Wire-roller bearings are widely used in military equipment because they meet the following stringent requirements: quick and convenient installation and maintenance, compact structure, simple operation, and enhanced reliability. These bearings are commonly employed as slewing ring bearings in radar systems, where they can withstand heavy loads while occupying minimal space, fully satisfying operational needs.

Wire-rolled raceway bearings are widely used in textile machinery, particularly in circular knitting machines.

Complete and detailed explanation of the full series of Franke steel wire track (steel wire raceway) bearings in Germany
Franke (Franke GmbH, Allen, Germany) invented the core principle of a four wire steel wire raceway bearing in 1936: replacing the traditional integral bearing ring with four independently quenched steel wires, the ball contacts at four points, and the rolling elements only contact the steel wire raceway and do not directly contact the equipment body; It has five core advantages: ultra compact, lightweight, omnidirectional bearing, adjustable preload, and impact resistance. It is divided into five product lines: rotating steel wire raceway bearings (rotary type), thin integrated bearings, finished rotary bearing assemblies, cross roller steel wire bearings, and linear steel wire track guides. The following full series of classifications, structures, parameters, and applicable scenarios are fully explained.

Franke four wire steel wire principle profile

Structure of rotary bearing components

Linear steel wire guide profile
1、 Basic universal technology (universal across the entire series)
1. Core principles
Four point angular contact four wire steel wire raceway, bearing radial/axial/overturning moment in all directions; The steel wire is chromium silicon quenched hard steel, the rolling element bearing steel, and the cage is made of PA nylon/TPU polyurethane; The pre tension can be freely set, and the rotational damping can be adjusted.
2. General materials and working conditions
Rolling steel wire: quenched and tempered chromium silicon steel; Rolling element: GCr15 bearing steel; Holder: PA66/TPU
Temperature: -30 ℃~+80 ℃, short-term peak value of 100 ℃
Linear velocity: maximum 5m/s for ball bearing type (10m/s without seal); Cross roller maximum 2m/s
Lubrication: Recommended Kl ü ber Isoflex NCA52 low viscosity grease
3. General advantages
The installation space is extremely small, and the same load-bearing section is only one-third of that of traditional thin bearings; Weight reduced by 60%
Steel wire has elasticity, resistance to vibration and impact, and is not easily stuck
No integral ring, the equipment body can be made of lightweight materials such as aluminum, plastic, and stainless steel
Inner diameter 60mm~2000mm, full-size customizable, supports non-magnetic ceramic ball bearings, stainless steel anti-corrosion version
2、 Rotating steel wire raceway bearing components (bare bearings, customers need to process the inner and outer mounting seats themselves)
1. LEL Series | High precision ground circular steel wire ball bearings (flagship precision version)

LEL grinding raceway profile
Core structure
Circular cross-section, CNC precision ground steel wire raceway, raceway contour perfectly fits the ball, with a four point contact ball structure; Standard ball specifications are 1.5/2.5/4/5/7mm.
size range
Installation section height 5.9-20.9mm; inner diameter 70-2000mm; special customized steel wire thickness up to 20mm, ball bearing up to 50mm.
Core Features
Highest precision, extremely low friction, smooth operation, and minimal rotational runout
The pre tightening interval is wide, which can achieve high-precision positioning with zero gap
Excellent impact resistance and elastic cushioning
Applicable Industries
Medical CT/MRI equipment, semiconductor wafer equipment, optical lens turntable, industrial robot joints, precision indexing plates for detection
Standard sub model
LEL1.5, LEL2.5, LEL4, LEL5, LEL7 (number=ball diameter mm)
2. LER Series | Economic shaped rectangular steel wire ball bearing (universal standard version)

LER rectangular shaped raceway
Core structure
Rectangular shaped stamped steel wire raceway, no high-precision grinding required, lower cost; Four point ball contact, with a flatter cross-section than LEL.
size range
Ball bearings 2/3/4/5mm; inner diameter 80-1800mm; moderate installation thickness.
Core Features
High cost-effectiveness, easy installation, medium precision, preferred for batch universal use; Same omnidirectional carrying capacity.
Applicable Industries
Knitting circular knitting machine (Franke classic matching), automated dividing table, packaging machinery, AGV car rotation, lightweight robotic arm
Standard sub model
LER2、LER3、LER4、LER5
3. LEW series | Cross roller steel wire raceway bearing (high rigidity heavy-duty version)

