JP2020191245A - Insert molding method, breaker manufacturing method, insert molded component, and breaker - Google Patents

Abstract

To provide an insert molded component or the like that suppresses erosion of resin burrs on the side surface of a metal piece and easily obtains good connection by soldering.SOLUTION: In an insert molding method, a resin material is filled in a molding space partitioned by a first mold and a second mold, and a component in which a part of a metal piece is embedded in a resin case is molded. The insert molding method includes a recess forming step S2 of forming a recess recessed from the side surface on the side surface of the metal piece, a loading step S3 of loading a metal piece into the first mold such that the recess is located outside the molding space, a mold closing step S4 of moving the first mold or the second mold in the in-plane direction of the side surface, and sandwiching the metal piece between the first mold and the second mold, and a molding process S5 of filling the molding space closed by the first mold and the second mold with a resin material and cures the resin to mold the resin case.SELECTED DRAWING: Figure 2

Description

The present invention relates to an insert molding method for molding a part in which a part of a metal piece is embedded in a resin case.

Conventionally, a breaker in which a part of a terminal piece is embedded in a resin case is known.

Japanese Unexamined Patent Publication No. 2019-021536

In the above breaker, soldering is disclosed as a method of connecting a terminal piece and an external circuit. In order to obtain a good connection state by soldering, it is desirable that the fillet is formed by the solder that wraps around to the side surface of the terminal piece.

However, in insert molding, when the filled resin material flows out into the gap between the mold and the terminal piece, the side surface of the terminal piece is covered with the resin beam, which may hinder the formation of the fillet described above.

The present invention has been devised in view of the above circumstances, and provides an insert-molded part that suppresses erosion of resin burrs on the side surface of a metal piece and easily obtains a good connection by soldering. Is the main purpose.

The first invention of the present invention is an insert for filling a molding space partitioned by a first mold and a second mold with a resin material and molding a part in which a part of a metal piece is embedded in a resin case. In the molding method, a recess forming step of forming a recess recessed from the side surface on the side surface of the metal piece, and the metal piece being placed in the first mold so that the recess is located outside the molding space. A loading step of loading into the mold and a mold closing step of moving the first mold or the second mold in the in-plane direction of the side surface and sandwiching the metal piece between the first mold and the second mold. And the molding step of filling and curing the resin material in the molding space closed by the first mold and the second mold to mold the resin case.

In the insert molding method according to the present invention, the side surface is a first side surface arranged so as to extend from the molding space to the outside in the loading step, and a second side surface intersecting the first side surface at the outside. It is desirable that the recess is formed on the first side surface in the recess forming step.

In the insert molding method according to the present invention, it is desirable that the metal pieces are loaded so that the recesses are spaced apart from the edge of the molding space in the loading step.

In the insert molding method according to the present invention, in the recess forming step, the recess penetrates the metal piece in the direction in which the first mold or the second mold moves in the mold closing step. It is desirable to be formed.

It is desirable that the insert molding method according to the present invention further includes a metal piece forming step of forming the metal piece using a metal containing copper as a main component.

In the insert molding method according to the present invention, it is desirable that the metal piece forming step further includes a plating step of plating the surface of the metal piece with tin or silver.

The second invention of the present invention is a breaker manufacturing method for manufacturing a breaker by using an insert molding method, in which the breaker has a fixed contact and a movable contact at an elastic portion and one end of the elastic portion. A movable piece that presses the movable contact against the fixed contact to bring the movable contact into contact with the fixed contact, and a terminal piece connected to at least one of the fixed contact and the movable piece are deformed with a temperature change to form the movable piece. A thermal response element that shifts the state from a conductive state in which the movable contact contacts the fixed contact to a cutoff state in which the movable contact is separated from the fixed contact, and the fixed contact, the movable piece, the terminal piece, and the thermal response. A case for accommodating an element is provided, the terminal piece includes the metal piece formed in the first step, and the case includes the resin case formed in the fourth step.

The third invention of the present invention is an insert molded part in which a part of a metal piece is embedded in a resin case, a parting line is formed in the resin case, and the metal piece is a parting line. A recess recessed from the side surface is formed in a region of the intersecting side surfaces that protrudes from the resin case.

In the insert molded part according to the present invention, it is desirable that the recess is formed at a distance from the edge of the resin case.

The fourth invention of the present invention is a breaker including the insert molded part, which has a fixed contact and a movable contact at an elastic portion and one end of the elastic portion, and presses the movable contact against the fixed contact. By deforming the movable piece to be brought into contact with the fixed contact and the terminal piece connected to at least one of the movable pieces with a temperature change, the movable contact comes into contact with the fixed contact in the state of the movable piece. The present invention includes a heat-responsive element that shifts from a conductive state to a cut-off state in which the movable contact is separated from the fixed contact, and a case for accommodating the fixed contact, the movable piece, the terminal piece, and the heat-responsive element. The terminal piece includes the metal piece, and the case includes the resin case.

