Combined seal ring and hub unit bearing comprising combined seal ring

Abstract

To provide a combined seal ring capable of suppressing increase of seal torque and having excellent sealability, and a long-life hub unit bearing comprising the combined seal ring.SOLUTION: A slinger 51A of a combined seal ring 50A has a cylindrical part 52 fixed to an outer peripheral surface of an inward member 33, and a circular ring part 53 extending radially outward from one end part of the cylindrical part 52. A seal ring 61A comprises a core metal 62 having a core metal cylindrical part 64 fixed to the inner peripheral surface of an outward member 20 and a core metal circular ring part 65 extending radially inward from the other end part of the core metal cylindrical part 64, and a seal part 63 having seal lips 68, 69 that is brought into slide contact with the slinger 51A. The portion of the core metal circular ring part 65 close to the outer diameter is provided continuously in a circumferential direction, and has a low rigidity region 90 with lower rigidity than the surroundings.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a combination seal ring and a hub unit bearing equipped with the combination seal ring. [Background technology]

[0002] Hub unit bearings, which support the wheels of automobiles to rotate freely relative to the suspension system, are used in environments where they are directly exposed to muddy water, so they require high-grade sealing performance. On the other hand, it is also required that the rotational torque of hub unit bearings be kept low in order to reduce fuel consumption of automobiles.

[0003] Hub unit bearings support a hub, to which a wheel is fixed, rotatably via multiple rolling elements inside an outer ring supported by a suspension system. A lubricant such as grease is sealed in the internal space in which the rolling elements are installed, and the opening of the internal space is closed with a sealing member. For this reason, the performance of the sealing member has a large impact on the performance required of the hub unit bearing, such as sealing performance and low torque.

[0004] 8, Patent Document 1 discloses a combination seal ring 100 including a seal ring 110 having a generally L-shaped cross section, with a core metal cylindrical portion 111 and a core metal circular ring portion 112 extending from the core metal cylindrical portion 111 to the inner diameter side, and fixed to the inner peripheral surface of an outer ring 101, and a slinger 120 (including an encoder) having a generally U-shaped cross section, with a cylindrical portion 121, a circular ring portion 122 extending from the cylindrical portion 121 to the outer diameter side, and an outer diameter side cylindrical portion 123, and fixed to the outer peripheral surface of an inner ring 102. The outer diameter side cylindrical portion 123 of the slinger 120 wraps around the inner diameter side of the core metal cylindrical portion 111 of the seal ring 110, and the outer diameter side cylindrical portion 123 and the core metal cylindrical portion 111 overlap in the radial direction to form a labyrinth seal. In this type of combination seal ring 100, the core metal circular ring portion 112 extends perpendicularly from the core metal cylindrical portion 111 toward the inner diameter side, thereby narrowing the axial dimension of the seal and lengthening the distance between the ball rows for a given axial dimension of the bearing, thereby improving the bearing life. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2018-66448 A Summary of the Invention [Problem to be solved by the invention]

[0006] In the combined seal ring 100 described in Patent Document 1, the core metal cylindrical portion 111 of the seal ring 110 is fitted into the outer ring 101 and is compressed (reduced in diameter), and this deformation is also propagated to the core metal ring portion 112. Since the core metal ring portion 112 does not have anything to guide the deformation, such as the inner peripheral surface of the outer ring, deformation that reduces the diameter of the core metal ring portion 112 causes a buckling phenomenon due to resistance on the inner diameter side that prevents the diameter from being reduced, and the entire core metal ring portion 112 is deformed in a wavy manner as if it were wrinkled. The deformation is greater on the inner diameter side of the core metal ring portion 112, which has low rigidity.

[0007] In the side lip 130 vulcanization molded on the inner diameter side of this greatly deformed core metal ring portion 112, the lip base portion also undergoes wavy deformation, which may cause localized insufficient interference between the side lip 130 and the ring portion 122 of the slinger 120, resulting in a risk of reduced sealing performance. In addition, increasing the interference to ensure sufficient interference in consideration of this is not preferable, as it will cause an increase in the seal torque.

