Combination seal ring and hub unit bearing

Abstract

To provide a combination seal ring capable of improving muddy water resistance.SOLUTION: The combination seal ring 5 has a slinger 22 having a substantially horizontal U-shaped cross section, and a seal ring 23 having a side lip 35 and a bank part 36. The slinger 22 has a slinger small-diameter cylindrical portion 24, a slinger large-diameter cylindrical portion 25, and a slinger annular portion 26. The bank portion 36 has a tapered surface 43 on its inner peripheral surface at a position substantially parallel to and overlapping in the axial direction with the outer peripheral surface of the side lip 35 in an elastically deformed state of the side lip 35 in which the distal end portion of the side lip 35 is brought into sliding contact with the axially outer side surface of the slinger circular portion 26.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] Hub unit bearings are used to support automobile wheels rotatably relative to a suspension system. Because hub unit bearings are used in environments where they are directly exposed to muddy water, the opening of the annular space in which the rolling elements are installed is sealed using a sealing device such as a combination seal ring.

[0003] The combined seal ring is made up of a slinger and a seal ring and is compact. Therefore, when the combined seal ring is used as a sealing device, the installation space can be reduced and the distance between the rows of rolling elements that make up the hub unit bearing can be increased. Therefore, the use of the combined seal ring can contribute to improving the bearing life of the hub unit bearing.

[0004] On the other hand, because combination seal rings are small, the thickness of the seal lip provided on the seal ring is thin. A thin seal lip is advantageous in terms of keeping the seal torque low, but if muddy water splashes on the seal lip with force, the seal lip may curl up, making it difficult to ensure sealing performance. Thus, combination seal rings are required to ensure sealing performance even when muddy water splashes on them while the vehicle is running.

[0005] FIG. 8 shows a hub unit bearing 100 of a conventional structure described in Japanese Patent Application Laid-Open No. 2023-97884.

[0006] 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.

[0007] The combination seal ring 104 includes a slinger 105 and a seal ring 106 .

[0008] Slinger 105 has a substantially horizontal U-shaped cross section and is fixed to hub 102. Slinger 105 has a slinger small diameter cylindrical portion 107 fitted onto the outside of hub 102, a slinger large diameter cylindrical portion 108 arranged radially outward of slinger small diameter cylindrical portion 107, and a slinger ring portion 109 connecting the axially inner end of slinger small diameter cylindrical portion 107 and the axially inner end of slinger large diameter cylindrical portion 108.

[0009] The seal ring 106 is fixed to the outer ring 101. The seal ring 106 has a cylindrical seal portion 110 fitted inside the outer ring 101, and a circular seal portion 111 extending radially inward from the axially outer end of the cylindrical seal portion 110.

[0010] The inner peripheral surface of the cylindrical seal portion 110 closely faces the outer peripheral surface of the large-diameter cylindrical slinger portion 108 over the entire circumference, thereby forming a first labyrinth seal 112 between the inner peripheral surface of the cylindrical seal portion 110 and the outer peripheral surface of the large-diameter cylindrical slinger portion 108.

[0011] The seal ring 106 has a side lip 113 whose tip is in sliding contact with the axially outer surface of the slinger ring portion 109. The side lip 113 has a conical cylindrical shape. The base end of the side lip 113 is connected to the inner peripheral surface of the seal ring portion 111, and it extends radially outward as it moves axially inward.

[0012] The seal ring 106 has a bank portion 114 disposed radially between the side lip 113 and the slinger large-diameter cylindrical portion 108. The bank portion 114 has an annular shape.

[0013] The bank portion 114 has a flange portion 115 at its axially inner end that protrudes radially outward. The outer peripheral surface (tip surface) of the flange portion 115 closely faces the inner peripheral surface of the slinger large-diameter cylindrical portion 108 over the entire circumference. As a result, a second labyrinth seal 116 is formed between the outer peripheral surface of the flange portion 115 and the inner peripheral surface of the slinger large-diameter cylindrical portion 108.

[0014] The combined seal ring 104 is provided with the bank portion 114 so as to cover the side lip 113 from the radially outer side, so that muddy water can be prevented from splashing forcefully onto the side lip 113.

[0015] Additionally, the combined seal ring 104 has a first labyrinth seal 112 between the inner peripheral surface of the cylindrical seal portion 110 and the outer peripheral surface of the large-diameter cylindrical slinger portion 108, and a second labyrinth seal 116 between the outer peripheral surface of the flange portion 115 and the inner peripheral surface of the large-diameter cylindrical slinger portion 108. This reduces the force of muddy water entering and prevents the muddy water from splashing forcefully onto the side lip 113.

[0016] Therefore, the combined seal ring 104 of the conventional structure can ensure sealing performance even when muddy water splashes onto it. [Prior art documents] [Patent documents]

[0017] [Patent Document 1] Japanese Patent Application Publication No. 2023-97884 Summary of the Invention [Problem to be solved by the invention]

[0018] In the combined seal ring 104 of the conventional structure, the outer peripheral surface of the side lip 113 and the inner peripheral surface of the bank portion 114 are separated from each other in the radial direction by a large distance, so the volume of the storage space 117 formed between the outer peripheral surface of the side lip 113 and the inner peripheral surface of the bank portion 114 for temporarily storing muddy water is large. As a result, the area of ​​the opposing portion 118 of the axially outer surface of the slinger annular portion 109 that faces the opening of the storage space 117 is large.

[0019] As a result, when muddy water that has entered the interior of the combined seal ring 104 reaches the sliding contact portion between the tip of the side lip 113 and the axially outer surface of the slinger circular ring portion 109, the muddy water is drawn around by the rotating axially outer surface (opposing portion 118) of the slinger circular ring portion 109, making it more likely that a rotating water flow will occur. This makes it more likely that the flow rate of muddy water passing near the sliding contact portion will increase. The rotating water flow generates a hydrodynamic force that tries to turn up the side lip 113, making it more likely that the sealing performance of the side lip 113 will be reduced.

[0020] As described above, the combined seal ring 104 of the conventional structure still has room for improvement in terms of muddy water resistance.

