JP3307092B2 - Air core coil lead forming method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of molding a lead portion of an air-core coil used in an electronic circuit such as a tuner, and more specifically, two lead portions in the same direction from the center of the main body. The present invention relates to a method of forming a lead portion of an air-core coil, which is manufactured so as to protrude into a so-called center lead type air-core coil.

[0002]

2. Description of the Related Art FIG. 3 shows an example of a center lead type air core coil. The air-core coil 4 has two lead portions 42
And 43 are formed so that they protrude in the same direction from the center of the main body 41.

FIGS. 4 and 5 show examples of a conventional lead portion forming method for forming the lead portion of an air-core coil as described above.

In any of the lead forming methods, an air-core coil 4a having two leads 42 and 43 protruding in the same direction from the side of the main body 41 is used as the air core coil 4a before forming the lead. The air core coil 4a is held on a spindle 8 of the air core coil winding machine here.
Here, for forming the lead portion, a pair of forming claws 6 which are arranged below the spindle 8 and are opened and closed in directions in which the forming surfaces 61 at the tip end are in contact with each other and in the opposite direction are used. The one whose surface 61 is substantially orthogonal to the opening and closing direction is used.

In the lead part forming method shown in FIG. 4, two lead parts 4 of the air-core coil 4a on the spindle 8 as described above are used.
2 and 43 are pressed at once from the left and right with the pair of forming claws 6 as described above (FIGS. 4A and 4B).
43 is formed so as to protrude from the substantially central portion of the main body 41 in the same direction (FIG. 4C). Thereby, the center lead type air-core coil 4 is obtained.

However, in the above-described simple forming method, there is a problem that the two lead portions 42 and 43 are spread as shown in FIG. 4C due to the springback of the wire.

In order to insert such an air core coil 4 into, for example, a hole in a printed circuit board, it is necessary to hold the leads 42 and 43 correctly, so that both automatic insertion and manual insertion become difficult.

The lead forming method shown in FIG. 5 uses the two leads 4 in anticipation of the spread of the leads 42 and 43 in order to eliminate the spread of the leads 42 and 43 as described above.
This is a method of molding the components 2 and 43 separately.

First, one of the lead portions 42 of the air-core coil 4a on the spindle 8 is pressed from the left and right with the pair of forming claws 6 as described above. It is formed so as to protrude substantially from the center (FIGS. 5A to 5C). The lead 42 after this molding is shown in FIG.
As shown in FIG. 5, the spring backs to the right from the state at the time of molding (FIG. 5B).

Next, as shown in FIG.
a when the other lead 43 springs back after the subsequent molding step (see FIG. 5F).
Rotate to the extent that it aligns.

In this state, the other lead portion 43
Is pressed from the left and right with a pair of forming claws 6 so that the lead portion 43 protrudes from a substantially central portion of the main body portion 41 (FIGS. 5E and 5F). The lead portion 43 after this molding is
As shown in FIG. 5F, the spring backs to the left from the state at the time of molding (FIG. 5E). Thereby, the center lead type air-core coil 4 is obtained.

According to the molding method as shown in FIG. 5, the two lead portions 42 and 43 should be aligned. However, the lead portion 42,
Since the springback amount of 43 also varies, the lead 4
There still exists a problem that the tip positions of 2, 43 have large variations.

SUMMARY OF THE INVENTION Accordingly, it is a main object of the present invention to provide a method of forming a lead portion of an air-core coil which can reduce the variation in the springback amount of the lead portion and increase the lead portion forming accuracy.

[0014]

In order to achieve the above object, a method of forming a lead portion of an air-core coil according to the present invention comprises a pair of forming claws which are opened and closed in directions in which the forming surfaces at the tip portions match each other and in the opposite direction. The first lead portion of the air-core coil having the first and second lead portions projecting in the same direction from the side of the main body portion is used. Pressing with the forming claw, forming the lead portion so as to protrude from the substantially central portion of the main body portion.
And then rotating the air-core coil to such an extent that when the second lead springs back after the second forming step, it intersects the first lead at the root. And a second forming step of pressing the second lead portion of the air-core coil using the forming claw to form the lead portion so as to protrude from a substantially central portion of the main body portion, Next, a second rotation step of rotating the air-core coil so that the center line between the intersecting first and second lead portions is substantially parallel to the molding surface of the molding claw, and A step of pressing the first and second lead portions of the air-core coil simultaneously with the forming claws again to correct the two lead portions so as to be aligned with the center line.

[0015] The straightening step may be divided into a first straightening step for straightening one lead portion and a second straightening step for straightening the other lead portion.

[0016]

FIG. 1 is a process diagram showing an example of a method of forming a lead portion of an air-core coil according to the present invention. 4 and 5
The same reference numerals are given to the same or corresponding parts as in the conventional example, and the differences from the conventional example will be mainly described below.

In this embodiment, first, one (first) lead portion 42 of the air-core coil 4a on the spindle 8 is pressed from the left and right by the pair of forming claws 6 as described above. Then, the lead portion 42 is formed so as to protrude from a substantially central portion of the main body portion 41 (FIGS. 1A to 1C). This is the first
This is a molding step. The lead portion 42 after this molding is shown in FIG.
As shown in C, the spring backs to the right from the state at the time of molding (FIG. 1B).

