Classification and Application of Bearings
sliding bearing
Sliding bearings do not distinguish between inner and outer rings or rolling elements, and are generally made of wear-resistant materials. Commonly used in low speed, heavy load, lubricating oil filling, and difficult to maintain mechanical rotating parts.
Joint bearing
The sliding contact surface of joint bearings is spherical, mainly suitable for swing motion, tilt motion, and rotational motion.
Rolling bearings
Rolling bearings are divided into radial bearings and thrust bearings based on the direction of load they can withstand or the nominal contact angle. Radial contact bearings are radial bearings with a nominal contact angle of 0, while radial contact bearings are radial bearings with a nominal contact angle greater than 0 to 45. Axial contact bearings are thrust bearings with a nominal contact angle of 90, and thrust angular contact bearings are thrust bearings with a nominal contact angle greater than 45 but less than 90.
According to the shape of the rolling element, it can be divided into ball bearings and roller bearings. Roller bearings are divided into cylindrical roller bearings, needle roller bearings, tapered roller bearings, and self-aligning roller bearings according to the type of roller.
According to whether it can be aligned during operation, it can be divided into aligning bearings - bearings with spherical raceways that can adapt to the angular deviation and movement between the axis lines of two raceways, and non aligning bearings (rigid bearings) - bearings that can resist the angular deviation of the axis lines between raceways.
According to the number of rows of rolling elements, they are divided into single row bearings, double row bearings, and multi row bearings.
It can be divided into separable bearings and non separable bearings based on whether its components (rings) can be separated.
According to its structural shape (such as whether there is a filling groove, whether there are inner and outer rings, the shape of the ferrule, the structure of the retaining edge, and even the presence or absence of a cage), it can be divided into various structural types.
According to its outer diameter size, it is divided into micro bearings (<26mm), small bearings (28-55mm), small and medium-sized bearings (60-115), large and medium-sized bearings (120-190mm), large bearings (200-430mm), and extra large bearings (>440mm).
According to the application field, it is divided into motor bearings, rolling mill bearings, main bearings, etc.
It is divided into ceramic bearings, plastic bearings, etc. by material.
Deep groove ball bearing
Deep groove ball bearings are the most representative rolling bearings. Compared with other types of bearings of the same size, this type of bearing has a small friction coefficient, high limit speed, simple structure, low manufacturing cost, high accuracy, no need for regular maintenance, and a wide range of sizes and forms, making it the most widely used type of bearing. It mainly bears radial loads and can also withstand certain axial loads. When it only bears radial load, the contact angle is zero.
After installing the deep groove ball bearing on the shaft, it can limit the axial displacement in both directions of the shaft or shell within the axial clearance range of the bearing, thus enabling axial positioning in both directions. When deep groove ball bearings have large radial clearance, they have the performance of angular contact bearings and can withstand large axial loads. Under high-speed operating conditions with high axial loads, deep groove ball bearings have more advantages than thrust ball bearings. In addition, this type of bearing also has a certain degree of centering ability. When tilted 2 'to 10' relative to the casing hole, it can still work normally, but it has a certain impact on the bearing life.
Angular contact ball bearing
Generally speaking, the six types of bearings represented by 36 and 46 bearings have angular contact values of 15 degrees, 25 degrees, 45 degrees, etc.
Self-aligning ball bearing
A self-aligning ball bearing is a bearing equipped with spherical balls between the inner ring of two raceways and the outer ring of a spherical raceway. The curvature center of the outer ring raceway surface is consistent with the center of the bearing, so it has the same centering function as automatic self-aligning ball bearings. When the shaft and casing are bent, they can be automatically adjusted without increasing the bearing burden. Self aligning roller bearings can withstand radial loads and axial loads in both directions. The self-aligning ball bearing has a large radial load capacity and is suitable for situations with heavy loads and impact loads. The inner diameter of the inner ring is a tapered hole bearing that can be directly installed. Alternatively, use a locking sleeve or disassembly cylinder to install it on the cylindrical shaft. The cage is formed using steel plate stamping and polyamide Self aligning ball bearings are suitable for bearing heavy and impact loads, precision instruments, low noise motors, automobiles, motorcycles, metallurgy, rolling mills, mines, petroleum, papermaking, cement, sugar squeezing and other industries, as well as general machinery.
