Friction gear transmission systems or components – Friction gear includes idler engaging facing concave surfaces – Toroidal
Reexamination Certificate
2002-07-15
2004-10-19
Joyce, William C. (Department: 3682)
Friction gear transmission systems or components
Friction gear includes idler engaging facing concave surfaces
Toroidal
C476S008000, C476S042000
Reexamination Certificate
active
06805654
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a toroidal-type continuously variable transmission which can be used as a transmission for a vehicle.
Now,
FIG. 3
shows an example of a conventional toroidal-type continuously variable transmission which can be used as a transmission for a vehicle. This is a toroidal-type continuously variable transmission of a so-called double cavity type which is designed for high torque. In this toroidal-type continuously variable transmission, two input side disks
2
,
2
and two output side disks
3
,
3
are mounted on the outer periphery of an input shaft
1
in such a manner that they are concentric with and opposed to each other. Also, an output gear
4
is rotatably supported on the outer periphery of the middle portion of the input shaft
1
. The two output side disks
3
and
3
are respectively connected by spline engagement to cylindrical-shaped flange portions
4
a
and
4
a
formed in the central portion of the output gear
4
.
By the way, the input shaft
1
can be driven or rotated by a drive shaft
22
through a pressing device
12
of a loading cam type interposed between the input side disk
2
situated on the left side in
FIG. 3 and a
cam plate
7
. Also, the output gear
4
is supported within a housing
14
through a partition wall
13
which is composed of two members connected together, whereby the output gear
4
can be rotated about the axis O of the input shaft
1
but is prevented from shifting in the axis O direction.
The output side disks
3
and
3
are supported in such a manner that they can be rotated about the axis O of the input shaft
1
by their respective needle roller bearings
5
and
5
interposed between the input shaft
1
and disks
3
,
3
. On the other hand, the input side disks
2
and
2
are supported on the two end portions of the input shaft
1
through their respective ball splines
6
and
6
in such a manner that they can be rotated together with the input shaft
1
. Also, as shown in
FIG. 4
as well, power rollers
11
are rotatably held by and between the inner surfaces (concave surfaces)
2
a
,
2
a
of the respective input side disks
2
,
2
and the inner surfaces (concave surfaces)
3
a
,
3
a
of the respective output side disks
3
,
3
.
Between the input side disk
2
situated on the left side in FIG.
3
and cam plate
7
, there is interposed a first countersunk plate spring
8
. Between the input side disk
2
situated on the right side in FIG.
3
and loading nut
9
, there is interposed a second countersunk plate spring
10
. These countersunk plate springs
8
and
10
apply pressing forces to the mutual contact portions between the concave surfaces
2
a
,
2
a
,
3
a
,
3
a
of the respective disks
2
,
2
,
3
,
3
and the peripheral surfaces
11
a
,
11
a
(see
FIG. 4
) of the power rollers
11
,
11
.
Therefore, in the continuously variable transmission having the above structure, in case where a rotational force is input into the input shaft
1
from the drive shaft
22
, the two input side disks
2
and
2
are rotated integrally with the input shaft
1
, and the rotational movements of the input side disks
2
and
2
are transmitted by the power rollers
11
and
11
to the output side disks
3
and
3
at a given transmission ratio. Also, the rotational movements of the output side disks
3
and
3
are transmitted from the output gear
4
to an output shaft
17
through a transmission gear
15
and a transmission shaft
16
.
By the way, in the thus structured continuously variable transmission, in order to maintain the smooth sliding movements of the input side disk
2
and input shaft
1
, lubricating oil is supplied into a plurality of ball spline grooves
30
formed in the outer periphery of the input shaft
1
. Generally, this lubricating oil is allowed to flow from an oil source through oil passages
20
,
21
respectively formed in the drive shaft
22
and input shaft
1
and is supplied to the bottom portions of the ball spline grooves
30
through oil holes
1
a
formed in the input shaft
1
(see JP-A-11-182644).
Specifically, as shown in
FIGS. 5A and 5B
as well, in the center portion of the drive shaft
22
, there is formed the oil passage
20
so as to extend along the axial direction thereof; and, in the center portion of the input shaft
1
as well, there is formed the oil passage
21
which extends along the axial direction thereof so as to be able to communicate with the oil passage
20
. Also, in the two end portions of the input shaft
1
in which the ball spline grooves
30
are formed, there are formed a plurality of oil holes
1
a
which extend along the diameter direction of the input shaft
1
so as to allow the oil passage
21
and the plurality of ball spline grooves
30
to communicate with each other (see FIG.
5
B). Therefore, when the input shaft
1
is in rotation, due to the centrifugal force of the rotational movement of the input shaft
1
, the lubricating oil existing within the oil passage
21
is allowed to flow through the oil holes
1
a
to the ball spline grooves
30
, thereby being able to secure a given level of lubrication between the input shaft
1
and input side disk
2
with the ball splines
6
interposed between them.
However, in the conventional lubricating oil supply structure in which, in the input shaft
1
, there are formed the oil holes
1
a
for connecting the oil passage
21
directly to the ball spline grooves
30
, and the lubricating oil is supplied through these oil holes
1
a
to the ball spline grooves
30
directly from the oil passage
21
, there are still found several problems as follows.
Firstly, since a plurality of ball spline grooves
30
are formed in the outer periphery of the input shaft
1
at given intervals in the peripheral direction of the input shaft
1
, the same number of oil holes
1
a
as the ball spline grooves
30
must be formed along the diameter direction of the input shaft
1
in order to be able to connect together the ball spline grooves
30
and the oil passage
21
of the input shaft
1
. It takes long time to process the input shaft
1
and thus the manufacturing cost of the input shaft
1
is increased. Also, due to formation of a large number of holes in the input shaft
1
, the yield strength of the input shaft
1
is lowered.
Secondly, when the oil passage
21
and ball spline grooves
30
are directly connected together through the oil holes
1
a
, the oil holes
1
a
respectively must be formed so as to be in communication with the bottom portions of their associated ball spline grooves
30
with accuracy. That is, the oil holes
1
a
must be formed in such a manner that they are matched in position to the ball spline grooves
30
with high accuracy. However, in case where such high-accuracy working operation is enforced on the oil holes
1
a
with respect to all of the ball spline grooves
30
, there is a possibility that the working time of the input shaft
1
can be long and thus the manufacturing cost of the input shaft
1
can also be high.
SUMMARY OF THE INVENTION
The present invention aims at eliminating the drawbacks found in the above-mentioned conventional toroidal-type continuously variable transmission. Accordingly, it is an object of the present invention to provide a toroidal-type continuously variable transmission which, while employing a structure easy to process the input shaft without lowering the yield strength of the input shaft, is capable of supplying the lubricating oil to the ball spline grooves and also can be manufactured at a low cost.
In attaining the above object, according to a first aspect of the present invention, there is provided a toroidal-type continuously variable transmission, comprising: an input shaft into which a rotational force is input and including an oil passage formed in a center portion thereof so as to extend along an axial direction thereof; an input side disk rotating integrally with the input shaft; an output side disk disposed concentric with and opposed to the input side disk; a ball spline fo
Joyce William C.
NSK Ltd.
Sughrue & Mion, PLLC
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