Hub unit bearing

Abstract

To prevent careless separation of a seal ring and a slinger and leakage of grease to an external space while suppressing seal torque low.SOLUTION: Slinger 21 includes a slinger main body 23 made of metal, and a slinger sealing member 24 made of an elastic material and coupled and fixed to slinger main body 23. The slinger main body 23 includes a slinger tubular portion 25 that is fitted onto the hub 3, and a slinger circular ring portion 26 that extends radially outward from an end portion of the slinger tubular portion 25 on one side in the axial direction. The slinger seal member 24 includes a cylindrical cover portion 29 that covers the outer peripheral surface of the slinger cylindrical portion 25, and a flange portion 30 that extends radially outward from an end portion of the cylindrical cover portion 29 on the other side in the axial direction, is located on the other side in the axial direction with respect to the radially inner end portion of the seal ring 22, and has an outer diameter larger than the inner diameter of the radially inner end portion of the seal ring 22.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a hub unit bearing for rotatably supporting a wheel of an automobile relative to a suspension system. [Background technology]

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

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

[0004] FIG. 9 shows a hub unit bearing 100 of a conventional structure described in Japanese Patent Application Laid-Open No. 2007-107674.

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

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

[0007] Slinger 105 is fixed to hub 102. Slinger 105 has a slinger cylindrical portion 107 fitted onto hub 102, and a slinger ring portion 108 extending radially outward from the axially inner end of slinger cylindrical portion 107. Slinger ring portion 108 has, at its radially outer end, a tapered portion 109 that is inclined in the axially outward direction as it moves radially outward.

[0008] The seal ring 106 is fixed to the outer ring 101. The seal ring 106 has a core metal 110 fitted inside the outer ring 101 and a seal material 111 coupled to the core metal 110.

[0009] The sealing material 111 has two side lips 112a, 112b, each of whose tip end is in sliding contact with the axial outer surface of the slinger circular ring portion 108, as sliding contact lips that slide against the slinger 105, and one outer lip 113, whose tip end is in sliding contact with the outer peripheral surface of the tapered portion 109.

[0010] In such a hub unit bearing 100, the combined seal ring 104 is provided with two side lips 112a, 112b that can keep the seal torque low, and is not provided with a dust lip (shaft lip) that is likely to increase the seal torque, so it is possible to ensure both sealing performance and low torque.

[0011] Furthermore, in the hub unit bearing 100, the outer lip 113 of the seal ring 106 is in sliding contact with the outer peripheral surface of the tapered portion 109 of the slinger 105, so that the seal ring 106 and the slinger 105 can be prevented from accidentally separating in the axial direction when they are in a single unit before the combined seal ring 104 is attached to the hub unit bearing 100. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-107674 Summary of the Invention [Problem to be solved by the invention]

[0013] In the hub unit bearing 100, it is preferable to make the inter-row distance between the rolling elements arranged in double rows as large as possible in order to improve moment rigidity.

[0014] In order to prevent the axial dimension of hub unit bearing 100 from becoming unnecessarily large while maintaining the inter-row distance, combination seal ring 104 is attached to hub unit bearing 100 so that it does not protrude axially inward from the axially inner end of outer ring 101 or the portion of hub 102 to which slinger cylindrical portion 107 is externally fitted and fixed. For this reason, in hub unit bearing 100 described in JP 2007-107674 A, tapered portion 109 of slinger 105 with which the tip end of outer lip 113 slides is inclined in the axially outward direction as it moves radially outward.

[0015] The processing required to form this type of tapered portion 109 increases the manufacturing cost of the hub unit bearing 100. Furthermore, when an encoder is supported on the axially inner surface of the slinger ring portion 108, the magnetic flux density entering the sensor from the encoder cannot be made sufficiently large, which may make it difficult to ensure the accuracy of detecting the rotation speed, torque, etc. of the hub 102.

[0016] Furthermore, in hub unit bearing 100 described in JP 2007-107674 A, side lips 112a, 112b and outer lip 113 all have shapes that extend closer to the external space as they approach the tip (a shape that allows leakage to occur). For this reason, when grease sealed in annular space 103 is pushed aside by the rolling elements, rides up onto slinger cylindrical portion 107, and moves to the sliding contact portion between lips 112a, 112b, 113 and slinger 105, it is difficult to adequately prevent grease leakage.

[0017] An object of the present disclosure is to provide a hub unit bearing that can prevent accidental separation of the seal ring and slinger and leakage of grease into the external space while keeping seal torque low. [Means for solving the problem]

[0018] A hub unit bearing according to one aspect of the present disclosure includes an outer ring, a hub, a plurality of rolling elements, and a combination seal ring.

[0019] The outer ring has a plurality of outer ring raceways on its inner peripheral surface.

[0020] The hub has a plurality of rows of inner ring raceways on its outer circumferential surface.

[0021] The plurality of rolling elements are disposed so as to roll freely between the plurality of rows of outer ring raceways and the plurality of rows of inner ring raceways.

[0022] The combination seal ring closes an opening on one axial side of an annular space that exists between the inner peripheral surface of the outer ring and the outer peripheral surface of the hub.

[0023] The combination seal ring includes a slinger and a seal ring including a seal member having only a side lip as a sliding lip that slides against the slinger at its tip end.

[0024] The slinger comprises a metal slinger body and a slinger seal member made of an elastic material that is fixedly connected to the slinger body.

