sealing device

Abstract

To provide a sealing device which suppresses an increase of torque, and is improved in a suppression effect of grease leakage with respect to grease which is sealed into an annular space.SOLUTION: A sealing device 10 which is attached to one member out of two members composed of an inside member and an outside member which relatively and coaxially rotate, in which a step part protruding to one member side is arranged at the other member, and which seals grease sealed into an annular space S which is formed between the two members, comprises: a core body 11 fit to one member; and an elastic member 12 adhering to the core body. The elastic member comprises a first lip 121 extending to a side opposite to the annular space side, and slide-contacting with the other member, and a second lip 122 extending to the annular space side. The second lip constitutes a first labyrinth R1 existing between a peripheral face of the step part and itself, and a second labyrinth R2 located at the annular space side with respect to the step part, and existing between a peripheral face of the other member and itself, and is a grease lip which does not contact with the other member and the step part.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a sealing device that seals an annular space between two members that are made up of an inner member and an outer member that rotate coaxially relative to each other. [Background technology]

[0002] For example, a bearing device for a wheel of an automobile or the like is equipped with a sealing device that seals in grease sealed in an annular space. In such a sealing device, a grease lip extending toward the annular space slides against a component, thereby preventing grease from entering the sealing device. Furthermore, a side lip extending away from the annular space slides against a component, thereby preventing muddy water and the like from the outer space from entering the annular space.

[0003] In such a sealing device, the grease lip and the side lip are in sliding contact with one of the members, which poses a problem of increased torque.

[0004] Therefore, in the following Patent Documents 1 and 2, in order to suppress grease leakage and torque increase, the grease lip faces the slinger member with a small gap between them, but is not in contact with it, thereby forming a labyrinth seal. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-187218 [Patent Document 2] Japanese Patent Application Laid-Open No. 2009-030631 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in sealing devices in which one labyrinth seal is formed between the grease lip and the slinger member, such as those described in Patent Documents 1 and 2, there is a risk that the grease may pass over the grease lip and reach the side lip. Because the side lip may contain a different type of grease from the grease sealed in the annular space, if the grease in the annular space reaches the side lip, the different types of grease may mix, resulting in a decrease in performance.

[0007] The present invention has been made in consideration of the above-mentioned situation, and aims to provide a sealing device that suppresses an increase in torque and improves the effect of suppressing grease leakage from grease sealed in an annular space. [Means for solving the problem]

[0008] In order to achieve the above object, the sealing device of the present invention is attached to one of two members consisting of an inner member and an outer member which rotate coaxially relative to one another, and the other member is provided with a step portion which protrudes towards the one member, and seals in grease sealed in an annular space formed between the two members, and comprises a core body fitted to the one member and an elastic member fixed to the core body, the elastic member comprises a first lip which extends to the side opposite to the annular space side and which is in sliding contact with the other member, and a second lip which extends towards the annular space, and the second lip has a first labyrinth which exists between the second lip and a circumferential surface of the step portion, and a second lip which is in sliding contact with the other member which is located on the annular space side of the step portion Around The grease slip forms a second labyrinth between the surface and the other member and is not in contact with the step portion. [Effects of the Invention]

[0009] Since the sealing device of the present invention has the above-described configuration, it is possible to suppress an increase in torque and improve the effect of suppressing grease leakage from the grease sealed in the annular space. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic vertical cross-sectional view showing an example of a bearing device to which a sealing device according to an embodiment of the present invention is attached. [Figure 2] 1, and is a schematic vertical cross-sectional view and an enlarged view of a main part of a sealing device according to one embodiment of the present invention. [Figure 3] 1 is a schematic vertical cross-sectional view showing a state in which a plurality of sealing devices according to an embodiment of the present invention are stacked. [Figure 4] 10A and 10B are a schematic vertical cross-sectional view and an enlarged view of a main part of a sealing device according to a modified example of an embodiment of the present invention; [Figure 5] 10A and 10B are a schematic vertical cross-sectional view and an enlarged view of a main part of a sealing device according to another modified example of an embodiment of the present invention. [Figure 6] 1A is a schematic vertical cross-sectional view showing a sealing device according to another embodiment of the present invention, and FIG. 1B is a schematic vertical cross-sectional view showing a modified example of FIG. 1A. [Figure 7] 10A and 10B are a schematic vertical cross-sectional view and an enlarged view of a main part of a sealing device according to still another embodiment of the present invention; [Figure 8] 1, and is a schematic vertical cross-sectional view and an enlarged view of a main part thereof, showing a sealing device according to still another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] 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 devices 10, 20 are attached to one of two members consisting of an inner member and an outer member that rotate coaxially relative to one another, and the other member is provided with a stepped portion that protrudes toward the one member, thereby sealing grease sealed in the annular space S formed between the two members. The sealing devices 10, 20 include a core body 11, 21 that is fitted into one of the members, and an elastic member 12, 22 that is fixed to the core body 11, 21. The elastic member 12, 22 includes a first lip 121, 221 that extends toward the opposite side to the annular space S and is in sliding contact with the other member, and a second lip 122, 222 that extends toward the annular space S. The second lip 122, 222 forms a first labyrinth R1 between itself and the circumferential surface of the stepped portion, and a second labyrinth R2 between itself and the circumferential surface of the other member that is located closer to the annular space S than the stepped portion. The second lips 122, 222 are grease lips that do not come into contact with the other member or the stepped portion. Details are provided below.

