A New Continuous Contact Low-Noise Gear Pump

1983 ◽  
Vol 105 (4) ◽  
pp. 736-741 ◽  
Author(s):  
K. Mitome ◽  
K. Seki
Keyword(s):  
Point Contact ◽  
Practical Method ◽  
Spur Gear ◽  
Helical Gear ◽  
Low Noise ◽  
Tooth Profile ◽  
Gear Pump ◽  
Excellent Performance ◽  
Continuous Contact ◽  
Gear Pumps

Developed is a new low-noise gear pump which has no trapping and whose gears are in continuous one-point contact in the plane of rotation. First this paper studies a practical method to design the tooth profile of a spur gear for a given path of contact. A new tooth profile is obtained by giving a closed path of contact like a figure 8. Basic dimensions are determined and limites of them are obtained. Both theoretical and approximate displacements are expressed in terms of the basic dimensions. Secondly, a helical gear pump is studied. The helical gear can be discussed in the same way as the spur gear by new basic dimensions. Finally some test gear pumps are made and tested. Test prove that this gear pump has excellent performance and durability.

Design and Performance of a Curvilinear Circular-Arc Tooth Gear for Gear Pump Applications

2020 ◽  
Author(s):  
Logan T. Williams
Keyword(s):  
Spur Gear ◽  
Sound Level ◽  
Tooth Profile ◽  
Gear Pump ◽  
Gear Design ◽  
External Gear Pumps ◽  
Tooth Gear ◽  
Gear Pumps ◽  
Axial Profile ◽  
And Performance

Abstract The most common gear architecture used in external gear pumps is the spur gear with an involute tooth profile. The involute spur gear has many benefits, such as a constant line of action, tolerance to parallel misalignment, and ease of fabrication. However, the involute spur gear has two major drawbacks in pump applications: the tooth profile results in trapped pockets of fluid that contribute to pressure spikes and noise generation, and the straight axial profile further increases noise due to intermittent tooth shock during meshing. Current state-of-the-art pumps utilize helical gears to enable a gradual mesh to reduce noise and pressure pulsation, which results in an axial load induced on the gears during meshing. A novel gear design has been developed that eliminates axial gear loading while preserving a gradual mesh. A hybrid tooth profile eliminates the trapped fluid pocket while maintaining the benefits of an involute profile. Initial testing demonstrates an increase in volumetric efficiency by 10% and a reduction of sound level by 7 dB compared to a spur gear of the same size.

Design of the Tooth Profile of a Full Conjugate Helical Gear Pump

2012 ◽  
Vol 566 ◽  
pp. 276-280
Author(s):  
Mao Qing Zhang ◽  
Shao Ying Zhang ◽  
Wen Jun Wei ◽  
Hai Tao Li
Keyword(s):  
Differential Geometry ◽  
Fixed Ratio ◽  
Helical Gear ◽  
Tooth Profile ◽  
The Other ◽  
Gear Pump ◽  
Continuous Space ◽  
Gear Pumps ◽  
Meshing Characteristics ◽  
Better Than

In this paper, the tooth profile of a kind of full conjugate helical gear pump was designed. The tooth profile of each of the gears is composed of three curves which are an addendum arc, an involute and a dedendum curve. The dedendum curve of one gear is the conjugate curve of the addendum arc of the other gear. The addendum arc and the dedendum curve are joined tangentially by an involute. The equations of the curves were deduced by using differential geometry. The ranges of parameters in these equations were also obtained. The meshing characteristics of the gears were analyzed. Two gears transmit continuously with a fixed ratio. Two gears engage each other point by point continuously along the entire profile and formed a continuous space meshing curve. The trapping oil phenomenon could be eliminated and the sealing property could be better than conventional involute gear pumps. The results of calculation and analysis of an application example showed the theoretical analysis and the practicability of the design were valid.

