JP2006112555A - Roller bearing with aligning ring - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve bearing life by preventing heat generation and wear even when creep occurs between an inner surface concave spherical surface of an aligning ring and an outer diameter convex spherical surface of an outer ring.
In the example of (a), a large number of pockets 21 serving as oil reservoirs are machined in the inner diameter of the aligning ring 12. Even when creep occurs between the inner surface concave spherical surface 13 of the aligning ring 12 and the outer diameter convex spherical surface 14 of the outer ring 2 by applying a lubricant such as grease to the pocket 21 during assembly. The lubricant and the like held on the surface can suppress heat generation and prevent wear, and can significantly improve the bearing life. In addition, the alignment between the inner diameter concave spherical surface 13 of the aligning ring 12 and the outer diameter convex spherical surface 14 of the outer ring 2 can be maintained well by the lubricant or the like held in the pocket 21. In the example of (b), a large number of pockets 21 serving as oil reservoirs are processed on the outer diameter of the outer ring 2.
[Selection] Figure 2

Description

  The present invention supports a rotating shaft such as a central axis of a roll for a rolling mill in which a thrust load is applied in addition to a large radial load, the length of the shaft is large, and deformation (bending) of the shaft due to the load is relatively large. In particular, even when the rotation axis tends to tilt, it prevents local loads such as edge loads from being applied to each component, improving the reliability and durability of the rotation support section The present invention relates to a roller bearing with a centering ring.

  Cylindrical roller bearings, tapered roller bearings, and self-aligning roller bearings with large load capacities are widely used as rolling bearings for incorporation into rotating support parts that support large radial loads such as the center axis of rolling mill rolls. Has been. A cylindrical roller bearing with a centering ring in which a centering ring is provided around an outer ring constituting the cylindrical roller bearing is also known. In the case of a cylindrical roller bearing with an aligning ring, if the center axis of the aligning ring and the center axis of the outer ring tend to be inconsistent, the outer ring and the aligning ring are relatively oscillated and displaced. This prevents local loads such as edge loads from being applied to some cylindrical roller bearings.

  In the case of the conventional rolling bearing as described above, when a thrust load is supported in addition to a large radial load and the rotation shaft tends to tilt, a local load such as an edge load is applied to each component part. It was difficult to prevent this, or it was inevitable that the cost was high.

  First, in the case of general cylindrical roller bearings and tapered roller bearings, the outer ring, the inner ring raceways, and the rolling surfaces of the rollers are all simply cylindrical surfaces or conical curved surfaces, so that the rotation axis is inclined. Edge load is applied to the contact portion between both ends of the rolling surface and both the outer ring and the inner ring raceway. Based on this edge load, excessive contact pressure acts on the contact portion between these rolling surfaces and the outer ring and inner ring raceways, which not only impairs the durability of the roller bearing, but also causes galling in severe cases. It may cause damage such as burn-in.

  In the case of a self-aligning roller bearing, edge load can be prevented and a thrust load of a certain size can be supported. In addition to the possibility of local wear, it is inevitable that the production of spherical rollers is cumbersome and costly. Further, in the case of a cylindrical roller bearing with an aligning ring provided with an aligning ring around the cylindrical roller bearing, there is almost no function of supporting a thrust load. For this reason, when it is used for a rotation support portion that needs to support a very large radial load such as a roll for a rolling mill, the load capacity may be insufficient.

  From such a background, Patent Document 1 uses a double-row tapered roller bearing with a centering mechanism. In other words, double-row tapered roller bearings with a centering mechanism support a large thrust load in addition to a large radial load, and even when the rotating shaft tends to tilt, local loads such as edge loads are applied to each component part. A structure capable of preventing the addition can be obtained at a low cost.

  The double-row tapered roller bearing with a centering mechanism includes one outer ring, a pair of inner rings, a plurality of tapered rollers, and a centering ring. Of these, the outer ring forms a double-row outer ring raceway on the inner peripheral surface. Each of these outer ring raceways has a conical concave shape and is inclined in directions opposite to each other, and in a direction in which the inner diameter increases toward each opening. Further, the pair of inner rings form conical convex inner ring raceways on their outer peripheral surfaces. The pair of inner rings formed in this way are arranged inside the outer ring with the end faces on the small diameter side of each inner ring raceway facing each other. A plurality of tapered rollers are provided between each outer ring raceway and each inner ring raceway. Further, the aligning ring is arranged around the outer ring. The inner peripheral surface of the aligning ring is a spherical concave surface centered on a point on the center axis of the aligning ring, and the outer peripheral surface of the outer ring is a spherical surface centered on a point on the center axis of the outer ring. Convex surface. A centering function is provided by fitting the inner peripheral surface of these aligning rings and the outer peripheral surface of the outer ring to the swinging displacement of these aligning wheels and the outer ring without looseness. .

