Rolling bearings

Abstract

To provide a rolling bearing that can stabilize sealing performance. [Solution] The rolling bearing comprises an inner ring 2, an outer ring, a plurality of rolling elements interposed between the inner ring 2 and the outer ring, and a sealing member 6 that closes the bearing space between the inner ring 2 and the outer ring. The sealing member 6 includes a core metal 10 and a contact-type main lip 15 located radially inward from the core metal 10. The main lip 15 has a contact portion 15c that contacts the seal groove 7 of the inner ring 2 with an overlap. The sealing member 6 is equipped with a radial change amount reduction means Rcr that reduces the radial change amount of the contact portion 15c to a predetermined value or less within the range of the overlap. The radial change amount reduction means Rcr ensures that, at the maximum overlap, the maximum axially outward protruding position Pk of the bent portion Be is axially outward from the bottom Ks of the axially outward portion of the constricted portion 14, and is the same as or axially inward from the axial position Tm of the end face of the inner ring 2 or the outer ring.

Description

Technical Field

[0001] The present invention relates to a rolling bearing and a technique capable of stabilizing the sealing performance.

Background Art

[0002] In a rolling bearing 50 for a servo motor shown in FIG. 10, there is a model in which an encoder 52 is arranged near a motor 51. For such a model, in order to prevent malfunction of the encoder 52 due to dust generation from inside the bearing and adhesion of seal wear powder to the encoder 52, a low-dust rolling bearing with a contact seal is required.

[0003] As prior arts, there are Patent Documents 1 and 2. Both of these prior documents propose a rolling bearing capable of reducing the amount of dust generated from inside the bearing even when the internal pressure of the bearing rises during rotation. Specifically, it defines the relative position of the core metal and the sub-lip, the shape of the tip of the contact seal lip in contact with the seal groove, and the slope of the seal groove.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] The above two prior documents are improvement proposals regarding dust generation from inside the bearing, and there is no problem as a shape proposal regarding dust generation property. Both of these prior documents have a structure in which the seal contacts the outer axial surface of the inner ring seal groove, and are effective regarding dust generation from inside the bearing due to an increase in internal pressure.

[0006] The sealing performance is ensured by the contact between the inner ring seal groove and the tip of the inner diameter lip of the seal (hereinafter referred to as the contact area). If this contact condition is not stable, it can cause dust generation from inside the bearing or leakage of base oil. In particular, since this seal contacts the inner ring seal groove with an overlap, it is important that the position of the contact area does not fluctuate significantly within the range of the overlap.

[0007] The inserted seal elastically deforms according to the interference fit, determining the position of the contact area. In the case of prior literature, the seal shape on the inner diameter side of the mandrel is prone to elastic deformation in the less rigid parts, resulting in a shape where the radial change of the contact area is large when the interference fit is changed within the expected range of interference fit. In the seals of prior literature, the shape affects the sealing performance when the inner ring oscillates axially due to thermal expansion or contraction of the shaft during bearing rotation, or when the interference fit changes during rotation due to changes in the internal pressure of the bearing.

[0008] In a seal that contacts the outside of an inner ring seal groove, the seal has a constricted portion where the wall thickness decreases in the shape from the core metal towards the inner diameter, and a bent portion that bends from the constricted portion to the tip of the inner diameter lip, and this seal is inserted into the bearing with an overlap. The position of the contact portion of the inserted seal changes according to the overlap. Normally, the less rigid part of the seal's shape from the core metal towards the inner diameter undergoes elastic deformation, and as shown in Figure 11, this elastically deformed part becomes the rotation center Pc, and the seal contact portion moves in a rotational trajectory Ty.

[0009] The seal's overlap during bearing rotation changes due to inner ring oscillation or pressure changes inside the bearing. When the radial contact position at the seal contact point changes due to the change in overlap, the contact point slides along the inner ring seal groove slope, causing the radial position to change and resulting in unstable sealing performance. In conventional lip structures with line contact, a large radial change in the contact point Δa can affect sealing performance.

