The large number of research achievements have been made in the machining technology of spiral bevel gears at home and abroad. Foreign countries have developed from the original pure mechanical manual control spiral bevel gear cutting to the current “zero mechanical transmission” full CNC multi axis linkage cutting. China has also developed from the initial imitation of spiral bevel gear cutting machine tools to the improvement and perfection of CNC cutting machine tools and cutting technology. These research results have greatly improved the cutting efficiency, tooth surface accuracy and reduced the tooth profile deviation, and realized the dry cutting characterized by environmental protection and the cutting of large-size spiral bevel gears with a large end indexing circle radius of more than 2m. However, the research on spiral bevel gear machining technology at home and abroad is based on Gleason gear cutting system, using engineering approximate gear cutting method. Using this technology to carry out tooth blank design, cutting motion control, tool design, machine tool adjustment and tooth shape correction is extremely complex, CNC system and bevel gear processing equipment are extremely expensive, and the core and key technology of spiral bevel gear cutting has been blocked by foreign countries, which seriously restricts the progress of spiral bevel gear processing technology in China.
(1) A new method of three-axis linkage milling of spiral bevel gear based on the generation principle of spherical involute tooth surface is proposed, which breaks through the existing Gleason gear cutting system. According to the principle that the tooth surface of spiral bevel gear can be generated by pure rolling of the arc generating line on the base cone, the tooth surface generating line is used as the cutting edge, and the inverse motion of the tooth surface generating motion is used as the cutting motion. The tooth surface of spiral bevel gear without principle error can be cut only by three-axis linkage. Because the processed bevel gear tooth surface does not have envelope polygon, it is very conducive to improve the quality of the processed bevel gear tooth surface.
(2) The shape of the cutting edge of the milling tool is designed as circular arc, and the convex and concave tooth surfaces of the spiral bevel gear are processed by the inner edge milling cutter and the outer edge milling cutter respectively. The structure of the cutter is greatly simplified, and the manufacturing and grinding are simple and convenient, without the need for a special tool grinding machine.
(3) Based on the in-depth study of the generation principle of spherical involute tooth surface and the new method of three-axis linkage milling, the tooth cutting motion is further simplified, and a new method for machining the tooth surface of spherical involute spiral bevel gear with only two axis linkage is proposed. This method does not need special gear cutting tools and CNC system, and greatly reduces the processing cost.
In view of the above problems, this paper breaks through the existing Gleason gear cutting system of spiral bevel gear processing, studies the new method of spiral bevel gear cutting based on the generation principle of spherical involute tooth surface, and studies two new methods of gear milling with relatively simple cutting motion. One is to take the arc generating line of the tooth surface as the cutting edge, and the tooth surface of spiral bevel gear without principle error can be processed by means of three-axis linkage. The other is based on the research of the former processing method, using several discrete points to approximately replace the arc generating line of spiral bevel gear, and the milling of spiral bevel gear tooth surface can be realized through a simpler two-axis linkage mode.