JP3550639B2 - Manufacturing method of coil core - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method of manufacturing a coil core for series winding suitable as, for example, a solenoid for a micro relay mounted on a board, and in particular, a series winding coil having a smooth peripheral surface capable of reducing a wire breakage rate during winding work. The present invention relates to a method for manufacturing a coil iron core.
[0002]
[Prior art]
In recent years, in order to reduce the thickness of electronic component mounting boards, development of ultra-compact board mounting relays having a height of about 1 to 2 mm has been promoted. Conventionally, the solenoid of this type of small relay employs a configuration in which a spool is placed on a rod-shaped iron core and a winding is wound on the spool, but in this case, the thickness of the spool, which is electromagnetically meaningless, is used. Only the height of the whole product will increase. Therefore, it is desired to employ a series-wound coil in which a winding is directly applied to an iron core without using a spool.
[0003]
An important point as a coil core for this kind of series-wound coil is that the peripheral surface is smooth over its entire length and there are no sharp projections or the like. The reason is that, for example, since an extremely thin electric wire having a diameter of about 20 μm is used, the probability of occurrence of winding breakage increases during winding work by an automatic winding machine. However, it is not easy to manufacture such a bar-shaped iron core from a thin sheet of pure iron or silicon steel sheet (for example, about 0.6 mm) as a material by a simple punching process.
[0004]
One example of a conventional method for manufacturing a coil core is shown in FIG. Note that this drawing schematically shows a cross section of a raw material plate (for example, a pure iron plate having a thickness of 0.6 mm) which is being processed, which is cut along a plane perpendicular to the axis of the rod-shaped iron core. First, in the pre-punching step shown in FIG. 7A, pre-punching processing is performed on both sides of the rod-shaped expected position 100 on the material plate to form pre-punch holes 101 and 102. Subsequently, in a shearing process shown in FIG. 4B, in order to smooth both side surfaces of the rod-shaped portion to be the iron core, both side edges of the rod-shaped core expected position 100 sandwiched between the preliminary punched holes 101 and 102 are formed. Is subjected to shaving. In this state, a bar-shaped portion to be an iron core (corresponding to the expected bar-shaped iron core position 100) is connected to the blank by a connecting bar (not shown). Subsequently, in the corner processing step shown in FIG. 4C, the four twills 100a to 100d of the rod-shaped portions having a rectangular cross section obtained in the previous step are rounded by press working. Subsequently, in a shearing process shown in FIG. 5D, a connecting bar (not shown) is cut by a shearing process to complete the bar-shaped core 103 as an individual piece separated from the material plate.
[0005]
[Problems to be solved by the invention]
However, in the conventional iron core manufacturing method shown in FIGS. 7A to 7D, in the shearing process shown in FIG. Since the shaving process is performed in a short period of time over 0.6 mm), even after the shaving process, the breaks left on both side surfaces 100c and 100d of the rod-shaped portion without being completely sheared over a considerable width. The cross section is exposed. This fractured surface has a severely rough surface and is left as it is on both side surfaces 103a and 103b of the rod-shaped iron core 103 as a final product, which causes wire breakage when winding around the iron core.
[0006]
The present invention has been made by paying attention to the above problems in the conventional method of manufacturing a coil core, and an object of the present invention is to provide a method of manufacturing an iron core that can reduce the occurrence of wire breakage during winding work. To provide.
[ 0007 ]
[Means for Solving the Problems]
The invention according to claim 1 of this application is a method for manufacturing a rod-shaped coil core having a rectangular cross section by punching a metal plate as a raw material by pressing.
Preliminary punching step of performing rectangular punching on both sides of the area where the metal core rod is to be formed, leaving a bar-shaped portion wider than the target coil core,
The upper and lower curved twill portions corresponding to the upper and lower corners, by crushing the flesh of both side edges along the longitudinal direction of the bar-shaped portion left unextracted in the preliminary punching step over substantially the entire length in the longitudinal direction, A corner processing step of simultaneously forming left and right ridges bulging toward the preliminary punching hole at an intermediate portion in the plate thickness direction,
An upper and lower crushing step of forming left and right thinned ridges by further crushing the left and right ridges formed by bulging from the left and right side surfaces of the rod-shaped portion in the corner processing step,
By shearing the thinned ridges formed on the left and right sides of the rod-shaped portion in the vertical crushing step, a shearing step of forming a rod-shaped portion corresponding to a target coil core,
And a method for manufacturing a coil core.
