JP2020088294A - Noise prevention resistor and manufacturing method thereof - Google Patents

Abstract

To provide a noise prevention resistor and a manufacturing method thereof with a predetermined noise suppression characteristic.SOLUTION: A noise prevention resistor includes: a magnetic material (ferrite) 15 in a substantially central part of a core material 5 in the axial direction; a portion 13 of the magnetic material 15 which is made of glass fiber and is not impregnated with an adhesive on the outer circumferential side; and an impregnation portion 14 of a fixing agent in the glass fiber on the outer side in the circumferential direction of the portion 13. As a result, an inductance for ensuring the noise suppression effect is obtained in a predetermined frequency range, and a noise prevention resistor functions as a noise filter having a resonance frequency or a cutoff frequency within a predetermined frequency range.SELECTED DRAWING: Figure 11

Description

The present invention relates to a noise prevention resistor mounted on, for example, an engine ignition device of a vehicle and a manufacturing method thereof.

In vehicles equipped with a gasoline engine, such as automobiles and motorcycles, a high-voltage current is applied to the spark plug (spark plug) of the engine ignition device to cause discharge, and a spark is ignited by blowing a compressed mixed gas of gasoline and air in the cylinder. However, in order to suppress the high frequency noise (noise) generated by the discharge during engine ignition, a noise prevention resistor is connected in series between the body of the ignition coil and the spring connected to the spark plug. ..

A winding resistor has been conventionally used as such a noise prevention resistor. For example, in the resistor of Patent Document 1, a core material prepared by impregnating and fixing an insulating body in which a large number of wires made of an insulating material such as glass fiber are bundled with a heat-resistant adhesive such as silicon varnish, and the outer peripheral surface of which is made of carbon The fiber yarn is continuously wound (wound). Then, a winding resistor in which a cap is applied to both ends of a resistance element, which is obtained by further coating a thin layer of heat-resistant varnish on the surface of the winding body, baking and hardening, and drying and cutting the resistance element, is disclosed. There is.

JP-A-59-115501

The noise prevention resistor mounted on the engine ignition device preferably has a high inductance value and a high resistance value in order to suppress high frequency noise (high frequency noise) generated during engine ignition.

The conventional wire-wound resistor described in Patent Document 1 or the like depends on the noise suppression effect depending on the wire diameter and the number of turns of the resistance wire. As a result, there is a problem in that it is difficult to obtain the inductance value required to enhance the noise suppression effect in the low frequency region (for example, suppress noise of 30 MHz or higher).

The present invention has been made in view of the above-described problems, and an object thereof is to provide a noise prevention resistor having a high inductance value and noise suppression characteristics in a predetermined low frequency region, and a method for manufacturing the same. It is to be.

The following configuration is provided as one means for achieving the above object and solving the above-mentioned problems. That is, the present invention provides a pair of resistors at both ends of a resistance element including an insulating core material, a resistance wire wound around the outer peripheral surface of the core material, and an insulating coating covering the outer peripheral surfaces of the core material and the resistance wire. The noise preventing resistor having the cap terminal attached thereto, wherein the core material is composed of a bundle of insulating fibers, a fixing agent, and a magnetic material.

In the noise prevention resistor, for example, the magnetic material is ferrite, an iron-based alloy, iron oxide, chromium oxide, or manganese oxide. For example, the ferrite is Ni-based ferrite or Mn-based ferrite. Further, for example, a non-impregnated portion of the adhesive is provided on the outer side in the circumferential direction of the magnetic material that is disposed substantially in the center of the core material in the axial direction, and the adhesive is impregnated on the outer side of the non-impregnated portion in the circumferential direction. It is characterized by having a part. In addition, for example, the entire region on the outer side in the circumferential direction of the magnetic material arranged in the substantially central portion of the core material in the axial direction is set as the impregnated portion of the adhesive. Further, for example, the surface layer portion of the core material serves as an impregnated portion of the adhesive, and the magnetic material is dispersed in the adhesive. Further, for example, the whole area of the core material is an impregnated portion of the adhesive, and the magnetic material is dispersed in the adhesive. Further, for example, the content of the magnetic material in the core material is 5% or more and 85% or less in terms of a sectional area ratio of the core material. Furthermore, for example, the content of the magnetic material is preferably 10% to 40% in terms of a cross-sectional area ratio of the core material.

Further, the method for manufacturing a noise prevention resistor according to the present invention comprises a step of forming a long core material, a step of winding a resistance wire around the outer periphery of the core material, and a core around which the resistance wire is wound. A step of forming a resistance element by cutting the material into a predetermined size and a step of attaching cap electrodes to both ends of the resistance element are provided. The core material is a bundle of insulating fibers, a fixing agent, and a magnetic material. It is characterized by being composed of a body material.

