JP2022128915A - Bearing with seal - Google Patents

Abstract

To inhibit stick-slip phenomenon of multiple projections of a seal lip in a bearing with a seal which can turn an area between a seal lip and a seal slide surface into a fluid lubrication state with the projections.SOLUTION: A projection 12 has corner parts 12a, 12b which curve from an intermediate portion as seen in a height direction of the projection 12 to a root in a direction such that a circumferential width W of the projection 12 is gradually widened. Thereby, improves the strengh of areas near the root of the projection 12 is improved to inhibit stick-slip phenomenon.SELECTED DRAWING: Figure 5

Description

The present invention relates to a sealed bearing comprising a rolling bearing and a sealing member.

Sealing members are used to prevent premature failure of rolling bearings. For example, in transmissions mounted on vehicles such as automobiles and various construction machines, foreign matter such as wear powder of gears is mixed, so a seal member prevents the wear powder from entering the inside of the bearing.

In general, the sealing member has an annular sealing lip made of rubber-like material or the like. A mating part such as a bearing ring, a slinger, or the like, which rotates relative to the seal member in the circumferential direction as the bearing rotates, is formed with a seal sliding surface that makes sliding contact with the seal lip.

In a general seal member, the seal lip and the seal sliding surface are in sliding contact with each other around the entire periphery, and microscopically, there is a solid contact area. The drag resistance (seal torque) of the seal lip causes an increase in bearing torque. Moreover, the sliding contact contributes to the temperature rise of the rolling bearing. In addition, since the inside of the bearing is closed off from the outside by the seal member, the pressure difference between the inside and the outside of the bearing causes the seal lip to press against the seal sliding surface, causing an adsorption effect, which may increase the seal torque. For these reasons, there is a limit to the high-speed operation of bearings with common sealing members.

If the seal lip of the seal member is arranged so as not to contact the mating part and forms a labyrinth seal, it is possible to eliminate the seal torque. It is difficult to manage various errors that can be prevented.

On the other hand, the seal lip has a plurality of projections arranged in the circumferential direction. A seal-equipped bearing has been proposed in which the seal lip and the seal sliding surface can be brought into a fluid lubrication state by an oil film of lubricating oil that is dragged between the projection and the seal sliding surface through the gap (Patent Document 1). .

In the bearing with seal of Patent Document 1, lubrication on the seal sliding surface is achieved by allowing lubricating oil to flow between the internal space and the outside of the rolling bearing through a gap that can prevent foreign matter of a predetermined particle size from entering. Lubricating with oil, the wedge effect when lubricating oil is drawn between the projections and the seal sliding surface as the bearing rotates forms a thick oil film, completely separating each projection and the seal sliding surface with the oil film. , a fluid lubricating state can be established between the seal lip and the seal sliding surface. Therefore, according to the sealed bearing of Patent Document 1, the seal torque can be significantly reduced while preventing the intrusion of foreign matter of a predetermined particle size and enabling the bearing to operate at high speed.

WO2016/143786

In the seal lip of Patent Document 1, from when the bearing is stopped until the bearing rotation speed reaches a predetermined value or more (when the relative circumferential speed between the protrusion and the seal sliding surface is less than a certain value), the protrusion and the seal sliding surface There is no fluid lubrication between them, but boundary lubrication or mixed lubrication including solid contact areas. Therefore, at the beginning of rotation after the bearing is stopped, the protrusion is dragged in the circumferential direction with respect to the seal sliding surface in the solid contact area.

However, in the seal lip of Patent Document 1, since the base of the protrusion is angled when viewed from the gap side, the elasticity of the protrusion that is dragged in the solid contact area with the seal sliding surface at the beginning of rotation after the bearing is stopped. Deformation may cause a non-uniform stick-slip phenomenon such as the Charmac wave peculiar to rubber generated by static friction.

In view of the above-mentioned background, the problem to be solved by the present invention is to provide a seal bearing in which a plurality of protrusions on the seal lip can establish a fluid lubrication state between the seal lip and the seal sliding surface. It is to suppress the phenomenon.

