Self-aligning roller bearing

Abstract

To provide a self-aligning roller bearing that has a long lifetime and generates less heat.SOLUTION: When a distance obtained by subtracting a maximum diameter DW of a roller 50 from a distance along a pitch circle PC between inner side faces 42 of circumferentially adjacent column parts 42 is defined as a pocket gap C, a pocket gap ratio C / DW obtained by dividing the pocket gap C by the maximum diameter DW of the roller 50 is larger than 0.005 and less than 0.01 (0.005<C / DW<0.01), and when a curvature radius in an axial direction of an outer ring raceway surface 31 is defined as rout, a curvature radius in an axial direction of an inner ring raceway surface 21 is defined as rin, and a curvature radius in an axial direction of a rolling surface 51 of the roller 50 is defined as rc, an outer ring grip rate rc / rout and an inner ring grip rate rc / rin are each 94% or more and 98% or less.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a self-aligning roller bearing.

Background Art

[0002] A self-aligning roller bearing, which is a type of rolling bearing, has self-aligning properties because the center of curvature of the outer ring raceway surface coincides with the bearing center. It can be used even when inclination occurs between the outer ring and the inner ring due to factors such as the machining of the housing and the deflection of the shaft caused by the load. For this reason, self-aligning roller bearings are widely used as bearings for various industrial machines such as paper-making machines, steel rolling mills, and construction machinery.

[0003] In recent years, in mechanical devices using self-aligning roller bearings, there has been an increasing demand in the industrial world to extend the life of such mechanical devices, and there is also a strong demand for extending the life of self-aligning roller bearings.

[0004] Patent Document 1 discloses a low-heat-generating self-aligning roller bearing in which the surface roughness of the inner ring raceway surface < the surface roughness of the outer ring raceway surface, and the inner ring holding ratio rc / rin is made smaller than the outer ring holding ratio rc / rout (rc / rin < rc / rout), thereby suppressing skew.

[0005] Further, Patent Document 2 discloses a self-aligning roller bearing for an elevator hoisting machine with a long life by reducing the amount of heat generation by making both the outer ring holding ratio rc / rout and the inner ring holding ratio rc / rin satisfy 0.94 or more and 0.98 or less.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] However, the self-aligning roller bearings described in Patent Documents 1 and 2 only take into consideration the outer ring contact ratio rc / rout and the inner ring contact ratio rc / rin, and depending on the specifications of the cage, a sufficient life may not be obtained, so further improvements were required.

[0008] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a self-aligning roller bearing which has a long life and generates little heat. [Means for solving the problem]

[0009] Therefore, the above object of the present invention is achieved by the following configuration [1] of a self-aligning roller bearing. [1] An outer ring having an outer ring raceway surface on its inner peripheral surface, an inner ring having an inner ring raceway surface on its outer peripheral surface, a plurality of rollers arranged between the outer ring raceway surface and the inner ring raceway surface and having rolling surfaces that roll on the inner ring raceway surface and the outer ring raceway surface, and a cage having pockets formed between a plurality of pillars extending in the axial direction and spaced apart in the circumferential direction, and capable of rotatably holding each of the plurality of rollers; A self-aligning roller bearing comprising: If a circle that is centered on the central axis of the outer ring and the inner ring and passes through the axis of the roller is defined as a pitch circle, When the distance between the inner surfaces of the column portions adjacent in the circumferential direction along the pitch circle minus the maximum diameter of the roller is defined as a pocket gap C, the pocket gap C divided by the maximum diameter DW of the roller is a pocket gap ratio C / DW that is greater than 0.005 and less than 0.01 (0.005 <C / DW<0.01)、 Furthermore, when the radius of curvature of the outer ring raceway surface in the axial direction is rout, the radius of curvature of the inner ring raceway surface in the axial direction is rin, and the radius of curvature of the rolling surface of the roller in the axial direction is rc, the outer ring contact ratio rc / rout and the inner ring contact ratio rc / rin are 94% or more and 98% or less, respectively. Spherical roller bearing. Effect of the Invention