  According to the double-row tapered roller bearing with the alignment mechanism configured as described above, it is possible to support a thrust load in addition to a large radial load. That is, since the plurality of tapered rollers are arranged in a double row, the radial load capacity of the plurality of tapered rollers can be increased. Even when a thrust load is applied between the outer ring and the inner ring, the tapered load in any row is sandwiched between the outer ring raceway and the inner ring raceway in the thrust direction to support the thrust load. In addition, when the rotating shaft that externally supports the pair of inner rings tends to be inclined with respect to the housing that internally supports the aligning ring, the outer ring may swing and displace inside the aligning ring. Thus, the inclination is compensated, and the center axis of the outer ring and the center axis of the inner ring are kept matched. As a result, local load such as edge load is formed on the outer ring raceway on the inner peripheral surface of the outer ring and the contact portion between the inner ring raceway on the outer peripheral surface of the inner ring and the rolling surface of each tapered roller, which constitutes the main body portion of the double row tapered roller bearing. Can be prevented from being added. Moreover, since the tapered roller constituting this structure is a simple tapered surface with a rolling surface, the production is not troublesome as the spherical roller constituting the self-aligning roller bearing. Therefore, production costs are not increased.

Patent Document 2 discloses a cylindrical roller bearing with a centering mechanism using a cylindrical roller.
Japanese Patent Laid-Open No. 10-220467 JP-A-11-82495

  However, in the case of a double-row tapered roller bearing with a centering mechanism, if creep occurs between the inner surface concave spherical surface of the aligning ring and the outer surface convex spherical surface of the outer ring depending on the usage conditions, heat generation and wear are large. As a result, the bearing may be damaged. Here, creep refers to a phenomenon of relative displacement between the fitting surfaces.

  Conventionally, as a countermeasure against this, a countermeasure by surface treatment, solid lubrication, or the like is generally performed, but it is expensive in cost and has some problems in its durability.

  The present invention has been made in view of the circumstances as described above, and during use, even when creep occurs between the inner surface concave spherical surface of the aligning ring and the outer diameter convex spherical surface of the outer ring during use, An object of the present invention is to provide a roller bearing with a centering ring that can significantly improve the life of the bearing by reliably preventing heat generation and wear.

In order to achieve the above object, a roller bearing with an aligning ring according to claim 1 of the present invention is provided with a plurality of rollers movably interposed between an outer ring and an inner ring so that the outer ring can swing. In roller bearings with aligning rings that are fitted to aligning rings,
An oil groove or pocket serving as an oil reservoir is provided in at least one of the inner diameter concave spherical surface of the aligning ring and the outer diameter convex spherical surface of the outer ring.

  According to the present invention, since at least one of the inner diameter concave spherical surface of the aligning ring and the outer diameter convex spherical surface of the outer ring is provided with an oil groove or pocket serving as an oil reservoir, Even when creep occurs between the inner surface concave spherical surface of the aligning ring and the outer diameter convex spherical surface of the outer ring by applying a lubricant such as grease during assembly, the lubricant retained in the oil groove or pocket, etc. Thus, heat generation can be suppressed, wear can be prevented, and the bearing life can be remarkably improved.

  In addition, the alignment property between the inner surface concave spherical surface of the aligning ring and the outer diameter convex spherical surface of the outer ring can be maintained well by the lubricant or the like held in the oil groove or pocket.

  Further, by processing the oil groove or pocket to both ends of each part, even if the lubricant retained in the oil groove or pocket flows out, the lubricating oil of the bearing is discharged from both ends of the oil groove. By entering, even when creeping between the inner surface concave spherical surface of the aligning ring and the outer diameter convex spherical surface of the outer ring, heat generation can be suppressed and wear can be prevented, and the bearing life can be significantly improved. .

