U.S. patent number RE33,278 [Application Number 07/295,289] was granted by the patent office on 1990-07-31 for continuously variable transmission and torque retaining differential.
Invention is credited to Edward W. Johnshoy.
United States Patent |
RE33,278 |
Johnshoy |
July 31, 1990 |
**Please see images for:
( Certificate of Correction ) ** |
Continuously variable transmission and torque retaining
differential
Abstract
A fully geared continuously variable transmission controls
output ratios of differentiating gear sets by using a control gear
set that is controlled as to rotation speed by a variable speed
drive. The ratio gear sets can be bevel gear differentiating
clusters or planetary gear sets. As disclosed, the transmission may
have two sets of ratio control gears driving separate output shafts
that are coupled to rotatable worms engaged with a worm gear to
control differentiation between the output shafts which are used as
drives for two wheel or four wheel drive vehicles at selected
engine idle rpm the variable speed drive rotates the control gears
at a selected speed and directs rpm, that holds the output shafts
at 0 rpm. As engine rpm is increased to selected cruising final
drive ratio the variable speed drive rpm is decreased
proportionately to zero to change the output drive ratio
continuously as a function of a selected parameter.
Inventors: |
Johnshoy; Edward W. (Mentor,
MN) |
Family
ID: |
26969033 |
Appl.
No.: |
07/295,289 |
Filed: |
December 30, 1988 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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881827 |
Jul 3, 1986 |
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Reissue of: |
27215 |
Mar 17, 1987 |
04784017 |
Nov 15, 1988 |
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Current U.S.
Class: |
475/6; 475/5;
475/7; 475/9; 74/665T |
Current CPC
Class: |
F16H
3/72 (20130101); Y10T 74/19116 (20150115) |
Current International
Class: |
F16H
3/72 (20060101); F16H 3/44 (20060101); F16H
037/06 (); F16H 001/40 () |
Field of
Search: |
;74/665A,665B,665C,665T,715,710,713,674,675,793 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Other References
Lamm, Michael; "Get Ready for a New Kind of Automatic
Transmission," Popular Mechanics, Jun. 1984, pp. 70-71,
105-108..
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Primary Examiner: Wright; Dirk
Attorney, Agent or Firm: Kinney & Lange
Parent Case Text
CROSS REFERENCE TO RELATED APPLICATION
This application is a continuation-in-part of my copending
application Ser. No. 881,827, still pending, filed July 3, 1986 for
TORQUE RETAINING AND PROPORTIONING DIFFERENTIAL DRIVE ASSEMBLY.
Claims
What is claimed is:
1. A variable ratio transmission comprising:
first and second gear clusters;
means to rotatably mount the gear cluster.Iadd.s .Iaddend.about
separate, parallel mounting axes for independent rotation relative
to each other;
each of said gear clusters comprising a plurality of rotatable
gears including an input gear rotatable about an axis coincident
with its respective mounting axis, an output shaft, output gear
means for driving the output shaft, and control gear means to
effect a driving connection between the input gear and the output
shaft through the output gear means;
means for simultaneously driving the input gears of both gear
clusters.Iadd.; .Iaddend.and
means for selectively and simultaneously controlling rotation of
both of the gear clusters to simultaneously vary the effective
ratio of rotation between the input gear and output shafts of both
clusters through the output gear means of the clusters.
2. The transmission of claim 1 wherein said means for selectively
controlling rotation of the gear clusters comprises variable speed
motor means.
3. The transmission of claim 1 wherein the output shaft, the output
gear means and the input gears of each cluster are coaxial.
4. The transmission of claim 1 wherein the input gear and output
gear means of both clusters comprise bevel gears, said output gear
means of both clusters comprising spider gears mounted on radial
shafts fixed to the respective output shaft.
5. The transmission of claim 2 wherein said gear clusters both
comprise planetary gear clusters, the control gear means carried on
the respective clusters comprising gear teeth that engage a further
gear to control rotation of the respective gear cluster.[.s.]. and
vary the ratio between the input gear and the output gear means of
that cluster.
6. The apparatus as specified in claim 3 wherein said input gear,
said output gear means and said control gear means of both clusters
comprises spur gears that are mounted on the same axis as the
respective output shaft.
7. The apparatus as specified in claim 1 wherein said means for
controlling rotation of the gear cluster.Iadd.s .Iaddend.comprises
gear tooth means on the clusters and a separate control gear
engaged with said gear tooth means of both cluster.Iadd.s
.Iaddend.and independently driven by a variable speed motor.
8. A variable ratio transmission having a torque proportioning
output comprising a common power input shaft driving a pair of
substantially identical variable ratio transmissions and a pair of
output shafts, a separate output shaft driven by each of the
transmissions, each of said transmissions comprising:
a gear cluster.[.,.]. .Iadd.; .Iaddend.
means to rotatably mount the gear cluster about a separate first
axis generally parallel to the first axis of the other
transmission.[.,.]. .Iadd.; .Iaddend.
a plurality of rotatable gears .Iadd.supported on a gear housing
.Iaddend.including an input gear rotatable about an axis coincident
with the first axis, output gear means for driving one output
shaft, and first control gear means carried on the gear housing to
effect a driving connection between the input gear and output shaft
through the output gear means.[.,.]. .Iadd.; .Iaddend.
means for selectively controlling rotation of the gear housing to
vary the effective ratio of rotation between the input gear and
output shaft through the output gear means.[.,.]. .Iadd.;
.Iaddend.
second control gear means mounted for rotation with respect to the
output shaft, said second control gear means controlling the final
ratio to the output gear means and the output shaft with respect to
the speed of the input gear; and
means for simultaneously controlling rotation of each of the second
control gear means comprising a pair of worms, one driving each of
said second control gear means, and a worm gear common to and
engaged by both of said worms, whereby each of the worms will
rotate only when the other worm rotates in an opposite direction,
said worms and worm gear cooperating to permit rotation of one of
the second control gear means as a function of the rotation of the
other second control gear means to control differential rotation of
said output shafts.
9. The variable ratio transmission and torque proportioning drive
of claim 8 wherein said worms are each rotatably mounted on one of
said output shafts, respectively.
10. The variable ratio transmission of claim 8 wherein said means
for selectively controlling rotation of each of said gear
.[.housings.]. .Iadd.clusters .Iaddend.comprises a common variable
speed motor means.
11. The apparatus as specified in claim 8 wherein said variable
ratio transmission comprise spur gear sets arranged as planetary
transmissions, said gear housing having gear teeth therein which
engage planet gears to control rotation of the planet gears
relative to the output shaft.
12. The apparatus as specified in claim 8 wherein said variable
ratio transmission comprises bevel gear means, said output gear
means comprising spider gears mounted onto a spider fixed to said
output shaft, and a gear housing carrying a plurality of second
spider gears coupled to said first mentioned spider gears through a
common side bevel gear engaging both sets of spider gears, and said
second control gear means comprising a further side bevel gear
engaging the second set of spider gears.
13. A variable ratio transmission having an output shaft and
comprising:
a gear cluster.Iadd.; .Iaddend.
means to rotatably mount the gear cluster about a first axis;
a plurality of rotatable gears including a bevel gear comprising an
input gear rotatable about an axis coincident with the first axis,
output gear means comprising beveled gears arranged as spider gears
mounted on radial shafts fixed to the output shaft for driving the
output shaft, and control.[.s.]. gear means carried on the gear
cluster .Iadd.to .Iaddend.effect a driving connection between the
input gear and output shaft through the output gear means;
a second set of bevel gears carried by a gear housing which
controls the ratio of drive between the input gear and output gear
means, said second set of bevel gears being rotatably mounted on
the gear housing on axes radially extending with respect to the
output shaft and said gear housing surrounding .[.the.]. .Iadd.a
.Iaddend.second set of bevel gears; and
means for selectively controlling rotation of the gear housing to
vary the effective ratio of rotation between the input gear and
output shaft through the output gear means.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention.
