JP2002115031A - Rolling bearing parts, driving device and roll supporting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide rolling bearing parts in which the dimensional change and the reduction of hardness at a high temperature are prevented, the occurance of damage started from the surface caused by a low viscous lubricant or the like is prevented, and a long service life can be secured. SOLUTION: Any of rolling bearing parts 1, 2 and 3 is composed of steel at least containing, as alloy elements, by mass, 0.6 to 1.3% C, 0.3 to 3.0% Si, 0.1 to 3.0% Ni, 1.0 to 2.0% Mn and 0.3 to 5.0% Cr, and when tempering is performed at a tempering temperature of 260 to 350 deg.C, the content of retained austenite in the surface layer is >=10 vol.%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rolling bearing, a driving device, and a roll supporting device, and more specifically, a foreign material such as a transmission or a reduction gear is easily mixed therein, a use atmosphere temperature is high, and lubrication conditions are severe. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rolling bearing used for an application, and a driving device and a roll supporting device using the same.

[0002]

2. Description of the Related Art In recent years, in order to save energy and protect the global environment in automobiles and industrial machines, drive systems have been improved in efficiency and speed.
There is momentum to make it more compact. For this reason, the power transmission mechanism and the support mechanism constituting the same have come to be used under higher temperature, higher speed, and higher load conditions. For this reason, the operating environment of the rolling bearing, which is the main member of the support mechanism, is high temperature,
High speed, high load. Further, in order to reduce energy loss, the lubricant has a lower viscosity, and for a rolling bearing, metal contact occurs during use and surface damage is likely to occur. In addition, deterioration of the lubricating oil and mixing of abrasion powder occur due to long-term maintenance-free operation, and the use environment is more severe for bearings. Therefore, the bearing is required to have such a performance that the life is not reduced at a high temperature and that the life is not easily reduced even when foreign matters are mixed or diluted lubrication is performed.

[0003]

In the use environment as described above, a normal bearing steel bearing causes dimensional changes at high temperatures, and the function cannot be secured. In order to be usable at a high temperature, it is necessary to temper at a higher temperature, and in this case, the rolling life is shortened due to a decrease in hardness. Furthermore, surface damage such as peeling and smearing resulting from peeling from the indentation and thinning of the lubricating oil film due to foreign matter being caught tend to occur as the hardness becomes lower, and the performance of the bearing cannot be ensured.

Accordingly, an object of the present invention is to provide a rolling bearing component and a rolling bearing component capable of ensuring a long durable life under the above-mentioned high temperature conditions and under conditions where surface origin type damage is likely to occur due to foreign matter entrapment or insufficient lubricating oil film. And a roll supporting device using the same.

[0005]

A rolling bearing part according to the present invention is a part of a rolling bearing having a bearing ring and a rolling element, wherein C (carbon) is 0.6% by mass as an alloy element.
Not less than 1.3%, not more than 0.3% and not more than 3.0% of Si (silicon), and not less than 0.1% and not more than 3.0% of Ni (nickel).
%, Mn (manganese) at least 1.0% to 2.0%, and Cr (chromium) at least 0.3% to 5.0%, and the amount of retained austenite in the surface layer is 10 vol. % Or more.

Since the rolling bearing component of the present invention has the above composition, it is tempered at a temperature of 230 ° C. or more and 350 ° C. or less to reduce the amount of retained austenite in the surface layer to 10%.
%. Since the retained austenite is soft, it functions as a buffer for preventing stress concentration when foreign matter is caught. As a result, stress concentration under lubricating conditions with foreign matter can be suppressed, resulting in excellent rolling fatigue characteristics and surface damage resistance under severe conditions where foreign matter is mixed at high temperatures, and excellent durability and reliability. Rolling bearing parts having a high bearing ratio can be obtained.

The amount of retained austenite in the surface layer is 10% by volume.
The reason for this is that if the content is less than 10% by volume, the effect as a buffering agent when the above-described foreign matter is caught is not sufficient. The amount of retained austenite in the surface layer was 20% by volume.
When the temperature exceeds the limit, the problem of a decrease in accuracy due to decomposition of austenite at the time of use at a high temperature becomes remarkable, so that the content is preferably 20% by volume or less.

