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

2012 ◽  
Vol 135 (2) ◽  
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.

Improving the Volumetric Efficiency of the Axial Piston Pump

2012 ◽  
Vol 134 (11) ◽  
Author(s):  
Shu Wang
Keyword(s):  
Operating Conditions ◽  
Volumetric Efficiency ◽  
Valve Plate ◽  
Piston Pump ◽  
Efficient Design ◽  
Axial Piston Pumps ◽  
Definition Of ◽  
Engineering Practices ◽  
First Time ◽  
Axial Piston

The volumetric efficiency is one of the most important aspects of system performance in the design of axial piston pumps. From the standpoint of engineering practices, the geometric complexities of the valve plate (VP) and its multiple interactions with pump dynamics pose difficult obstacles for optimization of the design. This research uses the significant concept of pressure carryover to develop the mathematical relationship between the geometry of the valve plate and the volumetric efficiency of the piston pump. For the first time, the resulting expression presents the theoretical considerations of the fluid operating conditions, the efficiency of axial piston pumps, and the valve plate designs. New terminology, such as discrepancy of pressure carryover (DPC) and carryover cross-porting (CoCp), is introduced to explain the fundamental principles. The important results derived from this study can provide clear recommendations for the definition of the geometries required to achieve an efficient design, especially for the valve plate timings. The theoretical results are validated by simulations and experiments conducted by testing multiple valve plates under various operating conditions.

The Slipping Shoe Motion Trajectory Analysis and Simulation of Spherical Swashplate Type Axial Piston Pump

2011 ◽  
Vol 301-303 ◽  
pp. 943-948 ◽  
Author(s):  
Yong Qin Chen ◽  
Jian Jun Chen ◽  
San Mai Su
Keyword(s):  
Trajectory Analysis ◽  
Piston Pump ◽  
Motion Trajectory ◽  
Axial Piston Pump ◽  
Final Size ◽  
Key Points ◽  
Current Calculation ◽  
Axial Piston ◽  
The Relationship ◽  
Trajectory Equation

Spherical swashplate type axial piston pump slipping shoe hole shape and reasonable position design is key points for pump working. Current calculation method which adapted average parameters as final size is not accurate in theory. In this paper ,according to the relationship between geometry and motion of piston pump, coordinate transformation is used three times to deduce motion trajectory equation,and drive motion trajectory curve. The method discussed is precise ，it can be used to provide reference for slipping shoe hole design.

Profiling the Discharge Channel Flow Part of Axial Piston Pump

2019 ◽  
pp. 53-64
Author(s):  
N.A. Belov ◽  
O.F. Nikitin
Keyword(s):  
Discharge Channel ◽  
Three Dimensional ◽  
Piston Pump ◽  
Working Fluid ◽  
Dynamic Parameters ◽  
Axial Piston Pump ◽  
Three Dimensional Model ◽  
Output Section ◽  
Axial Piston Pumps ◽  
Axial Piston

The article considers the flow of the working fluid in the discharge channel of the axial piston pump with end distribution. Geometric region shapes of the channels, currently used in axial piston pumps, negatively affecting the dynamic parameters of the flow flowing through it, are determined by numerical simulation. The configuration of the channel cavity allowing a more uniform distribution of dynamic parameters over the volume of the fluid flow is proposed. The optimal ratio between the reference dimensions adopted for constructing a three-dimensional model of the channel was determined based on the study of the dependence of the power factor value, the amount of movement in the output section vs the shape of the channel. Energy loss due to flowing the working fluid through the channel is reduced. The resulting force effect on the discharge pipe and other elements connected to the pump is reduced and the vibroacoustic characteristics of the pump unit are improved.

scholarly journals An Empirical Model for the Churning Losses Prediction of Fluid Flow Analysis in Axial Piston Pumps

Micromachines ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 398
Author(s):  
Ying Li ◽  
Xing Chen ◽  
Hao Luo ◽  
Jin Zhang
Keyword(s):  
Power Density ◽  
High Speed ◽  
Flow Analysis ◽  
Piston Pump ◽  
Cylinder Block ◽  
Axial Piston Pump ◽  
Axial Piston Pumps ◽  
Wide Range ◽  
Fluid Flow Analysis ◽  
Axial Piston

The manufacturing development of axial piston pumps usually takes the trend of high speed and miniaturization, and increases power density. Axial piston pumps are usually characterized as high speed to improve the power density; thus, high-speed churning losses caused by the internal rotating components stirring the oil can increase significantly. In order to improve the efficiency, more attention should be given to the churning losses in axial piston pumps, especially in high-speed conditions. Using the method of least-squares curve fitting, this paper establishes a series of formulas based on the churning losses test rig over a wide range of speeds, which enable accurate predictions of churning losses on the cylinder block and pistons. The reduction coefficient of flow resistance of multi-pistons as calculated. The new churning losses formula devoted to the cylinder block and rotating pistons was validated by comparison with experimental evidence in different geometries of axial piston pumps. According to the prediction model of churning losses, some valuable guidance methods are proposed to reduce the energy losses of the axial piston pump, which are the theoretical support for the miniaturization of axial piston pump manufacturing.

