JP2020143725A - Rolling device and rolling bearing - Google Patents

Abstract

To provide a rolling device and a rolling bearing without using a special barrel polishing process and a treatment solution of high environmental load.SOLUTION: A rolling device includes first rolling components 11, 12 and a second rolling component 13. The second rolling component 13 is kept into contact with the first rolling components 11, 12. Rockwell hardness of surfaces 11A, 12A of the first rolling portions as rolling portions of the first rolling components 11, 12 is lower than Rockwell hardness of a surface 13A of a second rolling portion as a rolling portion of the second rolling component 13. The Rockwell hardness of the surfaces 11A, 12A of the first rolling portions is 62 HRC or less. The surfaces 11A, 12A of the first rolling portion have such hardness of the surface layer of the first rolling portion that a residual displacement amount after removal of load measured by a nano-indentation method is 548 nm or more when a maximum push-in load is 100 μN.SELECTED DRAWING: Figure 2

Description

The present invention relates to rolling devices and rolling bearings, and more particularly to rolling devices and rolling bearings including first and second rolling components.

When rolling devices such as rolling bearings are used in an environment where oil film formation is insufficient due to poor lubrication of the rolling parts, surface damage such as peeling and seizure and peeling caused by this surface damage will roll. It occurs on the surface of moving parts. As a result, the life of the rolling element is shortened. For example, in the paper "Effect of lubrication on the tired life of roller bearings" (Non-Patent Document 1), an oil film parameter Λ indicating the severity of the lubrication state between the inner and outer rings of a rolling bearing and a rolling element is about 1. It is stated that the life of the rolling bearing is extended under the condition of .2 or more, but the life of the rolling bearing is shortened because the surface-origin type peeling occurs at the rolling part under the condition of the oil film parameter Λ of 1.2 or less. Has been done.

Therefore, it is effective to increase the value of the oil film parameter Λ as a countermeasure against surface damage of the rolling portion. As a method of increasing the value of the oil film parameter Λ, there are a method of improving the oil film forming ability and a method of improving the surface roughness.

As a method for improving the oil film forming ability, for example, Japanese Patent Application Laid-Open No. 4-265480 (Patent Document 1) specifies a standard for a specific surface roughness parameter for the inner and outer rings of a needle roller bearing or a rolling portion as a rolling element. A method of improving the oil film forming ability at a rolling portion by forming a minute dent to achieve is disclosed.

As a method for improving the surface roughness, for example, there is a method of reducing the surface roughness of the rolling portion by super-finishing, barrel polishing, burnishing, or the like. In addition, for example, Japanese Patent Application Laid-Open No. 2016-196958 (Patent Document 2) describes that surface damage of the rolling portion is suppressed by promoting familiarization of the surface roughness of the rolling portion during operation, and the life of the rolling bearing is maintained. A rolling device that lengthens the bearing is described. Japanese Unexamined Patent Publication No. 2016-196958 uses a black dyeing treatment as a method for promoting the familiarization of the surface roughness of the rolling portion.

Japanese Unexamined Patent Publication No. 4-265480 Japanese Unexamined Patent Publication No. 2016-196958

Hirotoshi Takada, Susumu Suzuki, Etsuo Maeda, "Effect of Lubrication on Tired Life of Roller Bearings", NSK Bearing Journal No. 642, p. 7-13

In Japanese Patent Application Laid-Open No. 4-265480, minute dents are formed on the surface of the rolling portion by special barrel polishing. Therefore, there is a risk of scratches due to contact between the treated members during barrel polishing. Further, in Japanese Patent Application Laid-Open No. 4-265480, there is a problem that minute dents cannot be formed by barrel polishing depending on the shape of the rolling portion. Further, according to Japanese Patent Application Laid-Open No. 4-265480, there is a problem that the processing process is complicated because special barrel polishing is required.

Next, the black dyeing treatment disclosed in JP-A-2016-196958 is carried out by a method in which the treatment member is immersed in a treatment liquid containing a strong alkali heated to about 140 ° C., particularly sodium hydroxide as a main component. Be done. However, the components of this treatment liquid correspond to poisonous and deleterious substances, and it is difficult to ensure the safety of treatment workers. In addition, the treatment liquid has a high environmental load. Further, since the treatment liquid consumes a large amount of energy to maintain the high temperature of about 140 ° C., there is a concern about the operating cost of the treatment line.

The present invention has been made in view of the above problems. An object of the present invention is to provide a rolling device and a rolling bearing without using a special barrel polishing process and a treatment liquid having a high environmental load.

A rolling device according to the present disclosure includes a first rolling component and a second rolling component. The second rolling component comes into contact with the first rolling component. The Rockwell hardness of the surface of the first rolling portion, which is the rolling portion of the first rolling component, is higher than the Rockwell hardness of the surface of the second rolling portion, which is the rolling portion of the second rolling component. Low. The Rockwell hardness of the surface of the first rolling portion is 62 HRC or less. The surface of the first rolling portion has a residual displacement amount after unloading when the hardness of the surface layer of the first rolling portion is measured by the nanoindentation method, which is 548 nm or more when the maximum pushing load is 100 μN. is there.

The rolling bearing according to the present disclosure is composed of the above-mentioned rolling device. The rolling bearing includes an outer ring, an inner ring, and a plurality of rolling elements. The outer ring has an outer ring raceway surface on the inner peripheral surface. The inner ring has an inner ring raceway surface on the outer peripheral surface. The plurality of rolling elements roll between the outer ring raceway surface and the inner ring raceway surface. The outer ring and the inner ring consist of a first rolling component. The rolling element comprises a second rolling component.

The rolling bearing according to the present disclosure is composed of the above-mentioned rolling device. The rolling bearing includes an outer ring, an inner ring, and a plurality of rolling elements. The outer ring has an outer ring raceway surface on the inner peripheral surface. The inner ring has an inner ring raceway surface on the outer peripheral surface. The plurality of rolling elements roll between the outer ring raceway surface and the inner ring raceway surface. The outer ring and inner ring consist of a second rolling component. The rolling element comprises a first rolling component.

The combination of the first rolling component and the second rolling component as described above makes it possible to provide a rolling device and a rolling bearing without using a special barrel polishing process and a treatment liquid having a high environmental load.

