Combined seal ring and hub unit bearing

Abstract

To provide a combination seal ring capable of reducing rotational torque. [Solution] The seal ring (23) has a core (32) and a seal material (33) having only a side lip (37) as a sliding lip that extends in a direction approaching the external space as it approaches the tip of the core (32). The core (32) has a large-diameter cylindrical core (34) fitted into the outer ring (2), a small-diameter cylindrical core (35) disposed radially inside the large-diameter cylindrical core (34), and a core ring portion (36) connecting the axially outer end of the large-diameter cylindrical core (34) and the axially outer end of the small-diameter cylindrical core (35). The side lip (37) has a base end connected to a portion of the seal base (38) of the seal material (33) that covers the outer peripheral surface of the small-diameter cylindrical core (35), and a tip end that slides against the axially outer surface of the slinger ring portion (26).

Description

[Technical Field]

[0001] The present disclosure relates to a combination seal ring and a hub unit bearing. [Background technology]

[0002] Hub unit bearings, which are used to support the rotation of automobile wheels relative to the suspension system, are used in an environment where they are directly exposed to muddy water, so they require high-level sealing performance.On the other hand, hub unit bearings are required to keep rotational torque low in order to reduce automobile fuel consumption.

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

[0004] FIG. 8 shows a hub unit bearing 100 of a conventional structure described in Japanese Patent Application Laid-Open No. 2023-29119.

[0005] The hub unit bearing 100 has an outer ring 101 and a hub 102. An axially inner opening of an annular space 103 existing between the inner peripheral surface of the outer ring 101 and the outer peripheral surface of the hub 102 is closed by a combination seal ring 104, which is a sealing member.

[0006] The combination seal ring 104 includes a slinger 105 and a seal ring 106 .

[0007] Slinger 105 has a substantially horizontal U-shaped cross section and is fixed to hub 102. Slinger 105 includes a metal slinger body 107 and a slinger seal member 108 made of an elastic material that is joined and fixed to slinger body 107.

[0008] The slinger body 107 has a slinger small diameter cylindrical portion 109 fitted onto the hub 102, a slinger large diameter cylindrical portion 110 arranged radially outside the slinger small diameter cylindrical portion 109, and a slinger circular ring portion 111 connecting the axially inner end of the slinger small diameter cylindrical portion 109 and the axially inner end of the slinger large diameter cylindrical portion 110.

[0009] The seal ring 106 is fixed to the outer ring 101. The seal ring 106 has a core metal 112 and a seal material 113 coupled to the core metal 112.

[0010] The core metal 112 is composed of a large diameter cylindrical core metal portion 114 fitted inside the outer ring 101 and a circular core metal portion 115 bent radially inward from the axially outer end of the large diameter cylindrical core metal portion 114.

[0011] The seal material 113 has a seal base 116 that covers the surface of the core metal 112. The seal material 113 has, as sliding lips that slide against the slinger 105, two side lips 117a, 117b, each with its tip end in sliding contact with the axial outer surface of the slinger circular ring portion 111, and one grease lip 118, with its tip end in sliding contact with the outer peripheral surface of the slinger small-diameter cylindrical portion 109.

[0012] In the hub unit bearing 100, the combined seal ring 104 is provided with only side lips 117a, 117b as sliding lips that extend in a direction approaching the external space 120 as they approach their tip, i.e., so-called mud lips, and is not provided with a dust lip (axial lip, radial lip). Dust lips tend to increase seal torque because they generate tension force due to circumferential tensile stress, whereas side lips generate tension force due to bending stress, thereby keeping seal torque low. Therefore, the seal torque of the combined seal ring 104 can be kept low, and the torque of the hub unit bearing 100 can be reduced.

[0013] Additionally, the combination seal ring 104 is provided with a labyrinth seal 119 between the portion of the seal base 116 that covers the inner peripheral surface of the large-diameter cylindrical core portion 114 and the portion of the slinger seal material 108 that covers the outer peripheral surface of the large-diameter cylindrical slinger portion 110. This prevents muddy water from adhering to the side lips 117a, 117b, improving the durability of the side lips 117a, 117b. [Prior art documents] [Patent documents]

[0014] [Patent Document 1] Japanese Patent Application Publication No. 2023-29119 Summary of the Invention [Problem to be solved by the invention]

[0015] The combined seal ring 104 of the conventional structure described in JP 2023-29119 A has only side lips 117a, 117b as sliding lips (mud lips) for preventing muddy water from entering the annular space 103 from the external space 120. For this reason, in order to ensure the sealing performance of the combined seal ring 104 while also achieving low torque, it is important to provide the minimum necessary interference to the side lips 117a, 117b.

[0016] However, with the combined seal ring 104 having the conventional structure, it is difficult to provide the minimum necessary interference between the side lips 117a and 117b.

[0017] That is, the base ends of the side lips 117a, 117b are connected to a portion of the seal base 116 constituting the seal ring 106 that covers the radially inner portion of the axially inner surface of the core ring portion 115. The core large-diameter cylindrical portion 114 constituting the core 112 reduces in diameter when fitted into the outer ring 101, but the radially inner portion of the core ring portion 115 does not reduce in diameter and instead deforms in an axially undulating manner (left-right direction in FIG. 8 ) along the circumferential direction. Therefore, the axial position of the radially inner portion of the core ring portion 115 is not constant throughout the circumferential direction but varies depending on the circumferential position. Therefore, in the combined seal ring 104 having a conventional structure, the interference of the side lips 117a, 117b must be set large so that the interference of the side lips 117a, 117b is not insufficient even at the axially outermost portion of the radially inner portion of the core ring portion 115, which results in an increase in seal torque.

[0018] An object of the present disclosure is to provide a combination seal ring that can reduce seal torque. [Means for solving the problem]

[0019] A combination seal ring according to one embodiment of the present disclosure is attached between an inner member and an outer member that are arranged coaxially with each other, and seals an opening on one axial side of an annular space that exists between the outer peripheral surface of the inner member and the inner peripheral surface of the outer member, and comprises a slinger fixed to the inner member and a seal ring fixed to the outer member.

[0020] The slinger has a slinger small diameter cylindrical portion that is fitted onto the inner member, a slinger large diameter cylindrical portion that is arranged radially outside the slinger small diameter cylindrical portion, and a slinger ring portion that connects one axial end of the slinger small diameter cylindrical portion to one axial end of the slinger large diameter cylindrical portion.

[0021] The seal ring has a core metal and a seal material having only a side lip as a sliding lip that extends in a direction approaching the external space as it approaches the tip side of the core metal.

[0022] The core wire has a large diameter cylindrical portion that is fitted into the outer member, a small diameter cylindrical portion that is arranged radially inside the large diameter cylindrical portion, and a core wire ring portion that connects the other axial end of the large diameter cylindrical portion and the other axial end of the small diameter cylindrical portion.

[0023] In addition to the side lip, the sealing material has a seal base covering the surface of the core metal, and a grease lip that extends in a direction approaching the annular space as it approaches the tip, and whose tip is in close contact with or sliding contact with the outer peripheral surface of the inner member or the slinger small diameter cylindrical portion.

[0024] In one embodiment of the combination seal ring of the present disclosure, the side lip has its base end connected to the portion of the seal base that covers the outer peripheral surface of the core small diameter cylindrical portion, and its tip end can be made to slide against the side surface on the other axial side of the slinger circular ring portion.

