JP2015025484A - Sealing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealing device which maintains sealing performance over a long terminal and is manufactured at low costs.SOLUTION: A slinger 8 of a sealing device has a structure where an annular flange part 62 and an annular movable plate 70 are joined in an axial direction through an expansion body 80 which absorbs water and expands its cubic volume. When water intrudes into an axial lip 53, the expansion body 80 expands thereby causing the movable plate 70 to displace to the axial lip 53 side.

Description

  The present invention relates to a sealing device that is assembled to a bearing device used for a flooded application and prevents water from entering the bearing device.

  As shown in FIG. 4 (Patent Document 1), a seal body 110 having a radial lip 111 and an axial lip 112 as shown in FIG. And the sealing device 100 comprised by the slinger 120 is used. In FIG. 4, the left side of the sealing device is the inside of the bearing device, and foreign matters such as water and dust enter from the right side of the sealing device. Intrusion of foreign matter into the bearing device is mainly stopped by the radial lip 111, and the axial lip 112 serves to protect the radial lip 111 from being exposed to a large amount of water.

  However, when used over a long period of time, the axial lip 112 may be worn and water may enter the inside thereof. As shown in FIG. 5 (Patent Document 2), when the axial lip 112 is worn and water enters the inside thereof, the intrusion of the water is detected and the axial lip 112 is moved in the axial direction (right hand direction in FIG. 5). A sealing device 190 that can maintain good sealing performance over a long period of time by moving and increasing the contact pressure with the slinger 120 has been proposed.

  In the sealing device 190, an inflatable portion 114 that absorbs water and expands in volume is formed at the base of the axial lip 112. And the expansion part 114 has the exposed part 116 exposed only in the space 115 formed between the axial lip 112 and the radial lip 111 so that it can absorb and expand only by the water beyond the axial lip 112. A covering portion 117 covered with another rubber material is provided so as not to be exposed outside the axial lip 112.

  When molding a sealing device of this structure, first, in the first step, the rubber material A that absorbs moisture and expands is used to mold the expanding portion 114 on the surface of the cored bar 113, and then in the second step. Using another rubber material B such as nitrile rubber, the axial lip 112 and the radial lip 111 must be molded over the expanded portion 114 manufactured in the first step.

  At this time, the inflatable portion 114 has elasticity and is relatively easily displaced by molding pressure or the like. Therefore, the inflatable portion 114 may be deformed by the molding pressure when the rubber material B is molded in the second step. . For this reason, a large man-hour is required to make the shape accuracy of the axial lip 112 and the thickness of the rubber material B at the exposed portion 116 and the covering portion 117 as designed, and the manufacturing cost is high. It was.

JP 2002-250449 A JP 2011-43200 A

  In view of the above situation, an object of the present invention is to provide a sealing device that can maintain sealing performance over a long period of time and can be manufactured at low cost.

  The sealing device according to claim 1 is mounted in an annular space between an inner member and an outer member that are relatively rotatable and concentrically arranged, and is fitted and fixed to one of the inner member and the outer member. A sealing device configured to prevent the intrusion of water from the outside in the axial direction of the annular space, wherein the slinger is composed of a slinger to be attached and a seal body attached to one of the inner member and the outer member. A cylindrical portion that is fitted and fixed to one of the inner member and the outer member, a flange portion that extends in a radial direction from one axial end of the cylindrical portion, and disposed on the seal body side with respect to the flange portion An annular movable plate formed between the flange portion and the movable plate and joining them together to absorb the water and expand the volume. The seal body has an axial lip that is in sliding contact with the movable plate, and the movable plate is displaced toward the axial lip when the expansion body expands when the seal body is immersed inside the axial lip. It is characterized by doing so.

  According to the first aspect of the present invention, the portion whose volume is expanded by detecting the ingress of moisture is formed on the side of the slinger, which is a separate part from the seal body, so that the rubber used for molding the seal lip Even if the material and the rubber material used for joining the movable plate are different, each part can be manufactured by simply molding it, and the manufacturing process is simplified.

