WO2023238364A1 - Method of manufacturing rollers for bearings - Google Patents

Method of manufacturing rollers for bearings Download PDF

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Publication number
WO2023238364A1
WO2023238364A1 PCT/JP2022/023407 JP2022023407W WO2023238364A1 WO 2023238364 A1 WO2023238364 A1 WO 2023238364A1 JP 2022023407 W JP2022023407 W JP 2022023407W WO 2023238364 A1 WO2023238364 A1 WO 2023238364A1
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WO
WIPO (PCT)
Prior art keywords
boundary
crowning
circle
inclined surface
boundary circle
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PCT/JP2022/023407
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French (fr)
Japanese (ja)
Inventor
大和 岡田
陽一 沼田
Original Assignee
株式会社ジェイテクト
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Application filed by 株式会社ジェイテクト filed Critical 株式会社ジェイテクト
Priority to PCT/JP2022/023407 priority Critical patent/WO2023238364A1/en
Publication of WO2023238364A1 publication Critical patent/WO2023238364A1/en

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C33/00—Parts of bearings; Special methods for making bearings or parts thereof
    • F16C33/30—Parts of ball or roller bearings
    • F16C33/34—Rollers; Needles
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C33/00—Parts of bearings; Special methods for making bearings or parts thereof
    • F16C33/30—Parts of ball or roller bearings
    • F16C33/58—Raceways; Race rings
    • F16C33/64—Special methods of manufacture

Definitions

  • the present invention relates to a method for manufacturing bearing rollers.
  • the outer diameter surface of the bearing roller is sometimes provided with a crowning in order to relieve the excessive stress load that occurs at the axial end. Crowning is to provide a slight curvature or inclination to the entire region of the generatrix of the outer diameter surface or to both ends in the axial direction (see, for example, Patent Document 1).
  • the crowning portion 106 is formed by bringing the processed surface 202 of the grindstone 200 into contact with the outer circumferential surface 110a of the rough-shaped product 110 and polishing it.
  • the roughly shaped product 110 is a raw material for the bearing roller 100, and becomes the bearing roller 100 by providing the crowning portion 106 and the cylindrical portion 108.
  • the outer peripheral surface 110a of the rough-shaped product 110 has a chamfered portion 112 and a surface to be polished 114.
  • the chamfered portion 112 remains as the chamfered portion 102 of the bearing roller 100.
  • the processed surface 202 has an inclined surface 202a for forming the crowning portion 106 and a cylindrical surface 202b for forming the cylindrical portion 108. Both surfaces 202a and 202b are formed (dressed) into a shape that matches the shapes of the crowning part 106 and the cylindrical part 108.
  • the dressed grindstone 200 is repeatedly used to polish the bearing rollers 100. Both surfaces 202a and 202b of the grindstone 200 gradually deform due to wear due to repeated use. Due to this deformation, the dimensional accuracy of the crowning portion 106 that is formed also gradually decreases. Therefore, after the grindstone 200 has been used a predetermined number of times, it is dressed again and reshaped into a shape that matches the shapes of the crowning part 106 and the cylindrical part 108.
  • the bearing roller 100 is polished by the grindstone 200, as shown in the partial cross-sectional view shown in the broken line circle in FIG. This may occur near the boundary B with the section 106.
  • the height of the protrusion 120 in the radial direction is approximately several ⁇ m.
  • This protrusion 120 is generated due to partial wear occurring on the inclined surface 202a of the grindstone 200. That is, the area near the boundary B has the largest amount of polishing, and the applied load and surface pressure are greater than in other areas. Therefore, wear becomes noticeable in the portion of the inclined surface 202a corresponding to the boundary B. Such partial wear on the inclined surface 202a causes a protrusion 120 near the boundary B.
  • the protrusions 120 come into contact with the bearing ring. Contact between the protrusion 120 and the raceway may reduce the life of the bearing. Further, the protrusion 120 is inevitably generated when the crowning portion 106 is formed by polishing. Therefore, even if the above-mentioned protrusion occurs, a measure is desired to suppress the reduction in bearing life.
  • This embodiment is a method for manufacturing bearing rollers.
  • the outer circumferential surface of the rough-formed product of the bearing roller includes a first rough-formed product chamfer and a surface to be polished, which are arranged in order from the first side to the second side in the axial direction of the rough-formed product.
  • the outer circumferential surface of the bearing roller includes a first chamfered portion, a first crowning portion, and a second crowning portion that are arranged in order from the first side to the second side in the axial direction of the bearing roller.
  • a grindstone is brought into contact with the surface to be polished, and the first crowning part and the second crowning part are removed from the surface while leaving the first chamfered part as the first chamfered part.
  • the method includes a polishing step of forming the bearing roller on a polished surface and obtaining the bearing roller from the rough-shaped product.
  • the grinding wheel has a contact surface that contacts the rough article and a first non-contact surface that is adjacent to the contact surface on the first side of the rough article.
  • the contact surface has a first inclined surface adjacent to the first non-contact surface and for forming the first crowning part, and a second inclined surface for forming the second crowning part.
  • a boundary between the first non-contact surface and the first sloped surface is a first boundary circle, a virtual plane including the first boundary circle is a first boundary surface, and the first slope and the second slope Let the boundary be the second boundary circle.
  • a tangent to the second inclined surface on the second boundary circle is a first tangent
  • the second inclined surface is a first tangent in the axial direction than the second boundary circle.
  • a first intersection where the first boundary surface and the first conical surface intersect, when the virtual conical surface extending toward the side and whose generating line is along the first tangent line is the first conical surface.
  • the difference between the radius of the circle and the radius of the first boundary circle is 3 ⁇ m or more and 20 ⁇ m or less.
  • rollers for bearings that can suppress reduction in bearing life.
  • FIG. 1 is a front view of a cylindrical roller.
  • FIG. 2A is an enlarged view of the main part of FIG.
  • FIG. 2B is a further enlarged view of the main part of FIG. 2A.
  • FIG. 3 is a diagram showing a method for manufacturing a cylindrical roller.
  • FIG. 4 is a diagram showing a cross section of the grindstone.
  • FIG. 5 is a diagram showing a cross section of the grindstone.
  • FIG. 6 is a cross-sectional view of a cylindrical roller bearing in which the cylindrical rollers of this embodiment are used.
  • FIG. 7A is a diagram showing a main part of the outer circumferential surface of a conventional bearing roller.
  • FIG. 7B is a diagram showing a grindstone used for a conventional bearing roller.
  • This embodiment is a method for manufacturing bearing rollers.
  • the outer circumferential surface of the rough-formed product of the bearing roller includes a first rough-formed product chamfer and a surface to be polished, which are arranged in order from the first side to the second side in the axial direction of the rough-formed product.
  • the outer circumferential surface of the bearing roller includes a first chamfered portion, a first crowning portion, and a second crowning portion that are arranged in order from the first side to the second side in the axial direction of the bearing roller.
  • the method includes a polishing step of forming the bearing roller on a polished surface and obtaining the bearing roller from the rough-shaped product.
  • the grinding wheel has a contact surface that contacts the rough article and a first non-contact surface that is adjacent to the contact surface on the first side of the rough article.
  • the contact surface has a first inclined surface adjacent to the first non-contact surface and for forming the first crowning part, and a second inclined surface for forming the second crowning part.
  • a boundary between the first non-contact surface and the first sloped surface is a first boundary circle
  • a virtual plane including the first boundary circle is a first boundary surface
  • the first slope and the second slope Let the boundary be the second boundary circle.
  • a tangent to the second inclined surface on the second boundary circle is a first tangent
  • the second inclined surface is a first tangent in the axial direction than the second boundary circle.
  • a first intersection where the first boundary surface and the first conical surface intersect, when the virtual conical surface extending toward the side and whose generating line is along the first tangent line is the first conical surface.
  • the difference between the radius of the circle and the radius of the first boundary circle is 3 ⁇ m or more and 20 ⁇ m or less.
  • the radial position of the boundary between the first chamfered portion and the first crowning portion of the bearing roller obtained by the above manufacturing method is the same as that of the first chamfered portion when only the second crowning portion is provided on the outer peripheral surface of the bearing roller. It is closer to the center axis of the bearing roller than the radial position of the boundary with the second crowning part.
  • the bearing roller obtained by the above embodiment has a diameter smaller than the virtual extension surface of the second crowning part. This can prevent the protrusion from contacting the bearing ring and shortening the life of the bearing.
  • the protrusion may protrude radially outward beyond the virtual extension surface of the second crowning portion. Further, if the difference between the radius of the first intersecting circle and the radius of the first boundary circle is larger than 20 ⁇ m, the amount of polishing of the surface to be polished becomes larger than necessary. An increase in the amount of polishing may lead to an increase in cost. In the above manufacturing method, by setting the difference between the radius of the first intersecting circle and the radius of the first boundary circle to 3 ⁇ m or more and 20 ⁇ m or less, it is possible to obtain a bearing roller that can suppress a decrease in bearing life.
  • the outer circumferential surface of the rough-formed product of the bearing roller further includes a second rough-formed product chamfered portion adjacent to the second side in the axial direction of the surface to be polished.
  • the outer circumferential surface of the bearing roller includes a second chamfered portion, a third crowning portion, and a third crowning portion arranged in order from the second side to the first side in the axial direction of the bearing roller.
  • the difference between the radius of the second intersecting circle and the radius of the third boundary circle is less than 3 ⁇ m, the protrusion that occurs near the boundary between the second chamfer and the third crowning part has a diameter larger than that of the virtual extension surface of the fourth crowning part. There is a risk of it protruding outward. Further, if the difference between the radius of the second intersecting circle and the radius of the third boundary circle is larger than 20 ⁇ m, the amount of polishing of the surface to be polished becomes larger than necessary. An increase in the amount of polishing may lead to an increase in cost. In the above manufacturing method, by setting the difference between the radius of the second intersecting circle and the radius of the third boundary circle to 3 ⁇ m or more and 20 ⁇ m or less, it is possible to more reliably obtain bearing rollers that can suppress reduction in bearing life. can.
  • Setting the ratio of the first spacing to the second spacing to be smaller than 1/20 may lead to the inability to secure the desired axial length of the first crowning portion, depending on the diameter of the bearing rollers. .
  • Making the ratio of the first interval to the second interval larger than 1/2 leads to the desired length of the first crowning portion in the axial direction becoming larger than necessary, and the amount of polishing increases. An increase in the amount of polishing may lead to an increase in cost.
  • Setting the ratio of the first interval to the second interval to be 1/20 or more and 1/2 or less allows the first crowning portion to be provided in a suitable range in the axial direction.
  • FIG. 1 is a front view of a cylindrical roller.
  • cylindrical rollers 1 are bearing rollers, and are used as rolling elements of cylindrical roller bearings and thrust roller bearings.
  • the cylindrical roller 1 is a cylindrical member made of bearing steel or the like.
  • the axial direction also includes a direction parallel to the central axis C1 of the cylindrical roller 1. Further, the direction along the diameter of the cylindrical roller 1 is referred to as the "radial direction”.
  • FIG. 2A is an enlarged view of the main part of FIG. FIG. 2A shows an end portion of the cylindrical roller 1 including the first roller end surface 1b.
  • the first chamfered portion 2 As shown in FIG. 2A, on the outer peripheral surface 1a of the cylindrical roller 1, the first chamfered portion 2, the first crowned portion 10, the second crowned portion 12, and the cylindrical portion 14 are arranged on the first roller end surface 1b ( The rollers are arranged in order along the axial direction from the first roller end face 1c (first side) to the second roller end face 1c (second side).
  • the first crowning part 10 is connected to the first chamfered part 2.
  • the second crowning part 12 is provided between the first crowning part 10 and the cylindrical part 14.
  • the second crowning part 12 is located on the opposite side of the central axis C1 of the cylindrical roller 1 from a virtual straight line connecting any two points on the cross-sectional contour line of the second crowning part 12 in a cross section including the central axis C1 of the cylindrical roller 1.
  • the second crowning portion 12 has a circular shape in an arbitrary plane perpendicular to the central axis C1 of the cylindrical roller 1.
  • the angle formed by the tangent at any position of the first crowning part 10 and the central axis C1 of the cylindrical roller 1 is equal to any angle of the second crowning part 12 excluding the boundary circle K2. It is larger than the angle between the tangent at the position and the central axis C1 of the cylindrical roller 1.
  • FIG. 2B is a further enlarged view of the main part of FIG. 2A.
  • the angle between the tangent at any position of the first crowning portion 10 and the central axis C1 of the cylindrical roller 1 is the same as that of the second crowning excluding the boundary circle K2. It is larger than the angle between the tangent at any position of the portion 12 and the central axis C1 of the cylindrical roller 1. Therefore, the first crowning part 10 is inclined so as to gradually move away from the first roller extended conical surface E1 as it goes from the second crowning part 12 to the first chamfered part 2.
  • the intersecting circle P1 is a circle where the first roller extension conical surface E1 and the first boundary surface L1 intersect.
  • the first boundary surface L1 is a virtual plane including the boundary circle K1.
  • the intersection circle P1 is a virtual boundary between the first chamfered part 2 and the second crowned part 12 when it is assumed that the first chamfered part 2 and the second crowned part 12 are connected without providing the first crowned part 10. It is a yen.
  • the difference D1 between the radius of the boundary circle K1 and the radius of the intersecting circle P1 is set to be 3 ⁇ m or more and 20 ⁇ m or less.
  • the third crowning part 16 and the fourth crowning part 18 have the same configuration as the first crowning part 10 and the second crowning part 12 which are reversed by 180 degrees with respect to the center in the axial direction.
  • FIG. 3 is a diagram showing a method of manufacturing the cylindrical roller 1.
  • FIG. 3 shows a polishing process for obtaining the cylindrical roller 1 from the rough-shaped product 20.
  • the rough-shaped product 20 is the material of the cylindrical roller 1.
  • the rough-shaped product 20 becomes the cylindrical roller 1 by providing the crowning parts 10, 12, 16, 18 and the cylindrical part 14.
  • the rough-shaped product 20 has an outer peripheral surface 20a, a first rough-shaped product end face 20b that is the first side of the coarse-shaped product in the axial direction, and a second rough-shaped product end face that is the second side of the coarse-shaped product in the axial direction. 20c.
  • the grindstone 30 is brought into contact with the surface to be polished 24 .
  • each crowning part 10, 12, 16, 18 and the cylindrical part 14 are provided on the surface to be polished 24.
  • the whetstone 30 is, for example, a whetstone using abrasive grains containing alumina as a main component.
  • the grindstone 30 is formed into a substantially cylindrical shape.
  • the grindstone 30 is rotatable around the central axis C2 of the grindstone 30 by a rotating device (not shown).
  • the contact surface 32b has a plurality of surfaces for forming each crowning portion 10, 12, 16, 18 and the cylindrical portion 14.
  • the surface to be polished 24 is polished by the contact surface 32b.
