The Design Of Machining Device For The End Blade Pin Hole Of Dteam Turbine Rotor

The end blades located in the steam turbine rotor impeller at all levels are connected in a locking structure of the cone pin. Because the minimum distance between every two stages of the impeller can reach 75 mm, ordinary drilling is difficult to meet the requirements of hole making. In order to improve the processing efficiency, a new type of drilling device is designed for the present situation of the company. The new drilling device is composed of four parts, including clamping, feeding, transmission and balance devices. The clamping part of the drilling device make the device clip fastened dexterously in a short time. Through the manual control of the handle, the movement of XYZ directions can be realized. The balance device can reduce the labor intensity of workers and improve working efficiency.The new drilling device is fixed on the steam turbine rotor and the hole drilling of the last stage blade of pin hole is completed with a processing method similar to “ants gnawing a bone”. Positioning and clamping device play the role of fixing the whole device. The positioning mechanism adopts the positioning mode of “two pins on one side ", with a round pin and a cutting edge pin. some fast calipers and connectors are used in clamping mechanisms. The feeding device is designed to realize the movements of the drilling device in XYZ directions manually controlled. In order to realize the spindle rotation of the drilling bit, the transmission device is driven by transfer motion of belt transmission with 3:1 reduction to drive power. The function of the balancing device is to make the drilling device to be in a state of weightlessness and ensure that the drilling process can be carried out smoothly.Finite element analysis is used to analyze the strength of some components of drilling device, including the connection frame of Y direction of the feeding device, the spindle, and the bevel gear, the acme thread lead screw of Z direction, and the connecting frame in the clamping mechanism, etc. In addition, some optimization in the design are also carried out.