scholarly journals Study on Oil Film Characteristics of Piston-Cylinder Pair of Ultra-High Pressure Axial Piston Pump

Processes ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 68 ◽  
Author(s):  
Jin Zhang ◽  
Baolei Liu ◽  
Ruiqi LÜ ◽  
Qifan Yang ◽  
Qimei Dai
Keyword(s):  
High Pressure ◽  
Piston Pump ◽  
Axial Piston Pump ◽  
Film Pressure ◽  
Oil Film ◽  
Ultra High Pressure ◽  
Piston Cylinder ◽  
The Mathematical Model ◽  
Axial Piston ◽  
Oil Film Pressure

The piston-cylinder pair is the key friction pairs in the piston pump. Its performance determines the volume efficiency of piston pump. With the increase of load pressure, the leakage at the clearance of piston-cylinder pair will also increase. In order to reduce leakage, the clearance of the piston-cylinder pair of the ultra-high pressure piston pump is smaller than that of the medium-high pressure piston pump. In order to explore whether the piston will stuck in the narrow gap, it is necessary to study the oil film characteristics of the piston-cylinder pair under the condition of ultra-high pressure, so as to provide a theoretical basis for the optimal design of the piston-cylinder pair of ultra-high pressure axial piston pump. In this paper, an ultra-high pressure axial piston pump is taken as the research object, and its structural characteristics are analyzed. The mathematical model of the oil film thickness of the piston-cylinder pair is established by using the cosine theorem in the cross section of the piston. The finite volume method is used to discretize the Reynolds equation of the oil film of the piston-cylinder pair, and the over relaxation iteration method is used to solve the discrete equations, and the mathematical model of the oil film pressure of the piston-cylinder pair is obtained. The mathematical model of oil film thickness and pressure field of piston-cylinder pair is solved by programming. The dynamic change process of oil film thickness and pressure field of the plunger pair of the ultra-high pressure axial piston pump under the load of 20 MPa and 70 MPa is obtained. Under the two conditions, the thinnest area of the oil film reaches 3 μm and 2 μm dangerous area respectively; the oil film pressure reaches 20 MPa and 70 MPa respectively when the swashplate rotates 10° and continues to increase with the increase of swashplate rotation angle. When the rotation angle reaches 90°, the oil film pressure also reaches the maximum value, but there is no pressure spike phenomenon. The oil film pressure characteristics of ultra-high pressure axial piston pump under conventional and ultra-high pressure conditions were obtained by modification and experimentation.

Study on the Influence of Deformation of the Slipper of Axial Piston Pump under High Pressure on Oil Film Structure

2014 ◽  
Vol 900 ◽  
pp. 734-737 ◽  
Author(s):  
Huai Chao Wu ◽  
Yun Liu Yu
Keyword(s):  
High Pressure ◽  
Film Structure ◽  
Piston Pump ◽  
Axial Piston Pump ◽  
Working Pressure ◽  
Element Analysis ◽  
Oil Film ◽  
The Finite Element Analysis ◽  
Order Of Magnitude ◽  
Axial Piston

The stress and strain of the slipper of 35 MPa high pressure axial piston pump are analyzed by the finite element analysis method, and the following facts are revealed: in spite of the fact that the slipper can satisfy the use requirement in the aspect of stress, whereas, in the aspect of strain, the deformation of the bottom of the slipper increases with the pressure increase, and the deformation of the slipper has reached the order of magnitude of the oil film thickness under 35 MPa working pressure. Therefore, when the slipper pair of 35 MPa high pressure axial piston pump is designed and its oil film performances are studied, the influence of deformation of the slipper on the oil film structure must be considered comprehensively. The results of this study can provide some guides for developing 35 MPa high pressure axial piston pump.

scholarly journals Research on thermal-fluid-structure coupling of valve plate pair in an axial piston pump with high pressure and high speed

2018 ◽  
Vol 70 (6) ◽  
pp. 1137-1144
Author(s):  
Zhanling Ji
Keyword(s):  
High Pressure ◽  
High Speed ◽  
Valve Plate ◽  
Piston Pump ◽  
Axial Piston Pump ◽  
Fluid Structure ◽  
Content Type ◽  
Oil Film ◽  
Field Coupling ◽  
Axial Piston

Purpose High pressure and high speed of the axial piston pump can improve its power density, but they also deteriorate the thermal-fluid-structure coupling effect of the friction pairs. This paper aims to reveal the coupling mechanism of the pump, for example, valve plate pair, by carrying out research on multi-physics field coupling. Design/methodology/approach Considering the influences of temperature on material properties and thermal fluid on structure, the thermal-fluid elastic mechanics model is established. A complete set of fast and effective thermal-fluid-structure coupling method is presented, by which the numerical analysis is conducted for the valve plate pair. Findings According to calculations, it is revealed that the temperature and pressure evolution laws of oil film with time, the pressure distribution law of the fluid, stress and displacement distribution laws of the solid in the valve plate pair. In addition, the forming history of the wedge-shaped oil film and mating clearance change law with rotational speed and outlet pressure in the valve plate pair are presented. Originality/value For an axial piston pump operating under high speed, high pressure and wide temperature range, the multi-physics field coupling analysis is an indispensable means and method. This paper provides theoretical evidence for the development of the pump and lays a solid foundation for the research of the same kind of problem.

