JP6781376B2 - Circuit board manufacturing method - Google Patents

Description

The present invention relates to a method for manufacturing a circuit board.

In a circuit board manufactured by mounting an electronic component on a printed wiring board, the mounted electronic component may generate abnormal heat during its operation, leading to ignition. In order to solve such a problem, for example, the following patent documents The current breaker disclosed in 1 is known. In this current breaker, the support portion on the second mounting portion side is inserted into the through hole of the printed wiring board while an external force is applied to the spring portion so that the second mounting portion is brought into contact with the wiring pattern of the printed wiring board. In this state, the support portion is separated from the second mounting portion by soldering the second mounting portion to the wiring pattern and then cutting the cut portion. As a result, the soldering work of the second mounting portion or the like to the printed wiring board can be performed without using a special jig or tool.

Japanese Unexamined Patent Publication No. 2005-038675

By the way, in recent years, printed wiring boards are often mounted by SMD (surface mount component), and even when a configuration for preventing abnormal heat generation of mounted electronic components is provided on the printed wiring board, it is automatically mounted. A possible configuration is required. However, in the configuration disclosed in Patent Document 1, it is necessary to insert the support portion into the through hole of the printed wiring board and solder it, and then cut the cut portion, which is very applicable to the automation of mounting. There is a problem that it is difficult. That is, since it is necessary to mount the current breaker in a state where the spring force is generated on the printed wiring board, it is necessary to mount it manually by the operator, which causes a problem of productivity.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a configuration capable of increasing the productivity of a circuit board while preventing abnormal heat generation of mounted electronic components. is there.

In order to achieve the above object, in the invention of claim 1 described in the claims,
A circuit in which conductors (30, 30a, 30b) for protecting the electronic component (20) are provided between the power supply paths (50) of the electronic component (20) mounted on the printed wiring board (11). A method for manufacturing the substrate (10).
A step of soldering the conductor between the power supply paths,
A step of elastically deforming the conductor after the solder bonding is completed,
It is characterized by having.

Further, in the invention of claim 3,
A circuit board (60, 60a) provided with a conductor (60, 60a) for protecting the electronic component (20) between the power supply paths (50) of the electronic component (20) mounted on the printed wiring board (11). 10a) is the manufacturing method.
A step of elastically deforming the conductor using an urging member (110, 110a),
A step of solder-bonding the elastically deformed conductor between the power supply paths, and
A step of removing the urging member from the conductor after the solder bonding is completed,
Equipped with a,
In the conductor, a portion of the power supply path on the side solder-bonded to the solder away from the electronic component is more easily elastically deformed than the portion solder-bonded to the solder on the electronic component side. It is characterized by Rukoto.
The reference numerals in the parentheses indicate the correspondence with the specific means described in the embodiments described later.

In the invention of claim 1, a circuit board is manufactured by solder-bonding a conductor between power supply paths and elastically deforming the conductor after the solder-bonding is completed. As a result, when abnormal heat generation occurs in the electronic component, the abnormal heat generation is transmitted from the electronic component to the solder on the electronic component side of the conductor via the power supply path, and the solder melts. As a result, the holding force of the solder on the conductor on the electronic component side is released, and the conductor tries to restore the original shape before elastic deformation. At that time, since the solder on the anti-electronic component side of the conductor is not melted, the conductor is restored to its original shape based on the solder on the anti-electronic component side, and is transmitted from the power supply path on the electronic component side. It becomes a separated state. By separating the conductor and the power supply path on the electronic component side in this way, the power supply to the electronic component is stopped, so that abnormal heat generation of the mounted electronic component can be prevented. In particular, since it is only necessary to elastically deform the conductor after the solder bonding is completed, there is no need for a work process that requires manual work such as cutting a predetermined portion of the conductor, and automation can be easily supported. it can. Therefore, it is possible to increase the productivity of the circuit board while preventing abnormal heat generation of the mounted electronic component.

