JP2020085032A - Sealing device - Google Patents

Abstract

To provide a sealing device which can be improved in muddy water resistance.SOLUTION: A sealing device 15 comprises: a slinger 30 having a first cylinder part 31 fit to an external peripheral face of a hub shaft 11, and fixed to the hub shaft 11, a circular plate part 32 extending to the outside in a radial direction along a side face of a flange part 56 from an end part of the first cylinder part 31 at a vehicle outer-side, and a second cylinder part 33 extending to a vehicle inner-side from an external peripheral end part of the circular plate part 32; a core grid 25 fit to an end part of an outer ring 12 at the vehicle outer-side, and fixed to the outer ring 12; a seal lip 21 fixed to the core grid 25, and coming in slide-contact with the first cylinder part 31 and the circular plate part 32; and a cylindrical deflector 23 which is fixed to the core grid 25 and in which an external peripheral face is arranged opposite to an internal peripheral face of the second cylinder part 33, which therefore forms a labyrinth clearance S between the second cylinder part 33 and the deflector 23. An end face 33a of the second cylinder part 33 at the vehicle inner side is arranged on a plane flushed with an end face 23a of the deflector 23 at the vehicle inner side.SELECTED DRAWING: Figure 2

Description

The present invention relates to a sealing device.

In vehicles such as automobiles, a wheel bearing device (hub unit) is used to rotatably support wheels. The wheel bearing device includes an outer ring fixed to a suspension device on the vehicle body side, a hub shaft to which the wheel is attached, and a rolling element provided between the outer ring and the hub shaft. In addition, such a wheel bearing device is provided with a sealing device in order to prevent foreign matter such as muddy water from entering the inside of the bearing from the outside of the bearing (see, for example, Patent Document 1).

The sealing device described in Patent Document 1 includes a slinger fitted and fixed to the outer peripheral side of a hub shaft, a cored bar fitted and fixed to an end portion of the outer ring on the vehicle outer side, and a cored bar. A sealing member that is fixed and is in sliding contact with the slinger. The seal member has a lip extending from the vehicle outer side to the vehicle inner side along the outer peripheral surface of the outer ring, and extends radially outward of the lip from the radial outer end of the slinger to the vehicle inner side. The cylindrical parts are close and face each other. As a result, a labyrinth gap is formed between the lip and the cylindrical portion to prevent muddy water or the like from entering the sliding contact portion between the seal member and the slinger.

JP, 2017-172718, A

In the sealing device, a flow rate of muddy water or the like under the usage environment is assumed, and the anti-muddy water is secured based on the assumed flow rate. However, in recent years, in order to be able to cope with a more severe use environment, a larger amount of mud water or the like has been adopted than the conventional amount. Therefore, it is desired to improve the mud water resistance more than ever before.

The present invention has been made in view of such problems, and an object thereof is to provide a sealing device capable of improving mud water resistance.

(1) In the present invention, a hub shaft having a flange portion on the vehicle outer side to which a wheel is attached, and an outer ring arranged radially outward of an outer peripheral surface of the hub shaft on the vehicle inner side of the flange portion, A plurality of rolling elements provided between the hub shaft and the outer ring, and a sealing device used in a bearing device for a wheel, comprising: a hub shaft fitted to an outer peripheral surface of the hub shaft; A first cylindrical portion that is fixed, a disk portion that extends radially outward from the vehicle outer side end portion of the first cylindrical portion along the side surface of the flange portion, and a vehicle from the outer peripheral end portion of the disk portion. A slinger having a second cylindrical portion extending to the inner side, a core metal fitted to the vehicle outer side end portion of the outer ring and fixed to the outer ring, and a first cylindrical portion fixed to the core metal. Between the seal lip that is in sliding contact with at least one of the disc portions and the second cylindrical portion, which is fixed to the core metal and whose outer peripheral surface faces the inner peripheral surface of the second cylindrical portion. And a cylindrical deflector forming a labyrinth gap, the end surface of the second cylindrical portion on the vehicle inner side is disposed on the same surface as the end surface of the deflector on the vehicle inner side.