  Hereinafter, a roller bearing with a centering ring according to an embodiment of the present invention will be described with reference to the drawings.

(Double-row tapered roller bearing with alignment mechanism to which the present invention is applied)
FIG. 1 is a cross-sectional view of a double row tapered roller bearing with a centering mechanism to which the present invention is applied.

  The double-row tapered roller bearing 1 with a centering mechanism includes a single outer ring 2, a pair of inner rings 3 and 3, a plurality of tapered rollers 4 and 4, and a single aligning ring 12. Of these, the outer ring 2 has double-row outer ring raceways 5 and 5 formed on the inner peripheral surface. Each of the outer ring raceways 5 and 5 has a conical concave shape, and is inclined in directions opposite to each other and in a direction in which the inner diameter becomes larger toward the opening. Therefore, the inner diameter of the outer ring 2 is the smallest at the center and gradually increases toward the openings at both ends.

  The pair of inner rings 3 and 3 form conical convex inner ring raceways 6 and 6 on their outer peripheral surfaces. Further, an outer flange-like large-diameter side flange portion 7 is also provided on the outer peripheral surface of one end portion (left and right end portions in FIG. 1) of each inner ring 3, 3 at the large-diameter side end portion of the inner ring raceway 6. On the outer peripheral surface of the other end portion (center end portion in FIG. 1), a small-diameter side flange portion 8 having an outward flange shape is also formed at a portion located at the small-diameter side end portion of the inner ring raceway 6. The pair of inner rings 3 and 3 formed in this way are arranged in such a manner that the end faces on the small diameter side of the inner ring raceways 6 and 6, that is, the small diameter side flanges 8 and 8 face each other. It is arranged inside. In the illustrated example, a spacer 9 is sandwiched between the end faces of the pair of inner rings 3 and 3.

  Further, a plurality of tapered rollers 4 and 4 can be freely rolled into respective pockets (not shown) of the cages 10 and 10 between the outer ring raceways 5 and 5 and the inner ring raceways 6 and 6, respectively. It is provided in the state held in

  Further, the aligning ring 12 is disposed around the outer ring 2. The inner peripheral surface 13 of the aligning ring 12 is a spherical concave surface having a point O on the center axis X of the aligning ring 12 as its center. The outer peripheral surface 14 of the outer ring 2 is also a spherical convex surface with the point O on the central axis X of the outer ring 2 as its center. In the illustrated example, each of these points O is provided at the center position in the axial direction of the aligning ring 12 and the outer ring 2.

  Accordingly, the inner diameter of the inner peripheral surface 13 (inner diameter concave spherical surface) and the outer diameter of the outer peripheral surface 14 (outer diameter convex spherical surface) are the largest at the axial center of the aligning ring 12 or outer ring 2. Note that the radii of curvature of the inner peripheral surface 13 (inner diameter concave spherical surface) and the outer peripheral surface 14 (outer diameter convex spherical surface) are equal to each other. The outer peripheral surface of the aligning ring 12 is a simple cylindrical surface.

  The aligning ring 12 and the outer ring 2 in which both inner and outer peripheral surfaces are formed as described above are the inner peripheral surface 13 (inner diameter concave spherical surface) of the aligning ring 12 and the outer peripheral surface 14 (outer diameter convex spherical surface of the outer ring 2). ), And the centering ring 12 and the outer ring 2 can be freely oscillated and displaced without looseness.

  According to the double row tapered roller bearing 1 with the alignment mechanism configured as described above, it is possible to support a thrust load in addition to a large radial load. That is, since the plurality of tapered rollers 4 and 4 are arranged in a double row, the load capacity in the radial direction by the plurality of tapered rollers 4 and 4 can be increased. Further, even when a thrust load is applied between the outer ring 2 and the inner rings 3, 3, the tapered roller 4 in any row has a thrust direction between any outer ring raceway 5 and any inner ring raceway 6. Thrust load is supported by being pinched by

  Further, when a rotation shaft (not shown) that supports the fitting of the pair of inner rings 3 and 3 tends to be inclined with respect to the housing (not shown) that supports the fitting of the aligning ring 12, this alignment is performed. The outer ring 2 is oscillated and displaced inside the ring 12. Then, based on this swing displacement, the inclination is compensated so that the central axis of the outer ring 2 and the central axes of the pair of inner rings 3 and 3 remain in alignment. As a result, the outer ring raceways 5 and 5 provided on the inner peripheral surface of the outer ring 2 and the inner ring raceways 6 and 6 provided on the outer peripheral surfaces of the inner rings 3 and 3 constituting the main body portion of the double row tapered roller bearing 1 with the aligning mechanism. And it can prevent that local load, such as an edge load, is added to the contact part with the rolling surface of each tapered roller 4,4.

