Rolling bearings

Abstract

To reduce assembling man-hours for an ultra-large bearing by simplifying assembling work for a shield.SOLUTION: A rolling bearing 10 includes an inner ring 12, an outer ring 11, a plurality of rolling elements 13, 14, and a shield 50. One of the inner ring 12 and the outer ring 11 has a first side face 34a in one of the axial directions, the other of the inner ring 12 and the outer ring 11 has a second side face 17 in one of the axial directions, located in one of the axial directions further than the first side face 34a. The shield 50 is provided on the first side face 34a, arranged annularly as a whole with a plurality of shield members 43 tied to one another via a plurality of covering members 49, and opposed to the other of the inner ring 12 and the outer ring 11 in the radial direction. The plurality of covering members 49 are arranged across tied parts s of the shield members 43, and assembled on both sides of the tied parts s while overlapping with the shield members 43 in the radial direction.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to preventing the intrusion of foreign matter into rolling bearings, particularly extra-large bearings. [Background technology]

[0002] In large equipment such as ladle turrets that transport molten steel in steelmaking facilities and stackers and reclaimers used in port operations, rotating parts are supported by slewing ring bearings, which are extra-large bearings (bearings with a nominal outer diameter exceeding approximately 800 mm: JIS B0104-1991). As with general industrial rolling bearings, these large rolling bearings must be prevented from infiltrating with foreign matter to maintain smooth rotation over the long term. Patent Document 1 discloses a large rolling bearing with a rubber seal member fixed to the outer ring and a lip tip that contacts the inner ring to prevent foreign matter from infiltrating through the gap between the outer and inner rings.

[0003] However, in the case of slewing ring bearings 90 used in steelmaking equipment, there is a risk that scattered high-temperature scale and the like will hit the sealing member directly, burning the rubber and causing holes, etc. Therefore, as shown in Figure 11, measures are sometimes taken to prevent foreign matter from entering the bearing by installing an annular shield 94 that protrudes from the side of the inner ring 91 and covering the entire surface of the sealing member 93 with grease G. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2010-508471 Summary of the Invention [Problem to be solved by the invention]

[0005] The slewing bearing 90 has a nominal outer diameter of about 4 to 5 meters, and the circumferential length of the shield 94 exceeds 10 meters, making it extremely difficult to manufacture a one-piece shield 94. Therefore, conventional shields 94 are divided circumferentially, with multiple shield members 94a arranged circumferentially and installed in a ring-shaped configuration as a whole. Circumferentially adjacent shield members 94a are welded to each other to prevent grease G covering the seal member 93 from leaking from the joints between the shield members 94a.

[0006] However, if the circumferential length of each shielding member 94a is shorter than the required dimension, assembling multiple shielding members 94a in close proximity to one another in the circumferential direction may result in a large circumferential gap between the first and last assembled shielding members 94a, making it impossible to weld them together.For this reason, in the past, the shielding members 94a were manufactured with a longer circumferential length, and the circumferential width of the last assembled shielding member 94a was reduced to adjust it so that all of the shielding members 94a were in contact with each other. As described above, in the case of extra-large bearings, assembling the shield 94 requires a great deal of labor and requires personnel with welding skills, which is a special task, so assembling the rolling bearing requires a great deal of labor.

[0007] In view of the above circumstances, the present invention aims to simplify the assembly work of a shield that prevents foreign matter such as scale from entering the inside of a bearing, thereby reducing the number of steps required to assemble an extra-large bearing. [Means for solving the problem]

[0008] One aspect of the present invention is a rolling bearing comprising: an inner ring having an inner raceway surface on its outer circumference; an outer ring having an outer raceway surface on its inner circumference; a plurality of rolling elements arranged to be rollable between the inner raceway surface and the outer raceway surface; and a shield that prevents foreign matter from entering, wherein the outer ring and the inner ring rotate relatively around a central axis, wherein one of the inner ring and the outer ring has a first side surface on one side in the axial direction, and the other of the inner ring and the outer ring has a second side surface on one side in the axial direction that is positioned more axially than the first side surface, the shield is attached to the first side surface, and a plurality of shielding members are connected by a plurality of shielding members so as to be arranged in an annular shape centered on the central axis, and radially oppose the other of the inner ring and the outer ring, and the plurality of shielding members are arranged across joints between the shielding members adjacent in the circumferential direction, and are assembled to the shielding members on both sides of the joints so as to overlap radially with the shielding members. [Effects of the Invention]

