Friction gear transmission systems or components – Friction gear includes idler engaging facing concave surfaces – Toroidal
Reexamination Certificate
1999-09-14
2003-07-15
Joyce, William C (Department: 3682)
Friction gear transmission systems or components
Friction gear includes idler engaging facing concave surfaces
Toroidal
C476S042000, C476S046000
Reexamination Certificate
active
06592491
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
A toroidal type continuously variable transmission according to the present invention is used, for example, as a speed change unit of a transmission of a motor vehicle or transmissions of various industrial machines, respectively.
2. Related Background Art
It has been investigated that a toroidal type continuously variable transmission schematically shown in
FIGS. 24 and 25
is used as a transmission of a motor vehicle. For example, as disclosed in Japanese Utility Model Laid-Open No. 62-71465 (1987), in such a toroidal type continuously variable transmission, an input disc
2
is supported in coaxial with an input shaft
1
and an output disc
4
is secured to an end of an output shaft
3
disposed in coaxial with the input shaft
1
. Within a casing (described later in connection with
FIGS. 26
to
28
) containing the toroidal type continuously variable transmission, there are provided trunnions
7
rockable around pivot shafts
6
.located at positions twisted with respect to the input shaft
1
and the output shaft
3
.
That is to say, each trunnion
7
is provided at its both end outer surfaces with the pivot shafts
6
in coaxial with each other. Accordingly, the pivot shafts
6
do not intersect with center lines of the discs
2
,
4
but extend in perpendicular to such center lines. Further, central portions of the trunnions
7
support proximal ends of displacement shafts
8
so that inclination angles of the displacement shafts
8
can be adjusted by rocking or swinging the trunnions
7
around the pivot shafts
6
. Power rollers
9
are rotatably supported around the displacement shafts
8
supported by the trunnions
7
. The power rollers
9
are interposed between the input disc
2
and the output disc
4
. Inner surfaces
2
a
,
4
a
of the discs
2
,
4
which are opposed to each other have concave surfaces obtained by rotating arcs having centers on the pivot shaft
6
around the input shaft
1
and the output shaft
3
. Peripheral surfaces
9
a
of the power rollers
9
having spherical convex shapes abut against the inner surfaces
2
a
,
4
a
. A pressing device
10
of loading cam type is disposed between the input disc
2
and the output disc
4
so that the input disc
2
is can be urged elastically toward the output disc
4
by the pressing device
10
. The pressing device
10
comprises a cam plate
11
rotated together with the input shaft
1
, and a plurality (for example, four) of rollers
13
held by a holder
12
. One side surface (left side surface in
FIGS. 24 and 25
) of the cam plate
11
is constituted as a cam surface
14
having unevenness or undulation extending along a circumferential direction, and an outer surface (right side surface in
FIGS. 24 and 25
) of the input disc
2
has a similar cam surface
15
. The plurality of rollers
13
are rotatably supported for rotation around axes extending radially with respect to the center line of the input shaft
1
.
In use of the toroidal type continuously variable transmission having the above-mentioned construction, when the cam plate
11
is rotated as the input shaft
1
is rotated, the plurality of rollers
13
are urged against the cam surface
15
formed on the outer surface of the input disc
2
by the cam surface
14
. As a result, the input disc
2
is urged against the plurality of power rollers
9
, and, at the same time, due to the frictional engagement between the pair of cam surfaces
14
,
15
and the plurality of rollers
13
, the input disc
2
is rotated. Rotation of the input disc
2
is transmitted to the output disc
4
through the plurality of power rollers
9
, thereby rotating the output shaft
3
secured to the output disc
4
.
In a case where a rotational speed ratio (speed change ratio) between the input shaft
1
and the output shaft
3
, when deceleration is effected between the input shaft
1
and the output shaft
3
, the trunnions
7
are rocked or swung around the pivot shafts
6
in predetermined directions, thereby including the displacement shafts
8
so that the peripheral surfaces
9
a
of the power rollers
9
abut against a portion of the inner surface
2
a
of the input disc
2
near the center and a portion of the inner surface
4
a
of the output disc
4
near its outer periphery, respectively, as shown in FIG.
24
. On the other hand, when acceleration is effected, the trunnions
7
are rocked around the pivot shafts
6
in opposite directions, thereby inclining the displacement shafts
8
so that the peripheral surfaces
9
a
of the power rollers
9
abut against a portion of the inner surface
2
a
of the input disc
2
near its outer periphery and a portion of the inner surface
4
a
of the output disc
4
near the center, respectively, as shown in FIG.
25
. If the inclination angles of the displacement shafts
8
are selected to an intermediate value between FIG.
24
and
FIG. 25
, an intermediate speed change ratio can be obtained.
When the actual transmission of the motor vehicle is constituted by the above-mentioned the toroidal type continuously variable transmission, it is well known in the art to provide a so-called toroidal type continuously variable transmission of double cavity type in which two sets of input disc
2
, output disc
4
and power rollers
9
are prepared, and such two sets of input disc
2
, output disc
4
and power rollers
9
are arranged in parallel to each other along a power transmitting direction.
FIGS. 26 and 27
show an example of such a toroidal type continuously variable transmission of double cavity type disclosed in Japanese Patent Publication No. 8-23386 (1996).
An input shaft la is supported within a casing
5
for only rotation. A cylindrical transmission shaft
16
is rotatably supported around the input shaft
1
a
in coaxial with the latter for rotation relative to the input shaft
1
a.
First and second input discs
17
,
18
corresponding to first and second outer discs of the present invention are supported on both ends of the transmission shaft
16
via ball splines
19
so that inner faces
2
a
of these discs are opposed to each other. Accordingly, the first and second input discs
17
,
18
are rotatably supported within the casing
5
in coaxial with and in synchronous with each other.
Further, first and second output discs
20
,
21
corresponding to first and second inner discs of the present invention are supported around an intermediate portion of the transmission shaft
16
via a sleeve
22
. An output gear
23
is integrally formed on an outer peripheral surface of an intermediate portion of the sleeve
22
, and the sleeve has an inner diameter greater than an outer diameter of the transmission shaft
16
. The sleeve is rotatably supported by a support wall
24
provided within the casing
5
via a pair of bearings
25
in such a manner than the sleeve is disposed in coaxial with the transmission shaft
16
and can merely be rotated. In this way, the first and second output discs
20
,
21
are spline-connected to both end of the sleeve
22
rotatably mounted around the intermediate portion of the transmission shaft
16
in a condition that inner surfaces
4
a
of the discs
20
,
21
are directed toward opposite directions. Accordingly, the first and second output discs
20
,
21
are supported in coaxial with the first and second input discs
17
,
18
and are rotated independently from the first and second input discs
17
,
18
in a condition that the inner surfaces
4
a
are opposed to the respective inner surfaces
2
a
of the first and second input discs
17
,
18
.
Further, two pair of yokes
26
a
,
26
b
are supported by an inner wall of the casing
5
at both sides of the first and second output discs
20
,
21
with the interposition of these output discs
20
,
21
. The yokes
26
a
,
26
b
correspond to yokes constituting first and second supporting means of the present invention and are formed as rectangular frames, respectively, by press-working a metal plate such as a steel or forging metal material such as steel. Th
Imanishi Takashi
Ishikawa Kouji
Itoh Hiroyuki
Machida Hisashi
Yamashita Tomofumi
Joyce William C
Miles & Stockbridge P.C.
NSK Ltd.
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-3071370