Gear rack is a special gear whose teeth are distributed about 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 account of the rack is definitely a straight line rather than an involute (planar for the tooth surface) , equivalent to the indexing circle radius is usually infinite cylindrical gear.
2. The main features:
(1) Since the tooth profile of the rack is straight, each point in 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 standard value is 20°.
(2) The same pitch and modulus are provided on the straight lines Taper Pulleys 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 range for calculating the size of the rack.
3. The main parameters:
Groove width, high tooth tip, 
high root height, tooth elevation, 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 mistake is out of tolerance.
(2) If the 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 complete tooth depth, runout, and common normal line of the rack are experienced.
5. Processing methods:
Gear rack and pinion machining method:
(1) hobbing
(2) gear shaping
(3) shaving
(4) grinding teeth
(5) molars