It is schematic cross-sectional view which shows the structure of the deep groove ball bearing in one Embodiment of this invention. It is an enlarged view which shows the structure of P part of FIG. It is the schematic which shows the structure of the two-cylindrical tester in an Example. It is a graph which shows typically the relationship between the depth which a microindenter is pushed into the measurement object in the nanoindentation method, and the load applied when it is pushed. Rockwell hardness of the end face of the driving side test piece D2 other than the rolling part before the rolling fatigue test, and the radius of curvature of the tip of the protruding part on the surface of the rolling part of the driving side test piece D2 after the rolling fatigue test. It is a graph which shows the relationship with the average value β of. The amount of residual displacement after unloading when the hardness of the surface layer of the end face other than the rolling part of the driving side test piece D2 before the rolling fatigue test is measured by the nanoindentation method, and the rolling of the driving side test piece D2. It is a graph which shows the relationship with the change amount before and after a rolling fatigue test of the standard deviation σ ^* of the apex height of a protrusion on the surface of a part. The relationship between the value of σ ^* / β on the surface of the rolling part of the driving side test piece D2 after the rolling fatigue test and the residual stress on the surface of the rolling part of the driven side test piece F2 after the rolling fatigue test. It is a graph which shows.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
(Embodiment 1)
Hereinafter, a configuration of a rolling bearing as an example of a rolling device according to an embodiment of the present invention will be described. Further, in the present embodiment, a deep groove ball bearing will be described as an example of a rolling bearing.

FIG. 1 is a schematic cross-sectional view showing the configuration of a deep groove ball bearing according to an embodiment of the present invention. FIG. 2 is an enlarged view showing the configuration of the P portion of FIG. With reference to FIG. 1, the deep groove ball bearing 1 of the present embodiment is arranged between the annular outer ring 11, the annular inner ring 12 arranged inside the outer ring 11, and the outer ring 11 and the inner ring 12. It includes a plurality of balls 13 as rolling elements held in the annular cage 14. The outer ring 11 has an outer ring raceway surface 11A on the inner peripheral surface. The inner ring 12 has an inner ring raceway surface 12A on the outer peripheral surface. That is, the outer ring raceway surface 11A is formed on the inner peripheral surface of the outer ring 11, and the inner ring raceway surface 12A is formed on the outer peripheral surface of the inner ring 12. The outer ring 11 and the inner ring 12 are arranged so that the outer ring raceway surface 11A and the inner ring raceway surface 12A face each other.

Further, the plurality of balls 13 are configured to roll between the outer ring raceway surface 11A and the inner ring raceway surface 12A. The plurality of balls 13 are in contact with the outer ring raceway surface 11A and the inner ring raceway surface 12A on the ball raceway surface 13A as the raceway surface of the ball 13, and are arranged by the cage 14 at a predetermined pitch in the circumferential direction. It is held freely on an annular orbit. Further, in the ball 13, the entire surface thereof is the ball track surface 13A. With the above configuration, the outer ring 11 and the inner ring 12 of the deep groove ball bearing 1 can rotate relative to each other.

A grease composition (not shown) is sealed in a space sandwiched between the outer ring 11 and the inner ring 12, more specifically, a space sandwiched between the outer ring raceway surface 11A and the inner ring raceway surface 12A. An oil film is formed between each of the outer ring 11 and the inner ring 12 and the ball 13 by this grease composition.

The outer ring 11, the inner ring 12, and the ball 13 as rolling components constituting the deep groove ball bearing 1 will be described with reference to FIG. The ball 13 as the second rolling component is in contact with each of the outer ring 11 and the inner ring 12 as the first rolling component. The outer ring 11, the inner ring 12, and the ball 13 are all made of, for example, high carbon chromium bearing steel, and are particularly preferably made of JIS standard SUJ2, but are not limited thereto.

The Rockwell hardness of the surface of the first rolling portion, which is the rolling portion of each of the outer ring 11 and the inner ring 12, is the surface of the second rolling portion, which is the rolling portion of the ball 13, that is, the raceway surface (ball raceway surface 13A). It is lower than the Rockwell hardness of. The Rockwell hardness of each of the outer ring 11 and the inner ring 12 is preferably 0.5 or more lower than the Rockwell hardness of the ball 13. The Rockwell hardness of the surface of the first rolling portion, which is the rolling portion of the outer ring 11 and the inner ring 12, that is, the outer ring raceway surface 11A and the inner ring raceway surface 12A is 62 HRC or less.

The surface of the first rolling portion, which is the rolling portion of the outer ring 11 and the inner ring 12, has a residual displacement amount after unloading when the hardness of the surface layer of the first rolling portion is measured by the nanoindentation method. When the maximum pushing load at the time of the measurement is 100 μN, it is 548 nm or more. However, the residual displacement amount after unloading is preferably 602 nm or more when the maximum pushing load at the time of the measurement is 100 μN. More specifically, the surface of the first rolling portion has a maximum pushing load of 100 μN and a residual displacement amount (hf) of 548 nm or more after unloading when the hardness is measured by the nanoindentation method using a Berkovich indenter (hf). It has a hardness or Young's modulus such that it is more preferably 602 nm or more). The surface layer of the first rolling portion here means, for example, a region within 5 μm in the depth direction from the surface of the first rolling portion.

In the deep groove ball bearing 1 of the present embodiment, the arithmetic mean surface roughness of the surface of the first rolling portion and the surface of the second rolling portion is preferably 0.20 μm or less.

In the deep groove ball bearing 1 of the present embodiment, it is preferable that the surface of the first rolling portion is finished by either grinding or polishing using a rotary grindstone. In other words, the surface of the first rolling portion in the deep groove ball bearing 1 of the present embodiment is preferably a so-called grindstone processed portion finished by either grinding or polishing using a rotary grindstone. That is, the processing of the first rolling portion of the outer ring 11 and the inner ring 12, which are the first rolling parts, is performed only by either grinding or polishing using a rotary grindstone. Therefore, the first rolling portion is not subjected to any of superfinishing, barrel polishing, and burnishing after the grinding or polishing. In other words, the surface of the first rolling portion of the deep groove ball bearing 1 is a ground portion that is only ground using a rotary grindstone and then is not subjected to superfinishing, barrel polishing, or burnishing. , Or a polished portion that is only polished using a rotary grindstone and is not subsequently subjected to superfinishing, barrel polishing, or burnishing.

In the present embodiment, in the rolling bearing as the deep groove ball bearing 1 composed of the rolling device having the above characteristics, the outer ring 11 and the inner ring 12 are composed of the first rolling component as described above. , The ball 13 is composed of a second rolling component.

In the rolling bearing, the rockwell hardness of each of the outer ring raceway surface 11A, the inner ring raceway surface 12A, and the ball raceway surface 13A as the raceway surfaces of the plurality of balls 13 is 60 HRC or more.