[0010] As shown in Figure 12, the range of motion of the contact points changes along a roughly circular Cf passing through these three contact points Ps when the set clamping allowance is at its maximum, center, or minimum. The rotation center of this roughly circular Cf differs depending on the shape of the core metal 10 below its inner diameter. In order for the contact points Ps to move along the roughly circular Cf and for the radial position change to be small, it is desirable that the position of the contact points Ps at the center of the clamping allowance be directly below the rotation center in the radial direction. In other words, since the contact position changes along the roughly circular Cf, the amount of radial change is smallest when it is directly below the rotation center, and the inclination increases as it moves away from directly below.

[0011] In the conventional design, the center of rotation is near the constricted portion 14, and the axial position of this constricted portion 14 is on the bearing side of the contact portion Ps. Therefore, in order to position the contact portion on the approximate circumference, which is the range of motion of the lip tip, directly below the center of rotation, it is necessary to increase the interference fit, which increases the contact force and makes it more prone to wear. In addition, there is a possibility of increased rotational torque or the seal protruding from the bearing end face.

[0012] The objective of the present invention is to provide a rolling bearing that can stabilize sealing performance. [Means for solving the problem]

[0013] The rolling bearing of the present invention comprises an inner ring, an outer ring, a plurality of rolling elements interposed between the inner ring and the outer ring, and a sealing member that closes the bearing space between the inner ring and the outer ring, wherein the sealing member includes a core metal and a contact-type lip located radially inward from the core metal, and the lip has a contact portion that contacts the outside of the seal groove of the inner ring with an overlap, The sealing member is equipped with a radial change amount reduction means that reduces the radial change amount of the contact portion to a predetermined value or less within the range of the overlap. The aforementioned "specified value" is a value arbitrarily determined by design, etc., and is determined by finding an appropriate value through either or both of the following: testing and simulation.

[0014] According to this configuration, the radial variation reduction means reduces the radial variation of the contact portion of the lip to a predetermined value or less within the range of the interference fit. Therefore, even if the interference fit changes due to the oscillation of the inner ring or pressure changes inside the bearing during bearing rotation, the sealing performance with respect to the seal groove of the inner ring can be stabilized. This reduces the amount of dust generated from inside the bearing and prevents foreign matter from entering from outside the bearing.

[0015] The sealing member has a constricted portion located radially inward from the inner diameter portion of the core metal, the wall thickness decreasing towards the inner diameter side, a bent portion connected to the inner diameter portion of the constricted portion, and the lip connected to the inner diameter portion of the bent portion. The radial change reduction means is such that, when the overlap is at its maximum, the maximum axially outward protrusion position Pk of the bent portion is axially outward than the bottom Ks of the axially outward portion of the constricted portion, and is the same as or axially inward with respect to the axial position Tm of the end face of the inner or outer ring.

[0016] In this case, there is no change in the maximum axial distance on the bearing side of the entire seal member, and the bent portion does not protrude from the bearing end face. By adopting this shape for the seal member, the amount of elastic deformation at the bent portion increases. As a result, the rotation center of the approximately circular range of motion of the lip contact portion moves axially toward the bearing side, making it easier to set the position of the contact portion at the center of the overlap to be near directly below the rotation center. This makes it possible to reduce the amount of radial change of the lip contact portion compared to conventional structures.

[0017] It is desirable that the axial wall thickness Ta at the bottom of the constricted portion is greater than the radial wall thickness Tb from the inner diameter portion of the constricted portion to the inner circumferential surface of the bent portion. In this case, the amount of elastic deformation on the inner diameter side of the constricted portion can be increased. Therefore, the amount of radial change in the contact portion of the lip within the interference fit range can be made even smaller than in conventional structures.