[0025] In the combination seal ring according to one aspect of the present disclosure, the seal ring may include a reinforcing core metal fitted inside the large-diameter cylindrical core metal portion. In this case, the reinforcing core metal may have a substantially horizontal U-shaped or substantially horizontal J-shaped cross section.

[0026] In one aspect of the combined seal ring of the present disclosure, the seal ring may have an annular groove located radially inward of one axial end of the large-diameter cylindrical core portion, the annular groove being open only to one axial side and the radially inward direction. The slinger may include a metal slinger body having the small-diameter cylindrical slinger portion, the large-diameter cylindrical slinger portion, and the slinger ring portion, and a slinger seal member made of an elastic material bonded and fixed to the slinger body, and the slinger seal member may have an annular protrusion extending inside the annular groove.

[0027] A hub unit bearing according to one embodiment of the present disclosure comprises an outer member having a double-row outer ring raceway on its inner peripheral surface, an inner member having a double-row inner ring raceway on its outer peripheral surface, a plurality of rolling elements arranged to roll freely between the double-row outer ring raceway and the double-row inner ring raceway, and a combination seal ring that closes an opening on one axial side of an annular space existing between the inner peripheral surface of the outer member and the outer peripheral surface of the inner member, wherein the combination seal ring is a combination seal ring according to one embodiment of the present disclosure. [Effects of the Invention]

[0028] According to the combination seal ring of one aspect of the present disclosure, the seal torque can be reduced. [Brief explanation of the drawings]

[0029] [Figure 1] FIG. 1 is a half cross-sectional view showing a hub unit bearing according to a first example of an embodiment of the present disclosure. [Figure 2] FIG. 2 is an enlarged view of the X portion of FIG. [Figure 3] FIG. 3 is a diagram corresponding to FIG. 2 and illustrating a second example of an embodiment of the present disclosure. [Figure 4] FIG. 4 is a diagram corresponding to FIG. 2 and illustrating a third example of an embodiment of the present disclosure. [Figure 5] FIG. 5 is a diagram corresponding to FIG. 2 and illustrating a fourth example of an embodiment of the present disclosure. [Figure 6] FIG. 6 is a diagram corresponding to FIG. 2 and relating to a fifth example of an embodiment of the present disclosure. [Figure 7] FIG. 7 is a diagram corresponding to FIG. 2 and relating to a sixth example of the embodiment of the present disclosure. [Figure 8] FIG. 8 is an enlarged partial cross-sectional view of a hub unit bearing having a conventional structure. DETAILED DESCRIPTION OF THE INVENTION

[0030] [Example 1] A first example of an embodiment of the present disclosure will be described with reference to FIGS.

[0031] In this example, a case where a composite seal ring according to an embodiment of the present disclosure is incorporated into a hub unit bearing will be described. However, the composite seal ring according to an embodiment of the present disclosure can be incorporated into bearings and rotating machines having other structures and can be used without being limited to hub unit bearings.

[0032] [Overall structure of hub unit bearing] Hub unit bearing 1 comprises an outer ring 2, a hub 3, a plurality of rolling elements 4a, 4b, and a combined seal ring 5. Hub unit bearing 1 of this example has an inner ring rotating structure. In this example, outer ring 2 corresponds to the outer member recited in the claims, and hub 3 corresponds to the inner member recited in the claims.

[0033] The hub unit bearing 1 of this example is a so-called third-generation hub unit bearing for a driving wheel. However, the hub unit bearing of one embodiment of the present disclosure can also be applied to hub unit bearings for driven wheels, first-generation, second-generation, and so-called 2.5th-generation hub unit bearings that combine an inner-ring rotating second-generation hub unit bearing with a hub spindle, etc.

[0034] In the following description, unless otherwise specified, the axial direction, radial direction, and circumferential direction of the hub unit bearing 1 refer to the axial direction, radial direction, and circumferential direction of the outer ring 2. The axial direction, radial direction, and circumferential direction of the outer ring 2 coincide with the axial direction, radial direction, and circumferential direction of the hub 3. Additionally, the outer axial direction refers to the outer side in the width direction of the vehicle when the hub unit bearing 1 is assembled to the vehicle, and the inner axial direction refers to the center side in the width direction of the vehicle when the hub unit bearing 1 is assembled to the vehicle.

[0035] The outer ring 2 has a hollow shape and is made of a hard metal such as medium carbon steel, etc. The outer ring 2 has double-row outer ring raceways 6a, 6b on its inner circumferential surface.

[0036] Each of the outer ring raceways 6a, 6b has a generatrix shape that corresponds to the shapes of the multiple rolling elements 4a, 4b. When the multiple rolling elements 4a, 4b are balls, each of the outer ring raceways 6a, 6b has an arc-shaped generatrix shape, and when the multiple rolling elements 4a, 4b are tapered rollers, each of the outer ring raceways 6a, 6b has a linear generatrix shape that is inclined with respect to the central axis of the outer ring 2. In this example, because the multiple rolling elements 4a, 4b are balls, each of the outer ring raceways 6a, 6b has an arc-shaped generatrix shape.

[0037] In this example, the outer ring 2 has a stationary flange 7 that protrudes radially outward in an axially intermediate portion. The stationary flange 7 has flange-side support holes 8 that penetrate in the axial direction at multiple locations circumferentially in the radially intermediate portion. The outer ring 2 is supported and fixed to the knuckle by inserting support bolts (not shown) into one of the flange-side support holes 8 and a knuckle-side support hole provided in the knuckle of the suspension device and screwing them into the other support hole.

[0038] The hub 3 is disposed radially inside the outer ring 2 and coaxially with the outer ring 2. The hub 3 has double-row inner ring raceways 9a, 9b on its outer circumferential surface.

[0039] Each of the inner ring raceways 9a, 9b has a generatrix shape that corresponds to the shapes of the multiple rolling elements 4a, 4b. When the multiple rolling elements 4a, 4b are balls, each of the inner ring raceways 9a, 9b has an arc-shaped generatrix shape, and when the multiple rolling elements 4a, 4b are tapered rollers, each of the inner ring raceways 9a, 9b has a linear generatrix shape that is inclined with respect to the central axis of the outer ring 2. In this example, because the multiple rolling elements 4a, 4b are balls, each of the inner ring raceways 9a, 9b has an arc-shaped generatrix shape.

[0040] In this example, the hub 3 has a rotating flange 10 that protrudes radially outward at a portion that protrudes axially outward beyond the outer ring 2, and has a cylindrical pilot portion 11 at the axially outer end.

[0041] The rotating flange 10 has mounting holes 12 penetrating in the axial direction at a plurality of circumferential positions in a radially intermediate portion. Each of the mounting holes 12 is configured as a press-fit hole or a screw hole.

[0042] When each mounting hole 12 is configured as a press-fit hole, a stud 13 is press-fitted from the axially inner side into each mounting hole 12. A braking rotating body such as a brake disc and a wheel of a vehicle wheel are coupled and fixed to the rotating flange 10 by inserting the pilot portion 11 into a central hole provided in the center of each and inserting studs 13 into through-holes provided at multiple locations in the circumferential direction in the radially middle portion of each, and screwing a hub nut (not shown) onto the tip of the stud 13.