According to the first aspect of the present invention, in the recess forming step, a recess recessed from the side surface is formed in a region of the side surface of the metal piece that protrudes from the resin case. As a result, the resin material protruding from the gap between the first mold and the metal piece in the molding process is accommodated in the recess. As a result, the recess functions as a dam that blocks the outflow of the resin material, so that erosion of the resin burrs on the side surface of the metal piece is suppressed, and it is possible to easily secure an area where the surface of the metal piece is exposed on the side surface. It becomes. Therefore, in the soldering of the metal piece and the external circuit, a good connection between the metal piece and the external circuit can be easily obtained by the fillet formed on the side surface.

According to the second invention of the present invention, the erosion of the resin burrs on the side surface of the terminal piece of the breaker is suppressed, and as in the first invention, good connection between the terminal piece and the external circuit is achieved in the soldering. Easy to obtain.

According to the third aspect of the present invention, a recess recessed from the side surface is formed in a region of the side surface intersecting the parting line of the metal piece that protrudes from the resin case. Therefore, as in the first invention, good connection between the metal piece and the external circuit can be easily obtained in the soldering.

According to the fourth invention of the present invention, similarly to the second invention, good connection between the metal piece and the external circuit can be easily obtained in the soldering.

The perspective view which shows the structure of the insert molded part by one Embodiment of this invention. The flowchart which shows the procedure of the insert molding method by one Embodiment of this invention. The side view which shows the metal piece forming process of the said insert molding method. The side view which shows the recess forming process of the said insert molding method. The side view which shows the loading process of the said insert molding method. The side view which shows the mold closing process of the said insert molding method. The side view which shows the molding process of the said insert molding method. The side view which shows the mold release process of the said insert molding method. The perspective view which shows the modification of the concave part formed on the 1st side surface of the insert molded part. The perspective view before assembly which shows the structure of the breaker including the said insert molded part. The cross-sectional view which shows the said breaker in a normal charge or discharge state. A cross-sectional view showing the breaker in an overcharged state or an abnormal state. The perspective view which shows the structure of the terminal piece included in the breaker. A perspective view of the breaker viewed from the bottom side. A perspective view of a modified example of the breaker as viewed from the bottom surface side.

An insert molded part according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows the configuration of an insert molded part. The insert-molded part 100 is a part in which a part of the metal piece 120 is embedded in the resin case 110.

The resin case 110 is formed by, for example, injection molding. The resin case 110 is formed, for example, by filling and curing a resin material in a molding space partitioned by a first mold and a second mold. The insert molded part 100 of the present embodiment is formed by filling the molding space with a resin material in a state where the metal piece 120 is sandwiched and fixed by the first mold and the second mold. A parting line 111, which is a trace of the mating surface between the first mold and the second mold, is formed on the side wall of the resin case 110.

The metal piece 120 has a side surface 121 that intersects the parting line 111 and a recess 122 that is recessed from the side surface 121. In the present embodiment, as shown in FIG. 6 to be described later, the first mold 301 and the second mold 302 divided along the surface 120t on the front side (upper side in FIG. 6) of the metal piece 120 are used. The resin case 110 is molded. Therefore, the parting line 111 is formed on the same plane as the surface 120t of the metal piece 120.

The parting line may be on the same plane as the surface 120b on the back side of the metal piece 120, or may be the surface intersecting the side surface 121 of the metal piece 120. Further, from the viewpoint of manufacturing (easiness of fixing the metal piece 120 and simplification of the configurations of the first mold and the second mold), it is preferable that the metal piece 120 is on the same plane as the surface 120t or the surface 120b.

The recess 122 is formed in a region of the side surface 121 that protrudes from the side wall of the resin case 110. The recess 122 is formed so as to have, for example, an arcuate or polygonal contour in a plan view of the metal piece 120 when viewed from the thickness direction.

As described above, in the molding of the insert molded part 100, the resin material may protrude into the gap between the first mold 301 and the metal piece 120, and the resin beam 105 may be formed on the side surface 121. However, according to the insert molded part 100 of the present embodiment, when the resin case 110 is molded, the resin material protruding from the gap between the first mold 301 and the metal piece 120 is housed in the recess 122. As a result, the recess 122 functions as a dam that blocks the outflow of the resin material, so that the erosion of the resin beam 105 on the side surface 121 of the metal piece 120 is suppressed, and the side surface 121 (metal surface) of the metal piece 120 is exposed. Can be easily secured. Therefore, in the soldering of the metal piece 120 and the external circuit 200, a good connection between the metal piece 120 and the external circuit 200 can be easily obtained by the fillet 210 formed on the side surface 121.

