JP2017082943A - Process of manufacture of bearing ring and process of manufacture of double row conical roller bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a double row conical roller bearing of which manufacturing cost is restricted.SOLUTION: This invention relates to a process of manufacture of a bearing ring of a double row conical roller bearing comprising the steps for: preparing a compact; forming a heating region; holding the compact in a state where its heating is stopped; and cooling it. At the step for preparing the compact, the compact is constituted of steel to prepare a compact in which an annular groove 19 that is to become a rolling surface 11 of the bearing ring at its bottom surface is formed at an outer peripheral surface. At the step for forming the heating region, the compact is heated through induction heating to include the bottom surface of the groove 19 and the heating region heated up to a temperature of a point Ais formed. At the cooling step, the entire heating region is simultaneously cooled to a temperature of a point Mor less. The step for holding the compact in a state in which the heating is stopped is executed before the cooling step after the step for forming the heating region is carried out. At the holding step, a disturbance in temperature in a peripheral direction in the heating region is restricted to a value of 20°C or less.SELECTED DRAWING: Figure 9

Description

  The present invention relates to a method for manufacturing a raceway ring and a method for manufacturing a double row tapered roller bearing.

  For a wind turbine generator bearing, for example, a main bearing that supports a shaft that transmits the rotational power of a blade, in addition to a load component caused by the weight of the blade and the rotor, a load component caused by a wind load also acts. That is, an axial load acts on the bearing in addition to the radial load. For this reason, it has been conventionally proposed to use a double-row tapered roller bearing as a bearing for a wind power generator (see, for example, JP-T-2008-546948).

Special table 2008-546948

  As disclosed in the above special table 2008-546948, a plurality of bolt holes are formed in the outer ring of the double row tapered roller bearing applied to the wind power generator, and the bolt holes are inserted into the outer rings. It is fixed to surrounding parts such as a wind power generator housing with bolts. Similarly, a bolt hole may be formed on the inner ring of the double row tapered roller bearing.

  For the outer ring and inner ring of such a double-row tapered roller bearing, a process of carburizing and quenching using carburized steel is employed to obtain the required hardness. This is due to the following reasons.

  That is, as described above, the plurality of bolt holes formed in the outer ring or the like requires high positional accuracy in order to accurately fix the double row tapered roller bearing to the surrounding parts. Therefore, if the bolt hole is formed after the heat treatment for the outer ring or the like is completed, there is no need to consider the deformation of the outer ring accompanying the heat treatment as in the case of forming the bolt hole before the heat treatment, and the work efficiency is also improved. Can be made. On the other hand, if the hardness of the outer ring or the like is increased by heat treatment, the machinability is lowered and machining becomes difficult. That is, when bearing steel is used as a material for an outer ring or the like and general quenching is performed as a heat treatment, there is a problem that it is difficult to process the above-described bolt hole.

  Therefore, if carburized steel is used as a material for the outer ring or the like as described above, and carburizing and quenching is performed on the region where the bolt holes are to be formed, the vibration-proofing treatment is not performed. While it is possible to increase the hardness of the region, since the increase of the hardness is prevented in the region subjected to the carburizing treatment, the process of forming the bolt hole after the carburizing and quenching can be easily performed.

  However, when the carburizing heat treatment as described above is performed, the number of steps such as performing a carburizing prevention treatment is increased as compared with a general quenching process, and the processing time of the heat treatment itself is longer than a general overall quenching process. There was a problem that the manufacturing cost increased.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a double-row tapered roller bearing with reduced manufacturing costs.

A method of manufacturing a bearing ring according to the present disclosure is a method of manufacturing a bearing ring of a double-row tapered roller bearing, in which a step of preparing a molded body, a step of forming a heating region, and heating of the molded body are stopped. A step of maintaining the state and a step of cooling. In the step of preparing the formed body, a formed body is prepared, which is made of steel and has an annular groove formed on the outer peripheral surface, the bottom surface of which should be the rolling surface of the race. In the step of forming the heating region, the heating region including the bottom surface of the groove and heated to a temperature of A ₁ point or higher is formed by induction heating of the molded body. In the cooling step, the entire heating region is simultaneously cooled to a temperature below the M _s point. The step of holding the molded body in a state where heating is stopped is performed after the step of forming the heating region and before the step of cooling. In the holding step, the temperature variation in the circumferential direction in the heating region is suppressed to 20 ° C. or less.