  Moreover, since the tapered rollers 4 and 4 constituting the double row tapered roller bearing 1 with a centering mechanism are simple tapered surfaces, spherical rollers constituting a conventionally known spherical roller bearing are known. The production is not troublesome. Therefore, production costs are not increased.

(First embodiment)
FIG. 2A is a half sectional view of the aligning ring according to the first embodiment of the present invention, and FIG. 2B is a half sectional view of the outer ring.

  In the example of FIG. 2A, a large number of pockets 21 serving as oil reservoirs are processed on the inner diameter of the aligning ring 12.

  As a result, even when creep occurs between the inner surface concave spherical surface 13 of the aligning ring 12 and the outer diameter convex spherical surface 14 of the outer ring 2 by applying a lubricant such as grease to the pocket 21 when assembled. The lubricant and the like held in the pocket 21 can suppress heat generation and prevent wear, and can significantly improve the bearing life.

  In addition, the alignment between the inner diameter concave spherical surface 13 of the aligning ring 12 and the outer diameter convex spherical surface 14 of the outer ring 2 can be maintained well by the lubricant or the like held in the pocket 21.

  In the example of FIG. 2B, a large number of pockets 21 serving as oil reservoirs are processed on the outer diameter of the outer ring 2.

  As a result, even when creep occurs between the inner surface concave spherical surface 13 of the aligning ring 12 and the outer diameter convex spherical surface 14 of the outer ring 2 by applying a lubricant such as grease to the pocket 21 when assembled. The lubricant and the like held in the pocket 21 can suppress heat generation and prevent wear, and can significantly improve the bearing life.

  In addition, the alignment between the inner diameter concave spherical surface 13 of the aligning ring 12 and the outer diameter convex spherical surface 14 of the outer ring 2 can be maintained well by the lubricant or the like held in the pocket 21.

  The pocket shape is not limited to a quadrangle (shown in FIG. 2), and may be a circle, an ellipse, or a polygon.

(Second Embodiment)
FIG. 3 is a half sectional view of the aligning ring according to the second embodiment of the present invention.

  In the present embodiment, a large number of oil grooves 22 serving as oil reservoirs are processed in the inner diameter of the aligning ring 12. The oil groove 22 is formed in a rectangular shape extending in the axial direction.

  As a result, even when creep occurs between the inner surface concave spherical surface 13 of the aligning ring 12 and the outer diameter convex spherical surface 14 of the outer ring 2 by applying a lubricant such as grease to the oil groove 22 during installation. The lubricant retained in the oil groove 22 can suppress heat generation and prevent wear, and can significantly improve the bearing life.

  Further, the alignment property between the inner surface concave spherical surface 13 of the aligning ring 12 and the outer diameter convex spherical surface 14 of the outer ring 2 can be well maintained by the lubricant or the like held in the oil groove 22.

  An oil groove 22 may be formed in the outer diameter convex spherical surface 14 of the outer ring 2.

(Third embodiment)
FIG. 4 is a half sectional view of the aligning ring according to the third embodiment of the present invention.

  In the present embodiment, a large number of oil grooves 22 serving as oil reservoirs are processed in the inner diameter of the aligning ring 12. The oil groove 22 is formed extending in the circumferential direction.

  As a result, even when creep occurs between the inner surface concave spherical surface 13 of the aligning ring 12 and the outer diameter convex spherical surface 14 of the outer ring 2 by applying a lubricant such as grease to the oil groove 22 during installation. The lubricant retained in the oil groove 22 can suppress heat generation and prevent wear, and can significantly improve the bearing life.

  Further, the alignment property between the inner surface concave spherical surface 13 of the aligning ring 12 and the outer diameter convex spherical surface 14 of the outer ring 2 can be well maintained by the lubricant or the like held in the oil groove 22.

  An oil groove 22 may be formed in the outer diameter convex spherical surface 14 of the outer ring 2.

