Rotor Behavior and Friction Torque Characteristics of a Gerotor Pump Used for Automatic Transmissions

2021 ◽  
Author(s):  
Hideki Yanada ◽  
Takumi Uchino ◽  
Takahiro Takeno ◽  
Ryo Kojima ◽  
Hiroshi Yokoyama
Keyword(s):  
Dimensionless Parameter ◽  
Viscous Friction ◽  
Friction Torque ◽  
Operating Conditions ◽  
Oil Viscosity ◽  
Automatic Transmissions ◽  
Outer Rotor ◽  
Gerotor Pump ◽  
Gerotor Pumps ◽  
Driving Torque

Abstract Rotor behavior may affect the torque characteristics of gerotor pumps, but the measurement of the behavior has received little attention. Thus, in this study, we measure the rotor behavior of a gerotor pump used for automatic transmissions under various operating conditions. The experiments revealed that the inner rotor rotated near the middle of the cover wall and casing sidewall, slightly tilted with respect to them. The outer rotor rotated in the vicinity of the casing sidewall and came closer to the sidewall with decreases in the dimensionless parameter ?N??P (where ? [Pa?s] is the oil viscosity, N [s^(-1) ] is the rotational speed, and ?P [Pa] is the pressure difference). In addition, the eccentricity of the outer rotor was observed to increase with decreases in ?N??P. The inclination of the inner rotor and the approximation of the outer rotor to the casing sidewall may increase the driving torque of the pump. Taking the measured results on rotor behavior into account, a clear physical meaning is given to an existing mathematical model of viscous friction torque.

Improving Gerotor Pump Performance Trough Design, Modeling and Simulation

2021 ◽  
Author(s):  
Lozica Ivanović ◽  
Miloš Matejić
Keyword(s):  
Low Noise ◽  
Operating Conditions ◽  
Design Parameters ◽  
Pump Efficiency ◽  
Hydraulic Systems ◽  
Wear Process ◽  
Gerotor Pump ◽  
Gerotor Pumps ◽  
Negative Effect ◽  
Compact Design

Gerotor pumps are well known by a compact design, simple structure and low noise level, which makes them suitable for use in the automotive industry, and especially in hydraulic systems for engine lubrication. One of the main disadvantages of gerotor pumps is the inability to adjust to wear, which significantly reduces the pump efficiency. In order to mitigate the negative effect of the inevitable wear process, this paper presents a methodology for determining the optimal combination of trochoid gears design parameters for a defined aspect. An appropriate mathematical model has been developed to analyze the effect of changes in gear design parameters in relation to maximum contact stresses, pressure changes in gerotor pump chambers and wear rate proportional factor (WRPF). Verification of the developed models was performed by realizing physical pairs of gears and laboratory experiments with simulation of pump operating conditions. The results and conclusions presented in this paper, with an emphasis on the actual work processes, bring very important perspectives for the gerotor pumps design with improved performance.

Experimental Investigation of the Cylinder Block Movement in an Axial Piston Machine

2015 ◽  
Author(s):  
Stephan Wegner ◽  
Stefan Gels ◽  
Dal Sik Jang ◽  
Hubertus Murrenhoff
Keyword(s):  
Viscous Friction ◽  
Friction Torque ◽  
Operating Conditions ◽  
Valve Plate ◽  
Measuring System ◽  
Cylinder Block ◽  
Experimental Investigations ◽  
German Research Foundation ◽  
Block Movement ◽  
Axial Piston

