Hub unit bearing

Abstract

To provide a hub unit bearing capable of ensuring discharge performance of foreign matter entering a seal internal space between a large-diameter side rotating cylinder part and a seal lip, and capable of suppressing life deterioration of the seal lip.SOLUTION: A seal device 5 is composed of a slinger 23 and a seal ring 24. The slinger 23 has a rotating cylinder part 25, a rotating circular ring part 26, and a large-diameter side rotating cylinder portion 27, and the seal ring 24 has a core metal 37 and a seal material 38. The seal material 38 is provided with a plurality of fins 46 in a portion that axially faces an axial end surface of the large-diameter side rotating cylinder part 27. An inner peripheral surface of the large-diameter side rotating cylinder part 27 is inclined in the axial direction in a direction such that an inner diameter becomes larger as it approaches the fins 46.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a hub unit bearing. [Background technology]

[0002] A hub unit bearing supports the wheels of an automobile for rotation relative to a suspension system by means of an outer ring having a double row outer ring raceway on its inner circumferential surface, a hub having a double row inner ring raceway on its outer circumferential surface, and a number of rolling elements arranged to roll freely between the double row outer ring raceway and the double row inner ring raceway.

[0003] With respect to the hub unit bearing, the term "axially outer side" refers to the outer side in the width direction of the vehicle when the hub unit bearing is assembled to the vehicle, and the term "axially inner side" refers to the center side in the width direction of the vehicle when the hub unit bearing is assembled to the vehicle.

[0004] The hub unit bearing further includes a sealing device that closes the axial opening of the rolling element installation space that exists between the inner surface of the outer ring and the outer surface of the hub to prevent the intrusion of muddy water and the like from the outside.

[0005] As a sealing device for sealing the axial opening of the rolling element installation space, it is known to use a sealing device that includes a slinger that is fitted and fixed to the outside of the hub, and a seal ring having at least one seal lip with its tip in sliding contact with the surface of the slinger.

[0006] Japanese Patent Laid-Open Publication No. 2016-80145 (Patent Document 1) discloses a structure in which an opening on the axial inner side of a rolling element installation space is blocked by a seal device including a slinger and a seal ring. Fig. 8 shows a seal device 100 of a conventional structure described in Japanese Patent Laid-Open Publication No. 2016-80145.

[0007] The seal device 100 is composed of a slinger 101 and a seal ring 102.

[0008] The slinger 101 has a cross-sectional shape that is approximately C-shaped (horizontal U-shaped) and includes a rotating cylindrical portion 104 fitted and fixed to the outside of the hub 103, a rotating circular ring portion 105 extending radially outward from the axially inner end of the rotating cylindrical portion 104, and a large diameter rotating cylindrical portion 106 extending axially outward from the radially outer end of the rotating circular ring portion 105 and arranged radially overlapping the rotating cylindrical portion 104.

[0009] The slinger 101 is composed of a slinger body 107 made of a metallic material, and an encoder 108 made of magnetic rubber that is supported and fixed to the slinger body 107 .

[0010] The slinger body 107 has an approximately U-shaped cross-sectional shape and includes an inner diameter side cylindrical portion 109, a disc portion 110 extending radially outward from the axially inner end of the inner diameter side cylindrical portion 109, and an outer diameter side cylindrical portion 111 extending axially outward from the radially outer end of the disc portion 110.

[0011] The encoder 108 has an encoder disk portion 112 supported on the axially inner surface of the disk portion 110, and an encoder tube portion 113 covering the outer peripheral surface, inner peripheral surface, axially outer end face, and axially inner end face of the outer diameter side tube portion 111. The axially inner surface of the encoder disk portion 112 has S poles and N poles arranged alternately in the circumferential direction, and functions as a detection surface.

[0012] In the conventional sealing device 100, the rotating cylindrical portion 104 of the slinger 101 is composed only of the inner diameter side cylindrical portion 109 of the slinger body 107, the rotating circular ring portion 105 of the slinger 101 is composed of the disk portion 110 and the encoder disk portion 112 of the slinger body 107, and the large diameter side rotating cylindrical portion 106 of the slinger 101 is composed of the outer diameter side cylindrical portion 111 and the encoder cylindrical portion 113 of the slinger body 107.

[0013] The seal ring 102 includes a core metal 114 and a seal material 115 .

[0014] The core metal 114 comprises a fixed cylindrical portion 117 which is tightly fitted into the axially inner end of the outer ring 116, and a fixed circular ring portion 118 which extends radially inward from the axially outer end of the fixed cylindrical portion 117.

[0015] The seal material 115 has a seal base 119 and two seal lips 120a and 120b.

[0016] The seal base 119 has an annular covering portion 121 covering the inner surface of the fixed cylinder portion 117, and a circular ring-shaped covering portion 122 covering the axial inner surface, the radially inner end portion of the axial outer surface, and the inner surface of the fixed ring portion 118.

[0017] A labyrinth seal portion 123 extending in the axial direction is provided between the inner peripheral surface of the annular covering portion 121 and the outer peripheral surface of the encoder cylindrical portion 113. The radial width of the labyrinth seal portion 123 is constant along the axial direction.

[0018] Two seal lips 120a, 120b are provided on the radially inner side of the seal ring 102. The seal lip 120a arranged on the axially inner side is a side lip, and its tip portion is in sliding contact with the axially outer side surface of the disc portion 110 constituting the rotating ring portion 105 of the slinger 101. The seal lip 120b arranged on the axially outer side is a radial lip, and its tip portion is in sliding contact with the outer peripheral surface of the inner diameter side cylindrical portion 109 constituting the rotating cylindrical portion 104 of the slinger 101. [Prior art documents] [Patent documents]

[0019] [Patent Document 1] JP 2016-80145 A Summary of the Invention [Problem to be solved by the invention]

[0020] In recent years, there has been an increasing demand for lower torque in hub unit bearings. As a result, it has been considered to actively use labyrinth seals, which do not increase the seal torque, in the sealing devices incorporated in hub unit bearings, thereby reducing the number of seal lips and the tension force of the seal lips.

[0021] In the conventional seal device 100, a labyrinth seal portion 123 is provided between the inner surface of the annular covering portion 121 and the outer surface of the encoder tube portion 113, so that sealing performance is ensured by the two seal lips 120a, 120b.

