Resistor and its manufacturing method

Abstract

To provide a resistor capable of improving heat dissipation property, and a method for manufacturing the same.SOLUTION: A resistor 1 includes a resistance body part 2, and a mold resin 3 in which the resistance body part 2 is embedded. The mold resin 3 contains a filler 32 having thermal conductivity higher than that of a base material resin 31. A method for manufacturing a resistor 1 includes the steps of: manufacturing a resistance body part 2; and installing the resistance body part 2 in a mold 4, injecting a molten raw material constituting a mold resin 3 into the mold 4, curing the raw material, and molding a mold resin 3.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a resistor and a method for manufacturing the same. [Background technology]

[0002] Patent Document 1 discloses a cement resistor that includes a case, a resistor placed in the case, and a cement material that is filled in the case and seals the resistor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-38275 Summary of the Invention [Problem to be solved by the invention]

[0004] In the cement resistor described in Patent Document 1, heat generated in the resistor is transmitted through the cement and the case in order, and then dissipated to the outside of the cement resistor, but there is room for improvement in terms of improving heat dissipation.

[0005] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a resistor capable of improving heat dissipation properties and a method for manufacturing the same. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, the present invention provides a resistor comprising a resistor body and a molded resin in which the resistor body is embedded, wherein the molded resin contains a filler having a higher thermal conductivity than the base resin.

[0007] In addition, in order to achieve the above-mentioned object, the present invention provides a method for manufacturing a resistor, comprising the steps of: manufacturing the resistor body; placing the resistor body in a mold; injecting molten raw materials that constitute the molded resin into the mold; and hardening the raw materials to form the molded resin. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a resistor capable of improving heat dissipation and a method for manufacturing the same. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 2 is a perspective view of a resistor according to the first embodiment. [Figure 2] FIG. 2 is a cross-sectional view of a resistor according to the first embodiment. [Figure 3] FIG. 3 is an enlarged schematic diagram of the area circled by the dashed line in FIG. 2. [Figure 4] FIG. 2 is a cross-sectional view showing an example of a state in which the resistor according to the first embodiment is used. [Figure 5] FIG. 3 is a cross-sectional view illustrating a mold and a resistor before clamping, illustrating a method for manufacturing a resistor according to the first embodiment. [Figure 6] FIG. 2 is a cross-sectional view illustrating a clamped mold and a resistor, illustrating a method for manufacturing a resistor according to the first embodiment. [Figure 7] FIG. 3 is a cross-sectional view illustrating a state in which a molding resin is molded in a mold, illustrating a method for manufacturing a resistor according to the first embodiment. [Figure 8] FIG. 10 is a cross-sectional view showing an example of a state in which a resistor is used in a second embodiment. [Figure 9] FIG. 10 is a perspective view of a resistor according to a third embodiment. [Figure 10] FIG. 10 is a cross-sectional view of a resistor according to a third embodiment. [Figure 11]FIG. 10 is a cross-sectional view illustrating a mold and a resistor before clamping, illustrating a method for manufacturing a resistor according to a third embodiment. [Figure 12] FIG. 10 is a cross-sectional view illustrating a clamped mold and a resistor, illustrating a method for manufacturing a resistor according to a third embodiment. [Figure 13] FIG. 10 is a perspective view of a resistor according to a fourth embodiment. [Figure 14] FIG. 10 is a cross-sectional view of a resistor according to a fourth embodiment. [Figure 15] FIG. 10 is a cross-sectional view illustrating a mold and a resistor before clamping, illustrating a method for manufacturing a resistor according to a fourth embodiment. [Figure 16] FIG. 10 is a cross-sectional view illustrating a clamped mold and a resistor, illustrating a method for manufacturing a resistor according to a fourth embodiment. [Figure 17] FIG. 11 is a perspective view of a resistor according to a fifth embodiment. [Figure 18] FIG. 10 is a cross-sectional view of a resistor according to a fifth embodiment. [Figure 19] FIG. 13 is a cross-sectional view illustrating a clamped mold and a resistor, illustrating a method for manufacturing a resistor according to a fifth embodiment. [Figure 20] FIG. 13 is a perspective view of a resistor according to a sixth embodiment. [Figure 21] FIG. 13 is a plan view of a resistor according to a sixth embodiment. [Figure 22] FIG. 13 is a cross-sectional view of a resistor according to a sixth embodiment. [Figure 23] FIG. 13 is a cross-sectional view illustrating a clamped mold and a resistor, illustrating a method for manufacturing a resistor according to a sixth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] [First embodiment] A first embodiment of the present invention will be described with reference to Figures 1 to 7. The embodiment described below is shown as a preferred specific example for carrying out the present invention, and although various technically preferable technical matters are specifically exemplified, the technical scope of the present invention is not limited to this specific embodiment.

