Ball bearing with seal and bearing device

Abstract

To prevent an entry of foreign substance into a bearing inner space of a ball bearing and suppress a deformation of a holder.SOLUTION: A holder 10 is a crown-shaped holder containing an engineer plastic, in which a dimensional relation of a diameter φx of a ball 5, a radius Ry of a radial inner peripheral face D of a pocket 11 passing through a pocket center C of the pocket 11 and in a cross section including an axial core O of a bearing, and a radius Rz of a circumferential inner peripheral face E of the pocket 11 in a cross section perpendicular to a bearing radial straight line passing through the pocket center C at the pocket center C is φx<2Ry<2Rz. In a ball bearing, the circumferential inner peripheral face E includes a first inner peripheral face E1 on a base part 12 side and a second inner peripheral face E2 on a tip end side. A center C2 of the second inner peripheral face E2 is decentered from a center C1 of the first inner peripheral face E1 toward the base part 12 side.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a sealed ball bearing and a bearing device. [Background technology]

[0002] For example, in various vehicles such as automobiles and construction machines, and various industrial machines, A large number of bearings are used on the motor shaft of a transmission (speed increase / decrease gear) equipped with a motor. The bearings used in these devices are different from the bearings used to support shafts in general devices. These machines are generally used under high speed conditions. The lubricating oils used in these machines contain Foreign matter such as wear powder from gears is mixed in. Therefore, by providing a seal member at the end of the bearing, By preventing foreign matter from entering the bearing, the bearing life is reduced and lubricating oil penetration is prevented. By controlling the amount of mixing, the stirring resistance is reduced.

[0003] For example, in Patent Document 1, a seal lip provided on a seal member is provided with a protrusion, and a shaft By creating an oil passage that connects the inside of the receiver with the outside, the seal lip and the seal sliding surface This keeps the bearing life from being reduced by gear wear debris. At the same time, fluid lubrication of the seal area is achieved to reduce seal torque.

[0004] Patent Document 2 also describes a crown-shaped retainer having a circular base and a column protruding from the base. The thickness of the crown-shaped cage in the radial direction gradually decreases from the base to the tip of the column. The radial gap between the outer peripheral surface of the base and the inner peripheral surface of the shoulder of the outer ring is The technology is to make the radial gap larger than the gap between the inner peripheral surface of the inner ring and the outer peripheral surface of the shoulder of the inner ring. It has been disclosed.

[0005] According to Patent Document 2, even if the lubricant is scattered by centrifugal force during high-speed rotation, it is dispersed to the outside of the base. The lubricant is stored between the outer ring's outer surface and the inner surface of the shoulder of the outer ring, preventing the lubricant from reaching the raceway surface of the outer ring. This reduces the stirring resistance, making it possible to reduce torque and heat generation. It is also said to be able to suppress deformation of the cage due to centrifugal force during high-speed rotation. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2016 / 143786 [Patent Document 2] Patent Publication No. 2021-195973 Summary of the Invention [Problem to be solved by the invention]

[0007] In Patent Document 1, it is possible to suppress the reduction in bearing life. Bearings used under high speed conditions, such as supporting motor shafts, are subject to harsh conditions that exceed expectations. Under certain operating conditions, there is a risk of the bearing rings overheating due to interference with the cage, or the cage being damaged.

[0008] In addition, in Patent Document 2, measures are taken to prevent damage to the cage under high-speed conditions, but this bearing Although the bearing is provided with seal members at both axial ends, the seal members are non-contact seals. Because it is a seal, it is not possible to prevent the intrusion of foreign matter large enough to affect the bearing life. Therefore, when this bearing is used in devices such as transmissions and speed reducers, There is concern that foreign matter may get inside the bearing, shortening the bearing life. Devices that integrate inverters and gears (transmissions, etc.) are becoming increasingly popular. The main type of lubrication is oil, and the bearings that support the motor shaft of the drive motor are the same as those in the transmission. This makes it possible to more reliably prevent foreign matter from entering the bearing. There is a request to do so.

[0009] Therefore, the object of the present invention is to prevent the intrusion of foreign matter into the bearing internal space while maintaining the bearing internal space under high speed conditions. The purpose is to suppress deformation of the cage. [Means for solving the problem]

