Asymmetric planetary gear variable speed transmission

An infinitely variable forward speed mechanical transmission uses asymmetric helical/spur gear trains mounted to rotate within a rotor assembly to reduce the torque output within the rotor assembly through inefficiency of the asymmetric gear trains. The rotor assembly includes integrated input and output hubs having adjacent radially flush outer control surfaces, with the output hub in mesh with the asymmetric helical/spur gear trains in mesh with an output shaft. A transmission speed control device connected to a control gear connected to a control tang of a wrap spring positioned about the control surfaces of the input and output hubs provides infinitely variable control of the relative rotation of the two hubs to selectively control the torque output of the transmission. A planetary gear set in constant mesh with the transmission input through the input hub provides a full-time low-gear ratio, and an attached dual sprague clutch assembly determines the driving output train of the transmission between the planetary gear set and the output shaft.

FIELD OF THE INVENTION 
The present invention relates to infinitely variable speed power 
transmissions. 
BACKGROUND OF THE INVENTION 
Many mechanical power transmissions use hydraulics, planetary gear 
assemblies and/or chain belt combinations to accomplish infinitely 
variable speed power transmission. Such transmissions rely on traction for 
transmitting power. However, in automotive applications, such 
transmissions are too heavy and too large in size to practically transmit 
torque in a range of for example 250-300 ft./lbs. Presently used four 
speed electronically controlled transmissions have a multitude of 
components and are very complex, particularly in performing forward gear 
selection and shifting. 
SUMMARY OF THE INVENTION 
The present invention provides an improved mechanical geared infinitely 
variable speed transmission having a torque range within the expected 
performance of an automotive transmission, wherein forward speed change is 
affected by asymmetric gear pairs within a transmission rotor controlled 
by a small power output manipulator. Transmission speed changes are made 
with full time gear engagement. 
The transmission of the present invention includes a modified planetary 
gear assembly within a rotor having several stages of asymmetric gear 
pairs such as two or more which serve to reduce the torque output within 
the rotor resulting in a torque reduction, through the inefficiency of the 
gear pairs, of for example at least 67%. Torque is reduced only within the 
rotor. 
The transmission of the present invention is based upon utilizing gear 
inefficiency specifically designed to the highest possible level. The 
maximum inefficiency is one directional only, and highly efficient in the 
opposite direction. This is achieved by pairing spur gears with helical 
gears of the same pitch mounted on an angle equal to the helix angle 
within a torque reducing rotor mounted axially about the transmission 
drive line. Torque reduction is equal to the cosine of the included angle 
of meshing intersection of the helical gears with the spur gears. What is 
considered inefficiency in a conventional gearbox becomes rotational force 
on the rotor in this invention. Within the rotor this inefficiency, 
through several stages of asymmetric gear pairs, diminishes the torque 
input to a small fraction of the original input. The total value of torque 
is not diminished, but the larger portion of the torque input turns the 
rotor. When a lower speed ratio is selected, the torque is increased. The 
preferred torque reduction within the rotor is approximately 70%. Since 
the torque reduction is one directional only, and a wrap spring about the 
rotor controls the remaining torque, transmission speed change can be 
effected easily with a small mechanical force. The gears are arranged 
inside the rotor so that a slower relative rotation of the final internal 
gear results in slower rotor output shaft rotation. In effect, the rotor 
output speed slips relative to the rotor input speed. 
A transmission speed manipulator in accordance with the invention can 
maintain an equal or 1:1 ratio with the rotor assembly rotating in sync 
with the transmission input. Any desired speed ratio may be maintained, 
but not lower than the ratio of a constant mesh full time low speed 
planetary gear set positioned about the output shaft following the output 
of the rotor. Customarily in automotive applications the low speed gearing 
provided by the constant mesh planetary gear is in the range of 3.3:1. 
When the rotor output speed slips below the planetary gear set's output 
speed, the planetary gear takes over and the rotor's internal mechanism is 
bypassed. Torque is directly transmitted through the rotor housing to the 
planetary gearing to output. 