[0043] When each of the mounting holes 12 is configured as a threaded hole, the braking rotating body such as a brake disc and the wheel of the vehicle are connected and fixed to the rotating flange 10 by inserting the pilot portion 11 into the central hole provided in the center of each and threading hub bolts, which have been inserted into through holes provided at multiple locations circumferentially in the radially middle portion of each, into the mounting holes 12 from the outside in the axial direction.

[0044] In this example, each of the mounting holes 12 is configured as a press-fit hole, and a stud 13 is press-fitted into each of the mounting holes 12 .

[0045] Because the hub unit bearing 1 of this example is a hub unit bearing for a drive wheel, the hub 3 has a spline hole 14 that passes through the hub 3 in the axial direction at its radial center. The tip of a drive shaft that is driven to rotate by an engine or electric motor as a drive source is spline-engaged with the spline hole 14. When the vehicle is running, the hub 3 is driven to rotate by the drive shaft, and the wheel and braking rotor that are coupled and fixed to the rotating flange 10 of the hub 3 are driven to rotate.

[0046] When the hub unit bearing according to one aspect of the present disclosure is applied to a hub unit bearing for a driven wheel, the hub can be configured to be solid.

[0047] The hub 3 includes an inner ring 15 and a hub ring 16 .

[0048] The inner ring 15 is made of a hard metal such as bearing steel and has a cylindrical shape.

[0049] The inner ring 15 has, at the axially inner middle portion of the outer circumferential surface, the inner ring raceway 9b, which is one of the multiple rows of inner ring raceways 9a, 9b.

[0050] The hub ring 16 has, at the axially intermediate portion of the outer peripheral surface, the inner ring raceway 9a on the outer side in the axial direction out of a plurality of rows of inner ring raceways 9a, 9b.

[0051] The hub ring 16 has a rotation flange 10 at a portion located axially outward of the inner ring raceway 9a on the axially outer side, and also has a pilot portion 11 at the axially outer end.

[0052] Furthermore, the hub ring 16 has a fitting shaft portion 17 at a portion axially more inward than the axially outer inner ring raceway 9a, the fitting shaft portion having an outer diameter smaller than the outer diameter of the portion adjacent to it on the axially outer side. The hub ring 16 has a stepped surface 18 that connects the portion of its outer peripheral surface adjacent to it on the axially inner side of the axially outer inner ring raceway 9a with the outer peripheral surface of the fitting shaft portion 17, and faces axially inward.

[0053] The inner ring 15 is fixedly connected to the hub ring 16 by abutting its outer axial end face against a stepped surface 18 of the hub ring 16 and by being externally fitted onto the mating shaft portion 17 of the hub ring 16 with an interference fit.

[0054] The hub wheel and inner ring can also be joined and fixed by clamping the inner ring from both axial sides between the stepped surface of the hub wheel and a crimping portion provided on the axially inner end of the hub wheel, or by clamping the inner ring from both axial sides between the stepped surface of the hub wheel and a nut threaded onto the axially inner end of the hub wheel.

[0055] Because the hub unit bearing 1 of this example is a so-called third-generation hub unit bearing, the hub ring 16 is made entirely of a hard metal such as medium carbon steel. However, for example, when a hub unit bearing according to one embodiment of the present disclosure is applied to a so-called second-and-a-half-generation hub unit bearing, the hub ring can also be formed by combining a hub spindle having a rotation flange and a pilot portion with a separate inner ring having an inner ring raceway on the axially outer side of its outer peripheral surface.

[0056] The rolling elements 4a, 4b are arranged to roll freely between multiple rows of outer ring raceways 6a, 6b and multiple rows of inner ring raceways 9a, 9b, with multiple rolling elements in each row. In this example, the rolling elements 4a, 4b are arranged to roll freely at equal intervals in the circumferential direction between the double rows of outer ring raceways 6a, 6b and the double rows of inner ring raceways 9a, 9b, with multiple rolling elements in each row held by cages 19a, 19b. A back-to-back type (DB type) contact angle is imparted to the rolling elements 4a, 4b arranged in the double rows.

[0057] The rolling elements 4a and 4b are made of hard metal such as bearing steel or ceramics.

[0058] The rolling elements 4a and 4b are made up of balls or tapered rollers. In this example, the rolling elements 4a and 4b are made up of balls.

[0059] The hub unit bearing 1 of this example has a so-called equal diameter PCD type structure in which the pitch circle diameter of the axially outer rolling element 4a is equal to the pitch circle diameter of the axially inner rolling element 4b. However, the hub unit bearing of one embodiment of the present disclosure can also be applied to a so-called different diameter PCD type hub unit bearing in which the pitch circle diameter of the axially outer rolling element is larger or smaller than the pitch circle diameter of the axially inner rolling element.

[0060] In the hub unit bearing 1 of this example, the combined seal ring 5 closes the axially inner opening of the annular space 20, which is an internal space that exists between the inner peripheral surface of the outer ring 2 and the outer peripheral surface of the hub 3. For this reason, in the following description of the combined seal ring 5, the axially inner side corresponds to one axial side in the claims, and the axially outer side corresponds to the other axial side in the claims.

[0061] However, when implementing a hub unit bearing according to one aspect of the present disclosure, the combined seal ring may close the axially outer opening of the annular space in addition to or instead of the axially inner opening of the annular space. In this case, with respect to the combined seal ring closing the axially outer opening of the annular space, the axially outer side corresponds to one axial side in the claims, and the axially inner side corresponds to the other axial side in the claims.

[0062] The hub unit bearing 1 of this example further has a sealing device 21 that closes the opening on the axially outer side of the annular space 20. The sealing device 21 is not limited to this, but can be configured, for example, as a seal ring having a core metal fitted and fixed to the end portion on the axially outer side of the outer ring 2, at least one seal lip whose tip end is in sliding contact with the surface of the hub or a slinger fitted and fixed to the outside of the hub, and a sealing material bonded and fixed to the core metal by vulcanization adhesion.

[0063] The combined seal ring 5 and the seal device 21 prevent leakage of grease (not shown) sealed in the annular space 20 and also prevent foreign matter such as muddy water from entering the annular space 20 .

[0064] [Structure of combined seal ring] The combination seal ring 5 comprises a slinger 22 and a seal ring 23. The slinger 22 is fixed to the hub 3, which corresponds to the inner member, and rotates during use. In contrast, the seal ring 23 is fixed to the outer ring 2, which corresponds to the outer member, and does not rotate during use.

[0065] Slinger

[0066] The slinger 22 has a slinger small diameter cylindrical portion 24 fitted onto the outside of the hub 3, a slinger large diameter cylindrical portion 25 arranged radially outside the slinger small diameter cylindrical portion 24, and a slinger circular ring portion 26 connecting the axially inner end of the slinger small diameter cylindrical portion 24 and the axially inner end of the slinger large diameter cylindrical portion 25.

[0067] In this example, the slinger 22 is composed of a metal slinger body 27 and a slinger seal member 28 made of an elastic material that is bonded and fixed to the slinger body 27. The slinger 22 is constructed by bonding and fixing the slinger seal member 28 to the slinger body 27 by vulcanization adhesion. However, when implementing a combined seal ring according to one embodiment of the present disclosure, the slinger may also be composed of only the slinger body.

[0068] Slinger body 27 is formed into an annular shape by bending a metal plate such as a stainless steel plate or a rust-proofed cold-rolled steel plate. Slinger body 27 includes a small-diameter cylindrical slinger portion 24, a large-diameter cylindrical slinger portion 25, and a circular ring portion 26. In this example, slinger body 27 has a substantially horizontal U-shaped or substantially horizontal J-shaped cross section.