[0021] An object of the present disclosure is to provide a combination seal ring that can improve muddy water resistance. [Means for solving the problem]

[0022] A combination seal ring according to one aspect of the present disclosure is mounted between an inner member and an outer member that are coaxially arranged, and closes the opening of an annular space that exists between the outer peripheral surface of the inner member and the inner peripheral surface of the outer member.

[0023] A combination seal ring according to one aspect of the present disclosure includes a slinger fixed to the inner member and a seal ring fixed to the outer member.

[0024] The slinger has a cross-sectional shape that is approximately horizontally U-shaped, and includes a slinger small-diameter cylindrical portion fitted onto the inner member, a slinger large-diameter cylindrical portion 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.

[0025] The seal ring has a conical cylindrical shape and a side lip whose tip is in sliding contact with the other axial side of the slinger ring portion, and a dam portion having an annular shape and arranged radially between the side lip and the slinger large diameter cylindrical portion.

[0026] The embankment portion has a tapered surface on its inner surface that is arranged approximately parallel to and overlaps in the axial direction with the outer surface of the side lip when the side lip is in an elastically deformed state with the tip of the side lip sliding against the other axial side of the slinger ring portion.

[0027] In one embodiment of the combined seal ring of the present disclosure, the distance between the tapered surface and the outer peripheral surface of the side lip, which are arranged approximately parallel to each other, can be approximately the same size as the thickness of the side lip.

[0028] In one embodiment of the combined seal ring of the present disclosure, the inner surface of the large diameter slinger cylindrical portion can have a drain groove that is recessed radially outward at a position that radially overlaps with the end of one axial side of the embankment portion and that opens to the end face on the other axial side of the large diameter slinger cylindrical portion.

[0029] 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 the opening of an annular space that exists 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]

[0030] According to the combination seal ring according to one aspect of the present disclosure, muddy water resistance can be improved. [Brief explanation of the drawings]

[0031] [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 a cross-sectional view of the combined seal ring of the first example, showing the side lip and the grease lip in a free state. [Figure 3] FIG. 3 is a cross-sectional view of the combined seal ring of the first example, showing the side lip and the grease lip in an elastically deformed state. [Figure 4] FIG. 4 is a diagram corresponding to FIG. 2 and illustrating a second example of an embodiment of the present disclosure. [Figure 5] FIG. 5 is a diagram corresponding to FIG. 3 and illustrating a second example of an embodiment of the present disclosure. [Figure 6] FIG. 6 is a diagram corresponding to FIG. 2 and illustrating a third example of an embodiment of the present disclosure. [Figure 7] FIG. 7 is a diagram corresponding to FIG. 3 and relating to a third example of an embodiment of the present disclosure. [Figure 8] FIG. 8 is a partial cross-sectional view of a hub unit bearing having a conventional structure. DETAILED DESCRIPTION OF THE INVENTION

[0032] [Example 1] A first example of an embodiment of the present disclosure will be described with reference to FIGS. 1 to 3. FIG.

[0033] [Overall structure of hub unit bearing] The hub unit bearing 1 includes an outer ring 2 corresponding to the outer member, a hub 3 corresponding to the inner member, a plurality of rolling elements 4a, 4b, and a combined seal ring 5. The hub unit bearing 1 is an inner ring rotating type hub unit bearing.

[0034] The hub unit bearing 1 of this example is a so-called third-generation hub unit bearing for a driving wheel. However, a hub unit bearing according to one embodiment of the present disclosure can also be applied to a hub unit bearing for a driven wheel, as well as first- and second-generation hub unit bearings.

[0035] 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.

[0036] The outer ring 2 is made of a hard metal such as medium carbon steel. The outer ring 2 has a generally cylindrical shape and has double-row angular outer ring raceways 7a, 7b on its inner circumferential surface. The outer ring 2 has a stationary flange 8 that protrudes radially outward at an axially intermediate portion. The stationary flange 8 has support holes 9 that penetrate the axial direction at multiple circumferential locations at the radially intermediate portion.

[0037] In this example, the support holes 9 are configured as threaded holes. The outer ring 2 is supported and fixed to the suspension by threading a support bolt, which is inserted through a through hole provided in the knuckle of the suspension, into the support hole 9 of the stationary flange 8 from the inside in the axial direction, so that the outer ring 2 does not rotate even when the wheel rotates.

[0038] The hub 3 is disposed coaxially with the outer ring 2 and radially inward of the outer ring 2. The hub 3 has angular double-row inner ring raceways 10a, 10b on its outer peripheral surface. The hub 3 has a rotating flange 11 that protrudes radially outward at a portion that protrudes axially outward beyond the outer ring 2. The hub 3 has a cylindrical pilot portion 12 at its axially outer end. Furthermore, the hub 3 has a spline hole 13 in its radial center that penetrates the hub 3 in the axial direction.

[0039] The rotating flange 11 has mounting holes 14 that penetrate the axial direction at multiple locations circumferentially in the radially middle portion. Studs 15 for connecting and fixing a braking rotor such as a disc or drum and a wheel that constitutes a wheel to the rotating flange 11 are press-fitted into each mounting hole 14 with serrations. That is, in this example, the mounting holes 14 are cylindrical holes.

[0040] A braking rotating body such as a brake disc and a wheel of a vehicle are connected and fixed to the rotating flange 11 by inserting a pilot portion 12 into a central hole provided in the center of each and inserting studs 15 into through holes provided at multiple locations circumferentially in the radially middle portion of each, and then screwing a hub nut onto the tip of the stud 15.

[0041] The mounting holes of the rotating flange can also be threaded holes. In this case, the braking rotor and wheel are connected and fixed to the rotating flange by threading a hub bolt, which passes through a through hole provided in the braking rotor and a through hole provided in the wheel, into the mounting hole from the outside in the axial direction.

[0042] The tip of a drive shaft that is rotated and driven by an engine or electric motor as a drive source is spline-engaged with the spline hole 13. When the vehicle is running, the hub 3 is rotated by the drive shaft, which rotates and drives the wheels and braking rotors that are coupled and fixed to the rotating flange 11 of the hub 3.

