Research And Design On Automatic Assembling Bolts System For Fracture Splitting Crankcase Bearing Block Of Engine

The fracture-splitting technology is a new technical for processing section parts which has been developed since the beginning of the 1990s. It is a grand renovation to the traditional processing method. This new method is full of imagination and ingenuity, and first used in engine connecting rod machining. As it simplified structural design of bolt hole and whole process technology, the method has many advantages, such as less working processing, small equipment investment, low manufacture cost, good product quality, high assembly precision, great carrying capacity and so on.Along with the mature of the fracture-splitting technology of connecting rod of engines, many foreign companies dilated the research field in recent years. Crankcase bearing block of engine, Crank shaft flange, Cam disk, Strap, Bearing for printing machine are all produced by fracture splitting technology. Crankcase bearing block is one of the key parts of engine. It is difficult to cast and process in manufacturing. As fracture-splitting technology which changed the traditional method of separating processing of the bearing block and cap is used to process bearing block, the difficulties are solved. This technical got rid of the procedure of milling and complicated clamping device when processing the relevant faces. So Domestic and international researchers have paid a lot of attention on this technology. The investigation on this technology is on primary stage at home. After the research team of Jilin University have successfully produced the equipment for fracture-splitting connecting rod, they began to research on the field of fracture-splitting crankcase bearing block of engine. The team applied the patent "the method and equipment for facture splitting crankcase bearing block of engine" in 2005.The key items of the fracture splitting technology are automatic production of three core working procedure. They are machining of cracking notches, directed fracture separating and assembling bolts in required torque. Contents needed to be researched in this thesis are automatic assembling bolts system for fracture splitting crankcase bearing block. Being one of the key techniques of the fracture splitting technology, assembling bolts is upmost important to the quality of fracture splitting crankcase bearing block.During the fracture separating procedure, fracture splitting and restoration between bearing block and cap has been finished. But bolts have not been inserted. During the assembling bolts procedure, the first step is that the bolts must be fed automatically by the hopper. The bolts for jointing the cap and the crankcase bearing block together are fed to fixture of bearing block for inserting bolts by the hopper and feeding track. Secondly the manipulators for inserting bolts grasp the bolts into the bolt hole of bearing block automatically. Then the bearing block which have bolts are carried from working position of inserting bolts to assembling bolts. At last bolts are tightened in required torque by stable torque wrench. The chief technical difficulty is how to position all the bolts into the bolt hole in high precision. During the process of positioning, the manipulator must move steadily and its movement must be precise in order to insure the assembling quality of the next procedure. This question how to assure it is one of the key technical difficulties of fracture splitting bearing block. Furthermore, the equipment of feeding bolts must be chosen properly in order to bolts whose direction and position is wrong can be distinguished and winkled out. The manipulator of inserting bolts must insert all bolts into the bolt hole of bearing block simultaneously and accurately. The course is so complex and difficult that the fault ratio in this part of automatic product line is rather high. The fault ratio in the course of feeding and inserting bolts has influenced the automated production more or less. In order to solve above-mentioned difficulties, this thesis has research and design on automatic assembling bolts system for fracture splitting bearing block. The thesis includes three parts which are automatic feeding bolts system, the manipulator of inserting bolts and assembly system of stable torque wrench fastening. The main contents of the thesis are as follows:1. Based on deeply studying the structural character and function of all parts of feeding system, automatic feeding bolts system that can apply to different kinds of engine has been designed. It can meet with the desire of massive production. This feeding system has been jointed properly with the manipulator of inserting bolts in order that bolts can be inserted into the bolt hole automatically and exactly.2. The manipulator for carrying the bolts and insert them into the bolt holes is designed in the thesis. Considering two technical conditions, which is the high reduplicate movement precision during the inserting processing, and another is the applicability for different kinds of engine, certain adjusting device is provided and three-point grippers is chosen to grasp bolts. The three fingers move simultaneously so that the grippers can firm the centre automatic. The reasonable modular linear unit is set up in order to ensure the stability and precision of the procedure.3. Transport of electric numerical control torque wrench fastening is designed. In order to assure assembling quality and precision, the structure character and require of adjust torque wrench fastening has been emphasized and studied deeply. In this part stability and adjustable mode of fixture has been considered as a design emphasis.The automatic assembling bolts system for fracture splitting crankcase bearing block designed in this thesis can supply the gap of product lines imported from developed countries which can hardly changed the kind of engine. Because of advanced technology and well performance, it will have important meaning and play a positive role for accelerating technology renovation and promoting the industrialization of the crankcase bearing block fracture splitting technology in the domestic engine industry.