Metal deforming – By use of tool acting during relative rotation between tool...
Reexamination Certificate
2002-05-24
2004-08-10
Tolan, Ed (Department: 3725)
Metal deforming
By use of tool acting during relative rotation between tool...
C072S112000, C072S115000, C029S894362, C029S898070
Reexamination Certificate
active
06772615
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
A method of manufacturing a hub unit for supporting a wheel and a die for manufacturing it of the present invention are utilized for manufacturing a hub unit for pivotally supporting a wheel of an automobile by a suspension.
2. Description of the Related Art
A wheel of an automobile is supported by a suspension via a hub unit for supporting the wheel.
FIG. 10
is a view showing an example of the hub unit for supporting a wheel described in the U.S. Pat. No. 5,490,732. This hub unit
1
for supporting a wheel includes: a hub body
2
, a pair of inner rings
3
a
,
3
b
, an outer ring
4
, and a plurality of rolling elements
5
,
5
. In this arrangement, in the outside end portion of the outer circumferential face of the hub body
2
, there is provided a flange
6
for supporting a wheel. In this case, the outside of the hub body is defined as a side which becomes an outside in the width direction when the hub is assembled to an automobile, that is, the outside of the hub body is the left in FIG.
10
. On the contrary, the inside of the hub body is defined as a side which becomes a portion close to the center of an automobile, that is, the inside of the hub is the right in FIG.
10
. At a base end portion of the flange
6
close to the center of the hub body
2
, there is provided a step portion
7
.
The pair of inner rings
3
a
,
3
b
, are externally engaged with a portion located in a range from the middle portion to the inside end portion of the hub body
2
. An outside end face of the inner ring
3
a
, which is arranged outside, butts to a step face of the step portion
7
, and an outside end face of the inner ring
3
b
, which is arranged inside, butts to an inner end face of the inner ring
3
a
which is arranged outside. In this connection, when a view is taken from the inner ring
3
b
which is located inside, the inside end face of the inner ring
3
a
, which is located outside, becomes a step face of the step portion. In the inside end portion of the hub body
2
, there is provided a cylindrical portion
8
. A forward half portion of this cylindrical portion
8
, which protrudes inside from the inside end face of the inner ring
3
b
, is plastically deformed in the radial outward direction so that the calking portion
9
can be formed. The pair of inner rings
3
a
,
3
b
are interposed between the calking portion
9
and the step face of the step portion
7
.
Between the pair of outer ring raceways
10
,
10
(the first and the second raceways) provided on the inner circumferential face of the outer ring
4
and the inner ring raceways
11
,
11
(the first and the second inner ring raceways) provided on the outer circumferential faces of the inner rings
3
a
,
3
b
, a plurality of rolling elements
5
,
5
are respectively arranged. In this connection, in the example shown in the drawing, balls are used as the rolling elements
5
,
5
, however, in the case of a hub unit for supporting a wheel used for an automobile, the weight of which is heavy, tapered rollers may be used for the rolling elements. In some cases, the inner ring raceway
11
(the first inner ring raceway) arranged close to the flange
6
may be directly formed on an outer circumferential face of the hub body
2
so as to omit the inner ring
3
a
which is located outside. In this case, the step portion
7
is formed at a position corresponding to the inside of the outside inner ring
3
a
shown in FIG.
10
.
In order to assemble the hub unit
1
for supporting a wheel into an automobile, the outer ring
4
is fixed to the suspension by the attaching portion
12
, the shape of which is formed into an outward flange-shape, which is formed on an outer circumferential face of the outer ring
4
, and a wheel is fixed to the flange
6
. As a result, the wheel can be pivotally supported by the suspension.
Further, Japanese Unexamined Patent Publication No. 10-272903 discloses a structure in which damage such as cracks seldom occurs in the calking portion when the inner ring is fixed and the inner diameter of the inner ring and the diameter of the inner ring raceway formed on the outer circumferential face of the inner ring are difficult to be changed when calking work is carried out.
FIGS. 11
to
15
are views showing the second example of the conventional structure disclosed in the above patent publication and also showing a conventional manufacturing method.
As shown in
FIG. 14
, before the cylindrical portion
8
a
is calked and expanded in the radial outward direction, the wall thickness of the cylindrical portion
8
a
, which is formed in the inside end portion of the hub body
2
so that the calking portion
9
a
for fixing the inner ring
3
can be composed, is gradually reduced when it comes to the forward end edge. Therefore, on the inside end face of the hub body
2
, there is provided a tapered hole
13
, the inner diameter of which is gradually reduced when it comes to the inner portion.
In order to calk and expand the forward end portion of the cylindrical portion
8
a
so that the inner ring
3
can be fixed to the inside end portion of the hub body
2
, the hub body
2
is fixed so that it can not be moved in the axial direction, and the holding piece
14
holds the outer circumferential face of the inner ring
3
as shown in FIG.
15
. While the hub body
2
, on the outer circumferential face of which the inner ring
3
is engaged, is being prevented from fluctuating in the radial direction, as shown in the drawing, the die
15
is strongly pressed against the forward end portion of the cylindrical portion
8
a
. A central portion of the forward end face (lower end face shown in
FIG. 15
) of the die
15
is formed into a protruding portion
16
, the shape of which is a circular truncated cone, which can be freely pushed into the cylindrical portion
8
a
. In the periphery of this protruding portion
16
, there is provided a recess portion
17
, the section of which is an arc, which surrounds the overall circumference of the protruding portion
16
.
On the other hand, in the periphery of the inside end opening of the inner ring
3
to be fixed to the inner end portion (the right end portion shown in
FIG. 11
, the upper end portions shown in
FIGS. 12
to
15
) of the hub body
2
by the calking portion
9
a
, there is provided an inside end face
18
which is a flat face perpendicular to the central axis of this inner ring
3
. The inner circumferential edge of the inside end face
18
and the inner circumferential face
19
of the inner ring
3
, which is a cylindrical face, are continued to each other by the chamfer portion
20
.
The calking portion
9
a
for pressing the inner ring
3
, the shape of the inside end portion of which is formed as described above, against the step portion
7
of the hub body
2
is composed when the cylindrical portion
8
a
is calked and expanded in the radial outward direction. The wall thickness of the calking portion
9
a
is gradually reduced with respect to the wall thickness a
0
of the base end portion of the cylindrical portion
8
a
(
FIG. 12
) when it comes to the forward end portion. That is, as shown in
FIG. 13
, the wall thickness of the base end portion of the calking portion
9
a
is a
0
, and this wall thickness is changed in the order of a
0
, a
1
, a
2
, . . . a
n
when it comes to the forward end portion. In this case, sections of the protruding portion
16
and the recess portion
17
are regulated to form the calking portion
9
a
so that the wall thickness of each portion can be kept in the relation of a
0
>a
1
>a
2
> . . . a
n
and so that the wall thickness a
n
of the forward end portion of the calking portion
9
a
can not become zero (a
n
>0).
When the die
15
having the protruding portion
16
and the recess portion
17
is incorporated into an oscillating calking device and the die
15
is pressed against the forward end portion of the cylindrical portion
8
a
, it is possible to calk and expand the forward end portion of the cylindrical portion
8
a
in
Hagiwara Nobuyuki
Horike Shoji
NSK Ltd.
Tolan Ed
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