In the method for manufacturing the noise prevention resistor, for example, the liquid magnetic material is dropped onto the substantially central portion of the bundle of insulating fibers which is horizontally spread during conveyance in a predetermined direction, and the dropped portion The insulating fibers are bundled into a columnar shape while being wrapped around, and then the adhesive is impregnated to form the core material. For example, after impregnating the binder of the insulating fiber with the adhesive, the powdery magnetic material is applied to a substantially central portion of the bundle of the insulating fiber which is horizontally spread during conveyance in a predetermined direction. It is characterized in that the core material is formed by converging the insulating fibers into a cylindrical shape while inflowing and enclosing the inflowing portion. For example, when the magnetic material formed into a long thread or rod shape and the bundle of insulating fibers are juxtaposed and conveyed in a predetermined direction, the bundle of insulating fibers spread in the horizontal direction is substantially The core material is formed by bundling the insulating fibers in a columnar shape while wrapping the magnetic material arranged in the central portion and then impregnating the adhesive agent to form the core material. Further, for example, the core material is formed by impregnating a bundle of the insulating fibers, which is being conveyed in a predetermined direction, with the adhesive and the magnetic material. Further, for example, the method further comprises a step of adjusting an impregnated amount of the fixing agent or an impregnated amount of the fixing agent and the magnetic material in the core material.

According to the present invention, a noise prevention resistor having a noise suppression characteristic in a predetermined low frequency region is obtained, and when mounted in an engine ignition device of a vehicle or the like, noise emitted from the engine ignition device is effectively suppressed. it can.

It is an appearance perspective view of the noise prevention resistor concerning the embodiment of the present invention. It is a flow chart which shows the manufacturing process of the resistor concerning an embodiment in a time series. It is a flowchart which shows the core material formation method A in a time series. It is a figure which shows typically the structure of the core material manufacturing apparatus corresponding to the core material formation method A. It is a flowchart which shows the core material formation method B in a time series. It is a figure which shows typically the structure of the core material manufacturing apparatus corresponding to the core material formation method B. It is a flowchart which shows the core material formation method C in a time series. It is a figure which shows typically the structure of the core manufacturing apparatus corresponding to the core forming method C. It is a flowchart which shows the core material formation method D in a time series. It is a figure which shows typically the structure of the core material manufacturing apparatus corresponding to the core material formation method D. It is a figure which shows the core material structure example 1 of the resistor which concerns on embodiment. It is a figure which shows the core material structure example 2 of the resistor which concerns on embodiment. It is a figure which shows the core material structure example 3 of the resistor which concerns on embodiment. It is a figure which shows the core material structural example 4 of the resistor which concerns on embodiment. It is a figure which compares and shows the noise suppression characteristic of the resistor which concerns on embodiment, and the conventional resistor. It is a figure which shows the relationship between the content of the magnetic substance material in the core material of a resistor, and an electrical characteristic.

Embodiments according to the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is an external perspective view of a noise prevention resistor (hereinafter, also simply referred to as a resistor) according to the present embodiment. A resistor 10 shown in FIG. 1 is a resistor that functions as a noise filter, and a fibrous insulator (for example, glass fiber) is bundled to form a rod-shaped (cylindrical) core material 5, and a resistor is provided on the outer periphery thereof. A resistance element (also referred to as a resistor) 2 around which the wire 7 is wound, and cap terminals 3a and 3b that are attached to both ends of the resistance element 2 by press fitting or the like and are electrically connected to the resistance wire 7 are provided.

The resistance wire 7 to be wound around the outer periphery of the core material 5 is, for example, a metal wire such as a nickel-iron (Ni-Fe) wire, a nickel (Ni) wire, or a chromium (Cr) wire, depending on the resistance value of the resistor. To select. Here, the resistance wire 7 having a wire diameter of about several tens μm (for example, 30 to 60 μm) is wound around the core material 5 at a predetermined pitch. As the resistance wire 7, a metal wire may be used as it is, or a coated conductive wire in which a resin coating is formed on the surface of the metal wire may be used.

An insulating coating (also referred to as resin coating) 6 made of resin is formed on the outer peripheral surface of the resistance element 2. Here, a silicone resin or the like is applied and coated on the outer peripheral surface of the core material 5 around which the resistance wire 7 is wound. The insulating coating 6 has a role of preventing rewinding (springback) of the resistance wire.

The core material 5 is composed of a base material made of a glass fiber bundle, a fixing agent (for example, a thermoplastic resin such as epoxy resin), and a magnetic material (for example, ferrite powder, a resin or solvent in which ferrite powder is mixed). To be done. The base material of the core material 5 is configured by bundling a large number of fibrous insulators such as glass, resin, and alumina. As the base material, a glass fiber bundle is suitable from the viewpoint of cost, high heat resistance and flexibility.

