Yantai Bonway Manufacturer

Roller bearing

Roller bearing is a kind of rolling bearing, and it is one of the parts widely used in modern machinery. It relies on the rolling contact between the main components to support the rotating parts. Roller bearings are now mostly standardized. Roller bearings have the advantages of small starting torque, high rotation accuracy, and convenient selection.

definition:
Rolling bearings are divided into ball bearings and roller bearings according to the rolling force.
Roller bearings rely on the rolling contact between the main parts to support the rotating parts. Different roller bearings can withstand different radial and axial forces. When selecting roller bearings, the choice should be made according to specific working conditions.
Roller bearings mainly include spherical roller bearings, thrust spherical roller bearings, tapered roller and cylindrical roller bearings and other structural types.

Type selection:
When selecting bearings, the main considerations are as follows:
Bearing load
The size, direction and nature of the load on the bearing are the main factors for selecting the bearing.
When selecting the bearing according to the size of the load, compared with the point contact of the ball bearing, the main components in the roller bearing are in line contact, which is easy to bear the load and the deformation after the load is small.
When selecting bearings according to the load direction, for pure axial loads, thrust bearings are generally selected. For larger axial force, choose thrust roller bearings. Choose thrust ball bearings for smaller axial forces. For pure radial loads, deep groove ball bearings, cylindrical roller bearings or needle bearings are generally used. When bearing a radial load while still bearing a small axial load, deep groove ball bearings or tapered roller bearings can be selected; when the axial load is large, angular contact balls with larger contact angles can be selected Bearing or tapered roller bearing.
Bearing speed:
Under normal circumstances, the speed will not have any effect on the choice of bearing type, but when the speed is large, the speed should be included in the standard of bearing selection.
(1) Compared with roller bearings, ball bearings have a higher limit speed, so in the case of high speed, ball bearings are given priority.
(2) In the case of the same inner diameter, the smaller the outer diameter, the smaller the rolling elements, so the centrifugal force added to the outer ring by the rolling elements is smaller, so it is more suitable for working at high speeds. According to the given properties, needle roller bearings are more suitable for working at high speeds.

The self-aligning performance of the bearing:
When the center line of the shaft does not coincide with the center line of the bearing seat and there is an angular error, or when the shaft is bent or inclined due to force, the axis of the inner and outer rings of the bearing will be deflected. At this time, a self-aligning bearing with a certain degree of self-aligning performance or an outer spherical ball bearing with a seat should be used.
Roller bearings are most sensitive to the deflection of the bearing, and the load carrying capacity of this type of bearing under deflection may be lower than that of ball bearings. Therefore, when the shaft stiffness and the support stiffness of the bearing seat hole are low, or when there is a large deflection moment, the use of this type of bearing should be avoided as much as possible.
Bearing installation and removal
When the bearing seat has no split surface and components must be installed and removed in the axial direction, bearings with separable inner and outer rings (such as N0000, NA0000, 30000, etc.) should be preferred.

Lubrication method:
Lubrication is of great significance to the bearing. The lubricant in the bearing can not only reduce the friction resistance, but also play a role in heat dissipation, reducing contact stress, absorbing vibration, and preventing corrosion.
Commonly used lubrication methods for bearings are oil lubrication and grease lubrication. It is also lubricated with solid lubricants. Which lubrication method is selected depends on the speed of the bearing. Generally, the dn value of the bearing (d is the inner diameter of the bearing, mm; n is the speed of the bearing, r/min) indicates the speed of the bearing.

Cylindrical rollers and raceways are linear contact bearings. Load capacity, mainly bear radial load. The friction between the rolling element and the retaining edge of the ring is small, which is suitable for high-speed rotation. According to whether the ring has ribs, it can be divided into single row cylindrical roller bearings such as NU, NJ, NUP, N, NF, and double row cylindrical roller bearings such as NNU and NN. The bearing has a separable structure with inner ring and outer ring.
Cylindrical roller bearings with no ribs on the inner ring or outer ring, the inner ring and outer ring can move relative to the axial direction, so it can be used as a free end bearing. Cylindrical roller bearings with double ribs on one side of the inner ring and outer ring and a single rib on the other side of the ring can bear a certain degree of axial load in one direction. Generally use steel stamping cage or copper alloy car solid cage. But there is also a part of the use of polyamide forming cage.
Bearing features:
1. Roller and raceway are in line contact or repaired offline contact, with large radial load capacity, suitable for bearing heavy load and impact load.
2. The friction coefficient is small, suitable for high speed, and the limit speed is close to the deep groove ball bearing.
3. The N type and NU type can move axially, can adapt to the change of the relative position of the shaft and the housing caused by thermal expansion or installation error, and can be used as a free end support.
4. The processing requirements for the shaft or the seat hole are high, and the relative deviation of the outer ring axis after the bearing is installed must be strictly controlled to avoid contact stress concentration.
5. The inner ring or outer ring can be separated for easy installation and disassembly.
product features:
The cylindrical roller is in line contact with the raceway, and the radial load capacity is large. It is not only suitable for bearing heavy load and impact load, but also suitable for high-speed rotation.
The raceways and rolling elements of cylindrical roller bearings are geometrically shaped. After the improved design, it has a higher load-carrying capacity. The new structural design of ribs and roller end faces not only improves the axial load-carrying capacity of the bearing, but also improves the lubrication conditions of the contact area between the roller end faces and the ribs. The performance of the bearing.
Mainly used for large and medium-sized motors, locomotives, machine tool spindles, internal combustion engines, generators, gas turbines, reduction gearboxes, rolling mills, vibrating screens, and lifting and transporting machinery.

