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Pulleys, belts and gears - Contenido educativo

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Subido el 28 de enero de 2020 por Isabel L.

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Well, now we are going to explain pulleys, belts and gears. 00:00:00
The transmission of movement is really important to have a good work to all of the machines. 00:00:07
So mechanical system always consists in different pulleys, belts and gears 00:00:18
which transmits the movement from one part to another. 00:00:28
This is a type of mechanism. 00:00:33
Well, if you have two objects with rotation, 00:00:37
you can discompose the speed in a point that both objects have in common, the touch point. 00:00:43
And the conclusion of this is that if you want to have a good rotation without any slide, 00:00:57
you need that the two objects must be cylinders, otherwise the rotation is not good 00:01:07
good and the transmission of the movement is not constant which sometimes can be or could be 00:01:20
a problem in some machines. So we can conclude that the two objects that are in touch must be 00:01:28
the cylinders and the transmission ratio can be expressed in this way with taking into 00:01:39
consideration the diameter of the ratio of the cylinders which are in touch. 00:01:56
Well the touch can be in different ways as you can see here and it's also important to 00:02:06
take into consideration when you have to choose a particular mechanism to particular application. 00:02:15
So this is the most important thing, the transmission ratio, which is the ratio between the rotation 00:02:26
Well, so depending the dimension of the wheels which are in touch, the ratio of rotation 00:02:35
speed can be different also. If the driven wheel is smaller than driven, the rotation 00:02:56
speed in the driven is higher, is bigger than in the driven, so this type of mechanism is 00:03:20
usually called multiplication mechanism. 00:03:32
The opposite case is inverse, so the mechanism in this time is usually called reduction mechanism. 00:03:39
It's important that you take into consideration that the sense of rotation in the driven wheel 00:03:51
is opposite to the driver's. 00:04:02
Well the energy, the energy is always the same value, well you can have some irreversibilities 00:04:09
but in each way the power is always the same. So what happened? Well, the conclusion is that if you 00:04:21
have different forces that you want to move, it's opposite, as you can see in this slide. 00:04:34
well if you want to guarantee in the transmission of the movement because you 00:04:48
have so many power to move or the speed is too high instead of wheels you can 00:05:02
you must use gears a gear is a wheel in which you have you have is a wheel with 00:05:12
teeth in the super files so in this case the teeth must be the teeth guarantee 00:05:21
the movement from the driver to the driven on is the way they can you have 00:05:32
difference important thing in a teeth, but not only the number of the teeth in 00:05:46
the surface and also the relationship between the number and its size, 00:05:53
the diameter. This is usually called modulum. If you want that two teeth work 00:06:04
properly both driver and driven must have the same module and in this way 00:06:13
if you repeat the relationship taking this into consideration 00:06:23
the transmission ratio can be expressed using the number of teeth 00:06:31
you have in each gear as you can see in this slide. Sometimes if the 00:06:38
distance are very very long you can transmit the movement using belts or 00:06:47
chains. In this case the sense of the rotation is the same but you can change 00:06:54
the sense of rotation changing also the belts of change and what you have in this slide you 00:07:03
can have a reverse direction cross the belt for example but if you don't cross the belt 00:07:14
Well, the rotation is in the same sense in the driver and in the driver wheel. 00:07:23
And the relation, the transmission ratio is the same, has the same stress. 00:07:33
Well this is something relating to the stress that the belts must have because obviously 00:07:42
the transmission is important and they have a little bit of stress in the in the belts 00:07:49
that is not so important it's just only something to to know it 00:07:58
Idioma/s:
en
Autor/es:
Isabel Lafuente Reboredo
Subido por:
Isabel L.
Licencia:
Reconocimiento - No comercial
Visualizaciones:
130
Fecha:
28 de enero de 2020 - 20:19
Visibilidad:
Público
Centro:
IES JOSÉ GARCÍA NIETO
Duración:
08′ 06″
Relación de aspecto:
4:3 Hasta 2009 fue el estándar utilizado en la televisión PAL; muchas pantallas de ordenador y televisores usan este estándar, erróneamente llamado cuadrado, cuando en la realidad es rectangular o wide.
Resolución:
1440x1080 píxeles
Tamaño:
75.15 MBytes

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