Terminal joining structure of bus bar

Abstract

The invention provides a terminal joining structure of a bus bar, which can stably maintain the position relation between a joining part of the bus bar and a terminal to obtain a good joining state when the bus bar and the terminal of an electronic device are joined by welding. The terminal joining structure of the bus bar includes: a welded portion on which a joining surface joined to a tip portion of a rod-shaped terminal by welding is disposed; and a terminal holding part which is provided at a position separated from the welded part, and which restricts the movement of the terminal in the welded part by inserting the base end part of the terminal.

Description

Technical Field

[0001] The present invention relates to a terminal joint structure of a bus bar. Background Art

[0002] A bus bar is a conductive member for supplying power, and is particularly used as a wiring for passing large currents. In the field of automotive electronics, a PCU (Power Control Unit) is used, which is equipped with multiple power semiconductor devices such as IGBTs (Insulated Gate Bipolar Transistors). Bus bars are used to connect control boards of the PCU and to connect control boards with electronic devices (drive devices, heat generating devices, etc.).

[0003] If soldering is used to join the bus bar and the terminal of the electronic device, it is easy to cause cracks in the joint and reduce the mechanical strength. Therefore, joining is performed by welding using a high energy density heating source such as laser or plasma (for example, see the following patent document 1).

[0004] Patent Document 1: Japanese Patent Application Publication No. 2006-179197

[0005] When a bus bar and an electronic device terminal are joined by welding, it is important to stably maintain the positional relationship between the joining portion of the bus bar and the terminal in order to avoid joining failure.

[0006] For example, in the connection between the rod-shaped terminal and the bus bar, the connection part of the bus bar is generally processed into a roughly U-shape to surround the rod-shaped terminal. At this time, if welding is performed with the rod-shaped terminal inserted inside the roughly U-shaped connection part, the gap between the connection part of the bus bar and the rod-shaped terminal is enlarged due to the heat during welding, and welding is sometimes performed with the rod-shaped terminal located at a position offset from the enlarged gap. In this case, there is a problem that the thickness of the molten part around the rod-shaped terminal varies and the welding accuracy is unstable. Summary of the invention

[0007] The present invention aims to address such a problem. Specifically, the present invention aims to stably maintain the positional relationship between the joining portion of the bus bar and the terminal when joining the bus bar and the electronic device terminal by welding to obtain a good joining state.

[0008] In order to solve such a problem, the terminal joining structure of the bus bar of the present invention has the following structure. The terminal joining structure of a busbar is used to join a busbar and a terminal of an electronic device by welding, and the terminal joining structure of the busbar comprises: a welded portion, which is provided with a joining surface which is joined to the top end portion of the rod-shaped terminal by welding; and a terminal retaining portion, which is arranged at a position away from the welded portion and restricts the movement of the terminal in the welded portion by inserting the base end portion of the terminal.

[0009] According to the present invention having such features, when the bus bar and the electronic device terminal are joined by welding, the positional relationship between the joining portion of the bus bar and the terminal can be stably maintained, thereby obtaining a good joining state. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is an explanatory diagram (perspective view) showing a terminal joining structure of a bus bar according to an embodiment of the present invention. Figure 2 It is an explanatory diagram (side view) showing a terminal joining structure of a bus bar according to an embodiment of the present invention. Figure 3 This is an explanatory diagram (AA cross-sectional view) showing a terminal joining structure of a bus bar according to an embodiment of the present invention. Figure 4 It is an explanatory diagram (BB cross-sectional view) showing a terminal joining structure of a bus bar according to an embodiment of the present invention. Figure 5 This is an explanatory diagram (CC cross-sectional view) showing a terminal joining structure of a bus bar according to an embodiment of the present invention. Figure 6 It is an explanatory diagram of a heating device including a terminal joining structure of a bus bar according to an embodiment of the present invention. DETAILED DESCRIPTION

[0011] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, the same reference numerals in different drawings represent parts with the same functions, and repeated descriptions in the drawings will be omitted as appropriate.

[0012] exist Figure 1 to Figure 5 , an example of a terminal joining structure 1 is shown in which a rod-shaped (round rod-shaped in the example shown) terminal 2 in an electronic device (not shown) is joined to a bus bar 10 by welding. The bus bar 10 has a welded portion 10A, a terminal holding portion 10B, and a connecting portion 10C connecting the welded portion 10A and the terminal holding portion 10B as the terminal joining structure 1.

