Rolling bearing and rotary machine

Abstract

One of a pair of seal members (7, 8) is an outer ring fixed seal member (7) fixed to the inner periphery of an outer ring (2), the other is an inner ring fixed seal member (8) fixed to the outer periphery of an inner ring (3); an oil supply gap (23) for introducing a lubricant supplied from the outside of a bearing into a bearing space (4) is formed between the inner periphery of the outer ring fixed seal member (7) and the outer periphery of the inner ring (3); and an oil discharge gap (29) for discharging the lubricant from the bearing space (4) is formed between the outer periphery of the inner ring fixed seal member (8) and the inner periphery of the outer ring (2).

Description

Rolling bearings and rotating machinery

[0001] The present invention relates to a rolling bearing and a rotary machine equipped with the same.

[0002] [Background of the First Invention] Rolling bearings are often used as bearings that support rotating shafts in automobiles, industrial machinery, etc. (For example, see Patent Documents 1 and 2.) The rolling bearings in Patent Documents 1 and 2 include an outer ring, an inner ring disposed radially inward of the outer ring, a plurality of rolling elements incorporated in an annular bearing space formed between the outer ring and the inner ring, and a pair of seal members that respectively cover one axial end opening and the other axial end opening of the bearing space.

[0003] In the rolling bearing of Patent Document 1, a pair of seal members are both outer ring stationary seal members fixed to the inner periphery of the outer ring, and a labyrinth gap is formed between the inner periphery of the outer ring stationary seal member and the outer periphery of the inner ring. This rolling bearing lubricates the interior of the bearing by introducing lubricating oil supplied from outside the bearing into the bearing space through the labyrinth gap between the inner periphery of the outer ring stationary seal member and the outer periphery of the inner ring.

[0004] On the other hand, the rolling bearing of Patent Document 2 employs a configuration in which a pair of seal members are both fixed to the outer periphery of the inner ring, with a radial gap formed between the outer periphery of the inner ring and the inner periphery of the outer ring. Because this rolling bearing has a pair of seal members that rotate integrally with the inner ring, centrifugal force causes lubricating oil inside the bearing to move radially outward and be discharged to the outside of the bearing through the radial gap between the outer periphery of the inner ring and the inner periphery of the outer ring. This makes it difficult for lubricating oil to accumulate inside the bearing, minimizing the agitation resistance of the lubricating oil inside the bearing.

[0005] [Background of the second invention] A rolling bearing comprises an inner member including a first raceway surface, an outer member including a second raceway surface, a plurality of rolling elements arranged between the raceway surfaces, and a cage that holds the rolling elements.

[0006] When a rolling bearing rotates at high speed, if there is a certain amount of oil at the entrance of the elastic fluid contact between the rolling elements and the raceway, the oil film thickness does not increase any further, resulting in sufficient lubrication.It is known that if the amount of oil supplied to the rolling bearing is insufficient during high-speed rotation, the oil film thickness between the rolling elements and the raceway becomes thinner, a phenomenon known as starvation lubrication, and rolling viscous resistance decreases (Non-Patent Documents 1 to 3).

[0007] When rotating a rolling bearing at high speed using an oil lubrication system, it is common to use an open bearing that does not have a seal, shield, etc., as in the test examples in Non-Patent Documents 1 and 2, with the inner member located on the rotating part side of the rotating machine and the outer member located on the housing side of the rotating machine, and to provide the rotating machine with an oil supply unit that supplies oil to the side of the rolling bearing.

[0008] In the test examples of open bearings disclosed in Non-Patent Documents 1 and 2, it is shown that when the oil supply amount is 70 ml / min or 100 ml / min, sufficient lubrication is maintained up to the maximum bearing rotation speed of the test conditions, but when the oil supply amount is 40 ml / min, starvation occurs at bearing rotation speeds lower than the maximum bearing rotation speed of the test conditions.

[0009] In the air-oil lubrication system used in machine tool spindles, the oil supply unit can independently control the small amount of oil supplied with high precision, so by adjusting the amount of oil supplied according to the bearing rotation speed, it is possible to stabilize the starvation state to the extent that the oil film between the rolling elements and the raceway surface does not break down, thereby actively reducing friction torque. Non-Patent Document 3 discloses a calculation method for theoretically estimating friction torque when the amount of oil supplied is small, as in the air-oil lubrication system.

[0010] Japanese Patent Application Laid-Open No. 2013-060957 DE102020112044A1

[0011] Toyama, "Lubrication Analysis of High-Speed ​​Deep Groove Ball Bearings (1st Report) -Evaluating the Impact of Oil Supply Volume by Lubrication Visualization-", Tribology Conference 2023 Spring, Tokyo, Proceedings, pp. 240-244. Toyama, "Lubrication Analysis of High-Speed ​​Deep Groove Ball Bearings (2nd Report) -Evaluating the Impact of Oil Supply Volume by Lubrication Visualization-", Tribology Conference 2023 Spring, Tokyo, Proceedings, pp. 245-246. Fujiwara, "Method for Estimating Friction Torque of Air-Oil Lubricated Angular Contact Ball Bearings. Lubrication Analysis of High-Speed ​​Deep Groove Ball Bearings (1st Report) -Evaluating the Impact of Oil Supply Volume by Lubrication Visualization-", NTN TECHNICAL REVIEW No. 82 (2014), pp. 54-60.

[0012] [Problem of the First Invention] In recent years, in the field of electric vehicles such as EVs (battery electric vehicles) and HEVs (hybrid electric vehicles), efforts have been made to increase the rotation speed of electric motors in order to reduce the size and weight of the electric motors.

[0013] When the rolling bearing of Patent Document 1 is used in such high-speed rotation applications, the lubricating oil introduced through the labyrinth gap between the inner periphery of the outer ring stationary seal member and the outer periphery of the inner ring tends to accumulate inside the bearing, and the stirring resistance of the lubricating oil that has accumulated inside the bearing increases the problem of increased rotational resistance of the bearing.

[0014] Therefore, it is conceivable to use the rolling bearing of Patent Document 2 in order to reduce the stirring resistance of the lubricating oil inside the bearing, but if the rolling bearing of Patent Document 2 is used in an application requiring high-speed rotation, the lubricating oil inside the bearing will be expelled to the outside of the bearing by centrifugal force through the radial gap between the outer periphery of the inner ring fixed seal member and the inner periphery of the outer ring, which could cause a shortage of lubricating oil inside the bearing, resulting in abnormal heat generation, peeling damage, seizure, etc.

[0015] The problem to be solved by the first invention is to provide a rolling bearing that is less likely to suffer from a shortage of lubricating oil inside the bearing during high-speed rotation, and that can minimize the stirring resistance of the lubricating oil inside the bearing.

[0016] [Problem of the Second Invention] Energy conservation is now a major concern, and low torque is required for rolling bearings. Therefore, the amount of oil supplied is limited to a small amount to suppress agitation resistance. When a small amount of oil is supplied to the sides of an open bearing, the small amount of oil mixes with the atmosphere surrounding the bearing and enters the bearing. This causes air curtains to form on both sides of the open bearing during high-speed rotation. An air curtain is a phenomenon in which a lubricating fluid, such as oil, swirls in the circumferential direction and spreads to the sides as a result of the high-speed rotating cage and multiple rolling elements revolving at high speeds stirring the lubricating fluid. If the force of the air curtain is strong, it becomes difficult for the oil supplied to the sides of the open bearing to penetrate the annular space of the rolling bearing. This reduces the amount of oil that contributes to lubricating and cooling the rolling elements, resulting in starvation.

[0017] However, in applications where rolling bearing failure tolerance is important, high-speed rotation under sufficient lubrication is sometimes required. In the case of rotating machinery equipped with an oil supply unit capable of precisely controlling the amount of oil supplied, such as air-oil lubrication, sufficient lubrication can be maintained by increasing the amount of oil supplied from the oil supply unit based on control that takes into account increases in bearing rotation speed and the effects of air curtains. However, there are cases where it is not possible to adopt such an oil supply unit with a control function. For example, in the case of an electric axle unit (so-called e-Axle) that integrates an electric motor, gear reducer, and inverter for vehicle drive, the rotational speeds during operation differ significantly between the motor shaft or input shaft of the reducer and the second and subsequent transmission shafts of the reducer. Therefore, the desired amount of oil supplied differs between the rolling bearings supporting the high-speed shaft, such as the input shaft, and the rolling bearings supporting the second and subsequent transmission shafts. Providing a dedicated oil supply unit with a control function for oil lubrication of the rolling bearings supporting the high-speed shaft would result in an increase in the size and complexity of the unit, making it unacceptable. In such an operating environment, it is not possible to meet the demand for higher rotational speeds by raising the bearing rotational speed at which starvation occurs (i.e., the upper limit of the bearing rotational speed at which sufficient lubrication can be maintained).

[0018] In view of the above background, the problem that the second invention aims to solve is to increase the bearing rotation speed at which starvation occurs without requiring an electric axle unit or the like to be larger or more complex.

[0019] In order to solve the above problems, a first invention provides a rolling bearing having the following configuration: [Configuration 1] A rolling bearing having an outer ring, an inner ring arranged radially inward of the outer ring, a plurality of rolling elements installed in an annular bearing space formed between the outer ring and the inner ring, and a pair of seal members covering one axial end opening and the other axial end opening of the bearing space, one of the pair of seal members is an outer ring stationary seal member fixed to the inner periphery of the outer ring, and the other is an inner ring stationary seal member fixed to the outer periphery of the inner ring, an oil discharge gap for discharging lubricating oil from the bearing space is formed between the outer periphery of the inner ring stationary seal member and the inner periphery of the outer ring, and an oil supply gap for introducing lubricating oil supplied from outside the bearing into the bearing space is formed between the inner periphery of the outer ring stationary seal member and the outer periphery of the inner ring.

[0020] When this configuration is adopted, the inner ring stationary seal member rotates integrally with the inner ring, causing the lubricating oil inside the bearing to move radially outward due to centrifugal force and be discharged to the outside of the bearing through the oil discharge gap between the outer periphery of the inner ring stationary seal member and the inner periphery of the outer ring. As a result, the lubricating oil is less likely to accumulate inside the bearing, and it is possible to keep the stirring resistance of the lubricating oil inside the bearing low.

[0021] Furthermore, because the outer ring stationary seal member does not rotate even when the inner ring rotates, lubricating oil inside the bearing is discharged through the oil drain gap by centrifugal force, and lubricating oil supplied from outside the bearing can be drawn into the interior of the bearing through the oil supply gap between the inner periphery of the outer ring stationary seal member and the outer periphery of the inner ring. As a result, there is little shortage of lubricating oil inside the bearing during high-speed rotation, ensuring stable lubrication inside the bearing.

