JP2021011896A - Beating with seal - Google Patents

Abstract

To improve foreign matter intrusion prevention property with a seal lip in a bearing with a seal which can make an interval between the seal lip and a seal slide surface into a fluid lubrication state by a plurality of projections of the seal lip.SOLUTION: A plurality of projections 5b, 5c form two or more rows of projections 5b, 5c arranged in a circumferential direction. The second row of projections 5c located on a bearing internal space side with respect to the first row of projections 5b are arranged so as to face a first gap g1 formed between the first row of projections 5b.SELECTED DRAWING: Figure 1

Description

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

For example, foreign matter such as gear wear powder is mixed in a transmission mounted on a vehicle such as an automobile or various construction machines. For this reason, the sealing member prevents foreign matter from entering the internal space of the bearing and prevents premature damage of the rolling bearing.

A general sealing member has a sealing lip made of a rubber-like material or the like. Bearing parts that rotate in the circumferential direction with respect to the seal member, such as the raceway ring and slinger, are formed with a seal sliding surface that allows the seal lip to slide and contact. Since the seal lip and the seal sliding surface slide into contact with each other over the entire circumference, the bearing torque increases due to the drag resistance (seal torque) of the seal lip. In addition, the friction of the sliding contact promotes the temperature rise of the rolling bearing. As this temperature rise progresses, an adsorption action is caused by the pressure difference between the bearing internal space and the outside, and the friction becomes large.

It is possible to eliminate the seal torque by arranging the seal lip of the seal member in non-contact with the bearing component to form a labyrinth seal, but the size of the gap between the seal member and the bearing component prevents foreign matter of a predetermined particle size from entering. It is difficult to manage various errors that can be prevented.

As a bearing with a seal that can significantly reduce the seal torque while being able to support high-speed operation of the bearing while preventing foreign matter of a predetermined particle size from entering, a large number of protrusions lined up in the circumferential direction are formed on the seal lip, and these protrusions and seal lubrication It has been proposed that the seal lip and the seal sliding surface are in a fluid-lubricated state due to the wedge effect when the lubricating oil is dragged from the gap between the moving surfaces (Patent Document 1).

JP-A-2017-155929

In the case of the sealed bearing proposed in Patent Document 1, foreign matter having a particle size smaller than a predetermined particle size passes through a gap communicating with the bearing internal space and the outside. For this reason, if the amount of small foreign matter mixed in the lubricating oil supplied from the outside is unexpectedly large, there is a concern that foreign matter origin type peeling may occur in the raceway ring and the rolling element, which adversely affects the bearing life.

In view of the above background, the problem to be solved by the present invention is a foreign matter due to the seal lip in a bearing with a seal capable of fluid-lubricating between the seal lip and the seal sliding surface by a plurality of protrusions of the seal lip. It is to improve the intrusion prevention property.

In order to achieve the above problems, the present invention presents a seal member that separates the bearing internal space and the outside, a seal lip provided on the seal member, and a seal sliding that slides in the circumferential direction with respect to the seal lip. The surface is provided with a plurality of protrusions formed on the seal lip so as to form a gap between the seal sliding surface and the seal lip, and the plurality of protrusions are formed from the inside of the gap as the bearing rotates. In a bearing with a seal, which is formed in such a manner that the seal lip and the seal sliding surface can be brought into a fluid-lubricated state by an oil film of lubricating oil dragged between the protrusion and the seal sliding surface. A plurality of protrusions form two or more rows of the protrusions arranged in the circumferential direction, and the second row of protrusions located on the bearing internal space side with respect to the first row of protrusions is the first row. A configuration is adopted in which the first gap formed between the protrusions of the row is arranged so as to face the first gap.

