阅读说明：本技术 连接端子和电子装置 (Connection terminal and electronic device ) 是由 后藤健太 笹木哲 坂口圣和 于 2020-03-16 设计创作，主要内容包括：提供连接端子和电子装置,防止外力导致的连接端子的断裂。连接端子(3)具有插入安装型连接部(3a)和大径部(3d)。插入安装型连接部(3a)的直径在从连接端子(3)的上端起的规定的长度范围内较小地形成,该插入安装型连接部(3a)在插入于设置在一个电路板(1)上的通孔(1h)的状态下,通过焊料(7)与电路板(1)的表面的焊盘(1r)连接。大径部(3d)的直径大于插入安装型连接部(3a)。插入安装型连接部(3a)与大径部(3d)之间设置有小径连续部(3b),该小径连续部(3b)形成为以与插入安装型连接部(3a)相同的直径与插入安装型连接部(3a)连续。(Provided are a connection terminal and an electronic device, which prevent the breakage of the connection terminal caused by an external force. The connection terminal (3) has an insertion-attachment type connection portion (3a) and a large diameter portion (3 d). The diameter of the insertion-mounting type connection portion (3a) is formed to be small within a predetermined length range from the upper end of the connection terminal (3), and the insertion-mounting type connection portion (3a) is connected to a land (1r) on the surface of the circuit board (1) by a solder (7) in a state of being inserted into a through hole (1h) provided in one circuit board (1). The diameter of the large diameter portion (3d) is larger than that of the insertion-attachment type connecting portion (3 a). A small-diameter continuous portion (3b) is provided between the insertion-attachment type connecting portion (3a) and the large-diameter portion (3d), and the small-diameter continuous portion (3b) is formed so as to be continuous with the insertion-attachment type connecting portion (3a) with the same diameter as that of the insertion-attachment type connecting portion (3 a).)

1. A connection terminal for electrically connecting circuit boards facing each other at a predetermined interval, the connection terminal comprising:

an insertion-mounting type connecting portion having a diameter formed to be small within a predetermined length range from an end of the connecting terminal, the insertion-mounting type connecting portion being connected to the circuit board by solder in a state of being inserted into a through hole provided in the circuit board; and

a large diameter portion having a diameter larger than the insertion-attachment type connecting portion,

it is characterized in that the preparation method is characterized in that,

the insertion-fit type connector further includes a small-diameter continuous portion formed continuously from the insertion-fit type connector with the same diameter as the insertion-fit type connector, between the insertion-fit type connector and the large-diameter portion.

2. A connecting terminal according to claim 1,

the insertion-attachment type connecting portion is composed of a buried portion buried in the through hole, a tip-side projecting portion projecting toward a side opposite to the large diameter portion with respect to the through hole, and a root-side projecting portion projecting toward the large diameter portion with respect to the through hole,

the small-diameter continuous portion is continuous from the root-side projecting portion by a predetermined length.

3. A connecting terminal according to claim 2,

the insertion-mounting type connection portion is connected to a land provided around the through hole on the surface of the circuit board by solder,

the protruding length of the root-side protruding portion from the through hole and the length of the small-diameter continuous portion are equal to or greater than the diameter from the insertion-attachment type connecting portion to the outer peripheral edge of the land.

4. A connecting terminal according to any one of claims 1 to 3,

the connection terminal further includes a tapered portion formed so that the diameter thereof gradually decreases from the large diameter portion to the small diameter continuous portion,

the taper portion has an angle of 135 ° or more with respect to the circumferential surface of the small-diameter continuous portion.

5. A connecting terminal according to any one of claims 1 to 3,

the large diameter portion has a bent portion bent in an S-shape.

6. A connecting terminal according to any one of claims 1 to 3,

the insertion-mounting type connecting portion is formed at an upper end portion of the connecting terminal,

the small-diameter continuous portion is formed so as to be continuous with a lower portion of the insertion-attachment type connecting portion.

