Search

The thermo-hydraulic single regime operating generator is an innovative concept developed for the propulsion of road vehicles. The aim of the paper is to calculate the pressure losses in the hydraulic circuit of the single regime running thermo-hydraulic generator. The calculus is based on a modular approach proposed by. The pressure of the hydraulic liquid is determined by taking into consideration the local and the linear pressure losses in the system. These pressure losses are calculated applying classic formulas. This is important because the free piston displacement depends on the pressures acting on the side surfaces. The calculus algorithm is based on the constructive data of an experimental model.

The paper presents the operation of a hydraulic closed circuit equipped with a butterfly valve which can close with a step of 10o. Using four pressure transducers and one temperature transducer, the authors determined the volumetric flow rate, the average water velocity and the local pressure loss in the butterfly valve, the flow coefficient Kv and also the incipient cavitation coefficient. Recommendations for the disposal of the butterfly valve are made and conclusions are obtained regarding the range of opening degrees in which the butterfly valve is better to be used.

The paper presents an original pneumo-hydraulic system that controls the speed and the position of the actuated load by using a hydraulic circuit containing a hydraulic proportional throttle. A mathematical model of the solution is developed and numerical simulations are performed. The experimental results obtained on the built model confirm the theoretical ones.

In the present paper is presented a numerical simulation of an electro-hydro-mechanical system of adaptive transmission of mechanical power. This system is based on a hydraulic circuit consists of a hydraulic pump with constant flow and a hydraulic motor with variable flow ordered so that the pressure in the circuit to remain constant. For a variation of the ramp and step signal sources of loads, are presented the main features of operation of adaptive transmission. Analysis of dynamic stability of mechanical transmission is made through the linear analysis with Bode diagrams. Simulation of transmission operation is performed with AMESim.

In accordance to the drawback of amphibious vehicle's low speed in water, a new kind of folding mechanism based on double wishbone suspension is proposed. Referring to the working conditions of the wheel lifted mechanism, the hydraulic circuit, which provides with the functions of pressure limiting, locked and pressure retaining, is designed to ensure the accuracy of wheel lifted and the driving safety. The appropriate hydraulic cylinders, hydraulic components and auxiliary components are chosen due to the hydraulic system load and the maximum flow rate.

Double-column vehicle lift is a lifting equipment commonly used in auto repair and maintenance units, which is widely applied to the repair and maintenance of small vehicles such as cars. The design is a double-column vehicle lift driven by hydraulic. It mainly consists of lifting device, synchronous drive, column and bracket arm. The hydraulic circuit of hydraulic lifting device is designed. Currently, the articles concerning solidworks in the design of hydraulic drive lift only focus on unilateral appliance. When it comes to the design of the system, most of them concentrate on part modeling, virtual assembly, finite element analysis of parts ,etc, or a partial function of certain lifting machine. Seldom of them make a systematic research concerning motion stimulation. This paper, however, makes a three-dimensional virtual modeling for the lifting machine by the use of solidworks. In addition, it makes a structure verification of lift with assembly and motion simulation.

In this paper, Sichuan Bonny provided excavator experimental as a platform ,to testing the efficiency of various energy-saving hydraulic circuit. Based on the original hydraulic system design and adding new energy recovery system, observing the energy saving effect. Summarizes the large excavator hydraulic system common energy problems, deal with the problems from different aspects of hydraulic energy-saving technology describes the present state of hydraulic energy-saving technologies , and described the development trend of hydraulic energy.So that allows people to comprehensive understanding of this technology, to promote this technology popularization and application.

