JPH11191942A - Stator core for frameless motor, manufacture of the stator core and molding die for internal chill for manufacturing the stator core - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize high-precision assembly without deviation between a center hole and outer shape, by laminating a number of donut-shaped sheet metals and inserting in a core bar located at the center of internal chill of a laminated body formed to cylindrical shape, laminating surface shape of an armoring body, and forming a stator core in reference to the hole in the laminated body. SOLUTION: A cavity 2 comprising a circular columnar recessed portion with the upper surface released is formed in a main body for forming die for internal chill, an outer periphery of a stator core to be manufactured is aligned with the inner side for manufacture, and a core bar 3 to be erected having a diameter equivalent to the center hole of the stator core to be manufactured is erected. A bottom surface of a lid body 5 for closing and sealing the released top surface of the cavity 2 sticks out the fitting portion 7 so as to surround the periphery of a bottomed hole 6 for inserting the core bar 3, and a pouring gate 8 is drilled at the side portion. Then, the sheet metals are made integrally by the internal chill so that no traces of welding remain and a frameless body can be neatly produced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stator core of a frameless motor (hereinafter simply referred to as "stator core").

[0002]

2. Description of the Related Art As shown in FIG. 7, a frameless motor has bearings 16a (16 ') at both ends of a stator core M.
a), the rotor 17 is placed in the case formed by fixing the covers 16 and 16 ′ provided with the bearings 16 a and 16 ′.
a, and the stator core M is inserted in a state of being penetrated, and the stator core M is shared with the frame to substantially omit the frame. Conventionally, as shown in FIG. 8, the stator core is formed by laminating donut-shaped metal thin plates 9a, 9a,... And fixing plates (end plates) 17, 17 on both end surfaces thereof, respectively.
The end plates 17, 17 and the metal thin plates 9a, 9a,.
Are integrated by performing beam welding of a plurality of strips continuously on their peripheral surfaces in the stacking direction.
7 has fitting portions 13, 1 for assembling the cover.
No. 3 was formed. Therefore, in order to form a fitting portion for assembling the cover, as shown in FIG. 9, a dedicated jig 18 called a collet is mounted and set on a machine tool, and the end face is machined.

[0003]

It is inefficient if a jig is mounted and cutting is performed one by one. Therefore, the applicant has proposed an attempt to simultaneously form the fitting portion by casting the entire body with metal, reduce the number of parts, and omit the finishing of the peripheral surface and the end surface processing. The center hole of the stator core is the same as the hole in the metal sheet used for the inner peripheral surface, so if the cast-in position of the metal sheet shifts even a little, the positional relationship between the center hole and the fitting part will be incorrect. When assembled, the center axes of the rotor and the stator core do not coincide with each other, resulting in a non-uniform gap.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a stator core of a frameless motor which can be assembled with a rotor and a bearing member with high accuracy. A stator core of a frameless motor formed by laminating a large number of sheets to form a cylindrical laminated body and casting the laminated body in a metal outer casing, wherein the laminated body is a molding die for stuffing. The stator core of the frameless motor whose surface shape is formed with reference to the hole of the laminated body by being fitted into the mandrel arranged at the center of the By laminating a large number of donut-shaped metal thin plates in the molding die while being fitted into the mandrel, each metal thin plate is set on the basis of the hole with respect to the molding die, and the molding for the cast-in is performed. Block mold By injecting the molten metal Te,
A method for manufacturing a stator core of a frameless motor in which a fitting portion is integrally formed with a fitting portion forming portion provided in a molding tool for assembling with the cored bar as a reference, and at the center of the cavity, A mandrel for fitting donut-shaped thin metal plates is provided for stacking a large number of doughnut-shaped metal sheets. There is a mold for the whole. The stator core is provided with a fitting portion forming portion for a molding insert, and the fitting portion is formed integrally with the exterior body, or a through hole is provided at the same position in each metal thin plate. Thus, a through-hole can be formed in the laminate, and the inside of the through-hole can be filled with the same metal for casting as the exterior body. Further, it is desirable to form a taper on the periphery of the front end of the mandrel.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A stator core according to the present invention, a method for manufacturing the same, and a mold for assembling will be described with reference to the drawings. In FIG. 1, reference numeral 1 denotes a molding die body for insert molding. The molding die body 1 has a cavity 2 formed of a cylindrical concave portion whose upper surface is open, and the inner periphery of the cavity 2 is to be manufactured. A metal core 3 having a diameter corresponding to the center hole of the stator core to be manufactured is provided upright at the center of the bottom surface so as to match the outer periphery of the core. The upper end of the mandrel 3 protrudes from the upper surface of the molding die body 1, and the periphery of the upper end is formed as a tapered surface. Also, the bottom surface of the cavity 3 has a raised bottom structure in which the fitting portion forming portion 4 is provided so as to surround the core metal 3 so that the inner side is raised by one step by the fitting portion forming portion. 5 closes the open upper surface of the cavity 2,
A lid for sealing the cavity 2, wherein the bottom surface of the lid 5 is formed by projecting a fitting portion forming portion 7 so as to surround a bottomed hole 6 into which the mandrel 3 is fitted. It is formed symmetrically with the raised bottom structure, and a gate 8 is formed on the side thereof.