7. A connecting terminal according to any one of claims 1 to 3,

one end of the connection terminal is formed with the insertion-mounting type connection portion connected to a pad provided on a surface of one of the circuit boards by solder,

the other end of the connection terminal is formed with a surface mounting type connection portion connected to a pad provided on the surface of the other circuit board by solder.

8. An electronic device is characterized in that a first electronic component is connected to a second electronic component,

the electronic device includes:

a connection terminal according to any one of claims 1 to 7; and

and a plurality of circuit boards which are opposed to each other at a predetermined interval and are electrically connected through the connection terminals.

Technical Field

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 boards.

Background

In an electronic device including a plurality of circuit boards, connection terminals are used to electrically connect the circuit boards to each other with a predetermined gap therebetween. Each end of the connection terminal is provided with a connection portion electrically connected to the circuit board by solder. The connection part includes an insertion-mounting type connection part and a surface-mounting type connection part.

For example, in patent document 1, an insertion-mounting type connection portion is provided at an upper end portion of a connection terminal, and a surface-mounting type connection portion is provided at a lower end portion thereof. In patent documents 2 and 3, insertion-attachment type connecting portions are provided at upper and lower ends of the connecting terminal.

The surface mounting type connecting portion is connected to a pad provided on a surface of the circuit board by solder in a state of being mounted on the pad. The insertion-mounting type connection portion is connected to a pad provided on the circuit board so as to surround a through hole provided on the circuit board by solder in a state of being inserted into the through hole.

In order to facilitate insertion into a small-diameter through hole provided in a circuit board, an insertion-mounting type connection portion may be formed to have a smaller diameter than other portions within a predetermined length range from one end of a connection terminal (patent document 1).

Stress may be applied to a connection portion between the connection terminal and the circuit board by an external force such as temperature change or vibration. In order to absorb the stress, a bent portion may be provided at a central portion of the connection terminal (patent documents 1 to 3).

Patent document 1: japanese patent laid-open No. 2007 & 242473

Patent document 2: japanese Kokai publication Sho-52-142646

Patent document 3: japanese laid-open patent publication No. 8-236178

Fig. 6 is a sectional view of a connection portion between a conventional connection terminal 50 and a circuit board 60. The circuit board 60 is provided with a through hole 61 as a through hole. Further, a land 62 is provided around the through hole 61 on the front or back surface of the circuit board 60. The insertion-fit type connection portion 51 is formed to have a smaller diameter than the other portion within a predetermined length range from one end of the connection terminal 50. The insertion-mounting type connection portion 51 is connected to the through hole 61 or the land 62 by the solder 70 in a state of 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 or back surface of the circuit board 60.

The work of connecting the insertion-mounting type connection portions 51 of the connection terminals 50 to the through holes 61 of the circuit board 60 and the like is performed by an automatic machine or a manual work. At this time, the amount of the solder 70 may vary. When the amount of the solder 70 increases, the height of the fillet of the solder 70 from the circuit board 60 increases, and a V-shaped constricted portion 80 having a sharp undulation is formed between the portion 52 of the connection terminal 50 having a larger diameter than the insertion-type connection portion 51 and the circuit board 60. 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 of the constricted portion 80 having the smallest diameter, and the connection terminal 50 may be broken at the one section X.

Disclosure of Invention

The invention aims to prevent the breakage of a connection terminal caused by external force.

The 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 and a large diameter portion. The diameter of the insertion-mounting type connection portion is formed to be small within a predetermined length range from an end of the connection terminal, and the insertion-mounting type connection portion is connected to the circuit board by solder in a state of being inserted into a through hole provided in the circuit board. The diameter of the large diameter portion is larger than that of the insertion-attachment type connecting portion. The connection terminal of the present invention further includes a small diameter continuous portion formed continuously from the insertion-fit type connection portion with the same diameter as the insertion-fit type connection portion, between the insertion-fit type connection portion and the large diameter portion.

The 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 to each other through the connection terminal.

