WO2016091671A1

WO2016091671A1 - A roller bearing as well as a cage suitable for such a roller bearing

Info

Publication number: WO2016091671A1
Application number: PCT/EP2015/078300
Authority: WO
Inventors: Hans DE RUIG; Jos Holsnijders
Original assignee: Aktiebolaget Skf
Priority date: 2014-12-08
Filing date: 2015-12-02
Publication date: 2016-06-16
Also published as: GB201421769D0; GB2533088A

Abstract

A roller bearing comprises at least an outer ring with a radially outer raceway, an inner ring with a radially inner raceway, a number of rollers, a cage and sealing structures. The rollers and cage are disposed between the outer ring, the inner ring and the sealing structures located on opposite sides of the outer raceway and the inner raceway. The cage comprises at least a first and a second wave shaped holding plate, which holding plates are located opposite to each other. Each holding plate comprises at least two pockets and a bridge part extending between two adjacent pockets, wherein in opposite pockets of two holding plates at least one roller of the number of rollers is located. Each pocket comprises a flange extending away from the roller towards the inner ring. The flange of each pocket comprises a central part and side parts on each side of the central part, which side parts are located closer to the nearest sealing structure than the central part.

Description

A roller bearing as well as a cage suitable for such a roller bearing

FIELD OF THE INVENTION The invention relates to a roller bearing comprising at least an outer ring with a radially outer raceway, an inner ring with a radially inner raceway, a number of rollers, a cage and sealing structures, which rollers and cage are disposed between the outer ring, the inner ring and the sealing structures located on opposite sides of the outer raceway and the inner raceway, which cage comprises at least a first and a second wave shaped holding plate, which holding plates are located opposite to each other, each holding plate comprises at least two pockets and a bridge part extending between two adjacent pockets, wherein in opposite pockets of two holding plates at least one roller of the number of rollers is located, each pocket comprises a flange extending away from the roller towards the inner ring.

The invention also relates to a cage suitable for such a roller bearing. BACKGROUND OF THE INVENTION

In such a roller bearing, known from WO2012011408A1 balls are located in opposite pockets of the first and a second wave shaped holding plates. The balls are being lubricated by means of grease. During the rotation of the bearing the grease will be forced out of the space between the ball and its pockets. A cage of the bearing of WO2012011408AI comprises axially overhanging portions between two adjacent balls to suppress the reduction of the grease between the ball and its pockets due to the rotation of the bearing.

By the known roller bearing it will be difficult to guide grease that has been moved towards the outer ring and onto the sealing structures back into the space between the ball and its pockets.

SUMMARY OF THE INVENTION

One of the objects of the invention is to provide a roller bearing whereby the disadvantages of the above mentioned roller bearing have been overcome.

This object is achieved by the roller bearing according to the invention in that the flange of each pocket comprises a central part and side parts on each side of the central part, which side parts are located closer to the nearest sealing structure than the central part. Due to the shape of the flange, grease on the sealing structure will be forced by a side part into an opening between the central part and the sealing structure towards the roller and into the space between the roller and its pockets.

Furthermore, due to the flange, the height of the pocket in radial direction can be much smaller than without such a flange. Due to the reduced height, the contact area between the roller and the pocket is also reduced so that less grease is needed for the lubrication of the contact area. Due to the flange, the pocket with its reduced height will be strong enough to resist the forces exerted on the pockets by the roller.

An embodiment of the roller bearing according to the invention is characterized in that at the nearest sealing structure the central part and the side parts of the flange of the pocket form a circular- shaped edge.

Due to the circular-shaped edge grease will gradually be moved towards the central part through the opening between the central part and the sealing structure towards the roller.

Another embodiment of the roller bearing according to the invention is characterized in that each bridge part comprises a flange extending towards the nearest sealing structure, wherein the flange of each bridge part comprises a central part and side parts on each side of the central part, which side parts are located closer to the sealing structure than the central part.

Due to the shape of the flange, grease between the side parts will be forced by a side part into the opening between the central part of the flange of the bridge part and the sealing structure towards a space between the flanges of the opposite bridge parts and the inner ring. From this space the grease will be moved in circumferential direction of the inner ring towards the nearest roller.

Another embodiment of the roller bearing according to the invention is characterized in that between two opposite bridge parts and the inner ring a passage is located extending in a circumferential direction of the inner ring between rollers on opposite sides of the bridge parts.