A Hydraulic circuit is a group of components such as pumps, actuators, and control valves so arranged that they will perform a useful task. When analyzing or designing a hydraulic circuit, the following three important considerations must be taken into account.Safety of operation,Performance of desired function, Efficiency of operation.It is very important for the fluid power ( Hydraulics and Pneumatics ) designer to have a working knowledge of components and how they operate in a circuit. Hydraulic circuits are developed through the use of graphical symbols for all components. Keywords: damper,hydraulic circuit

In order to meet the demand of hydraulic experiment teaching in universities, base on the analysis of the function of virtual hydraulic experimental system, the main research contents、 system scheme and key technology are determined. Three-dimensional model of the hydraulic components are established. Working principle of hydraulic component is displayed. The action process and the performance of the hydraulic circuit are simulated. A virtual hydraulic experimental system with its own characteristics is built. The virtual experiment system is not only suitable for classroom teaching but also suitable for the experimental teaching and learning activeness of students is enhanced by using the system.

This paper presents a new MW wind turbine yaw hydraulic system,and describes the working principle of the hydraulic system,derives kinetic equations of the electromagnetic proportional valve and the motor in the hydraulic circuit,uses AMEsim to establish a simulation model of the electromagnetic proportional valve control motor hydraulic system,sets parameters of main elements of the model,and simulates.given under the input current signal action,derives yaw motor shaft speed and time graphics,and analysis.

This paper reports the simulation and experimental results of a type of widely used load control valve. The investigated load control valve is usually applied to the mobile crane booming hydraulic circuit. It is used to balance the overrunning load due to gravity and to modulate the flow of oil when lowering the load. The load control valve has a significant influence on the performance of mobile crane booming system. A simulation model of the load control valve is established based on AMESim, moreover, a bench-test is conducted to evaluate the performance of the load control valve. The simulation results and the experiment data agree well and both results show a good performance of the valve. Further study of the effect and the inner principle of the key design parameters of the load control valve are also presented.

In order to improve the automation level of wrecker, fuzzy PID controller for the uprighting was proposed. First, the uprighting model was built in this article. Then, the hydraulic circuit of wrecker uprighting system was built in AMESim. Furthermore, the fuzzy PID controller and the conventional PID controller were simulated respectively in Matlab\Simulink software based on this model. Simulation results show that the fuzzy PID controller has faster step response speed and smaller overshoot than that of the conventional PID controller. The uprighting can be accomplished automatically and smoothly by virtue of the fuzzy PID controller.

As is known to all, domestic productions of injection molding machine are huge and exported to all over the world. However, the production can only occupy the low-end markets because of its high-energy consumption and low molding precision. Besides the problems of mechanical components, the main reason led to such results lie in the its too backward hydraulic system. By comparing domestic traditional hydraulic system with foreign new hydraulic servo system, this paper focuses on the analysis of the characteristics of foreign new hydraulic servo system and verify the results by experiments based on the upper two different hydraulic system. Through this paper hopefully can it provide some practical directs to the design of domestic new hydraulic system.

Noise is one of the common faults in hydraulic system. The correct analysis and deal with the noise will make for the normal operation and optimization of the system. In view of the noise of a new self-propelled transporter suspension hydraulic system produced in the debugging process of the heavy load lifting when suspension falling, by means of mechanism analysis, modeling and simulation analysis of the suspension hydraulic system, finding out the noise comes from the hydraulic component of system with SV type pilot check valve; The noise fault is caused by the improper circuit design of hydraulic system, the feasibility of the using the SL type pilot check valve to eliminate suspension hydraulic system noise proved by the simulation analysis, in the field test of the improved suspension hydraulic system, the suspension falling gentle and noise elimination, which shows that the analysis and simulation model is correct; Through the comparison and analysis on the SV type and SL type kinds of pilot check valve on the reasonable application in the hydraulic circuit isolation, that provides a theoretical basis for the correct selection two kinds of pilot check valve.

The hydraulic drive valve intelligent control system was discussed. Two grades, the field cell and the remote control cell, were used in the distributed control system. The communications of the system were implemented by Controller Area Network (CAN). At the first grade, single-chip microcomputer (SCM) acted as the control chip. The sampling pressure signal in pipeline was transformed into the output digital control signal by the controller. The digital direction valve acted as a transformation unit which converts the electric signal to mechanical action in the hydraulic circuit. The control process was realized by the digital signal directly acting on the step electrical motor. At the second grade, the industrial-control computer with a favorable man-machine conversation interface was used to realize monitor function.

