JP2016020529A - Production method of bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production method of a bearing in which a plurality of heated parts are uniformly heated.SOLUTION: A production method of a bearing comprises the steps of: preparing a workpiece and a heating apparatus for performing induction heating the workpiece; and performing induction heating the workpiece with the heating apparatus. The workpiece is used as a member 12 constituting a bearing 10 after performing induction heating with the heating apparatus, and comprises a raceway surface 12A. The raceway surface is brought into contact with a plurality of rolling bodies 18 provided in the bearing. The workpiece also comprises a body and an attachment part 22A. The attachment part is formed in an outer peripheral surface of the body. The body comprises a plurality of heated parts. The heating apparatus comprises an induction heating coil and a shielding member. The induction heating coil is arranged around the workpiece. The shielding member is made of soft magnetic material. The shielding member is arranged between the workpiece and the induction heating coil in a direction crossing an axial direction.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for manufacturing a bearing, and more particularly, to a method for heat treatment of members constituting the bearing.

  A vehicle such as an automobile includes a plurality of wheels. Each of the plurality of wheels is rotatably supported by a bearing.

  The bearing includes, for example, an outer ring, an inner shaft, an inner ring, a plurality of first rolling elements, and a plurality of second rolling elements. The outer ring has a cylindrical shape. The outer ring includes a first raceway surface and a second raceway surface. The first raceway surface and the second raceway surface are formed on the inner peripheral surface of the outer ring and are separated in the axial direction of the outer ring. The inner shaft is disposed inside the outer ring. The inner ring is fixed to the inner shaft. The inner shaft includes a raceway surface. The track surface is formed on the outer peripheral surface of the inner shaft. The inner ring includes a raceway surface. The track surface is formed on the outer peripheral surface of the inner ring. The plurality of first rolling elements are in contact with the first raceway surface of the outer ring and the raceway surface of the inner shaft. The plurality of second rolling elements are in contact with the second raceway surface of the outer ring and the raceway surface of the inner ring.

  The outer ring and the inner shaft include a hardened layer. The hardened layer of the outer ring is formed, for example, at a part including the first raceway surface and a part including the second raceway surface. The hardened layer of the inner shaft is formed in, for example, a part including the raceway surface and a part including a surface overlapping the inner ring. The hardness of the hardened layer is adjusted by quenching and tempering, for example, as described in JP-A-2009-191912 and JP-A-2005-98320.

JP 2009-191912 A JP 2005-98320 A

  The outer ring and the inner shaft include a mounting portion. The attachment portion is formed on the outer peripheral surface. The outer ring attachment portion is attached to a suspension device, for example. The attachment portion of the inner shaft is attached to, for example, a wheel (specifically, a wheel), a brake disk, or the like.

  An induction heating coil is used for tempering. When forming a hardened layer in a plurality of parts, depending on the positional relationship between the mounting portion, the plurality of parts (a plurality of heated parts) where the hardened layer is to be formed, and the induction heating coil, the plurality of heated parts are uniform. It becomes difficult to heat.

  An object of the present invention is to provide a method for manufacturing a bearing, which uniformly heats a plurality of heated portions.

  A bearing manufacturing method according to an embodiment of the present invention includes a step (A) and a step (B). In the step (A), a work and a heating device are prepared. The heating device induction heats the workpiece. In the step (B), the work is induction heated by a heating device. The workpiece is used as a member constituting the bearing after induction heating by the heating device. The member includes a raceway surface. The raceway surface is in contact with a plurality of rolling elements provided in the bearing. The workpiece includes a main body and a mounting portion. The attachment portion is formed on the outer peripheral surface of the main body. The main body includes a plurality of heated portions. The plurality of heated portions are located apart in the axial direction in which the central axis of the main body extends. The plurality of heated portions include at least the raceway surface. The heating device includes an induction heating coil and a shielding member. The induction heating coil is disposed around the work. The shielding member is made of a soft magnetic material. The shielding member is disposed between the work and the induction heating coil in a direction crossing the axial direction. When viewed from the axial direction, the induction heating coil overlaps the mounting portion.

  In the bearing manufacturing method according to the embodiment of the present invention, a plurality of heated parts can be heated uniformly.

