Showing papers on "Gear pump published in 2020"

Research on Flow Characteristics of Straight Line Conjugate Internal Meshing Gear Pump

Abstract: The improvement of the overall performance of hydraulic pumps is the basis of intelligent hydraulics. Taking the straight line conjugate internal meshing gear pump as the research object, the theoretical flow rate and the geometric flow pulsation rate equations are established in this study through the volume change method. The change laws of the gear pair’s geometric parameters on the theoretical flow rate and the geometric flow pulsation rate are studied. The simulation model of the internal flow channel is established, and the influence factors and the influence degree of the flow pulsation and average flow rate are analyzed. The high-pressure positive displacement pump test system is also designed and built. The performance evaluations are conducted, and the experimental results are analyzed. The results show that the periodic change of the meshing point position is the root cause of the geometric flow pulsation. The theoretical flow rate and the geometric flow pulsation rate are 103.71 L/min and 1.76%, respectively. To increase the theoretical flow rate whilst decreasing the geometric flow pulsation rate, the tip circle radius of the external gear should be increased as much as possible within the allowable range of the design calculation. Amongst the three influencing factors that produce flow pulsation, the oil compressibility has no effect on the flow pulsation. The uneven internal leakage is the main factor, and the geometric flow pulsation only accounts for a small proportion. The internal leakage reduces the simulated flow rate by 3.59 L/min. The difference between the experimental and simulated flow rates is less than 2%. Within the allowable speed range, the rotation speed of the external gear should be increased as much as possible to increase the average flow rate and the volumetric efficiency.

Effect of Energy Recovery on Efficiency in Electro-Hydrostatic Closed System for Differential Actuator

Abstract: This paper investigates energy efficiency and dynamic behavior through simulation and experiments of a compact electro-hydrostatic actuator system (EHA) consisting of an electric motor, external gear pump/motors, hydraulic accumulator, and differential cylinder. Tests were performed in a stand-alone crane in order to validate the mathematical model. The influence and importance of a good balance between pump/motors displacement and cylinder areas ratios is discussed. The overall efficiency for the performed motion is also compared considering the capability or not of energy recovery. The results obtained demonstrate the significant gain of efficiency when working in the optimal condition and it is compared to the conventional hydraulic system using proportional valves. The proposed system presents the advantages and disadvantages when utilizing components off-the-shelf taking into account the applicability in mobile and industrial stationary machines.

Remaining Useful Life Prediction Based on the Bayesian Regularized Radial Basis Function Neural Network for an External Gear Pump

Abstract: A remaining useful life (RUL) prediction method for an external gear pump is proposed by Bayesian regularized radial basis function neural network (Trainbr-RBFNN). The variational mode decomposition (VMD) algorithm has been used to denoise the vibration data of accelerated degradation test, followed by which, using the Hilbert modulation the reconstructed signal has been demodulated. After which, compared with the ensemble empirical mode decomposition (EEMD) algorithm and the modified ensemble empirical mode decomposition (MEEMD) algorithm. Subsequently, factor analysis (FA) has been selected to realize the fusion of various characteristic parameters, after which, the external gear pump’s degradation evaluation index established and analyzed. Finally, the degradation evaluation index has been used to train the Trainbr-RBFNN model, and achieve gear pump degradation evaluation model for RUL prediction. Experiment results evidence that the RUL of the external gear pump can be accurately evaluated with the method used.

Design and Operational Control Strategy for Optimum Off-Design Performance of an ORC Plant for Low-Grade Waste Heat Recovery

