Linear Bearings

Linear bearings are mechanical components designed to provide smooth, low-friction motion along a straight path, enabling repeatable movement in linear motion systems. They are commonly used in machinery, automation equipment, and positioning systems where controlled travel along a single axis is required.

RS Singapore offers a wide range of linear bearings in various sizes, load ratings, and configurations to suit different mechanical and motion control applications.

How Linear Bearings Work

Linear bearings enable linear movement by reducing friction and maintaining motion along a fixed path.

• Guided Motion and Friction Reduction: Linear bearings support and guide a moving load along a shaft, rail, or guideway while minimising friction between moving and fixed components. By constraining motion to a defined path, they enable smooth, accurate, and repeatable linear travel.
• Rolling-Element Motion: In rolling-element designs, balls or rollers circulate within the bearing, creating rolling contact between surfaces. This significantly reduces friction and enables continuous, low-resistance motion for high-speed and precision applications.
• Sliding Motion (Plain Bearings): Plain linear bearings operate through direct sliding contact between the bearing and the shaft or guide surface. Although friction is higher than in rolling systems, they offer advantages such as improved load distribution, shock absorption, and tolerance to contamination.
• Load Support and Stability: Linear bearings support radial, axial, and moment loads, depending on the design, ensuring stable motion and alignment under varying operating conditions.
• Performance Requirements: Performance depends on the bearing, shaft or rail, housing, mounting surface, lubrication, and sealing. Proper alignment, lubrication, and protection from contaminants help maintain low friction and reliable operation.
• Wear and Reliability: Incorrect alignment, insufficient lubrication, contamination, or unsuitable load direction can increase friction, noise, and wear, reducing accuracy and service life. Correct selection and installation are therefore essential.

Types of Linear Motion Bearings

Linear bearings come in distinct designs, distinguished mainly by their rolling or sliding elements and by the rail or shaft they run along.

Profile Rail Guides

Profile, or square, rail guides use recirculating ball or roller carriages that run along a profiled steel rail. They deliver high stiffness, positioning accuracy, and load capacity per unit length, which makes them suitable for machine tools and precision automation, though they require a straight, well-prepared mounting surface and suitable sealing against debris.

Round Shaft Linear Bushings

Round shaft linear bushings, also called linear ball bushings, ride along hardened and ground round shafts. These bearings are modular, economical, and tolerant of slight shaft misalignment, and can be end-supported or fully supported depending on the load and span, but they generally offer lower stiffness and accuracy than profile rails of a comparable size.

Crossed Roller Bearings

Crossed roller bearings use cylindrical rollers arranged alternately at 90 degrees to one another in a crisscross pattern. This arrangement provides high rigidity, smooth movement, moment load capacity, and high motion accuracy, making these bearings well-suited to precision robotics, measuring instruments, semiconductor equipment, and high-resolution imaging platforms.

Plain Linear Bearings

Plain linear bearings create motion through direct sliding contact rather than rolling elements. Their simple construction makes them a cost-effective solution, while the large contact area can support loads and help absorb shocks and vibrations. To reduce friction, they may use engineered polymers, sliding liners, or self-lubricating materials such as PTFE-filled compounds. However, they generally offer lower positioning accuracy and repeatability than rolling-element bearings.

Contactless Bearings

Contactless, or air, bearings float the moving element on a thin film of pressurised gas, so the surfaces do not make mechanical contact during operation. The result is very low friction, minimal wear, and no stick-slip, making them suitable for metrology, semiconductor, and other ultra-precision positioning applications.

Linear Bearing Selection Guide

Select a linear bearing based on the application's load, accuracy, operating conditions, and maintenance requirements.

• Bearing Type: Choose the bearing type based on the application’s accuracy, load, and operating conditions. Profile rail guides suit high-precision, high-stiffness applications. Round shaft linear bushings offer a cost-effective solution for general automation and light-duty systems. Crossed roller bearings provide very high rigidity and moment load capacity for precision equipment. Plain linear bearings are ideal where low maintenance, quiet operation, or contamination resistance is prioritised.
• Precision and Accuracy Requirements: Applications requiring high positioning accuracy and repeatability typically require profile rail or crossed roller systems. Less demanding applications can often use round shafts or plain linear bearings.
• Misalignment Tolerance: Consider installation accuracy. Round shaft systems generally tolerate more misalignment and are easier to install, while profile rail systems require accurate mounting and alignment.
• Load Capacity and Rigidity: Evaluate the load direction and magnitude. Profile rail and crossed roller bearings provide higher rigidity and better support for moment loads, while round shaft and plain bearings suit lighter loads.
• Maintenance Requirements: Rolling-element bearings may require periodic lubrication and cleaning, while self-lubricating plain bearings reduce maintenance effort, particularly where regular servicing is difficult.
• Environmental Conditions: Dust, moisture, and chemical exposure should influence bearing selection. Plain bearings and sealed systems may perform better in harsh environments, while rolling systems require cleaner conditions to maintain accuracy and service life.
• Cost vs Performance Trade-Off: High-precision systems offer superior accuracy and stiffness but cost more and require more precise installation. Simpler bearing types may provide sufficient performance at a lower cost.

Applications for Linear Shaft Bearings

Linear bearings enable repeatable motion in automated systems, supporting tables, carriages, and tooling wherever controlled travel along an axis is required. Different bearing types and materials are available to meet varying load, speed, accuracy, and environmental requirements.

CNC Machine Tools & Metalworking

In CNC milling machines, lathes, grinders, and engraving machines, linear guides move the worktable or cutting tool along each axis. Their stiffness and low friction help maintain precision during cutting, positioning, and finishing operations.

Electronics Manufacturing

Linear bearings drive the pick-and-place and component-placement systems used to assemble circuit boards and devices, where repeatability is critical to accurate placement and inspection. Low-particle, self-lubricating, or well-sealed designs may be selected in cleanroom electronics and semiconductor assembly, where contamination must be minimised.

Food Processing

Food and washdown environments may require corrosion-resistant, sealed, or lubrication-free linear bearings, including stainless steel or suitable polymer designs. These help resist moisture and contaminants while maintaining reliable motion in hygiene-sensitive production areas.

Pharmaceutical Packaging

In packaging, linear bearings support the movement of machine parts used for filling, sealing, labelling, and capping containers as they pass along a conveyor. Smooth, repeatable travel helps maintain consistent operation and supports high-speed production.

Intelligent Warehouse Logistics

In automated storage and material handling, linear bearings support transfer units, palletising systems, and pick-and-place robots that move goods through the facility. They can also be used in a linear robot track, sometimes called a seventh axis, extending a robot's reach along a horizontal path without repositioning the base.

Trusted Linear Shaft Bearings Manufacturer & Supplier in Singapore

As a trusted supplier, distributor, and manufacturer in Singapore, RS offers linear bearings from established brands such as SNR, INA, Bosch Rexroth, and RS PRO at competitive prices.

You can order online by selecting the products you need, adding them to your basket, and choosing your preferred delivery option at checkout. Eligible Singapore stock items may qualify for next-working-day delivery, subject to availability and order cut-off times.

RS also offers a wider range of linear motion products, including linear rails, linear bearing units, linear shafts, and related bearing maintenance tools, to support installation and maintenance requirements.

To know more about delivery options, lead times, and charges, refer to our delivery page.