Gear rack is a particular gear whose teeth are distributed in the strip.
1. The basic concept:
The rack can be 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 definitely a straight line instead of an involute (planar for the tooth surface) , equal 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 gets the same pressure angle and is add up to the inclination angle of the tooth profile. This angle is named the 
tooth position and the standard value is 20°.
(2) The same pitch and modulus are given on the right lines parallel to the very best line.
(3) A collection parallel to the top line of the tooth and having a tooth thickness add up to the width of the tooth groove is called a dividing line (middle line), which is a reference collection for calculating how big is the rack.
3. The main parameters:
Groove width, high tooth tip, high root elevation, tooth height, tooth thickness, root radius, etc.
4. The choice of parameters:
(1) Whether the equipment is beating, the full tooth depth, the common normal series, the tooth direction is qualified, the tooth pitch is poor, and the circumferential section error has gone out of tolerance.
(2) If the installation distance after the gears and racks are installed is suitable.
(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 Rotary Air Compressor shaping
(3) shaving
(4) grinding teeth
(5) molars