  A method of manufacturing a double-row tapered roller bearing according to the present disclosure includes a step of preparing a bearing ring, a step of preparing a tapered roller, and a step of assembling a double-row tapered roller bearing by combining the bearing ring place. . The bearing ring is manufactured by the above-described manufacturing method of the bearing ring.

  According to the above, it is possible to obtain a double-row tapered roller bearing provided with a raceway having sufficient characteristics without causing an increase in manufacturing cost.

It is a schematic diagram of the double row tapered roller bearing according to the first embodiment. FIG. 2 is a partial cross-sectional schematic view taken along line II-II shown in FIG. 1. It is a schematic diagram for demonstrating the wind power generator to which the double row tapered roller bearing shown in FIG. 1 is applied. It is a flowchart which shows the outline of the manufacturing method of the race of the double row tapered roller bearing shown in FIG. 1, and a double row tapered roller bearing. It is a cross-sectional schematic diagram of a molded object. It is a partial cross section schematic diagram of a molded object. It is a schematic diagram for demonstrating a hardening hardening process. It is a cross-sectional schematic diagram in line segment VIII-VIII of FIG. It is a schematic diagram for demonstrating a finishing process. FIG. 10 is a schematic diagram for explaining a first example of a quench hardening process in the second embodiment. FIG. 6 is a schematic diagram for explaining a second example of a quench hardening process in the second embodiment. FIG. 6 is a schematic diagram for explaining a quench hardening process in a third embodiment. It is a partial cross-section schematic diagram of the bearing ring as a comparative example.

  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)
<Configuration of double row tapered roller bearing>
The configuration of the double row tapered roller bearing according to the first embodiment will be described with reference to FIGS. 1 and 2.

  The double-row tapered roller bearing shown in FIG. 1 and FIG. 2 includes an outer ring 2 that is a race ring having an annular shape, and an inner ring 5 that is disposed on the inner peripheral side of the outer ring 2 and is a race ring having an annular shape. A plurality of rollers 6 as rolling elements and a cage 7 that prescribes the arrangement of the plurality of rollers 6 are mainly provided. Bolt holes 8 are formed in the outer ring 2. The bolt hole 8 is formed to extend along the thrust direction of the double row tapered roller bearing. The outer ring 2 is formed with two rolling surfaces on the inner peripheral surface thereof. The two rolling surfaces include a hardened region 15. Further, the portion other than the portion where the hardened region 15 is formed in the outer ring 2 is a non-hardened region 18 having a lower hardness than the hardened region 15.

  The inner ring 5 includes two inner ring members 3 a and 3 b and an inner ring spacer 4. The two inner ring members 3a and 3b each have an annular shape. The inner ring spacer 4 has an annular shape and is disposed between the inner ring members 3a and 3b. The inner ring spacer 4 may not be provided. In each of the inner ring members 3a and 3b, a groove 19 having a bottom surface serving as a rolling surface is formed on the outer peripheral surface 16 facing the outer ring 2. That is, the inner ring 5 is formed with two rows of grooves 19. From a different viewpoint, the outer peripheral surface 16 means a surface portion extending along the central axis of the roller 6 in the inner ring members 3a and 3b. The roller 6 is disposed inside the groove 19 so as to be in contact with the rolling surface of the inner ring 5 and is in contact with the outer ring 2. The roller 6 is a conical roller. On the outer peripheral surface 16 of the inner ring 5, a region adjacent to the groove 19 is disposed at a position where the hardened region 15 extends from the inner peripheral surface of the groove 19 to the region, and at a position farther from the groove 19 than the hardened region 15. And a non-cured region 18 having a lower hardness than the cured region 15. The region adjacent to the groove 19 on the outer peripheral surface 16 of the inner ring 5 shown in FIG. 2 is a region that sandwiches the groove 19 in the direction along the central axis 25 of the inner ring 5 and extends along the central axis of the roller 6. is there. From a different point of view, the outer peripheral surface 16 of the inner ring 5 is adjacent to the annular groove 19 and has a hardened region 15 formed along the groove 19. From a different point of view, the boundary 17 between the hardened region 15 and the non-hardened region 18 is annularly arranged along the groove 19. The hardened region 15 is formed so as to extend from the bottom and side surfaces of the groove 19 to the outer peripheral surface 16.

