Wheel bearing device

Abstract

To provide a bearing device for a wheel which enables improvement of foreign object entry prevention effect on an installation space of rolling elements and can maintain stable seal performance.SOLUTION: An annular groove part 3e which is coaxial with a hub ring 3 is provided on an inner side surface of a wheel attaching flange 3b in the hub ring 3. An outer side seal member 8 has a labyrinth lip 82d which is formed by an elastic body, extends in an axial direction toward the wheel attaching flange 3b, and forms a labyrinth seal by inserting its tip into the annular groove part 3e in a manner that the tip does not contact with the annular groove part 3e. The hub ring 3 has a cutout part 3f which is formed toward the radial outer side relative to the annular groove part 3e and is open to the outside.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a wheel bearing device. [Background technology]

[0002] 2. Description of the Related Art Wheel bearing devices that rotatably support wheels in suspension systems for automobiles and the like have been known. 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 order to prevent foreign matter such as muddy water from entering the installation space of the rolling elements from the outside, the wheel bearing device is provided with sealing members 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.

[0003] Incidentally, in recent years, there has been a demand for seal members in wheel bearing devices that are more effective at preventing the intrusion of foreign matter than ever before. Taking this into consideration, for example, Patent Document 1 discloses a technology in which a ring-shaped recess (annular groove) is provided coaxially with the hub wheel on the inner side of the rotating flange (wheel mounting flange) of the hub wheel, and the tip of the radially outermost side lip (outer axial lip) of a seal ring (outer seal member) arranged on the outer side is inserted into the annular groove without contacting it, to form a labyrinth seal. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2013-61048 A Summary of the Invention [Problem to be solved by the invention]

[0005] According to the wheel bearing device in Patent Document 1 mentioned above, a labyrinth seal formed by an annular groove portion provided in the wheel mounting flange of the hub wheel and the tip portion of the outer axial lip inserted into the annular groove portion prevents foreign matter such as muddy water from entering the installation space of the rolling elements from the outside, improving the effect of preventing the intrusion of foreign matter. However, on the other hand, once a foreign object enters the annular groove, it is very difficult to expel the foreign object to the outside of the annular groove. As a result, foreign matter gradually accumulates in the annular groove, and the accumulated foreign matter accelerates wear of the lip portion of the outer seal member (in this example, the outer axial lip), which may result in the outer seal member not being able to maintain its sealing performance (the ability to prevent foreign matter from entering) for the specified period of use.

[0006] The present invention has been made in consideration of the current problems described above, and has an object to provide a wheel bearing device that improves the effect of preventing foreign matter from entering the installation space of the rolling elements and can maintain stable sealing performance. [Means for solving the problem]

[0007] The problem to be solved by the present invention has been described above, and the means for solving this problem will now be described.

[0008] 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 ring of an annular space formed by the outer member and the inner member. In the wheel bearing device, the wheel hub has an annular groove portion coaxial with the hub on an inner side of the wheel mounting flange, the outer seal member is made of an elastic body, extends axially toward the wheel mounting flange, and has a labyrinth slip that forms a labyrinth seal by inserting a tip portion of the outer seal member into the annular groove portion in a non-contact state, and the hub has a notch portion that is formed radially outward from the annular groove portion and opens to the outside. The cutout portion is formed in a trapezoidal shape whose cross-sectional shape gradually decreases toward the radially outer side when viewed in the axial direction. It is characterized by: Effect of the Invention

[0009] The present invention has the following advantages. That is, the wheel bearing device according to the present invention can improve the effect of preventing foreign matter from entering the installation space of the rolling elements, and can maintain stable sealing performance. [Brief description of the drawings]

[0010] [Figure 1] 1 is a cross-sectional view showing an overall configuration of a wheel bearing device according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a front view showing a specific configuration of a hub wheel as viewed from the inner side in the axial direction. [Diagram 3] FIG. 11 is a diagram showing a specific configuration of a hub wheel provided in a wheel bearing device according to a second embodiment, and is a front view viewed from the inner side in the axial direction. [Figure 4]13A is a front view from the inner axial side when multiple cutouts are provided at positions that are out of phase with the positions at which multiple hub bolts are arranged, and FIG. 13B is a front view from the inner axial side when multiple cutouts are provided at positions that are in the same phase as the positions at which multiple hub bolts are arranged. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] 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 (101, 201) in a state in which it is mounted on the vehicle body of an automobile or the like. In addition, the "outer side" means the side opposite to the inner side with respect to the wheel bearing device 1 (101, 201) when mounted on the body of an automobile or the like, i.e., the direction of the wheel side supported for free rotation by the wheel bearing device 1 (101, 201).