Wear behavior of friction pairs of different materials for ultra-high-pressure axial piston pump

2018 ◽  
Vol 233 (5) ◽  
pp. 945-953 ◽  
Author(s):  
Jin Zhang ◽  
Xiaogang Qiu ◽  
Xuezhi Gong ◽  
Xiangdong Kong
Keyword(s):  
High Pressure ◽  
Friction Coefficient ◽  
Surface Morphology ◽  
Ceramic Materials ◽  
Piston Pump ◽  
Wear Testing ◽  
Axial Piston Pump ◽  
Ultra High Pressure ◽  
Two Samples ◽  
Axial Piston

This paper evaluates the wear of two different materials (ceramic and 30Cr2MoVA) of friction pairs of ultra-high-pressure axial piston by means of experimental investigations. Face sliding wear test was carried out on wear testing machine to analyze the coefficient of friction during boundary friction. Then wear amount of the sample is obtained by weighing with the electronic balance. The change of the surface morphology was observed by a laser confocal microscope. By comparing the friction coefficient, wear amount, surface morphology, temperature change, and roughness of the two samples, it has been found that ceramic materials have lower friction coefficient, better wear resistance, and less oil temperature rise than 30Cr2MoVA material. By the above research results it was found that ceramic materials perform better than 30Cr2MoVA, which provides the foundation for further study of the friction pair of the ultra-high-pressure axial piston pump.

Research on lubrication mechanism with fluid–solid coupling of port plate pair in swash plate axial piston pump

2019 ◽  
Vol 234 (4) ◽  
pp. 515-527 ◽  
Author(s):  
Zhaoqiang Wang ◽  
Yanfei Xu ◽  
Shan Hu ◽  
Hong Ji ◽  
Jian Yang
Keyword(s):  
High Pressure ◽  
Structural Parameters ◽  
Valve Plate ◽  
Piston Pump ◽  
Fluid Viscosity ◽  
Pressure Side ◽  
Axial Piston Pump ◽  
Oil Film ◽  
Swash Plate ◽  
Axial Piston

When a swash plate axial piston pump operates under high-pressure conditions, the valve plate will undergo warping deformation. Based on the theory of elastic fluid dynamic lubrication, this work establishes a fluid–solid coupling model of a swash plate axial piston pump and solves the governing equations of the lubrication with respect to the port plate pair. Cylinder speed, cylinder angle, fluid viscosity, oil film thickness, seal belt width, and structural parameters are also considered to observe their influence on the valve plate warpage deformation with the swash plate axial piston pump. The results show that the deformation cloud of the valve plate on the axial piston pump is symmetrical, with the axis line of the waist groove as the axis. The deformation of the outer seal zone on the high-pressure side of the valve plate is the largest, and the deformation of the outer seal zone on the low-pressure side of the valve plate is the smallest. Under the same conditions, the material and structure of the valve plate affect the thickness and shape of the oil film. This study provides a theoretical basis for the high pressure of the swash plate axial piston pump.

scholarly journals Study on Leaking Characteristics of Port Plate Pair in Primary Three-Row Axial Piston Pump/Motor

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Haishun Deng ◽  
Qingchun Wang ◽  
Peng Dai ◽  
Yongkang Yang
Keyword(s):  
High Pressure ◽  
Structural Design ◽  
Common Type ◽  
Piston Pump ◽  
Central Angle ◽  
Axial Piston Pump ◽  
Oil Film ◽  
Reasonable Range ◽  
Axial Piston ◽  
Volume Efficiency

In order to investigate the leaking characteristics of the port plate pair in primary three-row axial piston pump/motor, the present paper deducts two equations about the leakage of oil film, analyzes the effect of such parameters as oil film thickness, sealing tape width, and central angle of waist-like slot on the leakage, and arrives at the following conclusions: for the primary three-row axial piston pump/motor, the angle of heel on cylinder increases the leakage of port plat pair, but high-pressure areas on its both sides with similar displacement weaken the effect of the scope and direction of angle of heel on the leakage and help to stabilize the port plat pair’s leakage and maintain the fluid lubrication; widening the sealing tape in a reasonable range can effectively bring down the leakage and raise the volume efficiency; in case of any change in the central angle of waist-like slot, the leakage of primary three-row axial piston pump/motor appears to be more stable than common type, which is more favorable for maintaining the fluid lubrication in the port plat pair. This study can shed some light on the structural design of the primary three-row axial piston pump/motor.

Calculation Method of Lubricant Film Pressure Distribution of Axial Piston Pump Slippers

2013 ◽  
Vol 328 ◽  
pp. 629-633
Author(s):  
Ya Jun Wang
Keyword(s):  
High Pressure ◽  
Pressure Distribution ◽  
Mass Conservation ◽  
Piston Pump ◽  
Axial Piston Pump ◽  
Shearing Flow ◽  
Pump Speed ◽  
Pressure Area ◽  
The Difference ◽  
Axial Piston

A method is implemented to get the pressure distribution of the axial piston pump slipper. Slipper was seen as translating thrust bearing, taking slipper tilt and spin in account, based on finite volume method, hydrodynamic and hydrostatic pressure has been calculated by using the mass conservation principle. For a representative element volume, the difference flow was averaged by the difference flow between the tilting planes, and the shearing flow by slipper translating was averaged by the shearing flow between the tilting planes. The numerical calculating result based two liquid resistance assume was compared, the results showed that two methods have got the same pressure distribution schematics, and the high pressure area locates at the slipper titling direction, but for the pressure values at high pressure area, the second method is slightly higher than the first method, and that the higher pump speed were, the higher the pressure values, and at the same pump speed, the slipper spin speed affects slightly the pressure, and at the lower pump speed, the lubricant pressure tends to the hydrostatic lubrication.

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