  The sealing device according to claim 2 is the sealing device according to claim 1, wherein the expansion body is exposed to an internal space inside the axial lip and exposed to an external space outside the axial lip. The movable plate has a cylindrical shielding portion that extends coaxially on the outer space side of the expansion body, and the shielding portion is fitted to the flange portion. .

According to the second aspect of the present invention, the expanding portion can be protected from normal water exposure by fitting the shielding portion to the flange portion. Since the shielding part is integrated with the movable plate, the shielding part can be formed simultaneously when the movable plate is manufactured by press molding. Thus, even if no special parts are added, it is possible to prevent the inflating portion from being wetted from the external space, and it is possible to manufacture a sealing device that can maintain good sealing performance for a long time at low cost.
In addition, since the shielding portion has a cylindrical shape, even when the movable plate moves in the axial direction, the fitting gap between the movable plate and the flange portion does not change, and it is not necessary to consider water immersion from this portion. For this reason, since the expansion amount of the expansion part can operate based on the amount of water infiltrated to the inside of the axial lip, an appropriate contact pressure corresponding to the wear amount of the axial lip can be obtained.

  ADVANTAGE OF THE INVENTION According to this invention, while being able to maintain sealing performance over a long period of time, the sealing device which can be manufactured cheaply can be provided.

It is a figure which shows the wheel bearing apparatus incorporating the sealing device concerning embodiment of this invention. It is an enlarged view of the bearing part in FIG. It is a figure which shows the detail of the axial direction cross section of the sealing device concerning embodiment of this invention. It is an application state figure which applied the conventional sealing device to the bearing device for wheels of a car. It is sectional drawing to which the structure which senses water penetration and changes the contact pressure of an axial lip is applied to the conventional sealing device.

  The case where the sealing device according to the embodiment of the present invention is used in a wheel bearing device for supporting a wheel will be described with reference to FIGS. When the wheel bearing device 1 is attached to a vehicle, the left side in FIG. 1 is the outside of the vehicle, so the left side in FIG. 1 is the outer side and the right side in FIG. 1 is the inner side.

  As shown in FIG. 1, the wheel bearing device 1 includes an outer ring member 10 attached to a vehicle body 200, a hub shaft 20 disposed inside the outer ring member 10, and a bearing inner ring 30 fitted to the hub shaft 20. The outer ring member 10, the hub shaft 20, and a plurality of balls 90 disposed between the bearing inner rings 30, and sealing devices 91 and 92 disposed on both sides in the axial direction with the balls 90 interposed therebetween.

  As shown in FIGS. 1 and 2, the outer ring member 10 is provided with a mounting portion 11 having a bolt hole 18 on the outer diameter side, and double row outer raceway surfaces 15 and 16 on the inner diameter side. The cylindrical seal fitting surfaces 12 and 13 are formed coaxially with the outer raceway surfaces on both outer sides in the axial direction of the outer raceway surfaces 15 and 16. The outer ring member 10 is fastened to the vehicle body 200 by inserting a bolt 220 through a bolt hole 18 provided in the mounting portion 11. The outer raceway surfaces 15 and 16 and the seal fitting surfaces 12 and 13 are finished by grinding.

  As shown in FIG. 1, the hub shaft 20 includes a stepped cylindrical shaft portion 17, a cylindrical inlay portion 25 formed at the outer shaft end of the shaft portion 17, and the shaft portion 17 and the inlay portion. 25 and a disc-shaped hub flange 22 extending in the radial direction at a portion sandwiched in the axial direction, and these are formed coaxially.

  The hub flange 22 is provided with a plurality of bolt holes 28 penetrating in the axial direction at a portion close to the outer diameter thereof, and a hub bolt 500 knurled on the lower portion of the neck is provided from the inner side in each bolt hole 28. Has been inserted. The hub bolt 500 has a knurled outer diameter that is fitted with a bolt hole 28 and a squeeze, and the hub bolt 500 and the hub flange 22 are integrally fixed.

