JP2022157357A - hub unit bearing - Google Patents

Abstract

To realize a structure which can sufficiently secure fitting force applied by a slinger to a hub and maintain good sealability achieved by a seal device for a long time.SOLUTION: A slinger 26 has: a cylindrical part 28 which is fixedly fitted on a cylindrical surface part 14a of a hub 3; a side plate part 29 which bends from an axial outer end of the cylindrical part 28 to the radial outer side; and a bending part 30 which bends from an axial inner end of the cylindrical part 28 to the radial inner side over an entire periphery.SELECTED DRAWING: Figure 2

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hub unit bearing for rotatably supporting wheels and braking rotors of an automobile with respect to a suspension system.

A vehicle wheel and a braking rotator are rotatably supported with respect to a suspension system by hub unit bearings. The hub unit bearing has an outer ring having a double-row outer ring raceway on its inner peripheral surface and a double-row inner ring raceway on its outer peripheral surface, and protrudes radially outward from a portion located axially outside the outer ring. A hub having a rotating flange, and a plurality of rolling elements arranged to be free to roll between the double-row outer ring raceway and the double-row inner ring raceway.

"Outside" in the axial direction refers to the outer side of the vehicle body with the hub unit bearing assembled to the vehicle. Inside.

The hub unit bearing further includes a sealing device that closes an axially outer opening of the rolling element installation space that exists between the inner peripheral surface of the outer ring and the outer peripheral surface of the hub. Japanese Patent Application Laid-Open No. 2010-261598 (Patent Document 1) discloses a core bar that is internally fitted and fixed to the axially outer end of an outer ring, and each tip of which is attached to the outer peripheral surface of an axially intermediate portion of a hub or a rotating flange. A seal device is described which has a plurality of seal lips which are brought into sliding contact with the axial inner surface, and which is provided with a seal material which is coupled and fixed to the core bar.

Here, as described in Japanese Patent Application Laid-Open No. 2017-180599 (Patent Document 2), the portion of the outer peripheral surface of the hub with which the tip of the seal lip slides is provided with a formed grinding wheel (rotating wheel). ) is used for finishing. When finishing the outer peripheral surface of the hub using a formed grinding wheel, in order to secure the pressing force of the grinding wheel against the outer peripheral surface of the hub, the central axes of the hub and the magnetic chuck should be eccentric. support as it is. Therefore, of the outer peripheral surface of the hub, wear is likely to occur on the shoe that supports the portion on the radially opposite side of the portion against which the grinding wheel is pressed. prone to inconsistencies. Therefore, the position of the grinding surface of the grinding wheel with respect to the axial inner surface of the rotary flange changes in the radial direction of the hub, and a logarithmic spiral (spiral) grinding streak is formed on the axial inner surface of the rotary flange. There is a possibility that

When the logarithmic spiral grinding streaks are formed on the axial inner surface of the rotary flange, the tip of the seal lip of the seal ring penetrates deeply into the recessed portion of the grinding streaks, and when the hub rotates, it moves radially. There is a possibility that the reciprocating motion will vibrate and generate an abnormal noise called seal squeal.

On the other hand, in Japanese Patent Laying-Open No. 2017-207124 (Patent Document 3), a slinger having an L-shaped cross section is fitted to the outer peripheral surface of the axially intermediate portion of the hub, and the slinger is attached to the seal body. A seal device is described in which the tip of the provided seal lip is brought into sliding contact. Furthermore, in the sealing device described in Japanese Patent Application Laid-Open No. 2017-207124, slits are formed at a plurality of locations in the circumferential direction of the tubular portion (tubular portion) of the slinger, and the tip of the portion between slits adjacent in the circumferential direction A claw portion formed by bending the portion radially inward is engaged with a recess formed in the outer peripheral surface of the hub. This prevents axial inward relative movement (walkout) of the slinger with respect to the hub.

JP 2010-261598 A JP 2017-180599 A JP 2017-207124 A Japanese Unexamined Patent Application Publication No. 2005-3111

In the conventional structure described in Japanese Patent Application Laid-Open No. 2017-207124, slits are formed at a plurality of locations in the circumferential direction of the cylindrical portion (cylinder portion) of the slinger, the slits opening toward the inner end portion in the axial direction. Therefore, the rigidity of the tubular portion in the circumferential direction is lowered, and it becomes difficult to fix the slinger to the hub by fitting. Further, the outer peripheral surface of the cylindrical portion is formed as a lip sliding contact surface with which the tip of the seal lip is slidably contacted, or the tip of the seal lip is closely opposed to the tip of the seal lip and the tubular shape. A labyrinth slip cannot be configured between the outer peripheral surface of the part. As a result, it may become difficult to maintain good sealing performance of the sealing device for a long period of time.

