JP5929481B2 - Spherical roller bearings and rotating equipment - Google Patents

Description

  The present invention relates to a self-aligning roller bearing in which an outer ring rotates, and a rotating device including the self-aligning roller bearing.

  An example of a self-aligning roller bearing is described in Patent Document 1. As shown in FIG. 5, the self-aligning roller bearing has an outer ring 93 in which an outer ring raceway 96 having a concave curved surface is formed on the inner periphery, and inner ring races 94 and 95 having concave curved surfaces in the outer periphery. 92 and barrel-shaped rollers 90 and 91 are provided.

  The outer ring raceway 96 has a shape along a concave spherical surface, and since the center of the outer ring raceway 96 coincides with the center point P of the bearing, the bearing has self-alignment and the deflection of the shaft 98 Or the shaft 98 can be rotatably supported with respect to the housing 97 even when an inclination occurs between the inner ring 92 and the outer ring 93 due to a mounting error of the bearing with respect to the housing 97.

JP 2009-180307 A (see FIG. 1)

  As is generally known, the self-aligning roller bearing as shown in FIG. 5 has a self-aligning function when the inner ring 92 rotates, whereas it aligns when the outer ring 93 rotates. Cannot have function. This is due to the following reason. In FIG. 5, the straight line C <b> 1 is the center line of the outer ring 93, and the straight line C <b> 2 is the center line of the inner ring 92.

Since the rollers 90 and 91 are restricted from moving in the axial direction by the inner ring 92, when an inclination (tilt angle θ) occurs between the inner ring 92 and the outer ring 93, the rollers 90 and 91 follow the inner ring 92. It is the composition to do. That is, the rollers 90 and 91 roll around the center line C <b> 2 of the inner ring 92.
For this reason, when the inner ring 92 rotates around the center line C2, the rotation direction of the inner ring 92 and the rolling direction of the rollers 90 and 91 both coincide with each other around the center line C2. It can have a centering function.
On the other hand, when the outer ring 93 rotates around the center line C1, the rotation direction G1 of the outer ring 93 and the rolling direction G2 of the rollers 90 and 91 around the center line C2 of the inner ring 92 coincide. The rollers 90 and 91 generate a force in the axial direction (force toward the right side in the case of FIG. 5). This axial force is a force that causes the rollers 90 and 91 to deviate from the normal positions of the inner ring raceways 94 and 95.

  In this case, the sliding between the rollers 90 and 91 and the inner ring raceways 94 and 95 becomes large, and there is a possibility that troubles such as hindering smooth rotation and abnormal wear of the inner ring raceways 94 and 95 and the rollers 90 and 91 may occur. There is. Therefore, in the case of outer ring rotation, it is not possible to have a centering function as used in inner ring rotation.

  Accordingly, an object of the present invention is to provide a self-aligning roller bearing capable of having a self-aligning function even in the case of rotating the outer ring, and a rotating device having the self-aligning roller bearing. .

(1) The present invention provides an outer ring in which an outer ring raceway having a concave curved surface is formed on an inner periphery, an inner ring in which inner ring raceways having a concave curved surface are formed in two rows in the axial direction on the outer periphery, and the outer ring raceway And a pair of barrel-shaped rollers interposed between the inner ring raceway and the inner ring raceway, and the outer ring is a self-aligning roller bearing that rotates with respect to the inner ring. In order to restrict the movement to the outside in the axial direction, both outer sides in the axial direction have flanges protruding outward in the radial direction , and in each of the inner ring raceways, the radius of curvature of the inner region in the axial direction is , than the radius of curvature of the outer region of the radius of curvature and the axial direction of the outer ring raceway, rather large radius of curvature of the outer region, characterized in that said than the radius of curvature of the radius of curvature and the inner region of the outer ring raceway, small And