[0010] According to the present invention, a self-aligning roller bearing having a long life and generating little heat can be obtained. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a sectional perspective view of a self-aligning roller bearing according to the present invention. [Diagram 2] FIG. 2 is a cross-sectional view of a main portion of the self-aligning roller bearing of FIG. [Diagram 3] FIG. 3 is a schematic view of a part of the cage as viewed from the outer periphery side. [Figure 4] FIG. 4 is an enlarged view of the roller. [Diagram 5] FIG. 5(a) is a side view showing the positional relationship between the cage and rollers of the self-aligning roller bearing of FIG. 1, and FIG. 5(b) is an enlarged view of a main portion of FIG. 5(a). [Figure 6] FIG. 6 is a schematic cross-sectional view showing the relationship between the cage and the rollers. [Figure 7] FIG. 7 is a schematic cross-sectional view showing the relationship between the cage and roller clearances of another type. [Figure 8] FIG. 8 is a graph showing the relationship between the pocket gap ratio and the life ratio in Example 1. [Figure 9] FIG. 9 is a graph showing the relationship between the bearing rotation speed and the outer ring temperature in Example 2. [Figure 10] FIG. 10 is a graph showing the relationship between the bearing rotation speed and the outer ring temperature in Example 4. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a self-aligning roller bearing according to the present invention will now be described in detail with reference to the drawings. As shown in Figures 1 and 2, the self-aligning roller bearing 10 of this embodiment has an inner ring 20, an outer ring 30, and a number of spherical rollers 50 (hereinafter sometimes simply referred to as "rollers") arranged in two rows between the inner ring 20 and the outer ring 30 on either side of the axial center line CL and held freely rotatable by a retainer 40.

[0013] The axis C2 of the rollers 50 arranged in two rows is inclined with respect to the central axis C1 of the outer ring 30 and the inner ring 20. Specifically, in Fig. 1, the axis C2 of the rollers 50 arranged on the right side is inclined so as to move radially inward toward the right, and the axis C2 of the rollers 50 arranged on the left side is inclined so as to move radially inward toward the left.

[0014] The inner ring 20 is formed with double-row concave spherical inner ring raceway surfaces 21, 21 so that the central side in the axial direction (left-right direction in Figures 1 and 2) is convex, and a substantially flat top surface 22 is formed in the axial central portion between the two raceway surfaces 21, 21.

[0015] The outer ring 30 has a raceway surface 31 formed in a concave spherical shape along the entire width direction of the inner circumferential surface.

[0016] As shown in Fig. 3, the cage 40 has an annular portion 41 disposed at approximately the center in the axial direction, and a plurality of pillar portions 42 extending axially outward from both axial ends of the annular portion 41. A U-shaped pocket 43 is formed by the inner side surface 42a of each pillar portion 42 adjacent to each other in the circumferential direction and the side surface 41a of the annular portion 41. Rollers 50 are rotatably held in the pocket 43. By independently accommodating each row of rollers 50 in each pocket 43, each roller row is formed on both sides of the annular portion 41, and each roller 50 in each roller row is rotatably held at a fixed interval along the circumferential direction.

[0017] Each pocket 43 of the retainer 40 is formed so as to be shifted by half a pitch in the circumferential direction between each row of rollers, and the rollers 50 in each row are arranged alternately (staggered) in the circumferential direction with the annular portion 41 in between.

[0018] 4, rollers 50 are arranged in two rows between the outer ring raceway surface 31 of the outer ring 30 and each of the inner ring raceway surfaces 21, 21 of the inner ring 20, and are rotatably held by a cage 40. The outer peripheral surface of roller 50 is spherical with a larger diameter at the center, and forms a rolling surface 51 with respect to the inner and outer ring raceway surfaces 21, 21, 31.

