CA2458368A1 - Tatran - Google Patents

Abstract

A CONTINUOUSLY VARIABLE, OR AN AUTOMATIC
TRANSMISSION WITH 4, OR 6 SPEEDS, PLACED
TRANSVERSLY OVER THE FRONT, OR REAR AXLE OF
THE VEHICLE - HAS THE ABILITY TO REDUCE THE
ENGINE'S REVOLUTIONS FEEDING INTO THE SAID
TRANSMISSIONS AND TO COMPLETELY ELIMINATE
THE FINAL-DRIVE AND DIFFERENTIAL ASSEMBLIES
FROM THE SAID AXLE, WHILE PROVIDING ITS
DRIVIG WHEELS WITH DIFFERENT ROTATIONAL
SPEEDS REQUIRED TO NEGOTIATE TURNS.

Description

~~ I~ E~L~' ~ IeICo TATRAN
TRANSVERSE
AUTOMATIC TRANSMISSION
INTENDED FOR 4, or 6 SPEED
AUTOMATIC, or CVT TRANSMISSIONS
February 24, 2004 Nicholas lVt. Ottly 7 Aylesbury Rr.
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INTRODUCTION
Automotive history teaches us, that virtually all motor cars produced since their inception in the 19th century, transmit the engine's power to the wheels in the same sequence:
the power generated by the motor goes first to a torque converter, (or lately to a spool of a CVT) and then to the gearbox. From there, it travels to the "final drive", or differential, where a speed reduction, consisting of a pinion and crown gear takes place.
Only now will the driving wheels turn at the desired road speed.
Attain Technology advocates significant changes to the above sequence and in the re-distribution of power within the power train served by automatic transmissions and CVT's.
What Is "Tatran" - And How Dmes It Work?
The name Tatran is an abbreviation for a Transyerse A,utomatie Transmission', because the proposed device is located transversely in the chassis, connecting two wheels of the same axle. It can be used in FWD, RWD, as well as in AWD
configurations.
Tatran brings with it three sign cant innovations: 1. a change to the sequence in which the engine power is transmitted to the wheels, 2. "speed reduction at source"
and 3. the eliminations of the final drive - or differential housing - in all automatic transmissions.
The power from the engine goes first to a speed-reduction gear set, and then to an automatic transmission. from where it is directly applied. to the wheels.
Consequently, there is both a change in the seguence in which the power is applied - as well as a speed reduction at the source,.
Apart from the two above changes, whose main purpose is to save the transmissions from unnecessary strain and to extend its service life- the third objective is to completely eliminate the differential assembly. its gears, and the housing -with the final drive - while retaining all the functional features of a "differential", so essential in the safe operation of a modern vehicle.
Therefore. TATRAN is suited for all passenger, SUVss light trucks, or similar all-terrain- vehicles, using the current automatic transmissions as well as new CVT
gearboxes.

In addition to that, TATRAhI's innovations are emine~ntly suited for today's hi~h-nerformance autos on account of the ever-increasing horsepower and torque. -Their augmented rower and revolutions are first reduced in RPM's before they are applied to the transmission, and then split into two, evenly divided ener~y streams - left and right sides of the TATRAN transmission, thus greatly extending the life of the power train.
*****
CONTINUOUSLY VARIABLE TRANSMISSIONS - or CVT
At present, the popularity of the CVT is on the increase; some automobiles, or SUV's offer them as an option, such as GM's Saturn, Honda, Toyota and Audi, etc., while Nissan's SUV, the Murano, comes only with a CVT transmission. Since the CVT is relatively, new some details are included.
Essentially it consists of two spools, about 10 to 14, incl-~es apart; which are connected by a special belt, but held apart by supporting columns - as shown in Figure OI. The internal mechanisms of the shaft mounted pools can change their diameters simultaneously. While the diameter of one spool increases - the diameter of the opposite spool decreases, and vice versa. The driving spool is driven by the engine, while the driven spool connects to the final drive, the differential housing - and then the wheels.
In all the current CVT's there is only one belt and two ;stools.. Attain Technology Inc.
advocates changes to this set up - which is detailed below. Please see illustrations of CVT transmissions on Figure 01 and Figure 02. .

