JPH0644163Y2 - Filter using a helical coil - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field of the Invention The present invention relates to a filter using a helical coil that can be used as a duplexer or the like.

2. Description of the Related Art As a high performance filter, there is a duplexer installed in a transmission / reception circuit of a communication device. FIG. 4 shows an example of the circuit of the duplexer. This is a Triman capacitor
It has a basic circuit configuration in which a plurality of T-shaped circuits each including a C1, a coil 12, a helical coil L1, and a capacitor C2 (or a Corui L3) are connected in multiple stages. , The stray capacitance between the helical coil L1 and the metal chassis 10 is used.

FIG. 5 is a side view showing the internal structure of a conventional duplexer.

The metal chassis 10 is a box body including a bottom plate 12, an intermediate plate 13, a top plate, and side plates (none of which are shown). Inside the metal chassis 10, a plurality of rooms are formed by a partition plate 14 that is erected at a predetermined interval between the bottom plate 12 and the intermediate plate 13.
The helical coil L1 and capacitor C2 (or coil L
3) are arranged respectively.

Further, in the hollow plate 13 as well, a through terminal 50 and a trimmer capacitor C1 are provided in a portion corresponding to the upper side of the room,
Especially, the trimmer capacitor C1 has its ground terminal connected to the intermediate plate 13
Is soldered to. Further, the coil L2 and the trimmer capacitor C1 are soldered to the upper end side of the through terminal 50, respectively. On the other hand, one end of the capacitor C2 (or coil L3) is soldered to the lower end side of the through terminal 50, and the through terminal
Helical coil L1 for ground terminal 51 that uses a part of 50
One end of is soldered. Moreover, the helical coil L1
The other end of the capacitor C2 (or the coil L3) is soldered to the middle part of the.

Then, the side plate and the top plate are screwed to the frame body composed of the bottom plate 12, the intermediate plate 13, and the partition plate 14 by a screw, so that the duplexer is assembled.

However, in the case of the above-described conventional example, the through terminal 50
It is difficult to solder and wire the coil L2 and the trimmer capacitor C1 to the upper end side of the wire in the air, and it cannot be handled by a skilled person, resulting in a high assembly cost. In addition, the relatively high unit price of the through terminal 50 is also a major obstacle in promoting cost reduction as a whole.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a filter using a helical coil that can be easily assembled by an unskilled person. is there.

Means for Solving the Problems A filter using a helical coil according to the present invention is
It has a helical coil that is provided inside the metal frame and is hollowly supported inside the metal frame by once soldering it to the inner surface of the metal frame, and a capacitor, coil, and other circuit elements. A filter using a helical coil that utilizes a stray capacitance between a helical coil and a metal frame to electrically connect the circuit element and a portion other than one end of the helical coil to form a filter circuit as a whole. A printed circuit board mounted on the outside of the metal frame and having all or a part of the circuit element mounted thereon, and a pattern formed on the printed circuit board and standing upright toward the metal frame. A connection terminal electrically connected to the circuit element through an opening formed in the outer surface of the metal frame and through which the connection terminal is inserted into the metal frame. Has a, is characterized in that as soldered to portions other than the one end of the helical coil and through the other part of the direct or the circuit element the tip portion of the connection terminal.

Function By helically soldering one end of the helical coil to the inner surface of the metal frame, the helical coil is hollowly supported inside the metal frame. All or part of capacitors, coils, and other circuit elements are mounted on a printed circuit board. When the printed circuit board is attached to the outside of the metal frame body, the tip portions of the connection terminals standing on the printed circuit board enter the inside of the metal frame body through the openings. In this state, the tip portion of the connection terminal is soldered to a portion other than one end of the helical coil directly or through another portion of the circuit element. With this, the circuit element and the helical coil are electrically connected to each other through the connection terminal, and the filter circuit using the stray capacitance between the helical coil and the metal frame is configured as a whole.

Embodiment Hereinafter, a filter using a helical coil according to the present invention will be described with a duplexer as an example with reference to the drawings. 1 is a side view showing the internal structure of the duplexer, FIG. 2 is a view taken along the line AA in FIG. 1, FIG. 3 is a view taken along the line BB in FIG. 1, and FIG. The figure is a circuit diagram of the duplexer.

