Friction gear transmission systems or components – Friction gear includes idler engaging facing concave surfaces – Toroidal
Reexamination Certificate
2001-07-12
2003-05-13
Fenstermacher, David (Department: 3682)
Friction gear transmission systems or components
Friction gear includes idler engaging facing concave surfaces
Toroidal
C476S040000
Reexamination Certificate
active
06561946
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a toroidal-type continuously variable transmission for use as a transmission unit of an automatic transmission for an automobile or a transmission for various types of industrial machines, for example.
2. Description of the Related Art
A toroidal-type continuously variable transmission configured as shown in
FIGS. 3
to
4
has been partially used as the transmissions for automobiles. As disclosed in Japanese Utility Model Laid-Open No. 7 1465/1987, for example, such a toroidal-type continuously variable transmission is configured in a manner that an input side disk
2
as a first disk is supported concentrically with an input shaft
1
, and an output side disk
4
as a second disk is fixed to the end portion of an output shaft
3
disposed concentrically with the input shaft
1
. At the inside of a casing in which the toroidal-type continuously variable transmission is housed, there are disposed trunnions
6
,
6
swingable around pivot shafts
5
,
5
, which are disposed on an imaginary plane that is perpendicular to an imaginary line connecting the respective axes of the input and output shafts
1
,
3
, and distanced from the intersection of the imaginary plane and imaginary line, as shown in FIG.
3
. This physical relation is hereinafter referred to as “torsional relation (torsional position)”.
The base half portions of displacement shafts
8
are supported by circular holes
7
(see
FIG. 6
described later) which are formed at the intermediate portions of the trunnions
6
,
6
, respectively. The inclined angles of the displacement shafts
8
supported at the intermediate portions of the trunnions
6
,
6
are freely adjusted by swinging the respective trunnions
6
,
6
around the pivot shafts
5
,
5
, respectively. In the displacement shafts
8
which base half portions are supported by the trunnions
6
,
6
, power rollers
9
are supported rotatably at the peripheries of the tip half portions of the displacement shafts
8
protruding from the inner surfaces of the trunnions
6
,
6
, respectively. These power rollers
9
,
9
are sandwiched between the input side disk
2
and the output side disk
4
. Incidentally, the base half portions and the tip half portions of the displacement shafts
8
,
8
are eccentric to each other.
Each of opposed inner surfaces
2
a
,
4
a
of the input side disk
2
and the output side disk
4
is configured in its section as a concave surface formed by rotating an arc around the pivot shaft
5
or a curved line similar to such an arc. The peripheral surfaces
9
a
,
9
a
of the power rollers
9
,
9
each formed as a spherically convex surface abut against the inner surfaces
2
a
,
4
a
, respectively.
A pressure device
10
of a loading cam type is provided between the input shaft
1
and the input side disk
2
. Thus, the input side disk
2
is elastically pushed toward the output side disk
4
by the pressure device
10
. The pressure device
10
is configured by a cam plate
11
rotating together with the input shaft
1
and a plurality of (for example, four) rollers
13
,
13
held by a retainer
12
. A cam surface
14
forming a curved surface extending in the circumferential direction is formed on the one side surface (left side surface in
FIGS. 3 and 4
) of the cam plate
11
, and a cam surface
15
having the similar configuration as the cam surface
14
is also formed on the outer surface (right side surface in
FIGS. 3 and 4
) of the input side disk
2
. The plurality of rollers
13
,
13
are rotatably supported around the shafts extending radially with respect to the center of the input shaft
1
.
When the above-structured toroidal-type continuously variable transmission is in operation, in case where the cam plate
11
rotates in accordance with the rotation of the input shaft
1
, the plurality of the rollers
13
,
13
are pressed by the cam surface
14
to the cam surface
15
provided at the outer surface of the input side disk
2
. As a result, the input side disk
2
is pressed against the plurality of the power rollers
9
,
9
and, at the same time, the pair of the cam surfaces
14
,
15
and the rolling surfaces of the plurality of the rollers
13
,
13
are pushed to each other, whereby the input side disk
2
is rotated. The rotation of the input side disk
2
is transmitted to the output side disk
4
through the power rollers
9
,
9
to thereby rotate the output shaft
3
fixed to the output side disk
4
.
Of case where the rotation speeds of the input shaft
1
and the output shaft
3
are changed, at first, in the case of performing deceleration between the input shaft
1
and the output shaft
3
, the trunnions
6
,
6
are swung around the pivot shafts
5
,
5
. Thus, the displacement shafts
8
,
8
are inclined in such a manner that the peripheral surfaces
9
a
,
9
a
of the power rollers
9
,
9
are respectively abutted against the near-center portions of the inner surfaces
2
a
of the input side disk
2
and the near-outer-periphery portions of the inner surfaces
4
a
of the output side disk
4
, as shown in
FIG. 3
, respectively.
In contrast, in the case of performing the acceleration, the trunnions
6
,
6
are swung. And, the displacement shaft
8
,
8
are inclined in such a manner that the peripheral surfaces
9
a
,
9
a
of the power rollers
9
,
9
abut against the near-outer-periphery portions of the inner surfaces
2
a
of the input side disk
2
and the near-center portions of the inner surfaces
4
a
of the output side disk
4
, as shown in
FIG. 4
, respectively. When the inclined angles of the displacement shafts
8
,
8
are set to intermediate values between
FIGS. 3 and 4
, an intermediate transmission gear ratio can be obtained between the input shaft
1
and the output shaft
3
.
Further,
FIGS. 5 and 6
show a more specific toroidal-type continuously variable transmission disclosed in Japanese Utility Model Laid-Open No. 173552/1989. An input side disk
2
and an output side disk
4
are supported on the periphery of a cylindrical input shaft
16
through needle roller bearings
17
,
17
so as to be freely rotatable and freely movable in the axial direction of the input shaft, respectively. A cam plate
11
for constituting a pressure device of a loading cam type
10
is spline engaged with the outer peripheral surface of the end portion (left end portion in
FIG. 5
) of the input shaft
16
and is prevented by a collar portion
18
from moving in the direction away from the input side disk
2
. An output gear
19
is coupled to the output side disk
4
through keys
20
,
20
so that the output side disk
4
and the output gear
19
are rotated synchronously.
A pair of trunnions
6
,
6
are supported at their both end portions by a pair of yokes
21
,
21
so as to be freely swingable and freely movable in the axial direction (the front and rear direction in FIG.
5
and the left and right direction in FIG.
6
), respectively. The base half portions
8
a
of displacement shafts
8
are rotatably supported at circular holes
7
formed at the intermediate portions of the trunnions
6
,
6
by means of radial needle roller barings
30
, respectively. Further, power rollers
9
are rotatably supported at the peripheries of the tip half portions
8
b
of the displacement shafts
8
protruding from the inner surfaces of the trunnions
6
,
6
by means of radial needle roller bearings
31
, respectively. The base half portions
8
a
and the tip half portions
8
b
are in parallel and eccentric to each other as described above.
The pair of displacement shafts
8
,
8
correspondingly provided for the pair of trunnions
6
,
6
are provided at opposite sides by 180 degrees with respect to the input shaft
16
. The directions of the tip half portions
8
b
of the displacement shafts
8
,
8
being eccentric with respect to the base half portions
8
a
is same with respect to the rotation directions of the input side disk
2
and the output side disk
4
(left and right opposite directions in
Fenstermacher David
McAnulty Timothy
NSK Ltd.
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