JP5110571B2 - Cement resistor and manufacturing method thereof - Google Patents

Description

  The present invention relates to a cement resistor in which a resistor is sealed with cement in a case and a method for manufacturing the same.

  Conventionally, as an electronic component in consideration of safety, a cement resistor in which a resistor is sealed with an inorganic cement or the like in an insulating case such as a ceramic case is used.

As disclosed in Patent Document 1, as a resistor to be sealed, a resistance film is formed on a cylindrical insulator, caps are press-fitted on both ends, and a groove for correcting a resistance value is spirally formed. And using a resistance element in which lead wires are welded to both ends, and using a resistance wire and being supported by an insulating core plate in an insulating case as disclosed in Patent Document 2, are known. Yes. There is also a type using a resistor obtained by press cutting a metal plate.
Japanese Utility Model Publication No. 6-14401 JP 2002-231504 A

  The conventional cement resistor enclosing a resistance element and the cement resistor using a resistance wire have a problem that heat dissipation is not good because the resistor is surrounded by an insulating filler. Moreover, in the thing using a resistance wire, an insulating core board is required for support, and there exists a problem from a cost side. In a cement resistor using a resistor obtained by press-cutting a metal plate, there is a problem that distortion occurs on the cut surface of the resistor and a drift of the resistance value occurs.

  The present invention has been made in view of the above-described circumstances, and it is an object of the present invention to provide a cement resistor that can improve heat dissipation and does not require support of a resistor during assembly and a method for manufacturing the same. is there.

  The present invention provides a cement resistor in which a ribbon-like resistor having lead terminals attached to both ends is bent and stored in a U-shape in a storage space in an insulating case, and is filled with an insulating filler. And the inner wall where the outer surface of the ribbon-shaped resistor between the lead terminals in the storage space contacts is the same shape as the U-shape, and the ribbon-shaped resistor is the U-shape In the bent state, it has elasticity in the expanding direction and is stored in the storage space.

  Further, according to the present invention, a ribbon-like resistor having lead terminals attached to both ends is bent and stored in a U-shape in the storage space in the insulating case, and the space between the lead terminals in the storage space is In the method of manufacturing a cement resistor, the inner wall with which the outer surface of the ribbon-shaped resistor contacts has the same shape as the U-shape, and an insulating filler is filled inside the resistor in the storage space. The storage space of the insulating case is such that the ribbon-shaped resistor is bent in a state of having elasticity in an expanding direction so that the outer surface of the ribbon-shaped resistor is in contact with the inner wall. After the storage, the storage space is filled with an insulating filler.

  According to the present invention, since the outer surface of the ribbon-shaped resistor bent in a U shape is in contact with the inner wall of the insulating case, the heat generated in the resistor is conducted to the insulating case. Heat can be radiated to the outside, and heat dissipation can be improved. Further, since the ribbon-shaped resistor has elasticity in the expanding direction and is accommodated in the storage space of the insulating case when bent into a U-shape, the ribbon-shaped resistor and the insulating case In addition to making good contact with the inner wall, the ribbon-like resistor can be elastically held in the insulating case when the storage space is filled with the insulating filler, so the filling operation of the insulating filler is easy. Become. Since the resistor is bent in a U shape, there is no corner in the shape of the resistor, and current concentration does not occur.

  FIG. 1 shows the appearance of a first embodiment of a cement resistor according to the present invention. FIG. 1 (A) is a perspective view, FIG. 1 (B) is a front view, and FIG. 1 (C) is a side view. is there. In the figure, 1 is an insulating case, 2 is a lead terminal, and 3 is an insulating filler.

  The insulating case 1 is generally made of ceramic, but may be a material having a certain degree of mechanical strength and heat resistance, and may be made of a material other than ceramic. A storage space is formed in the insulating case 1, a resistor is stored, and the insulating filler 3 is filled. As the insulating filler 3, an insulating material such as inorganic cement or synthetic resin such as silicone resin is used. The lead terminal 2 is connected to a resistor housed in the housing space, and protrudes from the insulating case 1 with a length necessary for mounting and connecting the cement resistor.

  2 is for explaining the insulating case in FIG. 1. FIG. 2 (A) is a sectional view of only the insulating case in the sectional view taken along the line CC of FIG. 1 (C), FIG. 2 (B). These are sectional views of only the insulating case in the sectional view taken along the line BB of FIG. In the figure, the same parts as those in FIG. 4 is a storage space and 5 is an inner wall.

  The storage space 4 has a U-shaped shape having a thickness. FIG. 2A shows the U-shaped shape of the inner wall 5, and FIG. 2B shows the thickness. The U-shaped shape and thickness will be described later.

  3 is for explaining the internal structure of the cement resistor described in FIG. 1. FIG. 3A is a cross-sectional view taken along the line CC of FIG. 1C, and FIG. It is BB sectional drawing of (B). In the figure, the same parts as those in FIG. 6 is a resistor.

