Introduction
A gear or rack gear cutter. Insertion cutters are used to machine internal and external meshed spur and helical gears by the generative method. The features of the pinion cutter are that it can be processed with shoulder gears, multiple gears, and no-slotted herringbone gears. The special shape cutter can also process a variety of other contoured workpieces such as cams and internal splines.
classification
The cut-tooth cutters are divided into four types: disc shape, bowl shape, barrel shape, and taper shank. The disc-shaped cleaver is mainly used for machining internal and external meshing spur, helical and herringbone gears. The bowl shaper cutter mainly processes spur gears with shoulders and multiple internal and external meshing gears. The difference between it and the disk shaper cutter is that the nuts used for clamping can be accommodated in the cutter body of the gear cutter. It does not interfere with processing. The cylindrical gear cutter is used for machining internal gears and external gears with small module numbers, and is screwed on the main shaft of the gear shifter by the thread of the inner hole. Taper shank cutter is mainly used for machining internal meshing spur and helical gears.
operating
In order to produce the tooth profile of the processed gear after the back angle and regrind, the shape of the distorted gear is made in each section perpendicular to the axis of the pinion cutter, and the displacement coefficient X0 gradually decreases from the front end face to the rear end face, and Change from positive to negative. The shaper cutter is subject to some restrictions in use. 1 The limitation of the gear cutting: When inserting the involute tooth shape of the cut gear root into the incisor gear tooth during the cutting process, it is called undercut, and the less the number of teeth of the gear being processed, the greater the possibility of undercutting. . 2 Limits of gear cutting: Top cutting refers to the phenomenon that the top of the gear being cut into the root of the pinion cutter is cut off the top of the tooth. The smaller the number of teeth and the coefficient of displacement of the gear, the easier it is to cut. 3 The limitation of the gear transition curve interference: When the cutting tool is in the cutting tooth, it cannot cut out the involute tooth profile on the whole tooth surface, and it is a transition curve at the gear root. The smaller the number of teeth of the pinion cutter and the larger the tooth profile displacement coefficient, the longer the transition curve. If the tip of the mating gear is in contact with the transition curve, interference will occur. 4 For gear shaping cutters that process internal gears, consideration should also be given to the fact that the insert cutter does not have the restriction of top cutting during radial cut-in.
The accuracy of the standard pinion cutters is divided into 3 types according to international standards: AA grade, A grade and B grade. Under the normal conditions, they are used to process gears with precision grades 6, 7 and 8 respectively. In order to process gears that need to be shaved or geared, the shaved or pre-grinding cutters must be used separately to leave a certain allowance for the gear tooth surfaces. Therefore, the tooth shape of these gear cutters needs to be specially designed.
When machining external and internal meshing helical gears and herringbone gears, it is necessary to use helical gears. When machining an externally meshed helical gear, it is necessary to use two helical gear shaping cutters, whose direction of rotation is opposite to that of the machined gear; when machining a pair of internally geared helical gears, the cutters that process the internal gear helical gears are The rotation of the gears is the same. Helical cutting tools are inclined because of the cutting teeth. The rake angles of the blades on both sides are very different. One side is a positive rake angle and the other is a negative rake angle. In order to improve the working conditions of the plunging tool, special sharpening is required. .
The working principle of the comb cutter is similar to that of the cutter cutter. It can be considered as a special case when the number of teeth of the cutter cutter is infinite, and there are two kinds of straight teeth and helical teeth. The comb cutter has a simple shape and is easy to manufacture. It is used for machining external meshing straight gears, helical gears and herringbone gears, and is particularly suitable for machining larger module gears.
Generally, the cutting tools are made of high-speed steel, and the carbide cutting tools are still in the experimental research stage.