In the rolling bearing, it is preferable that the oil film parameter in lubrication between each of the outer ring 11 and the inner ring 12 and the ball 13 is 1.2 or less. That is, it is preferable that the rolling bearing is used under the condition that the value of the oil film parameter Λ in the region between the outer ring 11 and each of the plurality of balls 13 is 1.2 or less. Similarly, the rolling bearing is preferably used under the condition that the value of the oil film parameter Λ in the region between the inner ring 12 and each of the plurality of balls 13 is 1.2 or less.

Next, although there is a description that partially overlaps with the above, the action and effect of the present embodiment will be described.
The deep groove ball bearing (1) as the rolling device of the present embodiment includes a first rolling component (11, 12) and a second rolling component (13). The second rolling component (13) comes into contact with the first rolling component (11, 12). The Rockwell hardness of the surface (11A, 12A) of the first rolling portion, which is the rolling portion of the first rolling component (11, 12), is the rolling portion of the second rolling component (13). It is lower than the Rockwell hardness of the surface (13A) of the second rolling portion. The Rockwell hardness of the surface (11A, 12A) of the first rolling portion is 62 HRC or less. The surface (11A, 12A) of the first rolling portion has a residual displacement amount after unloading when the hardness of the surface layer of the first rolling portion is measured by the nanoindentation method, and the maximum pushing load is 100 μN. Sometimes it is above 548 nm. The surface (11A, 12A) of the first rolling portion has a residual displacement amount after unloading when the hardness of the surface layer of the first rolling portion is measured by the nanoindentation method, and the maximum pushing load is 100 μN. It is more preferable that the thickness is 602 nm or more.

By combining the first rolling component and the second rolling component in this way, a large number of minute protrusions existing on the surface of the first rolling portion come into contact with the surface of the second rolling portion. Then, the minute protrusions become familiar. After the familiarization, it is promoted that the shape of the surface of the first rolling portion, particularly the radius of curvature (average value) β of the tip of the protrusion is increased. Further, this reduces the variation in the height direction positions of the vertices of the large number of protrusions, that is, the standard deviation σ ^* .

Generally, in the contact between two surfaces, the larger the radius of curvature β of the tip of the protrusion formed on the surface, the more the variation in the height direction position of the apex of the plurality of protrusions formed on the surface. As the standard deviation σ ^* is smaller, the contact state of the two surfaces at the contact portion between the plurality of protrusions on one surface and the other surface is improved. That is, the ratio of the number of protrusions that are in elastic contact with the other surface among the plurality of protrusions on one of the two surfaces increases. Such improvement of the contact state brings about suppression of fatigue in the surface layer of the rolling portion of the rolling component and reduction of the amount of wear in the surface layer of the rolling portion. As a result, damage to the surface of the first rolling portion and the surface of the second rolling portion can be suppressed. As a result, it is possible to suppress a decrease in the life of the rolling device due to surface damage of the rolling component.

According to the deep groove ball bearing (1) as the rolling device of the present embodiment, the arithmetic mean surface roughness of the surface (11A, 12A) of the first rolling portion and the surface (13A) of the second rolling portion is It is preferably 0.20 μm or less. In a general rolling bearing, the arithmetic mean roughness of the surface of the rolling portion is rarely larger than 0.50 μm. When the arithmetic mean roughness of the surface of the rolling portion is larger than 0.20 μm, for example, even if a plurality of protrusions formed on the surface of the first rolling portion are familiar, the degree of familiarization is high. Not enough. Therefore, the reliability of preventing surface damage at the first rolling portion or the second rolling portion is lowered. On the other hand, if the arithmetic mean surface roughness of the surface of the first rolling portion and the surface of the second rolling portion is 0.20 μm or less, the second rolling is caused by the familiarity of the protrusion of the first rolling portion. The surface damage of the part can be suppressed, and the risk of shortening the life of the entire rolling device can be reduced.

According to the deep groove ball bearing 1 as the rolling device of the present embodiment, the surface (11A, 12A) of the first rolling portion is finished by either grinding or polishing using a rotary grindstone. It is a grindstone processing part. In other words, the surface of the first rolling portion is only ground with a rotary grindstone and then not super-finished, barrel-polished, or burnished, or polished with a rotary grindstone. It is one of the polished parts that is only processed and then not subjected to super-finishing, barrel polishing, or burnishing. That is, it is possible to suppress the complexity of the processing process due to special processing such as super-finishing processing, barrel polishing processing, and burnishing processing. Further, by omitting these special processes, the processing cost can be reduced.

The deep groove ball bearing 1 as a rolling bearing composed of the rolling device of the present embodiment has an outer ring (11) having an outer ring raceway surface (11A) on the inner peripheral surface and an inner ring raceway surface (12A) on the outer peripheral surface. The inner ring (12) is provided with a ball (13) as a plurality of rolling elements that roll between the outer ring raceway surface (11A) and the inner ring raceway surface (12A). The outer ring (11) and the inner ring (12) are composed of a first rolling component, and the ball (13) is composed of a second rolling component. The rolling bearing 1 having the above-mentioned hardness and other conditions is used under conditions where the oil film forming property is not good because the lubrication state between each of the outer ring 11 and the inner ring 12 and the ball 13 is not good, but the outer ring raceway surface. It is possible to suppress surface damage of the ball 13 due to contact between the minute protrusions of 11A and the inner ring raceway surface 12A and the protrusions of the ball 13. As a result, a long life of the deep groove ball bearing 1 as a rolling bearing can be realized.

In the deep groove ball bearing (1) as the rolling bearing of the present embodiment, the Rockwell hardness of each of the outer ring raceway surface (11A), the inner ring raceway surface (12A), and the ball bearing surface (13A) is 60 HRC or more. Is preferable. By doing so, it is possible to suppress a decrease in the rolling fatigue life of the rolling bearing due to an excessive decrease in surface hardness of each raceway surface such as the outer ring raceway surface 11A. Here, in particular, it is possible to suppress a decrease in the life of the deep groove ball bearing 1 due to damage in a depth range of about 100 μm or more and 300 μm or less from the surface of each of the raceway surfaces, that is, occurrence of internal origin type peeling.

