JP2005188632A - Bearing device for wheel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing device for a wheel capable of reducing bearing rotational torque while securing sealing performance. <P>SOLUTION: A closed space S faced by a bearing seal 5 of an annular space end between inner and outer members 2 and 3 is formed by a brake rotor 14 attached to the inner member 3, and a back plate 15 attached to the outer member 2. The brake rotor 14 and the back plate 15 do not contact, and a labyrinth seal 16 is formed between the two. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a wheel bearing device in an automobile or the like, and more particularly to a sealing structure thereof.

  Since wheel bearing devices installed in vehicles such as automobiles are in a harsh environment where they are exposed to the road surface, it is required to prevent dust and muddy water from entering from the outside. A high effect is also required for leakage prevention.

For this reason, for example, as shown in FIG. 4A, both ends of the annular space of the outer member 2 and the inner member 3 are sealed with seals 50. In order to improve the mud water resistance, a combination seal as shown in FIG. 5B is used for the seal 50 (for example, Patent Document 1). The combination seal 50 includes a slinger 51, which is a stainless steel seal member having an L-shaped cross section, a side lip 52a that contacts the upright plate portion 51a of the sling 51, and two radial lips 52b that contact the cylindrical portion 51b. , 52c and three sealing lips.
JP 2003-262231 A

The combination seal 50 is provided with a side lip 52a in order to improve the muddy water resistance. However, since the sliding resistance is large, the rotational torque of the seal 50 is large. This rotational torque is a major factor in bearing rotational torque. In addition, the use of the stainless steel part sling 51 increases the cost. Since the slinger 51 is a part for bringing the seal lip into contact with the seal lips 52a to 52c, if the rust is generated, the torque increase is greatly affected. Therefore, the slinger 51 cannot be replaced with an inexpensive iron plate and requires high processing accuracy.
In recent years, in wheel bearing devices, it has been desired to reduce bearing rotational torque in order to improve vehicle fuel efficiency. However, it is difficult to reduce bearing rotational torque with the combination seal 50 as described above.

  An object of the present invention is to provide a wheel bearing device that can reduce bearing rotational torque while ensuring sealing performance.

The wheel bearing device of the present invention includes an outer member having a double-row raceway surface on the inner periphery, an inner member having a raceway surface facing the raceway surface on the outer periphery, and a composite member interposed between the opposite raceway surfaces. In a wheel bearing device that includes a rolling element in a row and a bearing seal that seals an end of an annular space between the outer member and the inner member, and that rotatably supports the wheel with respect to the vehicle body,
The bearing seal between the outer member and the inner member is between a rotating body attached to the rotating member of the outer member and the inner member and a stationary member attached to the stationary member. A labyrinth seal is formed between the rotating body and the stationary member so as to form a closed space where the end of the annular space provided faces, the rotating body and the stationary member being in non-contact with each other, and serving as a path for opening the closed space to the outside. It is characterized by being formed between.

  According to this configuration, the ring between the outer member and the inner member is between the rotating body attached to the rotating member of the outer member and the inner member and the stationary member attached to the stationary member. A labyrinth seal is provided in the path that opens the closed space to the outside by forming a closed space facing the end of the space. It is reduced. Therefore, the bearing seal may have a simple configuration, and the friction torque due to the bearing seal can be reduced. Since the rotating body and the stationary member forming the closed space are not in contact with each other and only face each other via the labyrinth seal, the friction torque does not increase. For this reason, bearing rotational torque can be reduced while ensuring sealing performance. Note that the rotating body and the stationary member do not require strict rust prevention like the slinger in the combined bearing, and it is possible to reduce the cost by selecting an appropriate material as necessary. .

In this invention, the rotation side member may be a brake rotor, and the stationary member may be a back plate provided to face the brake rotor. The brake rotor may be a brake disc in a disc type brake or a brake drum in a drum type brake.
Since the brake rotor is a component that is generally attached to a rotating side member in a wheel bearing device, by using this brake rotor as a rotating body for forming the labyrinth seal, only a back plate is provided. The enclosed space and labyrinth seal can be formed. This avoids an increase in the number of members for forming the labyrinth seal. This avoids an increase in cost.

