KOYO BH 1812 28.575x38.1x19.05 - Full Complement Needle Roller Bearing

KOYO BH 1812 28.575x38.1x19.05 - Full Complement Needle Roller Bearing

KOYO BH 1812 is a full complement drawn cup needle roller bearing with dimensions 28.575x38.1x19.05 mm, equivalent to 1 1/8 x 1 1/2 x 3/4 inch. The BH series uses a thin-walled drawn outer cup and a full complement of needle rollers without a cage. This open-ended bearing is supplied without an inner ring and is designed primarily for high radial load capacity within a compact radial installation space.

Technical Specifications - KOYO BH 1812

Manufacturer: KOYO / JTEKT
Designation: BH-1812 / BH 1812
Product type: Needle roller bearing
Series: BH inch series
Design: Drawn cup, full complement
Rolling elements: Needle rollers
Cage: No cage, full complement
Inner ring: Not included
Design: Open ends
Raceway diameter Fw: 28.575 mm
Outside diameter D: 38.1 mm
Width C: 19.05 mm
Metric dimensions: 28.575x38.1x19.05 mm
Imperial dimensions: 1 1/8 x 1 1/2 x 3/4 inch
Primary load direction: Radial
Mounting: Press fit into housing

Dimensions 28.575x38.1x19.05 mm

The main identification dimensions of BH-1812 are:

Fw: 28.575 mm = 1 1/8 inch
D: 38.1 mm = 1 1/2 inch
C: 19.05 mm = 3/4 inch

The imperial dimensions are particularly important when identifying this bearing in machinery originally designed using inch-size components.

The designation BH 1812 should therefore be verified together with the complete dimensions and bearing construction when selecting a replacement.

Full Complement Needle Roller Design

Unlike caged needle roller bearings, BH-1812 uses a full complement of needle rollers.

Eliminating the cage allows more rolling elements to be installed within the available space. This increases the effective rolling contact area and provides a high radial load-carrying capability relative to the bearing's compact external dimensions.

This construction is particularly useful in applications where radial load capacity is more important than very high rotational speed.

Drawn Cup Outer Ring

The outer ring of KOYO BH 1812 is manufactured as a thin-walled drawn cup.

This construction minimizes the radial section of the bearing. With a raceway diameter of 28.575 mm and an outside diameter of only 38.1 mm, the bearing can provide needle roller support without requiring the installation space associated with conventional roller bearings.

The drawn cup is intended to be installed with the appropriate interference fit in a correctly dimensioned housing bore.

Bearing Without Inner Ring

KOYO BH 1812 is supplied without an inner ring.

In a standard arrangement, the shaft itself acts as the inner raceway for the needle rollers. The shaft raceway must therefore meet the required dimensional accuracy, hardness, geometry and surface-finish requirements.

Where the shaft cannot be used directly as a raceway, a suitable separate inner ring can be considered. IR-1416 is commonly referenced as a matching inner ring for the BH-1812 bearing arrangement.

Radial Load Capacity

The long, small-diameter needle rollers provide a relatively large contact area between the rolling elements and raceways.

For this reason, BH-series bearings are primarily intended to accommodate radial loads.

The compact cross-section combined with full complement construction makes BH-1812 useful in machinery where:

• installation space is limited
• substantial radial load must be supported
• an inch-size bearing is required
• the shaft can function as the inner raceway

Open-Ended Construction

BH-1812 has an open-ended design, allowing the shaft to pass completely through the bearing.

This differentiates it from closed-end drawn cup needle roller bearings used where the end of the shaft terminates inside the bearing position.

The open configuration should be verified when replacing an existing bearing because an open and closed-end bearing are not automatically interchangeable.

Typical Applications

KOYO BH 1812 can be used in appropriately designed:

• industrial gearboxes
• transmission mechanisms
• agricultural machinery
• drive systems
• compact shaft assemblies
• material handling equipment
• industrial machinery
• mechanical power transmission systems

The final bearing selection should consider radial load, speed, lubrication, shaft hardness, shaft surface finish, housing accuracy and operating temperature.

Replacement Identification - BH 1812

When identifying a replacement, verify:

Brand: KOYO / JTEKT
Designation: BH-1812
Bearing type: Full complement needle roller bearing
Construction: Drawn cup
Dimensions: 28.575x38.1x19.05 mm
Imperial dimensions: 1 1/8 x 1 1/2 x 3/4 inch
Inner ring: Without inner ring
Cage: Without cage
Ends: Open
Primary loading: Radial

Matching only the outside diameter is not sufficient. The complete dimensions, full complement construction and open-ended design should correspond to the original bearing.

FAQ - KOYO BH 1812

What are the dimensions of KOYO BH 1812?
The bearing dimensions are 28.575x38.1x19.05 mm, equivalent to 1 1/8 x 1 1/2 x 3/4 inch.

What type of bearing is BH-1812?
It is a full complement drawn cup needle roller bearing from the inch-size BH series.

Does KOYO BH 1812 have a cage?
No. It uses a full complement of needle rollers without a cage.

Does BH-1812 include an inner ring?
No. The standard bearing is supplied without an inner ring, allowing a suitably prepared shaft to function as the inner raceway.

What does the 28.575 mm dimension correspond to?
It corresponds to 1 1/8 inch and represents the nominal needle roller raceway diameter.

Is BH 1812 an open-ended bearing?
Yes. BH-1812 is an open-ended drawn cup needle roller bearing.

What type of loads does BH-1812 primarily support?
It is designed primarily for radial loads, offering substantial load capacity relative to its compact radial dimensions.

Why is a full complement design used?
Using more needle rollers increases the rolling contact area and allows greater radial load capacity within a limited installation envelope.