How to calculate the moment of friction
Publish: 2021-05-12 10:56:19
1. A store of express can sell all kinds of procts under a big category
Global Express is Alibaba's online trading platform for the global market, which is known as the international version of "Taobao" by the majority of sellers
just like Taobao, you can edit your baby into online information and publish it overseas through the express platform. Similar to the domestic delivery process, the baby is transported to the buyer through international express delivery. In this way, it is easy to enter into transactions with buyers from more than 220 countries and regions and earn US dollars. However, in order to protect domestic e-commerce and restrict or prohibit cross-border online shopping, Russia and Argentina have implemented corresponding policies.
Global Express is Alibaba's online trading platform for the global market, which is known as the international version of "Taobao" by the majority of sellers
just like Taobao, you can edit your baby into online information and publish it overseas through the express platform. Similar to the domestic delivery process, the baby is transported to the buyer through international express delivery. In this way, it is easy to enter into transactions with buyers from more than 220 countries and regions and earn US dollars. However, in order to protect domestic e-commerce and restrict or prohibit cross-border online shopping, Russia and Argentina have implemented corresponding policies.
2. If the friction force has a definite force application point, the moment is equal to the force point multiplied by the position vector, or the force multiplied by the arm of force
if the friction force occurs on a line, the moment at each point needs to be integrated. If it occurs on a surface, it needs to be quadratic integrated. Generally, it is decomposed into lines, such as a rotating disk, and it is differentiated into rings, The moment of each ring is solved first and then integrated
if the friction force occurs on a line, the moment at each point needs to be integrated. If it occurs on a surface, it needs to be quadratic integrated. Generally, it is decomposed into lines, such as a rotating disk, and it is differentiated into rings, The moment of each ring is solved first and then integrated
3. If the friction force has a definite force application point, the moment is equal to the force point multiplied by the position vector, or the force multiplied by the arm of force
if the friction force occurs on a line, the moment at each point needs to be integrated. If it occurs on a surface, it needs to be quadratic integrated. Generally, it is decomposed into lines, such as a rotating disk, and it is differentiated into rings, The moment of each ring is solved first and then integrated
if the friction force occurs on a line, the moment at each point needs to be integrated. If it occurs on a surface, it needs to be quadratic integrated. Generally, it is decomposed into lines, such as a rotating disk, and it is differentiated into rings, The moment of each ring is solved first and then integrated
4. One of the methods to calculate the friction torque of rolling bearings is to divide the friction torque into independent parts, including the torque M0 which is not affected by the load and the torque M1 which depends on the load, and then add the two together to get m = M0 + M1, which is still used today. However, if not only the load factor is considered, but also the root cause of friction is analyzed in detail, a more accurate calculation method can be given. In fact, M0 refers to the friction other than coincidence. If the component of hydrodynamic force in rolling friction is added, it also becomes the part related to load. In order to calculate the friction torque of rolling bearings more accurately, four different causes of friction must be considered, M = MRR + MSL + mseal + mdrag, where M = total friction torque, NMM MRR = rolling friction torque, NMM MSL = sliding friction torque, NMM mseal = friction torque of seals, NMM mdrag = friction torque caused by drag damage, vortex and splash, etc, NMM is a new method to determine each cause of friction occurring in bearings and to combine these factors. In addition, the total friction torque can be calculated by adding the friction caused by seals and other additional reasons. Because each contact part (raceway and rib) is considered separately in this model, it is convenient to change the design and improve the surface quality, and can reflect the improvement in SKF Bearing design. This model is also easier to update.
