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A gear train is a succession of gear wheels meshed together in such a way that the rotation of one causes the rotation of the others. The transmission of kinetic energy from an engine of any type to a user element is based on this simple mechanism, which is therefore utilised in several machineries.
In this video, we are firstly going to point out the principles of gear trains. Consequently, we will explore how they apply to Reduction Drives and how these ones are related to gearmotors.
Being committed for over 10 years in the industrial supplies sector, Jaes currently offers every type of Reduction Drive and Gearmotor made by whichever major manufacturer. You can easily find these items in its catalogue.
Gear trains are a succession of gear wheels meshed together, in which the rotation of one wheel causes the rotation of the others.
Let’s take as an example the simplest possible model, which are Gear trains with two gears, one of 0.3 meters radius with 30 tines and one of 0.6 meters radius with 60 tines. The number of tines in a gear is proportional to the diameter of its pitch circle; the primitive circumferences of a pair of gear wheels are therefore tangent to each other and form a line of contact during meshing.
The gear transmitting the motion is called drive gear, while the gear receiving the motion is called driven gear.
Now let’s assume that the smaller gear is plugged to an electric motor (therefore being a driving force). As you can see it rotates clockwise, and the larger gear connected to it will take on a counter-clockwise rotation.
It can also be noted that the speed of rotation of the driven gear is different. It is slower, not so much due to the size of the gears, rather because of the ratio between their diameters and, as a consequence, among the quantity of tines. This particular ratio is called ‘gear ratio’.
Calculating it is very simple: you should just take the diameter of the driven gear and divide it by that of the drive gear. You can also perform the same calculation with the radiuses or the number of tines of the gears. In this case, the gear ratio is "2" that is 2 to 1 (2: 1), which means that the drive gear has to complete a lap twice to allow the driven gear to perform a complete revolution. For this reason, we could say that we are dealing with an example of a Reduction Drive.
Indeed, the rotation speed of the two shafts is inversely proportional to the number of tines of the two gears. In point of fact, if we want to derive the gear ratio from the pace, we must invert the mathematical ratio. That is, we must consider the speed of the drive gear and divide it by that of the driven gear.
Therefore, if the gear ratio is greater than 1, it can be defined as ‘Reductant’ and, consequently, the whole gear would be called ‘Reduction Drive’.
Moreover, in case the driven gear rotates at the same speed as the drive gear (therefore proceeding at a ratio equal to 1), the gear ratio is defined as ‘Impartial’.
To conclude, if the gear ratio is smaller than 1, the whole mechanism is defined as a ‘Multiplying Drive’ with a ‘Multiplying’ ratio.
In mechanics, the use of Reduction Drives is much more frequent than the use of Multiplying Drives, since motors are built to maintain a high rotation pace.
Now let’s try to calculate the speed of the driven gear, knowing that the drive gear has a speed of 50 revolutions per second given by the electric motor; through simple maths we can then perform this equation:
Speed of the drive gear x number of the Drive gear tines = speed of the driven gear x number of the driven gear tines
As a result, we have that the pace of the driven gear has been reduced to 25 revolutions per second.
In this video, we are firstly going to point out the principles of gear trains. Consequently, we will explore how they apply to Reduction Drives and how these ones are related to gearmotors.
Being committed for over 10 years in the industrial supplies sector, Jaes currently offers every type of Reduction Drive and Gearmotor made by whichever major manufacturer. You can easily find these items in its catalogue.
Gear trains are a succession of gear wheels meshed together, in which the rotation of one wheel causes the rotation of the others.
Let’s take as an example the simplest possible model, which are Gear trains with two gears, one of 0.3 meters radius with 30 tines and one of 0.6 meters radius with 60 tines. The number of tines in a gear is proportional to the diameter of its pitch circle; the primitive circumferences of a pair of gear wheels are therefore tangent to each other and form a line of contact during meshing.
The gear transmitting the motion is called drive gear, while the gear receiving the motion is called driven gear.
Now let’s assume that the smaller gear is plugged to an electric motor (therefore being a driving force). As you can see it rotates clockwise, and the larger gear connected to it will take on a counter-clockwise rotation.
It can also be noted that the speed of rotation of the driven gear is different. It is slower, not so much due to the size of the gears, rather because of the ratio between their diameters and, as a consequence, among the quantity of tines. This particular ratio is called ‘gear ratio’.
Calculating it is very simple: you should just take the diameter of the driven gear and divide it by that of the drive gear. You can also perform the same calculation with the radiuses or the number of tines of the gears. In this case, the gear ratio is "2" that is 2 to 1 (2: 1), which means that the drive gear has to complete a lap twice to allow the driven gear to perform a complete revolution. For this reason, we could say that we are dealing with an example of a Reduction Drive.
Indeed, the rotation speed of the two shafts is inversely proportional to the number of tines of the two gears. In point of fact, if we want to derive the gear ratio from the pace, we must invert the mathematical ratio. That is, we must consider the speed of the drive gear and divide it by that of the driven gear.
Therefore, if the gear ratio is greater than 1, it can be defined as ‘Reductant’ and, consequently, the whole gear would be called ‘Reduction Drive’.
Moreover, in case the driven gear rotates at the same speed as the drive gear (therefore proceeding at a ratio equal to 1), the gear ratio is defined as ‘Impartial’.
To conclude, if the gear ratio is smaller than 1, the whole mechanism is defined as a ‘Multiplying Drive’ with a ‘Multiplying’ ratio.
In mechanics, the use of Reduction Drives is much more frequent than the use of Multiplying Drives, since motors are built to maintain a high rotation pace.
