JPH0136333B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotating electrical machine to which a magnetic wedge is mounted, and more particularly to a method for mounting a magnetic wedge.

Slots in rotating electric machines house field coils in the stator and conductors for extracting electrical and mechanical energy in the rotor, and are essential to the structure of the rotating electric machine. However, the problems caused by the slots to the characteristics of the rotating electric machine include the generation of stator and rotor groove harmonics, an increase in magnetic current due to a decrease in magnetic flux, and an increase in the temperature of the coil. In order to reduce these problems, half-closed slots are used in low-voltage rotating electric machines.
An organic film or thin plate is used as a wedge to hold the coil. On the other hand, in stators for high-voltage, medium- and large-sized rotating electric machines, when the slots are left open to store the field coils, magnetic wedges are used instead of non-magnetic wedges to improve the characteristics. There are two methods: one in which the slot is mechanically driven in, and the other in which a putty-like material is filled into the slot and hardened, both of which are highly effective in improving characteristics.

In recent years, magnetic wedges have been proposed for small rotating electrical machines using the above-mentioned semi-closed slots in order to reduce temperature rise, improve motor characteristics such as increase efficiency, or to reduce the size of the machines, but they have not been put to practical use. The reason for this is that the stator slot of a small rotating electric machine that uses semi-closed slots has an extremely small space for storing the wedge, and even if the wedge is replaced with a magnetic wedge made of organic film made of molded or cast material, it is extremely difficult due to the material and manufacturing considerations. It is difficult and the function cannot be satisfied, and the putty-like material has poor workability. Both do not have a wedge groove like an open slot, and because they have poor adhesion, the wedges tend to move and fall off from their predetermined positions due to vibrations or thermal cycles during assembly, starting and stopping of the rotating electric machine. The drawback was that the magnetic resistance increased, making it impossible to improve the characteristics as designed.

The present invention has been made in view of the above-mentioned drawbacks, and provides a high-performance rotating electric machine that can maintain reliability over a long period of time by fixing a magnetic wedge in a predetermined position in a semi-closed slot, without falling off due to vibration. The purpose is to

That is, the present invention provides a method for easily and reliably attaching a magnetic wedge to a slot opening of a stator or rotor equipped with a conductor, thereby providing a highly reliable, high-performance rotating electric machine. It is something.

The present invention will be described below with reference to one embodiment. First, as shown in FIG. 1, a magnetic wedge that can be inserted into a predetermined slot opening is cut out of a composite formed by laminating a foamed resin layer 1 containing magnetic powder dispersed therein and a foamed resin 2 containing no magnetic material. I'll keep it. On the other hand, as shown in Fig. 2, the opening 5 of the semi-closed slot 4 is fitted with a field coil for the stator and a conductor 3 for extracting electrical and mechanical energy for the rotor. The magnetic wedge 6 is inserted. In Fig. 2, 7 is the iron core, 8 is the slot insulator, and 9 is the iron core.
indicates an insulating film. After the magnetic wedge 6 is inserted into the opening 5 of the semi-closed slot 4 of the iron core 7 as described above, it is heated to a temperature of, for example, 100 to 180°C. By this heating, the foamable resin layers 1 and 2 forming the magnetic wedge 6 are both foamed, and while filling the slot opening 5, the insulating film 9 is fixed and sealed. Figure 3 shows the state in which the magnetic wedge 6 is inserted and the slot opening 5 is fixed and sealed, where 1a is a foamed resin layer containing magnetic material, and 2a is a foamed resin layer that does not contain magnetic powder. show.

In the method of the present invention, the foamable resin that forms the main body of the foamed magnetic wedge is, for example, an epoxy resin containing dispersed organic blowing agents such as nitroso type, sulfone hydraside type, or azo type, polyester resin, or unsaturated resin such as 1,2 polybutadiene. These include resins, polyurethanes, etc. (including, of course, curing agents and curing catalysts). The magnetic powder dispersed in the foamable resin to form one of the foamable resin layers 1a is, for example, iron powder, and its content is preferably about 60 to 95% by weight.
Furthermore, the other foamable resin layer 2a may be composed only of the above-mentioned foamable resin, but if necessary, a filler other than magnetic powder, such as an inorganic oxide such as SiO ₂ , may be appropriately blended.

