JP6364990B2 - Hub unit - Google Patents

Description

  The present invention relates to a hub unit. More particularly, the present invention relates to a hub unit that rotatably supports a wheel of a vehicle such as an automobile with respect to a vehicle suspension system.

  Particularly when the vehicle is traveling at a low speed, vibration may occur when the brake of the disc brake is sandwiched between the brake pads and braking is performed, and unpleasant noise of low frequency may be generated. This phenomenon is called brake judder, and its clear mechanism has not been elucidated at present. However, as one factor, the deflection accuracy of the pad sliding contact surface of the brake rotor is cited.

  Factors that influence the runout accuracy of the pad sliding contact surface of the brake rotor include the runout accuracy of the brake rotor itself and the surface runout accuracy of the wheel mounting flange to which the brake rotor is attached. Various proposals have been made in order to increase this (see, for example, Patent Documents 1 and 2).

  In the structures described in Patent Documents 1 and 2, an annular groove is formed on the flange surface of the wheel mounting flange formed on the outer periphery of the hub shaft on the side where the brake rotor is mounted. And the bolt hole which penetrates the hub bolt for attaching a wheel via the said brake rotor is drilled in the bottom face of the said annular groove.

  In this case, since the bolt hole is drilled in the annular groove, local deformation of the peripheral edge of the bolt hole caused by press-fitting the hub bolt into the bolt hole and undulation generated on the side surface of the wheel mounting flange are caused by the annular ring. As a result, it is possible to suppress the local deformation and waviness from affecting the flange surface outside the annular groove (surface on which the brake rotor abuts).

JP-A-7-164809 JP 2007-176485 A

  However, the present inventor, when the annular groove is formed on the flange surface of the brake rotor as in the structures described in Patent Documents 1 and 2, when the brake rotor and the hub shaft are wet, the hub bolt and the bolt hole If water enters the space between the brake rotor and the annular groove from the gap between the brake rotor and the annular groove, and the invaded water stays in the space for a long time, the water will cause corrosion of the brake rotor, hub axle and hub bolt. I found that there was a fear.

  This invention is made | formed in view of such a situation, and it aims at providing the hub unit which can discharge | release the water which penetrate | invaded the space between a brake rotor and an annular groove.

The hub unit of the present invention includes an outer ring member and an inner ring member disposed coaxially with the outer ring member inside the outer ring member.
A wheel mounting flange for fixing a wheel via a brake rotor is formed on the outer ring member or the inner ring member,
A plurality of bolt holes through which hub bolts for fixing the wheels are inserted are formed in the circumferential direction in the wheel mounting flange, and
A hub unit in which an annular groove including the plurality of bolt holes is formed on a flange surface of the wheel mounting flange on the side on which the brake rotor is mounted,
A drainage passage that penetrates the wheel mounting flange is formed on the bottom surface of the annular groove ,
The drainage channel has both a function for temporarily fixing the brake rotor to the wheel mounting flange and a function for pulling the brake rotor away from the wheel mounting flange when maintaining the brake rotor. No.

  In the hub unit of the present invention, a drainage channel that penetrates the wheel mounting flange is formed on the bottom surface of the annular groove formed on the flange surface of the wheel mounting flange on the side where the brake rotor is mounted. Therefore, even if the brake rotor and the hub axle are wetted and water enters the space between the brake rotor and the annular groove, the water can be discharged to the outside of the hub unit. As a result, it is possible to prevent the brake rotor, the hub shaft, and the hub bolt from being corroded by water that has entered the space between the brake rotor and the annular groove.

  According to the hub unit of the present invention, it is possible to discharge water that has entered the space between the brake rotor and the annular groove.

It is a fragmentary sectional view of one embodiment of the hub unit of the present invention. It is explanatory drawing which looked at the hub axis | shaft in the hub unit shown by FIG. 1 from the outboard side. FIG. 3 is a partial cross-sectional explanatory view of a wheel mounting flange of the hub axle shown in FIG. 2.

Hereinafter, embodiments of the hub unit of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a partial cross-sectional explanatory view of a hub unit according to an embodiment of the present invention, and FIG. 2 is an explanatory view of a hub shaft in the hub unit shown in FIG. In FIG. 1 and FIG. 3 to be described later, the left side is the inboard side, and the right side is the outboard side.

