Cage-Needle Roller Bearings

Yousen’s needle roller bearings are supplied with a pressed steel cage, a machined solid cage or glass fiber reinforced polyamide 66 on other engineering plastics. The cages of materials are identified by a suffix, these suffix are explained in the chapter “DY Bearing Designation”.

Equivalent Dynamic (Static) Load-Needle

In order to maintain bearings working in a good condition, a minimum load must be imposed on bearings, particularly on bearings working at high speeds, with high accelerations, or with the load direction changing frequently, because under these working conditions, inertial force of balls and cage and lubricant friction will have bad influence on the rotation of bearings, and detrimental sliding movement may be caused.

The minimum load of a needle roller bearing can be obtained from：

Fmin = 0.02C

Where

C-Basic dynamic loading rating, N

Type-Needle Roller Bearings

Type NA, RNA

Yousen’s standard needle roller bearings are NA type, which has flange or spring lock ring at the two sides of outer ring, and a flangeless inner ring. There are two structures including single row and double rows. Either the single or double-row bearings can be produced into type NA with inner ring, or type RNA without inner ring.

For larger sizes, there are circularity lubrication grooves and holes on outer ring. Outer assembly of type NA's (outer ring, needle rollers and cage) are non-separated, but inner ring can be parted from outer assembly.

When needle rollers bearings are without an inner ring, its rollers would have direct contact with shaft surface. In this way, the hardness and dimension of journal must reach the requirements of bearing raceway.

Type NAV, RNAV

Bearings of type NAV and RNAV are filled with rollers without a cage. These are another type derived from type NA and RNA. Their carrying capacity is larger than type NA and RNA. However the rotating speeds are lower.

Type NAO

Type NAO have a flangeless inner ring and outer ring, with two structures as single row and double rows. For double-row needle roller bearing, it has a lubrication groove and hole on the outer ring.

Type K

Type K is also called “needle and cage assembly” without an inner and outer ring, it has the smallest radial dimension of bearing. It works directly on shaft surface and bearing housing, so the matching shaft and bearing houses must ensure hardness and dimensional accuracy.

Type NAOL

Similar to the type NAO, bearings of type NAOL have flangeless inner ring and outer ring.

Type NAL

Similar to type NA, these bearings have flanges or spring lock rings at the two sides of outer ring, but, are without a flange on inner ring.