[0022] Incidentally, in the conventional sealing device 100, the slinger 101 is press-fitted into the hub 103 by pressing the axially inner surface of the encoder disk portion 112 axially outward using a tool. For this reason, when the interference between the rotating cylinder portion 104 of the slinger 101 and the hub 103 is large, it is necessary to press the encoder disk portion 112 with a large force using the tool, and there is a possibility that the rotating ring portion 105 and the large diameter side rotating cylinder portion 106 will be deformed so as to be tilted in the direction of the arrow X in FIG. 8 (counterclockwise) relative to the rotating cylinder portion 104.

[0023] When the large diameter side rotating cylinder portion 106 is tilted in the direction of the arrow X, the inner peripheral surface of the large diameter side rotating cylinder portion 106 is inclined in the axial direction in a direction in which the inner diameter becomes smaller from the base end side to the tip end side of the large diameter side rotating cylinder portion 106. For this reason, foreign matter such as muddy water is likely to accumulate in the seal internal space (lip front side space) 124 that exists between the large diameter side rotating cylinder portion 106 and the seal lip 120a in the seal device 100. This may cause problems such as the seal lip 120a being wet for a long time, which may shorten the life of the seal lip 120a.

[0024] In addition, the slinger body having an approximately U-shaped cross-sectional shape is generally manufactured by a manufacturing method in which a steel strip having rust-resistant properties is punched to form a circular plate-shaped blank, then the blank is burred to form an inner diameter side cylindrical portion and an outer diameter side cylindrical portion from the radial outer portion and radial inner portion of the blank.

[0025] For this reason, even in the case of the seal device 100 having a conventional structure, spring back or spring go (spring in) may occur in the inner diameter side cylinder portion 109 and the outer diameter side cylinder portion 111 that constitute the slinger body 107. If spring go occurs in the inner diameter side cylinder portion 109 and / or the outer diameter side cylinder portion 111, the large diameter side rotating cylinder portion 106 will tilt in the direction of the arrow X, as in the case when the slinger 101 is pressed in as described above. This may reduce the ability to discharge foreign matter from the seal internal space 124, and the time that the seal lip 120a remains wet may increase, resulting in a shortened lifespan of the seal lip 120a.

[0026] The present invention has been made to solve the above-mentioned problems, and has an object to provide a hub unit bearing that can ensure the discharge of foreign matter that has entered the internal space of the seal between the large diameter side rotating cylinder portion and the seal lip, and can suppress a decrease in the life of the seal lip. [Means for solving the problem]

[0027] A hub unit bearing according to one aspect of the present invention includes an outer ring, a hub, a plurality of rolling elements, and a seal device. The outer ring has a double row outer ring raceway on its inner circumferential surface. The hub has a double row inner ring raceway on its outer circumferential surface. The plurality of rolling elements are disposed so as to roll freely between the double row outer ring raceways and the double row inner ring raceways. The seal device has a slinger and a seal ring, and closes an axial opening of a rolling element installation space that exists between the inner peripheral surface of the outer ring and the outer peripheral surface of the hub. The slinger has an approximately C-shaped cross-sectional shape and includes a rotating cylindrical portion that is fitted onto the hub, a rotating annular portion that extends radially outward from the axial end of the rotating cylindrical portion, and a large diameter rotating cylindrical portion that is arranged radially outside the rotating cylindrical portion so as to overlap radially with the rotating cylindrical portion. The seal ring includes a core metal and a seal material. The core wire has a fixed cylindrical portion that is fitted and fixed to the outer ring so as to overlap radially with the large diameter side rotating cylindrical portion, and a fixed circular ring portion that extends radially inward from the axial end of the fixed cylindrical portion. The sealing material has at least one seal lip with its tip in sliding contact with the surface of the slinger, an annular covering portion covering the inner surface of the fixed cylinder portion, a circular ring-shaped covering portion covering the axial side surface of the fixed ring portion, and a plurality of fins provided in a portion axially opposite the axial end face of the large diameter side rotating cylinder portion. The inner circumferential surface of the large diameter side rotating cylinder portion is inclined in the axial direction in a direction such that the inner diameter becomes larger as it approaches the fins.

[0028] In the hub unit bearing according to one aspect of the present invention, the inner circumferential surface of the annular covering portion can be inclined in the axial direction in a direction such that the inner diameter becomes smaller the closer it is to the fin.

[0029] In the hub unit bearing according to one aspect of the present invention, the outer circumferential surface of the large diameter side rotating cylindrical portion can be inclined in the axial direction in a direction such that the outer diameter becomes smaller the closer it is to the fin.

[0030] In a hub unit bearing according to one aspect of the present invention, the fixed ring portion may be provided with an inclined plate portion in a radially intermediate portion thereof that is inclined in a direction approaching the rotating ring portion in the axial direction as it moves radially inward.

[0031] In a hub unit bearing according to one embodiment of the present invention, the sealing device can be provided with a first labyrinth seal portion between an inner surface of the annular covering portion and an outer surface of the large diameter side rotating cylinder portion, the radial width of which increases axially toward the fin.

[0032] In a hub unit bearing according to one embodiment of the present invention, the sealing device can be provided with a second labyrinth seal portion between the outer peripheral surface of a portion of the annular covering portion that covers the outer peripheral surface of the inclined plate portion and the inner peripheral surface of the large diameter side rotating cylinder portion, the radial width of which decreases as it approaches the fin in the axial direction (from the base end side to the tip end side of the large diameter side rotating cylinder portion). In the hub unit bearing according to one aspect of the present invention, the fins can also be provided on a portion of the annular covering portion that covers the outer circumferential surface of the inclined plate portion.

[0033] In a hub unit bearing according to one aspect of the present invention, the slinger is composed of a slinger body made of a metallic material and an encoder supported by the slinger body, and the inner surface of the large diameter side rotating cylinder portion can be formed by a part of the encoder. In this case, the outer circumferential surface of the large diameter side rotating cylindrical portion can also be formed by a part of the encoder. Conversely, the inner peripheral surface of the large diameter rotating cylinder portion may be formed by a part of the slinger body, and the outer peripheral surface of the large diameter rotating cylinder portion may be formed by a part of the encoder. Furthermore, in the hub unit bearing according to one aspect of the present invention, the slinger can be constructed solely from a slinger body made of a metallic material. Effect of the Invention

[0034] According to the hub unit bearing of one aspect of the present invention, it is possible to ensure the discharge of foreign matter that has entered the internal seal space between the large diameter side rotating cylindrical portion and the seal lip, and to suppress a decrease in the life of the seal lip. [Brief description of the drawings]

[0035] [Figure 1] FIG. 1 is a cross-sectional view showing a hub unit bearing according to a first example of the embodiment. [Diagram 2] FIG. 2 is an enlarged view of part A in FIG. [Diagram 3]FIG. 3 is a schematic diagram of a seal ring constituting a seal device taken out of a hub unit bearing according to a first example of the embodiment, and a circumferential portion of a portion around a fin, viewed from the axially inner side. [Figure 4] FIG. 4 is a diagram showing a second embodiment of the present invention, and corresponds to FIG. [Diagram 5] FIG. 5 is a diagram showing a third example of the embodiment, and corresponds to FIG. [Figure 6] FIG. 6 is a diagram showing a fourth example of the embodiment, and corresponds to FIG. [Figure 7] FIG. 7 is a diagram showing a fifth example of the embodiment, and corresponds to FIG. [Figure 8] FIG. 8 is a cross-sectional view showing a sealing device of a conventional structure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0036] [First Example of Implementation] A first example of the embodiment will be described with reference to FIGS. 1 to 3. FIG.