However, the foamable resin layer containing magnetic powder and the foamable resin layer 2 not containing magnetic powder, which form the magnetic wedge 6, may be composed of the same type of foamable resin.
In order to sufficiently fill the attached conductor 3 side, the foamable resin layer 2 that does not contain magnetic powder and is inserted and inserted on the conductor 3 side is selected to have a high foaming rate. In addition, in consideration of the final strength and fixing strength of the magnetic wedge 6, it is preferable to use a thermosetting resin as the foamable resin, and furthermore, from the viewpoint of ease of handling during insertion, an appropriate foaming resin should be used before the foaming process. 1,2 polybutadiene having elasticity is preferred.

As described above, according to the present invention, a composite consisting of the foamed resin layer 1 containing magnetic powder dispersed therein and the foamed resin layer 2 containing no magnetic powder is used as the material of the magnetic wedge, and does not contain magnetic powder. The foamed resin layer 6 is inserted into the slot 4 with the conductor 7 side mounted thereon. In this state, in order to heat and foam the magnetic wedge material, the opening of the slot is integrally sealed with a foam containing magnetic powder to provide the required magnetic permeability function, and the gap on the conductor 7 side in the slot is also magnetic. Filled with powder-free foam. However, since the magnetic wedge body made of the above-mentioned foam is strongly immobilized by the enlarged foam in the slot, it does not come off even during rotation (during startup) and is able to fully perform the required function as a wedge. Demonstrate and maintain. In particular, by selecting a foamable resin layer 1 containing magnetic powder with a low foaming rate and a foaming resin layer 2 that does not contain magnetic powder with a high foaming rate, the filling in the slot can be made more sufficient. As a result, the slot opening forms a magnetic wedge exhibiting a more stable magnetic permeability.

If only a foamable resin layer containing magnetic powder is used, after foaming, large voids will be generated inside the foam, and the expansion ratio will be large, resulting in unstable magnetic permeability, making it impossible to obtain the desired magnetic permeability. Furthermore, if the foaming ratio is made small, there is a risk that the wedge will fall off during startup or due to impact, which has a drawback in reliability.

The wedge having a two-layer structure according to the present invention can suppress the generation of large voids by reducing the foaming ratio of the foamable resin layer containing magnetic powder, and can also obtain stable magnetic permeability because the foaming ratio is small. Furthermore, since the foamed layer that does not contain magnetic powder has a large foaming ratio, it can fill the void and prevent the magnetic wedge from falling off.

As described above, according to the method of the present invention, since the magnetic wedge can be easily and reliably fixed at a predetermined position within the slot, it is also possible to reduce iron loss due to harmonic magnetic flux.
Further, the magnetic wedge does not move or fall off even when the machine is stopped due to vibrations.

Therefore, in combination with exhibiting the above-mentioned stable magnetic permeability, characteristics as designed can be obtained and reliability can be imparted. Thus, the method of the present invention can be said to be a method for inserting and attaching a magnetic wedge to a rotating electrical machine, which brings many practical advantages in terms of ease of operation.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing an example of the structure of a magnetic wedge material used in the method of the present invention, and FIGS. 2 and 3 are cross-sectional views showing a slot portion for explaining an embodiment of the method of the present invention. 1... Foamable resin layer containing magnetic powder, 1a...
Foam containing magnetic powder, 2... Foamed resin layer containing no magnetic powder, 2a... Foam containing no magnetic powder, 3... Conductor, 4... Half-closed slot, 5...
Slot opening, 6...magnetic wedge, 7...iron core.

Claims (1)

[Scope of Claims] 1 A foamable resin layer containing magnetic powder is provided at the slot opening of the rotor or stator to which the conductor is attached, and a foaming resin having a foaming rate higher than the foaming rate of the foaming resin constituting the foamable resin is provided. A magnetic wedge made of a foamed resin layer that does not contain magnetic powder made of resin is inserted so that the foamed resin layer that does not contain magnetic powder is on the conductor side installed in the slot, and then both the A method for attaching a magnetic wedge to a rotating electrical machine, characterized by sealing a slot opening by heating and foaming a foamable resin layer. 2. A method for attaching a magnetic wedge to a rotating electric machine as set forth in claim 1, wherein the foamable resin is a thermosetting resin.