[0010] In order to solve the above problems, the present invention provides an inner ring and an outer ring, a cage having balls arranged therebetween and pockets for holding the balls in a circumferential direction; a seal member that closes the opening at the axial end of the bearing internal space formed between the inner ring and the outer ring; Preparation, dmn={(D+d) / 2}×n D: Bearing outer diameter (mm) d: bearing inner diameter (mm) n: rotation speed (min -1 ) For ball bearings used in environments where the dmn value specified in is 700,000 or more, The seal member is fixed to one of the inner ring and the outer ring and is set to the other. The seal lip is provided with a plurality of seal lips arranged in the circumferential direction. The plurality of protrusions have gaps between adjacent protrusions in the circumferential direction, Furthermore, as the bearing rotates, the seal is pulled into the gap between the projection and the seal sliding surface. The seal lip and the seal sliding surface are kept in a fluid lubricated state by an oil film of lubricating oil. and The cage includes an annular base and a plurality of pillars protruding in one direction from the base. The cage is a crown type cage made of engineering plastic, and the diameter of the balls is φx, the diameter of the pockets is The radius of the radially inner peripheral surface of the pocket in a cross section that passes through the center of the pocket and includes the axis of the bearing Ry, in a cross section perpendicular to a bearing radial line passing through the center of the pocket at the center of the pocket the dimensional relationship of the radius Rz of the inner peripheral surface of the pocket in the circumferential direction is φx<2Ry<2Rz, The circumferential inner surface has a first inner surface on the base side and a distal end of the column portion from the first inner surface. a second inner circumferential surface on the end side, the center of the second inner circumferential surface being closer to the center of the first inner circumferential surface; A sealed ball bearing that is eccentric toward the base side is used (Configuration 1).

[0011] In the first aspect, the radius Rz of the circumferentially inner peripheral surface is a radius Rz1 of the first inner peripheral surface. A configuration can be adopted in which the radius Rz2 of the second inner circumferential surface is set equal to the radius Rz1 of the first inner circumferential surface (Configuration 2).

[0012] In the first aspect, a recess is provided between the first inner circumferential surface and the second inner circumferential surface as an oil reservoir. can be adopted (Configuration 3).

[0013] In addition, in the configuration 1, the seal lip is made of nitrile rubber, acrylic rubber, or fluororubber. A configuration using a single or multiple materials selected from the above materials can be adopted (Configuration 4).

[0014] Furthermore, in the configuration 1, the lubricant is supplied to the bearing internal space from one axial end side to the other axial end side. In the case where the direction is one-way to the other end side, the sealing member is provided only at the opening on one axial end side. A configuration can be adopted (Configuration 5).

[0015] In addition, a plurality of elements selected from the above-mentioned configurations 2 to 5 are added to configuration 1. In other words, as elements to be added to configuration 1, configurations 2 and 3, and configurations 2 and 4 can be added. , configuration 2 and 5, configuration 2, 3 and 4, configuration 2, 3 and 5, configuration 2, 4 and 5, configuration 2, 3, 4 and 5 etc.

[0016] The sealed ball bearings according to these embodiments are used in drive motors and reducers for electric transport equipment. Alternatively, a bearing device can be employed in which the rotating shaft of a speed increaser is supported by the sealed ball bearing. [Effects of the Invention]

[0017] The present invention provides a seal portion capable of maintaining a fluid lubrication state between a seal lip and a seal sliding surface. By adopting this material, we aim to reduce seal torque and improve the flow of lubricant into the bearing interior space. This reduces the agitation resistance of the lubricant inside the bearing. This allows the bearing to be used in high speed rotation ranges with a dmn value of 700,000 or more. Furthermore, it is possible to prevent the intrusion of foreign matter of a size that could affect the bearing life.

[0018] In addition, engineering plastic is used as the material for the crown cage, and the ball diameter of the ball bearing is φx, Dimensional relationship between the radius Ry of the radial inner peripheral surface of the cage pocket and the radius Rz of the circumferential inner peripheral surface and further, a second inner surface of the pocket in the circumferential direction that is farther from the base. The center of the circumferential surface is offset toward the base side from the center of the first inner circumferential surface on the base side, This suppresses deformation of the cage and prevents foreign matter from getting caught between the cage and the seal member. . [Brief explanation of the drawings]

[0019] [Figure 1]FIG. 1 is a vertical cross-sectional view showing an embodiment of the present invention. [Figure 2] Enlarged view of the main part of Figure 1 [Figure 3] Vertical cross-sectional view showing the main parts of the cage [Figure 4] A cross-sectional view showing the main part of the cage, perpendicular to the bearing radial direction (cross-sectional view taken along line IV-IV in Figure 3) [Figure 5] Schematic diagram showing the relationship between the cage and balls [Figure 6] Enlarged view of the main area near the seal ship [Figure 7A] Right side view of Figure 6 [Figure 7B] Enlarged view of the main part of Figure 7A [Figure 8] Vertical cross-sectional view showing a modified example DETAILED DESCRIPTION OF THE INVENTION

[0020] An embodiment of the present invention will be described with reference to the drawings. The rolling bearing 1 is provided with a seal member 20 at the opening at the end of the bearing.

