correas agricolas

STANDARD

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ASAE S211.5 JUL1998 (R2008)V-belt and V-ribbed Belt Drives For Agricultural Machines

ASAE S211.5 JUL1998 „R2008…ASABE STANDARDS 2008 75

ASAE S211.5 JUL1998 (R2008)

V-belt and V-ribbed Belt Drives For Agricultural Machines

Adopted by ASAE June 1950; revised 1960, 1962; revision proposed bya joint committee representing the Rubber Manufacturers Associationand the Farm and Industrial Equipment Institute; approved by the ASAEPower and Machinery Division Technical Committee December 1968;reconfirmed December 1973, December 1978, December 1983; revisedMay 1986; revised editorially February 1987, September 1988; reaffirmedDecember 1990, December 1995, December 1996; revised editoriallyMarch 1998; revised July 1998; reaffirmed February 2003, February2008.

Keywords: Belt, V-belt

1 Purpose1.1 The purpose of this Standard is to provide sufficient technical datafor the uniform physical application of belt drives to farm machines andmobile industrial equipment. Use of this Standard will contribute to thedesign of simple and economical drives.

2 Normative referencesThe following standards contain provisions which, through reference inthis text, constitute provisions of this Standard. At the time of publication,the editions indicated were valid. All standards are subject to revision,and parties to agreements based on this Standard are encouraged toinvestigate the possibility of applying the most recent editions of thestandards indicated below. Standards organizations maintain registers ofcurrently valid standards.ANSI/ASME B46.1-1995, Surface Texture (Surface Roughness,Waviness, and Lay)ISO 1000:1992, SI units and recommendations for the use of theirmultiples and of certain other unitsRMA/MPTA IP-20, Classical Multiple V-Belts (A, B, C, D, and E CrossSections)RMA/MPTA IP-21, Double V-Belts (AA, BB, CC, and DD Cross Sections)RMA/MPTA IP-22, Narrow Multiple V-Belts (3V, 5V, and 8V CrossSections)RMA/MPTA IP-26, V-Ribbed Belts (H, J, K, L, and M Cross Sections)

3 Scope3.1 This Standard establishes acceptable manufacturing tolerances,methods of measuring, and proper application for drives using V-belts orV-ribbed belts. They may be used individually or in matched sets.3.2 This Standard is unique to agricultural belt drives and should beused in lieu of standards for industrial drives published by the RubberManufacturers Association.3.3 This Standard does not specify the load-life characteristics of belts.3.4 This Standard does not include belts for automotive accessorydrives, flat conveyor belting, flat power transmission belts, orsynchronous belts.3.5 The term belt(s) used throughout this Standard means V-belt(s) andV-ribbed belt(s).3.6 In the interest of international standardization, metric-SI units,consistent with International Organization for Standardization Standard1000, SI Units and Recommendations for the Use of Their Multiples andof Certain Other Units, are included in tables 1a through 15a.

4 Definitions4.1 effective width of V-belt groove: A groove width characterizing thegroove profile. It is a defined value not subject to tolerance and is usually

Table 1 – Nominal dimensions of cross sections, in.

Belt typeCross

section bb hb hbb1) sg

2)

Classical V-belts HA 0.50 0.31 0.41 0.625HB 0.66 0.41 0.50 0.750HG 0.88 0.53 0.66 1.000HD 1.25 0.75 0.84 1.438

Narrow V-belts H3V 0.38 0.31 0.38 0.406H5V 0.62 0.53 0.62 0.688H8V 1.00 0.91 1.00 1.125

Double-V belts HAA 0.50 0.41HBB 0.66 0.53HCC 0.88 0.69

Adjustable speed V-belts HI 1.00 0.50HJ 1.25 0.59HK 1.50 0.69HL 1.75 0.78HM 2.00 0.88HN 2.25 0.94HO 2.50 1.00HQ 3.00 1.20

V-ribbed belts J See 0.16 0.092L Fig. 0.38 0.185M 1 0.66 0.370

1)Classical and narrow V-belts are also available in the joined belt configuration asillustrated in figure 1.

2)Sg is specified pulley groove spacing (see table 7).

Table 1a – Nominal dimensions of cross sections, mm

Belt typeCross

section bb hb hbb1) sg

2)

Classical V-belts 13F 13 8 10 1516F 16 10 13 1922F 22 13 17 25.532F 32 19 21 36.5

Narrow V-belts 9FN 9 8 10 10.315FN 15 13 16 17.525FN 25 23 25 28.6

Double-V belts 13FD 13 1016FD 16 1322FD 22 18

Adjustable speed V-belts 25FV 25 1332FV 32 1538FV 38 1844FV 44 2051FV 51 2257FV 57 2463FV 63 2676FV 76 30

V-ribbed belts FPJ See 4 2.34FPL Fig. 10 4.70FPM 1 17 9.40

1)Classical and narrow V-belts are also available in the joined belt configuration asillustrated in figure 1.

2)Sg is specified pulley groove spacing (see table 7).

located at the outermost extremities of the straight side walls of thegroove. For all V-belt measuring pulleys and for most machined-typepulleys, it coincides with the actual top width of the groove withinreasonable tolerances.4.2 effective diameter of V-belt pulley: The diameter of the pulley atthe effective width of the pulley groove. (Formerly designated Effectiveoutside diameter.)4.3 effective diameter of V-ribbed pulley: The outside diameter of thepulley as a defined value at the specified pulley groove dimensions(without tolerances).4.4 effective length: The length of a line circumscribing a belt at thelevel of the effective diameter of the measuring pulleys with the belt at aprescribed tension.4.5 pitch width: The width of the belt at its neutral zone.4.6 pitch width of groove: That width of the pulley groove which hasthe same dimension as the pitch width of the belt used with this pulley.

