Rolling bearings

Abstract

The rolling bearing 10 includes an inner ring 11 having an inner ring raceway 16, an outer ring 12 having an outer ring raceway 17, a plurality of balls 13 that roll and contact the inner ring raceway 16 and the outer ring raceway 17, a cage 14 that holds the plurality of balls 13, and a pair of sealing devices 15 located on both axial sides of the inner ring 11 and the outer ring 12. Each of the pair of sealing devices 15 is attached to one of the raceways of the inner ring 11 and the outer ring 12, and is annular and extends toward the other of the raceways of the inner ring 11 and the outer ring 12. Each of the pair of sealing devices 15 is not in contact with the other raceway. Oil is applied to the inner ring raceway 16, the outer ring raceway 17, and the balls 13, and grease G is provided between the pair of sealing devices 15. The grease G is provided in a non-stirring area other than the area through which the balls 13 and the cage 14 pass.

Description

[Technical field]

[0001] The present invention relates to a rolling bearing. [Background technology]

[0002] It is desirable to reduce the rotational resistance of rolling bearings. Patent Document 1 discloses a ball bearing in which a solid lubricant is provided in the internal space of the bearing. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2022-53851 Summary of the Invention [Problem to be solved by the invention]

[0004] For example, in the case of rolling bearings used in bicycle parts (wheels, etc.), it is necessary to reduce the rotational resistance of the rolling bearings in order to reduce fatigue of the bicycle user when riding the bicycle over long distances, or to increase the riding speed in races, etc. Factors that cause the rotational resistance in rolling bearings include the stirring resistance of the grease inside the bearing, the rolling resistance of the balls against the raceway, and the sliding resistance between the raceway and the sealing devices provided on both sides of the bearing.

[0005] Therefore, an object of the present invention is to provide a rolling bearing that makes it possible to reduce the rotational resistance. [Means for solving the problem]

[0006] The rolling bearing according to the embodiment of the present invention comprises: an inner ring having an inner ring raceway; an outer ring having an outer ring raceway; a plurality of rolling elements that roll and contact the inner ring raceway and the outer ring raceway; a cage for holding the plurality of rolling elements; A pair of sealing devices located on both axial sides of the inner ring and the outer ring; Equipped with each of the pair of sealing devices is attached to one of the inner ring and the outer ring and has an annular shape extending toward the other of the inner ring and the outer ring; Each of the pair of sealing devices is in non-contact with the other raceway ring, Oil is applied to the inner ring raceway, the outer ring raceway, and the rolling elements, Grease is provided between the pair of sealing devices, The grease is provided in a non-agitated area other than the areas through which the rolling elements and the cage pass. Effect of the Invention

[0007] According to the rolling bearing of the present invention, it is possible to reduce the rotational resistance. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a cross-sectional view showing an embodiment of a rolling bearing of the present invention. [Diagram 2] FIG. 2 is a schematic diagram showing a state in which the rolling bearing shown in FIG. 1 is used in a bicycle component. [Diagram 3] FIG. 3 is an enlarged cross-sectional view showing a first axial side of the rolling bearing 10. As shown in FIG. [Figure 4] FIG. 4 is a graph showing the rotational resistance of a rolling bearing. [Diagram 5] FIG. 5 shows the experimental results of the wheel speed reduction when a rolling bearing is used in a bicycle wheel. [Figure 6] FIG. 6 is a cross-sectional view of a conventional rolling bearing. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] <Overview of the embodiment of the present invention> Hereinafter, an outline of an embodiment of the present invention will be described. (1) A rolling bearing according to an embodiment of the present invention is an inner ring having an inner ring raceway; an outer ring having an outer ring raceway; a plurality of rolling elements that roll and contact the inner ring raceway and the outer ring raceway; a cage for holding the plurality of rolling elements; A pair of sealing devices located on both axial sides of the inner ring and the outer ring; Equipped with each of the pair of sealing devices is attached to one of the inner ring and the outer ring and has an annular shape extending toward the other of the inner ring and the outer ring; Each of the pair of sealing devices is in non-contact with the other raceway ring, Oil is applied to the inner ring raceway, the outer ring raceway, and the rolling elements, Grease is provided between the pair of sealing devices, The grease is provided in a non-agitated area other than the areas through which the rolling elements and the cage pass.