It is desirable that the recess 122 is formed at a distance G from the edge of the resin case 110. As a result, the resin material supplied from the molding space to the recess 122 is suppressed, and the recess 122 is suppressed from being filled with the resin material. From the above viewpoint, it is desirable that the recess 122 is formed, for example, at a distance G equal to or greater than the thickness of the metal piece 120 from the edge of the resin case 110.

FIG. 2 shows the procedure of the insert molding method according to the embodiment of the present invention. In this insert molding method, a resin material is filled in a molding space partitioned by a first mold 301 and a second mold 302, and an insert molding part 100 in which a part of a metal piece 120 is embedded in a resin case 110 is formed. It is a method for molding.

This insert molding method includes a metal piece forming step S1, a recess forming step S2, a loading step S3, a mold closing step S4, a molding step S5, and a mold removing step S6.

FIG. 3 shows the metal piece forming step S1. In the metal piece forming step S1, for example, a plate-shaped metal material containing copper as a main component is punched out using a press die or the like to form a metal piece 120 having a side surface 121.

FIG. 4 shows the recess forming step S2. In the recess forming step S2, a recess 122 that is depressed from the side surface 121 is formed on the side surface 121 of the metal piece 120. The recess forming step S2 may be performed at the same time as the metal piece forming step S1.

FIG. 5 shows the loading step S3. In the loading step S3, the metal piece 120 is loaded into the first mold 301. The first mold 301 is formed with a recess 304 on which the metal piece 120 is loaded and a recess 305 for forming the molding space 303. The metal piece 120 is loaded into the recess 304 so that the recess 122 is located outside the molding space 303.

FIG. 6 shows the mold closing step S4. In the mold closing step S4, the second mold 302 is moved toward the first mold 301, and the mold is closed. In the mold closing step S4, the first mold 301 may be moved toward the second mold 302. The moving direction of the second mold 302 or the first mold 301 is the in-plane direction of the side surface 121 (an arbitrary direction that does not intersect the side surface 121, that is, a direction parallel to the side surface 121). In the mold closing step S4, the metal piece 120 is sandwiched and fixed by the first mold 301 and the second mold 302.

The second mold 302 is formed with a recess 306 for forming the molding space 303. The mold closing step S4 closes the first mold 301 and the second mold 302, and the molding space 303 created by the recess 305 and the recess 306 is partitioned.

FIG. 7 shows the molding step S5. In the molding step S5, the resin case 110 is molded by filling the molding space 303 with the resin material R and curing it.

FIG. 8 shows the mold release step S6. In the mold release step S6, the second mold 302 is separated from the first mold 301 to open the mold, and the insert molded part 100 is released.

According to this insert molding method, in the recess forming step S2, a recess 122 that is recessed from the side surface 121 is formed in a region of the side surface 121 of the metal piece 120 that is set to protrude from the resin case 110. As a result, the resin material R protruding into the gap between the first mold 301 and the metal piece 120 in the molding step S5 is accommodated in the recess 122 (see FIG. 1).

As a result, the erosion of the resin beam 105 on the side surface 121 of the metal piece 120 is suppressed, and it is possible to easily secure a region on the side surface 121 where the surface of the metal piece 120 is exposed. Therefore, in the soldering of the metal piece 120 and the external circuit 200, a good connection between the metal piece 120 and the external circuit 200 can be easily obtained by the fillet 210 formed on the side surface 121.

As shown in FIG. 1, the side surface 121 includes a first side surface 125 and a second side surface 126 (see FIG. 1). A part of the first side surface 125 is embedded in the resin case 110, and the other part protrudes from the resin case 110. The second side surface 126 intersects the first side surface 125 outside the resin case 110.

In the loading step S3, the metal piece so that the first side surface 125 extends from the molding space 303 to the outside of the molding space 303, and the second side surface 126 intersects the first side surface 125 outside the molding space 303. 120 is arranged.

It is desirable that the recess 122 is formed on the first side surface 125 in the recess forming step S2. According to such a configuration, since the fillet 210 is easily formed at least over the entire second side surface 126, a good connection between the metal piece 120 and the external circuit 200 can be easily obtained.

In the loading step S3, it is more desirable that the metal piece 120 is loaded so that the recess 122 is spaced away from the edge of the molding space 303. As a result, the resin material supplied from the molding space 303 to the recess 122 is suppressed. It is more desirable that the interval G is set to, for example, the thickness of the metal piece 120 or more. With such a configuration, the resin material supplied from the molding space 303 to the recess 122 is more effectively suppressed.

In the recess forming step S2, it is desirable that the recess 122 is formed so as to penetrate the metal piece 120 in the direction in which the first mold 301 or the second mold 302 moves in the mold closing step S4. Such a recess 122 can be easily formed using a press die. Further, such a recess 122 makes it possible to easily secure a capacity for accommodating the resin material.