The present invention relates to continuously variable drive trains
especially useful with torque proportioning differential
drives.
2. Description of the Prior Art.
Various work has been carried out on continuously variable
transmissions that provide higher gas mileage, and better
acceleration than conventional automatic transmissions, without any
bumps or jerks when shifting. Many of the continuously variable
transmissions (CVT) are now on sale, and in the June, 1984 issue of
Popular Mechanics, in an article entitled "Get Ready For a New Kind
of Automatic Transmission," by Lamm, pp. 70, 71, 105-108, a
discussion of such transmissions is presented and a cutaway
illustrative showing of a transmission used by Fiat is included.
Further, the v-belt type transmission used by Volvo is illustrated
in the article.
The desirability of torque retaining and proportioning differential
drives also has been recognized, and combining continuously
variable transmission with a torque retaining and proportioning
differential drive assembly provides not only smooth operation, but
insures that the torque that is transmitted through the
continuously variable drive train will be proportioned to the
appropriate wheels.
SUMMARY OF THE INVENTION
The present invention relates to a continuously variable
transmission that utilized a simple controlled gear system for
permitting varying the output drive ratio of differential or
planetary gearing as a function of engine speed, load or even as a
function of manual signals, in a relatively low-cost assembly. An
external motor is used for controlling the final drive ratio, and
actually controls the relationship of a final gear cluster housing
that can be either a bevel gear cluster or a planetary gear
cluster, so that instead of having a fixed final drive ratio, the
ratio can be varied, depending upon the changes that are put in by
the drive for the gear housing.
The concept of providing the continuously variable output drive
train is applicable to a wide variety of output differentials but
is particularly adapted for use with a torque proportioning
differential drive. The continuously variable transmission can be
applied to either a single intermediate differentiating gear
assembly, or can be applied to a mid-differential when four-wheel
drive operations are desired. The continuously variable
transmission also can be used without a differential drive, as for
a drive transmission for small vehicles such as motorcycles, ATV's
or snowmobiles, if desired, and of course by varying the gear
ratios of the drive gears, substantially any desired relationship
can be arrived at for adequate torque carrying capacity and final
drive ratio.
When used with the torque proportioning differential drive, as
disclosed herein, the assembly is compact, provides very
substantial control over the operation of the vehicle.
The gear drive eliminates the problems that are inherent in use of
belt drives as in some of the other continuously variable
transmissions, and yet gives the advantages of being simple, and
easier to manufacture and to repair than conventional automatic
transmissions which have become highly complex in recent years,
especially the new models with lock-up torque converters, four
speeds and overdrive gearing. The disclosed continuously variable
transmission can be made very compact, so it takes up less space
than today's typical automatic transaxle, and it is lighter weight
because of its simplicity and compactness.
The continuously variable transmission can be stepless, so that no
jerks are noticed as it moves through an infinity of gear drive
ratios, and it can deliver better fuel mileage or economy than a
conventional automatic transmission. It can carry a great span of
gear ratios and can be operated or controlled by existing
microprocessors now used on automobiles, and which also have a
plurality of sensor inputs relating to sensed engine speed, load,
torque and other operating factors.
The torque retaining and proportioning differential drive assembly
with which the continuously variable transmission is disclosed as
operable, utilizes a pair of output shafts from the gear train
which are coupled through worms on each of the output shafts, which
are joined or coupled through a single worm gear, which will
control the differential rotation between the output shafts as a
function of torque. The torque retaining and proportioning drive
will prevent the torque thrust from one of the output drive shafts
that has greater torque load from speeding up the power shaft on
the poor traction or low torque output side during both
differentiating and non-differentiating drive. Yet, it will permit
differential drive needed during turning an automobile, and at the
same time will provide the continuously variable gear ratio
function for the output shafts.
The gear drive assemblies shown in this application can be made
compact and use standard gear components, bearings and the like.
The control motor can be a reversible high torque electric motor,
such as that shown in the August, 1986 Popular Science at page 78,
as being made by Unique Mobility of Denver, Colo. Additionally,
hydraulic control motors can be used, as well.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side elevational view of a schematically shown engine
and transmission, and showing a rear drive torque proportioning
differential arrangement with parts in section and parts broken
away;
FIG. 2 is a top part sectional view of the differential and rear
drive of FIG. 1;
FIG. 3 is a sectional view taken along line 3--3 in FIG. 1;
FIG. 4 is an enlarged view of the differential portion of FIG. 2
with parts in section and parts broken away;
FIG. 5 is a sectional view taken on line 5--5 in FIG. 4;
FIG. 6 is a top plan sectional view of a modified differential such
as that shown in FIG. 1 including a continuously variable
transmission gear arrangement made according to the present
invention, and;
FIG. 7 is a sectional view thereof taken as on generally a long
line 7--7 of FIG. 6;
FIG. 8 is an isometric view of the device shown in FIG. 6;
FIG. 9 is a modified top plan sectional view of a second form of
the continuous variable transmission utilizing planetary gearing
for the gear set;
FIG. 10 is a sectional view thereof taken substantially on line
10--10 in FIG. 9;
FIG. 11 is an isometric view of the device of FIG. 9;
FIG. 12 is a side sectional view of a further modified form of the
invention showing a split planetary drive for a single output shaft
application;
FIG. 13 is a schematic front sectional view thereof taken
substantially on line 13--13 of FIG. 12;
FIG. 14 is a side elevational view similar to that of FIG. 12, and
showing a further modified planetary continuously variable
transmission made according to the present invention; and
FIG. 15 is a still further modified form of the invention utilizing
a single output shaft with a single planetary drive.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The torque proportioning differential drive shown in a simplified,
two-wheel drive embodiment is illustrated in FIGS. 1-5.
The torque proportioning differential drive as will be shown uses
parallel, independent output shafts which drive the rear or front
wheels independently, so that there are parallel power paths where
the power is divided for the final drive. In an embodiment used in
connection with four wheel drive vehicles the torque proportioning
differential is used in a mid-differential drive for driving
forward and rear differentials that then drive the axles to the
drive wheels. As shown in FIG. 1, an engine and transmission
indicated schematically at 15 has a transmission output shaft 16
that is a normal drive output shaft from a transmission having
suitable gear ratios. The engine and transmission can be
conventional, either manual shift or automatic, and the output
shaft 16 has a spur gear 17 drivably mounted thereon, which in turn
will drive the output drive components. In the embodiment shown in
FIG. 1, it is to be understood that the intermediate gear
assemblies can be modified to obtain the desired gear ratios, and
may not even be used if desired so that a direct drive to the
differential components can be made from the transmission output
shaft. Intermediate gear cases may be used, if desired, as
well.
However, as shown, a spur gear drive, which can have
interchangeable size gears, is shown generally at 20 and it is
fixed to the transmission housing. The term spur gear is intended
to include gears with angled teeth or actual helical teeth on the
gears, but with parallel mounting shaft axes, as gears are now made
for noise reduction. The gear drive 20 has an outer housing 21 that
mounts a first idler gear 22 that meshes with gear 17 and rotates
on its outer periphery as shown in FIG. 1 in direction of the arrow
22A. This gear is suitably mounted on a shaft that rotates in
bearings in the housing 20 in a conventional manner.
