Power converter

Abstract

To provide a power conversion device capable of reducing a stress to a junction between a connector terminal and a circuit board.SOLUTION: A power conversion device comprises: a circuit board; a conductive housing; a connector; a plurality of first fastening members for fastening the connector to the circuit board; and a plurality of second fastening members for fastening the connector and the circuit board together to the housing. The connector has a connector terminal. The plurality of first fastening members are arranged so as to surround the periphery of a region where the connector terminal is connected on the circuit board. The plurality of second fastening members are conductive and inserted into a first through-hole formed on the circuit board and a second through-hole formed on the connector to fasten the connector and the circuit board together to the housing.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to a power conversion device.

Background Art

[0002] A power conversion device has a configuration in which a circuit board and a connector are connected. However, a structure that can maintain the reliability of the device is required for the mounting method of the circuit board. For example, Patent Document 1 below discloses a power conversion device having a structure in which a connector and a circuit board are fastened together to be fastened to a housing.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the configuration described in Patent Document 1, for the connector fastened to the circuit board, the joint portion of the connector terminal joined to the circuit board with solder is likely to have reduced joint reliability when stress such as deflection occurs with respect to the circuit board. In view of this, an object of the present invention is to provide a power conversion device that reduces stress on the joint between the connector terminal and the circuit board.

Means for Solving the Problems

[0005] The power converter comprises a circuit board electrically connected to a power module that drives a motor, a conductive housing that houses the circuit board, a connector for connecting to external equipment, a plurality of first fastening members for fastening the connector to the circuit board, and a plurality of second fastening members for fastening the connector and the circuit board together to the housing. The connector has connector terminals that electrically connect to the circuit board, the plurality of first fastening members are arranged on the circuit board to surround the area to which the connector terminals are connected, and the plurality of second fastening members are conductive and fasten the connector, the circuit board and the housing together by inserting them through a first through hole formed in the circuit board and a second through hole formed in the connector. [Effects of the Invention]

[0006] According to the present invention, it is possible to provide a power conversion device that reduces stress on the joint between the connector terminal and the circuit board. [Brief explanation of the drawing]

[0007] [Figure 1] Perspective view of a power converter [Figure 2] Exploded perspective view of a power converter. [Figure 3] An overhead view of a circuit board sub-assembly component inside a power converter according to one embodiment of the present invention. [Figure 4] Perspective view of a circuit board sub-assembly component connected to a connector. [Figure 5] Perspective view of the connector [Figure 6] Cross-sectional view AA of Figure 3 relating to one embodiment of the present invention [Figure 7] Enlarged view of the insertion portion of the second fastening component according to one embodiment of the present invention. [Figure 8] First variation [Figure 9] Second variation

[0008] Embodiments of the present invention will be described below with reference to the drawings. The following description and drawings are illustrative for illustrating the present invention, and have been omitted and simplified as appropriate for clarity of explanation. The present invention can also be carried out in various other forms. Unless otherwise specified, each component may be singular or plural.

[0009] The positions, sizes, shapes, and ranges of the components shown in the drawings may not represent their actual positions, sizes, shapes, and ranges in order to facilitate understanding of the invention. Therefore, the present invention is not necessarily limited to the positions, sizes, shapes, and ranges disclosed in the drawings.

[0010] (An embodiment of the present invention and the overall configuration of the apparatus) (Figure 1) The power converter 100 has a cover 10 and a housing 20. The cover 10 seals the components housed inside the housing 20 by closing the opening formed in the housing 20. A portion of the connector 40 housed inside the housing 20 protrudes from the outside of the housing 20.

[0011] (Figure 2) The power converter 100 includes a circuit board 30 (hereinafter referred to as the board 30) electrically connected to a power module 60 that drives a motor, a conductive housing 20 that houses the board 30, and a connector 40 for connecting to external equipment. The circuit board sub-assembly 200 (hereinafter referred to as the sub-assembly 200) has the connector 40 and the board 30. In the power converter 100, the shielding plate 50 is positioned between the power module 60 and the board 30. The shielding plate 50 is a shielding component that shields against noise generated by the switching operation of the power module 60 from propagating through space and being transmitted to the board 30.

