Drawn Cup Needle Roller Bearing Guide

But not all drawn cup needle roller bearings are the same. There are three main types: HK, BK, and SCE. Each one has a special job. In this guide, you will learn how they are different and which one is right for your project.

What Is a Drawn Cup Needle Roller Bearing?

A drawn cup needle roller bearing is made from a thin, hard steel shell. The shell is "drawn" into a cup shape. Inside the cup, there are many thin rollers. These rollers are called needle rollers. They are long and thin, like needles.

Because the rollers are thin, you can fit many of them in a small space. This allows the bearing to handle heavy loads without taking up much room. The cup itself is the outer ring. This makes the bearing light and cheap to make. Most of these bearings have a cage. The cage keeps the rollers apart so they do not rub against each other. You will find them in cars, factory machines, and robots.

HK Series vs BK Series vs SCE Series

The three most common series are HK, BK, and SCE. The main difference is how the ends are made. HK bearings are open on both ends. BK bearings have one closed end. SCE bearings are a heavy-duty version of the HK style.

Here is a simple table to help you compare:

Open End vs Closed End — Does It Matter?

Yes, the end type matters a lot. It changes where you can use the bearing.

▪ Open end (HK and SCE): Both ends are open. Oil can flow through the bearing. This keeps it cool and clean. Use open-end bearings in high-speed machines like electric motors or gearboxes. The oil splashes through the bearing to remove heat.

▪ Closed-end (BK): One end is sealed shut. Dirt, dust, and water cannot go through. This is perfect for car wheels or conveyor rollers that face mud or rain. The closed end also holds grease inside. You do not need an oil system. Just pack it with grease and install it.

▪ Rule of thumb: If the area is clean and you have oil flow, choose HK. If the area is dirty or you want to use grease, choose BK.

Lightweight Alloy Housing Compatibility

Many modern machines use lightweight alloy housings. Alloys are soft. Old bearings could damage these soft housings. But a drawn cup needle roller bearing is different. The steel cup is hard and strong. The cup itself fits directly into the alloy housing. The rollers turn inside the steel cup. This means the soft alloy never touches the moving rollers.

Why is this good? You can make the machine lighter. You save money on materials. And you do not need a separate heavy outer ring. For electric vehicles and drones, this is a big advantage.

Automotive & Robotics Use Cases

You will find these bearings everywhere. Here are real-world uses:

Automotive:

▪ Transmission: HK bearings support spinning gears.

▪ Connecting rods: SCE bearings handle the pounding of an engine.

▪ Water pumps: BK bearings keep grease in and water out.

▪ Alternators: Small HK bearings allow high-speed rotation.

Robotics:

▪ Robot arms: Drawn cup bearings fit inside small joints.

▪ Servo motors: They support the motor shaft with low friction.

▪ End effectors (grippers): Lightweight bearings help fingers move fast.

Robots need small, light parts. A drawn cup needle roller bearing is perfect. It gives high load capacity in a tiny space. This allows robot designers to build smaller, faster arms.

How to Read a Drawn Cup Bearing Part Number

The part number tells you the size. Once you learn the code, you can pick the right bearing quickly.

Let us take an example: HK 2010

▪ HK = Series name (open end)

▪ 20 = Inside diameter in millimeters (20 mm)

▪ 10 = Width in millimeters (10 mm)

Another example: BK 3016

▪ BK = Series name (closed end)

▪ 30 = Inside diameter (30 mm)

▪ 16 = Width (16 mm)

SCE example: SCE 168

▪ SCE = Series name (heavy duty, open end)

▪ 16 = Inside diameter in sixteenths of an inch (16/16" = 1 inch)

▪ 8 = Width in eighths of an inch (8/8" = 1 inch)

Tip: HK and BK use metric sizes (millimeters). SCE uses inch sizes. Always double-check your machine's manual before ordering.

Conclusion

Choosing the right needle roller bearing is easy if you remember three things. First, use HK for high speed and oil flow. Second, use BK for dirty areas and grease. Third, use SCE for heavy shock and lower speed. All three types are drawn cup needle roller bearings. They save space, work with lightweight housings, and keep your cars and robots running.