JP7649661B2 - Wheel bearing device - Google Patents

Description

The present invention relates to a wheel bearing device.

2. Description of the Related Art Wheel bearing devices that rotatably support wheels have been known in the prior art for use in suspension systems for automobiles and the like.
The wheel bearing device has, for example, a configuration in which a hub ring (inner member) connected to a wheel is rotatably supported on an outer member via rolling elements.
Furthermore, the wheel bearing device is often disposed in a space surrounded mainly by the suspension device, the tire well of the wheel, the brake rotor, etc., and is exposed to the outside.
For this reason, in the wheel bearing device, in order to prevent foreign matter such as muddy water from entering the installation space of the rolling elements from the outside, sealing members are provided at each of the opening ends on the inner and outer sides of the annular space formed between the outer member and the inner member.

Incidentally, in recent years, in addition to improvements in fuel efficiency in vehicles such as automobiles, there has been a demand for sealing members in wheel support bearing assemblies to be more effective at preventing the intrusion of foreign matter than ever before.
Taking this into consideration, for example, Patent Document 1 discloses a wheel support rolling bearing unit (wheel bearing device) that is equipped with a seal ring (sealing member) that is designed to improve the effectiveness of preventing the intrusion of foreign matter without increasing rotational resistance, while also taking into consideration improving fuel efficiency in the vehicle.
Specifically, the above-mentioned sealing member is a sealing member (hereinafter referred to as the "outer side sealing member" as appropriate) provided at the outer opening end of the annular space formed between an outer ring (outer member) and a hub (inner member), and comprises a core bar that is fitted into the outer member, and a sealing material (seal body) that is joined to the core bar, and the sealing body has a plurality of seal lips as well as a labyrinth slip that is located radially outside these seal lips.
The tip end of the labyrinth slip is located radially outward of a step formed on the inner surface of a rotation side flange (wheel mounting flange) provided on the outer side of the inner member, and overlaps radially with the step.
Moreover, the inner periphery of the tip of the labyrinth slip closely faces the outer periphery of the step over the entire circumference, so that an axial labyrinth seal is formed between the inner periphery of the tip and the outer periphery of the step.

JP 2010-210085 A

According to the wheel bearing device in Patent Document 1 mentioned above, a labyrinth slip is additionally provided radially outward of a plurality of seal lips provided on the outer seal member, and since this labyrinth slip is in a non-contact state with the inner member (more specifically, the wheel mounting flange) which rotates relatively to the outer member, it is possible to improve the effect of preventing the intrusion of foreign matter without increasing the rotational resistance.
However, the outer seal member is pressed in axially by a pressing tool so that the core bar fits into the outer member and is attached to the outer member. By providing the labyrinth slip, the pressing surface that can be pressed by the pressing tool becomes a radially narrow annular plane located between the labyrinth slip and the multiple seal lips.

Therefore, when performing the pressing operation to press the outer seal member into the outer member, the tip of the pressing jig must be pressed against the above-mentioned pressing surface, which is narrow in the radial direction. Considering the variation in the external dimensions of the base of the labyrinth slip, the external dimensions of the tip of the pressing jig must be strictly controlled, which is one factor that impairs the ease of attaching the outer seal member to the outer member.

In addition, it was difficult to apply the pressing force from the press-fitting tool evenly across the entire surface of the pressing surface, which was narrow in the radial direction, and it was difficult to perform the press-fitting operation on the outer member while maintaining a coaxial position with the outer member.

Furthermore, since the pressing force applied to the pressing surface by the pressing jig is easily uneven, the outer seal member is easily deformed by the pressing operation, and since the pressing surface is provided on a seal body made of an elastic material, excessive pressing force is applied locally, raising concerns that this could lead to damage to the seal body.

The present invention was made in consideration of the current problems described above, and aims to provide a wheel bearing device that is equipped with an outer seal member that is attached to an outer member and has a labyrinth slip that improves the effect of preventing foreign matter from entering the installation space of the rolling elements, and that allows the outer seal member to be easily pressed into the outer member.