[0009] According to the present invention, the work of assembling the shield that prevents the intrusion of foreign matter such as scale into the extra-large bearing is simplified, thereby reducing the number of steps required to assemble the extra-large bearing. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a cross-sectional view showing the shape of an axial cross section of a rolling bearing according to a first embodiment. [Figure 2] FIG. 4 is a front view of the single first inner ring as viewed in the axial direction from the first back surface side. [Figure 3] FIG. 3 is an axial cross-sectional view taken along line AA in FIG. 2. [Figure 4] FIG. 4 is a partial cross-sectional view showing an enlarged area where a protective member is incorporated. [Figure 5] FIG. 10 is a perspective view showing the form of a single shield member. [Figure 6] FIG. 4 is a partial perspective view showing a state in which the shielding member is assembled. [Figure 7] FIG. 10 is an axial cross-sectional view at the position of the second screw hole. [Figure 8]FIG. 10 is an axial cross-sectional view of a rolling bearing according to a second embodiment. [Figure 9] FIG. 10 is a partial cross-sectional view showing an enlarged view of a region where a protective member according to a second embodiment is incorporated. [Figure 10] FIG. 10 is a partial cross-sectional view showing a modified example of the shield assembly state. [Figure 11] FIG. 1 is a cross-sectional view showing the shape of an axial cross section of a conventional rolling bearing. DETAILED DESCRIPTION OF THE INVENTION

[0011] (First embodiment) Embodiments of the present invention will be described in detail with reference to the drawings. Fig. 1 is a cross-sectional view showing the axial cross section of a rolling bearing 10 according to a first embodiment of the present invention. This rolling bearing 10 is a slewing bearing used in the rotation support portion of a ladle turret in continuous casting equipment, and is an extra-large bearing with a nominal bearing outer diameter of approximately 4 to 5 m. An extra-large bearing is a bearing with a nominal bearing outer diameter exceeding approximately 800 mm (JIS B0104-1991). In Fig. 1, a base 98 and an arm 99 of the ladle turret are each schematically shown by a two-dot chain line.

[0012] The ladle turret is a device that transports steel that has been heated and molten in a converter toward a mold. The ladle turret is equipped with a fixedly installed base 98 and an arm 99 that rotates in a horizontal plane around a vertical central axis m, and ladles (not shown) that transport molten steel are attached to both ends of the arm 99. The arm 99 is supported by rolling bearings 10 and can rotate freely. During continuous casting, molten steel is poured into one ladle from the converter, and then the arm 99 rotates 180 degrees to transport the molten steel toward a mold installed on the opposite side of the central axis m. At the same time, the other ladle is positioned next to the converter and molten steel is poured into it. After that, the arm 99 rotates 180 degrees again to transport the molten steel from the other ladle toward the mold. In this way, the two ladles alternately transport molten steel, so that the molten steel from the converter is continuously transported toward the mold.

[0013] The rolling bearing 10 is composed of an annular outer ring 11 and an annular inner ring 12, which are combined with a common central axis via a plurality of balls 13 and 14, which are rolling elements, and the outer ring 11 and the inner ring 12 can rotate relatively around the central axis m. In the following explanation, the direction parallel to the central axis m is referred to as the axial direction, the direction perpendicular to the central axis m as the radial direction, and the direction going around the central axis m as the circumferential direction. In the ladle turret, the rolling bearing 10 is incorporated with the central axis m facing vertically, and the upper vertical direction may be referred to as the first axial direction, and the lower vertical direction may be referred to as the second axial direction.

[0014] See Figure 1. The outer ring 11 is made of a bearing alloy steel such as SNCM. Side surfaces 17 and 18 on both sides in the axial direction are formed in a direction perpendicular to the central axis m and are parallel to each other. An externally toothed gear 19 is formed on the outer periphery of the outer ring 11. The gear 19 meshes with a gear (not shown) of an electric motor, and is driven by the electric motor to rotate the outer ring 11 in the circumferential direction. A first outer raceway surface 21 and a second outer raceway surface 22 are formed on the inner circumference of the outer ring 11 in parallel and facing in opposite axial directions. The first outer raceway surface 21 and the second outer raceway surface 22 are surfaces on which the balls 13 and 14 roll, respectively, and have an arc-shaped axial cross section. The radius of curvature of the second outer raceway surface 22 is larger than the radius of curvature of the first outer raceway surface 21. The first outer raceway surface 21 is formed on one side of the second outer raceway surface 22 in the axial direction. The first outer raceway surface 21 is formed at a position spaced apart from one axial side surface 17 (second side surface) of the outer ring 11 in the other axial direction, and a seal sliding surface 23 is formed between the first outer raceway surface 21 and the side surface 17. The seal sliding surface 23 is a cylindrical surface extending in the axial direction centered on the central axis m, connected to the inner circumferential end of the side surface 17, extending to the other axial direction, and connected to the outer circumferential end of the first outer raceway surface 21. The inner circumferential end of the first outer raceway surface 21 and the inner circumferential end of the second outer raceway surface 22 are connected by an inner circumferential surface 24 that extends parallel to the central axis m. A second seal retaining groove 31 that holds the second seal member 28 is formed in the seal sliding surface 23, and a third seal retaining groove 32 that holds the third seal member 29 is formed in the other axial side surface 18 of the outer ring 11.

