Hydraulic Part Research Articles

Research on Friction Hot Forming Technology of Hydraulic Cylinder

Hydraulic parts with three sealing devices always leak in use, absorber and air spring for example. Hydraulic cylinder can be sealed by itself if friction hot forming technology is adopted on hydraulic cylinder at both ends. By going through the technology, two sealing devices of hydraulic parts are saved, the leak of hydraulic parts is avoided, the rigidity of hydraulic parts is enhanced, the structure of hydraulic parts is optimized and the service life of hydraulic parts is increased.

Research on Disassembling Equipment for Construction Machinery Hydraulic Cylinder

Construction machinery hydraulic cylinder is usually discarded after service cycle. The residual value of discarded products can be recycled greatly by remanufacturing. Disassembly and assembly is the key process in hydraulic cylinder remanufacturing. The construction machinery hydraulic cylinder disassembly and assembly equipment is developed. Hydraulic power is adopted in this equipment. The clamping, positioning of cylinder tube is realized by hydraulic clamping mechanism automatically. The piston component pulling out or into cylinder tube is realized by hydraulic working mechanism automatically. This equipment has been applied successfully in the project of "key technology and equipment for construction machinery parts remanufacturing" in a research institute. The results indicate that the application of this equipment will not only increase the automaticity and efficiency remarkably, but also reduce the damage to hydraulic cylinder key part greatly.

Hydraulic Parts Designed for Bulky Goods Hydraulic Jacking Subsystem

In this paper, the major design is the jacking of bulky goods, jacking subsystem of translation system and traction cylinder in translation subsystem. The control of hydraulic system makes bulky goods reach a height, which are drawn by the traction hydraulic cylinder on anchor or sliding load car to load or unload the ship. This equipment can effectively reduce the transportation cost and it can be used to unload a variety of bulky goods.

The Research and Practice of the Hydraulic Parts Assembly Three-Dimensional Animation Simulation

This paper introduces the three dimensional animation to simulate the CBKI gear pump assembly procedure with three dimensional manufacture software 3DMAX, AUTOCAD2000 and AE in which AUTOCAD2000 is used to create the gear pump line, 3DMAX is for modeling and AE is used to create the animation and post-processing. This paper mainly focuses on the scheme of the gear pump in the assembly which is from the design and manufacture to the final performance.

A hybrid actuator modelling and hysteresis effect identification in camless internal combustion engines control

This paper presents a hybrid actuator composed by a piezo and a hydraulic part. Moreover, a cascade PI-PID-PI control structure for camless engine motor applications is considered. The idea of this contribution is using the advantages of both: the high precision of the piezo and the force of the hydraulic part. Piezoelectric actuators (PEAs) are mostly used for precision positioning, despite PEAs’ non-linearities, such as saturations, hysteresis and creep. In the control problem these kinds of non-linearities must be taken into consideration. The Preisach dynamic model of the PEA with the above mentioned non-linearities is considered. In particular, the hysteresis effect is considered and a model with a switching function is used also for the controller design. Simulations and measured results are presented.

Thermal-hydraulic Modeling and Simulation of the Hydraulic System based on the Electro-hydrostatic Actuator

Electro-hydrostatic actuator (EHA) was a typical power-by-wire (PBW) actuator, which was widely-used in large commercial aircrafts, such as Airbus A380. The electro-hydrostatic actuator(EHA) had the advantages of small sizes, light weight, high power density, high reliability and maintainability. With the application of EHA in large commercial airplanes, the airworthiness certification of EHA became an new problem. The precondition of the airworthiness certification of EHA was to understand its operating principle and characteristic. Because of no centralized hydraulic oil tank and short cycle oil circuit, the temperature-rise of the hydraulic system in EHA always kept high during operation. Therefore, it was important to build the thermal-hydraulic models of the hydraulic system in EHA, and to do the thermal analysis of the EHA by this model. In this paper, a lumped-parameter thermal-hydraulic model of the hydraulic part in EHA was proposed. The model was built based on the detailed analysis of the heat transfer of the hydraulic part in EHA. By the simulation of a practical system and the comparison with the traditional hydraulic system, the accuracy and practicality of this model was verified.