The duplexer listed here is equipped in the transmission / reception circuit of the communication device, and as shown in FIG. 4, the trimmer capacitor C1, the coil L2, the helical coil L1, and the capacitor C2.
(Or the coil L3) has a circuit configuration in which a plurality of T-shaped circuits are connected in multiple stages. Further, the helical coil L1 is hollow-supported inside the metal chassis 10 so as to utilize the stray capacitance between the helical coil L1 and the metal chassis 10 (note that the trimmer capacitor C1 and the coil L2 are used).
Corresponds to a part of the circuit element for one circuit in the T-type circuit.

The circuit components of this duplexer are housed inside a metal chassis 10 (part of which corresponds to a metal frame) as shown in FIG. The metal chassis 10 is a bottom plate that is a copper plate
A box body including an intermediate plate 13, an intermediate plate 13, a top plate (not shown), and a side plate 15 (see FIG. 2).
And a partition plate that is erected with a predetermined gap between the intermediate plate 13 and the intermediate plate 13.
14 will form multiple rooms.

Inside this room is helical coil L1 and capacitor C2
(Or the coil L3) is stored, but details will be described later.

Between the intermediate plate 13 and the top plate (not shown), a trimmer capacitor C1
A printed circuit board 20 on which the coil L2 is mounted is provided. This printed circuit board 20 is an intermediate plate through a spacer 30.
It is attached to 13 mag.

In the figure, 31 is a screw for attaching the printed circuit board 20 to the intermediate plate 13, and also serves as a screw for fixing the partition plate 14 to the intermediate plate 13.

Then, as shown in FIG. 1, a bottom plate 12, an intermediate plate 13, a partition plate
Side plates 15 and 15 (see FIG. 2) are screwed to both sides of the frame body constituted by 14, and a top plate (not shown) is attached to the screwed frame body so as to cover the upper side of the printed circuit board 20. When further screwed, the metal chassis 10 can be assembled.

The interior of the metal chassis 10 will be described in detail. The intermediate plate 13 has an opening 50 and a solder heat diffusion preventing hole 60 as shown in FIG. This is a helical coil
It is provided for each room that stores L1 etc. Among them, the solder heat diffusion prevention hole 60 is composed of four holes arranged symmetrically to each other, and a portion corresponding to the center of these four holes. One end of the helical coil L1 is soldered. In the figure, α indicates solder.

When one end of the helical coil L1 is soldered to the intermediate plate 13 in this manner, the helical coil L1 is hollowly supported inside the chamber as shown in FIG. Also, the helical coil
A capacitor C2 (or coil L3) (T
It corresponds to the other part of the circuit element for one circuit in the mold circuit)
One end of the is to be soldered. On the other hand, the other end of the capacitor C2 (or the capacitor L3) enters the above-mentioned room through the opening 50 of the intermediate plate 13 and has a connection terminal 40 described later.
Are to be soldered.

Reference numeral 121 in FIG. 1 indicates the helical coil L1 and the metal chassis 1.
A screw provided on the bottom plate 12 for adjusting the stray capacitance with 0.

The connection terminals 40 are metal rods which are vertically erected on the back surface of the printed board 20, and are connected to a pattern (not shown) formed on the front surface or the back surface of the printed board 20.
That is, when the printed circuit board 20 is attached to the intermediate plate 13,
The lower end of the connection terminal 40 passes through the center of the opening 50 formed in the intermediate plate 13 and enters the inside of the room.

Since the size of the opening 50 is set to be larger than that of the upper connection terminal 40, the connection terminal 40 does not come into contact with the intermediate plate 13.

By the way, reference numeral 151 in FIG. 2 denotes a contact member made of resin or the like for preventing the helical coil L1 from moving inside the metal chassis 10. Since this tip portion has a shape that fits the outer shape of the helical coil L1, it is necessary to prevent its angle from being displaced when it is attached to the side surface plate 15. In the present embodiment, the method of attaching the contact member 151 to the side plate 15 is such that a protrusion (not shown) having a concave cross-section formed on the attachment surface of the contact member 151 is formed on the side face plate 15 corresponding to the protrusion. A method of fitting in a fitting hole (not shown) is adopted. According to such a method, it does not require time and labor for mounting, and the contact member 151 also has the side plate 15 at a desired angle.
There is a merit that it can be securely attached to.