In the deep groove ball bearing (1) as the rolling bearing of the present embodiment, the oil film parameter Λ in lubrication between each of the outer ring (11) and the inner ring (12) and the ball (13) is 1.2 or less. Is preferable. The phenomenon of familiarization of the protrusions is particularly likely to proceed under the condition that the oil film parameter Λ of the first rolling component or the second rolling component is not good in oil film forming property and is 1.2 or less. Further, under the condition that the oil film parameter Λ is 1.2 or less, the protrusion on the surface of the first rolling portion comes into contact with the surface of the second rolling portion, so that the life is shortened due to the surface damage of the second rolling portion. It is easy to happen. Therefore, in the present embodiment, under the condition that the hydraulic parameter Λ is 1.2 or less, which would normally cause a decrease in the life of the second rolling portion, the outer ring raceway surface 11A and the inner ring raceway surface 12A have minute protrusions. The effect of suppressing damage to the surface of the first rolling portion or the second rolling portion due to contact with the minute protrusions of the ball 13 is exhibited. Therefore, a long life of the rolling bearing can be realized due to the familiarity of the protrusions.

(Embodiment 2)
The deep groove ball bearing as the rolling bearing of the present embodiment is basically the deep groove ball bearing 1 of FIGS. 1 and 2. The deep groove ball bearing 1 is basically composed of the same rolling elements as those described in the first embodiment. Therefore, the description of the same features as in the first embodiment in the present embodiment will not be repeated. However, in the present embodiment, in the rolling bearing as the deep groove ball bearing 1 configured by the rolling device, contrary to the first embodiment, the outer ring 11 and the inner ring 12 are composed of the second rolling component and are balls. Reference numeral 13 is a first rolling component.

First, in the rolling apparatus according to the present embodiment, consider a case where the surface roughness of the two rolling parts of the first rolling component and the second rolling component is the same. Here, the surface roughness means, for example, the arithmetic mean roughness or the average value of the radius of curvature of the tip of a minute protrusion on the surface of the rolling portion. In this case, it is preferable to use the rolling component in which surface damage is preferentially generated in the rolling portion as the second rolling component. That is, when surface damage occurs preferentially on the outer ring raceway surface 11A or the inner ring raceway surface 12A, it is preferable to use the outer ring 11 and the inner ring 12 as the second rolling component as in the present embodiment. On the contrary, when the surface damage is preferentially generated on the ball raceway surface 13A, it is preferable to use the ball 13 as the second rolling component as in the first embodiment. In this way, the surface damage of the rolling portion of the second rolling component due to the protrusion of the rolling portion of the first rolling component due to the familiarity of the protrusion of the rolling portion of the first rolling component. Can be suppressed. This is because the contact state between the protrusion of the rolling portion of the first rolling component and the rolling portion of the second rolling component is improved by familiarization. As a result, the risk of shortening the life of the entire rolling device can be reduced.

Next, in the rolling apparatus according to the present embodiment, there is a case where there is a significant difference in the surface roughness of the rolling portion of the two rolling parts of the first rolling component and the second rolling component. Think. Here, the surface roughness means, for example, the arithmetic mean roughness or the average value of the radius of curvature of the tip of a minute protrusion on the surface of the rolling portion. In this case, it is preferable that the rolling component having the larger surface roughness of the rolling portion is used as the first rolling component. In this way, the radius of curvature of the tip of the protrusion becomes large due to the familiarity of the protrusion with the surface roughness of the rolling portion of the first rolling component. As a result, it is possible to suppress surface damage to the rolling portion of the second rolling component due to the protrusion of the rolling portion of the first rolling component. This is because the contact state between the protrusion of the rolling portion of the first rolling component and the rolling portion of the second rolling component is improved by familiarization. Therefore, the risk of shortening the life of the entire rolling device can be reduced.

Hereinafter, examples of the present invention will be described.
FIG. 3 is a schematic view showing the configuration of the two-cylindrical tester in the embodiment. Using the two-cylindrical tester 4 shown in FIG. 3, a rolling fatigue test was performed using the 13 types of test pieces described below. With reference to FIG. 3, the two-cylindrical tester 4 mainly includes a drive-side rotary shaft D1, a driven-side rotary shaft F1, a refueling felt pad 5, and a motor M.

The drive-side rotation shaft D1 is a member extending in the left-right direction in FIG. A tip portion is provided on the right end side of FIG. 3 of the drive side rotation shaft D1. The tip portion has a shape in which the cross-sectional area intersecting the left-right direction of FIG. 3, which is the extending direction, gradually decreases from the left side to the right side of the figure. The motor M is connected to the end portion of the drive-side rotation shaft D1 opposite to the tip end portion, that is, the end portion on the left end side of FIG. The drive-side rotation shaft D1 is configured to be rotatable around the central shaft C1 extending in the left-right direction in FIG. 3 by the motor M.

A drive-side test piece D2 as a test piece was fixed to the tip of the drive-side rotary shaft D1 in FIG. The drive-side test piece D2 is a member corresponding to the first rolling component in each of the above embodiments. The drive-side test piece D2 can be rotated around the central axis C1 in the same manner as long as the drive-side rotation axis D1 rotates around the central axis C1.

On the other hand, the driven side rotation shaft F1 is also a member extending in the left-right direction in FIG. However, the arrangement of the driven side rotating shaft F1 is opposite to that of the driving side rotating shaft D1 in the left-right direction. That is, a tip portion is provided on the left end side of FIG. 3 of the driven side rotating shaft F1. The tip portion has a shape in which the cross-sectional area intersecting the left-right direction of FIG. 3, which is the extending direction, gradually decreases from the right side to the left side of the figure. Further, the driven side rotation shaft F1 has an end portion on the opposite side to the tip end portion, that is, the right end portion in FIG.

A driven side test piece F2 as a test piece was fixed to the tip of the driven side rotating shaft F1 in FIG. The driven side test piece F2 is a member corresponding to the second rolling component in each of the above embodiments. The driven side test piece F2 can rotate around the central axis C2 in the same manner as long as the driven side rotating shaft F1 rotates around the central axis C2. That is, the driven side rotation axis F1 is configured to be rotatable around the central axis C2 extending in the left-right direction in FIG.

Here, the tip of the drive-side rotary shaft D1 faces the right side of FIG. 3, and the tip of the driven-side rotary shaft F1 faces the left side of FIG. However, the central axis C1 of the drive side rotation axis D1 and the central axis C2 of the driven side rotation axis F1 do not coincide with the axial direction which is the left-right direction in FIG. That is, there is an interval shown in the vertical direction of FIG. 3 between the central axis C1 and the central axis C2. This interval is the outer diameter surface farthest from the central axis C1 of the driving side test piece D2 and the outer diameter farthest from the central axis C2 of the driven side test piece F2 when the driving side rotating shaft D1 is not rotating. The interval of contact with the surface was set.

