JP5455031B2 - Manufacturing method of bearing ring and manufacturing method of rolling bearing - Google Patents

Description

  The present invention relates to a method of manufacturing a bearing ring and a method of manufacturing a rolling bearing, and more specifically, while suppressing the manufacturing cost of the quenching device, the quench hardened layer is formed along the rolling surface by induction hardening. And a method for manufacturing a bearing ring and a rolling bearing capable of forming a hardened hardened layer along a mating surface by induction hardening.

  Induction hardening may be employed as a hardening treatment for the rolling rings of rolling bearings made of steel. This induction hardening can simplify the equipment and heat treatment in a short time compared to the general quench hardening process in which the race is heated in the furnace and then immersed in a coolant such as oil. It has the advantage of becoming.

  However, in induction hardening, in order to simultaneously heat the annular region to be hardened and hardened along the raceway surface of the raceway, it is necessary to inductively heat the raceway so as to face the raceway surface. It is necessary to arrange an induction heating member such as a coil. For this reason, when quenching and hardening a large race, a large coil corresponding to that and a large-capacity power source corresponding to the coil are required, which increases the production cost of the quenching apparatus.

As a measure for avoiding such a problem, there is a case where moving quenching using a small induction heating coil is employed. In this moving quenching, high-frequency induction heating is performed using a coil that is arranged to face a part of an annular region to be heated in the raceway and relatively moves along the region, and is heated. On the other hand, the region is sequentially hardened by jetting a coolant such as water immediately after passing through the coil. However, when this moving quenching is simply adopted, the coil turns once from the quenching start area (quenching start area) and finally quenches the area where quenching should be performed (quenching end area). When hardening, the quenching start area and the quenching end area partially overlap. For this reason, there is a concern about occurrence of quench cracks due to re-quenching of the overlapped region. The region adjacent to the overlapping region, since it is tempered by being heated to a temperature of less than ₁ point A along with the heating of the quenching termination region, there is a possibility that the hardness is lowered. Therefore, when moving quenching is employed, it is common to take measures to leave a region (soft zone) where quenching is not performed between the quenching start region and the quenching end region. This soft zone has low yield strength due to low hardness, and insufficient wear resistance. Therefore, when a soft zone is formed on the race, it is necessary to consider that the soft zone does not become a load region.

  On the other hand, after carrying out the above moving quenching to form a soft zone, a method has been proposed in which a region corresponding to the soft zone is excised and a hardened plug body is fitted in the region (for example, , See Patent Document 1). Thereby, it can avoid that the soft zone with low hardness remains.

  In addition, a method of avoiding the formation of a soft zone by using two coils that move in opposite directions in the circumferential direction of the raceway has been proposed (see, for example, Patent Document 2). In this method, the quenching is started in a state where the two coils are arranged adjacent to each other, and the quenching is finished at a position where the two coils meet again, thereby avoiding the formation of a soft zone and re-quenching. It is also possible to avoid the occurrence of a region to be generated.

JP-A-6-17823 JP-A-6-2003326

  However, the method disclosed in Patent Document 1 has a problem that the number of man-hours for manufacturing the race is significantly increased. Further, in the method disclosed in Patent Document 2, the residual stress accompanying quench hardening is concentrated in the region that is finally quenched, and there is a concern about the occurrence of heat treatment distortion and quench cracking.

  Moreover, when a raceway ring is used by being fitted to another member, high hardness may be required for a fitting surface that is a surface in contact with the other member. On the other hand, in a race ring in which a hardened hardened layer (rolling surface hardened layer) is formed by induction hardening in a region including the rolling surface, in order to give the fitting surface high hardness, It is necessary to form a hardened hardened layer (fitting surface hardened layer) for the region to be included. However, in order to form the rolling surface quenching layer and the mating surface quenching layer at the same time, there is a problem that the structure of the quenching apparatus becomes complicated and the manufacturing cost of the apparatus increases. In addition, when one of the rolling surface quenching layer and the mating surface quenching layer is formed and then adopting the process of forming the other, the previously formed quenching layer is formed at the time of subsequent quenching layer formation. There arises a problem that the hardness is lowered due to tempering by heating.

  Accordingly, an object of the present invention is to form a quench-hardened layer uniformly along the rolling surface by induction hardening while reducing the manufacturing cost of the quenching device, and to reduce the hardness of the rolling surface. It is to provide a bearing ring for a rolling bearing and a method for manufacturing the rolling bearing capable of forming a hardened hardened layer on the mating surface while suppressing the above.

The method for manufacturing a bearing ring according to the present invention is a method for manufacturing a bearing ring for a rolling bearing. This method of manufacturing a bearing ring includes a step of preparing a molded body made of steel, and the molded body is arranged so as to face a part of an annular region to be a rolling surface of the bearing ring, thereby guiding the molded body. A process of forming an annular heating region heated to a temperature of _one point A or more on the formed body by relatively rotating the induction heating member to be heated along the circumferential direction of the annular region, and the entire heating region By simultaneously cooling to a temperature not higher than the M _S point, the process of forming the rolling surface hardened layer over the entire circumference along the annular region, and a part of the region to be the mating surface of the bearing ring in the molded body The other induction heating member that is arranged so as to face and induction-heats the molded body is relatively moved along the circumferential direction of the region to be the fitting surface, and the other induction heating member is driven. By cooling member, other induction heating member And a step of forming a mating surface hardened layer by cooling the heated region I.

