JP2009117288A - Fuse resistor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuse resistor that can be made smaller, and is quickly and reliably melt down. <P>SOLUTION: The fuse resistor 1-1 is configured by: housing in a case 70 a fuse element 30 and a plate resistance 10, 10, which are serially connected; and filling a filler 90 therein. The fuse element 30 is rod-shaped, and an outer periphery surface 30a of the fuse element 30 is coated with a tube 31 such that the tube 31 is brought into close-contact therewith. The tube 31 is made of a synthetic resin having elasticity, and is attached to cover the entire exposed outer peripheral surface 30a of the fuse element 30 between both terminals 33 and 33 which are attached to both ends of the fuse element 30. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a power-type resistor, which is a fuse resistor having a structure that blows at a current / voltage of a predetermined value or more.

  Conventionally, this type of fuse resistor is formed by connecting a resistor (3) and a sealed thermal fuse (4) in series as shown in FIG. The case body (1) was filled with an insulating filler (8) and solidified. Further, as shown in FIG. 3 of Patent Document 1, the sealed thermal fuse (4) is configured by installing the thermal fuse (7) in a sealed space by a case (5) and a side plate (5a).

  However, since the conventional fuse resistor uses the sealed thermal fuse (4) having a structure in which the thermal fuse (7) is installed in the space formed in the case (5), the sealed thermal fuse ( 4) The overall external dimensions were large, and the miniaturization of the fuse resistor was hindered. Further, since a space is formed around the thermal fuse (7), the heat conduction from the resistor (3) to the thermal fuse (7) is hindered, and the fuse resistor cannot be cut quickly.

  In order to solve the above problem, the case (5) and the side plate (5a) for sealing the thermal fuse (7) are omitted, and as shown in FIG. The insulating filler 503 may be filled and solidified directly around The fusible body 501 is a cylindrical solder filled with a flux 505 at the center, and metal plate terminals 507 are attached to both ends thereof. If comprised in this way, an exterior case can be reduced in size, the external dimension of the whole fuse resistor can be reduced, and heat transfer from a resistor (not shown) to the fusible body 501 directly through the filler 503. Done quickly.

However, if the filler 503 is directly filled around the soluble body 501 in an exposed state, the fusible body 501 may not be melted reliably. In other words, silicon cement or the like, which is an insulating material with high heat resistance, is usually used as the filler 503, but its surface is rough (uneven and rough), so when the fusible material 501 is melted by heating. As shown by the dotted line in FIG. 11, the melted fusible body 501 is drawn almost half by two to the both terminals 507 made of a metal plate, and the terminals 507 are disconnected. The melted fusible body 501 adhering to the rough inner peripheral surface of the cavity remains attached to the inner peripheral surface, and eventually the ideal fusing shown by the dotted line cannot be performed, as shown by the solid line in FIG. The fusible body 501a attracted to the both terminals 507 remains electrically connected by the fusible body 501b attached to the inner peripheral surface of the filler 503, whereby both terminals 07 while there is a risk that can not be broken.
JP-A-63-53903

  The present invention has been made in view of the above-described points, and an object of the present invention is to provide a fuse resistor that can be miniaturized and that can be quickly and reliably blown as a fuse.

  The invention according to claim 1 of the present invention relates to a fuse resistor in which a fusible body and a resistor are connected in series in a housing portion of a case, and a filler is filled in the housing portion. Is a rod-shaped fuse resistor that is covered with a flexible synthetic resin tube so as to be in close contact with the outer peripheral side surface of the fusible body.

  Invention of Claim 2 of this application is attached so that the said tube may cover the whole outer peripheral side surface where the soluble body between the terminals attached to the both ends of the said soluble body is exposed. The fuse resistor described in 1.

  The invention according to claim 3 of the present application is the fuse resistor according to claim 1 or 2, wherein the fusible body is a cylindrical solder filled with a flux in the center.