  Further, an angle θ formed by the bottom surface of the groove 19 serving as a rolling surface with the central axis 25 of the inner ring 5 is 40 ° or more and 50 ° or less. Further, the angle θ may be 45 °.

<Effects of double row tapered roller bearing>
In the double-row tapered roller bearing 1 shown in FIGS. 1 and 2, the outer peripheral surface 16 of the inner ring 5 includes the non-cured region 18, so that machining such as drilling can be easily performed on the non-cured region 18. It can be carried out. Moreover, since the outer ring | wheel 2 similarly has the non-hardening area | region 18, after performing the heat processing which forms the hardening area | region 15, the hole 8 for bolts can be formed easily.

  In the double row tapered roller bearing 1, the angle θ between the bottom surface of the groove 19 that is a rolling surface and the central shaft 25 of the inner ring 5 is 40 ° or more and 50 ° or less, and therefore only the double row tapered roller bearing 1. A large working point distance can be obtained. For this reason, by applying the double-row tapered roller bearing 1 as a main shaft bearing of a wind power generator, a plurality of cylindrical roller bearings are applied as main shaft bearings. The size of the bearing portion can be reduced.

<Configuration of wind power generator using double row tapered roller bearing>
With reference to FIG. 3, the structure of the wind power generator to which the double-row tapered roller bearing shown in FIG. 1 is applied will be described.

  With reference to FIG. 3, the wind turbine generator 10 mainly includes a main shaft 22, a blade 30, a speed increaser 40, a generator 50, and a main bearing 60. The speed increaser 40, the generator 50 and the main bearing 60 are stored in the nacelle 90. The nacelle 90 is supported by the tower 100. That is, the nacelle 90 is provided in the upper end part of the tower 100 of a wind power generator.

  A plurality of blades 30 are attached to the rotor head 20 connected to the tip of the main shaft 22. The main shaft 22 is supported inside the nacelle 90. The rotation of the main shaft 22 is transmitted to the generator 50 via the speed increaser 40.

  The main shaft 22 enters the nacelle 90 from the rotor head 20 and is connected to the input shaft of the gearbox 40. The main shaft 22 is rotatably supported by a main bearing 60. The main shaft 22 transmits the rotational torque generated by the blade 30 receiving wind force to the input shaft of the speed increaser 40. The blade 30 converts wind force into rotational torque and transmits it to the main shaft 22.

  The main bearing 60 is fixed in the nacelle 90 and rotatably supports the main shaft 22. The main bearing 60 is constituted by the double row tapered roller bearing 1 shown in FIGS. 1 and 2. Further, the double row tapered roller bearing 1 shown in FIGS. 1 and 2 used as the main bearing 60 is fixed to the nacelle 90 by a bolt inserted into the bolt hole 8 of the outer ring 2 shown in FIG.

  The speed increaser 40 is provided between the main shaft 22 and the generator 50, and increases the rotational speed of the main shaft 22 to output to the generator 50. As an example, the speed increaser 40 is configured by a gear speed increasing mechanism including a planetary gear, an intermediate shaft, a high speed shaft, and the like. The generator 50 is connected to the output shaft 61 of the speed increaser 40, and generates power by the rotational torque received from the speed increaser 40. The generator 50 is constituted by, for example, an induction generator.

  The wind power generator is configured to be able to perform a yaw motion that rotates the nacelle 90 in accordance with the wind direction with respect to the tower 100 fixed on the ground. Preferably, the nacelle 90 is rotated so that the blade 30 side is located on the windward side.

  Further, the wind power generator 10 may be configured to obtain an appropriate rotation by changing the angle (hereinafter referred to as pitch) of the blade 30 with respect to the wind direction according to the strength of the wind force. Similarly, when starting and stopping the wind turbine, the blade pitch may be controlled. Further, each blade 30 may be controlled to swing several degrees even during one rotation of the main shaft 22. In this way, the amount of energy that can be obtained from the wind can be adjusted. For example, in a strong wind or the like, the wind receiving surface (also referred to as a blade surface or a blade surface) of the blade is made parallel to the wind direction in order to suppress the rotation of the windmill.

