JP2022126993A - hub unit bearing - Google Patents

Abstract

To actualize structure enabling suppression of the axial displacement of a slide contact ring with respect to a hub.SOLUTION: A sealing device 6 blocking an opening on the axial outside of an internal space 32 existing between the inner periphery of an outer ring 2 and the outer periphery of a hub 3 comprises a sliding contact ring 33 supported by the hub 3, and a sliding ring 34 supported by the outer ring 2. The sliding contact ring 33 has, in the radial outside portion thereof, a through-hole 41 through which a shaft portion 15 of a hub bolt 5 is inserted. A circumference of the through-hole 41 is axially held between the axial inside face of a rotary flange 12 and the axial outside face of a head 16 of the hub bolt 5, so that the sliding contact ring is supported by the hub 3. The sliding ring 34 has seal lips 49b, 49c coming in slide-contact with the axial inside face of a radial inside portion of the sliding contact ring 33.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.

Regarding the hub unit bearing, the axially outer side is the widthwise outer side of the vehicle when assembled to the vehicle, and the axially inner side is the widthwise central side of the vehicle when the hub unit bearing is assembled to the vehicle.

The hub unit bearing further includes a sealing device that closes the axially outer opening of the internal space that exists between the inner peripheral surface of the outer ring and the outer peripheral surface of the hub. Conventionally, such a seal device is supported and fixed to the axially outer end of the outer ring, and the respective tip portions are brought into sliding contact with the axially intermediate outer peripheral surface of the hub or the axially inner surface of the rotary flange. A seal ring having a plurality of seal lips is widely known.

Here, as described in Japanese Unexamined Patent Application Publication No. 2017-180599 (Patent Document 1), the part of the outer peripheral surface of the hub with which the tip of the seal lip slides is provided with a formed grinding wheel (rotary wheel wheel). ) is used for finishing. When finishing the outer peripheral surface of the hub using a formed grinding wheel, in order to generate a force that presses the outer peripheral surface of the hub against the shoe, the central axis of the hub is eccentric with respect to the magnetic chuck. support in the state. Although the shoe is made of cemented carbide to prevent wear, wear of the shoe is unavoidable during mass production, so the center height of the hub and the center height of the grinding wheel tend to be inconsistent. 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.

In order to solve the problem caused by the grinding streaks, for example, Japanese Patent Application Laid-Open No. 2017-032008 (Patent Document 2) discloses a seal ring supported and fixed to the axially outer end of the outer ring, and an outer peripheral surface of the hub. A plurality of seals forming a seal ring, comprising a sliding contact ring made of a metal plate, which is fitted and fixed to the cylindrical surface portion positioned between the rotating flange and the inner ring raceway of the axially outer row in the axial direction. A sealing device is disclosed in which the tip of the lip is brought into sliding contact with the surface of the sliding ring.

JP 2017-180599 A Japanese Unexamined Patent Application Publication No. 2017-032008

By the way, a moment load based on road reaction force is applied to the hub unit bearing mainly when the automobile turns. Stress due to such a moment load tends to concentrate on the connecting portion between the axially inner surface of the rotating flange and the outer peripheral surface of the axially intermediate portion of the hub. For this reason, this connecting portion is usually configured by a concave surface portion (corner R portion) having a large radius of curvature.

In addition, hub unit bearings are required to have a large moment rigidity in order to keep the camber angle of the wheels constant and ensure the steering stability of the vehicle regardless of the moment load based on the reaction force of the road surface. For this reason, in the hub unit bearing, the rolling elements are provided with a back-to-back (DB) type contact angle. Furthermore, from the viewpoint of improving the moment rigidity, it is preferable to increase the row-to-row distance between the rolling elements arranged in double rows as much as possible.

As described above, if the connecting portion between the axially inner surface of the rotary flange and the outer peripheral surface of the axially intermediate portion of the hub is configured with a concave curved surface portion having a large radius of curvature, or if the row-to-row distance between the rolling elements is increased, In addition, it becomes difficult to ensure the axial dimension of the cylindrical surface portion of the outer peripheral surface of the hub located between the rotary flange and the inner ring raceway of the axially outer row in the axial direction. If the axial dimension of this cylindrical surface portion cannot be sufficiently secured, and the fitting length of the sliding contact ring to the hub cannot be secured sufficiently, the sliding contact ring rotates (creeps) with respect to the hub, or the axial direction becomes It becomes easier to displace.

When the sliding contact ring with respect to the hub is displaced in the axial direction, the axial interference of the seal lip against the surface of the sliding contact ring increases, resulting in an increase in the seal torque or the sealing against the surface of the sliding contact ring. There is a possibility that the axial interference of the lip will decrease and the sealing performance will deteriorate.