[0015] The inner ring 12 is divided in the axial direction into a first inner ring 12a and a second inner ring 12b. The first inner ring 12a and the second inner ring 12b are each made of carbon steel for bearings, such as SNCM. The first inner ring 12a disposed on one side in the axial direction will now be described. A first back surface 34a (first side surface) on one side in the axial direction of the first inner ring 12a and a first front surface 35a on the other side in the axial direction are formed in directions perpendicular to the central axis m and parallel to each other. The first back surface 34a has a larger diameter than the first front surface 35a. Furthermore, both the outer peripheral surface (first outer peripheral surface 36a) and the inner peripheral surface (first inner peripheral surface 37a) are cylindrical surfaces centered on the central axis m. A first inner raceway surface 39a having an arc-shaped axial cross section is formed between the first outer peripheral surface 36a and the first front surface 35a. A protrusion 40 that protrudes in the axial direction over the entire circumference is formed at the corner where the first front surface 35a and the first inner peripheral surface 37a are connected.

[0016] 2 is a front view of the single first inner ring 12a as viewed in the axial direction from the first back surface 34a side, and FIG. 3 is an axial cross-sectional view taken along line AA in FIG. The first back surface 34a is formed with a first seal retaining groove 30 that retains the first seal member 27, and a shield retaining groove 46 into which the shield member 43 is fitted. The first seal retaining groove 30 and the shield retaining groove 46 are each annular and centered on the central axis m, and are formed concentrically with each other. The shield retaining groove 46 is formed radially inward of the first seal retaining groove 30. The first seal retaining groove 30 is a groove recessed in the axial direction from the first back surface 34a along its entire circumference and has a generally rectangular cross section. The shield retaining groove 46 is recessed in the axial direction from the first back surface 34a along its entire circumference and is defined by a groove bottom surface 46a parallel to the first back surface 34a, an outer wall surface 46b axially connecting the radially outer end of the groove bottom surface 46a to the first back surface 34a, and an inner wall surface 46c axially connecting the radially inner end of the groove bottom surface 46a to the first back surface 34a. The outer wall surface 46b and the inner wall surface 46c are both cylindrical surfaces centered on the central axis m.

[0017] Six sets of first screw holes 47, each formed with a pair of female threads, are formed in the first rear surface 34a radially inward of the shield holding groove 46 and spaced equally apart in the circumferential direction. A second screw hole 48 is provided in the center of adjacent first screw holes 47, 47 in the circumferential direction. The first screw hole 47 and the second screw hole 48 are used to secure the shielding member 49 and the shielding member 43, respectively. The shapes and uses of the shielding member 43, the shielding member 49, and the screw holes will be described later.

[0018] The second inner ring 12b on the other axial direction will be described with reference to Figure 1. The side surfaces on both axial sides of the second inner ring 12b are formed in a direction perpendicular to the central axis m and are parallel to each other. The second back surface 34b, which is the side surface on the other axial side, has a larger diameter than the second front surface 35b, which is the side surface on one axial side. Furthermore, the outer peripheral surface (second outer peripheral surface 36b) and the inner peripheral surface (second inner peripheral surface 37b) are both cylindrical surfaces centered on the central axis m. A second inner raceway surface 39b having an arc-shaped axial cross section is formed between the second outer peripheral surface 36b and the second front surface 35b. The radius of curvature of the second inner raceway surface 39b is larger than the radius of curvature of the first inner raceway surface 39a. In addition, a recess 41 recessed in the axial direction is formed over the entire circumference at the corner where the second front surface 35b and the second inner peripheral surface 37b are connected. The first inner ring 12a and the second inner ring 12b are assembled together by fitting the recessed portion 41 and the protruding portion 40 in the axial direction with the first front surface 35a and the second front surface 35b in contact with each other, and by aligning the central axes with each other. After that, bolts (not shown) are inserted through the bolt holes 20, and the rings are firmly assembled together.

[0019] A first bearing is formed by a plurality of first balls 13 arranged in a row in the circumferential direction between the first outer raceway surface 21 and the first inner raceway surface 39a. A second bearing is formed by a plurality of second balls 14 arranged in a row in the circumferential direction between the second outer raceway surface 22 and the second inner raceway surface 39b. The diameter of the second balls 14 is larger than the diameter of the first balls 13. The number of balls 13, 14 in each row is approximately 200. Furthermore, to prevent the balls 13, 14 in each row from coming into direct contact with each other, separators 42 made of steel or resin are installed between adjacent balls 13, 13 (or balls 14, 14) in the circumferential direction. Although not shown, separator 42 has a roughly cylindrical shape and is installed with its central axis aligned in the direction connecting adjacent balls 13, 13 (or balls 14, 14), and the surface that comes into contact with balls 13, 14 is a spherical concave surface with the same curvature as the surface of each ball 13, 14.

[0020] In this way, the outer ring 11 and the inner ring 12 can rotate relatively around the central axis m. In the rolling bearing 10, the raceway surfaces 21, 39a of the first bearing and the raceway surfaces 22, 39b of the second bearing face each other at an angle θ with respect to the central axis m (see FIG. 1), and the first bearing and the second bearing can support loads acting in the axial and radial directions, respectively. In the rolling bearing 10, one axial side surface 17 of the outer ring 11 is positioned at a position shifted in one axial direction from the first back surface 34a of the first inner ring 12a. Also, the first outer peripheral surface 36a of the first inner ring 12a faces the seal sliding surface 23 of the outer ring 11 in the radial direction with a small gap between them.