Next, a process until the duplexer is assembled will be described with reference to FIG.

First, one end of the capacitor C2 (or the coil L3) is soldered to the middle part of the helical coil L1. Then, one end of the helical coil L1 is provided with a hole for preventing solder heat diffusion in the intermediate plate 13.
Solder near 60.

Before and after this, the trimmer capacitor C1, the coil L2, etc. are mounted on the pattern surface of the printed circuit board 20 by soldering,
The printed circuit board 20 is screwed to the intermediate plate 13. In this state, the tip of the connection terminal 40 is inserted into the opening 50 of the intermediate plate 13, but due to the size of the two, the connection terminal 40 and the intermediate plate 13 do not come into contact with each other and are in an air-insulated state. .

Then, the other end of the capacitor C2 (or the coil L3) is soldered to the tip of the connection terminal 40. Finally, bottom plate 12, middle plate
When the side plate 15 and the top plate (not shown) are screwed to the frame body including the partition plate 15, the assembly of the dupcresa is completed. When the side plates 15 and 15 are attached, the helical coil L1 is sandwiched between the contact members 151 and 151 and positioned and fixed.

With the duplexer as described above, the following advantages can be obtained.

That is, when the helical coil L1 is soldered to the intermediate plate 13, the heat given to the intermediate plate 13 from the soldering iron does not spread to the entire intermediate plate 13 due to the presence of the solder heat diffusion preventing holes 60, Only the part to be attached is given intensively,
The soldering work can be performed easily and surely here.

The printed circuit board 20 also has a trimmer capacitor C1 and a coil L2.
In mounting, it is not necessary to perform air wiring as in the conventional case, and it is sufficient to mount it on the printed circuit board 20, so that the soldering work can be performed extremely easily as compared with the conventional case.
Therefore, even an unskilled person can easily engage in the assembly work, and as a result, the assembly cost can be reduced.

Further, since the structure does not use the through terminal having a high unit price, the cost of parts can be reduced, which is very significant in promoting the cost reduction as a whole.

The filter using the helical coil according to the present invention can be applied not only to the duplexer but also to a normal high-pass filter or low-pass filter. In addition, it may not be necessary to provide the solder heat diffusion preventing holes depending on the conditions such as the size of the metal frame.

Effects of the Invention As described above, in the case of the filter using the helical coil according to the present invention, all or part of the circuit element can be mounted on the printed circuit board without hollow wiring. Even if it is not, the assembling work can be performed, and as a result, the assembling cost can be reduced.
Moreover, since the structure does not require a through terminal having a high unit price, the cost of parts can be reduced. Therefore, there is an advantage that the cost required as a whole can be reduced as compared with the conventional one.

[Brief description of drawings]

1 to 4 are views for explaining an embodiment of a filter using a helical coil according to the present invention, wherein FIG. 1 is a side view showing the internal structure of a duplexer, and FIG. Is a view taken along the line AA in FIG. 1, FIG. 3 is a view taken along the line BB in FIG. 1, and FIG.
The figure is a circuit diagram of the duplexer. Further, FIG. 5 is a diagram corresponding to FIG. 1 for explaining a conventional duplexer. 10 …… Metal chassis 20 …… Printed circuit board 40 …… Connection terminal 50 …… Opening L2 …… Coil C1 …… Trimmer capacitor L1 …… Helical coil

Claims (1)

[Scope of utility model registration request] 1. A helical coil, which is provided in a metal frame body and is hollowly supported inside the metal frame body by soldering one end to the inner surface of the metal frame body, and a capacitor, a coil and other circuit elements. Uses a helical coil that has a filter circuit as a whole by utilizing the stray capacitance between the helical coil and the metal frame and electrically connecting the circuit element and a portion other than one end of the helical coil. A printed circuit board mounted on the outside of the metal frame and having all or part of the circuit elements mounted thereon, and standing on the printed circuit board toward the metal frame side and on the printed circuit board. A connection terminal electrically connected to the circuit element through a pattern formed on the metal frame, and the connection terminal formed on the outer surface of the metal frame body and inside the metal frame body. And a tip end portion of the connection terminal is soldered directly or through another portion of the circuit element to a portion other than one end of the helical coil. A filter that uses a coil.