Figure 1 – Belt types

ASAE S211.5 JUL76

4.7 pitch diameter of pulley: The diameter of the pulley at the pitchwidth of pulley groove.4.8 speed ratio and belt speed: Speed ratio is the ratio of the pitchdiameter of the pulleys; generally expressed as a number equal to orgreater than unity. Belt speed is the linear speed of the belt calculatedusing the pitch diameter of the driver pulley.4.9 installation allowance: A design length factor permitting theunforced installation of a belt (see tables 12 through 15).4.10 take-up allowance: A design length factor to permit sufficienttensioning over the life of the drive (see tables 12 through 15).4.11 measuring pulleys: Pulleys used for determining the effectivelength of a belt (see tables 5 and 6 for dimensions).4.12 ‘‘y’’ center distance: The center distance between measuringpulleys used to determine the effective length of a belt (see clause 7.1 forprocedure).4.13 clutching allowance: A design length factor to facilitate the beltdrive systems operation as a clutch (see clause 9.5).

5 Cross sections5.1 Nominal dimensions of belt cross sections for agricultural machinesare shown in tables 1 and 2. Because of different constructions andmethods of manufacture, the cross-sectional shape, dimensions, andincluded angle between the sidewalls may differ among manufacturers.However, all belts of a given cross section shall operate interchangeablyin standard grooves of the same cross section, but belts of differentmanufacturers should never be mixed on the same drive (see tables 7through 9).

6 Available lengths6.1 The length ranges for agricultural belts are shown in tables 2 and 2a.

Figure 2 – Relationship between sheave or pulley outside diameter and thecorresponding effective diameter

1998 „R2008… ASABE STANDARDS 2008


Table 2 – Effective length ranges, in.

V-Belts

V-Ribbed BeltsClassical1) Narrow1) Adjustable speed Double-V

HA 25.0–130.0 H3V 25.0–140.0 HI 40.0–125.0 HAA 50.0–130.0 J 18.0–100.0HB 30.0–300.0 H5V 50.0–355.0 HJ 50.0–160.0 HBB 50.0–300.0 L 50.0–145.0HC 55.0–365.0 H8V 100.0–600.0 HK 60.0–180.0 HCC 85.0–365.0 M 90.0–365.0HD120.0–365.0 HL 70.0–200.0

HM 80.0–200.0HN 85.0–200.0HO 90.0–200.0HQ 90.0–200.0

1)Includes joined belts.

Table 2a – Effective length ranges, mm

V-Belts

V-Ribbed BeltsClassical1) Narrow1) Adjustable speed Double-V

13F 635–3300 9FN 635–3560 25FV 1020–3175 13FC 1270–3300 FPJ 455–254016F 760–7620 15FN 1270–9020 32FV 1270–406522F 1400–9270 25FN 2540–15240 38FV 1525–4570 16FD 1270–7620 FPL 1270–368532F 3050–9270 44FV 1780–5080

51FV 2030–5080 22FD 2160–9270 FPM 2285–927057FV 2160–508063FV 2285–508076FV 2285–5080

1)Includes joined belts.

Figure 3 – Diagram of a fixture for measured belts

Table 3 – Effective length tolerance, in.

Effective length range Effective length tolerance

Up through 51 60.40Over 51 to and incl. 98 60.50Over 98 to and incl. 124 60.60

Over 124 to and incl. 157 60.80Over 157 to and incl. 197 61.00Over 197 to and incl. 248 61.25Over 248 to and incl. 315 61.60Over 315 to and incl. 390 62.00

Table 4 – Limits of difference in effective length for matching sets, in.

Effective length range

Matching limits for one set

Normaltensile

modulus

Hightensile

modulus1)

Up through 54 0.16 0.08Over 54 to and incl. 111 0.24 0.12Over 111 to and incl. 236 0.39 0.20Over 236 to and incl. 390 0.63 0.24

1)Examples of high tensile modulus belts are those containing aramid, fiberglass,or steel cable reinforcement.

Figure 4 – Measuring belt ride, V-belt

Table 3a – Effective length tolerance, mm

Effective length range Effective length tolerance

Up through 1300 610Over 1300 to and incl. 2500 613Over 2500 to and incl. 3150 616Over 3150 to and incl. 4000 620Over 4000 to and incl. 5000 625Over 5000 to and incl. 6300 632Over 6300 to and incl. 8000 640Over 8000 to and incl. 10000 650

Table 4a – Limits of difference in effective length for matching sets, mm


Matching limits for one set

Normaltensile

modulus

Hightensile

modulus1)

Up through 1375 4 2Over 1375 to and incl. 2820 6 3Over 2820 to and incl. 6000 10 5Over 6000 to and incl. 10.000 16 6

1)Examples of high tensile modulus belts are those containing aramid, fiberglass,or steel cable reinforcement.

Figure 5 – Measuring belt ride, double-V belt

ASAE S211.5 JUL78

Figure 6 – Measuring belt ride, V-ribbed belt

tive length and belt ride (see figure 7)

r Diameterover balls

or rods60.005

in.

Groovedepthhg ,min.in.

Totalmeasuring

forceper belt,

lb

Maximum rideposition of belt

with respect to topof groove, in.

