Spherical roller bearings introduction
Spherical roller bearings have double-row rollers, the outer ring has a common spherical raceway, and the inner ring has two raceways that are inclined at an angle relative to the bearing axis. This clever structure makes it have self-aligning performance, so it is not easy to be affected by the angle of the shaft and the bearing box seat on the error or shaft bending. It is suitable for installation errors or shaft deflection caused by angle errors. In addition to the radial load, the bearing can also withstand the axial load acting in both directions.
Spherical roller bearings have cylindrical and conical bores. The taper of the conical bore is 1:30 and 1:12. This conical bore bearing is equipped with an adapter sleeve or a withdrawal sleeve. The tapered inner hole self-aligning ball bearing can be easily and quickly assembled on the optical shaft or the stepper shaft.
The models of spherical roller bearings are spherical roller bearings (20000CC type); tapered bore spherical roller bearings (20000CCK type); spherical roller bearings (20000CC/W33 type); tapered bore spherical roller bearings (20000CCK/W33 type); Spherical roller bearings installed on the adapter sleeve (20000CCK+H type); Spherical roller bearings installed on the adapter sleeve (20000CCK/W33+H type) total 6 types.
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 it has good centering performance and can compensate for 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 axis of the bearing. It has good self-aligning performance. When the shaft is bent or installed out of center When the bearing can still be used normally, the alignment varies with the bearing size series. Generally, the allowable alignment angle is 1 to 2.5 degrees. This type of bearing has a large load capacity, and the bearing can withstand the 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 of 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 improved design and parameter optimization. Compared with the earlier produced spherical roller bearings, it can withstand a greater axial load. The operating temperature of this bearing It is low, 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. The characteristics of C type bearings are that the inner ring has no ribs and the use of steel plates. Stamping cage, CA type Teruien bearing is characterized by ribs on both sides of the inner ring and the use of a car-made solid cage. In order to improve the lubrication of the bearing, a spherical roller bearing with an annular oil groove and three oil holes on the outer ring can be provided to the user, which is indicated by the bearing postcode /W33. According to user requirements, spherical roller bearings with inner ring oil holes can also be supplied. In order to facilitate customers to install and replace bearings, spherical roller bearings with a taper inner hole can also be provided, and the taper hole taper is 1:12, The suffix code is K to indicate that in order to meet the requirements of special users, bearings with an inner bore taper of 1:30 can also be provided, and the suffix code is K30. Bearings with a tapered inner hole can be directly mounted on the tapered journal with a lock nut or can be mounted on the cylindrical journal with the aid of an adapter sleeve or a withdrawal sleeve.
structure type
Spherical roller bearings are divided into a cylindrical bore and a conical bore.
The taper of the tapered inner bore is 1:12, the rear-mounted spherical roller bearing code is K (type 153000 or 113000), and the 1:30 rear-mounted spherical roller bearing code is 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.
Postcode
After installing the tapered hole spherical roller bearings with the rear codes K and K30 on the matching adapter sleeves, they will become the rear codes K+H and K30+H bearings. This kind of bearing can be installed on an optical shaft without a shaft shoulder and is suitable for occasions where the bearing needs to be frequently installed and removed. In order to improve the lubrication performance of the bearing, there is an annular oil groove in the outer ring of the bearing and three evenly distributed oil holes are drilled, and the rear code is W33.
use
Mainly applicable cage: stamped steel reinforced cage (suffix E, few in China). Stamped steel plate cage (suffix CC), glass fiber reinforced polyamide 66 cages (suffix TVPB), machined brass two-piece cage (suffix MB). Machined brass integral cage (suffix CA), a stamped steel cage for vibration occasions (suffix JPA). Brass cage (suffix EMA) for vibration occasions. The same structure may have different codes on the bearings.
Main applications: papermaking machinery, reduction gears, railway vehicle axles, rolling mill gearbox bearing seats, rolling mill rolls, crushers, vibrating screens, printing machinery, woodworking machinery, various industrial reducers, vertical self-aligning bearings.
installation
Spherical roller bearings are equipped with drum-shaped roller bearings between the inner ring with two raceways and the outer ring with spherical raceways. The curvature center of the outer ring raceway surface is consistent with the bearing center, so it has the same centering function as the self-aligning ball bearing. When the shaft and housing are deflected, it can automatically adjust the load and the axial load in two directions. Large radial load capacity, suitable for heavy load and shock load. Bearings whose inner diameter is a tapered bore can be directly installed. Or use an adapter sleeve or a disassembly tube to install it on the cylindrical shaft. The cage uses steel stamping cage, polyamide forming cage, and copper alloy car cage.
For self-aligning bearings, when the bearing with shaft is installed into the box shaft hole, the use of an intermediate mounting ring can prevent the outer ring from tilting and rotating. It should be remembered that some sizes of self-aligning ball bearings have balls protruding from the side of the bearing, so the middle mounting ring should be recessed to prevent damage to the balls. A large number of bearings are generally installed by the mechanical or hydraulic press-in method.