During rotation of the bearing the grease will be moved through the passage in circumferential direction of the inner ring towards the nearest roller so that a good distribution of the grease over each individual roller as well as over the several rollers will be obtained.

Another embodiment of the roller bearing according to the invention is characterized in that the at least first and second wave shaped holding plates are ring-shaped forming a ring-shaped cage.

By such a ring-shaped cage all rollers of the roller bearing can be maintained on the desired position by one single cage.

Another embodiment of the roller bearing according to the invention is characterized in that each of the at least first and second wave shaped holding plates is made as a whole. In this manner each holding plate can easily, fast and reliable be manufactured. Furthermore, the cage is obtained by connecting the holding plates to each other without additional parts.

Another embodiment of the roller bearing according to the invention is characterized in that the rollers are balls.

Especially for balls, like in deep groove ball bearings or trust bearings, the cage as described above has proven to improve the distribution of grease, reuse of grease and grease storage (buffering) and thus the lubrication of the rollers of the bearing.

An embodiment of the invention relates to a ring-shaped cage for such a roller bearing comprising at least a sealing structure, which cage comprises at least a first and a second wave shaped holding plate being ring-shaped, which holding plates are located opposite to each other, each holding plate comprises at least two pockets and a bridge part extending between two adjacent pockets, each pocket comprises a flange extending away from the other holding plate towards the inside of the ring- shaped cage, wherein the flange of each pocket comprises a central part and side parts on each side of the central part, wherein in use the side parts are located further away from the other holding plate than the central part.

Such a cage can easily be made, for example of holding plates, each made as a whole, to improve in use in a bearing the distribution of grease and thus the lubrication of the rollers of the bearing.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a perspective, partially cross section of a first embodiment of a roller bearing according to the invention,

figure 2 is a perspective view of a first holding plate of the roller bearing as shown in figure 1, figure 3 is a perspective view of a second holding plate of the roller bearing as shown in figure 1, figure 4 is a perspective view of the first and second holding plate as well as balls of the roller bearing as shown in figure 1,

figure 5 is an enlarged perspective rear view of a detail of figure 4,

figure 6 is an enlarged perspective front view of a detail of figure 4,

figure 7 is an enlarged top view of a detail of figure 1,

figure 8 is an enlarged bottom view of a detail of figure 1,

figure 9 is a perspective, partially cross section of a second embodiment of a roller bearing according to the invention,

figure 10 is a perspective view of the first and second holding plate as well as balls of the roller bearing as shown in figure 9, figure 11 is shows an enlarged front view of a part of figure 9,

figure 12 is a perspective, partially cross section of a third embodiment of a roller bearing according to the invention.

In the drawings, like reference numerals refer to like elements.

DESCRIPTION OF THE FIGURES

The figures 1-8 show different views of a first embodiment of a roller bearing 1 according to the invention. The roller bearing 1 is a deep groove ball bearing comprising an outer ring 2 with a radially inner surface providing a radially outer raceway 3, an inner ring 4 with a radially outer surface providing a radially inner raceway 5, a set of bearing balls 6 radially interposed between the outer raceway 3 and the inner raceway 5 and a cage 7 for holding the balls 6. The cage 7 comprises a first wave shaped holding plate 8 and a second wave shaped holding plate 9, which holding plates 8, 9 are located opposite to each other.

As can best be seen in the figures 2 and 4, the first wave shaped holding plate 8 is an endless ring, comprising a number of pockets 10, each with a partially hemispherical surface similar to the surface of the balls 6. Each set of two adjacent pockets 10 are connected to each other by means of a bridge part 11.

Each bridge part 11 comprises at least a relatively flat base portion 12 extending in a circumferential direction indicated by double arrow Pi and in a radial direction of the rings 2, 4. The base portion 12 is provided with a passage 13 having a width WP in the circumferential direction.

On each side of the passage 13, the bridge part 11 is provided with an extension 14 being folded over a folding line 15 extending in the circumferential direction and located on the upper side 16 of the holding plate 8. Each extension 14 has a width WE in the circumferential direction. The width WP of the passage 14 is about the same as the width WE of the extensions.

Each passage 13 is bounded in the circumferential direction by edges 17.

As can best be seen in figures 3 and 4, the second wave shaped holding plate 9 is an endless ring, comprising a number of pockets 20, each with a partially hemispherical surface similar to the surface of the balls 6. Each set of two adjacent pockets 20 are connected to each other by means of a bridge part 21.

