Roller bearing

Abstract

The present invention relates to a roller bearing which can more reliably prevent the occurrence of seizure when a shell-shaped outer ring is assembled to a housing. This roller bearing is provided with: a ring-shaped shell-shaped outer ring (10); a retainer (20) that is inserted into the shell-shaped outer ring (10); and a roller (30) held by the cage (20), the shell-shaped outer ring (10) being provided with: an outer ring section (13) that forms a raceway surface (15) that faces the rolling surface (31) of the roller (30); a first flange part (11) protruding from one axial end of the outer ring part (13) to the inner diameter side; a second flange part (12) protruding toward the inner diameter side from the other axial end of the outer ring part (13); and bent sections (14) that are provided between the outer ring section (13) and the first flange section (11) and between the outer ring section (11) and the second flange section (12), and that set the inner diameter (r11) of the inner diameter-side end (11a) of the first flange section (11) to 80% or more but less than 95% of the outer diameter (r20) of the maximum diameter section of the cage (20).

Description

Technical Field

[0001] The present invention relates to a roller bearing and a housing-shaped outer ring for the roller bearing. Background Art

[0002] As a roller bearing, there is a bearing having a housing-shaped outer ring. Such a roller bearing includes: a housing-shaped outer ring formed of a metal plate-like member; a retainer fitted inside the inner diameter of the housing-shaped outer ring; and rollers as rolling elements held by the retainer. The housing-shaped outer ring includes: a cylindrical outer ring portion that forms a raceway surface facing the rolling surface of the rolling elements; and flange portions that project inward in the diameter direction at both axial ends of the outer ring portion.

[0003] However, in the recent automotive industry, from the viewpoint of improving fuel efficiency, in order to achieve vehicle lightening, the opportunity to use light alloy materials such as aluminum has increased. Along with this, as the material of the housing (axle box) that supports the bearing, the use of light alloy materials such as aluminum is also relatively common. In a housing made of a light alloy, compared with a housing made of steel (iron), the risk of galling of the housing-shaped outer ring increases. Therefore, in the housing-shaped outer ring of Patent Document 1, a tapered portion is provided on the outer peripheral surface of one axial end portion of the outer ring portion, the tapered portion gradually decreases in outer diameter from the inner side in the axial direction toward the outer side in the axial direction, and the taper angle of the tapered portion with respect to the axis is set in the range of 0.5 degrees or more and less than 5 degrees to prevent the occurrence of galling.

[0004] In addition, in the housing-shaped outer ring of Patent Document 2, a bent R portion is interposed between the outer surfaces of the ridge line portions between the outer ring portion and the flange portion, and a connecting portion that smoothly connects the tapered portion on the outer peripheral surface of the outer ring portion and the bent R portion is provided.

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2023-43353

[0006] Patent Document 2: Japanese Unexamined Patent Application Publication No. 2023-114019

[0007] As an advantage of a roller bearing using a housing-shaped outer ring, compared with other types of bearings such as ball bearings, it can be cited that it can be applied in a compact size. In particular, in recent years in electric vehicles, the demand for a power device “eAxle” that integrates a speed reducer including an inverter, a motor, and a differential is increasing. In such a power device, in order to achieve miniaturization of the device while ensuring the load capacity, there is also a case where a housing-shaped bearing with a narrower bearing width and an increased outer diameter is adopted.

[0008] However, as described above, a roller bearing using a shell-shaped outer ring is prone to galling with respect to a housing made of light alloy. In addition, the shell-shaped outer ring is formed by stamping. Therefore, with the increase in the diameter of the bearing, there is a concern that the machining accuracy of the shell-shaped outer ring deteriorates. In addition, due to the increase in the fitting area of the shell-shaped outer ring with respect to the housing, an increase in its press-fitting force is feared. If galling or an excessive press-fitting force occurs, a situation may occur where the flange portion of the shell-shaped outer ring is deformed and clamps internal components, etc.

[0009] According to the shell-shaped outer rings of Patent Documents 1 and 2, galling during press-fitting can be prevented. However, if the diameter of the shell-shaped outer ring increases, the force required for press-fitting into the housing becomes larger. Therefore, a technique for more reliably preventing galling during press-fitting is required. Summary of the Invention

[0010] Therefore, an object of the present invention is to more reliably prevent the occurrence of galling when assembling a roller bearing having a shell-shaped outer ring into a housing.