[0069] The slinger small diameter cylindrical portion 24 has a cylindrical shape and is fitted onto the outside of the hub 3. In this example, the slinger small diameter cylindrical portion 24 is fitted onto the axially inner end of the inner ring 15 that constitutes the hub 3 by an interference fit.

[0070] The slinger large-diameter cylindrical portion 25 has a cylindrical shape and is disposed substantially coaxially with the slinger small-diameter cylindrical portion 24. The slinger large-diameter cylindrical portion 25 has a shorter axial dimension than the slinger small-diameter cylindrical portion 24.

[0071] In this example, the axially inner surface of the slinger ring portion 26 is configured as a flat surface that is approximately perpendicular to the central axis of the slinger body 27, except for the ends on both radial sides.

[0072] The slinger seal member 28 is made of an elastic material such as an elastomer like rubber, and includes an outer diameter side covering portion 29 and a circular ring covering portion 30 .

[0073] The outer diameter side covering portion 29 covers the outer peripheral surface of the slinger large diameter cylindrical portion 25. In this example, the outer diameter side covering portion 29 covers the outer peripheral surface of the slinger large diameter cylindrical portion 25 over the entire axial length and the entire circumference, and also covers the entire axial outer end face of the slinger large diameter cylindrical portion 25. The outer diameter side covering portion 29 has a cylindrical outer peripheral surface except for the axial outer end portion.

[0074] The circular ring cover portion 30 covers the axial inner surface of the slinger circular ring portion 26. In this example, the circular ring cover portion 30 covers the axial inner surface of the slinger circular ring portion 26 over the entire radial length and circumference. The circular ring cover portion 30 has a cylindrical outer peripheral surface except for the axially inner end portion. The circular ring cover portion 30 has the same outer diameter as the outer diameter side cover portion 29.

[0075] In this example, the circular cover portion 30 has a detection surface 31 on its axially inner surface, where north and south poles are alternately and equally spaced in the circumferential direction. In other words, the circular cover portion 30 functions as an encoder. For this reason, in this example, the slinger seal material 28 is made of rubber (magnetic rubber) mixed with magnetic powder. The detection surface 31 is made of a flat surface that is approximately perpendicular to the central axis of the slinger 22.

[0076] The slinger seal material 28 may also include, as an optional component, a gasket portion that protrudes radially inward from the radially inner end of the annular cover portion 30 and whose tip elastically abuts against the outer peripheral surface of the hub 3.

[0077] <Seal ring> The seal ring 23 has a core metal 32 and a sliding lip that extends in a direction approaching the external space 56 as it approaches the tip end, i.e., a sealing material 33 that has only a side lip 37 as a so-called mud lip. In other words, the sealing material 33 does not have a dust lip (axial lip, radial lip) that causes its tip end to slide against the outer circumferential surface of the slinger small diameter cylindrical portion 24.

[0078] The core metal 32 has a large-diameter cylindrical core metal portion 34 fitted into the outer ring 2, a small-diameter cylindrical core metal portion 35 arranged radially inside the large-diameter cylindrical core metal portion 34, and a circular core metal portion 36 connecting the axially outer end of the large-diameter cylindrical core metal portion 34 and the axially outer end of the small-diameter cylindrical core metal portion 35. In this example, the core metal 32 has a substantially horizontal U-shaped or substantially horizontal J-shaped cross section.

[0079] The core metal 32 is formed into an annular shape by bending a metal plate such as a cold-rolled steel plate.

[0080] The large-diameter cylindrical core portion 34 has a cylindrical shape and is tightly fitted and fixed to the axially inner end of the outer ring 2. The large-diameter cylindrical core portion 34 is disposed radially outward of the outer diameter side cover portion 29 that covers the outer peripheral surface of the large-diameter cylindrical slinger portion 25.

[0081] The core small diameter cylindrical portion 35 has a cylindrical shape and is arranged approximately coaxially with the core large diameter cylindrical portion 34. The core small diameter cylindrical portion 35 is arranged radially outside the slinger small diameter cylindrical portion 24. The core small diameter cylindrical portion 35 has an axial dimension that is shorter than that of the core large diameter cylindrical portion 34. In this example, the axially inner end face of the core small diameter cylindrical portion 35 is located slightly axially inner than the axially outer end face of the slinger large diameter cylindrical portion 25.

[0082] The core metal ring portion 36 is disposed axially opposite the slinger ring portion 26. In this example, the core metal ring portion 36 has a generally crank-shaped cross section in which the radially inner portion is offset axially inward from the radially outer portion. The axially outer surface of the radially inner portion of the core metal ring portion 36 is disposed axially inward from the axially outer end of the slinger small-diameter cylindrical portion 24.

[0083] The seal member 33 is made of an elastic material such as an elastomer like rubber, and is bonded and fixed to the core metal 32 by vulcanization adhesion or the like.

[0084] In addition to the side lip 37, the sealing material 33 has a seal base 38 that covers the surface of the core wire 32, and a grease lip 39 that extends in a direction approaching the annular space 20 as it approaches the tip, and whose tip is in close opposition or sliding contact (light contact) with the outer peripheral surface of the hub 3 or the slinger small diameter cylindrical portion 24.

[0085] The seal base 38 is bonded and fixed to the surface of the core metal 32. In this example, the seal base 38 is bonded and fixed to the core metal 32 so as to cover the range of the core metal 32 from the axially inner end of the outer peripheral surface of the core metal large-diameter cylindrical portion 34 to the radially intermediate portion of the axially outer surface of the core metal ring portion 36. In other words, the seal base 38 covers the axially inner end, axially inner end face, and inner peripheral surface of the outer peripheral surface of the core metal large-diameter cylindrical portion 34, the axially inner side surface and the range from the radially inner end to the radially intermediate portion of the axially outer surface of the core metal ring portion 36, and the outer peripheral surface, axially inner end face, and inner peripheral surface of the core metal small-diameter cylindrical portion 35. The axially inner side surface of the portion of the seal base 38 covering the axially inner end face of the core metal large-diameter cylindrical portion 34 and the axially inner side surface (detected surface 31) of the ring cover portion 30 of the slinger 22 are located at approximately the same axial position.

[0086] In this example, the portion of the seal base 38 that covers the inner peripheral surface of the large-diameter cylindrical core portion 34 is configured to have a substantially cylindrical surface and is positioned closely opposite the outer peripheral surface of the outer diameter side cover portion 29 of the slinger 22, thereby forming an axial labyrinth seal 40 between them. This prevents foreign matter from the external space 56 from entering the portion between the slinger 22 and the seal ring 23 and adhering to the side lip 37.

[0087] Furthermore, in this example, the portion of seal base 38 that covers the inner peripheral surface of core small-diameter cylindrical portion 35 is configured as a substantially cylindrical surface and is positioned closely opposite the outer peripheral surface of slinger small-diameter cylindrical portion 24 of slinger 22, thereby forming an axial labyrinth seal 41 between them. This prevents foreign matter that passes through the sliding contact portion between the tip of side lip 37 and the axial outer surface of slinger ring portion 26 from reaching grease lip 39, and also prevents grease sealed in annular space 20 from reaching the sliding contact portion between the tip of side lip 37 and the axial outer surface of slinger ring portion 26.

