JP3881149B2 - Hub unit - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a hub unit to which wheels are attached.
[0002]
[Prior art]
A basic configuration of this type of conventional hub unit is shown in FIG. Here, a hub unit used on the drive wheel side is taken as an example. In the figure, 1 is a hub unit, 2 is a hub wheel, 3 is a double row outward angular ball bearing, 4 is a drive shaft, 5 is a disk rotor of a disk brake device, 6 is a shaft case, and 7 is a brake pad.
[0003]
The disk rotor 5 is attached in a state of being applied to the outer end surface of the flange 10 of the hub wheel 2. The disk rotor 5 is fixed by bolts 12 that are inserted in through holes 11 provided in several places on the circumference of the flange 10 in a non-separated state.
[0004]
In the first place, since the disk rotor 5 is attached after the hub unit 1 is attached to the drive shaft 4, the bolts 12 must be attached to the through holes 11 of the flange 10 in advance. Further, when handling the hub unit 1 alone, it is difficult to drop the bolt 12 described above, so the bolt 12 is attached to the through hole 11 in a non-separable manner.
[0005]
Conventionally, in order to fix the bolt 12 described above to the through hole 11 in a non-separable manner, a serration 13 is formed in a region on the head side in the screw shaft portion of the bolt 12, and the outer diameter of the serration 13 is passed through By forming it larger than the inner diameter of the inner surface of the hole 11, the serration 13 can be press-fitted so as to bite into the inner surface of the through hole 11. For the press-fitting, a necessary press-fitting allowance is required by making the outer diameter of the serration 13 larger than the inner diameter of the inner surface of the through hole 11.
[0006]
[Problems to be solved by the invention]
By the way, when the serration 13 is press-fitted into the inner surface of the through hole 11, as shown in FIG. 10, the flesh around the through hole 11 flows as indicated by the arrow, and the flange 10 is distorted. Such distortion in the flange 10 increases as the press-fitting margin increases, and the adhesion of the disc rotor 5 to the surface of the flange 10 is further reduced.
[0007]
Therefore, in order to reduce the distortion and improve the adhesion of the disk rotor 5, the press-fitting allowance must be set small. However, if the press-fitting allowance is set small, the slip torque and the pulling force are reduced.
[0008]
Here, the slip torque is a torque that prevents the bolt 12 from slipping and rotating on the inner surface of the through-hole 11 due to the force in the rotational direction acting on the bolt 12. This is the force that prevents the bolt 12 from falling off between the bolt 12 and the through-hole 11 due to the action of an axial force from the through-hole 11 acting.
[0009]
In view of such circumstances, the present invention provides a hub unit in which the press-fitting allowance is set small so that the distortion of the flange is reduced and the adhesion of the disc rotor to the surface of the flange can be improved. Therefore, it is a common problem to be solved that it is possible to sufficiently secure slip torque and removal force even when the press-fitting allowance is small and to prevent the bolt from rotating so as not to loosen.
[0010]
[Means for Solving the Problems]
A hub unit of the present invention is a hub unit in which a disc rotor of a disc brake device is attached to an outer end face of a radially outward flange of a hub wheel, and is used for wheel attachment that is press-fitted into a through hole provided in the flange. Two serrations arranged at least in the axial direction are formed on the head side of the bolt, and the front side serration with respect to the press-fitting direction of the bolt is an outer diameter that is press-fitted into the inner surface of the through hole with a predetermined press-fitting allowance, The rear side serration is smaller than the outer diameter of the front side serration so that the rear side serration is press-fitted with a press-fitting allowance smaller than the press-fitting allowance, and the number of teeth on each of the front side serration and the rear side serration is Are the same number as each other, and each tooth portion has the same phase relationship when viewed from the axial direction of the bolt, and the root diameter of the front side serration The inner surface of the through hole that has the same diameter at the bottom of the rear serration and the rear serration reduces the diameter of the through hole by a springback phenomenon after passing the front serration through the inner surface of the through hole. The front side opening in the press-fitting direction in the through-hole of the flange is a tapered surface that expands outward, and the front-side serration passes through the inner surface of the through-hole and then the taper surface. The outer peripheral edge on the rear side in the press-fitting direction is locked and prevented from coming off.