[0037] The hub unit bearing of the present invention can be applied to hub unit bearings of various structures, but in this example, a case where it is applied to a hub unit bearing for a driving wheel will be described.

[0038] The hub unit bearing 1 of this example includes an outer ring 2, a hub 3, a plurality of rolling elements 4a, 4b, and a pair of sealing devices 5, 6.

[0039] In the following description of the hub unit bearing 1, the left side of Figs. 1 and 2, which is located on the outer side in the width direction of the vehicle when the hub unit bearing 1 is assembled to the vehicle, is referred to as the axial outer side, and the right side of Figs. 1 and 2, which is located on the central side in the width direction of the vehicle when the hub unit bearing 1 is assembled to the vehicle, is referred to as the axial inner side.

[0040] 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 outer ring raceways 7a, 7b on its inner circumferential surface. Furthermore, 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 in the axial direction at multiple circumferential positions at the radially intermediate portion.

[0041] In this example, the support hole 9 is configured with a screw hole. 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.

[0042] 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 10a, 10b on its outer peripheral surface. The hub 3 also has a rotating flange 11 protruding radially outward at a portion that protrudes axially outward beyond the outer ring 2. The hub 3 also has a cylindrical pilot portion 12 at its axially outer end. The hub 3 also has a spline hole 13 in its radial center that penetrates the hub 3 in the axial direction.

[0043] The rotating flange 11 has mounting holes 14 penetrating in the axial direction at multiple circumferential positions in a radially intermediate portion. A stud 15 for connecting and fixing a braking rotor such as a disk or drum and a wheel that constitutes a wheel to the rotating flange 11 is press-fitted into each of the mounting holes 14 with serrations. That is, in this example, the mounting holes 14 are cylindrical holes.

[0044] 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 of them and inserting a stud 15 into through holes provided at multiple locations in the circumferential direction of each of them in the radial middle portion, and then screwing a hub nut onto the tip of the stud 15.

[0045] The mounting holes of the rotating flange may be threaded holes. In this case, the braking rotor and the wheel are fixed to the rotating flange by threading a hub bolt, which passes through a through hole in the braking rotor and a through hole in the wheel, into the mounting hole from the outside in the axial direction.

[0046] The tip of a drive shaft that is rotated and driven by an engine or electric motor as a drive source is splined into the spline hole 13. When the vehicle is traveling, the drive shaft rotates the hub 3, thereby rotating the wheels and braking rotors that are joined and fixed to the rotating flange 11 of the hub 3. In other words, the hub unit bearing 1 of this example has a structure for use with a driving wheel.

[0047] However, the hub unit bearing of the present invention can also be applied to a hub unit bearing for a driven wheel in which the hub has a solid structure that is not provided with a spline hole penetrating in the axial direction.

[0048] In this example, the hub 3 is formed by combining an inner ring 16 and a hub ring 17 .

[0049] The inner ring 16 is made of a hard metal such as bearing steel, etc. The inner ring 16 has an inner ring raceway 10b on the outer circumferential surface thereof, the inner ring raceway 10b being located on the axially inner side.

[0050] 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.

[0051] 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. Furthermore, the hub ring 17 has a step surface 19 facing axially inward at the axially outer end of the small diameter step 18, and has a crimped portion 20 bent radially outward from the axially inner end of the small diameter step 18.

[0052] The inner ring 16 is fitted onto the small diameter step 18 of the hub ring 17, and is sandwiched from both axial sides between a step surface 19 and a crimped portion 20 of the hub ring 17. In this way, the inner ring 16 and the hub ring 17 are joined to form the hub 3, and an appropriate preload is applied to the rolling elements 4a, 4b. Note that it is also possible to configure the hub ring so that a nut is screwed onto the axially inner end of the inner ring that protrudes from the axially inner end of the inner ring, and the inner ring is sandwiched from both axial sides between the step surface of the hub ring and the nut.

[0053] The rolling elements 4a, 4b are made of an iron alloy such as bearing steel or ceramics, and are arranged between the double row outer ring raceways 7a, 7b and the double row inner ring raceways 10a, 10b in a rollable manner while being held by cages 21a, 21b. As a result, the hub 3 is supported on the radial inside of the outer ring 2 in a rotatable manner.

[0054] The hub unit bearing 1 of this example has an equal PCD type structure in which the pitch circle diameter of the rolling elements 4a in the axially outer row is equal to the pitch circle diameter of the rolling elements 4b in the axially inner row. However, the present invention can also be applied to a different PCD type hub unit bearing in which the pitch circle diameter of the rolling elements in the axially outer row is larger or smaller than the pitch circle diameter of the rolling elements in the axially inner row. Also, although balls are used as the rolling elements 4a and 4b in the hub unit bearing 1 of this example, tapered rollers can be used instead of balls.

[0055] The pair of sealing devices 5, 6 are present between the inner peripheral surface of the outer ring 2 and the outer peripheral surface of the hub 3, and close the openings on both axial sides of the rolling element installation space 22 in which the rolling elements 4a, 4b are arranged. This prevents leakage of grease sealed in the rolling element installation space 22, and prevents foreign matter such as muddy water from entering the rolling element installation space 22.

[0056] The seal device 5 corresponds to the seal device recited in the claims, and closes the opening on the axially inner side of the rolling element installation space 22. In contrast, the seal device 6 closes the opening on the axially outer side of the rolling element installation space 22. In this example, the present invention is applied to a seal device that closes the opening on the axially inner side of the rolling element installation space, but the present invention can also be applied to a seal device that closes the opening on the axially outer side of the rolling element installation space.

