Bearings – Rotary bearing – Antifriction bearing
Reexamination Certificate
1999-10-29
2001-04-17
Hannon, Thomas R. (Department: 3682)
Bearings
Rotary bearing
Antifriction bearing
C384S448000, C384S477000, C384S544000, C301S108100
Reexamination Certificate
active
06217220
ABSTRACT:
FIELD OF THE INVENTION
The rolling-bearing unit for a road wheel of this invention is used for rotatably supporting with reference to a suspension the non-driven wheels {rear wheels for a FF vehicle (front engine, front-wheel drive) and front wheels for a FR vehicle (front engine, rear-wheel drive) and for a RR vehicle (rear engine, rear-wheel drive)} that are supported by a suspended-type independent suspension of an automobile.
BACKGROUND OF THE INVENTION
In order to rotatably support with reference to the suspension the non-driven wheels that are supported by the suspended-type independent suspension for an automobile, various kinds of rolling-bearing units for road wheel have been used in which the outer ring and hub rotate freely by way of rolling members in combination.
In this kind of rolling-bearing unit for road wheel, the outer ring, which does not rotate even when in use, has a first installation flange around its outer peripheral surface for connecting it to the suspension, and an outer ring raceway around its inner peripheral surface.
In addition, the hub, which rotates when in use, has a second installation flange around its outer peripheral surface on a portion closer to the axially outer end (the term “axially outer” means the side toward the outside in the width direction of the automobile when installed in the automobile) and an inner ring raceway formed around its middle portion directly or by way of an inner ring.
Moreover, by placing the rolling members between the outer ring raceway and inner ring raceway so that they rotate freely, the road wheel that is fastened to the hub is supported rotatably with respect to the suspension to which the outer ring is fastened.
In the case of the rolling-bearing unit for road wheel used for supporting the non-driven wheels in this way, the hub does not particularly require a through hole that penetrates its center section and thus can be made solid.
On the other hand, in the case of a rolling-bearing unit for road wheel that is used for rotatably supporting the driven wheels {the front wheels for a FF vehicle, rear wheels for a FR and RR vehicle and all four wheels for a 4WD vehicle (four-wheel drive vehicle)} with respect to the suspension, it is necessary to connect the shaft of the constant velocity joint with the hub to which the road wheels are fastened. Accordingly, generally a through hole is formed in the hub through which the shaft is inserted.
Furthermore, as shown in
FIG. 1
, a rolling-bearing unit for road wheel used for supporting the non-driven wheels has been known and has actually been used. This construction uses common components for the rolling-bearing unit for road wheel for both the driven wheels and the non-driven wheels.
The outer ring
1
, which does not rotate when installed in the vehicle and supported by the suspension, has a first installation flange
2
around its outer peripheral surface for supporting it by the suspension, and double rows of outer ring raceways
3
around its inner peripheral surface, respectively.
A hollow cylindrical-shaped hub
4
and inner ring
5
are located on the inside of the outer ring
1
and rotatable during use. Of these, the hub
4
has a second installation flange
6
around its outer peripheral surface on the axially outer end (left end in
FIG. 1
) for attaching it to the road wheel, and a first inner ring raceway
7
a
in its middle portion, as well as a through hole
8
that penetrates its center in the axial direction. Also, a second inner ring raceway
7
b
is formed around the outer peripheral surface of the inner ring
5
, and the inner ring
5
is fitted around the outer peripheral surface on the axially inner end of the hub
4
(the term “axially inner” means is the side toward the center in the width direction when mounted on the automobile, the right in
FIGS. 1
thru
14
, and the left in FIG.
2
).
A bolt
9
is inserted through the inside of the through hole
8
, and a nut
10
is fastened to the tip end of this bolt
9
that sticks out from the axially outer end of the hub
4
, and by tightening it securely, the hub
4
and inner ring
5
are held between the head
11
of the bolt
9
and the nut
10
such that the hub
4
and inner ring
5
are joined together as one body.
In addition, multiple rolling members (balls)
12
are placed between the outer ring raceways
3
and the inner ring raceways
7
a
,
7
b
such that they can roll freely.
Moreover, a short, cylindrical shaped cover
14
with a bottom, that is also referred to as a first seal member in the present specification, is formed by bending sheet metal and attached to the opening on the axially inner end of the outer ring
1
.
Together with this, a seal ring
13
, which is also referred to as a second seal member in this specification, is located between the opening edge on the axially outer end of the outer ring
1
and the outer peripheral surface in the middle portion of the hub
4
. These seal members prevent foreign matter such as mud, dust, dirt and the like from getting inside the space
15
where the rolling members
12
are located, and they also prevent lubrication grease that is in this space
15
from leaking out.
When the rolling-bearing unit for road wheel that is constructed as described above is being used, the first installation flange
2
that is formed on the outer ring
1
is fastened to part of the suspension (not shown in the figures) and the second installation flange
6
that is formed around the hub
4
is fastened to the non-driven wheel (not shown in the figures).
When the rolling-bearing unit for road wheel supports the non-driven wheel as shown in
FIG. 1
, it is possible to make the hub common with the rolling-bearing unit which supports the driven wheel. In other words, as mentioned above, in the case of a general rolling-bearing unit for road wheel which supports the driven wheel, it is necessary to have a hole (this is generally a spline hole) through the center of the hub through which the constant velocity joint can pass.
As to this hole, with the construction shown in
FIG. 1
, there is a through hole
8
through the center of the hub
4
, so that there is no need to make a separate hole in the hub because of the existence of this through hole
8
. The through hole
8
in the hub
4
for the non-driven wheel can be used as is before forming a spline, and thus it is possible to keep down the rising costs that accompany the formation of a spline.
In the case of the construction shown in
FIG. 1
, since the opening on the axially inner end of the through hole
8
is sealed tight by the bolt
9
and nut
10
, it is possible to prevent the lubrication grease in the space
15
from getting inside this through hole
8
, and thus it is not necessary to increase the amount of grease used.
Moreover, a rolling-bearing unit for road wheel as shown in
FIG. 2
has been disclosed in U.S. Pat. No. 3,589,747. In the case of this rolling-bearing unit for road wheel, a hollow, cylindrical shaped hub
4
and the inner ring
5
, which is fitted around the hub
4
on the axially inner end (left side in FIG.
2
), are supported on the inside of the outer ring
1
by a tapered roller bearing such that they can rotate freely with respect to the outer ring
1
. Therefore, a pair of tapered concave shaped outer ring raceways
54
are formed around the inner peripheral surface on both ends in the axial direction of the outer ring
1
such that they are tapered in opposite directions. Moreover, tapered convex shaped inner ring raceways
55
a
,
55
b
are formed around the outer peripheral surface in the middle portion of the hub
4
and around the outer peripheral surface of the inner ring
5
, respectively, such that they are tapered in opposite directions.
Also, multiple tapered rollers
56
are located between the outer ring raceways
54
and the inner ring raceways
55
a
,
55
b
such that they can roll freely.
Furthermore, in the case of the construction shown in the figure, in order to fasten the inner ring
5
to the axially inner end of the hu
Ohkuma Takeo
Ouchi Hideo
Evenson, McKeown, Edwards & Lenahan P.L.L.C.
Hannon Thomas R.
NSK Ltd.
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