Bearings – Rotary bearing – Antifriction bearing
Reexamination Certificate
1999-01-22
2001-03-06
Marmor, Charles A (Department: 3681)
Bearings
Rotary bearing
Antifriction bearing
C384S586000, C384S513000, C301S105100
Reexamination Certificate
active
06196727
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a rolling bearing unit used for automobiles, and more specifically, to a rolling bearing unit in which a sub-assembly article including an outer ring member, a rolling member, a retainer and a seal is in corporated into a shaft portion of an inner ring member when assembled not limiting to automobiles.
BACKGROUND OF THE INVENTION
An example of a rolling bearing unit used for an automobile or the like and heretofore known is shown in
FIGS. 3 and 5
, for example, as in U.S. Pat. No. 5,011,233. Referring to
FIG. 3
, reference numeral
30
designates a first inner ring member,
36
a second inner ring member,
38
a nut for pressing and fixing the second inner ring member
36
, and
40
an outer ring member. The first inner ring member
30
has, so that a seal
45
secured to an inner end
40
a
of the outer ring member
40
may be slidably moved, a peripheral shoulder
34
formed in an axial outer surface
33
b
of a root portion
33
a
of a radial flange
33
for fixing a wheel provided in an outer peripheral surface of an inner end
31
thereof, and a track surface
35
formed in a peripheral surface of a shaft portion
30
a
smaller in diameter than that of the peripheral shoulder
34
. The second inner ring member
36
is fitted in a step portion
48
formed in the end of the shaft portion
30
a
of the first inner ring member
30
and has a track surface
37
formed in an outer surface. The outer ring member
40
has a radial flange
39
for fixing a vehicle provided in an outer peripheral surface thereof and track surfaces
42
and
41
provided opposite to and in inner peripheral surfaces of both the track surfaces
35
and
37
of the first and second inner ring members
30
and
36
, respectively. Rolling members
43
and
44
are respectively arranged between the track surfaces
35
and
42
provided opposite to each other in the first inner ring member
30
and the outer ring member
40
, respectively, and between the track surfaces
37
and
41
provided opposite to each other in the second inner ring member
36
and the outer ring member
40
. Further, a lip
46
of a seal
45
secured to an inner end
40
a
of the outer ring member
40
to prevent a leakage of a lubricant such as grease, and prevent an entry of foreign matter such as dust and water into the bearing comprises a main lip
46
a
directed externally of the bearing and sliding on the peripheral shoulder
34
, an auxiliary lip
46
b
directed internally of the bearing and sliding on the peripheral shoulder
34
, and a side lip
46
c
sliding on the axial outer surface
33
b
of the radial flange
33
for fixing a wheel. The bearing unit has a cover
47
secured to the outer end
40
b
of the outer ring member
40
for covering the shaft end, and a retainer
48
a
for retaining the rolling members
43
and
44
. As will be apparent from the drawing, in the rolling bearing unit, a diameter D of the shaft portion
30
a
of the first inner ring member
30
is formed to have a smaller diameter than a bottom diameter D
1
of the track surface
35
. This is because of consideration that in assembly of the rolling bearing unit of this kind, when the sub-assembly including the outer ring member
40
, the rolling members
43
and
44
, the retainer
48
a
and the seal
45
is incorporated into the rolling bearing unit, the rolling members
43
and
44
are moved to the peripheral shoulder
34
and the seal
45
is installed in an adequate position.
In the case where the diameter of the shaft portion
30
a
of the first inner ring member
30
is formed to be smaller than the bottom diameter D
1
of the track surface
35
in consideration of the assembling property of the aforementioned rolling members, the rolling member
44
causes a diametral clearance between the shaft portion
30
a
and the outer ring member
40
to be large when the rolling member is not run on the track surface
35
before the sub-assembly is incorporated into the shaft portion of the first inner ring completely, as will be understood from FIG.
5
. Therefore, when the sub-assembly is further incorporated into the shaft portion so that the rolling members
43
and
44
are run on and installed on the track surfaces
37
,
35
, respectively the outer ring member sometimes greatly deviates in a diametral direction. The main lip
46
a
of the seal
45
is formed externally of the bearing as described above in consideration of preventing an entry of grease, contaminated water and the like from the outside of the bearing. As a result, when the main lip
46
a
of the seal
45
is incorporated as the sub-assembly article into the rolling bearing unit
30
a
during assembly, it is sometimes caught in a corner
34
a
(
FIG. 3
) of the peripheral shoulder
34
of the first inner ring member
30
so that the main lip
46
a
is bent backward in the direction opposite to the rolling member and installed in the peripheral shoulder
34
, posing a problem in that sealing properties between the first inner ring member
30
and the outer ring member
40
fail to be maintained.
As a means for preventing the phenomenon as described above, a rolling bearing unit as shown in
FIG. 4
is proposed. In this rolling bearing unit, a slanting surface
49
serving as a guide portion for the main lip
46
a
is formed between the peripheral shoulder
34
of the first inner ring member
30
and the track surface
35
. When the slanting surface
49
is formed between the peripheral shoulder
34
of the first inner ring member
30
and the track surface
35
as described above, it needs to be designed in a manner of that in the length of the whole rolling bearing unit, a portion of the length required for the slanting surface is extended in an axial direction. As a result, there poses a problem that the weight of the whole rolling unit increases.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a rolling bearing unit in which in an assembly operation of the rolling bearing unit, when a sub-assembly including an outer ring member, a rolling member, a retainer and a seal is incorporated into the rolling bearing unit, a main lip of the seal can be prevented from being bent backward, and the dimension of the whole unit need not to be larger.
For solving the aforementioned problem, the present invention provides a bearing unit including a peripheral shoulder formed as a sliding portion of a seal in a root portion of a radial flange provided in an outer peripheral surface of an inner end; a first inner ring member having a track surface formed in a peripheral surface of a shaft portion and having a smaller diameter than that of the peripheral shoulder; a second inner ring member fitted in an end of a shaft portion of the first inner ring member and having a track surface formed in an outer peripheral surface; a fixing member for pressing and fixing the second inner ring member; an outer ring member having a flange provided in an outer peripheral surface and track surfaces respectively formed in an inner peripheral surface opposite to both the track surfaces of the first and second inner ring members; rolling members respectively arranged between both the track surfaces of the first inner ring member and the outer ring member opposite to each other and between both the track surfaces of the second inner ring member and the outer ring member opposite to each other; and a seal pressed in and secured to an inner end of the outer ring member and having a lip sliding on the peripheral shoulder, wherein the bearing unit has a convex portion having a larger diameter than a bottom diameter of the track surface and provided at an axial outer adjacent portion of the track surface of the first inner ring member, the convex portion being capable of stranding thereon and passing therethrough the rolling member when the rolling member is incorporated into the track surface.
REFERENCES:
patent: 4786115 (1988-11-01), Ashberg
patent: 4887917 (1989-12-01), Troster et al.
patent: 4958944 (1990-09-01), Hofmann et al
Adams & Wilks
Koyo Seiko Co., Ltd
Marmor Charles A
Parekh Ankur
LandOfFree
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