ITS Technology Knowledge: Development of Spherical Pocket Solid Cage for Deep Groove Ball Bearing

Structural performance analysis of various cages, proposal of new structure cage and the main features and development of the new structure cage.

 

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Abstract: This paper introduces a kind of spherical pocket solid cage for deep groove ball bearing. The structure cage adopts the rolling element guide mode, which can guide more accurately, and can greatly improve the lubrication performance of the bearing, ensure that the bearing has a good running state, and provide a new idea for the design and Research of the bearing.

 

Key words: spherical pocket cage rolling element guide

 

There are three common cage structure types of deep groove ball bearings: 1.Steel plate stamping wave cage; 2.Engineering plastic cage; 3.Two half steel riveted metal solid (cylindrical pocket L) cage.

 

This paper introduces a new structure of solid cage for deep groove ball bearing.

 

1. Structural performance analysis of various cages

For the batch production of small and medium-sized deep groove ball bearings, steel plate stamping wave cage is generally used, which has high strength, light weight and is widely used. Engineering plastic cage has the advantages of light weight, good self-lubricating performance, impact resistance, vibration resistance and noise reduction, but it also has the disadvantages of poor dimensional stability, large hygrothermal expansion, low strength and poor heat resistance. These two cage structures are usually used in occasions with low speed and stable load. If the bearing speed is high, the acceleration is large, or it bears impact load, it needs to use copper cage from the perspective of lubrication and strength.

 

The common structure of copper cage is two half steel riveted structure, which adopts outer ring or inner ring edge guide, and the pocket shape is cylindrical, as shown in Figure 1. Due to the small guide clearance of the cage of this structure, it is difficult for the lubricating medium to enter (as shown in Figure 2). During high-speed operation, the edge of the ferrule is easy to rub, wear and heat with the outer diameter or inner diameter of the cage, which seriously affects the normal operation of the rolling bearing.

 

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Figure 1

 

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Figure 2

2. Proposal of new structure cage

How to solve the above problems? After analyzing and studying the structure and performance of various cages, a new idea of cage structure is put forward, that is, combining the advantages of the above three cages, using the spherical pocket of stamped wave shaped or engineering plastic cages, the rolling body guide mode, and the characteristics of copper cages with high strength, high wear resistance, high reliability and suitable for high-speed operation, a two half steel riveted copper cage with spherical pocket is developed (see Figure 3), The movement of the cage is accurately guided by the steel ball. In this way, the clearance between the edge of the ferrule and the outer or inner diameter of the cage can be increased, so that the grease is easy to enter and sufficient grease accommodation space can be provided (see Figure 4).

 

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Figure 3

 

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Figure 4

 

Research and experiments show that the use of spherical pocket copper cage can realize the accurate guidance of the rolling element, improve the lubrication performance of the bearing, reduce the friction and temperature rise of the bearing, ensure the good running quality of the bearing, prolong the service life of the bearing, and improve the reliability of the bearing.

 

3. The main features of the new structure cage 

It can be seen from the structural comparison between figure 1 and figure 3. The main differences between the spherical pocket cage and the cylindrical pocket cage are:  pocket shape,  guiding mode,  the gap between the ferrule edge and the outer or inner diameter of the cage,  pocket processing method,  lubrication and use effect.

 

Main features of the new structure cage:

1) Material: brass (ZCuZn38Mn2Pb2 - GB / T1176 or ZCuZn40Pb2 - GB / T1176) or bronze (ZCuA110Fe3Mn2 GB / T1176)

2) Structural form: two half cages are connected by half round head steel rivets

3) Pocket shape: spherical (composed of two hemispheres)

4) Guiding mode: steel ball guiding

5) The gap between the retaining edge of the ferrule and the outer diameter or inner diameter of the cage is increased, and grooves are made on the outer diameter and inner diameter of the cage, so that the lubricating medium can easily enter and flow out.

 

4. Development of new structure cage

4.1 Design of cage

It can be seen from Figure 3 that the spherical pocket cage is composed of two identical half cages. The pocket shape of each half cage is hemispherical Sr, and the ball center is on one end face. The two half cages are connected with rivets to form a spherical pocket s. The structure and size of the two half cages are exactly the same, which can ensure interchangeability.

 

In order to avoid the loosening and breaking of the rivets connecting the two halves of the cage, the diameter of the rivets can be appropriately increased in the design (generally by one gear) to ensure sufficient connection strength.

 

The steel balls are located in the ball pockets of the two half cages. In order to ensure the precise guidance of the rolling element, attention should be paid to the guidance gap (8) between the steel ball and the cage pocket during the design. The gap is too large to form the precise guidance of the rolling element. If the clearance is too small, friction, heating and even jamming may occur between the two due to poor lubrication.

After using the rolling element guidance, the gap between the ferrule edge and the outer diameter or inner diameter of the cage can be increased, so as to avoid friction and wear between them, and grooves are made on the outer diameter and inner diameter of the cage, so that the grease can easily enter and provide sufficient grease accommodation space.

 

4.2 Calculation of main dimensions

4.2.1 Inner diameter of cage:

Dci=Dcp—Kc × Dw

 

4.2.2 Outer diameter of cage:

Dc=Dcp+Kc × Dw

Dci and DC need to meet the constraints:

Dci—d2>n

D2 - dc>u4

 

4.2.3 Ball pocket radius:

SR=0.5 × (Dw+)

 

4.2.4 Width of half cage:

Bcl=0.5 × Bc

 

Dcp - the diameter of the central circle where the pocket is located, that is, the diameter of the central circle where the steel ball is located

Dw - diameter of steel ball

Kc - coefficient, kc=0.5 can be taken during preliminary calculation

D2: - diameter of inner ring flange

D2: - diameter of outer ring flange

n, U - Guide clearance of inner ring and outer ring during edge guidance

guide clearance between steel ball and pocket

Bc - total width of cage

 

The design calculation of other dimensions is the same as that of the two halves of the cylindrical pocket cage.

 

5. Conclusion

For the solid cage used in deep groove ball bearings, the adoption of rolling element guidance to solve the problem of high reliability operation of bearings under high-speed and alternating load is an innovation in bearing structure design and enlargement technology. It makes the bearing have better operation quality: more accurate guidance, more sufficient lubrication, low vibration, low noise, high rigidity, low friction and long service life. The spherical pocket copper cage has a good market prospect and promotion value. It will replace some products with backward structure and produce good economic and social benefits.

 

More about ITS Deep Groove Ball Bearing:

ITS deep groove ball bearing top quality brand has guaranteed production and highly active management.

 

ITS manufactures a full range of deep groove ball bearings (DGBBs). These versatile bearings are the most common type and serve a wide variety of industries.

Besides radial loads, the bearings can take axial loads in both directions and offer low frictional torque and high-speed components ideal for applications requiring low noise and vibration.

 

In addition to open varieties, these bearings can have steel shields or come pre-lubricated with grease maintained by rubber seals installed on one or both sides. Snap rings are sometimes used on the outside diameter of the outer ring.

 

Cages are generally made of pressed steel, though large bearings and bearings designed for high-speeds may use machined brass cages.

 

Deep Groove Ball Bearing 


2022-08-08

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