Writer: Eric Bearing Limited
When choosing the type of NTN bearing, it is crucial to fully understand the operating conditions of the NTN bearing. Eric Bearing Limited tells you six points to note in choosing NTN bearings:
1.The installation space of NTN bearing can be accommodated in the installation space of NTN bearing. Due to the emphasis on the rigidity and strength of the shaft when designing the shaft system, the shaft diameter is generally determined first, that is, the inner diameter of the NTN bearing. However, rolling NTN bearings come in many sizes and types, and the most suitable NTN bearing type should be selected from them.
2.The relative tilt analysis of the inner ring and the outer ring causes the NTN bearing inner ring and outer ring to have a relative tilt factor (such as shaft deflection caused by load, poor accuracy of the shaft and housing or installation error), and choose to adapt to this Types of NTN bearing types. Therefore, the type of NTN bearing that can withstand such tilt should be selected. If the relative tilt of the inner ring and the outer ring is too large, the NTN bearing will be damaged due to internal load.
3.Load The size, direction and nature of the load of the NTN bearing [The load capacity of the NTN bearing is expressed by the basic rated load, and its value is contained in the NTN bearing size table] The load of the NTN bearing is rich in changes, such as the size of the load, whether it is only radial , Whether the axial load is unidirectional or bidirectional, the degree of vibration or shock, etc. After considering these factors, let's choose the most suitable NTN bearing type.
Generally speaking, the radial load capacity of NTN bearings with the same inner diameter increases in the following order: deep groove ball bearings <angular contact ball bearings <cylindrical roller bearings <tapered roller bearings <aligning roller bearings
4.The frequency of assembly and disassembly and the methods of assembly and disassembly, such as periodic inspection and installation. When assembly and disassembly are frequent, it is more convenient to use cylindrical roller bearings with separable inner and outer rings, needle roller bearings and tapered roller bearings.
Deep groove ball bearings, contact ball bearings, cylindrical roller bearings
The deformation of the roller bearing under load is smaller than that of the ball bearing. Preloading (negative clearance) on NTN bearings can increase rigidity. This method is suitable for angular contact ball bearings and tapered roller bearings.
5.The type of NTN bearing whose speed can adapt to the mechanical speed [The limit value reference of NTN bearing speed is expressed as the limit speed, and its value is shown in the NTN bearing size table] The limit speed of NTN bearing is not only taken from the type of NTN bearing but also limited to the size of NTN bearing, Cage type, accuracy grade, load conditions and lubrication method, etc. Therefore, these factors must be considered when selecting.
The following NTN bearings are generally used:
In general, the tilt angle (or centering angle) is allowed to increase in the following order:
Cylindrical roller bearings, tapered roller bearings, deep groove ball bearings (angular contact ball bearings), spherical roller (ball) bearings, NTN bearing types whose rigidity meets the rigidity required by the mechanical shafting [NTN bearings under load, The contact part of the rolling element and the raceway will be elastically deformed. "High rigidity" means that the amount of elastic deformation is small. In the machine tool spindle and automobile final stage deceleration device, the rigidity of the NTN bearing must be increased while increasing the rigidity of the shaft.
6.Rotation accuracy NTN bearing type with required rotation accuracy [The dimensional accuracy and rotation accuracy of NTN bearing have been standardized by GB according to NTN bearing type Machine tool spindle, gas turbine and control machine require high rotation accuracy, high speed and low speed respectively For friction, NTN bearings with grade 5 accuracy or higher should be used. If you look for NTN bearings , ERIC BEARING LTD can provide you , contact us freely .
NTN bearing disassembly and assembly skills maintenance method
1.Loosen the bolts holding the bearing housing. Remove the NTN imported bearing together with the bearing seat from the shaft. Note before removing the NTN bearing housing at one end of the shaft. The I bearing seat bolts at the other end of the shaft should be loosened to prevent the bearings at both ends from being stiff and damaged.
2.First use an Allen wrench to loosen the locking screw on the eccentric sleeve of the NTN bearing, then use a small iron rod to insert the counterbore on the eccentric sleeve of the top cover, and loosen the eccentric sleeve against the rotation direction of the shaft.
Many people use improper installation methods in the installation of bearings, resulting in damage to NTN bearings. So how to install NTN bearings correctly? I hope you can have a more comprehensive understanding of the installation and disassembly of bearings:
For bearing rings with clearance fits, it is recommended to apply a thin layer of anti-creep corrosion agent on the mating surfaces to prevent frictional corrosion between the mating surfaces.
390000 series spherical bearings are used to fix the inner ring of the bearing and the shaft through an eccentric sleeve. The hexagon socket screws on the eccentric sleeve play a tightening role. In the maintenance, many operators will not disassemble this NTN bearing, so it is necessary to introduce the technical points and precautions of disassembly and assembly of 390000 series outer spherical NTN bearings:
Correct installation is very important for the use of NTN bearings. I hope you can use the correct installation method in future use.
When installing, you can choose mechanical, heating or hydraulic methods according to its type and size. The force applied to the bearing during installation must not be transferred from one bearing ring to another NTN bearing ring through the rolling element, otherwise it may cause damage to the raceway. However, under no circumstances should you directly strike the bearing rings, cages, rolling elements or seals.
3.Install an eccentric sleeve. First put the eccentric sleeve on the eccentric step of the NTN bearing inner sleeve, and tighten it by hand along the rotation direction of the shaft. Then insert or hold the small iron rod into the countersink hole. Use a hammer to strike the iron rod in the direction of rotation of the shaft. Install the eccentric sleeve firmly, and finally tighten the hexagon socket screws on the eccentric sleeve.
4.Do not tighten the bolts that secure the NTN bearing housing, but allow the bearing housing to rotate in the bearing housing. Then tighten the bearing seat bolts. Also install the other end bearing and seat on the same shaft, turn the shaft a few times, and let the NTN bearing itself find the correct position automatically.
5.Apply lubricating oil to the mating surfaces of the bearing housing and the bearing, and install the NTN bearing in the bearing housing. Then put the assembled bearing together with NTN bearing seat on the shaft. Push to the desired location to install.
6.Before installing the NTN bearing on the shaft, you must first remove the fixing pin of the NTN bearing jacket, at the same time polish the surface of the journal smooth and clean, and apply oil to prevent rust and lubricate the journal (allow the bearing to rotate slightly on the shaft).
(1) Clean the dust on the fan to prevent dust from entering the bearing during installation;
(2) Tear off the seal of the bearing seal and remove the bayonet on the shaft;
(3) Wipe the residual oil in the bearing with a clean tissue or soft cloth, and then wipe the shaft;
(4) Put a little butter in the bearing, the principle is that it is better not to have less, so as not to seriously affect the speed;
(5) Cut the aluminum skin of the canister as big as the outer diameter of the bearing bayonet, and dig a small hole in the middle that can just pass through the shaft, and place it between the bearing and the bayonet. Reduce the distance of axial movement and parallel movement of the bearing. If the gap is large, it is necessary to pad a few thickenings, so that the front and rear movement distance of the bearing is less than 0.5mm;
(6) Seal the oil seal, add a little butter, and finally install the fan back to the graphics card. Try to connect the power supply, you will find that the sound is much lower, and in this way it can be used for at least 2 years. But it needs to be reminded that although the sound is lower, the speed will drop slightly due to the limited precision of the manual.