[0012] In addition, in this specification, the direction parallel to the rotation axis G (see Figure 1) of the wheel bearing device 1 (101, 201) is defined as the "axial direction", the direction perpendicular to the rotation axis G of the wheel bearing device 1 (101, 201) is defined as the "radial direction", and the direction along the arc centered on the rotation axis G of the wheel bearing device 1 (101, 201) is defined as the "circumferential direction".

[0013] [Configuration of wheel bearing device 1 (first embodiment)] First, the configuration of a wheel bearing device 1 in the first embodiment will be described with reference to FIGS. The wheel bearing device 1 rotatably supports a wheel in a suspension system of a vehicle such as an automobile. As shown in FIG. 1, the wheel bearing device 1 mainly comprises an outer ring 2, a hub ring 3, an inner ring 4, double-row (two-row in this embodiment) ball rows 5·5 which are rolling elements, a pulsar ring 6, a bearing cap 7, and an outer seal member 8.

[0014] 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 consists of a substantially hollow cylindrical member, the inner end of which is provided with an inner side opening 2a into which a bearing cap 7 can be fitted, and the outer end of which is provided with an outer side opening 2b into which an outer side seal member 8 can be fitted.

[0015] The inner circumference of the outer ring 2 is provided with double-row (two-row in this embodiment) outer raceway surfaces 2c·2c that are annular in the circumferential direction and coaxially spaced apart from each other in the axial direction, and the outer circumference of the outer ring 2 is integrally provided with a flange (also not shown) that can be attached to a knuckle (not shown) of a suspension device.

[0016] The hub wheel 3 is a member that constitutes an inner member together with the inner ring 4, and supports a vehicle wheel (not shown) for free rotation. The hub ring 3 is made of medium to high carbon steel such as S53C containing 0.40 to 0.80 wt % carbon and has a generally solid cylindrical shape, and is provided on the outer periphery on the inner side with a reduced diameter step portion 3a extending in the axial direction. A wheel mounting flange 3b, to which the wheel can be mounted, 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.

[0017] A plurality of hub bolts 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.

[0018] The hub wheel 3 is induction hardened from the small diameter step 3a through the inner raceway surface 3d to a step portion 31 described later, and is hardened so that the surface hardness is in the range of 58 to 64 HRC.

[0019] 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.

[0020] 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 to the inner end of the hub wheel 3.

[0021] 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 arranged at the inner end, and the inner raceway surface 3d provided on the hub wheel 3 is arranged at the outer end, and these double row (two rows in this embodiment) inner raceway surfaces 3d·4a are arranged opposite the two rows of outer raceway surfaces 2c·2c provided on the outer ring 2 described above.

[0022] 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 arranged in an annular manner and a cage 5b that holds the balls 5a so that they can roll freely.

[0023] These two rows of balls 5·5 are each freely rollable within two installation spaces Q1·Q1 formed between two rows of outer raceways 2c·2c provided at the inner and outer ends, respectively, of the outer ring 2 and two rows of inner raceways 3d·4a provided at the inner and outer ends, respectively, of the inner member (hub ring 3 and inner ring 4).

[0024] 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 5·5. 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.

[0025] The pulser ring 6, together with a magnetic sensor (not shown) provided on the bearing cap 7, detects the rotation speed of the wheel. The pulsar ring 6 is composed of a support ring 61 formed in an annular shape, a magnetic encoder 62 joined to the support ring 61, and the like.

[0026] The support ring 61 is formed, for example, by pressing a ferromagnetic steel plate, so as to have an approximately L-shaped cross-section when viewed in the circumferential direction, and has a cylindrical fitting portion 61a that fits into the inner ring 4, and a standing portion 61b that extends radially outward from the inner end of the fitting portion 61a. On the other hand, the magnetic encoder 62 is configured as a rotary encoder for detecting the rotational speed of a wheel, in which magnetic powder such as ferrite is mixed into an elastomer such as rubber, so that N and S poles are magnetized alternately and at equal intervals in the circumferential direction, thereby changing the magnetic characteristics.

[0027] The magnetic encoder 62 is joined to the support ring 61 by vulcanization adhesion on the inner side surface of the standing plate portion 61b of the support ring 61.

