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.

Friction of outer rotor affecting friction torque characteristics in an internal gear pump

2014 ◽  
Vol 229 (16) ◽  
pp. 3013-3026 ◽  
Author(s):  
Yoshiharu Inaguma
Keyword(s):  
Pressure Distribution ◽  
Friction Force ◽  
Significant Loss ◽  
Friction Torque ◽  
The Body ◽  
Gear Pump ◽  
Suction Pressure ◽  
Outer Rotor ◽  
Internal Gear ◽  
Outer Circumference

This article presents the friction torque in an internal gear pump and the friction force between an outer circumference of an outer rotor and a body, which causes a significant loss, has been investigated. When in use at a high pressure, the pump has a large friction torque due to the friction force acting on the outer rotor circumference. This friction force is caused by imbalanced force acting on the outer rotor. As well as by a positioning suction and a delivery port, the force can be reduced by setting a suction pressure recess in a section of the outer rotor circumference. In this study, through the measurement of the friction torque in an actual pump and the pressure distribution on the outer circumference of the outer rotor, it is investigated how the suction pressure recess can change the force acting on the outer rotor. The actual internal gear pump without the suction pressure recess has a large friction torque, and it corresponds to a large force on the outer rotor, which is calculated from the pressure distributions on the inside and outside of the outer rotor. In addition, on the basis of the measured friction torque of the test pump and the force acting on the outer rotor, calculated using the results of the pressure distribution, the coefficient of friction between the outer rotor circumference and the body can be estimated.

Experimental Investigation of Flowrate Irregularity in Rotary Gear Pumps

1992 ◽  
Author(s):  
G. Mimmi
Keyword(s):  
Experimental Investigation ◽  
Flow Rate ◽  
Experimental Tests ◽  
Periodic Variation ◽  
Experimental Results ◽  
Gear Pump ◽  
Gear Pumps ◽  
Hot Film ◽  
Instantaneous Flow Rate ◽  
External Gear Pump

Abstract In a previous paper the author proposed a method to reduce the periodic variation in flow rate for an external gear pump. To verify the experimental results, a series of experimental tests on a expressly realized gear pump, was carried out. The pump was equipped with relieving grooves milled into the side plates. The tests were done on a closed piping specifically realized and equipped for measuring the instantaneous flow rate of the fluid through a wedge-shaped hot film probe.

Design of Asymmetric Double Circular Arc Gear for Large-Scale High-Pressure Gear Pumps

2011 ◽  
Vol 181-182 ◽  
pp. 361-365 ◽  
Author(s):  
Yuan Wei Liu ◽  
Jia Fan
Keyword(s):  
High Pressure ◽  
Large Scale ◽  
Large Displacement ◽  
Gear Pump ◽  
Constant Flow ◽  
Circular Arc ◽  
Bright Future ◽  
Gear Pumps

In this paper, an asymmetric double circular arc gear which is suitable for large-scale high-pressure gear pumps is introduced. While demonstrated its superiority, the displacement formula of the double circular arc gear pump is derived and the gear parameters are identified. The asymmetric double circular arc gear can meet the needs of large displacement and high pressure. There are advantages such as constant flow, no pulse, and no topping, which make this kind of gear has a bright future.

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.

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.

Experimental and numerical analysis of a self-circulating oil bearing system for gear pumps

2018 ◽  
Vol 70 (1) ◽  
pp. 115-125 ◽  
Author(s):  
Mo Jintao ◽  
Gu Chaohua ◽  
Pan Xiaohong ◽  
Zheng Shuiying ◽  
Ying Guangyao
Keyword(s):  
Flow Rate ◽  
Pressure Difference ◽  
The Self ◽  
Gear Pump ◽  
Moderate Pressure ◽  
Test Rig ◽  
Content Type ◽  
Oil Flow ◽  
Gear Pumps ◽  
Bearing System

