JP2005155838A - Roller bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a roller bearing with a bearing ring and a guard forming member separate from the bearing ring, having longer service life, superior wear resistance, reduced torque and improved rotating performance. <P>SOLUTION: M50 is adopted as a material for a guard body 6, and the surface of the guard body 6 on the bearing center side is covered with a DLC film 10 having a HV of 1000 or more and a film thickness of 1-3 μm. The guard forming member 5 and a conical roller 3 are so formed as to satisfy conditions that the arithmetic average roughness of a radially outward end face 8 of the DLC film 10 on the side of the conical roller 3 is 0.04 μm or less and to satisfy a relationship of R2/R1=1.2 to 2.5 between a radius of curvature R1 of a contact portion of a large end face 9 of the conical roller 3 contacting the DLC film 10 in a plane including the center axis of the conical roller 3 and a radius of curvature R2 of a contact portion of the DLC film contacting the large end face 9 of the conical roller 3 in a plane including a center axis 4 of an inner ring 1. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a roller bearing.

  Conventionally, as a roller bearing, for example, as described in Japanese Patent Application Laid-Open No. 2001-82466 (Patent Document 1), a bearing ring and a flange forming member with which the end face of the roller contacts are different members. There is.

  In the roller bearing in which the bearing ring and the heel forming member are configured as separate members, the heel forming member may be a high-carbon chromium bearing steel (SUJ2 or the like) that has been normally quenched or a carburized and quenched steel that has been carburized and quenched. (A SAE5120 or the like) and the like, and a roller body made of a material used in a rolling bearing, and a hard film that covers the roller-side end surface of the roller body and on which the roller end surface slides.

  In the roller bearing, the roller side end surface of the collar body is coated with a hard coating to reduce the friction between the roller end surface and the portion of the hard coating on which the roller end surface slides. In addition, the seizure of the end surface of the roller and the portion where the end surface of the roller in the hard coating slides is suppressed, and the friction torque caused by this friction is reduced to reduce the operating cost of the roller bearing.

However, the roller bearing requires a heat treatment at 200 ° C. to 500 ° C. that exceeds the tempering temperature of the material used in the rolling bearing when the hard coating is applied to the collar body. Tempering of the material used in the rolling bearing, which is the material that constitutes the main body, causes the heel body to soften or become distorted, resulting in dimensional accuracy. There is a problem in that the rotational performance is deteriorated due to a decrease, an increase in torque, vibration, and the like.
JP 2001-82466 A

  SUMMARY OF THE INVENTION An object of the present invention is to provide a bearing ring and a flange-forming member that is a separate member from the bearing ring, have a long service life, excellent wear resistance, and can reduce torque and excel in rotational performance. It is to provide a roller bearing.

  In order to solve the above problems, a roller bearing of the present invention is an outer ring, an inner ring, a plurality of rollers disposed between the outer ring and the inner ring, the outer ring and the inner ring are separate members, A roller bearing comprising a flange forming member that contacts an end surface of the roller, wherein the flange forming member covers a flange main body made of heat-resistant steel and at least a part of the flange main body, and the end surface of the roller is It includes a sliding hard coating.

  In this specification, the heat-resistant steel is defined as steel having a tempering temperature higher than 500 ° C.

  According to the above invention, the heat-resistant steel having a tempering temperature higher than 500 ° C. is adopted as the material of the cocoon body. Therefore, the heat treatment at 200 ° C. to 500 ° C. when the cocoon body is coated with the hard coating, Tempering does not occur, and the hardness of the heel body is not softened, or the heel body is distorted and the dimensional accuracy of the heel body is changed, and the vicinity of the joint portion between the heel forming member and the raceway is not rattled. Therefore, since the material strength of the heel body does not decrease, the life of the heel forming member can be extended and the occurrence of vibrations due to rattling can be suppressed and the rotational performance of the roller bearing can be improved. Can do.

  Further, according to the invention, since the collar body is covered with the hard coating, the frictional force generated between the end surface of the roller and the portion where the end surface of the roller in the hard coating slides is reduced. Thus, the torque resulting from this frictional force can be reduced, the operating cost can be reduced, and seizure of the end face of the roller and the portion of the hard coating where the end face of the roller slides can be suppressed.

  Further, in the roller bearing of one embodiment, the radius of curvature in a plane including the central axis of the roller at the contact portion of the end surface of the roller that contacts the hard coating is R1, and the hard coating of the hard coating that contacts the end surface of the roller is used. When the radius of curvature in the plane including the central axis of the inner ring of the contact portion is R2, R2 / R1 = 1.2 to 2.5, and the arithmetic average roughness of the contact portion of the hard coating is It is characterized by being 0.04 μm or less.