Abstract: The applicability of organic Rankine cycle (ORC) technology to waste heat recovery (WHR) is currently experiencing growing interest and accelerated technological development. The utilization of low-to-medium grade thermal energy sources, especially in the presence of heat source intermittency in applications where the thermal source is characterized by highly variable thermodynamic conditions, requires a control strategy for off-design operation to achieve optimal ORC power-unit performance. This paper presents a validated comprehensive model for off-design analysis of an ORC power-unit, with R236fa as the working fluid, a gear pump, and a 1.5 kW sliding vane rotary expander (SVRE) for WHR from the exhaust gases of a light-duty internal combustion engine. Model validation is performed using data from an extensive experimental campaign on both the rotary equipment (pump, expander) and the remainder components of the plant, namely the heat recovery vapor generator (HRVH), condenser, reservoirs, and piping. Based on the validated computational platform, the benefits on the ORC plant net power output and efficiency of either a variable permeability expander or of sliding vane rotary pump optimization are assessed. The novelty introduced by this optimization strategy is that the evaluations are conducted by a numerical model, which reproduces the real features of the ORC plant. This approach ensures an analysis of the whole system both from a plant and cycle point of view, catching some real aspects that are otherwise undetectable. These optimization strategies are considered as a baseline ORC plant that suffers low expander efficiency (30%) and a large parasitic pumping power, with a backwork ratio (BWR) of up to 60%. It is found that the benefits on the expander power arising from a lower permeability combined with a lower energy demand by the pump (20% of BWR) for circulation of the working fluid allows a better recovery performance for the ORC plant with respect to the baseline case. Adopting the optimization strategies, the average efficiency and maximum generated power increase from 1.5% to 3.5% and from 400 to 1100 W, respectively. These performances are in accordance with the plant efficiencies found in the experimental works in the literature, which vary between 1.6% and 6.5% for similar applications. Nonetheless, there is still room for improvement regarding a proper design of rotary machines, which can be redesigned considering the indications resulting from the developed optimization analysis.

A new hybrid model of sparsity empirical wavelet transform and adaptive dynamic least squares support vector machine for fault diagnosis of gear pump

Abstract: Gear pump is the key component in hydraulic drive system, and it is very significant to fault diagnosis for gear pump. The combination of sparsity empirical wavelet transform and adaptive dynamic l...

Development of CFD-based procedure for 3d gear pump analysis

Abstract: Tumbling Multi-Chamber (TMC) gear pump is a generally unknown type of hydraulic device, which features a unique three-dimensional shape of the gears. The main benefits of such design over the conve...

Research on Identification Method of Wear Degradation of External Gear Pump Based on Flow Field Analysis.

Abstract: As a kind of hydraulic power component, the external gear pump determines the performance of the entire hydraulic system. The degradation state of gear pumps can be monitored by sensors. Based on the accelerated life test (ALT), this paper proposes a method to identify the wear degradation state of external gear pumps based on flow field analysis. Firstly, the external gear pump is theoretically analyzed. Secondly, dynamic grid technology is used to simulate the internal flow field of the gear pump in detail. Finally, the theoretical and simulation results are verified by the ALT. The results show that this method can effectively identify the wear degradation status of four sample pumps. The results of the work not only provide a solution to the research on the wear degradation of external gear pumps, but also provide strong technical support for the predictive maintenance of hydraulic pumps.

Hydraulic Pressure-Flow Rate Control of a Pallet Handling Robot for an Autonomous Freight Delivery Vehicle

Abstract: The current paper presents an upgrade of a pre-installed hydraulic system for the operation of a pallet handling robot for a freight delivery vehicle known as FURBOT (freight urban robotic vehicle). The automated forklift installed on FURBOT for loading/unloading of cargo is powered with the help of hydraulics. The previous hydraulic system worked via a classical approach with a fixed displacement pump and a bypass valve, making it work on full power when in use. An alternative design was proposed, simulated and installed on FURBOT; it uses a fixed displacement pump and changes the rotation speed in real time using a pressure sensor. Novelty was attained with the use of gear pumps for said scenario. A control algorithm is implemented in the processing unit for controlling the speed of the motor driving the pump. The main advantage of this approach is better use of energy for the vehicle’s battery. The aim of this research is to control both the speed and maximum force exerted by the actuators with the help of a single sensor and an inexpensive pump.

Gear Pump Root Cause Failure Analysis Using Vibrations Analysis and Signal Processing

Abstract: In this paper, gear pump failure because of bush bearing looseness is investigated. Vibrations analysis is one of the main manners of the diagnosis of mechanical failure. After bearing looseness, gears clearance is changed because of change between gears’ clearances. Time signal, spectrum velocity, spectrum accelerations, envelope velocity, and envelope accelerations are methods of vibrations analysis and signal processing to diagnose a failure in rotary machines. In this study, bush bearing failure and adhesive wear in gear using signal processing including machine spectrum, envelope spectrum acceleration, and acceleration spectrum are detected. Gear failure because of bush looseness has many symptoms that these symptoms are pronounced in this research. The best time for failure detection is the beginning of failure so the beginning of bush and worn gear’s teeth failure was found in this paper.