[0019] In the self-aligning spherical roller bearing 10, when the inner ring 20 and the outer ring 30 rotate relative to each other, the rollers 50 in the pockets 43 also rotate, so friction and slip occur between the inner ring 20, the outer ring 30, the cage 40 and the rollers 50. Due to this friction and slip, for example, damage such as peeling may occur on the inner ring raceway surface 21 of the inner ring 20 or the outer ring raceway surface 31 of the outer ring 30, or the temperature may become high, resulting in a reduction in the life of the self-aligning spherical roller bearing 10.

[0020] In the self-aligning spherical roller bearing 10 of the present embodiment, the pocket clearance ratio C / DW is more than 0.005 and less than 0.01 (0.005 < C / DW < 0.01), and the outer ring holding ratio rc / rout and the inner ring holding ratio rc / rin are set to 94% or more and 98% or less (94% ≤ rc / rout, rc / rin ≤ 98%), respectively.

[0021] Here, with reference to FIG. 5, the pocket clearance ratio C / DW is the value obtained by dividing the pocket clearance C, which is the distance obtained by subtracting the maximum diameter DW of the roller 50 from the distance along the pitch circle PC between the inner side surfaces 42a of the column portions 42 adjacent in the circumferential direction when a circle passing through the axis center C2 of the roller 50 is defined as the pitch circle PC with the central axis C1 (see FIG. 1) of the outer ring 30 and the inner ring 20 as the center, by the maximum diameter DW of the roller 50.

[0022] Also, with reference to FIGS. 1 and 2, the outer ring holding ratio rc / rout is the value obtained by dividing the curvature radius rout in the axial direction of the outer ring raceway surface 31 by the curvature radius rc in the axial direction of the rolling surface 51 of the roller 50, and the inner ring holding ratio rc / rin is the value obtained by dividing the curvature radius rin in the axial direction of the inner ring raceway surfaces 21, 21 by the curvature radius rc in the axial direction of the rolling surface 51 of the roller 50.

[0023] The reason for setting the pocket clearance ratio C / DW to be more than 0.005 and less than 0.01 (0.005 < C / DW < 0.01) is that when the pocket clearance ratio C / DW is 0.005 or less, abnormal heat generation due to partial metal contact occurs between the cage 40 and the rollers 50, and as a result, the temperature of the inner ring 20 and the outer ring 30 may become too high, affecting the life.

[0024] Also, when the pocket clearance ratio C / DW becomes 0.01 or more, the roller 50 in the pocket 43 is likely to cause a large skew or the like, so the slippage increases at the contact portions between the inner ring 20 and the roller 50 and between the outer ring 30 and the roller 50. In particular, peeling is likely to occur on the inner ring 20 where the surface pressure is geometrically high, which may reduce the life of the self-aligning roller bearing 10.

[0025] Also, the outer ring holding ratio rc / rout and the inner ring holding ratio rc / rin are set to 94% or more and 98% or less (94% ≤ rc / rout, rc / rin ≤ 98%) respectively. When the outer ring holding ratio rc / rout and the inner ring holding ratio rc / rin are less than 94%, the contact area between the raceway surface and the rolling surface of the roller becomes small, so the surface pressure when the self-aligning roller bearing 10 receives a load increases, and there is a risk that the self-aligning roller bearing 10 may be damaged. Also, when the outer ring holding ratio rc / rout and the inner ring holding ratio rc / rin exceed 98%, the heat generation due to slippage increases as the rotational speed of the self-aligning roller bearing 10 increases.

[0026] When a skew occurs in which the roller 50 tilts with respect to the normal rotation axis, sliding contact occurs between the roller 50 and the inner and outer ring raceway surfaces 21, 21, 31, which causes heat generation. Therefore, for the long life of the self-aligning roller bearing 10, it is required to control the traction balance received by the roller 50 from the inner and outer rings 20, 30 and control the skew of the roller 50. For this reason, it is preferable that rc / rin < rc / rout.

[0027] Also, the surface roughness of the outer ring raceway surface 31 and the inner ring raceway surface 21 is processed to 0.13 μm or less by grinding or the like. The surface roughness of the outer ring raceway surface 31 and the inner ring raceway surface 21 is set to 0.13 μm or less in order to suppress heat generation due to friction between the outer ring raceway surface 31 and the inner ring raceway surface 21 and the roller 50 and extend the life.

