Realization of additional rotation and other motions of helical cylindrical gears

At present, the additional rotation in the slotting process of spiral gear is widely realized by the spiral guide rail. As shown in the figure, the fixed guide rail is fixed in the indexing worm gear hole, and the sliding guide rail is connected to the cutter shaft of the gear shaper, and its helix direction is consistent with the helix direction of the gear shaper. When the indexing worm gear rotates, the fixed guide rail drives the sliding guide rail, cutter shaft and gear shaper cutter to rotate together to complete the shaping movement. When the cutter shaft drives the gear shaper cutter and sliding guide rail to reciprocate up and down with respect to the indexing worm gear and fixed guide rail, additional rotation is generated under the forced guidance of the spiral guide rail surface, forming the spiral cutting movement, and the working stroke is opposite to the spiral direction of the return stroke. The lead of spiral guide rail shall be equal to the lead of gear shaper and workpiece. When machining workpieces with different helix angles, it is necessary to replace gear shaper and helix guide rail.

In the traditional gear shaping process, the transmission and processing of energy and motion information between the head and end pieces connected with the internal and external transmission chain, as well as the control of the position and speed of the actuator are all made of “hard” transmission elements such as gears, worm gears, racks and other mechanical transmission elements. The setting of transmission ratio is also realized by changing the transposition mechanism in the gearbox, such as the circular feed mechanism is adjusted by the change gear rack, The radial feed is controlled by the feed cam or feed screw, and adjusted by the change gear. The gear change gear is used to adjust the hobbing and gear cutting movement on the machine tool, so that the tool movement is controlled by the cam. In the processing of spiral gear, it is necessary to design and manufacture special spiral guide rail and suitable spiral gear shaper.

The accuracy of these transmission parts will directly affect the accuracy of the transmission chain, and then affect the accuracy of the workpiece to be processed. In the transmission chain, due to the influence of the processing error of the adopted transmission parts themselves, the existence of the gap in the transmission chain, the existence of the installation error, wear, thermal deformation, etc., will have a great impact on the accuracy of the relative motion between the slotting cutter and the workpiece, which will directly affect the accuracy of the gear cutting and forming of the workpiece, At the same time, because of the weakness that the parameters of the mechanical transmission chain can not be adjusted in the process of cutting teeth, the types of the profile curve forming of the workpiece gear are limited. In addition, the precision of the spiral guide rail is very high, and the spiral angle of the gear must be the same as that of the spiral guide rail of the gear shaper, which will limit the design parameters of the spiral gear.

Starting from the forming principle of the profile curved surface of the helical gear, the characteristics of the helical gear transmission are analyzed, and the forming principle and the forming movement of the helical gear are deeply studied. Then it introduces the common processing methods of spiral gear – gear hobbing and gear shaping, and makes a detailed comparison of the advantages and disadvantages of these two processing methods. Finally, according to the principle and motion analysis of the spiral gear slotting machining, the paper studies the machining principle, transmission schematic diagram, motion analysis and the realization of additional rotation.