Hub unit bearing

Abstract

The present invention provides a hub unit bearing that prevents foreign matter from easily entering between the outer ring and the core metal of the seal ring fixed to the outer ring. [Solution] The core metal 39 of the seal ring 30 has a large diameter cylindrical core portion 42, a bent portion 43, a circular core portion 44, a small diameter cylindrical core portion 45, and a connecting portion 46. The large diameter cylindrical core portion 42 has its axial inner portion fitted onto the axial outer end of the outer ring 2 by interference fit, and its axial outer portion protrudes axially beyond the axial outer end face of the outer ring 2. The bent portion 43 bends radially outward from the axial inner end of the large diameter cylindrical core portion 42. The circular core portion 44 has its axial inner surface abutting against the axial outer end face of the outer ring 2. The small diameter cylindrical core portion 45 extends axially outward from the radial outer end of the circular core portion 44. The connecting portion 46 bends radially inward from the axial outer end of the large diameter cylindrical core portion 42 and connects to the axial outer end of the small diameter cylindrical core portion 45.

Description

【Technical Field】 【0001】 The present disclosure relates to a hub unit bearing. 【Background Art】 【0002】 A hub unit bearing used to rotatably support an automobile wheel with respect to a suspension device is used in an environment where muddy water splashes directly, so high sealing performance is required. On the other hand, the hub unit bearing is required to keep the rotational torque low in terms of reducing the fuel consumption of the automobile. 【0003】 The hub unit bearing rotatably supports a hub to which a wheel is fixed via a plurality of rolling elements inside an outer ring supported by a suspension device. A lubricant such as grease is enclosed in an annular space where the rolling elements are installed, and an opening of the annular space is closed by a sealing member. Therefore, the performance of the sealing member has a great influence on the performance such as the sealing performance and low torque required for the hub unit bearing. 【0004】 The hub unit bearing is also required to have a large moment rigidity in order to keep the camber angle of the wheel constant regardless of the moment load based on the road surface reaction force and ensure the handling stability of the automobile. For this reason, in the hub unit bearing, the rolling elements are provided with a contact angle of the back-to-back (DB) type. Further, from the aspect of improving the moment rigidity, it is preferable to make the distance between the rows of the rolling elements arranged in multiple rows as large as possible. 【0005】 FIG. 8 shows a hub unit bearing 100 having a conventional structure described in Japanese Patent Application Laid-Open No. 2019-019865. 【0006】 The hub unit bearing 100 has an outer ring 101 and a hub 102. The inner circumferential surface of the outer ring 101 is provided with a double row of outer ring raceways 103. The outer circumferential surface of the hub 102 is provided with a double row of inner ring raceways 104. Multiple rolling elements 105 are arranged to roll freely between the double row of outer ring raceways 103 and the double row of inner ring raceways 104, one in each row. The axially outer opening of the annular space 106 that exists between the inner circumferential surface of the outer ring 101 and the outer circumferential surface of the hub 102 is sealed by a combination seal ring 107, which is a sealing member. 【0007】 The combination seal ring 107 includes a slinger 108 and a seal ring 109. 【0008】 The slinger 108 is fixed to the hub 102. 【0009】 The seal ring 109 is fixed to the outer ring 101. The seal ring 109 has a core metal 110 and a sealing material 111 bonded to the core metal 110. 【0010】 The core metal 110 has a roughly L-shaped cross-section and consists of a core metal cylindrical portion 112 that is fitted and fixed to the axially outer end of the outer ring 101, and a core metal ring portion 113 that bends at roughly a right angle radially inward from the axially outer end of the core metal cylindrical portion 112, and whose axially inner surface abuts against the axially outer end face of the outer ring 101. 【0011】 The sealing material 111 has sealing lips 114a and 114b, each with its tip in sliding contact with the surface of the slinger 108. 【0012】 In conventional hub unit bearings 100, the core metal 110 constituting the seal ring 109 is externally fitted and fixed to the axially outer end of the outer ring 101. Compared to the case where the core metal is internally fitted and fixed to the axially outer end of the outer ring, it becomes possible to position the axially outer rolling elements 105 further axially outward. As a result, the distance between rows of rolling elements 105 arranged in double rows can be increased, making it easier to ensure moment rigidity. [Prior art documents] [Patent Documents] 【0013】 [Patent Document 1] Japanese Patent Publication No. 2019-019865 [Overview of the Initiative] [Problems that the invention aims to solve] 【0014】 In the conventional hub unit bearing 100 described in Japanese Patent Publication No. 2019-019865, the core metal 110 constituting the seal ring 109 has a substantially L-shaped cross-section, and the core metal cylindrical portion 112 is fitted onto the axially outer end of the outer ring 101 by interference fit with the axially inner surface of the core metal ring portion 113 abutting against the axially outer end face of the outer ring 101. 【0015】 The rigidity of the core cylinder portion 112 is higher in the axial outer portion closer to the core ring portion 113 than in the axial inner portion further away from the core ring portion 113, due to the presence of the core ring portion 113. Therefore, of the core cylinder portion 112 that constitutes the core 110, the axial outer portion closer to the core ring portion 113 has a higher fitting force with respect to the outer ring 101, while the axial inner portion further away from the core ring portion 113 has a lower fitting force with respect to the outer ring 101. In other words, the fitting force at the entrance side between the inner circumferential surface of the core cylinder portion 112 and the outer circumferential surface of the outer ring 101 is lower. As a result, foreign matter such as muddy water can easily enter between the inner circumferential surface of the core cylinder portion 112 and the outer circumferential surface of the outer ring 101. Furthermore, if rust occurs on the core cylinder portion 112, the fitting force of the seal ring 109 with respect to the outer ring 102 will decrease, potentially reducing the sealing performance of the combined seal ring 107. 