[0012] First Embodiment The first embodiment will be described with reference to FIGS. FIG. 1 shows a bearing device 1 that supports a wheel (not shown), which is a mechanical device, of an automobile so that it can rotate (axially rotate) around an axis L. This bearing device 1 is a hub bearing that rotatably supports the drive wheel of an automobile. The bearing device 1 is composed of an outer ring 2, which corresponds to the outer member fixed to the vehicle body (not shown), an inner ring 6 that includes a hub ring 4, which corresponds to the inner member, and two rows of rolling elements (balls) 3... interposed between the outer ring 2 and the inner ring 6. The inner ring 6 is composed of a hub ring 4 and an inner ring member 5, which is fitted integrally with the vehicle body side of the hub ring 4. A drive shaft 7 that connects to a drive source (drive transmission unit) (not shown) via a constant velocity joint 8 is coaxially spline-fitted to the hub ring 4. The drive shaft 7 is integrated with the hub ring 4 by a nut 7a to prevent it from coming off the hub ring 4. The inner ring 6 (hub ring 4 and inner ring member 5) is rotatable coaxially with the outer ring 2 about axis L. Between the outer ring 2 and inner ring 6, the rolling elements 3 are held by a retainer 3a, and are interposed such that the outer raceway 2a of the outer ring 2 and the inner raceway 4a, 5a of the hub ring 4 and inner ring member 5 can roll. The space between the outer ring 2 and inner ring 6, including the interposed portion of the rolling elements 3, forms an annular space S as a sealed annular space, and this annular space S is filled with a lubricant (e.g., grease) to facilitate smooth rolling of the rolling elements 3. The hub ring 4 has a cylindrical hub ring body 40 into which the drive shaft 7 is spline-fitted, a flange portion 41 formed by continuously expanding in diameter from one wheel-side end 40a of the hub ring body 40, and a hub flange 42 extending radially outward via the flange portion 41. A wheel is attached and fixed to the hub flange 42 with bolts 43 and nuts (not shown). In the following, the side facing the wheel in the axial direction (left side in FIG. 1) will be referred to as the wheel side, and the side facing the vehicle body (right side in FIG. 1) will be referred to as the vehicle body side. In each figure, the part of the elastic member 12 indicated by the two-dot chain line represents the original shape before deformation.

[0013] Sealing devices 10, 20 are installed between the outer ring 2 and the inner ring 6 at the end of the annular space S on the vehicle body side and the end on the wheel side. These sealing devices 10, 20 seal the annular space S, preventing foreign matter such as muddy water from entering the annular space S from the outer space, and also preventing lubricant such as grease filled in the annular space S from leaking out. The sealing device 10 shown in Figures 2 to 6 is installed at the end of the annular space S on the vehicle body side, and the sealing device 20 shown in Figure 7 is installed at the end of the annular space S on the wheel side.

[0014] Next, the components constituting the sealing device 10 of the first embodiment shown in Fig. 2, which is an enlarged view of the X portion in Fig. 1, will be described. In this embodiment, of the two components, an inner member and an outer member, which rotate coaxially relative to each other, the outer ring 2, which is the outer member, will be described as one of the components. In this embodiment, the other component includes the inner ring 6, which is the inner member, as well as a slinger member 9 fitted (externally fitted) to the outer peripheral surface 6a of the inner ring 6.

[0015] The sealing device 10 comprises a core body 11 fitted into the outer ring 2, which is one of the components, and an elastic member 12 fixed to the core body 11. The core body 11 is formed by pressing a steel plate such as SPCC or SUS. The core body 11 comprises a cylindrical portion 110 fitted (inside) into the inner circumferential surface 2b of the outer ring 2, and a disk portion 111 extending radially inward from an end 110a of the cylindrical portion 110 on the wheel side.

[0016] The elastic member 12 is made of an elastic material such as rubber, and is fixed integrally to the core body 11 via the seal base 120 by vulcanization molding. The seal base 120 is arranged so as to wrap around the inner diameter side end 111b of the disc portion 111 of the core body 11, and covers the vehicle body side surface 111a of the disc portion 111 and the inner circumferential surface 110b of the cylindrical portion 110, and is also arranged so as to wrap around the vehicle body side end 110c, and the elastic member 12 is fixed integrally to the core body 11.

[0017] The elastic member 12 has a seal base 120 and a first lip 121, a second lip 122, and a third lip 123 extending from the seal base 120. The first lip 121 is located on the outermost side and is disposed in a position closest to the outer space. The second lip 122 is located on the innermost side and is disposed in a position closest to the annular space S. The third lip 123 is disposed in a position between the first lip 121 and the second lip 122. The first lip 121 extends with a gradually increasing diameter toward the side opposite the annular space S (toward the vehicle body), and is formed so that its tip faces the outer diameter side. It is a side lip that slides (resilient contacts) with a surface 91c of a disc portion 91 of the slinger member 9 (described later) facing the annular space S. The third lip 123 is a radial lip that extends toward the opposite side from the annular space S (toward the vehicle body), has its tip facing the inner diameter side, and is in sliding contact (elastic contact) with the outer peripheral surface 90b of the first cylindrical portion 90 of the slinger member 9, which will be described later. On the other hand, the second lip 122 is a grease lip that extends toward the annular space S side (wheel side) and does not contact the outer peripheral surface 6a of the inner ring 6 (inner ring member 5) or the first cylindrical portion 90 of the slinger member 9, which is a stepped portion, which will be described later. The second lip 122 has a second lip base 122a that extends from the seal base 120 toward the annular space S side (wheel side). Furthermore, the second lip 122 has, on the inner diameter side of the second lip base 122a, a lip disc portion 122b extending from a part on the wheel side to the inner diameter side, and a lip cylindrical portion 122c extending from an inner diameter side end 122ba of the lip disc portion 122b to the annular space S side.

[0018] The elastic member 12 has an annular protrusion 124 that protrudes outward in a portion covering the outer peripheral surface 110d of the cylindrical portion 110 of the core body 11. This annular protrusion 124 is formed so as to be interposed in a compressed state between the inner peripheral surface 2b of the outer ring 2 and the outer peripheral surface 110d of the cylindrical portion 110 of the core body 11 when the core body 11 is fitted inside the outer ring 2. The annular protrusion 124 is interposed in a compressed state between the outer ring 2 and the outer peripheral surface 110d of the cylindrical portion 110 of the core body 11, thereby preventing muddy water and the like from entering the mating portion between the outer ring 2 and the core body 11, thereby inhibiting rust. Note that the dashed double-dashed line in the drawing shows the original shape of the annular protrusion 124 before compression.

[0019] Furthermore, the elastic member 12 is provided with a contact prevention protrusion 125 that extends toward the wheel from a portion of the seal base 120 that covers the inner diameter side of the wheel-side surface 111c of the disc portion 111 of the core body 11. As shown in Fig. 2, the longitudinal cross section of the contact prevention protrusion 125 gradually tapers toward the wheel side. A tip end 125a of the contact prevention protrusion is located closer to the annular space S than the lip cylindrical portion 122c of the second lip 122.