  The resistor 6 has a U-shape and is accommodated in the accommodation space 4 of the insulating case 1 described with reference to FIG. The lead terminal 2 is attached to the inside of both ends of the resistor 6 and protrudes from the bottom of the insulating case 1 with a necessary length. After the resistor 6 with the lead terminal 2 attached is stored in the storage space 4 of the insulating case 1, the insulating filler 3 is filled from the bottom of the insulating case 1, and the resistor 6 and the lead terminal 2 are fixed. The Since the lead terminal 2 is attached to the inside of both ends of the resistor 6, the lead terminal 2 indicates that the outer surface of the ribbon-like resistor 6 contacts the inner wall 5 (FIG. 2) of the insulating case. Without hindering, better heat dissipation can be realized.

  4A and 4B are diagrams for explaining the resistor. FIG. 4A is a plan view of the resistor with the lead terminals attached, and FIG. 4B is a resistor in a state bent in a U shape. FIG. 4C is an explanatory diagram of a U-shape. In the figure, the same parts as those in FIGS.

  The resistor 6 is a thin ribbon-shaped resistor plate made of a resistance material such as copper-nickel or nickel-chrome, and is cut so as to have a desired resistance value. Lead terminals 2 are provided at both ends. A resistance element is configured by being attached. The lead terminal 2 is preferably attached by welding such as spot welding from the viewpoint of mechanical strength and electrical connection. The resistance value of the resistance element is determined by the specific resistance value, width W, thickness D, and length L of the ribbon-shaped resistor plate.

  As shown in FIG. 4A, a portion of the resistor 6 of the resistance element in which the lead terminals 2 are attached to both ends of the resistor 6 is bent into a U shape as shown in FIG. 2 is inserted into the storage space 4 of the insulating case 1 described above. In a state where the resistor 6 is bent in a U shape, the resistor 6 itself has elasticity in a direction in which the space between the two lead terminals 2 expands due to the elasticity of the resistor itself. That is, by having the spring force in the expanding direction, the resistor 6 is inserted in the storage space 4 of the insulating case 1 in FIG. 2 as described in FIG. The U-shape is the same as the U-shape of the inner wall 5 of the inner space 4 so that the outer surface of the resistor 6 bent into the U-shape is in close contact with the inner wall 5 of the inner space 4. To touch. Therefore, the heat conduction from the resistor 6 to the insulating case 1 becomes good.

  As for the U-shaped shape of the inner wall 5 of the inner space 4 of the insulating case 1, at least the inner wall in the vicinity of the portion where the lead terminal 2 is accommodated is parallel (at right angles to the bottom surface of the insulating case 1). There may be a curved surface, and the projected shape of the curved surface may be a quadratic curve such as semicircular, semi-elliptical, parabolic, or a cubic curve. 4 (C), in the ribbon-shaped resistor 6 to be used, when the distance between the two straight portions is determined with the straight portions from the bottom as ab and cd, the portions other than the straight portions are Since it is thought that the curve shape which it takes freely is the distortion given to the resistor 6, the curve shape is preferable. However, since it is not necessary for the straight line portion to be strictly straight, it is sufficient for the U-shaped shape to be “upwardly convex curved shape having no corners when viewed from the bottom surface”. In the book, such a curved shape is called a U-shape.

  The thickness of the internal space 4 of the insulating case 1 in FIG. 2 may be a thickness that can accommodate the width W of the ribbon-like resistor 6, and may be a thickness equal to or greater than W. From the viewpoint of downsizing, it is sufficient that it is slightly larger than W.

  FIG. 5 is a process diagram for explaining a basic manufacturing method of the cement resistor described in FIG. First, a ribbon-like metal plate serving as a resistor is prepared, and cutting is performed in step S1. In the cut, the resistance value is adjusted so as to have the length L described in FIG. Of course, the material, width, and thickness of the ribbon-shaped metal plate are prepared so as to have a desired resistance value. The next step S2 is a lead terminal connecting step. In this embodiment, spot welding is used, but lead terminals can be attached to both ends of the resistor by appropriate connecting means. The resistor to which the lead terminal is attached is bent so that it can be inserted into the storage space 4 described with reference to FIG. The bending of the resistor at this time is performed in consideration of the elastic limit so that a spring force that expands between the lead terminals remains in a state where the resistor is inserted into the storage space. Therefore, the shape for bending the resistor during insertion need not be the same as the shape of the inner wall. In the state in which the resistor is inserted, the resistor can be brought into close contact with the U-shaped inner wall of the storage space by this spring force. Moreover, since the resistor can be held in the storage space by this spring force, it becomes easy to fill the cement. In the cement filling step of S4, cement is filled and cement resistance can be manufactured.

  FIG. 6 is a view for explaining a second embodiment of the cement resistor of the present invention. FIG. 6 (A) corresponds to FIG. 2 (A), and FIG. 6 (B) is FIG. 5 (B). 6C corresponds to FIG. 3A. In the figure, parts corresponding to those in FIGS.

  In the first embodiment, the lead terminal is placed inside with the resistor bent in a U shape, whereas in the second embodiment, the lead terminal is bent in a U shape. It is different in that it is on the outside in a state where Therefore, in FIG. 5A, the first embodiment and the second embodiment are the same, but when the resistor 6 is bent, the lead terminal 2 is connected to the resistor as shown in FIG. 6B. 6 to be bent outside.

