How to calculate the gear ratio of pulleys. Pulley calculation. Parameters of flat drive belts

Works on the bulkhead of the electric motor are nearing completion. Getting to the calculation of pulleys belt drive machine. A little bit of belt drive terminology.

We will have three main input data. The first value is the speed of rotation of the rotor (shaft) of the electric motor 2790 revolutions per second. The second and third are the speeds that need to be obtained on the secondary shaft. We are interested in two denominations of 1800 and 3500 rpm. Therefore, we will make a two-stage pulley.

The note! To start a three-phase electric motor, we will use a frequency converter therefore, the calculated rotation speeds will be reliable. If the engine is started using capacitors, then the values ​​​​of the rotor speed will differ from the nominal one in a smaller direction. And at this stage, it is possible to minimize the error by making adjustments. But for this you have to start the engine, use the tachometer and measure the current speed of rotation of the shaft.

Our goals are defined, we proceed to the choice of the type of belt and to the main calculation. For each of the produced belts, regardless of the type (V-belt, multi-V-belt or other), there are a number of key characteristics. Which determine the rationality of the application in a particular design. The ideal option most projects will use a ribbed belt. The polywedge-shaped got its name due to its configuration, it is a type of long closed furrows located along the entire length. The name of the belt comes from the Greek word "poly", which means many. These furrows are also called differently - ribs or streams. Their number can be from three to twenty.

A poly-V-belt has a lot of advantages over a V-belt, such as:

• due to good flexibility, work on small pulleys is possible. Depending on the belt, the minimum diameter can start from ten to twelve millimeters;
• high traction ability of the belt, therefore, the operating speed can reach up to 60 meters per second, against 20, a maximum of 35 meters per second for the V-belt;
• The grip force of a V-ribbed belt with a flat pulley at a wrap angle above 133° is approximately equal to the grip force with a grooved pulley, and as the wrap angle increases, the grip becomes higher. Therefore, for drives with a gear ratio greater than three and a small pulley wrap angle from 120° to 150°, a flat (without grooves) larger pulley can be used;
• thanks to light weight belt vibration levels are much less.

Taking into account all the advantages of poly V-belts, we will use this type in our designs. Below is a table of the five main sections of the most common V-ribbed belts (PH, PJ, PK, PL, PM).

Drawing of a schematic designation of the elements of a poly-V-belt in a section.

For both the belt and the counter pulley, there is a corresponding table with the characteristics for the manufacture of pulleys.

The minimum pulley radius is set for a reason, this parameter regulates the life of the belt. It would be best if you deviate slightly from the minimum diameter to the larger side. For specific task we have chosen the most common belt of the "RK" type. Minimum radius for of this type belts is 45 millimeters. Given this, we will also start from the diameters of the available blanks. In our case, there are blanks with a diameter of 100 and 80 millimeters. Under them, we will adjust the diameters of the pulleys.

We start the calculation. Let’s revisit our initial data and set goals. The speed of rotation of the motor shaft is 2790 rpm. Poly-V-belt type "RK". The minimum diameter of the pulley, which is regulated for it, is 45 millimeters, the height of the neutral layer is 1.5 millimeters. We need to determine the optimal pulley diameters, taking into account the required speeds. The first speed of the secondary shaft is 1800 rpm, the second speed is 3500 rpm. Therefore, we get two pairs of pulleys: the first is 2790 at 1800 rpm, and the second is 2790 at 3500. First of all, we will find the gear ratio of each of the pairs.

The formula for determining the gear ratio:

, where n1 and n2 are shaft rotation speeds, D1 and D2 are pulley diameters.

First pair 2790 / 1800 = 1.55
Second pair 2790 / 3500 = 0.797

, where h0 is the neutral layer of the belt, parameter from the table above.

D2 = 45x1.55 + 2x1.5x(1.55 - 1) = 71.4 mm

For the convenience of calculations and selection of the optimal pulley diameters, you can use the online calculator.

