Bearing ring and method of manufacturing the same, rolling bearing and method of manufacturing the same, vehicle and method of manufacturing the same, and mechanical apparatus and method of manufacturing the same

Abstract

To provide a method for manufacturing a bearing ring capable of preventing the formation of an undesirable deteriorated layer.SOLUTION: While a second intermediate member 26 obtained by performing turning and heat treatment on a metal member is rotated, copying is performed by pressing a cutting tool (turning tool) 20 against a connection portion between the outer ring raceway 5 and the rib face 6, which is a portion of the surface of the second intermediate member 26 where a copied surface is to be formed, and moving the cutting tool 20 along the generatrix shape of the inner surface of the clearance groove 9 to be formed.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a bearing ring and a manufacturing method thereof, a rolling bearing and a manufacturing method thereof, a vehicle and a manufacturing method thereof, and a mechanical device and a manufacturing method thereof. [Background technology]

[0002] Rolling bearings such as ball bearings and roller bearings are incorporated into the rotational support parts of vehicles and various mechanical devices. A rolling bearing includes, for example, an outer ring having an outer ring raceway on its inner peripheral surface, an inner ring having an inner ring raceway on its outer peripheral surface, and a plurality of rolling elements arranged between the outer ring raceway and the inner ring raceway.

[0003] The outer ring and / or inner ring that make up a radial cylindrical roller bearing, which is a type of rolling bearing, has a raceway surface (inner ring raceway or outer ring raceway) that comes into rolling contact with the rollers, a rib surface that faces the end face of the roller and restricts the movement of the roller, and a relief groove formed around the entire circumference at the connection between the raceway surface and the rib surface, as described, for example, in JP 2014-101896 A.

[0004] As described in JP 2009-279611 A, for example, raceways such as inner and outer rings are manufactured by forging a metal material (billet) to form a cylindrical intermediate member, and then subjecting the intermediate member to machining such as cutting and grinding, and heat treatment. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-101896 [Patent Document 2] Japanese Patent Application Laid-Open No. 2009-279611 Summary of the Invention [Problem to be solved by the invention]

[0006] The relief grooves of the outer ring and / or inner ring that make up a radial cylindrical roller bearing can be formed, for example, by machining and heat treating an intermediate member obtained by forging a metal material, and then by plunge cutting, in which the cutting edge of a cutting tool (turning tool) is cut perpendicular to the tangent direction of the connection portion between the raceway surface and the flange surface.

[0007] However, when the relief groove is formed by plunge cutting, the contact area between the intermediate part and the cutting tool increases, resulting in increased heat generation at these contact points. Furthermore, plunge cutting increases the removal volume (cutting amount), which also increases the amount of heat generated by brittle fracture. As a result, a relatively brittle thermally altered layer may form on the surface of the relief groove. If a thermally altered layer forms at the connection between the raceway surface and the rib surface, where stress tends to concentrate, damage such as cracks may occur starting from the connection.

[0008] This problem is not limited to the relief groove formed at the connection between the raceway surface and the flange surface, but can also occur in chamfered portions, raceway surfaces, and other areas where a thermally altered layer may be formed during machining.

[0009] An object of the present disclosure is to provide a method for manufacturing a bearing ring that can prevent the formation of an undesirable thermally altered layer. [Means for solving the problem]

[0010] The bearing ring that is the target of the method for manufacturing a bearing ring according to one aspect of the present disclosure has a copy-machined surface on a portion of its surface over the entire circumference.

[0011] A method for manufacturing a bearing ring according to one aspect of the present disclosure includes: a turning step of turning the metal member to obtain a first intermediate member having a turned surface on its surface; a heat treatment step of subjecting the first intermediate member to heat treatment to obtain a second intermediate member having a heat-treated hardened portion at least in a surface layer portion; a copy processing step of pressing a cutting tool against a portion of the surface of the second intermediate member where the copy processed surface is to be formed while rotating the second intermediate member, and moving the cutting tool along the generatrix shape of the copy processed surface to be formed, thereby performing copy processing and forming the copy processed surface; Equipped with.

[0012] In one aspect of the method for manufacturing a bearing ring according to the present disclosure, the bearing ring may have a raceway surface that comes into rolling contact with a roller, a rib surface that faces the end face of the roller and restricts movement of the roller, and a relief groove formed around the entire circumference at the connection portion between the raceway surface and the rib surface. In this case, the copy-machined surface may be constituted by the inner surface of the relief groove. That is, the relief groove may be formed by the copy machining in the copy machining step.

[0013] The method for manufacturing a bearing ring according to one aspect of the present disclosure can further include, after the copying step, a grinding step of grinding the raceway surface and / or the flange surface using a grinding wheel.

[0014] In the method for manufacturing a bearing ring according to one aspect of the present disclosure, the cutting tool may have a cutting edge angle that is smaller than the clearance groove opening angle. In this case, the cutting edge angle of the cutting tool is preferably 30% to 90% of the clearance groove opening angle, more preferably 60% to 80%, and even more preferably 65% ​​to 75%.

[0015] In one embodiment of the method for manufacturing a bearing ring of the present disclosure, the opening angle of the escape groove can be 10° or less and 90° or more, preferably 20° or more and 70° or less, more preferably 30° or more and 60° or less, and most preferably approximately 50° (50°±1°).