According to the above configuration, a gap is generated between the seal sliding surface and the seal lip due to a plurality of protrusions, and the lubricating oil in the gap is dragged between the seal sliding surface and the seal lip as the bearing rotates. It is possible to promote the formation of an oil film by the wedge effect and to make the seal lip and the seal sliding surface in a fluid lubricated state. The plurality of protrusions form two or more rows, and the protrusions in the first row and the protrusions in the second row located on the bearing internal space side with respect to the protrusions in the first row are included in the two rows. Exists. The lubricating oil supplied from the outside may contain small foreign substances that can pass through the first gap formed between the protrusions in the first row located on the outside side. The small foreign matter is flowed through the first gap to the bearing internal space side by the lubricating oil, but because there are protrusions in the second row facing the first gap, the small foreign matter moves the first gap to the bearing internal space side. It becomes difficult to pass through. In this way, the foreign matter intrusion prevention property by the seal lip is improved.

Specifically, the protrusion has a curved wedge surface that gradually becomes farther from the seal sliding surface from the central portion in the circumferential direction of the protrusion toward both sides in the circumferential direction, and the wedge surface in the protrusions in the first row. When the radius of curvature of is r1 and the radius of curvature of the wedge surface in the protrusions in the second row is r2, it is preferable that r1> r2. If the protrusion is a curved wedge surface as described above, it is possible to prevent the oil film from breaking due to the protrusion and promote the formation of the oil film. If the radius of curvature r2 of the wedge surface in the protrusions in the second row is made smaller than the radius of curvature r1 of the wedge surface in the protrusions in the first row, the seal sliding surface and the protrusions in the second row can be compared with each other. Since the gap between the wedge surfaces is narrowed, it is possible to further suppress the intrusion of foreign matter into the internal space of the bearing.

The circumferential width of the protrusions in the first row is w1, and among the protrusions in the second row, the protrusions in the second row gradually become farther from the seal sliding surface from the central portion in the circumferential direction toward both sides in the circumferential direction. When the circumferential width of the wedge surface is w2, it is preferable that w1> w2. By doing so, it is possible to suppress the intrusion of foreign matter while realizing low torque between the protrusions in the second row and the sliding surface of the seal.

More preferably, the total number of rows formed by the plurality of protrusions is two rows, and the first facing distance between the non-protrusion portion connected between the protrusions in the first row and the seal sliding surface is h1. When the second facing distance between the end of the protrusions in the second row facing the first gap and the sealing sliding surface is h2, it is said that h1> h2. By doing so, it is possible to further suppress the intrusion of foreign matter while reducing the torque by limiting the total number of rows of protrusions to the minimum two rows.

As described above, according to the present invention, by adopting the above configuration, in a bearing with a seal capable of fluid-lubricating between the seal lip and the seal sliding surface by a plurality of protrusions of the seal lip, foreign matter invades by the seal lip. The preventability can be improved.

Sectional drawing which shows the vicinity of the seal lip of the bearing with a seal which concerns on 1st Embodiment of this invention. Cross-sectional view of the bearing with seal according to the first embodiment Sectional view of line III-III of FIG. Sectional view of line IV-IV of FIG. Partial front view showing the seal member according to the first embodiment from the axial direction Enlarged view near the protrusion in FIG. A cross-sectional view showing the vicinity of the seal lip according to the second embodiment of the present invention with the same cut surface as in FIG. A cross-sectional view showing the vicinity of the seal lip according to the third embodiment of the present invention with the same cut surface as in FIG. A cross-sectional view showing the vicinity of the seal lip according to the fourth embodiment of the present invention with the same cut surface as in FIG. A cross-sectional view showing the vicinity of the seal lip according to the fourth embodiment with the same cut surface as in FIG.

Hereinafter, the bearing with a seal according to the first embodiment as an example of the present invention will be described with reference to FIGS. 1 to 6 of the attached drawings.

The sealed bearing shown in FIGS. 1 and 2 includes an inner ring 1, an outer ring 2, a plurality of rolling elements 4 held by a cage 3, and a bearing internal space 6 formed between the inner ring 1 and the outer ring 2. It includes two sealing members 5 that seal both ends.