[0011] To solve the above problems, the present invention employs a roller bearing, which includes: a shell-shaped outer ring, which is annular; a retainer, which is fitted into the shell-shaped outer ring; and rollers, which are held by the retainer. The shell-shaped outer ring includes: an outer ring portion, which forms a raceway surface facing the rolling surface of the rollers; a first flange portion, which protrudes from one axial end of the outer ring portion toward the inner diameter side; a second flange portion, which protrudes from the other axial end of the outer ring portion toward the inner diameter side; and a bent portion, which is provided between the outer ring portion and the first flange portion and between the outer ring portion and the second flange portion, and the inner diameter of the inner diameter side end of the first flange portion is set to be 80% or more and less than 95% of the outer diameter of the maximum diameter portion of the retainer (Structure 1).

[0012] The following structure can be adopted: based on Structure 1, the shell-shaped outer ring is press-fitted into the inner diameter of the housing, and the first flange portion is set to the front end side when press-fitting into the inner diameter of the housing (Structure 2).

[0013] The following structure can be adopted: based on Structure 1 or Structure 2, the plate thickness of the first flange portion is set to be 45% or more and less than 70% of the plate thickness of the outer ring portion (Structure 3).

[0014] In addition, the following structure can be adopted: based on Structure 1, Structure 2, or Structure 3, a plate thickness changing portion is provided at the end on the axial one end side of the outer ring portion, the plate thickness of the plate thickness changing portion gradually decreases from the plate thickness of the outer ring portion to the plate thickness of the first flange portion, and the inner surface of the plate thickness changing portion is an inclined surface that faces the outer diameter side at an angle of 25° or more and less than 35° with respect to the axial direction as it approaches the first flange portion (Structure 4).

[0015] In addition, the following structure can be adopted: based on any one of Structures 1 to 4, the hardness of at least the first flange portion of the shell-shaped outer ring is 600 HV or less (Structure 5).

[0016] In addition, the following structure can be adopted: based on any one of Structures 1 to 5, between the outer diameter Ra at the axially other end of the range facing the rolling surface in the outer ring portion, the outer diameter Rb at the axial center of the range facing the rolling surface in the outer ring portion, and the outer diameter Rc at the axially one end of the range facing the rolling surface in the outer ring portion, Rb > Ra ≥ Rc or Rb > Rc > Ra holds (Structure 6).

[0017] According to the present invention, when assembling a roller bearing having a shell-shaped outer ring into a housing, the occurrence of seizure can be more reliably prevented. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a longitudinal sectional view showing one embodiment of the present invention.

[0019] Figure 2A is Figure 1 an enlarged view of the main part of

[0020] Figure 2B is Figure 2A an enlarged view of the main part of

[0021] Figure 3 is a longitudinal sectional view showing a state where the roller bearing is pressed into the housing.

[0022] Figure 4 is Figure 3 a sectional view taken along line IV-IV of

[0023] REFERENCE SIGNS LIST

[0024] 1... roller bearing (bearing); 10... shell-shaped outer ring; 11... first flange portion; 12... second flange portion; 13... outer ring portion; 14... bent portion; 15... raceway surface; 16... plate thickness change portion; 16a... inner surface (inclined surface); 20... retainer; 30... roller; 31... rolling surface; r11... inner diameter at the inner diameter side end; r20... outer diameter at the maximum diameter portion; t11, t13... plate thickness; R, Ra, Rb, Rc... outer diameter. DETAILED DESCRIPTION OF THE INVENTION

[0025] Embodiments of the present invention will be described based on the drawings. Figure 1 is a longitudinal sectional view of the roller bearing 1 of the present embodiment. Figure 2A and Figure 2B is a detailed view of the shell-shaped outer ring 10 used in the roller bearing 1. Figure 3It is a cross-sectional view showing the state in which the roller bearing 1 is pressed and fixed in the housing H.

[0026] The roller bearing 1 includes: a shell-shaped outer ring 10, which is annular; a cage 20, which is fitted into the shell-shaped outer ring 10; and cylindrical rollers 30, which are held by the cage 20. In the embodiment, as the rollers 30, needle rollers having a length in the cylindrical axis direction longer than the diameter (for example, the length is about 3 times or more and less than 10 times the diameter) are used. In the embodiment, a large roller bearing 1 having an outer diameter of φ60 or more and 100φ or less and used in the power unit "eAxle" of an electric vehicle is envisioned.