According to the present invention, when an inclination occurs between the rotating outer ring and the inner ring, a force inward in the axial direction is generated in one row of rollers (referred to as “first roller”), and the other row In the nose (referred to as “second roller”), a force directed outward in the axial direction is generated.
At this time, in the inner ring raceway on which the first roller rolls, the inner region has a radius of curvature larger than that of the outer region, so that a force toward the outer side in the axial direction (force due to the positive skew) is generated in the first roller. For this reason, the axially inward force generated in the first roller due to the inclination of the inner and outer rings is canceled out. Further, in the inner ring raceway on which the second roller rolls, the outer region has a smaller radius of curvature than the inner region, and therefore a force (force due to negative skew) directed inward in the axial direction is generated in the second roller. For this reason, the axially outward force generated in the second roller due to the inclination of the inner and outer rings is canceled out.
As described above, the axial force acting on the first roller and the second roller due to the inclination of the inner and outer rings can be canceled, thereby preventing the occurrence of problems such as abnormal wear as in the prior art. In the case of rotating the outer ring, it is possible to have a centering function.

Also, the radius of curvature of the outer region of the inner ring raceway is from said smaller than the radius of curvature of the outer ring raceway, the force due to the positive skew, it is possible to generate a force due to the negative skew effectively.

( 2 ) Further, in each of the inner ring raceways, it is preferable that the radius of curvature decreases continuously or stepwise from the inner region toward the outer region.
In this case, a configuration is obtained in which the radius of curvature gradually decreases from the inner region toward the outer region, and even if the inner and outer rings are inclined, a good contact state between the rollers and the inner ring raceway is obtained.

( 3 ) Further, the rotating device of the present invention includes a shaft, a housing that is provided on the outer side in the radial direction of the shaft, and that rotates around the shaft, and that is provided between the shaft and the housing and is rotatable The spherical roller bearing has an outer ring raceway having a concave curved surface formed on the inner periphery, and an outer ring that rotates integrally with the housing, and is fixed to the shaft and recessed on the outer periphery. comprising an inner ring inner raceway consisting of curved surfaces are formed two rows side by side in the axial direction, and said rollers of barrel-shaped two rows is interposed between the outer raceway and the inner raceway respectively, said inner race , for the rollers to regulate the movement in the axial outward direction on both outer sides in the axial direction, it has a flange portion which projects radially outward, in the inner ring raceway respectively axially inner territory Radius of curvature than the radius of curvature of the outer region of the radius of curvature and the axial direction of the outer ring raceway, rather large radius of curvature of the outer region, than the radius of curvature of the radius of curvature and the inner region of the outer ring raceway, It is small .

  According to the present invention, in a rotating device in which a housing rotates, even when there is an inclination between the inner ring and the outer ring due to deflection of the shaft or due to a mounting error of the shaft with respect to the housing, the self-aligning roller bearing Can have the same function and effect as the above (1) and have a centering function, and can support the housing rotatably.

  According to the present invention, the self-aligning roller bearing can have a centering function even when the outer ring rotates.

It is a longitudinal cross-sectional view which shows one Embodiment of the self-aligning roller bearing of this invention. It is a longitudinal cross-sectional view of an inner ring. (A) is explanatory drawing of the force, moment, etc. which act between a 1st roller and an outer ring, (B) is explanatory drawing of force, moment, etc. which act between this 1st roller and an inner ring. It is. (A) is explanatory drawing of the positive skew which acts on a roller, (B) is explanatory drawing of the negative skew which acts on a roller. It is explanatory drawing explaining the subject of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a longitudinal sectional view showing an embodiment of a self-aligning roller bearing of the present invention. A self-aligning roller bearing 10 of the present embodiment (hereinafter also simply referred to as a bearing 10) includes an outer ring 1, an inner ring 2, and a plurality of barrel-shaped rollers (spherical rollers) 3 and 4. The rollers 3 and 4 are provided in two rows between the outer ring 1 and the inner ring 2, and a plurality of rollers 3 and 4 are provided in the circumferential direction for each row. Furthermore, the bearing 10 includes a cage 5, and the cage 5 holds the rollers 3 (4) in each row at equal intervals in the circumferential direction.

  The self-aligning roller bearing 10 of FIG. 1 is provided in a rotating device including a shaft 7 and a housing 8 provided on the outer side in the radial direction of the shaft 7. That is, the bearing 10 is provided between the shaft 7 and the housing 8. In this rotating device, the housing 8 rotates around the shaft 7, and the bearing 10 supports the housing 8 so as to be rotatable with respect to the shaft 7.