[0020] The sealing device 10 also includes a slinger member 9 including a first cylindrical portion 90 that forms a step by being fitted (externally fitted) onto the outer peripheral surface 6a of the inner ring 6, which is the other component, and a disk portion 91 that extends axially outward from the vehicle body-side end 90a of the first cylindrical portion 90. The slinger member 9 further includes a second cylindrical portion 92 that extends from the outer diameter-side end 91a of the disk portion 91 toward the wheel. A magnetic body 93, which is an annular member made of a magnetic material such as magnetic rubber, is fixed to the vehicle body-side surface 91b of the disk portion 91. The magnetic body 93 covers the entire vehicle body-side surface 91b of the disk portion 91 of the slinger member 9, covers the entire outer peripheral surface 92a of the second cylindrical portion 92, and wraps around to the wheel-side end 92b of the second cylindrical portion 92. The detection surface 93a of the magnetic body 93 is magnetized with north and south poles alternating in the circumferential direction. A magnetic sensor (not shown) is disposed opposite this detection surface 93a, and when the inner ring 6 rotates around the axis L, the magnetic sensor detects magnetic changes caused by the magnetic body 93. By detecting this magnetic change, data on the rotational state, such as the number of rotations of the wheel, can be obtained.

[0021] By fitting (externally fitting) the first cylindrical portion 90 of the slinger member 9 to the outer peripheral surface 6a of the inner ring 6, which is the other member, the bearing device 1 obtains the first cylindrical portion 90 of the slinger member 9 as a step portion protruding from the inner ring 6 to the outer diameter side (towards the outer ring 2, which is one of the members).

[0022] The sealing device 10 configured as described above is attached to the bearing device 1 by fitting (inner fitting) the cylindrical portion 110 of the core body 11 into the outer ring 2 and fitting (outer fitting) the first cylindrical portion 90 of the slinger member 9 into the inner ring 6. The second lip 122 is configured so as not to come into contact with the outer peripheral surface 90b and wheel-side end face 90c of the first cylindrical portion 90, which are the stepped portion, and the outer peripheral surface 6a of the inner ring 6. The second lip 122 forms three labyrinths between the inner ring 6, which is the other member, and the first cylindrical portion 90 of the slinger member 9, which is the stepped portion. The inner peripheral surface 122aa of the second lip base 122a of the second lip 122 is arranged substantially parallel to and facing the outer peripheral surface 90b of the first cylindrical portion 90 of the slinger member 9 with a gap provided therebetween, thereby forming a first labyrinth R1 extending in the axial direction. A third labyrinth R3 extending in the radial direction is formed by arranging a vehicle body side surface 122bb of the lip disc portion 122b of the second lip 122 facing and generally parallel to the wheel side end face 90c of the first cylindrical portion 90 of the slinger member 9 with a gap provided therebetween. An inner peripheral surface 122ca of the lip cylindrical portion 122c of the second lip 122 facing and generally parallel to the outer peripheral surface 6a of the inner ring 6 with a gap provided therebetween, thereby forming a second labyrinth R2 extending in the axial direction.

[0023] The gap widths r1, r2, and r3 of the first, second, and third labyrinths R1, R2, and R3 are each between approximately 0.1 and 0.5 mm. The gap widths r1, r2, and r3 of the first, second, and third labyrinths R1, R2, and R3 are set to be approximately the same. If the gap widths r1, r2, and r3 are less than 0.1 mm, it is difficult to form a labyrinth gap. If they are greater than 0.5 mm, muddy water and the like tend to easily infiltrate. According to this embodiment, the second lip 122 does not contact other components through such small gaps, thereby suppressing an increase in torque. Furthermore, by connecting the axially extending first labyrinth R1, the radially extending third labyrinth R3, and the axially extending second labyrinth R2, a multiple labyrinth structure can be formed by utilizing the stepped portion, the first cylindrical portion 90 of the slinger member 9. The labyrinth structure and the width dimension of the labyrinth gap make it difficult for the grease filling the annular space S to reach the tip of the third lip 123, improving the grease leakage prevention performance of the sealing device 10. Even if the grease does reach the tip of the third lip 123, the labyrinth structure and the width dimension of the labyrinth gap described above can delay the time it takes for the grease to reach the tip, improving the sealing performance. Furthermore, because the grease filling the annular space S is difficult to reach the third lip 123, it is possible to prevent the grease filling the annular space S from mixing with the lip grease applied to the tip of the third lip 123. Furthermore, the lip cylindrical portion 122c configures the axial dimension l2 of the second labyrinth R2 closest to the annular space S to be larger than the axial dimension l1 of the first labyrinth R1. The second labyrinth R2 located on the annular space S side has a large axial dimension l2, which further suppresses the intrusion of grease. The axial dimension l2 of the second labyrinth R2 is configured to be larger than the axial dimension l1 of the first labyrinth R1 and the radial dimension l3 of the third labyrinth R3. The radial dimension l3 of the third labyrinth R3 is configured to be larger than the axial dimension l1 of the first labyrinth R1.

[0024] As described above, the second lip 122 is a non-contact grease lip, which suppresses an increase in torque of the sealing device 10. Furthermore, as described above, three labyrinths are formed between the second lip 122 and the first cylindrical portion 90 of the slinger member 9, which is the stepped portion, and the outer peripheral surface 6a of the inner ring 6. By forming three labyrinths, the sealing device 10 according to this embodiment has improved grease leakage prevention performance and sealing performance compared to a device having only one labyrinth.

[0025] Furthermore, the elastic member 12 is provided with an annular contact prevention protrusion 125 having a tip portion 125a that is located closer to the annular space S than the second lip 122. As shown in Fig. 3, when stacking multiple sealing devices 10, the multiple sealing devices 10 are stacked so that the tip portion 125a of the contact prevention protrusion 125 facing downward comes into contact with the detection surface 93a of the magnetic body 93 of another sealing device 10. When multiple sealing devices are stacked in this manner, the tip portion 125a of the contact prevention protrusion 125 comes into contact with the detection surface 93a of the magnetic body 93, so that the second lip 122 is prevented from coming into contact with other members, and deformation of the second lip 122 and adhesion to other devices can be prevented.

