How many gear processing methods do you know?
Next, we will learn together the following three most commonly used gear processing methods, which are gear hobbing, gear shaping and pulling pin processing.
1. Gear hobbing
Hobbing Involute gears are usually manufactured by hobbing, and as the gear rotates, the teeth of the hob cut into the gear to the final depth. During one revolution of the hob, the gear moves forward one tooth, because the intercept of the cutter corresponds exactly to the tooth pitch of the gear, the gear and the hob. In their sequence of motion a pair of worm gears and worms mesh, so the rotational speeds between the gear and the hob must match each other in order to cut the correct tooth profile. The number of teeth on the gear sets the transmission ratio.
Therefore, when manufacturing an 18-tooth gear, the speed of the single-head hob must be 18 times the speed of the gear. The cutting efficiency of profile teeth is very high, so that particularly thick gears can be produced in a short time.
2. Gear shaping
When it is necessary to produce internal gears, it can be processed by shaping or pulling pins. But wait, look back, a hob can be used to produce gears with any number of teeth, which can then be paired with each other. As can be seen from the animation, use the same hob for machining an eighteen-tooth green gear or a nine-foot gear. It is also possible to produce gear red with six teeth, which is not only suitable for roller teeth, but also for shaper gears. Not only hobbing but also shaping are possible.
However, compared with hobbing, it is only done by the up and down reciprocating motion of the cutter. The cutting edges are arranged like the teeth of a gear on the circumference of the tool during wiping. These scale and horn cutters reciprocate axially during cutting, with the cutting edge pushing into the gear blank and removing material during the cutting stroke. During the pick-up and pick-up, the tool backs up slightly to prevent the reciprocating motion of the tool from colliding with the gear blank, so that the rotary motion of the tool and the superimposed bow and arrow tool rolls on the gear blank in a cutting manner. The tool can actually be thought of as a gear with a cutting edge. The cutting tool rolls on the rim of the gear blank perpendicular to the cutting motion, and then the cutting edge wraps around to form an involute tooth profile. Rack-shaped tools can also be used instead of pinion-type tools in gear machining.
Kinematically, the knives and bows form a kind of rack and pinion, using a rack-style straight-edged cutting edge for reimbursement. Rack cutters can be produced more easily and thus are more cost effective, but cannot machine internal gears. Racks are reimbursed mainly for very large gears, and the following is form decontamination machining using form cutting on the cutting tool. It is considered that the shape of the tooth groove of the gear is completely produced by the rotary motion of the optical tool before the gear blank is turned through a tooth saw, and each tooth is individually decontaminated by a knife.
3. Pulling pin processing
Finally, let’s look at the pull pin processing. Pulling a pin is similar to forming or kicking in terms of motion. However, a broach has multiple cutting edges arranged in sequence, each removing material to sequentially form the final shape. If the broach has passed all the way through the bow, it has usually reached its final shape. Therefore, the pull pin has a high cutting efficiency.
The preceding paragraphs describe three methods of gear machining: gear hobbing, gear shaping, and pin pulling. Among them, gear hobbing can produce gears with any number of teeth, but internal gears cannot be produced; gear shaping can be used in the production of internal gears, but the efficiency is not as good as hobbing; pulling pin processing has the advantage of high efficiency, but it needs to use Multiple cutting edges cut in sequence.