  In the present embodiment, the right and left sides in FIG. 1, that is, both axial sides of the bearing 10 are defined as “axially outside”, and the axially central side of the bearing 10, that is, the space side between the rollers 3 and 4. It is defined as “inner axial direction”. Further, the center point of the outer ring 1 and the center point of the inner ring 2 coincide with each other, and this center point becomes the center point P of the self-aligning roller bearing 10.

  The outer ring 1 is fitted and fixed to the inner peripheral surface of the housing 8. As described above, in this embodiment, since the housing 8 rotates, the outer ring 1 rotates integrally with the housing 8. That is, in this bearing 10, the outer ring 1 rotates with respect to the inner ring 2.

  The outer ring 1 is configured symmetrically across a virtual plane passing through the center point P and orthogonal to the center line of the outer ring 1, and a single outer ring raceway 11 is formed on the inner periphery of the outer ring 1. The outer ring raceway 11 has a shape along a spherical surface having a predetermined radius from a point (center point P) on the center line of the outer ring 1. Therefore, the outer ring raceway 11 is formed of a concave curved surface (a part of a spherical surface), and the center of the outer ring raceway 11 coincides with the center point P of the bearing 10. As shown in FIG. 1, the shape of the outer ring raceway 11 is an arc in a cross section (vertical cross section) including the center line of the outer ring 1.

The inner ring 2 is fitted on the outer peripheral surface of the shaft 7 and is fixed to the shaft 7.
The inner ring 2 is configured symmetrically with a virtual plane passing through the center point P and perpendicular to the center line of the inner ring 2, and two rows of inner ring raceways 21 and 22 are arranged in the axial direction on the outer periphery of the inner ring 2. Is formed. Each of the inner ring raceways 21 and 22 is formed of a concave curved surface. As shown in FIG. 1, the shape of each of the inner ring raceways 21 and 22 is an arc in a cross section (longitudinal cross section) including the center line of the inner ring 2. However, as will be described in detail later, this arc is not an arc having a constant curvature radius but an arc having a plurality of (gradually changing) curvature radii.

A cylindrical surface 23 is formed on the outer peripheral surface of the inner ring 2 between the two rows of inner ring races 21 and 22, and the cylindrical surface 23 is a surface parallel to the center line of the inner ring 2.
Further, the inner ring 2 has flange portions 25 and 26 protruding outward in the radial direction on both outer sides in the axial direction. The flange portions 25 and 26 move the rollers 3 and 4 outward in the axial direction. Is regulated.

  The inner ring 2 having such a configuration has a large-diameter portion 27 having a cylindrical surface 23 as an outer peripheral surface, a small-diameter portion 28 including the flange portion 25, and a small-diameter portion 29 including the flange portion 26. One inner ring raceway 21 is formed on the outer peripheral surface of the inner ring 2 between the large diameter part 27 and one small diameter part 28, and the inner ring between the large diameter part 27 and the other small diameter part 29 is formed. The other inner ring raceway 22 is formed on the outer peripheral surface 2.

The rollers 3 and 4 are barrel-shaped and have an outer peripheral surface made of a convex curved surface. The rollers 3 and 4 are interposed between the outer ring raceway 11 and the inner ring raceways 21 and 22, and the outer ring raceway 11 and the inner ring raceways 21 and 22. Roll over. The rollers 3 included in the left column in FIG. 1 are referred to as “first rollers 3”. The rollers 4 included in the right column in FIG. 1 are referred to as “second rollers 4”. The first roller 3 and the second roller 4 have the same shape.
The shape of the outer peripheral surface of the roller 3 (4) is an arc in the cross section including the center line of the roller 3 (4). In the present embodiment, the radius of curvature Rr of the arc in the cross section of the roller 3 (4) is set slightly smaller than the radius of curvature Ra of the outer ring raceway 11 (Rr <Ra).