[0027] The cage 20 includes paired ring portions 21, 21, and a plurality of column portions 22 that axially connect between the ring portions 21, 21. The space between the circumferentially adjacent column portions 22, 22 becomes a pocket portion for holding the rollers 30. The rollers 30 are held by roller stopper portions (not shown) protruding from the column portions 22 so as not to fall off.

[0028] The shell-shaped outer ring 10 includes: an outer ring portion 13, which forms a raceway surface 15 opposing the rolling surface 31 of the roller 30; a first flange portion 11, which protrudes from one axial end of the outer ring portion 13 toward the inner diameter side; and a second flange portion 12, which protrudes from the other axial end of the outer ring portion 13 toward the inner diameter side. In addition, the first flange portion 11 and the second flange portion 12 each include a bent portion 14 connected to the outer ring portion 13.

[0029] The shell-shaped outer ring 10 is formed by bending a metal cylindrical member. The bent portion 14 on the other axial end side (the second flange portion 12 side) is formed by stamping the end portion of the cylindrical member. The bent portion 14 on one axial end side (the first flange portion 11 side) is formed by bending after the cage 20 and the rollers 30 are inserted into the inside of the outer ring portion 13. Hereinafter, the processing of the bent portion 14 on the other axial end side is referred to as pre-bending processing, and the processing of the bent portion 14 on one axial end side is referred to as post-bending processing.

[0030] The cage 20 and the rollers 30 are inserted into the inside of the shell-shaped outer ring 10 in which the second flange portion 12 is formed by pre-bending processing, and the first flange portion 11 is formed by post-bending processing, thereby becoming a state in which the cage 20 and the rollers 30 are held inside the outer ring portion 13, and the roller bearing 1 is constituted. In addition, the roller bearing 1 is pressed and fixed to the inner diameter of the housing H having a hole with a circular cross-section. At this time, a press-fit margin of about 40 to 350 μm is set in terms of diameter difference. Further, a shaft (not shown) is inserted through the inside of the circumferentially arranged rollers 30, that is, on the axis O side of the roller bearing 1, and the shaft is supported so as to be able to rotate relative to the housing H about the axis.

[0031] In an embodiment, as the housing H, a housing for supporting a roller bearing 1 used in a power unit "eAxle" of an electric vehicle is envisioned, but the housing H can also be a component other than the housing in such an "eAxle". The housing H is made of a light metal mainly composed of aluminum or other light metals other than aluminum. For the housing-shaped outer ring 10, when being press-fitted into the inner diameter of the housing H, the first flange portion 11 side of the housing-shaped outer ring 10 is press-fitted first. That is, the first flange portion 11 side is set as the front end side during press-fitting, and the second flange portion 12 side is set as the rear end side during press-fitting.

[0032] The housing-shaped outer ring 10 is formed by cold rolling a carbon steel or stainless steel for mechanical structures. For example, SPC, SCM, SUS, etc. can be cited. The plate thickness t13 of the outer ring portion 13 is, for example, 0.5 or more and less than 2.5 mm. In addition, the inner surface of the hole of the housing H in contact with the outer surface 17 of the outer ring portion 13 is processed to be below a specified average roughness.

[0033] As Figure 1 shown, the outer diameter r20 of the maximum diameter portion of the cage 20 is larger than the inner diameter r11 of the inner diameter side end 11a of the first flange portion 11, and also larger than the inner diameter r12 of the inner diameter side end 12a of the second flange portion 12. Thus, the axial movement of the cage 20 is restricted by the first flange portion 11 and the second flange portion 12. In addition, in Figure 1 the outer diameter of the housing-shaped outer ring 10 is denoted by the reference numeral R in the drawings.

[0034] In addition, the inner diameter r11 of the inner diameter side end 11a of the first flange portion 11 is set to be 80% or more and less than 95% of the outer diameter r20 of the maximum diameter portion of the cage 20. Thus, an effect of preventing seizure during press-fitting into the housing H can be expected. That is, if the press-fitting force of the roller bearing 1 relative to the housing H is too large, seizure is likely to occur in the first flange portion 11 of the housing-shaped outer ring 10 and the housing H on the target side. However, by expanding the inner diameter of the first flange portion 11, which is the front end side during press-fitting, compared with the past, the rigidity of the flange portion is reduced, and as a result, smooth press-fitting is achieved by reducing the press-fitting force.