[0057] The seal device 5 is a combined seal ring having a slinger 23 and a seal ring 24. The slinger 23 and the seal ring 24 are arranged coaxially and overlapping with each other in the axial direction. In the portion where the slinger 23 and the seal ring 24 overlap in the axial direction, the slinger 23 is arranged on the side farther from the rolling element installation space 22, and the seal ring 24 is arranged on the side closer to the rolling element installation space 22.

[0058] The slinger 23 is configured in an annular shape as a whole, and has a substantially U-shaped cross section (horizontal U-shape). The slinger 23 has a rotating tubular portion 25 fitted and fixed to the inner ring 16 constituting the hub 3, a rotating circular ring portion 26 extending radially outward from an axially inner end of the rotating tubular portion 25, and a large diameter rotating tubular portion 27 extending axially outward from a radially outer end of the rotating circular ring portion 26 and disposed overlapping the rotating tubular portion 25 in the radial direction.

[0059] The slinger 23 is composed of a slinger body 28 made of a metallic material, and an encoder 29 made of magnetic rubber that is supported and fixed to the slinger body 28.

[0060] The slinger body 28 is made of a magnetic and rust-resistant metal material, such as SUS430 stainless steel plate, and has a generally U-shaped cross section. The slinger body 28 is made by punching a steel strip to form a disk-shaped blank, and then burring the blank.

[0061] The slinger body 28 has a cylindrical inner diameter side tube portion 30, a disc portion 31 extending radially outward from the axially inner end of the inner diameter side tube portion 30, and a cylindrical outer diameter side tube portion 32 extending axially outward from the radially outer end of the disc portion 31.

[0062] The inner diameter side cylinder portion 30 is fixed to the axially inner end of the outer circumferential surface of the inner ring 16 by press-fitting. The disk portion 31 is bent at an approximately right angle from the axially inner end of the inner diameter side cylinder portion 30 toward the radially outer side. The outer diameter side cylinder portion 32 is disposed approximately coaxially with the inner diameter side cylinder portion 30. The axial dimension of the outer diameter side cylinder portion 32 is shorter than the axial dimension of the inner diameter side cylinder portion 30. The axial dimension of the outer diameter side cylinder portion 32 is approximately 1 / 10 to 1 / 2 of the axial dimension of the inner diameter side cylinder portion 30, and is approximately 1 / 5 in the illustrated example.

[0063] The encoder 29 is a rubber magnet made of rubber with ferrite powder mixed in, formed into a circular ring shape, and is bonded to the slinger body 28 by vulcanization.

[0064] The encoder 29 has an encoder disk portion 33 supported on the axially inner surface of the disk portion 31, and an encoder tube portion 34 covering the outer peripheral surface, inner peripheral surface, axially outer end face, and axially inner end face of the outer diameter side tube portion 32. The radially outer end of the encoder disk portion 33 and the portion of the encoder tube portion 34 covering the axially inner end face of the outer diameter side tube portion 32 are connected in the radial direction.

[0065] The axially inner surface of the encoder disk portion 33 has S poles and N poles arranged alternately in the circumferential direction, and functions as a detection surface. A detection portion of a rotation speed sensor (not shown) faces the axially inner surface of the encoder disk portion 33. This detects the rotation speed of the wheels and is used to control vehicle control devices such as the ABS.

[0066] In this example of the sealing device 5, the rotating cylinder portion 25 of the slinger 23 is composed only of the inner diameter side cylinder portion 30 of the slinger body 28, the rotating circular ring portion 26 of the slinger 23 is composed of the disk portion 31 and the encoder disk portion 33 of the slinger body 28, and the large diameter side rotating cylinder portion 27 of the slinger 23 is composed of the outer diameter side cylinder portion 32 and the encoder cylinder portion 34 of the slinger body 28.

[0067] The encoder disk portion 33 has a lip portion 35 at its radially inner end. The lip portion 35 contacts the outer peripheral surface of the axially inner end of the inner ring 16 over the entire circumference. Note that Fig. 2 shows the shape of the lip portion 35 in a free state. The axially inner surface of the encoder disk portion 33, excluding the lip portion 35, is formed by a plane (annular surface) perpendicular to the central axis of the slinger 23.

[0068] The axially inner end face of the encoder tube portion 34 is formed by a plane perpendicular to the central axis of the slinger 23, and is located on the same plane as the axially inner side surface of the encoder disk portion 33. In addition, the axially outer end face of the encoder tube portion 34 is formed by a plane perpendicular to the central axis of the slinger 23.

[0069] The outer peripheral surface of the encoder tube portion 34 constitutes the outer peripheral surface of the large diameter rotating tube portion 27 of the slinger 23. The outer peripheral surface of the encoder tube portion 34 is configured as a tapered surface that is inclined in a direction in which the outer diameter becomes smaller as it goes outward in the axial direction (approaching fins 46 described later in relation to the axial direction). The inclination angle α (see FIG. 2) of the outer peripheral surface of the encoder tube portion 34 with respect to the central axis of the slinger 23 is not particularly limited, but can be set in the range of 10 degrees to 20 degrees (15 degrees in the illustrated example), for example.

[0070] The inner peripheral surface of the encoder tube portion 34 constitutes the inner peripheral surface of the large diameter rotating tube portion 27 of the slinger 23. Therefore, in this example, the inner peripheral surface of the large diameter rotating tube portion 27 is formed by a part of the encoder 29. The inner peripheral surface of the encoder tube portion 34 is formed by a tapered surface that is inclined in a direction in which the inner diameter becomes larger as it goes outward in the axial direction (approaching fins 46 described later in relation to the axial direction). Therefore, the inner peripheral surface of the encoder tube portion 34 is inclined in the opposite direction to the outer peripheral surface of the encoder tube portion 34.

[0071] The inclination angle of the inner peripheral surface of the encoder tubular portion 34 is not particularly limited. However, even if the large diameter side rotating tubular portion 27 is inclined relative to the rotating tubular portion 25 in the direction of the arrow X in Fig. 8 (counterclockwise direction) when the slinger 23 is pressed in, or if the large diameter side rotating tubular portion 27 is inclined relative to the rotating tubular portion 25 in the direction of the arrow X due to spring go that occurs during the manufacture of the slinger main body 28 that constitutes the slinger 23, the inclination angle of the inner peripheral surface of the encoder tubular portion 34 relative to the central axis of the slinger 23 can be set in the range of, for example, 10 degrees to 20 degrees (15 degrees in the illustrated example) so that the inner peripheral surface of the encoder tubular portion 34 becomes a tapered surface inclined in a direction in which the inner diameter increases toward the axially outward side.

