Sealing structure

Abstract

To provide a sealing structure capable of achieving both sealing performance and drainage performance.SOLUTION: A sealing structure of a bearing device 1 includes a sealing device 10 which is mounted between two members of an outer member 2 as a fixed member and an inner member 5 relatively coaxially rotating with respect to the outer member and seals a sealed space S. The sealing device includes a slinger member 11 fitted to the inside member and a seal member 14 fitted to the outside member, and an 12c of a second cylindrical part of a slinger core body part 12 is arranged so that a labyrinth part R is constituted between the second cylindrical part and the outside member opposed to the second cylindrical part in the radial direction. A discharge hole 20 penetrating in the radial direction is provided on the sealed space side from an installation position of the slinger disk part and at a lower part of the outer member, and a slinger lip part 13b and a seal lip part 16b are provided alternately and in a non-contact state.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a sealing structure for a bearing device that includes a sealing device that seals between two members, an outer member and an inner member. [Background technology]

[0002] 2. Description of the Related Art Conventionally, bearing devices in vehicles such as automobiles are exposed to the outside space and installed in positions close to the ground, and are therefore in an environment where they are susceptible to attack by muddy water and the like. Therefore, Patent Documents 1 and 2 listed below disclose a bearing device provided with a drain hole or drain portion for draining water or the like that has infiltrated into the outer member of the bearing device. Patent Documents 1 and 2 also disclose a sealing device that seals between two members, an outer member and an inner member. These sealing devices include two members that are fitted into the outer member and the inner member, respectively, and seal the sealed space. In such sealing devices, increasing the number of seal lips or labyrinth seals to improve sealing performance can reduce the amount of water or the like that infiltrates, but this also reduces the amount of water or the like that is drained that has infiltrated into the sealing device, so achieving both good sealing performance and good drainage performance becomes a challenge. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-237791 [Patent Document 2] Japanese Patent Publication No. 2022-147755 Summary of the Invention [Problem to be solved by the invention]

[0004] The device described in Patent Document 1 has a drain hole formed in the outer member of the bearing device, but as shown in FIG. 2 of Patent Document 1, the drain hole is formed downward on the outer member outside the sealing device, and is not a drain hole for discharging water or the like that has entered the sealing device.

[0005] Furthermore, in the device described in Patent Document 2, a drain portion is formed by cutting out a portion of the axial end of the outer member, so although the ability to discharge water and the like that has infiltrated into the sealing device can be improved, there is a possibility that water and the like may infiltrate into the sealing device from the external space through the drain portion. Furthermore, in the case of Patent Document 2, it is necessary to form a drain portion by cutting out a portion in the circumferential direction not only in the outer member but also in the inner fitting portion of the core metal of the sealing device, and it is also necessary to align the drain portion with the drain portion of the core metal when attaching it to the outer member.

[0006] The present invention has been proposed in consideration of the above circumstances, and its object is to provide a sealing structure that can achieve both sealing performance and drainage performance. [Means for solving the problem]

[0007] In order to achieve the above object, the sealing structure of the present invention is a sealing structure for a bearing device, which is equipped with a sealing device that is mounted between two members, an outer member that is a fixed member, and an inner member that rotates coaxially relative to the outer member, and seals a sealed space, the sealing device comprising a slinger member that is fitted to the inner member, and a seal member that is fitted to the outer member, and is mounted in combination at an axial end between the two members, the slinger member comprising a first cylindrical portion that is fitted to the outer peripheral surface of the inner member, a slinger core portion having a slinger disc portion that extends radially outward from one axial end of the first cylindrical portion, and a second cylindrical portion that extends radially outward from the outer radial end of the disc portion, and a slinger seal portion that is fixed to the slinger core portion, The slinger member comprises a core cylindrical portion that is fitted to the inner surface of the outer member, a core portion having a core disk portion extending radially inward from either axial end of the core cylindrical portion, and a seal portion fixed to the core portion, and the second cylindrical portion is arranged so that a labyrinth portion is formed between the second cylindrical portion and the outer member that faces it radially, and a radially penetrating discharge hole is provided on the sealed space side of the installation position of the slinger disk portion and in a lower portion of the outer member, and a slinger lip portion formed in the slinger seal portion and extending at an angle toward the outer member, and a seal lip portion formed in the seal portion and extending at an angle toward the entrance side of the labyrinth portion are arranged alternately and in a non-contacting state.

