7/28/2019 2010-09 - Opti-Mizing Wind Gear Production

1/6

26 SEPTEMBER | 2010

OPTI-mIzIng WIndgear PrOducTIOn

The cOrnIelds arOund Yorktown, Indi-anaabout 40 miles rom Indianapolisareamong the most ertile ound anywhere in theUnited States. Its also the perect environmentor cultivating another kind o business , so itshere that Brevini Wind USA has set down deeproots with a $50-million, 100,000 square-oot

ultramodern acility eaturing North Americasonly 6.4 MW test bench or the production omain gearboxes or 0.9 to 3.5 MW wind tur-bines. This, o course, is the size range typical-ly ound in most o todays land-based applica-tions in the region. I you think that BreviniWind is betting the arm on the U.S. windpower market, youd be right. Ater all, windturbine deployments in North America are

expected to exceed 40,000 units between 2010and 2015. While Europe dominated the worldmarket or wind turbines ive years ago with70 percent o new capacity, today the U.S. andChina account or 62 percent o new capacity,with Europe ollowing at 27 percent.

Beginning in November o this year the new

acility will oer many advantages to wind tur-bine customers seeking to penetrate the boom-ing North American marketplace, according toManaging Director Dr. Jacopo Tozzi. Mosto the major wind turbine manuacturers arebased in Europe, so the logistical beneits osourcing gearboxes locally through BreviniWind USA will be signiicant or them goingorward, he says. We are already seeing evi-

Highly productive new Gleason gear cutting

and fne fnishing technologies are helpingBrevini Wind USA to meet its ambitious

gearbox production goals.

By Michael Hayes

mi hy i pit o hy mkti, wi pt t go copotio.

go oi to www.o.o. ao viit Bvii Wi t www.bviiwi.o.

7/28/2019 2010-09 - Opti-Mizing Wind Gear Production

2/6

windsystemsmag.com 27

dence o this, in act, with a large order romFinnish wind turbine manuacturer WinWinDor their 3MW wind turbines.

The gears or WinWinDs gearboxes, andBrevini Winds other customers, will all beproduced by Gleason machines employ-ing new technologies that simply didnt ex-

ist a year or two ago. Tozzi believes that hiscompanys investment in these new Gleasontechnologies and processes will help the com-pany to quickly become a major player in theproduction o a new generation o highly re-liable, lightweight, and eicient wind powermain gearboxes, giving the company a de-cided competitive advantage going orward.Brevini Group, and the Brevini Power Trans-

i. 2:I o piio potio: aotOPTI grInd vitio ow jt t twoot w wit ii k o pt tt itoy. Ti vitio t i i qi, op to iiovtioy wit i w.

i. 1:mxi OPTI grInd potivity: aby o t b w o io toot k itoy, op totypi o i w oi two kt o. T t w oy i t oiii, wit t i ii koiitio ito t w.

i. 3:mxi OPTI grInd ii qity:a ti vitio two ot w wit iv it i to o i k opt tt; t t i w, ow, wit xty i it i, ii t it k.

7/28/2019 2010-09 - Opti-Mizing Wind Gear Production

3/6

28 SEPTEMBER | 2010

mission division in particular,is no stranger to wind power,having produced some 60,000pitch and yaw systems orwind turbines over the years,Tozzi explains. Our division,

Brevini Wind, was establishedtwo years ago in order to con-centrate on the design, devel-opment, testing, and manu-acture o main gearboxes orwind turbine applications.

This, o course, is one o themost challenging applicationsor gears, given the high anddynamic loads and the needor extreme reliability. In or-der to better understand how

i. 4: a xp

o Bvii two-

t pty

box, i o

xptio ibiity

wit it o-

opt ipovii oiby

pow.

i. 5: go P2400g poi i iv Bvii pity to p, wit pbiity to by

o t ti to po it xt wit oti it p to 2.4 t y qit o IsO g 3 o btt.

7/28/2019 2010-09 - Opti-Mizing Wind Gear Production

4/6

windsystemsmag.com 29

inishes better than 0.2 microns; a inish two to three times thelevel that is generally achievable with proile grinding alone,and so accurate that no additional processes are required atergrinding.

According to Gleason Director o Product Management,Grinding Solutions, Dr. Antoine Trich, or the irst time OPTI-GRIND solves the dilemma that every gear manuacturer aces:how to achieve, with optimum eiciency, both highly desirable

productivity gains and exceptional accuracies. Wind powergear manuacturers can o course achieve high productivity byusing a coarse-grit grinding wheel that will remove a suicientamount o material when roughing, but these wont deliver therequired ine surace inishes, Trich explains. Conversely, aine-grit wheel can be used to produce an excellent surace in-ish, but at the expense o productivity. As a result, grindingwheels are generally used that are a compromise solution, de-livering reasonable levels o productivity and accuracy, but well

our competition was meet-ing these challenges I had theopportunity to tour many otheir plants in Europe, China,and India. Almost withoutexception, the machines theywere using or gear produc-tion were made by Gleason.