In the invention of claim 2, after the solder bonding is completed, the central portion side in the longitudinal direction of the conductor is pressed against the mounting surface side of the printed wiring board to be plastically deformed, whereby the end side in the longitudinal direction of the conductor is elastically deformed. Let me. In this way, by plastically deforming the central portion side in the longitudinal direction of the conductor and elastically deforming the end side in the longitudinal direction, the end side in the longitudinal direction that was joined to the solder at the time of solder melting moves to the conductor. Since the power supply path on the electronic component side can be easily separated, abnormal heat generation of the mounted electronic component can be reliably prevented.

In the invention of claim 3, a conductor elastically deformed by using an urging member is solder-bonded between power supply paths, and the urging member is removed from the conductor after the solder bonding is completed to form a circuit board. To manufacture. As a result, when abnormal heat generation occurs in the electronic component, the abnormal heat generation is transmitted from the electronic component to the solder on the electronic component side of the conductor via the power supply path, and the solder melts. As a result, the holding force of the solder on the conductor on the electronic component side is released, and the conductor tries to restore the original shape before elastic deformation. At that time, since the solder on the anti-electronic component side of the conductor is not melted, the conductor is restored to its original shape based on the solder on the anti-electronic component side, and is transmitted from the power supply path on the electronic component side. It becomes a separated state. By separating the conductor and the power supply path on the electronic component side in this way, the power supply to the electronic component is stopped, so that abnormal heat generation of the mounted electronic component can be prevented. In particular, since it is only necessary to remove the urging member after solder joining, there is no need for a work process that requires manual work such as cutting a predetermined portion of the conductor, and automation can be easily supported. Therefore, it is possible to increase the productivity of the circuit board while preventing abnormal heat generation of the mounted electronic component.
In particular, in the conductor, the portion of the conductor that is solder-bonded to the solder away from the electronic component is more easily elastically deformed than the portion that is solder-bonded to the solder on the electronic component side. .. Therefore, when the solder on the electronic component side melts, the portion solder-bonded to the solder on the electronic component side becomes the electronic component side due to deformation at the portion solder-bonded to the solder away from the electronic component. Since it is far away from the power supply path of the above, it is possible to more reliably prevent abnormal heat generation of the mounted electronic component.

In the invention of claim 4, the conductor is made of copper or phosphor bronze formed in a flat plate shape. As a result, since the conductor has both springiness and solderability, the solder is easily melted and the conductor can be easily restored to its original shape. Therefore, due to abnormal heat generation of the electronic component, the electronic component side of the conductor When the solder is melted, the conductor and the power supply path on the electronic component side are easily separated from each other, so that abnormal heat generation of the mounted electronic component can be reliably prevented.

In the invention of claim 5, the solder used for mounting the conductor has a lower melting point than the solder used for mounting the electronic component. As a result, when the electronic component generates abnormal heat, the solder on the electronic component side of the conductor is easily melted, so that when the solder melts, the conductor and the power supply path on the electronic component side are easily separated. Therefore, it is possible to reliably prevent abnormal heat generation of the mounted electronic component.

It is sectional drawing which shows schematicly about the circuit board which concerns on 1st Embodiment. It is explanatory drawing explaining the conductor before elastic deformation in 1st Embodiment, FIG. 2A is a plan view, and FIG. 2B is a side view. It is explanatory drawing explaining the manufacturing process which manufactures the circuit board which concerns on 1st Embodiment. It is explanatory drawing explaining the action of the conductor when abnormal heat generation occurs in the electronic component of FIG. It is explanatory drawing explaining the main part of the manufacturing method of the circuit board which concerns on 1st modification of 1st Embodiment. It is explanatory drawing explaining the action of the conductor when abnormal heat generation occurs in the electronic component in the 1st modification of 1st Embodiment. It is explanatory drawing explaining the main part of the manufacturing method of the circuit board which concerns on 2nd modification of 1st Embodiment. It is explanatory drawing explaining the action of the conductor when an abnormal heat generation occurs in an electronic component in the 2nd modification of 1st Embodiment. It is sectional drawing which shows schematicly about the circuit board which concerns on 2nd Embodiment. It is explanatory drawing explaining the conductor before elastic deformation in 2nd Embodiment, FIG. 10A is a plan view, and FIG. 10B is a side view. It is explanatory drawing explaining the manufacturing process which manufactures the circuit board which concerns on 2nd Embodiment. It is explanatory drawing explaining the action of the conductor when abnormal heat generation occurs in the electronic component of FIG. It is explanatory drawing explaining the main part of the manufacturing method of the circuit board which concerns on the modification of 2nd Embodiment. It is explanatory drawing explaining the action of the conductor when an abnormal heat generation occurs in an electronic component in the modified example of 2nd Embodiment.

