Gear rack is a special 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 account of the rack is a straight line rather than an involute (planar for the tooth surface) , equivalent to the indexing circle radius can be infinite cylindrical gear.
2. The main features:
(1) Because the tooth profile of the rack is direct, each point about the tooth profile has the same pressure angle and is equal to the inclination position of the tooth profile. This angle is named the tooth position and the standard value is 20°.
(2) The same pitch and modulus are provided on any of the straight lines parallel to the top line.
(3) A series parallel to the very best line of the tooth and having a tooth thickness equal to the width of the tooth groove is named a dividing series (middle line), which is a reference line for calculating the size of the rack.
3. The main parameters:
Groove width, high tooth suggestion, high root height, tooth elevation, tooth thickness, root radius, etc.
4. The decision of parameters:
(1) Whether the equipment is beating, the full tooth depth, the normal normal collection, the tooth direction is qualified, the 
tooth pitch is poor, and the circumferential section mistake is out of tolerance.
(2) Whether the installation distance after the gears and racks are installed is appropriate.
(3) The rack and gear meshing clearance ought to be 0.25* modulus.
(4) Whether the complete tooth depth, Scroll Vacuum Pump runout, and common normal line of the rack are certified.
5. Processing methods:
Gear rack and pinion machining technique:
(1) hobbing
(2) gear shaping
(3) shaving
(4) grinding teeth
(5) molars