In order to achieve the above object, the present invention includes a seal member that seals the internal space of a rolling bearing from the outside, and a seal sliding surface that slides in the circumferential direction against the seal member, and the seal is The member has a seal lip formed in an annular shape, the seal lip has a plurality of projections arranged in a circumferential direction, and the plurality of projections extend through the inner space between the circumferentially adjacent projections. A gap that communicates with the space and the outside is generated, and a fluid is maintained between the seal lip and the seal sliding surface by an oil film of lubricating oil that is dragged from the gap between the protrusion and the seal sliding surface as the bearing rotates. In the bearing with a seal that is formed in a manner that can be lubricated, the projection gradually widens in the circumferential direction from the intermediate portion in the height direction of the projection to the root. A configuration having corners curved in the direction was adopted.

According to the above configuration, since the corner portion is curved so as to widen the width in the circumferential direction in the range from the mid-height portion of the projection to the root, the strength of the vicinity of the root of the projection is improved, so that the bearing can be At the beginning of rotation from the time of stop, it is possible to suppress elastic deformation when the projection is dragged in the circumferential direction in the solid contact area with the seal sliding surface, and thus the stick-slip phenomenon of the projection can be suppressed.

The ratio of the corner portion to the height of the projection is preferably 30% or less. In order to maintain fluid lubrication between the protrusion and the seal sliding surface from low speed rotation of the bearing, the wedge-shaped gap between the protrusion and the seal sliding surface should provide an appropriate wedge effect, and the oil film should not be cut at the top of the protrusion. It is necessary to Therefore, between the top of the protrusion and the intermediate portion, a sufficiently curved surface shape must be formed so as to gradually recede from the seal sliding surface. By setting the ratio of the height of the corner portion to the height of the protrusion to be 30% or less, the height of the corner portion is not increased unnecessarily, and a sufficient wedge-shaped gap can be formed.

Moreover, it is preferable that the projection has the corner portions on both sides in the circumferential direction of the projection. In this way, the strength can be improved by widening the width in the circumferential direction to both sides in the vicinity of the base of the projection.

Moreover, it is preferable that the corner portion is formed over the entire length of the projection. By doing so, the strength of the vicinity of the base of the projection can be improved by utilizing the entire length of the projection without waste.

Further, the combined roughness σ of the protrusion and the seal sliding surface is preferably 0.9 μm or less. This is suitable for bringing the sliding portion between the projection and the seal sliding surface into a fluid lubricating state in which stick-slip phenomenon does not occur from an extremely low peripheral speed.

The present invention suppresses the stick-slip phenomenon of the protrusions in a bearing with a seal that can maintain a fluid lubricating state between the seal lip and the seal sliding surface by means of the plurality of protrusions on the seal lip by adopting the above configuration. be able to.

1 is a cross-sectional view showing a sealed bearing according to an embodiment of the present invention; FIG. 2 is a partial sectional view showing the natural state of the seal lip of FIG. 1; Enlarged left side view near the protrusion in FIG. Enlarged view of the vicinity of the protrusion in Fig. 1 Enlarged right side view near the protrusion in FIG. Graph showing the measurement results of the coefficient of friction of a test piece with a rubber strength of 70Hs Graph showing the measurement results of the coefficient of friction of a test piece with a rubber strength of 75Hs

A sealed bearing according to an embodiment of the present invention will be described with reference to FIGS. 1 to 6 of the accompanying drawings.

This sealed bearing shown in FIG. 1 comprises a rolling bearing 1 and two sealing members 2 arranged on both sides of the rolling bearing 1 .

A rolling bearing 1 is composed of an inner ring 3, an outer ring 4, a predetermined number of rolling elements 5 interposed between the inner ring 3 and the outer ring 4, and a retainer 6 that holds the predetermined number of rolling elements 5. . The sealing member 2 seals the inner space 7 of the rolling bearing 1 from the outside. The purpose of this sealing is to prevent foreign matter from entering the inner space 7 between the inner and outer rings 3 and 4, which is the periphery of the sealed bearing, and prevent early damage to the rolling bearing 1. It is not to seal the space 7 in a liquid-tight manner.

