Application of new energy drive motor bearing design characteristics

Application of new energy drive motor bearing design features - 2019 10 - 19 new energy electric vehicle was developed by countries in recent years, advocate green environmental protection, zero emission of new energy vehicles, the drive motor, battery, the controller is the core component of new energy vehicles, is the heart of new energy vehicles. Rolling bearing is the drive motor, the rotating parts with high speed, high temperature, frequent start-up shock is the main mode of electric vehicle drive motor development can adapt to the working conditions of the series sealed deep groove ball bearings, can satisfy the hybrid buses, pure electric bus, pure electric passenger cars, electric minivans and a series of new energy vehicles drive motor used. And is widely used in the market. Design features: new energy drive motor bearing design considering the good sealing performance, high temperature performance, low temperature performance, repeated start-stop performance, such as certain axial impact load conditions, internal structure, optimize the product fully consider the bearing material, heat treatment, machining accuracy, grease, cooperate with impact on product installation, make the product performance is improved greatly, the limit speed can reach 1 to conventional bearing limit speed. More than 5 times. 1 RPM speed affect the service life of bearing and grease at the same time. Therefore, must be considered when choosing bearing bearing size, type of cage, the lubricating way, clearance and seal type. Currently used in the new energy automobile drive motor of up to 18000 RPM, DMN value can reach more than 800000. 2 axis and shell material because of the expansion and contraction, when choosing axis and shell material, consider mainly the expansion coefficient. Heat and cold will directly affect the shaft and housing, which affect the bearing internal clearance. Drive motor shaft in the field of materials used and quenched and tempered medium carbon steel processing, shell usually adopts cast aluminum or aluminum alloy materials, which can reduce motor overall weight, also can greatly increase the cooling speed. 3 in damp environment, low temperature, high temperature, and a large amount of mud, dust environment, it is particularly important to seal and seal materials. Need to consider the packing of the product; Damage to the environment and the product to prevent oil leak, the leak of the grease will cause bearing oil shortage at the same time, affect the service life of the bearing. 4 temperature bearing temperature is one of the main reasons affecting the service life of the machine. When the environment temperature and bearing temperature when the temperature difference is very big, bearing temperature gradient is produced. If the temperature gradient is very big, should check bearing internal clearance, in order to avoid unnecessary damage of bearing. 5 keep new energy cars drive motor high-speed bearing adopts high temperature resistant, ≥ 180℃） Engineering plastic cage, low-speed bearing used in (SPCC) cage, cage has a good performance of high performance and low noise. 6 bearing accuracy of new energy vehicles drive motor bearing precision grades are up to the level of the P6, internal parameters can achieve the P5, the rotation of the high stability and low noise performance ( The noise level of Z3 group) 。 7 bearing life rating life of rolling bearing is defined as: in the bearing ring and rolling body fatigue appeared for the first time ( Peeling or fracture) Signs of former, bearing can achieve revolution ( Or under a constant rotational speed running hours) 。 Laboratory test data and practical experience shows that on the surface of the same bearing running under the same conditions will still have a different life. In general, the bearing life depends on its operating conditions, however, bearing installation and maintenance program will have direct influence on the service life of bearing, although there are many preventive measures, bearing will still be failure in advance. When this happened, check carefully to determine the root cause of the failure of the bearing. To complete the root cause analysis to corrective measures. Target is manufacturer based on load and speed ideal life value is given a life. For example: the maximum allowable load under life of lowest of 5000 hours, or a year. In good running condition, can achieve than ordinary or traditional bearing life calculation expected a longer life expectancy. When the lubricating film can effectively separate rolling surface ( Raceway and rolling body) , or when the damage caused by pollutants surface is very limited, will be able to achieve good operating condition. （ Source: EDC electric drive in the future)