JPS58224548A - Manufacture of composite material type rotor - Google Patents

Abstract

PURPOSE:To facilitate the arrangement of magnetic materials by installing a rotor core in a casting mold, and applying a magnetic field radially to a casting space formed between the core and the mold. CONSTITUTION:A rotor core 2 is disposed coaxially in a casting mold 7 which has a cavity including an inner diameter larger than the outer diameter of the core, magnetic materials 5 which are filled in the casting space formed between the core 2 and the mold 7, a radial magnetic field is applied to the space to arrange it, and molten metal of conductive material 4 filled in the casting space is cooled and solidified while holding the radial arrangement of the materials 5. Then, the arrangement of the magnetic materials can be extremely readily and efficiently performed, and yet a conductive energizing sheath may be easily formed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for manufacturing a rotor for an induction motor, and more particularly to a method and apparatus for manufacturing a composite rotor suitable for inverter operation.In general, rotors for induction motors include: Wound rotor, in which slots are formed in the rotor core and compressed so that the rotor windings are housed in the slots, and squirrel-cage rotors, in which slots are similarly formed and squirrel-cage conductors are housed in them. There are three types: rotor rotors, and block rotors in which the rotor core itself functions as a conductor. Among these, squirrel cage rotors are most widely used because they are robust, relatively inexpensive, and have good electrical characteristics.

On the other hand, in recent years, induction machines have been increasingly operated at variable speeds using variable frequency power supplies such as inverters.1 Variable frequency power supplies such as inverters are usually composed of semiconductor circuits, and their output is generally h The result is a distorted wave that includes harmonics.

For this reason, the magnetic flux of an induction motor contains many harmonics, which significantly increases electromagnetic vibration noise and torque pulsation compared to operation using a sine wave power source.This tendency is particularly noticeable in the case of a squirrel cage rotor. Therefore, as a rotor that does not have slots in the rotor core and is suitable for in-bark drive, a current-carrying outer skin made of a composite material of a conductive material and a magnetic material is provided on the outer periphery of the core. This is called a composite rotor1.The structure of this composite rotor is approximately the same as the first one.
and FIG. 2.

That is, this rotor is provided with an iron core 2 formed by laminating disc-shaped thin iron plates in the rigid direction on the outer periphery of a rotating shaft 1, and this iron core 2
A current-carrying outer skin 3 is provided around the outer periphery. The current-carrying outer skin 3 is made of a composite phase 9 of a conductive material 4 such as aluminum and a magnetic material 5 such as iron, and the magnetic material 5 is arranged in the radial direction (radial direction). Note that the iron core 2 may be in the form of a block instead of a laminate.

In a rotor with such a configuration, consider that the condition of the outer peripheral surface is that the teeth and conductors of the core of the squirrel-cage rotor exist in an infinitely uniform distribution in the circumferential direction. Magnetic fluctuations on the outer circumferential surface are dispersed in the circumferential direction and become extremely small, and electromagnetic vibration noise is much smaller than that of a squirrel cage rotor.In addition, by arranging the magnetic materials 5 in the radial direction, the current-carrying outer skin 30 Relative magnetic permeability μθ between the locals and relative magnetic permeability μ in the radial direction
The relationship of r is μθ<, and magnetic anisotropy is imparted. The relationship between this μθ2μm and the motor output is as shown in FIG. In other words, in order to increase the motor output, it is effective to make μθ as small as possible and μr as large as possible, but in reality, when the relative magnetic permeability μθ in the circumferential direction is 10 or less and the relative magnetic permeability in the radial direction is It can be seen that if the magnetic permeability μ is 100 or more, there is no significant difference in the maximum output that can be obtained.Now, the problem of the present invention is how to manufacture this newly conceived composite material rotor. In particular, in order to impart magnetic anisotropy in the circumferential and radial directions to the current-carrying outer skin of the rotor, magnetic materials must be arranged in the radial direction within the conductive material. The problem is how to easily manufacture the iron core.The usual idea is to coat the outer periphery of the iron core with a conductive material to a desired thickness, then drill countless holes in the conductive material in the radial direction. This method involves embedding thin magnetic wires in the holes, but this method has the disadvantage that manufacturing is troublesome and inefficient, leading to increased costs.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned technical problems and to provide a method for easily and efficiently manufacturing a composite rotor, and an apparatus for use in the method.