Hereinafter, the reasons for limiting the chemical components of the rolling bearing of the present invention will be described. (1) Content of C (0.6% or more and 1.3% or less) C is an essential element for securing strength as a rolling bearing, and for maintaining hardness after a predetermined heat treatment. 0.
Since the content needs to be 6% or more, the lower limit of the C content is set to 0.6%. If the C content exceeds 1.3%, large carbides are formed and the rolling fatigue life is reduced. Therefore, the upper limit of the C content is set to 1.3%.

(2) Si content (0.3% or more;
(0% or less) The content of Si of 0.3% or more and 3.0% or less was
i has the effect of suppressing softening when exposed to high temperatures and improving heat resistance. Since the effect cannot be obtained if it is less than 0.3%, the lower limit of the Si content is set to 0.3%. In addition, heat resistance improves with an increase in the amount of Si,
Even if it is contained in a large amount exceeding 3.0%, the effect is saturated and hot workability and machinability are remarkably reduced.
The upper limit of the Si content was set to 3.0%.

(3) Ni content (0.1% or more;
(0% or less) Ni forms a solid solution in steel to strengthen the matrix, suppresses the structural change in the rolling fatigue process, especially when the parts are used at a high temperature, and suppresses the Also suppresses a decrease in hardness. Therefore, Ni has an effect of improving rolling fatigue characteristics and surface damage resistance under a high temperature environment.
In order to obtain these effects, it is necessary to contain Ni in an amount of 0.1% or more. Therefore, the lower limit of the Ni content is set to 0.1%. However, when Ni is contained in excess of 3.0%,
A large amount of retained austenite is generated during the quenching process,
Since the predetermined hardness cannot be obtained and the cost of the steel material becomes high, the upper limit of the Ni content is set to 3.0%.

(4) Mn content (1.0% or more and 2.0% or more)
% Or less) Mn improves the hardenability of the steel material and forms a solid solution in the steel to strengthen the steel. In addition, Mn increases the amount of retained austenite together with Ni, stabilizes the austenite at a high temperature, and retains the austenite even after high-temperature tempering. It is advantageous. However, since Mn strengthens ferrite, if it is too much, it hinders turning properties and machinability. Therefore, the lower limit of the Mn content is set to 1.0% and the upper limit is set to 2.0%.

(5) Cr content (from 0.3% to 5.0)
% Or less) Cr forms carbides and strengthens the steel. The lower limit of the Cr content is set to 0.3% in order to obtain these effects. The upper limit of the Cr content is limited to 5.0% in order to prevent embrittlement due to generation of large carbides. Cr
Has also been found to improve rolling life characteristics.

By the action of these alloy components, even if a large temperature rise occurs locally due to slip or the like, the surface is prevented from being softened, the surface damage resistance is improved, the retained austenite is stabilized, and the rolling life is improved. However, the characteristics can be further improved by adding the following amounts of V (vanadium) and Mo (molybdenum).

In the above rolling bearing component, preferably, at least one of V of 0.05% or more and 1.0% or less and Mo of 0.05% or more and less than 0.25% by mass as an alloying element is added to the steel material. Is added.

Thus, the rolling contact fatigue characteristics and the surface damage resistance can be further improved. (6) V and Mo contents (0.05% to 1.0%, 0.05% to less than 0.25%) V is 0.05% to 1.0% and Mo is 0.05. More than 0.25% each alone or in combination,
For the following reasons. V combines with carbon to precipitate fine carbides, refine crystal grains to improve strength and toughness, and suppress softening at high temperatures. Therefore, like Ni, V has the effect of improving rolling fatigue characteristics and surface damage resistance under a high temperature environment. In order to obtain this effect, the lower limit of the V content is set to 0.05%. The upper limit is set to 1.0% because if a large amount of V exceeds 1.0%, machinability and hot workability are reduced.

Mo improves the hardenability of steel, prevents temper embrittlement, and also suppresses softening at high temperatures. Therefore, Mo also has an effect of improving rolling fatigue characteristics and surface damage resistance under a high temperature environment. In order to obtain this effect, the lower limit of the Mo content is set to 0.05%. M
When the o content is 0.25% or more, the machinability decreases and the cost of steel material also increases. Therefore, the upper limit is limited to less than 0.25%.

