There are many differences between Angular Contact Bearings and Radial, Deep Groove, Ball Bearings, as we wrote about in Differences Between Angular Contact & Deep Groove Bearings.
There are also small differences in the design of angular contact bearings that make a huge impact on capabilities and performance.
This article will go through the anatomy and characteristics that make Angular Contact Bearings special and unique.
The Design of Angular Contact Bearings
The outer raceway shoulder design of the angular contact bearing is the first noticeable difference. The increased contact angle allows the bearing to support higher loads (weight) and faster speeds.
The contact angle is measured by two intersecting lines, one that’s formed at the point of contact between the ball and the two raceways and the other line that’s formed from the perpendicular plane to the bearing axis. The most common angles are 15° and 25°.
The smaller the contact angle the faster the speed (rpm) of the bearing.
High Precision Bearing Material
The three components of a bearing are
- Bearing Rings (a.k.a. Bearing Races)
- Bearing Cage
- Bearing Balls
Bearing Ring Material
Our bearing rings are made with 52100 vacuum degassed chrome steel (100Cr6), commonly referred to as bearing steel. This material is heat stabilized for temperatures up to 302°F (150°C). On request, an additional heat treatment can be done for working temperatures up to 572°F (300°C).
If you have working temperatures from 572°F to 932°F (500°C), our suggested material for the rings changes to high temperature tool steel.
Bearing Cage Material
We use a standard TA cage for our angular contact bearings. The TA cage is made from phenolic resin with fine mesh cotton webbing. The permissible operating temperature is 248°F (120°C).
Ball Bearing Material
We stock bearings with two ball options:
- 52100 vacuum degassed chrome steel (100Cr6), commonly referred to as bearing steel
- Ceramic, Silicon Nitride (Si3N4) which can increase bearing life, operate at a faster speed and has lower heat conductivity
There are two different types of preload: Spring preload & Rigid preload.
Spring preload works well at high speeds and can withstand temperature changes in the machine part. In order to be effective, the spring has to be arranged in the same direction as the external axial load.
The example on the right shows a spindle where bearing 1 has a fixed location and bearing 2 has an outer ring that’s free to move axially.
The spring force acts on the outer ring of bearing 2 and results in a permanent preload of both bearings almost independent of speed and temperature factors. Be sure to use a slip fit tolerance on the housing that is around the bearing.
Bearings preloaded in this example can be used up to the max speed if oil lubrication is used.
Rigid preload works well at lower speeds lower speeds and has a distinct higher axial/radial rigidity than a spring preload.
The example on the right shows both bearings that are paired and mounted with a rigid preload in the axial direction. Bearings arranged like this have a defined rigid preload.
The change of the preload under operating conditions has to be considered to achieve a long bearing life. Some considerations to include: RPM, temperature, load and more.
Contact us to learn more about all the individual components that make up angular contact bearings.