JP7203651B2 - connection terminal, electronic device - Google Patents

Description

The present invention relates to a connection terminal for electrically connecting circuit boards facing each other at a predetermined interval, and an electronic device including the connection terminal and the circuit board.

2. Description of the Related Art In an electronic device having a plurality of circuit boards, connection terminals are used to electrically connect the circuit boards facing each other at a predetermined interval. Each end of the connection terminal is provided with a connection portion that is electrically connected to the circuit board by soldering. The connection portion includes an insertion mount type connection portion and a surface mount type connection portion.

For example, in Japanese Unexamined Patent Application Publication No. 2002-100001, an insertion mounting type connecting portion is provided at the upper end portion of the connecting terminal, and a surface mounting type connecting portion is provided at the lower end portion. Further, in Patent Documents 2 and 3, insertion mounting type connection portions are provided at the upper and lower ends of the connection terminals.

The surface-mounted connection part is mounted on pads provided on the surface of the circuit board and connected to the pads by soldering. The insertion mounting type connection part is connected by soldering to a land provided on the circuit board so as to surround the through hole while being inserted into the through hole provided on the circuit board.

In order to facilitate insertion into a small-diameter through-hole provided in a circuit board, the insertion mounting type connecting portion is formed over a predetermined length from one end of the connecting terminal with a smaller diameter than the other portions. There is (Patent Document 1).

Due to external forces such as temperature changes and vibrations, stress may be applied to the connection portions between the connection terminals and the circuit board. In order to absorb the stress, a curved portion is sometimes provided in the central portion of the connection terminal (Patent Documents 1 to 3).

JP-A-2007-242473 Japanese Utility Model Laid-Open No. 52-142646 JP-A-8-236178

FIG. 6 is a cross-sectional view of a connection portion between a conventional connection terminal 50 and a circuit board 60. As shown in FIG. The circuit board 60 is provided with a through hole 61 that is a through hole. Lands 62 are provided around the through holes 61 on the front and back surfaces of the circuit board 60 . An insertion mounting type connection portion 51 is formed over a predetermined length from one end of the connection terminal 50 and has a smaller diameter than the other portions. The insertion mounting type connecting portion 51 is connected to the through hole 61 and the land 62 by solder 70 while being inserted into the through hole 61 of the circuit board 60 . A fillet of solder 70 is formed from the insertion mounting type connection portion 51 to the outer peripheral edge of the land 62 on the front surface and the rear surface of the circuit board 60 .

The operation of connecting the insertion mounting type connection portion 51 of the connection terminal 50 to the through hole 61 of the circuit board 60 or the like is performed by an automatic machine or manually. At that time, the amount of solder 70 may vary. When the amount of solder 70 increases, the fillet height of the solder 70 from the circuit board 60 increases, and the portion 52 of the connection terminal 50 having a larger diameter than the insertion mounting type connection portion 51 and the circuit board 60 are separated from each other. A sharply undulating V-shaped constriction 80 is formed between them. In this state, when an external force such as a temperature change or vibration is applied to the circuit board 60, the shear stress τ generated by the external force is concentrated on one section X of the connection terminal 50 corresponding to the portion where the constriction 80 has the smallest diameter. , the connection terminal 50 may be broken at the cross section X.

An object of the present invention is to prevent a connection terminal from being broken by an external force.

A connection terminal of the present invention is a terminal for electrically connecting circuit boards facing each other at a predetermined interval, and includes an insertion mounting type connection portion, a large diameter portion, and a small diameter continuous portion . The insertion mounting type connection part is formed with a small diameter over a predetermined length from the end of the connection terminal, and is connected to the circuit board by soldering while being inserted into a through hole provided in the circuit board. be. The large diameter portion has a larger diameter than the insertion mount connection portion. The small-diameter continuous portion is formed between the insertion mounting type connecting portion and the large diameter portion so as to have the same diameter as the insertion mounting type connecting portion and to be continuous with the insertion mounting type connecting portion. The insertion mounting type connection part has a buried part buried in the through hole of the circuit board, a front end side projecting part projecting on the opposite side of the through hole from the large diameter part, and a projecting part on the large diameter side of the through hole. It is composed of a root side protruding part that The small-diameter continuous portion continues for a predetermined length from the root-side projecting portion. The insertion mounting type connecting portion is connected by soldering to a land provided around the through-hole on the surface of the circuit board. The protruding length of the base-side protruding portion of the insertion mounting type connection portion from the through hole and the length of the small diameter continuous portion are each equal to or greater than the diameter from the insertion mounting type connection portion to the outer peripheral edge of the land.