[0010] With this rolling bearing, the oil reduces the rotational resistance. The base oil of the grease is replenished to the outer ring raceway, the inner ring raceway, and the rolling elements, thereby reducing the rotational resistance over the long term. Since the grease is provided in the non-stirring area, no shear resistance of the grease occurs when the bearing rotates. When the bearing rotates, no sliding resistance occurs between the sealing device and the other raceway. As described above, it is possible to reduce the rotational resistance of the rolling bearing.

[0011] (2) Preferably, the outer ring is a rotating ring, the inner ring is a fixed ring, and the sealing device is attached to the outer ring and does not contact the inner ring. In this case, it is possible to reduce the rotational resistance in the outer ring rotating rolling bearing.

[0012] (3) In the rolling bearing of (1) or (2), preferably, the rolling elements are balls, the outer ring raceway is formed by a groove having an arc-shaped cross section with a radius of curvature that is 57% or more and 61% or less of the diameter of the balls, and the inner ring raceway is formed by a groove having an arc-shaped cross section with a radius of curvature that is 57% or more and 61% or less of the diameter of the balls. With this rolling bearing, the contact ellipse between the balls and the outer ring raceway and the contact ellipse between the balls and the inner ring raceway are relatively small, making it possible to reduce the resistance caused by these contacts.

[0013] (4) In the case of the rolling bearing of (3) above, the radii of curvature of the outer ring raceway and the inner ring raceway are relatively large, so the axial clearance in the rolling bearing tends to be large. As a result, the relative axial displacement between the inner ring and the outer ring may be large. Even in such a case, it is preferable that annular seal grooves are provided on both axial sides of the other raceway, a part of the sealing device is inserted into the seal grooves, and the axial width dimension of the seal groove is set to a value such that the sealing device does not contact the seal groove even when the inner ring and the outer ring are displaced axially relative to each other. In this rolling bearing, a labyrinth gap is provided between the sealing device and the seal groove, improving sealing performance. Even if the axial clearance in the rolling bearing is large, the sealing device does not contact the seal groove, and no sliding resistance is generated between the sealing device and the other raceway ring when the bearing rotates.

[0014] (5) In any one of the rolling bearings of (1) to (4), preferably, the sealing device has a first circumferential wall portion fixed to the one of the raceways, a second circumferential wall portion located on the side of the other raceway, and an annular side wall portion connecting the first circumferential wall portion and the second circumferential wall portion, and a recess is provided between the first circumferential wall portion, the second circumferential wall portion, and the side wall portion, and the grease, which is of a channeling type, is provided in the recess. According to this rolling bearing, the grease is efficiently provided in the non-agitated region.

[0015] (6) In any one of the rolling bearings described in (1) to (5), the volume of the grease is preferably 5% or more and 15% or less of the volume of the space between the pair of sealing devices, excluding the plurality of rolling elements and the cage. According to this rolling bearing, the grease is efficiently provided in the non-agitated region, and the bearing lubricating performance is maintained for a long period of time.

[0016] (7) In the rolling bearing of any one of (1) to (6) above, the rolling elements are preferably made of ceramic, and the cage is preferably made of resin. This rolling bearing reduces the sliding resistance between the rolling elements and the cage, which contributes to reducing the rotational resistance.

[0017] <Details of the embodiment of the present invention> Hereinafter, an embodiment of the present invention will be described. [Overall configuration of rolling bearing] Fig. 1 is a cross-sectional view showing one embodiment of a rolling bearing of the present invention. The rolling bearing 10 shown in Fig. 1 is used, for example, in bicycle parts (wheels, transmissions, bottom brackets, etc.). The rolling bearing 10 is used under rotation conditions such that the DMN value is, for example, 10,000 or less. The rolling bearing 10 is used at room temperature, and the operating temperature environment is, for example, 0 degrees or more and 60 degrees or less.

[0018] The rolling bearing 10 includes an inner ring 11, an outer ring 12, a plurality of rolling elements, a cage 14 that holds the plurality of rolling elements, and a pair of sealing devices 15. In this embodiment, the rolling elements are balls 13, and the rolling bearing 10 is a ball bearing. The sealing devices 15 are located on both axial sides of the inner ring 11 and the outer ring 12.