[0021] When the rolling bearing 10 is assembled to the ladle turret, as shown in Fig. 1, the second back surface 34b of the second inner ring 12b is mounted on a base 98 of the ladle turret, and an arm 99 of the ladle turret is fixed to the outer ring 11. Because the rolling bearing 10 is assembled with its central axis m oriented vertically, the arm 99 can rotate within a horizontal plane. The weight of the arm 99 and the weight of the molten steel being transported act vertically downward on the rolling bearing 10, and these axial loads are supported by the second bearing. In addition, an unbalanced load acts on the arm 99 of the ladle turret when molten steel is poured into and discharged from the ladle. This unbalanced load is supported by the first bearing.

[0022] Next, we will explain the protective member that prevents foreign matter such as scale from entering the raceway surfaces of the rolling bearing 10. Figure 4 is an enlarged partial cross-sectional view showing the area in which the protective member is installed in Figure 1. The protective member includes a first seal member 27 and a shield 50 that are installed on the first back surface 34a of the first bearing, and a second seal member 28 that is installed on the seal sliding surface 23 of the outer ring 11.

[0023] The first seal member 27 is made of rubber and is manufactured by vulcanization molding a rubber material such as nitrile butadiene rubber. The first seal member 27 has a retaining portion 27a that protrudes toward the other axial direction and a lip portion 27b that slopes radially outward as it extends axially upward. The axial cross section of the first seal retaining groove 30 is generally rectangular and slightly smaller than the axial cross section of the retaining portion 27a. The first seal member 27 is formed like a string with a uniform cross section in the longitudinal direction, and is assembled by sequentially pushing the retaining portion 27a into the first seal retaining groove 30 starting from the starting end. After the entire circumference is assembled, the first seal member 27 is cut where it overlaps with the starting end, and the starting end and the terminal end are glued together to assemble the first seal member 27. The tip of lip portion 27b is pressed against seal sliding surface 23 with a predetermined elastic force, preventing foreign matter from entering the interior of rolling bearing 10 through the gap between outer ring 11 and inner ring 12. "Inside" refers to the area in the annular space surrounded by outer ring 11 and inner ring 12 where balls 13, 14 are installed.

[0024] The shield 50 includes six shield members 43 and six shielding members 49. In the rolling bearing 10 of the first embodiment, the six shield members 43 are arranged in an annular shape as a whole around the central axis m, and one shielding member 49 is attached to each of the connecting portions s of the shield members 43 that are adjacent in the circumferential direction.

[0025] FIG. 5 is a perspective view showing the configuration of a single shield member 43. As shown in FIG. The shield member 43 is manufactured by cutting low-carbon steel. The shield member 43 has a first extension portion 44 and a second extension portion 45 that are connected to each other at approximately right angles, and has an L-shaped cross section perpendicular to the longitudinal direction. The cross-sectional shape is uniform in the longitudinal direction. The first extension portion 44 has a rectangular flat plate shape when viewed from the radial direction, and curves in the direction of the plate thickness as it progresses in the longitudinal direction. The second extension portion 45 extends from the other axial end, which is the long side of the first extension portion 44, toward the center of curvature (in a direction away from the outer ring 11).

[0026] The curvature of the outer peripheral surface 44a of the first extension portion 44 is equal to the curvature of the outer wall surface 46b of the shield holding groove 46. The radial width dimension w1 of the second extension portion 45 is slightly smaller than the radial width dimension w0 of the shield holding groove 46. In addition, the thickness t1 (see FIG. 5) of the second extension portion 45 is set slightly larger than the depth h (see FIG. 3) of the shield holding groove 46.

[0027] FIG. 6 is a partial perspective view showing the state in which the shielding member 49 is assembled. The shielding member 49 is manufactured by cutting low-carbon steel material. The shielding member 49 has a third extension portion 51 and a fourth extension portion 52 connected in directions perpendicular to each other, and has an L-shaped cross section perpendicular to the longitudinal direction. The third extension portion 51 has a rectangular shape when viewed from the radial direction, and the outer peripheral surface 51 a curves in the thickness direction as it extends in the longitudinal direction. The curvature of the outer peripheral surface 51 a of the third extension portion 51 is the same as the curvature of the inner peripheral surface 44 b of the first extension portion 44, allowing the shielding member 49 to be assembled in close contact with the inner peripheral surface 44 b of the shield member 43. The fourth extension portion 52 extends toward the center of curvature (away from the outer ring 11) from the other axial end portion, which is the long side of the third extension portion 51. The fourth extension portion 52 has bolt insertion holes formed in two locations that penetrate through the plate thickness direction.

[0028] The shielding member 49 is assembled to the first inner ring 12a so that it is in radial contact with the first extension portion 44 of the shielding member 43 at a position that circumferentially straddles the connecting portion s (see Figure 6) between circumferentially adjacent shielding members 43, and so that the other axial surface on the outer circumferential side of the fourth extension portion 52 overlaps with the second extension portion 45 in the axial direction.

[0029] Similarly, when the shielding members 49 are fixed to all of the connecting portions s, the six shielding members 43 are held in a ring shape centered on the central axis m as a whole. Note that the inner peripheral surface 51b of the third extending portion 51 may be formed as a curved surface that curves along the outer peripheral surface 51a, or may be formed as a flat surface.

