Linear bearings are precision-bored mechanical components with sliding or rolling elements along the bore that enable low-friction, straight-line motion while supporting and guiding loads along round shafts or round-profiled rails. Open-shell variants provide clearance for rail support.
Sliding-element bearings handle extreme temperatures, dirt, vibration, and contamination with less maintenance than rolling-element ball bearings because they eliminate balls that can jam, seize, brinell, or fail under harsh conditions. Rolling-element bearings are better suited for higher speeds and offset or cantilevered loads where plain bearings may bind due to the 2:1 rule, which requires bearing spacing to be at least twice the load overhang. PBC Linear offers sliding plain linear bearings, rolling linear ball bearings, and cam roller pillow blocks.
The flagship Simplicity® products are sliding plain linear bearings with FrelonGOLD® PTFE-based liners bonded directly to the bore. They provide self-lubricating, maintenance-free motion without metal-on-metal contact in harsh environments involving heat, cold, dirt, welding splatter, vibration, shock, contamination, and washdowns, as well as critical applications where bearing-replacement downtime is costly.
As a cost-saving polymer-lined alternative, injection-molded EconoGlide® plain bearings are also available. Plain linear bearings support linear, rotational, and oscillating motion. Simplicity® configurations include standard cylindrical, twin, flanged, die set, pillow block, and sleeve bearings for round shafts, as well as square bearings for square shafts.
Linear ball bearings use recirculating steel balls to travel axially along round shafts. They are better suited than plain linear bearings for higher speeds and cantilevered loads because of their lower coefficient of friction and the 2:1 binding rule that can limit plain bearing systems. They feature heat-treated alloy steel shells, polymer resin retainers, and standard double seals, with standard, twin, flanged, thin-wall, and pillow block configurations available.
Cam roller pillow blocks use open-shell aluminum housings with one or more sets of three opposing coated steel cam rollers that travel along rail-supported round shafts for long linear travel.
Linear bearings tend to be standardized around inch, ISO metric, and JIS metric shaft sizes.
PBC Linear Specifications for Simplicity Plain Linear Bearings:
- Self-Lubricating Bearing Liner is Bonded to the Bore ID: FrelonGOLD® is standard;
- Optional liners: Frelon®J for corrosive chemical conditions; Frelon®W (FDA compliant)
- Temperature Rating: -400°F/+400°F or -240°C/204°C
- ID Sizes: Available from 3/16” to 4” Inch Series, 5mm to 80mm Metric Series
- Maximum Horizontal Static Load: 2,165-100,500 lb (982- 45,586 kg)l
- Maximum Speed: Up to 8 m/s (315 in/s)
- Shaft Lengths: Up to 12 feet
- Shell Material: Standard is aluminum; stainless steel shells are available
- Self-Lubricating: Provides oil-free operation
- Seal Options: Nitrile rubber, urethane, and viton seals available from ½” ID and up or 20mm and up
- Mounting Options: O-ring and retaining ring grooves for multiple mounting options
- External Lubrication: Optional feature for added lubrication
- Vibration Damping: Ensures smooth and quiet operation
Specifications for EconoGlide Plain Linear Bearings:
- Injection Molded Polymer Bearing ID Liner
- Temperature Rating: -58ºF/+194ºF (-50ºC/+90ºC)
- ID Sizes: 3/8” to 2” and 8mm to 50mm
- Maximum Speed: 1.5 m/s
- Shell Material: standard is aluminum; stainless steel shells are available
- Self-Lubricating: Provides oil-free operation
- Mounting Options: O-ring and retaining ring grooves for multiple mounting options
- External Lubrication: Optional feature for added lubrication
- Vibration Damping: Ensures smooth and quiet operation
- Bearings available in inch and metric sizes; Flanged bearings are in metric sizes
Specifications for Linear Ball Bearings:
- Temperature Range: -4/+176°F (-20/+80°C)
- ID Sizes: Available from 1/4" to 2” Inch Series, and 8mm to 50mm Metric Series
- Static Load Capacities: Up to 1700 lb (7900 N)
- Dynamic Load Capacities: Up to 850 lb (3800 N)
- Interchangeable: Size interchangeable with industry standards and the Simplicity plain linear bearing series
- Low Coefficient of Friction: Ensures smooth operation
- Heat Treated Alloy Steel Shell: Provides durability
- Resin Retainer: Reduces noise
- Double Seals: Included as standard at no additional cost
Specifications for Roller Bearing Pillow Blocks:
- Use a floating "F" part number for each opposing block on parallel shafts to accommodate imperfect alignments.
