Maintenance of electric variable speed drive axle

Maintenance of electric variable speed drive axle

With the continuous development of new energy vehicles, electric variable speed drive axle, as one of its core components, plays a vital role in the performance and reliability of vehicles. For international wholesale buyers, understanding the maintenance knowledge of electric variable speed drive axle will help customers provide better after-sales support and enhance the competitiveness of products. This article will provide detailed maintenance points of electric variable speed drive axle from multiple aspects.

1. Basic knowledge of electric variable speed drive axle
1.1 Structural composition
The electric variable speed drive axle is mainly composed of motor, speed change mechanism, differential, bridge housing, half shaft and other parts. The motor provides power, the speed change mechanism realizes the switching of different gears to meet the needs of the vehicle under different driving conditions, and the differential is used to adjust the speed difference of the wheels on both sides when the vehicle turns. The bridge housing and half shaft are responsible for transmitting power to the wheels.
1.2 Working principle
During the driving process of the vehicle, the motor converts electrical energy into mechanical energy, transmits power to the differential through the transmission and transformation of the speed change mechanism, and then distributes it to the left and right half shafts by the differential, and finally drives the wheels to rotate to realize the driving of the vehicle. Its control system will automatically adjust the motor speed and the gear position of the transmission mechanism according to the vehicle speed, accelerator pedal position and other signals to achieve the best driving performance and energy efficiency.

2. Daily maintenance
2.1 Appearance inspection
Regularly check the appearance of the electric variable speed drive axle to check whether there is obvious damage, deformation, leakage and other phenomena. If there is oil leakage, it may be caused by damage to the oil seal or loose connection parts. The cause should be found out and handled in time. At the same time, check whether the bridge housing has cracks, whether the bolts and nuts in various parts are loose, and if they are loose, they should be tightened according to the specified torque.
2.2 Lubricant inspection
Maintaining the amount and quality of lubricant is crucial for the normal operation of the electric variable speed drive axle. Check the oil level of the lubricant, which should not be lower than 15mm below the bottom edge of the inspection hole. If the oil is insufficient, add lubricant of the same specification in time. At the same time, regularly observe the color and texture of the lubricant. If the lubricant is found to be black, thick or has impurities, it should be replaced in time. It is generally recommended to replace the lubricant every certain mileage (such as 20,000-40,000 kilometers) or every other year.
2.3 Tire and axle inspection
Check the tire pressure and wear to ensure that the tire pressure meets the specified standards, the wear is even and does not exceed the wear limit. Too high or too low tire pressure will not only affect the vehicle’s handling performance and comfort, but also increase tire wear and may even cause abnormal stress on the electric transmission drive axle. At the same time, check whether the axle is bent or cracked, and whether the keyway is excessively worn. If there is visible keyway wear, the left and right axles should be replaced.
2.4 Breather plug inspection
Ensure that the breather plug of the rear axle housing is unobstructed to avoid excessive or low pressure in the axle housing due to poor ventilation, which will affect the normal circulation of the lubricant and the lubrication effect of the gears.

3. Regular maintenance
3.1 Axle shaft maintenance
In addition to daily appearance inspection and keyway wear inspection, remove the wheel hub regularly to check whether the axle shaft sleeve has loose fit and cracks. The damage of each thread shall not exceed 2 teeth. If there is any problem, the axle shaft should be replaced in time.
3.2 Main reducer and differential maintenance
After draining the oil, remove the rear axle housing cover, clean the oil scum and check the tightness of the gears, bearings and bolts of each part. Check whether the oil seal of the main reducer is leaking, whether the flange nut is loose, and check the tightness of the main reducer connecting bolts. At the same time, check the tightness of the wheel hub bearing and tighten it according to the requirements of technical conditions if necessary. In addition, check whether the main reducer has abnormal noise and whether the meshing clearance is too large. If there is any abnormality, the meshing clearance should be adjusted and the tooth surface engagement should be checked. If the oil temperature exceeds 60℃ and is accompanied by abnormal noise during normal operation, it may be improper gear meshing, broken teeth on the gear or excessive bearing preload. The main reducer and differential need to be disassembled and inspected.
3.3 Speed ​​change mechanism maintenance
Check the wear of gears, synchronizers and other parts in the speed change mechanism. If there is obvious wear or damage, they should be replaced in time. At the same time, check whether the operating mechanism of the speed change mechanism is flexible and reliable, and whether the gear position is clear and accurate. If there is a jam or random gearing phenomenon, it should be repaired or adjusted.

4. Lubricant management
4.1 Selection of lubricants
The lubricant of appropriate type and quality grade should be selected according to the manufacturer’s recommendation of the electric variable speed drive axle and the vehicle’s instruction manual. Generally speaking, electric vehicle drive axles often use gear oils with high viscosity index and extreme pressure and anti-wear properties to meet the high speed and high torque working requirements of the motor. At the same time, they have good anti-oxidation, anti-foaming and anti-corrosion properties to extend the service life of the lubricant and protect the drive axle components.
4.2 Replacement of lubricants
When replacing the lubricant, make sure to do it when the vehicle is in a hot state, which is conducive to the discharge of the old oil. At the same time, the old oil in the drive axle should be thoroughly drained, and the oil pan and magnetic oil plug should be cleaned to remove impurities and metal chips. When adding new oil, pay attention to the control of the oil volume to avoid too much or too little. In addition, do not mix lubricants of different brands and models to avoid chemical reactions caused by differences in the performance of the lubricants, which will affect the lubrication effect.