[0022] Furthermore, because the lubricating oil inside the bearing is simultaneously discharged to the outside of the bearing through the oil discharge gap between the outer periphery of the inner ring stationary seal member and the inner periphery of the outer ring, and the lubricating oil supplied from outside the bearing is drawn into the inside of the bearing through the oil supply gap between the inner periphery of the outer ring stationary seal member and the outer periphery of the inner ring, the lubricating oil inside the bearing is constantly replaced, ensuring smooth heat exchange within the bearing and making it possible to effectively suppress temperature increases during high-speed rotation.

[0023] [Configuration 2] A rolling bearing according to Configuration 1, wherein the outer ring fixed seal member has a rubber seal lip with a plurality of convex portions provided at intervals in the circumferential direction and in sliding contact with the outer periphery of the inner ring via an oil film, and the oil supply gap is a gap formed between circumferentially adjacent convex portions.

[0024] With this configuration, the oil supply gap is a gap formed between circumferentially adjacent convex portions of the seal lip, and so the size of the oil supply gap can be controlled with high precision by adjusting the height of the convex portions of the seal lip. This allows the size of the oil supply gap to be set small, making it possible to effectively prevent foreign matter from entering the interior of the bearing from outside the bearing through the oil supply gap.

[0025] [Configuration 3] The rolling bearing according to Configuration 2, wherein a cylindrical seal sliding surface is formed on the outer periphery of the inner ring, the cylindrical seal sliding surface extending in the axial direction from a portion with which the seal lip slides and connecting to an axial end face of the inner ring.

[0026] When this configuration is adopted, the seal sliding surface on the outer periphery of the inner ring is cylindrical, extending axially from the location where the seal lip slides and connecting to the axial end face of the inner ring, so that the oil supply gap between the seal lip and the inner ring is more widely exposed to the outside of the bearing than when the seal lip slides against the inner surface of the recessed groove, allowing lubricating oil supplied from outside the bearing to be smoothly introduced into the oil supply gap.

[0027] [Configuration 4] A rolling bearing according to Configuration 3, wherein a cylindrical seal fixing surface is formed on the outer periphery of the inner ring into which the radially inner end of the inner ring stationary seal member is fitted and fixed, and the seal fixing surface and the seal sliding surface have symmetrical shapes and the same outer diameter, thereby making the shape of the inner ring symmetrical with respect to a plane perpendicular to the axis.

[0028] When this configuration is adopted, the seal fixing surface and the seal sliding surface can be machined in the same process when manufacturing the inner ring, resulting in low costs, and also excellent workability because there is no need to distinguish between the front and back sides of the inner ring when assembling the rolling bearing.

[0029] [Configuration 5] The rolling bearing according to any one of Configurations 1 to 4, wherein the inner ring stationary seal member is a metallic shield plate that does not contact the inner periphery of the outer ring.

[0030] When this configuration is adopted, the inner ring stationary seal member does not come into contact with the inner periphery of the outer ring, making it possible to keep the rotational resistance of the bearing small.

[0031] [Configuration 6] A rolling bearing according to any one of Configurations 1 to 5, wherein the inner ring fixed seal member has a cylindrical fitting portion that fits onto the outer periphery of the inner ring, an annular plate portion that rises radially outward from the cylindrical fitting portion, and a bent edge portion that is formed by bending a radially outer end of the annular plate portion axially inward.

[0032] With this configuration, the inner ring stationary seal member has a bent edge formed by bending the radially outer end of the annular plate portion inward in the axial direction, so that when lubricating oil drawn into the bearing from the oil supply gap between the inner circumference of the outer ring stationary seal member and the outer circumference of the inner ring moves radially outward due to centrifugal force, some of the lubricating oil is received by the bent edge of the inner ring stationary seal member before it reaches the oil drain gap between the outer circumference of the inner ring stationary seal member and the inner circumference of the outer ring, and can be retained inside the bearing. This prevents the lubricating oil drawn into the bearing from the oil supply gap from being discharged in excess through the oil drain gap.

[0033] [Configuration 7] A rolling bearing according to Configuration 6, wherein a circumferential groove is formed on the inner circumference of the outer ring, extending circumferentially at a position corresponding to the inner ring stationary seal member, and at least a part of the bent edge portion of the inner ring stationary seal member is housed in the circumferential groove.

[0034] With this configuration, at least a portion of the bent edge of the inner ring stationary seal member is housed in a circumferential groove formed on the inner circumference of the outer ring, so that lubricating oil from inside the bearing that moves along the inner circumference of the outer ring toward the inner ring stationary seal member can be efficiently captured by the bent edge, thereby making it possible to effectively prevent excessive discharge of lubricating oil from inside the bearing through the oil drain gap.

[0035] [Configuration 8] A rolling bearing according to Configuration 7, wherein an inner circumference of the outer ring forms a seal fixing groove into which a radially outer end of the outer ring fixed seal member is fitted and fixed, and the cross-sectional shape of the seal fixing groove and the cross-sectional shape of the circumferential groove are symmetrical, thereby making the shape of the outer ring symmetrical with respect to a plane perpendicular to the axis.

[0036] When this configuration is adopted, the seal fixing groove and circumferential groove can be machined in the same process when manufacturing the outer ring, resulting in low costs, and also excellent workability when assembling the rolling bearing because there is no need to distinguish between the front and back sides of the outer ring.

[0037] [Configuration 9] The rolling bearing according to any one of Configurations 1 to 8, wherein grease is sealed in the bearing space.

[0038] By adopting this configuration, it is possible to ensure lubrication inside the bearing during the initial period of use of the bearing until lubricating oil is supplied from outside the bearing.

[0039] To solve the above problem, a second invention provides a rolling bearing having the following configuration: [Configuration 10] A rolling bearing comprising an inner member having a first raceway surface, an outer member having a second raceway surface, a plurality of rolling elements arranged between the first raceway surface and the second raceway surface, and a cage that holds the plurality of rolling elements, further comprising: a shield that protrudes from the inner diameter surface of the outer member toward the outer diameter surface of the inner member at a position spaced apart from the rolling elements and the cage on one axial side, and a slinger that protrudes from the outer diameter surface of the inner member toward the inner diameter surface of the outer member at a position spaced apart from the rolling elements and the cage on the other axial side opposite to the one axial side, wherein a first oil vent port is formed between the shield and the inner member, and a second oil vent port is formed between the slinger and the outer member.

[0040] With this configuration, when the inner member rotates and the rolling bearing rotates, the shield receives the lubricating fluid such as oil that is agitated by the rolling elements and cage and flows toward one axial side, reducing the effect of the air curtain on the side surface on that axial side of the rolling bearing and making it easier for the oil supplied to that axial side of the rolling bearing to reach the first oil vent between the shield and the inner member. Meanwhile, on the other axial side of the rolling bearing, the slinger exerts a centrifugal force on the oil that has lubricated and cooled the rolling elements, facilitating the discharge of the oil from the second oil vent between the outer member and the slinger and reducing the back pressure of the second oil vent relative to the first oil vent, making it easier for the oil to be sucked in through the first oil vent. By reducing the effect of the air curtain on one axial side of the rolling bearing while promoting oil discharge on the other axial side of the rolling bearing, it is possible to prevent oil from flowing back through the first oil vent, and to exert a centrifugal pumping action by drawing oil drawn in through the first oil vent toward the second oil vent, lubricating and cooling the rolling elements, etc., and discharging the oil from the second oil vent. Increasing the bearing rotational speed strengthens this centrifugal pumping action. In this way, if the rolling bearing is equipped with a shield and slinger that exerts an effective centrifugal pumping action at high rotational speeds, the bearing rotational speed at which starvation occurs can be increased by the rolling bearing itself, without requiring the electric axle unit, etc. to be larger or more complex.

[0041] [Configuration 11] The rolling bearing according to Configuration 10, wherein the cage has an annular portion extending circumferentially on the other axial side relative to the plurality of rolling elements, and the slinger has a side plate portion facing a side surface on the other axial side of the annular portion with an axial gap therebetween.

[0042] By adopting this configuration, oil can be made to flow between the annular portion of the retainer and the side plate portion of the slinger, and centrifugal action can be applied to the oil from both locations to prevent it from escaping from this gap, thereby sending it to the second oil passage port.

[0043] [Configuration 12] The rolling bearing according to Configuration 11, wherein the slinger has a cylindrical plate portion fitted into the inner member so as to face the annular portion with a radial gap therebetween, the side plate portion protruding radially outward from the other axial side of the cylindrical plate portion, and the radial gap between the cylindrical plate portion and the annular portion is smaller than the axial gap between the side surface of the other axial side of the annular portion and the side plate portion.

[0044] By adopting this configuration, it becomes difficult for oil to pass between the annular portion of the retainer and the cylindrical plate portion of the slinger, making it easier to supply oil to the rolling elements between the inner circumference of the retainer and the inner member, where the oil tends to become relatively diluted when the rolling bearing rotates at high speeds.

[0045] [Configuration 13] The rolling bearing according to Configuration 11 or 12, wherein the radial distance between the outer peripheral edge of the side plate portion and the outer member is set larger than the axial distance between the side surface of the annular portion on the other axial side and the side plate portion.

[0046] By adopting this configuration, oil that has passed between the annular portion of the cage and the side plate portion of the slinger can be easily discharged from the second oil passage port.

[0047] [Configuration 14] The rolling bearing according to Configuration 13, wherein the outer member has a shoulder portion facing the annular portion with a gap therebetween in the radial direction, and a notch portion provided at a position facing the side plate portion in the radial direction and having a larger diameter than the shoulder portion, and the side plate portion has an outer diameter smaller than that of the shoulder portion.

[0048] By adopting this configuration, the second oil vent port can be expanded radially by the cutout portion of the outer member, preventing the side plate portion of the slinger from becoming smaller in diameter, and oil that passes between the outer member and the outer periphery of the retainer can be made to flow more easily toward the second oil vent port.

[0049] [Configuration 15] The rolling bearing according to any one of Configurations 10 to 14, wherein the inside diameter of the shield is set to be equal to or smaller than the inside diameter of the cage.

[0050] When this configuration is adopted, the entire retainer and most of the rolling elements are covered by the shield from one axial side, so that most of the oil that is stirred by the retainer and rolling elements and flows toward one axial side is received by the shield and prevented from flowing back into the first oil passage.

[0051] [Configuration 16] The rolling bearing according to any one of Configurations 10 to 15, wherein the cage is provided at a position farther away from the shield in the other axial direction than the rolling elements.

[0052] When this configuration is adopted, a large space is provided between the shield and the rolling elements, so that the oil can be diffused in the space between them and easily reach the rolling elements.

