ERGONOMICS & STYLING

iVT INTERNATIONAL 2004

ERGONOMICS & STYLING

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STEVEN CASEY

When Massey Ferguson setout to create the new MF7400 Dyna-VT agriculturaltractor, the OEM had farmore than one objective inmind. True, there was the

matter of integrating the popular FendtContinuously Variable Transmission(CVT) into the top end of the MF prod-uct line – a logical ‘transmission oftransmissions’ from one to the other ofthe two prominent Agco brands. TheOEM had a strong business case for driving Fendt’s technology leadership,particularly its Vario CVT technology,into other Agco product lines.

However, there was also the need to bring Tier II engine technology andelectronic engine-management systemsto the MF product for emissions compli-ance and to take full advantage of theFendt CVT.

“The two objectives worked prettymuch in tandem,” according to MarkPerger, Agco product manager for the7400 program. “We made the deliberatedecision to drive the technology downthrough the two brands, to capitalize onFendt CVT leadership and successes andthe broad popularity of the MasseyFerguson brand, particularly in theEuropean market. Massey Ferguson haslong been known as the ‘tractor-driver’stractor’, easy to use and a pleasure to livewith, and we wanted to bring to it theproven capabilities of the Fendt CVT.” Itmade the most sense, adds Perger, tomake all of these changes and meet allof the objectives at the same time.

The end result of the effort hasindeed been a new ‘tractor-driver’s tractor’ – a vehicle with state-of-the-artmechanicals and user interface; a tractorthat has received accolades from owners

WHAT LIES BENEATH…… is neither here nor there for the users of Massey Ferguson’s

new 7400 Dyna-VT tractor. Despite complex CVT and electronic

engine management, engineers have ensured simplicity for drivers

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ERGONOMICS & STYLING

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and operators; a tractor worthy of the‘Machine of the Year’ award recentlygranted by the German agricultural press.

Program organization “In actuality, there were 16 sub-projectswithin the overall development pro-gram,” notes Perger. As engineeringdirector and head of the 140-memberengineering team at Massey Ferguson’ssprawling Beauvais plant north of Paris,Malcolm Shute was in charge of overallengineering development. The sub-programs were organized into five units,each with a team of specialist engineersand designers given the responsibility toaddress their part of the program.

Overseeing total vehicle architectureand ensuring the co-ordination of thevarious teams was Stephane Lamperiere.Engine engineering activities wereheaded up by Jean Andiano. The teamresponsible for the rear axle, hydraulics,and integration of the Fendt CVT wasled by Andre Rateau, while YvonLeClezio led the electronics and electricsgroup – a particularly important func-tion considering the new engine-management system, CVT and accom-panying operator-control system.Changes to the front structure wereundertaken by the team led by FrancoisPottier and last, but not least, ChristopheRoudet spearheaded the engineering ofa new cab interior, controls and roof.

Having worked most recently onAgco’s Challenger MT700 and MT800tracked tractors, Dr Steven Casey,Ergonomic Systems Design, was broughtin to develop the basic workspace geo-metry for the operator station, to developlogical layouts for the panels and con-soles and, most importantly, helpdevelop a control interface for the CVTthat was easy to understand and use.‘Simplicity of operation’ was the over-riding goal for the cab interior, espe-cially the CVT.

“Long discussions took place overthe transmission’s user interface, whichchanged shape several times before thefinal design met our criteria for totalusability,” says Malcolm Shute. “Much

of the new control console design andcab layout reflect Casey’s suggestions.”

The talents of industrial designer S. Cosnier of SERA (based in Paris) weretapped to create an updated and pleas-ing style to cab interior elements andexterior features. Casey, Cosnier andMassey Ferguson engineers especiallyworked purposefully to develop a userinterface that simplified the underlyingtechnology for the operator.

CVT backgroundAround since 1997, the Fendt CVT iswidely recognized as one of the mostsignificant innovations in the industrywithin the last decade. Perfection of thetrue continuously variable transmissionhas been called the ‘Holy Grail of gear-box design’ – a system that will providegreat improvements in vehicle flexibilitywithout sacrificing efficiency, as is thecase with a traditional hydrostat.

In concept, the CVT breaks the tradi-tional link between engine speed, groundspeed and PTO speed, allowing the oper-ator to control speeds for optimum taskand fuel efficiency. Perhaps the mostsignificant breakthrough was the FendtCVT’s ability to handle high torques.

Essentially a hybrid – a combinationmechanical and hydrostat drive – it letsthe user run the engine at any rpm yetmaintain or vary speed as needed, allwhile holding fuel usage down. Longgone are the days when the operatorhad to put up with discrete steps in rpmand speed established by a set of gears.

