JP2018204699A - Hub unit bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a structure of a hub unit bearing capable of preventing indentation from being formed on an outer ring track and an inner ring track without promoting destabilization of vehicle behavior. SOLUTION: A hub 3a has a rotary flange 8a having a disk-shaped solid portion 27 and a flange portion 38 protruding radially outward from the outer peripheral portion of the solid portion 27, and the rotary flange 8. A hollow tubular shaft portion 25 that protrudes inward in the axial direction from the inner side surface in the axial direction and has a double-row inner ring tracks 7a and 7b on the outer peripheral surface is provided. Further, the hub 3a suppresses the stress wave generated by the rotating flange 8a from being transmitted to the axial intermediate portion of the shaft portion 25 to the portion located axially outside the inner ring track 7a on the outer side in the axial direction. It has a stress wave suppression part. [Selection diagram] Fig. 1

Description

  The present invention relates to a hub unit bearing for rotatably supporting a wheel of an automobile with respect to a suspension device.

  An automobile wheel and a braking rotator are supported by a hub unit bearing so as to be rotatable with respect to the suspension device. The hub unit bearing includes an outer member having a double row outer ring raceway on an inner peripheral surface, an inner member having a double row inner ring raceway on the outer peripheral surface, the double row outer ring raceway, and the double row inner ring raceway. In between, a plurality of rolling elements are provided so as to be freely rollable for each row. The outer member is coupled and fixed to the suspension device and does not rotate during use. The inner member has a rotating flange for supporting the wheel and the brake rotating body.

  By the way, if the impact load is applied to the rotating flange while the vehicle is running, such as when the wheel contacts the curb, indentations may be formed on the outer ring track and the inner ring track based on the impact load. Such indentations are particularly likely to be formed on the outer ring raceway and the inner ring raceway on the axially outer side close to the rotating flange. Further, in a vehicle equipped with a tire with a low flatness that has begun to spread in recent years, an impact load is likely to be applied to the rotating flange because the rim portion of the wheel, instead of the tire, directly collides with the curb.

  On the other hand, JP 2014-134234 A discloses a hub unit bearing having a structure for preventing formation of indentations on the outer ring raceway and the inner ring raceway. FIG. 5 shows the structure of the hub unit bearing 1 described in Japanese Patent Application Laid-Open No. 2014-134234. The hub unit bearing 1 includes an outer ring 2 that is an outer member, a hub 3 that is an inner member, and a plurality of rolling elements 4.

  The outer ring 2 includes double row outer ring raceways 5a and 5b provided on the inner peripheral surface, and a stationary flange 6 for supporting and fixing the outer ring 2 to the knuckle 12 of the suspension device. The hub 3 is disposed coaxially with the outer ring 2 on the inner diameter side of the outer ring 2, and has a double-row inner ring raceway 7 a, 7 b provided on a portion of the outer peripheral surface facing the double-row outer ring raceway 5 a, 5 b. And a rotating flange 8 for supporting a wheel and a braking rotator (not shown). A plurality of rolling elements 4 are rotatably arranged between the outer ring raceways 5a and 5b in the double row and the inner ring raceways 7a and 7b in the double row for each row. With such a configuration, the hub 3 is rotatably supported on the inner diameter side of the outer ring 2.

  The rotating flange 8 is configured in an annular shape in the illustrated example, and has a radially outer thin portion 13, a radially inner thick portion 14, an axial inner surface of the thin portion 13, and an axial direction of the thick portion 14. And a step portion 15 connecting the inner surface. With such a configuration, the hub 3 is reduced in weight while ensuring the rigidity of the rotating flange 8.

  The hub 3 includes a hub body 10 having a small diameter cylindrical portion 9 at an inner end in the axial direction, and an inner ring 11 press-fitted into the small diameter cylindrical portion 9. Note that “inside” in the axial direction refers to the right side of FIGS. 1 to 5, which is the center side in the width direction of the vehicle when the hub unit bearing 1 is assembled to an automobile. On the other hand, the left side of FIGS. 1 to 5, which is the outer side in the width direction of the vehicle in a state where the hub unit bearing 1 is assembled to an automobile, is referred to as “outside” in the axial direction.

  In the example shown in the drawing, at the outer end in the axial direction of the outer ring 2 and at the portion located vertically downward (downward in FIG. 5) when the hub unit bearing 1 is assembled to the vehicle, radially outward. A protruding protrusion 16 is provided. An abutting surface 17 is provided on the outer end surface in the axial direction of the radially outer end portion of the protrusion 16, and the abutting surface 17 is in close proximity to the inner side surface in the axial direction of the rotary flange 8.

