JP2010139035A - Self-aligning roller bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a self-aligning roller bearing with a long life which does not cause premature peeling to be generated by a superficial damage such as peeling. <P>SOLUTION: The self-aligning roller bearing 1 is provided with an inner ring 2, an outer ring 3 and double-row of spherical rollers 4 rollably arranged between the inner and outer rings 2, 3. The roller bearing is formed with raceway surfaces 2a, 2a of the double-row of spherical rollers 4 on outer peripheral surface of the inner ring 2 wherein inner peripheral surface of the outer ring 3 is formed as double-row one piece spherical raceway surface 3a. The spherical raceway surface 3a of the outer ring 3 is configured so that a solid lubricant coating 11 is coated by shot blast of a solid lubricant powder on metallic surface on which a fine groove 10 is formed and of which surface roughness Ra in axial and circumferential direction is regulated to be 0.1 μm or more and 1 μm or less wherein thickness of the solid lubricant coating 11 is regulated to be 1/10 or more and 1/2 or less of surface roughness Ra of the metallic surface. Then, surface roughness in the axial and circumferential direction of the spherical raceway surface 3a of the outer ring 3 is formed to be rougher than that of the raceway surface 2a of the inner ring 2. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

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

  In various industrial machines such as papermaking machines, machine tools, steel machines, and vehicle engines, self-aligning roller bearings are used as bearings for supporting rolls, rotating shafts, and the like. This self-aligning roller bearing can prevent the occurrence of abnormal loads and ensure a large radial load capacity because the contact state of the rollers with the bearing ring hardly changes even if the bearing ring is tilted due to mounting error or impact load. Has advantages.

When a negative skew occurs in the roller of such a self-aligning roller bearing, the axial load is amplified and the bearing life is shortened. For example, in the one described in Patent Document 1, in order to suppress the negative skew of the roller. Moreover, the roughness of the raceway surface of the outer ring is made rougher than the roughness of the raceway surface of the inner ring.
However, if the roughness of the outer raceway surface is simply made larger than that of the inner raceway surface, a negative skew that tilts the rollers to the inside of the bearing will occur, increasing the axial load and suppressing the negative skew. However, since the bearing life may be shortened, it is difficult to say that skew control has a decisive effect on extending the bearing life. Further, if the outer ring raceway surface is too rough, the outer ring raceway surface irregularities become larger than the oil film thickness, so that the state of lubrication deteriorates, and conversely, the service life tends to be short.

Therefore, in order to suppress the early peeling due to surface damage such as peeling and to extend the life of the self-aligning roller bearing, for example, in the ones described in Patent Documents 2 and 3, a gutter-like groove is formed on the raceway surface of the outer ring. The surface roughness Ra is 0.1 μm or more and 0.5 μm or less. The twill-like groove is a state in which two groove groups composed of a plurality of linear grooves parallel to each other intersect each other with a predetermined crossing angle to form a rhombus pattern.
Japanese Patent Publication No.57-61933 JP 2005-121199 A JP-A-2005-90615

However, in the thing of patent document 2, 3, the lifetime may not be enough depending on use conditions (especially under high load conditions), and the further performance improvement was desired.
Accordingly, an object of the present invention is to solve the above-described problems of the prior art and to provide a self-aligning roller bearing having a long life in which early peeling due to surface damage such as peeling is unlikely to occur.

  In order to solve the above problems, the present invention has the following configuration. That is, the self-aligning roller bearing of claim 1 according to the present invention has an inner ring having a double row raceway surface on the outer surface and a double row spherical raceway surface facing the raceway surface of the inner ring. An outer ring disposed on the outer side, and double-row spherical rollers disposed so as to be able to roll between the raceway surfaces of the two wheels, and the surface roughness in the axial direction and the circumferential direction of the raceway surface of the outer ring is In a self-aligning roller bearing that is rougher than the surface roughness of the inner ring raceway surface, the outer ring raceway surface is formed with fine grooves and has an axial and circumferential surface roughness Ra of 0.1 μm to 1 μm. A solid lubricant film is coated on the metal surface by mechanical energy, and the thickness of the solid lubricant film is 1/10 or more and 1/2 or less of the surface roughness Ra of the metal surface. To do.

