Hub unit bearing

Abstract

To provide a hub unit bearing which can secure a capability for discharging moisture entering a seal internal space between an outer diameter side cylinder part and a seal lip and inhibit entry of moisture into the seal internal space.SOLUTION: A slinger 20 forming a seal device 5 with a seal ring 21 includes a slinger body 28 having a fitting cylinder part 30, a circular ring plate part 31, and an outer diameter side cylinder part 32. The outer diameter side cylinder part 32 is provided with a taper part 33 in which an outer diameter becomes larger in a direction toward the seal ring 21 with respect to an axial direction. Further, in the slinger 20, ridge parts 34a, 34b are provided at a portion of an outer peripheral surface located farther from the seal ring 21 than an axial end surface of the outer diameter side cylinder part 32, which faces the seal ring 21 in the axial direction, with respect to the axial direction.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 a hub, and a seal ring having multiple seal lips, each of whose tip portions is in sliding contact with the surface of the slinger.

[0006] JP 2021-191669 A (Patent Document 1) discloses a structure in which an opening on the axial outer side of a rolling body installation space is blocked by a sealing device having a slinger and a seal ring. On the other hand, JP 2023-29119 A (Patent Document 2) discloses a structure in which an opening on the axial inner side of a rolling body installation space is blocked by a sealing device having a slinger and a seal ring.

[0007] In both of the seal devices described in JP 2021-191669 A and JP 2023-29119 A, the slinger has a cross-sectional shape that is approximately U-shaped (horizontal U-shaped), and has a fitting tube portion fixed to the hub, a circular plate portion extending radially outward from the axial end of the fitting tube portion, and a cylindrical outer diameter side tube portion extending axially from the radially outer end of the circular plate portion and arranged overlapping the fitting tube portion in the radial direction. In addition, the multiple seal lips provided on the seal ring have their respective tip portions in sliding contact with the axial side surface of the circular plate portion and the outer peripheral surface of the fitting tube portion. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] JP 2021-191669 A [Patent Document 2] JP 2023-29119 A Summary of the Invention [Problem to be solved by the invention]

[0009] Slingers having an approximately U-shaped cross-sectional shape are generally manufactured by punching a rust-resistant steel strip to form a circular plate-shaped blank, then burring the blank to form a cylindrical outer diameter side tube portion and a cylindrical mating tube portion from the radially outer and radially inner portions of the blank.

[0010] As shown in Fig. 9, the slinger manufactured by the above-mentioned manufacturing method has a sagging surface 101, a sheared surface 102, a fractured surface 103, and a burr 104 on the axial end surface (tip surface) of the outer diameter side tubular portion 100, in that order from the radially inner side. Therefore, the sagging surface 101 can be used to promote the discharge of moisture that has entered the seal internal space (space in front of the lip) that exists between the outer diameter side tubular portion 100 and the seal lip in the seal device. In addition, the burr 104 can be used to efficiently scatter (shake off) moisture that has adhered to the outer peripheral surface of the outer diameter side tubular portion 100.

[0011] However, when forming the outer diameter side tubular portion by burring processing, spring go (spring in) can occur, and the outer diameter side tubular portion that should have been formed into a cylindrical shape may become (deform) into a tapered conical cylinder shape with the outer diameter becoming smaller toward the tip in the axial direction.

[0012] When the outer diameter side tubular portion is deformed into a tapered conical cylinder shape, the outer diameter side tubular portion may prevent the discharge of moisture that has entered the seal internal space. That is, moisture that has entered the seal internal space moves vertically downward when the vehicle is stopped, flows down the inner peripheral surface of the outer diameter side tubular portion, and is then discharged to the external space through the gap between the tip surface of the outer diameter side tubular portion and the seal ring. However, when the outer diameter side tubular portion has a tapered conical cylinder shape, moisture needs to be discharged against the inclination of the inner peripheral surface of the outer diameter side tubular portion, and therefore the outer diameter side tubular portion may prevent the discharge of moisture from the seal internal space.

[0013] In addition, if the outer diameter side tubular portion has a tapered conical cylindrical shape, moisture adhering to the outer peripheral surface of the outer diameter side tubular portion is likely to be guided along the slope of the outer peripheral surface of the outer diameter side tubular portion into the gap between the tip surface of the outer diameter side tubular portion and the seal ring, which may make it easier for moisture to enter the internal space of the seal.

[0014] 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 moisture that has entered the internal space of the seal between the outer diameter side cylindrical portion and the seal lip, while also preventing moisture from entering the internal space of the seal. [Means for solving the problem]

[0015] 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 comprises a slinger body made of a metal material having a fitting cylindrical portion that is externally fitted onto the hub, a circular plate portion that extends radially outward from the axial end portion of the fitting cylindrical portion, and an outer diameter side cylindrical portion that is positioned radially outward of the fitting cylindrical portion so as to overlap radially with the fitting cylindrical portion and includes a tapered portion whose outer diameter increases axially as it approaches the seal ring, and the slinger has a ridge portion on its outer peripheral surface that is axially farther from the seal ring than the axial end face (tip face) of the outer diameter side cylindrical portion that axially faces the seal ring. The seal ring is fixed to an axial end of the outer ring and has at least one seal lip whose tip is in sliding contact with the surface of the slinger.

[0016] In the hub unit bearing according to one aspect of the present invention, the ridge portion can be provided on an outer circumferential surface of the outer diameter side cylindrical portion. In this case, the ridge portion can be provided on the outer circumferential surface of the tapered portion. The ridge portion can be formed by machining the outer peripheral surface of the outer cylindrical portion. In this case, for example, a groove can be formed by machining the outer peripheral surface of the outer cylindrical portion, and the ridge portion can be provided at the opening edge of the groove.