SUMMARY OF THE INVENTION An object of the present invention is to realize a structure capable of suppressing axial displacement of a sliding contact ring with respect to a hub.

A hub unit bearing of the present invention includes an outer ring, a hub, a plurality of rolling elements, a plurality of hub bolts, and a sealing device.
The outer ring has a double-row outer ring raceway on its inner peripheral surface.
The hub has a double-row inner ring raceway on its outer peripheral surface, and a rotary flange protruding radially outward at a portion located axially outside the outer ring.
The rotating flange has a thick portion provided radially inward and a mounting portion provided radially outward, which is smaller in axial dimension than the thick portion and penetrates in the axial direction at a plurality of locations in the circumferential direction. a thin-walled portion having a hole; and a radially-outwardly-facing edge connecting the radially outer end of the axially inner surface of the thicker portion and the radially inner end of the axially inner surface of the thinned portion. stepped portion.
A plurality of the rolling elements are arranged for each row between the double-row outer ring raceway and the double-row inner ring raceway.
Each of the hub bolts has a shaft portion press-fitted into the mounting hole from the inside in the axial direction, and a head portion adjacent to the inside in the axial direction of the shaft portion and having a larger outer diameter than the shaft portion.
The seal device has a sliding contact ring supported by the hub and a seal ring supported by the outer ring, and has an internal space existing between an inner peripheral surface of the outer ring and an outer peripheral surface of the hub. It closes the opening on the outside in the axial direction.
The sliding contact ring has a radial position regulating portion that is fitted onto the outer peripheral surface of the hub without rattling in the radial direction, and a through hole that is provided on the radially outer portion and through which the shaft portion is inserted. The peripheral portion of the through hole is axially sandwiched between the axially inner side surface of the rotary flange and the axially outer side surface of the head, thereby being supported by the hub and radially An inner portion is spaced axially inward from the axially inner surface of the thickened portion.
The seal ring has a seal lip in sliding contact with the axial inner surface of the sliding ring.

In one aspect of the present invention, the rotating flange has a small-diameter portion on the outer peripheral surface of the axially inner portion, the outer diameter of which is smaller than that of the portion adjacent to the axially outer side, and the radial position restricting portion includes the small-diameter portion. It is fitted on the outside of the part.

In one aspect of the present invention, the radial position restricting portion is fitted onto the stepped portion.

In one aspect of the present invention, the radial position regulating portion is located on the outer peripheral surface of the hub between the rotary flange and the inner ring raceway in the axially outer row among the double-row inner ring raceways in the axial direction. It is fitted on the part where it is located.

According to the present invention, axial displacement of the sliding contact ring with respect to the hub can be suppressed.

FIG. 1 is a half sectional view of a hub unit bearing of a first example of the embodiment. FIG. 2 is an enlarged view of a part of FIG. FIG. 3 is a diagram corresponding to FIG. 2 regarding the second example of the embodiment. FIG. 4 is a diagram corresponding to FIG. 2 regarding the third example of the embodiment. FIG. 5 is a diagram corresponding to FIG. 2 regarding a fourth example of the embodiment. FIG. 6 is a diagram corresponding to FIG. 2 regarding the fifth example of the embodiment. FIG. 7 is a diagram corresponding to FIG. 2 regarding the sixth example of the embodiment.

[First example of embodiment]
A first example of an embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG.

A hub unit bearing 1 of this example is for a driven wheel and includes an outer ring 2, a hub 3, a plurality of balls 4 each of which is a rolling element, a plurality of hub bolts 5, a seal device 6, a bearing a cap 7;

Regarding the hub unit bearing 1, the axially outer side is the left side in FIGS. It is the right side of FIG.1 and FIG.2 which becomes the width direction center side.

The outer ring 2 is made of hard metal such as medium carbon steel. The outer ring 2 has double-row outer ring raceways 8a and 8b on its inner peripheral surface, and a stationary flange 9 protruding radially outward at its axial intermediate portion. The stationary flange 9 has support holes 10 extending axially through it at a plurality of locations in the circumferential direction of the radially intermediate portion. The outer ring 2 is supported and fixed to the suspension system by means of support bolts screwed into support holes 10 of the stationary flange 9, so that it does not rotate even when the wheel rotates.

The hub 3 is arranged coaxially with the outer ring 2 radially inward of the outer ring 2, and has double-row inner ring raceways 11a and 11b facing the double-row outer ring raceways 8a and 8b on its outer peripheral surface. The hub 3 has a rotary flange 12 protruding radially outward at a portion located axially outside the outer ring 2 and has a cylindrical pilot portion 13 at the axially outer end. The rotating flange 12 has mounting holes 14 that penetrate in the axial direction at a plurality of locations in the circumferential direction of the radially outer portion.