FIG. 9 shows a recess 122A which is a modification of the recess 122 formed on the first side surface 125. The recess 122A is formed by striking or cutting a part of the first side surface 125 in the out-of-plane direction of the first side surface 125. Such a recess 122A also accommodates the resin material R protruding into the gap between the first mold 301 and the metal piece 120 in the molding step S5, and suppresses the erosion of the resin beam 105.

The metal piece forming step S1 may further include a plating step of plating tin or silver on the surface of the metal piece 120. The metal piece 120 manufactured through the plating process has improved solder wettability and can be easily soldered to the external circuit 200.

In the insert molded part 100 manufactured through the metal piece forming step S1 to the mold release step S6 shown in FIGS. 3 to 8, the surface 120b of the metal piece 120 is also exposed from the bottom surface of the resin case 110. Therefore, the entire region where the surface 120b is exposed from the metal piece 120 may be used for soldering. According to such a form, the protruding length of the metal piece 120 from the edge of the resin case 110 is shortened, and it becomes easy to reduce the size of the insert molded part 100.

A breaker according to another embodiment of the present invention will be described with reference to the drawings. 10 to 12 show the configuration of the breaker 1. The breaker 1 includes an insert molded part 100, and is mounted on an electric device or the like as a component that protects the electric device from an excessive temperature rise or overcurrent.

The breaker 1 includes a fixed contact 20, terminal pieces 2 and 3, a movable piece 4 having a movable contact 41 at the tip, a heat-responsive element 5 that deforms with a temperature change, and a PTC (Positive Temperature Coefficient) thermistor. It is composed of 6 and a case 10 for accommodating terminal pieces 2 and 3, a movable piece 4, a heat-responsive element 5, and a PTC thermistor 6. The case 10 is composed of a case body (first case) 7, a lid member (second case) 8 mounted on the upper surface of the case body 7, and the like.

The fixed contact 20 is formed by clad, plating, or coating a highly conductive material such as a copper-silver alloy or a gold-silver alloy in addition to a silver, nickel, nickel-silver alloy. The fixed contact 20 is formed at a position facing the movable contact 41 of the terminal piece 2, and is exposed from a part of the opening 73a formed inside the case body 7 to the accommodating recess 73 of the case body 7.

The terminal pieces 2 and 3 are formed by, for example, pressing a metal plate containing copper or the like as a main component (in addition, a metal plate such as a copper-titanium alloy, nickel silver, or brass), and are inserted into the case body 7. It is embedded by molding.

The terminal piece 2 has a first part 21 on which the fixed contact 20 is formed and a second part 22 connected to an external circuit. The first part 21 and the second part 22 are arranged in parallel with the bottom surface of the case main body 7, and are arranged in a staggered manner via a step bending portion 23 (see FIG. 13). In the present embodiment, the back surface 2b of the second part 22 coincides with the bottom surface of the case body 7.

The terminal piece 2 has a step-bent portion 25 bent in a stepped shape (crank-shaped in a side view) and a support portion 26 for supporting the PTC thermistor 6. The step bending portion 25 connects the first portion 21 and the support portion 26, and arranges the first portion 21 and the support portion 26 at different heights. The PTC thermistor 6 is placed on a convex protrusion (dowel) 26a formed at three positions on the support portion 26, and is supported by the protrusion 26a.

In the present application, unless otherwise specified, in the terminal piece 2, the front surface (that is, the upper top surface in FIG. 10) on which the fixed contact 20 is formed is the surface 2t, and the opposite surface (that is, the back surface). In FIG. 10, the lower bottom surface) is described as the surface 2b (see FIG. 13). The same applies to other parts such as the terminal piece 3, the movable piece 4, the heat-responsive element 5, the case 10, and the like.

The second part 22 is exposed to the outside of the case 10 on the surface 2b. As a result, the second part 22 and the external circuit can be electrically connected. For example, a soldering method is applied to the connection between the second part 22 and the external circuit. The second part 22 and the external circuit are soldered in a region including the surface 2b of the second part 22. Therefore, it is desirable that the fillet 210 (see FIG. 1) is formed by the solder wrapping around the side surface 27 of the second portion 22 protruding from the case 10.

The terminal piece 3 has a first part 31 electrically connected to the movable piece 4 and a second part 32 connected to an external circuit. The first part 31 and the second part 32 are arranged in parallel with the bottom surface of the case main body 7, and are arranged in a staggered manner via the step bending portion 33. In the present embodiment, the back surface 3b in the second part 32 coincides with the bottom surface of the case body 7.

The front surface 3t of the first part 31 is exposed from the opening 73b provided inside the case body 7 to the accommodating recess 73 of the case body 7, and is electrically connected to the movable piece 4.

