v-belts and pulleys for agricultural machines specifications and applications

7/28/2019 V-Belts and Pulleys for Agricultural Machines Specifications and Applications

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PHILIPPINE AGRICULTURAL ENGINEERING STANDARD PAES 301: 2000

Foreword

The formulation of this National Standard was initiated by the Agricultural Machinery

Testing and Evaluation Center (AMTEC) under the project entitled "Enhancing theImplementation of AFMA Through Improved Agricultural Engineering Standards" which

was funded by the Bureau of Agricultural Research (BAR) of the Department of Agriculture

(DA).

This Standard was reviewed by the Technical Committee for Study 2 Development of

Standards for Engineering Materials and was circulated to various private and government

agencies/organizations concerned for their comments and reactions. These standards were

presented to the Philippine Society of Agricultural Engineers (PSAE) and subjected to a

public hearing organized by the National Agriculture and Fisheries Council (NAFC). The

comments and reactions received during the presentation and public hearing were taken into

consideration in the finalization of the standards.

This Standard has been technically formulated in accordance with PNS 01:Part 4:1998Rules

for the Structure and Drafting of Philippine National Standard. It provides specifications and

proper application of drives using V-belts and does not cover manufacturing specifications.

In the preparation of this standard, the following references were considered.

ASAE S211.4:1986, V-belt and V-ribbed belt drives for Agricultural Machines

Baumeister, Theodore (ed.) 1997. Marks handbook for mechanical engineers. 10th Edition.

Mc Graw Hill Book Company, USA.

Carmichael, C. (ed.) 1950. Kents Mechanical engineers handbook. Design and production

volume. 12th Edition. John Wiley and Sons, Inc., USA.

Faires, V. M. 1969. Design of Machine Elements. Macmillan Company, New York USA.

Horton, H. L. (Ed.) 1984. Machinerys handbook. 23rd

Edition. Industrial press inc, New

York.

Richey, C. B. (Ed.) 1961. Agricultural engineers handbook. Mc Graw Hill Book Company,

USA.

ISO 3410:1989, Agricultural Machinery Endless variable-speed V-belts and groovesections of corresponding pulleys

JIS B 1854:1987, Grooved pulleys for classical V-belts

Shigley, Joseph, E. 1977. Mechanical engineering design. 3 rd Edition. Mc Graw Hill Book

Company, USA.

Mitsuboshi Design Manual


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PHILIPPINE AGRICULTURAL ENGINEERING STANDARD PAES 301:2000

Engineering Materials V-belts and Pulleys for Agricultural Machines Specifications

and Applications

1 Scope

This Standard establishes specifications and provides technical information for the proper

application of V-belts and pulleys for drives of agricultural machinery.

2 Reference

The following normative references contains provisions which, through reference in this text,

constitute provisions of this Standard:

PAES 304:2000, Engineering Materials Keys and Keyways for Agricultural Machines

Specifications and Applications

3 Application

V-belt drives are commonly used for transmitting motion and power to shafts with short

center distances, and may be operated with small pulley diameters. In addition, a number of

V-belts may be used on a multi-grooved pulley, thus making a multiple-belt drive.

4 Definitions

4.1

V-belt

flexible machine element used to transmit motion and power between two shafts, the cross

section of which is shaped roughly like a regular trapezoid outlined by the base, sides and top

of the belt

4.2

V-pulley

wheel with one or more grooved rims used to transmit motion and power by means of one or

more V-belts

NOTE:The cross section of the grooved rim is in the shape of an open-channel outlined by the base and the two slanted

sides.

4.3

V-belt drive

power transmission device, which consists of one or more V-belts, mounted on two or more

V-pulleys


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4.4

pulley diameter

the outside diameter of the pulley

4.5

pulley pitch diameter

the diameter of the pulley, which coincides with the belt pitch

4.6

belt pitch

the region in the belt that keeps the same length when the belt is bent perpendicularly to its

base

4.7

belt length

the length of the belt at the level of its pitch

4.8

speed ratioratio of the angular velocities of the pulleys making no allowance for slip and creep

4.9

belt speed

the linear speed of the belt at the level of the pulley pitch diameter

5 Belts

5.1 Nomenclature

Figure 1 shows the designation of dimensions of V-belts. Nominal dimensions of belt cross-sections for agricultural machines are shown in Table 1.