A plurality of hub bolts 5 are used to connect a wheel constituting a wheel and a braking rotor such as a disc or drum to the rotary flange 12 . The hub bolts 5 are supported and fixed to the rotary flange 12 by press-fitting them into the mounting holes 14 one by one.

Specifically, each of the hub bolts 5 has a shaft portion 15 and a head portion 16 that is adjacent to the axially inner side of the shaft portion 15 and has a larger outer diameter than the shaft portion 15 . The shaft portion 15 has a male threaded portion 17 on the outer peripheral surface of the axially outer half portion, and has a serration portion 51 on the outer peripheral surface of the axially inner portion near the end portion. Each of the hub bolts 5 inserts the shaft portion 15 into the mounting hole 14 from the inside in the axial direction, and press-fits the serration portion 51 into the mounting hole 14 from the inside in the axial direction. portion is bitten into the inner peripheral surface of the mounting hole 14 , so that it is supported and fixed to the rotary flange 12 . In this state, the male threaded portion 17 protrudes axially outward from the axial outer surface of the rotary flange 12 . The axially outer surface of the head 16 abuts against the axially inner surface of the rotary flange 12 via a portion of the sliding contact ring 33 (the portion surrounding the through hole 41), which will be described later. This restricts the axial position of the hub bolt 5 with respect to the rotary flange 12 .

Braking rotating bodies such as discs and drums, and wheels that make up the wheels, have a central hole provided in the center, through which the pilot portion 13 is inserted, and are provided at a plurality of locations in the radial intermediate portion in the circumferential direction. A hub nut (not shown) is screwed onto the axially outer end of the male threaded portion 17 while the shaft portion 15 of the hub bolt 5 is inserted into the through hole, thereby coupling the rotary flange 12 with the shaft portion 15 .

In this example, the rotary flange 12 includes a thick portion 18 provided radially inward, a thin portion 19 provided radially outward and having a smaller axial dimension than the thick portion 18, and the thick portion 18. It has a radially outward facing step 20 connecting the radially outer end of the axially inner surface and the radially inner end of the axially inner surface of the thin portion 19 . In this example, the stepped portion 20 has a linear generatrix shape (cross-sectional shape) that is inclined radially outward as it goes axially outward. That is, the stepped portion 20 is configured by a conical surface. Each of the mounting holes 14 is provided at a plurality of locations that are equally spaced in the circumferential direction of the thin portion 19 .

The rotary flange 12 (thin-walled portion 19 ) has a small-diameter portion 21 on the outer peripheral surface of the axially inner portion, and has a smaller diameter than the small-diameter portion 21 on the outer peripheral surface of the axially intermediate portion adjacent to the axially outer side of the small-diameter portion 21 . It has a large diameter portion 22 with a large outer diameter. The rotating flange 12 has a locking groove 23 recessed axially inward along the entire periphery of the axially inner side surface of the thin portion 19 , which is located radially inwardly of the mounting hole 14 .

Further, the hub 3 has a cylindrical shoulder portion 24 at a portion of the outer peripheral surface adjacent to the axially outer side of the inner ring raceway 11a of the axially outer row. Further, the hub 3 has an arcuate cross-sectional shape that connects the radially inner end of the axially inner surface of the rotary flange 12 (thick portion 18) and the axially outer end of the shoulder portion 24. It has a corner R portion 25 which is a concave curved surface portion.

The hub 3 of this example is formed by combining an inner ring 26 and a hub ring 27 .

The inner ring 26 is made of hard metal such as bearing steel. The inner ring 26 has, on its outer peripheral surface, the inner ring raceway 11b in the axially inner row among the double-row inner ring raceways 11a and 11b.

The hub wheel 27 is made of hard metal such as medium carbon steel. The hub wheel 27 has the inner ring raceway 11a in the axially outer row among the double-row inner ring raceways 11a and 11b in the axially intermediate portion of the outer peripheral surface. The hub wheel 27 has a rotating flange 12 protruding radially outward at a portion located axially outside the inner ring raceway 11a of the axially outer row, and has a cylindrical shape at its axially outer end. It has a shaped pilot portion 13 .