[0053] [Configuration 17] A rolling bearing according to any one of Configurations 10 to 16, wherein the shield has a tip plate portion that is closest to the inner member within the shield, and an inner diameter side tapered plate portion that extends in a direction inclined radially outward from one axial side of the tip plate portion.

[0054] By adopting this configuration, oil supplied to one axial side of the rolling bearing can easily enter the first oil passage port, and oil received by the shield can easily reach the rolling elements.

[0055] [Configuration 18] A rolling bearing according to any one of Configurations 10 to 17, wherein the cage is made of a resin member having an annular portion extending in the circumferential direction, and multiple pairs of claw portions extending from the annular portion to one axial side so as to form spaces that are open radially inward, radially outward, and to one axial side, the rolling elements are made of balls arranged in the spaces, the spaces between the claw portions located between circumferentially adjacent rolling elements are recessed toward the other axial side, and wherein a is the minimum axial thickness from a concave end face located furthest to the other axial side between the claw portions to a side surface of the cage on the other axial side, b is the axial thickness from a pocket bottom located furthest to the other axial side in the space to a side surface of the cage on the other axial side, and c is the minimum distance between an imaginary plane passing through the centers of the multiple rolling elements and the concave end face, so that a > b and c > 0 are satisfied.

[0056] By adopting this configuration, deformation of the cage due to centrifugal force during high-speed rotation is suppressed, making the rolling bearing a ball bearing suitable for high-speed rotation applications.

[0057] [Configuration 19] A rotary machine comprising: the rolling bearing according to any one of configurations 10 to 18; a rotating part supported by said rolling bearing; and an oil supply part that supplies oil to one axial side of said rolling bearing.

[0058] By adopting this configuration, oil can be sucked in through the first oil inlet when the rolling bearing is rotating at high speed, so that the bearing rotation speed at which starvation occurs can be increased and the rotating part can be operated at high speed without the need for an oil supply section that can precisely control the amount of oil supplied.

[0059] In the rolling bearing of the first invention, the inner ring stationary seal member rotates integrally with the inner ring, so that the lubricating oil inside the bearing moves radially outward due to centrifugal force and is discharged to the outside of the bearing through the oil discharge gap between the outer periphery of the inner ring stationary seal member and the inner periphery of the outer ring. As a result, the lubricating oil is less likely to accumulate inside the bearing, and it is possible to keep the stirring resistance of the lubricating oil inside the bearing low.

[0060] Furthermore, because the outer ring stationary seal member does not rotate even when the inner ring rotates, lubricating oil inside the bearing is discharged through the oil drain gap by centrifugal force, and lubricating oil supplied from outside the bearing can be drawn into the interior of the bearing through the oil supply gap between the inner periphery of the outer ring stationary seal member and the outer periphery of the inner ring. As a result, there is little shortage of lubricating oil inside the bearing during high-speed rotation, ensuring stable lubrication inside the bearing.

[0061] Furthermore, because the lubricating oil inside the bearing is simultaneously discharged to the outside of the bearing through the oil discharge gap between the outer periphery of the inner ring stationary seal member and the inner periphery of the outer ring, and the lubricating oil supplied from outside the bearing is drawn into the inside of the bearing through the oil supply gap between the inner periphery of the outer ring stationary seal member and the outer periphery of the inner ring, the lubricating oil inside the bearing is constantly replaced, ensuring smooth heat exchange within the bearing and making it possible to effectively suppress temperature increases during high-speed rotation.

[0062] The second aspect of the present invention increases the bearing rotation speed at which starvation occurs without requiring an electric axle unit or the like to be larger or more complex.

[0063] FIG. 2 is an enlarged cross-sectional view of the vicinity of the outer ring stationary seal member of FIG. 1; FIG. 3 is a cross-sectional view taken along line III-III of FIG. 2; FIG. 4 is an enlarged cross-sectional view of the vicinity of the inner ring stationary seal member of FIG. 1; FIG. 5 is a view showing a modified example of the bent portion of the inner ring stationary seal member shown in FIG. 4; FIG. 6 is a view showing another modified example of the bent portion of the inner ring stationary seal member shown in FIG. 4; FIG. 7 is a view showing yet another modified example of the bent portion of the inner ring stationary seal member shown in FIG. 4; FIG. 8 is a cross-sectional view taken along line XI-XI of FIG. 1;

[0064] 1 shows a rolling bearing 1 according to a first embodiment of the present invention. This rolling bearing 1 comprises an outer ring 2, an inner ring 3 arranged coaxially radially inward of the outer ring 2, a plurality of rolling elements 5 spaced circumferentially in an annular bearing space 4 formed between the outer ring 2 and the inner ring 3, a cage 6 that maintains the circumferential spacing of the plurality of rolling elements 5, and a pair of seal members 7, 8 that cover one axial end opening and the other axial end opening of the bearing space 4. One of the pair of seal members 7, 8 is an outer ring fixed seal member 7 fixed to the inner periphery of the outer ring 2, and the other is an inner ring fixed seal member 8 fixed to the outer periphery of the inner ring 3. Grease for initial lubrication is sealed in the bearing space 4.

[0065] The inner circumference of the outer ring 2 is formed with an outer ring raceway groove 9 with which the rolling elements 5 roll, a pair of outer ring shoulders 10 located axially outward of the outer ring raceway groove 9, a seal fixing groove 11 located axially outward of one of the pair of outer ring shoulders 10 (the left outer ring shoulder 10 in the figure), and a circumferential groove 12 located axially outward of the other of the pair of outer ring shoulders 10 (the right outer ring shoulder 10 in the figure). The outer ring raceway groove 9 is an arcuate groove with a concave arc-shaped cross section that conforms to the surface of the rolling elements 5 and is formed to extend circumferentially through the axial center of the inner circumference of the outer ring 2. The pair of outer ring shoulders 10 are bank-shaped portions that extend circumferentially on both sides of the outer ring raceway groove 9 in the axial direction. The radially outer end of the outer ring stationary seal member 7 is fitted into and fixed in the seal fixing groove 11.

[0066] The outer periphery of the inner ring 3 is formed with an inner ring raceway groove 13 with which the rolling elements 5 make rolling contact, a pair of inner ring shoulders 14 located axially outward of the inner ring raceway groove 13, a seal sliding surface 15 (see FIG. 2 ) located axially outward of one of the pair of inner ring shoulders 14 (the left inner ring shoulder 14 in the figure), and a seal fixing surface 16 located axially outward of the other of the pair of inner ring shoulders 14 (the right inner ring shoulder 14 in the figure). The inner ring raceway groove 13 is an arcuate groove with a concave arc-shaped cross section that conforms to the surface of the rolling elements 5 and is formed to extend circumferentially through the axial center of the outer periphery of the inner ring 3. The pair of inner ring shoulders 14 are bank-shaped portions extending circumferentially on both sides of the inner ring raceway groove 13 in the axial direction. The radially inner end of the inner ring stationary seal member 8 is fitted and fixed to the seal fixing surface 16.

[0067] The rolling elements 5 are sandwiched radially between the outer ring raceway groove 9 and the inner ring raceway groove 13. This rolling bearing 1 is a deep groove ball bearing. That is, the outer ring raceway groove 9 is an arc-shaped groove symmetrical about the axial center of the outer ring 2, and the inner ring raceway groove 13 is also an arc-shaped groove symmetrical about the axial center of the inner ring 3.

[0068] As shown in Figure 2, the outer ring fixed seal member 7 is made of an annular plate-shaped core metal 17 and rubber 18 vulcanization-bonded to the core metal 17. The core metal 17 is formed by press-forming a steel plate such as a cold-rolled steel plate or a stainless steel plate. The rubber 18 has an outer peripheral rubber portion 19 extending radially outward from the radially outer end of the core metal 17, an outer surface rubber portion 20 covering the entire axially outer side surface of the core metal 17, and a seal lip 21 extending radially inward from the radially inner end of the core metal 17.

[0069] The outer peripheral rubber portion 19 fits into the seal fixing groove 11 on the inner circumference of the outer ring 2. The seal lip 21 is in sliding contact with the seal sliding surface 15 on the outer circumference of the inner ring 3. The seal sliding surface 15 is a cylindrical surface that extends in the axial direction with a constant outer diameter from the location with which the seal lip 21 slides and connects to the axial end face 22 of the inner ring 3. An oil supply gap 23 is formed between the inner circumference of the seal lip 21 and the seal sliding surface 15, which introduces lubricating oil supplied from outside the bearing into the bearing space 4.

[0070] As shown in FIG. 3 , the inner periphery of the seal lip 21 is formed with a plurality of convex portions 24 spaced apart in the circumferential direction, and a lip inner circumferential surface 25 connecting adjacent convex portions 24 in the circumferential direction. The convex portions 24 are arranged at equal intervals around the entire inner periphery of the seal lip 21. The height of each convex portion 24 (the distance from the lip inner circumferential surface 25 to the seal sliding surface 15 when the tip of the convex portion 24 is in contact with the seal sliding surface 15) is set to 0.1 mm or less. Each convex portion 24 is formed to extend in a direction intersecting the circumferential direction (for example, a direction perpendicular to the circumferential direction (a direction perpendicular to the plane of the paper in the figure)). The oil supply gap 23 is a gap formed between adjacent convex portions 24 in the circumferential direction.

[0071] Each protrusion 24 is formed so that its cross section along the circumferential direction exhibits a convex arc shape, and is in sliding contact with the seal sliding surface 15 via an oil film due to the wedge film effect. In other words, when the seal sliding surface 15 on the outer periphery of the inner ring 3 moves circumferentially relative to each protrusion 24, lubricating oil present between circumferentially adjacent protrusions 24 is introduced along the surface of each protrusion 24 and into the space between the protrusion 24 and the seal sliding surface 15. At this time, the wedge film effect ensures that the lubrication state between each protrusion 24 and the seal sliding surface 15 is fluid lubrication, making it possible to keep the sliding resistance (seal torque) of the seal lip 21 low.

[0072] 4 , the inner ring fixed seal member 8 is a metal shield plate formed by press-forming a metal plate (e.g., a steel plate) and is provided so as not to contact the inner circumference of the outer ring 2. The inner ring fixed seal member 8 has a cylindrical fitting portion 26 that fits onto the outer circumference of the inner ring 3, an annular plate portion 27 that rises radially outward from the cylindrical fitting portion 26, and a bent rim portion 28 formed by bending the radial outer end of the annular plate portion 27 axially inward (to the left in the figure).

