JP2005090527A - Sealing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealing device capable of achieving excellent sealing performance in severe conditions such as possible exposure to mass quantity of mud water, and achieving long service life. <P>SOLUTION: This sealing device is provided with a side lip (seal lip) 12 fixed in a sealing way to a housing (one member) 1, with a tip slidably and tightly applied to an end surface 22a of a slinger (the other member) 20 installed on a rotation shaft 2. In a back surface 12b of the slide lip 12 to be set back-to-back to the slider 20, a plurality of fins 15 are formed to extend at a prescribed angle to a rotation direction. As liquid flows toward the back surface 12b of the slide lip 12, flow of liquid in accordance with rotation is converted into pressure of the side lip 12 by means of the fins 15. Tight contact surface pressure to the slinger 20 is thus increased, and excellent sealing performance is achieved. In case there is no liquid flowing toward the back surface 12b, tight contact surface pressure of the side lip 12 is small, so that abrasion due to sliding is restricted. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a sealing device used as a sealing means for a bearing portion of a suspension device of a vehicle and other rotating parts of a general-purpose machine.

A typical prior art of a sealing device used in a bearing unit that rotatably supports a wheel on a suspension device in a vehicle is described in, for example, Patent Document 1 below.
Japanese Patent Laid-Open No. 09-287619 (FIG. 2)

  FIG. 9 is a partial cross-sectional view showing the sealing device 120 described in Patent Document 1 by cutting along a plane passing through its axis. In FIG. 9, reference numeral 100 denotes a hub in which the outer ring 100 is a hub to which a center shaft portion 112 is inserted into the outer ring 4 and a wheel (not shown) is attached in the flange portion 111, and is arranged on the right side in FIG. A plurality of spheres (not shown) are held between a raceway formed on the outer peripheral surface of the central shaft portion 112 and a raceway formed on the inner peripheral surface of the outer ring 100 so as to freely roll. The central shaft portion 112, the outer ring 100, and the sphere of the hub 110 constitute a bearing unit. A sealing device 120 is interposed between the inner peripheral surface of the outer end portion of the outer ring 100 and the outer peripheral surface of the central shaft portion 112 of the hub 110, and rainwater, mud water or In addition to preventing foreign matter such as dust from entering, grease filled in the bearing internal space S where the spheres are present is prevented from leaking to the outside.

  The sealing device 120 includes a metal outer ring 121 press-fitted to the inner peripheral surface of the outer ring 100, side lips 122 and 123, and a radial lip 124. The side lips 122 and 123 and the radial lip 124 are made of a rubber-like elastic material, and are integrally vulcanized and bonded to the outer ring 121 through a common base 125. The outer side lip 122 extends so as to open to the opposite side of the bearing inner space S, and its tip is in close contact with the end surface of the flange portion 111 of the hub 110 so as to be slidable. Is extended so as to open to the opposite side to the bearing internal space S, and the tip thereof is slidably in contact with the curved surface portion 113 between the flange portion 111 and the central shaft portion 112 of the hub 110, and further, The peripheral radial lip 124 is in close contact with the outer peripheral surface of the central shaft portion 112 of the hub 110 so that the tip end facing the bearing internal space S side is slidable.

  Such a sealing device 120 is used under severe conditions in which muddy water flows from the gap G between the flange portion 111 of the hub 110 and the outer ring 100 when the vehicle travels in rainy weather. In order to improve, the surface pressure of the side lips 122 and 123 with respect to the hub 110 is increased. However, when the surface pressure of the side lips 122 and 123 is increased, the sliding load increases, and the sealing performance is deteriorated at an early stage due to wear, and the side lips 122 and 123 are liable to be loosened (stress relaxation). Thus, there is a problem that the life of the sealing device 120 is shortened.

  The present invention has been made in view of the above problems, and its technical problem is to exhibit excellent sealing performance under a severe condition such as being exposed to a large amount of muddy water, and to extend the service life. An object of the present invention is to provide a sealing device that can be realized.

  As means for effectively solving the technical problem described above, the sealing device according to the invention of claim 1 is hermetically fixed to one member of two members that are arranged substantially concentrically and relatively rotate. A seal lip whose tip is slidably in contact with the other member, and a plurality of surfaces extending opposite the rotation direction R at a predetermined angle α on a surface opposite to the other member of the seal lip. A fin is formed.

