JP2017122510A - Bearing ring, rolling bearing and method of manufacturing bearing ring - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bearing ring which enables its strength and corrosion resistance to be improved, and which enables its manufacturing processes to be simplified, a rolling bearing comprising the bearing ring, and a method of manufacturing the bearing ring.SOLUTION: A method of manufacturing bearing rings 10, 20 according to the present invention comprises the steps of: compressing metal glass power filled into a metallic mold; and heating the metal glass power to a temperature range between a glass transition temperature and a crystallization temperature of the metal glass powder. Consequently, precipitation of a crystal phase of the structure of the bearing ring can be suppressed, and a bearing ring as a bulk material in a different shape can be formed.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a bearing ring constituting a rolling bearing, a rolling bearing provided with the bearing ring, and a method for manufacturing the bearing ring, and in particular, excellent in corrosion resistance and strength compared to a bearing ring formed of an alloy such as steel. The present invention relates to a bearing ring that is high and that can simplify the manufacturing process, a rolling bearing including the bearing ring, and a method for manufacturing the bearing ring.

In general, the bearing rings (outer ring and inner ring) constituting the rolling bearing are pre-processed to form steel material into an annular material, a turning process to form a raceway groove in the annular material, and the strength and hardness of the annular material. It is formed through a heat treatment process for improving the finish and a finishing process for improving the finishing accuracy of the race.
Specifically, in the previous step, first, a bar-shaped material is formed by cutting a bar made of high carbon steel such as SUJ2 or SUJ3. And an annular material is formed by forging a disk-shaped material.
In the turning process, by turning the annular material, a raceway groove is formed on the circumferential surface (inner circumferential surface or outer circumferential surface) of the annular material, and corners of the annular material are chamfered. . Note that the bottom surface of the raceway groove formed in the annular material becomes the raceway surface with which the rolling elements come into contact.
In the heat treatment step, the annular material is subjected to heat treatment such as quenching and tempering, whereby a hardened layer is formed on the surface of the annular material. As a result, the strength and hardness of the raceway (especially the hardness of the raceway surface) is improved.
In the finishing process, the surface of the annular material is subjected to various finishing processes such as grinding, polishing, and super finishing, so that the finishing accuracy (roundness, etc.) of the raceway is improved and the surface of the raceway surface is improved. Surface roughness is improved. And a raceway ring is completed by passing through a finishing process.

Here, the circularity and the like of the annular material that has undergone the heat treatment process are reduced by thermal deformation. Accordingly, in the finishing process, it is necessary to improve the roundness of the annular material by grinding and then improve the finishing accuracy and surface roughness by polishing, superfinishing, or the like. Therefore, the finishing process includes a plurality of types of finishing processes, which is one of the causes for complicating the manufacturing process of the race.
2. Description of the Related Art Conventionally, for example, a method disclosed in Patent Document 1 is known as a method of manufacturing a bearing ring that aims to simplify the process while improving the finishing accuracy of the bearing ring in the finishing process.
In this method of manufacturing a ring, in the finishing process, as a finishing process, the annular material is subjected to cold rolling forming to correct the deformation of the annular material that has undergone the heat treatment process, and the roundness and surface roughness. Has improved. This eliminates the need for grinding, polishing, super-finishing, etc., and simplifies the finishing process.

JP 2013-56366 A

However, since the conventional method for manufacturing a raceway requires a heat treatment step and a finishing step, the manufacturing step is still complicated.
Moreover, since the conventional bearing ring is formed with alloys, such as steel, there exists a limit in improvement of corrosion resistance and intensity | strength. That is, an alloy such as steel has a crystal grain structure and therefore has grain boundaries in its structure. As a result, the corrosive elements enter the inside through the crystal grain boundaries, and the corrosion tends to proceed along the crystal grain boundaries, and there is a limit to the improvement of the corrosion resistance. In addition, cracks are likely to occur at the grain boundaries, and there is a limit to improving the strength.
An object of the present invention is to provide a race ring having excellent corrosion resistance, high strength, and capable of simplifying the manufacturing process as compared with a race ring formed of an alloy such as steel, and a rolling provided with the race ring. The object is to provide a bearing and a method of manufacturing the race.

