U.S. patent application number 09/822428 was filed with the patent office on 2001-08-23 for power roller unit and output disc unit for toroidal type continuously variable transmission.
Invention is credited to Fujinami, Makoto, Goto, Nobuo, Itoh, Hiroyuki, Kato, Hiroshi, Machida, Hisashi.
Application Number | 20010016535 09/822428 |
Document ID | / |
Family ID | 23063092 |
Filed Date | 2001-08-23 |
United States Patent
Application |
20010016535 |
Kind Code |
A1 |
Itoh, Hiroyuki ; et
al. |
August 23, 2001 |
Power roller unit and output disc unit for toroidal type
continuously variable transmission
Abstract
In order to facilitate an assembling operation of a structure
which is correctly operated with a proper positional relation, in a
power roller unit for a toroidal type continuously variable
transmission according to the present invention, a displacement
shaft, a power roller, a radial needle bearing, a thrust ball
bearing and a thrust needle bearing are pre-assembled to a
trunnion. After dimensional relations and operation conditions of
the constructural parts of the assembly or unit are ascertained,
the assembly is assembled within a housing together with other
unit, thereby completing the toroidal type continuously variable
transmission. That is to say, according to the present invention,
since the dimensional relations and operation conditions of the
constructural parts can be ascertained in a condition such parts
can easily be disassembled and re-assembled, a structure in which
the positional relation between the constructural parts is
maintained with high accuracy can be manufactured cheaply without
any troublesome operations.
Inventors: |
Itoh, Hiroyuki;
(Fujisawa-shi, JP) ; Machida, Hisashi;
(Fujisawa-shi, JP) ; Goto, Nobuo; (Fujisawa-shi,
JP) ; Fujinami, Makoto; (Chiba-shi, JP) ;
Kato, Hiroshi; (Fujisawa-shi, JP) |
Correspondence
Address: |
Mitchell W. Shapiro
Miles & Stockbridge P.C.
Suite 500
1751 Pinnacle Drive
McLean
VA
22102-3833
US
|
Family ID: |
23063092 |
Appl. No.: |
09/822428 |
Filed: |
April 2, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09822428 |
Apr 2, 2001 |
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09277959 |
Mar 29, 1999 |
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6238318 |
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Current U.S.
Class: |
476/46 ; 476/40;
476/42 |
Current CPC
Class: |
F16H 15/38 20130101 |
Class at
Publication: |
476/46 ; 476/42;
476/40 |
International
Class: |
F16H 015/38 |
Claims
What is claimed is:
1. A power roller unit for a toroidal type continuously variable
transmission, comprising: a trunnion having both end surfaces to
which coaxial pivot shafts are secured; a displacement shaft
supported on an intermediate portion of said trunnion; a power
roller rotatably supported around said displacement shaft at an
area protruded from an inner surface of said trunnion; and a thrust
bearing disposed between an outer surface of the power roller and
an inner surface of the intermediate portion of said trunnion; and
wherein said trunnion, said displacement shaft, said power roller
and said thrust bearing, which are discrete parts, are
pre-assembled to a positional relation to be attained after
assembling of said toroidal type continuously variable transmission
is completed, before these parts are assembled to said toroidal
type continuously variable transmission.
2. A power roller unit for a toroidal type continuously variable
transmission comprising: a trunnion having both end surfaces to
which coaxial pivot shafts are secured; first radial bearing
disposed around said pivot shafts; a circular hole formed in an
intermediate portion of said trunnion and directed perpendicular to
axial directions of the pivot shafts; a displacement shaft
including a support shaft portion and a pivot shaft portion which
are parallel and eccentric to each other, said support shaft
portion being rotatably supported within said circular hole via a
second radial bearing; a power roller rotatably supported around
said pivot shaft portion via a third radial bearing; and first and
second thrust bearings disposed between an outer surface of said
power roller and an inner surface of the intermediate portions of
said trunnion and arranged in series along a thrust load acting
direction; and wherein said trunnion, said first, second and third
radial bearings, said displacement shaft, said power roller, and
said first and second thrust bearings, which are discrete parts,
are pre-assembled to a positional relation to be attained after
assembling of said toroidal type continuously variable transmission
is completed, before these parts are assembled to said toroidal
type continuously variable transmission.
3. A power roller unit for a toroidal type continuously variable
transmission according to claim 2, wherein said power roller, said
displacement shaft, said third radial bearing and said first thrust
bearing are pre-assembled to a positional relation to be attained
after assembling of said power roller unit for said toroidal type
continuously variable transmission is completed, before these parts
are assembled to said power roller unit for said toroidal type
continuously variable transmission.
4. A power roller unit for a toroidal type continuously variable
transmission according to claim 1, wherein a proximal end portion
of a drive rod having an oil supply passage therein is fitted into
and secured to one of said paired pivot shafts secured to said both
end surfaces of said trunnion, and said drive rod and said one
pivot shaft are connected by a connecting pin also acting as a
blind peg for closing said oil supply passage, and further wherein
said trunnion, said drive rod and said connecting pin are
pre-assembled to a positional relation to be attained after
assembling of said power roller unit for said toroidal type
continuously variable transmission is completed, before these parts
are assembled to said power roller unit for said toroidal type
continuously variable transmission.
5. A power roller unit for a toroidal type continuously variable
transmission according to claim 4, wherein through holes for
permitting passage of said connecting pin to be formed in said one
pivot shaft and the proximal end of said drive rod are formed at
once in a condition that said drive rod is fitted into said one
pivot shaft.
6. A power roller unit for a toroidal type continuously variable
transmission according to claim 4, wherein an inner diameter of a
front end portion, along a connecting pin inserting direction, of a
through hole formed in said one pivot shaft is smaller than an
outer diameter of said connecting pin.
7. A power roller unit for a toroidal type continuously variable
transmission according to claim 6, wherein, among both end opening
portions of the through hole formed in said one pivot shaft, a rear
end opening portion along the connecting pin inserting direction is
deformed diametrically by caulking to prevent disengagement of said
connecting pin.
8. A power roller unit for a toroidal type continuously variable
transmission according to claim 2, wherein an assembling height of
the power roller unit for the toroidal type continuously variable
transmission which is a value regarding a distance from the inner
surface of said trunnion to a peripheral surface of the power
roller is adjusted by changing a thickness of said first or second
thrust bearing.
9. A power roller unit for a toroidal type continuously variable
transmission according to claim 1, wherein, regarding a plurality
of power roller units for constituting a single toroidal type
continuously variable transmission, relative error between
assembling heights of said power roller units which is a value
regarding a distance from the inner surface of said trunnion to a
peripheral surface of the power roller is limited to 0.1 mm or
less.
10. A power roller unit for a toroidal type continuously variable
transmission according to claim 1, wherein an outer peripheral
surface configuration of a portion of an end of said trunnion onto
which a lock member for locking a cable for synchronizing rocking
movement between a plurality of power roller units constituting a
single toroidal type continuously variable transmission is fitted
and secured is non-cylindrical.
11. A power roller unit for a toroidal type continuously variable
transmission according to claim 1, wherein a proximal end portion
of a drive rod having an oil supply passage therein is fitted into
and secured to one of said paired pivot shafts secured to said both
end surfaces of said trunnion, and an outer peripheral surface
configuration of a portion of said proximal end of said drive rod
onto which a precess cam for detecting displacement of said
trunnion is fitted and secured is non-cylindrical.
12. A power roller unit for a toroidal type continuously variable
transmission according to claim 2, wherein a stop tool for
preventing disengagement of said first radial bearing provided on
said pivot shaft is fitted on and supported by a portion of said
trunnion.
13. An output disc unit for a toroidal type continuously variable
transmission comprising: an output disc having an arc-shaped
concave inner surface and provided at its central portion with a
circular through hole passing through said disc axially and
rotatably supported around a periphery of an intermediate portion
of a rotary shaft; a radial rolling bearing disposed within said
through hole; and a stop ring locked within a lock groove formed in
an inner peripheral surface of said through hole and adapted to
prevent said radial rolling bearing from disengaging from said
through hole; and wherein said output disc, said radial rolling
bearing and said stop ring are pre-assembled to a positional
relation to be attained after the assembling of said toroidal type
continuously variable transmission is completed, before these parts
are assembled to said toroidal type continuously variable
transmission.
