How much do you know about cylindrical bearings?

Cylindrical bearingsare divided into three categories: single-row cylindrical roller bearings, double-row cylindrical roller bearings and four-row cylindrical roller bearings.

Single row cylindrical bearings

NU-type bearing has retaining edges on both sides of the outer ring and no retaining edges on the inner ring. However, both sides of the inner ring of N-type bearing have retaining edges, while the outer ring has no retaining edges. Therefore, in a certain range, the machine shaft is allowed to make two-way axial displacement relative to the bearing box, that is, it can bear the length change of the machine shaft caused by thermal expansion. Therefore, it is suitable for non-positioning bearing.

NJ cylindrical bearings has retaining edges on both sides of outer ring and retaining edges on one side of inner ring. NF cylindrical roller bearing has retaining edges on both sides of inner ring and retaining edges on one side of outer ring. Therefore, the machine shaft can be axially positioned in one direction.

NUP cylindrical bearings have retaining edges on both sides of the outer ring, retaining edges on one side of the inner ring and movable retaining edges on the other side. Therefore, the bearing can position the machine shaft in two directions.

It also produces high-precision single-row cylindrical bearings with 1:12 conical holes in the inner ring for machine tool spindles.

Double row cylindrical bearings

The produced double-row cylindrical bearings are precision grade bearings for machine tool spindles, and can also be used for other precision machines. Type NN is the inner ring with retaining edge and the outer ring without retaining edge. However, NNU type has outer ring with retaining edge and inner ring without retaining edge. For the convenience of users, the lubricating device is installed, and the structure with oil groove and oil hole on the outer ring is the main one (suffix code W33). According to users' needs, products with cylindrical hole and conical hole can be provided.

measure

The basic dimensions of bearings listed in the table conform to ISO15-1981.

Allowable inclination angle

Adjusting the contact state between the roller and the raceway surface properly can not only prevent the abnormal load of the contact surface, but also allow the inclination of the inner ring and the outer ring caused by the installation error. The allowable inclination angle of  bearings is:

-Narrow 10, 2,3 and 4 series bearings 3.5'

-wide type 22 and 23 series bearings 1.5'

Sometimes, a larger inclination angle is allowed, but it depends on the load and the required life. No inclination angle is allowed for double-row cylindrical roller bearings.

tolerance

Production of single-row cylindrical bearings with tolerance below P5. At the same time, we produce single-row cylindrical roller bearings and double-row cylindrical roller bearings with tapered holes in the inner ring for machine tool spindles with P5 and above tolerances and SP and UP special tolerances.

Radial clearance

Standard products of single-row cylindrical bearings have basic group clearance. Single-row cylindrical bearings can also provide C3 group clearance, and some can also provide larger C4 group clearance. Standard products of double-row cylindrical bearings have C1 group clearance, cylindrical bore can also provide C2 and C3 group clearance products, and tapered bore bearings can also provide C2 group clearance products.

Cage

The cages of NU, NJ, NF and NUP type of single-row cylindrical bearings are usually the same as those of N type bearings.

Cylindrical bearings with glass fiber reinforced nylon 66 cage (suffix code TN) are used for operation below +120℃. Solid brass cage (suffix M) can be used for bearing devices that require continuous operation under extremely high temperature or harsh conditions. Bearings with glass fiber reinforced nylon 66 cage and brass cage as standard design can also adopt stamped steel cage according to user's requirements.

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