Where: bb is the top width of the belt

hb is the height of classical V-belt

Figure 1 Designation of dimensions of V-belts

40

Pitch line

b

h

b

b


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5.2 V-belt specifications

Specifications of V-belts are given in Table 1.

Table 1 Specifications of V-belts

Type of Cross section bb, mm hb, mmPower range (one or more belts),

wattsA 13 8 186-1,457

B 16 10 746-18,642

C 22 13 11,186-74,570

D 32 19 37,285-186,425

E 38 25 74,570 and up

NOTE: Because of different constructions and methods of manufacture, the cross-sectional shape, dimensionsand included angle between the sidewalls may differ among manufacturers. However, all belts of a given cross-

section shall operate interchangeably in standard grooves of the same cross-section but belts of different

manufacturers should never be mixed on the same drive.

5.3 Materials

A V-belt is constructed of cords (cotton, rayon, synthetic, or steel) and fabric impregnatedwith rubber

5.4 Marking

5.4.1 The following information shall be marked on the V-belt:

1) Type of cross section and pitch length2) Manufacturers name, trademark5.4.2 The following information shall be marked on the packaging:

1) Type of cross section and pitch length2) Manufacturers name, trademark, and address

6 V-Pulleys

6.1 Nomenclature

V-pulleys can either be single-grooved or multi-grooved and the designation of their

dimensions are shown in Figure 2.

6.2 V-pulley specification

6.2.1 Minimum recommended pulley diameters are indicated in Table 2.

6.2.2 The recommended ratio, l/dshall be at least 1.5.


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Table 2 Specifications of V-pulleys

Pulley

crosssection

Pitch diameter

x,

mm

hg,

mm

,degrees

bg,

mm E, mm d, mm l, mmMin.

recommen-ded, mm

Range(mm)

A 6565 140

Over 1403.2 12

34

38

12.5

12.89.5

+1.812-21 25-40

-0

B 115115 180

Over 1804.4 15

34

38

16.2

16.512.7

+3.816-30 32-50

-0

C 175

175 200

201 305

Over 305

5.1 20

34

36

38

22.3

22.5

22.7

17.5+3.8

30-54* 63-80*-0

D 300

300 330

331 430

Over 430

7.6 27

34

36

38

32

32.3

32.6

22.2+6.4

-0

E 450450 610

Over 61010.2 33

36

38

38.8

39.228.6

+6.4

-0

* For 3 grooved V-pulleys.

6.3 Materials

V-pulleys are generally made of cast iron, cast steel, or pressed steel. The cast materials have

good friction and wear characteristics. Pulleys made of pressed steel are lighter than cast

pulleys, but in many instances they have lower friction and may produce excessive belt wear.

Break Corners

Ddo

D

gh

gb

E

l

Do

D

x

d

hg

l

bgBreak Corners

Where bg is the top width of the pulley groove

D is the pulley pitch diameterDois the pulley outside diameterdis the bore diameter

l is the hub length

hg is the height of the pulley groove

is the groove anglex is one-half the difference between the outside diameter and the pitch

diameter

Single-grooved Multi-grooved

Figure 2 Types and designation of dimensions of V-pulleys


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6.4 Marking

6.4.1 The following information shall be marked on the pulley:

1) Type of cross section and pulley diameter

2) Manufacturers name and/or its trademark

6.4.2 The following information shall be marked on the packaging:

1) Type of cross section and pulley diameter

2) Manufacturers name, trademark and address

7 Recommended Design Practices

7.1 Pulley diameters

In designing belt drives, it should be recognized that the use of larger pulley diameters will

result in lower bearing loads and can result in the use of smaller and less expensive beltcross-sections. Pulley diameters should conform to the minimum recommended values as

specified in Table 2.