  According to the embodiment, since R2 / R1 is set to R2 / R1 = 1.2 to 2.5, an oil film is formed between the contact portion on the end face of the roller and the contact portion of the hard coating. A capability can be improved and the contact surface pressure between the said contact part of the end surface of the said roller and the said contact part of the said hard film can be made small. In addition, since the arithmetic average roughness (Ra) of the contact portion of the hard coating is set to 0.04 μm or less, the frictional force between the contact portion of the end surface of the roller and the contact portion of the hard coating is reduced. It can be remarkably reduced. Therefore, torque can be further reduced, and seizure of the contact portion on the end face of the roller and the contact portion of the hard coating can be remarkably suppressed.

  When R2 / R1 is larger than 2.5, the oil film forming ability decreases, the contact surface pressure increases, the torque increases, and seizure resistance also decreases. On the other hand, if R2 / R1 is smaller than 1.2, the contact area becomes too large and protrudes from the collar surface, and edge load occurs. Although the above-mentioned effect can be obtained by setting R2 / R1 = 1.2 to 2.5, it is preferable to set R2 / R1 = 1.5 to 2.0.

  Moreover, the roller bearing of one embodiment is characterized in that the hard film is a diamond-like carbon (DLC) film having a Vickers hardness (HV) of 1000 or more and a film thickness of 1 to 3 μm.

  According to the above embodiment, since the Vickers hardness of the DLC film is set as high as 1000 or more, it has sufficient wear resistance and a low friction coefficient. In addition, since the film thickness of the DLC film is set to 1 to 3 μm, it is possible to suppress early wear and peeling of the film, improve the durability of the film, and maintain an appropriate film for a long time. That is, if the film thickness is smaller than 1 μm, the base surface may be exposed at an early stage due to abrasion of the film. On the other hand, if the film thickness is larger than 3 μm, the adhesion between the film and the base surface is lowered, and the film may be peeled off. According to the above embodiment, since the film thickness of the DLC film is set to 1 to 3 μm, the frictional force generated between the contact portion of the end face of the roller and the contact portion of the hard coating can be further reduced. Torque can be further reduced, and seizure of the contact portion of the end face of the roller and the contact portion of the hard coating can be reliably suppressed.

  Moreover, the roller bearing of one embodiment is characterized in that the heat-resistant steel is M50.

  The M50 refers to M50 steel defined by AISI (American Iron and Steel Institute).

  According to the above embodiment, since the heat-resistant steel is M50 having a very high tempering temperature, it is possible to further reduce the decrease in hardness when exposed to the high temperature of the cocoon body. Stability can be further improved.

  According to the roller bearing of the present invention, since the heat-resistant steel having a high tempering temperature is adopted as the material of the heel body, the tempering of the heel body occurs in the heat treatment when the heel body is coated with the hard coating. Thus, the hardness of the heel body is not softened, and the heel body is not distorted and the dimensional accuracy of the heel body is changed, so that the vicinity of the joint between the heel forming member and the race is not rattled. Therefore, since the material strength of the cocoon body does not decrease, the life of the cocoon forming member can be extended, and the occurrence of vibration and the like due to rattling can be suppressed and the rotation performance can be improved. Moreover, there is no need to perform additional machining on the collar body after the hard coating treatment, and the processing cost can be reduced.

  Further, according to the invention, since the collar body is covered with the hard coating, the frictional force generated between the end surface of the roller and the portion where the end surface of the roller in the hard coating slides is reduced. Thus, the torque resulting from this frictional force can be reduced, the operating cost can be reduced, and seizure of the end face of the roller and the portion of the hard coating where the end face of the roller slides can be suppressed.

  Hereinafter, the present invention will be described in detail with reference to the drawings.

(First embodiment)
FIG. 1 is an axial sectional view of a tapered roller bearing according to a first embodiment of the roller bearing of the present invention.

  This tapered roller bearing includes a carburized and quenched carburized steel (SAE5120) inner ring 1, a carburized and hardened carburized steel (SAE5120) outer ring 2, and a normally quenched high carbon chrome bearing. A plurality of tapered rollers 3 made of steel (SUJ2) and a flange forming member 5 are provided.

  The plurality of tapered rollers 3 are arranged between the outer peripheral conical surface of the inner ring 1 and the inner peripheral conical surface of the outer ring 2 with a certain interval in the circumferential direction while being held by the cage 7. .