14. An output disc unit for a toroidal type continuously variable
transmission according to claim 13, wherein said through hole is
provided at its inner peripheral surface with a cylindrical surface
portion provided on an axial intermediate portion near an inside
surface and acting as an outer race track of said radial rolling
bearing, a female spline portion provided on the axial intermediate
portion near an outside surface, an inner surface side large
diameter portion provided at an axial end portion near the inside
surface, and an outer surface side large diameter portion provided
at an axial end portion near the outside surface, and inner
diameters of said cylindrical surface portion and said outer
surface side large diameter portion are greater than a diameter of
a circumscribed circle at a groove bottom of said female spline
portion.
15. An output disc unit for a toroidal type continuously variable
transmission according to claim 13, wherein, in a condition that
said rotary shaft is assembled to said toroidal type continuously
variable transmission, an output gear rotated in synchronous with
said output disc is rotatably supported on an intermediate portion
of said rotary shaft facing to an outer surface of said output
disc, and a portion of said output gear which faces to a thinnest
thickness portion of said output disc abuts against the outer
surface of said output disc.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a power roller unit and an
output disc unit for a toroidal type continuously variable
transmission and more particularly, it relates to a power roller
unit and an output disc unit which can make an assembling operation
easy as for a toroidal type continuously variable transmission
used, for example, as a transmission for a motor vehicle or a
transmissions for various industrial machines, and can improve
performance thereof by improving accuracy.
[0003] 2. Related Background Art
[0004] As a transmission for a motor vehicle, use of a toroidal
type continuously variable transmission as shown in FIGS. 21 and 22
has been investigated. For example, as disclosed in Japanese
Utility Model Application Laid-open No. 62-71465 (1987), in the
toroidal type continuously variable transmission, an input disc 2
is supported in coaxial with an input shaft 1 and an output disc 4
is secured to an end of an output shaft 3 disposed coaxially with
the input shaft 1. Within a casing containing the toroidal type
continuously variable transmission, there are provided trunnions 6
rockable around pivot shafts 5 disposed in twisted relations to the
input shaft 1 and the output shaft 3.
[0005] That is to say, the pivot shafts 5 are provided on outer
surfaces of these trunnions 6 at both ends thereof in a coaxial
relation. Intermediate portions of the trunnions 6 support proximal
ends of displacement shafts 7 so that, when the trunnions 6 are
rocked around the pivot shafts 5, inclined angles of the
displacement shafts 7 can be adjusted. Power rollers 8 are
rotatably supported around the displacement shafts 7 supported by
the trunnions 6. The power rollers 8 are interposed between opposed
inner surfaces 2a, 4a of an input disc 2 and of an output disc 4.
Each of the inner surfaces 2a, 4a has a concave surface obtained by
rotating an arc around each pivot shaft 5. Peripheral surfaces 8a
(formed as spherical convex surfaces) of the power rollers 8 abut
against the inner surfaces 2a, 4a.
[0006] An urging device 9 of loading cam type is disposed between
the input shaft 1 and the input disc 2 so that the input disc 2 can
be urged elastically toward the output disc 4 by the urging device
9. The urging device 9 comprises a cam plate 10 rotated together
with the input shaft 1, a plurality (for example, four) of rollers
12 rotatably retained (held) by a retainer (holder) 11. A drive cam
surface (circumferential uneven (convex and concave) surface) 13 is
formed one side (left side surface in FIGS. 21 and 22) of the cam
plate 10, and a driven cam surface 14 having similar configuration
is formed on an outer surface (right side surface in FIGS. 21 and
22) of the input disc 2. The plurality of rollers 12 are supported
for rotation around shafts directed radially with respect to a
center of the input shaft 1.
[0007] In use of the toroidal type continuously variable
transmission having the above-mentioned construction, when the cam
plate 10 is rotated as the input shaft 1 is rotated, the drive cam
surface 13 urges the plurality of rollers 12 against the driven cam
surface 14 formed on the outer surface of the input disc 2. As a
result, the input disc 2 is urged against the power rollers 8, and,
at the same time, the input disc 2 is rotated by the urging force
between the drive and driven cam surfaces 13, 14 and the plurality
of rollers 12. The, rotation of the input disc 2 is transmitted to
the output disc 4 through the power rollers 8, thereby rotating the
output shaft 3 secured to the output disc 4.
[0008] When a rotational speed ratio (transmission ratio) between
the input shaft 1 and the output shaft 3 is changed, and
particularly when speed reduction is effected between the input
shaft 1 and the output shaft 3, the trunnions 6 are rotated in
predetermined directions around the pivot shafts 5. And, the
displacement shafts 7 are inclined so that the peripheral surfaces
8a of the power rollers 8 abut against a center side portion of the
inner surface 2a of the input disc 2 and a peripheral side portion
of the inner surface 4a of the output disc 4, respectively, as
shown in FIG. 21. On the other hand, when speed increase is
effected, the trunnions 6 are rotated in reverse directions around
the pivot shafts 5. And, the displacement shafts 7 are inclined so
that the peripheral surfaces 8a of the power rollers 8 abut against
a peripheral side portion of the inner surface 2a of the input disc
2 and a center side portion of the inner surface 4a of the output
disc 4, respectively, as shown in FIG. 22. When the inclination
angles of the displacement shafts 7 are selected to intermediate
values between FIG. 21 and FIG. 22, an intermediate transmission
ratio can be obtained between the input shaft 1 and the output
shaft 3.
[0009] FIGS. 23 and 24 show an example of a more concrete toroidal
type continuously variable transmission disclosed in Japanese
Utility Model Laid-open No. 1-173552 (1989). An input disc 2 and an
output disc 4 are rotatably supported around a circular tubular
input shaft 115 via needle bearings 16, respectively. A cam plate
10 is spline-connected to a peripheral surface of an end (left end
in FIG. 23) of the input shaft 15 and is prevented from shifting a
way from the input disc 2 by a flange 17. The cam plate 10 and a
plurality of rollers 12 constitute an urging device 9 of loading
cam type for rotating the input disc 2 while urging the input disc
toward the output disc 4 on the basis of rotation of the input
shaft 15. An output gear 18 is coupled to the output shaft 4 via
keys 19 so that the input disc 4 and the output gear 18 can be
rotated in a synchronous manner.
[0010] Both ends of a pair of trunnions 6 are supported by a pair
of support plates 20 for rocking movement and displacement movement
in an axial direction (direction perpendicular to the plane of FIG.
23; left-and-right direction in FIG. 24). That is to say, radial
needle bearings (first radial bearings) 22 are provided between
outer peripheral surfaces of pivot shafts 5 secured to the both
ends of the trunnions 6 and inner peripheral surfaces of circular
holes 21 formed in both ends of the support plates 20. Outer
peripheral surfaces of outer races 23 of the radial needle bearings
22 are spherical convex surfaces so that these races are inserted
within the circular holes 21 for rocking movement and axial
displacement movement.
[0011] Displacement shafts 7 are supported within circular holes 24
formed in intermediate portions of the trunnions 6 supported
between the pair of support plates 20 for rocking movement and
axial displacement movement in this way. The displacement shaft 7
have support shaft portions 25 and pivot shaft portions 26 which
are parallel with each other and eccentric (offset) from each
other. The support shaft portions 25 are rotatably supported within
the circular holes 24 via radial needle bearings (second radial
bearings) 27. Power rollers 8 are rotatably supported around the
pivot shaft portions 26 via radial needle bearings (third radial
bearings) 28.
