Spindle bearing

Spindle bearings

Single row angular contact ball spindle bearings can only withstand axial loads in one direction, which will cause additional axial forces when subjected to radial loads. And can only limit the axial displacement of the shaft or shell in one direction. The contact angle of the bearing is 40 degrees, so it can withstand a large axial load. The spindle bearing is a non separable design, with uneven shoulder heights on both sides of the inner and outer rings. In order to improve the load capacity of the bearing, one side of the shoulder will be machined lower, allowing the bearing to accommodate more steel balls.

The main shaft bearing can withstand large radial and axial combined loads and torque loads, limiting the axial displacement of the shaft in both directions. The tilting ability between the inner and outer rings of the double row angular contact ball bearing, which is mainly used to limit the bidirectional axial displacement of the shaft and shell, is limited. The allowable tilting angle depends on the internal clearance of the bearing, bearing size, internal design, and the forces and moments acting on the bearing. The maximum allowable tilting angle should ensure that there is no excessive additional stress generated in the bearing. If there is a tilt angle between the inner and outer rings of the bearing, it will affect the service life of the bearing, and at the same time cause a decrease in the operating accuracy of the bearing and an increase in operating noise. Double row angular contact ball bearings generally use nylon cages or brass solid cages. When installing double row angular contact ball bearings, attention should be paid. Although the bearing can withstand bidirectional axial loads, if there is a ball gap on one side, attention should be paid not to let the main axial load pass through the groove edge on the side with the gap. When using bearings, attention should be paid to ensuring that the raceway on the side without the ball groove bears the main load.

Paired double ball bearings

If installed in pairs, make the outer rings of a pair of bearings face each other, that is, the wide end face faces the wide end face and the narrow end face faces the narrow end face. This can avoid causing additional axial forces and limit the shaft or casing within the axial clearance range in both directions.

Due to the relative displacement of the inner and outer raceways on the horizontal axis, they can withstand both radial and axial loads - combined loads (single row angular contact ball bearings can only withstand unidirectional axial loads, so they are usually installed in pairs).

The materials of the cage include brass, synthetic resin, etc., which are distinguished according to the bearing form and usage conditions.

Many angular contact ball bearings are manufactured by German bearing manufacturers, and are commonly used in imported equipment in China, such as angular contact ball bearings 3204RS, etc,

The narrow edge is on the outside, the wide edge is on the inside, and the other wide edge is on the inside. The narrow edge is on the outside, which means back to back contact.

characteristic

1. Universal matching bearings

Universal assembly bearings are specially processed so that when the bearings are installed close to each other, any combination can achieve a predetermined internal clearance or preload, as well as an average load distribution, without the need for gaskets or similar devices.

Paired bearings are used when the load carrying capacity of a single bearing is insufficient (using a crossover configuration), or when it needs to withstand a combined load or axial load acting in two directions (using a back-to-back or face-to-face configuration).

2. Basic designed bearings (cannot be used for universal assembly), configuration for individual bearings

The basic design of single row angular contact ball bearings is mainly used in configurations with only one bearing at each position. Its width and protrusion are ordinary level tolerances. Therefore, it is not suitable to install two single row angular contact ball bearings tightly together.

Accuracy level

The accuracy level of angular contact ball bearings includes dimensional tolerances and rotational accuracy. The accuracy from low to high is represented as P0 (normal), P6 (P6X), P5, P4, P2. In addition, P3, P7, and P9 are also used in European and American brands to represent accuracy levels. P3 is equivalent to P6 level in ISO and JIS standards, P7 is equivalent to P4 level, and P9 is equivalent to P2 level.

There are several types of angular contact ball bearings: 7000C type (Å=15 °), 7000AC type (Å=25 °), and 7000B type (Å=40 °). The locking port of this type of bearing is on the outer ring, and generally the inner and outer rings cannot be separated. It can withstand combined radial and axial loads as well as axial loads in one direction. The ability to withstand axial loads is determined by the contact angle, and the larger the contact angle, the higher the ability to withstand axial loads. This type of bearing can limit the axial displacement of the shaft or casing in one direction.

The contact ball bearing has a high limit speed and can withstand both radial and axial loads, as well as pure axial loads. Its axial load capacity is determined by the contact angle and increases with the increase of the contact angle.