The problem that the present invention aims to solve is as described above, and the means for solving this problem will be explained next.

That is, the wheel bearing device according to the present invention comprises an outer member having a double-row outer raceway surface on its inner circumference, a hub wheel having a small diameter step extending in the axial direction on its outer circumference and a wheel mounting flange disposed on the outer side of the small diameter step, and at least one inner ring press-fitted into the small diameter step of the hub wheel, an inner member having a double-row inner raceway surface on its outer circumference that faces the double-row outer raceway surface, double-row rolling elements accommodated in a rollable manner between the raceway surfaces of the outer member and the inner member, and an outer seal member that closes the outer opening end of the annular space formed by the outer member and the inner member. In the wheel bearing device, the outer seal member has a core metal fitted to the outer member and a seal body made of an elastic body joined to the core metal, and the seal body has a labyrinth slip located radially outward from the fitting surface of the core metal with the outer member and extending axially toward the wheel mounting flange of the hub wheel, an annular pressing surface located radially inward from the base side of the labyrinth slip and consisting of a plane parallel to the outer end face of the outer member, and an annular recessed groove interposed between the labyrinth slip and the pressing surface.

The present invention has the following advantages.
In other words, according to the wheel bearing device of the present invention, the outer seal member, which is attached to the outer member and has a labyrinth slip that improves the effect of preventing foreign matter from entering the installation space of the rolling elements, can be easily pressed into the outer member.

1 is a cross-sectional view showing an overall configuration of a wheel bearing device according to an embodiment of the present invention. 4 is an enlarged cross-sectional view showing a specific configuration of an outer seal member. FIG. FIG. 11 is a chronological diagram showing the state of the press-fitting operation of the outer seal member into the outer ring, in which (a) is an enlarged cross-sectional view showing the state immediately before the press-fitting operation is performed, and (b) is an enlarged cross-sectional view showing the state immediately after the fitting operation is completed. 10 is an enlarged cross-sectional view showing a specific configuration of an outer seal member provided in a wheel support bearing device according to another embodiment. FIG. 10 is an enlarged cross-sectional view showing a specific configuration of an outer seal member provided in a conventional wheel support bearing device. FIG.

Next, an embodiment of the present invention will be described with reference to FIGS.
For convenience, the description in this specification will be based on the inner side and the outer side defined by the directions of the arrows in FIG.
Here, the "inner side" refers to the direction toward the inside of the vehicle body with respect to the wheel bearing device 1 when it is attached to the vehicle body of an automobile or the like.
In addition, the "outer side" means the side opposite the inner side with respect to the wheel bearing device 1 when mounted on the body of an automobile or the like, i.e., the direction of the wheel side that is supported rotatably by the wheel bearing device 1.

In addition, in this specification, the direction parallel to the rotation axis G of the wheel bearing device 1 (see Figure 1) is defined as the "axial direction", the direction perpendicular to the rotation axis G of the wheel bearing device 1 is defined as the "radial direction", and the direction along the arc centered on the rotation axis G of the wheel bearing device 1 is defined as the "circumferential direction".

[Overall configuration of wheel bearing device 1]
First, the overall configuration of a wheel bearing device 1 according to this embodiment will be described with reference to FIG.
The wheel bearing device 1 supports a wheel rotatably in a suspension system of a vehicle such as an automobile.
The wheel bearing device 1 mainly comprises an outer ring 2, a hub ring 3, an inner ring 4, double row (two rows in this embodiment) ball rows 5, 5 which are rolling elements, an inner side seal member 6, and an outer side seal member 7.

The outer ring 2 is an example of an outer member, and supports the hub ring 3 and the inner ring 4 .
The outer ring 2 is made of a substantially hollow cylindrical member, and its inner end is provided with an inner side opening 2a into which an inner side seal member 6 can be fitted, and its outer end is provided with an outer side opening 2b into which an outer side seal member 7 can be fitted.