  The flange forming member 5 substantially covers the entire surface of the flange main body 6 made of M50 as an example of heat-resistant steel and the bearing center side (the inner ring 1 and the tapered roller 3 side) of the flange main body 6, and the tapered roller 3 And a diamond-like carbon film (DLC film) 10 as an example of a hard film including a portion with which the large end surface 9 contacts. The DLC film 10 has a Vickers hardness (HV) of 1000 or more and a film thickness of 1 to 3 μm.

  The surface shape of the DLC film 10 on the bearing center side (inner ring 1 and tapered roller 3 side) has a shape substantially corresponding to the shape of the end surface (end face and end outer peripheral face) of the inner ring 1 on the large diameter side. The flange forming member 5 is disposed around the adjacent portion on the large diameter side of the inner ring 1 so that the surface on the bearing center side of the DLC film 10 is fitted into the surface of the end portion on the large diameter side of the inner ring 1. Yes. Further, the flange forming member 5 has an end face 8 that supports the radially inward portion of the end face 9 on the large diameter side of the tapered roller 3 on the outer side in the radial direction. The end surface 8 has an arithmetic average roughness (Ra) set to 0.04 μm or less, and is radially outward from the outer peripheral surface of the inner ring 1 substantially along the normal direction of the outer peripheral surface of the end portion. It extends to. A substantially central portion of the end surface 8 in the radial direction is a contact portion (a sliding portion on which the large end surface 9 of the tapered roller 3 slides) in contact with the large end surface 9 of the tapered roller 3.

  Further, FIG. 2 which is a partial schematic view around the tapered roller 3 in FIG. 1 shows a curvature in a plane including the central axis of the tapered roller 3 in the contact portion of the large end surface 9 of the tapered roller 3 which is in contact with the DLC film 10 indicated by R1. The ratio of the radius of curvature R2 / R1 in the plane including the center axis 4 of the inner ring 1 (the center axis of the roller bearing) of the contact portion of the DLC film 10 in contact with the large end surface 9 of the tapered roller 3 indicated by R2 in FIG. Is set to R2 / R1 = 1.2 to 2.5. In FIG. 2, the radius of curvature R1 and the radius of curvature R2 are drawn exaggerated more than actual.

  According to the tapered roller bearing, since the material of the heel body 6 is M50, which is an example of heat-resistant steel having a tempering temperature higher than 500 ° C., 200 ° C. to 500 ° C. when the heel body 6 is coated with the DLC film 10 is used. With the heat treatment at ℃, the hardness of the heel body 6 is softened by tempering, or the heel body 6 is distorted and the dimensional accuracy of the heel body 6 changes, and the vicinity of the joint between the heel forming member 5 and the inner ring 1 is rattled I won't follow you. Therefore, since the material strength of the heel body 6 does not decrease, the life of the heel forming member 5 can be extended, and the occurrence of vibrations and the like due to rattling can be suppressed and the rotation performance can be improved. .

  Further, according to the tapered roller bearing, the collar body 6 is covered with the DLC film 10 which is an example of a hard coating, so the large end surface 9 of the tapered roller 3 and the DLC film in contact with the large end surface 9. The frictional force generated between the end face 8 and the contact portion of the end face 8 can be reduced, the torque resulting from this frictional force can be reduced, the operating cost can be reduced, and the large end face 9 of the tapered roller 3 and the DLC film 10 can be reduced. The seizure of the contact portion of the tapered roller 3 on the end face 8 can be suppressed.

  Further, according to the tapered roller bearing, since R2 / R1 is set to R2 / R1 = 1.2 to 2.5, the large end surface 9 of the tapered roller 3 and the contact portion of the tapered roller 3 on the end surface 8 The contact surface pressure between the large end surface 9 of the tapered roller 3 and the contact portion of the tapered roller 3 on the end surface 8 can be reduced. In general, this effect is particularly important for improving the performance of a tapered roller bearing when used with a large axial load. Further, since the arithmetic average roughness (Ra) of the end face 8 is set to 0.04 μm or less, the frictional force between the large end face 9 of the tapered roller 3 and the contact portion of the end face 8 with the tapered roller 3 can be reduced. Therefore, torque can be further reduced and seizure of the contact portion of the tapered roller 3 on the large end surface 9 and the end surface 8 of the tapered roller 3 can be further suppressed.