Instruction how to use calculator. First, let's define the units of measurement. All parameters except speed are indicated in millimeters, speed is indicated in revolutions per minute. In the "Neutral belt layer" field, enter the parameter from the table above, the "PK" column. We enter the value h0 equal to 1.5 millimeters. In the next field, set the rotation speed of the motor shaft to 2790 rpm. In the electric motor pulley diameter field, enter the minimum value regulated for a particular type of belt, in our case it is 45 millimeters. Next, we enter the speed parameter with which we want the driven shaft to rotate. In our case, this value is 1800 rpm. Now it remains to click the "Calculate" button. We will get the corresponding diameter of the counter pulley in the field, and it is 71.4 millimeters.

Note: If it is necessary to perform an estimated calculation for a flat belt or a V-belt, then the value of the neutral layer of the belt can be neglected by setting the value “0” in the “ho” field.

Now we can (if necessary or required) increase the diameters of the pulleys. For example, this may be needed to increase the life of the drive belt or increase the coefficient of adhesion of the belt-pulley pair. Also, large pulleys are sometimes made intentionally to perform the function of a flywheel. But now we want to fit into the blanks as much as possible (we have blanks with a diameter of 100 and 80 millimeters) and, accordingly, we will select for ourselves optimal dimensions pulleys. After several iterations of values, we settled on the following diameters D1 - 60 millimeters and D2 - 94.5 millimeters for the first pair.

08-10-2011(long ago)

There are NO pulleys on either the fan or the motor.
There is a TURNER and IRON.
What sizes of pulleys should be turned by a turner?
What RPM should the fans be?
THANKS

08-10-2011(long ago)

08-10-2011(long ago)

put a pulley 240 on the fan and on the engine 140-150.2 or 3 streams of the profile s. on the snail there will be 900-1000 revolutions if the engines are 1500. they don’t set a high frequency for large fans due to vibrations.

08-10-2011(long ago)

08-10-2011(long ago)

08-10-2011(long ago)

If speed is needed as a motor. then 1:1, if one and a half times more then 1:1.5, etc. how much you need to increase the speed by so much and make a difference in diameters.

08-10-2011(long ago)

there is a dependence on the profile of the belt
if the belt profile is "B", then the pulley should be from 125 mm or more, and the groove angle from 34 degrees (up to 40 degrees with a pulley diameter of 280 mm).

09-10-2011(long ago)

it is not difficult to calculate the pulleys. translate the angular velocity into a linear one through the circumference. if there is a pulley on the engine, calculate the length of its circumference, that is, multiply the diameter by pi, which is 3.14, get the circumference of the pulley. let's say the engine has 3000 revolutions per minute, multiply 3000 by the resulting circumference, this value shows how far the belt runs per minute of operation, it is constant, and now divide it by the required number of revolutions of the working shaft and by 3.14, get the pulley diameter on the shaft. this is the solution simple equation d1*n*n1=d2*n*n2/I explained as short as I could. I hope you understand.

09-10-2011(long ago)

09-10-2011(long ago)

03-08-2012(long ago)

28-01-2016(long ago)

thanks to Viktor ... as I understand it ... if I have 3600 rpm on the engine ... then ... on the pump nsh-10 I need a maximum of 2400 rpm ... from this I assume that ... the pulley on the engine is 100mm ... and on the pump 150mm ... or 135mm? ?? in general, rudely with errors, I hope somewhere like that ...

29-01-2016(long ago)

29-01-2016(long ago)

3600:2400=1.5
This is your gear ratio. It refers to the ratio of the diameters of your pulleys on the motor and on the pump. Those. if the pulley on the engine is 100, then the pump should be 150, then there will be 2400 revolutions. But here the question is different: are there many revolutions for NS?