The inner ring 1 and the outer ring 2 have a raceway surface corresponding to the rolling element 4. The inner ring 1 is attached to a rotating shaft (not shown) and rotates integrally with the rotating shaft. The rotating shaft is provided, for example, as a rotating portion of a vehicle transmission or differential. The outer ring 2 is attached to a member such as a housing or a gear that applies a load from the rotating shaft. A ball is adopted as the rolling element 4. This sealed bearing is a deep groove ball bearing.

An annular bearing internal space 6 is formed by the inner ring 1 and the outer ring 2. The seal member 5 separates the bearing internal space 6 and the outside. The plurality of rolling elements 4 revolve in the bearing internal space 6 while interposing between the inner ring 1 and the outer ring 2. The bearing internal space 6 is lubricated by lubricating oil supplied from the outside. An appropriate amount of grease may be sealed in the bearing internal space 6 as an initial lubricant.

In the following, the direction along the bearing central axis of the bearing with seal is referred to as "axial direction". The direction orthogonal to the axial direction is called the "diameter direction". The circumferential direction around the center axis of the bearing is called the "circumferential direction". In the illustrated example, the bearing central axis is the central axis of the inner ring 1 as the rotating wheel, and corresponds to the left-right direction in FIGS. 1 and 2.

A seal groove 2a for holding the seal member 5 is formed at the end of the inner circumference of the outer ring 2. The seal member 5 is attached to the outer ring 2 by press-fitting the outer peripheral edge thereof into the seal groove 2a.

On the outer side of the seal member 5 as a boundary, foreign matter such as gear wear powder, clutch wear powder, and fine crushed stones exists depending on the installation destination of the sealed bearing. Such powdery foreign matter can reach the vicinity of the sealing member 5 by the flow of lubricating oil or atmosphere. The seal member 5 is for suppressing foreign matter from entering the bearing internal space 6 from the outside.

The seal member 5 has a seal lip 5a protruding like a tongue piece on the inner peripheral side thereof. A seal sliding surface 1a that slides in the circumferential direction with respect to the seal lip 5a is formed on the outer periphery of the inner ring 1. The seal sliding surface 1a has a cylindrical surface shape that is continuous all around the circumferential direction.

FIG. 1 is an enlarged view of the vicinity of the seal lip 5a of the seal member 5 of FIG. A cross-sectional view taken along line III-III in FIG. 1 is shown in FIG. Further, a cross-sectional view of the IV-IV line in FIG. 1 is shown in FIG. FIG. 5 shows the outer shape of the seal member 5 when viewed in the axial direction from the bearing internal space side in a single and natural state. FIG. 6 is a remarkably enlarged view of the vicinity of the protrusion of FIG.

The seal lip 5a is a radial lip. Here, the radial lip is a seal sliding surface along the axial direction or a seal sliding surface having an acute-angled gradient within 45 ° with respect to the axial direction and a seal lip that exerts a sealing action. It has a radial tightening allowance between it and the moving surface.

As shown in FIG. 5, the seal lip 5a has a tip edge that defines the inner diameter of the seal lip 5a in a natural state. The seal lip 5a pressed in the radial direction against the seal sliding surface 1a by the tightening allowance set between the seal lip 5a and the seal sliding surface 1a is deformed in a rubber-like elasticity bent outward as shown in FIG. Produces a tense force of the seal lip 5a. The attachment error, manufacturing error, and the like of the seal member 5 are absorbed by the change in the bending condition of the seal lip 5a.

As shown in FIGS. 1, 3 and 4, the seal lip 5a has a plurality of protrusions 5b and 5c formed so as to form gaps g1 and g2 between the seal sliding surface 1a and the seal lip 5a.

The plurality of protrusions 5b and 5c have a seal lip 5a and a seal slide due to an oil film of lubricating oil (not shown) that is dragged between the protrusions 5b and 5c and the seal sliding surface 1a from within the gaps g1 and g2 as the bearing rotates. It is formed in such a manner that the space between the moving surfaces 1a can be in a fluid lubricated state.

