Kinematic Analysis of a Swash-Plate Controlled Variable Displacement Axial-Piston Pump With a Conical Barrel Assembly

2009 ◽  
Vol 132 (1) ◽  
Author(s):  
Zhiru Shi ◽  
Gordon Parker ◽  
Jonathan Granstrom
Keyword(s):  
High Pressure ◽  
Frequency Analysis ◽  
Flow Rate ◽  
Piston Pump ◽  
Flow Ripple ◽  
Swash Plate ◽  
Piston Displacement ◽  
Output Flow ◽  
Variable Displacement ◽  
Axial Piston

Variable displacement, swash-plate controlled, axial-piston pumps are widely used in applications that require high pressure and variable flow rates. The pump consists of a rotating barrel assembly that houses several pistons in a circular array. A swash-plate is used to control the displacement of the pistons to adjust the output flow of hydraulic fluid. As the barrel rotates, the pistons slide along the angled swash-plate and draw oil from the supply and then discharge oil into the high pressure circuit. This results in an almost constant output flow rate. This paper analyzes the kinematics of a pump based on its geometry dependent characteristics. The analysis assumes an idealized case in which there is no oil leakage and the fluid is considered to be incompressible. It is revealed through the analysis that the piston displacement and the pump output flow are slightly increased by using a conical barrel. Instantaneous and mean flow rate equations are used to describe the output flow characteristics and flow ripple effect. The output flow rate ripple profile is found to be a function of both swash-plate angle and the conical barrel angle. A term defined as the flow rate uniformity coefficient is used to better quantify the flow ripple phenomenon. A frequency analysis is performed on the output flow rate and an additional order is found to be present when using a conical barrel pump versus one with a cylindrical barrel when the pumps have an odd number of pistons. Conical barrel piston pumps are found to have a slight increase in piston displacement, velocity, and acceleration relative to the rotating barrel frame of reference over a pump with a cylindrical barrel. This translates into an increase in the output flow rate for a conical piston pump under the same operating conditions. The conical barrel is also found to have a reduction in the rotational inertia allowing for faster angular acceleration. The presence of an extra order from a frequency analysis for a conical pump with an odd number of pistons has the potential to cause unwanted noise or vibration to the structure or components attached to the pump.

The influence of dynamic swash plate vibration on outlet flow ripple in constant power variable-displacement piston pump

2019 ◽  
Vol 233 (14) ◽  
pp. 4914-4933 ◽  
Author(s):  
Yang Pan ◽  
Yibo Li ◽  
Dedong Liang
Keyword(s):  
Theoretical Model ◽  
Piston Pump ◽  
Plate Vibration ◽  
Axial Piston Pump ◽  
Constant Power ◽  
Flow Ripple ◽  
Swash Plate ◽  
Variable Displacement ◽  
Outlet Flow ◽  
Axial Piston

The vibration of a swash plate is caused by the piston forces and the control actuator acting on the swash plate. An earlier study of the outlet flow ripple of variable-displacement axial piston pumps assumed a fixed swash plate angle; it ignored the influence of swash plate vibration on the outlet flow ripple of the axial piston pump. In this work, a theoretical model of the outlet flow ripple and pressure pulsation was established in a constant power variable-displacement piston pump. The vibration of swash plate, flow leakage, and valve dynamic characteristics are considered in the theoretical model. The computational results of the theoretical model at different external load pressures are verified by comparison with experimental results. The vibration of the swash plate is strongly influenced by both the piston chamber pressure variation and the control actuator mechanism. The study proved the influence of the swash plate vibration on the outlet flow ripple and the pressure pulsation of an axial piston pump. Compared to the case of a fixed swash plate angle, accounting for swash plate vibration is much more suitable for the accurate determination of the outlet flow ripple and pressure pulsation of an axial piston pump. It is also shown that the vibration of the swash plate affects the valve plate design. Accordingly, valve plate optimization based on the theoretical model of the outlet flow ripple was also studied in this work. The amplitude of the instantaneous outlet flow ripple was considered as the optimization objective function. Finally, the optimized design parameters for a constant power variable-displacement swash plate axial piston pump were evaluated.