[0025] The slinger body includes a slinger cylindrical portion fitted onto the hub, and a slinger ring portion extending radially outward from one axial end of the slinger cylindrical portion.

[0026] The slinger seal material comprises a tube cover portion that covers the outer peripheral surface of the slinger tube portion, and a flange portion that extends radially outward from the other axial end of the tube cover portion, is located on the other axial side of the radially inner end of the seal ring, and has an outer diameter larger than the inner diameter of the radially inner end of the seal ring.

[0027] In one embodiment of the hub unit bearing of the present disclosure, the slinger ring portion may have a through hole that penetrates in the axial direction, and the slinger seal material may further include a ring cover portion that covers one axial side of the slinger ring portion, and a connecting portion that is arranged inside the through hole and connects the tube cover portion and the ring cover portion.

[0028] In the hub unit bearing according to one aspect of the present disclosure, the sealing material may include a grease lip having a tip end portion closely facing the outer circumferential surface of the cylindrical cover portion. [Effects of the Invention]

[0029] According to the hub unit bearing of one aspect of the present disclosure, it is possible to prevent accidental separation of the seal ring and the slinger and leakage of grease into the external space while keeping the seal torque low. [Brief explanation of the drawings]

[0030] [Figure 1] FIG. 1 is a half cross-sectional view showing a hub unit bearing according to a first example of an embodiment of the present disclosure. [Figure 2] FIG. 2 is an enlarged view of the X portion of FIG. [Figure 3] FIG. 3 is a diagram corresponding to FIG. 2 and illustrating a second example of an embodiment of the present disclosure. [Figure 4] FIG. 4 is a diagram corresponding to FIG. 2 and illustrating a third example of an embodiment of the present disclosure. [Figure 5] FIG. 5 is a view corresponding to an enlarged view of a portion Y in FIG. 1 according to a fourth embodiment of the present disclosure. [Figure 6]FIG. 6 is a diagram corresponding to FIG. 5 and illustrating a fifth example of an embodiment of the present disclosure. [Figure 7] FIG. 7 is a diagram corresponding to FIG. 5 and relating to a sixth example of the embodiment of the present disclosure. [Figure 8] FIG. 8 is a diagram corresponding to FIG. 5 and relating to a seventh example of the embodiment of the present disclosure. [Figure 9] FIG. 9 is an enlarged partial cross-sectional view of a hub unit bearing having a conventional structure. DETAILED DESCRIPTION OF THE INVENTION

[0031] [Example 1] A first example of an embodiment of the present disclosure will be described with reference to FIGS.

[0032] [Overall structure of hub unit bearing] The hub unit bearing 1 includes an outer ring 2, a hub 3, a plurality of rolling elements 4a, 4b, and a combination seal ring 5.

[0033] The hub unit bearing 1 of this example is a so-called third-generation hub unit bearing for a driving wheel. However, the hub unit bearing of one embodiment of the present disclosure can also be applied to hub unit bearings for driven wheels, as well as first-, second-, and 2.5-generation hub unit bearings.

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

[0035] The outer ring 2 has a hollow shape and is made of a hard metal such as medium carbon steel. The outer ring 2 has multiple rows of outer ring raceways 6a, 6b on its inner circumferential surface. In this example, the multiple rows of outer ring raceways 6a, 6b are double-row, i.e., two rows of outer ring raceways 6a, 6b.

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

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

[0038] The hub 3 is disposed coaxially with the outer ring 2 and radially inside the outer ring 2. The hub 3 has multiple rows of inner ring raceways 9a, 9b on its outer peripheral surface. In this example, the multiple rows of inner ring raceways 9a, 9b are double rows, i.e., two rows of inner ring raceways 9a, 9b.

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

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

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

[0042] When each mounting hole 12 is configured as a press-fit hole, a stud 50 is press-fitted from the axially inner side into each mounting hole 12. A braking rotating body such as a brake disc and a wheel of a vehicle wheel are coupled and fixed to the rotating flange 10 by inserting the pilot portion 11 into a central hole provided in the center of each and inserting studs 50 into through-holes provided at multiple locations circumferentially in the radially middle portion of each, and screwing hub nuts onto the tips of the studs.

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

[0044] In this example, each of the mounting holes 12 is configured as a press-fit hole, and a stud 50 is press-fitted into each of the mounting holes 12 .

[0045] Furthermore, because the hub unit bearing 1 of this example is a hub unit bearing for a drive wheel, the hub 3 has a spline hole 13 that passes through the hub 3 in the axial direction at its radial center. The tip of a drive shaft that is driven to rotate by an engine or electric motor as a drive source is spline-engaged with the spline hole 13. When the vehicle is running, the hub 3 is driven to rotate by the drive shaft, which in turn drives to rotate the wheel and braking rotor that are coupled and fixed to the rotating flange 10 of the hub 3.

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

[0047] The hub 3 includes an inner ring 14 and a hub ring 15 .

[0048] The inner ring 14 is made of a hard metal such as bearing steel and has a cylindrical shape.

[0049] The inner ring 14 has at least the axially innermost inner ring raceway 9b of the multiple rows of inner ring raceways 9a, 9b on its outer peripheral surface. In this example, the inner ring 14 has the axially innermost inner ring raceway 9b of the double row of inner ring raceways 9a, 9b on its outer peripheral surface at an axially middle portion.

[0050] Of the multiple rows of inner ring raceways 9a, 9b, at least the axially outermost inner ring raceway 9a is provided on the outer peripheral surface of the hub ring 15. In this example, the axially outermost inner ring raceway 9a of the double row of inner ring raceways 9a, 9b is provided on the outer peripheral surface of the axially middle portion of the hub ring 15.