[0088] In this example, the base end of the side lip 37 is connected to the axially inner end of the portion of the seal base 38 that covers the outer peripheral surface of the core small-diameter cylindrical portion 35, and the tip end is in sliding contact with the radially intermediate portion of the axially outer surface of the slinger ring portion 26. In this example, the side lip 37 has a conical cylindrical shape, and extends radially outward as it moves axially inward.

[0089] In this example, the seal 33 has only one side lip 37. However, in a hub unit bearing according to one aspect of the present disclosure, the seal may have multiple side lips.

[0090] The base end of the grease lip 39 is connected to the radially inner end of the portion of the seal base 38 that covers the axially outer surface of the core ring portion 36, and the tip end is in light contact with the axially outer end of the outer peripheral surface of the slinger small-diameter cylindrical portion 24. In this example, the grease lip 39 has a conical cylindrical shape and extends radially inward as it extends axially outward.

[0091] When implementing a hub unit bearing according to one aspect of the present disclosure, the tip of the grease lip can be positioned closely facing the outer peripheral surface of the slinger small diameter cylindrical portion, or the tip of the grease lip can be in sliding contact with or closely facing the outer peripheral surface of the hub.

[0092] According to the combination seal ring 5 of this embodiment, the seal torque can be reduced.

[0093] That is, the seal material 33 of the seal ring 23 constituting the combined seal ring 5 has only the side lip 37 as a sliding lip that extends in a direction approaching the external space 56 as it approaches the tip side, and does not have a dust lip (axial lip, radial lip). Therefore, with the combined seal ring 5 of this example, it is possible to keep the seal torque low compared to a structure having a dust lip on which tensile stress acts in the circumferential direction.

[0094] Furthermore, the core metal 32 of the seal ring 23 constituting the combination seal ring 5 has a small-diameter cylindrical core metal portion 35, which reinforces the radially inner end of the core metal ring portion 36. This increases the axial rigidity of the radially inner end of the core metal ring portion 36. Therefore, when the large-diameter cylindrical core metal portion 34 is fitted into the outer ring 2, the core metal ring portion 36 does not deform in an axially wavy manner along the circumferential direction, but rather deforms uniformly in the axial direction around the entire circumference. Specifically, when the intersection angle with the large-diameter cylindrical core portion 34 becomes an obtuse angle due to the effect of spring back, the core ring portion 36 deforms uniformly over the entire circumference, starting from the radially outer end and leaning axially inward in a direction that increases the intersection angle, whereas when the intersection angle with the large-diameter cylindrical core portion 34 becomes an acute angle due to the effect of spring back, the core ring portion 36 deforms uniformly over the entire circumference, starting from the radially outer end and leaning axially inward in a direction that decreases the intersection angle. As a result, the axial position of the radially inner end of the core ring portion 36 remains constant over the circumference.

[0095] For this reason, the interference of the side lip 37 does not need to be set large, as with the side lips 117a, 117b of the combined seal ring 100 with the conventional structure described in JP 2023-29119 A, as long as the intersection angle between the core ring portion 36 and the core large-diameter cylindrical portion 34 is adjusted to be obtuse or acute before the core 32 is fitted into the outer ring 2. Therefore, compared to the side lips 117a, 117b of the combined seal ring 100 with the conventional structure, the interference of the side lip 37 can be made smaller, and the seal torque of the side lip 37 can be kept low. As a result, the seal torque of the combined seal ring 5 can be kept low, and the torque of the hub unit bearing 1 can be reduced.

[0096] Furthermore, when the large-diameter cylindrical core portion 34 of the core 32 is fitted into the outer ring 2, the circular core portion 36 can be deformed uniformly in the axial direction over the entire circumference, thereby stabilizing the sliding contact between the tip of the grease lip 39 and the outer peripheral surface of the small-diameter cylindrical slinger portion 24. This effectively prevents grease leakage.

[0097] The combined seal ring 5 of this example is provided with an axial labyrinth seal 40 between the portion of the seal base 38 that covers the inner peripheral surface of the large-diameter cylindrical core portion 34 and the outer peripheral surface of the outer diameter side cover portion 29 of the slinger 22, so that the combined seal ring 5 can sufficiently ensure sealing performance even though it has a structure that only includes a side lip 37 as a so-called muddy water lip. Also, adhesion of foreign matter such as muddy water to the side lip 37 can be suppressed, thereby improving the durability of the side lip 37.

[0098] Furthermore, the combined seal ring 5 of this example is provided with an axial labyrinth seal 41 between the part of the seal base 38 that covers the inner surface of the core small diameter cylindrical portion 35 and the outer surface of the slinger small diameter cylindrical portion 24 of the slinger 22, thereby effectively preventing grease from leaking into the external space 56.

[0099] [Example 2] A second example of the embodiment of the present disclosure will be described with reference to FIG.

[0100] In this example, outer diameter side covering portion 29a of slinger 22a constituting combined seal ring 5a covers the inner peripheral surface of slinger large diameter cylindrical portion 25. Specifically, outer diameter side covering portion 29a covers the inner peripheral surface of slinger large diameter cylindrical portion 25 over the entire axial length and the entire circumference.

[0101] The slinger small diameter cylindrical portion 24a constituting the slinger 22a has an axial dimension that is shorter than that of the slinger small diameter cylindrical portion 24 of the first embodiment. The axially outer end face of the slinger small diameter cylindrical portion 24a is located radially inside the core small diameter cylindrical portion 35 constituting the core 32a of the seal ring 23a.

[0102] In this example, the core metal ring portion 36a constituting the core metal 32a has a circular flat plate shape. In addition, in this example, the axially outer surface of the core metal ring portion 36a is positioned axially outward of the axially outer end face of the slinger small-diameter cylindrical portion 24a.

[0103] The seal base 38a of the seal member 33a covers only the radially inner portion of the axially inner surface of the core ring portion 36a, leaving the radially outer portion uncovered. The seal base 38a does not cover the inner peripheral surface of the core large-diameter cylindrical portion 34.

[0104] The tip of the grease lip 39a constituting the seal material 33a is positioned closely facing the outer peripheral surface of the hub 3. However, when implementing a combined seal ring according to one embodiment of the present disclosure, the tip of the grease lip can be in sliding contact with the outer peripheral surface of the hub, or can be in sliding contact with or closely facing the outer peripheral surface of the slinger small-diameter cylindrical portion.

[0105] The seal ring 23a has a reinforcing core metal 42 in addition to the core metal 32a and the seal material 33a.

[0106] The reinforcing core 42 reinforces the core 32a. Specifically, the reinforcing core 42 reinforces the large-diameter cylindrical core portion 34 that constitutes the core 32a from the radially inner side.

[0107] The reinforcing core 42 has a cross-sectional shape that is approximately horizontally U-shaped or approximately horizontally J-shaped, and is fitted inside the large-diameter cylindrical core portion 34. In this example, the reinforcing core 42 is fitted directly inside the large-diameter cylindrical core portion 34.

[0108] The reinforcing core 42 is configured in an annular shape as a whole. The reinforcing core 42 may be made from the same type of metal plate as the core 32a, or may be made from a different type of metal plate than the core 32a.

[0109] The reinforcing core 42 has a reinforcing large-diameter cylindrical portion 43 having an outer diameter that is the same as or slightly larger than the inner diameter of the core large-diameter cylindrical portion 34 before being fitted into the outer ring 2, a reinforcing small-diameter cylindrical portion 44 arranged radially inside the reinforcing large-diameter cylindrical portion 43, and a reinforcing circular ring portion 45 connecting the axially outer end of the reinforcing large-diameter cylindrical portion 43 and the axially outer end of the reinforcing small-diameter cylindrical portion 44.