An electronic device of the present invention includes the connection terminal and a plurality of circuit boards facing each other at a predetermined interval and electrically connected by the connection terminal.

According to the above configuration, the small-diameter continuous portion having the same diameter as the insertion mounting type connecting portion is formed between the large diameter portion of the connection terminal and the insertion mounting type connecting portion so as to be continuous with the insertion mounting type connecting portion. there is As a result, even if a large amount of solder is applied to the insertion mounting connection inserted into the through-hole of the circuit board, the solder remains within the range of the insertion mounting connection and the small-diameter continuous portion, and is not applied to the large-diameter portion. will not reach. As a result, sharply undulating V-shaped constrictions do not occur between the large-diameter portions of the connection terminals and the circuit board. Therefore, even if external forces such as temperature changes and vibrations are applied to the circuit board of the electronic device, the shear stress caused by these external forces will not concentrate on one section of the connection terminal between the large diameter portion and the solder. Since the stress is dispersed in the small-diameter continuous portion of the connection terminal, it is possible to prevent the connection terminal from breaking due to an external force.

Moreover, in the present invention, a tapered portion formed such that the diameter gradually decreases from the large-diameter portion to the small-diameter continuous portion of the connection terminal may be further provided. The angle of the tapered portion with respect to the peripheral surface of the small-diameter continuous portion is preferably 135° or more.

Further, in the present invention, the large-diameter portion of the connection terminal may have a curved portion curved in an S-shape.

Further, in the present invention, the insertion mounting type connection portion may be formed at the upper end portion of the connection terminal, and the small-diameter continuous portion may be formed so as to continue below the insertion mounting type connection portion.

Furthermore, in the present invention, an insertion mounting type connecting portion connected by soldering to a land provided on the surface of one of the circuit boards is formed at one end of the connecting terminal, and the other end of the connecting terminal Alternatively, a surface-mounted connection portion may be formed to be connected by soldering to a pad provided on the surface of the other circuit board.

According to the present invention, it is possible to prevent breakage of the connection terminal due to external force.

1 is a perspective view of essential parts of an electronic device according to an embodiment of the present invention; FIG. 2 is a perspective view of the connection terminal of FIG. 1; FIG. 2 is a side view of connection terminals and circuit boards in FIG. 1; FIG. 2 is a cross-sectional view showing an example of a connection state between the connection terminal of FIG. 1 and one circuit board; FIG. FIG. 4 is a cross-sectional view showing another example of a connection state between the connection terminal of FIG. 1 and one circuit board; FIG. 3 is a cross-sectional view of a connection portion between a conventional connection terminal and a circuit board;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each figure, the same reference numerals are given to the same or corresponding parts.

FIG. 1 is a perspective view of a main part of an electronic device 10 according to an embodiment.

The electronic device 10 is composed of, for example, a vehicle-mounted DC-DC converter. The electronic device 10 is installed near a travel drive source such as a vehicle engine. The electronic device 10 includes circuit boards 1 and 2, connection terminals 3, and the like. Each circuit board 1, 2 consists of a printed circuit board. Electronic parts constituting a DC-DC converter are mounted on each of the circuit boards 1 and 2 to form an electric circuit (not shown).

Spacers 4 are provided between the corners 1 k of the circuit board 1 and the corners 2 k of the circuit board 2 . The circuit board 1 is fixed to the upper surface of each spacer 4 with screws 5 . The circuit board 2 is fixed to the lower surface of each spacer 4 with screws (not shown). Thereby, the circuit board 1 and the circuit board 2 are arranged so as to face each other at a predetermined interval.

