The Effect of Oil Entrapment in an Axial Piston Pump

1985 ◽  
Vol 107 (4) ◽  
pp. 246-251 ◽  
Author(s):  
S. J. Lin ◽  
A. Akers ◽  
G. Zeiger
Keyword(s):  
Pressure Distribution ◽  
Dynamical Equation ◽  
Control Volume ◽  
Equation Of Motion ◽  
Piston Pump ◽  
Axial Piston Pump ◽  
Angular Rotation ◽  
Instantaneous Pressure ◽  
Discharge Pressure ◽  
Axial Piston

Values of pressure caused by entrapment beneath a valve plate have been calculated. The technique used consists of the solution of the dynamical equation of motion in the piston control volume. Instantaneous and average values of torque have also been deduced from the pressure distribution. Plots have been constructed showing the effect of swashplate angle, pump angular rotation, discharge pressure, and entrapment angle upon instantaneous pressure, torque, and average torque for a typical axial piston pump.

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.

Pressure, Flow, Force, and Torque Between the Barrel and Port Plate in an Axial Piston Pump

2008 ◽  
Vol 130 (1) ◽  
Author(s):  
J. M. Bergada ◽  
J. Watton ◽  
S. Kumar
Keyword(s):  
Pressure Distribution ◽  
Operating Conditions ◽  
Piston Pump ◽  
Axial Piston Pump ◽  
Operating Characteristics ◽  
Double Peak ◽  
Fluctuation Pattern ◽  
Total Magnitude ◽  
Axial Piston ◽  
Insight Into

This paper analyzes the pressure distribution, leakage, force, and torque between the barrel and the port plate of an axial piston pump. A detailed set of new equations is developed, which takes into account important parameters such as tilt, clearance and rotational speed, and timing groove. The pressure distribution is derived for different operating conditions, together with a complementary numerical analysis of the original differential equations, specifically written for this application and used to validate the theoretical solutions. An excellent agreement between the two approaches is shown, allowing an explicit analytical insight into barrel/port plate operating characteristics, including consideration of cavitation. The overall mean force and torques over the barrel are evaluated and show that the torque over the XX axis is much smaller than the torque over the YY axis, as deduced from other nonexplicit simulation approaches. A detailed dynamic analysis is then studied, and it is shown that the torque fluctuation over the YY axis is typically 8% of the torque total magnitude. Of particular novelty is the prediction of a double peak in each torque fluctuation resulting from the more exact modeling of the piston/port plate/timing groove pressure distribution characteristic during motion. A comparison between the temporal torque fluctuation pattern and another work shows a good qualitative agreement. Experimental and analytical results for the present study demonstrate that barrel dynamics do contain a component primarily directed by the torque dynamics.

Dynamic Analysis of an Axial Piston Pump Swashplate Control

1986 ◽  
Vol 200 (1) ◽  
pp. 49-58 ◽  
Author(s):  
G Zeiger ◽  
A Akers
Keyword(s):  
Control Volume ◽  
Damping Ratio ◽  
Low Frequency ◽  
Operating Conditions ◽  
Piston Pump ◽  
State Variables ◽  
Axial Piston Pump ◽  
Basic Parameters ◽  
Experimental Values ◽  
Axial Piston

A mathematical model of an axial piston pump is described which consists of a second-order differential equation of the swashplate motion and two first-order equations describing the flow continuity into the pump discharge chamber and into the swashplate control actuator. The equation of the swashplate angle contains torque components due to operating states. A method is presented by which the average torque can be computed for a pump of given geometry and at any given set of operating conditions. From the calculated average torque, the coefficients of the basic equation can be evaluated; agreement to within 10 per cent of experimental values for torque has been achieved. A state variables analysis of the dynamic behaviour has shown that there are two dominant poles at low frequency and that the damping ratio associated with these poles reduces by approximately one half when the downstream control volume increases by a factor of three, and varies from 0.84 to 0.48 as the pump rotational speed increases from 126 to 209 rad/s. It has been concluded that the assumption of linear variation with the basic parameters, which is a necessary prerequisite for the use of states variables analysis, is justified. The work outlined in this paper represents a step in the design process associated with the optimal control of an axial piston pump.

The Analysis of Cavitation Problems in the Axial Piston Pump

2010 ◽  
Vol 132 (7) ◽  
Author(s):  
Shu Wang
Keyword(s):  
Vapor Pressure ◽  
Control Volume ◽  
Low Pressure ◽  
Valve Plate ◽  
Piston Pump ◽  
Axial Piston Pump ◽  
Axial Piston Pumps ◽  
Design Guide ◽  
Axial Piston ◽  
Plate Geometry

This paper discusses and analyzes the control volume of a piston bore constrained by the valve plate in axial piston pumps. The vacuum within the piston bore caused by the rise volume needs to be compensated by the flow; otherwise, the low pressure may cause the cavitations and aerations. In the research, the valve plate geometry can be optimized by some analytical limitations to prevent the piston pressure below the vapor pressure. The limitations provide the design guide of the timings and overlap areas between valve plate ports and barrel kidneys to consider the cavitations and aerations.

Torque on the Swashplate of an Axial Piston Pump

1985 ◽  
Vol 107 (3) ◽  
pp. 220-226 ◽  
Author(s):  
G. Zeiger ◽  
A. Akers
Keyword(s):  
Equations Of Motion ◽  
Equation Of Motion ◽  
Operating Conditions ◽  
Piston Pump ◽  
Axial Piston Pump ◽  
Geometrical Features ◽  
Mathematical Equations ◽  
Axial Piston ◽  
System Operating ◽  
Methods Of Control

As part of a study involving methods of control of an axial piston pump, it is required to obtain linear or linearized equations of motion of the system’s states. The torque imposed on the plate by the pumping action of the pistons is the most important term in the equation of motion of the swashplate. The torque is a result of a nonlinear and partly discontinuous relationship; this relationship being a function of the geometrical features of the pump and the system operating conditions. Mathematical equations describing swashplate torque are derived from general hydraulic and mechanical considerations given in this paper. This mathematical model can be linearized so that linear parameters for the equation of motion of the swashplate can be obtained. In addition, results of predictions made by the model are presented and compared with some experimental data provided by Sundstrand. An indication is also given as to changes in torque resulting from variation in swashplate angular velocity and timing position of the valve plate.

scholarly journals Novel design of hydrodynamic–magnetic compound support for cylinder block–valve plate in axial piston pump

AIP Advances ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 115221
Author(s):  
Jihai Jiang ◽  
Boran Du ◽  
Jian Zhang ◽  
Geqiang Li
Keyword(s):  
Valve Plate ◽  
Piston Pump ◽  
Cylinder Block ◽  
Axial Piston Pump ◽  
Axial Piston ◽  
Novel Design
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