JPH02238705A - Cylindrical lc noise file and its manufacture - Google Patents

Abstract

PURPOSE:To surely eliminate various types of noise by placing a 1st conductor opposite to a 2nd conductor formed in spiral via an insulation cylinder. CONSTITUTION:A 1st conductor 30 is coated along a spiral slot 12 to an inner circumferential face 10a of a cylinder 10 and both ends of the 1st conductor 30 are connected electrically to conductor layers 100a, 100b provided to an opening at both ends of the cylinder 10 and input and output lead wires 34a, 34b are connected to the conductor layers 100a, 100b. Moreover, a conductor layer 200 coated to an outer circumferential face of the cylinder 10 is used as a 2nd conductor 40 and the 2nd conductor 40 is placed opposite to the 1st conductor 30 with the cylinder 10 inbetween to form a capacitor. Thus, the produced noise is surely eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an LC noise filter having a completely new configuration using an insulating cylinder and a method for manufacturing the same.

[Background Art] With the recent development of electronic technology, electronic circuits are widely used in various fields, and it is desired to operate these electronic circuits stably and reliably without being affected by external influences.

However, noise enters the electronic circuit directly or indirectly from the outside, which often causes malfunctions in various electronic devices using the electronic circuit.

In order to remove such noise, various noise filters are generally used in electronic circuits.

In particular, in recent years, with the use of a large number of various high-performance electronic devices, regulations regarding noise have become increasingly strict, and for this reason, we have developed a compact yet high-performance noise filter that can reliably remove the generated noise. is desired.

[Problems to be Solved by the Invention] The present invention has been made in view of the above-mentioned conventional problems, and its purpose is to reduce LC noise by adopting a completely new configuration of using an insulating cylindrical body. The purpose is to provide filters.

[Means for Solving Problems by the Invention] In order to achieve the above object, the present invention includes an insulating cylindrical body, and an insulating material provided in a spiral shape on the inner circumferential surface or outer circumferential surface of the cylindrical body to function as an inductor. a first conductor; a second conductor that is provided on the outer or inner circumferential surface of the cylindrical body to face the first conductor through the cylindrical body and forms a capacitor with the first conductor; It is characterized by including the following.

Furthermore, the method of the present invention involves dipping an insulating cylinder, which has a spiral groove formed on its inner peripheral surface and is coated with a resist so as to form a conductive pattern of a predetermined shape on its outer peripheral surface, into a conductive tank. Then, by polishing and removing the conductive layer coated on the inner peripheral surface of the cylindrical body using a polishing member, a spiral-shaped first layer is formed on the inner peripheral surface.
, and a second conductor is formed on the outer circumferential surface so as to face the first conductor with the cylindrical body interposed therebetween.

Next, the operation of the present invention will be explained.

In the noise filter of the present invention, the second
A conductor and a first conductor formed in a spiral shape are arranged to face each other.

The first conductor is used as a signal line or a power supply line, and functions as an inductor by being formed in a spiral shape. Further, the second conductor forms a capacitor between it and the first conductor.

Therefore, the filter of the present invention functions as an LC noise filter consisting of L and C when viewed from the entire circuit.

In particular, according to the present invention, the first conductor used for the signal line or the power supply line is provided on the inner periphery of the cylindrical body,
Preferably, the second conductor is provided on the outer periphery of the cylindrical body,
By doing so, the noise radiated from the signal line or the power supply line is absorbed by the second conductor provided around the signal line or the power supply line, and the noise radiated from the line to the surroundings can be reduced.

Further, according to the noise filter manufacturing method of the present invention, an insulating cylinder in which a spiral groove is formed in advance and a resist for forming a second conductor is coated around the insulating cylinder is placed in a conductive tank. Dip inside. Thereafter, the cylindrical body is pulled up from the conductive tank, and the conductive material adhering to the inner peripheral surface of the cylindrical body is removed using a polishing means. As a result, only the conductive material attached to the spiral groove remains on the inner circumferential surface of the cylinder, which functions as the first conductor.

In addition, since a resist is applied to the outer circumferential surface of the cylindrical body so as to cover the second conductor having a predetermined shape, the outer circumferential surface can be coated with a predetermined shape by simply dipping the same body into a conductive bath. A second conductor will be coated.

In this manner, according to the method of the present invention, the L and C noise filters can be easily formed using the insulating cylinder.

[Example] Next, preferred embodiments of the present invention will be described based on the drawings.