[0008] The above problem could be avoided if the portion of the core bar circular ring portion 112 near the outer diameter was curved at an acute angle, and the deformation that would cause the diameter to decrease was absorbed by the acute angle, thereby preventing the deformation from being transmitted to the core bar circular ring portion 112. However, it is difficult to curve the portion of the core bar circular ring portion 112 near the outer diameter at an acute angle because the axial dimension of the seal ring 110 would increase, and the distance between the ball rows would need to be shortened, which would shorten the distance between the points of application and reduce the bearing life.

[0009] The present invention has been made in consideration of the above-mentioned problems, and its object is to provide a combined seal ring that suppresses an increase in seal torque and has good sealing performance, and a long-life hub unit bearing that is equipped with such a combined seal ring. [Means for solving the problem]

[0010] Therefore, the above object of the present invention is achieved by the following configuration [1] relating to a combination seal ring. [1] A combination seal ring that is attached between an inner member and an outer member that are coaxially arranged to close an opening of an internal space that exists between an outer peripheral surface of the inner member and an inner peripheral surface of the outer member, a slinger having a cylindrical portion fixed to an outer circumferential surface of the inner member and a disk-shaped ring portion extending radially outward from one end of the cylindrical portion; a seal ring including a core having a cylindrical core portion fixed to an inner peripheral surface of the outer member and a disk-shaped core ring portion extending radially inward from the other end of the cylindrical core portion, and a seal portion having at least one seal lip arranged in sliding contact with or adjacent to the slinger; Equipped with the core metal ring portion has a low rigidity region that is continuously provided in a circumferential direction at a portion of the core metal ring portion close to an outer diameter thereof and has a rigidity lower than that of a surrounding area; Combination seal ring. The "portion closer to the outer diameter" refers to a portion on the outer diameter side of a radially intermediate portion between the inner diameter and the outer diameter of the core metal ring portion.

[0011] The above object of the present invention can be achieved by the following configuration [2] relating to a hub unit bearing. [2] An outer member having a double row outer ring raceway on an inner circumferential surface thereof; an inner member having a double row inner ring raceway on an outer circumferential surface thereof; A plurality of rolling elements are arranged to roll freely between the double row outer ring raceways and the double row inner ring raceways; and a combination seal ring according to [1] that closes at least one of the openings on both axial sides of an internal space that exists between the inner surface of the outer member and the outer surface of the inner member. Effect of the Invention

[0012] According to the combined seal ring and the hub unit bearing equipped with the combined seal ring of the present invention, it is possible to simultaneously achieve high sealing performance and low torque while preventing a decrease in lifespan. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a cross-sectional view of a hub unit bearing according to the present invention. [Diagram 2] FIG. 2 is an enlarged view of a portion surrounded by a dashed line X in FIG. 1, and is a cross-sectional view of the inboard side combination seal ring. [Diagram 3] FIG. 3 is a cross-sectional view of a first modified example of an inboard side combination seal ring. [Figure 4] FIG. 4 is a cross-sectional view of a second modified example of the inboard side combination seal ring. [Diagram 5] FIG. 5 is an enlarged view of a portion surrounded by a dashed line X' in FIG. 1, and is a cross-sectional view of the outboard side combination seal ring. [Figure 6] FIG. 6 is a cross-sectional view of a first modified example of the outboard side combination seal ring. [Figure 7] FIG. 7 is a cross-sectional view of a second modified example of the outboard side combination seal ring. [Figure 8] FIG. 8 is a cross-sectional view of a main portion of a conventional hub unit bearing. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a combined seal ring and a hub unit bearing including the combined seal ring according to the present invention will be described in detail with reference to the drawings.

[0015] As shown in FIG. 1, the hub unit bearing 10 of this embodiment is of the inner ring rotating type and is for a drive wheel, and comprises an outer ring 20 corresponding to the outer member, a hub 30 corresponding to the inner member, a plurality of rolling elements 15, an inboard side combined seal ring 50A (hereinafter also simply referred to as combined seal ring 50A) which is an inner sealing member, and an outboard side combined seal ring 50B (hereinafter also simply referred to as combined seal ring 50B) which is an outer sealing member.

[0016] With regard to the hub unit bearing 10, the axially outer side is the left side in FIG. 1 which is the outer side in the width direction of the vehicle when assembled to the vehicle, and is also referred to as the outboard side, and the axially inner side is the right side in FIG. 1 which is the central side in the width direction of the vehicle when assembled to the vehicle, and is also referred to as the inboard side.

