JP7723484B2 - 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 includes a core metal fitted to the inner periphery of the outer ring, which is the outer member; a seal member integrally joined to the core metal and having multiple seal lips; and a metal ring fitted to the base of the wheel mounting flange formed on the hub wheel, which is the inner member, and having a disc portion that is in close contact with the side of the wheel mounting flange and a bent portion that bends from the outer diameter portion of the disc portion toward the side that is axially away from the wheel mounting flange.

The multiple seal lips of the seal member and the bent portions of the metal ring located radially between the multiple seal lips form a complex labyrinth seal, preventing muddy water from entering the sealing device.

JP 2017-48809 A

However, in a configuration with a complex labyrinth seal, such as the sealing device described in Patent Document 1, once muddy water has entered the labyrinth seal, it is difficult for it to be drained to the outside. If muddy water remains inside the labyrinth seal for a period of time, the muddy water dries and the resulting mud accelerates wear on the seal lip, ultimately resulting in a decrease in muddy water resistance.

The present invention was made in consideration of the above circumstances, and aims to provide a wheel bearing device that can easily drain muddy water that has entered the labyrinth seal, even when the sealing device has a labyrinth seal.

That is, the wheel bearing device comprises 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 a sealing device that closes the open end on one axial end of the annular space formed by the outer member and the inner member, the sealing device comprising a core metal fitted to the inner periphery on 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 extending from the core metal to the wheel mounting flange of the inner member a first seal lip extending from the core toward the wheel mounting flange and opposing the wheel mounting flange with a gap; and a second seal lip extending from the core toward the wheel mounting flange radially inward of the first seal lip and opposing the metal ring with a gap. The metal ring contacts the base of the wheel mounting flange and has a disc portion opposing the second seal lip, and a protruding portion protruding from the radially outer end of the disc portion toward the core and opposing the seal member with a gap between the first seal lip and the second seal lip in the radial direction. The first seal lip, the second seal lip, and the protruding portion overlap when viewed radially. The seal member has a drain portion in a predetermined circumferential region where at least one of the first seal lip and the second seal lip is missing.

This invention makes it easier for muddy water that has entered the sealing device to be discharged to the outside of the sealing device through the drain section.

1 is a side cross-sectional view showing a wheel bearing device. FIG. 10 is a side cross-sectional view showing an outer seal member in a region where no drain portion is formed. 4 is a view showing an outer seal member as viewed from the outer side in the axial direction; FIG. FIG. 4 is a side cross-sectional view showing an outer seal member in a region where a drain portion is formed. 1 is a side cross-sectional view showing a drain portion in which only the first side lip is not formed and the second side lip is formed. 1 is a side cross-sectional view showing a drain portion in which only the second side lip is not formed and the first side lip is formed. 10 is a view of a seal member configured so that the circumferential length of a drain portion decreases from the radially inner side to the radially outer side, as viewed from the outer side in the axial direction. 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 lower side of the wheel bearing device 1 when it is attached to the vehicle body is referred to as the road side, and the upper side is referred to as the opposite road side. Furthermore, the axial direction refers to the direction along the rotation 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.

[Outer seal material]
As shown in Figure 2, the outer seal member 10 has a core 11 that is fitted to the inner circumference of the outer side of the outer ring 2, a seal member 12 that is integrally joined to the core 11, and a metal ring 13 that is fitted onto the base 3d of the wheel mounting flange 3b of the hub wheel 3.

The core metal 11 is made of, for example, a 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, and an outer portion 11c that extends from the outer end of the fitting portion 11a toward the outer diameter side. After extending toward the outer diameter side from the fitting portion 11a toward the outer diameter side, the outer portion 11c is bent toward the inner side along the outer peripheral surface 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 12a, a first side lip 12b, a second side lip 12c, a third side lip 12d, and a radial lip 12e. The base 12a is bonded to the core metal 11 from the inner portion 11b through the mating portion 11a to the outer portion 11c.

The first side lip 12b extends from the outer portion 11c of the core 11 toward the wheel mounting flange 3b, which is the outer side, and faces the inner side surface of the base 3d of the wheel mounting flange 3b with a gap in the axial direction. The tip surface of the first side lip 12b facing the base 3d of the wheel mounting flange 3b is formed into a flat surface facing in the axial direction. The first side lip 12b is an example of a first seal lip.