[0017] When the ridge portion is provided on the outer peripheral surface of the outer diameter side tubular portion, the outer diameter side tubular portion can be composed of the tapered portion and other portions different from the tapered portion, and the ridge portion can be provided on the outer peripheral surface of the other portions. In this case, for example, the outer diameter side tube portion can have the tapered portion and an outward flange portion bent radially outward from the tip of the tapered portion, and the ridge portion can be provided on the outer peripheral surface of the outward flange portion, which is the other portion. Furthermore, in this case, by subjecting the outer peripheral surface of the outward flange to a turning process, the ridge portion can be provided at the portion where the outer peripheral surface of the outward flange intersects with the axial side surface.

[0018] In a hub unit bearing according to one embodiment of the present invention, the slinger body has a folded portion having an approximately U-shaped cross section between the radially outer end of the circular plate portion and the axial end of the outer diameter side cylindrical portion, and the ridge portion can be provided on the outer peripheral surface of the folded portion. In this case, the outer peripheral surface of the folded portion can be subjected to a turning process to provide the ridge portion at the portion where the outer peripheral surface of the folded portion intersects with the axial side surface.

[0019] In a hub unit bearing according to one aspect of the present invention, the slinger has a slinger seal made of an elastic material supported on the slinger body, and the ridge portion can be provided on the outer peripheral surface of the slinger seal. In this case, the outer diameter of the ridge portion can be equal to or larger than the outer diameter of the outer diameter side cylindrical portion. Furthermore, in a cross section relative to an imaginary plane including the central axis of the hub, the angle formed by the two faces connected by the ridge portion can be made an acute angle.

[0020] In the hub unit bearing according to one aspect of the present invention, the sealing device can close an axially outer opening of the rolling element installation space, or the sealing device can close an axially inner opening of the rolling element installation space. In a hub unit bearing according to one aspect of the present invention, two of the sealing devices are provided, and the opening on the axially outer side and the opening on the axially inner side of the rolling element installation space can be sealed. Effect of the Invention

[0021] According to a hub unit bearing according to one aspect of the present invention, it is possible to ensure the discharge of moisture that has entered the internal space of the seal between the outer diameter side cylindrical portion and the seal lip, and to prevent moisture from entering the internal space of the seal. [Brief description of the drawings]

[0022] [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 partially enlarged view of FIG. [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 partially enlarged cross-sectional view of a slinger according to a second example of the embodiment, showing the state before turning is performed on the outer circumferential surface of the outward flange portion. [Figure 6] FIG. 6 is a diagram showing a third example of the embodiment, and corresponds to FIG. [Figure 7] FIG. 7 is a diagram showing a fourth embodiment of the present invention, and corresponds to FIG. [Figure 8] FIG. 8 is a diagram showing a fifth example of the embodiment, and corresponds to FIG. [Figure 9] FIG. 9 is a cross-sectional view showing a tip end portion of an outer diameter side cylindrical portion constituting a slinger of a conventional structure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] [First Example of Implementation] A first example of the embodiment will be described with reference to FIGS. 1 to 3. FIG.

[0024] 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 driven wheel will be described.

[0025] 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 sealing device 5.

[0026] In the following description of hub unit bearing 1, the left side of Figures 1 to 3, which is located on the outer side in the width direction of the vehicle when hub unit bearing 1 is assembled to the vehicle, is referred to as the axial outer side, and the right side of Figures 1 to 3, which is located on the central side in the width direction of the vehicle when hub unit bearing 1 is assembled to the vehicle, is referred to as the axial inner side.

[0027] The outer ring 2 is made of a hard metal such as medium carbon steel. The outer ring 2 has double-row outer ring raceways 6a, 6b on its inner circumferential surface. Furthermore, the outer ring 2 has a stationary flange 7 that protrudes radially outward at an axially intermediate portion. The stationary flange 7 has support holes 8 that penetrate in the axial direction at multiple circumferential positions at the radially intermediate portion.

[0028] In this example, the support hole 8 is configured as a screw hole. The outer ring 2 is supported and fixed to the suspension by a support bolt that is inserted through a through hole provided in the knuckle of the suspension and is screwed into the support hole 8 of the stationary flange 7 from the inside in the axial direction, so that the outer ring 2 does not rotate even when the wheel rotates.

[0029] The hub 3 has double row inner ring raceways 9a, 9b on its outer circumferential surface. The hub 3 also has a rotating flange 10 that protrudes radially outward at a portion that protrudes axially outward beyond the outer ring 2. The hub 3 also has a cylindrical pilot portion 11 at its axially outer end. The hub 3 is disposed radially inward of the outer ring 2 and coaxially with the outer ring 2.

[0030] The rotating flange 10 has mounting holes 12 penetrating in the axial direction at multiple circumferential positions in a radially middle portion. A stud 13 for connecting and fixing a braking rotor such as a disk or drum and a wheel that constitutes a wheel to the rotating flange 10 is press-fitted into each of the mounting holes 12 with serrations. That is, in this example, the mounting holes 12 are cylindrical holes.

[0031] The axially inner surface of the rotatable flange 10 has an inner flat portion 23 on the radially inner side, and an outer flat portion 24 arranged radially outward from the inner flat portion 23 and axially outward from the inner flat portion 23. Furthermore, the axially inner surface of the rotatable flange 10 has a substantially conical cylindrical step portion 25 facing radially outward at the connection between the inner flat portion 23 and the outer flat portion 24, and also has a corner R portion 26 at the radially inner end portion having a generatrix shape that is curved in a curved manner in the axially inward direction as it moves radially inward.