[0017] The outer ring 20 is made of medium carbon steel such as S53C and has a generally cylindrical shape. The outer ring 20 has double row outer ring raceways 21a, 21b on its inner circumferential surface, and a stationary flange 22 protruding radially outward at the axially middle portion of its outer circumferential surface. The stationary flange 22 has support holes 23 penetrating in the axial direction at multiple locations in the circumferential direction. The outer ring 20 is supported and fixed to the suspension by bolts inserted through the support holes 23, and does not rotate even when the wheel rotates.

[0018] The hub 30 is disposed coaxially with the outer ring 20 on the radially inner side of the outer ring 20, and is formed by combining a hub ring 31 made of medium carbon steel such as S53C with an inner ring 33 made of high carbon chromium steel such as SUJ2. The hub 30 has double row inner ring raceways 32a, 32b on the outer circumferential surface in portions facing the double row outer ring raceways 21a, 21b.

[0019] The hub wheel 31 is a shaft member that fits around and holds the inner wheel 33, and has a shaft portion 34, a rotating flange 35, and a pilot portion 36. In this embodiment, since the hub unit bearing 10 is used for a drive wheel, the hub wheel 31 has a spline hole 37 that penetrates in the axial direction at the center.

[0020] A drive shaft is splined into spline hole 37. The drive shaft is rotated directly by a drive source such as an engine or an electric motor, or is rotated via a transmission. When the vehicle is traveling, the drive shaft rotates hub 30, which in turn rotates the wheels and braking rotors that are joined and fixed to rotation flange 35 of hub 30. However, when the present invention is applied to a hub unit bearing for a driven wheel, a solid hub wheel can be used.

[0021] The shaft portion 34 is provided in a range extending from the axially inner portion to the axially intermediate portion of the hub wheel 31. The shaft portion 34 has a small diameter portion 38 at its axially inner portion, the small diameter portion having an outer diameter smaller than a portion adjacent thereto on the axially outer side, on which the inner ring 33 is fitted, and has an outer row of inner ring raceways 32a at its outer peripheral surface at the axially intermediate portion. The shaft portion 34 further has a step surface 39 facing axially inward on its outer peripheral surface at the axially intermediate portion adjacent thereto on the axially outer side of the small diameter portion 38. The small diameter portion 38 has a crimping portion 40 at its axially inner end portion, which is bent radially outward and presses against the axially inner end face of the inner ring 33.

[0022] The rotating flange 35 is provided on a portion of the hub ring 31 that is located axially outward of the axially outer end of the outer ring 20, and has a generally circular ring shape. The rotating flange 35 has mounting holes 41 penetrating in the axial direction at multiple circumferential positions in a radially intermediate portion. A stud 11 is press-fitted into each of the mounting holes 41. A nut (not shown) is screwed into the tip of the stud 11. In this way, the wheel and braking rotor that constitute the wheel are fixed to the axially outer side of the rotating flange 35. When carrying out the present invention, a female threaded hole may be formed in the rotating flange, and a hub bolt may be directly screwed into the female threaded hole to fix the wheel and braking rotor to the axially outer side of the rotating flange.

[0023] The pilot portion 36 is provided at the axially outer end of the hub wheel 31 so that the wheel and the braking rotor are fitted thereto with a clearance fit without any rattle, and has a generally cylindrical shape.

[0024] The inner ring 33 has an annular shape and has an inner row of inner ring raceways 32b on its outer circumferential surface. The inner ring 33 is fitted onto a small diameter portion 38 of the shaft portion 34 by an interference fit, and is sandwiched from both axial sides by a stepped surface 39 and a crimped portion 40.

[0025] A plurality of rolling elements 15 are respectively disposed between double row outer ring raceways 21a, 21b and double row inner ring raceways 32a, 22b in a rollable manner while being held by cages 16a, 16b. As a result, the hub 30 is supported radially inside the outer ring 20 in a rotatable manner.

[0026] In this embodiment, balls are used as the rolling elements 15, but tapered rollers can also be used instead of balls. Also, in this embodiment, the pitch circle diameter of the rolling elements 15 in the axially inner row and the pitch circle diameter of the rolling elements 15 in the axially outer row are the same, but the present invention can also be applied to a different diameter PCD type hub unit bearing in which the pitch circle diameter of the rolling elements in the axially inner row and the pitch circle diameter of the rolling elements in the axially outer row are different from each other.