The CVT allows the selection of anyground speed while the required PTOspeed is maintained – ideal for ‘slow’tasks that need a great deal of power. Forlight duties, with no need for full enginepower, the operator can select a highground speed while keeping rpm low,saving fuel and cutting down on noise.

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ERGONOMICS & STYLING

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The ‘continuously variable’ engineand continuously variable transmissionnow work together in a way that bettersupports the particular task of the trac-tor, all in a surprisingly compact space.

Basic instinct For the 7400’s CVT – dubbed the MFDyna-VT – the control system had to beas intuitive as possible. In the final pro-duction tractor, one finds a traditionalorange hand throttle to control fuelflow, a foot pedal and a Dyna-VT con-trol lever that looks and acts much like atraditional powershift controller.

Push the hand throttle to throttle upand pull it back to throttle down. Pushthe control handle to move forward andpull it back to slow down. Hold it in theforward position until the desired groundspeed is achieved – let go, and the trac-tor maintains that speed. Feel like con-trolling ground speed with the pedalinstead? Simple – engage ‘pedal mode’with the flick of a switch and the footthrottle controls ground speed throughthe transmission and the engine.

It all feels natural and intuitive, withvery little for the operator to learn and

memorize. Long-established controlinterface paradigms have been put togood use making the CVT and enginefunctions work together seamlessly in avery natural way for the operator. Thesystem underneath may be high-tech,but to the operator the control inputsare logical and straightforward.

Like setting the cruise control on a car,controls for setting two independentground speeds can be set, and memorizedby the tractor, by adjusting two knobson the console near the main hand con-trols. This ability to alternate betweentwo preset speeds is particularly usefulwhen working the field and turning onthe headland.

The ‘supervisor’ control knob lets theoperator optimize the relationshipbetween engine load and forward speed.Again, the control has been designedwith the task and experience of theoperator in mind. Turn the dial to thePTO symbol, or the trailer symbol, forexample to automatically optimize theengine and transmission operating char-acteristics for those particular applica-tions. This user-centered approach todesign and labeling unburdens the oper-ator and requires little or no technicalunderstanding of the underlying opera-tions of the engine and transmission.

Elsewhere on the spacious right-handconsole, hydraulic, hitch, PTO and cabsuspension controls are placed in logicallocations and and grouped according tofunction. The sweeping arc of the consolegives a powerful, user-focused feeling to

the cab overall and complements thecircular design of the front console,developed by Cosnier of SERA. Thefunctional control layouts on the frontand side consoles are placed within thecontext of an innovative interior.

Suspension and other featuresThe transmission, engine managementsystems, controls and displays are notthe only new things on the tractor.Perhaps the first thing one notices whileactually operating it is how quiet it is(an industry-low 71dB(A) in the highspec model). Also available are auto-matic air conditioning and climate con-trol; a pneumatic, swiveling, heatedseat; a suspended front axle; a dual-stagesuspended cab with user control oversuspension settings; and automatedcontrol of four-wheel drive, the differ-ential lock, and the PTO. These elec-tronic driving aids allow the user toprogram frequently performed actions,contributing to a very comfortable ridein a very user-friendly environment.

The MF 7400 actually includes sixdifferent tractors with 120hp on the7465 to 185hp on the 7495. Water-cooled, direct-injection diesels by Sisuand Perkins are available, with capaci-ties ranging from 6.0-6.6 liters. All trac-tors in the range carry the Dyna-VTstepless, continuously variable transmis-sion with a field speed range of 0.03-28km/h and a road-speed range of 0.03-50km/h. Maximum hitch-lift capacity atlink ends ranges from 7,600-9,300kg.

Feedback from early owners andoperators of the MF 7400 Dyna-VT trac-tors has been excellent, especially withregard to the tractor’s ease of operation,performance of the CVT and quiet sus-pended cab. After some initial chal-lenges ramping up to strong buyerdemand, the Beauvais plant has dramat-ically increased capacity.

Contributing to the tractor’s popu-larity was its receipt of the ‘Machine ofthe Year 2004’ award by the GermanDLV Press Group at the recentAgritechnica Show in Hannover, recog-nizing the MF 7400 Dyna-VT’s engineand transmission control system, andcategorizing the product as ‘the mostinnovative on the market, particularlyin terms of the control system’s designand ease and simplicity of use‘. The MF7400 Dyna-VT tractor is, as they say, ‘atractor-driver’s tractor’. iVT✎ Steven Casey is president, Ergonomic SystemsDesign, and is based at the company’s designstudios in Santa Barbara, California, USA

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