【0016】 The present disclosure aims to provide a hub unit bearing in which foreign matter is less likely to enter between the outer ring and the core metal of the seal ring fitted and fixed to the outer ring. [Means for solving the problem] 【0017】 A hub unit bearing according to one aspect of the present disclosure comprises an outer ring, a hub, a plurality of rolling elements, and a combination seal ring. The outer ring has a double row of outer ring raceways on its inner circumferential surface. The hub has a double row of inner ring raceways on its outer surface. The plurality of rolling elements are arranged to be able to roll freely between the double row of outer ring raceways and the double row of inner ring raceways. The aforementioned combination seal ring closes the axially outer opening of the annular space that exists between the inner circumferential surface of the outer ring and the outer circumferential surface of the hub. 【0018】 The aforementioned combination seal ring comprises a slinger fixed to the hub and a seal ring fixed to the outer ring. 【0019】 The slinger has a ring-shaped slinger plate portion. 【0020】 The sealing ring comprises a core metal and a sealing material including a side lip that slides against the slinger vertical plate portion at its tip. 【0021】 The core metal comprises a large-diameter cylindrical portion, a bent portion, a circular ring portion, a small-diameter cylindrical portion, and a connecting portion. The large-diameter cylindrical core portion is fitted and fixed to the outer ring's outer end by an interlocking fit at its axial inner end, and its axial outer end protrudes axially outward beyond the outer ring's outer end face. The bent portion is bent radially outward from the axially inward end of the large-diameter cylindrical portion of the core metal. The core ring portion has its axially inner surface abutting against the axially outer end surface of the outer ring. The small-diameter cylindrical portion of the core extends axially outward from the radially outer end of the ring portion of the core. The connecting portion bends radially inward from the axially outer end of the large-diameter cylindrical portion of the core metal and is connected to the axially outer end of the small-diameter cylindrical portion of the core metal. The aforementioned connecting portion is positioned axially outward from the slinger plate portion. 【0022】 In the hub unit bearing according to one aspect of the present disclosure, the connecting portion has an annular shape, and the large-diameter core metal cylinder portion and the small-diameter core metal cylinder portion can be arranged at a distance in the radial direction. The large-diameter core metal cylinder portion can be provided with a through hole in a portion that protrudes axially outside from the end surface on the axially outer side of the outer ring. 【0023】 In the hub unit bearing according to one aspect of the present disclosure, the slinger can have a slinger large-diameter cylinder portion that extends from the radially outer end portion of the slinger upright plate portion toward the axially inner side and is arranged on the radially inner side of the small-diameter core metal cylinder portion. 【Advantages of the Invention】 【0024】 According to the hub unit bearing of one aspect of the present disclosure, it is difficult for foreign matter to enter between the outer ring and the core metal of the seal ring externally fitted and fixed to the outer ring. 【Brief Description of the Drawings】 【0025】 [Figure 1] FIG. 1 is a cross-sectional view showing a hub unit bearing of the first example of the embodiment of the present disclosure. [Figure 2] FIG. 2 is an enlarged view of part X in FIG. 1. [Figure 3] FIG. 3 is a view corresponding to FIG. 2 for the second example of the embodiment of the present disclosure. [Figure 4] FIG. 4 is a view corresponding to FIG. 2 for the third example of the embodiment of the present disclosure. [Figure 5] FIG. 5 is a view corresponding to FIG. 2 for the fourth example of the embodiment of the present disclosure. [Figure 6] FIG. 6 is a view corresponding to FIG. 2 for the fifth example of the embodiment of the present disclosure. [Figure 7] FIG. 7 is a view corresponding to FIG. 2 for the sixth example of the embodiment of the present disclosure. [Figure 8] FIG. 8 is a partially enlarged cross-sectional view of a hub unit bearing having a conventional structure. [Modes for carrying out the invention] 【0026】 [Example 1] A first example of an embodiment of this disclosure will be described with reference to Figures 1 and 2. 【0027】 [Overall structure of the hub unit bearing] The hub unit bearing 1 comprises an outer ring 2, a hub 3, a plurality of rolling elements 4a, 4b, and a combination seal ring 5. The hub unit bearing 1 has an inner ring rotation type structure. 【0028】 The hub unit bearing 1 in this example is a so-called third-generation hub unit bearing for drive wheels. However, one embodiment of the hub unit bearing of this disclosure can also be applied to hub unit bearings for driven wheels, or so-called 2.5-generation hub unit bearings which are formed by combining a hub spindle with a first-generation, second-generation, and second-generation inner-ring rotating hub unit bearing, etc. 【0029】 In the following description, with respect to the hub unit bearing 1, the axial, radial, and circumferential directions refer to the axial, radial, and circumferential directions of the outer ring 2 unless otherwise specified. The axial, radial, and circumferential directions of the outer ring 2 coincide with the axial, radial, and circumferential directions of the hub 3. Furthermore, the axial outer side 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 axial inner side refers to the center side in the width direction of the vehicle when the hub unit bearing 1 is assembled to the vehicle. 【0030】 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 double rows of outer ring raceways 6a and 6b on its inner circumferential surface. 【0031】 In this example, in order to increase the moment stiffness of the hub unit bearing 1, the outer ring raceway 6a on the axial side is provided at the axially outer end of the inner circumferential surface of the outer ring 2. 【0032】 Each of the outer ring raceways 6a and 6b has a generatrix shape corresponding to the shape of the multiple rolling elements 4a and 4b. When the multiple rolling elements 4a and 4b are composed of balls, each of the outer ring raceways 6a and 6b has an arc-shaped generatrix, and when the multiple rolling elements 4a and 4b are composed of cone-shaped rollers, the outer ring raceways 6a and 6b have a linear generatrix shape inclined with respect to the central axis of the outer ring 2. In this example, since the multiple rolling elements 4a and 4b are composed of balls, each of the outer ring raceways 6a and 6b has an arc-shaped generatrix. 【0033】 In this example, the outer ring 2 has a stationary flange 7 projecting radially outward from its axial middle section. The stationary flange 7 has multiple flange-side support holes 8 that penetrate axially at multiple circumferential locations in its radial middle section. The outer ring 2 is supported and fixed to the knuckle by inserting support bolts (not shown) through one of the support holes (flange-side support holes) provided in the knuckle of the suspension device and screwing them into the other support hole. 