7.2 Length calculations

7.2.1 The approximate belt length for a two-pulley drive (Fig. 3) may be calculated using

the formula

( )( )

C

DDDDCL SL

SL42

2

2

+++=

.....[Eq. 1]

Where:L = length of the belt (mm)

C = distance between centers of pulleys (mm)

DL = pitch diameter of the large pulley (mm)

DS = pitch diameter of the small pulley (mm)

If this calculation results in a length, which is not of standard length (for standard lengths see

Table 10), the next longer standard length should be used and necessary correction for center

distance should be made. The center distance can be calculated from the formula:

( )16

3222

SLDDbb

C+

= ....[Eq. 2]

Where:

( )SLS DDLb += 28.64Ls = standard belt length

7.2.2 To determine the belt length when more than two pulleys are used on a drive (Fig. 4),

lay out the pulleys in terms of their pitch diameters to scale in the position desired when a

new belt is applied and first brought to driving tension. The length of the belt shall be the


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sum of the tangents (T) and the connecting arcs around the diameters of the pulleys. The

length of the connecting arcs canbe calculated by the formula:

115

ADarcofLength

= .....[Eq. 3]

Where:

D = the diameter of the pulleyA = the angle in degrees subtended by the arc of belt contact on the pulley

7.3 Selection

7.3.1 Selection of a V-belt should be based on nature of the load, type of driving unit,

horsepower rating, size of pulleys, and speeds of driving and driven units. Figure 5 serves as

an aid in the proper selection of v-belts. Tables 37 indicate the power transmitted by one

belt with velocity and size of pulley as determining factors in the power transmitted.

7.3.2 Since V-belts are used on different machines, service factors (indicated in Table 8)

should be used to correct for loading. To obtain the horsepower capacity of the drive,

multiply the rated horsepower (name plate rating) of the driving unit by the recommended

service factor.

7.4 Correction for arc of contact

Correction for arc of contact for small pulley is determined from Table 9, the arc being given

by the approximate formula:

( )

C

DDcontactofArc SL

=

60180 ......[4]

Where:DL = diameter of the large pulleyDS= diameter of the small pulleyC= center distance of drive.

Fig. 3 V-belt drive with two

pulleys

Fig 4 V-belt drive with more than

two pulleys

D

T

A


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A

B

C

D

E

5,000

4,0003,500

3,000

2,500

2,000

1,500

1,200

1,000

800

700

600

500

400

300

200

100

746

1,4

91

2,2

37

2,9

83

3,7

29

4,4

74

5,2

20

5,9

66

6,7

11

7,4

57

14,9

14

22,3

71

29,8

28

37,2

85

44,7

42

52,1

99

59,6

56

67,1

13

74,5

70

RPMof

SmallPulley

Design Power, wattsFigure 5 Belt selection chart


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Table 8 Service factors for components of farm implementsFunction of operating unit Service factor

Cutting (sickle bars) 1.5

Cutting (sickle bars with counter weight) 1.3

Cutting (reels) 1.0

Pickup attachments for combines 1.0

Feeding (front cylinder beaters, feeder rolls, draper canvas, etc.) 1.3

Threshing, chopping, etc. (combine cylinders, corn-sheller cylinders, hammer-millmotors, etc)

1.5

Separation (rear cylinder beaters, straw walkers, etc.) 1.0

Cleaning (fans, cleaning shoes, sieves, etc.) 1.0

Expelling (straw spreaders, husk blowers, etc.) 1.3

Delivery (augers, elevators, etc.) 1.3

Traction for self-propelled machines 1.3

Hydraulic system, oil pumps 1.3

Table 9 Correction factors corresponding to various degrees of contact on small pulleyArc of contact, degrees Correction factor Arc of contact, degrees Correction factor

180 1.00 133 0.87

174 0.99 127 0.85

169 0.97 120 0.82163 0.96 113 0.80

157 0.94 106 0.77

151 0.93 90 0.73

145 0.91 91 0.70

139 0.89 83 0.65

7.5 Correction for belt length

Since short belts are subjected to the action of load a greater number of times, the hours oflife of a short belt are less than those of a long belt. A correction factor for belt-length shouldbe applied to achieve a proper design of belt drives. The belt-length correction factor is

specified in Table 10.

