Gear rack is a special 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 usually a straight line rather than an involute (planar for the tooth surface) , equivalent to the indexing circle radius is definitely infinite cylindrical gear.
2. The main features:
(1) Since the tooth profile of the rack is straight, each point on the tooth profile gets the same pressure angle and is equal to the inclination angle of the tooth profile. This angle is called the tooth angle and the standard value is 20°.
(2) The same pitch and modulus are given on any of the direct lines parallel to the very best line.
(3) A collection parallel to the top type of the tooth and having a tooth thickness equal to the width of the tooth groove is called a dividing collection (middle line), which really is a reference collection 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 decision of parameters:
(1) Whether the gear is beating, the entire tooth depth, the normal normal range, the tooth path is Sprocket qualified, the tooth pitch is poor, and the circumferential section error 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 ought to be 0.25* modulus.
(4) Whether the full tooth depth, runout, and common normal type 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