  The hub unit H according to the present embodiment is an axle hub unit on the drive wheel side in a vehicle, and is arranged coaxially with the outer ring member 1 on the inner side of the outer ring member 1 fixed to the vehicle body side and the outer ring member 1. The inner ring member 2 is provided, and seal members 3 a and 3 b disposed at both ends of the annular space S between the outer ring member 1 and the inner ring member 2. A substantially disc-shaped dust cover 5 as viewed from the axial direction is disposed on the outer periphery of the outer ring member 1 in order to prevent a stepping stone from colliding with the sliding surface of the brake rotor 4 during vehicle travel.

  The outer ring member 1 is fixed to the vehicle body side via a knuckle 6. The outer ring member 1 has a double row outer ring raceway surface 1a on its inner peripheral surface, and the inner ring member 2 has an inner ring raceway surface 2a facing the outer ring raceway surface 1a on its outer peripheral surface. Yes. A ball 7 as a rolling element is disposed between the outer ring raceway surface 1a and the inner ring raceway surface 2a.

  The inner ring member 2 includes a hub shaft 8 and a separate inner ring component 9 fitted to the outer diameter of the inboard side end portion of the hub shaft 8. The hub shaft 8 is rotatably supported by the outer ring member 1 via double rows of balls 7.

  The balls 7 are held by the cage 10 at predetermined intervals in the circumferential direction on the inner ring raceway surface 2a. Both ends of the annular space S between the inner ring member 2 and the outer ring member 1 are sealed by seal members 3a and 3b. Both seal members 3a and 3b are arranged mainly to prevent foreign matters (such as muddy water and fine dust) from entering the bearing.

  A wheel mounting flange 11 for mounting a wheel to the hub unit H is formed on the outer periphery of the end portion on the outboard side of the hub shaft 8, and a bolt hole 12 is formed in the peripheral portion of the wheel mounting flange 11. It is drilled at a predetermined interval. The wheel 14 and the brake rotor 4 which are wheel side components are attached to the hub bolt 13 press-fitted into the bolt hole 12. The wheel 14 and the brake rotor 4 are fastened together by a nut 15.

  As shown in FIGS. 2 to 3, an annular groove 16 is formed on the flange surface 11 a on the side to which the brake rotor 4 is mounted, of the flange surface of the wheel mounting flange 11. As described above, the annular groove 16 is formed to increase the surface runout accuracy of the flange surface 11a to which the brake rotor 4 is attached. Specifically, when the hub bolt 13 is press-fitted into the bolt hole 12, local deformation of the peripheral edge of the bolt hole or undulation generated on the flange surface 11a is kept in the annular groove, and the deformation or undulation is outside the annular groove. It is formed in order to suppress the influence on the flange surface 11a.

  The annular groove 16 is formed so as to include the plurality of bolt holes 12. In other words, a plurality (five in this embodiment) of bolt holes 12 are formed in the bottom surface 16a of the annular groove 16. The depth of the annular groove 16 is not particularly limited in the present invention, but is usually about 0.5 mm to 0.9 mm.

  On the bottom surface 16 a of the annular groove 16, a drainage hole 17 is formed as a drainage channel that penetrates the wheel mounting flange 11. This drain hole 17 can be formed using, for example, a drill. In the present embodiment, a drain hole 17 is formed at the center in the circumferential direction of the adjacent hub bolts 13. When a moment load is applied to the hub unit H during vehicle travel, the hub bolt 13 tries to resist the moment load applied. At this time, stress concentration occurs around the hub bolt 13, but the drain hole 17 is formed at the center in the circumferential direction of the adjacent hub bolts 13 to ensure the strength around the hub bolt 13, thereby stress concentration on the flange surface 11 a. The influence can be reduced.

  Even if the drainage hole 17 is formed in the bottom surface 16 a of the annular groove 16, even if the brake rotor 4 and the hub shaft 8 are submerged and water enters the space between the brake rotor 4 and the annular groove 16. The water in this space can be discharged to the outside of the hub unit H through a drain hole 17 that communicates with the space and is formed through the wheel mounting flange 11. Thereby, it can prevent that the water which penetrate | invaded into the space between the brake rotor 4 and the annular groove 16 stays in the said space, and the brake rotor 4, the hub shaft 8, and the hub bolt 13 corrode. The diameter of the drain hole 17 is not particularly limited in the present invention, but is usually about 3 mm to 4 mm. The larger drain hole 17 is easier to drain, but if it is too large, the strength of the wheel mounting flange 11 may be reduced.