In order to solve the above-mentioned problems, a bearing ring according to a first aspect of the present invention is a bearing ring constituting a rolling bearing, wherein the bearing ring is made of metal glass, and the metal glass is made of Ni-Cr-P. It has a composition of any one of -B, Ni-Cr-P-B, Ni-Cr-Nb-P-B, Ni-Nb-Ti, and Ni-Nb-Zr.
The track ring according to the first invention is made of metal glass. As a result, the strength and corrosion resistance can be improved as compared with a bearing ring formed of an alloy such as steel.
In particular, in the race according to the first invention, the metal glass is Ni—Cr—P—B, Ni—Cr—P—B, Ni—Cr—Nb—P—B, Ni—Nb—Ti and Ni—. It has any composition among Nb-Zr. Thereby, in the manufacturing process of the bearing ring, molding in the atmosphere is possible, and the manufacturing process can be simplified.

A rolling bearing according to a second invention is a rolling bearing comprising an outer ring, an inner ring, and a plurality of rolling elements disposed between the outer ring and the inner ring, wherein the outer ring and the inner ring As at least one, the track ring according to the first invention is provided.
According to the rolling bearing which concerns on 2nd invention, compared with the rolling bearing provided with the bearing ring formed with alloys, such as steel, it becomes possible to improve an intensity | strength and corrosion resistance.
In particular, according to the rolling bearing according to the second invention, in the manufacturing process of the outer ring and the inner ring, molding in the atmosphere is possible, and the manufacturing process can be simplified.

A method for manufacturing a bearing ring according to a third aspect of the invention is a method for manufacturing a bearing ring that constitutes a rolling bearing, wherein the metal glass powder filled in a mold is compressed and the glass transition of the metal glass powder is performed. And heating to a temperature region between the temperature and the crystallization temperature.
In the raceway manufacturing method according to the third aspect of the invention, the raceway is formed from metallic glass powder using a powder metallurgy technique. Thereby, precipitation of the crystal phase in the structure of the raceway can be suppressed, and it becomes possible to form the raceway which is an irregularly shaped bulk material.

According to a fourth aspect of the present invention, there is provided a bearing ring manufacturing method according to the third aspect, wherein the maximum particle size of the metal glass powder is 70 μm or less.
According to the track ring manufacturing method of the fourth invention, it is possible to easily perform molding in the mold.
In particular, according to the raceway manufacturing method according to the fourth aspect of the invention, it is possible to improve the accuracy with respect to the mold. As a result, it is possible to improve the finishing precision and surface roughness of the bearing ring by increasing the precision of the mold, so that the finishing process for improving the finishing precision of the bearing ring can be omitted in the manufacturing process. It becomes possible.

  According to the method for manufacturing a bearing ring, a rolling bearing, or a bearing ring according to the present invention, the strength and corrosion resistance can be improved, and the manufacturing process can be simplified.

It is sectional drawing of the rolling bearing which concerns on embodiment of this invention. It is sectional drawing of the outer ring | wheel and inner ring | wheel with which the rolling bearing shown in FIG. 1 is provided. It is sectional drawing of a metal mold apparatus. It is a figure which shows the result of having measured surface roughness Ra, roundness, Vickers hardness, and pressure ring intensity | strength about each of the track ring which concerns on the Example of this invention, and the track ring which concerns on a comparative example.

  Hereinafter, a configuration of a rolling bearing 1 and a method of manufacturing a bearing ring according to an embodiment of the present invention will be described with reference to the drawings.

(Configuration of rolling bearing 1)
FIG. 1 is a cross-sectional view of a rolling bearing according to an embodiment of the present invention. 2 is a cross-sectional view of an outer ring and an inner ring included in the rolling bearing shown in FIG.
As shown in FIG. 1, the rolling bearing 1 includes an outer ring 10, an inner ring 20 disposed inside the outer ring 10, a plurality of rolling elements 30 disposed between the outer ring 10 and the inner ring 20, and a plurality of rolling elements 30. A retainer 40 that holds the rolling element 30 and a pair of seal members 50 that seal between the outer ring 10 and the inner ring 20.