In the method for manufacturing a raceway ring according to the present invention, the induction heating member arranged so as to face a part of the annular region to be a rolling surface relatively rotates along the circumferential direction, thereby forming a molded body. A heating region is formed. Therefore, it is possible to employ a small induction heating member with respect to the outer shape of the race. As a result, the manufacturing cost of the quenching device can be suppressed even when a large raceway is quenched and hardened. In the method for manufacturing a bearing ring according to the present invention, the entire heating region is simultaneously cooled to a temperature below the _MS point. Therefore, it is possible to simultaneously form a hardened hardened layer along the rolling surface over the entire circumference, and the residual stress is suppressed from being concentrated in a part of the region.

  Furthermore, in the method for manufacturing a raceway ring according to the present invention, another induction heating member that is arranged so as to face a part of the region to be the fitting surface and induction-heats the molded body should be the fitting surface. The mating surface hardened layer is formed by cooling the region heated by the other induction heating member with the cooling member that moves the other induction heating member relative to each other along the circumferential direction of the region. It is formed. Unlike the rolling surface, the fitting surface does not necessarily need to form a hardened and hardened layer over the entire circumference, and a region where the hardened and hardened layer is not formed may be formed in a part of the circumferential direction. Therefore, it is possible to form a mating surface hardened layer by moving quenching as described above. Further, in the above moving quenching, since the region heated by the induction heating member is cooled by the cooling member immediately after the heating, the previously formed rolling surface quenching layer is fitted to form the surface quenching layer. It is also possible to prevent the hardness from being tempered by heating at the time, and to decrease the hardness.

  As described above, according to the method for manufacturing a bearing ring of the present invention, while suppressing the manufacturing cost of the quenching device, the quench hardening layer is uniformly formed along the rolling surface along the rolling surface by induction hardening. Further, it is possible to form a hardened and hardened layer on the mating surface while suppressing a decrease in hardness of the rolling surface.

Note that the _point A when heated steel refers to a point that the structure of the steel corresponds to the temperature to start the transformation from ferrite to austenite. Further, the M _s point means a point corresponding to a temperature at which martensite formation starts when the austenitized steel is cooled.

  The method for manufacturing a bearing ring may further include a step of performing a normalizing process on the molded body before the step of forming the heating region.

  In a raceway ring manufactured by induction hardening and a region including a rolling surface and a region including a mating surface being partially quenched and hardened, a predetermined strength is provided even in a region that is not hardened (non-hardened region). It is necessary to have sufficient hardness. And in order to ensure predetermined | prescribed hardness in a non-hardening area | region, after performing the quenching process to the whole molded object (track ring) before an induction hardening process, you may implement a tempering process further. However, when steel having a relatively high carbon content and a high hardenability component composition is adopted as a material, there is a problem that quench cracking is likely to occur. On the other hand, in a molded body made of steel having such a component composition, sufficient hardness can be ensured by normalizing treatment. Therefore, instead of securing the hardness by the quenching and tempering, an appropriate hardness can be imparted to the non-cured region by performing the normalizing treatment before the induction hardening.

  In the above-described method for manufacturing a bearing ring, in the step of performing the normalizing process, the shot blasting process may be performed while the molded body is cooled by spraying hard particles together with gas on the molded body.

  Thus, the shot blasting process can be performed simultaneously with the gust cooling at the normalizing process. Therefore, the scale generated in the surface layer portion of the compact is removed by the heating of the normalizing process, and the deterioration of the characteristics of the raceway due to the generation of the scale and the decrease of the thermal conductivity due to the generation of the scale are suppressed.

In the above-described method for manufacturing a race, the race may include a double row rolling surface. In this case, in the step of forming a rolling surface hardened layer, it is preferable that the heating region of the double row is cooled M _S point below the temperature at the same time.

When the raceway includes double-row rolling surfaces, after forming a rolling surface hardened layer on one rolling surface, a rolling surface hardened layer on the other rolling surface is formed first. The rolled surface hardened layer may be tempered by the heating accompanying the formation of the rolled surface hardened layer to be formed later, and the hardness may decrease. In contrast, by heating areas of the double row is formed rolling surfaces hardened layer is cooled to M _S point below the temperature at the same time, decrease in the hardness of the rolling surface hardening layer is avoided.

  In the method for manufacturing a bearing ring, in the step of forming the heating region, the induction heating member may relatively rotate two or more times along the circumferential direction of the molded body. Thereby, the dispersion | variation in the temperature in the circumferential direction of a rolling surface can be suppressed, and homogeneous quench hardening can be implement | achieved.

  In the above-described method for manufacturing a race, a plurality of induction heating members may be arranged along the circumferential direction of the molded body in the step of forming the heating region. Thereby, the dispersion | variation in the temperature in the circumferential direction of a rolling surface can be suppressed, and homogeneous quench hardening can be implement | achieved.

  In the method for manufacturing a race, the temperature at a plurality of locations in the heating region may be measured in the step of forming the heating region. Thereby, after confirming that homogeneous heating has been realized in the circumferential direction of the rolling surface, quenching and hardening can be performed. As a result, uniform quenching hardening can be realized in the circumferential direction of the rolling surface.

  In the method for manufacturing a bearing ring, in the step of preparing a molded body, 0.43% to 0.65% carbon, 0.15% to 0.35% silicon, Containing from 60 mass% to 1.10 mass% manganese, from 0.30 mass% to 1.20 mass% chromium, and from 0.15 mass% to 0.75 mass% molybdenum, A formed body made of steel composed of the remaining iron and impurities may be prepared.

