JP7787645B2 - Wheel bearing device - Google Patents

Description

The present invention relates to a wheel bearing device.

Wheel bearing devices that support the rotation of wheels in the suspension of automobiles and other vehicles are known. Wheel bearing devices are equipped with a sealing device that closes the open end of the annular space formed by the outer and inner members to prevent the intrusion of foreign matter such as muddy water.

For example, the sealing device disclosed in Patent Document 1 comprises a core metal fitted onto the inner periphery of an outer ring (the outer member), a seal member integrally joined to the core metal, and a metal ring fitted onto a hub wheel (the inner member). A labyrinth seal is formed by the tapered portion of the metal ring that protrudes toward the core metal and the eaves portion of the seal member located on the outer diameter side of the tapered portion, preventing foreign matter such as muddy water from entering the sealing device. At the same time, by inclining the tapered portion of the metal ring in a direction that increases in diameter as it approaches the core metal, the sealing device is designed to easily expel foreign matter such as muddy water from the inside, even if it does enter the sealing device.

The sealing device disclosed in Patent Document 2 includes a slinger, a core, and a seal. The slinger has a slinger cylindrical portion that fits into the inner ring, a slinger standing plate portion that extends radially outward from the slinger cylindrical portion, and an outer cylindrical portion that is bent at an obtuse angle from the radial outer end of the slinger standing plate portion toward the outer side. The core has a core cylindrical portion that fits into the outer ring and a core standing plate portion that extends radially inward from the core cylindrical portion. The seal material has a seal cylindrical portion fixed to the core cylindrical portion and a seal standing plate portion fixed to the core standing plate portion.

The cylindrical seal portion and the outer cylindrical portion of the slinger form a labyrinth seal, and the cylindrical seal portion is formed with an annular return lip that extends toward the inner side, preventing foreign matter such as muddy water from entering the sealing device. Meanwhile, the outer cylindrical portion of the slinger is inclined in a direction that increases in diameter as it approaches the outer side, making it easier to expel foreign matter such as muddy water from the sealing device, even if it does enter the device.

Japanese Patent Application Laid-Open No. 2020-143703 Japanese Patent Application Laid-Open No. 2020-29871

However, if the sealing device is designed to easily expel foreign matter that has entered the sealing device to the outside, as in the sealing devices described in Patent Documents 1 and 2, even if a labyrinth seal is configured, there is a risk that grease that seeps out from inside the sealing device through the seal lip will leak out of the sealing device and splash onto brake components and other parts around the wheel bearing assembly.

The present invention was made in consideration of the above circumstances, and provides a wheel bearing device that can prevent grease that seeps out from the seal lip portion of the sealing device from scattering outside the sealing device.

That is, the wheel bearing device comprises an outer member having a double-row outer raceway surface on its inner periphery, a hub ring having a wheel mounting flange at one axial end for mounting a wheel and a small-diameter stepped portion extending axially on its outer periphery, and at least one inner ring press-fitted into the small-diameter stepped portion of the hub ring, an inner member having a double-row inner raceway surface facing 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 annular space formed by the outer member and the inner member in the axial direction. A wheel bearing assembly including a sealing device that closes the open end on one end side, the sealing device including a core metal that is fitted to the inner circumference of the outer member at one axial end side, a seal member that is integrally joined to the core metal, and a metal ring that is fitted to the base of the wheel mounting flange on the inner member, the seal member extending from the core metal toward the wheel mounting flange and having a contact lip that contacts the metal ring, and the metal ring having a groove that extends circumferentially on the outer diameter side of the contact lip.

The wheel bearing device also includes an outer member having a double-row outer raceway on its inner periphery, a hub ring having a wheel mounting flange at one axial end for mounting a wheel and a small-diameter stepped portion extending axially on its outer periphery, and at least one inner ring press-fitted into the small-diameter stepped portion of the hub ring, an inner member having a double-row inner raceway facing the double-row outer raceway, double-row rolling elements accommodated in a rollable manner between the raceway surfaces of the outer member and the inner member, and an annular space formed by the outer member and the inner member, the inner member being configured to have a single axially extending portion. A wheel bearing assembly including a sealing device that closes the open end of the outer member, the sealing device comprising a core metal fitted to the inner circumference of one axial end of the outer member, a seal member integrally joined to the core metal, and a metal ring fitted to the base of the wheel mounting flange of the inner member, the seal member having a contact lip that extends from the core metal towards the wheel mounting flange and makes contact with the metal ring, and the seal member having a groove extending circumferentially in a portion radially outward of the contact lip.

