Friction gear transmission systems or components – Friction gear includes idler engaging facing concave surfaces – Toroidal
Reexamination Certificate
2001-03-05
2003-02-18
Lavinder, Jack (Department: 3683)
Friction gear transmission systems or components
Friction gear includes idler engaging facing concave surfaces
Toroidal
C476S046000
Reexamination Certificate
active
06520887
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a toroidal-type continuously variable transmission which is used as a transmission unit in an automatic transmission for a car or as a transmission for various kinds of industrial machines.
2. Description of the Related Art
As a transmission for a car, in some cases, there is used such a toroidal-type continuously variable transmission as shown in
FIGS. 3 and 4
. In this toroidal-type continuously variable transmission, for example, as disclosed in Japanese Unexamined Utility model Publication No. Sho. 62-71465 (JP-62-71465U), an input side disk
2
serving as a first disk is supported concentrically with an input shaft
1
and, to the end portion of an output shaft
3
which is disposed concentrically with the input shaft
1
, there is fixed an output side disk
4
which is used as a second disk. In the interior portion of a casing in which the toroidal-type continuously variable transmission is stored, there are disposed trunnions
6
,
6
which can be respectively swung about their associated pivot shafts
5
,
5
, while the pivot shafts
5
,
5
are arranged at positions which are twisted with respect to the input and output shafts
1
and
3
.
That is, each trunnion
6
includes a support plate portion
7
and, as shown in
FIG. 5
, in the two end portions of the support plate portion
7
in the longitudinal direction thereof (in
FIG. 5
, in the right and left direction), there are formed a pair of bent wall portions
8
,
8
in such a manner that they are bent toward the inner surface side (in
FIG. 5
, the lower side) of the support plate portion
7
. And, the pivot shafts
5
,
5
are respectively disposed on the outer surfaces of the bent wall portions
8
,
8
(the surfaces of the bent wall portions
8
,
8
that are present on the opposite side to the support plate portion
7
) in such a manner that the pivot shafts
5
,
5
are concentric with each other. Also, in the intermediate portion of the support plate portion
7
, there is formed a circular hole
10
which is used to support the base half portion of a shift shaft
9
to be discussed below.
In the circular hole
10
formed in the intermediate portion of the support plate portion
7
which forms each trunnion
6
having the above structure, there is supported the base half portion of the shift shaft
9
. And, by swinging the respective trunnions
6
,
6
about their associated pivot shafts
5
,
5
as a center, the inclination angles of the shift shafts
9
supported in the intermediate portions of the trunnions
6
,
6
can be adjusted. Also, on the shift shafts
9
with their respective base half portions supported in their associated trunnions
6
,
6
, specifically, on the peripheries of the leading half portions of the shift shafts
9
that are projected from the inner surfaces of the trunnions
6
,
6
, there are supported power rollers
11
in such a manner that they can be rotated. And, the power rollers
11
are held by and between the input side and output side disks
2
,
4
.
The input side and output side disks
2
,
4
respectively include inner surfaces
2
a
,
4
a
which are opposed to each other; and, the section of each of the inner surfaces
2
a
,
4
a
is formed as a concave surface which can be obtained by rotating an arc with the pivot shaft
5
as a center thereof or a curved line close to such arc. And, the peripheral surface
11
a
,
11
a
, each of which is formed as a spherically convex-shaped surface, of the power rollers
11
,
11
are contacted with the inner surfaces
2
a
,
4
a
, respectively.
Between the input shaft
1
and input side disk
2
, there is interposed a pressure device
12
of a loading cam type; and, the input side disk
2
is elastically pushed toward the outside disk
4
by the pressure device
12
. The pressure device
12
is composed of a cam plate
13
rotatable together with the input shaft
1
, and a plurality of (for example, four) rollers
15
,
15
respectively held by a retainer
14
. And, on one side surface (in
FIGS. 3 and 4
, the left side surface) of the cam plate
13
, there is formed a cam surface
16
consisting of an uneven (concave- and convex-shaped) surface which extends in the circumferential direction of the cam plate
13
; and, on the outer surface (in FIGS.
3
and
4
, the right side surface) of the input disk
2
as well, there is formed a similar cam surface
17
. Also, the plurality of rollers
15
,
15
are supported in such a manner that they can be rotated about their respective axes which extend in the radial direction with respect to the center of the input shaft
1
.
When the above-structured toroidal-type continuously variable transmission is in use, in case where the cam plate
13
is rotated as the input shaft
1
is rotated, the cam surface
16
presses the plurality of rollers
15
,
15
against the cam surface
17
formed on the outer surface of the input side disk
2
. As a result of this, not only the input side disk
2
is pressed against the plurality of power rollers
11
,
11
but also, due to mutual pressure contact between the pair of cam surface
16
,
17
and the plurality of rollers
15
,
15
, the input side disk
2
is rotated. And, the rotational movement of the input side disk
2
is transmitted through the power rollers
11
,
11
to the output side disk
4
, thereby rotating the output shaft
3
which is fixed to the output side disk
4
.
Now, the rotation speeds of the input and output shafts
1
and
3
can be changed in two manners. Firstly, to carry out deceleration between the input and output shafts
1
and
3
, the trunnions
6
,
6
may be respectively swung about their associated pivot shafts
5
,
5
to thereby incline the respective shift shafts
9
,
9
in such a manner that, as shown in
FIG. 3
, the peripheral surfaces
11
a
,
11
a
of the power rollers
11
,
11
can be respectively contacted with the near-center portion of the inner surface
2
a
of the input side disk
2
and the near-outer-periphery portion of the inner surface
4
a
of the output side disk
4
.
On the other hand, to carry out acceleration between the input and output shafts
1
and
3
, the trunnions
6
,
6
may be respectively swung about to thereby incline the respective shift shafts
9
,
9
in such a manner that, as shown in
FIG. 4
, the peripheral surfaces
11
a
,
11
a
of the power rollers
11
,
11
can be respectively contacted with the near-outer-periphery portion of the inner surface
2
a
of the input side disk
2
and the near-center portion of the inner surface
4
a
of the output side disk
4
. By the way, in case where the inclination angles of the shift shafts
9
,
9
are set between the angles shown in
FIGS. 3 and 4
, an intermediate transmission ratio can be obtained between the input and output shafts
1
and
3
.
Further,
FIGS. 6 and 7
respectively show a more specific conventional toroidal-type continuously variable transmission which is disclosed in Japanese Utility Model Unexamined publication No. Hei 1-173552 (JP-1-173552U) that is filed and stored in a microfilm. In this transmission, input side and output side disks
2
and
4
are supported respectively through their associated needle roller bearings
19
and
19
on the periphery of a circular-pipe-shaped input shaft
18
in such a manner that they can be rotated as well as can be shifted in the axial direction thereof. Also, a cam plate
13
, which is used to form a pressure device
12
of a loading cam type, is spline-engaged with the outer peripheral surface of the end portion (in
FIG. 6
, the left end portion) of the input shaft
18
; and, a collar portion
20
prevents the cam plate
13
from moving in a direction to part away from the input side disk
2
. Further, an output gear
21
is connected to the output side disk
4
by keys
22
and
22
, so that the output side disk
4
and output gear
21
can be rotated in synchronization with each other.
The two end portions of a pair of trunnions
6
and
6
, each of which has such a structure
Lavinder Jack
NSK Ltd.
Sughrue & Mion, PLLC
Sy Mariano
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