According to the first aspect of the present invention, the tube is covered so as to be in close contact with the outer peripheral side surface of the rod-shaped fusible body, and the outer periphery of the tube is filled with the filler so as to be in direct contact. The heat is transferred to the fusible body through the filler and the tube, and therefore the heat of the resistor can be transferred to the fusible body more quickly than in the conventional example having a space between them. A tube is coated around the fusible body that melts at the same time, but the inner peripheral surface of the tube can be easily and smoothly constructed so that the melted fusible body remains attached to the inner peripheral surface of the tube. There is no fear and it is easily sucked to the terminals at both ends and melts. From the above, it is possible to reduce the size, and at the same time, the fuse can be blown quickly and reliably.
Moreover, since the tube made from a synthetic resin which has flexibility is used as a tube, it can coat | cover so that a tube may contact | adhere to the outer peripheral side surface of a soluble body easily and reliably.

  According to the invention described in claim 2, since the entire outer peripheral side surface of the fusible body located between both terminals is covered with the tube, the fusible body hardly touches the filler between the two terminals, thereby further reliably. The fuse resistor can be blown.

  According to the third aspect of the present invention, when the fusible material is melted, the gap in the intermediate portion that is caused by being drawn toward both terminals is not easily negative pressure by the gap in the portion filled with the flux. This can more reliably blow the fuse resistor.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is an exploded perspective view of a fuse resistor 1-1 according to an embodiment of the present invention, and FIG. 2 is a schematic sectional side view of the fuse resistor 1-1. As shown in both figures, the fuse resistor 1-1 accommodates a fusible body 30 and a pair of resistor bodies (hereinafter referred to as “plate resistor plates”) 10 and 10 in series in a housing portion 71 of the case 70. In addition, the storage unit 71 is filled with a filler 90. More specifically, the fuse resistor 1-1 has the fusible body 30 attached to the center of the pair of plate resistor plates 10 and 10 and the opposite side of the pair of plate resistor plates 10 and 10 to which the fusible body 30 is attached. External lead terminals 50 and 50 are respectively attached to the ends, the pair of plate resistor plates 10 and 10 and the fusible body 30 are stored in the storage portion 71 of the case 70, and the storage portion 71 is filled with the filler 90. Configured. At this time, the pair of external lead terminals 50, 50 project outside the case 70. Each component will be described below. In the following description, “upper” means the direction in which the upper terminal 33 shown in FIGS. 1 and 2 of the fusible body 30 is attached as viewed from the fusible body 30, and “lower” means the lower side of the other side. The direction in which the terminal 33 is attached shall be said.

  The pair of plate resistor plates 10 and 10 is formed by meandering a flat (band-like) resistance wire 10A a plurality of times, and at one end thereof (the end portion on the side where both plate resistor plates 10 and 10 approach). Rectangular attachment portions 11 are formed. Terminal attachment portions 13 and 13 are formed at the ends of the pair of plate resistor plates 10 and 10 opposite to the attachment portions 11 and 11, respectively. The plate resistor plates 10 and 10 have a meandering shape having a plurality of linear portions 15 elongated in the vertical direction, and between the end portions of the linear portions 15 so that the linear portions 15 meander in parallel. The bent portion 17 is provided. In this embodiment, the thickness of the plate resistor plates 10, 10 is about 0.1 to 0.2 mm. The material of the plate resistor plates 10 and 10 may be any material as long as it has a predetermined resistance value. For example, Ni (nickel) / Cr (chromium) alloy, Fe (iron) / Cr An alloy, Cu (copper) / Ni alloy, or the like is used. In this embodiment, an Fe · Cr alloy is used, and its melting point is about 1200 to 1400 ° C. In this embodiment, the length, width and thickness of both plate resistor plates 10 and 10 are the same, and the resistance values are the same.

  FIG. 5 is a front view of the fusible body 30 to which the tube 31 and the terminals 33 and 33 are attached. As shown in FIG. 1 and FIG. 1 and FIG. 2, the fusible body 30 has a rod shape, terminals 33 and 33 are attached to both ends of the fusible body 30, and the fusible body 30 between the terminals 33 and 33 is exposed. The tube 31 is covered in close contact with the outer peripheral side surface 30a of the fusible body 30 so as to cover the entire outer peripheral side surface 30a. The fusible body 30 is constituted by a cylindrical solder having a diameter of about 1.0 mm and filled with a flux 35 (see FIG. 6) in the center. The constituent material of the fusible body 30 may be a metal material having a melting point lower than that of the plate resistor plates 10 and 10 (generally a low melting point metal of 500 ° C. or lower), for example, Sn (tin) [99.25%]. A Cu [0.75%] alloy, a Sn [96.5%] · Ag (silver) [3%] · Cu [0.5%] alloy, or the like is used. These are so-called lead-free solders. In this embodiment, a Sn · Cu alloy is used, and its melting point is about 150 to 250 ° C.

