U.S. patent application number 10/300894 was filed with the patent office on 2003-05-22 for toroidal-type continuously variable transmission.
This patent application is currently assigned to NSK LTD.. Invention is credited to Imanishi, Takashi.
Application Number | 20030096672 10/300894 |
Document ID | / |
Family ID | 19168533 |
Filed Date | 2003-05-22 |
United States Patent
Application |
20030096672 |
Kind Code |
A1 |
Imanishi, Takashi |
May 22, 2003 |
Toroidal-type continuously variable transmission
Abstract
A toroidal-type continuously variable transmission, has a first
continuously variable transmission mechanism and a second
continuously variable transmission mechanism: wherein the first and
second continuously variable transmission mechanisms are disposed
coaxially with each other; the first and second input disks are
connected together so as to be rotated in synchronization with each
other; the first and second output disks are formed as a unified
type output disk including traction surfaces on the two side
surfaces thereof; on the side portion at the outer-most outside
diameter of the unified type output disk, there is formed a datum
plane serving as a machining datum when the traction surfaces are
processed; and, an operation for finishing the datum plane is
carried out after the unified type output disk is heat treated.
Inventors: |
Imanishi, Takashi;
(Kanagawa, JP) |
Correspondence
Address: |
SUGHRUE MION, PLLC
2100 PENNSYLVANIA AVENUE, N.W.
WASHINGTON
DC
20037
US
|
Assignee: |
NSK LTD.
|
Family ID: |
19168533 |
Appl. No.: |
10/300894 |
Filed: |
November 21, 2002 |
Current U.S.
Class: |
476/42 |
Current CPC
Class: |
F16H 15/38 20130101;
F16H 2015/383 20130101; Y10T 29/4981 20150115 |
Class at
Publication: |
476/42 |
International
Class: |
F16H 015/38 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 22, 2001 |
JP |
P. 2001-357151 |
Claims
What is claimed is:
1. A toroidal-type continuously variable transmission, comprising a
first continuously variable transmission mechanism and a second
continuously variable transmission mechanism: said first
continuously variable transmission mechanism including a first
input disk, a first output disk disposed so as to be opposed to
said first input disk and, a pair of first power rollers
respectively held between said first input and output disks; and,
said second continuously variable transmission mechanism including
a second input disk, a second output disk disposed so as to be
opposed to said second input disk and, a pair of second power
rollers respectively held between said second input and output
disks, wherein said first and second continuously variable
transmission mechanisms are disposed coaxially with each other;
said first and second input disks are connected together so as to
be rotated in synchronization with each other; said first and
second output disks can be rotated integrally with each other; said
first and second output disks are formed as a unified type output
disk including on the two side surfaces thereof traction surfaces
to be contacted with said pair of first power rollers and said pair
of second power rollers; on the side portion at the outer-most
outside diameter of said unified type output disk, there is formed
a datum plane serving as a machining datum when said traction
surfaces are processed; and, an operation for finishing said datum
plane is carried out after said unified type output disk is heat
treated.
2. A toroidal-type continuously variable transmission comprising a
first continuously variable transmission mechanism and a second
continuously variable transmission mechanism: said first
continuously variable transmission mechanism including a first
input disk, a first output disk disposed so as to be opposed to
said first input disk and, a pair of first power rollers
respectively held between said first input and output disks; and,
said second continuously variable transmission mechanism including
a second input disk, a second output disk disposed so as to be
opposed to said second input disk, and a pair of second power
rollers respectively held between said second input and output
disks, wherein said first and second continuously variable
transmission mechanisms are disposed coaxially with each other;
said first and second input disks are connected together so as to
be rotated in synchronization with each other; said first and
second output disks can be rotated integrally with each other; said
first and second output disks are formed as a unified type output
disk including on the two side surfaces thereof traction surfaces
to be contacted with said pair of first power rollers and said pair
of second power rollers; on the end face at the outer-most outside
diameter of said unified type output disk, there is formed a
stepped portion projected from said end face and serving as a
machining datum when said traction surfaces are processed; and, an
operation for finishing said stepped portion is carried out after
said unified type output disk is heat treated.
