Friction gear transmission systems or components – Friction gear includes idler engaging facing concave surfaces – Toroidal
Reexamination Certificate
2000-03-29
2001-12-25
Herrmann, Allan D. (Department: 3682)
Friction gear transmission systems or components
Friction gear includes idler engaging facing concave surfaces
Toroidal
C029S407010, C029S407080, C029S469000, C073S862322, C476S040000, C476S042000
Reexamination Certificate
active
06332857
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a loading cam device for a toroidal-type continuously variable transmission, an apparatus for measuring the thrust of such loading cam device, and a method for assembling a toroidal-type continuously variable transmission; and, in particular, the invention relates to a toroidal-type continuously variable transmission which is used as a change gear unit for a transmission for a vehicle, or as a transmission for various industrial machines.
Conventionally, it has been studied to use, as a transmission for a vehicle, such a toroidal-type continuously variable transmission as shown in
FIGS. 11 and 12
. In this toroidal-type continuously variable transmission, for example, as disclosed in Japanese Utility Model Publication No. Sho. 62-71465, an input side disk
2
is supported concentrically with an input shaft
1
and output disk
4
is fixed to the end portion of an output shaft
3
disposed concentrically with the input shaft
1
. In the inside portion of a casing in which the toroidal-type continuously variable transmission is stored, there are disposed trunnions
6
,
6
which are capable of swinging about their respective pivot shafts
5
,
5
situated at torsional positions which respectively lie in a direction at right angle to the direction of the input and output shafts
1
and
3
but do not intersect the axes of the input and output shafts
1
and
3
, as shown in
FIGS. 11 and 12
. That is, the trunnions
6
,
6
respectively include the pivot shafts
5
,
5
on the outer surfaces of their respective two end portions thereof in such a manner that the pivots
5
,
5
are disposed concentrically with each other. Also, on the respective intermediate portions of the trunnions
6
,
6
, there are supported the base end portions of shift shafts
7
,
7
. Accordingly, by swinging the trunnions
6
,
6
about the pivot shafts
5
,
5
, the inclination angles of the shift shafts
7
,
7
can be freely adjusted. On the respective peripheries of the shift shafts
7
,
7
which are supported on the trunnions
6
,
6
, there are rotatably supported power rollers
8
,
8
. And, the power rollers
8
,
8
are respectively held by and between the mutually opposing inner surfaces
2
a
,
4
a
of the input side and output side disks
2
,
4
. The sections of the inner surfaces
2
a
,
4
a
are respectively formed in a concave-shaped surface which can be obtained by rotating an arc about the pivot shaft
5
. And, the peripheral surfaces
8
a
,
8
a
of the power rollers
8
,
8
, which are respectively formed in a spherically convex-shaped surface, are respectively contacted with the inner surfaces
2
a
,
4
a.
Between the input shaft
1
and input side disk
2
, there is interposed a loading cam device
9
. While the input side disk
2
is being elastically pressed toward the output side disk
2
by the loading cam device
9
, the input side disk
2
can be freely rotated. The loading cam device
9
includes a cam plate
10
which can be rotated together with the input shaft
1
, and a plurality of (for example, four) rollers
12
,
12
which are rollably held by a retainer
11
. On one side surface (in
FIGS. 11 and 12
, on the left side surface) of the cam plate
10
, there is formed a drive side cam surface
13
which is an uneven surface extending in the circumferential direction of the cam plate
10
; and, on the outer surface (in
FIGS. 11 and 12
, on the right side surface) of the input side disk
2
, there is formed a driven side cam surface
14
having a similar shape to the drive side cam surface
13
. And, the plurality of rollers
12
,
12
are supported in such a manner that they can be freely rotated about their respective shafts extending 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 operation, in case where the cam plate
10
is rotated with the rotation of the input shaft
1
, the drive side cam surface
13
presses the plurality of rollers
12
,
12
against the driven side cam surface
14
formed on the outer surface of the input side disk
2
. As a result of this, at the same time when the input side disk
2
is pressed by the plurality of rollers
12
,
12
, the input side disk
2
is rotated due to the mutual pressing movements between the drive and driven side cam surfaces
13
,
14
and the plurality of rollers
12
,
12
. 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
can be rotated.
To change a rotation speed ratio (change gear ratio) between the input and output shafts
1
and
3
, firstly, when carrying out deceleration between the input and output shafts
1
and
3
, the trunnions
6
,
6
may be swung in a given direction about their respective pivot shafts
5
,
5
. And, the shift shafts
7
,
7
may be inclined in such a manner that the peripheral surfaces
8
a
,
8
a
of the power rollers
8
,
8
, as shown in
FIG. 11
, can be respectively contacted with the near-to-center portion of the inner surface
2
a
of the input side disk
2
and the near-to-outer-periphery portion of the inner surface
4
a
of the output side disk
4
. On the other hand, for acceleration, the trunnions
6
,
6
may be swung in the opposite direction about their respective pivot shafts
5
,
5
. And, the shift shafts
7
,
7
may be inclined in such a manner that the peripheral surfaces
8
a
,
8
a
of the power rollers
8
,
8
, as shown in
FIG. 12
, can be respectively contacted with the near-to-outer-periphery portion of the inner surface
2
a
of the input side disk
2
and the near-to-center portion of the inner surface
4
a
of the output side disk
4
. In case where the inclination angles of the shift shafts
7
,
7
are set in the intermediate angle between the inclination angles respectively shown in
FIGS. 11 and 12
, an intermediate change gear ratio can be obtained between the input and output shafts
1
and
3
.
Also,
FIGS. 13 and 14
show a more concrete example of a toroidal-type continuously variable transmission which is disclosed in Japanese Utility Model Publication No. Hei. 1-173552. An input side disk
2
and an output side disk
4
are rotatably supported on the periphery of a circular-pipe-shaped input shaft
15
respectively through needle roller bearings
16
,
16
. Also, a cam plate
10
is spline engaged with the outer peripheral surface of the end portion (in
FIG. 13
, the left end portion) of the input shaft
15
, while a flange portion
17
prevents the cam plate
10
from moving in a direction to go away from the input side disk
2
. And, the cam plate
10
and rollers
12
,
12
cooperate together in forming a loading cam device
9
of a loading cam type which, in accordance with the rotation of the input shaft
15
, rotates the input side disk
2
while pressing against the input side disk
2
toward the output side disk
4
. To the output side disk
4
, there is connected an output gear
18
through keys
19
,
19
in such a manner that the output side disk
2
and output gear
18
are allowed to rotate synchronously with each other.
The respective two end portions of the pair of trunnions
6
,
6
are supported on a pair of support plates
20
,
20
in such a manner that they can be swung as well as can be shifted in the axial direction (in
FIG. 13
, in the front and back direction; in,
FIG. 14
, in the right and left direction) thereof. And, on circular holes
23
,
23
portions which are respectively formed in the intermediate portions of the trunnions
6
,
6
, there are supported shift shafts
7
,
7
, respectively. And, these shift shafts
7
,
7
respectively include support shaft portions
21
,
21
and pivot sat portions
22
,
22
which extend in parallel to each other but are eccentric with each other. Of these portions, the support shaft portions
21
,
21
are respectively supported inwardly of their associ
Hirata Kiyotaka
Ishikawa Kouji
Kumagae Mitsuo
Herrmann Allan D.
NSK Ltd.
Sughrue & Mion, PLLC
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