Tooth Profile Optimization for Mixing Proportional Pump of Solvent-Free Laminating Mixer

Abstract: The accuracy and uniformity of mixing ratio directly affect the quality of solvent-free laminating products. In this paper, the gear pump as a proportional metering in the solvent-free laminating mixer is modeled and analyzed. The flow pulsation generated by the gear pump during the working process is studied. By establishing the formula of instantaneous flow at the outlet of the arc gear pump, the factors which affect the flow pulsation of arc gear pump are studied. An optimization model of the tooth profile parameters of the arc gear pump is constructed whose goal is to minimize the flow pulsation coefficient. Through the simulation, the results show that the optimized tooth profile parameter of arc gear pump can guarantee a more stability flow quantity. Finally, an arc gear pump flow experiment platform is found, and the experiment results verify the advantages of the optimized result.

Thermal Modelling of External Gear Machines and Experimental Validation

Abstract: The flow of energy within external gear machines (EGMs) leads to the variation of fluid temperature in the EGMs, which affects their performance. However, the common approaches for the simulation of EGMs assume isothermal conditions. This isothermal assumption negatively impacts their modelling accuracy in terms of the internal flows which are dependent on the fluid temperature (via fluid properties). This paper presents a lumped parameter based thermal model of EGMs where the fluid temperature in the EGM is evaluated considering the effects of compression/expansion, internal flows, and power losses. Further, numerical techniques are developed to model each of these three aspects. The thermal model is validated via the outlet temperature and volumetric efficiency measurements obtained from experiments conducted on six units of an EGM taken as a reference with different internal clearances. The results from the model show that the fluid temperature increases as it is carried from the inlet side to the outlet side during the pumping operation. However, the fluid at the ends of the shafts has the highest temperature. By comparing the isothermal simulation results with the proposed thermal model, the results also point out how the isothermal assumption becomes inaccurate, particularly in conditions of low volumetric efficiency.

Optimization of an External Gear Pump using Response Surface Method

Abstract: Design of a new gear pump requires many considerations to get good pump efficiency. In order to achieve optimal results, all parameters must be optimized from the design stage. In this study, ANSYS CFX was used to make parametric analysis in order to optimize a new design of gear pump. Two parameters which are inlet diameter and rotation speed are considered. The response surface method gives an optimum design point for inlet diameter of 15mm and rotation speed of 3500 rev/min. Twin vortices are created in the inlet and the outlet of pump, which strangle the flow. In order to reduce their negative effects on the flow, fillets are created at the inlet and the outlet of the pump.

Experimental Investigation of Polymer Matrix Composites Gears with Different Fiber Proportions

Abstract: Nowadays many of the conventional materials are effectively replaced by composite materials, because of their light weight to stiffness ratio. Gears are the very essential components in mechanical power transmission, and drive in the most industrial rotating machinery. Polymer gears are used in motion and power transmission under different loads and speeds. Gears are generally made from metallic materials but recently advanced polymeric materials were developed because of low cost, light weight, high strength and improved performance of the system. Nylon, polymers, acetal and derlin are the structural polymeric materials used in printing and robotics, mechanical machines such as washing machines, sugarcane crushing machine and gear pump that are used for power and speed transmission. The paper investigates the polymer matrix composites gear with different fiber proportions. The main objective is to make glass fiber reinforced polymer gears using epoxy resin with various proportions of E-glass CSM (5%, 10%, 15%, 20%). The work investigates the wear testing of polymer gears of different proportions with metal gear using gear testing rig. The paper focused on morphology of fractured surfaces of polymer gears using scanning electron microscope. Finally, the gear is modeled in Catia software and imported to Ansys for static structural application.