Not joined Joined

3.499 0.490 65 0.10 0.185.181 0.580 100 0.10 0.208.536 0.780 190 0.10 0.25

11.996 1.060 405 0.12 0.283.499 0.490 65 0.035.181 0.580 100 0.038.536 0.780 190 0.034.203 0.340 100 0.10 0.208.633 0.590 225 0.12 0.25

17.083 0.990 500 0.16 0.307.225 0.813 180 0.16

10.601 0.938 290 0.1610.879 1.000 405 0.1811.158 1.125 560 0.2011.266 1.188 740 0.2014.558 1.339 740 0.2214.836 1.456 740 0.2215.519 1.575 740 0.22

ommended for production pulleys. The dimensions in this table reflect previousand to assure correlation of length measurement.

ctive length and belt ride (see figure 7)

r Diameterover balls

or rods60.10

mm

Groovedepthhg ,min.mm

Totalmeasuring

forceper belt, N

Maximum rideposition of belt

with respect to topof groove, mm

Not joined Joined

1 108.2 12 300 2.5 4.52 157.7 14 450 2.5 5.02 242.2 19 850 2.5 6.52 346.6 26 1800 3.0 7.01 108.2 12 300 0.82 157.7 14 450 0.82 242.2 19 850 0.81 104.3 8.5 445 2.5 5.12 207.8 15.0 1000 3.0 6.42 346.3 25.1 2225 4.1 7.61 150.7 20 800 4.11 187.8 23 1300 4.11 224.8 26 1800 4.61 261.7 29 2500 5.11 298.7 32 3300 5.11 336.4 34 3300 5.61 372.1 37 3300 5.61 386.5 40 3300 5.6


Table 5 – Data for use in measuring belt effec

Beltcross

section

Pulleyoutside

diameter60.005

in.

Pulleyeffectivecircum-ference,

in.

Pulleygrooveangle

a60.25

deg

Pulleygroove

top widthbg ,

referencein.

Diameteball orrod dB

60.0005in.

HA* 3.183 10.000 32 0.490 0.4375HB* 4.775 15.000 32 0.630 0.5625HC 7.958 25.000 34 0.879 0.7812HD 11.141 35.000 34 1.259 1.1250

HAA 3.183 10.000 32 0.490 0.4375HBB 4.775 15.000 32 0.630 0.5625HCC 7.958 25.000 34 0.879 0.7812H3V 3.820 12.000 38 0.350 0.3438H5V 7.958 25.000 38 0.600 0.5938H8V 15.916 50.000 38 1.000 1.0000HI 6.366 20.000 26 1.000 0.9531HJ 9.549 30.000 26 1.250 1.1875HK 9.549 30.000 26 1.500 1.4375HL 9.549 30.000 26 1.750 1.6875HM 9.549 30.000 26 2.000 1.9062HN 12.732 40.000 26 2.250 2.1250HO 12.732 40.000 26 2.500 2.3750HQ 12.732 40.000 30 2.8750

*Measuring pulley dimensions for HA and HB grooves are different than those recrecommendations so that precision measuring pulleys will not need to be replaced

Table 5a – Data for use in measuring belt effe

Crosssection

Pulleyoutside

diameter60.10

mm

Pulleyeffectivecircum-ference

mm

Pulleygrooveangle

a60.25

deg

Pulleygroove

top widthbg ,

referencemm

Diameteball orrod dB

60.01mm

13F 95.5 300 34 13 12.560.016F 143.2 450 34 16.5 15.560.022F 222.8 700 34 22.4 21.060.032F 318.3 1000 36 32.8 30.560.0

13FD 95.5 300 34 13 12.560.016FD 143.2 450 34 16 15.560.022FD 222.8 700 36 22 21.060.0

9FN 95.5 300 38 8.89 8.5060.015FN 191.0 600 38 15.24 15.0060.025FN 318.3 1000 38 25.40 25.0060.025FV 127.3 400 26 25.40 24.5060.032FV 159.2 500 26 31.75 30.5060.038FV 191.0 600 26 38.10 36.5060.044FV 222.8 700 26 44.45 42.5060.051FV 254.6 800 26 50.80 48.5060.057FV 286.5 900 26 57.00 54.5060.063FV 318.3 1000 26 63.00 60.0060.076FV 318.3 1000 30 76.20 72.5060.0

Figure 7 – V-belt measuring pulley groove

ASAE S211.5 JULASABE STANDARDS 2008

Figure 8 – V-ribbed belt measuring pulley groove

and ride of V-ribbed belts, in. (see figure 8)

Diameterball orrod dB

60.0005in.

Groovedepthhg ,min.in.

Topradius

r t

10.00520.000

in.

Maximumride positionof belt withrespect to

top ofgroove,

in.

Totalmeasuring

forceper rib,

lb

0.0625 0.082 0.008 0.10 11

0.1406 0.196 0.015 0.22 45

0.2812 0.393 0.030 0.30 100

and ride of V-ribbed belts, mm (see figure 8)

teror

B

1

Diameterover ball

or rod60.1mm

Groovedepthhg ,min.mm

Topradius

r t

10.1520.00

mm

Maximumride positionof belt withrespect to

top ofgroove

mm

Totalmeasuring

forceper rib,newtons

97.5 2.06 0.20 2.50 50

163.5 4.92 0.40 5.60 200

259.2 10.03 0.75 7.60 450

Table 7a – Pitch diameter location, 2a p, mm

Cross section Standard groove Deep groove

13F 6 141)

16F 8 1822F 12 2632F 18 36

1)Values for HA, 13F belts in RMA/MPTA combination A/B or 13C/16C grooves.

1998 „R2008… 79

Table 6 – Data for use in measuring effective lengths

Crosssection

Pulleyoutside

diameter,reference

in.

Pulleyeffective

circumference,in.

Pulleygrooveangle

a60.25

deg

Pulleygroovespacing

Sg ,in.

J 3.183 10.000 40 0.09260.001

L 6.366 20.000 40 0.18560.002

M 9.549 30.000 40 0.37060.0003

Table 6a – Data for use in measuring effective lengths

Crosssection

Pulleyoutside

diameter,reference

mm

Pulleyeffective

circumference,mm

Pulleygrooveangle

a60.25

deg

Pulleygroovespacing

Sg ,mm

Diameballrod d60.0

mm

FPJ 95.5 300 40 2.34 1.50(60.03)

FPL 159.2 500 40 4.70 4.00(60.05)

FPM 254.6 800 40 9.40 7.00(60.08)

Table 7 – Pitch diameter location, 2a p in.