The wheel bearing device also includes an inner member having a double-row outer raceway surface on its inner circumference, a hub ring having a wheel mounting flange at one axial end for mounting a wheel and a small-diameter stepped portion extending axially on its outer circumference, and at least one inner ring press-fitted into the small-diameter stepped portion of the hub ring, the inner member having a double-row inner raceway surface facing 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 a sealing device that closes the open end at one axial end of the annular space formed by the outer member and the inner member, wherein the sealing device includes a core metal engaged with the inner circumference at one axial end of the outer member and a seal member integrally joined to the core metal, the seal member extending from the core metal towards the wheel mounting flange and having a contact lip in contact with the wheel mounting flange, and the wheel mounting flange having a groove extending circumferentially in a portion outer diameter side of the contact lip.

This invention prevents grease from scattering outside the sealing device.

1 is a side cross-sectional view showing a wheel bearing device. FIG. 4 is a side cross-sectional view showing an outer seal member. 4 is a view of the metal ring of the outer seal member as seen from the inner side in the axial direction. FIG. (a) is a diagram showing a state in which multiple arc-shaped grooves formed in a metal ring are arranged at the same radial position and intermittently along the circumferential direction, (b) is a diagram showing a state in which multiple arc-shaped grooves formed intermittently along the circumferential direction of the metal ring are arranged at different radial positions, and (c) is a diagram showing a state in which multiple arc-shaped grooves are arranged at different radial positions and overlap when viewed from the radial direction. FIG. 10 is a side cross-sectional view showing a first modified example of a groove of the outer seal member according to the first embodiment. FIG. 10 is a side cross-sectional view showing a second modified example of the groove of the outer seal member according to the first embodiment. FIG. 10 is a side cross-sectional view showing an outer seal member according to a second embodiment. FIG. 10 is a side cross-sectional view showing a modified example of a groove of the outer seal member according to the second embodiment. 10 is a side cross-sectional view showing an outer seal member and a wheel mounting flange of a wheel support bearing device according to another embodiment. FIG.

The following describes an embodiment of the present invention with reference to the accompanying drawings.

[Wheel bearing device]
A wheel bearing device 1 shown in FIG. 1 is one embodiment of a wheel bearing device according to the present invention, and is used to rotatably support a wheel in a suspension system of a vehicle such as an automobile.

The wheel bearing device 1 has a configuration known as the third generation, and includes an outer ring 2 as the outer member, a hub ring 3 and an inner ring 4 as the inner members, two rolling rows of inner balls 5 and outer balls 6, an inner seal member 9 and an outer seal member 10.

Here, the inner side refers to the vehicle body side of the wheel bearing device 1 when it is attached to the vehicle body, and the outer side refers to the wheel side of the wheel bearing device 1 when it is attached to the vehicle body. Furthermore, the axial direction refers to the direction along the rotational axis of the wheel bearing device 1, with one axial end side being the outer side and the other axial end side being the inner side.

An inner side opening 2a is formed at the inner side end of the outer ring 2, into which an inner side seal member 9 can be fitted. An outer side opening 2b is formed at the outer side end of the outer ring 2, into which an outer side seal member 10 can be fitted. The inner circumferential surface of the outer ring 2 is formed with an inner side outer raceway surface 2c and an outer side outer raceway surface 2d.

A vehicle body mounting flange 2e is integrally formed on the outer peripheral surface of the outer ring 2 for mounting the outer ring 2 to a vehicle body member. The vehicle body mounting flange 2e is provided with bolt holes 2g into which fastening members (here, bolts) are inserted to fasten the outer ring 2 to the vehicle body member.

The inner end of the outer peripheral surface 3j of the hub wheel 3 is formed with a small-diameter step 3a that is smaller in diameter than the outer end. A shoulder 3e is formed at the outer end of the small-diameter step 3a of the hub wheel 3. A wheel mounting flange 3b for mounting a wheel is integrally formed at the outer end of the hub wheel 3. Multiple bolt holes 3f are formed in the wheel mounting flange 3b. Hub bolts 3i for fastening the hub wheel 3 to a wheel or brake component are press-fitted into the bolt holes 3f.

The outer peripheral surface 3j of the hub ring 3 is provided with an outer inner raceway surface 3c that faces the outer outer raceway surface 2d of the outer ring 2. In other words, the hub ring 3 forms the inner raceway surface 3c on the outer side of the inner member. The outer seal member 10 is fitted into the outer opening end of the annular space formed by the outer ring 2 and hub ring 3, closing this outer opening end. The outer seal member 10 is an example of a sealing device. The hub ring 3 has an outer end face 3g at the end outer than the wheel mounting flange 3b.