In order to achieve this object, the present invention provides a method for manufacturing a composite rotor in which a current-carrying outer skin made of a composite material of a conductive material and a magnetic material is provided on the outer periphery of a rotor core. It is arranged coaxially in a mold having a mold part with a large inner diameter, and the iron core is placed in a casting space between the core and the mold.
A radial magnetic field is applied to the casting space to arrange the magnetic material in that direction, and a molten conductive material placed in the casting space maintains the radial arrangement of the magnetic material. Further, the apparatus of the present invention used for carrying out this manufacturing method has a mold part with an inner diameter larger than the outer diameter of the rotor core, and the above-mentioned mold is placed in the mold cavity. A magnetic passage part side consisting of a mold that coaxially accommodates the iron core, an outer magnetic pole part surrounding the outer periphery of this fJ8 child, a central magnetic pole part that contacts the central member of the iron core, and a yoke part that connects these magnetic pole parts. , and a coil wound around the center magnetic pole portion of the magnetic path member. Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Factor 4 and FIG. 5 show an embodiment of the manufacturing method and apparatus of the present invention.

In FIG. 4, 2 is the iron core of the rotor explained in FIG. 1, and core holding plates &A and 6B are arranged on both sides of this iron core 2. The iron core 2 is housed coaxially in a cylindrical mold 7 having an inner diameter larger than its outer diameter, and placed on a mold bottom plate 8. A mandrel 9 passing through the center of the core 2, the core holding plates 5A, i5B, and the mold bottom plate 8 has a flange portion 10 at one end that is engaged with the bottom surface of the mold bottom plate 8, and a male threaded portion 11 at the other end. ing. Note that the cylindrical mold 7 is fitted onto the outer periphery of the mold bottom plate 8. In this state, the iron core 2 is placed coaxially within the cylindrical mold I, so there is a casting space 12 between the iron core 2 and the cylindrical mold γ for forming the current carrying skin 3 (see the first factor). Formed [, in addition, the core holding plate 6
A, 6B, the cylindrical hook mold 7 and the mandrel 9 are made of a magnetic material, and the mold bottom plate 8 is made of a non-magnetic material. ) In order to generate a radial (radial) magnetic field within the casting space 12, a magnetic field generator 15 consisting of a magnetic passage member 13 and a coil 14 is provided. The magnetic passage member 13 is
An outer peripheral magnetic pole part 16 that surrounds the outer periphery of the cylindrical casting m7 and faces the outer peripheral surface of the iron core 2 therein, a center magnetic pole part 17 that abuts the bottom surface of the mandrel 9, and a yoke part 18 that magnetically connects them. It is composed of. The coil 14 is wound around the central magnetic pole portion 1γ, and is connected to the power source 20.

With the above configuration, from the center magnetic pole part 17 to the core metal 9 and the iron core 2.
, a magnetic circuit is created that passes through the casting space 12, the cylindrical mold 7, the outer magnetic pole part 16, and the yoke part 18 and returns to the center magnetic pole part 17.When t-f is passed through the coil 14, a magnetic flux Φ as shown by the broken line is created. This generates a radial magnetic field in the casting space 12.
.

In this state, in the casting space 12, a diameter of 03~l, Qrnm is placed in a length corresponding to the radial thickness of the casting space.
When the magnetic wires 5W of about 200 mm are introduced, the magnetic wires 5W will be oriented in the radial direction due to the action of the magnetic field. The magnetic thin wire 5W is introduced evenly in the circumferential direction, and when it reaches a suitable level, it is removed by the non-magnetic pushing ring 22.
, Push the thin wire 5W toward the mold bottom plate 8. Repeat this insertion and pushing, until the magnet 4! When the stacked height of the L thin wires 5W becomes the same as the stacked width of the iron core 2, fit the mold upper shoe 23 as shown in FIG. 11 and tighten the nut 24. Due to this tightening, the magnetic wires 5W arranged in the radial direction within the casting space 12 are fixed in position.
In this state, the power supply to the coil 14 is stopped, and the entire inside of the cylindrical mold 7 is extracted from the magnetic field generator 15.

