Single-row cylindrical roller bearings are primarily designed to withstand high radial loads and are suitable for high-speed rotation. Their rolling elements maintain linear contact with the raceways, resulting in high rigidity and load-bearing capacity. Based on the inner and outer ring rib structures, they are classified into the following types: NU, N, NJ, NF, NUP, and NH. Each type has distinct structures and applicable operating conditions.
1. Detailed Characteristics of Each Type
NU Type
Features: Double ribs on the outer ring, no ribs on the inner ring, and axial movement of the inner ring.
Applications: Commonly used in non-locating bearings to accommodate axial shaft displacement due to thermal expansion, such as in motors and gearboxes.
N Type
Features: Double ribs on the inner ring, no ribs on the outer ring, and axial movement of the outer ring.
Applications: Suitable for applications where the outer ring needs to slide, such as long shaft supports and textile machinery.
NJ Type
Features: Double ribs on the outer ring, single rib on the inner ring, capable of supporting unidirectional axial loads.
Application: Suitable for shafts requiring unidirectional positioning, such as pumps and reducers.
NF Type
Features: Double ribs on the inner ring and a single rib on the outer ring limit unidirectional movement of the outer ring.
Application: Often used in combination with the NJ type for axial positioning.
NUP Type
Features: Double ribs on the outer ring and a single rib + flat retaining ring on the inner ring allow bidirectional axial positioning.
Application: Suitable for applications requiring fixed axial position, such as machine tool spindles.
NH Type
Features: Combining an NJ type bearing with an HJ type bevel retaining ring, it provides similar functionality to the NUP type but is easier to install.
Application: Suitable for applications requiring bidirectional positioning but limited space, such as construction machinery.
2. Summary
NU/N Type: Suitable for floating or fixed ends where axial displacement is permitted.
NJ/NF Type: Suitable for unidirectional axial positioning.
NUP/NH Type: Suitable for bidirectional axial positioning. The NUP type offers greater precision, while the NH type is easier to install.
High-speed adaptability: Cylindrical roller bearings are generally suitable for medium- and high-speed applications, with a higher maximum speed than tapered roller bearings.
Typical selection examples:
Motor floating end: NU206
Gearbox fixed end: NJ207 + NF207
Machine tool spindle: NUP209
Construction machinery: NH2307
