JP6178365B2 - Manufacturing method of bearing ring, cylindrical roller bearing and tapered roller bearing - Google Patents

Description

  The present invention relates to a method for manufacturing a bearing ring and a rolling bearing, and more specifically, while suppressing the manufacturing cost of a quenching device, the quench hardened layer is made homogeneous along the rolling surface by induction hardening. The present invention relates to a bearing ring that can be formed and a method of manufacturing a rolling bearing.

  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 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 the annular region to be heated of the race and moves relatively along the region, and is heated. By spraying a coolant such as water immediately after passing through the coil to the region, the region is sequentially hardened and hardened. 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 overlapping 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.

  In the conventional induction hardening of the raceway, the region of the coil that faces the raceway and contributes to the heating of the raceway (induction heating region) has a curved shape corresponding to the shape of the raceway. For this reason, when quenching the races of different sizes and shapes, coils corresponding to the shapes of the races are required, which increases the manufacturing cost of the quenching device.

  The present invention has been made in order to solve the above-described problems, and its purpose is to suppress the production cost of the quenching apparatus and to completely cure the quench hardened layer along the rolling surface by induction quenching. It is an object of the present invention to provide a method for manufacturing a bearing ring and a rolling bearing that can be formed uniformly over the circumference.

The method for manufacturing a bearing ring according to the present invention is a method for manufacturing either a cylindrical roller bearing or a tapered roller 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 or more points A on the formed body by relatively rotating the induction heating coil to be heated along the circumferential direction of the annular region, and the entire heating region A step of simultaneously cooling to a temperature equal to or lower than the _MS point; and a step of holding the molded body in a state where heating is stopped after the step of forming the heating region and before the step of cooling. And in the process of forming a heating area | region, the induction heating coil which has the shape where the area | region (induction heating area | region) which faces the annular area and contributes to the heating of an annular area is included in the same plane is used.

In the method for manufacturing a raceway ring according to the present invention, an induction heating coil arranged so as to face a part of an 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 coil 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 race of the present invention, an induction heating coil having a shape in which the induction heating region is included in the same plane is used. Therefore, even when quenching of the race rings having different sizes and shapes, coils corresponding to the shapes of the respective race rings are not necessary, and the manufacturing cost of the quenching apparatus can be reduced. As described above, according to the raceway manufacturing method of the present invention, the hardened hardened layer is uniformly formed along the rolling surface by induction hardening while suppressing the manufacturing cost of the quenching apparatus. be able to.

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.

  Preferably, in the above-described method for manufacturing a bearing ring, in the step of forming the heating region, a plurality of induction heating coils are arranged along the circumferential direction of the molded body. Thereby, the dispersion | variation in the temperature in the circumferential direction of a rolling surface (annular area | region) can be suppressed, and homogeneous quench hardening can be implement | achieved.

  Preferably, in the method of manufacturing the bearing ring, in the step of forming the heating region, the plurality of induction heating coils are arranged at equal intervals along the circumferential direction of the molded body. Thereby, the dispersion | variation in the temperature in the circumferential direction of a rolling surface (annular area | region) can be suppressed, and more homogeneous quench hardening can be implement | achieved.

  Preferably, in the above-described method for manufacturing a race, in the step of forming the heating region, the induction heating coil relatively rotates 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 (annular area | region) can be suppressed, and homogeneous quench hardening can be implement | achieved.

  Preferably, in the method of manufacturing the bearing ring, in the step of forming the heating region, temperatures at a plurality of locations in the heating region are measured. Thereby, after confirming that uniform heating is realized in the circumferential direction of the rolling contact surface, the heating region can be rapidly cooled to perform quench hardening treatment. 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 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 that is manufactured by partially quenching and hardening the region including the rolling surface by induction hardening, it has a hardness that can secure a predetermined strength even in a region that is not hardened (non-hardened region). Need to be. 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.

A method of manufacturing a rolling bearing according to the present invention is a method of manufacturing a cylindrical roller bearing or a tapered roller bearing, a step of preparing a raceway of the cylindrical roller bearing or the tapered roller bearing, a step of preparing a rolling element, A step of assembling a cylindrical roller bearing or a tapered roller bearing by combining the raceway and the rolling element. And the race ring is manufactured and prepared by the method for manufacturing a race ring of the present invention.

  According to the rolling bearing manufacturing method of the present invention, by manufacturing the bearing ring by the above-described manufacturing method of the bearing ring of the present invention, the quench hardened layer is formed by induction hardening while suppressing the manufacturing cost of the quenching device. It is possible to manufacture a rolling bearing having a bearing ring that is uniformly formed over the entire circumference along the rolling surface.