The connection terminal 3 is made of a conductor. The connection terminals 3 electrically connect the circuit boards 1 and 2 together. Although the circuit boards 1 and 2 are electrically connected by two connection terminals 3 in FIG. 1, the number of connection terminals 3 may be one or three or more.

FIG. 2 is a perspective view of the connection terminal 3. FIG. FIG. 3 is a side view of the connection terminals 3 and the circuit boards 1 and 2. As shown in FIG. FIG. 4 is a cross-sectional view showing an example of a connection state between the connection terminal 3 and one circuit board 1. As shown in FIG. FIG. 5 is a cross-sectional view showing another example of the connection state between the connection terminal 3 and one circuit board 1. As shown in FIG.

As shown in FIG. 2, the connection terminal 3 is formed by punching out a conductive sheet metal and then bending the punched sheet.

An insertion mounting type connection portion 3a is formed at the upper end portion of the connection terminal 3. As shown in FIG. Specifically, the insertion mounting type connection portion 3 a is formed over a predetermined length from the upper end of the connection terminal 3 .

The diameter of the insertion mounting type connecting portion 3 a is smaller than the diameter of the large diameter portion 3 d extending from the center to the lower end of the connecting terminal 3 . Specifically, since the plate thickness of the connection terminal 3 is the same over the entire length of the connection terminal 3, as shown in FIGS. is getting smaller.

A small-diameter continuous portion 3b and a tapered portion 3c are formed between the large-diameter portion 3d of the connection terminal 3 and the insertion mounting type connection portion 3a. The small-diameter continuous portion 3b has the same diameter (same width) as that of the insertion mounting type connection portion 3a, and is formed continuously with the connection portion 3a. The tapered portion 3c is formed such that the diameter (width) gradually decreases from the large diameter portion 3d to the small diameter continuous portion 3b.

As shown in FIG. 2, the large-diameter portion 3d of the connection terminal 3 is provided with a curved portion 3e that is curved in an S shape. A surface mount type connection portion 3f is formed at the lower end portion of the connection terminal 3. As shown in FIG. Specifically, the surface-mounted connection portion 3f is formed by horizontally bending a portion extending from the lower end of the connection terminal 3 to a predetermined length. The surface-mounted connection portion 3f constitutes a part of the curved portion 3e.

As shown in FIGS. 1 and 3, the surface-mounted connection portion 3f is placed on the pad 2p provided on the upper surface (front surface) of the circuit board 2, and is connected to the pad 2p with solder 6. It is Each step of placing and connecting the surface-mounted connection portion 3f is performed by an automatic machine or manually. The pads 2p are electrically connected to an electric circuit formed on the circuit board 2 (not shown).

In order to increase the bonding area between the surface mount type connection portion 3f and the solder 6, a through hole 3g is formed in the surface mount type connection portion 3f as shown in FIG. The solder 6 enters this through hole 3g.

As shown in FIGS. 4 and 5, the circuit board 1 is provided with through holes 1h. The through hole 1h is composed of a hole (reference numeral omitted) formed in the circuit board 1 and a conductor (reference numeral omitted) provided on the inner peripheral surface of the hole and the open end. Lands 1r are provided around the through holes 1h on the upper surface (front surface) and the lower surface (back surface facing the circuit board 2) of the circuit board 1. As shown in FIG. The through hole 1h is an example of a "through hole" in the present invention.

The insertion mounting type connection portion 3a of the connection terminal 3 is inserted into the through hole 1h provided in the circuit board 1, and the solder 7 is applied to the through hole 1h and the land 1r provided around the through hole 1h. are electrically connected by Each step of inserting and connecting the insertion mounting type connecting portion 3a is performed by an automatic machine or manually. The through holes 1h and lands 1r are electrically connected to an electric circuit formed on the circuit board 1 (not shown).

The insertion mounting type connection portion 3a includes a buried portion 3a2 buried in the through hole _1h , a tip side projecting portion 3a1 projecting on the opposite _side of the through hole 1h from the large diameter portion 3d, and a It is composed of a root side projecting portion _3a3 projecting toward the large diameter portion 3d.