Gear 22 in turn drives a spur gear 23 that is drivably mounted onto
a drive shaft 24. The drive shaft 24 is mounted on suitable
bearings 25 in the gear case 21, and also passes through the rear
wall of this gear case 21 and through a forward wall 27 of a
differential drive gear case indicated generally at 26. The forward
wall 27 of the gear case 26 has suitable bearings for mounting the
shaft 24, and as stated the gear 23 drives the shaft 24 which in
turn is driven through a spline or suitable member to drive a spur
gear 30 (see also FIG. 3) that is mounted inside the differential
housing 26. The spur gear 30 as shown in this form of the invention
is at the lower side of the differential housing 26. Gear 23 is
rotated in direction that is indicated by the arrow 31 (FIG. 1),
and gear 30 thus also rotates in this same direction as indicated
by the arrow 32. Arrow 32 is also shown in FIG. 3.
The gear 30 as shown in FIG. 3 drives a pair of power dividing spur
gears 35 and 36, respectively. The spur gears 35 and 36 comprise
power input gears to a pair of differential bevel gear drive
clusters indicated generally at 37 and 38 (FIG. 2), respectively.
These drive clusters 37 and 38 are identically constructed, as are
the differential drive gear clusters in other forms of the
invention, but in this form of the invention the gears will be
separately numbered, even though they operate in precisely the same
manner for the output drive.
The first input drive spur gear 35 is splined onto, or otherwise
drivably attached to a first bevel gear 41 forming a portion of the
differential drive cluster 37. The bevel gear 41 and its spur gear
35 are rotatably mounted onto a first output shaft 42 which is of a
pair of parallel drive shafts. The shaft 42 comprises one of the
parallel power paths that is used with the torque proportioning
differential drive.
The gear 36 in turn is splined or otherwise drivably attached to a
bevel gear 43 (FIG. 2). The spur gear 36 and bevel gear 43 are both
rotatably mounted onto a second of the parallel drive shafts
indicated at 44. The output drive shafts 42 and 44 are identically
constructed as well.
The rotatable mounting of the spur gear and bevel gear set 35 and
41 for the cluster 37 on shaft 42 and the spur and bevel gear set
36 and 43 for the cluster 38 on shaft 44 shows there is no drive
directly from these gears to the parallel output shafts 42 and
44.
The shafts 42 and 44 have first end portions rotatably mounted on
suitable bearings 45 and 46 in the front wall 27 of the
differential housing or case 26. The bearings 45 and 46 preferrably
are tapered roller bearings that take both end thrust and radial
loads, although the bearings are shown only schematically. The
shafts 42 and 44 have output end portions rotatably mounted in
suitable bearings 51 and 52, respectively at the rear wall 53 of
the differential case. These bearings also can be taper roller or
similar bearings that carry both thrust and radial load.
The shafts 42 and 44 each include spiders of four radial shafts or
cross shafts fixed to shafts 42 and 44 to rotatably support spider
bevel gears, as perhaps best seen in FIG. 2. The radial shafts or
cross shafts on shaft 42 are shown at 42A and each are 90.degree.
from adjacent shafts. The parallel output shaft 44 has radial
shafts or cross shafts 44A thereon.
FIGS. 3 and 4 show the details of the gear clusters 37 and 38, and
the positioning of the radial or cross shafts holding the
differential drive orbiting spider bevel gears.
In the gear cluster 37, four orbit spider bevel gears 55 are
mounted onto the respective cross shafts 42A on suitable bearings,
so that the bevel gears are freely rotatable on the cross shafts
42A. These bevel gears 55 are held in place with suitable snap
rings on the cross shafts, and engage the bevel gear 41. Further,
the gear cluster 37 includes a control bevel gear 57 rotatably
mounted on the shaft 42 on an opposite side of the cross shafts
from gear 41 and engaging the bevel gears 55. This control bevel
gear 57 is controlled to be nonrotatable except when differential
speeds are required. Thus, normally as the bevel gear 41 is
rotated, the gears 55 are driven to orbit around the gear 57 and
thus drive the shaft 42 through the radial shafts or cross shafts
42A. The shaft 42 is thus rotated at a different speed from the
input bevel gear 41 determined by the rotation of the control bevel
gear 57. The gear cluster 37 provides a gear ratio of 2:1, that is
the output shaft 42 rotates at one-half of the rotational speed of
the gear 41 where gear 57 is held.
It can therefore be seen that by controlling the gear 57 so that it
is held or rotates at a controlled rate, and in a selected
direction relative to the direction of rotation of gear 41 the
output speed of the shaft 42 can be likewise controlled and
changed.
The gear cluster 38 operates in the same way as explained for the
gear cluster 37, and includes orbiting spider bevel gears 65
mounted onto the cross shafts 44A, and a control bevel gear 67 that
is rotatably mounted on the output portion of the shaft 44. The
control bevel gear 67 is normally held from rotation until
differential output speeds of shafts 42 and 44 are required. The
gear 67 is controlled in the same way as gear 57.
The control bevel gears 57 and 67 are controlled through the use of
a worm and worm gear assembly indicated generally at 70 that
provides proportioning of torque between the parallel power paths
including the shafts 42 and 44 and as controlled by the
differentiating gear clusters 37 and 38.
Reference is made specifically to FIGS. 4 and 5, wherein the worm
gear assembly 70 includes a worm (a spiral gear) 71 that is
rotatably mounted on suitable bearings 72 on the shaft 42, and
which in turn is splined as at 73 to the hub of the control gear
57. Thus, worm 71 becomes a member that is drivably coupled to the
control gear 57 and controls rotation of the gear 57. The worm 71
engages a worm gear 75 which is rotatably mounted on a shaft 76
that is suitably supported in the differential housing 26, as shown
in FIG. 5. The worm gear 75 is mounted on a suitable bushing 77,
and the axis of the shaft 76 is perpendicular to the axes of shafts
42 and 44.
A second worm 78 is rotatably mounted on the shaft 44 on suitable
bearings 79, and is splined as at 80 to the hub of the control gear
67 for the second gear cluster 38. The worm 78 also engages the
worm gear 75, on a diametrically opposite side of the worm gear
from worm 71.
The torque proportioning feature involves the worm gear 75
operating in the gear assembly 70 to engage the two worms 71 and
78. The differential drive operates on the principle that the worm
gear cannot drive a worm, but worms can drive a worm gear. Thus it
is immediately apparent that the first worm 71 will be prevented
from rotation by the worm gear 75 unless the worm 78 is rotating in
an opposite direction, and vice versa. That is, the worm 78 will be
prevented from rotating unless the worm 71 is rotating in an
opposite direction so that the worm gear 75 can rotate on the shaft
76.
The helical angle of the worm can be in the range of 12 to 30
degrees, with the angle of the worm gear being the complement of
this angle. The selection of the helix angle is well within the
skill of the art and can be based on engineering design
decisions.
The output power in the two parallel power paths defined by shafts
42 and 44 is transmitted by the shafts 42 and 44 through suitable
universal or constant velocity joint assemblies shown at 85 and 86,
respectively, to input shafts 87 and 88 of a final rear axle drive
housing 89 (as shown in FIGS. 1 and 2). Two separate bevel gear
sets 90 and 91 are mounted in the housing 89, to in turn drive the
output axles 92 and 93 in a conventional manner.