First Embodiment FIG. 1 shows a preferred first embodiment of the LC noise filter according to the present invention.

When manufacturing the noise filter of the example, the method shown in Fig. 2 (
As shown in A), first, spiral grooves 12 at a predetermined pitch are formed on the inner circumferential surface of the cylindrical ceramic cylinder body 10.
Form it. In the example, this spiral
2 are formed at a constant pitch, and both ends thereof extend to the openings at both ends of the cylindrical body.

Further, resists 14a and 14b are coated in a ring shape on the outer circumferential surface of the cylinder 10 near the openings at both ends, so that no conductor will adhere to these parts.

Then, this cylindrical body 10 is dipped into a conductive tank 16 filled with a liquid conductive material, as shown in FIG. 2(B), so that the conductive material is attached to its surface.

Thereafter, the cylinder 10 is placed in the conductive tank 16 as shown in FIG.
When lifted from the
All are coated with conductive material. At this time, the conductive material attached to the surface of the cylinder 10 is electrically separated into two parts at the resists 14a and 14b, and one conductive layer 100 is formed to cover the inner surface of the cylinder 10 and both ends thereof. The other conductive layer 200 is formed to cover the outer peripheral surface of the cylinder 10 in a cylindrical shape.

Thereafter, after these conductive layers 100, 200 are dried, the surface polishing member 20 is used to remove the cylindrical body 10, as shown in FIG.
The conductive layer 100 attached to the inner circumferential surface 10a is removed. In the embodiment, the surface polishing member 20 is formed into a substantially cylindrical shape to match the inner diameter of the cylindrical body 10, and a surface polishing agent is provided on its outer peripheral surface. Then, this surface polishing member 2
0 is rotated while being inserted into the inner peripheral surface of the cylinder 10, and all of the conductive layer 100 adhering to the inner peripheral surface 10m is removed except for the conductive layer adhering to the inside of the spiral groove 12.

By doing this, as shown in FIG. 2D, the first conductor 30 is coated on the inner circumferential surface 10a of the cylinder 10 along the spiral groove 12, and both ends of the first conductor 30 are coated. is a conductive layer 100a provided at both end openings of the cylindrical body 10.
, 100b. and,
Input/output leads 34a, 34b are connected to each of these conductive layers 100a, 100b.

FIG. 1 CB) schematically shows the first conductor 30 spirally provided on the inner circumferential surface of the cylindrical body 10 in this manner.

Further, a conductive layer 200 coated on the outer peripheral surface of the cylindrical body 10
is used as the second conductor 40.

The second conductor 40 is disposed opposite to the first conductor 30 with the cylindrical body 10 in between, forming a capacitor between them. In an embodiment, this second conductor 40 is
A ground lead 42 is connected and used as a ground conductor.

As a result, in the noise filter of this embodiment, the first conductor 30 provided in a spiral manner functions as an inductor, and the second conductor 40 provided opposite thereto functions as an inductor.
functions as a capacitor, and operates as a normal mode noise filter consisting of C and C shown in FIG.

Therefore, by connecting the first conductor 30 to a signal line or a power supply line, noise can be removed from the signal or power supply current flowing through these lines.

In particular, according to this embodiment, the second conductor 40 is arranged to face the spirally wound first conductor 30, and a capacitor is formed between them in a distributed manner. Therefore, compared to a lumped constant type LC noise filter, the noise component can be effectively removed from the signal or power supply current propagating within the first conductor 30.

Further, according to this embodiment, a first conductor 30 connected to a signal line or a power supply line is provided inside the cylinder 10, and a second conductor 40 used as a ground conductor is further provided.
is provided on the outside of the cylindrical body 10. For this reason, the first
When a signal or power supply current flows through the conductor 30, the second conductor 40 absorbs the noise radiated from the first conductor 30 to the surroundings, thereby significantly reducing the noise radiated to the outside. It becomes possible.

Further, by providing the second conductor 40 with cuts or lines, for example, it is possible to reduce the eddy current flowing through the second conductor 40 and remove noise more effectively.

Further, the noise filter of this embodiment can also be formed as a distributed constant circuit in which L and C are distributed non-uniformly, as shown in FIG. By doing this, depending on the type of signal, only the noise component can be more effectively removed without causing distortion to the signal.