  Further, in the method of manufacturing the race, in the step of preparing the molded body, 0.43% to 0.65% carbon, 0.15% to 0.35% silicon, 0.60% by mass to 1.10% by mass manganese, 0.30% by mass to 1.20% by mass chromium, 0.15% by mass to 0.75% by mass molybdenum, A molded body that includes .35 mass% or more and 0.75 mass% or less of nickel and that is made of steel composed of the remaining iron and impurities may be prepared.

  By adopting steel having such a component composition as a raw material, sufficiently high hardness can be realized by quench hardening, and quench cracking can be suppressed while ensuring high hardenability.

  Here, the reason why it is preferable to set the component range of steel constituting the formed body, that is, the component range of steel constituting the manufactured bearing ring, to the above range will be described.

Carbon: 0.43 mass% or more and 0.65% mass% or less The carbon content greatly affects the hardness of the raceway of the raceway after quench hardening. If the carbon content of the steel constituting the bearing ring is less than 0.43 mass%, it may be difficult to impart sufficient hardness to the rolling surface after quench hardening. On the other hand, when the carbon content exceeds 0.65% by mass, there is a concern about generation of cracks (quenching cracks) during quench hardening. Therefore, the carbon content is preferably 0.43% by mass or more and 0.65% by mass or less.

Silicon: 0.15 mass% or more and 0.35 mass% or less Silicon contributes to the improvement of the temper softening resistance of steel. When the silicon content of the steel constituting the raceway is less than 0.15% by mass, the temper softening resistance becomes insufficient, and the rolling surface of the raceway surface is increased due to tempering after quench hardening and temperature rise during use of the raceway. Hardness can be significantly reduced. On the other hand, if the silicon content exceeds 0.35% by mass, the hardness of the material before quenching increases, and the workability in cold working when forming the material into a raceway ring may be reduced. Therefore, the silicon content is preferably 0.15% by mass or more and 0.35% by mass or less.

Manganese: 0.60% by mass or more and 1.10% by mass or less Manganese contributes to improvement of hardenability of steel. If the manganese content is less than 0.60% by mass, this effect cannot be sufficiently obtained. On the other hand, if the manganese content exceeds 1.10% by mass, the hardness of the material before quenching increases, and the workability in cold working decreases. Therefore, the manganese content is preferably 0.60% by mass or more and 1.10% by mass or less.

Chromium: 0.30% by mass or more and 1.20% by mass or less Chromium contributes to improvement of hardenability of steel. If the chromium content is less than 0.30% by mass, this effect cannot be sufficiently obtained. On the other hand, when the chromium content exceeds 1.20% by mass, there arises a problem that the material cost increases. Therefore, the chromium content is preferably 0.30% by mass or more and 1.20% by mass or less.

Molybdenum: 0.15 mass% or more and 0.75 mass% or less Molybdenum also contributes to improving the hardenability of the steel. If the molybdenum content is less than 0.15% by mass, this effect cannot be sufficiently obtained. On the other hand, when the molybdenum content exceeds 0.75% by mass, there arises a problem that the material cost increases. Therefore, the molybdenum content is preferably 0.15% by mass or more and 0.75% by mass or less.

Nickel: 0.35 mass% or more and 0.75 mass% or less Nickel also contributes to improvement of hardenability of steel. Nickel can be added when particularly high hardenability is required for the steel constituting the bearing ring, such as when the outer shape of the bearing ring is large. If the nickel content is less than 0.35% by mass, the effect of improving hardenability cannot be obtained sufficiently. On the other hand, if the nickel content exceeds 0.75% by mass, the amount of retained austenite after quenching increases, which may cause a decrease in hardness and a decrease in dimensional stability. Therefore, it is preferable that nickel is added to the steel constituting the race in a range of 0.35 mass% to 0.75 mass%.

  The manufacturing method of a rolling bearing according to the present invention includes a step of preparing a bearing ring, a step of preparing a rolling element, and a step of assembling the rolling bearing by combining the bearing ring and the rolling element. And the bearing ring is manufactured by the manufacturing method of the bearing ring of the said invention.

  By manufacturing the bearing ring by the above-described manufacturing method of the bearing ring of the present invention, according to the rolling bearing manufacturing method of the present invention, the hardened hardened layer is homogenized along the entire rolling surface by induction hardening. A rolling bearing provided with a bearing ring that is formed and has a hardened hardened layer formed on the mating surface while suppressing a decrease in hardness of the rolling surface can be manufactured at low cost.

  In the method of manufacturing a rolling bearing, the rolling bearing is used as a rolling bearing for a wind power generator that rotatably supports a main shaft connected to a blade with respect to a member adjacent to the main shaft in a wind power generator. There may be. As described above, the method of manufacturing a rolling bearing according to the present invention that can form a hardened hardened layer in a region including a rolling surface and a mating surface of a large-sized bearing ring at low cost is a method for manufacturing a rolling bearing for a wind turbine generator. It is suitable as a method.

  As is apparent from the above description, the method of manufacturing the bearing ring and the rolling bearing according to the present invention reduces the manufacturing cost of the quenching device, and the quench hardening layer is formed along the rolling surface by induction hardening. It is possible to provide a method of manufacturing a bearing ring and a rolling bearing capable of forming a hardened and hardened layer on a mating surface while suppressing a decrease in hardness of the rolling surface.

