Gear rack is a particular gear whose teeth are distributed about the strip.
1. The basic concept:
The rack is also split into a spur gear rack and a helical gear rack, which are paired with a spur gear and a helical gear, respectively; the tooth profile of the rack is certainly a straight line instead of an involute (planar for the tooth surface) , equivalent to the indexing circle radius is normally infinite cylindrical gear.
2. The main features:
(1) Since the tooth profile of the rack is straight, each point about the tooth profile has the same pressure position and is equal to the inclination position of the tooth 
profile. This angle is called the tooth angle and the typical value is 20°.
(2) The same pitch and modulus are given on any of the right lines parallel to the top line.
(3) A range parallel to the top type of the tooth and having a tooth thickness add up to the width of the tooth groove is named a dividing line (middle line), which really is a reference range for calculating how big is the rack.
3. The main parameters:
Groove width, high tooth suggestion, high root height, tooth height, tooth thickness, root radius, etc.
4. The choice of parameters:
(1) Whether the gear is beating, the full tooth depth, the normal normal line, the tooth direction is qualified, the tooth pitch is poor, and the circumferential section mistake is out of tolerance.
(2) Whether the Planetary Gear box installation distance after the gears and racks are installed is appropriate.
(3) The rack and gear meshing clearance should be 0.25* modulus.
(4) Whether the full tooth depth, runout, and common normal type of the rack are qualified.
5. Processing methods:
Gear rack and pinion machining technique:
(1) hobbing
(2) gear shaping
(3) shaving
(4) grinding teeth
(5) molars