  As shown in FIGS. 1 and 2, the shaft portion 17 is formed with an inner raceway surface 24 having an arc-shaped cross section over the entire circumference in the axially central portion of the outer periphery. Since the inner raceway surface 24 is in contact with the ball 90 with a contact angle of about 35 °, a shoulder is formed only on the outer side. That is, the inner raceway surface 24 is continuous with the large-diameter shoulder cylindrical surface 19 on the outer side, and is continuous with the first cylindrical surface 21 having the same outer diameter as the minimum diameter of the inner raceway surface 24 on the inner side. doing.

  An inner ring fitting surface 23 that is a cylindrical surface having an outer diameter smaller than that of the first cylindrical surface 21 is formed on the inner side of the first cylindrical surface 21 of the shaft portion 17 so as to be coaxial with the first cylindrical surface 21. The surface 21 and the inner ring fitting surface 23 are continuous with a stepped end surface 27 formed in a direction orthogonal to the axis.

  An outer side seal slidable contact surface 26 having an arc shape in cross section is formed at a portion sandwiched in the axial direction between the shoulder cylindrical surface 19 of the shaft portion 17 and the hub flange 22. The smallest diameter portion is continuous with the shoulder cylindrical surface 19. The inner raceway surface 24 and the seal sliding contact surface 26 are finished by polishing after being subjected to quenching and hardening treatment.

  The inner periphery of the hub shaft 20 is provided with a cylindrical hole 29 coaxial with the axis, and the spline extends in the axial direction over the entire inner peripheral surface of the shaft portion 17 and a part of the spigot portion 25. Teeth are formed. The constant velocity joint shaft 210 is inserted into the cylindrical hole 29 of the hub shaft 20, and the spline teeth formed on the constant velocity joint shaft 210 mesh with the spline teeth of the hub shaft 20. As a result, the driving force from the engine is transmitted to the hub shaft 20 via the constant velocity joint.

The bearing inner ring 30 has a substantially cylindrical shape, and an inner raceway surface 31 on the inner side having a circular arc shape is formed over the entire circumference of the central portion in the axial direction, and both ends in the axial direction are perpendicular to the axis. Thus, the end faces 36 and 37 are parallel to each other.
Since the inner raceway surface 31 contacts the ball 90 with a contact angle of about 35 ° in the opposite direction to the inner raceway surface 24 formed on the hub shaft 20, the bearing inner ring 30 has a larger inner shoulder diameter. Yes. That is, the inner raceway surface 31 is continuous with the large-diameter shoulder cylindrical surface 32 on the inner side, and the second cylindrical surface 34 having an outer diameter substantially the same as the minimum diameter of the inner raceway surface 31 on the outer side. Is continuous. The bearing inner ring 30 is made of bearing steel. The entire inner race surface 31, the shoulder cylindrical surface 32, end surfaces 36 and 37 on both sides in the axial direction, and the inner diameter surface 38 are polished after being hardened and hardened. Finished by.

  The bearing inner ring 30 is fitted into the inner ring fitting surface 23 with the shoulder cylindrical surface 32 as the inner side, and is press-fitted until the end surface 37 contacts the stepped end surface 27. A plurality of outer raceway surfaces 15 and 16 formed on the outer ring member 10 and inner raceway surfaces 24 and 31 formed on the hub shaft 20 and the bearing inner ring 30 are opposed to each other. A ball 90 is incorporated so that it can roll. The end portion of the hub shaft 20 protruding in the axial direction from the end face 36 of the bearing inner ring 30 is caulked, and the bearing inner ring 30 and the hub shaft 20 are fixed integrally.

  In the brake disc rotor 300 and the wheel 400, a guide hole provided at the center of the shaft is fitted into the inlay part 25, and the bolt hole is inserted into the hub bolt 500 to tighten the nut 501 to the hub flange 22. Fastened and fixed.

  Annulus between the outer seal fitting surface 13 of the outer ring member 10 and the seal sliding contact surface 26 of the hub shaft 20 and between the inner seal fitting surface 12 and the shoulder cylindrical surface 32 of the bearing inner ring 30. Sealing devices 91 and 92 are incorporated in the spaces, respectively, so that water or the like is prevented from entering the raceway surface on which the balls 90 inside the bearing device roll.