[0073] The cylindrical fitting portion 26 is fixed by fitting with an interference to the seal fixing surface 16 on the outer periphery of the inner ring 3. The seal fixing surface 16 is a cylindrical surface that extends in the axial direction with a constant outer diameter and connects to the axial end face 22 of the inner ring 3. The seal fixing surface 16 has the same outer diameter as the seal sliding contact surface 15 (see Figure 2) and has a symmetrical shape, so that the inner ring 3 has a symmetrical shape with respect to an imaginary axis-perpendicular plane that passes through the axial center of the inner ring 3, as shown in Figure 1.

[0074] The circumferential groove 12 on the inner circumference of the outer ring 2 extends circumferentially at a position corresponding to the inner ring stationary seal member 8, and at least a portion (all of it in the figure) of the bent rim portion 28 is housed within it. The bent rim portion 28 is a cylindrical portion extending axially inward from the radial outer end of the annular plate portion 27, and its inner diameter is larger than the inner diameter of the outer ring shoulder 10. An oil drain gap 29 that drains lubricating oil from the bearing space 4 is formed between the outer periphery of the bent rim portion 28 and the inner periphery of the outer ring 2. The oil drain gap 29 is a minute annular gap (see FIG. 11 ).

[0075] The cross-sectional shape of the circumferential groove 12 is symmetrical to the cross-sectional shape of the seal fixing groove 11 (see FIG. 3 ), and as a result, as shown in FIG. 1 , the outer ring 2 has a symmetrical shape with respect to an imaginary axis-perpendicular plane passing through the axial center of the outer ring 2.

[0076] As shown in Figure 12, this rolling bearing 1 is used in an inner ring rotation application, rotatably supporting a rotating shaft 34 while attached to a fixed housing 33. The rotating shaft 34 is, for example, the rotating shaft to which rotation from the electric motor of an electric vehicle is input, or the rotating shaft of a hybrid electric vehicle that uses an electric motor as an auxiliary driving force for the engine. The housing 33 is provided with a lubricating oil supply passage 35 that supplies lubricating oil to the rolling bearing 1 from one axial side.

[0077] 1, in this rolling bearing 1, the inner ring stationary seal member 8 rotates integrally with the inner ring 3, so that the lubricating oil inside the bearing moves radially outward due to centrifugal force and is discharged to the outside of the bearing through an oil discharge gap 29 between the outer periphery of the inner ring stationary seal member 8 and the inner periphery of the outer ring 2. As a result, the lubricating oil is less likely to accumulate inside the bearing, and it is possible to keep the stirring resistance of the lubricating oil inside the bearing low.

[0078] Furthermore, because the outer ring fixed seal member 7 does not rotate even when the inner ring 3 rotates, the lubricating oil inside the bearing is discharged from the oil drain gap 29 by centrifugal force, and lubricating oil supplied from outside the bearing can be drawn into the interior of the bearing through the oil supply gap 23 between the inner periphery of the outer ring fixed seal member 7 and the outer periphery of the inner ring 3. As a result, the lubricating oil inside the bearing is less likely to run short during high-speed rotation, ensuring stable lubrication inside the bearing.

[0079] Furthermore, because the lubricating oil inside the bearing is simultaneously discharged to the outside of the bearing through the oil discharge gap 29 between the outer periphery of the inner ring stationary seal member 8 and the inner periphery of the outer ring 2, and the lubricating oil supplied from outside the bearing is drawn into the inside of the bearing through the oil supply gap 23 between the inner periphery of the outer ring stationary seal member 7 and the outer periphery of the inner ring 3, the lubricating oil inside the bearing is constantly replaced, ensuring smooth heat exchange within the bearing. This makes it possible to effectively suppress temperature increases during high-speed rotation.

[0080] Furthermore, in this rolling bearing 1, as shown in Figure 3, the oil supply gap 23 is a gap formed between circumferentially adjacent convex portions 24 of the seal lip 21, so the gap dimension of the oil supply gap 23 can be controlled with high precision by adjusting the height of the convex portions 24 of the seal lip 21. This allows the gap dimension of the oil supply gap 23 to be set small, making it possible to effectively prevent foreign matter from entering the interior of the bearing from outside the bearing through the oil supply gap 23.

[0081] 2 , in this rolling bearing 1, the seal sliding surface 15 on the outer periphery of the inner ring 3 is cylindrical, extending axially from the portion where the seal lip 21 slides to connect to the axial end face 22 of the inner ring 3, so that the oil supply gap 23 between the seal lip 21 and the inner ring 3 is more widely exposed to the outside of the bearing than when the seal lip 21 slides against the inner surface of the recessed groove. This allows lubricating oil supplied from outside the bearing to be smoothly introduced into the oil supply gap 23.

[0082] Furthermore, in this rolling bearing 1, as shown in Fig. 4, the inner ring stationary seal member 8 has a bent edge portion 28 formed by bending the radially outer end of the annular plate portion 27 inward in the axial direction, so that when lubricating oil drawn into the interior of the bearing from the oil supply gap 23 between the inner periphery of the outer ring stationary seal member 7 and the outer periphery of the inner ring 3 moves radially outward due to centrifugal force, some of the lubricating oil is received by the bent edge portion 28 of the inner ring stationary seal member 8 before it reaches the oil discharge gap 29 between the outer periphery of the inner ring stationary seal member 8 and the inner periphery of the outer ring 2, and can be retained inside the bearing, as shown in Fig. 4. This makes it possible to prevent the lubricating oil drawn into the interior of the bearing from the oil supply gap 23 shown in Fig. 1 from being excessively discharged through the oil discharge gap 29.

[0083] Furthermore, in this rolling bearing 1, as shown in Figure 4, at least part of the bent edge portion 28 of the inner ring stationary seal member 8 is housed in the circumferential groove 12 formed on the inner circumference of the outer ring 2, so that lubricating oil inside the bearing that moves along the inner circumference of the outer ring shoulder 10 toward the inner ring stationary seal member 8 (to the right in the figure) can be efficiently received by the bent edge portion 28. This makes it possible to effectively prevent excessive discharge of lubricating oil inside the bearing from the oil drain gap 29.

[0084] Furthermore, in this rolling bearing 1, by making the seal fixing surface 16 shown in Figure 4 and the seal sliding contact surface 15 shown in Figure 2 symmetrical in shape and with the same outer diameter, the shape of the inner ring 3 shown in Figure 1 is symmetrical with respect to the plane perpendicular to the axis, so that when manufacturing the inner ring 3, the seal fixing surface 16 and the seal sliding contact surface 15 can be machined in the same process, reducing cost. Furthermore, when assembling the rolling bearing 1, there is no need to distinguish between the front and back sides of the inner ring 3, resulting in excellent workability.

[0085] Furthermore, as shown in Figure 1, this rolling bearing 1 uses a metal shield plate that does not come into contact with the inner periphery of the outer ring 2 as the inner ring fixed seal member 8, making it possible to keep the rotational resistance of the bearing low.

[0086] Furthermore, in this rolling bearing 1, the cross-sectional shape of the seal fixing groove 11 shown in Fig. 2 is symmetrical to the cross-sectional shape of the circumferential groove 12 shown in Fig. 4, thereby making the shape of the outer ring 2 shown in Fig. 1 symmetrical with respect to the plane perpendicular to the axis, and therefore when manufacturing the outer ring 2, the seal fixing groove 11 and the circumferential groove 12 can be machined in the same process, reducing cost. Furthermore, when assembling the rolling bearing 1, there is no need to distinguish between the front and back sides of the outer ring 2, resulting in excellent workability.

[0087] In the above embodiment, as shown in Fig. 4 , the bent portion 28 formed by bending the radial outer end of the annular plate portion 27 axially inward has been described as being cylindrical and extending axially inward with a constant diameter from the radial outer end of the annular plate portion 27. However, as shown in Fig. 5 , a truncated cone-like portion whose diameter gradually increases axially inward from the radial outer end of the annular plate portion 27 may also be used. In Fig. 5 , the radially outer portion of the bent portion 28 is accommodated in a circumferential groove 12 on the inner circumference of the outer ring 2. Even when the configuration shown in Fig. 5 is adopted, lubricating oil inside the bearing that moves along the inner circumference of the outer ring shoulder 10 toward the inner ring stationary seal member 8 (to the right in the figure) can be efficiently captured by the bent portion 28, thereby effectively preventing excessive discharge of lubricating oil inside the bearing from the oil drain gap 29.

[0088] As the bent edge portion 28 formed by bending the radial outer end of the annular plate portion 27 inward in the axial direction, as shown in Figure 6, it may be one having a crank-shaped cross section consisting of a cylindrical portion 36 and an annular plate portion 37 extending radially outward from the tip of the cylindrical portion 36, or as shown in Figure 7, it may be one having a truncated cone shape whose diameter gradually decreases from the radial outer end of the annular plate portion 27 toward the axial inner side, as shown in Figure 8, it may be one that connects from the radial outer end of the annular plate portion 27 to a cylindrical portion 39 via a truncated cone portion 38, or as shown in Figure 9, it may be one that connects from the radial outer end of the annular plate portion 27 to a cylindrical portion 41 via an R portion 40 that has an arc-shaped cross section. In all of the modified examples shown in Figures 6 to 9, at least a portion of the bent edge portion 28 is housed in the circumferential groove 12 on the inner circumference of the outer ring 2, and therefore lubricating oil from inside the bearing that moves along the inner circumference of the outer ring shoulder 10 toward the inner ring stationary seal member 8 (to the right in the figure) can be efficiently received by the bent edge portion 28, making it possible to effectively prevent excessive discharge of lubricating oil from inside the bearing through the oil drainage gap 29 compared to when the entire bent edge portion 28 is positioned outside the circumferential groove 12 as shown in Figure 10.

[0089] In the above embodiment, an example was given in which rubber 18 was vulcanized and bonded to a core metal 17 as the outer ring fixed seal member 7, but a shield plate formed by press-forming a metal plate (for example, one with the inner diameter side and outer diameter side of the inner ring fixed seal member 8 in the above embodiment reversed) may also be used as the outer ring fixed seal member 7. In this case, a configuration can be used in which the inner circumference of the outer ring fixed seal member 7 does not come into sliding contact with the outer circumference of the inner ring 3, and an annular oil supply gap 23 is formed between the inner circumference of the outer ring fixed seal member 7 and the outer circumference of the inner ring 3.

[0090] Furthermore, while the above embodiment has given an example in which a shield plate formed by press-molding a metal plate is used as the inner ring fixed seal member 8, it is also possible to use rubber vulcanized and bonded to a core metal as the inner ring fixed seal member 8. In this case, for example, an inner ring fixed seal member 8 having a configuration in which the inner diameter side and outer diameter side of the outer ring fixed seal member 7 of the above embodiment are reversed can be used as the inner ring fixed seal member 8, and the gap between circumferentially adjacent convex portions 24 can be used as the oil drain gap 29.