A noise filter having such a non-uniform distributed constant circuit has a pitch interval of the first conductor 30 formed in a spiral shape, for example, as shown in FIG. ,,l, can be formed by changing the cylindrical body 1 as shown in FIG.
It can also be formed by sequentially changing the diameter 2R of the inner peripheral surface 10a of 0.

Further, in the embodiment, both ends of the first conductor 30 are connected to the conductive layer 100 provided near the openings at both ends of the cylindrical body 10.
a, 100b, and this conductive layer 100a. 100b
Although the explanation has been given by taking as an example the case where the input/output leads 34a and 34b are taken out from the input/output leads 34a and 34b, the present invention is not limited to this. Leads 34a for direct human output at both ends of 30
．． 34b may be formed to connect.

Second Embodiment By the way, in the first embodiment, the second conductor is formed in a cylindrical shape so as to cover the outside of the first conductor 30 formed in a spiral shape. For example, when a signal current is applied, an eddy current is generated in the second conductor 40, and the expected inductance of the first conductor 30 may not be obtained.

That is, in such an LC noise filter,
A second conductor 40 serving as a ground conductor is capacitively coupled to the spiral-shaped first conductor 30 and also inductively coupled. Therefore, the spiral first conductor 3
Due to the magnetic flux generated by the current of 0, an electromotive force is also generated on the second conductor 40, and this electromotive force causes the second conductor 40 to
Eddy currents will occur above.

If the spiral-shaped first conductor 30 is compared to the primary coil in a transformer, the second conductor 40 as a ground conductor acts like a short-circuited secondary coil, and the spiral-shaped first conductor 30 In this case, the expected inductance L may not be obtained, and there is a possibility that a sufficient function as an LC noise filter may not be exhibited.

In order to solve this problem, it is conceivable that the second conductor 40 serving as the ground conductor is provided with lines or cuts to create a structure in which eddy currents are less likely to flow. However, even if this is done, an eddy current still flows through the second conductor 40, although the value becomes smaller.

Based on these facts, the present inventor has determined how to form the second conductor 40 with respect to the first conductor 30 that is formed in a spiral shape and functions as an inductor.
We proceeded with the study on whether it is possible to obtain an LC noise filter with good characteristics without impairing the function of the conductor 30 as an inductor.

The inventor of the present invention has proposed that the inductance of the first conductor 30 can be reduced by forming the second conductor 40 so as not to obstruct the magnetic path of the magnetic flux generated when the spiral-shaped first conductor 30 is energized. It has been found that it is possible to obtain an LC noise filter with good electrical characteristics without degrading the electrical characteristics.

FIGS. 10 to 13 show preferred embodiments of the present invention made from this viewpoint.

In the noise filter of this embodiment, a first conductor 30 is formed in a spiral shape on the inner circumferential surface 10a of the cylindrical body 10, as shown in FIG. 1(B), as in the first embodiment.

Further, as shown in FIG. 10, in the noise filter of the embodiment, a second conductor 40 is formed in a spiral shape on the outer peripheral surface 10b of the cylindrical body 10 so as to face the first conductor 30,
The first conductor 30 and the second conductor 40 are capacitively coupled by capacitance, and a capacitor is formed between them.

Input/output leads 34a, 34b, 42a, 42b are connected to both ends of each of these conductors 30, 40.

In this case, the second conductor 40 is formed by coating the outer circumferential surface 10b of the cylindrical body 10 with a resist so that the conductor is coated in a spiral shape, for example, as shown in FIG.
0 may be formed by dipping into the conductive layer. In addition to this, for example, as shown in FIG.
A spiral groove 44 is formed in advance on the outer periphery of the conductor 40. After dipping the cylindrical body 10 into a conductive bath, the outer peripheral surface is polished to leave only the conductive layer attached to the groove 44.
may be formed.

FIG. 13 shows an equivalent circuit diagram of the LC noise filter of this embodiment, and in this embodiment, the first conductor 30 formed in a spiral shape functions as the first inductor L1. In addition, the first conductor 30 and the second conductor 4
0 are formed in a spiral shape so as to sandwich the cylindrical body 10 and face each other, so that they are capacitively coupled to each other by electrostatic capacitance, and a capacitor C is formed between them in a distributed constant manner. Become.

Furthermore, since the second conductor is formed in a spiral shape, the second conductor 40 also functions as the second inductor L2.

Therefore, the noise filter of this embodiment functions as a distributed constant type LC noise filter having a circuit configuration as shown in FIG.