Now let’s try to calculate the speed of the driven gear, knowing that the drive gear has a speed of 50 revolutions per second given by the electric motor; through simple maths we can then perform this equation:
Speed of the drive gear x number of the Drive gear tines = speed of the driven gear x number of the driven gear tines
As a result, we have that the pace of the driven gear has been reduced to 25 revolutions per second.
However, the true interesting feature of the Reduction Drives is the mechanical advantage they produce. Indeed, although the pace decreases, the torque increases proportionally. In fact, consider an engine performing 50 revolutions per second has a torque of 5 newton meters (5 Nm). With this reductant ratio halved, it would perform 25 revolutions per second and 10 newton meters (10 Nm) of torque at the driven gear.
Basically, halving the ratio, you can do heavier jobs at a slower speed.
For these two benefits, reduction drives are widely used in every field of mechanics, from internal combustion engines to pneumatic and hydraulic ones, and especially when combined with electric motors that have very high rotation speeds.
In fact, gearboxes and electric motors are generally sold in pairs to have compatible characteristics; so much so that compact reducers unified with electric motors called Gearmotors are even designed and produced, reducing overall dimensions and costs.
From a mechanical standpoint, different solutions are adopted for the reduction depending on the needs, let’s have a brief overview of the main ones:
- There are gearboxes with gears that can be cylindrical or conical; with straight or helical tines; and which often have a Double reduction gear configuration, where a second reduction stage is added to the first to have a more compact solution when compared to a two-gear gearbox with the same gear ratio. Moreover, the direction of rotation does not change and the axes of both the drive shaft and the driven shaft are parallel.
They are mainly used in industrial sectors, which require high power and long and intensive work sessions.
- Next up are Worm drives, in which, thanks to its rotating movement, a worm screw moves a worm wheel, whose tines can be straight or helical. Although using only two elements and also considering the small dimensions, they have a high gear ratio. Usually the driven shaft is positioned orthogonally with respect to the input motor shaft.
Furthermore, thanks to their conformation, they can rarely be reversible, i.e. the gear cannot drive the worm screw, which leads to greater safety in certain situations.
- Lastly we will have a look at an epicyclic gear train (also known as a planetary gearset) ; it is composed in such a way that at least one of the gear bearing axles is movable.
The components are four:
The pinion (sun gear) which is usually connected to the crankshaft;
The ring gear, which is often locked to the gearbox casing;
and the planet gears held together by the carrier, which while operating it rotates between the sun gear and the ring gear bringing motion to the driven shaft.
However, this is not always the case. Indeed, based on which element it is fixed on, the epicyclic gearing assumes different types of reduction:
with driving sun gear, fixed ring gear and carrier on the driven shaft, a high gear ratio is obtained;
with driving sun gear, fixed carrier and ring gear on the driven shaft, there is a different gear ratio;
with driving ring gear, fixed sun gear and carrier on the driven shaft, a lower reduction than the previous ones is obtained;
By forming a system of several planet gears one after the other, further and various reductions can be obtained.
Therefore, from the car to the remote-controlled toy car, from the conveyor belt to the precision robot, the applications of gearmotors are several and they play a major role in our everyday life!
If you thought this video was useful for you, please let us know by leaving a like and a comment. You can also share it wherever you want, and don’t forget to subscribe to our channel.
Basically, halving the ratio, you can do heavier jobs at a slower speed.
For these two benefits, reduction drives are widely used in every field of mechanics, from internal combustion engines to pneumatic and hydraulic ones, and especially when combined with electric motors that have very high rotation speeds.
In fact, gearboxes and electric motors are generally sold in pairs to have compatible characteristics; so much so that compact reducers unified with electric motors called Gearmotors are even designed and produced, reducing overall dimensions and costs.
From a mechanical standpoint, different solutions are adopted for the reduction depending on the needs, let’s have a brief overview of the main ones:
- There are gearboxes with gears that can be cylindrical or conical; with straight or helical tines; and which often have a Double reduction gear configuration, where a second reduction stage is added to the first to have a more compact solution when compared to a two-gear gearbox with the same gear ratio. Moreover, the direction of rotation does not change and the axes of both the drive shaft and the driven shaft are parallel.
They are mainly used in industrial sectors, which require high power and long and intensive work sessions.
- Next up are Worm drives, in which, thanks to its rotating movement, a worm screw moves a worm wheel, whose tines can be straight or helical. Although using only two elements and also considering the small dimensions, they have a high gear ratio. Usually the driven shaft is positioned orthogonally with respect to the input motor shaft.
Furthermore, thanks to their conformation, they can rarely be reversible, i.e. the gear cannot drive the worm screw, which leads to greater safety in certain situations.
- Lastly we will have a look at an epicyclic gear train (also known as a planetary gearset) ; it is composed in such a way that at least one of the gear bearing axles is movable.
The components are four:
The pinion (sun gear) which is usually connected to the crankshaft;
The ring gear, which is often locked to the gearbox casing;
and the planet gears held together by the carrier, which while operating it rotates between the sun gear and the ring gear bringing motion to the driven shaft.
However, this is not always the case. Indeed, based on which element it is fixed on, the epicyclic gearing assumes different types of reduction:
with driving sun gear, fixed ring gear and carrier on the driven shaft, a high gear ratio is obtained;
with driving sun gear, fixed carrier and ring gear on the driven shaft, there is a different gear ratio;
with driving ring gear, fixed sun gear and carrier on the driven shaft, a lower reduction than the previous ones is obtained;
By forming a system of several planet gears one after the other, further and various reductions can be obtained.
Therefore, from the car to the remote-controlled toy car, from the conveyor belt to the precision robot, the applications of gearmotors are several and they play a major role in our everyday life!
If you thought this video was useful for you, please let us know by leaving a like and a comment. You can also share it wherever you want, and don’t forget to subscribe to our channel.