LEW Cross Roller Physical
Core structure
Single row intersecting cylindrical rollers, arranged horizontally in a staggered manner; Grinding steel wire raceway, roller line contact, and overturning stiffness are much higher than ball bearing series.
size range
Roller 4/7mm; inner diameter 150-500mm, large heavy-duty models LEW7-0400, LEW7-0500.
Core Features
Extremely high radial/axial/moment stiffness, with the strongest anti overturning ability
Stable under impact and heavy load conditions, suitable for continuous tilting torque loads
The rotational speed is lower than that of the ball bearing series, with a maximum linear velocity of 2m/s
Applicable Industries
Heavy duty machine tool turntable, welding positioner, heavy-duty AGV, wind power small rotary, laser cutting rotating fixture
Standard sub model
LEW4, LEW7 (number=roller diameter mm)
4. LEG series | Double ring split steel wire bearing (customized with large diameter and large stroke)
Core structure
Two sets of independent steel wire raceway rings combined with double row four point ball structure, with a split design, suitable for ultra large diameter, large opening hollow equipment.
Core Features
Large hollow aperture, split assembly, can be disassembled and assembled on site; Double row lifting capacity, suitable for circular guide rails and large hollow turntables.
Applicable Industries
Large radar, large optical detection ring, hollow robot seventh axis, circular conveyor line
3、 Integrated thin bearing (LSA series, with built-in steel shell, no machining base)
LSA series Slim ultra-thin integrated steel wire bearing
Core structure
Inner and outer ring steel packaging+built-in special-shaped steel wire raceway+ball cage, complete thin bearing finished product, directly replacing traditional ultra-thin equal section bearings.
Dimensions
Ball 4/6/8mm, extremely thin cross-section, ultimate compression of installation space.
Core Features
Ready to use out of the box, no need for customer processing of raceway seats; Cost lower than split bearing components; Medium precision, lightweight.
Applicable Industries
Small camera gimbal, automated small turntable, instrument rotation mechanism, small packaging equipment
4、 Finished slewing bearing assembly (LV full series, with housing/seal/optional gear, complete slewing unit)
No customer processing required, complete rotary bearing, divided into six subcategories: steel shell, aluminum shell, single/double row, with external teeth/without teeth:
1. LVD/LVE | Rotary assembly with external teeth (integrated drive)
LVD: Steel shell+external teeth+steel wire ball bearings+double-sided sealing, heavy-duty drive
LVE: Aluminum alloy shell+external teeth, lightweight and low self weight, AGV、 Preferred for lightweight robots
2. LVA/LVB | toothless smooth surface rotary assembly (driven rotary)
LVA: Steel shell, high load-bearing and wear-resistant
LVB: Aluminum alloy shell, lightweight, low inertia
3. LVC | Double row steel high dynamic rotary assembly
Double row steel wire ball bearings, double load capacity, high acceleration and frequent start stop working conditions
4. LVG | Double row crossed roller aluminum rotary bearing
Cross roller+aluminum shell, high rigidity+lightweight, high torque load, dedicated for photovoltaic tracking bracket and heavy-duty automation positioner
General advantages of assembly
Double sided lip seal for dust and water resistance; Pre installed lubricating grease; Standard installation flange holes, direct bolt assembly; Optional positioning pin and brake disc installation position.
5、 Linear Steel Wire Track Guide System (Linear Motion Product Line, Franke Linear)
Extending the principle of four wire steel wire raceway to linear motion, aluminum guide rail+embedded quenched steel wire raceway, weighing only 50% of traditional steel guide rail, divided into two main structures: single track and double track:

