JP2020002970A - Bearing device for wheel - Google Patents

Abstract

To provide a bearing device for a wheel which can inhibit a lip of an elastic body of a seal ring from being immersed in mud water accumulated between the seal ring and a dust cover and thereby inhibit wear of the lip while maintaining a foreign object entry prevention function of the dust cover.SOLUTION: A bearing device 1 for a wheel includes: an inner member 3 to which a wheel is attached; an outer member 2 supporting the inner member 3 through rolling elements 4; a slinger 7 having a fitting part 71 fitted in the inner member 3 and a standing plate part 72 extending to the radial outer side; a seal ring 6 having a core grid 61 attached to the outer member 2 and an elastic body 62 formed with an outer lip 621 which slidably contacts with the standing plate part 72 of the slinger 7; and a dust cover 8 having a shield part 82 extending from a fitting part 81 fitted on the outer member 3 to the radial inner side. The dust cover 8 has an annular shape in which a through hole 80 is formed at a center part of the shield part 82. An inner diameter of the through hole 80 is smaller than an outer diameter of the slinger 7 and larger than an outer diameter of the outer lip 621.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a wheel bearing device that supports a wheel.

  Conventionally, an inner member having a flange to which a wheel is mounted, and a wheel bearing device having a cylindrical outer member rotatably supporting the inner member through a plurality of rolling elements, an inner member and Seal rings are attached to both ends of the outer member in order to prevent foreign matter from entering the outer member. In the seal ring, an elastic body having a plurality of lips is formed integrally with a cored bar, and the plurality of lips are in sliding contact with a slinger mounted on the inner member. In the wheel bearing devices described in Patent Documents 1 and 2, a dust cover is further attached to an outer member in order to suppress entry of foreign matter between the slinger and the lip of the elastic body.

  The wheel bearing device described in Patent Literature 1 is used for a driven wheel to which no driving force is transmitted (for example, a rear wheel of a front wheel drive vehicle), and an inner member is inserted inside an annular dust cover. The dust cover is formed from a cold-rolled steel plate into an L-shaped cross section by press working, and has a cylindrical fitting portion pressed into the outer periphery of the end of the outer member, and one end of the fitting portion. A disk-shaped shielding portion extending inward in the radial direction. A slight gap is formed between the tip of the shield and the inner member.

  The wheel bearing device (bearing unit) described in Patent Literature 2 is used for a driving wheel to which driving force is transmitted, and transmits driving force to an inner member inside an annular dust cover (fitting cylinder). The housing of the constant velocity joint is inserted. The dust cover includes a fitting tubular portion fitted to an outer member (outer ring), and an inward flange bent from a base end edge of the fitting tubular portion, and a distal end of the inward flange and the inner member ( A slight gap is formed between the inner ring and the inner ring.

JP 2014-13073 A (FIG. 1) JP-A-2003-254985

  In the wheel bearing device configured as described above, the wheels may splash up muddy water when the vehicle travels, and splashes of muddy water may stay between the dust cover and the seal ring. In this case, the lip of the elastic body of the seal ring may be immersed in the muddy water at the lower end portion in the vertical direction, and fine particles contained in the muddy water may promote abrasion of the lip. The present inventors have paid attention to this problem, and have earnestly studied the shape of the dust cover in which the lip of the elastic body of the seal ring is not immersed in the retained muddy water while maintaining the foreign matter intrusion suppression function of the dust cover. This has led to the present invention.

  That is, the object of the present invention is to prevent the lip of the elastic body of the seal ring from being immersed in the muddy water retained between the dust cover and the lip while maintaining the foreign matter intrusion suppression function of the dust cover. It is an object of the present invention to provide a wheel bearing device capable of suppressing the occurrence of a wheel.

  The present invention, in order to achieve the above object, an inner member having a flange to which wheels are attached, a cylindrical outer member rotatably supporting the inner member via a plurality of rolling elements, A fitting portion fitted to the inner member, and a slinger having an annular standing plate portion extending radially outward from the fitting portion; a core bar attached to the outer member; and the core bar. A seal ring having an elastic body formed integrally and having a lip formed in sliding contact with the upright plate portion of the slinger, a fitting portion externally fitted to an end of the outer member, and the fitting portion. A cover member that has a shielding portion that extends inward in the radial direction, and a cover member that suppresses intrusion of foreign matter from a gap on the outer peripheral side of the upright plate portion of the slinger by the shielding portion. A through-hole formed in the center of the part, The inner diameter of the hole is smaller than the outer diameter of the slinger, and larger than the outer diameter of the lip, provides a wheel bearing device.