Calculation of Unloading Area of Internal Gear Pump and Optimization

Abstract: In order to obtain the calculation method of the unloading area of the internal gear pump during oil trapping, a pair of internal gears including an external gear and an internal gear was used as the research object to simulate the oil trapping process. The geometric relationship during the meshing process was established, and the unloading area expression was obtained by using the geometric pattern expansion method with the variable f as the independent variable. Guided by a mathematical model, two improved optimization schemes were proposed for the internal gear tooth profile, and the unloading area expressions sud, suda, and sudb were obtained. Taking the meshing gear pair with module 3 and number of teeth 13/19 as examples, the simulation results were very consistent with the existing literature. The reliability of the model and the feasibility of the optimization scheme are obtained based on the theoretical analysis and calculation results. This calculation method of unloading area can be applied to the same type of gear pump design in the future, providing a reference for the design of high pressure and low noise gear pumps.

Analysis of Dimensional Tolerances on Hydraulic and Acoustic Properties of a New Type of Prototypal Gear Pumps

Abstract: This study focuses on the construction of a prototype series of pumps. The technological capabilities of the entire series of gear pumps with a three-poly-involute outline were determined. We developed neural networks to analyze the dimensional tolerance and composition of the pump components and impact on the distribution for the constructed units. The most crucial dimensions to control were then determined—namely, dimensional and form tolerance were necessary—with a reduction in accuracy classification where it is less important. Measurements of acoustic quantities and of vibrations were also carried out. In conclusion, after positive verification, printed polyethylene wheels can be manufactured in greater, mass-produced quantities. Optimization techniques can then be applied, leading to reduced manufacturing costs and increased efficiency.

Gear Pump Bearings-Reverse Design of Journal Fluid Lubrication

Abstract: The sliding of the journal bearing of the gear adopts the traditional design method, showing the state of full fluid lubrication. However, this is not enough to support the pump as a whole to achieve more efficient operation. We need to use the creation of load capacity coefficients, optimized design to obtain parameters such as shaft diameter, width-to-diameter ratio, and execution clearance as the basis for the optimization model. For example, using the minimum oil film thickness and journal deflection as the objective function, the model is built with the help of reverse design thinking. Through innovative practice, it has been shown that the upper limit values of processing technology and leakage control can be obtained, and the diameter of the pump journal can reach a difference of more than two orders of magnitude compared with the original value. If we neglect the bearing capacity coefficient, the probability of tilting deformation of the bearing becomes smaller, and after the optimization of the curve, the overall design optimization has achieved good results.

Hydrostatic Actuator Drive Control with Pump Leakage Compensation

Abstract: The paper presents research of the hydraulic cylinder drive system equipped with gear pump driven by asynchronous motor fed by the frequency inverter using a developed method of pump leakage compensation (LPC) to control the flow. The pump parameters at various pressures and various angular speeds of the asynchronous motor, including in the speed range below the minimum recommended by the pump manufacturer, have been tested. The obtained pump characteristics showed the presence of two components of internal pump leakage - independent and dependent of pressure. The linear internal leakage model was developed for the pump. This model has been implemented to the verified model of the drive system of the variable ratio mechanism driven by a hydraulic cylinder - scissor lift. The pump flow correction algorithm has been added to the previously developed hydraulic cylinder speed control system. This correction was aimed at improving the mapping of the assumed speed of the hydraulic cylinder. The compensation block has been added to the hydrostatic drive of the scissor lift equipped with an open control system - developed in the LabView environment. Experimental tests confirmed the improvement in mapping of the hydraulic cylinder assumed speed regardless of its variable load resulting from the scissor system geometry and the weight of the load on the scissor lift platform. The developed leakage compensation system on the pump can be used in hydrostatic systems with fixed or variable ratio, regardless of the load on the hydraulic cylinder.

Analysis of the Causes of Driving Gear Shaft Fractures in Gear Pumps

Abstract: Multiple instances of driving gear shaft fractures in gear pumps have been found in real-life applications. The radial force in the gear pump was calculated to analyze and to identify the causes of fractures. Using the finite element analysis software Ansys, mechanical analysis of driving gear shaft was performed, stress and strain states of different structures were compared, and the impacts of jammed shaft and overload on the driving gear shaft were simulated. The hardness of the gear pump after heat treatment was measured by using a Vickers hardness tester, and its fractures were observed by a scanning electron microscope. The results showed that the maximum stress of the material in the vicinity of the undercut under normal conditions, which should not result in the driving gear shaft fracture. Jam, overload, or improper heat treatments are the main causes of driving gear shaft fractures, and the radial force is one of the reasons leading to the jam.