  The self-aligning roller bearing according to claim 2 of the present invention includes an inner ring having a double row raceway surface on an outer surface and a double row spherical raceway surface facing the raceway surface of the inner ring. An outer ring disposed on the outer side, and double-row spherical rollers disposed so as to be able to roll between the raceway surfaces of the two wheels, and the surface roughness in the axial direction and the circumferential direction of the raceway surface of the outer ring is In a self-aligning roller bearing that is rougher than the surface roughness of the inner raceway surface, the outer raceway surface is formed with fine grooves and has an axial and circumferential surface roughness Ra of 0.1 μm or more and 1 μm or less. A solid lubricant film is coated on the metal surface by shot blasting of a solid lubricant powder, and the thickness of the solid lubricant film is 1/10 or more and 1/2 or less of the surface roughness Ra of the metal surface. It is characterized by that.

Furthermore, the self-aligning roller bearing according to claim 3 of the present invention is the self-aligning roller bearing according to claim 1 or 2, wherein the solid lubricant contains a base metal that is lower than iron. Features.
Furthermore, the self-aligning roller bearing according to claim 4 of the present invention is the self-aligning roller bearing according to claim 1 or 2, wherein the solid lubricant contains at least zinc.

  The self-aligning roller bearing of the present invention has a long life because it is difficult to cause early peeling due to surface damage such as peeling.

Embodiments of a self-aligning roller bearing according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a longitudinal sectional view showing the structure of an embodiment of a self-aligning roller bearing according to the present invention.
This self-aligning roller bearing 1 includes an inner ring 2, an outer ring 3, two rows of spherical rollers 4 disposed between the inner ring 2 and the outer ring 3, and an inner ring 2 and an outer ring 3. And a retainer 5 for holding the spherical roller 4, and a lubricant (not shown) is disposed in a space formed between the inner ring 2 and the outer ring 3. The inner ring 2, the outer ring 3, and the spherical roller 4 of the self-aligning roller bearing 1 are made of a metal material (hereinafter sometimes referred to as a base material) such as high carbon chromium bearing steel. Note that the cage 5 and the lubricant may not be provided.

On the outer peripheral surface of the inner ring 2, raceway surfaces 2a, 2a of two rows of spherical rollers 4 are formed, and the outer diameter of the inner ring 2 is formed larger at the center than at both ends in the width direction. Further, the inner peripheral surface of the outer ring 3 is a two-row spherical raceway surface 3 a, and this spherical raceway surface 3 a faces the raceway surfaces 2 a and 2 a of the inner ring 2.
The raceways 2a and 2a of the inner ring 2 are formed of a metal surface of the base material, and the surface roughness Ra is a general surface roughness Ra on the raceway surface of the rolling bearing in both the axial direction and the circumferential direction. (Usually 0.05 μm to 0.15 μm).

  On the other hand, the spherical raceway surface 3a of the outer ring 3 is formed by coating a metal surface of a base material with a solid lubricant film with mechanical energy. That is, the surface of the spherical surface 3a of the outer ring 3 is configured by coating the solid metal coating on the metal surface of the base material by a method such as shot blasting of the solid lubricant powder. As shown in FIG. 2, the metal surface is formed with twill-like fine grooves 10, and the surface roughness Ra (that is, the surface roughness Ra of the metal surface before being coated with the solid lubricant film). ) Is rougher than the raceway surfaces 2a and 2a of the inner ring 2 in both the axial direction and the circumferential direction, and is set to 0.1 μm or more and 1 μm or less (preferably 0.1 μm or more and 0.5 μm or less).

  Then, since it is necessary to prevent the concave portion of the fine groove 10 from being filled with the solid lubricant (see FIG. 3), the thickness of the solid lubricant film 11 coated on the metal surface is the surface roughness of the metal surface. It is necessary to make it 1/10 to 1/2 of Ra (see FIG. 4). For example, when the surface roughness Ra of the metal surface is 0.5 μm, the thickness of the solid lubricant film 11 is in the range of 0.05 μm or more and 0.25 μm.

Since such a solid lubricant film 11 is coated, the surface roughness Ra of the spherical raceway surface 3a after the metal surface is coated with the solid lubricant film 11 is also the track of the inner ring 2 in both the axial direction and the circumferential direction. Rougher than the surfaces 2a, 2a. Note that the solid lubricant film 11 may be coated not only on the surface of the outer ring 3 but also on the spherical raceway surface 3a as well as other portions.
Since the surface roughness Ra of the spherical raceway surface 3a of the outer ring 3 is rougher than the surface roughness Ra of the raceway surfaces 2a, 2a of the inner ring 2 in both the axial direction and the circumferential direction, the spherical roller bearing 1 is subject to surface damage such as peeling. Premature peeling due to is difficult to occur and has a long life. Further, since the spherical raceway surface 3a of the outer ring 3 includes the solid lubricant film 11, the solid lubricant film 11 functions as an extreme pressure agent when a high load is applied to the self-aligning roller bearing 1, Seizure and wear are suppressed.