  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 for manufacturing a rolling bearing according to the present invention that can form a hardened hardened layer in a region including the rolling surface of a large-sized bearing ring at low cost is suitable as a method for manufacturing a rolling bearing for a wind power generator. is there.

  As is clear from the above description, according to the method of manufacturing the bearing ring and the rolling bearing of the present invention, the quench hardened layer is formed along the rolling surface by induction hardening while suppressing the manufacturing cost of the quenching device. It is possible to provide a method of manufacturing a bearing ring and a rolling bearing that can be formed uniformly over the entire circumference.

It is a flowchart which shows the outline of the manufacturing method of the bearing ring and rolling bearing of a rolling bearing. It is the schematic for demonstrating a hardening hardening process. It is a schematic sectional drawing which shows the cross section along line segment III-III 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, as a method for manufacturing the raceway, a method for manufacturing the inner ring will be mainly described, but the outer ring can be manufactured in the same manner.

  Referring to FIG. 1, in the inner ring manufacturing method according to the present embodiment, a molded body preparation step is first performed as a step (S <b> 10). 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 inner ring is produced. More specifically, a molded body corresponding to the shape of the inner ring having an inner diameter of 1000 mm or more is produced. Here, when the inner ring to be manufactured is particularly large and high hardenability is required for the steel, a steel material in which 0.35 mass% or more and 0.75 mass% or less of nickel is added in addition to the above alloy components is adopted. 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 quench hardening process is implemented. This quench hardening process includes an induction heating process performed as the process (S30) and a cooling process performed as the process (S40). In step (S30), with reference to FIG. 2 and FIG. 3, coil 21 as an induction heating coil is a part of rolling surface 11 (annular region) that is a surface on which rolling element should roll in molded body 10. It is arranged to face. Here, in the coil 21, the induction heating area 21A that faces the rolling surface 11 and contributes to the heating of the rolling surface 11 is included in the same plane as shown in FIGS. That is, the area | region which opposes the rolling surface 11 in the coil 21 has the planar shape contained in the same plane.

Next, the molded body 10 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). Thereby, the surface layer region including the rolling surface 11 of the formed body 10 is induction-heated to a temperature of A ₁ point or more, and an annular heating region 11A along the rolling surface 11 is formed. At this time, the temperature of the surface of the rolling surface 11 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 10 including the heating region 11A formed in the step (S30), so that the entire heating region 11A is M. Simultaneous cooling to a temperature below the _S point. Thereby, the heating region 11A is transformed into martensite, and the region including the rolling surface 11 is cured. By the above procedure, induction hardening is performed and the quench hardening process is completed.

Next, a tempering step is performed as a step (S50). In this step (S50), the molded body 10 that has been quenched and hardened in steps (S30) and (S40) is charged into, for example, a furnace, heated to a temperature of A ₁ point or less, and held for a predetermined time. Thus, a tempering process is performed.

  Next, a finishing step is performed as a step (S60). In this step (S60), for example, a finishing process such as a polishing process is performed on the rolling surface 11. With the above process, the inner ring of the rolling bearing is completed, and the production of the inner ring in the present embodiment is completed. As a result, referring to FIG. 2 and FIG. 3, an inner ring 10 having an inner diameter of 1000 mm or more and having a hardened hardened layer formed uniformly along the rolling surface 11 along the rolling surface 11 by induction hardening is completed. .

  Furthermore, an assembly process is performed as a process (S70). In this step (S70), the inner ring 10 produced as described above and the outer ring produced in the same manner as the inner ring 10 are combined with separately prepared rolling elements, cages, etc. The main shaft bearing 3 of the wind turbine generator shown in FIG. 7 is assembled. With the above procedure, the rolling bearing manufacturing method in the present embodiment is completed.

In the present embodiment, in the step (S30), the coil 21 disposed so as to face a part of the rolling surface of the molded body 10 is relatively rotated along the circumferential direction so that the molded body 10 is A heating region 11A is formed. Therefore, it is possible to employ a small coil 21 with respect to the outer shape of the molded body 10, and the manufacturing cost of the quenching apparatus can be suppressed even when the large molded body 10 is quenched and hardened. . In the present embodiment, the entire heating area 11A is simultaneously cooled to a temperature not higher than the _MS point. Therefore, it becomes possible to form an annular quenching and hardening region that is homogeneous in the circumferential direction, and the residual stress is prevented from concentrating on a part of the region.

