Rolling bearing

Abstract

To provide a rolling bearing which can prevent generation of a high-speed whirl phenomenon at a low cost.SOLUTION: In a rolling bearing 1 on which a circumferential clearance is formed between a pocket formation face 7 of a holder 5 in a neutral state and a ball 4, a contact point of the ball 4 against the pocket formation face 7 when the ball 4 is relatively moved in a circumferential direction with respect to the holder 5 in the neutral state is arranged at a position where an angle θ formed by a straight line L1 connecting the contact point and a center of the ball 4 with respect to a plane OP which is orthogonal to an axial direction through the center of the ball 4 is 60° or more and less than 90°.SELECTED DRAWING: Figure 4

Description

[Technical Field]

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

[0002] 8(a) and 8(b) show schematic cross-sectional views of a rolling bearing 100. This rolling bearing 100 comprises a pair of raceways (inner ring 101 and outer ring 102) that are arranged radially opposite each other and rotate relative to each other about a central axis via a plurality of rolling elements (balls) 103, and an annular cage 104 that holds the plurality of rolling elements 103 at intervals in the circumferential direction. The cage 104 is assembled between the inner ring 101 and the outer ring 102 so that, in an unloaded state in which gravity, rotational force, etc. are not acting on the rolling bearing 100, radial gaps 111 and 112 are formed between the cage 104 and the outer peripheral surface 101a of the inner ring 101 and the inner peripheral surface 102a of the outer ring 102, respectively, and a circumferential gap 113 is formed between the cage 104 and the rolling elements 103 housed in the pockets 105. Pocket 105 is a space that accommodates rolling elements 103, and in the illustrated example is a circular hole with a uniform cross-sectional shape along the radial direction. Pocket forming surface 105a is a surface that constitutes the space (pocket 105) provided to accommodate rolling elements 103, and is the surface that comes into contact with and slides against rolling elements 103. The above-mentioned radial clearances 111, 112 are also called "guide clearances," and the above-mentioned circumferential clearance 113 is also called "pocket clearance." Due to the presence of the various clearances described above, cage 104, which is incorporated between the inner and outer rings, is able to move radially and circumferentially when rolling bearing 100 is in operation.

[0003] During operation of the rolling bearing 100, the cage 104 may experience an abnormally high-speed whirl (a whirl several times or more the cage rotation frequency), also known as the high-speed whirl phenomenon. The high-speed whirl phenomenon may cause problems such as abnormal noise, vibration, increased torque, torque fluctuation, and heat generation. The high-speed whirl phenomenon is said to be caused by, for example, frictional forces generated by radial contact between the raceway ring and the cage 104, or frictional forces generated by circumferential contact between the cage 104 (pocket forming surfaces 105a) and the rolling elements 103. The mechanism by which the high-speed whirl phenomenon occurs due to contact between the cage 104 and the rolling elements 103 will be briefly explained below with reference to FIGS. 8(a) and 8(b).

[0004] First, as shown in FIG. 8( a), when the rolling bearing 100 is operated, if the cage 104 is displaced in the 0 o'clock (12 o'clock) direction relative to the axis O, the rolling elements 103 arranged at the 3 o'clock and 9 o'clock positions come into contact with the pocket forming surface 105a of the cage 104 at the 6 o'clock position. If the inner ring 101 is rotating clockwise at this time, a frictional force F is generated between the rolling elements 103 and the cage 104, displacing the cage 104 in the 3 o'clock direction. When the cage 104 is displaced by this frictional force F, the rolling elements 103 arranged at the 0 o'clock and 6 o'clock positions come into contact with the pocket forming surface 105a of the cage 104 at the 9 o'clock position, as shown in FIG. 8( b). Accordingly, a frictional force F is generated, displacing the cage 105 in the 6 o'clock direction. Thereafter, the above-described contact and friction between (the pocket forming surface 105 a of) the cage 104 and the rolling elements 103 is repeated, causing the cage 104 to whirl at high speed in the same direction as the rotation direction of the inner ring 101 .