The inner ring 3 and the outer ring 4 have raceway surfaces corresponding to the rolling elements 5 . The inner ring 3 is attached to the rotating shaft S and rotates together with the rotating shaft S. The outer ring 4 is attached to a member such as a housing, a gear, or the like that applies a load from the rotating shaft. The rolling elements 5 revolve while being interposed between the inner ring 3 and the outer ring 4 .

A ball is adopted as the rolling element 5 . This sealed bearing is a deep groove ball bearing.

The internal space 7 is lubricated with lubricating oil (not shown; hereinafter the same) supplied from the outside. Lubricating methods include, for example, a splashing method in which lubricating oil is applied to the bearing with a seal, and an oil bath method in which the lower portion of the bearing with a seal is immersed in an oil bath. An appropriate amount of grease may be filled in the internal space 7 as an initial lubricant.

The rotating shaft S is provided as a rotating part provided in any one of a vehicle transmission, differential, constant velocity joint, propeller shaft, turbocharger, machine tool, wind power generator, and wheel bearing, for example.

In the following description, the direction along the center axis of the sealed bearing (not shown; hereinafter the same) will be referred to as the "axial direction". A direction orthogonal to the axial direction is called a “radial direction”. The circumferential direction around the bearing center axis is called the “circumferential direction”. In the illustrated example, the bearing center axis is the center axis of the inner ring 3 which is a rotating ring, and corresponds to the left-right direction in the figure.

A seal groove 8 for holding the seal member 2 is formed at the end of the inner circumference of the outer ring 4 . The seal member 2 is attached to the outer ring 4 by press-fitting its outer peripheral edge into the seal groove 8 .

In the outside surrounding the bearing with seal, there are foreign matter depending on where the bearing with seal is incorporated, such as wear powder of gears, wear powder of clutch, fine crushed stones, and the like. Such powdery foreign matter can reach the vicinity of the seal member 2 due to the flow of lubricating oil or atmosphere. The sealing member 2 is for preventing foreign matter from entering the internal space 7 from the outside.

The seal member 2 has a core metal 9 made of a metal plate and a seal lip 10 formed in an annular shape. The cored bar 9 is a press-worked part that is annularly formed and continues in the circumferential direction. The seal lip 10 is made of vulcanized rubber. Examples of rubber materials include nitrile rubber (NBR), acrylic rubber (ACM), and fluororubber (FKM).

A seal sliding surface 11 that slides on the seal lip 10 in the circumferential direction is formed on the outer periphery of the inner ring 3 . The seal sliding surface 11 is in the shape of a cylindrical surface that continues along the entire circumferential direction.

The seal lip 10 is a radial lip. Here, the radial lip is a seal lip that exerts a sealing action with a seal sliding surface along the axial direction or a seal sliding surface having an acute angle gradient of 45° or less with respect to the axial direction. It has a radial interference between it and the moving surface.

FIG. 2 shows the cross-sectional shape (shape at the time of molding) when the seal lip 10 is in a natural state by itself. The seal lip 10 has an annular waist portion which is radially continuous with a constant width in the axial direction, and a head portion which is shaped like a projecting piece that curves outward from the waist portion.

The head of the seal lip 10 has a leading edge that defines the inner diameter of the seal lip 10 in the state of FIG. 1, the seal lip 10 is pressed against the seal sliding surface 11 due to the interference with the seal sliding surface 11, and deforms rubber-like elastically to the outside. , produces a straining force of the seal lip 10 . Mounting errors, manufacturing errors, etc. of the seal member 2 are absorbed by changes in the degree of bending of the seal lip 10 .

FIG. 3 shows an enlarged left side view of the vicinity of the head portion of the seal lip 10 of FIG. FIG. 4 shows an enlarged view of the vicinity of the head portion of the seal lip 10 of FIG. FIG. 5 shows an enlarged right side view of the vicinity of the head portion of the seal lip 10 of FIG.

As shown in FIGS. 3 to 5, the seal lip 10 has a plurality of projections 12 arranged in the circumferential direction.

