The Control Torque on the Swash Plate of an Axial-Piston Pump Utilizing Piston-Bore Springs

1999 ◽  
Vol 123 (3) ◽  
pp. 471-478 ◽  
Author(s):  
Noah D. Manring ◽  
Fikreadam A. Damtew
Keyword(s):  
Mechanical Analysis ◽  
Plate Motion ◽  
Cylinder Block ◽  
Normal Operation ◽  
Favorable Result ◽  
Control Torque ◽  
Restoring Force ◽  
Pump Design ◽  
Swash Plate ◽  
Spring Force

This research begins by presenting a nontraditional pump design which utilizes a piston-bore spring. The piston-bore spring is included in this design for the purpose of holding the cylinder block against the valve plate and for forcing the pistons in the negative x-direction. By forcing the pistons in this direction, the piston-bore spring also assists in holding the slippers against the swash plate during the normal operation of the pump. Though these advantages of the design may be readily seen by inspection, it is not obvious how the control torque on the swash plate is effected by the piston-bore spring nor is it obvious how one would go about designing the spring to produce a favorable result. To clarify the benefit of this design, a mechanical analysis is conducted to describe the effect of the spring on the control torque itself. As a result of this analysis, a general equation which describes the swash-plate motion is presented. Within this equation, it may be seen that the spring force provides a restoring force on the swash plate which tends to stabilize the design. The piston-bore spring is also shown to be capable of eliminating the cross-over from a stroke increasing swash-plate torque to a stroke decreasing swash-plate torque. By eliminating this cross over, the backlash in the pump control (which is commonly observed in practice) can be prevented.

Tipping the Cylinder Block of an Axial-Piston Swash-Plate Type Hydrostatic Machine

1997 ◽  
Vol 122 (1) ◽  
pp. 216-221 ◽  
Author(s):  
Noah D. Manring
Keyword(s):  
Control Volume ◽  
Pressure Profile ◽  
Mechanical Analysis ◽  
Design Guidelines ◽  
Design Criterion ◽  
Valve Plate ◽  
Cylinder Block ◽  
Swash Plate ◽  
Axial Piston ◽  
Plate Type

Tipping the cylinder block within an axial-piston swash-plate type hydrostatic machine is a phenomenon that results in a momentary and sometimes permanent failure of the machine since the fluid communication between the cylinder block and the valve plate is instantaneously lost. The efforts of this research are to identify the physical contributors of this phenomenon and to specify certain design guidelines that may be used to prevent the failure of cylinder block tipping. This research begins with the mechanical analysis of the machine and presents a tipping criterion based upon the centroidal location of the force reaction between the cylinder block and the valve plate. This analysis is followed by the derivation of the effective pressurized area within a single piston bore and the cylinder block balance is defined based upon this result. Using standard control volume analysis, the pressure within a single piston bore is examined and it is shown that an approximate pressure profile may be used in place of the more complex representation for this same quantity. Based upon the approximate pressure profile a design criterion is presented which ensures that the pressures within the system never cause the cylinder block to tip. Furthermore, if this criterion is satisfied, it is shown that the worst tipping conditions exist when the system pressures are zero and therefore a criterion governing the design of the cylinder block spring is presented based upon the inertial forces that contribute to the tipping failure. [S0022-0434(00)00901-1]

Advanced Virtual Prototyping of Axial Piston Machines

2016 ◽  
Author(s):  
Rene Chacon ◽  
Monika Ivantysynova
Keyword(s):  
Numerical Models ◽  
Virtual Prototyping ◽  
Valve Plate ◽  
Cylinder Block ◽  
Plate Interface ◽  
Design And Optimization ◽  
Swash Plate ◽  
Axial Piston Machine ◽  
Axial Piston ◽  
Plate Type

This paper explains how a combination of advanced multidomain numerical models can be employed to design an axial piston machine of swash plate type within a virtual prototyping environment. Examples for the design and optimization of the cylinder block/valve plate interface are presented.