Each bridge part 21 comprises at least a relatively flat base portion 22 extending in a circumferential direction indicated by arrow Pi and in a radial direction of the rings 2, 4. The base portion 22 is provided with a lip 23 having a width WL in the circumferential direction. De width WP of the passage 13 is larger than the width WL of the lip. The difference or clearance between the width WP and WL is preferably in de order of 0,5 - 1,5 millimeter, depending on the diameter of the bearing 1. Preferably, a smaller bearing has a smaller clearance.

The lip 23 is obtained by providing the base portion 22 with two cuts perpendicular to the upper side 24 of the holding plate 8 and bending the lip 23 located between the two cuts over a folding line 25 located between ends of the cuts and extending parallel to the upper side 24. The lip 23 is bent in axial direction into an S-shape, whereby a lower part 26 of the lip is connected at the folding line 24 to the base portion 22 and an upper part 27 extends parallel to the base portion 12 of the bridge part 11 of the first holding plate 8, when the lip 23 is located in the passage 13·

In figure 4 the two holding plates 8, 9 are positioned opposite each other, whereby between opposite pockets 10, 20 a cavity is formed in which a ball 6 is being disposed. The opposed bridge parts 11, 21 are connected to each other by means of the extensions 14 of the bridge part 11, which are positioned over the upper side 24 of the base portion 21. The extensions 14 prevent the holding plates 8, 9 for moving with respect to each other in axial direction but do not prevent movement of the holding plates 8, 9 with respect to each other in the circumferential direction as indicated by double arrow Pi. By connecting the opposed bridge parts 11, 21 to each other, the lip 23 of bridge part 21 is positioned inside the passage 13·

Since the width WL of the lip 23 is smaller than the width WP of the passage 13, the holding plates 8, 9 can move with respect to each other in the circumferential direction as indicated by double arrow Pi if different forces are applied by a ball 6 on the opposed pockets 10, 20 until the lip 23 is in abutment with an edge 17 of the passage 13·

Due to the clearance WP-WL in the circumferential direction indicated by arrow Pi of the holding plates 8, 9, the holding plates 8, 9 align themselves on the surfaces of the balls 6. This alignment corrects for the manufacturing errors of the tolerances of the two holding plates 8, 9, being displaceable connected to each other.

As can also be seen in the figures 1-6, the roller bearing 1 comprises two sealing structures, each comprising an annular ring shaped seal 30 located between the outer ring 2 and the inner ring 4. The seals 30 are located on opposite sides of the outer and inner raceways 3, 5· The seals 30 maintain grease being used for lubrication inside a space bounded by the outer ring 2, the inner ring 4 and the seals 30.

The first and second wave shaped holding plates 8, 9 are each provided with first flanges 31, second flanges 32 and third flanges 33·

The pockets 10, 20 are provided with the first flanges 31 which extend away from the ball 6 inside the respective pocket 10, 20 towards the inner ring 4 and the seal 30. Each first flange 31 comprises a central part 34 and side parts 35 on each side of the central part 34, which side parts 35 are located closer to the seal 30 than the central part 34· The distance is measured to the seal 30 located on the same side of the ball 6 as the first flange 21. This seal 30 is the nearest seal 30. Near the seal 30 the central part 34 and the side parts 35 of the first flange 31 of the pocket 10, 20 form a circular-shaped edge 36. The distance between the side part 35 and the seal 30 is about 0,5 millimeter.

Figures 7 and 8 are a top view and a bottom view of the same ball 6 in radial direction of the bearing 1, showing clearly the central part 34 and the side parts 35 of the first flange 31 in relation to the seal 30.

The bridge parts 11, 21 are provided with the second flanges 32 extending towards the nearest seal 30, wherein the second flange 32 of each bridge part 11, 21 comprises a central part 37 and side parts 38 on each side of the central part 37, which side parts 38 are located closer to the seal 30 than the central part 37·

The first flange 31 and the second flange 32 are connected to each other by means of the third flange 33-

Between two opposite bridge parts 11, 21 and the inner ring 4 a passage 39 is located extending in a circumferential direction of the inner ring 4 between balls 6 on opposite sides of the bridge parts 11, 21.

The inner ring 4 is provided on both sides of the raceway 5 with flat ring shaped surfaces 40.

The side parts 35 are located as close as possible to the surface 40 without being in contact with the surface 40 in a manner that the side parts 35 will be able to remove nearly all and preferably all the grease which has become attached to the surface 40. The grease will be removed by rotating the cage 7 and the balls 6 located therein with respect to the inner ring 4, whereby the grease will be scraped of the surface 40 by the side parts 35. The edge 36 of the central part 34 is located at a distance of the surface 40 of, for example 0,5 millimeter.