For separable bearings, the inner ring and outer ring can be installed separately, which simplifies the installation process, especially when the inner and outer rings require interference fit. When installing the shaft with the inner ring in place into the bearing box that already contains the outer ring, care must be taken to check whether the inner and outer rings are correctly aligned to avoid scratching the bearing raceways and rolling parts. If cylindrical and needle roller bearings use inner rings without flanges or inner rings with flanges on one side, it is recommended to use mounting sleeves. The outer diameter of the sleeve should be equal to the inner ring raceway diameter F, and the tolerance standard for machining should be d10. Drawn cup needle roller bearings are best installed with mandrels.
Clearance
For the installation axial clearance of the spherical roller bearing, it can be adjusted by the adjusting nut on the journal, the adjusting washer, and the thread in the bearing seat hole, or the pre-tensioned spring. The size of the axial clearance is related to the arrangement of the bearing, 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 high-load and high-speed spherical roller bearings, when adjusting the clearance, the effect of temperature rise on the axial clearance must be considered, and the reduction in clearance caused by the temperature rise shall be estimated, that is, the axial clearance The gap should be appropriately adjusted to be larger. For low-speed and vibration-bearing bearings, clearance-free installation or preload installation should be adopted. Its purpose is to make the roller and raceway of the spherical roller bearing have good contact, the load is evenly distributed, and to prevent the roller and raceway from being damaged by vibration and impact. 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 body or the bearing seat, make the dial indicator contacts against the smooth surface of the shaft, push the shaft left and right along the axis, the maximum swing of the needle is the axial clearance value.
Pay attention to the problem
The pre-tightening force of spherical roller bearings is carried out at room temperature, but in working condition, the drive shaft and bearing pre-tightening force generated by the system's micro-stretching temperature rise will change. Therefore, the set pre-tightening force should be considered To this factor.
It needs the capacity, speed, and other conditions of the reasonable use of the preload of the spherical roller bearing to ensure the life of the transmission. If the pre-tightening force is too large, power consumption may even lead to overheating. If the pre-tightening force is too small, body load, shaft rolling, and the gap between the outer ring will produce beating, running, and transmission accuracy to reduce noise increase, affecting gear meshing, and severe damage to teeth and bearings.
According to the different spherical roller bearing assembly, such as the bearing pre-tightening nut which axially compresses the inner ring of the inner bearing directly rotates, the inner and outer rings, to eliminate the gap and realize the purpose of bearing pre-tightening force. Realization of common use: first, far beyond the pre-installed bearing, the nut at the end, and then back 1/4 turn. Assembling method, the advantages of this method are low investment, simplicity, practicality, and consistent quality of tapered roller bearings. It can be used.
1. Electric heating plate heating method. Put the bearing on the electric heating plate at a temperature of 100℃ for a few minutes. This method is the most convenient. For example, the bearing can be heated evenly by turning several times, and the efficiency is also high. Both large and small spherical roller bearings This method can be used.
2. Electric furnace heating method The bearing is heated in a closed automatic temperature control electric furnace, heating is uniform, temperature control is accurate, and heating is fast. It is suitable for heating many bearings in a batch.
3. The induction heating method uses induction heaters to quickly, reliably, and cleanly heat the spherical roller bearing to the required temperature. This is especially suitable for the occasions where the inner ring is tightly fitted, because only the inner ring is heated, and the outer ring The ring is less heated, so it can be easily installed on the shaft and easily installed in the seat hole.
4. The electric bulb heating method uses a 50W electric bulb to heat the spherical roller bearing, which can ensure that the heating temperature is about 100°C. The smaller bearing can be placed directly on the bulb, and the larger bearing can be placed in the conical cover of the bulb. The cover can prevent the heat loss of the bulb, and make the heating uniform. The cone cover can be adjusted up and down. It can be adapted to heating bearings of different sizes within a certain range. This kind of light bulb can be energy-saving bulb heating method is suitable for a small number and not often needed; occasions where the bearing needs to be heated, the light bulb can also be used for lighting, and no other equipment is required.
5.Oil tank heating method This is a widely used traditional heating method. A metal mesh is set at the bottom of the oil tank 50~70mm. The bearing is placed on the net. The large bearing should be lifted with a hook. The bearing should not be placed directly at the bottom of the groove to prevent contact with the groove. The bearing part at the bottom is locally heated too high, or the dirt deposited at the bottom of the groove enters the bearing oil groove. The points of attention are as follows. The non-corrosive mineral oil with good thermal stability should be used, preferably transformer oil. The oil and the container should be used. The capacity of the oil tank to keep clean should be determined by the size of the heated spherical roller bearing and the amount of oil. If the container is too small, the temperature of the oil in the bearing will drop quickly during continuous operation, and the effect will not be good.
Luoyang Yujie Industry &Trade Co.Ltd located in Luoyang City, one of the main heavy industrial bases in China. We specialize in the production of bearings, nonstandard machinery parts, machine tools. For the bearings, we can offer cross roller bearing, slewing bearing, YRT bearing, thin section bearing, ball screw bearing, deep groove ball bearing, etc. For the nonstandard machine parts, we can produce gears, shafts, sprockets, molds, rollers, pulley, mining machine parts, etc as per customer drawing and requirements. For the machine tools, we offer CNC vertical machine center, CNC horizontal lathe, CNC gantry boring and milling machine, CNC floor type boring, and milling machine.
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