7.6 Corrected power rating

The corrected power is obtained by getting the product of the arc correction factor, belt-length correction factor and the power rating of the selected belt from Tables 3-7 . In gettingthe power rating from Tables 3-7, an additional power to account for the speed ratio is added.

7.7 Multiple belt drives

In order to determine the number of belts to be used in multiple belt drives, the powercapacity of the drive (section 7.3.2) is divided by the corrected power rating (see section 7.6)


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Table 10 Belt length and belt length correction factorLength

designation

Outside length Belt correction factor

A B C D E A B C D E

26 713.74 - - - - 0.81 - - - -

31 840.74 - - - - 0.84 - - - -

35 942.34 960.12 - - - 0.87 0.81 - - -

38 1,018.54 1,036.32 - - - 0.88 0.83 - - -

42 1,120.14 1,137.92 - - - 0.90 0.85 - - -46 1,221.74 1,239.52 - - - 0.92 0.87 - - -

51 1,348.74 1,366.52 1,402.08 - - 0.94 0.89 0.80 - -

55 1,450.34 1,468.12 1,503.68 - - 0.96 0.90 - - -

60 1,557.34 1,595.12 1,630.68 - - 0.98 0.92 0.82 - -

68 1,780.54 1,798.32 1,833.88 - - 1.00 0.95 0.85 - -

75 1,958.34 1,976.12 2,011.68 - - 1.02 0.97 0.87 - -

80 2,085.34 - - - - 1.04 - - - -

81 - 2,128.52 2,164.08 - - 0.98 0.89 - -

85 2,212.34 2,230.12 2,265.68 - - 1.05 0.99 0.90 - -

90 2,339.34 2,357.12 2,392.68 - - 1.06 1.00 0.91 - -

96 2,491.74 - 2,545.08 - - 1.08 - 0.92 - -

97 - 2,534.92 2,570.48 - - - 1.02 - - -

105 2,720.34 2,738.12 2,773.68 - - 1.10 1.04 0.94 - -112 2,898.14 2,915.92 2,951.48 - - 1.11 1.05 0.95 - -

120 3,101.34 3,119.12 3,154.68 3,180.08 - 1.13 1.07 0.97 0.86 -

128 3,304.54 3,322.32 3,357.88 3,383.28 - 1.14 1.08 0.98 0.87 -

144 - 3,728.72 3,764.28 3,789.68 - - 1.11 1.00 0.90 -

158 - 4,048.32 4,119.88 4,145.28 - - 1.13 1.02 0.92 -

173 - 4,465.32 4,500.88 4,526.28 - - 1.15 1.04 0.93 -

180 - 4,643.12 4,678.68 4,704.08 4,749.8 - 1.16 1.05 0.94 0.91

195 - 5,024.12 5,059.68 5,085.08 5,130.8 - 1.18 1.07 0.96 0.92

210 - 5,405.12 5,440.68 5,466.08 5,511.8 - 1.19 1.08 0.98 0.94

240 - 6,129.02 6,151.88 6,164.58 6,184.9 - 1.22 1.11 1.00 0.96

270 - 6,891.02 6,913.88 6,926.58 6,946.9 - 1.25 1.14 1.03 0.99

300 - 7,653.02 7,675.88 7,688.58 7,708.9 - 1.27 1.16 1.05 1.01

330 - - 8,437.88 8,450.58 8,470.9 - - 1.19 1.07 1.03

360 - - 9,199.88 9,212.58 9,232.9 - - 1.21 1.09 1.05390 - - 9,961.88 9,974.58 9,994.9 - - 1.23 1.11 1.07

420 - - 10,723.88 10,736.58 10,756.9 - - 1.24 1.12 1.09

480 - - - 12,260.58 12,280.9 - - - 1.16 1.12

540 - - - 13,784.58 13,804.9 - - - 1.18 1.14

600 - - - 15,308.58 15,328.9 - - - 1.20 1.17

660 - - - 16,832.58 16,852.9 - - - 1.23 1.19

8 Idlers

8.1 Idlers may be necessary on agricultural belt drives to provide take-up or to increasethe arc of contact to obtain the required drive capacity. If an idler is needed, it should belocated on the slack side of the drive.