Japanese Patent Application Laid-Open No. 2005-3111 (Patent Document 4) describes a structure using tapered rollers as rolling elements. A hub unit bearing is disclosed in which the angle formed between the axial inner surface and the outer peripheral surface of the flange is an obtuse angle. As a result, when the hub is subjected to high-frequency heat treatment, it is possible to prevent the occurrence of damage such as cracks due to local overheating of the connecting portion between the axial inner surface and the outer peripheral surface of the large-diameter side flange. . In the hub unit bearing described in Japanese Patent Application Laid-Open No. 2005-3111, the axial length of the cylindrical surface portion for externally fitting the slinger is between the inner ring raceway and the rotary flange on the axially outer side in the axial direction. It becomes difficult to secure

SUMMARY OF THE INVENTION In view of the circumstances described above, the present invention provides a hub unit bearing that can ensure a sufficient fitting force of a slinger to a hub and can maintain good sealing performance by a sealing device for a long period of time. The purpose is to realize the structure.

A hub unit bearing according to one aspect of the present invention includes an outer ring, a hub, a plurality of rolling elements, and a sealing device.
The outer ring has a double-row outer ring raceway on its inner peripheral surface.
The hub includes a rotary flange provided at a portion located axially outside the outer ring and protruding radially outward, a double-row inner ring raceway provided on an outer peripheral surface, and the double-row and a cylindrical surface provided on the outer peripheral surface between the axially outer inner ring raceway and the rotating flange.
The plurality of rolling elements are rotatably arranged between the double-row outer ring raceway and the double-row inner ring raceway.
The seal device has a slinger and a seal ring, and closes the axially outer opening of the rolling element installation space existing between the inner peripheral surface of the outer ring and the outer peripheral surface of the hub.
The slinger includes a tubular portion that is externally fitted and fixed to the cylindrical surface portion, a side plate portion that is bent radially outward from an axially outer end of the tubular portion along the entire circumference, and the tubular portion. and a bent portion bent over the entire circumference from the axially inner end toward the radially inner side.
The seal ring has at least one seal lip whose tip portion is in sliding contact with or closely faces the axial inner surface of the side plate portion or the outer peripheral surface of the cylindrical portion.

The hub unit bearing according to one aspect of the present invention may further include a retaining ring engaged with the hub, and the retaining ring may hold down the axially inner end of the bent portion. .

In one aspect of the hub unit bearing of the present invention, the rolling elements may be tapered rollers.
In this case, the hub includes a large-diameter side flange provided in a portion of the double-row inner ring raceway axially outside the axially outer inner ring raceway, and an axially extending portion of the large-diameter side flange. It can have a roller sliding contact surface provided on the inner surface and inclined in a direction axially inward as it goes radially outward, and an inclined surface portion connecting the cylindrical surface portion and the roller sliding contact surface. . Further, the angle formed by the roller sliding contact surface and the inclined surface portion may be an obtuse angle, and the bent portion may be arranged radially outward of the inclined surface portion.

In the hub unit bearing according to one aspect of the present invention, the bent portion can be bent radially inward over the entire circumference from the axially inner end portion of the tubular portion, and can be further bent axially outwardly. .

According to the hub unit bearing of one aspect of the present invention, it is possible to ensure sufficient fitting force of the slinger to the hub, and to maintain good sealing performance of the sealing device for a long period of time.

FIG. 1 is a half sectional view showing a hub unit bearing of a first example of the embodiment. FIG. 2 is an enlarged view of part X in FIG. FIG. 3 is a diagram corresponding to FIG. 2, showing a modification of the first example of the embodiment. FIG. 4 is a diagram corresponding to FIG. 2, showing a second example of the embodiment. FIG. 5 is a diagram corresponding to FIG. 2 showing a modification of the second example of the embodiment. FIG. 6 is an enlarged cross-sectional view of a main part showing a third example of the embodiment. FIGS. 7A to 7D are enlarged cross-sectional views of essential parts showing four examples of modifications of the third example of the embodiment.

[First example]
1 and 2 show a first example of an embodiment of the invention. A hub unit bearing 1 of this example includes an outer ring 2, a hub 3, a plurality of rolling elements 4a and 4b, and a pair of sealing devices 5a and 5b. The hub unit bearing 1 of this example has a structure for drive wheels and uses tapered rollers as the rolling elements 4a and 4b.

The outer ring 2 is made of hard metal such as medium carbon steel. The outer ring 2 has double-row outer ring raceways 6a and 6b on its inner peripheral surface, and a stationary flange 7 protruding radially outward at its axial intermediate portion. Each of the outer ring raceways 6a and 6b is formed of a truncated cone surface inclined in a direction in which the inner diameter increases toward the direction away from each other in the axial direction. The stationary flange 7 has support holes 8 extending axially through it at a plurality of locations in the circumferential direction of the radially intermediate portion.

In this example, the support hole 8 is configured by a screw hole. The outer ring 2 is supported and fixed to the suspension system by screwing support bolts inserted through holes provided in the knuckle of the suspension system into the support holes 8 of the stationary flange 7 from the inside in the axial direction, thereby rotating the wheel. It doesn't rotate when you do it.

The hub 3 is arranged coaxially with the outer ring 2 radially inside the outer ring 2 . The hub 3 includes double-row inner ring raceways 9a and 9b, a pair of large-diameter side flanges 10a and 10b, and a rotary flange 11. As shown in FIG.

