JP2843760B2 - Surface mount type coil parts - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface mount type coil component such as a noise filter and a choke coil which is surface mounted on a circuit board of an electronic device. It relates to a structure for solving the cause of failure.

[0002]

2. Description of the Related Art In recent years, there has been a strong demand for smaller and higher-performance electronic devices and the like, and accordingly, transformers and noise filters for coil components which occupy a relatively large floor area in electronic components mounted on an electronic circuit board. Also, a surface-mount type coil component having a structure using a drum-type core suitable for surface mounting while reducing the size and thickness of choke coils and the like has been developed.

For example, in a high-frequency choke coil used in a DC / DC converter, an inverter and the like,
Generally, a drum-shaped core made of a magnetic material having a shape in which a flange portion is provided at each of the upper and lower ends of a columnar coil winding shaft portion disposed in a vertical direction is adhered and fixed to a pedestal, and wound around the coil winding shaft portion. Is often used in a surface mounting type having a structure in which is wound and soldered to a lead terminal mounted on a pedestal.

FIG. 8 is a perspective view showing a typical example of the structure of the above-mentioned conventional surface mount type high frequency choke coil.

In FIG. 1, a high-frequency choke coil 10
Has a drum-type core 3 on which a winding 4 is wound, and a pedestal 6 on which lead terminals 5a... Which are bonded and fixed to the drum-type core 3 and are conductively connected to the winding are implanted. .

In the conventional high-frequency choke coil 10, the lead terminals 5a, 5b,... Protrude radially from the pedestal side surface 7 and are bent into an S-shape, so that the tips are located at substantially the same height as the pedestal bottom surface. In the state where it is placed on the mounting board surface, there is no flapping of parts and soldering is reliable.
It is easy to do.

To manufacture the high-frequency choke coil 10, first, a flange 2b below the drum core 3 is bonded and fixed to the upper surface of the pedestal 6 substantially at the center thereof with an adhesive or the like.
a. After winding the end of the winding 4 around the base 9 of one of the lead terminals (5a), the winding shaft 1 of the drum core 3
, And finally the other lead terminals (5c) are wound by an automatic winding machine, and then the lead terminals 5a are completed by soldering and dipping together the portions.

Here, since the above-mentioned drum type core 1 generally has a high resistivity, ferrite (nickel-zinc-based ferrite, manganese-zinc-based ferrite, etc.) which is an oxide magnetic material widely used as a high-frequency core material is sintered. The one formed by binding is usually used.

The pedestal 6 is made by injection molding a synthetic resin such as PBT, PET, nylon or the like.

The high-frequency choke coil 10
When mounting a small surface-mounted electronic component such as described above on a mounting board, an automatic mounting apparatus is generally used at present.

At the time of mounting the surface mount type coil component, a mechanism for positioning the automatic mounting apparatus in a horizontal direction as shown in a plan view of FIG. The chuck portions 11a to 11d sandwich the pedestal 6 side surface of the high-frequency choke coil 10 from all sides and give a horizontal direction to the mounting substrate accurately.

By the above operation, the surface mount type coil components including the high frequency choke coil 10 are correctly mounted on the mounting board.

[0013]

However, the mounting of the coil component by the automatic mounting apparatus requires the mechanical chuck 11
a ... comes into contact with the side surface of the coil
In the lead terminal structure protruding from the side surface in the radial direction (outside) like the above-described conventional high-frequency choke coil 10, the mechanical chuck portion 11 sandwiching the side on which the lead terminals 5a.
a and 11b sandwich the lead terminals 5a, and there is a problem that a load is applied to the lead terminals 5a and the windings 4 and the lead terminals 5a are bent. In such a state, the components may cause flapping or disconnection.

As shown in FIG. 9, the pedestal 6 having a square or rectangular planar shape has a large mounting width X in the direction in which the lead terminals 5a... Is disadvantageous.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has been made to reduce the floor area of a surface mount type coil component having a shape in which a drum type core is adhered and fixed to a pedestal on which lead terminals are implanted, and to achieve automatic mounting. A pedestal structure and a terminal structure for solving the problem with the lead terminal are provided.

[0016]

According to the present invention, there is provided a drum-type core having a winding wound thereon, and a pedestal having a lead terminal for bonding and fixing the drum-type core and having a lead terminal electrically conductively connected to the winding. In the surface mount type coil component, the edge of the bottom surface side on the side where the lead terminals on the side of the pedestal are exposed is cut off obliquely, and the dedicated terminal is attached to the obliquely formed surface and the outermost edge of the pedestal The terminal protruding obliquely downward so that it does not protrude beyond the wire, and the lead terminal that is connected and integrated inside the pedestal and the dedicated terminal for lashing is mounted on the mounting board of the automatic mounting device on the side of the pedestal. The object is achieved by providing a surface-mount type coil component characterized by being arranged so as not to protrude from parallel opposing positioning surfaces for sandwiching a mechanical chuck portion for performing positioning. It is intended to formed.