[0032] A braking rotating body such as a brake disc and a wheel of a vehicle are connected and fixed to the rotating flange 10 by inserting a pilot portion 11 into a central hole provided in the center of each of them and inserting a stud 13 into through holes provided at multiple locations circumferentially in the radial middle portion of each of them, and then screwing a hub nut onto the tip of the stud 13.

[0033] 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.

[0034] The hub 3 of this example has a groove shoulder 27 in a portion of its outer peripheral surface that is located between the rotating flange 10 and the axially outer inner ring raceway 9a, i.e., in a portion adjacent to the axially outer side of the axially outer inner ring raceway 9a. In other words, the hub 3 is provided with a groove shoulder 27 in a portion of its outer peripheral surface that faces the axially outer end of the inner peripheral surface of the outer ring 2 in the radial direction.

[0035] The groove shoulder 27 is connected to a corner R portion 26 provided on the axially inner surface of the rotating flange 10, and is also connected to the inner ring raceway 9a on the axially outer side. The groove shoulder 27 is configured to have a cylindrical surface shape and has a linear generatrix shape.

[0036] In this example, the hub 3 is formed by combining an inner ring 14 and a hub ring 15 .

[0037] The inner ring 14 is made of a hard metal such as bearing steel, etc. The inner ring 14 has an inner ring raceway 9b on the axially inner side on its outer circumferential surface.

[0038] The hub ring 15 is made of a hard metal such as medium carbon steel. The hub ring 15 includes an inner ring raceway 9a on the axially outer side, a rotation flange 10, a pilot portion 11, and a groove shoulder portion 27.

[0039] The hub ring 15 has a small diameter step 16 at a portion located axially more inward than the axially outer inner ring raceway 9a, the small diameter step 16 having an outer diameter smaller than that of an adjacent portion on the axially outer side, onto which the inner ring 14 is fitted. Furthermore, the hub ring 15 has a step surface 17 facing axially inward at the axially outer end of the small diameter step 16, and has a crimped portion 18 bent radially outward from the axially inner end of the small diameter step 16.

[0040] The hub 3 is constructed by fitting the inner ring 14 onto the small diameter step 16 of the hub ring 15 and clamping the inner ring 14 from both axial sides between a step surface 17 and a crimping portion 18 of the hub ring 15, thereby joining and fixing the inner ring 14 to the hub ring 15. The hub ring and the inner ring can also be joined by screwing a nut onto the axially inner end of the hub ring that protrudes from the axially inner end of the inner ring.

[0041] Since the hub unit bearing 1 of this example is a hub unit bearing for a driven wheel, the hub 3 is solid. However, the present invention can also be applied to a hub unit bearing for a driving wheel. In this case, the hub has a spline hole penetrating in the axial direction at the center. 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. When the automobile is traveling, the hub is rotated by the drive shaft, thereby rotating and driving the wheels and braking rotors that are joined and fixed to the rotating flange of the hub.

[0042] 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 6a, 6b and the double row inner ring raceways 9a, 9b in a rollable manner while being held by cages 19a, 19b. As a result, the hub 3 is supported on the radial inside of the outer ring 2 so as to be rotatable.

[0043] 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.

[0044] The sealing device 5 is a combined seal ring having a slinger 20 and a seal ring 21, and closes the axially outer opening of the rolling element installation space 22 that exists between the inner peripheral surface of the outer ring 2 and the outer peripheral surface of the hub 3. The slinger 20 and the seal ring 21 are arranged overlapping in the axial direction. In the portion where the slinger 20 and the seal ring 21 overlap in the axial direction, the slinger 20 is arranged on the side farther from the rolling element installation space 22, and the seal ring 21 is arranged on the side closer to the rolling element installation space 22. In the following description, when the axial direction of the slinger 20 is indicated in relation to the seal ring 21, this refers to the relationship at the portion where the slinger 20 and the seal ring 21 overlap in the axial direction.

[0045] The slinger 20 comprises a slinger body 28 made of a metal material having rust-resistant properties, such as a stainless steel plate made of SUS304 or SUS430, and a slinger seal material 29 made of an elastic material such as an elastomer like rubber.

[0046] The slinger body 28 is generally annular and has a substantially U-shaped cross section. The slinger body 28 is produced by punching a steel strip to form a circular plate-shaped blank, and then burring the blank.

[0047] The slinger body 28 has a fitting tubular portion 30 , a circular disk portion 31 , and an outer diameter side tubular portion 32 .

[0048] The fitting tubular portion 30 has a cylindrical shape, and is fitted and fixed to the outside of the hub 3. Specifically, the fitting tubular portion 30 is fitted and fixed to the outside of a groove shoulder portion 27 provided in the hub wheel 15 by press fitting.

[0049] The circular plate portion 31 has a circular plate shape and extends radially outward from the axially outer end of the fitting tubular portion 30. The axially outer surface of the circular plate portion 31 axially faces the inner flat portion 23 and the corner R portion 26 provided on the axially inner surface of the rotating flange 10 with a gap therebetween.

[0050] The outer diameter side cylinder portion 32 is disposed radially outside the fitting cylinder portion 30 so as to overlap radially with the fitting cylinder portion 30. In this example, the outer diameter side cylinder portion 32 extends from the radially outer end of the annular plate portion 31 toward the axially inner side, and a base end portion located axially outward is directly connected to the radially outer end of the annular plate portion 31.