[0072] The encoder cylindrical portion 34 has a ridge portion 36, which is a sharp corner (edge), at a portion where the outer circumferential surface and the axially inner end face intersect.

[0073] The seal ring 24 includes a core metal 37 and a seal material 38 .

[0074] The core metal 37 is formed by bending a metal plate such as a soft steel plate into a generally L-shaped cross section, and is configured in an annular shape as a whole.

[0075] The core metal 37 includes a fixed cylinder portion 39 having a cylindrical shape that is tightly fitted into the axially inner end portion of the outer ring 2, and a fixed ring portion 40 that extends radially inward from the axially outer end portion of the fixed cylinder portion 39. The fixed cylinder portion 39 is disposed so as to overlap with the large diameter side rotating cylinder portion 27 of the slinger 23 in the radial direction.

[0076] The fixed ring portion 40 in this example has a substantially crank-shaped cross section and has a conical cylindrical inclined plate portion 42 in the radial middle portion. Specifically, the fixed ring portion 40 has an outer flat plate portion 41 bent at a substantially right angle from the axially outer end portion of the fixed cylinder portion 39 toward the radially inner side, a conical cylindrical inclined plate portion 42 inclined in the axial direction toward the rotating ring portion 26 (axially inward) as it moves radially inward from the radially inner end portion of the outer flat plate portion 41, and an inner flat plate portion 43 bent from the axially inner end portion of the inclined plate portion 42 toward the radially inner side and disposed substantially parallel to the outer flat plate portion 41.

[0077] The seal material 38 is made of an elastic material such as an elastomer like rubber, and has a seal base 44, two seal lips 45a, 45b, and a plurality of fins 46.

[0078] The seal base 44 covers the surface of the core metal 37. The seal base 44 has an annular covering portion 47 and a circular ring-shaped covering portion 48.

[0079] The annular covering portion 47 covers the surface of the fixed cylinder portion 39 that constitutes the core bar 37. In this example, the annular covering portion 47 covers the inner circumferential surface of the fixed cylinder portion 39, the axially inner end portion of the outer circumferential surface, and the axially inner end face.

[0080] The inner peripheral surface of the annular covering portion 47 is configured as a tapered surface that is inclined in a direction in which the inner diameter becomes smaller as it goes outward in the axial direction (approaching the fins 46 in the axial direction). Therefore, the inclination direction of the inner peripheral surface of the annular covering portion 47 with respect to the central axis of the seal ring 24 is the same as the inclination direction of the outer peripheral surface of the encoder cylindrical portion 34 with respect to the central axis of the slinger 23. The inclination angle β (see FIG. 2) of the inner peripheral surface of the annular covering portion 47 with respect to the central axis of the seal ring 24 is not particularly limited, but can be set in the range of 3 degrees to 15 degrees (5 degrees in the illustrated example), for example.

[0081] In this example, the inclination angle β of the inner circumferential surface of the annular covering portion 47 is smaller than the inclination angle α of the outer circumferential surface of the encoder cylindrical portion 34 (β<α).

[0082] The sealing device 5 includes a first labyrinth seal portion 49 between the inner peripheral surface of the annular covering portion 47 and the outer peripheral surface of the encoder cylindrical portion 34. In this example, since the inclination angle β of the inner peripheral surface of the annular covering portion 47 is smaller than the inclination angle α of the outer peripheral surface of the encoder cylindrical portion 34, the radial width of the first labyrinth seal portion 49 increases toward the outside in the axial direction (closer to the fins 46 in the axial direction).

[0083] The annular covering portion 48 covers the surface of the fixed annular portion 40 constituting the core metal 37. The annular covering portion 48 in this example covers the axial inner side surface, the radial inner end of the axial outer side surface, and the inner circumferential surface of the fixed annular portion 40. Specifically, the annular covering portion 48 covers the axial inner side surface of the outer flat plate portion 41 and the outer circumferential surface (axial inner side surface) of the inclined plate portion 42, and covers the axial inner side surface, inner circumferential surface, and the radial inner end of the axial outer side surface of the inner flat plate portion 43. The axial inner side surface of the portion of the annular covering portion 48 that covers the axial inner side surface of the inner flat plate portion 43 is located axially outward of the axial outer end surface of the large diameter side rotating cylinder portion 27.

[0084] The multiple fins 46 are provided at a portion that faces in the axial direction the axially outer end face of the large diameter side rotating cylindrical portion 27. The number of fins 46 is not particularly limited, but the seal ring 24 may be provided with, for example, about 30 to 60 fins.

[0085] The fins 46 have a trapezoidal shape when viewed in the circumferential direction, and are configured as thin plates. The fins 46 each extend in the radial direction (radial direction) and are arranged at equal intervals in the circumferential direction. The multiple fins 46 are configured in a pleated shape when the seal ring 24 is viewed from the inside in the axial direction. In other words, there is a gap between the fins 46 adjacent to each other in the circumferential direction.

[0086] The radially outer end of the fin 46 is connected to the axially outer portion of the inner peripheral surface of the annular covering portion 47. The radially inner end of the fin 46 is connected to the outer peripheral surface of the portion of the annular covering portion 48 that covers the outer peripheral surface of the inclined plate portion 42. The axially outer end of the fin 46 is connected to the axially inner surface of the portion of the annular covering portion 48 that covers the axially inner surface of the outer flat plate portion 41.

[0087] An axially inner end face of the fin 46 is configured in a plane perpendicular to the central axis of the seal ring 24. Moreover, the axially inner end face of the fin 46 is located on the same plane as the axially inner surface of a portion of the annular covering portion 48 that covers the axially inner surface of the inner flat plate portion 43. In this example, a radially intermediate portion of the axially inner end face of the fin 46 closely faces the axially outer end face of the large diameter side rotating cylindrical portion 27 (encoder cylindrical portion 34) in the axial direction.

[0088] Two seal lips 45a, 45b are provided on the radially inner side of the seal ring 24. The seal lip 45a arranged on the axially inner side is a side lip, and its tip portion is in sliding contact with the axially outer side surface of the disc portion 31 constituting the rotating ring portion 26 of the slinger 23. The seal lip 45b arranged on the axially outer side is a radial lip, and its tip portion is in sliding contact with the outer circumferential surface of the inner diameter side cylindrical portion 30 constituting the rotating cylindrical portion 25 of the slinger 23. Note that FIG. 2 shows the shapes of the seal lips 45a, 45b in a free state.

