JP3261787B2 - Rotor for electric motor and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotor for a motor in which a rotor conductor and an end ring are formed by aluminum die-casting, and a method of manufacturing the same.

[0002]

BACKGROUND ART FIG. 4, for example, JP 57-17005
FIG. 7 is a perspective view showing a conventional motor rotor disclosed in Japanese Patent Application Laid-Open No. 5-2005. In the drawing, (1) is a rotor core, and (3) is a dummy shaft that is press-fitted into the inner wall of the rotor core (1) in advance when forming an end ring and a rotor conductor by aluminum die casting. .

[0003] Next will be described with reference to FIG. 6 for its production method. First, a punched thin-plate rotor core (1)
Then, a skew (oblique groove) forming step of shifting the position of the rotor conductor (not shown) in the rotor core so as not to overlap in the circumferential direction is performed, and further, the dummy shaft (3) is stacked. A rotor conductor (not shown) which is press-fitted into the inner wall of the rotor core (1), and penetrates the rotor core, and an end ring connecting the ends thereof are integrally formed by aluminum die casting. Next, after release, the dummy shaft (3) was pulled out, and the laminated core (1) was removed.
The outer wall and the inner wall are finished to predetermined dimensions by machining.

FIG. 5 is a sectional view showing a conventional motor rotor disclosed in Japanese Patent Application Laid-Open No. 63-181650. In the figure, (2) is an end ring formed by aluminum die-casting, (4) is a sleeve, (5) is a cylindrical permanent magnet, (6) is a non-magnetic cylinder made of stainless steel, etc., and (7) is This is a crankshaft fitted to the sleeve (4).

Next, a method of manufacturing the same will be described. A cylindrical permanent magnet (5) is set in the non-magnetic cylinder (6), and a sleeve (4) is coaxially inserted into the cylindrical permanent magnet (5). ).

[0006]

Since the conventional motor rotor shown in FIGS. 4 and 6 is manufactured through the above-described steps, the inner wall is a roughened surface because the inner wall is a laminated core. Therefore, machining finish is not easy, and it is difficult to obtain high-precision shape tolerances such as cylindricity and roundness. Therefore, when the diameter of the inner wall surface is changed with the same rotor core or when a high-precision shape tolerance is required, it is necessary to insert and process the sleeve after the aluminum die casting.

Further, in the conventional example shown in FIG. 5 , it is difficult to position the sleeve in the axial direction, and the sleeve is easily deformed because the pressure of the aluminum die cast is directly applied to the sleeve.
When the crankshaft is fitted, there is no counter bore, so that there is a problem that flexure of the crankshaft cannot be flexibly handled.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has a cylindrical shape inserted into the inner wall of a laminated rotor core during the manufacturing process while suppressing an increase in cost. An object of the present invention is to provide an electric motor rotor having a sleeve and capable of flexibly coping with bending of a crankshaft and a method of manufacturing the same, and to reduce the number of steps and cost.

[0009]

In order to achieve the above object, a rotor for an electric motor according to the present invention has a rotor conductor penetrating a laminated rotor core and an end portion of the rotor conductor. In an aluminum die-cast rotor in which an end ring connecting the rotor core is integrally formed by aluminum die-casting, a counter bore is formed inside the end of the laminated rotor core, and the counter of the laminated rotor core is formed. long cylindrical sleeve than the axial length of the inner wall is an inner portion which is not provided with the bore being more inserted fixed to the shrink-fitting or pressure Irito the inner wall of the rotor core, more crankshaft on the inside The main configuration is that it is shrink-fitted and fixed.

According to a second aspect of the present invention, there is provided a method of manufacturing a rotor for an electric motor, wherein a counter bore is formed inside an end portion.
Laminating a punched thin-plate rotor core, and rotating the cylindrical sleeve longer than the axial length of the inner wall of the laminated rotor core, which is the inner portion where the counter bore is not provided. A step of shrink-fitting or press-fitting the inner wall of the child core, and a rotor core having the sleeve inserted therein, a rotor conductor passing therethrough, and an end ring connecting end portions of the rotor conductor. It consists of a step of integrally forming by aluminum die-casting, and a step of shrink-fitting and fixing a crankshaft to the inside of the sleeve, which is formed integrally.

[0011]

In the rotor for an electric motor according to the present invention, a cylindrical sleeve is inserted before aluminum die-casting, so that a dummy shaft is not used as in the prior art. Since the rotor core is not pulled out, bending and displacement of the laminated rotor cores due to the pulling out are eliminated, and by using a high-precision sleeve, machining can be performed only on the outer wall of the laminated core. Therefore, the number of work steps is reduced and the cost is reduced. Further, since the counterbore is formed at the inside of both ends of the rotor core, the sleeve has a flexible structure, and can flexibly cope with bending (bending) of the crankshaft.