According to the sealing device configured as described in (1) above, the vehicle inner side end surface of the second cylindrical portion is arranged on the same plane as the vehicle inner side end surface of the deflector, so that muddy water or the like is generated. It is possible to effectively prevent the infiltration into the sliding contact portion between the seal lip and the slinger from between the second cylindrical portion and the deflector. This can improve the mud water resistance of the sealing device.
That is, the present inventor, as a result of repeated diligent research, focused on the second cylindrical portion and the deflector that form the labyrinth gap, and by arranging the end surfaces on the vehicle inner side of these members on the same plane, It has been found that it becomes difficult for muddy water or the like to enter the seal lip side from between the two members, and the present invention has been completed based on such findings.

(2) According to another aspect of the present invention, a hub shaft having a flange portion to which a wheel is attached is provided on a vehicle outer side, and a hub shaft is provided radially outward of a peripheral surface of the hub shaft on a vehicle inner side than the flange portion. A sealing device used in a bearing device for a wheel, comprising: an outer ring arranged; and a plurality of rolling elements provided between the hub shaft and the outer ring, which is fitted to an outer peripheral surface of the hub shaft. And a first cylindrical portion fixed to the hub axle, a disk portion that extends radially outward from the vehicle outer side end portion of the first cylindrical portion along the side surface of the flange portion, and the disk portion. A slinger having a second cylindrical portion extending from the outer peripheral end to the vehicle inner side, a cored bar fitted to the vehicle outer side end of the outer ring and fixed to the outer ring, and fixed to the cored bar, The seal lip, which is in sliding contact with at least one of the first cylindrical portion and the disc portion, is fixed to the core metal, and the outer peripheral surface is arranged to face the inner peripheral surface of the second cylindrical portion. A cylindrical deflector that forms a labyrinth gap between the two cylindrical portions, and a vehicle inner side end surface of the second cylindrical portion is a predetermined length longer than a vehicle inner side end surface of the deflector. It is located on the side.

According to the sealing device configured as described above in (2), the end surface of the second cylindrical portion on the vehicle inner side is arranged on the vehicle outer side by a predetermined length than the end surface of the deflector on the vehicle inner side. It is possible to effectively prevent muddy water and the like from entering between the second cylindrical portion and the deflector into the sliding contact portion between the seal lip and the slinger. This can improve the mud water resistance of the sealing device.
That is, the present inventor, as a result of intensive studies, focused on the second cylindrical portion and the deflector forming the labyrinth gap, and the end surface of the second cylindrical portion on the vehicle inner side was compared with the end surface on the vehicle inner side of the deflector. It was also found that by arranging a predetermined length on the vehicle outer side, it becomes difficult for muddy water or the like to enter the seal lip side from between these members, and the present invention has been completed based on such findings.

The predetermined length is preferably 1.0 mm.
In this case, the mud water resistance of the sealing device can be effectively improved.

According to the sealing device of the present invention, mud water resistance can be improved.

It is a sectional view showing a bearing device for wheels provided with a sealing device concerning a 1st embodiment of the present invention. It is an expanded sectional view which shows the said sealing device. It is an expanded sectional view showing a sealing device concerning a 2nd embodiment of the present invention. It is explanatory drawing of the test device used for the evaluation test. It is a graph which shows the test result of an evaluation test.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a cross-sectional view showing a wheel bearing device according to an embodiment of the present invention. The wheel bearing device (hub unit) 10 is attached to, for example, a suspension device (knuckle) on the vehicle body side of an automobile, and rotatably supports the wheels. The wheel bearing device 10 includes a hub shaft 11, an outer ring 12, a rolling element 13, a cage 14, and sealing devices 15 and 17.