The axle shafts 92 and 93 are connected to lateral axle shafts that
in turn drive the wheels of a vehicle (not shown) in a normal
way.
It can be seen that under normal conditions, one of the axle shafts
92 or 93 cannot turn independently of the other, because they come
from a common drive and the control gears 57 and 67 are normally
held, and only when the worms 71 and 78 are rotating in opposite
direction so that the worm gear 75 can rotate, will differential
rotational speed of the output shafts be possible.
In FIG. 6, a modified differential drive apparatus is illustrated,
and the operation is substantially the same as that insofar as the
differentiating and torque proportioning of the output shafts is
concerned, but in this form of the invention, a variation is made
in that it is formed as a mid-differential for four-wheel drive
unit, and includes one output shaft that drives rearwardly and
another output shaft that drives forwardly for front-wheel drive.
In this form of the invention, torque proportioning differential is
operationally identical with that shown in FIGS. 1-5 and would be
connected to the respective output shafts, one for front-wheel
drive and one for rear-wheel drive, and each driving an output
differential which would have two output shafts to drive the
respective axles. This arrangement is only schematically shown in
FIG. 6. However, the concept of the arrangements for front and
rear-wheel drives is shown in the previously mentioned application
of which this is a continuation-in-part. It is to be understood
that the continuously variable ratio transmission construction can
be used with any type of differential drive, if desired, but that
it is particularly useful with the torque proportioning output
differentials for two or four-wheel drive vehicles.
In this form of the invention, an engine indicated schematically at
95 drives a lock-up torque converter 97 which has an output shaft
96 that drives a planetary control gear set 94 of conventional
design to provide neutral, drive, reverse and park functions. The
planetary control 94 drives an input shaft 98 for the disclosed
continuously variable ratio transmission and mid-differential
having a case or housing 106.
The input shaft 98 is at the lower portion of the case or housing
106, and has a spur gear 110 drivably mounted thereon that drives a
pair of power dividing spur gears 115 and 116, respectively. Gear
110 is splined or otherwise driven by the shaft 98, for example,
with Woodruff keys or the like. The drive between the shafts and
gears shown herein are conventional, and if not specifically
mentioned may be splines or keys. Spur gears 115 and 116 comprise
power input gears to a pair of drive control gear sets or clusters,
indicated generally at 117 and 118, respectively. The gear sets or
clusters 117 and 117 are bevel gear sets and are constructed
similarly to the sets shown in FIGS. 1-5, except that in this form
of the invention the continuously variable transmission features
are added to a following gear cluster arrangement. However, in this
form of the invention, the input drive spur gear 115 is splined
onto or otherwise drivably attached to a first bevel gear 121 which
is rotatably mounted onto a first output shaft 122. This output
shaft 122 extends forwardly in this form of the invention, through
a front wall 107 of the case 106, and shaft 122 is one of a pair of
parallel output or drive shafts. This is one of the parallel power
paths that is used with the torque proportioning differential
drive, and with the disclosed continuously variable transmission.
The gear 116 is splined or otherwise drivable attached onto a bevel
gear 123, and the gear 116 and bevel gear 123 are both rotatably
mounted onto a second of the parallel output or drive shafts
124.
The drive shafts 122 and 124 each are suitably mounted on bearings
125 and 126, respectively, in the front wall 107 of the case 106,
and bearings 131 and 132 at the rear wall 133 of the case. As can
be seen, the bearing 126 supports an end of the shaft 124, and the
bearing 131 supports an end of the shaft 122, and the shafts extend
in opposite directions out of the case 106.
The shafts 122 and 124 each include spiders comprising four radial
shafts or cross shafts fixed to the respective shafts 122 and 124
to rotatably support spider bevel gears, similar to that shown in
FIG. 2, and as also can be seen schematically in FIG. 8. The four
spider or cross shafts on the shaft 122 are indicated at 122A, and
each are 90.degree. from the other. The shaft 124, which is for the
rear torque proportioning differential drive, has radial shafts or
cross shafts 124A thereon. In the bevel gear cluster or set 117
that comprises a drive control gear set, there are four orbit or
spider bevel gears 135 mounted onto the shafts 122A on suitable
bearings. The bevel gears 135 are freely rotatable on the cross
shafts 122A. These bevel gears 135 are held in place with suitable
snap rings on the cross shafts and engage the bevel gear 121.
The drive gear set or cluster 117 also includes a control bevel
gear 137 which is a double-faced bevel gear, having gear teeth 137A
and 137B, so the gear 137 is common to the cluster 117 and a second
ratio control gear set that will be explained. The bevel gear 137
is rotatably mounted on the shaft 122, on suitable bearings or
bushings.
The bevel gear set or cluster 118 includes orbiting spider bevel
gears 145 rotatably mounted on the cross shafts 124A, and includes
a control bevel gear 147 which also is a double-ended or common
bevel gear having teeth 147A engaging gears 145 and teeth 147B
engaging a second control gear cluster mounted in series with the
first cluster 118. Gear 147 is rotatably mounted on the shaft
124.
The rotation of the gears 137 and 147, when controlled, either for
proportioning torque through a torque proportioning worm gear
assembly similar to that shown in FIGS. 1-5, or when being
controlled to provide a continuously variable gear ratio,
determines the output drive ratio between the input bevel gears 121
and 123 and the output shafts 122 and 124. The control bevel gears
137 and 147 comprise side gears for second gear ratio control gear
sets or clusters 157 and 158, respectively. These second gear
clusters are also differentiating bevel gear sets, but operate in a
different manner to provide for continuously varying the output
gear ratio between the input side bevel gears 121 and 123 and the
output shafts 122 and 124. This ratio control is done through two
separate controls, one for differential drive and the other for a
variable output drive ratio.
As can be seen the gear cluster 157 includes a control gear housing
assembly 159, that comprises a central hub or spider 160 that is
rotatably mounted on shaft 122 with suitable bearings. The spider
hub 160 has spider shafts 170A positioned at 90.degree. from each
other and extending radially outwardly therefrom. The spider shafts
170A in turn mount bevel spider or orbit gears 165 thereon that
engage the second section or gear teeth 137B of the side gear 137
and which are rotatably mounted onto the spider shafts 170A. The
spider shafts 170A have outer end tongues or lugs 170B that have
parallel sides and over which a ratio control gear drive housing
section 163 is drivably mounted. The drive housing section 163 is
an annular ring type housing that surrounds the spider hub 160 and
shafts 170A, and which has a central opening that is of size to fit
over the spider gears 165.
The outer surface of the gear housing section 163 is provided with
spur gear teeth 164, that extend all the way around the
housing.
Additionally, the ratio control gear cluster 157 includes a
differential control bevel gear 167 that operates in substantially
the same manner as the control bevel gear 57 shown in FIGS. 1-5.
The control bevel gear 167 is normally held stationary, as was
previously explained, except during torque proportioning or
differentiating drive that can occur through the control for the
bevel gear 167 to permit differential movement between the shafts
122 and 124.
The ratio control gear cluster 150 includes a central spider hub
170 that has spider shafts 170A, which together make a spider
assembly 171 that is rotatably mounted onto the shaft 124 through a
suitable bushing or bearing. The spider shafts 170A have spider or
orbit bevel gears 175 rotatably mounted thereon which are adapted
to engage the gear portion 147B of the side or control gear 147.
The spider gears 175 will rotate on the spider shafts 170A whenever
necessary because of the loads and control functions required.