When the brake rotor is used for forming the closed space as described above, the outer member is a stationary member, the inner member is a rotating member, and the annular space between the outer member and the inner member. The outer end of the outer member faces the closed space between the rotating body and the stationary member, and on the outer side of the bearing than the bearing seal provided on the inboard side end of the annular space. You may provide the backup seal which seals the space between the outer periphery of the member attached to. The member attached to the inner member is, for example, a joint member constituting a constant velocity universal joint.
In the case of this configuration, the bearing seal can be simplified on the outboard side by forming the labyrinth seal, and the bearing seal can be simplified by providing a backup seal on the inboard side. Therefore, the bearing seal can be simplified on both the outboard side and the inboard side in the wheel bearing device, and the bearing rotational torque can be reduced while ensuring the sealing performance.

In the present invention, the bearing seal facing the closed space between the rotating body and the stationary member may be a contact seal having two seal lips.
The bearing seal that faces the closed space is sufficient for use in combination with the labyrinth seal, and if it has two seal lips, the required sealing performance can be ensured. The two seal lips are located inside and outside the bearing. For example, the inner seal lip functions as a grease stopper, and the outer seal lip functions as a dust or muddy water intrusion prevention function.

  The wheel bearing device according to the present invention includes an outer member and an inner member between a rotating body attached to a rotating member of an outer member and an inner member and a stationary member attached to a fixed member. Since the closed space where the end of the annular space between the side members faces is formed and the labyrinth seal is formed in the path that opens this closed space to the outside, the rotational torque of the bearing can be reduced while ensuring the sealing performance, thereby improving the fuel efficiency Can contribute.

  A first embodiment of the present invention will be described with reference to FIG. This embodiment is applied to a wheel bearing device for driving wheel support of an inner ring rotating type. The wheel bearing device 1 includes a ring-shaped outer member 2, an inner member 3 positioned on the inner diameter side, a double row rolling element 4, and an annular shape between the outer member 2 and the inner member 3. Bearing seals 5 and 6 are provided to seal both ends of the space RS. Each rolling element 4 of each row is held by a holder. In this specification, the side closer to the outer side in the vehicle width direction of the vehicle when attached to the vehicle is referred to as the outboard side, and the side closer to the center of the vehicle is referred to as the inboard side. In FIG. 1, the left side is the outboard side and the right side is the inboard side.

  The outer member 2 and the inner member 3 refer to the following in this specification. That is, the outer member 2 refers to a member having a raceway surface 2a formed on the inner periphery, and if there is a member corresponding to a bearing housing that fits on the outer periphery of the member forming the raceway surface 2a, the raceway surface 2a is formed. And a member corresponding to a bearing housing that supports the member. The inner member 3 is a member on the inner diameter side of the outer member 2 and formed with a raceway surface 3a on the outer periphery. If there is a member fitted on the inner periphery of the member forming the raceway surface 3a, the raceway surface is provided. This refers to a combination of the member formed with 3a and the member fitted to the inner periphery of this member.

  In this embodiment, the outer member 2 includes a bearing outer ring 8 and a suspension device constituting member 9 such as a knuckle that serves as a bearing housing to which the bearing outer ring 8 is fitted. The bearing outer ring 8 is formed of an integral member in which the raceway surface 2a is formed in a double row.