A. TATRAN & C'VT
GENERAL DESCRIPTION
In a FWD Vehicle the front of a longitudinally placedl engine terminates in a small flywheel, a fluid coupling and a supported worm-gear, vvhich drives a matching worm wheel above it at a ratio of around 1:4 The assembly at the flywheel also has a provision for a reverse gear The large worm-wheel is integral, or fastened to 2 two) driving spools of the CVT, supported by side beams which provide the driving cones and spools with stability and room to move sideways. It also allows them to keep the same distance from the driven spools above, connected by the driving chains. Located in the center of the same shaft, the engine driven worm-wheel turns at exactly the same speed as the driving spools.
Positioned ahead of the two (left & riQ;ht drivin spools are the two corresponding ~r~ven spools. Tosether with the belts and their cone-sliding mechanisms -they constitute the entire CVT Transmission.
Each driven spool leads first into a wheel hub with water-cooled (~tiona~ -inboard disc brakes - and then to an internal U joint - a half-shaft, and a wheel. The same assembly on the other side - c~nstitutes a complete Front iWheel give Train.
Since the driven spools are not in-line with the en~ine''s crankshaft - the TATRAN-CVT transmission cannot use the "lock-out" feature in which all the years and hydraulics are bypassed. FIowever, this is also one of tlhe great advantages of this new CVT!
The above TATRAN-CVT application can be easily duplicated in a Rear Wheel Drive vehicle, or in AWD 4x4 SUV.

FIGURE S

TATRAN - CVT - TOP VIEW
1. a longitudinally placed engine has an extension to its crankshaft that supports a worm-gear, that engages a suitable worm wheel. The ratio of the worm gear and wheel is about 4: I, but it may vary Behind the worm gear is a starting clutch, a provision for reverse rotation and a fluid coupling 2. the large worm wheel is on the same axis as the h~o driving spools are attached to it, one for the left. The other for the right wheel. They are solidly connected to the main shat and contain mechanisms that expand and contract their diameters 3. placed some 10 to 14 inches ahead but mounted separately are the left-and-right driven spools; these are then connected to the driving spools through the two chains, and supported by the sides of the transmission box. The driven spools meet in the center of the CVT but are allowed to rotate at different speeds from each other; while the spools are allowed to contract &. expand, their centers are firmly attached to their shafts in order transmit their rotation 4. the shafts of the left and right spools extend further out - first, they form bearings for the internally mounted disc brakes - and reaching out they form wheel hubs that support internal a joints of the axle's half shafts 5. since the axles - or the pair of driven wheels - has two belts each wheel can be driven at different velocities which will come into play when the vehicle negotiates a turn. - The computerized CVT control will have two modules: one for the left and one for the right wheel. - The inputs will come from the ABS
wheel-rev counter, vehicle speed, lateral C~-forces - and other factors -currently available in most vehicles 6. transmission-case, enclosing all Tatran-CVT components. Please note, that there is no differential casing, nor a 'final drive' - this is all that is needed.

TATRAN - CVT - SIDE VIEW
1. Engine - FWD, or AWD
2. crank-case of engine with: small fluid coupling, clutch, provision for reverse gear and "nose", to support the bearing of the worm-gear 3. worm-gear engaging worm-wheel (above) - with front bearing support 4. worm-wheel, reducing engine's RPM to about 30% to 25%
5. one of the two driving spools (left and right) 6. one of the two driven spools 7. one of the two 'driving belts"

8. transmission case 9. disc brake of the front wheel 10. front wheel SUMMARY OF BENEFITS REALIZED
THROUGH THE APPLICATION
OF TATRAN-CVT
With the Speed reduction At Source the CVT traalsmission rotates only at about 25% of the original engine speed - prolonging i:he life of the With the 'split' CVT function - torque applied equally to each wheel - and yet each wheel will be independent. The current maximum torque ratings for the belts - by various manufacturers in 2004 are about 250 to 300 lbs. Two belts - rather than one, will increase the torque rating substantially, if not doubling it ~ During turns, Tatran-CVT's will take care of the speed differences through an algorithm based on: 1 ) the position of the steering wheel - or the front wheels proper, 2) by vehicle speed, brake application, if any, 4) slippage, and so on. -These calculations are routinely executed today ~by ABS, stabilitr~ and traction controls - mostly with the help of brake application, rather than the 'limited slip' differentials.
THE RESULTS
The TATRAN-CVT transmission will also deliver increased life ex ep CtanCy and reliability While the original CVT carried the entire load with one sin lg a belt, the TATRAN - CVT transmission will run about 75% slower and will share the power load with two belts.
In the TATRAN-CVT application - the differential housing, its gears. etc. are completely eliminated, which in spite of a dual-type gearbox with two belts will result in a much lighter vehicle that is more economical to produce. The weight savings in a passenger - or SUV vehicle - could range from 7S to 125 lbs. and would senerate substantial savinES in the production.