Digital Control of a Camless Engine Using Lyapunov Approach with Backward Euler Approximation

In this paper a modelling of a hybrid actuator is proposed. The hybrid actuator consists of a piezo, a mechanical and a hydraulic ratio displacement. This paper deals with a hybrid actuator composed by a piezo, and a hydraulic part controlled using a regulator for camless engine motor applications. The discrete control law is derived using the well-known Backward Euler method. An analysis of the Backward and Forward Euler method is also presented. Simulations with real data are shown.

Research on Failure Analysis and Maintenance Policy for Machine Tools

Machining tools are the main equipment for metal machining and consist of mechanical parts, electrical parts and hydraulic parts, and so on. In order to reduce the failures and improve the level of machine tools reliability, the paper firstly performs the failure analysis by the statistical method. Then the failure trends for the key parts of machining center are given using the power law process. In contrast with the usual method, which optimizes the maintenance under the repair costs, an optimization approach of maintenance is presented under the reliability constraints for machining center that used in a northeast manufacturing plant of China. The proposed analysis process could be a useful tool to assess the reliability and optimize the machine tools maintenance policy.

Hydraulic Motor Driving Variable-Pitch System for Wind Turbine

The present hydraulic variable-pitch mechanism of wind turbine uses three hydraulic cylinders to drive three crank and connecting rod mechanisms respectively; the blades are moved with the cranks. The hydraulic variable-pitch mechanism has complex structure, occupies a lot of space and its maintenance is trouble. In order to make up for the shortcomings of hydraulic cylinder variable-pitch system, the present hydraulic variable-pitch mechanism should be changed as follows: hydraulic motors are used to drive gears; gears drive blades; the electro-hydraulic proportional valves are used to control hydraulic motors. The hydraulic control part and electrical control part of variable-pitch system is redesigned. The new variable-pitch system is called hydraulic motor driving variable-pitch system. The new variable-pitch system meets the control requirements of blade pitch, makes the structure simple and its application effect is perfect. DOI: http://dx.doi.org/10.11591/telkomnika.v11i11.3494 Full Text: PDF

A Fast Building and Effective Hydraulic Pediatric Mock Circulatory System for the Evaluation of a Left Ventricular Assist Device

A mock circulatory system (MCS) has been proven a useful tool in the development of a ventricular assist device. Nowadays a MCS aimed at the evaluation of pediatric blood pumps, which require many different considerations compared with that of adults, has become an urgent need. This article presents the details on how the dynamic process of the left ventricle, which is described in terms of the pressure-volume loop (P-V loop), and the properties of the circulation such as compliance and resistance are simulated by hydraulic elements. A simple control method is introduced to reproduce the physiological afterload and preload sensitivities of the mock ventricle for the first time. Hemodynamic performance of the system is obtained by medical sensors to validate the similarity of the device to the native cardiovascular system. The actual sensitivities of the mock ventricle are obtained intuitively from the changes of the P-V loops. The aortic input impedance of the MCS is also obtained and compared with the data from previous medical reports. At last a pediatric left ventricular assist device (LVAD) prototype is introduced for testing to further verify the effectiveness of the MCS. The experimental results indicate that this pediatric MCS is capable of reproducing basic hemodynamic characteristics of a child in both normal and pathological conditions and it is sufficient for testing a pediatric LVAD. Besides, most components constituting the main hydraulic part of this MCS are inexpensive off-the-shelf products, making the MCS easy and fast to build.

