Bearings – Rotary bearing – Antifriction bearing
Reexamination Certificate
2000-04-12
2001-09-04
Fenstermacher, David (Department: 3682)
Bearings
Rotary bearing
Antifriction bearing
C384S144000
Reexamination Certificate
active
06283634
ABSTRACT:
FIELD OF THE INVENTION
The present invention is related to a transmission for automobiles and a bearing for use in the transmission.
BACKGROUND OF THE INVENTION
Generally, a rolling bearing fitted with a seal ring (referred to hereunder as a seal ring fitted rolling bearing) is incorporated for use into a transmission for automobiles, and into a rotational support section of various types of machinery such as machine tools and electrical machines.
The transmission for automobiles of the present invention is provided between an engine and a driven wheel, and is used for changing the ratio between the rotational speed of the engine crank shaft and the rotational speed of the driven wheel. Here the transmission for automobiles, which is the object of the present invention, includes as well as manual transmissions, automatic transmissions of various constructions such as planetary gear systems, belt systems, and toroidal systems.
As a transmission for automobiles incorporating a seal ring fitted rolling bearing, there is disclosed in U.S. Pat. No. 4,309,916 a construction as shown in FIG.
5
. This manual type transmission for automobiles shown in outline in
FIG. 5
has lubricating oil (transmission oil)
30
contained inside a casing
29
, and an input shaft
31
and an output shaft
32
provided concentrically and freely rotatable relative to each other inside the casing
29
. Furthermore, a transmission shaft
33
is provided inside the casing
29
, parallel with the input shaft
31
and the output shaft
32
. The input shaft
31
, output shaft
32
and transmission shaft
33
are each rotatably supported by ball bearings
1
a
with seal rings fitted therein (referred to hereunder as seal ring fitted ball bearings) for serving as rolling bearings.
Of these shafts, the input shaft
31
supports a driving side gear
34
serving as a power transmission member on the driving side. Moreover, the output shaft
32
supports by means of respective synchromesh units (not shown in the figure), driven side gears
35
a
,
35
b
,
35
c
and
35
d
serving as respective power transmission members on the driven side. At the time of operation, only one of the driven side gears
35
a
~
35
d
rotates with the output shaft
32
, the other driven side gears rotating relative to the output shaft
32
. Furthermore, the transmission shaft
33
, on the part facing the driving side gear
34
and the respective driven side gears
35
a
,
35
b
,
35
c
and
35
d
supports respective transmission gears
36
a
,
36
b
,
36
c
,
36
d
and
36
e
so as to be rotatable together with the transmission shaft
33
. The respective transmission gears
36
a
,
36
b
,
36
c
,
36
d
and
36
e
are respectively engaged with the driving side gear
34
and the driven side gears
35
a
,
35
b
,
35
c
and
35
d
either directly or via an idler gear
37
used for reversing.
In the case of the invention disclosed in the abovementioned U.S. Pat. No. 4,309,916, the respective seal ring fitted ball bearings
1
a
incorporated into the transmission for automobiles such as described above are sealed type bearings filled with grease. That is to say, for these respective seal ring fitted ball bearings
1
a
, ones constructed as shown in
FIG. 6
are used. This seal ring fitted ball bearing
1
a
comprises an outer ring
2
and an inner ring
3
disposed concentric with each other, a plurality of balls
4
serving as rolling members, a retainer
5
, and a pair of seal rings
6
a
. An outer ring raceway
7
is provided on a central portion of the inner peripheral face of the outer ring
2
, and an inner ring raceway
8
is provided on a central portion of the outer peripheral face of the inner ring
3
. The balls
4
are provided between the outer ring raceway
7
and the inner ring raceway
8
and are retained by the retainer
5
so as to be freely rotatable. Due to the rotation of the plurality of balls
4
, the outer ring
2
and the inner ring
3
are freely rotatable relative to each other.
Moreover, anchoring grooves
9
are formed on opposite end portions on the inner periphery of the outer ring
2
around the whole periphery. A pair of ring shaped seal rings
6
a
are provided the outer peripheral rim portions of which are anchored in the respective anchoring grooves
9
. The seal rings
6
a
are formed in an overall ring shape from respective ring shaped metal rings
14
and resilient material
15
such as rubber like elastomer etc. The resilient material
15
has seal lips
13
the tip edge rims of which are provided on the inner peripheral rims of the resilient material
15
to go into respective recesses
12
formed around the whole periphery of outer peripheral face portions on the opposite ends of the inner ring
3
, and come into sliding contact with a portion of these recesses
12
.
In the case of the seal ring fitted ball bearing la constructed as described above, communication between a space
16
in which the balls
4
are disposed and the outer space outside of the space
16
is shut off. Hence foreign matter existing outside cannot enter into the space
16
. Therefore, any increase in wear due to foreign matter at the contact portions between the outer ring raceway
7
and the inner ring raceway
8
and the rolling surfaces of the balls
4
is prevented, thus enabling an increase in the rolling fatigue life of the seal ring fitted ball bearing
1
a.
With the rolling bearing incorporated into a transmission for automobiles as described above for rotatably supporting the shafts
31
,
32
and
33
, prior to the invention disclosed in U.S. Pat. No. 4,309,916, a so called open type ball bearing
38
having no seal rings as shown in
FIG. 7
, was used. Lubrication of this ball bearing
38
is effected by circulation of lubricating oil
30
(
FIG. 5
) contained inside the casing
29
. However, hard foreign matter such as wear debris and shavings from the respective gears
34
,
35
a
,
35
b
,
35
c
and
35
d
,
36
a
,
36
b
,
36
c
,
36
d
and
36
e
and
37
is mixed into the lubricating oil
30
, and this foreign matter damages the outer ring raceway
7
, the inner ring raceway
8
, and the rolling surfaces of the balls
4
giving an increase in wear, so that the endurance of the ball bearing
38
is compromised. On the other hand, in the case of the above described seal ring fitted ball bearing la shown in
FIG. 6
, this foreign matter does not damage the outer ring raceway
7
, the inner ring raceway
8
and the rolling surfaces of the balls
4
, and hence the rolling fatigue life can be increased.
In the case of the seal ring fitted ball bearing
1
a
shown in
FIG. 6
, the seal rings
6
a
made up of the metal ring
14
and the resilient material
15
are used. Furthermore, lubricating grease is filled in the interior and hence cost is increased. Specifically, since the seal rings
6
a
are a tight seal having substantially no gap, it takes a substantially long time before the lubricant oil existing around the seal ring fitted ball bearing
1
a
enter the interior of the seal ring fitted ball bearing
1
a
for lubrication. Accordingly, the grease must be filled in it. In addition, when the lubricating oil
30
inside the casing
29
of the transmission for automobiles is exchanged, this grease remains unchanged. Consequently, lubrication of the seal ring fitted ball bearing
1
a
must be effected by the initially introduced grease, even though the lubricating oil
30
is exchanged several times. It is therefore necessary to use an expensive grease having a very long life, thus causing an increase in the overall cost of the seal ring fitted ball bearing
1
a
. Moreover, in the case of the seal ring fitted ball bearing
1
a
, since the seal lips
13
rub against the recesses
12
, rotational torque is increased.
In view of the above situation, the present inventors have considered using a construction such as shown in
FIG. 8
as a seal ring fitted ball bearing incorporated into the rotational support sections of various mechanical equipment such as transmissions for automobiles. In the case of the seal ring
Crowell & Moring LLP
Fenstermacher David
NSK Ltd.
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