[0030] The second seal member 28 will be described with reference to FIG. The second seal member 28 is installed on the seal sliding surface 23 of the outer ring 11. Like the first seal member 27, the second seal member 28 is made of rubber and is manufactured by vulcanization molding of a rubber material such as nitrile butadiene rubber. The second seal member 28 has a retaining portion 28a that protrudes radially outward and a lip portion 28b that inclines toward the other axial direction as it extends radially inward. Similar to the first seal member 27, the second seal member 28 is fixed to the outer ring 11 by pressing the retaining portion 28a into the second seal retaining groove 31. The second seal member 28 is disposed on one side of the axial direction of the first seal member 27 so as to cover the lip portion 27b of the first seal member 27 around the entire circumference, preventing scale and the like from being scattered directly toward the first seal member 27.

[0031] Grease G is filled in the space K radially sandwiched between the seal sliding surface 23 and the shield 50. The grease G is filled to a level that does not exceed the height of the shield 50 (the level shown by the two-dot chain line in FIG. 4). Grease G with a consistency of approximately 265 to 355 (for example, Albania EP2 manufactured by Showa Shell Sekiyu K.K. or EmaLube L manufactured by Kyodo Yushi K.K.) is preferably used, but a grease equivalent to the grease sealed in the rolling bearing 10 may also be used. As shown in Fig. 1, in the rolling bearing 10, a grease supply passage 53 is formed in the first inner ring 12a. The grease supply passages 53 are formed at multiple locations in the circumferential direction, and each opens into the first inner circumferential surface 37a of the first inner ring 12a and into the first back surface 34a between the first seal member 27 and the shield 50. This allows grease G to be supplied from the inner periphery of the first inner ring 12a to the space K, covering the first seal member 27 with grease G. The injected grease G is dispersed evenly in the circumferential direction as the outer ring 11 rotates. By covering the first seal member 27 with the grease G in this manner, scale and the like can be prevented from being scattered directly onto the lip portion 27b of the first seal member 27.

[0032] The assembly procedure and effects of the shield 50 will now be described. As described above, in the rolling bearing 10, the six shield members 43 are assembled into the shield holding groove 46 and are arranged as a whole in an annular shape centered on the central axis.

[0033] The rolling bearing 10 further includes a shield fixing member 54. Figure 7 is an axial cross-sectional view at the position of the second screw hole 48, and is an explanatory diagram illustrating the configuration of the shield fixing member 54. The shield fixing member 54 is made up of a bolt 54a that screws into the second screw hole 48, and a plain washer 54b. By using the shield fixing member 54 when assembling the shield member 43 into the shield holding groove 46, the assembly work of the shield member 43 can be made even easier.

[0034] A circular plain washer 54b is fitted around the neck of the bolt 54a. The second screw hole 48 is arranged so that when the bolt 54a is screwed into it, at least a portion of the outer periphery of the plain washer 54b axially overlaps with the second extension portion 45 of the shield member 43. Because the thickness t1 of the second extension portion 45 is greater than the depth h of the shield retaining groove 46, when the bolt 54a is tightened, the second extension portion 45 is axially sandwiched between the groove bottom surface 46a and the plain washer 54b, thereby fixing the shield member 43 to the first inner ring 12a.

[0035] In this way, by using second screw hole 48, shield member 43 can be fixed simply by tightening one bolt 54a, which facilitates the task of arranging multiple shield members 43 along shield holding groove 46. For example, even if the sizes of the gaps at connecting portions s are uneven when all shield members 43 are attached, the positions of shield members 43 can be easily shifted simply by loosening bolt 54a, making it easy to adjust the sizes of the gaps to be uniform. The shield members 43 are assembled such that the circumferential positions of the connecting portions s of the adjacent shield members 43 coincide with the circumferential positions of the first screw holes 47.

[0036] After the shielding member 43 is positioned along the shield holding groove 46, the shielding member 49 is assembled as shown in Fig. 6. The shielding member 49 is assembled to the first inner ring 12a so that it comes into radial contact with the first extending portion 44 of the shielding member 43 at a position that circumferentially straddles the connecting portion s between circumferentially adjacent shielding members 43, and so that the other axial surface on the outer circumferential side of the fourth extending portion 52 overlaps with the second extending portion 45 in the axial direction. Since the thickness t1 of the second extension portion 45 is greater than the depth h of the shield holding groove 46, by aligning the bolt insertion hole of the fourth extension portion 52 with the first screw hole 47 and tightening the bolt 25, the second extension portion 45 is clamped in the axial direction between the shielding member 49 and the groove bottom surface 46a, and the shielding member 43 is held immovable relative to the first inner ring 12a.