In particular, in the noise filter of the present invention, the second conductor 40 that forms a capacitor with the first conductor 30 is formed so as not to interfere with the magnetic path of the first conductor 30.

That is, the magnetic flux generated when the first conductor 30 is energized passes between the lines of the first conductor 30 from the back side of the cylinder 10 to the front side, or in the opposite direction.

At this time, if the second conductor 40 is provided so as to obstruct this magnetic path (for example, if the second conductor 40 is provided so as to face the interline region of the first conductor 30), The magnetic path may be blocked by the second conductor 40, and the first conductor 30 may not be able to function sufficiently as an inductor.

On the other hand, according to the present invention, the second conductor 40 is arranged in a spiral shape so as to face the first conductor 30 in the spiral shape.
By providing this, the magnetic path of the first conductor 30 is not obstructed in any way by the second conductor 40. Therefore, the effect as an LC noise filter can be fully exhibited without reducing the inductance of the spiral first conductor 30.

Therefore, for example, the input/output lead 42a of the second conductor 40,
42b to the ground terminal and the input/output leads 34a, 34b of the first conductor 30 to the input/output terminals, the noise filter of this embodiment has good electrical characteristics. It can be used as a normal mode noise filter.

In addition, the j111. If the individual output leads 34a, 34b, 42a, 42b of the second conductor 30, 40 are used as input/output terminals, the noise filter of this embodiment is a four-terminal type common mode with good electrical characteristics. It can be used as a type noise filter.

Third Embodiment FIG. 14 shows a third preferred embodiment of the present invention.

As shown in FIG. 14(B), the LC noise filter of the embodiment has two sets of inductor conductors 30a and 30b formed in a spiral shape on the inner circumferential surface 10a of a cylinder 10 as first conductors. As shown in FIG. 14(A), each of the inductor conductors 30a, 30b is provided on the outer peripheral surface 10b of the cylinder 10.
Two sets of capacitor conductors 40a, 40b facing each other
is formed in a spiral shape as a second conductor to form a common mode type LC noise filter as shown in FIG.

That is, in the noise filter of the embodiment, as shown in No. 14 (B), the first inductor conductor 30a and the second inductor conductor 30b are formed in a spiral shape on the inner circumferential surface 10a of the cylindrical body 10 so as to be adjacent to each other. has been done. The outer ends of each inductor conductor 30a, 30b are connected to conductive layers 100a, 110a, 100b, 1 provided at both end openings of the cylindrical body 10.
10b.

And each of these conductive layers 100a, 110a, 100b
, 110b have input/output leads 34a, 36a, 3.
4b and 36b are connected.

Further, as shown in FIG. 14(A), a capacitor conductor 40a is formed in a spiral shape on the outer circumferential surface 10b of the cylinder 10 so as to face the inductor conductor 30a, and similarly to face the inductor conductor 30b. The capacitor conductor 40b is formed in a spiral shape. Each of these capacitor conductors 40a, 40b is electrically connected to each other at one end side and connected to a ground lead 42a.

FIG. 15 shows an equivalent circuit diagram of the LC noise filter of this embodiment, and in this embodiment, the inductor conductor 30a formed in a spiral shape is connected to the first inductor L.
The inductor conductor 30b, which is also formed in a spiral shape, functions as the second inductor L2.

The two sets of capacitor conductors 40a and 40b provided on the outer circumferential surface 10b of the cylinder 10 do not interfere with the magnetic path between the two sets of inductor conductors 30a and 30b that face each other with the cylinder 10 in between. The capacitors are formed in a distributed constant manner so that there is no problem.

Therefore, the noise filter of this embodiment can fully exhibit its effects as a common mode LC noise filter without reducing the inductance of each inductor conductor 30a, 30b.

Fourth Embodiment By the way, in the first to third embodiments, when a signal current or a power supply current is passed through the first conductor 30 functioning as an inductance, when the frequency of the current increases, the first conductor 30 is wound in a spiral shape. A problem arises in that a line-to-line short circuit occurs in the first conductor 30, and the first conductor 30 no longer functions sufficiently as an inductor.

In particular, such line-to-line short circuit phenomenon occurs more frequently as the frequency of the energizing signal becomes higher, so countermeasures are required.

FIG. 16 shows a preferred embodiment of the present invention that solves this problem.

The feature of this embodiment is that a shield conductor 60 is formed in a spiral shape between the lines of the first conductor 30 formed on the inner circumferential surface 10a of the cylindrical body 10, as shown in FIG. 16(B). It is in.