Due to the action of each of the alloy elements described above, even if a high-temperature tempering treatment is performed in advance to prevent a dimensional change during use in a high-temperature environment, the surface hardness is equal to or higher than Rockwell hardness HRC 58 and the surface layer portion. Can maintain 10% by volume or more of retained austenite. As a result, the rolling life (both the cleaning oil lubrication life and the foreign matter mixing life) and the life of surface damage such as peeling and smearing can be improved.

Further, after a carbonitrided layer is formed on the surface layer of these bearings, high-temperature tempering is performed to secure an amount of retained austenite of the carbonitrided layer of 10% by volume or more to obtain a bearing having a higher temperature specification. be able to.

That is, when the nitrogen content of the surface layer is increased by the carbonitriding treatment, the Ms point (martensite transformation start temperature) of the surface layer is lowered, and when this is quenched, untransformed austenite is increased in the surface layer. Remains. Retained austenite has high toughness and work hardening characteristics, and functions to suppress the generation and propagation of cracks. Further, in the surface layer having the lowered Ms point, since the martensitic transformation starts later than the inside, residual stress of compression is formed in the surface layer, and the fatigue strength of the surface layer is improved. In the region where nitrogen has infiltrated, the tempering resistance (hardness due to tempering and stability against changes in microstructure) is further improved. As a result, the tempering temperature can be increased as compared with the case without carbonitriding and can be used at a higher temperature. In addition to the specifications, rolling life, peeling strength and smearing resistance are further improved.

Further, by performing high-temperature tempering so that the amount of retained austenite in the carbonitrided layer is 10% by volume or more,
By imparting high toughness to the surface layer, generation and propagation of cracks can be suppressed, and a bearing having a durable life and higher temperature specifications can be obtained.

A driving device according to the present invention is characterized by using the above-mentioned rolling bearing component. As a result, the rolling life,
It is possible to obtain a driving device having an excellent surface damage generation life.

The roll supporting device for a paper machine according to the present invention is a roll supporting device for a paper machine in which a roll is rotatably supported on a housing by a double row roller bearing. , C is 0.6% or more.
3% or less, Si is 0.3% or more and 3.0% or less, Ni is 0.1% or more and 3.0% or less, and Mn is 1.0% or more and 2.0% or less.
% Or less, and a steel material containing at least 0.3% or more and 5.0% or less of Cr, and the residual austenite amount of the surface layer is 10% by volume or more.

According to the roll supporting device of the paper machine of the present invention, since the components of the double row roller bearing have the same composition and structure as described above, the tempering temperature is set to 230 ° C. or more and 350 ° C. or less to perform the surface tempering. Can be 10% by volume or more. As a result, the rolling life and the life of the occurrence of surface damage such as peeling and smearing can be improved. For this reason,
Even when water enters the bearing and the lubricating oil film is thinned by being used in an environment where water is used, good peeling resistance and smearing resistance can be obtained and a long life can be obtained.

In the above-mentioned roll supporting device for a paper machine, the roll is preferably a dryer roll.

As a result, a good rolling life and a life of occurrence of surface damage can be obtained even in a dryer roll into which water easily enters.

In the above-described roll supporting device for a paper machine, the double row roller bearing is preferably a self-aligning roller bearing.

This self-aligning roller bearing is often used at a relatively low speed and a large load, so that the oil film is likely to break, and slippage occurs inside and relative slippage occurs within a contact ellipse, causing wear and surface damage. This is suitable for using the bearing component of the present invention.

The roll supporting device of the rolling equipment according to the present invention is a roll supporting device of a rolling equipment in which a roll is rotatably supported on a housing by a double row roller bearing, wherein the parts of the double row roller bearing are expressed in mass% as an alloy element. , C is 0.6% or more and 1.3% or less, Si is 0.3% or more and 3.0% or less, Ni
Is 0.1% or more and 3.0% or less, and Mn is 1.0% or more.
It is made of a steel material containing at least 0% or less and 0.3% or more and 5.0% or less of Cr, and is characterized in that the amount of retained austenite in the surface layer is 10% by volume or more.