It is a flowchart which shows the outline of the manufacturing method of the outer ring | wheel of a rolling bearing and a rolling bearing. It is the schematic for demonstrating a rolling surface quench hardening process. It is a schematic sectional drawing which shows the cross section along line segment III-III of FIG. It is the schematic for demonstrating a fitting surface hardening hardening process. It is a schematic sectional drawing which shows the cross section along line segment VV of FIG. It is a schematic sectional drawing which shows the structure of a double row tapered roller bearing. It is a schematic fragmentary sectional view which expands and shows the principal part of FIG. FIG. 5 is a schematic diagram for explaining a quench hardening process in a second embodiment. FIG. 6 is a schematic diagram for explaining a quench hardening process in a third embodiment. It is the schematic which shows the structure of the wind power generator provided with the rolling bearing for wind power generators. It is a schematic sectional drawing which expands and shows the periphery of the spindle bearing in FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated.

(Embodiment 1)
First, Embodiment 1 which is one embodiment of the present invention will be described. Hereinafter, although the manufacturing method of an outer ring will be mainly described as a manufacturing method of a race, the inner ring can be manufactured in the same manner.

  Referring to FIG. 1, in the outer ring manufacturing method according to the present embodiment, a molded body preparation step is first performed as a step (S10). In this step (S10), a steel material having an arbitrary composition suitable for induction hardening, for example, 0.43% to 0.65% carbon, and 0.15% to 0.35% by mass. The following silicon, 0.60 mass% or more and 1.10 mass% or less manganese, 0.30 mass% or more and 1.20 mass% or less chromium, 0.15 mass% or more and 0.75 mass% or less A steel material containing molybdenum and the balance iron and impurities is prepared, and by performing processing such as forging and turning, a molded body having a shape corresponding to the shape of a desired outer ring is produced. More specifically, a molded body corresponding to the shape of the outer ring having an inner diameter of 1000 mm or more is produced. Here, when the outer ring to be manufactured is particularly large and steel requires high hardenability, a steel material added with 0.35 mass% or more and 0.75 mass% or less of nickel in addition to the above alloy components is employed. Also good. Examples of the steel satisfying the above component composition include JIS standard SUP13, SCM445, SAE standard 8660H and the like.

Next, a normalizing step is performed as a step (S20). In this step (S20), after the fabricated molded body is heated to a temperature not lower than the A ₁ transformation point in the step (S10), the normalizing process by being cooled to a temperature below the A ₁ transformation point implementation Is done. At this time, the cooling rate at the time of cooling in the normalizing process may be a cooling rate at which the steel constituting the formed body is not transformed into martensite, that is, a cooling rate lower than the critical cooling rate. The hardness of the molded body after the normalizing treatment is high when the cooling rate is large, and is low when the cooling rate is small. Therefore, desired hardness can be imparted to the molded body by adjusting the cooling rate.

  Next, with reference to FIG. 1, a rolling surface quench hardening process is implemented. This rolling surface quench hardening process includes an induction heating process implemented as a process (S30) and a cooling process implemented as a process (S40). In step (S30), referring to FIG. 2 and FIG. 3, coil 21 as an induction heating member is rolling surface 11A (annular region) that is a surface on which rolling element should roll in molded body (outer ring) 10. It is arranged to face a part of. Here, two coils 21 are arranged so as to face each of the two rows of rolling surfaces.

Next, the molded body 11 is rotated around the central axis, specifically in the direction of the arrow α, and a high frequency current is supplied to the coil 21 from a power source (not shown). Thus, a surface layer region including the raceway surface 11A of the body 11 is inductively heated to a temperature above _a point A, an annular heating region 11C along the rolling surface 11A is formed. At this time, the temperature of the rolling surface 11A is measured and managed by a thermometer 22 such as a radiation thermometer.

Next, in the step (S40), for example, water as a cooling liquid is sprayed onto the entire molded body 11 including the heating region 11C formed in the step (S30) to thereby form two rows of heating regions 11C. The whole is simultaneously cooled to a temperature below the M _S point. As a result, the heating region 11C is transformed into martensite and hardens to become the rolling surface hardened layer 11C. By the above procedure, induction hardening is performed and the rolling surface hardening process is completed.

Next, a fitting surface hardening process is performed as a process (S50). In this step (S50), a region including the fitting surface 11B in the molded body 11 is hardened and hardened. Specifically, referring to FIG. 4 and FIG. 5, first, moving quenching provided with a coil 23 that is an induction heating member and a coolant injection unit 24 that is a cooling member disposed adjacent to the coil 23. The device 25 is arranged so as to face a part of the mating surface 11B. Next, the moving quenching device 25 moves in the circumferential direction (in the direction of arrow β) along the fitting surface 11B. At this time, a high frequency current is supplied to the coil 23 from a power source (not shown). Thus, the region facing the coil 23 of the mating surface 11B of the body 11 is inductively heated to a temperature above _a point A. On the other hand, the cooling liquid is injected from the cooling liquid injection unit 24 toward the fitting surface 11B of the molded body 11. As a result, region derived heated to a temperature higher than A ₁ point by the coil 23 of the fitting surface 11B is cooled to a temperature below M _S point by coolant ejected from the coolant ejector 24, quenching Cured. Then, such a quench hardening process is sequentially performed as the moving quenching apparatus 25 moves, so that the mating surface quenching layer 11D is formed as shown in FIG.

Next, a tempering step is performed as a step (S60). In this step (S60), the molded body 11 partially quenched and hardened in steps (S30) to (S50) is charged into, for example, a furnace and heated to a temperature of A ₁ point or less for a predetermined time. By being held, a tempering process is performed.

  Next, a finishing step is performed as a step (S70). In this step (S70), for example, finishing such as polishing is performed on the rolling surface 11A. The outer ring 11 is completed by the above process, and the manufacture of the outer ring in the present embodiment is completed. As a result, an outer ring 11 having an inner diameter of 1000 mm or more and having the rolling surface hardened layer 11C formed uniformly along the rolling surface 11A by induction hardening is completed.