  The outer ring 10 is formed in an annular shape. As shown in FIG. 2, a raceway groove 11 and a pair of seal grooves 12 are formed on the inner peripheral surface of the outer ring 10. The track groove 11 is formed at a position between the pair of seal grooves 12. The raceway groove 11 has a cross section along the width direction formed in an arc shape and is continuous over the entire circumference of the inner peripheral surface of the outer ring 10. The inner surface (bottom surface) of the raceway groove 11 is a raceway surface 11a with which the rolling elements 30 come into contact (roll). Each of the pair of seal grooves 12 has a cross section along the width direction formed in an arc shape, and is continuous over the entire circumference of the inner peripheral surface of the outer ring 10.

The inner ring 20 is formed in an annular shape. As shown in FIG. 2, a raceway groove 21 is formed on the outer peripheral surface of the inner ring 20. The raceway groove 21 has a cross section along the width direction formed in an arc shape and is continuous over the entire circumference of the outer peripheral surface of the inner ring 20. The inner surface (bottom surface) of the raceway groove 21 is a raceway surface 21a with which the rolling elements 30 come into contact (roll).
The plurality of rolling elements 30 are each formed in a spherical shape. In the present embodiment, each rolling element 30 is formed of a steel material such as bearing steel (SUJ2) or stainless steel (SUS440C), ceramic, or the like.

  The cage 40 is formed in an annular shape. In this embodiment, the cage 40 is made of a steel material such as carbon steel (S25C to S55C), stainless steel (SUS304 to SUS316), or mild steel (SS400), or a resin material such as nylon, polyphenylene sulfide, or polyetheretherketone. Is formed. The retainer 40 has a plurality of retaining recesses (not shown). The plurality of holding recesses are arranged at equal intervals along the circumferential direction of the cage 40. And each holding | maintenance recessed part can hold | maintain the one rolling element 30 so that rolling is possible.

  Each of the pair of seal members 50 is formed in an annular shape. In the present embodiment, each seal member 50 is formed of an elastic material such as hydrogenated nitrile rubber or ester acrylic rubber, and a core metal that reinforces the elastic material. Each seal member 50 is fixed to the outer ring 10 by fitting an outer peripheral edge portion thereof to the seal groove 12. Each seal member 50 is a non-contact type seal whose inner peripheral edge is not in contact with the outer peripheral surface of the inner ring 20 even if the inner peripheral edge (lip) is in contact with the outer peripheral surface of the inner ring 20. It doesn't matter which one you have.

In the rolling bearing 1, the inner ring 20 is disposed inside the outer ring 10 with the raceway surface 11 a and the raceway surface 21 a facing each other. And between the track surface 11a and the track surface 21a, the some rolling element 30 is arrange | positioned so that rolling is possible. The plurality of rolling elements 30 are held by the cage 40 and are arranged at equal intervals along the circumferential direction.
In the rolling bearing 1, a lubricant (not shown) is filled between the outer ring 10 and the inner ring 20. As the lubricant, lubricating oil, grease, or the like can be used. The lubricant filled between the outer ring 10 and the inner ring 20 is prevented from flowing out to the outside by the pair of seal members 50.

In particular, in the rolling bearing 1, at least one of the outer ring 10 and the inner ring 20 is formed of metal glass. In the present embodiment, the outer ring 10 and the inner ring 20 are each formed of metal glass.
Metallic glass is an alloy containing three or more kinds of metal elements whose atomic diameters are different from each other by 12% or more, and when heated, a clear glass transition and a relatively wide (about 40 to 130K) excess before crystallization. An alloy having a cooling liquid temperature region.
The metallic glass forming the outer ring 10 and the inner ring 20 is mainly composed of Zr-based metallic glass mainly composed of zirconium (Zr), Fe-based metallic glass mainly composed of iron (Fe), and titanium (Ti). Ti-based metallic glass, Ni-based metallic glass containing nickel (Ni) as a main component, or the like can be used.

