Numerical analysis of the lubricating gap between the gear shaft and the journal bearing in water hydraulic internal gear pumps

2017 ◽  
Vol 232 (12) ◽  
pp. 2297-2314 ◽  
Author(s):  
Ruilong Du ◽  
Yinglong Chen ◽  
Hua Zhou
Keyword(s):  
Journal Bearing ◽  
Radial Force ◽  
Gear Pump ◽  
Film Pressure ◽  
Proposed Model ◽  
Gear Pumps ◽  
Water Hydraulic ◽  
Film Characteristics ◽  
Internal Gear ◽  
Shaft Journal

Water hydraulics has drawn considerable attention in recent years for its environmental friendliness. This paper presents a numerical model for analysing the lubricating gap between the gear shaft and the journal bearing in water hydraulic internal gear pumps. The model consists of two parts: the gear part that addresses the radial force on the gear shaft and the film part that addresses the film characteristics of the gear shaft/journal bearing interface. The radial force is obtained by summing the fluid pressure around the gear circumference and the meshing force of the gear pair. The film characteristics are analysed by an elastohydrodynamic model that involves the evaluation of the film geometry, the film pressure, and the elastic deformation of the gear shaft/journal bearing interface. The radial force evaluated by the gear part is balanced by the film pressure evaluated by the film part. The gear part is validated by experiments on an oil internal gear pump from the aspect of the outlet pressure ripple, and the film part is validated by comparison with the results from other research groups. The proposed model allows the evaluation of radial micro-motion as well as the eccentric positions of the gear shaft. In addition, the influence of film deformation is further discussed, suggesting that the maximum film deformation should be maintained under 1.3 times the minimum film height. The proposed model can be used as a tool for design optimization of the water-lubricated journal bearing in water hydraulic internal gear pumps.

WHICH WILL WIN IN THE GEAR PUMP TECHNOLOGY

2013 ◽  
Vol 37 (1) ◽  
pp. 129-134 ◽  
Author(s):  
Hai-Lin Zhu ◽  
Jun Pan ◽  
Min Zou ◽  
Hong-Nen Wu ◽  
Xingpei Qin
Keyword(s):  
Working Life ◽  
Radial Pressure ◽  
Radial Force ◽  
Gear Pump ◽  
Ring Gear ◽  
Flow Pulsation ◽  
Gear Pumps ◽  
New Type ◽  
Flexible Ring ◽  
Short Working

There exist three major problems in current gear pumps. They are unbalanced radial force, big excessive flow pulsation and short working life. In order to solve the problems above, a new type of gear pump with flexible ring gear is introduced. Pumping action is achieved through meshing between a flexible ring gear and a rigid external gear. Thus radial pressure forces are hydraulically balanced and the volumetric displacement is doubled for the new pump.

Design of Rotor for Internal Gear Pump Using Cycloid and Circular-Arc Curves

2012 ◽  
Vol 134 (1) ◽  
Author(s):  
T. H. Choi ◽  
M. S. Kim ◽  
G. S. Lee ◽  
S. Y. Jung ◽  
J. H. Bae ◽  
...  
Keyword(s):  
Flow Rate ◽  
Superior Performance ◽  
Correction Coefficient ◽  
Gear Pump ◽  
Circular Arc ◽  
Limit Value ◽  
Outer Rotor ◽  
Gear Pumps ◽  
Internal Fluid Flow ◽  
Internal Gear

In the case of internal gear pumps, the eccentricity of the outer rotor, which resembles a circular lobe, must be limited to a certain value in order to avoid the formation of cusps and loops; furthermore, the tip width of the inner rotor, which has a hypocycloid curve and an epicycloid curve, should not be allowed to exceed the limit value. In this study, we suggest that the tip width of the inner rotor be controlled by inserting a circular-arc curve between the hypocycloid and epicycloid curves. We also suggest that the outer rotor be designed using the closed-form equation for the inner rotor and the width correction coefficient. Thus, it is possible to design a gerotor for which there is no upper limit on the eccentricity, as in this case, undercut is prevented and there is no restriction on the tip width. We also develop an automated program for rotor design and calculation of the flow rate and flow rate irregularity. We demonstrate the superior performance of the gerotor developed in this study by analyzing the internal fluid flow using a commercial computational fluid dynamics (CFD)-code.