The protrusions 5b and 5c have a protrusion height in the direction orthogonal to the seal sliding surface 1a, that is, in the normal direction perpendicular to the tangent line in contact with the seal sliding surface 1a. Since the seal sliding surface 1a has a cylindrical surface shape centered on the bearing central axis, the direction orthogonal to this corresponds to the radial direction.

The plurality of protrusions 5b and 5c are a row of protrusions 5b arranged in the circumferential direction (first row) and a row of protrusions 5c arranged in the circumferential direction at a position on the bearing internal space 6 side with respect to the protrusions 5b in the first row (first row). Two rows).

As shown in FIGS. 5 and 6, the protrusions 5b and 5c are wedge surfaces formed in a curved shape gradually becoming farther from the seal sliding surface 1a from the central portion in the circumferential direction of the protrusions 5b and 5c toward both sides in the circumferential direction. It has 5d and 5e.

The protrusions 5b and 5c extend in a direction orthogonal to the circumferential direction. The protrusions 5b and 5c are formed over the entire range having a radial tightening allowance between the protrusions 5b and 5c and the seal sliding surface 1a. The protrusion 5b located on the outermost side extends to the tip edge of the seal lip 5a.

In each row, the protrusions 5b and 5c are arranged at regular intervals in the circumferential direction. The protrusions 5b and 5c have the same shape, and the width, height, and the like in the circumferential direction are set to be the same in each row. Considering the appearance of FIG. 6, the protrusions 5b and 5c of each row appear in a radial pattern arranged in the circumferential direction at a constant pitch angle. The radiation center is on the central axis of the seal member 5 (corresponding to the bearing central axis).

As shown in FIGS. 3 and 4, the protrusion 5c in the second row has an end portion 5f facing the first gap g1 formed between the protrusions 5b in the first row. The direction in which the first gap g1 and the protrusion 5c in the second row face each other is a direction orthogonal to the circumferential direction and along the seal sliding surface 1a. In the illustrated example, since the seal sliding surface 1a has a cylindrical surface shape extending in the circumferential direction, as shown in FIGS. 1, 3, and 4, the protrusions 5c in the second row are in the axial direction with the first gap g1. Facing.

As shown in FIG. 2, the sealing member 5 is formed of a metal plate core metal 5 g and a vulcanized rubber material 5 h adhering to at least the inner diameter portion of the core metal 5 g. The seal lip 5a is formed of a vulcanized rubber material 5h in the shape of a tongue piece protruding from the core metal 5g toward the seal sliding surface 1a. The core metal 5 g is a pressed part formed in an annular shape that is continuous in the circumferential direction. The vulcanized rubber material 5h is a vulcanized rubber portion.

As shown in FIG. 6, the wedge surface 5d of the protrusion 5b in the first row and the wedge surface 5e of the protrusion 5c in the second row are formed in a semi-cylindrical surface shape over the entire length of the protrusions 5b and 5c in the radial direction. There is. When the seal member 5 is attached in a predetermined manner as shown in FIG. 2, the wedge surfaces 5d and 5e are pressed against the seal sliding surface 1a by the tense force of the seal lip 5a, so that the central portion of the protrusions 5b and 5c in the circumferential direction is shown in FIG. Elastic deformation occurs so that it is slightly crushed.

Since the protrusions 5b and 5c extend in a direction orthogonal to the circumferential direction and have the above-mentioned wedge surfaces 5d and 5e, the protrusions 5b and 5c while suppressing the area where the protrusions 5b and 5c and the seal sliding surface 1a can be in sliding contact with each other are suppressed. Avoiding sharpening of the central part in the circumferential direction of 5c, preventing oil film breakage due to protrusions 5b and 5c, increasing oil pressure by the wedge effect to promote oil film formation, and fluid lubrication between the seal lip 5a and the seal sliding surface 1a. Can be in a state. Further, even if the protrusions 5b and 5c are rubbed against the seal sliding surface 1a when the seal member 5 is attached, there is no concern that the protrusions 5b and 5c are bent in the circumferential direction, and the seal torque reduction performance may be impaired during the attachment. There is no.

