The reversing ability of a planetary gearbox is closely related to its design and application scenarios. Conventional planetary gearboxes are generally not self-locking and can theoretically be operated in reverse. This means that when the output shaft is driven by an external force, the input shaft follows the rotation. This property is the result of the transmission principle of the planetary gearbox: the meshing of the sun gear, planetary gear and inner ring enables bidirectional power transmission. Reversing is easier, especially when there is little or no load. For example, the high reversing ability of the planetary gearbox (for example, the reversing efficiency of the 3K planetary gearbox can reach 90%) when operating robotic joints ensures that the joint responds quickly during dynamic movements and avoids the delay caused by self-locking.

In practice, however, the following limitations must be observed:

✅ Load and transmission efficiency: If the load exceeds the reverse torque threshold of the transmission, reversing may not be possible. For example, the reverse torque of some planetary gearboxes can reach 1.5 times the rated torque. Exceeding this range will cause slippage or damage to the transmission.

✅ Self-locking design: Some special designs (such as self-locking planetary gears) achieve reverse self-locking by using additional friction discs or optimized tooth engagement angles to prevent accidental slippage of the load. This type of design is often used in lifting equipment or precision positioning systems. For example, the end effector of an industrial robot must maintain its position even when the power is cut off.

✅ Application scenario requirements: In situations where reverse movement must be prevented (such as in logistics conveyors), additional brakes or freewheel clutches are usually required. In the case of the Siemens Forum, for example, the car skidded because the gearbox was in reverse. The problem was solved by optimizing the inverter parameters and installing mechanical locks.

In summary, the reverse rotation capability of the planetary gearbox depends on the specific model and operating conditions. Conventional models support reverse, but attention must be paid to load regulation and protective measures. Self-locking models limit reverse through their design. In the actual selection, due consideration must be given to torque requirements, accuracy requirements, and safety regulations.