[0011]
According to the present invention, when a bolt having two stages of serrations is press-fitted into the through hole, the serration is transferred and formed on the inner surface of the through hole while the front serration of the bolt temporarily enlarges the hole diameter of the through hole. However, when the front serration passes, the hole diameter immediately shrinks due to the springback phenomenon, and when the rear serration of the bolt enters the through hole, the rear serration is inside the through hole. It will be inserted with the necessary press-fitting allowance for the serration. For this reason, in the process of press-fitting bolts into the through holes, the flange is temporarily distorted when the front serration passes, but after the front serration passes, the flange distortion is caused by the springback phenomenon. Returning to the original state, the distortion is reduced and the deformation of the flange can be reduced. Since the rear side serration stops in the through hole, the bolt is prevented from rotating in the through hole by the biting action of the rear side serration on the through hole.
[0012]
In addition, since the inner surface of the through hole is formed with a front serration groove having a large press-fitting allowance relative to the inner surface, slip torque is secured even if the rear serration has a small press-fitting allowance to the inner surface. Therefore, the bolt is fixed to the through hole in a non-separable manner so as not to loosen on the inner surface of the through hole.
[0013]
Furthermore, since the outer peripheral edge in the press-fitting direction rear side of the front serration after passing through the through-hole is locked to the front-side opening in the press-fitting direction in the through hole of the flange, the bolt pull-out force is also ensured.
[0014]
From the above, in the case of the present invention, it is possible to secure the slip torque and the detachment force and to fix the bolts to the through-holes so as not to loosen, while reducing the press-fitting allowance and suppressing the deformation of the flanges. .
[0015]
As a preferred embodiment of the present invention, the front side opening in the press-fitting direction in the through hole of the flange is a tapered surface whose diameter is increased outward, and the front side serration is passed through the inner surface of the through hole and then the taper surface. The outer peripheral edge on the rear side in the press-fitting direction is locked and prevented from coming off. In the case of this embodiment, when a force in the pulling direction is applied to the bolt, it is preferable that the outer peripheral edge of the front side serration in the press-fitting direction bites into the taper surface, and the above-described retaining state is not rattled.
[0016]
As a further preferred embodiment of the present invention, the number of teeth on the front side serration and the number of teeth on the rear side serration are the same, and the teeth are seen from the axial direction of the bolt and have the same phase relationship. .
[0017]
In the case of this embodiment, after the front side serration passes through the inner surface of the through hole, the rear side serration can be easily press-fitted into the inner surface, and the bolt can be easily attached to the through hole of the flange.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
The details of the present invention will be described based on embodiments shown in the drawings.
[0019]
1 to 8 relate to a hub unit according to an embodiment of the present invention, FIG. 1 is a longitudinal side view showing a hub unit for a drive wheel of the embodiment, and FIG. 2 is an enlarged cross-sectional view of a main part of FIG. FIG. 3 is a front view partially showing the front and rear serrations formed on the bolt of FIG.
[0020]
4 is a sectional view for explaining the press-fitting of a bolt into the through hole of the flange of FIG. 1, FIG. 5 is a partial front view of the front side serration shown in FIG. 4, and FIG. FIG. 7 is a partial front view of the front side serration shown in FIG. 6, and FIG. 8 is a partial front view of the rear side serration shown in FIG. 6. It is.
[0021]
The overall configuration of the hub unit in the embodiment is the same as that of the hub unit of FIG. 9 presented in the conventional example except for the flange 10 and the bolt 12, and detailed description thereof is omitted. In FIG. 1 to FIG. 8, the parts corresponding to those in FIG. 1 and FIG.
[0022]
The hub unit 1 according to the embodiment secures slip torque and pull-out force and can be fixed to the through hole 11 in a non-separable manner so that the bolt 12 does not loosen, while reducing the press-fitting allowance and suppressing deformation of the flange 10 to a small extent. It is characterized by having the following structure as possible.
[0023]
That is, two front serrations 14 and 15 rear serrations 14 and 15 are formed on the head side of the bolt 12 in the axial direction.