[0051] The maximum outer diameter of the outer diameter side cylindrical portion 32, i.e., the outer diameter at the axially inner end (tip portion) of the outer diameter side cylindrical portion 32, is smaller than the outer diameter at the axially inner end of the step portion 25 that constitutes the axially inner surface of the rotating flange 10, and is smaller than the inner diameter of the axially outer end of the outer ring 2. The outer diameter side cylindrical portion 32 is disposed radially inside the axially outer end of the outer ring 2. The axially inner end face (tip face) of the outer diameter side cylindrical portion 32 is axially closely opposed to the axially outer surface of a seal base 51 (described later) that constitutes the seal ring 21.

[0052] The outer diameter side cylindrical portion 32 has a tapered portion 33 whose outer diameter becomes larger in the axial direction as it approaches the seal ring 21 (rolling element installation space 22), i.e., as it moves axially inward. In this example, the outer diameter side cylindrical portion 32 has the tapered portion 33 over the entire axial direction. In other words, the entire outer diameter side cylindrical portion 32 is composed of the tapered portion 33. Therefore, the outer diameter side cylindrical portion 32 is configured in a tapered cylindrical shape with an outer diameter that becomes larger from the base end side toward the tip end side.

[0053] The inclination angle of the outer diameter side cylinder portion 32 (tapered portion 33) with respect to the central axis of the slinger 20 is not particularly limited, but can be set within the range of 2 degrees to 10 degrees (5 degrees in the illustrated example), for example.

[0054] In this example, even if spring go occurs during the manufacture of the slinger 20 (slinger body 28), the bending angle of the radially outer portion of the blank during burring processing is set slightly (for example, about 2 to 3 degrees) larger than the inclination angle of the outer diameter side cylindrical portion 32 relative to the central axis of the slinger 20 so that the outer diameter side cylindrical portion 32 will have a tapered cylindrical shape.

[0055] The slinger 20 has ridges 34a, 34b, which are sharp corners (edges) formed by the intersection of two surfaces, on the outer peripheral surface of the slinger 20 at a portion (axially outer portion) that is farther from the seal ring 21 (rolling body installation space 22) in the axial direction than the axially inner end face (tip face) of the outer diameter side cylindrical portion 32.

[0056] In particular, in this example, the ridges 34a and 34b are provided on the outer circumferential surface of the outer diameter side cylindrical portion 32 (tapered portion 33).

[0057] The ridges 34a and 34b are provided by forming a groove 35 in the axially intermediate portion of the outer peripheral surface of the outer diameter side cylindrical portion 32 (tapered portion 33). The ridges 34a and 34b are formed on the opening edge portion of the groove 35.

[0058] The groove 35 has a rectangular cross-sectional shape, and is formed by performing a turning process on the axially middle portion of the outer peripheral surface of the outer diameter side cylindrical portion 32. The groove 35 can be formed on a blank, or can be formed on the outer diameter side cylindrical portion 32 that has been subjected to a burring process. The cross-sectional shape of the groove is not limited to a rectangular shape, and can be another shape, such as a U-shape (U-groove).

[0059] The groove depth of the recessed groove 35 is not particularly limited, but may be, for example, about 1 / 4 to 1 / 2 (about 1 / 3 in the illustrated example) of the plate thickness of the outer diameter side tubular portion 32. The groove width of the recessed groove 35 is also not particularly limited, but may be, for example, about 1 / 5 to 1 / 10 (about 1 / 6 in the illustrated example) of the overall length of the outer diameter side tubular portion 32. In this example, only one recessed groove is provided on the outer peripheral surface of the outer diameter side tubular portion, but multiple recessed grooves may be provided on the outer peripheral surface of the outer diameter side tubular portion.

[0060] As shown in Figure 3, the inner surface of the groove 35 is composed of a cylindrical bottom surface 36, a circular ring-shaped first inner surface 37 facing axially outward, and a circular ring-shaped second inner surface 38 facing axially inward.

[0061] The axially inner ridge portion 34a is formed at the intersection of the first inner surface 37 and a portion of the outer peripheral surface of the outer diameter side cylindrical portion 32 that deviates axially inward from the recessed groove 35, and the entire portion has a circular ring shape.

[0062] The axially outer ridge portion 34b is formed at the intersection of the second inner surface 38 and a portion of the outer peripheral surface of the outer diameter side cylindrical portion 32 that deviates axially outward from the recessed groove 35, and the entire portion has a circular ring shape.

[0063] As shown in FIG. 3, the outer diameter side cylindrical portion 32 has, on its axially inner end face axially facing the seal ring 21, a sagging surface 39, a sheared surface 40, a fractured surface 41, and a burr 42, in that order from the radially inner side.

[0064] The slinger seal material 29 has an overall circular ring shape, and is vulcanization bonded to the axially outer surface of the circular plate portion 31 that constitutes the slinger body 28 .

[0065] The slinger seal material 29 comprises an annular base portion 43 fixed to the axially outer surface of the annular plate portion 31 over a range from the radially inner end portion to the radially middle portion, and two lip portions 44a, 44b provided on the radially inner portion of the base portion 43. The base ends of the two lip portions 44a, 44b are integrally formed with each other. Note that Fig. 2 shows the shapes of the lip portions 44a, 44b in their free state.

