JP4012916B2 - PTC element and manufacturing method thereof - Google Patents

Description

  The present invention relates to a PTC element and a manufacturing method thereof.

A PTC (Positive Temperature Coefficient) element is known as an element for protecting a circuit element from an overcurrent. The PTC element is an element whose positive temperature coefficient increases rapidly when a certain temperature region is reached. As one of such PTC elements, one described in Patent Document 1 below is known.
JP 2005-123473 A

  In the PTC element described in Patent Document 1, a terminal electrode made of a metal such as nickel is thermocompression bonded to both front and back surfaces of an element body made of an organic positive temperature characteristic composition in which conductive particles are dispersed in a crystalline polymer. It is fixed. The terminal electrodes protrude alternately from the element body, and the protruding portions are leads.

  However, when the terminal electrode is joined to the element body by thermocompression bonding, the element body that has been crimped and crushed extends to a lead that is a region other than the opposing region facing each other in a part of the terminal electrode. . Therefore, the lead is covered with the extended element body, and there is a problem that connection failure may occur when the PTC element is mounted.

  An object of the present invention is to provide a PTC element capable of suppressing the occurrence of connection failure in a terminal electrode and a method for manufacturing the same.

  A method for producing a PTC element according to the present invention is a method for producing a PTC element comprising an element body containing a resin and conductive particles, and a pair of terminal electrodes whose one surface is a rough surface. Preparing the element body material and each terminal electrode, and arranging each terminal electrode so that a part of the rough surface side of each terminal electrode faces each other, and each terminal electrode is sandwiched between regions facing each other An element in which each terminal electrode is extended from a region facing each other by the step of crimping each terminal electrode and the element body material and the step of crimping each terminal electrode and the element body material by arranging the element body material at the position. A step of cutting the extending part by introducing the tip of the cutting member from the extending part of the body material to the inside of the terminal electrode joined to the extending part, and the tip of the cutting member is the terminal electrode Each terminal electrode is in the state of being introduced inside Away from the region facing the stomach, is moved to the end of at least extended portion, characterized in that it comprises a step of forming a notch, a.

  In the method for manufacturing a PTC element according to the present invention, the distal end of the cutting member is introduced from the extended portion to the inside of the terminal electrode joined to the extended portion, so that the terminal electrodes are opposed to each other. The extension part of the element body material extending from is cut off. And the cutting member is moved to the extended part side and the edge part of the extended part at least to the edge part of the extended part with the front-end | tip of this cutting member introduced into the inside of the terminal electrode. Therefore, the extension part of the element body material that has bitten into the rough surface of the terminal electrode by crimping the element body material and the terminal electrode is removed together with the surface (rough surface) of the terminal electrode. As a result, the occurrence of connection failure in the terminal electrode is suppressed when the PTC element is mounted. In addition, since the notch is formed by moving at least the end of the extended portion while the tip of the cutting member is introduced into the terminal electrode, the terminal electrode is easily bent at the notch. Even when an external force is applied to the terminal electrode, the terminal electrode is extremely difficult to peel from the element body. Furthermore, since the extended portion of the element material extending from the region where the terminal electrodes face each other is removed, the appearance of the PTC element can be kept good.

  On the other hand, the PTC element according to the present invention is a PTC element comprising an element body containing a resin and conductive particles and a pair of terminal electrodes whose one surface is a rough surface. Arranged so that parts of the rough surface face each other, the element body is arranged at a position where each terminal electrode is sandwiched between regions facing each other, and the outer surface on the side where each terminal electrode extends is Cutout portions each having a wall surface that is the same plane as the cut surface are formed in a region other than a region where each terminal electrode is opposed to each other and a region where each terminal electrode is opposed to each other. It is characterized by being.

