High Precision Bearings | Characteristics for a Successful Set-Up

In electric motors, CNC machine tools and spindles, and actuators, bearings facilitate smooth motion, high RPMs, and axial and radial load control. As technology advances, the need for highly accurate and precise bearings increases so state-of-the-art machinery can run at peak levels.

Emerson Bearing provides high precision ball and roller bearings for these and other applications. Learn more about high precision bearings and considerations for setting up a bearing system.

High Precision Bearing Features

High precision bearings are made from stainless steel, ceramic, and chrome steel for hardness, low friction, and durability. Accurate, precise manufacturing means these bearings meet dimensional tolerances with minimal deviation across batches.

Characteristics include:

Examples include:

Angular Contact Ball Bearings

Inner and outer raceway tracks are offset in the axial direction. The cage sits at an angle of 15°, 20°, or 25° depending on axial loading. These bearings work for axial, radial, or combined load applications. They are often paired in sets that are mounted differently depending on requirements.

Radial Ball Bearings (i.e., Deep Groove Bearings)

These consist of lubricated ball bearings held between two raceways that align them. They work with radial, axial, and bi-directional axial loads.

Cylindrical Roller Bearings

Instead of spheres, cylindrical roller bearings use solid cylinders as rolling elements. They can be configured with single or multiple rows of bearings, which improve radial loading capacity.

Ball Screw Support Bearings

Ball bearings are contained in a housing that fits onto the screw to support it. The balls fit into the groove on the screw and travel back and forth to facilitate smooth movement. They are usually positioned at a steep contact angle, approximately 60°, and are available in single- and double-row configurations.

Setting Up High Precision Ball Bearings

Consider these factors when selecting bearings:

Mounting Matching Pairs

Bearings are used singly, in pairs, or in sets, mounted in these ways:

• Back-to-back: Lines of action diverge toward the bearing axis, for a larger space between the bearing center and loading point. They can accommodate axial loads in both directions, with one bearing for each direction.
• Face-to-face: Lines of action converge toward the bearing axis. Like back-to-back mountings, the bearings each accommodate one direction of axial load.
• Tandem mounting: Lines of action are parallel to each other. They can be used for single-direction axial or radial loads and can accommodate large axial loads.

Cages

Cages maintain ball or roller spacing and reduce friction. Not all bearing applications require cages. Heavier loads may not use cages to fit more balls for better weight bearing. This is referred to as a full complement of ball bearings. Foregoing a cage may result in more friction and wear on the balls over time.

Cages are available in many configurations for different operating conditions and speeds, including crown, pocket, and two-part cages. Common cage materials include:

• Phenolic cages: Often for high-speed applications, these are made from linen or paper impregnated with resin for a lightweight and strong cage.
• Machine bronze cages: These cages are ideal for applications with heavy loads or the potential for shock loading with moderate speed.

Materials and Temperatures

Chrome-steel is common for bearings; however, ceramic and stainless steel may also be used. Chrome-steel is heat-treated for strength and hardness.

All bearings have maximum operating temperatures, such as:

• Chrome-steel: 300° F
• Stainless steel: 570° F
• Ceramic: 750 to 2700° F depending on the material

Contact Angle

Contact angle influences the rotational speed and loading capacity in these ways:

• Lower contact angles: High-speed applications and light axial loads
• Higher contact angles: Axial rigidity and/or high axial loads

Preload

Preloading adds axial loading to the bearing prior to use. Bearings can be manufactured to automatically preload when installed, called a factory preload, or they can be externally preloaded on installation with the addition of a washer or spring. Preloading accomplishes several things:

• Prevents deformation from overloading
• Improves spin-to-roll ratio
• Improves load-bearing capacity
• Reduces friction and vibration
• Reduces contact angle differences at high speeds between the inner and outer rings

Preload Levels

In a factory preload, clearances between bearings and inner and outer raceways are adjusted. The force generated by preloading activates when the bearing is installed on the shaft. There are generally three levels of preload:

• Light (Suffix L)
• Medium (Suffix M)
• Heavy (Suffix H)

Emerson Bearing — High Precision Bearing Supplier

All bearings Emerson carries are manufactured to tight tolerances with high precision. Our high precision bearings are available in a variety of configurations and ABEC classes for diverse applications.

Check out our online product selector tool, or contact us or request a quote today to learn more.