NACHI 6311 ZZ NR Ball Bearing 55x120x29

Applications - Industrial & Mechanical Use

The NACHI 6311 ZZ NR ball bearing 55x120x29 is a robust single-row deep groove ball bearing designed for demanding industrial and mechanical systems. Its compact dimensions and strong load tolerance make it suitable for electric motors, pumps, gearboxes, conveyor drives, and rotating machinery.

Thanks to its precise engineering and reliable performance, this bearing is widely used in industrial automation, automotive assemblies, heavy-duty drive units, and maintenance applications where smooth rotation and continuous operation are essential.

Advantages - Shielding and NR Snap Ring Feature

Manufactured by NACHI, this 6311 ZZ NR combines excellent structural quality with advanced performance features:

• ZZ metal shields protect the internal components from dust and debris while allowing higher speed operation compared to rubber-sealed variants.

• NR designation indicates an integrated snap ring groove and ring for secure axial positioning in the bearing housing — simplifying installation and increasing assembly stability.

• The deep groove design ensures balanced load distribution and quiet, vibration-free operation.

The bearing’s construction provides high durability, reduced friction, and reliable performance over extended service intervals — ideal for industrial maintenance and OEM applications.

Technical Specifications

• Model: 6311 ZZ NR

• Brand: NACHI

• Bearing type: Deep groove ball bearing

• Dimensions: 55x120x29 mm

• Shielding: ZZ - double metal shields

• Snap ring: NR - groove and ring included

• Load types: Radial loads; moderate axial loads

• Typical applications: Motors, gearboxes, industrial drives

Main Description

The NACHI 6311 ZZ NR ball bearing 55x120x29 is engineered for demanding rotational systems where reliable performance and long service life are priorities. It is a single-row deep groove bearing optimized for radial load support and capable of handling moderate axial forces.

Its double metal shields (ZZ) effectively seal the interior against contaminants while maintaining low friction torque and efficient operation at higher speeds. The integrated NR snap ring groove and ring allow secure mounting and prevent axial displacement — a valuable feature in machine tool spindles, transmission housings, and mounted bearing units.

This bearing is pre-lubricated at the factory with high-quality grease that reduces the need for frequent relubrication, yet it remains serviceable for maintenance intervals. Its precision tolerance and rigid construction deliver consistent performance even in environments with vibration, temperature variation, or continuous operation.

Industrial engineers, maintenance professionals, and machine builders choose the NACHI 6311 ZZ NR when they need a dependable ball bearing that supports efficiency, uptime, and predictable mechanical behavior in complex systems.

FAQ - Frequently Asked Questions

What does the “ZZ” in 6311 ZZ NR mean?
“ZZ” indicates double metal shields on both sides of the bearing. These shields help protect against contamination while enabling higher speed operation.

What is the “NR” feature?
“NR” signifies a snap ring groove and snap ring that allows the bearing to be axially secured in the housing.

Can this bearing handle axial loads?
Yes, it can support moderate axial loads in addition to radial loads.

Is the bearing pre-lubricated?
Yes, the bearing comes factory-lubricated with grease suitable for general industrial use.

Should this be mounted in a bearing housing?
It can be used standalone or installed in an appropriately sized bearing housing for improved assembly stability.