[0024]
The outer dimension of the front side serration 14 is set larger than that of the rear side serration 15.
[0025]
The front-side serration 14 is on the front side with respect to the press-fitting direction of the bolt 12 with respect to the inner surface of the through-hole 11 and has an outer diameter that is press-fitted with a predetermined press-fitting allowance into the inner surface of the through-hole 11. Yes.
[0026]
The rear side serration 15 is on the rear side with respect to the press-fitting direction with respect to the inner surface of the through hole 11, and has an outer diameter that is press-fitted with a press-fitting allowance smaller than the press-fitting allowance in the front-side serration 14.
[0027]
These press-fitting allowances may be appropriately determined through experiments for slip torque, pull-out force, the degree of deformation of the flange 10, and the like.
[0028]
The front side serration 14 and the rear side serration 15 have a plurality of tooth portions 14a, 15a in the circumferential direction, and the number of the tooth portions 14a, 15a is the same as each other, as shown in FIG. As seen from the direction, each tooth portion 14a, 15a has the same phase relationship, that is, the phase θ between the adjacent peak portions in each tooth portion 14a of the front side serration 14, and the peak portion adjacent in each tooth portion 15a of the rear side serration 15. The phase θ between them has the same phase relationship.
[0029]
In the present invention, it is preferable for the front side serration 14 and the rear side serration 15 to have such a phase relationship in order to ensure slip torque, but it is not always essential.
[0030]
A front side opening in the press-fitting direction of the bolt 12 in the through hole 11 of the flange 10 is a tapered surface 11a that expands outward.
[0031]
In the present invention, the tapered surface 11a is preferable but not necessarily essential for securing the removal force.
[0032]
In the above configuration, when the bolt 12 is inserted into the inner surface of the through hole 11 of the flange 10, the front side serration 14 is first press-fitted into the inner surface of the through hole 11 as shown in FIG. In this case, as shown in FIG. 5, the inner diameter of the through hole 11 of the flange 10 is enlarged by the press-fitting allowance with the inner surface of the through hole 11 in the front side serration 14.
[0033]
When the bolt 12 is further inserted from this state, the rear side serration 15 is press-fitted into the inner surface of the through hole 11 as shown in FIG. At this time, since each tooth portion 14a of the front side serration 14 and each tooth portion 15a of the rear side serration 15 have the same phase relationship, each tooth portion 15a of the rear side serration 15 is caused by the front side serration 14. By phase matching with each groove on the inner surface of the created through hole 11, it is possible to easily press fit into the inner surface of the through hole 11.
[0034]
When the front side serration 14 and the rear side serration 15 are press-fitted into the inner surface of the through hole 11 as described above, the inner surface of the through hole 11 of the flange 10 is expanded in diameter as shown in FIGS. Yes.
[0035]
In this case, the inner surface of the through hole 11 of the flange 10 is expanded in diameter by the press-fitting allowance between the flange 10 and the flange 10 is distorted, and the flange 10 is greatly deformed. Further, as shown in FIG. 2, when the serration 14 passes through the inner surface of the through hole 11, the spring back phenomenon, that is, the phenomenon in which the flange 10 tries to restore the original state by its elastic action, The inner surface of the through hole 11 is reduced in diameter, and the deformation of the flange 10 is suppressed to be small.
[0036]
Since the press-fitting allowance of the rear side serration 15 is smaller than that of the front side serration 14, the deformation of the flange 10 by the rear side serration 15 is small, and the rear side serration 15 is in close contact with the inner surface of the through hole 11. Stay in the press-fit state. The bolt 12 is prevented from rotating by the biting action of the rear side serration 15 with respect to the through hole 11. Therefore, in the embodiment, since the rear side serration 15 having a small press-fitting allowance is press-fitted into the through hole 11, the axial runout of the flange 10 surface is suppressed to be small.
[0037]
From the above, according to this embodiment, since the deep groove is formed in the inner surface of the through hole 11 by the front side serration 14 having a large press-fitting allowance with respect to the inner surface, the rear side serration 15 is formed in the through hole 11. Even if the press-fitting allowance with respect to the inner surface of the through hole 11 is small, the bolt 12 is fixed to the inner surface of the through hole 11 in a non-separable manner so as not to be loosened because the slip torque is secured and pressed into the inner surface of the through hole 11. Is done.