In the present embodiment, in order to enable molding in the atmosphere as will be described later, the metallic glass forming the outer ring 10 and the inner ring 20 includes Ni-based metallic glass, particularly nickel (Ni) and niobium (Nb). Ni—Nb-based metallic glass is used.
Examples of the composition of the Ni-based metallic glass include Ni ₅₆ Cr ₂₄ P ₁₆ B ₄ and Ni ₆₅ Cr ₁₅ P ₁₆ B ₄ . As the composition of the Ni-Nb based metallic glass, for _{example, Ni 65 Cr 13 Nb 2 P} 16 B 4, Ni 60 Nb 30 Ti 10, Ni 36 Nb 24 Zr 40 , and the like.
In the rolling bearing 1, each of the plurality of rolling elements 30 may be formed of metal glass. In this case, it is preferable that the component of the metal glass that forms the plurality of rolling elements 30 is the same as the component of the metal glass that forms the races 10 and 20.

(Rolling ring manufacturing method)
Next, a method for manufacturing the bearing rings (the outer ring 10 and the inner ring 20) included in the rolling bearing 1 will be described with reference to the drawings.
The race rings 10 and 20 are a powder manufacturing process for producing a metal glass powder raw material that is a material for forming the race rings 10 and 20, a molding process for forming the race glass 10 and 20 by molding the metal glass powder raw material, Manufactured including

As the metal glass powder raw material, Zr-based metal glass powder, Fe-based metal glass powder, Ti-based metal glass powder, Ni-based metal glass powder and the like can be used.
Here, the Zr-based metallic glass powder has a high amorphous forming ability and is easy to form a large bulk material as compared with metallic glasses having other compositions. However, since the Zr-based metallic glass powder has low corrosion resistance compared to metallic glass powders of other compositions, molding in vacuum is essential in the molding process. In contrast, Ni-based metallic glass powder has higher corrosion resistance than metallic glass powders of other compositions, and thus can be molded in the atmosphere in the molding process. Therefore, in this embodiment, Ni-based metal glass powder, particularly Ni—Nb-based metal glass powder containing nickel (Ni) and niobium (Nb) is used as the metal glass powder raw material.
On the other hand, since the Ni-based metallic glass powder has a lower amorphous forming ability than metallic glass powders of other compositions, the crystal phase is likely to precipitate when an irregularly shaped bulk material such as a ring is formed. Therefore, in this manufacturing method, the annular races 10 and 20 are formed from the powder of Ni-based metallic glass using a powder metallurgy technique. Thereby, precipitation of the crystal phase in the structure of the races 10 and 20 can be suppressed, and the races 10 and 20 that are bulk materials having irregular shapes can be formed.

In the powder manufacturing process, a metal glass powder raw material that is a material for forming the races 10 and 20 is manufactured. Various methods such as a gas atomization method, a water atomization method, and an oil atomization method can be selected as a method for producing the metal glass powder raw material.
Here, in the manufacturing process of the metallic glass powder raw material, it is necessary to rapidly cool the supercooled liquid state metallic glass to a temperature lower than the glass transition temperature of the metallic glass. A crystalline phase precipitates, and the characteristics as a metallic glass are impaired. Therefore, in this embodiment, the water atomization method, which is a method suitable for rapid cooling of the supercooled liquid state metal glass, is selected as a method for producing the metal glass powder raw material. Moreover, according to the water atomization method, a spherical metal glass powder raw material can be obtained.

Specifically, in the powder production process, atomized powder is produced from a mother alloy obtained by melting a material constituting the metal glass powder raw material by a water atomization method. And the desired metal glass powder raw material is obtained by sieving the manufactured atomized powder.
Here, if the maximum particle size of the metal glass powder raw material exceeds 70 μm, molding in the molding process becomes difficult. Therefore, the maximum particle size of the metal glass powder raw material is preferably 70 μm or less.

