Linear bearings create relative motion among parts of a machine by providing a rolling or sliding contact between the bearing and the object that the bearing is moving. Linear motion bearings are used for a variety of functions. For example, they can be found in items such as work station height adjustment mounts, and drawer glides. Often times, linear bearings are used as part of industrial motion control systems, working alongside other devices such as linear actuators.
Linear bearings are often made from stainless steel, bronze, and plastic, and can be used for other applications such as automated production equipment, precision gauging, wafer testing and handling, vision inspection, precision dispensing, disk certification, and optical alignment. Linear bearings manufactured in the United States use the American measurement system. In Europe, on the other hand, manufacturers measure their linear bearings using the metric system.
There are three main types of linear bearings: linear ball bearings, linear roller bearings, needle bearings, and slide bearings. There are other types such as linear air bearings, linear rotary bearings, miniature linear bearings, and precision linear bearings. There are options available for linear bearing housing, such as pillow block linear bearings. Due to advancements in robotic automation, linear bearings have increased in popularity. Read More…
Linear ball bearings utilize a rolling component, such as a hard round ball, to move two separate parts along a straight line, providing linear motion which is fluid and low-friction. Rotary applications commonly use linear ball bearings. There are two types of linear ball bearings available. The first, radial ball bearings, carry both axial and radial loads. The second, thrust ball bearings, are used solely for light to moderate thrust loads.
Linear roller bearings carry their loads by placing rounded (typically cylindrical) components between two parts. Linear roller bearings are capable of carrying greater capacities due to the contact between the roller and the line being more evenly distributed. Linear roller bearings are easy to use, inexpensive and self-cleaning. Needle bearings are a type of roller bearing that have a thinly-shaped needle roller, and have cylindrical rollers that are smaller in diameter compared to those of a linear roller bearing.
Slide bearings perform linear movement and weight bearing using low-friction metals such as graphite and Teflon, as opposed to metal backing plates. Slide bearings are commonly found on oil production modules and heated pipelines, and in oil and water transportation and steel fabrication applications.
Air bearings are assembled of crossed roller slides controlled by two air cylinders. Air bearings are low-friction due to the materials they move riding atop a cushion of air. Air bearings are commonly used for machine tools and can be found in many aerospace applications. They can be round or rectangular, and come with or without magnetic or vacuum components. Linear air cylinders are commonly made of aluminum, and are utilized for applications such as precision positioning and tensile testing.
Linear rotary bearings are used for applications that require linear and precise movement of large objects. Linear rotary bearings use a cylindrical roller that is self-lubricating and is capable of handling and dividing heavy loads. These bearings can be found in car axles, grinding machines, clock parts, and machine shafts. Precision bearings have a narrow bearing tolerance, and are high in quality. They are recommended for use in high-precision applications such as machine tool spindles. Miniature bearings
Linear bearings can vary in strength and size, and utilize bushings, grease, rails, balls, and slides. Many types of linear bearings are manufactured to work alongside larger automated systems such as robotic assisted assembly lines and positioning tables. One example, linear ball slides, has a short stroke, has a small form factor, and is compact. These characteristics give them the ability to stroke up to one-third of the length of the slide. Alternatively, crossed roller bearings, have a much higher load capacity due to the bearing’s contact line between the raceway and the roller.
Linear bearings are inexpensive and allow for easy installation. Due to the large number of linear bearing manufacturers, it is not common to standardize the configurations of linear bearings. Therefore, attributes such as the bearing’s load capacity, inside diameter, length, and width should be taken into consideration. There are some styles of linear bearings that are self-lubricating and self-cleaning, while other types must be lubricated and cleaned manually. Regardless, lubrication and cleaning are necessary procedures that need to be carried out regularly in order to ensure maximized longevity and performance.
Terms Associated with Linear Motion Bearings
Linear bearings are often referred to as linear slides and linear actuators. They are used for moving a load (applied to a component) in one direction with the help of a rail system. The load is put on the rail, which is flat and has a simple design. The rail has a casing in which there are channels or an assembly of balls. Sometimes, the rail design can be a rod to meet some specific load bearing purpose. Linear bearing mechanisms are durable and heavy-duty, but a great part of their accuracy and performance relies on the load, speed, and frequency at which they are being utilized.
Linear motion bearings that have rollers are commonly used for guiding, supporting, and moving machine parts and products in various industrial and automation applications. The job of these profiles is to provide smooth, accurate motion, and low friction for the movement of the associated component.
Linear bearings are a commonly used tool in furniture manufacturing. They can be seen in drawer systems. The moving part in your computer table, on which you place the keyboard, also has a linear bearing system.
The surface of the slide or bearing and the rail system need to be smooth to ensure silent and efficient operation.
This article underlines some of the most common terminologies, associated with linear motion bearings –
Linear Guides – These guides have rotating balls, also known as roller bearings. The ball or the roller is mounted with a rectangular pad. The pad is designed to carry the load safely. Linear guides can efficiently bear heavy loads, owing to their design advantages. Sometimes, linear guides can have more than one rail systems. Such bearings are used for fast and unfailing movement.
Balls Spline – For some linear slide designs, manufacturers often use the term “ball spline.” Ball spline is a type of linear bearing that has a cylinder that works as the roller or the sliding unit in the motion bearing mechanism. The cylinder is connected with at least three circuits that give it the movement or rotation. Sometimes, the number of circuits can be up to five. Ball splines can be programmed for tough duties; they are easy to operate.
Bushings – Bushings are the most basic type of linear motion bearings. They are a type of cylinder acting as the roller element of the system. The cylinder, which is an injection-molding product, is tightly connected with a thin wall. The cylinder is programmed to rotate around a polished rod. Sometimes, lubricants are used to achieve smooth and noise-free rotation.
V Rail – If the length of the railing system is longer than usual, then the railing system is often designed in a V shape. This strategy is followed to avoid confusions and complexities in the bearing mechanism. Due to the simple and intelligent design of V rail systems, there are less chances of damage. Dust and other particulates also stay away from the rail, because of the cover attached to its sides.