What Are Our Concerns About Bearings（35）

Q1: How many kinds of bearings?

I. According to the size of rolling bearing, it is divided into:  

• (1) miniature bearings —- nominal outer diameter size range of bearings below 26mm;  
• (2) small bearing —- nominal outer diameter size range of 28-55mm bearing;  
• (3) small and medium-sized bearings —- nominal outer diameter size range of 60-115mm bearings;  
• (4) medium and large bearings —- bearing with nominal outer diameter size range of 120-190mm  
• (5) large bearing —- nominal outer diameter size range of 200-430mm bearing;  
• (6) Super large bearing —- nominal outer diameter size range of 440-2000mm bearing.  
• (7) Heavy large bearings —- bearing with nominal outer diameter size range of more than 2000mm.  

Two, according to the direction of the load it can bear can be divided into: ① radial bearing, also known as centripetal bearing, bearing radial load.  ② Thrust bearing, also known as thrust bearing, bears axial load.  Radial thrust bearing, also known as centripetal thrust bearing, bears radial load and axial load at the same time.  According to the different friction properties of bearings, they can be divided into sliding friction bearings (referred to as sliding bearings) and rolling friction bearings (referred to as rolling bearings).  

Iii. Rolling bearings can be divided into:  

1. Deep groove ball bearings  

Deep groove ball bearing is a kind of bearing with simple structure, convenient use, large production volume and wide application range.  It is mainly used to bear radial load, but also can bear a certain axial load.  When the radial clearance of the bearing increases, it has the function of angular contact bearing and can bear larger axial load.  

2. Self-aligning ball bearings  

The self-aligning ball bearing has two rows of steel balls and two raceways in the inner ring. The raceways in the outer ring are inner spherical shape and have the performance of automatic self-aligning.  It can automatically compensate coaxiality error caused by shaft winding and shell deformation, and is suitable for supporting seat holes that cannot guarantee strict coaxiality of parts.  The bearing mainly bears radial load, while bearing radial load, it can also bear a small amount of axial load, usually not used to bear pure axial load, such as bearing pure axial load, only a row of steel balls.  

3. Angular contact ball bearings  

Angular contact ball bearings have high ultimate speed, and can bear both meridian and axial loads, as well as pure axial loads. Their axial load capacity is determined by the contact Angle, and increases with the increase of the contact Angle.  

4. Cylindrical roller bearings  

Cylindrical roller bearings usually consist of two retaining edges of a bearing ring, cage.  The roller and the ring form a composite, can be separated from another bearing ring, belongs to the separable bearing.  This kind of bearing is easy to install and disassemble, especially when required.  The outer ring and the shaft. The shell are interference fit to show more advantages.  Such bearings are generally only used to withstand radial loads, only within.  Single row bearings with fenders on the outer rings can bear smaller steady axial loads or larger intermittent axial loads.  

5. Self-aligning roller bearings  

The self-aligning roller bearing sentence has two rows of rollers, which are mainly used to withstand radial loads, but also can withstand axial loads in any direction.  The bearing has high radial load capacity and is especially suitable for working under heavy load or vibration load, but cannot bear pure axial load.  Good self-aligning performance, can compensate the same bearing error.  

6. Tapered roller bearings  

Tapered roller bearings are mainly suitable for bearing radial and axial combined load based on radial load, and large cone Angle tapered roller bearings can be used to bear radial and axial combined load based on axial load.  This kind of bearing is a separated bearing, the inner ring (including tapered roller and cage) and the outer ring can be installed separately.  In the process of installation and use, the radial and axial clearance of bearings can be adjusted, and pre-interference installation can also be used.  

7. Thrust ball bearing  

Thrust ball bearing is a separation type bearing. The “seat ring” of the shaft ring can be separated from the assembly of the steel ball of the cage.  The shaft ring is a ring matched with the shaft, the seat ring is a ring matched with the bearing seat hole, and there is a gap between the shaft.  

Thrust ball bearings can only pull the hand axial load, one-way thrust ball bearings can only bear the axial load of one room, two-way thrust ball bearings can bear the axial load of two directions.  The thrust ball can not limit the warp movement of the shaft, and the limit speed is very low.  One-way thrust ball bearings can limit the axial displacement of the shaft and the housing in one direction, and two-way bearings can limit the axial displacement of the two directions.  

8. Thrust roller bearing  

Thrust self-aligning roller bearings are used for bearing axial loads.  Combined longitudinal load, but the longitudinal load shall not exceed 55% of the axial load.  Compared with other thrust roller bearings, this kind of bearing has lower friction coefficient, higher speed and self-aligning ability.  The roller of type 29000 bearing is asymmetrical spherical roller, which can reduce the relative sliding of rod and raceway in operation, and the roller length.  Large diameter, large number of rollers, large load capacity, usually using oil lubrication, individual low speed can be used grease lubrication.  In the design and selection, should be given priority.  

9. Needle roller bearings  

Needle roller bearings are equipped with thin and long rollers (roller length is 3 to 10 times of diameter, diameter is generally not more than 5mm), so the radial structure is compact, its inner diameter size and load capacity and other types of bearings at the same time, small outer diameter, especially suitable for radial installation size limited support structure.  Bearing or needle roller and cage assembly without inner ring can be selected according to different use occasions. At this time, the journal surface and shell hole surface matching with the bearing are directly used as the inner of the bearing.  External rolling surface, in order to maintain the same load capacity and running performance as the bearing with rings, shaft or housing hole raceway surface hardness.  The machining accuracy and surface and surface quality should be similar to the raceway of the bearing ring.  This kind of bearing can bear radial load only.  

10. Outer spherical ball bearing with seat  

An outer spherical ball bearing with a seat consists of an outer spherical ball bearing with a seal on both sides and a cast (or steel plate stamped) bearing seat.  The inner structure of the outer spherical ball bearing is the same as that of the deep groove ball bearing, but the inner ring of the bearing is wider than the outer ring.  The outer ring has a truncated spherical outer surface, which can be automatically aligning with the concave spherical surface of the bearing seat.  Usually there is a gap between the inner hole of this bearing and the shaft. The inner ring of the bearing is fixed on the shaft with a top wire, an eccentric sleeve or a fixed sleeve, and rotates with the shaft.  Bearing with seat compact structure, easy loading and unloading, perfect sealing, suitable for simple support, often used in mining.  Metallurgy. Agriculture. Chemical industry.  Textile. Printing and dyeing. Conveying machinery, etc.