  According to a second aspect of the present invention, there is provided the sealing device according to the first aspect, wherein the seal lip has an open shape such that the tip thereof has a relatively large diameter, and forms a predetermined angle with the shaft center. Close to the face.

  According to a third aspect of the present invention, in the configuration according to the first or second aspect, the height h and the width w of the fin are increased at a portion near the tip.

  According to the sealing device of the first aspect of the present invention, when the liquid flows into the surface opposite to the other member of the seal lip, the fluid flow accompanying the rotation causes the dynamic pressure to be the pressing force of the seal lip by the fin. The tight contact pressure is increased, and the liquid has excellent sealing performance. In a normal state where no liquid is present on the back surface, the contact surface pressure of the seal lip with respect to the other member is small, so that wear of the seal lip due to sliding is small, and an excellent sealing function is maintained over a long period of time.

  According to the sealing device of the second aspect of the present invention, the seal lip is an end face seal type that is in close contact with a surface that forms a predetermined angle with the shaft center. The contact surface pressure of the seal lip with respect to the member depends only on the reaction force due to bending deformation at the time of mounting, and the contact surface pressure and wear of the seal lip can be suppressed to be extremely small.

  According to the sealing device of the invention of claim 3, by increasing the height h and width w of the fin at the portion near the tip, the dynamic pressure is applied to the liquid that enters the narrow passage between the fins as it rotates. Since it occurs, the effect of increasing the close contact pressure of the seal lip when the liquid flows in can be further improved.

  Hereinafter, preferred embodiments of a sealing device according to the present invention will be described with reference to the drawings. FIG. 1 is a partial cross-sectional view showing a sealing device 3 according to the first embodiment by cutting along a plane passing through its axis, FIG. 2 is a partial cross-sectional view in the same mounting state, and FIG. 3 is FIGS. 4 is a developed view showing the back surface 12b of the side lip 12, FIG. 4 is a partial cross-sectional view showing the cross-sectional shape of the fin 15 cut along the line III-III in FIG. 3, and FIG. 5 is cut along the line III-III in FIG. It is a fragmentary sectional view showing other section shape of fin 15 which was done.

  First, in FIGS. 1 and 2, reference numeral 1 is a housing of a shaft seal portion of a rotating device, and reference numeral 2 is a rotating shaft that is supported substantially concentrically and rotatably on the inner periphery of the housing 1. The housing 1 corresponds to “one member” recited in claim 1.

  The sealing device 3 according to the first embodiment prevents fluid from flowing into the left space S2 in FIGS. 1 and 2 from the right space S1 in FIGS. 1 and 2 between the housing 1 and the rotating shaft 2. The sealing device main body 10 and the slinger 20 are included. Specifically, the sealing device body 10 includes an outer ring 11 that is closely fitted and fixed to the housing 1 side, and a side lip 12 and a radial lip 13 that are integrally provided on the outer ring 11.

  The outer ring 11 in the sealing device main body 10 is formed by stamping and pressing a metal plate such as a steel plate, and is press-fitted into the inner peripheral surface 1a of the housing 1 with a predetermined fastening allowance a shown in FIGS. It consists of a fitting cylinder part 11a that is tightly fitted, and an inward flange part 11b that extends from one end on the space S2 side to the inner peripheral side. Further, the side lip 12 and the radial lip 13 are made of a rubber-like elastic material and have a common base portion 14, and the base portion 14 extends from the inner peripheral portion of the inward flange portion 11 b of the outer ring 11. It extends so as to cover the inner peripheral surface of the fitting cylinder portion 11 a via the inner surface, and is integrated with the outer ring 11.

  That is, the sealing device main body 10 positions and sets an outer ring 11 previously coated with a vulcanizing adhesive in a predetermined mold (not shown), and between the outer ring 11 and the inner surface of the mold when the mold is closed. In the annular cavity defined in the above, the unvulcanized rubber material for molding is filled and heated and pressurized, so that the base 14 is removed simultaneously with the vulcanization molding of the side lip 12, the radial lip 13 and the base 14. The ring 11 is integrally vulcanized and bonded.

