Resistor

Abstract

To provide a resistor capable of scattering a stress applied to a case.SOLUTION: A resistor 1 comprises: a resistance body 21 that has a rectangular column-like main body part 211 in which a pair of side flat surfaces 211a and 211b facing back to back each other, and a pair of mounted parts 212 positioned in both ends of the main body part 211; a resistance element 2 that has a pair of mounting parts 22 mounted on the pair of mounted parts 212, and a pair of terminal boards 23 provided on the pair of mounting parts 22; and a case 3 that has a pair of side walls 31, an opening 32 formed on an upper end of the pair of side walls 31, a bottom wall 33 provided on a lower end of the side wall 31, and a housing space S formed by being surrounded by the pair of side walls 31 and the bottom wall 33, and housing the resistance body 21. The resistance body 21 is housed in the housing space S so that the pair of side flat surfaces 211a and 211b are opposite in parallel to inner side flat surfaces 311a and 311b of the pair of side walls 31.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a resistor. [Background technology]

[0002] Patent document 1 discloses a resistor comprising a cylindrical insulator, a pair of mounting terminals with terminal plates provided on both ends of the insulator, and a case having an opening on one side for housing the insulator with the terminal plate protruding outward from the opening. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 11-195503 Summary of the Invention [Problem to be solved by the invention]

[0004] In the resistor described in Patent Document 1, the housing space of the case housing the insulator is substantially rectangular in cross section, while the insulator is circular, so the shapes of the two are significantly different. When such a resistor is used for precharging electric vehicles, hybrid vehicles, etc., when the resistor instantaneously generates heat, stress tends to concentrate on the side wall of the case due to linear expansion of the resistance wire and insulator, and there is a risk of cracking the case, etc.

[0005] The present invention has been made in consideration of this problem, and has an object to provide a resistor capable of dispersing the stress applied to the case. [Means for solving the problem]

[0006] According to one aspect of the present invention, there is provided a resistor comprising: a resistor having a rectangular pillar-shaped main body portion having a pair of side surfaces facing each other and a pair of mounted portions located at both ends of the main body portion; a resistance element having a pair of mounting portions each mounted to a pair of the mounted portions and a pair of terminal plates provided on the mounted portions through the pair of mounting portions; and a box-shaped case having a pair of side walls extending along the height direction in a cross-sectional view, an opening formed at one end of the pair of side walls, a bottom wall provided at the other end of the pair of side walls so as to extend along the width direction in a cross-sectional view, and an accommodating space formed by being surrounded by the pair of side walls and the bottom wall and accommodating the resistor, wherein the resistor is accommodated in the accommodating space via a sealing material so that the pair of side surfaces each face the inner surfaces of the pair of side walls. Effect of the Invention

[0007] According to the aspects of the present invention, the stress applied to the case can be dispersed. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is an exploded view of the resistor according to the present embodiment. [Diagram 2] FIG. 2 is a perspective view of the resistor according to this embodiment, with the sealing material omitted. [Diagram 3] FIG. 3 is a schematic cross-sectional view taken along line III-III in FIG. 2, with the terminal portion and the resistance wires omitted. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. [Diagram 5] FIG. 5 is a front view of the resistance element with the terminal portion and the resistance wire omitted. [Figure 6] FIG. 6 is a front view of the resistance element with the resistance wire omitted. [Figure 7] FIG. 7 is a schematic cross-sectional view of a resistor according to a first modified example, with the terminal portion and the resistance wire omitted. [Figure 8]FIG. 8 is a schematic cross-sectional view of a resistor according to a second modified example, with the terminal portion and the resistance wire omitted. [Figure 9] FIG. 9 is a perspective view of a resistance element according to a third modified example. [Figure 10] FIG. 10 is a partial perspective view of a resistance element according to a fourth modification. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, a mode for carrying out the present invention (hereinafter, also simply referred to as an embodiment) will be described with reference to the attached drawings. In this specification, the same elements are given the same reference numerals throughout. In the drawings, the longitudinal direction, width direction, and height direction of the resistor 1 (case 3) are respectively defined as the direction along the X-axis, the direction along the Y-axis, and the direction along the Z-axis. Hereinafter, for convenience of explanation, the longitudinal direction, width direction, and height direction of the resistor 1 will be simply referred to as the longitudinal direction, width direction, and height direction.

[0010] First, the configuration of a resistor 1 according to this embodiment will be described with reference to FIGS.

[0011] FIG. 1 is an exploded view of the resistor 1 according to the present embodiment. FIG. 2 is a perspective view of the resistor 1 according to the present embodiment, with the cement material 4 omitted. FIG. 3 is a schematic cross-sectional view taken along line III-III in FIG. 2, with the terminal portion and the resistance wire 24 omitted and showing only the main portion. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 1. FIG. 5 is a front view of the resistance element 2 with the terminal portion and the resistance wire 24 omitted. FIG. 6 is a front view of the resistance element 2 with the resistance wire 24 omitted.

[0012] 1 to 6, the resistor 1 includes a resistive element 2, a box-shaped case 3 that houses a part of the resistive element 2 (i.e., a resistor 21, etc., which will be described later), and a cement material 4 (see FIG. 3) that serves as a sealant that seals the case 3 with the part of the resistive element 2 housed in the case 3. In this embodiment, the resistor 1 is used for precharging electric vehicles, hybrid vehicles, etc.

