Gear rack is a special gear whose teeth are distributed about the strip.
1. The basic concept:
The rack is also divided into a spur gear rack and a helical gear rack, which are paired with a spur gear and a helical gear, respectively; the tooth account of the rack is certainly a straight line rather than an involute (planar for the tooth surface) , equivalent to the indexing circle radius is infinite cylindrical gear.
2. The main features:
(1) Because the tooth profile of the rack is right, each point in the tooth profile gets the same pressure angle and is add up to the inclination angle of the tooth profile. This angle is called the tooth angle and the typical value is 20°.
(2) The same pitch and modulus are provided on any of the straight lines parallel to the very best line.
(3) A range parallel to the very best line of the tooth and having a tooth thickness add up to the width of the tooth groove is named 
a dividing range (middle line), which really is a reference line for calculating the size of the rack.
3. The main parameters:
Groove width, high tooth suggestion, high root elevation, tooth elevation, tooth thickness, root radius, etc.
4. The choice of parameters:
(1) Whether the gear is beating, the entire tooth depth, the normal normal collection, the tooth path is qualified, the tooth pitch is poor, and the circumferential section mistake is out of tolerance.
(2) If the installation distance after the gears and racks are installed is suitable.
(3) The rack and gear meshing clearance ought to be 0.25* modulus.
(4) Whether the complete tooth depth, runout, and common normal type of the rack are qualified.
5. Processing methods:
Gear rack and pinion machining method:
(1) Scroll Air Compressors hobbing
(2) gear shaping
(3) shaving
(4) grinding teeth
(5) molars