The hub wheel 27 has an outer diameter dimension smaller than that of the portion adjacent to the axially outer side, and the inner ring 26 is fitted onto the portion of the outer peripheral surface located axially inward of the inner ring raceway 11a of the axially outer row. It has a small-diameter stepped portion 28 . The hub wheel 27 further has a crimped portion 29 that is bent radially outward from the axially inner end of the portion provided with the small diameter stepped portion 28 on the outer peripheral surface and presses the axially inner end face of the inner ring 26 . That is, the hub 3 of this example bends radially outward from the axially outer end portion of the small diameter stepped portion 28 in a state in which the inner ring 26 is fitted onto the small diameter stepped portion 28 of the hub wheel 27 with an interference fit. The inner ring 26 is sandwiched from both sides in the axial direction between the stepped surface 30 facing inward in the axial direction and the axial outer side surface of the crimped portion 29, and the inner ring 26 and the hub ring 27 are fixedly connected. there is

A plurality of balls 4 are arranged in each row between the double-row outer ring raceways 8a, 8b and the double-row inner ring raceways 11a, 11b, and are spaced apart in the circumferential direction. is rotatably held by a retainer 31 of . Thereby, the hub 3 is rotatably supported radially inwardly of the outer ring 2 . In this example, balls 4 are used as rolling elements, but tapered rollers can also be used as rolling elements. In this example, the pitch diameter of the balls 4 in the axially outer row is the same as the pitch diameter of the balls 4 in the axially inner row. It can also be applied to a different diameter PCD type hub unit bearing in which the pitch diameter and the pitch diameter of the rolling elements in the axially inner row are different from each other.

A substantially cylindrical internal space 32, which exists between the inner peripheral surface of the outer ring 2 and the outer peripheral surface of the hub 3 and in which the balls 4 are arranged, is filled with grease as a lubricant. The rolling contact portions between the surfaces (rolling surfaces) of the balls 4 and the outer ring raceways 8a and 8b and the inner ring raceways 11a and 11b, and the sliding contact portions between the surfaces of the balls 4 and the inner surfaces of the pockets of the retainer 31 form an internal space. It is lubricated by grease enclosed in 32.

The axially outer opening of the internal space 32 is closed by the sealing device 6 , and the axially inner opening of the outer ring 2 is closed by the bearing cap 7 . As a result, foreign matter such as muddy water enters the internal space 32 from the external space through the axially outer opening of the internal space 32 and the axially inner opening of the outer ring 2, and the grease sealed in the internal space 32 is released. It prevents leakage to the outside space.

The seal device 6 includes a sliding contact ring 33 supported by the hub 3 and a seal ring 34 supported by the outer ring 2 .

The sliding contact ring 33 is formed by pressing a corrosion-resistant metal plate, and has an annular shape as a whole. The sliding contact ring 33 includes a sliding contact cylindrical portion 35 , a sliding contact inclined plate portion 36 , a sliding contact side plate portion 37 , a step plate portion 38 , a mounting plate portion 39 , and a fitting cylindrical portion 40 .

The sliding cylindrical portion 35 constitutes a radially inner end portion of the sliding contact ring 33 . The slidable contact inclined plate portion 36 is bent radially outward from the axially outer end portion of the slidable contact cylindrical portion 35, and is formed in a conical cylindrical shape inclined radially outward toward the axially outer side. ing. The sliding contact side plate portion 37 is bent radially outward from the radially outer end portion of the sliding contact inclined plate portion 36 and is configured in a ring plate shape. The stepped plate portion 38 is formed in a conical cylindrical shape that is bent axially outward from the radially outer end portion of the sliding contact side plate portion 37 and inclined radially outwardly toward the axially outer side. . The mounting plate portion 39 is bent radially outward from the radially outer end portion of the stepped plate portion 38 and is configured in a ring plate shape. Further, the mounting plate portion 39 has through holes 41 at a plurality of locations aligned with the mounting holes 14 of the rotary flange 12 . The fitting tube portion 40 is bent axially outward from the radially outer end portion of the mounting plate portion 39 to have a cylindrical shape. It should be noted that the step plate portion 38 may be provided with a rib or the like for improving strength.

The sliding contact ring 33 is axially sandwiched between the axial inner surface of the rotary flange 12 and the axial outer surface of the head 16 of the hub bolt 5 at the portions surrounding the through holes 41 of the mounting plate portion 39 . is supported by the hub 3.

More specifically, in a state where the sliding contact ring 33 is attached to the hub 3, the fitting cylinder portion 40 is fitted to the small-diameter portion 21 of the outer peripheral surface of the rotary flange 12 with a clearance fit without radial play. is fitted. Thereby, the radial position of the sliding contact ring 33 with respect to the hub 3 is restricted. Further, in this state, the fitting cylinder portion 40 does not protrude radially outward beyond the large-diameter portion 22 adjacent to the small-diameter portion 21 on the outer peripheral surface of the rotary flange 12 . In addition, in this example, the fitting cylinder part 40 corresponds to a radial position control part.

Further, the axially outer side surface of the mounting plate portion 39 is in contact with the axially inner side surface of the thin portion 19 of the rotary flange 12 . Thereby, the axial position of the sliding contact ring 33 with respect to the hub 3 is regulated. Further, each of the through holes 41 is arranged at a position (radial position and circumferential position) aligned with the mounting hole 14 of the rotary flange 12 .