According to the above configuration, between the large diameter portion of the connection terminal and the insertion-attachment type connection portion, the small diameter continuous portion having the same diameter as the insertion-attachment type connection portion is formed continuously with the insertion-attachment type connection portion. Thus, even if the amount of solder in the insertion-mounting type connection portion inserted into the through hole of the circuit board is large, the solder is limited to the range of the insertion-mounting type connection portion and the small-diameter continuous portion and does not reach the large-diameter portion. As a result, a V-shaped constricted portion that does not undulate sharply is not formed between the large diameter portion of the connection terminal and the circuit board. Therefore, even if external force such as temperature change or vibration is applied to the circuit board of the electronic device, shear stress generated by the external force is not concentrated on one cross section of the connection terminal between the large diameter portion and the solder. Further, since the stress is dispersed in the small-diameter continuous portion of the connection terminal, the connection terminal can be prevented from being broken by an external force.

In the present invention, the insertion-mounting type connection portion of the connection terminal may be constituted by a buried portion buried in the through hole of the circuit board, a tip-side projecting portion projecting to the opposite side of the large diameter portion with respect to the through hole, and a root-side projecting portion projecting to the large diameter portion side with respect to the through hole, and the small diameter continuous portion may be continuous from the root-side projecting portion by a predetermined length.

In the present invention, when the insertion-mounting type connection portion is connected to the land provided around the through hole in the circuit board surface by solder, the length of the protrusion of the root-side protruding portion of the insertion-mounting type connection portion from the through hole in the circuit board and the length of the small-diameter continuous portion are preferably equal to or greater than the diameter from the insertion-mounting type connection portion to the outer peripheral edge of the land, respectively.

In the present invention, the connecting terminal may further include a tapered portion formed so that a diameter thereof gradually decreases from the large diameter portion to the small diameter continuous portion of the connecting terminal. The angle of the tapered portion with respect to the circumferential surface of the small-diameter continuous portion is preferably 135 ° or more.

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

In the present invention, the insertion-attachment type connecting portion may be formed at an upper end portion of the connecting terminal, and the small-diameter continuous portion may be formed so as to be continuous with a lower portion of the insertion-attachment type connecting portion.

Further, in the present invention, an insertion-mounting type connection portion connected to a pad provided on a surface of one circuit board by solder may be formed at one end portion of the connection terminal, and a surface-mounting type connection portion connected to a pad provided on a surface of the other circuit board by solder may be formed at the other end portion of the connection terminal.

According to the present invention, breakage of the connection terminal due to external force can be prevented.

Drawings

Fig. 1 is a perspective view of a main part 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. 3 is a side view of the connection terminal and each circuit board of fig. 1.

Fig. 4 is a cross-sectional view showing an example of a connection state of the connection terminal of fig. 1 and one circuit board.

Fig. 5 is a cross-sectional view showing another example of a connection state of the connection terminal of fig. 1 and one circuit board.

Fig. 6 is a sectional view of a connection portion between a conventional connection terminal and a circuit board.

Description of the reference symbols

1. 2: a circuit board; 1 h: a through hole (through hole); 1 r: a pad; 2 p: a pad; 3: a connection terminal; 3 a: an insertion-mounting type connecting portion; 3a of₁: a front end side projecting portion; 3a of₂: a buried portion; 3a of₃: a root-side projecting portion; 3 b: a small-diameter continuous portion; 3 c: a pyramid part; 3 d: a large diameter portion; 3 e: a bending section; 3 f: a surface mount type connecting portion; 6. 7: welding flux; 10: an electronic device; d: a diameter from the insertion-mounting type connection portion to an outer peripheral edge of the pad; l1: the protruding length of the root-side protruding portion; l2: the length of the minor-diameter continuous portion; θ: the angle of the taper.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding portions are denoted by the same reference numerals.

Fig. 1 is a perspective view of a main part of an electronic device 10 of the embodiment.

The electronic device 10 is constituted by, for example, a DC-DC converter for vehicle mounting. The electronic device 10 is provided in the vicinity of a travel drive source such as an engine of a vehicle. The electronic device 10 includes circuit boards 1 and 2, a connection terminal 3, and the like. Each of the circuit boards 1 and 2 is formed of a printed board. The circuit boards 1 and 2 are mounted with electronic components constituting a DC-DC converter, and form a circuit (not shown).