[0035] Here, if the ratio of the inner diameter r11 of the inner diameter side end 11a of the first flange portion 11 to the outer diameter r20 of the maximum diameter portion of the cage 20 is less than 80%, the rigidity of the cup-shaped outer ring 10 becomes high, and there is a tendency for seizure to easily occur. In addition, when the roller bearing 1 is oil-lubricated, there may also be a problem of hindering the smooth outflow and inflow of oil to the inside of the cup-shaped outer ring 10. On the contrary, if this ratio becomes 95% or more, when the cage 20 is tilted (when the axis of the cage 20 is tilted with respect to the axis of the cup-shaped outer ring 10), depending on the usage conditions, there may also be problems such as the end portion of the cage 20 being hooked on the inner diameter side end of the cup-shaped outer ring 10 or the cage 20 falling off. In these respects, it is also preferable that the ratio of the inner diameter r11 of the inner diameter side end 11a of the first flange portion 11 to the outer diameter r20 of the maximum diameter portion of the cage 20 is set to 80% or more and less than 95%.

[0036] In addition, the first flange portion 11 stands up from one axial end of the cylindrical outer ring portion 13 toward the inner diameter side. For the outer ring portion 13, except for the plate thickness changing portion 16 at one axial end, the plate thickness t13 is constant over the entire axial length. The plate thickness t11 of the first flange portion 11 is set to be smaller (thinner) than the plate thickness t13 of the outer ring portion 13. In the embodiment, the plate thickness t11 of the first flange portion 11 is set to be 45% or more and less than 70% of the plate thickness t13 of the outer ring portion 13. By setting the plate thickness in this way, the inhibitory effect of the generation of seizure is further improved. That is, by setting the plate thickness t11 of the first flange portion 11 to be thinner than the plate thickness t13 of the outer ring portion 13, the rigidity of the flange portion is reduced, and smooth press-fitting is achieved. In addition, since the first flange portion 11 is a flange portion on the post-bending process side, such a plate thickness setting also contributes to the facilitation of the post-bending process.

[0037] Here, if the ratio of the plate thickness t11 of the first flange portion 11 to the plate thickness t13 of the outer ring portion 13 is less than 45%, the shape of the first flange portion 11 may become unstable during the stamping process of the cup-shaped outer ring 10. In addition, since the plate thickness t11 of the first flange portion 11 is too thin, there is also a possibility that the first flange portion 11 is deformed when the cup-shaped outer ring 10 is press-fitted into the housing H. On the contrary, if this ratio becomes 70% or more, the rigidity of the cup-shaped outer ring 10 becomes high, and there is a tendency for seizure to easily occur. In these respects, it is also preferable that the ratio of the plate thickness t11 of the first flange portion 11 to the plate thickness t13 of the outer ring portion 13 is set to 45% or more and less than 70%.

[0038] In addition, as Figure 2AAs shown, the inner diameter side end 11a of the first flange portion 11 is the most inwardly projecting portion among the various portions of the first flange portion 11. In the embodiment, the first flange portion 11 includes a first portion 11c connected to the inner diameter side of the bent portion 14 and a second portion 11d connected to the inner diameter side of the first portion 11c. The first portion 11c extends linearly in the radial direction of the roller bearing 1 from the inner diameter side end of the bent portion 14. The side surface 11b of the first portion 11c is the most outwardly convex portion of the shell-shaped outer ring 10 toward one axial end side. The second portion 11d extends in a direction slightly inclined toward the other axial end side as it goes from the inner diameter side end of the first portion 11c toward the inner diameter side. The inner diameter side end 11a of the first flange portion 11 corresponds to the front edge of the one axial end side of the inclined second portion 11d.

[0039] The bent portion 14 on the one axial end side is located at the outer diameter side end of the first flange portion 11 and combines the first flange portion 11 with the outer ring portion 13. The outer surface 18 and the inner surface 19 of the bent portion 14 are concentric circles formed by arcs with a single radius in any longitudinal section including the axis O of the roller bearing 1. The outer surface 18 of the bent portion 14 forms an arc-shaped ridge portion that bulges outward on the entire circumference of the shell-shaped outer ring 10, so that the press-fitting of the shell-shaped outer ring 10 into the housing H is smoother.