Since automobile transmissions customarily operate in a 1:1 or overdrive 
mode most of the time, and low gear is bypassing the device, the torque 
reduction geartrain of the rotor is therefore actually operating only a 
small fraction of the time. The asymmetric helical/spur gear sets are used 
to reduce torque within the rotor because they do not generate heat and do 
not operate at high speeds. Alternatively, this type of torque reduction 
can be accomplished through the use of worm gears, high ratio gear sets, 
or friction clutches. 
The speed manipulator of the invention, which controls engagement of the 
torque reducing gear trains of the rotor, can be mechanical, hydraulic, 
electrical, or any device which can maintain a steady equal or lower speed 
than the input speed. The required force needed to effect speed change 
speed is very small, for example, less (but not more than) approximately 
50 lb./in. A preferred device is a mechanical traction device which has 
infinitely adjustable mechanical traction and which is also of simple 
construction small size. Speed change can be effected in stationary or in 
rotational mode. Reverse gear and other transmission components are not 
shown in connection with the invention but are fully compatible with the 
invention. 
In accordance with one aspect of the invention, a variable forward speed 
mechanical transmission includes a transmission output torque reducing 
rotor assembly adapted to rotate about an axial center line of a drive 
train which includes an input rotor connected at one end to a power output 
and having an outer radial control surface at an opposite end, a control 
hub having an outer radial control surface adjacent to and radially flush 
with the outer radial control surface of the input rotor and internally 
meshed with a symmetrical helical/spur gear train having a torque reducing 
effect when turning through the inefficiency of angular helical/spur gear 
interfaces terminating at meshed connection with a spur gear on an output 
shaft, and a wrap spring about the adjacent flush outer radial control 
surfaces of the input rotor and outer hub to control relative rotation of 
the input rotor to the control hub. 
In accordance with another aspect of the invention, a speed control device 
provides infinitely variable adjustment of the relative rotation of the 
input rotor to the control hub by interconnection with a control tang of a 
wrap spring about control surfaces of the torque reducing rotor, wherein 
the speed control manipulator includes a speed control gear in mesh with a 
control gear of the transmission rotor and mounted axially upon a cone 
rotated by frictional contact with an inner radial surface of the cone 
with an elliptical shaft mounted through the cone and supported within a 
yoke adjustable in a vertical plane to change the point of rotational 
contact between the inner surface of the cone and the shaft to thereby 
change the rate of rotation of the speed control gear to change the force 
exerted by the speed control gear upon the control tang of the wrap spring 
.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
With reference to FIG. 1, there is shown from the side a transmission 
assembly, indicated generally at 10, which includes an internally geared 
rotor assembly 12, planetary gear set 14, and a dual sprague clutch 
assembly housing 16, each positioned and mounted to rotate radially about 
a common axis. As is known in the art, the transmission 10 may be mounted 
to rotate radially about a core shaft 11 which may be, for example, a 
hydraulic pump shaft. Alternatively, the transmission 10 may be mounted 
and journalled to rotate against external bearings (not shown) as is also 
known in the art. Also, the transmission assembly 10 can be easily adapted 
to fit within common transmission housings of, for example, automobiles 
without substantial modification and redesigning of the power drive train. 
A shaft portion 20 of a power input rotor 18 protrudes from rotor assembly 
12 and is provided with primary spline teeth 19 for engagement with an 
engine output gear (not shown). A speed control manipulator, represented 
schematically by box 22, is positioned for engagement with a control gear 
24 and a reference gear 26 at respective opposing lateral ends of rotor 
assembly 12. Through a torque reducing gear arrangement within rotor 
assembly 12, controlled by speed control manipulator 22 and transmitted 
through the dual sprague clutch assembly 16 to an output gear 90, the 
forward driving torque output of the transmission 10 can be infinitely 
adjusted as described in detail below. 