The glass fiber bundle is a bundle of a plurality of glass fibers, and the diameter of one fiber is several μm to several tens μm. Therefore, when conveyed in a long state before cutting, the shape of the core material cannot be maintained and the core material is curved. Therefore, the core material 5 made of glass fiber is impregnated with an epoxy resin, a silicone resin or the like and is heated and cured to have a shape. To maintain.

Examples of magnetic materials include iron-based alloys, iron oxides, chromium oxides, manganese oxides, and ferrites (Ni-based, Mn-based), and Ni-based ferrites are preferable from the viewpoint of insulation. As will be described later, the content form of the magnetic material in the resistor is either (1) powder (powder), (2) sintered body of powder and binder, or (3) liquid in which resin or solvent is mixed with powder. There is such a form. Considering the ease of production and the like, a liquid in which powder and resin are mixed or a liquid in which powder and solvent are mixed is desirable.

Each of the cap terminals 3a and 3b has a bottomed tubular shape having an opening, is made of a conductive metal such as iron or stainless, and has a surface plated with copper, nickel or the like. There are the following methods for attaching the cap terminals 3a and 3b to the resistance element 2.

That is, (1) a method of press-fitting and attaching the cap terminals 3a, 3b in which the inner diameter of the opening is slightly smaller than the outer diameter of the resistance element 2 from the axial direction of the resistance element 2, (2) from the axial direction of the resistance element 2 After fitting the cap terminals 3a, 3b whose inner diameter of the opening is slightly larger than the outer diameter of the resistance element 2, there is a method of caulking and attaching part of the outer peripheral surfaces of the cap terminals 3a, 3b.

Next, a manufacturing process of the resistor according to the present embodiment will be described. FIG. 2 is a flowchart showing the manufacturing process of the resistor according to the present embodiment in time series. Step S1 of FIG. 2 is a step of forming the core material of the resistor. The manufacturing process of the core material has several patterns depending on the content form of the magnetic material. These patterns will be described later in detail.

In step S3 of FIG. 2, the resistance wire 7 made of the above-mentioned metal material is continuously wound around the outer periphery of the long rod-shaped core material at a predetermined pitch. In the subsequent step S5, the core material around which the resistance wire is wound is dried to cure the resin.

In step S7, for example, a silicone resin is applied and coated on the surface of the core material wound with the resistance wire and dried and cured to a thickness such that the resistance wire is hidden to form a resin coat. Then, in step S9, the resin coat formed in step S7 is cured.

As described above, the long core material coated with the resistance wire and coated with the resin is cut into a predetermined size by a cutter in step S11 to manufacture individual resistors (winding resistance elements). In a succeeding step S13, the cap terminals formed of the above-mentioned metal and having a cylindrical shape with a bottom are attached from both end surfaces of the resistance element. Here, the cap terminal is mechanically pushed (pressed) from both ends of the resistance element in the axial direction to be fixed. Alternatively, after the cap terminal is press-fitted, the cap terminal may be pressed from the outer peripheral surface thereof to be deformed (caulked) and fixed.

In step S15, the appearance of the resistor manufactured through the above steps is image-inspected, and the resistance value is inspected.

Next, a manufacturing process of the core material used in the resistor according to the present embodiment will be described. Here, the details of the core material forming step in step S1 of FIG. 2, that is, the core material forming method according to the inclusion form (inclusion pattern) of the magnetic material in the core material will be illustrated.

<Core material forming method A>
FIG. 3 is a flowchart showing a core material forming method A as a core material manufacturing process of the resistor according to the present embodiment in time series. Further, FIG. 4 schematically shows the configuration of a core material manufacturing apparatus corresponding to the core material forming method A.

In step S21 of FIG. 3, a plurality of glass fiber bundles in which a large number of glass fibers having a fiber diameter of about several microns are collected are prepared. In step S22, a liquid magnetic material is prepared. Specifically, a magnetic material material in which a magnetic material powder of Ni-based ferrite and a resin are mixed, or a magnetic material material in which a magnetic material powder and a solvent (for example, IPA (isopropyl alcohol), water, etc.) are mixed, Adjust to the desired viscosity.

In step S23, in the core material manufacturing apparatus 20 shown in FIG. 4, the magnetic material supply unit 27 including a nozzle or a dispenser is filled with the liquid magnetic material prepared in step S22. The magnetic material supply unit 27 is filled with the magnetic material in a state in which precipitation of the magnetic material powder is prevented by a stirring pump (not shown).