[0021] As shown in FIGS. 1 to 3, the rolling bearing 1 includes an inner ring 3 and an outer ring 4. and a pocket 11 that holds the rolling elements 5 in the circumferential direction. The rolling elements 5 are balls (steel balls), so Hereinafter, this will be referred to as ball 5. Also, this rolling bearing 1 will be referred to as sealed ball bearing 1 or The direction along the bearing center axis of the bearing 1 is referred to as the "bearing axial direction" or simply as the bearing 1. The direction perpendicular to the axial direction is called the "bearing radial direction" or simply the "radial direction." The circumferential direction around the bearing central axis is referred to as the "bearing circumferential direction" or simply as the "circumferential direction."

[0022] The cage 10 is a crown-shaped cage molded from engineering plastic. , a base portion 12 having an annular shape, and a plurality of pillar portions 13 projecting from the base portion 12 in the axial direction. A pair of pillars 13, 13 arranged in parallel along the circumferential direction are arranged in the same position along the circumferential direction. The space between the pair of pillars 13 is a concave shape. The outer diameter surface of the cage 10 is a curved surface (cylindrical surface) without any steps. The outer diameter surface and the inner diameter surface of the cage 10 communicate with each other at the pocket 11 portion.

[0023] The tip of the column 13 is a holding claw 14. The holding claws 14, 1 on both sides of the pocket 11 are The pockets 11 and 4 are curved in a direction that brings them closer to each other. Adjacent columns 13, 13 may be connected to each other between the pockets 11. The balls 5 held by the pocket 11 are held in the pocket 11 and are pressed against the raceway surface 3 of the inner ring 3. a and the raceway surface 4 a of the outer ring 4 .

[0024] The inner ring 3 has a rotating shaft (not shown) fixed to its inner diameter portion 3b, and is circumferentially rotated together with the rotating shaft. The outer ring 4 is a housing, gear, and other components (not shown) that rotate from the rotating shaft. The bearing 1 is attached to a fixed member that bears the load. The rotating shaft is supported so as to be rotatable. The rotating shaft of the drive motor of the electric transport equipment, or the reduction gear of the electric transport equipment The bearing center axis of the bearing 1 and the rotation center axis of the rotating shaft are are set on the same axis.

[0025] When the bearing 1 is assembled, an appropriate lubricant such as grease is filled into the bearing internal space A. In addition, when in use, the bearing internal space A is Lubricant (lubricating oil) is supplied from the outside through the opening on one end side. The lubricant (lubricating oil) flows out of the bearing internal space A from the opening on the other axial end side of the bearing internal space A. Bearing 1 is basically used under oil lubrication, and after initial lubrication The grease sealed in is then replaced by lubricating oil supplied from outside the bearing. When grease is sealed in for lubrication, it should be 5 to 20% of the total space volume within the bearing internal space A. It is desirable to seal the grease in %.

[0026] The lubricating oil that lubricates the drive motor, transmission, and other equipment contains gear wear particles and clutch wear particles. There may be foreign matter such as powder and other substances depending on the equipment in which the bearing 1 is installed. It is desirable that the oil is not floating in the oil but is captured somewhere. The bearings are lubricated with the same lubricating oil as the drive motor, transmission, and other equipment. A seal member 20 is attached to the opening at the axial end of the space A. In this embodiment, The bearing has seal members 20 at both axial ends of the bearing internal space A.

[0027] The seal member 20 is an annular member that covers the opening at the axial end of the bearing internal space A. The seal member 20 separates the bearing internal space A from the outside. Since foreign matter exists in the lubricating oil on the outside of the bearing across the seal member 20, 0 prevents these foreign objects from entering the bearing interior space A from outside the bearing.

[0028] As shown in FIG. 2, the seal member 20 comprises a metal core 23 and a seal member 24 fixed integrally with the core 23. The core metal 23 has an L-shaped cross section around the entire circumferential direction. In this embodiment, the core metal 23 is a pressed product. The elastic portion 24 is made of rubber and is vulcanization bonded to the core metal 23. The vulcanization bonding is performed by, for example, This can be done by placing the core metal 23 in a mold and vulcanizing the vulcanized rubber material.

[0029] The elastic portion 24 of the seal member 20 has a fitting portion 25 that protrudes radially outward on the outer diameter side. , a main body 26 covering the core metal 23, a protruding portion 22 protruding from the main body 26 toward the inner diameter side, and a protruding portion 22 The outer ring 4 has a seal lip 21 that projects inward in the radial direction like a tongue at the tip of the seal lip 21. A seal groove 8 is formed around the entire inner periphery of the axial end of the seal member 20. The fitting portion 25 is fitted into the seal groove 8 to be fixed to the outer ring 4 .

[0030] A seal sliding surface B that slides circumferentially against the seal lip 21 is formed on the outer periphery of the inner ring 3. The seal sliding surface B is a cylindrical surface extending over the entire circumference.