It is sectional drawing which shows an example of the bearing manufactured by the manufacturing method of the bearing by embodiment of this invention. It is explanatory drawing which shows an example of the heating apparatus used in order to form a hardened layer. It is explanatory drawing which shows an example of the positional relationship of an induction heating coil, a shielding member, and a workpiece | work. It is sectional drawing which shows an example of the positional relationship of the site | part which should form the hardening layer, and induction heating coil in case a workpiece | work is a member used as an outer ring | wheel after tempering. It is sectional drawing which shows an example of the positional relationship of one of a some to-be-heated site | parts, and an attaching part. It is sectional drawing which shows an example of the positional relationship of the site | part which should form a hardened layer, and an induction heating coil in case a workpiece | work is a member used as an inner shaft after tempering.

  A bearing manufacturing method according to an embodiment of the present invention includes a step (A) and a step (B). In the step (A), a work and a heating device are prepared. The heating device induction heats the workpiece. In the step (B), the work is induction heated by a heating device. The workpiece is used as a member constituting the bearing after induction heating by the heating device. The member includes a raceway surface. The raceway surface is in contact with a plurality of rolling elements provided in the bearing. The workpiece includes a main body and a mounting portion. The attachment portion is formed on the outer peripheral surface of the main body. The main body includes a plurality of heated portions. The plurality of heated portions are located apart in the axial direction in which the central axis of the main body extends. The plurality of heated portions include at least the raceway surface. The heating device includes an induction heating coil and a shielding member. The induction heating coil is disposed around the work. The shielding member is made of a soft magnetic material. The shielding member is disposed between the work and the induction heating coil in a direction crossing the axial direction. When viewed from the axial direction, the induction heating coil overlaps the mounting portion.

  A magnetic field is generated due to energization of the induction heating coil. An eddy current that cancels the magnetic field flows through the work disposed inside the induction heating coil. Each of the plurality of heated parts is heated by Joule heat resulting from the eddy current.

  Here, among the plurality of heated portions, the heated portion closest to the attachment portion in the axial direction is less likely to be heated than the other heated portions. Therefore, there is a possibility that the heating may vary among the plurality of heated parts.

  In the above manufacturing method, a shielding member made of a soft magnetic material is disposed between the main body and the induction heating coil. Therefore, the magnetic field generated due to energization of the induction heating coil acts weakly on the main body and acts strongly on the mounting portion. As a result, a weak eddy current is generated in the main body, and a strong eddy current is generated in the mounting portion. The magnitude of Joule heat is due to the strength of eddy currents. That is, the main body is hardly heated, but the attachment portion is easily heated. Here, the heated portion closest to the attachment portion in the axial direction is heated mainly by heat conduction from the attachment portion. The other heated parts are heated mainly by Joule heat caused by eddy currents generated in the main body. Therefore, for example, by appropriately setting the shape and thickness of the shielding member (thickness in the direction perpendicular to the axial direction), the positional relationship between the shielding member and the workpiece, the heated portion closest to the mounting portion in the axial direction The difference between the amount of heating and the amount of heating of other heated parts can be reduced. As a result, the heating is less likely to vary between the heated portion closest to the mounting portion in the axial direction and the other heated portion.

  The induction heating coil overlaps the mounting portion when viewed from the axial direction. Thereby, when viewed from the axial direction, the induction heating coil can be disposed closer to the main body as compared with the case where the attachment portion is located inside the induction heating coil. As a result, the energization amount to the induction heating coil can be reduced.

  One of the plurality of heated portions may overlap at least a part of the attachment portion when viewed from a direction perpendicular to the axial direction.

  According to the above manufacturing method, even in such a case, it is possible to suppress variation in heating among the plurality of heated portions.

  The plurality of heated parts may include a first heated part. The first heated portion is closest to the attachment portion when viewed from the direction perpendicular to the axial direction. When viewed from a direction perpendicular to the axial direction, the first heated portion is separated from the attachment portion. When viewed from a direction perpendicular to the axial direction, the distance between the first heated portion and the mounting portion is 10 mm or less.

  According to the above manufacturing method, even in such a case, it is possible to suppress variation in heating among the plurality of heated portions.

  The “distance between the first heated portion and the attachment portion when viewed from the direction perpendicular to the axial direction” is the end closer to the attachment portion of the first heated portion and the first heated portion of the attachment portion. The distance from the end closer to the part.