[0028] Furthermore, by making the surface roughness of outer ring raceway surface 31 greater than that of inner ring raceway surface 21, a positive skew is created in which rollers 50 tilt toward the outside of self-aligning roller bearing 10, thereby reducing thrust (axial) load and extending the lifespan, so it is preferable to make the surface roughness of outer ring raceway surface 31 greater than that of inner ring raceway surface 21.

[0029] [Example] Example 1 In Example 1, the life ratios of spherical roller bearings A, B, and C (hereinafter simply referred to as bearings A, B, and C) were examined. The life ratio is the ratio of the actual life time to the basic rated life of each bearing based on its dynamic load rating. The actual life time is the time when flaking occurs on either the inner ring, outer ring, or rollers. Note that in this example, flaking occurred on the inner ring in all cases.

[0030] Bearings A, B, and C differ only in the pocket clearance ratio C / DW, and other conditions are the same. Specifically, the basic bearing is model number 22211 (outer diameter 100 mm, inner diameter 55 mm, width 25 mm), and the surface roughness and heat treatment of the inner ring, outer ring, and rollers are also the same. The inner ring contact ratio and outer ring contact ratio are set to the same contact ratio (rc / rin=94.0% rc / rou=96.5%) for bearings A, B, and C. The cages for bearings A and C are cages 40 that hold the rollers on the pitch circle PC explained in Figures 1, 2, and 5, and the cage for bearing B is a special cage 45 (see Figure 6) that holds the rollers on the inner diameter side of the pitch circle PC.

[0031] Here, the pocket gap C of the cage 40 and the cage 45 will be described with reference to Fig. 6. Note that the pocket gap C is exaggerated in Fig. 6 for ease of understanding. As shown in Fig. 6, when the point P1 is the radial center of the inner surface 42a of the column portion 42, and the intersection point of the straight line connecting the axis C2 of the roller 50 and point P1 with the outer peripheral surface 51 of the roller 50 is point P2, the pocket gap C of the cage 40 is a distance L10 between point P1 and point P2, which is 1 / 2 of the pocket gap C of the cage 40. In other words, the pocket gap C of the cage 40 is C=2×L10.

[0032] Also, the pocket clearance C of the cage 45 is calculated by the approximate formula shown below. As shown in Fig. 6, the radially inner end of the inner surface 42a of the column portion 42 of the cage 45 is defined as point P3, and the intersection of the straight line connecting the axis C2 of the roller 50 and point P3 and the outer peripheral surface 51 of the roller 50 is defined as point P4. Let the intersection angle of the straight line connecting the axis C2 and point P3 and the straight line connecting the axis C2 and point P1 be θ.

[0033] A straight line passing through point P4 and parallel to the straight line connecting the axis C2 and point P1 and a straight line passing through point P3 and perpendicular to the straight line connecting point P4 and point P3 intersect at point P5. Thus, a right triangle with sides p, q, and r is formed at points P3, P4, and P5. Therefore, the pocket clearance C of the cage 45 is twice the distance L20 (the length of side q) between point P4 and point P5, and the pocket clearance C of the cage 45 can be approximated as C = 2 × L20.

[0034] Here, the distance (the length of side p) between point P3 and point P4 described for the cage 45 is the same as the distance L10 described for the cage 40. Also, since p = q × cosθ and 0 < cosθ < 1, L10 < L20, that is, the pocket clearance C of the cage 40 is shorter than the pocket clearance C of the cage 45.

[0035] Next, the surface roughness of the inner ring, outer ring, and roller of bearings A, B, and C is shown below. A specific description is given. (Roughness condition) Surface roughness of the outer ring: 0.3μm Ra Surface roughness of the inner ring: 0.07μm Ra Surface roughness of the roller: 0.05μm Ra

[0036] The test conditions are as follows. Test radial load: 45200N Test axial load: 0N Inner ring rotational speed: 1500 min -1 (Outer ring fixed) Lubrication method: JX Nippon Oil & Fats FBK Oil RO68, forced supply circulation

[0037] The dynamic load rating (Cr), basic rated life (H), and pocket clearance ratio (C / DW) of each bearing are as follows. The pocket clearance C of bearings A and C is 2×L10, and the pocket clearance C of bearing B is 2×L20 (see Figure 6).