[0008]
The invention according to claim 2 of the present application is characterized in that the corner processing step and the up-and-down crushing step are completed in one step using the same mold. Manufacturing method.
[0009]
According to the present invention, the length of the shear surface in the thickness direction can be secured by the corner processing and the crushing processing for each twill portion of the iron core, and the thickness of the part to be sheared later is obtained by the corner processing and the crushing processing. It becomes thin, and the shearing surface length and surface roughness can be easily ensured in shearing processing such as shaving processing.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[0011]
One embodiment (hereinafter, referred to as a first embodiment) of a method for manufacturing a coil core according to the present invention is shown in FIGS. 1 (a) to 1 (d). As in the description of the conventional example, this drawing shows a cross section obtained by cutting a material plate (for example, a pure iron plate having a thickness of 0.6 mm) in the middle of processing along a plane orthogonal to the axis of the planned rod-shaped core. It is shown schematically. First, in the pre-punching step shown in FIG. 3A, pre-punching is performed on both sides of the bar-shaped iron core expected position 1 on the material plate to form pre-punching holes 2 and 3. In this state, the rod-shaped core core expected position 1 on the material plate is connected to the material plate by a connecting bar (not shown).
[0012]
Subsequently, in the corner processing step shown in FIG. 3B, the rod-shaped core core expected position to be interposed between the preliminary punched holes 2 and 3 in order to round the four twill portions of the rod-shaped portion 1a having a rectangular cross section to be an iron core. A curved surface 4a, 4b, 4c, 4d having a predetermined curvature (for example, a curvature of about 0.1 mm) and a smooth surface is provided on the upper and lower sides of the both side edges of 1 by press working from above and below. In addition, the material sandwiched between the upper and lower press dies moves to the left and right sides along the horizontal pressing surface of the press dies along with the press work from above and below performed to form the curved surface portions 4a to 4d. As a result, left and right protruding portions 5a and 5b are formed on both side surfaces of the rod-shaped portion 1a to be the iron core so as to protrude horizontally in the drawing.
[0013]
Subsequently, in a vertical crushing step shown in FIG. 5C, the left and right protrusions 5a and 5b formed in the previous step shown in FIG. The thickness D1 of the protrusions 5a and 5b is further reduced. As a specific example, when the plate pressure D0 of the material plate is set to 0.6 mm, the thickness D1 of the protrusion is reduced to about 0.1 mm. Note that the vertical surfaces 6a and 6b formed on both side surfaces of the bar-shaped portion 1a in the vertical crushing process are smooth shearing surfaces.
[0014]
Subsequently, in a shearing step shown in FIG. 4D, the roots of the left and right protrusions 5a and 5b are cut by vertical shearing to separate the rod-shaped portion 1a to be an iron core from the material plate. Complete the desired coil core.
[0015]
When observing the peripheral surface properties of the coil core obtained in this manner, the upper and lower surfaces are the front and back surfaces of the material plate, so that it is naturally smooth, and the four twill portions are pressed by pressing. Since the curved surface portions 4a to 4d are formed, the surface is smooth. In addition, as for the left and right side surfaces, the upper half portion in the figure is the vertical surfaces 6a and 6b where the shear surfaces generated in the vertical crushing step (d) are exposed, so that these are also smooth. Further, in the lower half portion in the figure where the left and right protruding portions 5a and 5b have been cut and removed, a thickness portion of only about 0.1 mm has been cut off by shearing. The surface becomes a smooth shear surface over the entire surface. Even if the fractured surface is left, it is only a small area that can be visually recognized only as an extremely thin line, and as a whole the surface roughness in practical use as a coil core for direct winding is sufficient. Is pleased. Therefore, the peripheral surface of the coil core obtained in this way is extremely smooth, and the wire breakage rate during winding work can be significantly reduced. In addition, according to this method, (1) there is no need to separate the corner processing for each twill portion of the iron core and the shaving process for securing the surface roughness of the sheared surface into separate processes, and (2) the material yield is reduced. In addition, there are also advantages in that the connecting bar can be formed at a location near the coil winding portion, and (3) processing can be performed in the same process, thereby reducing processing costs and management costs.