When the seal member 5 is attached, the protrusions 5b and 5c that come into contact with the seal sliding surface 1a stretch against the tense force of the seal lip 5a, so that the protrusions 5b and 5c in each row are separated from each other in FIGS. , As shown in FIG. 4, gaps g1 and g2 are formed between the seal sliding surface 1a and the seal sliding surface 1a. The first gap g1 generated between the protrusions 5b in the first row located on the outermost side is open to the outside. The second gap g2 generated between the protrusions 5c in the second row located most on the bearing internal space 6 side is open to the bearing internal space 6. The seal lip 5a can make sliding contact with the seal sliding surface 1a only on the protrusions 5b and 5c.

As shown in FIG. 3, a space for communicating the first gap g1 and the second gap g2 is formed between the protrusion 5b in the first row and the protrusion 5c in the second row closest to the protrusion 5b. There is. The first gap g1 and the second gap g2 are axially communicated with each other in a wedge-shaped space. Therefore, the lubricating oil can enter and exit the bearing internal space and the outside through the communication space between the first gap g1 and the second gap g2. The flow path cross-sectional area of the communication space between the first gap g1 and the second gap g2 is smaller than the flow path cross-sectional area of the first gap g1. In the illustrated example, the circumferential width of the communication space is the circumferential direction of the first gap g1 (the distance between the protrusions 5b adjacent to each other in the circumferential direction, and the circumferential length of the non-protrusion portion connected between the protrusions 5b). It is less than half the width. Further, the radial width of the communication space is less than half of the facing distance between the non-projection portion between the protrusions 5b adjacent to each other in the circumferential direction and the seal sliding surface 1a.

Even if a small foreign matter c that can pass through the first gap g1 enters the first gap g1 along with the flow of the lubricating oil, it is difficult for the small foreign matter c to pass through the narrow above-mentioned communication space and can escape to the second gap g2. It is suppressed. Further, when the foreign matter c that has entered the first gap g1 cannot escape to the second gap g2, the lubricating oil that hits the end portion 5f of the protrusion 5c in the second row and bounces off as shown by the arrow in FIG. It will be discharged to the outside by the flow of the lubricating oil and the flow of the lubricating oil discharged to the outside from the bearing internal space side. In this way, even if the small foreign matter c mixed in the lubricating oil is flown into the first gap g1 on the outer side shown in FIGS. 1, 3, and 4, the protrusions in the second row facing the first gap g1. Since there is 5c, it becomes difficult for the small foreign matter c to pass through the first gap g1 toward the bearing internal space side. In this way, the foreign matter intrusion prevention property by the seal lip is improved.

For example, in an application for supporting a rotating portion in a vehicle transmission, the sealed bearing is generally lubricated by an appropriate method such as splashing or oil bathing. Therefore, the lubricating oil supplied from the outside exists around the seal lip 5a of the seal member 5 of FIG. The lubricating oil is also commonly used in other lubricating parts such as gears existing 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 substance having a particle size of more than 0.05 mm enters the bearing internal space 6, it is considered that the bearing life is adversely affected. If the height of the protrusions 5b in the first row in FIG. 3 is set to 0.07 mm or less, gaps g1 and g2 through which such a large foreign matter cannot easily pass are created between the seal lip 5a and the seal sliding surface 1a. be able to. When the heights of the protrusions 5b and 5c are 0.07 mm or less, for example, the distance between the protrusions 5b and 5c adjacent to each other in the circumferential direction in each row is 0.3 mm or more and 2.6 mm or less, and the circumferential width of the protrusions 5b and 5c. Can be set in the range of 0.2 mm or more and 1.0 mm or less, and the radius of curvature of the wedge surfaces 5d and 5e is 0.15 mm or more and less than 2.0 mm. In this range, the CVTF that lubricates the pulley and belt of the CVT as lubricating oil, the oil temperature is 30 to 120 ° C., and the speed at which the seal sliding surface 1a rotates relative to the seal lip 5a in the circumferential direction (peripheral speed). When is 0.2 m / s or more, the viscosity-rigid region (RI mode) or the isobaric region (RI mode) in the lubrication region diagram based on the viscosity parameter gv and the elasticity parameter g, which are non-dimensional numbers determined by Greenwood-Johnson in calculation. It is distributed in any of the lubrication modes of the isoviscosity-elastic body region (EI mode, soft EHL), that is, the space between the seal lip 5a including the protrusions 5b and 5c and the seal sliding surface 1a is completely covered with an oil film. It is considered to be in a separated fluid lubrication state. When the fluid lubrication state is reached, the seal torque by the seal member 5 can be reduced to the same level as that of the non-contact type seal, the temperature rise of the bearing with the seal can be suppressed, and the adsorption action of the seal lip 5a can be prevented.