  Furthermore, an assembly process is performed as a process (S80). In this step (S80), the outer ring 11 produced as described above and the inner ring 12 produced in the same manner as the outer ring 11 are combined with separately prepared rollers 13, a cage 14, etc., for example, The double row tapered roller bearing 1 shown in FIG. 6 is assembled. With the above procedure, the rolling bearing manufacturing method in the present embodiment is completed.

  Here, referring to FIG. 6, a double row tapered roller bearing 1 which is a rolling bearing in the present embodiment includes an annular outer ring 11, two annular inner rings 12 arranged inside the outer ring 11, and an outer ring. 11 and a plurality of tapered rollers 13 disposed between the inner ring 12 and the inner ring 12. Two rows of outer ring rolling surfaces 11 </ b> A are formed on the inner peripheral surface of the outer ring 11, and one row of inner ring rolling surfaces 12 </ b> A are formed on the outer peripheral surfaces of the two inner rings 12. The inner ring rolling surface 12A of one inner ring 12 is opposed to one outer ring rolling surface 11A, and the inner ring rolling surface 12A of the other inner ring 12 is opposed to the other outer ring rolling surface 11A. The outer ring 11 and the two inner rings 12 are arranged. Further, the plurality of tapered rollers 13 are in contact with the outer ring rolling surface 11A and the inner ring rolling surface 12A along each of the outer ring rolling surfaces 11A, and are held by the cage 14 at a predetermined pitch in the circumferential direction. By being arranged, it is held so as to be able to roll on two rows of circular orbits. With the above configuration, the outer ring 11 and the inner ring 12 of the double-row tapered roller bearing 1 are rotatable relative to each other.

  Further, referring to FIGS. 6 and 7, outer ring 11 and inner ring 12 have an inner diameter of 1000 mm or more. The outer ring 11 and the inner ring 12 are rolling surfaces formed over the entire circumference along the rolling surfaces 11A and 12A so as to include the rolling surfaces 11A and 12A that are the surfaces on which the rollers 13 that are rolling elements should roll. The mating surface quenching layers 11D and 12D formed along the mating surfaces 11B and 12B so as to include the quenching layers 11C and 12C and the mating surfaces 11B and 12B mating with other members such as a housing and a shaft. And non-hardened regions 11E and 12E formed between the rolling surface hardened layers 11C and 12C and the mating surface hardened layers 11D and 12D. And the thickness of the fitting surface hardened layers 11D and 12D is smaller than the thickness of the rolling surface hardened layers 11C and 12C.

In the manufacturing method of the raceway ring (outer ring 11) in the present embodiment, the coil 21 that is an induction heating member arranged so as to face a part of the annular region to be the rolling surface 11A is along the circumferential direction. By relatively rotating, a heating region 11 </ b> C is formed in the molded body 11. Therefore, the coil 21 can be downsized to reduce the manufacturing cost of the quenching apparatus. Further, in the present embodiment, the entire heating region is simultaneously cooled to a temperature equal to or lower than the _MS point, so that a hardened and hardened layer can be formed simultaneously over the entire circumference, and residual stress is concentrated in some regions. Is suppressed. Furthermore, in the present embodiment, since the mating surface hardened layer 11D is formed by moving quenching as described above, the region heated by the coil 23 is cooled by the cooling member 24 immediately after heating. The hardness reduction of the rolling surface hardened layer 11C formed earlier is suppressed. As a result, according to the raceway manufacturing method of the present embodiment, the rolling surface hardened layer 11C is uniformly formed over the entire circumference by induction hardening while suppressing the manufacturing cost of the quenching device, and the rolling is performed. The fitting surface hardened layer 11D can be formed while suppressing a decrease in the hardness of the running surface 11A. Further, according to the method for manufacturing a rolling bearing in the present embodiment, the rolling surface hardened layer 11C is formed uniformly over the entire circumference along the rolling surface 11A by induction hardening, and the rolling surface 11A is formed. The double-row tapered roller bearing 1 including the race ring in which the mating surface hardened layer 11D is formed along the mating surface 11B while suppressing the decrease in hardness can be manufactured at low cost.

  In addition, the normalizing process implemented as said process (S20) is not an essential process in the manufacturing method of the bearing ring of this invention, However, Implementing this suppresses generation | occurrence | production of a burning crack, JIS specification. The hardness of the molded body made of steel such as SUP13, SCM445, SAE standard 8660H can be adjusted.

  In this step (S <b> 20), the shot blasting process may be performed while the molded body 11 is cooled by spraying hard particles together with gas on the molded body 11. Thereby, since the shot blasting process can be performed simultaneously with the blast cooling during the normalizing process, the scale generated in the surface layer portion of the molded body 11 is removed, and the characteristics of the outer ring 11 resulting from the generation of the scale are removed. The decrease in thermal conductivity due to the decrease and scale generation is suppressed. Here, as hard particle | grains (projection material), the metal particle | grains which consist of steel, cast iron, etc. are employable, for example.

  In the step (S30), the molded body 11 may be rotated at least once. However, in order to suppress temperature variation in the circumferential direction and achieve more uniform quench hardening, the molded body 11 may be rotated a plurality of times. preferable. That is, it is preferable that the coil 21 as the induction heating member relatively rotate two or more times along the circumferential direction of the rolling surface 11A of the molded body 11.