[0012]

[Embodiment 1] An embodiment of the present invention will be described below with reference to the drawings. FIG.
FIG. 2 is a schematic view showing a manufacturing process, FIG. 2 is a cross-sectional view showing a main part of the motor rotor of this embodiment, and FIG. 3 is an explanatory view showing the operation principle. In the drawing, (1) is a rotor core, (2) is an end ring located at both ends of the rotor core, and a rotor conductor (not shown) is arranged at a position near the outer periphery in the rotor core (1). And is connected to the end ring. The end ring (2) and the rotor conductor are integrally formed by aluminum die casting. (4) is a cylindrical sleeve inserted into the inner wall of the rotor core (1), (7) is a crankshaft shrink fit inside the sleeve (4),
(8) is a counterbore formed in the inside of both ends of the rotor core (1), that is, a ring-shaped gap (8). As apparent from the figure, the sleeve (4) has the axial length of the inner portion (defined as the inner wall of the rotor core) of the laminated rotor core (1) where the counter bore (8) is not provided. It is formed longer.

Next, the manufacturing process will be described. First, a punched thin-plate rotor core (1) is laminated. At this time, the counterbore (8) is formed by using the first and last several plates having a large inner diameter for lamination. Subsequently, the laminated rotor core (1) is heated to, for example, 300 ° C. through a skew (oblique groove) forming step of shifting the positions of the holes so as not to overlap in the circumferential direction, and a cylindrical sleeve ( 4) Insert and shrink fit. After inserting these into a die-casting mold, closing the mold, and performing aluminum die-casting, the rotor conductor and end rings (2) connected to both ends thereof are integrally formed by aluminum die-casting. You. The outer wall of the rotor core (1) among the products taken out of the mold is machined to predetermined dimensions. Then, to secure shrink fit crank shaft (7) inside the sleeve (4).

Next, the operation of the motor rotor manufactured as described above will be described. Figure 3 shows the crankshaft
(7) is exaggeratedly shown, for example, the case where the eccentric load or the like is loaded and bent in a rotary compressor or the like,
In this embodiment, a counterbore (8) is formed and a sleeve
Since (4) is formed longer than the axial length of the inner wall of the rotor core, even if the crankshaft (7) may bend, the part (4a) that is part of the sleeve (4) also follows. And respond flexibly.

[0015]

As described above, according to the present invention, the cylindrical sleeve is inserted into the inner wall of the laminated rotor core by shrink-fitting or press-fitting before the aluminum die-casting. No dummy shaft is used, and it is not necessary to pull out the dummy shaft after aluminum die casting. Furthermore, by using a high-precision cylindrical sleeve, it is possible to omit difficult machining of the rough inner wall of the rotor core after aluminum die-casting. There are effects that can be done.

In addition to the above effects, a laminated core having a counter bore is used, and the sleeve is formed to be longer than the axial length of the inner wall of the rotor core. There is an effect that it is possible to flexibly respond to bending (bending).

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a manufacturing process of a motor rotor according to an embodiment of the present invention.

FIG. 2 is a schematic sectional view showing a main part of a motor rotor according to the embodiment.

FIG. 3 is an explanatory diagram showing the operation principle of the motor rotor of the embodiment.

FIG. 4 is a perspective view showing a conventional motor rotor.

FIG. 5 is a cross-sectional view showing another conventional motor rotor.

FIG. 6 is a schematic sectional view showing a manufacturing process of a conventional motor rotor.

[Explanation of symbols]

1 rotor core, 2 end rings, 4 sleeves, 7
Crankshaft, 8 counterbore.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Susumu Kawaguchi 3-18-1, Oka, Shizuoka-shi Mitsubishi Electric Corporation Shizuoka Works (56) References JP-A-53-35105 (JP, A) JP-A Sho 54-97720 (JP, A) JP-A-59-136053 (JP, A) JP-A-56-102981 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H02K 17/16 H02K 15/02

Claims (2)

(57) [Claims] 1. An aluminum die-cast rotor in which a rotor conductor penetrating a laminated rotor core and an end ring connecting end portions of the rotor conductor are integrally formed by aluminum die-casting. A counterbore is formed inside the end of the rotor core, and the cylindrical sleeve that is longer than the axial length of the inner wall of the laminated rotor core, which is the inner side where the counterbore is not provided, is rotated by the rotation. is inserted and fixed by shrink fit or press-fitted into the inner wall of the child core, baked further crankshaft on the inside
A rotor for an electric motor, wherein the rotor is fitted and fixed. 2. A step of laminating a punched thin-plate rotor core so that a counter bore is formed inside the end portion, and an inner portion of the laminated rotor core where the counter bore is not provided. Inserting a cylindrical sleeve longer than the axial length of the inner wall into the inner wall of the rotor core by shrink-fitting or press-fitting, and a rotor core having the sleeve inserted therein and rotating through the rotor core. From the step of integrally forming the child conductor and the end ring connecting the ends of the rotor conductor by aluminum die casting, and the step of shrink-fitting and fixing a crankshaft to the inside of the sleeve, although formed integrally, Manufacturing method of a rotor for an electric motor.