[First Embodiment]
Hereinafter, a method for manufacturing a circuit board according to the first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view schematically showing a circuit board 10 according to the first embodiment.
The circuit board 10 according to the present embodiment is configured as a multilayer board that is a main part of, for example, an electronic control unit that controls in-vehicle devices such as seats, lamps, and engines mounted on a vehicle. .. The circuit board 10 is an electronic component 20 that generates heat during predetermined control such as a power MOSFET on the mounting surface of a multilayer printed wiring board 11 in which insulating layers and conductive layers made of epoxy resin or the like are alternately laminated. And connectors are mounted after undergoing reflow processing and the like.

The printed wiring board 11 is provided with a conductor 30 for protecting the electronic component 20 between the power supply paths of the electronic component 20. The conductor 30 is formed by deforming a thin strip-shaped (flat plate-shaped) conductive plate made of copper or phosphor bronze into a substantially M-shaped cross section as described later, and serves as an interval between power supply paths of the electronic component 20. , The electronic component 20 is provided between the power supply wirings (hereinafter, also referred to as the power supply path 50) joined by the solder 41. That is, the conductor 30 electrically connects the electronic component side wiring 51 and the anti-electronic component side wiring 52 that are electrically separated to form a part of the power supply path 50. The surface of the conductor 30 is subjected to oxidative corrosion prevention treatment by plating or the like.

Specifically, the conductor 30 is for solder joining provided at the top plate portion 31, the side plate portions 32a and 32b extending downward from both ends of the top plate portion 31, and the lower ends of the side plate portions 32a and 32b, respectively. 33a and 33b are provided. The conductor 30 is solder-bonded to the electronic component side wiring 51 at the joint portion 33a using solder 42a, and solder-bonded to the anti-electronic component side wiring 52 at the joint portion 33b using solder 42b. Then, as will be described later, in the top plate portion 31, the central portion 31a is pressed toward the mounting surface side and plastically deformed, and the connecting portion of the top plate portion 31 and the joint portion 33b is connected to the top plate portion 31 and the side plate portion 32a. The part is held in an elastically deformed state. That is, the conductor 30 is in a state in which restoration to the original shape before elastic deformation is suppressed by the solder 42a and the solder 42b.

Next, a method of manufacturing the circuit board 10 configured as described above will be described with reference to FIGS. 2 and 3. In the following description, for convenience, mounting of components different from the conductor 30 and the electronic component 20 on the printed wiring board 11 is omitted.
First, as shown in FIGS. 2A and 2B, a conductor 30 having a flat top plate portion 31 is prepared. Next, the conductor 30 and the electronic component 20 and the like are mounted (mounted) on the printed wiring board 11 to which the cream solder is applied at a predetermined position in advance by using the adsorption function of the automatic machine, and then heated in the reflow furnace. To do. As a result, as shown in FIG. 3A, the joint portion 33a is soldered to the electronic component side wiring 51 using the solder 42a, and the joint portion 33b is soldered to the anti-electronic component side wiring 52 using the solder 42b. By joining, the conductor 30 is solder-bonded between the power supply paths 50.

Subsequently, after the solders 42a and 42b are fixed and the solder bonding is completed after a lapse of a predetermined time, as shown in FIG. 3B, the top plate portion 31 of the conductor 30 is formed by using the predetermined jig 100. The central portion 31a of the above is pressed toward the mounting surface side. As a result, the circuit board 10 shown in FIG. 1 is completed, and the conductor 30 is plastically deformed by pressing the central portion 31a of the top plate portion 31 toward the mounting surface side, and the top plate portion 31 and the side plate portion 32a are connected. The portion and the connecting portion of the top plate portion 31 and the side plate portion 32b are each elastically deformed, and the restoring force corresponding to the elastic deformation is maintained.