[0018] The sealing member may be provided only on one axial side or on both axial sides of the rolling bearing. When the sealing member is provided only on one axial side, the number of parts can be reduced and the processing man-hours for the sealing groove and the like can be reduced, thereby reducing costs. When the sealing member is provided on both axial sides, the outflow of grease from the inside of the bearing and the intrusion of foreign matter from the atmosphere side can be suppressed.

Advantages of the Invention

[0019] The rolling bearing of the present invention includes an inner ring, an outer ring, a plurality of rolling elements interposed between the inner ring and the outer ring, and a sealing member that closes the bearing space between the inner ring and the outer ring. The sealing member includes a core metal and a contact lip located radially inward of the core metal. The lip has a contact portion that contacts the sealing groove of the inner ring with an interference fit. The sealing member is provided with a radial change amount reduction means for reducing the radial change amount of the contact portion within the range of the interference fit to a predetermined value or less. Therefore, the sealing performance can be stabilized.

Brief Description of the Drawings

[0020] [Figure 1] It is a longitudinal sectional view of a rolling bearing according to a first embodiment of the present invention. [Figure 2] It is a perspective view of a cage of the rolling bearing. [Figure 3] It is an enlarged sectional view showing an enlarged sealing member of the rolling bearing. [Figure 4] It is an enlarged sectional view of a lip or the like of the sealing member. [Figure 5] It is a view showing the radial change amount within the interference fit range of the contact portion of the lip. [Figure 6] It is a perspective view of the sealing member. [Figure 7] It is a longitudinal sectional view of a rolling bearing according to a second embodiment of the present invention. [Figure 8] It is a longitudinal sectional view of a rolling bearing according to a third embodiment of the present invention. [Figure 9] It is a longitudinal sectional view of a rolling bearing according to a fourth embodiment of the present invention. [Figure 10] This is a schematic diagram showing rolling bearings and the like for a servo motor. [Figure 11] This diagram shows the positional relationship between the center of rotation of the seal and the contact point as the overlap is from minimum to maximum. [Figure 12] This figure shows the change in seal when the tightening allowance changes. [Modes for carrying out the invention]

[0021] [First Embodiment] A rolling bearing according to an embodiment of the present invention will be described with reference to Figures 1 to 6. This rolling bearing is applicable to industrial machinery such as servo motors, vehicles, etc. However, the rolling bearing is not limited to these applications and can be applied to various machines, devices, etc.

[0022] <Outline configuration of a rolling bearing> Figure 1 shows a cross-section (longitudinal section) of the rolling bearing 1 as viewed by cutting it in a plane including the axial direction. The same applies to cross-sectional views of other embodiments. The rolling bearing 1 is a deep groove ball bearing comprising an inner ring 2, an outer ring 3, balls (rolling elements) 4, a cage 5, and a sealing member 6. Multiple balls 4 interposed between the raceway surfaces 2a, 3a of the inner and outer rings 2, 3 are held at regular intervals in the circumferential direction by the cage 5. The sealing member 6 is attached to the outer ring 3 and closes the bearing space, which is the annular space between the inner ring 2 and the outer ring 3. In this example, sealing members 6, 6 are attached to both sides of the axial direction on the inner circumferential surface of the outer ring. Grease, which is a lubricant, is sealed in the bearing space between the inner and outer rings 2, 3.

[0023] In this specification, rolling bearings are sometimes simply referred to as "bearings." In the following description, the direction of the bearing axis, which is the bearing center axis AX, is referred to as the "axial direction," the direction perpendicular to the bearing center axis AX is referred to as the "radial direction," and the direction around the bearing center axis AX is referred to as the "circumferential direction." Furthermore, the side facing the bearing center axis AX is referred to as the "inner diameter side," and the side moving away from the bearing center axis AX is referred to as the "outer diameter side."