The inner circumference of the outer ring 2 is provided with double-row (two rows in this embodiment) outer raceways 2c, 2c that are circumferentially annular and spaced apart from each other in the axial direction, and the outer circumference of the outer ring 2 is integrally provided with a flange 2d that can be attached to a knuckle (not shown) of a suspension device.

The hub wheel 3 is a member that constitutes an inner member together with an inner ring 4, and supports a vehicle wheel (not shown) for free rotation.
The hub wheel 3 is made of a substantially solid cylindrical member, and a small diameter step portion 3a that extends in the axial direction is provided on the outer periphery on the inner side.
A wheel mounting flange 3b to which the wheel can be attached is integrally provided at the outer end of the hub wheel 3 so as to expand in an arc shape in a radial cross section.

A plurality of hub bolts 3c, 3c . . . for fastening the wheel to the hub 3 are press-fitted into the wheel mounting flange 3b.
Further, on the outer periphery on the outer side of the hub wheel 3, a circumferentially annular inner raceway surface 3d is provided opposite the above-mentioned outer raceway surface 2c on the outer side.

An inner ring 4 is press-fitted into the small diameter step portion 3 a of the hub wheel 3 .
The inner ring 4 is a component that constitutes the inner member together with the hub ring 3 and is made of a substantially hollow cylindrical component. On its outer periphery, a circumferentially annular inner raceway surface 4a is provided opposite the above-mentioned inner-side outer raceway surface 2c.

The inner ring 4 is fixed to the hub wheel 3 by plastically deforming (crimping) the end portion on the inner side of the hub wheel 3 radially outward.
The method of fixing the inner ring 4 to the hub wheel 3 is not limited to this embodiment, and for example, a fastening member such as a nut may be screwed and fixed at the inner end of the hub wheel 3.

In this way, in the inner member formed by the hub wheel 3 and the inner ring 4, the inner raceway surface 4a provided on the inner ring 4 is disposed at the inner end, and the inner raceway surface 3d provided on the hub wheel 3 is disposed at the outer end, and these double row (two rows in this embodiment) inner raceway surfaces 3d and 4a are disposed opposite the two rows of outer raceway surfaces 2c and 2c provided on the outer ring 2 described above.

The two rows of balls 5 , 5 support an inner member consisting of the hub ring 3 and the inner ring 4 so as to be rotatable relative to the outer ring 2 .
Each ball row 5 is made up of a plurality of balls 5a, 5a . . . arranged in an annular manner, and a cage 5b that holds these balls 5a, 5a .

These two rows of balls 5 are each housed in a rollable manner in two installation spaces Q1, Q1 formed between two rows of outer raceways 2c, 2c provided at the inner and outer ends of the outer ring 2, and two rows of inner raceways 3d, 4a provided at the inner and outer ends of the inner member (hub ring 3 and inner ring 4).

As described above, the wheel bearing device 1 in this embodiment is configured as a double-row angular ball bearing including the outer ring 2, the hub ring 3, the inner ring 4, and the two rows of balls 5.
The configuration of the wheel bearing device 1 is not limited to this embodiment, and may be configured as a double row tapered roller bearing using a tapered roller row instead of the ball row 5, for example.

The inner seal member 6 closes the inner open end of the annular space Q2 formed by the outer ring 2 and the inner member (the hub ring 3 and the inner ring 4).
The inner seal member 6 includes a substantially cylindrical seal plate 6a and a substantially cylindrical slinger 6b.

The seal plate 6a is formed of a steel plate or the like that is bent into an annular shape into an L-shape when viewed in the circumferential direction, and a plurality of seal lips made of, for example, synthetic rubber are vulcanized and bonded to the seal plate 6a.
Similarly to the sealing plate 6a, the slinger 6b is also made of a steel plate or the like that is bent into an annular shape in an L-shape when viewed in the circumferential direction.