  The plurality of heated parts may include a second heated part. The second heated portion is farthest from the mounting portion when viewed from the direction perpendicular to the axial direction. The induction heating coil is disposed closer to the second heated portion than the attachment portion in the axial direction. That is, the induction heating coil is disposed so that the second heated portion is located with respect to the attachment portion.

  In this case, it becomes easy to arrange the induction heating coil around the workpiece.

  Preferably, when viewed from the direction perpendicular to the axial direction, both ends of the induction heating coil in the axial direction overlap the shielding member.

  In this case, it can be ensured that the magnetic field generated due to energization of the induction heating coil acts weakly on the main body. As a result, it becomes easy to suppress variation in heating among a plurality of heated parts.

  Preferably, the length of the shielding member in the axial direction is the same as the length of the induction heating coil in the axial direction. The shielding member is disposed at the same position as the induction heating coil in the axial direction.

  In this case, the length of the shielding member in the axial direction can be set to the minimum necessary size.

  Examples of the soft magnetic material include iron, silicon steel, permalloy, sendust, permendur, and soft ferrite. The soft magnetic material is preferably silicon steel.

  Preferably, the shielding member is fixed to the induction heating coil.

  In this case, the shielding member and the induction heating coil can be handled integrally.

  The method for fixing the shielding member to the induction heating coil is not particularly limited. For example, the shielding member may be fixed to the induction heating coil with a bolt, or the shielding member may be fixed to the induction heating coil with an adhesive.

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

  FIG. 1 shows a bearing 10. The bearing 10 is an example of a bearing manufactured by the manufacturing method according to the embodiment of the present invention. The bearing manufactured by the above manufacturing method is not limited to the configuration shown in FIG.

[Bearing configuration]
Referring to FIG. 1, bearing 10 includes an outer ring 12, an inner shaft 14, an inner ring 16, a plurality of rolling elements 18, and a plurality of rolling elements 20. In FIG. 1, a cage that holds a plurality of rolling elements 18, a cage that holds a plurality of rolling elements 20, a seal member disposed between the outer ring 12 and the inner shaft 14, and an attachment to the outer ring 12. The illustrated cover is not shown.

  The outer ring 12 is made of, for example, bearing steel. The outer ring 12 includes a main body 121. The main body 121 has a cylindrical shape.

  The main body 121 includes a raceway surface 12A and a raceway surface 12B. The raceway surface 12 </ b> A and the raceway surface 12 </ b> B are formed on the inner peripheral surface of the main body 121. The raceway surface 12A and the raceway surface 12B are separated in the axial direction. Here, the axial direction is a direction in which the main axis 121, that is, the central axis L1 of the outer ring 12 extends.

  The outer ring 12 further includes a flange 22. The flange 22 is formed on the outer peripheral surface of the main body 121. The flange 22 is formed continuously in the circumferential direction around the central axis L1. That is, the flange 22 is formed in an annular shape.

  The flange 22 includes a plurality of attachment portions 22A. The plurality of attachment portions 22A are formed, for example, at equal intervals in the circumferential direction.

  Each of the plurality of attachment portions 22 </ b> A includes a hole 24. The suspension device is fixed to the outer ring 12 by bolts inserted into the holes 24.

  The inner shaft 14 is made of bearing steel, for example. The inner shaft 14 is disposed inside the outer ring 12. The inner shaft 14 is disposed coaxially with the outer ring 12. That is, the inner shaft 14 is disposed on the central axis L1.

  The inner shaft 14 includes a main body 141. The main body 141 includes a large diameter portion 14A, a medium diameter portion 14B, and a small diameter portion 14C.

  A seal member is disposed between the outer ring 12 and the large diameter portion 14A. The seal member includes a metal core fixed to the outer ring 12 and a seal rubber formed integrally with the metal core. A sliding surface 25 on which the seal rubber slides is formed on the outer peripheral surface of the large diameter portion 14A.

  The medium diameter portion 14B has a smaller diameter than the large diameter portion 14A. The medium diameter portion 14B is located next to the large diameter portion 14A in the axial direction. The middle diameter portion 14 </ b> B includes a raceway surface 26.