In this example, the hub 3 is formed by combining an inner ring 21 and a hub ring 22 .

The inner ring 21 is made of hard metal such as bearing steel. The inner ring 21 includes an axially inner inner ring raceway 9b and an axially inner large diameter side collar portion 10b.

The hub wheel 22 is made of hard metal such as medium carbon steel. The hub wheel 22 includes an axially outer inner ring raceway 9 a , an axially outer large diameter side collar portion 10 a , a rotary flange 11 , and a pilot portion 17 .

The hub wheel 22 has a small-diameter stepped portion 23, which has a smaller outer diameter than the portion adjacent to the axially outer side and is positioned axially inward of the axially outer inner ring raceway 9a, to which the inner ring 21 is fitted. have The hub 3 of this example is constructed by fitting the inner ring 21 to the small-diameter step portion 23 of the hub ring 22 with an interference fit so that the inner ring 21 and the hub ring 22 are coupled and fixed.

The respective inner ring raceways 9a and 9b are provided at portions of the outer peripheral surface of the hub 3 that face the double-row outer ring raceways 6a and 6b, and the outer diameters of the inner ring raceways 9a and 9b increase as they move away from each other in the axial direction. It is composed of a truncated conical surface inclined to

Of the pair of large-diameter side flanges 10a and 10b, the axially outer large-diameter side flange 10a is provided at a portion adjacent to the axially outer side of the axially outer inner ring raceway 9a. The axially outer large-diameter side collar portion 10a has a roller sliding contact surface 12a on its axially inner surface, an inclined surface portion 13 on its axially inner portion of its outer peripheral surface, and an axially outer portion of its outer peripheral surface. has a cylindrical surface portion 14a.

The roller sliding contact surface 12a is formed of a truncated cone surface that is inclined in the direction axially inward as it extends radially outward. The large-diameter side end surfaces of the rolling elements 4a in the axially outer row are brought into sliding contact with the roller sliding contact surfaces 12a in use.

The inclined surface portion 13 is cracked due to local overheating of the connecting portion between the roller sliding contact surface 12a of the large diameter side collar portion 10a and the cylindrical surface portion 14a during high-frequency heat treatment of the large diameter side collar portion 10a. In order to prevent defects such as damage and crystal coarsening, the truncated cone surface is inclined in the axially outward direction toward the radially outward side. The axially inner end of the inclined surface portion 13 is connected to the radially outer end of the roller sliding contact surface 12a. That is, the inclined surface portion 13 is bent axially outward and radially outward from the radially outer end portion of the roller sliding contact surface 12a. In this example, the angle θ1 formed between the roller sliding contact surface 12a and the inclined surface portion 13 is an obtuse angle or _a right angle. That is, the angle θ1 is set to ₉₀ degrees or more. Specifically, for example, the angle θ ₁ can be 90 degrees or more and 120 degrees or less, preferably more than 100 degrees and 110 degrees or less. In the illustrated example, the angle θ1 is _{approximately} 90 degrees. As a result, when the hub ring 22 constituting the hub 3 is subjected to heat treatment, local overheating of the connecting portion between the roller sliding contact surface 12a and the inclined surface portion 13 is prevented, thereby preventing damage such as cracking. ing. Incidentally, the inclined surface portion 13 may be composed of a compound surface composed of an inclined surface having the angle θ1 and _a chamfered portion having an arcuate cross-section connecting the inclined surface and the sliding contact surface 12a.

The axially inner end of the cylindrical surface portion 14 a is connected to the axially outer end of the inclined surface portion 13 . _The angle θ2 formed between the inclined surface portion 13 and the cylindrical surface portion 14a is an obtuse angle. That is, the angle θ2 is made larger _than 90 degrees. Specifically, for example, the angle θ2 can be set to be greater _than 90 degrees and 160 degrees or less, preferably greater than 140 degrees and 150 degrees or less. _In the illustrated example, the angle θ2 is approximately 150 degrees.

Of the pair of large-diameter side flange portions 10a and 10b, the axially inner large-diameter side flange portion 10b is provided at a portion adjacent to the axially inner side of the axially inner inner ring raceway 9b. The axially inner large-diameter flange portion 10b has a roller sliding contact surface 12b on its axially outer surface, and a cylindrical surface portion 14b on its axially inner portion of its outer peripheral surface.

The roller sliding contact surface 12b is formed of a truncated cone surface that is inclined in the axially outward direction toward the radially outward direction. The large-diameter side end surfaces of the rolling elements 4b in the axially inner row are in sliding contact with the roller sliding contact surfaces 12b in the state of use.

The rotary flange 11 is provided in a portion of the hub 3 located axially outside the axially outer end of the outer ring 2 so as to protrude radially outward. The rotating flange 11 has mounting holes 15 that penetrate in the axial direction at a plurality of locations in the circumferential direction of the radially intermediate portion. Studs 16 are press-fitted (serration-fitted) into each of the mounting holes 15 for connecting and fixing a rotating body for braking such as a disk or a drum and a wheel constituting a wheel to the rotating flange 11 . That is, in this example, the attachment hole 15 is configured by a press-fit hole.