B. TATRAN - WITI~ A 4 &, 6 SPEED
AUTOMATIC TRANSMISSION
GENERAL DESCRIPTION
The application potential of a TATRAN Transmission - v~rith a 4, or 6 speed gear-box is similar to the CVT's which is, almost universal. It can used in FWD, or RWD
vehicles and the engine, power can be transmitted to it by gears ~- or by chains, or a long shaft.
Engines can be placed longitudinally - or laterally, as per present practice. -For the sake of simplicity, a FWD installation using gears, or a chain, will be used to describe its functioning below. - Further explanations accompany the Figures.
The prime example introduced below uses a north-south positioned engine of a FWD
vehicle; placed behind the front axle - and slightly off center. The front of the crankcase with its flywheel, has a fluid coupling with a 2-speed reduction gear set and a provision for a reverse gear.
The functioning of the TATRAN' transmission with a Gearbox is as follow:
~ Outside of the crankcase is the main power transmission gear set (or chains), consisting of a small diameter pinion gear - and engaging ~ the large crown gear at 90°. The outside gears remain. in permanent contact and their ratio doesn't change, while the internal speed reduction set is used to switch during the gear selection. It is understood, that these two gear sets will have to "harmonized" together to achieve balanced results.
The large "crown gear" is flanked by two smaller diameters torque converters -and on the outside of these - by two set of gear boxes; if the transmission calls for 4 speeds, then each gear box will have only 2 gears; on the other hand if it has 6 -then 3 speeds will be needed ~ TATRAN uses the centrally located 2-speed gear set as a pre-selection device, so that the 2,m or 3 gears are multiplied - so they become 4, or 6 but going to the left and right sides of the vehicle. The computerized transmission module will simultaneously shift the gears in both the sides ~ TATRAN encloses/supports two half shafts, for tine left and right wheels;
they terminate in its center - but are not connected, so they can rotate at different speeds; each half shaft extends to an inboard disc-brake, then a a joint to form a complete axle.
Since there is no "direct drive" in the TATRAN - all gear ratios are indirect ., ,, r . , , w ..... .,, r r. _. ..w,.4d~.:, ..,. q.rk.;>a'y:v . ".bYV W.W .
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~ As each wheel is driven through a separate torque converter. Full power is applied to each wheel at all times, which means, that in turns in wheel will be able to rotate at different speeds - but with a full power application TATRAN - AUTOMAT_I(:
~4, or 6 Speeds - Gear Drive) TOP VIEW
1. The front of the engine 2. Fluid coupling with a reduction gear - which multiplies the ratios in the main gearboxes and a provision for reverse rotation 3. Small pinion gear - drives the TATRAN transmission 4. Large gear, acts as a speed reduction gear - and is installed between the left and right converters 5. & 5 - left and right converters - with impellers mounted back-to-back(and supplemented with stators, turbines, clutches, etc - which are not shown) 6. & 6 - right and left gear boxes - each with 3 gears - shifting simultaneously on both sides of the TATRAN
7. Two outside bearings and partitions supporting the gearbox, torque converter and the half shaft; the same is repeated on the opposite side, for a total of 4 8. Two inside bearings and main partitions of TATRAN, with the left and right bearings, supporting the torque converters and the main driving wheel. In total, there are 6 (six) supporting partitions with bearings.
9. Left half axle, terminating in the center - and exiting the transmission case for mounting of the inboards disc-brakes and a joints 10. Right half axle going in the opposite direction - but completely 'independent of the left half axle Note: this figure shows a dual 3 + 3 speed gearbox; should only 4 speed by needed, this will require only 2 + 2 speeds which will make the gearbox shorter and the whole transmission narrower.