[0011] (Resistor 1) Fig. 1 is a perspective view of a resistor 1 according to this embodiment. Fig. 2 is a cross-sectional view of the resistor 1 according to this embodiment. The resistor 1 includes a resistor body 2 and a mold resin 3 in which the resistor body 2 is embedded.

[0012] In this embodiment, the resistor body 2 includes a resistor element 21, a pair of cap electrodes 22 fitted to both ends of the resistor element 21, and a pair of lead wires 23 connected to the pair of cap electrodes 22, respectively. In this embodiment, the resistor body 2 is a so-called wire-wound resistor element. The resistor element 21 includes an electrically insulating core material 211 and a wire 212 wound helically around the outer periphery of the core material 211. The core material 211 is formed by forming an electrically insulating material such as ceramic into a cylindrical shape. The wire 212 is formed by a conductive wire such as nichrome wire. Note that, although the resistor body 2 is a wire-wound resistor in this embodiment, the present invention is not limited thereto and may be a ceramic resistor without a wire 212, such as a cylindrically formed conductive ceramic.

[0013] The cap electrode 22 is made of a conductive metal or the like. The cap electrode 22 has a disk-shaped bottom portion 221 perpendicular to the longitudinal direction of the resistor element 21 and a cylindrical side portion 222 extending from the periphery of the bottom portion 221 toward the center of the resistor element 21 in the longitudinal direction of the resistor element 21. The cap electrode 22 is open on the side portion 222 opposite the bottom portion 221. Note that hereinafter, the longitudinal direction of the resistor element 21 may also be referred to as the element longitudinal direction X. The pair of cap electrodes 22 are fitted to both ends of the resistor element 21 in the element longitudinal direction X. When fitted to the resistor element 21, the side portion 222 is in electrical contact with the winding 212 of the resistor element 21, thereby electrically connecting the cap electrode 22 to the winding 212. Note that when the pair of cap electrodes 22 are fitted to the resistor element 21, the cap electrodes 22 and the winding 212 may be connected by welding or the like. The pair of cap electrodes 22 are connected to different lead wires 23 .

[0014] The lead wire 23 is joined by welding or the like to the surface of the bottom 221 of the cap electrode 22 opposite to the resistance element 21 side. The lead wire 23 is made of a conductor such as a tin-plated conductor.

[0015] The molding resin 3 is molded so as to embed the resistor body 2 while exposing the ends of the pair of lead wires 23. The molding resin 3 is formed in the shape of a long rectangular pillar in the longitudinal direction X of the element.

[0016] FIG. 3 is a schematic diagram showing an enlarged view of the area circled by a dashed line in FIG. 2. As shown in FIG. 3, the mold resin 3 contains an electrically insulating base resin 31 and a thermally conductive filler 32. The base resin 31 is made of an electrically insulating resin such as PPS (polyphenylene sulfide) resin or epoxy resin. The filler 32 can be made of, for example, metal powder or ceramic powder, and more specifically, powder of aluminum oxide, boron nitride, aluminum nitride, or the like. Note that, for convenience, the filler 32 is shown as a circle in FIG. 3, but the shape of the filler 32 is not limited to this.

[0017] By including thermally conductive filler 32 in mold resin 3, the thermal conductivity of the entire mold resin 3 is improved, and the temperature inside resistor 1 is prevented from rising to a high temperature. In this embodiment, the thermal conductivity of mold resin 3 is equal to or higher than that of cement, for example, 2 W / (m·K) or higher, and preferably 3 W / (m·K) or higher. The thermal conductivity of mold resin 3 can also be 10 W / (m·K) or lower.

[0018] A typical cement resistor is constructed by filling a case with cement, which adheres tightly to the case. The resistor 1 of this embodiment adheres tightly to the molded resin 3 and does not have a case to house the molded resin 3. This prevents the resistor 1 from becoming too large. When using the resistor 1, it is possible to assemble the resistor 1 into a case manufactured separately from the resistor 1. Even in this case, the resistor 1 is removably attached to the case, but the resistor 1 itself, which does not have a case, is formed to be small.

[0019] FIG. 4 is a cross-sectional view showing an example of a state in which the resistor 1 is used. The resistor 1 is attached to, for example, a circuit board 10. In this case, a pair of lead wires 23 are bent so as to be inserted into through-holes 101 in the circuit board 10 and connected to the circuit board 10 using solder 12 or the like. The resistor 1 can also be installed in, for example, an automobile engine compartment. In this case, the resistor 1 may be installed in a motor wiring connecting a stator coil of a motor to a terminal block of the motor, forming a snubber circuit for suppressing surge voltages. When the resistor 1 is installed in a high-temperature environment such as an engine compartment, the ambient temperature of the resistor 1 becomes high, requiring the resistor 1 to have high heat dissipation properties. In this case, the resistor 1 of this embodiment is preferably used. When the resistor 1 is attached to the circuit board 10, at least one of four faces of the rectangular column-shaped molded resin 3 parallel to the longitudinal direction X of the element faces the circuit board 10. The heat of the resistor 1 is transferred through the mold resin 3 and dissipated to the air around the resistor 1, and is also dissipated from the circuit board 10 through the mold resin 3 or the lead wires 23.