The outer ring 12 is a cylindrical member, and is made of, for example, carbon steel for machine structure. The outer ring 12 has a cylindrical outer ring main body 51 and a fixing flange portion 52 extending radially outward from the outer ring main body 51. By fixing the flange portion 52 to a knuckle (not shown) that is a vehicle body side member, the wheel bearing device 10 including the outer ring 12 is fixed to the knuckle.

In the state where the wheel bearing device 10 is fixed to the vehicle body side, the wheel mounting flange portion 56 side, which will be described later, of the hub axle 11 is the outside of the vehicle. That is, the left side (flange portion 56 side) of FIG. 1 is the vehicle outer side, and the right side of FIG. 1 is the vehicle inner side. Further, the left-right direction of FIG. 1 is the axial direction of the wheel bearing device 10.

The hub axle 11 has a shaft main body 55, a flange portion 56 to which a wheel is attached, and an inner ring member 57. These are made of, for example, carbon steel for machine structural use. The shaft body 55 is a shaft member that is long in the axial direction. The flange portion 56 is provided so as to extend radially outward from the vehicle outer side of the shaft main body portion 55 and has an annular shape. A plurality of holes are formed in the flange portion 56 along the circumferential direction, and a wheel mounting bolt 69 is attached to the holes. A brake rotor is attached to the flange portion 56 in addition to the wheels (not shown). The inner ring member 57 is an annular member, and is fitted and attached to the vehicle inner side of the shaft body 55. A shaft raceway surface 11a is formed on the outer peripheral surface of the shaft main body 55 on the vehicle outer side, and an inner raceway surface 11b is formed on the outer peripheral surface of the inner ring member 57.

The outer ring 12 is arranged radially outward of the outer peripheral surface of the hub axle 11 on the vehicle inner side of the flange portion 56. An outer ring raceway surface 12a on the vehicle outer side and an outer ring raceway surface 12b on the vehicle inner side are formed on the inner periphery of the outer ring 12.

The outer raceway raceway surface 11a and the outer raceway raceway surface 12a on the outer side of the vehicle face each other in the radial direction, and balls as rolling elements 13 are arranged between these raceway surfaces 11a and 12a. Similarly, the inner ring raceway surface 11b and the outer ring raceway surface 12b on the vehicle inner side are opposed to each other in the radial direction, and balls, which are rolling elements 13, are arranged between these raceway surfaces 11b and 12b. As a result, the rolling elements (balls) 13 are provided in two rows.

The rolling elements (balls) 13 in each row are held by an annular cage 14. The retainer 14 on the vehicle outer side holds the plurality of rolling elements 13 included in the rolling element row located on the vehicle outer side at intervals in the circumferential direction. The vehicle inner side retainer 14 holds the plurality of rolling elements 13 included in the rolling element row located on the vehicle inner side at intervals in the circumferential direction. The cage 14 can be made of resin, for example. In this way, the plurality of rolling elements 13 are held by the retainer 14 between the hub shaft 11 and the outer ring 12, so that the outer ring 12 is positioned outside the hub shaft 11 (shaft body 55) in the radial direction. It is provided concentrically with the shaft 11.

The vehicle inner side sealing device 17 includes an annular seal member 40 and an annular slinger 50. The seal member 40 is fitted and attached on the inner side of the outer ring 12 (outer ring body 51) and on the vehicle inner side. The slinger 50 is fitted and attached to the outer peripheral surface of the inner ring member 57 in an interference fit state. A part of the seal member 40 is brought into sliding contact with the slinger 50, whereby foreign matter can be prevented from entering the bearing from the outside on the vehicle inner side. The inside of the bearing is a region between the hub shaft 11 and the outer ring 12, in which two rows of rolling elements 13 are provided.