[0110] The reinforcing large-diameter cylindrical portion 43 has a cylindrical shape and is tightly fitted and fixed to the core metal large-diameter cylindrical portion 34. The axially inner portion of the reinforcing large-diameter cylindrical portion 43 is disposed radially outward of the outer diameter side cover portion 29a that covers the outer peripheral surface of the slinger large-diameter cylindrical portion 25.

[0111] The reinforcing small-diameter cylindrical portion 44 has a cylindrical shape and is arranged approximately coaxially with the reinforcing large-diameter cylindrical portion 43. The axially inner portion of the reinforcing small-diameter cylindrical portion 44 is arranged radially inner of the slinger large-diameter cylindrical portion 25. The reinforcing small-diameter cylindrical portion 44 has an axial dimension that is shorter than that of the reinforcing large-diameter cylindrical portion 43.

[0112] The reinforcing circular ring portion 45 is superimposed on the radially outer portion of the axially inner surface of the core metal circular ring portion 36a, and is arranged axially opposite the axially outer end face of the outer diameter side cover portion 29a.

[0113] In this example, the inner peripheral surface of the reinforcing large-diameter cylindrical portion 43 closely faces the outer peripheral surface of the outer diameter side covering portion 29a, forming an axial labyrinth seal 40a in the space therebetween. Also, the outer peripheral surface of the reinforcing small-diameter cylindrical portion 44 closely faces the inner peripheral surface of the outer diameter side covering portion 29a, forming an axial labyrinth seal 46 in the space therebetween. Additionally, the axial side surface of the reinforcing annular portion 45 can be closely faced to the axial outer end face of the slinger large-diameter cylindrical portion 25, forming a radial labyrinth seal in the space therebetween.

[0114] In this example, a reinforcing core 42 is fitted into the large-diameter cylindrical core portion 34, and the large-diameter cylindrical core portion 34 is reinforced from the radially inner side by the reinforcing core 42. This reduces the amount of diameter reduction that occurs in the large-diameter cylindrical core portion 34 when the large-diameter cylindrical core portion 34 is fitted into the outer ring 2. This reduces the amount of deformation that occurs in the circular core portion 36a when the large-diameter cylindrical core portion 34 is fitted into the outer ring 2. Specifically, this reduces the change in the amount of tilt (inclination angle) of the circular core portion 36a in the axial direction. This makes it easier to manage the interference of the side lip 37. This allows for a further reduction in the seal torque of the combination seal ring 5a.

[0115] In this example, not only is an axial labyrinth seal 40a provided between the inner peripheral surface of the reinforcing large-diameter cylindrical portion 43 and the outer peripheral surface of the outer-diameter side covering portion 29a, but an axial labyrinth seal 46 is also provided between the outer peripheral surface of the reinforcing small-diameter cylindrical portion 44 and the inner peripheral surface of the outer-diameter side covering portion 29a, so that the sealing performance of the combined seal ring 5a can be sufficiently ensured. Also, the durability of the side lip 37 can be improved.

[0116] Furthermore, because outer diameter side covering portion 29a of slinger 22a covers not only the outer peripheral surface and axially outer end face of slinger large-diameter cylindrical portion 25 but also the inner peripheral surface, the effects of springback and spring-go that occur when slinger 22a is formed by press working can be reduced. That is, since the molding process for processing slinger seal material 28 has smaller tolerances than press working, covering slinger large-diameter cylindrical portion 25 from the outer and inner peripheral sides with outer diameter side covering portion 29a can reduce the effects of springback and spring-go of slinger large-diameter cylindrical portion 25. Therefore, labyrinth seals 40a, 46 can exhibit sufficient sealing performance.

[0117] The configuration and effects of other parts of the second example are the same as those of the first example.

[0118] [Example 3] A third example of the embodiment of the present disclosure will be described with reference to FIG.

[0119] The combined seal ring 5b of this example is a modified example of the combined seal ring 5 of the first example.

[0120] The seal ring 23b constituting the combination seal ring 5b has an annular groove 47 that is open only axially and radially inward at a portion located radially inward of the axially inner end of the large diameter cylindrical core portion 34.

[0121] In this example, the portion of the seal base 38b that covers the inner circumferential surface of the large-diameter cylindrical core 34 is composed of a thin-walled portion 48 located at the axially inner end and a thick-walled portion 49 located in a range from the axially outer end to the axially middle portion. The inner circumferential surfaces of the thin-walled portion 48 and the thick-walled portion 49 are connected by a stepped surface 50 facing inward in the axial direction. An annular groove 47 is formed in the space surrounded by the inner circumferential surface of the portion of the seal base 38b that covers the axially inner end face of the large-diameter cylindrical core 34, the inner circumferential surface of the thin-walled portion 48, and the stepped surface 50.

[0122] In this example, the annular groove 47 has a quadrangular, specifically rectangular, cross-sectional shape. Therefore, the bottom surface (the surface facing radially inward) of the annular groove 47 is configured as a cylindrical surface. Furthermore, the stepped surface 50 is configured as a flat surface that is approximately perpendicular to the central axis of the seal ring 23b.

[0123] The slinger seal material 28a of the slinger 22b constituting the combined seal ring 5b has an annular protrusion 51 that enters the inside of the annular groove 47 from the inside in the radial direction.

[0124] The annular protrusion 51 has a circular ring shape and protrudes radially outward from the outer peripheral surface of the annular cover portion 30 that constitutes the slinger seal material 28a.

[0125] In this example, the annular protrusion 51 has a quadrangular, specifically rectangular, cross-sectional shape.

[0126] In this example, the inner circumferential surface of the portion of the seal base 38b that covers the axially inner end face of the large-diameter cylindrical core 34 and that forms the bottom surface of the annular groove 47, as well as the inner circumferential surface of the thin-walled portion 48, are closely opposed to the outer circumferential surface of the annular protrusion 51, and the stepped surface 50 that forms the inner surface of the annular groove 47 is closely opposed to the axially outer surface of the annular protrusion 51. As a result, a labyrinth seal 52 having a cross-sectional shape bent at a substantially right angle is formed between the annular groove 47 and the annular protrusion 51. In addition, an axial labyrinth seal 40b is formed between the inner circumferential surface of the thick-walled portion 49 and the outer circumferential surface of the outer-diameter side cover portion 29. The labyrinth seal 40b and the labyrinth seal 52 are in communication with each other.

[0127] The combined seal ring 5b of this example further includes a labyrinth seal 52 on the side closer to the external space 56 than the axial labyrinth seal 40b. This further improves the sealing performance of the combined seal ring 5b and the durability of the side lip 37.

[0128] The configuration and effects of other parts of the third example are the same as those of the first example.

[0129] [Example 4] A fourth example of the embodiment of the present disclosure will be described with reference to FIG.

[0130] The combined seal ring 5c ​​of this example is a modified example of the combined seal ring 5a of the second example.

[0131] Of the slinger 22b and seal ring 23c that constitute the combined seal ring 5c, the structure of the slinger 22b is the same as the structure of the slinger 22b that constitutes the combined seal ring 5b of the third example.

[0132] The seal ring 23c has an annular groove 47a that is open only axially and radially inward at a portion located radially inward of the axially inner end of the large-diameter cylindrical core portion .