Increasing the pulley diameter improves belt durability.
Tension roller.| Tensioners.| Checking the absence of a fracture in the junction of the split pulley. An increase in the pulley diameter is possible only within certain limits, determined by the gear ratio, dimensions and weight of the machine.
The coefficient cp increases with an increase in the diameter of the pulleys and the circumferential speed, as well as when using clean and well-greased belts when they work on smooth pulley bypasses, and, conversely, falls when the belts are dirty and when working on rough pulleys.
According to experimental data, with an increase in the diameter of the pulley, the coefficient of friction increases.
According to experimental data, with an increase in the diameter of the pulley, the coefficient of friction increases.
Yuon-150, which does not entail an increase in the diameters of the pulleys.
As can be seen from the previous one, as the pulley diameter increases, the bending stress decreases, which favorably affects the increase in belt durability. At the same time, the specific pressure decreases and the coefficient of friction increases, as a result of which the traction capacity of the belt increases.
With an increase in preload at the same relative load, the slip increases somewhat and decreases with an increase in the pulley diameter. When working with a reduced load, the slip decreases.
With an increase in preload at the same relative load, the slip increases slightly and d decreases with an increase in the pulley diameter.
With an increase in preload at the same relative load, the slip increases somewhat and decreases with an increase in the pulley diameter.
Most in a simple way increasing the performance of compressors is an increase in the number of their revolutions, which, with a belt drive, is achieved by increasing the diameter of the electric motor pulley. For example, the Type I compressor was originally rated at 100 rpm. However, during the operation of these compressors, it was found that the number of revolutions can be increased to 150 per minute without violating the conditions safe work.
Formula (87) shows that for belts with one rope diameter, the tension, which depends on the bending resistance, decreases with increasing pulley diameter.
Practice recent years indicates the expediency of: the use of large ratios between the diameter of the pulley and the rope (Dm / d up to 48); increasing the diameter of the pulleys; use of stronger ropes of large diameter.

A study of gears with pulleys without annular grooves: at speeds above 50 m / s, it has shown that its traction ability decreases, despite the increase in the diameter of the pulleys. The latter is explained by the appearance of air cushions in the places where the belt runs over the pulleys, which cause a decrease in the belt wrap angles and the more, the higher its speed. This is most pronounced on the driven pulley, as the driven leg of the belt is weakened, which contributes to the penetration air cushion into the contact zone of the belt with the pulley and causes it to slip.
The diameter of the pulleys of the traveling system should be 38 - 42 times larger diameter and a rope. Increasing the diameter of the pulleys helps to reduce friction losses and improve the working conditions of the rope.
Belt drives. Belt drives (fig. 47) require round, flat, and V-belts. With an increase in the diameter of the drive shaft pulley, the number of revolutions of the driven shaft increases, and, conversely, if the diameter of the drive shaft pulley is reduced, then the number of revolutions of the driven shaft will also decrease.
Technical specifications traveling blocks. Sheaves for crown blocks and traveling blocks have the same design and dimensions. Pulley diameter, profile and groove dimensions significantly affect the service life and consumption of wire ropes. The fatigue life of the rope increases with an increase in the diameter of the pulleys, since this reduces the repetitive stresses that occur in the rope when bending around the pulleys. In drilling rigs, the diameters of the pulleys are limited by the dimensions of the derrick and the convenience of work related to the removal of candles to the candlestick.
The transmission pulley diameter is one of the most important parameters for belt operation. In the tables of power transmitted by belts, to ensure a given transmission reliability, the power value is indicated depending on the smaller diameter of the transmission pulley. At first, the thrust coefficient increases sharply with an increase in the pulley diameter, then, after reaching a certain value of the pulley diameter, the thrust coefficient practically does not change. Thus, a further increase in the pulley diameter is impractical.
The cyclically changing stress that occurs in a straight belt traction body is largely determined by the magnitude of the bending stress that appears in the tape when it rolls over pulleys and bobbins. The magnitude of the bending stress can be reduced by the thickness of the belt or by increasing the diameter of the pulley. However, the thickness of the tape has minimum limit, and an increase in the pulley diameter is undesirable due to a significant increase in the weight of the winding body and the total cost of the lifting installation.
From the consideration of the table. 30 and slip curves show the following. The traction abilities of the 50X22 mm section belts do not differ significantly, despite the difference in the materials of the carrier layer. These belts give a high speed loss of the driven shaft (up to 3 5% at d 200 - 204 mm, a0 0 7 MPa and f 0 6), which increases with increasing belt tension and decreases with increasing pulley diameters. Highest value t ] 0 92 have belts with anid cord fabric and lavsan cord at d 240 - n250 mm.
The necessary pre-tensioning of the ropes is determined depending on their condition: they distinguish between a new rope and a rope that has already stretched out under load.