[0012] Incidentally, the pair of displacement shafts 7 are
diametrically opposed with each other with respect to the input
shaft 15. Directions of offset of the pivot shaft portions 26 of
the displacement shafts 7 with respect to the support shaft
portions 25 are the same (left and right opposite directions in
FIG. 24) with respect to the rotational direction of the input and
output discs 2, 4. Further, the offset directions are substantially
perpendicular to the direction of the input shaft 15. Accordingly,
the power rollers 8 are supported for a slight displacement
movement in the direction of the input shaft 15. As a result, even
if the power rollers 8 tend to displace along the axial direction
(left-and-right direction in FIG. 23; direction perpendicular to
the plane of FIG. 24) of the input shaft 15 due to elastic
deformation of the constructural parts based on great loads acting
on the constructural parts in accordance with the rotational force
transmitting conditions, the displacement can be absorbed without
excessive forces on the constructural parts.
[0013] Between outer surfaces of the power rollers 8 and inner
surfaces of the intermediate portions of the trunnions 6, in order
from the outer surfaces of the power rollers 8, there are provided
thrust ball bearings (first thrust bearings) 29 and thrust needle
bearings (second thrust bearings) 30 which are serially disposed
with respect to a thrust force acting direction (up-and-down
direction in FIGS. 23 and 24). The thrust ball bearings 29 support
the thrust loads acting on the power rollers 8 while permitting
rotations of the power rollers 8. Each such thrust ball bearings 29
includes a plurality of balls 31, an annular retainer 32 for
rollingly holding the balls 31, and an annular outer race 33. Inner
race tracks of the thrust ball bearings 29 are formed in the outer
surface of the power rollers 8 and outer race tracks are formed in
inner surfaces of the outer races 33.
[0014] Each of the thrust needle bearings 30 includes a race 34, a
retainer 35, and a plurality of needles 36. The race 34 and the
retainer 35 are assembled for slight displacement movement in a
rotational direction. Such thrust needle bearings 30 are interposed
between inner surfaces of the trunnions 6 and outer surfaces of the
outer races 33 in a condition that the races 34 abut against the
inner surfaces of the trunnions. Such thrust needle bearings 30
support the thrust loads acting on the outer races 33 while
permitting rocking movements of the outer races 33 around the
support shaft portions 25.
[0015] Further, drive rods 37 are coupled to one ends (left ends in
FIG. 24) of the trunnions 6, and drive pistons 38 are secured to
outer peripheral surfaces of intermediate portions of the drive
roads 37. The drive pistons 38 are mounted within corresponding
drive cylinders 39 in an oil-tight manner.
[0016] In case of the toroidal type continuously variable
transmission having the above-mentioned construction, the rotation
of the input shaft 15 is transmitted to the input disc 2 through
the urging device 9. The rotation of the input disc 2 is
transmitted to the output disc 4 through the pair of power rollers
8, and the rotation of the output disc 4 is taken from the output
gear 18. When a rotational speed ratio between the input shaft 15
and the output gear 18 is changed, the pair of pistons 38 are
displaced in opposite directions. In response to the displacement
of the pistons 38, the pair of trunnions 6 are displaced in
opposite directions, with the result that, for example, the lower
power roller in FIG. 24 is displaced to the right in FIG. 24 and
the upper power roller in FIG. 24 is displaced to the left in FIG.
24. Consequently, directions of tangential forces acting on contact
areas between the peripheral surfaces 8a of the power rollers 8 and
the inner surfaces 2a, 4a of the input and output discs 2, 4 are
changed. In response to the change in the force directions, the
trunnions 6 are rocked in opposite directions around pivot shafts 5
supported by the support plates 20. As a result, as shown in FIGS.
21 and 22, the contact positions between the peripheral surfaces 8a
of the power rollers 8 and the inner surfaces 2a, 4a are changed,
thereby changing the rotational speed ratio between the input shaft
15 and the output gear 18.
[0017] When the rotational speed ratio between the input shaft 15
and the output gear 18 is adjusted to a desired value, shift
amounts of the pistons 38 are regulated. The regulation of the
shift amounts of the pistons 38 is effected by engagement between
precess cams (not shown) secured to ends or intermediate portions
of the drive rods 37 and spools or sleeves of spool valves (not
shown). When the rotational force is transmitted between the input
shaft 15 and the output gear 18 as mentioned above, in response to
the deformation of the constructural parts, the power rollers 8 are
displaced in the axial direction of the input shaft 15, wit the
result that the displacement shafts 7 pivotally supporting the
power rollers 8 are slightly rotated around the support shaft
portions 25. As a result of such rotations, the outer surfaces of
the outer races 33 of the thrust ball bearings 20 and the inner
surfaces of the trunnions 6 are displaced relative to each other.
Since the thrust needle bearings 30 are disposed between the outer
surfaces and the inner surfaces, a force required for causing the
relative rotation is small. Accordingly, as mentioned above, a
force for changing the inclined angle of each displacement shaft 7
can be made smaller.
[0018] Further, as shown in FIGS. 25 and 26, there has also been
proposed constructions in which two input discs 102A, 102B and two
output discs 104 are disposed around an input shaft 15 in order to
increase torque which can be transmitted and these two input and
output discs 102A, 103B, 104 are arranged in parallel with respect
to a force transmitting direction. In both constructions shown in
FIGS. 25 and 26, an output gear 121a is supported on a periphery of
an intermediate portion of an input shaft 115a for rotational
movement with respect to the input shaft 115a and the output discs
104 are spline-connected to cylindrical both ends at a center of
the output gear 121a. Needle bearings 116 are disposed between
inner peripheral surfaces of the output discs 104 and an outer
peripheral surface of the input shaft 115a so that the output discs
104 are supported for rotational movement around and with respect
to the input shaft 115a and displacement movement in an axial
direction of the input shaft 115a. Further, the input discs 102A,
102B are supported on both ends of the input shaft 115a for
rotational movement together with the input shaft 115a. The input
shaft 115a is rotated by a drive shaft 135 via an urging device 109
of loading cam type. Incidentally, a radial bearing 136 such as a
sliding bearing or a needle bearing is disposed between an outer
peripheral surface of a distal end (left end in FIGS. 25 and 26) of
the drive shaft 135 and an inner peripheral surface of a proximal
end (right end in FIGS. 25 and 26) of the input shaft 115a.
Accordingly, the drive shaft 135 and the input shaft 115a are
assembled so that they can be displaced in the rotational direction
in a coaxial relation.
[0019] However, a rear surface (left surface in FIGS. 25 and 26) of
one 102A (left one in FIGS. 25 and 26) of the input discs abuts
against a loading nut 137 directly (in the construction shown in
FIG. 26) or via a coned disc spring 151 (in the construction shown
in FIG. 25), thereby substantially preventing axial (left-and-right
direction in FIGS. 25 and 26) displacement of the input disc with
respect to the input shaft 115a. On the other hand, the input disc
102B opposed to a cam plate 110 is supported on the input shaft
115a via a ball spline 138 for axial displacement movement. A coned
disc spring 139 and a thrust needle bearing 140 are disposed in
series between a rear surface (right surface in FIGS. 25 and 26) of
the input disc 102B and a front surface (left surface in FIGS. 25
and 26) of the cam plate 110. The coned disc spring 139 serves to
apply pre-pressure to contact areas between inner surfaces 102a,
104a of the discs 102A, 102B, 104 and peripheral surfaces 108a of
the power rollers 108. When the urging device 109 is operated, the
thrust needle bearing 140 serves to permit relative rotation
between the input disc 102B and the cam plate 110.
[0020] In case of the construction shown in FIG. 25, the output
gear 121a is rotatably supported by a partition wall 141 within a
housing via a pair of ball bearings 142 of angular type in a
condition that displacement of the output gear is prevented. On the
other hand, in case of the construction shown in FIG. 26, the
output shaft 121a can freely be displaced in the axial direction.
Incidentally, as shown in FIGS. 25 and 26, the reason why the
toroidal type continuously variable transmission of so-called
double cavity type in which the two input discs 102A, 102B and
output discs 104 are disposed in parallel with respect to the power
transmitting direction supports one or both of the input discs
102A, 102B via the ball splines 138, 138a for axial displacement
movement is that the input discs 102A, 102B can be displaced in the
axial direction of the input shaft 115a in response to deformation
of the constructural parts caused by the operation of the urging
device 9 while rotating the discs 102A, 102B in a synchronous
manner.