Research into Cleaning and Suppression Equipment to Improve Reliability of Hydraulic System

Modern weapons are usually power-driven by hydraulic system, The reliability of hydraulic systems restricts the reliability of weapons. The research elaborated in this paper is focused on cleaning and suppression equipment, with the aim of implementing a thorough cleaning and maintaining of hydraulic system pipes and checking the pressure. Pipe cleaning and suppression is an essential step to guarantee the reliability of hydraulic system and the service life of hydraulic parts, thus improving the reliability of weapons.

Influence of Blade Number on the Performance and Pressure Pulsations in a Pump Used as a Turbine

The rotor-stator interaction of a rotating impeller and a stationary volute could cause strong pressure pulsations and generate flow induced noise and vibration in a pump used as a turbine (PAT). Blade number is one of the main geometric parameters of the impeller. In this paper, a numerical investigation of the PAT’s unsteady pressure field with different blade numbers was performed. The accuracy of global performance prediction by computational fluid dynamics (CFD) was first verified through comparison between numerical and experimental results. Unsteady pressure fields of the PAT with different blade numbers were simulated, and the pulsations were extracted at various locations covering the PAT’s three main hydraulic parts. A detailed analysis of the unsteady pressure field distributions within the PAT’s control volume and comparison of unsteady pressure difference caused by the increase of blade number were performed. The transient flow results provided the unsteady pressure distribution within PAT and showed that increasing the blade number could effectively reduce the amplitude of pressure pulsations. Finally, unsteady pressure field tests were performed and some unsteady results obtained by unsteady field analysis were validated.

Development of Pipe Structure Frame for CNC Lathe – Adaptation of Thermal Displacement Control

The miniaturization of many machine parts for machine tools is desired for the purpose of effective utilization of space, energy saving, and realization of desktop factory. To develop a compact and miniaturized NC machine tool, new downsized small parts such as hydraulic parts, pneumatic parts, electric parts and mechanical parts must be developed. These parts are not always satisfied for the practical usage in the present industrial level. Therefore, in spite of many requirements toward the miniaturization of the machine tool from the market, the miniaturized NC machine tool has not been put to practical use. The old-style structure of machine tools is one of the reasons of obstacle to solve this problem. We have proposed a newly developed ultra small size CNC lathe by using the pipe frame structure. The heat transfer between pipe elements and connecting block is affected strongly to the axial displacement. Therefore, the heat transfer between pipes can be insulated by the heat control on the connecting block. The thermal displacement control is realized by using the Peltier devices set on the connecting block. The results on the thermal displacement control of this structure and the effects on the cutting results are reported.

The Construction of the Management System of CNC Milling Parameters

CNC Milling Process for the complex characteristics, in order to solve how to quickly and effectively to provide a reasonable and optimal machining parameters of CNC milling process for technologist. The paper takes horizontal machining center DMC60H as a test platform and technological data of shell aluminum alloy hydraulic aircraft engine parts as a study. the paper establish management system of CNC milling parameters which was suitable for machinery manufacturing enterprises. The results showed that: The established parameters of CNC milling system can be better management of various CNC milling technology to effectively manage information and improve the CNC milling process information efficiency, has certain promotion effect to the production of the numerical control milling processing and the development of the manufacturing enterprises.

Hydraulic and Statistical Analyses of Design Emission Uniformity of Trickle Irrigation Systems

AbstractThe important evaluation parameter in trickle irrigation is emission uniformity. There are two different methods to calculate emission uniformity; (1) field evaluation for the subunit and (2) using theoretical formulas to calculate emission uniformity during the design period. Emission uniformity is usually divided into two parts, namely, manufacturing, EUm, and hydraulics emission uniformity, EUh. The global emission uniformity is the product of these two parts. Previously, a formula was developed to predict the manufacturing emission uniformity by assuming that when the emitter is tested at a given head, emitter discharges are normally distributed around their mean. This assumption did not apply well to the tested emitters. In this research, the manufacturing part was expressed in terms of the statistical characteristics of the distribution of emitter discharges when tested at a given pressure head. The hydraulic part of emission uniformity, EUh, was expressed in terms of the hydraulic character...

