Metal working – Method of mechanical manufacture – Wheel making
Reexamination Certificate
2001-11-26
2004-08-31
Omgba, Essama (Department: 3726)
Metal working
Method of mechanical manufacture
Wheel making
C029S725000, C029S894360, C029S898070, C072S067000, C072S115000, C072S370030, C072S370100, C072S370110
Reexamination Certificate
active
06782622
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a wheel-supporting hub unit for supporting wheels of a vehicle on a suspension of the vehicle in a freely rotatable manner and a pressing mold for manufacturing same hub unit.
The wheels of the vehicle are supported on the suspension by the wheel-supporting hub unit.
FIGS. 9A and 10
show an example of the wheel-supporting hub unit for supporting the wheels of the car (rear wheels of a FR car, front wheels of a FF car, all wheels of a 4WD car) on the suspension of the car, which is disclosed in Japanese Patent Unexamined Publication No.Hei 11-5404. In an outside end portion of an outer peripheral surface of a hub
2
forming the present wheel-supporting hub unit, there is disposed a flange
3
. Here, a term “outer” side means a side of the hub
2
that is near to outside the car in the width direction of the car in a state where the hub
2
is assembled to the car. In
FIGS. 9A and 10
, the term “outer” side means the left side. On the other hand, the side of the hub
2
that is near to the center of the car in the width direction of the car is referred to as a “inner” side. In
FIGS. 9A and 10
, the “inner” side means the right side. In the middle portion of the outer peripheral surface of the hub
2
, there is formed an inner raceway
4
which corresponds to a first inner raceway. In the inside end portion of the outer peripheral surface of the hub
2
, there is formed a small-diameter stepped portion
5
. An inner ring
6
includes another inner raceway
4
corresponding to a second inner raceway in its outer peripheral surface.
In
FIG. 9B
, as the same as above structure of the wheel supporting hub unit, in the inside end portion of the outer peripheral surface of the hub
2
, there is formed a small-diameter stepped portion
5
. An inner ring
6
includes inner raceway
4
corresponding to a first inner raceway and a second inner raceway in its outer peripheral surface. In
FIGS. 9A
,
9
B and
10
, the inner ring
6
is fitted with the outer surface of the small-diameter stepped portion
5
, and the inside end face of the inner ring
6
is held by a caulking portion
7
formed in the inside end portion of the hub
2
. The inner ring
6
is held by and between the caulking portion
7
and a stepped surface of the small-diameter stepped portion
5
, thereby the inner ring
6
is fixed to the hub
2
.
On the periphery of the hub
2
, there is disposed an outer ring
8
in such a manner that it is concentric with the hub
2
. In the inner peripheral surface of the outer ring
8
, there are formed a pair of outer raceways
9
,
9
corresponding to the first and second inner raceways.
Between the outer raceways
9
,
9
and the inner raceways
4
,
4
, there are disposed rolling elements
10
,
10
respectively two or more in number. In the illustrated embodiment, as the respective rolling elements
10
,
10
, there are used balls, however, in the case of a wheel-supporting hub unit for a car which is large in weight, taper rollers may also be used as the rolling elements.
Further, the hub
2
is formed in a cylindrical shape. In the inner peripheral surface of the hub
2
, there is formed a female spline portion
11
. On the female spline portion
11
, there is disposed a constant-velocity joint
12
. A drive shaft
13
includes a male spline portion formed in its outer peripheral surface and is inserted into the constant-velocity joint
12
. A nut
14
is threadedly engaged with the leading end portion of the drive shaft
13
. A stepped portion
15
is formed in the base end portion of the drive shaft
13
. The inside end face of the nut
14
is contacted with the outside end face of the hub
2
. The stepped surface
16
of the stepped portion
15
is contacted with the inside end face of the caulking portion
7
formed in the inside end portion of the hub
2
. In this contact state, by fastening the nut
14
, the hub
2
can be connected to the drive shaft
13
. In the inside end face of the caulking portion
7
, a flat portion
17
is formed to secure a contact area of the caulking portion
7
with respect to the stepped surface
16
. The flat portion prevents the contact area from being deformed elastically and collapsing through plastic deformation.
In the outer peripheral surface of the outer ring
8
, there is formed an outwardly-facing flange-shaped mounting portion
18
. To assemble the above-structured wheel-supporting hub unit
1
to the car, the outer ring
8
is fixed to a suspension through the outwardly-facing flange-shaped mounting portion
18
, and the wheels of the car is fixed to the flange
3
. As a result of this, the wheels can be rotatably supported on the suspension. Alternatively, by driving the drive shaft
13
of the constant-velocity joint
12
rotationally through a rotation transmission shaft (not shown) with its base end portion connected to a differential gear (not shown), the hub
2
and the wheels fixed to the hub
2
can be driven or rotated.
When forming the caulking portion
7
in the inside end portion of the hub
2
so as to be shown the conventional structure in
FIGS. 9A
,
9
B and
10
, a cylindrical portion
19
formed in the inside end portion of the hub
2
is strongly pressed by a pressing mold. Then, the cylindrical portion
19
is plastic deformed outwardly in the diameter direction thereof. In this case, to the cylindrical portion
19
, there are applied not only a force going outwardly in the diameter direction but also a large force going outwardly in the axial direction. Further, in the final stage of such working or plastic deforming operation, a force that goes inwardly in the diameter direction is also applied to the cylindrical portion
19
. There is a possibility that, of these three kinds of forces, due to the two forces respectively going outwardly in the axial direction and going inwardly in the diameter direction, a part of the cylindrical portion
19
can be bulged and deformed inwardly in the diameter direction. In a case that the part of the cylindrical portion
19
is deformed inwardly in the diameter direction, there is a possibility that the drive shaft
13
of the constant-velocity joint
12
cannot be inserted into the female spline portion
11
formed in the central portion of the hub
2
.
Further, there is another possibility that the fitted portion between the inner peripheral surface of the inner ring
6
and the outer peripheral surface of the cylindrical portion
19
can provide a clearance-fit in a part.
In a case that the fitted state provides such clearance-fit, a phenomenon called “creep”, where the inner ring
6
rotates with respect to the hub
2
, is easy to occur. In the case of the creep occurring, as the wheel-supporting hub unit
1
is used for a long period of time, unfavorably, the respective peripheral surfaces forming the above-mentioned fitted portion are worn. Further, a rickety motion is thereby easy to occur in the fitted portion. Especially, in a case that the axial length of the cylindrical portion
19
is large, there is a possibility that the inside diameter of a part of the cylindrical portion
19
can be reduced. The part of the cylindrical portion
19
is a considerable portion of the outer peripheral surface of the cylindrical portion
19
, that is opposed to the inner peripheral surface of the inner ring
6
. In such case, as the above-mentioned creep is easy to occur, it is necessary to prevent the diameter of the cylindrical portion
19
from reduce, with the working operation for forming the caulking portion
7
.
The above-mentioned problem, that the drive shaft
13
cannot be inserted into the female spline portion
11
, is a problem peculiar to a wheel-supporting hub unit for the drive wheels. However, the lowered support strength of the inner ring
6
caused by the occurrence of the clearance-fit can occur not only in a wheel-supporting hub unit for drive wheels but also in a wheel-supporting hub unit for coupled driving wheels (the front wheels of an FR car, and the rear wheels
Hagiwara Nobuyuki
Horike Shoji
NSK Ltd.
Omgba Essama
LandOfFree
Method for manufacturing wheel-supporting hub unit and... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for manufacturing wheel-supporting hub unit and..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for manufacturing wheel-supporting hub unit and... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3347335