Fillets of solder 7 are formed on the upper and lower surfaces of the circuit board 1 from the protruding portions 3a ₁ and 3a ₃ of the insertion mounting type connection portion 3a to the outer peripheral edge of the land 1r. Due to the gravity of the solder 7 , the fillet of the solder 7 formed on the lower surface of the circuit board 1 is higher than the fillet of the solder 7 formed on the upper surface of the circuit board 1 .

The small-diameter continuous portion 3b continues downward for a predetermined length from the root _- side projecting portion 3a3 of the insertion mounting type connecting portion 3a. The protruding length L1 of the root side protruding portion _3a3 from the through hole 1h is set to be equal to or larger than the diameter D from the insertion mounting type connecting portion 3a to the outer peripheral edge of the land 1r (L1≧D). The length L2 of the small-diameter continuous portion 3b is also set to be equal to or larger than the diameter D from the insertion mounting type connection portion 3a to the outer peripheral edge of the land 1r (L2≧D).

As described above, the process of connecting the insertion mounting type connection portion 3a to the through hole 1h and the land 1r with the solder 7 is performed by an automatic machine or by hand, so the amount of the solder 7 may vary.

When the amount of solder 7 is small, as shown in FIG. 4, a fillet of solder 7 formed on the bottom surface of circuit board 1 is formed within the range of base-side projecting portion _3a3 of insertion mounting type connection portion 3a.

On the other hand, when the amount of solder ₇ is large, as shown in FIG. It is formed so as to extend partially.

However, even if the amount of the solder 7 varies, the fillet of the solder 7 generated on the lower surface of the circuit board 1 reaches the tapered portion 3c and the large diameter portion 3d, which are larger in diameter than the insertion mounting type connection portion 3a and the small diameter continuous portion 3b. never do. As a result, a gently undulating constriction 8 is formed between the large-diameter portion 3d of the connection terminal 3 and the circuit board 1, but a sharply undulating V-shaped constriction 80 as in the prior art shown in FIG. ceases to occur.

Moreover, the angle θ of the tapered portion 3c with respect to the peripheral surface of the small-diameter continuous portion 3b is set to 135° or more (θ≧135°). That is, the angle of the tapered portion 3c with respect to a cross section perpendicular to the longitudinal direction of the connection terminal 3 (vertical direction in FIGS. 3 to 5) (horizontal direction in FIGS. 3 to 5) is 45° or more. As a result, the diameter (width) of the connection terminal 3 gradually changes at the tapered portion 3c, so that the undulation of the constriction 8 between the large diameter portion 3d and the circuit board 1 becomes more gentle.

As described above, since the electronic device 10 is installed in the vicinity of the drive source of the vehicle, the electronic device 10 receives large vibrations and impacts generated by the drive source. Thermal shock due to ambient temperature changes is also transmitted to the electronic device 10 .

When an external force such as vibration or impact is applied to the circuit boards 1 and 2 of the electronic device 10 , the circuit boards 1 and 2 sway, and stress generated by the external force is applied to the connection terminals 3 . Among the stresses, the shearing stress τ generated in the horizontal direction as shown in FIGS. Further, as shown in FIG. 3, the stress σ generated in the vertical direction is absorbed by the curved portion 3e of the connection terminal 3. As shown in FIG. Therefore, it is possible to prevent the connection terminal 3 itself from being broken by an external force, and the connection portions (solder 7) between the connection terminal 3 and the circuit boards 1 and 2 from being damaged.