[0020] The resistor 1 may be mounted on a mounting member other than the circuit board 10. In this case, for example, if the surface of the mounting member that comes into contact with the resistor 1 has a non-planar shape, such as a curved surface, the surface of the molded resin 3 that comes into contact with the mounting member may be shaped to conform to the non-planar shape. The molded resin 3 may also have a shape other than a rectangular columnar shape.

[0021] (Method for manufacturing resistor 1) Next, an example of a manufacturing method of the resistor 1 will be described with reference to Fig. 5 to Fig. 7. Fig. 5 is a cross-sectional view showing the mold 4 and the resistor 1 before clamping. Fig. 6 is a cross-sectional view showing the mold 4 and the resistor 1 after clamping. Fig. 7 is a cross-sectional view showing a state in which the mold resin 3 has been molded in the mold 4.

[0022] In manufacturing the resistor 1, first, the resistor body 2 is manufactured. The resistor body 2 can be manufactured in the same manner as in the manufacturing method of a normal wire-wound resistor.

[0023] 5 and 6, the resistor body 2 is set in a mold 4 for molding the molding resin 3. The mold 4 has an upper mold 41 and a lower mold 42 that are aligned in a direction perpendicular to the longitudinal direction X of the element. A pair of lead gripping grooves 43 for positioning and gripping a pair of leads is formed on the mating surfaces of the upper mold 41 and the lower mold 42. By clamping the upper mold 41 and the lower mold 42 together, the pair of lead wires 23 of the resistor body 2 are gripped by the mold 4.

[0024] Then, a molten raw material that will become the molded resin 3 is injected into the cavity 40 in the mold 4 in which the resistor body 2 is arranged and hardened, thereby forming the molded resin 3 as shown in Fig. 7, and producing the resistor 1. The raw material of the molded resin 3 is a molten resin that will become the base resin (see reference numeral 31 in Fig. 3) with a filler (see reference numeral 32 in Fig. 3) dispersed in it. After the molded resin 3 is formed, the pair of lead wires 23 exposed from the molded resin 3 may be bent to make it easier to connect the resistor 1 to a connection destination.

[0025] (Functions and Effects of the First Embodiment) In this embodiment, the molding resin 3 in which the resistor body 2 is embedded contains filler 32 having a higher thermal conductivity than the base resin 31. Therefore, the heat dissipation of the resistor 1 can be improved.

[0026] The thermal conductivity of the molded resin 3 is 3 W / (m·K) or more and 10 W / (m·K) or less. By making the thermal conductivity of the molded resin 3 3 W / (m·K) or more, the heat dissipation of the resistor 1 can be improved. By making the thermal conductivity of the molded resin 3 10 W / (m·K) or less, the cost of the molded resin 3 can be reduced and the moldability can be improved. In order to increase the thermal conductivity of the molded resin 3, it is necessary to include a large amount of filler 32. However, the more filler 32 added, the higher the cost of the molded resin 3 becomes, and the worse the fluidity of the molten raw material that becomes the molded resin 3 becomes, which tends to deteriorate the moldability of the molded resin 3. Therefore, by making the thermal conductivity of the molded resin 3 10 W / (m·K) or less, the cost of the molded resin 3 can be reduced and the moldability can be improved.

[0027] As described above, according to the present embodiment, it is possible to provide a resistor capable of improving heat dissipation and a method for manufacturing the same.

[0028] [Second embodiment] FIG. 8 is a cross-sectional view showing a state in which the resistor 1 of this embodiment is used.

[0029] In this embodiment, the position of the resistor body 2 within the molded resin 3 is devised. Here, the outer peripheral surface of the molded resin 3 facing the circuit board 10 is referred to as the reference plane 30, and the direction perpendicular to the reference plane 30 is referred to as the vertical direction Z. The side toward which the reference plane 30 faces is referred to as the lower side, and the opposite side is referred to as the upper side. The expressions "upper" and "lower" are merely for convenience and do not limit the orientation of the resistor 1 relative to the vertical direction, for example, when the resistor 1 is in use. In the vertical direction Z, the length L1 from the reference plane 30 to the lower end position of the resistive element 21 is shorter than the length L2 from the upper surface of the molded resin 3 to the upper end position of the resistive element 21. The ends of the pair of lead wires 23 are bent downward and connected to a connection destination, such as a through-hole 101, of the circuit board 10.

[0030] Other configurations of this embodiment are the same as those of the first embodiment. It should be noted that, among the symbols used in the second and subsequent embodiments, the same symbols as those used in the previously described embodiments represent the same components, etc. as those in the previously described embodiments, unless otherwise specified.