  • the shape of the contact surface 32b is transferred to the surface to be polished 24.
  • each crowning part 10, 12, 16, 18 and the cylindrical part 14 are formed on the surface to be polished 24.
  • the rough-shaped product 20 becomes the cylindrical roller 1 by forming the crowning parts 10, 12, 16, 18 and the cylindrical part 14 on the surface to be polished 24.
  • FIG. 4 is a diagram showing a cross section of the grindstone 30. Note that although FIG. 4 shows a cross section, the following description will mainly describe each part of the external shape that appears in the cross section.
  • the contact surface 32b has a first inclined surface 40, a second inclined surface 42, and a cylindrical surface (flat surface) 44.
  • the first inclined surface 40, the second inclined surface 42, and the cylindrical surface 44 extend from the first grinding wheel end surface 30a (first side) of the grinding wheel 30 to the second grinding wheel end surface 30b (second side) (Fig. 3) are lined up in order along the axial direction.
  • the cylindrical surface 44 is a surface for forming the cylindrical portion 14.
  • the cylindrical surface 44 is provided at the axial center of the contact surface 32b.
  • the first inclined surface 40 and the second inclined surface 42 are provided between the first non-contact surface 32a and the cylindrical surface 44.
  • the first inclined surface 40 is connected to the first non-contact surface 32a.
  • the first inclined surface 40 is a surface for forming the first crowning part 10.
  • the first inclined surface 40 has a curved surface.
  • the first inclined surface 40 has two arbitrary points on the central axis C2 side of the grinding wheel 30 from a virtual straight line connecting arbitrary two points on the cross-sectional contour line of the first inclined surface 40 in a cross section including the central axis C2 of the grinding wheel 30.
  • the first inclined surface 40 has a circular shape in any cross section perpendicular to the central axis C2 of the grindstone 30.
  • the second inclined line portion PL2 is a curved line having the same curvature as the curvature of the curved line in the cross section including the central axis C1 of the second crowning portion 12.
  • the straight line portion PL5 is a contour line corresponding to the cylindrical surface 44.
  • the straight line portion PL5 is a straight line parallel to the central axis C2.
  • the first boundary circle B1 is the boundary between the first non-contact surface 32a and the first inclined surface 40.
  • the first boundary circle B1 is in contact with the boundary circle K1 between the first chamfered part 2 and the first crowning part 10.
  • the second boundary circle B2 is the boundary between the first inclined surface 40 and the second inclined surface 42.
  • the second boundary circle B2 touches the boundary circle K2 between the first crowning part 10 and the second crowning part 12.
  • the first boundary surface L1 is a virtual plane including the first boundary circle B1 (boundary circle K1). Therefore, when the boundary circle K1 and the first boundary circle B1 coincide at the end of the polishing process, the first roller extension conical surface E1 and the first conical surface E10 overlap.
  • the first intersecting circle P10 is a circle where the first boundary surface L1 and the first conical surface E10 intersect.
  • the difference D10 between the radius of the first intersecting circle P10 and the radius of the first boundary circle B1 is 3 ⁇ m or more and 20 ⁇ m or less.
  • the radial position of the boundary circle K1 of the cylindrical roller 1 obtained by the above configuration is the difference between the first chamfered part 2 and the second crowned part 12 when only the second crowned part 12 is provided on the outer peripheral surface 1a of the cylindrical roller 1. It is closer to the center axis C1 of the cylindrical roller 1 than the radial position of the boundary (crossing circle P1).
  • the first roller can be placed radially inward from the extended conical surface E1 (FIG.
  • the lower limit of the difference D10 is preferably 5 ⁇ m or more. By setting the lower limit to 5 ⁇ m or more, the manufacturing method described above can more reliably accommodate the protrusion that occurs near the boundary circle K1 on the radially inward side of the first roller extension conical surface E1. Further, the upper limit of the difference D10 is preferably 10 ⁇ m or less. By setting the upper limit to 10 ⁇ m or less, the above manufacturing method can reliably suppress an increase in cost.
  • the distance in the axial direction between the second boundary circle B2 and the first boundary circle B1 is the first interval W1
  • the distance between the boundary circle B10 and the first boundary circle B1 is When the distance in the axial direction is defined as the second interval W2, the ratio of the first interval W1 to the second interval W2 is preferably 1/20 or more and 1/2 or less.
  • the boundary circle B10 (fifth boundary circle) is the boundary between the second inclined surface 42 and the cylindrical surface 44.
  • the first crowning part 10 formed by the first inclined surface 40 may have a narrower axial range. If the first crowning part 10 becomes smaller, there is a possibility that the necessary range for the first crowning part 10 cannot be secured. If the ratio of the first interval to the second interval is larger than 1/2, the first crowning portion 10 formed by the first inclined surface 40 will have a larger axial range than necessary, and the amount of polishing will increase. This may lead to an increase in costs.
  • the ratio of the first interval W1 to the second interval W2 can be 1/20 or more and 1/2 or less, the above manufacturing method can provide the first crowning portion 10 in a suitable axial range.
  • the lower limit of the ratio of the first interval W1 to the second interval W2 is preferably 1/7 or more.
  • the manufacturing method described above can more reliably provide the first crowning portion 10 in a suitable axial range.
  • the axial width of the first crowning part 10 of the cylindrical roller 1 formed by the grindstone 30 is the first crowning width CW1, and the entire crowning part including the first crowning part 10 and the second crowning part 12
  • the first crowning width CW1 relative to the overall crowning width CW can be set as follows. That is, when the overall crowning width CW is 1.5 mm or more and less than 3 mm, it is preferable that the first crowning width CW1 is 0.5 mm. Further, when the overall crowning width CW is 3 mm or more and less than 6 mm, it is preferable that the first crowning width CW1 is 1.0 mm. Further, when the overall crowning width CW is 6 mm or more, it is preferable that the first crowning width CW1 is 2 mm.
  • FIG. 5 is a diagram showing a cross section of the grindstone 30.
  • FIG. 5 shows a cross section of the grindstone 30 including the second grindstone end surface 30b. Note that although FIG. 5 shows a cross section, the following description will mainly describe each part of the external shape that appears in the cross section.
  • the outer circumferential surface 1a of the cylindrical roller 1 has the second chamfered portion 6, the third crowned portion 16, and the fourth crowned portion 18.
  • the second chamfered portion 6, the third crowned portion 16, and the fourth crowned portion 18 extend in the axial direction from the second roller end surface 1c (second side) of the cylindrical roller 1 toward the first roller end surface 1b (first side). are lined up in order along.
  • the third crowning portion 16 is connected to the second chamfered portion 6.
  • the fourth crowning part 18 is provided between the third crowning part 16 and the cylindrical part 14.
  • the third crowning part 16 has a similar shape to the first crowning part 10.
  • the fourth crowning part 18 has a similar shape to the second crowning part 12. Therefore, description of the third crowning part 16 and the fourth crowning part 18 will be omitted.
  • the contact surface 32b further includes a third inclined surface 50 and a fourth inclined surface 52.
  • the third inclined surface 50, the fourth inclined surface 52, and the cylindrical surface 44 are connected from the second grinding wheel end surface 30b (second side) of the grinding wheel 30 to the first grinding wheel end surface 30a (first side) (Fig. 3) are lined up in order along the axial direction.
  • the third inclined surface 50 and the fourth inclined surface 52 are provided between the second non-contact surface 32c and the cylindrical surface 44.
  • the third inclined surface 50 is connected to the second non-contact surface 32c.
  • the third inclined surface 50 is a surface for forming the third crowning portion 16.
  • the third inclined surface 50 has a curved surface.
  • the third boundary circle B3 is the boundary between the second non-contact surface 32c and the third inclined surface 50.
  • the third boundary circle B3 touches the boundary circle K4 between the second chamfered portion 6 and the third crowning portion 16.
  • the fourth boundary circle B4 is the boundary between the third inclined surface 50 and the fourth inclined surface 52.
  • the fourth boundary circle B4 touches the boundary circle K5 between the third crowning part 16 and the fourth crowning part 18.
  • the second boundary surface L2 is a virtual plane including the third boundary circle B3 (boundary circle K4). Therefore, when the boundary circle K4 and the third boundary circle B3 coincide at the end of the polishing process, the second roller extended conical surface E2 and the second virtual extended conical surface E12 overlap.
  • the second roller extended conical surface E2 is a virtual conical surface whose generatrix is a tangent to the fourth crowning portion 18 in the boundary circle K5 in a cross section including the central axis C1 of the cylindrical roller 1.
  • the second roller extension conical surface E2 is a virtual extension surface of the fourth crowning portion 18.
  • the second intersecting circle P12 is a circle where the second boundary surface L2 and the second conical surface E12 intersect.
  • the embodiments disclosed herein are illustrative in all respects and are not restrictive.
  • the first crowning part 10 and the third crowning part 16 are convex curved surfaces having a predetermined curvature, and the first inclined line part PL1 and the third inclined line part PL3 of the contour line PL of the grindstone 30 are , the curves correspond to the first crowning part 10 and the third crowning part 16.
  • the first crowning part 10 and the third crowning part 16 may be conical surfaces, and the first inclined line part PL1 and the third inclined line part PL3 may be straight lines.
  • the second crowning part 12 and the fourth crowning part 18 are convex curved surfaces having a predetermined curvature, and the second slope line part PL2 and the fourth slope line part PL4 of the contour line PL of the grindstone 30 are , the curves correspond to the second crowning part 12 and the fourth crowning part 18.
  • the second crowning part 12 and the fourth crowning part 18 may be conical surfaces, and the second inclined line part PL2 and the fourth inclined line part PL4 may be straight lines.
  • rollers used in cylindrical roller bearings
  • the method for manufacturing rollers disclosed in this embodiment is applicable to rollers other than cylindrical rollers, such as tapered rollers, bar rollers, needle rollers, etc. It is also applicable.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Rolling Contact Bearings (AREA)

Abstract

The method of manufacturing rollers for bearings of the present disclosure includes a polishing step of forming a first crowning part 10 and a second crowning part 12 by bringing a contact surface 32b of a grindstone 30 into contact with a to-be-polished surface 24 of a semifinished product 20 of a cylindrical roller 1 and polishing the to-be-polished surface 24. The contact surface 32b has a first inclined surface 40 and a second inclined surface 42. The difference between the radius of a first intersecting circle P10 where a first boundary surface L1 and a first conical surface E10 intersect and the radius of a first boundary circle B1 is 3 to 20 μm inclusive, where the first boundary circle is the boundary between a first non-contact surface and the first inclined surface, the first boundary surface is a virtual plane including the first boundary circle, a second boundary circle is the boundary between the first inclined surface and the second inclined surface, a first tangent E110 is a tangent to the second inclined surface 42 on the second boundary circle B2 in a cross section including the center axis C2 of the grindstone 30, and the first conical surface E10 is a virtual conical surface which is an extension of the second inclined surface 42 and of which the generating line is along the first tangent E110.

Description

軸受用ころの製造方法Manufacturing method of rollers for bearings
　本発明は、軸受用ころの製造方法に関する。 The present invention relates to a method for manufacturing bearing rollers.
　軸受用ころの外径面は、軸方向端部に生じる過度な応力負荷を緩和するためにクラウニングが設けられることがある。クラウニングは、外径面の母線の全域又は軸方向両端部に僅かな曲率又は傾斜を設けることである（例えば、特許文献１参照）。 The outer diameter surface of the bearing roller is sometimes provided with a crowning in order to relieve the excessive stress load that occurs at the axial end. Crowning is to provide a slight curvature or inclination to the entire region of the generatrix of the outer diameter surface or to both ends in the axial direction (see, for example, Patent Document 1).
特開２００５－１５５７６３号公報Japanese Patent Application Publication No. 2005-155763
　図７Ａは、従来の軸受用ころの外周面の要部を示す図である。
　図７Ａ中、軸受用ころ１００の外周面１００ａは、軸受用ころ１００の第１側１００ｂから軸方向に沿って順番に並ぶ、面取り部１０２と、外径面１０４とを有する。
　外径面１０４は、面取り部１０２に隣接するクラウニング部１０６と、クラウニング部１０６に繋がっている円筒部１０８とを有する。
　クラウニング部１０６は、所定の曲率を有しており、面取り部１０２と円筒部１０８とを滑らかに繋いでいる。 FIG. 7A is a diagram showing a main part of the outer circumferential surface of a conventional bearing roller.
In FIG. 7A, the outer circumferential surface 100a of the bearing roller 100 has a chamfered portion 102 and an outer diameter surface 104, which are arranged in order along the axial direction from the first side 100b of the bearing roller 100.
The outer diameter surface 104 has a crowning portion 106 adjacent to the chamfered portion 102 and a cylindrical portion 108 connected to the crowning portion 106.
The crowning part 106 has a predetermined curvature and smoothly connects the chamfered part 102 and the cylindrical part 108.
　クラウニング部１０６は、図７Ｂに示すように、粗形品１１０の外周面１１０ａに砥石２００の加工面２０２を接触させて研磨することで形成される。粗形品１１０は、軸受用ころ１００の素材であり、クラウニング部１０６及び円筒部１０８を設けることで軸受用ころ１００になる。粗形品１１０の外周面１１０ａは、面取り部１１２と、被研磨面１１４とを有する。面取り部１１２は軸受用ころ１００の面取り部１０２として残される。 As shown in FIG. 7B, the crowning portion 106 is formed by bringing the processed surface 202 of the grindstone 200 into contact with the outer circumferential surface 110a of the rough-shaped product 110 and polishing it. The roughly shaped product 110 is a raw material for the bearing roller 100, and becomes the bearing roller 100 by providing the crowning portion 106 and the cylindrical portion 108. The outer peripheral surface 110a of the rough-shaped product 110 has a chamfered portion 112 and a surface to be polished 114. The chamfered portion 112 remains as the chamfered portion 102 of the bearing roller 100.
　加工面２０２は、クラウニング部１０６を形成するための傾斜面２０２ａと、円筒部１０８を形成するための円筒面２０２ｂとを有している。両面２０２ａ，２０２ｂは、クラウニング部１０６及び円筒部１０８の形状と合致する形状に形成（ドレッシング）される。 The processed surface 202 has an inclined surface 202a for forming the crowning portion 106 and a cylindrical surface 202b for forming the cylindrical portion 108. Both surfaces 202a and 202b are formed (dressed) into a shape that matches the shapes of the crowning part 106 and the cylindrical part 108.
　ドレッシングされた砥石２００は、軸受用ころ１００の研磨に繰り返し使用される。
　砥石２００の両面２０２ａ，２０２ｂは、繰り返し使用されることで摩耗によって徐々に変形する。この変形により、形成されるクラウニング部１０６の寸法精度も徐々に低下する。このため、砥石２００は、所定の繰り返し回数だけ使用された後に、再度ドレッシングされ、クラウニング部１０６及び円筒部１０８の形状と合致する形状に再形成される。 The dressed grindstone 200 is repeatedly used to polish the bearing rollers 100.