According to the above embodiment, between the large diameter portion 3d of the connection terminal 3 and the insertion mount type connection portion 3a, the small diameter continuous portion 3b having the same diameter as the insertion mount type connection portion 3a is continuous with the connection portion 3a. is formed as As a result, even if a large amount of solder 7 is used to connect the insertion mounting type connection portion 3a inserted into the through hole 1h of the circuit board 1 to the land 1r, the solder 7 on the lower surface side of the circuit board 1 is sufficient for the insertion mounting type connection. It remains within the range of the portion 3a and the small-diameter continuous portion 3b and does not reach the tapered portion 3c and the large-diameter portion 3d. Moreover, even if more solder 7 accumulates on the lower surface than on the upper surface of the circuit board 1 due to gravity, the solder 7 does not reach the tapered portion 3c or the large diameter portion 3d. As a result, a sharply undulating V-shaped constriction as shown in FIG. Therefore, even if external forces such as temperature changes and vibrations are applied to the circuit boards 1 and 2 of the electronic device 10, shear stress Don't focus on one section. Since the stress is dispersed at the small-diameter continuous portion 3b of the connection terminal 3, it is possible to prevent the connection terminal 3 from breaking due to an external force.

Further, in the above embodiment, the small-diameter continuous portion 3b of the connection terminal ₃ continues for a predetermined length from the root-side projecting portion 3a3 of the insertion mounting type connection portion 3a projecting downward from the through hole 1h. Therefore, the solder 7 that connects the insertion mounting type connecting portion 3a to the circuit board 1 reaches the portion (the tapered portion 3c and the large diameter portion 3d) having a larger diameter than the insertion mounting type connecting portion 3a and the small diameter continuous portion 3b. You can definitely stop it from happening. Further, the undulation of the constriction 8 generated between the large-diameter portion 3d of the connection terminal 3 and the circuit board 1 can be further moderated. As a result, the shear stress τ caused by the external force can be more dispersed in the small-diameter continuous portion 3b of the connection terminal 3, and breakage of the connection terminal 3 can be prevented more effectively.

Further, in the above embodiment, the length L1 of projection of the root side projecting portion _3a3 projecting from the through hole 1h and the length L2 of the small-diameter continuous portion 3b are different from the insertion mounting type connecting portion 3a to the through hole 1h. It is equal to or larger than the diameter D to the outer peripheral edge of the surrounding land 1r. For this reason, the fillets of the solder 7 on the lower surface side of the circuit board 1 are formed so as to be separated from the large-diameter portions 3d of the connection terminals 3 as much as possible so that they are formed between the large-diameter portions 3d of the connection terminals 3 and the circuit board 1 . The undulations of the constriction 8 can be made more gentle.

Further, in the above embodiment, the angle θ of the tapered portion 3c with respect to the peripheral surface of the small-diameter continuous portion 3b of the connection terminal 3 is 135° or more. Therefore, the undulation of the constriction 8 between the large-diameter portion 3d of the connection terminal 3 and the circuit board 1 can be further moderated.

Since the undulations of the constriction 8 are moderated as described above, the shear stress τ generated by an external force is less likely to concentrate on one section of the connection terminal 3 crossing the constriction 8 from side to side. In particular, it becomes difficult for the shear stress τ generated by the external force to concentrate on one section passing through the boundary between the small-diameter continuous portion 3b and the tapered portion 3c. Therefore, it is possible to prevent the connection terminal 3 from breaking at those cross-sectional portions.

Furthermore, in the above embodiment, the large-diameter portion 3d of the connection terminal 3 is formed with the S-shaped curved portion 3e. Therefore, the stress σ generated in the connection terminal 3 by an external force can be absorbed by the curved portion 3e. Further, it is possible to prevent the connection terminal 3 from being broken by an external force in the vicinity of the insertion mounting type connection portion 3a and the connection portion between the insertion mounting type connection portion 3a and the circuit board 1 from being damaged. In addition, it is possible to prevent damage to the connecting portion between the surface mount type connecting portion 3f and the circuit board 2. FIG.

The present invention can adopt various embodiments other than those described above.

For example, in the above embodiment, an example in which the insertion mounting type connection portion 3a is provided at one end of the connection terminal 3 has been shown, but the present invention is not limited to this. The other end of the connection terminal 3 may also be provided with an insertion mount type connection portion instead of the surface mount side connection portion 3f.

Moreover, in the above-described embodiment, an example in which the tapered portion 3c is provided between the small-diameter continuous portion 3b and the large-diameter portion 3d of the connection terminal 3 is shown, but the present invention is not limited to this. Instead of the tapered portion 3c, for example, a stepped portion whose diameter changes discontinuously may be provided between the small-diameter continuous portion 3b and the large-diameter portion 3d.