3. The toroidal-type continuously variable transmission as set
forth in claim 2, wherein said stepped portion is cut and removed
after said traction surfaces are processed.
4. A toroidal-type continuously variable transmission, comprising a
first continuously variable transmission mechanism and a second
continuously variable transmission mechanism: said first
continuously variable transmission mechanism including a first
input disk, a first output disk disposed so as to be opposed to
said first input disk, and, a pair of first power rollers
respectively held between said first input and output disks; and,
said second continuously variable transmission mechanism including
a second input disk, a second output disk disposed so as to be
opposed to said second input disk, and, a pair of second power
rollers respectively held between said second input and output
disks, wherein said first and second continuously variable
transmission mechanisms are disposed coaxially with each other;
said first and second input disks are connected together so as to
be rotated in synchronization with each other; said first and
second output disks can be rotated integrally with each other; said
first and second output disks are formed as a unified type output
disk including on the two side surfaces thereof traction surfaces
to be contacted with said pair of first power rollers and said pair
of second power rollers; in the end face at the outer-most outside
diameter of said unified type output disk, there is formed a groove
portion serving as a machining datum when said traction surfaces
are processed; and, an operation for finishing said groove portion
is carried out after said unified type output disk is heat treated.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a toroidal-type
continuously variable transmission.
[0003] 2. Description of the Related Art
[0004] Conventionally, as a toroidal-type continuously variable
transmission, there is known an apparatus structured such that
first and second continuously variable transmission mechanisms are
disposed coaxially with each other: specifically, the first
continuously variable transmission mechanism comprises a first
input disk, a first output disk disposed so as to be opposed to the
first input disk and a pair of power rollers respectively held
between the first input and output disks; the second continuously
variable transmission mechanism comprises a second input disk, a
second output disk disposed so as to be opposed to the second input
disk and a pair of power rollers respectively held between the
second input and output disks; the first and second continuously
variable transmission mechanisms are disposed such that the first
and second input disks are disposed so as to be opposed to each
other in the axial direction thereof; the first and second input
disks are connected together so as to be rotated in synchronization
with each other; and, the first and second output disks can be
rotated integrally with each other.
[0005] By the way, for example, in JP-A-2000-104804 and U.S. Pat.
No. 5,607,372, there is disclosed an apparatus in which the
above-mentioned first and second output disks are structured as a
unified type output disk including on the two sides thereof
traction surfaces to be contacted with the above-mentioned pair of
first power rollers and the above-mentioned pair of second power
rollers.
[0006] However, the unified type output disk cannot be processed
with high precision and, especially, the traction surfaces of the
unified type output disk are difficult to work.
[0007] That is, when working the traction surfaces, there are
necessary surfaces which can be used as machining datum. One of
them is a datum surface which can be used to restrict the whirling
of the unified type output disk in the rotation direction thereof;
and as this datum surface, there is used a portion of the outside
diameter portion of the unified type output disk. As the other
datum surface, there is necessary a datum plane which is used to
fix the unified output disk in the axial direction thereof.
However, in the case of the unified type output disk disclosed in
either of the above-cited JP-A-2000-104804 or U.S. Pat. No.
5,607,372, the plane of the near-to-inside diameter portion of the
unified type output disk must be used as the machining datum
surface; and, therefore, when working the traction surfaces, the
whirling of the outside diameter portion of the unified type output
disk increases, with the result that, when grinding or
superfinishing the disk, the traction surfaces cannot be ground
with high precision. Such poor surface precision of the traction
surfaces not only can lower the power transmission efficiency of
the unified type output disk but also can make the gear change
operation thereof unstable.
SUMMARY OF THE INVENTION
[0008] The present invention aims at eliminating the
above-mentioned drawbacks 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 which uses a unified type output disk allowing its
traction surfaces to be processed with high precision, thereby
being able not only to enhance the power transmission efficiency
thereof but also to prevent the gear change operation from being
unstabilized.