  While the vehicle is running, the wheel is in contact with the curb, so that an axial impact load is applied to the rotary flange 8 and the vertical lower portion of the rotary flange 8 is deformed so as to fall inward in the axial direction. Then, the inner surface in the axial direction of the rotating flange 8 contacts the abutting surface 17. For this reason, a part of the impact load is transmitted to the outer ring 2 supported and fixed to the suspension device. As a result, the impact load applied to the rolling contact portion between the outer ring raceways 5a and 5b and the inner ring raceways 7a and 7b and the rolling elements 4 can be reduced, and indentations are hardly formed on the outer ring raceways 5a and 5b and the inner ring raceways 7a and 7b. It has become.

  As another related technique, Japanese Patent Application Laid-Open No. 2015-85812 discloses that a shaft is provided with a deformation-permissible space in the stationary flange of the outer ring, and the rigidity against the vertical displacement of the outer ring body based on the impact load is reduced. A technique for preventing indentation from being formed on the outer ring raceway on the inner side in the direction is disclosed. Japanese Patent Laid-Open No. 2013-136068 discloses that the hub body constituting the hub has a cylindrical core material made of a low melting point metal and an iron-based alloy, and covers an outer portion excluding the end of the core material. A technique is disclosed in which a forging process is performed on a material constituted by a bottom cylindrical surface layer material, and then the low melting point metal constituting the core material is melted and removed.

JP 2014-134234 A Japanese Patent Laying-Open No. 2015-85812 JP2013-136068A

  The structure shown in FIG. 5 has room for improvement from the following aspects. That is, when an impact load is applied so that the inner surface in the axial direction of the rotating flange 8 comes into contact with the abutting surface 17 due to the wheel contacting the curb or the like, the behavior of the vehicle may be unstable. There is sex. In this state, when the inner surface in the axial direction of the rotating flange 8 and the abutting surface 17 are in contact with each other, only the rotation of the wheel is not smooth, and only one of the four wheels is temporarily braked. Therefore, instability of vehicle behavior is easily promoted.

  Further, the outer ring raceways 5a and 5b and the inner ring raceway 7a are prevented between the axially inner side surface of the rotary flange 8 and the abutting surface 17 while preventing contact in a normal state where no impact load is applied to the rotary flange 8. In order to prevent formation of indentations in 7b, it is necessary to strictly regulate the gap. For this reason, the manufacturing cost of the hub unit bearing 1 may increase.

  Further, in order to avoid interference between the coupling member such as a hub bolt or stud for supporting and fixing the wheel to the rotating flange 8 and the projection 16, the circumscribed circle diameter of the projection 16 centered on the central axis of the hub 3 is set. It is necessary to make it smaller than the inscribed circle diameter of the head of the coupling member.

  Further, in order to prevent interference between the axially outer surface of the radially inner portion of the protrusion 16 and the axially inner surface of the rotary flange 8, the step portion 15 has a diameter compared to a structure in which the protrusion 16 is not provided. It must be located inward. As a result, the rigidity of the rotating flange 8 is reduced as compared with a structure in which the protrusion 16 is not provided.

  Further, if the portion that contacts the abutting surface 17 is a discontinuous surface having a thinned portion or the like, the circumferential side surface of the protrusion 16 may abut against the discontinuous portion, and the wheel may be locked. Of the eight axially inner surfaces, the portion that contacts the abutting surface 17 needs to be a flat surface that is continuous over the entire circumference. Therefore, in the structure in which the rotary flange 8 is configured by a plurality of radially arranged arm portions, the proportion of the portion that is present between the arm portions and that has a smaller thickness than the arm portions or the thinned portion is present. There is a possibility that the weight of the hub 3 increases as the size decreases.

  In view of the circumstances as described above, the present invention realizes a hub unit bearing structure capable of preventing formation of indentations on an outer ring raceway and an inner ring raceway without promoting destabilization of vehicle behavior. It is an object.

The hub unit bearing of the present invention includes an outer member, an inner member, and a rolling element.
The outer member has a double row outer ring raceway on an inner peripheral surface.
The inner member has double-row inner ring raceways on the outer peripheral surface.
A plurality of rolling elements are arranged between the outer row raceway in the double row and the inner raceway in the double row so as to roll freely for each row.
The inner member includes a disk-shaped solid portion, a rotating flange having a flange portion protruding radially outward from an outer peripheral portion of the solid portion, and an axial direction from an axial inner surface of the rotating flange. A hollow cylindrical shaft portion projecting inward and having the double-row inner ring raceway on the outer circumferential surface. Further, the inner member is configured such that stress waves generated by the rotating flange are axially intermediate in the shaft portion in a portion of the double-row inner ring raceway that is located on the axially outer side of the inner ring raceway on the axially outer side. A stress wave suppression unit for suppressing transmission to the unit.

  In the present invention, the shaft portion is present in a portion located between the solid portion and the inner ring raceway on the outer side in the axial direction with respect to the axial direction, and on the inner side in the axial direction than the thin tube portion. And a thick-walled cylinder portion having a radial thickness greater than the radial thickness of the thin-walled cylinder portion.