[0016] In the method for manufacturing a bearing ring according to one aspect of the present disclosure, the profile-machined surface can be configured by a raceway surface that comes into rolling contact with the rolling elements.

[0017] In one embodiment of the method for manufacturing a bearing ring according to the present disclosure, the copy-machined surface can be configured as a chamfer formed around the entire circumference at the connection between the axially facing side surface and the radially facing circumferential surface.

[0018] In the method for manufacturing a bearing ring according to one aspect of the present disclosure, the copying process can be performed multiple times.

[0019] In one embodiment of the method for manufacturing a bearing ring according to the present disclosure, the copying step can be performed under conditions of a cutting speed of 60 m / min to 200 m / min, a feed rate of 0.02 mm / rev to 0.3 mm / rev, and a depth of cut of 0.03 mm to 0.5 mm. The cutting speed is preferably 70 m / min to 180 m / min, and more preferably 80 m / min to 150 m / min. The feed rate is preferably 0.03 mm / rev to 0.2 mm / rev, and more preferably 0.05 mm / rev to 0.15 mm / rev. The depth of cut is preferably 0.05 mm to 0.25 mm, and more preferably 0.08 mm to 0.12 mm.

[0020] In the method for manufacturing a bearing ring according to one aspect of the present disclosure, the cutting angle of the cutting tool can be changed during the copying process.

[0021] A rolling bearing that is a target of a method for manufacturing a rolling bearing according to one aspect of the present disclosure includes: a pair of bearing rings each having a raceway surface on each of their opposing surfaces over the entire circumference and arranged coaxially with each other; a plurality of rolling elements disposed between the raceway surfaces of the pair of raceways; Equipped with.

[0022] In a method for manufacturing a rolling bearing according to an aspect of the present disclosure, at least one of the pair of bearing rings is manufactured by the method for manufacturing a bearing ring according to an aspect of the present disclosure.

[0023] A method for manufacturing a vehicle according to one aspect of the present disclosure is a method for manufacturing a vehicle equipped with a rolling bearing, in which the rolling bearing is manufactured by the method for manufacturing a rolling bearing according to one aspect of the present disclosure.

[0024] A method for manufacturing a mechanical device according to one aspect of the present disclosure is a method for manufacturing a mechanical device including a rolling bearing, in which the rolling bearing is manufactured by the method for manufacturing a rolling bearing according to one aspect of the present disclosure.

[0025] The bearing ring according to one aspect of the present disclosure comprises: A copy-machined surface is formed on a portion of the surface over the entire circumference, The profile-machined surface has axially or radially spaced grooves.

[0026] In this case, the grooves may be formed in a spiral or vortex shape.

[0027] The bearing ring according to one aspect of the present disclosure may have a raceway surface that comes into rolling contact with the roller, a rib surface that faces the end face of the roller and restricts movement of the roller, and a relief groove formed around the entire periphery at the connection portion between the raceway surface and the rib surface. In this case, the copy-machined surface may be constituted by the inner surface of the relief groove.

[0028] In one embodiment of the bearing ring of the present disclosure, the opening angle of the clearance groove can be 10° or less and 90° or more, preferably 20° or more and 70° or less, more preferably 30° or more and 60° or less, and most preferably approximately 50° (50°±1°).

[0029] A rolling bearing according to one aspect of the present disclosure comprises: a pair of bearing rings each having a raceway surface on each of their opposing surfaces over the entire circumference and arranged coaxially with each other; a plurality of rolling elements disposed between the raceway surfaces of the pair of raceways; Equipped with.

[0030] In particular, in the rolling bearing according to one aspect of the present disclosure, at least one of the pair of bearing rings is configured by the bearing ring according to one aspect of the present disclosure.

[0031] A vehicle according to one aspect of the present disclosure includes a rolling bearing, and the rolling bearing is configured by the rolling bearing according to one aspect of the present disclosure.

[0032] A mechanical device according to one aspect of the present disclosure includes a rolling bearing, and the rolling bearing is configured by the rolling bearing according to one aspect of the present disclosure. [Effects of the Invention]

[0033] According to the method for manufacturing a bearing ring according to one aspect of the present disclosure, the formation of an undesirable thermally altered layer can be prevented. [Brief explanation of the drawings]

[0034] [Figure 1] FIG. 1 is a partially cutaway perspective view showing an example of a rolling bearing including a raceway ring according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is an enlarged view of a portion of the copy-machined surface. [Figure 3] FIG. 3 is an enlarged cross-sectional view showing the first intermediate member (second intermediate member). [Figure 4] FIG. 4 is a partially enlarged cross-sectional view for explaining a method for forming a relief groove by copying. [Figure 5] FIG. 5 is an enlarged view showing a tip that constitutes a cutting tool. [Figure 6] FIG. 6 is a partially enlarged cross-sectional view of the chip. DETAILED DESCRIPTION OF THE INVENTION

[0035] An example of an embodiment of the present disclosure will be described with reference to Figures 1 to 6. In this example, a method for manufacturing a raceway ring according to one aspect of the present disclosure is applied to the manufacture of the outer ring 2 of an NJ-type radial cylindrical roller bearing 1 in which the outer ring 2 has two inward ribs 8 at both axial ends, and the inner ring 3 has one outward rib 16 at one axial end (the right side in Figure 1).