[0019] The directions of the rolling bearing 10 will be explained. One of the raceways (outer ring 12) of the rolling bearing 10 rotates around a central axis C. The direction parallel to the central axis C is defined as the "axial direction" of the rolling bearing 10. The direction perpendicular to the central axis C is defined as the "radial direction" of the rolling bearing 10. The direction along a circle centered on the central axis C is defined as the "circumferential direction" of the rolling bearing 10.

[0020] Fig. 2 is a schematic diagram showing the rolling bearing 10 shown in Fig. 1 being used in a bicycle component. A bicycle hub 7 rotates about an axle 8. The rotating hub 7 is supported by two rolling bearings 10. The two rolling bearings 10 have the same configuration. In this embodiment, the outer ring 12 is a rotating ring, and the inner ring 11 is a fixed ring. Depending on the application location of the rolling bearing 10, the inner ring 11 may be a rotating ring, and the outer ring 12 may be a fixed ring.

[0021] The hub 7 has a small diameter portion 7a on its inner circumferential side and in the axial center. The outer rings 12 of the two rolling bearings 10 are attached to a mounting surface 7b of the hub 7 with the small diameter portion 7a sandwiched between them. The inner diameter of the mounting surface 7b is larger than the inner diameter of the small diameter portion 7a. For example, an axial force is applied to the inner rings 11 of the two rolling bearings 10 in a direction in which they approach each other by a biasing member 9 such as a wave washer attached to the shaft 8. The axial force is, for example, 100 N or more and 200 N or less. In each of the two rolling bearings 10, the balls 13 contact the inner ring 11 and the outer ring 12 with a contact angle. The two rolling bearings 10 are mounted between the hub 7 and the shaft 8 in a back-to-back arrangement via a part of the hub 7 (small diameter portion 7a). The rolling bearings 10 may be used in a state in which no axial force is applied.

[0022] Each part of the rolling bearing 10 will be described with reference to Figure 1. Figure 1 is a cross-sectional view taken along a plane including a central axis C. The inner ring 11 has an inner ring raceway 16 on its outer periphery. As shown in the cross-sectional view of Figure 1, the inner ring raceway 16 is formed of a groove having a circular arc-shaped cross section. The outer ring 12 has an outer ring raceway 17 on its inner periphery. The outer ring raceway 17 is formed of a groove having a circular arc-shaped cross section. A plurality of balls 13 roll on and come into contact with the inner ring raceway 16 and the outer ring raceway 17.

[0023] Oil is applied to the inner ring raceway 16, the outer ring raceway 17 and the balls 13. The oil is a low viscosity oil, for example, Mobil Velocity Oil Number 3. The oil is applied when assembling the rolling bearing 10. For example, oil is applied to the outer ring raceway 17, and the rolling bearing 10 is rotated so that the oil is also applied to the balls 13 and the inner ring raceway 16. In order to prevent the oil from becoming excessive, an oil splashing process is performed in which the rolling bearing 10 is rotated at a predetermined number of revolutions for a predetermined time with the sealing device 15 not attached to the rolling bearing 10 to remove excess oil.

[0024] The inner ring 11 has shoulders 26 on both axial sides of the inner ring raceway 16. The outer peripheral surface of shoulder 26 is a cylindrical surface centered on central axis C. The outer ring 12 has shoulders 27 on both axial sides of the outer ring raceway 17. The inner peripheral surface of shoulder 27 is a cylindrical surface centered on central axis C. The rolling bearing 10 is a deep groove ball bearing, which is capable of supporting radial loads as well as axial loads in both directions.

[0025] Mounting grooves 29 for the sealing device 15 are provided on both axial sides of the outer ring 12. The right side of Fig. 1 is defined as the "first axial side", and the left side is defined as the "second axial side". Fig. 3 is an enlarged cross-sectional view showing the first axial side of the rolling bearing 10. The mounting grooves 29 are recessed grooves that open to the inner ring 11 side and to the side opposite the balls 13 in the axial direction. The sealing device 15 is mounted in the mounting grooves 29.