[0037] When assembling the shielding member 49, it is preferable to assemble it while pressing it radially outward against the shielding member 43. By doing so, the outer peripheral surface 44a of the shielding member 43 is disposed along the outer wall surface 46b of the shield holding groove 46, so that the multiple shielding members 43 can be aligned in an annular shape. Furthermore, since the inner peripheral surface 44b of the first extending portion 44 of the shielding member 43 and the outer peripheral surface 51a of the third extending portion 51 of the shielding member 49 are formed with the same curvature, the shielding member 49 can be assembled so that the outer peripheral surface 51a of the shielding member 49 and the inner peripheral surface 44b of the shielding member 43 are in close contact with each other.

[0038] Similarly, when the shielding members 49 are fixed to all the connecting portions s, the six shielding members 43 are held in an annular shape centered on the central axis m.

[0039] The shielding member 49 is assembled so as to straddle the connecting portion s of the shielding member 43 in the circumferential direction, and therefore the first extending portion 44 of the shielding member 43 and the third extending portion 51 of the shielding member 49 are assembled so as to overlap radially on both circumferential sides of the connecting portion s. This prevents the grease G from passing through the joint between the first extending portion 44 and the third extending portion 51, thereby reliably preventing the grease G filled in the space K between the seal sliding surface 23 of the outer ring 11 and the shield 50 from leaking out through the connecting portion s of the shielding member 43.

[0040] In this way, in the rolling bearing 10 of the first embodiment, it is not necessary to weld the shield members 43, and therefore it is not necessary to combine the shield members 43 so that they come into contact with each other at the joint portions s. When sealing the joints s of the shielding members 43 by welding them together, as in the conventional method, the shielding members 43 need to be assembled so that they contact each other in the circumferential direction. If the longitudinal length of each shielding member 43 were shorter than necessary, assembling multiple shielding members 43 in succession while bringing them into close contact would result in a large gap between the first and last assembled shielding members 43, making welding impossible. Conversely, if the longitudinal length of each shielding member 43 were longer than necessary, it would be necessary to trim the last assembled shielding member 43 to adjust its circumferential length.

[0041] In contrast, with the shield 50 of this embodiment, even if the gap at the connecting portion s becomes large to some extent, the gap can be blocked by the shielding member 49, preventing leakage of the grease G. This eliminates the need for welding work that requires special skills, and simplifies assembly of the shield 50 because variations in the length of the shield member 43 are tolerated. This allows for a significant reduction in the number of steps required to assemble an extra-large bearing.

[0042] As can be seen from the above explanation, in the rolling bearing 10 of this embodiment, by incorporating the shield 50 that protrudes axially from the first back surface 34a of the inner ring 12 and is arranged in an annular shape centered on the central axis m, it is possible to effectively prevent foreign matter from entering the interior of an extra-large bearing used in harsh environments such as steelmaking equipment. Use of the present invention can simplify the assembly work of the shield 50, thereby reducing the number of steps required to assemble the rolling bearing 10, which is an extra-large bearing.

[0043] 1, in the rolling bearing 10, a third seal member 29 is installed on the other axial side surface 18 of the outer ring 11 to prevent foreign matter from entering the interior of the bearing from the other axial direction. The third seal member 29 has a similar configuration to the first seal member 27, and differs only in that the lip portion is inclined radially inward as it extends axially downward, so a description of it will be omitted.

[0044] (Second embodiment) A second embodiment of the present invention will now be described. Figure 8 is an axial cross-sectional view of a second rolling bearing 60 according to the second embodiment of the present invention. The rolling bearing 60 differs from the rolling bearing 10 of the first embodiment in that a shield 50 is provided on the outer ring 11. Since the configuration of the raceway surfaces and the like is the same as that of the rolling bearing of the first embodiment, the same names and numbers are used for common components, and a brief description will be given or omitted.

[0045] In the rolling bearing 60, similarly to the rolling bearing 10 of the first embodiment, the inner ring 12 is divided in the axial direction, and a first inner ring 12a and a second inner ring 12b are combined together. A first back surface 34a (second side surface) of the first inner ring 12a is disposed at a position shifted in one axial direction from a side surface 17 (first side surface) on one axial side of the outer ring 11.

[0046] 9 is an enlarged partial cross-sectional view of a rolling bearing 60 showing an area where a protective member that prevents the intrusion of foreign matter is incorporated. The protective member includes a first seal member 27 and a shield 50 installed on one axial side surface 17 of the outer ring 11, and a second seal member 28 installed on the outer peripheral surface of the first inner ring 12a. A second seal retaining groove that holds the second seal member 28 is formed in the outer peripheral surface 68 of the first inner ring 12a. The first seal member 27 and the second seal member 28 differ from the first seal member 27 and the second seal member 28 of the first embodiment only in the extending direction of the lips, and therefore will not be described here.

[0047] A first seal retaining groove 30 that retains the first seal member 27 and a shield retaining groove 64 into which the shield member 61 is fitted are formed on one axial side surface 17 of the outer ring 11. The first seal retaining groove 30 and the shield retaining groove 64 are each annular and centered on the central axis m, and are formed concentrically with each other, with the shield retaining groove 64 being formed radially outward of the first seal retaining groove 30.