[0051] The hub ring 15 has a rotation flange 10 at a portion located axially outward of the inner ring raceway 9a on the axially outer side, and also has a pilot portion 11 at the axially outer end.

[0052] Furthermore, the hub ring 15 has a fitting shaft portion 16 at a portion axially more inward than the axially outer inner ring raceway 9a, the fitting shaft portion having an outer diameter smaller than the outer diameter of the portion adjacent to it on the axially outer side. The hub ring 15 has a stepped surface 17 that connects the portion of its outer peripheral surface adjacent to it on the axially inner side of the axially outer inner ring raceway 9a with the outer peripheral surface of the fitting shaft portion 16, and faces axially inward.

[0053] The inner ring 14 is fixedly coupled to the hub ring 15 by abutting its outer axial end face against a stepped surface 17 of the hub ring 15 and by being fitted tightly onto the mating shaft portion 16 of the hub ring 15.

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

[0055] Because the hub unit bearing 1 of this example is a so-called third-generation hub unit bearing, the hub ring 15 is made entirely of a hard metal such as medium carbon steel. However, for example, when a hub unit bearing according to one embodiment of the present disclosure is applied to a so-called second-and-a-half-generation hub unit bearing, the hub ring can also be formed by combining a hub spindle having a rotation flange and a pilot portion with a separate inner ring having an inner ring raceway on the axially outer side of its outer peripheral surface.

[0056] The rolling elements 4a, 4b are arranged rollably between the multiple rows of outer ring raceways 6a, 6b and the multiple rows of inner ring raceways 9a, 9b, with multiple rolling elements in each row. In this example, the rolling elements 4a, 4b are arranged rollably at equal intervals in the circumferential direction between the double rows of outer ring raceways 6a, 6b and the double rows of inner ring raceways 9a, 9b, with multiple rolling elements in each row held by cages 18a, 18b. A back-to-back (DB) type contact angle is imparted to the rolling elements 4a, 4b arranged in the double rows.

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

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

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

[0060] The combined seal ring 5 closes the axially inner opening of the annular space 19 that exists between the inner peripheral surface of the outer ring 2 and the outer peripheral surface of the hub 3. Therefore, in the following description of the combined seal ring 5, the axially inner side corresponds to one axial side in the claims, and the axially outer side corresponds to the other axial side in the claims.

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

[0062] The hub unit bearing 1 of this example further has a sealing device 20 that closes the axially outer opening of the annular space 19. The sealing device 20 is not limited to this, but can be configured, for example, by a seal ring that includes a core bar that is fitted and fixed to the axially outer end of the outer ring 2, at least one seal lip whose tip end is in sliding contact with the surface of the hub 3 or a slinger that is fitted and fixed to the outside of the hub 3, and a seal material that is bonded and fixed to the core bar by vulcanization adhesion. In this example, the sealing device 20 is configured by a seal ring, and the tip end of the seal lip of this seal ring is in direct sliding contact with the outer peripheral surface of the hub 3.

[0063] The combined seal ring 5 and the seal device 20 prevent leakage of grease (not shown) sealed in the annular space 19 and also prevent foreign matter such as muddy water from entering the annular space 19 .

[0064] [Structure of combined seal ring] The combination seal ring 5 includes a slinger 21 and a seal ring 22. The slinger 21 is fixed to the hub 3 and rotates during use. In contrast, the seal ring 22 is fixed to the outer ring 2 and does not rotate during use.

[0065] Slinger The slinger 21 comprises a metal slinger body 23 and a slinger seal member 24 made of an elastic material and fixedly connected to the slinger body 23 .

[0066] The slinger body 23 is formed into an annular shape by bending a metal plate such as a cold-rolled steel plate. The slinger body 23 includes a slinger tube portion 25 and a slinger ring portion 26.

[0067] The slinger cylindrical portion 25 is fitted onto the outside of the hub 3. In this example, the slinger cylindrical portion 25 is fitted onto the axially inner end of the inner ring 14 that constitutes the hub 3 by an interference fit.

[0068] Slinger ring portion 26 extends radially outward from the axially inner end of slinger tube portion 25. In this example, the axially inner surface of slinger ring portion 26 is configured as a flat surface that is approximately perpendicular to the central axis of slinger body 23, except for both radial end portions.

[0069] Slinger ring portion 26 also has, as an optional component, through-hole 27 that penetrates in the axial direction. Through-hole 27 axially penetrates the radially inner portion of slinger ring portion 26. Through-hole 27 is the portion where connecting portion 33 that connects tube covering portion 29 and ring covering portion 32 that constitute slinger seal material 24 is located.

[0070] The through-holes 27 are provided at one or more locations in the circumferential direction of the slinger ring portion 26. In this example, the through-holes 27 are provided at multiple locations at equal intervals in the circumferential direction on the radially inner part of the slinger ring portion 26.

[0071] In this example, slinger body 23 has, as an optional component, outer tubular portion 28 extending axially outward from the radially outer end of slinger ring portion 26. Outer tubular portion 28 is disposed approximately coaxially with slinger tubular portion 25, and has an axial dimension that is shorter than the axial dimension of slinger tubular portion 25. Therefore, in this example, slinger body 23 has a cross-sectional shape that is approximately horizontally U-shaped or approximately horizontally J-shaped.