[0089] The seal device 5 of this example prevents foreign matter such as muddy water from entering the rolling element installation space 22 from the external space and prevents grease sealed in the rolling element installation space 22 from leaking to the external space through the gap between the slinger 23 and the seal ring 24. Specifically, it prevents foreign matter from entering the rolling element installation space 22 from the external space and prevents grease from leaking from the rolling element installation space 22 to the external space through an annular seal internal space (lip front space) 50 existing between the large diameter side rotating cylinder portion 27 and the seal lip 45a and an annular inter-lip space 51 existing between the two seal lips 45a, 45b.

[0090] According to the hub unit bearing 1 of this embodiment, it is possible to ensure that foreign matter that has entered the seal internal space 50 can be discharged, and it is possible to suppress a decrease in the life span of the seal lip 45a.

[0091] That is, in this example, the inner peripheral surface of the encoder tubular portion 34 constituting the inner peripheral surface of the large diameter side rotating tubular portion 27 is configured as a tapered surface inclined in the direction in which the inner diameter becomes larger in the axial direction as it approaches the fin 46. Therefore, by utilizing the inclination of the inner peripheral surface of the encoder tubular portion 34, foreign matter such as muddy water that has entered the seal internal space 50 can be guided to the gap between the axially outer end face of the encoder tubular portion 34 and the seal ring 24 (the fin 46 and the annular covering portion 48), which is the outlet of the seal internal space 50. Therefore, it is possible to ensure the discharge of foreign matter that has entered the seal internal space 50. As a result, it is possible to suppress a decrease in the life of the seal lip 45a.

[0092] In addition, the seal ring 24 of this example has a plurality of fins 46 at a portion facing the axial outer end face of the large diameter side rotating cylinder portion 27. Therefore, the rotational momentum of the muddy water that has entered the first labyrinth seal portion 49, which becomes a rotating water flow with the rotation of the slinger 23, can be weakened by the plurality of fins 46. Specifically, the rotational momentum of the muddy water can be weakened (stopped) by allowing the muddy water to enter the gap between the fins 46 adjacent in the circumferential direction. A laminar rotating water flow makes it easy for the seal lip 45a to turn over due to collision, and also makes it easy for the seal lip 45a to turn over hydrodynamically. In this example, the rotational momentum of the muddy water can be weakened by the plurality of fins 46, so that the occurrence of the turning over of the seal lip 45a can be suppressed. Therefore, the tension of the seal lip 45a can be reduced, the torque can be reduced, and wear can be reduced, thereby suppressing a decrease in the lifespan.

[0093] Also, in this example, the inner circumferential surface of the annular covering portion 47 is configured as a tapered surface that is inclined in the axial direction so that the inner diameter increases the further away from the fins 46. Therefore, the inclination of the inner circumferential surface of the annular covering portion 47 can be used to discharge foreign matter such as muddy water discharged from the gap between the axially outer end face of the encoder cylindrical portion 34 and the seal ring 24 (the fins 46 and the annular covering portion 48) into the external space.

[0094] In addition, in this example, the inclination angle β of the inner peripheral surface of the annular covering portion 47 is made smaller than the inclination angle α of the outer peripheral surface of the encoder tube portion 34, so that the radial width of the first labyrinth seal portion 49 is made larger in the axial direction toward the fins 46. Therefore, the force of foreign matter that has entered the first labyrinth seal portion 49 toward the axially outward direction can be weakened toward the seal internal space 50 (fins 46). Therefore, foreign matter such as muddy water can be prevented from entering the seal internal space 50.

[0095] Furthermore, in this example, a ridge portion 36 is provided at the portion of the encoder tube portion 34 where the outer peripheral surface and the axially inner end face intersect, so that the ridge portion 36 can be used to efficiently scatter (shake off) moisture such as muddy water adhering to the axially inner surface of the rotating circular ring portion 26 of the slinger 23 into the external space.

[0096] In the above-described embodiment, the radial width of the first labyrinth seal portion 49 is increased toward the fins 46, thereby weakening the axial momentum of foreign matter that has entered the first labyrinth seal portion 49, and the multiple fins 46 can weaken the rotational momentum of the foreign matter. Therefore, even with a small number of seal lips 45a, 45b, sufficient sealing performance can be ensured without excessively increasing the tension of the seal lips 45a, 45b. As a result, the sealing performance of the seal device 5 can be ensured without increasing the seal torque, and the torque of the hub unit bearing 1 can be reduced.

[0097] [Second Example of the Implementation Form] A second embodiment will be described with reference to FIG.

[0098] This example is a modification of the first embodiment, and the structure of the sealing device 5a is changed from the structure of the first embodiment.

[0099] In this example, the axial dimension of the large diameter side rotating cylinder portion 27a constituting the slinger 23 is longer than that of the structure of the first example of the embodiment. Specifically, the axial dimensions of the outer diameter side cylinder portion 32a and the encoder cylinder portion 34a constituting the large diameter side rotating cylinder portion 27a are longer than that of the structure of the first example of the embodiment. In the illustrated example, the axial dimension of the outer diameter side cylinder portion 32a is approximately 1 / 2 the axial dimension of the inner diameter side cylinder portion 30. In addition, the axially outer end face of the large diameter side rotating cylinder portion 27a is positioned axially outward from the axially inner surface of the inner flat plate portion 43 constituting the core metal 37 of the seal ring 24.

[0100] This makes the axial length of the first labyrinth seal portion 49a provided between the inner peripheral surface of the annular covering portion 47 and the outer peripheral surface of the encoder cylindrical portion 34a longer than in the structure of the first example of the embodiment.

[0101] In this example, the axial dimension of the large diameter side rotating cylinder portion 27a is made longer than that of the structure of the first example of the embodiment, and accordingly the axial width of the fin 46a is made smaller. The axially inner end face of the fin 46a is located axially outward from the axially inner surface of the portion of the annular covering portion 48 that covers the axially inner surface of the inner flat plate portion 43. The axially inner end face of the fin 46a is located in the axially middle portion of the portion of the annular covering portion 48 that covers the outer circumferential surface of the inclined plate portion 42.

[0102] The seal device 5a includes a second labyrinth seal portion 52 between the outer circumferential surface of the portion of the annular covering portion 48 that covers the outer circumferential surface of the inclined plate portion 42 and the inner circumferential surface of the encoder cylinder portion 34.