Next, the air-core coil 4a is moved, for example, in a clockwise direction after the second forming step (FIG. 1E).
When the lead portion 43 springs back, it is rotated to the extent that it intersects the lead portion 42 at the root (see FIG. 1F) (FIG. 1D). This is the first rotation step. This rotation angle is slightly larger than that of FIG. 5D.

In this state, the other lead portion 43
Is pressed from the left and right with a pair of forming claws 6 to form the lead portion 43 so as to protrude from the substantially central portion of the main body portion 41 (FIG. 1E). This is the second molding step. As shown in FIG. 1F, the lead 43 after this molding springs back to the left from the state at the time of molding (FIG. 1E). At this time, as described above, both lead portions 42 and 43 intersect. 44 shows the center line.

Next, the air-core coil 4a is rotated, for example, in a counterclockwise direction so that the center line 44 between the intersecting leads 42, 43 is substantially parallel to the forming surface 61 of the forming claw 6. (FIG. 1G). This is the second rotation step.

In this state, the two lead portions 42 and 43 of the air core coil 4a are simultaneously pressed from the left and right with a pair of forming claws 6 so that the two lead portions 42 and 43 are aligned on the center line 44. (FIG. 1H, I). This is the correction process. Thus, a center lead type air core coil 4 as shown in FIG. 1I is obtained.

In this correction process, both lead portions 42, 43
The apparent springback becomes almost zero, thereby reducing the variation in the tip positions of the lead portions 42 and 43 without being affected by variations in the diameter and tension of the wire rod, thereby improving the accuracy of forming the lead portion. Can be enhanced.
This will be described in detail with reference to FIG.

FIG. 2 is an enlarged view showing before and after the lead portion correcting step in FIG. 1, and FIGS. 1A, 1B and 1D show FIGS.
I respectively. In FIG. 2, the spring back of the main body 41 of the air core coil 4a (that is, the main body 41
In this example, only the springback of the lead portion (lead portion 43 in this example) is described, ignoring that the diameter near the lead portion becomes slightly larger.

The above-described second rotation step (FIG. 1F to G)
When the air-core coil 4a is slightly rotated in the counterclockwise direction as shown by arrow A in step (f), the second molding step (FIG. 1E) is performed.
A point P bent slightly moves rightward as indicated by a two-dot chain line in FIG. 2A. The rotation angle at this time is
For example, a small value of about 5 degrees may be used.

In this state, when the lead portion 43 is pressed from the left and right with a pair of forming claws 6, the lead portion 43 is bent at a new point Q as shown by a solid line in FIG. 2B. 2
The lead portion 43 indicated by the dashed line is the same position as the lead portion 43 indicated by the dashed line in FIG. 2A. Since the air-core coil 4a is slightly rotated in the process of FIG. 2A, the new bending point Q is slightly shifted to the left from the previous bending point P.

Therefore, in the pressing step of FIG. 2B, when viewed in detail, the operation of straightening the point P, which has been bent in a U-shape, and the operation of bending the lead portion 43 at a new point Q are combined. Done.

Therefore, when the forming claw 6 is opened, the springback due to the extension of the point P moves to the left as shown by the two-dot chain line in FIG. Conversely, the springback due to bending of point Q goes to the right (because it tries to return to the original straight line at point Q), and both springbacks cancel each other out. Direction, and the combination of both springbacks is the lead 4 after the straightening process.
Springback of 3. Moreover, variations in the diameter, tension, etc. of the wire rod are equally effective for the springbacks at both the points P and Q. Even if these variations occur, they cancel each other out, and the variation in the combined springbacks is reduced.

When the springbacks of both points P and Q are combined as described above, the position of the tip of the lead portion 43 after correction hardly moves, as shown in FIG. 2D. That is, the lead portion 43 apparently has no springback.

Incidentally, the above-mentioned combined springback amount can be adjusted by how much the point Q is shifted from the point P, that is, by the angle between the point Q and the point P. According to an experiment, this angle is set to 5 degrees. When it was set to about, the combined springback amount could be minimized.

In FIG. 2, the lead portion 43 has been described as an example, but the lead portion 42 is completely the same. That is, since the lead portion 42 also enters the molding process in a state (FIG. 1G) slightly rotated clockwise from the state after the first molding process (FIG. 1C), the lead portion 42 in the correction process in FIG. The new fold point is slightly offset to the right from the fold point in the first forming step, and the springbacks at both points cancel each other out.

By the above-described operation, the apparent springback of the two lead portions 42 and 43 becomes almost zero after the straightening process, and thus, the wire springs are not affected by variations in the diameter and tension of the wire rod. Leads 42, 4
The variation in the position of the tip 3 can be reduced. That is, the variation in the amount of springback between the lead portions 42 and 43 can be reduced, and the molding accuracy of the lead portions can be increased.