[0013] 1, the resistance element 2 includes a resistor 21, a pair of mounting portions 22, a pair of terminal plates 23, and a resistance wire 24. The pair of terminal portions are each formed of the pair of mounting portions 22 and the pair of terminal plates 23.

[0014] In this embodiment, the resistance element 2 has a resistor 21, a pair of mounting parts 22, a pair of terminal plates 23, and a resistance wire 24, but is not limited thereto, and may have, for example, a resistance film applied to the outer circumferential surface of the resistor 21 instead of the resistance wire 24. In this case, the resistance film is made of a metal film, a carbon film, a metal glaze film, a metal oxide film, or the like.

[0015] The resistor 21 is an insulator, and is made of an insulating material such as ceramics or a glass fiber bundle. As shown in Fig. 4, the resistor 21 has a prismatic (specifically, rectangular prismatic / more specifically, square prismatic) main body 211 and a pair of mounted portions 212 to which a pair of mounting portions 22 of a pair of terminal portions are respectively fitted.

[0016] 3, the main body 211 has a pair of side planes 211a and 211b as side surfaces facing each other, a top plane 211c as a top surface facing each other so as to be perpendicular to the pair of side planes 211a and 211b, and a bottom plane 211d as a bottom surface. From the viewpoint of making it easy to wind the resistance wire 24 around the outer periphery of the main body 211, it is preferable that R surfaces be formed at the four corners of the main body 211.

[0017] 1 and 4, the pair of mounted parts 212 are integrally formed with the main body part 211 so as to be located at both ends of the main body part 211. In this embodiment, the pair of mounted parts 212 are configured in a cylindrical shape. In contrast, if the pair of mounted parts are configured in a rectangular column shape, even the slightest twisting of the pair of mounted parts will result in the pair of terminal parts being bent and inserted in accordance with the twist of the pair of mounted parts. For this reason, with the mounted parts 212 according to this embodiment, it is easier to achieve positional accuracy for the terminal parts compared to a mounted part configured in a rectangular column shape.

[0018] 4 and 5, a step is formed between main body portion 211 and mounted portion 212, which is formed by end surface 211e of main body portion 211 exposed from mounted portion 212. As shown in Fig. 5, mounted portion 212 is provided such that the axis of mounted portion 212 and the axis of main body portion 211 coincide with each other in a front view, and is disposed within main body portion 211.

[0019] Furthermore, from the viewpoint of minimizing the stress difference on case 3 that occurs due to the difference in shape between main body portion 211 and mounted portion 212, it is preferable that the ratio of the cross-sectional area of ​​mounted portion 212 to the cross-sectional area of ​​main body portion 211 be 0.8 or more.

[0020] 1, 4 and 6, the pair of mounting parts 22 of the pair of terminal parts are respectively mounted on the pair of mounted parts 212. In this embodiment, the pair of mounting parts 22 are a pair of metallic cap terminals formed in a cylindrical shape with a bottom. The pair of mounting parts 22 are made of, for example, iron or copper.

[0021] Each mounting portion 22 has a peripheral wall 221 formed to a uniform thickness d. The thickness d of the peripheral wall 221 is formed to be larger than the minimum height h of the step (i.e., the minimum distance between the outer circumferential surface of the mounted portion 212 and the outer circumferential surface of the main body portion 211 / see FIG. 4). Specifically, the minimum height h of the step is 1 / 3 or more of the thickness d of the peripheral wall 221 and smaller than the thickness d of the peripheral wall 221. As a result, as shown in FIG. 6, in a state in which each mounting portion 22 is mounted on each mounted portion 212, each mounting portion 22 has a weldable region 222 that protrudes outward from one side flat surface 211a of the main body portion 211. Note that in this embodiment, the weldable region 222 protrudes outward from one side flat surface 211a of the main body portion 211, but is not limited thereto. For example, the weldable region 222 may protrude outward from the other side flat surface 211b of the main body portion 211, top plane It may protrude outward from 211c or bottom plane 211d.

[0022] 1 and 4, the pair of terminal plates 23 are provided on the mounted portion 212 through the pair of mounting portions 22. The pair of terminal plates 23 are made of a metal plate having electrical conductivity. Specifically, the pair of terminal plates 23 are made of, for example, iron or copper. In the present embodiment, the pair of terminal plates 23 are integrally formed with the pair of mounting portions 22, but the present invention is not limited thereto, and the pair of terminal plates 23 may be joined to the pair of mounting portions 22 by welding, for example. The pair of terminal plates 23 may be provided with protrusions for positioning parts of the pair of terminal plates 23 in the accommodation space S of the case 3.

[0023] The resistance wire 24 is made of a conductive metal wire material. Specifically, the resistance wire 24 is made of, for example, a nickel-iron alloy (Ni-Fe), a copper-nickel alloy (Cu-Ni), nickel (Ni), chromium (Cr), a nickel-chromium alloy (Ni-Cr), or the like.

[0024] 1 and 4, the resistance wire 24 is wound around the outer circumferential surface of the main body 211 so that the end 241 is fixed to the weldable region 222 by welding. As described above, the weldable region 222 protrudes outward from one side surface 211a of the main body 211. Therefore, when the resistance wire 24 is wound from the weldable region 222 (i.e., a high position / outer position) to the outer circumferential surface of the main body 211 (i.e., a low position / inner position), the load in the peeling direction (see arrow R in FIG. 1 / specifically, a radial direction perpendicular to the weldable region 222) on the welding point where the end 241 and the weldable region 222 are welded can be reduced.