According to the roll supporting device of the rolling equipment of the present invention, since the components of the double row roller bearing have the same composition and structure as described above, the tempering temperature is set to 230 ° C. or more and 350 ° C. or less to perform the tempering. Can be 10% by volume or more. As a result, the rolling life and the life of the occurrence of surface damage such as peeling and smearing can be improved. For this reason,
Even if water enters the bearings and the lubricating oil film becomes thinner due to use in an environment that uses water, good peeling resistance and smearing resistance can be obtained, and a long life can be achieved. .

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view schematically showing a configuration of a rolling bearing according to an embodiment of the present invention. With reference to FIG. 1, the rolling bearing 5 mainly has an inner ring 1, an outer ring 2, and a rolling element 3. The rolling element 3 is rotatably supported between the inner ring 1 and the outer ring 2.

At least one part of the rolling bearing 5 of the inner ring 1, the outer ring 2 and the rolling element 3 has a C content of 0.6% to 1.3% and a Si content of 0.3% by mass as an alloying element. % Or more and 3.0% or less, and Ni is 0.1% or more and 3.0% or less.
% Or less, Mn is 1.0% or more and 2.0% or less, and Cr is 0.1% or less.
It is made of a steel material containing at least 3% or more and 5.0% or less, and has 10% by volume or more of retained austenite in the surface layer when tempered at a tempering temperature of 230 ° C or more and 350 ° C or less.

At least one of the inner ring 1, the outer ring 2 and the rolling elements 3 is added to steel by mass% as an alloying element.
And V of 0.05% or more and 1.0% or less and 0.05%
It is preferable that at least one of Mo of at least 0.25% is added.

When the HRC is less than 58, in applications where a large load is applied, the life is shortened and the accuracy is deteriorated due to composition deformation. However, at least one of the inner ring 1, the outer ring 2 and the rolling elements 3 in the present embodiment has a surface hardness of Rockwell hardness HRC 58 or more due to the above-described composition and treatment. It is unlikely to cause accuracy deterioration.

The rolling bearing 5 of the present embodiment is, for example, a manual transmission 1 shown in FIG.
It may be used for a device driven by a gear like 0 (hereinafter, referred to as a driving device).

Referring to FIG. 2, the rolling bearing 5 of the present embodiment is used to support an input shaft 11, an output shaft 12, a pilot shaft 13 and a counter shaft 14.

The rolling bearing 5 may be any one of a cylindrical roller bearing, a needle roller bearing and a tapered roller bearing. The driving device is not limited to the above-described transmission, and may be a speed reducer or the like. The rolling device according to the present embodiment may be a device that is likely to be mixed with foreign substances and has a high use atmosphere temperature and is used for severe lubrication conditions. It is suitable for adopting a bearing.

Further, the rolling bearing of the present embodiment can be applied to a double row roller bearing in a roll supporting device of a paper machine, a double row roller bearing in a roll supporting device of a rolling facility, and the like. Hereinafter, a case where the present invention is applied to those double row roller bearings will be described.

FIG. 3 is a diagram illustrating a structural model of a four-stage hot rolling mill when the rolling bearing according to one embodiment of the present invention is applied to a double row roller bearing. Referring to FIG.
This four-stage hot rolling mill forms, for example, a finishing strand of a hot strip mill (a plurality of hot strand mills are installed along a hot rolling line), and performs rolling of a work W by a pair of works having a relatively small diameter. Performed by roll 21,
A backup roll 22 having a relatively large diameter above and below it.
Is provided to prevent the work roll 21 from bending due to the rolling load Fw. Backup roll 2
2 has a pressing force Fr by a pressing device 23 such as a hydraulic device.
Is given. A pressing device 24 such as a hydraulic device is interposed between the upper and lower work rolls 21, and a pressing force is applied by the pressing device 24. By giving bending deformation to the work roll 21 by this pressing force, the thickness control of the work roll 21 and the work W in the width direction is performed. The shaft ends 21a, 22a of the rolls 21, 22 are rotatably supported by housings 27, 28 by double row roller bearings 25, 26, respectively, and the housings 27, 28 are supported by a roll stand S, respectively.