  The tube 31 is a flexible synthetic resin tube, and in this embodiment, a silicon tube is used. Of course, other various synthetic resin materials (for example, polyimide) may be used. In short, any synthetic resin material having heat resistance and insulation above the melting temperature of the fusible body 30 may be used. The inner diameter of the tube 31 is formed to be the same as or slightly smaller than the outer diameter of the fusible body 30. In this embodiment, the outer diameter of the fusible body 30 is φ1.0 mm. The inner diameter of 31 is set to φ0.9 to 1.0 mm. Moreover, the tube 31 is formed in the length dimension which covers the whole outer peripheral side surface 30a in which the soluble body 30 between the terminals 33 and 33 attached to the both ends of the soluble body 30 is exposed.

  The terminal 33 is made of a material (metal plate) having a melting point higher than that of the fusible body 30. In this embodiment, Sn-plated Fe (the melting point of Fe is about 1000 ° C.) is used. The material of the terminal 33 is preferably a material whose melting point is closer to the melting point of the plate resistor plates 10, 10 than the melting point of the fusible body 30. The terminal 33 is attached by caulking so as to sandwich the fusible body 30 on the outer periphery in the vicinity of both ends of the fusible body 30. That is, the terminal 33 is configured by integrally connecting a fusible body attaching portion 43 attached to the fusible body 30 and a resistor attaching portion 45 attached to the plate resistor plate 10. The reason for performing the Sn plating is to make it easy to attach the melted soluble body 30 to the terminal 33.

  Next, a method of attaching the tube 31 and the terminals 33 and 33 to the fusible body 30 will be described with reference to FIG. First, as shown in FIG. 3, a fusible body 30, a tube 31, and a pair of terminals 33 and 33 are prepared. The pair of terminals 33 and 33 are held in a rectangular opening 39 provided in a holding plate (lead frame or the like) 37. That is, the resistor attachment portions 45 and 45 of the terminals 33 and 33 are connected to the tips of the pair of connecting portions 41 protruding from the inner periphery of the pair of openings 39 facing each other. Here, FIG. 4 is a cross-sectional view (cross-sectional view taken along the line AA of FIG. 3) of the fusible body mounting portion 43. As shown in FIGS. 3 and 4, the fusible body mounting portion 43 is constructed by bending the left and right side portions of a rectangular flat plate into a substantially U shape in one surface direction, thereby providing a fusible body housing portion 47 at the center thereof. Has been. The fusible body storage portion 47 is formed to have a shape that allows the outer circumference of the fusible body 30 to be loosely gripped (clamped). On the other hand, the resistor mounting portion 45 is formed in a rectangular flat plate shape. Further, the gap dimension L1 between the distal ends of the fusible member mounting portions 43, 43 of both terminals 33, 33 is made substantially the same as the length dimension of the tube 31.

  First, the tube 31 is attached to the center of the outer peripheral side surface 30 a of the fusible body 30. At this time, since the inner diameter dimension of the tube 31 is the same as or slightly smaller than the outer diameter dimension of the fusible body 30, the tube 31 is slightly expanded by the outer peripheral side surface 30 a of the fusible body 30. It is coated so as to be in close contact with 30a. In particular, in this embodiment, since a flexible synthetic resin tube is used as the tube 31, the tube 31 can be easily and reliably coated so as to be in close contact with the outer peripheral side surface 30a. Next, the outer peripheral side surface 30a portion in the vicinity of both ends of the fusible body 30 that protrudes from the tube 31 is mounted in the fusible body housing portions 47 and 47 of the pair of fusible body mounting portions 43 attached to the holding plate 37.・ Pinch and temporarily fix. Then, by caulking the outer periphery of the fusible body mounting portion 43, the fusible body mounting portion 43 is strongly pressed against the outer peripheral side surface 30a of the fusible body 30, and is securely attached electrically and mechanically. And if both the connection parts 41 and 41 are cut | disconnected, as shown in FIG. 5, the soluble body 30 which attached the tube 31 and the terminals 33 and 33 will be completed.