[0025] As described above, since the thickness d of the peripheral wall 221 is formed to be larger than the minimum height h of the step, the dimensions of the resistor 21 in the width direction and height direction after winding are less affected by the diameter of the resistance wire 24, compared to when the thickness d of the peripheral wall 221 is equal to or smaller than the minimum height h of the step. This is because, if the minimum height h of the step is larger than the thickness d of the peripheral wall 221, the only way to change the resistance value without changing the dimensions of the main body 211 is to change the diameter of the resistance wire 24, and the outermost diameter of the resistor 21 is affected by the difference in the diameter of the resistance wire 24, which changes the dimensions of the entire resistor 21 in the width direction and height direction, resulting in contact with the case 3 or other design defects.

[0026] 1 and 3, the case 3 is a top-open box type case made of ceramics etc. In this embodiment, the case 3 is made of ceramics etc., but is not limited thereto and may be made of, for example, a resin material, alumina or a metal material.

[0027] The case 3 has a pair of side walls 31 extending along the height direction in a cross-sectional view and facing both side surfaces of the terminal board 23, an opening 32 formed at an upper end as one end of the pair of side walls 31, a bottom wall 33 formed at a lower end as the other end of the pair of side walls 31 so as to extend along the width direction in a cross-sectional view, a pair of end walls 34 connecting the pair of side walls 31, and a storage space S formed by being surrounded by the pair of side walls 31, the bottom wall 33 and the pair of end walls 34 and for accommodating the resistor 21.

[0028] The pair of side walls 31 have inner flat surfaces 311a, 311b as a pair of inner surfaces parallel to each other. When the resistor 21 is accommodated in the accommodation space S of the case 3 via the cement material 4, the pair of side flat surfaces 211a, 211b of the main body 211 face the pair of inner flat surfaces 311a, 311b in parallel. This makes it possible to make the distance between one side flat surface 211a and one inner flat surface 311a (or the distance between the other side flat surface 211b and the other inner flat surface 311b) uniform, so that the stress applied from the main body 211 to each side wall 31 of the case 3 can be dispersed more effectively than when a cylindrical main body is accommodated in the case 3. In addition, it is possible to suppress twisting of the terminal portion in the left-right and front-back directions.

[0029] In this embodiment, the pair of inner surfaces are composed of inner planes 311a, 311b that are parallel to each other, but are not limited to this and may be composed of, for example, a pair of inclined surfaces or a pair of curved surfaces that are formed so that the distance between them becomes smaller from the upper end side of the side wall 31 to the lower end side of the side wall 31.

[0030] From the viewpoint of uniformly distributing the stress applied from the main body 211 to each side wall 31 of the case 3, the first proportion, which is the ratio of the first distance p1 (see FIG. 3; hereinafter also simply referred to as the first distance p1) which is the distance between the one side plane 211a and the inner plane 311a of the one side wall 31a, to the second distance p2 (see FIG. 3; hereinafter also simply referred to as the second distance p2) which is the distance between the other side plane 211b and the inner plane 311b of the other side wall 31b, is preferably between 0.8 and 1.2, and more preferably between 0.9 and 1.1. Furthermore, it is most preferable that the first proportion is 1.0, that is, the first distance p1 and the second distance p2 are equal.

[0031] When the first proportion is less than 0.8, the one side plane 211a and the one inner plane 311a are too close to each other, so that the stress applied from the main body 211 to the one side wall 31a is more concentrated than that to the other side wall 31b, increasing the risk of cracking the one side wall 31a. On the other hand, when the first proportion is more than 1.2, the other side plane 211b and the other inner plane 311b are too close to each other, so that the stress applied from the main body 211 to the other side wall 31b is more concentrated than that to the one side wall 31a, increasing the risk of cracking the other side wall 31b.

[0032] In addition, the pair of side walls 31 are configured to have a substantially uniform thickness. This makes it possible to make uniform the distance from one side plane 211a to the outer plane 312a of one side wall 31a (or the distance from the other side plane 211b to the outer plane 312b of the other side wall 31b), so that when the resistor 1 instantaneously generates heat, heat dissipation (heat escape, heat dispersion) from the main body 211 of the resistor 21 to the outside of the side wall 31 of the case 3 can be stabilized.

[0033] Opening 32 is an open portion of case 3, and corresponds to a boundary between the outside and accommodating space S of case 3. Lower ends as base ends of a pair of terminal boards 23 are accommodated in accommodating space S through opening 32.

[0034] The bottom wall 33 has an inner flat surface 331 perpendicular to the inner flat surfaces 311a, 311b of the pair of side walls 31. When the resistor 21 is accommodated in the accommodation space S of the case 3 via the cement material 4, the bottom flat surface 211d of the main body 211 faces parallel to the inner flat surface 331 of the bottom wall 33. This allows the distance between the bottom flat surface 211d of the main body 211 and the inner flat surface 331 of the bottom wall 33 to be made uniform (described later), so that the stress applied from the main body 211 to the bottom wall 33 of the case 3 can be dispersed more effectively than when a cylindrical main body is accommodated in the case 3.