[0013] The welded portion 10A of the bus bar 10 has joint surfaces (first joint surface 11, second joint surface 12, and third joint surface 13) that are welded to the tip portion 2A of the terminal 2. The welded portion 10A is heated by laser irradiation or the like to melt and join the terminal 2 and the bus bar 10.

[0014] like Figure 3 As shown, the welded portion 10A has a first joint surface 11 and a second joint surface 12, and the first joint surface 11 and the second joint surface 12 are arranged in a pair across the side surface of the top end portion 2A of the terminal 2. In addition, in the example shown in the figure, there is a third joint surface 13 that is opposite to the side surface of the terminal 2 in a direction different from the first joint surface 11 and the second joint surface 12. Furthermore, the welded portion 10A has a guide portion 14 that guides the side surface of the terminal 2 at the end after the first joint surface 11 and the second joint surface 12 are folded back.

[0015] In the welded portion 10A, the tip portion 2A of the terminal 2 is arranged in a space sandwiched between the first joint surface 11 and the second joint surface 12, and in a space sandwiched between the third joint surface 13 and the guide portion 14. When welding, it is important to arrange the tip portion 2A of the terminal 2 without deviation in the space sandwiched between the first joint surface 11 and the second joint surface 12 and the space sandwiched between the third joint surface 13 and the guide portion 14 in order to stabilize the welding accuracy.

[0016] At this time, the guide portion 14 prevents the tip portion 2A of the terminal 2 from being inserted obliquely with respect to the welded portion 10A. The guide portion 14 can restrict the posture of the terminal 2 in the welded portion 10A to be substantially parallel to the third joint surface 13 .

[0017] On the other hand, the terminal holding portion 10B of the bus bar 10 is provided at a position away from the welded portion 10A, and the base end portion 2B of the terminal 2 is inserted therein, thereby restricting movement of the terminal 2 in the welded portion 10A.

[0018] More specifically, if Figure 4 As shown, the terminal holding portion 10B has a pair of opposing restriction surfaces (a first restriction surface 21 and a second restriction surface 22 ). In addition, the terminal holding portion 10B has a third restriction surface 23 that restricts the position of the terminal 2 from a direction different from the first restriction surface 21 and the second restriction surface 22 .

[0019] Furthermore, the gap between the terminal 2 and the terminal holding portion 10B is narrower than the gap between the terminal 2 and the welded portion 10A. Figure 3 As shown, in the terminal holding portion 10A, a gap having a gap width t1 is provided between the terminal 2 disposed between the first joint surface 11 and the second joint surface 12 and the first joint surface 11 or the second joint surface 12. Figure 4 As shown, in the terminal holding portion 10B, a gap having a gap width t2 exists between the terminal 2 disposed between the first restriction surface 21 and the second restriction surface 22 and the first restriction surface 21 or the second restriction surface 22 , where t2<t1.

[0020] The terminal holding portion 10B is separated from the welded portion 10A via the connecting portion 10C, thereby becoming a portion that is not easily affected by heat during welding. Therefore, even if the gap in the welded portion 10A is enlarged during welding, the position of the terminal 2 is restricted and maintained by the terminal holding portion 10B that is not easily affected by heat during welding, thereby restricting the movement of the terminal 2 in the welded portion 10A. As a result, the positional relationship between the joint portion (welded portion 10A) of the bus bar 10 and the terminal 2 can be stably maintained during welding, and a good joint state can be obtained.

[0021] like Figure 5 As shown, the guide portion 14 provided in the welded portion 10A is provided with a tapered guide portion 14T, and the tapered guide portion 14T moves away from the third joint surface 13 as it moves toward the terminal holding portion 10B. The tapered guide portion 14T is continuously provided from the end portion of the guide portion 14 parallel to the third joint surface 13, and has a function of smoothly inserting the top end portion 2A of the terminal 2 into the above-mentioned space in the welded portion 10A.

[0022] like Figure 6 As shown, the above-described terminal joining structure 1 can be adopted when joining the bus bar 10 to the terminal 2 of the heater 200 . Figure 6 1 shows a heating device 100 using the terminal joint structure 1. The heating device 100 heats the heat medium flowing in the flow channel 201 by arranging the heater 200 in the flow channel 201 formed in the housing 101 through which the heat medium flows. A heat-resistant sealing member 202 is provided around the heater 200 arranged in the housing 101 to block the heat medium from the flow channel 201.