  Further, in the outer ring 11 and the inner ring 12, uncured regions 11E and 12E are formed between the rolling surface hardened layers 11C and 12C and the mating surface hardened layers 11D and 12D, and the mating surface hardened. The thickness of the layers 11D and 12D is smaller than the thickness of the rolling surface hardened layers 11C and 12C. Thereby, the durability with respect to rolling fatigue of the outer ring 11 and the inner ring 12 is further improved. Here, the thickness of the hardened layer, that is, the thickness of the region heated by induction heating can be adjusted by adjusting the frequency of the current supplied to the coil, the output of the power source, and the like.

(Embodiment 2)
Next, Embodiment 2 which is another embodiment of the present invention will be described. The manufacturing method of the outer ring in the second embodiment is basically performed in the same manner as in the first embodiment, and has the same effect. However, the outer ring manufacturing method in the second embodiment is different from the first embodiment in the arrangement of the coil 21 in the step (S30).

That is, referring to FIG. 8, in the step (S30) in the second embodiment, a pair of coils 21 is arranged as an induction heating member. And while the molded object 11 rotates in the direction of arrow (alpha), the high frequency current is supplied with respect to the coil 21 from a power supply (not shown). Thus, a surface layer region including the raceway surface 11A of the body 11 is inductively heated to a temperature above _a point A, an annular heating region 11C along the rolling surface 11A is formed.

  Thus, the manufacturing method of the outer ring | wheel 11 of the rolling bearing in Embodiment 2 is the circumferential direction by arrange | positioning multiple coils 21 along the circumferential direction of the molded object 11 (two in this Embodiment). This is a method for manufacturing a raceway ring that can suppress temperature variation in the steel and achieve homogeneous quench hardening. Further, in order to further suppress the variation in temperature in the circumferential direction, the coils 21 are preferably arranged at equal intervals in the circumferential direction of the molded body 11.

(Embodiment 3)
Next, Embodiment 3 which is still another embodiment of the present invention will be described. The inner ring manufacturing method according to the third embodiment is basically performed in the same manner as in the first and second embodiments, and has the same effects. However, the inner ring manufacturing method in the third embodiment is different from the first and second embodiments in the arrangement of the thermometer 22 in the step (S30).

  That is, referring to FIG. 9, in step (S30) in the third embodiment, the temperatures at a plurality of locations (here, 4 locations) on rolling surface 11A that is a heating region are measured. More specifically, in the step (S30) of the third embodiment, a plurality of thermometers 22 are arranged at equal intervals along the circumferential direction of the rolling surface 11A of the molded body 11, and positions at equal intervals in the circumferential direction. The temperature of is measured.

  Thereby, since the temperature of several places is measured simultaneously in the circumferential direction of 11 A of rolling surfaces, after confirming that homogeneous heating is implement | achieved in the circumferential direction of 11 A of rolling surfaces, the molded object 11 is rapidly cooled. A quench hardening treatment can be carried out. As a result, according to the method for manufacturing the outer ring of the rolling bearing in the third embodiment, it is possible to achieve more uniform quench hardening in the circumferential direction of the rolling surface 11A.

  In addition, in the said embodiment, although the case where the coil 21 was fixed and the molded object 11 was rotated was demonstrated, the molded object 11 may be fixed and the coil 21 may be rotated in the circumferential direction of the molded object 11, The coil 21 may be relatively rotated along the circumferential direction of the molded body 11 by rotating both the coil 21 and the molded body 11. However, since the coil 21 requires wiring for supplying a current to the coil 21, it is often reasonable to fix the coil 21 as described above.

  Further, in the above embodiment, the case where the outer ring of the double row tapered roller bearing is manufactured as an example of the bearing ring is described. However, the bearing ring to which the present invention is applicable is not limited to this, for example, a radial type rolling bearing. Or a thrust type bearing ring. Here, in the step (S20), for example, when heating the inner ring of the radial type rolling bearing, the coil 21 may be disposed so as to face the rolling surface formed on the outer peripheral side of the molded body. Further, in the step (S20), for example, when heating the bearing ring of the thrust type rolling bearing, the coil 21 may be disposed so as to face the rolling surface formed on the end surface side of the molded body.

  Furthermore, the length of the coil 21 as the induction heating member in the circumferential direction of the molded body 11 can be appropriately determined so as to realize efficient and uniform heating. For example, the length of the region to be heated is 1 / 12, that is, a length such that the central angle with respect to the central axis of the molded body (orbital ring) is 30 °.

Moreover, in order to suppress the variation in the temperature in the circumferential direction, it is preferable to provide a step of holding the molded body in a state where the heating is stopped after the induction heating is completed and before cooling to a temperature equal to or lower than the _MS point. .

(Embodiment 4)
Next, Embodiment 4 in which the rolling bearing manufactured by the method for manufacturing a rolling bearing according to the present invention is used as a bearing for a wind turbine generator (a rolling bearing for a wind turbine generator) will be described.

  Referring to FIG. 10, wind power generator 50 is connected to blade 52 that is a swirl wing, main shaft 51 that is connected to blade 52 at one end so as to include the central axis of blade 52, and the other end of main shaft 51. The speed-up gear 54 is provided. Further, the speed increaser 54 includes an output shaft 55, and the output shaft 55 is connected to the generator 56. The main shaft 51 is rotatably supported around the shaft by a main shaft bearing 3 which is a rolling bearing for a wind power generator. Further, a plurality of main shaft bearings 3 are arranged side by side in the axial direction of the main shaft 51 (two in FIG. 10), and are respectively held by a housing 53. The main shaft bearing 3, the housing 53, the speed increaser 54, and the generator 56 are housed in a nacelle 59 that is a machine room. The main shaft 51 protrudes from the nacelle 59 at one end and is connected to the blade 52.