Thrust ball bearing
Thrust ball bearings are divided into two types: unidirectional and bidirectional. They can only withstand axial loads and must not withstand any radial loads. The thrust bearing is divided into two parts: a tightening ring and a movable ring. The tightening ring is tightly connected to the shaft sleeve, and the movable ring is supported on the bearing seat. Ferrules and rolling elements are usually made of high-strength and wear-resistant rolling bearing steel, and the surface hardness after quenching should reach HRC60-65. Cages are often made of soft steel stamping, and can also be made of copper alloy cloth, adhesive wood, or plastic.
Bidirectional thrust angular contact ball bearing
The contact angle of thrust angle contact ball bearings is generally 60 °. The commonly used thrust angle contact ball bearings are bidirectional thrust angle contact ball bearings, mainly used for precision machine tool spindles. They are generally used in conjunction with double row cylindrical roller bearings and can withstand bidirectional axial loads. They have advantages such as high accuracy, good rigidity, low temperature rise, high speed, and easy assembly and disassembly.
Thrust roller bearing
This includes thrust cylindrical roller bearings, thrust tapered roller bearings, thrust needle roller bearings, and thrust self-aligning roller bearings.
Needle bearing
Needle roller bearings are equipped with thin and long rollers (the length of the rollers is 3-10 times the diameter, and the diameter is generally not greater than 5mm), so the radial structure is compact. Its inner diameter size and load capacity are the same as other types of bearings, and the outer diameter is the smallest. It is particularly suitable for supporting structures with limited radial installation size. Needle roller bearings can choose bearings without inner rings or needle and cage components according to different usage scenarios, At this point, the surface of the journal and shell hole that match the bearing are directly used as the inner and outer rolling surfaces of the bearing. To ensure the same load capacity and operating performance as the bearing with a ring, the hardness, machining accuracy, and surface quality of the surface of the shaft or shell hole raceway should be the same as that of the bearing ring The purpose combination needle roller bearing is a bearing unit composed of radial needle roller bearings and thrust bearing components. It has a compact structure, small volume, high rotational accuracy, and can withstand both high radial loads and certain axial loads. And the product structure is diverse, adaptable, and easy to install. Composite needle roller bearings are widely used in various mechanical equipment such as machine tools, metallurgical machinery, textile machinery, and printing machinery, and can make the mechanical system design very compact and agile.
Outer spherical ball bearing
The outer diameter surface of the outer ring of an outer spherical ball bearing is spherical, which can play a role in centering.
Spherical Roller Bearings
Self aligning roller bearings have two rows of symmetrical spherical rollers, which mainly withstand radial loads and can also withstand axial loads in any direction, but cannot withstand pure axial loads. The outer race of this type of bearing is spherical, so its centering performance is good, which can compensate for coaxiality errors. When the shaft is bent or installed unevenly, the bearing can still be used normally. The centering performance varies with the size series of the bearing, and the generally allowable centering angle is 1-2.5 degrees. This type of bearing has a large load capacity. In addition to being able to withstand radial loads, the bearing can also withstand bidirectional axial loads, and has good impact resistance, Generally speaking, the allowable working speed of self-aligning roller bearings is relatively low. Suitable for working under heavy or vibrating loads.
Flange bearing
The outer wheel of the flange bearing is equipped with a flange flange. The characteristic is that it can simplify the structure of the host, reduce the size of the host, and make the bearings easier to locate.
Bearing with seat
A component composed of a radial bearing and a seat, with a base plate for installing screws on a support surface parallel to the bearing axis.
Combination bearing
A rolling bearing composed of two or more bearing structures simultaneously within a set of bearings. For example, needle and thrust cylindrical roller combination bearings, needle and thrust ball combination bearings, needle and angular contact ball combination bearings, etc.
Linear bearing
Linear bearings are divided into metal linear bearings and plastic linear bearings.
Metal linear bearing is a kind of low-cost linear Motor system, which is used in combination with cylindrical shaft for unlimited travel. Due to the point contact between the bearing ball and the shaft, the load is small. The steel ball rotates with minimal frictional resistance, allowing for high-precision smooth motion.
The plastic linear bearing is a linear Motor system with self-lubricating characteristics. The biggest difference between the metal linear bearing and the metal linear bearing is that the metal linear bearing is a rolling friction, and there is a point contact between the bearing and the cylindrical shaft, so it is suitable for low load and high-speed motion; The plastic linear bearing is Sliding friction, and there is surface contact between the bearing and the cylindrical shaft, so it is suitable for high load, medium and low speed movement.