Friction gear transmission systems or components – Friction transmission or element – Particular friction surface
Reexamination Certificate
2002-01-22
2003-09-30
Fenstermacher, David (Department: 3682)
Friction gear transmission systems or components
Friction transmission or element
Particular friction surface
C384S606000, C384S614000
Reexamination Certificate
active
06626795
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a toroidal-type continuously variable transmission and, for example, to a toroidal-type continuously variable transmission for use in a vehicle such as a car.
Conventionally, as a toroidal-type continuously variable transmission, for example, there is known a transmission which has such a structure as shown in FIG.
1
.
Specifically, in the interior of a housing (not shown), an input disk
1
and an output disk
2
are disposed in such a manner that they are concentric with each other but are opposed to each other. An input shaft
3
is penetrated through the axial core portion of a toroidal transmission part in which the input disk
1
and output disk
2
are disposed. On one end of the input shaft
3
, there is disposed a loading cam
4
. This loading cam
4
is structured such that it can transmit the power (rotational force) of the input shaft
3
to the input disk
1
through a cam roller
5
.
Also, between the input disk
1
and output disk
2
, there are interposed a plurality of trunnions swingable about their respective support shafts (not shown) disposed at positions twisted with respect to the center axes of the two disks
1
and
2
(in other words, between the input disk
1
and output disk
2
, there are interposed a plurality of trunnions swingable about their respective support shafts (not shown) each of which is disposed at a positions that is perpendicular to an axial line of the input shaft
3
and does not intersect the axial line thereof (this physical relationship is referred as “a twisted position”.).
The input disk
1
and output disk
2
are substantially the same in shape and are also arranged symmetric, while their respective opposed surfaces are respectively formed as toroidal surfaces which, when they are viewed in the axial-direction section thereof, cooperate together in forming a substantially semicircular shape. Within a toroidal cavity defined by the toroidal surfaces of the input disk
1
and output disk
2
, a pair of power roller bearings
6
and
7
are disposed for power transmission in such a manner that they are in contact with the input disk
1
and output disk
2
.
By the way, the power roller bearing
6
comprises a power roller
6
a
(which corresponds to an inner ring forming the power roller bearing
6
) capable of rolling on the toroidal surfaces of the input disk
1
and output disk
2
, an outer ring
6
b
, and a plurality of rolling elements (steel balls)
6
c
. On the other hand, the other power roller bearing
7
comprises a power roller
7
a
(which corresponds to an inner ring forming the power roller bearing
7
) capable of rolling on the toroidal surfaces of the input disk
1
and output disk
2
, an outer ring
7
b
, and a plurality of rolling elements (steel balls)
7
c.
That is, the power roller
6
a
serves also as the inner ring which is a component of the power roller bearing
6
, and the power roller
7
a
serves also as the inner ring which is a component of the power roller bearing
7
. In this structure, the power roller
6
a
is mounted pivotally and rotatably on a trunnion
10
through a pivot shaft
8
, the outer ring
6
b
and the plurality of rolling elements
6
c
, and also is supported so as to be inclinable about a shift shaft
0
which provides the center of the toroidal surfaces of the input disk
1
and output disk
2
.
On the other hand, the power roller
7
a
is mounted pivotally and rotatably on a trunnion
11
through a pivot shaft
9
, the outer ring
7
b
and the plurality of rolling elements
7
c
, and also is supported so as to be inclinable about a shift shaft
0
which provides the center of the toroidal surfaces of the input disk
1
and output disk
2
. And, lubricating oil (traction oil) having large viscous frictional resistance is supplied to the contact surfaces of the input disk
1
and output disk
2
with respect to the power roller
6
a
and power roller
7
a
, in such a manner that the power input to the input disk
1
can be transmitted to the output disk
2
through the film of the lubricating oil, power roller
6
a
and power roller
7
a.
By the way, the input disk
1
and output disk
2
are connected with the input shaft
3
through needle roller bearings
12
such that they are independent of the input shaft
3
(that is, they are held in a state where they are not influenced directly by the power of the input shaft
3
). On the output disk
2
, there is disposed an output shaft
14
which is arranged in parallel to the input shaft
3
and also supported rotatably on the housing (not shown) through angular contact ball bearings
13
.
In the toroidal-type continuously variable transmission
20
, the power of the input shaft
3
is transmitted to the loading cam
4
. In case where the loading cam
4
is rotated due to this power transmission, power generated by the rotation of the loading cam
4
is transmitted through the cam roller
5
to the input disk
1
, so that the input disk
1
can be rotated. Further, power generated by the rotation of the input disk
1
is transmitted through the power rollers
6
a
and
7
a
to the output disk
2
. As a result of this, the output disk
2
is rotated integrally with the output shaft
14
.
In speed change, the trunnions
10
and
11
are moved by a slight distance in the directions of the shift shafts
0
, respectively. That is, due to the movements of the trunnions
10
and
11
in the axial direction thereof, the intersection between the rotation axes of the power rollers
6
a,
7
a
and the axes of the input and output disks
1
,
2
is shifted slightly. This shift loses balance between the rotation peripheral speeds of the power rollers
6
a
,
7
a
and the rotation peripheral speed of the input disk
1
. In addition, due to the component of the rotation drive force of the input disk
1
, the power rollers
6
a
,
7
a
are allowed to inclinedly roll around the shift shafts
0
, whereby the power rollers
6
a
,
7
a
are allowed to incliningly roll on the curved surfaces of the input and output disks
1
,
2
. As a result of this, the speed ratio is changed, so that the speed of the vehicle is decreased or increased. As a toroidal-type continuously variable transmission having the above structure, for example, there is known a conventional transmission which is disclosed in JP-B-2-49411U.
In the above-mentioned toroidal-type continuously variable transmission, when driven, there is a fear that the power roller retainers of the power roller bearings interposed between the input and output disks can be damaged or broken. The reason for this is as follows: that is, when this toroidal-type continuously variable transmission is driven with a high load and high torque, the inner ring raceways of the power roller bearings, which have received loads from the input and output disks, are respectively deformed into an elliptic shape; and, when the rolling elements held by the retainers roll along the thus-deformed raceways, the rolling elements apply loads to the retainers. As a measure to deal with problem, there is known a method of enhancing the strength of the retainers. However, in this method, in case where the strength of the retainers is increased, seizure can occur between the contact portions between the retainers and power roller inner rings or outer rings, or the power roller inner rings or outer rings can be broken by the retainers.
SUMMARY OF THE INVENTION
The present invention aims at eliminating the above problems found in the conventional toroidal-type continuously variable transmission. Accordingly, it is an object of the invention to provide a toroidal-type continuously variable transmission in which the retainers of the power roller bearings are made of high-strength brass to thereby be able to optimize the strength of the retainers.
In attaining the above object, according to the invention, there is provided a toroidal-type continuously variable transmission, comprising: an input shaft; an input disk rotatable together with the input shaft; an output disk d
Fenstermacher David
NSK Ltd.
Sughrue & Mion, PLLC
LandOfFree
Toroidal-type continuously variable transmission does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Toroidal-type continuously variable transmission, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Toroidal-type continuously variable transmission will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3011377