[0024] <Cage> As shown in Figure 2, the retainer 5 in this example is made of synthetic resin and is a two-piece retainer formed by engaging two identical annular bodies 5a, 5a. This retainer 5 holds the ball 4 (Figure 1) in a pocket Pt whose axial pocket shape is cylindrical. Each annular body 5a has a plurality of semi-cylindrical pocket wall portions 5c and a plurality of connecting plate portions 5b. The pocket Pt is formed when two pocket wall portions 5c, 5c are combined with each other in the axial direction. The pockets Pt are arranged circumferentially. The retainer 5 has engaging holes Ka and engaging claws Kb in the connecting plate portions 5b between the pockets Pt that engage with each other. The retainer 5 is assembled by engaging the engaging claws Kb in the engaging holes Ka and engaging the two identical annular bodies 5a, 5a. The pocket shape of the retainer 5 may also be spherical.

[0025] <Regarding the seal structure, etc.> As shown in Figure 1, each sealing member 6 is a contact seal in which the main lip 15, which is the main lip, contacts the sealing groove 7 of the inner ring 2. The sealing groove 7 is formed in the circumferential direction on the outer surface of the inner ring 2, and a sealing groove 9 for fixing the sealing member is provided on the inner surface of the outer ring 3 opposite each sealing groove 7. As shown in Figure 3, the sealing member 6 is made by molding rubber material 11 onto a core metal 10, and the outer peripheral portion 8 of the sealing member 6 is fitted into the sealing groove 9 of the outer ring 3 and fixed. The main lip 15 is located radially inward from the core metal 10.

[0026] <Outer ring seal groove> The seal groove 9 of the outer ring 3 has an inner surface 9a, a groove bottom surface 9c, and an outer surface 9b in sequence, moving outward in the axial direction. The inner surface 9a connects to the outer ring shoulders provided on both sides of the raceway surface 3a (Figure 1) in the axial direction.

[0027] The groove bottom surface 9c, which smoothly connects to the inner surface 9a, has a shape that is recessed towards the radial outer diameter. The outer surface 9b smoothly connects to the groove bottom surface 9c and is formed as an inclined surface that slopes towards the inner diameter as it extends axially outward. In Figures 1 and 3, a portion of the outer circumference of the seal member 6 is shown to be embedded in the seal groove 9 of the outer ring 3, but this portion is an overlap and is actually fitted into the seal groove 9 in an elastically deformed state. The same applies to the seal structures shown in Figures 7 to 9, which will be described later.

[0028] As shown in Figure 4, a main lip (contact-type lip) 15 is provided on the inner circumference portion 13 of the sealing member 6, which contacts the outer surface 7c of the sealing groove 7 of the inner ring 2. The main lip 15 has a contact portion 15c that contacts the sealing groove 7 of the inner ring 2 in a state of elastic deformation with an overlap. In Figures 1 and 3, a portion of the main lip 15 of the sealing member 6 is shown to be embedded in the sealing groove 7 of the inner ring 3. However, this portion is an overlap and actually contacts the sealing groove 7 in an elastically deformed state. The same applies to the sealing structures shown in Figures 7 to 9, which will be described later.

[0029] <Air vent> As shown in Figure 6, the outer peripheral portion 8 (Figure 3) of the sealing member 6 is provided with multiple air holes 12 to release the internal pressure of the rolling bearing. These air holes 12 include radial air holes 12a, 12a formed along the radial direction and axial air holes 12b formed along the axial direction. The air holes 12a, 12b each consist of grooves provided in the outer peripheral portion 8 (Figure 3) of the sealing member 6. These radial air holes 12a, 12a and the axial air holes 12b are provided at different circumferential positions. The number and circumferential positions of the air holes 12a, 12b are not limited to those shown in Figure 6.

[0030] As shown in Figures 3 and 6, the radial air holes 12a, 12a and the axial air hole 12b are in communication via the groove bottom surface 9c of the seal groove 9. Therefore, when the rolling bearing 1 (Figure 1) rotates, the internal pressure of the bearing can be released to the outside through the two radial air holes 12a, 12a and the axial air hole 12b.