[0026] Furthermore, the sealing device 10 has a labyrinth R4 extending in the axial direction between the seal base 120 fixed to the inner peripheral surface 110b of the cylindrical portion 110 of the core body 11 and the magnetic body 93 fixed to the outer peripheral surface 92a of the second cylindrical portion 92 of the slinger member 9. The disc portion 91 of the slinger member 9 and the labyrinth R4 prevent foreign matter such as muddy water from entering the sealing device 10 from the outer space.

[0027] Next, modified examples and other embodiments of the sealing device 10 will be described with reference to the drawings. Note that a description of the configuration, effects, etc. of parts common to the sealing device 10 of the first embodiment described above will be omitted.

[0028] <Modification of the first embodiment> The sealing device 10' shown in Fig. 4 is a modified example of the sealing device 10 according to the first embodiment shown in Fig. 2. The sealing device 10' in Fig. 4 is different from the sealing device 10 of the first embodiment in the configuration of the elastic member 12, in particular the configuration of the second lip 122, but the other configurations are substantially the same. The second lip 122 includes a second lip base 122a extending from the seal base 120 toward the wheel, and a lip disk portion 122b extending from a portion of the wheel side on the inner diameter side of the second lip base 122a toward the inner diameter side. The sealing device 10′ shown in FIG. 4 differs from the sealing device 10 of the first embodiment in that the second lip 122 does not include a lip cylindrical portion 122c. Even without the lip cylindrical portion 122c, the inner diameter side end face 122bc of the lip disk portion 122b is disposed substantially parallel to and facing the outer peripheral surface 6a of the inner ring 6 with a gap therebetween, thereby forming a second labyrinth R2 extending in the axial direction. As described above, even without the lip cylindrical portion 122c, the second labyrinth R2 can be formed by the inner diameter side end face 122bc of the lip disk portion 122b. As in the first embodiment, an inner peripheral surface 122aa of a second lip base portion 122a of the second lip 122 is disposed substantially parallel to and facing an outer peripheral surface 90b of the first cylindrical portion 90 of the slinger member 9 with a gap therebetween, thereby forming a first labyrinth R1 extending in the axial direction. Also, as in the first embodiment, a vehicle body side surface 122bb of a lip disc portion 122b of the second lip 122 is disposed substantially parallel to and facing an end surface 90c of the first cylindrical portion 90 of the slinger member 9 with a gap therebetween, thereby forming a third labyrinth R3 extending in the radial direction. As in the first embodiment, width dimensions r1, r2, r3 of the gaps between the first, second, and third labyrinths R1, R2, and R3 are each configured to be between approximately 0.1 and 0.5 mm. The width dimensions r1, r2, and r3 of the gaps between the first, second, and third labyrinths R1, R2, and R3 are set to be approximately the same dimensions, as in the first embodiment. Unlike the first embodiment, the axial dimension l2 of the second labyrinth R2 is configured to be smaller than the axial dimension l2 of the first labyrinth R1 and the radial dimension l3 of the third labyrinth R3. Even if the axial dimension l3 of the third labyrinth R3 is small, the labyrinth structure formed by the first, second, and third labyrinths R1, R2, and R3 allows the sealing device 10' to have grease leakage prevention performance and sealing performance.

[0029] The sealing device 10'' shown in Fig. 5 is a modified example of the sealing device 10 according to the first embodiment shown in Fig. 2. The sealing device 10'' in Fig. 5 is different from the sealing device 10 of the first embodiment in the configuration of the elastic member 12, in particular the configuration of the second lip 122, but the other configurations are substantially the same. The second lip 122 includes, on the inner diameter side of the second lip base 122a, a lip disk portion 122b extending from a part on the annular space S side to the inner diameter side, and a lip cylindrical portion 122c extending from an end portion 122ba on the inner diameter side of the lip disk portion 122b to the side opposite the annular space S. That is, in the sealing device 10'' of this embodiment, the axial extension direction of the lip cylindrical portion 122c of the second lip 122 is opposite to the axial direction compared to the lip cylindrical portion 122c of the first embodiment. A vehicle body side end face 122cb of the lip cylindrical portion 122c is disposed substantially parallel to and facing the wheel side end face 90c of the first cylindrical portion 90 of the slinger member 9 with a gap provided therebetween, thereby forming a third labyrinth R3. A gap space 126 is defined between an inner peripheral surface 122aa of the second lip base 122a and an outer peripheral surface 122cc of the lip cylindrical portion 122c. The outer peripheral surface 122cc of the lip cylindrical portion 122c is configured to be located radially inward relative to an outer peripheral surface 90b of the first cylindrical portion 90 of the slinger member 9. Even if grease filling the annular space S reaches the third labyrinth R3, it is likely to flow along the outer peripheral surface 122cc of the lip cylindrical portion 122c and accumulate in the space 126, thereby reducing the amount of grease heading toward the first labyrinth R1. As in the first embodiment, the inner peripheral surface 122aa of the second lip base 122a of the second lip 122 faces and is disposed substantially parallel to the outer peripheral surface 90b of the first cylindrical portion 90 of the slinger member 9 with a gap therebetween, thereby defining the first labyrinth R1 extending in the axial direction. Also, as in the first embodiment, the inner surface 122ca of the lip cylindrical portion 122c of the second lip 122 is arranged opposite and approximately parallel to the outer surface 6a of the inner ring 6 with a gap provided, thereby forming a second labyrinth R2 extending in the axial direction.

[0030] Second Embodiment Next, a sealing device 10A according to a second embodiment shown in Fig. 6(a) and a sealing device 10A' shown in Fig. 6(b) will be described. Note that a description of the configuration and effects common to the sealing device 10 of the first embodiment shown in Fig. 2 will be omitted. In Fig. 6(a), the configuration of the elastic member 12 differs from that of the first embodiment in that it does not include a third lip 123 and that the second lip 122 does not cooperate with the slinger 9 to form the third labyrinth R3. In Fig. 6(b), it also differs from that of the first embodiment in that the slinger member 9 does not include a magnetic body 93.

[0031] 6(a) has a first lip 121 and a second lip 122 extending from a seal base 120. The elastic member 12 of this embodiment does not have a third lip 123, which is a radial lip that comes into sliding contact (elastic contact) with the outer peripheral surface 90b of the first cylindrical portion 90 of the slinger member 9, which the elastic member 12 of the first embodiment has.