The seal plate 6a is fitted into the inner side opening 2a of the outer ring 2 with the seal plate 6a being coaxial with the outer ring 2 and with the multiple seal lips facing the inner side.
The slinger 6b is fitted onto the outer periphery of the inner ring 4 coaxially with the inner ring 4 and on the inner side of the seal plate 6a so as to face the seal plate 6a.
As a result, the inner seal member 6 is configured as a pack seal consisting of the seal plate 6a and the slinger 6b.

The outer side sealing member 7 seals the outer side opening end (more specifically, the outer side opening 2b of the outer ring 2) in the annular space Q2 formed by the outer ring 2 and the inner member (the hub ring 3 and the inner ring 4).
The configuration of the outer seal member 7 will be described in detail later.

As described above, the wheel bearing device 1 in this embodiment is configured as a wheel bearing device of a third generation structure in which the inner raceway surface 3d on which the outer ball row 5 can roll is formed directly on the outer periphery of the hub wheel 3, but is not limited to this. For example, the wheel bearing device may be configured as a wheel bearing device of a second generation structure in which a pair of inner rings are coaxially press-fitted and fixed to the outer periphery of the hub wheel, and an inner raceway surface on which the ball row can roll is formed directly on the outer periphery of each inner ring.

[Configuration of outer seal member 7]
Next, the configuration of the outer seal member 7 will be described in detail with reference to FIGS.
As shown in FIG. 2, the outer seal member 7 includes a core metal 71 that is fitted onto the outer ring 2, and a seal body 72 made of an elastic material that is joined to the core metal 71, and the like.

The core wire 71 is formed by pressing a circular steel plate made of, for example, a ferritic stainless steel plate (such as JIS standard SUS430 series), an austenitic stainless steel plate (such as JIS standard SUS304 series), or a dust-proof treated cold-rolled steel plate (JIS standard SPCC series, etc.).
The core metal 71 is mainly composed of a cylindrical portion 71a, a bent portion 71b, a disk portion 71c, and a flange portion 71d.

The cylindrical portion 71a extends from the outer end of the outer ring 2 toward the inner side, and its outer diameter is set to be approximately equal to the inner diameter of the outer opening 2b of the outer ring 2.

The core bar 71 is fitted into the outer opening 2b of the outer ring 2 (i.e., the outer end of the annular space Q2 (see Figure 1) described above, which is the inner circumference of the outer ring 2) via the cylindrical portion 71a.
In other words, the outer periphery of the cylindrical portion 71 a forms the fitting surface of the core metal 71 with the outer ring 2 , and the inner periphery of the outer side opening 2 b forms the fitted surface of the outer ring 2 with the core metal 71 .

The bent portion 71b is bent radially inward from the inner end of the cylindrical portion 71a, and then extends axially toward the outer side to a position midway along the cylindrical portion 71a.
Furthermore, the disk portion 71c extends radially inward from the outer end of the bent portion 71b to the vicinity of the outer periphery of the hub wheel 3 (more specifically, the shaft circumferential surface portion 31b described later).

Furthermore, the flange portion 71d extends radially outward from the outer end of the cylindrical portion 71a.
In addition, the radially outer end of the flange portion 71d is located radially outward compared to the outer peripheral surface 2e at the outer end of the outer ring 2, and the radially outer end of the flange portion 71d is provided with an outer edge portion 71e extending toward the inner side while having a predetermined gap with the outer peripheral surface 2e.

The sealing body 72 is formed of an elastic body made of synthetic rubber such as NBR (acrylonitrile butadiene rubber), HNBR (hydrogenated acrylonitrile butadiene rubber) which has excellent heat resistance, EPDM (ethylene propylene rubber), ACM (polyacrylic rubber) which has excellent heat resistance and chemical resistance, FKM (fluororubber), or silicone rubber, and is integrally joined to the core metal 71 by vulcanization adhesion.
In addition, the sealing body 72 is composed of a radial lip 72a, an inner axial lip 72b, and an outer axial lip 72c provided on the disc portion 71c of the core bar 71, a labyrinth lip 72d provided on the flange portion 71d of the core bar 71, and a dam portion 72e provided on the outer edge portion 71e of the core bar 71.