The grease that is being moved by the side parts 35 will enter an opening 41 located between the edge 36, the surface 40 and the seal 30 towards the balls 6 located inside the pockets 11, 21.

In the same manner grease that is being moved by the third flanges 33 and the side parts 38 of the second flange 32 will enter an opening 42 located between the central part 37 of the second flange 32 and the surface 40 into the raceway 5 and the passage 39 located below the bridge parts 11, 21.

Due to the presence of the flanges 31, 32, 33 the height H of the pockets 10, 20 in radial direction can be relatively small whilst still having enough strength to withstand the forces exerted by the balls 6 on the pockets 10, 20. The height H of the pockets 10, 20 depends amongst others on the type of bearing, the size of the balls 6 and the desired strength.

Figures 9-11 show perspective views of a second embodiment of a roller bearing 51 according to the invention. The roller bearing 51 differs from the roller bearing 1 in that the first flanges 52 of the pockets 10, 20 comprises a central part 53 and side parts 54 on each side of the central part 53, which side parts 54 are located closer to the seal 30 than the central part 53· The distance is measured to the seal 30 located on the same side of the ball 6 as the first flange 52. This seal 30 is the nearest seal 30. Near the seal 30 the central part 53 and the side parts 54 of the first flange 52 of the pocket 10, 20 form a circular-shaped edge 55· The distance between the side part 54 and the seal 30 is about the same as the distance between the side part 35 and the seal 30. The distance between the central part 53 and the seal 30 is smaller than the distance between the central part 34 and the seal 30. Due to the smaller distance also the opening 56 between the edge 55 and the surface 40 is smaller.

Figure 12 shows a perspective view of a third embodiment of a roller bearing 6l according to the invention. The roller bearing 6l differs from the roller bearing 51 in that the second flanges 62 of the bridge parts 11, 21 comprises a central part 63 and side parts 64 on each side of the central part 63, which side parts 64 are located closer to the seal 30 than the central part 63. The distance is measured to the seal 30 located on the same side of the bridge part 11, 21 as the second flange 62. This seal 30 is the nearest seal 30. Near the seal 30 the central part 63 and the side parts 64 of the second flange 62 of the bridge part 11, 21 form a circular-shaped edge 65. The distance between the side part 64 and the seal 30 is smaller than the distance between the central part 63 and the seal 30. The edge 65 is located above the surface 40, whereby an opening 66 is provided between the edge 65 and the surface 40 through which grease can flow from the surface 40 into the raceway 5·

The first flange 52 and the second flange 62 are connected to each other by means of the third flange 67.

The size of each flange 31, 32, 33, 52, 62, 67 can be determined based amongst others on the required height H, the forces applied on the pockets 10, 20 and the amount, viscosity and kind of grease, The first and second wave shaped holding plates 8,9 are each made as whole from a metal like steel or plastic, like polyamide.

It is also possible that the bridge part comprises one extension, which is bent over the bridge part of the other holding plate.

It is also possible that the extension is located adjacent to the lip.

It is also possible that instead of balls other rolling elements are being used.

Instead of a seal the sealing structure may comprise a shield.

The person skilled in the art will realize that the present invention is by no means limited to the preferred embodiments. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in 25 practicing the claimed invention, from a study of the drawings, the disclosure, and