[0008] In the above sealing structure, the discharge hole has an introduction side opening communicating with the labyrinth portion, The opening dimension of the inlet-side opening may be seven times or more the radial gap dimension of the labyrinth portion. In the above-described sealing structure, the opening dimension of the discharge hole at the discharge-side opening communicating with the external space may be smaller than the opening dimension of the inlet-side opening.

[0009] In the sealing structure, the second cylindrical portion may be arranged so as not to overlap the discharge hole. In the sealing structure, the seal lip portion may be arranged so as to overlap an introduction side opening of the discharge hole that communicates with the labyrinth portion. [Effects of the Invention]

[0010] The sealing structure of the present invention has the above-described configuration, and therefore can achieve both sealing performance and drainage performance. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic cross-sectional view showing an example of a bearing device to which a sealing structure according to a first embodiment of the present invention is applied; [Figure 2] 1A is an enlarged view of the X1 portion of FIG. 1, and FIG. 1B is an enlarged view of the X2 portion of FIG. 1, both of which are schematic cross-sectional views showing a sealing device used in the sealing structure according to the embodiment. [Figure 3] (a) and (b) are diagrams for explaining the flow of muddy water and other substances from the time they enter until they are discharged, and (a) corresponds to (a) in Figure 2, and (b) corresponds to (b) in Figure 2. [Figure 4] 1A is a schematic plan view showing a discharge hole according to the embodiment, FIG. 1B is a modified example thereof, and FIG. 1C is a diagram for explaining a modified example of the discharge hole according to the embodiment, showing a schematic plan view showing a portion where the discharge hole is formed. [Figure 5] 1, and (b) is an enlarged view of the X1 portion of FIG. 1, and is a schematic cross-sectional view showing a sealing device used in a sealing structure according to a second embodiment. [Figure 6] 10(a) to 10(c) are diagrams for explaining evaluation tests conducted by changing the number and size of discharge holes formed in the outer member of the bearing device, and are schematic side views showing the positions at which the discharge holes are formed. [Figure 7] The results of the evaluation test are shown in the graph. DETAILED DESCRIPTION OF THE INVENTION

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that in some drawings, some of the detailed reference numerals used in other drawings are omitted. The sealing structure according to this embodiment is a sealing structure for a bearing assembly 1, which includes a sealing device 10 that is mounted between two members, an outer member 2, which is a fixed member, and an inner member 5 that rotates coaxially relative to the outer member 2, and seals a sealed space S. The sealing device 10 includes a slinger member 11 that is fitted to the inner member 5 and a seal member 14 that is fitted to the outer member 2, and is mounted in combination at an axial end 1a between the two members. The slinger member 11 includes a first cylindrical portion 12a that is fitted to the outer peripheral surface 4b of the inner member 5, a slinger core portion 12 that has a slinger disc portion 12b that extends radially outward from an axial end 12aa on one side of the first cylindrical portion 12a, and a second cylindrical portion 12c that extends radially outward from an axial end 12ba on the outer diameter side of the slinger disc portion 12b, and a slinger seal portion 13 that is fixed to the slinger core portion 12.

[0013] The seal member 14 includes a core cylindrical portion 15a fitted to the inner circumferential surface 2b of the outer member 2, a core portion 15 having a core disk portion 15b extending radially inward from one axial end 15ba of the core cylindrical portion 15a, and a seal portion 16 fixed to the core portion 15. The second cylindrical portion 12c is arranged so that a labyrinth portion R is formed between the second cylindrical portion 12c and the outer member 2 facing it in the radial direction, and a discharge hole 20 penetrating radially is provided in a lower portion of the outer member 2, closer to the sealed space S than the installation position of the slinger disk portion 12b. A slinger lip portion 13b formed in the slinger seal portion 13 and extending obliquely toward the outer member 2, and a seal lip portion 16b formed in the seal member 14 and extending obliquely toward the inlet Ra of the labyrinth portion R, are arranged alternately and non-contactingly. Details will be described below.