[0066] Of the two lip portions 44a, 44b, the lip portion 44a disposed on the radially outer side has its tip portion closely facing the corner R portion 26 provided on the axially inner surface of the rotating flange 10 over the entire circumference. The lip portion 44b disposed on the radially inner side has its tip portion in contact with the corner R portion 26 over the entire circumference. This prevents foreign matter such as muddy water from entering the rolling element installation space 22 through the portion between the groove shoulder portion 27 and the fitting tube portion 30. In addition, the lip portion 44a also has the function of providing a gap between the slinger bodies 28 when multiple slingers 20 are stacked vertically, and preventing the base portions 43 and the annular plate portions 31 of the slingers 20 adjacent in the vertical direction from sticking to each other, making it easier to cut out using a fixing device.

[0067] The seal ring 21 is fixed to the axially outer end of the outer ring 2 and has at least one seal lip 45a, 45b whose tip is in sliding contact with the surface of the slinger 20. In this example, the seal ring 21 has two seal lips 45a, 45b. However, the number of seal lips can be less than or greater than two. Note that Fig. 2 shows the shapes of the seal lips 45a, 45b in a free state.

[0068] In this example, the seal ring 21 includes a core metal 46 and a seal material 47 .

[0069] The core bar 46 comprises a core bar fitting tubular portion 48 which is fitted and fixed into the axially outer end portion of the outer ring 2 by an interference fit, an outward flange portion 49 which bends radially outward from the axially outer end portion of the core bar fitting tubular portion 48 and extends radially outward along the axially outer end face of the outer ring 2, and a support plate portion 50 which extends radially inward from the axially inner end portion of the core bar fitting tubular portion 48.

[0070] The seal material 47 constituting the seal ring 21 has a seal base 51, a dam portion 52, and an overhanging lip 53 in addition to the two seal lips 45a, 45b.

[0071] The seal base 51 covers the surfaces of the core wire 46, namely, the inner surface of the core wire fitting tube portion 48, the radial outer portions of the axial outer surface, outer peripheral surface and axial inner surface of the outward flange portion 49, and the radial inner ends of the axial outer surface, inner peripheral surface and axial inner surface of the support plate portion 50.

[0072] A labyrinth seal extending in the axial direction is formed between the portion of the seal base 51 covering the inner peripheral surface of the core metal fitting tubular portion 48 and the outer peripheral surface of the outer diameter side tubular portion 32 of the slinger 20. A labyrinth seal extending in the radial direction is formed between the portion of the seal base 51 covering the axial outer peripheral surface of the support plate portion 50 and the axial inner end face of the outer diameter side tubular portion 32. The inner peripheral surface of the portion of the seal base 51 covering the inner peripheral surface of the core metal fitting tubular portion 48 is configured as a tapered surface whose inner diameter becomes larger toward the axial outside. The axial outer surface of the portion of the seal base 51 covering the axial outer peripheral surface of the support plate portion 50 is configured as a plane existing on a virtual plane perpendicular to the central axis of the seal ring 21.

[0073] The two seal lips 45a, 45b are provided on the radially inner side of the seal ring 21. Of the two seal lips 45a, 45b, the seal lip 45a arranged on the axially outer side is a side lip, which extends from a portion of the seal base 51 that covers the inner peripheral surface of the support plate portion 50 toward the axially outer side and the radially outer side, and has a tip portion in sliding contact with the axially inner side surface of the annular plate portion 31. The seal lip 45b arranged on the axially inner side is a radial lip, which extends from a portion of the seal base 51 that covers the inner peripheral surface of the support plate portion 50 toward the axially inner side and the radially inner side, and has a tip portion in sliding contact with the outer peripheral surface of the fitting tubular portion 30.

[0074] This 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 into the external space through the gap between the slinger 20 and the seal ring 21. Specifically, foreign matter is prevented from entering the rolling element installation space 22 from the external space and grease is prevented from leaking from the rolling element installation space 22 to the external space through an annular seal internal space (lip front space) 54 existing between the outer diameter side cylindrical portion 32 and the seal lip 45a and an annular inter-lip space 55 existing between the two seal lips 45a, 45b.

[0075] The dam portion 52 is provided at a radially outer end portion of the seal ring 21. The dam portion 52 is disposed so as to protrude radially outward from an axially outer end portion of the outer peripheral surface of the outer ring 2.

[0076] The eaves lip 53 extends axially outward from a radially intermediate portion of the axially outer surface of the dam portion 52, with its tip portion closely facing the step portion 25 that constitutes the axially inner surface of the rotating flange 10. A labyrinth seal is formed between the inner peripheral surface of the eaves lip 53 and the outer peripheral surface of the step portion 25. The eaves lip 53 extends radially outward as it moves axially outward.

[0077] The hub unit bearing 1 of this example further includes a cylindrical bearing cap 56 (see FIG. 1) with a bottom that closes the axially inner opening of the rolling element installation space 22. This prevents foreign matter from the external space from entering the rolling element installation space 22 through the opening and prevents grease sealed in the rolling element installation space 22 from leaking into the external space.

[0078] Note that the axially inner opening of the rolling element installation space 22 can also be blocked by a combined seal ring instead of the bearing cap 56. When the axially inner opening of the rolling element installation space 22 is blocked by a combined seal ring, a seal device having a configuration similar to that of the seal device 5 that blocks the axially outer opening of the rolling element installation space 22 with the slinger seal material 29, the outward flange portion 49, the dam portion 52, and the eaves lip 53 omitted can be used as the combined seal ring.

[0079] According to the hub unit bearing 1 of this embodiment, it is possible to ensure the discharge of moisture that has entered the seal internal space 54, and it is also possible to prevent moisture from entering the seal internal space 54.