【0034】 The outer ring 2 has a cylindrical fitting surface portion 10 at the axially outer end of its outer circumference. The fitting surface portion 10 and the axially outer outer ring raceway 6a are positioned to overlap radially. The outer ring 2 has a stepped portion 11 facing axially outward at the axially inner end of the fitting surface portion 10. The fitting surface portion 10 and the axially outer end face of the outer ring 2 are connected via a chamfered portion 12. The axially outer end face of the outer ring 2 is composed of a flat surface perpendicular to the central axis of the outer ring 2. 【0035】 The hub 3 is positioned radially inward of the outer ring 2 and coaxially with the outer ring 2. The hub 3 has double rows of inner ring raceways 9a and 9b on its outer circumferential surface. 【0036】 Each of the inner ring raceways 9a and 9b has a generatrix shape corresponding to the shape of the multiple rolling elements 4a and 4b. When the multiple rolling elements 4a and 4b are composed of balls, each of the inner ring raceways 9a and 9b has an arc-shaped generatrix, and when the multiple rolling elements 4a and 4b are composed of cone-shaped rollers, the inner ring raceways 9a and 9b have a linear generatrix shape inclined with respect to the central axis of the outer ring 2. In this example, since the multiple rolling elements 4a and 4b are composed of balls, each of the inner ring raceways 9a and 9b has an arc-shaped generatrix. 【0037】 In this example, the hub 3 has a rotating flange 13 that protrudes radially outward on the portion that protrudes axially outward from the outer ring 2, and a cylindrical pilot portion 14 at the axially outward end. 【0038】 The rotating flange 13 has mounting holes 15 that penetrate axially at multiple locations in the circumferential direction in the radially intermediate portion. Each of the mounting holes 15 is either a press-fit hole or a threaded hole. 【0039】 If each of the mounting holes 15 is a press-fit hole, a stud 16 is press-fitted into each of the mounting holes 15 from the axially inward side. Braking rotating bodies such as brake discs and wheel hubs are connected and fixed to the rotating flange 13 by inserting a pilot portion 14 through a central hole provided in the center of each, and inserting studs 16 through through holes provided at multiple locations in the circumferential direction in the radial middle of each, and screwing a hub nut (not shown) onto the tip of the stud 16. 【0040】 If each of the mounting holes 15 is a threaded hole, the braking rotating body such as a brake disc and the wheel of the wheel are connected and fixed to the rotating flange 13 by inserting the pilot portion 14 through the central hole provided in the center of each and screwing hub bolts, which are inserted through through holes provided at multiple locations in the circumferential direction in the radial middle of each, into the mounting holes 15 from the axial outside. 【0041】 In this example, each of the mounting holes 15 is a press-fit hole, and a stud 16 is press-fitted into each of the mounting holes 15. 【0042】 In this example, the hub unit bearing 1 is a hub unit bearing for a drive wheel, and therefore the hub 3 has a spline hole 17 in its radial center that penetrates the hub 3 axially. The tip of the drive shaft, which is driven by an engine or electric motor, is spline-engaged into the spline hole 17. When the automobile is running, the hub 3 is rotated by the drive shaft, and the wheel and braking rotating body, which are coupled and fixed to the rotating flange 13 of the hub 3, are rotated. 【0043】 Furthermore, when a hub unit bearing according to one aspect of this disclosure is applied to a hub unit bearing for a driven wheel, the hub can be constructed to be solid. 【0044】 The hub 3 comprises an inner ring 18 and a hub wheel 19. 【0045】 The inner ring 18 is constructed in a cylindrical shape from a hard metal such as bearing steel. 【0046】 The inner ring 18 has an inner ring raceway 9b, which is the axially innermost of multiple rows of inner ring raceways 9a and 9b, in the axial middle portion of its outer surface. 【0047】 The hub wheel 19 has multiple rows of inner ring raceways 9a, 9b in the axial middle portion of its outer circumference, with the inner ring raceway 9a being the outermost in the axial direction. 【0048】 The hub wheel 19 has a rotating flange 13 in a portion located axially outward from the inner ring raceway 9a on the axially outward side, and a pilot portion 14 at its axially outward end. 【0049】 Furthermore, the hub wheel 19 has a fitting shaft portion 20 located axially inward of the inner ring raceway 9a on the axially outer side, having an outer diameter smaller than the outer diameter of the portion adjacent to it on the axially outer side. The hub wheel 19 has a stepped surface 21 that connects the portion of its outer circumferential surface adjacent to the axially inward side of the inner ring raceway 9a on the axially outer side with the outer circumferential surface of the fitting shaft portion 20 and faces axially inward. The hub wheel 19 further has a crimping portion 22 that bends radially outward from the axially inward end of the fitting shaft portion 20 and presses against the axially inward end face of the inner ring 18. 【0050】 Therefore, the hub 3 in this example is constructed by fitting the inner ring 18 onto the fitting shaft portion 20 of the hub ring 19, and then clamping the inner ring 18 from both axial sides between the stepped surface 21 and the crimping portion 22 to connect and fix the inner ring 18 and the hub ring 19. 【0051】 The hub can also be constructed by omitting the crimping portion from the axially inner end of the mating shaft portion, and by sandwiching the inner ring from both axial sides between the stepped surface and the outer ring for constant velocity joint, thereby connecting and fixing the inner ring and the hub ring. 【0052】 The hub ring 19 has a shoulder portion 23 adjacent to the axially outer portion of the inner ring raceway 9a on the axially outer side. The shoulder portion 23 has a cylindrical surface portion 24 on the axially outer portion of its outer circumference and an inclined surface portion 25 on the axially inner portion. The outer diameter of the inclined surface portion 25 decreases as it moves axially inward. In this example, the cylindrical surface portion 24 is located axially outward from the axially outer end face of the outer ring 2. 【0053】 In this example, the hub unit bearing 1 is a so-called third-generation hub unit bearing, and therefore the hub ring 19 is integrally constructed from a hard metal such as medium carbon steel. However, for example, when applying a hub unit bearing according to one aspect of this disclosure to a so-called 2.5-generation hub unit bearing, the hub ring can also be constructed by combining a hub spindle having a rotating flange and a pilot portion with another inner ring having an inner ring raceway on its outer circumference that is axially outward. 