[0027] An annular internal space 42, which exists between the inner peripheral surface of the outer ring 20 and the outer peripheral surface of the hub 30 and in which the multiple rolling elements 15 are installed, is filled with grease (not shown). Any grease known in the art can be used. For example, mineral oil, fluorine oil, hydrocarbon oil, ester oil, or other synthetic oil can be used as the base oil, and metal soap such as lithium soap, urea, fluorine compound, bentonite, or the like can be used as the thickener. In addition, two or more types of base oil and thickener can be used in any combination. Furthermore, various additives (for example, antioxidants, rust inhibitors, extreme pressure agents, etc.) can be added as necessary.

[0028] In order to prevent the grease sealed in the internal space 42 from leaking into the external space and to prevent foreign matter such as muddy water from entering the internal space 42 from the external space, the opening on the axial inner side of the internal space 42 is sealed with a combination seal ring 50A, and the opening on the axial outer side of the internal space 42 is sealed with a combination seal ring 50B.

[0029] (Inboard side combination seal ring) Next, the inboard side combination seal ring 50A will be described in detail. As shown in FIG. 2, the combination seal ring 50A disposed at the axially inner opening of the internal space 42 includes a slinger 51A and a seal ring 61A.

[0030] The slinger 51A is made by pressing a metal plate such as a ferritic stainless steel plate such as SUS430, an austenitic stainless steel plate such as SUS304 when the encoder 55 described below is not fixed, or a cold-rolled steel plate (SPCC) that has been subjected to rust prevention treatment, and has a substantially U-shaped cross section and is annular as a whole. The slinger 51A is fitted and fixed to the outer circumferential surface (shoulder portion) of the inner ring 33.

[0031] The slinger 51A comprises a cylindrical portion 52 which is externally fixed to the inner ring 33 by an interference fit, a disk-shaped circular ring portion 53 which is bent at approximately a right angle from the axially inner end of the cylindrical portion 52 toward the radially outward side, and an outer diameter side cylindrical portion 54 which is bent from the radially outer end of the circular ring portion 53 toward the axially outward side, and is formed into an approximately U-shaped cross section.

[0032] An encoder 55 is fixed to the axially inner surface of the ring portion 53. The encoder 55 is made of a permanent magnet such as a rubber magnet or a plastic magnet, and the magnetization direction of the encoder 55 changes alternately and at equal intervals in the circumferential direction. A sensor (not shown) is disposed adjacent to the detection surface of the encoder 55, thereby making it possible to detect the rotation speed of the wheel. In this embodiment, the encoder 55 further has a slinger cover portion 55a that continues from the axially inner surface of the ring portion 53 and covers the outer peripheral surface of the outer diameter side cylindrical portion 54.

[0033] The seal ring 61A includes a core metal 62 and a seal portion 63.

[0034] The core bar 62 is made by pressing a cold-rolled steel plate or the like, has a substantially L-shaped cross section, and is generally annular. Specifically, a band-shaped plate material such as a cold-rolled steel plate is punched out to form a circular blank, and then a plurality of holes 66 (described later) are continuously formed in the blank in the circumferential direction, and then the blank is burred to form the substantially L-shaped cross section.

[0035] The core metal 62 includes a cylindrical core metal portion 64 that is fitted and fixed to the axially inner end of the outer ring 20, and a disk-shaped core metal ring portion 65 that is bent at a substantially right angle from the axially outer end of the core metal cylindrical portion 64 toward the radially inner side. The core metal ring portion 65 is bent in a crank shape so that its radially inner end is located axially more inward than the other portions.

[0036] A plurality of (for example, 30 to 90, preferably 50 to 70) holes 66 are formed continuously in the circumferential direction in a portion close to the outer diameter of the core metal ring portion 65. The annular belt-shaped portion where the plurality of holes 66 are formed continuously in the circumferential direction becomes a low-rigidity region 90 having lower rigidity than the surrounding portion of the core metal ring portion 65.

[0037] The seal portion 63 is made of rubber such as acrylonitrile butadiene rubber (NBR), acrylic rubber (ACM), or fluororubber (FKM), has an annular shape, and is fixed to the surface of the core metal 62 over its entire circumference. The seal portion 63 is vulcanization molded using a vulcanization mold, and has an annular cover portion 67 that covers the inner peripheral surface of the core metal cylindrical portion 64 over its entire circumference, two seal lips 68, 69 that extend from the radially inner ends of the core metal circular ring portion 65 and contact the surface of the slinger 51A or face each other via a gap, and a circular ring-shaped axial inner surface portion 70 that connects the annular cover portion 67 and the seal lips 68, 69 and extends radially along the axial inner surface of the core metal circular ring portion 65.