[0038] (Bearing A) Dynamic load rating (Cr): 10400kgf Basic rating life (H): 176 hours Pocket gap ratio (C / DW): 0.0135

[0039] (Bearing B) Dynamic load rating (Cr): 12150kgf Basic rating life (H): 278 hours Pocket gap ratio (C / DW): 0.00866

[0040] (Bearing C) Dynamic load rating (Cr): 11680kgf Basic rating life (H): 245 hours Pocket gap ratio (C / DW): 0.00805

[0041] (Test Results) The inner rings of bearings A, B, and C were rotated until the end of their life, and the relationship between the life ratio and pocket clearance ratio for each bearing was investigated. The results are shown in Fig. 8. As shown in Fig. 8, the life ratio of bearing A was 0.23, the life ratio of bearing B was 1.58, and the life ratio of bearing C was 2.3. Note that points A, B, and C in the figure represent the test results for bearings A, B, and C, respectively.

[0042] If points A, B, and C are connected by an approximation curve, it can be seen that the life ratio decreases as the pocket gap ratio increases. According to this approximation curve, the pocket gap ratio at which the life ratio becomes 1 is 0.99, and the upper limit of the pocket gap ratio is less than 0.01, and preferably less than 0.0099.

[0043] When the pocket gap ratio is large, like bearing A, the life ratio drops significantly, but conversely, when the pocket gap ratio is small, like bearing C, the life ratio increases significantly. Also, bearing B, which has a pocket gap ratio between bearings A and C, showed a life ratio intermediate between bearings A and C. From the above, it was found that the life can be extended by making the pocket gap ratio smaller.

[0044] One of the reasons for this is thought to be that by reducing the pocket gap ratio, the rollers come into contact with the cage, generating frictional force, which in turn reduces the number of rotations of the rollers, thereby reducing the slippage between the rollers and the inner ring, thereby suppressing surface fatigue of the inner ring. A brief explanation is given below.

[0045] As the rollers rotate, they come into contact with the inner ring, outer ring, and cage, generating frictional forces. In particular, the frictional force is greater in the loaded zone (including the entrance and exit of the loaded zone) than in the non-loaded zone. Here, if the pocket clearance ratio is reduced, the rollers and cage (inner surface) come closer together, resulting in stronger contact and temporarily increasing the frictional force, and the number of rotations of the rollers decreases. As a result, the difference in rotational speed (circumferential speed) between the rollers and the inner ring becomes smaller, and the actual life time, which is the time it takes for flaking to occur in the inner ring, becomes longer, which is thought to extend the life ratio.

[0046] Example 2 In Example 2, the effects on heat generation due to differences in pocket clearance, inner ring contact ratio, outer ring contact ratio, and surface roughness of the outer ring raceway surface are examined. Specifically, of spherical roller bearings D, E, and F, bearing F is compared with bearings D and E to examine the suitability of the pocket clearance ratio of bearing F.

[0047] Bearings D, E, and F use model number 24128 bearing (outer diameter 225 mm, inner diameter 140 mm, width 85 mm) as the basic bearing, and retainer 40 (see Figs. 1, 3, and 6) is applied to bearings D and F, while another retainer 47 (two-piece raceway guided press retainer) that retains rollers on the outer diameter side of pitch circle PC shown in Fig. 7 is applied to bearing E. Details are described below. Bearing D has the same design as bearing A in Example 1, bearing E has the same design as bearing B in Example 1, and bearing F has the same design as bearing C in Example 1.