An inner ring 4 is mounted on the small diameter step 3a of the hub ring 3. The inner ring 4 is fixed to the small diameter step 3a of the hub ring 3 by press fitting and crimping. The inner ring 4 applies preload to the inner ball row 5 and outer ball row 6, which are the rolling rows. The inner ring 4 has an inner end face 4b at its inner end and an outer end face 4c at its outer end. A crimped portion 3h is formed at the inner end of the hub ring 3, crimped to the inner end face 4b of the inner ring 4.

The outer peripheral surface of the inner ring 4 is provided with an inner-side inner raceway surface 4a that faces the inner-side outer raceway surface 2c of the outer ring 2. In other words, the inner ring 4 forms the inner raceway surface 4a on the inner side of the inner member.

The inner ball row 5 and outer ball row 6, which are rolling rows, are composed of a plurality of balls 7, which serve as rolling elements, held in a cage 8. The inner ball row 5 is rollably sandwiched between the inner raceway surface 4a of the inner ring 4 and the inner outer raceway surface 2c of the outer ring 2. The outer ball row 6 is rollably sandwiched between the inner raceway surface 3c of the hub ring 3 and the outer outer raceway surface 2d of the outer ring 2. In other words, the inner ball row 5 and outer ball row 6 are rollably housed between the raceway surfaces of the outer member and the inner member.

In the wheel bearing device 1, a double-row angular contact ball bearing is formed by the outer ring 2, hub ring 3, inner ring 4, inner ball row 5, and outer ball row 6. Note that the wheel bearing device 1 may also be formed as a double-row tapered roller bearing instead of a double-row angular contact ball bearing.

[First embodiment of outer seal member]
As shown in Figure 2, the outer seal member 10 of the first embodiment comprises a core 11 fitted to the inner circumference of the outer side of the outer ring 2, a seal member 12 integrally joined to the core 11, and a metal ring 13 fitted to the base 3d of the wheel mounting flange 3b of the hub wheel 3.

The core metal 11 is made of, for example, steel plate and has a cylindrical fitting portion 11a that fits onto the inner circumference of the outer opening 2b of the outer ring 2, an inner portion 11b that extends from the inner end of the fitting portion 11a toward the inner diameter side, an outer portion 11c that extends from the outer end of the fitting portion 11a toward the outer diameter side, and an outer edge portion 11d that extends from the outer diameter end of the outer portion 11c toward the inner side. The inner portion 11b is bent from the inner end of the fitting portion 11a and extends toward the outer and inner diameter sides, and then extends toward the inner diameter side. The outer edge portion 11d extends toward the inner side with a predetermined gap between it and the outer peripheral surface 2h of the outer ring 2.

The sealing member 12 is formed from an elastic material such as synthetic rubber and is bonded to the core metal 11 by vulcanization bonding. The sealing member 12 has a base portion 12a, a radial lip 12b, a first side lip 12c, a second side lip 12d, a third side lip 12e, and a dam portion 12f. The base portion 12a is bonded from the inner portion 11b of the core metal 11, via the fitting portion 11a and outer portion 11c, to the outer edge portion 11d.

The radial lip 12b is located at the inner diameter end of the seal member 12 and extends radially inward and toward the inner side from the inner portion 11b of the core metal 11. The radial lip 12b is in sliding contact with the metal ring 13 via an oil film of grease G.

The first side lip 12c extends radially outward from the inner portion 11b of the core 11 toward the wheel mounting flange 3b and radially outward, radially outward of the radial lip 12b. The first side lip 12c is in sliding contact with the metal ring 13 via an oil film of grease G. The first side lip 12c is an example of a contact lip that comes into contact with the metal ring.

In the outer seal member 10, grease G is filled in the space surrounded by the radial lip 12b, first side lip 12c, and metal ring 13.

The second side lip 12d extends radially outward from the inner portion 11b of the core metal 11 toward the wheel mounting flange 3b and radially outward, radially outward from the first side lip 12c. The second side lip 12d also faces the metal ring 13 in the axial direction with a gap between them.

The third side lip 12e extends radially outward from the outer portion 11c of the core 11 toward the wheel mounting flange 3b, further radially outward than the second side lip 12d. The third side lip 12e faces the inner side surface 3k of the wheel mounting flange 3b in the axial direction, with a gap between them. The third side lip 12e is an example of a labyrinth lip that faces the wheel mounting flange with a gap between them.

The dam portion 12f covers the outer edge portion 11d of the core metal 11, protrudes radially outward beyond the outer peripheral surface 2h of the outer ring 2, and is in contact with the outer peripheral surface 2h of the outer ring 2.

The metal ring 13 is made of, for example, a steel plate and has a cylindrical portion 13a, a disk portion 13b, a connecting portion 13c, and a protruding portion 13d.