[0021] When the toroidal type continuously variable transmission
having the above-mentioned construction is assembled,
conventionally, various constructural parts were assembled
successively within the housing 40 (FIG. 24) containing the
toroidal type continuously variable transmission. Accordingly,
positional deviation between the parts due to total dimensional
errors of the constructural parts, i.e., the fact whether the
constructural parts are operated correctly or not could not be
ascertained before all of the constructural parts are completely
assembled within the housing 40.
[0022] In order to ensure efficiency and endurance of the toroidal
type continuously variable transmission, positional relations
between the constructural parts must be maintained with high
accuracy. Thus, if the positional deviation between the parts due
to the total dimensional errors of the constructural parts becomes
great, the toroidal type continuously variable transmission once
assembled within the housing must be disassembled and re-assembled
in order to reduce the positional deviation by combining various
parts with other parts.
[0023] When the toroidal type continuously variable transmission is
assembled in this way, the assembly operation of the toroidal type
continuously variable transmission becomes complicated and cost of
the transmission cannot be reduced.
SUMMARY OF THE INVENTION
[0024] A power roller unit and an output disc unit for a toroidal
type continuously variable transmission according to the present
invention is invented in consideration of the above-mentioned
circumstances.
[0025] For example, the power roller unit for the toroidal type
continuously variable transmission according to the present
invention may comprise a trunnion having both end surfaces to which
coaxial pivot shafts are secured, first radial bearings disposed
around the pivot shafts, a circular hole formed in an intermediate
portion of the trunnion and directed perpendicular to axial
directions of the pivot shafts, a displacement shaft including a
support shaft portion and a pivot shaft portion which are parallel
and eccentric to each other, the support shaft portion being
rotatably supported within the circular hole via a second radial
bearing, a power roller rotatably supported around the pivot shaft
portion via a third radial bearing, and first and second thrust
bearings disposed between an outer surface of the power roller and
an inner surface of the intermediate portion of the trunnion and
arranged in series along a thrust load acting direction. The
trunnion, first, second and third radial bearings, displacement
shaft, power roller, and first and second thrust bearings, which
are discrete parts, are pre-assembled to a positional relation to
be attained after assembling of the toroidal type continuously
variable transmission is completed, before these parts are
assembled to that toroidal type continuously variable
transmission.
[0026] In the toroidal type continuously variable transmission to
which the power roller units according to the present invention
having the above-mentioned construction are assembled, in
accordance with the same operation as that of the above-mentioned
conventional toroidal type continuously variable transmission, a
rotational force is transmitted between an input disc and an output
disc, and a rotational speed ratio between these discs is changed
by changing inclination angles of the trunnions.
[0027] Particularly, in case of the power roller unit for the
toroidal type continuously variable transmission according to the
present invention, the trunnion, first, second and third radial
bearings, displacement shaft, power roller, and first and second
thrust bearings, which are discrete parts, are pre-assembled to the
positional relation to be attained after the assembling of the
toroidal type continuously variable transmission is completed,
before these parts are assembled to the toroidal type continuously
variable transmission. Thus, positional deviation between
constructural parts due to total dimensional errors of the
constructural parts, i.e., the fact whether the constructural parts
are operated correctly or not can be ascertained before these
constructural parts are assembled within a housing. Accordingly,
the positional relation between the constructural parts can be
maintained with high accuracy without disassembling and
re-assembling the entire toroidal type continuously variable
transmission. Therefore, transmission efficiency and endurance of
the toroidal type continuously variable transmission can be
improved while reducing cost of product by increasing assembling
efficiency. In case of a power roller unit for a toroidal type
continuously variable transmission as specified in claim 1,
although the number of constructural parts is smaller, the same
advantage can be achieved.
[0028] In an output disc unit for toroidal type continuously
variable transmission according to the present invention, an output
disc having an arc-shaped concave inner surface and provided at its
central portion with a circular through hole passing through the
disc axially and rotatably supported around a periphery of an
intermediate portion of a rotary shaft, a radial rolling bearing
disposed within the through hole, and a stop ring locked within a
lock groove formed in an inner peripheral surface of the through
hole and adapted to prevent the radial rolling bearing from
disengaging from the through hole are pre-assembled to the
positional relation to be attained after the assembling of the
toroidal type continuously variable transmission is completed,
before these parts are assembled to the toroidal type continuously
variable transmission.
[0029] In the toroidal type continuously variable transmission
including the output disc unit according to the present invention
having the above-mentioned construction, in accordance with the
same operation as that of the above-mentioned conventional toroidal
type continuously variable transmission, a rotational force is
transmitted between an input disc and an output disc, and a
rotational speed ratio between these discs is changed by changing
inclination angles of the trunnions.
[0030] Particularly, in case of the output disc unit for the
toroidal type continuously variable transmission according to the
present invention, the output disc, radial bearing and stop ring,
which are discrete parts, are pre-assembled to the positional
relation to be attained after the assembling of the toroidal type
continuously variable transmission is completed, before these parts
are assembled to the toroidal type continuously variable
transmission. Thus, the fact whether the constructural parts are
operated correctly or not can be ascertained before these
constructural parts are assembled within a housing. Accordingly,
the positional relation between the constructural parts can be
maintained with high accuracy without disassembling and
re-assembling the entire toroidal type continuously variable
transmission. Therefore, transmission efficiency and endurance of
the toroidal type continuously variable transmission can be
improved while reducing cost of product by increasing assembling
efficiency.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] FIG. 1 is a sectional view showing a first embodiment of the
present invention as a condition that trunnions, displacement
shafts, power rollers and drive rods are assembled via a plurality
of rolling bearings;
[0032] FIG. 2 is a view from the right in FIG. 1;
[0033] FIG. 3 is a sectional view showing a condition that the
trunnions and the drive rods are assembled;
[0034] FIG. 4 is a sectional view taken along the line IV-IV in
FIG. 3;
[0035] FIG. 5 is a sectional view showing a condition that the
power rollers and the displacement shafts are assembled via the
plurality of rolling bearings;
[0036] FIG. 6 is a view showing a condition that an assembled
height of a power roller unit is measured, looked at from a
direction same as FIG. 2;
[0037] FIG. 7 is a sectional view showing a condition that a
function of the power roller unit is recognized, looked at from a
direction same as FIG. 1;
[0038] FIG. 8 is a view looked at from the right in FIG. 7;
[0039] FIG. 9 is a sectional view similar to FIG. 1, showing a
second embodiment of the present invention;
[0040] FIG. 10 is a view looked at from the right in FIG. 9;
[0041] FIG. 11 is a sectional view similar to FIG. 1, showing a
third embodiment of the present invention;
[0042] FIG. 12 is a view looked at from the right in FIG. 1;
[0043] FIG. 13 is a sectional view similar to FIG. 1, showing a
fourth embodiment of the present invention;
[0044] FIG. 14 is a view looked at from the right in FIG. 13;
[0045] FIG. 15 is an enlarged view showing a central portion of
FIG. 14;
[0046] FIG. 16 is a sectional view showing a fifth embodiment of
the present invention as a condition that an output disc, a needle
bearing and a stop ring are assembled;
[0047] FIG. 17 is an enlarged view of a part X in FIG. 16;
[0048] FIG. 18 is a sectional view showing a condition that the
output disc is assembled to a toroidal type continuously variable
transmission;
[0049] FIG. 19 is a sectional view similar to FIG. 18, showing a
sixth embodiment of the present invention;
[0050] FIG. 20 is a sectional view similar to FIG. 18, showing a
seventh embodiment of the present invention;
[0051] FIG. 21 is a side view of a conventional toroidal type
continuously variable transmission in a maximum speed reduction
condition;
[0052] FIG. 22 is a side view showing a maximum speed increase
condition;
[0053] FIG. 23 is a sectional view showing a first example of a
conventional concrete construction;
[0054] FIG. 24 is a sectional view taken along the line XXIV-XXIV
in FIG. 23;
[0055] FIG. 25 is a partial sectional view showing a second example
of a conventional concrete construction; and
[0056] FIG. 26 is a partial sectional view showing a third
example.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0057] FIGS. 1 to 8 show a first embodiment of the present
invention. Incidentally, the feature of the present invention is
that an arrangement which bearings for supporting trunnions 6
rockably, displacement shafts 7, power rollers 8, and bearings for
supporting the power rollers 8 rotatably and rockably are assembled
to the trunnions 6 is handled as a unit. Since the other
constructions and operation are the same as those of the
above-mentioned conventional technique, explanation thereof will be
omitted and only the characteristics of the present invention will
be mainly explained.