[0048] The inner ring contact ratio and outer ring contact ratio were also set differently. The inner ring contact ratio and outer ring contact ratio were set to (rc / rin = 97.6%, rc / rou = 99.0%) for bearings D and E, and to (rc / rin = 96.7%, rc / rou = 97.6%) for bearing F. The roughness of the outer ring raceway surface was set to a maximum of 0.20 μm for bearing D, a maximum of 0.40 μm for bearing E, and a maximum of 0.10 μm for bearing F. Meanwhile, the surface roughness of the inner ring raceway surface for bearings D and F was set to a maximum of 0.13 μm for bearings D and F, and a maximum of 0.08 μm for bearing E, and the surface roughness of the rollers was set to a maximum of 0.07 μm for bearings D, E, and F.

[0049] The test conditions are as follows. Test radial load: 75700N Test axial load: 0N Inner wheel rotation speed: 1300 min -1 , 1950min -1 , 2600min -1 , 3250min -1 (Bearing F only) Lubrication method: JX Nippon Oil & Gas FBK Oil VG68, forced supply circulation

[0050] The dynamic load rating (Cr), basic static radial load rating (COr), and pocket clearance ratio (C / DW) of each bearing are as follows.

[0051] (Bearing D) Dynamic load rating (Cr): 835kN Basic static radial load rating (COr): 1160kN Pocket gap ratio (C / DW): 0.0163

[0052] (Bearing E) Dynamic load rating (Cr): 796kN Basic static radial load rating (COr): 1160kN Pocket gap ratio (C / DW): 0.0475

[0053] (Bearing F) Dynamic load rating (Cr): 945kN Basic static rated radial load (COr): 1330 kN Pocket clearance ratio (C / DW): 0.00573

[0054] (Test results) The inner rings of bearings D, E, and F were rotated at various rotational speeds, and the temperature of the outer ring for each rotational speed was measured. The test results are shown in Fig. 9. As described above, the pocket clearance ratio of bearing F is 0.00573. Therefore, hereinafter, with reference to Fig. 9, it will be mainly described whether there is a problem with the temperature of bearing F.

[0055] As shown in Fig. 9, at rotational speeds of 1300 min -1 , 1950 min -1 , and 2600 min -1 , the temperature rise of bearing F was lower than that of bearing E and showed the same temperature rise as bearing D. Also, the temperature rise of bearing F at 3250 min -1 was 115.1 °C, which was close to the temperature of 110.3 °C of bearing E at 2600 min -1 .

[0056] From the above results of the temperature rise of bearing F, after setting the outer ring seizure ratio rc / rout and the inner ring seizure ratio rc / rin to 94% or more and 98% or less, respectively, it can be said that the lower limit value of the pocket clearance ratio is 0.005, preferably 0.00573. As described above, from the results of Example 1 and Example 2, the appropriate range of the pocket clearance ratio C / DW is 0.005 < C / DW < 0.01.

[0057] In Example 1 and Example 2, the appropriate range of the pocket clearance ratio (0.005 < C / DW < 0.01) was verified. However, in order to further extend the service life of the self-aligning roller bearing 10, the outer ring seizure ratio rc / rout, the inner ring seizure ratio rc / rin, and the surface roughness of the outer ring raceway surface and the inner ring raceway surface were verified.

[0058] (Example 3) Bearings G and H used a bearing of model number 23960 (outer diameter: 420 mm, inner diameter: 300 mm, width: 90 mm) as the basic bearing, and the cage 40 (see Figs. 1, 3, and 6) was applied. The following will explain in detail.

[0059] The test conditions are as follows. Test radial load: 328500 N Test axial load: 0 N Inner ring rotation speed: 450 min -1 Lubrication method: JX Nippon Oil & Fats FBK Oil VG32, forced supply circulation Rolling surface roughness: 0.04 μm

[0060] The basic dynamic load rating (Cr), pocket clearance ratio (C / DW), outer ring interference ratio (rc / rout), inner ring interference ratio (rc / rin), outer ring raceway surface roughness, and inner ring raceway surface roughness of each bearing are as follows.