The cylindrical portion 13a is formed in a cylindrical shape and is fitted onto the outer peripheral surface 3j of the hub wheel 3, on the inner side of the wheel mounting flange 3b. The cylindrical portion 13a faces the radial lip 12e in the radial direction, and the cylindrical portion 13a and the radial lip 12e are in sliding contact with each other via an oil film of grease G.

The disc portion 13b is formed in a disc shape and faces the inner side surface 3k of the wheel mounting flange 3b in the axial direction with a gap. The disc portion 13b faces the second side lip 12d in the axial direction with a gap.

The connecting portion 13c connects the cylindrical portion 13a and the disc portion 13b. The connecting portion 13c faces the first side lip 12c in the axial direction, and the connecting portion 13c and the first side lip 12c are in sliding contact with each other via an oil film of grease G.

The protrusion 13d protrudes inward and radially outward from the radially outer end of the disc portion 13b. The protrusion 13d is located radially between the second side lip 12d and the third side lip 12e. The protrusion 13d faces the base 12a of the seal member 12 with a gap between them, between the second side lip 12d and the third side lip 12e in the radial direction. The protrusion 13d is located radially outer than the first side lip 12c.

The second and third side lips 12d and 12e of the seal member 12 overlap the protrusion 13d of the metal ring 13 when viewed radially, and a labyrinth seal is formed by the second and third side lips 12d and 12e and the protrusion 13d. The labyrinth seal formed by the second and third side lips 12d and 12e and the protrusion 13d prevents foreign matter such as muddy water from entering the interior of the outer seal member 10.

Protrusion 13d has an outer peripheral surface 131, a tip surface 132, and an inner peripheral surface 133. An elastic member 14 is integrally bonded to outer peripheral surface 131 and tip surface 132 of protrusion 13d. Elastic member 14 is formed, for example, from synthetic rubber, and has outer peripheral surface portion 14a bonded to outer peripheral surface 131 and tip portion 14b bonded to tip surface 132. Outer peripheral surface portion 14a contacts the inner side surface 3k of wheel mounting flange 3b, sealing the gap between wheel mounting flange 3b and disc portion 13b of metal ring 13.

[groove]
As shown in Figures 2 and 3, the inner circumferential surface 133 of the protrusion 13d has a groove 133a. The groove 133a extends along the circumferential direction of the inner circumferential surface 133. In this embodiment, the groove 133a is formed in an endless circular shape extending around the entire circumferential direction. The groove 133a can be formed by pressing, for example, simultaneously with forming the metal ring 13 by pressing. In this way, the groove 133a can be formed simultaneously with forming the metal ring 13 by pressing, so there is no need to provide a separate process or part for forming the groove 133a, and it can be formed without increasing costs.

In this embodiment, the cross-sectional shape of the groove 133a is formed to be approximately V-shaped. However, this is not limited to this, and the groove 133a can be formed to have any cross-sectional shape. For example, the cross-sectional shape of the groove 133a can be formed to be U-shaped or arc-shaped, etc.

The depth of the groove 133a can be formed to any desired depth. However, from the standpoint of the strength and shape retention of the metal ring 13, it is preferable to set the maximum depth to approximately half the thickness dimension of the protrusion 13d.

In addition, in this embodiment, two circular grooves 133a are arranged side by side in the radial direction on the inner circumferential surface 133 of the protrusion 13d. However, this is not limited to this, and it is also possible to form one groove 133a on the inner circumferential surface 133, or three or more grooves 133a.

As shown in Figure 4(a), the groove 133a can also be formed in an arc shape that extends over a portion of the circumference. In this case, multiple arc-shaped grooves 133a can be arranged intermittently along the circumference. In the case of Figure 4(a), the multiple grooves 133a arranged intermittently along the circumference are arranged at the same radial position.

Furthermore, as shown in Figure 4(b), when multiple arc-shaped grooves 133a are arranged intermittently along the circumferential direction, the multiple grooves 133a can be arranged at different positions in the radial direction. Furthermore, as shown in Figure 4(c), when multiple arc-shaped grooves 133a are arranged at different positions in the radial direction, the grooves 133a that are adjacent in the circumferential direction can be arranged so that they overlap when viewed from the radial direction.

Furthermore, when multiple arc-shaped grooves 133a are formed in the radial direction, it is also possible to form the grooves 133a in a single continuous spiral shape.

In the outer seal member 10, grease G is filled in the space surrounded by the radial lip 12b, first side lip 12c, and metal ring 13, but this grease G may seep out from between the first side lip 12c and the metal ring 13 toward the outer diameter side. The grease G that seeps out from between the first side lip 12c and the metal ring 13 may run along the inner side surface of the disc portion 13b of the metal ring 13 and the inner circumferential surface 133 of the protrusion 13d, and then leak out of the outer seal member 10.

