Four-Row Tapered Roller Bearings
High-Capacity Roll-Neck Bearings for Hot and Cold Rolling MillsBearing Type: Four-Row Tapered Roller Bearing
Series: 380000 Type (77000 Type)
Bore Diameter: 120-1320 mm
Load Rating: High radial and bidirectional axial loads
Radial Capacity: Approx. 3 times a single-row tapered bearing
Speed Suitability: Lower limiting speed.
Technical Specifications
| Specification | Details |
|---|---|
| Bearing Type | Four-Row Tapered Roller Bearing |
| Series | 380000 Type (77000 Type) |
| Bore Diameter | 120-1320 mm |
| Load Rating | High radial and bidirectional axial loads |
| Radial Capacity | Approx. 3 times a single-row tapered bearing |
| Speed Suitability | Lower limiting speed |
| Material | GCr15 / GCr15SiMn / G20Cr2Ni4A; customized materials available |
| Precision Class | P0 / P6 / P5 / P4 |
| Temperature Range | -20°C to +150°C |
| Lubrication | Grease or oil lubrication |
| Cage | Pressed-steel cage; pin-type cage for large sizes |
| Customization | Size, structure, sealing and material options |
Four-Row Tapered Roller Bearings Overview
Four-row tapered roller bearings are among the principal bearing arrangements used for rolling-mill roll necks. Four rows of tapered rollers provide very high radial capacity together with substantial axial capacity in both directions, making the design suitable for heavy combined loads.
Radial capacity is approximately three times that of a comparable single-row tapered roller bearing, although limiting speed is lower. The bearing locates the shaft or housing in both axial directions within its axial clearance, and radial and axial clearance can be adjusted by changing the thickness of the inner and outer spacers.
Four-Row Heavy-Load Performance
The four-row arrangement spreads load across a large rolling-contact area, providing the capacity and rigidity needed for heavily loaded work-roll and cogging-mill roll necks while also supporting axial forces from both directions.
- Very high radial load capacity
- Large bidirectional axial capacity
- Bidirectional axial location
- High rigidity for roll-neck duty
Roll-Neck Mounting and Serviceability
For convenient mounting and removal, four-row tapered roller bearings are normally installed with a clearance fit on the roll neck. Correct spacer matching and clearance control are essential for even load sharing, stable temperature and reliable service life.
- Clearance fit for convenient mounting and removal
- Radial and axial clearance adjusted by spacers
- Pressed-steel or pin-type cages by size
Four illustrated 380000 Type (77000 Type) configurations
380000 Series Structure Options
| Structure | Series | Selection Guidance |
|---|---|---|
| Structure 1 | 380000 Type (77000 Type) | Standard open configuration; select by bearing size and roll-neck geometry |
| Structure 2 | 380000 Type (77000 Type) | Alternative ring and spacer arrangement for application boundaries |
| Structure 3 | 380000 Type (77000 Type) | Extended inner-ring configuration for specified mounting conditions |
| Structure 4 | 380000 Type (77000 Type) | Alternative extended configuration selected by load and installation requirements |
Materials, Lubrication and Customization
Standard material choices include GCr15, GCr15SiMn and G20Cr2Ni4A. Grease or oil lubrication can be specified according to speed, load and mill environment. Open designs are standard, while sealed and other special structures can be developed for application-specific requirements.
Radial load capacity : Approx. 3× single-row tapered bearing
Typical Applications
- Hot-rolling mill work-roll necks
- Cold-rolling mill work-roll necks
- Cogging-mill roll necks
- Heavy steel rolling equipment
- Bidirectionally loaded roll supports
- Customized sealed roll-neck arrangements