the appended claims. LIST OF REFERENCE SIGNS

1 roller bearing

2 outer ring

3 outer raceway

4 inner ring

5 inner raceway

6 ball

7 cage

8 holding plate

9 holding plate

10 pocket

11 bridge part

12 base portion

13 passage

14 extension

15 folding line

16 upper side

17 edge

20 pocket

21 bridge part

22 base portion

23 lip

24 upper side

25 folding line

26 lower part

27 upper part

30 seal

31 first flange

32 second flange

33 third flange

34 central part

35 side part

36 edge 37 central part

38 side part

39 passage

40 surface

42 opening

51 roller bearing

52 first flange

53 central part

54 side part

55 edge

61 roller bearing

62 second flange

63 central part

64 side part

65 edge

66 opening

67 third flange

H height

Pi double arrow

WE width of the extension WP width of the passage WL width of the lip

Claims

1. A roller bearing (l, 51, 6l) comprising at least an outer ring (2) with a radially outer raceway (3), an inner ring (4) with a radially inner raceway (5), a number of rollers, a cage (7) and sealing structures located on opposite sides of the outer raceway (3) and the inner raceway (5), which rollers and cage (7) are disposed between the outer ring (2), the inner ring (4) and the sealing structures, which cage (7) comprises at least a first and a second wave shaped holding plates (8, 9), which holding plates (8, 9) are located opposite to each other, each holding plate (8, 9) comprises at least two pockets (lO, 20) and a bridge part (ll, 2l) extending between two adjacent pockets (lO, 20), wherein in opposite pockets (lO, 20) of two holding plates (8, 9) at least one roller of the number of rollers is located, each pocket (lO, 20) comprises a flange (31, 52) extending away from the roller towards the inner ring (4), characterized in that the flange (31, 52) of each pocket (lO, 20) comprises a central part (34, 53) and side parts (35, 54) on each side of the central part (34, 53), which side parts (35, 54) are located closer to the nearest sealing structure than the central part (34, 53)·

2. A roller bearing (l, 51, 61) according to claim 1, characterized in that at the nearest sealing structure the central part (34, 53) and the side parts (35, 54) of the flange (31, 52) of the pocket (lO,

20) form a circular-shaped edge (36, 55)· 3· A roller bearing (l, 51, 6l) according to claim 1 or 2, characterized in that each bridge part (ll, 2l) comprises a flange (32, 56) extending towards the nearest sealing structure, wherein the flange (32, 56) of each bridge part (ll, 2l) comprises a central part (37, 63) and side parts (38, 64) on each side of the central part (37, 63), which side parts (38, 64) are located closer to the sealing structure than the central part (37, 63).

4· A roller bearing (l, 51, 61) according to one of the preceding claims, characterized in that between two opposite bridge parts (ll, 2l) and the inner ring (4) a passage (39) is located extending in a circumferential direction of the inner ring (4) between rollers on opposite sides of the bridge parts (ll,

21) .

5- A roller bearing (l, 51, 6l) according to one of the preceding claims, characterized in that the at least first and second wave shaped holding plates (8, 9) are ring-shaped forming a ring-shaped cage (7).

6. A roller bearing (l, 51, 6l) according to one of the preceding claims, characterized in that each of the at least first and second wave shaped holding plates (8, 9) is made as a whole.

7· A roller bearing (l, 51, 6l) according to one of the preceding claims, characterized in that the rollers are balls (6).

8. The cage (7) according to one of the preceding claims, which ring-shaped cage (7) is suitable for a roller bearing comprising at least a sealing structure, which cage (7) comprises at least a first and a second wave shaped holding plate (8, 9) being ring-shaped, which holding plates (8, 9) are located opposite to each other, each holding plate (8, 9) comprises at least two pockets (lO, 20) and a bridge part extending between two adjacent pockets (lO, 20), each pocket (lO, 20) comprises a flange (32, 56) extending away from the other holding plate (8,9) towards the inside of the ring-shaped cage (7), characterized in that the flange (32, 56) of each pocket (lO, 20) comprises a central part (37, 63) and side parts (35, 54) on each side of the central part (37, 63), wherein the side parts (35, 54) are located further away from the other holding plate (8, 9) than the central part (37, 63).

9- A cage (7) according to claim 8, characterized in that the central part (34, 53) and the side parts (35, 54) of the flange (31, 52) of the pocket (lO, 20) form a circular-shaped edge (36, 55)·

10. A cage (7) according to claim 8 or 9, characterized in that each bridge part comprises a flange (32, 56) extending in use towards the nearest sealing structure, wherein the flange (32, 56) of each bridge part (ll, 2l) comprises a central part (37, 63) and side parts (38, 64) on each side of the central part (37, 63), wherein in use the side parts (38, 64) are located closer to the sealing structure than the central part (37, 63).

11. A cage (7) according to one of the preceding claims 8-10, characterized in that between two opposite bridge parts (ll, 2l) a passage (39) is located extending in a direction from one pocket (lO, 20) to an adjacent pocket (lO, 20) of the same holding plate (8, 9)· 12. A cage (7) according to one of the preceding claims 8-11, characterized in that the at least first and second wave shaped holding plates (8, 9) are ring-shaped forming a ring-shaped cage (7).

13· A cage (7) according to one of the preceding claims 8-12, characterized in that each of the at least first and second wave shaped holding plates (8, 9) is made as a whole.