Friction gear transmission systems or components – Friction gear includes idler engaging facing concave surfaces – Toroidal
Reexamination Certificate
2002-04-04
2003-12-09
Fenstermacher, David (Department: 3682)
Friction gear transmission systems or components
Friction gear includes idler engaging facing concave surfaces
Toroidal
Reexamination Certificate
active
06659908
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a double-cavity toroidal-type continuously variable transmission for use as a transmission for an automobile, and a method for assembling the same.
2. Description of the Related Art
An example of a double-cavity toroidal-type continuously variable transmission for use as a transmission for an automobile is disclosed in JP-A-2000-35099. The double-cavity toroidal-type continuously variable transmission is structured as shown in
FIGS. 5 and 6
. That is, an input shaft
2
is rotatably supported in the interior of a case
1
. A rotation force can be input to the input shaft
2
from a drive shaft
3
through a pressing mechanism which is constructed by a loading cam (which will be discussed later).
First and second input disks
4
,
5
are supported to the near-to-two-end-portions of the input shaft
2
through their respective ball splines
6
in such a manner that their respective inner surfaces
4
a
,
5
a
are opposed to each other. Therefore, the first and second input disks
4
,
5
are supported on the inside of the case
1
in such a manner that they are concentric with each other and can be rotated synchronously with each other. Also, the back surface of the second input disk
5
is supported by a loading nut
2
b
through a coned disk spring
2
a
and applies a pre-load to the two input disks
4
,
5
by the coned disk spring
2
a.
First and second output disks
7
,
8
are supported on the periphery of the middle portion of the input shaft
2
through a sleeve
9
. The sleeve
9
includes an output gear
10
integrally disposed on the outer peripheral surface of the middle portion thereof, and has an inside diameter larger than the outside diameter of the input shaft
2
. The sleeve
9
is supported on a gear housing
11
disposed within the case
1
by a pair of ball bearings
12
in such a manner that the sleeve
9
is concentric with the input shaft
2
and can be rotated with the input shaft
2
.
The gear housing
11
includes a pair of left and right support walls
11
a
,
11
b
and forms a ring-shaped space portion
11
c
interposed between the pair of left and right support walls
11
a
,
11
b
for enveloping the teeth portion of the output gear
10
, while the outer peripheral edge portion of the gear housing
11
is engaged by a stepped engaging portion lid. Further, a plurality of bolt holes
11
e
are formed in the stepped engaging portion
11
d
, in the transverse direction thereof (the same direction as the axial direction of the input shaft
2
) and, bolts
11
f
are inserted into these bolt holes
11
e
respectively; and, the housing
11
is fixed to the inner surface of the case
1
by these bolts
11
f.
The output gear
10
is meshingly engaged with a transmission gear
18
which is fitted with an output shaft
17
, while this transmission gear
18
is also enveloped by the gear housing
11
. Also, the gear housing
11
is fixed to a valve body
16
by a fixing member
19
.
The first and second output disks
7
,
8
are spline engaged with the two end portions of the sleeve
9
in such a manner that their respective inner surfaces
7
a
,
8
a
are directed to the mutually opposite directions. Therefore, the first input disk
4
and first output disk
7
are rotatably supported with their respective inner faces
4
a
,
7
a
opposed to each other, while the second input disk
5
and second output disk
8
are rotatably supported with their respective inner faces
5
a
,
8
a
opposed to each other.
At the positions of the inner surface of the case
1
, which are present on the lateral sides of the first and second output disks
7
,
8
, there are respectively supported an upper yoke
13
a
and a lower yoke
13
b
in such a manner that they hold the two disks
7
,
8
from both sides. The upper yoke
13
a
and lower yoke
13
b
are respectively supported on support posts
14
a
,
14
b
in such a manner that they can be shifted slightly, while the support post
14
a
is fixed to the inner surface of the case
1
by a plurality of bolts
15
. The support post
14
b
is fixed to the valve body
16
by the bolts
15
. That is, the support posts
14
a
,
14
b
are fixed in the vertical direction (a direction at right angles to the axial direction of the input shaft
2
) by the bolts
15
.
These support posts
14
a
,
14
b
are respectively disposed in a first cavity
21
, which is an intermediate portion between the inner surface
4
a
of the first input disk
4
and the inner surface
7
a
of the first output disk
7
, and in a second cavity
22
which is an intermediate portion between the inner surface
5
a
of the second input disk
5
and the inner surface
8
a
of the second output disk
8
, in such a manner that the support posts
14
a
,
14
b
are respectively disposed opposed to the first and second cavities
21
and
22
.
Therefore, in a state where the yokes
13
a
,
13
b
are supported on their respective support posts
14
a
,
14
b
, the one-end portions of the yokes
13
a
,
13
b
are opposed to the outer peripheral portion of the first cavity
21
, while the other-end portions thereof are opposed to the outer peripheral portion of the second cavity
22
.
Because the first and second cavities
21
,
22
are the same in structure, description will be given below only of the first cavity
21
. That is, a pair of trunnions
30
are disposed in the first cavity
21
. The pair of trunnions
30
are set at positions along an imaginary plane that is perpendicular to an imaginary line connecting the respective axes of the input and output disks, and distanced from the intersection of the imaginary plane and imaginary line. This physical relation is hereinafter referred to as “twisted position”. The two end portions of each of the trunnions
30
are supported on the end portions of the upper yoke
13
a
and lower yoke
13
b
in such a manner that they can be swung and can be shifted in the axial direction thereof.
Displacement shafts
31
are supported in the middle portions of the trunnions
30
, respectively. Each of the displacement shafts
31
includes a support shaft portion
33
and a pivot shaft portion
34
which are arranged parallel to and eccentric to each other. The support shaft portion
33
is supported on the trunnion
30
through a radial needle roller bearing
35
. Also, a power roller
36
is supported on the periphery of the pivot shaft portion
34
through another radial needle roller bearing
38
.
By the way, the displacement shafts
31
, which are disposed by a pair in every first and second cavities
21
,
22
, are situated on the 180° opposite side to the input shaft
2
in every first and second cavities
21
,
22
. Also, the directions, in which the pivot shaft portions
34
of the displacement shafts
31
are eccentric to their respective support shaft portions
33
, is set in the same direction with respect to the rotation direction of the first and second input disks
4
,
5
and first and second output disks
7
,
8
. Also, the eccentric direction is a direction substantially at right angles to the installation direction of the input shaft
2
. Therefore, the power roller
36
is supported in such a manner that it can be shifted slightly in the installation direction of the input shaft
2
and transmission shaft
3
. As a result of this, even in case where the power roller
36
tends to shift in the axial direction of the input shaft
2
due to variations in the elastic deformation amount of the transmission components caused by variations in torque to be transmitted by the double-cavity toroidal-type continuously variable transmission, the shifting amount of the power roller
36
can be absorbed without applying an unreasonable force to the components.
Further, a thrust ball bearing
39
and a thrust bearing
40
such as a sliding bearing or a needle roller bearing are disposed between the outer peripheral surface of the power roller
36
and the inner peripheral surface of the middle portion of the trunnion
30
in this order from the
Goto Nobuo
Imanishi Takashi
Ishikawa Kouji
Fenstermacher David
NSK Ltd.
Sughrue & Mion, PLLC
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