Cross section Standard groove Deep groove

HA 0.25 0.531)

HB 0.35 0.71HC 0.40 1.01HD 0.60 1.43

1)Values for HA, 13F belts in RMA/MPTA combination A/B or 13C/16C grooves.

7 Method of measuring belts7.1 The effective length of an agricultural belt is determined using ameasuring fixture (fig. 3), consisting of two pulleys of equal diameterhaving standard groove dimensions (see tables 5, 5a, 6, and 6a). One ofthe pulleys is fixed in position while the other is movable along agraduated scale with a specified force applied to it. The belt is rotatedaround the pulleys at least twice to properly seat it in the pulley groovesand to determine the midpoint of the center distance range. Effectivelength of the belt is determined by adding twice the average centerdistance measured on the fixture to the effective circumference of themeasuring pulley specified in tables 5, 5a, 6, or 6a.7.2 The belt ride dimension is checked by measuring the distance fromthe top of the belt to the top of the measuring pulley groove (figs. 4, 5,and 6). Belt ride shall be within the maximum limit given in tables 5, 5a,6, and 6a. For V-belts the belt ride dimension is the only method ofdetermining proper belt fit in the groove.

8 Specifications for pulleys used with V-belts and V-ribbed belts8.1 Pulley groove dimensions8.1.1 Refer to the appropriate RMA/MPTA standard for pulley groovedimensions as follows below. Please observe that the ASAE V-beltdesignations are prefixed with an H, indicating heavy duty construction,and the belts are not to be replaced with RMA/MPTA Standard belts eventhough they are dimensionally equivalent. (This terminology does notapply to V-ribbed belts).Classical Belt Drives RMA/MPTA STD IP20Sections Sections A, B, C, D

HA, HB, HC, HD 13C, 16C, 22C, 32C13F, 16F, 22F, 32F (see clause 8.1.2)

Narrow Belt Drives RMA/MPTA STD IP22Sections H3V, H5V, H8V Sections 3V, 5V, 8V

9FN, 15FN, 25FN 9N, 15N, 25N

Double V-Belt Drives RMA/MPTA STD IP21Sections HAA, HBB, HCC Sections AA, BB, CC

13FD, 16FD, 22FD 13D, 16D, 22D

V-Ribbed Belt Drives RMA/MPTA STD IP26Sections J, L, M Sections J, L, M

FPJ, FPL, FPM PJ, PL, PM

Adjustable Speed Belt DrivesSee tables 8, 8a, 9, and 9a along with figures 9 and 10.

NOTE 1: Please consult RMA or MPTA if there is uncertainty concerningthe latest available standard.

NOTE 2: Select deep groove pulleys for ‘‘quarter turn’’ or other situationswhere belts enter pulley groove at an angle.

8.1.2 Pitch diameter location (dimension 2ap in pulley groove tables) isdependent on belt construction and pitch diameter location of the belt.Refer to table 7 for recommended values of 2ap for HA, HB, HC, HD,13F, 16F, 22F, and 32F sections.

8.2 Construction8.2.1 Pulleys used with agricultural V-belts or V-ribbed belts shall bemade of a material which is resistant to abrasion between the groove walland the belt. The material should be sufficiently close-grained to allowthe machining or forming of a smooth groove sidewall.8.2.2 Machined pulleys shall have surface finishes equal to or smootherthan the following values:

ASAE S211.5 JUL80

Maximum surface roughness height(arithmetic average)1)

Machined surface area µin. µm

Pulley groove sidewall 125 3.2Adjustable pulley sidewall 63 1.6Flat pulley rim O.D. 250 6.3Rim edges. rim O.D. 500 12.7

1)The measuring methods defined in ANSI/ASME B46.1 shall be used to deter-mine these values.

8.2.3 Pulleys formed from sheet metal shall be made so that the groovewidth and angle are uniform throughout the circumference of the pulley.The gage of the sheet metal used should be such that the groove will notdeflect under the load imposed by the belt.

8.2.4 Adjustable-speed pulleys should be so designed that the movabledisk is perpendicular to the axis of rotation at all times withoutappreciable runout or wobble. Failure to accomplish this results in anonuniform groove width, which materially reduces belt life and may setup undesirable vibration of the machine on which it is used (see tables8 and 8a).

9 Recommended design practices9.1 Pulley diameters . In designing belt drives, it should be recognizedthat the use of larger pulley diameters will result in lower bearing loadsand can result in the use of smaller and less expensive belt crosssections.

Table 8 – Dimensions for pulleys using adjustable speed belts, in.

Crosssection

Recommendedminimumoutside

diameter

Grooveanglea61deg bg bgo

1) 2a 2av

HI 7.60 26 1.00 1.65 0.30 2.84HJ 9.75 26 1.25 2.11 0.37 3.73HK 11.50 28 1.50 2.45 0.45 4.62HL 14.00 26 1.75 3.02 0.52 5.52HM 16.00 26 2.00 3.48 0.60 6.41HN 17.75 26 2.25 3.94 0.68 7.36HO 19.25 26 2.50 4.41 0.75 8.27HQ 21.00 30 3.00 4.92 0.90 8.30

1)bgo is calculated to provide for a clearance of 0.260 in. as shown in figure 9(dimension CL).