[0043] The hub 3 is configured by combining an inner ring 16 and a hub ring 17 .

[0044] The inner ring 16 is made of a hard metal such as bearing steel and has an annular shape. The inner ring 16 has an inner ring raceway 10b on the axially inner side on its outer circumferential surface.

[0045] The hub ring 17 is made of a hard metal such as medium carbon steel, and includes an inner ring raceway 10a on the axially outer side, a rotation flange 11, a pilot portion 12, and a spline hole 13.

[0046] The hub ring 17 has a small diameter step 18, which has a smaller outer diameter than the adjacent axially outer portion, at a portion located axially more inward than the axially outer inner ring raceway 10a. The hub ring 17 has a step surface 19, facing axially inward, at the axially outer end of the small diameter step 18.

[0047] The inner ring 16 is fitted onto the small diameter step 18 of the hub ring 17 with an interference fit, and its axially outer end face abuts against a step surface 19 of the hub ring 17. In this way, the hub ring 17 and the inner ring 16 are joined and fixed together.

[0048] In this example, the hub wheel and inner ring are joined and fixed together by clamping the inner ring from both axial sides between the stepped surface of the hub wheel and the axially outer surface of an outer ring shoulder provided on the drive shaft that is inserted into the splined hole of the hub wheel. Note that the hub wheel and inner ring for driven wheels can also be joined and fixed together 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 screwed onto the axially inner end of the hub wheel.

[0049] The rolling elements 4a, 4b are made of hard metal such as bearing steel or ceramics. The rolling elements 4a, 4b are arranged between the double-row outer ring raceways 7a, 7b and the double-row inner ring raceways 10a, 10b, with multiple rolling elements in each row spaced apart in the circumferential direction. The rolling elements 4a, 4b are held in a freely rolling manner by cages 20a, 20b. In this example, balls are used as the rolling elements 4a, 4b, but tapered rollers can also be used as the rolling elements. The rolling elements 4a, 4b arranged in double rows are given a back-to-back (DB) type contact angle.

[0050] 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 rolling elements in the axially outer row and the pitch circle diameter of the rolling elements 4b in the axially inner row are equal. However, a hub unit bearing according to one embodiment of the present disclosure can also be applied to a so-called different diameter PCD type structure in which the pitch circle diameter of the rolling elements 4a in the axially outer row and the pitch circle diameter of the rolling elements 4b in the axially inner row are different.

[0051] The combined seal ring 5 closes the axially inner opening of the annular space 21 that exists between the inner peripheral surface of the outer ring 2 and the outer peripheral surface of the hub 3. Therefore, 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.

[0052] However, when implementing a hub unit bearing according to one aspect of the present disclosure, the combined seal ring can also 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.

[0053] Hub unit bearing 1 of this example further includes a seal ring 6 that closes an opening on the axially outer side of annular space 21. When implementing a hub unit bearing according to an embodiment of the present disclosure, the structure of the sealing device that closes openings other than the opening that is closed by the combined seal ring according to an embodiment of the present disclosure is not limited to the structure shown in the figure.

[0054] The combined seal ring 5 and the seal ring 6 prevent leakage of grease (not shown) sealed in the annular space 21 and also prevent foreign matter such as muddy water from entering the annular space 21 .

[0055] [Structure of combined seal ring] The combination seal ring 5 has a slinger 22 and a seal ring 23 .

[0056] The slinger 22 is fixed to the hub 3 and rotates during use, whereas the seal ring 23 is fixed to the outer ring 2 and does not rotate during use.

[0057] Slinger Slinger 22 has a cross-sectional shape that is roughly a horizontal U. Slinger 22 has a slinger small-diameter cylindrical portion 24 fitted onto hub 3, a slinger large-diameter cylindrical portion 25 disposed radially outward of slinger small-diameter cylindrical portion 24, and a slinger ring portion 26 connecting the axially inner end of slinger small-diameter cylindrical portion 24 and the axially inner end of slinger large-diameter cylindrical portion 25.

[0058] In this example, the slinger small diameter cylindrical portion 24 is fitted onto the outer surface of the inner ring 16 that constitutes the hub 3. Specifically, the slinger small diameter cylindrical portion 24 is fitted onto the outer surface of the inner ring 16 by an interference fit.

[0059] The slinger small diameter cylindrical portion 24 and the slinger large diameter cylindrical portion 25 are arranged coaxially with each other and each have a cylindrical shape. The axial dimension of the slinger small diameter cylindrical portion 24 is larger than the axial dimension of the slinger large diameter cylindrical portion 25.

[0060] The outer peripheral surface of the slinger large diameter cylindrical portion 25 is formed in a cylindrical shape except for both axial ends.

[0061] The axially inner surface of the slinger ring portion 26 is configured as a flat surface existing on an imaginary plane perpendicular to the central axis of the slinger 22, except for both radially opposite ends.

[0062] In this example, the slinger 22 is composed of a core (encoder core) 28 and an encoder body 29 fixed to the core 28. However, when implementing a combined seal ring according to one aspect of the present disclosure, the slinger may also be composed of only the core.

[0063] The core 28 is made of a magnetic metal plate and has a cross-sectional shape that is roughly a horizontal U. The core 28 has a small-diameter cylindrical core portion 30 fitted onto the inner ring 16, a large-diameter cylindrical core portion 31 disposed radially outside the small-diameter cylindrical core portion 30, and a core ring portion 32 connecting the axially inner end of the small-diameter cylindrical core portion 30 and the axially inner end of the large-diameter cylindrical core portion 31.

[0064] The small diameter cylindrical core portion 30 and the large diameter cylindrical core portion 31 are arranged coaxially with each other and each have a cylindrical shape. The axial dimension of the small diameter cylindrical core portion 30 is larger than the axial dimension of the large diameter cylindrical core portion 31.