  Alternatively or additionally, the inner member may be a first member having a solid portion and a reinforced portion constituting an axially outer portion of the flange portion, and an axially inner side of the flange portion. The reinforcing part constituting the part and the second member having the shaft part can be configured by being coupled and fixed in the axial direction.

  In the present invention, a restraining member separate from the inner member can be supported on the rotating flange. Specifically, for example, the restraining member is supported with respect to the rotating flange by a stud, a hub bolt, or the like for supporting and fixing a wheel to the rotating flange. In addition, as long as the said suppression member can suppress the said stress wave, the material and shape in particular will not be restrict | limited, but the said suppression member can be comprised, for example with an annular | circular shaped metal plate.

  In the case of providing the restraining member, the restraining member is placed in close proximity to a part of the outer member or a member fixed to the outer member, and an impact load applied to the rotating flange is applied to the outer ring raceway and the inner ring. It is possible to provide a bypass member that bypasses the outer member without passing through a track or the rolling element. In this case, if the bearing is supported with respect to the outer member and the bypass member is closely opposed to the bearing, an increase in rotational resistance of the rotating flange is suppressed even when the bearing and the bypass member are in contact with each other. This is preferable. It is more preferable to use a rolling bearing as the bearing because the stress wave can be absorbed in the bearing. However, a sliding bearing can also be used as the bearing.

  According to the hub unit bearing of the present invention, a structure capable of preventing the formation of indentations on the outer ring raceway and the inner ring raceway can be realized without promoting instability of vehicle behavior.

FIG. 1 is a sectional view showing a hub unit bearing of a first example of an embodiment of the present invention. FIG. 2 is a cross-sectional view for explaining an example of a manufacturing method of a hub main body constituting the hub unit bearing of the first example of the embodiment of the present invention. FIG. 3 is a sectional view showing a hub unit bearing of a second example of the embodiment of the present invention. FIG. 4 is a sectional view showing a hub unit bearing of a third example of the embodiment of the present invention. FIG. 5 is a cross-sectional view showing an example of a conventional structure of a hub unit bearing.

[First example of embodiment]
FIG. 1 shows a first example of an embodiment of the present invention. The hub unit bearing 1a of this example includes an outer ring 2a that is an outer member, a hub 3a that is an inner member, and a plurality of rolling elements 4, as in the conventional structure shown in FIG.

  The outer ring 2a is made of a hard metal such as medium carbon steel, and includes double-row outer ring raceways 5a and 5b and a stationary flange 6 for supporting and fixing the outer ring 2a to the suspension device. The double row outer ring raceways 5a and 5b are provided on the inner peripheral surface of the outer ring 2a. The stationary flange 6 is provided at the axially intermediate portion of the outer ring 2a so as to protrude radially outward. Support holes 18 are respectively provided at a plurality of locations in the circumferential direction of the radial intermediate portion of the stationary flange 6. The outer ring 2a is supported and fixed to a knuckle constituting the suspension device by a coupling member such as a bolt screwed or inserted into each of the support holes 18.

  The hub 3a is disposed coaxially with the outer ring 2a on the inner diameter side of the outer ring 2a. The double row inner ring raceways 7a and 7b are provided on the outer peripheral surface of the hub 3a at a portion facing the double row outer ring raceways 5a and 5b. Such a hub 3a is configured by combining a hub body 10a made of hard metal such as medium carbon steel and an inner ring 11 made of hard metal such as bearing steel.

  A cylindrical small-diameter cylindrical portion 9a is provided on the inner side in the axial direction of the hub body 10a. The inner ring 11 is externally fitted to the small-diameter cylindrical portion 9a, and a portion of the small-diameter cylindrical portion 9a that protrudes inward in the axial direction from the axial inner end surface of the inner ring 11 is plastically deformed radially outward. The inner end surface in the axial direction is pressed down by the formed caulking portion 21. With such a configuration, the hub body 10a and the inner ring 11 are coupled and fixed.

  Of the double-row inner ring raceways 7a, 7b, the inner ring raceway 7a on the outer side in the axial direction is provided on the outer peripheral surface of the axially intermediate portion of the hub body 10a, and the inner ring raceway 7b on the inner side in the axial direction It is provided on the outer peripheral surface.

  In this example, the hub 3a has a single plate-like rotating flange 8a, and protrudes inward in the axial direction from the axial inner surface of the rotating flange 8a, and has double-row inner ring raceways 7a and 7b on the outer peripheral surface. A hollow cylindrical shaft portion 25 and a cylindrical pilot portion 26 protruding outward in the axial direction from the axially outer surface of the rotary flange 8a are provided.