The second side lip 12c extends from the core 11 radially inward of the first side lip 12b toward the outer wheel mounting flange 3b. Specifically, the second side lip 12c extends from the inner portion 11b of the core 11 toward the wheel mounting flange 3b and radially outward. The second side lip 12c also faces the metal ring 13 with a gap between them. The second side lip 12c is an example of a second seal lip.

The third side lip 12d extends from the core 11 radially inward of the second side lip 12c toward the outer wheel mounting flange 3b. Specifically, the third side lip 12d extends from the inner portion 11b of the core 11 toward the wheel mounting flange 3b and radially outward. The third side lip 12d also makes sliding contact with the metal ring 13.

The radial lip 12e extends radially inward from the core 11, radially inward from the third side lip 12d. Specifically, the radial lip 12e extends radially inward and toward the inner side from the inner portion 11b of the core 11. The radial lip 12e also makes sliding contact with the metal ring 13.

The metal ring 13 is made of, for example, a steel plate and has a disk portion 13a, a cylindrical portion 13b, a connecting portion 13c, and a protruding portion 13d. The disk portion 13a is formed in a disk shape and contacts the inner side surface of the base portion 3d of the wheel mounting flange 3b. The disk portion 13a faces the second side lip 12c in the axial direction with a gap between them.

The cylindrical portion 13b is cylindrically formed and 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 13b faces the radial lip 12e in the radial direction, and the cylindrical portion 13b and the radial lip 12e are in sliding contact. The connecting portion 13c connects the disc portion 13a and the cylindrical portion 13b. The connecting portion 13c faces the third side lip 12d in the axial direction, and the connecting portion 13c and the third side lip 12d are in sliding contact.

The protrusion 13d protrudes from the radially outer end of the disc portion 13a toward the inner core metal 11 side. The protrusion 13d is located between the first side lip 12b and the second side lip 12c in the radial direction. The protrusion 13d faces the base 12a of the seal member 12 with a gap between them, between the first side lip 12b and the second side lip 12c in the radial direction. An elastic member 14 is integrally bonded to the outer peripheral surface of the protrusion 13d. The elastic member 14 is made of, for example, synthetic rubber.

In the outer seal member 10 configured in this manner, the first side lip 12b and second side lip 12c of the seal member 12 overlap the protrusion 13d of the metal ring 13 when viewed radially, and the first side lip 12b, second side lip 12c, and protrusion 13d form a labyrinth seal.

The first side lip 12b, second side lip 12c, and protrusion 13d are located on the outer periphery of the outer seal member 10, and the first side lip 12b, second side lip 12c, and protrusion 13d form a labyrinth seal, preventing muddy water from entering the interior of the outer seal member 10.

In this way, when a labyrinth seal is formed in the outer seal member 10 to prevent muddy water from entering the interior, once muddy water has entered the labyrinth seal, it tends to be difficult to drain. Therefore, in the outer seal member 10, a drain portion 12A is formed in the seal member 12 so that muddy water can be easily drained even if it does enter the labyrinth seal.

[Drain section]
3, the drain portion 12A is configured in a predetermined circumferential region on the road surface side of the seal member 12. In the present embodiment, the drain portion 12A is located at the bottom of the seal member 12 and is configured in a region that is approximately one-quarter of the circumferential length of the seal member 12. The circumferential length of the drain portion 12A increases from the radially inner side to the radially outer side of the seal member 12.

As shown in Figures 3 and 4, the first side lip 12b and second side lip 12c are not formed in the region where the drain portion 12A of the seal member 12 is formed. In other words, the first side lip 12b and second side lip 12c are missing from the drain portion 12A of the seal member 12, and the protrusion 13d and the seal member 12 do not overlap when viewed radially on the outer diameter side of the third side lip 12.

By providing the drain portion 12A in the seal member 12 in this way, even if muddy water seeps into the interior of the outer seal member 10, the centrifugal force generated when the hub wheel 3 rotates relative to the outer ring 2 makes it easier for the infiltrating muddy water to be discharged to the outside of the outer seal member 10 through the drain portion 12A. The muddy water discharged to the outside through the drain portion 12A is easily discharged to the outside of the seal member 12 through the gap between the protruding portion 13d of the metal ring 13 and the base portion 12a of the seal member 12 without being obstructed by the second side lip 12c and the first side lip 12b.

