The present disclosure relates to a stator core plate manufacturing method, a stator core plate, a stator core, and a mold.
As a method of manufacturing a stator core of a motor, a method of laminating a plurality of stator core plates, obtained by punching a steel sheet into the shape of a stator core by a pressing device or the like, in the thickness direction is known. In the stator core manufactured by such a method, there is a case where a protrusion for providing an attachment hole or the like is formed on the outer periphery. In this case, the stator core plate is manufactured by punching a steel sheet in the shape of the stator core having the protrusion.
In a sheet metal member having a protrusion near an outer edge like the stator core plate having the protrusion described above, the protrusion may be plastically deformed when a steel sheet is punched with a mold. Examples of the factor of deformation of the protrusion include a variation in distribution of a punching stress caused by contact of the protrusion with the mold when the steel sheet is punched with the mold, and a variation in strength distribution in the protrusion.
As a manufacturing method for preventing such deformation of the protrusion, for example, a method of manufacturing a sheet metal member in which a portion having a lower strength than the protrusion is formed around the protrusion is known. In this manufacturing method, after a window portion is punched on a main body side of the protrusion, an entire outer shape including the protrusion and a main body is formed. That is, the entire outer shape is formed after the portion having a lower strength than the protrusion is formed in the main body. As a result, when the entire outer shape is formed, even if the protrusion comes into contact with the mold, the portion having a lower strength than the protrusion elastically deforms first, so that plastic deformation of the protrusion can be prevented.
In the case of manufacturing the portion having a lower strength than the protrusion as in the configuration described above, it is necessary to form a punched hole or the like on the main body side. However, in a stator core manufactured by such a manufacturing method, a space that prevents passage of a magnetic flux is generated in the main body of the stator core, and thus, there is a possibility that magnetic flux density generated in the stator core is reduced.
An example embodiment of a method of manufacturing a stator core plate according to the present disclosure is a method of manufacturing a stator core plate including a protrusion extending radially outward from a disk-shaped main body. This method of manufacturing a stator core plate includes forming at least a portion of an outer shape of the protrusion by punching a portion of a steel sheet to provide at least the portion of the outer shape of the protrusion, and forming the main body by punching the steel sheet in a shape continuous with the outer shape of the protrusion formed in the steel sheet.
The above and other elements, features, steps, characteristics and advantages of the present disclosure will become more apparent from the following detailed description of the example embodiments with reference to the attached drawings.
Hereinafter, example embodiments of the present disclosure will be described in detail with reference to the drawings. The same or corresponding portions in the drawings are denoted by the same reference numerals, and the description thereof will not be repeated. Further, the dimensions of elements in each drawing do not faithfully represent the actual dimensions of the constituent members, the dimensional ratio of each element, or the like.
Further, in the following description, a direction parallel to the central axis of a rotor is referred to as an “axial direction”, a direction orthogonal to the central axis is referred to as a “radial direction”, and a direction along an arc with the central axis as the center is referred to as a “circumferential direction”. However, there is no intention to limit the direction at the time of use of motors according to preferred embodiments of the present disclosure by the definitions of the directions.
Further, in the following description, the expressions such as “fixed”, “connected”, “joined” and “attached” (hereinafter referred to as “fixed” or the like) are not limited to the case where the members are directly fixed or the like to each other. It also includes the case where it is fixed or the like via another member. That is, in the following description, the expression such as fixation includes the meaning of direct and indirect fixation or the like between members.
The rotor 2 includes a shaft 20, a rotor core 21, and a magnet 22. The rotor 2 is located radially inside the stator 3 and is rotatable with respect to the stator 3.
In this example embodiment, the rotor core 21 has a cylindrical shape extending along the central axis P. The rotor core 21 is formed by laminating a plurality of electromagnetic steel sheets, formed in a predetermined shape, in the thickness direction.
The shaft 20 extending along the central axis P is fixed to the rotor core 21 in a state of penetrating in the axial direction. As a result, the rotor core 21 rotates with the shaft 20. Further, in the present example embodiment, a plurality of magnets 22 are located on the outer peripheral surface of the rotor core 21 at predetermined intervals in the circumferential direction. Further, the magnets 22 may be a ring magnet connected in the circumferential direction.
The stator 3 is housed in the housing 4. In the present example embodiment, the stator 3 has a tubular shape, and the rotor 2 is disposed radially inside. That is, the stator 3 is positioned so as to face the rotor 2 in the radial direction. The rotor 2 is positioned radially inside the stator 3 so as to be rotatable about the central axis P.
