JP2016017563A - Wheel support rolling bearing unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wheel support rolling bearing unit which hardly causes the come-off of a cap even if a bearing internal space is brought into a high-temperature state, and internal pressure is raised.SOLUTION: In a cap 17b which is pressure-inserted into an internal end opening part of an outer ring 19, a pressure-insertion part 28 of the opening part has a bottom plate part 29a which is bent from an end part of the inside of an axial direction (right hand in Fig.) at a substantially-right angle, the surface pressure of the pressure-insertion part 28 at an internal end side is raised by the rigidity of the bottom plate part 29a, and a fitting force of the cap 17b is improved. The pressure-insertion part 28 also has a circular part 29b which is bent from an end side of the pressure-insertion part at the outside of the axial direction (left hand in Fig.) at a substantially-right angle, the surface pressure of the pressure-insertion part 28 at an external end side is raised, and the fitting force of the cap 17b is improved. Furthermore, an inside-diameter side end part of the circular part 29b is made to approximate an external peripheral face of an inner ring 23, and a labyrinth part is formed.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an improvement of a wheel bearing rolling bearing unit for rotatably supporting wheels, particularly driven wheels (rear wheels of FF vehicles, front wheels of FR vehicles and RR vehicles) with respect to a suspension system of an automobile.

As a wheel bearing rolling bearing unit, for example, WO2003 / 071147 discloses a structure as shown in FIG.
In the case of this wheel support rolling bearing unit 2a, a hub 7a that is a rotating side race ring is provided on the inner diameter side of an outer ring 19 that is a stationary side race ring by a plurality of balls 14 and 14 each of which is a rolling element. It is supported rotatably. For this purpose, double-row outer ring raceways 10a and 10b, each of which is a stationary side raceway surface, are provided on the inner peripheral surface of the outer ring 19, and first and second outer race surfaces of the hub 7a are first and second rotary side raceway surfaces, respectively. Inner ring raceways 20 and 21 are provided. The hub 7 a is formed by combining the hub body 22 and the inner ring 23. Of these, the mounting flange 11a for supporting the wheel on the outer end portion of the outer peripheral surface of the hub main body 22, the first inner ring raceway 20 in the middle portion, and the first inner ring raceway portion in the middle portion. The small-diameter step portion 24 having a smaller diameter than the portion where the inner ring raceway 20 is formed is provided. Then, the inner ring 23 provided with the second inner ring raceway 21 having an arcuate cross section on the outer peripheral surface is externally fitted to the small diameter step portion 24. Further, the inner end surface of the inner ring 23 is held down by a caulking portion 25 formed by plastically deforming the inner end portion of the hub main body 22 radially outward, and the inner ring 23 is fixed to the hub main body 22. . Further, the inner end opening of the outer ring 19 is closed by a cap 17 a, and the space between the outer end inner peripheral surface of the outer ring 19 and the intermediate outer peripheral surface of the hub body 22 is closed by a seal ring 16 c. As a result, the space where the balls 14 and 14 are provided between the inner peripheral surface of the outer ring 19 and the outer peripheral surface of the hub 7a is blocked from the external space.
WO2003 / 071147

  Recently, a hub bearing having a caulking portion 25 as shown in FIG. 8 has become common. However, since the inner diameter portion of the caulking portion 25 becomes a space, the amount of air in the bearing increases, and the mounting flange When the brake rotor (not shown) attached to 11a reaches a high temperature, the heat is transmitted into the bearing through the attachment flange 11a, the bearing internal space becomes a high temperature state, the internal pressure increases, and the cap 17a may fall off. In particular, when the amount of air in the bearing internal space is large, even if the cap starts to be released, the internal pressure hardly decreases and may be released at once. Further, since the cap 17a of FIG. 8 has the collar portion in contact with the inner end surface of the outer ring, positioning is easy, but the effect of increasing the fitting surface pressure due to the rigidity of the bottom plate portion is small, so that the fitting force can be increased. difficult.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a wheel support rolling bearing unit in which a cap is unlikely to come off even when a bearing internal space is in a high temperature state and an internal pressure increases.

