JPH02237449A - Cast rotor and manufacture thereof - Google Patents

Abstract

PURPOSE:To manufacture a cast rotor having reduced blow hole efficiently by forming a rotor conductor of an Al alloy composed of 4-6wt.% Si, 1.0-1.5wt.% Cu, 0.1-0.5wt.% Fe, 0.1wt.% or less Cr, 0.05wt.% or less Mn, and the remainder of Al. CONSTITUTION:A rotor core 2 laminated with core element boards 5 is contained in a mold, then Al alloy molten composed of 5wt.% Si, 1.0wt.% Cu, 0.3wt.% Fe, 0.07wt.% Cr, 0.04wt.% Mn, and the remainder of Al is poured from the opposite end sections of the rotor core 2 into a slot 6 thus casting a rotor conductor and a cooling fin 9. by such arrangement, fluidity of the alloy molten is improved and a high quality rotor having reduced blow hole can be casted. Furthermore, since end ring, slot bar, cooling fin, and the like can be casted simultaneously, mass productivity of rotor can be improved.

Description

Detailed Description of the Invention (Objective of the Invention) (Industrial Application Field) The present invention relates to a U-shaped rotor used in an induction motor and a method for using the rotor, which has particularly high strength and is suitable for mass production. The present invention relates to a U-shaped rotor with excellent physical and electrical characteristics and a method for manufacturing the same.

(Prior art) Squirrel cage Li 7?, which has been widely used in the past. A rotor 1 of an electric motor is generally constructed by integrally assembling a rotor core 2 and a rotor conductor 3 to a rotating shaft 4, as shown in FIG. The rotor core 2 is formed by laminating a large number of core element plates 5 made of thin disc-shaped silicon steel plates, as shown in FIG. 3, in order to prevent losses due to eddy currents.
A slot 6 as shown in FIG. 4 is bored in the outer periphery of the holder.

The rotor conductor 3 has copper rods (slot bars) 7 arranged in a cage shape as shown in Fig. 5, and end rings (
They are joined together by a ring-shaped copper plate called short-circuit ring 8. Each copper rod 7 is inserted into a slot 6 of the rotor core 2 and fixed by end rings 8, 8 integrally joined to both ends of the rotor core 2.

The eddy current caused by the induced electromotive force circulates through the copper rod 7 and the end ring 8.8, and the rotor 1 is rotated by the electromagnetic force of the eddy current and the rotating magnetic field.

In recent years, cast rotors, in which the copper rods 7 and end links 8, 8 are cast and molded with molten pure aluminum, have come into widespread use as rotors used in low-output induction motors.

Die casting methods and low pressure casting methods are widely used as methods for manufacturing this cast rotor. The die casting method is a method of casting soft metal such as aluminum into a mold by applying pressure, while the low pressure casting method sends compressed air into a closed furnace and applies a low pressure of about 15 to 50 kPa inside the furnace. The aluminum lagoon is used to push up the molten lagoon and inject it into the mold.

In both cases, a large number of core element plates with slots drilled in advance are laminated and tightened, pure aluminum or its molten aluminum is injected into the slots, and rotor conductors including end rings and cooling fins are formed into a body. This is the way to do it.

According to this cast rotor, the rotor itself needs to be made slightly larger because conventional copper and aluminum materials have lower conductivity, but cooling fins can also be formed at the same time. It is widely used because it has excellent fillability.

(Problem to be Solved by the Invention) However, as mentioned above, as the rotor conductor material of conventional cast rotors, pure aluminum or an aluminum alloy material in which trace amounts of chromium, manganese, etc. are added to pure aluminum is mainly used. Because of this, its mechanical properties are poor.

The high-resistance material, which is pure aluminum with trace amounts of chromium and manganese added, is mainly used for high-torque electric appliances! ) II rotor conductor. Even with such a high-resistance material prepared based on pure aluminum, its strength characteristics at room temperature or high temperature are approximately the same as those of pure aluminum.

For example, the tensile strength at room temperature (20℃) is 7 to 8 kg/
1, and at 200°C, it becomes a low clay of about 2.0K9/d.

On the other hand, as a result of measuring stress in each part due to centrifugal force when the rotor rotates at 5000 revolutions per minute, a maximum stress of 1.9K9/1 was detected on the inner diameter side of the end ring. Therefore, with conventional materials, there is little margin for strength at high temperatures, and there is a risk that the end ring will be damaged during short-term operation.

Furthermore, when the rotor conductor is cast using pure aluminum, which is a conventional material, the flow (fluidity) of the molten metal passing through the slots is poor, and the product tends to have cavities, resulting in a shortened service life.

On the other hand, when an aluminum alloy with excellent fluidity is used, there is a drawback that the electrical characteristics of the motor deteriorate. In other words, the standard value of the electrical conductivity of the rotor conductor used in the ai
This is the value corrected as a percentage. ), and it has been difficult to select a material that satisfies this standard value, has high strength, and has good fluidity.