[0005] In order to prevent the occurrence of abnormal noise, vibration, etc. resulting from the above-mentioned high-speed whirling phenomenon of the cage, for example, in the rolling bearing described in Patent Document 1 below, a predetermined amount of imbalance is intentionally imparted to the cage so that the cage is constantly eccentric with respect to the raceway, i.e., the cage is rotated with part of it constantly in contact with the raceway. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-196513 Summary of the Invention [Problem to be solved by the invention]

[0007] If the technical means described in Patent Document 1 is adopted, the cage must be formed into a point-asymmetric shape, which requires a lot of work to machine the cage with high precision. Furthermore, to ensure the durable life required of a rolling bearing, it is necessary to suppress wear at the area where the cage and raceway are in constant contact, which requires measures such as finishing the two opposing surfaces of the raceway and cage that come into contact with each other with extremely high precision by precision polishing or the like. Therefore, adopting the technical means described in Patent Document 1 poses the problem of high costs.

[0008] In view of the above circumstances, an object of the present invention is to provide a low-cost rolling bearing that can prevent, as much as possible, the occurrence of the high-speed whirl phenomenon caused by frictional forces generated by contact between the cage and the rolling elements, and further the occurrence of abnormal noise and vibrations that may result from this. [Means for solving the problem]

[0009] As described above, one of the causes of the high-speed whirl phenomenon of the cage is the frictional force generated by contact between the rolling elements and (the pocket forming surface of) the cage, which move relative to one another during bearing operation. Therefore, the inventors believed that if the frictional force could be reduced, the occurrence of the high-speed whirl phenomenon could be suppressed or prevented. As a result of extensive research, the inventors discovered that if the rolling elements are made to contact a predetermined area of ​​the pocket forming surface of the cage during bearing operation, the rotational (spinning) speed of the rolling elements at the contact points between the cage and the rolling elements can be reduced, thereby reducing frictional energy and preventing the occurrence of the high-speed whirl phenomenon as much as possible. The present invention was made based on this finding.

[0010] That is, the present invention, which has been devised to achieve the above object, is a rolling bearing comprising a pair of raceways arranged radially opposite to each other and rotating relative to each other via a plurality of rolling elements, and an annular cage in which a plurality of pockets, each accommodating the rolling elements individually, are formed at intervals in the circumferential direction, and in which a circumferential clearance is formed between the rolling elements and the pocket forming surface of the cage in a neutral state, The contact point of the rolling element with the pocket forming surface when the rolling element moves circumferentially relative to the cage in a neutral state is positioned so that the angle θ formed by the line connecting the contact point and the center of the rolling element with a plane that passes through the center of the rolling element and is perpendicular to the axial direction is 60° or more and less than 90°. In the present invention, the term "neutral state" refers to a state in which the center of the pocket and the center of the rolling element coincide with each other, and the cage and the rolling element are not in contact with each other.

[0011] With the rolling bearing according to the present invention having the above-described configuration, the rotational (spinning) speed of the rolling elements when they come into contact with the pocket-forming surfaces of the cage as the cage and the rolling elements move relative to each other in the circumferential direction during bearing operation can be suppressed, thereby reducing the frictional energy generated by contact between the two, thereby making it possible to prevent as much as possible the occurrence of the high-speed whirl phenomenon of the cage caused by this frictional energy.

[0012] The gist of the present invention is to limit the contact positions (contact points) of the rolling elements with the pocket-forming surface of the cage to a predetermined range on the pocket-forming surface, which can be achieved, for example, by devising a special pocket shape. In this case, the pocket formation process does not become particularly complicated. Furthermore, unlike the rolling bearing of Patent Document 1, the rolling bearing of the present invention does not intentionally make the cage eccentric (in contact) with the raceway ring, and therefore does not require time-consuming and costly processing such as precision polishing of the cage or raceway ring. Therefore, the rolling bearing of the present invention can be realized at significantly lower cost than the rolling bearing of Patent Document 1.

[0013] The rolling bearing according to the present invention can be realized, for example, by configuring each pocket as an elliptical hole whose major axis is arranged along the circumferential direction and whose minor axis is arranged along the axial direction. [Effects of the Invention]