[0009] In attaining the above object, according to a first aspect
of the invention, there is provided a toroidal-type continuously
variable transmission, comprising a first continuously variable
transmission mechanism and a second continuously variable
transmission mechanism: the first continuously variable
transmission mechanism including a first input disk, a first output
disk disposed so as to be opposed to the first input disk and, a
pair of first power rollers respectively held between the first
input and output disks; and, the second continuously variable
transmission mechanism including a second input disk, a second
output disk disposed so as to be opposed to the second input disk
and, a pair of second power rollers respectively held between the
second input and output disks, wherein the first and second
continuously variable transmission mechanisms are disposed
coaxially with each other; the first and second input disks are
connected together so as to be rotated in synchronization with each
other; the first and second output disks can be rotated integrally
with each other; the first and second output disks are formed as a
unified type output disk including on the two side surfaces thereof
traction surfaces to be contacted with the pair of first power
rollers and the pair of second power rollers; on the side portion
at the outer-most outside diameter of the unified type output disk,
there is formed a datum plane serving as a machining datum when the
traction surfaces are processed; and, an operation for finishing
the datum plane is carried out after the unified type output disk
is heat treated.
[0010] Also, according to the invention, as a machining datum,
instead of the datum plane, there can also be used a stepped
portion which is formed in the end face at the outer-most outside
diameter of the unified type output disk. And, the stepped portion
may be cut and removed after the traction surfaces of the unified
type output disk are processed.
[0011] Further, according to the invention, as the machining datum,
instead of the datum plane or stepped portion, there can also be
used a groove portion which is formed in the end face at the
outer-most outside diameter of the unified type output disk.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a section view of a toroidal-type continuously
variable transmission incorporating a unified type output disk
according to a first embodiment of the invention;
[0013] FIG. 2 is a section view of a unified type output disk
according to a second embodiment of the invention; and,
[0014] FIG. 3 is a section view of a unified type output disk
according to a third embodiment of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0015] Now, description will be given below of an embodiment of a
toroidal-type continuously variable transmission according to the
invention with reference to the accompanying drawings.
[0016] In FIG. 1, reference character 2 designates an input shaft
to which power from an engine (not shown) is input; and, a main
shaft 4 is rotatably disposed in such a manner that their
respective end faces are butted against each other.
[0017] On the main shaft 4, there are disposed a first continuously
variable transmission mechanism 6 and a second continuously
variable transmission mechanism 8 in such a manner that they are
coaxial with each other. The first continuously variable
transmission mechanism 6 comprises a first input disk 10a and a
first output disk 12a disposed so as to be opposed to each other,
and a pair of power rollers 14a (only one of the first power
rollers 14a is shown) respectively interposed between the first
input and output disks 10a, 12a; and, the second continuously
variable transmission mechanism 8 comprises a second input disk 10b
and a second output disk 12b disposed so as to be opposed to each
other, and a pair of power rollers 14b (only one of the second
power rollers 14b is shown) respectively interposed between the
second input and output disks lob, 12b.
[0018] The mutually opposed surfaces of the respective input disks
10a, 10b and output disks 12a, 12b are respectively formed as
traction surfaces; and, in a state where the first and second power
rollers 14a, 14b are in contact with the input disks 10a, 10b and
output disks 12a, 12b, the first and second power rollers 14a, 14b
can be swung.
[0019] And, between the first input disk 10a of the first
continuously variable transmission mechanism 6 and main shaft 4,
there is interposed a loading cam device 24. This loading cam
device 24 comprises a cam flange 22, which is engaged with the
input shaft 2 and can be rotated integrally therewith, and a
plurality of rollers 25 rollably held between the cam flange 22 and
first input disk 10a by a retainer 23. The torque of the input
shaft 2 can be input through the loading cam device 24 to the first
input disk 10a.
[0020] On the other hand, since the first and second output disks
12a, 12b are respectively connected to an output gear (not shown),
two kinds of torque respectively transmitted to the first and
second output disks 12a, 12b are collected together to the output
gear, and the thus collected torque is transmitted to an output
shaft (not shown) through a drive gear (not shown) in meshing
engagement with the output gear.