Both surfaces 202a and 202b of the grindstone 200 gradually deform due to wear due to repeated use. Due to this deformation, the dimensional accuracy of the crowning portion 106 that is formed also gradually decreases. Therefore, after the grindstone 200 has been used a predetermined number of times, it is dressed again and reshaped into a shape that matches the shapes of the crowning part 106 and the cylindrical part 108.
　ここで、軸受用ころ１００が砥石２００によって研磨されたとき、図７Ａの破線の円中に示す部分断面図で示すように、突起１２０が研磨後の軸受用ころ１００における面取り部１０２と、クラウニング部１０６との境界Ｂの近傍に生じることがある。突起１２０の径方向の高さは数μｍ程度である。
　この突起１２０は、砥石２００の傾斜面２０２ａに生じる部分的な摩耗に起因して発生する。すなわち、境界Ｂの近傍は、最も研磨量が多く、作用する負荷及び面圧が他の部分と比較して大きい。このため、摩耗は、傾斜面２０２ａにおける境界Ｂに対応する部分で顕著になる。このような傾斜面２０２ａにおける部分的な摩耗は、境界Ｂの近傍に突起１２０を引き起こす。 Here, when the bearing roller 100 is polished by the grindstone 200, as shown in the partial cross-sectional view shown in the broken line circle in FIG. This may occur near the boundary B with the section 106. The height of the protrusion 120 in the radial direction is approximately several μm.
This protrusion 120 is generated due to partial wear occurring on the inclined surface 202a of the grindstone 200. That is, the area near the boundary B has the largest amount of polishing, and the applied load and surface pressure are greater than in other areas. Therefore, wear becomes noticeable in the portion of the inclined surface 202a corresponding to the boundary B. Such partial wear on the inclined surface 202a causes a protrusion 120 near the boundary B.
　軸受用ころ１００が軸受に用いられたとき、突起１２０は、軌道輪と接触する。突起１２０と軌道との接触は、軸受の寿命を低下させるおそれがある。
　また、突起１２０は、研磨によってクラウニング部１０６を形成する上において不可避的に発生する。
　このため、上述の突起が生じたとしても、軸受寿命低下を抑制する方策が望まれる。 When the bearing rollers 100 are used in a bearing, the protrusions 120 come into contact with the bearing ring. Contact between the protrusion 120 and the raceway may reduce the life of the bearing.
Further, the protrusion 120 is inevitably generated when the crowning portion 106 is formed by polishing.
Therefore, even if the above-mentioned protrusion occurs, a measure is desired to suppress the reduction in bearing life.
　本実施形態は、軸受用ころの製造方法である。前記軸受用ころの粗形品の外周面は、前記粗形品の軸方向の第１側から第２側へ向かって順番に並ぶ、第１粗形品面取り部と、被研磨面と、を有する。前記軸受用ころの外周面は、前記軸受用ころの軸方向の第１側から第２側へ向かって順番に並ぶ、第１面取り部と、第１クラウニング部と、第２クラウニング部と、を有する。この製造方法は、前記被研磨面に対して砥石を接触させ、前記第１粗形品面取り部を前記第１面取り部として残しつつ、前記第１クラウニング部、及び前記第２クラウニング部を前記被研磨面に形成し、前記粗形品から前記軸受用ころを得る研磨工程を含む。前記砥石は、前記粗形品に接触する接触面と、前記粗形品の前記第１側で前記接触面に隣接する第１非接触面と、を有する。前記接触面は、前記第１非接触面に隣接するとともに前記第１クラウニング部を形成するための第１傾斜面と、前記第２クラウニング部を形成するための第２傾斜面と、を有する。前記第１非接触面と前記第１傾斜面との境界を第１境界円とし、前記第１境界円を含む仮想平面を第１境界面とし、前記第１傾斜面と前記第２傾斜面との境界を第２境界円とする。また、前記砥石の中心軸を含む断面において、前記第２境界円上の前記第２傾斜面に対する接線を第１接線とし、前記第２傾斜面を前記第２境界円よりも軸方向の第１側へ延長した仮想円すい面であって母線が前記第１接線に沿う前記仮想円すい面を、第１円すい面としたとき、前記第１境界面と前記第１円すい面とが交差する第１交差円の半径と、前記第１境界円の半径と、の差が３μｍ以上、２０μｍ以下である。 This embodiment is a method for manufacturing bearing rollers. The outer circumferential surface of the rough-formed product of the bearing roller includes a first rough-formed product chamfer and a surface to be polished, which are arranged in order from the first side to the second side in the axial direction of the rough-formed product. have The outer circumferential surface of the bearing roller includes a first chamfered portion, a first crowning portion, and a second crowning portion that are arranged in order from the first side to the second side in the axial direction of the bearing roller. have In this manufacturing method, a grindstone is brought into contact with the surface to be polished, and the first crowning part and the second crowning part are removed from the surface while leaving the first chamfered part as the first chamfered part. The method includes a polishing step of forming the bearing roller on a polished surface and obtaining the bearing roller from the rough-shaped product. The grinding wheel has a contact surface that contacts the rough article and a first non-contact surface that is adjacent to the contact surface on the first side of the rough article. The contact surface has a first inclined surface adjacent to the first non-contact surface and for forming the first crowning part, and a second inclined surface for forming the second crowning part. A boundary between the first non-contact surface and the first sloped surface is a first boundary circle, a virtual plane including the first boundary circle is a first boundary surface, and the first slope and the second slope Let the boundary be the second boundary circle. Further, in a cross section including the central axis of the grindstone, a tangent to the second inclined surface on the second boundary circle is a first tangent, and the second inclined surface is a first tangent in the axial direction than the second boundary circle. A first intersection where the first boundary surface and the first conical surface intersect, when the virtual conical surface extending toward the side and whose generating line is along the first tangent line is the first conical surface. The difference between the radius of the circle and the radius of the first boundary circle is 3 μm or more and 20 μm or less.
　本開示によれば、軸受寿命低下の抑制が可能な軸受用ころを得ることができる。 According to the present disclosure, it is possible to obtain rollers for bearings that can suppress reduction in bearing life.
図１は、円筒ころの正面図である。FIG. 1 is a front view of a cylindrical roller. 図２Ａは、図１の要部拡大図である。FIG. 2A is an enlarged view of the main part of FIG. 図２Ｂは、図２Ａの要部をさらに拡大した図である。FIG. 2B is a further enlarged view of the main part of FIG. 2A. 図３は、円筒ころの製造方法を示す図である。FIG. 3 is a diagram showing a method for manufacturing a cylindrical roller. 図４は、砥石の断面を示す図である。FIG. 4 is a diagram showing a cross section of the grindstone. 図５は、砥石の断面を示す図である。FIG. 5 is a diagram showing a cross section of the grindstone. 図６は、本実施形態の円筒ころが用いられる円筒ころ軸受の断面図である。FIG. 6 is a cross-sectional view of a cylindrical roller bearing in which the cylindrical rollers of this embodiment are used. 図７Ａは、従来の軸受用ころの外周面の要部を示す図である。FIG. 7A is a diagram showing a main part of the outer circumferential surface of a conventional bearing roller. 図７Ｂは、従来の軸受用ころに用いられる砥石を示す図である。FIG. 7B is a diagram showing a grindstone used for a conventional bearing roller.
　最初に実施形態の内容を列記して説明する。
［実施形態の概要］
（１）本実施形態は、軸受用ころの製造方法である。前記軸受用ころの粗形品の外周面は、前記粗形品の軸方向の第１側から第２側へ向かって順番に並ぶ、第１粗形品面取り部と、被研磨面と、を有する。前記軸受用ころの外周面は、前記軸受用ころの軸方向の第１側から第２側へ向かって順番に並ぶ、第１面取り部と、第１クラウニング部と、第２クラウニング部と、を有する。この製造方法は、前記被研磨面に対して砥石を接触させ、前記第１粗形品面取り部を前記第１面取り部として残しつつ、前記第１クラウニング部、及び前記第２クラウニング部を前記被研磨面に形成し、前記粗形品から前記軸受用ころを得る研磨工程を含む。前記砥石は、前記粗形品に接触する接触面と、前記粗形品の前記第１側で前記接触面に隣接する第１非接触面と、を有する。前記接触面は、前記第１非接触面に隣接するとともに前記第１クラウニング部を形成するための第１傾斜面と、前記第２クラウニング部を形成するための第２傾斜面と、を有する。前記第１非接触面と前記第１傾斜面との境界を第１境界円とし、前記第１境界円を含む仮想平面を第１境界面とし、前記第１傾斜面と前記第２傾斜面との境界を第２境界円とする。また、前記砥石の中心軸を含む断面において、前記第２境界円上の前記第２傾斜面に対する接線を第１接線とし、前記第２傾斜面を前記第２境界円よりも軸方向の第１側へ延長した仮想円すい面であって母線が前記第１接線に沿う前記仮想円すい面を、第１円すい面としたとき、前記第１境界面と前記第１円すい面とが交差する第１交差円の半径と、前記第１境界円の半径と、の差が３μｍ以上、２０μｍ以下である。 First, the contents of the embodiment will be listed and explained.
[Overview of embodiment]
(1) This embodiment is a method for manufacturing bearing rollers. The outer circumferential surface of the rough-formed product of the bearing roller includes a first rough-formed product chamfer and a surface to be polished, which are arranged in order from the first side to the second side in the axial direction of the rough-formed product. have The outer circumferential surface of the bearing roller includes a first chamfered portion, a first crowning portion, and a second crowning portion that are arranged in order from the first side to the second side in the axial direction of the bearing roller. have In this manufacturing method, a grindstone is brought into contact with the surface to be polished, and the first crowning part and the second crowning part are removed from the surface while leaving the first chamfered part as the first chamfered part. The method includes a polishing step of forming the bearing roller on a polished surface and obtaining the bearing roller from the rough-shaped product. The grinding wheel has a contact surface that contacts the rough article and a first non-contact surface that is adjacent to the contact surface on the first side of the rough article. The contact surface has a first inclined surface adjacent to the first non-contact surface and for forming the first crowning part, and a second inclined surface for forming the second crowning part. A boundary between the first non-contact surface and the first sloped surface is a first boundary circle, a virtual plane including the first boundary circle is a first boundary surface, and the first slope and the second slope Let the boundary be the second boundary circle. Further, in a cross section including the central axis of the grindstone, a tangent to the second inclined surface on the second boundary circle is a first tangent, and the second inclined surface is a first tangent in the axial direction than the second boundary circle. A first intersection where the first boundary surface and the first conical surface intersect, when the virtual conical surface extending toward the side and whose generating line is along the first tangent line is the first conical surface. The difference between the radius of the circle and the radius of the first boundary circle is 3 μm or more and 20 μm or less.
　上記製造方法によって得られる軸受用ころの第１面取り部と第１クラウニング部との境界の径方向位置は、軸受用ころの外周面に第２クラウニング部のみを設けた場合における第１面取り部と第２クラウニング部との境界の径方向位置よりも軸受用ころの中心軸寄りになる。これにより、上記実施形態によって得られた軸受用ころは、第１面取り部と第１クラウニング部との境界近傍に突起が生じたとしても、この突起を第２クラウニング部の仮想延長面よりも径方向内方側に収めることができ、突起が軌道輪に接触して軸受の寿命を低下させるのを抑制することができる。
　第１交差円の半径と第１境界円の半径との差が３μｍより小さい場合、突起は第２クラウニング部の仮想延長面よりも径方向外方へ突出するおそれがある。また、第１交差円の半径と第１境界円の半径との差が２０μｍよりも大きい場合、被研磨面の研磨量は必要以上に大きくなる。研磨量の増大は、コスト増加に繋がるおそれがある。
　上記製造方法は、第１交差円の半径と第１境界円の半径との差を３μｍ以上、２０μｍ以下とすることで、軸受寿命低下の抑制が可能な軸受用ころを得ることができる。 The radial position of the boundary between the first chamfered portion and the first crowning portion of the bearing roller obtained by the above manufacturing method is the same as that of the first chamfered portion when only the second crowning portion is provided on the outer peripheral surface of the bearing roller. It is closer to the center axis of the bearing roller than the radial position of the boundary with the second crowning part. As a result, even if a protrusion is generated near the boundary between the first chamfered part and the first crowning part, the bearing roller obtained by the above embodiment has a diameter smaller than the virtual extension surface of the second crowning part. This can prevent the protrusion from contacting the bearing ring and shortening the life of the bearing.
If the difference between the radius of the first intersecting circle and the radius of the first boundary circle is smaller than 3 μm, the protrusion may protrude radially outward beyond the virtual extension surface of the second crowning portion. Further, if the difference between the radius of the first intersecting circle and the radius of the first boundary circle is larger than 20 μm, the amount of polishing of the surface to be polished becomes larger than necessary. An increase in the amount of polishing may lead to an increase in cost.
In the above manufacturing method, by setting the difference between the radius of the first intersecting circle and the radius of the first boundary circle to 3 μm or more and 20 μm or less, it is possible to obtain a bearing roller that can suppress a decrease in bearing life.