  The inner member 3 is configured by fixing a bearing inner ring 11 to the outer periphery of the hub ring 10. The bearing inner ring 11 includes two inner ring divided bodies 11A and 11B arranged in the width direction, and each inner ring divided body 11A and 11B is formed with a raceway surface 3a facing each raceway surface 2a of the outer member 2, respectively. Yes. The bearing inner ring 11, the bearing outer ring 8, and the double row rolling elements 4 constitute independent wheel bearings 12. The wheel bearing 12 in this embodiment is of the first generation type. The hub wheel 10 has flanges 10a on the outer periphery for attaching wheels (not shown), and hub bolts 13 are implanted at a plurality of locations in the circumferential direction of the flanges 10a. The flange 10 a is located on the outboard side with respect to the outer member 2. A brake rotor 14 as a rotating body is overlaid on a side surface of the flange 10a on the outboard side, and the brake rotor 14 is attached to the flange 10a by the hub bolt 13 together with a tire wheel rim (not shown) overlaid on the outer side. . In this embodiment, the brake rotor 14 is composed of a brake disc of a disc brake.

  Located on the inboard side of the brake rotor 14 that is a rotating body, a back plate 15 that is a stationary member is attached to the outer periphery of the suspension device component member 9, and an outer member is provided between the brake rotor 14 and the back plate 15. A closed space S facing the outboard side end of the annular space RS between 2 and the inner member 3 is formed. A labyrinth seal 16 serving as a path for opening the closed space S between the brake rotor 14 serving as the rotating body and the back plate 15 serving as the stationary member is not in contact with each other and is outside the closed space S. It is formed between the brake rotor 14 and the back plate 15. Specifically, the back plate 15 has a cylindrical flange portion 15 a that covers the outer periphery of the end portion of the disc-type brake rotor 14, and between the flange portion 15 a and the outer diameter surface of the brake rotor 14, A labyrinth seal 16 is configured.

The hub wheel 10 in the inner member 3 has an inner diameter hole 17 at the center, and a stem portion 19 a in one joint member 19 of the constant velocity universal joint 18 is inserted into the inner diameter hole 17. The joint member 19 sandwiches the hub wheel 10 together with the bearing inner ring 11 between a nut 19b screwed into a male thread portion formed at the tip of the stem portion 19a and the stepped surface 19c of the joint member 19, thereby the hub wheel 10 Is bound to.
Between the outer periphery of the joint member 18 and the inner periphery of the suspension device component member 9, a backup seal 20 is provided that is positioned outside the bearing relative to the bearing seal 6 on the inboard side. That is, the joint member 19 of the constant velocity universal joint 18 has an outer peripheral surface portion 19d serving as a shoulder portion of the stepped surface 19c, and an annular space between the outer peripheral surface portion 19d and the inner diameter surface of the suspension device component member 9. Is sealed with a backup seal 20. The backup seal 20 may be a contact seal or a non-contact seal such as a labyrinth seal.

  The bearing seals 5 and 6 have the same configuration. These bearing seals 5 and 6 are contact seals having two seal lips 22a and 22b, as shown in FIG. These bearing seals 5 and 6 are obtained by integrating a rubber-like elastic body 22 made of rubber or synthetic resin with an annular core metal 21 and are attached to the inner diameter surface of the outer member 2 by press fitting or the like. . The elastic body 22 is provided with the two sealing lips 22a and 22b. Each of the seal lips 22 a and 22 b is in sliding contact with the outer diameter surface of the inner member 3. The seal lips 22a and 22b are arranged inside and outside the bearing, and the inner seal lip 22a extends to the inside of the bearing to prevent grease leakage. The outer seal lip 22b has a tip that extends to the outside of the bearing and functions to prevent intrusion of dust and muddy water.

  According to the wheel bearing device 1 having this configuration, the annular space between the outer member 2 and the inner member 3 is constituted by the brake rotor 14 that is a rotating body attached to the hub wheel 10 and the back plate 15 that is a stationary member. A closed space S facing the end of the RS is formed. The closed space S is opened only by the labyrinth seal 16 with respect to the outside. Therefore, the labyrinth seal 16 prevents muddy water and foreign matter from entering the closed space S from the outside, and the arrival of the bearing seal 5 on the inside is reduced. Therefore, the bearing seal 5 only needs to have a simple configuration. For example, the bearing seal 5 may be composed of the two seal lips 22a and 22b as described above, and the combination of the seal lips 22a and 22b and the labyrinth seal 16 includes three sheets including the conventional side lip. It is possible to obtain a sealing function similar to that of a combination seal provided with a seal lip.