[0021] A first trunnion (not shown) for supporting the first power
roller 14a of the first continuously variable transmission
mechanism 6 is supported by a needle roller bearing (not shown) in
such a manner that it can be rotated and can be moved in the
vertical direction; and, this needle roller bearing is supported by
a yoke 44, while the yoke 44 is supported on a post 48 which
fixedly secured to a casing 46.
[0022] A second trunnion (not shown) for supporting the second
power roller 14b of the second continuously variable transmission
mechanism 8 is supported by a needle roller bearing (not shown) in
such a manner that it can be rotated and can be moved in the
vertical direction; and, this needle roller bearing is supported by
a yoke 50, while the yoke 50 is supported on a post 49 which
fixedly secured to the casing 46.
[0023] And, in case where torque is transmitted to the input shaft
2 as the engine is put into operation, this torque is transmitted
not only to the first input disk 10a through the loading cam device
24 but also to the second input disk 10b through the main shaft 4,
thereby rotating these first and second input disks 10a, 10b.
[0024] The torque, which is input to the first and second input
disks 10a, 10b, is transmitted through the first and second power
rollers 14a, 14b to the first and second output disks 12a, 12b;
and, at the then time, since the first and second power rollers
14a, 14b are controlled and inclinedly rotated by first and second
supporting mechanism, gear change ratios, which are responded to
inclined rotation angles of the first and second power rollers 14a,
14b, are generated in a continuously variable manner between the
first input and output disks 10a, 12a as well as between the second
input and outpost disks 10b, 12b.
[0025] By the way, the first and second output disks 12a, 12b
according to the present embodiment are a unified type output disk
which includes traction surfaces 54a, 54b, 54c, 54d on the two side
portions thereof (which is hereinafter referred to as a unified
type output disk 12A). On the side portion of the outer-most
outside diameter portion of this unified-type output disk, there is
formed a datum plane 56 which serves as a machining datum when
working the traction surfaces 54a, 54b, 54c, 54d. The length m of
the datum plane 56 in the diameter direction thereof (that is, the
direction which intersect at right angles to the axis of the main
shaft 4) is set at least 2 mm or more. Also, an operation for
finishing the datum plane 56 is executed after the unified output
disk 12A is heat treated.
[0026] And, referring to the operation for working the unified
output disk 12A, for example, according to a working method
disclosed in JP-A-2000-61702, while the datum plane 56 is matched
to the datum surface of a working apparatus such as a lathe, the
traction surfaces 54a, 54b, 54c, 54d are processed.
[0027] As in the above-mentioned structure, by working the
unified-type output disk 12A including the datum plane 56 on the
side portion of the outer-most outside diameter portion thereof,
the whirling of the outside diameter portion when working the
traction surfaces 54a, 54b, 54c, 54d can be reduced, so that, in
the grinding operation or in the superfinishing operation, the
traction surfaces 54a, 54b, 54c, 54d can be ground with high
precision. Therefore, in the case of a toroidal-type continuously
variable transmission incorporating therein the present unified
type output disk 12A, the power transmission efficiency thereof can
be prevented from being lowered and the gear change operation
thereof can be prevented from being unstabilized.
[0028] Also, due to heat treatment, the unified type output disk
12A is deformed to a slight degree; however, according to the
present embodiment, since the finishing operation of the datum
plane 56 is carried out after enforcement of the heat treatment of
the unified type output disk 12A, the influence of the deformation
of the unified type output disk 12A can be eliminated to thereby be
able to enhance the plane precision of the datum plane 56.
Therefore, in the case of the unified type output disk 12A
including the datum plane 56 of high plane precision, the working
of the traction surfaces 54a, 54b, 54c, 54d can be executed with
high precision.
[0029] Next, FIG. 2 is a half section view of a unified type output
disk 58 according to a second embodiment of the invention.