  Next, the detailed structure of the sealing device 92 according to the embodiment will be described with reference to FIG. The sealing device 92 includes a seal body 7 attached to the inner seal fitting surface 12 and a slinger 8 attached to the shoulder cylindrical surface 32.

  The seal body 7 includes a cored bar 40 that is fitted to the inner seal fitting surface 12 and an elastic member 50 that is vulcanized and bonded to the cored bar 40 and has a plurality of lips.

  The core metal 40 is composed of a cylindrical portion 41 fitted to the inner seal fitting surface 12, and a flange portion 42 extending radially inward from one axial end of the cylindrical portion 41, The cross section in the axial direction is substantially L-shaped. In the cored bar 40, a cylindrical part 41 and a flange part 42 are integrally manufactured by pressing a thin steel plate such as SPCC.

  The elastic member 50 has a radial lip 51 slidably contacting a cylindrical portion 61 described later of the slinger 8, a sub lip 52 slidably contacting a cylindrical portion 61 described later of the slinger 8, and an axial lip 53 slidably contacting a movable plate 70 described later of the slinger 8. doing.

  The radial lip 51 extends in the axial direction from the inner peripheral end portion of the cored bar 40 toward the inner side, and is formed so that the inner peripheral side of the lip is in sliding contact with the cylindrical portion 61 of the slinger 8. It is the most important lip to prevent the invasion of foreign materials.

  The sub lip 52 is shorter than the radial lip 51 and extends in the axial direction from the inner peripheral end of the cored bar 40 in the direction opposite to the radial lip 51, and the inner peripheral side of the lip is connected to the cylindrical portion 61 of the slinger 8. It is formed so as to be in sliding contact. The degree of contact with the cylindrical portion 61 is almost zero, and the grease in the bearing device mainly serves to prevent leakage of the grease inside the bearing device during rotation of the hub shaft 20. .

  The axial lip 53 extends in a shape in which the diameter increases from the inner peripheral end of the cored bar 40 toward the inner end, and faces the movable plate 70 in the axial direction. The axial lip 53 is a lip having a role of protecting the radial lip 51 from a large amount of foreign matter, water, etc., and wear of the axial lip 53 does not directly cause a decrease in the sealing performance of the seal body 7. .

  These lips 51, 52, 53 are made by molding a rubber material such as NBR (nitrile rubber) with a mold. The mold is composed of a lower mold into which the core metal 40 is inserted and an upper mold for molding the shapes of the lips 51, 52, and 53. For the lip molding, the core metal 40 coated with an adhesive is mounted on the lower mold in advance, and the upper mold is changed to the lower mold with an unvulcanized rubber sheet sandwiched between the upper mold and the lower mold. Press to do.

  At the time of molding, the rubber material is heated to about 200 ° C., and by this heat, the rubber material is vulcanized to form an elastic member 50 having elasticity, and the elastic member 50 and the core metal 40 are added. Sulfur bonded. As the material of the elastic member 50, for example, hydrogenated nitrile rubber, acrylic rubber, silicon rubber, or fluorine rubber is suitably used in addition to nitrile rubber.

  The slinger 8 has a cylindrical cylindrical portion 61 fitted and fixed to the shoulder cylindrical surface 32, a flange portion 62 extending radially outward from one axial end of the cylindrical portion 61, and the flange portion 62. The annular movable plate 70 disposed on the seal body 7 side and the expansion body 80 disposed between the flange portion 62 and the movable plate 70 to join them together and absorb water to expand the volume. ing. The cylindrical portion 61 is manufactured integrally with the flange portion 62 by pressing a thin steel plate such as SPCC, and the axial sectional shape thereof is substantially L-shaped.

  The movable plate 70 includes a flat plate portion 71 and a flange portion 72 extending in the axial direction from one end of the flat plate portion 71 in the axial direction, and the cross section in the axial direction is substantially L-shaped. In the movable plate 70, a flat plate portion 71 and a flange portion 72 are integrally manufactured by pressing a thin steel plate such as SPCC. The flat plate portion 71 needs to have a size such that the axial lip 53 is in sliding contact. The inner diameter dimension of the flat plate portion 71 is set smaller than the diameter of the sliding contact portion of the axial lip 53.

