rackIt is also divided into spur racks and helical racks, which are used in pairs with spur gears and helical spur gears respectively; the tooth profile of the rack is a straight line rather than an involute (for the tooth surface, it is a plane), which is quite The main features of the gear rack are that the indexing circle radius is infinite.
1. Since the tooth profile of the rack is a straight line, each point on the tooth profile has the same pressure angle, which is equal to the inclination angle of the tooth profile. This angle is called the tooth profile angle, and the standard value is 20°.
2. Any straight line parallel to the tooth top line has the same tooth pitch and modulus.
3. The straight line parallel to the tooth top line and the tooth thickness equal to the slot width is called the index line (center line), which is the reference line for calculating the rack size.The main parameters of the rack: tooth slot width, tooth tip height, tooth root height, tooth height, tooth thickness, tooth root circle radius, etc.