  As shown in FIG. 6A, the storage space 4 of the insulating case 1 that stores the resistor 6 recedes from the inner wall where the vicinity of the lead terminal mounting portion of the resistor contacts so that the lead terminal can be stored. The escape part which was made is formed. The retraction amount may be a size that does not cause bending in the vicinity of the lead terminal mounting portion of the resistor. In FIG. 6A, a stepped-back escape portion is formed so as to have a step near the opening. Yes. Speaking of the geometrical size of the relief portion, it can be said that it is sufficient if it is equal to or larger than the width obtained by projecting the lead terminal onto a plane parallel to the plane including the two lead terminals.

  In the storage space 4 of FIG. 6 (A), as shown in FIG. 6 (B), a ribbon-like resistor 6 having lead terminals 2 attached to both ends bent in a U shape is stored. Insulating filler 3 is filled. In the housed state, as shown in FIG. 6C, no bending occurs near the lead terminal mounting portion of the resistor 6. Since the second embodiment is the same as the first embodiment except for the above description, the description thereof will be omitted.

  In the first and second embodiments described above, the lead terminal has been described as having a linear shape. However, the lead terminal of the present invention is not limited to a linear shape. It may be a shape bent into an appropriate shape such as a shape. Also, the shape of the cross section is not limited to a circle, but may be a polygon such as a quadrangle. In addition, the insulating case is provided with an opening on the bottom side where the lead terminal protrudes, and a resistor is inserted from the bottom side during manufacturing, but the front side wall where the U-shaped inner wall can be seen As the lid member, a resistor may be inserted with the front side as an opening. The lid member may be attached before or after filling with cement.

BRIEF DESCRIPTION OF THE DRAWINGS The external appearance of the 1st Example of the cement resistor of this invention is shown, FIG. 1 (A) is a perspective view, FIG.1 (B) is a front view, FIG.1 (C) is a side view. FIG. 2A is a sectional view of only the insulating case in the sectional view taken along the line CC of FIG. 1C, and FIG. 2B is a diagram for explaining the insulating case in FIG. It is sectional drawing of only the insulating case in the BB sectional drawing of (B). FIG. 3A is a cross-sectional view taken along the line CC of FIG. 1C, and FIG. 2B is a cross-sectional view of FIG. 1B. It is a BB sectional view. FIG. 4 (A) is a plan view of the resistor with the lead terminals attached, and FIG. 4 (B) is an explanatory diagram of the resistor in a U-shaped state. FIG. 4C is an explanatory diagram of a U-shape. It is process drawing for demonstrating the basic manufacturing method of the cement resistor demonstrated in FIG. FIG. 6 (A) corresponds to FIG. 2 (A), FIG. 6 (B) corresponds to FIG. 5 (B), for explaining a second embodiment of the cement resistor of the present invention. FIG. 6C corresponds to FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Insulating case, 2 ... Lead terminal, 3 ... Insulating filler, 4 ... Storage space, 5 ... Inner wall, 6 ... Resistor.

Claims (6)

In the storage space in the insulating case, a ribbon resistor having lead terminals attached to both ends is bent and stored in a U shape, and is a cement resistor filled with an insulating filler,
The inner wall where the outer surface of the ribbon-shaped resistor between the lead terminals in the storage space contacts is the same shape as the U-shape,
The cement resistor according to claim 1, wherein the ribbon-shaped resistor has elasticity in an expanding direction and is accommodated in the accommodation space when bent in the U-shape.   The cement resistor according to claim 1, wherein the lead terminal is attached to the inside of the both ends of the ribbon-shaped resistor.   The lead terminal is attached to the outside of the both ends of the ribbon-shaped resistor, and the inner wall facing the lead terminal in the storage space is not bent in the vicinity of the lead terminal attaching portion of the resistor. The cement resistor according to claim 1, wherein an escape portion that is retracted is formed. A ribbon-like resistor having lead terminals attached to both ends is bent and stored in a U-shape in the storage space in the insulating case, and the ribbon-like resistor between the lead terminals in the storage space is stored. An inner wall with which an outer surface contacts is the same shape as the U-shape, and a manufacturing method of a cement resistor in which an insulating filler is filled inside the resistor in the storage space,
The ribbon-shaped resistor is bent into a state of elasticity in the expanding direction, and is stored in the storage space of the insulating case so that the outer surface of the ribbon-shaped resistor is in contact with the inner wall. Then, the manufacturing method of the cement resistor characterized by filling the said accommodation space with an insulating filler.   The said lead terminal is attached to the inner side of the said both ends of the said ribbon-shaped resistor, The manufacturing method of the cement resistor of Claim 4 characterized by the above-mentioned.   The lead terminal is attached to the outside of the both ends of the ribbon-shaped resistor, and the inner wall facing the lead terminal in the storage space is not bent near the lead terminal mounting portion of the resistor. 5. The method of manufacturing a cement resistor according to claim 4, wherein an escape portion that is retracted is formed.

Images