（２）上記軸受用ころの製造方法において、前記軸受用ころの粗形品の外周面は、前記被研磨面の軸方向の第２側に隣接する第２粗形品面取り部をさらに有し、前記軸受用ころの外周面は、前記軸受用ころの軸方向の第２側から第１側へ向かって順番に並ぶ、第２面取り部と、第３クラウニング部と、前記第３クラウニング部と前記平坦部との間に位置する第４クラウニング部と、を有し、前記研磨工程では、前記第２粗形品面取り部を前記第２面取り部として残しつつ、前記第１クラウニング部、及び前記第２クラウニング部に加えて、前記第３クラウニング部、及び前記第４クラウニング部を前記被研磨面に形成し、前記砥石は、前記粗形品の前記第２側で前記接触面に隣接する第２非接触面をさらに有し、前記接触面は、前記第２非接触面に隣接するとともに前記第３クラウニング部を形成するための第３傾斜面と、前記第４クラウニング部を形成するための第４傾斜面と、をさらに有し、前記第２非接触面と前記第３傾斜面との境界を第３境界円とし、前記第３境界円を含む仮想平面を第２境界面とし、前記第３傾斜面と前記第４傾斜面との境界を第４境界円とし、前記砥石の中心軸を含む断面において、前記第４境界円上の前記第４傾斜面に対する接線を第２接線とし、前記第４傾斜面を前記第４境界円よりも軸方向の第２側へ延長した仮想円すい面であって母線が前記第２接線に沿う前記仮想円すい面を、第２円すい面としたとき、前記第２境界面と前記第２円すい面とが交差する第２交差円の半径と、前記第３境界円の半径と、の差が３μｍ以上、２０μｍ以下であることが好ましい。
　第２交差円の半径と第３境界円の半径との差が３μｍより小さい場合、第２面取り部と第３クラウニング部との境界近傍に生じる突起は第４クラウニング部の仮想延長面よりも径方向外方へ突出するおそれがある。また、第２交差円の半径と第３境界円の半径との差が２０μｍよりも大きい場合、被研磨面の研磨量は必要以上に大きくなる。研磨量の増大はコスト増加に繋がるおそれがある。
　上記製造方法は、第２交差円の半径と第３境界円の半径との差を３μｍ以上、２０μｍ以下とすることで、軸受寿命低下の抑制が可能な軸受用ころをより確実に得ることができる。 (2) In the above method for manufacturing a bearing roller, the outer circumferential surface of the rough-formed product of the bearing roller further includes a second rough-formed product chamfered portion adjacent to the second side in the axial direction of the surface to be polished. , the outer circumferential surface of the bearing roller includes a second chamfered portion, a third crowning portion, and a third crowning portion arranged in order from the second side to the first side in the axial direction of the bearing roller. a fourth crowning part located between the flat part, and in the polishing step, while leaving the second rough-shaped product chamfer as the second chamfer, the first crowning part and the In addition to the second crowning portion, the third crowning portion and the fourth crowning portion are formed on the surface to be polished, and the grinding wheel has a second crowning portion adjacent to the contact surface on the second side of the rough-shaped article. The contact surface further includes a third inclined surface adjacent to the second non-contact surface and for forming the third crowning part, and a third inclined surface for forming the fourth crowning part. a fourth inclined surface, a boundary between the second non-contact surface and the third inclined surface is a third boundary circle, a virtual plane including the third boundary circle is a second boundary surface; The boundary between the third slope and the fourth slope is a fourth boundary circle, and in a cross section including the central axis of the grindstone, a tangent to the fourth slope on the fourth boundary circle is a second tangent, When the virtual conical surface is a virtual conical surface in which the fourth inclined surface is extended toward the second side in the axial direction from the fourth boundary circle, and the generating line is along the second tangent line, the virtual conical surface is a second conical surface, It is preferable that the difference between the radius of the second intersecting circle where the second boundary surface and the second conical surface intersect and the radius of the third boundary circle is 3 μm or more and 20 μm or less.
If the difference between the radius of the second intersecting circle and the radius of the third boundary circle is less than 3 μm, the protrusion that occurs near the boundary between the second chamfer and the third crowning part has a diameter larger than that of the virtual extension surface of the fourth crowning part. There is a risk of it protruding outward. Further, if the difference between the radius of the second intersecting circle and the radius of the third boundary circle is larger than 20 μm, the amount of polishing of the surface to be polished becomes larger than necessary. An increase in the amount of polishing may lead to an increase in cost.
In the above manufacturing method, by setting the difference between the radius of the second intersecting circle and the radius of the third boundary circle to 3 μm or more and 20 μm or less, it is possible to more reliably obtain bearing rollers that can suppress reduction in bearing life. can.
（３）上記軸受用ころの製造方法において、前記軸受用ころの外周面は、前記第２クラウニング部の前記軸受用ころの軸方向の第２側で前記第２クラウニング部に隣接する円筒部をさらに有し、前記接触面は、前記第２傾斜面に隣接するとともに前記円筒部を形成するための円筒面をさらに有し、前記第２傾斜面と前記円筒面との境界を第５境界円とし、
　前記第１境界円と前記第２境界円との間の軸方向の距離を第１間隔、前記第１境界円と前記第５境界円との軸方向の距離を第２間隔とするとき、前記第２間隔に対する前記第１間隔の割合は、１／２０以上、１／２以下であることが好ましい。
　第２間隔に対する第１間隔の割合を１／２０よりも小さくすることは、軸受用ころの径寸法によっては、第１クラウニング部の所望の軸方向の長さが確保できないことに繋がるおそれがある。第２間隔に対する第１間隔の割合を１／２よりも大きくすることは、第１クラウニング部の所望の軸方向の長さが必要以上に大きくなることに繋がり、研磨量が大きくなる。研磨量が大きくなることは、コストが増加することに繋がるおそれがある。
　第２間隔に対する第１間隔の割合を１／２０以上、１／２以下とすることは、軸方向における好適な範囲で第１クラウニング部を設けることを許容する。 (3) In the above method for manufacturing bearing rollers, the outer circumferential surface of the bearing rollers includes a cylindrical portion adjacent to the second crowning portion on the second side in the axial direction of the bearing rollers of the second crowning portion. The contact surface further includes a cylindrical surface adjacent to the second inclined surface and for forming the cylindrical portion, and the boundary between the second inclined surface and the cylindrical surface is defined by a fifth boundary circle. year,
When the axial distance between the first boundary circle and the second boundary circle is a first interval, and the axial distance between the first boundary circle and the fifth boundary circle is a second interval, The ratio of the first interval to the second interval is preferably 1/20 or more and 1/2 or less.
Setting the ratio of the first spacing to the second spacing to be smaller than 1/20 may lead to the inability to secure the desired axial length of the first crowning portion, depending on the diameter of the bearing rollers. . Making the ratio of the first interval to the second interval larger than 1/2 leads to the desired length of the first crowning portion in the axial direction becoming larger than necessary, and the amount of polishing increases. An increase in the amount of polishing may lead to an increase in cost.
Setting the ratio of the first interval to the second interval to be 1/20 or more and 1/2 or less allows the first crowning portion to be provided in a suitable range in the axial direction.
［実施形態の詳細］
　以下、好ましい実施形態について図面を参照しつつ説明する。
〔円筒ころの構成〕 [Details of embodiment]
Hereinafter, preferred embodiments will be described with reference to the drawings.
[Cylindrical roller configuration]
　図１は、円筒ころの正面図である。
　図１中、円筒ころ１は、軸受用ころであり、円筒ころ軸受やスラストころ軸受の転動体として用いられる。
　円筒ころ１は、軸受鋼等により形成された円筒状の部材である。
　以下の説明においては、円筒ころ１の中心軸Ｃ１に沿う方向を「軸方向」という。軸方向には、円筒ころ１の中心軸Ｃ１に平行な方向も含まれる。また、円筒ころ１の直径に沿う方向を「径方向」という。 FIG. 1 is a front view of a cylindrical roller.
In FIG. 1, cylindrical rollers 1 are bearing rollers, and are used as rolling elements of cylindrical roller bearings and thrust roller bearings.
The cylindrical roller 1 is a cylindrical member made of bearing steel or the like.
In the following description, the direction along the central axis C1 of the cylindrical roller 1 will be referred to as the "axial direction." The axial direction also includes a direction parallel to the central axis C1 of the cylindrical roller 1. Further, the direction along the diameter of the cylindrical roller 1 is referred to as the "radial direction".
　円筒ころ１は、外周面１ａと、円筒ころ１の軸方向の第１側である第１ころ端面１ｂと、円筒ころ１の軸方向の第２側である第２ころ端面１ｃと、を有する。
　円筒ころ１の外周面１ａは、第１面取り部２と、外径面４と、第２面取り部６とを有する。
　第１面取り部２は、円筒ころ１の第１ころ端面１ｂと、外径面４との間に設けられる。
　第２面取り部６は、円筒ころ１の第２ころ端面１ｃと、外径面４との間に設けられる。 The cylindrical roller 1 has an outer peripheral surface 1a, a first roller end surface 1b that is the first side of the cylindrical roller 1 in the axial direction, and a second roller end surface 1c that is the second side of the cylindrical roller 1 in the axial direction. .
The outer peripheral surface 1a of the cylindrical roller 1 has a first chamfered portion 2, an outer diameter surface 4, and a second chamfered portion 6.
The first chamfered portion 2 is provided between the first roller end surface 1b of the cylindrical roller 1 and the outer diameter surface 4.
The second chamfered portion 6 is provided between the second roller end surface 1c of the cylindrical roller 1 and the outer diameter surface 4.
　外径面４は、研磨された表面である。
　外径面４は、第１クラウニング部１０と、第２クラウニング部１２と、円筒部（平坦部）１４と、第３クラウニング部１６と、第４クラウニング部１８とを有する。
　外径面４は、転動面を含む。転動面は、円筒ころ１が組み込まれる円筒ころ軸受の内外輪の軌道面に接触する面である。転動面は、第２クラウニング部１２の全部と、円筒部１４の全部と、第４クラウニング部１８の全部と、第１クラウニング部１０の軸方向の第２側の一部と、第３クラウニング部１６の軸方向の第１側の一部と、を含む。 The outer diameter surface 4 is a polished surface.
The outer diameter surface 4 has a first crowning part 10 , a second crowning part 12 , a cylindrical part (flat part) 14 , a third crowning part 16 , and a fourth crowning part 18 .
The outer diameter surface 4 includes a rolling surface. The rolling surface is a surface that contacts the raceway surfaces of the inner and outer rings of the cylindrical roller bearing in which the cylindrical rollers 1 are incorporated. The rolling surface includes all of the second crowning part 12, all of the cylindrical part 14, all of the fourth crowning part 18, a part of the second side of the first crowning part 10 in the axial direction, and the third crowning part. A part of the first side of the portion 16 in the axial direction.
　円筒部１４は、外径面４の軸方向中央に設けられている。
　第１クラウニング部１０及び第２クラウニング部１２は、円筒部１４と第１面取り部２との間に設けられている。第１クラウニング部１０及び第２クラウニング部１２は、円筒部１４から第１面取り部２へ向かって縮径するように傾斜している傾斜面である。円筒ころ１の中心軸を含む断面において、第１クラウニング部１０及び第２クラウニング部１２は、円筒部１４に対して傾斜している。
　第３クラウニング部１６及び第４クラウニング部１８は、円筒部１４と第２面取り部６との間に設けられている。第３クラウニング部１６及び第４クラウニング部１８は、円筒部１４から第２面取り部６へ向かって縮径するように傾斜している傾斜面である。円筒ころ１の中心軸を含む断面において、第３クラウニング部１６及び第４クラウニング部１８は、円筒部１４に対して傾斜している。
　外径面４は、傾斜面である各クラウニング部１０，１２，１６，１８を有することで、全体としてクラウニング形状を有する。 The cylindrical portion 14 is provided at the center of the outer diameter surface 4 in the axial direction.
The first crowning part 10 and the second crowning part 12 are provided between the cylindrical part 14 and the first chamfered part 2. The first crowning part 10 and the second crowning part 12 are inclined surfaces whose diameters decrease from the cylindrical part 14 toward the first chamfered part 2. In the cross section including the central axis of the cylindrical roller 1, the first crowning part 10 and the second crowning part 12 are inclined with respect to the cylindrical part 14.
The third crowning part 16 and the fourth crowning part 18 are provided between the cylindrical part 14 and the second chamfered part 6. The third crowning part 16 and the fourth crowning part 18 are inclined surfaces whose diameters decrease from the cylindrical part 14 toward the second chamfered part 6. In the cross section including the central axis of the cylindrical roller 1, the third crowning part 16 and the fourth crowning part 18 are inclined with respect to the cylindrical part 14.
The outer diameter surface 4 has crowning portions 10, 12, 16, and 18 that are inclined surfaces, so that the outer diameter surface 4 has a crowned shape as a whole.
　図２Ａは、図１の要部拡大図である。図２Ａは、円筒ころ１の第１ころ端面１ｂを含む端部を示している。
　図２Ａに示すように、円筒ころ１の外周面１ａにおいて、第１面取り部２、第１クラウニング部１０、第２クラウニング部１２、及び円筒部１４は、円筒ころ１の第１ころ端面１ｂ（第１側）から第２ころ端面１ｃ（第２側）へ向かって軸方向に沿って順番に並んでいる。
　第１クラウニング部１０は、第１面取り部２に繋がっている。第２クラウニング部１２は、第１クラウニング部１０と円筒部１４との間に設けられている。
　第１面取り部２と第１クラウニング部１０との境界は、円筒ころ１の中心軸Ｃ１の周方向に延在する境界円Ｋ１である。
　第１クラウニング部１０と第２クラウニング部１２との境界は、円筒ころ１の中心軸Ｃ１の周方向に延在する境界円Ｋ２である。 FIG. 2A is an enlarged view of the main part of FIG. FIG. 2A shows an end portion of the cylindrical roller 1 including the first roller end surface 1b.
As shown in FIG. 2A, on the outer peripheral surface 1a of the cylindrical roller 1, the first chamfered portion 2, the first crowned portion 10, the second crowned portion 12, and the cylindrical portion 14 are arranged on the first roller end surface 1b ( The rollers are arranged in order along the axial direction from the first roller end face 1c (first side) to the second roller end face 1c (second side).
The first crowning part 10 is connected to the first chamfered part 2. The second crowning part 12 is provided between the first crowning part 10 and the cylindrical part 14.
The boundary between the first chamfered portion 2 and the first crowning portion 10 is a boundary circle K1 extending in the circumferential direction of the central axis C1 of the cylindrical roller 1.
The boundary between the first crowning part 10 and the second crowning part 12 is a boundary circle K2 extending in the circumferential direction of the central axis C1 of the cylindrical roller 1.
　第１クラウニング部１０及び第２クラウニング部１２は、上述したように、円筒部１４から第１面取り部２へ向かって縮径するように傾斜している。
　第１クラウニング部１０は曲面を有する。第１クラウニング部１０は、円筒ころ１の中心軸Ｃ１を含む断面において第１クラウニング部１０の断面輪郭線上の任意の２点を結ぶ仮想直線より円筒ころ１の中心軸Ｃ１とは反対側に任意の２点の間の断面輪郭線上の点が存在する所定の曲率を有する曲線を有する。第１クラウニング部１０は、円筒ころ１の中心軸Ｃ１に垂直な任意の平面において円形を有する。
　第２クラウニング部１２は曲面を有する。第２クラウニング部１２は、円筒ころ１の中心軸Ｃ１を含む断面において第２クラウニング部１２の断面輪郭線上の任意の２点を結ぶ仮想直線より円筒ころ１の中心軸Ｃ１とは反対側に任意の２点の間の断面輪郭線上の点が存在する所定の曲率を有する曲線を有する。第２クラウニング部１２は、円筒ころ１の中心軸Ｃ１に垂直な任意の平面において円形を有する。
　円筒ころ１の中心軸Ｃ１を含む断面において、第１クラウニング部１０の任意の位置での接線と円筒ころ１の中心軸Ｃ１と成す角度は、境界円Ｋ２を除く第２クラウニング部１２の任意の位置での接線と円筒ころ１の中心軸Ｃ１と成す角度よりも大きい。 As described above, the first crowning part 10 and the second crowning part 12 are inclined so that the diameter decreases from the cylindrical part 14 toward the first chamfered part 2.
The first crowning portion 10 has a curved surface. The first crowning part 10 is located on the opposite side of the central axis C1 of the cylindrical roller 1 from an imaginary straight line connecting any two points on the cross-sectional contour line of the first crowning part 10 in a cross section including the central axis C1 of the cylindrical roller 1. A point on the cross-sectional contour line between two points of exists a curve having a predetermined curvature. The first crowning portion 10 has a circular shape in an arbitrary plane perpendicular to the central axis C1 of the cylindrical roller 1.