[0072] The slinger seal member 24 is made of an elastic material such as an elastomer like rubber, and includes a cylindrical cover portion 29 and a flange portion 30 .

[0073] The cylinder cover portion 29 covers the outer peripheral surface of the slinger cylinder portion 25. In this example, the cylinder cover portion 29 covers the outer peripheral surface of the slinger cylinder portion 25 over the entire axial length and the entire circumference.

[0074] The flange portion 30 extends radially outward from the axially outer end of the cylindrical covering portion 29, is positioned axially outward from the radially inner end of the seal ring 22, and has an outer diameter larger than the inner diameter of the radially inner end of the seal ring 22.

[0075] In this example, the flange portion 30 is located axially outward from the portion of the base 41 of the sealing material 37 constituting the seal ring 22 that covers the radially inner end of the axially outer surface of the core metal ring portion 40 of the core metal 38, and has an outer diameter that is larger than the inner diameter of the portion of the base 41 that covers the inner surface of the core metal ring portion 40.

[0076] In this example, both axial side surfaces of the flange portion 30 are configured as flat surfaces that are parallel to each other and approximately perpendicular to the central axis of the seal ring 22. Therefore, the flange portion 30 has a substantially rectangular or trapezoidal cross-sectional shape. The radially outer portion of the axially inner surface of the flange portion 30 is positioned closely opposite to a portion of the base 41 that covers the radially inner end of the axially outer surface of the core ring portion 40, thereby forming a radial labyrinth seal 31 between these surfaces.

[0077] The slinger seal 24 includes a circular ring cover portion 32 and a connecting portion 33 as optional components.

[0078] The circular ring cover portion 32 covers the axial inner surface of the slinger circular ring portion 26. In this example, the circular ring cover portion 32 covers the axial inner surface of the slinger circular ring portion 26 over the entire radial length and the entire circumference.

[0079] In this example, the circular cover portion 32 has a detection surface 34 on its axially inner surface, where north and south poles are alternately and equally spaced in the circumferential direction. In other words, the circular cover portion 32 functions as an encoder. For this reason, in this example, the slinger seal material 24 is made of rubber (magnetic rubber) mixed with magnetic powder. The detection surface 34 is made of a flat surface that is approximately perpendicular to the central axis of the slinger 21.

[0080] In this example, the axially inner surface of slinger 21 and the axially inner surface of the portion of hub 3 to which slinger 21 is fitted and fixed (the portion adjacent to the radially inner side of slinger 21) are located on approximately the same imaginary plane (their axial positions are approximately the same). More specifically, the axially inner surface (detected surface 34) of ring cover portion 32 and the axially inner end face of inner ring 14 are located on approximately the same imaginary plane.

[0081] The connecting portion 33 is disposed inside the through-hole 27 and connects the cylindrical covering portion 29 and the annular covering portion 32. As a result, the slinger seal material 24 is constructed as a single unit.

[0082] Furthermore, in this example, the slinger seal material 24 has a gasket portion 35 and an outer cover portion 36 .

[0083] The gasket portion 35 is provided so as to protrude radially inward from the radially inner end of the annular cover portion 32. The gasket portion 35 elastically abuts against the outer peripheral surface of the hub 3. This prevents foreign matter from entering the annular space 19 from the external space through the gap between the inner peripheral surface of the slinger tube portion 25 and the outer peripheral surface of the hub 3, and prevents grease filled in the annular space 19 from leaking into the external space. In this example, the gasket portion 35 elastically abuts against the outer peripheral surface of the axially inner end of the inner ring 14.

[0084] The outer covering portion 36 covers the outer peripheral surface of the outer tubular portion 28 over the entire axial length and circumference. The axially inner end of the outer covering portion 36 is connected to the radially outer end of the annular covering portion 32.

[0085] The slinger 21 is constructed by bonding and fixing the slinger seal 24 to the slinger body 23 by vulcanization adhesion. Specifically, the slinger body 23, whose surface is coated with an adhesive, is placed in a mold cavity, and the material that forms the slinger seal 24 is fed into a portion of the cavity that is axially outer (or axially inner) than the slinger ring portion 26. This material is fed through the through-hole 27 into a portion of the cavity that is axially inner (or axially outer) than the slinger ring portion 26. After filling the cavity with the material in this manner, it is cooled and solidified within the cavity, thereby forming the slinger seal 24 and simultaneously bonding it to the slinger body 23.

[0086] <Seal ring> The seal ring 22 includes a seal member 37 having only a side lip as a sliding lip that brings its tip into sliding contact with the slinger 21. In other words, the seal member 37 does not have a grease lip or dust lip that has a radial interference between it and the slinger 21.

[0087] In this example, the seal ring 22 further includes a core metal 38 in addition to the seal material 37 .

[0088] The core 38 is formed into an annular shape by bending a metal plate such as a cold-rolled steel plate. The core 38 includes a tubular core portion 39 fitted and fixed to the outer ring 2, and a circular core portion 40 extending radially inward from the axially outer end of the tubular core portion 39. Therefore, in this example, the core 38 has a substantially L-shaped cross section. In addition, in this example, the tubular core portion 39 is fitted and fixed to the axially inner end of the outer ring 2 by an interference fit.

[0089] The seal member 37 is made of an elastic material such as an elastomer like rubber, and is bonded and fixed to the core metal 38 by vulcanization adhesion or the like. In this example, the seal member 37 has a base portion 41 in addition to a side lip 42.