  The rotating flange 8 a includes a disk-shaped solid portion 27 and a flange portion 38 that protrudes radially outward from the outer peripheral portion of the solid portion 27. The flange portion 38 includes a radially outer thin portion 13 and a radially inner thick portion 14. The axial inner side surface of the thin portion 13 and the axial inner side surface of the thick portion 14 are: They are connected by a step 15. Attachment holes 19 are respectively provided at a plurality of locations in the circumferential direction of the radially intermediate portion of the thin portion 13. The wheel and the brake rotating body are supported on the flange portion 38 by a stud 20 press-fitted into each of the mounting holes 19 or a hub bolt screwed.

  In this example, the axially outer side surface of the rotating flange 8a is a flat surface orthogonal to the central axis of the hub 3a. That is, the axially outer surface of the solid portion 27 and the axially outer surface of the flange portion 38 exist on the same plane orthogonal to the central axis of the hub 3a. In addition, the axial thickness of the solid portion 27 is thinner than the axial thickness of the thick portion 14 constituting the flange portion 38 and is the same as the axial thickness of the thin portion 13. That is, the inner side surface in the axial direction of the thick portion 14 is positioned on the inner side in the axial direction from the inner side surface in the axial direction of the solid portion 27, and the inner side surface in the axial direction of the thin portion 13 The side surface exists on the same plane orthogonal to the central axis of the hub 3a. With such a structure, the rigidity of the flange portion 38 in the axial direction is increased.

  In the present example, the flange portion 38 is formed in an annular shape that is continuous over the entire circumference. However, the flange part can also be comprised from the several flange piece provided so that it might extend radially from the outer peripheral part of a solid part.

  The shaft portion 25 has a thin cylindrical portion 29 present at the axially outer end portion, and a radial thickness that is present on the axially inner side of the thin cylindrical portion 29 and is thicker than the radial thickness of the thin cylindrical portion 29. And a thick cylindrical portion 30 having a thickness. The double-row inner ring raceways 7 a and 7 b are provided over the entire circumference at two positions in the axial direction of the outer peripheral surface of the thick-walled cylindrical portion 30.

  The thin cylindrical portion 29 exists in the axially outer end portion of the shaft portion 25, that is, in a portion located between the solid portion 27 and the inner ring raceway 7 a outside in the axial direction with respect to the axial direction. In short, the thin-walled cylindrical portion 29 exists in a portion of the shaft portion 25 that is out of the axial direction outside the inner ring raceway 7a. In the illustrated example, the thin cylindrical portion 29 is provided in a portion adjacent to the inside in the axial direction of the solid portion 27 and has an inner peripheral surface that is a curved surface having a substantially arcuate cross section. The radial thickness of the thinnest cylindrical portion 29 having the smallest radial thickness is about 1/4 to 1/2 of the radial thickness of the axially outer end of the thick cylindrical portion 30, preferably It is about 1/3 to 1/2. A seal lip constituting the seal ring 23 is in sliding contact with the outer peripheral surface of the thin-walled cylinder portion 29 over the entire periphery.

  In this example, the inner peripheral surface of the thick-walled cylindrical portion 30 is a conical surface that is inclined in a direction in which the inner diameter becomes smaller toward the inner side in the axial direction.

  The inner end portion in the axial direction of the thin tube portion 29 and the outer end portion in the axial direction of the thick tube portion 30 are connected by a connecting tube portion 31 having a substantially trapezoidal cross section. That is, the connection cylinder part 31 is comprised including the groove shoulder part of the inner ring raceway 7a of the axial direction outer side. The inner peripheral surface of the connecting cylinder portion 31 is inclined in a direction in which the inner diameter becomes smaller toward the inner side in the axial direction, and the inclination angle with respect to the central axis of the hub 3a is larger than the inclination angle of the inner peripheral surface of the thick tube portion 30. There is also a big conical surface.

  In other words, the shaft portion 25 has a recess 28 that is open on the inner surface in the axial direction and whose inner peripheral surface has a substantially triangular flask shape. When the axially inner side surface of the solid portion 27, which is a flat surface perpendicular to the central axis of the hub 3a, is used as a substantially triangular flask-shaped bottom surface, a thin cylinder is formed around a portion corresponding to the bottom of the substantially triangular flask shape. The portion 29 is a connection tube portion 31 around the portion corresponding to the substantially conical flask-shaped conical body portion, and the thick tube portion 30 is the portion corresponding to the substantially triangular flask-shaped neck portion. However, the connecting cylinder portion 31 may be omitted, and the inner end portion in the axial direction of the thin tube portion 29 and the outer end portion in the axial direction of the thick tube portion 30 may be connected by a stepped portion.

  The pilot portion 26 has an outer peripheral surface that is a cylindrical surface. The pilot part 26 is a part for externally fitting the wheel and the braking rotator to position the wheel and the braking rotator in the radial direction when the hub unit bearing 1a is used. In the illustrated example, the inner diameter side of the cylindrical pilot portion 26 has a hollow structure, but a plurality of reinforcing ribs are provided between the inner peripheral surface of the pilot portion 26 and the outer surface in the axial direction of the solid portion 27. The rigidity of the flange portion 38 in the axial direction can be further improved by providing it so as to extend.