[0058] Each of trunnions 6 formed integrally by forging and cutting
(machining) metal having great rigidity such as alloy of iron group
is provided at its both ends with a pair of coaxial pivot shafts 5.
A pair of outer races 23 are disposed around the pivot shafts 5 in
a coaxial relation to the pivot shafts 5. Each outer race 23 has a
spherical convex outer peripheral surface and a cylindrical inner
peripheral surface. A plurality of needles 41 are rotatably
disposed between the inner peripheral surfaces of the races 23 and
outer peripheral surfaces of the pivot shafts 5 to form radial
needle bearings (first radial bearings) 22. Thrust washers 42 are
disposed between inner end surfaces (central side end surfaces of
the trunnions 6) of the outer races 23 constituting the radial
needle bearings 22 and the trunnion 6 to avoid rubbing between the
inner end surfaces of the outer races 23 and the trunnion 6,
thereby preventing damage of the trunnion 6.
[0059] A circular hole 24 for supporting a displacement shaft 7
(described later) is formed in an intermediate portion of the
trunnion 6. A center line of the circular hole 24 extends
perpendicular to axial directions of the pivot shafts 5. A support
shaft portion 25 constituting the displacement shaft 7 is rotatably
supported within the circular hole 24 via a radial needle bearing
(second radial bearing) 27. The radial needle bearing 27 comprises
a cylindrical race 44 and a plurality of needles 45. An outer
diameter of the race 44 is the same as or slightly greater than an
inner diameter of the circular hole 24. Accordingly, the race 44 is
fitted into the circular hole 24 with no interference (no fitting
tolerance) or slight interference. In a condition that the support
shaft portion 25 is rotatably supported within the circular hole 24
via the radial needle bearing 27, a pivot shaft portion 26
constituting the displacement shaft 7 protrudes from an inner side
surface of the trunnion 6.
[0060] A power roller 8 is rotatably supported, via a radial needle
bearing (third radial bearing) 28, around the pivot shaft portion
26 protruded from the inner side surface of the trunnion 6 in this
way. Between an outer surface of the power roller 8 and an inner
surface of the intermediate portion of the trunnion 6, there are
provided a thrust ball bearing (first thrust bearing) 29 and a
thrust needle bearing (second thrust bearing) 30 which are disposed
in series with respect to a thrust load acting direction
(up-and-down direction in FIGS. 1 and 2). The thrust ball bearing
29 includes a plurality of balls 31 disposed between an inner race
track 46 formed in the outer surface of the power roller 8 and an
outer race track 47 formed in an inner surface of an outer race 33.
The thrust needle bearing 30 includes a race 34 provided on the
inner surface of the trunnion 6, and a plurality of needles 36
rotatably held by a retainer 35. An angular bearing with an
appropriate contact angle can be used instead of the thrust ball
bearing.
[0061] A proximal end (left end in FIGS. 1, 3 and 7) of a drive rod
37 is fitted into and secured to one (right in FIG. 1) of the
paired pivot shafts 5. In order to fit and secure the proximal end
of the drive rod 37 into one of the paired pivot shafts 5, a
coupling pin 48 formed from metallic material having high hardness
is bridged between the pivot shaft 5 and the proximal end of the
drive rod 37. To this end, through holes 49, 50 extending
diametrical direction are formed in the proximal end of the drive
rod 37 and the pivot shaft 5. An inner diameter of the through hole
49 formed in the proximal end of the drive rod 37 are uniform along
its entire length. On the other hand, a smaller diameter portion 51
is formed at one end (right end in FIG. 4) of the through hole 50
formed in the pivot shaft 5. When the pivot shaft 5 and the drive
rod 37 are interconnected, first of all, the proximal end of the
drive rod 37 is press-fitted into the pivot shaft 5. In this case,
the through holes 49, 50 are not yet formed. After the proximal end
of the drive rod 37 is pushed into the pivot shaft 5 by a
predetermined amount, the thorough holes 49, 50 are formed by a
drilling machine and the like. Accordingly, a troublesome operation
in which the through holes 49, 50 are aligned with each other after
the drive rod 37 is pushed into the pivot shaft 5 is not required.
Then, the coupling pin 48 is press-fitted in the through holes 49,
50 aligned in this way, from a side opposite to the smaller
diameter portion 51. After a inserted tip end of the coupling pin
48 abuts against an end of the smaller diameter portion 51, a
caulking portion 52 is formed on the other end of the through hole
50, thereby preventing the coupling pin 48 from disengaging from
the through holes 49, 50.
[0062] In a condition that the drive rod 37 is connected to the
pivot shaft 5 provided at the end of the trunnion 6 in this way, a
positional relation between the trunnion 6 and the drive rod 37 is
determined reasonably. Even after long term use, the coupling pin
48 is not disengaged from the through holes 49, 50 thereby to
prevent deviation of the positional relation between the trunnion 6
and the drive rod 37 without fail. Accordingly, a positional
relation between a precess cam secured to the drive rod 87 and the
trunnion 6 is surely maintained to positively control postures of
the trunnion 6 and the power roller 8 supported on the inner
surface of the trunnion 6. Incidentally, an oil supply passage 62
for supplying lubricating oil to a rotational support part of the
power roller 8 is formed in the trunnion 6 and the drive rod 37.
The coupling pin 48 also acts as a blank plug (blind peg) for
closing a part of the through hole constituting the oil supply
passage 62 to supply the lubricating oil to a desired area.
[0063] A fitting protruded portion 53 having an elliptical outer
peripheral surface shape is formed on a tip end surface of the
pivot shaft 5 to which the drive rod 37 is connected, and a fitting
support portion 54 having an elliptical outer peripheral surface
shape is formed on a tip end (right end in FIG. 1) of the drive rod
37. A pulley-shaped lock member for locking a cable (not shown) for
synchronizing rocking movements of the front and rear trunnions 6
constituting the toroidal type continuously variable transmission
of double cavity type is fitted on and secured to the fitting
protruded portion 53. On the other hand, a precess cam for
detecting displacement of the drive rod 37 and the trunnion 6 is
fitted on and supported by the fitting support portion 54. In a
condition that the lock member or the precess cam is fitted on the
fitting protruded portion 53 or the fitting support portion 54
having the elliptical outer peripheral surface shape, the lock
member or the precess cam is not deviated from the drive rod 37 and
the trunnion 6 in a rotational direction. Accordingly, the rocking
movements between the front and rear trunnions 6 can surely be
effected by the cable, and the postures of the trunnion 6 and of
the power roller 8 supported on the inner surface of the trunnion 6
can surely be controlled by the precess cam.
[0064] In case of the power roller unit for the toroidal type
continuously variable transmission according to the present
invention, the trunnion 6, radial needle bearings 22, 27, 28,
displacement shaft 7, power roller 8, thrust ball bearing 29,
thrust needle bearing 30 and drive rod 37, which are discrete
parts, are pre-assembled to the positional relation to be attained
after the assembling of the toroidal type continuously variable
transmission as shown in FIGS. 23 and 24 is completed, before these
parts are assembled to the toroidal type continuously variable
transmission. In order to assemble these parts 6, 22, 27, 28, 7, 8,
29, 30, 37 in this way, a first unit 56 in which the trunnion 6 is
connected and secured to the connecting rod 37 as shown in FIG. 3
and a second unit 57 in which the displacement shaft 7 and the
power roller 8 and the thrust ball bearing 29 are combined as shown
in FIG. 5 are assembled previously. And, by assembling these first
and second units 56, 57 via the radial needle bearing 27 and the
thrust needle bearing 30, a power roller unit 58 as shown in FIGS.