Therefore, if the drive-side rotary shaft D1 and the drive-side test piece D2 fixed to the drive-side rotary shaft D1 rotate around the central axis C1, the driven-side test piece F2 that comes into contact with the drive-side test piece D2 and the driven side to which this is fixed are fixed. The rotation axis F1 was installed so as to rotate around the central axis C2. In order to make this possible, the driving side test piece D2 and the driven side test piece F2 both have a circular cross-sectional shape when viewed in a plan view from the direction intersecting the central axes C1 and C2, and are entirely cylindrical. And said. The driving side test piece D2 and the driven side test piece F2 arranged so as to be in contact with each other are configured to be in contact with the refueling felt pad 5 arranged on the back side in the paper surface direction, that is, directly below in the paper surface direction of FIG.

The dimensions of the prepared driving side test piece D2 and the driven side test piece F2, and the surface roughness of the outer diameter surface in the initial state before the test of each test piece in the axial direction (horizontal direction in FIG. 3) are shown. Shown in 1. Here, the surface roughness means the arithmetic mean roughness Ra.

As shown in Table 1, the drive-side test piece D2 has an outer diameter (diameter) of 40 mm in a plan view, a thickness (dimension extending in the axial direction) of 12 mm, and an axial minor curvature of the drive-side test piece D2. It has a cylindrical shape with a radius of 60 mm. The driven side test piece F2 has an outer diameter (diameter) of 40 mm in a plan view, a thickness (dimension extending in the axial direction) of 12 mm, and no axial secondary radius of curvature of the drive side test piece D2 (at 0 mm). There is) Cylindrical shape. Although not shown in Table 1, both the driving side test piece D2 and the driven side test piece F2 have an inner diameter (diameter) of 20 mm in a plan view.

As shown in Table 1, the drive side test piece D2 is finished with an axial average roughness of the outer diameter surface of 0.20 μm, and the driven side test piece F2 has an axial average roughness of the outer diameter surface. It was finished to 0.02 μm. Specifically, the outer diameter surface of the drive-side test piece D2 was finished by grinding using a rotary grindstone so that a work grain was formed in the circumferential direction. The outer diameter surface of the driven side test piece F2 was finished by grinding using a rotary grindstone so that a work grain was formed in the circumferential direction, and then further superfinishing was performed.

Table 2 shows the conditions for performing the rolling fatigue test performed using the driving side test piece D2 and the driven side test piece F2.

As shown in Table 2, additive-free poly-α-olefin oil (corresponding to VG6) was used as the lubricating oil in the bicylindrical tester 4. This lubricating oil was impregnated in the felt pad 5 for lubrication, and was applied and supplied to the outer diameter surfaces of the driving side test piece D2 and the driven side test piece F2 from there. As a test condition, the value of the load W (see FIG. 3) applied to the driven side test piece F2 was set to 230 kgf. Here, the load W refers to the driven side test piece F2 in the direction of the load W shown by the arrow in FIG. 3, that is, in the direction in which the driven side rotating shaft F1 approaches the driving side rotating shaft D1 when the driving side rotating shaft D1 rotates. It means the force applied to it. As the drive-side rotary shaft D1 is rotated around the central shaft C1 by the motor M, the driven-side rotary shaft F1 is rotated around the central shaft C2 in the opposite directions to the drive-side rotary shaft D1. The reason for the rotation in this way is that the outer diameter surface of the driving side test piece D2 and the outer diameter surface of the driven side test piece F2 are in contact with each other. The above driving conditions and the conditions of the dimensions, shape, and surface roughness of the driving side test piece D2 and the driven side test piece F2 shown in Table 1 were set. Generally, a minute convex portion existing on the outer diameter surface (surface of the rolling portion) of the driving side test piece D2 comes into contact with the outer diameter surface (surface of the rolling portion) of the driven side test piece F2. Rolling fatigue is likely to occur on the surface of the rolling portion of the driven side test piece F2.

The test was performed under intermittent operation conditions, and the rotation speed of the drive-side rotation shaft D1 was set to 500 min ^-1 from the start of the test, that is, the rotation of the drive-side rotation shaft D1 to the lapse of 2 minutes. Two minutes after the start of rotation of the drive-side rotation shaft D1, the rotation was interrupted once, and the drive-side rotation shaft D1 was stopped. This time point is the time when the number of loads applied to the driving side test piece D2 and the driven side test piece F2 reaches 1000 times. This is because every time the drive-side rotation shaft D1 makes one rotation, a load is applied to the drive-side test piece D2 and the driven-side test piece F2 once. After that, the rotation of the drive-side rotation shaft D1 was restarted, and the drive-side rotation shaft D1 was rotated for 2 minutes at a rotation speed of 2000 min ^-1 . As a result, the test was finally completed when the total number of loads applied to the driving side test piece D2 and the driven side test piece F2 reached 5000 times.

It should be noted that the reason why the drive-side rotation shaft D1 was first rotated at 500 min ^-1 for 2 minutes is that the minute protrusions existing in the rolling portion of the drive-side test piece D2 during the rotation for 2 minutes are familiar. Depends on the purpose of proceeding. And rotated for 2 min at this 500 min ^-1, during the rotation for 2 minutes in the subsequent 2000 min ^-1, rolling portion i.e. the outer diameter surface of the drive-side specimen D2 and the driven-side test piece F2 is cause rolling contact fatigue .. This is because the outer diameter surfaces of the driving side test piece D2 and the driven side test piece F2 repeatedly receive a load due to contact at high speed during rotation. In this test, after increasing the rotation speed of the drive side rotation shaft D1 to 2000 min ^-1 and rotating it for an additional 2 minutes, the surface roughness on the surface of the rolling portion of the drive side test piece D2 and the driven side test piece F2 The degree of fatigue generated on the surface of the rolling part was evaluated. As a result, it is possible to evaluate the influence of the familiarity of the minute convex portion on the surface of the rolling portion of the driving side test piece D2 under each evaluation product, that is, the influence on the fatigue progress of the surface of the rolling portion of the driven side test piece F2. ..