FIG. 2 is a longitudinal sectional view of the inner ring 2. As described above, each of the inner ring raceways 21 and 22 is formed of a concave curved surface, and the cross-sectional shape thereof is an arc formed of a plurality of curvature radii.
The inner ring raceway 21 on which the first roller 3 rolls has an outer region 31 on the outer side in the axial direction and an inner region 32 on the inner side in the axial direction. The inner ring raceway 21 is divided into two in the axial direction, with the left side being an outer region 31 and the right side being an inner region 32. The curvature radius r2 of the inner region 32 is configured to be larger than the curvature radius r1 of the outer region 31 (r2> r1).
In the present embodiment, the curvature radius r1 of the outer region 31 is set to be smaller than the curvature radius Ra of the outer ring raceway 11 (r1 <Ra), and the curvature radius r2 of the inner region 32 is the curvature radius Ra of the outer ring raceway 11. (R2> Ra).

The inner ring raceway 22 on which the second roller 4 rolls has an outer region 33 on the outer side in the axial direction and an inner region 34 on the inner side in the axial direction. The inner ring raceway 22 is divided into two in the axial direction, with the left side being an inner region 34 and the right side being an outer region 33. The curvature radius r4 of the inner region 34 is set larger than the curvature radius r3 of the outer region 33 (r4> r3).
In the present embodiment, the curvature radius r3 of the outer region 33 is set smaller than the curvature radius Ra of the outer ring raceway 11 (r3 <Ra), and the curvature radius r4 of the inner region 34 is the curvature radius Ra of the outer ring raceway 11. (R4> Ra).

  Regarding the left inner ring raceway 21, the radius of curvature r2 of the inner region 32 is not constant, and the radius of curvature r2 may change gradually (continuously or stepwise) within the inner region 32. Further, the radius of curvature r1 of the outer region 31 is not constant, and the radius of curvature r1 may change gradually (continuously or stepwise) within the outer region 31. However, even in this case, in the inner region 32 and the outer region 31, the inner ring raceway 21 is formed so that the radius of curvature decreases from the large diameter portion 27 side toward the small diameter portion 28 side. That is, the radius of curvature decreases continuously or stepwise from the inner region 32 toward the outer region 31.

  Similarly, with respect to the right inner ring raceway 22, the radius of curvature r4 of the inner region 34 is not constant, and the radius of curvature r4 gradually changes (continuously or stepwise) within the inner region 34. It may be. Further, the radius of curvature r3 of the outer region 33 is not constant, and the radius of curvature r3 may change gradually (continuously or stepwise) within the outer region 33. However, even in this case, the inner ring raceway 22 is formed in the inner region 34 and the outer region 33 so that the radius of curvature decreases from the large diameter portion 27 side toward the small diameter portion 29 side. That is, the radius of curvature decreases from the inner region 34 toward the outer region 33 continuously or stepwise.

The alignment function of the bearing 10 according to the present embodiment having the above configuration will be described.
In the following description, as shown by a two-dot chain line in FIG. 1, the rotating outer ring 1 is displaced counterclockwise around the center point P and tilted with respect to the center line of the inner ring 2.

In this way, when the rotating outer ring 1 is inclined, the first roller 3 rolling on the left inner ring raceway 21 generates a force F1 directed inward in the axial direction (right side in FIG. 1), and the right inner ring raceway is generated. The second roller 4 that rolls 22 generates a force F <b> 2 directed outward in the axial direction (right side in FIG. 1).
In the left inner ring raceway 21, as described above (see FIG. 2), the inner region 32 has a larger radius of curvature than the outer region 31 (r2> r1). Produces a force f1 directed outward in the axial direction (left side in FIG. 1). This force f1 is a force when the first roller 3 is skewed, and is referred to as a “force f1 due to a positive skew”.
The principle of generating the force f1 due to the positive skew is as follows.