Similar to the terminal piece 2, the second part 32 of the terminal piece 3 is exposed to the outside of the case 10 on the back surface 3b. As a result, the second part 32 of the terminal piece 3 and the external circuit can be electrically connected. For example, a soldering method is applied to the connection between the second part 32 and the external circuit. The second part 32 and the land of the external circuit are soldered in the region including the surface 32b of the second part 32.

The movable piece 4 is formed by pressing a plate-shaped metal material containing copper or the like as a main component. The movable piece 4 is formed in an arm shape symmetrical with respect to the center line in the longitudinal direction.

A movable contact 41 is formed at one end of the movable piece 4. The movable contact 41 is formed on the back surface of the movable piece 4 with the same material as the fixed contact 20, and is joined to the tip end portion of the movable piece 4 by a technique such as welding, clad, or crimping.

At the other end of the movable piece 4, a connecting portion 42 that is electrically connected to the first portion 31 of the terminal piece 3 is formed. The first portion 31 of the terminal piece 3 and the connecting portion 42 of the movable piece 4 are fixed by, for example, laser welding. Laser welding is a welding method in which works are joined to each other by irradiating the works (corresponding to the terminal pieces 3 and the movable pieces 4 in the present embodiment) with laser light and locally melting and solidifying the works. On the surface of the work irradiated with the laser beam, a laser welding mark having a form different from the welding mark by another welding method (for example, resistance welding using Joule heat) is formed.

The movable piece 4 has an elastic portion 43 between the movable contact 41 and the connecting portion 42. The elastic portion 43 extends from the connecting portion 42 to the side of the movable contact 41. As a result, the connecting portion 42 is provided on the side opposite to the movable contact 41 with the elastic portion 43 interposed therebetween.

The movable piece 4 is fixed by being fixed to the first portion 31 of the terminal piece 3 at the connecting portion 42, and the movable contact 41 formed at the tip thereof is formed by elastically deforming the elastic portion 43 of the fixed contact 20. The terminal piece 2 and the movable piece 4 can be energized by being pressed to the side and coming into contact with each other. Since the movable piece 4 and the terminal piece 3 are electrically connected at the first part 31 and the connecting part 42, the terminal piece 2 and the terminal piece 3 can be energized.

The movable piece 4 is curved or bent by press working in the elastic portion 43. The degree of bending or bending is not particularly limited as long as the heat-responsive element 5 can be accommodated, and may be appropriately set in consideration of the elastic force at the operating temperature and the return temperature, the pressing force of the contact, and the like. Further, a pair of protrusions (contact portions) 44a and 44b are formed on the second surface of the elastic portion 43 so as to face the heat-responsive element 5. The protrusions 44a and 44b come into contact with the heat-responsive element 5, and the deformation of the heat-responsive element 5 is transmitted to the elastic portion 43 via the protrusions 44a and 44b (see FIG. 12).

The heat-responsive element 5 has an initial shape curved in an arc shape, and is formed by laminating thin plate materials having different coefficients of thermal expansion. When the operating temperature is reached due to overheating, the curved shape of the heat-responsive element 5 reversely warps with a snap motion, and is restored when the temperature drops below the return temperature due to cooling. The initial shape of the heat-responsive element 5 can be formed by press working. The material and shape of the heat-responsive element 5 are particularly limited as long as the elastic portion 43 of the movable piece 4 is pushed up by the reverse warp operation of the heat-responsive element 5 at the desired temperature and is restored by the elastic force of the elastic portion 43. However, from the viewpoint of productivity and efficiency of reverse warpage operation, a rectangular shape is desirable, and a rectangular shape close to a square is desirable in order to efficiently push up the elastic portion 43 while being small. As the material of the thermal reaction element 5, for example, nickel silver, brass, stainless steel such as copper-nickel-manganese alloy or nickel-chromium-iron alloy on the high expansion side and iron-nickel alloy on the low expansion side. Two types of materials having different coefficients of thermal expansion, which are made of various alloys such as steel, are laminated and used in combination according to required conditions.

The PTC thermistor 6 is arranged between the support portion 26 of the terminal piece 2 and the heat-responsive element 5. That is, the support portion 26 is located directly below the heat-responsive element 5 with the PTC thermistor 6 in between. When the energization between the terminal piece 2 and the movable piece 4 is cut off by the reverse warp operation of the heat-responsive element 5, the current flowing through the PTC thermistor 6 increases. If the PTC thermistor 6 is a positive characteristic thermistor whose resistance value increases as the temperature rises and limits the current, the type can be selected according to the needs such as operating current, operating voltage, operating temperature, and recovery temperature. The material and shape are not particularly limited as long as these properties are not impaired. In this embodiment, a ceramic sintered body containing barium titanate, strontium titanate, or calcium titanate is used. In addition to the ceramic sintered body, a so-called polymer PTC in which conductive particles such as carbon are contained in the polymer may be used.