Numerical Investigations of Solid-Liquid Two-Phase Turbulent Flows through Francis Turbine

This work is to investigate solid-liquid flows inside entire passage of a large Francis turbine unit and a modified algebraic model is proposed to take the solid-phase turbulent viscosity into consideration based on realizable turbulence model for the liquid phase and further development of the commercial CFD software. The energy conversion between the pressure and velocity, and the sedimentation distribution characteristics around all the hydraulic parts are simulated. The calculated velocity and sedimentation concentration distributions inside the runner are not uniform due to the effect of the centrifugal and Coriolis force. In addition, the calculated eccentric vortex rope in the draft tube causes vortex cavitation and vibration to the turbine unit, which leads to the eccentric sedimentation distribution. The simulation results (i.e., the mixture pressure, velocity and sedimentation distributions) are in good agreement with the natural rule, suggesting that the simulation strategies are capable to handle two-phase flows over complex geometries. The computational results can provide the useful information for hydraulic turbine designs. Future work will focus on the optimizations of hydraulic impeller designs using simulated results.

Research on Hydraulic Self-Enhancement Technology of Fracturing Pump’s Valve Box

It is very important to process acid and fracturing treatment in oil field to improve permeability. The fracturing pump is one of the key equipment for Acid and fracturing treatment. The valve box of fracturing pump is fundamental, costly and wearing parts. Based on the data from domestic and abroad, the life of the valve box is short. Fatigue cracks caused by alternating stress and erosion account for the most invalidation of the valve box. Only increasing structural size and improving material property are not efficient to prolong service life. Related studies show that hydraulic self-enhancement technology is an effective method and it is used widely to improve service life of fracturing pump’s hydraulic parts. Here hydraulic self-enhancement process was simulated by finite element method and 600 Horse Power fracturing pump was studied. The optimal self-enhancement pressure and loading-unloading treatment method are suggested. This study offers a method to found valve box's production technics by hydraulic self-enhancement technology.

A Robust Cascade Sliding Mode Control for a Hybrid Piezo-Hydraulic Actuator in Camless Internal Combustion Engines

This paper deals with a hybrid actuator composed by a piezo and a hydraulic part and with a cascade sliding mode control structure for camless engine motor applications. The idea is to use the advantages of both, the high precision of the piezo and the force of the hydraulic part. In fact, piezoelectric actuators (PEAs) are commonly used for precision positionings, despite PEAs present nonlinearities, such as hysteresis, saturations, and creep. In the control problem such nonlinearities must be taken into account. In this paper the Preisach dynamic model of the piezo actuator with the above mentioned nonlinearities is considered. The control structure consists of two feedforward controllers and two cascade sliding mode ones. The robustness of the proposed scheme consists of the fact that the sliding control structure is independent of the dynamic model of the controlled system. Simulations with real data are shown.

Automated Model-based FMEA of a Braking System

This paper presents work on model-based automation of failure-modes-and-effects analysis (FMEA) applied to the hydraulic part of a vehicle braking system. The FMEA task and the application problem are briefly described, and the foundations for automating the task based on a (compositional) system model are outlined. The essential parts of models of hydraulic components suitable to generate the predictions needed for the FMEA are introduced. These models are based on constraints, rather than simulation, that capture the dynamic response of the systems to an initial situation, based on one global integration step and determine deviations from nominal functionality of the device. We also present the FMEA results based on this model.

On the Issue of Development of Replacement Hydraulic Parts for Oil-Trunk Pipeline Pumps

The paper deals with some issues of designing replacement hydraulic parts for flow rates of 0.6 Qn and 0.7 Qn comprising a replacement impeller and a guide vanes fitted in the double volute standard pump with the purpose of enhancing its efficiency and reliability. High efficiency has been obtained in the pump equipped with the replacement hydraulic parts at the low NPSH required.