[0038]
Furthermore, since the outer peripheral edge on the rear side in the press-fitting direction of the front-side serration 14 after passing through the through-hole 11 is engaged with the front-side opening in the press-fitting direction in the through-hole 11 of the flange 10, a bolt pull-out force is also ensured.
[0039]
In this case, since the front side serration 14 bites into the tapered surface 11 a of the through hole 11 and the outer peripheral edge on the rear side in the press-fitting direction is locked and prevented from coming off, the bolt 12 rattles the inner surface of the through hole 11. It is fixed without.
[0040]
In addition, although the hub unit 1 of the said embodiment was for drive wheels, this invention is applicable also to the thing for driven wheels.
[0041]
【The invention's effect】
According to the present invention, the two serrations arranged at least in the axial direction are formed on the head side of the wheel mounting bolt that is press-fitted into the through hole provided in the flange, and the front side serration is formed with respect to the press-fitting direction of the bolt. The inner diameter of the through-hole is set to an outer diameter that is press-fitted with a predetermined press-fitting allowance, and the rear side serration is set to an outer diameter that is press-fitted with a press-fitting allowance smaller than the press-fitting allowance with respect to the press-fitting direction. The rear serration is press-fitted into the inner surface of the through-hole which is reduced in diameter by the springback phenomenon of the inner surface of the through-hole after passing through the inner surface of the hole, so that the bolt is loosened by securing slip torque and removal force. It is possible to fix it to the through hole in a non-separable manner, while reducing the press-fitting allowance and suppressing the flange deformation.
[Brief description of the drawings]
1 is a longitudinal side view of a hub unit according to an embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view of a main part of FIG. 1. FIG. 3 is a front side and a rear side formed on the bolt of FIG. FIG. 4 is a sectional view for explaining the press-fitting of bolts into the through holes of the flange of FIG. 1. FIG. 5 is a partial front view of the front side serration shown in FIG. 6 is a sectional view for explaining the press-fitting of a bolt into the through hole of the flange shown in FIG. 1. FIG. 7 is a partial front view of the front serration shown in FIG. 6. FIG. 8 is a rear side shown in FIG. Partial front view of serration [FIG. 9] Longitudinal side view of conventional hub unit [FIG. 10] Enlarged sectional view of essential parts of FIG.
DESCRIPTION OF SYMBOLS 1 Hub unit 2 Hub wheel 3 Drive shaft 5 Disc rotor 10 Hub wheel flange 11 Flange through-hole 11a Tapered surface 12 of through-hole 11 Bolt 14 Front side serration 15 Bolt rear side serration

Claims (1)

A hub unit in which a disc rotor of a disc brake device is attached to an outer end surface of a radially outward flange of a hub wheel,
Forming two serrations lined up at least in the axial direction on the head side of the wheel mounting bolt press-fitted into a through hole provided in the flange;
The front side serration with respect to the press-fitting direction of the bolt is an outer diameter that is press-fitted with a predetermined press-fitting allowance into the inner surface of the through-hole,
The outer diameter of the rear side serration is smaller than the outer diameter of the front side serration so that the rear side serration is press-fitted with a press-fitting allowance smaller than the press-fitting allowance with respect to the press-fitting direction,
The number of teeth on each of the front side serration and the rear side serration is the same as each other, and each tooth has an in-phase relationship when viewed from the axial direction of the bolt,
The root diameter of the front side serration and the rear side serration root diameter are the same,
The rear side serration is press-fitted in a state of being in close contact with the inner surface of the through hole that is reduced in diameter by a springback phenomenon of the inner surface of the through hole after passing the front side serration while being press-fitted into the inner surface of the through hole.
The front-side opening in the press-fitting direction in the through-hole of the flange is a tapered surface that expands outward, and the front-side serration has a rear-side outer peripheral edge in the press-fitting direction with respect to the tapered surface after passing through the inner surface of the through-hole. A hub unit characterized by being locked and prevented from coming off.

Images