  In the PTC element according to the present invention, the outer surface on the side where each terminal electrode of the element body extends is a cut surface. Therefore, since the element body material extends from the region where each terminal electrode opposes and the terminal electrode is not covered, the occurrence of connection failure in the terminal electrode is suppressed when the PTC element is mounted. Here, when the force is applied to the terminal electrode when the cut surface and the wall surface of the notch portion are not the same plane and are shifted, extra stress is generated in the terminal electrode, which remains without being removed. The extended portion may be bent together with the terminal electrode due to the stress, and the terminal electrode may be peeled off from the element body. However, since each terminal electrode of the PTC element according to the present invention has a notch portion having a wall surface that is the same plane as the cut surface, the terminal electrode is easily bent at the notch portion. Even when an external force is applied to the terminal electrode, the terminal electrode is extremely difficult to peel from the element body.

  ADVANTAGE OF THE INVENTION According to this invention, the PTC element which can suppress generation | occurrence | production of the connection failure in a terminal electrode, and its manufacturing method can be provided.

  A PTC element according to an embodiment of the present invention will be described with reference to the drawings. Note that in the description, the same reference numerals are used for the same elements or elements having the same function, and redundant description is omitted.

  With reference to FIG.1 and FIG.2, the structure of the PTC element 1 which concerns on this embodiment is demonstrated. FIG. 1 is a perspective view showing a PTC element according to this embodiment. FIG. 2 is an enlarged cross-sectional view showing a part of the PTC element according to the present embodiment.

  The PTC element 1 is a polymer PTC and includes an element body 10 and a pair of terminal electrodes 12 and 14.

  The element body 10 is formed by dispersing a conductive filler in a crystalline polymer resin. Ni powder is preferably used as the conductive filler, and polyethylene resin, which is a thermoplastic resin, is preferably used as the crystalline polymer resin. The element body 10 is pressure-bonded to the terminal electrodes 12 and 14 by pressing and heating. Moreover, the side surfaces 101-104 which comprise the outer peripheral surface which is not joined to each terminal electrode 12 and 14 in the element | base_body 10 are cut surfaces.

  Each of the terminal electrodes 12 and 14 is a substantially rectangular flat plate made of, for example, Ni or Ni alloy. Each of the terminal electrodes 12 and 14 has opposing regions 121 and 141, which are regions that are partially opposed to each other, and non-facing regions 122 and 142 that are regions that do not face each other. Each of 142 is arranged so as to extend on the opposite side. The opposing regions 121 and 141 of the terminal electrodes 12 and 14 are regions that sandwich the element body 10, and the non-facing regions 122 and 142 of the terminal electrodes 12 and 14 are for mounting the PTC element 1 on other components. Has become the lead. The surfaces on the side where the terminal electrodes 12 and 14 face each other are firmly joined to the element body 10 and the terminal electrodes 12 and 14 by an anchor effect caused by the element body 10 biting into the terminal electrodes 12 and 14. As shown in FIG. 2, the surface is a rough surface on which fine unevenness is formed (in FIG. 2, the unevenness is emphasized for convenience of explanation). In addition, the thickness of each terminal electrode 12 and 14 is about 100 micrometers, for example. Moreover, the difference of the unevenness | corrugation formed in each terminal electrode 12 and 14 is about 10-50 micrometers, for example.

  Each of the terminal electrodes 12 and 14 has notches 12a and 14a, which are surfaces facing each other and part of the non-facing regions 122 and 142 are cut into a substantially concave shape with a predetermined width. is doing. The wall surfaces 12b and 14b on the element body 10 side of the notches 12a and 14a are flush with the side surfaces 101 and 102 of the element body 10, respectively. The depth D of the notches 12a and 14a is about 10 μm, for example. Further, the width L of the notches 12a and 14a is approximately the same as that of the extended portions extending from the opposing regions 121 and 141 (details will be described later), and is approximately 1.3 mm, for example.

  Next, with reference to FIGS. 3 and 4, a method for manufacturing the PTC element 1 according to the present embodiment will be described. FIG. 3 is a view showing the procedure of the method for manufacturing the PTC element according to the present embodiment. FIG. 4 is a diagram for explaining a cutting step in the method for manufacturing a PTC element according to the present embodiment. In FIG. 3, step is abbreviated as S.