[0030] The unified type output disk 58 according to the second
embodiment includes traction surfaces 58a, 58b on the two side
portions thereof (by the way, although not shown, on the portion of
the disk 58 that is situated lower than the main shaft 4 as well,
there are formed other two traction surfaces). In the end portion
of the outer-most outside diameter portion of the present unified
type output disk, there is formed a stepped portion 60 which serves
as a machining datum when working the traction surfaces 58a, 58b.
The length m of the stepped portion 60 in the diameter direction
thereof (that is, the direction which intersect at right angles to
the axis of the main shaft 4) is set at least 2 mm or more.
[0031] Also, an operation for finishing the stepped portion 60 is
carried out after enforcement of the heat treatment of the unified
type output disk 58.
[0032] And, referring to an operation for working the unified
output disk 58, for example, according to a working method
disclosed in JP-A-2000-61702, while the stepped portion 60 is
matched to the datum recessed portion of a working apparatus such
as a lathe, the traction surfaces 58a, 58b maybe processed.
[0033] And, in case where the working operation of the traction
surfaces 58a, 58b and all of the remaining working operations are
completed, the stepped portion 60 is cut and removed to thereby
provide a unified type output disk 58 which does not include the
stepped portion 60.
[0034] As in the above-mentioned structure, by working the
unified-type output disk 58 including the stepped portion 60
provided on the end portion of the outer-most outside diameter
portion thereof, the whirling of the outside diameter portion when
working the traction surfaces 58a, 58b can be reduced, so that, in
the grinding operation or in the superfinishing operation, the
traction surfaces 58a, 58b can be ground with high precision.
Therefore, in the case of a toroidal-type continuously variable
transmission incorporating therein the present unified type output
disk 58, the power transmission efficiency thereof can be prevented
from being lowered and the gear change operation thereof can be
prevented from being unstabilized.
[0035] Also, since the operation for finishing the stepped portion
60 is carried out after enforcement of the heat treatment of the
unified type output disk 58, there can be eliminated the influence
of the deformation of the unified type output disk 58, which makes
it possible to enhance the plane precision of the wall surface of
the stepped portion 60. Therefore, in the case of the unified type
output disk 58 including the stepped portion 60 which is high
inplane precision, the traction surfaces 58a, 58b can be processed
with high precision.
[0036] Further, because the stepped portion 60 is cut and removed
after all of the working operations of the unified type output disk
58 are completed, the weight of the unified type output disk 58 can
be reduced, the fuel efficiency thereof can be enhanced and the
assembling efficiency can also be improved. In addition, since the
moment of inertia of the output disk 58 is also reduced, the
controlling performance thereof can be enhanced, so that the
responding performance of the output disk 58 to a sudden gear
change can be enhanced.
[0037] Next, FIG. 3 is a half section view of a unified output disk
62 according to a third embodiment of the invention.
[0038] The unified type output disk 62 according to the third
embodiment includes traction surfaces 62a, 62b on the two side
portions thereof (by the way, although not shown, on the portion of
the disk 62 that is situated lower than the main shaft 4 as well,
there are formed other two traction surfaces). In the end portion
of the outer-most outside diameter portion of the present unified
type output disk, there is formed a groove portion 64 which serves
as a machining datum when working the traction surfaces 62a, 62b.
The length m of the wall surface of the groove portion 64 in the
diameter direction thereof (that is, the direction which intersect
at right angles to the axis of the main shaft 4) is set at least 2
mm or more.
[0039] Also, the operation for finishing the groove portion 64 is
carried out after enforcement of the heat treatment of the unified
type output disk 62.
[0040] And, referring to the operation for working the unified
output disk 62, for example, according to a working method
disclosed in JP-A-2000-61702, while the groove portion 64 is
matched to the datum projecting portion of a working apparatus such
as a lathe, the traction surfaces 62a, 62b may be processed.
