In addition to issues with the gearbox's own oil seals, the design and assembly of gearbox components by robot manufacturers can also have an impact. The sealing of the gearbox involves not only oil seals but also O-rings.
O-rings are standard components commonly used for product sealing, and there are corresponding national standards for reference. In robot gearboxes, most manufacturers provide O-rings and O-ring grooves. In some cases, manufacturers do not provide O-rings, and there are no O-ring grooves on the gearbox, so it needs to be designed on the mounting flange. However, due to capillary action, the base oil can still penetrate.
2. Assembly design and assembly process
Why do many domestic manufacturers wonder why they experience more frequent failures compared to the four major families when using the same HD or Timken gearbox? This may be due to immature assembly processes. The structure can be easily dismantled and observed, but assembly design and processes are not visible to the robot, even in the drawings. Mature robot manufacturers have professional process engineers who specialize in robot assembly, including gearbox assembly.
3. Servo control
Servo control has a significant impact on the gearbox. This includes the entire system of the motor, driver, and controller. If the servo performance is poor or not properly tuned, the motor is prone to vibration at different speeds or loads. Even with poor mechanical design, resonance can frequently occur. In terms of servo selection, it is an aspect that domestic robots do not pay much attention to. Domestic robots emphasize cost-effectiveness, but in practical operations, many tend to prioritize price rather than performance.
4. Excessive usage time
Can robots work tirelessly? It is actually a misconception. Firstly, robots need rest. It is generally recommended for robots to work for 12 hours and rest for 1 hour. Of course, this recommendation is for relatively demanding working environments. If the robot is operating comfortably, it can be run for 24 hours. Secondly, robots require maintenance. Robots are precision equipment and need regular maintenance to reduce wear and tear and extend their lifespan, just like cars.
5. Overloading and impact
This situation is quite common in China. Each robot model has specified load and inertia design values. It is important to consider both the load and inertia, but many customers only focus on the load and overlook the inertia. Therefore, sometimes the load may not be exceeded, but the inertia can be significantly exceeded, resulting in various issues with the robot.
Another issue is impact. There are two types: collisions and sudden stops, including abrupt stops or sudden power cuts. Impact is relatively tolerable for RV gearboxes, as they have better rigidity. However, the number of impacts should not be excessive. But for harmonic gearboxes, they are very sensitive to impact. Collisions generally occur during the debugging process or as accidents during production. These are generally unexpected occurrences, not subjective, but sudden stops often result from subjective and non-standard operations.