Table 8a – Dimensions for pulleys using adjustable speed belts, mm

Crosssection

Recommendedminimumoutside

diameter

Grooveanglea61deg bg bgo

1) 2a 2av

25FV 190 26 25.40 42.0 7.6 72.032FV 250 26 31.75 54.7 9.4 95.538FV 290 26 38.10 65.1 11.4 117.044FV 355 26 44.45 76.9 13.2 140.551FV 405 26 50.80 88.7 15.2 164.057FV 450 26 57.00 100.2 17.2 186.963FV 490 26 63.00 112.0 19.0 210.076FV 530 30 76.20 132.9 23.0 211.7

1)bgo is calculated to provide for a clearance of 6.35 mm as shown in figure 9(dimension CL).


Figure 9 – Adjustable pulley dimensions

Figure 10 – Adjustable speed companion pulley dimensions

Table 9 – Dimensions for adjustable speed companion or idler pulleys, in.(see figure 10)

Crosssection

Minimumrecommended

effectivediameter

Grooveangle

a60.5deg

bg

60.001hg

min. 2a

HI 4.75 26 1.00 0.78 0.30HJ 6.10 26 1.25 0.94 0.37HK 7.25 26 1.50 1.05 0.45HL 8.50 26 1.75 1.25 0.52HM 9.50 26 2.00 1.40 0.60HN 10.50 26 2.25 1.56 0.88HO 11.00 26 2.50 1.69 0.75HQ 12.00 30 3.00 1.97 0.90

Table 9a – Dimensions for adjustable speed companion or idler pulleys,mm (see figure 10)

Crosssection

Minimumrecommended

effectivediameter

Grooveangle

a60.5deg

bg

60.25hg

min. 2a

25FV 120 26 25.4 20 7.632FV 155 26 31.75 24 9.438FV 185 26 38.10 27 11.444FV 215 26 44.45 32 13.251FV 240 26 50.80 36 15.257FV 270 26 57.00 40 17.263FV 280 26 63.00 43 19.076FV 305 30 76.20 50 23.0


9.2 Idlers9.2.1 Idlers may be necessary on agricultural belt drives to providetake-up or to increase the arc of contact to obtain the required drivecapacity. If an idler is needed, it should be located on the slack side ofthe drive. Other factors that affect the location of the idler are itseffectiveness in belt take-up and its effect on arcs of contact.9.2.2 An idler should have its axis of rotation perpendicular to the planeof the belt strand on which it runs. The idler mounting should be strongenough to maintain this relationship at all times.9.2.3 If grooved idlers are used, the groove dimensions should be asshown in tables 9 and 9a.9.2.4 Minimum diameters recommended for idlers are shown in tables10 and 10a.9.3 Length calculations9.3.1 The approximate belt length for a two-pulley drive may becalculated using the formula:

Le52C11.57~De1de!1~De2de!2

4C(1)

where:

Le is effective length of belt;C is distance between centers of pulleys;De is effective diameter of large pulley;de is effective diameter of small pulley.

(See figure 11).

If pulley effective diameters (De and de) and belt effective length (Le) areknown, the approximate center distance between pulleys may becalculated as follows:

Figure 11 – Relation between center distance and belt length for drives withtwo pulleys

Figure 12 – Belt drive with more than two pulleys

1998 „R2008… 81

C5a1Aa22b (2)

where:

a 5 Le/420.393~De1de!;

b 5 0.125~De2de!2.

9.3.2 To determine belt length when more than two pulleys are used ona drive (figure 12), lay out the pulleys in terms of their effective diametersto scale in the position desired when a new belt is applied and firstbrought to driving tension. The length of belt shall be the sum of the

Table 10 – Minimum recommended diameters for idlers, in. 1)

Crosssection

MinimumO.D. ofgroovedinsideidler

MinimumO.D. of

flatinsideidler

MinimumO.D. ofoutside

idler

Minimumfacewidthof flatidler2)

HA 2.75 2.25 4.25 1.00HAA 4.25 4.25 4.25 1.00HB 4.00 3.75 6.00 1.25

HBB 6.00 6.00 6.00 1.25HC 6.75 5.75 8.50 1.50

HCC 8.50 8.50 8.50 1.50HD 9.00 7.50 13.50 2.00H3V 2.65 NR 4.25 1.13H5V 7.10 NR 10.00 1.38H8V 12.50 NR 17.50 1.75

J 0.80 0.65 1.25 BWL 3.00 2.63 4.50 BWM 7.00 6.25 10.50 BWHI 5.50 4.50 NR 1.75HJ 6.75 5.63 NR 2.00HK 8.00 6.75 NR 2.25HL 9.25 7.75 NR 2.50HM 10.50 8.75 NR 2.75HN 11.75 9.88 NR 3.00HO 13.00 11.00 NR 3.25HQ 15.00 12.60 NR 4.00

1)NR, not recommended; BW, belt width + 0.75 in.2)For both inside and outside idlers.

ASAE S211.5 JUL82

tangents and the connecting arcs around the effective diameters of thepulleys. The length of the connecting arcs can be calculated by theformula:

Length of arc5DeA/115

where:

De is the effective outside diameter of the pulley;A is the angle in degrees subtended by the arc of belt

contact on the pulley.

e-up of agricultural belts

Table 10a – Minimum recommended diameters for idlers, mm 1)

Crosssection

MinimumO.D. ofgroovedinsideidler

MinimumO.D. of

flatinsideidler

MinimumO.D. ofoutside

idler

Minimumfacewidthof flatidler2)

13F 70 57 108 2513FD 108 108 108 2516F 102 95 152 32

16FD 152 152 152 3222F 172 146 216 38

22FD 216 216 216 3832F 229 190 343 519FN 67 NR 108 29

15FN 180 NR 254 3525FN 318 NR 444 44FPJ 20 16 32 BWFPL 76 67 114 BWFPM 178 159 267 BW25FV 140 114 NR 4432FV 172 143 NR 5138FV 203 172 NR 5744FV 235 197 NR 6451FV 267 222 NR 7057FV 299 251 NR 7663FV 330 279 NR 8376FV 350 320 NR 100

1)NR, not recommended; BW, belt width + 19 mm.2)For both inside and outside idlers.