[0017]

According to the present invention, since the edge of the bottom surface on the side where the lead terminals on the side of the pedestal are exposed is cut off obliquely, the protruding portions of the barbed terminals and the lead terminals and the bottom surface of the pedestal are removed. The occupied floor area occupied by the cut portion is reduced, and the mounting density can be increased.

In addition, a structure may be provided in which a dedicated terminal for shaving the winding is planted obliquely downward so as not to protrude beyond the outermost line of the pedestal on the oblique molding surface. Will be possible.

Further, since it is not necessary to wind and connect the windings to the lead terminals, the shape and the implanted shape with respect to the pedestal can be freely designed except that they are exposed at the bottom of the pedestal.

Therefore, the lead terminals do not protrude outside from the parallel opposing positioning surfaces for sandwiching the mechanical chuck portion for performing positioning on the mounting board by the automatic mounting device on the pedestal. Does not contact terminals.

For example, the mechanism is configured such that it is exposed from the inside of the pedestal to the pedestal bottom surface in a state of being substantially in close contact with the pedestal, bent, sandwiched by the positioning surface, and does not protrude from the positioning surface. When the chuck portion sandwiches the positioning surface of the protrusion on the side surface of the pedestal, the mechanical chuck portion does not touch and bend the lead terminal.

Further, as a method of connecting the windings by winding, the lead terminals are connected to dedicated terminals which protrude independently from the pedestal. Does not directly affect terminals.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described in detail with reference to the drawings. The same reference numerals are used for members having the same shape.

FIG. 1 is a perspective view for explaining a high-frequency choke coil as a typical example of a surface-mount type coil component according to the present invention, and FIG. 2 is a plan view of a base of the high-frequency choke coil. FIG. 3 is a front view of the pedestal.
FIG. 4 is a partially enlarged longitudinal sectional view taken along line AA in the plan view. FIG. 5 shows another embodiment relating to the arrangement of the special-use terminals, and FIGS. 6 and 7 are plan views showing other embodiments of the pedestal.

1 and 2, a high-frequency choke coil 20 comprises a drum core 3 on which a winding 4 is wound, and a lead terminal for bonding and fixing the drum core 3 and electrically connecting to the winding 4. And a pedestal 26 on which the pedestal 25 is implanted.
The edge 26b on the bottom surface side on the side where the lead terminal 25a is exposed is cut off obliquely, and the dedicated terminal 27 protrudes beyond the outermost contour line f of the pedestal on the oblique forming surface 28. In addition, the lead terminal 25, which protrudes obliquely downward so as not to be bent and is connected to the dedicated terminal 27 and integrated inside the pedestal, positions the side of the pedestal to the mounting board of the automatic mounting apparatus. Mechanical chuck 11a ...
Are arranged so as not to protrude from the parallel opposing positioning surfaces 21 for being sandwiched.

More specifically, the drum-type core 3 is formed by pressure-molding and sintering a general ferrite powder as a magnetic material, and has flanges 2a, 2b at both ends.
Is provided, and a center portion around which the winding is wound is the same as in the related art.

The ferrite material of the drum-type core 3 is an oxide magnetic material, which has a relatively high resistance and a small high-frequency loss, and is widely used especially as a high-frequency magnetic material. There are types such as nickel cobalt ferrite, nickel zinc ferrite, and manganese zinc ferrite.

The pedestal 26 is made of a synthetic resin, and is formed by injection molding a thermoplastic resin such as polybutylene terephthalate (PBT) or polyethylene terephthalate (PET), or a thermosetting resin such as melamine resin or phenol resin. . A fitting recess is provided on the upper surface of the pedestal 26 so that the lower flange 2b of the drum core 3 is correctly positioned at the center of the pedestal.
The circular recess 15 is formed not only on the entire surface but also on the peripheral portion to improve the seating and stabilize the adhesive fixation.

The winding 4 is an insulated conductor such as an enamel-coated conductor or a polyurethane-coated conductor. The dedicated terminal 27 and the lead terminal 25 are made of iron or phosphor bronze such as Kovar or 42 alloy, or copper such as copper containing iron. The system metal is integrally formed and plated with solder, and is connected inside the pedestal 26 as shown by the broken line in FIG.

The two right and left dedicated terminals 27 in FIGS. 2 and 3 are terminals only for removing the ends of the windings 4 and soldering, regardless of the conductive connection with the mounting board. As is clear from FIG. 4, the side surface 26 of the pedestal 26 does not protrude from the outermost line f of the positioning surface 21 to the outside.
a projecting obliquely downward from the oblique forming surface 28a, the mechanical chucks 11a do not touch.

