Friction gear transmission systems or components – Friction gear includes idler engaging facing concave surfaces – Toroidal
Reexamination Certificate
1999-06-10
2001-06-26
Estremsky, Sherry (Department: 3681)
Friction gear transmission systems or components
Friction gear includes idler engaging facing concave surfaces
Toroidal
C384S625000
Reexamination Certificate
active
06251041
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a toroidal type continuously variable transmission and, in particular, to a toroidal type continuously variable transmission for use in a vehicle or various industrial machines.
2. Description of the Related Art
Conventionally, as a toroidal type continuously variable transmission, there is known such a structure as shown in FIGS. 1 and 2 (U.S. Pat. No. 5,720,689). Here,
FIG. 1
is a side view of a basic structure of a toroidal type continuously variable transmission, showing a maximum decelerating state thereof.
FIG. 2
, similarly to
FIG. 1
, is a side view of a basic structure of a toroidal type continuously variable transmission, showing a maximum accelerating state thereof.
In the above-cited related toroidal type continuously variable transmission, an input-side disk
2
serving as a first disk is supported concentrically with an input shaft
1
. In addition, there is fixed an output-side disk
4
serving as a second disk to the end portion of an output shaft
3
disposed concentrically with the input shaft
1
. In the inside of a casing in which the toroidal type continuously variable transmission is stored, there are disposed a pair of trunnions
6
,
6
which are able to swing about their respective pivot shafts
5
,
5
respectively disposed at positions along an imaginary plane that is perpendicular to an imaginary line connecting the respective axes of the input and output shafts
1
and
3
, and distanced from the intersection of the imaginary plane and imaginary line. This physical relation is hereinafter referred to as “torsional relation”.
The pivot shafts
5
,
5
are respectively disposed on the outer side surfaces of the two end portions of the trunnions
6
,
6
. Also, the base end portions of displacement shafts
7
,
7
are respectively supported in the central portions of the trunnions
6
,
6
and, if the trunnions
6
,
6
are swung about the pivot shafts
5
,
5
respectively, the inclination angles of the displacement shafts
7
,
7
can be adjusted freely. On the peripheries of the two displacement shafts
7
,
7
supported on the two trunnions
6
,
6
, there are supported a plurality of power rollers
8
,
8
respectively in such a manner that they can be rotated freely. And, the power rollers
8
,
8
are respectively interposed between the two input- and output-side disks
2
and
4
.
The input- and output-side disks
2
and
4
respectively include inner surfaces
2
a
and
4
a
which are opposed to each other, while the sections of the mutually opposing inner surfaces
2
a
and
4
a
are formed as concave surfaces which can be obtained by rotating an arc having the pivot shaft
5
as a center thereof. And, the plurality of power rollers
8
and
8
respectively include peripheral surfaces
8
a
and
8
a
which are formed as spherical-shaped convex surfaces, while the peripheral surfaces
8
a
and
8
a
of the power rollers
8
and
8
are respectively in contact with the inner surfaces
2
a
and
4
a
of the input- and output-side disks
2
and
4
.
Between the input shaft
1
and input-side disk
2
, there is interposed a pressure device
9
of a loading cam type, while the input-side disk
2
is elastically pressed toward the output-side disk
4
by the pressure device
9
. The pressure device
9
is composed of a cam plate
10
rotatable together with the input shaft
1
, and a plurality of (for example, four pieces of) rollers
12
,
12
which are respectively held by a retainer
11
.