[0038] Furthermore, the seal portion 63 has a circular axial outer surface portion 71 formed by flowing molten rubber from multiple holes 66 formed in the core 62 to the back side (left side in FIG. 2) of the core ring portion 65 during vulcanization molding, and a gasket portion 80 is formed on the outer circumferential surface of the axial outer surface portion 71, protruding beyond the outer circumferential surface of the core cylindrical portion 64. This gasket portion 80 prevents muddy water and the like from entering the bearing through the fitting portion between the outer ring 20 and the core 62.

[0039] Of the two seal lips 68, 69, the seal lip 68 located closer to the external space extends in a radially outward direction as it moves axially inward, and the tip of the seal lip 68 contacts the axially outer surface of the circular ring portion 53 of the slinger 51A over its entire circumference.

[0040] On the other hand, the seal lip 69 disposed closer to the internal space extends radially inward as it extends axially outward. The tip of the seal lip 69 contacts the outer circumferential surface of the cylindrical portion 52 of the slinger 51A over the entire circumference.

[0041] The inner peripheral surface of the annular cover 67 and the outer peripheral surface of the encoder 55 overlap in the radial direction and face each other closely over the entire circumference, thereby forming a labyrinth seal 56 extending in the axial direction between the inner peripheral surface of the annular cover 67 and the outer peripheral surface of the encoder 55.

[0042] The core bar 62 has a cylindrical core bar portion 64 which is fitted into the inner peripheral surface of the outer ring 20 by an interference fit. For this reason, the compressive (diameter reduction) deformation of the core bar cylindrical portion 64 due to the press-fitting is transmitted to the core bar circular ring portion 65, causing the core bar circular ring portion 65 to buckle and causing the entire core bar circular ring portion 65 to deform in a wavy manner as if wrinkled.

[0043] However, the core metal circular ring portion 65 of the seal ring 61A in this embodiment has a low rigidity region 90 in which multiple (e.g., 30 to 90, preferably 50 to 70) holes 66 are formed continuously in the circumferential direction in the portion near the outer diameter, so that deformation of the core metal cylindrical portion 64 due to engagement with the outer ring 20 is absorbed by the low rigidity region 90, and propagation toward the inner diameter side from the low rigidity region 90 of the core metal circular ring portion 65 is suppressed.

[0044] As a result, the deformation of the inner diameter side of the core metal ring portion 65 is not wavy but is uniformly deformed (umbrella-shaped) around the entire circumference in one axial direction, and the amount of deformation itself is small. Since the amount of displacement of such deformation in one axial direction can be obtained in advance by FEM, experiments, etc., if the interference of the seal lips 68, 69 is set taking into account the amount of displacement of the core metal ring portion 65 in one axial direction, it is possible to prevent an increase in seal torque and a deterioration in muddy water durability.

[0045] Furthermore, by forming the gasket portion 80 by flowing molten rubber from the multiple holes 66 in the core 62 to the back side of the core ring portion 65 during vulcanization molding, the gasket portion (see Figs. 3 and 8) for covering the axially inner end portion 64a of the core cylindrical portion 64 is omitted. This eliminates the need for thinning processing to attach a gasket portion to the axially inner end portion 64a of the core cylindrical portion 64, thereby reducing manufacturing costs.

[0046] (First modified example of inboard side combination seal ring) As shown in Fig. 3, in the seal ring 61A of this modification, the core metal ring portion 65 does not have a plurality of holes 66 (see Fig. 2), and an annular thin-walled portion 72, which is a low-rigidity region 90 that is thinner than the surrounding area and protrudes toward the back surface side, is formed by press working in the portion near the outer diameter of the core metal ring portion 65. In this modification, the annular thin-walled portion 72 absorbs deformation of the core metal cylindrical portion 64 and suppresses the propagation of deformation from the annular thin-walled portion 72 of the core metal ring portion 65 toward the inner diameter side.