Complete set of linear steel wire guide rail
1. Dual track linear system (standard module)
Composed of * * profile guide rail+ball slider (slide seat) * *, with 4 steel wire raceways built into the guide rail; The slider can be disassembled and assembled in the later stage, without disassembling the main body of the equipment.
Specification and dimensions: 12/16/20/25/30/35/45, a total of 6 standard widths
A single guide rail can be up to 4m long, and multiple sections can be spliced for unlimited travel
2. Single track split linear system (customized narrow space)
Two independent single guide rails, with adjustable spacing between rails; Roller boots can be directly attached to the device without the need for an additional slider base, making it extremely compact.
3. Matching slide/roller shoe subdivision
LWK: Standard ball slide seat, high-speed and smooth
LWR: Cross roller slide seat, high rigidity heavy-duty
LWS: Narrow ultra-thin slide seat, narrow installation space
LWF: Flange mounting slide, multiple mounting holes on the side/bottom
Core advantages of linear guide rail
Aluminum matrix+steel wire raceway, lightweight, low driving energy consumption, high acceleration
The steel wire raceway can be replaced separately, and the guide rail profile can be reused with low maintenance costs
Comes with felt/metal scraping dust accessories, optional clamping brake slider
Applicable Industries
Longmen light machine tool, packaging and conveying, medical equipment linear module, 3C testing equipment, automated doors and windows, solar photovoltaic handling
6、 Franke Full Series Selection Comparison Table
table
Series rolling element raceway process accuracy level stiffness cost core application
LEL Ball CNC Grinding Ultra High High Precision Rotary Table for Medical, Optical, and Semiconductor Applications
LER ball stamping special-shaped medium to low medium knitting machine, universal automated indexing disc
LEW Cross Roller Grinding Medium, Ultra, High, Medium, and Heavy duty Displacement Machine, Heavy duty AGV
LEG Double Row Ball Stamping/Grinding Medium, High, Medium, and Large Hollow Ring Equipment
LSA ball shaped stamping ordinary low and medium-sized integrated thin bearings
LV (A/B/C/D/E/G) ball/roller with built-in steel wire for high, medium, and high finished product slewing support, toothed drive turntable
LWK/LWR/LWS linear ball/roller embedded steel wire medium high to extremely high medium lightweight linear motion module
7、 Summary of typical industry applications
Medical equipment: LEL series (CT frame, surgical robot joints)
Textile Machinery: LER Series (Large Circular Machine Rotary Bearings, Franke Classic Applications)
Automated AGV/robot: LVB/LVE aluminum shell rotation, linear guide rail
Machine tool/heavy fixture: LEW cross roller, LVG double row roller slewing support
Optics/Semiconductors: LEL Ultra High Precision Grinding Bearings
Lightweight linear module: LWK/LWF aluminum linear steel wire track
Small gimbal/instrument: LSA ultra-thin integrated bearing

Franke is the inventor of Wire Race Bearing and a global market leader. The core design concept is "no need for rings, just steel wire tracks", which uses four independent steel wires to make the raceway, replacing the traditional heavy inner and outer rings of bearings. This structure makes the bearing extremely compact, lightweight, and cost-effective, providing significant advantages over traditional bearings in applications that require strict weight and space requirements.

🧬  Overview of Franke Wire Rail Bearing Series
Franke's product line is very diverse, mainly divided into three categories: Bearing Elements, Bearing Assemblies, and Linear Systems.

Bearing Elements
This is the core of Franke technology, where you can directly integrate prefabricated raceway components into your own equipment structure, achieving high customization. The following are the main component series:

Series Core Features Key Parameters/Features
LEL high precision, high operational performance - raceway: grinding raceway
-Installation space: 5.9mm-20.9mm
-Material: Hardened chromium silicon steel
-Diameter: 70mm -2000mm
LER Economy, Universal, High Dynamic - Roll Path: Rectangular Profile Roll Path
-Features: Economical price, easy to integrate
-Diameter: 70mm -2000mm
LEW High Rigidity, Impact Resistance - Type: Cross Roller Bearing
-Features: The rollers are arranged in a cross pattern, which can withstand the same high load in all directions
LED/LEG specific function optimization LED and LEG are both bearing component series, among which the LEG 8 model combines four raceway into one, simplifying the structure while maintaining four point contact.
Bearing assemblies
This is a complete bearing unit that can be installed and used immediately, with Franke's steel wire track bearing components integrated inside. If you don't want to design the installation structure yourself, you can directly choose these finished components.

Series Core Features Key Parameters/Features
LVA/LVB standard type, four point contact ready to use complete bearings designed for four point contact, insensitive to impact and vibration.
LVD/LVL Slewing Ring is designed specifically for slewing applications and is available in various materials such as steel (LVD) and aluminum (LVL).
LVE/LV is lightweight and high-performance, using lightweight materials such as aluminum, plastic, or 3D printing, which can reduce weight by up to 90% compared to traditional steel bearings.
Linear Systems
Franke has also applied his steel wire track technology to the field of linear motion.

