Study On Explosion-proof Motor And Power-supply For Coal-mine Detecting Robots

The underground environment of coal mine is very complex and changeable, which usually has dangerous situations, so, using remote controlling robots to detect underground environment is an urgent need for coal mine safe production or disaster relief. Mobile underground environment detecting robots are adopted with high speed internal rotor brush-less DC motors as power element. Considering the anti-explosion requirements of coal mine environmental, the motor is mostly encapsulated in the flameproof enclosure. The motor power outputs from a rotating shaft type flameproof joint, however it has heat dissipation problems because of the encapsulation. And the torque of this type motor is so small that it needs a reducing mechanism to amplify the torque. But the reducing mechanism causes power loss, which reduces the effective power of the robot dynamic system.The outer rotor type brush-less DC motor is a kind of direct driving motor. With many advantages, like simple structure, convenient speed regulation and high efficiency, it has been successfully applied to many civil light vehicle dynamic systems. This thesis launches the research from the power and power-supply modules of underground coal-mine detecting robots, comes up with the concept of an explosion-proof hub motor for underground coal-mine detecting robots, and carries out related trail-manufacture works.With reference to the explosion-proof national standard GB 3836-2010, this thesis introduced the theory of compound type explosion-proof and its applications and decided to adopt flameproof explosion-proof method, and put forward a kind of installation structure with flameproof screw, also described the advantages of explosion-proof hub motor.On the basis of underground environment detecting robot trial design standard, the basic performance parameters of explosion-proof hub motor is determined. Developed the motor stator windings, and tested the performance, the test results are explained and analyzed. This thesis developed a low voltage and high power driver, set up the motor control circuit, tested the motor control system on field. Completed the design of power supply system, and carried out the safety performance inspection.Referring to the dimensions of the hub motor stator windings, finished the design of flameproof joints; completed flameproof enclosure stress analysis and size calculation, also build the CAD model of flameproof enclosure of the explosion-proof hub motor. Established the CAE finite element model of the flameproof enclosure by ANSYS Workbench, completed the grid division by checking material definition and boundary conditions on the model. Realized the stress computation of the finite element model, obtained and analyzed stress images under pressurized conditions of 1.5 Mpa.Tested the explosion-proof performance of the explosion-proof hub motor prototype; checked the flameproof joints of the prototype; passed the pressure test and explosion non-transmission test, proved the correctness of the explosion-proof design.Designed and carried out suitable power supply for the explosion-proof hub motor; tested the power supply on the basis of latest coal-mine power standard, the tests included short circuit test, overcurrent test, overpressure test, temperature test, and accuracy test; the results are qualified, proved the correctness of the power supply design.