(Fourth embodiment)
FIG. 5A is a half sectional view of the aligning ring according to the fourth embodiment of the present invention, and FIG. 5B is a half sectional view of the aligning ring according to the modification.

  In the present embodiment shown in FIG. 5A, a large number of oil grooves 22 serving as oil reservoirs are processed on the inner diameter of the aligning ring 12. The oil groove 22 is formed in a well shape extending in the axial direction and the circumferential direction.

  As a result, even when creep occurs between the inner surface concave spherical surface 13 of the aligning ring 12 and the outer diameter convex spherical surface 14 of the outer ring 2 by applying a lubricant such as grease to the oil groove 22 during installation. The lubricant retained in the oil groove 22 can suppress heat generation and prevent wear, and can significantly improve the bearing life.

  Further, the alignment property between the inner surface concave spherical surface 13 of the aligning ring 12 and the outer diameter convex spherical surface 14 of the outer ring 2 can be well maintained by the lubricant or the like held in the oil groove 22.

  An oil groove 22 may be formed in the outer diameter convex spherical surface 14 of the outer ring 2.

  In the modification shown in FIG. 5B, a large number of oil grooves 22 serving as oil reservoirs are processed on the inner diameter of the aligning ring 12. The oil groove 22 is formed in a well shape that extends obliquely.

  As a result, even when creep occurs between the inner surface concave spherical surface 13 of the aligning ring 12 and the outer diameter convex spherical surface 14 of the outer ring 2 by applying a lubricant such as grease to the oil groove 22 during installation. The lubricant retained in the oil groove 22 can suppress heat generation and prevent wear, and can significantly improve the bearing life.

  Further, the alignment property between the inner surface concave spherical surface 13 of the aligning ring 12 and the outer diameter convex spherical surface 14 of the outer ring 2 can be well maintained by the lubricant or the like held in the oil groove 22.

  An oil groove 22 may be formed in the outer diameter convex spherical surface 14 of the outer ring 2.

(Fifth embodiment)
FIG. 6A is a half sectional view of the aligning ring according to the fifth embodiment of the present invention, and FIG. 6B is a half sectional view of the aligning ring according to the modification.

  In the present embodiment shown in FIG. 5A, a large number of oil grooves 22 serving as oil reservoirs are processed on the inner diameter of the aligning ring 12. The oil groove 22 is formed in a spiral shape.

  As a result, even when creep occurs between the inner surface concave spherical surface 13 of the aligning ring 12 and the outer diameter convex spherical surface 14 of the outer ring 2 by applying a lubricant such as grease to the oil groove 22 during installation. The lubricant retained in the oil groove 22 can suppress heat generation and prevent wear, and can significantly improve the bearing life.

  Further, the alignment property between the inner surface concave spherical surface 13 of the aligning ring 12 and the outer diameter convex spherical surface 14 of the outer ring 2 can be well maintained by the lubricant or the like held in the oil groove 22.

  An oil groove 22 may be formed in the outer diameter convex spherical surface 14 of the outer ring 2.

  In the modification shown in FIG. 5B, a large number of oil grooves 22 serving as oil reservoirs are processed on the inner diameter of the aligning ring 12.

  The oil groove 22 is formed in a spiral shape, and in addition, the lubricant held in the oil groove 22 flows out by processing the oil groove 22 to both ends of each component (aligning ring 12). Even if it is a case, even if it creeps between the internal-diameter recessed spherical surface 13 of the aligning ring 12 and the external-diameter convex spherical surface 14 of the outer ring 2 by the lubricating oil of the bearing entering from both ends of the oil groove 22 In addition, heat generation can be suppressed, wear can be prevented, and bearing life can be significantly improved.

  Even when creep occurs between the inner surface concave spherical surface 13 of the aligning ring 12 and the outer diameter convex spherical surface 14 of the outer ring 2 by applying a lubricant such as grease to the oil groove 22 during installation. The lubricant retained in the groove 22 can suppress heat generation and prevent wear, and can significantly improve the bearing life. Furthermore, the aligning property between the inner surface concave spherical surface 13 of the aligning ring 12 and the outer diameter convex spherical surface 14 of the outer ring 2 can be well maintained by the lubricant or the like held in the oil groove 22. An oil groove 22 may be formed in the outer diameter convex spherical surface 14 of the outer ring 2.