Spacers 4 are provided between the plurality of corner portions 1k of the circuit board 1 and the plurality of corner portions 2k of the circuit board 2. The circuit board 1 is fixed to the upper surface of each spacer 4 by screws 5. The circuit board 2 is fixed to the lower surface of each spacer 4 by screws (not shown). Thus, the circuit board 1 and the circuit board 2 are arranged 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, 2 to each other. In fig. 1, the circuit boards 1 and 2 are electrically connected by two connection terminals 3, but the number of the connection terminals 3 may be one, or may be three or more.

Fig. 2 is a perspective view of the connection terminal 3. Fig. 3 is a side view of the connection terminal 3 and the respective circuit boards 1, 2. Fig. 4 is a cross-sectional view showing an example of a connection state of the connection terminal 3 and one circuit board 1. Fig. 5 is a cross-sectional view showing another example of the connection state of the connection terminal 3 and one circuit board 1.

As shown in fig. 2, the connection terminal 3 is formed by punching out a metal plate having conductivity and then bending the metal plate.

An insertion-mounting type connecting portion 3a is formed at an upper end portion of the connection terminal 3. Specifically, the insertion-attachment type connection portion 3a is formed within a predetermined length range from the upper end of the connection terminal 3.

The diameter of the insertion-attachment type connecting portion 3a is smaller than the diameter of the large diameter portion 3d from the center to the lower end of the connection terminal 3. Specifically, since the board thickness of the connection terminal 3 is the same over the entire length of the connection terminal 3, the width of the insertion-fit connection portion 3a is smaller than the width of the large diameter portion 3d as shown in fig. 3 to 5.

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-attachment type connection portion 3 a. The small-diameter continuous portion 3b is formed continuously with the connecting portion 3a with the same diameter (the same width) as the insertion-attachment connecting portion 3 a. The tapered portion 3c is formed such that the diameter (width) thereof gradually decreases from the large diameter portion 3d to the small diameter continuous portion 3 b.

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

As shown in fig. 1 and 3, the surface-mount type connection portion 3f is connected to a pad 2p provided on the upper surface (surface) of the circuit board 2 by solder 6 in a state of being placed on the pad 2 p. The steps of placing and connecting the surface-mount type connecting portion 3f are performed by an automatic machine or a manual operation. The pad 2p is electrically connected to a circuit (not shown) formed on the circuit board 2.

In order to increase the bonding area between the surface-mount type connection portion 3f and the solder 6, as shown in fig. 2, the surface-mount type connection portion 3f is formed with a through hole 3 g. The solder 6 enters the through hole 3 g.

As shown in fig. 4 and 5, the circuit board 1 is provided with a through hole 1 h. The through hole 1h is constituted by a hole (reference numeral omitted) formed in the circuit board 1 and conductors (reference numeral omitted) provided on the inner peripheral surface and the open end of the hole. A land 1r is provided around the through hole 1h on the upper surface (front surface) and the lower surface (back surface facing the circuit board 2) of the circuit board 1. The through hole 1h is an example of the "through hole" of the present invention.

The insertion-mounting type connection portion 3a of the connection terminal 3 is electrically connected to the through hole 1h provided in the circuit board 1 or the pad 1r provided around the through hole 1h by the solder 7 in a state of being inserted into the through hole 1 h. The insertion and connection steps of the insertion-attachment type connecting portion 3a are performed by an automatic machine or manual work. The through hole 1h or the land 1r is electrically connected to a circuit formed on the circuit board 1 (not shown).

The insertion-mounting type connecting portion 3a is formed by a buried portion 3a buried in the through hole 1h₂A front end side protruding portion 3a protruding to the opposite side of the large diameter portion 3d with respect to the through hole 1h₁And a base-side projecting portion 3a projecting toward the large-diameter portion 3d with respect to the through hole 1h₃And (4) forming.