[0012] (Figure 3) The connector 40 is connected and fixed to the substrate 30 by the first fastening member 1 and the second fastening member 2. The first fastening member 1 and the second fastening member are, for example, screws. Further, the substrate 30 has a solder portion 201 which is a joining portion of the connector terminals 43 that the connector 40 has.

[0013] The plurality of first fastening members 1 are arranged so as to surround the periphery of the region 202 on the substrate 30 where the connector terminals 43 are connected. The solder portion 201 is provided so as to be accommodated within the region 202 formed by connecting the plurality of first fastening members 1 to each other. Also, the second fastening member 2 is arranged on the substrate 30 outside the region 202 surrounded by the first fastening member 1. The first fastening member 1 is the fastening member closest to the solder portion 201 among the plurality of fastening members on the substrate 30 for fastening to each component.

[0014] With such a configuration, when assembling the connector 40 to the substrate 30, even if there are dimensional variations in the assembly, the deflection of the substrate 30 is less likely to be propagated into the region 202. In particular, the distortion of the substrate 30 generated outside the region 202 is less likely to be propagated into the region 202. Therefore, the stress on the solder portion 201 can be reduced.

[0015] Note that the first fastening member 1 is not limited to being formed by surrounding the region 202 on four sides as long as the purpose of reducing the stress on the solder portion 201 can be achieved, and it may be formed by surrounding it at three points or five or more points.

[0016] (Fig. 4) In the sub-component 200, the connector 40 is fastened to the substrate 30 by the first fastening member 1. The connector terminals 43 of the connector 40 are soldered to the solder portion 201 within the region 202 (see FIG. 4) surrounded by the plurality of first fastening members 1. Thereby, for example, when assembling the sub-component 200 to the housing 20 on the assembly line, due to the same effect as described above, no distortion or stress is generated in the solder portion 201. Also, in the assembly process of the power conversion device 100, by first assembling and soldering the substrate 30 and the connector 40 as the sub-component 200, it leads to a reduction in the rework man-hours due to solder defects and can reduce the loss cost.

[0017] (FIG. 5) The connector 40 is an interface component with external devices in the power conversion device 100. The connector 40 has a resin housing 44. The resin housing 44 holds a pair of spacers 41, a plurality of nuts 42, and connector terminals 43.

[0018] (FIG. 6) The substrate 30 is provided with a plurality of first fastening members 1 for fastening the connector 40 to the substrate 30, and a plurality of second fastening members 2 for jointly fastening and fixing the connector 40 and the substrate 30 to the housing 20. The connector 40 has connector terminals 43 that are electrically connected to the substrate 30.

[0019] The spacer 41 serves as a through-hole through which the second fastening member 2 is inserted. The second fastening member 2 prevents the generation of distortion on the substrate 30 caused by the insertion and extraction of the connector 40 with external devices, for example, in the scenarios of quality control and inspection, by fastening and fixing the connector 40 to the housing 20.

[0020] The nut 42 is screwed into the first fastening member 1 which is inserted into the circuit board 30. The circuit board 30 and the connector 40 are fastened and fixed by the first fastening member 1, forming a soldered portion 201 where the circuit board 30 and the connector terminals 43 are soldered together. In addition, the connector 40 is subjected to insertion and removal forces when connecting to external devices, but the distortion of the circuit board 30 is reduced by fastening and fixing the connector 40 to the housing 20 with the second fastening member 2 against these external forces.

[0021] (Figure 7) The second fastening member 2 fastens the connector 40, the substrate 30, and the housing 20 together by inserting it through the first through hole 30a formed in the substrate 30 and the second through hole 40a formed in the connector 40. The substrate 30 has a first ground pattern 32 on the side facing the housing 20 and a second ground pattern 34 on the side opposite to the side facing the housing 20.