The case body 7 and the lid member 8 constituting the case 10 are molded from a thermoplastic resin such as flame-retardant polyamide, polyphenylene sulfide (PPS) having excellent heat resistance, a liquid crystal polymer (LCP), and polybutylene terephthalate (PBT). Has been done. A material other than the resin may be applied as long as the characteristics equal to or higher than those of the above-mentioned resin can be obtained.

The case body 7 is formed with a storage recess 73, which is an internal space for housing the movable piece 4, the heat-responsive element 5, the PTC thermistor 6, and the like. The accommodating recess 73 has openings 73a and 73b for accommodating the movable piece 4, an opening 73c for accommodating the movable piece 4 and the heat-responsive element 5, an opening 73d for accommodating the PTC thermistor 6, and the like. doing. The movable piece 4 and the edge of the heat-responsive element 5 incorporated in the case body 7 are brought into contact with each other by a frame formed inside the accommodating recess 73, and are guided when the heat-responsive element 5 is reversely warped. ..

A cover piece 9 is embedded in the lid member 8 by insert molding. The cover piece 9 is formed by pressing a metal plate containing copper or the like as a main component or a metal plate such as stainless steel as described above. As shown in FIGS. 11 and 12, the cover piece 9 appropriately contacts the movable piece 4 to regulate the movement of the movable piece 4, and also to reduce the rigidity and strength of the lid member 8 and thus the case 10 as a housing. It contributes to the miniaturization of the breaker 1 while increasing it. Resin is arranged on the outer surface side of the cover piece 9.

As shown in FIG. 1, the lid member 8 closes the openings 73a, 73b, 73c, etc. of the case body 7 accommodating the terminal pieces 2, 3, the movable piece 4, the heat reaction element 5, the PTC thermistor 6, and the like. , Attached to the case body 7. The case body 7 and the lid member 8 are joined by, for example, ultrasonic welding. At this time, the case main body 7 and the lid member 8 are continuously joined over the entire circumference of each outer edge portion, and the airtightness of the case 10 is improved. As a result, the internal space of the case 10 provided by the accommodating recess 73 is sealed, and parts such as the movable piece 4, the heat-responsive element 5, and the PTC thermistor 6 can be shielded from the outside atmosphere of the case 10 and protected.

FIG. 11 shows the operation of the breaker 1 in a normal charging or discharging state. In a normal charging or discharging state, the heat-responsive element 5 maintains its initial shape (before reverse warpage). The cover piece 9 is provided with a protruding portion 91 that comes into contact with the top portion 43a of the movable piece 4 and presses the top portion 43a toward the heat-responsive element 5. When the protruding portion 91 presses the top portion 43a, the elastic portion 43 is elastically deformed, and the movable contact 41 formed at the tip thereof is pressed toward the fixed contact 20 and comes into contact with the elastic portion 43. As a result, the terminal pieces 2 and 3 of the breaker 1 are electrically connected to each other through the elastic portion 43 of the movable piece 4. The elastic portion 43 of the movable piece 4 and the heat-responsive element 5 may come into contact with each other, and the movable piece 4, the heat-responsive element 5, the PTC thermistor 6, and the terminal piece 2 may be electrically connected as a circuit. However, since the resistance of the PTC thermistor 6 is overwhelmingly larger than the resistance of the movable piece 4, the current flowing through the PTC thermistor 6 is substantially larger than the amount flowing through the fixed contact 20 and the movable contact 41. It can be ignored.

FIG. 12 shows the operation of the breaker 1 in an overcharged state or an abnormal state. When the temperature becomes high due to overcharging or abnormality, the heat-responsive element 5 that has reached the operating temperature reversely warps, and the elastic portion 43 of the movable piece 4 is pushed up to separate the fixed contact 20 and the movable contact 41. The operating temperature of the heat-responsive element 5 when the heat-responsive element 5 is deformed inside the breaker 1 and pushes up the movable piece 4 is, for example, 70 ° C. to 90 ° C. At this time, the current flowing between the fixed contact 20 and the movable contact 41 is cut off, and a small leakage current flows through the heat-responsive element 5 and the PTC thermistor 6. The PTC thermistor 6 continues to generate heat as long as such a leakage current flows, and the resistance value is drastically increased while maintaining the heat responding element 5 in a reverse warp state. Therefore, the current is a path between the fixed contact 20 and the movable contact 41. There is only a small amount of leakage current as described above (which constitutes a self-holding circuit). This leakage current can be used for other functions of the safety device.

When the overcharged state is released or the abnormal state is resolved, the heat generated by the PTC thermistor 6 also subsides, and the heat responding element 5 returns to the return temperature and returns to the original initial shape. Then, the elastic contact force of the elastic portion 43 of the movable piece 4 causes the movable contact 41 and the fixed contact 20 to come into contact with each other again, the circuit is released from the cutoff state, and returns to the conductive state shown in FIG.

