Friction gear transmission systems or components – With lubrication
Reexamination Certificate
2002-05-22
2004-06-08
Joyce, William C. (Department: 3682)
Friction gear transmission systems or components
With lubrication
C476S040000, C476S046000
Reexamination Certificate
active
06746364
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a toroidal-type continuously variable transmission which is used in an automobile or in various kinds of industrial machines.
2. Description of the Related Art
As a transmission for an automobile, for example, there is known such a toroidal-type continuously variable transmission as shown in
FIGS. 2 and 3
.
This toroidal-type continuously variable transmission comprises an input shaft
1
, an input side disk
2
disposed coaxially with the input shaft
1
, an output shaft
3
disposed coaxially with the input shaft
1
, and an output side disk
4
fixed to the end portion of the output shaft
3
. In the interior portion of a casing in which the toroidal-type continuously variable transmission is stored, there are disposed a plurality of (in the present transmission, two) trunnions
6
,
6
which can be respectively swung about their associated pivot shafts
5
,
5
. That is, the pivot shafts
5
,
5
are respectively disposed on the outer surfaces of the two end portions of their associated trunnions
6
,
6
in such a manner that they are present in the middle portions of the input side and output side disks
2
,
4
with respect to the axial direction (in
FIGS. 2 and 3
, in the right and left direction) of the input side and output side disks
2
,
4
so as to be situated in a direction which is perpendicular to the axial direction of the two disks
2
,
4
and does not intersect the axes of the two disks
2
,
4
, that is, at positions twisted with respect to the axes of the two disks
2
,
4
(hereinafter, this physical relationship is referred to as “a twisted position”).
Also, the base end portions of displacement shafts
7
,
7
are supported on the middle portions of the respective trunnions
6
,
6
; and, in case where the trunnions
6
,
6
are swung about their associated pivot shafts
5
,
5
, the inclination angles of their associated displacement shafts
7
,
7
can be changed. Power rollers
8
,
8
are respectively supported on the respective displacement shafts
7
,
7
so as to be rotatable. These power rollers
8
,
8
are held by and between the input side and output side disks
2
,
4
. That is, the mutually opposing inner surfaces
2
a
,
4
a
of the input side and output side disks
2
,
4
are respectively formed as concave surfaces which can be obtained when arcs with their respective pivot shafts
5
,
5
as the center thereof are respectively rotated about the input shaft
1
and output shaft
3
. The peripheral surfaces
8
a
,
8
a
of the respective power rollers
8
,
8
, which are respectively formed as spherical-shaped convex surfaces, are in contact with the inner surfaces
2
a
,
4
a
of the input side and output side disks
2
,
4
.
Between the input shaft
1
and input side disk
2
, there is interposed a pressing device
9
of a loading cam type; and, the input side disk
2
is pressed toward the output side disk
4
by the pressing device
9
. The pressing device
9
includes a cam plate
10
rotatable together with the input shaft
1
and a plurality of (for example, four) rollers
12
which are respectively held by a retainer
11
. In one side surface (in
FIGS. 2 and 3
, the left side surface) of the cam plate
10
, there is formed a cam surface
13
which is a curved surface extending in the circumferential direction of the cam plate
10
; and, in the outer surface (in
FIGS. 2 and 3
, the right side surface) of the input side disk
2
as well, there is formed a cam surface
14
which is similar to the cam surface
13
. The plurality of rollers
12
are supported between the two cam surfaces
13
and
14
in such a manner that they can be rotated about their respective axes extending in the radial direction with respect to the axis of the input shaft
1
.
In the thus structured toroidal-type continuously variable transmission, in case where the cam plate
10
is rotated due to the rotation of the input shaft
1
, the cam surface
13
presses the plurality of rollers
12
against the cam surface
14
of the outer surface of the input side disk
2
. As a result of this, the input side disk
2
is pressed against the two power rollers
8
,
8
and, at the same time, due to the mutual pressing operations between the pair of cam surfaces
13
,
14
and the plurality of rollers
12
, the input side disk
2
is rotated. And, the rotational movement of the input side disk
2
is transmitted through the two power rollers
8
,
8
to the output side disk
4
, thereby rotating the output shaft
3
fixed to the output side disk
4
.
When changing the rotation speed ratio (transmission ratio) between the input shaft
1
and output shaft
3
, specifically, when reducing the transmission ratio between the input shaft
1
and output shaft
3
, the respective trunnions
6
,
6
may be swung about their associated pivot shafts
5
,
5
and, as shown in
FIG. 2
, the respective displacement shafts
7
,
7
may be inclined in such a manner that the peripheral surfaces
8
a
,
8
a
of the power rollers
8
,
8
can be respectively contacted with the near-to-center portion of the inner surface
2
a
of the input side disk
2
and the near-to-outer-periphery portion of the inner surface
4
a
of the output disk
4
.
On the other hand, when increasing the transmission ratio between the input shaft
1
and output shaft
3
, the respective trunnions
6
,
6
may be swung about their associated pivot shafts
5
,
5
and, as shown in
FIG. 3
, the respective displacement shafts
7
,
7
maybe inclined in such a manner that the peripheral surfaces
8
a
,
8
a
of the power rollers
8
,
8
can be respectively contacted with the near-to-outer-periphery portion of the inner surface
2
a
of the input side disk
2
and the near-to-center portion of the inner surface
4
a
of the output disk
4
. In case where the inclination angles of the respective displacement shafts
7
,
7
are set between the angles shown in
FIGS. 2 and 3
, there can be obtained an intermediate transmission ratio between the input shaft
1
and output shaft
3
.
Now,
FIGS. 4 and 5
show a more specific structure of a toroidal-type continuously variable transmission.
In this toroidal-type continuously variable transmission, an input side disk
2
and an output side disk
4
are respectively supported on the outer peripheral portion of an input shaft
15
through their associated needle roller bearings
16
,
16
in such a manner that they can be rotated. Also, a cam plate
10
is spline engaged with the outer peripheral surface of the end portion (in
FIG. 4
, the left end portion) of the input shaft
15
; and, a collar portion
17
prevents the cam plate
10
from moving in a direction to part away from the input side disk
2
. And, the cam plate
10
and rollers
12
,
12
cooperate together in constituting a pressing device
9
of a loading cam type which, based on the rotation of the input shaft
15
, can rotate the input side disk
2
while pressing the same toward the output side disk
4
.
To the output side disk
4
, there is connected an output gear
18
by keys
19
,
19
in such a manner that the output side disk
4
and output gear
18
can be rotated integrally. The output gear
18
and a gear (not shown) meshingly engaged with the outer gear
18
cooperate together in forming power take-out means which is used to take out the rotational power of the output side disk
4
.
Pivot shafts
5
,
5
, which are respectively disposed on the two end portions of a pair of trunnions
6
,
6
, are supported on a pair of support posts
20
,
20
in such a manner that not only they can be swung but also they can be shifted in the axial direction thereof (in
FIG. 4
, in the front and back direction; and, in
FIG. 5
, in the right and left direction). The pair of support posts
20
,
20
are respectively formed in a plate shape having sufficient rigidity and respectively include circular holes
21
,
21
formed in the central portions thereof. The circular holes
21
,
21
are fitted with the outer surfaces o
Joyce William C.
NSK Ltd.
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