Development of a new high-precision friction test platform and experimental study of friction characteristics for pneumatic cylinders

Abstract

In order to achieve high-precision pneumatic cylinder friction test, this paper proposes a new direct measurement method based on electric cylinder in which the axially acting forces from the compressed air in the two facing pneumatic cylinders cancel each other out and the detected value of the force transducer is just friction. For the sake of the implementation of the method, a new low-cost test method for identifying deadband of proportional directional valve was proposed, and a set of fuzzy PI constant pressure control system was designed to cope with a certain degree of leakage in the chamber. Based on the above, a friction test platform with two pneumatic cylinders facing each other was eventually built to study the influence of pressure, pressure difference, and piston speed on the friction of two commonly used different types of pneumatic cylinders. Through multiple sets of tests, it is found that when the lip seals are used in pairs between the piston and the inner wall of the cylinder, the friction between the piston and the cylinder is only related to the sum of the two chamber pressures, but not to the pressure difference between the two chambers; When the O-ring seal is used between the piston and the inner wall of the cylinder, the friction between the piston and the cylinder is related not only to the pressure of the two chambers, but also to the pressure difference between the two chambers. In addition, a series of comparative tests with the traditional single-cylinder friction test method directly demonstrate the effectiveness of the proposed new method.

Failure and Damage of Reciprocating Lip Seals for Pneumatic Cylinders in Dry Conditions

“…Wear and failure modes of lip seals [15], including adhesion-abrasion mechanisms [16], are, in turn, related to contact pressure distribution and friction. Investigations into the contact mechanics and frictional behaviour of reciprocating lip seals were presented in [17][18][19][20][21] through experimental and numerical approaches. The importance of investigating contact forces and friction forces on actual seals was also shown by Juoksukangas et al [22] instead of resorting to laboratory testing on samples [23].…”

Vibration and stability analyses of rotor–bearing-casing system in an axial piston pump subjected to bearing faults

“…With the development of thermal control technology and fluid mechanics theory, fluid transmission and control technology have progressed rapidly. 1,2 An axial piston pump is a rotating machine with fluid-solid coupling that is widely used in industrial machinery to provide hydraulic power. A rotor-bearing system is the primary moving part that converts mechanical energy into hydraulic energy.…”

Investigation on the transient impact characteristics of fast switching valve during excitation stage

“…Traditional fluid transmission systems consisted by several proportional/servo valves are widely used in aerospace, ship, and construction machinery fields due to the advantages of high power density, high dynamic, and high precision. [1][2][3][4] Compared to the proportional/servo valve, a fast switching valve (FSV) has several advantages, such as possible zero leakage, low cost, and high reliability, which is widely used in the digital hydraulic system [5][6][7][8] and high-pressure commonrail system. 9 The output flow of the FSV is depending on the ratio of opening time and closed time in a cycle, which is controlled by the duty ratio of the PWM (pulse width modulation).…”