[0031] <Inner ring seal groove> As shown in Figure 1, the seal groove 7 of the inner ring 2 has an inner surface 7a, a groove bottom surface 7b, and an outer surface 7c in sequence as it moves outward in the axial direction. The inner surface 7a connects to the inner ring shoulders provided on both sides of the raceway surface 2a in the axial direction and is formed as an inclined surface that slopes inward toward the inner diameter as it moves outward in the axial direction. The groove bottom surface 7b, which smoothly connects to this inner surface 7a, has a shape that is recessed toward the inner diameter. The outer surface 7c connects smoothly to the groove bottom surface 7b and is formed as an inclined surface that slopes outward toward the outer diameter as it moves outward in the axial direction.

[0032] As shown in Figure 3, the rubber material 11 in the sealing member 6 is typically made of nitrile rubber, but other materials such as acrylic rubber, silicone rubber, or fluororubber may be used depending on the operating temperature.

[0033] <Lipstick, etc.> As shown in Figure 4, the inner circumferential portion 13 of the sealing member 6, which extends radially inward from the inner diameter portion of the core metal 10, is made of the rubber material 11. The inner circumferential portion 13 has a constricted portion 14, a bent portion Be, a main lip 15, and a sub-lip 16. The constricted portion 14 is located radially inward from the inner diameter portion of the core metal 10, and its wall thickness decreases as it moves toward the inner diameter. The bent portion Be connects to the inner diameter portion of the constricted portion 14 and extends axially outward, bending, or elastically deforming, the inner circumferential portion 13 including the main lip 15.

[0034] The main lip 15 connects to the inner diameter portion of the bent portion Be. The sub-lip 16 connects to the axially inner surface of the bent portion Be. The sub-lip 16 protrudes axially inward from the axially inner surface of the bent portion Be and, as shown in Figure 1, is not in contact with the seal groove 7 of the inner ring 2. A labyrinth seal Rs is formed between the tip of the sub-lip 16 and the inner surface 7a of the seal groove 7. As shown in Figure 4, the constricted portion 14, the bent portion Be, the main lip 15, and the sub-lip 16 are integrally molded. Integral molding means that the constricted portion 14, the bent portion Be, the main lip 15, and the sub-lip 16 are not formed by combining multiple elements, but are formed from a single material, for example by injection molding, as part of or as a whole of a single object.

[0035] Of the bent portion Be, the outer circumferential surface facing the axially outer portion of the constricted portion 14 is formed as an inclined surface Bea that slopes inward toward the inner diameter as it extends axially outward. The angle α1 between this inclined surface Bea of ​​the bent portion Be and the axially outer portion of the constricted portion 14 is set to an acute angle within the range of the overlap that the main lip 15 contacts the seal groove 7.

[0036] The main lip 15 has a lip body portion 15b that inclins axially inward as it approaches the inner diameter, and a contact portion 15c provided on the outer surface portion of the tip side of the lip body portion 15b. This contact portion 15c is also referred to as the inner diameter tip portion. The contact portion 15c contacts the seal groove 7 of the inner ring 2. Specifically, the contact portion 15c is formed in an R shape that is normal to the outer surface 7c of the seal groove 7. The outer diameter surface 15ca of the contact portion 15c inclins axially outward as it approaches the inner diameter and smoothly connects to the R shape.

[0037] <Means for reducing radial change amount> In Figure 5, the solid line indicates the position of the contact portion 15c when the set tightening allowance is at its minimum, the dashed-dot line indicates the position of the contact portion 15c when the tightening allowance is in the center, and the dashed-dot line indicates the position of the contact portion 15c when the tightening allowance is at its maximum. As shown in Figures 4 and 5, the sealing member 6 is equipped with a radial change amount reduction means Rcr that reduces the radial change amount Δa of the contact portion 15c to a predetermined value or less within the said tightening range. The radial change amount reduction means Rcr reduces the radial change amount Δa within the tightening range by changing the seal shape of the inner circumference portion 13 located on the inner diameter side of the core metal 10. Specifically, the bent portion Be, which bends on the inner diameter side of the constricted portion 14, is made to protrude axially toward the anti-bearing side, i.e., axially outward. As a result of making this bent portion Be protrude axially outward, the angle α1 formed by the inclined surface Bea of ​​the bent portion Be and the axially outward portion of the constricted portion 14 becomes an acute angle within the said tightening range.