However, the outer seal member 10 has a groove 133a on the inner circumferential surface 133 of the protrusion 13d, which is located radially outward of the first side lip 12c. As a result, grease G that seeps out from between the first side lip 12c and the metal ring 13 is trapped in the groove 133a as it moves radially outward along the inner circumferential surface 133.

This prevents grease G from moving radially outward from the groove 133a and scattering outside the outer seal member 10. Since the amount of grease G that seeps out from between the first side lip 12c and the metal ring 13 is usually small, it can be adequately captured by the groove 133a. The number of grooves 133a formed on the inner circumferential surface 133 of the protrusion 13d can be set appropriately depending on the amount of grease G that seeps out from between the first side lip 12c and the metal ring 13.

Furthermore, by forming the grooves 133a around the entire circumferential circumference of the outer seal member 10, the grease G can be stored in the grooves 133a at all phases in the circumferential direction, making it possible to more effectively prevent the grease G from scattering outside the outer seal member 10.

In addition, the protruding portion 13d of the metal ring 13 protrudes from the disc portion 13b toward the inner side, and the inner peripheral surface 133 faces the inner diameter side. Therefore, when the hub wheel 3 rotates, the grease G stored in the groove 133a is subjected to centrifugal force in the depth direction of the groove 133a. This prevents the grease G stored in the groove 133a from overflowing from the groove 133a due to centrifugal force while the hub wheel 3 is rotating, and further prevents the grease G from scattering outside the outer seal member 10.

[First Modification of the Groove of the Outer Seal Member According to the First Embodiment]
The groove for storing the grease G can also be formed in the disk portion 13b of the metal ring 13. In the outer seal member 10 shown in Figure 5, instead of forming the groove 133a in the protruding portion 13d of the metal ring 13, a groove 134a is formed in the inner side surface 134 of the disk portion 13b.

The grooves 134a can be formed, for example, by pressing when the metal ring 13 is formed by pressing. In this way, the grooves 134a can be formed simultaneously when the metal ring 13 is pressed, eliminating the need for a separate process or component for forming the grooves 134a and allowing for formation without increasing costs. In this embodiment, two circular grooves 134a are arranged side by side in the radial direction on the inner side surface 134 of the disc portion 13b.

Even when grooves 134a are formed on the inner side surface 134 of the disc portion 13b in this way, grease G that seeps out from between the first side lip 12c and the metal ring 13 is stored in the grooves 134a as it moves radially outward along the inner side surface 134. This prevents grease G from moving radially outward beyond the grooves 134a and scattering outside the outer seal member 10.

As with groove 133a, groove 134a can be formed on the inner side surface 134 of disc portion 13b, either singly or in three or more in number. Also, as with groove 133a, groove 134a can be formed in an arc shape extending over a portion of the circumference. Furthermore, as with groove 133a, groove 134a can be formed in any shape and depth.

[Second Modification of the Groove of the Outer Seal Member According to the First Embodiment]
The groove for storing the grease G can also be formed in the tip portion 14b of the elastic member 14 of the metal ring 13. In the outer seal member 10 shown in Fig. 6, instead of forming the groove 133a in the protruding portion 13d of the metal ring 13, a groove 141a is formed in the inner circumferential surface 141 at the tip portion 14b of the elastic member 14.

The groove 141a can be formed, for example, at the same time as molding the elastic member 14. In this way, the groove 141a can be formed at the same time as molding the elastic member 14, so there is no need to provide a separate process or component for forming the groove 141a, and it can be formed without increasing costs. In this embodiment, one circular groove 141a is formed radially on the inner circumferential surface 141 of the tip portion 14b.

Even when a groove 141a is formed on the inner circumferential surface 141 of the tip portion 14b, grease G that seeps out from between the first side lip 12c and the metal ring 13 is stored in the groove 141a as it moves outward along the inner circumferential surface 141. This prevents grease G from moving outward beyond the groove 141a and scattering outside the outer seal member 10.

It is also possible to form two or more grooves 141a on the inner circumferential surface 141 of the tip portion 14b. Furthermore, similar to the groove 133a, the groove 141a can also be formed in an arc shape that extends over part of the circumference. Furthermore, the groove 141a can be formed in any shape and to any depth.

In the outer seal member 10, grooves for storing grease G, such as grooves 133a, 134a, and 141a, can be formed at any location on the metal ring 13 or elastic member 14 that is radially outward of the first side lip 12c. However, from the perspective of storing grease G, it is preferable to form them in a location where a large amount of grease G that seeps out from between the first side lip 12c and the metal ring 13 passes through. Groove 133a, groove 134a, and groove 141a can also be formed together in any combination.