In step S24, as shown in FIG. 4, the conveying means 23 composed of a plurality of rollers is rotationally driven to convey the glass fibers 21 in the spread state in the direction indicated by the white arrow in FIG. Then, in step S25, the liquid magnetic material 28 is dripped from the magnetic material supply unit 27 to the substantially central portion of the spread glass fiber 21. The magnetic material 28a after the dropping is in a state of extending linearly in the conveying direction according to the conveying speed of the glass fiber 21 and the amount of dropping, as shown in FIG.

In step S26, as shown in FIG. 4, while the glass fiber 21 is narrowed by the focusing portion 24 provided on the downstream side in the vicinity of the portion where the magnetic material is dropped, the portion of the focusing portion 25 where the magnetic material 28 is dropped is removed. The glass fibers 21 are bundled in a columnar shape. As a result, the magnetic material 28 is arranged near the center of the bundled glass fibers, and the glass fibers 21 are bundled so as to wrap it. The bundled glass fibers are immediately dried in the following step S27.

The core material made of glass fiber, which is formed into a long columnar shape in the above-described process and in which the magnetic material is disposed near the center thereof, shifts to the adhesive impregnation process of step S28. That is, the core material dried in step S27 is impregnated with an epoxy resin (adhesive) to form a long rod. More specifically, the epoxy resin (not containing a solvent) adjusted to a low viscosity by temperature control is stored in a metal tank (resin tank), and the core material passes through this tank to form a core material. Impregnate with resin.

In the core material forming method A, depending on whether the resin is not permeated to the central portion of the core material or when the resin is permeated to the central portion of the core material, the inlet of the resin tank (the inlet of the fiber bundle constituting the core material The amount of impregnation of the resin is adjusted by the amount of squeezing, the passage time, and the viscosity of the resin when the core material is put into the tank through the squeezing nozzle provided in FIG.

For example, as shown in FIG. 10, it is possible to adjust the resin so that it does not penetrate into the central portion of the core material by putting the glass fibers in a bundle (collected as the core material) into the resin tank through a throttle nozzle. .. The temperature of the adhesive is controlled by heating the resin tank with a heater or the like.

Therefore, in step S29, it is determined whether the amount of resin impregnated into the core material has reached the adjustment value. If the resin impregnation amount has not reached the adjustment value, the impregnation process of step S28 is continued, and if the resin impregnation amount has reached the adjustment value, the core material forming process ends.

According to the core material forming method A described above, the liquid magnetic material can be stably arranged inside the core material of the resistance element. Further, since there are no complicated steps, it is the simplest manufacturing method as compared with other core material forming methods described later, and according to the present embodiment, without significantly changing the conventional resistor manufacturing steps. It can be applied to the manufacture of resistors.

<Core material forming method B>
FIG. 5 is a flowchart showing a core material forming method B as a core material manufacturing process of the resistor according to the present embodiment in time series. Further, FIG. 6 is a diagram schematically showing a configuration of a core material manufacturing apparatus corresponding to the core material forming method B.

In step S31 of FIG. 5, a plurality of fiber bundles in which a large number of glass fibers having a fiber diameter of about several microns are collected are prepared. In step S32, the powdery magnetic material 38 is filled in the magnetic material supply unit 37, which is provided in the core manufacturing apparatus 30 of FIG.

In step S33, as shown in FIG. 6, the plurality of rollers of the conveying means 33a are rotationally driven to collectively convey a plurality of bundles of glass fibers 31 toward the adhesive impregnated portion 32. In the subsequent step S34, the glass fibers collected as described above are impregnated with the adhesive 39 from the outer periphery thereof in the adhesive impregnating portion 32 in which the adhesive 39 is stored in advance. As the adhesive 39, for example, an epoxy resin is used.

Also in the resin impregnation step of the core material in the core material forming method B, the epoxy resin (containing no solvent) adjusted to have a low viscosity by temperature control is stored in a metal tank (adhesive-impregnated portion 32), The amount of impregnation is adjusted by the time when the core material passes through.

The glass fiber impregnated with the fixing agent as described above is spread by the conveying means 33b in step S35, and the powdery magnetic material supplied from the magnetic material supply unit 37 to the substantially central portion of the expanded glass fiber. Pour material 38. The powdered magnetic material 38a poured into the glass fiber 31 spreads in a streak shape in the transport direction of the glass fiber 31, as shown in FIG.

In step S36, as shown in FIG. 6, the powdery magnetic material 38a is attached by the two focusing portions 35a and 35b provided on the upstream side and the downstream side of the glass fiber 31 in the conveying direction (indicated by the outlined arrow). The glass fibers are bundled into a cylindrical shape so as to wrap around the glass fibers in the above-mentioned portion.