[0035] From the viewpoint of evenly dispersing the stress applied from the main body 211 to each wall 31, 33 of the case 3, the second ratio, which is the ratio of the first distance p1 (see FIG. 3) which is the distance between one side plane 211a and the inner plane 311a of one side wall 31a, to the third distance p3 (see FIG. 3 / hereinafter also simply referred to as the third distance p3) which is the distance between the bottom plane 211d of the main body 211 and the inner plane 331 of the bottom wall 33, is preferably between 0.8 and 1.2, and more preferably between 0.9 and 1.1. Furthermore, it is most preferable that the second ratio is 1.0, that is, the first distance p1 and the third distance p3 are equal.

[0036] When the second ratio is less than 0.8, the side plane 211a and the inner plane 311a are too close to each other, so that the stress applied from the main body 211 to the side wall 31a is more concentrated than that to the bottom wall 33, increasing the risk of cracking the side wall 31a. On the other hand, when the second ratio is more than 1.2, the bottom plane 211d of the main body 211 and the inner plane 331 of the bottom wall 33 are too close to each other, so that the stress applied from the main body 211 to the bottom wall 33 is more concentrated than that to the side wall 31a, increasing the risk of cracking the bottom wall 33.

[0037] From the viewpoint of evenly dispersing the stress applied from the main body 211 to each wall 31, 33 of the case 3, the third proportion, which is the ratio of the second distance p2 (see FIG. 3) which is the distance between the other side plane 211b and the inner plane 311b of the other side wall 31b, to the third distance p3 (see FIG. 3) which is the distance between the bottom plane 211d of the main body 211 and the inner plane 331 of the bottom wall 33, is preferably between 0.9 and 1.1, and more preferably between 0.95 and 1.05. Furthermore, it is most preferable that the third proportion is 1.0, that is, the second distance p2 and the third distance p3 are equal.

[0038] When the third ratio is less than 0.9, the other side plane 211b and the other inner plane 311b are too close to each other, so that the stress applied from the main body 211 to the other side wall 31b is concentrated more than that to the bottom wall 33, increasing the risk of cracking the other side wall 31b. On the other hand, when the third ratio is more than 1.1, the bottom plane 211d of the main body 211 and the inner plane 331 of the bottom wall 33 are too close to each other, so that the stress applied from the main body 211 to the bottom wall 33 is concentrated more than that to the other side wall 31b, increasing the risk of cracking the bottom wall 33.

[0039] In addition, the bottom wall 33 is configured to have a uniform thickness. This allows the distance from the bottom plane 211d of the main body 211 to the outer plane 332 of the bottom wall 33 to be uniform, so that when the resistor 1 generates heat instantaneously, heat dissipation from the main body 211 of the resistive element 21 to the outside of the bottom wall 33 of the case 3 can be stabilized. Note that it is preferable that the thickness of the bottom wall 33 is the same as the thickness of the side wall 31. This allows heat dissipation from the main body 211 of the resistive element 21 to the outside of the case 3 can be stabilized when the resistor 1 generates heat instantaneously.

[0040] As described above, the resistor 21 is accommodated in the accommodation space S of the case 3 via the cement material 4 such that the pair of side planes 211a, 211b and the bottom plane 211d of the main body 211 face in parallel with the pair of inner planes 311a, 311b and the inner plane 331 of the bottom wall 33, respectively. This allows the accommodation space S of the case 3 to be used more efficiently than when a cylindrical main body is accommodated in the case 3, and therefore allows the capacity (volume) of the resistance wire 24 to be sufficiently secured. As a result, the pulse resistance characteristics of electric vehicles, hybrid vehicles, etc. are improved.

[0041] Furthermore, compared to a case in which a cylindrical main body is housed in a case 3, the amount of cement material 4 filled between the outside of the main body 211 and the inside of the case 3 can be reduced, thereby preventing cracks from occurring in the case 3 due to thermal expansion of the cement material 4.

[0042] The pair of end walls 34 face the pair of mounting portions 22, respectively. A clearance is formed between each end wall 34 and each mounting portion 22. This makes it possible to prevent damage to each mounting portion 22 due to contact between each end wall 34 and each mounting portion 22.

[0043] In order to maximize the storage space S without increasing the external size of the case 3 while maintaining the strength of the case 3, each corner of the storage space S is rounded as shown in Fig. 3. This makes it possible to maintain the strength of the case 3, and therefore reduces the effects of thermal expansion, making it less likely for cracks to occur in the corners of the storage space S.

[0044] (Modification) Next, a resistor 1 according to a modification will be described with reference to Fig. 7 to Fig. 10. Note that in the modification, points that are the same as those in the above-mentioned embodiment will be omitted, and points that are different from the above-mentioned embodiment will be mainly described.

[0045] Fig. 7 is a schematic cross-sectional view of a resistor 1 according to a first modified example, showing only the essential parts with the terminals and resistance wire 24 omitted. Fig. 8 is a schematic cross-sectional view of a resistor 1 according to a second modified example, showing only the essential parts with the terminals and resistance wire 24 omitted. Fig. 9 is a perspective view of a resistance element 2 according to a third modified example. Fig. 10 is a partial perspective view of a resistance element 2 according to a fourth modified example.