The step plate portion 38 is spaced radially outward (and axially inward) with respect to the step portion 20 of the rotary flange 12 . Further, the sliding contact side plate portion 37 is spaced axially inward from the axial inner surface of the thick portion 18 of the rotary flange 12 . The slidable contact inclined plate portion 36 is spaced radially outward (and axially inward) with respect to the corner R portion 25 of the hub 3 . Further, the sliding cylindrical portion 35 is spaced radially outward from the shoulder portion 24 of the hub 3 .

In this state, the shaft portion 15 of the hub bolt 5 is inserted from the inside in the axial direction into the through hole 41 and the mounting hole 14 that are aligned with each other. An axially inner end portion of the shaft portion 15 is inserted through 41 . Along with this, the portions surrounding the through holes 41 of the mounting plate portion 39 are axially spaced between the axially inner surface of the thin portion 19 of the rotary flange 12 and the axially outer surface of the head portion 16 of the hub bolt 5 . The sliding contact ring 33 is supported by the hub 3 by being sandwiched between the two.

Further, in the structure of this example, in a state where the sliding contact ring 33 is attached to the hub 3, the entire circumference of the portion between the hub 3 and the sliding contact ring 33 is sealed by an O-ring 42 as a sealing material. . Specifically, the O-ring 42 is engaged with the engagement groove 23 provided on the axially inner side surface of the thin portion 19 of the rotary flange 12, and is positioned on the bottom surface of the engagement groove 23 (inwardly in the axial direction). ) and the axial outer surface of the mounting plate portion 39 of the sliding contact ring 33 are elastically compressed. In this state, the O-ring 42 prevents foreign matter such as muddy water from entering the internal space 32 from the external space through the portion between the hub 3 and the sliding contact ring 33, and prevents the grease sealed in the internal space 32 from entering. Prevent leakage to the outside space.

The seal ring 34 includes a metal core 43 and a seal material 44 .

The cored bar 43 is formed by pressing a metal plate, and has an annular shape as a whole. The core metal 43 includes a cylindrical fitting tube portion 45, a circular plate-shaped standing plate portion 46 bent radially outward from an axially outer end portion of the fitting tube portion 45, and a fitting tube portion. A support plate portion 47 having a crank-shaped cross section bent radially inward and bent radially inward and axially outward in a U-shape from the axially inner end portion of the portion 45 . The core metal 43 is supported and fixed to the outer ring 2 by fitting the cylindrical fitting portion 45 to the inner peripheral surface of the axially outer end of the outer ring 2 by interference fit. Further, in this state, the axial inner surface of the upright plate portion 46 is attached to the axially outer end surface of the outer ring 2 and a portion of the seal material 44 (the diameter of the axial inner surface of the upright plate portion 46 in the seal base portion 48). The axial position of the cored bar 43 with respect to the outer ring 2 is regulated by abutting the cored bar 43 via the portion covering the end portion on the direction outer side.

The sealing member 44 is made of an elastic material such as elastomer such as rubber (for example, by vulcanization molding), and is coupled and fixed to the metal core 43 . The seal member 44 includes a seal base portion 48 , a plurality of (four in the illustrated example) seal lips 49 a , 49 b , 49 c and 49 d and a weir portion 50 . In addition, in FIG. 2, the sealing member 44 is illustrated in a free state.

The seal base portion 48 includes, among the surfaces of the core metal 43 , the radially outer end portion of the axial inner surface of the upright plate portion 46 , the outer peripheral surface, the axial outer surface, and the inner peripheral surface of the fitting cylinder portion 45 . , the axially outer surface, the inner peripheral surface, and the radially inner end of the axially inner surface of the support plate portion 47 are coupled and fixed to the core metal 43 . A portion of the seal base portion 48 that covers the radially outer end portion of the axially inner surface of the upright plate portion 46 elastically abuts against the axially outer end surface of the outer ring 2 , so that the outer ring 2 and the core bar 43 are sealed. Foreign matter such as muddy water is prevented from entering the internal space 32 from the external space through the portion between and, and the grease enclosed in the internal space 32 is prevented from leaking to the external space.