[0032] The first lip 121 is generally identical to that in the first embodiment in that it gradually widens in diameter and extends toward the side opposite the annular space S (toward the vehicle body), with its tip facing the outer diameter side, and is a side lip that makes sliding contact (elastic contact) with the surface 91c of the disc portion 91 of the slinger member 9 on the annular space S side.

[0033] The second lip 122 is a grease lip that does not contact the first cylindrical portion 90 of the slinger member 9. The second lip 122 is disposed such that an inner peripheral surface 122aa of the second lip base 122a faces the outer peripheral surface 90b of the first cylindrical portion 90 of the slinger member 9 with a gap provided therebetween, thereby forming a first labyrinth R1 that extends in the axial direction. The inner peripheral surface 122aa of the second lip base 122a is configured to be inclined toward the inner diameter side so that its diameter gradually decreases toward the annular space S side. Therefore, the first labyrinth R1 is configured to be inclined so that the width dimension of the gap gradually decreases from r1 to r1' toward the annular space S side.

[0034] The second lip 122 also has a protruding portion 122d that protrudes radially inward from an inner circumferential surface 122aa of the second lip base 122a. The protruding portion 122d is configured so that a surface 122da on the opposite side to the annular space S is inclined radially inward so that the diameter gradually decreases toward the annular space S. Therefore, unlike the first embodiment, the second lip 122 does not form a third labyrinth R3 between itself and the wheel-side end surface 90c of the first cylindrical portion 90 of the slinger member 9.

[0035] The second lip 122 defines a second labyrinth R2 extending in the axial direction by arranging the inner peripheral surface 122db of the protruding portion 122d facing and substantially parallel to the outer peripheral surface 6a of the inner ring 6 with a gap provided therebetween. Note that in Figures 6(a) and 6(b), the second labyrinth R2 is configured so that the axial dimension l2 is smaller than the axial dimension l1 of the first labyrinth R1, but the second labyrinth R2 may be configured so that the axial dimension l2 is larger than the axial dimension l1 of the first labyrinth R1.

[0036] Furthermore, a surface 122ab of the second lip base 122a facing the annular space S is configured along the radial direction, and a surface 122dc of the protruding portion 122d facing the annular space S is configured along the radial direction. The surface 122ab of the second lip base 122a facing the annular space S and the surface 122dc of the protruding portion 122d facing the annular space S are configured to be flush with each other to form a flat surface portion 127. The flat surface portion 127 is provided to protrude further toward the annular space S than the core body 11. Therefore, as in the sealing device 10 of the first embodiment shown in FIG. 3, by facing the flat surface portion 127 downward, multiple sealing devices 10A can be stacked in a stably state.

[0037] In the sealing device 10A of the second embodiment, similarly to the sealing device 10 of the first embodiment, a labyrinth R4 extending in the axial direction is formed between the seal base 120 fixed to the inner peripheral surface 110b side of the cylindrical portion 110 of the core body 11 and the magnetic body 93 fixed to the outer peripheral surface 92a of the second cylindrical portion 92 of the slinger member 9. The disc portion 91 of the slinger member 9 and the labyrinth R4 prevent foreign matter such as muddy water from the outer space from entering the sealing device 10. Moreover, unlike the sealing device 10 of the first embodiment, the sealing device 10A is configured not to have a third labyrinth R3, and first and second labyrinths R1 and R2 are formed between the second lip 122 and the stepped portion, which is the first cylindrical portion 90 of the slinger member 9 or the outer peripheral surface 6a of the inner ring 6. Even with this configuration, the labyrinth R4 prevents foreign matter such as muddy water from entering the sealing device 10 from the outer space, and even if the foreign matter passes through the labyrinth R4, the first lip 121, the first labyrinth R1, and the second labyrinth R2 slow down the speed at which the foreign matter enters, making it easier for the foreign matter to be expelled to the outside of the sealing device 10A by the centrifugal force generated by driving the bearing device 1. In addition, the second lip 122 is a non-contact grease lip, and the first lip 121 is the only lip that comes into sliding contact with the slinger 9, so the sealing device 10A can be made low torque.

[0038] Furthermore, as in the first embodiment, a magnetic body 93 is fixed to the slinger 9, so if a magnetic sensor is placed opposite the magnetic body 93, the magnetic changes caused by the magnetic body 93 can be detected by the magnetic sensor, and data on the rotational state, such as the wheel rotation speed, can be obtained.

[0039] <Modification of the second embodiment> Next, a sealing device 10A' that is a modified example of the sealing device 10A of the second embodiment will be described with reference to Fig. 6(b). Note that a description of the configuration and effects of parts common to the sealing device 10A will be omitted.

[0040] In the sealing device 10A', the slinger 9 does not have a magnetic material 93, and a labyrinth R4 extending axially is formed between the seal base 120 fixed to the inner surface 110b of the cylindrical portion 110 of the core body 11 and the outer surface 92a of the second cylindrical portion 92 of the slinger 9.

[0041] Further, the second lip 122 of the sealing device 10A' is the same as that of the sealing device 10A in that it does not form a third labyrinth R3 between itself and the inner ring 6. Further, the second lip 122 of the sealing device 10A' is the same as that of the sealing device 10A in that it forms a first labyrinth R1 between itself and the first cylindrical portion 90 of the slinger 9, and that a protruding portion 122d protruding from the second lip base portion 122a toward the inner diameter side forms a second labyrinth R2 between itself and the inner ring 6. The sealing device 10A' differs from the sealing device 10A in that a surface 122ab of the second lip base portion 122a facing the annular space S is inclined toward the inner diameter side so as to gradually decrease in diameter toward the annular space S. Therefore, the sealing device 10A' does not have the flat surface portion 127 that the sealing device 10A has in FIG. 6(a).