  The inflatable body 80 is molded from water-expandable rubber. The water-expandable rubber is preferably a rubber material obtained by mixing a rubber material or a synthetic resin with a superabsorbent resin. By mixing, moldability, shape retention, mechanical strength and elasticity are obtained.

For example, natural rubber, nitrile rubber, synthetic rubber such as SBR, polyurethane, or the like can be used as the rubber material, and ethylene-vinyl acetate copolymer or the like can be used as the synthetic resin.
The highly water-absorbent resin absorbs and holds about 500 times its own weight of water, and its volume expands greatly with the absorption of water. Examples of the superabsorbent resin include starch-based superabsorbent resin obtained by graft copolymerization of acrylonitrile, acrylic acid, styrene sulfonic acid, vinyl sulfonic acid, etc. with starch, cellulose-acrylonitrile graft copolymer, cellulose-styrene. There are cellulosic superabsorbent resins such as sulfonic acid graft copolymers and crosslinked products of carboxymethylcellulose. In addition, as other highly water-absorbent resins, polyvinyl alcohol-based superabsorbent resins such as cross-linked polyvinyl alcohol, saponified acrylic-vinyl acetate copolymer, cross-linked polyacrylate, polyacrylonitrile-based polymer Acrylic superabsorbent resins such as saponified products and polyethylene glycol diacrylate cross-linked products.
In addition, you may use the said highly water-absorbent resin independently as a material of the expansion body 80. FIG.

  The movable plate 70 is combined so that the surface of the flat plate portion 71 on the side where the flange portion 72 is provided faces the flange portion 62, and the axial end portion 73 of the flange portion 72 is pivoted from the outer surface 65 of the flange portion 62. Combined so as not to protrude in the direction.

  There is a slight gap between the inner peripheral surface 74 of the flange portion 72 and the outer peripheral surface 63 of the flange portion 62, and the movable plate 70 can easily move in the axial direction with respect to the flange portion 62. I can do it. On the other hand, it is desirable that the gap in the radial direction be approximately 0.1 mm or less in order to prevent water intrusion from this portion into the expansion body 80 when the wheel bearing device 1 is submerged.

  The expansion body 80 is an annular flat plate, and has an outer diameter that is equal to the outer diameter of the flange portion 62 and that does not contact the inner peripheral surface of the flange portion 72 of the movable plate 70. The inner diameter dimension is equal to the inner diameter dimension of the flat plate portion 71 of the movable plate 70. Thus, the expansion body 80 is sandwiched between the flange portion 62 and the flat plate portion 71 of the movable plate 70 in the axial direction, and is incorporated so as to be exposed from between the inner peripheral portion of the movable plate 70 and the flange portion 62.

The expansion body 80 is joined to the movable plate 70 and the flange portion 62 by vulcanization adhesion by heat generated when molding with a mold. The mold includes a lower mold that holds the flange portion 62 and an upper mold that holds the movable plate 70. Then, the flange portion 62 and the movable plate 70 to which the adhesive is applied are mounted on the lower die and the upper die in advance, and a disc-shaped rubber sheet made of unvulcanized water-expanded rubber is placed on the lower flange portion 62. Then, when the upper die is pressed against the lower die, the water expansion rubber is sandwiched between the movable plate 70 and the flange portion 62. When the mold is heated to about 200 ° C. in this state, the vulcanization of the water-expanded rubber material proceeds with elasticity due to this heat, and the expansion body 80 is vulcanized and bonded to the flange portion 62 and the movable plate 70. As a result, the slinger 8 is formed.
When the superabsorbent resin is used alone, an adhesive is used for joining the expansion body 80 to the movable plate 70 and the flange portion 62.

Next, a procedure for assembling the sealing device according to the present invention to the wheel bearing device 1 will be described.
When assembling, first, the seal body 7 and the slinger 8 are combined in such an orientation that the axial lip 53 and the movable plate 70 are in contact with each other. At this time, grease is applied to the sliding contact portion of each lip.