On the upper and lower surfaces of the circuit board 1, protruding portions 3a from the insertion-mounting type connection portions 3a₁、3a₃A fillet of solder 7 is formed to the outer peripheral edge of the pad 1 r. The height of the fillet of the solder 7 formed on the lower surface of the circuit board 1 is higher than the height of the fillet of the solder 7 formed on the upper surface of the circuit board 1 due to the gravity of the solder 7.

The small-diameter continuous portion 3b protrudes from the root-side protruding portion 3a of the insertion-attachment type connecting portion 3a₃Starting from the lower part and continuing with a predetermined length. Root-side projecting part 3a₃The protrusion length L1 from the through hole 1h is set to be equal to or greater than the diameter D (L1 ≧ D) from the insertion-mounting type connecting portion 3a to the outer peripheral edge of the pad 1 r. The length L2 of the small-diameter continuous portion 3b is also set to be equal to or larger than the diameter D (L2 ≧ D) from the insertion-mounting type connecting portion 3a to the outer peripheral edge of the land 1 r.

As described above, since the process of connecting the insertion-mounting type connection portion 3a to the through-hole 1h and the pad 1r by the solder 7 is performed by an automatic machine or a manual operation, the amount of the solder 7 varies.

In the case where the amount of solder 7 is small, as shown in fig. 4, fillets of the solder 7 generated on the lower surface of the circuit board 1 are formed on the root-side projecting portions 3a of the insertion-and-mounting type connecting portions 3a₃Within the range of (1).

On the other hand, in the case where the amount of the solder 7 is large, as shown in fig. 5, the fillet of the solder 7 generated on the lower surface of the circuit board 1 is formed to exceed the root side protruding portion 3a₃And extends to a part of the range of the small-diameter continuous portion 3 b.

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 does not reach the tapered portion 3c or the large diameter portion 3d having a diameter larger than that of the insertion-mounting type connecting portion 3a or the small diameter continuous portion 3 b. Therefore, although the neck portion 8 having a gentle undulation is formed between the large diameter portion 3d of the connection terminal 3 and the circuit board 1, the conventional V-shaped neck portion 80 having a sharp undulation as shown in fig. 6 is not formed.

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 (a cross section in the left-right direction in fig. 3 to 5) perpendicular to the longitudinal direction (the up-down direction in fig. 3 to 5) of the connection terminal 3 is 45 ° or more. Thus, the diameter (width) of the connection terminal 3 is gently changed at the tapered portion 3c, and the undulation of the constricted portion 8 generated between the large diameter portion 3d and the circuit board 1 is further alleviated.

As described above, the electronic device 10 is disposed in the vicinity of the travel drive source of the vehicle, and therefore, large vibration or impact generated in the travel drive source is transmitted to the electronic device 10. Moreover, thermal shock caused by ambient temperature changes is also transmitted to the electronic device 10.

When 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 swing, and stress generated by the external force is applied to the connection terminals 3. As shown in fig. 4 and 5, the shear stress τ generated in the left-right direction among the stresses is dispersed in the small-diameter continuous portion 3b of the connection terminal 3 not covered with the solder 7. Then, as shown in fig. 3, the stress σ generated in the vertical direction is absorbed by the bent portion 3e of the connection terminal 3. Therefore, the connection terminals 3 themselves are prevented from being broken by an external force or the connection portions (solder 7) of the connection terminals 3 and the circuit boards 1, 2 are prevented from being damaged.

According to the above embodiment, between the large diameter portion 3d of the connection terminal 3 and the insertion-fit type connection portion 3a, the small diameter continuous portion 3b having the same diameter as the insertion-fit type connection portion 3a is formed so as to be continuous with the connection portion 3 a. Thus, even if the amount of solder 7 connecting the insertion-mounting-type connection portion 3a inserted into the through hole 1h of the circuit board 1 to the land 1r is large, the solder 7 on the lower surface side of the circuit board 1 is limited to the range of the insertion-mounting-type connection portion 3a and the small-diameter continuous portion 3b, and does not reach the tapered portion 3c or the large-diameter portion 3 d. Even if the solder 7 accumulates on the lower surface side more than the upper surface side of the circuit board 1 due to gravity, the solder 7 does not reach the tapered portion 3c or the large diameter portion 3 d. As a result, the V-shaped constricted portion having a sharp undulation as shown in fig. 6 is not generated between the large diameter portion 3d of the connection terminal 3 and the circuit board 1. Therefore, even if an external force such as a temperature change or vibration is applied to the circuit boards 1 and 2 of the electronic device 10, the shear stress τ generated by the external force is not concentrated on one cross section of the connection terminal 3 between the large diameter portion 3d and the solder 7. Further, since the stress is dispersed in the small-diameter continuous portion 3b of the connection terminal 3, the connection terminal 3 can be prevented from being broken by an external force.