The spider shafts 170A have tongues or lugs 170B which receive
slots on the interior opening of a gear drive housing 173 that
surrounds the spider assembly 171, and which can be used for
controlling motion of the spider assembly about the shaft 124. The
outer periphery of the control gear housing 173 has spur gear teeth
174 thereon.
The gear set or cluster 158 has a control bevel gear 177 on the
output side thereof which drivably engages the gears 175, and which
is also rotatably mounted on the shaft 124. Gear 177 is normally
non-rotatable except in differential movements that will permit
differences in rotational speed between shafts 122 and 124, as was
previously explained in connection with the worm and gear drive in
FIGS. 1-5.
The ratio control gear housing sections 163 and 173 are controlled
to permit changes in rotational speed of the control gears 173 and
147, relative to the bevel gears 167 and 177 permits providing a
continuously variable ratio transmission. The control permits
continuously varying the output speed of shafts 122 and 124
relative to the speed of the input shaft 98. The rotation of the
gear housing sections 163 and 173 are controlled and adjusted
through the use of a transmission control gear and motor. As can be
seen in FIGS. 6, 7 and 8, a support shaft 180 is rotatably mounted
in the transmission case generally parallel to the shaft 98. The
shaft 180 is above the gear sets 157,158, while the input shaft 98
is on the lower side of the input gear sets or clusters, as shown
in FIG. 3. The shaft 180 has a transmission ratio control gear set
181 rotatably mounted thereon. The transmission control gear set
includes a spur gear 162 that drivably engages both of the gears
164 and 174 formed on the outside of the gear housing sections 163
and 173. The gear housing sections 163 and 173 are thus ring type
gears of the drive control gear sets or clusters 157 and 158. The
ratio control gear housing sections 163 and 173 cannot rotate
unless the gear 162 permits such movement and also rotates.
The gear 182 can control rotation of both of the drive ratio
control gear housing sections simultaneously. The gear set 181 has
a worm gear 183 splined to the hub thereof, or integrally formed
therewith, and this worm gear 183 is drivably associated with a
worm 185 that in turn is driven by the output shaft of a variable
speed, reversible motor 186 that can be either a high torque
electric motor, or if desired can be a hydraulic motor that is
suitably controlled. The motor 186, of course, will be mounted in a
suitable bracket shown schematically at 187 to the case 106 in a
conventional manner, and the output shaft of the motor can be as
long as necessary to provide the necessary clearance for the
various parts.
However, the variable gear ratio of the transmission can be
controlled positively by operating the motor 186 and gear 182 to
permit the drive ratio control gear housing sections 163 and 173 to
be rotated and thus control the output drive ratio through the
control gears or side gears 137 and 147. The ratio of drive to
shafts 122 and 124 through the associate spider gears and shaft
changes if the ratio control gears are permitted to rotate at
different speeds. The rotation of the output shafts 122 and 124
thus can be varied in relation to the speed of rotation of the
gears 121 and 123 by controlling the speed of rotation of gears 137
and 147, respectively.
The torque proportioning function between the parallel power shafts
122 and 124, which as shown are for front and rear wheel drives,
respectively, is accomplished by the use of a worm and worm gear
assembly 190 which operates in exactly the same way as the worm
gear assembly indicated at 70 in FIGS. 1-5.
The differential control gear 167 of the drive ratio control
cluster 157 as shown has a worm 191 that is shown only
schematically in section. The worm 191 is rotatably mounted on the
shaft 122 on suitable bearings or bushings, and is splined as at
193 to the differential control gear 167. The worm lead (right or
left hand) can be selected for directing the thrust in optimum
direction for good engineering design. The worm 191 engages a worm
gear 195 that is rotatably mounted on a shaft 196, which is
suitably mounted in the gear case. Because shaft 180 is positioned
above the shaft 196, the support for shaft 196 will come in
underneath shaft 180 from the rear wall of the case, or will be
made so that the shaft 180 will pass through the support.
A second worm 198 is rotatably mounted on the shaft 124 and is
splined as at 200 to the control gear 177 for the second drive
ratio control gear cluster 158. The worm 198 also engages the worm
gear 195 on a diametrically opposite side of the worm gear 195 from
the worm 191.
These worms and worm gear provide the torque proportioning and
differential drive feature, operating through assembly 190. The
differential drive operates on the principle that a worm gear
cannot drive a worm, but worms can drive worm gears. Thus, it is
apparent that the first worm 191 will be prevented from rotation by
the worm gear 195 unless the worm 198 is rotating in an opposite
direction. This works in the inverse, as well. The torque
differential caused by a tendency of one driven wheel to spin will
be resisted and drive torque will be proportioned.
As previously stated in relation to FIGS. 1-5, the helical angle of
the worms can be in the range of 12.degree.-30.degree., with the
angle of the worm gear being the complement of the worm angle. The
selection of the helix angle desired is within skill of the art,
that is, it is an engineering decision.
The torque proportioning control will thus operate so that there
can be torque proportioning between the shafts 122 and 124. A rear
drive torque proportioning differential indicated at 202 is
connected to the shaft 124 for the rear wheel drive. The
differential 202 can be the same as that shown in FIGS. 1-5. The
differential 202 will drive an axle assembly indicated at 203 that
is also identical to that shown in FIGS. 1-5.
Additionally, the output shaft 122 drives a torque proportioning
differential 205 that would be the same as that shown in FIGS. 1-5
of the present invention except the direction of rotation would be
selected to be appropriate for front-wheel drive, and the lead
angle of the torque proportioning control worms could be changed to
direct thrust from the worms in proper direction, which in turn
will drive a front axle 206 that can be constructed to have
steering and constant velocity joints connected to the individual
wheels of the vehicle to permit the vehicle to be steered.
The transmission ratio control motor 186 is controlled by suitable
controls 210 that can be microprocessor on, off, directional and
speed adjustment controls responsive to input sensors such as rpm
or speed sensors 211, sensing the engine speed. The control 210
provides signals to drive the motor 186 in either direction of
rotation and to vary the speed as desired, so that the output drive
ratio can be changed. It can immediately be seen that by varying
the rates of rotation of the drive ratio control gear housing
sections for the drive ratio gear sets, the variation in the drive
ratio between the input rpm of shaft 98, and the output rpm's of
shafts 122 and 124, which comprise the parallel output power
shafts, can be changed as desired, and by suitable sensors a smooth
change in drive ratio can be achieved from a low gear effect to a
straight through or overdrive effect.
In the form shown, with the motor 126 stopped to hold stationary
the ratio control gear housing sections through the worm-worm gear
arrangement, the output drive ratio is two-to-one, that is, the
output shafts 122 and 124 will be rotating at one-half of the speed
of the input shaft.
In a specific embodiment that may aid in understanding the
operation, the input spur gear, namely the gears 110, and also 115
and 116 are each 27-tooth 2.25 pitch diameter spur gears. The drive
ratio control housing section spur gears 164 and 174 have 38 teeth,
and the ratio control spur gear 182 for the drive ratio control has
22 teeth.
The side bevel gears 135, 145, 137, 147, and 167, 177 all have 27
teeth, and the orbit or spider bevel gears 135, 145, 165 and 175
all have 18 teeth.
The drive ratio control worm gear 183 has 12 teeth, and the drive
ratio control worm 185 on motor 186 is a quadruple thread
180.degree. and 26' helix. Both the worm gear and worm have
one-inch pitch diameter and provide a six-to-one gear ratio.