  In the method for manufacturing the PTC element 1, in steps 1 to 4, an element body creating process, an arranging process, a terminal connecting process, and a cutting process are performed.

  In the element body creating step of Step 1, an element body material M to be the element body 10 (see FIGS. 1 and 2) is created. When creating the base material M, first, Ni powder that becomes a conductive filler and polyethylene resin that becomes a crystalline polymer resin are kneaded to form a block. The base material M is obtained by pressing the block into a disk shape and cutting the block so as to have a volume larger than the volume of the base body 10. At this time, the element material M is formed so that the volume of the element material M is larger than that of the element body 10 and the projected area is smaller than that of the element body 10.

  In the subsequent arrangement process of step 2, the terminal electrodes 12 and 14 and the element body material M whose one surface is a rough surface are prepared. The opposing regions 121 and 141 are opposed to each other on the rough surface side of the terminal electrodes 12 and 14, and the non-facing region 122 of the terminal electrode 12 and the non-facing region 142 of the terminal electrode 14 are opposite to each other. Arrange to extend. At this time, the element material M is disposed between the facing area 121 and the facing area 141.

  In the subsequent terminal connection step of Step 3, the terminal electrodes 12, 14 are pressure-bonded while being heated toward the base material M from the state in which the base material M is disposed between the opposing regions 121, 141, or after the heating. The terminal electrodes 12 and 14 are connected to the base material M by crimping. Then, the element body material M is crushed by the respective terminal electrodes 12 and 14, and as shown in FIG. M2 will be generated. 4A shows the extended portions M1 and M2 extending to the non-facing regions 122 and 142 of the terminal electrodes 12 and 14, the element material M extends in other directions. I'm out.

  In the subsequent cutting process of step 4, in order to cut the extended portion M <b> 1 of the base material M, first, the terminal electrodes 12 and 14 and the base material M connected in the terminal connection process of step 3 are stepped. (See FIG. 4A). At this time, one of the terminal electrodes (in FIG. 4A, the terminal electrode 12) is locked to the step portion of the positioning member 20, so that the connected terminal electrodes 12, 14 and the element body material M ( The PTC element) before the cutting of the extended portions M1 and M2 is positioned.

  Subsequently, the fixing member 30 such as a stripper is pressed from the terminal electrode 12 side, and the terminal electrodes 12 and 14 and the element body material M are fixed by the fixing means 30 (see FIG. 4B). Then, the extending part M1 extending from the facing regions 121 and 141 is cut by the cutting member 40 such as a cutter along the cutting line L1 located near the boundary between the facing region 141 and the non-facing region 142. At this time, the cutting member 40 is lowered in the direction of the arrow A in FIG. 4B, and extends from the extended portion M1 to the inside of the terminal electrode 14 joined to the extended portion M1 (for example, the terminal electrode 14). The tip of the cutting member 40 is introduced (from the surface to a depth of about 10 μm).

  Subsequently, after cutting the extension portion M1, the tip of the cutting member 40 is introduced into the terminal electrode 14 (the state shown in FIG. 4B), and on the extension portion M1 side and the terminal. The cutting member 40 is moved by the width L in the extending direction of the electrode 14 (the direction of arrow B in FIG. 4C). As a result, a notch portion 14a is formed in the non-facing region 142 of the terminal electrode 14, and the wall surface 14b of the notch portion 14a on the element material M side and the cut surface of the element material M (the side surface 101 of the element body 10). ) And the same plane. Note that the cutting member 40 is moved to at least the end portion M1a of the extended portion M1 in order to remove the element body material M that has bitten into the rough surface in the non-facing region 142 of the terminal electrode 14.

  In the cutting step, the above-described processing is also performed on the extended portion M2 and an extended portion (not shown), and each extended portion is cut to form the side surfaces 101 to 104 of the element body 10, and the terminal electrodes 12, 14 The notches 12a and 14a are formed in. Thereafter, the cut extension portions M1 and M2 are removed by vacuum suction or the like, whereby the PTC element 1 is manufactured.