In this embodiment, the two-cylindrical tester 4 described above and the above procedure are used to combine the conditions of the four types of drive-side test piece D2 and driven-side test piece F2 based on the characteristics of the present embodiment. Four types of rolling fatigue tests used, and nine types of rolling fatigue tests as comparative examples using a combination of standard products of nine types of driving side test piece D2 and driven side test piece F2 were performed. In the following, each of the four types of tests using the combination of the above four types of conditions based on the characteristics of the present embodiment is shown in Examples 1 to 4. Further, in the following, nine types of tests using a standard product, that is, a combination of the driving side test piece D2 and the driven side test piece F2, which are out of the standard of the present embodiment, are shown in Comparative Examples 1 to 9. Table 3 below shows the materials, end face hardness, and formation conditions of the test pieces of Comparative Examples 1 to 9 and Examples 1 to 4, respectively.

First, the drive side test piece D2 will be described. As shown in Table 3, in Comparative Examples 1 to 3, the material of the driving side test piece D2 was JIS standard SUJ2. All of these drive-side test pieces D2 were quenched under the same temperature and other conditions, and then tempered at the temperatures shown in Table 3. Specifically, tempering was performed at 180 ° C. in Comparative Example 1, 150 ° C. in Comparative Example 2, and 230 ° C. in Comparative Example 3. As a result, each of these drive-side test pieces D2 had the end face hardness shown in Table 3. Here, the end face means a surface other than the outer diameter surface which is the rolling portion of each drive side test piece D2. Further, the end face hardness means the Rockwell hardness (unit: HRC) of the end face other than the outer diameter surface which is the rolling portion of each drive side test piece D2. Specifically, it was 63.5 HRC in Comparative Example 1, 65.0 HRC in Comparative Example 2, and 60.9 HRC in Comparative Example 3. Comparative Example 1 is the most general-purpose material for rolling bearings, etc., among the non-standard standard products of the present embodiment. Therefore, the explanation of the results described below is verified based on the results of Comparative Example 1.

In Comparative Examples 4 to 7, the material of the drive-side test piece D2 was JIS standard SUJ3. Of the drive-side test pieces D2 of these comparative examples, the drive-side test pieces D2 of Comparative Examples 4 to 6 were quenched under the same temperature and other conditions. However, only the drive-side test piece D2 of Comparative Example 7 was quenched at a higher temperature than the drive-side test piece D2 of Comparative Examples 4 to 6. After that, tempering was performed at the temperatures shown in Table 3, respectively. Specifically, tempering was performed at 150 ° C. in Comparative Example 4, 180 ° C. in Comparative Example 5, 230 ° C. in Comparative Example 6, and 180 ° C. in Comparative Example 7. As a result, each of these drive-side test pieces D2 had the end face hardness shown in Table 3. Specifically, it was 64.5 HRC in Comparative Example 4, 62.4 HRC in Comparative Example 5, 61.3 HRC in Comparative Example 6, and 62.3 HRC in Comparative Example 7.

In Examples 1 and 2, the material of the drive-side test piece D2 was JIS standard SNCM815. All of these drive-side test pieces D2 were quenched under the same temperature and other conditions, followed by intermediate annealing and secondary quenching. After that, each of these drive-side test pieces D2 was tempered at the temperatures shown in Table 3. Specifically, tempering was performed at 150 ° C. in Example 1 and 180 ° C. in Example 2. As a result, each of these drive-side test pieces D2 had the end face hardness shown in Table 3. Specifically, it was 60.1 HRC in Example 1 and 58.8 HRC in Example 2.

In Comparative Example 8 and Example 3, the material of the drive-side test piece D2 was JIS standard SNCM420. All of these drive-side test pieces D2 were quenched under the same temperature and other conditions, and then tempered at the temperatures shown in Table 3. Specifically, tempering was performed at 150 ° C. in Comparative Example 8 and 180 ° C. in Example 3. As a result, each of these drive-side test pieces D2 had the end face hardness shown in Table 3. Specifically, it was 62.7 HRC in Comparative Example 8 and 60.8 HRC in Example 3.

In Comparative Example 9 and Example 4, the material of the drive-side test piece D2 was JIS standard SCM420. All of these drive-side test pieces D2 were quenched under the same temperature and other conditions, and then tempered at the temperatures shown in Table 3. Specifically, tempering was performed at 150 ° C. in Comparative Example 9 and 180 ° C. in Example 4. As a result, each of these drive-side test pieces D2 had the end face hardness shown in Table 3. Specifically, it was 63.5 HRC in Comparative Example 9 and 61.8 HRC in Example 4.

Next, the driven side test piece F2 will be described. As shown in Table 3, in all of Comparative Examples 1 to 9 and Examples 1 to 4, the material of the driven test piece F2 was JIS standard SUJ2. All of these driven test pieces F2 were quenched under general temperature and other conditions, and then tempered at 180 ° C. As a result, the end face hardness of all of these driven test pieces F2 was almost the same as 63.4 ± 0.2 HRC.

Each of the driving side test pieces D2 and each driven side test piece F2 of Comparative Examples 1 to 9 and Examples 1 to 4 had a Rockwell hardness locked on the end face of each test piece before the above-mentioned rolling fatigue test. Measured by a well hardness tester. In addition to this, for each of the driving side test pieces D2 of Comparative Examples 1 to 3 and 5 to 7 and Examples 2 to 4, the hardness of the surface layer of the end face of each test piece was measured by the nanoindentation method. It was. FIG. 4 is a graph schematically showing the relationship between the depth at which the microindentor is pushed into the measurement target during the nanoindentation method and the load applied when the minute indenter is pushed. The horizontal axis of FIG. 4 shows the depth at which the microindenter is pushed into the measurement target during the nanoindentation method. Therefore, the residual displacement amount hf after unloading, which will be described later, is represented by this horizontal axis. The vertical axis of FIG. 4 shows the load applied by the microindenter to the measurement target during the nanoindentation method.

With reference to FIG. 4, if the microindentor pushes the measurement target during the measurement using the nanoindentation method, it is pushed into the surface of the measurement target even after the measurement is completed (that is, even if the pushing load is not applied). The displacement generated when the load remains. This residual amount is shown as the residual displacement amount hf after unloading in FIG. Further, in this measurement, the maximum pushing load P _max to the surface layer by the minute indenter was 100 μN, particularly for the end faces of the driving side test pieces D2 of Comparative Examples 1 to 3 and Comparative Examples 5 to 7 and Examples 2 to 4. After the hardness of the surface layer was measured, the residual displacement amount hf after unloading was measured. Here, the end surface on which the residual displacement amount hf is measured for each drive-side test piece D2 is a surface different from the rolling portion (outer diameter surface) on which the rolling fatigue test is performed. That is, indentation remains in the region that is not affected by fatigue by the rolling fatigue test by the nanoindentation method. However, it is assumed that the hardness of the end face has the same Rockwell hardness as the surface of the outer diameter surface which is the rolling portion. Therefore, measuring the hardness of the end face gives the same result as measuring the hardness of the rolling portion (the surface of the first rolling portion and the surface of the second rolling portion).