[0080] That is, in this example, even if a spring go occurs, the outer diameter side tubular portion 32 constituting the slinger 20 is provided with a tapered portion 33 having a conical cylindrical shape whose outer diameter increases in the axial direction as it approaches the seal ring 21 (rolling body installation space 22). Therefore, when the vehicle is stopped, etc., the inclination of the inner peripheral surface of the tapered portion 33 located below the central axis of the hub unit bearing 1 can be used to guide moisture that has entered the seal internal space 54 to the gap between the axially inner end face of the outer diameter side tubular portion 32 and the seal ring 21, which is the outlet of the seal internal space 54. Therefore, the dischargeability of moisture that has entered the seal internal space 54 can be ensured. In addition, when the vehicle is stopped, etc., the inclination of the outer peripheral surface of the tapered portion 33 located above the central axis of the hub unit bearing 1 can be used to move moisture that has adhered to the outer peripheral surface of the outer diameter side tubular portion 32 away from the gap between the axially inner end face of the outer diameter side tubular portion 32 and the seal ring 21, which is the inlet of the seal internal space 54. Therefore, the intrusion of moisture into the seal internal space 54 can be suppressed.

[0081] In addition, in this example, the ridges 34a and 34b are provided on the outer peripheral surface of the outer diameter side tubular portion 32 (tapered portion 33) constituting the slinger 20, so that moisture attached to the outer peripheral surface of the outer diameter side tubular portion 32 can be efficiently scattered (shaken off) radially outward by using the ridges 34a and 34b. The moisture scattered from the ridges 34a and 34b adheres to the inner peripheral surface (tapered surface) of the portion of the seal base 51 that covers the inner peripheral surface of the core metal fitting tubular portion 48, and is then discharged to the external space through the gap between the eaves lip 53 and the step portion 25. Therefore, in this example, the provision of the ridges 34a and 34b on the outer peripheral surface of the outer diameter side tubular portion 32 also makes it possible to suppress the intrusion of moisture into the seal internal space 54.

[0082] In particular, in this example, the ridge portions 34a, 34b are provided by forming a groove 35 on the outer peripheral surface of the outer diameter side tubular portion 32 (tapered portion 33). Therefore, moisture adhering to the outer peripheral surface of the outer diameter side tubular portion 32 can be temporarily retained inside the groove 35 and then scattered away by using the ridge portions 34a, 34b that form the opening edge portion of the groove 35.

[0083] In addition, since a tapered portion 33 is provided over the entire outer diameter side cylindrical portion 32, and the entire outer diameter side cylindrical portion 32 is made into a conical cylindrical shape with a wider tip, moisture that has entered the seal internal space 54 can be efficiently guided to the gap between the tip surface of the outer diameter side cylindrical portion 32 and the seal ring 21.

[0084] Furthermore, in this example, the axially inner end face of the outer diameter side tubular portion 32 is provided with a sag surface 39, a shear surface 40, a fracture surface 41 and a burr 42, in that order from the radially inner side. Therefore, the sag surface 39 can be used to promote the discharge of moisture that has entered the seal internal space 54, and the burr 42 can be used to efficiently disperse moisture adhering to the outer peripheral surface of the outer diameter side tubular portion 32.

[0085] [Second Example of the Implementation Form] The second embodiment will be described with reference to FIGS.

[0086] This example is a modification of the first example of the embodiment, and only the structure of the slinger body 28a of the slinger 20 constituting the sealing device 5 is changed from the structure of the first example of the embodiment.

[0087] The slinger body 28a in this example has a tapered portion 33 extending from the axially outer end to the axially middle portion of the outer diameter side cylindrical portion 32a, and has an outward flange portion 57 at the axially inner end of the outer diameter side cylindrical portion 32a.

[0088] The tapered portion 33 is configured in a conical cylindrical shape whose outer diameter increases in the axial direction toward the seal ring 21 (the rolling element installation space 22). The axially outer end of the tapered portion 33 is directly connected to the radially outer end of the annular plate portion 31.

[0089] The outward flange 57 extends radially outward at a substantially right angle from the axially inner end of the tapered portion 33. The outer peripheral surface of the outward flange 57 is configured as a cylindrical surface, and forms a labyrinth seal with a tapered surface provided on the inner peripheral surface of a portion of the seal base 51 constituting the seal ring 21 that covers the inner peripheral surface of the core metal fitting cylindrical portion 48. The axially inner surface of the outward flange 57 constitutes the axially inner end surface of the outer diameter side cylindrical portion 32a, and forms a labyrinth seal with the axially outer surface of the portion of the seal base 51 that covers the axially outer surface of the support plate portion 50.

[0090] The slinger 20 has a ridge portion 34c on its outer peripheral surface at a portion farther in the axial direction from the seal ring 21 (rolling element installation space 22) than the axially inner end face of the outer diameter side cylindrical portion 32a.

[0091] Specifically, in this example, the ridge portion 34c is provided on the outer peripheral surface of an outward flange portion 57 that constitutes the outer diameter side cylindrical portion 32a of the slinger body 28a.

[0092] The ridge portion 34c is provided at the axially outer end (outer peripheral edge portion) of the outer peripheral surface of the outward flange portion 57 by subjecting the outer peripheral surface of the outward flange portion 57 to a turning process.

[0093] The ridge portion 34c is formed at a portion where the axially outer side surface of the outward flange portion 57 and the outer circumferential surface of the outward flange portion 57 intersect, and has an overall annular shape.

[0094] In the present embodiment as described above, the tapered portion 33 is provided in the range from the axially outer end to the axially intermediate portion of the outer diameter side cylindrical portion 32a, and the outward flange portion 57 is provided at the axially inner end of the outer diameter side cylindrical portion 32a, so that the outward flange portion 57 can prevent moisture from entering the seal internal space 54. In addition, moisture adhering to the outer peripheral surface of the tapered portion 33 can be guided along the outer peripheral surface of the tapered portion 33 to the axially outer surface of the outward flange portion 57, and then efficiently scattered radially outward by using the ridge portion 34c.