[0031] (Functions and Effects of the Second Embodiment) In this embodiment, the distance from the resistive element 21 to the mounting member, such as the circuit board 10, of the resistor 1 can be shortened via the mold resin 3, thereby shortening the heat transfer distance from the resistive element 21 to the mounting member, thereby improving heat dissipation from the resistive element 21 to the mounting member. In addition, the second embodiment has the same functions and effects as the first embodiment.

[0032] [Third embodiment] Fig. 9 is a perspective view of the resistor 1 in this embodiment, and Fig. 10 is a cross-sectional view of the resistor 1 in this embodiment.

[0033] (Resistor 1) In this embodiment, the resistor body 2 further includes a pair of sleeve members 24. Each of the pair of sleeve members 24 is formed in a substantially cylindrical shape, and is arranged so that different lead wires 23 are inserted therethrough. The pair of sleeve members 24 have shapes symmetrical to each other in the element longitudinal direction X.

[0034] The sleeve member 24 has a cylindrical small diameter portion 241 and a large diameter portion 242 that protrudes radially outward from the small diameter portion 241 at an end of the small diameter portion 241 closer to the cap electrode 22. The large diameter portion 242 of the sleeve member 24 abuts against the bottom portion 221 of the cap electrode 22, and the large diameter portion 242 and the cap electrode 22 are joined by welding or the like. In this embodiment, the sleeve member 24, which is separate from the cap electrode 22, is joined to the bottom portion 221 of the cap electrode 22, but the present invention is not limited to this, and the sleeve member 24 may be formed integrally with the cap electrode 22.

[0035] In this embodiment, the sleeve member 24 is formed to have higher rigidity than the lead wire 23. The sleeve member 24 is made of a metal, alloy, resin, or the like that is higher in rigidity than the lead wire 23. For example, the sleeve member 24 is made of phosphor bronze or the like with a tin-plated surface. Although not shown in the drawings, the sleeve member 24 may be configured so that its minimum thickness is larger than the diameter of the lead wire 23. In the configuration of the sleeve member 24 in this embodiment, the minimum thickness of the sleeve member 24 is the thickness of the small diameter portion 241 of the sleeve member 24.

[0036] The portion of the sleeve member 24 on the cap electrode 22 side is embedded in the mold resin 3, and the portion on the opposite side to the cap electrode 22 side is exposed from the mold resin 3. In this embodiment, only a part of the small diameter portion 241 of the sleeve member 24 is exposed from the mold resin 3. Note that, for example, a configuration in which the entire sleeve member 24 is exposed may also be employed. The rest is the same as in the first embodiment.

[0037] (Method for manufacturing resistor 1) Next, an example of a manufacturing method for the resistor 1 of this embodiment will be described with reference to Figures 11 and 12. Figure 11 is a cross-sectional view showing the mold 4 and the resistor 1 before clamping. Figure 12 is a cross-sectional view showing the mold 4 and the resistor 1 after clamping.

[0038] First, the resistor main body 2 is manufactured except for the sleeve member 24. Then, the lead wire 23 is inserted into the sleeve member 24, and the large diameter portion 242 of the sleeve member 24 is brought into contact with the bottom portion 221 of the cap electrode 22. Next, the sleeve member 24 and the cap electrode 22 are joined by welding or the like. This completes the resistor main body 2.

[0039] 11 and 12, the resistor body 2 is set in a mold 4. The mold 4 has an upper mold 41 and a lower mold 42 that are aligned in a direction perpendicular to the longitudinal direction X of the element. The upper mold 41 and the lower mold 42 each have a pair of sleeve gripping grooves 44 formed on their mating surfaces for positioning and gripping the pair of sleeve members 24. By clamping the upper mold 41 and the lower mold 42 together, the pair of sleeve members 24 of the resistor body 2 are gripped by the mold 4.

[0040] Then, the molten raw material that will become the molded resin 3 is injected into the cavity 40 in the mold 4 in which the resistor main body 2 is arranged and hardened, thereby forming the molded resin 3 and producing the resistor 1.

[0041] In this embodiment, the sleeve member 24 and the cap electrode 22 are welded to each other, but they do not have to be welded to each other. In this case, in the resistor body 2 before being molded, the sleeve member 24 is movable relative to the lead wire 23, but in a state where the pair of sleeve members 24 of the resistor body 2 are held by the upper mold 41 and the lower mold 42, the sleeve member 24 is immovable relative to the lead wire 23. Then, when the mold resin 3 is molded, the sleeve member 24 is integrated with the mold resin 3. The rest is the same as in the first embodiment.

[0042] (Functions and Effects of the Third Embodiment) The resistor 1 of this embodiment has a pair of sleeve members 24, and a portion of each of the pair of sleeve members 24 is exposed from the molded resin 3. Therefore, the sleeve members 24 can protect the lead wires 23 exposed from the molded resin 3. Furthermore, when molding the molded resin 3, the molded resin 3 can be molded while holding the sleeve members 24 in the mold 4 used to mold the molded resin 3. Here, if the mold 4 is configured to hold the lead wires 23, there is a risk that the lead wires 23 will deform if the lead wires 23 have low rigidity. On the other hand, according to this embodiment, since the pair of sleeve members 24 can be held by the mold 4, deformation of the pair of lead wires 23 can be suppressed when the mold 4 is closed. In addition, the second embodiment has the same functions and effects as the first embodiment.