Modelling a Variable Displacement Axial Piston Pump in a Multibody Simulation Environment

2006 ◽  
Vol 129 (4) ◽  
pp. 456-468 ◽  
Author(s):  
Alessandro Roccatello ◽  
Salvatore Mancò ◽  
Nicola Nervegna
Keyword(s):  
Power Systems ◽  
Three Dimensional ◽  
Fluid Power ◽  
Piston Pump ◽  
Axial Piston Pump ◽  
Axial Piston Pumps ◽  
Variable Displacement ◽  
Complex Fluid ◽  
Fluid Power Systems ◽  
Axial Piston

Analysis of a variable displacement axial piston pump, as in other complex fluid power and mechanical systems, requires appropriate insight into three multidisciplinary domains, i.e., hydraulics, mechanics and tribology. In recent years, at FPRL, modelling of axial piston pumps has evolved in AMESim (one-dimensional code) where a three-dimensional mechanical approach has required generation of proprietary libraries leading to the evaluation of internal forces/reactions in all pump subsystems. Tribologic aspects in axial piston pumps modelling are also being investigated but AMESim, in this respect, does not appear as the appropriate computational environment. Consequently, a new approach has been initiated grounded on MSC.ADAMS. In this perspective, the paper details how the model has been developed through proprietary macros that automatically originate all pump subsystems parametrically and further apply required constraints and forces (springs, contacts and pressure forces). The ADAMS environment has also been selected due to co-simulation capabilities with AMESim. Accordingly, the paper elucidates how the entire modelling has been construed where hydraulics is managed in AMESim while ADAMS takes care of mechanics. A comparison between simulated and experimental steady-state characteristics of the axial pump is also presented. As such this paper indicates an innovative methodology for the analysis of complex fluid power systems in the hope that, eventually, tribology will also fit into the scene.

Improving accuracy of cavitation severity recognition in axial piston pumps by denoising time-frequency images

2022 ◽  
Author(s):  
Qun Chao ◽  
Xiaoliang Wei ◽  
Junbo Lei ◽  
Jianfeng Tao ◽  
Cheng-Liang Liu
Keyword(s):  
High Speed ◽  
Diagnostic Performance ◽  
Vibration Signal ◽  
Piston Pump ◽  
Noisy Environment ◽  
Axial Piston Pump ◽  
Denoising Method ◽  
Time Frequency ◽  
Axial Piston Pumps ◽  
Axial Piston

Abstract Vibration signal is a good indicator of cavitation in axial piston pumps. Some vibration-based machine learning methods have been developed for recognizing the pump cavitation. However, their fault diagnostic performance is often unsatisfactory in industrial applications due to the sensitivity of the vibration signal to noise. In this paper, we presented an intelligent method to recognize the cavitation severity of an axial piston pump under noisy environment. First, we adopted short-time Fourier transformation to convert the raw vibration data into spectrograms that acted as input images of a modified LeNet-5 convolutional neural network (CNN). Second, we proposed a denoising method for the converted spectrograms based on frequency spectrum characteristics. Finally, we verified the proposed method on the dataset from a test rig of high-speed axial piston pump. The experimental results indicate that the denoising method significantly improves the diagnostic performance of the CNN model under noisy environment. For example, the accuracy rate of the cavitation recognition increases from 0.52 to 0.92 at SNR of 4 dB by the denoising method.

Robust Electric Load Sensing Applied to an Open Circuit Axial Piston Pump

2006 ◽  
Author(s):  
Michael Rygaard Hansen ◽  
Torben Ole Andersen ◽  
Henrik Clemmensen Pedersen
Keyword(s):  
Mechanical Load ◽  
Pressure Control ◽  
Open Circuit ◽  
Piston Pump ◽  
Physical Parameters ◽  
Axial Piston Pump ◽  
System Utilization ◽  
Load Sensing ◽  
Pump Pressure ◽  
Axial Piston

Electronic load sensing (ELS) systems have long been expected to start replacing traditional (hydro-mechanical) load sensing (LS) systems, which today are the standard on most medium and high-end mobile hydraulic applications. The reason for this being the potentials that ELS brings relative to traditional LS-systems, in terms of better control and system utilization possibilities, combined with the increased acceptance and use of electronic sensors in mobile hydraulic machinery. The current work is to evaluate the suitability of an ELS concept applied to a Sauer Danfoss Series 45 H-frame open circuit axial piston pump. Emphasis is on performance robustness with respect to both variations in internal physical parameters of the pump as well as the type of application dependent load which the pump is expected to drive. The pressure control is established by means of cascade control utilizing four control loops with the outer being the pump pressure and then, in succession, the swash plate rotation, the spool position and the voice coil current. The proposed controller has been implemented experimentally and verified.

Predicting axial piston pump performance using neural networks

1999 ◽  
Vol 34 (8) ◽  
pp. 1211-1226 ◽  
Author(s):  
Mansour A Karkoub ◽  
Osama E Gad ◽  
Mahmoud G Rabie
Keyword(s):  
Neural Networks ◽  
Piston Pump ◽  
Axial Piston Pump ◽  
Pump Performance ◽  
Axial Piston
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