  If the thickness of the solid lubricant film 11 is less than 1/10 of the surface roughness Ra of the metal surface, the above effects cannot be obtained sufficiently, and the self-aligning roller bearing 1 may have a short life. is there. On the other hand, when the thickness of the solid lubricant film 11 is more than 1/2 of the surface roughness Ra of the metal surface, the amount of solid lubricant present in the recesses of the fine grooves 10 increases, so that when a load is applied There is a possibility that stress toward the valley of the fine groove 10 is generated and the occurrence of damage such as cracks on the metal surface of the outer ring 3 may be promoted.

  In order to make such inconvenience less likely to occur, the thickness of the solid lubricant film 11 is preferably in the range of 1/10 to 1/3 of the surface roughness Ra of the metal surface. More preferably, it is in the range of 10 or more and 1/4 or less, and most preferably about 1/4 of the surface roughness Ra of the metal surface, which is 1/2 of the average height of the irregularities of the fine groove 10. However, in order to obtain a sufficient effect, the thickness of the solid lubricant film 11 is preferably 0.05 μm or more.

  As shown in FIG. 4, the solid lubricant film 11 is also coated in the vicinity of the apex of the uneven portion of the fine groove 10, but the apex portion of the peak is in contact with the mating surface. The solid lubricant film 11 covered in the vicinity of the apex of the part is peeled off by the initial wear (see FIG. 5). However, since the solid lubricant film 11 existing in a portion other than the vicinity of the peak portion of the peak portion (valley portion or the like) remains, a sufficient effect is obtained for the skew control, and there is no problem. The peeled solid lubricant film 11 acts as a lubricant for the self-aligning roller bearing 1.

Further, when an excessive load is applied or when the self-aligning roller bearing 1 is driven at an excessively high speed rotation, a portion near the apex of the uneven portion of the fine groove 10 is worn and scraped ( Since the solid lubricant film 11 remains as in the state of FIG. 5, there is no problem with the effect of skew control.
When a high load is applied to the self-aligning roller bearing 1, the portion near the top of the peak is elastically deformed and the portion covered with the solid lubricant film 11 is exposed on the contact surface with the mating surface. In addition, since the solid lubricant film 11 comes into contact with the mating surface, metal contact is prevented and peeling due to the surface starting point is suppressed.

  The kind of the solid lubricant film 11 is not particularly limited, but a base metal that is a base metal or at least a base metal, which is the main component of the metal material constituting the outer ring 3, is preferable. Moreover, it is not limited to what consists of a kind of metal, The mixture or alloy which consists of a some metal may be sufficient as long as it contains a base metal rather than iron. By coating the above film on the surface, even in an environment where rust is likely to occur (for example, when water enters), a base metal dissolves preferentially over iron (self-sacrificial rust prevention action), Rusting of the outer ring 3 is suppressed. Moreover, generation | occurrence | production of white peeling is also suppressed. Zinc, aluminum, bismuth, etc. are raised as a base metal rather than iron.

  Furthermore, since the solid lubricant film 11 is formed by utilizing mechanical energy, erosion and hydrogen embrittlement which are problems in chemical conversion treatment and plating, which are conventional film formation methods, do not occur. Further, the solid lubricant film 11 formed by utilizing mechanical energy is firmly adhered to the surface of the base material and hardly peeled off. As a method for forming the solid lubricant film 11 using mechanical energy, shot blasting or shot peening in which a solid lubricant powder is sprayed is preferable because the solid lubricant film 11 can be easily formed in a short time. Also, a method of adding a suitable medium to the solid lubricant powder and subjecting it to a mixing treatment such as ball milling or barrel treatment can be adopted as a method of forming the solid lubricant coating 11 using mechanical energy.

  The spraying direction when spraying the solid lubricant powder by shot blasting is not particularly limited, and may be sprayed perpendicular to the metal surface or from a direction inclined with respect to the metal surface. Alternatively, the solid lubricant film 11 may be formed by spraying from one direction, or the solid lubricant film 11 may be formed by spraying from multiple directions. For example, when sprayed from a direction inclined from the upstream side to the downstream side in the moving direction of the spherical roller 4 (a direction inclined from the lower side to the upper side in FIG. 2), the solid lubricant film 11 as shown in FIG. Is formed. In this case, the portion having the maximum film thickness is defined as the thickness of the solid lubricant film 11.