<Production method of double-row tapered roller bearing raceway and double-row tapered roller bearing>
With reference to FIGS. 4 to 9, the raceway of the double row tapered roller bearing and the method for manufacturing the double row tapered roller bearing will be described. In addition, as a manufacturing method of a bearing ring, the manufacturing method of the inner ring member 3a (see FIG. 2) will be mainly described. However, the inner ring member 3b (see FIG. 2) and the outer ring 2 can be similarly manufactured.

  Referring to FIG. 4, 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 standards S53C, SUP13, SCM445, SAE standard 8660H and the like.

  As shown in FIGS. 5 and 6, the compact is made of steel, and an annular groove 19 whose bottom surface is to be the rolling surface 11 of the race is formed on the outer peripheral surface. Further, in the molded body, the region adjacent to the groove 19 includes surplus portions 12 and 13 that extend outward from the position indicated by the dotted line 14 that should be the outer peripheral surface of the raceway ring (inner ring member 3b). Here, the thickness of the surplus portion 12 in the direction along the central axis of the molded body can be set to, for example, 1 mm or more and 5 mm or less. Moreover, the thickness of the surplus part 13 in the radial direction perpendicular to the central axis of the molded body can be set to, for example, 1 mm or more and 5 mm or less.

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, referring to FIG. 4, a quench hardening process is performed. This quench hardening process includes an induction heating process performed as a process (S30), a heating stop holding process performed as a process (S35), and a cooling process performed as a process (S40). In the step (S30), referring to FIG. 7 and FIG. 8, the coil 121 as the induction heating coil is formed on a part of the rolling surface 11 (annular region) that is a surface on which the rolling element should roll in the molded body. Arranged to face. Here, the induction heating region 121A, which is a region that faces the rolling surface 11 and contributes to the heating of the rolling surface 11 in the coil 121, is included in the same plane as shown in FIGS. That is, the area | region which opposes the rolling surface 11 in the coil 121 has the planar shape contained in the same plane.

Next, the compact is rotated around the central axis, specifically in the direction of the arrow α, and a high frequency current is supplied to the coil 121 from a power source (not shown). Thereby, the surface layer region including the rolling surface 11 of the formed body is induction-heated to a temperature of A ₁ point or more, and an annular heating region 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 122 such as a radiation thermometer. Specific conditions for induction hardening can be appropriately set in consideration of conditions such as the size, thickness, material, and power source capacity of the race (molded body). Specifically, for example with reference to FIG. 3, if the outer _{d 1} is 2000 mm, the inner diameter _{d 2} is 1860Mm, width t is induction hardening the rolling surface 11 of the molded body of 100 mm, the rotational speed of the molded body 30 rpm, the frequency of the power supply can be 3 kHz, and the total heating value by induction heating can be 250 kW.

Next, as a step (S35), the molded body in which the heating region is formed in the step (S30) is held in a state where heating is stopped. The step (S35) is performed after the induction heating is completed and before cooling to a temperature equal to or lower than the M _S point in order to suppress the temperature variation in the circumferential direction. More specifically, under the shape of the molded body and the heating conditions, for example, by maintaining the state where the heating is stopped for 3 seconds after the heating is completed, the temperature variation in the circumferential direction on the surface of the heated region is changed. It can suppress to about 20 degrees C or less.

Next, in the step (S40), for example, water as a cooling liquid is sprayed on the entire formed body including the heating region formed in the step (S30), so that the entire heating region is equal to or lower than the _MS point. At the same time to be cooled. Thereby, a heating area | region transforms into a martensite and the area | region containing the rolling surface 11 hardens | cures. 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 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, the tempering process is performed.

  Next, a finishing step is performed as a step (S60). In this step (S60), the shape of the inner ring member 3a is adjusted by removing the surplus portions 12 and 13 of the molded body as shown in FIG. 9, and other necessary processing, for example, polishing processing for the rolling surface 11 is performed. Finishing processing such as is carried out. By the above process, the inner ring member 3a constituting the inner ring of the double row tapered roller bearing is completed. The inner ring member 3a has an inner diameter of 1000 mm or more, and a hardened and hardened layer is uniformly formed along the entire rolling surface 11 by induction hardening.