[0014] First, the sealing structure according to the first embodiment will be described with reference to Figures 1 to 3. Figures 3(a) and 3(b) are the same cross-sectional views as Figures 2(a) and 2(b), but the muddy water is shown schematically as a circle in order to explain the process from when muddy water enters the sealing device 10 until it is discharged. The muddy water is marked with a "w", but some of the markings have been omitted.

[0015] FIG. 1 shows a schematic diagram of an example of a bearing device 1 to which a sealing structure is applied. As shown in FIG. 1, the bearing device 1 supports a wheel (not shown) of a vehicle such as an automobile so as to be rotatable about its axis. The bearing device 1 generally includes an outer ring 2 corresponding to the outer member described above, an inner ring 5 corresponding to the inner member described above, and two rows of rolling elements (balls) 6 interposed between the outer ring 2 and the inner ring 5. The inner ring 5 is made up of a hub ring 3 and an inner ring member 4, and the inner ring member 4 is fitted integrally with the vehicle body side of the hub ring 3. A drive shaft 7 is coaxially spline-fitted to the hub ring 3, and the drive shaft 7 is connected to a drive source (drive transmission unit) (not shown) via a constant velocity joint 8. The drive shaft 7 is integrated with the hub ring 3 by a nut 9, which prevents the hub ring 3 from falling off the drive shaft 7. The inner ring 5 (hub ring 3 and inner ring member 4) is rotatable around the axis L relative to the outer ring 2, and the outer ring 2 and inner ring 5 form two relatively rotatable members, forming an annular sealed space S. Within the sealed space S, two rows of rolling elements 6 are held by a retainer 6a, and the raceways 2a of the outer ring 2 and the raceways 3a, 4a of the hub ring 3 and inner ring member 4 are rollably interposed. The hub ring 3 has a cylindrical hub ring body 3b and a hub flange 3d that extends radially outward from the hub ring body 3b via a rising base portion 3c, and a wheel is attached and fixed to the hub flange 3d with bolts 3e and nuts (not shown).

[0016] The sealing device 10 is mounted between two members, i.e., between the outer ring 2 and the inner ring member 4, and seals the end 1a of the sealed space S on the vehicle body side (one axial side). In addition, a sealing device 40 is mounted between the outer ring 2 and the hub wheel 3, and seals the end 1b of the sealed space S on the wheel side (the other axial side). These seal both axial ends of the sealed space S, preventing foreign matter such as muddy water from entering the sealed space S and preventing lubricant (grease, etc.) filled in the sealed space S from leaking to the outside.

[0017] 2(a) is an enlarged view of portion X1 in FIG. 1, and FIG. 2(b) is an enlarged view of portion X2 in FIG. 1. While FIGS. 2(a) and 2(b) each show separate cross sections, the sealing device 10 is a single annular body that is attached to the end 1a on the vehicle body side (one axial side) of the sealed space S of the bearing device 1. FIG. 2(a) shows a cross-sectional view of the sealing device 10 attached between the outer ring 2 and the upper portion of the inner ring member 4, and FIG. 2(b) shows a cross-sectional view of the sealing device 10 attached between the outer ring 2 and the lower portion of the inner ring member 4. The sealing device 10 includes a slinger member 11 that is fitted to the outer peripheral surface 4b of the inner ring member 4, and a seal member 14 that is fitted to the inner peripheral surface 2b of the outer member 2. A discharge hole 20 is formed in the lower part (ground side) of the outer ring 2, on the sealed space S side of the slinger disc portion 12b of the slinger member 11, which penetrates radially and communicates with the external space 30 (see Figure 2(b)).

[0018] The slinger member 11 is an annular member and includes a slinger core portion 12 and a slinger seal portion 13. The slinger core portion 12 is formed by pressing a steel plate such as SPCC or SUS so that one cross section is approximately U-shaped. The slinger core portion 12 has a first cylindrical portion 12a that fits onto the outer peripheral surface 4b of the inner ring member 4, a slinger disk portion 12b that extends radially outward from an end portion 12aa on one axial side of the first cylindrical portion 12a, and a second cylindrical portion 12c that extends radially outward from an end portion 12ba on the outer radial side of the slinger disk portion 12b. The second cylindrical portion 12c is disposed adjacent to the inner peripheral surface 2b of the outer ring 2 so as to form a labyrinth portion R (gap). In the illustrated example, the second cylindrical portion 12c is formed so that the opposing surfaces of the second cylindrical portion 12c and the inner peripheral surface 2b are approximately parallel. Since the sealing device 10 does not have a sliding seal lip to meet the requirements for high durability and low torque, the gap dimension A of the entrance Ra of the labyrinth portion R, which serves as an entrance for muddy water and the like to enter from the external space, is set to 0.1 mm to 2 mm, and is preferably as small as possible. In addition, the second cylindrical portion 12c is arranged so as not to overlap with the introduction side opening 21 of the discharge hole 20 which communicates with the labyrinth portion R.