[0028] The bearing cap 7 closes the open end on the inner side 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 bearing cap 7 is made of, for example, a cylindrical synthetic resin with a bottom, and is fitted and fixed into the inner side opening 2a of the outer ring 2 to close the inner periphery of the outer ring 2 on the inner side.

[0029] A magnetic sensor (not shown) is attached to the bearing cap 7 so as to face the magnetic encoder 62 of the pulsar ring 6 across a specified air gap, and the rotational speed of the wheel is detected by detecting changes in the magnetic properties of the magnetic encoder 62 using the magnetic sensor.

[0030] In this embodiment, the bearing cap 7 is provided to close the open end on the inner side of the annular space Q2, but the present invention is not limited to this. For example, an inner side seal member consisting of a pack seal constituted by a seal plate made of an annular steel plate bent so as to have an approximately L-shaped cross section when viewed in the circumferential direction and having a plurality of seal lips vulcanization-bonded thereto, and a slinger made of an annular steel plate bent so as to have an approximately L-shaped cross section when viewed in the circumferential direction and having a magnetic encoder vulcanization-bonded thereto, may be provided in place of the pulsar ring 6 and bearing cap 7 in this embodiment.

[0031] The outer side sealing member 8 seals the outer side opening end (more specifically, the outer side opening 2b of the outer ring 2) 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 outer seal member 8 has a core metal 81 that is fitted onto the outer ring 2, and a seal body 82 made of an elastic body that is joined to the core metal 81, and the like.

[0032] The core bar 81 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 (JIS standard SUS304 series), or a dustproof treated cold rolled steel plate (JIS standard SPCC series, etc.). The core bar 81 is mainly composed of a cylindrical portion 81a, a bent portion 81b, a disk portion 81c, and a flange portion 81d.

[0033] The cylindrical portion 81a 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 bent portion 81b is bent radially inward from the inner end of the cylindrical portion 81a, and then extends to the axial midpoint of the cylindrical portion 81a toward the outer side. Furthermore, the disk portion 81c extends radially inward from the outer end of the bent portion 81b to the vicinity of the outer periphery of the hub wheel 3 (more specifically, the shaft circumferential surface portion 31c described later).

[0034] Moreover, the flange portion 81d extends radially outward from the outer end of the cylindrical portion 81a. In addition, the radially outer end of the flange portion 81d 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 81d is provided with an outer edge portion 81e extending toward the inner side while having a predetermined gap with the outer peripheral surface 2e.

[0035] The core metal 81 is fitted, via the cylindrical portion 81a, into the outer opening 2b of the outer ring 2 (that is, the outer end of the annular space Q2 described above, which is the inner periphery of the outer ring 2).

[0036] The sealing body 82 is formed from 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 81 by vulcanization adhesion. In addition, the sealing body 82 is composed of a radial lip 82a, an inner axial lip 82b, and an outer axial lip 82c provided on the disc portion 81c of the core bar 81, a labyrinth lip 82d provided on the flange portion 81d of the core bar 81, and a dam portion 82e provided on the outer edge portion 81e of the core bar 81.

[0037] The radial lip 82a is provided at the radially inner end of the disk portion 81c, and is formed so as to extend toward the inner side and toward the radially inner side. The inner axial lip 82b is provided radially outward from the radial lip 82a and is formed so as to extend toward the outer side and radially outward. Furthermore, the outer axial lip 82c is provided radially outward with respect to the radial lip 82a and the inner axial lip 82b, and is formed so as to extend toward the outer side and radially outward.

[0038] The radial lip 82 a, the inner axial lip 82 b, and the outer axial lip 82 c are arranged coaxially with one another and are in sliding contact with the stepped portion 31 of the hub wheel 3.

[0039] Here, the step portion 31 refers to a portion provided at the base end portion of the wheel mounting flange 3b of the hub wheel 3, which protrudes towards the inner side. Specifically, the step portion 31 is composed of a first flat portion 31a consisting of a plane perpendicular to the rotation axis G, a second flat portion 31b also consisting of a plane perpendicular to the rotation axis G and continuing radially outward from the first flat portion 31a, an axial circumferential surface portion 31c extending coaxially with the rotation axis G and positioned radially inward from the first flat portion 31a, and an arc surface portion 31d smoothly connecting the first flat portion 31a and the axial circumferential surface portion 31c. Additionally, the outer circumferential surface portion 31e of the step portion 31 is inclined at a predetermined curvature, and smoothly connects from the outer edge of the second flat portion 31b to the bearing surface 31f of the hub bolt 3c.