[0042] In the sealing device 10A' of FIG. 6(b), the slinger 9 does not include a magnetic body 93, and the elastic member 12 does not include a flat surface portion 127. However, the sealing device 10A' includes a first lip 121 that slides against the slinger 9 and a second lip 122 that is a non-contact grease lip. Furthermore, a labyrinth R4 extends in the axial direction between the seal base 120 fixed to the inner peripheral surface 110b of the cylindrical portion 110 of the core body 11 and the outer peripheral surface 92a of the second cylindrical portion 92 of the slinger 9, and first and second labyrinths R1 and R2 are formed between the second lip 122 and the stepped portion, i.e., the first cylindrical portion 90 of the slinger member 9 or the outer peripheral surface 6a of the inner ring 6. Therefore, the sealing device 10A' of FIG. 6(b) has substantially the same sealing performance as the sealing device 10A of FIG. 6(a). 。

[0043] Third Embodiment Next, a sealing device 10B according to a third embodiment shown in FIG. 7 will be described. 7, the configuration of the bearing device 1 differs from that of the first embodiment in the configuration of the inner ring 6. The inner ring member 5, which constitutes the inner ring 6 together with the hub ring 4, has a protruding portion 60 that forms a step portion in which a portion of the outer peripheral surface 6a on the side opposite to the annular space S protrudes outward.

[0044] Next, each member constituting the sealing device 10B will be described. The sealing device 10B includes a core body 11 and an elastic member 12 fixed to the core body 11. In this embodiment, unlike the first embodiment, the sealing device 10B does not include a slinger member. The core body 11 is formed by pressing a steel plate such as SPCC or SUS. The core body 11 includes a cylindrical portion 110 that is fitted (inside fitted) into the outer ring 2, and a disk portion 111 that extends radially inward from an end portion 110c of the cylindrical portion 110 that is opposite the annular space S. An end portion 110a of the cylindrical portion 110 of the core body 11 that is on the annular space S side is located closer to the annular space S than a second lip 122 of the elastic member 12, which will be described later.

[0045] The elastic member 12 is made of an elastic material such as rubber, and is fixed integrally to the core body 11 by vulcanization molding via the seal base 120. The seal base 120 covers the inner diameter side surface of the wheel-side surface 111c of the disc portion 111 of the core body 11, wraps around the inner diameter side end portion 111b of the disc portion 111, and covers the entire surface 111a of the disc portion 111 on the opposite side to the annular space S.

[0046] The elastic member 12 includes a first lip 121 extending toward the opposite side from the annular space S, and a second lip 122 extending toward the annular space S. The first lip 121 is a radial lip formed such that its tip faces the inner diameter side and is in sliding (elastic) contact with the outer peripheral surface 60a of the protruding portion 60 of the inner ring 6. On the other hand, the second lip 122 is a grease lip that does not contact the outer peripheral surface 6a of the inner ring 6 or the protruding portion 60. The second lip 122 includes a second lip base 122a extending toward the inner diameter side from the seal base 120. Furthermore, the second lip 122 includes, on the inner diameter side of the second lip base 122a, a lip disk portion 122b extending toward the inner diameter side from a part on the annular space S side, and a lip cylindrical portion 122c extending toward the annular space S from an end portion 122ba on the inner diameter side of the lip disk portion 122b.

[0047] The elastic member 12 has an annular protrusion 124 that protrudes outward in a portion extending to the outermost diameter side of the disc portion 111 of the core body 11. This annular protrusion 124 is formed so as to be interposed in a compressed state between the inner circumferential surface 2b of the outer ring 2 and the disc portion 111 of the core body 11 when the core body 11 is fitted inside the outer ring 2. By interposing the annular protrusion 124 in a compressed state between the outer ring 2 and the disc portion 111 of the core body 11, it is possible to prevent muddy water and the like from entering the mating portion between the outer ring 2 and the core body 11, thereby inhibiting rust. Note that in the drawing, the dashed dotted line portion of the annular protrusion 124 indicates its original shape before compression.

[0048] In this embodiment, the end 110a of the cylindrical portion 110 of the core body 11 on the annular space S side is located closer to the annular space S than the second lip 122 of the elastic member 12. Therefore, the elastic member 12 does not have the contact prevention protrusion 125 as in the first embodiment. When multiple sealing devices 10A are stacked as in FIG. 3, the cylindrical portion 110 of the core body 11 exerts the same effect as the contact prevention protrusion 125 in the first embodiment, and prevents the second lip 122 of the elastic member 12 from contacting the components of the other sealing devices 10A.

[0049] The second lip 122 of the elastic member 12 forms three labyrinths between the inner ring 6, which is the other member, and the protruding portion 60, which is the stepped portion. An inner peripheral surface 122aa of the second lip base 122a is disposed facing and approximately parallel to the outer peripheral surface 60a of the protruding portion 60 of the inner ring 6 with a gap provided, thereby forming a first labyrinth R1 extending in the axial direction. An inner peripheral surface 122ca of the lip cylindrical portion 122c of the second lip 122 is disposed facing and approximately parallel to the outer peripheral surface 6a of the inner ring 6 with a gap provided, thereby forming a second labyrinth R2 extending in the axial direction. Finally, a vehicle body side surface 122bb of the lip disc portion 122b of the second lip 122 is disposed facing and approximately parallel to the wheel side end face 60b of the protruding portion 60 with a gap provided, thereby forming a third labyrinth R3 extending in the radial direction.

[0050] The first, second, and third labyrinths R1, R2, and R3 are connected to each other, and labyrinths extending in the axial, radial, and axial directions are continuous. The sealing device 10A can configure multiple labyrinth structures by utilizing the protrusion 60, which is a stepped portion. This makes it difficult for the grease filling the annular space S to reach the tip of the first lip 121, improving grease leakage prevention performance. Even if the grease does reach the tip of the first lip 121, the labyrinth structure and the width of the labyrinth gap described above can delay the time it takes for the grease to reach the tip, improving sealing performance. Furthermore, because the grease filling the annular space S is difficult to reach the first lip 121, mixing of the grease filling the annular space S with the lip grease applied to the tip of the first lip 121 is suppressed. Similarly to the first embodiment, the axial dimension l2 of the second labyrinth R2 is configured to be larger than the axial dimension l1 of the first labyrinth R1 and the radial dimension l3 of the third labyrinth R3. The larger axial dimension l2 of the second labyrinth R2 located on the annular space S side further suppresses the intrusion of grease.