  Since the number of contacting lips is small in this way, the friction torque due to the bearing seal 5 can be reduced. Further, since the brake rotor 14 and the back plate 15 forming the closed space S are not in contact with each other and only face each other via the labyrinth seal 16, the friction torque does not increase. For these reasons, it is possible to reduce bearing rotational torque while ensuring sealing performance. The back plate 15 does not require severe rust prevention like the slinger in the combined bearing, and can be obtained at low cost by using an iron plate or the like. Therefore, it is possible to reduce the cost as compared with the case of providing a stainless slinger in the conventional combination seal.

  Further, since the brake rotor 14 is used as means for forming the labyrinth seal 16 and the closed space S, an increase in the number of parts can be avoided and an increase in cost can be avoided.

  Further, since the backup seal 20 is provided outside the bearing on the inboard side, the bearing seal 6 can be simple. Even if the bearing seal 6 having two seal lips 22a and 22b is used as described above, sufficient sealing performance can be obtained.

  FIG. 2 shows another embodiment of the present invention. This embodiment is an example applied to a wheel bearing device for supporting a driven wheel and rotating an inner ring. In the wheel bearing device 1, the hub wheel 10 does not have an inner diameter hole, and the end of the inboard side of the bearing outer ring mounting hole 9 a of the suspension device component 9 is covered with an end cap 24. Therefore, the bearing seal 6 on the inboard side in the example of FIG. 1 is omitted. The suspension device constituting member 9 is divided into a bearing housing portion 9A fitted with the outer ring 8 of the wheel bearing device 1 and a suspension device constituting member main body 9B, and the inner diameter portion of the back plate 15 is sandwiched between the divided surfaces. Installed.

  The brake rotor 14 is formed of a brake drum, and a circumferential groove 25 is formed on the end surface of the outer peripheral cylindrical portion 14b. The back plate 15 has a ring-shaped protrusion 26 that fits in the circumferential groove 25 of the brake rotor 14 with a gap, and the labyrinth seal 16 is interposed between the circumferential groove 25 and the ring-shaped protrusion 26. Is configured.

Also in this embodiment, since the closed space S and the labyrinth seal 16 are configured between the brake rotor 14 and the back plate 15, the bearing seal 5 on the outboard side has a simple configuration, and the sealing performance is ensured. However, the bearing rotational torque can be reduced. Further, since the end cap 24 is provided on the inboard side and the bearing seal is omitted, the torque is further reduced. As the bearing seal 5 on the outboard side, one having the two seal lips 22a and 22b described with reference to FIG.
Other configurations and effects in this embodiment are the same as those in the first embodiment, and the corresponding parts are denoted by the same reference numerals and description thereof is omitted.

  FIG. 3 shows still another embodiment of the present invention. This embodiment is an example applied to a wheel bearing device for supporting a driven wheel and rotating an outer ring, and is a second generation type. In the wheel bearing device 1, the outer member 2 is composed of only the bearing outer ring 8, and the bearing outer ring 8 has a wheel mounting flange 8 c on the outer periphery. A brake rotor 14 as a rotating member is attached to the flange 8c with a hub bolt 30. The brake rotor 14 is composed of a brake drum.

  The inner member 3 includes a bearing inner ring 11 and a shaft member 27 fitted to the inner diameter surface of the bearing inner ring 11. The shaft member 27 has a flange 27a on the outer periphery, and is fixed to a suspension device constituting member 28 such as a knuckle of the vehicle body by a bolt 29 at the flange 27a. Between the flange 27a of the shaft member 27 and the suspension member 28, the inner peripheral portion of the backput 15 is attached. A closed space S and a labyrinth seal 16 are provided between the brake rotor 14 and the back plate 15 as in the embodiment of FIG. However, in the case of this embodiment, in the closed space S, an end portion on the inboard side of the annular space RS between the outer member 2 and the inner member 3 faces. The inboard bearing seal 6 has the structure shown in FIG. 1B, that is, has two seal lips 22a and 22b. At the end of the outboard, the end of the outer member 2 is closed with an end cap 29, and thus the bearing seal is omitted.