Experimental Characterization and Evaluation of the Vibroacoustic Field of Hydraulic Pumps: The Case of an External Gear Pump

Abstract: This paper presents the experimental characterization of the vibroacoustic fields and the evaluation of noise performances of hydraulic pumps. Research on hydraulic pump noise has traditionally focused on the fluid-borne noise sources, and very often the analyses of vibration and noise have been performed focusing on a few local points. This trend results in the lack of investigation on the overall behaviors of vibroacoustic fields of hydraulic pumps, and it has been one of the obstacles to understand the complete mechanisms of noise generation. Moreover, despite the existence of the ISO standards for the determination of noise levels, diverse metrics have been used for the evaluation of noise performances of the pumps, but the adequacy of these metrics has not been carefully examined. In this respect, this paper aims at introducing a way to characterize and interpret the measured vibroacoustic field and providing proper methods which are also capable of applying the ISO standards for the fair assessment of pump noise performances. For the characterization of the vibroacoustic field, operational deflection shapes (ODS) and corresponding radiated sound fields are visualized at harmonics of the pumping frequency by using a spectral analysis. Observations are made regarding the motions of the pump and its mounting plate and the resultant radiated noise, depending on the frequency, as well as their correlation. A numerical analysis using the Rayleigh integral equation is also performed to further investigate the contribution of the mounting plate motion on the noise radiation. For the evaluation of noise performance, two different units are tested at multiple operating conditions, and comparisons are made based on their measured sound power levels (SWLs) and sound pressure levels (SPLs). The results emphasize the importance of SWL measurement for the fair noise performance evaluation, and the two methods are proposed as practices to determine the minimum number of measurement points for practicability and to have reliable sound power determination for hydraulic pumps.

Assembly practical training production line for automatic gear pump

Abstract: The invention discloses an assembly practical training production line for an automatic gear pump, relates to a protection line for practical training, and specifically relates to a protection line for practically training and assembling an automatic gear pump model. The assembly practical training production line for the automatic gear pump sequentially comprises a station I, a station II, a station III and a station IV; the station I is a pump body assembly station; the station II is a gear assembly station; the station III is a cover plate assembly station; the station IV is a finished product assembly station; the assembly practical training production line for the automatic gear pump further comprises a control device; and the control device is respectively in data connection with thestation I, the station II, the station III and the station IV. The control device is an industrial computer, a PLC or a single chip microcomputer. The assembly practical training production line forthe automatic gear pump provided by the invention is sequentially assembled through the station I, the station II, the station III and the station IV.

Electro-hydraulic gyrator with good heat dissipation effect and adjusting function

Abstract: The invention relates to an electro-hydraulic gyrator with a good heat dissipation effect and an adjusting function The electro-hydraulic gyrator includes an oil storage tank, a motor, a gear pump, agear, a rack, an oil cylinder, a connection plate, two oil pipes and two pistons Heat dissipation mechanisms each include a rotating shaft, two first bearings, two rotating assemblies and a plurality of paddles An adjusting mechanism includes a supporting plate, an air bag, two adjusting assemblies and two inflatable assemblies According to the electro-hydraulic gyrator with the good heat dissipation effect and the adjusting function, air flow around the oil pipes is accelerated through the heat dissipation mechanisms, heat of the oil pipes is taken away, the function of heat dissipation is realized, and the situation that normal work is affected due to overheating of the oil temperature is avoided; and the adjusting mechanism drives the connection plate to move upward, so that the rack is moved in the direction close to the gear, the gap is reduced, and the situation that the transmission effect is affected due to large gap caused by excessive wear is avoided

Numerical analysis on the start behavior of rough journal bearings during the gear pump meshing cycle

Abstract: In this paper, the transient lubrication characteristics of hydrodynamic journal bearings during the external gear pump meshing cycle are studied. In the bearings lubrication calculation part, a nu...