[0036] [Structure of radial cylindrical roller bearings] The radial cylindrical roller bearing 1 comprises a pair of raceways, an outer ring 2 and an inner ring 3, which are arranged coaxially with each other, and a plurality of rolling elements (cylindrical rollers) 4.

[0037] In the following description, with respect to the radial cylindrical roller bearing 1, the axially inner side refers to the widthwise central side of the radial cylindrical roller bearing 1, and the axially outer side refers to the widthwise outer sides (both sides) of the radial cylindrical roller bearing 1.

[0038] The outer ring 2 has an outer ring raceway 5 that is in rolling contact with the rolling surfaces of the rolling elements 4, and a flange surface 6 that closely faces or slides against the axial end surfaces of the rolling elements 4 to restrict movement of the rolling elements 4. The outer ring 2 is made of a hard metal such as medium carbon steel or bearing steel.

[0039] In this example, the outer ring 2 comprises an outer ring body 7 having a cylindrical shape and two inward flange portions 8 that protrude radially inward from both axial (widthwise) ends of the outer ring body 7 along the entire circumference.

[0040] The outer ring raceway 5 is provided on the inner peripheral surface of the outer ring body 7 in an axially intermediate portion located between two inward flange portions 8 in the axial direction. The outer ring raceway 5 is formed by a cylindrical surface centered on the central axis of the outer ring 2.

[0041] A rib surface 6 is provided on each of the axially inner surfaces of the two inward rib portions 8. That is, in this example, the outer ring 2 has two rib surfaces 6. The two rib surfaces 6 closely face or slide against end surfaces on both axial sides of the rolling elements 4, restricting axial movement of the rolling elements 4 relative to the outer ring 2. The rib surface 6 is formed by a flat surface perpendicular to the central axis of the outer ring 2.

[0042] The outer ring 2 further has a relief groove 9 formed around the entire periphery at the connection between the outer ring raceway 5 and the rib surface 6. In other words, the outer ring raceway 5 and the rib surface 6 are connected via the relief groove 9. The relief groove 9 is provided to prevent the connection between the outer ring raceway 5 and the rib surface 6 from coming into contact with the outer peripheral edge of the end of the grinding wheel when the outer ring raceway 5 and the rib surface 6 are subjected to a finishing process by grinding, thereby causing sagging at the outer peripheral edge of the end of the grinding wheel, and / or to prevent interference between the connection between the outer ring raceway 5 and the rib surface 6 and the outer peripheral edge of the end of the rolling element 4 when the radial cylindrical roller bearing 1 is in operation.

[0043] In this example, the relief grooves 9 are formed around the entire circumference at the connection between both axial ends of the outer ring raceway 5 and the radially inner ends of the two flange surfaces 6. That is, in this example, the outer ring 2 has two relief grooves 9.

[0044] However, one or both of the two relief grooves 9 may be omitted. In this case, the outer ring raceway and the flange surface are connected by a corner. The corner is configured as a chamfered portion having an arc shape or a linear generatrix shape that slopes radially outward as it moves axially inward.

[0045] In this example, the relief groove 9 has a generatrix shape that is approximately V-shaped or approximately U-shaped. The inner surface of the relief groove 9 is composed of two side surfaces 10a, 10b and one bottom surface 11, as shown in FIG.

[0046] Of the two side surfaces 10a, 10b, the side surface 10a, which is located adjacent to the axially outer side of the outer ring raceway 5, has a linear generatrice shape that slopes radially outward as it moves axially outward, and is composed of a truncated cone surface facing axially outward and radially inward.

[0047] Of the two side surfaces 10a, 10b, the other side surface 10b, which is positioned adjacent to the radially outer side of the flange surface 6, has a linear generatrice shape that slopes radially outward as it moves axially outward, and is composed of a truncated cone surface facing axially inward and radially outward.

[0048] The bottom surface 11 has an arc-shaped generatrix shape that smoothly connects the two side surfaces 10a and 10b. That is, the generatrix of one side surface 10a is formed by a straight line extending in the tangential direction at the end of the generatrix of the bottom surface 11 adjacent to one side surface 10a, and the generatrix of the other side surface 10b is formed by a straight line extending in the tangential direction at the end of the generatrix of the bottom surface 11 adjacent to the other side surface 10b.

[0049] The generatrix shape of the relief groove 9 is not limited to a substantially V-shape or a substantially U-shape, and can be any shape as long as it can prevent contact between the connecting portion between the outer ring raceway 5 and the flange surface 6 and the outer peripheral edge of the grinding wheel and / or interference with the outer peripheral edge of the rolling element 4. For example, the generatrix shape of the two side surfaces 10a, 10b can be formed by a curve such as an arc or partial ellipse, or a compound curve formed by combining multiple curves and / or straight lines with different radii of curvature. Alternatively, the generatrix shape of the relief groove 9 can be formed by a single curve such as an arc or partial ellipse.

[0050] The opening angle θ of the relief groove 9 can be 10° or more and 80° or less. The opening angle θ of the relief groove 9 is the angle between tangents at both ends of the opening of the relief groove 9 in a cross section relative to an imaginary plane including the center axis of the outer ring 2. In this example, the opening angle θ of the relief groove 9 is the angle between the generatrix lines of the two side surfaces 10a, 10b. The opening angle θ of the relief groove 9 is preferably 20° or more and 70° or less, more preferably 30° or more and 60° or less, and most preferably approximately 50° (50°±1°). In this example, the opening angle θ of the relief groove 9 is approximately 50°.