FIG. 2 illustrates in partial cutaway a side view of rotor assembly 12, 
planetary gear set 14, and dual sprague clutch assembly 16 as shown in 
FIG. 1. The speed control manipulator 22 is not shown in FIG. 2. Beginning 
at the right side of FIG. 2, input rotor 18 enters into transmission 
housing 30 through bearing 32. Input rotor 18 includes secondary spline 
teeth 29 inside transmission housing 30 for rotational driving engagement 
of reference gear 26. Input rotor 18 continues linearly beyond reference 
gear 26 to extend radially, terminating with a radially peripheral speed 
control surface 38 at a radially outermost portion. 
FIG. 3 illustrates input rotor 18 in isolation in profile and partially 
cutaway, showing primary spline teeth 19, secondary spline teeth 29, speed 
control surface 38, a horizontal gear mounting cutout 21, diagonal gear 
mounting cutout 23 shown in phantom, and a needle bearing surface 31 for 
control gear 24. 
FIG. 4 illustrates the components of the torque transmission path of input 
rotor 18, planetary gear set 14 and dual sprague clutch assembly 16 in 
isolation. A forwardmost end 33 of input rotor 18 is attached, for example 
by screws 35, to an input rotor extension 70. As described in greater 
detail below, input rotor extension 70 is in mesh with planetary gear set 
14 the output of which is attached to one of the clutches of the dual 
sprague clutch assembly 16 to drive the final output gear 90. 
As shown in FIG. 2, in the rotor assembly 12, the input rotor 18 is 
integrated with a control hub 58. The torque transmission path from 
control hub 58 is described with reference to FIGS. 2, 5, 6 and 7. The 
control hub 58 is essentially a ring gear which has an outer peripheral 
control surface 60 (adjacent to and radially flush with control surface 18 
of input rotor 38) and internal gear teeth 56. 
With reference to FIGS. 5 and 6, a main sun gear 40 at an end of an output 
shaft 42 is in mesh with one end of a helical/spur gear train. The torque 
reducing asymmetric helical/spur gear train is now described beginning at 
main sun gear 40. Main sun gear 40 is in constant meshed engagement with 
an asymmetric pair of helical planetary gears 44a and 44b positioned, for 
example, at radially opposite points of main sun gear 40 and mounted at an 
angle equal to the helix angle to mesh with main sun gear 40. As shown in 
FIG. 7, the angle at which helical planetary gears 44a and 44b are mounted 
relative to main sun gear 40 can be, for example, 50.degree., but can also 
be mounted at any angle within a range of for example approximately 
40.degree. to approximately 90.degree.. The final torque reduction ratio 
of the asymmetric helical/spur gear train is equal to the cosine of the 
mounting angle of the helical planetary gears 44a and 44b relative to the 
main sun gear 40. The greater the angle of meshing intersection of helical 
planetary gears 44a and 44b with main sun gear, the greater the torque 
transmitting inefficiency of the transmission, thereby increasing the 
torque reducing capacity of the transmission. 
As shown in FIG. 6, each asymmetric helical planetary gear, 44a and 44b, is 
mounted at one distal end of a respective diagonally mounted shaft, 46a 
and 46b, each of which has a respective spur gear, 48a and 48b, mounted at 
an opposite distal end thereof. The only difference between shaft 46a and 
shaft 46b and the respective attached gears is the radial position 
relative to main sun gear 40 and the symmetrically opposite diagonal angle 
of departure away from main sun gear 40 to the axial center line of output 
shaft 42. Spur gears 48a and 48b are in respective constant meshed 
engagement with horizontally mounted asymmetric helical gears 50a and 50b 
which are mounted on respective horizontal shafts 52a and 52b with spur 
gears 54a and 54b. As shown in FIG. 2, horizontal shafts 52a and 52b are 
rotationally supported at distal ends within reference gear 26 and the 
radially extending portion of input rotor 18. Cutout portion 21 of input 
rotor 18 accommodates horizontally mounted asymmetric helical gears 50a 
and 50b. Cutout portion 23 of input rotor 18 accommodates diagonally 
mounted helical planetary gears 44a and 44b. 
