Worm gear box and worm gear head are gears that mesh with a worm and have a special tooth profile.The cutting of worm gear teeth is generally done with a gear hobbing machine, and there are mainly two methods: gear hobbing and flying knife gear cutting.When manufacturing precision worm gears, finishing processing such as gear shaving, gear honing or gear grinding can be carried out after gear hobbing or gear cutting.
滚齿
The worm gear hob with the same basic parameters as the working worm is used to cut out the tooth shape according to the principle of the generative method.If using the radial feed method to hob gears, the hob and the workpiece will be rolled according to the transmission ratio of Z 2/Z 1 (Z 1 is the number of working worm threads, Z 2 is the number of worm gear teeth), and the two gradually approach until the center The distance is equal to the center distance when the working worm and the worm gear mesh.
When using the tangential feed method for hobbing, in addition to ensuring the rotation of the tool, the machine tool must also have axial feed. At the same time, the worktable of the machine tool must also be increased by the corresponding additional rotation to achieve the generative motion. This requires the use of differential chain.Therefore, the machining accuracy of the tangential feed method is generally inferior to that of the radial feed method, but the quality of the tooth surface is better, and there is no undercutting phenomenon.The accuracy of the hobbing worm gear is generally up to 6-8 (JB162-60).
The hobbing of precision worm gears needs to be carried out on a high-precision indexing worm gear hobbing machine with a high-precision hob. A mechanical or electronic transmission chain error correction device can also be installed on a general-purpose hobbing machine to improve processing accuracy and higher processing. The accuracy can reach level 3.
Flying knife cutting teeth
The flying knife is equivalent to a tooth of a worm gear hob.The flying knife can only use the tangential feed method to cut the teeth. On the hobbing machine, the flying knife can rotate the worm wheel Z 1 tooth, plus the tangential feed of the flying knife and the additional rotation of the worktable, it can also be developed by The method principle cuts out the correct tooth shape, and the accuracy can reach 7 to 8.The flying knife is simple to manufacture, but the productivity of cutting teeth is low, so it is suitable for single-piece production and repair work.
剃齿
The basic parameters of the worm gear shaving cutter are the same as the working worm.Worm gear shaving generally uses a gear hobbing machine. The gear shaving cutter can drive the worm gear to shaving freely. It can also be forced to shaving under the control of the machine tool transmission chain. The quality and accuracy of the tooth surface after shaving are improved.
Honing and grinding teeth
After worm gear hobbing or flying knife gear cutting, in order to improve the quality of the tooth surface and improve the contact between the worm gear and the worm, the gear hobbing machine can be honing or grinding the gear.The honing tool is a honing worm made by casting a mixture of abrasive, plastic and resin on the substrate; when grinding the tooth, a grinding worm made of cast iron is used to grind the worm wheel.