In the above embodiment, the small-diameter continuous portion 3b of the connection terminal 3 protrudes from the root-side protruding portion 3a of the insertion-attachment type connection portion 3a protruding downward from the through hole 1h₃Are continuous with a predetermined length. Therefore, the solder 7 connecting the insertion-mounting-type connection portion 3a to the circuit board 1 can be reliably prevented from reaching a portion (the tapered portion 3c or the large diameter portion 3d) having a larger diameter than the insertion-mounting-type connection portion 3a or the small diameter continuous portion 3 b. Further, the undulation of the constricted portion 8 generated between the large diameter portion 3d of the connection terminal 3 and the circuit board 1 can be further alleviated. As a result, the shear stress τ generated by the external force can be further dispersed in the small diameter continuous portion 3b of the connection terminal 3, and the breakage of the connection terminal 3 can be more effectively prevented.

In addition, in the above embodiment, the root-side projecting portion 3a₃The length L1 of the protrusion from the through hole 1h and the length L2 of the small-diameter continuous portion 3b are equal to or greater than the diameter D of the outer peripheral edge of the land 1r from the insertion-attachment-type connector 3a to the periphery of the through hole 1 h. Therefore, the fillet of the solder 7 on the lower surface side of the circuit board 1 is formed as far as possible from the large diameter portion 3d of the connection terminal 3, and the undulation of the constricted portion 8 generated between the large diameter portion 3d of the connection terminal 3 and the circuit board 1 can be further alleviated.

In the above embodiment, the angle θ of the tapered portion 3c with respect to the circumferential surface of the small diameter continuous portion 3b of the connection terminal 3 is 135 ° or more. Therefore, the undulation of the constricted portion 8 generated between the large diameter portion 3d of the connection terminal 3 and the circuit board 1 can be further alleviated.

By relaxing the undulation of the constricted portion 8 as described above, the shear stress τ generated by the external force is less likely to concentrate on one cross section of the connection terminal 3 that traverses the constricted portion 8 in the right and left directions. In particular, the shear stress τ generated by the external force is less likely to concentrate on a section passing through the boundary between the small-diameter continuous portion 3b and the tapered portion 3 c. Therefore, the connection terminals 3 can be prevented from being broken at these cross-sectional portions.

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

The present invention can be implemented in various embodiments other than the above-described embodiments.

For example, in the above embodiment, the example in which the insertion-attachment type connection portion 3a is provided at one end portion of the connection terminal 3 is described, but the present invention is not limited thereto. Instead of the surface-mount-side connection portion 3f, an insertion-mount-type connection portion may be provided at the other end of the connection terminal 3.

In the above embodiment, the 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. For example, a stepped portion having a diameter that changes discontinuously may be provided between the small-diameter continuous portion 3b and the large-diameter portion 3d instead of the tapered portion 3 c.

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

In the above embodiment, the example in which the connection terminal 3 is formed by processing the metal plate has been described, but the present invention is not limited to this. Alternatively, for example, the connection terminal 3 may be formed by processing a metal wire rod.

Further, in the above embodiment, the example in which the present invention is applied to the electronic device 10 including the DC-DC converter for vehicle mounting provided in the vicinity of the travel drive source of the vehicle and the connection terminal 3 provided in the electronic device 10 has been described, but the present invention may be applied to other electronic devices for vehicle mounting, electronic devices other than those for vehicle mounting, and connection terminals provided in the electronic devices.