[0026] An annular seal groove 28 is provided on both sides of the inner ring 11 in the axial direction. As shown in FIG. 3, the seal groove 28 has a groove bottom surface 28a having a smaller diameter than the outer peripheral surface 26a of the shoulder 26, and a groove side surface 28b located between the groove bottom surface 28a and the outer peripheral surface 26a of the shoulder 26. The seal groove 28 is a concave groove that opens to the outer ring 12 side and to the opposite side to the balls 13 in the axial direction (the first side in the axial direction). A part of the sealing device 15 is inserted into the seal groove 28. The sealing device 15 is attached to an attachment groove 29 of the outer ring 12, and as will be described later, a part of the sealing device 15 is not in contact with the seal groove 28 of the inner ring 11.

[0027] The cage 14 holds a plurality of balls 13. In Fig. 1, the cage 14 of this embodiment has one annular body 21 located on a first axial side of the balls 13, and a plurality of pillars 22 extending from the annular body 21 to a second axial side. The space formed between two circumferentially adjacent pillars 22 becomes a pocket in which the balls 13 are accommodated. The cage 14 is a so-called crown-type cage, but may have other forms.

[0028] The sealing devices 15 are provided on both axial sides of the annular space formed between the inner ring 11 and the outer ring 12. The sealing device 15 located on the first axial side and the sealing device 15 located on the second axial side have the same configuration, but are attached in opposite directions. The sealing device 15 prevents the grease G in the space inside the bearing formed between the inner ring 11 and the outer ring 12 and in which the balls 13 are present from leaking out to the outside. The sealing device 15 also prevents foreign matter from the outside from entering the space inside the bearing. In this embodiment, each of the pair of sealing devices 15 is attached to the outer ring 12 and has an annular shape extending toward the inner ring 11. Note that each of the pair of sealing devices 15 may be attached to one of the raceways of the inner ring 11 and the outer ring 12 and has an annular shape extending toward the other of the raceways of the inner ring 11 and the outer ring 12.

[0029] As shown in Fig. 3, the sealing device 15 is generally annular, and includes a metal ring 31 and an elastic member 32 fixed to the metal ring 31. In this embodiment, the elastic member 32 is made of rubber. The metal ring 31 includes a cylindrical portion 35 that is short in the axial direction, an annular portion 36 that extends from the axial end of the cylindrical portion 35 toward the inner ring 11, and an inclined portion 37 that extends from the radially inner end of the annular portion 36. The inclined portion 37 has an inclined shape that slopes toward the balls 13 as it approaches the inner ring 11.

[0030] The elastic material 32 has a fixed portion 38 that covers the cylindrical portion 35, a lip portion 39 that covers the inclined portion 37, and a membrane portion 40 that covers the annular portion 36. The cylindrical portion 35 and the fixed portion 38 form a first circumferential wall portion 41. The first circumferential wall portion 41 has a short cylindrical shape in the axial direction. The inclined portion 37 and the lip portion 39 form a second circumferential wall portion 42. The annular portion 36 and the membrane portion 40 form an annular side wall portion 43.

[0031] The first peripheral wall portion 41 is fixed by being fitted into the mounting groove 29 of the outer ring 12. The second peripheral wall portion 42 is located on the inner ring 11 side. The second peripheral wall portion 42 is provided extending with an axial component and a radial component. The side wall portion 43 connects the end of the first peripheral wall portion 41 away from the balls 13 and the end of the second peripheral wall portion 42 away from the balls 13. With the above configuration, in the sealing device 15, a recess 44 is provided between the first peripheral wall portion 41, the second peripheral wall portion 42, and the side wall portion 43. The recess 44 is continuous in the circumferential direction. The grease G is applied to this recess 44. The base oil of the grease G is supplied from the first peripheral wall portion 41 to the outer ring raceway 17 through the inner circumferential surface of the shoulder 27. Since the inner circumferential surface of the first circumferential wall portion 41 and the inner circumferential surface of the shoulder 27 are in the same range (at the same position) in the radial direction, the base oil is easily supplied to the outer ring raceway 17.

[0032] As described above, the sealing device 15 does not contact the seal groove 28. To be more specific (see FIG. 3), the sealing device 15 has a lip portion 39. The lip portion 39 is provided along the inclined portion 37 and has a first protrusion 46 that approaches the balls 13 as it approaches the inner ring 11, and a second protrusion 47 that extends from the inclined portion 37 toward the inner ring 11. The first protrusion 46 is located radially outward of the shoulder 26 of the inner ring 11 and is located close to the shoulder 26. Even if the inner ring 11 and the outer ring 12 are displaced relatively in the axial direction, the first protrusion 46 does not contact the inner ring 11, including the shoulder 26.