[Second embodiment of outer seal member]
7, the outer seal member 10A according to the second embodiment differs from the outer seal member 10 according to the first embodiment in that the groove for storing grease G is formed in the seal member 12A instead of in the metal ring. The rest of the configuration of the outer seal member 10A is the same as that of the outer seal member 10, and therefore a description thereof will be omitted.

The metal ring 13A of the outer seal member 10A does not have a groove for storing grease G. The seal member 12A of the outer seal member 10A has a groove for storing grease G.

In the seal member 12A, a groove 121a is formed in the inner circumferential surface 121 of the third side lip 12e, which is located radially outward of the first side lip 12c. The groove 121a can be formed, for example, at the same time as the seal member 12A is molded. Because the groove 121a can be formed at the same time as the seal member 12A is molded, there is no need for a separate process or component for forming the groove 121a, and it can be formed without increasing costs. In this embodiment, two circular grooves 121a are arranged side by side in the axial direction on the inner circumferential surface 121 of the third side lip 12e.

In the outer seal member 10, grease G seeping out from between the first side lip 12c and the metal ring 13 may run along the inner circumferential surface 133 of the protrusion 13d on the metal ring 13 and then splash onto the inner circumferential surface 121 of the third side lip 12e, which is located on the outer circumferential side of the protrusion 13d.

However, by forming a groove 121a on the inner circumferential surface 121 of the third side lip 12e, grease G scattered onto the inner circumferential surface 121 is collected in the groove 121a as it moves from the inner side to the outer side. This prevents grease G from moving further outward than the groove 121a and scattering outside the outer seal member 10.

In particular, because the third side lip 12e extends from the base 12a toward the outer side and the inner circumferential surface 121 faces the inner diameter side, when the hub wheel 3 rotates, the grease G stored in the groove 121a is subjected to centrifugal force in the depth direction of the groove 121a. This prevents the grease G stored in the groove 121a from overflowing from the groove 121a due to centrifugal force while the hub wheel 3 is rotating, and prevents the grease G from scattering outside the outer seal member 10.

As with groove 133a, groove 121a can be formed on the inner circumferential surface 121 of the third side lip 12e, either singly or in numbers of three or more. As with groove 133a, groove 121a can also be formed in an arc shape extending over a portion of the circumference. Furthermore, groove 121a can be formed in any shape and depth.

[Modification of the groove of the outer seal member according to the second embodiment]
The groove for storing the grease G can also be formed in the base 12a of the seal member 12A. In the seal member 12A shown in Fig. 8, a groove 122a is formed in the outer side surface 122 of the base 12a located between the second side lip 12d and the third side lip 12e in the radial direction.

The grooves 122a can be formed, for example, at the same time as the sealing member 12A is molded. In this way, the grooves 122a can be formed at the same time as the sealing member 12A is molded, eliminating the need for a separate process or component for forming the grooves 122a and allowing them to be formed without increasing costs. In this embodiment, two circular grooves 122a are arranged side by side in the radial direction on the outer side surface 122 of the base 12a.

In the outer seal member 10A, grease G seeps outward from between the first side lip 12c and the metal ring 13, runs along the inner circumferential surface 133 of the protrusion 13d of the metal ring 13, and may then splash onto the outer side surface 122 of the base 12a of the seal member 12A.

However, by forming a groove 122a on the outer side surface 122 of the base 12a, the grease G that has scattered onto the outer side surface 122 is collected in the groove 122a as it moves from the inner diameter side to the outer diameter side. This prevents the grease G from moving further outward than the groove 122a and scattering outside the outer seal member 10A.

As with groove 133a, groove 122a can be formed on the outer side surface 122 of base 12a, either singly or in three or more in number. Also, as with groove 133a, groove 122a can be formed in an arc shape that extends over a portion of the circumference. Furthermore, groove 122a can be formed in any shape and depth.

In the outer seal member 10A, grooves for storing grease G, such as grooves 121a and 122a, can be formed at any location on the outer diameter side of the first side lip 12c of the seal member 12A. For example, grooves can also be formed on the inner diameter surface of the second side lip 12d. However, from the perspective of storing grease G, it is preferable to form the grooves in locations where a large amount of grease G that seeps out from between the first side lip 12c and the metal ring 13 passes through.

It is also possible to form both groove 121a and groove 122a in the outer seal member 10A. Furthermore, grooves 121a and 122a in the outer seal member 10A and grooves 133a, 134a, and 141a in the outer seal member 10A can be formed together in any combination.