Next, the action of the conductor 30 when abnormal heat generation occurs in the electronic component 20 in the circuit board 10 manufactured as described above will be described with reference to FIG.
When abnormal heat generation occurs in the electronic component 20, the abnormal heat generation is transmitted from the electronic component 20 to the solder 42a via the electronic component side wiring 51 of the power supply path 50, and the solder 42a is melted. As a result, the holding force of the solder 42a on the conductor 30 is released, and the conductor 30 tries to restore its original shape before elastic deformation. At that time, since the solder 42b is not melted, as shown in FIG. 4, the conductor 30 is connected to the top plate portion 31 and the side plate portion 32a so as to be restored to the original shape based on the solder 42b. The connecting portion of the plate portion 31 and the side plate portion 32b is deformed, and the joint portion 33a is separated from the electronic component side wiring 51. By separating the conductor 30 and the electronic component side wiring 51 in this way, the power supply to the electronic component 20 is stopped, so that abnormal heat generation of the mounted electronic component 20 is prevented.

As described above, in the method for manufacturing the circuit board 10 according to the present embodiment, the conductor 30 is solder-bonded between the power supply paths 50, and the conductor 30 is elastically deformed after the solder bonding is completed. The circuit board 10 is manufactured. As a result, when abnormal heat generation occurs in the electronic component 20, the solder 42a melts and the conductor 30 and the electronic component side wiring 51 are separated from each other, so that the power supply to the electronic component 20 is stopped. Therefore, the mounted electronic component It is possible to prevent 20 abnormal heat generation. In particular, since it is only necessary to elastically deform the conductor 30 using the jig 100 after the solder bonding is completed, there is no need for a manual process such as cutting a predetermined portion of the conductor 30, and it is automated. Can be easily dealt with. Therefore, it is possible to increase the productivity of the circuit board 10 while preventing abnormal heat generation of the mounted electronic component 20.

Further, after the solder bonding is completed, the center portion 31a (center portion side in the longitudinal direction) of the top plate portion 31 of the conductor 30 is pressed against the mounting surface side of the printed wiring board 11 to plastically deform the conductor 30. The connecting portion of the top plate portion 31 and the joint portion 33b and the connecting portion (end side in the longitudinal direction) of the top plate portion 31 and the side plate portion 32a are elastically deformed. In this way, by plastically deforming the central portion side in the longitudinal direction of the conductor 30 and elastically deforming the end side in the longitudinal direction, the end side in the longitudinal direction that was joined to the solder 42a at the time of solder melting moves and becomes conductive. Since the body 30 and the electronic component side wiring 51 are easily separated from each other, abnormal heat generation of the mounted electronic component 20 can be reliably prevented.

In particular, the conductor 30 is made of copper or phosphor bronze formed in a flat plate shape. As a result, since the conductor 30 has both springiness and solderability, the solder 42a is easily melted and the conductor 30 is easily restored to its original shape. Therefore, the solder 42a is generated by abnormal heat generation of the electronic component 20. Since the conductor 30 and the electronic component side wiring 51 are easily separated from each other when melting, it is possible to reliably prevent abnormal heat generation of the mounted electronic component 20.

The solder used for mounting the conductor 30 (at least the solder 42a) is configured to have the same characteristics as the solder 41 used for mounting the electronic component 20 and to have the same melting point, but is not limited to this. The melting point may be lower than that of the solder 41 used for mounting the component 20. In this case, when the electronic component 20 generates abnormal heat, the solder 42a is easily melted. Therefore, when the solder 42a is melted, the conductor 30 and the electronic component side wiring 51 are easily separated from each other. It is possible to reliably prevent abnormal heat generation of the electronic component 20.

FIG. 5 is an explanatory diagram illustrating a main part of a method for manufacturing a circuit board according to a first modification of the first embodiment, and FIG. 5 (A) shows a state of the conductor 30a before elastic deformation. FIG. 5B shows the state of the elastically deformed conductor 30a. FIG. 6 is an explanatory diagram illustrating the action of the conductor 30a when abnormal heat generation occurs in the electronic component 20 in the first modification of the first embodiment.
The conductor that heats and protects the electronic component 20 is not limited to being formed like the conductor 30 described above, but may be formed so as to elastically deform after solder bonding and return to the original shape when the solder melts. For example, as a first modification of the present embodiment, the conductor 30a shown in FIGS. 5A and 5B may be formed.