- A set of opposing roller bearings consists of 1 fixed side roller, 1 eccentric side roller (to account for any misalignment) and a top support roller
- FUBK Series replacement kits include one new roller for each of the three in a set
- Order two replacement kits to cover more than one set of opposing bearings
Frequently Asked Questions
What is the difference between plain linear bearings and linear ball bearings?
Plain linear bearings use self-lubricating liners and are ideal for harsh environments, while linear ball bearings use recirculating steel balls for low friction and higher-speed performance.
What are the benefits of plain linear bearings?
Plain linear bearings provide maintenance-free, self-lubricating operation and perform well in environments with heat, dirt, debris, and vibration.
What are the advantages of linear ball bearings?
Linear ball bearings deliver high-speed, low-friction performance and eliminate the 2:1 binding limitation of plain bearings in cantilevered applications.
What does it mean for a linear ball bearing to brinell?
A linear ball bearing is said to brinell when its hardened steel balls create permanent dents in the bearing raceways due to excessive loads, impacts, or vibration. These dents can cause rough motion, increased noise, and reduced bearing life.
Which linear bearing is best for dirty or harsh environments?
Plain linear bearings are best suited for dirty or harsh environments because their self-lubricating liners resist contamination from dust, debris, and moisture.
Which linear bearing is best for high-speed applications?
Linear ball bearings are ideal for high-speed applications due to their low coefficient of friction and recirculating ball design.
When should cam roller pillow blocks be used?
Cam roller pillow blocks are ideal for heavy-load, long-travel applications, using coated steel cam rollers in open housing designs for durable performance along rail-supported round shafts.
Do linear ball bearings require lubrication?
Yes, most linear ball bearings require lubrication for optimal performance and service life, unlike self-lubricating plain bearings.
What motions do plain linear bearings support?
Round shaft plain bearings support rotary, linear, and oscillating motion, while square shaft versions support linear and oscillating motion only.
Are linear bearings interchangeable with industry standards?
Yes, most linear bearings are dimensionally interchangeable with industry-standard sizes.
What sizes are available for linear bearings?
Linear bearings match standard shaft sizes and are available in inch, metric, and JIS sizing.
What is the difference between plain linear bearings and linear ball bearings?
What are the benefits of plain linear bearings?
What are the advantages of linear ball bearings?
What does it mean for a linear ball bearing to brinell?
Which linear bearing is best for dirty or harsh environments?
Which linear bearing is best for high-speed applications?
When should cam roller pillow blocks be used?
Do linear ball bearings require lubrication?
What motions do plain linear bearings support?
Are linear bearings interchangeable with industry standards?
What sizes are available for linear bearings?
Types of Linear Bearings: Linear Plain Bearings, Linear Plain Bearing Flange Mounts, Linear Plain Sleeve Bearings, Linear Plain Pillow Block Bearings, Linear Plain Bearing Flange Die Set Bushings, Linear Plain Square Bearings, Linear Ball Bearings, Linear Ball Bearing Flange Mounts, Linear Ball Bearing Pillow Blocks, Roller Pillow Block Bearings, Single Roller Pillow Block Bearings, Double Roller Pillow Block Bearings, Twin Roller Pillow Block Bearings
Suggested Reading:
Features of Linear Bearings
Case Study - Woodworking Application
Case Study - Automotive Robots
Case Study - Weld Splatter Pushed Aside
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