As shown in FIG. 3, the protrusions 12 extend in a direction orthogonal to the circumferential direction. Each protrusion 12 is located in a line with a fixed pitch in the circumferential direction. The entire length of the protrusion 12 extends over the entire range with a radial interference between the protrusion 12 and the seal sliding surface 11 . The overall shape of the seal lip 10 is rotationally symmetrical corresponding to the pitch of the protrusions 12 .

When the seal member 2 is attached to the rolling bearing 1 as shown in FIG. The protrusion 12 has a height in a direction perpendicular to the seal sliding surface 11 on a virtual plane including the bearing center axis. The protrusion 12 stretches against the straining force of the seal lip 10. - 特許庁As a result, as shown in FIGS. 4 and 5 , a gap 13 communicating with the internal space 7 and the outside is generated between the protrusions 12 adjacent in the circumferential direction and between the seal sliding surface 11 and the seal lip 10 . Let me. The channel cross-sectional height of the gap 13 corresponds to the radial distance between the seal sliding surface 11 and the lip portion connecting the protrusions 12 adjacent in the circumferential direction. The seal lip 10 slides on the seal sliding surface 11 only on the plurality of protrusions 12, and the lip portion connecting the protrusions 12 adjacent in the circumferential direction is kept in a non-contact state with the seal sliding surface 11. It's like

As shown in FIG. 5 , the projection 12 has a shape such that it gradually moves away from the seal sliding surface 11 from the center portion in the circumferential direction of the projection 12 toward both sides in the circumferential direction. Therefore, the protrusion 12 forms a wedge-shaped gap with the seal sliding surface 11 that is large on the gap 13 side and small on the protrusion 12 side.

The projection 12 has a corner portion 12a formed from the root on one side in the circumferential direction of the projection 12, a corner portion 12b formed from the root on the other side in the circumferential direction of the projection 12, and a tip of the projection 12 extending from the corner portions 12a and 12b. It is composed of a top portion 12c that continues up to.

The corner portions 12a and 12b are formed in a curved surface that gradually widens the circumferential width W of the projection 12 from the middle portion in the height direction of the projection 12 to the root of the projection 12 toward the root.

Here, the height h1 of the projections 12 refers to the difference in height from the lip portion connecting the circumferentially adjacent projections 12 to the tip of the projection 12 on _a virtual plane orthogonal to the central axis of the bearing. The height direction of the protrusion 12 is the straight line direction forming the height h1 _on the same imaginary plane, and the circumferential width W of the protrusion 12 is the circumference between both ends of the protrusion 12 in the circumferential direction on the same imaginary plane. Refers to directional length.

All of the projections 12 are solid portions and have a symmetrical shape with respect to an imaginary plane perpendicular to the bearing center axis and passing through the bisector of the width W in the circumferential direction. The height h ₁ of the protrusion 12 is constant over the entire length of the protrusion 12 .

The corner portions 12a and 12b each have a rounded corner shape when viewed from the gap 13 side. The top portion 12c has an arcuate shape extending between the corner portions 12a and 12b. The curvature radius _R1 of the top portion 12c and the curvature radius _R2 of the corner portions 12a and 12b are set so that the _ratio of the corner portions 12a and 12b to the height h1 of the projection 12 is 30% or less. . That is, the value of the height h2 of the corner portions 12a and 12b is _0.3h1 or _less .

The corner portions 12a and 12b are formed over the entire length of the projection 12, respectively.

The corner portions 12a and 12b are protruding when the top portions 12c of the protrusions 12 are dragged in the circumferential direction against the seal sliding surface 11 when the protrusion 12 and the seal sliding surface 11 are in a lubricating state in which a solid contact area exists between the protrusions 12 and the seal sliding surface 11. The purpose is to improve the strength of the protrusion 12 so that elastic deformation of the protrusion 12 from the vicinity of the root can be suppressed.