[0095] 5, burrs 42a protruding axially outward are formed on the axially outer end of the outer circumferential surface of outward flange 57, making it difficult to dissipate moisture adhering to the axially outer surface of outward flange 57. In this example, burrs 42a are removed and ridges 34c are formed by subjecting the outer circumferential surface of outward flange 57 to turning, so that moisture adhering to the axially outer surface of outward flange 57 can be efficiently dispersed. The other configurations and effects are the same as those of the first embodiment.

[0096] [Third Example of the Implementation Form] A third example of the embodiment will be described with reference to FIG.

[0097] This example is a modification of the second example of the embodiment, and only the structure of the slinger body 28b of the slinger 20 constituting the sealing device 5 is changed from the structure of the second example of the embodiment.

[0098] As in the second example of the embodiment, the slinger body 28b has a tapered portion 33 extending from the axially outer end portion to the axially middle portion of the outer diameter side cylindrical portion 32b, and has an outward flange portion 57a ​​at the axially inner end portion of the outer diameter side cylindrical portion 32b.

[0099] The slinger 20 has ridges 34d, 34e on its outer peripheral surface at a portion farther from the seal ring 21 (rolling element installation space 22) in the axial direction than the axially inner end face of the outer diameter side cylindrical portion 32b.

[0100] The ridges 34d and 34e are provided on the outer peripheral surface of an outward flange portion 57a ​​that constitutes the outer diameter side cylindrical portion 32b of the slinger body 28b.

[0101] The ridges 34d and 34e are provided by performing a turning process (chamfering process) on the axially outer end of the outer circumferential surface of the outward flange portion 57a ​​to form a chamfered portion (C chamfer) 58 in that portion.

[0102] The axially outer ridge portion 34d is formed at the intersection between the axially outer surface of the outward flange portion 57a ​​and the chamfered portion 58, and the axially inner ridge portion 34e is formed at the intersection between the chamfered portion 58 and the outer peripheral surface of the outward flange portion 57a.

[0103] In the above-described example, ridges 34d, 34e can be provided by forming chamfered portion 58 at the axially outer end of the outer peripheral surface of outward flange portion 57a, so that the amount of turning can be reduced compared to the structure of the second example of the embodiment. The other configurations and effects are the same as those of the first and second embodiments.

[0104] [Fourth Example of the Implementation Form] A fourth example of the embodiment will be described with reference to FIG.

[0105] This example is a modification of the first example of the embodiment, and only the structure of the slinger body 28c of the slinger 20 constituting the sealing device 5 is changed from the structure of the first example of the embodiment.

[0106] The slinger body 28c has a fitting tubular portion 30, a circular disk portion 31, an outer diameter side tubular portion 32c, and a folded-back portion 59.

[0107] The folded portion 59 is disposed between the radially outer end of the circular plate portion 31 and the axially outer end of the outer diameter side tubular portion 32c, and connects the circular plate portion 31 and the outer diameter side tubular portion 32c. The folded portion 59 is folded back from the radially outer end of the circular plate portion 31 toward the axially inner side and radially inner side in a substantially U-shaped cross section. A labyrinth seal is formed between the outer peripheral surface of the folded portion 59 and a tapered surface provided on the inner peripheral surface of the portion of the seal base 51 that covers the inner peripheral surface of the core metal fitting tubular portion 48.

[0108] The outer diameter side cylinder portion 32c has the tapered portion 33 over the entire axial direction. In other words, the entire outer diameter side cylinder portion 32c is composed of the tapered portion 33. The outer diameter side cylinder portion 32c of this example has a smaller outer diameter than the outer diameter side cylinder portion 32 of the first example of the embodiment (see FIG. 2). Specifically, the outer diameter side cylinder portion 32c has an outer diameter sufficiently smaller than the folded-back portion 59.

[0109] The slinger 20 has ridges 34f, 34g on the outer peripheral surface at a portion that is axially farther from the seal ring 21 than the axially inner end face of the outer diameter side cylindrical portion 32c. In particular, in this example, the ridges 34f, 34g are provided on the outer peripheral surface of the folded portion 59 that constitutes the slinger body 28c.

[0110] In this example, the outer circumferential surface of the folded portion 59 is formed into a cylindrical surface by performing a turning process on the radially outer end of the folded portion 59, and ridges 34f, 34g are provided on both axial ends (outer circumferential edges) of the folded portion 59. The ridge 34f is provided at a portion where the outer circumferential surface of the folded portion 59 intersects with the axially outer side surface, and the ridge 34g is provided at a portion where the outer circumferential surface of the folded portion 59 intersects with the axially inner side surface.

[0111] In the present embodiment described above, the ridges 34f and 34g can be formed by turning the radially outer end of the turn-back portion 59, so there is no need to turn the outer diameter side tubular portion 32c, and deformation that would reduce the inclination angle of the outer diameter side tubular portion 32c can be prevented. In addition, since the turn-back portion 59 has high rigidity, the workability of the turning process for forming the ridges can be improved compared to other embodiments. The other configurations and effects are the same as those of the first embodiment.

[0112] [Fifth Example of the Implementation Form] A fifth example of the embodiment will be described with reference to FIG.

[0113] In this example, of the slinger body 28d and the slinger seal material 29a that constitute the slinger 20 of the sealing device 5, the slinger seal material 29a is provided with a ridge portion 34h.