[0031] As shown in FIG. 6, the seal lip 21 has a circular ring shape that is continuous in the radial direction and has a constant width in the axial direction. and a head portion formed in a protruding piece shape that bends outward from the waist portion. An interference is set between the head of the seal lip 21 and the seal sliding surface B. When the member 20 is installed in the predetermined orientation shown in FIGS. 1 and 2, the sealing lip 21 The deformation of the rubber-like elasticity is caused by the seal sliding surface B being pressed against the seal sliding surface B and bending outward in the axial direction. This generates tension on the seal lip 21. , are absorbed by the change in the degree of deflection of the seal lip 21.

[0032] As shown in FIG. 7A, the seal lip 21 has a plurality of protrusions 27 arranged in parallel along the circumferential direction. The protrusion 27 extends in a direction perpendicular to the circumferential direction over its entire length, and extends over the entire circumferential direction. Therefore, the gap formed between the adjacent protrusions 27 in the circumferential direction is The gaps 28 are also formed at uniform intervals around the entire circumference. Between the lip 21 and the seal sliding surface B, an oil passage is formed that connects the bearing internal space A with the outside of the bearing. It is completed.

[0033] As shown in FIG. 7B, the protrusions 27 are arranged on both sides of the circumferential width from the center of the circumferential width. The circumferential end portion 29 is formed so that the gap between the seal sliding surface B and the circumferential end portion 29 becomes wider as it approaches the circumferential end portion 29. That is, the projection 27 is larger on the side of the gap 28 between the seal sliding surface B and the projection 27 at the center p A wedge-shaped gap is formed that is smaller on the side closer to the center.

[0034] As shown in FIG. 6, the protrusion 27 is located approximately at the seal sliding position on an imaginary plane including the bearing center axis. This area extends along the seal sliding surface B (the left side in Fig. 6). Therefore, the protrusion 27 that occurs when the bearing rotates is The sliding portion of the seal sliding surface B, that is, the projection 27, guides the lubricating oil in the gap 28 between the projection 27 and the seal. The wedge effect occurs when the bearing is pulled in the circumferential direction toward the wedge-shaped gap between the bearing and sliding surface B. The oil film is formed between the projection 27 and the seal sliding surface B. The area is defined as the area where a predetermined amount of effective friction is applied in the direction (axial direction) along the seal sliding surface B on the aforementioned virtual plane. The sliding portion between the projection 27 and the seal sliding surface B is Hertz's elastic contact. It is thought that the contact ellipse is generated based on the contact theory, and the major axis of the contact ellipse is the same as that of the contact ellipse mentioned above. This corresponds to the limit length.

[0035] When the peripheral speed of the relative rotation between the seal lip 21 and the seal sliding surface B is less than a certain value, microscopically, The bearing rotates faster and the protrusions When the peripheral speed of the relative rotation between the protrusion 27 and the seal sliding surface B exceeds a certain value, the protrusion 27 and the seal sliding surface B The oil film thickness between the projections 27 and the seal sliding surface B is much greater than the composite roughness σ between the projections 27 and the seal sliding surface B. and seal sliding surface B are completely separated by an oil film, creating a hydrodynamic lubrication state. The oil film between the seal lip 21 and the seal sliding surface B is completely separated, creating a fluid lubrication state. In this state of fluid lubrication, the sealing torque of the seal member 20 can be controlled in a non-contact manner. This reduces the temperature rise of the sealed bearing to the same level as that of the seal lip 2. The adsorption action of 1 can be prevented.

[0036] Here, if the oil film parameter Λ≧3, the lubrication mode of the sliding part is considered to be in a hydrodynamic lubrication state. The oil film parameter Λ is the ratio of the composite roughness σ to the minimum oil film thickness h0 at the sliding part. and Λ=h0 / σ. The minimum oil film thickness h0 is calculated based on the elastohydrodynamic lubrication theory. The composite roughness σ=√(Rq1 2 +Rq2 2 ) Rq1 is the seal that forms the sliding part mentioned above. Rq2 is the root mean square roughness of the sliding surface B of the projection 27. The root mean square roughness is defined as the root mean square roughness as specified in JIS (B0601:2013). The root mean square roughness Rq value (μm) is

[0037] The oil film parameter Λ depends on the composite roughness σ, and the smaller the composite roughness σ, the thicker the oil film. The sliding portion between the projection 27 and the seal sliding surface B is lubricated with fluid even when the peripheral speed is extremely low. In order to achieve this state, it is preferable that the composite roughness σ of the sliding portion is 0.9 μm or less. For example, if the composite roughness σ is 0.9 μm, the lubricant is transmission oil (30 cst, 40°C), and the ambient temperature is Under the calculation conditions of ambient temperature 20°C and peripheral speed 0.2 m / s, the Johnson chart The oil lubrication mode was determined, and the minimum oil film thickness h0 was 2.8 μm and the oil film parameter Λ was 3 or more, the lubrication mode became EI mode. If the composite roughness σ of surface B is 0.9 μm or less, fluid lubrication is ensured in the actual operating range of the bearing. It is expected to become a state.

