Mixed Lubrication Characteristics Between the Piston and Cylinder in Hydraulic Piston Pump-Motor

1995 ◽  
Vol 117 (1) ◽  
pp. 80-85 ◽  
Author(s):  
Yi Fang ◽  
Masataka Shirakashi
Keyword(s):  
Numerical Analysis ◽  
Mixed Lubrication ◽  
Operating Conditions ◽  
Piston Pump ◽  
Experimental Result ◽  
Contact Ratio ◽  
Supply Pressure ◽  
Swash Plate ◽  
Lubrication Characteristics ◽  
Plate Type

This paper presents a method for evaluating the lubrication characteristics between the piston and cylinder in a swash-plate type axial piston pump-motor under mixed lubrication conditions. A numerical analysis is carried out in order to obtain the metal contact force between the piston and cylinder, and the contact ratio λ is shown to represent the mixed lubrication condition both for the pump and the motor strokes. The contact ratio, λ, is also obtained experimentally by detecting electric resistance between the piston and cylinder in a practical swash-plate type machine. The experimental result is expressed by a relationship between λ and SO (the ratio of dynamic pressure to supply pressure) as indicated by the numerical analysis. In conclusion, the mixed lubrication characteristics between the piston and cylinder in a swash-plate type pump-motor is expressed by λ−SO curve irrespective of the operating conditions such as the supply pressure or the rotation speed.

Lubrication characteristics of the slipper–swash-plate interface in a swash-plate-type axial piston pump

2020 ◽  
pp. 095440622093294
Author(s):  
Xiangxu Meng ◽  
Chang Ge ◽  
Hongxi Liang ◽  
Xiqun Lu ◽  
Xuan Ma
Keyword(s):  
Hydrodynamic Lubrication ◽  
Piston Pump ◽  
Axial Piston Pump ◽  
Plate Interface ◽  
Load Pressure ◽  
Swash Plate ◽  
Lubrication Performance ◽  
Lubrication Characteristics ◽  
Axial Piston ◽  
Plate Type

An analytical approach based on a hydrodynamic lubrication model is presented to understand the bearing capacity, leakage, and friction moment of the slipper–swash-plate interface in a swash-plate-type axial piston pump. Furthermore, how the shaft speed, load pressure, and slipper attitude influence the lubrication performance of the interface is analyzed. The research shows that the slipper attitude has a significant effect on the pressure distribution. To improve the lubrication performance, a grooved sealing-land design is proposed, and the location and geometric parameters of the groove are analyzed. The results indicate that the optimal lubrication performance is achieved when the groove is 2.0–3.0 mm wide and 5–20 µm deep at its inner boundary.

Half-frequency whirl of pistons in axial piston pumps and motors under mixed lubrication

2003 ◽  
Vol 217 (2) ◽  
pp. 93-102 ◽  
Author(s):  
K Tanaka ◽  
T Nakahara ◽  
K Kyogoku
Keyword(s):  
Mixed Lubrication ◽  
Operating Conditions ◽  
Axial Piston Pump ◽  
Piston Motion ◽  
Axial Piston Pumps ◽  
Supply Pressure ◽  
Oil Whirl ◽  
Lubrication Characteristics ◽  
Axial Piston ◽  
Lubrication Conditions

Dynamic lubrication characteristics between a piston and a cylinder in an axial piston pump and motor have been calculated under mixed-lubrication conditions. The calculated results have shown that half-frequency whirling of the piston occurs under some operating conditions and specifications such as low supply pressure, narrow clearance and long sealing length between the piston and the cylinder, in a manner similar to the oil whirl phenomenon in journal bearings. The whirl phenomenon has been confirmed by measurements of piston motion.

scholarly journals Pressure compensator design, simulation and performance evaluation of a variable displacement swash plate type axial piston pump

2021 ◽  
pp. 123-130
Author(s):  
Nitesh MONDAL
Keyword(s):  
Design Procedure ◽  
Maximum Flow ◽  
Piston Pump ◽  
Experimental Result ◽  
Axial Piston Pump ◽  
Output Pressure ◽  
Swash Plate ◽  
Variable Displacement ◽  
Axial Piston ◽  
Plate Type

This work presents a simple design procedure of a pressure compensator of a swash plate type variable displacement axial piston pump (VDAPP). The route of the work mainly focuses on static design through balancing the torque given by the pump pistons, rate cylinder and strok- ing cylinder on the swash plate during cut-in (maximum flow) and cut-off (minimum flow) pressure condition of the system with an objective of minimizing the output pressure ripples. The outcome in terms of pressure from the dynamic simulation of the designed compensator with pump has been compare with experimental result obtained from a reference commercial pump has compensator with duel spool. The model has been used for performance prediction for wide variations of the load valve area settings.

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