As shown in FIG. 5A, the conductor 30a abolishes the side plate portion 32b with respect to the above-mentioned conductor 30 and connects the top plate portion 31 and the joint portion 33b to these connecting portions before elastic deformation. In order to make it difficult to plastically deform (to facilitate elastic deformation), the top plate portion 31 and the side plate portion 32a are formed in a substantially U-shape in a side view so as to be connected in an acute angle. That is, in the conductor 30a, the portion of the conductor 30a that is solder-bonded to the solder 42b away from the electronic component 20 with respect to the power supply path 50 is more elastically deformed than the portion that is solder-bonded to the solder 42a on the electronic component side. Easily formed. Then, as shown in FIG. 5B, after soldering, the vicinity of the central portion of the top plate portion 31 is plastically deformed using a predetermined jig 101, and the connecting portion of the top plate portion 31 and the joint portion 33b and the top plate are formed. Each of the connecting portion of the portion 31 and the side plate portion 32a is elastically deformed, and the restoring force corresponding to the elastic deformation is held by the conductor 30a.

Even in this way, as shown in FIG. 6, when abnormal heat generation occurs in the electronic component 20, the solder 42a melts and the conductor 30a and the electronic component side wiring 51 are separated from each other to supply electric power to the electronic component 20. Since it is stopped, it is possible to prevent abnormal heat generation of the mounted electronic component 20. Then, since it is only necessary to elastically deform the conductor 30a after the solder bonding is completed, automation can be easily supported. In particular, since the joint portion 33b side of the top plate portion 31 close to the solder 42b, which is the reference at the time of restoration, is less likely to be plastically deformed (because it is easily elastically deformed), springiness that can be used as a restoration force can be reliably secured. That is, when the solder 42a on the electronic component side melts, the conductor 30a is solder-bonded to the solder 42a on the electronic component side due to deformation at a portion on the side where the solder 42a is solder-bonded away from the electronic component 20. Since the portion to be soldered is largely separated from the power supply path 50 on the electronic component side, abnormal heat generation of the mounted electronic component 20 can be prevented more reliably.

FIG. 7 is an explanatory diagram illustrating a main part of a method for manufacturing a circuit board according to a second modification of the first embodiment, and FIG. 7A shows a state of the conductor 30b before elastic deformation. FIG. 7B shows the state of the elastically deformed conductor 30b. FIG. 8 is an explanatory diagram illustrating the action of the conductor 30b when abnormal heat generation occurs in the electronic component 20 in the second modification of the first embodiment.
Further, the conductor that heats and protects the electronic component 20 may be formed as shown in FIGS. 7A and 7B as, for example, as a second modification of the present embodiment.

As shown in FIG. 7A, the conductor 30b has a side plate portion 32b with respect to the conductor 30 described above before the elastic deformation for the purpose of making it more difficult to plastically deform (make it easier to elastically deform). Instead, it is formed so as to have a connecting portion 32c that connects the top plate portion 31 and the joining portion 33b in an arc shape (R shape). That is, in the conductor 30b, the portion of the conductor 30b that is solder-bonded to the solder 42b away from the electronic component 20 with respect to the power supply path 50 is more elastically deformed than the portion that is solder-bonded to the solder 42a on the electronic component side. Easily formed. Then, as shown in FIG. 7B, after solder joining, the vicinity of the central portion of the top plate portion 31 is plastically deformed using a predetermined jig 102, and the connecting portion 32c is connected to the top plate portion 31 and the side plate portion 32a. Each portion is elastically deformed, and the restoring force corresponding to the elastic deformation is held by the conductor 30b.

Even in this way, as shown in FIG. 8, when abnormal heat generation occurs in the electronic component 20, the solder 42a melts and the conductor 30b and the electronic component side wiring 51 are separated from each other to supply electric power to the electronic component 20. Since it is stopped, it is possible to prevent abnormal heat generation of the mounted electronic component 20. Then, since it is only necessary to elastically deform the conductor 30b after the solder bonding is completed, automation can be easily supported. In particular, since the connecting portion 32c close to the solder 42b, which is the reference at the time of restoration, is difficult to be plastically deformed (because it is easily elastically deformed), the springiness that can be used as the restoration force can be surely secured. That is, when the solder 42a on the electronic component side melts, the conductor 30b is solder-bonded to the solder 42a on the electronic component side due to deformation at a portion on the side where the solder 42a is solder-bonded away from the electronic component 20. Since the portion to be soldered is largely separated from the power supply path 50 on the electronic component side, abnormal heat generation of the mounted electronic component 20 can be prevented more reliably.