[0046] In the above-described embodiment, the pair of side surfaces are each composed of a pair of side planes 211a, 211b, but the present invention is not limited thereto, and may be composed of a first curved surface 211A and a second curved surface 211B as a pair of curved surfaces that protrude toward the inner surfaces of the pair of side walls 31 in a cross-sectional view, as shown in Fig. 7. The first curved surface 211A and the second curved surface 211B have the same curvature.

[0047] 7, R-surfaces C are formed at the four corners of the square columnar main body 211. Specifically, a first R-surface C1, a second R-surface C2, a third R-surface C3, and a fourth R-surface C4 are formed at the upper right corner of the main body 211, the lower right corner of the main body 211, the upper left corner of the main body 211, and the lower left corner of the main body 211, respectively. The first R-surface C1, the second R-surface C2, the third R-surface C3, and the fourth R-surface C4 have the same curvature.

[0048] The first curved surface 211A as one of the curved surfaces is formed to be located between the first R-surface C1 and the second R-surface C2. Specifically, the first curved surface 211A is formed so that an upper end as one end is connected to a lower end of the first R-surface C1 and a lower end as the other end is connected to an upper end of the second R-surface C2 in a cross-sectional view. In addition, the first curved surface 211A is formed so that the curvature is different from the curvatures of the first R-surface C1 and the second R-surface C2 in a cross-sectional view.

[0049] An upper end of the first curved surface 211A is located closer to the opening 32 than to the bottom wall 33, i.e., it is spaced apart from the bottom wall 33. A lower end of the first curved surface 211A is located closer to the bottom wall 33 than to the opening 32, i.e., it is spaced apart from the opening 32. One imaginary straight line L1 connecting the upper and lower ends (i.e., both ends) of the first curved surface 211A is formed to extend along the height direction.

[0050] Similarly, the second curved surface 211B as the other curved surface is formed to be located between the third R surface C3 and the fourth R surface C4. Specifically, the second curved surface 211B is formed so that its upper end is connected to the lower end of the third R surface C3 and its lower end is connected to the upper end of the fourth R surface C4 in a horizontal cross-sectional view. In addition, the second curved surface 211B is formed so that its curvature is different from that of the third R surface C3 and the fourth R surface C4 in a horizontal cross-sectional view.

[0051] An upper end of the second curved surface 211B is located closer to the opening 32 than to the bottom wall 33, i.e., separated from the bottom wall 33. Also, a lower end of the second curved surface 211B is located closer to the bottom wall 33 than to the opening 32, i.e., separated from the opening 32. The other imaginary straight line L2 connecting the upper and lower ends (i.e., both ends) of the second curved surface 211B is formed to extend along the height direction.

[0052] In addition, from the viewpoint of evenly dispersing the heat and stress applied from the main body portion 211 to one side wall 31a of the case 3 and making it easy to wind the resistance wire 24 in a state of close contact with the outer peripheral surface of the main body portion 211, the ratio of the maximum first distance p1max (see FIG. 7 / hereinafter also referred to simply as the maximum first distance p1max), which is the distance between the upper end of the first curved surface 211A and the inner flat surface 311a of one side wall 31a, to the minimum first distance p1min (see FIG. 7 / hereinafter also referred to simply as the minimum first distance p1min), which is the distance between the apex of the first curved surface 211A and the inner flat surface 311a of one side wall 31a, is preferably greater than 1.0 and not greater than 2.5, and more preferably falls between 1.3 and 2.0.

[0053] When the ratio between the maximum first distance p1max and the minimum first distance p1min is 1.0, the side surface becomes a flat side surface instead of the first curved surface 211A, making it difficult to bring the resistance wire 24 into close contact with the outer circumferential surface of the main body portion 211. On the other hand, when the ratio between the maximum first distance p1max and the minimum first distance p1min exceeds 2.5, it becomes difficult to evenly distribute the heat and stress applied from the main body portion 211 to one side wall 31a.

[0054] Similarly, from the viewpoint of evenly dispersing the heat and stress applied from the main body portion 211 to the other side wall 31b of the case 3 and making it easy to wind the resistance wire 24 in a state of close contact with the outer peripheral surface of the main body portion 211, the ratio of the maximum second distance p2max (see Figure 7 / hereinafter also simply referred to as the maximum second distance p2max), which is the distance between the upper end of the second curved surface 211B and the inner flat surface 311b of the other side wall 31b, to the minimum second distance p2min (see Figure 7 / hereinafter also simply referred to as the minimum second distance p2min), which is the distance between the apex of the second curved surface 211B and the inner flat surface 311b of the other side wall 31b, is preferably greater than 1.0 and not greater than 2.5, and more preferably falls between 1.3 and 2.0.

[0055] When the ratio between the maximum second distance p2max and the minimum second distance p2min is 1.0, the side surface becomes a flat side surface instead of the second curved surface 211B, making it difficult to bring the resistance wire 24 into close contact with the outer circumferential surface of the main body portion 211. On the other hand, when the ratio between the maximum second distance p2max and the minimum second distance p2min exceeds 2.5, it becomes difficult to evenly distribute the heat and stress applied from the main body portion 211 to the other side wall 31b.