[0065] The encoder body 29 is made of a permanent magnet and has a substantially L-shaped cross section. The encoder body 29 has a disk-shaped cover 33 that covers the axially inner surface of the core metal ring portion 32, and a cylindrical cover 34 that covers the outer peripheral surface of the core metal large-diameter cylindrical portion 31. In this example, the cylindrical cover 34 covers not only the outer peripheral surface of the core metal large-diameter cylindrical portion 31, but also the axially outer end face of the core metal large-diameter cylindrical portion 31. On the axially inner surface of the disk-shaped cover 33, south poles and north poles are arranged alternately in the circumferential direction, and the axially inner surface of the disk-shaped cover 33 functions as a detection surface.

[0066] In this example, the slinger small diameter cylindrical portion 24 is composed only of a small diameter cylindrical core portion 30. In contrast, the slinger large diameter cylindrical portion 25 is composed of a large diameter cylindrical core portion 31 and a cylindrical covering portion 34, and the slinger circular ring portion 26 is composed of a circular core portion 32 and a disk-shaped covering portion 33.

[0067] <Seal ring> The seal ring 23 includes a side lip 35 having a conical cylindrical shape and a ring-shaped bank portion 36. The bank portion 36 serves to prevent muddy water from splashing against the side lip 35 with force.

[0068] In this example, the seal ring 23 has a cylindrical seal portion 37 fitted into the outer ring 2 and a circular seal portion 38 extending radially inward from the axially outer end of the cylindrical seal portion 37.

[0069] The cylindrical seal portion 37 is fitted into the axially inner end portion of the outer ring 2. Specifically, the cylindrical seal portion 37 is fitted into the outer ring 2 by an interference fit.

[0070] The inner peripheral surface of the tubular seal portion 37 is configured to have a substantially cylindrical shape. The inner diameter of the tubular seal portion 37 is slightly larger than the outer diameter of the slinger large-diameter tubular portion 25 (tubular cover portion 34) that constitutes the slinger 22. The inner peripheral surface of the tubular seal portion 37 closely faces the outer peripheral surface of the slinger large-diameter tubular portion 25 over the entire circumference. As a result, a first labyrinth seal 39 extending in the axial direction is formed between the inner peripheral surface of the tubular seal portion 37 and the outer peripheral surface of the slinger large-diameter tubular portion 25.

[0071] The axially inner surface of the seal ring portion 38 is configured as a flat surface that exists on an imaginary plane perpendicular to the central axis of the seal ring 23. The radially outer portion of the axially inner surface of the seal ring portion 38 closely faces the axially outer end face of the slinger large-diameter cylindrical portion 25 over the entire circumference. As a result, a second labyrinth seal 40 that extends radially is formed between the axially inner surface of the seal ring portion 38 and the axially outer end face of the slinger large-diameter cylindrical portion 25.

[0072] The seal ring 23 has a side lip 35 and a grease lip 41 as sliding lips that bring its tip into sliding contact with the slinger 22. The seal ring 23 of this example does not have a dust lip (axial lip, radial lip) that provides a large radial interference between it and the slinger. Note that Fig. 2 shows the side lip 35 and the grease lip 41 in a free state, and Fig. 3 shows the side lip 35 and the grease lip 41 in an elastically deformed state.

[0073] In this example, the seal ring 23 has one side lip 35 and one grease lip 41. However, when implementing a hub unit bearing according to one aspect of the present disclosure, the seal ring may have two or more side lips, or may have a dust lip.

[0074] The side lip 35 has a conical cylindrical shape. The base end of the side lip 35 is connected to the inner peripheral surface of the seal ring portion 38, and extends radially outward as it moves axially inward. The tip end of the side lip 35 is in sliding contact with the axially outer surface of the slinger ring portion 26 that constitutes the slinger 22. Specifically, the tip end of the side lip 35 is in sliding contact with a radially intermediate portion or a radially outer portion of the axially outer surface of the core metal ring portion 32 that constitutes the slinger ring portion 26. Note that with respect to the side lip 35, the base end refers to the axially outer end of the side lip 35, and the tip end refers to the axially inner end of the side lip 35.

[0075] The inclination angle of the side lip 35 with respect to the central axis of the seal ring 23 is larger in an elastically deformed state in which the tip of the side lip 35 is in sliding contact with the axially outer surface of the slinger ring portion 26 than in a free state of the side lip 35. In the illustrated example, the inclination angle of the side lip 35 is approximately 30 degrees in the free state of Fig. 2 and approximately 60 degrees in the elastically deformed state of Fig. 3. However, when implementing a combined seal ring according to one embodiment of the present disclosure, the inclination angle of the side lip is not limited to the structure of this example.

[0076] In this example, the side lip 35 has a substantially constant thickness T 35 (See Figure 2.) The thickness is almost constant when the thickness of the thinnest part is T MIN The thickness of the thickest part is T MAX In this example, the thickness T 35 is 0.3 mm or more and 1.0 mm or less.

[0077] The side lip 35 has a lip inflection point 42 on the outer peripheral surface near the tip. In an elastically deformed state, the inclination angle of the generatrix (tangent) of the outer peripheral surface of the side lip 35 relative to the central axis of the seal ring 23 is larger at the base end side of the lip inflection point 42 than at the tip end side of the lip inflection point 42.

[0078] The thickness T of the side lip 35 on the base end side from the position where the lip inflection point 42 is provided 35 In contrast, the thickness of the portion of the side lip 35 on the tip side of the position where the lip inflection point 42 is provided gradually decreases toward the tip side.

[0079] However, when implementing a combination seal ring according to an aspect of the present disclosure, the side lip does not have to have an inflection point on its outer peripheral surface. Also, if the side lip has an inflection point on its outer peripheral surface, the thickness of the portion of the side lip that is closer to the base end than the position where the lip inflection point is provided does not have to change from the base end to the tip end, or it may increase or decrease from the base end to the tip end.

[0080] The grease lip 41 is thinner than the side lip 35 and has a conical cylindrical shape. The base end of the grease lip 41 is connected to the inner peripheral surface of the seal ring portion 38, and extends axially outward as it moves radially inward. The tip end of the grease lip 41 is in sliding contact with the outer peripheral surface of the slinger small-diameter cylindrical portion 24 that constitutes the slinger 22. Specifically, the tip end of the grease lip 41 is in sliding contact (light contact) with the outer peripheral surface of the core small-diameter cylindrical portion 30 that constitutes the slinger small-diameter cylindrical portion 24. Note that with respect to the grease lip 41, the base end refers to the radially outer end of the grease lip 41, and the tip end refers to the radially inner end of the grease lip 41.