  The slinger 20 corresponds to the “other member” described in claim 1, and is manufactured by punching and pressing a metal plate such as a steel plate, and the outer peripheral surface of the rotating shaft 2 with a predetermined allowance. The sleeve portion 21 is press-fitted in close contact with 2a, and the flange portion 22 is expanded from the end on the space S1 side to the outer peripheral side in a plane perpendicular to the axis. The outer diameter of the flange portion 22 is smaller than the inner peripheral surface of the rubber layer 14a (a part of the base portion 14) attached to the fitting cylinder portion 11a of the outer ring 11 in the sealing device body 10, and therefore, FIG. In the mounted state, an annular gap G is formed between them.

  The side lip 12 in the sealing device main body 10 corresponds to the “seal lip” described in claim 1, and extends from the position near the inner periphery of the base portion 14 toward the space S <b> 1, and the tip is relative to the side lip 12. It is formed in an open conical shape so as to have a large diameter. The side lip 12 is slidably in contact with the end surface 22a of the flange portion 22 of the slinger 20 in a state in which the side lip 12 is bent so as to open further to the outer peripheral side from the unmounted state shown in FIG. Is. The end surface 22a of the flange portion 22 has a planar shape that is substantially orthogonal to the axis, and corresponds to a “surface that forms a predetermined angle with the axis”.

  A large number of fins 15 extending obliquely with respect to the rotation direction R of the slinger 20 (rotating shaft 2) are provided at predetermined intervals in the circumferential direction on the back surface 12b opposite to the end surface 22a of the flange portion 22 of the slinger 20 in the side lip 12. It is formed with. The back surface 12b corresponds to the “surface opposite to the other member” recited in claim 1.

Specifically, as shown in FIG. 3, a plurality of (three in the illustrated example) fins 15 ₁ to 15 ₃ extending in parallel with each other at an angle α with respect to the rotation direction R of the slinger (rotating shaft). The first group 15A and the fins 15 ₁ to 15 ₃ of the first group 15A are parallel to each other at an angle α to the opposite side with respect to the rotation direction R (three in the illustrated example). The second groups 15B composed of the fins 15 ₄ to 15 ₆ are alternately provided. In this case, the angle α is 0 degree ≦ α <90 degrees. Further, the fin 15 ₁ is located in the forefront with respect to the rotational direction R in the first group 15A, the distal end portion 15a between the fins 15 ₆ positioned last stage with respect to the rotational direction R in the second group 15B, and (or) first The fins 15 ₃ positioned at the last stage in the rotation direction R in the group 15A and the rear end portions 15b of the fins 15 ₄ positioned in the front stage in the rotation direction R in the second group 15B may be continuous with each other. .

  The angle β formed by the both side surfaces of the fin 15 with respect to the surface perpendicular to the back surface 12b of the side lip 12 is preferably 0 ° <β <90 °, that is, the cross-sectional shape of the fin 15 is shown in FIG. Such a mountain shape or a trapezoidal shape as shown in FIG. 5 is preferable. Further, the height h (see FIG. 4) and the width w (see FIG. 3) of the fins 15 are uniform.

  Returning to FIG. 1 and FIG. 2, the radial lip 13 in the sealing device main body 10 is located on the inner peripheral side of the side lip 12 and is formed to project from the inner peripheral portion of the base portion 14 toward the space S <b> 1. Yes. The inner diameter of the seal edge portion 13a on the inner periphery of the distal end of the radial lip 13 is smaller than the outer diameter of the sleeve portion 21 of the slinger 20 in the unmounted state shown in FIG. 1, that is, the outer peripheral surface of the sleeve portion 21. 21a is slidably in close contact with a tightening margin b.

  In the sealing device 3 according to the first embodiment having the above configuration, the sealing device main body 10 is hermetically fixed to the inner peripheral surface 1a of the housing 1 at the fitting cylindrical portion 11a of the outer ring 11, and this sealing device main body 10 The side lip 12 and the radial lip 13 in FIG. 3 are in close contact with the end surface 22a of the flange portion 22 of the slinger 20 and the outer peripheral surface 21a of the sleeve portion 21 that rotate integrally with the rotary shaft 2, so that the space S1 side This prevents fluid from flowing into the space S2.

  Since the flange portion 22 of the slinger 20 applies a centrifugal force to the fluid in contact with the fluid, the fluid to be sealed that attempts to intervene in the sliding portion between the side lip 12 and the flange portion 22 of the slinger 20 from the space S1 side. Are swung off by the centrifugal force and removed to the outer peripheral side.