According to the core material forming method B, the powder magnetic material can be stably arranged inside the core material of the resistance element. Further, since the powdery magnetic material material arranged in the core material does not penetrate into the surroundings, the magnetic material material can be easily sealed in the substantially central portion of the core material.

<Core material forming method C>
FIG. 7 is a flowchart showing a core material forming method C as a core material manufacturing process of the resistor according to the present embodiment in time series. Further, FIG. 8 is a schematic diagram showing a configuration of a core material manufacturing apparatus corresponding to the core material forming method C.

In step S41 of FIG. 7, a plurality of fiber bundles in which a large number of glass fibers having a fiber diameter of several microns are collected are prepared. In step S42, a thread-shaped or rod-shaped magnetic material is prepared. For example, a magnetic material powder and a binder (solvent) are mixed and extruded into a long thread (rod) to be molded. Then, in step S43, the magnetic material molded as described above is sintered.

In step S44, as shown in the core material manufacturing apparatus 40 of FIG. 8, the plurality of rollers of the transporting unit 43 are rotationally driven to transport the glass fibers 41 in the direction indicated by the white arrow while the glass fibers 41 are spread. At the same time, the above-mentioned magnetic material 47 molded in a thread shape or a rod shape is conveyed in the direction indicated by the white arrow using the holding means (chuck) 44.

As shown in FIG. 8, the transported glass fibers 41 and the magnetic material 47 are arranged side by side, and the magnetic material 47 is arranged in the focusing portion 45 at a substantially central portion in the axial direction of the core material. The glass fibers 41 are bundled into a cylindrical shape so as to surround the body material 47 (step S45).

In this manner, the epoxy resin (adhesive) is impregnated in the adhesive impregnation step of step S46 with respect to the core material made of glass fiber in which the magnetic material is disposed near the center in the axial direction. Then, in step S47, it is determined whether or not the amount of resin impregnated into the core material has reached the adjustment value. If the amount of impregnation has not reached the adjustment value, the impregnation process of step S46 is continued and impregnation is performed. When the amount reaches the adjustment value, the core material forming process is ended. As a result, the core material is formed into a long rod shape.

Even in the resin impregnation step for the core material in the core material forming method C, the epoxy resin (containing no solvent) adjusted to have a low viscosity by temperature control is stored in a metal tank (resin tank), and the inside of this tank is filled. The amount of impregnation is adjusted depending on the time when the core material passes.

According to the core material forming method C described above, the magnetic material sintered and molded into a thread shape or a rod shape can be arranged inside the core material of the resistance element so that the cross-sectional shape thereof is substantially circular. In addition, by using the sintered and molded magnetic material, in the manufacturing process, it may spill down like a powder magnetic material, or it may penetrate too much into the surroundings like a liquid magnetic material. Absent. Therefore, the magnetic material can be stably arranged in the substantially central portion of the core material.

<Core material forming method D>
FIG. 9 is a flowchart showing a core material forming method D as a core material manufacturing process of the resistor according to the present embodiment in time series. Further, FIG. 10 is a diagram schematically showing a configuration of a core material manufacturing apparatus corresponding to the core material forming method D.

In step S51 of FIG. 9, a plurality of fiber bundles in which a large number of glass fibers having a fiber diameter of about several microns are collected are prepared. In step S52, the powder magnetic material and the resin (epoxy resin) for the adhesive are mixed to adjust the viscosity to a predetermined value.

Next, in step S53, the mixture 59 of the powder magnetic material and the resin is filled in the metal tank (resin tank) 52 provided in the core material manufacturing apparatus 50 of FIG.

In step S54, as shown in FIG. 10, a plurality of rollers of the conveying means 53 are rotationally driven to bundle the glass fibers 51, and in the direction of the resin tank 52 in FIG. 10 (direction indicated by a white arrow). Transport. In the following step S55, the adhesive and the magnetic material are impregnated into the outer periphery of the glass fiber bundled as described above in the resin tank 52.

In step S56, it is determined whether or not the amount of the mixture 59 impregnated into the core material reaches the adjustment value. If the impregnated amount has not reached the adjustment value, the impregnation process of step S55 is continued, and if the impregnated amount has reached the adjustment value, the core material forming process ends.

The method of impregnating the mixture 59 in the resin tank 52 of the core material forming method D is the same as the resin impregnation method described in the core material forming method A. Reference numerals 54a and 54b in FIG. 10 are throttle nozzles not shown in the description of the core material forming method A.

Next, the structure of the core material manufactured by the above-described core material forming methods A to D will be described with reference to FIGS. 11 to 14. As the core material structure of the resistor according to the present embodiment, there are a plurality of structures depending on the content form of the magnetic material described above.