[0014] As described above, according to the present invention, it is possible to realize at low cost a rolling bearing that can prevent as much as possible the occurrence of the high-speed whirl phenomenon caused by frictional energy generated by contact between the cage and the rolling elements, as well as the abnormal noise and vibrations that can result from this. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a partial schematic plan view of a rolling bearing according to an embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view taken along the line A1-A1 in FIG. [Figure 3] FIG. 2 is a cross-sectional view taken along the line A2-A2 in FIG. [Figure 4] FIG. 10 is a schematic diagram showing a state in which a ball is in contact with a pocket forming surface of a cage. [Figure 5] 10A and 10B are diagrams illustrating modified examples of pockets of the cage. [Figure 6] Figure (a) is a schematic longitudinal cross-sectional view of a rolling bearing with the rotation axis of the ball added, and Figure (b) is a conceptual diagram in which the balls of the rolling bearing (halved balls) are arranged on a coordinate system with the origin at the center of the balls. [Figure 7] Figure (a) is a line graph showing the relationship between the angle β and the speed ratio when the tilt of the ball's rotation axis relative to the axial direction is set to α = 15°, Figure (b) is a line graph showing the relationship between the angle β and the speed ratio when the tilt is set to α = 20°, and Figure (c) is a line graph showing the relationship between the angle β and the speed ratio when the tilt is set to α = 30°. [Figure 8] FIG. 1(a) is a schematic cross-sectional view of a general rolling bearing, and FIG. 1(b) is a cross-sectional view showing a state in which the cage of the rolling bearing shown in FIG. 1(a) has been displaced in the radial direction. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Unless otherwise specified, the terms "axial direction," "radial direction," and "circumferential direction" used below to indicate directionality refer to a direction parallel to the axis O of the rolling bearing 1 shown in Figure 1, a radial direction of a circle centered on the axis O, and a circumferential direction of a circle centered on the axis O, respectively.

[0017] Fig. 1 is a partial schematic plan view of a rolling bearing 1 according to an embodiment of the present invention, and more specifically, a partial schematic plan view of the rolling bearing 1 in an unloaded state in which gravity, rotational force, and the like are not acting. Fig. 2 is a cross-sectional view taken along line A1-A1 in Fig. 1, and Fig. 3 is a cross-sectional view taken along line A2-A2 in Fig. 1. The rolling bearing 1 shown in Fig. 1 and other figures is a ball bearing comprising a pair of raceways (inner ring 2 and outer ring 3) made of a highly rigid metallic material such as bearing steel (high-carbon chromium bearing steel), a plurality of rolling elements (balls) 4 rollably interposed between the inner ring 2 and the outer ring 3, and an annular cage 5 that holds the plurality of balls 4 at intervals in the circumferential direction. More specifically, it is an angular contact ball bearing in which the balls 4 contact an arc-shaped inner raceway surface 2b formed on the outer peripheral surface 2a of the inner ring 2 and an arc-shaped outer raceway surface 3b formed on the inner peripheral surface 3a of the outer ring 3 at a contact angle α.

[0018] This rolling bearing 1 is used with a lubricant such as grease or lubricating oil placed in the annular space between the inner ring 2 and outer ring 3 to prevent heat generation and abnormal noise caused by contact and sliding between the component parts.

[0019] The cage 5 has a plurality of pockets 6 formed at equal intervals in the circumferential direction, each accommodating one ball 4. As shown in Figures 2 and 3, each pocket 6 is made up of a hole with a uniform cross-sectional shape along the radial direction, and in this case, is made up of an elliptical hole with its major axis aligned along the circumferential direction and its minor axis aligned along the axial direction.

[0020] A resin cage made of a resin material such as PA66 resin or phenolic resin is used as the cage 5. However, the present invention can also be applied to cases where a known cage other than a resin cage is used as the cage 5, such as a so-called machined cage obtained by cutting a metal material into a predetermined shape, or a pressed cage obtained by joining a pair of cage materials that have been press-formed (punched) into a predetermined annular shape.

[0021] 2 and 3 , in an unloaded state in which gravity, rotational force, and the like are not acting on the rolling bearing 1, the cage 5 is in a neutral state (a state in which it is not in contact with the balls 4, or the inner ring 2 or the outer ring 3) in which it forms radial clearances between itself and the inner ring 2 and the outer ring 3, and forms circumferential clearances between itself and the balls 4 accommodated in the pockets 6. Therefore, when the cage 5 is in the neutral state, a first radial clearance Ga1 is formed between the outer peripheral surface 2a of the inner ring 2 and the inner peripheral surface 5a of the cage 5, a second radial clearance Ga2 is formed between the inner peripheral surface 3a of the outer ring 3 and the outer peripheral surface 5b of the cage 5, and a circumferential clearance Gb, also referred to as a "pocket clearance," is formed between the balls 4 and the pocket-forming surface 7 of the cage 5. By setting these various clearances, the cage 5 can move radially and circumferentially when the rolling bearing 1 is in operation, ensuring good operability of the rolling bearing 1. In the illustrated rolling bearing 1, the second radial clearance Ga2 is smaller than the first radial clearance Ga1.