Each of the seal lips 49 a , 49 b , 49 c , 49 d extends from the seal base 48 toward the sliding ring 33 , and has its distal end in sliding contact with the surface of the sliding ring 33 or in close opposition thereto. In this example, the radially innermost seal lip 49a has its tip portion slidably contacted with the outer peripheral surface of the sliding contact cylindrical portion 35 of the sliding contact ring 33 over the entire circumference. The second seal lip 49b from the inner side in the radial direction has its tip part slidably contacted with the outer peripheral surface (inner side surface in the axial direction) of the slidable contact inclined plate portion 36 of the slidable contact ring 33 over the entire circumference. The third seal lip 49c from the inner side in the radial direction has a distal end portion in sliding contact with the axial inner surface of the sliding contact side plate portion 37 of the sliding contact ring 33 over the entire circumference. The radially outermost seal lip 49 d has its distal end portion closely opposed to the axial inner surface of the radially inner end portion of the mounting plate portion 39 constituting the sliding contact ring 33 over the entire circumference. Thus, a labyrinth seal is formed between the tip portion of the seal lip 49d and the axial inner surface of the mounting plate portion 39. As shown in FIG.

The dam portion 50 protrudes radially outward from a portion of the seal base portion 48 that covers the outer peripheral surface of the upright plate portion 46 and protrudes radially outward beyond the outer peripheral surface of the axially outer end portion of the outer ring 2 . It is arranged in an annular shape. The dam portion 50 dams the muddy water that has flowed axially outward along the outer peripheral surface of the outer ring 2 , so that the muddy water flows between the axially outer end portion of the seal lip 49 d and the radially inner side of the mounting plate portion 39 . to prevent it from entering between the ends of the

The bearing cap 7 is made of a metal plate and has a cylindrical shape with a bottom. The bearing cap 7 is attached to the axially inner end of the outer ring 2 by internally fitting the cylindrical axially outer portion to the axially inner end of the outer ring 2 with an interference fit.

According to the hub unit bearing of this embodiment having the above configuration, axial displacement of the sliding contact ring 33 with respect to the hub 3 can be suppressed.

That is, in the structure of this example, unlike the conventional structure described above, the configuration in which the sliding contact ring is supported by the hub 3 by fitting the sliding contact ring on the shoulder portion 24 of the hub 3 is not adopted. The peripheral portion of the through hole 41 of the sliding contact ring 33 is axially sandwiched between the axial inner surface of the rotary flange 12 and the axial outer surface of the head portion 16 of the hub bolt 5, so that the sliding contact ring 33 is brought into sliding contact with the hub 3. A configuration for supporting the ring 33 is adopted. For this reason, even if the axial dimension of the shoulder portion 24 is small, the peripheral portion of the through hole 41 of the sliding contact ring 33 is located between the axial inner surface of the rotary flange 12 and the axial outer surface of the head portion 16 of the hub bolt 5 . Axial displacement of the sliding contact ring 33 with respect to the hub 3 can be suppressed by being sandwiched between them in the axial direction.

As described above, in the structure of the present embodiment, axial displacement of the sliding contact ring 33 with respect to the hub 3 can be suppressed. It is possible to suppress changes in the directional interference and the axial interference of the seal lip 49c with respect to the axial inner surface of the sliding contact side plate portion 37 of the sliding contact ring 33 . As a result, the sealing torque and sealing performance of the seal lips 49b, 49c can be stabilized.

In addition, in the structure of this example, the fitting cylinder portion 40 constituting the radially outer end portion of the sliding contact ring 33 is loosely fitted to the small diameter portion 21 of the outer peripheral surface of the rotary flange 12 without radial play. While being externally fitted, each of the sliding contact cylindrical portion 35, the sliding contact inclined plate portion 36, and the stepped plate portion 38, which constitute the radially inner portion of the sliding contact ring 33, is radially moved with respect to the surface of the hub 3. It adopts a configuration in which they are separated from each other (not in contact with each other in the radial direction). For this reason, the fitting cylinder portion 40 is externally fitted to the small diameter portion 21 with a clearance fit without radial rattle. The dimensional accuracy required for the sliding contact ring 33 can be kept low compared to the case where one is brought into contact with the surface of the hub 3 in the radial direction.

In addition, in the structure of this example, while the axially outer surface of the mounting plate portion 39 constituting the radially outer portion of the sliding contact ring 33 is brought into contact with the axially inner surface of the thin portion 19 of the rotary flange 12, Each of the sliding inclined plate portion 36, the sliding contact side plate portion 37, and the step plate portion 38, which constitute the radially inner portion of the sliding contact ring 33, includes the axial inner surface of the thick portion 18 of the rotary flange 12. A configuration is adopted in which they are axially separated from the surface of the hub 3 (not in contact with each other in the axial direction). For this reason, the axially outer side surface of the mounting plate portion 39 is brought into contact with the axially inner side surface of the thin portion 19, and at least one of the sliding contact inclined plate portion 36, the sliding contact side plate portion 37, and the stepped plate portion 38 is provided. The dimensional accuracy required for the sliding contact ring 33 can be kept lower than in the case of adopting a configuration in which the contact ring 33 is brought into contact with the surface of the hub 3 in the axial direction.