[0033] The second projection 47 is located at a position where it enters the seal groove 28. A radially inner end face 47a of the second projection 47 faces the groove bottom face 28a, and a side face 47b of the second projection 47 on the ball 13 side faces the groove side face 28b. The second projection 47 is close to the groove bottom face 28a and the groove side face 28b. However, even if the inner ring 11 and the outer ring 12 are displaced relatively in the axial direction, the second projection 47 does not come into contact with the groove bottom face 28a and the groove side face 28b. As described above, each of the pair of sealing devices 15 does not come into contact with the inner ring 11. A labyrinth gap is provided between the lip portion 39 and the seal groove 28, and the sealing performance of the sealing device 15 is improved.

[0034] Grease G is provided in an unstirred region Q between a pair of sealing devices 15, which will be described later. The grease G is of a channeling type. For example, the kinetic viscosity (40 degrees) of the grease G is 25 mm^2 / s or less. The base oil of the grease G is preferably an ester oil, which is a low-viscosity base oil, for example, Multemp SRL, in this embodiment. The thickener of the grease G is preferably lithium soap. The grease G is provided only in the unstirred region Q between the pair of sealing devices 15, which is other than the region through which the balls 13 and the cage 14 pass when the bearing rotates.

[0035] More specifically, grease G is provided in the recess 44 of the sealing device 15. The grease G is provided by adhering to the side wall portion 43 of the sealing device 15. The grease G is not in contact with the balls 13 and the cage 14 (annular body 21). By providing the grease G in the recess 44, the grease G is efficiently provided in the non-stirring region Q.

[0036] Incidentally, when assembling the rolling bearing 10, the grease G may be provided outside the unstirred region Q (i.e., the region through which the balls 13 or the cage 14 pass). The grease G is of a channeling type. Therefore, after the assembly is completed, by rotating the rolling bearing 10 for a predetermined time, the grease G will eventually be present only in the unstirred region Q. By rotating the rolling bearing 10 for a predetermined time, the grease G may eventually be in a state where it is not in contact with the cage 14 (annular body 21). The sealing device 15, in which the grease G has been applied in advance to the recess 44, may be assembled to the rolling bearing 10 (outer ring 12).

[0037] The volume of the grease G provided in the rolling bearing 10 (the total volume of the first and second axial sides) is preferably 5% or more and 15% or less of the volume of the space K between the pair of sealing devices 15, excluding the plurality of balls 13 and the cage 14. This allows the grease G to be efficiently provided in the non-stirring region Q, and also maintains the bearing lubrication performance for a long period of time. The space K is the space between the pair of sealing devices 15, and is the space between the side surface 47b of the second protrusion 47 of the sealing device 15 on the first axial side and the side surface 47b of the second protrusion 47 of the sealing device 15 on the second axial side.

[0038] The grease G is provided separately in a recess 44 of the sealing device 15 on the first side in the axial direction and a recess 44 of the sealing device 15 on the second side in the axial direction. The amount of grease G is smaller on the side of the retainer 14 where the annular body 21 exists (right side in FIG. 1) than on the opposite side (left side in FIG. 1). This makes it difficult for the grease G to come into contact with the retainer 14 (annular body 21). The non-stirring region Q is filled with the grease G, so that the annular body 21 and the grease G do not come into contact with each other. In particular, the recess 44 is filled with the grease G, so that the annular body 21 and the grease G do not come into contact with each other. The amount of grease G is larger on the side of the retainer 14 where the annular body 21 does not exist (left side in FIG. 1) than on the opposite side (right side in FIG. 1). This makes it possible to apply a larger amount of grease G overall.

[0039] The inner ring 11 and the outer ring 12 are made of steel. In this embodiment, the inner ring 11 and the outer ring 12 are made of stainless steel (SUS440C) to prevent rust. The balls 13 may be made of steel, but in this embodiment, they are made of ceramic (silicon nitride). The cage 14 is made of resin. The cage 14 is made by injection molding, and is therefore made of thermoplastic resin. This reduces the sliding resistance between the balls 13 and the cage 14, contributing to reducing rotational resistance. The sealing device 15 is composed of a metal ring 31 made of metal (stainless steel) and an elastic material 32 made of rubber.