[0043] [Fourth embodiment] Fig. 13 is a perspective view of the resistor 1 in this embodiment, and Fig. 14 is a cross-sectional view of the resistor 1 in this embodiment.

[0044] (Resistor 1) In this embodiment, a portion of each of the pair of cap electrodes 22 constitutes a cap exposed portion 223 that is exposed from the mold resin 3. In this embodiment, only the ends of the pair of cap electrodes 22 that are farther from each other constitute the cap exposed portion 223, and the other portions are buried in the mold resin 3. The cap exposed portion 223 is constituted by a bottom portion 221 and a portion of the side portion 222 on the bottom 221 side. Note that this is not limiting, and for example, the entire cap electrode 22 may constitute the cap exposed portion 223, but it is preferable that the resistance element 21 is protected by being covered with the mold resin 3. The rest is the same as in the first embodiment.

[0045] (Method for manufacturing resistor 1) Next, an example of a manufacturing method for the resistor 1 of this embodiment will be described with reference to Figures 15 and 16. Figure 15 is a cross-sectional view showing the mold 4 and the resistor 1 before clamping. Figure 16 is a cross-sectional view showing the mold 4 and the resistor 1 after clamping.

[0046] First, the resistor body 2 is manufactured. Next, as shown in FIGS. 15 and 16 , the resistor body 2 is set in a mold 4 for molding the molding resin 3. The mold 4 has an upper mold 41 and a lower mold 42 that are aligned in a direction perpendicular to the element longitudinal direction X. A pair of cap holding grooves 45 for positioning and holding a pair of cap electrodes 22 is formed on the mating surfaces of the upper mold 41 and the lower mold 42. By clamping the upper mold 41 and the lower mold 42 together, the pair of cap electrodes 22 of the resistor body 2 are held in the mold 4.

[0047] Then, the molten raw material that will become the molded resin 3 is injected into the cavity 40 in the mold 4 in which the resistor main body 2 is arranged and hardened, thereby forming the molded resin 3 and producing the resistor 1. The rest is the same as in the first embodiment.

[0048] (Functions and Effects of the Fourth Embodiment) In this embodiment, at least a portion of each of the pair of cap electrodes 22 is exposed from the mold resin 3. This makes it easier to reduce the amount of mold resin 3 used, thereby enabling the resistor 1 to be made lighter and more compact overall. Furthermore, when molding the mold resin 3, it is possible to mold the mold resin 3 while holding the pair of cap electrodes 22 with the mold 4 used to mold the mold resin 3. This makes it possible to prevent the pair of lead wires 23 from being deformed when the mold 4 is closed.

[0049] Moreover, only a portion of each of the pair of cap electrodes 22 is exposed from the mold resin 3. That is, each of the pair of cap electrodes 22 has a portion embedded in the mold resin 3 and a portion exposed from the mold resin 3. Therefore, as described above, it is possible to hold the pair of cap electrodes 22 with the mold 4, and by embedding a portion of the cap electrodes 22 in the mold resin 3, it is possible to diffuse heat from the cap electrodes 22 to the mold resin 3, thereby improving the heat dissipation of the entire resistor 1. In addition, the second embodiment has the same functions and effects as the first embodiment.

[0050] [Fifth embodiment] Fig. 17 is a perspective view of the resistor 1 in this embodiment, and Fig. 18 is a cross-sectional view of the resistor 1 in this embodiment.

[0051] (Resistor 1) This embodiment is an embodiment that includes plate terminals 25. In this embodiment, a pair of plate terminals 25 are connected to the pair of cap electrodes 22, respectively. Note that, unlike the first embodiment, the resistor 1 of this embodiment does not include lead wires (see reference numeral 23 in FIGS. 1 and 2).

[0052] The plate terminals 25 are made of a conductor such as a metal or alloy having a higher thermal conductivity than the mold resin 3. The plate terminals 25 are formed in a plate shape perpendicular to the longitudinal direction X of the element and are connected to the open end of the side portion 222 of the cap electrode 22. The pair of plate terminals 25 are formed to have substantially the same shape. In this embodiment, the plate terminals 25 are formed integrally with the cap electrode 22. For example, the cap electrode 22 and the plate terminals 25 can be formed simultaneously by pressing a single plate. However, this is not a limitation, and the plate terminals 25 and the cap electrode 22 may be formed separately. In this case, the plate terminals 25 and the cap electrode 22 may be connected by, for example, welding or the like.