[0041] As in the above-mentioned structure, by working the
unified-type output disk 62 including the groove portion 64 formed
in the end portion of the outer-most outside diameter portion
thereof, the whirling of the outside diameter portion when working
the traction surfaces 62a, 62b can be reduced, so that, in the
grinding operation or in the superfinishing operation, the traction
surfaces 62a, 62b can be ground with high precision. Therefore, in
the case of a toroidal-type continuously variable transmission
incorporating the present unified type output disk 62 therein, the
power transmission efficiency thereof can be prevented from being
lowered and the gear change operation thereof can be prevented from
being unstabilized.
[0042] Also, since the operation for finishing the groove portion
64 is carried out after enforcement of the heat treatment of the
unified type output disk 62, there can be eliminated the influence
of the deformation of the unified type output disk, which makes it
possible to enhance the plane precision of the wall surface of the
groove portion 64. Therefore, in the case of the unified type
output disk 62 including the groove portion 64 which is high in
plane precision, the traction surfaces 62a, 62b can be processed
with high precision.
[0043] Further, provision of the groove portion 64 can reduce the
weight of the unified type output disk 62, can enhance the fuel
efficiency thereof and can improve the assembling efficiency
thereof. Also, since the moment of inertia of the output disk 62 is
also reduced, the controlling performance thereof can be enhanced,
so that the responding performance of the output disk 62 to a
sudden gear change can be enhanced.
[0044] By the way, in the above respective embodiments, description
has been given of a half-toroidal-type toroidal-type continuously
variable transmission; however, even in case where the
above-described unified type output disk is employed in a
full-toroidal-type toroidal-type continuously variable
transmission, there can also be obtained similar operation
effects.
[0045] As has been described heretofore, according to a
toroidal-type continuously variable transmission of the invention,
there can be reduced the whirling of the outside diameter portion
of a unified type output disk when working the traction surfaces of
the present output disk and thus, in the grinding operation and
superfinishing operation of the unified type output disk, the
traction surfaces thereof can be ground with high precision. Thanks
to this, in the case of a toroidal-type continuously variable
transmission which incorporates the present unified type output
disk therein, the power transmission efficiency thereof can be kept
from being lowered and the stability of the gear change operation
thereof can be enhanced.
[0046] Also, since the operation for finishing the datum plane is
carried out after enforcement of the heat treatment of the unified
type output disk, there can be eliminated the influence of the
deformation of the unified type output disk, thereby being able to
enhance the plane precision of the datum plane. Thanks to this, the
working of the traction surfaces of the unified type output disk
can be executed with high precision.
[0047] And, according to the toroidal-type continuously variable
transmission of the invention, since the traction surfaces of a
unified type output disk can be ground with high precision, in the
case of a toroidal-type continuously variable transmission which
incorporates the present unified type output disk therein, the
power transmission efficiency thereof can be kept from being
lowered and the stability of the gear change operation thereof can
be enhanced.
[0048] Also, since the operation for finishing the stepped portion
is carried out after enforcement of the heat treatment of the
unified type output disk, there can be eliminated the influence of
the deformation of the unified type output disk, which makes it
possible to enhance the plane precision of the wall surface of the
stepped portion. Therefore, the traction surfaces of the unified
type output disk can be processed with high precision.
[0049] And, according to the invention, because the stepped portion
is cut and removed after all of the working operations of the
unified type output disk are completed, the weight of the unified
type output disk can be reduced, the fuel efficiency thereof can be
enhanced and the assembling efficiency can also be improved. Also,
since the moment of inertia of the unified type output disk is also
reduced, the controlling performance thereof can be enhanced, so
that the responding performance of the present output disk to a
sudden gear change can be enhanced.
[0050] Further, according to a toroidal-type continuously variable
transmission of the invention, since it incorporates therein a
unified type output disk which includes a groove portion as a
machining datum, the power transmission efficiency thereof can be
kept from being lowered and the stability of the gear change
operation thereof can be enhanced.
[0051] Also, because the operation for finishing the groove portion
is carried out after enforcement of the heat treatment of the
unified type output disk, there can be eliminated the influence of
the deformation of the unified type output disk, which makes it
possible to enhance the plane precision of the wall surface of the
groove portion. Therefore, the traction surfaces of the unified
type output disk can be processed with high precision.
* * * * *