A pilot portion 17 provided at the axially outer end of the hub 3 is inserted through a center hole provided at the center of each of the braking rotors and the wheel, and a circle at a radially intermediate portion of each is inserted. A hub nut is screwed onto the tip of the stud 16 while the stud 16 is inserted through through holes provided at a plurality of locations in the circumferential direction, whereby the stud 16 is coupled and fixed to the rotary flange 11 .

It should be noted that the mounting holes of the rotating flange can also be configured by screw holes. In this case, a hub bolt inserted through a through hole provided in the braking rotator and a through hole provided in the wheel is screwed into the mounting hole, thereby attaching the braking rotator and the wheel to the rotary flange. Bond and fix.

Further, the hub 3 has a flat surface portion 18 orthogonal to the central axis O of the hub 3 on the radially inner portion of the axially inner surface of the rotary flange 11, and has an axially outer portion on the outer peripheral surface of the axially intermediate portion. The cylindrical surface portion 14a (provided on the outer peripheral surface of the large-diameter side collar portion 10a on the axially outer side) and the flat surface portion 18 are connected to each other.

Since the hub unit bearing 1 of this example is a hub unit bearing for a drive wheel, the hub 3 has a spline hole 20 that penetrates in the axial direction at its center. The spline hole 20 is spline-engaged with the tip of a drive shaft that is rotationally driven by an engine or an electric motor as a drive source. When the vehicle is running, the hub 3 is rotated by the drive shaft, thereby rotating the wheels and the braking rotors coupled and fixed to the rotating flange 11 of the hub 3 .

However, the hub unit bearing of the present invention can also be applied to hub unit bearings for driven wheels. In this case, the spline holes can be omitted and the hub can be constructed solid.

A plurality of each of the rolling elements 4a, 4b are arranged between the double-row outer ring raceways 6a, 6b and the double-row inner ring raceways 9a, 9b while being held by a retainer 24 so as to be free to roll. It is Thereby, the hub 3 is rotatably supported radially inwardly of the outer ring 2 .

A pair of sealing devices 5 a and 5 b closes the openings on both sides in the axial direction of the rolling element installation space 25 existing between the inner peripheral surface of the outer ring 2 and the outer peripheral surface of the hub 3 . This prevents foreign matter such as muddy water from entering the rolling element installation space 25 from the external space, and prevents grease sealed in the rolling element installation space 25 from leaking to the external space.

Of the pair of seal devices 5 a and 5 b , the seal device 5 a that closes the axial outer opening of the rolling element installation space 25 includes a slinger 26 and a seal ring 27 .

The slinger 26 is formed into an annular shape as a whole by bending a rustproof metal plate such as a stainless steel plate into a substantially L-shaped cross section. The slinger 26 includes a tubular portion 28 , a side plate portion 29 and a bent portion 30 .

The tubular portion 28 has a cylindrical shape and is fitted and fixed to the axially outer cylindrical surface portion 14a of the hub 3 by an interference fit.

The side plate portion 29 is bent radially outward over the entire circumference from the axially outer end of the cylindrical portion 28 . The side plate portion 29 has a hollow circular plate-shaped flat portion 31 arranged radially outward, and a curved portion 32 arranged radially inward and having an arcuate cross section.

The flat plate portion 31 has its axial outer side surface in contact with the flat surface portion 18 of the rotary flange 11 without a gap.

The curved portion 32 connects the axially outer end of the tubular portion 28 and the radially inner end of the flat plate portion 31 . That is, the curved portion 32 connects the axially inner and radially inner end to the axially outer end of the cylindrical portion 28 and connects the axially outer and radially outer end to the flat plate portion. It is connected to the radially inner end of 31 .

The bent portion 30 is bent substantially at a right angle from the axially inner end of the cylindrical portion 28 toward the radially inner side over the entire circumference. That is, the bent portion 30 is formed in the shape of an inward flange. The bent portion 30 is arranged radially outward of the axially outer inclined surface portion 13 in a state where the cylindrical portion 28 is fitted and fixed to the cylindrical surface portion 14a. The distal end portion (the radially inner end portion) of the bent portion 30 faces the inclined surface portion 13 in close proximity, or the axially inner end portion of the cylindrical portion 28 is not deformed radially outwardly. is in light contact with

The seal ring 27 has a plurality (three in the illustrated example) of seal lips each of which has its tip portion in sliding contact with or closely faces the outer peripheral surface of the tubular portion 28 of the slinger 26 or the axial inner surface of the side plate portion 29 . 33a, 33b, 33c. In this example, the seal ring 27 has a metal core 34 internally fitted and fixed to the axially outer end of the outer ring 2 , and a plurality of seal lips 33 a , 33 b , 33 c , and is coupled to the metal core 34 . and a fixed seal body 35 .