Next, the metal mold | die used in a formation process is demonstrated.
FIG. 3 is a cross-sectional view of the mold apparatus.
In the molding process, for example, a mold apparatus 60 shown in FIG. 3 is used as a mold. The mold apparatus 60 includes a cylindrical die 61, a lower punch 62 and an upper punch 63 inserted inside the die 61, and a core rod 64 inserted inside the lower punch 62 and upper punch 63. Yes. In the mold apparatus 60, the area surrounded by the inner peripheral surface of the die 61, the outer peripheral surface of the core rod 64, the upper surface of the lower punch 62, and the lower surface of the upper punch 63 is a cavity in which the metal glass powder raw material is compressed and heated. Tee 65.
The die 61 is provided with heating means (not shown) such as a heater. This makes it possible to heat the metal glass in the cavity 65. Further, the core rod 64 is provided with a temperature sensor (not shown) such as a thermocouple. This makes it possible to measure the temperature of the metal glass (metal glass powder raw material) in the cavity 65.

In the forming step, the metal glass powder raw material is formed to form the races 10 and 20. Specifically, the metal glass powder raw material is filled in a mold (cavity 65), the metal glass powder raw material is compressed at a predetermined molding pressure, and a predetermined molding temperature (glass transition temperature (Tg) or higher, Heating to a temperature equal to or lower than the crystallization temperature (Tx). In this embodiment, compression (pressurization) and heating are performed simultaneously. Here, the predetermined molding temperature is set to a temperature included in the supercooled liquid temperature region of the metal glass powder raw material to be molded.
Moreover, in this embodiment, since Ni-Nb group metal glass powder is used as a metal glass powder raw material, it can compress and heat in air | atmosphere.
Furthermore, the Ni—Nb-based metallic glass powder has a glass transition temperature (Tg) of about 350 ° C. and a crystallization temperature (Tx) of about 420 ° C. Thereby, when the said predetermined | prescribed shaping | molding temperature becomes less than 400 degreeC, the fluidity | liquidity of the metal glass which became a supercooled liquid state is bad, and the structure | tissue of a metal glass is not fully densified. Further, when the predetermined molding temperature exceeds 415 ° C., crystallization proceeds in a short time. Therefore, when using Ni-Nb-based metal glass powder as the metal glass powder raw material, the predetermined molding temperature is preferably set to a temperature within the range of 400 ° C or higher and 415 ° C or lower, particularly 410 ° C. .
When the predetermined molding pressure is less than 480 MPa, the oxide film covering the metal glass raw material cannot be broken, and the strength of the race rings 10 and 20 decreases. Therefore, the predetermined molding pressure is preferably set to 480 MPa or more, particularly 500 MPa.
Then, after completion of the compression and heating under the above conditions, the metallic glass in the supercooled liquid state is cooled so as to be lower than the glass transition temperature (Tg) of the metallic glass. Thereafter, the metallic glass formed from the mold is extracted. Thereby, the races 10 and 20 are completed.

(Action / Effect)
In the rolling bearing 1, the race rings 10 and 20 are made of metal glass having an amorphous structure. Thereby, according to the bearing rings 10 and 20, it becomes possible to improve strength and corrosion resistance as compared with the bearing rings formed of an alloy such as steel. Therefore, according to the rolling bearing 1, compared with the rolling bearing provided with the bearing ring formed with alloys, such as steel, it becomes possible to improve an intensity | strength and corrosion resistance.
In particular, in the rolling bearing 1, the race rings 10 and 20 are made of Ni-based metallic glass that is susceptible to self-passivation. Thereby, according to the rolling bearing 1, the corrosion resistance of the bearing rings 10 and 20 can be further improved, and in particular, it can be used under severe conditions such as acidity and in oil.