  ADVANTAGE OF THE INVENTION According to the bearing device for wheels which concerns on this invention, the lip of the elastic body of a seal ring can be suppressed from being immersed in the muddy water accumulated between the dust covers, while maintaining the foreign substance intrusion suppression function of the dust cover. Thus, it is possible to suppress wear of the lip.

It is a sectional view showing the bearing device for wheels concerning a 1st embodiment of the present invention. (A) is an explanatory view showing the lower end of the dust cover viewed from the vehicle inner side. (B) is a partial enlarged view of FIG. 1 corresponding to the part shown in (a). (A) is an explanatory view showing a lower end of a dust cover of a wheel bearing device according to a second embodiment of the present invention. (B) is a sectional view showing a cross section of the lower end portion of the dust cover together with its peripheral portion.

[First Embodiment]
A first embodiment of the present invention will be described with reference to FIGS. It should be noted that the embodiments described below are given as preferred specific examples for carrying out the present invention. For this reason, there are portions specifically illustrating various technical items that are technically preferable, but the technical scope of the present invention is not limited to these specific embodiments.

(Overall configuration of wheel bearing device)
FIG. 1 is a cross-sectional view showing the overall configuration of the wheel bearing device according to the first embodiment of the present invention. FIG. 1 shows a wheel bearing device mounted on a vehicle together with its peripheral portion. In FIG. 1, the lower side of the drawing corresponds to the ground side (vertical direction lower side) in the up-down direction when the vehicle is mounted.

  The wheel bearing device 1 rotatably supports a wheel 11 together with a brake rotor 12 with respect to a knuckle 10 constituting a suspension system of a vehicle. FIG. 1 shows the wheel 11 and a part of the brake rotor 12. Hereinafter, in the wheel bearing device 1, the side to which the wheel 11 is attached (the left side in FIG. 1) is referred to as a vehicle outer side, and the opposite side (the right side in FIG. 1) is referred to as a vehicle inner side.

  The wheel bearing device 1 includes a cylindrical outer member 2 fixed to a knuckle 10, an inner member 3 to which the wheel 11 and the brake rotor 12 are attached, and between the outer member 2 and the inner member 3. The plurality of rolling elements 4 disposed, the retainers 41 and 42 holding the plurality of rolling elements 4, and the vehicle outer side and the vehicle for preventing foreign matter from entering between the outer member 2 and the inner member 3. Seal rings 5 and 6 on the inner side, a slinger 7 attached to an end of the inner member 3 on the vehicle inner side, and a dust cover as a cover member attached to an end of the outer member 2 on the inner side of the vehicle 8 is provided.

  The outer member 2 includes a cylindrical base 21, a plurality of vehicle body mounting flanges 22 for mounting to the knuckle 10 on the vehicle body side, and an extending portion 23 extending to the vehicle inner side of the vehicle body mounting flange 22. And the inner member 3 is rotatably supported via a plurality of rolling elements 4. FIG. 1 illustrates one vehicle body mounting flange 22 among the plurality of vehicle body mounting flanges 22. Each of the plurality of vehicle body mounting flanges 22 has a bolt insertion hole through which the bolt 13 screwed to the knuckle 10 is inserted. Two outer raceway surfaces 2a and 2b for rolling the rolling element 4 are formed on the inner periphery of the base 21 in parallel with each other along the circumferential direction.

  The inner member 3 is rotatable about the rotation axis O with respect to the outer member 2, and two inner raceway surfaces 3 a and 3 b for rolling the rolling elements 4 are provided on the outer periphery of the inner member 3. They are formed parallel to each other along the direction. A plurality of rolling elements 4 are arranged between the outer raceway surface 2a and the inner raceway surface 3a and between the outer raceway surface 2b and the inner raceway surface 3b, respectively. Hereinafter, a direction parallel to the rotation axis O is referred to as an axial direction.