The core metal 34 is formed into an annular shape as a whole by bending a metal plate such as a mild steel plate. The cored bar 34 includes a fitting tubular portion 36 , an outward flange portion 37 , and a bent plate portion 38 .

The fitting cylinder portion 36 is configured in a cylindrical shape, and the outer peripheral surface thereof is internally fitted and fixed to the inner peripheral surface of the axially outer end portion of the outer ring 2 by press fitting.

The outward flange portion 37 is bent at a right angle from the axially outer end portion of the fitting cylinder portion 36 toward the radially outer side, and has an axially inner surface that extends through a part of the base portion 39 of the seal body 35 described later. and abut against the axially outer end surface of the outer ring 2 .

The bent plate portion 38 is bent radially inward and axially outward from the axially inner end portion of the fitting cylinder portion 36 in a substantially V shape, and the tip portion is bent radially inwardly. .

The seal main body 35 is made of an elastic material such as an elastomer such as rubber, and is fixed (bonded) to the core metal 34 by vulcanization molding. The seal body 35 includes a base portion 39 , a plurality of seal lips 33 a , 33 b , 33 c , a weir portion 40 and a labyrinth lip 41 .

The base portion 39 includes, of the core metal 34, the radially outer end portion of the axial inner surface of the outward flange portion 37, the outer peripheral surface and the axial outer surface, the inner peripheral surface of the fitting cylinder portion 36, and the bent plate portion. It is coupled and fixed to the core metal 34 so as to cover the axially outer surface, the inner peripheral surface, and the radially inner end of the axially inner surface of 38 .

Each of the seal lips 33 a , 33 b , 33 c extends from the base portion 39 toward the outer peripheral surface of the tubular portion 28 of the slinger 26 or the axial inner surface of the side plate portion 29 , and has a distal end portion extending from the tubular portion 28 . It is slidably contacted or closely opposed to the outer peripheral surface or the axial inner surface of the side plate portion 29 over the entire circumference. In this example, the radially outermost seal lip 33a has its distal end in sliding contact with the axial inner surface of the flat plate portion 31 of the side plate portion 29 over the entire circumference, and the remaining two seal lips 33b and 33c. is brought into sliding contact with the outer peripheral surface of the cylindrical portion 28 over the entire circumference.

The weir portion 40 protrudes radially outward from a portion of the base portion 39 that covers the outer peripheral surface of the outward flange portion 37 . The weir portion 40 has a radially outer end projecting radially outward from the axially outer end surface of the outer ring 2 . As a result, the lubricant adheres to the outer peripheral surface of the outer ring 2 and travels along the outer peripheral surface of the outer ring 2 to enter the rolling element installation space 25 from between the axially outer end surface of the outer ring 2 and the axial inner surface of the rotary flange 11 . It can dam water that tries to invade.

The labyrinth lip 41 extends axially outward and radially outward from a portion of the base portion 39 that covers the outer peripheral surface of the outward flange portion 37 in a conical tubular shape. The labyrinth lip 41 has a tip end surface (an axially outer end surface) facing closely to a radially intermediate portion of the axially inner surface of the rotary flange 11 , and an axially outer portion of the inner peripheral surface that faces the side plate of the slinger 26 . It is closely opposed to the radially outer end surface of the portion 29 . Thus, a labyrinth seal 42 is formed between the labyrinth lip 41 and the hub 3 and slinger 26 .

Of the pair of seal devices 5a and 5b, the seal device 5b that closes the axially inner opening of the rolling element installation space 25 is composed of, for example, a combined seal ring. Specifically, the axially inner sealing device 5b has a substantially L-shaped cross-sectional shape, and is a slinger externally fitted and fixed to the axially inner end portion (axially inner cylindrical surface portion 14b) of the hub 3. and a seal ring having at least one seal lip whose tip portion is in sliding contact with or closely opposed to the surface of the slinger over the entire circumference, and which is internally fitted and fixed to the axially inner end portion of the outer ring 2 . can.

In the case of a hub unit bearing for a driven wheel, instead of or in addition to the combined seal ring, a hub unit bearing fixed to the axially inner end of the outer ring is used as the axially inner seal device. A bottomed cylindrical cover can also be used.

According to the hub unit bearing 1 of this embodiment, the fitting force of the slinger 26 constituting the axially outer seal device 5a to the hub 3 can be sufficiently ensured, and the sealing performance of the seal device 5a can be maintained for a long period of time. can be maintained well.

That is, in the hub unit bearing 1 of this example, the tubular portion 28 of the slinger 26 is formed with a slit opening at the inner end portion in the axial direction, like the conventional structure described in Japanese Patent Application Laid-Open No. 2017-207124. do not have. Therefore, in this example, the tip portions of the seal lips 33b and 33c can be brought into sliding contact with the outer peripheral surface of the tubular portion 28. As shown in FIG. Therefore, the sealing performance of the axially outer sealing device 5a can be maintained satisfactorily for a long period of time. In addition, it is possible to prevent deterioration of the rigidity of the cylindrical portion 28 in the circumferential direction, and to secure the fitting force of the slinger 26 to the cylindrical surface portion 14a of the hub 3 .