In the present embodiment, a screw hole 18 is formed at the center in the circumferential direction of the adjacent hub bolt 13 separately from the drain hole 17. The screw hole 18 is used to temporarily fix the brake rotor 4 to the flange surface 11a when the hub unit H is assembled. When the brake rotor 4 is maintained, the brake hole 18 is fixed to the flange surface 11a by rust or the like. It is used for screwing a bolt for pulling the rotor 4 away from the flange surface 11a.
The drainage hole 17 in the present embodiment functions as a drainage channel for discharging water that has entered the space between the brake rotor 4 and the annular groove 16 to the outside of the hub unit H, and is formed on the inner peripheral surface. There is no threading. The drain hole 17 has both a function for temporarily fixing the brake rotor 4 to the wheel mounting flange 11 and a function for pulling the brake rotor away from the wheel mounting flange during maintenance of the brake rotor. No.

  In the present embodiment, the diameter of the drain hole 17 and the diameter of the pilot hole for forming the screw hole 18 are the same. Furthermore, the radial position of the drain hole 17 and the radial position of the screw hole 18 are the same. Accordingly, the drainage hole 17 and the lower hole can be formed using a common tool (drill) simply by rotating the hub shaft 8, so that the workability is excellent.

[Other variations]
The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims.
For example, in the embodiment described above, only one drain hole is formed, but a plurality of drain holes may be formed.
In the embodiment described above, the drain hole is formed at the center in the circumferential direction of the adjacent hub bolt. However, the drain hole is formed at another position within a range in which the strength of the wheel mounting flange against the applied load is ensured. May be.

  Further, in the above-described embodiment, the drain hole is adopted as a discharge path for discharging water that has entered the space between the brake rotor and the annular groove to the outside. It is also possible to adopt a passage having another cross-sectional shape such as a rectangle or an ellipse whose cross-sectional shape is perpendicular to.

  In the above-described embodiment, the diameter of the drain hole and the diameter of the lower hole of the screw hole are the same, but they may be different from each other. Furthermore, in the embodiment described above, a screw hole is formed on the flange surface separately from the drainage hole, but this screw hole may be omitted depending on the structure of the hub unit.

  In the above-described embodiment, the wheel mounting flange is formed on the outer periphery of the hub shaft constituting the inner ring member. However, the present invention is not limited to this, and the wheel mounting flange is formed on the outer periphery of the outer ring member. The invention can also be applied to the type of hub unit that is formed.

  1: outer ring member, 2: inner ring member, 4: brake rotor, 8: hub axle, 11: wheel mounting flange, 11a: flange surface, 12: bolt hole, 13: hub bolt, 16: annular groove, 16a: bottom surface, 17: Drain hole, 18: Screw hole, H: Hub unit

Claims (3)

An outer ring member, and an inner ring member disposed coaxially with the outer ring member inside the outer ring member,
A wheel mounting flange for fixing a wheel via a brake rotor is formed on the outer ring member or the inner ring member,
A plurality of bolt holes through which hub bolts for fixing the wheels are inserted are formed in the wheel mounting flange along the circumferential direction, and
A hub unit in which an annular groove including the plurality of bolt holes is formed on a flange surface of the wheel mounting flange on the side on which the brake rotor is mounted,
A drainage passage that penetrates the wheel mounting flange is formed on the bottom surface of the annular groove ,
The drainage channel has both a function for temporarily fixing the brake rotor to the wheel mounting flange and a function for pulling the brake rotor away from the wheel mounting flange when maintaining the brake rotor. No hub unit. A screw hole is further formed on the bottom surface of the annular groove,
The drainage channel is a drainage hole whose inner peripheral surface is not threaded, and
The hub unit according to claim 1, wherein a diameter of a pilot hole for forming the screw hole and a diameter of the drain hole are the same. The hub unit according to claim 1, wherein the drainage channel is formed at a circumferential center of adjacent hub bolts.

Images