  Further, in the present embodiment, in step (S30), coil 21 having a shape in which the induction heating region is included in the same plane is used. Therefore, even when quenching the molded bodies (inner rings) 10 having different sizes and shapes, coils corresponding to the shapes of the respective molded bodies (inner rings) are not necessary, and the manufacturing cost of the quenching apparatus can be reduced. it can. As described above, according to the inner ring manufacturing method of the present embodiment, the hardened hardened layer is uniformly formed along the rolling surface by induction hardening while suppressing the manufacturing cost of the quenching apparatus. can do.

  In addition, according to the method for manufacturing a rolling bearing in the present embodiment, a rolling bearing including a bearing ring in which a hardened hardened layer is uniformly formed over the entire circumference along the rolling surface by induction hardening is manufactured at low cost. can do.

  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 10 is cooled by spraying hard particles together with gas on the molded body 10. 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 10 is removed, and the characteristics of the inner ring 10 due to 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.

  Further, in the step (S30), the molded body 10 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 10 may be rotated a plurality of times. preferable. That is, it is preferable that the coil 21 as the induction heating coil relatively rotate two or more times along the circumferential direction of the rolling surface 11 of the molded body 10.

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

That is, with reference to FIG. 4, in the step (S30) in the second embodiment, a plurality (six in this case) of coils 21 are arranged along the rolling surface 11 formed on the outer peripheral surface of the molded body 10. Is done. As in the case of the first embodiment, the molded body 10 is rotated in the direction of the arrow α, and a high frequency current is supplied to the coil 21 from a power source (not shown). Thereby, the surface layer region including the rolling surface 11 of the formed body 10 is induction-heated to a temperature of A ₁ point or more, and an annular heating region 11A along the rolling surface 11 is formed.

  As described above, by arranging a plurality of the coils 21 along the circumferential direction of the molded body 10, the method for manufacturing the inner ring of the rolling bearing according to the second embodiment suppresses variation in temperature in the circumferential direction and is uniform. This is a method for manufacturing a raceway ring that can achieve 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 10.

(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. 5, in step (S30) in the third embodiment, the temperatures at a plurality of locations (here, 4 locations) of rolling surface 11 that is the 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 11 of the molded body 10.

  Thereby, since the temperature of several places is measured simultaneously in the circumferential direction of the rolling surface 11, after confirming that the uniform heating is implement | achieved in the circumferential direction of the rolling surface 11, the molded object 10 is rapidly cooled. A quench hardening treatment can be carried out. As a result, according to the method for manufacturing the inner ring of the rolling bearing in the third embodiment, more uniform quench hardening in the circumferential direction of the rolling surface 11 can be realized.

  In addition, in the said embodiment, although the case where the coil 21 was fixed and the molded object 10 was rotated was demonstrated, the molded object 10 may be fixed and the coil 21 may be rotated in the circumferential direction of the molded object 10, The coil 21 may be relatively rotated along the circumferential direction of the molded body 10 by rotating both the coil 21 and the molded body 10. 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 inner ring of the radial type rolling bearing is manufactured as an example of the bearing ring has been described. However, the bearing ring to which the present invention can be applied is not limited to this, for example, a radial type rolling bearing. It may be an outer ring or a bearing ring of a thrust type bearing. Here, in the step (S30), for example, when the outer ring of the radial type rolling bearing is heated, the coil 21 may be disposed so as to face the rolling surface formed on the inner peripheral side of the molded body. Further, in the step (S30), 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.

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. 6, wind turbine generator 50 is connected to blade 52 that is a swirl blade, 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 (two in FIG. 6) are arranged in the axial direction of the main shaft 51, 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. 6, when the blade 52 rotates in the circumferential direction by receiving 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. 7, main shaft bearing 3 as a rolling bearing for wind power generator includes an annular outer ring 31 as a raceway of the wind bearing for rolling 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 of the bearing ring described in the said Embodiment 1-3, for example. The outer ring 31 and the inner ring 32 are raceways of a rolling bearing for a wind power generator having an inner diameter of 1000 mm or more. A hardened and hardened layer is uniformly formed on the outer ring 31 and the inner ring 32 over the entire circumference along the outer ring rolling surface 31A and the inner ring rolling surface 32A by induction hardening. That is, the outer ring 31 and the inner ring 32 have an inner diameter of 1000 mm or more, are formed by induction hardening, and have a hardened hardening layer having an annular shape with a uniform depth along the circumferential direction. The surface of the hardened layer is an outer ring rolling surface 31A and an inner ring rolling surface 32A, respectively. As a result, the outer ring 31 and the inner ring 32 are large-sized races in which a quench-hardened layer is uniformly formed along the rolling surface by induction hardening while suppressing the cost of heat treatment. This is a bearing ring that constitutes a bearing for a wind turbine generator that can be used even in harsh environments.

