|Asia Helical Gearbox, High Performance Gearboxes Producer|
|GUIDE TO SELECTION OF GEARBOXES|
basic factors to consider in choosing a gearbox are the following:
SPEEDS n1; n2
|N.B. the values of HP1 and KW1 must be taken from the tables where input speed (n1) is indicated to be 1400 RPM.|
|POWER KW1 ; HP1|
|The power indicated in the catalogue refers to
the input of the gearbox.
The output power is calculated as follows:
|OUTPUT TORQUE M2|
|The values of M2 indicated in the
catalogue are true because for their calculation we have considered the
These values must be equal higher than the torque necessary to operate the machine they are selected for.
|SERVICE FACTOR s.f.|
Since the gearboxes are often subjected to variable loads, it is better
to choose the group with an adequate coefficient (service factor).
The table below indicates the service factors to consider when you choose the gearboxes.
|It is a characteristic of the gearbox and identifies it self in the formula:|
|In the helical gearboxes the ratios indicated as a whole number are generally rounded. To get the exact values, please revert our technical department.|
|You can calculate: or|
|The figures specified in the catalogue.
Conditions like temperature, type of lubricant, speed, gear characteristics, etc., subject the gearbox to certain variables; therefore for the calculation of torque M2 indicated in the catalogue the efficiency of the groups after running- in has been considered.
The graph below indicates the approx. value of the efficiency pointing out the difference between the gearboxes with 1,2, 3 reductions and the worm- gearboxes.
For the correct selection of gearbox it is necessary to have further information like:
|CHOICE OF THE GEARBOXES|
|When you have all the necessary
information you can choose the gearboxes in the relative tables of GEARBOXES
CHARACTERISTICS where the values Kw1; HP1; M2; are calculated
with s.f. = 1
If you know the torque M or the power KW (or HP) required, you will find the gearbox with:
is the efficiency of the gearbox itself. Generally you should avoid the
installation of motors with power higher than that required because it can
subject the gearbox (and also the connecting gears) to shocks and stresses,
which can jeopardize its life span, since the dimensions have been made
according to the power absorbed by the machine and not according to the
power installed. Besides it is also more expensive both for energy consumption
and for the electrical system.
You can use higher powers only if it is certain that they will never be required for particular operating conditions (ex.: with an high number of connections).
The gearboxes admit momentary overloads like 100% of the nominal torque, obviously with a limited number of connections.
If you have higher values, you must choose the gearbox with a torque M equal to 50 % of the overloads value, multiplied by the service coefficient concerning the kind of application.
|CHOICE OF THE GEARED MOTORS|
When s.f. = 1, the selection of the geared motors can be made directly
from the relative tables of GEARED MOTORS CHARATERISTICS
|RADIAL AND AXIAL LOADS|
|It is necessary to check that the eventual radial and/or axial loads are not higher than the values indicated in the relative tables.(Expressed in daN)|
|It is important to indicate the mounting position so that the gearbox can be properly lubricated. in the chapters concerning the different types of gearboxes we have indicated when it is not necessary to specify the mountings position.|
|Before use, the gearboxes with oil lubrication
must be filled with the right quantity of oil by the customer. For this
purpose the gearboxes are supplied with level, drain and breather plugs.
Please specify the proposed mounting position to facilitate correct positioning
of the plugs.
Mineral lubricants can be used with an ambient temperature between 0
°C and +30 °C.
For the installation of the gearbox the following guidelines should be observed:
When the gearboxes are lubricated with synthetic grease no further maintenance is required when the gearboxes are lubricated with mineral oil the following procedure is recommended:
If the gearbox is lubricated with synthetic oil you have , to change
the oil after 8000 working hours. When the gearbox is standing for a long
time in a very damp environment it is better to fill it completely with
oil; naturally the lubricant level must be restored when the gearbox is
put back into operation