  1 and 2, the external lead terminal 50 is a rod-shaped metal and may be any material that can be fixed to the plate resistor plate 10 by welding or the like. For example, Cu plating or Cu plating is applied to Cu wire or Fe wire. Use what you gave.

  The case 70 has a substantially rectangular and horizontally long thin plate shape, and is provided with a storage portion 71 formed of a substantially rectangular recess having a size capable of storing the pair of plate resistor plates 10 and 10 and the fusible body 30 as they are. Has been. The case 70 may be made of a material having an insulating property and a high heat resistance. In this embodiment, ceramic is used.

The filler 90 is made of a heat-resistant insulating material. In this embodiment, the heat-resistant silicon cement (silica [SiO ₂ ] and silicon varnish [silicone resin] made into a paste with a solvent [xylene etc.], heated at 180 ° C., Cures in 1 hour).

  In order to manufacture the fuse resistor 1-1, the resistor attachment portions 45 and 45 of the terminals 33 and 33 attached to the fusible body 30 are placed on the pair of attachment portions 11 and 11, respectively, for example, by electric welding (spot Are attached by welding or the like, and one end of each of the external lead terminals 50 and 50 is placed on the pair of terminal attachment portions 13 and 13 and attached by, for example, electric welding (spot welding or the like). Next, the plate resistor plates 10 and 10 and the fusible body 30 are housed in the housing portion 71 of the case 70. At this time, the tip portions of the external lead terminals 50, 50 on the side not attached to the plate resistor plates 10, 10 protrude to the outside of the case 70. Then, if the paste-like filler 90 is filled so as to fill the storage portion 71 and heated for a predetermined time to cure the filler 90, the fuse resistor 1-1 is completed.

  In the fuse resistor 1-1 manufactured as described above, when a current / voltage is applied between the external lead terminals 50, 50, the fuse resistor 1-1 acts as a resistor and the both plate resistor plates 10 , 10 are heated. Then, the heat of both plate resistor plates 10 and 10 is immediately transferred to the fusible body 30 through the filler 90, the tube 31, and the fusible body attaching portions 11 and 11. When the fusible body 30 reaches a predetermined temperature (for example, 200 ° C.), the fusible body 30 is melted by the heat, and the external lead terminals 50 and 50 are disconnected.

  Here, FIG. 6 is a schematic cross-sectional view of a main part showing a state of the fusible body 30 embedded in the filler 90. As shown in the figure, in this embodiment, the tube 31 is covered so as to be in close contact with the outer peripheral side surface 30a of the rod-shaped fusible body 30, and the filler 90 is filled so as to be in direct contact with the outer periphery of the tube 31. . Accordingly, the heat of the plate resistor plate 10 is transferred to the fusible body 30 through the filler 90 and the tube 31, and therefore the heat of the plate resistor plate 10 is transferred to the fusible body 30 more quickly than in the conventional example in which there is a space between them. can do. At the same time, the tube 31 is covered around the fusible body 30, but the inner peripheral surface 31a of the tube 31 can be easily and smoothly configured. Accordingly, there is no possibility that the melted fusible body 30 remains attached to the inner peripheral surface 31a of the tube 31 (that is, there is no possibility that the fusible body 501 shown by the solid line in FIG. 11 is in a state), as shown in FIG. Is easily attracted to the terminals 33 and 33 at both ends and melted. As described above, since no space is provided between the fusible body 30 and the filler 90, the fuse resistor 1-1 can be miniaturized, and at the same time, the fuse can be blown quickly and reliably.

  In particular, according to this embodiment, the entire outer peripheral side surface 30a of the fusible body 30 located between the terminals 33 and 33 is covered with the tube 31, so that the fusible body 30 is almost filled between the terminals 33 and 33. The fuse resistor 1-1 can be blown out more reliably without touching 90.

  Furthermore, according to this embodiment, when the fusible body 30 is melted, the gap A1 in the intermediate portion that is generated by being drawn to the both terminals 33, 33 becomes negative pressure by the gap in the portion filled with the flux 35. Therefore, the fuse resistor 1-1 can be blown out more reliably.