[Second Embodiment]
Next, the method of manufacturing the circuit board according to the second embodiment of the present invention will be described with reference to FIGS. 9 to 12.
In the circuit board manufacturing method according to the second embodiment, the point that the conductor provided between the power supply paths of the electronic components is elastically deformed before the solder bonding is the main point as the circuit board manufacturing method according to the first embodiment. Different to. Therefore, substantially the same components as the circuit board of the first embodiment described above are designated by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 9, in the circuit board 10a according to the present embodiment, the conductor 60 is adopted instead of the conductor 30 described above. The conductor 60 is formed by deforming a thin strip-shaped (flat plate-shaped) conductive plate made of copper or phosphor bronze as described later, and is composed of a substantially semi-cylindrical connecting portion 61 and the connecting portion 61. Joint portions 62a and 62b for solder bonding, which are connected to both lower ends, respectively, are provided. Similar to the conductor 30, the surface of the conductor 60 is subjected to oxidative corrosion prevention treatment by plating or the like.

The conductor 60 is solder-bonded to the electronic component side wiring 51 using solder 42a at the joint portion 62a, and solder-bonded to the anti-electronic component side wiring 52 using solder 42b at the joint portion 62b. Then, the conductor 60 is held in an elastically deformed state as described later. That is, the conductor 60 is in a state in which restoration to the original shape before elastic deformation is suppressed by the solder 42a and the solder 42b, similarly to the conductor 30 described above.

Next, a method of manufacturing the circuit board 10a configured as described above will be described with reference to FIGS. 10 and 11. In the following description, for convenience, mounting of components different from the conductor 60 and the electronic component 20 on the printed wiring board 11 is omitted.
First, as shown in FIGS. 10A and 10B, the width W2 of the semi-cylindrical connecting portion 61 is the width W1 at the time of solder joining (see FIG. 9) in a state where no external urging force is applied. A conductor 60 is prepared which is slightly longer than the above and is in a state where the plane including the lower surface of the joint portion 62a and the plane including the lower surface of the joint portion 62b intersect at a predetermined angle α.

Next, as shown in FIG. 11A, the resin cap 110 is covered from the connecting portion 61 side. The cap 110 functions as an urging member for urging the conductor 60 from the outside at the connecting portion 61 to elastically deform it, and corresponds to the longitudinal direction of the connecting portion 61 (left-right direction in FIG. 11). It is formed so that the distance between the inner wall surfaces in the direction is substantially equal to the width W1. Therefore, the width of the connecting portion 61 of the conductor 60 elastically deformed by covering with the cap 110 is W1. At that time, the joint portion 62a and the joint portion 62b are pressed by the lower end portion of the cap 110 with the upper surface of the connecting portion 61 in contact with the inner surface of the cap 110, and the flat surface including the lower surface of the joint portion 62a and the lower surface of the joint portion 62b. The predetermined angle α is set so that the plane including the above is substantially the same plane. The cap 110 is not limited to being made of resin, and may be formed of a member capable of elastically deforming the attached conductor 60.

Subsequently, the conductor 60 and the electronic component 20 and the like are elastically deformed by covering the printed wiring board 11 to which the cream solder is applied at a predetermined position in advance by covering the cap 110 with the suction function of the automatic machine. After mounting, it is heated in a reflow oven. As a result, as shown in FIG. 11B, the joint portion 62a is soldered to the electronic component side wiring 51 using the solder 42a, and the joint portion 62b is soldered to the anti-electronic component side wiring 52 using the solder 42b. By joining, the conductor 60 is solder-bonded between the power supply paths 50.

