What are the maintenance tips for servo motors?

1. Basic definition of servo motors

Servo motors are the core actuators in servo systems. They accurately adjust the motion state of mechanical parts (such as position, speed, and torque) by receiving control signals to achieve high-precision control. Its core function is to convert the input voltage signal into the angular displacement or angular velocity of the shaft, thereby driving the controlled object.

2. Working principle of servo motors

The working principle of servo motors is based on the motor body, driver, and control circuit. The motor body is the actuator for mechanical motion. The driver is responsible for receiving control signals and driving the motor to rotate. The control circuit generates control signals and monitors the running status of the motor. The servo motor controls the speed and position of the motor by receiving control signals. It is usually equipped with an encoder to provide feedback to ensure that the motor can accurately reproduce the position, speed, and torque commands of the host computer.

3. Structural design features of servo motors

1. Rotor design: Servo motors usually use three-phase synchronous motors with unique rotor designs. There are many patches on the rotor, which are usually permanent magnets (such as neodymium iron boron materials). There are two ways to install the permanent magnet of the rotor: surface mount and embedded. The surface mount has a simple structure, low manufacturing cost, and small moment of inertia; while the embedded type performs better at higher speeds and has higher mechanical strength and stability.

2. High efficiency: Since the rotor has its own magnetic field, the servo motor does not need to generate a magnetic field through induced current like an induction motor during operation, so its operating efficiency is higher. In addition, the efficiency of the servo motor can usually reach more than 95%, and it has high continuous torque and effective torque, which is suitable for high load and high dynamic response application scenarios.

3. High precision and fast response: Thanks to the feedback of the encoder and the precise control algorithm, the servo motor can achieve very high position and speed control accuracy with minimal error. It responds to the control signal very quickly, and can complete acceleration, deceleration and commutation in a short time, with excellent dynamic performance.

4. Low torque pulsation: Even if the permanent magnet patches on the rotor of the servo motor are closely attached, there will still be gaps, which will cause certain pulsation. By optimizing the design, this pulsation can be minimized, thereby improving the stability of the motor and the accuracy of the speed.

‌5. High overload capacity: The servo motor has a high overload capacity in a short period of time, which means a high maximum torque in a wide speed range. For example, some servo motors can support an overload capacity greater than 300% of the rated torque, and the acceleration time is extremely short, such as only 6-10 milliseconds from 0 to 3000 rpm.

4. Maintenance tips for servo motors

‌1. Regular inspection and maintenance: Regular inspection and maintenance of servo motors is an effective means of preventing failures. The inspection content includes the insulation condition of the winding, the connection status of the lead wire, and the reliability of the grounding system. If problems such as reduced insulation performance or poor wiring are found, they should be handled in time.

‌2. Moisture-proof measures: For servo motors that are in a humid environment for a long time, moisture-proof measures should be strengthened. For example, dehumidification equipment should be installed around the motor, moisture-proof materials should be used, etc., to reduce the risk of the motor being damp. At the same time, when the motor is stopped, the moisture and dirt on the surface of the motor should be cleaned in time to keep it dry and clean.

‌3. Improve installation quality‌: The installation quality of the servo motor directly affects its operating stability and safety. During the installation process, the operating procedures should be strictly followed to ensure that the insulation between the motor and the ground is good, the ground wire is firmly connected, and the grounding resistance meets the specified requirements. After the installation is completed, necessary testing and debugging should also be carried out to ensure the normal operation of the motor‌.

‌4. Use high-quality controllers and drivers‌: The quality of the motor controller and driver directly affects the operating stability and life of the servo motor. Choosing high-quality controllers and drivers can reduce the probability of failure and improve the overall performance of the motor‌.

‌5. Parameter adjustment and optimization‌: Carefully adjust the parameter settings of the servo drive according to the actual application scenario and the performance characteristics of the motor. Reasonably set parameters such as acceleration and deceleration time, speed and torque to avoid overload operation of the motor and ensure that it runs within the comfort zone of the design capacity‌.

‌6. Load adjustment and optimization‌: Thoroughly check the mechanical transmission system and adjust the load to a range that the servo motor can easily withstand. Reduce unreasonable load data to ensure that the robot does not feel difficult during operation and always stays in the comfort zone of the design capacity‌.