Further, in this example, the slinger 26 has a bent portion 30 that is bent substantially at a right angle from the axially inner end portion of the cylindrical portion 28 toward the radially inner side over the entire circumference. Therefore, the rigidity of the tubular portion 28 in the circumferential direction can be improved, and the fitting force of the slinger 26 to the cylindrical surface portion 14a of the hub 3 can be improved.

In particular, the hub unit bearing 1 of this example is designed to prevent local overheating of the connecting portion between the axial inner surface (roller sliding contact surface 12a) and the outer peripheral surface of the axially outer large diameter side collar portion 10a. The inclined surface portion 13 is formed on the axially outer portion of the outer peripheral surface of the radial side collar portion 10a, and has a structure in which it is difficult to secure the length of the cylindrical surface portion 14a for externally fitting and fixing the tubular portion 28 of the slinger 26. Therefore, according to the hub unit bearing 1 of the present embodiment, it is possible to significantly obtain the effect that the fitting force of the slinger 26 to the hub 3 can be sufficiently secured.

In the above-described conventional structure, the cylindrical portion of the slinger is formed with a slit opening at the axially inner end portion. Therefore, in the conventional structure, when the axially inner end portion of the tubular portion is pressed by a jig when the slinger is press-fitted into the hub, the slits of the tubular portion adjacent in the circumferential direction are not aligned. Buckling deformation of the intermediate portion may occur. Therefore, in the conventional structure, when the slinger is press-fitted into the hub, the side plate portion (annular portion) that is bent radially outward from the axially outer end portion of the tubular portion is axially inward. It is necessary to press the side surface with a jig. When the axial inner surface of the side plate portion is pressed by a jig, the side plate portion may be deformed so as to fall down, thereby deteriorating workability.

On the other hand, in this example, the tubular portion 28 of the slinger 26 is not formed with a slit that opens to the axially inner end, and the axially inner end of the tubular portion 28 is fully extended from the axially inner end. A bending portion 30 that is bent substantially at a right angle toward the inner side in the radial direction is formed over the circumference, and the rigidity in the axial direction of the cylindrical portion 28 is sufficiently high. Therefore, by pressing the axially inner end portion of the cylindrical portion 28 and the axially inner side surface of the bent portion 30 with a jig, the slinger 26 can be press-fitted into the axially outer cylindrical surface portion 14a. It is possible to prevent deterioration of the properties.

In addition, in the conventional structure, when the slinger is attached to the hub, the claw portion formed at the axially inner end portion of the cylindrical portion is elastically deformed radially outward, and the cylindrical portion is attached to the hub. must be pressed into. Then, in a state in which the axial positions of the recess formed in the outer peripheral surface of the hub and the pawl are aligned, the pawl is elastically restored, and the pawl and the recess are engaged with each other.

On the other hand, in this example, the bent portion 30 of the slinger 26 is arranged radially outward of the axially outer inclined surface portion 13 while the cylindrical portion 28 is fitted and fixed to the cylindrical surface portion 14a. That is, when the slinger 26 is attached to the hub 3, the bent portion 30 does not interfere with the outer peripheral surface of the hub 3, and the bent portion 30 is directed radially outward like the claw portion of the conventional structure. No need for elastic deformation. From this aspect as well, it is possible to prevent deterioration of the workability of attaching the slinger 26 to the hub 3 .

In the hub unit bearing 1 of this example, tapered rollers are used as the rolling elements 4, but balls may be used instead of the tapered rollers. It can also be applied to an equal-diameter PCD type hub unit bearing in which the pitch diameter of the rolling elements in the axially inner row and the pitch diameter of the rolling elements in the axially outer row are equal, or the axially inner row can be applied. It can also be applied to hub unit bearings of the different diameter PCD type in which the pitch diameter of the rolling elements in the outer row is larger or smaller than the pitch diameter of the rolling elements in the axially outer row.

Further, the hub unit bearing of the present invention is not limited to the hub unit bearing 1 for driving wheels having the spline hole 20 axially penetrating through the hub 3 in the center as in this example. It can also be applied to a hub unit bearing for a driven wheel, which is an entity.

[Modification of the first example]
FIG. 3 shows a modification of the first embodiment of the invention. In this modification, the slinger 26a has a bent portion 30a that is bent radially inward along the entire circumference from the axially inner end portion of the cylindrical portion 28 and further bent axially outwardly. That is, the bent portion 30a is formed by a bent portion that is bent radially inward and axially outward from the axially inner end portion of the cylindrical portion 28 so as to have a substantially U-shaped cross section. The bent portion 30a is arranged radially outward of the axially outer inclined surface portion 13 in a state where the cylindrical portion 28 is fitted and fixed to the cylindrical surface portion 14a.