In this embodiment, a four-row tapered roller bearing is used as the double-row roller bearing 25 for supporting the shaft end 21a of the work roll 21, and a double-row roller bearing 26 for supporting the shaft end 22a of the backup roll 22. A four-row cylindrical roller bearing is used. In addition, backup roll 2
In order to support a relatively small axial load acting on the second roller 2, a two-row tapered roller bearing 29 having a relatively large conical angle is disposed beside the four-row cylindrical roller bearing 26 at one shaft end 22 a.

Parts such as the rollers of the double-row roller bearings 25 and 26 and the double-row tapered roller bearing 29 are expressed by mass% as an alloying element, with C being 0.6% or more and 1.3% or less and Si being 0.1% or less. 3
% To 3.0%, Ni is 0.1% to 3.0%, Mn is 1.0% to 2.0%, and Cr is 0.3%.
At least 5.0% or less of steel material containing at least,
By performing the tempering at a tempering temperature of 230 ° C. or more and 350 ° C. or less, the surface layer has 10% or more of retained austenite.

FIGS. 4 and 5 are a cross-sectional view showing a configuration of a dryer roll of a paper machine when a rolling bearing according to an embodiment of the present invention is applied to a double row roller bearing, and an enlarged view of a bearing portion. It is sectional drawing.

Referring to FIG. 4, the dryer roll comprises a cylindrical roll body 31 and a pair of roll neck parts 33 and 34 having end plates 32 for sealing both ends of the roll body 31. The neck portions 33 and 34 are rotatably supported by double-row spherical roller bearings 35. At the center of the roll body 31, a steam introduction pipe 36 for internally heating the dryer roll is provided through one roll neck 33. A large number of holes 37 are provided in the steam introduction pipe. Water condensed from the holes 37 and heated to heat the roll body 31 is pumped up by a pumping wheel 38 and passed through the roll neck 33. The drainage pipe 39 is discharged to the outside.

Referring to FIG. 5, self-aligning roller bearing 35
The inner ring 41 has a double row of orbits 40 on the outer peripheral surface, the outer ring 43 has a spherical orbit 42 on the inner peripheral surface, and the multiple wheels rotatably held by the retainer 45 between the inner ring 41 and the outer ring 43. And a row of barrel-shaped rollers 44. The outer race 43 is fitted on the inner peripheral surface of the housing 46, and the inner race 41 has a tapered hole on the inner peripheral side, and is fitted to the roll neck 33 via a tapered sleeve 47. The taper sleeve 47 is fixed in the axial direction by a nut 48. The bearing on the roll neck 34 side has the same configuration.

The components such as the inner ring 41, the outer ring 43, and the rollers 44 of the self-aligning roller bearing 35 are represented by mass% as an alloying element.
C is 0.6% or more and 1.3% or less; Si is 0.3% or more and 3.0% or less; Ni is 0.1% or more and 3.0% or less;
A steel material containing at least 1.0% or more and 2.0% or less of n and at least 0.3% or more and 5.0% or less of Cr. It has a retained austenite of 10% by volume or more.

[0046]

EXAMPLES Examples and comparative examples will be described below. (Examples 1 to 9) Test pieces for evaluating rolling life, peeling and smearing strength obtained by subjecting steels having the seven chemical components shown in Table 1 to a quenching and tempering treatment as described below (executed in Table 1) Examples 1 to 6 and 9) were prepared. Further, test pieces (Examples 7 and 8 in Table 1) obtained by subjecting the steel materials shown in Examples 1 and 3 to carbonitriding were also prepared.

