Product Description

An angular contact ball bearing uses axially asymmetric races. An axial load passes in a straight line through the bearing, whereas a radial load takes an oblique path that tends to want to separate the races axially. So the angle of contact on the inner race is the same as that on the outer race. Angular contact bearings better support "combined loads" (loading in both the radial and axial directions) and the contact angle of the bearing should be matched to the relative proportions of each. The larger the contact angle (typically in the range 10 to 45 degrees), the higher the axial load supported, but the lower the radial load. In high speed applications, such as turbines, jet engines, and dentistry equipment, the centrifugal forces generated by the balls changes the contact angle at the inner and outer race. Ceramics such as silicon nitride are now regularly used in such applications due to their low density (40% of steel). These materials significantly reduce centrifugal force and function well in high temperature environments. They also tend to wear in a similar way to bearing steel—rather than cracking or shattering like glass or porcelain.

Angular contact ball bearing have high limit rotational speed, they can carry radial load and axialload simultaneously, they cal also withstand purely radial load. The axial load carrying capacity dependson the magnitude of contact angle and increases with increasing contact angle.

Structures

1. Separable angular contact ball bearings

The inner ring and outer ring of this type of bearings cannot be separated and comprises following structures:

Contact angle *=15°, counter bore on outer ring, 7000C type

Contact angle *=25°, counter bore on outer ring, 7000ACtype

Contact angle *=40°, counter bore on outer ring, 7000B type

2. Four-point contact ball bearings

This type of bearings is separable bearings. Whereof, QJ000 type has two piece inner ring and QJF000 type has two piece outer ring. Their contact angles are same as 35°. When received no load or pure radial load, the steel balls of the ball bearing contact with the four points of the rings. Besides the steel balls perform a two point contact with the ring when it is received a pure axial load. In addition, besides the axial load from both directions, this kind of bearing can take torque-load as well.

3. Double row angular contact ball bearings

This kind of bearings can accommodate radial loads as well as axial loads acting in both directions; they can also take torque load. They can restrain the axial displacement from both directions of the shaft or housing; the contact angle is 30° (or 40°).

Cage material

Angular contact ball bearings generally adopt pressed steel cages or copper solid cages. Double-row angular contact ball bearings generally adopt copper solid cages.

Sealing solutions

  Bearings sealed on both sides are lubricated for the life of the bearing and should not be washed or relubricated. The bearings are considered virtually maintenance free. If they are to be hot mounted, an induction heater should be used.                                                we do not recommend heating capped bearings above 80 °C (175 °F). However, if higher temperatures are necessary make sure that the temperature does not exceed the permissible temperature of either the seal or grease, whichever is lowest. During start up, grease may leak at the inner ring. For bearing arrangements where this would be detrimental, special design steps must be undertaken. 

Non-contact seals

Bearings with non contact seals can be operated at the same speeds as open bearings. The seals form an extremely narrow gap with the inner ring shoulder (fig. 1). They are made of oil and wear resistant NBR that is reinforced by a sheet steel insert. The seals, which are fitted in a recess on the outer ring, make good, positive contact with the recess.

Single row angular contact ball bearings with a non contact seal on both sides are identified by the designation suffix 2RZ.

Greases for sealed bearings

Sealed single row angular contact ball bearings are filled as standard with the high performance polyurea grease (GXN). Its specifications are listed in table 1. The standard grease is not identified in the bearing designation (no designation suffix).

Permissible speed

The permissible speed can be estimated using the speed ratings listed in the product table and applying the information provided under Speeds. If no reference speed is listed in the product table, the limiting speed is the permissible speed.

Bearing pairs

For bearings arranged in pairs, the permissible speed calculated for a single bearing should be reduced to approximately 80% of the quoted value.

Design of bearing arrangements

Proper adjustment

Single row angular contact ball bearings must either be used with a second bearing (fig. 1) or in sets . The bearings must be adjusted against each other until the requisite clearance or preload is obtained (→ Bearing preload).

When universally matchable bearings are mounted immediately adjacent to each other, there is no need for adjustment (→ Bearings for universal matching). The requisite clearance or preload is obtained by choosing bearings from an appropriate clearance or preload class and by applying suitable fits for the bearings on the shaft and in the housing.

The performance and operational reliability of single bearings depend on proper adjustment while universally matchable bearings depend on the correct selection of clearance or preload. If there is too much clearance in the bearing arrangement during operation, the load carrying capacity of the bearings is not fully utilized. Excessive preload produces more friction and higher operating temperatures, leading to a reduction in bearing service life.

Axial loads in one direction

Back to back and face to face arrangements require special attention when the axial load acts predominantly in one direction. This creates unfavourable rolling conditions for the balls of the axially unloaded bearing and can lead to increased noise levels, discontinuity in the lubricant film and increased stresses on the cage. When the axial load acts predominantly in one direction, we recommends zero operating clearance, which can be attained by using springs.

Load ratio

Because of the 40° contact angle, favourable rolling conditions for bearings in the 70 B, 72 B(E) and 73 B(E) series require a load ratio of Fa/Fr ≥ 1. A load ratio of Fa/Fr < 1 can reduce bearing service life.

Features

1.High Quality Steel - Ultra clean steel to extend bearing life by up to 80%.

2.Advanced Grease Technology - lubricants that can extend grease life and performance.

3.High Grade Balls - Quiet and smooth operation even at high speed.

4.Super Finished Raceways - Specially honed to minimise noise and improve lubricant distribution and life.

5.Contact Angle - Offered in 15, 25, 30 and 40 degree angles.

6.Cages - Available in a range of Polyamide, steel and brass cage assemblies.

Angular Contact Ball Bearing Series

Many angular contact bearing manufacturers have three or more dimensional series to accommodate higher speeds or higher loads than “standard.” In particular, the most common series names are:

ISO 18                    Series - highest speed, lowest load bearings

ISO 19                    Series - second highest speed, with the second lowest load bearings

ISO 10                    Series - highest load, second lowest speed bearings

ISO 02                    Series - highest load, lowest speed bearings

ISO  Equivalents to DRZ's Series Designations

Many times, manufacturers have further separated the ISO dimensional classes by adding a higher speed variant with the same dimensions. The following table summarizes DRZ's product offerings:

ISO Series                                  DRZ Designation

ISO 18                                       718 Series Angular Contact Bearings

ISO 19                                       719 Series Angular Contact Bearings

ISO 19                                       (high speed)H719 Series Angular Contact Bearings

ISO 10                                       70 Series Angular Contact Bearings

ISO 10                                        (high speed)H70 Series Angular Contact Bearings

ISO 10                                        (high load)B70 Series Angular Contact Bearings

ISO 02                                         72 Series Angular Contact Bearings