Friction gear transmission systems or components – Friction gear includes idler engaging facing concave surfaces – Toroidal
Reexamination Certificate
2000-08-08
2002-12-17
Joyce, William C (Department: 3682)
Friction gear transmission systems or components
Friction gear includes idler engaging facing concave surfaces
Toroidal
C476S040000
Reexamination Certificate
active
06494807
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a half-toroidal-type continuously variable transmission which can be used, for example, as a transmission unit for a car transmission or a transmission for various kinds of industrial machines. Especially, the invention relates to a trunnion to be incorporated into such half-toroidal-type continuously variable transmission, and a method for working such trunnion with ease.
2. Description of the Related Art
Conventionally, it has been studied to use such a half-toroidal-type continuously variable transmission as schematically shown in
FIGS. 7 and 8
, for example, as a transmission unit for a car transmission. In the conventional half-toroidal-type continuously variable transmission, for example, as disclosed in JP-A-62-71465U, an input side disk
2
is supported concentrically with an input shaft
1
, while an output side disk
4
is fixed to the end portion of an output shaft
3
disposed concentrically with the input shaft
1
. In the interior portion of a casing in which the half-toroidal-type continuously variable transmission is stored, there are disposed trunnions
6
,
6
swingable about their respective pivot shafts
5
,
5
which are set at torsional positions with respect to the input and output shafts
1
and
3
. That is, the center axes of the pivot shafts
5
,
5
do not intersect with the center axes of the input and output shafts
1
and
3
but they are respectively present in the directions that are perpendicular to the directions of the center axes of the input and output shafts
1
and
3
.
In the trunnions
6
,
6
, the pivot shafts
5
,
5
are arranged on the outer surfaces of the two end portions thereof in such a manner that they are concentric with each other. The base end portions of displacement shafts
7
,
7
are supported on the respective central portions of the trunnions
6
,
6
and, by swinging the trunnions
6
,
6
about their respective pivot shafts
5
,
5
, the inclination angles of the displacement shafts
7
,
7
can be freely adjusted. On the peripheries of the displacement shafts
7
,
7
respectively supported on the trunnions
6
,
6
, there are rotatably supported a plurality of power rollers
8
,
8
. And, the plurality of power rollers
8
,
8
are respectively held by and between the input side and output side disks
2
,
4
. The two disks
2
,
4
respectively include inner surfaces
2
a
,
4
a
which are disposed such that they are opposed to each other. The mutually opposed inner surfaces
2
a
,
4
a
each have a cross section formed as a concave surface which can be obtained by rotating an arc with the pivot shaft
5
as the center thereof. On the other hand, the power rollers
8
,
8
respectively have peripheral surfaces
8
a
,
8
a
each of which is formed as a spherically convex surface. And, the peripheral surfaces
8
a
,
8
a
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 pressure device
9
such as a loading cam. Thus, the input side disk
2
can be elastically pushed toward the output side disk
4
by the pressure device
9
. The pressure device
9
comprises a cam plate
10
rotatable together with the input shaft
1
, and a plurality of rollers
12
,
12
(for example, four rollers) which are respectively held by a retainer
11
. On one side surface (in
FIGS. 7 and 8
, the left side surface) of the cam plate
10
, there is formed a cam surface
13
which consists of a curved surface extending in the circumferential direction of the cam plate
10
; and, on the outer surface (in
FIGS. 7 and 8
, the right side surface) of the input side disk
2
as well, there is formed a cam surface
14
which is similar to the cam surface
13
. And, the plurality of rollers
12
,
12
are rotatably supported about their respective axes extending in the radial direction with respect to the center of the input shaft
1
.
When the above-structured half-toroidal-type continuously variable transmission is in operation, in case where the cam plate
10
is rotated due to the rotation of the input shaft
1
, the plurality of rollers
12
,
12
are respectively pressed against the cam surface
14
formed on the outer surface of the input side disk
2
by the cam surface
13
of the cam plate
10
. 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
,
14
and the plurality of rollers
12
,
12
are pressed against each other, thereby causing the input side disk
2
to be rotated. And, the rotation of the input side disk
2
is transmitted to the output side disk
4
through the plurality of power rollers
8
,
8
, with the result that the output shaft
3
fixed to the output side disk
4
can be rotated.
Of cases in which the rotation speed between the input shaft
1
and output shaft
3
is to be changed, at first, in case where deceleration is carried out between the input shaft
1
and output shaft
3
, the trunnions
6
,
6
are swung about their respective pivot shafts
5
,
5
, and the displacement shafts
7
,
7
are inclined in such a manner that the peripheral surfaces
8
a
,
8
a
of the power rollers
8
,
8
, as shown in
FIG. 7
, can be respectively contacted with the near-center portion of the inner surface
2
a
of the input side disk
2
and with the near-outer-periphery portion of the inner surface
4
a
of the output side disk
4
. On the other hand, in the case of acceleration, the trunnions
6
,
6
are swung about their respective pivot shafts
5
,
5
, and the displacement shafts
7
,
7
are inclined in such a manner that the peripheral surfaces
8
a
,
8
a
of the power rollers
8
,
8
, as shown in
FIG. 8
, can be respectively contacted with the near-outer-periphery portion of the inner surface
2
a
of the input side disk
2
and with the near-center portion of the inner surface
4
a
of the output side disk
4
. In case where the inclination angles of the displacement shafts
7
,
7
are set in the middle of the inclination angles in
FIGS. 7 and 8
, there can be obtained a middle transmission ratio.
The specific shapes of the trunnions
6
,
6
as well as the structures of portions for supporting the power rollers
8
,
8
on the trunnions
6
,
6
are conventionally known; that is, they are disclosed, for example, in JP-A-8-240251. Now,
FIGS. 9
to
11
shows a conventional structure of a portion for supporting the power roller
8
on the trunnion
6
. In the middle portion of the trunnion
6
, there is formed a circular hole
15
. The circular hole
15
is formed in a direction perpendicular to the pivot shafts
5
,
5
respectively disposed on the two end portions of the trunnion
6
(that is, in a direction where the extensions of the center axes of the pivot shafts
5
,
5
and the extension of the center axis of the circular hole
15
are perpendicular to each other). And, on the portion of the trunnion
6
that is present inside the circular hole
15
, there is supported the displacement shaft
7
. The displacement shaft
7
includes a support shaft portion
16
and a pivot shaft portion
17
which are arranged in parallel to each other but are offset from each other in the axes thereof. Of these two portions of the displacement shaft
7
, the support shaft portion
16
is rotatably supported inside the circular hole
5
through a radial needle roller bearing
18
. Also, on the periphery of the pivot shaft portion
17
, there is rotatably supported the power roller
8
through another radial needle roller bearing
19
.
Also, between the outer surface of the power roller
8
and the inner surface of the middle portion of the trunnion
6
, there are interposed a thrust ball bearing
20
and a thrust needle roller bearing
21
in order starting from the outer surface of the power roller
8
. Of these two bearings, the thrust ball bearing
20
, while supporting a thrust load applied to the power roller
8
, allows the power r
Horike Shoji
Iwasawa Takaji
Kamamura Yuko
Joyce William C
NSK Ltd.
Sughrue & Mion, PLLC
LandOfFree
Trunnion for half-toroidal-type continuously variable... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Trunnion for half-toroidal-type continuously variable..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Trunnion for half-toroidal-type continuously variable... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2964785