Understanding the Different Types of Linear Bearings and Their Benefits

Are you looking for a linear bearing but don’t know where to begin?

To answer this question, it’s necessary to understand the different types of linear bearings and their benefits. Once you get yourself acquainted with this information, it becomes easy to pick one.

Generally, linear bearings are roller bearings that are used to transport a load while sliding up and down a shaft. It achieves smooth and precise linear motion with low friction.

In this article, we’ll discuss in detail the distinctive types of linear bearings.

So, let’s get started.

What is Linear Bearing?

Simply put, these are bearings that are featured with a roller system that provides movements only in a linear motion. By reducing the friction, it provides smooth and accurate motion along linear (straight) pathways. The durability of this device depends on the load and the required speed.

Linear bearings are used in many automated applications, including electronic equipment, packaging machinery, medical and laboratory equipment, measurement devices, CNC machinery and much more. The overall aim of linear bearing is to provide smooth and low-friction sliding in a straight motion.

Types of Linear Bearing

1. Linear Bush

A Linear Bush is a linear motion system used in conjunction with a cylindrical shaft to provide unrestricted linear motion. It consists of steel balls that run along a raceway, held by a retainer cage. This retainer cage is usually made of either plastic or metal. The recirculation of steel balls in this raceway track facilitates unlimited stroke with minimal frictional resistance.

It also consists of an outer sleeve or housing with two grooves on each end for circlips. The circlips enable these linear bearings to snap onto a housing that carries the load. The ends of each linear bearing are usually fitted with rubber seals to prevent dust from entering the raceway and interfering with the movement of the bearing.

Linear bushings are often named as “LM bush”. Apart from the material, there are also different lengths of the linear bush. The standard linear bush comes in a normal length and a longer “L” type length. For instance, a linear bearing with ID 10mm will have LM10UU and LM10LUU.

Finally, there are also three major types of linear bushings that are applicable to all sizes. They are the closed type (no suffix), the adjustable type (AJ) and the open type (OP). The adjustable and open types accommodate axial expansion and better fitting on the linear shaft, which are suitable for high temperature or high-speed applications.

2. Pressed Steel Linear Bush

This Pressed Steel linear bushing is also a suitable option for most of the linear motion applications. It is lighter and more compact than an LM bush. This makes it more suitable for applications with space constraints. It also comes with a steel outer housing, plastic cage, and two retaining ring grooves on both ends.

3. Flanged Linear Bush

Flanged linear bushings or bearings are usually distinguished according to the specific design and shape. Similarly, there are normal and longer types of flanged linear bushings available. It is divided into a few categories:

A round flange, with four mounting holes, connected to the outer housing. It is commonly known as LMF.

A square flange, with four mounting holes, connected to the outer housing. It is commonly named as LMK.

A flat undercut oval flange, with four mounting holes, connected to the outer housing. It is commonly referred to as LMH.

There are also different positions of the flanges. A flange on a linear bearing can be located in the middle, near to one end with slight protrusion of housing, or most commonly at the end of the bearing.

4. Stroke Bearings (ST)

Stroke bearings are linear bearings that have high accuracy and stiffness(rigidity). Most distinctly, it is limited by a specific stroke length. It has a higher load capacity as compared to a standard linear bearing. This bearing is generally used in heavy-duty applications. Stroke bearings can attain higher acceleration with low frictional resistance. These are suitable for precise and higher load applications.

5. Linear Slides (SC)

The linear slide units are extremely compact and lightweight due to the aluminium body. With the availability of various types, these linear slide units are equipped with various features like ease of mounting, stability, and cost-effectiveness. These are available in different designs and sizes that have abundant performances, depending on the item you select for the application.

6. Support Rail Unit (SBR/TBR)

The support rail unit is similar to the linear slides but they have higher load capacities. And they are able to accommodate for axial expansion. These top-of-the-line units provide maximum stiffness and rigidity to the shaft during the whole stroke. This complete sliding unit system can be clamped simply by bolts, making it easy to use.

Benefits of Linear Bearings

Here are the following advantages of linear bearings. Let’s have a look:

1. Long Service Life with High Accuracy

With reduced friction and noise, linear bearings have a long lifespan with high movement accuracy over an unlimited stroke.

2. High load Capacity

Due to the stability of linear bearings components, it can withstand loads both horizontally and vertically.

3. Ease of Installation and Low Maintenance

Installing a linear bearing is easy. Simply slide the bearing onto the shaft and secure the shaft with shaft holders. With low friction, minimal maintenance is needed throughout the lifespan of a typical linear bearing application.

4. Ease of Lubrication

In traditional sliding systems, insufficient lubrication leads to wear on the contact surfaces. It can also be difficult to ensure adequate lubrication of the contact surfaces due to the difficulty of finding an appropriate grease injection point. In a linear bearing, both oil and grease can be applied.

Grease is a better option for lubrication as it adheres more easily to metal surfaces. But oil is better used in high-speed applications where more heat is produced. Lubricants can be applied easily on the shaft which will be transferred to the recirculating system in the linear bearing.

5. Interchangeability

With standard specifications, linear bearings are easily interchangeable across brands.

Wrapping Up!

As you can see, linear bearings are fuss-free, reliable and durable. If you need assistance in choosing the right linear bearing, you can reach out to one of the leading linear bearing specialists - Shafttech.