The radial lip 72a is provided at the radially inner end of the disk portion 71c and is formed so as to extend toward the inner side and radially inward.
The inner axial lip 72b is provided radially outward from the radial lip 72a and is formed so as to extend toward the outer side.
Furthermore, the outer axial lip 72c is provided radially outward with respect to the radial lip 72a and the inner axial lip 72b, and is formed so as to extend toward the outer side and radially outward.

The radial lip 72a, inner axial lip 72b, and outer axial lip 72c are arranged coaxially with each other and are in sliding contact with the stepped portion 31 of the hub wheel 3.

Here, the step portion 31 refers to a portion provided at the base end of the wheel mounting flange 3 b of the hub wheel 3 that protrudes towards the inner side.
Specifically, the step portion 31 is composed of a flat portion 31a consisting of a plane perpendicular to the rotation axis G (see Figure 1), a circumferential shaft surface portion 31b located radially inside the flat portion 31a and extending coaxially with the rotation axis G, and an arc surface portion 31c that smoothly connects the flat portion 31a and the circumferential shaft surface portion 31b.
Additionally, an outer peripheral surface portion 31d of the step portion 31 is inclined at a predetermined curvature, and smoothly connects from the outer edge of the flat portion 31a to a bearing surface 31e of the hub bolt 3c (see FIG. 1).

The tip of the radial lip 72a comes into contact with the axial surface portion 31b of the step portion 31 via an oil film of grease, which is a lubricant, and the tip of the inner axial lip 72b comes into contact with the arc surface portion 31c of the step portion 31 via said oil film, and further, the tip of the outer axial lip 72c comes into contact with the flat portion 31a of the step portion 31 via said oil film.
In this way, the outer seal member 7 is configured to be able to slide relative to the hub wheel 3 by the radial lip 72a, the inner axial lip 72b, and the outer axial lip 72c contacting the step portion 31 via an oil film of grease.

The labyrinth lip 72d is located radially outward of the outer axial lip 72c and radially outward of the outer periphery of the cylindrical portion 71a that constitutes the above-mentioned mating surface, and is formed so as to extend axially toward the outer side, i.e., toward the wheel mounting flange 3b of the hub wheel 3.

Specifically, the labyrinth slip 72d is formed so as to be slightly inclined radially outward with respect to the rotation axis G and extend toward the outer side.
On the other hand, a circular recess 31f recessed toward the outer side is formed coaxially with the rotation axis G on the flat surface portion 31a of the step portion 31 of the hub wheel 3.

The labyrinth slip 72d is disposed so that its tip is positioned in a non-contact state within the recess 31f.
That is, the labyrinth lip 72d is positioned so as to enclose the above-mentioned radial lip 72a, inner axial lip 72b, and outer axial lip 72c radially inward, while filling the gap between the outer end face of the outer ring 2 and the flat portion 31a of the step portion 31 in the hub wheel 3.
As a result, for example, foreign matter (muddy water, dust, etc.) moving toward the outer axial lip 72c from the outside is received by the labyrinth slip 72d, guided circumferentially along the outer periphery of the labyrinth slip 72d, and then falls directly, thereby improving the effect of preventing foreign matter from entering the annular space Q2 in the wheel bearing device 1 without increasing the rotational resistance.

The dam portion 72e is provided in a generally rectangular shape when viewed in circumferential cross section, and is disposed at the outer end of the outer ring 2 so as to protrude radially outward while being in contact with the outer circumferential surface 2e.
The dam portion 72e is provided on the core metal 71 so as to cover the radially outer end of the flange portion 71d as well as the outer edge portion 71e.
As a result, for example, foreign matter such as muddy water flowing along the outer peripheral surface 2e of the outer ring 2 into the labyrinth slip 72d is blocked by the dam portion 72e, thereby more effectively preventing foreign matter from entering the annular space Q2 in the wheel bearing device 1.