‌7. Regular maintenance and inspection‌: In order to avoid servo motor brake failure again, maintenance personnel need to establish a regular inspection system. After each maintenance, the working status of the brake components must be checked in detail, including the wear of the brake pads, the performance of the brake coils, etc. Through regular maintenance and inspection, potential problems can be discovered and solved in time to ensure that the robot can operate stably for a long time‌.

Source:https://plaza.rakuten.co.jp/stepperonline/diary/202504220000/

Installation precautions for hollow rotary actuators

 ‌‌1. Introduction to hollow rotary actuators

The hollow rotary actuator is a special rotary actuator with a hollow structure, which is convenient for installing air pipes and wires in the jig. Its working principle is to achieve the rotation effect through the meshing of the gears of the inner and outer rings. The gears on the inner and outer rings mesh with each other, and the rotation force is transmitted to the inner or outer ring through the transmission mechanism. This design is not only compact and comprehensive, but also has the characteristics of high repeatability, high rigidity and high rotation accuracy.

2. Components of hollow rotary actuators

1. Motor: Provides power source, usually a frameless torque motor with high torque output and high motion accuracy.

‌2. Reducer: Reduces the high-speed rotation of the motor and increases the output torque, so that the actuator can provide a large torque at a low speed. Common types of reducers include harmonic reducers and planetary gear reducers.

‌3. Sensor: Including torque sensors and encoders, which are used to monitor the motion state and position of the actuator to ensure precise control.

‌4. Bearings‌: Support and guide the rotational motion, reduce friction and wear, and improve the service life and precision of the actuator.

‌5. Hollow design‌: The hollow rotary actuator is characterized by its hollow structure inside, which can accommodate cables, water pipes or other pipelines that need to pass through, facilitating internal wiring and maintenance.

3. Main functions of hollow rotary actuators

1. Provide degrees of freedom‌: The hollow rotary actuator provides degrees of freedom for the robot, allowing the robot to move in multiple directions. The degree of freedom of a robot refers to the number of independent coordinate axis movements. The higher the degree of freedom, the more complex the tasks that the robot can perform.

‌2. Improve the load-bearing capacity and precision‌: The performance of the hollow rotary actuator directly affects the load-bearing capacity and precision of the robot. The load capacity of the robot and the precision of the end motion depend on the design and performance of the rotary actuator. High-precision rotary actuators can ensure the stability and accuracy of the robot when performing tasks.

‌3. Realize multi-dimensional precise motion control‌: The hollow rotary platform has high precision, stability and flexibility, and can achieve multi-dimensional precise motion control. This enables the robot to perform high-precision operations in various complex environments, such as high-precision welding, assembly, etc. ‌ .

‌4. Improve production efficiency and reduce costs ‌: By using a hollow rotating platform, the robot can rotate 360 ​​degrees without changing direction, which is very useful for robots that require visual monitoring and data collection, such as patrol robots or filming robots. In addition, in the manufacturing industry, the hollow rotating platform can help robots avoid collisions with conveyor belts and maintain effective operation, thereby improving production efficiency and reducing costs ‌.

4. Installation precautions for hollow rotary actuators ‌ 

1. Installation environment requirements ‌: The hollow rotating platform should be installed indoors to avoid direct sunlight and heat radiation. The working environment temperature should be between 0-50 degrees, and the temperature under the origin sensor should be between 0-42 degrees. The working environment humidity should be less than 85%, and flammable and explosive acidic gases and dust, oil stains, splashing water, etc. should be avoided ‌.

‌2. Installation location selection ‌: Choose a suitable location to install the hollow rotating platform to ensure that it will not be subjected to direct vibration and excessive impact. The installation surface of the equipment should be clean and can be wiped clean with anti-rust oil or gasoline, zinc-sodium water.

‌3. Installation and adjustment of the drive motor: Before installation, the motor input shaft, positioning boss and internal connection parts of the equipment should be cleaned, and avoid using tools such as hammers to prevent damage to bearings or gears. After installation, the drive motor needs to be carefully positioned and precision adjusted to ensure smooth and stable operation of the equipment.

‌4. Sealing inspection: Pay special attention to the sealing inside the equipment, especially the sealing of the rotating shaft of the servo hollow rotating platform. Ensure the sealing inside the equipment to prevent environmental pollution.