In FIG. 2 and FIG. 5, there is shown the meshed engagement of spur gear 54a 
with control hub ring gear 56 formed in the internal circumference of 
control hub 58. As previously noted, control hub 58 has a slightly 
recessed outer radial surface 60 which is radially flush with control 
surface 38 of input rotor 18 to form a flush uniform input/output control 
surface (surfaces 38 and 60 combined) over the entire circumference of 
which a speed control wrap spring 62 is positioned. Control gear 24 is 
positioned to rotate about the radial surface area 31 of forward end 33 of 
input rotor 18 as shown in FIG. 2. Surface area 31 of input rotor 18 may 
include periodic pockets for receiving needle bearings upon which control 
gear 24 rotates. 
Wrapped about the adjacent radially flush control surfaces 38 and 60 is a 
wrap spring 62 which interlocks in rotation input rotor 18 with control 
hub 58 when control gear 24 rotates at the same speed as input rotor 18 
and reference gear 26 (in mesh with gear teeth 29 of shaft portion 19 of 
input rotor 18). When input rotor 18 and control hub 58 are locked in 
synchronous rotation under the radially constrictive force of wrap spring 
62, the torque output ratio of the transmission is 1:1 with the entire 
rotor 12 spinning at the velocity of the input rotor 18. As the radially 
constrictive force of wrap spring 62 is reduced by counter-rotating 
pressure exerted on control tang 68 of wrap spring 62 (as a result of 
relative slower rotation of control gear 24), input rotor 18 and control 
hub 58 are no longer locked in synchronous rotation, such that control hub 
58 is allowed to slip relative to the input rotor 18, thereby inducing 
rotation of the asymmetrical helical/spur gear train by the following 
sequence: control hub ring gear 56 rotating (slipping relative to the rate 
of rotation of input rotor 18) to rotate spur gears 54a and 54b which 
rotate respective shafts 52a and 52b which rotate horizontally mounted 
helical gears 50a and 50b which induce rotation of diagonally mounted spur 
gears 48a and 48b which rotate respective shafts 46a and 46b which rotate 
helical planetary gears 44a and 44b which induce rotation of main sun gear 
40 and output shaft 42. The torque thus transmitted from input to output 
is substantially reduced through the frictional inefficiency of the 
asymmetric helical/spur gear train leading to output shaft 42. The input 
torque is reduced to an extent that the speed control manipulator 22 can 
easily control the rotational speed of control gear 24 and thus the 
pressure upon the control tang 68 of wrap spring 62 to release the wrap 
spring from the control surfaces to allow slipping of control hub 58. Of 
course, to give additional torque reducing capacity to the rotor 12, 
additional sets of the described helical/spur gears could be incorporated 
into the rotor. 
As shown in FIGS. 8A and 8B, control tang 68 fits within a pocket 69 in the 
internal periphery of control gear 24 so that as control gear 24 is slowed 
in the direction indicated the resulting force upon the control tang 68 in 
the same direction unwraps or reduces the inward radially constrictive 
force of wrap spring 62 upon the control surfaces. Thus, torque speed 
change is effected only when a counter-rotational force is exerted upon 
control tang 68 of wrap spring 62 by control gear 24. This force is 
exerted upon control tang 68 by control gear 24 at any time control gear 
24 is rotating at a speed less than reference gear 26, i.e., the speed of 
the transmission input. The control manipulator 22 (in meshed engagement 
with control gear 24 as described below) needs to exert force upon the 
control gear 24 sufficient only to slow the rotational speed of control 
gear 24 to move control tang 68 against the radially inward bias of wrap 
spring 62. 
Referring again to FIGS. 2 and 4, input rotor 18 is connected to planetary 
gear set 14 by attachment to input rotor extension 70. The full time 
engagement of the input rotor 18 to the planetary gear set 14 provides an 
absolute minimum gear ratio for high torque/low speed operation as is well 
known in the art. Spur gear teeth 74 are provided on a distal end 72 of 
input rotor extension 70 to serve as a sun gear for planetary gears 76 of 
planetary gear set 14. Ring gear teeth 78 in the internal circumference of 
transmission housing 30 are in mesh with planetary gears 76 supported by 
planetary gear shafts 80 supported by and journalled to rotate within a 
planetary gear carrier 82 at one end and planetary gear housing 85 (which 
also serves as a sprague clutch support) at the other end. 