[0091] A rolling bearing and a rotary machine according to an embodiment of the second invention will be described with reference to the accompanying drawings.

[0092] The rotating machine shown in Figure 13 comprises a housing 100, a rotating part 101 that rotates relative to the housing 100, a rolling bearing 50 that supports the rotating part 101 so that it can rotate freely relative to the housing 100, and an oil supply part 102 that supplies oil to the rolling bearing 50.

[0093] The rolling bearing 50 comprises an inner member 51, an outer member 52 surrounding the inner member 51, a plurality of rolling elements 53 housed between the inner member 51 and the outer member 52, a cage 54 that holds these rolling elements 53, a shield 55 attached to the outer member 52, and a slinger 56 attached to the inner member 51. The inner diameter of the rolling bearing 50 can be in the range of 30 mm to 45 mm, for example.

[0094] The rolling elements 53 , the cage 54 , the shield 55 and the slinger 56 are arranged in an annular space 57 formed by the outer periphery of the inner member 51 and the inner periphery of the outer member 52 .

[0095] Here, the direction along the bearing center axis of the rolling bearing 50 is referred to as the "axial direction," the direction perpendicular to the bearing center axis is referred to as the "radial direction," and the direction in which the circumference centered on the bearing center axis extends is referred to as the "circumferential direction." In addition, in the radial direction, the side closer to the bearing center axis is referred to as the "radially inner side," and conversely, the side away from the bearing center axis is referred to as the "radially outer side." In Figure 13, the axial direction corresponds to the left-right direction, and the radial direction corresponds to the up-down direction.

[0096] The housing 100 is made of a casing that is stationary relative to the rotating part 101. The rotating part 101 is made of a shaft that is rotated by input torque. For example, if the rotating machine is an electric axle unit for driving a vehicle, the rotating part 101 can be a motor shaft or a transmission shaft of a reducer, and the housing 100 can be a motor case or a reducer case.

[0097] The oil supply unit 102 supplies oil to one axial side of the rolling bearing 50. It reaches the outer periphery of one axial end of the inner member 51. In the illustrated example, a splash lubrication system is assumed, and the oil supply unit 102 is a tube that drops oil toward one axial side of the rolling bearing 50. If an oil bath lubrication system is adopted, the oil supply unit can be an oil bath that stores oil at an oil level that submerges the lower part of the rolling element 53 located at the lowest position in the orbital trajectory of the rolling element 53. The oil supply unit 102 may supply oil in liquid form, as in the oil bath lubrication system or splash lubrication system, or in mist form, as in the drop lubrication system or spray lubrication system. Note that in Figure 13, the movement of oil is schematically indicated by arrows without a reference symbol. The atmosphere surrounding the rolling bearing 50 is generally air. The amount of oil supplied from the oil supply portion 102 is small, and the oil and the atmosphere mix together and enter the annular space 57 to become a lubricating fluid that contributes to lubrication and cooling of the rolling elements 53 and the like.

[0098] The inner member 51 is made of a raceway ring including a first raceway surface 58 and a shoulder portion 59 on its outer periphery that defines the outer diameter of the inner member 51. The inner diameter surface of the inner member 51 is fitted into the rotating portion 101.

[0099] The outer member 52 is made of a raceway ring including, on its inner circumference, a second raceway surface 60, a shoulder 61 that defines the inner diameter of the outer member 52, a full-circumferential groove 62 formed at a position spaced apart from the second raceway surface 60 on one side in the axial direction, and a notch 63 provided at a position spaced apart from the second raceway surface 60 on the other side in the axial direction and with a larger diameter than the shoulder 61. The outer diameter surface of the outer member 52 is fitted into the housing 100.

[0100] The rolling elements 53 are balls that roll on a first raceway surface 58 and a second raceway surface 60 .

[0101] The rolling bearing 50 is configured as a deep groove ball bearing.

[0102] The maximum rotation speed of the rolling bearing 50 accompanying the rotation of the rotating part 101 is set to a dmn value of 650,000 or more. Here, the dmn value is [{outer diameter of the rolling bearing (mm) + inner diameter of the rolling bearing (mm)} / 2] × rotation speed n (min －１) The outer diameter of the rolling bearing 50 is determined by the outer diameter surface of the outer member 52. The inner diameter of the rolling bearing 50 is determined by the inner diameter surface of the inner member 51. The rotation speed n is determined by the number of rotations per minute of the inner member 51.

[0103] 13 and 14 , the cage 54 is made of a resin member having a seamless annular portion 64 extending circumferentially at a position on the other axial side (right side in FIG. 13 ) opposite one axial side of the plurality of rolling elements 53, and multiple pairs of claw portions 65, 66 extending from the annular portion 64 to one axial side. The pair of claw portions 65, 66 extends from the annular portion 64 so as to form spaces 67 that are open radially inward, radially outward, and to one axial side (left side in FIG. 13 ). The spaces 67 are arranged at equal intervals at multiple locations circumferentially of the cage 54.

[0104] As shown in Figures 13 to 15, the rolling elements 53 are arranged in spaces 67. One space 67 is formed by the opposing portions of a pair of claws 65, 66 that face each other in the circumferential direction with the rolling elements 53 interposed therebetween, and by a part of the annular portion 64. The pair of claws 65, 66 have tip portions that are located on one axial side of the center of the rolling elements 53. The minimum width of an opening formed in one axial side of the cage 54 by the tip portions of the pair of claws 65, 66 is smaller than the diameter of the rolling elements 53. The rolling elements 53 are arranged in the space by being forced to pass between the tip portions of the pair of claws 65, 66.

[0105] The annular portion 64 is disposed facing the shoulder portion 61 on the other axial side of the outer member 52 with a radial gap therebetween. A side surface 68 on the other axial side of the annular portion 64 is flat and extends radially, and is located furthest to the other axial side of the cage 54. The claw portions 65, 66 are located furthest to the one axial side of the cage 54. The axial length of the claw portions 65, 66 from the full-circumferential resin portion that forms the annular portion 64 is shorter than that of the rolling elements 53.

[0106] The cage 54 is guided in the radial and axial directions by the plurality of rolling elements 53. Therefore, as shown in FIG. 13 , the cage 54 is disposed in a state where it does not come into contact with the inner member 51, the outer member 52, the shield 55, and the slinger 56.

[0107] Most of the cage surface forming the space 67 follows an imaginary spherical surface and serves as a guide surface that can come into contact with the rolling elements 53. The geometric center O of the space 67 is the center of the imaginary spherical surface. In the drawing, the center O of the space 67 coincides with the center of the rolling elements 53. In addition, in Figure 15, the up-down direction corresponds to the axial direction, and the left-right direction corresponds to the circumferential direction.

[0108] 15, the claw portions 65, 66 include oil inlet passages 67a facing the space 67. The oil inlet passages 67a are flow paths that form groove spaces between the rolling elements 53 and the claw portions 65, 66, into which the rolling elements 53 cannot enter. During operation of the rolling bearing 50, oil enters between the oil inlet passages 67a and the rolling elements 53, thereby promoting lubrication and cooling of the rolling elements 53 and their surroundings.

[0109] The oil inlet passage 67a is located on an imaginary plane that passes through the centers of the multiple rolling elements 53. Because the rotation speed of the rolling elements 53 is fastest on or near this imaginary plane, it is preferable to provide the oil inlet passage 67a to promote lubrication.

[0110] As shown in Figures 14 and 15, the cage 54 has a recessed shape toward the other axial direction between two claw portions 65, 66 located between adjacent rolling elements 53 in the circumferential direction. Here, the minimum axial thickness from the recessed end surface 69 located farthest toward the other axial direction between the two claw portions 65, 66 to the side surface of the cage 54 on the other axial direction is defined as a. The axial thickness from the pocket bottom P located farthest toward the other axial direction in the space 67 to the side surface of the cage 54 on the other axial direction is defined as b. The minimum distance between the recessed end surface 69 and an imaginary plane passing through the centers of the rolling elements 53 is defined as c. The cage 54 satisfies a > b and c > 0. This ensures the ring strength of the cage 54 while reducing the mass of the claw portions 65, 66 and thereby reducing the centrifugal force acting on the claw portions 65, 66. This ultimately suppresses deformation of the cage 54 during high-speed rotation and prevents interference between the claw portions 65, 66 and other components, such as the rolling elements 53.

[0111] The resin material forming the cage 54 may be, for example, a material containing polyether ether ketone (PEEK) or polyphenylene sulfide (PPS) as a main component, or a composite material in which reinforcing fibers such as carbon or glass are mixed with an appropriate matrix resin. The axial thicknesses a, b, and c may be determined so as to satisfy a > b and c > 0 depending on the strength of the resin material forming the cage 54. For example, when polyamide resin is used as the main component of the resin material, setting the axial thickness b to 1 / 70 to 1 / 30 of the cage P.C.D. ensures rigidity at the relatively thin pocket bottom P and effectively prevents deformation during high-speed rotation. In this case, when the weld portion generated during injection molding of the cage 54 is located at the minimum axial thickness a, setting the minimum axial thickness a to 1 / 62 to 1 / 26 of the cage P.C.D. ensures strength at the weld portion. Note that the cage P.C.D. D refers to the diameter of an imaginary circle that passes through the center O of each space 67 and extends in the circumferential direction.

[0112] 13 , the shield 55 protrudes from the inner diameter surface of the outer member 52 toward the outer diameter surface of the inner member 51 at a position spaced apart on one axial side from the rolling elements 53 and the cage 54. A first oil passage port 70 is formed between the shield 55 and the inner member 51. The first oil passage port 70 is a space through which oil can pass between the shield 55 and the inner member 51, and serves as an inlet for sucking lubricating fluid such as oil that has reached the gap between the shield 55 and the inner member 51 from one axial side of the annular space 57 into a spatial region within the annular space 57 that is closer to the rolling elements 53 than the shield 55.

[0113] When rolling bearing 50 rotates with inner member 51 rotating, lubricating fluid such as oil is agitated by rolling elements 53 and cage 54, and the lubricating fluid such as oil flowing toward one axial side of rolling elements 53 and cage 54 is received by shield 55, thereby reducing the effect of an air curtain on the side surface on one axial side of rolling bearing 50. This makes it easier for oil supplied from oil supply section 102 to one axial side of rolling bearing 50 to reach first oil vent port 70.

[0114] The slinger 56 protrudes from the outer diameter surface of the inner member 51 toward the inner diameter surface of the outer member 52 at a position spaced apart on the other axial side from the rolling elements 53 and the cage 54. A second oil passage port 71 is formed between the slinger 56 and the outer member 52. The second oil passage port 71 is a space through which oil can pass between the slinger 56 and the outer member 52, and serves as an outlet for discharging lubricating fluid such as oil that has been sucked in through the first oil passage port 70 and then reached the other axial side of the rolling elements 53 and the cage 54 in the annular space 57 to the outside of the annular space 57.

