The safety factor of the gear motor refers to when selecting the type of gear motor, the use coefficient of the gear motor (generally > 1, namely the capacity of gear motor > motor capacity) is determined based on the factors including service condition and driven machine, so as to ensure that there is a surplus of rated mechanical energy and thermal energy of gear motor. Factors influencing include running time and load (also known as loading condition).
One of the basic requirements of the gear motor safety factor is to make the gear possible to have enough bearing capacity. At present, for the bearing capacity of the tooth surface, root and bonding, although there is a recognized (standard) calculation method, it is probably still difficult to perfectly complete the gear transmission design for the engineering and technical personnel who have little experience in this area, due to the fact that there are so many factors (commonly shown as coefficients or parameters) and some of them are contradictory as well as interacting. In the calculation for the bearing capacity of the gear motor device, it is very important to choose the appropriate safety factor, because the excessive safety factor will increase the outer dimension and weight of the transmission device, finally increasing the manufacturing cost. While if the safety factor is too small, it may lead to unexpected failure and danger. An appropriate safety factor should be at a reasonable manufacturing cost, which enables the device to meet given reliability requirements.
Minimum safety factor for gear contact and bending fatigue strength:
High reliability (failure rate ≤ 1/10000) 1.50 ~ 1.60, 2.00
Relatively high reliability (failure rate ≤ 1/1000) 1.25-1.30, 1.60
General reliability (failure rate ≤ 1/100) 1.00 ~ 1.10, 1.25
Low reliability (failure rate ≤ 1/10) 0.85, 1.00
Key points of selecting the safety factor of the gear motor:
- Expected discreteness of machining accuracy and material quality of all structural elements in the
- Consequences caused by damage and failure of gear. For example, the consequences caused by tooth bending and fracture are generally more serious than those caused by surface fatigue of gear (pitting), especially in situations related to personal safety, such as cranes, elevators, etc.
- Reliability of data related to assembly, installation and use conditions.
- Reliability of the calculation method.