‌5. Installation of connecting parts: During the installation process, ensure that the concentricity of the motor input shaft and the output shaft of the hollow platform are consistent, and the outer flanges are parallel. When tightening with bolts, the bolts should be rotated diagonally first, and then tightened one by one to ensure the stability and precision of the equipment.

Source:https://plaza.rakuten.co.jp/yixing/diary/202503270000/

Working principle and maintenance method of permanent magnet stepper motor

1.A brief introduction to permanent magnet stepper motor

Permanent magnet stepper motor (PM stepper motor), also known as PM stepper motor, is a motor that uses the interaction between permanent magnet and electromagnetic coil to achieve stepping motion. Its core feature is that permanent magnet steel is used as the rotor material, and the stator is processed into claw-type tooth poles by stamping, usually using radial multi-pole magnetized permanent magnet steel. This design makes permanent magnet stepper motors have the advantages of low cost, simple structure and high reliability.

2.Working principle of permanent magnet stepper motor

The working principle of permanent magnet stepper motor is based on electromagnetic interaction. When the stepper motor driver receives the control pulse and direction signal, the internal logic circuit controls the winding to be energized in a certain sequence. For example, for a two-phase stepper motor, when both phase windings are energized and excited, the motor output shaft will be stationary and locked in position. If the current of one of the phase windings changes, the motor will rotate one step in a given direction. By changing the direction of the winding current in sequence, the motor can achieve continuous step rotation.

3.Performance advantages of permanent magnet stepper motors

1.High precision: The torque and position control accuracy of permanent magnet stepper motors are very high, and the rotation angle can be accurately controlled to achieve high-precision positioning and motion control. This makes it perform well in applications that require high-precision positioning, such as precision machining equipment, automated production lines, etc.

2.High reliability: Since the mechanical structure and control circuit of permanent magnet stepper motors are relatively simple, and there are no wearing parts such as brushes and commutation mechanisms, they have high reliability and stability and can operate stably for a long time. This is very important for equipment that requires long-term stable operation, such as industrial robots, automation equipment, etc.

3.No noise and pollution: Permanent magnet stepper motors do not generate noise or pollutants caused by friction and wear because they have no mechanical contact parts, so they are very suitable for applications with high environmental requirements. This is a significant advantage for equipment that requires a quiet operating environment, such as medical equipment, precision instruments, etc.

4.Controllable speed and acceleration: The speed and acceleration of permanent magnet stepper motors can be precisely controlled by the controller, and have broad application prospects. This is very useful for applications that require precise control of movement speed and acceleration, such as CNC machine tools, automated production lines, etc.

4.Maintenance methods for permanent magnet stepper motors

‌1.Keep the motor clean‌: Regularly remove dust from the surface of the stepper motor, use organic solvents that do not cause corrosion to clean it, ensure that the motor surface is clean, and avoid dust affecting the motor's aesthetics and heat dissipation effect‌.

‌2.Check the bearing wear‌: Regularly check the bearing wear and replace the severely worn bearings in time. Ensure that the bearings have an appropriate amount of lubricating oil to reduce friction and wear‌.

‌3.Check the wiring and screw looseness‌: Regularly check whether the motor wiring is loose, and tighten the loose screws in time. Ensure that the electrical and mechanical components inside the motor are firmly connected to avoid abnormalities caused by looseness‌.

‌4.Monitor the motor temperature‌: When the stepper motor is running, it is necessary to monitor whether its temperature is moderate. Avoid running the motor in a high temperature environment, ensure that the motor runs in a suitable application environment, and avoid the impact of high temperature on the motor‌.

‌5.Avoid overload operation‌: Reasonably control the power supply voltage and current to avoid damage to the motor caused by overload operation. Ensure that the motor runs under the specified load to avoid shortening the service life due to overload.

‌6.Check the insulation performance‌: Regularly check the insulation performance of the motor to prevent safety hazards such as leakage. Ensure the dryness of the motor windings to avoid the influence of humid environment on the motor insulation material.

‌7.Abnormal situation handling‌: If the stepper motor makes abnormal noise or other abnormal conditions during operation, it should be stopped and checked immediately. The inspection content may include whether the coupling, pulley, fastening screws, etc. are loose, and whether the slider, slide rail, positioning sensor and line connection are normal. If an abnormality is found, it should be handled in time and the equipment should be restored to normal operation.

