Linear Guide Bearings Engineered To Give The Highest Quality
The Best Shaft Bearing for Your Application
In 1983, PBC Linear® created the self-lubricating Simplicity plain linear bearing – a technology that solves problems in dirt, vibration, shock loading, cleanrooms, welding, foundry, and washdown situations where linear ball bearings regularly fail. Today, PBC Linear provides a full range of linear motion solutions with the addition of our classic line of linear ball bearings for applications requiring continuous high-speed linear motion. Our complete portfolio of both plain bearing and ball bearings gives engineers the versatility to choose the right bearing for their application.
Plain Linear Bearings vs. Linear Ball Bearings
Both plain bearings and ball bearings have advantages and disadvantages. Use the chart below to help guide your decision-making process. If you require more assistance, be sure to contact your local representative for more guidance on the linear motion bearing selection process.
| Bearing Type | Max Static Load (Horizontal) | Max Speed | Coefficient of Friction | Precision | Environment | Temperature |
| Plain Bearing | 100,500 lbs (447,046 N) | 300 SFM (1.52 m/sec) With Lubrication: 825 SFM (4.19 m/sec) | 0.125 | Consistent over life and in a variety of environments Running clearance = 0.0005″ (0.0127 mm) per side | Excels in contaminated, wet, dry, and clean room applications | -240°C / +240°C |
| Ball Bearing | 2,165 lbs (9,630 N) | 590 SFM (3 m/s) Always requires lubrication | Average = 0.05 | Can change dramatically dependent on environmental conditions Can be preloaded, virtually eliminating play | Best suited for general manufacturing applications | -15°C / +80°C |
Design Considerations for Plain Bearings
2:1 Bearing Ratio for Plain Linear Bearings
The 2:1 Bearing Ratio is officially defined as the maximum ratio of moment arm distance to bearing length which will not cause binding or prevent motion. The Binding Ratio is often displayed numerically as “2:1,” where “2” is the moment arm distance and “1” is bearing length. For example, if 2x equals 10 inches then 1x must equal 5 inches. This rule applies to all plain bearings with cantilevered loads.
Plain Linear Bearings’ Maximum PV
The maximum pressure velocity (max PV) value should also be considered when designing applications with plain bearings. Plain bearings are graded according to their maximum PV value, determined by the load per unit area and velocity. Another word for a bearings’ max PV is its maximum dynamic capability.
To be deemed fit for application without lubrication, plain bearings must satisfy three specific criteria:
Calculate Pressure
- P = Maximum pressure or load in pounds per square inch (psi) or kilograms per square centimeter (kg/cm2)
- A = Projected Contact Area
- L = Bearing Length
- d = Shaft diameter
- W = Maximum load
Calculate Velocity
- V = Maximum velocity or surface speed in square feet per minute (sfm) or meters per minute (m/min)
- N = Rotational velocity
Calculate Maximum PV
PV = The performance measurement of plain bearings
Linear Motion Bearing Technology Provides Endless Possibilities
The superior technology behind PBC Linear plain bearings and ball bearings is applied to all products in our bearing portfolio. If a round bearing is not what you need, PBC Linear has other bearing styles that may be better suited for your application.
Leverage High Quality Bearing Assemblies
Our use of Simplicity plain bearing and ball bearing technology doesn’t just stop with bearings. PBC Linear utilizes bearings in our Simplicity Linear Slides.
The Perfect Pair: PBC Linear Shafts & Bearings
PBC Linear shafting is meticulously designed to perfectly complement high-performance linear motion bearing technology, ensuring prolonged lifespan, minimal maintenance, and dependable linear motion. Regardless of whether you’re using plain bearings or ball bearings, PBC Linear offers the best shafts suited for the job. Available in three standard materials—Carbon Steel, 400 Series Stainless Steel, and Ceramic Coated Aluminum—these shafts cater to a diverse array of applications. Shafting options are offered as either bar stock or pre-drilled, available in standard lengths or customizable cut-to-length configurations, with the option for tailored machined ends.