[0133] In this example, the annular groove portion 47a is formed in a space surrounded by the inner surface of a gasket portion 57 of the sealing material 33a that covers the axially inner end of the core large diameter cylindrical portion 34, the inner surface of a portion of the core large diameter cylindrical portion 34 that protrudes axially inner than the reinforcing large diameter cylindrical portion 43, and the axially inner end face of the reinforcing large diameter cylindrical portion 43.

[0134] In this example, the inner peripheral surface of the gasket portion 57 and the inner peripheral surface of the portion of the large-diameter cylindrical core portion 34 that protrudes axially inward beyond the reinforcing large-diameter cylindrical portion 43, which constitute the bottom surface of the annular groove portion 47a, closely face the outer peripheral surface of the annular protrusion portion 51, and the axially inner end face of the reinforcing large-diameter cylindrical portion 43, which constitutes the inner surface of the annular groove portion 47a, closely faces the axially outer surface of the annular protrusion portion 51. As a result, a labyrinth seal 52a having a cross-sectional shape bent at a substantially right angle is formed between the annular groove portion 47a and the annular protrusion portion 51. In addition, an axial labyrinth seal 40a is formed between the inner peripheral surface of the reinforcing large-diameter cylindrical portion 43 and the outer peripheral surface of the outer-diameter side cover portion 29a. The labyrinth seal 40a and the labyrinth seal 52a are in communication with each other.

[0135] The combined seal ring 5c ​​of this example further includes a labyrinth seal 52a on the side closer to the external space 56 than the axial labyrinth seal 40a. This further improves the sealing performance of the combined seal ring 5c ​​and the durability of the side lip 37.

[0136] The configuration and effects of other parts of the fourth example are the same as those of the first, second and third examples.

[0137] [Example 5] A fifth example of the embodiment of the present disclosure will be described with reference to FIG.

[0138] The combined seal ring 5d of this example is a modified example of the combined seal ring 5b of the third example.

[0139] Of the slinger 22c and seal ring 23b that constitute the combined seal ring 5d, only the structure of the slinger 22c differs from the structure of the slinger 22b that constitutes the combined seal ring 5b of the third example.

[0140] The slinger large-diameter cylindrical portion 25a of the slinger body 27a constituting the slinger 22c is not cylindrical, but rather conical. The outer and inner diameters of the slinger large-diameter cylindrical portion 25a increase axially outward. Therefore, the outer and inner diameters of the outer diameter side cover portion 29b of the slinger seal member 28b covering the slinger large-diameter cylindrical portion 25a increase axially outward. The outer peripheral surface of the outer diameter side cover portion 29b is conical except for the portion where the annular protrusion 51a (described later) is provided. The outer peripheral surface of the annular ring cover portion 30 is also conical.

[0141] In this example, an annular protrusion 51a is provided on the axially inner side of the outer peripheral surface of the outer diameter side cover portion 29b. The annular protrusion 51a is thinner than the annular protrusion 51 of the third example and has a substantially L-shaped cross section. The annular protrusion 51a is composed of a cylindrical portion 53 that extends axially inward from the outer peripheral surface of the outer diameter side cover portion 29b and an outward flange portion 54 that bends radially outward from the axially inner end of the cylindrical portion 53. The outward flange portion 54 of the annular protrusion 51a extends inside an annular groove portion 47 provided in the seal ring 23b.

[0142] In this example, the inner circumferential surface of the portion of the seal base 38b covering the axially inner end face of the large-diameter cylindrical core portion 34, which constitutes the bottom surface of the annular groove 47, and the inner circumferential surface of the thin-walled portion 48 are closely opposed to the outer circumferential surface of the outward flange 54, and the stepped surface 50 constituting the inner surface of the annular groove 47 is closely opposed to the axially outer surface of the outward flange 54. As a result, a labyrinth seal 52b having a cross-sectional shape bent at a substantially right angle is formed between the annular groove 47 and the annular protrusion 51a. Furthermore, an axial labyrinth seal 40c that becomes thinner as it approaches the annular space 20 is formed between the inner circumferential surface of the thick-walled portion 49 and the outer circumferential surface of the outer-diameter side cover portion 29b. The labyrinth seal 40c and the labyrinth seal 52b are in communication with each other.

[0143] The outward flange 54 constituting the annular protrusion 51 a is disposed radially outward of the circular ring cover 30 , and is positioned axially outward of the axially inner surface of the circular ring cover 30 .

[0144] The inner peripheral surface of the outer diameter side covering portion 29b is configured in a circumferentially wavy shape. In other words, the inner peripheral surface of the outer diameter side covering portion 29b is provided with recessed grooves 55 extending in the radial direction at multiple locations equally spaced in the circumferential direction.

[0145] In this example, the outer peripheral surfaces of the outer diameter side covering portion 29b and the circular ring covering portion 30 are each formed as a conical cylindrical surface that is inclined in a direction such that the outer diameter becomes smaller as it moves axially inward. Therefore, when the vehicle is stopped, muddy water that drips from the outer ring 2 onto the outer peripheral surface of the outer diameter side covering portion 29b and / or the circular ring covering portion 30 can be guided to the road surface through the outer peripheral surface of the outer diameter side covering portion 29b and / or the circular ring covering portion 30.

[0146] The outward flange portion 54 that constitutes the annular protrusion portion 51a is positioned radially outside the circular ring cover portion 30 and is located axially outside the axial inner surface of the circular ring cover portion 30.Therefore, even if foreign matter such as muddy water adhering to the axial inner surface of the circular ring cover portion 30 is thrown radially outward by centrifugal force, the muddy water can be prevented from adhering to the outward flange portion 54.

[0147] In this example, the annular protrusion 51a is provided on the outer peripheral surface of the outer diameter side cover portion 29b, rather than on the outer peripheral surface of the annular ring cover portion 30 that functions as an encoder. This allows the ferrite concentration in the annular protrusion 51a to be kept lower than the ferrite concentration in the annular protrusion 51 of the third example. This ensures a large amount of elastic deformation of the annular protrusion 51a. Furthermore, in this example, the annular protrusion 51a is configured to be thinner than the annular protrusion 51 of the third example. Therefore, the rotational airflow generated when the hub 3 rotates causes the annular protrusion 51a to elastically deform so as to approach the step surface 50, allowing the annular protrusion 51a to close the labyrinth seal 52b. Furthermore, even when muddy water splashed up during vehicle travel adheres to the annular protrusion 51a, the annular protrusion 51a can elastically deform and close the labyrinth seal 52b. Therefore, the amount of muddy water that enters the labyrinth seal 40c can be reduced, and the sealing performance of the combined seal ring 5d can be further improved.

[0148] In this example, the inner circumferential surface of the outer diameter side covering portion 29b is configured in a conical cylindrical shape, so that muddy water that has entered the space on the outer diameter side of the side lip 37 within the internal space of the combined seal ring 5d can be guided to the external space 56 by using the inner circumferential surface of the outer diameter side covering portion 29b. Furthermore, the inner circumferential surface of the outer diameter side covering portion 29b is configured in a corrugated shape, and the inner circumferential surface of the outer diameter side covering portion 29b is provided with a plurality of recessed grooves 55, so that the recessed grooves 55 can be used to more effectively guide muddy water to the external space 56.

[0149] The configuration and effects of other parts of the fifth example are the same as those of the first and third examples.

