KYOCM Technology Knowledge: Solid cage with spherical pocket for deep groove ball bearings

Solid cage with spherical pocket for deep groove ball bearings

Abstract: a spherical pocket solid cage for deep groove ball bearings is introduced. The cage adopts the steel ball guiding 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 way of thinking for bearing design and research.

Key words: deep groove ball bearing; Solid cage; Steel ball guide


Small and medium-sized deep groove ball bearings produced in batch generally use steel plate stamping wave cage, which has good strength and 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 kinds of cages are commonly used in occasions with low speed and stable load. If the bearing speed is high, the acceleration is large, or it bears heavy load and impact load, from the perspective of lubrication and strength, copper cage is required. The common copper cage is a two half steel rivet connection structure, which adopts the outer ring or inner ring edge guide, and the pocket shape is cylindrical. Due to the small guide clearance of the cage of this structure, it is difficult for the lubricating medium to enter, and the ferrule edge is easy to rub, wear and heat with the outer diameter or inner diameter of the cage during high-speed operation, which seriously affects the normal operation of the bearing.


After analyzing and studying the structure and performance of all kinds of cages, the high strength and high resistance of copper cages make comprehensive use of the spherical pocket and rolling element guiding mode of stamped wave shaped or engineering plastic cages. A two-half steel riveted copper cage with spherical pocket is developed, and 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.


1 Main features of new structure cage

The structure of spherical pocket cage is shown in Figure 1.  

Material: brass (zcuzn38mn2pb2- gb/t1176 or zcuzn40pb2- gb/t1176) or bronze (zcua110fe3mn2 - gb/t1176).

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

Pocket shape: spherical (composed of two hemispheres)

Guiding mode: steel ball guiding

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.




2 Design calculation of cage

It can be seen from Figure 1 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 SΦ. 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 steel ball, attention should be paid to the guidance gap between the steel ball and the cage pocket during the design!, The clearance is too large to form a steel ball for accurate guidance; If the clearance is too small, friction, heating and even jamming may occur between the two due to poor lubrication.


Inner diameter Dci = Dcp - KcdDw

Outer diameter Dc= Dcp + KcDw

Dci and Dc need to meet the constraints: Dci- d2> ε n D2- Dc>  ε u

Ball pocket radius SR = 0.5( Dw+  ε)

Half cage width Bc1= 0.5Bc


The diameter of the center circle where the Dcp pocket is located, that is, the diameter of the center circle where the steel ball is located.

Dw - steel ball diameter

Kc - coefficient can be taken as Kc= 0 during preliminary calculation five

d2 - inner ring flange diameter

D2 - outer ring flange diameter

ε n, ε U - guide clearance of inner ring and outer ring during edge guide

ε - 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.


3 Processing of cage pocket

The special ball end milling cutter is designed to cut into the pocket from the end face and mill it. The shape and surface roughness of the pocket are very high, requiring highly skilled operators and high-precision processing equipment.


Research and experiments show that the use of spherical pocket copper cage can realize the accurate guidance of steel balls, improve the lubrication performance of bearings, reduce the friction and temperature rise of bearings, ensure the good operation quality of bearings, and improve the service life and reliability of bearings.


More about KYOCM Deep Groove Ball Bearing

Deep groove ball bearings are the most widely used bearing type and are particularly versatile. They have low friction and are optimized for low noise and low vibration which enables high rotational speeds. They accommodate radial and axial loads in both directions, are easy to mount, and require less maintenance than other bearing types.

Deep Groove Ball Bearing 

KYOCM deep groove ball bearings include 6000 Series bearing, 6200 Series bearing, Inch Series bearing, Extended Inner Ring Deep Groove Ball Bearings, 6300 Series bearing, 6400 Series bearing, Double Row Deep Groove Ball Bearings, 16000 Series bearing.


Deep groove ball bearings are widely used in many industries for decades. A deep groove is formed on each inner and outer ring of the bearings enabling them to sustain radial and axial loads or even combinations of both. As the leading deep groove ball bearing factory, KYOCM Bearings owns abundant experience in designing and producing this type of bearing.


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