A test was conducted to determine whether improving the strength of the projections 12 is effective in suppressing a stick-slip phenomenon such as Charmac waves. The test was conducted in accordance with JIS P8147:2010. In each measurement, the coefficient of friction μ was measured when a rubber test piece exhibiting a predetermined Shore hardness was reciprocated three times in succession. FIG. 6 shows the measurement results of the 70Hs rubber test piece, and FIG. 7 shows the measurement result of the 75Hs rubber test piece. In FIGS. 6 and 7, the reciprocating motion starts about 5 seconds after the measurement time (horizontal axis). Comparing the changes in the coefficient of friction μ in the graphs of Figs. It is remarkably small compared to the amount of change in the coefficient. Therefore, it can be seen that improving the strength of the rubber portion is effective in suppressing the stick-slip phenomenon.

The corner portions 12a and 12b illustrated in FIG. 5 each have a corner R shape forming a single arcuate surface shape, but the circumferential width W of the projection 12 is expanded near the root and the stress concentration at the root is alleviated. By forming a curved shape without corners, the strength of the projection 12 is improved from the viewpoint of resistance to deformation of the projection 12 against dragging in the circumferential direction, and the projection 12 and the seal slide in a lubricated state where a solid contact area exists. The stick-slip phenomenon can be suppressed between the surfaces 11, and ideally, a curved shape that does not cause the stick-slip phenomenon should be formed.

As shown in FIG. 4, the top portion 12c of the protrusion 12 has a region generally along the seal sliding surface 11 on a virtual plane including the bearing center axis. This region has a width in the direction along the seal sliding surface 11 (corresponding to the axial direction in the illustrated example). Therefore, there is a wedge effect when the protrusion 12 and the seal sliding surface 11 slide along with the rotation of the bearing, that is, when the protrusion 12 drags the lubricating oil in the gap 13 in the circumferential direction between the seal sliding surface 11 and the protrusion 12. promotes the formation of an oil film, and the area where the oil film is interposed between the top portion 12c of the protrusion 12 and the seal sliding surface 11 is a predetermined or more area in the direction along the seal sliding surface 11 on the imaginary plane of the figure. occurs in finite length L. Such a sliding portion between the protrusion 12 and the seal sliding surface 11 is considered to occur in a contact elliptical shape based on Hertz's theory of elastic contact.

In the sliding portion between the projection 12 and the seal sliding surface 11, the shear resistance of the lubricating oil between the rounded top portion 12c of the projection 12 and the seal sliding surface 11 is suppressed as described above, and the circumference of the projection 12 is reduced. Since the projection 12 is prevented from cutting off the oil film by avoiding sharpening of the central portion in the direction, the wedge effect promotes the formation of the oil film effectively. Therefore, when the peripheral speed of the relative rotation of the projection 12 and the seal sliding surface 11 becomes more than a certain value due to the rotation of the bearing, the oil film thickness between the projection 12 and the seal sliding surface 11 is , and each protrusion 12 and the seal sliding surface 11 are completely separated by an oil film, resulting in a fluid lubrication state. As a result, a fluid lubrication state in which the seal lip 10 and the seal sliding surface 11 are completely separated by an oil film can be achieved. In such a fluid lubrication state, the seal torque by the seal member 2 can be reduced to the same level as that of a non-contact type seal, thereby suppressing the temperature rise of the bearing with seal and preventing the adsorption action of the seal lip 10. can. When the peripheral speed is less than a certain value after the bearing is stopped, microscopically, a boundary lubrication state or a mixed lubrication state including a solid contact area occurs.