[0047]

[Table 1]

The test piece which is not carbonitrided is 800 ° C. to 85 ° C.
After quenching into oil after heating to 0 ° C, the surface hardness is HRC5
8 or more and the amount of retained austenite in the surface layer is 10% by volume
It was tempered so as to be as described above. In some examples, heating before quenching was performed in a carburizing atmosphere to which ammonia gas was added, and carbonitriding was also performed. Also for the carbonitrided steel, tempering was performed to ensure a residual austenite amount of 10% by volume or more in the surface layer. (Comparative Examples 1 to 12) High carbon chromium bearing steel SUJ2, SU
Test pieces (Comparative Examples 1 to 4 in Table 1) were prepared by quenching and tempering steel having J3 and two kinds of chemical components out of the range of the chemical components of the present application. In addition, test pieces (Comparative Examples 5 to 7 in Table 1) in which some steel materials including SUJ2 shown in Comparative Examples 1 to 4 were subjected to carbonitriding treatment were also prepared. Further, a test piece obtained by quenching and tempering steel having five kinds of chemical components deviating from the chemical component composition of the present application (Comparative Examples 8 to 1 in Table 1)
2) was also prepared.

With respect to the test piece samples of the above Examples and Comparative Examples, a rolling life test (high surface pressure condition and high temperature + contaminant mixing condition), a peeling test and a smearing test were performed.

The outline and results of each test are as follows. (1) Rolling life test at high surface pressure The rolling life test was performed by accelerating the fatigue of the sample under the conditions of high surface pressure and high load speed. The test was performed under the following test conditions. In this test, the number of samples N was set to 10,
Fatigue strength was evaluated based on the L10 life (90% of the sample could be used without breaking).

-Test piece dimensions: outer diameter 12 mm, length 22 mm-Counterpart steel ball dimensions: diameter 19.05 mm-Contact stress Pmax: 5.88 GPa-Load speed: 46240 times / min The test results are shown in Table 2.

[0052]

[Table 2]

In the comparative example, tempering was performed at a normal temperature of 180 ° C., and tempering was performed up to a maximum of 300 ° C. as in the example. From the results in Table 2, it can be seen that the life of the tempered 300 ° C. product of the comparative example is significantly reduced. On the other hand, in Examples, Comparative Examples 1 to 4 which were tempered at 300 ° C., tempered at 180 ° C., and Comparative Examples 5 to 7 which were tempered at 180 ° C. after carbonitriding to reduce the residual austenite to 20% or more.
Longer lifespan than. In Examples 7 and 8 in which carbonitriding treatment was performed to secure retained austenite of 10% or more, 350 ° C.
Irrespective of tempering, the life tends to be longer. Comparative Example 9 shows a long life equivalent to that of the Example, but is a high carbon material and has a large number of large carbides precipitated. Comparative Example 8 deviating from the composition range of the present application on the lower carbon side
Has a short lifespan. (2) Foreign matter contamination test at high temperature The life of foreign matter contamination was examined using a thick flat plate test piece under the following conditions.

・ Plate: Outer diameter φ52, wall thickness t25 (mm) ・ Material: 1/4 ceramic sphere (3 pieces) ・ Contact surface pressure: 6.5 GPa ・ Rotation speed: 2000 rpm (3000 cp at load speed)
m)-Lubrication: Si oil-based heat-resistant oil, oil bath, 25 cc-Foreign matter: Hardness HV800, size 30 to 50 m,
Amount: 0.01 g Temperature: 200 ° C. The test results are shown in Table 2.

The results of the high-temperature rolling life ratio in Table 2 are expressed as a ratio to the life of the SUJ2 standard product. From these results, it can be seen that the comparative example has a low strength at a high temperature and no retained austenite, so that it has no toughness to foreign substances and has a short life. When the carbonitriding treatment is applied to the comparative example, the life is prolonged. However, this is because tempering is performed at 180 ° C., and the dimensional change becomes large at a high temperature, so that this specification cannot be used. In each of the examples, the service life is at least twice as long as that of the comparative example. In particular, those having a large amount of retained austenite (Examples 2 and 3) have a long life.

The carbonitrided product of the example shows a life nearly three times that of the comparative example regardless of the high temperature tempering.

Comparative Examples 9, 10, and 12 show long life, which is due to the effects of high C, high Ni, and high Cr. These cause an increase in cost and a deterioration in workability. In particular, high C and high Cr steels have difficulty in the peeling strength described later. (3) Contaminant contamination test on bearings Using the following tapered roller bearing 30206, the contamination contamination life was examined under the following conditions.