In addition, in the structure of this example, the fitting cylinder portion 40 that constitutes the radially outer end portion of the sliding contact ring 33 is a large-diameter portion adjacent to the axially outer side of the small-diameter portion 21 on the outer peripheral surface of the rotary flange 12 . It does not protrude radially outward beyond the portion 22 . For this reason, when the hub unit bearing 1 is transported, the fitting cylindrical portion 40 may be damaged by hitting a surrounding object, or when the outer peripheral surface of the rotary flange 12 is used for centering the braking rotor, the fitting may be damaged. It is possible to prevent the cylindrical part 40 from becoming an obstacle.

[Second example of embodiment]
A second example of the embodiment of the invention will be described with reference to FIG.

In the structure of this example, the locking groove 23a provided on the axially inner side surface of the rotating flange 12a is formed on the axially inner side surface of the thick portion 18 of the rotating flange 12a. The O-ring 42a locked in the locking groove 23a is elastically compressed between the bottom surface of the locking groove 23a and the axial outer surface of the sliding contact side plate portion 37 of the sliding contact ring 33a. In the structure of this example, the position where the O-ring 42a is installed in the portion between the hub 3 and the sliding contact ring 33a is closer to the internal space 32 than in the structure of the first example of the embodiment. The amount of grease existing in 32 that can enter the portion between hub 3 and sliding contact ring 33a can be reduced.

In addition, in the structure of this example, the sliding contact inclined plate portion 36 a that constitutes the sliding contact ring 33 a has an arc-shaped cross-sectional shape that is inclined in the direction along the corner R portion 25 of the hub 3 . In such a structure of this example, the size of the gap existing between the slidable inclined plate portion 36a and the corner R portion 25 is smaller than that of the structure of the first example of the embodiment. From this aspect as well, the amount of grease existing in the internal space 32 that can enter the portion between the hub 3 and the sliding contact ring 33a can be reduced.
Other configurations and effects are the same as those of the first embodiment.

[Third example of embodiment]
A third example of the embodiment of the invention will be described with reference to FIG.

In the structure of this example, the rotating flange 12b does not have a locking groove for locking an O-ring on its axially inner side surface. In the structure of this example, the O-ring 42b is elastically formed between the stepped portion 20 provided in the radially intermediate portion of the axial inner surface of the rotary flange 12b and the inner peripheral surface of the stepped portion 38 of the sliding contact ring 33. effectively compressed. In the structure of this example, the position where the O-ring 42b is installed in the portion between the hub 3 and the sliding contact ring 33 is closer to the internal space 32 than in the structure of the first example of the embodiment. The amount of grease existing in 32 that can enter the portion between hub 3 and sliding contact ring 33 can be reduced. Moreover, since it is not necessary to form a locking groove in the rotating flange 12b, the processing cost can be suppressed.
Other configurations and effects are the same as those of the first embodiment.

[Fourth example of embodiment]
A fourth example of the embodiment of the invention will be described with reference to FIG.

In the structure of this example, an annular seal member 52 is adhered (vulcanized) to the inner peripheral surface of the step plate portion 38 of the sliding contact ring 33 over the entire circumference. With the slide ring 33 attached to the hub 3, the seal member 52 is elastically pressed against the stepped portion 20 of the rotary flange 12b. It is elastically compressed between the peripheral surface and the stepped portion 20 of the rotary flange 12b. In the structure of this example, since the sealing material 52 is adhered to the inner peripheral surface of the step plate portion 38 of the sliding contact ring 33, the work of installing the sealing material 52 between the hub 3 and the sliding contact ring 33 is facilitated. can be done
Other configurations and effects are the same as those of the first embodiment.

[Fifth example of embodiment]
A fifth example of the embodiment of the present invention will be described with reference to FIG.

In the structure of this example, the stepped portion 20a provided at the radially intermediate portion of the axially inner surface of the rotary flange 12c is configured by a cylindrical surface facing radially outward. A stepped plate portion 38a provided in a radially intermediate portion of the sliding contact ring 33b is configured in a cylindrical shape. The sliding contact ring 33b does not have the fitting tube portion 40 (see FIG. 2) at the radially outer end. In the structure of this embodiment, the stepped plate portion 38a of the sliding ring 33b is fitted onto the stepped portion 20a of the rotary flange 12c with a clearance fit that eliminates radial rattle. It regulates the directional position. In this example, the step plate portion 38a corresponds to the radial position restricting portion. In the structure of this example, since the sliding contact ring 33b does not have the fitting cylindrical portion 40 (see FIG. 2), the processing cost of the sliding contact ring 33b can be suppressed.
Other configurations and effects are the same as those of the first embodiment.

