Time：2020.01.14 Source：Roller Bearings Suppliers
Double-row cylindrical roller bearings have two structures: cylindrical bore and conical bore (post bearing code plus K). Row cylindrical roller bearings have the advantages of compact structure, high rigidity, large bearing capacity, and small deformation after loading. The conical inner hole can play a role in adjusting the clearance in a short amount. It can simplify the structure of positioning device and facilitate the installation and disassembly.
Double-row cylindrical roller bearings have two structures: cylindrical bore and conical bore (post bearing code add K). This types of bearing has the advantages of compact structure, high rigidity, large bearing capacity, and small deformation after load. The conical inner hole can play a role in adjusting the clearance in a short amount. It can simplify the structure of positioning device and facilitate the installation and disassembly. Commonly used double-row cylindrical roller bearings have the following forms:
NN type bearings have no ribs on the outer ring, and there are ribs on both sides of the inner circle and a middle rod in the middle. It can allow displacement in two directions in the axial direction between the shaft and the bearing seat.
NNU bearings have ribs on both sides of the outer ring and middle bones in the middle, and no fins on the inner circle. It can allow displacement in two directions in the axial direction between the shaft and the bearing seat. Therefore, the type of structure is suitable as a moving end bearing. The cages of this type of bearings are mostly made of car-made solid cages.
NNF type bearings are double row full complement cylindrical roller bearings. The bearings consists of an outer ring with a middle rib and two inner rings with a double ridge. The bones of the inner circle guide the rollers, and the two inner rings are fixed together by a fastening collar. In addition to bearing large radial and axial loads, this structure can also take overturning moments, so it is often used as a fixed-end bearing.
NNF bearings adopt contact seals on both sides. The bearing is filled with grease. The working temperature of the fat is -50 ° C to + 110 ° C. However, due to the limitation of the sealing material, the working temperature of the bearing is limited to -40 ° C to + 80 ° C. Under the right operating conditions, NNF bearings with seals do not need to be maintained. If the bearings are exposed to water vapor or polluted the environment for a long time, and they are running at medium and high speeds, they can be adjusted through the oil grooves and holes on the outer ring The bearings are relubricated.
Application: Double-row cylindrical roller bearings have a small cross-section, high load capacity, and high rigidity. They are mainly used for machine tools, rolling stands, plastic rollers, grinders, and large gearboxes.
Rolling elements and cages: The rolling elements of double-row cylindrical roller bearings are double-row steel circular rolling elements. The cage materials used are mainly steel, nylon, brass, and other materials.
The commonly used method for adjusting the radial clearance of a full complement cylindrical roller bearing is as follows
1. The backlash of circular and elliptical bearing pads can be adjusted by manual grinding scraping or scraping after turning with padding in the bearing.
2. The top clearance of cylindrical and oval bearing pads can be adjusted manually by scraping or padding the bearing mid-face when the situation permits.
3. For multi-oil wedge-type bearing pads, scraping and adjusting the bearing pad clearance is not allowed in principle. If the permission is not suitable, a new bearing pad should be replaced.
4. For oily wedge tilting bearing pads, it is not allowed to repair the pads. If the clearance is not suitable, the invar blocks should be replaced. For tiles with adjustable thickness, you can adjust the number of tiles by adding a stainless steel pad under the pipe behind the pipe, or by reducing the width of the flooring. Note that for multi-oil wedge tilting bearing pads, the thickness error between the same group of pads should be less than 0.01mm.