[0019] The slinger seal portion 13 is formed from an elastic material such as NBR, H-NBR, ACM, AEM, or FKM. The slinger seal base 13a is arranged to cover the entire surface of the slinger core portion 12 facing the sealed space S, and includes a slinger lip portion 13b extending from the other axial end portion 12ab of the first cylindrical portion 12a. The slinger lip portion 13b extends obliquely from the other axial end portion 12ab of the first cylindrical portion 12a toward the outer ring 2 and the sealed space S. Its length is such that it does not come into contact with the seal lip portion 16b of the seal member 14. The sealing device 10 is configured to enhance the sealing performance of the inner ring 5 region. Although not shown, a magnetized portion in which north and south poles are magnetized alternately and continuously in the circumferential direction may be fixed to the slinger disc portion 12b. The magnetized portion is disposed so as to face a magnetic sensor provided on the vehicle body or the like in the axial direction, thereby forming a magnetic encoder that detects the rotation speed of the wheel, etc.

[0020] The seal member 14 is an annular member comprising a core portion 15 and a seal portion 16. The core portion 15 is formed by pressing a steel plate such as SPCC or SUS so that one cross section is roughly L-shaped. The core portion 15 has a core cylindrical portion 15a that is fitted to the inner circumferential surface 2b of the outer ring 2 via a seal cylindrical portion 16d, and a core disk portion 15b that extends radially inward from one axial end 15ba of the core cylindrical portion 15a. The seal portion 16 is formed from an elastic material such as NBR, H-NBR, ACM, AEM, or FKM, and is fixed to the core portion 15. The seal portion 16 has a seal cylindrical portion 16d fixed to the core cylindrical portion 15a, a seal base portion 16a fixed to the core disc portion 15b, a seal lip portion 16b formed extending at an angle from the inner diameter side of the core disc portion 15b toward the outer diameter side end portion 12ba of the slinger disc portion 12b of the slinger member 11, and a grease lip 16c formed extending from the inner diameter side end portion 15bb of the core disc portion 15b so as to be in sliding contact with the outer peripheral surface 4b of the inner ring member 4. In this way, the slinger lip portion 13b formed in the slinger seal portion 13 and extending at an angle toward the outer member 2, and the seal lip portion 16b extending at an angle toward the inlet Ra of the labyrinth portion R are arranged alternately and in a non-contact state. The core cylindrical portion 15 a is fitted to the inner peripheral surface 2 b at a position that does not overlap with the discharge hole 20 formed in the lower portion of the outer ring 2 and is attached to a position near the discharge hole 20 .

[0021] The seal lip portion 16b is an axial lip formed so that its tip end 16ba is close to but does not slide against the slinger disc portion 12b. The seal lip portion 16b is disposed in a position that radially overlaps the second cylindrical portion 12c, and the space surrounded by the second cylindrical portion 12c and the seal lip portion 16b forms a first seal space S1 (see FIG. 3(a)) into which muddy water or the like that has infiltrated through the labyrinth portion R first enters. Muddy water or the like that has passed between the tip end 16ba of the seal lip portion 16b and the slinger seal base 13a fixed to the slinger disc portion 12b reaches a second seal space S2 (see FIG. 3(a)) surrounded by the slinger lip portion 13b, the first cylindrical portion 12a, and the slinger disc portion 12b. The tip end 13ba of the slinger lip 13b is formed to rise toward the outer ring 2, so that the slinger lip 13b has the effect of blocking and storing muddy water, etc. Muddy water, etc. that passes through the slinger lip 13b reaches the third seal space S3 (see FIG. 3(a)) surrounded by the grease lip 16c, the seal lip 16b, and the slinger lip 13b.