[0022] The characteristic configuration of the rolling bearing 1 of this embodiment having the above configuration will be described below.

[0023] In this rolling bearing 1, when the balls 4 move circumferentially relative to the cage 5 (see FIGS. 2 and 3) in a neutral state, the contact points of the balls 4 with the pocket forming surfaces 7 of the cage 5 are arranged at positions such that the angle θ that a line L1 connecting this contact point and the center of the balls 4 makes with a plane OP that passes through the center of the balls 4 and is perpendicular to the axial direction is equal to or greater than 60° and less than 90° (60°≦θ<90°). This configuration can be obtained, for example, by configuring the pockets 6 as elliptical holes whose major axis is arranged along the circumferential direction and whose minor axis is arranged along the axial direction, as shown in FIGS. 3 and 4.

[0024] When the rolling bearing 1 having the above configuration is operated and the balls 4 move circumferentially relative to the cage 5 (see FIG. 3) which is in a neutral state, the balls 4 come into contact with the pocket forming surface 7 of the cage 5 at two points, as shown in FIG. 4. If the coordinates of this contact point are (m, n), the major axis radius of the elliptical pocket 6 is a, the minor axis radius of the pocket 6 is b, and the radius of the ball 4 is r, the circumferential displacement c of the ball 4 and the coordinates m and n of the contact point can be calculated using the following equations (3) to (5), which are derived based on the "equation of the tangent to the ellipse at the contact point (m, n)" expressed by the following equation (1) and the "equation of the tangent to the circle at the contact point (m, n)" expressed by the following equation (2). The angle θ can be calculated using the following equation (6).

[0025]

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[0026]

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[0027]

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[0028]

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[0029]

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[0030]

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[0031] For example, when a ball 4 with a diameter of 8.73 mm is accommodated in an elliptical pocket 6 with a major axis diameter of 12 mm and a minor axis diameter of 8.83 mm, according to formula (3), the ball 4 contacts the pocket forming surface 7 of the cage 5 when it moves 0.61 mm in the circumferential direction relative to the cage 5 (c=0.61). Furthermore, according to formulas (4) and (5), the coordinates (m, n) of the contact point between the ball 4 and the pocket forming surface 7 at this time are m=1.33 and n=4.31. Then, by substituting c=0.61, m=1.33, and n=4.31 into formula (6), θ=80.5° is obtained, which satisfies the numerical condition for the angle θ described above.

[0032] As described above, when balls 4 with a diameter of 8.73 mm are accommodated in elliptical pockets 6 with a major axis diameter of 12 mm and a minor axis diameter of 8.83 mm, a relatively large circumferential gap Gb is formed between the pocket-forming surface 7 of the cage 5 (cage 5 in a neutral state) and the balls 4, as shown in FIG. 3 . The larger the circumferential gap Gb, the weaker the retention ability of the cage 5 (pockets 6) for the balls 4, which may result in unstable behavior of the balls 4 during bearing operation. Furthermore, if the circumferential gap Gb is large, the portion (pillar portion) of the cage 5 located between two circumferentially adjacent pockets 6 becomes thin, thereby reducing the strength of the cage 5. Therefore, the major axis diameter of the pockets 6 may be shortened to a degree that ensures the minimum necessary circumferential gap Gb, as illustrated in FIG. 5 , as long as the numerical condition for the angle θ is satisfied. The amount of shortening of the major axis diameter must be smaller than the absolute value of the displacement c calculated using Equation (3).

[0033] 6(a) shows a schematic longitudinal cross-sectional view of the rolling bearing 1, with the rotation axis RA of the ball 4 indicated. The surface speed relative to the rotation of the ball 4 is calculated by multiplying the angular velocity ω by the distance Da from the rotation axis RA to the surface of the ball 4, so the speed is fastest where the ball 4 contacts both raceway surfaces 2b and 3b, and gradually slows down along the rotation axis RA.