The torque proportioning worm gear 195 has 18 teeth with a two-inch
pitch diameter, and the worms 191 and 198 are 1.5 pitch diameter,
sextuple thread worms with a 26.degree., 34' helix. A chart of the
gear ratios follows as Chart I:
CHART I ______________________________________ Pitch Diameter Gear
No-Teeth (inches) ______________________________________ Spur Gears
110 27 2.25 115 27 2.25 116 27 2.25 164 38 3.167 174 38 3.167 182
22 1.833 BEVEL GEARS 121, 123, 137 27 2.25 147, 167, 177 135, 145,
165, 175 18 1.5 DRIVE RATIO CONTROL 183 12 1
______________________________________
The continuously variable transmission which is shown also is a
mid-differential assembly in FIGS. 6, 7 and 8 and has a drive ratio
of two-to-one. It is called a mid-differential assembly because it
provides differential control between front and rear wheel drive
differentials. Assuming, for example, that the torque proportioning
differential 202 also has a drive ratio of two-to-one (or the front
wheel drive differential also does) in an illustrative progression
of the variable ratios, as shown in Chart II below. The engine
input rpm at idle is assumed to be 600 rpm, and typical engine
speeds are illustrated.
The ratio control worm rpm is the same as the output speed of the
transmission ratio control motor 186, which speed can be controlled
by sensing the engine rpm, for example (or even manually
controlled), and this, of course, can allow infinite variations in
ratio including manual selection of mid-range drive ratios, and
selection of higher or lower engine rpms at which the final drive
ratio for cruising is reached. The drive axle rpm listed is the
speed of the output drive axle, either front or rear, the two
differentials each having two-to-one reduction ratio, provide a
four-to-one ratio to the axles so that the output shaft driving
axle assembly 203 or 206 would be one-fourth of the input rpm of
the shaft 98. The ratio between the worm and worm gear for the
transmission ratio control is six-to-one, so that the ratio control
gear 182 (called a pinion in Chart II) rotates at one-sixth of the
worm rotation, and that also is one-sixth of the rpm of the ratio
control motor 186.
CHART II ______________________________________ Ratio Control Gear
Ratio Engine Housing Control Ratio Drive Final Input RPM: Pinion
Worm Axle Drive RPM: (164, 174) RPM: (182) RPM: (185) RPM: Ratio:
______________________________________ 600 300 518 3108 0 Infinite
700 285 492.1 2952.6 32.5 21.5 800 270 466.2 2797.2 65 12.3 900 255
440.3 2641.8 97.5 9.2 1000 240 414.4 2486.4 130 7.7 1200 210 362.6
2175.6 195 6.2 1400 180 310.8 1864.8 260 5.4 1600 150 259 1554.0
325 4.9 1800 120 207.2 1243.2 390 4.6 2000 90 155.4 932.4 455 4.4
2200 60 103.6 621.6 520 4.23 2400 30 51.8 310.8 585 4.1 2600 0 0 0
650 4.0 3000 750 4.0 ______________________________________
The ground speed of the vehicle, assuming a 26 inch wheel diameter,
varies, for example, from about 10 mph at 1000 rpm and the 2600 rpm
ratio given would be approximately a 50 mph speed. A 300 rpm speed
would be approximately 57.9 mph.
It also is apparent that the ratio control worm can be replaced
with a non-slip variable speed pulley and belt, that is non-slip,
by either directly driving a worm with the belt, or replacing the
worm and worm gear with the belt and pulley arrangement. Belts also
could be used to drive ratio control housing section 167 and
174.
Again, the ratios in Chart II assume that both of the shafts 122
and 124 are rotating at the same speed and differentiation is not
required. Differential drive is an added feature.
In a modified form of the invention which illustrates the
interchangeability of the continuously variable transmission
concept with or without the torque proportioning, using a gear set
or cluster comprising a planet gear assembly is shown in FIGS. 9,
10 and 11.
In FIG. 9, an outer case 216 comprises a differential-torque
proportioning continuously variable transmission assembly that has
a forward wall 217 that supports an input drive shaft 213, that
includes an input drive spur gear 214, which in turn drives input
spur gears 219 and 220 which are rotatably mounted with respect to
the respective output shafts 222 and 224. The gears 219 and 220,
respectively, comprise input gears which drive through planetary
type gear sets, including a drive ratio control section 225 that is
associated with the output shaft 222, and a drive ratio control
section 226 that is associated with the output shaft 224. These
sections are for controlling the ratio in the continuously variable
transmission arrangement shown in FIGS. 9-11. A control gear set or
section indicated at 227 is associated with the control for
proportioning torque and for differentiation and is arranged with
shaft 222. A drive control gear set or section 228 is associated
with the shaft 224 for controlling the differential and torque
proportioning features.
The ratio control gear sets, as stated, comprise planetary gear
sets with planet gears, sun gears and planet carriers that also
comprise gear housing sections. The ratio control section 225
includes a sun gear 230 that is drivably coupled, either by
splining or making a unit, to the spur gear 219, and is rotatably
mounted relative to the shaft 222.
The sun gear 230 engages multiple planet gears (four spur gears as
shown) indicated at 231 which are rotatably mounted onto planet
shafts 232, which shafts in turn are fixedly mounted in a planet
shaft carrier 233. The shaft carrier 233 is rotatably mounted onto
the shaft 222.
The planet gears 231 also drivably engage an interior gear 235A
having spur gear teeth formed on the interior of a ratio control
planetary gear carrier housing or ring 235. An output set of planet
gears 237 are rotatably mounted on the outer ends of shafts 232
from planet gears 231.
Additionally, the gear housing 235 for the set of planet gears has
an external spur gear 240 thereon for drive ratio control purposes,
for providing the continuously variable ratio control.
The planet gears 237 drivably engage a control gear 245 (a sun
gear) that in turn is drivably mounted (keyed) on the shaft 222 as
at 247. Gear 248 has internal teeth 249 which are drivably engaged
by planet gears 237, as well. The control gear 248 and its internal
teeth 249 comprise a part of the drive control section 227. The
control gear 248 has a hub 250 that is rotatably mounted on shaft
222 and is drivably coupled to the torque proportioning worm and
worm gear differential control. The drive, when gear 248 is held
from rotation, goes from gear 219 to sun gear 230, to planet gears
231 and, if gear housing 235 is held from rotation, through shafts
232 and carrier 233 (which must rotate about shaft 222), and then
through gears 237 that react with gear 245 to drive sun gear 245
and shaft 222.
A second ratio control section 226 is identically constructed to
the section 225, and it rotates in the same direction and is
associated with the shaft 224. It includes a sun gear 260 that is
drivably connected to the input spur gear 220, and rotatably
mounted on the shaft 224. The sun gear 260 drives multiple planet
gears 261 that are rotatably mounted on planet shafts 262 that in
turn are fixedly carried by a planet shaft carrier 263 that is
rotatably mounted on the shaft 224 in suitable bushings or
bearings. The planet gears 261 also drivably engage an internal
gear 265A formed in the interior of a gear housing 265. An output
set of planet gears 267 are rotatably mounted on the shafts 262 at
opposite ends from the gears 261.
An external ratio control spur gear is formed as shown at 270 on
the exterior of the housing 265.
The planet gears 267 drivably engage a sun gear 275 which is
drivably mounted on shaft 224. This sun gear 275 drives shaft 224
and comprises an output gear. A drive control gear 278 has internal
teeth 279 which are drivably engaged by planet gears 267. The gear
278 comprises a part of the drive control section 224. The gear 278
has a hub 280 that is drivably mounted (splined) on the output
torque proportioning and differential control worm for the shaft
224.