Robust Nonlinear Control of a Novel Indexing Valve Plate Pump: Simulation Studies

2002 ◽  
Vol 124 (4) ◽  
pp. 613-616 ◽  
Author(s):  
X. Zhang ◽  
S. S. Nair ◽  
N. D. Manring
Keyword(s):  
Pressure Control ◽  
Plate Motion ◽  
Nonlinear Simulation ◽  
Response Characteristics ◽  
Model Free ◽  
Swash Plate ◽  
Displacement Pump ◽  
Variable Displacement ◽  
Robust Adaptive ◽  
Improved Performance

A robust adaptive pressure control strategy is proposed for a novel indexing variable-displacement pump. In the proposed approach, parametric uncertainties and unmodeled dynamics are identified to the extent possible using a model free learning network and used to decouple the dynamics using physical insights derived from careful reduced order modeling. The swash plate motion control is then carefully designed to provide the desired pressure response characteristics showing improved performance with learning. The proposed control framework and designs are validated using a detailed nonlinear simulation model.

Scaling the Speed Limitations for Axial-Piston Swash-Plate Type Hydrostatic Machines

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
Noah D. Manring ◽  
Viral S. Mehta ◽  
Bryan E. Nelson ◽  
Kevin J. Graf ◽  
Jeff L. Kuehn
Keyword(s):  
Scaling Law ◽  
Simple Rule ◽  
Cylinder Block ◽  
Cube Root ◽  
Industry Data ◽  
Swash Plate ◽  
Axial Piston ◽  
Plate Type ◽  
New Machine

This paper proposes a scaling law for estimating the speed limitations for a family of axial-piston swash-plate type hydrostatic machines. The speed limitations for this machine are considered from three mechanical perspectives: (1) cylinder-block tipping, (2) cylinder-block filling, and (3) slipper-tipping. As shown in the results of this research, each speed limitation is scaled by the inverse of the cube root of the volumetric displacement for the new machine. In other words, small machines are shown to have a higher speed capacity than larger machines. By scaling a baseline machine using the scale laws that are presented here, a new machine may be produced that obeys a simple rule related only to the volumetric displacement of the new machine. Serendipitously, and perhaps most usefully, all three speed limitations obey the same rule! The speed limitations that are derived in this research are compared to existing industry data of currently scaled products and it is shown that the proposed scale laws correspond well with this data.

DYNAMIC LOADS ON THE DRIVE SHAFT BEARINGS OF A SWASH PLATE AXIAL PISTON PUMP WITH CONICAL CYLINDER BLOCK

2004 ◽  
Vol 27 (4) ◽  
pp. 309-318
Author(s):  
M.K. Bahr Khalil ◽  
J.V. Svoboda ◽  
R.B. Bhat
Keyword(s):  
The Body ◽  
Drive Shaft ◽  
Dynamic Loads ◽  
Cylinder Block ◽  
Axial Piston Pump ◽  
Static And Dynamic Characteristics ◽  
Swash Plate ◽  
Variable Displacement ◽  
Heavy Loads ◽  
Axial Piston

Variable displacement swash plate pumps are invariably used under conditions that involve heavy loads with variable flow demands. Swash plate pumps with conical cylinder blocks are now widely used in view of their good static and dynamic characteristics. However, drive shafts of these pumps experience dynamic loads due to the pressure forces transmitted through the body of the conical cylinder block to the supporting bearings. Dynamics of such rotating mechanism are quite interesting and should be considered in the design process of the drive shaft and the supporting bearings. A mathematical model is formulated for a 9-piston swash plate pump with conical cylinder block in order to evaluate the dynamic loads on the drive shaft. Results are presented and discussed.

Thermo-Mechanical Analysis of the Cylinder Head and Cylinder Block - CAE Approach

2013 ◽  
Author(s):  
Chiranjeevi Krishnappa ◽  
Mohan Makana ◽  
Mandar M. Kulkarni
Keyword(s):  
Cylinder Head ◽  
Mechanical Analysis ◽  
Cylinder Block

Surface modification effects on lubricant temperature and floating valve plate motion in an axial piston pump

2019 ◽  
Vol 234 (1) ◽  
pp. 3-17 ◽  
Author(s):  
David Richardson ◽  
Farshid Sadeghi ◽  
Richard G Rateick ◽  
Scott Rowan
Keyword(s):  
Equations Of Motion ◽  
Surface Modifications ◽  
Analytical Investigation ◽  
Operating Conditions ◽  
Valve Plate ◽  
Piston Pump ◽  
Plate Motion ◽  
Cylinder Block ◽  
Axial Piston Pump ◽  
Axial Piston