  The rolling elements 4 are made of hard metal such as bearing steel or ceramic, and a plurality of rolling elements 4 are provided for each row between the double row outer ring raceways 5a and 5b and the double row inner ring raceways 7a and 7b. It is arranged to roll freely. In the illustrated example, balls are used as the rolling elements 4, but tapered rollers can also be used.

  In this example, the axially outer opening of the cylindrical inner space 22 existing between the inner peripheral surface of the outer ring 2 a and the outer peripheral surface of the hub 3 a is closed by the seal ring 23. On the other hand, the axially inner opening of the internal space 22 is closed by a bottomed cylindrical cover 24 that is fitted and fixed to the axially inner end of the outer ring 2a. However, the axially inner opening of the internal space can be closed by a combination seal ring configured by combining a seal ring and a slinger.

  An example of the manufacturing method of the hub body 10a will be described with reference to FIG. When manufacturing the hub body 10a, first, as shown in FIG. 2, an intermediate material 32 having a substantially π-shaped cross section having a recess 28z that is open on the inner surface in the axial direction and whose inner peripheral surface is cylindrical. make. The intermediate material 32 is manufactured by plastically deforming a metal material as a material by forging. A thin cylindrical portion 29z that becomes the thin cylindrical portion 29 in the completed state is provided in the intermediate portion in the axial direction of the intermediate material 32, and a portion existing on the inner side in the axial direction from the thin cylindrical portion 29z is in the completed state. A thick tube portion 30z that becomes the thick tube portion 30 is provided. The outer diameter of the thick cylindrical portion 30z is larger than the outer diameter of the thin cylindrical portion 29z. Furthermore, a small-diameter cylindrical portion 9z that becomes a small-diameter cylindrical portion 9a in a completed state is provided at the axially inner end portion of the intermediate material 32. The hub main body 10a can be manufactured by reducing the diameter of the inner portion of the intermediate material 32 in the axial direction and performing necessary processing such as cutting and grinding.

  Alternatively, the hub body 10a is made of a low-melting-point metal columnar core material and an iron-based alloy, as in the technique described in Japanese Patent Application Laid-Open No. 2013-136068, and an outer portion excluding an end portion of the core material. It can also be made by forging a material composed of a covered bottomed cylindrical surface layer material and then melting and removing the low melting point metal constituting the core material.

  According to the hub unit bearing 1a of this example, the structure that can prevent the formation of indentations on the outer ring raceways 5a and 5b and the inner ring raceways 7a and 7b can be achieved without promoting destabilization of the behavior of the vehicle. Can be realized.

  That is, as shown by the arrow α in FIG. 1, the flange portion 38 passes through the wheel supported by the rotating flange 8 a by, for example, the wheel contacting the curb while the vehicle on which the hub unit bearing 1 a is mounted. When an impact load is applied from below to above, this impact load is supported by a rotating flange 8a configured in a single plate shape. Further, when an impact load is applied to the flange portion 38, a stress wave is generated in the rotating flange 8a due to the influence of inertia. This stress wave propagates from the rotary flange 8 a to the shaft portion 25. The stress wave propagates through the hub body 10a at a propagation speed determined according to the physical properties of the metal material constituting the hub body 10a. Further, since the stress wave is a wave, a part of the stress wave is reflected at the boundary surface between different media, and the rest is transmitted.

  In this example, since the thin cylindrical portion 29 is provided at the axially outer end portion of the shaft portion 25 adjacent to the inside of the solid portion 27 in the axial direction, the light propagates from the rotary flange 8a to the shaft portion 25. The stress wave is repeatedly reflected on the inner peripheral surface and the outer peripheral surface of the thin cylindrical portion 29 as indicated by an arrow β in FIG. As a result, the phases of the waves constituting the stress wave are shifted, the peaks of the stress waves propagating to the double row inner ring raceways 7a, 7b provided on the outer peripheral surface of the hub body 10a are averaged and reduced, and the inner ring raceway 7a is reduced. , 7b and the outer ring raceways 5a and 5b, and the impact load applied to the rolling contact portion between the rolling elements 4 is reduced. As a result, indentations are prevented from being formed on the inner ring raceways 7a and 7b and the outer ring raceways 5a and 5b, in particular, the inner ring raceway 7a and the outer ring raceway 5a on the outer side in the axial direction. That is, in this example, the thin cylindrical portion 29 functions as a stress wave suppressing portion for suppressing the stress wave generated in the rotating flange 8a from being transmitted to the axial intermediate portion of the shaft portion 25.