Subsequently, after the solders 42a and 42b are fixed and the solder bonding is completed after a lapse of a predetermined time, the cap 110 is removed from the conductor 60 as shown in FIG. 11C. As a result, the circuit board 10a shown in FIG. 9 is completed, and in the conductor 60, the connecting portion 61 is narrowed by the width W1 in the longitudinal direction thereof, and the angle between the connecting portion 61 and the joining portion 62a and the joining portion 61 are joined. It is elastically deformed and held so that the angle with the portion 62b becomes large.

Next, the action of the conductor 30 when abnormal heat generation occurs in the electronic component 20 in the circuit board 10a manufactured as described above will be described with reference to FIG.
When the solder 42a melts in response to the abnormal heat generation of the electronic component 20, the holding force of the solder 42a on the conductor 60 is released, and the conductor 60 tries to restore its original shape before elastic deformation. At that time, since the solder 42b is not melted, as shown in FIG. 12, the conductor 60 is restored to its original shape based on the solder 42b, and the joint portion 62a is separated from the electronic component side wiring 51. It becomes. By separating the conductor 60 and the electronic component side wiring 51 in this way, the power supply to the electronic component 20 is stopped, so that abnormal heat generation of the mounted electronic component 20 is prevented.

As described above, in the method for manufacturing the circuit board 10a according to the present embodiment, the conductor 60 elastically deformed by using the cap 110 is solder-bonded between the power supply paths 50, and the conductor is conductive after the solder bonding is completed. The circuit board 10a is manufactured by removing the cap 110 from the body 60. Even in this way, it is possible to prevent abnormal heat generation of the mounted electronic component 20 as in the first embodiment. In particular, since it is only necessary to remove the cap 110 after solder joining, there is no need for a work process that requires manual work such as cutting a predetermined portion of the conductor, and automation can be easily supported. Therefore, it is possible to increase the productivity of the circuit board 10a while preventing abnormal heat generation of the mounted electronic component 20.

FIG. 13 is an explanatory diagram illustrating a main part of a method for manufacturing a circuit board according to a modification of the second embodiment, and FIG. 13A shows a state of the conductor 60a before elastic deformation. FIG. 13B shows a state in which the conductor 60a elastically deformed by covering the cap 110a is mounted on the printed wiring board 11, and FIG. 13C shows the cap 110a removed from the conductor 60a after solder bonding. Indicates the state. FIG. 14 is an explanatory diagram illustrating the action of the conductor 60a when abnormal heat generation occurs in the electronic component 20 in the modified example of the second embodiment.
The conductor that heats and protects the electronic component 20 is not limited to being formed like the conductor 60 described above, but is formed so as to be solder-bonded in an elastically deformed state using an urging member such as a cap 110. For example, the conductor 60a shown in FIG. 13 may be formed.

As shown in FIG. 13A, the conductor 60a has a top plate portion 63 having a central portion recessed toward the mounting surface and an acute angle at the upper end with respect to the top plate portion 63, in addition to the joint portions 62a and 62b described above. It is formed so as to include a side plate portion 64 that is connected in a shape and is connected to the joint portion 62a at the lower end, and a connecting portion 65 that connects the top plate portion 63 and the joint portion 62b in an arc shape (R shape). In particular, the conductor 60a is formed so that the width W4, which is the distance between the outer surface of the side plate portion 64 and the outer surface of the connecting portion 65, is slightly longer than the width W3 of the cap 110a that functions as an urging member. (See FIG. 13 (A)).

As shown in FIG. 13B, the conductor 60a formed in this way is mounted on the printed wiring board 11 together with the electronic component 20 and the like in a state of being elastically deformed by covering with the cap 110a. At this time, the conductor 60a is urged so that the connecting portion 65 and the side plate portion 64 are brought close to each other, and the conductor 60a is elastically deformed so that the vicinity of the central portion of the top plate portion 63 is further recessed toward the mounting surface side. Then, after the solders 42a and 42b are fixed and the solder bonding is completed after a lapse of a predetermined time, the circuit board 10a is completed by removing the cap 110a from the conductor 60a as shown in FIG. 13C. ..

Even in this way, as shown in FIG. 14, when abnormal heat generation occurs in the electronic component 20, the solder 42a melts and the conductor 60a and the electronic component side wiring 51 are separated from each other in the same manner as the conductor 30b, and the electric power is generated. Since the power supply to the component 20 is stopped, abnormal heat generation of the mounted electronic component 20 can be prevented. Since it is only necessary to remove the cap 110a after solder joining, automation can be easily supported.