The whole inside of the cylindrical mold 7 that has been extracted is set in a vacuum chamber 25 as shown in FIG. Vacuum chamber 25
The base plate 26 is made of 4L of molten metal of a conductive material such as aluminum.
It is provided so as to cover the crucible 28 containing the crucible. The crucible 28 is heated in an electric furnace 29 and contains 4L of molten metal.
is kept at a predetermined temperature. Inside the molten metal 4L is a pipe 3 for sucking up the molten metal attached to the bottom of the plywood 26.
0 is inserted, and a branch passage 31 for distributing the molten metal 4L in the circumferential direction is formed in the plywood 26 so as to communicate with the pipe 30.

On the other hand, the mold bottom plate 8 is formed with a hot water hole 32 that communicates with the casting space 12 in correspondence with each branch passage 311C, and the mold upper lid 23 is provided with a gas for removing waste from the casting space 12. A punch hole 33 is formed.

In this state, the vacuum bonder 34 is operated to remove gas from the vacuum chamber 25 and make the chamber 25 a vacuum. As a result, the inside of the casting space 12 is also made vacuum. Next, the compressor 35
When the melt level in the crucible 28 is pressurized by operating the molten metal 4,
L flows into the casting space 12 through the pipe 30, the branch passage 31, and the hot water hole 32. The magnetic #1 wire 5W is made of iron wire, etc., and does not melt at the temperature of 4L of molten metal of conductive material.
The molten metal 4L should not enter the gap between the magnetic wires 5W.

At this time, in order to prevent the molten metal 4L from cooling and solidifying immediately, it is desirable to preheat the entire area within the cylindrical mold 7. Once the gap between the molten metal 4L'h'' and the magnetic wire 5W is completely filled, The pressurization by the compressor 35 is stopped, and the entire inside of the cylindrical mold 7 is cooled. By this cooling, the molten metal 4L filled in the gap between the magnetic wires 5W is solidified and becomes the conductive material 4 (see FIG. 2).

When the molten metal 4L has solidified, take out the entire cylindrical mold γ from the vacuum chamber 25, remove the nut 24, and remove the mold lid 23, the cylindrical mold 7, the mold bottom plate 8, etc.
A current-carrying outer sheath 3 made of a composite material of the conductive material 4 and the magnetic thin wires 5W embedded in the conductive material 4 in the radial direction is formed around the outer periphery of the iron core 2 (see FIGS. 1 and 2). Further, since the iron core 2 is combined with the cast-in conductive material 4 and integrated with the current-carrying outer skin 3, all that is left to do is to insert the rotating shaft 1 into the iron core 2, and a rotor as shown in FIG. 1 is completed.

In this way, according to this embodiment, it is possible to easily arrange innumerable magnetic 4411 wires inserted into the casting space between the iron core and the cylindrical mold in the radial direction, and the gaps between the magnetic wires can be easily arranged. It is possible to easily produce an electrified layer by casting a conductive material into 4) O and thereby tJ
Since the current-carrying outer skin is made of thin magnetic wires, the relative magnetic permeability in the radial direction is large, and the relative magnetic permeability in the circumferential direction (the magnetic wire has a magnetic flux between the thin magnetic wires) is large. Since it is packed, it becomes much smaller than that in the radial direction, and has magnetic anisotropy. This figure shows the relationship between S() and relative magnetic permeability μθ, 11r in the circumferential direction and the radial direction.

By doing this, we can determine the ratio of μθ and μ appropriately using the space factor 8f of [a ll1ll M.
Therefore, the output characteristics of the rotary electric motor manufactured as described above are determined by the occupation rate of the magnetic g-thin wire.

FIG. 7 shows another embodiment of the manufacturing method and apparatus of the present invention Q). In this figure, parts that are the same as or equivalent to those in FIG. A mixed hot water 36 made by mixing magnetic powder 5P such as iron powder into the bath water 41 of the material is poured. Therefore, no hot water holes are provided in the mold bottom plate 8. When the mixed molten metal 36 is injected in an amount equivalent to the laminated thickness of the iron core 2, before it is assimilated, the coil 14 is energized, a radial magnetic field is applied to the mixed molten metal 36, and the magnetic powder 5P therein is radiated. Arrange in the direction. The bale is cooled while a magnetic field is applied to solidify the mixed molten metal 36. Kon
As a result, on the outer periphery of the iron core 2, a current-carrying outer skin is formed, which is made of a composite material of the conductive material and the magnetic powder arranged in the radial direction therein. However, in this method, since the coil 14 is heated when the mixed molten metal is mixed, it is necessary to use a heat-resistant coil or to cool the coil 14 by flowing water or the like.