Further, in the above embodiment, an example in which the large-diameter portion 3d of the connection terminal 3 is provided with the S-shaped curved portion 3e is shown, but the present invention is not limited to this. In addition to this, the large-diameter portion 3d of the connection terminal 3 may be provided with a curved portion curved in another shape such as a U-shape or a spiral shape.

Further, in the above embodiment, an example in which the connection terminal 3 is formed by processing sheet metal has been shown, but the present invention is not limited to this. Alternatively, the connection terminal 3 may be formed by processing a metal wire, for example.

Furthermore, in the above embodiments, the present invention is applied to the electronic device 10, which is an in-vehicle DC-DC converter installed near the driving source of the vehicle, and the connection terminals 3 provided in the electronic device 10. Although examples have been given, the present invention can also be applied to other in-vehicle electronic devices, non-vehicle electronic devices, and connection terminals provided therewith.

1, 2 circuit board 1h through hole (through hole)
1r land 2 pad 3 connection terminal 3a insertion mount type connection portion 3a ₁ tip side projecting portion 3a ₂ embedded portion 3a ₃ root side projecting portion 3b small diameter continuous portion 3c tapered portion 3d large diameter portion 3e curved portion 3f surface mount type connection portion 6 , 7 Solder 10 Electronic device D Diameter from insertion mounting type connection part to outer peripheral edge of land L1 Projection length of root side projecting part L2 Length of small diameter continuous part θ Angle of taper part

Claims (6)

A connection terminal for electrically connecting circuit boards facing each other at a predetermined interval,
An insertion mounting type connection in which the connection terminal is formed with a small diameter over a predetermined length from the end of the connection terminal, and is connected to the circuit board by soldering while being inserted into a through hole provided in the circuit board. Department and
a large-diameter portion having a diameter larger than that of the insertion mounting type connection portion ;
a small-diameter continuous portion having the same diameter as the insertion-mounting type connecting portion and formed so as to be continuous with the insertion-mounting type connecting portion between the insertion-mounting type connecting portion and the large-diameter portion. at the terminal ,
The insertion mounting type connecting portion includes a buried portion buried in the through-hole, a tip-side protruding portion protruding on the opposite side of the through-hole from the large-diameter portion, and the large-diameter portion with respect to the through-hole. and a root side protruding portion that protrudes to the side,
The small-diameter continuous portion continues for a predetermined length from the root-side projecting portion,
The insertion mounting type connecting portion is connected by soldering to a land provided around the through hole on the surface of the circuit board,
A connection characterized in that the projection length of the root-side projecting portion from the through hole and the length of the small-diameter continuous portion are equal to or greater than a diameter from the insertion mounting type connection portion to the outer peripheral edge of the land. terminal. In the connection terminal according to claim 1 ,
further comprising a tapered portion formed such that the diameter gradually decreases from the large diameter portion to the small diameter continuous portion;
The connecting terminal, wherein the angle of the tapered portion with respect to the peripheral surface of the small-diameter continuous portion is 135° or more. In the connection terminal according to claim 1 or claim 2 ,
The connecting terminal, wherein the large-diameter portion has a curved portion curved in an S-shape. In the connection terminal according to any one of claims 1 to 3 ,
The insertion mounting type connection part is formed on the upper end of the connection terminal,
The connecting terminal, wherein the small-diameter continuous portion is formed so as to continue below the insertion mounting type connecting portion. In the connection terminal according to any one of claims 1 to 4 ,
one end of the connection terminal is formed with the insertion mounting type connection portion connected by soldering to a land provided on the surface of one of the circuit boards;
A connection terminal characterized in that a surface-mounted connection part connected by soldering to a pad provided on the surface of the other circuit board is formed at the other end of the connection terminal. a connection terminal according to any one of claims 1 to 5 ;
An electronic device comprising: a plurality of circuit boards facing each other at a predetermined interval and electrically connected by the connection terminals.

Images