When the distance between the protrusions 5b and 5c in each row is 2.6 mm, an oil film of about 3 μm (maximum of the seal sliding surface 1a) is calculated between the protrusions 5b and 5c and the seal sliding surface 1a. The height roughness Rz is exceeded by a margin), and when it is smaller than 2.6 mm, the oil film tends to be thick. Further, when it is 2.6 mm or less, the bearing rotation torque tends to decrease (that is, the seal torque tends to decrease). If the distance between the protrusions 5b and 5c in each row is less than 0.3 mm, it becomes difficult to mold the seal lip 5a with a mold. Considering molding with a mold, it is preferable to set the radius of curvature of the wedge surfaces 5d and 5e to 0.15 mm or more and less than 2.0 mm. Since the circumferential width of the protrusions 5b and 5c depends on the radius of curvature of the corresponding wedge surfaces 5d and 5e, it is preferable to set the circumferential width of the protrusions 5b and 5c to 0.2 mm or more and 1.0 mm or less.

As described above, in the bearings with seals shown in FIGS. 1 to 6, the seal lip 5a and the seal sliding surface 1a can be lubricated by a plurality of protrusions 5b and 5c of the seal lip 5a. The plurality of protrusions 5b and 5c are arranged in two or more rows in the circumferential direction, and the protrusions 5b and 5c are located on the bearing internal space 6 side with respect to the first row of protrusions 5b. Since the protrusions 6c in the second row are arranged so as to face the first gap g1 formed between the protrusions 5b in the first row, they are smaller than the conventional example in which a plurality of protrusions are arranged in a row. It becomes difficult for foreign matter to pass through the first gap g1 toward the bearing internal space 6, which makes it possible to improve the foreign matter intrusion prevention property by the seal lip 5a, which in turn makes it possible to improve the foreign matter intrusion prevention point in the inner / outer rings 1 and 2 and the rolling element 4. It is possible to suppress the occurrence of mold peeling and extend the life of the sealed bearing.

As a result, the protrusion 5c in the second row also suppresses the external lubricating oil from reaching the bearing internal space 6, but the lubrication between the protrusion 5c in the second row and the seal sliding surface 1a is , It is possible to sufficiently secure the lubricating oil supplied from the outside and the lubricating oil in the bearing internal space 6. Further, the protrusions 5c in the second row are also effective in suppressing the excessive supply of lubricating oil from the outside to the bearing internal space 6, so that the stirring resistance in the bearing internal space 6 can be reduced. This is advantageous, for example, in reducing the loss of the entire transmission.

In the first embodiment, the protrusion 5b in the first row and the protrusion 5c in the second row have the same shape, but they may have different shapes. A second embodiment as an example thereof is shown in FIG. In the following, only the differences from the first embodiment will be described, and the same reference numerals will be used for the corresponding components.

In the second embodiment, when the radius of curvature of the wedge surface 5d in the protrusion 5b of the first row is r1 and the radius of curvature of the wedge surface 5e in the protrusion 5c of the second row is r2, the second row in the second embodiment. The protrusion 5c of the above is r1> r2. The wedge surface 5e of the protrusion 5c has a substantially semi-cylindrical shape in which the curvature at the central portion in the circumferential direction is relaxed in order to make r1> r2. The area of the end portion 5f of the protrusion 5c in the second row is larger than that in the first embodiment, and the seal sliding surface 1a and the second row are larger than those in the first embodiment in which r1 = r2. The gap between the wedge surfaces 5e of the protrusions 5c will be narrowed. Therefore, in the bearing with a seal according to the second embodiment, the communication space between the first gap g1 and the second gap g2 is narrower than that in the first embodiment, so that foreign matter can be further suppressed from entering the bearing internal space. it can.