In this embodiment, since the closed space S and the labyrinth seal 16 are configured between the brake rotor 14 and the back plate 15, the bearing seal 6 on the inboard side may have a simple configuration, while ensuring the sealing performance. The bearing rotational torque can be reduced. Further, since the end cap 29 is provided on the outboard side and the bearing seal is omitted, the torque is further reduced.
Other configurations and effects in this embodiment are the same as those in the first embodiment, and the corresponding parts are denoted by the same reference numerals and description thereof is omitted.

In the first embodiment shown in FIG. 1, the labyrinth seal 16 may be provided using the drum-type brake rotor 14 shown in FIG. 2, and in each embodiment shown in FIGS. The labyrinth seal 16 may be provided using a disc-type brake rotor 14 shown in FIG.
Further, the members constituting the labyrinth seal 16 and the closed space S are not limited to the brake rotor 14 and the labyrinth seal 16, and are fixed to a rotating body attached to the rotating side member of the outer member 2 and the inner member 3. Any stationary member attached to the side member may be used.
Furthermore, although the said embodiment demonstrated the case where it applied to the wheel bearing apparatus provided with the 1st generation type or the 2nd generation type wheel bearing, this invention can be applied regardless of a generation form, 3rd It can also be applied to generation and fourth generation type wheel bearing devices.

(A) is the fragmentary sectional view of the wheel bearing apparatus which concerns on 1st Embodiment of this invention, (B) is sectional drawing to which the I section of the same figure (A) was expanded. It is a fragmentary sectional view of the bearing device for wheels concerning other embodiments of this invention. It is a fragmentary sectional view of the bearing device for wheels concerning other embodiments of this invention. It is sectional drawing of a prior art example, and its partial expanded sectional view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Wheel bearing apparatus 2 ... Outer member 3 ... Inner member 4 ... Rolling element 5, 6 ... Bearing seal 14 ... Brake rotor (rotating member)
15 ... Back plate (stationary member)
16 ... Labyrinth seals 22a, 22b ... Seal lip S ... Closed space

Claims (4)

An outer member having a double-row raceway surface on the inner periphery, an inner member having a raceway surface facing the raceway surface on the outer periphery, a double-row rolling element interposed between the opposing raceway surfaces, and the outer In a wheel bearing device that includes a bearing seal that seals an end of an annular space between a member and an inward member, and supports the wheel rotatably with respect to the vehicle body,
The bearing seal between the outer member and the inner member is between a rotating body attached to the rotating member of the outer member and the inner member and a stationary member attached to the stationary member. A labyrinth seal is formed between the rotating body and the stationary member so as to form a closed space where the end of the annular space provided faces, the rotating body and the stationary member being in non-contact with each other, and serving as a path for opening the closed space to the outside. A wheel bearing device formed between the two.   The wheel bearing device according to claim 1, wherein the rotation-side member is a brake rotor, and the stationary member is a back plate provided to face the brake rotor.   3. The outer member according to claim 2, wherein the outer member is a fixed member, the inner member is a rotating member, and an outboard side end in an annular space between the outer member and the inner member is between the rotating member and the stationary member. A space between the inner periphery of the outer member and the outer periphery of the member attached to the inner member is located outside the bearing seal provided at the inboard side end of the annular space. Wheel bearing device provided with a backup seal for sealing. The wheel bearing device according to any one of claims 1 to 4, wherein the bearing seal facing the closed space between the rotating body and the stationary member is a contact seal having two seal lips.

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