Xu Dong Pan

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.

Simulation Research on Effect of Diametral Clearance of Spool Valve to Valve Orifice Discharge Characteristic

This paper studies the effect of spool valve diametral clearance of electro-hydraulic servo valve on orifice discharge characteristic. To ensure that the freely sliding between spool and sleeve, there must be given diametral clearance between spool and sleeve, which will have an impact on valve orifice discharge characteristic, this paper first individually sets up a 3D models of clearance from 0 to 5 μm, opening value from 0 to 40 μm, then calculates each model’s discharge on the condition that valve orifice’s inlet and outlet differential pressure is constant, finally according to the result of the discharge plots the diametral clearance curve of spool valve. The quantitative numerical relationship of diametral clearance and spool valve characteristic index is given after doing the analysis, Finally, an experimental verification of the simulation results is to be done to prove the simulation results are correct and reliable. The research of this paper provides the basic guidelines for spool valve designing and testing.

Study on Fluid Process Measurement Technology

Process Measurement is a measuring method which is accompanied with process of the manufacture of work piece. This paper puts forward a new concept of fluid process measurement, and provides four types of fluid process measurements, which are, pressure pneumatic process measurement, flow pneumatic process measurement, pressure hydraulic process measurement, and flow hydraulic process measurement, and establishes the mathematical and physical modal for them. This paper also provides an example of the application of this measurement method. This measurement has a good prospect, because it can deal with the work pieces with high-precision, complex shape and which are hard to be measured in the machining process.

Design of Hydraulic Locking Mechanism Based on Material Friction

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.

Servo Valve Nozzle Fuzzy Clustering Analysis Pairing Algorithm

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.

The Research on Red Light Ranging Float Pneumoelectric Conversion Technology

This document explains how to transform an ordinary float-type pneumatic measuring instrument by adding a right lights sensor on it. Then we design a suitable float for it through the theoretical calculation and the simulation with Fluent. At last, the research do a series of experiments and by the experiments, its nonlinear error is less than the ordinary float-type pneumatic measuring instrument. So the whole instrument is feasible. The final purpose of designing the float-type pneumatic measuring instrument based on the red lights sensor is to measure the overlap of the valve core & sleeve of the slide valve.

Design of the Output Performance Test System of Permanent Magnet Linear Force Motor

Electrical energy directly converted into mechanical energy of linear motion by linear force motor, greatly enhancedthe rapid response ability and control precision of the feed system. The product quality of linear force motor can be effectively improved by design a performance test system of linear force motor. The paper designed a performance test system of linear force motor based on the Labview virtual instrument platform, and test project of linear force motor has been planned, the test method, the structure of the test device, power drive module, step motor load part, data acquisition and the software system all have been completed. The test system realized automatic and manual two different kinds of test methods, data acquisition and management and processing function and the good human-machine interface, the linear force motor dynamic and static parameter, including input current, output force and output displacement and the relationships between them have been tested.

Research on Control Algorithm of Electric Loading System

The disturbance torque which is caused by the interference of the motor position has observably impact on accuracy of the loading system. According to unstable loading channel and disturbance torque, this paper use a complex control algorithm of differential forward PID control and feed-forward compensation. At the end of this paper, the simulation analysis results show that the feed-forward compensation can observably eliminate the influence of the disturbance torque, and improve the accuracy of the loading system.

Mathematical Model and Characteristic Analysis of Electric Loading System

In this paper, a mathematical model of the loading system is established. The characteristics of the loading channel and disturbance channel are analyzed through this mathematical model. Analysis results show that the loading channel is unstable and disturbance torque leading the input command. It directly impact on the output torque, serious affect the systems loading precision. Characteristics of the loading system are analyzed, and the results show that stiffnesss effect on the loading system is twofold, should be considered at the same time. Reduce the systems moment of inertia is good for the characteristics of the loading system.

Automatic Measuring System of Servo Valve Overlap Value Based on Hydraulic Cylinder Switching Oil-Way

During the processing of the servo valve spool machining, the overlap of valve spools each edge should take zero grinding. The grinding processes including spool overlap test and grinding. In this paper, the authors used a new test method, which simulates working condition of servo valve. Hydraulic cylinder is used as the load of servo valve in this test method, and the hydraulic cylinder is in no-load operation. This test method realized the automatic switch of test valve, and it determined the amount of grinding through complete measuring four edges overlap values, furthermore, it realized measuring the total amount of overlap, thus reflect the flow characteristics of a valve. This is a new automatic method for measuring servo valve overlap.