[0061] (Bearing G) Basic dynamic load rating (Cr): 731 kN Pocket clearance ratio (C / DW): 0.0232 Outer ring interference ratio (rc / rout): 0.973 Inner ring interference ratio (rc / rin): 0.966 Outer ring raceway surface roughness: 0.32 μm Inner ring raceway surface roughness: 0.18 μm

[0062] (Bearing H) Basic dynamic load rating (Cr): 783 kN Pocket clearance ratio (C / DW): 0.00583 Outer ring interference ratio (rc / rout): 0.961 Inner ring interference ratio (rc / rin): 0.945 Outer ring raceway surface roughness: 0.13 μm Inner ring raceway surface roughness: 0.06 μm

[0063] (Test results) The life ratio was calculated from the time until the outer ring edge was damaged when the inner rings of bearings G and H were rotated. For bearing G, the pocket clearance ratio, outer ring raceway surface roughness, and inner ring raceway surface roughness exceed the scope of the present invention (0.005 < C / DW < 0.01, the surface roughness of the outer ring raceway and inner ring raceway ≤ 0.13 μm).

[0064] On the other hand, the pocket gap ratio, outer ring contact ratio, inner ring contact ratio, outer ring raceway surface roughness, and inner ring raceway surface roughness of Bearing H are all within the range of the present invention. In the test results, assuming the life of Bearing G to be 1, the life ratio of Bearing H is 5.3, which is significantly longer than the life ratio of Example 1, and it was found that an extension of the life was achieved.

[0065] Example 4 Bearings J and K were based on model number 24128 bearings, and the cage 40 was used to verify the bearing temperature. This will be described in detail below. The test conditions are as follows. Test radial load: 113400N Test axial load: 0N Inner wheel rotation speed: 100 min -1 , 300min -1 , 600min -1 Lubrication method: Kyodo Yushi Unimax RNo2 grease lubrication

[0066] The basic dynamic load rating (Cr), pocket clearance ratio (C / DW), outer ring contact ratio (rc / rout), inner ring contact ratio (rc / rin), outer ring raceway surface roughness, and inner ring raceway surface roughness for each bearing are as follows.

[0067] (Bearing J) Basic dynamic load rating (Cr): 945kN Pocket gap ratio (C / DW): 0.00573 Outer ring ratio (rc / rout): 0.985 Inner circle ratio (rc / rin): 0.973 Outer ring raceway surface roughness: 0.15μm Inner ring raceway surface roughness: 0.07μm Roller surface roughness: 0.02μm

[0068] (Bearing K) Basic dynamic load rating (Cr): 945kN Pocket gap ratio (C / DW): 0.00573 Outer ring ratio (rc / rout): 0.969 Inner circle ratio (rc / rin): 0.959 Outer ring raceway surface roughness: 0.07μm Inner ring raceway surface roughness: 0.07μm Roller surface roughness: 0.02μm

[0069] (Test Results) The inner rings of bearings J and K were rotated at various rotation speeds, and the temperature of the outer ring was measured for each rotation speed. As shown in Figure 10, when the inner ring rotation speed was 100 min -1 , 300min -1 , 600min -1 The temperatures of the outer ring of bearing K at each rotation speed were 15.7°C, 35.2°C, and 57.5°C, which were lower than the temperatures of the outer ring of bearing J at each rotation speed, 18.9°C, 39.5°C, and 63.2°C, and were good results. As a result, it can be seen that compared to bearing J, in which the outer ring contact ratio and inner ring contact ratio exceed the ranges of the present invention and the outer ring raceway surface roughness also exceeds the ranges of the present invention, bearing K, in which the pocket clearance ratio, outer ring contact ratio, inner ring contact ratio, outer ring raceway surface roughness, inner ring raceway surface roughness, and roller surface roughness are all within the ranges of the present invention, is able to suppress temperature rise.

[0070] As described above, according to the self-aligning roller bearing 10 of this embodiment, the life of the self-aligning roller bearing 10 can be extended, and the effect of suppressing temperature rise can be obtained.