The vehicle outer side sealing device 15 suppresses foreign matter from entering the inside of the bearing from the outside of the vehicle outer side, and includes an annular seal member 20 and an annular slinger 30. The seal member 20 is fitted and attached on the inner side of the outer ring 12 (outer ring body 51) and on the vehicle outer side. The slinger 30 is fitted and mounted on the outer peripheral surface of the shaft main body 55 on the vehicle outer side in an interference fit state.

FIG. 2 is an enlarged cross-sectional view showing the sealing device 15. The seal member 20 includes a metal cored bar 25 and a rubber seal main body 26. The core metal 25 is fitted and attached to the inner peripheral surface of the end portion 12c on the vehicle outer side of the outer ring 12 (outer ring body 51) in an interference fit state. The seal body 26 is fixed (vulcanized and bonded) to the core metal 25, and has a seal lip 21 and a cylindrical deflector 23. The seal lip 21 has an annular first lip 21a and an annular second lip 21b.

The first lip 21a extends from the radially inner end portion of the cored bar 25 to the vehicle outer side and radially outwardly, and is in sliding contact with a disk portion 32 (described later) of the slinger 30 in the axial direction. As a result, the first lip 21a has a function of preventing foreign matter such as muddy water (hereinafter simply referred to as “muddy water”) from entering the inside of the bearing through the slinger 30. Note that, in FIG. 2, the first lip 21a is shown in a free state.

The second lip 21b extends from the radially inner end of the core metal 25 toward the vehicle inner side and radially inward, and is in radial contact with the first cylindrical portion 31 (described later) of the slinger 30. As a result, the second lip 21b mainly has a function of preventing the grease inside the bearing from flowing out.

The deflector 23 extends axially from the radially outer end portion of the cored bar 25, and the inner peripheral surface on the vehicle inner side is in close contact with the outer peripheral surface of the outer ring main body 51. The end surface of the deflector 23 on the vehicle outer side is arranged axially with respect to the disk portion 32 of the slinger 30.

The slinger 30 is a metal annular member and has a first cylindrical portion 31, a disc portion 32, and a second cylindrical portion 33. The first cylindrical portion 31 is a cylindrical member, and is fitted and attached to the outer peripheral surface of the shaft main body portion 55 on the vehicle outer side in a tight fit state.

The disk portion 32 is an annular flat plate member, and extends radially outward from an end portion of the first cylindrical portion 31 on the vehicle outer side. The disk portion 32 is disposed along the side surface 56a of the flange portion 56 on the vehicle inner side and is in contact with the side surface 56a.

The second cylindrical portion 33 extends from the outer peripheral end of the disc portion 32 toward the vehicle inner side. The second cylindrical portion 33 is arranged close to the outside in the radial direction of the deflector 23. Thereby, the outer peripheral surface of the deflector 23 and the inner peripheral surface of the second cylindrical portion 33 are arranged to face each other, and a labyrinth gap S is formed between the deflector 23 and the second cylindrical portion 33. The labyrinth gap S has a function of suppressing intrusion of muddy water or the like from the outside into the sliding contact portion between the first lip 21a and the disc portion 32.

In the present embodiment, the vehicle inner side end surface 33a of the second cylindrical portion 33 is the vehicle inner side end surface 23a of the deflector 23 in order to further prevent muddy water and the like from entering the sliding contact portion through the labyrinth gap S. It is located on the same plane as.

FIG. 3 is an enlarged cross-sectional view showing a sealing device according to the second embodiment of the present invention. In the sealing device 15 of the present embodiment, the axial length of the second cylindrical portion 33 is shorter than the axial length of the second cylindrical portion 33 in the first embodiment. That is, in the present embodiment, in order to further suppress the entry of muddy water or the like from the labyrinth gap S into the sliding contact portion, the end surface 33a of the second cylindrical portion 33 on the vehicle inner side is located on the vehicle inner side of the deflector 23. It is arranged on the vehicle outer side by a predetermined length L in the axial direction from the end face 23a.