The second crowning portion 12 has a curved surface. The second crowning part 12 is located on the opposite side of the central axis C1 of the cylindrical roller 1 from a virtual straight line connecting any two points on the cross-sectional contour line of the second crowning part 12 in a cross section including the central axis C1 of the cylindrical roller 1. A point on the cross-sectional contour line between two points of exists a curve having a predetermined curvature. The second crowning portion 12 has a circular shape in an arbitrary plane perpendicular to the central axis C1 of the cylindrical roller 1.
In the cross section including the central axis C1 of the cylindrical roller 1, the angle formed by the tangent at any position of the first crowning part 10 and the central axis C1 of the cylindrical roller 1 is equal to any angle of the second crowning part 12 excluding the boundary circle K2. It is larger than the angle between the tangent at the position and the central axis C1 of the cylindrical roller 1.
　図２Ｂは、図２Ａの要部をさらに拡大した図である。
　上述のように、円筒ころ１の中心軸Ｃ１を含む断面において、第１クラウニング部１０の任意の位置での接線と円筒ころ１の中心軸Ｃ１と成す角度は、境界円Ｋ２を除く第２クラウニング部１２の任意の位置での接線と円筒ころ１の中心軸Ｃ１と成す角度よりも大きい。よって、第１クラウニング部１０は、第２クラウニング部１２から第１面取り部２へ向かうに従って、第１ころ延長円すい面Ｅ１に対して漸次離れるように傾斜する。
　第１ころ延長円すい面Ｅ１は、円筒ころ１の中心軸Ｃ１を含む断面において第１クラウニング部１０と第２クラウニング部１２との境界円Ｋ２における第２クラウニング部１２の接線を母線とする仮想円すい面である。つまり、第１ころ延長円すい面Ｅ１は、第２クラウニング部１２の仮想延長面である。 FIG. 2B is a further enlarged view of the main part of FIG. 2A.
As described above, in the cross section including the central axis C1 of the cylindrical roller 1, the angle between the tangent at any position of the first crowning portion 10 and the central axis C1 of the cylindrical roller 1 is the same as that of the second crowning excluding the boundary circle K2. It is larger than the angle between the tangent at any position of the portion 12 and the central axis C1 of the cylindrical roller 1. Therefore, the first crowning part 10 is inclined so as to gradually move away from the first roller extended conical surface E1 as it goes from the second crowning part 12 to the first chamfered part 2.
The first roller extended conical surface E1 is a virtual cone whose generating line is the tangent to the second crowning part 12 in the boundary circle K2 between the first crowning part 10 and the second crowning part 12 in a cross section including the central axis C1 of the cylindrical roller 1. It is a surface. In other words, the first roller extension conical surface E1 is a virtual extension surface of the second crowning portion 12.
　交差円Ｐ１は、第１ころ延長円すい面Ｅ１と、第１境界面Ｌ１とが交差する円である。第１境界面Ｌ１は、境界円Ｋ１を含む仮想平面である。
　交差円Ｐ１は、第１面取り部２と第２クラウニング部１２とを、第１クラウニング部１０を設けることなく繋げたと仮定した場合における、第１面取り部２と第２クラウニング部１２との仮想境界円である。 The intersecting circle P1 is a circle where the first roller extension conical surface E1 and the first boundary surface L1 intersect. The first boundary surface L1 is a virtual plane including the boundary circle K1.
The intersection circle P1 is a virtual boundary between the first chamfered part 2 and the second crowned part 12 when it is assumed that the first chamfered part 2 and the second crowned part 12 are connected without providing the first crowned part 10. It is a yen.
　ここで、境界円Ｋ１の半径と、交差円Ｐ１の半径との差Ｄ１が、３μｍ以上、２０μｍ以下とされる。
　これにより、研磨による突起が境界円Ｋ１近傍に生じたとしても、この突起は第２クラウニング部１２の第１ころ延長円すい面Ｅ１よりも径方向内方側に収められる。これにより、円筒ころ１は、突起が内外輪に接触して軸受の寿命を低下させるのを抑制することができる。 Here, the difference D1 between the radius of the boundary circle K1 and the radius of the intersecting circle P1 is set to be 3 μm or more and 20 μm or less.
As a result, even if a protrusion due to polishing occurs near the boundary circle K1, this protrusion is accommodated inward in the radial direction than the first roller extended conical surface E1 of the second crowning portion 12. Thereby, the cylindrical roller 1 can suppress the protrusions from coming into contact with the inner and outer rings and reducing the life of the bearing.
　第３クラウニング部１６及び第４クラウニング部１８は、第１クラウニング部１０及び第２クラウニング部１２を軸方向の中心を基準に１８０°反転させた構成と同様の構成である。 The third crowning part 16 and the fourth crowning part 18 have the same configuration as the first crowning part 10 and the second crowning part 12 which are reversed by 180 degrees with respect to the center in the axial direction.
〔研磨工程について〕
　図３は、円筒ころ１の製造方法を示す図である。
　図３は、粗形品２０から円筒ころ１を得る研磨工程を示している。
　図３中、粗形品２０は、円筒ころ１の素材である。粗形品２０は、各クラウニング部１０，１２，１６，１８及び円筒部１４を設けることで円筒ころ１となる。
　粗形品２０は、外周面２０ａと、粗形品の軸方向の第１側である第１粗形品端面２０ｂと、粗形品の軸方向の第２側である第２粗形品端面２０ｃと、を有する。
　粗形品２０の外周面２０ａは、第１粗形品面取り部２２と、被研磨面２４と、第２粗形品面取り部２６とを有する。第１粗形品面取り部２２及び第２粗形品面取り部２６は、研磨工程後に、第１面取り部２及び第２面取り部６として残される。
　外周面２０ａにおいて、第１粗形品面取り部２２、被研磨面２４、及び、第２粗形品面取り部２６は、粗形品２０の第１粗形品端面２０ｂ（第１側）から第２粗形品端面２０ｃ（第２側）へ向かって軸方向に沿って順番に並んでいる。 [About the polishing process]
FIG. 3 is a diagram showing a method of manufacturing the cylindrical roller 1.
FIG. 3 shows a polishing process for obtaining the cylindrical roller 1 from the rough-shaped product 20.
In FIG. 3, the rough-shaped product 20 is the material of the cylindrical roller 1. The rough-shaped product 20 becomes the cylindrical roller 1 by providing the crowning parts 10, 12, 16, 18 and the cylindrical part 14.
The rough-shaped product 20 has an outer peripheral surface 20a, a first rough-shaped product end face 20b that is the first side of the coarse-shaped product in the axial direction, and a second rough-shaped product end face that is the second side of the coarse-shaped product in the axial direction. 20c.
The outer peripheral surface 20a of the rough-shaped product 20 has a first rough-shaped product chamfered portion 22, a surface to be polished 24, and a second rough-shaped product chamfered portion 26. The first chamfered part 22 and the second chamfered part 26 remain as the first chamfered part 2 and the second chamfered part 6 after the polishing process.
On the outer circumferential surface 20a, the first rough-shaped product chamfer 22, the surface to be polished 24, and the second rough-shaped product chamfer 26 extend from the first rough-shaped product end surface 20b (first side) of the rough-shaped product 20. 2 are lined up in order along the axial direction toward the end surface 20c (second side) of the rough-shaped product.
　研磨工程において、砥石３０は、被研磨面２４に接触させられる。これにより、各クラウニング部１０，１２，１６，１８及び円筒部１４は、被研磨面２４に設けられる。
　砥石３０は、例えば、アルミナを主成分とした砥粒を用いた砥石である。
　砥石３０は、ほぼ円筒状に形成されている。砥石３０は、回転装置（図示省略）によって砥石３０の中心軸Ｃ２回りに回転可能である。 In the polishing process, the grindstone 30 is brought into contact with the surface to be polished 24 . Thereby, each crowning part 10, 12, 16, 18 and the cylindrical part 14 are provided on the surface to be polished 24.
The whetstone 30 is, for example, a whetstone using abrasive grains containing alumina as a main component.
The grindstone 30 is formed into a substantially cylindrical shape. The grindstone 30 is rotatable around the central axis C2 of the grindstone 30 by a rotating device (not shown).
　砥石３０は、外周面３２と、砥石３０の軸方向の第１側である第１砥石端面３０ａと、砥石３０の軸方向の第２側である第２砥石端面３０ｂと、を有する。
　砥石３０の外周面３２は、第１非接触面３２ａと、接触面３２ｂと、第２非接触面３２ｃと、を有している。両非接触面３２ａ、３２ｃは粗形品２０に接触しない。接触面３２ｂは粗形品２０に接触する。
　第１非接触面３２ａと、接触面３２ｂと、第２非接触面３２ｃと、は、第１砥石端面３０ａから第２砥石端面３０ｂへ向かって軸方向に沿って順番に並んでいる。 The grindstone 30 has an outer peripheral surface 32, a first grindstone end surface 30a that is a first side of the grindstone 30 in the axial direction, and a second grindstone end surface 30b that is a second side of the grindstone 30 in the axial direction.
The outer peripheral surface 32 of the grindstone 30 has a first non-contact surface 32a, a contact surface 32b, and a second non-contact surface 32c. Both non-contact surfaces 32a, 32c do not contact the rough-shaped product 20. The contact surface 32b contacts the rough-shaped product 20.
The first non-contact surface 32a, the contact surface 32b, and the second non-contact surface 32c are arranged in order along the axial direction from the first grindstone end surface 30a toward the second grindstone end surface 30b.
　研磨工程において、砥石３０と粗形品２０とは円筒ころ１の中心軸Ｃ１と砥石３０の中心軸Ｃ２とが平行になるよう配置される。次いで、砥石３０及び粗形品２０は回転させられる。その後、図３中の下段に示すように、粗形品２０の被研磨面２４は砥石３０の外周面（接触面３２ｂ）に接触させられる。 In the polishing process, the grindstone 30 and the rough-shaped product 20 are arranged so that the center axis C1 of the cylindrical roller 1 and the center axis C2 of the grindstone 30 are parallel to each other. Then, the grindstone 30 and the rough shape 20 are rotated. Thereafter, as shown in the lower part of FIG. 3, the polished surface 24 of the rough-shaped product 20 is brought into contact with the outer peripheral surface (contact surface 32b) of the grindstone 30.
　接触面３２ｂは、各クラウニング部１０，１２，１６，１８及び円筒部１４を形成するための複数の面を有している。
　被研磨面２４は、接触面３２ｂによって研磨される。これにより、接触面３２ｂの形状が被研磨面２４に転写される。これにより、各クラウニング部１０，１２，１６，１８及び円筒部１４が、被研磨面２４に形成される。粗形品２０は、各クラウニング部１０，１２，１６，１８及び円筒部１４が、被研磨面２４に形成されて、円筒ころ１になる。 The contact surface 32b has a plurality of surfaces for forming each crowning portion 10, 12, 16, 18 and the cylindrical portion 14.
The surface to be polished 24 is polished by the contact surface 32b. As a result, the shape of the contact surface 32b is transferred to the surface to be polished 24. Thereby, each crowning part 10, 12, 16, 18 and the cylindrical part 14 are formed on the surface to be polished 24. The rough-shaped product 20 becomes the cylindrical roller 1 by forming the crowning parts 10, 12, 16, 18 and the cylindrical part 14 on the surface to be polished 24.
　図４は、砥石３０の断面を示す図である。なお、図４は、断面を示しているが、以下の説明では、主として、断面に現れる外形の各部分について説明する。
　上述のように、接触面３２ｂは、第１傾斜面４０と、第２傾斜面４２と、円筒面（平坦面）４４とを有する。
　接触面３２ｂにおいて、第１傾斜面４０、第２傾斜面４２、及び、円筒面４４は、砥石３０の第１砥石端面３０ａ（第１側）から第２砥石端面３０ｂ（第２側）（図３）へ向かって軸方向に沿って順番に並んでいる。 FIG. 4 is a diagram showing a cross section of the grindstone 30. Note that although FIG. 4 shows a cross section, the following description will mainly describe each part of the external shape that appears in the cross section.
As described above, the contact surface 32b has a first inclined surface 40, a second inclined surface 42, and a cylindrical surface (flat surface) 44.
In the contact surface 32b, the first inclined surface 40, the second inclined surface 42, and the cylindrical surface 44 extend from the first grinding wheel end surface 30a (first side) of the grinding wheel 30 to the second grinding wheel end surface 30b (second side) (Fig. 3) are lined up in order along the axial direction.
　円筒面４４は、円筒部１４を形成するための面である。円筒面４４は、接触面３２ｂの軸方向中央に設けられている。
　第１傾斜面４０及び第２傾斜面４２は、第１非接触面３２ａと円筒面４４との間に設けられている。
　第１傾斜面４０は、第１非接触面３２ａに繋がっている。第１傾斜面４０は、第１クラウニング部１０を形成するための面である。
　第１傾斜面４０は曲面を有する。第１傾斜面４０は、砥石３０の中心軸Ｃ２を含む断面において、第１傾斜面４０の断面輪郭線の任意の２点を結ぶ仮想直線より砥石３０の中心軸Ｃ２側に任意の２点の間の断面輪郭線上の点が存在する所定の曲率を有する曲線（後述する第１傾斜線部ＰＬ１）を有する。第１傾斜面４０は、砥石３０の中心軸Ｃ２に垂直な任意の断面において円形を有する。 The cylindrical surface 44 is a surface for forming the cylindrical portion 14. The cylindrical surface 44 is provided at the axial center of the contact surface 32b.
The first inclined surface 40 and the second inclined surface 42 are provided between the first non-contact surface 32a and the cylindrical surface 44.
The first inclined surface 40 is connected to the first non-contact surface 32a. The first inclined surface 40 is a surface for forming the first crowning part 10.
The first inclined surface 40 has a curved surface. The first inclined surface 40 has two arbitrary points on the central axis C2 side of the grinding wheel 30 from a virtual straight line connecting arbitrary two points on the cross-sectional contour line of the first inclined surface 40 in a cross section including the central axis C2 of the grinding wheel 30. It has a curved line (a first inclined line portion PL1 to be described later) having a predetermined curvature in which a point on the cross-sectional contour exists between. The first inclined surface 40 has a circular shape in any cross section perpendicular to the central axis C2 of the grindstone 30.
　第２傾斜面４２は、第１傾斜面４０と円筒面４４との間に設けられている。第２傾斜面４２は、第２クラウニング部１２を形成するための面である。
　第２傾斜面４２は曲面を有する。第２傾斜面４２は、砥石３０の中心軸Ｃ２を含む断面において、第２傾斜面４２の断面輪郭線の任意の２点を結ぶ仮想直線より砥石３０の中心軸Ｃ２側に任意の２点の間の断面輪郭線上の点が存在する所定の曲率を有する曲線（後述する第２傾斜線部ＰＬ２）を有する。第２傾斜面４２は、砥石３０の中心軸Ｃ２に垂直な任意の断面において円形を有する。
　接触面３２ｂに含まれる各面は、滑らかに繋がっている。 The second inclined surface 42 is provided between the first inclined surface 40 and the cylindrical surface 44. The second inclined surface 42 is a surface for forming the second crowning part 12.