Single row angular contact ball bearing

Single row angular contact ball bearings can only withstand axial loads in one direction. When subjected to radial loads, additional axial forces are generated, and corresponding reverse loads must be applied. Therefore, this type of bearing is generally used in pairs. Double row angular contact ball bearings can withstand large radial and axial combined loads and torque loads, mainly radial loads. They can limit the bi-directional axial displacement of the shaft or shell, with a contact angle of 30 degrees.

Bearing code: 7

Paired installation of angular contact ball bearings

Paired installation of angular contact ball bearings can withstand radial and axial combined loads mainly based on radial loads, as well as pure radial loads. The series configuration can only withstand axial loads in a single direction, while the other two configurations can withstand axial loads in either direction. This type of bearing is usually selected by the manufacturer to be paired and submitted to the user. After installation, there is a pre press interference, and the ring and steel ball are in an axial pre load state, thereby improving the stiffness and rotational accuracy of the entire set of bearings as a single support.

Back-to-back configuration, with a post code of DB (such as 70000/DB), separates the load lines of bearings paired back-to-back from the bearing shaft. It can withstand axial loads acting in two directions, but the load in each direction can only be borne by one bearing. Back-to-back installed bearings provide a relatively rigid bearing configuration and can withstand overturning torque.

Face to face configuration, with the post code DF (such as 70000/DF), where the load lines of bearings paired face to face converge towards the bearing shaft. It can withstand axial loads acting in two directions, but the load in each direction can only be borne by one bearing. This configuration is not as rigid as back-to-back pairing and is not very suitable for withstanding overturning moments. The rigidity and ability to withstand overturning torque of this configuration are not as good as the DB configuration, and the bearings can withstand bidirectional axial loads;

In series configuration, with the code DT (such as 70000/DT), the load lines are parallel and the radial and axial loads are evenly distributed by the bearings. However, the bearing group can only withstand axial loads acting in one direction. If the axial load acts in the opposite direction, or if there is a composite load, it is necessary to add a third bearing adjusted by a relatively series paired bearing. This configuration can also connect three or more bearings in series at the same support, but can only withstand axial loads in a single direction. Usually, in order to balance and limit the axial displacement of the shaft, a bearing capable of bearing axial loads in the other direction needs to be installed at the other support.

Bearing code: 0

Load capacity (simple)

The following content only applies to the load capacity of paired bearings, and the basic rated load and fatigue limit load given in the product table are only applicable to individual bearings.

*Basic rated dynamic load, used for standard bearings in any configuration and SKF Explorer bearings in back-to-back or face-to-face configurations

C=1, 62xC single bearing

*Basic rated dynamic load,

C=2xC single bearing

*Basic rated static load

Co=2xCo single bearing

*Fatigue ultimate load

Pu=2xPu single bearing

Types of structural deformation

The characteristic of double row angular contact ball bearings is that they can simultaneously withstand a combined load of radial and axial loads, limiting the axial displacement of both sides of the shaft. Compared with bidirectional thrust ball bearings, this type of bearing has a higher limit speed, a contact angle of 32 degrees, good rigidity, and can withstand large overturning moments. It is widely used in front wheel hubs of small cars (some models also use double row tapered roller bearings of the same size).

There are four types of structural deformations in double row angular contact ball bearings:

Type A: Standard design for bearings with an outer diameter less than or equal to 90mm. There is no ball loading gap, so it can withstand equal bi-directional axial loads. Using lightweight fiberglass reinforced nylon 66 cage, the bearing temperature rise is very small.

Type A: Standard design for bearings with an outer diameter greater than 90mm. There is a ball loading gap on one side, equipped with Z-steel plate stamped cage or brass solid cage.

E-type: It is a reinforced structure with a ball gap on one side, which can accommodate more steel balls, thus having a higher load-bearing capacity.

Both A-type and E-type double row angular contact ball bearings with dust covers and sealing rings on both sides can be equipped with dust covers (non-contact) or sealing rings (contact) on both sides. The interior of sealed bearings is filled with anti rust lithium based lubricating grease, and the operating temperature is generally between -30 ° C and 110 ° C. No further lubrication is required during use, and no heating is required before installation.

When installing double row angular contact ball bearings, attention should be paid. Although the bearing can withstand bidirectional axial loads, if there is a ball gap on one side, attention should be paid not to let the main axial load pass through the groove edge on the side with the gap.