• KSTLE International Journal
• /
• v.10 no.1_2
• /
• pp.37-42
• /
• 2009

This paper presents the characteristics of volumetric efficiency of an axial type piston pump considering the piston tilting. A numerical analysis is carried out in order to obtain the pressure distribution considering the fluid inertia at the notch of the valve plate. The cylinder pressure variation and the discharge flow rate are measured experimentally according to the operating conditions such as supply pressure, rotational speed, and viscosity of the working fluid by using the cam type test apparatus. Leakage is also measured considering piston tilting. The characteristics of the volumetric efficiency are analyzed with respect to various operating conditions and leakage is also analyzed according to the piston tilting angle. Results are applicable to improve the design of an axial type piston pump.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.12 no.9
• /
• pp.717-724
• /
• 2002

In this study, a numerical analysis for the piston secondary dynamics of small refrigeration reciprocating compressors is performed. In general, the length of cylinder in this class of compressors is shortened to diminish the frictional losses of the piston-cylinder system. So, the contacting length between piston and cylinder wall is in variable with the rotating crank angle around the BDC of the reciprocating piston. In the problem formulation of the piston dynamics, the change in bearing length of the piston and all corresponding forces and moments are considered in order to determine the piston trajectory, velocity and acceleration at each step. A Newton-Raphson procedure was employed in solving the secondary dynamic equations of the piston. The developed computer program can be used to calculate the entire piston trajectory and the hydrodynamic force and moment as functions of crank angle under compressor running conditions. The results explored the effects of the radial clearance, lubricant viscosity, length of the cylinder wall, and pin location on the stability of the piston.

• Tribology and Lubricants
• /
• v.14 no.4
• /
• pp.51-57
• /
• 1998

Recently, bent-axis-type axial piston pumps driven by rods being in extensively used in the world, because of simple design, lightweight, effective cost. So, to guarantee the quality of bent-axis-type axial piston pumps driven by rods, it is necessary to know characteristics of the driving mechanism of rods. But, as they perform both reciprocating and spinning motions, it is difficult to understand driving mechanism. In this paper, I studied the theoretical driving mechanisms of cylinder block driven by rods through geometric method. I found that the cylinder block was driven by one rod in limited area and the driving area was changed by rod's tilting angle and cylinder block's swivel angle.

• Transactions of The Korea Fluid Power Systems Society
• /
• v.2 no.1
• /
• pp.1-8
• /
• 2005

Recently, swash plate type hydraulic axial piston motors/pumps are being extensively used in the world, because of simple design, light weight and effective cost. Structural problem of the swash plate type motor/pump is that tilting angle of swash plate should be limited to relatively small value and lateral farce on pistons has an undesirable effect in reciprocating motion. To solve these problems, piston rod mechanism, which is commonly used in bent axis type motor/pump, is considered to be applied to the swash plate type motor/pump. In this paper, kinematic analysis was done on the piston rod mechanism. A series of formula were derived and numerical calculations were done for a set of motor parameters.

• Journal of Drive and Control
• /
• v.17 no.1
• /
• pp.51-60
• /
• 2020

This study addresses the modeling of a bi-directional outlet variable swash plate type axial piston pump with two EPPR valves and an analysis of the response characteristics to the angle control of that pump. In this paper, the combination of the EPPR valve and double rod type piston is referred to as the EPPR regulator. The EPPR regulator is compact and inexpensive, and has good responsiveness. Under actual pump operating conditions, because of the various external conditions of the pump, inertia is applied to the swash plate, generating the tilting torque. Also, the tilting torque can delay or shorten the response characteristics of the regulator. So we validated them through the analysis using SimulationX and these results allow users to freely integrate the EPPR regulator into the desired system.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2002.10a
• /
• pp.721-724
• /
• 2002

This study deals with a dynamic behavior analysis of pump control regulator varied the swash plate tilting angle with the positive and negative direction. To accomplish it's purpose, modeling and displacement response analysis about principal parts (spool, servo piston, feedback lever, sleeve) of pump control regulator was performed. We have been able to verifying the propriety of servo mechanism and design parameters of pump control regulator by research results. So, it respect to utilized with useful research data at variable displacement control valve development of variable displacement piston pump.