Note that even in the case of the first embodiment described above, after inserting a magnetic 11III wire with a predetermined sound into the casting space and arranging the wires in the radial direction by a magnetic field, mlJ is applied while the magnetic field is still applied. Alternatively, bathwater made of conductive material may be poured into the closed space.

As explained above, according to the present invention, the rotor core is installed in a mold, and a radial magnetic field is applied to the casting space created between the core and the mold to arrange the magnetic particles in the radial direction. Therefore, the magnetic material can be arranged very easily and efficiently, and by solidifying the molten metal in the casting space with the magnetic material arranged in the radial direction,
The magnetic permeability in the radial direction is much greater than that in the circumferential direction (and there is an advantage that a conductive outer skin can be easily formed on the outer periphery of the iron core).

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway perspective view showing an example of a composite material rotor;
Figure 2 is an enlarged section of part A in Figure 1 [Figure 111 and Figure 3 are the relative magnetic permeability μr in the radial and circumferential directions of the current-carrying outer skin of the rotor.
, μθ and 1! FIG. 4 is a longitudinal sectional view showing an embodiment of the manufacturing method and apparatus of the present invention; FIG. 5 is a sectional view showing another process in the same embodiment;
Figure 6 shows the relative magnetic permeability μr and μθ in the radial and circumferential directions of the current-carrying outer skin of the rotor manufactured according to the same example, and the magnetic property a.
FIG. 7 is a vertical sectional view showing another embodiment of the manufacturing method and apparatus of the present invention. 1...Rotating shaft, 2...Rotor core, 3
・・・・・・Electricity-conducting outer skin, 4・・・Conductive material, 4L
... Molten metal of conductive material, 5 ... Magnetic material, 5W ... Magnetic thin wire, 5P ... Magnetic powder, 7 ... Cylinder Mold, 8... Mold bottom plate, 9... Mandrel (center member), 12...
Casting space, 13...Magnetic passage member, 14...
...Coil, 15...Magnetic field generator, 16...
......Outer magnetic pole part, 1γ...Central magnetic pole part, 1
8...Yoke section, 23...! 1. J-shaped top lid. 1st Year 2 Figure 73' Year 4 Figure 2 T5 Figure

Claims (1)

[Claims] 1. A method for forming a current-carrying outer skin made of a composite material of a conductive material and a rupture material on the outer periphery of a rotor core, the core comprising:
The magnetic material placed in the casting space between the iron core and the mold is placed coaxially in a mold having a mold cavity with an inner diameter larger than the outer diameter thereof, and the magnetic material placed in the casting space between the core and the mold is shaded with a radial magnetic field in the casting space. and arranging it in that direction, and entering the casting space.
A method for manufacturing a composite rotor, comprising cooling and solidifying a molten conductive material while maintaining the radial alignment of the magnetic material. 2. In claim 1, the magnetic material is a magnetic thin wire, and after the mother wire is arranged in a radial direction within the casting space, a molten metal of the conductive material is injected into the casting space. 3. In claim 1, the magnetic material is magnetic powder, and the magnetic material is a molten metal of a conductive material mixed with magnetic powder. 1. A method for manufacturing a mixed material type rotor, characterized in that the magnetic powder injected into a casting space is arranged in a radial direction. 4. In an apparatus for forming a current-carrying outer skin made of a composite material of a conductive material and a magnetic material on the outer periphery of a rotor core, a mold B having an inner diameter larger than the outer diameter of the core is provided, and the core is placed in the cavity of the mold B. a magnetic path member consisting of a mold coaxially housing the mold, an outer magnetic pole part surrounding the outer periphery of the mold, a central magnetic pole part in contact with the central member of the iron core, and a yoke part connecting these magnetic pole parts; 1. An apparatus for manufacturing a composite rotor, comprising: a coil wound around a central magnetic pole portion of a member.