・ Bearing: 30206, inner diameter φ30, outer diameter φ62, assembly width 17.25 ・ Load: 17.64 kN ・ Rotation speed: 2000 rpm ・ Lubrication: turbine oil, oil bath lubrication, oil amount, about 25 cc ・ Foreign matter: hardness HV800, size 100-180μ
m, amount: 0.4 g / L Temperature: 60 ° C. The test results are shown in Table 2.

From the results shown in Table 2, those of the examples are comparative examples 1
It can be seen that the life is three times or more as long as (SUJ2). Further, among the comparative examples, Comparative Example 9 of high C and high Ni,
Although 10 has a long life, these have difficulty in workability.

Although tapered roller bearings are used in this experiment, it is easily presumed that similar effects can be obtained for ball bearings and cylindrical roller bearings. (4) Peeling test In the peeling test, a ring-shaped test piece having a gentle curvature is used as a drive shaft in a cylindrical portion, a driven shaft parallel to the drive shaft is attached, and the cylindrical surfaces of both test pieces are pressed against each other and rolled. To move. The dimensions of each test piece were 40 mm in diameter,
The height is 12 mm, the sub-curvature radius of the cylindrical portion is 60 mm, the cylindrical surface of the test piece on the drive shaft side is ground to a roughness of Rmax 3 μm, and the cylindrical surface of the test piece on the driven shaft side is mirror-finished.
The peeling strength is evaluated by the peeling area ratio of the cylindrical surface of the driven shaft side test piece at the end of the test. This peeling test was performed under the following test conditions.

As the test pieces on both the drive shaft side and the driven shaft side, samples of the same kind were used as a pair.

The maximum surface roughness of the test piece: 3.0 μm (on the drive shaft side),
0.2 μm (on the driven shaft side) ・ Contact surface pressure Pmax: 2.3 GPa ・ Lubricant oil: Turbine oil VG46 ・ Drive shaft rotation speed: 2000 rpm ・ Total rotation speed: 4.8 × 10 ⁵ Test results are shown in Table 2. Also shown.

From the results shown in Table 2, it can be seen that the test pieces of the examples all have an exfoliating strength of 2% or less and exhibit excellent peeling strength. On the other hand, each of the test pieces of the comparative example is the same as the standard heat-treated product in Example 3.
The peeling generation area ratio is twice as large. Although the peel strength of the comparative example is improved by carbonitriding, it is not as high as that of the example without carbonitriding. In Comparative Examples 9 and 12, large carbides are likely to be generated due to the effects of high C and high Cr, and these are sources of stress concentration, and the strength is rather reduced with respect to local microcracks such as peeling. are doing.

In the ninth embodiment, a large carbide is easily generated under the influence of high V, so that the peeling generation area ratio is slightly increased. (5) Smearing test In the smearing test, two ring-shaped test pieces having the same shape as in the peeling test are similarly rolled using the same apparatus as in the peeling test. In this case,
The difference from the peeling test is that the driven shaft is driven to rotate at a constant speed, and the drive shaft is gradually increased in speed from the driven shaft at a constant speed. Further, the point different from the peeling test is that the cylindrical surface of the driven shaft side test piece is finished to the same surface roughness Rmax 3 μm as the drive shaft side test piece. The smearing strength is evaluated based on the speed ratio between the drive shaft and the driven shaft when smearing occurs on the cylindrical surface of the test piece. A smearing test was performed under the following test conditions. In this test, the specimens of the sliding pair were of the same kind.

· Maximum surface roughness of the test piece: 3.0 µm · Contact surface pressure Pmax: 2.1 GPa · Lubricating oil: Turbine oil VG46 · Drive shaft rotation speed: 200 rpm to 100 rpm
Increased speed by m ・ Rotated shaft rotation speed: constant at 200 rpm The test results are also shown in Table 2.

From the results shown in Table 2, it can be seen that smearing does not occur in any of the test pieces of the example up to 1.3 times or more the speed ratio of Comparative Example 1. On the other hand, in each of the test pieces of the comparative example, smearing occurred at a speed difference of about 70% of that of the example when tempered at a high temperature. Also, when carbonitriding in the comparative example, the smearing resistance is slightly improved,
Still, it does not reach the embodiment.