Reference numerals 9a, 9a, 9a,... Denote donut-shaped metal thin plates serving as a base material of the stator core, and the metal thin plates are obtained by stamping and forming silicon steel plates. Each of the metal thin plates 9a, 9a, 9a,... Has an inner periphery and an outer periphery that match the stator core to be formed. The small through holes 10a, 10a,.
Is provided.

To manufacture the stator core, first, the metal thin plates 9a, 9a, 9a,.
Are laminated in the cavity 2 while being fitted, to form a laminated body 9. The thin metal plate 9a is easily fitted by the tapered end portion of the mandrel 3, and the formed laminated body 9 is in close contact with the mandrel 3 and is accurately positioned based on the mandrel 3. The metal thin plates 9a, 9a, 9a,.
The positions of the small through holes 10a, 10a,.
The laminated body has small through holes 10a, 10a,.
To form Next, the lid 5 is closed to close the cavity 2, and molten metal such as aluminum or iron is injected from the gate 8. The molten metal is filled from the upper space of the cavity 2 closed by the lid 5 into the lower space through the through hole 10,
When the mold is released after solidification, as shown in FIG. 3, the upper and lower surfaces of the laminated body 9 are completely covered with the solidified metal exterior body 11, and those exterior bodies 11 are rod-shaped portions 12 penetrating through the through holes 10. Are connected to each other so as to be integrally connected, and fitting portions 13.13 are formed on both surfaces.

The stator core M thus formed
Since the outer body 11 on both the front and back sides is formed based on the mandrel 3, there is no deviation between the fitting portion 13.13 and the central hole 14 and the precision is formed with high accuracy. No modification is required. Also, metal thin plates 9a, 9a, 9a
.. Are sandwiched from above and below by the exterior bodies 11 and 11 and are connected and integrated by the rod-shaped portions 12, so that there is no need for welding or other coupling means, and a beautiful laminated pattern of thin plates is maintained. .

Although the stator core of the above embodiment exposes the entire outer peripheral surface of the laminated body 9, a thin metal plate having an outer diameter smaller than the outer diameter of the stator core to be manufactured is used. As shown, the entire body including the outer periphery can be covered with the exterior body 11, and in this case, the standard is only the center hole 14.
, There is no displacement between the fitting portions 13, 13. Further, a vertical groove is formed on the inner peripheral surface of the cavity, and as shown in FIG. 5, the outer periphery of the laminated body 9 is surrounded by a frame-shaped outer package 11, or heat is radiated to the outer package 11 as shown in FIG. The fins 15, 15,... May be integrally formed, and the form of the cast-in of the stator core M may be appropriately changed.