[0081] Since the grease lip 41 is a lip specialized for the function of preventing grease leakage from the annular space 21, the clamping margin with respect to the slinger small diameter cylindrical portion 24 (core small diameter cylindrical portion 30) is sufficiently smaller than that of a dust lip, which functions to prevent the intrusion of foreign matter.

[0082] The bank portion 36 is disposed radially between the side lip 35 and the slinger large-diameter cylindrical portion 25. The base end of the bank portion 36 is connected to the radially inner portion of the axially inner surface of the seal ring portion 38, and protrudes axially inward. The bank portion 36 has a tapered cross-sectional shape. Note that with respect to the bank portion 36, the base end refers to the axially outer end of the bank portion 36, and the tip end refers to the axially inner end of the bank portion 36.

[0083] In this example, the inner diameter of the base end of the bank portion 36 is slightly larger than the outer diameter of the base end of the side lip 35, and is sufficiently smaller than the outer diameter of the tip end of the side lip 35 in an elastically deformed state where the tip end of the side lip 35 is in sliding contact with the axially outer surface of the slinger ring portion 26, as shown in Figure 3. The inner diameter of the tip end of the bank portion 36 is slightly larger than the outer diameter of the tip end of the side lip 35 in an elastically deformed state.

[0084] The bank portion 36 has a tapered surface 43 on its inner peripheral surface. The tapered surface 43 is disposed in a position that is approximately parallel to and overlaps in the axial direction with the outer peripheral surface of the side lip 35 when the side lip 35 is in an elastically deformed state with the tip of the side lip 35 in sliding contact with the axial outer surface of the slinger ring portion 26.

[0085] In this example, the tapered surface 43 is disposed approximately parallel to a portion of the outer circumferential surface of the side lip 35 in an elastically deformed state that is closer to the base end than the lip inflection point 42. In the illustrated example, the inclination angle of the tapered surface 43 with respect to the central axis of the seal ring 23 is approximately 60 degrees. The inclination angle of the tapered surface is changed so as to be approximately parallel to the outer circumferential surface of the side lip in accordance with the inclination angle of the generatrix of the outer circumferential surface of the side lip in an elastically deformed state.

[0086] Note that the tapered surface 43 and the outer peripheral surface of the side lip 35 being substantially parallel means that the inclination angle (maximum value) of the generatrix of the tapered surface 43 with respect to the generatrix of the outer peripheral surface of the side lip 35 is 10 degrees or less, more preferably 5 degrees or less. In addition, the tapered surface 43 and the outer peripheral surface of the side lip 35 being substantially parallel also includes the case where the tapered surface 43 and the outer peripheral surface of the side lip 35 are both curved surfaces.

[0087] In this example, the tapered surface 43 is configured as a truncated cone surface having a linear generatrix shape. However, when implementing a combined seal ring according to one aspect of the present disclosure, the tapered surface may be configured as a curved surface having a substantially arc-shaped generatrix shape, or may be configured as a compound surface formed by combining multiple surfaces having different radii of curvature or different angles of inclination relative to the central axis of the seal ring.

[0088] In this example, the tapered surface 43 is disposed at a position overlapping in the axial direction with the entire outer peripheral surface of the side lip 35 in an elastically deformed state. However, when implementing a combined seal ring according to one aspect of the present disclosure, it is sufficient that the tapered surface is disposed at a position overlapping in the axial direction with at least a portion of the outer peripheral surface of the side lip in an elastically deformed state.

[0089] In this example, the inner peripheral surface of the bank portion 36 is mostly formed of a tapered surface 43 .

[0090] The inner peripheral surface of the bank portion 36 is composed of a tapered surface 43 and a cylindrical surface 44. The tapered surface 43 is provided on the inner peripheral surface of the bank portion 36 from the base end to the middle portion, and the cylindrical surface 44 is provided on the inner peripheral surface of the bank portion 36 at the tip end.

[0091] A storage space 45 is formed between the inner peripheral surface of the bank portion 36 and the outer peripheral surface of the side lip 35 in an elastically deformed state.

[0092] In this example, the storage space 45 consists of a rear space 46 provided between the tapered surface 43 and the portion of the outer surface of the side lip 35 that is closer to the base end than the lip inflection point 42, and an opening side space 47 provided between the tapered surface 43 and the cylindrical surface 44 and the portion of the outer surface of the side lip 35 that is closer to the tip end than the lip inflection point 42.

[0093] The distance W between the tapered surface 43 and the outer peripheral surface of the side lip 35, which are arranged approximately parallel to each other, i.e., the distance W between the tapered surface 43 and the portion of the outer peripheral surface of the side lip 35 that is closer to the base end than the lip inflection point 42 (see Figure 3), corresponds to the width dimension of the rear space 46 and is approximately constant throughout the depth direction extending along the tapered surface 43.

[0094] In this example, the distance W is the thickness T of the side lip 35. 35 is almost the same size as (W≒T 35 ) Note that the spacing W and thickness T 35 The distance W is approximately the same as the thickness T 35 It means that the ratio is 60% or more and 120% or less, more preferably 80% or more and 100% or less.

[0095] The distance between the tapered surface 43 and the portion of the outer circumferential surface of the side lip 35 that is on the tip side of the lip inflection point 42 increases toward the opening side of the storage space 45.

[0096] In this example, the outer peripheral surface of the bank portion 36 is configured to have a cylindrical surface. The outer diameter of the bank portion 36 is smaller than the inner diameter of the slinger large-diameter cylindrical portion 25 (core metal large-diameter cylindrical portion 31) that constitutes the slinger 22. When implementing a combined seal ring according to one aspect of the present disclosure, the outer peripheral surface of the bank portion can be positioned closely opposite the inner peripheral surface of the slinger large-diameter cylindrical portion over the entire circumference, thereby forming a labyrinth seal that extends in the axial direction between the outer peripheral surface of the bank portion and the inner peripheral surface of the slinger large-diameter cylindrical portion.