  The small diameter portion 14C has a smaller diameter than the medium diameter portion 14B. The small diameter portion 14C is located next to the medium diameter portion 14B in the axial direction. The small diameter portion 14 </ b> C includes an outer peripheral surface 32.

  The inner shaft 14 further includes a flange 14D. The flange 14 </ b> D is formed on the outer peripheral surface of the main body 141. The flange 14D is formed continuously in the circumferential direction. That is, the flange 14D is formed in an annular shape. The flange 14D has a larger diameter than the large diameter portion 14A. The flange 14D is located next to the large diameter portion 14A in the axial direction.

  The flange 14 </ b> D includes a plurality of holes 28. For example, the plurality of holes 28 are formed at equal intervals in the circumferential direction. A wheel (specifically, a wheel), a brake disk, or the like is attached to the inner shaft 14 by a bolt 29 inserted into each of the plurality of holes 28.

  The inner ring 16 is fixed to the inner shaft 14. Specifically, the inner ring 16 is disposed around the small diameter portion 14C and is fixed by a caulking portion 30 provided in the small diameter portion 14C.

  The inner ring 16 includes a raceway surface 16A. The raceway surface 16 </ b> A is formed on the outer peripheral surface of the inner ring 16.

  The plurality of rolling elements 18 are disposed between the outer ring 12 and the inner shaft 14. The plurality of rolling elements 18 are arranged at equal intervals in the circumferential direction by a cage. Each of the plurality of rolling elements 18 contacts the raceway surface 12 </ b> B and the raceway surface 26.

  The plurality of rolling elements 20 are disposed between the outer ring 12 and the inner ring 16. The plurality of rolling elements 20 are arranged at equal intervals in the circumferential direction by a cage. Each of the plurality of rolling elements 20 contacts the raceway surface 12A and the raceway surface 16A.

[Bearing manufacturing method]
The bearing 10 is manufactured by the following manufacturing method, for example.

  First, the outer ring 12 is arranged around the inner shaft 14. At this time, the plurality of rolling elements 18 are arranged between the raceway surface 12B and the raceway surface 26. The seal member is press-fitted into the outer ring 12.

  Subsequently, the inner ring 16 is fixed to the inner shaft 14. Specifically, first, the inner ring 16 is arranged around the small diameter portion 14C. At this time, the plurality of rolling elements 20 are arranged between the raceway surface 12A and the raceway surface 16A. Thereafter, the inner ring 16 is fixed to the inner shaft 14 by the caulking portion 30. Thereby, the bearing 10 is manufactured.

[Tempering outer ring and inner shaft]
A hardened layer is formed on the outer ring 12 and the inner shaft 14. Specifically, the hardened layer of the outer ring 12 is formed in a part including the raceway surface 12A and a part including the raceway surface 12B. The hardened layer of the inner shaft 14 is formed in a part including the sliding surface 25, a part including the raceway surface 26, and a part including the outer peripheral surface 32 of the small diameter portion 14C. For example, these hardened layers are formed by quenching, and then the hardness is adjusted by tempering.

  FIG. 2 shows an example of the heating device 100. The heating device 100 is used to lower the hardness of the hardened layer by tempering. The heating device 100 is a so-called induction heating device. In addition, another heating apparatus is used for quenching.

  Referring to FIG. 2, heating device 100 includes induction heating coil 102, shielding member 104, high frequency power source 106, and matching unit 108.

  The induction heating coil 102 induction-heats the workpiece 110. The shielding member 104 weakens a magnetic field generated due to energization of the induction coil 102. Details of the workpiece 110, the induction heating coil 102, and the shielding member 104 will be described later.

  The high frequency power source 106 generates high frequency energy. The high frequency power supply 106 supplies the generated high frequency energy to the matching unit 108.

  The matching unit 108 is a so-called transformer. The matching unit 108 matches the high frequency energy supplied from the high frequency power source 106 and supplies the high frequency energy to the induction heating coil 102.

  Specifically, the matching unit 108 supplies an alternating current having a predetermined frequency to the induction heating coil 102. Thereby, a magnetic field is generated. As a result, an eddy current is generated in the workpiece 110. Due to the Joule heat caused by the eddy current, a portion (a portion to be heated) where a hardened layer is to be formed in the workpiece 110 can be heated.

  In addition, the workpiece | work 110 may rotate to the circumferential direction at the time of induction heating, and does not need to rotate.