By November two newGleason proile grinding ma-chinesmodels P1600G andP2400Gand two Gleasonhobbing machines, modelsP1600 and P2400, will be upand running at the BreviniWind USA acility, produc-ing all o the gears ound ina series o new generationtwo-stage planetary gearbox-

es. These include ring gearswith diameters as large as 2.2meters and accuracy require-ments as high as ISO Grade 6or better, and smaller gears oISO Grade 5 or better. Theseclassiications are typical ogears or wind turbine appli-cations, although the Gleasonproile grinders can actuallydeliver even ISO Grade 3 or

better, i required.These new planetary gear-

boxes can produce reductionratios o up to 37:1 with up to98 percent eiciency, while atthe same time reducing over-all size and weight by 25 per-cent as compared to competi-tive models. But perhaps mostimportantly, Brevini Wind willgain an enormous competi-

tive advantage by producingthese gears much aster, moreaccurately, and using ewermachines thanks to a revo-lutionary new Gleason hardinish grinding process calledOPTI-GRIND. Availableonly on the latest generationo Gleason proile grindingmachines, OPTI-GRIND willenable Brevini Wind to cut

precious minutes and evenhours out o the time typicallyneeded to proile grind one oits large gears, since produc-tivity gains o up to 40 percentare possible as compared togrinding conventionally. Inaddition, OPTI-GRIND alsocan be used to deliver surace

7/28/2019 2010-09 - Opti-Mizing Wind Gear Production

5/6

30 SEPTEMBER | 2010

below optimum levels. But with OPTI-GRINDwe can achieve both optimum productivityand surace inishes by simultaneously usingmultiple dressable grinding wheels or proilegrinding rather than just the single compro-mise grinding wheel typically used.

The new process oers end users like Brevi-ni Wind a number o variations to choose rom

to meet their speciic applications. When opti-mum productivity is desirable, or example, anassembly o three dressable wheels is used torough grind our tooth lanks simultaneously,as compared to the typical process o a singlewheel roughing only two tooth lanks at once(ig. 1). OPTI-GRIND then is used to inishgrind conventionally using just the single cen-ter wheel, which has been dressed to producethe desired surace inish and lank modiica-tions.

For planetary gears and pinions, an OPTI-GRIND variation using the two outer wheelsalone is available, with each grinding a lankon separate gear teeth simultaneously (ig. 2).This variation reduces the radial ineed re-quired as compared to grinding conventionallywith a single wheel. OPTI-GRIND provides awheel orientation that optimizes the contactangles between the grinding wheel and work-piece lank. This variation oers the largestbeneit or pinion type gears because o their

substantial proile angle variation rom toothtip to the tooth root.

In applications requiring maximum suraceinish quality, a third variation is available. Asshown in ig. 3, OPTI-GRIND uses two out-er wheels with an aggressive grit size to eachrough grind a lank on separate gear teeth,beore a middle wheel with extremely ine grit

size inishes the let and right lanks.Its important to note that OPTI-GRINDuses dressable wheels or ine inishing ratherthan the non-dressable CBN wheels used inprevious multiple-wheel proile grinding tech-niques. With OPTI-GRIND we give users thelexibility to produce a variety o highly de-sirable tooth modiications, including grind-ing o the root without burning, Trich says,noting that on the Gleason proile grinders thedressing unit is actually integral to the grind-

ing head, a unique design that helps to reducedressing times and improve accuracy and re-peatability.

Brevini Wind also hopes to gain yet anotheredge on its competition by optimizing its sotcutting operations as well, with a new Glea-son hob design called OPTI-CUT. Unlike thesolid HHS cutters normally used or large gearhobbing, the OPTI-CUT amily o roughingand inishing hobs, as well as gear gashers andshaper cutters, are very high quality assem-

7/28/2019 2010-09 - Opti-Mizing Wind Gear Production

6/6

windsystemsmag.com 31

blies consisting o either fve or six cutter bodysegments and utilizing the latest replaceable, in-dexable carbide insert technology. By using a cut-

ter with the latest carbide materials, coatings, andcutting geometries, Brevini Wind will be able torun its two new Gleason hobbers at signifcantlyhigher eeds and speedsor both external andinternal gearsand even cut dry, helping to makesignifcant reductions in total cost per workpiece.Other benefts include more-consistent tool lieand surace fnishes, while at the same time elimi-nating the time and expense needed or resharp-ening and recoating a conventional solid cutter.

Launching a company to produce main gear-

boxes or todays wind turbines is not somethingthat can be done easily or quickly, according toTozzi. We have spent a number o years layingthe groundwork with the right team o people,and a signiicant investment in new technologiesand processes, with the new Gleason machinesbeing among the most important o these. Nowwe are poised to help customers take advantageo the enormous potential that exists today andtomorrow in wind power throughout NorthAmerica.

i. 6: OPTI-cuT ob wit pb, ixb

bi it tooy iifty tot

ot p wokpi op to ovtio oi

boy tt.