The second inclined surface 42 has a curved surface. The second inclined surface 42 has two arbitrary points on the central axis C2 side of the grinding wheel 30 from a virtual straight line connecting arbitrary two points on the cross-sectional contour of the second inclined surface 42 in a cross section including the central axis C2 of the grinding wheel 30. It has a curved line (second inclined line portion PL2 to be described later) having a predetermined curvature in which a point on the cross-sectional contour exists between. The second inclined surface 42 has a circular shape in any cross section perpendicular to the central axis C2 of the grindstone 30.
Each surface included in the contact surface 32b is smoothly connected.
　接触面３２ｂの中心軸Ｃ２を含む軸方向断面における輪郭線ＰＬは、第１傾斜線部ＰＬ１と、第２傾斜線部ＰＬ２と、直線部ＰＬ５とを有する。
　第１傾斜線部ＰＬ１は、第１傾斜面４０に対応する輪郭線である。よって、第１傾斜線部ＰＬ１は、第１クラウニング部１０の中心軸Ｃ１を含む断面における曲線の曲率と同じ曲率の曲線である。
　第２傾斜線部ＰＬ２は、第２傾斜面４２に対応する輪郭線である。よって、第２傾斜線部ＰＬ２は、第２クラウニング部１２の中心軸Ｃ１を含む断面における曲線の曲率と同じ曲率の曲線である。
　直線部ＰＬ５は、円筒面４４に対応する輪郭線である。直線部ＰＬ５は、中心軸Ｃ２に平行な直線である。 The contour line PL in the axial cross section including the central axis C2 of the contact surface 32b has a first inclined line part PL1, a second inclined line part PL2, and a straight line part PL5.
The first inclined line portion PL1 is a contour line corresponding to the first inclined surface 40. Therefore, the first inclined line portion PL1 is a curved line having the same curvature as the curvature of the curved line in the cross section including the central axis C1 of the first crowning portion 10.
The second inclined line portion PL2 is a contour line corresponding to the second inclined surface 42. Therefore, the second inclined line portion PL2 is a curved line having the same curvature as the curvature of the curved line in the cross section including the central axis C1 of the second crowning portion 12.
The straight line portion PL5 is a contour line corresponding to the cylindrical surface 44. The straight line portion PL5 is a straight line parallel to the central axis C2.
　図４中、第１境界円Ｂ１は、第１非接触面３２ａと第１傾斜面４０との境界である。第１境界円Ｂ１は、第１面取り部２と第１クラウニング部１０との境界円Ｋ１に接する。
　第２境界円Ｂ２は、第１傾斜面４０と第２傾斜面４２との境界である。第２境界円Ｂ２は、第１クラウニング部１０と第２クラウニング部１２との境界円Ｋ２に接する。 In FIG. 4, the first boundary circle B1 is the boundary between the first non-contact surface 32a and the first inclined surface 40. The first boundary circle B1 is in contact with the boundary circle K1 between the first chamfered part 2 and the first crowning part 10.
The second boundary circle B2 is the boundary between the first inclined surface 40 and the second inclined surface 42. The second boundary circle B2 touches the boundary circle K2 between the first crowning part 10 and the second crowning part 12.
　また、第１円すい面Ｅ１０は、第２傾斜面４２を第２境界円Ｂ２よりも軸方向の第１側へ延長した仮想円すい面である。第１円すい面Ｅ１０の母線は、第１接線Ｅ１１０に沿っている。第１接線Ｅ１１０は、中心軸Ｃ２を含む断面において、第２境界円Ｂ２上の第２傾斜面４２に対する接線である。
　つまり、第１円すい面Ｅ１０は、第２境界円Ｂ２において砥石３０の中心軸Ｃ２を含む断面における第２傾斜線部ＰＬ２の接線を、軸方向の第１側へ向けて延長し、砥石３０の中心軸Ｃ２の周方向に積分した円すい面である。 Further, the first conical surface E10 is a virtual conical surface that extends the second inclined surface 42 toward the first side in the axial direction from the second boundary circle B2. The generatrix of the first conical surface E10 is along the first tangent E110. The first tangent E110 is a tangent to the second inclined surface 42 on the second boundary circle B2 in the cross section including the central axis C2.
That is, the first conical surface E10 extends the tangent of the second inclined line portion PL2 in the cross section including the central axis C2 of the grinding wheel 30 in the second boundary circle B2 toward the first side in the axial direction, and It is a conical surface integrated in the circumferential direction of the central axis C2.
　また、第１境界面Ｌ１は、上述したように、第１境界円Ｂ１（境界円Ｋ１）を含む仮想平面である。
　よって、研磨工程終了時に境界円Ｋ１と第１境界円Ｂ１とが一致している時、第１ころ延長円すい面Ｅ１と第１円すい面Ｅ１０とは重なる。
　また、第１交差円Ｐ１０は、第１境界面Ｌ１と第１円すい面Ｅ１０とが交差する円である。
　ここで、本実施形態では、第１交差円Ｐ１０の半径と、第１境界円Ｂ１の半径との差Ｄ１０が、３μｍ以上、２０μｍ以下とされる。 Further, as described above, the first boundary surface L1 is a virtual plane including the first boundary circle B1 (boundary circle K1).
Therefore, when the boundary circle K1 and the first boundary circle B1 coincide at the end of the polishing process, the first roller extension conical surface E1 and the first conical surface E10 overlap.
Moreover, the first intersecting circle P10 is a circle where the first boundary surface L1 and the first conical surface E10 intersect.
Here, in this embodiment, the difference D10 between the radius of the first intersecting circle P10 and the radius of the first boundary circle B1 is 3 μm or more and 20 μm or less.
　上記構成によって得られる円筒ころ１の境界円Ｋ１の径方向位置は、円筒ころ１の外周面１ａに第２クラウニング部１２のみを設けた場合における第１面取り部２と第２クラウニング部１２との境界（交差円Ｐ１）の径方向位置よりも円筒ころ１の中心軸Ｃ１寄りになる。これにより、上記実施形態によって得られた軸受用ころは、第１面取り部２と第１クラウニング部１０との境界円Ｋ１近傍に突起が生じたとしても、この突起を第２クラウニング部１２の第１ころ延長円すい面Ｅ１（図２Ｂ）よりも径方向内方側に収めることができ、突起が内外輪に接触して軸受の寿命を低下させるのを抑制することができる。
　上記差Ｄ１０が３μｍより小さい場合、突起は第２クラウニング部１２の第１ころ延長円すい面Ｅ１よりも径方向外方へ突出して形成されるおそれがある。また、差Ｄ１０が２０μｍよりも大きい場合、被研磨面２４の研磨量は必要以上に大きくなる。研磨量の増大は、コスト増加に繋がるおそれがある。
　上記製造方法は、差Ｄ１０を３μｍ以上、２０μｍ以下とすることで、軸受寿命低下の抑制が可能な円筒ころ１を得ることができる。 The radial position of the boundary circle K1 of the cylindrical roller 1 obtained by the above configuration is the difference between the first chamfered part 2 and the second crowned part 12 when only the second crowned part 12 is provided on the outer peripheral surface 1a of the cylindrical roller 1. It is closer to the center axis C1 of the cylindrical roller 1 than the radial position of the boundary (crossing circle P1). As a result, in the bearing roller obtained according to the above embodiment, even if a protrusion is generated in the vicinity of the boundary circle K1 between the first chamfered part 2 and the first crowning part 10, this protrusion is removed from the second crowning part 12. The first roller can be placed radially inward from the extended conical surface E1 (FIG. 2B), and it is possible to prevent the protrusion from contacting the inner and outer rings and reducing the life of the bearing.
If the difference D10 is smaller than 3 μm, the protrusion may be formed to protrude radially outward from the first roller extended conical surface E1 of the second crowning portion 12. Moreover, when the difference D10 is larger than 20 μm, the amount of polishing of the surface to be polished 24 becomes larger than necessary. An increase in the amount of polishing may lead to an increase in cost.
In the above manufacturing method, by setting the difference D10 to 3 μm or more and 20 μm or less, it is possible to obtain a cylindrical roller 1 that can suppress a decrease in bearing life.
　なお、差Ｄ１０の下限値は、好ましくは５μｍ以上である。下限値を５μｍ以上とすることで、上記製造方法は、より確実に、境界円Ｋ１近傍に生じる突起を、第１ころ延長円すい面Ｅ１よりも径方向内方側に収めることができる。
　また、差Ｄ１０の上限値は、好ましくは１０μｍ以下である。上限値を１０μｍ以下とすることで、上記製造方法は、確実にコスト増加を抑制できる。 Note that the lower limit of the difference D10 is preferably 5 μm or more. By setting the lower limit to 5 μm or more, the manufacturing method described above can more reliably accommodate the protrusion that occurs near the boundary circle K1 on the radially inward side of the first roller extension conical surface E1.
Further, the upper limit of the difference D10 is preferably 10 μm or less. By setting the upper limit to 10 μm or less, the above manufacturing method can reliably suppress an increase in cost.
　図４に示すように、本実施形態において、第２境界円Ｂ２と第１境界円Ｂ１との間の軸方向の距離を第１間隔Ｗ１、境界円Ｂ１０と、第１境界円Ｂ１との間の軸方向の距離を第２間隔Ｗ２とするとき、第２間隔Ｗ２に対する第１間隔Ｗ１の割合は、１／２０以上、１／２以下であることが好ましい。なお、境界円Ｂ１０（第５境界円）は、第２傾斜面４２と、円筒面４４との境界である。 As shown in FIG. 4, in this embodiment, the distance in the axial direction between the second boundary circle B2 and the first boundary circle B1 is the first interval W1, and the distance between the boundary circle B10 and the first boundary circle B1 is When the distance in the axial direction is defined as the second interval W2, the ratio of the first interval W1 to the second interval W2 is preferably 1/20 or more and 1/2 or less. Note that the boundary circle B10 (fifth boundary circle) is the boundary between the second inclined surface 42 and the cylindrical surface 44.
　第２間隔Ｗ２に対する第１間隔Ｗ１の割合を１／２０よりも小さくすると、円筒ころ１の径寸法によっては、第１傾斜面４０によって形成される第１クラウニング部１０は、軸方向の範囲が小さくなり、第１クラウニング部１０として必要な範囲を確保できないおそれがある。第２間隔に対する第１間隔の割合を１／２よりも大きくすると、第１傾斜面４０によって形成される第１クラウニング部１０は、軸方向の範囲が必要以上に大きくなり、研磨量が大きくなることでコスト増加に繋がるおそれがある。
　第２間隔Ｗ２に対する第１間隔Ｗ１の割合を１／２０以上、１／２以下とすることで、上記製造方法は、好適な軸方向の範囲で第１クラウニング部１０を設けることができる。 If the ratio of the first interval W1 to the second interval W2 is smaller than 1/20, depending on the diameter of the cylindrical roller 1, the first crowning part 10 formed by the first inclined surface 40 may have a narrower axial range. If the first crowning part 10 becomes smaller, there is a possibility that the necessary range for the first crowning part 10 cannot be secured. If the ratio of the first interval to the second interval is larger than 1/2, the first crowning portion 10 formed by the first inclined surface 40 will have a larger axial range than necessary, and the amount of polishing will increase. This may lead to an increase in costs.
By setting the ratio of the first interval W1 to the second interval W2 to be 1/20 or more and 1/2 or less, the above manufacturing method can provide the first crowning portion 10 in a suitable axial range.
　なお、第２間隔Ｗ２に対する第１間隔Ｗ１の割合の下限値は、好ましくは、１／７以上である。前記下限値を１／７以上とすることで、上記製造方法は、より確実に、好適な軸方向の範囲で第１クラウニング部１０を設けることができる。 Note that the lower limit of the ratio of the first interval W1 to the second interval W2 is preferably 1/7 or more. By setting the lower limit to 1/7 or more, the manufacturing method described above can more reliably provide the first crowning portion 10 in a suitable axial range.
　図２Ａに示すように、上記砥石３０で形成された円筒ころ１の第１クラウニング部１０の軸方向幅を第１クラウニング幅ＣＷ１、第１クラウニング部１０及び第２クラウニング部１２を含むクラウニング部全体の軸方向幅を全体クラウニング幅ＣＷとしたとき、全体クラウニング幅ＣＷに対する第１クラウニング幅ＣＷ１は、以下のように設定することができる。
　すなわち、全体クラウニング幅ＣＷが１．５ｍｍ以上、３ｍｍ未満である場合、第１クラウニング幅ＣＷ１は０．５ｍｍとすることが好ましい。
　また、全体クラウニング幅ＣＷが３ｍｍ以上、６ｍｍ未満である場合、第１クラウニング幅ＣＷ１は１．０ｍｍとすることが好ましい。
　また、全体クラウニング幅ＣＷが６ｍｍ以上である場合、第１クラウニング幅ＣＷ１は２ｍｍとすることが好ましい。 As shown in FIG. 2A, the axial width of the first crowning part 10 of the cylindrical roller 1 formed by the grindstone 30 is the first crowning width CW1, and the entire crowning part including the first crowning part 10 and the second crowning part 12 When the axial width of is set as the overall crowning width CW, the first crowning width CW1 relative to the overall crowning width CW can be set as follows.
That is, when the overall crowning width CW is 1.5 mm or more and less than 3 mm, it is preferable that the first crowning width CW1 is 0.5 mm.
Further, when the overall crowning width CW is 3 mm or more and less than 6 mm, it is preferable that the first crowning width CW1 is 1.0 mm.
Further, when the overall crowning width CW is 6 mm or more, it is preferable that the first crowning width CW1 is 2 mm.
　図５は、砥石３０の断面を示す図である。図５は、砥石３０の第２砥石端面３０ｂを含む断面を示している。なお、図５は、断面を示しているが、以下の説明では、主として、断面に現れる外形の各部分について説明する。
　上述したように、円筒ころ１の外周面１ａは、第２面取り部６、第３クラウニング部１６、及び第４クラウニング部１８を有する。
　第２面取り部６、第３クラウニング部１６、及び第４クラウニング部１８は、円筒ころ１の第２ころ端面１ｃ（第２側）から第１ころ端面１ｂ（第１側）へ向かって軸方向に沿って順番に並んでいる。 FIG. 5 is a diagram showing a cross section of the grindstone 30. FIG. 5 shows a cross section of the grindstone 30 including the second grindstone end surface 30b. Note that although FIG. 5 shows a cross section, the following description will mainly describe each part of the external shape that appears in the cross section.
As described above, the outer circumferential surface 1a of the cylindrical roller 1 has the second chamfered portion 6, the third crowned portion 16, and the fourth crowned portion 18.
