Bearings – Rotary bearing – Antifriction bearing
Reexamination Certificate
2002-10-23
2004-05-04
Footland, Lenard A. (Department: 3682)
Bearings
Rotary bearing
Antifriction bearing
C384S544000
Reexamination Certificate
active
06729769
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a tire wheel bearing apparatus for use in an automobile.
2. Description of the Prior Art
FIG. 4
shows an embodiment of a tire wheel bearing apparatus used in an automobile and a structure in the case of being employed for a driven wheel. The bearing apparatus is structured such that a hub wheel
1
is rotatably supported by an axle bearing
2
, a tire wheel is fixed to the hub wheel
1
and the axle bearing
2
is supported by a suspension apparatus of a vehicle body via a knuckle
3
. The axle bearing
2
is a double-row ball-or roller bearing and is constituted by an outer wheel
6
in which double-rows of track surfaces
4
and
5
are formed on an inner diameter surface, inner wheels
9
and
10
in which track surfaces
7
and
8
are formed on an outer diameter surface, double-rows of rolling elements
11
interposed between the outer wheel
6
and the inner wheels
9
and
10
, and a retainer
12
retaining the rolling elements
11
in the respective rows at equally spaced interval in a circumferential direction. The outer wheel
6
is force fitted to the knuckle
3
and fixed by a stop ring
13
. In order to prevent foreign materials from entering into the axle bearing
2
and prevent a grease filled therewithin from leaking out, seals
14
and
15
are provided. In the illustrated example, a double-row angular ball bearing is employed as the axle bearing
2
. The hub wheel
1
is provided with a flange
16
, and hub bolts
17
for fixing the tire wheel is mounted to the flange
16
at equally spaced interval in a circumferential direction. Further, a brake rotor
18
is fixed to the flange
16
of the hub wheel
1
by the hub bolts
17
. The inner wheels
9
and
10
of the axle bearing
2
are force fitted to an outer diameter of an end portion of the hub wheel
1
, and a protruding end portion of the hub wheel
1
is fixed by a nut
19
, whereby an assembly is performed.
In the conventional tire wheel bearing apparatus mentioned above, since the outer wheel
6
of the axle bearing
2
is force fitted to the knuckle
3
having the outer non-circular profile in a strong tight manner, there is a case that the track surfaces
4
and
5
of the outer wheel
6
are deformed. Due to the deformation mentioned above, an axial run out of the bearing or the like is deteriorated, and an axial run out (or a surface run out) is generated in the brake rotor
18
mounted to the flange
16
of the hub wheel
1
after force fitted to the knuckle
3
, thereby causing a vibration at a time of braking after a high speed travel of the automobile and causing uneven wear of the brake. Further, it can be considered that a high preload is applied so as to increase a rigidity of the bearing, however, since there is a fitting portion between the hub wheel
1
and a pair of inner wheels
9
and
10
and between the outer wheel
6
and the knuckle
3
, it is unavoidable that a dispersion range of a gap reduction amount due to the preload is increased in view that the fitting tolerances are accumulated, so that the structure can not always apply a sufficient preload.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to provide a tire wheel bearing apparatus which can restrict an axial run out of a brake rotor by improving a rigidity of a bearing.
According to an embodiment of the present invention, a tire wheel bearing apparatus comprises:
an outer member having double-rows of track surfaces integrally provided on an inner periphery;
an inner member having a tire wheel mounting flange provided at one end thereof, a cylindrical small diameter step portion provided at another end thereof and double-rows of track surfaces formed by force fitting the inner wheel to the small diameter step portion so as to oppose to the track surfaces of the outer member; and
double-rows of rolling elements interposed between both of the track surfaces in the outer member and the inner member;
the inner wheel force fitted being fixed to the inner member by caulking the end portion of the small diameter step portion of the inner member radially outwardly,
wherein each of the rolling elements is installed between the track surfaces in the outer member and the inner member with contact agnle, and a bearing clearance is set to be negative.
The present invention is applicable to a structure of the type in which the track surface in the tire wheel mounting flange side among the track surfaces of the inner member is directly formed on an outer periphery of the inner member, as well.
In accordance with the present invention, the following advantages can be obtained:
(1) It is possible to so design that a span of the bearing is set to be wide within the same space and it is possible to largely improve a rigidity of the bearing.
(2) It is possible to change specifications of the inner portion within the same space, increase the number of the rolling elements so as to improve the rigidity of the bearing and optimize a thickness of the outer member and a thickness of the flange so as to restrict a deformation of the outer member, thereby improving the rigidity of the bearing.
(3) It is possible to restrict a dispersion range of an amount of a preload after being assembled to a narrow range. The higher the preload is, the higher the rigidity of the bearing is. In the tire wheel bearing apparatus in accordance with the present invention, since the number of the fitting portion is reduced, a dispersion component of the gap reduction amount due to the fitting tolerance becomes zero, so that a low preload area generated due to the accumulation of the tolerance is eliminated.
In the tire wheel bearing apparatus in accordance with the present invention, the structure can be made such that the rolling element is a ball. Further, the structure can be made such that a vehicle body mounting flange is integrally formed on an outer periphery of the outer member, the inner member is formed in a hollow shape, and an uneven engaging structure for transmitting a torque, for example, any one selected among a serration, a spline and a key is integrally provided in the inner member.
The bearing rigidity can be easily improved, and the axial run out of the brake rotor can be restricted in the case of attaching the brake rotor to the tire wheel mounting flange of the inner member. Further, in the bearing structure, since the inner wheel force fitted is fixed to the inner member by caulking the end portion of the small diameter step portion of the inner member radially outwardly, it is possible to easily realize the light weight and the compact size of the whole of the apparatus.
Further, when the structure is made such that the inner member is formed in a hollow shape, or the uneven engagement portion for transmitting the torque, for example, any one selected among the serration, the spline and the key, is integrally provided in the inner member, the tire wheel bearing apparatus in accordance with the present invention can be commonly used for the drive wheel in addition to the structure for the driven wheel. In the drive wheel side, at a time of assembling the constant velocity joint, it is not necessary to adjust the bearing clearance due to the control of the fastening torque of the nut.
Another object of the present invention is to provide a tire wheel bearing apparatus which can more restrict uneven wear of a brake rotor and a brake judder by paying attention to the other reasons for generating a surface run out of the brake rotor then an improvement of accuracy in each of the parts themselves.
According to another embodiment of the present invention, a tire wheel bearing apparatus comprises:
an outer member having double-rows of track surfaces on an inner periphery;
an inner member having track surfaces opposing to the respective track surfaces;
a bearing constituted by double-rows of rolling elements interposed between the outer member and the inner member;
the inner member and a connected member being integrally by fastening means
Hozumi Kazuhiko
Kuroda Masayuki
Niki Motoharu
Ozawa Masahiro
Sahashi Koji
Arent Fox Kintner & Plotkin & Kahn, PLLC
Footland Lenard A.
NTN Corporation
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