  Further, the inner ring member 3a is removed from the groove 19 on the outer peripheral surface 16 of the inner ring member 3a by removing the surplus portions 12 and 13 after heat treatment as described above (in FIG. 9, from the groove 19 on the outer peripheral surface 16). The hardened region 15 and the non-hardened region 18 are exposed in a region located near the center axis of the inner ring member 3a. Therefore, by detecting that the hardened region 15 and the non-hardened region 18 are formed on the outer peripheral surface 16 of the inner ring member 3a, the inner ring member 3a uses the raceway manufacturing method according to the present disclosure described above. Whether it is manufactured or not can be easily detected. As a method for detecting that the hardened region 15 and the non-hardened region 18 are formed in a region adjacent to the groove 19 on the outer peripheral surface 16, any conventionally known method such as hardness measurement can be used. Here, the width of the hardened region 15 on the outer peripheral surface 16, that is, the distance from the opening end of the groove 19 to the end of the hardened region 15 can be 2 mm or more and 10 mm or less. Further, in FIG. 9, both the hardened region 15 and the non-hardened region 18 are formed only in the region located near the central axis of the inner ring member 3 a when viewed from the groove 19 on the outer peripheral surface 16. Only the cured region 15 is exposed in the region located on the outer peripheral side as viewed from 19. However, in the present disclosure, on the outer peripheral surface 16, both the cured region 15 and the non-cured region 18 may be exposed only in the region on the outer peripheral side of the inner ring member 3 a as viewed from the groove 19. Both the area on the outer peripheral side as viewed from 19 and the area located near the central axis may be used.

  If the surplus portions 12, 13 (see FIG. 9) are not formed when the heat treatment is performed as described above, the outer ring 2 (see FIG. 2) in the inner ring member 3a as shown in FIG. A hardened region 15 is formed on the entire outer peripheral surface 16 which is an opposing surface. This is because the entire outer peripheral surface 16 of the inner ring member 3a is heated by induction heating because the surplus portions 12 and 13 do not exist.

  Furthermore, an assembly process is performed as a process (S70). In this step (S70), the inner ring member 3a produced as described above and the inner ring member 3b and the outer ring 2 produced in the same manner as the inner ring member 3a are separately prepared as rollers 6 (FIG. 2), a cage 7 (see FIG. 2), an inner ring spacer 4 (see FIG. 2), and the like, thereby assembling the double row tapered roller bearing 1 as shown in FIGS. With the above procedure, the manufacturing method of the double row tapered roller bearing in the present embodiment is completed. From a different point of view, the manufacturing method of the double-row tapered roller bearing 1 shown in FIGS. 1 and 2 prepares the race rings (the outer ring 2, the inner ring members 3a and 3b, and the inner ring spacer 4 shown in FIG. 2). And a step of preparing the tapered roller 6 and a step of assembling the double-row tapered roller bearing 1 by combining the races. The bearing rings (inner ring members 3a, 3b) are manufactured by the above-described manufacturing method of the bearing rings.

In the present embodiment, in the step (S30), the molded body is heated by relatively rotating the coil 121 arranged so as to face a part of the rolling surface 11 of the molded body along the circumferential direction. A region is formed. Therefore, it is possible to employ a small coil 121 with respect to the outer shape of the molded body, and the manufacturing cost of the quenching apparatus can be suppressed even when a large molded body is hardened by hardening. Moreover, in this Embodiment, the whole heating area | region is cooled simultaneously to the temperature below _Ms point. Therefore, it becomes possible to form the hardening area | region 15 which is a cyclic | annular hardening hardening area | region homogeneous in the circumferential direction, and it is suppressed that a residual stress concentrates on a one part area | region.

  Further, in the present embodiment, in step (S30), coil 121 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. Further, in the present embodiment, in the step (S35), the molded body is held in a state where heating is stopped. Therefore, temperature variations in the circumferential direction of the molded body can be suppressed.

  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 S53C, SUP13, SCM445, SAE standard 8660H can be adjusted.