  The contact force of the side lip 12 with respect to the flange portion 22 of the slinger 20 is a reaction force against bending deformation from the unmounted state shown in FIG. 1 to the mounted state shown in FIG. 2 when the rotating shaft 2 (slinger 20) is stopped. It depends only on. Further, even when the rotary shaft 2 (slinger 20) is rotating, the liquid is not present on the back surface 12b of the side lip 12, in other words, the base 14, the side lip 12 and the base 14 in the sealing device body 10 are surrounded. In a normal state in which no liquid flows into the space S3, the contact force of the side lip 12 with respect to the flange portion 22 of the slinger 20 is substantially dependent only on the reaction force. For this reason, the contact surface pressure of the front end portion 12a of the side lip 12 is normally kept small.

  Here, for some reason, liquid such as muddy water from the side of the space S1 passes through the gap G between the fitting cylindrical portion 11a of the outer ring 11 and the outer peripheral edge of the flange portion 22 of the slinger 20 in the sealing device body 10. Consider the case of flowing into a space S3 surrounded by 12 and the base 14.

First, since the liquid that has flowed into the space S3 is rotated by contact with the flange portion 22 of the rotating slinger 20, this liquid flow F is generated as a side lip as shown in FIGS. 12, it collides with a large number of fins 15 formed on the back surface 12 b of the twelve, and the dynamic pressure generated at this time acts as a pressing force against the side lip 12. Will increase. Moreover, as shown in FIG. 3, the fins 15 ₁ to 15 ₃ of the first group 15A with the tip 15a extending in the rotation direction R side generate a pumping force that pushes the liquid flowing in the rotation direction R toward the outer peripheral side. Therefore, the reaction force also acts in the increasing direction of the close contact pressure P. Furthermore, the fins 15 ₁ and the fin 15 ₆ the tip 15a to each other successive closely facing or to each other, even dynamic pressure by blocking the action to the flow of liquid to be moved to the outer peripheral side by centrifugal force, the pressing force of the side lip 12 Acts as

  Therefore, when the liquid flows into the space S3 surrounded by the side lip 12 and the base portion 14, the close contact pressure P of the front end portion 12a of the side lip 12 with respect to the flange portion 22 of the slinger 20 is caused by the above-described action. Increases and has an excellent sealing effect on the liquid flowing into the space S3. As described above, the contact surface pressure P is small in a normal operation state where no liquid exists in the space S3, and the contact surface pressure P increases only when the liquid flows into the space S3. Wear of the side lip 12 due to sliding is small, and an excellent sealing function is maintained over a long period of time.

  Further, even if a small amount of liquid passes through the sliding portion between the side lip 12 and the flange portion 22 of the slinger 20 toward the inner peripheral side, the leaked liquid travels along the tapered inner peripheral surface 12 c of the side lip 12. Since it flows into the radial lip 13 side and is sealed at the sliding portion between the radial lip 13 and the sleeve portion 21 of the slinger 20, the flange portion 22 and the side lip 12 are eventually swung by the swinging action of the flange portion 22 of the slinger 20. Are pushed back to the sliding portion and further discharged from the outer periphery to the space S1 side.

  As described above, the angle α formed by the fins 15 with respect to the rotation direction R shown in FIG. 3 may be 0 ° ≦ α <90 °, that is, 0 °. 6A and 6B are explanatory views showing a second embodiment of the present invention in which α = 0 degrees. FIG. 6A is a development view of the back surface 12b of the side lip 12, and FIG. It is B sectional drawing.

  That is, in this embodiment, a plurality of fins 15 extending in the circumferential direction are formed on the back surface 12 b of the side lip 12. Also in this case, the cross-sectional shape of the fin 15 may be a mountain shape as shown in FIG. 6B or a trapezoidal shape as shown in FIG. The angle β formed with respect to the plane perpendicular to 12b is preferably 0 ° <β <90 °.

  According to this form, when the liquid flows into the outer peripheral space S3 of the side lip 12, that is, when the back surface 12b side of the side lip 12 is in a liquid atmosphere, the liquid contacts the flange portion 22 of the rotating slinger 20. Since the centrifugal force CF is applied by the pressure and the flow F toward the outer circumferential side is generated along the back surface 12b of the side lip 12, the hydraulic fluid generated at this time collides with the plurality of fins 15 extending in the circumferential direction. However, it acts on the back surface 12 b of the side lip 12 as a pressing force that increases the close contact pressure P against the flange portion 22. Therefore, the close contact pressure P of the front end portion 12a of the side lip 12 with respect to the flange portion 22 of the slinger 20 increases, and an excellent sealing effect is exerted on the liquid flowing into the space S3.