  On the other hand, in the conventional structure shown in FIG. 5, the radial thickness of the portion of the hub body 10 existing between the rotating flange 8 and the inner ring raceway 7a outside in the axial direction in the axial direction is the hub body 10. Of these, it is thicker than the radial thickness of the portion existing on the inner diameter side of the inner ring raceway 7a on the outer side in the axial direction. For this reason, when an impact load is applied to the rotary flange 8 through the wheel and a stress wave is generated in the rotary flange 8, the stress wave is directly or with a small number of reflections as shown by the arrow γ in FIG. There is a possibility of being propagated to 7a and 7b. As a result, a large impact load is applied to the rolling contact portion between the inner ring raceways 7a and 7b and the outer ring raceways 5a and 5b and the rolling elements 4, and indentations may be formed on the inner ring raceways 7a and 7b and the outer ring raceways 5a and 5b. There is.

  In this example, a structure that can prevent the formation of indentations on the inner ring raceways 7a and 7b and the outer ring raceways 5a and 5b is rotated when an impact load is applied to the rotary flange 8, as in the conventional structure of FIG. This can be realized without providing the abutment surface 17 that contacts the inner surface in the axial direction of the flange 8. Therefore, even when an impact load is applied to the rotary flange 8a, the instability of the behavior of the vehicle is not promoted. In addition, unlike the conventional structure of FIG. 5, it is not necessary to strictly regulate the gap between the axial inner surface of the rotary flange 8 and the abutting surface 17, so that the manufacturing cost of the hub unit bearing 1a can be reduced. It can be prevented from increasing. Further, it is possible to prevent the rigidity of the rotary flange 8 from being lowered and the weight of the hub 3 from being increased as in the conventional structure of FIG.

  In addition, this invention can also be implemented in combination with the technique as described in Unexamined-Japanese-Patent No. 2015-85812. In other words, if a deformation-allowing space is provided in the stationary flange and the rigidity against the vertical displacement of the outer ring main body due to impact load is lowered, indentations are formed on the outer ring raceway and the inner ring raceway, particularly on the outer ring raceway in the axial direction. This can be prevented more effectively.

[Second Example of Embodiment]
FIG. 3 shows a second example of the embodiment of the present invention. The hub 3b constituting the hub unit bearing 1c of the present example is configured by coupling and fixing an axially outer first member 39 and an axially inner second member 40 in the axial direction.

  The first member 39 includes a solid portion 27, a reinforced portion 41 that protrudes radially outward from the outer peripheral portion of the solid portion 27, and that constitutes an axially outer side portion of the flange portion 38a, and a pilot portion. 26, and has a fitting recess 42 on the inner side surface in the axial direction. The bottom surface of the fitting recess 42 is a flat surface orthogonal to the central axis of the hub 3b. Moreover, the 1st through-hole 43 is each provided in the circumferential direction several places of the radial direction intermediate part of the to-be-reinforced part 41. As shown in FIG. In the case of this example as well, the axial direction of the flange portion 38 is provided by providing a plurality of reinforcing ribs between the inner peripheral surface of the pilot portion 26 and the axially outer side surface of the solid portion 27. It is possible to further improve the rigidity.

  The second member 40 is provided so as to be bent radially outward from the axially outer end portion of the hollow cylindrical shaft portion 25 and the axial portion 25, and constitutes the axially inner portion of the flange portion 38a. And a reinforcing portion 44 to be used. That is, the reinforcing portion 44 has a hollow structure in which the metal material constituting the second member 40 does not exist on the inner diameter side. In addition, second through holes 45 are respectively provided at a plurality of locations in the circumferential direction of the intermediate portion in the radial direction of the reinforcing portion 44. In this example, the second member 40 has a substantially π-shaped cross section, has a small-diameter cylindrical portion 9a on the inner side in the axial direction, and a main body portion 46 having an inner ring raceway 7a on the outer side in the axial direction. The inner ring 11 has an inner ring raceway 7b that is axially inner on the outer peripheral surface.

  The first member 39 and the second member 40 are aligned with each other by fitting the outer circumferential surface of the outer side in the axial direction of the reinforcing portion 44 into the fitting recess 42, and the first member 39 and the second member 40 are arranged on the bottom surface of the fitting recess 42. The stud 20 is press-fitted from the inner side in the axial direction into the first through hole 43 and the second through hole 45 in a state where the outer surface in the axial direction of the second member 40 is abutted and fixed in the axial direction. .

  In this example, the flange part 38a which comprises the rotation flange 8b is comprised by combining the to-be-reinforced part 41 of an axial direction outer side, and the reinforcement part 44 of an axial direction inner side. And since the to-be-reinforced part 41 is a solid structure in which the solid part 27 exists in the inner diameter side, the rigidity regarding an axial direction and radial direction is high. On the other hand, the reinforcing portion 44 has a hollow structure in which the metal material constituting the second member 40 does not exist on the inner diameter side, so that the rigidity in the axial direction and the radial direction is lower than that of the reinforced portion 41. . Therefore, when an impact load is applied to the flange portion 38a as shown by an arrow α in FIG. 3 while the vehicle equipped with the hub unit bearing 1c of this example is traveling, most of the impact load is applied to the reinforcing portion 44. Thus, the impact load applied to the reinforced portion 41 is reduced. As a result, the stress wave generated in the reinforcing portion 44 constituting the second member 40 can be reduced, and the peak of the stress wave propagated to the shaft portion 25 can be reduced.