5. Change LZ title, R and R to R1, R2 (R1 & gt; R2)
the ring is pressed against the wall by the force F and rotates at a constant speed, and the friction coefficient is u,
then there is, the pressure on the ring per unit area (i.e. pressure) is p = f / Π (R1 ^ 2-r2 ^ 2)
take a infinitesimal annular belt at the distance r from the center of the circle, and its radial width is Dr, The area of the area is DS = 2928;\\\\\\\\\\\\\\> 0 The result is as follows:
MF = ∫ DMF = [2uF / 3 (R1 ^ 2-r2 ^ 2)] * (R1 ^ 3 - R2 ^ 3) = 2uF (R1 ^ 2 + r1r2 + R2 ^ 2) / 3 (R1 + R2)
the final conversion parameter is
MF = 2uF (R ^ 2 + R + R ^ 2) / 3 (R + R)
the ring is pressed against the wall by the force F and rotates at a constant speed, and the friction coefficient is u,
then there is, the pressure on the ring per unit area (i.e. pressure) is p = f / Π (R1 ^ 2-r2 ^ 2)
take a infinitesimal annular belt at the distance r from the center of the circle, and its radial width is Dr, The area of the area is DS = 2928;\\\\\\\\\\\\\\> 0 The result is as follows:
MF = ∫ DMF = [2uF / 3 (R1 ^ 2-r2 ^ 2)] * (R1 ^ 3 - R2 ^ 3) = 2uF (R1 ^ 2 + r1r2 + R2 ^ 2) / 3 (R1 + R2)
the final conversion parameter is
MF = 2uF (R ^ 2 + R + R ^ 2) / 3 (R + R)
6. Use the formula: T = 2 π FPZ (R ^ 3-R ^ 3) / 3
where f is the static friction coefficient between the friction surfaces. In general, for powder metallurgy materials, the copper base is 0.25-0.35, and the iron base is 0.35-0.5; P is the unit pressure on the friction surface, 0.35-0.5 MPa for general powder metallurgy materials (copper base and iron base); Z is the number of friction surfaces, 2 for single disc and 4 for double disc; R is the outer diameter and R is the inner diameter
the formula can also be changed to t= π Fpzd ^ 3 (1-C ^ 3) / 12, D is the outer diameter, C is the ratio of inner diameter to outer diameter, generally between 0.53-0.7, C can not be too large, if C is too large, it means that the difference between inner diameter and outer diameter is large, so in the process of clutch contact, e to the large linear velocity difference near the inner diameter and outer diameter, the wear difference is too large, so that the clutch disc is uneven after a long time, or the unevenness is too large. If the clutch is designed, the reserve coefficient, unit torque, sliding work per unit area and maximum linear speed should also be considered. There is a limit, which can be checked by formula. I won't repeat them one by one here. I hope it will be helpful to your project. If you have something I don't understand, please contact me.
where f is the static friction coefficient between the friction surfaces. In general, for powder metallurgy materials, the copper base is 0.25-0.35, and the iron base is 0.35-0.5; P is the unit pressure on the friction surface, 0.35-0.5 MPa for general powder metallurgy materials (copper base and iron base); Z is the number of friction surfaces, 2 for single disc and 4 for double disc; R is the outer diameter and R is the inner diameter
the formula can also be changed to t= π Fpzd ^ 3 (1-C ^ 3) / 12, D is the outer diameter, C is the ratio of inner diameter to outer diameter, generally between 0.53-0.7, C can not be too large, if C is too large, it means that the difference between inner diameter and outer diameter is large, so in the process of clutch contact, e to the large linear velocity difference near the inner diameter and outer diameter, the wear difference is too large, so that the clutch disc is uneven after a long time, or the unevenness is too large. If the clutch is designed, the reserve coefficient, unit torque, sliding work per unit area and maximum linear speed should also be considered. There is a limit, which can be checked by formula. I won't repeat them one by one here. I hope it will be helpful to your project. If you have something I don't understand, please contact me.
7. According to the law of conservation of momentum, the internal force of the system does not work on the system; On the other hand, the direction of angular momentum at the output end of the engine is determined by the right-hand screw rule. When the propeller turns clockwise, the total angular momentum should be ensured
8. The integral differential element is
DM = R × df=r ×μ× dN=r μ×ρ×( two π r × dr)=2 πρμ R ^ 2DR
in brackets is the area of the ring with radius R and width Dr, ρ Is the area density of gravity
ρ= mg/( π R ^ 2)
will 2 πρμ The integral of R ^ 2DR over 0 to R is obtained
DM = R × df=r ×μ× dN=r μ×ρ×( two π r × dr)=2 πρμ R ^ 2DR
in brackets is the area of the ring with radius R and width Dr, ρ Is the area density of gravity
ρ= mg/( π R ^ 2)
will 2 πρμ The integral of R ^ 2DR over 0 to R is obtained
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