Device for limiting number of people in closed occasion

Abstract: The invention provides a device for limiting the number of people in a closed occasion, and effectively solves the problem that no special flow limiting device exists in a key area in a traditional scenic spot, and potential safety hazards exist. According to the technical scheme, the device comprises a rectangular box, the left side and the right side in the box are each provided with an arresting device, each arresting device comprises a wire wheel, a rotary disc is arranged on the rear side of each wire wheel, and a stop lever is arranged at the upper end of the rear side of the box, and aconnecting rod is hinged on one end of each stop lever; a gear pump is arranged on a front side plate of the box; a first hydraulic cylinder is fixed in the box; a second hydraulic cylinder is arranged below the first hydraulic cylinder; the gear pump in the arresting device on the left side can pump a solution in the second hydraulic cylinder into the first hydraulic cylinder through a pipeline,a gear pump in the arresting device at the right side can feed a solution in the first hydraulic cylinder into the second hydraulic cylinder through a pipeline, a gear coaxial with a wire wheel is fixed to the rear side of the wire wheel, and a horizontal rack is fixed to the lower end of a piston rod in the second hydraulic cylinder; and movable plates are arranged at the lower ends of the two sides of the box, and one ends of the movable plates are connected with the wire wheels through ropes.

Discrete Optimization of a Gear Pump after Tooth Root Undercutting by Means of Multi-Dimensional Logic Functions

Abstract: In this paper, the optimization of a gear pump after tooth root undercutting has been investigated; this requires the volumetric, mechanical and total efficiencies of the pump to be calculated. Due to conflict in the existing model, the total efficiency is often calculated with the assumption that the other efficiencies have acceptable values. Multiple-dimensional logical functions are an additional independent method that can be used for the optimization of a pump.

Experimental Study on Critical Design of Electro-Hydrostatic Actuators Small in Size and Light in Weight

Abstract: Actuation systems for robots and other machines used in critical applications is an area that requires further research. In such applications, a machine works in a human environment and physically interacts with humans. Reliability and backdrivability are still insufficient in current systems. An electro-hydrostatic actuator has the potential advantage of high reliability by nature and high backdrivability in mechanical simplexity when it is designed to be small and light. This study provides a theoretical investigation of the methods for evaluating internal leaks and other mechanical losses, such as Coulomb and viscous friction, and experimentally evaluates two types (trochoid and involute gear) of prototyped hydraulic pumps.

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

Abstract: 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 fo...

Electro-hydraulic proportional control auxiliary system and engineering mechanical equipment

Abstract: The invention provides an electro-hydraulic proportional control auxiliary system and engineering mechanical equipment. The electro-hydraulic proportional control auxiliary system comprises an engine,a gear pump, an electro-hydraulic reversing valve, a control module and a rotating motor. The engine is connected with the gear pump; and the gear pump is connected with the rotating motor to drive the rotating motor to rotate. The electro-hydraulic reversing valve is arranged between the gear pump and the rotating motor; the control module is connected with the electro-hydraulic reversing valve;the control module can control the openness of the electro-hydraulic reversing valve to adjust the flow of the rotating motor; and the flow of the rotating motor can be precisely controlled as neededto realize refined operation so as to prolong the service life of the rotating motor.

Hydraulic system for AGV automatic braking

Abstract: The utility model discloses a hydraulic system for AGV automatic braking. The hydraulic system comprises a hydraulic control system and a braking device. The hydraulic control system comprises an oiltank, a motor, a gear pump, a valve, a pressure measuring tool, a pressure sensor and a pipeline. The brake device comprises a brake disc, a wheel flange, brake calipers, an axle bracket and a mounting bracket. The pressure sensor feeds back the current state to the hydraulic control system, then the hydraulic control system controls the pressure flow of oil in the pipeline through the valve, thebrake calipers are made to clamp the brake disc, and finally the functions of emergency braking, decelerated turning and the like of the AGV in the high-speed state are achieved. According to the utility model, the vehicle speed of the AGV can be adjusted in the driving process, the parking braking is completed, and the goods shelf is prevented from toppling over or losing stability when the AGV is braked and stopped in emergency.