  Further, according to the fuse resistor 1-1, since the plate resistor plate 10 is used as the resistor, the terminal 33 of the fusible body 30 can be directly attached thereto, and the manufacture thereof becomes easy. The reason why the terminal 33 is attached to the fusible body 30 and the terminal 33 and the plate resistor plate 10 are welded is that if the fusible body 30 is directly welded to the plate resistor plate 10, the melting points of the two are greatly different. This is because cannot be done well. Therefore, after the terminal 33 made of a material close to the melting point of the plate resistor plate 10 is attached to the fusible body 30, the terminal 33 and the plate resistor plate 10 are welded. As a result, the fusible body 30 can be easily attached to the plate resistor plate 10. Further, since the plate resistor plate 10 is plate-like and thin, the case 70 and the like can be reduced in thickness accordingly, and the fuse resistor 1-1 as a whole can be reduced in thickness.

  FIG. 8 is a schematic sectional side view of a fuse resistor 1-2 according to the second embodiment of the present invention. In the fuse resistor 1-2 shown in the figure, the same or corresponding parts as those of the fuse resistor 1-1 shown in FIGS. Note that matters other than those described below are the same as those in the embodiment shown in FIGS. The fuse resistor 1-2 shown in the figure is different from the fuse resistor 1-1 in that a fusible body 30 is connected in series to the end of one resistor (hereinafter referred to as “plate resistor plate”) 10. Is a point. That is, in this fuse resistor 1-2, one end of one plate resistor plate 10 formed by meandering a flat (band-like) resistance wire 10A a plurality of times is used as a rectangular attachment portion 11, and the other end is provided. The terminal mounting portion 13 is used.

  Then, the resistor attachment portion 45 of one (upper) terminal 33 attached to the fusible body 30 is placed on the attachment portion 11 and attached by, for example, electric welding (spot welding or the like), and the other (lower) terminal 33 is attached. One end of each of the external lead terminals 50 and 50 is placed on the resistor mounting portion 45 (which becomes a “terminal mounting portion” in this embodiment) 45 and the terminal mounting portion 13 of the plate resistor plate 10, respectively, for example, by electric welding. Install by spot welding. Then, the plate resistor plate 10 and the fusible body 30 are stored in the storage portion 71 of the case 70, filled with the paste-like filler 90 so as to fill the storage portion 71, and heated for a predetermined time to cure the filler 90. Then, the fuse resistor 1-2 is completed.

  In the fuse resistor 1-2 as well as the fuse resistor 1-1, if the fusible body 30 reaches a predetermined temperature (for example, 200 ° C.) at the same time, the fusible body 30 is heated. And the external lead terminals 50 and 50 are disconnected. The fusing of the fusible body 30 is performed quickly and reliably as in the above embodiment. In addition, the fuse resistor 1-1 can be miniaturized as in the above embodiment.

  FIG. 9 is a schematic sectional side view of a fuse resistor 1-3 according to the third embodiment of the present invention. In the fuse resistor 1-3 shown in the figure, the same or corresponding parts as those of the fuse resistors 1-1 and 1-2 shown in FIGS. Note that matters other than those described below are the same as those in the embodiment shown in FIGS. The fuse resistor 1-3 shown in the figure stores a fusible body 30 and a resistor (hereinafter referred to as a “winding resistor”) 100 connected in series in a housing portion 71 of the case 70 and a housing portion. 71 is filled with a filler 90. More specifically, in the fuse resistor 1-3, the conducting wire 101 attached to one end (upper side) of the winding resistor 100 is bent at a substantially right angle, and the bent tip side portion is attached to the fusible body 30. The resistor attachment portion 45 of one (upper) terminal 33 is attached by spot welding or the like, and the resistor attachment portion of the other (lower) terminal 33 attached to the fusible member 30 (in this embodiment, “terminal attachment”). The conductive wire 105 is attached to 45 by spot welding or the like, and the conductive wire 103 is attached to the other end (lower side) of the winding resistor 100 by spot welding or the like. The portion is stored in the storage portion 71 of the case 70, and the storage portion 71 is further filled with a filler 90. At this time, the pair of conductive wires 103 and 105 project outside the case 70 as external lead terminals. The conducting wires 101, 103, 105 are made of metal rods, and for example, Cu wires or Fe wires obtained by applying Cu plating (or coating), etc. are used.

