do you know how many kinds of cages for needle bearings ?
The structure of needle roller bearings can be roughly divided into the following types:
1 Needle roller bearings with inner ring and outer ring.
2. Needle roller bearings without inner ring.
3. Needle roller bearings without cages on inner and outer rings.
In the first two structures mentioned above, it can be with or without a cage, because the full needle roller (without cage) bearing has a low speed, but its load-bearing capacity is extremely large, so the application is still Need to retain this structural form. Needle roller bearings without an inner ring can be divided into two structures: a solid outer ring and a stamped outer ring. Due to the different structure of needle roller bearings, the shape of the cage is also different. Each cage structure has its own characteristics. Several commonly used bearing cages are described as follows:
1. “K” shaped bearing cage
“K” shaped bearing cage
Its main advantage is that the rigidity and strength are high, and the outer diameter guide or inner diameter guide can be adopted in the design according to requirements. Tube material processing is used in production, except for the window punching process, no complicated molds are required, so it is not only suitable for mass production, but also for small batch production, especially for small-sized bearings, using “K”-shaped cages. It has better manufacturability than the “M”-shaped cage. For double-row and multi-row needle roller bearings, from the analysis of the processability of the double-row or multi-row window holes of the cage, the “K” shape has better conditions than the “M” shape, so the “K” shape cage becomes the current needle roller retainer. The common structural form of the frame is due to the development of bearings. There is a trend to increase the number of rolling elements. Due to the excessive thickness of the wall of the “K”-shaped cage, such as increasing the number of window holes, it is easy to cause the distortion of the cage lintel during processing. The number of needles of the “K”-shaped cage is generally less than that of the “M”-shaped cage of the same series.
2. “M” shaped bearing cage
Its main advantage is that it can maintain a larger number of needle rollers and the lubrication conditions are also better. The cage can only be guided by the outside, which is a better cage structure for single row needle roller bearings. “M”-shaped cages can be produced with tube materials. Only in the window punching process, it is more difficult to master than “K”-shaped cages. It is suitable for mass and small batch production, and it is also one of the commonly used structures.
3. Thin-wall stamping “M”-shaped bearing cage
Not only can it keep more needle rollers, but the needle rollers have the largest length, so that the bearing can achieve the most ideal load capacity. In addition, the cage requires surface treatment to obtain better rigidity and improve wear resistance. Due to the limitation of thin wall, this kind of cage can only be applied to medium-sized bearings.
4. “I” shaped bearing cage
Needle roller bearings without inner and outer rings are one of the structures designed by our country. This kind of cage has the advantages of simple geometry, better craftsmanship, and fewer procedures. It is recommended to use 20 steel pipes to process, which can meet the requirements of not falling or clamping the roller needle after punching the window hole, and does not need to carry out the rolling printing process.
5. New “K” shaped bearing cage
It is one of the structures designed by our country. This product also has the advantage that the needle cannot be dropped or clamped after the window hole is punched. In foreign countries, this structure is only used for bearings with a solid outer ring, and the outer diameter does not require locking needle rollers. The improved domestic “K”-shaped structure has ideal manufacturability. It has been gradually developed through the summary of domestic production practices and needs further testing and improvement.
6. “O” shaped bearing cage
It is mostly used for bearings with a stamped outer ring, and the cage requires surface heat treatment to enhance rigidity.
7. “M” shaped bearing cage without ribs
This structure is stronger than the above-mentioned “O”-shaped cage and has better lubrication conditions. The cage requires surface heat treatment. This structure is also mostly used for bearings with stamped outer rings.
8. Two-half combined bearing cage
As shown in the figure above, the two-half combined cage has different structures. Firstly, the integral cage with the equally divided window holes is processed, and then the annular ribs at both ends of the window holes of the cage are cut off. When the bearing is installed, two more long needles with the same height as the cage are added. As shown in Figure b, a small opening is cut off at both ends of the cage window hole, and two roller needles of equal length are installed during installation. Figure c is a cut on a wider lintel on the cage to form a gap between the two halves of the cage without adding additional needles. Bearings with this structure cause uneven load distribution of the bearing due to the unequal division of the needle roller positions, and the lintels on both sides of the cage bear greater stress, which will cause damage to the bearing when the speed is high. The working performance of the bearing is not as good as the bearing of the above two structures.
In addition, there are structures such as “W”-shaped bearing cages and “I”-shaped bearing cages, but they are not as widely used as the above-mentioned cages.
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