[0040] As described above, the outer ring raceway 17 and the inner ring raceway 16 are formed of concave grooves having an arc-shaped cross section. The shapes of the concave grooves will be further explained. The outer ring raceway 17 is formed of a concave groove having an arc-shaped cross section with a radius of curvature of 57% or more and 61% or less of the diameter of the balls 13. The inner ring raceway 16 is formed of a concave groove having an arc-shaped cross section with a radius of curvature of 57% or more and 61% or less of the diameter of the balls 13.

[0041] With this configuration, the contact ellipse between balls 13 and outer ring raceway 17 and the contact ellipse between balls 13 and inner ring raceway 16 become relatively small. As a result, it is possible to reduce the resistance caused by these contacts. The radii of curvature of outer ring raceway 17 and inner ring raceway 16 are relatively large, being 57% or more and 61% or less of the diameter of ball 13. This tends to increase the axial clearance in rolling bearing 10 of this embodiment. As a result, the relative axial displacement between inner ring 11 and outer ring 12 may increase.

[0042] Even if the inner ring 11 and the outer ring 12 are displaced relatively in the axial direction, the sealing device 15 does not contact the seal groove 28. A second protrusion 47, which is a part of the sealing device 15, is inserted into the seal groove 28. Therefore, the axial width dimension of the seal groove 28 is set to a value such that the sealing device 15 (second protrusion 47) does not contact the seal groove 28 even if the inner ring 11 and the outer ring 12 are displaced relatively in the axial direction. As described above, even if the axial clearance in the rolling bearing 10 is large, the sealing device 15 does not contact the seal groove 28, and no sliding resistance is generated between the sealing device 15 and the inner ring 11 when the bearing rotates.

[0043] As described above, the rolling bearing 10 of this embodiment includes a pair of sealing devices 15 located on both axial sides of the inner ring 11 and the outer ring 12. Each of the pair of sealing devices 15 is attached to the outer ring 12 and has an annular shape extending toward the inner ring 11. Each of the pair of sealing devices 15 does not contact the inner ring 11. Oil is applied to the inner ring raceway 16, the outer ring raceway 17, and the balls 13 as a lubricant. Grease G is provided between the pair of sealing devices 15. The grease G is provided in an unstirred region Q other than the region through which the balls 13 and the cage 14 pass.

[0044] According to the rolling bearing 10 of this embodiment, the oil reduces the rotational resistance. The base oil of the grease G is replenished to the outer ring raceway 17, the inner ring raceway 16, and the balls 13, thereby reducing the rotational resistance over a long period of time. Since the grease G is provided in the non-stirring region Q, no shear resistance of the grease G occurs when the bearing rotates. When the bearing rotates, no sliding resistance occurs between the sealing device 15 and the inner ring 11. As described above, it is possible to reduce the rotational resistance of the rolling bearing 10.

[0045] In this embodiment, the sealing device 15 is attached to the outer ring 12 and does not contact the inner ring 11, making it possible to reduce the rotational resistance in the outer ring rotating rolling bearing 10. The rolling bearing 10 of this embodiment is suitable for use as a bicycle wheel bearing.

[0046] 6 is a cross-sectional view of a conventional rolling bearing 90. In the conventional rolling bearing 90, a pair of sealing devices 95 contacts an inner ring 91. Grease G is also provided in the areas through which balls 93 and cage 94 pass. An inner ring raceway 96 and an outer ring raceway 97 are formed of a concave groove having a cross-sectional arc shape that is less than 57% of the diameter of balls 93. The cage 94 is made of resin, while the balls 93 are made of bearing steel.

[0047] Fig. 4 is a graph showing the rotational resistance (torque) of a conventional rolling bearing and the rolling bearing 10 of this embodiment. As shown in Fig. 4, the rotational resistance of the rolling bearing 10 of this embodiment shown in Fig. 1 is 1 / 10 or less of the rotational resistance of the conventional rolling bearing 90 shown in Fig. 6.

[0048] FIG. 5 is a diagram showing the experimental results of wheel speed reduction when the rolling bearing 10 of this embodiment shown in FIG. 1 and the conventional rolling bearing 90 shown in FIG. 6 are used on bicycle wheels. The vertical axis represents wheel speed, and the horizontal axis represents time. FIG. 5 shows the reduction in wheel speed over time after the wheel is rotated at a predetermined speed. In FIG. 5, (a) shows the case of the rolling bearing 10 of this embodiment shown in FIG. 1, and (b) shows the case of the conventional rolling bearing 90.