The predetermined length L is preferably set to 1.0 mm. This is because if the predetermined length L is less than 1.0 mm or longer than 1.0 mm, the muddy water resistance performance deteriorates, and muddy water or the like easily enters from the labyrinth gap S to the sliding contact portion.
Note that the description of the second embodiment is omitted as in the first embodiment.

FIG. 4 is an explanatory diagram of a test device used in the evaluation test conducted by the present inventor in order to verify the effect obtained by the sealing device 15 of the present embodiment. The test device 90 includes a rotating shaft 91 corresponding to a hub shaft, a cylindrical outer member 92 corresponding to an outer ring, a water injection nozzle 93 disposed above the outer member 92 to inject muddy water, and an outer member 92. And a water receiving container 94 arranged inside in the radial direction.

In the present evaluation test, the rotary shaft 91 was placed between the rotary shaft 91 of the test device 90 and the outer member 92 in a state where the three types of sealing devices of Example 1, Example 2 and Comparative Example described below were respectively arranged. When muddy water was injected from the water injection nozzle 93 while rotating, the amount of infiltration of muddy water that passed through the sealing device and accumulated in the water receiving container 94 was compared.

Example 1 A sealing device in which the end surface of the second cylindrical portion on the vehicle inner side is arranged on the same plane as the end surface of the deflector on the vehicle inner side (corresponding to the sealing device of the first embodiment).
Example 2 A sealing device in which the end surface of the second cylindrical portion on the vehicle inner side is arranged on the vehicle outer side by 1.0 mm from the end surface of the deflector on the vehicle inner side (corresponding to the sealing device of the second embodiment).
Comparative Example: Sealing device in which the end surface of the second cylindrical portion on the vehicle inner side is arranged on the vehicle inner side by 1.0 mm from the end surface of the deflector on the vehicle inner side (corresponding to a conventional sealing device).
Note that none of the above three types of sealing devices has the first seal lip and the second seal lip.

This evaluation test was conducted under the following test conditions.
Composition of muddy water: 125g of JIS 8 types of Kanto loam suspended in 1L of water Muddy water injection rate: 7.2L/min
Number of water injection nozzles 93: 2 (water injection amount per one: 3.6 L/min)
Inner diameter of each water injection nozzle 93: 12.7 mm
Circumferential position of each water injection nozzle 93 with respect to the outer member 92: One water injection nozzle 93 is inclined from the position directly above the outer member 92 to the one side in the circumferential direction by 30°, and the other water injection nozzle 93 is the outer member. Position inclining 30° to the other side in the circumferential direction from a position right above 92. Position in the radial direction of each water injection nozzle 93 with respect to the outer member 92: Position 32 mm radially outward from the outer peripheral surface of the outer member 92 Rotating shaft 91 Rotation speed: measured every 100 rpm between 0 rpm and 500 rpm Measurement time: 1 min

FIG. 5 is a graph showing the test results of this evaluation test. As shown in FIG. 5, in each of Example 1, Example 2 and Comparative Example, the lower the rotation speed of the rotating shaft 91, the larger the amount of muddy water intrusion, but the muddy water infiltration of Example 1 and Example 2 It can be seen that the amount is smaller than the infiltration amount of muddy water in the comparative example. Particularly, when the rotation speed of the rotating shaft 91 is 100 rpm or less, the difference between the amount of entering the muddy water of Examples 1 and 2 and the amount of entering the muddy water of the comparative example is 40 g or more, and the rotating speed of Example 1 and Example 2 is It can be seen that the lower the rotation speed of the shaft 91, the more effectively the amount of muddy water infiltration can be reduced.

As described above, according to the sealing device 15 of the first embodiment shown in FIG. 2, the vehicle inner side end surface 33a of the second cylindrical portion 33 of the slinger 30 is the vehicle inner side end surface 23a of the deflector 23 of the seal member 20. By being arranged on the same surface, it is possible to effectively prevent muddy water and the like from entering between the second cylindrical portion 33 and the deflector 23 into the sliding contact portion between the seal lip 21 and the slinger 30. it can. Thereby, the mud water resistance of the sealing device 15 can be improved.