[0022] According to the sealing device 10 of this embodiment, the portion that serves as an inlet for muddy water and the like is configured as the labyrinth portion R, and the slinger lip portions 13b and seal lip portions 16b provided in the sealing device 10 are arranged alternately and in a non-contact state, so that it is possible to improve sealing performance and durability while suppressing an increase in rotational torque without forming a complex labyrinth structure. Furthermore, according to the sealing device 10 of this embodiment, even if muddy water and the like infiltrates the second seal space S2 and further the third seal space S3, the muddy water and the like flows by gravity toward the lower portion (ground side) of the outer ring 2, which is the fixed member, as shown by the outline arrow in Figure 3(b), and when it reaches the first seal space S1, the muddy water and the like can be naturally discharged from the discharge hole 20.

[0023] The sealing device attached to the bearing assembly 1 can reduce torque by providing a non-contact lip, and increasing the complexity of the labyrinth structure improves sealing performance, but it is difficult to drain muddy water and other contaminants that have entered the second sealing space S2 or the third sealing space S3 within the sealing device 10. According to the sealing structure of this embodiment, a drain hole 20 is formed on the sealed space S side of the installation position of the slinger disc portion 12b and below the outer ring 2. Therefore, when the slinger member 11 of the sealing device 10 reaches a lower portion of the bearing assembly 1 as it rotates, muddy water and other contaminants that have entered the sealing device 10 can be drained through the drain hole 20. This prevents muddy water and other contaminants from accumulating within the sealing device 10, improving the durability of the sealing device 10. Furthermore, the slinger lip portion 13b and the grease lip 16c are alternately inclined downward toward the drain hole 20, allowing muddy water and other contaminants to be smoothly guided to the drain hole 20. Furthermore, second cylindrical portion 12c of slinger member 11 is positioned close to discharge hole 20 and does not overlap with introduction-side opening 21, which communicates with labyrinth portion R of discharge hole 20, thereby further improving drainage. For example, if second cylindrical portion 12c is positioned so as to overlap introduction-side opening 21, labyrinth portion R cannot be formed at this overlapping portion. On the other hand, if the position at which second cylindrical portion 12c is positioned and the position at which introduction-side opening 21 are formed are separated from each other, this will affect the installation position of seal member 14, making it difficult to alternately arrange seal lip portion 16b and slinger lip portion 13b.

[0024] Next, the discharge hole 20 will be described with reference to FIGS. 2(b) and 4. The configuration of the discharge hole 20 is not particularly limited. For example, the shape of the discharge hole 20 may be circular in plan view as shown in FIG. 4(a) or elliptical in plan view as shown in FIG. 4(b). Although not shown, the discharge hole 20 may also be substantially rectangular, triangular, or polygonal in plan view. The discharge hole 20 may be a through hole having an inlet-side opening 21 communicating with the labyrinth portion R and a discharge-side opening 22 communicating with the external space 30. The opening dimension B1 of the inlet-side opening 21 and the opening dimension B2 of the discharge-side opening 22 may be the same as shown in FIG. 2(b). Alternatively, the opening dimension B2 of the discharge-side opening 22 communicating with the external space 30 may be smaller than the opening dimension of the inlet-side opening 21 as shown in FIG. 4(c). If the diameter of the discharge side opening 22 is made small, it becomes difficult for muddy water or the like to enter from the external space 30 side through the discharge hole 20. In addition, according to the inventor's test, it was found that the cross-sectional area of ​​the discharge hole 20 is 25 mm 2 It was found that drainage performance can be improved by making the opening dimension B1 of the inlet-side opening 21 at least seven times the radial gap dimension A of the labyrinth portion R. Furthermore, it was found that drainage performance can be improved by making the opening dimension B1 of the inlet-side opening 21 at least seven times the radial gap dimension A of the labyrinth portion R. Furthermore, the number of discharge holes 20 formed is not limited to one location as shown in FIG. 2(b). For example, as shown in FIG. 6(b), multiple discharge holes may be formed along the circumferential direction of the inner peripheral surface 2b of the outer ring 2. Furthermore, when the discharge holes 20 are circular as shown in FIG. 4(a), their diameter is not particularly limited, and can be, for example, 3 mm to 7 mm. Evaluation tests in which the diameter and number of holes formed were changed will be described later with reference to FIGS. 6 and 7.