A sealing device 92 in which the seal body 7 and the slinger 8 are combined is placed coaxially on the inner side of the wheel bearing device 1 in a direction in which the slinger 8 is on the inner side. The flange portion 62 of the slinger 8 is pressed and pressed simultaneously with a flat jig. By doing so, the cylindrical portion 41 of the seal body 7 is press-fitted to the seal fitting surface 12 of the outer ring member 10, and the cylindrical portion 61 of the slinger 8 is press-fitted to the shoulder cylindrical surface 32 of the bearing inner ring 30. . In addition, the axial dimension of each part is preset so that the axial lip 53 and the movable plate 70 have an appropriate contact pressure when assembled by the above method.
In this way, when the sealing device 92 is mounted in the annular space and is flooded from the outside in the axial direction (right hand direction in FIG. 1), intrusion of muddy water or the like into the bearing (left hand direction in FIG. 1) is prevented. Yes.

Next, the operation of the sealing device 92 according to the present invention will be described.
As shown in FIGS. 1 and 3, in the sealing device 92 incorporated as described above, the slinger 8 rotates as the wheel 400 rotates. When the vehicle travels in the rain and the tires splash the water on the road surface, the wheel bearing device 1 gets wet, and the water enters through the gap between the outer periphery of the slinger 8 (the outer periphery of the flange 72) and the seal body 7. To do. Normally, the axial lip 53 and the movable plate 70 are in sliding contact with a contact pressure, so that they are not immersed inside the axial lip 53.
Moreover, since the outer peripheral side of the expansion body 80 is covered with the flange 72 of the movable plate 70 and a shielding portion is formed so as not to be wetted from the outside, the expansion body 80 does not absorb water, and the movable plate 70 Holds the position.

  In this way, intrusion of water or the like is prevented by the axial lip 53, and the radial lip 51 and the sub lip 52 inside thereof are lubricated by the grease applied at the time of assembly. The sealing function is maintained, and the wheel bearing device 1 smoothly rotates.

  Next, a case will be described in which the wheel bearing device 1 is used for a long period of time, and mud particles contained in the wet water enter the sliding contact portion of the axial lip 53 and the axial lip 53 is worn. When the contact pressure of the axial lip 53 with respect to the movable plate 70 decreases due to this wear, the force that the axial lip 53 prevents water from entering becomes weak, and water may infiltrate beyond the sliding contact portion of the lip. However, when the radial lip 51 is functioning normally, the water inside the bearing is not submerged, and the water submerged beyond the axial lip is surrounded by the axial lip 53, the radial lip 51, and the slinger 8. It stays in one space 54.

  Since the expansion body 80 is exposed in the first space 54, the water staying in the first space 54 is absorbed by the expansion body 80. Since the volume of the expansion body 80 that has absorbed water increases, the movable plate 70 is displaced in the direction away from the flange portion 62 in the axial direction, and the contact pressure between the axial lip 53 and the movable plate 70 increases. When the contact pressure is increased, the sealing performance of the axial lip 53 is improved, so that subsequent entry of water into the first space 54 can be suppressed. As a result, an increase in the amount of moisture in the first space 54 is suppressed, and moisture that has already entered is absorbed by the expansion body 80, so that the amount of moisture staying in the first space 54 is reduced, and the radial lip 51 is attacked. The nature is also reduced.

  Thereafter, when the amount of water that the wheel bearing device 1 is exposed to, such as by changing from rainy weather to fine weather, the moisture absorbed by the expansion body 80 is released at any time, and the size of the expansion body 80 contracts. Returns to its original position.

  If the wear level of the axial lip 53 is further increased by further continuous use, the amount of water immersed in the first space 54 increases. At this time, since the amount of moisture absorbed by the expansion body 80 also increases, the expansion amount of the expansion body 80 is further increased, the movable plate 70 is further displaced toward the axial lip 53, and the axial lip 53 is reduced by wear. The contact pressure can be recovered.