[0051] In this example, the relief groove 9 is formed by copying, which is a type of hard turning, as will be described later. Specifically, after the relief groove 9 is formed by copying at the connection portion between the outer ring raceway 5 and the flange surface 6, no machining such as grinding is performed. Therefore, the inner surface of the relief groove 9 is formed by a copying-processed surface.

[0052] As shown in Fig. 2, the copy-machined surface has creases spaced apart in the axial or radial direction. Specifically, the creases are configured in a spiral shape in the portion formed on a substantially cylindrical surface centered on the central axis of the outer ring 2, and in a whorl shape in the portion formed on a surface substantially perpendicular to the central axis of the outer ring 2. The spacing between adjacent creases is the same as the feed rate of the cutting tool (bite) 20 during copy machining.

[0053] Furthermore, the surface layer of the copy-machined surface (the inner surface of the relief groove 9) does not have, or if it does have, it is extremely thin, a thermally altered layer caused by the heat generated during the machining (copying) for forming the relief groove 9. Specifically, the thickness of the thermally altered layer present on the surface layer of the copy-machined surface is, but is not limited to, 10 μm or less, and preferably 5 μm or less.

[0054] The outer ring 2 has a heat treatment-hardened portion in at least the surface layer of its surface excluding the inner surface of the relief groove 9. The heat treatment-hardened portion may be formed only on the surface layer of the outer ring 2, or may be formed over the entire outer ring 2, including the interior. The heat treatment-hardened portion is a portion hardened by heat treatment, as described below, and has a hardness of at least Hv650, although it is not limited to this.

[0055] If the heat treatment-hardened portion is formed only on the surface layer portion of the outer ring 2, it is preferably formed over the entire surface of the outer ring 2, including the inner surface of the relief groove 9. Furthermore, if the heat treatment-hardened portion is formed only on the surface layer portion of the outer ring 2, the thickness of the heat treatment-hardened portion, i.e., the portion with a hardness of Hv650 or higher, is not limited to, but is between 0 mm and 4 mm, and preferably between more than 0 mm and 2 mm.

[0056] When the heat treatment-hardened portion is formed throughout the entire outer ring 2, including into the interior thereof, the central portion of the outer ring 2 has a hardness of at least Hv650, although this is not limited to this.

[0057] In this example, the outer ring 2 further has corners 12 formed around the entire circumference at the connection between the outer peripheral surface and the end faces on both axial sides. The corners 12 are configured as chamfers having a linear generatrix shape that slopes radially outward as it moves axially inward. However, the corners 12 can also be configured as chamfers having a substantially arc-shaped generatrix shape.

[0058] The inner ring 3 has an inner ring raceway 13 that is in rolling contact with the rolling surfaces of the rolling elements 4, and a flange surface 14 that closely faces or slides against the axial end surfaces of the rolling elements 4 to restrict axial movement of the rolling elements 4. The inner ring 3 is made of a hard metal such as medium carbon steel or bearing steel.

[0059] In this example, the inner ring 3 comprises an inner ring body 15 having a cylindrical shape and an outward flange portion 16 that protrudes radially outward from the end portion on one side (right side in Figure 1) of the inner ring body 15 in the axial direction (width direction) over the entire circumference.

[0060] The inner ring raceway 13 is provided on the outer peripheral surface of the inner ring body 15, in a portion that is offset from the outward flange portion 16 to the other axial side (the left side in FIG. 1 ). The inner ring raceway 13 is formed by a cylindrical surface centered on the central axis of the inner ring 3.

[0061] The flange surface 14 is provided on the axially inner surface (the surface on the other axial side) of the outward flange portion 16. The flange surface 14 closely faces or slides against the end surface on one axial side of the rolling element 4, restricting movement of the rolling element 4 to one axial side relative to the inner ring 3. The flange surface 14 is formed of a flat surface perpendicular to the central axis of the inner ring 3.

[0062] The inner ring 3 further has a relief groove 17 formed around the entire circumference at the connection between the inner ring raceway 13 and the flange surface 14. In other words, the inner ring raceway 13 and the flange surface 14 are connected via the relief groove 17. The generatrice shape of the relief groove 17 is not limited to this, but can be, for example, an approximately V-shape or an approximately U-shape, or a curve such as a single arc or partial ellipse.

[0063] However, the relief groove 17 can be omitted. In this case, the inner ring raceway and the flange surface are connected by a corner. The corner is configured as a chamfered portion having an arc shape or a linear generatrix shape that slopes radially outward as it goes axially outward.

[0064] In this example, the inner ring 3 further has corners 18 formed around the entire circumference at the connection between the end faces on both axial sides and the inner peripheral surface. The corners 18 are configured as chamfers having a linear generatrix shape that slopes radially outward as it extends axially outward. However, the corners 18 can also be configured as chamfers having a substantially arc-shaped generatrix shape.

[0065] The rolling elements 4 are made of cylindrical rollers having a cylindrical shape, and are arranged between the outer ring raceway 5 and the inner ring raceway 13 so that they can roll freely while being held by a cylindrical cage 19. The rolling elements 4 are made of hard metal such as bearing steel or ceramics.