[0038] For example, applications that support rotating parts in vehicle transmissions typically involve splashing. The transmission oil is supplied to the sealed bearing as lubricating oil by an appropriate method such as an oil bath. The lubricating oil is circulated by an oil pump, and an oil filter installed in the circulation path Large foreign particles with a particle size of more than 0.05 mm enter the bearing internal space A. If the protrusion 27 is inserted, it is considered that it will have an adverse effect on the bearing life. ) is set to 0.07 mm or less, a gap 2 that cannot easily pass through such large foreign objects can be created. In order to improve the oil permeability of the gap 28, the protrusions 27 It is desirable to set the protrusion height h to 0.05 mm or more.

[0039] When the protrusion height h of the protrusions 27 is 0.07 mm or less, for example, the protrusions 27 adjacent to each other in the circumferential direction The distance between the projections is 0.3 mm or more and 2.6 mm or less, and the circumferential width of the projections 27 is 0.2 mm or more. 0 mm or less, and the curvature radius of the surface of the protrusion 27 is in the range of 0.15 mm or more and less than 2.0 mm In this example, the oil temperature can be set to 30 to 120°C, and the seal lip 21 and seal When the relative peripheral speed of the sliding surface B of the roller is 0.2 m / s or more, the Greenwood -Based on the viscous parameter gv and the elastic parameter ge, which are dimensionless numbers determined by Johnson In the lubrication region diagram (Johnson chart) based on the above, the constant viscosity - rigid body region (RI mode) or in the isoviscosity-elastic region (EI mode, soft EHL) lubrication mode, i.e. In other words, it is considered that the above-mentioned fluid lubrication state is achieved. When the gap between the projections is 2.6 mm, the distance between the projections 27 and the seal sliding surface B is calculated to be approximately 3 μm. An oil film is formed at a distance of 2.6 mm, and the oil film tends to become thicker when the distance is less than 2.6 mm. When the gap is 2.6 mm or less, the bearing rotation torque tends to decrease (i.e., the seal torque tends to decrease). If the aforementioned interval is less than 0.3 mm, the transfer surface for forming the protrusion 27 may be It becomes difficult to form it into a mold by milling.

[0040] As described above, by creating a fluid lubrication state between the seal lip 21 and the seal sliding surface B, The friction (seal torque) caused by the friction between the seal lip 21 and the seal sliding surface B is substantially The wear of the seal lip 21 is substantially zero, and the seal lip 21 and the seal sliding It is possible to suppress heat generation due to sliding between the seal lip 21 and the seal surface B. The relative rotational speed allowed between surface B is higher, so operation under higher speed conditions is possible. It becomes possible.

[0041] The seal lip 21 may be made of, for example, nitrile rubber, acrylic rubber, or fluororesin. A single or multiple materials selected from the group consisting of natural rubber can be used. It may be used only for the seal lip 21 or for the entire elastic portion 24 including the seal lip 21. It's fine.

[0042] The pocket 11 of the cage 10 corresponds to the ball 5 having a diameter of φx. As shown in FIG. 3, the inner surface of 11 is an inner surface (spherical surface) that draws an arc along the radial direction of the bearing. The radius in the bearing radial direction is set to Ry. 2Ry is twice Ry. and corresponds to the diameter of the inner surface of the pocket 11 in the radial direction of the bearing. If the center of the pocket 11 is the pocket center C, then the The inner peripheral surface D (hereinafter referred to as the radial cross section) of the pocket 11 in a cross section including the axis O (hereinafter referred to as the radial cross section) , referred to as the radial inner peripheral surface D) has a radius of Ry and a diameter of 2Ry (hereinafter referred to as the radial pocket diameter 2R The center of the pocket C and the center of the ball 5 are aligned by design. The center of the arc of the inner peripheral surface D is indicated by symbol C' in FIG. 3, and the center of the arc of the inner peripheral surface D is indicated by symbol C' in FIG. In FIG. 3, the radially inner peripheral surface D is eccentric to the D side at the bottom F of the pocket 11. The bearing center line is shown in Figure 3 as a continuous line extending from the outer diameter end d2 to the inner diameter end d1. This shows one cross section through which the pocket passes, but the radial pocket diameter 2Ry is not limited to this cross section. The cross section is set at any cross section including the bearing radial line connecting the center C of the bearing and the axis O of the bearing ( However, if a recess H such as an oil reservoir is provided on the inner surface of the pocket 11, the recess H (Except for locations in