Series Core Features Key Parameters/Features
FDA/FDB/FDC... The linear guide system includes multiple sub series such as FDA-K, FDB-K, FDC-K.
The core advantages are lightweight, quiet, and maintenance free. The main material is aluminum alloy, equipped with high-quality bearings, and the operation is quiet and smooth. The sealing design can achieve maintenance free operation.
💡  How to choose? Comparison of key characteristics
Accuracy priority: If the application requires extremely high operational accuracy and smoothness, the LEL series grinding raceway is the preferred choice.

Cost sensitive: If it is necessary to control costs while ensuring performance, the LER series provides an economical solution.

High rigidity requirements: For applications that require bearing heavy loads in all directions and high rigidity, the cross roller bearing LEW series is an ideal choice.

Weight sensitive: If the application has extreme weight requirements (such as aerospace, robotics), lightweight bearing components such as LVE/LVM or aluminum alloy linear guides can significantly reduce weight.

🔧  Core advantages and technological features
Ultimate Lightweight: The bearing itself can be very lightweight and can be integrated into lightweight materials such as aluminum and plastic, bringing significant system weight reduction.

Ultra high design freedom: You can freely choose the diameter (70-2000mm), installation space, and material of the bearing, which is deeply integrated with the equipment structure.

Four point contact design: Most Franke bearings use four point contact, which means that one ball can simultaneously withstand loads from radial, axial, and overturning moments.

Reliable performance: The working temperature range is usually from -30 ° C to+80 ° C, and the circumferential speed can reach 5 m/s.

Flexible product form: Provides individual bearing components (for integration) and ready to use components.

🎯  Typical application areas
Medical technology: CT scanners, surgical robots, etc.

Robotics technology: collaborative robots (Cobots), exoskeletons, etc.

Aerospace and Defense: Fields that require extreme weight reduction, such as radar systems and satellite components.

Mechanical manufacturing: textile machinery, machine tools, semiconductor equipment, etc.

If you want to know the detailed parameters or application cases of a specific series of Franke steel wire track bearings, you can always ask me again.

Linear guide bearings are also widely used in the large-scale medical equipment industry, where extremely high requirements are placed on operational smoothness, precision, low noise, and low energy consumption.

Due to their space-saving design and low cost, wire-roller bearings are also widely used in the food industry—for example, in vacuum filters, which are characterized by their compact size and cost-effectiveness.

Franke LEL/LER/LEW Three Main Main Steel Wire Track Bearings Standard Quick Reference Table
Terminology Note
KK Ø: Ball/roller center pitch diameter (model suffix number, such as LEL1.5-0070, KK Ø=70mm)
Section size: Bearing radial x axial installation thickness (mm)
Load unit: kN; Overturning moment C ₀ₘ: kNm; Weight: kg
C ₀ₐ/C ₀ᵣ: axial/radial static load; C ₐ/C ᵣ: Axial/Radial Dynamic Load
Unified material: 67SiCr5 quenched steel wire raceway, GCr15 rolling element, PA66 cage; Temperature -30~+80 ℃
1、 LEL Series | Precision Grinding Ball Wire Bearings (High Precision Medical/Optical/Semiconductor)

LEL profile structure

LEL dimension drawing
Overview of basic specifications for sub models
table
Model Ball Diameter Section Size (mm) Standard KK Ø Range Accuracy Class Highest Linear Velocity
LEL1.5 1.5mm 5.9 × 5.9 70~300mm P4 precision grade 5m/s
LEL2.5 2.5mm 9.2 × 9.2 160~900mm P4 precision grade 5m/s
LEL4 4mm 12.86 × 12.86 220~1500mm P4 precision grade 5m/s
LEL5 5mm 15.5 × 15.5 250~1800mm P4 precision grade 5m/s
LEL7 7mm 20.9 × 20.9 340~2000mm P4 precision grade 4.5m/s
Representative model load parameters (LEL1.5 small size)
table
Model KK Ø C ₀ₐ C ₀ᵣ C ₐ C ᵣ C ₀ₘ Weight
LEL1.5-0070    70    14    6    8    7    0.2    0.03
LEL1.5-0090    90    18    8    8    7    0.4    0.04
LEL1.5-0120    120    23    11    9    8    0.7    0.05
LEL1.5-0150    150    28    13    10    9    1.0    0.06
LEL4 Medium Representative
LEL4-0300: KK Ø 300, C ₀ₐ=121kN, C ₀ᵣ=48kN, C ₀ₘ=4.77kNm, weight 0.72kg
2、 LER Series | Economical Stamping Ball Wire Bearing (Automation/Textile/Universal Rotary Table)