Spherical roller bearings have two rows of rollers, which mainly bear radial load, but can also bear axial load in any direction. With high radial load capacity, it is especially suitable for working under heavy load or vibration load, but it cannot bear pure axial load. The outer ring raceway of this type of bearing is spherical, so its alignment performance is good, and it can compensate the coaxiality error.
There are two rows of symmetrical spherical rollers, the outer ring has a common spherical raceway, and the inner ring has two raceways inclined at an angle to the bearing axis. It has good alignment performance. When the shaft is bent or installed out of center The bearing can still be used normally at the same time. The alignment varies with the bearing size series. Generally, the allowable alignment angle is 1~2.5 degrees. This type of bearing has a large load capacity, and the bearing can withstand radial load. The double-acting axial load has better impact resistance. Generally speaking, the allowable working speed of spherical roller bearings is lower.

Spherical roller bearings are divided into two different structures: symmetrical spherical rollers and asymmetrical spherical rollers according to the cross-sectional shape of the rollers. Asymmetrical spherical roller bearings are early products, mainly for maintenance services for the main engine, and the new design of the main engine Symmetrical spherical roller bearings are rarely used. The internal structure has undergone a comprehensive improvement design and parameter optimization. Compared with the earlier produced spherical roller bearings, it can withstand greater axial load. The operating temperature of this bearing It is lower, so it can meet the requirements of higher speed. According to the inner ring with or without ribs and the cage used, it can be divided into two types: C type and CA type. C type bearings are characterized by no inner ring ribs and steel plate Stamping cage, CA type Teruien bearing is characterized by ribs on both sides of the inner ring and the use of car-made solid cage.
Spherical roller bearings are divided into: cylindrical bore and conical bore. The taper of the tapered bore is 1:12, the rear code is K for spherical roller bearings, and the 1:30, the rear code is for spherical roller bearings K30. When this type of bearing is matched with a conical shaft, the inner ring moves along the axial direction to adjust the radial clearance of the bearing.

Features:
1. The roller and raceway are in line contact or repaired offline contact, with large radial bearing capacity, suitable for bearing heavy loads and impact loads.
2. The friction coefficient is small, suitable for high speed, and the limit speed is close to the deep groove ball bearing.
3. The N type and NU type can move axially, can adapt to the change of the relative position of the shaft and the housing caused by thermal expansion or installation error, and can be used as a free end support.
4. The processing requirements for the shaft or the seat hole are high, and the relative deviation of the outer ring axis after the bearing is installed must be strictly controlled to avoid contact stress concentration.
5. The inner ring or outer ring can be separated for easy installation and disassembly.

What is the difference between ball bearings and roller bearings
1. Different in nature
1. Roller bearing: one of the widely used parts in modern machinery.
2. Ball bearing: A type of rolling bearing. The ball is installed in the middle of the inner ring and the outer ring and can bear a large load.
Two, the principle is different
1. Ball bearing: Determine the relative position of the two components (usually the shaft and the bearing seat) to ensure that they rotate freely while transmitting the load. At high speeds (such as in gyro ball bearings), this application can be extended to include free rotation, while the bearing has almost no wear.
2. Roller bearings: support rotating parts by rolling contact. Different rolling bearings can withstand different radial and axial forces. When selecting rolling bearings, they should be selected according to specific working conditions.

Needle roller bearings are equipped with thin and long rollers (roller diameter D≤5mm, L/D≥2.5, L is the roller length), so the radial structure is compact, and its inner diameter and load capacity are the same as other types of bearings , The outer diameter is the smallest, which is especially suitable for the bearing results where the radial installation size is limited. According to different applications, bearings without inner ring or needle roller and cage components can be selected. At this time, the journal surface and shell hole surface matching the bearing directly serve as the inner and outer rolling surfaces of the bearing to ensure load capacity and running performance Same as the bearing with ring, the hardness, machining accuracy and surface quality of the raceway surface of the shaft or housing hole should be similar to the raceway of the bearing ring. This kind of bearing can only bear radial load.