Planetary gear transmission systems or components – Nonplanetary variable speed or direction transmission... – Nonplanetary transmission is friction gearing
Reexamination Certificate
2001-05-08
2003-02-04
Estremsky, Sherry (Department: 3681)
Planetary gear transmission systems or components
Nonplanetary variable speed or direction transmission...
Nonplanetary transmission is friction gearing
C476S010000
Reexamination Certificate
active
06514168
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a toroidal type continuous variable speed transmission utilized for a transmission unit constituting an automatic transmission utilized for a transmission unit use in automobiles, and more particularly to a toroidal type continuous variable speed transmission for reducing the driver's uncomfortable feeling by restraining variations in gear ratio attributable to trunnions and elastic deformation.
2. Description of the Related Art
A toroidal type continuous variable speed transmission, illustrated in
FIGS. 1 and 2
, to be used as an automatic transmission for automobiles is implemented in some vehicles. In this toroidal type continuous variable speed transmission, as disclosed in the Japanese Utility Model Laid-Open No. 62-71465, an input side disk
2
is supported concentrically with an input shaft
1
, and an output side disk
4
is fixed to an end of an output shaft
3
arranged concentrically with this input shaft
1
. Within a casing
5
, accommodating the toroidal type continuous variable speed transmission as shown in
FIG. 4
to be described later on, there are provided trunnions
7
, each rocking around an axis
6
. The axes
6
are in an isolated positional relationship having certain angles with the directions of the input shaft
1
and the output shaft
3
. Hereinafter in this specification, lines in an isolated positional relationship having certain angles will be referred to as skew lines.
Each of the trunnions
7
has a pair of axes
6
on the outer faces of its both ends, the axes
6
being arranged concentrically for each trunnion
7
. The central axis linking paired axes
6
does not cross the central axis of the input side disk
2
and the output side disk
4
, but is a skew line at an exactly or substantially right angle with the direction of the central axis of the input side disk
2
and the output side disk
4
. The central part of each of the trunnions
7
supports the base half of a displacement shaft
8
, whose inclination angle can be freely controlled by rocking the trunnion
7
around the axes
6
. Around the outer halves of the displacement shafts
8
, each supported by one of the trunnions
7
, power rollers
9
are supported rotatably. Each of these power rollers
9
is held between the inner face
2
a
of the input side disk
2
and the inner face
4
a
of the output side disk
4
.
Each of the mutually opposing inner faces
2
a
and
4
a
of the input side and output side disks
2
and
4
, respectively, forms a concavity having a circular section, obtained by rotating an arc or an arc-like curve centering on the axis
6
. The circumferential face
9
a
of each of the power rollers
9
, formed in a spherical convexity, is kept in contact with the inner faces
2
a
and
4
a
. Between the input shaft
1
and the input side disk
2
is provided a pressing device
10
, such as a loading cam device, and the input side disk
2
is driven rotatably while being elastically pressed by this pressing device
10
toward the output side disk
4
.
When the toroidal type continuous variable speed transmission configured as described above is used, the pressing device
10
turns the input side disk
2
while pressing it against the plurality of power rollers
9
along with the rotation of the input shaft
1
. The rotation of this input side disk
2
is transmitted to the output side disk
4
via the plurality of power rollers
9
, and the output shaft
3
fixed to this output side disk
4
turns.
To describe how the turning speeds of the input shaft
1
and the output shaft
3
are varied, first where the input shaft
1
and the output shaft
3
are to be decelerated, the trunnions
7
are rocked around the axes
6
, and each displacement shaft
8
is inclined so that the circumferential faces
9
a
of the power rollers
9
come into contact with the closer-to-the-center part of the inner face
2
a
of the input side disk
2
and the closer-to-the-periphery part of the inner face
4
a
of the output side disk
4
as shown in FIG.
1
.
Conversely, where they are to be accelerated, each of the trunnions
7
is rocked, and each displacement shaft
8
is inclined so that the circumferential faces
9
a
of the power rollers
9
come into contact with the closer-to-the-periphery part of the inner face
2
a
of the input side disk
2
and the closer-to-the-center part of the inner face
4
a
of the output side disk
4
as shown in FIG.
2
. If the angle of inclination of each displacement shaft
8
is selected between the angles shown in FIG.
1
and
FIG. 2
, an intermediate gear ratio can be obtained between the input shaft
1
and the output shaft
3
.
Further,
FIGS. 3 and 4
illustrate more specifically a toroidal type continuous variable speed transmission, described in the microfilm version of the Japanese Utility Model Application No. 63-69293 (Japanese Utility Model Laid-Open No. 1-173552). The input side disk
2
and the output side disk
4
are rotatably supported by a tubular input shaft
11
. A pressing device
10
is provided between an end part of this input shaft
11
and the input side disk
2
. On the other hand, an output gear
12
is coupled with the output side disk
4
, and they rotate in synchronism.
Axes
6
provided at two ends of a pair of trunnions
7
concentrically with each other are supported by a pair of yokes
13
rockingly and rotatably in axial directions (the direction normal to the surface of FIG.
3
and the vertical direction in FIG.
4
). A middle part of each of the trunnions
7
supports the base half of a displacement shaft
8
. The base half and the outer half of each of the displacement shafts
8
are mutually eccentric. The base half is rotatably supported by the middle part of each trunnion
7
, whose outer half rotatably supports power rollers
9
. Between the end parts of the trunnions
7
is stretched a synchronous cable
27
diagonally so that the angles of inclination of these trunnions
7
can be mechanically synchronized.
The pair of displacement shafts
8
are positioned 180 degrees reverse to the input shaft
11
. The direction in which the base half and the outer half of each of these displacement shafts
8
are eccentric is in the same direction as the turning directions of the input side and output side disks
2
and
4
(vertically reverse in FIG.
4
). The direction of eccentricity is substantially normal to the direction in which the input shaft
11
is disposed. Therefore, the power rollers
9
are supported somewhat rotatably in the direction in which the input shaft
11
is disposed.
Between the outer face of each of the power rollers
9
and the inner face of the middle part of each of the trunnions
7
are provided, from the outer face of the power roller
9
outward, a thrust ball bearing
14
and a thrust needle bearing
15
. Of these bearings, the thrust ball bearing
14
, while bearing the load working on the power rollers
9
in the thrust direction, permits these power rollers
9
to turn. Each thrust needle bearing
15
, while bearing a thrust load working from the power roller
9
on an outer race
16
constituting part of the thrust ball bearing
14
, permits the outer half of each displacement shaft
8
and the outer race
16
to rock around the base half of each displacement shaft
8
. Each of the trunnions
7
is made displaceable by a hydraulic actuator (hydraulic cylinder)
17
in the axial direction of the axis
6
.
In the toroidal type continuous variable speed transmission configured as described above, the rotation of the input shaft
11
is transmitted to the input side disk
2
via the pressing device
10
. The rotation of this input side disk
2
is further transmitted to the output side disk
4
via a pair of power rollers
9
, and the rotation of this output side disk
4
is then taken out of the output gear
12
.
When the ratio of turning speed between the input shaft
11
and the output gear
12
is to be changed, the paired trunnions
7
are displaced in mutually reverse directions wit
Estremsky Sherry
Miles & Stockbridge P.C.
NSK Ltd.
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