[0115] Slinger 56 exerts a centrifugal action on lubricating fluid such as oil in annular space 57, facilitating the discharge of lubricating fluid such as oil from second oil vent port 71. As a result, the back pressure of second oil vent port 71 relative to first oil vent port 70 is suppressed. The pressure difference between first oil vent port 70 and second oil vent port 71 causes lubricating fluid such as oil that has lubricated and cooled rolling elements 53 and the like to be drawn toward second oil vent port 71, making it easier for oil supplied from oil supply unit 102 and atmosphere to be drawn through first oil vent port 70.

[0116] The shield 55 and the slinger 56 are each formed from a single metal plate. In this example, a steel plate is used as the metal plate. For example, the steel plate may be made of SPC material as specified in the JIS standard.

[0117] The shield 55 is composed of a curled plate portion 72 held in the circumferential groove portion 62 of the outer member 52, a tip plate portion 73 that is closest to the shoulder portion 59 on one axial side of the inner member 51 within the shield 55, an inner diameter side tapered plate portion 74 that extends in a direction inclined radially outward from one axial side of the tip plate portion 73, an intermediate plate portion 75 that extends radially from the inner diameter side tapered plate portion 74, and an outer diameter side tapered plate portion 76 that extends from the inner diameter side of the curled plate portion 72 to the intermediate plate portion 75 in a direction inclined axially to one side.

[0118] The shield 55 is attached to the outer member 52 by caulking the curled plate portion 72 into the circumferential groove portion 62 of the outer member 52 .

[0119] The tip plate portion 73 is disposed facing the shoulder portion 59 on one axial side of the inner member 51 with a radial gap therebetween. The inner periphery of the tip plate portion 73 defines the inner diameter of the shield 55. The inner diameter of the shield 55 is set to be equal to or smaller than the inner diameter of the cage 54. Therefore, the entire cage 54 is covered from one axial side by the shield 55. When the rolling bearing 50 rotates, most of the lubricating fluid such as oil that is agitated by the rolling elements 53 and the cage 54 and flows toward one axial side is received by the shield 55.

[0120] The inner diameter side tapered plate portion 74 extends in a direction inclined radially outward from the tip plate portion 73, which defines the inner diameter of the shield 55, toward one axial side, so that the space between the inner diameter side tapered plate portion 74 and the shoulder portion 59 is larger than the space between the tip plate portion 73 and the shoulder portion 59 on one axial side of the inner member 51. Therefore, oil supplied from the oil supply portion 102 can easily enter the first oil port 70 from between the inner diameter side tapered plate portion 74 and the shoulder portion 59.

[0121] The tip plate portion 73 has a cylindrical shape that extends circumferentially with a certain length in the axial direction from the inner diameter side tapered plate portion 74. Therefore, the lubricating fluid such as oil that enters the first oil passage port 70 is likely to flow along the inner periphery of the tip plate portion 73 and the shoulder portion 59 toward the rolling elements 53.

[0122] The distance between the shield 55 and the cage 54 is greater than the distance between the shield 55 and the rolling elements 53. By disposing the annular portion 64 on the other axial side of the rolling elements 53, the cage 54 is located farther axially from the shield 55 than the rolling elements 53. Since the annular portion 64 is not present between the shield 55 and the rolling elements 53, the space between the shield 55 and the rolling elements 53 is relatively wide. Therefore, lubricating fluid such as oil sucked through the first oil passage 70 enters and diffuses into the relatively wide space between the shield 55 and the rolling elements 53, making it easier to reach the rolling elements 53. Furthermore, the agitated lubricating fluid such as oil is obstructed by the annular portion 64, reducing the flow rate toward the other axial side, and increasing the flow rate toward one axial side in the relatively wide space. When the lubricating fluid such as oil flowing toward one axial side is received by the shield 55, it changes direction and diffuses into the relatively wide space. When the lubricating fluid such as oil received by the shield 55 flows toward the outer member 52, it is guided by the outer diameter side tapered plate portion 76, making it easier to reach the rolling elements 53. Furthermore, when the lubricating fluid such as oil received by the shield 55 flows toward the inner member 51, it combines with the lubricating fluid such as oil that enters the relatively large space between the shield 55 and the rolling elements 53 from the first oil passage port 70, and is guided by the inner diameter side tapered plate portion 74 and the tip plate portion 73, making it easier to reach the rolling elements 53.

[0123] The slinger 56 is composed of a cylindrical plate portion 77 fitted to the outer periphery of the other axial side of the inner member 51, and a side plate portion 78 protruding radially outward from the other axial side of the cylindrical plate portion 77.

[0124] The slinger 56 is attached to the inner member 51 by press-fitting the cylindrical plate portion 77 into the inner member 51 .

[0125] The cylindrical plate portion 77 is disposed facing the inner periphery of the annular portion 64 with a gap therebetween in the radial direction. The side plate portion 78 is disposed facing the side surface 68 on the other axial side of the annular portion 64 with a gap therebetween in the axial direction.

[0126] Because the cylindrical plate portion 77 is located between the inner member 51 and the annular portion 64, the radial distance g1 between the cylindrical plate portion 77 and the annular portion 64 is narrower than the radial distance between the annular portion 64 and the inner member 51. Lubricating fluid such as oil that attempts to enter between the annular portion 64 and the cylindrical plate portion 77 from near the rolling elements 53 is obstructed by the cylindrical plate portion 77, making it difficult for it to pass between the annular portion 64 and the cylindrical plate portion 77. When the rolling bearing 50 rotates at high speed, the centrifugal action is strong, causing lubricating fluid such as oil that comes into contact with the outer periphery of the cage 54, the outer periphery of the inner member 51, the slinger 56, etc. to be sent radially outward by centrifugal force, so that the lubricating fluid such as oil is unevenly distributed toward the outer member 52, and the oil tends to become diluted between the cage 54 and the inner member 51. Therefore, it becomes difficult for lubricating fluid such as oil to pass between the annular portion 64 and the cylindrical plate portion 77 from the vicinity of the rolling element 53, which is advantageous for lubrication and cooling of the rolling element 53 and the first raceway surface 58.

[0127] The radial distance g1 between the cylindrical plate portion 77 and the annular portion 64 is set smaller than the axial distance g2 between the side plate portion 78 and the side surface 68 on the other axial side of the annular portion 64. Therefore, the flow path cross-sectional area between the side plate portion 78 and the side surface 68 on the other axial side of the annular portion 64 is larger than the flow path cross-sectional area between the cylindrical plate portion 77 and the annular portion 64.

[0128] The entire amount of lubricating fluid, such as oil, that has passed between the cylindrical plate portion 77 and the annular portion 64 toward the other axial side enters between the side plate portion 78 and the side surface 68 on the other axial side of the annular portion 64. At this time, the lubricating fluid is guided by the side plate portion 78 and changes its flow direction radially outward. Furthermore, when the lubricating fluid, such as oil, moves from between the cylindrical plate portion 77 and the annular portion 64, which has a relatively narrow flow path cross section, to between the side plate portion 78 and the side surface 68 on the other axial side of the annular portion 64, which has a relatively wide flow path cross section, the velocity of the lubricating fluid moving radially outward increases as the pressure decreases. This increase in velocity makes it easier for the lubricating fluid, such as oil, that has passed between the side plate portion 78 and the side surface 68 on the other axial side of the annular portion 64 to be discharged from the second oil vent port 71.

[0129] Furthermore, between the side surface 68 on the other axial side of the annular portion 64 and the side plate portion 78, the lubricating fluid such as oil that comes into contact with the side surface 68 or the side plate portion 78 is sent radially outward by centrifugal force. The lubricating fluid such as oil that comes into contact with the side surface 68 or the side plate portion 78 cannot escape from between the side surface 68 and the side plate portion 78, and centrifugal action is exerted by both portions 68, 78 from the side surface 68 or the side plate portion 78 to the second oil vent port 71 that is thrown out radially outward from the side surface 68 or the side plate portion 78.

[0130] If the axial distance g2 between the side surface 68 on the other axial side of the annular portion 64 and the side plate portion 78 is too wide, the flow of lubricating fluid such as oil will be disturbed between the side surface 68 and the side plate portion 78, reducing the efficiency of sending the lubricating fluid such as oil by centrifugal force. For this reason, the axial distance g2 is set to, for example, 1 mm or more and 3 mm or less.

[0131] The radial distance g3 between the outer peripheral edge of the side plate portion 78 and the outer member 52 is set larger than the axial distance g2 between the side surface 68 on the other axial side of the annular portion 64 and the side plate portion 78. Therefore, the flow path cross-sectional area between the outer peripheral edge of the side plate portion 78 and the outer member 52 is larger than the flow path cross-sectional area between the side surface 68 on the other axial side of the annular portion 64 and the side plate portion 78.

[0132] When a lubricating fluid such as oil that has passed radially outward between the side plate portion 78 and the side surface 68 on the other axial side of the annular portion 64 moves from the gap between the side plate portion 78 and the side surface 68 on the other axial side of the annular portion 64, which has a relatively narrow flow passage cross section, to the gap between the outer peripheral edge of the side plate portion 78, which has a relatively wide flow passage cross section, and the outer member 52, the speed of the lubricating fluid that moves radially outward increases as the pressure decreases. Therefore, the lubricating fluid such as oil that has passed radially outward between the side plate portion 78 and the side surface 68 on the other axial side of the annular portion 64 is more likely to be discharged from the second oil vent port 71.

[0133] The notch 63 of the outer member 52 is provided with a larger diameter than the shoulder 61 at a position radially opposite the side plate 78, so that the second oil vent port 71 is provided wider radially outward, thereby avoiding the need to reduce the outer diameter of the side plate 78. This allows the space axially opposite the side plate 78 and the side surface 68 on the other axial side of the annular portion 64 to expand radially outward, which is advantageous for strengthening the centrifugal action described above.

[0134] Because the annular portion 64 faces the shoulder portion 61 of the outer member 52 with a radial gap therebetween and the side plate portion 78 has a smaller diameter than the shoulder portion 61, lubricating fluid such as oil flowing from the vicinity of the rolling elements 53 toward the other axial side between the shoulder portion 61 and the outer periphery of the cage 54 can reach the second oil vent port 71 without colliding with the side plate portion 78 in the axial direction. Therefore, the lubricating fluid such as oil that has passed between the outer member 52 and the outer periphery of the cage 54 is more likely to head toward the second oil vent port 71. Consequently, the lubricating fluid such as oil present near the second oil vent port 71 is more likely to be discharged from the second oil vent port 71. Note that in the illustrated example, in order to maximize the centrifugal action between the side plate portion 78 and the side surface 68 on the other axial side of the annular portion 64, the outer diameter of the side plate portion 78 is set to be equal to the outer diameter of the annular portion 64.

