on either automatic assembly machine or industrial equipment, the pneumatic cylinder is more oriented toward being a structural as well as a pneumatic member. The structural design must be based to a large degree on the end of application of the cylinder on the equipment it is operating. In this paper, design studies of a double-acting pneumatic cushion type cylinder with low-friction and high-speed driving have been developed. Of interest here is to investigate the structural analysis of cylinder tube, piston rod, end cover, and to analyze the buckling of piston rod. Also, a relief valve type cushion mechanism is considered. This cushion mechanism is found to be adequate under a high-speed driving of pneumatic cylinders.

• Journal of Drive and Control
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• v.9 no.1
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• pp.18-24
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• 2012

The paper deals with the design of a new low-friction seal for a pneumatic cylinder with high speed actuation. The seal performance with variation of the cross sections in piston seals with elastomeric material was investigated to minimize the friction forces using ABAQUS. The contact stress and strain distributions and frictional forces of the piston seals were investigated with variation of interference fits, supply pressures and friction coefficients. To develop adequate and productive procedures, the finite element models of the piston seals were created and nonlinear analysis of a seal design was conducted in order to build further knowledge and understanding of the seal's performance characteristics.

• Journal of Drive and Control
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• v.12 no.4
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• pp.54-59
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• 2015

Due to the tendency to use high speed pneumatic cylinders to improve productivity, cushioning devices are adopted to decelerate the piston motion of pneumatic cylinders to reduce noise, vibration, and impact. This paper presents a comparison of the cushion characteristics of a high speed pneumatic cylinder with a relief valve type cushioning device. The system parameters selected are the damping coefficient, Coulomb friction, heat transfer coefficient, and cracking pressure of the relief valve in the air cushioning device. The integral of the time multiplied square error (ITSE) is used to quantitative measure the cushioning performance to assess the effect of varying these. The cushioning performance achieved good results when the ITSE is a minimum value. In a comparison of the piston displacement and velocity with the variations in system parameters, the heat transfer coefficients are not as significantly affected as the other. Also, the cracking pressure of the relief valve is mainly affected by the pressure and temperature in the cushion chamber.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.6
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• pp.24-30
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• 2013

This paper studies the comparative analysis on two different internal cushion devices (the types of needle and relief valve) used to absorb the energy which is generated when the pneumatic cylinder moves with the load at meter-out speed control system. The effect at varying the piston velocity under same driving condition is mainly investigated. The simulation results on pressure in the cushion chamber and the dynamic behavior of the relief valve type cushion device are compared with the needle valve type. Design and performance are improved with the cushion configuration of better quality at high-speed pneumatic cylinder. Based on the relation between absorbed energy and impact energy at cushion process, cushion performance at pneumatic cylinder is evaluated.