As a result, when automatically inserting an air-core coil into a hole of a substrate such as a printed circuit board, conventionally, only the method of holding and inserting the lead portion of the air-core coil could be used.
In the air-core coil 4 formed by the above molding method, the lead portion 42,
Since the molding accuracy of 43 is improved, it becomes possible to insert the air core coil 4 while gripping the main body portion 41, thereby facilitating automatic insertion, and simplifying the mechanism of the chuck of the automatic insertion machine to reduce cost. It can be cheaper.

In hand insertion, the lead 42,
Since the molding accuracy of 43 is increased, the displacement between the positions of the lead portions 42 and 43 of the air-core coil 4 and the positions of the holes on the substrate is reduced, and insertion becomes easy.

In the example shown in FIG. 1, the two leads 42 and 43 are simultaneously corrected in one correction step (FIG. 1H). However, the two leads 42 and 43 are corrected in another correction step. May be. In this case, instead of the straightening step of FIG. 1H, one lead portion, for example, the lead portion 42 is
A first straightening step in which the lead portion 42 is pressed again to correct the lead portion 42 so as to be positioned on the center line 44;
And a second correction step of correcting the third position so as to be located on the center line 44. However, the two lead portions 42
If steps 43 and 43 are corrected at the same time, only one correction step is required, so that the steps can be simplified.

[0035]

Since the present invention is configured as described above, it has the following effects.

That is, according to the lead forming method of the first and second aspects, the apparent springback of the lead of the air-core coil becomes substantially zero after the straightening step, whereby the diameter and tension of the wire are reduced. Of the leads can be reduced without being affected by the variation of the lead portions. That is, the variation in the amount of springback of the lead portion can be reduced, and the accuracy of forming the lead portion can be increased. As a result, the automatic insertion and manual insertion of the air core coil into the substrate by this lead portion forming method can be facilitated.

Further, according to the lead portion forming method of the present invention, since only one correcting step is required, the steps can be simplified.

[Brief description of the drawings]

FIG. 1 is a process chart showing an example of a method for forming a lead portion of an air-core coil according to the present invention.

FIG. 2 is an enlarged view showing before and after a lead portion correcting step in FIG. 1;

3A and 3B are diagrams showing an example of a center lead type air-core coil, wherein FIG. 3A is a front view and FIG. 3B is a side view.

FIG. 4 is a process chart showing an example of a conventional method for forming a lead portion of an air-core coil.

FIG. 5 is a process chart showing another example of a conventional method of forming a lead portion of an air-core coil.

[Explanation of symbols]

 4, 4a Air-core coil 41 Main body 42 First lead 43 Second lead 44 Center line 6 Forming claw 61 Forming surface 8 Spindle

Continued on the front page (72) Inventor Soji Egawa 2-26-10 Tenjin, Nagaokakyo-shi, Kyoto Inside Murata Manufacturing Co., Ltd. (72) Inventor Masato Murata 2-26-10 Tenjin, Nagaokakyo-shi, Kyoto Murata Co., Ltd. (56) References JP-A-2-50411 (JP, A) JP-A-5-326789 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01F 41/00- 41/10 H01F 17/00-17/08

Claims (2)

(57) [Claims] 1. A pair of molding claws which are opened and closed in a direction in which molding surfaces of the distal end portions are aligned with each other and in a direction opposite thereto, and which have molding surfaces substantially orthogonal to the opening and closing direction. The first lead portion of the air-core coil from which the first and second lead portions protrude in the same direction is pressed by the forming claw to form the lead portion so as to protrude from the substantially central portion of the main body. A first forming step, and then rotating the air-core coil to such an extent that when the second lead section springs back after the second forming step, it intersects the first lead section at the root. A second forming step of pressing the second lead portion of the air-core coil using the forming claw to form the lead portion so as to protrude from a substantially central portion of the main body portion; And then the air core coil,
A second rotating step of rotating the center line between the intersecting first and second lead portions so as to be substantially parallel to the molding surface of the molding claw; A pressing step of simultaneously pressing the second lead portion again with the forming claw to correct the two lead portions so as to be aligned with the center line. 2. A pair of molding claws which are opened and closed in directions in which the molding surfaces of the distal end portions are aligned with each other and in the opposite direction, and whose molding surfaces are substantially orthogonal to the opening and closing direction. The first lead portion of the air-core coil from which the first and second lead portions protrude in the same direction is pressed by the forming claw to form the lead portion so as to protrude from the substantially central portion of the main body. A first forming step, and then rotating the air-core coil to such an extent that when the second lead section springs back after the second forming step, it intersects the first lead section at the root. A second forming step of pressing the second lead portion of the air-core coil using the forming claw to form the lead portion so as to protrude from a substantially central portion of the main body portion; And then the air core coil,
A center line between the intersecting first and second leads
Is rotated substantially parallel to the molding surface of the molding claw.
A second rotation step, and a first correction step of pressing one of the lead portions of the air-core coil again with the forming claws to correct the lead portion so as to be positioned on the center line;
A second correction step of pressing the other lead portion of the air core coil again with the molding claw to correct the lead portion so as to be positioned on the center line. Lead molding method.