[0114] The slinger body 28d has a fitting cylinder portion 30, a circular ring plate portion 31, and an outer diameter side cylinder portion 32d. The outer diameter side cylinder portion 32d has a configuration in which the recessed groove 35 (ridge portions 34a, 34b) is omitted from the outer diameter side cylinder portion 32 (see FIG. 2) of the first example of the embodiment.

[0115] The slinger seal material 29a has an overall circular ring shape, and is vulcanization bonded to the axially outer surface of the circular ring plate portion 31 that constitutes the slinger body 28d.

[0116] The slinger seal material 29a comprises an annular base portion 43a fixed to the axially outer surface of the annular plate portion 31, and two lip portions 44a, 44b provided on the radially inner portion of the base portion 43a.

[0117] The base portion 43a covers the axially outer surface of the annular plate portion 31 over a range from the radially inner end to the radially outer end.

[0118] A ridge 34h is provided at the radially outer end (outer peripheral edge) of the base 43a, where the axially outer side surface of the base 43a and the outer peripheral surface of the base 43a intersect. Therefore, the ridge 34h is provided at a portion of the outer peripheral surface of the slinger 20 that is farther from the seal ring 21 (rolling element installation space 22) in the axial direction than the axially inner end surface of the outer diameter side cylindrical portion 32d.

[0119] In this example, the outer diameter of the ridge portion 34h is approximately the same as the outer diameter of the axially inner end of the outer diameter side cylinder portion 32d. In addition, in a cross section relative to a virtual plane including the central axis of the hub 3, the angle formed between the axially outer side surface of the base portion 43a connected by the ridge portion 34h and the outer peripheral surface of the base portion 43a is an acute angle (approximately 60 degrees in the illustrated example). For this reason, the outer peripheral surface of the base portion 43a is a tapered surface whose outer diameter becomes smaller toward the axially inner side.

[0120] In the present embodiment described above, since the ridge portion 34h is provided on the outer peripheral surface of the base portion 43a constituting the slinger seal material 29a, it is not necessary to perform processing for forming a ridge portion on the slinger body 28d, and therefore the manufacturing cost of the seal device 5 can be reduced. The other configurations and effects are the same as those of the first embodiment.

[0121] 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.

[0122] The technical concept of the present invention is not limited to the structures described in the embodiments. For example, the structure of the seal ring used in combination with the slinger is not limited to the structures of the examples of the embodiments, and can be modified as appropriate. Furthermore, the structure of the slinger seal material that constitutes the slinger is not limited to the structures of the examples of the embodiments, and can be modified as appropriate.

[0123] In addition, in the structures of each example of the embodiments, a structure has been described in which an opening on the axial outer side of the rolling body installation space is blocked by a sealing device having a slinger with a ridge on its outer peripheral surface, but additionally or alternatively, the present invention can also block an opening on the axial inner side of the rolling body installation space by a sealing device having a slinger with a ridge on its outer peripheral surface. [Explanation of symbols]

[0124] 1 Hub unit bearing 2 Outer ring 3. Hub 4a, 4b Rolling elements 5 Sealing device 6a, 6b Outer raceway 7 Stationary Flange 8 Support hole 9a, 9b Inner raceway 10 Rotating flange 11 Pilot Division 12 Mounting hole 13 Stud 14 Inner Circle 15 Hub wheel 16 Small diameter stepped section 17 Step surface 18 Crimping part 19a, 19b retainer 20 Slinger 21 Seal ring 22 Rolling element installation space 23 Inner plane part 24 Outer plane part 25 Step section 26 Corner R 27 Groove shoulder 28, 28a~28d Slinger body 29, 29a Sling seal material 30 Fitting cylinder part 31 Annular plate part 32, 32a~32d Outer diameter side cylinder part 33 Tapered section 34a~34h Ridge 35 Groove 36 Bottom 37 1st inner surface 38 Second inner surface 39 Droopy Face 40 Shear plane 41 Fracture surface 42, 42a Bali 43, 43a base 44a, 44b Lip 45a, 45b Seal lip 46 Core wire 47 Sealing material 48 Core metal fitting cylinder 49 Outward flange 50 Support plate part 51 Seal base 52 Weir 53 Eaves lip 54 Seal inner space 55 Interlip space 56 Bearing cap 57, 57a Outward flange 58 Chamfer 59 Folded part 100 Outer cylinder part 101 Droopy Face 102 Shear plane 103 Fracture surface 104 Bali

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 comprises a slinger body made of a metallic material, the slinger body having a fitting cylindrical portion fitted onto the hub, a circular plate portion extending radially outward from an axial end portion of the fitting cylindrical portion, and an outer diameter side cylindrical portion disposed radially outward of the fitting cylindrical portion so as to overlap radially with the fitting cylindrical portion, the outer diameter side cylindrical portion including a tapered portion whose outer diameter increases axially as it approaches the seal ring, and the slinger body has a ridge portion on its outer peripheral surface at a portion farther from the seal ring in the axial direction than the axial end face of the outer diameter side cylindrical portion that faces the seal ring in the axial direction, The seal ring is fixed to an axial end of the outer ring and has at least one seal lip whose tip is in sliding contact with a surface of the slinger. Hub unit bearing.

2. 2. The hub unit bearing according to claim 1, wherein the ridge portion is provided on an outer circumferential surface of the outer diameter side cylindrical portion.

3. The slinger has a slinger seal member made of an elastic material supported on the slinger body, The ridge portion is provided on the outer peripheral surface of the slinger seal material.

2. A hub unit bearing according to claim 1.

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