  In this step (S20), the shot blasting process may be performed while the molded body is cooled by spraying hard particles together with gas on the molded body. Thereby, since the shot blast 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 is removed, and the characteristics of the inner ring member 3a resulting from the generation of the scale. 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.

  Furthermore, in the step (S30), the molded body may be rotated at least once, but it is preferable to rotate a plurality of times in order to suppress temperature variation in the circumferential direction and achieve more uniform quench hardening. . That is, it is preferable that the coil 121 as the induction heating coil relatively rotate two or more times along the circumferential direction of the rolling surface 11 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.

<Operation effect of the above manufacturing method>
The method for manufacturing a bearing ring according to the present disclosure illustrated in FIGS. 4 to 9 is a method for manufacturing a bearing ring of a double row tapered roller bearing, and includes a step of preparing a molded body as described above (S10), and heating. A step of forming a region (S30), a step of holding the molded body in a state where heating is stopped (S35), a step of cooling (S40), and a step of removing (S60) are provided. In the step of preparing the formed body (S10), a formed body is prepared which is made of steel and has a bottom surface formed with an annular groove 19 to be the rolling surface 11 of the race. In the step of forming the heating region (S30), the formed body is induction-heated to form a heating region including the bottom surface of the groove 19 and heated to a temperature of A ₁ point or higher. The step (S35) of holding the molded body in a state where heating is stopped is performed after the step (S30) of forming the heating region and before the step of cooling (S40). In the cooling step (S40), the entire heating region is simultaneously cooled to a temperature not higher than the M _s point. In the step of preparing the molded body (S10), the region adjacent to the groove 19 in the molded body includes surplus portions 12 and 13 that extend outward from the position that should be the outer peripheral surface of the race. In the removing step (S60), after the cooling step (S40), the surplus portions 12, 13 are removed from the molded body.

  If it does in this way, since a quenching process can be selectively performed to the heating area | region including the bottom face of the groove | channel 19 which should become the rolling surface 11 of the inner ring member 3a which comprises a bearing ring by induction heating, a carburizing-proof carburizing process is carried out. The manufacturing process of the bearing ring can be simplified and the time required for the process can be shortened as compared with the case where the accompanying carburizing heat treatment is performed. For this reason, the manufacturing cost of a bearing ring can be reduced.

  Further, since the quenching process is performed in a state where the surplus portions 12 and 13 are present adjacent to the groove 19 to be heated, the opening end portion of the groove 19 when there is no surplus portions 12 and 13, that is, the groove The connection part (corner part) between the inner peripheral surface of 19 and the outer peripheral surface of the inner ring member 3a as a raceway ring is overheated or cooled down, thereby reducing the possibility of occurrence of defects such as burning cracks in the part. . That is, the above-described surplus portions 12 and 13 are formed, so that the heating state and the cooling state around the groove 19 in the heating region forming step (S30) and the cooling step (S40) are made uniform. be able to. If it says from a different viewpoint, generation | occurrence | production of the nonuniformity of the quenching by the mass effect in the circumference | surroundings of the groove | channel 19 can be suppressed by forming the said surplus parts 12 and 13. FIG.

  In the method for manufacturing a race, the molded body may have an annular shape as shown in FIG. In the step of preparing the molded body (S10), the surplus portions 12 and 13 of the molded body may be arranged in an annular shape so as to sandwich the groove 19 in the central axis direction of the molded body. In this case, since the surplus portions 12 and 13 are disposed so as to be adjacent to the entire circumference of the groove 19, it is possible to suppress the occurrence of uneven quenching of the entire groove 19.

  In the method for manufacturing a bearing ring, in the step of preparing a molded body (S10), an angle θ (see FIG. 2) formed by the bottom surface of the groove 19 of the molded body and the central axis may be 40 ° or more and 50 ° or less. . In this case, in the so-called steep double-row tapered roller bearing raceway (inner ring member 3a) in which the angle θ is in the numerical range as described above, the portion adjacent to the groove 19 and the groove on the outer circumferential surface of the raceway ring. Differences easily occur in the heating state and cooling state during the quenching process between the portion connected to the bottom surface of 19. Therefore, the track ring manufacturing method according to the present disclosure is particularly effective.