Further, the molding die can be appropriately changed such that the mandrel and the fitting portion forming portion can be detached, placed in a horizontal position, or divided into two parts. Further, the fitting portion may adopt any form, such as a combination of a hole and a pin, a concave portion and a convex portion, which fit each other, as long as they can be positioned and fitted to each other. And the type of the metal thin plate to be the base material, the metal for the as-cast is not limited to the examples,

[0011]

The stator core of the present invention has an outer body formed with reference to the center hole, so that the accuracy is high, there is no displacement between the center hole and the outer shape, and a thin metal plate is formed by casting. Since it is integrated, it has good appearance without welding marks and is suitable for frameless. In particular, if the fitting portion is integrally formed with the exterior body by a molding die having a fitting portion forming portion, the fitting portion is formed at an accurate position with respect to the center hole, so that the fitting portion is formed. No centering or cutting is required to form. Also, if a through hole is formed in a thin metal plate and the through hole is formed in the laminated state in a laminated state, the laminated body is integrally joined by the as-filled metal that fills the through hole, which is troublesome. Welding can be eliminated. Furthermore, according to the manufacturing method of the present invention, the exterior body based on the center hole can be easily formed, and the manufacturing method can be similarly performed by using the mold of the present invention. By providing a taper at the tip of the mandrel in the molding die, the laminating operation of the metal thin plates becomes easy.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a method of manufacturing a stator core according to the present invention.

FIG. 2 is a sectional view showing a method for manufacturing a stator core according to the present invention.

FIG. 3 is a perspective view of a completed stator core.

FIG. 4 is an explanatory view showing a modified example of a stator core.

FIG. 5 is an explanatory view showing another modification of the stator core.

FIG. 6 is an explanatory view showing still another modification of the stator core.

FIG. 7 is an explanatory diagram showing a structure of a frameless motor.

FIG. 8 is an explanatory diagram of a conventional example.

FIG. 9 is an explanatory view showing processing of a fitting portion using a jig.

[Explanation of symbols]

1. Mold body, 2. Cavity, 3. Mandrel, 4
..Mating portion forming portion, 5 ·· Lid, 6 ·· Bottomed hole,
7. Fitting portion forming part, 8. Gate, 9a ... Metal thin plate, 9 ... Laminated body, 10 ... Small through hole, 10 ... Through hole, 11 ... Exterior body, 12 ... Rod Shaped part, 13 fitting part, 14 center hole, 15 fin, 16, 1
6 '· · · cover, 16a, 16' a · · · bearing, 17 ·
· Fixing plate, 18 · · · jig, M · · · stator core.

Claims (6)

[Claims] 1. A stator core of a frameless motor formed by laminating a number of donut-shaped thin metal sheets to form a cylindrical laminated body, and casting the laminated body in a metal outer casing. A stator core of a frameless motor in which the surface shape of the exterior body is formed with reference to the holes of the laminate by fitting the laminated body into a mandrel arranged at the center of a molding die for assembling. . 2. The stator core of a frameless motor according to claim 1, wherein the insert mold has a fitting portion forming portion, and the fitting portion is formed integrally with the exterior body. 3. A through hole is formed in the laminated body by providing a through hole at the same position on each metal thin plate, and the inside of the through hole is filled with the same metal for casting as the exterior body. Or the stator core of the frameless motor described in 2. 4. A plurality of donut-shaped metal thin plates are stacked in a molding die for assembling in which a mandrel is disposed at the center while being fitted in the mandrel, thereby forming each metal thin plate. The mold is set on the basis of the hole, the molten metal is injected by closing the mold for molding, and the fitting provided in the molding for molding with the mandrel as a reference for positioning. A method for manufacturing a stator core of a frameless motor in which a fitting portion is integrally formed at a fitting portion forming portion. 5. A mandrel is provided at the center of the cavity for stacking a large number of donut-shaped thin metal plates to be laminated, and each of the mating portions is fitted to each surface of the cavity orthogonal to the axial direction of the mandrel. Cast-in molds for manufacturing stator cores with formed parts. 6. The insert mold for manufacturing a stator core according to claim 4, wherein a taper is formed at a peripheral edge of a front end of the mandrel.