[0066] The rolling surfaces provided on the outer peripheral surfaces of the rolling elements 4 are in rolling contact with the outer ring raceway 5 and the inner ring raceway 13. Furthermore, the end faces of the rolling elements 4 on one axial side closely face each other or are in sliding contact with the rib surface 6 on one axial side of the outer ring 2 and the rib surface 14 of the inner ring 3, and the end faces on the other axial side closely face each other or are in sliding contact with the rib surface 6 on the other axial side of the outer ring 2.

[0067] [Method for manufacturing outer ring] In this example, the outer ring 2 is manufactured by the method for manufacturing a bearing ring according to one aspect of the present disclosure. The method for manufacturing the outer ring 2 includes a turning step, a heat treatment step, and a copying step.

[0068] In the turning step, a metal member is turned to obtain a first intermediate member 24 having a turned surface on its surface.

[0069] The metal member has an outer shape that roughly matches the outer shape of the outer ring 2. Specifically, the metal member has an outer shape that roughly matches the outer shape of the outer ring 2, excluding the machining allowances removed in the turning, copying, and finishing processes described below. Such a metal member can be produced by forging a metal blank (billet).

[0070] The type of forging is not particularly limited. That is, the processing for forming the material into the metal member may be performed by any of cold forging, hot forging, and warm forging. However, in order to form the member with good shape precision, cold forging is preferable.

[0071] In this example, in the turning step, the metal member is turned to form the outer ring raceway 5, the flange surface 6, and the corner portion 12, thereby obtaining the first intermediate member 24. That is, in this example, the outer ring raceway 5, the flange surface 6, and the corner portion 12 form the turned surface.

[0072] In this example, no relief groove 9 is formed in the turning process. The first intermediate member 24 has a corner portion 25 at the connection between the outer ring raceway 5 and the rib surface 6, which has an arc shape or a linear generatrix shape that inclines in a direction that is more radially outward as it goes axially outward. In the first intermediate member 24, the outer ring raceway 5 and the rib surface 6 are formed so that a machining allowance is left on their respective surface layers to be removed by grinding in a finishing process, which will be described later.

[0073] Next, in the heat treatment step, the first intermediate member 24 is heat treated to obtain a second intermediate member 26 having a heat treatment-hardened portion at least on the surface layer portion. Specifically, the first intermediate member 24 is heat treated to form a heat treatment-hardened portion at least on a portion including the outer ring raceway 5 and the flange surface 6, thereby obtaining the second intermediate member 26. In other words, the outer shape of the second intermediate member 26 is the same as the outer shape of the first intermediate member 24.

[0074] The heat treatment includes quenching, and may further include tempering as necessary. Both quenching and tempering are performed by heating the first intermediate member 24 to a target temperature, holding it for a predetermined time, and then cooling it. The first intermediate member 24 may be heated by high-frequency induction heating using a coil, or may be heated using a heating furnace such as an electric furnace, a gas furnace, or a heavy oil furnace.

[0075] For example, although not limited to, when a heat treatment-hardened portion is to be formed only on the surface layer of the completed outer ring 2, heating of first intermediate member 24 can be performed by high-frequency induction heating using a coil. Furthermore, when a heat treatment-hardened portion is to be formed on the entire completed outer ring 2, including the interior thereof, heating of first intermediate member 24 can be performed using a heating furnace, although not limited to this.

[0076] The manufacturing method of the outer ring 2 can optionally include a grinding step, after the heat treatment step and before the profiling step, of surface grinding both axially outer end faces, external diameter grinding of the outer peripheral surface, internal diameter grinding of the outer ring raceway 5, and / or surface grinding of the rib surface 6. By performing the grinding step after the heat treatment step and before the profiling step, the machining accuracy of the relief groove 9 can be improved.

[0077] Next, in the copying process, while rotating the second intermediate member 26, a cutting tool (cutting tool) 20 is pressed against a corner 25 of the surface of the second intermediate member 26, which is a portion where a copying processing surface is to be formed, and copying is performed by moving the cutting tool 20 along the generatrix shape of the inner surface of the relief groove 9 to be formed, as shown by the arrow in Fig. 4. In this way, the relief groove 9 is formed.

[0078] The cutting edge of cutting tool 20 is made of a material harder than the metal material that makes up outer ring 2. Specifically, the cutting edge (chip) of cutting tool 20 can be made of a material such as ultra-high pressure sintered compact (CBN), ceramic, or K-type cemented carbide.

[0079] The cutting edge angle of the cutting tool 20, i.e., the angle φ between the two side flanks 21a, 21b, is smaller than the opening angle θ of the relief groove 9. Although the cutting edge angle φ is not limited thereto, it is preferably 30% to 90% of the opening angle θ of the relief groove 9, more preferably 60% to 80%, and even more preferably 65% ​​to 75%. If the cutting edge angle φ of the cutting tool 20 is larger than 90% of the opening angle θ of the relief groove 9, the contact area between the cutting edge of the cutting tool 20 and the inner surface of the relief groove 9 increases, which may result in excessive heat generation at the contact area. Furthermore, if the cutting edge angle φ of the cutting tool 20 is smaller than 30% of the opening angle θ of the relief groove 9, it may be difficult to ensure the durability of the cutting tool 20. Specifically, the cutting edge angle φ of the cutting tool 20 is not limited to, but can be 15° or more and 80° or less, preferably 25° or more and 70° or less, and more preferably 30° or more and 55° or less. In this example, the cutting edge angle φ of the cutting tool 20 is approximately 35°. In other words, the cutting edge angle φ of the cutting tool 20 is approximately 70% of the opening angle θ of the relief groove 9.