[0016]
Another embodiment (hereinafter, referred to as a second embodiment) of a method for manufacturing a coil core according to the present invention is shown in FIGS. 2 (a) to 2 (c). The feature of the second embodiment is that the corner processing step (FIG. 1B) and the vertical crushing step (FIG. 1C) in the method of the first embodiment are simultaneously performed in one step. It is in the point. 1A to 1D are denoted by the same reference numerals.
[0017]
That is, in the corner processing and the up / down crushing step shown in FIG. 2B, the two steps shown in FIGS. 1B and 1C are completed in one step using a single mold. . Therefore, according to this method, the number of steps can be reduced by that much as compared with the method shown in FIG.
[0018]
【Example】
Hereinafter, an embodiment of a method of manufacturing a coil core according to the present invention will be described in more detail with reference to FIGS. In this manufacturing method, a strip-shaped pure iron plate or a silicon steel plate having a thickness of 0.6 mm is used as the material plate 7.
[0019]
First, in the first step, as shown in FIG. 3A, a rod-shaped portion 8 to be an iron core is positioned on a raw material plate 7, and rectangular punched holes H1 are formed on both sides of the rod-shaped portion 8 so as to sandwich the rod-shaped portion 8. , H2 (shown by hatching in the figure).
[0020]
In the subsequent step, as shown in FIG. 3B, the punching holes H3, H4 are separated from the punching holes H1, H2 formed before and after by a small linear gap corresponding to the width of the connecting bar. By forming the holes H5 and H6, four connecting bars 9a to 9d for holding the rod portion 8 on the material plate 7 are formed.
[0021]
In the subsequent step, as shown in FIG. 3C, press processing from above and below (corresponding to the step shown in FIG. 2B) is performed on both side edges 10a and 10b of the rod-shaped portion 8 so as to perform both corner processing and vertical pressing processing. ), The chamfering process (corresponding to 4a to 4d in FIG. 2) into the four twill portions of the rod-shaped portion 8 and the crushing process of the left and right protruding portions (corresponding to 5a and 5b in FIG. 2) are simultaneously performed. Do. At this time, the thickness of the portion crushed by the crushing process is reduced to about 0.1 mm.
[0022]
In the subsequent step, as shown in FIG. 4A, large rectangular punched holes H <b> 7 and H <b> 8 are formed at both ends in the axial direction of the rod 8 in order to regulate both ends of the rod 8. These punched holes H7, H8 are set to have sizes that are partially adjacent to the four holes H3, H4, H5, H6 forming the four connecting bars 9a to 9d.
[0023]
In the subsequent step, as shown in FIG. 4B, the boundary between the punched hole H7 and the punched holes H3 and H5, and the boundary between the punched hole H8 and the punched holes H4 and H6 are cut off. Are grown into the punched holes H9 and H10 having a larger area, so that the predetermined lengths at both ends of the rod-shaped portion 8 to be the iron core are free ends for bending in the future.
[0024]
In the subsequent step, as shown in FIG. 4 (c), the free end formed in the previous step is bent at a substantially right angle in a direction perpendicular to the plane of the drawing, so that both ends of the rod-shaped portion to be the iron core are formed. The bent portions 8a and 8b are formed. Thereby, the rod-shaped portion 8 to be the iron core has a substantially U-shape or C-shape as a whole.
[0025]
In a subsequent step, as shown in FIG. 5A, both side edges 10a and 10b of the rod-shaped portion 8 previously thinned to about 0.1 mm in the step of FIG. Are separated by shearing (corresponding to the step of FIG. 2C) to complete the coil core 11 shown in FIG. 5B.