11 to 14, the cross-sectional view indicated by reference numeral (a) is a vertical cross-sectional view when the resistor of FIG. 1 is axially cut along the line X-X', and the reference numeral (b) is used. ) Is a longitudinal sectional view when the resistor of FIG. 1 is cut in a direction orthogonal to the axial direction along the line Y-Y'.

<Core material structure example 1>
FIG. 11 is an example of the core material structure of the resistor according to the present embodiment, in which the magnetic material 15 is contained substantially at the center in the axial direction of the core material, and the adhesive is provided on the outer side in the circumferential direction of the magnetic material 15. A portion 13 of only glass fibers that is not impregnated is provided, and a portion 14 in which the glass fibers are impregnated with a fixing agent is provided outside the portion 13 in the circumferential direction.

As described above, the core material structure shown in FIG. 11 includes the portion 13 that is not impregnated with the adhesive (that is, only the glass fiber) between the magnetic material and the glass fiber impregnated with the adhesive, and is impregnated with the adhesive. If it is not done, the part 13 will not harden, and thus will function as a cushion. As a result, it is possible to sufficiently secure the bending strength in the direction orthogonal to the axis while the core material has flexibility and the compression strength in the axial direction.

<Core material structure example 2>
FIG. 12 is another example of the core material structure of the resistor according to the present embodiment, in which the magnetic material 15 is contained substantially at the center in the axial direction of the core material, and the magnetic material 15 and the core are arranged in the circumferential direction. A portion 16 formed by impregnating glass fiber with a fixing agent is formed between the outer surface of the material and the outer surface.

Unlike the structure shown in FIG. 11, the core material structure shown in FIG. 12 does not include a portion only made of glass fiber that is not impregnated with a fixing agent on the outer side in the circumferential direction of the magnetic material. Therefore, the compressive strength in the axial direction can be increased.

The core material having the structure shown in FIGS. 11 and 12 can be manufactured by the above-described core material forming methods A to C. That is, the core material having the structure shown in FIG. 11 corresponds to an example of the manufacturing method in which the resin is not permeated to the central portion of the core material in the impregnation step in the resin tank. Further, the core material having the structure shown in FIG. 12 corresponds to an example manufactured by a method of permeating the resin to the central portion of the core material in the impregnation step in the resin tank.

<Core material structure example 3>
FIG. 13 is a further example of the core material structure of the resistor according to the present embodiment, in which the glass fiber 13 is impregnated with the magnetic material and the adhesive only in the vicinity of the outer periphery (surface layer portion) of the core material. It has a structure in which 17 is formed. In the core material shown in FIG. 13, the magnetic material is not arranged in the central portion in the axial direction, but the magnetic material is dispersed in the adhesive in the vicinity of the outer periphery of the core material (surface layer portion). Therefore, the glass fiber 13 absorbs the deformation due to the stress, and the structure has high elasticity and flexibility.

<Core material structure example 4>
FIG. 14 shows still another example of the core material structure of the resistor according to the present embodiment, which has a structure in which the magnetic material 18 is contained so as to be substantially uniform over the entire core material. In the example shown in FIG. 14, a mixture of a powder magnetic material and an adhesive (such as an epoxy resin) is impregnated so as to spread over the entire core material, and the magnetic material is dispersed in the adhesive throughout the core material. Has become. With such a structure, the entire core material is firmly fixed, so that the core material is resistant to compression in the axial direction.

The core material having the structure shown in FIGS. 13 and 14 can be manufactured by the core material forming method D described above. That is, the core material shown in FIG. 13 corresponds to a manufacturing method in which the mixture of the powder magnetic material and the fixing agent is not permeated into the glass fiber up to the central portion of the core material. Further, the core material shown in FIG. 14 corresponds to the manufacturing method in which the mixture of the powder magnetic material and the adhesive is permeated into the glass fiber up to the central portion of the core material.

Next, the electrical characteristics of the resistor according to this embodiment and the content of the magnetic material (ferrite) in the core material will be described.

FIG. 15 is a graph showing the results of comparing the electrical characteristics (noise suppression characteristics) of the resistor according to the present embodiment and the conventional resistor (resistor in which the core material does not include a magnetic material). In FIG. 15, the horizontal axis represents frequency (MHz) and the vertical axis represents S21 characteristic (dB). The S21 characteristic is an S parameter indicating the amount of signal attenuation after passing through the noise prevention resistor.

As can be seen from FIG. 15, the resistor according to the present embodiment (example) including a magnetic material in the core material has a resonance point in a lower frequency region than a conventional resistor including no magnetic material, Moreover, the absolute value of S21 is small, that is, it has a good filter characteristic (noise suppression effect).