[0040] The tip of the radial lip 82a contacts the axial surface portion 31c of the step portion 31 via an oil film of grease, which is a lubricant, and the tip of the inner axial lip 82b contacts the arc surface portion 31d of the step portion 31 via the oil film, and the tip of the outer axial lip 82c contacts the first flat portion 31a of the step portion 31 via the oil film. In this way, the outer seal member 8 is configured to be slidable relative to the hub wheel 3 by the radial lip 82a, the inner axial lip 82b, and the outer axial lip 82c contacting the step portion 31 via an oil film of grease.

[0041] The labyrinth lip 82d is located radially outward of the outer axial lip 82c, and is formed so as to extend axially toward the outer side, that is, toward the wheel mounting flange 3b of the hub wheel 3.

[0042] Specifically, the labyrinth slip 82d 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, an annular groove portion 3e recessed toward the outer side is provided on the inner side of the wheel mounting flange 3b of the hub wheel 3 (more specifically, the second flat surface portion 31b of the step portion 31) coaxially with the hub wheel 3 (i.e., coaxially with the rotation axis G).

[0043] The labyrinth slip 82d is disposed with its tip portion inserted in the annular groove portion 3e without contacting the annular groove portion 3e. That is, the labyrinth slip 82d forms a labyrinth seal together with the annular groove portion 3e, and is arranged so as to seal the gap between the outer end face of the outer ring 2 and the second flat portion 31b of the step portion 31 in the hub wheel 3, while containing the above-mentioned radial lip 82a, inner axial lip 82b, and outer axial lip 82c radially inwardly. As a result, for example, foreign matter (muddy water, dust, etc.) moving from the outside toward the outer axial lip 82c is received by the labyrinth slip 82d, guided circumferentially along the outer periphery of the labyrinth slip 82d, 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.

[0044] In this embodiment, a notch 3f is formed radially outward from the annular groove 3e of the hub wheel 3 and opens to the outside. The cutout portion 3f has, for example, a generally rectangular cross-section when viewed in the radial direction, and is composed of a groove portion with an open inner side surface, and is formed so as to extend directly downward from the annular groove portion 3e so as to cut out the lower end of the outer edge wall 3g that constitutes the annular groove portion 3e, as shown in FIG. 2. In other words, the inside of the annular groove portion 3e communicates with the outside of the hub wheel 3 via the cutout portion 3f.

[0045] And, for example, if a foreign object such as muddy water suddenly enters the annular groove portion 3e from the outside and, as a result, as shown in FIG. 1, the foreign object accumulates within the annular groove portion 3e in the space portion Q3 (the area shown by hatching in FIG. 1) located radially outward from the tip portion of the labyrinth slip 82d, the hub wheel 3 (more specifically, the outer side seal member 8) rotates relative to the outer ring 2, so that the foreign object is discharged to the outside by centrifugal force through the cutout portion 3f.

[0046] As described above, in the wheel bearing device 1 of this embodiment, the hub wheel 3 is provided with a notch portion 3f that connects the annular groove portion 3e to the outside of the hub wheel 3, so that even if a foreign object enters the annular groove portion 3e, the foreign object can be easily expelled to the outside of the hub wheel 3 via the notch portion 3f. Therefore, for example, it is possible to suppress the gradual accumulation of foreign matter in the annular groove portion 3e, which in turn can suppress the accelerated wear of the lip portion (in this embodiment, the labyrinth lip 82d) of the outer seal member 8, thereby maintaining stable sealing performance.

[0047] The dam portion 82e is provided in a generally rectangular shape in a 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 82e is provided on the core metal 81 so as to cover the radially outer end of the flange portion 81d as well as the outer edge portion 81e. As a result, for example, foreign matter such as muddy water flowing along the outer peripheral surface 2e of the outer ring 2 toward the labyrinth slip 82d is blocked by the dam portion 82e, thereby more effectively preventing foreign matter from entering the annular space Q2 in the wheel bearing device 1.

[0048] As described above, the wheel bearing device 1 in this embodiment is configured as a wheel bearing device of third generation structure in which the inner raceway 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 second generation structure in which a pair of inner rings are coaxially press-fitted onto the outer periphery of the hub wheel, and an inner raceway on which the ball row can roll is formed directly on the outer periphery of each of the inner rings.