[0047] In this modified example, since there are no multiple holes 66, it is not possible to form the gasket portion 80 by flowing molten rubber from the multiple holes 66 in the core metal ring portion 65 to the back side of the core metal ring portion 65 as in the first embodiment. Therefore, it is necessary to perform a thinning process such as coining or turning on the end portion 64a on the axially inner side of the core metal cylindrical portion 64 to form the gasket portion 73 on the end portion 64a. However, this thinning process is simple, and therefore it is possible to suppress an increase in costs due to the process.

[0048] The annular thin-walled portion 72 that becomes the low-rigidity region 90 may be an annular thin-walled portion 72 that protrudes axially inward (toward the lip) of the core metal ring portion 65. Furthermore, the annular thin-walled portions 72 may be alternately protruding from both axial sides of the core metal ring portion 65, and a plurality of annular thin-walled portions 72 may be provided.

[0049] (Second modified example of inboard side combination seal ring) As shown in Figure 4, the seal ring 61A of this modified example has a core bar circular ring portion 65 (see Figure 2) of the first embodiment in which a plurality of holes 66 are formed continuously in the circumferential direction in a portion closer to the outer diameter of the core bar circular ring portion 65, and further has an uneven portion 74 in a portion closer to the inner diameter than the plurality of holes 66, in which a plurality of extrusion portions 74a extruded outward or inward in the axial direction and flat portions 74b are arranged alternately in the circumferential direction.

[0050] Since the axial rigidity of the radially extending uneven portions 74 is greater than the axial rigidity of the core metal ring portion 65 of the first embodiment that does not have the uneven portions 74, it is possible to significantly reduce deformation on the inner diameter side of the low rigidity region 90 of the core metal ring portion 65. As a result, the interference of the seal lip 69 becomes approximately constant in the circumferential direction, and sealing performance is improved without increasing the seal torque.

[0051] Note that this modified example is an example of combining multiple holes 66 (see Figure 2) in the core metal ring portion 65 with a high rigidity portion, i.e., an uneven portion 74, provided closer to the inner diameter than the multiple holes 66. However, it is also possible to combine the uneven portion 74 with a ring-shaped thin-walled portion 72 (see Figure 3), which is a low rigidity region 90 provided closer to the outer diameter of the core metal ring portion 65. Furthermore, instead of the uneven portion, a convex rib extending in the circumferential direction may be provided to form a portion with high rigidity.

[0052] (Outboard side combination seal ring) Next, the outboard side combination seal ring 50B will be described in detail with reference to FIG. The outboard side combined seal ring 50B includes a slinger 51B and a seal ring 61B, and is disposed in the opposite direction to the slinger 51A and seal ring 61A of the combined seal ring 50A to close the axially outer opening of the internal space 42 that exists between the outer ring 20 and the hub wheel 31. Below, the slinger 51B and the seal ring 61B will be described using the same reference numerals for configurations that are substantially the same as those of the slinger 51A and the seal ring 61A, and different configurations will be mainly described.

[0053] Like the combined seal ring 50A, the slinger 51B has a cylindrical portion 52, a disk-shaped ring portion 53, and an outer diameter side cylindrical portion 54, and is fitted to the axially inner root portion of the rotation flange 35 of the hub wheel 31. The axially outer side surface of the ring portion 53 is formed with a ring-shaped side portion 75 equipped with a gasket portion 75b for preventing water from entering the fitting surface between the cylindrical portion 52 and the hub wheel 31. The side portion 75 is provided with a protrusion 75a for guiding the inner end surface of the cylindrical portion 52 when multiple combined seal rings 50B are wrapped in a straight roll.

[0054] The core metal 62 of the seal ring 61B has an outer diameter side annular portion 76 formed by bending an axially outer end of a core metal cylindrical portion 64 at a substantially right angle toward the outer diameter side. The core metal 62 is formed such that the outer diameter side annular portion 76 abuts against the axially outer side surface 20a of the outer ring 20, while the core metal cylindrical portion 64 fits into the inner peripheral surface end of the outer ring 20.

[0055] The seal portion 63 has an annular gasket portion 77 that continues from the annular cover portion 67 that covers the inner circumferential surface of the core metal cylindrical portion 64, covers the axially outer surface and outer diameter side end face 76a of the outer diameter side annular portion 76, and extends outward. The seal portion 63 is also formed with a seal lip 78 that extends radially outward from the radial middle of the gasket portion 77 toward the axially outer side. The seal lip 78 overlaps with the axially inner surface of the rotating flange 35 when viewed radially, forming a labyrinth seal 56A between them.