[0043] As shown in FIG. 4, the inner surface of the pocket 11 is formed in a circular arc along the circumferential direction of the bearing. The inner surface is spherical, and the radius of the bearing circumferential direction is set to Rz. That is, the cross section (hereinafter referred to as the circumferential section) that is perpendicular to the radial line of the bearing passing through the pocket center C The inner peripheral surface E of the pocket 11 in the circumferential cross section (hereinafter referred to as the circumferential inner peripheral surface E) The radius of the pocket is Rz and the diameter is 2Rz (hereinafter referred to as the circumferential pocket diameter 2Rz). The inner peripheral surface E in the circumferential direction extends from the tip G of the holding claw 14 through the bottom F of the pocket 11 in the opposite direction. 4 shows the line passing through the pocket center C and continuing to the tip G of the holding claw 14 on the side. The figure shows a cross section perpendicular to the bearing radial line connecting the socket center C and the bearing axis O. This circumferential pocket diameter 2Rz is not only on this cross section, but also passes through the pocket center C and It is set at any cross section that intersects with the bearing radial line that passes through the center C of the ball (however, If a recess H for an oil reservoir or the like is provided on the inner surface of the socket 11, the area other than the recess H Ku).

[0044] In Figures 3 and 4, the difference in diameter (radius) of each arc and the positional relationship of the arc centers are is depicted in an exaggerated manner.

[0045] Here, the diameter φx of the ball 5, the radial pocket diameter 2Ry on the inner surface of the pocket 11, and the circumferential The dimensional relationship with the opposite pocket diameter 2Rz is φx<2Ry<2Rz It is set to be.

[0046] In this regard, the diameter φx of the ball 5 is smaller than the radial pocket diameter 2Ry of the pocket 11 (see Fig. 3) and circumferential pocket diameter 2Rz (see Figure 4) are not large, Since the balls 5 are tightly held, it does not function as a cage 10. Therefore, φx<2 The requirements of Ry and φx<2Rz are required.

[0047] Furthermore, the circumferential pocket diameter is larger than the radial pocket diameter 2Ry of the pocket 11 (see FIG. 3). By setting 2Rz (see Figure 4) large, the ball 5 will move forward and backward during high-speed rotation. The balls 5 are then held in place by the retainer 10. This causes interference between the retainer 10 and the surrounding components (such as the inner ring 3 and outer ring 4). As it rotates in the circumferential direction, it is pulled by the cage 10 due to the speed difference in the circumferential direction. This makes it easier to avoid interference due to deformation occurring in the cage 10. This is because 2Ry<2Rz is set. By setting the ball 5 and the radial inner peripheral surface D of the pocket 11, a first gap w1 (see FIG. 3) In addition, the second gap w2 (see FIG. 4) between the ball 5 and the circumferential inner surface E of the pocket 11 is secured large. This is the effect of doing so.

[0048] In the cross section of FIG. 3, the radially inner peripheral surface D represents a circular arc with a diameter of 2Ry, and the symbol d1 represents the inner diameter The reference symbol d1 indicates the outer diameter side end d2. The inner peripheral surface E in the direction of the arrow indicates a circular arc having a diameter of 2Rz, and the symbol F indicates its bottom F. G indicates the tip G of the holding claw 14.

[0049] On the other hand, if 2Ry of the pocket 11 is too large, the radial play between the balls 5 and the cage 10 becomes large. This increases the likelihood of interference between the cage 10 and surrounding components (such as the inner ring 3 and outer ring 4). At high speeds, the influence of centrifugal force deformation is also combined, making the above interference more likely to occur. For this reason, it is not desirable to make 2Ry too large. Therefore, the requirement of 2Ry<2Rz is However, in order to suppress such interference, As a condition for this, the cage 10 is made of engineering plastic. This is a requirement.

[0050] As shown in FIG. 4, the circumferential inner surface E is a first inner surface E1 on the base portion 12 side and a holding claw 14 side, i.e., a second inner circumferential surface E2 located closer to the tip end of the column portion 13 than the first inner circumferential surface E1, The center C2 of the arc of the second inner circumferential surface E2 is closer to the base portion 12 than the center C1 of the arc of the first inner circumferential surface E1. This allows the balls 5 and the pockets 11 to be eccentrically positioned in the circumferential direction while maintaining the ball 5 holding function. Therefore, the second gap w2 between the inner peripheral surface E and the outer peripheral surface E can be increased.

[0051] In FIG. 4, the center C1 of the arc of the first inner circumferential surface E1 and the second inner circumferential surface The line connecting the center C2 of the arc of E2 is parallel to the axial direction of the bearing. is the midpoint between the center C1 of the arc of the first inner circumferential surface E1 and the center C2 of the arc of the second inner circumferential surface E2. Furthermore, it is desirable that the center C1 of the arc of the first inner peripheral surface E1 and the center C2 of the arc of the second inner peripheral surface E2 are The distance w from the center C2 is set appropriately depending on the diameter φx of the ball 5 and the specifications of the bearing. For example, , which can be set to a value between 0.1 and 0.2 mm.