1, 2, 6, 7 and 8 is obtained.
[0065] After the power roller unit 58 is obtained by assembling the
parts 6, 22, 27, 28, 7, 8, 29, 30, 37 as mentioned above, as shown
in FIGS. 6 to 8, the dimension and operating condition of each part
are ascertained. FIG. 6 shows a condition that a relation between
an outer peripheral surface position of the outer race 23
constituting the radial needle bearing 22 for supporting the
trunnion 6 with respect to the support plates 20 (FIG. 24) and a
position of the peripheral surface 8a of the power roller 8 is
measured. In order to perform such measurement, the outer races 23
of the radial needle bearings 22 provided around the periphery of
the pivot shafts 5 on the both ends of the trunnion 6 are rested on
V-shaped blocks 59 installed on a fixed table 61, respectively. A
measuring tool 60 having a configuration corresponding to the inner
surfaces 2a, 4a (FIGS. 21 to 23) of the input and output discs 2, 4
is put on the power roller 8, and a distance (height) between an
upper surface of the fixed table 61 and an upper surface of the
measuring tool 60 is measured. By combining a plurality of power
roller units 58 having small height difference, the toroidal type
continuously variable transmission is obtained.
[0066] That is to say, a plural sets of power roller units 58 are
incorporated into one toroidal type continuously variable
transmission. For example, in case of a so-called toroidal type
continuously variable transmission of single cavity type in which
only one pair of input and output discs 2, 4, two or three sets of
power roller units 58 are incorporated. On the other hand, in case
of a so-called toroidal type continuously variable transmission of
double cavity type in which two pairs of input and output discs 2,
4 are provided and the two pairs of input and output discs 2, 4 are
arranged in parallel to each other with respect to a power
transmitting direction, four to six sets of power roller units 58
are incorporated. Regarding the plural sets of power roller units
58 incorporated into one toroidal type continuously variable
transmission in this way, if the above-mentioned heights are
different from each other, contact areas between the peripheral
surfaces 8a of the power rollers 8 and the inner surfaces 2a, 4a of
the input and output discs 2, 4 will be slipped or the speed ratios
of the power rollers 8 will not be synchronized correctly, thereby
resulting in poor transmission.
[0067] To avoid this, regarding the plural sets of power roller
units 58 incorporated into one toroidal type continuously variable
transmission, a plural sets of power roller units 58 having the
height difference of 0.1 mm or less are selected, and one toroidal
type continuously variable transmission is assembled by using such
power roller units 58. The reason why the predetermined value is
set to 0.1 mm is based on tests effected by the Inventor. The tests
were effected by using toroidal type continuously variable
transmissions of double cavity type in which two pairs of input and
output discs 2, 4 are provided and two power roller units 58 (four
in total) are disposed between the respective inner surfaces 2a, 4a
of the input and output discs 2, 4, and influence of the height
difference of each power roller unit 58 and temperature of traction
oil filled within the housing 40 (FIG. 24) upon the slipping
between the peripheral surface 8a and the inner surfaces 2a, 4a and
upon the transmission condition was measured. Incidentally, the
power roller units having proportions as shown and including the
power roller 8 having an outer diameter of 78 mm were used. The
test results are shown in the following Table 1.
1TABLE 1 Assembling height of power roller unit (deviation against
proper size: mm) No. 1 No. 2 No. 3 No. 4 LDMV Slip limit TC -0.03
-0.01 -0.02 -0.01 0.02 not slip at good 130.degree. C. 0 0.02 -0.01
0 0.03 same as above good 0.05 0.05 0.06 0.08 0.03 same as above
good -0.02 0.03 0.03 -0.02 0.05 same as above good 0.05 0.04 0.01 0
0.05 same as above good 0.06 0.07 0 0.05 0.07 same as above good
0.05 0.06 0.07 -0.01 0.08 same as above good -0.02 0.06 0.01 0.05
0.08 same as above good 0.01 0.05 -0.04 0.05 0.09 same as above
good 0.05 -0.01 -0.03 -0.04 0.09 same as above good -0.03 -0.03
0.01 -0.08 0.09 same as above good -0.07 -0.01 -0.02 0.04 0.11 slip
at 125.degree. C. good -0.07 0.04 0 0.04 0.11 slip at 118.degree.
C. good -0.1 0.03 0.02 0.03 0.13 slip at 103.degree. C. bad -0.12
0.03 0.04 -0.05 0.16 slip at 84.degree. C. bad "LDMV" = maximum
value of relative difference; "TC" = transmission condition.
[0068] As apparent from the above Table 1, regarding the plural
sets of power roller units 58 incorporated into one toroidal type
continuously variable transmission, so long as the difference of
height up to the peripheral surface 8a of the power roller 8 based
on the outer peripheral surfaces of the outer races 23 of the
radial needle bearings 22 for supporting the pivot shafts 5 (i.e.,
difference of assembling height of the power roller unit 58) is
suppressed to 0.1 mm or less, the slip can be prevented at the
contact area between the peripheral surface 8a and the inner
surfaces 2a, 4a of the input and output discs 2, 4 and the
transmission condition can be maintained to the good condition.
Incidentally, in order to obtain plural sets of power roller units
58 having the height difference smaller than 0.1 mm, although power
roller units satisfying the requirement may be selected among a
number of power roller units, a thickness of the race 34
constituting the thrust needle bearing 30 may be changed. That is
to say, as the race 34, a plurality kinds of races having
thicknesses which slightly differ are prepared, and, after the
measuring operation as shown in FIG. 6 was effected, by
incorporating a proper race 34, the height difference can be
limited to the predetermined value. Also, by changing a thickness
of the outer race 33, the height difference can be limited to the
predetermined value. When the measuring operation is performed
before the stop ring 63 is mounted on the end of the support shaft
portion 25, the race 34 can easily be replaced. Further, as is in
the present invention, when the height difference is measured at
the stage of the power roller unit 58, the occurrence of the slip
and poor transmission can be prevented without complicated and
troublesome correspondence to the other constructural parts (since
cause of the poor operation can easily and reliably be investigated
and specified).
[0069] After the power roller unit 58 is assembled, the difference
of height up to the peripheral surface 8a of the power roller 8
based on the outer peripheral surfaces of the outer races 23 is
measured and the function (such as run out and parallelism of the
peripheral surface 8a) of the power roller unit 58 is ascertained.
The function ascertaining operation is performed, for example, as
shown in FIGS. 7 and 8. First of all, in order to measure the run
out (whirling) and parallelism of the peripheral surface 8a, in a
condition that the outer peripheral surfaces of the outer races 23
constituting the radial needle bearings 22 provided around the
pivot shafts 5 on both ends of the trunnion 6 is rested on a
reference plane (or the outer peripheral surfaces of the pivot
shafts 5 with radial needle bearings 22 omitted is directly rested
on the reference plane), the power roller 8 is rotated. And,
displacement of a part (rolling surface portion) of the peripheral
surface 8a of the power roller 8 which is rollingly contacted with
the inner surfaces 2a, 4a of the input and output discs 2, 4 is
measured by a precise measuring device such as a comparator,
thereby measuring the run out and parallelism. Further, the run out
of the tip end portion of the drive rod 37 is measured by rocking
the trunnion 6 and the drive rod 37 around the radial needle
bearings 22, and it is ascertained whether the run out is included
within an allowable range or not. Further, it is ascertained
whether accuracy and configuration of trace of the rocking movement
of the power roller 8 rotatably supported around the pivot shaft
portion 26 of the displacement shaft 7 are performed as design
specification, by rocking the displacement shaft 7 around the
support shaft portion 25. Further, it is ascertained whether the
radial needle bearings 22 are rotated smoothly.
[0070] Regarding a power roller unit in which it is judged that the
relation between the outer peripheral surface position of the outer
race 23 constituting the radial needle bearing 22 and the position
of the peripheral surface 8a of the power roller 8 is proper and it
is judged that the functions of various parts are proper by the
above-mentioned operation, the constructural parts 6, 22, 27, 28,
7, 8, 29, 30, 37 are temporarily fixed by using appropriate tools.
