Metal working – Method of mechanical manufacture – Shaping one-piece blank by removing material
Reexamination Certificate
2000-08-04
2002-04-23
Hughes, S. Thomas (Department: 3726)
Metal working
Method of mechanical manufacture
Shaping one-piece blank by removing material
C148S579000, C148S597000, C148S598000
Reexamination Certificate
active
06374477
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an improved method for working an input shaft constructing a part of a toroidal-type continuously variable transmission which is used, for example, as a car transmission; and, in the improved method, the incidence of defective products caused when working input shafts is restrained to thereby be able to enhance the yield rate of the input shaft and thus reduce the cost of the input shaft as well as the cost of the toroidal-type continuously variable transmission.
Conventionally, it has been studied to use such a toroidal-type continuously variable transmission as shown in
FIGS. 2 and 3
as a transmission unit for a vehicle. This is generally referred to as a half-toroidal-type continuously variable 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, in more particular, at the axial-direction middle positions of the input side and output side disks
2
,
4
, there are disposed trunnions
6
,
6
. These trunnions
6
,
6
are respectively oscillatable about their associated pair of pivot shafts
5
,
5
which are set at torsional positions with respect to the input and output shafts
1
and
3
, that is, at positions that are-perpendicular to the axial direction (in
FIGS. 2 and 3
, in the tight and left direction) of the input and output shafts
1
and
3
and do not intersect the center axes of the input and output shafts
1
and
3
.
That is, in the case of the trunnions
6
,
6
, the pivot shafts
5
,
5
are arranged on the outer surfaces of the two end portions of the trunnions
6
,
6
in such a manner that the pivot shafts
5
,
5
are concentric with each other. The base end portions of displacement shafts
7
,
7
are supported on the respective middle portions of the trunnions
6
,
6
and, by oscillating 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 mutually opposed inner surfaces
2
a,
4
a
of the input side and output side disks
2
,
4
. The mutually opposing 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 rollably held by a retainer
11
. On one side surface (in
FIGS. 2 and 3
, the right side surface) of the cam plate
10
, there is formed a cam surface
13
constructing a curved surface extending in the circumferential direction of the cam plate
10
; and, on the outer surface (in
FIGS. 2 and 3
, the left side surface) of the input side disk
2
as well, there is formed a cam surface
14
which is similar in shape to the 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 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 ratio (transmission ratio) between the input shaft
1
and output shaft
3
is to be changed, at first, when decreasing the rotation speed ratio between the input shaft
1
and output shaft
3
, the trunnions
6
,
6
may be swung about their respective pivot shafts
5
,
5
in a given direction. 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. 2
, 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, when increasing the rotation speed ratio, the trunnions
6
,
6
may be swung about their respective pivot shafts
5
,
5
, in the opposite direction. 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. 3
, 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. 2 and 3
, there can be obtained a middle rotation speed ratio between the input shaft
1
and output shaft
3
.
Now,
FIGS. 4 and 5
show an example of a more specific structure of a toroidal-type continuously variable transmission which is disclosed in JP-A-1-173552U. In this structure, an input side disk
2
and an output side disk
4
are rotatably supported on the peripheries of a circular-pipe-shaped input shaft
15
through their respective needle roller bearings
16
,
16
. In the case of the input shaft
15
, as can be seen clearly from
FIG. 6
in which, of the component members of the toroidal-type continuously variable transmission, only the input shaft
15
is shown, at a plurality of positions in the middle portion of the input shaft
15
in the axial direction (in
FIGS. 4 and 6
, in the right and left direction) thereof, there are formed through holes
17
,
17
which respectively allow the two inner and outer peripheral surfaces of the input shaft
15
to communicate with each other. When the toroidal-type continuously variable transmission is in operation, lubricating oil (traction oil), which has been supplied into the interior portion of the input shaft
15
from oil supply means such as an oil supply pump (not shown), is discharged externally of the input shaft
15
through the through holes
17
,
17
to thereby lubricate movable portions existing in the periphery of the input shaft
15
, such as the needle roller bearings
16
,
16
.
Also, a camplate
10
is spline engaged with the outer peripheral surface of the end portion (in
FI
Hashitani Hideki
Tanaka Masami
Hughes S. Thomas
NSK Ltd.
Omgba Essama
Sughrue & Mion, PLLC
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