The residual displacement amount hf (unit: nm) after unloading was measured at 20 different locations for each drive-side test piece D2 of Comparative Examples 1 to 3 and 5 to 7 and Examples 2 to 4. .. The average value of the residual displacement amount hf after unloading at 20 places of each test piece was recorded as the residual displacement amount hf after unloading of the test piece. The microindenter used for the measurement was a Berkovich indenter.

After the rolling fatigue tests of Comparative Examples 1 to 9 and Examples 1 to 4 were performed using the test pieces shown in Table 3, the drive-side test pieces D2 of Comparative Examples 1 to 9 and Examples 1 to 4 were used. The average value β of the radius of curvature of the tip of the protrusion formed on the surface of the rolling portion was measured. Further, the standard deviation σ ^* of the height of the apex of the protrusion formed on the surface of the rolling portion of each drive side test piece D2 was measured. From these, the degree of familiarity with the protrusions was evaluated. Here, β and σ ^* were calculated using surface roughness analysis software after measuring the three-dimensional surface shape of the rolling portion of each drive-side test piece D2 with a laser microscope. Note that these β and σ ^* values are parameters of three-dimensional, that is, surface roughness, not two-dimensional, that is, line roughness.

In addition to the measurement of β and σ ^{* on} the surface of the rolling portion of the drive-side test piece D2, each drive-side test piece D2 of Comparative Examples 1 to 3 and 5 to 7 and Examples 2 to 4 is The standard deviation σ ^* of the surface of the rolling part of the driving side test piece D2 is measured not only after the intermittent operation test (rolling fatigue test) in which the load is applied 5000 times, but also before the rolling fatigue test. Was done. Then, the amount of change in the standard deviation σ ^* of each drive-side test piece D2 before and after the rolling fatigue test was calculated.

Further, in addition to the above-mentioned measurement of β and σ ^* , measurement of surface layer hardness, and measurement of residual displacement amount hf after unloading, each drive-side test piece D2 of Comparative Examples 1 to 9 and Examples 1 to 4 and each of them. The residual stress of the rolling portion of the driven test piece F2 after the rolling fatigue test was measured. Here, the residual stress was measured by X-ray diffraction analysis. Further, during the X-ray diffraction analysis, X-rays are incident on the rolling portion from three different directions, and based on the diffraction information obtained for the incident of X-rays from each direction, the driven side test piece F2 The residual stress of the surface layer of the rolling part (the region within 5 μm from the surface) was calculated in the form of the equivalent stress of von Mises. In general, normal stress and shear stress in various directions are simultaneously generated on the surface layer of the rolling portion during rolling. The equivalent stress of von Mises is the conversion of the multiaxial stress acting simultaneously in this way into a single stress. The equivalent stress of von Mises is considered to be effective in examining the behavior of plastic deformation and fatigue of materials on which multiaxial stress acts. Further, the formation of residual stress in the rolling portion means that plastic deformation has occurred in the rolling portion. That is, the magnitude of the formed residual stress represents the degree of plastic deformation, and it is considered that the larger the residual stress, the larger the degree of plastic deformation.

<Test result>
FIG. 5 shows the relationship between the Rockwell hardness of the end surface of the driving side test piece D2 other than the rolling portion before the rolling fatigue test and the β on the surface of the rolling portion of the driving side test piece D2 after the rolling fatigue test. It is a graph which shows. The horizontal axis of FIG. 5 indicates the Rockwell hardness of the end face of the drive-side test piece D2 other than the rolling portion, which was measured before the rolling fatigue test (unit: HRC). The vertical axis of FIG. 5 shows the above β. The black triangle mark in FIG. 5 indicates the value in Comparative Example 1. The black circles in FIG. 5 indicate the values in each of Comparative Examples 2 to 9. The white circles in FIG. 5 indicate the values in each of Examples 1 to 4. With reference to FIG. 5, it can be seen that there is a linear correlation between the Rockwell hardness of the drive-side test piece measured before the rolling fatigue test and β. Further, from FIG. 5, it can be said that the lower the Rockwell hardness, the larger the β after familiarization. That is, the familiarity increases the radius of curvature β at the tip of the protrusion on the surface of the rolling portion. Then, at least in the tests of Examples 1 to 4 in which the Rockwell hardness is 62 HRC or less, the β value after the test shows a value equal to or higher than that of Comparative Example 1 showing a reference value. When the radius of curvature β becomes large, as described above, fatigue in the surface layer of the rolling portion of the rolling part is suppressed, and the amount of wear in the surface layer of the rolling portion is reduced. As a result, damage to the surface of the first rolling portion and the surface of the second rolling portion can be suppressed. As a result, it is possible to suppress a decrease in the life of the rolling device due to surface damage of the rolling component. From the above, it can be seen that the Rockwell hardness of the surface of the first rolling component corresponding to the drive-side test piece D2 is preferably 62 HRC or less.

FIG. 6 shows the amount of residual displacement after unloading when the hardness of the surface layer of the end face other than the rolling portion of the driving side test piece D2 before the rolling fatigue test was measured by the nanoindentation method, and the driving side test piece. It is a graph which shows the relationship with the amount of change of the standard deviation σ ^* of the surface of the rolling part of D2 before and after a rolling fatigue test. The horizontal axis of FIG. 6 indicates the residual displacement amount hf after unloading when the hardness of the surface layer of the rolling portion of the driving side test piece D2 before the rolling fatigue test is measured by the nanoindentation method as “residual strain”. It is shown as (unit: nm). The vertical axis of FIG. 6 shows the amount of change in the standard deviation σ ^* of the surface of the rolling portion of the driving side test piece D2 before and after the rolling fatigue test (unit: μm). The black triangle mark in FIG. 6 indicates the value in Comparative Example 1. The black circles in FIG. 6 indicate the values in Comparative Examples 2, 3, 5, 6, and 7. The white circles in FIG. 6 indicate the values in Examples 2, 3 and 4. Of the black circles in FIG. 6, the black circles according to Comparative Example 3 and Comparative Example 6 substantially overlap at positions where the residual strain is about 525 nm and the amount of change in σ ^* is about 0.022 μm. ..