[0034] Figure 6(b) shows a conceptual diagram of the ball 4 (halved ball 4) arranged on a coordinate system with the origin at the center of the ball. As shown in Figure 2, when the ball 4 is in contact with both raceway surfaces 2b and 3b with a contact angle α, the angle that the rotation axis RA of the ball 4 makes with the line x (x-axis) that passes through the center of the ball and extends in the axial direction is α, so the rotation axis RA can be expressed as y = -(tan α)x.

[0035] Furthermore, if the diameter of ball 4 is d, the coordinates of the intersections of the surface of ball 4 with the x-axis, y-axis, and z-axis are (±d / 2, 0, 0), (0, ±d / 2, 0), and (0, 0, ±d / 2), respectively. The y-axis can be said to be a line extending radially through the center of the ball, and the z-axis can be said to be a line extending circumferentially through the center of the ball. When ball 4 moves circumferentially relative to cage 5 as rolling bearing 1 operates, points A and B at which ball 4 contacts cage 5 (its pocket-forming surface), and β is the angle between the line connecting point A (B) and the ball center and the z-axis (line z). The coordinates of point A can be expressed as (-(d / 2) sin β, 0, (d / 2) cos β), and the coordinates of point B can be expressed as ((d / 2) sin β, 0, (d / 2) cos β). In this case, the distance L between y=-(tan α)x representing the rotation axis RA and points A and B can be expressed by the following equation (7).

[0036]

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[0037] where: (a) When α=15° and angle β is changed within the range of 0° to 90°, (b) When α = 20° and the angle β is changed within the range of 0° to 90°, (c) When α=30° and angle β is changed within the range of 0° to 90°, The distance L was determined for each of the cases, and then the distance L was divided by (d / 2) to calculate the speed ratio relative to the case where θ=0° (when the ball 4 makes contact at the fastest part of its surface speed). For each of the cases (a), (b), and (c), line graphs are shown in Figures 7(a) to (c), with the angle β on the horizontal axis and the speed ratio on the vertical axis. The angle β shown in Figure 6(b) and Figures 7(a) to (c) corresponds to the "angle θ" referred to in the present invention.

[0038] 7(a), which shows the case where α = 15°, it can be seen that when angle β (= θ) is set to 60° or more, the rotational speed (surface speed) of ball 4 at contact points A and B with cage 5 can be reduced to 55% or less of the fastest portion of the surface speed of ball 4 (the surface speed of ball 4 at contact points with both raceway surfaces 2b and 3b). Also, when angle β is set to 20°, it can be reduced to 60% or less of the fastest portion of the surface speed of ball 4 at contact points A and B. When angle β is set to 60° or more, it can be reduced to 70% or less of the fastest portion of the surface speed of ball 4 at contact points A and B. When angle β is set to 30°, it can be reduced to 70% or less of the fastest portion of the surface speed of ball 4.

[0039] In short, according to the rolling bearing 1 of this embodiment, when the balls 4 come into contact with the pocket forming surface 7 of the cage 5 as the cage 5 and the balls 4 move relative to each other in the circumferential direction during operation, the rotational speed (surface speed) of the balls 4 at the point of contact can be appropriately suppressed, thereby reducing the frictional energy that occurs when the two come into contact. This makes it possible to prevent, as much as possible, the occurrence of the high-speed whirl phenomenon of the cage 5 that is caused by this frictional energy.

[0040] The gist of the present invention is to limit the contact positions (contact points) of the balls 4 with the pocket forming surface 7 of the cage 5 to a predetermined range on the pocket forming surface 7. This can be achieved, for example, by devising the shape of the pocket 6. Specifically, this can be achieved by configuring the pocket 6 as an elliptical hole with its major axis aligned circumferentially and its minor axis aligned axially. In this case, the formation and processing of the pocket 6 does not require any significant complication. Furthermore, unlike the rolling bearing of Patent Document 1, the rolling bearing 1 of this embodiment does not intentionally cause the cage 5 to be eccentric (in contact with) the raceways (inner ring 2 and outer ring 3). Therefore, there is no need to perform time-consuming and costly processing such as precision polishing on the cage 5 or the raceways. Therefore, the rolling bearing 1 of this embodiment can be realized at significantly lower cost than the rolling bearing of Patent Document 1.