[0051] As described above, the second lip 122 is a non-contact grease lip that does not come into contact with the outer peripheral surface 6a of the inner ring 6 or the protruding portion 60, and therefore an increase in torque is suppressed. Also, as described above, three labyrinths are formed between the second lip 122 and the protruding portion 60, which is a step portion, and the outer peripheral surface 6a of the inner ring 6. By forming three labyrinths, the sealing device 10A has improved grease leakage prevention performance and sealing performance compared to conventional sealing devices that are formed with only one labyrinth.

[0052] <Fourth embodiment> Next, a sealing device 20 according to a fourth embodiment shown in FIG. 8, which is an enlarged view of a portion Y in FIG. 1, will be described. The sealing device 20 according to the fourth embodiment is different from the sealing devices 10, 10A, and 10B according to the first, second, and third embodiments, and is attached to the end of the annular space S on the wheel side. The sealing device 20 includes a core body 21 and an elastic member 22 fixed to the core body 21 . The core body 21 is formed by pressing a steel plate such as SPCC or SUS. The core body 21 includes a cylindrical portion 210 that is fitted (inside fitted) into the outer ring 2, and a disk portion 211 that extends radially inward from an end 210a of the cylindrical portion 210 that is on the wheel side. Note that an end 210b of the cylindrical portion 210 of the core body 21 that is on the vehicle body side is located closer to the vehicle body than a second lip 222 of the elastic member 22, which will be described later.

[0053] The elastic member 22 is made of an elastic material such as rubber, and is fixed integrally to the core body 21 by vulcanization molding. The elastic member 22 has a seal base 220 that covers the inner diameter side of the vehicle body side surface 211a of the disc portion 211 of the core body 21, wraps around the inner diameter side end portion 211b of the disc portion 211, and covers the entire wheel side surface 211c of the disc portion 211.

[0054] The elastic member 22 has a first lip 221 that extends from the seal base 220, is located on the outermost side, and is positioned close to the outer space. The elastic member 22 also has a second lip 222 that extends from the seal base 220, is located on the innermost side, and is positioned close to the annular space S, and a third lip 223 that extends from the seal base 220 and is positioned between the first lip 221 and the second lip 222. Note that, unlike the first, second, and third embodiments, in this embodiment, the annular space S side is the vehicle body side, and the opposite side to the annular space S side is the wheel side. The first lip 221 extends with a gradually increasing diameter toward the side opposite the annular space S (the wheel side), with its tip facing the outer diameter side. This is a side lip that comes into sliding (elastic) contact with a surface 91Aa of a disc portion 91A of the slinger member 9A (described later) that faces the annular space S. The third lip 223 extends toward the opposite side from the annular space S (toward the wheel), with its tip facing the outer diameter side, and is a side lip that comes into sliding contact (elastic contact) with a surface 91Aa of a disk portion 91A of the slinger member 9A (described later) that faces the annular space S. The second lip 222 includes a second lip base 222a that extends from the seal base 220 toward the annular space S (toward the vehicle body). Furthermore, the second lip 222 includes, on the inner diameter side of the second lip base 222a, a lip disk portion 222b that extends toward the inner diameter side from a part on the vehicle body side, and a lip cylindrical portion 222c that extends toward the vehicle body from an end 222ba on the inner diameter side of the lip disk portion 222b.

[0055] The elastic member 22 has an annular protrusion 224 that protrudes outward in a portion extending to the outermost diameter side of the disc portion 211 of the core body 21. This annular protrusion 224 is formed so as to be interposed in a compressed state between the inner circumferential surface 2b of the outer ring 2 and the disc portion 211 of the core body 21 when the core body 21 is fitted inside the outer ring 2. The annular protrusion 224 is interposed in a compressed state between the outer ring 2 and the disc portion 211 of the core body 21, thereby preventing muddy water and the like from entering the mating portion between the outer ring 2 and the core body 21 and inhibiting rust. Note that in the drawing, the dashed dotted line portion of the annular protrusion 224 indicates its original shape before compression.

[0056] In this embodiment, the end 210b of the cylindrical portion 210 of the core body 21 on the annular space S side is located closer to the annular space S than the second lip 222 of the elastic member 22, and therefore the elastic member 22 does not have a contact prevention protrusion as in the first embodiment. When a plurality of sealing devices 20 are stacked as in FIG. 3, the cylindrical portion 210 of the core body 21 exerts the same effect as the contact prevention protrusion 125 in the first embodiment, and prevents the second lip 222 of the elastic member 22 from contacting the members of the other sealing device 20.

[0057] The sealing device 20 is equipped with a slinger member 9A including a cylindrical portion 90A that fits onto the outer peripheral surface 6a of the inner ring 6, which is the other member, and that forms a step portion, and a disk portion 91A that extends axially outward from an end 90Aa of the cylindrical portion 90A on the wheel side. A surface 91Ab of the disk portion 91A of the slinger member 9A opposite to the annular space S abuts against a surface 41a of the flange portion 41 of the hub wheel 4 that faces the annular space S. By fitting the cylindrical portion 90A of the slinger member 9A onto the outer peripheral surface 60a of the inner ring 6, the bearing device 1 obtains the cylindrical portion 90A of the slinger member 9A as a step portion that protrudes toward one member (outer ring 2).

[0058] The sealing device 20 configured as described above is attached to the bearing device 1 by fitting (inner fitting) the cylindrical portion 210 of the core 21 into the outer ring 2 and fitting (outer fitting) the cylindrical portion 90A of the slinger member 9A into the inner ring 6. The second lip 222 is configured so as not to come into contact with the stepped portion, i.e., the cylindrical portion 90A of the slinger member 9A, or the outer peripheral surface 6a of the inner ring 6. The second lip 222 forms three labyrinths between itself and the cylindrical portion 90A of the slinger member 9A and the outer peripheral surface 6a of the inner ring 6. The inner peripheral surface 222aa of the second lip base 222a is disposed substantially parallel to and opposite the outer peripheral surface 90Ab of the cylindrical portion 90A of the slinger member 9A with a gap provided therebetween, thereby forming a first labyrinth R1 extending in the axial direction. A wheel-side surface 222bb of the lip disc portion 222b of the second lip 222 is disposed substantially parallel to and facing the vehicle body-side end face 90Ac of the cylindrical portion 90A of the slinger member 9A with a gap therebetween, thereby forming a radially extending third labyrinth R3. An inner peripheral surface 222ca of the lip cylindrical portion 222c of the second lip 122 is disposed substantially parallel to and facing the outer peripheral surface 6a of the inner ring 6 with a gap therebetween, thereby forming an axially extending second labyrinth R2.