[0025] Next, a sealing structure according to a second embodiment will be described with reference to Fig. 5. Description of configurations and effects common to the above embodiment will be omitted. The sealing device 10A shown in Fig. 5(a) and Fig. 5(b) is similar to the above embodiment in that a discharge hole 20 that penetrates radially and communicates with the external space 30 is formed in a lower portion of the outer ring 2, and the configuration of the seal member 14 is the same as that of the above embodiment, but the configuration of the slinger member 11 is different.

[0026] The slinger member 11 of the sealing device 10A is an annular member and includes a slinger core portion 12 and a slinger seal portion 13. The slinger core portion 12 is formed by pressing a steel plate such as SPCC or SUS. The slinger core portion 12 has a first cylindrical portion 12a that fits onto the outer peripheral surface 4b of the inner ring member 4, a slinger disk portion 12b that extends radially outward from an end portion 12ac on the other axial side of the first cylindrical portion 12a, and a second cylindrical portion 12c that extends radially outward from an end portion 12ba on the outer radial side of the slinger disk portion 12b. The second cylindrical portion 12c is disposed adjacent to the outer peripheral surface 2c of the outer ring 2 so as to form a labyrinth portion R (gap). In the illustrated example, the second cylindrical portion 12c is formed so that the opposing surfaces of the second cylindrical portion 12c and the outer peripheral surface 2c are approximately parallel.

[0027] The slinger seal portion 13 is made of an elastic material such as NBR, H-NBR, ACM, AEM, or FKM, and includes a slinger seal base 13a arranged to cover the entire surface of the slinger core portion 12 facing the sealed space S, a seal protrusion 13aa formed to protrude from the other axial end 12ac of the first cylindrical portion 12a, a slinger lip portion 13b extending from the seal protrusion 13aa so as to be configured differently from the seal lip portion 16b, and a slinger second lip portion 13c extending from the slinger seal base 13a toward the core cylindrical portion 15a. The slinger lip portion 13b extends obliquely from the seal protrusion 13aa toward the outer ring 2 (the sealed space S), and its length is set to be long enough so as not to come into contact with the seal lip portion 16b provided on the seal member 14. The slinger second lip portion 13c has a protruding base 13ca located radially outward from the protruding base 16bb of the seal lip portion 16b, and is formed to extend obliquely so as to be alternately configured with the seal lip portion 16b.

[0028] The gap dimension A of the entrance Ra of the labyrinth portion R and the opening dimensions B1, B2 of the inlet-side opening 21 and the discharge-side opening 22 of the discharge hole 20 are the same as those in the above embodiment. Furthermore, the end 12ca (including the slinger seal base 13a) of the second cylindrical portion 12c is positioned so as not to overlap with the discharge-side opening 22. This allows muddy water and the like to be easily drained when being discharged from the discharge hole 20. Although not shown, the end 12ca of the second cylindrical portion 12c may also be positioned so as to overlap with the discharge-side opening 22. In this case, it is possible to prevent muddy water and the like from entering from the discharge-side opening 22 side. Furthermore, since the distance of the labyrinth portion R can be secured long, the sealing performance of the labyrinth can be improved.

[0029] According to the sealing device 10A of this embodiment, the entry point for muddy water and the like is formed on the outer peripheral surface 2c of the outer ring 2, and a labyrinth portion R is formed between the outer peripheral surface 2c of the outer ring 2 and the second cylindrical portion 12c. A second labyrinth portion R' is also formed between the opposing surfaces of the end face 2d of the outer ring 2 and the slinger disc portion 12b. This ensures a long distance from the entry point to the fourth seal space S4 enclosed by the outermost slinger second lip portion 13c and the inner peripheral surface 2b of the outer ring 2, thereby improving sealing performance. Furthermore, the slinger second lip portion 13c and the seal lip portion 16b, and the seal lip portion 16b and the slinger lip portion 13b provided in the sealing device 10A are arranged alternately and without contact, thereby improving sealing performance and durability while suppressing an increase in rotational torque. Furthermore, according to the sealing device 10A of this embodiment, even if muddy water or the like enters the first sealing space S1 to the fourth sealing space S4, the muddy water or the like will flow due to gravity toward the lower part (ground side) of the outer ring 2, which is the fixed member, and once it reaches the fourth sealing space S4, the muddy water or the like can be naturally discharged from the discharge hole 20.