[Another embodiment of the wheel bearing device]
9, a wheel bearing device 1A according to another embodiment differs from the wheel bearing device 1 in that a groove for storing grease G is formed in the wheel mounting flange 3b of the hub ring 3A, and an outer seal member 110 is provided instead of the outer seal member 10 or the outer seal member 10A. The rest of the configuration of the wheel bearing device 1A is the same as that of the wheel bearing device 1, so a description thereof will be omitted.

The outer seal member 110 comprises a core metal 111 that is fitted to the inner circumference of the outer ring 2 on the outer side, and a seal member 112 that is integrally joined to the core metal 111.

The core metal 111 is made of, for example, a steel plate and has a cylindrical fitting portion 111a that fits onto the inner circumference of the outer opening 2b of the outer ring 2, an inner portion 111b that extends from the inner end of the fitting portion 111a toward the inner diameter side, an outer portion 111c that extends from the outer end of the fitting portion 111a toward the outer diameter side, and an outer edge portion 111d that extends from the outer diameter end of the outer portion 111c toward the inner side. The inner portion 111b is bent from the inner end of the fitting portion 111a and extends toward the outer and inner diameter sides, and then extends toward the inner diameter side. The outer edge portion 111d extends toward the inner side with a predetermined gap between it and the outer peripheral surface 2h of the outer ring 2.

The sealing member 112 is formed from an elastic material such as synthetic rubber, and is bonded to the core metal 111 by vulcanization adhesion. The sealing member 112 has a base portion 112a, a radial lip 112b, a first side lip 112c, a second side lip 112d, and a dam portion 112e. The base portion 112a is bonded from the inner portion 111b of the core metal 111, via the fitting portion 111a and the outer portion 111c, to the outer edge portion 111d.

The radial lip 112b is located at the inner diameter end of the seal member 112 and extends radially inward and toward the inner side from the inner portion 111b of the core metal 111. The radial lip 112b is in sliding contact with the outer peripheral surface 3j of the hub wheel 3A via an oil film of grease G.

The first side lip 112c extends radially outward from the inner portion 111b of the core 111 toward the wheel mounting flange 3b and radially outward, radially outward of the radial lip 112b. The first side lip 112c is in sliding contact with the base portion 3d of the wheel mounting flange 3b via an oil film of grease G. The first side lip 112c is an example of a contact lip that comes into contact with the wheel mounting flange.

The second side lip 112d extends radially outward from the inner portion 111b of the core 111 toward the wheel mounting flange 3b and radially outward, radially outward from the first side lip 112c. The second side lip 112d is in sliding contact with the base portion 3d of the wheel mounting flange 3b via an oil film of grease G. The second side lip 112d is an example of a contact lip that comes into contact with the wheel mounting flange.

In the outer seal member 110, grease G is filled in the space surrounded by the radial lip 112b, first side lip 112c, and hub wheel 3, and in the space surrounded by the first side lip 112c, second side lip 112d, and hub wheel 3.

The dam portion 112e covers the outer edge portion 111d of the core metal 111, protrudes radially outward beyond the outer peripheral surface 2h of the outer ring 2, and is in contact with the outer peripheral surface 2h of the outer ring 2.

The wheel mounting flange 3b has a groove 31 extending circumferentially on the inner side surface 3k, on the outer diameter side of the second side lip 112d. The groove 31 can be formed, for example, by turning or grinding the inner side surface 3k of the wheel mounting flange 3b.

In this embodiment, the groove 31 is formed in an endless circle extending around the entire circumference. However, the groove 31 can also be formed in an arc shape that is formed on part of the circumference. In this case, multiple arc-shaped grooves 31 can be arranged intermittently along the circumference. Furthermore, multiple arc-shaped grooves 31 can be arranged at the same radial position, or at different radial positions.

In this embodiment, the cross-sectional shape of the groove 31 is formed as an arc, but this is not limited to this and the groove can be formed into any cross-sectional shape. For example, the cross-sectional shape of the groove 31 can be formed into a V-shape or a U-shape. The depth of the groove 31 can be formed to any depth.

In addition, in this embodiment, two circular grooves 31 are arranged side by side in the radial direction on the inner side surface 3k of the wheel mounting flange 3b. However, this is not limited to this, and it is also possible to form one groove 31 on the inner side surface 3k, or three or more grooves 31. When forming multiple grooves 31 in the radial direction, it is also possible to form the groove 31 in a single continuous spiral shape.

In the outer seal member 110, grease G is filled in the space surrounded by the first side lip 112c, the second side lip 112d, and the hub wheel 3. However, this grease G may seep out from between the second side lip 112d and the inner side surface 3k toward the outer diameter. After sloshing along the inner side surface 3k toward the outer diameter, the grease G that seeps out from between the second side lip 112d and the inner side surface 3k may be splashed onto brake components and other components around the wheel bearing device 1A.

