Recently, a team led by Professor Hu Suyun from Hunan Radio and TV University (RTVU) was presented with Third Prize in the Scientific and Technological Progress Award for their success in developing an “automatic production line for the automotive motor rotor threading process”. Their work has filled a gap in automatic threading technology for electric motors in China, with the overall technology reaching an advanced international level.
Professor Hu Suyun (Right) Discussing Production Procedures with Company Leaders in the Workshop
The “automatic production line for the automotive motor rotor threading process” is a procedure designed to thread automotive starter rotors. It is made up of three pieces of equipment: a line-rolling machine, a winding machine, and a threader. In recent years, apart from a few individual producers of automobile components and parts that have purchased expensive automatic threading equipment from abroad, this process was largely done by hand with small molds, resulting in low productivity.
Research on automatic threading equipment supported by enterprise resources
After her graduation from Wuhan University of Technology in 1987, Professor Hu was assigned to Changsha Automotive Electric Factory to design non-standard equipment. At that time, the threading of automotive motor rotors was done manually with very low productivity and uneven product quality. In 2003, she started work at Hunan RTVU and was put in charge of declaring the programme of mechanical manufacturing and automation and later became the head teacher of the programme. Since she had kept in touch with her colleagues in the automotive electric factory, she had learned that Yu Shenchuan, her former colleague and classmate, had started Changsha Youjia Industrial Company, specializing in the research, development and production of automobile components and parts production line and non-standard equipment. Hu and Yu quickly became partners, and they began to discuss the research and development of, and market demand for, automatic threading equipment for electric motors.
In 2011, after four years of dedicated research, Professor Hu and her team made an initial breakthrough in their research and development of automatic electric motor threading equipment, which was then put into production in Youjia Company. Previously, 10 people were needed to complete this process, while the new equipment only requires one person. It costs RMB 5 million to import the same equipment from abroad, while Professor Hu’s equipment only costs RMB 1.1 million. Therefore, the automatic electric motor threading equipment saves both manpower and funds. Before long, several producers, including Changsha Hitachi Automotive Electric Company, Torch Automobile Group Co.,Ltd. and Shanghai Highly Electric Co., Ltd. purchased the equipment. According to incomplete statistics since 2011, the qualification rate of the processed products reached 99 percent in the three companies mentioned above, adding an output value of RMB 36.32 million and generating a profit tax of RMB 7.797 million. In addition to its use in the automatic threading of automotive motors, the technology can also be used in the automatic threading of motors for home appliances, and the shipping industry. It can also be used in the new energy field, showing promising application prospects.
Breakthroughs in key technologies
“The YJZX01 line-rolling machine is capable of adjusting the thickness of the pressed copper wires with the hand wheel of the spinning adjustment device, with a margin of error for thickness of 0. 01 mm. In the past, we had to purchase flat copper wires of different thickness to meet the needs of different product types, which led to wastage.” “The enameled copper wires are processed by the YJCX01 winding machine through edge cutting, paint removal, chamfer angle cutting, unifying the chamfer angles and mold deburring.” “The YJX01 threader can accurately set the angle and times of the splitting from different angles to achieve precise splitting only by fitting parameters on the control panel with the PLC programme and human-computer interface …” The above is taken from a user experience report by Hitachi Automotive Electric Company.
“This was no easy task”, said Professor Hu. During the course of research and development, “the winding machine has to cut the flat wires sent by the line rolling machine into specific lengths and sizes, and cut the edge and paint on both ends of the enameled copper wire according to the product requirements”. This was just one of the major problems encountered during the development of the technology. After the enameled copper wire is cut, the copper wire has to be completely smooth, otherwise the insulation paper will break and the product produced will become scrap. Therefore, it has become a major technological challenge to improve the quality of the cut surface of the copper wire and to ensure the smoothness of the copper wire surface. It took Professor Hu and her team nearly three years to develop molds for“precut parts for cutting the edge and paint”.
Another of the threader’s key technologies is the overall splitting and turning of the U wire set. After splitting and turning, the mechanical hand device pulls out the wires from the mold and inserts the wires in the slots of the rotor. The splitting and turning mold has to split and turn a complete set of U wires. The wires will rebound after they are split and turned at a certain angle, which fails the requirements of split angles; the wire set is easily deformed if the angle and force are not well controlled when the mechanical hand device pulls out the wires, making it impossible to insert the wires into the slots of the rotor. Problems like this were a constant puzzle for Professor Hu. However, she never gave up and after three years of hard work she managed to solve the problem.
Teachers have to go down to the frontline of enterprises
“Teachers have to go down to the frontline of enterprises to improve their own teaching level”. During the research and development of “the automatic production line for the threading process of automotive motor rotors”, Professor Hu encouraged her students to participate in the design and manufacturing of the components to develop their problem solving abilities. She often moved her class to the enterprise and held classes in the workshop. “This is a rare opportunity to establish such a close relationship with enterprises during the process of scientific research. Sometimes, the enterprises would ask technicians to give demonstrations to the students by specially starting the operation of the machine”, Professor Hu said, “Without integration with enterprises, we have no way of knowing how and where technology develops. Enterprises are always changing; only new innovations and technologies bring new users or customers. I have more confidence thanks to the knowledge and perspective I have gained from enterprises.”
In addition to the “automatic production line for threading process of automotive motor rotor”, Professor Hu has earned several other scientific achievements. In the next stage, she will organize the materials relevant to the research development of the equipment and apply the equipment in her teaching practice. Some components and parts of the scientific research equipment will be used in course design as source materials for the students to practice. Furthermore, a number of enterprise issues will be completed by the teachers and students together.
“Many people can’t imagine a woman taking up mechanical design and manufacturing as a career, but I’ve been doing it for years. I am really fond of the major and enjoy my work.” Professor Hu is still working hard in the field of mechanical manufacturing, ready to take up the next challenge.
By Hunan Radio and TV University