[0038] The axial protrusion amount of the bent portion Be is such that, in the state of maximum interference fit, the bottom Ks of the constricted portion 14 < the maximum protrusion position Pk of the bent portion Be ≤ the end face (also called the [width face]) of the inner or outer ring. In other words, the radial change amount reducing means Rcr ensures that, when the interference fit is at its maximum, the maximum axially outward protrusion position Pk of the bent portion Be is axially outward from the bottom Ks of the axially outward portion of the constricted portion 14, and is the same as or axially inward with respect to the axial position Tm of the end face of the inner or outer ring. Here, axially inward refers to the direction inside the bearing. Furthermore, the axial wall thickness Ta at the bottom Ks of the constricted portion 14 is greater than the radial wall thickness Tb (wall thickness at the base of the constricted portion) from the inner diameter portion of the constricted portion 14 to the inner circumferential surface Beb of the bent portion Be.

[0039] <Effects and Effects> As described above, the radial variation reduction means Rcr reduces the radial variation Δa of the contact portion 15c of the main lip 15 to a predetermined value or less within the range of the overlap. Therefore, even if the overlap changes during bearing rotation due to the oscillation of the inner ring or pressure changes inside the bearing, the sealing performance of the inner ring 2 to the seal groove 7 can be stabilized. This reduces the amount of dust generated from inside the bearing and prevents foreign matter from entering from outside the bearing.

[0040] The axial protrusion amount of the bent portion Be is such that, in the state of maximum interference fit, the bottom Ks of the constricted portion 14 < the maximum protrusion position Pk of the bent portion Be ≤ the end face of the inner or outer ring. In this case, there is no change in the maximum distance on the axial side opposite the bearing for the entire seal member, and the bent portion Be does not protrude from the bearing end face. By making the seal member 6 this shape, the amount of elastic deformation at the bent portion Be increases. As a result, the rotation center of the approximately circular range of motion of the contact portion 15c of the main lip 15 moves axially toward the side opposite the bearing, making it easier to set the position of the contact portion 15c at the center of the interference fit to be near directly below the rotation center. This makes it possible to reduce the radial change amount Δa of the contact portion 15c of the main lip 15 compared to the conventional structure.

[0041] Furthermore, if Ta > Tb, the amount of elastic deformation on the inner diameter side of the constricted portion 14 can be increased. As a result, the amount of radial change Δa of the contact portion 15c of the main lip 15 within the interference fit range can be made even smaller than in the conventional structure.

[0042] In addition to the sealing member 6 being equipped with a means Rcr for reducing radial change, the contact portion 15c connected to the lip body portion 15b is formed in an R shape that is normal to the outer surface 7c of the sealing groove 7. As a result, even when the internal pressure of the rolling bearing 1 (Figure 1) increases during rotation, the main lip 15 can suppress the intrusion of foreign matter from the atmosphere and suppress changes in the surface pressure distribution of the main lip 15. Therefore, it is possible to suppress unwanted increases in torque and unwanted overheating of the main lip 15.

[0043] As shown in Figure 6, an air hole 12 is provided on the outer peripheral portion 8 (Figure 3) of the seal member 6 to release the internal pressure of the rolling bearing 1 (Figure 1). Therefore, by releasing the internal pressure of the bearing through the air hole 12 when the rolling bearing 1 (Figure 1) rotates, it is possible to suppress excessive changes in the tightening allowance of the seal member 6 and the outflow of grease caused by an increase in the internal pressure of the bearing.