[Second example]
FIG. 4 shows a second example of an embodiment of the invention. In this example, a retaining ring 43 having a circular cross-sectional shape is engaged with the axially intermediate portion of the inclined surface portion 13 on the axially outer side of the hub 3 , and the retaining ring 43 supports the bent portion 30 of the slinger 26 . The inner end of the direction is pressed. Specifically, the axially outer end of the retaining ring 43 abuts against the axially inner surface of the inward flange-shaped bent portion 30 .

In addition, in this example, the outer diameter of the retaining ring 43 is made smaller than the outer diameter of the tubular portion 28 . As a result, when the hub unit bearing is assembled, the tubular portion 28 of the slinger 26 is externally fitted and fixed to the cylindrical surface portion 14a of the hub 3, and after the retaining ring 43 is engaged, the outer end portion in the axial direction is sealed. This prevents the seal lips 33b and 33c of the seal ring 27 from being caught by the retaining ring 43 when the hub 3 is inserted from the axial outside into the outer ring 2 in which the ring 27 is fitted and fixed.

According to the hub unit bearing of this example, it is possible to more reliably prevent the axially inward relative movement of the slinger 26 with respect to the hub 3 . Other configurations and effects are the same as those of the first embodiment.

[Modification of Second Example]
FIG. 5 shows a modification of the second embodiment of the invention. In this modification, a retaining ring 43a having a rectangular cross-sectional shape is engaged with the axially intermediate portion of the inclined surface portion 13 on the axially outer side of the hub 3, and the retaining ring 43a allows the bending portion 30a of the slinger 26a to move. The inner end in the axial direction is held down. Specifically, the axially outer surface of the retaining ring 43a abuts against the axially inner end of the bent portion 30a having a substantially U-shaped cross section.

The retaining ring 43 a has an outer diameter smaller than that of the tubular portion 28 . This prevents the seal lips 33b and 33c of the seal ring 27 from being caught by the snap ring 43a during assembly of the hub unit bearing.

According to the hub unit bearing of this modified example, as in the second example of the embodiment, it is possible to more reliably prevent the relative movement of the slinger 26a relative to the hub 3 in the axial direction.

It is also possible to combine the snap ring 43a having a rectangular cross-sectional shape as in this modified example and the slinger 26 having the inward flange-shaped bent portion 30 as in the second example of the embodiment.

Moreover, it is also possible to combine the retaining ring 43 having a circular cross-sectional shape as in the second embodiment and the slinger 26a having a bent portion 30a having a substantially U-shaped cross section as in this modified example. However, in this case, the outer diameter of the retaining ring 43 is made smaller than the outer diameter of the tubular portion 28, and the center axis of the slinger 26a is the center and passes through the turning point (apex) of the bent portion 30a. It should be at least the diameter of a circle. If the outer diameter of the retaining ring 43 is smaller than the diameter, the retaining ring 43 exerts a radially outward force on the bent portion 30a of the slinger 26a, which may reduce the fitting force of the slinger 26a to the hub 3. This is because of the nature of

[Third example]
FIG. 6 shows a third example of an embodiment of the invention. This example is an example in which the present invention is applied to a hub unit bearing using balls as rolling elements. For this reason, the hub 3a has a double-row inner ring raceway 9c having an arcuate cross-sectional shape (generatrix shape) on its outer peripheral surface, and a shoulder portion 44 at a portion axially adjacent to the inner ring raceway 9c. . In FIG. 6, only the axially outer inner ring raceway 9c and the shoulder portion 44 provided at a portion adjacent to one axial side of the axially outer inner ring raceway 9c are illustrated.

The axially outer shoulder portion 44 has a cylindrical surface portion 14c on the axially outer portion of the outer peripheral surface, and a stepped portion 45 having an outer diameter smaller than that of the cylindrical surface portion 14c on the axially inner portion of the outer peripheral surface.

In this example, the bent portion 30 is positioned radially outward of the stepped portion 45 while the cylindrical portion 28 of the slinger 26 is externally fitted and fixed to the cylindrical surface portion 14a by interference fit. That is, the tip portion of the bent portion 30 is closely opposed to the stepped portion 45, or the axially inner end portion of the cylindrical portion 28 is in light contact with the stepped portion 28 to such an extent that it is not deformed radially outward.

As with the hub unit bearing 1 of the first example of the embodiment, the hub unit bearing of this example can also ensure a sufficient fitting force of the slinger 26 with respect to the hub 3, and the sealing performance of the sealing device 5a can be improved. It can be maintained well for a long period of time. Other configurations and effects are the same as those of the first embodiment.

[Modification of the third example]
FIGS. 7A to 7D show first to fourth examples of modifications of the third example of the embodiment.

In a first modified example shown in FIG. 7A, the cylindrical portion 28 of the slinger 26a is fitted onto the cylindrical surface portion 14c of the hub 3a by interference fit, and the bent portion 30a having a substantially U-shaped cross section is formed into a stepped portion. It is located radially outside the portion 45 .

In a second modified example shown in FIG. 7B, a snap ring 43a having a rectangular cross-sectional shape is engaged with the axially intermediate portion of the stepped portion 45, and the snap ring 43a constitutes the slinger 26. The axially inner end of the bent portion 30 is held down. Specifically, the axially outer surface of the retaining ring 43a abuts against the axially inner surface of the inward flange-shaped bent portion 30 . This more reliably prevents the axially inward relative movement of the slinger 26a with respect to the hub 3a.