[0053] The plate terminal 25 has a protrusion 250 protruding in a vertical direction Z perpendicular to the element longitudinal direction X. In this embodiment, the direction perpendicular to both the element longitudinal direction X and the vertical direction Z is referred to as the horizontal direction Y. The side of the plate terminal 25 from which the protrusion 250 protrudes is referred to as the lower side, and the opposite side is referred to as the upper side. Note that the expressions "upper" and "lower" are for convenience and do not limit the orientation of the resistor 1 relative to the vertical direction when the resistor 1 is in use, for example. The width of the protrusion 250 in the horizontal direction Y is smaller than the width of the first terminal portion in the horizontal direction, and the protrusion 250 extends downward from approximately the center of the first terminal portion in the horizontal direction Y. The entire first terminal portion of the plate terminal 25 and the upper end of the protrusion 250 are disposed within the molded resin 3, and most of the protrusion 250 is exposed from the molded resin 3. The resistor 1 is electrically connected to a circuit board or the like via the protrusions 250 of the pair of plate terminals 25 exposed from the molded resin 3. The rest is the same as in the first embodiment.

[0054] (Method for manufacturing resistor 1) Next, an example of a method for manufacturing the resistor 1 of this embodiment will be described with reference to Fig. 19. Fig. 19 is a cross-sectional view showing the clamped mold 4 and the resistor 1.

[0055] First, the resistor body 2 is manufactured. Next, the resistor body 2 is set in a mold 4 for molding the molded resin 3. The mold 4 has an upper mold 41 and a lower mold 42 that can be aligned in the vertical direction Z. The lower mold 42 is located below the resistor body 2 and has insertion holes 421 for inserting the protrusions 250. The resistor body 2 is positioned relative to the clamped upper mold 41 and lower mold 42 by inserting the protrusions 250 of the pair of plate terminals 25 into the pair of insertion holes 421.

[0056] Then, the molten raw material that will become the molded resin 3 is injected into the cavity 40 in the mold 4 in which the resistor main body 2 is arranged and hardened, thereby forming the molded resin 3 and producing the resistor 1. The rest is the same as in the first embodiment.

[0057] (Functions and Effects of the Fifth Embodiment) In this embodiment, at least a portion of each of the pair of plate terminals 25 is exposed from the molded resin 3. By exposing the plate terminals 25, which are relatively easy to ensure rigidity, from the molded resin 3 in this way, it is possible to prevent the plate terminals 25 exposed from the molded resin 3 from unintentionally deforming. Furthermore, when molding the molded resin 3, it is possible to mold the molded resin 3 while holding the plate terminals 25, which are relatively easy to ensure rigidity, in the mold 4 for molding the molded resin 3. In addition, the second embodiment has the same functions and effects as the first embodiment.

[0058] [Sixth embodiment] Fig. 20 is a perspective view of the resistor 1 in this embodiment, Fig. 21 is a plan view of the resistor 1 in this embodiment, and Fig. 22 is a cross-sectional view of the resistor 1 in this embodiment.

[0059] (Resistor 1) This embodiment has the same basic configuration as the fifth embodiment, but the shape of the plate terminals 25 is modified. In this embodiment, each of the pair of plate terminals 25 is bent in the thickness direction within the molded resin 3. In this embodiment, the pair of plate terminals 25 has a shape symmetrical with respect to the element longitudinal direction X. Each end of the pair of plate terminals 25 protrudes from the molded resin 3 to the outside of the molded resin 3. Hereinafter, the direction perpendicular to the element longitudinal direction X and in which the plate terminals 25 protrude from the molded resin 3 will be referred to as the vertical direction Z, and the direction perpendicular to the vertical direction Z and the element longitudinal direction X will be referred to as the horizontal direction Y. In addition, the side in which the plate terminals 25 protrude from the molded resin 3 will be referred to as the lower side, and the opposite side will be referred to as the upper side. Note that the terms "upper" and "lower" are used for convenience and do not limit the orientation of the resistor 1 relative to the vertical direction, for example, when the resistor 1 is in use.

[0060] The plate terminal 25 includes a first plate portion 251, a second plate portion 252, and a third plate portion 253. The first plate portion 251 is connected to the cap electrode 22 and is formed in a plate shape perpendicular to the longitudinal direction X of the element.

[0061] The second plate portion 252 extends from the lower end of the first plate portion 251 toward the center of the resistor element 21 in the element longitudinal direction X, and is formed in a plate shape perpendicular to the up-down direction Z. The second plate portion 252 constitutes an opposing portion that faces the resistor element 21 via the mold resin 3. When viewed from above, the width of the second plate portion 252 in the lateral direction Y is greater than the width of the resistor element 21 in the lateral direction Y.

[0062] The third plate portion 253 extends from the end of the second plate portion 252 on the side farther from the first plate portion 251. The width of the third plate portion 253 in the horizontal direction Y is smaller than the width of the second plate portion 252 in the horizontal direction Y, and the third plate portion 253 extends from approximately the center of the second plate portion 252 in the horizontal direction Y. The third plate portion 253 is formed so as to be bent downward from the second plate portion 252.

