Rack as the driving component, gear as the driven component.

1. Determine the modulus m based on the load (refer to the "Mechanical Design Handbook" for the value of m).

2. The pitch diameter D of the driven gear is determined as D = m * z (where z is the number of teeth of the gear).

3. The number of teeth on the gear should be considered comprehensively based on the torque and structure of the load. When the torque is high, the number of teeth can be chosen to be larger, resulting in a larger gear diameter. Conversely, the diameter can be made smaller. 4. After determining the pitch diameter D of the gear, the circumference of the pitch circle can be calculated, assumed to be L.

5. L represents the effective length of the rack. Considering the operation and installation of this item, the actual length should generally be greater than L. The specific amount by which it should exceed L can be determined during the structural design phase.