  Next, FIG. 7 is explanatory drawing which shows the 3rd form in this invention, (A) is an expanded view of the back surface 12b of the side lip 12, (B) is BB sectional drawing in (A). In this embodiment, the protruding height h and width w of each fin 15 formed on the back surface 12b of the side lip 12 are gradually changed so as to increase at the portion 15c near the tip (near the outer periphery of the back surface 12b). It is.

As in FIG. 3, the fins 15 are arranged in parallel with each other at an angle α (0 degree ≦ α <90 degrees) with respect to the rotation direction R of the slinger (rotating shaft) (three in the illustrated example). a first group 15A consisting of the fin ₁₅ 1-15 _3), the opposite side with respect to the rotational direction R from the fins ₁₅ 1-15 ₃ of the first group 15A, the plurality extending parallel to one another at an angle α The second group 15B composed of the fins 15 ₄ to 15 ₆ (three in the illustrated example) is provided alternately. Also in this embodiment, in the fin 15 _first rotational direction leading stage in one group 15A, the distal end portion 15a between the fins 15 ₆ in the rotational direction last stage of the second group 15B, and (or) the first group 15A a fin 15 ₃ in the rotational direction last stage, the rear end portion 15b to each other in the rotational direction leading stage of the fin 15 ₄ in the second group 15B, can be made continuous with each other.

According to the said structure, there can exist an effect similar to the 1st form demonstrated previously fundamentally. In particular, since the protrusion height h of each fin 15 is larger at the portion 15c near the tip than at the portion near the base 14, the flow of the liquid flowing into the outer peripheral space S3 of the side lip 12 is By colliding and climbing, the dynamic pressure that presses the outer peripheral portion of the side lip 12 toward the flange portion 22 (see FIG. 2, etc.) of the slinger 20 can be obtained more remarkably. In addition, as the flange portion 22 rotates in the R direction, a part of the liquid, as indicated by the arrow F in FIG. 7A, of each of the fins 15 ₁ to 15 ₃ in the first group 15A. However, as the width of the fins 15 ₁ to 15 ₃ increases, the width of the passage 15d becomes narrower, so that the dynamic pressure generated thereby also affects the flange portion 22. There is an effect of increasing the sliding surface pressure of the side lip 12.

  Next, FIG. 8 is a partial sectional view of a mounted state in which a fourth embodiment in which the present invention is applied as a sealing means of a bearing unit that rotatably supports a wheel on a suspension device is cut along a plane passing through its axis. FIG. In FIG. 8, reference numeral 4 is an outer ring, 5 is a hub to which a center shaft portion 52 is inserted into the outer ring 4 and a wheel (not shown) is attached at the flange portion 51. The hub 5 corresponds to “the other member” described in claim 1.

  On the left side in FIG. 8, a plurality of spheres 6 arranged at predetermined intervals in the circumferential direction are formed on the outer peripheral surface of the central shaft portion 52 of the hub 5 and on the inner peripheral surface of the outer ring 4. The outer ring 4, the central shaft portion 52 of the hub 5, and the spherical body 6 constitute a bearing unit. Between the inner peripheral surface of the outer end portion of the outer ring 4 and the outer peripheral surface of the central shaft portion 52 of the hub 5, an outer ring 31, side lips 32, 33 provided integrally with the outer ring 31, and The sealing device 3 according to the fourth embodiment of the invention with a radial lip 34 is interposed.

  The outer ring 31 is formed by punching a metal plate such as a steel plate and press-molding. The outer ring 31 is a fitting cylinder portion 31a that is press-fitted into the inner peripheral surface 4a of the outer ring 4 with a predetermined tightening allowance, and a bearing internal space The inward flange portion 31b extends from one end on the S4 side to the inner peripheral side. The side lips 32, 33 and the radial lip 34 are made of a rubber-like elastic material and have a common base 35. The base 35 is an inner peripheral portion of the inward flange portion 31 b of the outer ring 31. From the outer ring 31 so as to cover the outer surface thereof. A step portion 31c having a small diameter is formed at the outer end of the fitting tube portion 31a in the outer ring 31, and a gasket portion 36 continuous from the base portion 35 is attached to the outer peripheral surface of the outer ring 4. The inner peripheral surface 4a is in close contact with a predetermined crushing allowance.