  In the above-described method for manufacturing a bearing ring, in the step of preparing a molded body (S10), carbon of 0.43% to 0.65% by mass and silicon of 0.15% to 0.35% by mass are prepared. 0.60% by mass to 1.10% by mass manganese, 0.30% by mass to 1.20% by mass chromium, and 0.15% by mass to 0.75% by mass molybdenum. A formed body may be prepared which is contained and made of steel composed of the remaining iron and impurities.

  Moreover, in the manufacturing method of the said bearing ring, in a process (S10) which prepares a molded object, 0.43 mass% or more and 0.65 mass% or less carbon, and 0.15 mass% or more and 0.35 mass% or less. 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, and 0.15 mass% or more and 0.75 mass% or less molybdenum And the compact which is 0.35 mass% or more and 0.75 mass% or less of nickel, and consists of steel which consists of remainder iron and an impurity 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 is not an essential component in the steel constituting the raceway ring of the present invention, but may be added when the steel constituting the raceway ring requires particularly high hardenability, such as when the outer shape of the raceway ring is large. it can. 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 further includes a step of performing a normalizing process on the formed 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.

  The double row tapered roller bearing manufacturing method shown in FIG. 1 and FIG. 2 assembles a double row tapered roller bearing by combining the step of preparing the race ring, the step of preparing the tapered roller, and the race ring place. A process. The inner ring members 3a and 3b constituting the bearing ring are manufactured by the method for manufacturing the bearing ring. In this way, it is possible to obtain the double-row tapered roller bearing 1 including the inner ring members 3a and 3b having sufficient characteristics without causing defects such as burning cracks and without increasing the manufacturing cost. .

(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 121 in the step (S30).

That is, referring to FIG. 10, in the step (S30) in the second embodiment, a pair of coils 121 is arranged with the molded body interposed therebetween. The molded body is rotated in the direction of the arrow α, and a high frequency current is supplied to the coil 121 from a power source (not shown). Thereby, the surface layer region including the rolling surface 11 of the formed body 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.

  Referring to FIG. 11, in the step (S30) in the second embodiment, a plurality of (three or more: six in this case) coils are formed along the rolling surface 11 formed on the outer peripheral surface of the molded body. 121 is arranged. As in the case of the first embodiment, the molded body is rotated in the direction of arrow α, and a high frequency current is supplied to the coil 121 from a power source (not shown). Thereby, the surface layer region including the rolling surface 11 of the formed body is induction-heated to a temperature equal to or higher than the A1 point, and an annular heating region 11A along the rolling surface 11 is formed.

  Thus, by arranging a plurality of coils 121 along the circumferential direction of the molded body, 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 achieves uniform firing. This is a method for manufacturing a raceway ring that can be cured. Moreover, in order to further suppress the temperature variation in the circumferential direction, the coils 121 are preferably arranged at equal intervals in the circumferential direction of the molded body.

(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 122 in the step (S30).

  That is, with reference to FIG. 12, in the step (S30) in the third embodiment, the temperature at a plurality of locations (here, 4 locations) on rolling surface 11 that is the heating region is measured. More specifically, in the step (S30) of the third embodiment, a plurality of thermometers 122 are arranged at equal intervals along the circumferential direction of the rolling surface 11 of the molded body.

  Thereby, since the temperature of a plurality of locations is measured simultaneously in the circumferential direction of the rolling surface 11, the molded body is rapidly cooled after confirming that uniform heating is achieved in the circumferential direction of the rolling surface 11, A quench hardening process 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 the above embodiment, the case where the coil 121 is fixed and the molded body is rotated has been described. However, the molded body may be fixed and the coil 121 may be rotated in the circumferential direction of the molded body. The coil 121 may be relatively rotated along the circumferential direction of the molded body by rotating both of the molded bodies. However, since the coil 121 requires wiring for supplying current to the coil 121, it is often reasonable to fix the coil 121 as described above.

  Furthermore, the length of the coil 121 as the induction heating member in the circumferential direction of the molded body can be appropriately determined so as to achieve efficient and uniform heating. For example, the length of the region to be heated is 1 / The length can be about 12, that is, the central angle with respect to the central axis of the compact (orbital ring) is 30 °.

