| The propelling screw is an important component of the coal powder centrifugal dryer,which is used to feed the coal powder into the centrifugal dryer.Due to the use of coal powder as the propulsion material,the spiral blades need to be wear-resistant,so small ceramic tiles need to be installed on the working surface of the spiral blades.The fixing method between the small ceramic tile and the spiral blade is bolted connection,and it is necessary to drill holes on the spiral blade to facilitate the fixing of the small ceramic tile.Due to the unique structure and large volume of the propulsion spiral,with different sizes: the blade thickness is 10 mm,the blade spacing is about 140 mm,the maximum length is nearly 2.4 meters,the diameter is 1.6 meters,and the weight is about 2.7 tons.Existing drilling machines such as bench drills and rocker drills cannot meet the requirements for drilling on the spiral blades.Therefore,the current drilling method uses manual electric drills for drilling.However,this method has many problems,such as insufficient drilling positioning accuracy Labor costs are relatively high,processing efficiency is low,and safety issues are also prone to occur.This paper focuses on the detailed structure and size of the propelling screw for special workpieces,and designs a propelling screw automatic positioning drilling machine.It has achieved the research and production of this type of workpiece drilling machine from scratch,solving the problems of manual drilling.The specific research content is as follows:Firstly,identify the difficulties in the design of this machine: the volume and weight of the propulsion screw are large,making it difficult to move;The spacing between the blades is small,and a drilling machine head needs to be designed within140 millimeters;The drilling includes two rows,and the positioning of the holes requires precision and fast positioning speed.It is necessary to study an automatic positioning system.Secondly,the whole equipment is preliminarily designed according to the design steps and principles of the mechanical equipment,and the whole equipment is divided by the functional analysis method,and each part with different functions is named: the head part of the drilling machine,the suspension support part,the lifting part,the base and the main shaft support part,and the drag chain part.Thirdly,the part structure of each parton subsystem is designed in detail through CAD software,and the drawings available for processing are drawn.At the same time,the driving mode and driving elements of the whole equipment are determined through calculation and analysis.The overall structure of the drilling machine is constructed in Solid Works and CATIA according to the engineering drawings,so that the entire design is integrated.Fourthly,the reliability of the main load-bearing structure of this equipment was verified through theoretical calculations and the use of finite element analysis software.By comparing the analysis results,the design scheme of the main load-bearing structure was optimized.Introduce numerical simulation technology and use ANSYS Workbench for modal analysis of the overall equipment to prevent resonance from affecting machining accuracy.Finally,the electrical control system of the automatic positioning drilling machine was designed,and the entire equipment was processed,assembled,and debugged for experiments.The actual measurement of the machining efficiency and the true distance between the hole center and the edge of the spiral blade are obtained through the drilling experiment,which verifies that the drilling meets the technical requirements.By calculating the equipment capability index Cmk,it has been proven that the propelling spiral automatic positioning drilling machine meets the capability requirements for drilling processing. |
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