A New Gears Profile Having Zero Relative Curvature at Many Contact Points (LogiX Tooth Profile)

1990 ◽  
Vol 112 (3) ◽  
pp. 430-436 ◽  
Author(s):  
T. Komori ◽  
Y. Ariga ◽  
S. Nagata
Keyword(s):  
Point Contact ◽  
Spur Gear ◽  
Tooth Profile ◽  
Spur Gears ◽  
New Era ◽  
Contact Points ◽  
History Of ◽  
Surface Durability ◽  
New Type ◽  
Zero Values

We have successfully developed a tooth profile which enables a spur gear having zero relative curvature at contact points under the engagement through the concave/convex pattern of contact and further enables a single flank of the tooth profile to have the infinite number of points where the relative curvature and specific sliding are zero values. We have given a name of “LogiX” to this tooth profile. A W-N (Wildhaber-Novikov) tooth profi¨le has been known as that having the concave/convex pattern of contact. The tooth profile, however, is applied only to a helical gear due to its feature of a point contact. While, on the LogiX tooth profile, an improvement has been made so that a pair of spur gears having the tooth profile may contact each other through the concave/convex pattern of a line-contact which cannot be achieved by the W-N tooth profile. Therefore, the LogiX tooth profile has realized a spur gear whose surface durability is as high as that of the W-N tooth profile. Since the results of durability tests show slightly higher than an involute one, it is expected that a new type heavy duty gear of this tooth profile puts into practical use. Furthermore, the tooth profile will have the possibility of creating the new era in the history of tooth profile theory.

Application of Non-Circular Planetary Gear Mechanism in the Gear Pump

2012 ◽  
Vol 591-593 ◽  
pp. 2139-2142
Author(s):  
Hong Ding
Keyword(s):  
Pressure Fluctuations ◽  
Hydraulic Drive ◽  
Planetary Gear ◽  
Low Noise ◽  
Gear Transmission ◽  
Gear Pump ◽  
Flow Ripple ◽  
Large Pressure ◽  
Gear Pumps ◽  
Gear Mechanism

Gear pump is the most commonly used hydraulic component in hydraulic drive system.Volumetric efficiency of the traditional gear pump is low, big flow ripple causes large pressure fluctuations, makes pipes and valves vibration, noisy. The imbalance pressure on gear pump’s gears, shafts and bearings and the large radial load limits its pressure increased. Planetary gear transmission compared with ordinary gear transmission, it has many unique advantages. So the writer on the basis of the combination of proposed non-circular planetary gear pumps and gear pump works discussed the structure and working principle of the pump. The non-circular planetary gear pump with many advantages such as big flow, uniform flow, low noise and so on. It can be widely used in various hydraulic transmission systems.

Numerical Modeling of a Helical External Gear Pump With Continuous-Contact Gear Profile: A Comparison Between a Lumped-Parameter and a 3D CFD Approach of Simulation

2018 ◽  
Author(s):  
Xinran Zhao ◽  
Andrea Vacca ◽  
Sujan Dhar
Keyword(s):  
Cfd Simulation ◽  
Good Description ◽  
Helical Gear ◽  
Lumped Parameter Model ◽  
Fluid Power ◽  
Gear Pump ◽  
Continuous Contact ◽  
Positive Displacement ◽  
Lumped Parameter ◽  
Flow Features

The concept of continuous-contact helical gear pumps (CCHGP) has been proposed and successfully commercialized in the recent past. Thanks to the continuous-contact rotor profile design and to the helical gear structure, this design eliminates the kinematic flow oscillation. This has important implications on the fluid borne noise generation, which is considered as one of the major sources of noise emissions and mechanical vibrations for positive displacement machines. Although the commercial success of the CCHGP concept, there is very little published studies about the underling physics at the basis of the functioning of this type of design. This is mostly due to the complexity of the fluid domain that characterize the functioning of CCHGP units. In this paper, a transient 3D CFD study is conducted for a reference CCHGP unit for high-pressure (up to 200 bar) fluid power applications. The results of the 3D CFD simulation are compared with those given by a lumped-parameter model developed at the Maha Fluid Power Research Center of Purdue University (USA), which was previously validated against experimental results. The results show how with a proper discretization of the fluid domain the CFD simulation approach can be used for the case of helical CCHGP units. Both models provide a good description of the main features of operation of the unit. The lumped parameter model is quicker, thus suitable for fast optimization studies. However, the CFD results not only can be used to support the main assumptions done on the lumped parameter model, they also permit to gain further insight on the operation of the CCHGP unit, particularly with respect to the flow features of the meshing process.

