Research On Processing Method Of Large Cycloidal Bevel Gear

Spiral bevel gears are widely used in various mechanical equipment for the transmission of intersecting and staggering shafts,such as automobile,ship,aerospace,engineering machinery,mining machinery,drilling platform and other different working conditions.According to the pitch bevel tooth line,the spiral bevel gears can be divided into arc bevel tooth gear of arc tooth system and cycloid tooth bevel gear of extended epicycloid tooth system.As a result of the later one form having compact structure and higher load-carrying capacity in transmission,thus it is mainly used in large-scale mechanical equipment.And its manufacture accuracy and process quality all directly affect use efficiency,failure rate,service life and so on.Thus it is necessary to carry out the research about the process method of cycloidal tooth bevel gears,and main research results are as follows:(1)Based on the process principle of Klingelnberg cycloidal tooth bevel gear,the method of processing cycloidal tooth bevel gear with split cutter-head has been studied.The method of controlling the contact area of tooth surface by split cutter-head was researched out,and the conjugate transmission of point contact of gear pair was realized.And also the theoretical foundation for the processing of cycloidal tooth bevel gears on GCMT2500 CNC machine tools has been established.(2)Based on the characteristics of GCMT2500 CNC machine tools,a kind of the universal milling cutter-head for processing cycloidal tooth bevel gears was designed,which could simplify the structure of cutter head and reduce the time of tool being replaced.The suitable blade is selected to cut the tooth surface by the factors such as the material of pinion and the size of pressure angle.According to the structure style of milling cutter-head,then the process route of cycloidal tooth bevel gears is drawn up,so the milling process of cycloidal tooth bevel gears could be divided into three phases,such as roughing,semi-finishing and finishing.In the process of finishing,three kinds of cutting methods were studied out when the tooth surface being cut,and vertical-cutting method,cross-cutting method and oblique-cutting method were included.Then accuracy detections of obtained tooth surface were conducted by these three cutting methods.Finally it could be concluded that the accuracy of obtained tooth surface by oblique-cutting was the highest,and with the result that the oblique-cutting was finally determined in the process of finishing.(3)In the process of finishing,the surface roughness of gear was measured by hand-held roughness measuring instrument.Using the single factor control variable method,the cutting experiment towards the tooth surface was carried out,selected the rounded corner radius of the tip of cutter blade,feed rate and cutting depth as variables,and a series of data were obtained,which were handled by MATLAB software,and got the chart of variation rule between the surface roughness of tooth surface and the each variable.According to the result of cutting experiments,when the rounded corner radius of the tip of cutter blade R=0.8mm?feed rate f=0.1mm/r and cutting depth t=0.2mm,Ra=1.312 ?m.The tooth surface accuracy of gear is the highest.Based on the process principle of cycloidal tooth bevel gear,a new process method has been proposed in this paper.Thus the processing of cycloidal tooth bevel gears can be realized,which greatly reduces the manufacture cost and improves the manufacture efficiency.