Manufacturing and study on influence of changes in center distance in circle arc-involute-circle arc gear pump operating at high pressure and high speed

2016 ◽  
Vol 230 (18) ◽  
pp. 3285-3297 ◽  
Author(s):  
Minghui Hao ◽  
Yang Zhou ◽  
Shuanghui Hao
Keyword(s):  
High Pressure ◽  
High Speed ◽  
End Milling ◽  
Radial Force ◽  
Numerical Control ◽  
Gear Pump ◽  
Circular Arc ◽  
Ball End Milling ◽  
Gear Pumps ◽  
Center Distance

This study examined the effect of changes in center distance on a circular-arc gear pump that operates at high pressure and high speed. In principal these types of gear pumps have no trapped-oil and flow ripples. The effect of changes in center distance caused by assembly, machining, radial force and oil film force on the performance of circular-arc gear pumps was studied. The results show that the flow rate, axial force and torque increased linearly with an increase in variables [Formula: see text]. Computer aided manufacturing for ball end milling has been developed to simulate the process of numerical control of the rotors of circular-arc gear pumps. Two methods for assessing interference are provided. The trajectories of the centers of ball end milling for rough and finish machining are simulated.

Friction torque characteristics of an internal gear pump

2011 ◽  
Vol 225 (6) ◽  
pp. 1523-1534 ◽  
Author(s):  
Y Inaguma
Keyword(s):  
Mathematical Model ◽  
Friction Torque ◽  
Operating Conditions ◽  
Gear Pump ◽  
Operating Pressure ◽  
New Model ◽  
Pump Speed ◽  
Gear Pumps ◽  
Internal Gear ◽  
Three Components

This paper describes the influence of pump operating conditions, such as operating pressures, pump speeds, and oil temperatures, on the friction torque characteristics of internal gear pumps for automobiles. Additionally, it presents a new mathematical model reflecting the influence of the oil temperature on the friction torque. In an internal gear pump, the friction torque was affected by oil temperature as well as operating pressure and pump speed. When the operating pressure was high, the influence of oil temperature on friction torque at a pump speed of less than 1000 r/min was contrary to that at a pump speed of greater than 1000 r/min. It was considered that the friction torque is fundamentally composed of three components: the component dependent on the operating pressure, dependent on the pump speed, and independent of both the operating pressure and the pump speed. However, the component dependent on the operating pressure was affected significantly by not only the pump speed but also the oil temperature. In addition, another factor besides the viscosity of the oil existed in the component dependent on the pump speed. A mathematical model for the friction torque characteristic of the internal gear pump was newly established by adding factors including the oil temperature to the Wilson’s model. The new model was able to represent with accuracy the experimental friction torque characteristic in the internal gear pump under various pump operating conditions.

Temperature rise of journal bearing of the high-speed circular arc gear pump

2019 ◽  
Vol 234 (8) ◽  
pp. 1492-1499
Author(s):  
Yang Zhou ◽  
Yuan Ci
Keyword(s):  
Temperature Rise ◽  
High Speed ◽  
Journal Bearing ◽  
Radial Force ◽  
Calculation Model ◽  
Journal Bearings ◽  
Gear Pump ◽  
Accurate Calculation ◽  
Circular Arc ◽  
Herringbone Grooves

A “circular arc–involute–circular arc” circular arc gear pump was developed based on a gear meshing principle and coordinate transformation as well as an accurate calculation model of the radial force. The dependence of the radial force on the meshing angle was investigated. The temperature rise of journal bearings in the pump was evaluated for bearings with and without herringbone grooves. Furthermore, the influence of the rotational speed and outlet pressure on this rise was assessed. The results revealed using herringbone groove on the inner wall of bearing was effective in reducing the temperature increase. Therefore, the use of grooves represents a suitable method of reducing the temperature rise in the journal bearings of a high-speed gear pump.

scholarly journals Simulation Research on Trapped Oil Pressure of Involute Internal Gear Pump

