How to calculate torque by force

M = f * l

where m is the moment of force F on the rotation axis O. if the object has the effect of anti clockwise rotation, it is defined as positive moment, otherwise it is negative moment

unit: in the international system of units, the unit of moment is Newton * meter, abbreviated as Newton * meter, symbol: n * m

in physics, moment refers to the tendency of force to make an object rotate around the axis of rotation or fulcrum. The unit of moment is Newton meter. The Greek letter is tau

moment originated from Archimedes' research on lever. Rotational torque is also called torque or torque. Torque can change the rotational motion of an object. Pushing or pulling involves forces, while torsion involves moments. The moment is equal to the cross proct of the radial vector and the applied force

equilibrium conditions:

(1) the equilibrium of a body with a fixed axis of rotation means that the body is stationary or rotates uniformly around the axis of rotation

the resultant force is zero and the resultant moment is zero at the same time, that is ∑ FX = 0, ∑ FY = 0, ∑ M = 0

torque:

(1) arm of force (L): the vertical distance from the rotation axis to the action line of force

(2) moment (m): M = L × F. The unit is n * M

(4) torque is a vector, only clockwise and counterclockwise directions are considered in middle school. It is usually specified that the torque is positive counterclockwise and negative clockwise

extended data:

according to the international system of units, the unit of energy and work is Joule, which is defined as 1 Newton meter. But Joule is not a unit of moment. Because energy is a scalar of the distance of the proct of the force points; The moment is the pseudo vector of the distance cross proct force. Of course, the same dimension is not only a coincidence; It takes 2 * PI joules of energy to apply a 1 N-M moment to a full revolution

when an object is in static equilibrium, the static force is zero and the net moment to any point is zero. For two-dimensional space, the requirement of balance is:

x, Y direction resultant force is 0, and resultant moment is 0

1. The moment of force F to point O is not only determined by the force, but also related to the position of the moment center. The moment varies with the position of the moment center

Torque: the proct of the force and the arm of force is called the torque of the force on the axis of rotation

that is: M = f * l

where m is the moment of force F on the rotation axis O. any moment that causes the object to rotate in a counter clockwise direction is defined as a positive moment, and vice versa

torque: the proct of force (f) and arm of force (L) (m). That is: M = f · L, When an object rotates around a fixed axis, there are only two possible directions for the torque, so it can be expressed by sign; Therefore, the resultant moment of several torques acting on a rotating body with a fixed axis is equal to their algebraic sum. This algebraic sum will determine whether the body is in equilibrium or non-equilibrium.

in the international system of units, the unit of torque is Newton meter. Note that it cannot be written as Joule. Joule is the unit of energy, Torque and energy are two different concepts.

in the calculation of torque, attention should be paid to the vertical distance from the axis of rotation to the line of action of the force in the plane perpendicular to the axis of rotation

Formula

driving force = torque × Gear ratio of gearbox × Final gear ratio × Mechanical efficiency ÷ Tire radius (unit: m)

summary: 1kgm = 9.8nm1lb ft = 0.13826kgm1lb ft = 1.355nm

in the case of a certain displacement, the cylinder with small cylinder diameter and long stroke pays more attention to the exertion of torque, and the rotation speed is not too high, so it is suitable for vehicles requiring large load. The cylinder with large diameter and short stroke pays more attention to the output of power, and the speed is usually higher, which is suitable for fast running vehicles. In short: power is proportional to torque × Rotate speed

calculation

power P = work W ÷ Time t work w = force F × So, P = F × s/t=F × Velocity V

here V is the linear velocity, and in the engine, the linear velocity of the crankshaft = the angular velocity of the crankshaft ω× The radius of crankshaft R is substituted into the above formula to get: power P = force F × Radius r × angular velocity ω And force F × Radius r = torque

it is concluded that power P = torque × angular velocity ω So the power of the engine can be calculated from the torque and speed

the unit of angular velocity is radian / s, which is one in radian system π It represents 180 degree

extended data

the pinion drives the big gear, assuming that the number of teeth of the pinion is 15 and the number of teeth of the big gear is 45

when the pinion rotates at 3000rpm and the torque is 20kgm, the speed transmitted to the big gear decreases by 1 / 3 to 1000rpm; However, the torque is tripled to 60 KGM. This is the basic principle that engine torque can be reced and amplified through the transmission

in automobile, the output of engine to tire is amplified twice, the first is generated by the gear of gearbox, and the second is caused by the final gear ratio (or final transmission ratio)