The second chamfered portion 6, the third crowned portion 16, and the fourth crowned portion 18 extend in the axial direction from the second roller end surface 1c (second side) of the cylindrical roller 1 toward the first roller end surface 1b (first side). are lined up in order along.
　第３クラウニング部１６は、第２面取り部６に繋がっている。第４クラウニング部１８は、第３クラウニング部１６と円筒部１４との間に設けられている。
　第３クラウニング部１６は、第１クラウニング部１０と同様の形状を有する。第４クラウニング部１８は、第２クラウニング部１２と同様の形状を有する。
　よって、第３クラウニング部１６及び第４クラウニング部１８についての説明は省略する。 The third crowning portion 16 is connected to the second chamfered portion 6. The fourth crowning part 18 is provided between the third crowning part 16 and the cylindrical part 14.
The third crowning part 16 has a similar shape to the first crowning part 10. The fourth crowning part 18 has a similar shape to the second crowning part 12.
Therefore, description of the third crowning part 16 and the fourth crowning part 18 will be omitted.
　接触面３２ｂは、第３傾斜面５０と、第４傾斜面５２とをさらに有する。
　接触面３２ｂにおいて、第３傾斜面５０、第４傾斜面５２、及び、円筒面４４は、砥石３０の第２砥石端面３０ｂ（第２側）から第１砥石端面３０ａ（第１側）（図３）へ向かって軸方向に沿って順番に並んでいる。
　第３傾斜面５０及び第４傾斜面５２は、第２非接触面３２ｃと円筒面４４との間に設けられている。
　第３傾斜面５０は、第２非接触面３２ｃに繋がっている。第３傾斜面５０は、第３クラウニング部１６を形成するための面である。
　第３傾斜面５０は曲面を有する。第３傾斜面５０は、砥石３０の中心軸Ｃ２を含む断面において、第３傾斜面５０の断面輪郭線の任意の２点を結ぶ仮想直線より砥石３０の中心軸Ｃ２側に任意の２点の間の断面輪郭線上の点が存在する所定の曲率を有する曲線（後述する第３傾斜線部ＰＬ３）を有する。第３傾斜面５０は、砥石３０の中心軸Ｃ２に垂直な任意の断面において円形を有する。 The contact surface 32b further includes a third inclined surface 50 and a fourth inclined surface 52.
In the contact surface 32b, the third inclined surface 50, the fourth inclined surface 52, and the cylindrical surface 44 are connected from the second grinding wheel end surface 30b (second side) of the grinding wheel 30 to the first grinding wheel end surface 30a (first side) (Fig. 3) are lined up in order along the axial direction.
The third inclined surface 50 and the fourth inclined surface 52 are provided between the second non-contact surface 32c and the cylindrical surface 44.
The third inclined surface 50 is connected to the second non-contact surface 32c. The third inclined surface 50 is a surface for forming the third crowning portion 16.
The third inclined surface 50 has a curved surface. The third inclined surface 50 has two arbitrary points on the central axis C2 side of the grinding wheel 30 from a virtual straight line connecting arbitrary two points on the cross-sectional contour line of the third inclined surface 50 in a cross section including the central axis C2 of the grinding wheel 30. A curve having a predetermined curvature (a third inclined line portion PL3 to be described later) exists where a point on the cross-sectional contour exists. The third inclined surface 50 has a circular shape in any cross section perpendicular to the central axis C2 of the grindstone 30.
　第４傾斜面５２は、第３傾斜面５０と円筒面４４との間に設けられている。第４傾斜面５２は、第４クラウニング部１８を形成するための面である。
　第４傾斜面５２は曲面を有する。第４傾斜面５２は、砥石３０の中心軸Ｃ２を含む断面において、第４傾斜面５２の断面輪郭線の任意の２点を結ぶ仮想直線より砥石３０の中心軸Ｃ２側に任意の２点の間の断面輪郭線上の点が存在する所定の曲率を有する曲線（後述する第４傾斜線部ＰＬ４）を有する。第４傾斜面５２は、砥石３０の中心軸Ｃ２に垂直な任意の断面において円形を有する。 The fourth inclined surface 52 is provided between the third inclined surface 50 and the cylindrical surface 44. The fourth inclined surface 52 is a surface for forming the fourth crowning portion 18.
The fourth inclined surface 52 has a curved surface. The fourth inclined surface 52 has two arbitrary points on the central axis C2 side of the grinding wheel 30 from a virtual straight line connecting arbitrary two points on the cross-sectional contour of the fourth inclined surface 52 in a cross section including the central axis C2 of the grinding wheel 30. A curve having a predetermined curvature (a fourth inclined line portion PL4 to be described later) exists where a point on the cross-sectional contour exists. The fourth inclined surface 52 has a circular shape in any cross section perpendicular to the central axis C2 of the grindstone 30.
　輪郭線ＰＬは、第３傾斜線部ＰＬ３と、第４傾斜線部ＰＬ４とをさらに有する。
　第３傾斜線部ＰＬ３は、第３傾斜面５０に対応する輪郭線である。よって、第３傾斜線部ＰＬ３は、第３クラウニング部１６の中心軸Ｃ１を含む断面における曲線の曲率と同じ曲率の曲線である。
　第４傾斜線部ＰＬ４は、第４傾斜面５２に対応する輪郭線である。よって、第４傾斜線部ＰＬ４は、第４クラウニング部１８の中心軸Ｃ１を含む断面における曲線の曲率と同じ曲率の曲線である。 The contour line PL further includes a third slope line part PL3 and a fourth slope line part PL4.
The third inclined line portion PL3 is a contour line corresponding to the third inclined surface 50. Therefore, the third inclined line portion PL3 is a curved line having the same curvature as the curvature of the curved line in the cross section including the central axis C1 of the third crowning portion 16.
The fourth inclined line portion PL4 is a contour line corresponding to the fourth inclined surface 52. Therefore, the fourth inclined line portion PL4 is a curved line having the same curvature as the curvature of the curved line in the cross section including the central axis C1 of the fourth crowning portion 18.
　図５中、第３境界円Ｂ３は、第２非接触面３２ｃと第３傾斜面５０との境界である。第３境界円Ｂ３は、第２面取り部６と第３クラウニング部１６との境界円Ｋ４に接する。
　第４境界円Ｂ４は、第３傾斜面５０と第４傾斜面５２との境界である。第４境界円Ｂ４は、第３クラウニング部１６と第４クラウニング部１８との境界円Ｋ５に接する。 In FIG. 5, the third boundary circle B3 is the boundary between the second non-contact surface 32c and the third inclined surface 50. The third boundary circle B3 touches the boundary circle K4 between the second chamfered portion 6 and the third crowning portion 16.
The fourth boundary circle B4 is the boundary between the third inclined surface 50 and the fourth inclined surface 52. The fourth boundary circle B4 touches the boundary circle K5 between the third crowning part 16 and the fourth crowning part 18.
　また、第２円すい面Ｅ１２は、第４傾斜面５２を第４境界円Ｂ４よりも軸方向の第２側へ延長した仮想円すい面である。第２円すい面Ｅ１２の母線は、第２接線Ｅ１１２に沿っている。第２接線Ｅ１１２は、中心軸Ｃ２を含む断面において、第４境界円Ｂ４上の第４傾斜面５２に対する接線である。
　つまり、第２円すい面Ｅ１２は、第４境界円Ｂ４において砥石３０の中心軸Ｃ２を含む断面における第２傾斜線部ＰＬ４の接線を、軸方向の第２側へ向けて延長し、砥石３０の中心軸Ｃ１の周方向に積分した円すい面である。 Further, the second conical surface E12 is a virtual conical surface obtained by extending the fourth inclined surface 52 toward the second side in the axial direction from the fourth boundary circle B4. The generatrix of the second conical surface E12 is along the second tangent line E112. The second tangent E112 is a tangent to the fourth inclined surface 52 on the fourth boundary circle B4 in the cross section including the central axis C2.
That is, the second conical surface E12 extends the tangent of the second inclined line portion PL4 in the cross section including the central axis C2 of the grinding wheel 30 in the fourth boundary circle B4 toward the second side in the axial direction, and It is a conical surface integrated in the circumferential direction of the central axis C1.
　また、第２境界面Ｌ２は、第３境界円Ｂ３（境界円Ｋ４）を含む仮想平面である。
　よって、研磨工程終了時に境界円Ｋ４と第３境界円Ｂ３とが一致している時、第２ころ延長円すい面Ｅ２と第２仮想延長円すい面Ｅ１２とは重なる。
　第２ころ延長円すい面Ｅ２は、円筒ころ１の中心軸Ｃ１を含む断面において、境界円Ｋ５における第４クラウニング部１８の接線を母線とする仮想円すい面である。つまり、第２ころ延長円すい面Ｅ２は、第４クラウニング部１８の仮想延長面である。
　また、第２交差円Ｐ１２は、第２境界面Ｌ２と第２円すい面Ｅ１２とが交差する円である。 Further, the second boundary surface L2 is a virtual plane including the third boundary circle B3 (boundary circle K4).
Therefore, when the boundary circle K4 and the third boundary circle B3 coincide at the end of the polishing process, the second roller extended conical surface E2 and the second virtual extended conical surface E12 overlap.
The second roller extended conical surface E2 is a virtual conical surface whose generatrix is a tangent to the fourth crowning portion 18 in the boundary circle K5 in a cross section including the central axis C1 of the cylindrical roller 1. In other words, the second roller extension conical surface E2 is a virtual extension surface of the fourth crowning portion 18.
Further, the second intersecting circle P12 is a circle where the second boundary surface L2 and the second conical surface E12 intersect.
　ここで、第２交差円Ｐ１２の半径と、第３境界円Ｂ３の半径との差Ｄ１２が、差Ｄ１０と同様、３μｍ以上、２０μｍ以下とされる。
　上記実施形態によって得られた軸受用ころは、この砥石３０によって得られる円筒ころ１の境界円Ｋ４近傍に突起が生じたとしても、この突起を第４クラウニング部１８の第２ころ延長円すい面Ｅ２よりも径方向内方側に収めることができ、突起が内外輪に接触して軸受の寿命を低下させるのを抑制することができる。 Here, the difference D12 between the radius of the second intersecting circle P12 and the radius of the third boundary circle B3 is set to be 3 μm or more and 20 μm or less, similar to the difference D10.
In the bearing roller obtained by the above embodiment, even if a protrusion is generated near the boundary circle K4 of the cylindrical roller 1 obtained by this grindstone 30, the protrusion is transferred to the second roller extension conical surface E2 of the fourth crowning part 18. This can prevent the protrusions from coming into contact with the inner and outer rings and shortening the life of the bearing.
　このように、本実施形態は、砥石の接触面３２ｂにおける第１砥石端面３０ａ及び第２砥石端面３０ｂの両方に上述の条件を満たす各傾斜面４０，４２，５０，５２を設けたので、軸受寿命低下の抑制が可能な円筒ころ１を得ることができる。 In this way, in this embodiment, since the inclined surfaces 40, 42, 50, and 52 that satisfy the above-mentioned conditions are provided on both the first grindstone end face 30a and the second grindstone end face 30b on the contact surface 32b of the grindstone, the bearing It is possible to obtain a cylindrical roller 1 that can suppress a decrease in life.
　図６は、本実施形態の円筒ころ１が用いられる円筒ころ軸受６０の断面図である。
　円筒ころ軸受６０は、複数の円筒ころ１の他、内輪６２と、外輪６４と、保持器６６とを備える。複数の円筒ころ１は、内輪６２の軌道面６２ａと、外輪６４の軌道面６４ａとの間に転動自在に介在する。保持器６６は、複数の円筒ころ１を周方向に一定間隔で保持する。
　本実施形態の円筒ころ１が用いられた円筒ころ１は、上述のように、寿命低下が抑制される。 FIG. 6 is a cross-sectional view of a cylindrical roller bearing 60 in which the cylindrical roller 1 of this embodiment is used.
The cylindrical roller bearing 60 includes, in addition to the plurality of cylindrical rollers 1, an inner ring 62, an outer ring 64, and a retainer 66. The plurality of cylindrical rollers 1 are rotatably interposed between a raceway surface 62a of the inner ring 62 and a raceway surface 64a of the outer ring 64. The cage 66 holds the plurality of cylindrical rollers 1 at regular intervals in the circumferential direction.
As described above, the cylindrical roller 1 using the cylindrical roller 1 of this embodiment has a reduced life span.
〔その他〕
　今回開示した実施形態はすべての点で例示であって制限的なものではない。
　例えば、本実施形態は、第１クラウニング部１０及び第３クラウニング部１６が所定の曲率を有する凸曲面であり、砥石３０の輪郭線ＰＬの第１傾斜線部ＰＬ１及び第３傾斜線部ＰＬ３が、第１クラウニング部１０及び第３クラウニング部１６に対応する曲線である場合であった。一方、本発明は、第１クラウニング部１０及び第３クラウニング部１６が円すい面であり、第１傾斜線部ＰＬ１及び第３傾斜線部ＰＬ３が直線であってもよい。 〔others〕
The embodiments disclosed herein are illustrative in all respects and are not restrictive.
For example, in this embodiment, the first crowning part 10 and the third crowning part 16 are convex curved surfaces having a predetermined curvature, and the first inclined line part PL1 and the third inclined line part PL3 of the contour line PL of the grindstone 30 are , the curves correspond to the first crowning part 10 and the third crowning part 16. On the other hand, in the present invention, the first crowning part 10 and the third crowning part 16 may be conical surfaces, and the first inclined line part PL1 and the third inclined line part PL3 may be straight lines.
　また、本実施形態は、第２クラウニング部１２及び第４クラウニング部１８が所定の曲率を有する凸曲面であり、砥石３０の輪郭線ＰＬの第２傾斜線部ＰＬ２及び第４傾斜線部ＰＬ４が、第２クラウニング部１２及び第４クラウニング部１８に対応する曲線である場合であった。一方、本発明は、第２クラウニング部１２及び第４クラウニング部１８が円すい面であり、第２傾斜線部ＰＬ２及び第４傾斜線部ＰＬ４が直線であってもよい。 Moreover, in this embodiment, the second crowning part 12 and the fourth crowning part 18 are convex curved surfaces having a predetermined curvature, and the second slope line part PL2 and the fourth slope line part PL4 of the contour line PL of the grindstone 30 are , the curves correspond to the second crowning part 12 and the fourth crowning part 18. On the other hand, in the present invention, the second crowning part 12 and the fourth crowning part 18 may be conical surfaces, and the second inclined line part PL2 and the fourth inclined line part PL4 may be straight lines.