[0090] The base 41 is bonded and fixed to the surface of the core 38. In this example, the base 41 is bonded and fixed to the core 38 so as to cover the range of the core 38 from the axially inner end of the outer circumferential surface of the core tube portion 39 to the radially inner portion of the axially outer surface of the core ring portion 40. In other words, the base 41 covers the axially inner end outer circumferential surface, axially inner end face, and inner circumferential surface of the core tube portion 39, as well as the axially inner side surface, inner circumferential surface, and axially outer side surface of the radially inner portion of the core ring portion 40.

[0091] In this example, the axially inner portion of the base 41 that covers the inner peripheral surface of the core tube portion 39 is positioned closely opposite the outer peripheral surface of the outer cover portion 36 of the slinger 21, and an axial labyrinth seal 43 is formed between them. This prevents foreign matter from entering the area between the slinger 21 and the seal ring 22 and reaching the sliding contact area between the tip of the side lip 42 and the slinger 21.

[0092] The tip of the side lip 42 is in sliding contact with the axially facing surface of the slinger 21. In this example, the tip of the side lip 42 is in sliding contact with the axially outer surface of the slinger ring portion 26. The base end of the side lip 42 is connected to the base portion 41, and has a generally conical cylindrical shape that extends radially outward as it moves axially inward.

[0093] In this example, the sealing material 37 has only one side lip 42. The base end of one side lip 42 is connected to the radially inner end of the portion of the base 41 that covers the axially inner surface of the core metal ring portion 40, and the tip end thereof is in sliding contact with the radially middle portion of the axially outer surface of the slinger ring portion 26. However, in a hub unit bearing according to one aspect of the present disclosure, the sealing material may also have multiple side lips.

[0094] In addition, in the hub unit bearing of one aspect of the present disclosure, the sealant can also be provided with a non-contact lip that does not bring its tip into sliding contact with the slinger. For example, the sealant can be provided with a grease lip whose tip is closely opposed to the outer circumferential surface of the slinger (the outer circumferential surface of the sleeve cover). In this example, the sealant 37 does not have a non-contact lip.

[0095] In the hub unit bearing 1 of this example, the seal material 37 of the seal ring 22 that constitutes the combination seal ring 5 has only a side lip 42 as a sliding lip that brings its tip into sliding contact with the slinger 21. In other words, the seal material 37 has a radial interference with the slinger 21 as a sliding lip, and does not have a grease lip or dust lip that tend to increase the seal torque. Therefore, with the hub unit bearing 1 of this example, the seal torque can be kept low compared to a structure that has a grease lip and / or dust lip.

[0096] Furthermore, the slinger seal material 24 of the slinger 21 constituting the combination seal ring 5 has a flange portion 30 that extends radially outward from the axially outer end of the cylindrical covering portion 29. The flange portion 30 is located axially outward of the radially inner end of the seal ring 22, and has an outer diameter larger than the inner diameter of the radially inner end of the seal ring 22.

[0097] Therefore, when the slinger 21 and the seal ring 22 attempt to move relative to each other in the axial direction away from each other, the flange portion 30 engages (contacts) with the radially inner end of the seal ring 22. This prevents the slinger 21 and the seal ring 22 from being accidentally separated.

[0098] Furthermore, even if the grease sealed in the annular space 19 is pushed aside by the rolling element 4b on the axially inner side, the flange portion 30 and the labyrinth seal 31 can prevent the grease from climbing up onto the outer surface of the cylindrical covering portion 29, thereby preventing the grease from leaking into the external space.

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

[0100] In this example, the seal member 37a of the seal ring 22a constituting the combination seal ring 5a has a grease lip 44 which is a non-contact lip that does not bring the tip portion of the seal member 37a into sliding contact with the slinger 21.

[0101] The tip of the grease lip 44 is positioned closely opposite the outer peripheral surface of the cylindrical cover portion 29 of the slinger 21. The base end of the grease lip 44 is connected to the portion of the base portion 41 of the sealing material 37a that covers the inner peripheral surface of the core metal ring portion 40, and has a generally conical cylindrical shape that extends axially outward as it extends radially inward.

[0102] In this example, the flange portion 30 is located axially outward of the tip end of the grease lip 44 and has an outer diameter larger than the inner diameter of the tip end of the grease lip 44 .

[0103] According to this example, even if grease displaced by the axially inner rolling element 4b were to climb over the flange portion 30 and reach the outer peripheral surface of the cylinder cover portion 29, the grease lip 44 can prevent the grease from moving to the sliding contact portion between the tip end of the side lip 42 and the axially outer surface of the slinger ring portion 26. In other words, the hub unit bearing of this example can more effectively prevent grease from leaking into the external space than the hub unit bearing 1 of the first example.

[0104] The configuration and effects of other parts of the second example are the same as those of the first example.

[0105] [Example 3] A third example of the embodiment of the present disclosure will be described with reference to FIG.

[0106] In this example, too, the seal member 37b of the seal ring 22b constituting the combination seal ring 5b is provided with a grease lip 44a which is a non-contact lip.

[0107] The tip of the grease lip 44a faces closely to the outer peripheral surface of the cylindrical cover portion 29 of the slinger 21. The base end of the grease lip 44a is connected to the portion of the base portion 41 of the sealing material 37b that covers the inner peripheral surface of the core ring portion 40, and has a generally conical cylindrical shape that extends axially inward as it moves radially inward. That is, in this example, the inclination direction of the grease lip 44a is opposite to the inclination direction of the grease lip 44 of the second example.