  Further, since the rigidity of the reinforced portion 41 and the rigidity of the reinforced portion 44 are different, the elastic deformation amount of the reinforced portion 41 and the elastic deformation amount of the reinforced portion 44 due to the input of the impact load in the axial direction and the radial direction are reduced. There is a difference. Then, minute vibrations are generated at the contact portion between the axially inner side surface of the reinforced portion 41 and the axially outer side surface of the reinforcing portion 44, and frictional heat is generated. Therefore, when the stress wave generated in the reinforced portion 41 of the rotating flange 8b is transmitted to the reinforced portion 44, it is attenuated as indicated by arrows β1 → β2 in FIG. The peak of the propagated stress wave can be further reduced. As described above, in this example, the rotation flange 8b is configured by combining the solid structure to-be-reinforced portion 41 in which the solid portion 27 exists on the inner diameter side and the hollow structure reinforcement portion 44, thereby rotating the rotation flange 8b. The stress wave suppression part for suppressing that the stress wave which generate | occur | produced in the flange 8b is transmitted to the axial direction intermediate part of the axial part 25 is comprised.

  In this example, the hub 3b is configured by combining a first member 39 having a solid portion 27 and a second member 40 having a hollow structure. Since each of the first member 39 and the second member 40 does not have a complicated shape like the hub body 10a of the first example of the embodiment, it can be easily manufactured by forging. The structure and operational effects of the other parts are the same as in the first example of the embodiment.

[Third example of embodiment]
FIG. 4 shows a third example of the embodiment of the present invention. In the hub unit bearing 1b of this example, the bearing 33 is fitted and fixed to the outer end portion in the axial direction of the outer ring 2b. In this example, a ball bearing in which both end portions in the axial direction of the internal space are sealed with seal rings is used as the bearing 33. However, as the bearing 33, various rolling bearings such as a cylindrical roller bearing or a sliding bearing can be used. By such a bearing 33, moisture adhering to the outer peripheral surface of the outer ring 2b travels along the outer peripheral surface of the outer ring 2b and reaches the gap between the axial outer end surface of the outer ring 2b and the axial inner surface of the rotary flange 8a. Is prevented. That is, the bearing 33 functions as a dam portion for damming moisture.

  In this example, a bypass ring 34, which is a bypass member, is supported and fixed on the inner surface in the axial direction of the rotary flange 8a. The bypass ring 34 is formed in an annular shape with an L-shaped cross section by bending a metal plate, and is a cylindrical portion 35 and a bent portion that is bent radially outward from the axial outer end portion of the cylindrical portion 35. 36. The inner peripheral surface of the cylindrical portion 35 is in close proximity to the outer peripheral surface of the outer ring constituting the bearing 33. Through holes 37 are respectively provided at a plurality of locations in the circumferential direction of the bent portion 36. In this example, the shaft ring of the stud 20 inserted through each of the through holes 37 of the bent portion 36 is further press-fitted into the mounting hole 19 of the rotating flange 8a, whereby the bypass ring 34 is supported with respect to the rotating flange 8a. Yes.

  In this example, the bypass ring 34 is provided separately from the rotary flange 8 a and is supported and fixed to the rotary flange 8 a by the stud 20. For this reason, when an impact load in the axial direction is applied to the rotating flange 8a due to the wheels coming into contact with the curb while the vehicle equipped with the hub unit bearing 1b is traveling, a part of the impact load is duplicated. The outer ring raceway 5a, 5b in the row, the inner ring raceways 7a, 7b in the double row, and the rolling element 4 can be bypassed to the outer ring 2b. Specifically, when an axial impact load is applied to the rotary flange 8a, if the vertical lower side portion of the rotary flange 8a is deformed so as to fall inward in the axial direction, the cylindrical portion 35 of the bypass ring 34 is obtained. And the outer peripheral surface of the outer ring of the bearing 33 are in contact with each other. As a result, a part of the impact load is transmitted to the outer ring 2b supported and fixed to the suspension device via the bearing 33, so that the inner ring raceways 7a and 7b and the outer ring raceways 5a and 5b and the rolling element 4 roll. The impact load applied to the contact portion can be reduced.