The greatest share of hydromechanic and volumetric losses in axial piston machines are produced within the tribological interfaces piston / cylinder, cylinder block / valve plate and slipper / swash plate. Hydrostatic and hydrodynamic effects are used to minimise the sum of solid friction, viscous friction and throttle losses. Other tribological interfaces have minor influence on efficiency losses in most operating points in machines of this type. This paper focuses on experimental investigations with the objective to acquire further knowledge on the cylinder block / valve plate contact. The investigations are part of a project funded by the German Research Foundation in which experimental and simulative investigations are combined to identify the effects influencing this tribological interface. The experiments focus on the multi-directional movement of the cylinder block and the friction torque within the contact. Therefore a test rig was built, capable of measuring the cylinder block movement in all degrees of freedom and the friction torque between both parts. A sensor system is built around a standard rotary group of an axial piston pump with a spherical cylinder block / valve plate contact. The pump functionality is maintained and measurements under standard operating conditions up to 30 MPa are possible. Procedures of the design process and descriptions of the measuring system are presented, followed by results of the cylinder block movement measurement, comparing the behavior under different pressure levels and speeds.

Dynamic Analysis of Piston Secondary Motion for Small Reciprocating Compressors

2000 ◽  
Vol 122 (4) ◽  
pp. 752-760 ◽  
Author(s):  
A. T. Prata ◽  
J. R. S. Fernandes ◽  
F. Fagotti
Keyword(s):  
Viscous Friction ◽  
Problem Formulation ◽  
Operating Conditions ◽  
Oscillatory Motion ◽  
Design Parameters ◽  
Radial Clearance ◽  
Oil Viscosity ◽  
Time Step ◽  
Present Contribution ◽  
Oil Leakage

Piston dynamics plays a fundamental role in two critical processes related to fluid flow in reciprocating compressors. The first is the gas leakage through the radial clearance, which may cause considerable loss in the pumping efficiency of the compressor. The second process is the viscous friction associated with the lubricant film in the radial clearance. In the present contribution a numerical simulation is performed for a ringless piston inside the cylinder of a reciprocating compressor, including both the axial and the radial piston motion. The compressor considered here is a small hermetic compressor employed in domestic refrigerators, with the radial clearance between piston and cylinder filled with lubricant oil. In operation, the piston moves up and down along the axis of the cylinder, but the radial oscillatory motion in the cylinder bore, despite being usually small, plays a very important role on the compressor performance and reliability. The compromise between oil leakage through the piston-cylinder clearance and the friction losses requires a detailed analysis of the oscillatory motion for a good design. All corresponding forces and moments are included in the problem formulation of the piston dynamics in order to determine the piston trajectory, velocity and acceleration at each time step. The hydrodynamic force is obtained from the integration of the pressure distribution on the piston skirt, which, in turn, is determined from a finite volume solution of the time dependent equation that governs the oil flow. A Newton-Raphson procedure was employed in solving the equations of the piston dynamics. The results explored the effects of some design parameters and operating conditions on the stability of the piston, the oil leakage, and friction losses. Emphasis was placed on investigating the influence of the pin location, radial clearance and oil viscosity on the piston dynamics. [S0742-4787(11)00301-8]

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.

Modelling and Analysis of a Grout Delivery Mechanism in the Remote Spray Lining of Shafts

1996 ◽  
Author(s):  
Liu Hongzhao ◽  
E. Appleton
Keyword(s):  
Relative Velocity ◽  
Viscous Friction ◽  
Emission Angle ◽  
Inertia Force ◽  
Viscous Damping ◽  
Friction Forces ◽  
Viscous Friction Force ◽  
Full Discussion ◽  
Delivery Mechanism ◽  
Driving Torque

Abstract A thorough analysis on the characteristics of a grout delivery mechanism in the lining of shafts has been accomplished. The dynamic equation of this spraying mechanism has been established and can describe the system’s performance properties under different conditions of viscous friction forces. The analysis introduces a combined viscous damping coefficient c* and a ratio λ between viscous friction force and inertia force. It is proved theoretically that the relative velocity of the grout is less than the implicate velocity and the emission angle α described in the paper is always larger than 45 °. Numerical simulations are performed by feeding various different parameters into the model. A full discussion of the effects of different variables is presented. Additionally, a formula for calculating the driving torque and power is developed. These studies provide an understanding of the properties of this mechanism and should prove useful in guiding its design and operation.