[0135] Lubricating fluid such as oil that has passed between the side surface 68 on the other axial side of the annular portion 64 and the side plate portion 78 joins with lubricating fluid such as oil that has passed between the annular portion 64 and the shoulder portion 61 to the other axial side, and is discharged from the second oil vent port 71. When the rolling bearing 50 is rotating at high speed, if the force of the lubricating fluid such as oil that has passed between the side surface 68 and the side plate portion 78 is strong, it may reach the notch portion 63. The lubricating fluid such as oil that has reached this point collides with the notch portion 63 and spreads, heading toward the second oil vent port 71, or is guided by the notch portion 63 and turns counterclockwise in the figure between the notch portion 63 and the outer periphery of the annular portion 64, heading toward the second oil vent port 71. Even if a lubricating fluid such as oil hits the notch portion 63, the notch portion 63 forms a radial step with respect to the shoulder portion 61, so that the fluid is prevented from moving toward the gap between the shoulder portion 61 and the outer periphery of the annular portion 64.

[0136] The other axial side surface of the side plate portion 78 comes into contact with the atmosphere surrounding the rolling bearing 50. When the inner member 51 rotates, causing the rolling bearing 50 to rotate, the atmosphere in contact with the other axial side surface of the side plate portion 78 is sent radially outward by centrifugal force. This flow blows and reduces the pressure of the fluid present near the second oil vent port 71 outside the annular space 57, thereby encouraging the discharge of lubricating fluid such as oil from the second oil vent port 71.

[0137] When the rolling bearing 50 is configured as a ball bearing, whether or not there is sufficient lubrication between the rolling elements 53 and the raceway surfaces 58, 59 when the amount of oil sucked in from the first oil inlet 70 is small can be examined, for example, using the test results shown in Non-Patent Documents 1 and 2 and the reduction in rolling viscous resistance φr based on the knowledge of the method for estimating friction torque shown in Non-Patent Document 3.

[0138] Here, the reduction in rolling viscous resistance φr is a value calculated by the following equation 1. T: Ball (rolling element) passing period (msec) ν: Oil dynamic viscosity (mm ２ / s) a: Long axis radius of contact ellipse (mm) k: Oil amount (ml / min)

[0139] According to the test examples in Non-Patent Documents 1 and 2, sufficient lubrication was maintained up to the maximum speed under test conditions with oil supply rates of 70 ml / min and 100 ml / min, while starvation occurred at speeds lower than the maximum speed under test conditions with an oil supply rate of 40 ml / min. The reduction in rolling viscous resistance φr under each test condition was calculated as φr = 0.288 under the test condition with an oil supply rate of 40 ml / min, φr = 0.505 under the test condition with an oil supply rate of 70 ml / min, and φr = 0.721 under the test condition with an oil supply rate of 100 ml / min. Therefore, it is believed that sufficient lubrication can be maintained when φr ≧ 0.505 is satisfied.

[0140] That is, the amount of oil sucked in from the first oil inlet 70 is taken as the value of k, the dynamic viscosity of the oil in the usage environment is taken as the value of ν, the passage period of the rolling element 53 when the rolling bearing 50 has the desired dmn value in the usage environment is taken as the value of T, and the major axis radius of the contact ellipse at the contact point between the rolling element 53 and the first raceway surface 58 or the second raceway surface 60 in the usage environment is taken as the value of a, and φr is calculated; for example, if φr≧0.505 is satisfied when the dmn value of the rolling bearing 50 is a predetermined value of 650,000 or more, it is considered that sufficient lubrication can be maintained at that predetermined value.

[0141] The rolling bearing 50 shown in Figures 13 to 15 is as described above, and comprises an inner member 51 having a first raceway surface 58, an outer member 52 having a second raceway surface 60, a plurality of rolling elements 53 arranged between the first raceway surface 58 and the second raceway surface 60, and a cage 54 that holds the plurality of rolling elements 53.

[0142] This rolling bearing 50 further includes, in particular, a shield 55 that protrudes from the inner diameter surface of the outer member 52 toward the outer diameter surface of the inner member 51 at a position spaced apart on one axial side (left side in FIG. 13 ) from the rolling elements 53 and the cage 54, and a slinger 56 that protrudes from the outer diameter surface of the inner member 51 toward the inner diameter surface of the outer member 52 at a position spaced apart on the other axial side (right side in FIG. 13 ) from the rolling elements 53 and the cage 54, with the space between the shield 55 and the inner member 51 forming a first oil vent 70 for sucking oil, and the space between the slinger 56 and the outer member 52 forming a second oil vent 71 for discharging the oil sucked in from the first oil vent 70. As a result, when the rolling bearing 50 rotates with the inner member 51 rotating, the lubricating fluid such as oil that is stirred by the rolling elements 53 and retainer 54 and flows toward one axial side is received by the shield 55, reducing the effect of the air curtain on the side surface on one axial side of the rolling bearing 50, making it easier for the oil supplied to one axial side of the rolling bearing 50 to reach the first oil inlet 70, while on the other axial side of the rolling bearing 50, a centrifugal action is exerted by the slinger 56 on the oil that has lubricated and cooled the rolling elements 53, promoting the discharge of the oil from the second oil inlet 71, and ultimately reducing the back pressure of the second oil inlet 71 on the first oil inlet 70, making it easier to suck oil through the first oil inlet 70. This rolling bearing 50, by virtue of the effect of reducing the influence of these air curtains and the effect of suppressing the back pressure of the second oil vent port 71 relative to the first oil vent port 70, prevents oil from flowing back through the first oil vent port 70, and exerts a centrifugal pumping action by drawing oil drawn in through the first oil vent port 70 toward the second oil vent port 71 and discharging the oil that has lubricated and cooled the rolling elements 53 and the like from the second oil vent port 71. Increasing the dmn value (bearing rotational speed) of this rolling bearing 50 strengthens its centrifugal pumping action. In this way, since this rolling bearing 50 is equipped with the shield 55 and slinger 56 for exerting an effective centrifugal pumping action during high-speed rotation, the bearing rotational speed at which starvation occurs can be increased without requiring an electric axle unit or other unit to be larger or more complex.

[0143] Furthermore, in this rolling bearing 50, the retainer 54 has an annular portion 64 that extends circumferentially on the other axial side relative to the multiple rolling elements 53, and the slinger 56 has a side plate portion 78 that faces a side surface 68 on the other axial side of the annular portion 64 with an axial gap between them, so that oil flows into the space between the annular portion 64 and the side plate portion 78, and centrifugal action is exerted on the oil from both portions 68, 78 to prevent it from escaping from this space, and the oil can be sent to the second oil inlet 71.

[0144] In addition, this rolling bearing 50 has a tubular plate portion 77 fitted into the inner member 51 so that the slinger 56 faces the annular portion 64 with a radial gap between them, and the side plate portion 78 protrudes radially outward from the other axial side of the tubular plate portion 77. The radial spacing g1 between the tubular plate portion 77 and the annular portion 64 is smaller than the axial spacing g2 between the side surface 68 on the other axial side of the annular portion 64 and the side plate portion 78. This makes it difficult for oil to pass between the annular portion 64 and the tubular plate portion 77, making it easier to supply oil to the rolling elements 53 between the inner circumference of the retainer 54 and the inner member 51, where oil is likely to become relatively diluted when the rolling bearing 50 rotates at high speed.

[0145] Furthermore, in this rolling bearing 50, the radial distance g3 between the outer peripheral edge of the side plate portion 78 and the outer member 52 is set to be larger than the axial distance g2 between the side surface 68 on the other axial side of the annular portion 64 and the side plate portion 78, making it easier for oil that has passed through between the side surface 68 on the other lateral side of the annular portion 64 and the side plate portion 78 to be discharged from the second oil inlet 71.

[0146] In addition, this rolling bearing 50 has a shoulder portion 61 in which the outer member 52 faces the annular portion 64 with a radial gap therebetween, and a notch portion 63 that is provided at a position radially opposite the side plate portion 78 and has a larger diameter than the shoulder portion 61.Since the side plate portion 78 is provided with a smaller diameter than the shoulder portion 61, the notch portion 63 radially widens the second oil passage port 71, preventing the side plate portion 78 from becoming smaller in diameter, and makes it easier for oil that has passed between the outer member 52 and the outer periphery of the retainer 54 to flow toward the second oil passage port 71.

[0147] Furthermore, in this rolling bearing 50, the inner diameter of the shield 55 is set to be equal to or smaller than the inner diameter of the retainer 54, so that the entire retainer 54 and most of the rolling elements 53 are covered from one axial side by the shield 55. As a result, most of the oil that is stirred by the retainer 54 and the rolling elements 53 and flows toward one axial side is received by the shield 55, preventing it from flowing back into the first oil inlet 70.

[0148] Furthermore, in this rolling bearing 50, the retainer 54 is positioned further axially from the shield 55 than the rolling element 53, which leaves a wider space between the shield 55 and the rolling element 53, allowing oil to diffuse in the space between the two elements 55 and 53, making it easier for the oil to reach the rolling element 53.

[0149] Furthermore, in this rolling bearing 50, the shield 55 has a tip plate portion 73 that is closest to the inner member 51 within the shield 55, and an inner diameter side tapered plate portion 74 that extends in a direction inclined radially outward from one axial side of the tip plate portion 73, making it easier for oil supplied to one axial side of the rolling bearing 50 to enter the first oil inlet 70 and making it easier for the oil received by the shield 55 to reach the rolling body 53.

[0150] In addition, in this rolling bearing 50, the cage 54 is made of a resin member having an annular portion 64 extending in the circumferential direction and multiple pairs of claw portions 65, 66 extending from the annular portion 64 to one axial side so as to form a space 67 that is open radially inward, radially outward, and to one axial side, the rolling elements 53 are made of balls arranged in the space 67, the spaces between the claw portions 65, 66 located between adjacent rolling elements 53 in the circumferential direction are recessed toward the other axial side, and a recessed end surface 69 located furthest to the other axial side between the claw portions 65, 66 extends from the other axial side of the cage 54. When the minimum axial thickness from the pocket bottom P located furthest to the other axial side of the retainer 54 (side surface 68 on the other axial side of the annular portion 64) is a, the axial thickness from the pocket bottom P located furthest to the other axial side of the retainer 54 (side surface 68 on the other axial side of the annular portion 64) in the space 67 is b, and the minimum distance between an imaginary plane passing through the centers of the multiple rolling elements 53 and the concave end surface 69 is c, since a > b and c > 0 are satisfied, deformation of the retainer 54 due to centrifugal force during high-speed rotation is suppressed, and the rolling bearing 50 can be made into a ball bearing suitable for high-speed rotation applications.

