Servo motors are widely used in automation equipment, but abnormal noise during operation not only affects the working environment, but may also indicate potential equipment failures. This article will systematically analyze the causes of servo motor noise and provide detailed solutions to help engineers quickly diagnose and eliminate various noise problems to ensure stable operation of the equipment.
Mechanical structure noise treatment
Mechanical structure problems are the main source of servo motor noise. First, check whether the coupling is well aligned. The radial and axial deviations should be controlled within 0.05mm. Bearing wear is another common cause. When you hear a regular “clucking” sound, you should replace the bearing in time and ensure that the appropriate brand of grease is used. For gear transmission systems, check the wear of the tooth surface and grind or replace it if necessary. Loose motor mounting bolts will produce obvious vibration noise. It is recommended to use a torque wrench to tighten it according to the standard torque. The resonance of the base will also amplify the noise, which can be improved by adding damping materials or changing the installation method.
Electrical system noise optimization
Electrical noise usually manifests as high-frequency howling. First, check the PWM carrier frequency setting. Properly increasing the frequency can reduce audible noise, but the switching loss needs to be weighed. Improper cable routing will introduce electromagnetic interference. The power line should be separated from the signal line. If necessary, use shielded cable and ensure good grounding. Unbalanced motor phase current will produce specific frequency noise, which can be improved by re-tuning the drive parameters. Abnormal noise will also be caused when the encoder signal is disturbed. Check whether the encoder connector is in good contact and add a magnetic ring filter if necessary. Unstable power supply voltage will also cause noise. It is recommended to install a voltage stabilizer or filter at the input end of the power grid.
Control parameter adjustment tips
Inappropriate control parameters are an important cause of noise. Too high proportional gain of the speed loop will produce high-frequency oscillation, which is manifested as a harsh howling sound. It should be gradually reduced until the noise disappears. Improper setting of the integral time will cause low-frequency jitter. When adjusting, both response speed and stability should be taken into account. For mechanical systems with high rigidity, a notch filter can be enabled to eliminate specific frequency resonance. Modern drives usually provide vibration suppression functions, which automatically identify mechanical resonance points and suppress them. Noise that occurs during acceleration and deceleration can be made smoother by optimizing S-curve parameters. If the load inertia ratio exceeds the recommended range, it will also cause noise, and the motor specifications need to be re-matched or the mechanical transmission ratio needs to be adjusted.
Daily maintenance and monitoring
Establishing a regular maintenance plan can effectively prevent noise problems. Check the tightness of mechanical connection parts every month, clean the motor cooling duct every quarter, and replace the bearing grease every year. Use a vibration analyzer to regularly monitor the motor vibration spectrum to detect potential problems early. Infrared thermal imagers can help find hot spots, which are often accompanied by abnormal noise. Record the noise characteristics during normal operation for subsequent comparative analysis. Keep the motor working environment clean to avoid dust accumulation that affects heat dissipation and mechanical movement. Establish a motor operation log to record the trend of parameters such as current and temperature.
Solutions for special application scenarios
In applications that require ultra-quiet, you can choose a low-noise dedicated motor model. Such products usually use special electromagnetic design and vibration reduction structure. Direct-drive motors can be considered to eliminate transmission noise in medical equipment and other occasions. For extreme environments, choosing a motor with a higher protection level can prevent foreign matter from invading and generating noise. In high-precision applications, it is recommended to use a magnetic encoder instead of an optical encoder to reduce reading noise caused by dust. When multiple motors work together, reasonable planning of motion timing can avoid resonance superposition. In installation locations with limited space, pay attention to heat dissipation when wrapping the motor with sound insulation materials.
Solving the servo motor noise problem requires systematic analysis and processing. Most noise problems can be effectively controlled through mechanical adjustment, electrical optimization, parameter setting and other measures. Regular maintenance and condition monitoring can prevent noise generation and extend the service life of equipment. With the advancement of servo technology, the new generation of intelligent drives have automatic noise identification and suppression functions, providing engineers with more convenient solutions. Understanding the principles and application scenarios of these treatment methods will help you quickly locate and solve various servo motor noise problems.