The present invention was made to solve the above problems, and has excellent strength characteristics even at room temperature and high temperature, good fluidity during casting, and good electrical characteristics as an electric IJ machine. The purpose of the present invention is to provide an excellent cast rotor and a method for manufacturing the same.

(Structure of the Invention) (Means and Effects for Solving the Problems) The inventors of the present application have conducted experiments with various types and compositions of alloy elements constituting the rotor conductor. 4% or more and 6% or less, copper 1.0% or more1.
5% or less, iron 0.1% or more and 0.5% or less, chromium 0
．． When a cast rotor is formed with a rotor conductor made of an aluminum alloy containing 1% or less of manganese, 0.05% or less of manganese, and the remainder substantially consisting of aluminum,
The first invention of the present application was completed based on the knowledge that a v-casting rotor with excellent strength characteristics, good fluidity of the material used during casting, and excellent electrical characteristics was obtained. be.

Further, the second invention of the present application is a method for manufacturing a V-casting rotor having a rotor core, a rotor conductor, and a cold U1 fin, in which a large number of core element plates having slots are stacked to form a rotor. Form an iron core, and then silicon in a weight percentage of 4% or more and 6% or less, copper as 1.0% or more and 1.5% or less,
An aluminum alloy melt lag consisting of 0.1% to 0.5% of iron, 0.1% or less of chromium, and 0.05% or less of manganese, the remainder being substantially aluminum, is applied to the end of the rotor core. The rotor conductor and the cooling fins are integrally cast into the rotor conductor and the slot i.

The reasons for the limitations of the present invention will be described below.

Silicon (S1) is added to improve the fluidity of the aluminum alloy sludge and enhance the castability.

The addition level of Si in general aluminum alloy casting materials is set at -611.7% by weight or less, which corresponds to the eutectic point between Δg and Si, but when added up to the eutectic point, the electrical conductivity significantly increases. decreases to Therefore, when used as a rotor, the range is set to 4 to 6%, which satisfies both properties of melt field fluidity and electrical conductivity.

Further, iron (Fe) is added to prevent high temperature brittleness and reduce casting damage. In particular, in areas where the cross-sectional area changes rapidly, such as the connection between the slot bar and the end ring, cracks are likely to occur due to shrinkage stress of the molten metal. Therefore, Fe is added to prevent the occurrence of cracks. If the amount of Fe added is less than 0.1%, the effect is small, while if the amount added exceeds 0.5%, AI-Fe
Since compounds are formed and the toughness is significantly reduced, the addition of
is set in the range of 0.1 to 0.5%.

In addition, copper (Cu) is dissolved in the An substrate to strengthen the substrate.
Added to improve the strength of rotor conductors. If the content of CU is less than 1.0%, the effect will be small, while if the content exceeds 1.5%, the fluidity of the aluminum alloy melt will decrease and the manufacturing efficiency of the rotor will decrease. , defects are more likely to occur.

Therefore, the amount of Cu added is set in the range of 1.0 to 1.5%.

Furthermore, chromium is added along with manganese to adjust the electrical conductivity of the rotor conductor, and if it exceeds 0.1%, the electrical conductivity will drop below that required for a high-torque rotor. Therefore, it is set to 0.1% or less.

Further, manganese forms a compound with Fe and improves corrosion resistance, but if the content exceeds 0.05%, the electrical conductivity decreases rapidly, so it is set to 0.05% or less.

As a result of using a certain aluminum alloy melt lagoon having the above composition, a high-quality cast rotor was obtained in which the flowability of the alloy melt during casting was extremely good and the occurrence of cavities was small. In addition, end rings, slot bars, cooling fins, etc., which were previously manufactured and assembled separately, are all integrated at the same time! 5
Because it was possible to manufacture rotors, the productivity of rotors could be greatly improved.

(Example) Next, an example of the present invention will be described with reference to the accompanying drawings.

As Examples 1 to 3, an aluminum alloy (AI-0.2%Or, 1%0.1
Si, Cu, and Fe components were added to Mn alloy) to prepare an aluminum alloy melt lagoon.

Here, Si, Cu, and Fe have the melting point of aluminum (6
60°C), 3i is added as an aluminum alloy containing 20% by weight of 81, while CU and l”e are added with 30% by weight of Cu and 101% of l”e, respectively.
It was added as an aluminum alloy containing ffi%, and the alloy composition was finally adjusted to each alloy composition shown in Table 1.

Next, as shown in FIG. 1, a rotor core 2 in which a large number of core element plates 5 with slots 6 are stacked is housed in a mold, and then the molten aluminum alloy of each composition described above is poured into the rotor core 2. Inject the rotor conductors and cold fins 9 into the ends and slots 6 as shown in FIG.
It was molded by casting using a manufacturing method. This cast rotor is a rotor for induction electric vJ, which is driven by a railway power vehicle for 1 hour.

