In the rapid development of modern manufacturing, industrial robots have become a key technology indispensable to the industry. Their high efficiency, stability, and versatility make industrial robots widely used in various fields such as automotive manufacturing, electronic assembly, logistics, warehousing, and healthcare. The successful application of industrial robots relies on many important key technologies, one of which is the gearbox.
What is a gearbox?
A reducer is a mechanical device that reduces the speed of the input shaft and transmits it to the output shaft. It reduces the speed of the input shaft and generates corresponding output torque on the output shaft through gear transmission or other mechanisms inside the reducer. The main purpose of a gearbox is to increase output torque and reduce speed while maintaining output power. This technology is crucial for motion control and torque transmission of industrial robots.
Industrial robots require high-precision motion control and stable torque output, which requires the help of reducers. Gearboxes are commonly used in the joint parts or end effectors of industrial robots by reducing the speed of high-speed motors to achieve higher torque output and precise motion control. The reducer can also make the robot smoother and more precise in performing subtle movements, improving the positioning accuracy and repeatability of the robot.
The function of the reducer:
1. Function enhancement: The reducer enables industrial robots to operate under higher load conditions, providing stronger torque output and enhancing the robot's working ability.
2. Motion control: The reducer reduces the motor speed, providing more precise motion control and enabling the robot to complete more complex tasks and actions.
3. Energy conservation and environmental protection: The reducer reduces energy consumption and improves energy utilisation efficiency by lowering the motor speed, thereby achieving energy conservation and environmental protection.
As a key motion transmission device, the gearbox sometimes experiences some malfunctions. Two common problems are gearbox slippage and gearbox abnormal noise.
Gearbox slippage refers to the phenomenon where the output shaft rotation speed of the gearbox does not match the expected speed due to overload, poor lubrication, or gear wear during operation. This can cause the robot to lose control during movement, affecting its stability and work efficiency.
Root cause analysis
A. Firstly, confirm whether it is a slipping phenomenon of the reducer, which can be achieved by rotating or pushing the mechanical structure with external force (provided that the servo motor without a brake is tested after the servo is enabled normally, and the motor with a brake can be tested when the power is turned off and the servo is enabled normally). If there is obvious displacement, it indicates that the internal transmission gear of the reducer is damaged, jumping teeth or the transmission part of the reducer is completely broken;
B. When the harmonic reducer slips, it may be due to internal structural damage, resulting in complete breakage of the flexible wheel, or it may be due to the detachment of the key strip at the connection between the wave generator and the motor.
C. Due to the wear and loss of teeth on the transmission shaft (RV shaft) or gear plate between the motor and the reducer, the RV reducer may experience slipping.
solution
A. Disconnect the connection between the motor and the reducer, test the motor first, and after the motor is normal, it can be determined that the reducer is abnormal and needs to be replaced with a new reducer.
B. When the RV gearbox shaft is worn, it can be replaced with a new motor shaft or replaced with a new gearbox as a whole (it is recommended to replace it as a set).
C. When the harmonic reducer breaks internally, a new reducer needs to be replaced.
Gearbox abnormal noise refers to abnormal noise or vibration generated during the operation of the gearbox. This is usually caused by gear wear, bearing failure, or improper lubrication. Abnormal noise from the gearbox not only affects the stability of the robot but may also accelerate the wear of robot components, leading to more serious malfunctions.
Root cause analysis
A. Direct or indirect friction occurs between the transmission part of the reducer and the mechanical structure.
B. The internal structure of the reducer is abnormal, and the transmission gears have fallen teeth or worn out.
C. The gearbox is damaged, and intermittent jamming occurs.
D. The internal grease of the reducer is lacking and hardened, losing its lubricating function.
E. The motor rotates eccentrically, causing abnormal noise during the transmission of the gearbox.
solution
A. It is possible to run the abnormal shaft slowly and observe whether there is friction between the transmission parts and the mechanical structure throughout the entire stroke. If no friction occurs, it can be preliminarily determined that it is caused by an abnormality in the reducer, and a new reducer can be replaced for testing.
B. When the gearbox drives forward and reverse at the same speed, is there a phenomenon of inconsistent sound in the forward and reverse directions, and is there a significant difference in sound? If there is a large difference, it indicates that the gearbox is abnormal and can be replaced with a new one.
C. When the gearbox is driven, the sound of forward and reverse rotation is consistent, but the sound is loud. It can be tested with a decibel meter. If the sound is greater than 85 decibels, it indicates that there is an internal abnormality in the gearbox, and a new gearbox can be replaced for treatment.
D. If there is intermittent stuttering or abnormal noise during the transmission of the gearbox, it indicates that the gearbox is abnormal and needs to be replaced with a new one.
E. When there is an abnormal noise due to oil leakage or long-term lack of maintenance and grease replacement in the gearbox, it is necessary to first eliminate the waste grease, then replace it with new grease, and run the test. If the abnormal noise is resolved or reduced to below 85 decibels, it indicates that the gearbox is normal. If the abnormal noise still exists, a new gearbox needs to be replaced.
F. Measure whether there is any jumping of the motor shaft during transmission, with an allowable range of about 0.05mm. The outer surface of the motor shaft can be measured with a dial gauge at the smooth edge.
Therefore, regular inspection and maintenance of the gearbox are key to ensuring the normal operation of industrial robots. Regularly replacing lubricating oil and key components to maintain the good working condition of the gearbox is crucial for improving the stability and lifespan of the robot.
As an important component of industrial robots, reducers are crucial for improving the robot's motion control capability and torque output. Understanding the principles and applications of reducers, as well as how to handle common problems with reducers, will help engineers and technicians better operate and maintain industrial robots, ensuring their stable and efficient operation, and contributing to the development of the modern manufacturing industry.