  Next, the operation of the wind power generator 50 will be described. Referring to FIG. 10, when the blade 52 rotates in the circumferential direction by receiving the wind force, the main shaft 51 connected to the blade 52 rotates around the shaft while being supported by the main shaft bearing 3 with respect to the housing 53. The rotation of the main shaft 51 is transmitted to the speed increaser 54 to be accelerated, and converted into rotation around the output shaft 55. Then, the rotation of the output shaft 55 is transmitted to the generator 56, and an electromotive force is generated by the electromagnetic induction action to achieve power generation.

  Next, a support structure for the main shaft 51 of the wind turbine generator 50 will be described. Referring to FIG. 11, main shaft bearing 3 as a rolling bearing for wind power generator includes an annular outer ring 31 as a raceway of the rolling bearing for wind power generator, and wind power generation disposed on the inner peripheral side of outer ring 31. An annular inner ring 32 as a bearing ring of the rolling bearing for the device, and a plurality of rollers 33 disposed between the outer ring 31 and the inner ring 32 and held by an annular retainer 34 are provided. An outer ring rolling surface 31 </ b> A is formed on the inner circumferential surface of the outer ring 31, and an inner ring rolling surface 32 </ b> A is formed on the outer circumferential surface of the inner ring 32. And the outer ring | wheel 31 and the inner ring | wheel 32 are arrange | positioned so that the inner ring | wheel rolling surface 32A may oppose the outer ring | wheel rolling surface 31A. Further, the plurality of rollers 33 are in contact with the outer ring rolling surface 31A and the inner ring rolling surface 32A along the two inner ring rolling surfaces 32A at the roller contact surface 33A and are held by the cage 34. By being arranged at a predetermined pitch in the circumferential direction, it is rotatably held on a double row (two rows) annular track. The outer ring 31 is formed with a through hole 31E that penetrates the outer ring 31 in the radial direction. Lubricant can be supplied to the space between the outer ring 31 and the inner ring 32 through the through hole 31E. With the above configuration, the outer ring 31 and the inner ring 32 of the main shaft bearing 3 are rotatable relative to each other.

  On the other hand, the main shaft 51 connected to the blade 52 passes through the inner ring 32 of the main shaft bearing 3 and comes into contact with the fitting surface 32F, which is the inner peripheral surface of the inner ring, on the outer peripheral surface 51A. Is fixed. Further, the outer ring 31 of the main shaft bearing 3 is fitted into an inner wall 53 </ b> A of a through hole formed in the housing 53 so as to come into contact with a fitting surface 31 </ b> F that is an outer peripheral surface, and is fixed to the housing 53. With the above configuration, the main shaft 51 connected to the blade 52 can rotate about the shaft relative to the outer ring 31 and the housing 53 integrally with the inner ring 32.

  Further, flange portions 32E that protrude toward the outer ring 31 are formed at both ends in the width direction of the inner ring rolling surface 32A. Thereby, a load in the axial direction (axial direction) of the main shaft 51 generated when the blade 52 receives wind is supported. The outer ring rolling surface 31A has a spherical shape. Therefore, the outer ring 31 and the inner ring 32 can make an angle with each other around the center of the spherical surface in a cross section perpendicular to the rolling direction of the rollers 33. That is, the main shaft bearing 3 is a double-row self-aligning roller bearing. As a result, even when the main shaft 51 is bent due to the wind received by the blade 52, the housing 53 can stably and rotatably hold the main shaft 51 via the main shaft bearing 3.

  And the outer ring | wheel 31 and the inner ring | wheel 32 as a bearing ring of the rolling bearing for wind power generators in Embodiment 4 are manufactured by the manufacturing method similar to the outer ring | wheel 11 and the inner ring | wheel 12 in above-mentioned Embodiment 1, and have the same structure. Have. That is, the outer ring 31 and the inner ring 32 have an inner diameter of 1000 mm or more, like the outer ring 11 and the inner ring 12. Moreover, the outer ring | wheel 31 and the inner ring | wheel 32 are rolling surface hardened layers 31G and 32G formed over the perimeter along rolling surface 31A, 32A so that rolling surface 31A, 32A may be included, and another member. Fitting surface hardened layers 31H and 32H formed along the fitting surfaces 31F and 32F so as to include a fitting surface 31F that fits into the housing 53 or a fitting surface 32F that fits into the main shaft 51 that is another member. And non-hardened regions 31I and 32I formed between the rolling surface hardened layers 31G and 32G and the mating surface hardened layers 31H and 32H. And the thickness of the fitting surface hardened layers 31H and 32H is smaller than the thickness of the rolling surface hardened layers 31G and 32G. As a result, the outer ring 31 and the inner ring 32 are raceway rings of large-sized rolling bearings in which rolling surface hardened layers 31G and 32G are formed along the rolling surfaces 31A and 32A, and durability is improved. The main shaft bearing 3 (self-aligning roller bearing) provided with the outer ring 31 and the inner ring 32 is a large-sized rolling bearing with excellent durability.