[0030] Next, with reference to FIGS. 6 and 7, a water injection test conducted by the inventors will be described. In this test, water was injected into a test bearing assembly, and the amount of leakage from the entrance Ra of the labyrinth portion R of the sealing device 10A was measured under the following conditions, with the presence or absence, diameter, and number of drain holes 20 varied. The shape and configuration of the sealing device used in the test were the same as those of the sealing device 10A shown in FIGS. 5(a) and 5(b), and therefore a description thereof will be omitted. In the table of FIG. 7, since no leakage occurred at rotation speeds of 500 to 1500 rpm, even without drain holes 20, the upper limit was set at 600 rpm. Note that since the water injection test forcibly injects water toward the sealing device 10A, while preventing water from entering the sealing device 10A, if the drainage performance is poor, water will accumulate inside the sealing device 10A. The amount of water that cannot be drained and leaks out can be used to evaluate the sealing performance and drainage performance. Therefore, the smaller the leakage amount, the better the sealing performance and drainage performance can be evaluated.

[0031] <Test conditions> Rotation speed: 0 rpm, 100 rpm, 200 rpm, 300 rpm, 400 rpm, 500 rpm, 1000 rpm, 1500 rpm Water spray duration: 1 minute each Injection amount: 150ml / sec Rotation direction: Clockwise Rotation Discharge hole diameter: Test No. 1: None, Test No. 2 to Test No. 4: Approximately 3 mm, Test No. 5: Approximately 6 mm Labyrinth R clearance dimension A: 0.85 mm

[0032] <Test Results> <Test No. 1> In Test No. 1, a water injection test was conducted without providing the test bearing device with a drain hole 20. In this case, no leakage occurred between 500 and 1000 rpm, and the amount of leakage increased as the rotation speed decreased from 0 to 400 rpm.

[0033] <Test No. 2> In Test No. 2, as shown in Figure 6(a), a drain hole 20 with a diameter of approximately 3 mm was provided in one location on the lower part of the outer ring 2, and a water injection test was performed. As shown in Figure 7, leakage occurred between 0 and 200 rpm, but the amount was about 200 ml, which was less than in Test No. 1, and the results prove the effectiveness of the drain hole 20.

[0034] <Test No. 3> In Test No. 3, drain holes 20 with a diameter of approximately 3 mm were provided in two locations on the lower part of the outer ring 2, and a water injection test was performed. As shown in Figure 7, only a small amount of leakage of less than 50 ml was confirmed between 0 and 400 rpm, and no leakage was confirmed above 500 rpm. This result proves that even with a hole diameter of approximately 3 mm, providing two drain holes 20 has a significant effect on sealing and drainage.

[0035] <Test No. 4> In Test No. 4, as shown in Figure 6(b), drain holes 20 with a diameter of approximately 3 mm were provided in three locations on the lower part of the outer ring 2, and a water injection test was conducted. As shown in Figure 7, the leakage amount was less than in Test No. 1 and Test No. 2. Therefore, it can be said that the more drain holes 20 there are, the better, and although the leakage amount was greater than in Test No. 3, it was still less than 170 ml, which can be said to prove the effectiveness of the sealing and drainage properties.

[0036] <Test No. 5> In Test No. 5, a drain hole 20 with a diameter of approximately 6 mm was provided in one location on the lower part of the outer ring 2, as shown in Figure 6(c), and a water injection test was conducted. As shown in Figure 7, in Test No. 5, no leakage was confirmed. Therefore, the results prove that even if there is only one drain hole 20, if the hole diameter is approximately 6 mm, in other words, if the gap dimension A of the labyrinth portion R is 0.85 mm x 7 times or more, it has an extremely effective effect in terms of sealing and drainage.

[0037] <Summary of test results> The above tests showed that when the rotation speed was set to 0 to 500 rpm, leakage occurred without the discharge holes 20, but that the presence of the discharge holes 20 reduced leakage. It was also found that even when the discharge holes 20 were present, two holes were better than one. However, since the amount of leakage was less with two holes than with three, it is assumed that increasing the number of holes affects the direction of rotation. Increasing the diameter of the discharge holes 20 from 3 mm to 6 mm reduced the amount of leakage. This means that a sufficient amount of drainage was ensured relative to the amount of inflow. However, when put into practical use, the diameter of the discharge-side opening 22 must be set taking into account the inflow from the ground side (external space 30) into the discharge holes 20.