[0040] Here, in order to prevent the occurrence of seizure, it is preferable that the hardness of at least the first flange portion 11 of the shell-shaped outer ring 10 is 600 HV (Vickers hardness) or less. This is because if the hardness of the first flange portion 11 is too high (too hard), seizure is likely to occur. In addition, HV (Vickers hardness) determines the hardness of a test body based on the area of the indentation formed when a rigid body (indenter) made of diamond is pressed into the test body. Its measurement method is based on Japanese Industrial Standard JIS-Z 2244:2009. In the embodiment, at least the hardness of the first flange portion 11 is 600 HV or less. However, depending on the material and usage, the entire shell-shaped outer ring 10 may also be 600 HV or less.

[0041] In addition, the outer ring portion 13 has a plate thickness changing portion 16 at the end portion on its one axial end side. The plate thickness of the plate thickness changing portion 16 gradually decreases from the plate thickness t13 of the outer ring portion 13 to the plate thickness t11 of the first flange portion 11. In any longitudinal section including the axis of the shell-shaped outer ring 10, the inner surface 16a of the plate thickness changing portion 16 includes an inclined surface that faces the outer diameter side as it approaches the first flange portion 11. This inclined surface 16a forms an angle α with respect to the axis of the shell-shaped outer ring 10 (see Figure 2B)。The angle α is preferably 25° or more and less than 35°. By providing a plate thickness changing portion 16 at the end portion on the axial one end side of the outer ring portion 13, the post-bending process of the first flange portion 11 becomes easy. Here, assuming that the angle α is less than 25 degrees, there is a possibility that the shape becomes unstable during the bending process of the first flange portion 11. On the contrary, when the angle α is 35 degrees or more, the rigidity near the plate thickness changing portion 16 is low, and thus there is a possibility that the components are deformed when the shell-shaped outer ring 10 is pressed into the housing H. In these respects, it is also preferable that the angle α is 25° or more and less than 35°.

[0042] In the embodiment, as Figure 2B shown, the inner surface 16a of the plate thickness changing portion 16 makes the connecting portion 16b to the outer ring portion 13 and the connecting portion 16c to the inner surface 19 of the bending portion 14 arc-shaped respectively to make it smooth, but the form of the connecting portions 16b and 16c can be changed appropriately. For example, the radii rb and rc of the arcs of the respective connecting portions 16b and 16c can be made smaller than the state Figure 2B shown, and conversely, the radii rb and rc of the arcs of the respective connecting portions 16b and 16c can be made larger than the state Figure 2B shown. In addition, the connecting portions 16b and 16c can be a combination of a plurality of arcs with different radii. In addition, as Figure 2B shown, a linear inclined surface (conical surface) formed with a single slope can be interposed in the middle of the inner surface 16a of the plate thickness changing portion 16, or the inner surface 16a of the plate thickness changing portion 16 can be one without interposing such a linear inclined surface. When the linear inclined surface is not interposed in the inner surface 16a of the plate thickness changing portion 16, the maximum angle (acute angle) of each part of the inner surface 16a of the plate thickness changing portion 16 with respect to the axial direction may be the above-mentioned angle α.

[0043] In addition, in the embodiment, the outer surface 18 and the inner surface 19 of the bending portion 14 are concentric circles composed of arcs formed with a single radius, but the form of the bending portion 14 is not limited to this embodiment. In addition, for example, a conical surface that smoothly connects from the outer surface 17 side of the outer ring portion 13 to the outer surface 18 side of the bending portion 14 can be provided at the axial one end of the outer surface 17 of the outer ring portion 13. In this case, the angle of the conical surface with respect to the axial direction of the roller bearing 1 in any longitudinal section including the axis O of the roller bearing 1 can be set, for example, to gradually face the inner diameter side at an angle of 0.5 degrees or more and less than 5 degrees as it faces the first flange portion 11 side.

[0044] Similarly, the second flange portion 12 stands up from the other axial end of the cylindrical outer ring portion 13 toward the inner diameter side. The structure of the bent portion 14 is the same as that of the first flange portion 11. In addition, the side surface 12b of the second flange portion 12 extends linearly along the radial direction of the roller bearing 1 from the inner diameter side end of the bent portion 14. The distance between the side surface 12b of the second flange portion 12 and the side surface 11b of the first flange portion 11 corresponds to the axial width A of the housing-shaped outer ring 10. In addition, the second flange portion 12 side is the rear end side during press-fitting, and the plate thickness t12 of the second flange portion 12 is not likely to cause galling during press-fitting. Further, since the outer ring portion 13 forming the raceway surface 15 is subjected to deep drawing processing, the plate thickness t12 of the second flange portion 12 can also be set to be greater than the plate thickness t13 of the outer ring portion 13.