　また、本実施形態は、円筒ころ１が円筒部１４を有し、砥石３０が円筒面４４を有している場合であった。一方、本発明は、円筒ころ１は第２クラウニング部１２と第４クラウニング部１８とが繋がっていてもよいし、一体のクラウニング部を構成していてもよい。
　さらに、本発明は、砥石３０は第２傾斜面４２と、第４傾斜面５２とが繋がっていてもよいし、一体の傾斜面を構成していてもよい。 Further, in this embodiment, the cylindrical roller 1 has the cylindrical portion 14 and the grindstone 30 has the cylindrical surface 44. On the other hand, in the present invention, the second crowning part 12 and the fourth crowning part 18 of the cylindrical roller 1 may be connected to each other, or may constitute an integrated crowning part.
Furthermore, in the present invention, the second inclined surface 42 and the fourth inclined surface 52 of the grindstone 30 may be connected to each other, or may constitute an integrated inclined surface.
　また、本実施形態は円筒ころ軸受に用いられる円筒ころについて例示したが、本実施形態にて開示したころの製造方法は、円すいころ、棒状ころ、針状ころ等、円筒ころ以外のころに対しても適用可能である。 Furthermore, although this embodiment has been exemplified with respect to cylindrical rollers used in cylindrical roller bearings, the method for manufacturing rollers disclosed in this embodiment is applicable to rollers other than cylindrical rollers, such as tapered rollers, bar rollers, needle rollers, etc. It is also applicable.
　本発明の権利範囲は、上述の実施形態に限定されるものではなく、請求の範囲に記載された構成と均等の範囲内でのすべての変更が含まれる。 The scope of the present invention is not limited to the above-described embodiments, and includes all modifications within the scope of equivalents to the configurations described in the claims.
１　円筒ころ　　　　　　　１ａ　外周面　　　　　１ｂ　第１ころ端面
１ｃ　第２ころ端面　　　　２　第１面取り部　　　４　外径面
６　第２面取り部　　　　　１０　第１クラウニング部
１２　第２クラウニング部　１４　円筒部
１６　第３クラウニング部　１８　第４クラウニング部
２０　粗形品　　　　　　　２０ａ　外周面
２０ｂ　第１粗形品端面　　２０ｃ　第２粗形品端面
２２　第１粗形品面取り部　２４　被研磨面
２６　第２粗形品面取り部　３０　砥石　　　　　３０ａ　第１砥石端面
３０ｂ　第２砥石端面　　　３２　外周面　　　　３２ａ　第１非接触面
３２ｂ　接触面　　　　　　３２ｃ　第２非接触面
４０　第１傾斜面　　　　　４２　第２傾斜面　　４４　円筒面
５０　第３傾斜面　　　　　５２　第４傾斜面　　６０　軸受
６２　内輪　　　　　　　　６２ａ　軌道面　　　６４　外輪
６４ａ　軌道面　　　　　　６６　保持器　　　　Ｂ１　第１境界円
Ｂ２　第２境界円　　　　　Ｂ３　第３境界円　　Ｂ４　第４境界円
Ｂ１０　境界円（第５境界円）　　　　　　　　　Ｃ１　中心軸
Ｃ２　中心軸　　　　　　　ＣＷ　全体クラウニング幅
ＣＷ１　第１クラウニング幅　　　　　Ｅ１　第１ころ延長円すい面
Ｅ１０　第１円すい面　　　Ｅ１１０　第１接線　Ｅ１１２　第２接線
Ｅ１２　第２円すい面　　　Ｅ２　第２ころ延長円すい面
Ｋ１　境界円　　　　　　　Ｋ２　境界円　　　　Ｋ４　境界円
Ｋ５　境界円　　　　　　　Ｌ１　第１境界面　　Ｌ２　第２境界面
Ｐ１　交差円　　　　　　　Ｐ１０　第１交差円　Ｐ１２　第２交差円
ＰＬ　輪郭線　　　　　　　ＰＬ１　第１傾斜線部
ＰＬ２　第２傾斜線部　　　ＰＬ３　第３傾斜線部
ＰＬ４　第４傾斜線部　　　ＰＬ５　直線部
  1 Cylindrical roller 1a Outer peripheral surface 1b First roller end surface 1c Second roller end surface 2 First chamfered portion 4 Outer diameter surface 6 Second chamfered portion 10 First crowning portion 12 Second crowning portion 14 Cylindrical portion 16 Third crowning portion 18 4 Crowning part 20 Rough-shaped product 20a Outer surface 20b First rough-shaped product end face 20c Second rough-shaped product end face 22 First rough-shaped product chamfered part 24 Polished surface 26 Second rough-shaped product chamfered part 30 Grindstone 30a First grindstone End surface 30b Second grindstone end surface 32 Outer peripheral surface 32a First non-contact surface 32b Contact surface 32c Second non-contact surface 40 First inclined surface 42 Second inclined surface 44 Cylindrical surface 50 Third inclined surface 52 Fourth inclined surface 60 Bearing 62 Inner ring 62a Raceway surface 64 Outer ring 64a Raceway surface 66 Cage B1 First boundary circle B2 Second boundary circle B3 Third boundary circle B4 Fourth boundary circle B10 Boundary circle (fifth boundary circle) C1 Center axis C2 Center axis CW Overall crowning Width CW1 First crowning width E1 First roller extension conical surface E10 First conical surface E110 First tangent E112 Second tangent E12 Second conical surface E2 Second roller extension conical surface K1 Boundary circle K2 Boundary circle K4 Boundary circle K5 Boundary circle L1 First boundary surface L2 Second boundary surface P1 Intersecting circle P10 First intersecting circle P12 Second intersecting circle PL Contour line PL1 First inclined line part PL2 Second inclined line part PL3 Third inclined line part PL4 Fourth inclined line part PL5 Straight section

Claims (3)

  1. 　軸受用ころの製造方法であって、
    　前記軸受用ころの粗形品の外周面は、前記粗形品の軸方向の第１側から第２側へ向かって順番に並ぶ、第１粗形品面取り部と、被研磨面と、を有し、
    　前記軸受用ころの外周面は、前記軸受用ころの軸方向の第１側から第２側へ向かって順番に並ぶ、第１面取り部と、第１クラウニング部と、第２クラウニング部と、を有し、
    　前記被研磨面に対して砥石を接触させ、前記第１粗形品面取り部を前記第１面取り部として残しつつ、前記第１クラウニング部、及び前記第２クラウニング部を前記被研磨面に形成し、前記粗形品から前記軸受用ころを得る研磨工程を含み、
    　前記砥石は、前記粗形品に接触する接触面と、前記粗形品の前記第１側で前記接触面に隣接する第１非接触面と、を有し、
    　前記接触面は、前記第１非接触面に隣接するとともに前記第１クラウニング部を形成するための第１傾斜面と、前記第２クラウニング部を形成するための第２傾斜面と、を有し、
    　前記第１非接触面と前記第１傾斜面との境界を第１境界円とし、前記第１境界円を含む仮想平面を第１境界面とし、前記第１傾斜面と前記第２傾斜面との境界を第２境界円とし、
    　前記砥石の中心軸を含む断面において、前記第２境界円上の前記第２傾斜面に対する接線を第１接線とし、
    　前記第２傾斜面を前記第２境界円よりも軸方向の第１側へ延長した仮想円すい面であって母線が前記第１接線に沿う前記仮想円すい面を、第１円すい面としたとき、
    　前記第１境界面と前記第１円すい面とが交差する第１交差円の半径と、前記第１境界円の半径と、の差が３μｍ以上、２０μｍ以下である
    軸受用ころの製造方法。     A method for manufacturing bearing rollers, the method comprising:
    The outer circumferential surface of the rough-formed product of the bearing roller includes a first rough-formed product chamfer and a surface to be polished, which are arranged in order from the first side to the second side in the axial direction of the rough-formed product. have,
    The outer circumferential surface of the bearing roller includes a first chamfered portion, a first crowning portion, and a second crowning portion that are arranged in order from the first side to the second side in the axial direction of the bearing roller. have,
    A grindstone is brought into contact with the surface to be polished, and the first crowning part and the second crowning part are formed on the surface to be polished while leaving the first chamfered part as the first chamfered part. , comprising a polishing step of obtaining the bearing roller from the rough-shaped product,
    The grindstone has a contact surface that contacts the rough-shaped product, and a first non-contact surface that is adjacent to the contact surface on the first side of the rough-shaped product,
    The contact surface has a first inclined surface adjacent to the first non-contact surface and for forming the first crowning part, and a second inclined surface for forming the second crowning part. ,
    A boundary between the first non-contact surface and the first sloped surface is a first boundary circle, a virtual plane including the first boundary circle is a first boundary surface, and the first slope and the second slope Let the boundary be the second boundary circle,
    In a cross section including the central axis of the grindstone, a tangent to the second inclined surface on the second boundary circle is a first tangent,
    When the virtual conical surface is a virtual conical surface in which the second inclined surface is extended toward the first side in the axial direction from the second boundary circle, and the generating line is along the first tangent line, the virtual conical surface is a first conical surface,
    A method for manufacturing a bearing roller, wherein a difference between a radius of a first intersecting circle where the first boundary surface and the first conical surface intersect and a radius of the first boundary circle is 3 μm or more and 20 μm or less.
  2. 　前記軸受用ころの粗形品の外周面は、前記被研磨面の軸方向の第２側に隣接する第２粗形品面取り部をさらに有し、
    　前記軸受用ころの外周面は、前記軸受用ころの軸方向の第２側から第１側へ向かって順番に並ぶ、第２面取り部と、第３クラウニング部と、前記第３クラウニング部と前記平坦部との間に位置する第４クラウニング部と、を有し、
    　前記研磨工程では、前記第２粗形品面取り部を前記第２面取り部として残しつつ、前記第１クラウニング部、及び前記第２クラウニング部に加えて、前記第３クラウニング部、及び前記第４クラウニング部を前記被研磨面に形成し、
    　前記砥石は、前記粗形品の前記第２側で前記接触面に隣接する第２非接触面をさらに有し、
    　前記接触面は、前記第２非接触面に隣接するとともに前記第３クラウニング部を形成するための第３傾斜面と、前記第４クラウニング部を形成するための第４傾斜面と、をさらに有し、
    　前記第２非接触面と前記第３傾斜面との境界を第３境界円とし、前記第３境界円を含む仮想平面を第２境界面とし、前記第３傾斜面と前記第４傾斜面との境界を第４境界円とし、
    　前記砥石の中心軸を含む断面において、前記第４境界円上の前記第４傾斜面に対する接線を第２接線とし、
    　前記第４傾斜面を前記第４境界円よりも軸方向の第２側へ延長した仮想円すい面であって母線が前記第２接線に沿う前記仮想円すい面を、第２円すい面としたとき、
    　前記第２境界面と前記第２円すい面とが交差する第２交差円の半径と、前記第３境界円の半径と、の差が３μｍ以上、２０μｍ以下である
    請求項１に記載の軸受用ころの製造方法。     The outer peripheral surface of the rough-shaped product of the bearing roller further has a second rough-shaped product chamfered portion adjacent to the second side in the axial direction of the surface to be polished,
    The outer circumferential surface of the bearing roller includes a second chamfered portion, a third crowning portion, the third crowning portion, and the third crowning portion, which are arranged in order from the second side to the first side in the axial direction of the bearing roller. a fourth crowning part located between the flat part;
    In the polishing step, in addition to the first crowning part and the second crowning part, the third crowning part and the fourth crowning part are removed while leaving the second chamfered part as the second chamfered part. forming a part on the surface to be polished;
    The grindstone further has a second non-contact surface adjacent to the contact surface on the second side of the rough-shaped article,
    The contact surface further includes a third inclined surface adjacent to the second non-contact surface and for forming the third crowning part, and a fourth inclined surface for forming the fourth crowning part. death,
    A boundary between the second non-contact surface and the third inclined surface is a third boundary circle, a virtual plane including the third boundary circle is a second boundary surface, and the third slope and the fourth slope Let the boundary be the fourth boundary circle,
    In a cross section including the central axis of the grindstone, a tangent to the fourth inclined surface on the fourth boundary circle is a second tangent,
    When the virtual conical surface is a virtual conical surface in which the fourth inclined surface is extended toward the second side in the axial direction from the fourth boundary circle, and the generating line is along the second tangent line, the virtual conical surface is a second conical surface,
    The bearing according to claim 1, wherein a difference between a radius of a second intersecting circle where the second boundary surface and the second conical surface intersect and a radius of the third boundary circle is 3 μm or more and 20 μm or less. Roller manufacturing method.
  3. 　前記軸受用ころの外周面は、前記第２クラウニング部の前記軸受用ころの軸方向の第２側で前記第２クラウニング部に隣接する円筒部をさらに有し、
    　前記接触面は、前記第２傾斜面に隣接するとともに前記円筒部を形成するための円筒面をさらに有し、
    　前記第２傾斜面と前記円筒面との境界を第５境界円とし、
    　前記第１境界円と前記第２境界円との間の軸方向の距離を第１間隔、前記第１境界円と前記第５境界円との軸方向の距離を第２間隔とするとき、
    　前記第２間隔に対する前記第１間隔の割合は、１／２０以上、１／２以下である
    請求項１に記載の軸受用ころの製造方法。
          The outer circumferential surface of the bearing roller further includes a cylindrical part adjacent to the second crowning part on a second side of the second crowning part in the axial direction of the bearing roller,
    The contact surface further includes a cylindrical surface adjacent to the second inclined surface and forming the cylindrical portion,
    The boundary between the second inclined surface and the cylindrical surface is a fifth boundary circle,
    When the axial distance between the first boundary circle and the second boundary circle is a first interval, and the axial distance between the first boundary circle and the fifth boundary circle is a second interval,
    The method for manufacturing bearing rollers according to claim 1, wherein a ratio of the first interval to the second interval is 1/20 or more and 1/2 or less.
PCT/JP2022/023407 2022-06-10 2022-06-10 Method of manufacturing rollers for bearings WO2023238364A1 (en)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2010001706A1 (en) * 2008-07-01 2010-01-07 Ntn株式会社 Bearing roller, bearing, and bearing roller processing method
WO2016133211A1 (en) * 2015-02-20 2016-08-25 Ntn株式会社 Silicon nitride roller, method for manufacturing silicon nitride roller, and method for inspecting silicon nitride roller
WO2017086120A1 (en) * 2015-11-18 2017-05-26 Ntn株式会社 Method for superfinishing bearing roller, and device for superfinishing bearing roller
JP2021105451A (en) * 2017-03-28 2021-07-26 Ntn株式会社 Tapered roller bearing

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2010001706A1 (en) * 2008-07-01 2010-01-07 Ntn株式会社 Bearing roller, bearing, and bearing roller processing method
WO2016133211A1 (en) * 2015-02-20 2016-08-25 Ntn株式会社 Silicon nitride roller, method for manufacturing silicon nitride roller, and method for inspecting silicon nitride roller
WO2017086120A1 (en) * 2015-11-18 2017-05-26 Ntn株式会社 Method for superfinishing bearing roller, and device for superfinishing bearing roller
JP2021105451A (en) * 2017-03-28 2021-07-26 Ntn株式会社 Tapered roller bearing

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