[0038] The configurations of the bearing device 1 and sealing devices 10, 10A described above are not limited to those described above or illustrated. For example, the bearing device 1 is not limited to a single-row configuration but may be a double-row configuration, and the shapes and configurations of the outer ring 2 and inner ring 5 are not limited to those illustrated. The shapes and number of lips of the core portion 15 and seal portion 16 constituting the seal member 14 of the sealing device 10, 10A are also not limited to those illustrated. For example, an oil seal may be provided axially in addition to the grease lip 16c. Furthermore, the shapes and number of lips of the slinger core portion 12 and slinger seal portion 13 constituting the slinger member 11 are not limited to those illustrated, as long as the alternately arranged seal lip portions 16b and slinger lip portions 13b do not interfere with each other as in the above embodiment. For example, the slinger core portion 12 may have a generally S-shaped cross section, and the slinger seal base portion 13a is not limited to covering the entire surface of the slinger core portion 12 facing the sealed space S, but may cover only a portion, such as only half of the radial surface. Furthermore, the sealing device 10, 10A may be either metal-fitted to the outer ring 2 and inner ring member 4 (see the first cylindrical portion 12a in Figure 2(a)) or fitted via an elastic material (see the core cylindrical portion 15a in Figure 2(a)). [Explanation of symbols]

[0039] 1 Bearing device 2 Outer ring (outer member) 2b Inner surface 4 Inner ring (inner member) 4b Outer surface 6 rolling elements 10,10A sealing device 11 Slinger member 12 Slinger core body 12a First cylindrical part 12b Slinger disc 12c Second cylindrical section 13 Slinger seal part 13a Slinger seal base 13b Sling lip part 13c Slinger second lip 14 Sealing material 15 Core body part 15a Core cylindrical part 15b Core disc part 16 Seal part 16a Seal base 16b Seal lip 16c grease lip S Sealed space 20 Discharge hole 30 Exterior Space

Claims

1. A sealing structure for a bearing device including a sealing device that is mounted between two members, an outer member that is a fixed member and an inner member that rotates coaxially relative to the outer member, and seals a sealed space, The sealing device includes a slinger member fitted to the inner member and a seal member fitted to the outer member, and is mounted in combination at an axial end between the two members, The slinger member comprises a first cylindrical portion fitted to the outer peripheral surface of the inner member, a slinger core portion having a slinger disc portion extending radially outward from one axial end of the first cylindrical portion, and a second cylindrical portion extending radially outward from the outer axial end of the disc portion, and a slinger seal portion fixed to the slinger core portion; the seal member comprises a core cylindrical portion fitted to the inner peripheral surface of the outer member, a core portion having a core disk portion extending from either one axial end of the core cylindrical portion toward the inner diameter side, and a seal portion fixed to the core portion; the second cylindrical portion is disposed so as to define a labyrinth portion between the second cylindrical portion and the outer member facing the second cylindrical portion in the radial direction, a discharge hole penetrating radially through the outer member at a position closer to the sealed space than the installation position of the slinger disc portion; A sealing structure characterized in that a slinger lip portion formed in the slinger seal portion and extending at an angle toward the outer member, and a seal lip portion formed in the seal portion and extending at an angle toward the inlet side of the labyrinth portion are arranged alternately and in a non-contact state.

2. In claim 1, the discharge hole has an introduction side opening communicating with the labyrinth portion, A sealing structure characterized in that the opening dimension of the introduction side opening is at least seven times the radial gap dimension of the labyrinth portion.

3. In claim 2, A sealed structure, wherein the discharge hole has an opening dimension of a discharge side opening communicating with an external space that is smaller than the opening dimension of the introduction side opening.

4. In claim 1, A sealing structure characterized in that the second cylindrical portion is arranged so as not to overlap the discharge hole.

5. In claim 1, A sealing structure characterized in that the seal lip portion is arranged so as to overlap an introduction side opening portion that communicates with the labyrinth portion of the discharge hole.

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