Are there any references for gear design?

Representation of the reduction ratio: The reduction ratio, which is the transmission ratio of a reduction mechanism, is a type of transmission ratio; it represents the ratio of the instantaneous input speed to the output speed in such a mechanism, and is denoted by the symbol “i”. The reduction ratio is generally expressed as a ratio of the input speed to the output speed, with 1 as the denominator and separated by a colon. For example, if the input speed is 1500 r/min and the output speed is 25 r/min, then the reduction ratio is: i=60:1. In general, the reduction ratio indicated for reduction mechanisms is the actual reduction ratio. However, for some special types of reducers such as cycloidal reducers or harmonic reducers, rounding is sometimes used, and the denominator is not included; for example, the actual reduction ratio might be 28.13, but it is usually indicated as 28. Method for calculating the reduction ratio: 1. Definition of the calculation method: Reduction ratio = input speed ÷ output speed. 2. General calculation method: Gear ratio = Applied torque ÷ 9550 ÷ Motor power × Rotational speed at motor power input ÷ Application factor. 3. Calculation method for gear trains: Reduction ratio = Number of teeth on the driven gear ÷ Number of teeth on the driving gear (In the case of multi-stage gear reduction, multiply together the results obtained by dividing the number of teeth on the driven gear of each pair of meshing gears by the number of teeth on the driving gear). 4. Calculation method for the reduction ratio of belts, chains, and friction wheels: Reduction ratio = diameter of the driven wheel ÷ diameter of the driving wheel.