Precision angular contact ball bearings

Accuracy Grades： Angular contact ball bearing accuracy grade includes dimensional tolerance and rotational accuracy. The accuracy is expressed from low to high as Angular contact ball bearings P0 (common), P6 (P6X), P5, P4, P2. In addition, European and American brands also use P3, P7, P9 to express the accuracy level, P3 is equivalent to ISO and JIS standard P6 level, P7 is equivalent to P4 level, P9 is equivalent to P2 level.

There are several types of angular contact ball bearings: 7000C type (∝=15°), 7000AC type (∝=25°) and 7000B (∝=40°). This kind of bearing lock mouth in the outer ring, generally the inner and outer ring can not be separated, can bear radial and axial combined load and a direction of the axial load. The ability to bear the axial load is determined by the contact angle, the larger the contact angle, the higher the ability to bear the axial load. This kind of bearing can limit the shaft or shell in a direction of axial displacement.

Contact ball bearing limit speed is high, can bear radial load and axial load at the same time, also can bear pure axial load, its axial load capacity is determined by the contact angle, and with the increase of contact angle and increase.

Single row angular contact ball bearing

Single row angular contact ball bearing can only withstand a direction of the axial load, in bearing radial load, will cause additional axial force, must be applied to the corresponding reverse load, therefore, this kind of bearing are generally used in pairs. Double row angular contact ball bearing can bear larger radial load mainly radial, axial two-way combined load and moment load, it can limit the shaft or shell two-way axial displacement, the contact angle is 30 degrees.

Bearing code: 7

Angular contact ball bearings have raceways on the inner and outer rings, and the inner and outer rings can be displaced along the axial direction of the bearing. This kind of bearing is especially suitable for bearing compound load, that is, radial and axial at the same time the role of the load. Angular contact ball bearing axial load bearing capacity with the increase in contact angle α and increase. Contact angle for the radial plane of the ball and raceway contact point line and bearing axis of the vertical line between the angle.

Angular contact ball bearing models are divided into: α = 15 ° angular contact ball bearing (70000C type); α = 25 ° angular contact ball bearing (70000AC type); α = 40 ° angular contact ball bearing (70000B type); back-to-back pairs of duplex angular contact ball bearing [70000C (AC, B)/DB type]; face-to-face pairs of duplex angular contact ball bearing [ 70000C(AC,B)/DF]; Tandem pairs of angular contact ball bearings [70000C (AC,B)/DT]; Double row angular contact ball bearings with ball gap (type 00000); Double row angular contact ball bearings without ball gap (type 00000A); Double row angular contact ball bearings without ball gap and with dust cover on one side (type 00000A-Z); No ball notch, both sides with dust cover double row angular contact ball bearings (00000A-2Z type); no ball notch, one side with a seal double row angular contact ball bearings (00000ARS type); no ball notch, both sides with a seal double row angular contact ball bearings (00000A-2RS type); four-point angular contact ball bearings (QJ0000 type), total 13 kinds.

Single row angular contact ball bearing can only bear axial load in one direction, when bearing radial load, it will cause additional axial force. And can only limit the axial displacement of the shaft or shell in one direction. Angular contact ball bearings have a contact angle of 40 degrees, so they can withstand a large axial load. Angular contact ball bearings are non-separate design, the shoulders on both sides of the inner and outer rings are different in height. In order to increase the load capacity of the bearing, the shoulder on one side is machined lower, thus allowing the bearing to fit more balls.

Double-row angular contact ball bearings can withstand larger radial load-based radial and axial combined load and moment load, limiting the axial displacement of both sides of the shaft. Mainly used to limit the shaft and shell two-way axial displacement of the components in the double row angular contact ball bearing between the inner and outer ring can be tilted limited, the allowable tilt angle depends on the internal clearance of the bearing, bearing size, internal design and the force and moment acting on the bearing, and the maximum allowable tilt angle should ensure that the bearing does not produce too high additional stress. If there is a tilting angle between the inner and outer ring of the bearing, it will affect the life of the bearing, and at the same time cause the bearing running accuracy to decrease and the running noise to increase. Double row angular contact ball bearings generally use nylon cage or brass solid cage. Double angular contact ball bearing installation should be noted, although the bearing can bear two-way axial load, but if there is a ball loading gap on one side, it should be careful not to let the main axial load through the notched side of the groove edge. In the use of bearings should be careful to make without the ball notch side of the raceway to bear the main load.

