齒條的計算公式標准直齒圓柱齒輪的幾何尺寸計算公式4內齒輪與齒條圖示爲一內齒圓柱齒輪，內齒輪的輪齒是分布在空心圓柱體的內表面上。

The racks are also divided into spur racks and helical racks, which are paired with spur gears and helical gears respectively; the tooth profile of the rack is straight instead of involute (for the tooth surface, it is flat) , It is equivalent to an infinite cylindrical gear with the index circle radius. Main features of rack (1) Since the rack tooth profile is a straight line, each point on the tooth profile has the same pressure angle and is equal to the inclination angle of the tooth profile. This angle is called the tooth profile angle, and the standard value is 20°. To (2) Any straight line parallel to the addendum line has the same pitch and modulus. To (3) The straight line that is parallel to the tooth top line and whose tooth thickness is equal to the width of the tooth slot is called the index line (midline), which is the reference line for calculating the rack size. To 　　 The main parameters of the rack Tooth width, tooth tip height, tooth root height, tooth height, tooth thickness, tooth root radius, etc.