China Slewing Ring Bearings
1.Spacer blocks and cages for slewing ring bearings
The isolation block and cage of the swivel bearing, expressed as spacer and CAGE in English, have the main functions of reducing friction, coordinating operation efficiency, distributing loads, and guiding the circumferential trajectory of the rolling elements. It is an integral part of the overall design of the slewing ring bearings.
Cage (that is, bearing cage, also known as bearing cage, foreign name: cage), refers to the bearing parts that partially wrap all or part of the rolling body and move with it, to isolate the rolling body, and usually guide the rolling body and keep it in the slewing ring bearings.
2 Main functions 1. Keep a proper distance between the rolling elements to prevent the rolling elements from contacting each other to reduce friction; 2. Make the rolling elements evenly distributed, so that the load is evenly distributed; 3. Guide the rolling elements in the no-load area to improve the bearing rolling condition to prevent damaging slippage.
The cage must withstand the stress caused by friction, strain and inertial force, and also withstand the chemical corrosion of lubricants, additives in lubricants or substances generated by their aging, organic solvents or coolants.
Therefore, the design and material of the cage are extremely important for its performance and the reliability of the slewing ring bearings.
3 types of cages Bearing cages are divided into stamping cages (Figure 1), solid cages (Figure 2) and strut cages 1. The advantages of stamping cages are light weight and large internal space, which can facilitate the entry of lubricants ; 2. The solid cage is usually allowed to have a higher speed.
When the slewing ring bearings has other forms of motion other than rotation at the same time, especially in the case of high speed, the machined metal cage should also be used; 3. The pillar cage is penetrated by pins Roller with perforations to secure both ends of the pin to the washer.
This cage is lighter and can accommodate more rollers and is only used in oversized roller bearings. 4. Cage materials Cage materials mainly include stamped steel, machined steel, stamped brass, machined brass, polymeric materials, etc.
Stamped steel cages have high strength and can be surface treated to reduce friction and wear; machined steel cages are generally used for oversized bearings or where brass cages are not suitable; stamped brass cages are used in part Small bearings; Machined brass cages are generally not affected by bearing lubricants and can be cleaned with ordinary lubricants.
Brass cages should not be used for operating temperatures above 250; Polymeric material (nylon 66, nylon 46, etc.) cages Compared with metal cages, it has many advantages such as good toughness, friction and wear resistance, impact resistance, acid resistance and corrosion resistance.
Whether the slewing bearing is a ball bearing or a ball bearing, the spacer block and the cage are indispensable. The role of the cage:
1. Reduce friction between rolling elements
2. Coordinate, distribute and guide the movement direction and movement trajectory of the rolling elements
3. Standardize the force balance of rolling elements
4. On the basis of bearing forces, especially vertical, inclined and multi-directional forces, the application of integral cages and segmented cages is very necessary to prevent rolling elements from being squeezed during gravity and movement, causing hard friction
5. In high-speed bearings, the overall cage is the first factor in the design
6. In order to reduce friction, reduce noise and reduce wear, the application of copper cage, PTFE cage and PA66 cage is very critical.
The influence of the segmented cage and the integral cage on the structure and life improvement of the slewing ring bearings, in a word, can improve the rotation flexibility of the slewing ring bearings, improve the reliability, and significantly improve the life and efficiency of the slewing bearing.
The material of the segmented cage is divided into steel cage, copper cage and nylon cage, as well as PA66 cage, PTFE cage, the overall cage is generally steel cage or copper cage, or steel inlaid copper cage shelf.
Because rolling, especially steel balls or balls, is not pure rolling during the rotation of the bearing, it may also be sliding friction. By dividing and conquering the segmented cage or the overall cage, the stability and regularity of the individual running state of the rolling elements are obtained. For steel balls, it is free from backlog and chaos.
Compared with fast isolation, it can achieve individual breakthroughs. Compared with balls, its importance is more prominent. In the bearing cost, it is a good technical suggestion if the user is advised to use a segmented cage or an integral cage.
Especially in the case of inclined installation, vertical installation, or multi-directional force, the integral cage should be the first choice for slewing bearings.