[0045] In addition, in the present embodiment, regarding Figure 1 the outer diameter R of the housing-shaped outer ring 10 shown, by adopting the following structure, the effect of preventing the occurrence of galling during press-fitting into the housing H is further improved. That is, as Figure 3 shown, within the axial width A of the housing-shaped outer ring 10, between the outer diameter Ra at the other axial end 13a of the opposed range B of the outer ring portion 13 with respect to the rolling surface 31 of the roller 30, the outer diameter Rb at the axial center 13b of the opposed range B, and the outer diameter Rc at the one axial end 13c of the opposed range B, preferably Rb>Ra≥Rc or Rb>Rc>Ra holds. In addition, preferably, the difference between Rb and Ra and the difference between Rb and Rc are each about 10 to 30 μm. In Figure 3 , the housing-shaped outer ring 10 in the state of being press-fitted into the housing H is shown, but the numerical values of the outer diameter Ra, the outer diameter Rb, and the outer diameter Rc represented by the above various expressions of Rb>Ra≥Rc and Rb>Rc>Ra are respectively the numerical values of the outer diameters of the respective positions of the housing-shaped outer ring 10 before press-fitting.

[0046] Figure 4 Schematically shows the housing-shaped outer ring 10 in the state of being press-fitted into the inner diameter of the housing H, and the pressing force in the inner diameter direction centered on the axis O indicated by the reference numeral X and the pressing force in the outer diameter direction indicated by the reference numeral Y are each suppressed to be smaller than before.

[0047] It should be considered that the embodiments disclosed herein are illustrative in all respects and not restrictive. The scope of the present invention is not the above description, but is shown by the scope of claims of this application, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims of this application.

Claims

1. A roller bearing, characterized in that, Comprising: A shell-shaped outer ring (10), which is annular; a retainer (20) fitted into the shell-shaped outer ring (10); and rollers (30) retained by the retainer (20), The shell-shaped outer ring (10) comprises: an outer ring portion (13) forming a raceway surface (15) opposed to the rolling surface (31) of the roller (30); a first flange portion (11) protruding toward the inner diameter side from one axial end of the outer ring portion (13); a second flange portion (12) protruding toward the inner diameter side from the other axial end of the outer ring portion (13); and a bent portion (14) provided between the outer ring portion (13) and the first flange portion (11) and between the outer ring portion (13) and the second flange portion (12), The inner diameter (r11) of the inner diameter side end (11a) of the first flange portion (11) is set to be 80% or more and less than 95% of the outer diameter (r20) of the maximum diameter portion of the retainer (20).

2. The roller bearing according to claim 1, wherein The shell-shaped outer ring (10) is press-fitted into the inner diameter of the housing, and the first flange portion (11) is set to be the front end side when press-fitted into the inner diameter of the housing.

3. The roller bearing according to claim 1 or 2, wherein The plate thickness (t11) of the first flange portion (11) is set to be 45% or more and less than 70% of the plate thickness (t13) of the outer ring portion (13).

4. The roller bearing according to any one of claims 1 to 3, wherein At an end on the axial one end side of the outer ring portion (13), there is a plate thickness changing portion (16), the plate thickness of the plate thickness changing portion (16) gradually decreases from the plate thickness (t13) of the outer ring portion (13) to the plate thickness (t11) of the first flange portion (11), and the inner surface (16a) of the plate thickness changing portion (16) is an inclined surface that faces the outer diameter side at an angle of 25° or more and less than 35° with respect to the axial direction as it approaches the first flange portion (11).

5. The roller bearing according to any one of claims 1 to 4, wherein The hardness of at least the first flange portion (11) of the shell-shaped outer ring (10) is 600 HV or less.

6. The roller bearing according to any one of claims 1 to 5, wherein Between the outer diameter Ra at the axial other end (13a) of the opposed range of the outer ring portion (13) with the rolling surface (31), the outer diameter Rb at the axial center (13b) of the opposed range of the outer ring portion (13) with the rolling surface (31), and the outer diameter Rc at the axial one end (13c) of the opposed range of the outer ring portion (13) with the rolling surface (31), Rb>Ra≥Rc or Rb>Rc>Ra holds.

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