  Details of the workpiece 110, the induction heating coil 102, and the shielding member 104 will be described with reference to FIG. FIG. 3 shows the positional relationship among the induction heating coil 102, the shielding member 104, and the workpiece 110. In FIG. 3, the direction in which the central axis L1 of the workpiece 110 extends (hereinafter referred to as the axial direction) coincides with the vertical direction.

  The workpiece 110 is a member used as the outer ring 12 or the inner shaft 14 after tempering. The workpiece 110 includes a main body 110A and a mounting portion 110B.

  When the workpiece 110 is a member used as the outer ring 12 after tempering, the main body 110A corresponds to the main body 121, and the attachment portion 110B corresponds to the attachment portion 22A. When the workpiece 110 is a member used as the inner shaft 14 after tempering, the main body 110A corresponds to the main body 141, and the mounting portion 110A corresponds to the flange 14D.

  Referring to FIG. 3, induction heating coil 102 is arranged around work 110. Specifically, the induction heating coil 102 is disposed around the main body 110A and above the attachment portion 110B. That is, the induction heating coil 102 is disposed on one side (above) in the axial direction with respect to the attachment portion 110B in the axial direction.

  The induction heating coil 102 may be formed, for example, by bending a pipe made of a conductive material such as metal into a spiral shape. Alternatively, a plurality of surrounding portions formed by bending a pipe made of a conductive material such as a metal into a substantially circular shape are arranged in the vertical direction, and the circumferential direction of each of the two circumferential portions adjacent in the vertical direction You may connect and form an end with the connection part extended in an up-down direction.

  In the present embodiment, the induction heating coil 102 makes two turns around the main body 110A. That is, the induction heating coil 102 includes a first circulation part 102A and a second circulation part 102B. The first circulating portion 102A is located closer to the mounting portion 110B than the second circulating portion 102B in the axial direction.

  The number of turns of the induction heating coil 102 is not limited to two. The number of turns of the induction heating coil 102 is appropriately increased or decreased according to the shape of the workpiece 110, for example.

  The size of the gap formed between the first turning portion 102A and the main body 110A is preferably the same as the size of the gap formed between the second turning portion 102B and the main body 110A. Thereby, the dispersion | variation in the heating in the axial direction of 110 A of main bodies can be suppressed.

  When the gap formed between the induction heating coil 102 and the main body 110A changes in the axial direction, the number of turns of the induction heating coil 102 is increased in a portion where the gap is large, and the induction heating coil is formed in a portion where the gap is small. The number of turns of 102 may be reduced. Thereby, the dispersion | variation in the heating in the axial direction of 110 A of main bodies can be suppressed.

  The size of the gap formed between the induction heating coil 102 and the mounting portion 110B may be the same as or different from the size of the gap formed between the induction heating coil 102 and the main body 110A. Also good.

  When the induction heating coil 102 is formed by bending a pipe made of a conductive material such as metal, the cross-sectional shape of the pipe is not particularly limited. For example, it may be circular or rectangular.

  The induction heating coil 102 is disposed at a position that overlaps the attachment portion 110B when viewed from the axial direction. Induction heating coil 102 is arranged coaxially with main body 110A.

  Referring to FIG. 3, shielding member 104 is disposed between main body 110 </ b> A and induction heating coil 102 in a direction perpendicular to the axial direction (hereinafter referred to as a radial direction). That is, the shielding member 104 is not disposed between the induction heating coil 102 and the attachment portion 110B.

  The shielding member 104 is made of a soft magnetic material. Examples of the soft magnetic material include iron, silicon steel, permalloy, sendust, permendur, and soft ferrite.

  The shielding member 104 is formed, for example, by bending a silicon steel plate into a cylindrical shape. In this case, a gap is formed between one end in the circumferential direction of the shielding member 104 and the other end in the circumferential direction. An insulating member made of an insulating material such as a synthetic resin is disposed in the gap. Thereby, damage to the shielding member 104 due to energization can be prevented.

  The shielding member 104 may include a plurality of plate materials that are curved in an arc shape when viewed from the axial direction. In this case, a gap is formed between two plate materials adjacent in the circumferential direction around the central axis L1. An insulating member made of an insulating material such as a synthetic resin is disposed in the gap.