  In addition, since the inner peripheral surface 74 of the flange portion 72 of the movable plate 70 is cylindrical, even if the expansion body 80 expands and the movable plate 70 is displaced in the axial direction, the flange portion 62 and the outer peripheral surface 63 The size of the gap with the inner peripheral surface 74 of the portion 72 does not change. As a result, it is possible to prevent water from entering the gap regardless of the position of the movable plate 70, so that the movable plate 70 can be displaced only in accordance with the amount of water submerged in the first space 54 beyond the axial lip. .

  In addition, when the expansion body 80 absorbs water and its volume expands, it tends to expand between the flange portion 62 and the movable plate 70 with isotropic properties in three directions of the axial direction, the circumferential direction, and the radial direction. . However, since the expansion body 80 is bonded to the flat plate portion 71 and the flange portion 62 of the movable plate 70, the displacement in the circumferential direction and the radial direction when the expansion body 80 absorbs water is limited. For this reason, since the amount of deformation in the axial direction of the expansion body 80 becomes larger than when it is displaced with isotropic property, the axial direction when water is absorbed even if the thickness of the expansion body 80 is reduced. Can be increased, and the contact force of the axial lip 53 can be reliably recovered.

  In addition, by adopting the above structure, the expansion body 80 can have a larger joint surface between the movable plate 70 and the flange portion 62 than the thickness in the axial direction. For this reason, the movable plate 70 can increase its rigidity with respect to the inclination with respect to the flange portion 62 and displacement in directions parallel to each other. As a result, the position of the movable plate 70 is not easily affected by vibration during vehicle travel, and the position is stabilized, so that a better sealing performance can be ensured.

  Thus, even when the axial lip 53 is worn and its sealing performance is lowered, the performance can be recovered. Therefore, the radial lip 51 can maintain the sealing function, and the sealing function as the whole sealing device. Can be secured over a long period of time. As a result, it is possible to provide a wheel bearing device having excellent durability by preventing water and the like from entering the bearing.

  As is clear from the above description, the sealing device according to the present invention can simplify the manufacturing process by configuring the configuration of the portion where the volume is expanded upon detection of moisture ingress on the slinger side. done. As a result, a sealing device for a wheel bearing device that can maintain good sealing performance over a long period of time can be manufactured at low cost.

1: wheel bearing device, 7: seal body, 8: slinger, 10: outer ring member, 12: seal fitting surface, 13: seal fitting surface, 20: hub shaft, 22: hub flange, 25: spigot part, 30: Bearing inner ring, 32: Shoulder cylindrical surface, 40: Metal core, 50: Elastic member, 51: Radial lip, 52: Sub lip, 53: Axial lip, 54: First space, 61: Cylindrical part, 62: Flange Part: 70: movable plate 71: flat plate part 72: collar part 80: expansion body 90: ball 91: sealing device (inner side) 92: sealing device (outer side) 100: sealing device 110 : Seal body 114: Expanding part 120: Slinger

Claims (2)

A slinger that is mounted in an annular space between an inner member and an outer member that are relatively rotatable and concentrically arranged, and is fitted and fixed to one of the inner member and the outer member; the inner member and the In a sealing device that is configured with a seal body that is attached to either one of the outer members, and that prevents water from entering from the outside in the axial direction of the annular space,
The slinger includes a cylindrical portion fitted and fixed to one of the inner member and the outer member, a flange portion extending in a radial direction from one axial end of the cylindrical portion, and the seal against the flange portion. It is composed of an annular movable plate disposed on the main body side, an expansion body that is disposed between the flange portion and the movable plate and joins them, and absorbs water to expand the volume.
The seal body has an axial lip that is in sliding contact with the movable plate, and when the expansion body expands when immersed in the axial lip, the movable plate is displaced toward the axial lip. A sealing device characterized by that.   The expandable body is exposed to the internal space inside the axial lip, and the movable plate extends coaxially to the external space side of the expandable body so as not to be exposed to the external space outside the axial lip. The sealing device according to claim 1, further comprising: a cylindrical shielding portion that fits the flange portion.

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