  Further, according to the tapered roller bearing, since the Vickers hardness of the DLC film 10 is set as high as 1000 or more, it has sufficient abrasion resistance and a friction coefficient becomes small. Moreover, since the film thickness of the DLC film 10 is set to 1 to 3 μm, early wear and delamination of the DLC film 10 can be suppressed, durability of the DLC film 10 can be improved, and an appropriate DLC film 10 for a long time can be obtained. Can be maintained. That is, if the thickness of the DLC film is smaller than 1 μm, the base surface may be exposed at an early stage due to wear of the DLC film. On the other hand, if the thickness of the DLC film is larger than 3 μm, the adhesion between the DLC film and the base surface is lowered, and the DLC film may be peeled off. According to the tapered roller bearing, since the thickness of the DLC film 10 is set to 1 to 3 μm, the frictional force generated between the large end surface 9 and the end surface 8 of the tapered roller 3 can be further reduced, and the torque can be reduced. Further, the seizure of the large end surface 9 and the end surface 8 of the tapered roller 3 can be reliably suppressed.

  Further, according to the tapered roller bearing, since the cocoon body 6 made of M50 having a very high tempering temperature is adopted, the decrease in hardness when the cocoon body 6 is exposed to a high temperature can be further reduced. Stability can be further improved.

In the above tapered roller bearing, the DLC film 10 is employed as the hard coating. However, in the roller bearing of the present invention, the hard coating is a carbide hard coating such as TiC, a nitride hard coating such as CrN, TiN or TiAlN, carbonitride hard coating such as TiCN, _Al 2 _{O 3} such as an oxide hard coating or, may be employed a hard coating such as WC / C (tungsten carbide carbon).

  In the tapered roller bearing, carburized and hardened carburized steel (SAE5120) is used as the material for the inner ring 1 and the outer ring 2, but in the roller bearing according to the present invention, normal hardening is used as the material for the inner ring and the outer ring. Materials used in rolling bearings other than carburized and quenched carburized and hardened steel (SAE5120), such as high carbon chromium bearing steel (SUJ2) that has been subjected to carburizing, may be employed.

  Further, in the tapered roller bearing, the entire surface on the bearing center side of the collar body 6 is covered with the substantially DLC film 10, but in the roller bearing of the present invention, the entire surface on the bearing center side of the collar body is coated with a hard coating. It is only necessary to cover at least part of the bearing center side of the collar body so that the rollers do not directly contact the collar body.

  Further, in the above tapered roller bearing, M50 is adopted as the material of the flange main body 6. However, in the roller bearing of the present invention, the material of the flange main body may be a heat-resistant steel defined by a steel having a tempering temperature higher than 500 ° C. Anything can be used.

  In the tapered roller bearing, the arithmetic average roughness of the entire end face 8 is set to 0.04 μm or less, but the arithmetic average roughness of the hard coating portion on which the tapered rollers slide is set to 0.04 μm or less. In this case, the same effect as that obtained when the arithmetic average roughness of the front surface of the end face 8 is set to 0.04 μm or less can be obtained.

(Second Embodiment)
FIG. 3 is an axial sectional view of a cylindrical roller bearing of a second embodiment of the roller bearing of the present invention.

  The cylindrical roller bearing includes a carburized and hardened inner ring 31 made of carburized steel (SAE5120), a carburized and hardened carburized steel (SAE5120) outer ring 32, and the periphery of one end in the axial direction of the outer ring 32. The first heel forming member 33 disposed on the outer ring 32, the second heel forming member 34 disposed around the other axial end of the outer ring 32, and the axial dimension of the outer ring 32 is substantially the same as the axial dimension. And a cylindrical roller 35 made of high-carbon chromium bearing steel (SUJ2), which is normally quenched.

  A plurality of the cylindrical rollers 35 are arranged between the outer peripheral cylindrical surface of the inner ring 31 and the inner peripheral cylindrical surface of the outer ring 32 at a substantially equal interval in the circumferential direction while being held by a cage 38. Further, both end surfaces 40, 41 in the axial direction of the outer ring 32 are present in a plane perpendicular to the central axis 39 of the inner ring 31.

  The first and second flange forming members 33 and 34 are disposed so as to cover the entire surface of the flange main bodies 56 and 57 disposed on the outer side in the axial direction and the end surfaces of the flange main bodies 56 and 57 on the cylindrical roller 35 side. DLC films 50 and 51 as an example of the hard coating to be provided. The DLC films 50 and 51 have a Vickers hardness of 1000 or more and a film thickness of 1 to 3 μm.