[0103] In this example, the inclination angle γ of the outer circumferential surface of the portion of the annular covering portion 48 that covers the outer circumferential surface of the inclined plate portion 42 with respect to the central axis of the seal ring 24 is larger than the inclination angle δ of the inner circumferential surface of the encoder cylindrical portion 34a with respect to the central axis of the slinger 23 (γ>δ). Therefore, the radial width of the second labyrinth seal portion 52 becomes smaller in the axial direction as it approaches the fin 46a.

[0104] In the present embodiment described above, the radial width of the second labyrinth seal portion 52 becomes smaller in the axial direction toward the fin 46a, so that the force of foreign matter discharged from the seal internal space 50 through the second labyrinth seal portion 52 can be made stronger toward the fin 46a. This can further improve the dischargeability of foreign matter. In addition, the axial length (total length) of the first labyrinth seal portion 49a can be made longer, so that the intrusion of foreign matter into the seal internal space 50 can be effectively prevented. The other configurations and effects are the same as those of the first embodiment.

[0105] [Third Example of the Implementation Form] A third embodiment will be described with reference to FIG.

[0106] This example is a modification of the second example of the embodiment, and the radial width of the second labyrinth seal portion 52a constituting the seal device 5b is changed from the structure of the second example of the embodiment.

[0107] In this example, the radial width of the outer flat plate portion 41a constituting the core bar 37 and the inclination angle of the inclined plate portion 42a with respect to the central axis of the seal ring 24 are each made smaller than those in the structure of the second example of the embodiment. As a result, the outer diameter of the portion of the annular covering portion 48 that covers the outer circumferential surface of the inclined plate portion 42a is made larger than those in the structure of the second example of the embodiment.

[0108] As a result, the radial width of the second labyrinth seal portion 52a provided between the outer peripheral surface of the portion of the circular ring-shaped covering portion 48 that covers the outer peripheral surface of the inclined plate portion 42a and the inner peripheral surface of the encoder tube portion 34a is made smaller than the structure of the second example of the embodiment at any axial position of the second labyrinth seal portion 52a.

[0109] In the present embodiment as described above, foreign matter such as muddy water can be more effectively prevented from entering the seal internal space 50 through the second labyrinth seal portion 52a. In addition, the force of foreign matter expelled from the second labyrinth seal portion 52a can be further increased, so that the expulsion performance of foreign matter can be further improved. The other configurations and effects are the same as those of the first and second embodiments.

[0110] [Fourth Example of the Implementation Form] A fourth example of the embodiment will be described with reference to FIG.

[0111] This example is a modification of the second example of the embodiment, and the shape of the fins 46b constituting the seal device 5c is changed from the structure of the second example of the embodiment.

[0112] In this example, the fin 46b is configured as a thin plate having an approximately L-shape when viewed in the circumferential direction, and the fin 46b extends to the axially inner end of the portion of the circular ring-shaped covering portion 48 that covers the outer peripheral surface of the inclined plate portion 42a.

[0113] In the present embodiment as described above, since the overall length of the fins 46b can be increased, the momentum of rotation of the foreign matter passing through the second labyrinth seal portion 52 can be effectively weakened. The other configurations and effects are the same as those of the first and second embodiments.

[0114] [Fifth Example of the Implementation Form] A fifth example of the embodiment will be described with reference to FIG.

[0115] In the sealing device 5d of this example, the slinger 23a is composed only of a slinger body 28a. In other words, the slinger 23a of this example does not include the encoder that the slingers of the first to fourth examples of the embodiment include.

[0116] The slinger 23a has a cross-sectional shape that is approximately C-shaped (horizontal U-shaped) and includes a rotating cylinder portion 25, a rotating circular ring portion 26a extending radially outward from the axially inner end of the rotating cylinder portion 25, and a large diameter side rotating cylinder portion 27a extending axially outward from the radially outer end of the rotating circular ring portion 26a and arranged radially overlapping the rotating cylinder portion 25.

[0117] The slinger body 28a of this example has an inner diameter side cylindrical portion 30, a disk portion 31, an outer diameter side cylindrical portion 32a, and a folded portion 53.

[0118] The folded-back portion 53 is disposed between the radially outer end of the disc portion 31 and the axially inner end of the outer diameter side cylinder portion 32a, and connects the disc portion 31 and the outer diameter side cylinder portion 32a. The folded-back portion 53 is folded back from the radially outer end of the disc portion 31 toward the axially outer side and radially inner side, so as to have a substantially U-shaped cross section.

[0119] The outer diameter side cylinder portion 32a is configured to have a conical cylindrical shape in the axial direction. The outer diameter side cylinder portion 32a is inclined in the axial direction in a direction in which the outer diameter and inner diameter become larger as it approaches the fin 46. However, the outer diameter (maximum outer diameter) at the end portion on the outer side in the axial direction of the outer diameter side cylinder portion 32a is smaller than the outer diameter of the folded portion 53.

[0120] In this example, the rotating cylinder portion 25 of the slinger 23a is composed only of the inner diameter side cylinder portion 30 of the slinger body 28a, the rotating circular ring portion 26a of the slinger 23a is composed only of the disc portion 31 of the slinger body 28a, and the large diameter side rotating cylinder portion 27a of the slinger 23a is composed of the outer diameter side cylinder portion 32a and the folded back portion 53 of the slinger body 28a.

[0121] The outer peripheral surface of the large diameter side rotating cylinder portion 27a is composed of the outer peripheral surface of the outer diameter side cylinder portion 32a and the outer peripheral surface of the folded-back portion 53. The outer peripheral surface of the outer diameter side cylinder portion 32a is composed of a tapered surface whose outer diameter increases in the axial direction toward the fins 46. In this example, the tapered outer peripheral surface of the outer diameter side cylinder portion 32a prevents foreign matter from entering the seal internal space 50 along the outer peripheral surface of the large diameter side rotating cylinder portion 27a and allows moisture such as muddy water to be guided to the road surface side (vertically downward) like a so-called gutter.

[0122] The inner peripheral surface of the large diameter side rotating cylindrical portion 27a is formed from the inner peripheral surface of the outer diameter side cylindrical portion 32a. The inner peripheral surface of the outer diameter side cylindrical portion 32a is formed from a tapered surface whose inner diameter becomes larger as it approaches the fins 46 in the axial direction.

[0123] The sealing device 5d of this example includes a first labyrinth seal portion 49b between the inner peripheral surface of the annular covering portion 47 and the outer peripheral surface of the large diameter side rotating cylinder portion 27a. The radial width of the first labyrinth seal portion 49b is smaller at the inlet portion of the first labyrinth seal portion 49, where the folded portion 53 is provided, than at other portions.