[0052] However, one of the disadvantages of making the circumferential pocket diameter 2Rz too large is that the cage The main problem is that the axial play of the cage 10 becomes large. In this case, there is a concern that the seal member 20 may interfere with the seal member 20 depending on the conditions of use. Therefore, the clearance in the axial direction between the seal member 20 and the cage 10 is determined by the above-mentioned axial play and Taking into consideration deformation of the cage 10 due to centrifugal force, it is desirable to secure a gap of 0.1 mm or more. .

[0053] According to the above configuration, dmn={(D+d) / 2}×n D: Bearing outer diameter (mm) d: bearing inner diameter (mm) n: rotation speed (min -1 ) Under high-speed conditions where the dmn value specified in is 700,000 or more at its maximum rotation speed At the same time, it is possible to prevent the intrusion of foreign matter of a size that could affect the bearing life. Furthermore, deformation of the cage 10 during high-speed operation is suppressed, and the cage 10 and the seal It is also possible to prevent foreign matter from getting caught between the member 20.

[0054] Regarding the radius Rz of the inner peripheral surface E in the circumferential direction, the radius Rz1 of the first inner peripheral surface E1 and the radius Rz2 of the second inner peripheral surface E2 are It is desirable that the radius Rz2 of the peripheral surface E2 is set to the same value. As long as there is no problem in maintaining the holding function and ensuring the second gap w2, for example, as shown in FIG. The radius Rz1 of the first inner circumferential surface E1 and the radius Rz2 of the second inner circumferential surface E2 may be different values. In this case, the radius Rz1 of the first inner peripheral surface E1 is larger than the radius Rz2 of the second inner peripheral surface E2. The radius Rz1 of the first inner circumferential surface E1 may be set to a numerical value, or the radius Rz1 of the second inner circumferential surface E2 may be set to a numerical value. It may be set to a value smaller than z2.

[0055] In FIG. 5, the recess H for oil collection formed on the inner surface of the pocket 11 is omitted. Here, the theoretical connection point between the first inner peripheral surface E1 and the second inner peripheral surface E2 passes through the pocket center C. The theoretical intersection point is indicated by the symbol J in Figure 5. When the theoretical intersection point J is viewed macroscopically, it is a point that directly connects the first inner peripheral surface E1 and the second inner peripheral surface E2. Therefore, the curvature is discontinuous near the theoretical intersection point J. The curvature should be as continuous as possible so that there are no bends or other connecting points. In this case, for example, as shown in FIG. If a recessed portion H is provided between the second inner peripheral surface E2 and the recessed portion H as an oil reservoir, the theoretical intersection point J is The problem of the bending point between the first inner peripheral surface E1 and the second inner peripheral surface E2 can be solved by positioning the bending point within the first inner peripheral surface E1.

[0056] In the above embodiment, the lubricant (lubricating oil) is supplied to the bearing internal space A from one axial end side and Since the pressure is applied from both the axial end and the other end, the seal members 20 are provided at the openings at both axial ends. The contents of the present invention have been explained using the structure of the double-sided seal as an example. The lubricant (lubricating oil) is supplied to the internal space A in one direction from one axial end to the other axial end. In this case, a one-side seal configuration is adopted in which the seal member 20 is provided only at the opening on one axial end side. In other words, in the case of a one-sided seal, the opening on the side where the lubricant (lubricating oil) is supplied In the case of one-side sealing, the retainer 10 is preferably The bearing 10 is inserted into the bearing internal space A from the opposite side where the seal member 20 is not provided. desirable.

[0057] As mentioned above, the dmn value at the maximum rotation speed is 700,000 or more under high-speed conditions. For bearings 1 used under these conditions, a crown cage made of engineering plastic is used. Therefore, it is necessary to suppress deformation of the cage 10 due to high-speed rotation. When a crown-shaped cage made of a material is applied, for example, the flow of lubricant (lubricating oil) into the bearing internal space A is If the input is too large, there is a concern that the bearing life may be shortened. There is also a risk that foreign matter such as gear wear particles may enter the bearing internal space A, shortening the bearing life. Therefore, in the present invention, the contact portion of the seal lip 21 can be maintained in a fluid lubricated state. By adopting a seal member 20 that can be used, it is possible to prevent the intrusion of foreign matter that can affect the bearing life. It is possible to control the amount of lubricant (lubricating oil) flowing in. That is, it is possible to control the amount of lubricant (lubricating oil) flowing in. The contact portion between the resin crown cage having the seal lip 21 and the seal member 22 can be kept in a fluid lubricated state. The synergistic effect of the seal member 20 has made it possible to extend the bearing life more than ever before.

[0058] Table 1 below shows the results of sudden acceleration and deceleration tests based on the amount of internal oil in a resin crown cage. The results are shown below.