Single row angular contact ball bearing can only bear axial load in one direction, when bearing radial load, it will cause additional axial force. And can only limit the axial displacement of the shaft or shell in one direction. Angular contact ball bearings have a contact angle of 40 degrees, so they can withstand a large axial load. Angular contact ball bearings are non-separate design, the shoulders on both sides of the inner and outer rings are different in height. In order to increase the load capacity of the bearing, the shoulder on one side is machined lower, thus allowing the bearing to fit more balls.

Double-row angular contact ball bearings can withstand larger radial load-based radial and axial combined load and moment load, limiting the axial displacement of both sides of the shaft. Mainly used to limit the shaft and shell two-way axial displacement of the components in the double row angular contact ball bearing between the inner and outer ring can be tilted limited, the allowable tilt angle depends on the internal clearance of the bearing, bearing size, internal design and the force and moment acting on the bearing, and the maximum allowable tilt angle should ensure that the bearing does not produce too high additional stress. If there is a tilting angle between the inner and outer ring of the bearing, it will affect the life of the bearing, and at the same time cause the bearing running accuracy to decrease and the running noise to increase. Double row angular contact ball bearings generally use nylon cage or brass solid cage. Double angular contact ball bearing installation should be noted, although the bearing can bear two-way axial load, but if there is a ball loading gap on one side, it should be careful not to let the main axial load through the notched side of the groove edge. In the use of bearings should be careful to make without the ball notch side of the raceway to bear the main load.

In case of paired duplex mounting, the outer rings of the pair of bearings are opposite to each other, i.e. the wide end faces the wide end and the narrow end faces the narrow end. This can avoid causing additional axial force, and can make the shaft or housing in both directions to limit the axial clearance range.

Because of its inner and outer ring raceway can have relative displacement in the horizontal axis, so can simultaneously withstand radial load and axial load – combined load (single row angular contact ball bearing can only withstand single direction axial load, so generally are often used to install pairs).

The material of the cage has brass, synthetic resin, etc., according to the bearing form, use conditions and distinguish.

Angular contact ball bearings are more foreign bearing manufacturers, more domestic applications in imported equipment, such as angular contact ball bearings 3204RS, etc.

Narrow side out, wide side in, another wide side in, narrow side out, is back-to-back contact.

1、Universal mating bearings

Universal mating bearing is specially processed, when the bearings are mounted close to each other, any combination can achieve the established internal clearance or preload, as well as the average load distribution, without the use of shims or similar devices.

Paired bearings are used in: when the load carrying capacity of a single bearing is insufficient (using tampering configuration) or when the combined load or axial load acting in two directions (using back-to-back or face-to-face configuration) is to be borne.

2, the basic design of the bearing (can not be used as a universal group), for the configuration of a single bearing

The basic design of single row angular contact ball bearing is mainly applied in the configuration of only one bearing in each position. Its width and protrusion are common grade tolerances. Therefore it is not suitable for mounting two single-row angular contact ball bearings close together.

Double-row angular contact ball bearings are characterized by the ability to simultaneously withstand combined radial and axial loads, limiting the axial displacement of both sides of the shaft. Compared with two-way thrust ball bearings, this bearing limit speed is higher, the contact angle is 32 degrees, good rigidity, can withstand large tilting moment, widely used in the front wheel hub of small cars (some models also use the same size double-row tapered roller bearings).

There are four types of structural deformation of double-row angular contact ball bearings.

Type A: Standard design of bearings with outer diameter less than or equal to 90mm. No ball loading notch, so can bear equal two-way axial load. The use of lightweight glass fiber reinforced nylon 66 cage, bearing temperature rise is very small.

Type A: Standard design for bearings with an outside diameter greater than 90mm. One side has ball notch, equipped with steel plate stamping cage or brass solid cage.

Type E: reinforced structure with ball notch on one side for more balls, thus higher load capacity.

Both A type and E type double row angular contact ball bearings can have dust caps (non-contact) or seals (contact) on both sides. The sealed bearings are filled with rustproof lithium grease and operate at temperatures generally between -30 and 110 degrees Celsius. No re-lubrication is required during use, and they are no longer heated before mounting.

Double row angular contact ball bearings should be installed with care, although the bearing can withstand two-way axial load, but if there is a ball loading gap on one side, then care should be taken not to let the main axial load through the groove edge of the side with the gap.