[0048] The first seal retaining groove 30 is a groove recessed in the axial direction from the side surface 17 over the entire periphery, and has a substantially rectangular cross section. The shield holding groove 64 is recessed in the axial direction from the side surface 17 along its entire circumference, and is defined by a groove bottom surface 64a parallel to the side surface 17, an outer wall surface 64b axially connecting the radially outer end of the groove bottom surface 64a to the side surface 17, and an inner wall surface 64c axially connecting the radially inner end of the groove bottom surface 64a to the side surface 17. Both the outer wall surface 64b and the inner wall surface 64c are cylindrical surfaces centered on the central axis m. Furthermore, a first screw hole 47 is formed on the side surface 17 radially outward of the shield holding groove 64 .

[0049] Although not shown in the drawings, the shield 50 includes a plurality of shield members 61 arranged in a ring shape in the circumferential direction, as in the first embodiment, and a plurality of shielding members 65. The plurality of shielding members 61 are arranged in a ring shape centered on the central axis m as a whole, and one shielding member 65 is assembled to each of the connecting portions s of the shielding members 61 adjacent to each other in the circumferential direction.

[0050] The shield member 61 has a first extension portion 62 and a second extension portion 63 that are connected to each other at approximately right angles, and has an L-shaped cross section perpendicular to the longitudinal direction. The cross-sectional shape is uniform in the longitudinal direction. The first extension portion 62 has a rectangular flat plate shape when viewed from the radial direction, and curves in the direction of its thickness as it progresses in the longitudinal direction. The second extension portion 63 extends from the other axial end portion, which is the long side of the first extension portion 62, to the side opposite the center of curvature (the side away from the first inner ring 12a). The curvature of the inner peripheral surface of the first extending portion 62 is equal to the curvature of the inner wall surface 64c of the shield holding groove 64. Furthermore, the width dimension w1 of the second extending portion 63 is slightly smaller than the radial width dimension w0 of the shield holding groove 64. This allows the shield members 61 to be installed side by side in the circumferential direction along the shield holding groove 64, with the second extending portions 63 accommodated in the shield holding groove 64.

[0051] The shielding member 65 has a third extending portion 66 and a fourth extending portion 67 connected in directions perpendicular to each other, and has an L-shaped cross section in a direction perpendicular to the longitudinal direction. The third extension portion 66 has a rectangular shape when viewed from the radial direction, and an inner circumferential surface 66b curves in the thickness direction as it extends in the longitudinal direction. The curvature of the inner circumferential surface 66b of the third extension portion 66 is equal to the curvature of the outer circumferential surface 62a of the first extension portion 62, so that the inner circumferential surface 66b of the shielding member 65 is in close contact with the outer circumferential surface 62a of the shielding member 61. The fourth extension portion 67 extends from the other axial end portion, which is the long side of the third extension portion 66, to the side opposite the center of curvature (the side away from the first inner ring 12a). A bolt hole is formed in the fourth extension portion 67, penetrating it in the plate thickness direction. The shielding member 65 can be fixed to the outer ring 11 by aligning the bolt hole with the position of the first screw hole 47 and tightening the bolt 25.

[0052] 9, after the shielding member 61 is positioned along the shield holding groove 64, the shielding member 65 is fixed to the outer ring 11 at a position overlapping with the second extending portion 63 in the axial direction. The thickness t1 of the second extending portion 63 of the shielding member 61 is set to be slightly larger than the depth h of the shield holding groove 64. Therefore, when the bolt 25 is tightened, the second extending portion 63 is sandwiched in the axial direction between the shielding member 65 and the groove bottom surface 64a, and the shielding member 61 is held immovably relative to the first inner ring 12a. In addition, a second screw hole 48 (not shown) is provided at the circumferential center of each first screw hole 47, and the circumferential position of the shield member 61 can be easily adjusted in the same way as in the first embodiment.

[0053] Thus, in the rolling bearing 60 of the second embodiment, when the shielding members 65 are fixed to all of the connecting portions s of the shielding members 61, the multiple shielding members 61 protrude in one axial direction from the axial side surface 17 of the outer ring 11 and are held in a ring shape centered on the central axis m.

[0054] Grease G is filled in a space K radially sandwiched between the outer peripheral surface 68 of the first inner ring 12a and the shield 50. As shown by the two-dot chain line in FIG. 9, the grease G is filled to a level that does not exceed the height of the shield 50.

[0055] As with the first embodiment, in the shield 50 of the second embodiment, even if the gap at the connecting portion s becomes large to some extent, the gap can be blocked by the shielding member 65, preventing leakage of the grease G. This eliminates the need for welding work that requires special skills, and simplifies the assembly of the shield 50 because variations in the length of the shield member 43 are tolerated. This significantly reduces the number of steps required to assemble the extra-large bearing, thereby reducing the number of steps required to assemble the rolling bearing 60, which is an extra-large bearing.

[0056] As a modified example of the shield assembly state, as shown in Fig. 10, the shield 50, which is disposed annularly in the same manner as in the first embodiment, can be disposed close to the outer ring 11. By disposing it in this manner, a labyrinth is formed between the outer ring 11 and the shield 50, making it possible to prevent the intrusion of foreign matter. 10 shows an example in which the shield 50 is mounted on one axial side of the rolling bearing, but it may also be mounted on the other axial side. Although not shown, for example, it may be mounted in the position of the third seal member of the rolling bearing of the first embodiment. In this case, the shield 50 is mounted on the side surface 18 on the other axial side of the outer ring 11, and a labyrinth is formed between the shield 50 and the second outer peripheral surface 36b of the second inner ring 12b.