[0022] The insulating film 31 covers the surface of the substrate 30. The first ground pattern 32 and the second ground pattern 34 are conductive layers of potential ground formed within the substrate 30. An insulating layer 33 is provided between the first ground pattern 32 and the second ground pattern 34. The insulating layer 33 is an insulating layer formed within the substrate 30.

[0023] The housing 20 is screwed into the conductive second fastening member 2. The housing 20 is a conductive and ground potential member. Noise currents 3A and 3B are noise currents originating from the switching of the power module 60 or external equipment, with the second noise current 3B transmitting over the first ground pattern 32 and the first noise current 3A transmitting over the second ground pattern 34.

[0024] An exposed portion 34a (second exposed portion 34a) of the second ground pattern 34 is provided between the second fastening member 2 and the insulating film 31. This exposed portion 34a causes the second fastening member 2 to be in contact with the second ground pattern 34. Since the second fastening member 2 is a conductive material, the second ground pattern 34 is electrically connected to the housing 20 via the second fastening member 2.

[0025] In this way, regarding the noise current transmitted through the second ground pattern 34 of the substrate 30, conventionally, the noise current was discharged from the substrate 30 to the housing 20 via a shielding plate or the like, but in the present invention, the noise current is discharged to the housing 20 via a shorter path 4A than in the conventional method. As a result, the impedance is reduced, and the first noise current 3A transmitted over the second ground pattern 34 flows more easily to the housing 20, thereby reducing the noise's impact on external devices via the connector 40.

[0026] A conductive bushing, or spacer 41, is provided between the substrate 30 and the housing 20, positioned inside the second through-hole 40a. The spacer 41 is inserted through a through-hole (second through-hole 40a) provided in the resin housing 44. An exposed portion 32a (first exposed portion 32a) of the first ground pattern 32 is provided between the spacer 41 and the insulating film 31. The spacer 41 electrically connects the first ground pattern 32 and the housing 20.

[0027] In this way, the second noise current 3B transmitted through the first ground pattern 32 can be discharged to the housing 20 via the current path 4B through the spacer 41. In other words, the current path 4B provided by this configuration is shorter in length and has lower impedance compared to conventional designs. Therefore, the second noise current 3B transmitted over the first ground pattern 32 can flow more easily into the housing 20, and similarly, the noise impact on external equipment can be reduced.

[0028] Furthermore, the first fastening member 1 only needs to be used to fasten and secure the connector 40 to the substrate 30, and therefore does not need to be a conductive material like the second fastening member 2.

[0029] (First variation) (Figure 8) A shielding plate 50 is provided between the connector 40 and the housing 20, and the shielding plate 50 is fastened to the housing 20 by a second fastening member 2. The switching operation of the power module 60 generates noise 3C that propagates through space, but by fastening the shielding plate 50 to the housing 20 together with the second fastening member 2, the spatial connection to the circuit board 30 is shielded by the shielding plate 50, preventing the noise 3C from propagating through space and reaching the circuit board 30. This reduces the leakage of noise to external equipment.

[0030] (Second variation) (Figure 9) The connector 40 has the same stress reduction effect even when, during assembly to the circuit board 30, the insertion direction of the first fastening member 1 is different from that of the second fastening member 2, and the connector 40 is not positioned on the housing 20 side of the circuit board 30.

[0031] According to the embodiment of the present invention described above, the following effects are achieved.

[0032] (1) The power converter 100 comprises a circuit board 30 electrically connected to a power module 60 that drives a motor, a conductive housing 20 that houses the circuit board 30, a connector 40 for connecting to external equipment, a plurality of first fastening members 1 for fastening the connector 40 to the circuit board 30, and a plurality of second fastening members 2 for fastening the connector 40 and the circuit board 30 together to the housing 20. The connector 40 has connector terminals 43 that are electrically connected to the circuit board 30, the plurality of first fastening members 1 are arranged on the circuit board 30 so as to surround the area to which the connector terminals 43 are connected, and the plurality of second fastening members 2 are conductive and fasten the connector 40 and the circuit board 30 together to the housing 20 by inserting them through a first through hole 30a formed in the circuit board 30 and a second through hole 40a formed in the connector 40. In this way, a power converter 100 can be provided that reduces stress on the joint (solder joint 201) between the connector terminal 43 and the circuit board 30.