[0124] Since the outer diameter (maximum outer diameter) at the axially outer end of the outer diameter side cylinder portion 32a is smaller than the outer diameter of the folded portion 53, the radial width of the first labyrinth seal portion 49b is larger at the outlet side portion (the end portion closer to the fin 46 in the axial direction) of the first labyrinth seal portion 49b where the axially outer end of the outer diameter side cylinder portion 32a is located than at the inlet side portion (the end portion farther from the fin 46 in the axial direction) of the first labyrinth seal portion 49b where the folded portion 53 is provided. Therefore, the momentum of the foreign matter that has entered the first labyrinth seal portion 49b can be weakened as it approaches the fin 46. Therefore, the foreign matter can be prevented from entering the seal internal space 50.

[0125] The sealing device 5d is provided with a plurality of fins 46 at a portion axially opposed to the axially outer end face of the large diameter side rotating cylindrical portion 27a (outer diameter side cylindrical portion 32a). Therefore, the plurality of fins 46 can weaken the rotational force of the muddy water that has entered the first labyrinth seal portion 49b. The other configurations and effects are the same as those of the first embodiment.

[0126] Although each example of the embodiment has been described above, the structures of each example of the embodiment can be appropriately combined and implemented as long as no contradiction occurs.

[0127] The technical concept of the present invention is not limited to the structures described in the embodiments. For example, the number and shape of the seal lips provided on the seal ring are not limited to the structures of the examples of the embodiments, and can be changed as appropriate. The shape of the fins provided on the seal ring as viewed in the circumferential direction can also be changed as appropriate. The slinger can also be composed of a slinger body made of a metal material and other members other than the encoder.

[0128] In addition, in the structures of each example of the embodiments, a structure has been described in which the sealing device of the present invention is used to block the axially inner opening of the rolling element installation space, but additionally or alternatively, the sealing device of the present invention can also be used to block the axially outer opening of the rolling element installation space. [Explanation of symbols]

[0129] 1 Hub unit bearing 2 Outer ring 3. Hub 4a, 4b Rolling elements 5, 5a, 5b, 5c, 5d sealing device 6 Sealing device 7a, 7b Outer raceway 8 Stationary Flange 9 Support hole 10a, 10b Inner raceway 11 Rotating flange 12 Pilot Division 13 Spline hole 14 Mounting hole 15 Stud 16 Inner Circle 17 Hub wheel 18 Small diameter stepped section 19 Step surface 20 Crimping part 21a, 21b retainer 22 Rolling element installation space 23, 23a Slinger 24 Seal ring 25 Rotating cylinder 26, 26a Rotating circular part 27, 27a Large diameter rotating cylinder 28, 28a Slinger body 29 Encoder 30 Inner cylinder part 31 Disc section 32, 32a Outside cylinder part 33 Encoder disc section 34, 34a Encoder cylinder 35 Lip 36 Ridge 37 Core 38 Sealing material 39 Fixed cylinder part 40 Fixed ring part 41, 41a Outer flat plate part 42, 42a Inclined plate part 43 Inner flat plate part 44 Seal base 45a, 45b Seal lip 46, 46a, 46b Fins 47 Annular covering part 48 Circular covering part 49, 49a, 49b First labyrinth seal part 50 Seal inner space 51 Interlip space 52, 52a Second labyrinth seal part 53 Folded part 100 Sealing device 101 Slinger 102 Seal ring 103 Hub 104 Rotating cylinder 105 Rotating wheel part 106 Large diameter rotating cylinder 107 Slinger body 108 Encoder 109 Inner cylinder part 110 Disc section 111 Outer cylinder part 112 Encoder disc part 113 Encoder cylinder 114 Core wire 115 Sealing material 116 Outer Ring 117 Fixed cylinder part 118 Fixed ring part 119 Seal base 120a, 120b Seal lip 121 Annular covering part 122 Circular covering part 123 Labyrinth seal part 124 Seal internal space

Claims

1. an outer ring having a double row outer ring raceway on an inner circumferential surface; A hub having a double row inner ring raceway on its outer circumferential 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 seal device having a slinger and a seal ring and closing an axial opening of a rolling element installation space that exists between an inner peripheral surface of the outer ring and an outer peripheral surface of the hub, The slinger has a substantially U-shaped cross section and includes a rotating cylinder portion fitted onto the hub, a rotating annular portion extending radially outward from an axial end of the rotating cylinder portion, and a large diameter rotating cylinder portion disposed radially outward of the rotating cylinder portion so as to overlap the rotating cylinder portion in the radial direction. The seal ring has a core metal and a seal material, the core metal has a fixed cylindrical portion that is fitted and fixed to the outer ring so as to overlap the large diameter side rotating cylindrical portion in the radial direction, and a fixed ring portion that extends radially inward from an axial end portion of the fixed cylindrical portion, The sealing material has at least one seal lip with a tip portion slidingly contacted to the surface of the slinger, an annular covering portion covering the inner peripheral surface of the fixed cylindrical portion, a circular covering portion covering the axial side surface of the fixed circular ring portion, and a plurality of fins provided in a portion axially opposed to the axial end surface of the large diameter side rotating cylindrical portion, The inner circumferential surface of the large-diameter rotating cylinder portion is inclined in the axial direction in a direction in which the inner diameter becomes larger as the inner circumferential surface approaches the fin. Hub unit bearing.

2. The fixed ring portion has an inclined plate portion at a radially intermediate portion, the inclined plate portion being inclined in a direction approaching the rotating ring portion in the axial direction as it goes radially inward, The sealing device has a first labyrinth seal portion between an inner peripheral surface of the annular covering portion and an outer peripheral surface of the large diameter side rotating cylinder portion, the first labyrinth seal portion having a radial width that increases toward the fin in the axial direction, and a second labyrinth seal portion between an outer peripheral surface of a portion of the annular covering portion that covers the outer peripheral surface of the inclined plate portion and the inner peripheral surface of the large diameter side rotating cylinder portion, the second labyrinth seal portion having a radial width that decreases toward the fin in the axial direction.

2. A hub unit bearing according to claim 1.

3. The slinger comprises a slinger body made of a metal material and an encoder supported by the slinger body, The inner circumferential surface of the large diameter rotating cylinder portion is formed by a part of the encoder.

2. A hub unit bearing according to claim 1.

Images