  The radial thickness of the shielding member 104 can be adjusted, for example, by changing the number of overlapped silicon steel plates that are bent into a cylindrical shape and arranged in the radial direction.

  The length of the shielding member 104 in the vertical direction is preferably not less than the length of the induction heating coil 102 in the vertical direction.

  Specifically, when the center of the shielding member 104 in the vertical direction and the center of the induction heating coil 102 in the vertical direction are aligned at the same position in the axial direction, the induction heating coil 102 is viewed from the radial direction. It is preferable that the upper end and the lower end of each overlap the shielding member 104. Here, when the upper and lower ends in the vertical direction of the induction heating coil 102 overlap the shielding member 104, the upper end of the induction heating coil 102 is at the same position as the upper end of the shielding member 104 and the lower end of the induction heating coil 102. In the same position as the lower end of the shielding member 104.

  In a strict sense, the upper end of the shielding member 104 does not have to be at the same position as the upper end of the induction heating coil 102. If the magnetic field generated due to the energization of the induction heating coil 102 can be weakened from acting on the workpiece 110, the upper end of the shielding member 104 is positioned below the upper end of the induction heating coil 102. May be.

  Similarly, the lower end of the shielding member 104 does not have to be at the same position as the lower end of the induction heating coil 102. If the magnetic field generated due to the energization of the induction heating coil 102 can be weakened from acting on the workpiece 110, the lower end of the shielding member 104 is positioned above the lower end of the induction heating coil 102. May be.

  In order to arrange the induction heating coil 102 near the mounting portion 110B, the lower end of the shielding member 104 is positioned at the same position as the lower end of the induction heating coil 102 or above the lower end of the induction heating coil 102. Is preferred.

  The shielding member 104 may be fixed to the induction heating coil 102 or may be fixed to a member other than the induction heating coil 102. As a method of fixing the shielding member 104 to the induction heating coil 102, for example, fixing with a bolt, adhesion with an adhesive, or the like can be considered. A gap may be formed between the shielding member 104 and the induction heating coil 102.

  The radial thickness of the shielding member 104 may be substantially constant in the vertical direction or may vary in the vertical direction. As a method of changing the radial thickness of the shielding member 104 in the vertical direction, for example, a plurality of plate-like members having different heights may be superposed in the radial direction. Incidentally, in the example shown in FIG. 3, the thickness of the shielding member 104 is substantially constant in the vertical direction.

  Next, with reference to FIG. 4, the relationship between the part (heated part) where the hardened layer is to be formed and the induction heating coil 102 when the workpiece 110 is a member used as the outer ring 12 after tempering will be described. To do. In FIG. 4, the axial direction of the workpiece 110 (the direction in which the central axis L1 extends) coincides with the vertical direction.

  The workpiece 110 includes a plurality of heated portions 112A and 112B. The plurality of heated portions 112A and 112B are separated in the axial direction. The heated portion 112A includes a raceway surface 12A. The heated portion 112B includes a raceway surface 12B.

  At least a part of the heated portion 112A overlaps the flange 22 (mounting portion 22A) when viewed from the radial direction (direction perpendicular to the axial direction). That is, the heated portion 112A is located closer to the flange 22 (attachment portion 22A) than the heated portion 112B in the axial direction.

  The induction heating coil 102 is disposed above the flange 22. Here, at least a part of the first circulating portion 102A overlaps the heated portion 112B when viewed from the radial direction. At least a part of the second circulating portion 102B overlaps with a portion located above the heated portion 112B when viewed from the radial direction. The size of the gap formed between the first turning portion 102A and the main body 121 is substantially the same as the size of the gap formed between the second turning portion 102B and the main body 121.

  In the induction heating by the induction heating coil 102, the part located at the center in the vertical direction of the induction heating coil 102 is most easily heated. Here, the center in the vertical direction of the induction heating coil 102 refers to a position that bisects the distance from the lower end of the first rotating portion 102A to the upper end of the second rotating portion 102B when viewed from the radial direction.

  The heated part 112B is located closer to the center in the vertical direction of the induction heating coil 102 than the heated part 112A. That is, the heated part 112A is less likely to be heated than the heated part 112B.