[0056] Furthermore, since the outboard side combination seal ring 50B does not have an encoder 55, a labyrinth seal 56 is formed between the inner surface of the annular cover portion 67 and the outer surface of the outer diameter side cylindrical portion 54 of the slinger 51B.

[0057] The other structure and operation are substantially the same as those of the combination seal ring 50A. That is, the core metal circular ring portion 65 of the seal ring 61B has a low rigidity region 90 formed by a plurality of holes 66 in a portion close to the outer diameter, and therefore the deformation of the core metal cylindrical portion 64 caused by fitting with the outer ring 20 is absorbed by the low rigidity region 90. The propagation of the deformation from the low rigidity region 90 of the core metal circular ring portion 65 to the inner diameter side is suppressed, and the interference of the seal lips 68, 69 can be made uniform, and it becomes possible to prevent an increase in the seal torque and a deterioration in muddy water durability while preventing a decrease in the lifespan. In this example, since the outer diameter of the inner end face of the outer diameter side cylindrical portion 54 is smaller than the low rigidity region 90, the labyrinth gap formed by the inner end face of the outer diameter side cylindrical portion 54 and the circular ring-shaped axial outer surface portion 71 extending radially along the axial outer surface of the core metal circular ring portion 65 is also narrowed, thereby enhancing the labyrinth effect.

[0058] In addition, by flowing molten rubber from the multiple holes 66 in the core wire 62 to the back side of the core wire circular ring portion 65 during vulcanization molding to form the gasket portion 80, it is possible to omit the gasket portion for covering the axially inner end portion 64a of the core wire cylindrical portion 64, eliminating the need to thin the axially inner end portion 64a of the core wire cylindrical portion 64, and reducing manufacturing costs.

[0059] (First modified example of the outboard side combination seal ring) As shown in Figure 6, the combination seal ring 50B of this modified example does not have multiple holes 66 (see Figure 5) in the core metal ring portion 65, and instead forms a low rigidity region 90 by an annular thin-walled portion 72 that protrudes toward the front side near the outer diameter of the core metal ring portion 65.

[0060] Even in this modified example, in order to form the gasket portion 77 that covers the outer diameter side end face 76a of the outer diameter side annular portion 76, it is necessary to apply thinning processing such as coining or turning to the outer diameter side end face 76a. However, since this thinning processing is simple, it is possible to suppress an increase in processing costs.

[0061] (Second modified example of the outboard side combination seal ring) As shown in Fig. 7, the combined seal ring 50B of this modification has a core metal circular ring portion 65 of the outboard side combined seal ring 50B shown in Fig. 5, which has a plurality of holes 66, and has an uneven portion 74, in which a plurality of extrusion portions 74a and flat portions 74b are alternately arranged in the circumferential direction, provided in a portion closer to the inner diameter than the plurality of holes 66 to prevent deformation of the portion closer to the inner diameter than the plurality of holes 66. The uneven portion 74 can also be combined with an annular thin portion 72 provided on the outer diameter side portion of the core metal circular ring portion 65 shown in Fig. 6.

[0062] The present invention is not limited to the above-described embodiments and modifications, but can be modified and improved as appropriate. For example, the combined seal ring of the present invention is not limited to the third generation hub unit bearing as shown in FIG. 1, but can also be applied to hub unit bearings of other configurations.

[0063] As described above, the present specification discloses the following: (1) A combination seal ring that is attached between an inner member and an outer member that are coaxially arranged to close an opening of an internal space that exists between an outer peripheral surface of the inner member and an inner peripheral surface of the outer member, a slinger having a cylindrical portion fixed to an outer circumferential surface of the inner member and a disk-shaped ring portion extending radially outward from one end of the cylindrical portion; a seal ring including a core having a cylindrical core portion fixed to an inner peripheral surface of the outer member and a disk-shaped core ring portion extending radially inward from the other end of the cylindrical core portion, and a seal portion having at least one seal lip arranged in sliding contact with or adjacent to the slinger; Equipped with The core metal ring portion has a low rigidity region that is circumferentially continuous at a portion of the core metal ring portion close to the outer diameter thereof and has a low rigidity region that is lower in rigidity than the surrounding area. According to this configuration, an increase in the seal torque is suppressed and the sealing performance is improved.