On one side surface (in
FIGS. 1 and 2
, on the left side surface) of the cam plate
10
, there is formed a cam surface
13
being a curved surface which extends over the circumferential direction of the cam plate
10
; and, on the outer surface (in
FIGS. 1 and 2
, on the right side surface) of the input-side disk
2
, there is also formed a similar cam surface
14
. And, the rollers
12
,
12
are supported in such a manner that they can be freely rotated about their respective shafts 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, if the cam plate
10
is rotated with the rotation of the input shaft
1
,,then the plurality of rollers
12
,
12
are pressed against the cam surface
14
on the outer surface of the input-side disk
2
by the cam surface
13
. As a result of this, the input-side disk
2
is pressed against the plurality of power rollers
8
,
8
and, at the same time, the pair of cam surfaces
13
and
14
are pressed against the plurality of rollers
12
,
12
, so that the input-side disk
2
is rotated. And, the rotation of the input-side disk
2
is transmitted through the plurality of power rollers
8
,
8
to the output-side disk
4
, so that the output shaft
3
fixed to the output-side disk
4
is rotated.
In a case of changing the rotation speed of the input and output shafts
1
and
3
, in particular, at first, when decelerating the rotation speed between the input and output shafts
1
and
3
, the trunnions
6
,
6
are respectively swung about the pivots
5
,
5
, and the displacement shafts
7
,
7
are respectively inclined so that the peripheral surfaces
8
a,
8
a
of the power rollers
8
,
8
, as shown in
FIG. 1
, can be respectively contacted with the portion of the inner surface
2
a
of the input-side disk
2
located near the center thereof and with the portion of the inner surface
4
a
of the output-side disk
4
located near the outer periphery thereof.
Also, on the other hand, when accelerating the rotation speed between the input and output shafts
1
and
3
, the trunnions
6
,
6
are respectively swung about the pivots
5
,
5
, and the displacement shafts
7
,
7
are respectively inclined so that the peripheral surfaces
8
a,
8
a
of the power rollers
8
,
8
, as shown in
FIG. 2
, can be respectively contacted with the portion of the inner surface
2
a
of the input-side disk
2
located near the outer periphery thereof and with the portion of the inner surface
4
a
of the output-side disk
4
located near the center thereof. By the way, if the inclination angle of the displacement shafts
7
,
7
is set in the middle of the inclination angles shown in
FIGS. 1 and 2
, then there can be obtained an intermediate transmission ratio between the input and output shafts
1
and
3
.
Now,
FIG. 3
shows a more specified toroidal type continuously variable transmission which is disclosed in U.S. Pat. No. 4,955,246. As shown in
FIG. 3
, an input-side disk
2
and an output-side disk
4
are rotatably supported on the periphery of a cylindrical input shaft
15
respectively through needle bearings
16
and
16
.
Also, a cam plate
10
is spline engaged with the outer peripheral surface of the end portion (in
FIG. 3
, the left end portion) of the input shaft
15
and is prevented, by a flange portion
17
, from moving in a direction away from the input-side disk
2
. Further, the cam plate
10
cooperates together with rollers
12
and
12
in forming a pressure device
9
of a loading cam type.
The pressure device
9
, in accordance with the rotation of the input shaft
15
, rotates the input-side disk
2
while it is pressing against the input-side disk
2
toward the output-side disk
4
. An output gear
18
is connected to the output-side disk
4
by keys
19
and
19
, so that the output-side disk
4
and output gear
18
can be rotated synchronously with each other.
A pair of trunnions
6
and
6
, in particular, their respective two end portions thereof are supported on a pair of support plates (not shown) in such a manner that they can be swung and can be displaced in the axial direction (in
FIG. 1
in the front and back direction) thereof. And, two displacement shafts
7
and
7
are respectively supported in circular holes (not shown) portions which are respectively formed in the middle portions of the pair of trunnions
6
and
6
. The two displacement shafts
7
and
7
respectively includ
Goto Nobuo
Higuchi Seiji
Imanishi Takashi
Ishikawa Kouji
Estremsky Sherry
Lewis Tisha D.
NSK Ltd.
Sughrue Mion Zinn Macpeak & Seas, PLLC
LandOfFree
Toroidal type continuously variable transmission does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Toroidal type continuously variable transmission, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Toroidal type continuously variable transmission will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2512444