[0063] The entire first plate portion 251, the entire second plate portion 252, and the upper end of the third plate portion 253 of the plate terminals 25 are disposed within the molded resin 3, and most of the third plate portion 253 is exposed from the molded resin 3. The resistor 1 is electrically connected to a circuit board or the like at the third plate portions 253 of the pair of plate terminals 25 exposed from the molded resin 3. The rest is the same as in the fifth embodiment.

[0064] (Method for manufacturing resistor 1) Next, an example of a method for manufacturing the resistor 1 of this embodiment will be described with reference to FIG. First, the resistor body 2 is manufactured. Next, the resistor body 2 is set in a mold 4 for molding the molded resin 3. The mold 4 has an upper mold 41 and a lower mold 42 that can be aligned in the vertical direction Z. The lower mold 42 is located below the resistor body 2 and has insertion holes 421 for inserting the third plate portions 253. The resistor body 2 is positioned relative to the clamped upper mold 41 and lower mold 42 by inserting the third plate portions 253 of the pair of plate terminals 25 into the pair of insertion holes 421.

[0065] Then, a molten raw material that will become the molding resin 3 is injected into the cavity 40 in the mold 4 in which the resistor body 2 is disposed, and is hardened, thereby forming the molding resin 3.

[0066] (Functions and Effects of the Sixth Embodiment) In this embodiment, at least one of the pair of plate-like terminals 25 is bent in the thickness direction within the molded resin 3. This improves the heat dissipation of the entire resistor 1. This will be explained below.

[0067] Since plate terminal 25 is a portion of resistor 1 that is likely to have a relatively high thermal conductivity, heat is efficiently dissipated from plate terminal 25 to a circuit board or the like connected to plate terminal 25. Therefore, by bending plate terminal 25 in the thickness direction within molded resin 3, plate terminal 25 can more easily absorb the heat diffused from resistive element 21 to molded resin 3, thereby improving the efficiency of heat dissipation via plate terminal 25. As a result, according to this embodiment, the heat dissipation of resistor 1 as a whole can be improved.

[0068] Furthermore, at least one of the pair of plate terminals 25 has an opposing portion (second plate portion 252 in this embodiment) inside molded resin 3 that faces resistive element 21 via a part of molded resin 3. This increases the efficiency of heat transfer from resistive element 21 to the opposing portion via molded resin 3, making it easier to guide heat from resistive element 21 to plate terminal 25. This improves heat dissipation from plate terminal 25 to a circuit board or the like to which plate terminal 25 is connected, thereby improving the heat dissipation of resistor 1 as a whole. In addition, the same functions and effects as those of the fifth embodiment are provided.

[0069] In this embodiment, the second plate portion 252 is formed so as to extend from the first plate portion 251 toward the center of the resistor element 21 in the element longitudinal direction X, but this is not limiting. For example, the second plate portion 252 may be formed so as to extend from the first plate portion 251 toward a side away from the center of the resistor element 21 in the element longitudinal direction X.

[0070] (Summary of the embodiment) Next, the technical ideas grasped from the above-described embodiments will be described by using the reference numerals and the like in the embodiments. However, the reference numerals and the like in the following description do not limit the components in the claims to the members and the like specifically shown in the embodiments.

[0071] [1] A resistor (1) comprising a resistor body (2) and a molded resin (3) in which the resistor body (2) is embedded, the molded resin (3) containing a filler (32) having a higher thermal conductivity than a base resin (31).

[0072] [2] The resistor (1) according to [1], wherein the thermal conductivity of the molding resin (3) is 3 W / (m·K) or more and 10 W / (m·K) or less.

[0073] [3] The resistor body (2) has a resistive element (21), a pair of lead wires (23) electrically connected to the resistive element (21), and a pair of cylindrical sleeve members (24) through which the pair of lead wires (23) are respectively inserted, and at least a portion of each of the pair of sleeve members (24) is exposed from the molded resin (3). [1] The resistor (1) described in [2] or [3].

[0074] [4] The resistor (1) according to [1] or [2], wherein the resistor body (2) has a resistive element (21) and a pair of cap electrodes (22) fitted to both ends of the resistive element (21), and at least a portion of each of the pair of cap electrodes (22) is exposed from the molded resin (3).

[0075] [5] The resistor (1) according to [4], wherein a portion of each of the pair of cap electrodes (22) is exposed from the molding resin (3) and another portion of each is embedded within the molding resin (3).

[0076] [6] The resistor (1) according to [1] or [2], wherein the resistor body (2) further comprises a resistive element (21) and a pair of plate-shaped terminals (25) electrically connected to the resistive element (21), and at least a portion of each of the pair of plate-shaped terminals (25) is exposed from the molded resin (3).

[0077] [7] The resistor (1) according to [6], wherein at least one of the pair of plate-shaped terminals (25) is bent in the thickness direction within the molded resin (3).