[0097] The tip surface (axially inner end surface) of the bank portion 36 is configured as a flat surface existing on an imaginary plane perpendicular to the central axis of the seal ring 23. The tip surface of the bank portion 36 closely faces the axially outer surface of the slinger ring portion 26 (core ring portion 32) over the entire circumference. As a result, a third labyrinth seal 48 extending radially is formed between the tip surface of the bank portion 36 and the axially outer surface of the slinger ring portion 26.

[0098] The thickness (radial thickness) T at the base end of the bank portion 36 A (See Figure 2) is the thickness T of the side lip 3535 is sufficiently larger than (T A >T 35 ) The thickness T of the base end of the bank portion 36 A The thickness of the side lip is 35mm. 35 The thickness T at the tip of the bank portion 36 is about 2 to 6 times. B (See Figure 2) is the thickness T of the side lip 35 35 Same as or side lip thickness T 35 is greater than.

[0099] In this example, the bank portion 36 is composed of a bank portion main body 49 having a generally trapezoidal cross-sectional shape and a protruding portion 50 having a generally rectangular cross-sectional shape. The bank portion main body 49 is provided in a range extending from the base end of the bank portion 36 to the portion near the tip. The protruding portion 50 is provided at the tip portion of the bank portion 36. The protruding portion 50 protrudes radially outward from the tip portion of the side lip 35 in an elastically deformed state.

[0100] The inner peripheral surface of the bank portion main body 49 is formed by a tapered surface 43. The inner peripheral surface of the overhanging portion 50 is formed by a cylindrical surface 44. The axially inner end surface of the overhanging portion 50 forms the tip surface of the bank portion 36. The outer peripheral surfaces of the bank portion main body 49 and the overhanging portion 50 form the outer peripheral surface of the bank portion 36.

[0101] In this example, the seal ring 23 is composed of a seal core metal 51 and a seal material 52 fixed to the seal core metal 51 .

[0102] The seal core metal 51 is made of a metal plate such as a cold-rolled steel plate, and has a substantially L-shaped cross section.

[0103] The seal core 51 comprises a core tube portion 53 fitted into the axially inner end of the outer ring 2, and a core flange portion 54 extending radially inward from the axially outer end of the core tube portion 53.

[0104] The core metal flange portion 54 of this example has a generally crank-shaped cross section in which the radially inner portion is offset axially inward from the radially outer portion.

[0105] The seal material 52 is made of an elastic material such as an elastomer like rubber, and has a seal base 55 , a side lip 35 , a bank 36 , and a grease lip 41 .

[0106] The seal base 55 covers the surface of the seal core 51. Specifically, the seal base 55 covers the inner peripheral surface, the axially inner end portion of the outer peripheral surface, and the axially inner end face of the core tube portion 53, and also covers the axially inner side surface, the radially inner portion of the axially outer surface, and the inner peripheral surface of the core flange portion 54.

[0107] The portion of the seal base 55 that covers the inner peripheral surface of the core metal tube portion 53 is configured in a substantially cylindrical shape, and constitutes the inner peripheral surface of the seal tube portion 37. The portion of the seal base 55 that covers the axial inner surface of the core metal flange portion 54 is configured in a flat shape, and constitutes the axial inner surface of the seal ring portion 38.

[0108] 3, when the combined seal ring 5 is mounted on the hub unit bearing 1, the side lip 35 and the grease lip 41 each undergo elastic deformation. Specifically, the side lip 35 undergoes elastic deformation so that the inclination angle with respect to the central axis of the seal ring 23 increases, and the grease lip 41 undergoes elastic deformation so that the inclination angle with respect to the central axis of the seal ring 23 decreases.

[0109] According to the combined seal ring 5 of this embodiment, it is possible to improve resistance to muddy water.

[0110] The combined seal ring 5 is provided with a bank portion 36 disposed in the seal ring 23 radially between the side lip 35 and the slinger large-diameter cylindrical portion 25. As a result, the side lip 35 is covered from the radial outside by the bank portion 36, preventing muddy water from splashing against the side lip 35 with force.

[0111] The bank portion 36 has, on its inner peripheral surface, a tapered surface 43 that is substantially parallel to and overlaps the outer peripheral surface of the side lip 35 in the elastically deformed state, with the tip of the side lip 35 in sliding contact with the axially outer surface of the slinger ring portion 26. This reduces the volume of the storage space 45 formed between the tapered surface 43 and the outer peripheral surface of the side lip 35 in the elastically deformed state. This reduces the amount of muddy water temporarily stored in the storage space 45, and also reduces the area of ​​a facing portion 56 of the axially outer surface of the slinger ring portion 26 (core ring portion 32) that faces the opening of the storage space 45. Therefore, even if muddy water penetrates into the combination seal ring 5 and reaches the sliding contact portion between the tip of the side lip 35 and the axially outer surface of the slinger ring portion 26, a rotating water flow is unlikely to occur. This also reduces the flow rate of muddy water passing near the sliding contact portion. As a result, the sealing performance of the side lip 35 can be prevented from being reduced, and the muddy water resistance of the combination seal ring 5 is improved.

[0112] In this example, the distance W between the tapered surface 43 and the outer peripheral surface of the side lip 35, which are arranged approximately parallel to each other, is 35 Therefore, when the hub 3 tilts relative to the outer ring 2 while the vehicle is running, it is possible to prevent the outer peripheral surface of the side lip 35 from coming into contact with the tapered surface 43 of the bank portion 36, which would otherwise be caused by the distance W being too small. Furthermore, muddy water that reaches the sliding contact portion between the tip end of the side lip 35 and the axially outer surface of the slinger ring portion 26 can be temporarily stored in the storage space 45, and when the vehicle is stopped, it can be discharged to the outside of the combined seal ring 5 via the route of the storage space 45 → third labyrinth seal 48 → second labyrinth seal 40 → first labyrinth seal 39.