For example, in applications that support rotating parts in vehicle transmissions, sealed bearings are typically lubricated by any suitable method, such as a splash, oil bath, or the like. Therefore, lubricating oil supplied from the outside exists around the seal lip 10 . The lubricating oil is also commonly used for other lubricating parts such as gears present in the transmission. The lubricating oil is circulated by an oil pump and filtered by an oil filter provided in the circulation path. If a large foreign matter with a grain size exceeding 0.05 mm enters the internal space 7, it is considered to have an adverse effect on the life of the bearing. By setting the height of the protrusion 12 to 0.07 mm or less, it is possible to create a gap 13 through which such a large foreign matter cannot easily pass. When the height h1 of the projections ₁₂ is 0.07 mm or less, for example, the interval between the projections 12 adjacent in the circumferential direction is 0.3 mm or more and 2.6 mm or less, and the circumferential width W of the projections 12 is 0.2 mm or more. 0 mm or less, and the radius of curvature _R1 of the top portion 12c of the protrusion 12 can be set in the range of 0.15 mm or more and less than 2.0 mm. In this example, when the oil temperature is 30 to 120° C. and the relative peripheral speed of the seal lip 10 and the seal sliding surface 11 is 0.2 m/s or more, the dimensionless number determined by Greenwood-Johnson is In the lubrication region diagram (Johnson chart) based on the viscous parameter gv and the elastic parameter ge, either the constant viscosity-rigid region (RI mode) or the constant viscosity-elastic region (EI mode, soft EHL) It is considered to be in the lubrication mode, that is, the fluid lubrication state described above.

When the above-mentioned interval is 2.6 mm, an oil film of approximately 3 μm is formed between the protrusion 12 and the seal sliding surface 11, and when the interval is smaller than 2.6 mm, the oil film tends to be thicker. be. Further, when the above-described interval is 2.6 mm or less, the bearing rotating torque tends to decrease (that is, the seal torque tends to decrease). If the above-described interval is less than 0.3 mm, it becomes difficult to process the transfer surface for forming the protrusions 12 on the mold with a ball end mill. Considering molding with a mold, it is preferable to set the radius of curvature _R1 of the top portion 12c of the protrusion 12 to 0.15 mm or more and less than 2.0 mm. Since the circumferential width W of the projection 12 correlates with the curvature radius _R1 , it is preferable to set the circumferential width W of the projection 12 to 0.2 mm or more and 1.0 mm or less.

Here, if the oil film parameter Λ≧3, the lubrication mode of the sliding portion is considered to be fluid lubrication. The oil film parameter Λ is the ratio of the combined roughness σ to the minimum oil film thickness h on the sliding portion, where Λ=h/σ. The minimum oil film thickness h is obtained based on elastohydrodynamic lubrication theory. The combined roughness σ=√((Rq ₁ ² +Rq ₂ ² )/2). Rq ₁ is the root-mean-square roughness of the seal sliding surface 11 forming the aforementioned sliding portion. _Rq2 is the root-mean-square roughness of the surface of the projection 12, and the root-mean-square roughness is the value (μm) of the root-mean-square roughness Rq defined in JIS (B0601:2013).

The oil film parameter Λ depends on the synthetic roughness σ, and the smaller the synthetic roughness σ, the thicker the oil film can be. In order to keep the sliding portion between the protrusion 12 and the seal sliding surface 11 in a fluid lubrication state from the time when the peripheral speed is extremely low, it is preferable to set the combined roughness σ of the sliding portion to 0.9 μm or less. For example, under the calculation conditions of synthetic roughness σ of 0.9 μm, transmission oil (30 cst, 40° C.) as lubricating oil, ambient temperature of 20° C., and peripheral speed of 0.2 m/s, the oil lubrication mode was determined using a Johnson chart. However, the minimum oil film thickness h was 2.8 μm, the oil film parameter Λ was 3 or more, and the lubrication mode was the EI mode. Therefore, if the combined roughness σ of the protrusion 12 and the seal sliding surface 11 is 0.9 μm or less, it is expected that the bearing will reliably be in a fluid lubricating state in the actual usage range.

In this bearing with seal, as described above, the seal lip 10 and the seal sliding surface 11 can be brought into a state of fluid lubrication by the plurality of projections 12 of the seal lip 10. Since the corner portions 12a and 12b are curved in a direction to gradually widen the circumferential width W of the projection 12 from the intermediate portion in the height direction to the root, the strength of the vicinity of the root of the projection 12 is improved and the rolling resistance is improved. At the beginning of rotation after the bearing 1 is stopped, it is possible to suppress the stick-slip phenomenon of the protrusion 12 by suppressing the elastic deformation when the protrusion 12 is dragged in the circumferential direction in the solid contact area with the seal sliding surface 11. can.