[0049] [Configuration of wheel bearing device 101 (second embodiment)] Next, the configuration of a wheel bearing device 101 according to a second embodiment will be described with reference to FIGS. In Figure 1, the wheel bearing device 101 in the second embodiment has a configuration substantially equivalent to the wheel bearing device 1 in the first embodiment described above, but differs from the wheel bearing device 1 mainly in the configuration of the cutout portion 103f of the annular groove portion 103e provided in the hub wheel 103. Therefore, in the following description, differences from the above-described wheel support bearing device 1 will be mainly described, and a description of configurations equivalent to those of the wheel support bearing device 1 will be omitted.

[0050] In FIG. 3, an annular groove portion 103e recessed toward the outer side is provided on the inner side of the wheel mounting flange 103b of the hub wheel 103 coaxially with the hub wheel 103 (i.e., coaxially with the rotation axis G (see FIG. 1)). In this embodiment, the hub wheel 103 is provided with a notch 103f that is formed radially outward from the annular groove 103e and opens to the outside.

[0051] The configuration of the annular groove portion 103e is substantially the same as that of the annular groove portion 3e of the wheel bearing device 1 described above, and therefore a description thereof will be omitted.

[0052] The cutout portion 103f has, for example, a substantially rectangular cross-section when viewed in the radial direction, and consists of a groove portion with an open inner side surface, and is formed so as to extend directly downward from the annular groove portion 103e so as to cut out the lower end of the outer edge wall 103g that constitutes the annular groove portion 103e. In other words, the inside of the annular groove portion 103e communicates with the outside of the hub wheel 103 via the cutout portion 103f.

[0053] In addition, when viewed in the axial direction, the cutout portion 103f is formed in a trapezoidal shape whose cross-sectional shape gradually narrows toward the radially outward direction, and is set so that the cross-sectional area S2 of the end portion on the outer side of the hub wheel 103 is smaller than the cross-sectional area S1 of the end portion on the annular groove portion 103e side (S1>S2).

[0054] And, for example, if a foreign object such as muddy water suddenly enters the annular groove portion 103e from the outside, and as a result, as shown in FIG. 1, the foreign object accumulates in the aforementioned space portion Q3 within the annular groove portion 103e, the rotation of the hub wheel 103 relative to the outer ring 2 (more specifically, the outer side seal member 8) will cause the foreign object to be expelled to the outside by centrifugal force through the cutout portion 103f.

[0055] By providing such a cutout portion 103f formed in a trapezoidal shape when viewed in the axial direction, when the hub wheel 103 rotates relative to the outer ring 2 (outer side seal member 8), the gas remaining in the annular groove portion 103e is scraped outward in the radial direction.The flow rate of the gas is increased by the Venturi effect as it passes through the cutout portion 103f, and foreign matter accumulated inside the annular groove portion 103e can be more reliably discharged to the outside via the cutout portion 103f. Furthermore, since the cross-sectional shape of the cutout portion 103f tapers outward in the radial direction, it is possible to prevent foreign matter such as muddy water from entering the annular groove portion 103e from the outside through the cutout portion 103f.

[0056] [Configuration of wheel bearing device 201 (third embodiment)] Next, the configuration of a wheel bearing device 201 according to a third embodiment will be described with reference to FIGS. In Figure 1, a wheel bearing device 201 in the third embodiment has a configuration substantially equivalent to the wheel bearing device 1 in the first embodiment described above, but differs from the wheel bearing device 1 mainly in the configuration of the cutout portion 203f of the annular groove portion 203e provided in the hub wheel 203. Therefore, in the following description, differences from the above-described wheel support bearing device 1 will be mainly described, and a description of configurations equivalent to those of the wheel support bearing device 1 will be omitted.

[0057] In Figure 4(a), an annular groove portion 203e recessed toward the outer side is provided on the inner side of the wheel mounting flange 203b of the hub wheel 203, coaxially with the hub wheel 203 (i.e., coaxially with the rotation axis G (see Figure 1)). In this embodiment, a plurality of (five in this embodiment) notches 203f are provided which are formed radially outward from the annular groove portion 203e of the hub wheel 203 and open to the outside.

[0058] The configuration of the annular groove portion 203e is substantially the same as that of the annular groove portion 3e of the wheel bearing device 1 described above, and therefore a description thereof will be omitted.