5. Electrical system maintenance
5.1 Motor inspection
Regularly check whether the appearance of the motor is damaged or deformed, and whether the motor is firmly installed. Check whether the wiring of the motor is loose, short-circuited or aging. If there is a problem, it should be repaired or replaced in time. At the same time, test the insulation resistance of the motor to ensure that it meets the specified requirements to ensure the normal operation and safety of the motor. The insulation resistance of a general motor should not be less than 1 megohm.
5.2 Control system inspection
Check the control system of the electric variable speed drive axle, including controllers, sensors, circuits and other components. Ensure that the controller is firmly installed, the heat dissipation is good, the terminal connection is reliable, and there is no looseness or oxidation. Check whether the sensor is installed in the correct position and works properly, such as the vehicle speed sensor, motor speed sensor, etc. If there is a fault, it will affect the normal driving and speed change function of the vehicle. In addition, check whether the insulation layer of the circuit is damaged or aged, whether the wiring harness is loose or interfered, etc. If there is a problem, it should be handled in time to prevent the electrical fault from causing the drive axle to fail to work properly.

6. Fault diagnosis and troubleshooting

6.1 Common faults and causes

Abnormal noise: Possible causes include gear wear, bearing damage, improper meshing clearance, insufficient or deteriorated lubricating oil, etc. Abnormal noises in different parts and types have different characteristics. For example, abnormal noises in gear meshing usually appear as regular “buzzing” or “clicking” sounds, and abnormal noises caused by bearing damage may be continuous “rustling” or “clattering” sounds.

Overheating: It may be caused by insufficient lubricating oil, poor oil quality, poor heat dissipation, excessive bearing preload, improper gear meshing, etc. During the driving process of the vehicle, if the temperature of the drive axle is found to be too high, it should be stopped and checked in time.

Oil leakage: It is mainly caused by damaged oil seals, aging sealants, loose connection parts, etc. Check the location and severity of the oil leakage for targeted repairs.
Difficulty or failure in shifting: It may be caused by the failure of the operating mechanism of the transmission mechanism, wear of the synchronizer, control system failure, motor failure, etc. When shifting gears, if there are difficulties in shifting gears, random gears, and gear jumping, it will affect the normal driving of the vehicle.
6.2 Fault diagnosis method
Auscultation method: By using tools such as stethoscopes, close to different parts of the drive axle, listen to the source and characteristics of abnormal noises, and preliminarily determine the fault location and cause.
Observation method: Observe the driving status of the vehicle, instrument indicators, fault indicators, etc., and check the appearance, oil, connection parts, etc. of the drive axle to find abnormal signs.
Detection method: Use professional automotive testing equipment, such as decoders, oscilloscopes, multimeters, etc. to detect the control system, motor, sensor, etc. of the drive axle, read fault codes and related data streams, and analyze the cause of the fault.
Road test method: Conduct road tests under different road conditions and driving conditions to feel the driving performance of the vehicle and the working status of the drive axle in order to find problems.
6.3 Troubleshooting Cases
Case 1: Abnormal noise fault: When a new energy vehicle was driving, the electric variable speed drive axle had abnormal noise. Through auscultation, it was found that the abnormal noise mainly came from the main reducer, and the abnormal noise was obvious when the vehicle accelerated and decelerated. After inspection, it was found that the gear meshing clearance of the main reducer was too large, resulting in gear tooth impact and abnormal noise. By adjusting the meshing clearance of the gears, reassembling and adding appropriate lubricating oil, the abnormal noise fault was eliminated.
Case 2: Overheating fault: After a certain electric vehicle was driven for a period of time, the electric variable speed drive axle overheated. Inspection found that the amount of lubricating oil was insufficient and the oil quality was deteriorating. At the same time, there was a lot of dust and debris on the surface of the radiator, which affected the heat dissipation effect. After cleaning the radiator and replacing the lubricating oil, the temperature of the drive axle returned to normal.

7. Maintenance cycle and records
7.1 Maintenance cycle
Develop a reasonable maintenance cycle based on the vehicle’s instruction manual and actual usage. Generally speaking, routine maintenance can be performed weekly or monthly, including appearance inspection, lubricant inspection, tire and axle inspection, etc.; the period of regular maintenance can be determined according to the mileage or usage time of the vehicle, such as first-level maintenance every 10,000-20,000 kilometers or every six months, and second-level maintenance every 30,000-60,000 kilometers or every year.
7.2 Maintenance Records
Establish a detailed maintenance record file to record the time, content, replaced parts, amount of lubricant added and model of each maintenance. This helps to track the maintenance history of the electric variable speed drive axle, discover potential problems in time, and provide a reference for subsequent maintenance and repairs.

8. Safety Precautions
Before performing maintenance work on the electric variable speed drive axle, be sure to ensure that the vehicle is in the off state and disconnect the power supply to prevent electric shock and accidental start.
Use appropriate tools and equipment, and avoid using damaged or non-standard tools to avoid damage to parts or personal injury.
When removing and installing parts, pay attention to the correct order and method to avoid damage to parts or assembly errors due to improper operation.
For some professional maintenance and repair work, such as the adjustment of the transmission mechanism and the inspection of the motor, it should be performed by professional technicians with relevant qualifications and experience to ensure safety and repair quality.

Through the above comprehensive maintenance introduction of the electric variable speed drive axle, it is hoped that it can help international wholesale buyers better understand its maintenance points, so as to provide customers with better products and services, improve product reliability and customer satisfaction. The maintenance of the electric variable speed drive axle is a systematic project that needs to be carried out regularly and meticulously. Only in this way can it ensure that it always maintains good performance and operating status during the driving process of the vehicle.