In gear transmission, what are the pros and cons of the same diameter, more teeth and fewer teeth?

Gearing. than the same, the denser the number of teeth", the coincidence of the gear transmission will be improved (the increase is not large, the effect is not obvious); The effect on reducing wear and tear will not be obvious; Because the gear ratio is the same, the torque of the driving wheel remains the same (it will not be reduced) despite the increase in the number of teeth.

When the center distance and the transmission ratio remain unchanged, the number of teeth is appropriately increased, and the modulus is appropriately reduced, first of all, the material is saved, and the second is to increase the degree of coincidence, and the increase of the degree of overlap will naturally reduce the wear of the teeth. However, it is easy to weaken the bending strength of the tooth root, so it should be reasonable.

There are no pros and cons for a case-by-case analysis.

The number of teeth is small, the gear modulus is large, the force that can be transmitted is large, the smoothness of transmission is low, and the noise is also large.

The number of teeth is large, the gear modulus is small, the force that can be transmitted is small, the stability of transmission is good, and the noise is small.

A little more off-topic.

Generally, when selecting gears, first select the modulus of the gears according to the size of the transmission force, and then add a little after meeting the requirements. Then select the number of teeth according to the needs of the transmission speed ratio. In general, the above requirements can be met, the modulus is as small as possible, and the number of teeth is as small as possible.

The machine designed in this way is small in size and less in cost.

Personally, I think that there is no benefit to more, the less the better, the more the reaction force, the more inconvenient the transmission power.

Instead, it is better to use a rod that connects two gears to transmit power.

If you have different diameters, you can accelerate depending on the power conditions and output needs, but it makes no sense to list many gears of the same diameter together.

You can't simply talk about the pros and cons in itself! In general, the number of teeth is large, the modulus is small, the transmission is stable and the noise is small, but the bending strength is poor. If the number of teeth is less, the modulus will be large, the bending strength is very strong, but the noise is some, and the transmission is not very smooth, it depends on your needs.

And the cost will also change somewhat.

1. The transmission ratio of gear transmission is large.

Disadvantages: The size design of the large gear will be very large, the gearbox will also become large, and the gear is not easy to process and assemble.

Advantages: The transmission with large gear ratio can be self-locking, such as worm and worm gear transmission; The size difference with the low-speed large gear is reduced, which is conducive to the simultaneous oil bath lubrication of the gear at all levels.

2. The transmission ratio of gear transmission is small.

Disadvantages: If the transmission ratio is too small, the deceleration efficiency is low.

Advantages: The low-speed gear directly affects the size and weight of the reducer, and reduces the low-speed transmission ratio, that is, the size and weight of the low-speed gear and the body that contains it are reduced; It reduces the circumferential speed of the high-speed stage and the subsequent stages of gears, which is conducive to reducing noise and vibration and improving the smoothness of transmission.

The relationship between the linear speed of the gear and the speed of the gear is proportional. That is, the linear speed, rotational speed, and perimeter.

The linear velocity of the gear generally refers to the linear velocity of the indexing circle. Linear velocity formula: v d n (meter seconds).

d: diameter of the indexing circle; n: rotational speed.

Linear velocity describes the speed and direction of the motion of a particle as a curvilinear motion. The immediate velocity of the points on the object in a curvilinear motion is in the tangential direction along the orbit of motion.

If the number of teeth of gear 1 is: z1, the speed is: n1, the number of teeth of gear 2 is: z2, and the speed is: n2, then the relationship between the speed of the two meshing gears and the number of teeth is: n1 n2=z2 z1

Because the circumferential velocity (linear velocity) of the two wheels is equal, the gear speed is inversely proportional to the number of teeth.

Can you make a simple analogy?

In a pair of gear transmission sheds, if the number of teeth is to be reduced when the center distance has been fixed, the modulus of the gear (the ratio of the tooth pitch to the number of teeth) will be reduced, so that the tooth surface strength and the tooth root strength are improved. But theyThe ways to get improved are different.

Reducing the number of teeth will reduce the modulus of the gear, and the strength of the tooth surface will be proportional to the modulus, so reducing the number of teeth will improve the strength of the tooth surface. The strength of the tooth root is related to the cross-sectional area of the tooth root of the gear, and the distance between each tooth and the center of the gear will increase by reducing the number of teeth, so the cross-sectional area of the tooth root will increase, thereby improving the root strength.

In conclusion, reducing the number of teeth can improve the tooth surface strength and root strength when the center distance is fixed, but they are improved in different ways.

The more teeth of two gears meshed, the slower the rotational speed.

In other words, the meshing gears have a slow speed with a large number of teeth, and a fast speed with a few teeth.

The formula of the transmission ratio: i=z2 z1, where: i=transmission ratio.

z1 = number of driving gear teeth.

z2 = number of driven teeth.

It is easy to see that if the number of driving gear teeth is constant, the more driven gear teeth there are, the larger the transmission ratio. So why is the larger the gear ratio, the greater the torque of the driven wheel? We use our work and strength to explain this problem.

We know that when the power is certain, mechanical work and output are a pair of contradictions, the transmission ratio is the gear "small belt large", "small belt large", the larger the driven wheel, the larger its power arm, the larger the power arm, the larger the power arm, which has been learned in the principle of leverage. At this time, the pinion may have to turn several turns of the big gear to make one turn, which means that it can save effort, but it is laborious. If the reverse transmission ratio is small, the "big belt small" large gear turns once.

The pinion may have to be turned several times, it is laborious, but it saves work, which is called conservation of energy.

Why isn't the torque the maximum when the engine is at the maximum? Let's look at the equation for the relationship between power, velocity, and force: p=f

where: p = power.

f = force = velocity.

In this formula, it is not difficult to see that speed and output are a pair of contradictions, when the power is constant, the faster the speed then the output will be smaller, you want to output a lot but only a small speed. When the car climbs, you should put your gear below 3rd gear, otherwise it is easy to stall. This is also an example of conservation of energy.

The immortality of matter and the conservation of energy are one of the key points of physics in our junior high school level, and it runs through every case.

Gear transmission is the meshing and "contact" of two gears, if the transmission is long-distance, the diameter of the gear will be very large and bulky, therefore, the gear is not suitable for transmission over a long distance.

Belt drive, chain drive, suitable for long-distance transmission, they have a common feature, that is, there is a flexible transmission between two wheels (pulley or sprocket) - belt or chain. This makes the pulleys and sprockets not have to be very large and bulky.

The machine tool motor uses a belt instead of a gear because the belt slips with overload, which is the function of overload protection, while the gear transmission does not have the function of overload protection.

Hello, gear transmission is a meshing transmission, mainly to bear high-speed and heavy-load occasions, etc., when the gear driving wheel rotates, there should be a corresponding gear meshing transmission movement, such as the transmission distance is not enough to increase the gear movement, which increases the cost, and increases the occurrence of the failure rate, the gear processing cost is high, and it is easy to be unsuitable for long-distance transmission.