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Needle Roller Bearing Inner Ring

A needle roller bearing inner ring is a component that acts as the inner raceway for needle rollers in a needle roller bearing assembly.

Inner rings are used when the shaft itself cannot be hardened or machined to the required specifications to serve as the raceway.And they are mainly as the component of machined needle roller bearings or heavy-duty needle roller bearings.

ZMS is supply inner rings in metric and inch series.Some inner rings include lubrication grooves and holes for relubrication.
Wide inner rings are available for applications with axial shaft movement or seals adjacent to the bearing.

We can supply by customer requirements from top brand like INA, IKO,NTN and to high quality Chinese needle roller bearing inner ring manufactures, we can fast response to customer.

The main series we can supply:
IR series, LR series, LRB series, MI series.

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Applications

Automotive: In engines, transmissions, and differentials.
Industrial Machinery: In conveyor systems, gearboxes, and electric motors.
Aerospace: In actuators and landing gear systems.
Other: Planetary gears, idler gears, and connecting rods.

Key Features

Space Efficiency: Enables compact bearing designs, ideal for space-constrained applications.
High Load Capacity: Supports heavy radial loads due to the large number of needle rollers.
Durability: Provides a hardened surface that resists wear and fatigue.
Cost-Effectiveness: More economical than machining the shaft to serve as the raceway, especially when bushings are not feasible.

Installation and Maintenance

Alignment: Ensure the inner ring is properly aligned with the outer ring and needle rollers.
Fixing: Inner rings can be located with shoulders or snap rings to prevent movement.
Lubrication: Regular lubrication is essential, and some designs include grooves and holes for relubrication.
Inspection: Periodically check for wear or damage to extend the bearing’s lifespan.

The Perfect Solution for Unhardened Shafts

Most drawn cup and machined needle roller bearings are designed to run directly on the shaft to save radial space. However, this requires the shaft to be hardened (HRC 58-64) and precision-ground. If your shaft material cannot be heat-treated, or if machining the shaft to bearing-grade tolerances is too expensive, ZMS Inner Rings provide the perfect, ready-to-mount raceway. Simply press our hardened inner ring onto your standard shaft, and your bearing is ready to roll.

IR Series vs. LR Series: Precision and Economy

We manufacture inner rings in two primary tolerance classes to suit your application and budget:

IR Series (Precision Ground): Manufactured from premium bearing steel, these rings are hardened and precision-ground on the raceway, the bore, and the end faces. They are the standard choice for high-speed, high-precision applications. Chamfers on the end faces facilitate easy mounting.
LR Series (Cost-Effective): While the raceway is precision-ground to bearing standards, the bore and end faces are turned (not ground) to wider tolerances. This makes the LR series an extremely cost-effective choice for applications where ultimate runout precision is not critical.

Extended Widths for Axial Displacement and Sealing

ZMS offers inner rings that are significantly wider than the mating needle roller bearing. Why is this important?

Axial Displacement: A wider inner ring allows the shaft to undergo thermal expansion or intentional axial movement without the needle rollers slipping off the raceway.
Optimal Seal Seating: The extended, precision-ground surface provides a perfect, smooth running track for adjacent lip seals, ensuring a tight sealing system that prevents oil leaks and contamination.

Lubrication Holes for Easy Maintenance

For applications where the bearing cannot be easily relubricated from the outside housing, ZMS provides inner rings featuring a lubrication hole in the center (often designated by an IS1 suffix). This allows grease or oil to be pumped directly through the hollow shaft and into the bearing rolling elements, drastically simplifying your maintenance routine.