[0151] Furthermore, the rotating machine according to the embodiment is equipped with a rolling bearing 50, a rotating part 101 supported by the rolling bearing 50, and an oil supply part 102 that supplies oil to one axial side of the rolling bearing 50, so that oil can be sucked in from the first oil inlet 70 when the rolling bearing 50 rotates at high speed. This means that the bearing rotation speed at which starvation occurs can be increased and the rotating part 101 can be operated at high speed without having to be equipped with an oil supply part that can precisely control the amount of oil supplied.

[0152] In this embodiment, an example has been shown in which the space from the first oil vent port 70 to the rolling elements 53 passes directly in the axial direction, but a circumferential groove may be formed on the outer periphery of one axial end of the inner member, and a labyrinth gap may be formed between the circumferential groove and the tip plate of the shield. Also, although an example has been shown in which the shield 55 is made of a metal plate, it may also be a seal having an elastomer seal lip, and for example, a non-contact seal may be configured in which the seal lip is arranged so as to form a labyrinth gap between the seal lip and the circumferential groove of the inner member as described above, or the core metal of the seal may have a shape corresponding to that of the shield 55.

[0153] It is also possible to position the annular portion of the cage on one axial side relative to the rolling elements. In this case, the annular portion prevents lubricating fluid, such as oil, stirred by the rolling elements from moving toward the first oil vent, which is advantageous in reducing the effect of the air curtain. However, this is disadvantageous in that the annular portion prevents oil drawn from the first oil vent from reaching the rolling elements, and the increased distance between the slinger and the cage makes it difficult for the lubricating fluid, such as oil, to move toward the second oil vent, even if the slinger exerts a centrifugal force on the lubricating fluid, thereby weakening the centrifugal pumping effect. Therefore, the position of the annular portion of the cage relative to the rolling elements can be determined by taking these advantages and disadvantages into consideration.

[0154] Furthermore, the present invention can be applied to angular contact ball bearings and roller bearings in addition to deep groove ball bearings.

[0155] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims.

[0156] REFERENCE SIGNS LIST 1 Rolling bearing 2 Outer ring 3 Inner ring 4 Bearing space 5 Rolling elements 7 Outer ring stationary seal member 8 Inner ring stationary seal member 11 Seal fixing groove 12 Circumferential groove 15 Seal sliding surface 16 Seal fixing surface 21 Seal lip 22 Axial end face 23 Oil supply gap 24 Convex portion 26 Fitting cylindrical portion 27 Annular plate portion 28 Bent edge portion 29 Oil drain gap 50 Rolling bearing 51 Inner member 52 Outer member 53 Rolling elements 54 Cage 55 Shield 56 Slinger 58 First raceway surface 60 Second raceway surface 61 Shoulder portion 63 Notch portion 64 Annular portion 65, 66 Pawl portion 67 Space 68 Side surface on the other axial side 69 Concave end face 70 First oil passage port 71 Second oil passage port 73 Tip plate portion 74 Inner diameter side tapered plate portion 77 Cylindrical plate portion 78 Side plate portion 101 Rotating portion 102 Oil supply portion

Claims

1. A rolling bearing having an outer ring (2), an inner ring (3) arranged radially inward of the outer ring (2), a plurality of rolling elements (5) incorporated in an annular bearing space (4) formed between the outer ring (2) and the inner ring (3), and a pair of seal members (7, 8) respectively covering one axial end opening and the other axial end opening of the bearing space (4), wherein one of the pair of seal members (7, 8) is an outer ring fixed seal member (7) fixed to the inner circumference of the outer ring (2), and the other is an inner ring fixed seal member (8) fixed to the outer circumference of the inner ring (3), and an oil supply gap (23) is formed between the inner circumference of the outer ring fixed seal member (7) and the outer circumference of the inner ring (3) to introduce lubricating oil supplied from outside the bearing into the bearing space (4), a drainage gap (29) for draining lubricating oil from the bearing space (4) is formed between the outer periphery of the inner ring fixed seal member (8) and the inner periphery of the outer ring (2).

2. A rolling bearing as described in claim 1, wherein the outer ring fixed seal member (7) has a rubber seal lip (21) with a plurality of protrusions (24) spaced apart in the circumferential direction and in sliding contact with the outer periphery of the inner ring (3) via an oil film, and the oil supply gap (23) is a gap formed between adjacent protrusions (24) in the circumferential direction.

3. A rolling bearing as described in claim 2, wherein a cylindrical seal sliding surface (15) is formed on the outer periphery of the inner ring (3), extending axially from the portion where the seal lip (21) slides and connecting to the axial end face (22) of the inner ring (3).

4. A rolling bearing as claimed in claim 3, wherein a cylindrical seal fixing surface (16) is formed on the outer periphery of the inner ring (3) into which the radially inner end of the inner ring fixed seal member (8) is fitted and fixed, and the seal fixing surface (16) and the seal sliding surface (15) are made symmetrical in shape and have the same outer diameter, thereby making the shape of the inner ring (3) symmetrical with respect to a plane perpendicular to the axis.

5. A rolling bearing according to any one of claims 1 to 4, wherein the inner ring fixed seal member (8) is a metallic shield plate that does not come into contact with the inner periphery of the outer ring (2).

6. A rolling bearing as described in any one of claims 1 to 5, wherein the inner ring fixed seal member (8) has a fitting cylindrical portion (26) that fits onto the outer periphery of the inner ring (3), an annular plate portion (27) that rises radially outward from the fitting cylindrical portion (26), and a bent edge portion (28) formed by bending the radial outer end of the annular plate portion (27) axially inward.

7. A rolling bearing as claimed in claim 6, wherein a circumferential groove (12) is formed on the inner circumference of the outer ring (2) at a position corresponding to the inner ring fixed seal member (8) and extending in the circumferential direction, and at least a part of the bent edge portion (28) of the inner ring fixed seal member (8) is accommodated in the circumferential groove (12).

8. A rolling bearing as claimed in claim 7, wherein a seal fixing groove (11) is formed on the inner circumference of the outer ring (2) into which the radially outer end of the outer ring fixed seal member (7) is fitted and fixed, and the cross-sectional shape of the seal fixing groove (11) and the cross-sectional shape of the circumferential groove (12) are made symmetrical, thereby making the shape of the outer ring (2) symmetrical with respect to a plane perpendicular to the axis.

9. A rolling bearing according to any one of claims 1 to 8, wherein grease is sealed in the bearing space (4).

10. A rolling bearing comprising an inner member (51) having a first raceway surface (58), an outer member (52) having a second raceway surface (60), a plurality of rolling elements (53) disposed between the first raceway surface (58) and the second raceway surface (60), and a cage (54) for holding the plurality of rolling elements (53), further comprising a shield (55) protruding from the inner diameter surface of the outer member (52) toward the outer diameter surface of the inner member (51) at a position spaced apart on one axial side with respect to the rolling elements (53) and the cage (54), and a slinger (56) protruding from the outer diameter surface of the inner member (51) toward the inner diameter surface of the outer member (52) at a position spaced apart on the other axial side opposite to the one axial side with respect to the rolling elements (53) and the cage (54), A first oil passage port (70) is formed between the shield (55) and the inner member (51), and a second oil passage port (71) is formed between the slinger (56) and the outer member (52).

11. A rolling bearing as set forth in claim 10, wherein the retainer (54) has an annular portion (64) extending circumferentially on the other axial side relative to the plurality of rolling elements (53), and the slinger (56) has a side plate portion (78) that faces a side surface (68) on the other axial side of the annular portion (64) and is spaced apart in the axial direction.

12. A rolling bearing as claimed in claim 11, wherein the slinger (56) has a tubular plate portion (77) fitted into the inner member (51) so as to face the annular portion (64) with a radial gap therebetween, the side plate portion (78) protrudes radially outward from the other axial side of the tubular plate portion (77), and the radial distance (g1) between the tubular plate portion (77) and the annular portion (64) is smaller than the axial distance (g2) between the side plate portion (78) and a side surface (68) on the other axial side of the annular portion (64).

13. A rolling bearing as claimed in claim 11 or 12, wherein the radial distance (g3) between the outer peripheral edge of the side plate portion (78) and the outer member (52) is set to be larger than the axial distance (g2) between the side surface (68) on the other axial side of the annular portion (64) and the side plate portion (78).

14. A rolling bearing as claimed in claim 13, wherein the outer member (52) has a shoulder portion (61) facing the annular portion (64) with a radial gap therebetween, and a notch portion (63) provided at a position facing the side plate portion (78) in the radial direction and with a larger diameter than the shoulder portion (61), and the outer diameter of the side plate portion (78) is set to a smaller diameter than the shoulder portion (61).

15. A rolling bearing according to any one of claims 10 to 14, wherein the inside diameter of the shield (55) is set to be equal to or smaller than the inside diameter of the cage (54).

16. A rolling bearing according to any one of claims 10 to 15, wherein the retainer (54) is provided at a position farther towards the other axial direction side from the shield (55) than the rolling elements (53).

17. A rolling bearing as claimed in any one of claims 10 to 16, wherein the shield (55) has a tip plate portion (73) which is closest to the inner member (51) within the shield (55), and an inner diameter side tapered plate portion (74) which extends in a direction inclined radially outward from one axial side of the tip plate portion (73).

18. The cage (54) is made of a resin member having an annular portion (64) extending in the circumferential direction and a plurality of pairs of claw portions (65, 66) extending from the annular portion (64) toward one axial side so as to form a space (67) that is open to the radial inside, the radial outside, and one axial side, and the rolling elements (53) are balls arranged in the space (67), 18. The rolling bearing according to claim 10, wherein a space between the claw portions (65, 66) located between the rolling elements (53) adjacent to each other in the circumferential direction is recessed toward the other axial direction side, and wherein a minimum axial thickness from a concave end face (69) located furthest on the other axial direction side between the claw portions (65, 66) to a side face (68) on the other axial direction side of the retainer (54) is defined as a, an axial thickness from a pocket bottom (P) located furthest on the other axial direction side in the space (67) to the side face (68) on the other axial direction side of the retainer (54) is defined as b, and a minimum distance between an imaginary plane passing through centers (O) of the multiple rolling elements (53) and the concave end face (69) is defined as c, such that a > b and c > 0 are satisfied.

19. A rotary machine comprising a rolling bearing (50) according to any one of claims 10 to 18, a rotating part (101) supported by the rolling bearing (50), and an oil supply part (102) that supplies oil to one axial side of the rolling bearing (50).

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