  In this example, when an impact load is applied to the rotating flange 8a, the portion that the inner peripheral surface of the cylindrical portion 35 contacts is the outer peripheral surface of the outer ring of the bearing 33 that can rotate with respect to the outer ring 2b. It is possible to prevent the destabilization of the liquid from being promoted. Further, even when the inner peripheral surface of the cylindrical portion 35 and the outer peripheral surface of the outer ring of the bearing 33 are in contact with each other, an increase in the rotational resistance of the rotating flange 8a can be suppressed. The distance between the inner peripheral surface and the outer peripheral surface of the outer ring of the bearing 33 can be shortened. As a result, when the impact load is input, the bypass to the outer ring 2b can be promptly performed, or even when the impact load is small, the bypass to the outer ring 2b can be performed. Further, since the mounting tolerance of the bearing 33 and the bypass ring 34 can be relatively loosened, it is possible to prevent an increase in manufacturing cost of the hub unit bearing 1b.

  Since the bearing 33 normally does not rotate except when an impact load is applied to the rotary flange 8a, even if an indentation is formed with the input of the impact load or damage due to fretting wear occurs, There is no particular problem. Furthermore, in this example, since the ball bearing which is a rolling bearing is used as the bearing 33, the stress wave can be absorbed also in the bearing 33. Therefore, since the stress wave input from the bypass ring 34 is attenuated in the bearing 33 and bypassed to the outer ring 2b, damage to the outer ring 2b due to the stress wave can be suppressed.

  From the viewpoint of obtaining an impact load reduction effect due to reflection at the contact portion with the axial inner side surface of the rotating flange, the restraining member supported by the rotating flange does not have a cylindrical portion, that is, for example, A ring-shaped one can also be used. The structure and operational effects of the other parts are the same as in the first example of the embodiment.

  When implementing the hub unit bearing of the present invention, the structures of the examples of the embodiments can be combined as appropriate as long as no contradiction arises. That is, the thin cylindrical portion of the structure of the first example of the embodiment is provided on the shaft portion of the hub formed by combining the first member and the second member as in the second example of the embodiment. Can do. Alternatively, a bypass ring according to the third example of the embodiment may be provided in the structure of the second example of the embodiment.

DESCRIPTION OF SYMBOLS 1, 1a, 1b Hub unit bearing 2, 2a, 2b Outer ring 3, 3a Hub 4 Rolling body 5a, 5b Outer ring raceway 6 Stationary flange 7a, 7b Inner ring raceway 8, 8a, 8b Rotating flange 9, 9a, 9z Small diameter cylinder part 10 DESCRIPTION OF SYMBOLS 10a Hub main body 11 Inner ring 12 Knuckle 13 Thin part 14 Thick part 15 Step part 16 Projection 17 Abutting surface 18 Support hole 19 Mounting hole 20 Stud 21 Caulking part 22 Internal space 23 Seal ring 24 Cover 25 Shaft part 26 Pilot part 27 Solid part 28, 28z Recess 29, 29z Thin tube part 30, 30z Thick tube part 31 Connection cylinder part 32 Intermediate material 33 Bearing 34 Bypass ring 35 Cylindrical part 36 Bending part 37 Through hole 38, 38a Flange part 39 First Member 40 Second member 41 Reinforced portion 42 Fitting recess 43 First through hole 44 Complement Part 45 The second hole 46 the body portion

Claims (5)

An outer member having a double row outer ring raceway on the inner peripheral surface;
An inner member having a double row inner ring raceway on the outer peripheral surface;
Between the double-row outer ring raceway and the double-row inner ring raceway, a plurality of rolling elements arranged in a freely rotatable manner for each row,
The inner member includes a disk-shaped solid portion, a rotating flange having a flange portion protruding radially outward from an outer peripheral portion of the solid portion, and an axial direction from an axial inner surface of the rotating flange. A hollow cylindrical shaft portion that protrudes inward and has the double-row inner ring raceway on the outer peripheral surface, and is located on the axially outer side of the inner ring raceway on the axially outer side of the double-row inner ring raceway. A hub unit bearing having a stress wave suppressing portion for suppressing a stress wave generated in the rotating flange from being transmitted to an axially intermediate portion of the shaft portion.   The shaft portion is present in a portion located between the solid portion and the inner ring raceway on the outer side in the axial direction with respect to the axial direction, and is present on the inner side in the axial direction with respect to the thin tube portion, and The hub unit bearing according to claim 1, further comprising a thick cylindrical portion having a radial thickness that is greater than a radial thickness of the thin cylindrical portion.   The inner member is a solid member, a first member having a to-be-reinforced portion constituting an axially outer portion of the flange portion, a reinforcing portion constituting an axially inner portion of the flange portion, and The hub unit bearing according to claim 1 or 2, comprising a second member having the shaft portion coupled and fixed in the axial direction.   The hub unit bearing according to any one of claims 1 to 3, wherein a suppressing member separate from the inner member is supported by the rotating flange.   The suppression member is a bypass member that is in close proximity to a part of the outer member or a member fixed to the outer member and bypasses the impact load applied to the rotating flange to the outer member. 4. The hub unit bearing according to 4.

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