Dong Xiang Shao

Study on Non-Burr & Sharp-Edge Protecting Grinding Method of Functional Edge

This paper researches on the formation mechanism of functional edge (e.g. throttle edge of servo valve’s valve core) during grinding process, and presents due to plastic deformation which is extruded by grinding wheel, burrs are appeared on the edge, and furthermore the edge becomes not sharp. This paper provides a non-burr & sharp-edge protecting grinding method which is named protection part method, used a protection part to protect the edge out of burrs and be sharp. Experimental data prove that utilizing protection part which is the same hardness with the processed part and an appropriate magnitude of interference parameter, this method can assure non-burr & sharp-edge protecting grinding of functional edge.

Development and Experimental Study of Magnetic Property for Servo Valve Torque Motor

Torque motor is an electrical-mechanical converter of servo valve, is bridge which connects the electrical devices and hydraulic devices, is one of key components of servo valve. The permanent magnet torque motor is studied in this paper. As key parameters of design of servo valve, the magnetic property of torque motor determines magnitude of the electromagnetic torque. At present, many manufactures of servo valve pays more attention on the test of integral servo valve. The design of torque motor also bases on experience, lacking of specialized tool for torque motor test. This paper described the principle of magnetic property of the test, developed a test system for magnetic characteristics, and established the relationship between the electromagnetic torque and current control current, and the relationship between output angular displacement and control current.

UCBO Hydraulic Oil and Application on Hydraulic Measurement for Laval Nozzle Throat Diameter

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.

Simulation and Analysis of Passive Torque Servo System

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.

HLP Type Hydraulic Oil in Meso-Scale Hole Measuring

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.

HLP Type Hydraulic Oil Analysis for Meso-Scale Hole Measurement

HLP type hydraulic oil has wide application in aerospace field. The existing measurement method of Laval nozzle throat diameter efficiency is low, and has the potential to cut parts surface. Therefore, a non-contact throat diameter measuring method based on the hydraulic oil is proposed. Then the flow field is simulated, and measurement parameters are calculated. The flow field analysis results show that this method is suitable for measuring Laval nozzle throat diameter.

Development and Experimental Study of Dynamic Characteristics for Servo Valve Torque Motor

Torque motor is the electrical - mechanical converter of servo valve, is the bridge connecting electrical devices and hydraulic devices, is one of the key elements of electro-hydraulic servo valve. The main object of study of this paper is moving iron permanent magnet torque motor. The dynamic characteristics of torque motor are the key parameter to measure the overall performance. At present, the research of most of manufacturers emphasize on the test of integral valve servo valve. Torque motor is also designed to mimic the structure and size of foreign-based valve, lacking of system understanding for characteristics of servo valve. Early in the design, people cannot effectively control the overall performance of the torque motor products. There is large performance difference with a larger group of torque motor, producing serious waste. This paper describes the principle of dynamic characteristics test, establishes a test system of dynamic characteristics for torque motor, accurately obtain nature frequency and bandwidth of torque motor on the test bench which we have established before.

Research on the Hot Stamping of Invar Based on Flexible Mould

This paper introduces the defect formation and compensation method of Invar during hot stamping with multi point flexible mould. In cylindrical and spherical, for example, through Solidworks 3-d modeling, using Dynaform to do forming numerical simulation, we study multi point hot stamping defects of thick Invar, mainly including indentation and rebound. Then we get the rules of indentation and rebound with thickness and curvature, compensate these defects and control the error within the requirements.

Research of Non-Contact Stiffness Measurement Technology

This article describes the elastic element of the servo valve, elaborates the definition of the stiffness of elastic element, analyzes the characteristics of existing rigidity measurement system, points out the limitations of the existing rigidity measurement system when it measures the large-stiffiness elastic element, utilizes a new measuring principle based on the existing stiffness test systems, uses the more accurate laser displacement measurement method to overcome the weaknesses of the existing stiffness test system, improves the measurement accuracy, makes stiffness measurements more accurate and promotes the stiffness measurement technology of the servo valve elastic element.

Improvement and Error Analysis of Spring Tube Stiffness Measurement

This article analyzes the deviation of existing stiffness measurement method and comes to the main components of the measurement error. Focus on the influence of the bending deformation all of aspects and contact deformation between the various links to the measurement accuracy. Establish the relationship between the actual deformation and the measured deformation to the spring tube through homogeneous coordinate transformation and finite element analysis, in order to identify the error sources impact on the measurement greatest, and improve the measure methods to against the main error source, eliminate the influence of the main error source to the stiffness measurement, then achieve the purpose of improving the measure accuracy.