Focusing on PET perform molding features, working principles of MA5300 Injection Molding Machine’s clamping unit’s hydraulic system has been analyzed in this paper. Based on previous hydraulic system, magnetic exchange valve has been added on the demoulding hydraulic circuit, demolding speed has been fastened; energy accumulator has been added on the control circuit so as to stabilize controlled oil-source, improve time of opening and clamping mould and response speed. In addition, common one-way valve in core oil circuit is replaced with hydraulic control one-way valve, in order to realize pressure maintaining function; hydraulic insurance structure is changed into inner circulation, and two-way cartridge valve is used as security valve, so as to realize faster response, and largely improved equipment security. Through adopting common hydraulic components, under the premise of limited increasing cost, the injection molding cycle for PET perform product has been reduced, and enterprise’s productivity has been improved.

The fault detection and diagnosis system, which uses dedicated interface adapter unit and PXI interface modules to perform signal excitation and parameter testing, is introduced in this paper. Its firmware consists of PXI-bus control computer, display control unit, dedicated interface adapter unit, connection cable and power supply unit. The dedicated interface adapter unit (IAU) is the core of hardware platform, and is composed of chassis, I2C-bus data acquisition board, adapter and military aviation sockets. It carries out analog to digital, digital to analog, digital I/O transformation as well as serial communication and CAN-bus communication. The software of the fault detection system is of hierarchical modular structure with integration of system management control, fault detection and circuit hardware driver modules together with repair and diagnosis database. The software provides functions of human-machine interaction, equipment fault detection, fault diagnosis and analysis, repair guidance and data storage. Therefore, this system can implement fault detection of hydraulic excavator on replaceable circuit board and block of the hydraulic system or electrical system. And it can help equipment repairmen and operator perform quick repairs and maintenance to the electrical system and hydraulic circuit of the excavator.

The brake safety is very important for passenger car development. Quick designing and matching brake system play an important role in automobile OEM. This paper presents a characteristic model for OEM to develop brake system by using of the features of subsystem or components. The model is a proper model because the structure parameters are not necessary. A brake pedal mechanics model is used to describe the relation of the input force and output force. The vacuum booster and master cylinder are modeled as a look-up table model. The hydraulic circuit model takes mainly account of the expansion and loss of hydraulic. After comparing the simulation data and test data, the conclusion that the model is accuracy can be drawn

This paper introduces the dynamics model and mathematical characteristics of the constant difference of overflowing pressure with computerized simulation by power bond graph of the fixed differential relief valve hydraulic system on simplified vertical planetary internal grinder, which puts forth proposals to design hydraulic circuit or component. Simulation shows that, when the load changes more than 50%, the speed of cylinder piston changes less than 0.31%, and the efficiency of the hydraulic system has also been greatly improved, which matches the experiments. It makes certain reference to the design of the hydraulic system in which the load changes large.

This paper proposed a novel mechanism for an unmanned electric vehicle with four-wheel independent driving (4WID), independent steering (4WIS), independent suspending and independent braking. This unmanned electric vehicle adopted the technologies of driving by wire, steering by wire and braking by wire. Which improved the maneuverability of the vehicle greatly and made it achieving straight, oblique, lateral movement, zero radius turning and other movement patterns. Detailed implementation mechanism and virtual prototype of the vehicle were given in this paper. The hydraulic circuit schematic diagram and control method of the braking system were given also.

A type of hydraulic pollutant decontaminating equipment was made in this paper. The decontamination and maintenance means were studied. The circulating decontaminating method was put forward and developed by modularized technique. The hardware of the decontaminating equipment was implemented with single-chip microcomputer and integrated circuit technology. The controlling application program integrated with fuzzy logic and reasoning function was developed. The practical use showed that the decontaminating equipment could be used in the maintenance of hydraulic circuit of bulldozer as well as the other engineering machinery, therefore realizing the quick decontamination and cleaning of hydraulic component and oil on-line purifying.