  Further, in the above embodiment, the case where the heat treatment and manufacture of the inner ring of the radial type rolling bearing is performed as an example of the ring-shaped member has been described, but the ring-shaped member to which the present invention is applicable is not limited thereto, For example, it may be an outer ring of a radial type rolling bearing or a raceway ring of a thrust type bearing. Furthermore, the ring-shaped member to which the present invention can be applied is not limited to the bearing ring, and the present invention can be applied to heat treatment and production of various ring-shaped members made of steel. Here, in the step (S30), for example, when the outer ring of the radial type rolling bearing is heated, the coil 121 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 121 may be disposed so as to face the rolling surface formed on the end surface side of the molded body.

  Furthermore, in the above-described embodiment, only the surface layer portion including the rolling surface of the bearing ring of the rolling bearing is quenched by utilizing the feature of induction hardening that can partially quench and harden the workpiece. Although the case where the partial hardening which hardens | cures was implemented was demonstrated, this invention is not applicable only to partial hardening, For example, it can apply also when hardening and hardening the whole bearing ring.

  Although the embodiment of the present invention has been described above, the above-described embodiment can be variously modified. The scope of the present invention is not limited to the above-described embodiment. The scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  This embodiment is particularly advantageously applied to a double-row tapered roller bearing applied to a wind power generator.

  DESCRIPTION OF SYMBOLS 1 Bearing, 2 Outer ring, 3a, 3b Inner ring member, 4 Inner ring spacer, 5 Inner ring, 6 Roller, 7 Cage, 8 Bolt hole, 9 Rolling surface, 10 Wind power generator, 11 Rolling surface, 12, 13 Surplus part, 14 dotted line, 15 hardened area, 16 outer peripheral surface, 17 boundary part, 18 non-hardened area, 19 groove, 20 rotor head, 22 spindle, 25 central axis, 30 blades, 40 speed increaser, 50 generator, 60 main bearing, 61 output shaft, 90 nacelle, 100 tower, 121 coil, 121A induction heating region, 122 thermometer.

Claims (13)

A method of manufacturing a raceway for a double row tapered roller bearing,
Preparing a molded body made of steel and having a bottom surface formed with an annular groove on the outer peripheral surface to be a rolling surface of the raceway;
An induction heating coil that is arranged so as to face a part of the groove and induction-heats the molded body is relatively rotated along the circumferential direction of the groove, thereby including the bottom surface of the groove, and A ₁ Forming a heated region heated to a temperature above the point;
Simultaneously cooling the entire heating area to a temperature below the M _s point;
After the step of forming the heating region, before the step of cooling, the step of holding the molded body in a state where heating is stopped,
In the holding step, a method for manufacturing a bearing ring, wherein variation in the temperature in the circumferential direction in the heating region is suppressed to 20 ° C. or less. In the step of preparing the molded body, the area adjacent to the groove in the molded body includes a surplus portion that extends outward from a position to be an outer peripheral surface of the race,
The manufacturing method of the bearing ring of Claim 1 provided with the process of removing the said surplus part from the said molded object after the said process to cool. The molded body has an annular shape,
The track ring manufacturing according to claim 2, wherein in the step of preparing the molded body, the surplus portion of the molded body is arranged in an annular shape so as to sandwich the groove in a central axis direction of the molded body. Method.   The method of manufacturing a bearing ring according to claim 3, wherein in the step of preparing the molded body, an angle formed by the bottom surface of the groove of the molded body and the central axis is 40 ° or more and 50 ° or less.   5. The method for manufacturing a bearing ring according to claim 1, wherein, in the step of forming the heating region, a plurality of the induction heating coils are arranged along the circumferential direction. 6.   The method for manufacturing a bearing ring according to claim 5, wherein in the step of forming the heating region, the plurality of induction heating coils are arranged at equal intervals along the circumferential direction.   The method of manufacturing a bearing ring according to any one of claims 1 to 6, wherein, in the step of forming the heating region, the induction heating coil relatively rotates two or more times along the circumferential direction.   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 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 10, 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 11, 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. A process of preparing a bearing ring;
Preparing a cone-shaped roller;
A step of assembling a double row tapered roller bearing by combining the raceway and the roller,
The said ring is a manufacturing method of the double row tapered roller bearing manufactured by the manufacturing method of the bearing ring of any one of Claims 1-12.

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