  First, the mechanism by which the first roller 3 is skewed will be described. FIG. 3A is an explanatory diagram of forces and moments acting between the first roller 3 and the outer ring 1, and FIG. 3B shows the action between the first roller 3 and the inner ring 2. It is explanatory drawing, such as a force and a moment to do. The bearing shown in FIG. 3 is a virtual bearing unlike the bearing 10 of the present embodiment, and has a radius of curvature (constant) of the inner ring raceway 21 and a radius of curvature (constant) of the inner ring raceway 22; The radius of curvature (constant) of the outer ring raceway 11 is the same, and the radius of curvature of this raceway is set slightly larger than the radius of curvature of the outer peripheral surfaces of the rollers 3 and 4. The radius of curvature of the outer ring raceway 11 and the radius of curvature of the outer peripheral surfaces of the rollers 3 and 4 are the same as those of the bearing 10 of the present embodiment.

Between the first roller 3 and the outer ring raceway 11, surface pressure, slip (slip speed), and frictional force act in a distribution shown in FIG. The sliding speed is a difference in the circumferential speed between the first roller 3 and the outer ring raceway 11, and the circumferential speed is the same at the “pure rolling point”. In this case, a moment M1 (skew moment M1) acts on the first roller 3 in contact with the outer ring raceway 11.
On the other hand, between the first roller 3 and the inner ring raceway 21, surface pressure, slip (slip speed), and frictional force act in a distribution shown in FIG. In this case, a moment M2 (skew moment M2) acts on the first roller 3 in contact with the inner ring raceway 21.

  In the case of this virtual bearing, the moment M1 and the moment M2 have the same magnitude and opposite directions, so both moments are balanced (M1 = M2), and the skew moment acting on the first roller 3 Becomes zero. That is, the first roller 3 is considered not to skew.

However, when the contact state between the first roller 3 and the inner ring raceway 21 changes, that is, when the radius of curvature of the inner ring raceway 21 is set as described above as in this embodiment, the balance of moment (M1 = M2) is lost. .
For example, when the moment M1 due to the contact with the outer ring 1 becomes larger than the moment M2 due to the contact with the inner ring 2 (M1> M2), as shown in FIG. A force to go to the left) is generated and skews. This is the positive skew.
On the contrary, when the moment M1 due to contact with the outer ring 1 is smaller than the moment M2 due to contact with the inner ring 2 (M1 <M2), as shown in FIG. 4 (B), as shown in FIG. Contrary to the case, a force is generated in the first roller 3 toward the inner side (right side) in the axial direction, and the first roller 3 is skewed. This is a negative skew.

Therefore, in the case of the bearing 10 of the present embodiment, as described above, since the outer ring 1 is inclined, the first roller 3 has a force F1 directed inward in the axial direction (see FIG. 1). The first roller 3 tries to contact the inner region 32 side of the inner ring raceway 21 (see FIG. 2). The curvature radius r2 of the inner region 32 is the curvature radius Ra of the outer ring raceway 11 and the curvature radius of the outer region 31. Since it is set to be larger than r1, the contact range (contact width) in the inner region 32 is smaller than that of the outer ring raceway 11 (that is, it becomes point contact), and the moment M2 due to contact with the inner ring 2 is reduced. . Even in this case, the moment M1 due to contact with the outer ring 1 does not change. Therefore, the relationship of moment is M1> M2, and a force f1 (see FIG. 1) due to the positive skew is generated in the first roller 3.
Therefore, the force F1 of the first roller 3 toward the inner side in the axial direction due to the inclination of the inner and outer rings is canceled out by the force f1 due to the positive skew.

Then, the second roller 4 will be described. Since the outer ring 1 is inclined, the second roller 4 has a force F2 directed outward in the axial direction (see FIG. 1). The inner ring raceway 22 (see FIG. 2) tries to come into contact with the outer region 33 side, but the radius of curvature r3 of the outer region 33 is set smaller than the curvature radius Ra of the outer ring raceway 11 and the curvature radius r4 of the inner region 34. Therefore, the contact range (contact width) in the outer region 33 is larger than that of the outer ring raceway 11, and the moment M2 due to contact with the inner ring 2 is increased. Even in this case, the moment M1 due to contact with the outer ring 1 does not change. Therefore, the relationship of moment is M1 <M2, and a force f2 (see FIG. 1) due to the negative skew is generated in the second roller 4.
Therefore, the force F2 that the second roller 4 moves outward in the axial direction due to the inclination of the inner and outer rings is canceled by the force f2 caused by this negative skew.