One end of the shield conductor 60 is electrically connected to a conductive layer 100c formed on the end surface of the cylindrical body 10.

Further, in the noise filter of this embodiment, as shown in FIG. 16(A), a shield conductor 70 is formed in a spiral shape on the outer peripheral surface of the cylindrical body 10 between the lines of the second conductor 40. , one end of this shield conductor 70 is similarly connected to a conductive layer 100.
connected to c.

This conductive layer 100c is connected to a ground lead 72.

With the above configuration, in the noise filter of this embodiment, the distance between the first and second conductors 30 and 40 is
Since it is shielded by each shield conductor 60, 70 and the occurrence of a short circuit phenomenon between the lines is prevented, it functions as a noise filter having excellent electrical characteristics from a low frequency band to a high frequency band.

In particular, in this embodiment, not only the first conductor 30 but also the second conductor 40 are shielded to prevent a single short circuit between the lines, so this is suitable for use as a common mode noise filter. becomes.

Note that when the noise filter of this embodiment is used as a normal mode noise filter, the first conductor 3
It is sufficient to provide the shield conductor 60 that prevents a short circuit between the lines of the second conductor 40, and it is not necessary to provide the shield conductor 70 that prevents a short circuit between the lines of the second conductor 40.

Fifth Embodiment FIG. 17 shows a fifth preferred embodiment of the present invention.

The feature of this embodiment is that in the noise filter shown in FIG.
As shown in Figure (B), a first shield conductor 60a is formed, and a second shield conductor 60b is similarly formed in a spiral shape between the inductor conductors 30b and 30a.
This is because the space between each inductor conductor 30a and 30b is shielded.

One ends of the various conductors 60a and 60b are connected to a ground lead 72 via a conductive layer 100c provided on opposite end surfaces of the cylinder 30.

By doing so, according to this embodiment, a common mode noise filter having excellent electrical characteristics from low frequency to high frequency bands can be obtained.

Sixth Embodiment Also, in the LC noise filter of the present invention, the first
In addition to the number of turns and arrangement of the conductor 30 and the second conductor 40, by appropriately selecting the material of the cylinder 10, the inductance L and capacitance C of the noise filter can be set arbitrarily.

For example, if you want to increase the inductance L,
The cylinder 10 may be formed using a magnetic material or the like, or may be dipped in magnetic powder. Furthermore, if it is desired to increase the capacitance C, the cylinder 10 may be formed using a material with a high dielectric constant such as ceramics. Again, these L
When trying to increase both C and C, the cylindrical body 1
0 may be formed using both a material with a high dielectric constant and a magnetic material.

In addition, if it is desired to increase the inductance L, for example, the hollow portion of the cylinder 10 may be filled with a magnetic material, and in this way, a noise filter with a large L component can be formed.

FIGS. 18 and 19 show preferred embodiments of the present invention made from this viewpoint. In the noise filter of the embodiment, a spiral thread groove 80 is formed on the inner circumferential surface 10a of the cylindrical body 10, and the first conductor 30 is coated on the bottom of this thread m80. As a result, the first conductor 30 is formed in a spiral shape as in each of the embodiments described above.

Although not shown, a second conductor 40 is formed in a spiral shape on the outer circumferential surface of the cylindrical body 10 so as to face the first conductor 30.

This cylinder 10 has a screw 90 with its thread 9
2 is screwed into the screw groove 80. In this, the thread 92 is
The top part is formed flat so as not to come into contact with the first conductor 30 formed at the bottom part when it is screwed into the thread groove 80.

The feature of this embodiment is that this screw 90 is formed using a magnetic material.

Thereby, by adjusting the depth to which the screw 90 is screwed into the cylinder 10, each inductance Ll, L2 of the first conductor 30 and the second conductor 40 can be adjusted to an arbitrary value, and the inductance can be adjusted. This makes it extremely suitable as an LC noise filter that requires

Other Examples It should be noted that the present invention is not limited to the above embodiments,
Various modifications can be made within the scope of the invention.

For example, the second to fifth embodiments can be formed as a noise filter having a circuit with non-uniform distributed constants, similar to the first embodiment.

In this case, for example, as shown in FIG. 5, the pitch interval of the first conductor 30 formed in a spiral shape may be changed, or as shown in FIG. The diameter 2R of the surface 10a may be changed.

