When designing a ZIMM bevel gearbox of the ZK Series, the values at the input and output are calculated. The calculation includes input torque, output torque, output speed and output power. For load spectra, an equivalent torque is calculated. Gearbox selection is then carried out using design torque, design power and thermal limit power.
How is the input torque at shaft D calculated for a ZIMM bevel gearbox of the ZK Series?
The input torque at shaft D is calculated from input power and input speed.
| Calculation | Formula |
| Input torque at shaft D | TD = PD × 9550 / nD |
How are output torque, output speed and output power calculated for a ZIMM bevel gearbox of the ZK Series?
The output torque is calculated from input torque, drive ratio and gearbox efficiency. The output speed results from input speed and drive ratio.
| Calculation | Formula |
| Output torque at shaft A / C | TAC = TD × i × η |
| Output speed | nAC = nD / i |
| Output power | PAC = TAC × nAC / 9550 |
How are design torque, design power and thermal limit power calculated for a ZIMM bevel gearbox of the ZK Series?
For gearbox selection, the calculated values are multiplied by factors. The operating factor, temperature factor, speed factor and duty factor are taken into account.
| Calculation | Formula |
| Design torque at the output | Ta;AC = TAC × fb × ft × fd |
| Design power at the gearbox | Pa = PAC × fb × ft × fd |
| Thermal limit power | Pt = PAC × fd × ft × fe |
Note: A breather is required from 80% Pt!
How is a load spectrum taken into account when designing a ZIMM bevel gearbox of the ZK Series?
In a load spectrum, load cases with output torque, output speed and time share are taken into account. Equivalent values for torque and speed are derived from this.
| Calculation | Formula |
| Equivalent torque for load spectrum | TAC = (Σ(TAC;n^6,6 × nAC;n × tn) / Σ(nAC;n × tn))^(1/6,6) |
| Equivalent torque for load spectrum Mean output speed for load spectrum | nAC = Σ(nAC;n × tn) / Σtn |