During the operation of the transmission, the ropes gradually lengthen and their sag increases. In this case, the decrease in stress t, due to the pre-tensioning of the rope, is partially replaced by an increase in tension from an increase in the weight of the sagging part of the rope, and to a greater extent, the greater the sag of the rope. More favorable conditions for the operation of the rope are created by increasing the diameter of the pulleys and the use of elastic ropes. With a transmission device at distances of 25 - 30 m, intermediate pulleys are installed (Fig. The use of support pulleys, as already mentioned, leads to a decrease in transmission efficiency.

Works on the bulkhead of the electric motor are nearing completion. We proceed to the calculation of the belt drive pulleys of the machine. A little bit of belt drive terminology.

We will have three main input data. The first value is the speed of rotation of the rotor (shaft) of the electric motor 2790 revolutions per second. The second and third are the speeds that need to be obtained on the secondary shaft. We are interested in two denominations of 1800 and 3500 rpm. Therefore, we will make a two-stage pulley.

The note! To start a three-phase electric motor, we will use a frequency converter, so the calculated rotation speeds will be reliable. If the engine is started using capacitors, then the values ​​​​of the rotor speed will differ from the nominal one in a smaller direction. And at this stage, it is possible to minimize the error by making adjustments. But for this you have to start the engine, use the tachometer and measure the current speed of rotation of the shaft.

Our goals are defined, we proceed to the choice of the type of belt and to the main calculation. For each of the produced belts, regardless of the type (V-belt, multi-V-belt or other), there are a number of key characteristics. Which determine the rationality of the application in a particular design. The ideal option for most projects would be to use a V-ribbed belt. The polywedge-shaped got its name due to its configuration, it is a type of long closed furrows located along the entire length. The name of the belt comes from the Greek word "poly", which means many. These furrows are also called differently - ribs or streams. Their number can be from three to twenty.

A poly-V-belt has a lot of advantages over a V-belt, such as:

• due to good flexibility, work on small pulleys is possible. Depending on the belt, the minimum diameter can start from ten to twelve millimeters;
• high traction ability of the belt, therefore, the operating speed can reach up to 60 meters per second, against 20, a maximum of 35 meters per second for the V-belt;
• The grip force of a V-ribbed belt with a flat pulley at a wrap angle above 133° is approximately equal to the grip force with a grooved pulley, and as the wrap angle increases, the grip becomes higher. Therefore, for drives with a gear ratio greater than three and a small pulley wrap angle from 120° to 150°, a flat (without grooves) larger pulley can be used;
• due to the light weight of the belt, vibration levels are much lower.

Taking into account all the advantages of poly V-belts, we will use this type in our designs. Below is a table of the five main sections of the most common V-ribbed belts (PH, PJ, PK, PL, PM).

Drawing of a schematic designation of the elements of a poly-V-belt in a section.

For both the belt and the counter pulley, there is a corresponding table with the characteristics for the manufacture of pulleys.

The minimum pulley radius is set for a reason, this parameter regulates the life of the belt. It would be best if you deviate slightly from the minimum diameter to the larger side. For a specific task, we have chosen the most common "RK" type belt. The minimum radius for this type of belt is 45 millimeters. Given this, we will also start from the diameters of the available blanks. In our case, there are blanks with a diameter of 100 and 80 millimeters. Under them, we will adjust the diameters of the pulleys.

We start the calculation. Let’s revisit our initial data and set goals. The speed of rotation of the motor shaft is 2790 rpm. Poly-V-belt type "RK". The minimum diameter of the pulley, which is regulated for it, is 45 millimeters, the height of the neutral layer is 1.5 millimeters. We need to determine the optimal pulley diameters, taking into account the required speeds. The first speed of the secondary shaft is 1800 rpm, the second speed is 3500 rpm. Therefore, we get two pairs of pulleys: the first is 2790 at 1800 rpm, and the second is 2790 at 3500. First of all, we will find the gear ratio of each of the pairs.

The formula for determining the gear ratio:

, where n1 and n2 are shaft rotation speeds, D1 and D2 are pulley diameters.

First pair 2790 / 1800 = 1.55
Second pair 2790 / 3500 = 0.797

, where h0 is the neutral layer of the belt, parameter from the table above.

D2 = 45x1.55 + 2x1.5x(1.55 - 1) = 71.4 mm

For the convenience of calculations and selection of the optimal pulley diameters, you can use the online calculator.

