Starting clutch controls for continuous variable transmissions

Details Starting clutch controls for continuous variable transmissions Starting clutch controls for continuous variable transmissions

2000-10-11

2002-06-11

Marmor, Charles A (Department: 3681)

Interrelated power delivery controls, including engine control

Transmission control

Continuously variable friction transmission

Reexamination Certificate

active

06402659

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a starting clutch control system for a continuous variable transmission to regulate an engaging pressure in a starting clutch, which is placed behind the toroidal continuously-variable transmission.
2. Description of the Prior Art
Among the conventional continuous variable transmissions is known a toroidal continuously-variable transmission having either only one or at least two toroidal transmission units arranged along the common centerline, each of which is comprised of an input disk driven by an input shaft, an output disk arranged in opposition to the input disk and connected to an output shaft, and power rollers coming into frictional rolling-contact with both the input and output disks. In the toroidal continuously-variable transmissions constructed as described above, the torque transmitted to the output disks is available for the output shaft through a power train composed of a chain gearing, countershaft and output geared wheel.
Referring now to
FIG. 4
, there is shown a conventional toroidal continuously-variable transmission having incorporated with a starting clutch control system. The toroidal continuously-variable transmission in
FIG. 4
is of a double-cavity construction including first and second toroidal transmission units
1
,
2
arranged in series on a common centerline of a main shaft
3
. The first toroidal transmission unit
1
is comprised of an input disk
4
, an output disk
5
arranged confronting the input disk
4
, and a pair of power rollers
6
disposed between the confronting disks
4
,
5
with coming in frictional rolling-engagement with toroidal surfaces of the disks
4
,
5
. The second toroidal transmission unit
2
is constructed in the same manner as the first toroidal transmission unit
1
, and comprised of an input disk
7
, an output disk
8
arranged in opposition to the input disk
7
, and a pair of power rollers
9
disposed between the confronting disks
7
,
8
with coming in frictional rolling-engagement with toroidal surfaces of the disks
7
,
8
. The power rollers
6
,
9
are each for rotation on its own rotating axis
10
and also supported for pivoting motion about its associated pivotal axis
11
that is normal to the rotating axis
10
or normal to the plane surface of this paper.
The power from the engine is applied to the main shaft
3
through a hydraulically actuated loader
12
. The input disk
4
turning in unison with the main shaft
3
acts as a piston of the hydraulically actuated loader
12
for pressing the power rollers
6
of the first toroidal transmission unit
1
, depending on the magnitude of hydraulic pressure exerted by the hydraulically actuated loader
12
, and also causes the reaction where a cylinder of the hydraulically actuated loader
12
thrusts the input disk
7
in the second toroidal transmission unit
2
, which turns together as an unit with the main shaft
3
, against the power rollers
9
through the main shaft
3
. Thus, the main shaft
3
serves the input shafts to both the input disks
4
,
7
. The thrust force exerted by the hydraulically actuated loader
12
squeezes the power rollers
6
,
9
between the paired confronting input and output disks
4
,
7
and
5
,
8
to provide the frictional traction force depending on the magnitude of the transmitted torque.
The rotation of the input disks
4
,
7
in the toroidal transmission units
1
,
2
is transmitted with infinitely variable gear ratios or speed ratios to the output disks
5
,
8
by virtue of the power rollers
6
,
9
that may pivot about their pivotal axes
11
. The power roller
6
,
9
are supported on trunnions, shown at
35
in
FIG. 5
, for rotating and pivoting motions so as to deal with the axial movement of the main shaft
3
, which might occur due to the thrust force exerted by the loader.
In neutral position where the rotating axes
10
of the power rollers
6
,
9
intersect with the axis of the main shaft
3
, the speed ratio is kept at a value that is in compliance with any pivotal angle of the power rollers
6
,
9
. If the trunnions are moved together with the power rollers
6
,
9
along the axial direction of the pivotal axes
11
during torque transmission, the rolling-contact areas of the power rollers
6
,
9
with the input and output disks
4
,
7
and
5
,
8
deviate from the contact areas at the neutral position. As a result, the power rollers
6
,
9
experience the pivoting forces exerted by the disks
4
,
7
and
5
,
8
so as to pivot on their pivotal axes
11
with the direction and velocity, which depend on the direction and amount of their displacements along the pivotal axes
11
. This pivoting motion of the power rollers
6
,
9
causes the variations in the ratio between a radius defined by loci of the rolling-contact locations of the power rollers with the input disks
4
,
7
and another radius defined by loci of the rolling-contact locations of the power rollers with the output disks
5
,
8
whereby the speed ratio may be changed in a continuously variable manner. A controller unit, shown at
47
in
FIG. 5
, governs the operation of a hydraulic actuator, shown at
36
in
FIG. 5
, to regulate the displacements of the trunnions along the its pivotal axes thereby making the power rollers
6
,
9
pivot so as to attain the desired speed ratio.
The output disks
5
,
8
are arranged back to back and connected to the connecting shaft
16
through the spline fit or the like to turn together as an unit. The connecting shaft
16
is of a hollow tube in which the main shaft
3
is fitted for rotation relatively to each other. The output disks
5
,
8
are supported at the connecting shaft
16
on a casing
22
through bearings, not shown, which may bear both the thrust and radial loads. The torque transmitted to the output disks
5
,
8
is applied through a chain gearing
17
to a countershaft
28
arranged in parallel with the main shaft
3
. The chain gearing
17
is composed of a sprocket wheel
18
mounted integrally midway the connecting shaft
16
, a sprocket wheel
24
supported integrally on one end of the countershaft
28
, and an endless chain
26
wound around the sprocket wheels
18
,
19
.
The countershaft
21
has on its opposite end an output gear wheel
23
, which is in turn meshed with a gear wheel
26
formed around a carrier
25
that is supported for rotation on an output shaft
24
. The carrier
25
is allowed to come into engagement with the output shaft
24
through a starting clutch
27
. A high-range clutch
28
is arranged on the main shaft
3
at the end axially opposite to the hydraulically actuated loader
12
with respect to the toroidal transmission units, while a reverse brake
29
is disposed between the output side of the high-range clutch
28
and the casing
22
. The high-range clutch
28
is drivingly connected at its output side with the output shaft
24
through a double-pinion planetary gearset
30
, which is comprised of a ring gear
31
formed integrally to the output side of the high-range clutch
28
, a sun gear
32
made integral with the output shaft
24
, and two pinions
33
,
34
supported for rotation on the carrier
25
and Juxtaposed radially between the ring gear
31
and the sun gear
32
in mesh with one another.
The following explains the operation of the toroidal continuously-variable transmission constructed as described just above. To get the vehicle starting to move, the starting clutch
27
is engaged in such a manner that the coupling pressure rises gradually from a low level where the clutch slips momentarily while engaging to a high level where the engagement is completed with all slipping having stopped. Both the high-range clutch
28
and the reverse brake
29
remain still disengaged. Thus, the power train is established in which the torque of the engine flows through the main shaft
3
, toroidal transmission units
1
,
2
: the input disks
4
,
7
, power rollers
6
,
9
and output disks
5
,
8
, and further flowing through the conn

Affiliated with

Also associated with

Rating

Starting clutch controls for continuous variable transmissions does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Starting clutch controls for continuous variable transmissions, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Starting clutch controls for continuous variable transmissions will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2929386