From the results of the above tests, the test pieces of the examples are hardly subject to peeling or smearing, show excellent rolling fatigue characteristics, and are rolling components with slip or tangential force, which are liable to cause surface damage. It can be seen that it has performance suitable for applications where lubricating oil is insufficient.

The embodiments and examples disclosed this time are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

[0069]

As described above, according to the present invention, a long life can be ensured in a rolling bearing used under high temperature conditions and under conditions where surface origin type damage is likely to occur due to foreign matter entrapment or insufficient lubrication. , Transmission, reducer,
The reliability of machine elements such as a paper machine and a rolling mill can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a configuration of a rolling bearing according to an embodiment of the present invention.

FIG. 2 is a schematic sectional view showing a configuration in which the rolling bearing according to the embodiment of the present invention is applied to a manual transmission.

FIG. 3 is a diagram illustrating a structural model of a four-stage hot rolling mill when the rolling bearing according to one embodiment of the present invention is applied to a double row roller bearing.

FIG. 4 is a cross-sectional view showing a configuration of a dryer roll of a paper machine when the rolling bearing according to one embodiment of the present invention is applied to a double row roller bearing.

FIG. 5 is an enlarged partial cross-sectional view showing the bearing unit of FIG. 4;

[Explanation of symbols]

1, 41 inner ring, 2, 43 outer ring, 3 rolling elements, 5 rolling bearings, 10 transmission, 11 input shaft, 12 output shaft, 13 pilot shaft, 14 counter shaft, 21 work roll, 22 backup roll, 21a, 21
b shaft end, 25, 26, 29, 35 double row roller bearing, 3
1 Roll body, 33, 34 Roll neck, 44
Roller.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) F16C 13/02 F16C 13/02 19/28 19/28 19/38 19/38 33/34 33/34 33 / 62 33/62 F term (reference) 3J101 AA13 AA15 AA16 AA32 AA43 AA44 AA52 AA54 AA62 BA70 EA02 FA31 GA36 GA60 3J103 AA02 AA13 AA41 BA09 DA05 DA07 FA14 GA17 GA55 HA08 HA32 4L055 CF01 CG30 EA29 EA32 FA

Claims (7)

[Claims] 1. A part of a rolling bearing having a bearing ring and a rolling element, wherein the part of the rolling bearing has a C content of
Is 0.6% or more and 1.3% or less, and Si is 0.3% or more.
0% or less, Ni is 0.1% or more and 3.0% or less, Mn is 1.0% or more and 2.0% or less, and Cr is 0.3% or more and 5.0% or less.
% Or less, and the amount of retained austenite in the surface layer is 10% by volume or more. 2. The steel material has a mass% as an alloying element,
The rolling bearing component according to claim 1, wherein at least one of V of 0.05% or more and 1.0% or less and Mo of 0.05% or more and less than 0.25% is added. 3. A drive device using the rolling bearing component according to claim 1 or 2. 4. A roll supporting device for a paper machine in which a roll is rotatably supported on a housing by a double-row roller bearing, wherein the parts of the double-row roller bearing have a mass% as an alloying element.
C is 0.6% or more and 1.3% or less; Si is 0.3% or more and 3.0% or less; Ni is 0.1% or more and 3.0% or less;
It is made of a steel material containing at least 1.0% to 2.0% of n and at least 0.3% to 5.0% of Cr, and the residual austenite amount of the surface layer is at least 10% by volume. , Roll supporting device for paper machine. 5. The roll supporting device for a paper machine according to claim 4, wherein the roll is a dryer roll. 6. The roll supporting device for a paper machine according to claim 4, wherein said double row roller bearing is a self-aligning roller bearing. 7. A roll supporting device of a rolling plant in which a roll is rotatably supported on a housing by a double-row roller bearing, wherein a component of the double-row roller bearing is expressed as a mass% as an alloy element,
C: 0.6% to 1.3%, Si: 0.3% to 3.0%, Ni: 0.1% to 3.0%, Mn
1.0% or more and 2.0% or less, and Cr 0.3% or more.
A roll supporting device for rolling equipment, comprising a steel material containing at least 0% or less and having a residual austenite amount of 10% by volume or more in a surface layer.