Instruction how to use calculator. First, let's define the units of measurement. All parameters except speed are indicated in millimeters, speed is indicated in revolutions per minute. In the "Neutral belt layer" field, enter the parameter from the table above, the "PK" column. We enter the value h0 equal to 1.5 millimeters. In the next field, set the rotation speed of the motor shaft to 2790 rpm. In the electric motor pulley diameter field, enter the minimum value regulated for a particular type of belt, in our case it is 45 millimeters. Next, we enter the speed parameter with which we want the driven shaft to rotate. In our case, this value is 1800 rpm. Now it remains to click the "Calculate" button. We will get the corresponding diameter of the counter pulley in the field, and it is 71.4 millimeters.

Note: If it is necessary to perform an estimated calculation for a flat belt or a V-belt, then the value of the neutral layer of the belt can be neglected by setting the value “0” in the “ho” field.

Now we can (if necessary or required) increase the diameters of the pulleys. For example, this may be needed to increase the life of the drive belt or increase the coefficient of adhesion of the belt-pulley pair. Also, large pulleys are sometimes made intentionally to perform the function of a flywheel. But now we want to fit into the blanks as much as possible (we have blanks with a diameter of 100 and 80 millimeters) and, accordingly, we will select the optimal pulley sizes for ourselves. After several iterations of values, we settled on the following diameters D1 - 60 millimeters and D2 - 94.5 millimeters for the first pair.

The belt drive transmits torque from the drive shaft to the driven one. Depending on it, it can increase or decrease the speed. The gear ratio depends on the ratio of the diameters of the pulleys - drive wheels connected by a belt. When calculating the parameters of the drive, you must also take into account the power on the drive shaft, its speed of rotation and the overall dimensions of the device.

Belt drive device, its characteristics

A belt drive is a pair of pulleys connected by an endless looped belt. These drive wheels are usually located in the same plane, and the axles are made parallel, while the drive wheels rotate in the same direction. Flat (or round) belts allow you to change the direction of rotation due to crossing, and the relative position of the axes - through the use of additional passive rollers. In this case, some of the power is lost.

V-belt drives due to wedge shape cross section belt allow you to increase the area of ​​its engagement with the belt pulley. A wedge-shaped groove is made on it.

Toothed belt drives have teeth of equal pitch and profile on inside belt and on the surface of the rim. They do not slip, allowing you to transfer more power.

The following basic parameters are important for the calculation of the drive:

• the number of revolutions of the drive shaft;
• power transmitted by the drive;
• the required number of revolutions of the driven shaft;
• belt profile, its thickness and length;
• calculated, outer, inner diameter of the wheel;
• groove profile (for V-belt);
• transmission pitch (for toothed belt)
• center distance;

Calculations are usually carried out in several stages.

Basic diameters

To calculate the parameters of the pulleys, as well as the drive as a whole, apply various meanings diameters, so for pulley V-belt transmission are used:

• calculated D calc;
• outer D out;
• internal, or landing D vn.

To calculate the gear ratio, the estimated diameter is used, and the outer diameter is used to calculate the dimensions of the drive when configuring the mechanism.

For a gear-belt drive, D calc differs from D nar by the height of the tooth.
The gear ratio is also calculated based on the value of D calc.

To calculate a flat belt drive, especially when big size rims with respect to the thickness of the profile, often take Dcalc equal to the outer one.

Pulley Diameter Calculation

First you need to determine the gear ratio, based on the inherent speed of rotation of the drive shaft n1 and the required speed of rotation of the driven shaft n2 / It will be equal to:

If a finished engine with a drive wheel is already available, the calculation of the pulley diameter using i is carried out according to the formula:

If the mechanism is designed from scratch, then theoretically any pair of drive wheels that satisfy the condition:

In practice, the calculation of the drive wheel is carried out based on:

• Dimensions and design of the drive shaft. The part must be securely fastened to the shaft, correspond to it in size inner hole, method of landing, fastening. The maximum minimum pulley diameter is usually taken from the ratio D calc ≥ 2.5 D ext
• Permissible transmission dimensions. When designing mechanisms, it is required to meet dimensions. This also takes into account the center distance. the smaller it is, the more the belt bends when flowing around the rim and the more it wears out. Too large a distance leads to the excitation of longitudinal vibrations. The distance is also specified based on the length of the belt. If it is not planned to manufacture a unique part, then the length is selected from the standard range.
• transmitted power. The material of the part must withstand the angular loads. This is true for high powers and torques.