torque is the multiplication of the gearbox gear ratio and the final gear ratio. For example, the first gear ratio of hand-held six generation Ximei is 3.250, the final gear ratio is 4.058, and the maximum torque of the engine is 14.6kgm/5500rpm, so we can calculate that the maximum torque of the first gear is 14.6 after amplification × three point two five zero × 058 = 192.55kgm, 13 times larger than the original engine

in this case, the thrust of 470kg can be obtained by dividing the tire radius by about 0.41m. However, the above value is not the actual thrust, after all, there must be wear loss in the process of mechanical transmission, so the factor of mechanical efficiency must be taken into account

driving force = torque × Gear ratio of gearbox × Final gear ratio × Mechanical efficiency / tire radius (in meters)

horsepower is not a force, but a unit of power, defined as the amount of work that can be done in a unit time. Power is calculated from torque, and the formula is quite simple: power (W) = 2 π× Torque (nm) × Speed (RPM) / 60, after simplified calculation: power (kw) = torque (nm) × Speed (RPM) / 9549, please refer to the block article for detailed derivation. However, how to convert kW power into common horsepower

1kg force. M = 9.81n. M, which is about 10N. M

how many kg of force is generally said, such as 100kg, that is, 100kg of force

to convert the unit of torque into nm:

the kilogram of force * g (acceleration of gravity) is about 9.8

generally, the kilogram of force * 10 is converted into nm, which is easy to convert

extended data:

nm torque is the torque proced by a car

definition: unit of moment Moment: proct of force and arm)

formula: 1 Newton × 1 m = 1 nm Newton: vector, meter: scalar)