Planetary gear set 14 produces a driving ratio equivalent to the first gear 
or low gear in a conventional transmission, with a gear ratio of, for 
example, between 3:1 to 4:1. The main sun gear 40 thus has a variable 
ratio of, for example, between 1:1 and 5:1. The transmission of this 
embodiment thus has an absolute minimum ratio of that of the planetary 
gear set 14 below which the torque reduction action of the rotor 12 cannot 
drop. Otherwise it will be appreciated that the transmission may consist 
solely of the described rotor 12 and the accompanying speed control 
manipulator 22 in any particular application. 
To determine whether the final output of the transmission will be driven by 
the input rotor/planetary gear arrangement of FIG. 4, or the control 
hub/torque reducing gear train of FIG. 5, both arrangements are connected 
to the dual sprague clutch assembly 16 as shown in FIGS. 2, 4 and 5. As 
shown in FIG. 4, a sprague 86 is attached to the outer radial surface of 
planetary gear housing 85 and is in contact with the internal radial 
surface of clutch case 84. The final output gear 90 of the transmission is 
attached to clutch case 84. As shown in FIG. 5, spur gear teeth 43 at a 
distal end of output shaft 42 are engaged with a second sprague supporting 
member 88 with second sprague 87 attached to an outer radial surface 
thereof. The second sprague 87 is also in contact with the internal radial 
surface of clutch case 84. Thus if the second sprague supporting member 88 
is spinning faster than planetary gear housing 85, then the contact of 
second sprague 87 against clutch case 84 becomes the rotational driving 
force of clutch case 84 and the final output gear 90 attached thereto. 
Conversely, if the planetary gear housing 85 is spinning faster than the 
second sprague supporting member, then sprague 86 (as directly driven by 
input rotor 18) provides the rotational driving force of clutch case 84 
and the final output gear 90 attached thereto. Both clutches are 
free-running in the same radial direction. Whichever clutch rotates 
fastest drives the final output gear 90 attached to clutch case 84. In 
this manner, the transmission can maintain a minimum speed ratio of, for 
example, approximately 3.5:1 at any time the rotor output speed slips 
below the minimum planetary gear set speed ratio. For example, in the 
state of low speed/high torque, torque is transmitted through input rotor 
18, input rotor extension 70, to planetary gears 76, to planetary gear 
clutch 86, to clutch case 84, to output gear 90. 
FIG. 9 again shows transmission assembly 10 (including rotor 12, planetary 
gear set 14, and dual sprague clutch housing 16) with rotor 12 in meshed 
engagement with a mechanical speed control manipulator indicated generally 
at 22. As shown schematically, the speed control manipulator 22 can be 
mounted directly on top of transmission 10 in any configuration which 
allows for constant mesh of a speed manipulator control gear with rotor 
control gear 24 and reference gear 26 of rotor 12 as described below. 
Although the speed control manipulator 22 described herein is mechanical, 
it is to be appreciated that hydraulic, electric, electromechanical, 
electronically controlled and other types of manipulators including 
hybrids thereof capable of the described operation can be used in 
connection with the transmission of this invention. 