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.

Stress Concentration factor Analysis of Helical Gear Drives with Asymmetric Teeth Profiles

2018 ◽  
Vol 24 (5) ◽  
pp. 14
Author(s):  
Mohammad Qasim Abdullah ◽  
Mohammed Abdulaal Kadum
Keyword(s):  
Stress Concentration ◽  
Stress Concentration Factor ◽  
Concentration Factor ◽  
Bending Strength ◽  
Spur Gear ◽  
Helical Gear ◽  
Tooth Profile ◽  
Bending Stress ◽  
Pressure Angle ◽  
Side Pressure

This study investigates the influence of asymmetric involute teeth profiles for helical gears on the bending stress. Theoretically, bending stress has been estimated in spur involute gears which have symmetric teeth profile by based on the Lewis, 1892 equation. Later, this equation is developed by, Abdullah, 2012. to determine the effect of an asymmetric tooth profile for the spur gear on the bending stress. And then these equations are applied with stress concentration factor once for symmetric and once other for asymmetric teeth profile. In this paper, the bending stresses for various types of helical gear with various types of asymmetric teeth profile are calculated numerically for defined the stress concentration factor. The numerical solution based on the finite element method technique which that done by using the software simulation SolidWorks 2016. The results of this study indicate that the helical gear drive with asymmetric teeth profile having 'loaded side pressure angle' of ( ) and 'unloaded side pressure angle' of ( ) is better than a helical gear with standard teeth profile having pressure angle of ( ) from the regarding of tooth bending strength. Also, notes that the great enhancement in the results of maximum tooth bending stress for modified involute of tooth profile compared with the standard teeth profile. In addition to, predict the equation of stress concentration factor which is a function of both unloaded side pressure angle and helix angle and then it used with Abdullah equation for to determine the nominal stresses in the root fillet.  

A Solution for an Electronically-Controlled Variable Delivery External Gear Pump

2017 ◽  
Author(s):  
Srinath Tankasala ◽  
Andrea Vacca
Keyword(s):  
Cost Effective ◽  
Spur Gear ◽  
Gear Pump ◽  
Electronic Control ◽  
Pump Design ◽  
Flow Variation ◽  
Electronic Control System ◽  
Gear Pumps ◽  
Pressure Compensation ◽  
External Gear Pump

This paper describes an innovative design concept to enable electronic control of the flow delivered by external spur gear pumps. The basic principle used to obtain flow variation relies on a variable timing concept previously demonstrated by the author’s research team. This principle permits to vary the flow within a certain range, without introducing additional sources of power loss. Previous work proved the applicability of the proposed concept in a pressure compensated design of an external gear pump for high pressure applications. This concept took advantage of the pressure differential acting on the “slider”, which is an internal element performing the flow regulation. In this paper, a solution that permits to achieve balance of the pressure forces acting on the slider is proposed. This solution reduces the actuation forces, thus enabling direct flow control actuation through an electronic control system. The proposed solution is cost effective, it consists of a limited number of parts, and it is suitable for pumps without pressure compensation, i.e. for low or intermediate pressures. The paper details the aspects of the pump design, which was performed by using a multi-objective algorithm that maximizes the flow operating range and at the same time the pump. The optimum design could achieve a flow variation of about 32% in simulation and this was also demonstrated in actual experiments on a prototype realized at the author’s Research Center. The proposed design can impact several of the current applications of external gear pumps, introducing the additional “flow on demand” capability.

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