【0054】 The rolling elements 4a and 4b are arranged to roll freely in multiples for each row between the double-row outer ring raceways 6a and 6b and the double-row inner ring raceways 9a and 9b. In this example, the rolling elements 4a and 4b are arranged to roll freely at equal intervals in the circumferential direction, held by cages 26a and 26b, in multiples for each row between the double-row outer ring raceways 6a and 6b and the double-row inner ring raceways 9a and 9b. To increase the moment rigidity, the hub unit bearing 1 is provided with a back-to-back (DB) contact angle for the rolling elements 4a and 4b arranged in double rows. 【0055】 The rolling elements 4a and 4b are made of hard metals such as bearing steel, or ceramics. 【0056】 The rolling elements 4a and 4b are composed of balls or tapered rollers. In this example, the rolling elements 4a and 4b are composed of balls. 【0057】 The hub unit bearing 1 in 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, one aspect of the hub unit bearing of this 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. 【0058】 The combination seal ring 5 closes the axially outer opening of the annular space 27, which is an internal space located between the inner circumferential surface of the outer ring 2 and the outer circumferential surface of the hub 3. 【0059】 The hub unit bearing 1 in this example further includes a sealing device 28 that closes the axially inner opening of the annular space 27. The sealing device 28 is not limited to this, but can be composed of, for example, a combination sealing ring comprising a mandrel and a sealing ring, or a bearing cap. 【0060】 The combination seal ring 5 and the seal device 28 prevent leakage of grease (not shown) sealed in the annular space 27, and also prevent foreign matter such as muddy water from entering the annular space 27. 【0061】 [Structure of combination sealing rings] The combined seal ring 5 comprises a slinger 29 and a seal ring 30. The slinger 29 is fixed to the hub 3 and rotates during use. In contrast, the seal ring 30 is fixed to the outer ring 2 and does not rotate even during use. 【0062】 <Slinga> The slinger 29 has a ring-shaped slinger plate portion 31. 【0063】 In this example, the slinger 29 is composed of a metal slinger body 32 and an elastic slinger seal material 33 that is bonded and fixed to the slinger body 32. The slinger 29 is constructed by bonding and fixing the slinger seal material 33 to the slinger body 32 by vulcanization adhesive. However, when implementing a hub unit bearing according to one embodiment of this disclosure, the slinger may consist only of the slinger body. 【0064】 The slinger body 32 is constructed in an annular shape by bending a metal sheet, such as a stainless steel sheet or a cold-rolled steel sheet treated for rust prevention. The slinger body 32 comprises a slinger vertical plate portion 31 and a slinger fitting cylinder portion 34. In this example, the slinger body 32 has a roughly L-shaped cross-section. 【0065】 The slinger fitting cylinder portion 34 has a substantially cylindrical shape and is fitted onto the hub 3. In this example, the slinger fitting cylinder portion 34 is fitted and fixed to the shoulder portion 23 of the hub ring 19 that constitutes the hub 3 by interference fit. 【0066】 In this example, the slinger fitting cylinder portion 34 has a cylindrical portion 35 and a locking portion 36. The cylindrical portion 35 has a cylindrical shape and is fitted by interference fit onto a cylindrical surface portion 24 provided on the axially outer part of the outer circumferential surface of the shoulder portion 23 of the hub wheel 19. The locking portion 36 has a conical shape and is fitted onto an inclined surface portion 25 provided on the axially inner part of the outer circumferential surface of the shoulder portion 23 of the hub wheel 19. The locking portion 36 contacts (engages) with the inclined surface portion 25 to position the slinger 29 in the axial direction relative to the hub 3. 【0067】 In the implementation of a hub unit bearing according to one aspect of this disclosure, the slinger fitting cylinder portion may consist only of a cylindrical portion. Furthermore, if the slinger fitting cylinder portion consists of a cylindrical portion and a locking portion, the shape of the locking portion is not limited to a conical shape, but may be configured in other shapes such as an inward flange shape or a comb-tooth shape. 【0068】 The slinger upright plate portion 31 extends radially outward from the axially outer end of the slinger fitting cylinder portion 34. The slinger upright plate portion 31 is bent in a direction approximately perpendicular to the slinger fitting cylinder portion 34. The axially inner surface of the slinger upright plate portion 31, except for the radially inner end, is composed of a flat surface that is approximately perpendicular to the central axis of the slinger body 32. 【0069】 The outer diameter of the slinger plate portion 31 is smaller than the outer diameter of the axially outer end of the outer ring 2, and larger than the inner diameter of the axially outer end of the outer ring 2. For this reason, the slinger plate portion 31 is positioned axially opposite to the axially outer end face of the outer ring. The slinger plate portion 31 is positioned between the axially outer end face of the outer ring 2 and the axially inner surface of the rotating flange 13 provided on the hub ring 19. 【0070】 The slinger seal material 33 is made of an elastic material such as an elastomer like rubber and covers the surface of the slinger 29. In this example, the slinger seal material 33 covers the entire circumference of the radially inner end to the radially middle portion of the axially outer surface of the slinger vertical plate portion 31. 【0071】 The slinger seal material 33 has a gasket portion 37 at its radially inward end, the tip of which elastically contacts the outer circumferential surface of the hub wheel 19. The gasket portion 37 prevents foreign matter entering from the external space from entering between the inner circumferential surface of the slinger fitting cylinder portion 34 and the outer circumferential surface of the shoulder portion 23 of the hub wheel 19. The slinger seal material 33 has an annular projection 38 radially outward from the gasket portion 37. This prevents the slingers 29 from sticking together when stacked and also provides a labyrinth effect on the gasket portion 37. Figure 2 shows the shape of the gasket portion 37 in its free state. 【0072】 <Seal Ring> The seal ring 30 includes a core metal 39 and a sealing material 41 which includes a side lip 40 that slides against the slinger vertical plate portion 31 at its tip. 