Study On The Optimization Design Of Hydraulic Torque Wrenches And Improvement Project Of Hydraulic Torque Meter

As an assembly tool of the big diameter bolts, hydraulic torque wrenches have many advantages, such as big output torque, easy operation, being able to be used conveniently in the incommodious room, and comparatively precise control of the magnitude of torque. It seems very important to large infrastructure and mechanical and electrical equipments where large numbers of big diameter bolts are used, especially to the heavy-duty machine equipments which receive load and strong impulsive liberation. The joining quality of bolts will affect directly reliability and service life of equipments and structures. Although it has been applied widely in installation disassembly and servicing of many important bolts joins in many industries, such as metallurgy, machine, electric power, chemistry, railroad, shipbuilding, bridge, boiler, etc, there are still a lot to be improved with hydraulic torque wrenches. The most important two are low output torque precision and low work efficiency. In the design of the executing mechanism of hydraulic wrench, researchers mostly refer to existing production at home and abroad and make some improvement on them according to experience. The method is called experience analogy method. But the number of error and trial in the calculation work is large and it is not easy to find out optimum project by using this method. After deep analyzing and researching on the operating principle of the executing mechanism of hydraulic wrench and the existent shortcoming, a study on optimization design of the executing mechanism is developed. The modern optimization design method is used. At the same time, a study on the operating principle of torque meter is given. For the shortcoming of torque meter, the improvement project of mechanical torque meter and the design project of the digital torque meter are presented. The research work and conclusion are given as follows. According to the two shortcomings of low output torque precision and work efficiency, after deep researching on the operating principle of the executing mechanism of hydraulic wrench, the concept of mechanism precision is brought forward. The evaluating expression is given. The formulas of the swinging angle and the torque precision of the mechanism and relation expression between them are presented. The theoretic foundation is offered to the design of executing mechanism of hydraulic torque wrench. In the design of hydraulic torque wrench, optimization design method is first presented. The optimization design mathematical model of the executing mechanism of hydraulic torque wrench based on torque precision is established. In the course of optimizing solving, penalty function method and Powell method that is used to solve the multidimensional and abandoned optimizing question are applied. The optimization procedure is designed by the means of C language. The optimization procedure of the executing mechanism of hydraulic torque wrench is integrated by means of Visual C++. The design example is given. The result shows that optimizing method has many advantages. After analysis on the shortcoming of hydraulic torque meter, the improvement project for the mechanical torque meter is presented. Digital meter will be a trend with the development and generalization of sensor and digital display technology. Digital instruments have many inapproachable advantages. So in the paper, the design project of digital torque meter is presented.