| Wheel loaders belong to spade and transport machinery. They are mainly for bulk materials'spade work, transport, unloading and flatting operations, and also are able to mildly shovel rock and hard soil. If they were equipped with the corresponding equipment, they can also be used for earth moving, lifting, handling, such as steel and timber. Wheel loaders have fast operating speed, high efficiency and good mobility, light operation. In order to accelerate the construction speed, reduce labor intensity, improve quality, reduce costs, they play important roles. Wheel Loaders have been widely applied in the constructions, railways, highways, ports, mines and other economic sectors. The wheel loader is a major type of Mechanical engineering, as well as the an indispensable one of construction of modern mechanized construction.Wheel Loader dynamic weighing system is used for weighing the materials in the course of operation . Dynamic Weighing System generally consists of sensors, signal acquisition system, data processing and analysis system weight display and Print system. The basic principle is : pressure sensors, angle sensor and acceleration sensor measure work hydraulic system's cylinders'(mainly lift arm lifting cylinders)pressure lift arm's position angle and acceleration, data acquisition and processing system based on kinetic model calculated load weight, then display the print weight through output system.Advantages of dynamic weighing system : first, to ensure operational efficiency. Wheel loader dynamic weighing is in the course of work and do not need to stop Wheel loader, wheel loader completely keep normal operations; Second, the high precision weighing. Compare with the traditional line density measurement method of calculating the weight, accuracy greatly enhanced. Third, simple and cheap. Weighing system can be fixed on original wheel loader with the modular installation, easy and convenient. Compare with large dynamic weighing systems, Weighing system is carried by the wheel loader, and is not subject to space constraints, Meanwhile prices is low.This paper studies the core of Wheel loader dynamic weighing system, the equipment kinetic model. The author simplify the equipment, and give analysis of kinematics. On this basis, the author analyses the influence of the various factors to the model, and creates a dynamic model with a formula , the influence of the slope of the ground included in the model for the first time. Then aim at wheel loader's actual working conditions and operational characteristics, author designs using angle sensor location of the boom angle, and pressure sensors in the fuel tank and boom tanks to fight the dynamic pressure measurement programs, using a wheel Loader domestic production plants of a certain type wheel Loader for a lot of experiments. Finally, the dynamic measurement experimental results were compared with each other and to verify the theoretical analysis is correct.Device structure of wheel loader equipment, according to the number of different components can be divided into three, four, five, six and eight Linkages, on the import and export of steering rod is divided into whether the same is transferred and reverse linkage integrated link various agencies, Conversely six institutions work more advantages can ideal shovel equipped to meet operational requirements. Bucket tank separate action, the six agencies working to simplify the hinge four; Boom tank separate action, can be simplified to hinge six agencies. For a wheel Loader, various design dimensions are known, the use of the plural vector analysis of its campaign, available equipment to the points of the position, velocity and acceleration.Wheel loader equipment kinetic model. Loading the device as a whole, including boom, the arm, the stick and bucket and materials. The overall force, including tanks boom, the force of the fuel tank to struggle, the force of gravity. boom with its frame hinge point, the force of friction and ground slope on the impact. To boom with a frame hinge point of the center, according to a rigid body around a fixed pivot of the differential equation, can come up with other weight load capacity of the said expression. Design Dimensions obtained through inertia, and with angular acceleration sensor measuring acceleration, Measuring with angle sensor arm deployed position angle (slope of the ground prior measured) can be obtained by the load-weight.In order to study the fuel tank pressure with the boom lifting of the changes, the design of a dynamic experiment. Experimental measurement of dynamic pressure sensor using all the pressure tank, use of Hall proximity sensor boom position angle. Load test is divided into uniform load 1.4 tons, 2.8 tons, 4.2 tons, 2.1 tons of eccentric load situations. Various load were tested parking lifting boom, the racer lifting boom, static lifting boom, EQUAL static lifting boom several conditions.By stopping lifting boom, the racer lifting boom conditions of the various loading analysis can be compared to see : good experimental data to verify the theoretical analysis is correct. Said the group has found the situation boom lifting tank there is a big pressure fluctuations for sub-sampling and multi-point measurement for the average data collection methods, can improve dynamic weighing accuracy. 2 static condition, the fight to the fuel tank pressure data comparative analysis proved that the slope of the ground, to fight the tanks weigh the impact.With China's sustained and rapid economic growth, the level of industrialization improves continuously. In various fields with new technology application. Wheel loader as a major types of construction machinery , its technical level is rising. Dynamic weighing system enhances the use of the wheel Loader, with a simple, fast, high accuracy, low cost, ease of use and many other advantages, But wheel loaders equipped with only a very small number in the domestic. In summary, dynamic wheel loader weighing system in the future will have a vast space for development.
|
PDF Full Text Request