Key Engineering Materials Vol. 667

Abstract: The electro-hydraulic servo valve consists of many small hole parts such as nozzles, which are most important parts in a servo valve. The hydraulic oil flows into the nozzle and jets out from another side, the jet flow quality affects the performance of the valve. In order to study how the hydraulic oil influences the jet flow quality, a test system of the jet flow quality is developed.

Abstract: Spool valves are the main elements in electro-hydro servo valves. Hydraulic measurement is an important method for spool valve’s null cutting measuring process. Because of the flow pattern transition, the discharge coefficient is a variable. This phenomenon causes errors if we assume the discharge coefficient is a constant as we always do. In this paper, the variable discharge coefficient is considered to the submerged discharge equation, and the flow pattern error is defined. For improving the precision of overlap values measurements, a compensation method of flow pattern error is presented in this paper.

Abstract: This paper proposes a hydraulic measurement model for measuring the Laval nozzle throat diameter size. Based on measurement principle of liquid pressure – flowrate, we can get the size of Laval nozzle throat diameter by measuring the fluid flowrate through hydraulic measurement model at the fixed pressure. With good viscosity-temperature performance, low temperature performance and oxidation stability, UCBO aviation hydraulic oil is selected as the measuring medium. In the hydraulic measurement model, the diameter of the mandrel which can be regarded as gauge will directly affect the sensitivity of diameter measurement. Therefore we need to optimize the design of the mandrel of the hydraulic model.

Abstract: HLP type hydraulic oil has wide application in aerospace field. This paper discusses HLP type hydraulic oil’s performance. Then a new meso-scale hole measurement method is proposed base on HLP type hydraulic oil’ characteristic. Several groups of measurement experiments with different measuring parameter are done. The experiment results show that using HLP type hydraulic oil in meso-scale hole is suitable and effective.

Abstract: Common 13Cr steel is a kind of corrosion resisting material to be used as gas well pipe working under the situation of high pressure, high temperature and high H₂S, but it’s still destroyed in an undesirable period because of the poor working environment. To forecast its remaining useful life, parameters indicating the failure of gas well pipe with high pressure and high temperature and high H₂S are collected to form a dataset. The dataset is then transformed into fuzzy set and gas wells are classified according to it. Then the failure time forecast model of gas well pipe is established based on the well’s fuzzy set. Finally, 2 wells remaining life is calculated by the model. It is verified that the result got is in line with the actual situation. The model established is importantly meaningful for the safety production and the proper selection of gas well pipe.

Abstract: Asphalt paver is the main machinery and equipment for asphalt paving job, the performance of its automatic leveling control system is the key factors of the pavement. This paper analyzes the effect of deformed arm on paver leveling control system and the main factors influencing leveling system performance. On the basis of that, it proposes structural adjustment programs of paver leveling system to enhance its performance.

Abstract: Electro-hydraulic servo valve is the key component of an electro-hydraulic servo control system, and double nozzle flapper valve is the main type of electro-hydraulic servo valve. Nozzles are the important part of a double nozzle flapper valve, the pairing quality is directly related to the performance of the servo valve .Servo valve is of symmetrical structure, and the use of nozzles is also in pairs. The process of nozzles matched in pairs is called pairing process. Because the orifice diameter of the nozzle is only about 0.2 to 0.3 mm, it is difficult to pair with the method of direct measurements. Besides, as a kind of hydraulic components, nozzles are usually paired by flow rate measured under differential pressure. Two nozzles will be matched to a pair if their pressure-flow rate characteristic curve is within the allowed tolerance. To ensure the success rate of pairing, it usually needs a large number of machined nozzles to be sifted. According to the principle of clustering analysis, we propose a new paring algorithm which can match nozzles efficiently and automatically.

Abstract: Hydraulic cylinders are the actuators used in driving and bearing heavy loads. In normal conditions, it is required to bear load steadily for long time. Due to the inevitable internal leakage of traditional hydraulic cylinder, the strict conditions of the applications are always hard to meet. The materials selecting of cylinder and lock sleeve is very important on a new type of locking mechanism. This paper presents the design of hydraulic locking mechanism based on material friction properties. The strength, elasticity, temperature coefficient, and the factors such as friction coefficient are considered in the process of design. The choosing of materials of the cylinder and the lock sleeve are proposed based on different specific situations, such as steel and steel, steel and nodular cast iron, steel and bronze, steel and aluminum alloy. The paper take 45# steel cylinder body and QT50-5 lock sleeve as an example to illustrate the design process of locking mechanism.

Abstract: This paper introduces motor rotor blanking die design process through specific terms of the process of stamping all. Mould design process is for structural analysis and process analysis of the parts diagram, based on it to determine the technology methods, select the structure of the mould, and make a necessary calculation to determine stock layout and the size of the work part. And choose a suitable punching machine. Finally, choose the parts from the manual of mould.This design also includes the use of AutoCAD software mapping die assembly and major parts map using UG and Pro/E software for 3D solid modeling and animation design simulation process. In addition, the punch and die processing choose WEDM and Programming. So consider the structural design of WEDM of the specific methods to avoid the conflict between design and processing, and guarantee the production reasonable.

Abstract: Passive torque servo system (PTSS) is a key equipment in the hardware-in-the-loop experiment for the test of actuator performance. A novel mathematical model was obtained by analyzing the structure and working conditions of PTSS in this paper and the model was analyzed with the matlab software. PID controller was used to correct the actuator system and the result is effective. The disturbance torque was analyzed on different frequency of command signal, it was found that the disturbance torque increases, and with the phase ahead of the signal, but the amount of lead decreases with variation of frequency of command signal. Three components of the disturbance torque were obtained by theoretical analysis, and the reverse current compensation method was composed. It was found that the proportion of three parts of disturbance torque changed with increasing frequency of command signal and the reason of the variation was analyzed. Finally, the theoretical analysis of the construction of disturbance torque was correct by the comparison of the result of simulation.