As a result, the seal lip 10 can be used in places where the transmission stationary state, that is, the stop state of the rotating part (rotating shaft S) supported by the sealed bearing, such as idling stop vehicles, which have been increasing in recent years, frequently occurs. and the static friction coefficient between the seal sliding surface 11 and the starting torque of the sealed bearing can be reduced.

In addition, in this sealed bearing, the _ratio of the corner portions 12a and 12b to the height h1 of the projection ₁₂ is 30% or less. It is possible to form a sufficient wedge-shaped gap to maintain fluid lubrication between the top portion 12c of the projection 12 and the seal sliding surface 11 even when the rolling bearing 1 rotates at a low speed.

Further, in this sealed bearing, since the projection 12 has the corner portions 12a and 12b on both sides in the circumferential direction of the projection 12, the circumferential width W can be widened to both sides in the vicinity of the root of the projection 12 to improve the strength. .

In addition, since the corner portions 12a and 12b of this bearing with seal are formed over the entire length of the projection 12, the entire length of the projection 12 can be utilized without waste to improve the strength of the vicinity of the base of the projection 12. .

In addition, in this bearing with seal, the combined roughness σ of the projection 12 and the seal sliding surface 11 is 0.9 μm or less, so that the sliding portion of the projection 12 and the seal sliding surface 11 can be moved even at extremely low peripheral speeds. It is suitable for creating a fluid lubricating state in which no stick-slip phenomenon occurs.

In each of the above-described embodiments, an example in which the protrusions are evenly arranged in the circumferential direction has been shown, but it is also possible to arrange them non-uniformly.

Further, in each of the above-described embodiments, the seal member is composed of a metal core and a vulcanized rubber material, but the present invention is applicable to a seal member formed of a single material such as a rubber material or a resin material. It is also possible to

Moreover, although the radial lip is illustrated in each of the above-described embodiments, the present invention is applied to a seal lip (axial lip) that exhibits a sealing action with a seal sliding surface having a gradient exceeding 45° with respect to the axial direction. It is also possible to

In addition, in each of the above-described embodiments, an inner ring rotating radial ball bearing was exemplified, but the present invention can also be applied to an appropriate type such as an outer ring rotating bearing, a thrust bearing, or a roller bearing. Also, although an example in which the seal sliding surface is formed on the rotating ring has been shown, it is also possible to apply the present invention when forming the seal sliding surface on the stationary ring.

It should be considered that the embodiments disclosed this time are illustrative in all respects and not restrictive. Therefore, the scope of the present invention is indicated by the scope of the claims rather than the above description, and is intended to include all modifications within the meaning and scope of equivalents of the scope of the claims.

Reference Signs List 1 rolling bearing 2 seal member 7 internal space 10 seal lip 11 seal sliding surface 12 projections 12a, 12b corner portion 13 gap

Claims (5)

A seal member that seals the internal space of the rolling bearing from the outside, and a seal sliding surface that slides in the circumferential direction against the seal member,
The seal member has a seal lip formed in an annular shape, the seal lip has a plurality of projections arranged in a circumferential direction, and the plurality of projections extend between the circumferentially adjacent projections. A gap that communicates with the internal space and the outside is generated, and an oil film of lubricating oil that is dragged from the gap between the protrusion and the seal sliding surface as the bearing rotates creates a gap between the seal lip and the seal sliding surface. In a sealed bearing that is formed in a manner that can be in a fluid lubricated state,
The bearing with a seal, wherein the projection has a curved corner portion that gradually widens the circumferential width of the projection from the middle portion in the height direction of the projection to the root. 2. The bearing with seal according to claim 1, wherein the ratio of the corner portion to the height of the protrusion is 30% or less. 3. The sealed bearing according to claim 1, wherein the projection has the corner portions on both circumferential sides of the projection. The sealed bearing according to any one of claims 1 to 3, wherein the corner portion is formed over the entire length of the projection. 5. The bearing with seal according to claim 1, wherein a combined roughness σ of said projection and said seal sliding surface is 0.9 μm or less.

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