note: This is cross proct, not dot proct

In physics, torque is the size of torque, equal to the proct of force and arm of force. The international unit is nm. In addition, we can see such torque units as KGM and LB ft. because g = mg, when g = 9.8, 1kg = 9.8N, 1kgm = 9.8nm, and LB ft is the torque unit of British system, 1lb = 0.4536kg; 1ft = 0.3048m, it can be calculated that 1lb ft = 0.13826kgm. In people's daily expression, torque is often called torque (in physics, these are two different concepts). Now let's take an example: the torque of the 8th generation Civic 1.8 is 173 5Nm@4300rpm It means that the output torque of the engine at 4300 rpm is 173.5nm. How can the 173.5n power make a car with more than 1 ton run? In fact, the torque proced by the engine has to be amplified (at the cost of recing the speed at the same time), which depends on the gearbox, final drive and tires. The torque released by the engine is first amplified by the gearbox for "adjustable" torque (or reced when it exceeds the specific gear) and then transmitted to the final drive (tail teeth) for further amplification (at the same time, the speed is further reced). Finally, the driving force is released through the tires. For example, if the first gear ratio of a car is 3, the tail tooth ratio is 4, the tire radius is 0.3m, and the original torque is 200nm, the final torque on the axle becomes 200 × three × 4 = 2400nm (assuming the transmission efficiency is 100%). After dividing by the tire radius of 0.3m, the friction part between the tire and the ground has a driving force of 2400nm / 0.3m = 8000n, which is enough to drive the car
when it comes to mechanical efficiency, every gear transmission will proce a loss of power. The mechanical efficiency of manual transmission is about 95%, that of automatic transmission is about 88%, and that of universal joint of transmission shaft is about 98%. Overall, the driving force of the vehicle can be calculated by the following formula:
torque × Gear ratio of gearbox × Final gear ratio × Mechanical efficiency
driving force = ---, It is suitable for vehicles with large load. The cylinder with large diameter and short stroke pays more attention to the output of power, and the speed is usually higher, which is suitable for fast running vehicles. In short: power is proportional to torque × Speed
Add: why can engine power be calculated from torque
we know that power P = work W ÷ Time t work w = force F × So, P = F × s/t=F × Velocity V
here V is the linear velocity, and in the engine, the linear velocity of the crankshaft = the angular velocity of the crankshaft ω× The radius of crankshaft R is substituted into the above formula to get: power P = force F × Radius r × angular velocity ω And force F × Radius r = torque
it is concluded that power P = torque × angular velocity ω Therefore, the engine power can be calculated from the torque and speed
the unit of angular velocity is radian / S. in radian system, 180 degrees, torque and power are the important indicators to characterize the engine power performance
the torque output by the engine through the flywheel is called effective torque, expressed in te, and the unit is n · M. The effective torque is balanced with the resistance torque exerted on the engine crankshaft. The output power of the engine through the flywheel is called the efficiency, expressed by PE, and the unit is kW. It is equal to the proct of effective torque and crankshaft angular velocity
the effective power of engine can be measured by bench test, that is, the effective torque and crankshaft angular velocity can be measured by dynamometer, and then the effective power of starting motor can be calculated by using the following formula
PE = te · (2 Π· n / 60) / 1000 = te · n / 9550 (kw)
where te -- effective torque, n · Mn -- engine speed, R / min
the maximum value of effective torque is called maximum torque, and the maximum value of effective power is called maximum power
when a certain model is introced in newspapers, the torque and power in its technical parameters are usually the maximum torque and maximum power. The power and corresponding speed indicated on the engine nameplate are called rated power and rated speed, and the rated power is generally less than the maximum power. According to the provisions of automobile engine reliability test method, automobile engine should be able to run continuously for 300-1000h under rated conditions
as for the meaning of torque and power, generally speaking, torque is like the momentum of a hundred meter runner who squats at the starting point, is ready to go, and is ready to rush forward; And power is the ability to maintain this momentum and run faster and faster all the way to the end. Increasing the displacement of the engine can increase te and PE. In order to increase the engine displacement, the number of cylinders can be increased (such as changing 3 cylinders into 4 cylinders), or the volume of unit cylinder can be increased (such as increasing the inner diameter of cylinder)< Second, correctly understand the relationship between "torque" and "power" of the engine.
in short, the torque of the engine represents the amount of oil that can be absorbed by the cylinder in one breath, which will increase with the increase of throttle opening and engine speed, but it will not increase all the time, and it will reach the peak at a certain speed, This is what people usually call the maximum torque. If the engine speed increases again, it will graally decrease. This is the characteristic of gasoline engine and other internal combustion engines in terms of torque, and it is also the most unsatisfactory place. Power is equal to the torque times the speed, which represents the amount of oil that can be absorbed by the engine in unit time. Therefore, when the engine speed graally rises to the maximum torque point, the amount of oil absorbed in each breath and the number of suction times per unit time are increasing, so the power has been rising; When the speed exceeds the maximum torque point, although the amount of oil absorbed by each breath decreases, it increases to the maximum power point e to the small decrease and the increase of suction times; When the rotating speed exceeds the maximum power point, the decrease of the amount of oil absorbed in each breath is greater than the increase of the number of suction, so the power begins to decrease
thirdly, how to compare the advantages and disadvantages of different engines or the enhancement degree
the engine power performance indexes te and PE required by the automobile are obtained at a certain speed. Different vehicles have different requirements, different speeds (for example, trucks and cars have different speeds) and different engine speeds. Therefore, engines for different purposes have different speeds even when their effective power is equal. On the contrary, engines with equal power can not meet the requirements of all models, It is also necessary to consider the power and torque at the same time to see the corresponding speed, so as to fully see whether the engine's dynamic performance indicators te and PE meet the requirements< However, TE and PE can not be directly used to evaluate the advantages and disadvantages of engines with different displacement, that is to say, the engine with high power and torque is not good or the engine with high strength, but the power and torque per unit cylinder working volume
TL and PL are the torque and power per unit cylinder working volume. Only by using these two indicators can we compare the advantages and disadvantages of different engines or the degree of enhancement
the range of TL and PL of automobile engine:
gasoline engine: TL = 600kpa-1000kpa, PL = 22KW / l-55kw / L
diesel engine: TL = 600kpa-900kpa, PL = 11kw / l-26kw / L
under rated working conditions, the power generated by the working volume of engine per liter cylinder is called liter power
PL = PE / (VH · I) (kW / L) where: VH is the working volume of cylinder (L) I is the number of cylinders
The liter power indicates the utilization rate of working volume of unit cylinder. The larger PL is, the greater the power of working volume of unit cylinder is. When the engine power is constant, the larger PL is, the smaller the engine is and the smaller the material quality is
there are four ways to increase the power up:
(1) increasing the amount of charge requires air for fuel combustion, and it is more difficult for air to enter the cylinder than fuel. Using supercharging technology or improving the ventilation process (such as recing the intake resistance) can increase the inflation rate
(2) improve the quality of mixing gas and combustion. Under a certain amount of air, the air and oil are mixed evenly, the combustion is sufficient, and the heat supply per unit cylinder volume is increased
(3) only by improving the mechanical efficiency and recing the mechanical loss can the effective power output be increased. Recing the mechanical loss is mainly to rece the friction loss of each friction pair, followed by recing the power consumption and pumping loss of auxiliary mechanism
(4) properly increasing the speed is mainly to increase the frequency of work (or inflation), that is, to increase the amount of inflation per unit time. However, in addition to the mechanical strength, the increase of engine speed will rece the charge per cycle, increase the mechanical loss, and make the combustion process difficult to organize. That is to say, the increase of engine speed will rece the PE, so the increase of engine speed should be moderate