Purpose For moderate pressure and high pressure gear pumps, the temperature failure problem of bearings is now of considerable concern because of their heavy loads. However, the compact structure and the efficiency consideration make it extremely difficult to improve the bearing cooling. A self-circulating oil bearing system is developed for gear pumps with self-lubricating bearings to solve this problem. The oil is aspirated in from the low pressure chamber of the gear pump and discharged to the same chamber by using the pressure difference in the journal bearing, thus achieving the self-circulation. Design/methodology/approach An experiment test rig has been built for the feasibility study. The oil flow rate under different speeds has been recorded. Furthermore, the temperatures of the bearings with or without the oil circulation have been compared. Additionally, the oil flow in the test rig has been simulated using computational fluid dynamics codes. Findings The experimental and numerical results agree well. The experimental results indicate that the oil flow rate increases approximately linearly with the speed and the bearing temperature can be lowered successfully. The calculation results indicate that the bearing load capacity is nearly the same. Both the experimental and numerical studies establish that the self-circulating oil bearing system works successfully. Originality value As far as the authors know, it is the first time to find that the self-circulation can be built using the pressure difference in the bearing oil film, and this principle can be applied in the cooling and lubrication of the gear pumps to solve the temperature failure problem.

scholarly journals Experimental and Numerical Study on the Flow Ripple of Circular-arc Gear Pumps Considering the Center Distance Deviation

2021 ◽  
Author(s):  
Xiaoling Wei ◽  
Yongbao Feng ◽  
Zhenxin He ◽  
Ke Liu
Keyword(s):  
Pressure Pulsation ◽  
Numerical Study ◽  
Fluid Dynamic ◽  
Gear Tooth ◽  
Tooth Profile ◽  
Gear Pump ◽  
Circular Arc ◽  
Gear Pumps ◽  
Distance Deviation ◽  
Center Distance

Abstract Novel circular-arc gear pumps effectively solve the problems of oil trapping and flow pulsation experienced with traditional gear pumps. However, the center distance deviation associated with assembly and installation during gear pump processing has an important influence on the outlet pressure pulsation characteristics of circular-arc gear pumps. First, the circular-arc tooth profile equation, conjugate curve equation and meshing line equation were derived to design the circular-arc gear meshing and center distance deviation functions. Second, the circular-arc gear tooth profile was accurately obtained. Then, a pressure pulsation characteristic simulation model for the novel circular-arc gear pumps considering the center distance deviation was established. The results show that with the increase of center distance deviation, the outlet flow rate of the arc gear pump increases first and then decreases greatly. Moreover, the center distance deviation has little effect on the independent tooth cavity pressure. Finally, the proposed fluid dynamic model is used to simulate a commercial circular-arc gear pump, which was tested within this research for modeling validation purposes. The comparisons highlight the validity of the proposed simulation approach.

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.

Design and CFD analysis of gerotor with multiple profiles (ellipse–involute–ellipse type and 3-ellipses type) using rotation and translation algorithm

2015 ◽  
Vol 230 (5) ◽  
pp. 804-823 ◽  
Author(s):  
Jun Ho Bae ◽  
Hyo Seo Kwak ◽  
Sereisith San ◽  
Chul Kim
Keyword(s):  
Flow Rate ◽  
Fuel Efficiency ◽  
Flow Characteristics ◽  
Internal Flow ◽  
Optimal Designs ◽  
Sintering Process ◽  
Ansys Cfx ◽  
Gear Pumps ◽  
Internal Gear ◽  
Specific Sliding

Gerotor is a key component used in internal gear pumps of vehicles, and as the technology of sintering process is highly advanced, the gerotor has advantages for manufacturing complex profiles and obtaining durability and minimization. But internal gear pumps have been continuously required to improve flow rate and noise for fuel efficiency. The existing gerotors with multiple profiles have been designed by only translation algorithm, which is limited to improve the performances. In this study, a new automated design and multiple calculation programs using rotation and translation algorithm were developed for improving the performances of multiple profiles, and two types of combined multiple profiles (ellipse 1-involute-ellipse 2 type and 3-ellipses type) were generated. The performances (flow rate, irregularity, specific sliding and pressure angle) of the profiles were calculated by using theoretical analysis, and optimal designs of the two types were carried out on the basis of analysis results. Also, internal flow characteristics in the optimized gerotor generated were analyzed by using commercial CFD (computational fluid dynamics) code, ANSYS-CFX.

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