  The bearing ring and rolling bearing of the present invention are suitable for a bearing ring of a large-sized rolling bearing and a rolling bearing provided with the bearing ring. In the said Embodiment 4, although the bearing for wind power generators was demonstrated as an example of a large sized rolling bearing, the application to another large sized rolling bearing is also possible. More specifically, for example, the present invention is applied to a rolling bearing for a CT scanner that rotatably supports a rotating mount on which an X-ray irradiation unit of a CT scanner is installed with respect to a fixed mount that is arranged so as to face the rotating mount. The bearing ring and the rolling bearing of the invention can be preferably applied. Further, the bearing ring and rolling bearing of the present invention can be applied to any form of bearing ring and rolling bearing such as a deep groove ball bearing, an angular ball bearing, a cylindrical roller bearing, a tapered roller bearing, a self-aligning roller bearing, and a thrust ball bearing. Applicable. Further, in the above embodiment, the case where both the inner ring and the outer ring are race rings manufactured by the method for manufacturing a race ring of the present invention has been described. However, the rolling bearing of the present invention is not limited to this, and the inner ring and One of the outer rings may be manufactured by the track ring manufacturing method of the present invention.

  The embodiment disclosed this time is to be considered as illustrative in all points 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.

  The method for manufacturing a bearing ring and the method for manufacturing a rolling bearing according to the present invention includes a method for manufacturing a bearing ring and a rolling method in which a hardened hardened layer is required to be uniformly formed along the rolling surface by induction hardening. The present invention can be applied particularly advantageously to a method for manufacturing a bearing.

  DESCRIPTION OF SYMBOLS 1 Double row tapered roller bearing, 3 Main shaft bearing, 11 Outer ring (molded body), 11A Outer ring rolling surface, 11B, 12B fitting surface, 11C, 12C Rolling surface hardened layer (heating region), 11D, 12D fitting Mating surface hardened layer, 11E, 12E non-hardened region, 12 inner ring, 12A inner ring rolling surface, 13 rollers, 14 cage, 21, 23 coil, 22 thermometer, 24 coolant injection unit, 25 moving quenching device, 31 outer ring, 31A outer ring rolling surface, 31E through hole, 31F, 32F mating surface, 31G, 32G rolling surface hardened layer, 31H, 32H mating surface hardened layer, 31I, 32I non-hardened region, 32 inner ring, 32A inner ring rolling surface, 32E buttocks, 33 rollers, 33A roller contact surface, 34 cage, 50 wind power generator, 51 main shaft, 51A outer peripheral surface, 52 blade, 53 housing, 3A inner wall 54 gearbox, 55 output shaft, 56 power generator 59 nacelle.

Claims (12)

A method of manufacturing a bearing ring for a rolling bearing,
Preparing a formed body made of steel;
An induction heating member that is arranged so as to face a part of an annular region that is to be a rolling surface of the raceway in the molded body and that is relatively heated along a circumferential direction of the annular region. To form an annular heating region heated to a temperature of A ₁ point or more in the molded body,
By simultaneously cooling the entire heating region to a temperature below M _S point, forming a rolling surface hardening layer over the entire circumference along the annular region,
Another induction heating member that is arranged so as to face a part of the region to be the fitting surface of the raceway in the molded body and that induction heats the molded body is arranged around the region to be the fitting surface. The fitting surface hardened layer is formed by cooling the region heated by the other induction heating member by the cooling member that moves relative to the direction and moves the other induction heating member. A method of manufacturing a bearing ring, comprising: a process.   The track ring manufacturing method according to claim 1, further comprising a step of performing a normalizing process on the molded body prior to the step of forming the heating region.   The track ring according to claim 2, wherein in the step of performing the normalizing process, shot blasting is performed while the molded body is cooled by spraying hard particles together with gas to the molded body. Production method. The method for manufacturing a bearing ring according to claim 1, further comprising a step of performing a tempering process after performing a quenching process on the entire formed body before the step of forming the heating region. The raceway includes a double row rolling surface;
The rolling surface in the step of forming the hardening layer, the heating region of the double row is cooled M _S point below the temperature at the same time, the manufacturing method of the bearing ring according to any one of claims 1-4 . The track ring manufacturing according to any one of claims 1 to 5 , wherein in the step of forming the heating region, the induction heating member relatively rotates two or more times along a circumferential direction of the molded body. Method. Wherein in the step of forming the heating region, the induction heating member is a plurality arranged along the circumferential direction of the molded body, method for manufacturing a bearing ring according to any one of claims 1-6. The method for manufacturing a bearing ring according to any one of claims 1 to 7 , wherein in the step of forming the heating region, temperatures at a plurality of locations in the heating region are measured. In the step of preparing the molded body, 0.43% to 0.65% carbon, 0.15% to 0.35% silicon, and 0.60% to 1.10%. Containing steel of the balance iron and impurities, containing manganese by mass% or less, chromium by 0.30 mass% or more and 1.20 mass% or less, and molybdenum by 0.15 mass% or more and 0.75 mass% or less The method for manufacturing a bearing ring according to any one of claims 1 to 8 , wherein the formed body is prepared. In the step of preparing the molded body, 0.43% to 0.65% carbon, 0.15% to 0.35% silicon, and 0.60% to 1.10%. Manganese of less than mass%, chromium of 0.30 mass% or more and 1.20 mass% or less, molybdenum of 0.15 mass% or more and 0.75 mass% or less, and 0.35 mass% or more and 0.75 mass% The manufacturing method of the bearing ring of any one of Claims 1-8 with which the said molded object comprised from the steel which contains the following nickel and consists of remainder iron and an impurity is prepared. A process of preparing a bearing ring;
Preparing a rolling element;
A step of assembling a rolling bearing by combining the raceway and the rolling element,
The bearing ring is manufactured by the manufacturing method of the bearing ring according to any one of claims 1-10, a manufacturing method of the rolling bearing. The rolling bearing according to claim 11 , wherein the rolling bearing is used as a rolling bearing for a wind power generator that rotatably supports a main shaft connected to a blade with respect to a member adjacent to the main shaft in the wind power generator. Production method.

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