[0080] The width (chamfer width) W of the C-chamfered portion 23 of the cutting tool 20, provided at the corner between the side flanks 21a, 21b and the rake face 22, is not limited to, but can be 0.05 mm to 0.5 mm, preferably 0.08 mm to 0.3 mm, and more preferably 0.1 mm to 0.2 mm. If the chamfer width W is greater than 0.5 mm, the contact area between the cutting edge of the cutting tool 20 and the inner surface of the relief groove 9 increases, which can result in excessive heat generation at these contact points. Furthermore, if the chamfer width W is less than 0.05 mm, the cutting ability (sharpness) of the cutting tool 20 is likely to deteriorate, which can lead to problems such as reduced productivity of the outer ring 2.

[0081] The angle α of the C-chamfered portion 23 (the angle of the C-surface relative to the side relief surfaces 21a and 21b) is not limited to, but can be set to 10° or more and 40° or less. In this example, the angle α of the C-chamfered portion 23 is 25°.

[0082] The copy machining conditions, i.e., cutting speed, feed rate, cutting depth, and opening angle θ of the clearance groove 9, are determined appropriately based on the specifications of the cutting tool 20, the surface roughness required of the copy machined surface (inner surface of the clearance groove 9) after copy machining is completed, the magnitude of residual compressive stress to be generated on the copy machined surface after copy machining is completed, etc.

[0083] Specifically, the cutting speed (the relative speed between the second intermediate member 26, which is the workpiece, and the cutting tool 20) is not limited to, but can be set to 60 m / min or more and 200 m / min or less, preferably 70 m / min or more and 180 m / min or less, and more preferably 80 m / min or more and 150 m / min or less. If the cutting speed is faster than 200 m / min, the amount of heat generated at the contact portion between the cutting edge of the cutting tool 20 and the inner surface of the relief groove 9 may increase excessively. Also, if the cutting speed is slower than 60 m / min, the processing efficiency may decrease, which may increase the manufacturing cost.

[0084] The feed rate is not limited to, but can be 0.02 mm / rev or more and 0.3 mm / rev or less, preferably 0.03 mm / rev or more and 0.2 mm / rev or less, and more preferably 0.05 mm / rev or more and 0.15 mm / rev or less. If the feed rate is greater than 0.3 mm / rev, the surface roughness of the copy-machined surface (the inner surface of the relief groove 9) after copy machining is completed may deteriorate. If the feed rate is less than 0.02 mm / rev, the machining efficiency may decrease, which may increase manufacturing costs.

[0085] The depth of cut is not limited to, but can be 0.03 mm or more and 0.5 mm or less, preferably 0.05 mm or more and 0.25 mm or less, and more preferably 0.08 mm or more and 0.12 mm or less. If the depth of cut is greater than 0.5 mm, the amount of heat generated at the contact point between the cutting edge of the cutting tool 20 and the inner surface of the relief groove 9 may increase excessively. If the depth of cut is less than 0.03 mm, the processing efficiency may decrease, and the manufacturing cost may increase.

[0086] The opening angle θ of the relief groove 9 is not limited to, but can be 10° to 80°, preferably 20° to 70°, more preferably 30° to 60°, and most preferably approximately 50° (50°±1°). If the opening angle θ of the relief groove 9 is greater than 80°, the amount of machining required may increase, potentially increasing manufacturing costs. Furthermore, if the opening angle θ of the relief groove 9 is less than 10°, the contact area between the cutting edge of the cutting tool 20 and the inner surface of the relief groove 9 may increase, potentially resulting in excessive heat generation at these contact points.

[0087] In the copy machining process, copy machining can be performed multiple times. This allows the cutting amount (cutting depth) per time to be kept small, and the amount of heat generated at the contact portion between the cutting edge of the cutting tool 20 and the inner surface of the relief groove 9 to be kept small. This makes it more difficult for a thermally altered layer to be formed on the surface of the inner surface of the relief groove 9 due to the influence of heat generated during machining. Furthermore, by keeping the cutting amount per time small, it becomes easier to form the relief groove 9 with high precision. When copy machining is performed multiple times, the machining conditions for each time can be different or the same. However, copy machining can also be performed only once in the copy machining process.

[0088] The cutting angle of the cutting tool can also be changed during copying, making it possible to machine a variety of shapes using copying.

[0089] The copy machining can be performed, for example, using a lathe equipped with a computer-based numerical control function. Specifically, the second intermediate member 26 is held by a chuck, and the chuck is rotated to rotate the second intermediate member 26 about its central axis. Then, based on a movement command from the computer, the cutting tool 20 is moved relative to the second intermediate member 26 so as to follow the generatrices of the inner surface of the relief groove 9, thereby performing the copy machining.

[0090] When carrying out the method for manufacturing a bearing ring according to one aspect of the present disclosure, a copying step may be carried out in which the approximate shape of the clearance groove is formed by plunge machining, and then copying is performed to form a copying processed surface.