Regarding the content of the magnetic material in the core material of the resistor according to the present embodiment, the content of the magnetic material in the cross-sectional area of the entire core material including the glass fiber, the adhesive and the magnetic material (cross-sectional area ratio) Was calculated as the content of the magnetic material per unit volume.

According to the invention relating to the wound resistor by the applicant of the present application (Japanese Patent No. 6395581), the glass fiber impregnated with the adhesive, which forms the core material of the resistor, has a cross-sectional area of 5% of the entire core material. If not present, it is difficult to maintain the shape of the core material.

Furthermore, if the core material is made to contain more than 85% of the magnetic material, the proportion of glass fibers in the core material decreases and the proportion of the magnetic material (particles) increases. Therefore, the core material may not be able to withstand the fastening force due to the winding of the resistance wire.

Therefore, it is presumed that the magnetic material can be contained up to 85% of the whole core material except for the glass fiber impregnated with the fixing agent and the glass fiber not impregnated with the fixing agent. That is, the upper limit of the content of the magnetic material is 85% in terms of sectional area ratio.

FIG. 16 shows the relationship between the content (%) of the magnetic material in the core material of the resistor and the electrical characteristics (resonance frequency shift amount (MHz)) of the resistor. Here, the content of the magnetic material was changed and the characteristics were compared. In the plot in the figure, the content of the magnetic material is 1%, 4%, and 19% from the left, and the sample used is the sintered body of the magnetic material (ferrite) located approximately in the center of the core material. 12 is a resistor having the structure of FIG.

It can be seen from FIG. 16 that the resonance frequency of the resistor starts to shift to the low frequency side when the content of the magnetic material is around 5%. Therefore, when the core material contains a magnetic material having a cross-sectional area ratio of 5% or more, target filter characteristics (noise suppression effect) can be expected. Therefore, the content of the magnetic material in the core material of the resistor according to the present embodiment has a lower limit value of 5% in terms of the cross-sectional area ratio of the core material.

From the results of trial production for determining the lower limit of the magnetic material as described above, it was found that the noise suppression effect was improved to a certain extent when the cross-sectional area ratio of the core material was 5% or more, so the lower limit is set to 5%. On the other hand, the optimum value (target value) of the magnetic material was also examined.

As a result, it has been found that the layer of glass fibers (the glass fibers not impregnated with a fixing agent) that serves as a cushion is preferably present in an amount of 30% or more in order to absorb the expansion and contraction of the glass fibers impregnated with the fixing agent. Got In addition, it is estimated that the content of the magnetic material is in the optimum range of 10% to 40% in terms of the cross-sectional area ratio of the core material in consideration of the manufacturing variations and the balance with other materials.

The method of impregnating the core material with the adhesive is not limited to the above-mentioned method, and the following method can be used as another impregnation method.

<Other impregnation method 1>
For example, rotary rollers that rotate in the transport direction sandwiching the core material are provided above and below the core material, and a groove for pouring resin is provided in the rotary roller. Then, the resin is poured into this groove by a dispenser or the like, and the resin is transferred to a portion near the outer periphery of the core material (surface layer of the core material).

<Other impregnation method 2>
When a part of the glass fiber is immersed in the tank in which the resin is stored, the glass fiber is conveyed while being divided into a part impregnated with the resin and a part not impregnated with the resin. Then, at the stage of bundling the glass fibers, the glass fibers impregnated with the resin are bundled so as to be arranged on the outer periphery.

<Other impregnation method 3>
In the step of winding the resistance wire around the core material, the resin is dropped from a dispenser or the like to allow the resin to permeate the surface of the core material. Almost at the same time as the resistance wire winding process, the core material is impregnated with the resin as the fixing agent, so that the manufacturing process can be simplified.

<Other impregnation method 4>
Apply the resin from the top and bottom sides or the left and right sides of the core material with a brush or brush. The resin tank for impregnating the adhesive is not required, and the core material manufacturing apparatus can be downsized.

As described above, in a noise prevention resistor in which a resistance wire is wound around the outer peripheral surface and a pair of cap terminals are attached to both ends of a resistance element made of a core material whose outer peripheral surface is covered with an insulating coating, the core material is insulated. By using a bundle of the characteristic fibers, a fixing agent, and a magnetic material, it is possible to obtain an inductance for ensuring a sufficient attenuation amount (noise suppression effect) in a predetermined frequency range. As a result, the noise prevention resistor functions as a noise filter in which the resonance frequency or the cutoff frequency is shifted within a predetermined frequency range.

Therefore, when the resistor according to the present embodiment is used as a noise prevention resistor for a vehicle engine ignition device, noise emission such as ignition noise from the engine ignition device can be effectively suppressed due to the above-described filter characteristics.