From the above description, it is preferable that the value of the standard deviation σ ^* is small from the viewpoint of suppressing damage to the surface of the first rolling portion and the surface of the second rolling portion and suppressing a decrease in the life thereof. However, this is a story after the minute protrusions have become familiar with use. It is sufficient that the standard deviation σ ^* is smaller after the familiarization (that is, after the rolling fatigue test) than in the initial state before the familiarization (that is, before the rolling fatigue test). In other words, even if σ ^* is large in the initial state, if σ ^* is significantly reduced due to subsequent familiarization, the effect of suppressing the decrease in life can be enhanced. In this case, the amount of change (decrease) in σ ^* is large, which is preferable data. From this point of view, it is preferable that the amount of change in σ ^* before and after the test indicated by the vertical axis of the graph is large in order to achieve the effects of the present invention.

Based on the above, with reference to FIG. 6, there is a tendency that the larger the residual displacement amount hf after unloading, the larger the amount of change in σ ^* due to familiarity, which is a preferable result. The two broken lines in the figure indicate the upper and lower limits of the prediction interval when it is assumed that there is a linear correlation between hf and the amount of change in σ ^* . The two chain lines in the figure show the upper and lower limits of the confidence interval when it is assumed that there is a linear correlation between hf and the amount of change in σ ^* . Both the prediction interval and the confidence interval above plot values with a risk factor of 5%. From the viewpoint that the amount of change in σ ^* due to familiarity is equal to or greater than that of Comparative Example 1 as the reference value, it can be seen that hf is required to be 548 nm or more from the lower limit of the confidence interval (see point A in FIG. 6). .. Further, from the viewpoint that the amount of change in σ ^* due to familiarity is equal to or higher than that of Comparative Example 1 which is the reference value, it can be seen that hf of 602 nm or more is more preferable than the lower limit of the prediction interval (see point B in FIG. 6). ..

FIG. 7 shows the values of σ ^* / β on the surface of the rolling portion of the driving side test piece D2 after the rolling fatigue test and the residual stress on the surface of the rolling portion of the driven side test piece F2 after the rolling fatigue test. It is a graph which shows the relationship with. The black circles in FIG. 7 indicate the values in Comparative Example 1, and the black X marks are any of Comparative Examples 2 to 9 and Examples 1 to 4, and the Rockwell hardness of the end face of the driving side test piece D2. Is the data of the test piece higher than the Rockwell hardness of the end face of the driven side test piece F2. The white diamond in FIG. 7 is different from any of the black circles and crosses in Comparative Examples 2 to 9 and Examples 1 to 4, and locks the end face of the drive-side test piece D2. It is the data of the test piece whose well hardness is equal to or less than the Rockwell hardness of the end face of the driven side test piece F2.

With reference to FIG. 7, the white diamond-shaped data has a relatively low residual stress on the surface of the rolling portion of the driven test piece F2, which is relatively lower in the graph. Therefore, in order to suppress the generation of residual stress (that is, plastic deformation) on the driven side test piece F2, the hardness (of the end face) of the driven side test piece D2 before the rolling fatigue test is changed to the driven before the rolling fatigue test. It is effective to make it lower than the hardness (of the end face) of the side test piece F2. Further, in the graph of FIG. 7, the smaller the σ ^* / β, the smaller the residual stress of the driven test piece F2 tends to be. This result shows that either the σ ^* after the rolling fatigue test becomes smaller due to familiarity, or the rate of increase in β after the rolling fatigue test increases, so that the rolling part of the driven test piece F2 It is shown that the plastic deformation of the surface can be suppressed.

The features described in each of the above-described embodiments (each example included in the above) may be applied so as to be appropriately combined within a technically consistent range.

It should be considered that the embodiments disclosed this time are exemplary in all respects and not restrictive. The scope of the present invention is shown by the scope of claims rather than the above description, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

1 Deep groove ball bearing, 4 2 Cylindrical tester, 5 Refueling felt pad, 11 Outer ring, 11A Outer ring raceway surface, 12 Inner ring, 12A Inner ring raceway surface, 13 balls, 13A ball raceway surface, 14 Cage, D1 Drive side rotating shaft , D2 drive side test piece, F1 driven side rotating shaft, F2 driven side test piece, M motor, W load.

Claims (8)

The first rolling component and
A second rolling component that comes into contact with the first rolling component is provided.
The Rockwell hardness of the surface of the first rolling portion, which is the rolling portion of the first rolling component, is the Rockwell hardness of the surface of the second rolling portion, which is the rolling portion of the second rolling component. Lower than
The Rockwell hardness of the surface of the first rolling portion is 62 HRC or less.
The surface of the first rolling portion has a residual displacement amount after unloading when the hardness of the surface layer of the first rolling portion is measured by the nanoindentation method, which is 548 nm when the maximum pushing load is 100 μN. That's all, the rolling device. The surface of the first rolling portion has a residual displacement amount after unloading when the hardness of the surface layer of the first rolling portion is measured by the nanoindentation method, which is 602 nm when the maximum pushing load is 100 μN. The rolling device according to claim 1, which is the above. The rolling apparatus according to claim 1 or 2, wherein the arithmetic average surface roughness of the surface of the first rolling portion and the surface of the second rolling portion is 0.20 μm or less. The rolling apparatus according to any one of claims 1 to 3, wherein the surface of the first rolling portion is a grindstone processing portion finished only by either grinding or polishing using a rotary grindstone. .. A rolling bearing composed of the rolling element according to any one of claims 1 to 4.
An outer ring having an outer ring raceway surface on the inner peripheral surface,
An inner ring having an inner ring raceway surface on the outer peripheral surface,
A plurality of rolling elements that roll between the outer ring raceway surface and the inner ring raceway surface are provided.
A rolling bearing in which the outer ring and the inner ring are made of the first rolling component, and the rolling element is made of the second rolling component. A rolling bearing composed of the rolling element according to any one of claims 1 to 4.
An outer ring having an outer ring raceway surface on the inner peripheral surface,
An inner ring having an inner ring raceway surface on the outer peripheral surface,
A plurality of rolling elements that roll between the outer ring raceway surface and the inner ring raceway surface are provided.
A rolling bearing in which the outer ring and the inner ring are made of the second rolling component, and the rolling element is made of the first rolling component. The rolling bearing according to claim 5 or 6, wherein the rockwell hardness of each of the outer ring raceway surface, the inner ring raceway surface, and the raceway surfaces of the plurality of rolling elements is 60 HRC or more. The rolling bearing according to any one of claims 5 to 7, wherein the oil film parameter in lubrication between each of the outer ring and the inner ring and the rolling element is 1.2 or less.

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