[0044] <Regarding other embodiments> In the following description, parts corresponding to matters previously described in each embodiment will be denoted by the same reference numerals, and redundant explanations will be omitted. When only a part of the configuration is described, the other parts of the configuration will be the same as those in the previously described embodiment unless otherwise specified. Identical configurations will produce the same effects. Not only are combinations of the parts specifically described in each embodiment possible, but partial combinations of embodiments are also possible, provided that there are no particular problems with the combination.

[0045] [Second embodiment: Figure 7, one-sided seal] As shown in Figure 7, the sealing member 6 may be provided only on one axial side of the rolling bearing 1. In this case, the number of parts and the number of machining steps for seal grooves, etc., can be reduced compared to a rolling bearing with sealing members on both axial sides, thereby reducing costs.

[0046] [Third embodiment: Figure 8, crown-shaped retainer] As shown in Figure 8, the retainer 5 may be a so-called crown-shaped retainer with an opening on one axial side of the pocket Pt. In this case, the number of parts of the retainer 5 can be reduced compared to the two-piece retainer described above, thereby reducing the assembly man-hours.

[0047] [Fourth embodiment: Figure 9, one-sided seal] As shown in Figure 9, in a rolling bearing 1 equipped with a crown-shaped cage 5, the sealing member 6 may be provided only on one axial side of the rolling bearing 1.

[0048] In each embodiment, it is also possible to omit the air holes on the outer periphery of the sealing member. In other words, the sealing member may be configured without air holes. In deep groove ball bearings, corrugated steel cages may be used. Rolling bearings equipped with means for reducing radial variation are not limited to deep groove ball bearings, but can be applied to various types of bearings such as angular contact ball bearings, tapered roller bearings, and cylindrical roller bearings.

[0049] While embodiments for carrying out the present invention have been described above based on the embodiments, the embodiments disclosed herein are illustrative in all respects and are not restrictive. The scope of the present invention is indicated by the claims rather than the foregoing description, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of symbols]

[0050] 1...Rolling bearing, 2...Inner ring, 3...Outer ring, 4...Ball (rolling element), 6...Seal member, 7...Seal groove, 10...Core metal, 14...Necked section, 15...Main lip (contact type lip), 15c...Contact section, Be...Bent section, Ks...Bottom section, Pk...Maximum protrusion position, Δa...Radial change amount, Rcr...Means for reducing radial change amount, Tm...Axial position of end face

Claims

1. A rolling bearing comprising an inner ring, an outer ring, a plurality of rolling elements interposed between the inner ring and the outer ring, and a sealing member that closes the bearing space between the inner ring and the outer ring, wherein the sealing member includes a core and a contact-type lip located radially inward from the core, and the lip has a contact portion that contacts the seal groove of the inner ring with an overlap, The sealing member is a rolling bearing equipped with means for reducing the amount of radial change of the contact portion to a predetermined value or less within the range of the clamping allowance.

2. In the rolling bearing according to claim 1, the sealing member has a constricted portion located radially inward from the inner diameter portion of the mandrel and whose wall thickness decreases toward the inner diameter side, a bent portion connected to the inner diameter portion of the constricted portion, and the lip connected to the inner diameter portion of the bent portion, The radial change reduction means is a rolling bearing in which, at the maximum overlap, the maximum axially outward protrusion position Pk of the bent portion is axially outward than the bottom Ks of the axially outward portion of the constricted portion, and is the same as or axially inward with respect to the axial position Tm of the end face of the inner ring or outer ring.

3. A rolling bearing according to claim 2, wherein the axial wall thickness Ta at the bottom of the constricted portion is greater than the radial wall thickness Tb from the inner diameter portion of the constricted portion to the inner circumferential surface of the bent portion.

4. A rolling bearing according to claim 1 or claim 2, wherein the sealing member is provided on only one axial side or on both axial sides of the rolling bearing.

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