The stationary side race ring is an outer ring with a double row outer ring raceway on the inner peripheral surface, and the rotation side race ring is a hub with a double row inner ring raceway on the outer peripheral surface. Of which the mounting flange for supporting the wheel on the outer end of the outer peripheral surface of the hub body is the same, the first inner ring raceway is also in the middle, and the portion closer to the inner end of the middle Are provided with small diameter step portions that are smaller in diameter than the portion where the first inner ring raceway is formed, and the inner ring provided with the second inner ring raceway on the outer peripheral surface is fitted around the small diameter step portion. An inner end surface is suppressed by a caulking portion formed by plastically deforming the inner end portion of the hub body radially outwardly, and is provided between each outer ring raceway and the first and second inner ring raceways. The rolling element is a ball, and the entire inner end opening of the outer ring is closed by a cap. And it has the seal ring, in the wheel supporting rolling bearing unit which is provided between the outer end opening portion and the intermediate portion outer peripheral surface of the hub body of the outer ring,
A labyrinth portion is formed by bringing the outer portion of the cap in the axial direction close to the outer peripheral surface of the inner ring, or a lip provided on the outer portion of the cap in the axial direction is brought into sliding contact with the outer peripheral surface of the inner ring. Rolling bearing unit for wheel support.

  With the above-described configuration, even if the bearing internal space is in a high temperature state, the internal pressure increases, and the cap starts to come off, the pressure in the internal space on the cap side of the bearing internal space rapidly decreases due to the labyrinth portion and the lip. So the cap will not come off at once.

It is sectional drawing of the rolling bearing unit for wheel support which concerns on 1st Example of this invention. It is sectional drawing of the rolling bearing unit for wheel support which concerns on 2nd Example of this invention. It is sectional drawing of the rolling bearing unit for wheel support which concerns on the 3rd Example of this invention. It is sectional drawing of the rolling bearing unit for wheel support which concerns on the 4th Example of this invention. It is sectional drawing of the rolling bearing unit for wheel support which concerns on the 5th Example of this invention. It is sectional drawing of the rolling bearing unit for wheel support which concerns on the 6th Example of this invention. It is an enlarged view of the principal part of FIG. It is sectional drawing of the conventional rolling bearing unit for wheel support.

  Embodiments of a wheel bearing rolling bearing unit according to the present invention will be described below with reference to the drawings. The feature of the present invention is that the structure of the cap is devised, and the structure and operation of the other parts are the same as the conventional structure shown in FIG. The overlapping description will be omitted, and the structure and operation of the cap, which is a characteristic part of the present invention, will be described in detail below.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a sectional view showing a first embodiment of a wheel bearing rolling bearing unit according to the present invention.
The cap 17b press-fitted into the inner end opening of the outer ring 19 has a bottom plate portion 29a bent substantially at a right angle from the axially inner end (right side in the figure) of the press-fit portion 28. The rigidity of the bottom plate portion 29a The annular portion 29b is increased from the inner end side of the press-fit portion 28 to improve the fitting force of the cap 17b and is bent substantially at a right angle from the axially outer (left side) end side of the press-fit portion 28. The surface pressure on the outer end side of the press-fit portion 28 is increased, and the fitting force of the cap 17b is improved.
Further, the inner diameter side end portion of the annular ring portion 29b is brought close to the outer peripheral surface of the inner ring 23 to form a labyrinth portion. The purpose of this is to prevent the cap 17b from being pulled out at a stroke so that the pressure in the inner space inside the labyrinth portion suddenly drops if the cap is removed. In order to increase the decrease in the pressure described above, it is effective to reduce the volume of the internal space of the bearing unit on the axially inner side from the labyrinth portion, but in the present embodiment, the radial center portion of the bottom plate portion 29a is The volume is reduced by narrowing the caulking portion 25 to a shape that substantially conforms to the inner diameter side shape of the caulking portion 25.

  FIG. 2 is a sectional view showing a second embodiment of the wheel bearing rolling bearing unit according to the present invention. In the present embodiment, in order to further reduce the volume compared to the first embodiment, a portion of the cap 17c facing the vicinity of the inner end of the inner ring 23 in the axial direction is formed in an annular shape toward the inner ring 23. The aperture is close to and close to each other. The actions and effects are the same as in the first embodiment.

  FIG. 3 is a sectional view showing a third embodiment of the wheel bearing rolling bearing unit according to the present invention. The difference between the present embodiment and the first embodiment is that the outer ring surface 29c is bent obliquely from the axially outer side (left side in the figure) to the inner diameter side of the press-fitting portion 28 of the cap 17d. The labyrinth portion is formed between them, and the cylindrical member 26 having a shape substantially conforming to the inner diameter side shape of the caulking portion 25 is fixed to the cap 17d by welding or the like. The actions and effects are the same as in the first embodiment.