The final calculation of the diameter is finally specified according to the result of overall and power estimates.

In drives various machines and mechanisms, belt drives are very widely used due to their simplicity and low cost in design, manufacture and operation. The transmission does not need a housing, unlike a worm or gear drive, it does not need ...

Grease. The belt drive is silent and fast. The disadvantages of a belt drive are: significant dimensions (in comparison with the same gear or worm gear) and limited transmitted torque.

The most widespread transmissions are: V-belt, with a toothed belt, CVT wide-belt, flat-belt and round-belt. In the article brought to your attention, we will consider the design calculation of the V-belt transmission, as the most common. The result of the work will be a program that implements step by step algorithm calculation in MS Excel.

For blog subscribers at the bottom of the article, as usual, a link to download the working file.

The proposed algorithm is implemented on materials GOST 1284.1-89,GOST 1284.3-96 and GOST 20889-80. These GOSTs are freely available on the Web, they must be downloaded. When performing calculations, we will use the tables and materials of the above listed GOSTs, so they should be at hand.

What exactly is being offered? A systematic approach to solving the issue of design calculation of V-belt transmission is proposed. You do not need to study the above GOSTs in detail, you just need to strictly follow the instructions below step by step - the calculation algorithm. If you are not constantly designing new belt drives, then over time the procedure is forgotten and, restoring the algorithm in memory, each time you have to spend a lot of time. Using the program below, you will be able to perform calculations faster and more efficiently.

Design calculation in Excel for V-belt transmission.

If you do not have MS Excel installed on your computer, then the calculations can be performed in the OOo Calc program from the Open Office package, which can always be freely downloaded and installed.

The calculation will be carried out for a transmission with two pulleys - driving and driven, without tension rollers. General scheme V-belt transmission is shown in the figure below this text. We launch Excel, create a new file and start working.

In cells with a light turquoise fill, we write the initial data and data selected by the user according to the GOST tables or refined (accepted) calculated data. In the cells with a light yellow fill, we read the results of the calculations. Cells with a pale green fill contain initial data that is not subject to change.

In comments to all cells of a columnDexplanations are given of how and from where all values ​​are selected or by what formulas are calculated!!!

We begin to “walk” along the algorithm - we fill in the cells with the initial data:

1. Transmission efficiency efficiency ( this is the efficiency of the belt drive and the efficiency of two pairs of rolling bearings) we write

to cell D2: 0,921

2. Preliminary gear ratio u’ write down

to cell D3: 1,48

3. small pulley shaft speed n1 in rpm we write

to cell D4: 1480

4. Drive Rated Power (Small Pulley Shaft Power) P1 we enter in kW

to cell D5: 25,000

Further, in the dialog mode of the user and the program, we perform the calculation of the belt drive:

5. We calculate the torque on the shaft of a small pulley T1 in n*m

in cell D6: =30*D5/(PI()*D4)*1000 =164,643

T1 =30* P 1 /(3,14* n 1 )

6. We open GOST1284.3-96, assign according to clause 3.2 (table 1 and table 2) the coefficient of dynamic load and mode of operation cp and write down

to cell D7: 1,0

7. Estimated drive power R in kW, according to which we will choose the section of the belt, we consider

in cell D8: =D5*D7 =25,000

P = P1 *Cp

8. In GOST1284.3-96, according to clause 3.1 (Fig. 1), we select the standard size of the belt section and enter

into the merged cell C9D9E9: C(B)

9. We open GOST20889-80, assign the calculated diameter of the small pulley according to clause 2.2 and clause 2.3 d1 in mm and write down

to cell D10: 250

It is advisable not to prescribe the calculated diameter of the small pulley is equal to the minimum possible value. The larger the diameter of the pulleys, the longer the belt will last, but the larger the transmission will be. A reasonable compromise is needed here.

10. Belt Linear Speed v in m/s, calculated

in cell D11: =PI()*D10*D4/60000 =19,0

v = 3.14* d1 *n1 /60000

The linear speed of the belt must not exceed 30 m/s!