In a third modified example shown in FIG. 7C, a snap ring 43 having a circular cross-sectional shape is engaged with the axially intermediate portion of the stepped portion 45, and the snap ring 43 constitutes the slinger 26. The axially inner end of the bent portion 30 is held down. Specifically, the axially outer end of the retaining ring 43 abuts against the axially inner surface of the inward flange-shaped bent portion 30 . This more reliably prevents the axially inward relative movement of the slinger 26 with respect to the hub 3a.

In addition, in the second example and the third example of the modification, the outer diameter of the retaining rings 43a, 43 is made smaller than the outer diameter of the tubular portion 28, as in the second example of the embodiment. This prevents the seal lips 33b, 33c of the seal ring 27 from being caught by the retaining rings 43a, 43 during assembly of the hub unit bearing.

In a fourth modified example shown in FIG. 7D, a retaining ring 43 having a circular cross-sectional shape is engaged with the axially intermediate portion of the stepped portion 45, and the retaining ring 43 constitutes the slinger 26. It holds down the axial inner end of the bent portion 30a. Specifically, the axially outer end of the retaining ring 43 abuts against the axially inner end of the bent portion 30a having a U-shaped cross section. This more reliably prevents the axially inward relative movement of the slinger 26a with respect to the hub 3a.

In addition, in the fourth example of the modified example, the outer diameter of the retaining ring 43 is made smaller than the outer diameter of the tubular portion 28, and is centered on the central axis of the slinger 26a, ) is greater than or equal to the diameter of the circle passing through

The first to third examples of the embodiment described above and their modifications can be combined as appropriate and carried out as long as there is no contradiction.

Reference Signs List 1 hub unit bearing 2 outer ring 3 hub 4a, 4b rolling elements 5a, 5b sealing device 6a, 6b outer ring raceway 7 stationary flange 8 support hole 9a, 9b, 9c inner ring raceway 10a, 10b large diameter side flange 11 rotating flange 12a, 12b Roller sliding contact surface 13 Inclined surface portion 14a, 14b Cylindrical surface portion 15 Mounting hole 16 Stud 17 Pilot portion 18 Flat surface portion 19 Corner R portion 20 Spline hole 21 Inner ring 22 Hub ring 23 Small diameter stepped portion 24 Cage 25 Rolling element installation space 26, 26a Slinger 27 Seal ring 28 Cylindrical part 29 Side plate part 30, 30a Bending part 31 Flat plate part 32 Bending part 33a, 33b, 33c Seal lip 34 Core metal 35 Seal main body 36 Fitting cylinder part 37 Outward brim part 38 Bending plate part 39 Base part 40 weir portion 41 labyrinth lip 42 labyrinth seal 43, 43a retaining ring 44 shoulder portion 45 stepped portion

Claims (4)

an outer ring having a double-row outer ring raceway on its inner peripheral surface;
A rotating flange provided at a portion located axially outside the outer ring and protruding radially outward, a double-row inner ring raceway provided on the outer peripheral surface, and the double-row inner ring raceway in the axial direction. a hub having a cylindrical surface provided on an outer peripheral surface between the axially outer inner ring raceway and the rotary flange;
a plurality of rolling elements rollably arranged between the double-row outer ring raceway and the double-row inner ring raceway;
a seal device having a slinger and a seal ring, and closing an axially outer opening of the rolling element installation space existing between the inner peripheral surface of the outer ring and the outer peripheral surface of the hub;
The slinger includes a tubular portion that is externally fitted and fixed to the cylindrical surface portion, a side plate portion that is bent radially outward from an axially outer end of the tubular portion along the entire circumference, and the tubular portion. and a bent portion bent over the entire circumference from the axially inner end toward the radially inner side,
The seal ring has at least one seal lip whose tip portion is in sliding contact with or closely faces the axial inner surface of the side plate portion or the outer peripheral surface of the cylindrical portion,
hub unit bearings. further comprising a retaining ring engaged with the hub;
The snap ring holds down an axially inner end of the bent portion,
A hub unit bearing according to claim 1. The rolling elements are composed of tapered rollers,
The hub includes a large-diameter side flange provided at a portion of the double-row inner ring raceway located axially outside of the axially outer inner ring raceway, and an axially inner surface of the large-diameter side flange. a roller sliding contact surface that is provided and inclined in a direction axially inward toward the radially outer side; and an inclined surface portion that connects the cylindrical surface portion and the roller sliding contact surface,
an angle formed by the roller sliding contact surface and the inclined surface portion is an obtuse angle,
The bent portion is arranged radially outward of the inclined surface portion,
A hub unit bearing according to claim 1 or 2. The bent portion is bent radially inward from the axially inner end of the cylindrical portion along the entire circumference, and is further bent axially outward.
A hub unit bearing according to any one of claims 1 to 3.

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