[0033] (2) The second fastening member 2 is positioned on the circuit board 30 outside the region 202 surrounded by the first fastening member 1. This arrangement prevents the distortion around the second fastening member 2 during assembly from affecting region 202.

[0034] (3) The circuit board 30 has a first ground pattern 32 on the side facing the housing 20 and a second ground pattern 34 on the side opposite to the side facing the housing 20, and the second fastening member 2 electrically connects the second ground pattern 34 to the housing 20. This reduces impedance, making it easier for the first noise current 3A transmitted over the second ground pattern 34 to flow into the housing 20, thereby reducing the noise's impact on external devices via the connector 40.

[0035] (4) A conductive spacer 41 is provided between the circuit board 30 and the housing 20, positioned inside the second through-hole 40a, and the spacer 41 electrically connects the first ground pattern 32 and the housing 20. This reduces the impedance, making it easier for the second noise current 3B that has been transmitted over the first ground pattern 32 to flow into the housing 20, thereby reducing the noise's impact on external devices via the connector 40.

[0036] (5) A shielding plate 50 is provided between the connector 40 and the housing 20, and the shielding plate 50 is fastened to the housing 20 by the second fastening member 2. This prevents noise generated by the switching of the power module 60 from propagating through space and being transmitted to the circuit board 30.

[0037] It should be noted that the present invention is not limited to the embodiments described above, and various modifications and combinations of other configurations can be made without departing from the spirit of the invention. Furthermore, the present invention is not limited to having all the configurations described in the embodiments described above, and may also include configurations in which some of those configurations are omitted. [Explanation of Symbols]

[0038] 1. First fastening member 2. Second fastening member 3A First noise current 3B Second Noise Current 3C Noise 4A Shortest Path 4B Shortest path 10 Covers 20 cabinets 30 Circuit boards 30a First through hole 31 Insulating Film 32. First Ground Pattern 32a 1st exposed part 33 Insulating layer 34. Second Ground Pattern 34a 2nd exposed part 40 connectors 40a Second through hole 41 Spacer 42 nuts 43 Connector terminals 44 Housing 50 Shielding plate 60 Power Modules 100 Power converter 200 Circuit board sub-assemblies 201 Handabe 202 Area surrounded by the first fastening member

Claims

1. A circuit board electrically connected to a power module that drives the motor, A conductive housing for housing the circuit board, A connector for connecting to external devices, A plurality of first fastening members for fastening the connector to the circuit board, The connector and the circuit board are fastened together to the housing by a plurality of second fastening members, The connector has connector terminals that are electrically connected to the circuit board, The plurality of the first fastening members are arranged on the circuit board so as to surround the area where the connector terminals are connected. The plurality of the aforementioned second fastening members are conductive and fasten together the connector, the circuit board, and the housing by inserting them through the first through-hole formed in the circuit board and the second through-hole formed in the connector. Power converter.

2. A power conversion device according to claim 1, The second fastening member is positioned on the circuit board outside the area surrounded by the first fastening member. Power converter.

3. A power conversion device according to claim 1 or 2, The circuit board has a first ground pattern on the side facing the housing and a second ground pattern on the side opposite to the side facing the housing. The second fastening member electrically connects the second ground pattern to the housing. Power converter.

4. A power conversion device according to claim 3, A conductive spacer is provided between the circuit board and the housing, positioned inside the second through-hole. The spacer electrically connects the first ground pattern and the housing. Power converter.

5. A power conversion device according to claim 1, A shielding plate is provided between the connector and the housing. The shielding plate is fastened to the housing by the second fastening member. Power converter.

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