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 a straight line instead of an involute (planar for the tooth surface) , equivalent to the indexing circle radius is infinite cylindrical gear.
2. The main features:
(1) Since the tooth profile of the rack is direct, each point in 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 typical value is 20°.
(2) The same pitch and modulus are given on any of the right lines parallel to the very best line.
(3) A line parallel to the very best type 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 how big is the rack.
3. The main parameters:
Groove width, high tooth tip, high root height, tooth elevation, tooth thickness, root radius, etc.
4. The decision of parameters:
(1) Whether the equipment is beating, the entire tooth depth, the normal normal series, the tooth direction is qualified, the tooth pitch is poor, and the circumferential section mistake has gone out of tolerance.
(2) Whether 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 full tooth depth, runout, and common normal type of the rack are competent.
5. Processing methods:
Gear rack and pinion machining technique:
(1) hobbing
(2) gear shaping
(3) shaving
(4) grinding teeth
(5) molars