[0108] In this example as well, the flange portion 30 is located axially outward of the tip end of the grease lip 44a and has an outer diameter larger than the inner diameter of the tip end of the grease lip 44a.

[0109] In this example, if the grease displaced by the axially inner rolling element 4b were to climb over the flange portion 30 and reach the outer peripheral surface of the tube cover portion 29, the grease would be allowed to move to a certain extent up to the sliding contact portion between the tip end of the side lip 42 and the axially outer surface of the slinger ring portion 26. On the other hand, if a foreign object from the external space were to enter the radially inner side of the side lip 42, the grease lip 44a would prevent the foreign object from moving up to the annular space 19.

[0110] The configuration and effects of other parts of the third example are similar to those of the first and second examples.

[0111] [Example 4] A fourth example of the embodiment of the present disclosure will be described with reference to FIG.

[0112] In this example, the combined seal ring 5c ​​closes the opening on the axially outer side of the annular space 19 that exists between the inner peripheral surface of the outer ring 2 and the outer peripheral surface of the hub 3. That is, in this example, instead of the seal device 20 configured by a seal ring having a seal lip whose tip end is in sliding contact with the outer peripheral surface of the hub 3, the opening on the axially outer side of the annular space 19 is closed by the combined seal ring 5c ​​that includes a slinger 21a and a seal ring 22c. In the following description of the combined seal ring 5c, the axially outer side corresponds to one axial side in the claims, and the axially inner side corresponds to the other axial side in the claims.

[0113] Slinger The slinger 21a includes a slinger body 23a and a slinger seal member 24a.

[0114] The slinger body 23a includes a slinger cylindrical portion 25a and a slinger ring portion 26a.

[0115] The slinger cylindrical portion 25a is fitted onto the outside of the hub 3. In this example, the slinger cylindrical portion 25a is fitted onto and fixed to an axially intermediate portion of the hub ring 15 that constitutes the hub 3, the axially outer portion being located between the inner ring raceway 9a and the rotating flange 10.

[0116] Slinger ring portion 26a extends radially outward from the axially outer end of slinger tube portion 25a. Slinger ring portion 26a has through-holes 27a that penetrate in the axial direction at multiple locations around the circumference of its radially inner portion.

[0117] Slinger body 23a further has outer tubular portion 28a extending axially inward from the radially outer end of slinger ring portion 26a. Outer tubular portion 28a is disposed approximately coaxially with slinger tubular portion 25a and has an axial dimension shorter than the axial dimension of slinger tubular portion 25a.

[0118] The slinger body 23a is formed by bending a metal plate such as a cold-rolled steel plate into a generally circular ring shape with a substantially horizontal U-shaped or horizontal J-shaped cross section.

[0119] The slinger seal 24a includes a cylinder cover portion 29a and a flange portion 30a.

[0120] The cylinder cover 29a covers the outer peripheral surface of the slinger cylinder 25a. In this example, the cylinder cover 29a covers the outer peripheral surface of the slinger cylinder 25a over the entire axial length and the entire circumference.

[0121] The flange portion 30a extends radially outward from the axially inner end of the cylindrical covering portion 29a, is positioned axially inward of the radially inner end of the seal ring 22c, and has an outer diameter larger than the inner diameter of the radially inner end of the seal ring 22c.

[0122] In this example, the flange portion 30a is located axially inward of the portion of the base 41a of the sealing material 37c that constitutes the seal ring 22c that covers the radially inner end of the axially inner surface of the core ring portion 40a of the core 38a, and has an outer diameter that is larger than the inner diameter of the portion of the base 41a that covers the inner peripheral surface of the core ring portion 40a.

[0123] In this example, the flange portion 30a has a radially outer portion of its axially outer surface closely opposed to a portion of the base portion 41a that covers the radially inner end of the axially inner surface of the core metal ring portion 40a, thereby forming a radial labyrinth seal 31a between these surfaces.

[0124] The slinger seal 24a further includes a circular ring cover portion 32a, a connection portion 33a, and a gasket portion 35a.

[0125] The circular ring cover portion 32a covers the axially outer surface of the slinger circular ring portion 26a. In this example, the circular ring cover portion 32a covers the entire radially inner portion of the axially outer surface of the slinger circular ring portion 26a.

[0126] The connecting portion 33a is disposed inside the through-hole 27a and connects the cylindrical covering portion 29a and the annular covering portion 32a, thereby forming the slinger seal material 24a as a single unit.

[0127] The gasket portion 35a is provided so as to bulge axially outward from a radially inner portion of the axially outer surface of the annular cover portion 32a. The gasket portion 35a elastically abuts against a portion of the outer peripheral surface of the hub wheel 15 that is adjacent to the axially outer side of the portion on which the slinger cylindrical portion 25a is fitted. This prevents foreign matter from entering the annular space 19 from the external space through the portion between the inner peripheral surface of the slinger cylindrical portion 25a and the outer peripheral surface of the hub 3, and prevents grease filled in the annular space 19 from leaking into the external space.

[0128] <Seal ring> The seal ring 22c includes a core metal 38a and a seal material 37c.

[0129] The core 38a comprises a core tubular portion 39a that is tightly fitted and secured to the axially outer end of the outer ring 2, a core circular ring portion 40a that extends radially inward from the axially inner end of the core tubular portion 39a, and an outer circular ring portion 45 that extends radially outward from the axially outer end of the core tubular portion 39a. The axially inner surface of the outer circular ring portion 45 abuts against the axially outer end face of the outer ring 2 via a part of the base portion 41a of the seal material 37c. The core 38a is formed into an overall ring shape with a generally crank-shaped cross section by bending a metal plate such as a cold-rolled steel plate.