[0057] Although the embodiments of the present invention have been described above, the above-described embodiments are merely examples for carrying out the present invention. The present invention is not limited to the above-described embodiments, and can be carried out by appropriately modifying the above-described embodiments within the scope of the spirit of the present invention. For example, in the above embodiment, an angular rolling bearing in which the rolling elements are balls has been described, but the type of bearing is not limited to this. The rolling elements may be cylindrical rollers or spherical rollers, and the present invention may be applied to radial bearings or thrust bearings. [Explanation of symbols]

[0058] (First embodiment) 10: rolling bearing, 11: outer ring, 12: inner ring, 12a: first inner ring, 12b: second inner ring, 13: ball, 14: ball, 17: side surface (one side of outer ring), 18: side surface (other side of outer ring), 19: gear, 21: first outer raceway surface, 22: second outer raceway surface, 23: seal sliding surface, 24: inner peripheral surface, 27: first seal member, 28: second seal member, 29: third seal member, 30: first seal retaining groove, 31: second seal retaining groove, 32: third seal retaining groove, 34a: first back surface, 34b: second back surface, 35a: 1st front surface, 35b: 2nd front surface, 36a: 1st outer peripheral surface, 36b: 2nd outer peripheral surface, 37a: 1st inner peripheral surface, 37b: 2nd inner peripheral surface, 39a: 1st inner raceway surface, 39b: 2nd inner raceway surface, 42: Separator, 43: Shield member, 44: 1st extension part, 45: Second extension part, 46: Shield holding groove, 47: First screw hole, 48: Second screw hole, 49: Shielding member, 50: Shield, 51: Third extension part, 52: Fourth extension part, 53: Grease supply passage, 54: Shield fixing member, 54a: Bolt, 54b: Plain washer, (Second embodiment) 60: second rolling bearing, 61: shield member, 62: first extension part, 63: second extension part, 64: shield holding groove, 65: shielding member, 66: third extension part, 67: fourth extension part, (Prior art) 90: Rolling bearing, 91: Inner ring, 92: Outer ring, 93: Sealing member, 94: Shield, 94a: Shielding member, 98: Stand, 99: Arm

Claims

1. an inner ring having an inner raceway surface on its outer periphery; an outer ring having an outer raceway surface on its inner periphery; a plurality of rolling elements rollably disposed between the inner raceway surface and the outer raceway surface; a shield to prevent the intrusion of foreign matter; A rolling bearing in which the outer ring and the inner ring rotate relatively around a central axis, one of the inner ring and the outer ring has a first side surface on one side in the axial direction; the other of the inner ring and the outer ring has a second side surface located on one side in the axial direction further toward the one side in the axial direction than the first side surface, the shield is installed on the first side surface, and is arranged in a ring shape centered on the central axis by connecting a plurality of shielding members with a plurality of shielding members as a whole, and faces the other of the inner ring and the outer ring in the radial direction, A rolling bearing characterized in that the multiple shielding members are arranged across the connecting portions of the shielding members that are adjacent to each other in the circumferential direction, and are assembled so as to overlap the shielding members in the radial direction on both sides of the connecting portions.

2. the first side surface has an annular groove centered on the central axis and recessed toward the other axial direction, the shield member has a first extending portion extending in an axial direction, and a second extending portion connected to one end of the first extending portion and extending in a radial direction in a direction away from the other of the inner ring and the outer ring, the shielding member has a third extending portion extending in an axial direction, and a fourth extending portion connected to one end of the third extending portion and extending in a radial direction in a direction away from the other of the inner ring and the outer ring, The plurality of shield members are arranged in an annular shape as a whole with the second extension portions fitted into the grooves, 2. The rolling bearing according to claim 1, wherein the shielding member is assembled such that the first extension and the third extension overlap in the radial direction on both sides of the connecting portion.

3. 3. The rolling bearing according to claim 2, wherein the shielding member is disposed axially to one side of the second extending portion, and is fixed to one of the inner ring and the outer ring at a position where at least a portion of the shielding member overlaps with the second extending portion in the axial direction.

4. 4. A rolling bearing according to claim 2, further comprising a shield fixing member fixed to one of the inner ring and the outer ring at a circumferentially different position from the shielding member so that at least a portion of the shield fixing member overlaps with the second extension portion in the axial direction.

5. 5. A rolling bearing according to claim 1, further comprising a rubber sealing member that is located in an area radially sandwiched between the shield and the other of the inner ring and the outer ring, that is fixed to one of the inner ring and the outer ring, and that comes into sliding contact with the other of the inner ring and the outer ring, thereby filling a gap between the outer ring and the inner ring.

6. 6. The rolling bearing according to claim 5, wherein a space radially surrounded by the shield and the other of the inner ring and the outer ring is filled with grease, and the seal member is covered with the grease.

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