Turbocharger Radial Turbine Response to Pulse Amplitude

2021 ◽  
Author(s):  
Roberto Mosca ◽  
Shyang Maw Lim ◽  
Mihai Mihaescu
Keyword(s):  
Heat Transfer ◽  
Continuous Flow ◽  
Viscous Friction ◽  
Pulse Amplitude ◽  
Operating Conditions ◽  
System Response ◽  
Maximum Speed ◽  
Detached Eddy Simulation ◽  
Beneficial Effects ◽  
Eddy Simulation

Abstract Under on-engine operating conditions, a turbocharger turbine is subject to a pulsating flow and, consequently, experiences deviations from the performance measured under continuous flow. Furthermore, due to the high exhaust gas temperatures, heat transfer further deteriorates the turbine performance. The complex interaction of the aerothermodynamic mechanisms occurring inside the hot-side, and consequently the turbine behavior, is largely affected by the shape of the pulse, which can be parameterized through three parameters: pulse amplitude, frequency, and temporal gradient. This paper investigates the hot-side system response to the pulse amplitude via a Detached Eddy Simulation (DES) approach of a radial turbocharger turbine system including exhaust manifold. Firstly, the computational model is validated against experimental data obtained under gas stand continuous flow conditions. Then, two different mass flow pulses, characterized by a pulse amplitude difference of ≈ 5%, are compared. An exergy-based post-processing approach shows the beneficial effects of increasing pulse amplitude. An improvement of the turbine power by 1.3%, despite the increment of the heat transfer and total internal irreversibilities by 5.8% and 3.4%, respectively, is reported. As a result of the higher maximum speed, internal losses by viscous friction are responsible for the growth of the total internal irreversibilities as pulse amplitude increases.

The Influence of Lubricant Supply Conditions and Bearing Configuration on the Performance of (Semi) Floating Ring Bearing Systems for Turbochargers

2017 ◽  
Author(s):  
Luis San Andrés ◽  
Feng Yu ◽  
Kostandin Gjika
Keyword(s):  
Heat Flow ◽  
Thermal Energy ◽  
Operating Conditions ◽  
Temperature Fields ◽  
Engine Oil ◽  
Large Temperature ◽  
Oil Viscosity ◽  
Supply Pressure ◽  
The Impact ◽  
Bearing System

Engine oil lubricated (semi) floating ring bearing (S)FRB systems in passenger vehicle turbochargers (TC) operate at temperatures well above ambient and must withstand large temperature gradients that can lead to severe thermo-mechanical induced stresses. Physical modeling of the thermal energy flow paths and an effective thermal management strategy are paramount to determine safe operating conditions ensuring the TC component mechanical integrity and the robustness of its bearing system. On occasion, the selection of one particular bearing parameter to improve a certain performance characteristic could be detrimental to other performance characteristics of a TC system. The paper details a thermohydrodynamic model to predict the hydrodynamic pressure and temperature fields and the distribution of thermal energy flows in the bearing system. The impact of the lubricant supply conditions (pressure and temperature), bearing film clearances, oil supply grooves on the ring ID surface are quantified. Lubricating a (S)FRB with either a low oil temperature or a high supply pressure increases (shear induced) heat flow. A lube high supply pressure or a large clearance allow for more flow through the inner film working towards drawing more heat flow from the hot journal, yet raises the shear drag power as the oil viscosity remains high. Nonetheless, the peak temperature of the inner film is not influenced much by the changes on the way the oil is supplied into the film as the thermal energy displaced from the hot shaft into the film is overwhelming. Adding axial grooves on the inner side of the (S)FRB improves its dynamic stability, albeit increasing the drawn oil flow as well as the drag power and heat flow from the shaft. The predictive model allows to identify a compromise between different parameters of groove designs thus enabling a bearing system with a low power consumption.