[0059] Each notch portion 203f has a generally rectangular cross-section when viewed in the radial direction, and consists of a groove portion with an open inner side surface, and is formed to extend radially outward from the annular groove portion 203e so as to cut out the outer edge wall 203g that constitutes the annular groove portion 203e. In other words, the inside of the annular groove portion 203e communicates with the outside of the hub wheel 203 via each of the cutout portions 203f.

[0060] Furthermore, each notch portion 203f has a configuration equivalent to, for example, the notch portion 103f (see Figure 3) of the wheel bearing device 101 in the second embodiment described above, and is formed in a trapezoidal shape whose cross-sectional shape gradually narrows radially outward when viewed in the axial direction. The shape of each notch 203f is not limited to this embodiment, and may be formed, for example, in a rectangular shape extending radially outward when viewed in the axial direction, like the notch 3f (see Figure 2) of the wheel bearing device 1 in the first embodiment described above.

[0061] The multiple notch portions 203f·203f··· having this type of shape are provided at multiple locations (five locations in this embodiment) on the same circumference centered on the rotation axis G (see Figure 1) and are arranged at equal intervals along the annular groove portion 203e. In other words, the inside of the annular groove portion 203e communicates with the outside of the hub wheel 203 via the plurality of cutout portions 203f.

[0062] In this embodiment, the multiple notches 203f·203f··· are arranged at equal intervals along the annular groove portion 203e so that at least one notch 203f extends directly downward from the annular groove portion 203e. This configuration makes it easier for foreign matter to be discharged to the outside from the annular groove portion 203e through the cutout portion 203f due to the influence of gravity, etc.; however, the present invention is not limited to this.

[0063] That is, as shown in Figure 4(b), a number of cutout portions 203f·203f··· can be arranged at positions that are in the same phase as the positions of the multiple hub bolts 203c·203c··· provided on the wheel mounting flange 203b, and these multiple hub bolts 203c·203c··· can be configured to prevent as much as possible foreign matter from entering the annular groove portion 203e through the cutout portions 203f. The configuration of the hub bolt 203c is substantially the same as that of the hub bolt 3c of the wheel bearing device 1 described above, and therefore a description thereof will be omitted.

[0064] By configuring in this manner that multiple notches 203f·203f··· are equally spaced along the annular groove portion 203e, foreign matter that has accumulated inside the annular groove portion 203e can be more reliably discharged to the outside via these notches 203f·203f···.

[0065] In addition, as the hub wheel 203 rotates relative to the outer wheel 2 (more specifically, the outer seal member 8), the air in the annular groove portion 203e is expelled to the outside by centrifugal force, which results in the air pressure in the annular groove portion 203e becoming negative, which may lead to a concern that foreign matter such as muddy water may be easily sucked into the annular groove portion 203e. However, by providing multiple cutout portions 203f·203f··· as in this embodiment, the effects of such negative pressure can be reduced and foreign matter accumulated inside the annular groove portion 203e can be more stably expelled to the outside.

[0066] Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments, which are merely illustrative, and it goes without saying that the present invention can be embodied in various other forms without departing from the gist 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.

[0067] 1, 101, 201 Wheel bearing device 2 Outer ring (outer component) 2b Outer side opening 2c Outer raceway surface 3, 103, 203 Hub wheel 3a Small diameter stepped section 3b, 103b, 203b Wheel mounting flange 3d Inner raceway surface (inner component) 3e, 103e, 203e Circular groove 3f, 103f, 203f notch 4. Inner Circle 4a Inner raceway surface (inner component) 5 Ball row (rolling element) 8 Outer seal material 82d Labyrinth Slip Q2 Annular space

Claims

1. 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, an annular groove portion is provided coaxially with the hub wheel on an inner side surface of the wheel mounting flange of the hub wheel; The outer seal member is The wheel mounting flange is formed of an elastic material and extends in an axial direction toward the wheel mounting flange. a labyrinth slip having a tip end portion inserted into the annular groove in a non-contact state to form a labyrinth seal; the hub wheel has a notch portion that is formed radially outward from the annular groove portion and that opens to the outside, The cutout portion is In the axial view, The cross-sectional shape is formed into a trapezoidal shape that gradually decreases toward the radially outward direction. A wheel bearing device comprising:

2. The cutout portion is Located in multiple locations, are equally spaced along the annular groove portion, 2. A wheel bearing device according to claim 1, wherein the wheel bearing device is a bearing for a wheel.

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