However, the wheel mounting flange 3b of the hub wheel 3 has a groove 31 on the inner side surface 3k at a portion located radially outward of the second side lip 112d. As a result, grease G seeping out from between the second side lip 112d and the inner side surface 3k is trapped in the groove 31 as it moves along the inner side surface 3k toward the radially outward side.

This prevents grease G from moving radially outward from the groove 31 and scattering outside the outer seal member 110, and further prevents it from scattering around the wheel bearing device 1A. Since the amount of grease G that seeps out from between the second side lip 112d and the inner side surface 3k is usually small, the groove 31 can adequately capture it. The number of grooves 133a formed on the inner side surface 3k of the wheel mounting flange 3b can be set appropriately depending on the amount of grease G that seeps out from between the second side lip 112d and the inner side surface 3k.

Furthermore, since the grooves 31 are formed around the entire circumference of the hub wheel 3, the grease G can be stored in the grooves 31 at all phases in the circumferential direction, making it possible to more effectively prevent the grease G from scattering outside the outer seal member 110 and even around the wheel bearing device 1A.

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 illustrative, and it goes without saying that the present invention can be embodied in a variety of 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, as well as all modifications within the scope of the claims.

REFERENCE SIGNS LIST 1, 1A Wheel bearing device 2 Outer ring 2b Outer-side opening 2c (Inner-side) outer raceway surface 2d (Outer-side) outer raceway surface 3, 3A Hub ring 3b Wheel mounting flange 3c Inner raceway surface 3d Base 4 Inner ring 4a Inner raceway surface 5 Inner-side ball row 6 Outer-side ball row 10, 10A, 110 Outer-side seal member 11, 111 Core metal 12, 12A, 112 Seal member 12c First side lip 12e Third side lip 13, 13A Metal ring 14 Elastic member 13d Projection 31 Groove 112d Second side lip 121a, 122a Groove 133a, 134a, 141a Groove G Grease

Claims (3)

an outer member having a double-row outer raceway surface on its inner periphery;
an inner member including a hub ring having a wheel mounting flange at one axial end for mounting a wheel and having a small diameter stepped portion extending in the axial direction on its outer periphery, and at least one inner ring press-fitted into the small diameter stepped portion of the hub ring, the inner member having double row inner raceway surfaces facing the double row outer raceway surfaces;
double-row rolling elements rollably accommodated between the raceway surfaces of the outer member and the inner member;
a sealing device that closes an open end on one axial end side of an annular space formed by the outer member and the inner member,
The sealing device is
a core metal fitted to an inner periphery of one axial end of the outer member;
a seal member integrally joined to the core metal;
a metal ring fitted to a base of the wheel mounting flange of the inner member,
the seal member extends from the core metal toward the wheel mounting flange and has a contact lip that comes into contact with the metal ring;
the metal ring has a protruding portion that protrudes toward the core metal and forms a labyrinth seal between itself and the second side lip and the third side lip, the protruding portion being located radially between a second side lip of the seal member that faces the metal ring with a gap at a position radially outer than the contact lip and a third side lip of the seal member that faces the wheel mounting flange with a gap at a position radially outer than the second side lip; and a groove that is formed in the protruding portion and extends circumferentially at a portion radially outer than the contact lip.
The groove is open toward the inner diameter side. an outer member having a double-row outer raceway surface on its inner periphery;
an inner member including a hub ring having a wheel mounting flange at one axial end for mounting a wheel and having a small diameter stepped portion extending in the axial direction on its outer periphery, and at least one inner ring press-fitted into the small diameter stepped portion of the hub ring, the inner member having double row inner raceway surfaces facing the double row outer raceway surfaces;
double-row rolling elements rollably accommodated between the raceway surfaces of the outer member and the inner member;
a sealing device that closes an open end on one axial end side of an annular space formed by the outer member and the inner member,
The sealing device is
a core metal fitted to an inner periphery of one axial end of the outer member;
a seal member integrally joined to the core metal;
a metal ring fitted to a base of the wheel mounting flange of the inner member,
the seal member extends from the core metal toward the wheel mounting flange and has a contact lip that comes into contact with the metal ring;
The metal ring has a protruding portion that protrudes toward the core metal side on the outer diameter side of the contact lip so as to face the seal member with a gap in the axial direction , an elastic member that is joined to a tip of the protruding portion, and a groove that is formed in the elastic member and extends in a circumferential direction in a portion that is outer diameter side of the contact lip,
The groove is open toward the inner diameter side. 3. The wheel bearing device according to claim 1, wherein the groove is formed over the entire circumference in the circumferential direction.