The stator 3 includes a stator core 31, a stator coil 33, and a bracket 34. In the present example embodiment, the stator core 31 has a cylindrical shape extending in the axial direction.
As illustrated in
As illustrated in
As shown in
Next, a method of manufacturing the stator core 31 having the above-described configuration will be described with reference to
As illustrated in
The central hole punching step described above is performed by press working. Since the central hole punching step is similar to a conventional method of manufacturing the stator core 31, the detailed description thereof is omitted.
Hereinafter, a method of manufacturing the stator core plate 32 having the protrusion 32d extending radially outward from the disk-shaped main body 32a in the method of manufacturing the stator core 31, and a mold thereof will be described in detail. The method of manufacturing the stator core plate 32 includes a protrusion forming step (step S2) and a main body forming step (step S3).
In the steel sheet 40 in which the central hole 40a and the rectangular holes 40b are formed as described above, the plurality of protrusions 32d are formed on the outer peripheral side of the central hole 40a. In the step of forming the protrusion 32d, in the steel sheet 40, a predetermined position on the concentric circle of the central hole 40a is punched in a shape including at least a portion of an outer shape X of the protrusion 32d. As a result, at least a portion of the outer shape X of the protrusion 32d extending radially outward is formed in the steel sheet 40. Further, the through hole 32e for attaching the stator core 31 is punched out on the radially inner side of the formed protrusion 32d. The step of forming at least a portion of the outer shape X of the protrusion 32d by punching a portion of the steel sheet 40 in a shape including at least a portion of the outer shape X of the protrusion 32d is the protrusion forming step shown in
As illustrated in
As illustrated in
As illustrated in
Next, as illustrated in
After the rotor core plate punching step, a plurality of slots 40c are punched around the central hole 40a in order to form a plurality of tooth portions 32c surrounding the central hole 40a in which the rotor core plate 23 has been punched. This step is a slot punching step shown in
The rotor core plate punching step and the slot punching step described above are performed by press working. Since the rotor core plate punching step and the slot punching step are similar to the conventional method of manufacturing the stator core 31, the detailed description thereof is omitted.
Next, as illustrated in
The punching in the main body forming step is performed by press working using a main body punch W2a and a main body die W2b. In the main body forming step, the steel sheet 40 is punched by the main body punch W2a and the main body die W2b such that an outer shape Y other than the portion punched out by the protrusion die W1b and the protrusion punch W1a in the outer shape of the stator core plate 32 is continuous with the outer shape X of the protrusion 32d formed in the steel sheet 40.
As illustrated in
As described above, since the recessed portion 32f is formed in advance at the portion where the outer shape X of the protrusion 32d and the outer shape Y of the main body 32a are connected in the protrusion forming step, a joint between the outer shape X of the protrusion 32d and the outer shape Y of the main body 32a is not formed in the stator core plate 32. Therefore, the stator core plate 32 can be formed in two steps, that is, the protrusion forming step of punching the shape including the outer shape X of the protrusion 32d, and the main body forming step of punching only the outer shape Y of the main body 32a. This makes it possible to prevent plastic deformation of the protrusion 32d in the manufacturing process of the stator core plate 32.
In addition, in the main body forming step, a portion other than the protrusion 32d of the stator core plate 32 punched by the main body punch W2a is pressed down while being in contact with the main body die W2b. That is, the main body die W2b and the main body punch W2a do not contact the protrusion 32d formed in the protrusion forming step in the steel sheet 40.
As described above, in the main body forming step, since the portion other than the protrusion 32d formed by the protrusion punch W1a and the protrusion die W1b is punched by the main body punch W2a and the main body die W2b, a punching stress due to the punching of the main body 32a and an external force due to the contact with the mold for punching the main body 32a are not generated in the protrusion 32d. This makes it possible to prevent plastic deformation of the protrusion 32d in the manufacturing process of the stator core plate 32.
As illustrated in
In the stator core plate 32 formed in this manner, the arrangement in the thickness direction of the fracture surface Fp1 and the shear surface Sp1 in at least a portion of the outer edge of the protrusion 32d is different from the arrangement in the thickness direction of the fracture surface Fp2 and the shear surface Sp2 in the outer edge of the main body 32a. That is, in the stator core plate 32, since the stator core plate 32 is formed in two steps, that is, the step of punching the shape including the outer shape X of the protrusion 32d and the step of punching the shape of the main body 32a, the punching stress due to the punching of the main body 32a and the external force due to the contact with the main body punch W2a and the main body die W2b for punching the main body 32a are not generated in the protrusion 32d. This makes it possible to prevent plastic deformation of the protrusion 32d of the stator core plate 32.