[0071] The present invention is not limited to the above-described embodiment, and can be modified, improved, etc. as appropriate.

[0072] As described above, the present specification discloses the following: (1) An outer ring having an outer ring raceway surface on its inner peripheral surface, an inner ring having an inner ring raceway surface on its outer peripheral surface, a plurality of rollers arranged between the outer ring raceway surface and the inner ring raceway surface and having rolling surfaces which roll on the inner ring raceway surface and the outer ring raceway surface, and a cage having pockets formed between a plurality of pillars extending in the axial direction and spaced apart in the circumferential direction, each of which can rotatably hold a plurality of rollers; A self-aligning roller bearing comprising: If a circle that is centered on the central axis of the outer ring and the inner ring and passes through the axis of the roller is defined as a pitch circle, When the distance between the inner surfaces of the column portions adjacent in the circumferential direction along the pitch circle minus the maximum diameter of the roller is defined as a pocket gap C, the pocket gap C divided by the maximum diameter DW of the roller is a pocket gap ratio C / DW that is greater than 0.005 and less than 0.01 (0.005 <C / DW<0.01)、 Furthermore, when the radius of curvature of the outer ring raceway surface in the axial direction is rout, the radius of curvature of the inner ring raceway surface in the axial direction is rin, and the radius of curvature of the rolling surface of the roller in the axial direction is rc, the outer ring contact ratio rc / rout and the inner ring contact ratio rc / rin are 94% or more and 98% or less, respectively. Spherical roller bearing. According to this configuration, the self-aligning roller bearing has a longer life and the effect of suppressing temperature rise is obtained.

[0073] (2) the surface roughness of the outer ring raceway surface and the inner ring raceway surface is 0.13 μm or less; The self-aligning roller bearing according to (1). With this configuration, the amount of heat generated during operation of the self-aligning roller bearing can be suppressed. [Explanation of symbols]

[0074] 10 Spherical roller bearings 20. Inner Circle 21 Inner ring raceway surface 30 Outer Ring 31 Outer ring raceway surface 40, 45, 47 retainer 42 Column section 42a Inside surface 43 Pocket Around 50 51 Rolling surface C Pocket gap C / DW pocket gap ratio C1 Center axis of outer and inner rings C2 Roller shaft center DW Maximum roller diameter PC Pitch Circle rc Radius of curvature of the rolling surface of the roller in the axial direction rc / rin Inner circle rate rc / rout Outer ring carrying rate rin Radius of curvature of the inner ring raceway in the axial direction rout Radius of curvature of the outer ring raceway in the axial direction

Claims

1. an outer ring having an outer ring raceway surface on its inner peripheral surface, an inner ring having an inner ring raceway surface on its outer peripheral surface, a plurality of rollers arranged between the outer ring raceway surface and the inner ring raceway surface and having rolling surfaces which roll on the inner ring raceway surface and the outer ring raceway surface, and a cage having pockets formed between a plurality of pillars extending in the axial direction and spaced apart in the circumferential direction, for rotatably holding each of the plurality of rollers; A self-aligning roller bearing comprising: If a circle that is centered on the central axis of the outer ring and the inner ring and passes through the axis of the roller is defined as a pitch circle, When a pocket gap C is defined as a distance along the pitch circle between inner surfaces of the column portions adjacent in the circumferential direction minus a maximum diameter of the roller, a pocket gap ratio C / DW obtained by dividing the pocket gap C by the maximum diameter DW of the roller is greater than 0.005 and less than 0.01 (0.005<C / DW<0.01), and when the radius of curvature of the outer ring raceway surface in the axial direction is rout, the radius of curvature of the inner ring raceway surface in the axial direction is rin, and the radius of curvature of the rolling surface of the roller in the axial direction is rc, the outer ring contact ratio rc / rout and the inner ring contact ratio rc / rin are 94% or more and 98% or less, respectively. Spherical roller bearing.

2. The surface roughness of the outer ring raceway surface and the inner ring raceway surface is 0.13 μm or less.

2. The spherical roller bearing according to claim 1.

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