  From the above, due to the inclination of the inner and outer rings, the axial forces F1 and F2 acting on the rollers 3 and 4, that is, the forces that the rollers 3 and 4 try to deviate from the normal positions of the inner ring raceways 21 and 22. (F1, F2) can be reduced by the force f1 due to the positive skew and the force f2 due to the negative skew, so that smooth rotation is maintained, abnormal wear between the rollers 3, 4 and the inner ring 2, etc. Can be prevented from occurring. As a result, it is possible to have an effective alignment function even in the case of outer ring rotation.

  Accordingly, in the rotating device in which the housing 8 rotates as shown in FIG. 1, the housing 8 can be rotated with respect to the shaft 7 even if the shaft 7 is bent to cause an inclination between the rotating outer ring 1 and the inner ring 2. Can be supported. Further, even if an attachment error of the bearing 10 with respect to the housing 8 occurs and an inclination occurs between the rotating outer ring 1 and the inner ring 2, the housing 8 can be rotatably supported on the shaft 7. That is, it is possible to set a large allowable value for the mounting error, and it is possible to improve the robustness of the bearing.

In each of the inner ring raceways 21 and 22, the radius of curvature gradually decreases from the inner area 32 and 34 toward the outer area 31 and 33, so that even if the inner and outer rings are inclined, the rollers 3 and 4 and the inner ring Good contact with the tracks 21 and 22 is obtained.
Further, the self-aligning roller bearing of the present invention is not limited to the illustrated form, but may be of another form within the scope of the present invention.

  1: Outer ring 2: Inner ring 3: First roller 4: Second roller 7: Shaft 8: Housing 10: Bearing (Spherical roller bearing) 11: Outer ring raceway 21: Inner ring raceway 22: Inner ring raceway 31: Outer region 32: Inner region 33: Outer region 34: Inner region r1, r2, r3, r4: radius of curvature of inner ring raceway Ra: radius of curvature of outer ring raceway

Claims (3)

An outer ring in which an outer ring raceway made of a concave curved surface is formed on the inner periphery, an inner ring in which inner ring raceways made of a concave curved surface are formed in two rows along the axial direction on the outer periphery, and each of the outer ring track and the inner ring track Two rows of barrel-shaped rollers interposed therebetween, wherein the outer ring is a self-aligning roller bearing that rotates relative to the inner ring,
The inner ring has flanges protruding outward in the radial direction on both outer sides in the axial direction in order to restrict the rollers from moving outward in the axial direction.
In the inner ring raceway, respectively, the radius of curvature of the axially inner region than said radius of curvature of the radius of curvature and the axial direction of the outer region of the outer ring raceway, rather large radius of curvature of the outer region, the curvature of the outer ring raceway A self-aligning roller bearing having a radius smaller than a radius of curvature of the inner region . 2. The self-aligning roller bearing according to claim 1 , wherein the radius of curvature of each of the inner ring raceways decreases continuously or stepwise from the inner region toward the outer region. A shaft, a housing provided on the outer side in the radial direction of the shaft, and rotating about the shaft; and a self-aligning roller bearing provided between the shaft and the housing to rotatably support the housing. And
The spherical roller bearing is
An outer ring formed with a concave curved surface on the inner periphery and rotating integrally with the housing; an inner ring formed with two rows of inner ring tracks fixed to the shaft and formed with a concave curved surface along the axial direction; Two rows of barrel rollers interposed between the outer ring raceway and each of the inner ring raceways,
The inner ring has flanges protruding outward in the radial direction on both outer sides in the axial direction in order to restrict the rollers from moving outward in the axial direction.
In the inner ring raceway, respectively, the radius of curvature of the axially inner region than said radius of curvature of the radius of curvature and the axial direction of the outer region of the outer ring raceway, rather large radius of curvature of the outer region, the curvature of the outer ring raceway A rotating device characterized by being smaller than a radius and a radius of curvature of the inner region .

Images