Interrelated power delivery controls – including engine control – Transmission control – Continuously variable friction transmission
Reexamination Certificate
2003-04-18
2004-12-14
Lewis, Tisha D (Department: 3681)
Interrelated power delivery controls, including engine control
Transmission control
Continuously variable friction transmission
C477S050000, C477S068000
Reexamination Certificate
active
06830533
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a high-precision control for the transmission ratio of a toroidal-type continuously variable transmission disposed in a continuously variable transmission for using an automatic transmission apparatus for a vehicle.
2. Description of the Related Art
As an automatic transmission apparatus for a car, use of such a toroidal-type continuously variable transmission unit as shown in
FIGS. 13
to
15
has been studied and enforced in part of the car industry. This is referred to as a toroidal-type continuously variable transmission unit of a double cavity type, in which two input side disks
2
,
2
are respectively supported on the peripheries of the two end portions of an input shaft
1
through ball splines
3
,
3
. Therefore, the two input disks
2
,
2
are supported in such a manner that they are concentric with each other and can be rotated in synchronization with each other. Also, an output gear
4
is supported on the periphery of the middle portion of the input shaft
1
in such a manner that it can be rotated with respect to the input shaft
1
. And, two output side disks
5
,
5
are respectively spline engaged with the two end portions of a cylindrical portion formed in the central portion of the output gear
4
. Thus, the two output side disks
5
,
5
can be rotated together with the output gear
4
and in synchronization with each other.
Also, between the input side disks
2
,
2
and output side disks
5
,
5
, there are interposed and held a plurality of (normally, two or three) power rollers
6
,
6
, respectively. The power rollers
6
,
6
are rotatably supported on the inner surfaces of their associated trunnions
7
,
7
through support shafts
8
,
8
and a plurality of rolling bearings. The trunnions
7
,
7
can be swung (inclined) about and shifted with respect to pivot shafts
9
,
9
which are disposed on the longitudinal-direction (in
FIGS. 13 and 15
, the vertical direction; and, in
FIG. 14
, the front and back direction) two end portions of their associated trunnions
7
,
7
in such a manner that they are concentric with each other. The operation to incline the trunnions
7
,
7
is executed by shifting these trunnions
7
,
7
in the axial direction of the pivot shafts
9
,
9
using actuators
10
,
10
each of an oil pressure (hydraulic) type; and, the inclination angles of all of the trunnions
7
,
7
are to be synchronized with one another not only in an oil pressure manner but also in a mechanical manner.
That is, in the operation to change a transmission ratio between the input shaft
1
and output gear
4
, when changing the inclination angles of the trunnions
7
,
7
, the trunnions
7
,
7
are respectively shifted in the mutually opposite directions, using the actuators
10
,
10
; for example, the power roller
6
on the right side in
FIG. 15
is shifted to the lower side in
FIG. 15
, while the power roller
6
on the left side in
FIG. 15
is shifted to the upper side in FIG.
15
. This changes the direction of a tangential-direction force acting on the contact portions between the peripheral surfaces of the power rollers
6
,
6
and the inner surfaces of the input side and output side disks
2
,
2
,
5
,
5
(that is, a side slip phenomenon occurs in the contact portions). And, due to this change in the direction of the tangential-direction force, the trunnions
7
,
7
are respectively swung (inclined) in the mutually opposite directions about the pivot shafts
9
,
9
pivotally supported on support plates
11
,
11
. This changes the contact positions between the peripheral surfaces of the power rollers
6
,
6
and the inner surfaces of the input side and output side disks
2
,
5
, thereby changing the rotation transmission ratio between the input shaft
1
and output gear
4
.
Supply of pressure oil with respect to the actuators
10
,
10
is executed using a single transmission ratio control valve
12
regardless of the number of the actuators
10
,
10
; and, the motion of any one of the trunnions
7
is fed back to the transmission ratio control valve
12
. The transmission ratio control valve
12
includes not only a sleeve
14
to be shifted in the axial direction (in
FIG. 13
, in the front and backdirection; and, in
FIG. 15
, in the right and left direction) by a stepping motor
13
, but also a spool
15
fitted and mounted into the inside-diameter side of the sleeve
14
so as to be shiftable in the axial direction. Also, there are disposed rods
17
,
17
which are respectively used to connect the trunnions
7
,
7
to the pistons
16
,
16
of the actuators
10
,
10
; and, to the end portion of the rod
17
of any one of the trunnions
7
, there is fixed a precess cam
18
and, through the precess cam
18
and a link arm
19
, there is formed a feedback mechanism which is used to transmit the motion of the rod
17
, that is, the composite value of the axial-direction shift amount and the rotation-direction shift amount to the spool
15
. Also, between the trunnions
7
,
7
, there is provided a synchronizing cable
63
; and, the synchronous cable
63
is used to mechanically synchronize the inclination angles of the trunnions
7
,
7
with one another.
When switching the transmission condition, using the stepping motor
13
, the sleeve
14
is shifted by a given amount to thereby open the flow passage of the transmission ratio control valve
12
. As a result of this, pressure oil is fed into the actuators
10
,
10
in a given direction, so that the actuators
10
,
10
are allowed to shift the trunnions
7
,
7
in a given direction respectively. That is, as the pressure oil is fed into the actuators
10
,
10
, while the trunnions
7
,
7
are being shifted in the axial direction of their associated pivot shafts
9
,
9
, the trunnions are swung about these pivot shafts
9
,
9
respectively. And, the motion (the shifting motion in the axial direction and in the swinging direction) of any one of the trunnions
7
is transmitted to the spool
15
through the precess cam
18
fixed to the end portion of the rod
17
and through the link arm
19
, then the spool
15
is shifted in the axial direction. Due to this, in a state where the above trunnion
7
is shifted a given amount, the flow passage of the transmission ratio control valve
12
is closed to thereby stop the supply of the pressure oil to the respective actuators
10
,
10
. Therefore, the axial-direction and swinging-direction shifting amounts of the respective trunnions
7
,
7
provide the amounts that correspond to the shifting amount of the sleeve
14
caused by the stepping motor
13
.
When putting the above-structured toroidal-type continuously variable transmission unit into operation, one (in
FIGS. 13 and 14
, the left one) of the input side disks
2
is driven and rotated through such a pressing device
21
of a loading cam type or an oil pressure type as shown in
FIGS. 13 and 14
, using a drive shaft
20
connected to a power source such as an engine. As a result of this, the pair of input side disks
2
,
2
respectively supported on the two end portions of the input shaft
1
, while being pressed in their mutually approaching directions, are rotated in synchronization with each other. And, the rotational movements of the input side disks
2
,
2
are transmitted through the power rollers
6
,
6
to the output side disks
5
,
5
; and, these rotational movements are then taken out from the output gear
4
.
When the power is transmitted from the input side disks
2
,
2
to the output side disks
5
,
5
, with generation of the frictional movements in the contact portions (traction portions) between the peripheral surfaces of the power rollers
6
,
6
supported on the inner surfaces of the trunnions
7
,
7
and the inner surfaces of the respective disks
2
,
5
, to these trunnions
7
,
7
, there is applied a force which goes in the axial directions of the pivot shafts
9
,
9
respectively disposed on the two end portions of their associated trunni
Imanishi Takashi
Inoue Eiji
Toyoda Toshiro
Lewis Tisha D
NSK Ltd.
Sughrue & Mion, PLLC
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