[0056] From the viewpoint of evenly dispersing the heat and stress applied from the main body 211 to each side wall 31 of the case 3, the maximum first proportion, which is the ratio between the maximum first distance p1max and the maximum second distance p2max, is preferably between 0.8 and 1.2, and more preferably between 0.9 and 1.1. Moreover, the maximum first proportion is most preferably 1.0, that is, the maximum first distance p1max and the maximum second distance p2max are equal to each other.

[0057] Furthermore, from the viewpoint of evenly dispersing the heat and stress applied from the main body 211 to each side wall 31 of the case 3, the minimum first proportion, which is the ratio between the minimum first distance p1min and the minimum second distance p2min, is preferably between 0.8 and 1.2, and more preferably between 0.9 and 1.1. Furthermore, the minimum first proportion is most preferably 1.0, that is, the minimum first distance p1min and the minimum second distance p2min are equal to each other.

[0058] In the first modified example, the top surface and the bottom surface are respectively constituted by a third curved surface 211C protruding toward the opening 32 side and a fourth curved surface 211D protruding toward the bottom wall 33 side. This makes it easier to wind the resistance wire 24 around the outer circumferential surface of the main body 211. The first curved surface 211A, the second curved surface 211B, the third curved surface 211C, and the fourth curved surface 211D have the same curvature.

[0059] The third curved surface 211C is formed so as to be located between the first R-surface C1 and the third R-surface C3. Specifically, the third curved surface 211C is formed so that the right end thereof is connected to the left end of the first R-surface C1 and the left end thereof is connected to the right end of the third R-surface C3 in cross-sectional view. In addition, the third curved surface 211C is formed so as to have a curvature different from the curvatures of the first R-surface C1 and the third R-surface C3 in cross-sectional view.

[0060] The fourth curved surface 211D is formed so as to be located between the second R-surface C2 and the fourth R-surface C4. Specifically, the fourth curved surface 211D is formed so that the right end thereof is connected to the left end of the second R-surface C2 and the left end thereof is connected to the right end of the fourth R-surface C4 in a cross-sectional view. In addition, the fourth curved surface 211D is formed so as to have a curvature different from the curvatures of the second R-surface C2 and the fourth R-surface C4 in a cross-sectional view.

[0061] Similarly, from the viewpoint of evenly dispersing the heat and stress applied from the main body portion 211 to the bottom wall 33 of the case 3 and making it easy to wind the resistance wire 24 in a state of close contact with the outer peripheral surface of the main body portion 211, the ratio of the maximum third distance p3max (see Figure 7 / hereinafter also referred to simply as the maximum third distance p3max), which is the distance between the end of the fourth curved surface 211D and the inner flat surface 331 of the bottom wall 33, to the minimum third distance p3min (see Figure 7 / hereinafter also referred to simply as the minimum third distance p3min), which is the distance between the apex of the fourth curved surface 211D and the inner flat surface 331 of the bottom wall 33, is preferably greater than 1.0 and not greater than 2.5, and more preferably between 1.3 and 2.0.

[0062] When the ratio between the maximum third distance p3max and the minimum third distance p3min is 1.0, the side surface becomes a flat side surface instead of the fourth curved surface 211D, making it difficult to wind the resistance wire 24 in close contact with the outer circumferential surface of the main body portion 211. On the other hand, when the ratio between the maximum third distance p3max and the minimum third distance p3min exceeds 2.5, it becomes difficult to evenly disperse the heat and stress applied from the main body portion 211 to the bottom wall 33.

[0063] In the above-described embodiment, the main body 211 is configured to have a rectangular columnar shape in cross section, but is not limited thereto, and may be configured to have an octagonal columnar shape in cross section, for example, as shown in Fig. 8. In this case, it is easier to wind the resistance wire 24 around the main body 211 compared to when the main body 211 is configured to have a rectangular columnar shape.

[0064] In addition, in the above-described embodiment, the mounted portion 212 and the mounting portion 22 are configured in a cylindrical shape and a bottomed cylindrical shape, respectively, but are not limited to this. For example, as shown in FIG. 9, the mounted portion 212 and the mounting portion 22 may be configured in a prismatic shape (specifically, a rectangular prismatic shape) and a bottomed square tube shape (specifically, a bottomed rectangular tube shape), respectively.

[0065] In this case, since the main body 211 and the mounted part 212 constituting the resistor 21 are both configured in a prismatic shape, there is almost no difference in shape between the main body 211 and the mounted part 212, and the stress difference caused by this can be suppressed. Also, the mounted part 212 is provided so that each outer peripheral surface faces parallel to each inner peripheral surface of the case 3, similar to each outer peripheral surface of the main body 211. This makes it possible to disperse the stress applied to the case 3 from the mounted part 212, compared to when a cylindrical mounted part is housed in the case 3.

[0066] In addition, in the above-mentioned third modified example, the mounting portion 22 is configured as a cap terminal having a bottomed rectangular cylindrical shape, but this is not limited to this and may be configured as a clip terminal, for example, as shown in FIG. 10.

[0067] 10, the upper and lower surfaces of the mounted portion 212 are clamped by the clamping portion 223 of the mounting portion 22. The mounting portion 22 has a weldable region 222 that protrudes outward from one side flat surface 211a of the main body portion 211, as in the above-described embodiment.

[0068] In addition, in the above-described embodiment, the two mounting portions 22 are composed of two cap terminals, but this is not limited to this and may be composed of, for example, a combination of one cap terminal and one clip terminal.