[0130] The seal 37c is made of an elastic material such as an elastomer, and is bonded and fixed to the core 38a by vulcanization adhesion or the like. In this example, the seal 37c includes a base 41a and a side lip 42a. In this example, the seal 37c does not include a grease lip or dust lip that provides radial interference with the slinger 21a.

[0131] The base 41a is bonded and fixed to the surface of the core 38a. In this example, the base 41a is bonded and fixed to the core 38a so as to cover the range of the core 38a from the radially outer portion of the axially inner surface of the outer circular ring portion 45 to the radially inner portion of the axially inner surface of the core ring portion 40a. In other words, the base 41a covers the axially inner surface, outer surface, and axially outer surface of the radially outer portion of the outer circular ring portion 45, the inner peripheral surface of the core tube portion 39a, and the axially outer surface, inner peripheral surface, and axially inner surface of the radially inner portion of the core ring portion 40a.

[0132] In this example, the sealing material 37c has only one side lip 42a. The base end of the side lip 42a is connected to the radially inner end of the portion of the base 41a that covers the axially outer surface of the core ring portion 40a, and the tip end thereof is in sliding contact with the radially middle portion of the axially inner surface of the slinger ring portion 26a. However, the sealing material may have multiple side lips.

[0133] In this example, the sealing material 37c further includes a dam portion 46 and a labyrinth slip 47.

[0134] Weir portion 46 protrudes radially outward from a portion of base portion 41a that covers the outer peripheral surface of outer circular ring portion 45. The radially outer portion of weir portion 46 protrudes radially outward from the axially outer end face of outer ring 2. Weir portion 46 blocks moisture that adheres to the outer peripheral surface of outer ring 2 and moves axially outward along said outer peripheral surface, preventing the moisture from entering the area between slinger 21a and seal ring 22c from between the axially outer end face of outer ring 2 and the axially inner surface of rotating flange 10.

[0135] The labyrinth slip 47 extends axially and radially outward in a conical cylindrical shape from a portion of the base 41a that covers the axially outer surface of the outer circular ring portion 45. The tip end surface (axially outer end surface) of the labyrinth slip 47 closely faces the radially middle portion of the axially inner surface of the rotating flange 10. This forms a labyrinth seal 48 between the labyrinth slip 47 and the hub 3.

[0136] In this example, the sealing material 37c also has only the side lip 42a as a sliding lip that causes its tip to slide against the slinger 21a. Therefore, according to this example, the sealing torque can be kept low compared to a structure that has a grease lip and / or dust lip as a sliding lip.

[0137] Furthermore, the flange portion 30a of the slinger seal 24a is located axially inward of the radially inner end of the seal ring 22c and has an outer diameter larger than the inner diameter of the radially inner end of the seal ring 22c. Therefore, when the slinger 21a and the seal ring 22c attempt to move relative to each other in the axial direction, the flange portion 30a and the radially inner end of the seal ring 22c engage (contact) with each other. This prevents the slinger 21a and the seal ring 22c from accidentally separating from each other. Furthermore, even if the grease sealed in the annular space 19 is pushed aside by the axially outer rolling element 4a, the grease can be prevented from climbing up onto the outer peripheral surface of the sleeve cover portion 29a, thereby preventing the grease from leaking into the external space.

[0138] The configuration and effects of other parts of the fourth example are the same as those of the first example.

[0139] [Example 5] A fifth example of the embodiment of the present disclosure will be described with reference to FIG.

[0140] In this example, flange portion 30b of slinger seal member 24b constituting slinger 21b has a generally arc-shaped cross section that curves axially inward as it extends radially outward. Therefore, when grease pushed aside by rolling elements 4a on the axially outer side attempts to run onto the outer peripheral surface of sleeve cover portion 29a, it is pushed back axially inward by the axially inner surface of flange portion 30b. Therefore, this example more effectively prevents grease from running onto the outer peripheral surface of sleeve cover portion 29a.

[0141] In this example, the metal core 38b constituting the seal ring 22d has only a metal core tube portion 39a and a metal core ring portion 40a, and the seal material 37d has only a base portion 41a and a side lip 42a. That is, the metal core 38b does not have an outer ring portion, and the seal material 37d does not have a dam portion or a labyrinth lip, thereby simplifying the structure of the seal ring 22d.

[0142] In this example, the outer ring 2a is provided with a groove 49 recessed radially inward along the entire circumference on the outer peripheral surface at the axially outer end. Groove 49 captures moisture that adheres to the outer peripheral surface of the outer ring 2a and moves axially outward along the outer peripheral surface, preventing the moisture from entering the area between the slinger 21b and seal ring 22d from between the axially outer end face of the outer ring 2a and the axially inner surface of the rotating flange 10.

[0143] The configuration and effects of other parts of the fifth example are the same as those of the first and fourth examples.

[0144] [Example 6] A sixth example of the embodiment of the present disclosure will be described with reference to FIG.

[0145] In this example, the seal member 37e constituting the seal ring 22e is provided with a grease lip 44b, which is a non-contact lip whose tip does not slide against the slinger 21a. The tip of the grease lip 44b is positioned closely opposite the outer circumferential surface of the cylindrical cover portion 29a of the slinger 21a. The base end of the grease lip 44b is connected to the portion of the base portion 41a of the seal member 37e that covers the inner circumferential surface of the core ring portion 40a, and has a generally conical cylindrical shape that extends axially inward as it extends radially inward.

