Time：2020.05.22 Source：Roller Bearings Suppliers
The vibration system composed of steel, flexibility, mass, damping, etc. determined by the design parameters of the bearing structure will generate vibrations that are compatible with its mechanics under operating conditions.
The vibration caused by the deviation in the manufacturing process, the smaller the deviation, the smaller the vibration. The roundness, waviness and surface roughness of the surface of the steel ball are the factors that have the greatest impact on the vibration of each bearing part, followed by the shape error and surface roughness of the inner and outer ring channels, and again the bearing cleanliness and lubricant Quality etc.
Operating conditions such as installation conditions, speed, direction of load received in the axial direction, magnitude, etc.
What are the physical quantities of bearing vibration ?
The physical quantities of bearing vibration include vibration displacement, vibration speed, and vibration acceleration.
What is the vibration level and applicable range of bearings?
Bearing vibration (acceleration) is divided into Z, Z1, Z2, Z3 four levels;
Bearing vibration (speed) is divided into four levels: V, V1, V2, and V3.
The Z and V grades are suitable for bearing manufacturers' vibration inspection of deep groove ball bearings within the scope of the standard;
Z1 and V1 grades are suitable for the inspection of bearing products with general requirements for bearing vibration;
Z2 and V2 grades are suitable for Y series motors and other motor bearings with corresponding requirements;
The Z3 and V3 levels are applicable when there are strict requirements for vibration. This level has the international advanced level.
How to install tapered roller bearings
1.How to install tapered roller bearings:
Bearing installation must be carried out under dry, clean environmental conditions. Before installation, the machining quality of the mating surface of the shaft and the housing, the end surface of the shoulder, the groove and the connecting surface should be carefully checked. All mating and connecting surfaces must be carefully cleaned and deburred. Uncast surfaces of castings must be free of residual molding sand.
The bearings should be cleaned with gasoline or kerosene before installation, and used after drying, and to ensure good lubrication. The bearings are generally greased or oil lubricated. When using grease lubrication, high-quality grease with no impurities, anti-oxidation, anti-rust and extreme pressure should be selected. The amount of grease filled is 30% -60% of the volume of bearings and bearing boxes, and should not be excessive. The double-row tapered roller bearing with sealing structure and the shaft coupling bearing of the water pump have been filled with grease, and the user can directly use it, and can no longer clean it.
When the bearing is installed, an equal pressure must be applied to the circumference of the end surface of the ring to press the ring in. Do not directly hit the end surface of the bearing with a tool such as a shank to avoid damage to the bearing. In the case of a small amount of interference, you can press the end face of the bearing ring with a sleeve at normal temperature, tap the sleeve with a shank, and press the ring evenly through the sleeve. If installed in large quantities, a hydraulic press can be used. When pressing in, ensure that the end face of the outer ring and the shoulder face of the outer shell, the end face of the inner ring and the end face of the shaft shoulder are pressed tightly, and no gap is allowed.
When the interference is large, it can be installed by oil bath heating or sensor heating bearing method. The heating temperature range is 80 ℃ -100 ℃, and the maximum can not exceed 120 ℃. At the same time, nuts or other suitable methods should be used to tighten the bearings to prevent the bearing from shrinking in the width direction and causing a gap between the ferrule and the shaft shoulder.
The single row tapered roller bearing should be adjusted for clearance at the end of installation. The clearance value should be specifically determined according to different operating conditions and the amount of interference. If necessary, it should be tested to determine. The double row tapered roller bearing and the pump shaft bearing have been adjusted the clearance at the factory, and no need to be adjusted during installation.
After the bearing is installed, a rotation test should be carried out. First, the shaft or bearing box is rotated by hand. If there is no abnormality, the power is used to perform unloaded and low-speed operation. Then, the rotation speed and load are gradually increased according to the operation, and noise, vibration and temperature rise are detected , Found abnormal, should stop running and check. It can be delivered for use only after the normal operation test.
When the bearing is intended to continue to be used after being removed, an appropriate disassembly tool should be used. When disassembling the interference fit inner ring, only the pulling force can be applied to the ring, and the disassembly force must never be transmitted through the rolling element (outer ring), otherwise the rolling element and the raceway will be crushed.
3.The use environment of the bearing:
According to the use of parts and conditions of use and environmental conditions, select the size, accuracy, and suitable bearings are the premise to ensure bearing life and reliability.
Application parts:Tapered roller bearings are suitable for bearing combined radial and axial loads that are mainly radial loads, usually paired with two sets of bearings, mainly used in front and rear wheels, active tapered gears, differentials, Transmission parts such as reducer.
Allowable speed:Under the environment of correct installation and good lubrication, it is allowed to be 0.3-0.5 times of the limit speed of the bearing. Under normal circumstances, the limit speed of 0.2 times is the most suitable.
Permissible tilt angle:Tapered roller bearings generally do not allow the shaft to be tilted relative to the housing hole. If tilted, the maximum is no more than 2 degrees.
Allowable temperature:Under the condition of bearing normal load, and the lubricant has high temperature resistance and sufficient lubrication, the general bearing is allowed to work at an ambient temperature of -30 ℃ --- 150 ℃.
4.Installation method of tapered roller bearing
(1)Installation method of thrust tapered roller bearing
Thrust cylindrical roller bearings and thrust needle roller bearings are suitable for low speed applications. Thrust tapered roller bearings are slightly flat. Thrust bearings mainly bear axial loads in the assembly and are widely used. Although the thrust bearing installation operation.
(2)How are gears and tapered roller bearings assembled?
The gear should be designed with axial positioning steps, and the outer ring of the bearing should be closed, and the outer side of the inner ring should be locked with a lock nut.
(3)How to install and adjust the clearance of tapered roller bearings?
Tapered roller bearings are generally used, both face-to-face and back-to-back. The clearance size should be determined according to the size of the bearing you choose and the transmission accuracy required by the mechanism. As for the adjustment method, it can be achieved by pressing back to loose.
Tapered roller bearings are separable bearings, the inner and outer rings can be separated. Therefore, during installation, the inner ring cage rolling element assembly can be pressed on the shaft, and the outer ring can be installed separately in the bearing seat hole. When using the sleeve to press-fit, it should be noted that one end of the sleeve must be placed on the end face of the outer ring and not on the inclined raceway surface.
Tapered roller bearings are mostly installed in pairs. In the installation, we should focus on three aspects: choose the installation fit; adjust the axial clearance; perform trial operation and check the temperature.
5.Adjust the axial clearance
For the installation of tapered roller bearings, the axial clearance can be adjusted by adjusting the nut on the journal, adjusting the gasket and the thread in the bearing housing hole, or by preloading the spring and other methods. The size of the axial clearance depends on the arrangement of the bearing installation, the distance between the bearings, and the material of the shaft and the bearing seat, and can be determined according to the working conditions. For tapered roller bearings with high load and high speed, when adjusting the clearance, the effect of temperature rise on the axial clearance must be considered, and the amount of clearance reduction caused by the temperature rise must be estimated, that is, the axial clearance It should be adjusted appropriately. For bearings with low speed and vibration, it should be installed without clearance or pre-loaded. The purpose is to make the rollers and raceways of the tapered roller bearings make good contact, and the load is evenly distributed to prevent the rollers and raceways from being damaged by vibration and shock. After adjustment, the size of the axial clearance is checked with a dial indicator. The method is to first fix the dial indicator on the fuselage or bearing seat, so that the dial indicator contacts the smooth surface of the shaft, and push the shaft left and right along the axis, the maximum swing of the dial is the axial clearance value.