‌Reasons for abnormal noises in Worm Gearbox

1.Definition of Worm Gearbox

Worm Gearbox is a power transmission mechanism that uses a gear speed converter to reduce the number of revolutions of the motor to the required number of revolutions and obtain a larger torque. It is widely used in the transmission systems of various machines, such as vehicles, heavy machinery, processing machinery, automated production equipment, and home appliances. ‌

2.Working principle of Worm Gearbox

Worm Gearbox achieves speed reduction and torque increase through the meshing of the worm and worm wheel. The worm is a cylinder with spiral teeth, and the worm wheel is a spiral gear. When the worm rotates, its spiral teeth mesh with the spiral teeth of the worm wheel, thereby achieving the effect of speed reduction and torque increase.

3.Main components and functions of Worm Gearbox

1.Worm gear: This is the core transmission component of the reducer, and its main function is to transmit motion and power between two staggered axes. The worm is usually made of a harder material (such as alloy steel) to improve wear resistance, while the worm wheel is made of a softer material (such as cast iron or specially configured wear-resistant nickel bronze) to reduce friction and improve transmission efficiency.

‌2.Shaft and bearings: The main functions of bearings and shafts are power transmission, operation and efficiency. The parts on the shaft are axially fixed by shaft shoulders, sleeves and bearing caps. Deep groove ball bearings are usually used to bear radial loads and small axial loads. When the axial load is large, angular contact ball bearings, tapered roller bearings or a combination of deep groove ball bearings and thrust bearings are used.

‌3.Housing: The housing is an important component of the reducer and the base of the transmission parts. It should have sufficient strength and rigidity. It is usually made of gray cast iron. For reducers with heavy loads or impact loads, cast steel housings can also be used. The housing is made horizontally split along the axis, and the upper housing cover and the lower housing are bolted together.

‌4.Accessories‌: including oil cap/breather, end cap, oil seal, drain plug, oil mark cap/oil mark, etc. These accessories play an important role in lubrication, sealing, oil drainage, and oil quantity observation in the operation of the reducer. ‌

4.Reasons for abnormal noise in Worm Gearbox ‌

1.Worm gear wear: After long-term use, the worm gear and worm gear may wear, resulting in poor meshing and noise. The degree of wear can be detected by visual inspection or using measuring tools. If the wear is severe, a new worm gear and worm gear need to be replaced. ‌

2.Bearing damage or poor lubrication: Bearing fatigue or insufficient lubrication can cause metal peeling on the bearing surface and produce abnormal noise. Ensure that the bearing is well lubricated, add or replace lubricating oil if necessary, and if the bearing is severely damaged, a new bearing needs to be replaced. 

‌3.Improper use of lubricating oil: Insufficient lubrication or use of the wrong lubricating oil will increase friction, resulting in noise. Check the oil level and oil quality to ensure that the lubricating oil is sufficient and of good quality. If the lubricating oil is deteriorated or contaminated, a new lubricating oil needs to be replaced. ‌ 

‌4.Improper installation‌: Unsteady installation of the Worm Gearbox or loose connections can cause vibration and noise. Make sure the Worm Gearbox is firmly installed and well-aligned to avoid vibration and noise caused by misalignment.

‌5.Overload‌: Worm Gearbox running at a load exceeding the rated load can cause overheating and increased noise. Check the load conditions to ensure that it is running within the normal range.

‌6.Mechanical failure‌: Some mechanical failures such as severely worn gears and loose connection parts can also cause noise in the Worm Gearbox. Perform a comprehensive inspection and repair or replace the faulty parts.

‌7.Foreign matter intrusion‌: When the Worm Gearbox is running, foreign matter such as dust and accumulated water in the surrounding environment may enter the reducer, causing poor meshing of the worm gear and noise. Make sure the environment around the Worm Gearbox is clean to prevent foreign matter from entering.

‌8.Design and manufacturing defects‌: Gear processing errors, unreasonable tooth shape design, etc. can cause poor meshing and noise. Choose a reliable quality reducer brand and model to avoid design and manufacturing defects.

Source:https://plaza.rakuten.co.jp/stepperonline/diary/202502100000/