  In the present embodiment, the inner member 3 includes a hub wheel 31 and an annular inner ring member 32. The hub wheel 31 includes a wheel mounting flange 311 to which the wheel 11 and the brake rotor 12 are mounted, a body 313 disposed inside the outer member 2, and a connecting portion 312 connecting the wheel mounting flange 311 and the body 313. And are integrally provided. A plurality of press-fit holes 311a into which hub bolts 14 for fixing the wheel 11 and the brake rotor 12 are press-fitted are formed in the wheel mounting flange 311.

  The hub portion 14 of the hub bolt 14 has a shaft portion 141 having an external thread formed therein, which is press-fitted into the press-fitting hole 311a, and the head portion 142 is in contact with a side surface of the wheel mounting flange 311 on the vehicle inner side. The shaft 141 of the hub bolt 14 is inserted into an insertion hole 110 formed in the wheel of the wheel 11 and an insertion hole 120 formed in the brake rotor 12, and the wheel nut 15 is screwed to a tip end thereof.

  The trunk portion 313 of the hub wheel 31 has a large-diameter portion 314 on the vehicle outer side and a small-diameter portion 315 of the vehicle inner. The inner raceway surface 3a is formed on the outer peripheral surface of the large diameter portion 314, and the inner race member 32 is fitted on the outer peripheral surface of the small diameter portion 315. An inner raceway surface 3b is formed on the outer peripheral surface of the inner race member 32.

  A through-hole 310 is formed in the center of the hub wheel 31 so as to pass through the body 313 in the axial direction. A spline fitting portion 310a is formed on the inner surface of the through hole 310, and the stem portion 91 of the joint member 9 of the drive shaft fits into the spline fitting portion 310a so as to be relatively non-rotatable. The joint member 9 has a cup portion 92 having a larger diameter than the stem portion 91. The end portion of the cup portion 92 on the vehicle outer side is in contact with the inner race member 32. The stem portion 91 has a male screw portion 911 at the end on the vehicle outer side, and the nut 90 is screwed into the male screw portion 911.

  In the present embodiment, the rolling element 4 is a sphere, but is not limited thereto and may be a tapered roller. Further, in the present embodiment, the inner member 3 has one inner ring member 32, but the present invention is not limited to this, and the inner member 3 has two inner ring members, and one of the inner ring members The inner raceway surface 3a may be formed, and the inner raceway surface 3b may be formed on the other inner race member.

  Next, the configurations of the seal ring 6, the slinger 7, and the dust cover 8 on the vehicle inner side will be described in detail with reference to FIGS. The seal ring 6, the slinger 7, and the dust cover 8 prevent foreign matter from entering the space between the outer member 2 and the inner member 3 from the vehicle inner side. FIG. 2A illustrates a lower end portion (an end portion on the ground side in a vehicle mounted state) of the dust cover 8 as viewed from the vehicle inner side. FIG. 2B is a partially enlarged view of FIG. 1 corresponding to the portion shown in FIG.

  The slinger 7 is made of a metal such as stainless steel, for example, and integrally has a fitting portion 71 fitted to the inner member 3 and an annular standing plate portion 72 extending radially outward from the fitting portion 71. I have. The fitting portion 71 has a cylindrical shape, and is fitted to the end of the inner ring member 32 by press fitting. The upright plate portion 72 projects radially outward from an end of the fitting portion 71 on the vehicle inner side, perpendicular to the fitting portion 71.

  The seal ring 6 includes a metal core 61 attached to the outer member 2 and an elastic body 62 formed integrally with the metal core 61. The cored bar 61 has a cylindrical fitting portion 611 that is press-fitted into the inner peripheral surface 23a of the extension portion 23 of the outer member 2 and a radially inner portion of the fitting portion 611 from an end portion of the fitting portion 611 on the vehicle outer side. And a support portion 612 that extends in the direction to support the elastic body 62.

