Principle of Oil Film Test on Port Pair of Axial Piston Pump and Control Characteristics

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.

Download Full-text

Novel Piston Pressure Carryover for Dynamic Analysis and Designs of the Axial Piston Pump

Journal of Dynamic Systems Measurement and Control ◽

10.1115/1.4023065 ◽

2012 ◽

Vol 135 (2) ◽

Cited By ~ 3

Author(s):

Shu Wang

Keyword(s):

Piston Pump ◽

Axial Piston Pump ◽

Pump Performance ◽

Axial Piston Pumps ◽

Bottom Dead Center ◽

Pump Pressure ◽

Definition Of ◽

And Control ◽

Axial Piston ◽

The Relationship

The timing definition of valve plates is one of the most complex topics in the piston pump designs because it affects many pump characteristics (such as efficiency, swashplate stroking, stabilities, noise, etc.). In the study, the pressure carryover is introduced and defined as the average angular positions to locate piston pressure transitions from the top dead center (TDC) or bottom dead center (BDC) in the piston pump. Pressure carryover presents the overall outcome of the pressure transitions within piston bores. The new pressure carryover definition is derived by the timing angles and other geometrics of valve plates that is an approximation of the practical pressure transitions. The pressure carryover also determines the containment forces and moments on the swashplate produced by the pumping pistons. The relationship between the pressure carryover angle and the containment moment has been developed and analyzed in the study. The amplitudes and frequencies of the forces and moments can be changed by varying the pressure carryover angle that produce different tonalities and control efforts for the swashplate type axial-piston pumps. Therefore, the pressure carryover is the most important and straightforward connection between pump dynamics and valve plate designs. In order to optimize the pump performance, the piston pressure carryover might be investigated thoroughly for the pump and its controller designs.

Download Full-text

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

Industrial Lubrication and Tribology ◽

10.1108/ilt-04-2017-0102 ◽

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.

Download Full-text

Analysis and simulation of the property of oil film of the slipper in axial piston pump

Proceedings of 2011 International Conference on Electronic & Mechanical Engineering and Information Technology ◽

10.1109/emeit.2011.6023346 ◽

2011 ◽

Cited By ~ 2

Author(s):

Yi Sun ◽

Jihai-Jiang ◽

Yu Zhou

Keyword(s):

Piston Pump ◽

Axial Piston Pump ◽

Oil Film ◽

Axial Piston

Download Full-text

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

Proceedings of the Institution of Mechanical Engineers Part J Journal of Engineering Tribology ◽

10.1177/1350650119872888 ◽

2019 ◽

Vol 234 (4) ◽

pp. 515-527 ◽

Cited By ~ 1

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.

Download Full-text

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

Processes ◽

10.3390/pr8010068 ◽

2020 ◽

Vol 8 (1) ◽

pp. 68 ◽

Cited By ~ 1

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.

Download Full-text

Optimization and Influence of Micro-Chamfering on Oil Film Lubrication Characteristics of Slipper/Swashplate Interface within Axial Piston Pump

Energies ◽

10.3390/en14071961 ◽

2021 ◽

Vol 14 (7) ◽

pp. 1961

Author(s):

Jihai Jiang ◽

Zebo Wang

Keyword(s):

Numerical Model ◽

Film Thickness ◽

Power Loss ◽

Piston Pump ◽

Total Power ◽

Axial Piston Pump ◽

Oil Film ◽

Friction Power ◽

Lubrication Characteristics ◽

Axial Piston

The overturning and eccentric abrasion of the slipper worsens the lubrication characteristics and increases the friction power loss and kinetic energy consumption of the slipper/swashplate interface to reduce the axial piston pump efficiency. A coupling lubrication numerical model and algorithm and a micro-chamfering structure are developed and proposed to predict more precisely and improve the lubrication characteristics of the slipper/swashplate interface. The simulation results reveal that the slipper without micro-chamfering overturns and contacts with the swashplate, while the one with micro-chamfering forms a certain oil film thickness to prevent this contact effectively. The minimum total power loss of the slipper/swashplate interface has to be effectively ensured under the worst working conditions, such as the high pressure, the low speed, the maximum swashplate inclination angle and the minimum house pressure. The optimal micro-chamfering width and depth are 1.2 mm and 3.5 μm or C1.2-3.5, the simulation average oil film thickness of which is approximately equal to the optimal analytical value. The experimental friction power loss of the slipper/swashplate interface is basically consistent with the simulation one, confirming the correctness and effectiveness of the coupling lubrication numerical model, and the optimization method and providing the further design direction of axial piston pumps.

Download Full-text

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

Mathematical Problems in Engineering ◽

10.1155/2018/7395727 ◽

2018 ◽

Vol 2018 ◽

pp. 1-9 ◽

Cited By ~ 2

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.

Download Full-text