Figure 13 – Installation and tak

Table 11 – Minimum tangent lengths for 180 deg twist, in.

Cross sectionMinimum tangent

length, in.

HA 18HB 22HC 28HD 37

H3V 18H5V 28

NOTE – For all other cross sections, consult belt manufacturer.


Table 11a – Minimum tangent lengths for 180 deg twist, mm

Cross sectionMinimum tangent

length, mm

13F 46016F 56022F 71032F 940

9FN 46015FN 710

NOTE – For all other cross sections, consult belt manufacturer.

sical, joined classical and double-V belts, in.

for installation1)Allowance for

stretch and wear2)

HCHCC

HCjoined HD

HDjoined

Normaltensile

modulus

Hightensile

modulus

1.44 1.64 1.54 1.281.73 1.93 2.95 2.461.93 2.13 3.72 3.102.26 2.47 2.51 2.75 4.73 3.942.62 2.83 2.97 3.11 5.91 4.923.08 3.28 3.42 3.56 7.44 6.203.69 3.90 4.04 4.18 9.45 7.884.41 4.61 4.75 4.89 11.81 9.84

sical, joined classical and double-V belts, mm


stretch and wear2)

22F22FD

22Fjoined 32F

32Fjoined

Normaltensile

modulus

Hightensile

modulus

37 42 39 3344 49 75 6249 54 95 7957 63 66 70 120 10067 72 75 79 150 12578 83 87 90 189 15794 99 103 106 240 200

112 117 121 124 300 250

for narrow and joined narrow belts, in.


stretch and wear2)

5Vjoined 8V

8Vjoined

Normaltensile

modulus

Hightensile

modulus

1.58 1.54 1.281.87 2.32 2.47 2.95 2.462.07 2.53 2.67 3.72 3.102.40 2.86 3.00 4.73 3.942.76 3.22 3.36 5.91 4.923.22 3.67 3.81 7.44 6.203.83 4.29 4.43 9.45 7.88

5.00 5.15 11.81 9.84

1998 „R2008… 83

Table 12 – Installation and take-up allowances for clas


Allowance

HAHAA

HAjoined

HBHBB

HBjoined

Up through 51.2 1.09 1.25 1.25 1.39Over 51.2 to & incl. 98.4 1.38 1.54 1.54 1.68Over 98.4 to & incl. 124.0 1.58 1.74 1.74 1.88Over 124.0 to & incl. 157.5 1.92 2.07 2.07 2.22Over 157.5 to & incl. 196.9 2.43 2.57Over 196.9 to & incl. 248.0 2.89 3.03Over 248.0 to & incl. 315.0 3.50 3.65Over 315.0 to & incl. 393.7

NOTE – Refer to table 14 for footnote key.

Table 12a – Installation and take-up allowances for clas


Allowance

13F13FD

13Fjoined

16F16FD

16Fjoined

Up through 1300 28 32 32 35Over 1300 to & incl. 2500 35 39 39 43Over 2500 to & incl. 3150 40 44 44 48Over 3150 to & incl. 4000 49 53 53 56Over 4000 to & incl. 5000 62 65Over 5000 to & incl. 6300 73 77Over 6300 to & incl. 8000 89 93Over 8000 to & incl. 10,000

NOTE – Refer to table 14a for footnote key.

Table 13 – Installation and take-up allowances


Allowance

3V3V

joined 5V

Up through 51.2 1.09 1.20 1.44Over 51.2 to & incl. 98.4 1.38 1.49 1.73Over 98.4 to & incl. 124.0 1.58 1.69 1.93

Over 124.0 to & incl. 157.5 2.26Over 157.5 to & incl. 196.9 2.62Over 196.9 to & incl. 248.0 3.08Over 248.0 to & incl. 315.0 3.69Over 315.0 to & incl. 393.7

NOTE – Refer to table 14 for footnote key.

ASAE S211.5 JUL1998 „R2008…84 ASABE STANDARDS 2008

Table 13a – Installation and take-up allowances for narrow and joined narrow belts, mm


Allowance for installation1)Allowance for

stretch and wear2)

9FN9FN

joined 15FN15FNjoined 25FN

25FNjoined

Normaltensile

modulus

Hightensile

modulus

Up through 1300 28 30 37 40 39 33Over 1300 to & incl. 2500 35 38 44 47 59 63 75 62Over 2500 to & incl. 3150 40 43 49 53 64 68 95 79Over 3150 to & incl. 4000 57 61 73 76 120 100Over 4000 to & incl. 5000 67 70 82 85 150 125Over 5000 to & incl. 6300 78 82 93 97 189 157Over 6300 to & incl. 8000 94 97 109 113 240 200Over 8000 to & incl. 10,000 127 131 300 250

NOTE – Refer to table 14a for footnote key.

Table 14 – Installation and take-up allowances for V-ribbed belts, in.



stretch and wear2)

J L M

Normaltensile

modulus

Hightensile

modulus

Up through 51.2 0.86 1.20 1.54 1.28Over 51.2 to & incl. 98.4 1.15 1.49 1.93 2.95 2.46Over 98.4 to & incl. 124.0 1.69 2.13 3.72 3.10

Over 124.0 to & incl. 157.5 2.03 2.47 4.73 3.94Over 157.5 to & incl. 196.9 2.83 5.91 4.92Over 196.9 to & incl. 248.0 3.28 7.44 6.20Over 248.0 to & incl. 315.0 3.90 9.45 7.88Over 315.0 to & incl. 393.7 4.61 11.81 9.84

1)Allowance for installation includes the minus manufacturing length tolerance fromtable 3, the difference between the length of belt under no tension and the lengthunder installation tension, and an amount for installing the belts over the pulleyflanges without injury.