  The elastic body 62 is made of, for example, a rubber such as nitrile rubber or fluorine rubber, and is integrally joined to the cored bar 61 by, for example, vulcanization bonding. Further, the elastic body 62 has an outer lip 621 that slides on a side surface 72a of the upright plate portion 72 of the slinger 7 on the vehicle outer side, and first and second slides that slide on an outer peripheral surface 71a of the fitting portion 71 of the slinger 7. Inner lips 622 and 623 are formed.

  The dust cover 8 is formed, for example, by pressing a metal plate such as stainless steel, and extends radially inward from the cylindrical fitting portion 81 fitted to the end of the outer member 2. The shield 82 is integrally provided. The dust cover 8 suppresses the invasion of foreign matter from the gap on the outer peripheral side of the upright portion 72 of the slinger 7 by the shielding portion 82. The fitting portion 81 is press-fitted to the outer peripheral surface 23b of the extending portion 23 of the outer member 2. The shielding portion 82 has an annular contact portion 821 that contacts the end surface 23 c of the extension portion 23 on the vehicle inner side, and the vehicle inner portion of the upright plate portion 72 of the slinger 7 at a position shifted to the vehicle inner side from the contact portion 821. A disk portion 823 facing the side surface 72b on the side, and a tapered portion 822 between the contact portion 821 and the disk portion 823. The tapered portion 822 gradually moves away from the outer member 2 in the axial direction as it goes from the contact portion 821 to the disk portion 823.

  The dust cover 8 allows foreign substances to enter between the slinger 7 and the seal ring 6 from the gap C between the outer peripheral surface 72c of the upright plate portion 72 of the slinger 7 and the seal ring 6, that is, the vertical direction of the slinger 7 from the gap C. The entry of foreign matter into the space S between the plate portion 72 and the support portion 612 of the cored bar 61 is suppressed. When foreign matter such as dust enters the space S and is caught between the lip (the outer lip 621 and the first and second inner lips 622 and 623) of the elastic body 62 and the slinger 7, wear of the lip is reduced. It is because it is promoted.

  The dust cover 8 has an annular shape in which a circular through-hole 80 is formed at the center of the shielding portion 82. In the present embodiment, the through-hole 80 is formed in the disk portion 823 of the shielding portion 82. The center of the through hole 80 is on the rotation axis O, and penetrates the dust cover 8 in the axial direction. The joint member 9 (see FIG. 1) is inserted into the through hole 80.

The inner diameter of the through hole 80 is smaller than the outer diameter of the slinger 7 and larger than the outer diameter of the outer lip 621 of the elastic body 62. As shown in FIG. 2 (b), the inner radius of the through holes 80 around the rotation axis O and R _1, the outer radius of the slinger 7 and R _2, when the outer radius of the outer lip 621 and R _3, R ₁ is smaller than R ₂ and larger than R ₃ . Here, the outer diameter of the slinger 7 is the diameter of the outer peripheral surface 72c of the standing plate 72, and the outer diameter of the outer lip 621 is the sliding contact surface 621a where the outer lip 621 is in sliding contact with the standing plate 72 of the slinger 7. The diameter of the outer edge. In FIG. 2A, the outer peripheral surface 72c of the standing plate portion 72 and the outer contour line 621b of the sliding contact surface 621a are indicated by broken lines, and the inner peripheral surface 80a of the through hole 80 is indicated by solid lines.

  Since the inner diameter of the through hole 80 is smaller than the outer diameter of the slinger 7, it is difficult for foreign matter to enter from the gap C through the through hole 80. Further, since the inner diameter of the through hole 80 is larger than the outer diameter of the outer lip 621, even if muddy water or the like accumulates at the lower end portion in the vertical direction of the space S, the water surface is lower than the outer lip 621 and stays in the space S. The outer lip 621 is not immersed in the muddy water. FIG. 2B shows a state in which the muddy water W has accumulated up to the maximum water level in the space S. In this state, the water surface of the muddy water W is at the same height as the lowermost portion of the through hole 80 in the vertical direction.