[0146] In this example, the flange portion 30a is located axially inward of the tip end of the grease lip 44b, and has an outer diameter larger than the inner diameter of the tip end of the grease lip 44b.

[0147] In this example, even if the grease displaced by the axially inner rolling element 4a somehow climbs over the flange portion 30a and moves to the outer peripheral surface of the tube cover portion 29a, the grease lip 44b can prevent the grease from moving to the sliding contact portion between the tip of the side lip 42a and the axially inner surface of the slinger ring portion 26a.

[0148] The configuration and effects of other parts of the sixth example are similar to those of the first, second and fourth examples.

[0149] [Example 7] A seventh example of the embodiment of the present disclosure will be described with reference to FIG.

[0150] In this example, too, the seal member 37f constituting the seal ring 22f has a grease lip 44c, which is a non-contact lip whose tip does not come into sliding contact with the slinger 21a. In this example, the grease lip 44c has a generally conical cylindrical shape that extends radially inward and axially outward.

[0151] In this example, the flange portion 30a is located axially inward of the tip end of the grease lip 44c, and has an outer diameter larger than the inner diameter of the tip end of the grease lip 44c.

[0152] In this example, if the grease displaced by the axially outer rolling element 4a were to climb over the flange portion 30a and reach the outer peripheral surface of the sleeve cover portion 29a, the grease would be allowed to move to a certain extent up to the sliding contact portion between the tip end of the side lip 42a and the axially inner surface of the slinger ring portion 26a. On the other hand, if a foreign object from the external space were to enter the radially inner side of the side lip 42a, the grease lip 44c would prevent the foreign object from moving up to the annular space 19.

[0153] The configuration and effects of other parts of the seventh example are the same as those of the first to sixth examples.

[0154] The first to seventh examples of the embodiment of the present disclosure can be implemented in any suitable combination as long as no contradiction occurs. [Explanation of symbols]

[0155] 1 Hub unit bearing 2, 2a outer ring 3. Hub 4a, 4b rolling elements 5, 5a, 5b, 5c combination seal ring 6a, 6b Outer raceway 7 Stationary Flange 8 Flange side support hole 9a, 9b Inner raceway 10 Rotating flange 11 Pilot Division 12 Mounting holes 13 Spline hole 14 Inner Circle 15 Hub wheel 16 Mating shaft 17 Step surface 18a, 18b retainer 19 Annular Space 20 Sealing device 21, 21a Slinger 22, 22a, 22b, 22c, 22d, 22e, 22f seal ring 23, 23a Slinger body 24, 24a, 24b Slinger seal material 25, 25a Slinger tube 26, 26a Slinger ring part 27, 27a through hole 28, 28a Outer cylinder part 29, 29a Cylinder cover part 30, 30a, 30b flange part 31, 31a Labyrinth seal 32, 32a Circular cover 33, 33a Connection 34 Detected surface 35, 35a Gasket part 36 Outer cover part 37, 37a, 37b, 37c, 37d, 37e, 37f sealing materials 38, 38a, 38b Core metal 39, 39a Core tube part 40, 40a Core ring 41, 41a base 42, 42a Side lip 43 Labyrinth Seal 44, 44a, 44b Grease Lip 45 Outer ring part 46 Weir 47 Labyrinth Slip 48 Labyrinth Seal 49 Groove 50 studs 100 Hub unit bearing 101 outer ring 102 Hub 103 Annular Space 104 Combination Seal Ring 105 Slinger 106 Seal ring 107 Slinger tube 108 Slinger circular ring 109 Tapered section 110 Core 111 Sealing material 112a, 112b Side lip 113 Outer Lip

Claims

1. an outer ring having a plurality of rows of outer ring raceways on its inner circumferential surface; a hub having a plurality of rows of inner ring raceways on its outer circumferential surface; a plurality of rolling elements disposed between the plurality of rows of outer ring raceways and the plurality of rows of inner ring raceways; a combination seal ring that closes an opening on one axial side of an annular space that exists between an inner peripheral surface of the outer ring and an outer peripheral surface of the hub; Equipped with The combination seal ring includes a slinger and a seal ring including a seal material having only a side lip as a sliding contact lip that causes a tip portion of the seal material to be in sliding contact with the slinger, The slinger comprises a metal slinger body and a slinger seal member made of an elastic material and fixed to the slinger body; The slinger body includes a slinger cylindrical portion fitted onto the hub, and a slinger ring portion extending radially outward from one axial end of the slinger cylindrical portion, The slinger seal material includes a tube cover portion that covers the outer peripheral surface of the slinger tube portion, and a flange portion that extends radially outward from the other axial end of the tube cover portion, is located on the other axial side of the radially inner end of the seal ring, and has an outer diameter larger than the inner diameter of the radially inner end of the seal ring. Hub unit bearing.

2. The slinger ring portion has a through hole passing through in the axial direction, 2. The hub unit bearing of claim 1, wherein the slinger seal material further comprises: a circular ring cover portion that covers one axial side surface of the slinger circular ring portion; and a connecting portion that is arranged inside the through hole and connects the cylindrical cover portion and the circular ring cover portion.

3. 2. The hub unit bearing according to claim 1, wherein said sealing material includes a grease lip having a tip end portion closely facing the outer peripheral surface of said cylindrical cover portion.

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