【0073】 The core metal 39 has a large diameter cylindrical portion 42, a bent portion 43, a circular ring portion 44, a small diameter cylindrical portion 45, and a connecting portion 46. In this example, the core metal 39 has a roughly T-shaped cross-section. 【0074】 The core metal 39 is formed into a ring shape by bending a metal sheet, such as a cold-rolled steel sheet. 【0075】 The core metal large diameter cylindrical portion 42 has a substantially cylindrical shape, and its axial inner portion is fitted and fixed to the axial outer end of the outer ring 2 by interference fit, and its axial outer portion protrudes axially outward from the axial outer end face of the outer ring 2. In this example, the axial inner half of the core metal large diameter cylindrical portion 42 is fitted and fixed to the fitting surface portion 10 of the outer ring 2 by interference fit, and its axial outer half protrudes axially outward from the axial outer end face of the outer ring 2. 【0076】 The bent portion 43 is bent radially outward from the axially inward end of the large-diameter cylindrical portion 42 of the mandrel. In this example, the bent portion 43 is bent approximately perpendicular to the large-diameter cylindrical portion 42 of the mandrel. The bent portion 43 is configured in an outward flange shape. A small gap is provided between the bent portion 43 and the stepped portion 11 provided on the outer circumferential surface of the outer ring 2. The radial width dimension of the bent portion 43 is not limited to this, but is approximately 2 to 3 times the thickness of the mandrel 39. 【0077】 When implementing a hub unit bearing according to one aspect of this disclosure, the shape of the bent portion is not limited to an outward flange shape, but can be configured in other shapes such as a substantially transverse U-shape or a crank shape, as long as it includes a portion that is bent radially outward from the axially inward end of the large-diameter cylindrical core. 【0078】 The core ring portion 44 has its axially inner surface abutting the axially outer end face of the outer ring 2. This ensures the axial positioning of the core 39 relative to the outer ring 2. In this example, the core ring portion 44 has a ring shape. In this example, the core ring portion 44 has an inner diameter that is slightly smaller than the inner diameter of the portion of the inner circumferential surface of the outer ring 2 that is axially outward from the outer ring raceway 6a on the axial side, enabling the vulcanization molding of the gasket 50 described later. 【0079】 The small diameter cylindrical portion 45 of the mandrel extends axially outward from the radially outer end of the mandrel ring portion 44. In this example, the small diameter cylindrical portion 45 has a substantially cylindrical shape. The small diameter cylindrical portion 45 is positioned so as to overlap radially with the axially outer half of the large diameter cylindrical portion 42 of the mandrel. The axial dimension of the small diameter cylindrical portion 45 is approximately the same as the axial dimension of the portion of the large diameter cylindrical portion 42 that protrudes axially outward from the axially outer end face of the outer ring 2. 【0080】 With the combination seal ring 5 installed, the axially outer end of the inner circumferential surface of the core metal small diameter cylindrical portion 45 and the outer circumferential surface of the slinger upright plate portion 31 that constitutes the slinger 29 are in close proximity and facing each other along the entire circumference. As a result, a labyrinth seal 47 is formed between the inner circumferential surface of the core metal small diameter cylindrical portion 45 and the outer circumferential surface of the slinger upright plate portion 31. 【0081】 The connecting portion 46 bends radially inward from the axially outer end of the large-diameter cylindrical portion 42 of the mandrel and connects to the axially outer end of the small-diameter cylindrical portion 45 of the mandrel. In this example, the connecting portion 46 bends radially inward from the axially outer end of the large-diameter cylindrical portion 42 of the mandrel and is folded back axially inward, forming a roughly transverse U-shape in cross-section. In other words, the connecting portion 46 is composed of a bent portion that has been bent 180 degrees. The radial dimension of the connecting portion 46 is approximately twice the thickness of the mandrel 39. Therefore, the inner circumferential surface of the axially outer half of the large-diameter cylindrical portion 42 of the mandrel and the outer circumferential surface of the small-diameter cylindrical portion 45 of the mandrel are in surface contact over the entire circumference. 【0082】 In this example, with the combination seal ring 5 installed, the connecting portion 46 is located axially outward from the slinger vertical plate portion 31 that constitutes the slinger 29. Furthermore, the axially outward end of the connecting portion 46 and the axially inward surface of the rotating flange 13 are in close proximity to each other around the entire circumference. As a result, a labyrinth seal 54 is formed between the axially outward end of the connecting portion 46 and the axially inward surface of the rotating flange 13. The axial distance A of the gap between the axially outward end of the connecting portion 46 and the axially inward surface of the rotating flange 13 is approximately 1 / 10 to 1 / 5 of the axial distance B between the axially outward end face of the outer ring 2 and the axially inward surface of the rotating flange 13. 【0083】 The sealing material 41 is made of an elastic material such as an elastomer like rubber, and is bonded and fixed to the core metal 39 by vulcanization adhesive or the like. 【0084】 The sealing material 41 has a side lip 40, a sealing base 48 that covers the surface of the core metal 39, and a grease lip 49. 【0085】 The seal base 48 is bonded and fixed to the surface of the mandrel 39. In this example, the seal base 48 covers the mandrel 39, specifically the area from the axial middle to the radially inward end of the axially outer surface of the mandrel ring portion 44, the inner circumferential surface, and the radially inward end of the axially inner surface. 【0086】 In this example, the seal base 48 is equipped with a gasket 50 at the radially outer end of the portion that covers the axially inner surface of the core ring portion 44. The gasket 50 is pressed against the axially outer end of the inner circumferential surface of the outer ring 2. Figure 2 shows the shape of the gasket 50 in its free state. 【0087】 The side lip 40 is a so-called mud lip, and its base end is connected to the portion of the seal base 48 that covers the axial outer surface of the core ring portion 44, and its tip is in sliding contact with the axial inner surface of the slinger upright plate portion 31. In this example, the side lip 40 has a conical shape and extends radially outward as it moves axially outward. The side lip 40 prevents foreign matter such as mud from entering the annular space 27 from the external space. Figure 2 shows the shape of the side lip 40 in its free state. 