[0049] As shown in Fig. 5, in the case of the rolling bearing 10 of this embodiment shown in Fig. 1, the speed is less likely to decrease compared to the conventional rolling bearing 90 shown in Fig. 6. In other words, it is clear that the rotational resistance is smaller. As described above, by using the rolling bearing 10 of this embodiment in bicycle parts (wheels, etc.), it is possible to reduce fatigue of the bicycle user when riding long distances, or to increase the riding speed during competitions, etc.

[0050] [Other matters] In the above embodiment, the sealing device 15 is attached to the outer ring 12 and does not contact the inner ring 11. In the present invention, the sealing device 15 may be attached to the inner ring 11 and does not contact the outer ring 12. That is, each of the pair of sealing devices 15 is attached to one of the raceways of the inner ring 11 and the outer ring 12, has an annular shape extending toward the other raceway of the inner ring 11 and the outer ring 12, and does not contact the other raceway. Also, although the case where the outer ring 12 is the rotating ring has been described, the inner ring 11 may be the rotating ring.

[0051] Although the rolling bearing 10 of this embodiment has been described as being used in a bicycle, it may be used in other applications, for example, it may be applied to vehicles that are propelled by human power.

[0052] The above-described embodiment is illustrative in all respects and is not restrictive. The scope of the present invention is defined by the claims rather than the above-described embodiment, and includes all modifications within the scope equivalent to the configurations described in the claims. [Explanation of symbols]

[0053] 10. Rolling bearings 11. Inner Circle 12 Outer ring 13 Ball (rolling element) 14 Cage 15 Sealing device 16 Inner raceway 17 Outer raceway Grease 28 Seal groove 41 First peripheral wall part 42 Second peripheral wall part 43 Side wall 44 Recess

Claims

1. an inner ring having an inner ring raceway; an outer ring having an outer ring raceway; a plurality of rolling elements that roll and contact the inner ring raceway and the outer ring raceway; a cage for holding the plurality of rolling elements; A pair of sealing devices located on both axial sides of the inner ring and the outer ring; Equipped with each of the pair of sealing devices is attached to one of the inner ring and the outer ring and has an annular shape extending toward the other of the inner ring and the outer ring; Each of the pair of sealing devices is in non-contact with the other raceway ring, Oil is applied to the inner ring raceway, the outer ring raceway, and the rolling elements, Grease is provided between the pair of sealing devices, The grease is provided in a non-stirring area other than an area through which the rolling elements and the cage pass. Rolling bearing.

2. The outer ring is a rotating ring and the inner ring is a fixed ring, The sealing device is attached to the outer ring and does not contact the inner ring.

2. The rolling bearing according to claim 1.

3. The rolling elements are balls, The outer ring raceway is formed by a groove having a cross-sectional arc shape with a radius of curvature of 57% or more and 61% or less of a diameter of the ball, The inner ring raceway is formed of a groove having a cross-sectional arc shape with a curvature radius of 57% or more and 61% or less of the diameter of the ball.

3. The rolling bearing according to claim 1 or 2.

4. The other raceway ring is provided with annular seal grooves on both sides in the axial direction, A part of the sealing device is inserted into the seal groove, 4. The rolling bearing according to claim 3, wherein an axial width dimension of the seal groove is set to a value such that the sealing device does not come into contact with the seal groove even when the inner ring and the outer ring are displaced relative to each other in the axial direction.

5. The sealing device is a first peripheral wall portion fixed to the one of the races; a second circumferential wall portion located on the other raceway side; a side wall portion having an annular shape connecting the first peripheral wall portion and the second peripheral wall portion; a recess is provided between the first peripheral wall portion, the second peripheral wall portion, and the side wall portion, 3. The rolling bearing according to claim 1, wherein the grease provided in the recess is of a channeling type.

6. 3. The rolling bearing according to claim 1, wherein a volume of the grease is 5% or more and 15% or less of a volume of the space between the pair of sealing devices, excluding the plurality of rolling elements and the cage.

7. 3. The rolling bearing according to claim 1, wherein the rolling elements are made of ceramic, and the cage is made of resin.

Images