Bearings – Rotary bearing – Antifriction bearing
Reexamination Certificate
2000-06-12
2002-12-24
Hannon, Thomas R. (Department: 3682)
Bearings
Rotary bearing
Antifriction bearing
C384S589000, C464S178000, C029S898062
Reexamination Certificate
active
06497515
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a bearing apparatus for a wheel for supporting a wheel of an automobile, and more particularly to a bearing apparatus for a wheel of a type that a hub, an outer joint member of a constant velocity universal joint and double rows of wheel bearings are united and at least one of the double rows of inner raceways is integrally formed in the outer joint member, or of a type that one of the inner raceways is directly formed in the hub and another of the inner raceways is formed in an inner race fitted to the hub.
Driving wheels of the automobile such as rear wheels of an FR vehicle, front wheels of an FF vehicle and all wheels of a 4WD vehicle are supported to a suspension apparatus by a bearing apparatus for wheels. The bearing apparatus mentioned above is structured, as shown in
FIG. 43
, such that a hub
10
, a bearing
20
and a constant velocity universal joint
30
are united, one inner raceway
12
of double rows of inner raceways is formed in the hub
10
, and another inner raceway
42
is formed in an outer joint member
40
of the constant velocity universal joint
30
.
The hub
10
has a flange
14
for supporting the wheel, and the inner raceway
12
is formed on an outer peripheral surface close to the flange
14
. The outer joint member
40
of the constant velocity universal joint
30
is constituted by a bowl-shaped mouth portion
43
and a solid stem portion
45
, and is serration fitted to the hub
10
at the stem portion
45
and a shoulder surface
44
thereof is brought into contact with an end surface of the hub
10
. The inner raceway
42
is formed on an outer peripheral surface close to the stem portion
45
in the mouth portion
43
of the outer joint member
40
. Double rows of outer raceways
22
opposing to the inner raceways
12
,
42
are formed on an inner peripheral surface of an outer member
21
(hereinafter, refer to as an outer race) of the bearing
20
. Rolling elements
29
are assembled between the inner raceways
12
,
42
and the outer raceways
22
.
As shown by a reference numeral
45
′, an axial end of the stem portion
45
protruding from the hub
10
is caulked, thereby connecting between the hub
10
and the stem portion
45
, and the outer race
21
is fixed to the suspension apparatus by a flange
24
formed on the outer peripheral surface of the outer race
21
, whereby the wheel is fixed to the flange
14
of the hub
10
.
In the bearing apparatus mentioned above, a torque from an engine is transmitted to the hub
10
via the constant velocity universal joint
30
so as to rotate the wheel. Accordingly, it is necessary that the outer joint member
40
and the hub
10
are connected at a high reliability. However, since a great moment load is applied to the bearing portion particularly when the automobile turns, there is a disadvantage that the caulked portion is loosened in the case of caulking the axial end of the stem portion
45
of the outer joint member
40
.
The bearing apparatus mentioned above is that one inner raceway
42
of the double rows of inner raceways
12
,
42
is integrally formed with the outer joint member
40
, however, as a bearing apparatus having another construction, there is a bearing apparatus structured such that one inner raceway is directly formed in the hub and another inner raceway is formed in an inner race fitted to the hub as an independent element from the hub.
FIGS. 44A and 44B
show a representative embodiment of the bearing apparatus, in which
FIG. 44A
shows the bearing apparatus for a driving wheel and
FIG. 44B
shows the bearing apparatus for a driven wheel. Since a basic structure is common between the bearing apparatus for the driving wheel and the bearing apparatus for the driven wheel, a brief description will be given of a construction of the bearing apparatus for the driven wheel in accordance with FIG.
44
A. The bearing apparatus is structured such that the hub
10
, an inner race
80
, the outer race
21
, the double rows of rolling elements
29
and the constant velocity universal joint
30
are united. One inner raceway
12
of the double rows of inner raceways
12
,
42
is directly formed in the hub
10
and another inner raceway
42
is formed in the inner race
80
fitted to the hub
10
as an independent element from the hub
10
.
The hub
10
is structured such that the inner raceway
12
is formed in the outer peripheral portion and the flange
14
for supporting the wheel is formed in the end portion close to an outboard side. In this case, a side close to an outer side of the vehicle in a state of being assembled in the vehicle is called as an outboard side (a left side in the drawing) and a side close to a center portion of the vehicle is called as an inboard side (a right side in the drawing). A small diameter step portion
59
having a reduced outer size is formed in the inboard side end portion of the hub
10
, and the inner race
80
independent from the hub
10
and having the inner raceway
42
formed on the outer peripheral surface is fitted to the small diameter step portion
59
. Double rows of outer raceways
22
opposing to the inner raceways
12
,
42
are formed on the inner peripheral surface of the outer race
21
. The rolling elements
29
are interposed to be freely rotatable between the inner raceways
12
,
42
and the outer raceways
22
.
The outer race
21
is fixed to the suspension apparatus by the flange
24
(in
FIG. 44
, only a part thereof appears) formed on the outer peripheral surface of the outer race
21
, whereby the wheel is fixed to the flange
14
of the hub
10
. The stem portion
45
of the outer joint member
40
is serration fitted to a serration hole
63
of the hub
10
, thereby transmitting a rotational drive force to the wheel fixed to the hub
10
. A nut
69
is screwed to a male screw portion
67
at the front end portion of the stem portion
45
, thereby connecting the bearing
20
and the constant velocity universal joint
30
.
This kind of bearing apparatus is normally used by applying a pre-load to the bearing
20
, and an accurate pre-load control is performed at a time of assembling. However, since the inner raceways
12
,
42
are distributed to the hub
10
and the inner race
80
, a change of a positional relation in an axial direction between the hub
10
and the inner race
80
results in a change of a size between the inner raceway
12
and the inner raceway
42
, so that the bearing clearance changes and causes a pre-load omission. Accordingly, it is necessary that the hub
10
and the inner race
80
are connected to each other at a high reliability.
However, since a great moment load is applied to the bearing portion particularly when the automobile turns, there is a disadvantage that the caulked portion is loosened due to a spring back of the caulked portion or the other reasons in the case of caulking the axial end of the small diameter step portion
59
in the conventional hub
10
. Further, the hub
10
a nd the inner race
80
has a relation pressure fitting with a interference, however, no specific device has been conventionally provided so as to prevent a relative rotation. Accordingly, when the relative rotation, that is, a creep is generated due to some reason, there is generated a problem that a damage is generated on the fitting surface between the hub
10
and the inner race
80
, a seizure is generated and a interference is increased, whereby a service life is reduced.
SUMMARY OF THE INVENTION
A first object of the present invention is to prevent the hub and the constant velocity universal joint from being loosened. To achieve the foregoing object, the invention provides a bearing apparatus for a wheel which comprises a hub, a constant velocity universal joint and a bearing, these elements being united and at least one of double rows of inner raceways of the bearing being integrally formed with an outer joint member of the constant velocity universal joint, wherein the hub and the outer joint member are fitted to each other, a
Hozumi Kazuhiko
Ohtsuki Hisashi
Ozawa Masahiro
Sahashi Koji
Sone Keisuke
Arent Fox Kintner & Plotkin & Kahn, PLLC
Hannon Thomas R.
NTN Corporation
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