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Shanxin Guo ◽  
Xiangfeng Guan
Keyword(s):  
High Performance ◽  
Gear Pump ◽  
Outer Contour ◽  
Simulation Research ◽  
Scanning Method ◽  
Gear Pumps ◽  
Instantaneous Flow Rate ◽  
Internal Gear ◽  
Meshing Process ◽  
Internal Meshing

The main structure of an internal gear pump consisted of an internal gear pair, including an internal gear and an external gear. The internal gear pump had oil trapping phenomenon like other hydraulic gear pumps. In order to solve the oil trapping phenomenon of involute gear pump with internal meshing tooth profile, in this paper, the mathematical equation of gear outer contour is established according to the principle of generation method, and the variation law of the trapped oil area in meshing process is deduced by theoretical instantaneous flow rate obtained by scanning method. Then, the minimum trapped oil volume and unloading area are solved by the graphic method. Finally, based on fluid mechanics and dynamics, the trapped oil pressure model is obtained. The change of the trapped oil area and trapped oil pressure in a meshing cycle is simulated by MATLAB. The results show that the trapped oil area changes in a parabola, and the trapped pressure fluctuates in mountains and valleys. When the trapped area is the smallest, the trapped oil pressure reaches the peak at the corresponding corner. The research results can provide guidance for the development of high-performance internal gear pumps.

scholarly journals The design and analysis of a high-speed circular arc gear pump journal bearing

2018 ◽  
Vol 10 (12) ◽  
pp. 168781401881928 ◽  
Author(s):  
Yang Zhou ◽  
Bowen Che ◽  
Ci Yuan
Keyword(s):  
High Speed ◽  
Failure Modes ◽  
Journal Bearing ◽  
Radial Force ◽  
Journal Bearings ◽  
Gear Pump ◽  
Circular Arc

A series of problems arise when a gear pump operates at high speed, including instability of the rotor, deformation of the chamber, and wear of the journal bearing. Among all failure modes, journal bearing wear is the most serious. The wear of journal bearings of a circular arc gear pump that operates at high speed is thus presented in this article. A journal bearing that offsets the unbalanced radial force is designed by analysis of the fluid and determination of eccentricity of the gear shaft. Experiments show that the wear of the new journal bearing is effectively reduced.

Design of the conjugated straight-line internal gear pairs for fluid power gear machines

2012 ◽  
Vol 227 (8) ◽  
pp. 1776-1790 ◽  
Author(s):  
Wei Song ◽  
Hua Zhou ◽  
Yonggang Zhao
Keyword(s):  
Line Profile ◽  
Equation System ◽  
Fluid Power ◽  
Gear Pump ◽  
Gear Pair ◽  
Non Linear Equation ◽  
Straight Line ◽  
Linear Equation System ◽  
Gear Pumps ◽  
Internal Gear

The conjugated straight-line internal gear pair, including a pinion with straight-line profile and an internal gear with profile conjugated to the pinion profile, is the key components to the conjugated straight-line internal gear pumps. Truninger [ Truninger gear pump. Patent 3491698, USA, 1970] pointed that this kind of gear pairs leads to a very small trapped volume, which is 10 times smaller than that of the conventional involute internal gear pumps. Therefore, it can yield significant reduction in noise levels of the pumps. However, to the authors’ knowledge, there is no research on the design of these gear pairs until now. First, our study describes the straight-line profile of the pinion mathematically with definitions of some geometric parameters. Second, according to the theory of gearing, the mathematical models of the rack-cutter and the conjugated internal gear are derived. Then, the condition to avoid overcutting is obtained for the generation of the pinion by a rack-cutter. Finally, the condition to avoid interference in the internal gear pair is derived as a non-linear equation system and an algorithm is developed to find a numerical solution. Two examples are presented to demonstrate how to determine tooth numbers of the internal gears for avoiding interference. It is hoped that the study in this article should be helpful to the designers of the conjugated straight-line internal gear pairs. Moreover, it could provide a prepared knowledge for the researchers to investigate the performances of the fluid power gear machines, pumps, and motors, with the conjugated straight-line internal gear pumps.

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