  The first and second flange forming members 33 and 34 are substantially the same cylindrical members, and the axial thickness is greater than the radial thickness (thickness from the inner peripheral surface to the outer peripheral surface). Is also thinner. The radial thickness of the first and second flange forming members 33 and 34 is greater than the radial thickness (thickness from the inner peripheral surface to the outer peripheral surface) of the outer ring 32. The inner portions of the first and second ridge forming members 33 and 34 in the radial direction from the outer rings 32 are ridges. The radially inner portions of the end faces 48, 49 of the first and second flange forming members 33, 34 on the cylindrical roller 35 side in the radial direction from both end faces 40, 41 of the outer ring 32 are both end faces 45 of the cylindrical roller 35. 46 are supported. The first and second flange forming members 33 and 34 are disposed substantially symmetrically on both sides of the outer ring 32 with the end faces 48 and 49 being in contact with both end faces 40 and 41 of the outer ring 32. . The first flange forming member 33 and the outer ring 32 are appropriately coupled and fixed by a well-known method such as coupling with a bolt (not shown). Similarly, the second flange forming member 34 and the outer ring 32 are also connected and fixed appropriately by a well-known method such as connecting with a bolt (not shown).

  Also in this cylindrical roller bearing, the arithmetic average roughness of the end faces 48 and 49 of the first and second flange forming members 33 and 34 is set to 0.04 μm or less.

  Further, the radius of curvature in a plane including the central axis of the cylindrical roller 35 at the contact portion of the end surfaces 45 and 46 of the cylindrical roller 35 that contacts the DLC films 50 and 51 is R1, and the end surfaces 45 and 46 of the cylindrical roller 35 are in contact with each other. When the radius of curvature in the plane including the central axis 39 of the inner ring 31 at the contact portion of the DLC films 50 and 51 is R2, R2 / R1 is set to 1.2 to 2.5.

  The cylindrical roller bearing of the second embodiment is essentially different from the tapered roller bearing of the first embodiment in that there are two ridge forming members 33 and 34, and there is only one ridge forming member 5. From this, the cylindrical roller bearing of the second embodiment has all the operational effects of the tapered roller bearing of the first embodiment, and the tapered roller of the first embodiment is added to the cylindrical roller bearing. It goes without saying that the modification examples given for the bearing can be applied as they are.

It is sectional drawing of the axial direction of the tapered roller bearing of 1st Embodiment of this invention. FIG. 2 is an enlarged schematic view around a tapered roller in FIG. 1. It is sectional drawing of the axial direction of the cylindrical roller bearing of 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,31 Inner ring | wheel 2,32 Outer ring | wheel 3 Tapered roller 4,39 Center axis | shaft of an inner ring | wheel 5 鍔 formation member 6,56,57 鍔 main body 8 End surface 9 Large end surface of a tapered roller 10,50,51 DLC film 33 1st ridge formation Member 34 Second flange forming member 35 Cylindrical roller 45, 46 End face 48 of cylindrical roller 48 End face on the inner side in the axial direction of the first hook forming member 49 End face on the inner side in the axial direction of the second hook forming member R1 DLC film and Radius of curvature in the plane including the central axis of the tapered roller at the contact portion of the large end surface of the tapered roller in contact R2 Radius of curvature in the plane including the central axis of the inner ring of the contact portion of the DLC film in contact with the large end surface of the tapered roller

Claims (4)

A roller provided with an outer ring, an inner ring, a plurality of rollers disposed between the outer ring and the inner ring, and a flange forming member that is a separate member from the outer ring and the inner ring and that contacts the end face of the roller. A bearing,
The roller bearing includes a roller main body made of heat-resistant steel, and a hard coating that covers at least a part of the roller main body and on which an end surface of the roller slides. The roller bearing according to claim 1,
The radius of curvature in the plane including the central axis of the roller of the contact portion of the end surface of the roller that contacts the hard coating is R1, and includes the central axis of the inner ring of the contact portion of the hard coating that contacts the end surface of the roller. When the radius of curvature in the plane is R2,
R2 / R1 = 1.2 to 2.5,
And the roller bearing characterized by the arithmetic mean roughness of the said contact part of the said hard film being 0.04 micrometer or less. In the roller bearing according to claim 1 or 2,
2. The roller bearing according to claim 1, wherein the hard film is a diamond-like carbon film having a Vickers hardness of 1000 or more and a film thickness of 1 to 3 μm. In the roller bearing according to any one of claims 1 to 3,
The heat resistant steel is M50, a roller bearing.

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