FIG. 10 illustrates in isolation a portion of a mechanical speed control 
manipulator 22 which includes a speed control gear housing 94 which houses 
a cone 96 upon which a speed control gear 98 (both shown in cross-section) 
is coaxially mounted at, for example, the angle shown, with a top side 
edge of the cone 96 horizontal, to position the teeth of speed control 
gear 98 for meshed engagement with control gear 24 of rotor 12 as shown in 
FIG. 9. Cone 96 is supported to axially rotate about bearings 93 and 95 
mounted within the speed control gear housing 94. The internal surface of 
cone 96 is precisely finished to, for example, sixteen thousandths of one 
inch. Cone 96 is rotated about one point of its internal diameter surface 
by frictional contact with a slightly crowned elliptical spool 100 mounted 
upon a spool shaft 102 which is supported at each respective distal end by 
bearings 103 and 104. Bearings 103 and 104 are supported in a yoke 106 
which fits over and is attached to the top of gear housing 94 by rods 109 
and 111 surrounded by springs 107 and 108 respectively. Movement of a 
manipulator lever 110, connected to yoke 106 by a cam 99 at a top end of 
rod 111, changes the linear attitude of the yoke 106 relative to gear 
housing 94, to change the angular attitude of spool shaft 102 in the 
vertical plane, and consequently the point of contact between spool 100 
and the interior surface of cone 96 to thereby change the rotational speed 
(by changing the radius of rotation) of speed control gear 98 and 
consequently the allowed rotational speed of control gear 24 (in mesh with 
speed control gear 98), and consequently the pressure exerted upon the 
control tang 68 of wrap spring 62 to control the described torque 
reduction/slipping action of rotor 12. 
The large end A of cone 96 has a diameter of, for example, 4.0 times the 
mean shaft diameter of spool 100 and, the small end B of cone 96 has a 
diameter of, for example, 1.2 times the mean shaft diameter of spool 100 
as shown in FIGS. 11 and 12 respectively to define the range of speed 
variation of speed control gear 98. 
FIG. 13 illustrates the manner in which the manipulator lever 110 is 
connected to control gear housing 94 by shaft 111 about which spring 108 
is positioned. One end of shaft 111 terminates off center within a cam 99 
attached to manipulator lever 110 which is rotated upon movement of lever 
110 to draw control gear housing 94 upward toward yoke 106 against the 
force of spring 108, to thereby change the attitude of spool shaft 102 and 
the point of contact of spool 100 upon cone 96. 
As shown in FIG. 9, a reference gear driving input to the speed control 
manipulator 22, to rotationally drive spool shaft 102 and speed control 
gear 98 within the control gear housing 94 at the same rate as the power 
input to the transmission, is provided by a drive linkage beginning with 
reference gear 26 of rotor 12 in meshed engagement with a transfer gear 
112 attached to shaft 114 which terminates at an opposite end with a 
sprocket or pulley 116 in linked or belted rotational engagement with 
sprocket or pulley 118 by a chain or belt 119. The drive train ratio of 
sprocket 116 to sprocket 118 is, for example 1:1.2 to match the minimum 
diameter of small end B of cone 96. Sprocket 118 is at one end of a spool 
shaft drive line, indicated generally at 120, which includes universal 
joints 122 and 124 which provide vertical planar adjustable driving 
rotation of spool shaft 102 in accordance with any adjustment of the 
attitude of spool shaft 102 by yoke 106 as described above. By this 
arrangement there is provided a constant reference geared driving input to 
spool shaft 102 and speed control gear 98 at all possible points of 
adjustment of yoke 106. It is to be noted that the described adjustment of 
the speed control manipulator 22 by movement of lever 110 can be done 
irrespective of the state or speed of the transmission rotor 12 so that 
the output speed of the transmission can be adjusted or selected at any 
operational point between stationary and top speed. 
In another embodiment of the speed control manipulator 22 not shown by the 
drawings, an electric motor can be used to rotationally drive spool shaft 
102 to rotate cone 96 and speed control gear 98, with the input speed of 
the motor determined by input from an electronic speed sensor directed to 
the transmission input as is known in the art. The speed of the speed 
manipulator motor is then adjusted relative to the sensed transmission 
input speed to increase or decrease the torque output of the transmission. 
Although the invention has been shown and described with respect to one 
version of a preferred embodiment, equivalent alterations and modification 
of the components and methods of the invention may occur to those skilled 
in the art upon reading and understanding this specification. The present 
invention includes all such equivalent alterations and modifications, and 
is limited only by the scope of the following claims. 
STATEMENT OF INDUSTRIAL APPLICATION 
It will be appreciated that the invention may be used as a power 
transmission in a wide variety of power generation and output devices.