  Here, the shielding member 104 is disposed between the induction heating coil 102 and the main body 121, but is not disposed between the induction heating coil 102 and the flange 22. Therefore, a magnetic field generated due to energization of the induction heating coil 102 acts weakly on the main body 121 and acts strongly on the flange 22 (particularly, the attachment portion 22A). As a result, a weak eddy current is generated in the main body 121, and a strong eddy current is generated in the flange 22 (particularly, the attachment portion 22A). The magnitude of Joule heat is due to the strength of eddy currents. That is, the main body 121 is hardly heated, but the flange 22 (particularly, the attachment portion 22A) is easily heated. Here, the heated portion 112A is heated mainly by heat conduction from the flange 22 (particularly, the attachment portion 22A). The heated portion 112 </ b> B is heated mainly by Joule heat caused by eddy current generated in the main body 121. Therefore, for example, by appropriately setting the shape and thickness of the shielding member 104, the positional relationship between the shielding member 104 and the workpiece 110, the difference between the heating amount of the heated portion 112A and the heated amount of the heated portion 112B. Can be reduced. As a result, the heating is less likely to vary between the heated portion 112A and the heated portion 112B.

  In the example shown in FIG. 4, at least a part of the heated portion 112 </ b> A overlaps with the flange 22 (attachment portion 22 </ b> A) when viewed from the radial direction, but for example, when viewed from the radial direction as illustrated in FIG. 5. The heated portion 112A may be separated from the flange portion 22 (attachment portion 22A). A distance D1 in the axial direction between the heated portion 112A and the flange portion 22 (attachment portion 22A) is, for example, 10 mm or less. In this case, similarly to the case shown in FIG. 4, the heated portion 112 </ b> A is less likely to be heated than the heated portion 112 </ b> B, but the shielding member 104 is disposed between the induction heating coil 102 and the main body 121. Since the shielding member 104 is not disposed between the heating coil 102 and the flange 22 (attachment portion 22A), it is difficult for heating to vary between the heated portion 112A and the heated portion 112B.

  Next, with reference to FIG. 6, in the case where the workpiece 110 is a member used as the inner shaft 14 after tempering, the relationship between the portion where the hardened layer is to be formed (the portion to be heated) and the induction heating coil 102 is as follows. explain. In FIG. 6, the axial direction of the workpiece 110 (the direction in which the central axis L1 extends) coincides with the vertical direction.

  The workpiece 110 includes a plurality of heated portions 114A, 114B, and 114C. The plurality of heated portions 114A, 114B, 114C are separated in the axial direction. The heated portion 114 </ b> A includes a sliding surface 25. The heated portion 114 </ b> B includes the raceway surface 26. The heated portion 114 </ b> C includes the outer peripheral surface 32. The heated portion 114A is positioned closer to the flange portion 14D than the heated portion 114B or the heated portion 114C in the axial direction.

  The induction heating coil 102 is disposed above the flange 14D. Here, at least a part of the first circulating portion 102A overlaps the heated portion 114A when viewed from the radial direction. At least a part of the second circulating portion 102B overlaps the heated portion 114C when viewed from the radial direction. The inner diameter of the first circulating portion 102A is larger than the inner diameter of the second circulating portion 102B. The size of the gap formed between the first turning portion 102A and the main body 141 is substantially the same as the size of the gap formed between the second turning portion 102B and the main body 141.

  The shielding member 104 includes a large diameter portion 104A, an annular portion 104B, and a small diameter portion 104C.

  The large diameter portion 104A extends in the axial direction. At least a part of the large-diameter portion 104A overlaps the first circulating portion 102A when viewed from the radial direction.

  The small diameter portion 104C extends in the axial direction. At least a part of the small diameter portion 104C overlaps with the second circulating portion 102B when viewed from the radial direction.

  The annular portion 104B extends in the radial direction. The annular portion 104B connects the upper end of the large diameter portion 104A and the lower end of the small diameter portion 104C.

  In addition, the shielding member 104 shown in FIG. 6 is implement | achieved by arranging a some board | plate material in the circumferential direction (direction around the central axis L1), for example. Here, each of the plurality of plate members is curved in an arc shape when viewed from the up-down direction, and has a step at an intermediate portion in the up-down direction. An insulating member made of an insulating material is disposed between two plate materials adjacent in the circumferential direction.

