As an important part of the automobile, the function of the gearbox is important, and the quality of the bearing can directly affect the quality of the gearbox assembly, even the normal play of the vehicle's driving performance. In this paper, the type, application and damage form of the bearing in the variable belt box are thoroughly analyzed and discussed, which is intended to provide some useful reference for the quality assurance of the variable belt box in the domestic automobile manufacturing enterprises.
The quality of the bearings in the car gearbox is very important for the normal operation of the car, although it seems that it does not seem that the engine, transmission shaft and other parts of the bearing or accessories appear more important, but the quality of the transmission inside the bearings for the overall performance of the vehicle, the slightest slightest a slightest sloppy. The author analyses and proves the should be shipped, damage and cause of the bearing in the automobile gearbox, and intends to make some useful explorations for the fault diagnosis of the automobile gearbox.
1. Auto Gearbox function
Automobile Gearbox main function now, through the driver operation, to achieve the car gear adjustment, such as neutral, reverse gear, and so on, its fundamental aim is to change the engine, drive wheel between the transmission ratio, so that the engine mechanical traction, travel speed can meet the various conditions of the car, to achieve vehicle forward, backward, stop and so on.
2. Bearing action in machinery
In any kind of machinery, as long as the use of the bearing, its main function is: to provide the corresponding supporting role is the main part, its essence is to bear the radial load. Also, the shaft can be fixed, so that the shaft can not go into action, axial movement, so that the shaft only to rotate. It is necessary to lubricate the bearings based on the good operation of the bearings and the need to reduce the undesirable interference formed by the bearing on the high-speed shaft.
3. Bearing types and operation analysis in transmission
3.1 Needle roller bearings, this bearing due to the radial size is small, compact structure, so it can withstand a large amount of load, usually, if the supporting components of the radial installation of the size of the constraints, the bearings have a useful position. Its biggest do point is to realize the miniaturization of machinery and equipment development direction.
3.2 Tapered roller bearings, the bearings are generally used in the radial load to withstand the main radial and axial load of the joint, tapered roller bearing capacity is relatively large, but its fatal defect table now, the operation of the voice is too large, the manufacturing accuracy is not too high, if the requirements of the machine voice small, high speed, do not advocate the use of such bearings, Because it simply does not meet this requirement.
3.3 Cylindrical roller bearings, which are typically used to withstand radial loads, are extremely convenient for mounting and dismounting of cylindrical roller bearings and are separable bearings. Compared with deep groove bearings, the stiffness and radial bearing capacity of cylindrical roller bearings are relatively large, so generally in the high stiffness requirements of equipment or, in the higher load equipment, the use of this bearing is usually more.
3.4 Deep groove ball bearings, this kind of bearing because of its relatively simple results, easy to use, and its use is quite extensive. Most will apply to the need for radial load bearing aspect, of course, it can also be under certain conditions to bear a certain axial load. However, once the radial clearance is too large, deep groove ball bearings will have the same characteristics as angular contact ball bearings. The advantages of this kind of bearing is that the manufacturing accuracy is good, limited speed express, easy to complete the bearing seal, friction coefficient is not so, the country has many advantages for its wide range of uses.
4. Gearbox Requirements for bearings
As a key part of the vehicle, the gearbox requirements for the bearings are as follows:
First of all, the output power is big, the noise is small, secondly, some bearings need to withstand axial force; again, because the gearbox working time is generally relatively long, so the requirements of the bearing capacity must be large enough, and, it is required to be able to withstand high load operation, but also to adapt to a variety of load changes, withstand long-time operation At last, because the gearbox volume is limited, the bearing size needs to be small, the weight should be light, the structure should be compact. Bearings must have these characteristics to adapt to the continuous development of the automotive transmission needs, the future of the gearbox bearing operation requirements are based on the current characteristics.
5. Normal damage to the bearing in the gearbox
5.1 gluing damage, mainly refers to the bearing abnormal overheating caused by the bearings are glued to one place, can no longer achieve rotation, or, the rolling becomes jerky, rough, at this time, the hardness of the bearing becomes smaller, because the table due to rough will make the bearing rotation performance is reduced, or basically invalid;
5.2 Fracture damage, refers to the automobile gearbox due to poor lubrication conditions, long time, full load, high speed operation resulting in high shaft temperature, the phenomenon of holding shaft, at this time if continuous operation, it will damage the bearing;
5.3 Wear damage, mainly refers to the bearing ball, raceway between the relatively frequent operation, assembly abnormalities, the inclusion of debris into the bearing damage caused. Here, the bearing life directly depends on the size of the wear, too large, resulting in increased bearing clearance, ball (column) surface roughness, precision reduction, the noise becomes larger, the vibration amplitude also become larger, therefore, the transmission inside the noise will be obvious;
5.4 Corrosion damage, the cause of this type of bearing damage is that the transmission of lubricating oil used too long, deterioration, failure or corruption, so that the bearing surface corrosion, resulting in corrosion, and ultimately damage the bearing, however, this phenomenon occurs infrequently, because generally speaking, the amount of lubricating oil will be often detected, And car owners will often change lubricants;
5.5 Fatigue damage, this type of bearing damage is the main way of bearing damage in the gearbox. The reason is that the bearing balls are subjected to repeated and unbalanced loads in the cage, resulting in the deformation and roughness of bearing balls.
5.6 Adhesive damage, when the transmission of lubricating oil in no quantity, can not guarantee the normal bearing lubrication needs, the running of the bearing heat will not be effectively discharged, the final formation of the ball bearing, raceway surface adhesion was destroyed, resulting in bearing damage.
The above is simply a list of several major gearbox bearing damage, other reasons may also allow the transmission bearing lockout, which should be specific analysis of the situation.
The rapid development of the automobile industry makes the bearing application in the gearbox more popular and extensive. The improvement of the economic conditions makes the customer demand for the vehicle performance is also rising, if the bearing in the gearbox can not be sustained, efficient, fast operation, it can not guarantee the normal driving of the vehicle, but also can not guarantee the life of the vehicle owner safety. This requires bearing design, production, manufacturers in the development, production of bearings, must take into account a number of elements, such as working space, security, driver operating characteristics, etc., to consider, so as to develop a durable, durable, safe bearings.