In each of the above-described embodiments, the case where the total number of rows of the plurality of protrusions 5b and 5c is two is illustrated, but the total number of rows may be three or more. In this case, between the adjacent rows, the protrusions of the adjacent rows on the bearing internal space side may face each other with respect to the gap between the protrusions of the rows located on the outer side. A third embodiment as an example thereof is shown in FIG.

In the third embodiment, a plurality of protrusions 5b, 5c, 5i form three rows. The protrusions 5i in the third row located on the bearing internal space side (left side in the drawing) with respect to the protrusions 5b in the second row are arranged so as to face the second gap g2 formed between the protrusions 5b in the second row. Has been done. The protrusions 5i in the third row have the same shape as the protrusions 5b in the second row. The third gap g3 formed between the protrusions 5i in the third row adjacent to each other in the circumferential direction communicates with the second gap g2. Therefore, the lubricating oil can flow between the inner space of the bearing and the outer space, but the communication space thereof is as narrow as the communication space of the first gap g1 and the second gap g2.

In the third embodiment, even if a small foreign matter that has entered the first gap g1 escapes to the second gap g2, the protrusion 5i in the third row faces the second gap g2, so that the second The bearing internal space cannot be reached unless the narrow communication space between the gap g2 and the third gap g3 is passed through. Therefore, according to the third embodiment, the foreign matter intrusion prevention property by the seal lip 5a can be improved as compared with the first and second embodiments.

As the total number of rows of the plurality of protrusions 5b, 5c, 5i increases, the shear resistance of the lubricating oil dragged between the protrusions 5b, 5c, 5i and the seal sliding surface increases. Therefore, when low torque is important, the total number of rows is preferably two, and when foreign matter intrusion prevention is important, the total number of rows is preferably three or more.

In each of the above embodiments, the case where the wedge surface 5e of the protrusion 5c in the second row covers the entire width of the circumferential width of the protrusion 5c is illustrated, but the wedge surface 5e of the protrusion 5c in the second row is the circumferential width of the protrusion 5c. It may have a smaller circumferential width. A fourth embodiment as an example thereof is shown in FIGS. 9 and 10.

The protrusions 5c in the second row of the fourth embodiment project in a two-step step shape toward the seal sliding surface 1a, and have a wedge surface 5e only on the step side close to the seal sliding surface 1a. It has become.

Here, the circumferential width of the protrusions 5b in the first row is w1, and the circumferential width of the wedge surface 5e of the protrusions 5c in the second row is w2. Further, the first facing distance between the non-projection portion, which is the seal lip portion connected between the protrusions 5b in the first row, and the seal sliding surface 1a is set to h1. Further, the second facing distance between the end portion 5f facing the first gap g1 of the protrusions 5c in the second row and the seal sliding surface 1a is set to h2.

The protrusions 5c in the second row extend along the circumferential direction from both ends in the circumferential direction of the wedge surface 5e. Therefore, the circumferential width of the protrusions 5c in the second row is larger than the circumferential width w2 of the wedge surface 5e, and is between the step side of the protrusions 5c far from the seal sliding surface 1a and the seal sliding surface 1a. A second facing interval h2 is formed in.

The circumferential width w1 of the protrusions 5b in the first row> the circumferential width w2 of the wedge surface 5e of the protrusions 5c in the second row.

The first facing interval h1 corresponds to the radial width of the first gap g1. The first facing distance h1> the second facing distance h2.

The radius of curvature r2 of the protrusions 5c in the second row is smaller than the radius of curvature r1 of the protrusions 5b of the first row. Further, the total number of rows formed by the plurality of protrusions 5b and 5c is two rows.