[0026]
When observing the peripheral surface properties of the coil core 11 manufactured as described above, the upper and lower surfaces A1 and A2 are not only smooth because the upper and lower surfaces A1 and A2 are the front and back surfaces of the material plate 7, but also the four twill portions B1. The surfaces B4 to B4 are smooth because they are curved portions formed by press working. In addition, as for the left and right side surfaces C1 and C2, a substantially upper half portion in the figure is a vertical surface where a sheared surface generated by press working is exposed, so that this is also smooth. Further, in the lower half portion in the figure, a portion having a thickness of only about 0.1 mm was cut off by shearing, so that the cut mark has a smooth shear surface over almost the entire width. Even if the fractured surface is left, it is only a small area that can be visually recognized only as an extremely thin line, and as a whole the surface roughness in practical use as a coil core for direct winding is sufficient. Is pleased. Therefore, the peripheral surface of the coil core obtained in this way is extremely smooth, and the wire breakage rate during winding work can be significantly reduced.
[0027]
Finally, the lateral properties of the rod-shaped iron core according to the conventional method and the lateral properties of the rod-shaped iron core according to the method of the present invention are shown in FIGS. As is apparent from these photographs, it will be easily understood that the side surface properties of the iron core according to the method of the present invention are clearly superior to those of the conventional method.
[0028]
【The invention's effect】
As is apparent from the above description, according to the present invention, the length of the shear surface in the thickness direction can be ensured by the corner processing and the crushing processing on each of the twill portions of the iron core, and the thickness of the portion to be sheared later is also obtained. Is thinned by the corner processing and the crushing processing, and the shearing length such as shaving processing and the surface roughness can be easily secured. Therefore, it is possible to manufacture a straight-wound coil core that can reduce the incidence of wire breakage during winding work.
[Brief description of the drawings]
FIG. 1 is a process chart showing a first embodiment of a method according to the present invention.
FIG. 2 is a process chart showing a second embodiment of the method according to the present invention.
FIG. 3 is a more detailed flow chart showing one embodiment of the method according to the present invention.
FIG. 4 is a more detailed flow chart showing one embodiment of the method according to the present invention.
FIG. 5 is a more detailed flow chart showing one embodiment of the method according to the present invention.
FIG. 6 is a photograph substituted for a drawing, showing a comparison between the side surface properties of a bar-shaped iron core according to a conventional method and the side properties of a bar-shaped iron core according to the method of the present invention.
FIG. 7 is a process chart showing a conventional method.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Expected position of rod-shaped core on material plate 1a Bar-shaped portion to be iron core 2, 3 Pre-drilled holes 4a to 4d Curved surface 5a, 5b Projection 6a, 6b Vertical surface 7 Material plate 8 Rod-shaped portion 8a, 8b to be iron core Both ends 9a to 9d of the bar-shaped portion Connecting bars 10a, 10b Both side edges 11 of the bar-shaped portion Coil cores H1 to H11 Punched hole A1 Upper surface of coil core A2 Lower surface B1 to B4 of coil core C1 and C2 of coil core side

Claims (2)

A method of manufacturing a rod-shaped coil core having a rectangular cross section by punching a metal plate as a material by press working,
Preliminary punching step of performing rectangular punching on both sides of the area where the metal core rod is to be formed, leaving a bar-shaped portion wider than the target coil core,
The upper and lower curved twill portions corresponding to the upper and lower corners, by crushing the flesh of both side edges along the longitudinal direction of the bar-shaped portion left unextracted in the preliminary punching step over substantially the entire length in the longitudinal direction, A corner processing step of simultaneously forming left and right ridges bulging toward the preliminary punching hole at an intermediate portion in the plate thickness direction,
An upper and lower crushing step of forming left and right thinned ridges by further crushing the left and right ridges formed by bulging from the left and right side surfaces of the rod-shaped portion in the corner processing step,
By shearing the thinned ridges formed on the left and right sides of the rod-shaped portion in the vertical crushing step, a shearing step of forming a rod-shaped portion corresponding to a target coil core,
A method for manufacturing a coil core, comprising: The method for manufacturing a coil core according to claim 1, wherein the corner processing step and the vertical crushing step are completed in one step using the same mold.

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