  The winding resistor 100 is configured by winding resistance wires around an insulating and columnar core material and attaching metal plate terminals to both ends of the core material. The conductors 101 and 103 are connected to these terminals. It is attached by spot welding. On the other hand, the shape and structure of the fusible body 30 to which the tube 31 and the terminals 33 and 33 are attached are the same as those of the above embodiments. The case 70 and the filler 90 are also made of the same material as that of the above embodiments, although the shapes are different.

  Also in the fuse resistor 1-3 manufactured as described above, when a current / voltage is applied between the conductive wires 103 and 105, the fuse resistor 1-3 acts as a resistor and the winding resistor 100 Is heated. The heat of the winding resistor 100 is immediately transferred to the fusible body 30 through the filler 90, the tube 31, and the conductive wire 101. When the fusible body 30 reaches a predetermined temperature (for example, 200 ° C.), the fusible body 30 is melted by the heat and the conductors 103 and 105 are disconnected. The fusing of the fusible body 30 is performed quickly and reliably as in the above embodiment. In addition, the fuse resistor 1-3 can be miniaturized as in the above embodiment.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the technical idea described in the claims and the specification and drawings. Is possible. It should be noted that any shape, structure, or material not directly described in the specification and drawings is within the scope of the technical idea of the present invention as long as the effects and advantages of the present invention are exhibited. For example, plates having various shapes and structures other than those shown in the above embodiments may be used as the plate resistor plate 10, the fusible body 30, the case 70, the filler 90, and the winding resistor 100. For example, the fusible body 30 does not necessarily have a structure in which the flux 35 is filled in the center, and the tube 31 has an outer peripheral side surface where the fusible body 30 between the terminals 33 and 33 attached to both ends of the fusible body 30 is exposed. You may attach so that a part of 30a may be covered. Further, the various assembling procedures of the fuse resistors 1-1 to 1-3 are merely examples, and it goes without saying that other various assembling procedures may be used. In addition, the resistor is not limited to those of the above-described embodiments, and other various structures of resistors (for example, a metal oxide film resistor formed by forming a resistance film made of an oxide film on the surface of an insulating core) It may be.

It is a disassembled perspective view of the fuse resistor 1-1. It is a schematic sectional side view of the fuse resistor 1-1. It is explanatory drawing of the attachment method of the tube 31 and the terminals 33 and 33 to the soluble body 30. FIG. It is sectional drawing (AA sectional view taken on the line of FIG. 3) of the soluble body attaching part 43. It is a front view of the soluble body 30 which attached the tube 31 and the terminals 33 and 33. FIG. FIG. 3 is a schematic cross-sectional view of a main part showing a fusible body 30 embedded in a filler 90. It is a principal part schematic sectional drawing which shows the state which the meltable body 30 cut out. It is a schematic sectional side view of the fuse resistor 1-2. It is a schematic sectional side view of the fuse resistor 1-3. It is a principal part schematic sectional drawing which shows the soluble body 501 embed | buried in the filler 503. FIG. It is a principal part schematic sectional drawing which shows the state at the time of the meltable body 501 fusing.

Explanation of symbols

1-1 Fuse resistor 10 Plate resistor plate (resistor)
30 Fusible body 30a Outer peripheral surface 31 Tube 35 Flux 50 External lead terminal 70 Case 71 Storage part 90 Filling material 1-2 Fuse resistor 1-3 Fuse resistor 100 Winding resistor (resistor)

Claims (3)

A fuse resistor in which a fusible body and a resistor are connected in series is housed in a housing portion of the case, and a filling material is filled in the housing portion.
A fuse resistor characterized in that the fusible body has a rod shape and is covered with a flexible synthetic resin tube so as to be in close contact with the outer peripheral side surface of the fusible body.   2. The fuse resistor according to claim 1, wherein the tube is attached so as to cover an entire outer peripheral side surface where a soluble body between terminals attached to both ends of the soluble body is exposed.   3. The fuse resistor according to claim 1, wherein the fusible body is a cylindrical solder filled with a flux in the center.

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