[0069] (Action and effect) Next, the effects of the embodiment and the modified example will be described.

[0070] The resistor 1 according to the above-described embodiment includes a resistor 21 having a rectangular columnar main body 211 having a pair of side planes 211a, 211b facing each other, and a pair of mounting portions 212 located at both ends of the main body 211, a resistance element 2 having a pair of mounting portions 22 mounted on the pair of mounting portions 212, and a pair of terminal plates 23 provided on the mounting portion 212 via the pair of mounting portions 22, and a box-shaped case 3 having a pair of side walls 31, an opening 32 formed at the upper ends of the pair of side walls 31, a bottom wall 33 provided at the lower end of the side walls 31, and an accommodation space S formed by being surrounded by the pair of side walls 31 and the bottom wall 33 and accommodating the resistor 21, and the resistor 21 is accommodated in the accommodation space S via a cement material 4 so that the pair of side planes 211a, 211b face the inner planes 311a, 311b of the pair of side walls 31, respectively.

[0071] According to this configuration, the distance between one side plane 211a and one inner plane 311a (or the distance between the other side plane 211b and the other inner plane 311b) can be made uniform, so that the stress applied from the main body 211 to each side wall 31 of the case 3 can be dispersed, compared to a case in which a cylindrical main body is housed in the case 3. In addition, twisting of the terminal portion can be suppressed. Also, compared to a case in which a cylindrical main body is housed in the case 3, the distance between the heat-generating resistance element 2 and each side wall 31 of the case 3 can be made shorter overall, so that the generated heat can be dispersed and heat concentration can be suppressed.

[0072] In the first modified example described above, the pair of side surfaces are composed of a pair of first curved surfaces 211A and second curved surfaces 211B that protrude toward the inner surfaces of the pair of side walls 31, and a pair of imaginary straight lines L1 and L2 that connect both ends of the pair of first curved surfaces 211A and second curved surfaces 211B in a cross-sectional view extend along the height direction, and a maximum first distance p1max that is the distance between the upper end of the first curved surface 211A and the inner flat surface 311a of one of the side walls 31a and a first bay The ratio of the minimum first distance p1min, which is the distance between the vertex of the curved surface 211A and the inner plane 311a of one side wall 31a, to the maximum second distance p2max, which is the distance between the upper end of the second curved surface 211B and the inner plane 311b of the other side wall 31b, to the minimum second distance p2min, which is the distance between the vertex of the second curved surface 211B and the inner plane 311b of the other side wall 31b, is greater than 1.0 and less than 2.5.

[0073] According to this configuration, the heat and stress applied from the main body 211 to each side wall 31 of the case 3 can be evenly dispersed, and the resistance wire 24 can be easily wound in a state of tight contact with the outer circumferential surface of the main body 211.

[0074] Furthermore, in the first modified example described above, the maximum first proportion, which is the ratio between the maximum first distance p1max and the maximum second distance p2max, falls between 0.8 and 1.2, and the minimum first proportion, which is the ratio between the minimum first distance p1min and the minimum second distance p2min, falls between 0.8 and 1.2.

[0075] According to these configurations, the heat and stress applied from the main body 211 to each side wall 31 of the case 3 can be dispersed more evenly.

[0076] In the above-described embodiment and the first modified example, the main body 211 has four corners each having a rounded surface.

[0077] This configuration makes it easier to wind the resistance wire 24 around the outer circumferential surface of the main body portion 211.

[0078] In addition, in the above-described embodiment, the pair of side planes 211a, 211b face the pair of inner planes 311a, 311b in parallel, respectively, and the first proportion, which is the ratio of a first distance p1, which is the distance between one side plane 211a and the inner plane 311a of one side wall 31a, to a second distance p2, which is the distance between the other side plane 211b and the inner plane 311b of the other side wall 31b, falls within the range of 0.8 to 1.2.

[0079] According to this configuration, the stress applied from the main body 211 to each side wall 31 of the case 3 can be evenly distributed.

[0080] In addition, in the above-described embodiment, the resistor 21 is accommodated in the accommodation space S so that the bottom plane 211d of the main body portion 211 faces parallel to the inner plane 331 of the bottom wall 33, and the second proportion, which is the ratio of the first distance P1 to the third distance p3, which is the distance between the bottom plane 211d and the inner plane 331 of the bottom wall 33, falls between 0.8 and 1.2, and the third proportion, which is the ratio of the second distance p2 to the third distance p3, falls between 0.8 and 1.2.

[0081] According to this configuration, the distance between the bottom plane 211d of the main body 211 and the inner plane 331 of the bottom wall 33 can be made uniform, so that the stress applied from the main body 211 to the bottom wall 33 of the case 3 can be dispersed more effectively than in a case where a cylindrical main body is housed in the case 3. Also, the stress applied from the main body 211 to the walls 31, 33 of the case 3 can be dispersed evenly.

[0082] In addition, in the above-described embodiment, the mounting portion 22 has a weldable region 222 that protrudes outward from one side plane 211a of the main body portion 211 when mounted on the mounted portion 212, and the resistance element 2 further has a resistance wire 24 wound around the outer circumferential surface of the main body portion 211 so that the end portion 241 is fixed to the weldable region 222 by welding.