【0088】 In this example, the sealing material 41 has only one side lip 40. However, in a hub unit bearing according to one aspect of the present disclosure, the sealing material may have multiple side lips. 【0089】 The grease slip 49 has its base end connected to the portion of the seal base 48 that covers the inner circumferential surface of the core ring portion 44, and its tip is in light contact with the outer circumferential surface of the slinger fitting cylinder portion 34. In this example, the tip of the grease slip 49 is in contact with the outer circumferential surface of the locking portion 36 that constitutes the slinger fitting cylinder portion 34. The grease slip 49 has a substantially conical shape and extends in the direction axially inward as it moves radially inward. The grease slip 49 prevents the grease sealed in the annular space 27 from leaking into the external space. 【0090】 When implementing a hub unit bearing according to one aspect of the present disclosure, the tip of the grease slip can be brought into sliding contact with the outer circumferential surface of the cylindrical portion constituting the slinger fitting cylinder, or it can be brought into sliding contact with the outer circumferential surface of the hub. 【0091】 In this example of the hub unit bearing 1, foreign matter is less likely to enter between the outer ring 2 and the core metal 39 of the seal ring 30 which is fitted and fixed to the outer ring 2. 【0092】 The large-diameter cylindrical core portion 42 constituting the core metal 39 has a bent portion 43 that is bent radially outward at its axially inner end, and a connecting portion 46 that is bent radially inward at its axially outer end. Therefore, the rigidity of the large-diameter cylindrical core portion 42 is increased at both axial ends of the large-diameter cylindrical core portion 42 due to the presence of the bent portion 43 and the connecting portion 46. When the seal ring 30 is mounted on the outer ring 2, the axially inner portion of the large-diameter cylindrical core portion 42 is externally fitted and fixed to the axially outer end of the outer ring 2 by interference fit, and its axially outer portion protrudes axially outward from the axially outer end face of the outer ring 2. As a result, the connecting portion 46 and the portion of the core metal large-diameter cylindrical portion 42 that is fitted and fixed to the outer ring 2 are separated in the axial direction. Therefore, the presence of the connecting portion 46 reduces the influence of the fitting force on the portion of the core metal large-diameter cylindrical portion 42 that is fitted and fixed to the outer ring 2. On the other hand, the fitting force of the portion of the core metal large-diameter cylindrical portion 42 that is fitted and fixed to the outer ring 2 is higher in the axial direction on the inner portion than on the axial direction on the outer portion due to the influence of the bent portion 43. Therefore, the fitting force on the inlet side between the inner circumferential surface of the core metal large-diameter cylindrical portion 42 and the fitting surface portion 10 of the outer ring 2 can be increased. As a result, it becomes more difficult for foreign matter such as muddy water to enter between the inner circumferential surface of the core metal large-diameter cylindrical portion 42 and the fitting surface portion 10 of the outer ring 2. Furthermore, a decrease in the fitting force of the seal ring 30 on the outer ring 2 can be prevented, and a decrease in the sealing performance of the combined seal ring 5 can be prevented. 【0093】 In this example, the inner half of the mandrel's large diameter cylindrical portion 42 is fitted and fixed to the outer ring 2 by an interlocking fit, and the outer half of the mandrel's large diameter cylindrical portion 42 protrudes axially outward from the outer ring 2's outer end face. As a result, the distance from the connecting portion 46 to the portion of the mandrel's large diameter cylindrical portion 42 that is fitted and fixed to the outer ring 2 becomes large. Therefore, the fitting force of the portion of the mandrel's large diameter cylindrical portion 42 that is fitted and fixed to the outer ring 2 is hardly affected by the connecting portion 46. 【0094】 In this example, the connecting portion 46, which is bent radially inward from the axially outer end of the large-diameter cylindrical core portion 42, is positioned axially outward from the slinger upright plate portion 31 that constitutes the slinger 29. Therefore, the side lip 40 can be covered radially outward by the large-diameter cylindrical core portion 42. Consequently, foreign matter such as muddy water can be prevented from splashing directly onto the side lip 40, improving the durability of the side lip 40. Furthermore, since a labyrinth seal 54 is formed between the axially outer end of the connecting portion 46 and the axially inner surface of the rotating flange 13, the sealing performance of the combined seal ring 5 can be improved. 【0095】 The bent portion 43 that makes up the core metal 39 can also block foreign matter such as muddy water that moves axially outward along the outer surface of the outer ring 2. This improves the sealing performance of the combined seal ring 5. 【0096】 In this example, since the connecting portion 46 is configured with a roughly horizontal U-shaped cross-section, the inner circumferential surface of the large-diameter cylindrical core portion 42 and the outer circumferential surface of the small-diameter cylindrical core portion 45 are in surface contact over the entire circumference. As a result, the portion of the large-diameter cylindrical core portion 42 that protrudes axially outward from the axially outer end face of the outer ring 2 can be supported from the radially inward by the small-diameter cylindrical core portion 45, thereby increasing the strength of the portion of the large-diameter cylindrical core portion 42 that protrudes axially outward from the axially outer end face of the outer ring 2. 【0097】 In this example, a labyrinth seal 47 is formed between the inner surface of the core metal small diameter cylindrical portion 45 and the outer surface of the slinger upright plate portion 31. This prevents foreign matter such as muddy water from entering the space between the slinger 29 and the seal ring 30 and adhering to the side lip 40. 【0098】 In this example, the sealing material 41 constituting the seal ring 30 is equipped with a grease lip 49 whose tip is in contact with the outer circumferential surface of the slinger fitting cylinder portion 34, thereby preventing the grease sealed in the annular space 27 from leaking into the outside space. 