Gear rack is a special gear whose teeth are distributed on the strip.
1. The basic concept:
The rack can be 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 normally a straight line rather than an involute (planar for the tooth surface) , equal to the indexing circle radius is usually infinite cylindrical gear.
2. The main features:
(1) Because the tooth profile of the rack is straight, 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 called the tooth position and the standard value is 20°.
(2) The same pitch and modulus are given on the direct lines parallel to the top line.
(3) A line parallel to the top type 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 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 full tooth depth, the normal normal range, the tooth path 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 suitable.
(3) The rack and gear meshing clearance should be 0.25* modulus.
(4) Whether the full tooth depth, 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