On the other hand, if the positional relation or the functions are
not proper, these parts are disassembled and are replaced by other
parts and are re-assembled.
[0071] According to the present invention, the positional deviation
between the constructural parts due to total dimensional errors of
the constructural parts, i.e., the fact whether the constructural
parts are operated correctly or not can be ascertained before these
constructural parts are assembled within the housing 40.
Accordingly, the positional relation between the constructural
parts can be maintained with high accuracy to ensure the
transmission efficiency and endurance of the toroidal type
continuously variable transmission without the troublesome
operations such as disassembling and re-assembling of the entire
toroidal type continuously variable transmission. The power roller
unit 58 in which the parts 6, 22, 27, 28, 7, 8, 29, 30, 37 are
assembled is incorporated into the housing together with an input
disc unit and an output disc unit in which a plurality parts are
assembled, thereby providing the toroidal type continuously
variable transmission. Similar to the power roller unit 58, in the
input and output disc units, after a plurality of parts were
assembled and before the assembly is incorporated into the housing
40, dimensions and operating conditions of the parts are
ascertained. If the dimensions and operating conditions are proper,
the parts are temporarily fixed by using appropriate tools.
Accordingly, in a condition that the toroidal type continuously
variable transmission is provided by assembling these units, the
operating conditions of the parts can be made optimum.
Incidentally, surfaces of the parts constituting these units are
coated by rust-inhibiting oil (preservative oil). Preferably, as
the rust-inhibiting oil, designated rust-inhibiting oil which does
not deteriorate the traction oil even if the rust-inhibiting oil is
mixed with the traction oil within the toroidal type continuously
variable transmission.
[0072] FIGS. 9 and 10 show a second embodiment of the present
invention. In this embodiment, a stop tool 65 is incorporated into
the structure of the above-mentioned first embodiment, so that,
when the power roller unit 58 is transported, the pre-assembled
parts 6, 22, 27, 28, 7, 8, 29, 30, 37 are prevented from being
disassembled. That is to say, among the parts 6, 22, 27, 28, 7, 8,
29, 30, 37, the parts other than the radial needle bearing 22
installed on the drive rod 37 are prevented from being disassembled
by means of stop rings 63, 64 in the assembled condition of the
power roller unit 58. The stop rings 63, 64, as they are, are
incorporated into the housing 40 constituting the toroidal type
continuously variable transmission. On the other hand, the radial
needle bearing 22 installed on the drive rod 37 is apt to disengage
from the pivot shaft 5 during the transportation. In the
illustrated embodiment, an annular stop tool 65 made of elastic
material such as rubber (for example, nitrile rubber) or synthetic
resin such as polyamide is press-fitted onto the end portion of the
pivot shaft 5 protruding from the radial needle bearing 22, thereby
preventing the radial needle bearing 22 from disengaging from the
pivot shaft 5. The other constructions and functions are the same
as those in the first embodiment. Incidentally, although the stop
tool 65 may be of disposable type, by using a re-usable stop tool,
the cost of the toroidal type continuously variable transmission
can be reduced and the resources can be saved.
[0073] FIGS. 11 and 12 show a third embodiment of the present
invention. In the second embodiment, while an example that the stop
tool 65 is prevented from disengaging from the tip end of the pivot
shaft 5 by elasticity of the stop tool 65 itself was explained, in
the third embodiment, a stop tool 65a fitted onto the tip end of
the pivot shaft 5 is prevented from disengaging from the tip end of
the pivot shaft 5 by elasticity of a stop spring 66. An inner
diameter of the stop spring 66 formed from a coil spring is
increased by manipulating grips 67 provided on both ends of the
spring so that the spring can be mounted and dismounted with
respect to the tip end of the pivot shaft 5. The other
constructions and functions are the same as those in the second
embodiment.
[0074] FIGS. 13 to 15 show a fourth embodiment of the present
invention. In this embodiment, a gear-shaped unevenness is formed
on an outer peripheral surface of a fitting projection 53a which is
formed at the end surface of the pivot shaft 5 formed on the end of
the trunnion 6 and onto which a pulley-shaped lock member for
locking a cable is to be fitted and secured and a gear-shaped
unevenness is also formed on an outer peripheral surface of a
fitting support portion 54a on which a precess cam (not shown) is
fitted and supported. However, a non-toothed portion (a recessed
portion having a width greater than those of the other recessed
portions) is formed on each of the uneven outer peripheral surfaces
of the fitting projection 53a and the fitting support portion 54a.
Further, an internal gear-shaped unevenness including one protruded
portion having a width greater than those of the other protruded
portions is formed in each of inner peripheral surfaces of the lock
member and the precess cam. Accordingly, in a condition that the
lock member is fitted on and secured to the fitting projection 53a
and the precess cam is fitted on and secured to the fitting support
portion 54a, circumferential phases of the lock member and the
precess cam with respect to the trunnion 6 and the drive rod 37 are
determined reasonably. Thus, the erroneous positioning of the lock
member and the precess cam with respect to the trunnion 6 and the
drive rod 37 can be avoided and movement of the lock member or the
precess cam in a rotational direction after the mounting can be
prevented. The other constructions and functions are the same as
those in the first embodiment.
[0075] Incidentally, the present invention can be similarly applied
to both a toroidal type continuously variable transmission of
single cavity type and a toroidal type continuously variable
transmission of double cavity type.
[0076] According to the power roller unit for the toroidal type
continuously variable transmission of the present invention, since
the unit has the above-mentioned construction, assembling
efficiency of the toroidal type continuously variable transmission
is improved, thereby reducing the cost of the toroidal type
continuously variable transmission.
[0077] Next, a fifth embodiment of the present invention shown in
FIGS. 16 to 18 will be explained. Incidentally, a characteristic of
the present invention is that a needle bearing 116 and a stop ring
119 are incorporated within an output disc 104 constituting the
toroidal type continuously variable transmission to form a unit.
Since the other constructions and functions are the same as those
in the above-mentioned conventional transmission, explanation
thereof will be omitted and the characteristic of the present
invention will be mainly described.
[0078] The output disc 104 is integrally formed by forging hard
metal such as cementation steel (blister steel) and has an inner
concave surface 104a having arc-shaped section, and a through hole
117 passing through the disc in an axial direction (left-and-right
direction in FIGS. 16 to 18) is formed in a central portion of the
disc. As shown in FIG. 18, such an output disc 104 is supported
around intermediate portion of an input shaft (rotary shaft) 115a
for rotational movement with respect to the input shaft 115a. To
this end, a needle bearing (radial rolling bearing) 116 is disposed
on an inner peripheral surface of the through hole 117. In the
inner peripheral surface of the through hole 117 an inner surface
side large diameter portion 144, a cylindrical surface portion 145,
a male spline portion 146 and an outer surface side large diameter
portion 147 are disposed from an inner surface side to an outer
surface side (from left to right in FIG. 16) and are arranged in
series with respect to the axial direction.
[0079] The cylindrical surface portion 145 is provided at an area
on the axial intermediate portion near the inner surface (near left
in FIG. 16) to serve as an outer race track of the needle bearing
116. The male spline portion 146 is adapted to engage with a female
spline portion formed on an end of a sleeve 148 (FIG. 18) disposed
around the intermediate portion of the input shaft 115a for
rotational movement with respect to the input shaft 115a, thereby
connecting the output disc 104 to the sleeve 148 for synchronous
rotational movement. Further, in a condition that the male spline
portion 146 is engaged by the female spline portion, the outer
surface side large diameter portion 147 is closely fitted onto on
an intermediate portion of the sleeve 148 nearer center than the
male spline portion 146, so that a central axis of the sleeve 148
is aligned with a central axis of the output disc 104.
Incidentally, an output gear 121a for taking out rotation of the
output disc 104 is formed integrally with the sleeve 148 on the
outer peripheral surface of the intermediate portion of the sleeve
148. The sleeve 148 is rotatably supported via a pair of ball
bearings 142 of angular type inside of a partition plate 141 within
a housing 143.