Moreover, in the manufacturing method of the bearing ring which concerns on this embodiment, the bearing rings 10 and 20 are formed by heating and compressing metal glass powder to a supercooled liquid temperature area | region within a metal mold | die. Here, when the metallic glass is heated to the supercooled liquid temperature region, it changes to a supercooled liquid state that is a viscous fluid. In addition, the metallic glass has less solidification shrinkage than the crystalline metal. As a result, the metallic glass has extremely high transferability to the mold. Therefore, according to the bearing ring manufacturing method according to the present embodiment, it is possible to form the bearing rings 10 and 20 with high accuracy for the mold. Therefore, since the finishing accuracy and surface roughness of the bearing rings 10 and 20 can be improved by increasing the accuracy of the mold, the finishing process for improving the finishing accuracy of the bearing rings 10 and 20 is omitted. Is possible.
Moreover, in the manufacturing method of the raceway ring according to the present embodiment, the metal glass powder is changed into a supercooled liquid state that is a viscous fluid in the mold, which is a disadvantage of the powder metallurgy product using the metal powder. Generation of certain holes can be suppressed. As a result, the strength of the races 10 and 20 can be further improved, and the hardness of the raceways 11a and 21a can be improved. Therefore, a heat treatment step for improving the strength and hardness of the races 10 and 20 can be achieved. Can be omitted.
Furthermore, in the manufacturing method of the raceway ring according to the present embodiment, the formation of the raceway rings 10 and 20 from the powder of metal glass can suppress the precipitation of the crystal phase in the structure of the raceway rings 10 and 20. It is possible to further improve the strength and hardness of the wheels 10 and 20.
As described above, in the bearing ring manufacturing method according to the present embodiment, the heat treatment step and the finishing step can be omitted, and the manufacturing step can be simplified.
In particular, in the method for manufacturing a bearing ring according to the present embodiment, the bearing rings 10 and 20 are formed using Ni-based metallic glass powder. Here, the Ni-based metallic glass is more susceptible to self-passivation and has higher corrosion resistance than metallic glasses having other compositions. Thereby, according to the manufacturing method of the raceway ring concerning this embodiment, a metallic glass powder raw material can be shape | molded in air | atmosphere, and it becomes possible to further simplify a manufacturing process.

Here, since the rolling bearing 1 has high strength, it is suitable for application to a device such as a server fan having a long continuous drive time. Moreover, since the rolling bearing 1 has high corrosion resistance, it is suitable for application to an apparatus used in an environment where there is a high risk of corrosion such as a medical apparatus.
In particular, since the rolling bearing 1 can improve finishing accuracy, the rolling bearing 1 is suitable for being configured as a miniature bearing having an outer diameter (outer diameter of the outer ring 10) of 15 mm or less, particularly 8 mm or less.
Moreover, in the rolling bearing 1, the strength and corrosion resistance of the rolling bearing 1 are further improved by forming each of the outer ring 10, the inner ring 20 and the plurality of rolling elements 30 with metal glass and the cage 40 with resin. It becomes possible.
On the other hand, in the rolling bearing 1, each of the outer ring 10 and the inner ring 20 is formed of metal glass, each of the plurality of rolling elements 30 is formed of ceramic, and the cage 40 is formed of resin. It is possible to improve the strength and corrosion resistance of the rolling bearing 1 while suppressing an increase in cost.

(Modification)
As mentioned above, although embodiment of this invention was described, in the said embodiment, a various change is possible.
For example, in the above embodiment, the bearing ring (rolling bearing) according to the present invention is applied to a ball bearing using a sphere as a rolling element. However, the bearing ring (rolling bearing) according to the present invention may be applied to other types of rolling bearings such as a roller bearing, a tapered roller bearing, a needle bearing, and a thrust bearing.
Moreover, in the said embodiment, the rolling element 30 is formed with steel materials, and the holder | retainer 40 is formed with steel materials or resin. However, at least one of the rolling elements 30 and the retainer 40 may be formed of metal glass in the same manner as the races 10 and 20.