[0091] In the method of manufacturing outer ring 2 of this example, relief groove 9 is formed by copying, which reduces the contact area between the cutting edge of cutting tool 20 and the inner surface of relief groove 9, thereby reducing the amount of heat generated at these contact points. This prevents a relatively brittle thermally altered layer from forming on the surface layer of the inner surface of relief groove 9, effectively preventing fatigue fracture originating from relief groove 9 during operation of radial cylindrical roller bearing 1.

[0092] The copying process for forming the relief groove 9 is performed by rotating the second intermediate member 26, pressing the cutting tool 20 against a corner 25 of the second intermediate member 26 that is present at the connection between the outer ring raceway 5 and the rib surface 6, and moving the cutting tool 20 relative to the second intermediate member 26 so as to follow the generatrices of the inner surface of the relief groove 9. Therefore, sufficient compressive residual stress can be imparted to the surface layer of the relief groove 9, improving the strength of the surface layer of the relief groove 9 where stress is likely to concentrate during operation of the radial cylindrical roller bearing 1. From this perspective as well, the occurrence of fatigue fracture originating from the relief groove 9 can be effectively prevented.

[0093] The manufacturing method of the outer ring 2 in this example further includes, after the profiling step, a grinding step in which a grinding wheel is used to grind the outer ring raceway 5 and the rib surface 6. Note that in the grinding step, the relief groove 9 formed at the connection portion between the outer ring raceway 5 and the rib surface 6 is not ground.

[0094] The grinding of the outer ring raceway 5 and the grinding of the flange surface 6 can be carried out simultaneously or sequentially.

[0095] In this example, the relief groove 9 is formed at the connection portion between the outer ring raceway 5 and the flange surface 6, so that when grinding the outer ring raceway 5 and the flange surface 6, the outer peripheral edge of the end of the grinding wheel can be prevented from contacting the connection portion between the outer ring raceway 5 and the flange surface 6. This makes it possible to prevent sagging from occurring at the outer peripheral edge of the end of the grinding wheel.

[0096] When implementing the present disclosure, instead of or in addition to the inner surface of the relief groove 9, the chamfered portions that form the outer ring raceway 5 and the corners 12, and / or the chamfered portions that form the corners 25 formed at the connection between the outer ring raceway 5 and the flange surface 6 can be formed by a copy-machined surface instead of the relief groove 9. In other words, instead of or in addition to the relief groove 9, the chamfered portions that form the outer ring raceway 5 and the corners 12, and / or the chamfered portions that form the corners can be formed by copy machining.

[0097] Furthermore, the raceway ring and the manufacturing method thereof according to one embodiment of the present disclosure are not limited to the outer ring 2 of the NJ-type radial cylindrical roller bearing 1, but can be applied to raceways of various rolling bearings and the manufacturing thereof.

[0098] For example, the bearing ring and manufacturing method thereof according to one embodiment of the present disclosure can be applied to the inner ring 3 instead of or in addition to the outer ring 2. In this case, at least one of the inner ring raceway 13, the relief groove 17 or the corner portion, and the angular portion 18 is formed by copying.

[0099] The raceway ring and manufacturing method thereof according to one embodiment of the present disclosure is not limited to the outer ring and / or inner ring of an NJ-type radial cylindrical roller bearing, but can also be applied to the outer ring and / or inner ring of a cylindrical roller bearing, such as an NF-type in which the outer ring has one inward rib portion and the inner ring has two outward ribs, an NU-type in which the outer ring has two inward ribs and the inner ring has no outward ribs, or an N-type in which the inner ring has two outward ribs and the outer ring has no inward ribs, and to the manufacture of such bearings.

[0100] The bearing ring and manufacturing method thereof according to one embodiment of the present disclosure can be applied not only to radial cylindrical roller bearings, but also to outer rings and / or inner rings of radial rolling bearings such as radial tapered roller bearings and radial ball bearings, or bearing rings of thrust rolling bearings such as thrust cylindrical roller bearings, thrust tapered roller bearings and thrust ball bearings, and to the manufacture of such bearings.

[0101] The raceway ring and its manufacturing method according to one embodiment of the present disclosure are not limited to single-row rolling bearings with one row of rolling elements, but can also be applied to raceways of rolling bearings with multiple rows of rolling elements and their manufacturing methods.

[0102] A rolling bearing including the raceway ring and the manufacturing method thereof according to one embodiment of the present disclosure can be provided with a seal device for preventing foreign matter from entering the rolling element installation space between the pair of raceways and / or preventing lubricant sealed in the rolling element installation space from leaking into the external space. In this case, a locking groove for locking the seal device and / or a seal groove for sliding contact or closely opposing the tip of the seal device can be formed by copying.

[0103] The locking groove and seal groove are roughly formed in the forging process and / or turning process prior to the copy machining process, but the heat treatment process can cause thermal deformation and loss of roundness. If the locking groove and seal groove loses roundness, the sliding pressure or gap between the tip of the sealing device and the seal groove becomes uneven in the circumferential direction, resulting in reduced sealing performance. If the locking groove and / or seal groove are formed by copy machining in the copy machining process after the heat treatment process, good roundness can be ensured, and good sealing performance can be ensured.