[0113] In this example, the inner circumferential surface of the bank portion 36 has a tapered surface 43 connected to the seal ring portion 38, the inner diameter of which decreases axially outward, ensuring a sufficient thickness at the base end portion and increasing radial rigidity. This prevents the bank portion 36 from bending radially inward even when muddy water adheres to the outer circumferential surface of the bank portion 36. This reduces the amount of muddy water that reaches the sliding contact area between the tip of the side lip 35 and the axially outer surface of the slinger ring portion 26.

[0114] In this example, the muddy water must pass through the first labyrinth seal 39, the second labyrinth seal 40 and the third labyrinth seal 48 before reaching the sliding contact point between the tip of the side lip 35 and the axially outer surface of the slinger circular ring portion 26, and because the path to the sliding contact point is complex and long, the amount of muddy water that reaches the sliding contact point is sufficiently small.

[0115] In addition, the embankment 36 is composed of a embankment main body 49 having an approximately trapezoidal cross-sectional shape and a protruding portion 50 having an approximately rectangular cross-sectional shape, and the protruding portion 50 covers the tip of the side lip 35 in an elastically deformed state from the radial outside, thereby preventing muddy water from splashing forcefully onto the tip of the side lip 35 compared to when the embankment is composed only of the embankment main body.

[0116] In this example, the storage space 45 is inclined in the radial direction with respect to the axial direction, so that muddy water that has entered the storage space 45 can be effectively discharged when the vehicle is stopped.

[0117] [Example 2] A second example of the embodiment of the present disclosure will be described with reference to FIGS.

[0118] In this example, the structure of the bank portion 36a of the seal ring 23a constituting the combination seal ring 5a is different from the structure of the bank portion 36 of the first example.

[0119] The bank portion 36a is composed only of a bank portion main body 49 having a substantially trapezoidal cross section and does not have a protruding portion at its tip. The amount of protrusion of the bank portion 36a inward in the axial direction is smaller than the amount of protrusion of the bank portion 36 in the first example. Therefore, in this example, no labyrinth seal is formed between the tip surface of the bank portion 36a and the axially outer surface of the slinger ring portion 26. The inner diameter of the tip of the bank portion 36a is smaller than the outer diameter of the tip of the side lip 35 in an elastically deformed state.

[0120] The tapered surface 43a provided on the inner peripheral surface of the bank portion 36a is disposed in a position that is substantially parallel to the outer peripheral surface of the side lip 35 in the elastically deformed state and overlaps it in the axial direction. In this example, the tapered surface 43a is disposed in a position that overlaps in the axial direction with a portion of the outer peripheral surface of the side lip 35 in the elastically deformed state that is closer to the base end than the lip inflection point 42. A portion of the outer peripheral surface of the side lip 35 in the elastically deformed state that is closer to the tip end than the lip inflection point 42 overlaps in the axial direction with the tip end surface of the bank portion 36a.

[0121] In this example, the structure of the slinger large diameter cylindrical portion 25a of the slinger 22a that constitutes the combined seal ring 5a is different from the structure of the slinger large diameter cylindrical portion 25 of the first example.

[0122] The inner peripheral surface of slinger large-diameter cylindrical portion 25a is recessed radially outward at a position radially overlapping with the tip end (axially inner end) of bank portion 36a, and has drain groove 57 that opens to the axially outer end face of slinger large-diameter cylindrical portion 25a. Therefore, drain groove 57 is provided radially outward of the opening of storage space 45a formed between tapered surface 43a and the outer peripheral surface of side lip 35 in an elastically deformed state.

[0123] A plurality of drain grooves 57 are provided on the inner circumferential surface of slinger large-diameter cylindrical portion 25a. The number of drain grooves 57 provided on the inner circumferential surface of slinger large-diameter cylindrical portion 25a is not limited to this, but may be, for example, about 10 to 100. The plurality of drain grooves 57 are arranged at equal intervals in the circumferential direction on the inner circumferential surface of slinger large-diameter cylindrical portion 25a.

[0124] Drain groove 57 has a substantially rectangular cross-sectional shape with respect to an imaginary plane perpendicular to the central axis of slinger 22a. The radial depth of drain groove 57 is not limited to this, but may be, for example, 0.3 mm to 1.0 mm. In this example, the radial depth of drain groove 57 is constant along the axial direction, but may also vary depending on the axial position.

[0125] In this example, the inner peripheral surface of the slinger large-diameter cylindrical portion 25a is formed by a cylindrical cover portion 34a made of an elastic material. That is, the cylindrical cover portion 34a covers not only the outer peripheral surface and the axially outer end face of the large-diameter cylindrical core portion 31, but also the inner peripheral surface of the large-diameter cylindrical core portion 31. For this reason, the drain groove 57 is formed in the cylindrical cover portion 34a.

[0126] In this example, the centrifugal force acting when the slinger 22a rotates allows the muddy water guided to the inner peripheral surface of the slinger large-diameter cylindrical portion 25a to be drained through the drain groove 57. In addition, the drain groove 57 can turn the rotating water flow of the muddy water that reaches the sliding contact portion between the tip of the side lip 35 and the axially outer surface of the slinger annular portion 26 into a turbulent flow, thereby facilitating the drainage of the muddy water.

[0127] Other configurations and effects of the second example are the same as those of the first example.

[0128] [Example 3] A third example of the embodiment of the present disclosure will be described with reference to FIGS.

[0129] The combined seal ring 5b of this embodiment differs from the combined seal ring 5 of the first embodiment only in the structure of the bank portion 36b that constitutes the seal ring 23b.

[0130] The bank portion 36b has a tapered surface 43b having an inflection point 58 on its inner circumferential surface. Therefore, the inclination angles of the axially outer portion (base end portion) and the axially inner portion (tip end portion) of the tapered surface 43b, with the inflection point 58 sandwiched between them, are different from each other, relative to the central axis of the seal ring 23b. Specifically, the inclination angle of the portion of the tapered surface 43b that is axially outer than the inflection point 58 is greater than the inclination angle of the portion of the tapered surface 43b that is axially inner than the inflection point 58. By providing the inflection point 58, the axial length of the tapered surface 43b is greater than that of the structure of the first example.