[0059] [Table 1]

[0060] From the above results, it can be seen that the less the amount of lubricant (lubricating oil) that flows into the bearing internal space A, the better the bearing The lifespan is longer. This is because the less lubricant (lubricating oil) flows in, the less stirring resistance there is. As mentioned above, the contact portion of the seal lip 21 is The seal member 20 that can be maintained in a lubricated state is, for example, a seal that is fluid lubricated and has an effect on the bearing life. It is possible to prevent the intrusion of foreign matter of 0.050 mm or more. Although the material 20 is a contact seal, it is fluid lubricated during operation, so the lubricant (lubricating oil) There is no need to secure an inflow volume more than necessary, and as in Tests No. 3 and No. 4 in Table 1 above, Therefore, there is no problem even if excessive lubricant (lubricating oil) is prevented from entering the bearing internal space A. You can see that.

[0061] In the above embodiment, the cage 10 is made of engineering plastic. The material may contain at least an engineering plastic.

[0062] In the above embodiment, the rotating shaft is a drive motor provided in an electric transport device such as an electric vehicle. Take the rotating shaft of a motorized transport device, or the rotating shaft of a reducer or speed increaser, as an example. However, this phenomenon has also been used in the support parts of rotating shafts in various transport equipment, industrial machinery, etc. The present invention can be applied to various types of transportation equipment. Shafts, constant velocity joints, propeller shafts, turbochargers, transformers in power transmission paths Support for rotating parts of transmissions, wheel bearings, or rotating shafts of various machine tools, generators, etc. It can also be applied to the

[0063] In the above embodiment, the sealed ball bearing 1 has a seal lip of the seal member 20. The configuration of this invention has been explained using an example in which 21 is arranged on the inner ring 3 side. For example, as shown in FIG. 8, a configuration is adopted in which the seal lip 21 is disposed on the outer ring 4 side. Good too.

[0064] In the above embodiment, the elastic portion 24 of the seal member 20 is made of rubber. The rubber is vulcanized and bonded to the core wire 23, but the rubber may be bonded to the core wire by a method other than vulcanization. 23. Also, if the strength and durability of the seal member 20 are ensured, The seal member 20 may be formed only of the elastic portion 24 without using the core metal 23. The elastic portion 24 may be made of a material other than rubber, such as synthetic resin.

[0065] The embodiments disclosed herein are illustrative in all respects and are not to be considered as limiting. The scope of the invention is indicated by the appended claims rather than by the foregoing description. It is intended to include all modifications within the meaning and scope of the claims. do. [Explanation of symbols]

[0066] 1. Bearing (sealed ball bearing) 3. Inner circle 4 outer ring 5 balls (rolling elements) 10 Cage 11 pockets 12 base 13 Pillar section 20 Sealing material 21 Sealing lip 27 Protrusion 28 Gap A Bearing internal space B Seal sliding surface C Pocket Center D Radial inner surface E Circumferential inner surface E1 1st inner surface E2 2nd inner surface

Claims

1. A ball bearing comprising an inner ring (3), an outer ring (4), balls (5) disposed between the inner ring (3) and the outer ring (4), and a cage (10) having pockets (11) for holding the balls (5) along a circumferential direction, The cage (10) is a crown-shaped cage that includes an annular base (12) and a plurality of pillars (13) that protrude in one direction from the base (12), and that includes an engineering plastic, and the dimensional relationship between a diameter φx of the balls (5), a radius Ry of a radial inner peripheral surface (D) of the pocket (11) in a cross section that passes through a pocket center (C) of the pocket (11) and includes an axis (O) of the bearing, and a radius Rz of a circumferential inner peripheral surface (E) of the pocket (11) in a cross section that passes through the pocket center (C) and is perpendicular to a radial line of the bearing at the pocket center (C), is φx<2Ry<2Rz, The circumferential inner surface (E) comprises a first inner surface (E1) on the base (12) side and a second inner surface (E2) that is closer to the tip of the column portion (13) than the first inner surface (E1), and the center (C2) of the second inner surface (E2) is eccentric toward the base (12) side relative to the center (C1) of the first inner surface (E1), and the center (C') of the radial inner surface (D) is set at a point of radius Ry from the bottom (F) of the pocket (11), which is the intersection of the circumferential inner surface (E) and the radial inner surface (D), toward the pocket center (C).

2. The ball bearing according to claim 1, wherein the radius Rz of the circumferential inner surface (E) is set so that the radius Rz1 of the first inner surface (E1) and the radius Rz2 of the second inner surface (E2) are equal.

3. 2. The ball bearing according to claim 1, wherein a recess (H) is provided as an oil reservoir between the first inner peripheral surface (E1) and the second inner peripheral surface (E2).

4. A bearing device using the ball bearing according to any one of claims 1 to 3, in which a rotating shaft of a drive motor, a reducer, or a speed increaser for an electric transport device is supported by the ball bearing.

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