As shown in FIG. 10, the breaker 1 includes an insert molded part 100 in a part of the configuration. In the breaker 1 of the present embodiment, the case body 7 in which the terminal pieces 2 and 3 are embedded corresponds to the insert molded part 100. That is, the terminal pieces 2 and 3 correspond to the metal pieces 120, and the case body 7 corresponds to the resin case 110. Similar to the resin case 110, a parting line 75, which is a trace of the mating surface between the first mold and the second mold, is formed on the side wall of the case body 7. Of the terminal pieces 2 and 3, for the parts not described below, the above-described structure of the metal piece 120 is adopted, and the same effect is obtained.

FIG. 13 shows terminal pieces 2 and 3. The terminal piece 2 has a side surface 27 intersecting with the parting line 75 (see FIG. 10) and a recess 28 recessed from the side surface 27.

The side surface 27 includes a first side surface 27a and a second side surface 27b. A part of the first side surface 27a is embedded in the case body 7, and the other part protrudes from the case body 7. The second side surface 27b intersects the first side surface 27a outside the case body 7.

The recess 28 is formed in a region of the side surface 27 that protrudes from the side wall of the case body 7. Like the recess 122, the recess 28 is preferably formed on the first side surface 27a. The recess 28 is formed so as to have, for example, an arc-shaped or polygonal contour in a plan view seen from the thickness direction of the terminal piece 2.

In the method of manufacturing the breaker 1, the method of molding the case body 7 is the same as the method of molding the insert molded part 100. That is, the case body 7 is formed through the metal piece forming step S1, the recess forming step S2, the loading step S3, the mold closing step S4, the molding step S5, and the mold release step S6 shown in FIGS. 2 to 8. The step bending portions 23, 25, 33 are formed, for example, in the metal piece forming step S1. Further, the first mold 301 and the second mold 302 are formed in a shape corresponding to the terminal pieces 2, 3 and the case body 7.

FIG. 14 is a perspective view of the breaker 1 as viewed from the bottom surface side. The second part 22 of the terminal piece 2 and the second part 32 of the terminal piece 3 are arranged near the four corners of the case body 7.

The second portion 22 is formed so as to project from the side wall of the case main body 7 in the lateral direction D2 of the movable piece 4, and the recess 28 is provided on the first side surface 27a. The second portion 32 is also formed so as to project from the side wall of the case body 7 in the lateral direction D2 of the movable piece 4, and a recess 38 is provided on the first side surface 37a.

According to the breaker 1 of the present embodiment, when the case body 7 is molded, the resin material protruding from the gap between the first mold and the terminal piece 2 is housed in the recess 28. As a result, the recess 28 functions as a dam that blocks the outflow of the resin material, so that the erosion of the resin beam 105 (see FIG. 1) on the side surface 27 of the terminal piece 2 is suppressed, and the side surface 27 of the terminal piece 2 is exposed. The area can be easily secured. Therefore, in the soldering of the terminal piece 2 and the external circuit 200, a good fillet is formed on the side surface 27, and a good connection between the terminal piece 2 and the external circuit 200 can be easily obtained. Further, the point that a good fillet is formed on the second side surface 27b by providing the recess 28 on the first side surface 27a is also the same as the insert molded part 100.

Similarly, the terminal piece 3 also has a side surface 37 that intersects the parting line 75 and a recess 38 that is recessed from the side surface 37. When the case body 7 is molded, the resin material is housed in the recess 28, and the area where the side surface 37 of the terminal piece 3 is exposed can be easily secured, and the terminal piece 3 and the external circuit 200 are well connected. Is easily obtained as in the case of the terminal piece 2. Further, the point that a good fillet is formed on the second side surface 37b by providing the recess 38 on the first side surface 37a is also the same as that of the insert molded part 100.

Further, the distance between the recesses 28 and 38 from the edge of the case body 7 is the same as the above distance G.

FIG. 15 is a perspective view of the breaker 1A, which is a modified example of the breaker 1, as viewed from the bottom surface side. The above-described configuration of the breaker 1 can be adopted for the portion of the breaker 1A that is not described below.

The breaker 1A is different from the breaker 1 in that the second portion 22A of the terminal piece 2 and the second portion 32A of the terminal piece 3 are formed so as to project from the side wall of the case body 7 in the longitudinal direction D1 of the movable piece 4. It is different. A recess 28 is provided on the first side surface 27a of the second part 22A. On the other hand, a recess 38 is provided on the first side surface 37a of the second portion 32A.