Incidentally, a pressing surface 72f, which is a flat surface perpendicular to the rotation axis G, is provided between the outer axial lip 72c and the labyrinth lip 72d.
More specifically, the pressing surface 72 f is located on the radially inner root side of the labyrinth slip 72 d and is formed in an annular shape consisting of a flat surface parallel to the outer end face 2 f of the outer ring 2 .

As shown in FIG. 3A, the inner diameter R1 of the pressing surface 72f is set to be larger than the outer diameter Ra1 at the tip of the outer axial lip 72c (R1>Ra1), and the outer diameter R2 of the pressing surface 72f is set to be smaller than the inner diameter Ra2 at the base of the labyrinth lip 72d (R2<Ra2).
In other words, when viewed in the axial direction, the pressing surface 72f is arranged so as not to overlap with the outer axial lip 72c and the labyrinth lip 72d.

As shown in FIG. 3(b), when the outer seal member 7 is attached to the outer end of the outer ring 2, the tip Ja of the press-fitting jig J is pressed against the pressing surface 72f, and the press-fitting jig J presses the cylindrical portion 71a of the core metal 71 into the outer opening 2b of the outer ring 2.

Here, as shown in FIG. 5, in a conventional wheel bearing device 101, when a labyrinth slip 172d is provided on the sealing body 172 of the outer sealing member 107, a root portion on the radially inner side of the labyrinth slip 172d is formed as an arc-shaped corner portion 172g in a circumferential cross-sectional view, which smoothly connects to the pressing surface 172f.
Therefore, the pressing surface 172f is formed in a region between the outer axial lip 172c and the labyrinth lip 172d excluding the corner portion 172g, and is an annular flat surface that is narrow in the radial direction.

As a result, for example, when performing the above-mentioned pressing operation, the tip Ja of the pressing jig J must be pressed against the radially narrow pressing surface 172f, and considering the variation in the external dimensions of the base of the labyrinth slip 172d (i.e., the corner 172g), the external dimensions of the tip Ja must be strictly controlled to avoid interference with the corner 172g, which is one factor that impairs the ease of mounting the outer side seal member 107 to the outer side end 102b of the outer ring 102.

As shown in FIG. 2, this embodiment has a ring-shaped recessed groove 72g located between the labyrinth slip 72d and the pressing surface 72f at the radially inner base side of the labyrinth slip 72d.

In this way, by performing recess processing consisting of a circular ring-shaped groove 72g without providing an arc-shaped corner 172g when viewed in circumferential cross section, as in the conventional wheel bearing device 101, it is possible to ensure a radially wider pressing surface 72f than in the conventional outer side seal member 107, without having to consider the corner 172g.
Furthermore, for example, when performing the above press-fitting operation, unlike the conventional wheel bearing device 101, there is no need to avoid interference between the tip portion Ja of the press-fitting jig J and the corner portion 172g.

Therefore, even if the variation in the external dimensions at the base of the labyrinth slip 72d is taken into consideration, there is less need to strictly control the external dimensions of the tip portion Ja of the press-fitting jig J compared to the conventional outer seal member 107, and the ease of attachment of the outer seal member 7 to the outer end portion 2b of the outer ring 2 can be improved.

In addition, compared to the conventional outer seal member 107 (see FIG. 5), a wider pressing surface 72f can be secured in the radial direction, making it easier to apply the pressing force from the pressing jig J (see FIG. 3) evenly across the entire surface of the pressing surface 72f, and the pressing operation into the outer ring 2 can be easily performed while maintaining a coaxial position with the outer ring 2.

Furthermore, since the pressing force applied to the pressing surface 72f by the pressing jig J is unlikely to be biased, deformation of the outer seal member 7 caused by the pressing operation is prevented, and damage to the seal body 72 made of an elastic material due to excessive pressing force being applied locally can be prevented.