  That is, the sealing device 3 positions and sets the outer ring 31 previously coated with a vulcanizing adhesive in a predetermined mold (not shown), and between the outer ring 31 and the inner surface of the mold when the mold is closed. Simultaneously with the vulcanization molding of the side lips 32, 33, the radial lip 34, the base 35, and the gasket portion 36 by filling the formed annular cavity with the unvulcanized rubber material for molding and heating and pressurizing. The base portion 35 is integrally vulcanized and bonded to the outer ring 31.

  The outer side lip 32 corresponds to the “seal lip” described in claim 1, extends from the radial intermediate position in the base portion 35 toward the opposite side to the bearing internal space S 4, and has a tip end. It is formed in a conical shape opened so as to have a relatively large diameter. The side lip 32 is slidable on the end surface 51a of the flange portion 51 of the hub 5 in a state in which the side lip 32 is bent so as to open further to the outer peripheral side from the unmounted state shown by the one-dot chain line in FIG. Have been close to. The end face 51a has a planar shape that is substantially orthogonal to the axis, and corresponds to a "surface that forms a predetermined angle with the axis".

  A large number of fins 37 extending at an incline with respect to the rotation direction of the hub 5 are formed at predetermined intervals in the circumferential direction on the back surface 32 b opposite to the end surface 51 a of the flange portion 51 of the hub 5 in the side lip 32. The back surface 32 b corresponds to a “surface opposite to the other member” described in claim 1. In addition, the fin 37 can be configured in the same manner as the fins 15 shown in FIGS.

  The inner side second side lip 33 extends from the position closer to the inner circumference of the base portion 35 to open to the side opposite to the bearing inner space S4, and has a conical shape opened so that the tip has a relatively large diameter. Is formed. The second side lip 33 is bent from the unmounted state shown by the one-dot chain line in FIG. 8 so as to open further to the outer peripheral side, and the distal end portion 33a has the flange portion 51 of the hub 5 and the central shaft portion 52. Are closely slidable on the curved surface portion 53.

  The radial lip 34 extends from the inner peripheral end portion of the base portion 35 so as to face the bearing inner space S4 side. The inner diameter of the seal edge portion 35a at the inner periphery of the tip end is the center axis of the hub 5 when not mounted. The outer diameter of the portion 52 is smaller than the outer diameter, and in the illustrated mounting state, the outer peripheral surface 52a of the central shaft portion 52 is slidably in contact with an appropriate tightening margin.

  The sealing device 3 according to the fourth embodiment having the above-described configuration is formed in the outer ring 4 in the fitting cylinder part 31a of the outer ring 31 in a state where the gap between the gasket and the inner peripheral surface 4a of the outer ring 4 is sealed. Press fit. The side lips 32 and 33 are slid in close contact with the flange portion 51 and the curved surface portion 53 of the hub 5 to prevent foreign matter such as rainwater, muddy water, or dust from entering the bearing internal space S4 from the outside. At the same time, the radial lip 34 is slid in close contact with the outer peripheral surface 52a of the central shaft portion 52 of the hub 5 to prevent the grease filled in the bearing internal space S4 from leaking to the outside.

  Since the flange portion 51 of the hub 5 gives a centrifugal force to the fluid and the like in contact therewith, the gap between the outer end portion of the outer ring 4 and the flange portion 51 causes a gap between the side lip 32 and the flange portion 51. Dust or the like to be intervened in the sliding portion is shaken off by the centrifugal force and removed to the outer peripheral side. When the back surface 32b side (outer peripheral space S5) of the side lip 32 is in an atmosphere of air, the close force of the side lip 32 to the flange portion 51 of the hub 5 is not attached as shown by a one-dot chain line in FIG. Therefore, the contact surface pressure of the front end portion 32a of the side lip 32 is normally kept small.