  FIG. 4 is a sectional view showing a fourth embodiment of the wheel bearing rolling bearing unit according to the present invention. The present embodiment has an annular portion 29d bent substantially perpendicularly from the end from the axially inner side (right side of the figure) of the press-fit portion 28 of the cap 17e, while the axial direction of the press-fit portion 28 of the cap 17e. An annular portion 29e is formed from the outer side (left side of the figure) toward the inner ring 23, and a cylindrical portion 29f along the outer peripheral surface of the inner ring 23 is formed from an inner diameter side end portion of the annular portion 29e. The portion 29f and the outer peripheral surface of the inner ring 23 form a labyrinth portion. Further, a cap 17e is formed so as to cover the end of the bearing unit from the axially inner side of the cylindrical portion 29f. According to this configuration, the amount of air in the internal space of the bearing unit can be further reduced and the labyrinth portion becomes longer compared to the above-described embodiments. Since the pressure drop time in the internal space can be made longer, the effect of stopping the end cap that has started to come out is enhanced.

  FIG. 5 is a sectional view showing a fifth embodiment of the wheel-supporting rolling bearing unit according to the present invention. The difference between the present embodiment and the first embodiment is that, in the outer ring 19, an annular groove 19a is provided in the press-fitted portion of the cap 17f, and a plurality of locking claws 27 provided in the cap 17f are engaged with the annular groove 19a. It has stopped. With this locking claw 27, the cap 17f can be prevented from coming off. Other operations and effects are the same as those of the first embodiment.

  FIG. 6 is a sectional view showing a sixth embodiment of the wheel bearing rolling bearing unit according to the present invention. FIG. 7 is an enlarged view of a main part of FIG. The difference between this embodiment and the first embodiment is that an annular portion 29d that is obliquely bent from the axially outer side (left side in the figure) to the inner diameter side of the press-fitting portion 28 with the outer ring 19 of the cap 17g is provided. A rubber or plastic lip 30 that is in sliding contact with the inner ring 23 is provided at the tip of the annular portion 29d. Since the bearing internal space becomes high temperature by heat conducted from the brake rotor to the mounting flange 11a, the temperature and internal pressure of the outer side in the axial direction of the lip 30 are likely to be higher than the inner side. In the case of the present embodiment, when the pressure in the outer space in the axial direction of the lip 30 is increased, the force for pulling out the cap 17g is applied only to the annular portion 29d and the lip 30, so the pressure receiving area is smaller than those of the first to fifth embodiments. Since the cap detachment force itself is small, the cap detachment is less likely to occur than in the first to fifth embodiments. In the unlikely event that a slip occurs, the pressure reduction in the axially inner space of the lip 30 is maintained by the lip 30, and the pressure receiving area in the case of a negative pressure is the entire bottom plate portion 31 of the cap 17g. The deterrence of omission is increased and omission is further suppressed.

2a Bearing unit 7a Hub 10a, 10b Outer ring raceway 11a Mounting flange 14 Ball 16c Seal ring 17a, 17b, 17c, 17d, 17e, 17f, 17g Cap 18 Annular groove 20, 21 Inner ring raceway 22 Hub body 23 Inner ring 24 Small diameter step 25 Caulking part 26 Member 27 Locking claw 28 Press-fit part 29a Bottom plate part 29b, 29c, 29d, 29e Annulus part 29f Cylindrical part 30 Lip

Claims (1)

The stationary side race ring is an outer ring provided with a double row outer ring raceway on the inner peripheral surface, and the rotation side race ring is a hub provided with a double row inner ring raceway on the outer peripheral surface. The mounting flange for supporting the wheel on the outer end portion of the outer peripheral surface of the hub body, the first inner ring raceway in the middle portion, and the portion closer to the inner end of the middle portion A small-diameter step portion that is smaller in diameter than the portion that formed the first inner ring raceway is provided, and the inner end surface of the inner ring that is externally fitted to the small-diameter step portion and that is provided with the second inner ring raceway on the outer peripheral surface. Is restrained by a caulking portion formed by plastically deforming the inner end portion of the hub body radially outward, and provided between each outer ring raceway and the first and second inner ring raceways. The rolling element is a ball, and the entire inner end opening of the outer ring is closed by a cap. , Seal ring, in the wheel supporting rolling bearing unit which is provided between the intermediate portion outer peripheral surface of the hub body and an outer end opening of the outer ring,
A labyrinth portion is formed by bringing the outer portion of the cap in the axial direction close to the outer peripheral surface of the inner ring, or a lip provided on the outer portion of the cap in the axial direction is brought into sliding contact with the outer peripheral surface of the inner ring. Rolling bearing unit for wheel support.

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