【0099】 In this example, since the sealing material 41 constituting the seal ring 30 includes a gasket 50 pressed against the axially outer end of the inner circumferential surface of the outer ring 2, even if foreign matter enters between the inner circumferential surface of the core metal large diameter cylindrical portion 42 and the fitting surface portion 10 of the outer ring 2 and moves to the space between the axially inner surface of the core metal circular ring portion 44 and the axially outer end face of the outer ring 2, it is possible to prevent the foreign matter from entering the annular space 27. 【0100】 [Example 2] A second example of the embodiment of this disclosure will be explained with reference to Figure 3. 【0101】 This example is a modification of the first example, and only the structure of the slinger body 32a constituting the slinger 29a differs from the structure of the slinger body 32 in the first example. 【0102】 In this example, the slinger body 32a further comprises a slinger large-diameter cylindrical portion 51 in addition to the slinger upright plate portion 31 and the slinger fitting cylindrical portion 34. The slinger body 32a has a roughly horizontal U-shaped cross-section. 【0103】 The slinger large-diameter cylindrical portion 51 extends axially inward from the radially outer end of the slinger upright plate portion 31. The slinger large-diameter cylindrical portion 51 has a substantially cylindrical shape and is bent in a direction substantially perpendicular to the slinger upright plate portion 31. The slinger large-diameter cylindrical portion 51 is positioned radially inward of the core metal small-diameter cylindrical portion 45 and covers the side lip 40 from the radially outer side. When implementing a hub unit bearing according to one embodiment of the present disclosure, the slinger large-diameter cylindrical portion can also be configured in other shapes, such as a conical cylindrical shape or a stepped cylindrical shape. 【0104】 A labyrinth seal 47a, which extends in the axial direction, is formed between the outer circumferential surface of the large-diameter cylindrical portion 51 of the slinger and the inner circumferential surface of the small-diameter cylindrical portion 45 of the core metal. 【0105】 In this example, the large-diameter slinger section 51 also protects the side lip 40 from foreign matter such as muddy water. Since an axially long labyrinth seal 47a is provided between the outer circumferential surface of the large-diameter slinger section 51 and the inner circumferential surface of the small-diameter core metal section 45, the sealing performance of the combined seal ring 5 can be improved. 【0106】 The other components and effects of the second example are the same as those of the first example. 【0107】 [Example 3] A third example of the embodiment of this disclosure will be explained with reference to Figure 4. 【0108】 This example is a modification of the first example, and the structure of the connection portion 46a of the core metal 39a constituting the seal ring 30a is different from the structure of the connection portion 46 in the first example. 【0109】 In this example, the connecting portion 46a has a ring shape that extends radially. The connecting portion 46a is bent approximately at a right angle radially inward from the axially outer end of the large diameter cylindrical portion 42 of the mandrel. The radially outer end of the connecting portion 46a is connected to the axially outer end of the large diameter cylindrical portion 42 of the mandrel, and the radially inward end is connected to the axially outer end of the small diameter cylindrical portion 45 of the mandrel. 【0110】 In this example, the inner circumferential surface of the portion of the large-diameter cylindrical core 42 that protrudes axially outward from the axially outer end face of the outer ring 2 and the outer circumferential surface of the small-diameter cylindrical core 45 are arranged radially apart. As a result, a space 52 with a substantially square cross-section and an annular shape overall is formed between the inner circumferential surface of the large-diameter cylindrical core 42, the outer circumferential surface of the small-diameter cylindrical core 45, the axially inner surface of the connecting portion 46a, and the axially outer end face of the outer ring 2. In this example, since the small-diameter cylindrical core 45 has a cylindrical shape, the small-diameter cylindrical core 45 and the large-diameter cylindrical core 42 are arranged substantially parallel to each other. However, when implementing a hub unit bearing according to one embodiment of this disclosure, the small-diameter cylindrical core may have a conical shape. 【0111】 In this example, since the connecting portion 46a has a ring shape, the workability of the mandrel 39a can be improved. Specifically, the bending angle between the large diameter cylindrical portion 42 of the mandrel and the connecting portion 46a, and the bending angle between the small diameter cylindrical portion 45 of the mandrel and the connecting portion 46a are both approximately 90 degrees. Since the large diameter cylindrical portion 42, the connecting portion 46a, and the small diameter cylindrical portion 45 of the mandrel are formed by a two-stage bending process, the degree of processing by press working can be reduced compared to the case where the connecting portion 46, which has a bending angle of 180 degrees, is formed by a single bending process, as in the first example. This makes it possible to use a difficult-to-process material such as stainless steel for the mandrel 39a. In addition, since the labyrinth seal 54a formed between the axial outer surface of the connecting portion 46a and the axial inner surface of the rotating flange 13 can be made longer in the radial direction, the sealing performance of the combined seal ring 5 can be further improved. 【0112】 The other components and effects of the third example are the same as those of the first example. 【0113】 [Example 4] A fourth example of the embodiments of this disclosure will be explained with reference to Figure 5. 【0114】 This example is a modification of the third example, in which the large-diameter core portion 42 has a through hole 53 that extends radially through the portion that protrudes axially outward from the axially outer end face of the outer ring 2. 【0115】 In this example, through holes 53 are provided at multiple locations in the circumferential direction of the large-diameter cylindrical core portion 42. The through holes 53 are arranged at equal intervals in the circumferential direction. The through holes 53 are provided in the axial intermediate portion of the large-diameter cylindrical core portion 42 that protrudes axially outward from the axially outer end face of the outer ring 2. 【0116】 In the implementation of a hub unit bearing according to one aspect of this disclosure, the through hole may be provided at only one location in the circumferential direction of the large-diameter cylindrical portion of the mandrel. In this case, the through hole may be provided at the lower vertical end of the large-diameter cylindrical portion of the mandrel. 