  Further, when rainwater or muddy water flows into the back surface 32b side of the side lip 32 from the gap G between the flange portion 51 of the hub 5 and the outer ring 4 due to vehicle traveling in rainy weather or traveling on a flooded road surface, Since the fin 37 acts in the same manner as the fin 15 according to the first to third embodiments described above, the contact surface pressure of the side lip 32 with respect to the flange portion 51 of the hub 5 is increased, and thus excellent against rainwater and muddy water. Has a sealing effect.

  In a normal operation state where no muddy water or the like is present on the back surface 32b side (space S5) of the side lip 32, only when the surface pressure of the side lip 32 against the flange portion 51 of the hub 5 is small and muddy water or the like flows into the space S5. Since the surface pressure increases, wear of the side lip 32 due to sliding with the flange portion 51 is small, and an excellent sealing function is maintained over a long period of time. Further, according to this embodiment, since the slinger 20 as shown in FIG. 2 is not necessary, it is possible to reduce the cost by reducing the number of parts and consequently the number of assembly steps.

  Further, when a small amount of muddy water or the like passes through the sliding portion between the side lip 32 and the flange portion 51 of the hub 5 toward the inner peripheral side, the muddy water or the like travels along the inner peripheral surface 32 c of the side lip 32. Flows into the seal internal space S6 between the second side lip 32 and the second side lip 32 and the curved portion 53 of the hub 5 so as to be sealed. By the swing-off action accompanying the rotation of the side lip 32, it is pushed back to the sliding portion of the side lip 32 and further discharged to the outer peripheral side.

  In each of the above-described embodiments, the present invention is applied to the end face seal type seal lip. For example, a fin as described above is provided on the “surface opposite to the other member” in the radial type seal lip, that is, the outer peripheral surface. Even if it provides, the same effect is realizable.

It is a fragmentary sectional view which cuts and shows the sealing device 3 by the 1st form of this invention by the plane which passes along the axial center. It is a fragmentary sectional view of the mounting state which cut | disconnects and shows the sealing device 3 of FIG. 1 by the plane which passes along the axial center. It is an expanded view which shows the back surface 12b of the side lip 12 in FIG.1 and FIG.2. It is a fragmentary sectional view which shows the cross-sectional shape of the fin 15 cut | disconnected by the III-III line in FIG. It is a fragmentary sectional view which shows the other cross-sectional shape of the fin 15 cut | disconnected by the III-III line in FIG. It is explanatory drawing which shows the 2nd form in this invention, (A) is an expanded view of the back surface 12b of the side lip 12, (B) is BB sectional drawing in (A). It is explanatory drawing which shows the 3rd form in this invention, (A) is an expanded view of the back surface 12b of the side lip 12, (B) is BB sectional drawing in (A). It is a fragmentary sectional view of the mounting state which cut | disconnects and shows the 4th form which applied this invention as a sealing means of the bearing unit which supports a wheel to a suspension apparatus rotatably. It is the fragmentary sectional view of the mounting state which shows the sealing device 120 by a prior art cut | disconnected and shown by the plane which passes along the axial center.

Explanation of symbols

1 Housing (one member)
10 Sealing device body 11, 31 Outer ring 12, 32 Side lip (seal lip)
12b Rear surface (surface opposite to the other member)
13, 34 Radial lip 14 Base 15, 15 ₁ to 15 ₆ , 37 Fin 15 c End portion 15 d passage 20 Slinger (other member)
21 Sleeve part 22 Flange part 22a, 51a End surface (surface which makes a predetermined angle with an axial center)
2 Rotating shaft 3 Sealing device 4 Outer ring (one member)
5 Hub (the other member)
51 Flange 52 Central Shaft 6 Sphere G Gap S1 to S3 Space S4 Bearing Internal Space

Claims (3)

  Of the two members that are arranged substantially concentrically with each other and rotate relative to each other, the tip (12a, 32a) slides on the other member (20, 5). A seal lip (12, 32) that can be brought into close contact with the surface (12b, 32b) opposite to the other member (20, 5) of the seal lip (12, 32) with respect to the rotation direction R. A sealing device, wherein a plurality of fins (15, 37) extending at a predetermined angle α are formed.   The seal lip (12, 32) has an open shape so that its tip has a relatively large diameter, and is in close contact with the surfaces (22a, 51a) that form a predetermined angle with the shaft center. The sealing device according to claim 1.   3. The sealing device according to claim 1, wherein the height (h) and width (w) of the fin (15) are increased at a portion (15c) closer to the tip.

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