  In the induction heating by the induction heating coil 102, the part located at the center in the vertical direction of the induction heating coil 102 is most easily heated. The center of the induction heating coil 102 in the vertical direction is located between the heated part 114B and the heated part 114C as seen from the radial direction.

  As described above, the heated portion 114A is positioned closer to the flange portion 14D than the heated portion 114B or the heated portion 114C in the axial direction. The center of the induction heating coil 102 in the vertical direction is located between the heated part 114B and the heated part 114C as seen from the radial direction. Therefore, the heated portion 114A is farther from the vertical center of the induction heating coil 102 than the heated portion 114B and the heated portion 114C. As a result, the heated part 114A is less likely to be heated than the heated part 114B and the heated part 114C.

  Here, the shielding member 104 is disposed between the induction heating coil 102 and the main body 141, but is not disposed between the induction heating coil 102 and the flange 14D. Therefore, the magnetic field generated due to the energization of the induction heating coil 102 acts weakly on the main body 141 and acts strongly on the flange 14D. As a result, a weak eddy current is generated in the main body 141 and a strong eddy current is generated in the flange 14D. The magnitude of Joule heat is due to the strength of eddy currents. That is, the main body 141 is hardly heated, but the flange 14D is easily heated. Here, the heated portion 114A is heated mainly by heat conduction from the flange 14D. The heated portion 114B and the heated portion 114C are heated mainly by Joule heat caused by eddy current generated in the main body 141. Therefore, for example, by appropriately setting the shape and thickness of the shielding member 104 and the positional relationship between the shielding member 104 and the workpiece 110, the difference in heating amount between the heated portions 114A, 114B, and 114C can be reduced. it can. As a result, it is difficult for heating to vary among the plurality of heated portions 114A, 114B, and 114C.

  As mentioned above, although embodiment of this invention was explained in full detail, these are illustrations to the last, Comprising: This invention is not limited at all by the above-mentioned embodiment.

  For example, in the above embodiment, the bearing 10 has a configuration in which the inner shaft 14 and the inner ring 16 are disposed inside the outer ring 12, but the bearing may have a configuration without the inner shaft.

10: bearing, 121: main body, 141: main body, 14D: flange, 22A: mounting portion, 100: heating device, 102: induction heating coil, 104: shielding member, 110: work, 110A: main body, 110B: mounting portion, 112A: heated part, 112B: heated part, 114A: heated part, 114B: heated part, 114C: heated part

Claims (6)

A bearing manufacturing method comprising:
Preparing a workpiece and a heating device for induction heating the workpiece;
A step of induction heating the workpiece by the heating device,
The workpiece is
Used as a member constituting the bearing after induction heating by the heating device;
The body,
Including an attachment portion formed on the outer peripheral surface of the main body,
The body is
A plurality of heated portions including a raceway surface that is located in the axial direction in which the central axis of the main body extends and is in contact with a plurality of rolling elements included in the bearing;
The heating device is
An induction heating coil disposed around the workpiece;
A shield member made of a soft magnetic material, disposed between the workpiece and the induction heating coil in a direction intersecting the axial direction of the workpiece;
The manufacturing method in which the induction heating coil overlaps the mounting portion when viewed from the axial direction. The manufacturing method according to claim 1,
As viewed from a direction perpendicular to the axial direction, one of the plurality of heated portions overlaps at least a part of the attachment portion. The manufacturing method according to claim 1,
The plurality of heated parts are:
A first heated portion closest to the attachment portion when viewed from a direction perpendicular to the axial direction;
When viewed from a direction perpendicular to the axial direction,
The first heated part is separated from the attachment part,
The distance between the said 1st to-be-heated site | part and the said attaching part is a manufacturing method which is 10 mm or less. The manufacturing method according to claim 1,
The plurality of heated parts are:
A second heated portion farthest from the mounting portion when viewed from a direction perpendicular to the axial direction,
The said induction heating coil is a manufacturing method arrange | positioned in the said axial direction near the said 2nd to-be-heated part rather than the said attaching part. The manufacturing method according to claim 1,
The manufacturing method in which both ends in the axial direction of the induction heating coil overlap the shielding member when viewed from a direction perpendicular to the axial direction. The manufacturing method according to claim 1,
The manufacturing method, wherein the soft magnetic material is silicon steel.

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