According to the fourth embodiment, since the circumferential width w2 of the wedge surface 5e of the protrusions 5c in the second row is smaller than the circumferential width w1 of the protrusions 5b in the first row, w1 = w2. Compared to the embodiment, the protrusion 5c in the second row suppresses the intrusion of foreign matter while suppressing the shear resistance and friction of the lubricating oil between the protrusion 5c in the second row and the sealing sliding surface 1a to reduce the torque. can do.

Further, according to the fourth embodiment, the second facing distance h2 between the end portion 5f of the protrusion 5c in the second row and the seal sliding surface 1a is a non-protrusion portion connected between the protrusions 5b in the first row. Since it is smaller than the first facing distance h1 with the seal sliding surface 1a, it is compared with the case where a relatively narrow second row protrusion corresponding to the circumferential width w2 of the second row protrusion is adopted. , The circumferential width of the protrusions 5c in the second row is expanded beyond the circumferential width w2 of the wedge surface 5e to expand the area of the end portion 5f and narrow the communication space between the first gap g1 and the second gap g2. However, the invasion of foreign matter can be further suppressed.

As described above, according to the fourth embodiment, the total number of rows formed by the plurality of protrusions 5b and 5c is limited to the minimum two rows, the radius of curvature r2 <the radius of curvature r1 described above, and the second By setting the circumferential width w2 of the wedge surface 5e of the protrusions 5c in the row <the circumferential width w1 of the protrusions 5b in the first row, it is possible to reduce the torque particularly while suppressing the intrusion of foreign matter.

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

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

Further, in each of the above-described embodiments, the radial ball bearing of the inner ring rotation has been exemplified, but the present invention can also be applied to the outer ring rotation, the thrust bearing, and the roller bearing.

The embodiments and examples disclosed this time should be considered to be exemplary in all respects and not restrictive. Therefore, the scope of the present invention is shown not by the above description but by the scope of claims, and it is intended that all modifications within the meaning and scope equivalent to the scope of claims are included.

1a Seal sliding surface 5 Seal member 5a Seal lip 5b, 5c, 5i Protrusion 6 Bearing internal space

Claims (4)

A seal member that separates the internal space of the bearing and the outside,
The seal lip provided on the seal member and
A seal sliding surface that slides in the circumferential direction with respect to the seal lip,
A plurality of protrusions formed on the seal lip so as to create a gap between the seal sliding surface and the seal lip are provided.
The plurality of protrusions are brought into a fluid-lubricated state between the seal lip and the seal sliding surface by an oil film of lubricating oil that is dragged from the gap into the gap between the protrusion and the seal sliding surface as the bearing rotates. In a sealed bearing that is formed in a manner that allows
The plurality of protrusions form two or more rows of the protrusions arranged in the circumferential direction.
The protrusions in the second row located on the bearing internal space side with respect to the protrusions in the first row are arranged so as to face the first gap generated between the protrusions in the first row. A characteristic bearing with a seal. The protrusion has a curved wedge surface that gradually becomes farther from the seal sliding surface from the central portion of the protrusion in the circumferential direction toward both sides in the circumferential direction.
The sealed bearing according to claim 1, wherein when the radius of curvature of the wedge surface in the protrusions in the first row is r1 and the radius of curvature of the wedge surface in the protrusions in the second row is r2, r1> r2. .. The circumferential width of the protrusions in the first row is w1, and among the protrusions in the second row, the protrusions in the second row gradually become farther from the seal sliding surface from the central portion in the circumferential direction toward both sides in the circumferential direction. The sealed bearing according to claim 1 or 2, wherein w1> w2 when the circumferential width of the wedge surface is w2. The total number of rows formed by the plurality of protrusions is two rows.
The first facing distance between the non-protruding portion connected between the protrusions in the first row and the sliding surface of the seal is h1, and the end portion of the protrusions in the second row facing the first gap. The bearing with a seal according to claim 3, wherein h1> h2, where h2 is the second facing distance between the bearing and the seal sliding surface.

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