11. Estimated diameter big pulley(tentatively) d2’ in mm calculated

in cell D12: =D10*D3 =370

d2’ = d 1 * u’

12. According to GOST20889-80, according to clause 2.2, we assign the calculated diameter of the large pulley d2 in mm and write

to cell D13: 375

13. Specifying the gear ratio u

in cell D14: =D13/D10 =1,500

u=d2/d1

14. We calculate the deviation of the gear ratio of the final from the preliminary delta in % and compare with the allowable value given in the note

in cell D15: =(D14-D3)/D3*100 =1,35

delta =(u-u’) / u'

The gear ratio deviation should preferably not exceed 3% modulo!

15. Large pulley shaft speed n2 in rpm we count

in cell D16: =D4/D14 =967

n2 =n1 /u

16. Large pulley shaft power P2 in kW we determine

in cell D17: =D5*D2 =23,032

P2 =P1 *Efficiency

17. We calculate the torque on the shaft of a large pulley T2 in n*m

in cell D18: =30*D17/(PI()*D16)*1000 =227,527

T2 =30* P 2 /(3,14* n 2 )

in cell D19: =0.7*(D10+D13) =438

amin =0,7*(d 1 + d 2 )

19. Calculate the maximum center-to-center transmission distance amax in mm

in cell D20: =2*(D10+D13) =1250

amax =2*(d 1 + d 2 )

20. From the resulting range and based on design features project, we assign a preliminary center-to-center transmission distance a’ in mm

in cell D21: 700

21. Now you can determine the preliminary estimated length of the belt lp’ in mm

in cell D22: =2*D21+(PI()/2)*(D10+D13)+(D13-D10)^2/(4*D21)=2387

Lp" =2*a" +(3,14/2)*(d1 +d2 )+((d2 -d1 )^2)/(4*a" )

22. We open GOST1284.1-89 and select, according to clause 1.1 (table 2), the estimated length of the belt lp in mm

in cell D23: 2500

23. We recalculate the center-to-center transmission distance a in mm

in cell D24: =0.25*(D23- (PI()/2)*(D10+D13)+((D23- (PI()/2)*(D10+D13))^2-8*((D13-D10 )/2)^2)^0.5)=757

a \u003d 0.25 * (Lp - (3,14 /2)*(d1 +d2 )+((Lp - (3,14 /2)*(d1 +d2 ))^2-8*((d2 ​​-d1 ) /2)^2)^0.5)

in cell D25: =2*ACOS ((D13-D10)/(2*D24))/PI()*180=171

A =2*arccos ((d2 -d1 )/(2*a ))

25. We determine according to GOST 1284.3-96 p.3.5.1 (tables 5-17) the rated power transmitted by one belt P0 in kW and write down

to cell D26: 9,990

26. We determine according to GOST 1284.3-96 p.3.5.1 (table 18) the wrap angle coefficient CA and enter

to cell D27: 0,982

27. We determine according to GOST 1284.3-96 p.3.5.1 (table 19) the belt length coefficient CL and write

to cell D28: 0,920

28. We assume that the number of belts will be 4. We determine according to GOST 1284.3-96 p.3.5.1 (table 20) the coefficient of the number of belts in the transmission CK and write down

to cell D29: 0,760

29. Determine the estimated required number of belts in the drive K’

in cell D30: =D8/D26/D27/D28/D29 =3,645

K"=P /(P0 *CA *CL *CK )

30. We finally determine the number of belts in the drive K

in cell D31: \u003d OKRUP (D30, 1) =4

K = round up to integer (K ’ )

We performed a design calculation in Excel for a V-belt transmission with two pulleys, the purpose of which was to determine the main characteristics and overall parameters based on partially specified power and kinematic parameters.

I will be glad to see your comments, dear readers!!!

To receive information about the release of new articles, you should subscribe to announcements in the window located at the end of the article or at the top of the page.

Enter your address Email, click on the "Receive article announcements" button, confirm the subscription in a letter that will immediately come to you at the specified mail .

From now on, small notifications about the appearance of new articles on my site will come to your mail about once a week. (You can unsubscribe at any time.)

REST can be downloaded just like that ... - no passwords!