Friends in the machining industry are certainly no strangers to gears. Let us talk about its classification and application today.
Involute cylindrical gears are the most used gears. There are two types of knives for machining involute cylindrical gears: forming gear cutters, such as disk gear milling cutters and finger gear milling cutters, and generating gear cutters, such as gear hobs, gear shaper cutters, and gear shaving cutters.
1. Forming gear milling cutter
(1) Disc gear milling cutter
In the horizontal milling machine, the dividing head is used to divide the teeth, the disc gear milling cutter is used for rotating movement, and the worktable is used for feed movement to process straight or helical cylindrical gears. The productivity and machining accuracy are relatively low, and it is suitable for cylindrical gears that do not require high machining requirements in single-piece production or repair work.
1. Geometric parameters of disc gear milling cutter
The blade shape of the disc gear milling cutter is designed according to the groove shape and size of the machined gear. The disc gear milling cutter is a relief tooth forming milling cutter, the rake angle γf=0°, so that the blade shape is the same as the tooth groove shape, in order to reduce the tooth profile machining error.
In order to facilitate cutting, the tooth tip clearance angle αf and the tooth flank clearance angle αn are also made by cutting. K is the removal amount of the tooth tip clearance angle αf.
2. Selection of disc gear milling cutter
When machining gears with a disk gear milling cutter, the gear modulus and pressure angle are the same, but the number of teeth is different, and the shape of the cogging is also different. According to the principle of involute formation, the smaller the number of teeth, the smaller the base circle, and the more severe the involute bends. Therefore, when machining gears with different numbers of teeth, milling cutters with different tooth profiles should be used, which will make the number of milling cutters particularly large. In order to reduce the number of disc gear milling cutters in production, a milling cutter is commonly used to process gears with the same modulus and pressure angle, but the number of teeth specifies the processing range.
(2) Finger gear milling cutter
When the machining gear modulus is greater than 10mm, the indexing head is used to divide the teeth on the vertical milling machine, the finger gear milling cutter rotates, and the worktable performs feed movement to perform tooth milling. This processing method is only suitable for single-piece production and repair work.
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