[0080] The needle bearing 116 in which plurality of needles 150 is
rollingly held by a retainer 149 is disposed within the cylindrical
surface portion 145. When assembled as the toroidal type
continuously variable transmission, rolling surfaces of the needles
150 constituting the needle bearing 116 abut against the outer
peripheral surface of the intermediate portion of the input shaft
115a acting as an inner race track. A lock groove 118 is formed
between the inner surface side large diameter portion 144 and the
cylindrical surface portion 145, and a stop ring 119 is locked
within the lock groove 118, thereby preventing the needle bearing
116 from dropping the inside of the cylindrical surface portion 145
toward the inner surface side large diameter portion 144 (toward
the left in FIGS. 16 and 17). Incidentally, engagement between the
retainer 149 and an end edge of the female spline portion 146
prevents the needle bearing 116 from dropping the inside of the
cylindrical surface portion 145 toward the inner surface side large
diameter portion 144.
[0081] An inner diameter R.sub.145 of the cylindrical surface
portion 145 an inner diameter R.sub.147 of the outer surface side
large diameter portion 147 is selected to be greater than a
diameter D.sub.146 of a circumscribed circle of a groove bottom of
the female spline portion 146 (R.sub.145>D.sub.146,
R.sub.147>D.sub.146). Accordingly, recessed grooves constituting
the female spline portion 146 can be formed in the inner peripheral
surface of the through hole 117 efficiently by a broach working,
thereby reducing the manufacturing cost of the output disc 104
having the female spline portion 146. Incidentally, a spline module
of the female spline portion 146 is preferably one or two from the
point that a thickness of the male spline portion formed on the end
of the sleeve 148 is maintained to increase torque capacity at an
engagement portion between the spline portions. The allowable
torque at the spline engagement portion is determined in dependence
upon the module, the number of teeth and lengths of the splines.
Further, desirably, an inner diameter R.sub.144 of the inner
surface side large diameter portion 144 is selected to be greater
than the inner diameter R.sub.145 of the cylindrical surface
portion 145 (R.sub.144>R.sub.145). By increasing the inner
diameter R.sub.144 of the inner surface side large diameter portion
144 in this way, the stop ring 119 can easily be locked within the
lock groove 118. A cutting length (diameter of the R.sub.145
portion) can be shortened, thereby reducing the cost.
[0082] As shown in FIG. 18, the output disc 104 provided at its
center with the through hole 117 having the above-mentioned
configuration, the needle bearing 116 comprised of the retainer 149
and the needles 150, and the stop ring 119 are pre-assembled to a
positional relation attained after the assembling of the toroidal
type continuously variable transmission is completed, before these
parts are assembled to the toroidal type continuously variable
transmission. In a condition that these members 104, 149, 150, 119
are assembled as shown in FIG. 16, it is ascertained whether these
constructural parts 104, 149, 150, 119 are operated correctly or
not, before these constructural parts 104, 149, 150, 119 are
incorporated into the housing 143 as shown in FIG. 18. After it is
ascertained that these parts are operated correctly, the output
disc unit is incorporated into the housing 143 together with other
constructural parts, thereby completing the toroidal type
continuously variable transmission. Accordingly, the positional
relation between the constructural parts can be maintained with
high accuracy to enhance efficiency and endurance of the toroidal
type continuously variable transmission without troublesome
operation such as disassembling and re-assembling of the toroidal
type continuously variable transmission. Incidentally, in the
condition that the constructural parts 104, 149, 150, 119 are
assembled to obtain the output disc unit as shown in FIG. 16,
surfaces of the constructural parts are coated by rust-inhibiting
oil. Preferably, as the rust-inhibiting (preservative) oil,
designated rust-inhibiting oil which does not deteriorate the
traction oil even if the rust-inhibiting oil is mixed with the
traction oil within the housing 143.
[0083] As shown in FIG. 18, in the condition that the constructural
parts are incorporated into the housing 143 to obtain the toroidal
type continuously variable transmission, two or three power rollers
108 (FIGS. 21 and 26) are interposed between the inner surfaces
104a of the output discs 104 and the inner surfaces of the input
discs 102A, 102B. In case where the number of the power rollers 108
interposed between the inner surfaces 104a, 102a is two, when the
power is transmitted from the input discs 102A, 102B to the output
discs 104, the inner peripheral surface configurations of the
through holes 117 formed in the output discs 104 at the centers
thereof are elastically deformed in elliptical shapes. Regardless
of such deformation, in order to prevent excessive load (edge load)
from acting on ends of the rolling surfaces of the needles 150
constituting the needle bearing 116, preferably, needles having
rolling surfaces subjected to great crowning are used as the
needles 150.
[0084] FIG. 19 shows a sixth embodiment of the present invention.
In this embodiment, when the-power is transmitted from the input
discs 102A, 102B to the output discs 104, deformation of the output
discs 104 is suppressed to maintain the endurance of the output
discs 104. That is to say, when the power is transmitted, the
output discs 104 are subjected to great thrust load from two or
three power rollers 108 (FIGS. 21 to 26). Although the output discs
104 are elastically deformed repeatedly by such thrust load, if an
amount of elastic deformation is increased, it is difficult to
ensure the endurance of the output discs 104. Particularly, when
the toroidal type continuously variable transmission is operated
under a speed reduction condition, the peripheral surfaces 108a of
the power rollers 108 abut against outer peripheral areas of the
inner surfaces 104a of the output discs 104. Regarding the
thickness of the output discs 104 along the axial direction, the
outer peripheral areas are thinnest, so that the outer peripheral
areas are apt to be deformed greatly during the operation under the
speed reduction condition.
[0085] In the illustrated embodiment, as is in the construction
shown in FIG. 26, the toroidal type continuously variable
transmission is so constructed that a partition wall 141 (FIGS. 18
and 25) is not provided between the pair of output discs 104 and
outer peripheral areas of both side surfaces of an output gear 121b
provided on the outer peripheral surface of the intermediate
portion of the sleeve 148 abut against outer peripheral areas of
the outer surfaces of the output discs 104, so that elastic
deformation of the outer peripheral areas of the output discs 104
is suppressed. That is to say, the outer and inner peripheral areas
of the outer surfaces of the output discs 104 and the outer and
inner peripheral areas of the side surfaces of the output gear 121b
are situated in a single plane perpendicular to the input shaft
115a so that these areas abut against each other. Accordingly, not
only inner diameter side areas of the outer surface of the output
shafts 104 are backed up by the output gear 121b, but the thinnest
areas (in the axial direction) (corresponding to bottoms of the
arc-shaped inner surfaces 104a) of the output discs 104 are
supported by the output gear 121b. Accordingly, even when the
thickness of the output discs 104 are not increased particularly,
during the operation of the toroidal type continuously variable
transmission, the elastic deformation of the output discs 104 can
be suppressed to ensure the endurance of the output discs 104.
Therefore, weight of the toroidal type continuously variable
transmission can be reduced and the endurance thereof can be
maintained.
[0086] FIG. 20 shows a seventh embodiment of the present invention.
Also in this embodiment, as is in the above-mentioned sixth
embodiment, when the power is transmitted from the input disc 102
to the output disc 104, deformation of the output discs 104 is
suppressed to maintain the endurance of the output discs 104. In
case of the sixth embodiment, while an example that such
arrangement is applied to the toroidal type continuously variable
transmission of so-called double cavity type in which two input
discs 102A, 102B and two output discs 104 are provided was
explained, in this embodiment, such arrangement is applied to the
toroidal type continuously variable transmission of so-called
single cavity type in which one input disc 102 and one output disc
104 as shown in FIG. 23 are provided. Thus, in this embodiment,
outer peripheral areas of an output gear 121c has wider portions,
and one side surface of the outer peripheral area (left side
surface in FIG. 20) abuts against a portion of the outer surface of
the output disc 104 corresponding to a bottom of the arc-shaped
inner surface 104a.
[0087] According to the output disc unit for the toroidal type
continuously variable transmission of the present invention, since
it is constructed as mentioned above, the cost of the toroidal type
continuously variable transmission can be reduced by improving the
assembling efficiency of the toroidal type continuously variable
transmission.
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