[0131] The inflection point 58 is provided on the tapered surface 43b at a position corresponding to the lip inflection point 42 provided on the outer peripheral surface of the side lip 35 in an elastically deformed state.

[0132] In this example, the portion of tapered surface 43b that is axially outer than inflection point 58 is disposed approximately parallel to the portion of the outer circumferential surface of side lip 35 in the elastically deformed state that is closer to the base end than lip inflection point 42. Moreover, the portion of tapered surface 43b that is axially inner than inflection point 58 is disposed approximately parallel to the portion of the outer circumferential surface of side lip 35 in the elastically deformed state that is closer to the tip end than lip inflection point 42.

[0133] Therefore, in this example, the distance W (see FIG. 7) between the tapered surface 43b and the outer peripheral surface of the side lip 35 is substantially constant over the entire depth direction of the storage space 45b. 35 (See Figure 6) 35 ).

[0134] The outer peripheral surface of bank portion 36b is cylindrical. The outer diameter of bank portion 36b is slightly smaller than the inner diameter of slinger large-diameter cylindrical portion 25 (core large-diameter cylindrical portion 31). The outer peripheral surface of bank portion 36b closely faces the inner peripheral surface of slinger large-diameter cylindrical portion 25 over the entire circumference. As a result, a fourth labyrinth seal 59 extending in the axial direction is formed between the outer peripheral surface of bank portion 36b and the inner peripheral surface of slinger large-diameter cylindrical portion 25.

[0135] In this example, the gap W is substantially constant over the entire depth direction of the storage space 45b, thereby further reducing the volume of the storage space 45b. This further reduces the amount of muddy water temporarily stored in the storage space 45b, and further reduces the area of ​​the opposing portion 56 of the axially outer surface of the slinger annular portion 26 that faces the opening of the storage space 45b. This therefore improves the muddy water resistance of the combination seal ring 5.

[0136] Furthermore, because the bank portion 36b has a tapered surface 43b with an inflection point 58 on its inner circumferential surface, the thickness of the bank portion 36b near the tip is greater than that of the structure of the first example. This improves the radial rigidity of the bank portion 36b, and prevents the bank portion 36b from bending radially inward even when muddy water adheres to the outer circumferential surface of the bank portion 36b. Furthermore, because a fourth labyrinth seal 59 is formed between the outer circumferential surface of the bank portion 36b and the inner circumferential surface of the slinger large-diameter cylindrical portion 25, the amount of muddy water that reaches the sliding contact portion between the tip of the side lip 35 and the axially outer surface of the slinger annular portion 26 can be sufficiently reduced.

[0137] The other configurations and effects of the third example are the same as those of the first example.

[0138] The first to third examples described above can be implemented in any suitable combination as long as no contradiction occurs. [Explanation of symbols]

[0139] 1 Hub unit bearing 2 outer ring 3. Hub 4a, 4b rolling elements 5, 5a, 5b combination seal ring 6 Seal ring 7a, 7b Outer ring raceway 8 Stationary Flange 9 Support hole 10a, 10b Inner raceway 11 Rotating flange 12 Pilot Division 13 Spline hole 14 Mounting holes 15 studs 16 Inner Circle 17 Hub wheel 18 Small diameter stepped section 19 Step surface 20a, 20b retainer 21 Annular Space 22, 22a Slinger 23, 23a, 23b Seal rings 24 Slinger small diameter cylinder 25, 25a Slinger large diameter cylinder 26 Slinger ring part 28 Core 29 Encoder body 30 Core metal small diameter cylindrical part 31 Large diameter cylindrical core 32 Core metal ring part 33 Disc-shaped cover 34, 34a cylindrical covering portion 35 Side lip 36, 36a, 36b Embankment 37 Seal cylinder 38 Seal ring 39 First Labyrinth Seal 40 Second Labyrinth Seal 41 Grease Lip 42 Lip Inflection Point 43, 43a, 43b Tapered surface 44 Cylindrical Surfaces 45, 45a, 45b storage space 46 Back space 47 Opening side space 48 Third Labyrinth Seal 49 Main bank 50 Overhang 51 Seal core metal 52 Sealing material 53 Core tube part 54 Core flange 55 Seal base 56 Opposing part 57 Drain 58 Inflection Point 59 Fourth Labyrinth Seal 100 Hub unit bearing 101 outer ring 102 Hub 103 Annular Space 104 Combination Seal Ring 105 Slinger 106 Seal ring 107 Slinger small diameter cylinder 108 Slinger large diameter cylinder 109 Slinger circular ring 110 Seal cylinder 111 Seal ring part 112 First Labyrinth Seal 113 Side lip 114 Embankment 115 Flange 116 Second Labyrinth Seal 117 Storage space 118 Opposing part

Claims

1. A combination seal ring attached between an inner member and an outer member arranged coaxially with each other, and closing an opening of an annular space existing 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 substantially horizontal U-shaped cross section and includes a slinger small-diameter cylindrical portion fitted onto the inner member, a slinger large-diameter cylindrical portion disposed 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 to one axial end of the slinger large-diameter cylindrical portion, The seal ring has a conical cylindrical shape and a side lip whose tip is in sliding contact with the other axial side surface of the slinger ring portion, and a bank portion which has an annular shape and is disposed between the side lip and the slinger large-diameter cylindrical portion in the radial direction, The bank portion has an inner peripheral surface that is tapered and is disposed in a position that is approximately parallel to and overlaps in the axial direction with the outer peripheral surface of the side lip when the side lip is in an elastically deformed state with the tip end of the side lip in sliding contact with the side surface on the other axial side of the slinger ring portion. Combination seal ring.

2. 2. The combination seal ring according to claim 1, wherein a distance between the tapered surface and the outer peripheral surface of the side lip, which are arranged substantially parallel to each other, is substantially the same as a thickness of the side lip.

3. 2. A combination seal ring as described in claim 1, wherein the inner surface of the slinger large diameter cylindrical portion is recessed radially outward at a position radially overlapping with the end portion on one axial side of the bank portion, and has a drain groove that opens to the end face on the other axial side of the slinger large diameter cylindrical portion.

4. 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 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 3.

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