[0064] (2) The combination seal ring according to (1), wherein the low rigidity region has a plurality of holes formed continuously in the circumferential direction of the core metal circular ring portion. According to this configuration, the low rigidity region can be formed easily and inexpensively.

[0065] (3) The combination seal ring according to (1), wherein the low rigidity region is an annular thin-walled portion that is continuously formed in the circumferential direction of the core metal circular ring portion and is thinner than the surrounding area. According to this configuration, the low rigidity region can be easily formed by the annular thin portion.

[0066] (4) A combination seal ring described in any one of (1) to (4), wherein the core metal circular ring portion has an annular uneven portion on the inner diameter side of the low rigidity region, in which a plurality of protrusions protruding to one or the other axial side are formed around the circumference. According to this configuration, by providing an annular uneven portion further on the inner diameter side than the low rigidity region, the rigidity of the portion on the inner diameter side than the low rigidity region can be increased, and deformation of the portion on the inner diameter side can be suppressed.

[0067] (5) an outer member having a double row outer ring raceway on an inner circumferential surface thereof; an inner member having a double row inner ring raceway on an outer circumferential surface thereof; A plurality of rolling elements are arranged to roll freely between the double row outer ring raceways and the double row inner ring raceways; A hub unit bearing comprising: a combined seal ring according to any one of (1) to (4) that closes at least one of openings on both axial sides of an internal space that exists between an inner peripheral surface of the outer member and an outer peripheral surface of the inner member. According to this configuration, a hub unit bearing can be obtained in which the axial opening of the internal space existing between the inner peripheral surface of the outer member and the outer peripheral surface of the inner member is sealed with a combination seal ring. [Explanation of symbols]

[0068] 10 Hub unit bearing 15 Rolling elements 20 Outer ring (outer member) 21a, 21b Outer raceway 30 Hub (inner part) 31 Hub ring (inner part) 32a, 32b Inner raceway 33 Inner ring (inner part) 42 Interior Space 50A Inboard combination seal ring (combination seal ring) 50B Outboard side combination seal ring (combination seal ring) 51A, 51B Slinger 52 Cylindrical part 53 Circular part 61A, 61B Seal ring 62 Core 63 Seal part 64 Core cylinder 65 Core metal ring part 66 holes 68, 69 Seal lip 72 Annular thin section 74 Uneven part 80 Gasket part 90 Low stiffness area

Claims

1. A combination seal ring that is attached between an inner member and an outer member that are coaxially arranged to close an opening of an internal space that exists between an outer peripheral surface of the inner member and an inner peripheral surface of the outer member, a slinger having a cylindrical portion fixed to an outer circumferential surface of the inner member and a disk-shaped ring portion extending radially outward from one end of the cylindrical portion; a seal ring including a core having a cylindrical core portion fixed to an inner peripheral surface of the outer member and a disk-shaped core ring portion extending radially inward from the other end of the cylindrical core portion, and a seal portion having at least one seal lip arranged in sliding contact with or adjacent to the slinger; Equipped with the core metal ring portion has a low rigidity region that is continuously provided in a circumferential direction at a portion of the core metal ring portion close to an outer diameter thereof and has a rigidity lower than that of a surrounding area; Combination seal ring.

2. The low rigidity region has a plurality of holes formed continuously in the circumferential direction of the core metal ring portion. The combination seal ring of claim 1 .

3. The low rigidity region is an annular thin-walled portion that is continuously formed in the circumferential direction of the core metal circular ring portion and is thinner than the surrounding area. The combination seal ring of claim 1 .

4. the core metal ring portion has an annular uneven portion on the inner diameter side of the low rigidity region, the annular uneven portion having a plurality of protrusions formed in a circumferential direction, the protrusions protruding to one axial side or the other axial side. The combination seal ring of claim 1 .

5. an outer member having a double row outer ring raceway on an inner circumferential surface; an inner member having a double row inner ring raceway on an outer circumferential surface thereof; A plurality of rolling elements are arranged to roll freely between the double row outer ring raceways and the double row inner ring raceways; 5. A hub unit bearing comprising: the combined seal ring according to claim 1, which closes at least one of openings on both axial sides of an internal space existing between an inner peripheral surface of the outer member and an outer peripheral surface of the inner member.

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