8.2 An idler should have its axis of rotation perpendicular to the plane of the belt strandon which it runs. The idler mounting should be strong enough to maintain its relationship atall times.


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8.3 Idlers may be grooved or flat (Figure 6). If grooved idlers are needed, groovedimensions should be as shown in Table 2. Grooved idlers used as inside idlers (Figure 7),should be placed close to the large pulley. Flat idlers are used as either inside or outsideidlers (Figure 7). Table 11 specifies the minimum recommended diameters for idlers.

Table 11 - Minimum recommended diameters for idlers, mm

Cross sectionMinimum O.D.

of grooved inside

idler

Minimum O.D of

flat inside idler

Minimum O. D.of flat outside

idler

Minimum facewidth of flat

idler

A 70 57 108 25

B 102 95 152 32

C 172 146 216 38

D 229 190 343 51

Grooved idler Flat idler

Figure 6 - Types of idlers

DDo

Figure 7 Positions of idlers

Driver

Driven

Outside idler

Driver

Driven

Inside idler


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Annex A

(Informative)

Example of V-belt drive selection

A.1 Given parameters

A 7,457 W split-phase motor running at 1,750 rpm is to be used to drive a rotary pump. Thepump should run at approximately 1,175 rpm. The center distance should not exceed 1,118mm. Space limits the diameter of the driven pulley to 292 mm. Determine the pulleydiameters, the belt size, and the number of belts.

A.2 Power capacity of the drive (design power)

The power capacity of the drive is the product of the nameplate rating and the recommendedservice factor given in Table 8. The obtained power capacity of the drive is:

W685,9W7,4501.3PowerDesign ==

A.3 Belt selection

A.3.1 The belt section to be used shall be section B belt (from Figure 5)

A.3.2 Thesize of the driven pulley that will be used shall be 280 mm. The diameter of the

small pulley is:

mm188rpm1,750

rpm1,175mm280 ===

S

L

LSn

nDD

Where:DL is the pitch diameter of the large pulley, mm

DS is the pitch diameter of the small pulley, mm

nL number of revolutions of the large pulley, rpm

nSnumber of revolutions of the small pulley, rpm

A.3.3 Since the limit for center distance is 1,118 mm, use 1,000 mm tentatively. Compute

for the length using the equation below.

( )( )

C

DDDDCL SL

SL42

2

2

+++=

( )( )

mm2,002.12mm1,0004

mm188mm280mm188mm280

2mm1,0002

2

=

+++=

L


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A.3.4 Since the obtained length is not a standard length, select a length from stock sizes

provided by the manufacturers. A correction for the center distance shall be made using the

following equation.

Where:

( )SLS DDLb += 28.64 lengthStandard=SL

A.4 Belt speed

The belt speed is computed as:

m/min1,033.58

1,000

rpm1750mm188

1,000

=

=

= SS

nDV

A.5 Speed ratio

The speed ratio of the drive is computed by:

1.48rpm1,175

rpm1,750===

L

S

n

nratioSpeed

A.6 Power rating of the belt

Given the velocity and the diameter of the small pulley, the closest power rating of the beltfrom Table 4 for Section B V-belts is given by:

beltW/6,607

4336,174

ratiospeedforpoweradditionalratingtableratingPower

=

+=

+=

A.7 Arc of contact

The arc of contact is computed from the equation below. The computed arc of contact given

the above parameters is 174.78 degrees. The arc of contact correction factor from Table 9 is

0.98.

( )=

= 174.78

1,000

18828060180contactofArc

( )

16

3222

SL DDbb

C

+=


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A.8 Corrected power rating

The corrected power is the product of the power rating, service factor, arc of contact

correction factor, and the belt length correction factor. For the obtained length, the belt

length correction factor is 1.00 (Table 10). Therefore, the correct power is:

beltW/6,4751.000.986,607wattsratingpowerCorrected ==

A.9 Required number of belts for multiple drives

The number of belts needed is:

Therefore use two section B belts for this drive.

belts21.496belt/W6,475

W9,685

ratingpowerCorrected

capacityPowerbeltsofNumber ===

v-belts and pulleys for agricultural machines specifications and applications

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