2)Allowance for stretch and wear includes the plus manufacturing tolerance fromtable 3 as well as an allowance for the stretch and wear of the belt resulting fromservice on the drive (see tables 12, 13, 14, and 15).Installation and take-up methods are shown in figure 13. In the first sketch, thecenter distance of the drive can be adjusted to furnish the necessary installationand take-up allowances. In the second sketch, the center distance is fixed, andthe allowance for installation and take-up is provided by the idler pulleys.Examples of the calculation of center distance, effective length, and installationand take-up allowances are shown in Annex A.

Table 14a – Installation and take-up allowances for V-ribbed belts, mm



stretch and wear2)

FPJ FPL FPM

Normaltensile

modulus

Hightensile

modulus

Up through 1300 22 30 39 33Over 1300 to & incl. 2500 29 38 49 75 62Over 2500 to & incl. 3150 43 54 95 79Over 3150 to & incl. 4000 52 63 120 100Over 4000 to & incl. 5000 72 150 125Over 5000 to & incl. 6300 83 189 157Over 6300 to & incl. 8000 99 240 200Over 8000 to & incl. 10,000 117 300 250

1)Allowance for installation includes the minus manufacturing length tolerance fromtable 3a, the difference between the length of belt under no tension and thelength under installation tension, and an amount for installing the belts over thepulley flanges without injury.

2)Allowance for stretch and wear includes the plus manufacturing tolerance fromtable 3a as well as an allowance for the stretch and wear of the belt resultingfrom service on the drive (see tables 12a, 13a, 14a, and 15a).Installation and take-up methods are shown in figure 13. In the first sketch, thecenter distance of the drive can be adjusted to furnish the necessary installationand take-up allowances. In the second sketch, the center distance is fixed, andthe allowance for installation and take-up is provided by the idler pulleys.

Table 15 – Installation and take-up allowances for adjustable speed belts, in.



stretch and wear2)

HI HJ HK HL HM HN HO HQ

Normaltensile

modulus

Hightensile

modulus

Up through 51.2 1.39 1.53 1.69 1.83 1.99 2.08 2.18 2.36 1.54 1.28Over 51.2 to & incl. 98.4 1.68 1.82 1.98 2.12 2.28 2.37 2.47 2.70 2.95 2.46Over 98.4 to & incl. 124.0 1.88 2.02 2.18 2.32 2.48 2.57 2.67 2.95 3.72 3.10

Over 124.0 to & incl. 157.5 2.22 2.36 2.51 2.66 2.81 2.91 3.00 3.15 4.73 3.94Over 157.5 to & incl. 196.9 2.87 3.01 3.17 3.27 3.36 3.54 5.91 4.92

1)Installation allowance on a drive using two adjustable pulleys can be neglected.2)Allowance for stretch and wear includes the plus manufacturing tolerance from table 3 as well as an allowance for the stretch and wear of the belt resulting from service

on the drive (see tables 12, 13, 14, and 15).Installation and take-up methods are shown in figures 11 and 12. In the first sketch, the center distance of the drive can be adjusted to furnish the necessary installationand take-up allowances. In the second sketch, the center distance is fixed, and the allowance for installation and take-up is provided by the idler pulley.Examples of the calculation of center distance, effective length, and installation and take-up allowances are shown in Annex A.


Table 15a – Installation and take-up allowances for adjustable speed belts, mm



stretch and wear2)

25FV 32FV 38FV 44FV 51FV 57FV 63FV 76FV

Normaltensile

modulus

Hightensile

modulus

Up through 1300 35 39 43 46 51 53 55 60 39 33Over 1300 to & incl. 2500 43 46 50 54 58 60 63 70 75 62Over 2500 to & incl. 3150 48 51 55 59 63 65 68 75 95 79Over 3150 to & incl. 4000 56 60 64 68 71 74 76 80 120 100Over 4000 to & incl. 5000 73 76 81 83 85 90 150 125

1)Installation allowance on a drive using two adjustable pulleys can be neglected.2)Allowance for stretch and wear includes the plus manufacturing tolerance from table 3a as well as an allowance for the stretch and wear of the belt resulting from service

on the drive (see tables 12a, 13a, 14a, and 15a).Installation and take-up methods are shown in figures 11 and 12. In the first sketch, the center distance of the drive can be adjusted to furnish the necessary installationand take-up allowances. In the second sketch, the center distance is fixed, and the allowance for installation and take-up is provided by the idler pulley.

9.3.3 Belt manufacturers have computer programs for calculating beltlength and will provide assistance in solving complex drive geometries.9.4 Installation and take-up (see figure 13)9.4.1 The calculated belt length (clause 9.3) shall be the effective lengthof an ideal belt under operating tension. A belt drive shall be arranged sothat any belt within the length tolerances given in tables 3 and 3a can beplaced in the pulley groove without forcing. In addition, provision shall bemade to compensate for the change in effective length caused by theseating of the belt in the pulley groove and by the stretch and wear of thebelt during its life.

9.4.2 Installation and take-up allowance specified in tables 12, 12a, 13,13a, 14, 14a, 15, and 15a shall be provided on every belt drive to ensuresatisfactory operation.9.5 Clutching belt drives. Properly designed belt drive systems can beused as a clutching mechanism. The required belt effective length isdetermined by adding the clutching allowance to the calculateddeclutched length. The clutching allowance is calculated from the formula

Figure 14 – Typical two-pulley drive with one shaft movable for take-up

)
Clutching allowance (min.)53.14 hbS u
306 deg D +(minus belt length tol.

where

hb is belt thickness (see tables 1 and 1a);u is arc of contact on clutching pulley, deg.;Minus belt length tolerance5values from tables 3 and 3a.