[0104] A rolling bearing including a bearing ring that is the subject of the bearing ring and the manufacturing method thereof according to one embodiment of the present disclosure is used by being incorporated into a rotation support part of a vehicle or mechanical device. [Explanation of symbols]

[0105] 1 Radial cylindrical roller bearing 2 outer ring 3. Inner circle 4 Rolling elements (cylindrical rollers) 5 Outer raceway 6 Tsuba surface 7 Outer ring body 8 Inward flange 9 Relief groove 10a, 10b side 11 Bottom 12 Corner 13 Inner raceway 14 Tsuba-men 15 Inner ring body 16 Outward flange 17 Relief groove 18 Corner 19 Cage 20 cutting tools 21a, 21b Side relief 22 Rake face 23 C chamfered part 24 First intermediate member 25 Corner 26 Second intermediate member

Claims

1. A method for manufacturing a bearing ring having a copy-machined surface on a part of its surface over the entire circumference, a turning step of turning the metal member to obtain a first intermediate member having a turned surface on its surface; a heat treatment step of subjecting the first intermediate member to heat treatment to obtain a second intermediate member having a heat-treated hardened portion at least in a surface layer portion thereof; a copy processing step of pressing a cutting tool against a portion of the surface of the second intermediate member where the copy processed surface is to be formed while rotating the second intermediate member, and moving the cutting tool along the generatrix shape of the copy processed surface to be formed, thereby performing copy processing and forming the copy processed surface; A method for manufacturing a bearing ring, comprising:

2. the raceway ring has a raceway surface that comes into rolling contact with the roller, a rib surface that faces the end face of the roller and restricts movement of the roller, and a relief groove formed around the entire periphery at a connection portion between the raceway surface and the rib surface, The copy-machined surface is formed by the inner surface of the relief groove. The method for manufacturing the bearing ring according to claim 1 .

3. The method further includes a grinding step of grinding the raceway surface and / or the flange surface using a grinding wheel after the profiling step. The method for manufacturing the bearing ring according to claim 2 .

4. The cutting edge angle of the cutting tool is smaller than the opening angle of the relief groove. The method for manufacturing the bearing ring according to claim 2 .

5. The opening angle of the relief groove is about 50°. The method for manufacturing the bearing ring according to claim 2 .

6. The profile-machined surface is constituted by a raceway surface that comes into rolling contact with the rolling element. The method for manufacturing the bearing ring according to claim 1 .

7. The copy-machined surface is configured by a chamfered portion formed around the entire periphery at a connection portion between a side surface facing in the axial direction and a peripheral surface facing in the radial direction. The method for manufacturing the bearing ring according to claim 1 .

8. In the copying process, the copying is performed a plurality of times. The method for manufacturing the bearing ring according to claim 1 .

9. In the copying step, the copying is performed under the conditions of a cutting speed of 60 m / min or more and 200 m / min or less, a feed rate of 0.02 mm / rev or more and 0.3 mm / rev or less, and a cutting depth of 0.03 mm or more and 0.5 mm or less. The method for manufacturing the bearing ring according to claim 1 .

10. changing the cutting angle of the cutting tool during the copying process; The method for manufacturing the bearing ring according to claim 1 .

11. a pair of bearing rings each having a raceway surface on each of opposing surfaces over the entire circumference and arranged coaxially with each other; a plurality of rolling elements disposed between the raceway surfaces of the pair of raceways; A method for manufacturing a rolling bearing, comprising: At least one of the pair of bearing rings is manufactured by the bearing ring manufacturing method according to any one of claims 1 to 10. Manufacturing method for rolling bearings.

12. A method for manufacturing a vehicle equipped with a rolling bearing, comprising: A method for manufacturing a vehicle, comprising manufacturing the rolling bearing by the method for manufacturing a rolling bearing according to claim 11.

13. A method for manufacturing a mechanical device equipped with a rolling bearing, comprising: A method for manufacturing a mechanical device, comprising manufacturing the rolling bearing by the method for manufacturing a rolling bearing according to claim 11.

14. A copy-machined surface is formed on a portion of the surface over the entire circumference, The profile-machined surface has streaks spaced apart in the axial or radial direction. Orbital ring.

15. The streaks are formed in a spiral or spiral shape.

15. A bearing ring according to claim 14.

16. the bearing has a raceway surface that comes into rolling contact with a roller, a flange surface that faces the end face of the roller and restricts movement of the roller, and a relief groove formed around the entire periphery at a connection portion between the raceway surface and the flange surface, 15. The bearing ring according to claim 14, wherein the profile-machined surface is formed by the inner surface of the relief groove.

17. 17. The race of claim 16, wherein the relief groove has an opening angle of approximately 50 degrees.

18. a pair of bearing rings each having a raceway surface on each of opposing surfaces over the entire circumference and arranged coaxially with each other; a plurality of rolling elements disposed between the raceway surfaces of the pair of raceways; Equipped with At least one of the pair of bearing rings is configured by the bearing ring according to any one of claims 14 to 17. Rolling bearing.

19. Equipped with rolling bearings, The rolling bearing is constituted by the rolling bearing according to claim 18. vehicle.

20. Equipped with rolling bearings, The rolling bearing is constituted by the rolling bearing according to claim 18. Mechanical equipment.

Images