TATRAN - AUTOMATIC
(4, OR 6 Gears - Chain Drive) FRONT VIEW
This Figure shows also a 4 , or 6 gear TATRAN Automatic gearbox but the power transmitted from the engine is accomplished by a chain - and the engine is parallel to the front axle, as it is quite common in today's vehicles. The size of the main power transmission gear can also be easily adjusted to the requirements on hand.
1. the central speed reduction wheel, driven by a chain - engine's driving is not shown. The wheel is attached to both the right and left converters 2. two central bearings - only the left one is shown 3. outside housing of the left torque converter 4. internal components of the left torque converter. It shows, how its front forms the left central TATRA,N bearing supporting the Left half shaft, and part of the entire assembly 5. left half shaft 6. right half shaft - each of them can turn at different speeds in turns, as they are driven by two separate torque converters TATRAN - AUTOMATIC
~,4, or 6 Gears - Chain, or Gear Drive) FRONT VIEW
This figure shows the TATRAN Automatic, with 4 or 6 speeds, that could be driven either by a chain - or gears. If used in FWD vehicle, the engine would like be parallel to the transmission.
Of note is a massive, central. single cross-shaft that extends almost across 75% of the entire width of the transmission and acts as structural component. for the entire TATRAN
assembly The "cross-shaft" could likely be either cast, or machined from a single piece of steel; its center supports the large reduction wheel, which is flanked by two, back-to-back impellers of the torque-converter.. These act a stabilizer, adding further rigidity to this central component.
_... ...~ , _._ _,. ,z .F_._~«~~~:~~~~~.~~~._ ~-~~~--=z.~ -PV..______ _ _.__ ___~. _.____ 1. center reduction wheel and chain, leading to the engine 2. the left side of the torque-converter exposes the shape of the left impeller that strengthens the shaft 3. right-hand half of the central shaft - illustrates the support of the impeller, and shows the length of the shaft, which extends all the way to the center supports of TATRAN
4. outside case of TATRAN
5. left-hand side of the "center support", showing the vertical wall with a bearing that supports the left turbine and the entire torque-converter assembly 6. left-hand side of the vertical wall that goes down to meet the tubular extension of the turbine and the solid end of the central shaft; it forms a three-in-one bearing 7. the right-hand support wall of TATRAN - duplicating the left one 8. & 8 the left and right gearboxes, enclosing the clutches and 3 forward gears , transmitting the power to the wheels 9. & 9 - right-and-left half shafts, inserted into the central cross shaft -where they rotate freely. The power to the half shafts is delivered through the gearboxes in 8.
THE RESULTS
By-and-large, in general terms, the TATRAN-Automatic transmissions meet the objectives staked out by Attain Technology: the delivered designs are substantially smaller, lighter and I will save the producer a great deal of money. The only features missing are 1 ) a direct drive, which locks all hydraulics from the power train and 2 a limited-slip differential. However, the latter one is being more-and-more replaced by stability and traction control features, which rely guite heavily on vehicle's dynamic sensors and a momentary application of brakes.
SUMMARY
Even before the turn of the millennium the automatic transmissions were subjected to new pressures - and called to overcome a variety of new challenges. Namely:
1. the units should be smaller and lighter - and work well in confined spaces 2. they should be produced at lower costs 3. they should be able to sustain an ever- higher BHP and torque 4. they should work well - with no maintenance- for at least 150,000 km, or longer.
Vis-a-vis all these big challenges, Attain Technolo~v Inc. has developed the TATRAN
transmissions, suited for the new CVT's and gear-type automatics -capable to reduce engine revolutions before they enter into the transmission - and then re-distributing them to the left-and-right driying heels, so that its life-expectancy is ~reatly increased. On top of that, the heave differential with its final drive has been eliminated and replaced with new components uerformin~ the same function.
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Claims (5)

1. In one single move - that may be termed "revolutionary" - Attain Technology has re-arranged the order in which the engine power is delivered to the driving wheels of vehicles with automatic transmission for about the last 60 years and in the recently introduced continuously variable transmissions, resulting in the elimination of the 'final drive', or differential from the power train in all vehicles using these types in transmissions - and thus saving a great deal of weight and generating large savings in production.

2. By reducing the engine speed "at the source" and feeding a reduced amount of RPM's into the transmission, it greatly increases the reliability and life-expectancy in both the automatic transmissions and the CVT's.

3. While the differential, per se, has been eliminated, its function to regulate the different wheel speeds in turns is maintained either by two torque converters, and/or by computer controlled wheel-RPM counters.

4. The TATRAN can accommodate the ever-increasing power-and torque demands imposed by more potent engines, because its internal design splits the incoming power to the left-and-right driven wheels, which increases its potential to handle the new demand

5. In the TATRAN-CVT, the addition of a single belt with its spools can double the transmission's power-handling capacity, while the differential housing is still absent.