  As described above, in this embodiment, the extending portions M1 and M2 are cut by introducing the tip of the cutting member 40 from the extending portions M1 and M2 to the inside of the terminal electrodes 14 and 12. . Then, with the tip of the cutting member 40 being introduced into the terminal electrodes 14, 12, at least the ends of the extending portions M 1, M 2 on the extending portions M 1, M 2 side and in the extending direction of the terminal electrodes 14, 12. The cutting member 40 is moved to the parts M1a and M2a. Therefore, the extension parts M1 and M2 of the base material M that have bitten into the rough surfaces of the terminal electrodes 12 and 14 by the crimping of the base material M and the terminal electrodes are the surfaces (roughness) of the terminal electrodes 12 and 14. Surface). As a result, when the PTC element 1 is mounted, connection failure in the terminal electrodes 12 and 14 can be extremely suppressed.

  Further, when the cut surfaces of the base material M (the side surfaces 102 and 101 of the base body 10) and the wall surfaces of the notches 12a and 14a are not coplanar, they are shifted to the terminal electrodes 12 and 14, respectively. When force is applied, extra stress is generated in the terminal electrodes 12 and 14, and the extension portions M1 and M2 that are left without being removed are bent together with the terminal electrodes 12 and 14 by the stress, so that the terminal electrodes 12 and 14 are The element 10 may be peeled off. However, in this embodiment, since the notches 12a and 14a are formed in the non-facing regions 122 and 142 of the terminal electrodes 12 and 14, respectively, the terminal electrodes 12 and 14 are easily bent at the notches 12a and 14a. Therefore, even when an external force is applied to the terminal electrodes 12 and 14, the terminal electrodes 12 and 14 are extremely difficult to peel from the element body 10.

  Moreover, in this embodiment, since the extension parts M1 and M2 of the element body material M extending from the opposing regions 121 and 141 are removed, the appearance of the PTC element 1 is good.

It is a perspective view which shows the PTC element which concerns on this embodiment. It is sectional drawing which expands and shows a part of PTC element which concerns on this embodiment. It is the figure which showed the procedure of the manufacturing method of the PTC element which concerns on this embodiment. It is a figure for demonstrating a cutting process among the manufacturing methods of the PTC element which concerns on this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... PTC element, 10 ... Element body, 12, 14 ... Terminal electrode, 12a, 14a ... Notch part, 121, 141 ... Opposing area, 122, 142 ... Non-opposing area, 30 ... Fixing member, 40 ... Cutting member M: Element body material, M1, M2: Extension part.

Claims (2)

A manufacturing method of a PTC element comprising an element body including a resin and conductive particles, and a pair of terminal electrodes whose one surface is a rough surface,
Preparing an element body material to be the element body and the terminal electrodes;
The terminal electrodes are arranged so that a part of the rough surface side of each terminal electrode faces each other, and the element body material is arranged at a position sandwiched by regions where the terminal electrodes face each other, Crimping each terminal electrode and the element material; and
The terminal joined to the extension part from the extension part of the element body material extended from the region where the terminal electrodes face each other by the step of crimping the terminal electrode and the element body material. Cutting the extension part by introducing the tip of the cutting member up to the inside of the electrode; and
In a state where the tip of the cutting member is introduced into the terminal electrode, the terminal electrode is moved to at least the end of the extending portion in a direction away from the region facing each other, and the notch is And a process for forming the PTC element. A PTC element comprising an element body including a resin and conductive particles, and a pair of terminal electrodes whose one surface is a rough surface,
Each of the terminal electrodes is disposed such that a part of the rough surface side thereof faces each other,
The element body is disposed at a position where the terminal electrodes are sandwiched between regions facing each other, and the outer surface on the side where the terminal electrodes extend is a cut surface.
A notch having a wall surface that is flush with the cut surface is formed in a region other than the region in which the terminal electrodes face each other on the surface on which the terminal electrodes face each other. A characteristic PTC element.

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