Torque:

torque is a special kind of torque that makes an object rotate. Engine torque refers to the engine torque output from the crankshaft end. To explain what you don't understand, to put it bluntly, it's the force you add multiplied by the distance from the force point to the axis you twist, so the torque w = FXL. Here, the unit of F is cattle. So force F = torque / L< br />

Torque calculation method

divide the torque by the wheel radius. From the engine horsepower torque output curve, we can find that there is a relative torque value at each speed. How can these values be converted into the actual driving force of the car? The answer is very simple, that is, divide by a length to get the force data. For example, a 1.6-liter engine can exert a maximum torque of about 15.0 kg · M. at this time, if the 185 / 60R14 tire is directly connected with a radius of about 41 cm, the propulsion force exerted by the wheel is 15 / 0.41 = 36.6 kg (in fact, the kilogram is not a unit of force, but a unit of mass, which must be multiplied by the acceleration of gravity of 9.8 m / s and 178; The standard unit of force is Newton

36kg push the weight of one ton? Moreover, the engine speed of thousands of revolutions is unlikely to be just the tire speed. The use of gears of different sizes can rece the rotation speed and amplify the torque at the same time. Because the circumference ratio of the gear is the radius ratio, when the power is transmitted from the pinion to the big gear, the ratio of the rection of the rotational speed and the magnification of the torque are exactly equal to the ratio of the number of teeth of the two gears, which is the so-called gear ratio

for example,

the pinion drives the big gear, assuming that the number of teeth of the pinion is 15 and the number of teeth of the big gear is 45

when the pinion rotates at 3000rpm and the torque is 20kgm, the speed transmitted to the big gear will be reced to 1 / 3 and become 1000rpm; However, the torque is tripled to 60 KGM. This is the basic principle that engine torque can be reced and amplified through the transmission

in automobile, the output of engine to tire is amplified twice, the first is generated by the gear of gearbox, and the second is caused by the final gear ratio (or final transmission ratio). The total magnification of torque is the multiplication of the gearbox gear ratio and the final gear ratio. For example, the first gear ratio of hand-held six generation Ximei is 3.250, the final gear ratio is 4.058, and the maximum torque of the engine is 14.6kgm/5500rpm, so we can calculate that the maximum torque of the first gear is 14.6 after amplification × three point two five zero × 058 = 192.55kgm, 13 times larger than the original engine. At this time, dividing by the tire radius of about 0.41m, we can get the thrust of about 470kg. However, the above value is not the actual thrust, after all, there must be wear loss in the process of mechanical transmission, so the factor of mechanical efficiency must be taken into account

when it comes to mechanical efficiency, every gear transmission will proce a power loss. The mechanical efficiency of manual transmission is about 95%, that of automatic transmission is about 88%, and that of universal joint of transmission shaft is about 98%. On the whole, the driving force of a car can be calculated by the following formula: torque × Gear ratio of gearbox × Speed ratio of final drive × Mechanical efficiency / tire radius

formula calculation

formula

driving force = torque × Gear ratio of gearbox × Speed ratio of final drive × Mechanical efficiency ÷ Tire radius (unit: m)

calculation

why can engine power be calculated by torque

power P = work W ÷ Time t work w = force F × So, P = F × s/t=F × Velocity V

here V is the linear velocity, and in the engine, the linear velocity of the crankshaft = the angular velocity of the crankshaft ω× The radius of crankshaft R is substituted into the above formula to get: power P = force F × Radius r × angular velocity ω And force F × Radius r = torque

it is concluded that power P = torque × angular velocity ω So the power of the engine can be calculated from the torque and speed

the unit of angular velocity is radian / s, which is one in radian system π Represents 180 degrees

definition: φ------- The relative rotation angle between sections

γ------- Shear strain

τ-------- Shear stress

t --- torque

R ------ radius

L -------- material length

torque is a special kind of torque that makes an object rotate. Engine torque refers to the engine torque output from the crankshaft end. When the power is fixed, it is inversely proportional to the engine speed. The faster the speed is, the smaller the torque is, and vice versa. It reflects the load capacity of the vehicle in a certain range. The external torque is called torque or external force couple moment, and the internal torque or internal force couple moment