Also, by using glass fiber as the insulating fiber that composes the core material of the noise prevention resistor and using ferrite as the magnetic material, the core material has flexibility and the compressive strength can be increased by impregnating the resin. And the bending strength can be secured.

2 Resistance element (resistor)
3a, 3b Cap terminal 5 Core material 6 Insulation coating (resin coating)
7 Resistance Wire 10 Noise Prevention Resistor 13, 21, 31, 41, 51 Glass Fiber 14, 16 Adhesive Impregnated Parts 15, 18, 28, 38, 47 Magnetic Material 17 Magnetic Material and Adhesive Impregnated Parts 20, 30 , 40, 50 Core material manufacturing device 23, 33a, 43, 53 Conveying means 27, 37 Magnetic material material supplying part 32 Adhesive impregnating parts 35a, 35b, 45 Focusing part 39 Adhesive 52 Resin tank 54a, 54b Throttling nozzle 59 Powder Mixture of magnetic material and resin

Claims (15)

A pair of cap terminals were attached to both ends of a resistance element including an insulating core material, a resistance wire wound around the outer peripheral surface of the core material, and an insulating coating covering the outer peripheral surfaces of the core material and the resistance wire. A noise prevention resistor,
The noise preventing resistor, wherein the core material is composed of a bundle of insulating fibers, a fixing agent, and a magnetic material. The noise prevention resistor according to claim 1, wherein the magnetic material is ferrite, an iron-based alloy, iron oxide, chromium oxide, or manganese oxide. The noise prevention resistor according to claim 2, wherein the ferrite is Ni-based ferrite or Mn-based ferrite. A non-impregnated portion of the adhesive is provided on the outer side in the circumferential direction of the magnetic material, which is disposed substantially at the center of the core material in the axial direction, and an impregnated portion of the adhesive is provided on the outer side of the non-impregnated portion in the circumferential direction. The noise prevention resistor according to any one of claims 1 to 3. The whole area in the circumferential direction outer side of the magnetic material arranged in the substantially central portion of the core material in the axial direction is used as an impregnated portion of the adhesive agent. Noise prevention resistor. The noise prevention resistor according to any one of claims 1 to 3, wherein a surface layer portion of the core material serves as an impregnated portion of the adhesive, and the magnetic material is dispersed in the adhesive. .. The noise prevention resistor according to any one of claims 1 to 3, wherein the whole area of the core material is an impregnated portion of the adhesive, and the magnetic material is dispersed in the adhesive. The noise prevention according to any one of claims 1 to 7, wherein the content of the magnetic material in the core material is 5% or more and 85% or less in terms of a sectional area ratio of the core material. Resistor. 9. The noise prevention resistor according to claim 8, wherein the content of the magnetic material is preferably 10% to 40% in terms of a sectional area ratio of the core material. A step of forming a long core material,
Winding a resistance wire around the outer periphery of the core,
Forming a resistance element by cutting the core material around which the resistance wire is wound into a predetermined size;
Attaching cap electrodes to both ends of the resistance element;
Equipped with
The method of manufacturing a noise preventing resistor, wherein the core material is composed of a bundle of insulating fibers, a fixing agent, and a magnetic material. The liquid magnetic material is dropped onto the substantially central portion of the insulating fiber converging body which is spread horizontally during conveyance in a predetermined direction, and the insulating fibers are bundled into a cylindrical shape while wrapping the dropped portion. 11. The method of manufacturing a noise prevention resistor according to claim 10, wherein the core material is formed by impregnating the adhesive after the step. After impregnating the insulating fiber converging body with the adhesive, the powdery magnetic material is introduced into the substantially central portion of the insulating fiber converging body which is horizontally spread during conveyance in a predetermined direction. 11. The method of manufacturing a noise prevention resistor according to claim 10, wherein the insulating fiber is bundled into a columnar shape to form the core material while wrapping the inflowing portion. When the magnetic material formed in the shape of a long thread or rod and the bundle of insulating fibers are juxtaposed and conveyed in a predetermined direction, the central portion of the bundle of insulating fibers spread horizontally 11. The noise prevention resistor according to claim 10, wherein the core material is formed by bundling the insulating fiber in a cylindrical shape while wrapping the magnetic material arranged in the column, and then impregnating the fixing agent to form the core material. Manufacturing method. 11. The method for manufacturing a noise prevention resistor according to claim 10, wherein the core material is formed by impregnating a bundle of the insulating fibers, which is being conveyed in a predetermined direction, with the adhesive and the magnetic material. .. The noise prevention according to any one of claims 11 to 14, further comprising a step of adjusting an impregnated amount of the fixing agent or an impregnated amount of the fixing agent and the magnetic material in the core material. Method of manufacturing resistor.