Although the insert molding method and the like of the present invention have been described in detail above, the present invention is not limited to the specific embodiment described above, and is modified to various embodiments. That is, in the insert molding method of the present invention, at least, the recess forming step S2 for forming the recess 122 recessed from the side surface 121 on the side surface 121 of the metal piece 120 and the recess 122 are located outside the molding space 303. The loading step S3 for loading the metal piece 120 into the first mold 301 and the first mold 301 or the second mold 302 are moved in the in-plane direction of the side surface 121 to move the metal piece 12 into the first mold 301. A mold closing step S4 sandwiched by the second mold 302 and a molding step of filling the molding space 303 closed by the first mold 301 and the second mold 302 with the resin material R and curing the resin case 110. It suffices to include S5. For example, the present invention can be applied to various insert molded parts 100 other than the case body 7 of the breaker 1.

Further, although the breaker 1 of the present embodiment has a self-holding circuit by the PTC thermistor 6, it can be applied even if such a configuration is omitted. It is also applicable to a breaker in which a movable piece and a heat-responsive element are integrated, for example, in a form in which the movable piece is formed of a metal material such as bimetal.

1 Breaker 1A Breaker 2 Terminal piece 3 Terminal piece 4 Movable piece 5 Heat-responsive element 6 PTC thermistor 7 Case body (resin case)
10 Case 12 Metal piece 20 Fixed contact 27 Side 27a First side 27b Second side 28 Recess 37 Side 37a First side 37b Second side 38 Recess 41 Movable contact 43 Elastic part 75 Parting line 100 Insert molded part 110 Resin case 111 Parting line 120 Metal piece 121 Side surface 122 Recession 122A Recession 125 First side surface 126 Second side surface 200 External circuit 210 Fillet 301 First mold 302 Second mold 303 Molding space R Resin material S1 Metal piece forming process S2 Recessing process S3 Loading process S4 Mold closing process S5 Molding process S6 Mold release process

Claims (10)

It is an insert molding method for filling a resin material in a molding space partitioned by a first mold and a second mold and molding a part in which a part of a metal piece is embedded in a resin case.
A recess forming step of forming a recess recessed from the side surface on the side surface of the metal piece,
A loading step of loading the metal piece into the first mold so that the recess is located outside the molding space.
A mold closing step of moving the first mold or the second mold in the in-plane direction of the side surface and sandwiching the metal piece between the first mold and the second mold.
The molding process includes a molding step of filling and curing a resin material in the molding space closed by the first mold and the second mold to mold the resin case.
Insert molding method. The side surface includes a first side surface arranged so as to extend from the molding space to the outside in the loading step, and a second side surface intersecting the first side surface at the outside.
The insert molding method according to claim 1, wherein the recess is formed on the first side surface in the recess forming step. The insert molding method according to claim 1 or 2, wherein in the loading step, the metal pieces are loaded so that the recesses are spaced apart from the edge of the molding space. The recess according to claim 1 to 3, wherein in the recess forming step, the recess is formed so as to penetrate the metal piece in the direction in which the first mold or the second mold moves in the mold closing step. The insert molding method according to any one. The insert molding method according to any one of claims 1 to 4, further comprising a metal piece forming step of forming the metal piece using a metal containing copper as a main component. The insert molding method according to claim 5, wherein the metal piece forming step further includes a plating step of plating tin or silver on the surface of the metal piece. A method for manufacturing a breaker by using the insert molding method according to any one of claims 1 to 6.
The breaker has a fixed contact, an elastic portion, and a movable piece having a movable contact at one end of the elastic portion and pressing the movable contact against the fixed contact to bring the movable contact into contact with the fixed contact, and at least the fixed contact and the movable piece. A terminal piece connected to one of them and a state in which the movable contact is separated from the fixed contact from a conductive state in which the movable contact contacts the fixed contact by being deformed with a temperature change. A heat-responsive element to be transferred to the above, and a case for accommodating the fixed contact, the movable piece, the terminal piece, and the heat-responsive element.
The terminal piece includes the metal piece in which the recess is formed in the recess forming step.
The case includes the resin case formed in the molding process.
How to make a breaker. A part of the metal piece is an insert molded part embedded in a resin case.
A parting line is formed on the resin case.
The metal piece is an insert-molded part in which a recess recessed from the side surface is formed in a region of the side surface intersecting with the parting line that protrudes from the resin case. The insert-molded part according to claim 8, wherein the recess is formed at a distance from the edge of the resin case. A breaker comprising the insert-molded part according to claim 8 or 9.
A fixed contact, a movable piece having a movable contact at an elastic portion and one end of the elastic portion, and pressing the movable contact against the fixed contact to make contact with the fixed contact, and at least one of the fixed contact and the movable piece are connected. Heat that shifts the state of the movable piece from the conductive state in which the movable contact contacts the fixed contact to the cutoff state in which the movable contact separates from the fixed contact by deforming with the terminal piece. A response element and a case for accommodating the fixed contact, the movable piece, the terminal piece, and the heat response element are provided.
The terminal piece includes the metal piece and contains the metal piece.
The case is a breaker including the resin case.

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