Robotics and Automation

As the most common linear bearing type, rolling linear bearings provide the least friction by utilizing balls or rollers to create smooth motion. The rolling elements are located between the mating grooves in the bearing and guide rails. The roller’s or ball’s diameter is proportional to the linear speed of the linear guide, so as the diameter increases, the guide’s linear speed must also increase.

Similarly, the contact angle of the rolling element is directly proportional to the radial loading capacity, while the contact angle is inversely proportional to the lateral loading capacity. A 45° contact angle equally supports loads in lateral, radial, and reverse radial directions. There are several types of rolling linear bearings, and the three common classifications are according to:

1. Track Geometry: The linear bearing’s track geometry is the number of contact points the rolling elements make with the raceway, which determines the friction produced and the load capacity.
2. Geometry of Rolling Elements: The rolling elements of linear motion ball bearings can be spherical (such as steel balls), cylindrical, or cylindrical needles. The rolling element’s shape affects the load capacity and rigidity of the linear bearings.
3. Linear Guide Profile Shapes: The guide rails’ cross-sectional shape is the bearing’s linear guide profile and determines the linear bearing design required for the linear guide assembly.

Plain linear bearings consist of simple construction, often resulting in lower production costs than roller bearings. Instead of relying on rolling elements, plain linear bearings utilize the sliding contact of two surfaces. With the larger contact area, plain linear bearings reduce surface pressure, can handle larger loads, and are better at absorbing shocks and vibrations than other linear motion ball bearings. Lubrication or self-lubricating materials are essential for applications using plain linear bearings. Common types of plain linear bearings include:

• Dovetail Slides: Dovetail slides consist of a base with a protruding V-shaped tongue and mating saddle that create full contact with one another.
• Box-Way Slides: Box-way slides have a T-shaped profile when the mating base and saddle are together. The base is stationary, acting as the guide rail, while the saddle moves along the base.
• Fluid Linear Bearings: Fluid linear bearings use a thin layer of pressurized, fast-moving fluids such as hydrostatic or hydrodynamic fluid. Pumps or high-speed carriage motion is essential to pressurize the fluid.
• Linear Sleeve Bearings: Also known as plain linear bushings, linear sleeve bearings are hollow cylinders where the shaft guide rail slides along the inner surface, which is typically self-lubricating.
• Magnetic Linear Bearings: As the name implies, magnetic linear bearings use magnetic force to lift the carriage from the guide rail.

Our SW type linear motion bearings come in various styles for single-direction motion applications, all with internal seals (UU). These bearings are available in numerous materials, including chrome and stainless steel, with a resin or steel retainer. The side block housings also come in several styles.

Also known as the “Super Series,” our lightweight TW type linear motion bearings are low-noise bearings available in both standard and open styles. They have floating integral wiper seals for self-alignment and an advanced polymer resin cage. TW type linear motion bearings come in various materials and shaft shapes, making them ideal for single-direction motion applications. They have a higher load capacity and travel life than the SW series.

Our SM metric type linear motion bearings measure in millimeters and are most commonly used in Asia. SM metric type linear motion bearings are available in chrome or stainless steel with a resin or steel retainer. They feature internal seals (UU) and can be either adjustable or open. The slide block housings for these bearings are available in various styles.

Our KB metric type linear motion bearings are widely used in Europe for single-direction motion applications. KB metric type linear motion bearings come in a variety of shaft shapes with stainless steel or chrome material options and a steel or resin retainer. These bearings have internal seals (UU) and several slide block housing options.