9.5.1 The calculated clutching allowance should be equal to or exceedthe allowance for installation given in tables 12 through 15 and 12athrough 15a.9.5.2 The drive design should provide proper belt guide(s) to permit thebelt to disengage from the driving pulley.
9.6 Cross drives, mule drives, and other twisted-belt drives
ASAE S211.5 JUL86

9.6.1 The minimum tangent length for a 180 deg twist in a belt is shownin Tables 11 and 11a. The minimum tangent length for any amount oftwist other than 180 deg can be obtained by multiplying the minimumtangent length by the fraction

degrees of twist required

180.

Adjustable-speed belts are not recommended for these drives.9.6.2 Quarter-turn drives. On quarter-turn drives, the angle of entry ofthe belt into the plane of the pulley grooves should not exceed 5 deg. Acenter distance at least 5.5 times the diameter of the large pulley isnecessary to ensure this condition where one belt is used.9.7 Specification of belt drives. In submitting a drive design problem toengineering departments of the different belt manufacturers, it is stronglyrecommended that complete information be given. Annex A providesexamples of the data needed.

fixed and idler used for take-up


Figure 15 – Two-pulley drive with centers


Figure 16 – Double-V belt drive with four pulleys on fixed centers

Annex A(informative)

Examples of the calculation of beltlength, center distance, installation and

take-up allowances, and inspection requirements

EXAMPLE 1 (Refer to figure 14)The drive consists of two pulleys; one of the shafts may be moved forinstallation and take-up. Effective diameters have been determined. Thepreferred center distance is about 20 in.

Belt length and center distance1. Substitute the effective diameters and preferred center distance in

formula [1]. The effective belt length required is 79.02 in.2. Round to the nearest tenth of an inch, or 79.0 in.3. This length substituted in formula [2] will give a center distance of

19.97 in.

Installation allowance1. From table 12 the installation allowance will be 1.54 in.2. Subtract this amount from the effective belt length of 79.0 in. to get

a length of 77.46 in.

3. This length substituted in formula [2] will give a center distance of19.16 in., the minimum center distance needed for installation ofthe belt.

Take-up allowance1. From table 12 the allowance needed for take-up is 2.95 in.2. Add this amount to the effective belt length of 79.0 in. to get a

maximum length of 81.95 in.3. This length substituted in formula [2] will give the maximum

required center distance of 21.51 in.Inspection requirementFill in the inspection requirements for the belt required in Example 1.

1. Fill in values from table 5 as follows:Tension5100 lbhg50.580 in.bg50.630 in.a532 deg.OD54.775 in.Maximum ride position of belt with respect to top of groove is 0.09in. (Note: From table 5, the effective circumference of themeasuring pulley is 15.000 in.)

2. From the effective length of 79.0 in., subtract 15.000 in. and dividethe remainder by 2 to find Y, orY5~79.0215.000!/2532.0 in.

3. From table 3, the length tolerance is 60.50 in. The tolerance ondimension Y will be equal to these length tolerances divided by 2,orTolerance on Y560.25 in.

EXAMPLE 2 (Refer to figure 15)The effective diameters have been determined. Both shafts arefixed in position and the center distance is 26.66 in. An 8.5 in.outside diameter flat idler will be used for take-up on the drive.

Belt length1. Substitute the effective outside diameters of the pulleys and the

fixed center distance of 26.66 in. in formula [1]. The resulting beltlength is 80.01 in.

2. Since the centers cannot be moved for installation, the shortestpossible belt must go on the drive with the idler out of the way.Consequently, the installation allowance must be added to the beltlength obtained above. The installation allowance from table 12 is1.73 in. This added to the length of 80.01 in. gives a requiredeffective belt length of 81.74 in.

Take-up allowancesFrom table 12, the take-up allowance needed for this belt is 2.95 in. Thisamount added to the effective belt length of 81.74 in. gives a maximumlength of 84.69 in. By one of the methods outlined above for determiningbelt length when more than two pulleys are used on a drive, locate theposition of the idler so that it will provide take-up for this length of belt.

Inspection requirements

Fill in the inspection requirements for the belt required in example 2.

1. Fill in values from table 5 as follows:Tension5190 lbhg50.780 in.bg50.879 in.a534 degOD57.958 in.Maximum ride position of belt with respect to top of groove is 0.09in. (Note: From table 5, the effective circumference of themeasuring pulley is 25.000 in.)

2. From the effective length of 81.74 in. subtract 25.000 in. and divide

ASAE S211.5 JUL88

the remainder by 2 to find Y, orY5(81.74225.000)/2528.37 in.


EXAMPLE 3 (Refer to figure 16)2. The effective diameters have been selected and shaft centers have

been located approximately. All shafts will be fixed in position andbelt take-up will be accomplished by means of a grooved idlerpulley.

Belt length1. With the idler in its ‘‘installation position,’’ use one of the methods

outlined above for determining belt length when more than twopulleys are used on a drive.

2. To find the length of belt for the drive, add to the length obtainedin step 1 the allowance for installation from table 12.

Take-up allowanceTo the length of belt for the drive, add the allowance for take-up fromtable 12. Check the drive with the idler in its maximum take-up positionto see that this length of belt can be accommodated.Inspection requirementsFill in the inspection requirements for the belt required in example 3.

1. Fill in values from table 5 as follows:Tension5190 lbhg50.780 in.bg50.630 in.a534 degOD57.958 in.Maximum ride position of belt with respect to top of groove is 0.03in. (Note: From table 5, the effective circumference of themeasuring pulley is 25.000 in.)

2. From the effective length of 176.7 in., subtract 25.000 in. anddivide the remainder by 2 to find Y, orY5~176.7225.000!/2575.85 in.