Then, the flow properties of each aluminum alloy melt lagoon during casting were evaluated, and the electrical conductivity at 8.8 parts of the end ring of each obtained casting rotor was measured, and the results are shown in the right column of Table 1. I got it. The fluidity evaluation here is ◎, which has extremely good fluidity and can complete casting in a short time, and 0, which has good fluidity and can be used for normal casting operations, and 01, which has low fluidity and requires a long time to perform the casting operation. Let × be what you need 3
Evaluated in stages.

In addition, we use materials melted with each aluminum alloy composition,
Cast a test piece using a JIS mold for tensile test pieces,
A No. J134 tensile test piece was cut out from the obtained cast material, and the 0.2% proof stress, tensile strength, elongation, high temperature tensile strength at 200°C, and number of rupture cycles at a stress of 9 Ky/1 were measured, and the results are shown in Table 1. The results shown in the figure on the right were obtained.

On the other hand, as Comparative Examples 1 to 3, cast rotors were manufactured in the same manner as in Examples 1 to 3 using aluminum alloy melt lagoons or pure aluminum melt lagoons having the compositions shown in the left column of Table 1.

Further, as Comparative Examples 4 to 7, △C3A-F, △C4A-F. AC4C-F.
Select AC4D-F material and cast the rotor in the same manner as in Examples 1 to 3! iJ'75, and also evaluated the fluidity during casting for Comparative Examples 1 to 7, and further evaluated the electrical conductivity of the cast part,
The mechanical properties were measured and the results shown in Table 1 below were obtained.

[Margin below]

As is clear from the results in Table 1, in the range of alloy compositions shown in Examples 1 to 3, the fluidity of the aluminum alloy lagoon is good, there is little risk of formation of cavities, and the casting time is short. A cast rotor with excellent quality and souvenir value can be obtained. Also, the electrical conductivity is 31.0 to 31.31
ACS%, making it ideal as a rotor for high-torque induction motors.

In addition, the strength characteristic values not only at room temperature but also at temperature a are significantly improved compared to conventional examples (Comparative Examples 3 to 7).

On the other hand, in Comparative Example 1, although the electrical conductivity is high, the flowability of the molten metal is low, and casting operations are difficult. In addition, in Comparative Example 2, in which the largest amount of silicon was added, the fluidity of the material molten layer was extremely excellent, so the yieldability was excellent, but the electrical conductivity was low, making it unsuitable as a rotor for a high-torque electric motor.

In addition, although the alloy compositions shown in Comparative Examples 4 to 7 all have good melt fluidity, the electrical conductivity becomes too high, resulting in high torque induction! It can be seen that this material is unsuitable as a material for the rotor of the 71 aircraft.

As described above, according to the cast rotor and the manufacturing method thereof according to the present embodiment, it is possible to provide a rotor with appropriate electrical conductivity and excellent high-temperature strength.

In particular, the fluidity of the molten aluminum alloy lagoon used during casting is good, making it possible to efficiently produce high-quality rotors with fewer cavities.

Additionally, rotor components such as end rings, slot bars, and cooling fins, which were conventionally manufactured and assembled separately, can be integrally cast at the same time, greatly improving rotor productivity. can.

〔Effect of the invention〕

As explained above, according to the cast rotor and the manufacturing method thereof according to the present invention, the aluminum alloy molten lagoon has good fluidity, so a high-quality cast rotor with fewer cavities can be efficiently manufactured. be able to.

Further, according to the present invention, since the aluminum alloy composition has appropriate electrical conductivity and excellent high-temperature strength, it is possible to provide a rotor with excellent electrical and mechanical properties.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing an embodiment of a cast rotor according to the present invention, Fig. 2 is a perspective view showing an example of the structure of a conventional squirrel cage rotor, and Fig. 3 is an example of the structure of a conventional rotor core. 4 is a sectional view showing the cross-sectional shape of the slots 1 to 1. FIG. 5 is a perspective view showing an example of the structure of a conventional rotor conductor. DESCRIPTION OF SYMBOLS 1... Rotor, 2... Rotor core, 3... Rotor conductor, 4... Rotating shaft, 5... Core element plate, 6...
Slot, 7... Copper bar (slot bar), 8... End ring (short circuit ring), 9... Cooling fin. Applicant's agent Hisashi Hatano Figure 2-289-

Claims (1)

[Claims] 1. Silicon in weight percent from 4% to 6%, copper from 1.0% to 1.5%, and iron from 0.1% to 0.5%.
A cast rotor comprising a rotor conductor made of an aluminum alloy containing 0.1% or less of chromium, 0.05% or less of manganese, and the remainder being substantially aluminum. 2. In a method for manufacturing a cast rotor equipped with a rotor core, rotor conductors, and cooling fins, a number of slotted core element plates are laminated to form a rotor core, and then the weight percentage is Silicon 4% or more and 6% or less, copper 1.
Molten aluminum alloy containing 0% or more and 1.5% or less, iron 0.1% or more and 0.5% or less, chromium 0.1% or less, manganese 0.05% or less, and the balance being substantially aluminum. A method for manufacturing a cast rotor, characterized in that the rotor conductors and cooling fins are cast into the ends and slots of the rotor core, and the rotor conductors and cooling fins are integrally cast.