  In addition, the manufacturing method of the bearing ring and rolling bearing of this invention is suitable for manufacture of the bearing ring and large-sized rolling bearing of a large-sized rolling bearing. 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. Specifically, for example, a bearing ring of a rolling bearing for 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 arranged to face the rotating mount. And the manufacturing method of the bearing ring and rolling bearing of this invention can be applied suitably for manufacture of the rolling bearing for CT scanners. The method of manufacturing the bearing ring and rolling bearing according to the present invention includes a bearing ring of an arbitrary 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. And applicable to rolling bearings.

  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 manufacturing method of the bearing ring and the rolling bearing of the present invention is required to uniformly form a hardened hardened layer along the rolling surface by induction hardening while suppressing the manufacturing cost of the quenching apparatus. It can be applied particularly advantageously to the production of bearing rings and rolling bearings.

  3 Bearing for main shaft, 10 Molded body (inner ring), 11 Rolling surface, 11A Heating region, 21 Coil, 21A Induction heating region, 22 Thermometer, 31 Outer ring, 31A Outer ring rolling surface, 31E Through hole, 31F Fitting surface , 32 inner ring, 32A inner ring rolling surface, 32E collar part, 32F fitting surface, 33 rollers, 33A roller contact surface, 34 cage, 50 wind power generator, 51 main shaft, 51A outer peripheral surface, 52 blade, 53 housing, 53A Inner wall, 54 gearbox, 55 output shaft, 56 generator, 59 nacelle.

Claims (14)

A method of manufacturing a raceway ring of either a cylindrical roller bearing or a tapered roller bearing,
Preparing a formed body made of steel;
An induction heating coil that is arranged so as to face a part of the annular region to be a rolling surface of the race in the molded body, and that induction-heats the molded body relative to each other along the 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,
Simultaneously cooling the entire heating area to a temperature below the _MS point;
After the step of forming the heating region, and before the step of cooling, a step of holding the molded body in a state where heating is stopped in order to suppress temperature variation in the circumferential direction of the annular region. Prepared,
In the step of forming the heating region, a method of manufacturing a bearing ring, wherein the induction heating coil having a shape that faces the annular region and contributes to heating of the annular region is included in the same plane.   The track ring manufacturing method according to claim 1, wherein in the step of forming the heating region, a plurality of the induction heating coils are arranged along a circumferential direction of the molded body.   The track ring manufacturing method according to claim 2, wherein, in the step of forming the heating region, the plurality of induction heating coils are arranged at equal intervals along a circumferential direction of the molded body.   The track ring manufacturing according to any one of claims 1 to 3, wherein, in the step of forming the heating region, the induction heating coil rotates relatively two or more times along a circumferential direction of the molded body. Method.   The method for manufacturing a bearing ring according to any one of claims 1 to 4, 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 manufacturing method of the bearing ring of any one of Claims 1-5 by which the said molded object comprised 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 1-5 by which the said molded object comprised from the steel which contains the following nickel and consists of remainder iron and an impurity is prepared.   The method for manufacturing a bearing ring according to any one of claims 1 to 7, further comprising a step of performing a normalizing process on the molded body before the step of forming the heating region.   The track ring according to claim 8, 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.   8. The method 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. 9. A method of manufacturing a bearing ring. Preparing a ring of cylindrical roller bearings;
Preparing a rolling element;
A step of assembling a cylindrical roller bearing by combining the raceway and the rolling element,
The said bearing ring is a manufacturing method of a cylindrical roller bearing manufactured by the manufacturing method of the bearing ring of any one of Claims 1-10.   The cylindrical roller bearing according to claim 11, wherein the cylindrical roller bearing is used as a cylindrical roller 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. A method of manufacturing a roller bearing. A step of preparing a tapered roller bearing raceway,
Preparing a rolling element;
A step of assembling a tapered roller bearing by combining the raceway and the rolling element,
The said bearing ring is a manufacturing method of the tapered roller bearing manufactured by the manufacturing method of the bearing ring of any one of Claims 1-10.   The tapered roller bearing according to claim 13, wherein the tapered roller bearing is used as a tapered roller 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. A method of manufacturing a roller bearing.

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