Also in the second to fifth embodiments, the first conductor 3
Directly connect both ends of 0 without using a conductive layer in Figure 7~'tll9
As shown in the figure, it may be formed so as to be connected to human output leads 34a and 34b.

Further, in each of the above embodiments, the first conductor 3
0 is coated on the inner circumferential surface 10a of the cylindrical body 10, but the present invention is not limited to this, and the first conductor 30 may be formed on the outer circumferential surface 10b of the cylindrical body 10 as necessary. , the second conductor 40 may be formed on the inner periphery of the cylindrical body 10.

Further, in the above embodiments, the case where the cylinder body 10 is dipped in a conductive tank to form each conductor 30 and 40 has been described as an example, but the present invention is not limited to this, and for example, the first conductor 30 and As the conductor 40, a conductive wire previously wound in a spiral shape may be used, and as the conductor 40, a conductive plate or a conductive wire formed in a cylindrical or spiral shape may be used.

Furthermore, the LC noise filter of the present invention can be used as a high frequency noise filter for signal lines and as a low frequency noise filter for power supply lines. When used as a high frequency noise filter, it is preferable to set the values of L and C to small values, and when used as a low frequency noise filter for power supply lines, it is preferable to set the values of L and C to small values.
It is preferable to set the values of and C to be large.

In particular, when the noise filter of the present invention is used as a high frequency filter, it functions as a noise filter in which L and C are distributed constants. It has the excellent effect of being able to be removed.

Further, in this embodiment, the conductor 30 is formed by forming the cylinder lO using a material such as a high frequency absorption heating element.
Noise emitted from signals passing through the filter, especially high-frequency noise, is absorbed as heat, making it possible to more effectively remove noise.

Further, in this embodiment, the case where the cylinder 10 is formed into a cylindrical shape has been described as an example, but cylinders having various shapes other than this may be used as necessary.

For example, by forming the cylindrical body 10 into a rectangular cylindrical body as shown in FIG. 20, the filter of the present invention can be formed as an SMD type electronic component.

Further, by connecting the filter of the present invention to each channel of a multi-channel plug or a multi-channel socket (not shown) shown in FIG. 21, a multi-channel noise filter can be easily formed.

For example, if we take the multi-channel plug shown in FIG. By providing it inside, a multi-channel noise filter can be configured.

[Effects of the Invention] As explained above, according to the present invention, a novel configuration is adopted in which a first conductor and a second conductor formed in a spiral shape are opposed to each other via an insulating cylinder. By doing so, it becomes possible to provide a cylindrical noise filter that can reliably remove various types of noise.

In particular, in the present invention, the first spirally formed
By forming the second conductor in a spiral shape to face the first conductor so as not to obstruct the magnetic path of the magnetic flux generated when the conductor is energized, the inductance of the first conductor can be reduced. It is possible to obtain a cylindrical LC noise filter that has excellent electrical characteristics without deterioration.

Further, according to the present invention, by providing a shield conductor between the spiral-shaped first conductors to prevent this line-to-line short circuit, noise components can be removed without causing line-to-line short circuits even in high frequency bands. A cylindrical LC noise filter can be obtained.

[Brief explanation of drawings]

FIGS. 1A and 1B are explanatory diagrams showing an example of the LC noise filter according to the present invention, FIGS. 2A to 2D are explanatory diagrams showing the manufacturing process of the noise filter of the present embodiment, 3 is an equivalent circuit diagram of the noise filter shown in FIG. 1, FIG. 4 is an equivalent circuit diagram of another embodiment of the noise filter of the present invention, and FIGS. 5 and 6 are equivalent circuit diagrams of the noise filter shown in FIG. 4. FIGS. 7 to 9 are explanatory diagrams showing other specific examples of the noise filter of the present invention shown in circuit diagrams. FIGS. 10 to 12 are illustrations of the noise filter of the present invention. FIG. 13 is an equivalent circuit diagram of FIGS. 10 to 12, and FIGS. 14 (A) and (B) are explanatory diagrams of a third preferred embodiment of the present invention. , FIG. 15 is an equivalent circuit diagram of FIG. 14, and FIG. 16 (A). (B) is an explanatory diagram of a third preferred embodiment of the present invention; FIG. 17 (A). (B) is an explanatory diagram of a fourth preferred embodiment of the present invention, FIGS. 18 and 19 are explanatory diagrams of a fifth preferred embodiment of the present invention, and FIG. 20 is an explanatory diagram of the present invention formed as an SMD type. FIG. 21 is an explanatory diagram of a multi-channel noise filter formed using the present invention. 10... Cylindrical body, 12... Spiral groove, 14
. . . Resist, 16 . . . Conductive tank, 30 . . . First conductor, 30a. 30b...Inductor conductor 40...Second conductor, 40a, 40b...Capacitor conductor, 60.70...
- Sealed conductor, 80...thread groove, 90...screw, 92...thread thread. Agent Patent attorney Husband (2 others) Figure (B) Figure (D) Figure 11 →==0 4zz Figure 14 (B) Figure 16 (8) Figure 20

