About Linear Bearings and Linear Bearing Manufacturers
Including: Linear Air Bearings, Linear Ball Bearings, Linear Motion Bearings, Linear Roller Bearings, Linear Rotary Bearings, Metric Linear Bearings, Miniature Linear Bearings, Needle Bearings, Pillow Block Linear Bearings, Plastic Linear Bearings, Precision Linear Bearings & Slide Bearings.
Linear bearings are often used when an object is moved along a straight line with high precision in an industrial or manufacturing setting. The object being moved on the linear bearings generally only needs to be moved in one direction, which makes the function and design of these linear bearings simple. The movement is produced with a high amount of repetition and fluidity. They provide a sliding or rolling contact between the object being moved and the bearing, creating relative motion among parts of the machine. There are many common uses for linear motion bearings. They can be found in drawer glides and work station height adjustment mounts. Occasionally these are referred to as linear guides, but mostly they are used as part of an industrial motion control system, along with devices such as linear actuators. Other more general uses for various types of linear bearings include optic alignment, disk certification, precision dispensing, vision inspection, wafer testing and handling, precision gauging and automated production equipment. They are often made of materials such as bronze, plastic and stainless steel. In the United States, they are measured via the American measurement system, but in Europe, metric linear bearings are used. The three main types of linear bearings are linear ball bearings, linear roller bearings, including needle bearings, and slide bearings. Other types include precision linear bearings, miniature linear bearings, linear rotary bearings and linear air bearings. There are different options for linear bearing housings, including pillow block linear bearings. Linear bearings have become much more popular in recent years, largely due to industry advancements in robotic automation.
Linear ball bearings use a rolling element such as a hard round ball to separate 2 moving parts along a straight line that provides smooth, low friction linear motion in rotary applications. There are two types-radial ball bearings, which carry both radial and axial loads, while thrust ball bearings are solely designed for pure thrust loads. They are used for light to moderate loads. Linear roller bearings carry loads by placing round elements, usually cylinders, between two objects. They have more load capacity because the contact between the rollers and line spread the load out. They are self cleaning, inexpensive and simple to use. Needle bearings, a type of roller bearing, have cylinder rollers that are much smaller in diameter and use a thinly shaped needle roller. Slide bearings use low friction metals like Teflon and graphite inside of metal backing plates for linear movement and weight bearing. They are used on heated pipelines on oil production modules, in steel fabrication, and in oil or water transportation.
Air bearings are crossed roller slide assemblies that are controlled by a pair of air cylinders. They are low friction because the materials being moved ride on a cushion of air. They are round or rectangular, come with or without a vacuum and magnetic prload, and are used often in the aerospace industry and machine tools. Linear air cylinders are often made of aluminum and are used for tensile testing and precision positioning. Linear rotary bearings are used when accurate linear movement of large objects is required. They use a cylinder roller that is able to divide and handle heavy loads and are self-lubricating. They are used in car axels, machine shafts, clock parts and grinding machines. Precision bearings are used in machine-tool spindles and in other high-precision applications. They are considered high in quality and have a tight bearing tolerance. Miniature bearings operate at low torque and provide high performance in applications where low noise, minimal run-out and long life are required. Pillow block bearings are housings that are mounted to provide load support for a rotating shaft. They are often made of iron and may be plain, which constrain, guide or minimize friction in rotary or linear applications, or ball, which produce smooth, low friction movement in rotary applications.
Linear bearings use bushings, balls, slides, rails and grease and vary in size and strength. Manufacturers produce many different types of linear bearings used in conjunction with larger automated systems, such as positioning tables and robotic assisted assembly lines. One of these types, linear ball slides, is compact and has a small form factor and a short stroke. These slides have the ability to stroke up to one-third of the slide length. Crossed roller bearings, on the other hand, have a much larger load capacity than ball slides because of the contact line between each roller and the raceway. Linear bearings are easy to install and are typically low cost. Because there are so many linear bearing manufacturers, standardization is not common. Special consideration should then be made to determine what a bearing's width, length, inside diameter and load capacity needs to be for the specific application. Some of the linear bearings styles are self-cleaning and lubricating, while others need to be cleaned and lubricated with regularity to ensure successful utility.
Types of Linear Bearings
-
have a helical inner race that converts torque to thrust as the screw
and nut turn and the component moves in a linear direction.
-
are one of three primary types of linear bearings. They have more load
capacity than ball slides because of the contact line between each roller
and the raceway.
-
are a linear bearing design in which the balls are trapped in a frame
that spaces them at equal distances.
-
are similar to a crossed roller bearing, but the axes to all the other
rollers are parallel instead of crossed.
-
are curved to mimic the arc of a pendulum.
- use spherical parts to separate moving parts along a straight line.
- ,
often referred to as "linear
slides," are compact forms of linear bearings with small form
factor and a similarly short stroke. Maximum stroke can be about one-third
of the slide length, but the form factor justifies the stroke.
- are used to bear loads and direct linear motion.
- are ball bearings used to separate parts.
- are comprised of two basic components: a precision
linear slide (ball or cross roller), which serves as a linear bearing
and guide, and a drive mechanism, which accurately moves and positions
the slide top along the linear axis.
- are used when accurate linear movement of a large object
is required. These devices consist of a cylinder with circulating balls,
which is attached to a shaft and is able to slide up and down the shaft
and rotate around the shaft itself at the same time.
- use metal plates to resist friction.
Linear Bearings Terms
- The amount of play or movement displayed when a bearing's
inner ring is moved axially in relation to the outer ring.
- The load
under which a bearing can operate while rotating.
- A device
used to measure a bearing's performance, and for fault analysis
after use.
- A device used
to separate the rolling elements of a bearing (also known as a retainer).
- The result of rolling
elements being forced onto inner or outer raceways, leaving indentations
in the raceway which lead to premature bearing failure.
- Responsible for supporting
and moving the load. Carriers are commonly attached to the linear slide
with a bearing system.
- A wedge-shaped piece of
metal or wood designed to hold structural parts in place and/or provide
a bearing surface.
- The deteriorization
of bearing housings in grey
cast iron products.
- A special design
feature of a cage/retainer that allows grease to accumulate and then slowly
be fed to the rolling elements.
- The maximum amount
of weight that a bearing can withstand.
- A substance is used to lubricate the moving surface of a bearing,
protect against corrosion, conduct and transfer heat and keep contaminants
from entering.
- A term that refers
to the "fuzzy" appearance of the load-bearing surface of a
bearing, which is caused by contamination.
- The portion of the
bearing in which the ball or other part slides. Raceways provide the track
of confined movement for the bearing mechanism itself.
- The space
between the rolling elements and the races in an unmounted bearing, designed
so that the bearing has the necessary net clearance to operate.
- A device to stop the
ingress of contamination and the escape of lubrication.
- The long fasteners
used to hold the retainers together when riveted retainers are used in
a maximum bearing capacity.
- The ratio
of a material's strength to its cross-section.
- The study of friction,
lubrication and wear on two moving surfaces in contact.
- A statistical
analysis tool that is used to study bearing life and calculate the probability
of failure.