The objectives of this study were to experimentally measure motion of a floating valve plate and analytically investigate the effects of floating valve plate surface modifications on the lubricant film thickness and temperature distribution. In order to achieve the experimental objectives, a previously developed axial piston pump test rig was instrumented with proximity probes to measure the motion of the valve plate. To achieve the objectives of the analytical investigation, the thermal Reynolds equation augmented with the Jakobsson-Floberg-Olsson (JFO) boundary condition and the energy equation were simultaneously solved to determine the pressure, cavitation regions, and temperature of the lubricant at the valve plate/cylinder block interface. The lubricating pressures were then coupled with the equations of motion of the floating valve plate to develop a dynamic lubrication model. The stiffness and damping coefficients of the floating valve plate system used in the dynamic lubrication model were determined using a parametric study. The elastic deformation of the valve plate was also considered using the influence matrix approach. The experimental and analytical motions of the valve plate were then corroborated and found to be in good agreement. Four- and eight-pocket designs were then added as surface modifications to the floating valve plate in the dynamic lubrication model. The addition of surface modifications on the valve plate resulted in increased minimum film thicknesses and lowered lubricant temperatures at the same operating conditions.

scholarly journals Friction and wear analysis of the external return spherical bearing pair of axial piston pump/motor

2020 ◽  
Vol 21 (1) ◽  
pp. 104 ◽  
Author(s):  
Haishun Deng ◽  
Cong Hu ◽  
Qingchun Wang ◽  
Lei Wang ◽  
Chuanli Wang
Keyword(s):  
Contact Point ◽  
Power Fluctuation ◽  
Rotating Speed ◽  
Friction Power ◽  
Swash Plate ◽  
Discrete Contact ◽  
Spring Force ◽  
Spherical Bearing ◽  
Pump Shaft ◽  
Fluctuation Amplitude

By discretizing the contact area between the external retainer plate and the external spherical hinge, a mathematical model for the force relation of an arbitrary contact point in the external return spherical bearing pair was established and a mathematical expression for the friction power of the external return spherical bearing pair was deduced. The influences of the slant inclination of the external swash plate, pump shaft rotating speed, eccentricity, spring force and number of discrete contact points on the friction power were also analysed. The results show that the power fluctuation amplitude of the discrete contact point in the external return spherical bearing pair increases with increasing slant inclination of the external swash plate, pump shaft rotating speed and spring force; the total friction power was found to increase linearly. However, the power fluctuation amplitude of the discrete contact point in the external return spherical bearing pair was found to decrease with increasing eccentricity, with the total friction power decreasing nonlinearly until reaching a certain value. The distribution shape of the friction power of the discrete contact point is only affected by eccentricity. If the eccentricity is large, the friction power of the discrete point presents a double-peak distribution, whereas if it is small, a multiple-peak distribution is observed.

Helicopter Swashplate Design and Analysis Using Semi Compliant Mechanism

2018 ◽  
Author(s):  
Ayse Tekes ◽  
Adeel Khalid ◽  
Niko Giannakakos ◽  
Alexander Bryant
Keyword(s):  
Compliant Mechanism ◽  
High Amplitude ◽  
Plate Motion ◽  
Swash Plate ◽  
Directional Control ◽  
Single Piece ◽  
Model Helicopter ◽  
The Individual ◽  
And Control ◽  
The Mathematical Model

The swashplate of a model helicopter consists of stationary and rotating plates separated by ball bearings. This mechanism enables the swashplate to tilt in all directions and move vertically as one unit. The lower stationary plate is mounted on the main rotor mast and connected to the cyclic and collective controls by a series of pushrods. There are similar pushrods known as pitch links connected to the upper rotating plate. These pitch links are connected to the pitch horns and control the pitch of individual blades. In this study, the pitch links of the model helicopter are replaced by a semi compliant mechanism. This mechanism is directly connected to the pitch horns to control the pitch of the individual blades. The actuation of the bars can be achieved by using high torque stepper or servo motors. These precise low and high amplitude outputs are specifically required for the cyclic and collective controls of the helicopter swashplate. The compliant swashplate mechanism can be fabricated as a single piece using an injection molding technique or by 3D printing. The mechanism is modeled by two similar vector loops in two different planes. The mathematical model of the plate motion and the forces on the mechanism links are developed and simulated using MATLAB and Simulink, and initial results are discussed in this paper. This mechanism would be applied to the helicopter directional control where the plate in the pitch-roll mechanism would serve as the swash plate of the helicopter.

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