Golden Products and Services LLC.
Golden Products and Services LLC.
Continuous Variable Transmission (CVT) Special Patent
The principle goal of the transmission outlined in US patent #5,603,240 (2/18/97) is to provide a
(1.) Cam-Driven Transmission that is a mechanical transmission that is continuously variable from
Forward to Reverse
(2.) Energy Management System that smoothly converts kinetic energy to and from a potential energy
device, such as a fly wheel.
As discussed in the Technical Field of Invention including:
i.) Transmission capable of receiving power into its input in the form of rotational torque
and velocity, and exporting power from its output in the form of rotational torque and velocity
capable of being different then received.
ii.) Transmissions capable o continuously varying the exported rotational velocity between a
maximum value in a clockwise direction.
iii.) Mechanical transmission that converts rotary motion into oscillatory linear motion and
then selectively convert such motion back into rotary motion.
iv.) CVT having low vibration. The technical field of the present invention does not encompass
CVT using belts and pulleys, v-belts, or hydraulic pumps as that being used in current\present
Given that 80-90% of the capacity of most internal combustion engines (ICE’s) is for the purpose of
acceleration only. It is a wise use of the transmission’s energy management capabilities would
allow for the design of vehicles containing much smaller ICE’s, yet provide for equivalent, if not
superior, acceleration for most driving modes. This CVT System is very flexible, although the base
a four cam design, it can be built as a two, three, or six cam design. The four cam design
optimizes the opposing force loads to mitigate vibrations to balance the design. The other
operating designs can help use different rpm values resulting in an increased transmission speed
and physically smaller unit delivering different power levels.
The Challenges for this CVT System include:
(1.) Vehicle Integration current and future.
(2.) Combination of Controllers to work with this CVT. (3.) Manufacturing Tolerances and Costs.
(4.) Few situations like Continuous 20 miles Distance all up hill ( There may be a slowing down of
(5.) Discovery of full potential uses and configurations changes for building various models for
this CVT Optimization (i.e, one example: Utilizing usage of Electrorheological or
Magnetorheological Technology and another example: Using this CVT as an Energy Management System
By fly wheel it does not mean an ordinary fly wheel, but a light weight device designed to store a
tremendous amount of potential energy. Additionally, the transmission has potential applications
in hybrid vehicles, and even in all electric vehicles. The main claims of the patent refer to the
energy management capabilities since the CVT capabilities, including going from forward continuous
and into reverse continuous, combining the linear portions of multiple cams, and even balancing the motions
of members such as cam followers with opposition motions of similar members have been used in
The first patent brought forward for comparison was for a windmill comparison. A CVT is desirable
in a windmill application because it can be controlled in such as way that the output shaft runs at
a constant speed, thereby modulating the used to turn an armature through a magnetic field. It
used a cam system with similar characteristics to provide CVT capabilities.
The second patent brought forward for comparison was from a 1945 French patent by an inventor named
Schultz. That patent seemed to be directed towards the use of a similar CVT for the purpose of
moving large, heavy vehicles, such as those used for military applications (ie – tank). That design
relied on a one way clutch at the output shaft as a means of combining the contributions of each
cam while providing a release mechanism for any slight mismatches in velocity between cams. As a
result of the one-way clutch, it had no capability of sending energy back through the transmission
through a potential energy storage device.
In order to provide that capability, the use of “caliper-like” devices are used in the current
transmission to allow for energy to go both ways. Furthermore, it was deemed advantageous to have
the transmission continuously engaged. Hence, the cams were designed so that there would be a time
of overlap, where two cams are simultaneously engaged. Although there have been CVT designs that
have relied on cam profiles that are not linear in Theta (turning of the cam), any non-linearity
during the time of simultaneous engagement of the cams will cause the cams to pull against each
other in a way that is undesirable and inefficient. Each cam has a profile with a portion that is
linear in Theta covers 90% plus enough angle to provide sufficient overlap. When ICE drives the
transmission the high RPM is geared down at a constant ratio (maybe future technology will allow
that step to be eliminated) to a lower RPM used to drive an input shaft. The cams convert the
rotation of the input shaft into displacements. Those displacements are put through the physical
equivalent of a dot product in order to scale the displacements to any value between -1 and 1. The
“caliper-like” devices are designed to reconstruct the scaled output by engaging the flanges
connected to the rack-and-pinion
only during the portion where the corresponding input cam is linear in Theta. When it is desired
for the vehicle to slow down, the kinetic energy is converted to potential energy instead of
dissipated. A change in the gear ratio alone can send the energy back through the transmission to
an overriding potential energy storage device. The same energy used to slow the vehicle down can
be used to accelerate it again. While a vehicle is warming up, energy can be placed into the
potential energy storage device to enable initial acceleration.
There are several advantages to this CVT:
1.) Reduction in engine and transmission sizes.
2.) Better fuel economy.
3.) Lower fuel consumption resulting in reduced emissions for pollution control.
4.) Higher efficiency in horse power per engine volume.
5.) Less vehicle weight.
6.) Direct regenerative braking.
7.) Multiple configurations for design. (i.e. four electric motors, one/tire eliminates
differentials resulting in better handling characteristics)
8.) Flexibility in design for all types of engines and vehicle weight classes.
The Best applications of this Type of a CVT is for :
- All types of I.C.E’s (High Mass Vehicles including: Tractors/ Military Trucks/Civilian
Trucks,Heavy/Medium Vehicles, Three-Wheeler Taxi’s (Rickshaw, Alibaba).
- Hybrid Vehicles.
- Electric Vehicles.
Note that the patent does not mention several of the innovative ways to use the transmission,
including having one at each wheel in conjunction with four electric motors. The energy recovery
and management capabilities of the transmission are its key selling points. They enable the use of
a smaller engine that will produce results that are equivalent to that of a larger engine for nearly
all driving modes. Most of the horsepower required for most automobiles is for acceleration. In
city driving most of the energy used for acceleration will be captured while stopping. The
transmission can also handle large torque situations, such as required for tractors and large
trucks. Regenerative braking on buses in Europe using generators have been around since before
this patent, but even in those situations, the regeneration has not been at optimal torque
conditions. Also, the transmission enables the smooth release of stored energy. There is great
confidence that the transmission will work quite efficiently. A Proof of Concept should be pursued to eliminate the main concerns having
more to do with the costs of achieving certain manufacturing tolerances and the possibility that
other economic manufacturing factors could prevent its adoption. An in depth study for feasibility
and marketability in the World Market should be introduced. Hopefully the advantages of this design
for the world economies will out weight any issues and obstacles encountered in the effort to bring
this technology to mass production for the world markets.