Claims (15)

[Claims] (1) An insulating cylindrical body, a first conductor provided in a spiral shape on the inner or outer peripheral surface of this cylindrical body and functioning as an inductor, and a cylindrical body on the outer or inner peripheral surface of this cylindrical body. A cylindrical LC noise filter comprising: a second conductor that is disposed to face the first conductor and forms a capacitor with the first conductor. (2) In claim (1), both ends of the first conductor are connected to input/output leads, respectively, and the second conductor is connected to a ground lead and is molded as a normal mode type. Cylindrical LC noise filter. (3) The cylindrical noise filter according to claim (2), wherein the second conductor is formed with cuts or lines to reduce eddy current. (4) According to claim (1), the second conductor is formed in a spiral shape so as to face the first conductor, and forms a capacitor with the first conductor. LC noise filter. (5) In claim (4), both ends of the first conductor are connected to input/output leads, and the second conductor is connected to a ground lead and is formed as a normal mode type. Cylindrical LC noise filter. (6) The cylindrical LC noise filter according to claim (4), wherein the first and second conductors are each connected to an input/output lead at both ends thereof and are formed as a common mode type. (7) In claim (4), the first conductor includes at least two sets of inductor conductors formed in a spiral shape so as to be adjacent to each other on one of the inner circumferential surface or the outer circumferential surface of the cylindrical body, The second conductor is formed in a spiral shape on the other surface of the cylindrical body so as to face each of the inductor conductors, and includes at least two sets of capacitor conductors that form a capacitor with each of the inductor conductors. The set of inductor conductors is
A cylindrical LC noise filter characterized in that both ends thereof are connected to input/output leads, respectively, and formed as a common mode type. (8) In any one of claims (1) to (7), provided on one surface of the cylinder, located between the lines of the first conductor,
A cylindrical LC noise filter characterized by being provided with a shield conductor for preventing line-to-line short circuit of the first conductor. (9) In claim (8), a shield conductor is provided on the other surface of the cylindrical body and is located between the lines of the second conductor to prevent short circuit between the lines of the second conductor. A cylindrical LC noise filter featuring: (10) A cylindrical LC noise filter according to any one of claims (1) to (9), characterized in that the spiral spacing of the first conductor is changed to unevenly distribute L and C. (11) In any of claims (1) to (10),
A cylindrical LC noise filter characterized in that a hollow portion of the cylindrical body is filled with a magnetic material. (12) In claim (11), a thread groove is formed in the hollow inner wall of the cylinder, and the magnetic material is screwed into the thread groove so that the depth of penetration into the hollow part of the cylinder can be arbitrarily adjusted. 1. A cylindrical LC noise filter, characterized in that the cylindrical LC noise filter is formed in a screw shape, and is formed so as to adjust the inductance to an arbitrary value by changing the penetration depth of the screw-shaped magnetic material in the hollow part of the cylindrical body. (13) In any of claims (1) to (12),
A cylindrical LC noise filter characterized in that the cylindrical body is formed using an electromagnetic wave absorbing heating element. (14) In any of claims (1) to (13),
A cylindrical LC noise filter, wherein the second conductor is provided on the outer periphery of the cylindrical body, and the first conductor is provided on the inner periphery of the cylindrical body. (15) An insulating cylinder with spiral grooves formed on its inner peripheral surface and coated with a resist to form a conductive pattern of a predetermined shape on its outer peripheral surface is dipped into a conductive tank, and then the cylinder is By polishing and removing the conductive layer coated on the inner circumferential surface using a polishing member, a spiral-shaped first conductor is formed on the inner circumferential surface, and a first conductor is formed on the outer circumferential surface through the cylindrical body.
A method for manufacturing a cylindrical LC noise filter, comprising forming a second conductor to face the conductor.