This prevents muddy water that has seeped into the interior of the outer seal member 10 from drying out, preventing seal lips such as the first side lip 12b and second side lip 12c from being worn down by dried mud, and enabling the muddy water resistance of the outer seal member 10 to be maintained for an extended period of time.

In this embodiment, the drain portion 12A is located in the lower half of the outer seal member 10, which faces the road surface, but it can also be configured in the upper half, which faces away from the road surface. Even when the drain portion 12A is configured on the side of the outer seal member 10 away from the road surface, it is possible to discharge muddy water that has seeped into the outer seal member 10 to the outside by the centrifugal force generated when the hub wheel 3 rotates relative to the outer ring 2.

However, if the drain portion 12A is configured on the road surface side of the outer seal member 10, gravity will also promote the discharge of muddy water that has seeped inside, in addition to the centrifugal force generated when the hub wheel 3 rotates relative to the outer ring 2. Therefore, it is preferable to configure the drain portion 12A on the road surface side of the outer seal member 10.

The drain portion 12A of the outer seal member 10 shown in Figure 4 does not have a first side lip 12b or a second side lip 12c.

However, as shown in Figure 5, the drain portion 12A of the outer seal member 10 may also be configured so that it does not only have the first side lip 12b, but also has the second side lip 12c. Even in this configuration, the protrusion 13d of the metal ring 13 and the seal member 12 do not overlap radially on the outer diameter side of the protrusion 13d, making it easier for muddy water that has seeped into the interior of the outer seal member 10 to be discharged to the outside.

Also, as shown in Figure 6, the drain portion 12A of the outer seal member 10 can be configured so that only the second side lip 12c is not formed, but the first side lip 12b is formed. Even in this configuration, the protrusion 13d of the metal ring 13 and the seal member 12 do not overlap when viewed from the radial direction between the first side lip 12b and the third side lip 12d, making it easier for muddy water that has seeped into the interior of the outer seal member 10 to be discharged to the outside.

Furthermore, in the drain portion 12A of the outer seal member 10 shown in Figure 3, the circumferential length of the drain portion 12A increases from the radially inner side to the radially outer side of the seal member 12. However, as shown in Figure 7, the drain portion 12A of the outer seal member 10 can also be configured so that the circumferential length of the drain portion 12A decreases from the radially inner side to the radially outer side of the seal member 12.

By configuring the drain portion 12A so that its circumferential length decreases radially outward, the area without a labyrinth seal becomes smaller radially outward, preventing muddy water from penetrating into the outer seal member 10 through the drain portion 12A. This further improves the muddy water resistance of the outer seal member 10.

In this embodiment, the wheel bearing device 1 is configured as a wheel bearing device 1 with a third-generation structure in which the inner raceway surface 3c is formed directly on the outer periphery of the hub wheel 3, but this is not limited to this and it may also be a second-generation structure in which a pair of inner rings 4 are press-fitted and fixed to the hub wheel 3.

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 Wheel bearing device 2 Outer ring 2b Outer opening 2c (inner) outer raceway surface 2d (outer) outer raceway surface 3 Hub ring 3b Wheel mounting flange 3c Inner raceway surface 3d Base 4 Inner ring 4a Inner raceway surface 5 Inner ball row 6 Outer ball row 10 Outer seal member 11 Core metal 12 Seal member 12A Drain portion 12b First side lip 12c Second side lip 13 Metal ring 13a Disc portion 13d Protrusion

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 has a first seal lip extending from the core metal toward the wheel mounting flange and facing the wheel mounting flange with a gap therebetween, and a second seal lip extending from the core metal toward the wheel mounting flange at a position radially inward of the first seal lip and facing the metal ring with a gap therebetween,
the metal ring has a disk portion that contacts a base portion of the wheel mounting flange and faces the second seal lip, and a protruding portion that protrudes from a radially outer end of the disk portion toward the core metal and faces the seal member with a gap between the first seal lip and the second seal lip in the radial direction,
the first seal lip, the second seal lip, and the protruding portion overlap each other when viewed from a radial direction,
The seal member has a drain portion in which the first seal lip and the second seal lip are not formed in a predetermined circumferential region, and the protrusion does not overlap with the first seal lip and the second seal lip when viewed from the radial direction. The wheel bearing device according to claim 1, wherein the drain portion is located on the road surface side of the seal member. A wheel bearing device according to claim 1 or claim 2, wherein the circumferential length of the drain portion decreases from the radially inner side to the radially outer side.