[0041] The high-speed whirl phenomenon does not occur in all rotational speed ranges, but only in a specific rotational speed range. That is, in rotational speed ranges lower than the rotational speed range in which the high-speed whirl phenomenon occurs, the frictional energy generated by contact between the balls 4 and the cage 5 (the pocket forming surface 7 thereof) is small and is suppressed by viscous damping acting on the cage 5, and therefore the frictional energy generated by contact between the balls 4 and the cage 5 does not reach the level of displacing the cage 5 in the manner shown in Figures 8(a) and 8(b). On the other hand, in rotational speed ranges higher than the rotational speed range in which the high-speed whirl phenomenon occurs, the inertial force of the cage 5 becomes large, and it is presumed that the whirl of the cage 5 transitions to a whirl with the same period as the rotation of the cage 5.

[0042] As explained above, even if the contact points of the balls 4 with the pocket forming surface 7 of the cage 5 are changed, the inertial force of the cage 5 does not change significantly, and therefore the boundary value on the high-speed side of the region where the high-speed whirl phenomenon occurs does not change. However, if the contact points of the balls 4 and the cage 5 are changed during bearing operation, it becomes possible to reduce the frictional energy caused by contact between them, and therefore it is possible to raise the boundary value on the low-speed side of the region where the high-speed whirl phenomenon occurs and narrow the rotational speed region where the high-speed whirl phenomenon occurs.

[0043] Furthermore, the results of tests conducted to date have shown that the occurrence of the high-speed whirl phenomenon can be suppressed at a rotational speed approximately twice the rotational speed at which the high-speed whirl phenomenon begins to occur. Therefore, if the friction speed at the contact point between the pocket forming surface 7 of the cage 5 and the balls 4 can be reduced to approximately half, the low-speed boundary value of the high-speed whirl phenomenon occurrence range can be approximately doubled to exceed the high-speed boundary value, and it is believed that it will be possible to prevent the occurrence of the high-speed whirl phenomenon across the entire rotational speed range.

[0044] The rolling bearing 1 according to an embodiment of the present invention has been described above, but the embodiment of the present invention is not limited to this, and various modifications can be made within the scope that does not deviate from the gist of the present invention.

[0045] As described above, the present invention can prevent the occurrence of high-speed whirl in the cage 5 constituting the rolling bearing 1, and is therefore particularly suitable for use in rolling bearings used in applications where the high-speed whirl is likely to occur. For example, when a ball bearing is used as a rolling bearing to support the main spindle of a machine tool or the reaction wheel of a spacecraft, the ball bearing is subjected to a relatively large axial preload during use. Specifically, the ratio of the radial load Fr to the axial load Fa (= Fr / Fa) applied during operation is often 3 or less, making the high-speed whirl particularly likely to occur in such cases. This is because the more uniform the spacing between the rolling elements (balls), the more likely the high-speed whirl is to occur. Conversely, when the radial load acting on the ball bearing is significantly greater than the axial load (for example, when the above ratio Fr / Fa exceeds 3), lead and lag occur among the balls, resulting in uneven ball spacing, making the high-speed whirl less likely to occur. Therefore, the present invention can be particularly suitably applied to ball bearings used in applications where the relationship Fr / Fa≦3.0 holds, such as support bearings for the main spindles of machine tools and reaction wheels of space equipment. [Explanation of symbols]

[0046] 1. Rolling bearings 2. Inner circle 3 outer ring 4 balls (rolling elements) 5 Cage 6 pockets 7 Pocket forming surface Gb Circumferential clearance L1 straight line RA rotation axis α Contact angle, tilt of rotation axis θ angle

Claims

1. The bearing comprises a pair of raceways that are arranged radially opposite to each other and rotate relative to each other via a plurality of rolling elements, and an annular cage that has a plurality of pockets formed at intervals in the circumferential direction and that individually accommodate the rolling elements, In a rolling bearing in which a circumferential clearance is formed between the pocket forming surface of the cage and the rolling elements in a neutral state, A rolling bearing characterized in that when the rolling element moves circumferentially relative to the retainer in a neutral state, the contact point of the rolling element with the pocket forming surface is positioned at a position where the angle θ formed by a line connecting the contact point and the center of the rolling element with a plane that passes through the center of the rolling element and is perpendicular to the axial direction is 60° or more and less than 90°.

2. 2. The rolling bearing according to claim 1, wherein the pocket is formed as an elliptical hole whose major axis is arranged along the circumferential direction and whose minor axis is arranged along the axial direction.

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