Theoretical and Simulation Investigations on Flow Ripple Reduction of Axial Piston Pumps Using Nonuniform Distribution of Pistons

2020 ◽  
Vol 143 (4) ◽  
Author(s):  
Fei Lyu ◽  
Shaogan Ye ◽  
Junhui Zhang ◽  
Bing Xu ◽  
Weidi Huang ◽  
...  
Keyword(s):  
Flow Rate ◽  
Optimization Design ◽  
Nonuniform Distribution ◽  
Piston Pump ◽  
Axial Piston Pump ◽  
Flow Ripple ◽  
Distribution Rule ◽  
Dynamic Simulation Model ◽  
Ripple Reduction ◽  
Axial Piston

Abstract The output flow ripple of the axial piston pump is one of the excitation sources for the hydraulic system vibration. The amplitudes of its specific harmonics must be reduced to avoid the resonance with the hydraulic pipeline. In this paper, a method on the nonuniform distribution of the pistons is put forward to adjust the flow ripple. The deflection angles of the pistons are used to describe the distribution rule. The distribution rule is imported to the Fourier expansion of the flow rate of each single-piston chamber, and then every single flow rate is superposed to obtain the Fourier coefficient of total flow rate that becomes the function of deflection angles. After this, objective optimization design is carried out to reduce the amplitudes of specific harmonics. Finally, the dynamic simulation model of the nonuniformly distributed axial piston pump is established to verify the effects of objective optimization. The results show that the amplitude of the ninth harmonic of the flow ripple can be reduced by about 40%, and the reductions are about 99% for the 18th and 27th harmonic.

The Influence of Cross Angle on the Flow Ripple of Axial Piston Pumps by CFD Simulation

2012 ◽  
Vol 220-223 ◽  
pp. 1675-1678 ◽  
Author(s):  
Xiu Ye Wei ◽  
Hai Yan Wang
Keyword(s):  
Noise Reduction ◽  
Cfd Simulation ◽  
Rotation Angle ◽  
Piston Pump ◽  
Flow Pulsation ◽  
Flow Ripple ◽  
Axial Piston Pumps ◽  
Swash Plate ◽  
The Cross ◽  
Axial Piston

This paper studies the flow pulsation of axial piston pumps of different cross angles based on CFD simulation. The swash-plate cross angle of piston pump affects the piston pump outlet flow pulsation by changing the contraction amount of the plunger in the valve plate transition zone. First, we established the flow pulsation model with swash plate cross angle based on the noise reduction principle of the swash plate cross angle, and studied the influence of cross angle of different rotation angels on the flow pulsation based on CFD simulation. The conclusion is that the maximum and minimum peak of the flow pulsation decreased when the rotation angle of the cross angle is greater than 1 °; the maximum and minimum peak of the flow pulsation increased when the rotation angle of the cross angle is less than -1 °; a good noise reduction can be got when the piston pump cross angle rotates 1°.

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.

Kinematic Analysis of Swash Plate Axial Piston Pump Based on Adams Simulation

2015 ◽  
Vol 741 ◽  
pp. 517-520 ◽  
Author(s):  
Hong Chuan Deng ◽  
Yu Zhang ◽  
Hai Sheng Qian
Keyword(s):  
High Pressure ◽  
High Speed ◽  
Low Cost ◽  
Piston Pump ◽  
Pump Efficiency ◽  
Axial Piston Pump ◽  
Compact Structure ◽  
Swash Plate ◽  
Radial Pump ◽  
Axial Piston

The swash plate axial piston pump is a main part in liquid press system.It is a positive displacement pump which rely on the change of the plunger cavity content to realize oil absorption or discharge of oil by the reciprocating movement of the plunger in the plunger cavity. Plunger, the slippery boots, oil pan, cylinder body are important parts of the swash plate axial piston pump. Sliding boots is one of commonly used by high-pressure plunger pump form, it can meet the needs of the high pressure high speed;the oil distribution plate and cylinder directly affect of the pump efficiency and life span[1]. Because the swash plate axial piston pump has the advantages of compact structure, fewer parts, good manufacture ability, low cost, small volume, light weight, than the radial pump has the advantages of simple structure, easy to realize step less variable and convenient maintenance, it has been widely used in the industrial production.

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