Single-row angular contact ball bearings: machine tool spindles, high-frequency motors, gas turbines, centrifugal separators, small car front wheels, differential pinion shafts, booster pumps, drilling platforms, food machinery, indexing heads, welding machines, low-noise cooling towers, electromechanical equipment, coating equipment, machine tool slot plates, arc welding machines

Double-row angular contact ball bearings: oil pumps, Roots blowers, air compressors, various transmissions, fuel injection pumps, printing machinery, planetary reducers, extraction equipment, cycloidal reducers, food packaging machinery, welding machines, soldering irons, square boxes, gravity guns, wire strippers, half shafts, inspection and analysis equipment, fine chemical machinery

Angular contact ball bearing mounting tips

High-speed precision angular contact ball bearings are mainly used for high-speed rotating occasions with lighter loads, requiring high precision, high speed, low temperature rise, low vibration and a certain service life. It is often used as a support for high-speed electric spindles in pairs, and is a key component of high-speed electric spindles for internal surface grinding machines.

Mounting form

Angular contact ball bearings are available in back-to-back, face-to-face and tandem arrangements. Back-to-back (two bearings of the wide end face relative) installation, bearing contact angle line along the direction of the rotary axis diffusion, can increase its radial and axial support angle rigidity, anti-deformation capacity is the largest; face to face (two bearings of the narrow end face relative) installation, bearing contact angle line towards the rotary axis direction convergence, its support angle rigidity is smaller. As the inner ring of the bearing extends out of the outer ring, when the outer rings of the two bearings are pressed together, the original clearance of the outer ring is eliminated, which can increase the preload of the bearing; tandem arrangement (two bearings with wide end faces in one direction) when installed, the contact angle line of the bearing is the same and parallel, which can make the two bearings share the working load in the same direction. But when using this mounting form, in order to ensure the axial stability of the installation, two pairs of bearings in tandem arrangement must be installed opposite to each other at both ends of the shaft.

Main technical indicators.

1. bearing precision index: more than GB/307.1-94 P4 level precision

2. High speed performance index: dmN value 1.3~1.8x 106 /min

3. Service life (average): >1500 h

High-speed precision angular contact ball bearing service life has a great relationship with the installation, should pay attention to the following matters

1. the bearing installation should be carried out in a dust-free and clean room, the bearing should be carefully matched, the spacer for the bearing should be ground, and the parallelism of the spacer should be controlled below 1um under the premise of keeping the spacer of the inner and outer rings equal in height.

2. the bearings shall be cleaned before installation, cleaned with the inner ring slope facing upward, with flexible hand sensing and no stagnation, dried, and put into the specified amount of grease, such as oil mist lubrication shall be put into a small amount of oil mist oil

3. the bearings should be installed with special tools, with even force, and knocking is strictly prohibited

4. the bearings should be stored in a clean and ventilated place with no corrosive gas and relative humidity not exceeding 65%. long-term storage should be regularly anti-rust.

1、When the bearing runs to a certain period (or warranty maintenance period), the bearing will be removed completely.

2、Cleaning with diesel oil or kerosene soaking cleaning bearings, such as the best technical conditions to open the seal cover cleaning;.

3、After cleaning air dry cleaning oil, appearance check for damage.

4, with a 150mm or so, the diameter of the angular contact ball bearing inner diameter equal to the wooden rod (preferably hollow tube), one end fixed a bearing.

5, with the hand quickly turn the bearing at the same time, the other end of the stick (wooden tube) in the ear or audio amplifier microphone to listen to the bearing rotation noise.

6, fixed bearing after lateral paddle stick, check whether the bearing wear loose phenomenon.

7, loose serious, excessive rotational noise, serious defects of FAG bearings should be eliminated, with the same model instead.

8, take a bucket will be the appropriate amount of grease (high-quality yellow dry oil) with a civilian fire melted (not overheated), the tested bearings into the bucket soaked to no bubble overflow. Remove the bearing before the grease cools down, the amount of residual grease is small. Remove the angular contact ball bearing after the grease cools down, the amount of residual grease is more. Determine the amount of grease residue according to the need.

9、Wipe the grease outside the bearing with a soft cloth or toilet paper and assemble the FAG bearing to the pulley in its original state, the maintenance work is finished.