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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 a straight line instead of an involute (planar for the tooth surface) , equal to the indexing circle radius is usually infinite cylindrical gear.
2. The main features:
(1) Since the tooth profile of the rack is direct, each point on the tooth profile has the same pressure position and is add up to the inclination angle of the tooth profile. This angle is called the tooth position and the typical value is 20°.
(2) The same pitch and modulus are provided on the direct lines parallel to the top line.
(3) A series parallel to the top type of the tooth and having a tooth thickness equal to the width of the tooth groove is named a dividing line (middle line), which is a reference collection for calculating how big is the rack.
3. The main parameters:
Groove width, high tooth tip, high root elevation, tooth height, tooth thickness, root radius, etc.
4. The decision of parameters:
(1) Whether the equipment 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 has gone out of tolerance.
(2) If 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, runout, and common normal line of the rack are skilled.
5. Processing methods:
Gear rack and pinion machining technique:
(1) hobbing
(2) gear shaping
(3) shaving
(4) grinding teeth
(5) molars