Investigation of Squeeze Film Damper Forces Produced by Circular Centered Orbits

1978 ◽  
Vol 100 (1) ◽  
pp. 15-21 ◽  
Author(s):  
E. Feder ◽  
P. N. Bansal ◽  
A. Blanco
Keyword(s):  
Aircraft Engine ◽  
Analytical Investigation ◽  
Operating Conditions ◽  
Squeeze Film ◽  
Oil Viscosity ◽  
Pressure Transducers ◽  
Pressure Distributions ◽  
Pressure Profiles ◽  
Force Components ◽  
Type Pressure

This paper presents the results of an experimental and analytical investigation of the dynamic forces generated by a squeeze film bearing damper constrained to move in circular centered orbits. These orbits were mechanically produced in a specially designed, end sealed, test rig. Aircraft engine damper geometry and operating conditions were simulated. The effect of journal speed, oil viscosity, inlet pressure, and eccentricity ratio on the damper performance was studied. The pressure distributions about the journal were measured for each test condition by high-response diaphragm-type pressure transducers. These pressure profiles were numerically integrated to determine the force components of the squeeze film. Experimental results were compared to an analysis which is summarized in this paper and included the effects of inlet and cavitation pressures. The “long bearing theory” was found to be reasonably accurate in predicting the shape and magnitude of the pressure distribution. Considerable emphasis was directed to the study of the circumferential pressure distributions between 180 deg and 360 deg since aircraft engine dampers generally operate in this region. For the cavitated film (i.e., pressure distributions less than 360 deg), accurate prediction of the damper forces was found to be critically dependent on the effect of inlet and cavitation pressures.

Posture measurement of gear in internal gear pump and consideration on viscous friction torque model

2020 ◽  
Vol 2020 (0) ◽  
pp. S11113
Author(s):  
Takahiro TAKENO ◽  
Ryo KOJIMA ◽  
Takumi UCHINO ◽  
Hiroshi YOKOYAMA ◽  
Hideki YANADA
Keyword(s):  
Viscous Friction ◽  
Friction Torque ◽  
Gear Pump ◽  
Internal Gear ◽  
Posture Measurement

Gas Purging System to Extend Thrust Bearing Life in ESPs

2021 ◽  
Author(s):  
Jose Caridad ◽  
Arthur Watson ◽  
Song Shang ◽  
Eric Nguyen ◽  
Gocha Chochua
Keyword(s):  
Thrust Bearing ◽  
Operating Conditions ◽  
Design Parameters ◽  
Motor Oil ◽  
Oil Viscosity ◽  
Test Fixture ◽  
Thrust Bearings ◽  
Working Volume ◽  
Gas Purging ◽  
Critical Components

Abstract Electric submersible pump (ESP) systems use thrust bearings in the seal section to handle the thrust generated by the pump stages. Thrust bearings are subjected to harsh operating conditions, including high loads, poor oil circulation, and motor oil viscosity degradation. A less-recognized issue is gas becoming centrifugally trapped under the thrust runner. The gas may be present because of incomplete purging of air during filling, permeation of well gas into the motor oil, or gradual gasification of motor oil at high temperatures. Because thrust bearings are such critical components, it is of interest to increase their reliability, which in turn will increase ESP life. A novel gas purging system (GPS) was designed to alleviate stressors on thrust bearings, including gas accumulation, viscosity deterioration and gasification at high temperature, and low working oil volume. GPS circulates oil along with any gas that accumulates under the thrust runner up to a quiet separation chamber. Degassed oil circulates back to the thrust bearing, while accumulated gas eventually purges to the wellbore through relief valves on subsequent on/off cycles. GPS also improves viscosity and reduces gasification by cooling the oil, and it provides a greater working volume of thrust bearing oil to reduce the effects of oil deterioration. This paper details the GPS design principles as well as the optimization of the different design parameters that affect its performance conducted via computational fluid dynamics (CFD). Observations captured on a test fixture built using the final configuration are also presented, validating the intended functionality.

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