Brakes – Vehicle – Hub or disk
Reexamination Certificate
2001-07-03
2003-12-23
Butler, Douglas C. (Department: 3683)
Brakes
Vehicle
Hub or disk
C188S21800R, C188S2180XL, C188S073350, C301S006100, C301S006800, C301S105100, C384S544000
Reexamination Certificate
active
06666303
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a wheel bearing assembly for supporting a vehicle wheel.
Among vehicle wheel bearing assemblies, there are ones for supporting driving wheels and ones for supporting non-driving wheels. Among both types of wheel bearing assemblies, there are many types.
FIG. 13
shows one example thereof. This wheel bearing assembly is for a driving wheel, and comprises an outer member
1
, an inner member
11
and double-row rolling elements
31
mounted between the outer member
1
and the inner member
11
.
On the inner periphery of the outer member
1
, two raceways
3
are formed while on the outer periphery thereof, a flange
2
for mounting to the vehicle body is provided.
The inner member
11
has a hub ring
12
and a raceway member
13
. A wheel-mounting flange
15
is provided on the outer periphery of the hub ring
12
at one end thereof. At the other end, a small-diameter portion
12
b
is formed on which is fitted the raceway member
13
.
On the outer peripheries of the hub ring
12
and the raceway member
13
, raceways
16
and
20
are formed, respectively. Between the raceways
16
,
20
and the raceways
3
of the outer member
1
, the rolling elements
31
are mounted.
In order to impart a pre-load to the rolling elements
31
, a spline shaft
14
c
provided on an outer joint member
14
of a constant-velocity joint is mounted into a spline hole
17
formed in the hub ring
12
, and a nut
21
is tightened on a threaded shaft
14
d
provided at the tip of the spline shaft
14
c.
The wheel bearing assembly is delivered from a wheel bearing manufacturer to an automobile assembling factory of an automotive manufacturer. At the factory, a separately delivered brake rotor
40
is fixed to one side
15
a
of the wheel-mounting flange
15
of the wheel bearing assembly by tightening bolts
42
.
After assembling, if there is a considerable run-out of the braking surfaces
40
a
of the brake rotor
40
, the frictional force will not be constant, so that vibrations and abnormal noise, so-called brake judder are produced during braking.
In order to suppress vibrations and abnormal noise produced due to run-out of the braking surfaces
40
a
of the brake rotor
40
, heretofore, increasing the machining accuracy of parts has been sought. But such a solution is time-consuming and results in higher cost.
Also, since machining errors of parts accumulate in assembling them, even if the machining accuracy of individual parts is increased, it is difficult to suppress run-out of the braking surfaces
40
a
of the brake rotor
40
.
Further, on the brake rotor-mounting surface
15
a
of the wheel-mounting flange
15
and the surface
40
b
of the brake rotor
40
that abuts the brake rotor-mounting surface
15
a
, as shown in an enlarged view of
FIG. 14A
, there exist undulations. Thus, a combination of such undulations will largely influence the run-out of the brake rotor
40
. Heretofore, at an automobile assembling factory, when the wheel-mounting flange
15
of the wheel bearing assembly and the brake rotor
40
, which are delivered as separate parts, are assembled, various adjustments including phase-adjustment at positions where run-out of the wheel-mounting flange
15
and run-out of the braking surfaces
40
a
of the brake rotor
40
are maximum and minimum have been carried out. Such a method is troublesome and poor in workability.
Also, when the brake rotor-mounting surface
15
a
of the wheel-mounting flange
15
and the surface
40
b
of the brake rotor
40
are brought into abutment with each other, due to the above said undulations, an air gap is formed therebetween. When the wheel-mounting flange
15
and the brake rotor
40
are pressed against each other in mounting the wheel, as shown by single-dot chain line in an enlarged view of
FIG. 14B
, the brake rotor
40
is liable to deform due to the air gap.
Such a deformation of the brake rotor
40
increases run out of the brake rotor
40
, thus causing brake judder.
An object of this invention is to suppress deformation of the brake rotor, thereby preventing brake judder in a simple and inexpensive manner.
SUMMARY OF THE INVENTION
According to this invention, there is provided a wheel bearing assembly comprising an outer member having two raceways on its inner periphery, an inner member having raceways on its outer periphery so as to be opposite to the raceways on the outer member, and rolling elements mounted between the raceways. One of the outer member and the inner member is formed with a wheel-mounting flange, the wheel-mounting flange having an outer face serving as a brake rotor-mounting surface. A film is disposed between the brake rotor-mounting surface of the wheel-mounting flange and an abutment surface of a brake rotor that abuts the brake rotor-mounting surface (see an enlarged view shown in FIG.
4
A). In
FIGS. 4A and 4B
, A indicates the film.
If a film is disposed between the brake rotor-mounting surface of the wheel-mounting flange and the abutment surface of the brake rotor, since it fills the air gaps which can be a factor in deformation of the brake rotor when a wheel is mounted, deformation of the brake rotor is suppressed.
While the film is formed of a material softer than steel, too soft of a material such as rubber is not preferable because it will impair the rigidity of the brake rotor and the wheel. The film may be formed by bonding or applying a sheet of an age-hardening resin or a coating of which the major component is an age-hardening resin to the brake rotor-mounting surface of the wheel-mounting flange or the abutment surface of the brake rotor that abuts the wheel-mounting flange.
The film that fills the air gaps, which can be a factor in deformation of the brake rotor, preferably has a thickness of 5 to 200 &mgr;m.
The film may be provided on one or both of the brake rotor-mounting surface of the wheel-mounting flange and the abutment surface of the brake rotor that abuts the wheel-mounting flange.
By using an age-hardening resin sheet or a coating of which the major component is an age-hardening resin as the material for the film, the mounting rigidity of the brake rotor after mounting the wheel can be assured.
Also, by using a thermosetting resin as the material for the film and providing a simple heating step on the assembly line, the mounting rigidity of the brake rotor after mounting the wheel can be assured.
According to this invention, there is also provided a wheel bearing assembly comprising an outer member having two raceways on its inner periphery, an inner member having raceways on its outer periphery so as to be opposite to the raceways on the outer member, and rolling elements mounted between the raceways, one of the outer member and the inner member being formed with a wheel-mounting flange, the wheel-mounting flange having an outer face serving as a brake rotor-mounting surface, characterized in that a plurality of hub bolts are embedded in the wheel-mounting flange and that the contact force between the wheel-mounting flange and the brake rotor when a wheel is tightened to the hub bolts is concentrated at portions near the hub bolts.
As a means for concentrating the contact force between the wheel-mounting flange and the brake rotor at portions near the hub bolts, a chamfer at an edge of each of the holes for the hub bolts formed in the brake rotor may be set to 0.5 mm or under or recesses may be formed between the hub bolts in bolt pitch circle areas on one side of the wheel-mounting flange.
By concentrating the contact force between the wheel-mounting flange and the brake rotor when a wheel is tightened to the hub bolts at portions near the hub bolts, even if there are undulating components on the brake rotor-mounting surface of the wheel-mounting flange and the surface of the brake rotor that abuts the brake rotor-mounting surface, the undulating components will not become a factor in deformation of the brake rotor. Thus it is possible to suppress deformation of the brake rotor and also the run-out of the brake rotor.
F
Fukushima Shigeaki
Tajima Eiji
Torii Akira
Butler Douglas C.
NTN Corporation
Wenderoth , Lind & Ponack, L.L.P.
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