  Further, also in the second embodiment (FIG. 3) and the fourth embodiment (FIGS. 5A and 5B) described above, the oil groove 22 is provided at both ends of each component (for example, the aligning ring 12). May be processed.

(Shape of oil groove or pocket)
7A, 7B, and 7C are schematic views showing the cross-sectional shapes of the oil grooves or pockets, respectively.

  The cross-sectional shape of the oil groove 22 or the pocket 21 may be a quadrangular shape as shown in FIG. 7A, an arc shape (R shape) as shown in FIG. Thus, it may be triangular, and may be other circles or polygons, and the cross-sectional shape is not limited.

(Cylinder roller bearing with aligning mechanism to which the present invention is applied)
FIG. 8 is a sectional view of a cylindrical roller bearing with a centering mechanism to which the present invention is applied.

  The application target of the present invention is not limited to the double-row tapered roller bearing with the aligning mechanism, and can be applied to other roller bearings with the aligning ring such as the cylindrical roller bearing with the aligning mechanism.

  For example, in a rolling machine of a continuous casting facility, in order to absorb bending of a roll that occurs during rolling of a steel plate or the like, the free side of the roll is supported by a cylindrical roller bearing with an aligning ring having alignment properties.

  FIG. 8 illustrates a full-roller type cylindrical roller bearing with a centering ring. This bearing supports, for example, the free side of a roll of a rolling mill, and an outer ring 32 having an inner ring 31 fitted to a roll (not shown) and a spherical outer diameter surface 32a (outer diameter convex spherical surface). And a plurality of cylindrical rollers 33 interposed between the inner ring 31 and the outer ring 32, and a spherical inner diameter that is fitted into the bearing housing and into which the outer diameter surface 32a (outer diameter convex spherical surface) of the outer ring 32 is fitted. And a centering ring 34 having a surface 34a (inner diameter concave spherical surface).

  Both ends of the outer ring 32 are provided with flanges 32b, and the cylindrical rollers 33 are contacted and guided by both flanges 32b of the outer ring 32 when the bearing rotates. Further, when the roll is bent, the outer ring 32 is aligned and tilted with respect to the aligning ring 34, and the roll is absorbed.

  In addition, this invention is not limited to embodiment mentioned above, A various deformation | transformation is possible.

It is sectional drawing of the double row tapered roller bearing with a centering mechanism used as the application object of this invention. (A) is related to 1st Embodiment of this invention, and is a half sectional view of a centering ring, (b) is a half sectional view of an outer ring. FIG. 7 is a half sectional view of a centering ring according to a second embodiment of the present invention. FIG. 6 is a half sectional view of a centering ring according to a third embodiment of the present invention. (A) is a half cross-sectional view of the aligning ring according to the fourth embodiment of the present invention, and (b) is a half cross-sectional view of the aligning ring according to the modification. (A) is a half cross-sectional view of the aligning ring according to the fifth embodiment of the present invention, and (b) is a half cross-sectional view of the aligning ring according to the modification. (A) (b) (c) is a schematic diagram which shows the cross-sectional shape of an oil groove or a pocket, respectively. It is sectional drawing of the cylindrical roller bearing with a centering mechanism used as the application object of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Double row tapered roller bearing with alignment mechanism 2 Outer ring 3 Inner ring 4 Tapered roller 5 Outer ring raceway 6 Inner ring raceway 7 Large diameter side flange 8 Small diameter side flange 9 Spacer 10 Cage 12 Alignment ring 13 Inner circumferential surface (inner diameter Concave spherical surface)
14 Outer peripheral surface (spherical spherical surface with outer diameter)
21 Pocket 22 Oil groove 31 Inner ring 31
32 Outer ring 32a Outer diameter surface (outer diameter convex spherical surface)
32b flange 33 cylindrical roller 34 aligning ring 34a inner diameter surface (inner diameter concave spherical surface)

Claims (1)

In a roller bearing with an aligning ring in which a plurality of rollers are interposed between the outer ring and the inner ring so as to be able to roll, and the outer ring is slidably fitted to the aligning ring.
A roller bearing with an aligning ring, wherein an oil groove or pocket serving as an oil reservoir is provided in at least one of an inner diameter concave spherical surface of the aligning ring and an outer diameter convex spherical surface of the outer ring.

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