As described above, the method of manufacturing the stator core plate 32 having the protrusion 32d extending radially outward from the disk-shaped main body 32a includes the protrusion forming step of forming at least a portion of the outer shape X of the protrusion 32d by punching a portion of the steel sheet 40 in a shape including at least a portion of the outer shape X of the protrusion 32d, and the main body forming step of forming the main body 32a by punching the steel sheet 40 in a shape including the outer shape Y continuous with the outer shape X of the protrusion 32d formed on the steel sheet 40.
With such a configuration, since the protrusion 32d is punched in the protrusion forming step which is a pre-step of the main body forming step of forming the main body 32a, the punching stress due to the punching of the main body 32a and the external force due to the contact with the mold for punching the main body 32a are not generated in the protrusion 32d. This makes it possible to prevent plastic deformation of the protrusion 32d without forming a space for reducing magnetic flux density in the main body 32a.
Thereafter, the stator core plate 32 having the plurality of protrusions 32d and the plurality of tooth portions 32c formed by the method of manufacturing the stator core plate 32 is sequentially formed by the punching, and is stacked in the thickness direction. The stacked stator core plates 32 are caulked or welded to obtain the stator core 31 as illustrated in
Although the example embodiments of the present disclosure have been described above, the above-described example embodiments are merely examples for carrying out the present disclosure. Therefore, the example embodiments are not limited to the above-described example embodiments, and the above-described example embodiments can be appropriately modified and implemented within a range that does not deviate from the gist thereof.
In the above example embodiments, in the main body forming step, the stator core plate 32 formed by the punching is laminated to obtain the stator core 31. However, in addition to the punching, the stator core plate 32 may be formed by so-called pushback processing in which the punched portion is returned to an original position after being punched in the thickness direction in the shape of the stator core plate 32.
As illustrated in
As illustrated in
Thereafter, as illustrated in
Here, the step of forming the main body 32a by the pushback processing as described above corresponds to the pushback step.
As described above, in the main body forming step in the method of manufacturing the stator core plate 32, the main body 32a may be formed by the pushback processing in addition to the punching. By molding the stator core plate 32 by the pushback processing, generation of residual stress and residual strain due to processing in the main body 32a is suppressed. As described above, in the method of manufacturing the stator core plate 32, regardless of the method of processing the main body 32a, the punching stress due to the punching of the main body 32a and the external force due to the contact with the mold for punching the main body 32a are not generated in the protrusion 32d. This makes it possible to prevent plastic deformation of the protrusion 32d in the manufacturing process of the stator core plate 32.
In the above example embodiments, the motor is a so-called permanent magnet motor. In the permanent magnet motor, the rotor 2 has the magnet 22. However, the motor 1 may be a motor without the magnet 22, such as an induction machine, a reluctance motor, a switched reluctance motor, or a winding field type motor.
In the above example embodiments, the method of manufacturing the stator core 31 of the motor 1 has been described, but the present disclosure is not limited thereto, and the manufacturing method of the above example embodiments may be applied when a structure having a laminate of the steel sheets 40 is manufactured.
The present disclosure is applicable to a method of manufacturing the stator core plate 32 having the protrusion 32d extending radially outward from the plate disk-shaped main body 32a.
Features of the above-described preferred example embodiments and the modifications thereof may be combined appropriately as long as no conflict arises.
While example embodiments of the present disclosure have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the present disclosure. The scope of the present disclosure, therefore, is to be determined solely by the following claims.
Number | Date | Country | Kind |
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2019-063586 | Mar 2019 | JP | national |
This is a U.S. national stage of application No. PCT/JP2020/003708, filed on Jan. 31, 2020, and priority under 35 U.S.C. § 119(a) and 35 U.S.C. § 365(b) is claimed from Japanese Patent Application No. 2019-063586, filed on Mar. 28, 2019, the entire disclosures of which are hereby incorporated herein by reference.
Filing Document | Filing Date | Country | Kind |
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PCT/JP2020/003708 | 1/31/2020 | WO | 00 |