One of the most important differences between automotive bearings and ordinary mechanical bearings is that they are used in a moving environment.Because the automobile bearing is a very precise mechanical parts, plus its force, the complex working condition, make it in the installation, use, lubrication and maintenance is particularly important.Today, we will give you a brief introduction, the installation of car bearings, please read carefully!
1. Clean the bearing and relevant parts with it with clean kerosene or gasoline;
2. Check whether the bearing to be used and its related parts are consistent with the original model and the size is qualified;
3. Press the bearing into the assembly tool sleeve with a special assembly tool sleeve (note: the diameter of the tool sleeve should not exceed the outer diameter of the bearing retaining edge). During assembly, the force should be uniform, and the impact or brutal assembly should not be allowed.
4. After the bearing is installed, the bearing and its related parts should be rotated to see if there is any jamming phenomenon and abnormal noise;
5. According to the requirements of the main engine parts, the specified grease or lubricating oil shall be injected at the appropriate time and place.
Maintenance knowledge of automotive bearings:
The bearings used in the automobile are mainly rolling bearings, which are widely distributed and have more chances of failure. Therefore, it is the focus of maintenance.The maintenance of rolling bearings can be divided into three aspects: inspection, lubrication and adjustment.
I. bearing inspection
Before the bearing is assembled, its appearance should be inspected to determine whether the bearing can continue to be used.
1.Rotate the clean bearing, inspect the rolling body and inner and outer raceway, and replace any pitting or ablation.
2.Rotate the bearing several times, check and listen to whether the rotation sound of the bearing is uniform or not, observe whether the bearing frame is deformed, whether individual rolling body is too worn;The disassembled bearing (from which the rolling body falls off) shall be replaced.
3.Check whether there are obvious indentation in the inner and outer raceway of the bearing (especially the original dimension bearing), the appearance of indentation will directly affect the adjustment of the preload, the bearing with obvious indentation should be replaced.
4.Check whether the bearing fits the shaft and bearing hole to meet the requirements.For the bearing with loose kuang, to analyze the cause, if it is related to the bearing, should be replaced.Needle roller bearing should check whether its fit clearance is normal, the clearance should not be greater than 0.10mm.
Ii. Bearing lubrication
The quality of bearing lubrication directly affects the service life of the bearing, and then affects the work stability and maintenance cycle of the assembly.
1.Oil lubricated bearings
Oil lubricated bearings, generally good lubrication, no special attention.But the lubricating oil should be added as required.
2.Grease lubricated bearings
Due to the dispersity and arbitrariness of the grease to the bearing lubrication, attention should be paid to it.
(1) the amount of grease added into the bearing shall be appropriate.The amount of grease should be 1/3~2/3 of the bearing voids.Too much grease is easy to overheat the bearing and cause the grease to dissolve.Too little grease does not form a good film.The bearing with high speed should take its lower limit, the bearing with low speed should take its upper limit.The amount of hub bearing grease shall ensure the filling of about 2/3 of the bearing void, and the hub between the two bearings shall not be filled with grease.The filling amount of high speed rotating bearings such as generator and water pump is 1/3 of the void.
(2) the grease shall be selected correctly.The type of grease to be used shall be selected according to the requirements of the automobile operating manual.Because of the characteristics of high drop point and good performance at low temperature, the lithium grease can meet the requirements for the use of automobile bearings (the lithium grease can be divided into no. 1, no. 2 and no. 3 according to the cone penetration degree), the automobile bearings should choose no. 2 lithium grease.
(3) determination of grease replacement period.The premise of grease replacement is before the grease hardening and deterioration.Because the use environment of each bearing of the automobile is different, the convenience of filling the grease is different, so on the one hand, the grease should be replaced according to the maintenance mileage of the car;On the other hand, the grease can be changed at any time according to the degree of noise in the operation of the car bearing.For pump bearing, transmission shaft cross bearing, the replacement period of grease is correspondingly shorter.
3.Lubricating oil is mixed with grease for lubrication
Pressure bearing used on the car (such as clutch separation bearing, etc.), general lubrication filling is difficult, so it is necessary to use the method of mixed lubrication filling, commonly known as "boiled bearing".The method is to take equal parts of the oil and grease, mixed heating to make the grease dissolved, the bearing immersed in which soaked for several hours, and then out for use.However, it should be noted that for oil-bearing pressure bearings, there is no need for additional lubrication, such as the domestic 9688211 bearings.
Iii. Adjustment of bearing
Each pair of bearings needs to be adjusted after loading.One is to adjust the coaxiality with the shaft, the other is to adjust the preload of the bearing.
In order to ensure that the shaft is in the correct working position, the bearing should be in good alignment with the shaft during assembly.
(1) positioning device by bearing (clamping ring of bearing outer ring and shaft shoulder on shaft, etc.).Before mounting the bearing, check whether the clasp is good and reliable, whether the shaft shoulder is flat, and whether there are impurities on the surface.
(2) aligning the bearing through test operation.Before the bearing cover fastening bolt is tightened and the torque does not reach the specified value, make the bearing in a semi-free state to test rotation, and make it "automatic" alignment.After the test rotation, tighten the fastening bolt according to the specified torque, such as the middle support bearing of the transmission shaft.
2.Adjustment of bearing preload
The support rigidity of rolling bearing can be improved by reasonable pretightening of bearing.The principle of bearing preload is to force the bearing to produce a certain axial displacement between the inner and outer rings, so as to achieve the purpose of preload.Preload adjustment of the bearing should be flexible rotation, no stuck phenomenon, axial push, pull, pry should be no obvious gap feeling is appropriate.There are two ways to adjust the preload: thread adjustment and gasket adjustment.
(1) thread adjustment method.It is through the screw in, screw out nuts or studs to adjust the bearing preload, such as steering machine bearings, hub bearings.It is easier to adjust the thread, but attention should be paid to the adjustment bolts or nuts to lock, in order to prevent loose and change the preload has been adjusted.
(2) gasket adjustment method.It is through the increase and decrease of the bearing, the outer ring of the thrust gasket to achieve the purpose of pre-tightening, such as driving axle bearings.During adjustment, it should be noted that the increase or decrease of gasket shall not affect the overall assembly quality.For example, if the drive axle bearing adjustment pad increase or decrease improper, will destroy the bevel gear meshing imprint.
Iv. Matters needing attention for bearing replacement
1.Bearing side marked with bearing number, the replacement of new bearing should be according to this number.
2.The bearing of the broken frame shall be replaced with the inner and outer rings at the same time, not only the bearing frame and rolling body.
3.It is advisable to choose the same type bearing with the imported bearing matching with the original vehicle, if the choice of domestic bearing need to consult the relevant manual and instructions, according to the corresponding model.
To sum up, as long as the bearing careful inspection, reasonable adjustment, to ensure that the car in safe, high-speed conditions to lay a good foundation, but also to protect the other parts and assembly connected with it in a good state.Hope to attract the attention of the peers.