[0023] In the heating device 100, the other end of the bus bar 10, one end of which is joined to the terminal 2 of the heater 200, is connected to the control substrate 103 on which the temperature sensor 105 and the like are mounted via the relay component 110. That is, the bus bar 10 is used as a power supply wiring between the control substrate 103 and the heater 200. The control substrate 103 is fixed to the end of the support protrusion 102 supported in the box 101 by the fixing screw 103P.

[0024] A circuit component 104 such as an IGBT unit is placed on a placement surface 101A of the housing 100 in the heating device 100. A circuit component terminal 104A of the circuit component 104 is connected to the control substrate 103. Here, the placement surface 101A is arranged away from the installation position of the heater 200, so as to thermally protect the circuit component 104. The circuit component 104 is pressed and supported on the placement surface 101A by a fixing member 104 having one end fixed to the housing 101 by a fixing screw 104.

[0025] If the above-mentioned terminal joint structure 1 is adopted in such a heating device 100, when the bus bar 10 and the terminal 2 of the heater 200 are joined by welding, the positional relationship between the joint portion of the bus bar 10 and the terminal 2 can be stably maintained to obtain a good joint state. Thus, the heating device 100 can be operated stably.

[0026] As described above, according to the terminal joint structure 1 of the bus bar 10 of the embodiment of the present invention, the terminal holding portion 10B is provided at a position away from the welded portion 10A in the joint portion of the bus bar 10, so that even when the terminal 2 and the bus bar 10 are molten at the welded portion 10A during welding, the terminal holding portion 10B holds the position of the terminal 2 in the welded portion 10A. Thus, stable welding can be performed, and the welding accuracy in terminal joint can be improved.

[0027] In addition, since the guide portion 14 is provided in the welded portion 10A, the tip portion 2A of the terminal 2 can be prevented from being inserted obliquely relative to the welded portion 10A. In addition, the guide portion 14 can be used to restrict the posture of the terminal 2 in the welded portion 10A to be substantially parallel to the third joint surface 13. Furthermore, since the guide portion 14 is provided with a tapered guide portion 14T, the terminal 2 can be smoothly inserted into the space of the welded portion 10A.

[0028] The embodiments of the present invention are described in detail with reference to the accompanying drawings, but the specific structure is not limited to these embodiments, and design changes within the scope of the present invention are also included in the present invention. In addition, as long as there are no special contradictions or problems in the purpose and structure of the above-mentioned embodiments, the technology of each other can be used for combination. Description of Reference Numerals

[0029] 1: Terminal joint structure, 2: terminal, 2A: top end, 2B: base end, 10: bus bar, 10A: welded portion, 10B: terminal holding portion, 10C: connecting portion, 11: first joint surface, 12: second joint surface, 13: third joint surface, 14: guide part, 14T: tapered guide part, 21: first limiting surface, 22: second limiting surface, 23: third limiting surface, 100: heating device, 101: box body, 101A: bearing surface, 102: supporting protrusion, 103: Control board, 103P: Fixing screw, 104: circuit component (IGBT unit), 104A: circuit component terminal, 104B: fixing screw, 104C: fixing piece, 105: temperature sensor, 110: relay component, 200: heater, 201: flow channel, 202: sealing member.

Claims

1. A terminal joining structure of a bus bar, used for joining a bus bar and a terminal of an electronic device by welding, wherein the terminal joining structure of the bus bar is characterized by having: a welded portion having a joining surface to be joined to a tip end portion of the rod-shaped terminal by welding; and The terminal holding portion is provided at a position away from the welded portion and restricts movement of the terminal in the welded portion by inserting the base end portion of the terminal.

2. The terminal joint structure of the bus bar according to claim 1, characterized in that: A gap between the terminal and the terminal in the terminal holding portion is narrower than a gap between the terminal and the terminal in the welded portion.

3. The terminal joint structure of the bus bar according to claim 1, characterized in that: The welded portion includes a first joint surface and a second joint surface arranged as a pair across the side surface of the terminal, and a third joint surface facing the side surface of the terminal in a direction different from the first joint surface and the second joint surface.

4. The terminal joint structure of the bus bar according to claim 3, characterized in that: The welded portion includes a guide portion for guiding a side surface of the terminal at an end portion where the first joint surface and the second joint surface are folded back.

5. The terminal joint structure of the bus bar according to claim 4, characterized in that: The guide portion has a tapered guide portion that becomes more distant from the third joint surface as it moves toward the terminal holding portion.

6. A heating device, characterized in that: A bus bar terminal joining structure according to any one of claims 1 to 5, wherein the terminal is a heater terminal.

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