(Operation and Effect of First Embodiment)
According to the first embodiment described above, since the inner diameter of the through hole 80 is larger than the outer diameter of the outer lip 621, muddy water does not accumulate above the lowermost portion of the through hole 80 in the vertical direction. This suppresses the wear of the outer lip 621 from being promoted by the fine particles contained in the muddy water. Further, since the inner diameter of the through hole 80 is smaller than the outer diameter of the slinger 7, foreign substances that enter the space S from the gap C via the through hole 80 are also suppressed. Thus, according to the first embodiment, the muddy water in which the outer lip 621 of the elastic body 62 of the seal ring 6 stays between the dust cover 8 and the dust cover 8 while maintaining the foreign matter intrusion suppressing function of the dust cover 8 is maintained. In the outer lip 621 can be suppressed. Thereby, the sealing performance of the seal ring 6 is maintained for a long time.

[Second embodiment]
Next, a second embodiment of the present invention will be described with reference to FIG. The wheel bearing device according to the second embodiment has a configuration in which a drain hole 820 for draining water collected between the seal ring 6 and the dust cover 8 is formed in the shielding portion 82 of the dust cover 8. Unlike the first embodiment, the other configuration is common to the first embodiment. Therefore, this difference will be described in detail, and the common parts to the first embodiment will be described repeatedly. Omitted.

  FIG. 3A is a cross-sectional view showing a cross section of a lower end portion of the dust cover 8 of the wheel bearing device according to the second embodiment together with a peripheral portion thereof. FIG. 3B is a view taken in the direction of arrow A in FIG. 3A and 3B, the same reference numerals as those in FIG. 2 denote the same components as those in the first embodiment.

  The shielding portion 82 of the dust cover 8 according to the present embodiment includes a contact portion 821, a tapered portion 822, and a disk portion 823, as in the first embodiment. In the present embodiment, a drain hole 820 is formed at the lower end of the tapered portion 822 in the vertical direction. The drain hole 820 is formed at one location in the circumferential direction of the dust cover 8, and penetrates the vehicle inner side surface and the vehicle outer side surface of the dust cover 8, like the through hole 80.

  According to the present embodiment, in addition to the operation and effect of the first embodiment, the water accumulated between the seal ring 6 and the dust cover 8 is drained by the drain hole 820, so that muddy water and the like can be discharged for a long time. The generation of rust due to stagnation over a long period of time is suppressed.

(Note)
As described above, the present invention has been described based on the embodiments. However, the above embodiments do not limit the invention according to the claims. Also, it should be noted that not all combinations of the features described in the embodiments are necessarily essential for solving the problem of the invention.

  In addition, the present invention can be appropriately modified and implemented without departing from the spirit thereof. For example, in the above-described embodiment, a case has been described in which the wheel bearing device supports the drive wheels to which the driving force of the drive source such as the engine is transmitted. However, the present invention is not limited to this, and it is also possible to apply the present invention to a wheel bearing device that supports a driven wheel to which no driving force is transmitted.

DESCRIPTION OF SYMBOLS 1 ... Bearing device for wheels 11 ... Wheel 2 ... Outer member 3 ... Inner member 311 ... Wheel mounting flange 4 ... Rolling element 6 ... Seal ring 61 ... Core 611 ... Fitting part 612 ... Support part 62 ... Elastic body 621 ... Outer lip 7 ... Slinger 71 ... Fitting part 72 ... Standing plate part 8 ... Dust cover 80 ... Through hole 81 ... Fitted part 82 ... Shielding part 820 ... Drain hole

Claims (2)

An inner member having a flange to which wheels are attached;
A cylindrical outer member rotatably supporting the inner member via a plurality of rolling elements,
A slinger having a fitting portion fitted to the inner member, and an annular standing plate portion extending radially outward from the fitting portion;
A core bar attached to the outer member, and a seal ring having an elastic body formed integrally with the core bar and having a lip formed in sliding contact with the upright portion of the slinger;
A fitting portion externally fitted to an end of the outer member, and a shielding portion extending radially inward from the fitting portion, and a gap on the outer peripheral side of the standing plate portion of the slinger by the shielding portion. And a cover member for suppressing intrusion of foreign matter from
The cover member has an annular shape in which a through hole is formed in a center portion of the shielding portion,
The inner diameter of the through hole is smaller than the outer diameter of the slinger, and larger than the outer diameter of the lip,
Bearing device for wheels. A drain hole for draining water accumulated between the seal ring and the cover member is formed in the shielding portion,
The wheel bearing device according to claim 1.

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