The present invention is not limited to the above embodiments and modifications, and may be embodied as follows.
(1) The present invention is not limited to being applied to a method for manufacturing a circuit board for an in-vehicle device, but is also applied to a method for manufacturing a circuit board having other functions, such as manufacturing a circuit board for a sensor. May be good.

(2) In the first embodiment, the central portion 31a of the top plate portion 31 is pressed toward the mounting surface side in order to easily elastically deform the conductor 30 by the jig 100, but the present invention is not limited to this. If the holding force on the conductor 30 is released by melting the solder 42a and the conductor 30 is restored to its original shape before elastic deformation and is separated from the electronic component side wiring 51, the side plate portion 32b and the like are conductive. Other parts of the body 30 may be elastically deformed. The same applies to the conductors 30a and 30b described above.

(3) In the second embodiment, the conductor 60 is elastically deformed in an obliquely upward direction so that the joint portion 62a is separated from the mounting surface after the solder 42a is melted, so that the conductor 60 and the electronic component side wiring 51 are surely connected. The predetermined angle α is set so as to be separated, but the present invention is not limited to this. For example, if the joint portion 62a that has moved toward the electronic component 20 along the mounting surface according to the elastic deformation of the conductor 60 after the solder 42a is melted and the electronic component side wiring 51 are separated from each other. The predetermined angle α may be set to be substantially 0 °. The same applies to the conductor 60a described above.

(4) In the second embodiment, the conductor 60 is elastically deformed by covering the conductor 60 with the cap 110, but the present invention is not limited to this, and the cap 110 is elastically deformed while the conductor 60 is elastically deformed. You may cover it. The same applies to the conductor 60a described above.

(5) In the second embodiment and the modified example, the conductors 60 and 60a are put into an elastically deformed state by covering them with caps 110 and 110a, but the present invention is not limited to this, and for example, urging is carried out in an annular shape from the outer peripheral side. The conductors 60 and 60a may be brought into an elastically deformed state by using a force member or the like. Further, as the conductor, as long as it has a shape that can be mounted in a state of being urged by the urging member, for example, a spring material having a shape such as a known coil spring may be adopted.

10, 10a ... Circuit board 11 ... Printed wiring board 20 ... Electronic components 30, 30a, 30b, 60, 60a ... Conductors 31 ... Top plate parts 41a, 41b ... Solder 50 ... Power supply path 51 ... Electronic component side wiring 52 ... Anti-electronic component side wiring 110, 110a ... Cap (urgency member)

Claims (5)

A method for manufacturing a circuit board in which a conductor for protecting an electronic component is provided between power supply paths of the electronic component mounted on a printed wiring board.
A step of soldering the conductor between the power supply paths,
A step of elastically deforming the conductor after the solder bonding is completed,
A method for manufacturing a circuit board, which comprises. After the solder bonding is completed, the central portion side in the longitudinal direction of the conductor is pressed against the mounting surface side of the printed wiring board to be plastically deformed, thereby elastically deforming the end side in the longitudinal direction of the conductor. The method for manufacturing a circuit board according to claim 1, wherein the circuit board is manufactured. A method for manufacturing a circuit board in which a conductor for protecting an electronic component is provided between power supply paths of the electronic component mounted on a printed wiring board.
A step of elastically deforming the conductor using an urging member,
A step of solder-bonding the elastically deformed conductor between the power supply paths, and
A step of removing the urging member from the conductor after the solder bonding is completed,
With
In the conductor, a portion of the power supply path on the side solder-bonded to the solder away from the electronic component is more easily elastically deformed than the portion solder-bonded to the solder on the electronic component side. It is a manufacturing method of a circuit board according to claim Rukoto. The method for manufacturing a circuit board according to any one of claims 1 to 3, wherein the conductor is made of copper or phosphor bronze formed in a flat plate shape. The method for manufacturing a circuit board according to any one of claims 1 to 4, wherein the solder used for mounting the conductor has a melting point lower than that of the solder used for mounting the electronic component.

Images