Here, the oblique forming surface 28 on the pedestal side surface 26 is formed at an angle of 45 degrees with respect to the pedestal bottom surface 29, and the terminal 27 dedicated to lashing is configured to project perpendicularly from the oblique forming surface 28. Would be appropriate. The oblique forming surface 28 is not limited to a flat surface and may be an R shape.

As shown in FIGS. 2 and 4, the lead terminal 25 is exposed from the inside of the pedestal 26 to the pedestal bottom surface 29 in a substantially flat state (25a), and is bent to form the positioning surface. 21 so as not to protrude from the positioning surface 21.

Therefore, the mechanical chuck portions 11a, 11a
b is the lead terminal 25 when the positioning surface 21 is sandwiched.
Do not touch it and bend it.

The dedicated terminal 27 and the lead terminal 25 do not protrude in the horizontal direction with respect to the mounting substrate as in the prior art, and the edge 26b on the bottom side on the side of the pedestal side surface 26a where the lead terminal 25 is exposed. Is obliquely cut off, the mounting width becomes X ', and it is clear that the occupied floor area becomes extremely small.

Since the end of the lead terminal 25 is bent upward, there is an advantage that the quality of soldering at the time of mounting can be determined by visually checking the solder state of the bent portion.

It should be noted that, even in a transformer other than a high-frequency choke coil, for example, which requires four terminals, a dedicated terminal 2
It goes without saying that the same advantages as described above can be obtained by arranging the terminals in which the lead 7 and the lead terminal 25 are integrated on four sides inside the pedestal. In this case, it would be better to make the shape slightly rounded so that each terminal does not touch inside the pedestal. Alternatively, it is considered that providing a terminal with a step inside the pedestal is also effective for preventing contact.

It should be noted that the positional relationship between each of the dedicated shank terminals 27 and the lead terminals 25 is not limited to the left-right symmetric type as shown in FIG. 2 but may be the rotationally symmetric type as shown in FIG. Of course, the planar shape of the pedestal 26 is not limited to a quadrangle, but may be, for example, an octagon as shown in FIG. 6 or a circular shape as shown in FIG.

[0038]

Since the surface mount type coil component according to the present invention is configured as described above, it has the following effects.

(1) An excellent effect that the causes of defects such as product flapping and disconnection due to the bending of the terminal due to the mechanical chuck portion at the time of automatic mounting on the mounting board can be fundamentally eliminated and the product yield can be improved. Have.

(2) There is an excellent effect that the board mounting density can be improved.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating a high-frequency choke coil as a typical example of a surface-mounted coil component according to the present invention.

FIG. 2 is a plan view of a base of the high-frequency choke coil.

FIG. 3 is a front view of the pedestal.

FIG. 4 is a partially enlarged longitudinal sectional view taken along line AA in the same plan view.

FIG. 5 is another embodiment relating to the arrangement of a dedicated karaoke terminal.

FIG. 6 is a plan view of another shape embodiment of the pedestal.

FIG. 7 is a plan view of another shape embodiment of the pedestal.

FIG. 8 is a perspective view showing the structure of a conventional surface mount type high frequency choke coil.

FIG. 9 is a plan view for explaining mounting by the automatic mounting apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Winding shaft part 2a, 2b Flange part 3 Drum-shaped core 4 Winding 5a, ... Lead terminal (also used as a helmet terminal) 6, 26 Pedestal 7, 26a Pedestal side surface 9 Pedestal root part 10, 20 High-frequency choke coil 11a, 11b ... Mechanical chuck part 14 Contact surface 15 Circular recess 21 Positioning surface 25 Lead terminal 26b Edge corner on base side of base 27 Body terminal 28 Oblique forming surface 29 Base bottom S1 Extension line X, X 'Mounting width f Outermost line

Claims (1)

(57) [Claims] 1. A surface-mount type coil component comprising: a drum-type core on which a winding is wound; and a pedestal on which a lead terminal for bonding and fixing the drum-type core and electrically connecting to the winding is implanted. In the above, the edge on the bottom surface side on the side where the lead terminals on the side of the pedestal are exposed has a shape cut off obliquely, and the dedicated terminal does not protrude beyond the outermost contour line of the pedestal on the oblique molding surface. In the same way as the projecting diagonally downward, the lead terminal, which is integrally connected to the terminal dedicated to the lashing and the inside of the pedestal, is located on the side surface of the pedestal to position the automatic chucking device on the mounting substrate. A surface-mount type coil component characterized by being arranged so as not to protrude from parallel opposing positioning surfaces for sandwiching.