(Example)
Next, examples of the present invention will be described.
FIG. 4 is a diagram showing the results of measuring the surface roughness Ra, roundness, Vickers hardness, and pressure ring strength for each of the raceway according to the example of the present invention and the raceway according to the comparative example.
As an example of the present invention, using a metal glass powder raw material of Ni ₆₅ Cr ₁₃ Nb ₂ P ₁₆ B _4, a race ring was formed by the race ring manufacturing method according to the above embodiment. At this time, in the powder manufacturing process, a metal glass powder raw material having a particle size range of 30 μm to 60 μm was formed by a water atomization method. In the molding step, the predetermined glass forming temperature was set to 410 ° C., and the predetermined molding pressure was set to 500 MPa to mold the metal glass powder raw material. And the surface roughness Ra, roundness, Vickers hardness, and crushing strength were measured about the bearing ring which concerns on the Example of this invention.
In addition, as a bearing ring according to the comparative example, a general bearing ring made of bearing steel (SUJ2) was prepared. The bearing ring according to the comparative example is manufactured by a conventional manufacturing method (a manufacturing method having a heat treatment step and a finishing step).
As shown in FIG. 4, the bearing ring according to the embodiment of the present invention has the same surface roughness Ra as compared with the bearing ring according to the comparative example manufactured through the finishing process, and is true. The circularity is high. In particular, the raceway according to the embodiment of the present invention can achieve the same roundness as that of the mold.
Therefore, it can be seen that the bearing ring according to the embodiment of the present invention has very high accuracy with respect to the mold. Therefore, by increasing the accuracy of the mold, the finishing accuracy and surface roughness of the bearing ring can be improved, so that the finishing process for improving the finishing accuracy of the bearing ring can be omitted in the manufacturing process. It turns out that it becomes.

Moreover, the bearing ring according to the example of the present invention and the bearing ring according to the comparative example were immersed in a corrosive liquid, and the progress of corrosion according to the immersion time was observed. At this time, 5% / wt salt water was used as the corrosive liquid. And a bearing ring according to an embodiment of the present invention immersed in a corrosive liquid for 3 hours, a bearing ring according to a comparative example immersed in a corrosive liquid for 3 hours, a bearing ring according to an embodiment of the present invention immersed in a corrosive liquid for 33 hours, And the bearing ring which concerns on the comparative example immersed for 33 hours in corrosive liquid was prepared, and the degree of corrosion on the surface and each inside of each bearing ring was observed visually. The degree of corrosion inside each track was observed by observing a cut surface (cross section cut along the direction along the cylindrical axis) of each track.
As a result, corrosion was observed on a part of the surface of the bearing ring according to the comparative example immersed in the corrosive liquid for 3 hours. Further, in the bearing ring according to the comparative example immersed in the corrosive liquid for 33 hours, corrosion in a wide range of the surface was observed, and it was observed that the corrosion reached the inside (substantially the entire area in the thickness direction).
On the other hand, no corrosion on the surface and inside was observed in the bearing ring according to the embodiment of the present invention immersed in the corrosive liquid for 3 hours and the bearing ring according to the embodiment of the present invention immersed in the corrosive liquid for 33 hours.
Therefore, it can be seen that the bearing ring according to the embodiment of the present invention has high corrosion resistance.

DESCRIPTION OF SYMBOLS 1 Rolling bearing 10 Outer ring 11 Raceway groove 11a Raceway surface 12 Seal groove 20 Inner ring 21 Raceway groove 21a Raceway surface 30 Rolling body 40 Cage 50 Seal member 60 Mold apparatus 61 Die 62 Lower punch 63 Upper punch 64 Core rod 65 Cavity

Claims (4)

A bearing ring constituting a rolling bearing,
The bearing ring is formed of metal glass,
The metallic glass has a composition of any one of Ni—Cr—P—B, Ni—Cr—P—B, Ni—Cr—Nb—P—B, Ni—Nb—Ti, and Ni—Nb—Zr. A bearing ring characterized by having. A rolling bearing comprising an outer ring, an inner ring, and a plurality of rolling elements disposed between the outer ring and the inner ring,
A rolling bearing comprising the bearing ring according to claim 1 as at least one of the outer ring and the inner ring. A method of manufacturing a bearing ring constituting a rolling bearing,
A method of manufacturing a bearing ring, comprising a step of compressing a metal glass powder filled in a mold and heating the metal glass powder to a temperature region between a glass transition temperature and a crystallization temperature of the metal glass powder. . The method for manufacturing a bearing ring according to claim 3, wherein the maximum particle size of the metal glass powder is 70 μm or less.

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