Know: "Rack"

Definition: A flat or straight bar with a series of equidistantly distributed teeth.

The racks are also divided into straight racks and helical racks, which are paired with spur gears and helical gears, respectively; the tooth profile of the rack is straight rather than involute (it is flat for tooth surfaces) The equivalent of the circle radius of the indexing cylinder is infinite.

The main features of the rack

(1) Since the tooth profile of the rack 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°.

(2) The same pitch and modulus are on any straight line parallel to the top line.

(3) A straight line that is parallel to the top line and whose tooth thickness is equal to the width of the slot is called a dividing line (middle line). It is a reference line for calculating the size of the rack.

The main parameters of the rack

The width of the slot, the height of the tooth top, the height of the tooth root, the height of the tooth, the thickness of the tooth, and the radius of the tooth root circle.