The torque proportioning and differential control is shown
generally at 290 and comprises a first worm 291 that is drivably
mounted onto the hub 251 of the gear 248 for the drive control
section 227. The worm 291 is rotatably mounted with respect to the
shaft 222, which comprises an output shaft for a forward
differential when used with a four-wheel drive unit. A suitable
spacer or thrust washer 292 can be provided between the rear walls
of the case 216 and the worm 291, if desired.
Torque proportioning control for the shaft 224 comprises a worm 296
that is rotatably mounted on the shaft 224 and is splined with
respect to the hub 280 of the gear 278 for the drive control
section 228 that is associated with the shaft 224. This worm 296 is
spaced from the rear wall of the case 216 with a suitable thrust
washer of spacer 298.
A worm gear 299 is rotatably mounted on a shaft 300 that is
suitably supported in the gear case 216, and engages both of the
worms 296 and 291, to control differentiation or rotational
movement between shafts 224 and 222 as previously explained, and
also to permit drive and control proportioning of torque between
the two output shafts as previously explained.
The continuously variable transmission aspects of the present
invention are obtained by controlling the speeds of rotation of the
ratio control gear housing sections 235 and 265. This is done by
mounting a shaft 302 above the gear housings, in suitable bearings
(not shown) and including a ratio control drive gear assembly
indicated generally at 303 that is rotatably mounted on the shaft
302 (the shaft 302 is mounted as shown in FIG. 6, for example). The
ratio control gear 303 includes a spur gear section 304, and a
drivably coupled worm gear 305 that either can be splined to the
gear 303 or formed as a unit. The rotation of the worm gear is
controlled by a worm 306 that is drivably mounted onto a shaft 307
that comprises the output shaft of a reversible, variable speed
motor 308 of suitable design as previously explained. The motor 308
is positioned laterally of the case 216 and powered in a suitable
manner, and by regulating the speed of rotation of the motor 308,
various drive ratios can be obtained through the planetary gear
sets or clusters that can be varied in ratio as to the input and
output shaft speeds.
In the specific embodiment of FIGS. 9-11, in understanding the
operation, the input spur gears, namely the gears 214, 217 and 220,
are each 27-tooth 2.5 pitch diameter spur gears. The drive ratio
control housing section spur gears 240 and 270 have 44 teeth, and
the variable ratio control spur gear or pinion 303 for the drive
ratio control has 21 teeth.
The sun gears and planet gears 230, 231, 237, 245, 260, 261, 267
and 275 all have 12 teeth, and the internal gears 235A, 265A in the
gear housings and control gears 249 and 279 have 36 teeth.
The drive ratio control worm gear 305 has 15 teeth, and the drive
ratio control worm 306 driven by motor 308 is a quadruple thread
18.degree. and 26' helix. The worm gear 305 has a one and
one-fourth pitch diameter and worm 306 has a one-inch pitch
diameter to provide a seven and one-half to one gear ratio.
The torque proportioning worm gear 299 has 21 teeth with a 2.5 inch
pitch diameter, and the worms 291 and 296 are 1.5 inch pitch
diameter, sextuple thread worms with a 26.degree., 34' helix. A
chart of the gear ratios follows as Chart III.
CHART III ______________________________________ Pitch Diameter
Gear No-Teeth (inches) ______________________________________ Spur
Gears 214 30 2.5 220, 219 30 2.5 230, 260 12 1.0 231, 261 12 1.0
245, 275 12 1.0 237, 267 12 1.0 235A, 265A 36 3.0 249, 279 36 3.0
240, 270 44 3.66 303 21 1.75 WORM GEARS 305 15 1.25 299 20 2.5
WORMS 306 quad-thread 1.0 18*, 26' helix 291, 296 sex. thread 1.5
26*, 34' helix ______________________________________
A typical progression indicating the input rpm and the rpm of the
ratio control gears as well as the control electric motor rpm is
reproduced Chart IV that follows. Again, electronic sensing of
enginer rpm and control of the control motor rpm in other ways can
allow a large variety of variations. Gear ratios shown in FIGS. 9,
10 and 11 are set forth in Chart III, and the information of Chart
IV shows the final drive ratio.
Using the continuously variabe transmission and differential shown
in FIGS. 9-11 as a mid-differential, with a ratio of 1:1 using the
gear sizes shown, and a front and rear differential ratio of
three-to-one so that the output drive axles rotate at one-third the
speed of output shafts 222 and 224, a wide final drive ratio can be
obtained by controlling motor 308 and then the ratio of the
continuously variable transmission.
As shown, each ratio control gear housing (gears 240, 270) has 44
teeth, and ratio control pinion (spur gear 303) has 21 teeth to
give a 2.09:1 ratio. The ratio control worm (306) to worm gear
(305) ratio is 7.5:1.
CHART IV ______________________________________ Ratio Control Gear
Ratio Ratio Engine Housing Control Worm Drive Final Input RPM:
Pinion RPM: Axle Drive Speed RPM: (240, 270) RPM:(303) (306) RPM:
Ratio MPH: ______________________________________ 600 200 418 3135
0 Infinite 0 700 186.66 390.38 2928 46.67 15.0:1 3.6 800 173.33
362.5 2719 93.34 8.57 7.2 900 160 334.6 2510 140 6.43 10.8 1000
146.66 306.7 2300 186.67 5.36 14.4 1100 133.33 278.8 2091 233.34
4.71 18.0 1200 120 250.9 1882 280 4.29 21.6 1300 106.65 223.1 1673
326.7 4.0 25.2 1400 93.33 195.2 1464 373.34 3.75 28.9 1500 80 167.3
1254 420 3.57 32.5 1600 66.66 139.4 1045 466.67 3.43 36.1 1700
53.33 111.5 836 513.34 3.31 39.7 1800 40 83.6 627 560 3.21 43.3
1900 26.66 55.75 418 606.66 3.13 46.9 2000 13.33 27.86 209 653.34
3.06 50.5 2100 0 0 0 700 3.0:1 54.1
______________________________________
Ground speeds can be calculated, and again using a wheel diameter
of 26 inches on the vehicle, at 700 engine rpm, the speed would be
approximately 3.6 mph, and at 2000 rpm, the speed would again be at
approximately 50 mph.
Obtaining a higher output rpm at a lower engine rpm can be
accomodated easily, by changing the ratios as desired. Again, in
this form of the invention the ratio control gear arrangement can
be replaced with variable pulley and belt control to eliminate the
electric motor if desired.
Additionally, the continuously variable transmission can be used
for a single-ended output shaft, that then could be used for
driving either a front or rear differential, or this type of
transmission could be used without torque proportioning, and thus
could be suitable for a wide variety of vehicles including all
terrain vehicles, motorcycles and the like.