[0083] According to this configuration, by winding the resistance wire 24 from the weldable region 222 (i.e., a high position / outer position) to the outer peripheral surface of the main body portion 211 (i.e., a low position / inner position), the load in the direction of peeling off the welded point where the end portion 241 and the weldable region 222 are welded can be reduced.

[0084] In this modification, the mounting portion 212 is configured in a rectangular column shape similar to the main body portion 211 .

[0085] With this configuration, the stress applied to the case 3 from the mounted portion 212 can be dispersed more effectively than in a case where a cylindrical mounted portion is housed in the case 3 .

[0086] In the above-described embodiment, the mounted portion 212 fits within the main body portion 211 in cross-sectional view, and the ratio of the cross-sectional area of ​​the mounted portion 212 to the cross-sectional area of ​​the main body portion 211 is 0.8 or more.

[0087] According to this configuration, the difference in stress on case 3 caused by the difference in shape between main body portion 211 and mounted portion 212 can be kept small.

[0088] Although the present embodiment has been described above, the above embodiment merely illustrates some of the application examples of the present invention, and is not intended to limit the technical scope of the present invention to the specific configurations of the above embodiment. [Explanation of symbols]

[0089] 1 resistor 2. Resistance element 3 Cases 4 Cement materials (sealing materials) 21 Resistor 22 Mounting part 23 Terminal board 31 Side wall 32 Aperture 33 Bottom Wall 211 Main body 211a One side plane 211b Other side plane 212 Attached part 311 Medial plane S Storage space

Claims

1. A resistor having a prismatic body having a pair of side surfaces facing each other, and a pair of mounting parts located at both ends of the body; A pair of mounting parts respectively mounted on the pair of mounting parts; a resistor element including a pair of terminal plates provided on the mounted portion through a pair of the mounting portions; a box-shaped case having a pair of side walls extending along a height direction in a cross-sectional view, an opening formed at one end of the pair of side walls, a bottom wall provided at the other end of the pair of side walls so as to extend along a width direction in a cross-sectional view, and an accommodation space formed by being surrounded by the pair of side walls and the bottom wall and accommodating the resistor; the resistor is accommodated in the accommodation space via a sealing material such that the pair of side surfaces face the pair of inner surfaces of the side walls, respectively; resistor.

2. The prismatic shape is a square prismatic shape, The pair of side surfaces are each formed of a pair of curved surfaces protruding toward the inner surfaces of the pair of side walls, A pair of imaginary straight lines connecting both ends of the pair of curved surfaces in a cross-sectional view extend along a height direction, a ratio of a maximum first distance, which is a distance between one end of one of the curved surfaces located closer to the opening than the bottom wall side and one of the inner surfaces, to a minimum first distance, which is a distance between a vertex of one of the curved surfaces and one of the inner surfaces, is greater than 1.0 and is equal to or smaller than 2.5; a ratio of a maximum second distance, which is a distance between one end of the other curved surface located closer to the opening than the bottom wall side and the other inner surface, to a minimum second distance, which is a distance between a vertex of the other curved surface and the other inner surface, is greater than 1.0 and is equal to or less than 2.5; 2. The resistor of claim 1.

3. a maximum first proportion, which is a ratio between the maximum first distance and the maximum second distance, falls between 0.8 and 1.2; a minimum first proportion, which is a ratio between the minimum first distance and the minimum second distance, is between 0.8 and 1.2; 3. The resistor of claim 2.

4. The four corners of the main body are formed with R surfaces.

3. The resistor of claim 2.

5. The pair of side surfaces are parallel to and face the pair of inner side surfaces, A first proportionality, which is a ratio of a first distance, which is a distance between one of the side surfaces and an inner surface of one of the side walls, to a second distance, which is a distance between the other of the side surfaces and an inner surface of the other of the side walls, is between 0.8 and 1.2; 2. The resistor of claim 1.

6. The resistor is accommodated in the accommodation space such that a bottom surface of the main body faces an inner surface of the bottom wall in parallel therewith, a second proportionality, which is a ratio of the first distance to a third distance, which is a distance between the bottom plane and an inner plane of the bottom wall, is between 0.8 and 1.2; a third proportionality, which is a ratio between the second distance and the third distance, is between 0.8 and 1.2; 6. The resistor of claim 5.

7. The prismatic shape is a square prismatic shape, The four corners of the main body are formed with R surfaces.

6. The resistor of claim 5.

8. the mounting portion has a weldable region that protrudes outward from the side surface of the main body portion when the mounting portion is mounted on the mounted portion, The resistance element further includes a resistance wire wound around an outer circumferential surface of the body portion such that an end of the resistance wire is fixed to the weldable region by welding.

2. The resistor of claim 1.

9. a step is formed between the main body portion and the mounting portion, the step being formed by an end surface of the main body portion exposed from the mounting portion; The minimum height of the step is equal to or greater than 1 / 3 of the thickness of the peripheral wall of the mounting portion and is smaller than the thickness of the peripheral wall.

9. The resistor of claim 8.

10. The mounting portion is configured in a prismatic shape similar to that of the main body portion.

2. The resistor of claim 1.

11. The mounting portion is disposed within the main body portion in a cross-sectional view, The ratio of the cross-sectional area of ​​the mounting portion to the cross-sectional area of ​​the main body portion is 0.8 or more.

2. The resistor of claim 1.

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