[0150] [Example 6] A sixth example of the embodiment of the present disclosure will be described with reference to FIG.

[0151] The combined seal ring 5e of this example is a modified example of the combined seal ring 5c ​​of the fourth example.

[0152] Of the slinger 22c and seal ring 23c that make up the combined seal ring 5e, only the structure of the slinger 22c differs from the structure of the slinger 22b that makes up the combined seal ring 5c ​​of the fourth example. The slinger 22c of this example has the same structure as the slinger 22c that makes up the combined seal ring 5d of the fifth example. In other words, the combined seal ring 5e of this example has a structure that combines the slinger 22c of the fifth example and the seal ring 23c of the fourth example.

[0153] An outward flange 54 of an annular protrusion 51a provided on the outer peripheral surface of the outer diameter side cover portion 29b constituting the slinger 22c enters the inside of an annular groove 47a provided in the seal ring 23c.

[0154] In this example, the inner peripheral surface of the gasket portion 57 and the inner peripheral surface of the portion of the core large-diameter cylindrical portion 34 that protrudes axially inward beyond the reinforcing large-diameter cylindrical portion 43, which constitute the bottom surface of the annular groove portion 47a, closely face the outer peripheral surface of the outward flange portion 54. Also, the axially inner end face of the reinforcing large-diameter cylindrical portion 43, which constitutes the inner surface of the annular groove portion 47a, closely faces the axially outer surface of the outward flange portion 54. As a result, a labyrinth seal 52c having a cross-sectional shape bent at a substantially right angle is formed between the annular groove portion 47a and the annular protrusion 51a. Furthermore, an axial labyrinth seal 40d that tapers toward the annular space 20 is formed between the inner peripheral surface of the reinforcing large-diameter cylindrical portion 43 and the outer peripheral surface of the outer-diameter side cover portion 29b. The labyrinth seal 40d and the labyrinth seal 52c are in communication with each other.

[0155] In this example, the annular protrusion 51a can be elastically deformed to approach the step surface 50a, and the labyrinth seal 52c can be closed by the annular protrusion 51a, thereby reducing the amount of muddy water that enters the labyrinth seal 40d and further improving the sealing performance of the combination seal ring 5e.

[0156] The configuration and effects of other parts of the sixth example are the same as those of the first to fifth examples.

[0157] The first to sixth examples of the embodiment of the present disclosure can be implemented in any suitable combination as long as no contradiction occurs. [Explanation of symbols]

[0158] 1 Hub unit bearing 2 outer ring 3. Hub 4a, 4b rolling elements 5, 5a, 5b, 5c, 5d, 5e combination seal ring 6a, 6b Outer raceway 7 Stationary Flange 8 Flange side support hole 9a, 9b Inner raceway 10 Rotating flange 11 Pilot Division 12 Mounting holes 13 Studs 14 spline holes 15 Inner Circle 16 Hub wheel 17 Mating shaft 18 Step surface 19a, 19b retainer 20 Annular Space 21 Sealing device 22, 22a, 22b, 22c Slinger 23, 23a, 23b, 23c Seal rings 24, 24a Slinger small diameter cylinder 25, 25a Slinger large diameter cylinder 26 Slinger ring part 27, 27a Slinger body 28, 28a, 28b Slinger seal material 29, 29a, 29b Outer diameter side cover part 30 Circular ring cover 31 Detected surface 32, 32a Core metal 33, 33a Sealing material 34 Large diameter cylindrical core 35 Core metal small diameter cylinder part 36, 36a, 36b Core metal ring part 37 Side lip 38, 38a, 38b Seal base 39, 39a Grease Lip 40, 40a, 40b, 40c, 40d Labyrinth Seal 41 Labyrinth Seal 42 Reinforcing core 43 Reinforced large diameter cylinder 44 Reinforced small diameter cylinder 45 Reinforced circular ring 46 Labyrinth Seal 47, 47a, 47b Annular groove 48 Thin-walled section 49 Thick wall part 50, 50a step surface 51, 51a Annular protrusion 52, 52a, 52b, 52c Labyrinth seal 53 Cylindrical part 54 Outward flange 55 Groove 56 Exterior Space 57 Gasket part 100 Hub unit bearing 101 outer ring 102 Hub 103 Annular Space 104 Combination Seal Ring 105 Slinger 106 Seal ring 107 Slinger body 108 Slinger seal material 109 Slinger small diameter cylinder 110 Slinger large diameter cylinder 111 Slinger circular ring part 112 Core 113 Sealing material 114 Large diameter core cylinder 115 Core metal ring part 116 Seal base 117a, 117b Side lip 118 Grease Lip 119 Labyrinth Seal 120 Exterior Space

Claims

1. A combination seal ring is attached between an inner member and an outer member that are coaxially arranged, and closes an opening on one axial side of an annular space that exists between an outer peripheral surface of the inner member and an inner peripheral surface of the outer member, a slinger fixed to the inner member and a seal ring fixed to the outer member, The slinger has a slinger small-diameter cylindrical portion fitted onto the inner member, a slinger large-diameter cylindrical portion arranged radially outward of the slinger small-diameter cylindrical portion, and a slinger ring portion connecting one axial end of the slinger small-diameter cylindrical portion and one axial end of the slinger large-diameter cylindrical portion, The seal ring has a core metal and a seal material having only a side lip as a sliding lip that extends in a direction approaching the external space as it approaches the tip side of the core metal, the core metal has a large-diameter cylindrical core metal portion fitted into the outer member, a small-diameter cylindrical core metal portion arranged radially inside the large-diameter cylindrical core metal portion, and a core metal ring portion connecting the other axial end of the large-diameter cylindrical core metal portion and the other axial end of the small-diameter cylindrical core metal portion, In addition to the side lip, the sealing material has a seal base covering the surface of the core metal, and a grease lip extending in a direction approaching the annular space as it approaches the tip end, with the tip end closely facing or in sliding contact with the outer circumferential surface of the inner member or the slinger small-diameter cylindrical portion. Combination seal ring.

2. 2. The combination seal ring according to claim 1, wherein the side lip has a base end connected to a portion of the seal base that covers the outer peripheral surface of the small diameter cylindrical core portion, and a tip end that is in sliding contact with the side surface on the other axial side of the slinger circular ring portion.

3. 2. The combination seal ring according to claim 1, wherein the seal ring has a reinforcing core metal fitted inside the large-diameter cylindrical core metal portion.

4. the seal ring has an annular groove portion that is open only to one axial side and to the radially inner side, at a portion located radially inward of one axial end of the large-diameter cylindrical core portion, The slinger comprises a metal slinger body having the slinger small diameter cylindrical portion, the slinger large diameter cylindrical portion, and the slinger ring portion, and a slinger seal member made of an elastic material and fixed to the slinger body; The slinger seal has an annular protrusion that penetrates into the annular groove. The combination seal ring according to claim 1 .

5. an outer member having a double row outer ring raceway on its inner circumferential surface; an inner member having a double row inner ring raceway on its outer peripheral surface; a plurality of rolling elements disposed between the double row outer ring raceways and the double row inner ring raceways so as to be freely rollable; a combined seal ring that closes an opening on one axial side of an annular space that exists between an inner peripheral surface of the outer member and an outer peripheral surface of the inner member, A hub unit bearing, wherein the combined seal ring is the combined seal ring according to any one of claims 1 to 4.

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