In this embodiment, the recessed groove 72g is formed in a generally rectangular shape in a circumferential cross section that is recessed in the axial direction toward the inner side, but is not limited to this.
For example, as shown in FIG. 4, a recessed groove 272g recessed toward the inner side and having a circular shape in a circumferential cross section may be provided in place of the recessed groove 72g.

However, in this embodiment, the groove 72g (see FIG. 2) is formed in an approximately rectangular shape recessed in the axial direction when viewed in circumferential cross section, and thus, unlike the groove 272g which is circular when viewed in circumferential cross section, it is possible to avoid recessing in the radial direction (more specifically, radially outward).
Therefore, in FIG. 2, the thickness of the base portion of the labyrinth slip 72d is not reduced by the recessed groove 72g, and the rigidity of the base portion of the labyrinth slip 72d can be sufficiently maintained.

Also, as shown in FIG. 3(a), the outer edge of the pressing surface 72f is positioned radially outward from the mating surface of the core bar 71, i.e., the outer periphery of the cylindrical portion 71a, and the inner edge of the pressing surface 72f is positioned radially inward from the mating surface of the core bar 71 (the outer periphery of the cylindrical portion 71a).

With this configuration, the pressing force applied by the pressing jig J through the pressing surface 72f can be received by the mating surface (the outer periphery of the cylindrical portion 71a) of the core wire 71, which has a relatively high rigidity formed by bending processing, so that deformation of the outer seal member 7 due to the pressing operation can be more effectively prevented.
In addition, it becomes easier to apply the pressing force from the pressing jig J more reliably and evenly across the entire pressing surface 72f, and the pressing operation into the outer ring 2 can be performed more stably while maintaining a coaxial posture with the outer ring 2.

Although the embodiments of the present invention have been described above, the present invention is in no way limited to these embodiments, which are merely examples, and it goes without saying that the present invention can be embodied in various other forms without departing from the spirit of the present invention. The scope of the present invention is indicated by the claims, and further includes the equivalent meanings set forth in the claims, and all modifications within the scope of the claims.

1 Wheel bearing device 2 Outer ring (outer member)
2b Outer side opening 2c Outer raceway surface 2d Flange 2f Outer side end face of outer ring 3 Hub ring (inner member)
3a Small diameter step portion 3b Wheel mounting flange 3d Inner raceway surface 4 Inner ring (inner member)
4a Inner raceway surface 5 Row of balls (rolling elements)
7 Outer seal member 71 Core metal 71a Cylindrical portion 72 Seal body 72d Labyrinth slip 72f Pressing surface 72g Groove 272g Groove Q2 Annular space

Claims (2)

an outer member having a double row outer raceway surface on an inner periphery thereof;
an inner member including a hub wheel having a small diameter step extending in the axial direction on an outer periphery and a wheel mounting flange disposed on the outer side of the small diameter step, and at least one inner ring press-fitted into the small diameter step of the hub wheel, the inner member having a double row inner raceway surface on an outer periphery facing the double row outer raceway surface;
a double row of rolling elements rollably accommodated between the raceway surfaces of the outer member and the inner member;
an outer-side seal member that closes an outer-side opening end of an annular space formed by the outer member and the inner member,
The outer seal member is
a core bar fitted to the outer member;
a seal body made of an elastic material bonded to the core metal,
The seal body is
a labyrinth slip located radially outward of a fitting surface of the core metal with the outer member and extending axially toward the wheel mounting flange of the hub wheel;
a pressing surface having an annular shape and formed as a flat surface that is located on a root side on the radial inside of the labyrinth slip and is parallel to an end surface on an outer side of the outer member;
a circular groove interposed between the labyrinth slip and the pressing surface and continuous with the labyrinth slip and the pressing surface ;
The recessed groove is formed to be recessed in the axial direction .
A wheel bearing device comprising: an outer edge of the pressing surface is located radially outward from the fitting surface of the core bar, and an inner edge of the pressing surface is located radially inward from the fitting surface of the core bar.
2. A wheel bearing device according to claim 1, wherein the wheel bearing device is a bearing for a wheel.

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