CLIAMS:CLAIMS:

Our claims of the invention are
1) A method of assembling rotor which does not require glue or requires very little glue
2) A method which does not require any special machine for gluing the magnets and rotor core
3) A method whose rotor lamination and magnet shape is designed in such a way that when they are assemblled the magnets are held firmly in position without making any side or latteral movement while in operation.
4) The whole process is completed in much less time, reducing the process time and process cost considerably
5) The method reduces the total material cost of the product in addition to the process cost.
,TagSPECI:OUR INVENTION:
The proposed invention uses a stacked sloted rotor core as shown in the figure 1.
Figure 1
The rotor stack is formed from a riveted bunch of rotor laminations of high permeability steel material. The rotor has slots matching to the shape of the permanent magnet. The rotor stack is pressed into the rotor cover as shown in figure 2. This forms a proper bonding between the cover and the rotor core. The pressing of rotor core to bottom cover takes less than 15seconds, compared to gluing of 4 segments which takes 240 seconds and a curing time of approximately 24 hours.

Figure 2.
The magnets are cast to suitable tolerance and shape. After magnetizing the magnets to required strength the magnet can be easily slid into the slot provided on the rotor core. The magnet shape and its corresponding slot design is done in such a way that when the magnet is slid inside the slot, completely, arresting the lateral movement of the magnet firmly. Further the magnetic attraction to the magnetic material also enhances the arresting of the lateral movement of the magnet. The whole process of insertion of the magnet into its slots takes < 60 seconds when compared to the present 180 seconds for the magnets and a curing time of 24hours. The fully assembled rotor is shown in the figure 3 below. The figure 4 shows typical shape of a magnet.

Figure 3.

Figure 4

While the side movements are arrested, the magnet can, still, have upward movement if the tolerances are not properly adhered to. This can be be arrested by many methods. One of the methods is by putting few drops of glue along the mating surface of the magnet with the rotor core. This entire process does not need any fully aautomated or semi-automated machine. An exploded view of the assembly is shown in the figure 5.

Figure 5.

Thus the whole assembly of the rotor gives following advantages
1) Reduces the rotor assembly time approximately by 6 times when compared to the earlier method.
2) The curing time of the rotor is zero when compared to 24 hours in the earlier method
3) Other than a “press” to press the rotor stack into bottom cover no machine is required to complete the rotor assembly
4) No of magnets required, reduces to 50%. Overall magnet cost is reduced because of reduction of magnet volume and weight.
5) The total material cost + process cost of the rotor reduces considerably.

The performance of the fan does not change with this method of magnet assembly and rotor manufacture . Thus the new invention has immense benefits.