LER section drawing
Overview of basic specifications for sub models
table
Model Ball Diameter Section Size (mm) Standard KK Ø Range Accuracy Class Highest Linear Velocity
LER1.5 1.5mm 5 × 6 40~200mm P6 universal grade 5m/s
LER2 2mm 7.5 × 8.9 80~400mm P6 universal grade 5m/s
LER3 3mm 11 × 13 120~900mm P6 universal grade 5m/s
LER4 4mm 14 × 16 180~1200mm P6 universal grade 5m/s
LER5 5mm 15.75 × 17.5 250~1800mm P6 universal grade 4.5m/s
Representative model load parameters
table
Model KK Ø C ₀ₐ C ₀ᵣ C ₐ C ᵣ C ₀ₘ Weight
LER1.5-0040    40    8    4    5    4    0.1    0.01
LER3-0300    300    142    68    52    31    5.2    0.61
LER5-1000    1000    962    450    82    70    32.6    3.75
LER Core Features
Stamping forming raceway, with a cost 30% lower than LEL; Pre tightening adjustable, suitable for knitting large circular knitting machines, AGV turntables, and lightweight robotic arms.
3、 LEW series | Cross roller steel wire bearings (heavy-duty high rigidity/positioner/heavy-duty AGV)

LEW roller profile

LEW integral ring component
Overview of basic specifications for sub models
table
Model Roller Diameter Section Size (mm) Standard KK Ø Range Accuracy Class Highest Linear Speed
LEW4 4mm 9.25 × 9.25 150~400mm P5 medium high precision 2m/s
LEW7 7mm 16.6 × 16.6 400~1200mm P5 medium high precision 2m/s
LEW4 (Small Cross Roller) Load Table
table
Model KK Ø C ₀ₐ C ₀ᵣ C ₐ C ᵣ C ₀ₘ Weight
LEW4-0150    150    81    32    34    16    2.4    0.27
LEW4-0200    200    109    44    41    20    4.4    0.31
LEW4-0300    300    168    66    52    27    9.8    0.54
LEW7 (Heavy Cross Roller) Load Table
table
Model KK Ø C ₀ₐ C ₀ᵣ C ₐ C ᵣ C ₀ₘ Weight
LEW7-0400    400    350    140    90    47    19.6    1.90
LEW7-0500    500    440    176    99    52    23.6    2.30
LEW7-0600    600    530    212    113    59    28.6    2.80
LEW Core Features
Roller line contact, overturning stiffness is 2.5-4 times that of LEL/LER ball bearing models; Anti impact, suitable for continuous high tilt torque working conditions, with low rotational speed.
4、 Comparison Table of Horizontal Selection of Three Major Series
table
Parameter dimension LEL Precision ball LER Economic ball LEW Cross roller
Rolling element four point contact ball four point contact ball single row intersecting cylindrical roller
Rolling process CNC precision grinding, stamping forming precision grinding
Precision P4 highest P6 ordinary P5 medium high
Rigid medium, high, medium, and extremely high (optimal for overturning)
Speed up to 5m/s, up to 5m/s, up to 2m/s
High, medium, and high costs
Section thickness 5.9~20.9mm ultra-thin 5~17.5mm flat 9.25/16.6mm
Typical scenarios include CT, optical turntable, semiconductor, precision indexing disc large circular machine, packaging equipment, lightweight AGV, ordinary turntable welding positioner, heavy-duty AGV, machine tool turntable, photovoltaic tracking
Supplementary selection remarks
Model naming convention: series ball/roller diameter pitch circle KK Ø, for example: LEW7-0400=LEW series, 7mm roller, pitch circle 400mm
The entire series supports customization: stainless steel anti-corrosion, ceramic non-magnetic ball bearings, ultra large diameter>2000mm, split split open ring
Installation requirements: The bearing body has no inner or outer rings, and the customer needs to machine matching grooves on the aluminum/steel base, relying on four steel wires to support it. The lightweight advantage of the whole machine is significant