[0059] The first labyrinth R1 extending in the axial direction, the third labyrinth R3 extending in the radial direction, and the second labyrinth R2 extending in the axial direction are connected to each other, thereby utilizing the cylindrical portion 90A that forms the stepped portion to form a multiple labyrinth structure. The multiple labyrinths make it difficult for the grease filling the annular space S to reach the tip of the third lip 223, improving grease leakage prevention. Even if the grease does reach the tip of the third lip 223, the labyrinth structure and the width of the labyrinth gap described above can delay the time it takes for the grease to reach the tip, thereby improving sealing performance. Furthermore, because the grease filling the annular space S is difficult to reach the third lip 223, mixing of the grease filling the annular space S with the lip grease applied to the tip of the third lip 223 is suppressed. Similarly to the first and second embodiments, the axial dimension l2 of the second labyrinth R2 is configured to be larger than the axial dimension l1 of the first labyrinth R1 and the radial dimension l3 of the third labyrinth R3. The larger axial dimension l2 of the second labyrinth R2 located on the annular space S side further suppresses the intrusion of grease.

[0060] As described above, the second lip 222 is a non-contact grease lip, so an increase in torque is suppressed. Furthermore, three labyrinths are formed between the second lip 222 and the stepped portion, i.e., the cylindrical portion 90A of the slinger member 9A and the outer peripheral surface 6a of the inner ring 6. By forming three labyrinths, the sealing device 20 according to this embodiment has improved sealing performance and grease leakage prevention performance compared to a device having only one labyrinth. Furthermore, even if foreign matter such as muddy water enters from the outer space, the first lip 221 and the third lip 223, which are in sliding contact with the surface 91Aa of the disc portion 91A of the slinger member 9A facing the annular space S, prevent the foreign matter from reaching the second lip 222.

[0061] The configurations of the first, second, and third labyrinths R1, R2, and R3 are not limited to those described in the above-described embodiments, and the width r1 of the first labyrinth R1, the width r2 of the second labyrinth R2, and the width r3 of the third labyrinth R3 may be changed as appropriate. For example, the relationship may be changed so that the width r1 of the first labyrinth R1 is larger than the width r3 of the third labyrinth R3, and the width r3 of the third labyrinth R3 is larger than the width r2 of the second labyrinth R2. Also, the relationship may be changed so that the width r1 of the first labyrinth R1 is smaller than the width r3 of the third labyrinth R3, and the width r3 of the third labyrinth R3 is smaller than the width r2 of the second labyrinth R2. The axial dimension l1 of the first labyrinth R1, the radial dimension l3 of the third labyrinth R3, and the axial dimension l2 of the second labyrinth R2 may be changed as appropriate. For example, the axial dimension l1 of the first labyrinth R1 may be configured to be larger than the radial dimension l3 of the third labyrinth R3 and the axial dimension l2 of the second labyrinth R2. Furthermore, the radial dimension l3 of the third labyrinth R3 may be configured to be larger than the axial dimension l2 of the second labyrinth R2.

[0062] It should be noted that the sealing devices 10, 10', 10'', 10A, 10A', 10B, and 20 of the above-described embodiments are not limited to the shapes and configurations shown in the drawings. For example, the core bodies 11 and 21 may be made of other metal materials, resin materials, etc., instead of steel plates such as SPCC or SUS. Similarly, the slinger members 9 and 9A may be made of other metal materials, resin materials, etc., instead of steel plates such as SPCC or SUS. Furthermore, the shapes and number of the lips provided on the elastic members 12 and 22 are not limited to the shapes and configurations shown in the drawings. [Explanation of symbols]

[0063] 1 Bearing device 2 Outer ring (outer member) 4 Hub wheels 5 Inner ring member 6 Inner ring (inner member) 6a Outer surface 60 Protrusion (step) 60a outer surface 60b end face 10,20 Sealing device 11,21 Core 12,22 Elastic member 121,221 First Lip 122,222 Second Lip 122c, 222c Cylindrical lip part 9 Slinger member 90 First cylindrical part (step part) 90b Outer surface 90c end face 91 Disc 9A Slinger member 90A Cylindrical part (step part) 90Ab outer surface 90Ac end face 91A Disc L axis R1 First Labyrinth R2 Second Labyrinth R3 3rd Labyrinth S Annular Space

Claims

1. A sealing device that is attached to one of two members consisting of an inner member and an outer member that rotate coaxially relative to one another, and that has a step portion that protrudes toward the one member on the other member, and that seals in grease sealed in an annular space formed between the two members, a core body fitted to the one member, and an elastic member fixed to the core body, the elastic member includes a first lip extending toward the opposite side to the annular space and in sliding contact with the other member, and a second lip extending toward the annular space, a second lip that forms a first labyrinth between itself and the peripheral surface of the stepped portion, and a second labyrinth that forms between itself and the peripheral surface of the other member that is located closer to the annular space than the stepped portion, and that is a grease lip that does not contact the other member or the stepped portion.

2. In claim 1, A sealing device, wherein the second labyrinth has an axial dimension larger than that of the first labyrinth.

3. In claim 1 or 2, The second lip is formed to extend toward the other member in the radial direction, A sealing device characterized in that the second labyrinth is formed by the end of the second lip on the other member side and the peripheral surface of the other member.

4. In claim 3 the second lip includes a lip cylindrical portion extending in the axial direction from an end portion of the second lip on the other member side, The sealing device is characterized in that the second labyrinth is formed by the peripheral surface of the lip cylindrical portion on the other member side and the peripheral surface of the other member.

5. In any one of claims 1 to 4, A sealing device characterized in that the second lip exists between the step portion and the end face of the annular space side, and forms a third labyrinth that communicates with the first labyrinth and the second labyrinth.

6. In any one of claims 1 to 5, a slinger member including a cylindrical portion that is fitted to the peripheral surface of the other member and that forms the step portion at one end in the axial direction, and a disk portion that extends radially from the other end in the axial direction of the cylindrical portion, A sealing device characterized in that the first lip is in sliding contact with the disc portion of the slinger member.

Images