[0078] [8] The resistor (1) according to [6] or [7], wherein at least one of the pair of plate-shaped terminals (25) has an opposing portion (252) inside the molded resin (3) that faces the resistive element (21) via a part of the molded resin (3).

[0079] [9] A method for manufacturing a resistor (1) according to any one of [1] to [8], comprising the steps of: manufacturing the resistor body (2); and placing the resistor body (2) in a mold (4), injecting molten raw materials constituting the molded resin (3) into the mold (4), and hardening the raw materials to form the molded resin (3).

[0080]

[10] A method for manufacturing the resistor (1) described in [3], comprising the steps of: manufacturing the resistor body (2); and placing the resistor body (2) in a mold (4) while holding the exposed portions of the pair of sleeve members (24) from the molded resin (3) with the mold (4); injecting molten raw materials constituting the molded resin (3) into the mold (4); and hardening the molten raw materials to form the molded resin (3).

[0081]

[11] A method for manufacturing the resistor (1) according to [4] or [5], comprising the steps of: manufacturing the resistor body (2); and placing the resistor body (2) in a mold (4) while holding the exposed portions of the pair of cap electrodes (22) from the molded resin (3) with the mold (4); injecting molten raw materials constituting the molded resin (3) into the mold (4); and hardening the molten raw materials to form the molded resin (3).

[0082]

[12] A method for manufacturing a resistor (1) according to any one of [6] to [8], comprising the steps of: manufacturing the resistor body (2); and placing the resistor body (2) in a mold (4) while holding the exposed portions of the pair of plate terminals (25) from the molded resin (3) with the mold (4); injecting molten raw materials constituting the molded resin (3) into the mold (4); and hardening the raw materials to form the molded resin (3).

[0083] (Addendum) Although the embodiments of the present invention have been described above, the invention according to the claims is not limited to the above-described embodiments. It should be noted that not all of the combinations of features described in the embodiments are necessarily essential to the means for solving the problems of the invention. Furthermore, the present invention can be appropriately modified and implemented within the scope of its spirit. [Explanation of symbols]

[0084] 1...Resistor 2...Resistor body 21...Resistance element 22...Cap electrode 23...Lead wire 24...Sleeve member 25...Plate terminal 252...Second plate portion (opposing portion) 3...Mold resin 31...Base resin 32...Filler 4...Mold

Claims

1. A resistor main body; a molding resin in which the resistor body is embedded, the molding resin contains a filler having a higher thermal conductivity than the base resin; the resistor body includes a resistor element, a pair of lead wires electrically connected to the resistor element, and a pair of cylindrical sleeve members through which the pair of lead wires are inserted, each of the pair of sleeve members has a rigidity greater than that of the lead wire; At least a portion of each of the pair of sleeve members is exposed from the molding resin. resistor.

2. A resistor main body; a molding resin in which the resistor body is embedded, the molding resin contains a filler having a higher thermal conductivity than the base resin; the resistor body has a resistor element and a pair of cap electrodes fitted to both ends of the resistor element, a pair of cap electrodes each having a portion exposed from the molding resin and another portion buried in the molding resin; resistor.

3. A resistor main body; a molding resin in which the resistor body is embedded, the molding resin contains a filler having a higher thermal conductivity than the base resin; the resistor body further includes a resistor element and a pair of plate-shaped terminals electrically connected to the resistor element; At least a portion of each of the pair of plate-like terminals is exposed from the molding resin, At least one of the pair of plate-like terminals is bent in the thickness direction within the molding resin, At least one of the pair of plate-like terminals has an opposing portion inside the molding resin that faces the resistor element via a part of the molding resin. resistor.

4. The resistor body further includes a pair of cap electrodes fitted to both ends of the resistor element, the opposing portion is opposed to a portion of the resistor element between the pair of cap electrodes; 4. The resistor of claim 3.

5. The thermal conductivity of the molding resin is 3 W / (m·K) or more and 10 W / (m·K) or less.

5. A resistor according to claim 1.

6. 10. A method for manufacturing the resistor of claim 1, comprising: manufacturing the resistor body; a step of placing the resistor body in a mold while holding portions of the pair of sleeve members exposed from the mold resin with the mold, and injecting molten raw material constituting the mold resin into the mold and hardening the raw material to form the mold resin, Resistor manufacturing method.

7. 3. A method for manufacturing a resistor according to claim 2, comprising the steps of: manufacturing the resistor body; a step of placing the resistor body in a mold while holding portions of the pair of cap electrodes exposed from the molding resin with the mold, and injecting molten raw material constituting the molding resin into the mold and hardening the raw material to form the molding resin, Resistor manufacturing method.

8. A method for manufacturing a resistor according to claim 3 or 4, comprising the steps of: manufacturing the resistor body; a step of placing the resistor body in a mold while holding portions of the pair of plate-like terminals exposed from the mold resin with the mold, and injecting molten raw material constituting the mold resin into the mold and hardening it to form the mold resin. Resistor manufacturing method.

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