  In shot blasting, the solid lubricant powder may be injected using air, or may be injected using nitrogen or an inert gas. Further, the film forming method using mechanical energy represented by shot blasting also has a secondary effect that residual stress is generated in the base material. Furthermore, in order to obtain an effect similar to such a secondary effect, glass beads or SiC powder shot blast may be applied to the metal surface as a pretreatment. Furthermore, according to the method of forming a film using mechanical energy, it is not necessary to perform high-temperature exposure by an essential baking process in electroplating or the like.

  Furthermore, the method of forming the twill-like fine grooves 10 on the metal surface is not particularly limited, and examples thereof include a method using a grindstone as described below. After grinding the inner peripheral surface of the outer ring 3 by making the rotation axis of the grinding wheel parallel to the central axis of the outer ring 3 and swinging the grinding wheel in the circumferential direction, another grinding wheel having a large roughness is rotated while rotating the outer ring 3. Superfinishing is performed by swinging in the axial direction of the outer ring 3. Then, grinding marks (fine grooves 10) generated on the inner peripheral surface of the outer ring 3 have a cross-like shape as shown in FIG. 2, thereby reducing variations in roughness.

  Further, each member such as the inner ring 2, the outer ring 3, and the spherical roller 4 constituting the self-aligning roller bearing 1 does not need to be formed of the same kind of metal material. For example, the spherical roller 4, the inner ring 2, and the outer ring 3 May be different steel types. Furthermore, the self-aligning roller bearing 1 may include a sealing device and other attached members.

It is sectional drawing which shows the structure of one Embodiment of the self-aligning roller bearing which concerns on this invention. It is a conceptual diagram explaining the twill-like fine groove | channel formed in the metal surface. It is sectional drawing explaining the state with which the recessed part of the fine groove was satisfy | filled with the solid lubricant. It is sectional drawing which shows the solid lubricant film coat | covered on the metal surface. It is sectional drawing explaining the state which the solid lubricant film coat | covered by the vertex vicinity part of the peak part peeled. It is sectional drawing explaining the state by which the peak vicinity part of the peak part was worn out and was shaved. It is sectional drawing which shows the solid lubricant film formed by spraying the powder of a solid lubricant from the direction inclined with respect to the metal surface.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Self-aligning roller bearing 2 Inner ring 2a Raceway surface 3 Outer ring 3a Spherical raceway surface 4 Spherical roller 10 Fine groove 11 Solid lubricant film

Claims (4)

An inner ring having a double-row raceway surface on the outer surface, an outer ring having a double-row integral spherical raceway surface facing the raceway surface of the inner ring, and an outer ring disposed on the outer side of the inner ring; A self-aligning roller bearing, wherein the outer ring raceway surface has a surface roughness in the axial direction and the circumferential direction that is coarser than the surface roughness of the inner ring raceway surface. ,
The raceway surface of the outer ring is formed by coating a solid lubricant film with mechanical energy on a metal surface in which fine grooves are formed and the surface roughness Ra in the axial direction and the circumferential direction is 0.1 μm or more and 1 μm or less, A self-aligning roller bearing, wherein the thickness of the solid lubricant film is 1/10 or more and 1/2 or less of the surface roughness Ra of the metal surface. An inner ring having a double-row raceway surface on the outer surface, an outer ring having a double-row integral spherical raceway surface facing the raceway surface of the inner ring, and an outer ring disposed on the outer side of the inner ring; A self-aligning roller bearing, wherein the outer ring raceway surface has a surface roughness in the axial direction and the circumferential direction that is coarser than the surface roughness of the inner ring raceway surface. ,
The outer ring raceway surface is coated with a solid lubricant film by shot blasting of a solid lubricant powder on a metal surface in which fine grooves are formed and the surface roughness Ra in the axial and circumferential directions is 0.1 μm or more and 1 μm or less. The self-aligning roller bearing is characterized in that the thickness of the solid lubricant film is 1/10 or more and 1/2 or less of the surface roughness Ra of the metal surface.   The self-aligning roller bearing according to claim 1 or 2, wherein the solid lubricant contains a metal that is baser than iron.   The self-aligning roller bearing according to claim 1 or 2, wherein the solid lubricant contains at least zinc.

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