[Sixth example of embodiment]
A sixth example of the embodiment of the present invention will be described with reference to FIG.

In the structure of this example, the sliding contact ring 33c does not have the fitting tubular portion 40 (see FIG. 2) at the radially outer end portion. In the structure of this embodiment, the sliding contact cylindrical portion 35 forming the radially inner end portion of the sliding contact ring 33c is externally fitted to the shoulder portion 24 of the hub 3 with a clearance fit without radial play. It regulates the radial position of the sliding contact ring 33 b with respect to the hub 3 . In addition, in this example, the slidable cylindrical portion 35 corresponds to the radial position restricting portion. In the structure of this example, since the sliding contact ring 33c does not have the fitting cylindrical portion 40 (see FIG. 2), the processing cost of the sliding contact ring 33b can be suppressed.
Other configurations and effects are the same as those of the first embodiment.

The structures of the respective embodiments as described above can be appropriately combined and implemented within a range that does not cause contradiction.

The present invention can also be applied to hub unit bearings for drive wheels.

Reference Signs List 1 hub unit bearing 2 outer ring 3 hub 4 ball 5 hub bolt 6 sealing device 7 bearing cap 8a, 8b outer ring raceway 9 stationary flange 10 support hole 11a, 11b inner ring raceway 12, 12a, 12b, 12c rotating flange 13 pilot portion 14 mounting hole 15 Axial portion 16 Head 17 Male threaded portion 18 Thick portion 19 Thin portion 20, 20a Stepped portion 21 Small diameter portion 22 Large diameter portion 23, 23a Locking groove 24 Shoulder 25 Corner R portion 26 Inner ring 27 Hub ring 28 Small diameter stepped portion 29 Crimped portion 30 Step surface 31 Cage 32 Internal space 33, 33a, 33b, 33c Sliding contact ring 34 Seal ring 35 Sliding cylindrical portion 36, 36a Sliding inclined plate portion 37 Sliding side plate portion 38, 38a Step plate portion 39 Mounting Plate portion 40 Fitting cylinder portion 41 Through hole 42, 42a, 42b O-ring 43 Core metal 44 Sealing material 45 Fitting cylinder portion 46 Standing plate portion 47 Supporting plate portion 48 Seal base portion 49a, 49b, 49c, 49d Seal lip 50 Weir Part 51 Serration part 52 Sealing material

Claims (4)

an outer ring having a double-row outer ring raceway on its inner peripheral surface;
a hub having a double-row inner ring raceway on its outer peripheral surface, and a rotating flange projecting radially outward from a portion located axially outside the outer ring;
The rotating flange has a thick portion provided radially inward and a mounting portion provided radially outward, which is smaller in axial dimension than the thick portion and penetrates in the axial direction at a plurality of locations in the circumferential direction. a thin-walled portion having a hole; and a radially-outwardly-facing edge connecting the radially outer end of the axially inner surface of the thicker portion and the radially inner end of the axially inner surface of the thinned portion. and
a plurality of rolling elements arranged for each row between the double-row outer ring raceway and the double-row inner ring raceway;
a shaft portion press-fitted into the mounting hole from the inner side in the axial direction; a plurality of hub bolts provided adjacent to the inner side in the axial direction of the shaft portion and having a head portion having an outer diameter dimension larger than that of the shaft portion;
A sliding contact ring supported by the hub and a seal ring supported by the outer ring, and an axially outer opening of an internal space existing between an inner peripheral surface of the outer ring and an outer peripheral surface of the hub. and a sealing device that closes the part,
The sliding contact ring has a radial position regulating portion that is fitted onto the outer peripheral surface of the hub without rattling in the radial direction, and a through hole that is provided on the radially outer portion and through which the shaft portion is inserted. The peripheral portion of the through hole is axially sandwiched between the axially inner side surface of the rotary flange and the axially outer side surface of the head, thereby being supported by the hub and radially an inner portion is spaced axially inward from an axial inner surface of the thick portion;
The seal ring has a seal lip in sliding contact with the axial inner surface of the sliding ring.
hub unit bearings. The rotary flange has a small-diameter portion on the outer peripheral surface of the axially inner portion, the outer diameter dimension of which is smaller than that of the portion adjacent to the axially outer side,
The radial position regulating portion is fitted onto the small diameter portion.
A hub unit bearing according to claim 1. The radial position restricting portion is fitted onto the stepped portion,
A hub unit bearing according to claim 1. The radial position restricting portion is fitted onto a portion of the outer peripheral surface of the hub that is axially positioned between the rotary flange and the inner ring raceway in the axially outer row among the double-row inner ring raceways. ing,
A hub unit bearing according to claim 1.

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