FIG. 12 illustrates a first form of the single output continuously
variable transmission, and includes an outer housing 325, which has
an input shaft 326 leading from a power source that drives a spur
gear 327 in a normal manner. This is mounted in a suitable bearing
326A in the front wall of the case 325, and the spur gear 327 in
turn drives a second spur gear 32b that is rotatably mounted on a
shaft 329 that extends all the way through the case and out the
rear wall shown at 330. The spur gear 328 in turn is drivably
connected to a sun gear 331 that is rotatably mounted with gear 328
on the shaft 329, and the sun gear 331 drives multiple planet gears
332 that are rotatably mounted onto planet gear shaft 333. The
gears 332 drivably engage an internal gear shown at 334A of an
outer gear housing for the gear clusters, which housing is shown at
334 and provides a housing for the gear clusters that can be
controlled as to rotation for varying the output ratio between the
input shaft and the output shaft. The gear housing 334 is a ratio
control gear housing, or section, and has an outer large bevel gear
335 around the periphery thereof. Additionally, the planet shafts
333 are mounted fixedly in a planet shaft carrier 336 that
comprises a type of spider. The carrier or spider 336 is rotatably
mounted on the shaft 329 on suitable bearings or bushings. The
planet shafts extend parallel to the output shaft 329, and at the
rear end thereof, that is, the end opposite from the planet gears
332, there are second output planet gears 340 rotatably mounted on
the shafts 333. The output planet gears 340 drivably engage an
internal gear indicated at 341A of a gear housing 341 that
comprises a portion of the ratio control housing, and this housing
341 is rotatably mounted on the shaft 329, through a hub 342.
Additionally, the planet gears 340 drivably engage a sun gear or
central gear 344 that is keyed to or otherwise drivably mounted on
the shaft 329. Shaft 329 then extends outwardly from the case
through the rear wall 330 as previously mentioned. Of course, the
various shafts have suitable taper roller bearings on them,
generally.
The gear housing 341 has an outer bevel gear 345, fixedly mounted
thereon, and facing the gear 335. The gears 335 and 345 are spaced
apart so that a ratio control pinion 350 can engage both of these
gears, and the pinion is mounted onto a ratio control shaft 351
that, as can be seen in FIG. 13, for example, is suitably supported
in cross members 352 of the gear housing 325, and has a worm gear
355 drivably mounted thereon as well. The worm gear is spaced
axially along the shaft 351 from the pinion 350.
Suitable bearings shown at 358 can be used for mounting the shaft
351 in the cross members 352. The worm gear 355 is controlled by a
worm 360 that is drivably mounted onto a shaft 361 that comprises
the output shaft of a ratio control motor 362.
In this form of the invention, the drive ratios can be varied by
controlling and driving the motor 362, to turn the pinion 350 and
permit the outer ratio control gear casings or housings 334 and 341
to rotate and thereby control the output ratio between the input
shaft 326 and the output shaft 339.
Using the same size sun gear and planet gears, as well as the same
size spur gears 327 and 328, a one-to-one ratio will be achieved if
the outer housings 334 and 341 are held from rotation. To bring the
output shaft back to zero rpm when the engine is idling, would
require a slower speed of the pinion 350 than that of a pinion 392
shown in FIG. 15, for instance, because the two gear housings 334
and 341, which comprise the ratio control gear housings, would be
rotating in opposite directions. Thus the ratio can be changed more
readily with less speed of the control motor 362. Varying the speed
of control motor 362 in response to the engine speed, which would
be the speed of rotation of shaft 326, can provide an infinite gear
ratio.
FIG. 14 shows an alternative arrangement, wherein the planetary
shafts shown at 333A (the input spur gears and planet gears are
identically numbered with the form shown in FIG. 12) are carried in
a second planet shaft carrier 369, as well as carrier 336. The
carrier 369 and its hub 370 are fixedly mounted to the output shaft
329. Gear housing 341 that has a hub 342 that is rotatably mounted
on the hub 370 of the planet shaft carrier 369.
The planet gears 340A are merely engaged with the internal gear
341A of the gear housing 341, and do not engage any sun gear. Other
than that, the arrangement is identical including the use of the
control motor, and a ratio control pinion 350.
In the embodiment shown in FIG. 14, the same arrangement of the
gears is as shown in FIG. 13, and has the same size sun gears and
planet gears, the resistance to rotation is provided by the pinion
350, and the antireverse characteristics of worm gear drives, so
that when the control motor is not running, the outer gear rings
and gear housings will be held.
If desired, the gear housing 341 could be attached to the case, and
disengaged from the pinion 350, so there would not be any gear
drive there. The arrangement shown in FIG. 14 gives an alternative
or different output ratio from the form shown in FIGS. 12 and 13.
With a sun gear to annular gears (334A, 341A) ratio of
three-to-one, the output shaft 329 to input shaft 326 ratio is
three-to-one, as well. A one-to-one ratio is obtained with the FIG.
12 form.
In FIG. 15, a simpler version of a continuously variable ratio
transmission made according to the present invention is shown. This
device uses the same type of planetary gear arrangement, as shown
in FIG. 13, but has an input shaft 380 that drives a spur gear 381
on the interior of a gear case 382. The spur gear 381 drives a
second gear 383 that is rotatably mounted on an output shaft 384.
Gear 383 has a sun gear 385 drivably associated therewith for
rotation with the gear 383, relative to the output shaft 384, and
the sun gear 385 in turn drives a plurality of planet gears
386.
The planet gears 386 are rotatably mounted on planet shafts 387
that are fixedly mounted in a planet shaft spider or hub 388 that
in turn is drivably mounted on the output shaft 384. The planet
gears 386 also drivably engage sun gear 385. The planet gears 386
also drivably engage an internal gear 390A of ratio control gear
housing 390 that has an outer bevel gear 391 thereon. Control for
continuously varying the output ratio is achieved with a pinion 392
drivably mounted onto a ratio control shaft 393 that is rotatably
mounted in suitable bearings on cross members in the case 382. The
shaft 393 is arranged as shown in FIG. 13, and has a worm gear 394
drivably mounted on the shaft 393. A worm 402 is drivably mounted
onto an output shaft 403 of a control motor 404 that is the same
type of motor as previously described.
By varying the speed of the control motor, the rotation of the
ratio control gear housing 390 that controls the cluster gears for
the planetary action through the ratio control section 379 is all
that is necessary for controlling the output ratio between the
input and output shafts. This version shown in FIG. 15 is
simplified by reducing the number of gears, and provides for a
compact continuously variable transmission that would find adaption
in small vechicles such as garden tractors, all terrain vehicles,
or even motorcycles. In this instance, however, in order to obtain
zero output speed of the output shaft 384 when the input shaft 380
was at idling engine speed, the shaft 403 would have to rotate
faster than that shown in FIG. 12.
In this form of the invention also, the output ratio is
three-to-one if the sun gear to annular gear (390A) ratio is
three-to-one. The forms of the invention in FIGS. 14 and 15 are
especially useful in motorcycle application and provide infinitly
variable ratio transmission as well as a desired final drive ratio
in one small package.
All forms of the invention provide an easily controlled
continuously variable ratio transmission that can be adapted to a
wide range of applications for motorcycles, three-wheeled vehicles
and four-wheel drives, and with or without the torque proportioning
features.
Although the present invention has been described with reference to
preferred embodiments, workers skilled in the art will recognize
that changes may be made in form and detail without departing from
the spirit and scope of the invention.
While deviation from the wording of descriptions and the
presentation and proportions shown in the initial informal drawings
will occur as the invention is designed for specific applications,
the drawings and descriptions herein are held to encompass the same
and to be by way of explanation rather than limitation. Obviously,
innumerable departures are possible, such as: dimensions of axles
and drive shafts, shaft center distance, diametral pitch and pitch
diameter of gears, helix angle of worms and worm gears, design of
the outer case and assembly features; spacing, shimming, and
friction reducing components; and type and number of bearings,
materials, and lubrication mediums and methods. For instance, such
specifics as the use of different worm and worm gear helix angles
for the differentiated arrangement, with intention of enhancing
differentiation under some circumstances while not interfering with
retainment of torque, is an engineering design decision encompased
in the claimed inventive concepts depicted and described.
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