【0117】 In this example, the large-diameter cylindrical core portion 42 has a through hole 53 in the portion that protrudes axially outward from the axially outer end face of the outer ring 2. Therefore, even if foreign matter such as muddy water enters the space 52 between the inner circumferential surface of the large-diameter cylindrical core portion 42 and the fitting surface portion 10 of the outer ring 2, the foreign matter can be discharged to the outside space through the through hole 53. Furthermore, since pressure fluctuations in the space 52 caused by temperature changes in the space 52 can be suppressed, a decrease in the fitting force of the large-diameter cylindrical core portion 42a to the outer ring 2 can be suppressed. 【0118】 The composition and effects of the other parts of the fourth example are the same as those of the first and third examples. 【0119】 [Example 5] A fifth example of the embodiments of this disclosure will be explained with reference to Figure 6. 【0120】 The combination seal ring 5 in this example has a structure that combines the slinger 29a of the second example and the seal ring 30a of the third example. Specifically, it has a structure that combines the slinger 29a, which has a large diameter cylindrical portion 51 and a substantially horizontal U-shaped cross-section, and the seal ring 30a, which has a core metal 39a with a ring-shaped connecting portion 46a. 【0121】 In this example, the large-diameter slinger section 42 protects the side lip 40 from foreign matter such as muddy water, and also improves the workability of the core metal 39a. 【0122】 The composition and effects of the remaining parts of Example 5 are the same as those of Examples 1, 2, and 3. 【0123】 [Example 6] A sixth example of the embodiment of this disclosure will be explained with reference to Figure 7. 【0124】 The combination seal ring 5 in this example has a structure that combines the slinger 29a of the second example and the seal ring 30a of the fourth example. Specifically, it has a structure that combines the slinger 29a, which has a large diameter cylindrical portion 51 and a substantially horizontal U-shaped cross-section, and the seal ring 30a, which has a core metal 39a having a ring-shaped connecting portion 46a and a core metal large diameter cylindrical portion 42 with a through hole 53. 【0125】 In this example, the large-diameter slinger section 42 protects the side lip 40 from foreign matter such as mud and improves the workability of the core metal 39a. In addition, it allows foreign matter that has entered the space 52 through the through hole 53 to be discharged, and prevents a decrease in the fitting force of the large-diameter core metal section 42 to the outer ring 2. 【0126】 The composition and effects of the other parts of Example 6 are the same as those of Examples 1 through 4. 【0127】 The first to sixth embodiments of this disclosure can be combined as appropriate, as long as they do not create any inconsistencies. [Explanation of symbols] 【0128】 1 Hub unit bearing 2 Outer ring 3 Hubs 4a, 4b Rolling elements 5 combination sealing rings 6a, 6b Outer ring track 7. Stationary flange 8 Flange-side support holes 9a, 9b Inner ring track 10 Mating surface 11 Step section 12 Chamfered section 13 Rotating flange 14. Pilot Section 15 mounting holes 16 studs 17 Splined holes 18 Inner circle 19 Hub Wheel 20 Fitting shaft portion 21 Step surface 22 Crimping part 23 Shoulder 24 Cylindrical surface part 25 Slope section 26a, 26b retainer 27 Circular Space 28. Sealing device 29, 29a Slinger 30, 30a sealing ring 31 Slinger upright plate section 32, 32a Slinger body 33 Slinger seal material 34 Slinger fitting cylinder 35 Cylindrical section 36 Locking part 37 Gasket section 38 Annular projection 39 Mandrel 40 Side Lip 41. Sealant 42, 42a Large diameter cylindrical part of the core 43. Bent section 44 Core metal ring part 45 Core metal small diameter cylinder part 46, 46a Connection part 47, 47a Labyrinth Seal 48 Seal base 49 Grease Lip 50 Gaskets 51 Slinger large diameter cylinder section 52 Space 53 Through holes 54, 54a Labyrinth Seal 100 Hub Unit Bearings 101 Outer ring 102 Hub 103 Outer Ring Track 104 Inner track 105 Rolling element 106 Circular Space 107 Combination Seal Rings 108 Slinger 109 Seal Ring 110 Mandrel 111 Sealant 112 Core tube part 113 Core metal ring part 114a, 114b Seal Lip

Claims

[Claim 1] An outer ring having a double row of outer ring raceways on its inner circumference, A hub having double rows of inner ring raceways on its outer surface, Multiple rolling elements are arranged to roll freely between the double-row outer ring raceway and the double-row inner ring raceway, The system includes a combination seal ring that closes the axially outer opening of the annular space between the inner surface of the outer ring and the outer surface of the hub, The aforementioned combination seal ring comprises a slinger fixed to the hub and a seal ring fixed to the outer ring. The slinger has a ring-shaped slinger plate portion, The sealing ring comprises a core metal and a sealing material including a side lip that slides against the slinger plate portion at its tip. The aforementioned core metal is The axial inner portion is fitted and fixed to the axial outer end of the outer ring by interference fit, and the axial outer portion protrudes axially outward from the axial outer end face of the outer ring, forming a large diameter core metal cylinder. The bent portion of the large-diameter cylindrical core is bent radially outward from the axially inward end, The axial inner surface of the core ring portion abuts against the axial outer end face of the outer ring, A small-diameter cylindrical portion of the core metal extends axially outward from the radially outer end of the aforementioned ring portion of the core metal, A connecting portion is formed by bending radially inward from the axially outer end of the large-diameter cylindrical portion of the core metal, and connecting to the axially outer end of the small-diameter cylindrical portion of the core metal. It has, The aforementioned connecting portion is positioned axially outward from the aforementioned slinger plate portion. Hub unit bearing. [Claim 2] The aforementioned connecting portion has a ring shape, The large-diameter cylindrical portion of the core metal and the small-diameter cylindrical portion of the core metal are arranged to be separated radially. The aforementioned large-diameter cylindrical core portion has a through hole in the portion that protrudes axially outward from the axially outer end face of the outer ring. The hub unit bearing according to claim 1. [Claim 3] The hub unit bearing according to claim 1, wherein the slinger extends axially inward from the radially outer end of the slinger vertical plate portion and has a slinger large diameter cylindrical portion arranged radially inward of the core metal small diameter cylindrical portion.

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