According to the sealing device 15 of the second embodiment shown in FIG. 3, the end surface 33a on the vehicle inner side of the second cylindrical portion 33 is separated from the end surface 23a on the vehicle inner side of the deflector 23 by a predetermined length L. By being disposed on the side, it is possible to effectively prevent muddy water and the like from entering between the second cylindrical portion 33 and the deflector 23 into the sliding contact portion between the seal lip 21 and the slinger 30. Thereby, the mud water resistance of the sealing device 15 can be improved.

The bearing device for a wheel according to the present invention is not limited to the hub unit shown in the above embodiment, and can be applied to hub units of other forms. For example, the present invention can be applied to a hub unit that uses tapered rollers instead of balls as rolling elements.
Further, the seal lip 21 of the above-described embodiment has the first lip 21a and the second lip 21b, but it suffices to have at least one lip.

The embodiments disclosed this time are to be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above meaning but by the scope of the claims, and is intended to include the meaning equivalent to the scope of the claims and all modifications within the scope.

10 Wheel Bearing Device 11 Hub Shaft 12 Outer Ring 13 Rolling Element 21 Seal Lip 23 Deflector 23a End Face 25 Core Bar 30 Slinger 31 First Cylindrical Part 32 Disc Part 33 Second Cylindrical Part 33a End Face 56 Flange Part L Labyrinth Gap

Claims (3)

A hub shaft having a flange portion on the vehicle outer side to which wheels are attached, an outer ring arranged radially outward of an outer peripheral surface of the hub shaft on the vehicle inner side of the flange portion, the hub shaft and the outer ring. A plurality of rolling elements provided between, and a sealing device used for a wheel bearing device including:
A first cylindrical portion fitted to the outer peripheral surface of the hub shaft and fixed to the hub shaft, and extends radially outward from a vehicle outer side end portion of the first cylindrical portion along a side surface of the flange portion. A slinger having a disc portion and a second cylindrical portion extending from the outer peripheral end of the disc portion toward the vehicle inner side;
A cored bar fitted to the vehicle outer side end of the outer ring and fixed to the outer ring,
A seal lip fixed to the core metal and in sliding contact with at least one of the first cylindrical portion and the disc portion;
A cylindrical deflector fixed to the core metal and having an outer peripheral surface facing the inner peripheral surface of the second cylindrical portion to form a labyrinth gap with the second cylindrical portion. ,
The vehicle inner side end face of the second cylindrical portion is arranged on the same plane as the vehicle inner side end face of the deflector. A hub shaft having a flange portion on the vehicle outer side to which a wheel is attached, an outer ring arranged radially outward of an outer peripheral surface of the hub shaft on the vehicle inner side of the flange portion, the hub shaft and the outer ring. A plurality of rolling elements provided between, and a sealing device used for a wheel bearing device including:
A first cylindrical portion fitted to the outer peripheral surface of the hub shaft and fixed to the hub shaft, and extends radially outward from a vehicle outer side end portion of the first cylindrical portion along a side surface of the flange portion. A slinger having a disc portion and a second cylindrical portion extending from the outer peripheral end of the disc portion toward the vehicle inner side;
A cored bar fitted to the vehicle outer side end of the outer ring and fixed to the outer ring,
A seal lip fixed to the core metal and in sliding contact with at least one of the first cylindrical portion and the disc portion;
A cylindrical deflector fixed to the core metal and having an outer peripheral surface facing the inner peripheral surface of the second cylindrical portion to form a labyrinth gap with the second cylindrical portion. ,
The vehicle inner side end surface of the second cylindrical portion is arranged on the vehicle outer side by a predetermined length from the vehicle inner side end surface of the deflector. The sealing device according to claim 2, wherein the predetermined length is 1.0 mm.

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