Power control unit

Abstract

To provide a technology of inhibiting a switching noise generated in a PCU from propagating to the outside, and resisting an external force which is applied to the PCU case when a vehicle collision occurs.SOLUTION: A PCU includes a lid part, a case, and a connection terminal. A printed circuit board is housed in the case. Electronic components mounted on the printed circuit board include an electronic component having a switching function. The case has a wall portion. A terminal for connecting the printed circuit board to the outside is mounted on the wall portion. The wall portion has a branch wall branching from the wall portion toward the interior of the case. The branch point of the branch wall is located between a position where the electronic component having a switching function is mounted and a position where the terminal is mounted on the wall portion.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure relates to the structure of a case of a power control unit (PCU) applied to a vehicle.

Background Art

[0002] Japanese Unexamined Patent Application Publication No. 2020-010469 discloses the structure of a PCU mounted on a plug-in hybrid vehicle. This conventional PCU includes a lower case and an upper case stacked on the lower case. An ACDC converter for converting AC power from a commercial power supply into DC power is provided in the lower case. On the other hand, a filter circuit is provided in the upper case. The filter circuit filters noise (switching noise) generated by the switching circuit of the ACDC converter. According to the filtering, it is possible to suppress the propagation of the switching noise to the input side (that is, the commercial power supply side) of the ACDC converter.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the conventional PCU was not developed from the perspective of suppressing the propagation of switching noise to the output side of the AC-DC converter. Therefore, there is a possibility that the high-frequency component of the switching noise propagates inside the lower case and reaches the outside of the PCU. The conventional PCU was also not developed from the perspective of suppressing damage to the power supply system elements of the PCU when the PCU case is damaged during a vehicle collision. Therefore, when an external force is applied to the ceiling plate of the upper case or the bottom plate of the lower case during a vehicle collision, the ceiling plate or the bottom plate may be damaged without being able to resist it.

[0005] One object of the present disclosure is to provide a technology capable of suppressing the propagation of switching noise generated in the PCU to the outside of the PCU and resisting an external force applied to the PCU case during a vehicle collision.

Means for Solving the Problems

[0006] The present disclosure is a PCU including a printed circuit board on which electronic components are mounted and a case that houses the printed circuit board, and has the following features. The case includes a mounting portion, a wall portion, and a lid portion. The printed circuit board is fixed to the mounting portion. The wall portion rises from the surface of the mounting portion where the printed circuit board is mounted and surrounds the outer periphery of the printed circuit board. The lid portion faces the mounting surface of the printed circuit board in the mounting portion and is in contact with the end surface of the wall portion. The electronic components include electronic components having a switching function. Terminals for connecting the printed circuit board to the outside are attached to the wall portion. The wall portion includes a branch wall that branches from the wall portion and extends toward the inside of the case. The branching location of the branch wall from the wall portion is located between the position where the electronic component having the switching function is mounted and the position where the terminal is attached to the wall portion.

[0007] In the present disclosure, the branch wall may include a first part and a second part. The first part may extend from the branch point toward the central part of the case. The second part may extend in a direction orthogonal to the first part and away from the mounting position of the electronic component having the switching function.

[0008] In the present disclosure, the lid part may have a branch wall receiving part. The branch wall receiving part may rise from the surface facing the mounting surface and contact the end face of the branch wall.

[0009] In the present disclosure, the printed circuit board may have a cutout part. The cutout part may be provided in a region corresponding to the position where the branch wall is provided.

Advantages of the Invention

[0010] According to the present disclosure, a branch wall that branches from the wall part constituting the case and extends toward the inside of the case is provided on the wall part. According to the branch wall, it becomes possible to strengthen the durability of the case in the standing direction of the branch wall. Further, the branch point of the branch part from the wall part is located between the position where the electronic component having the switching function is mounted and the position where the terminal is attached to the wall part. Therefore, it becomes possible to block the propagation of the high-frequency component of the switching noise generated from the electronic component having the switching function with the branch wall. Accordingly, it is also possible to suppress the propagation of the high-frequency component to the outside of the PCU through the terminal attached to the wall part.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Mode for Carrying Out the Invention

[0012] Hereinafter, with reference to the drawings, a PCU according to an embodiment of the present disclosure will be described. In each figure, the same or corresponding parts are denoted by the same reference numerals, and the description thereof is simplified or omitted.

[0013] 1. Layout Example of Engine Compartment FIG. 1 is a diagram for explaining a layout example of an engine compartment in which a PCU according to an embodiment is mounted. The engine compartment 1 shown in FIG. 1 is for a hybrid vehicle or a plug-in hybrid vehicle (hereinafter, also referred to as "HEV vehicle") having an engine and a motor as drive sources, and an engine 2, a radiator 3, and a PCU 4 are housed therein. The engine 2 is provided at the center of the engine compartment 1, and the radiator 3 is provided in front (FR) of this.

[0014] The PCU according to the embodiment is the PCU 4 provided on the right side (RG) of the engine 2. The PCU 4 is mounted in the engine compartment 1, for example, as a relay box connected to an accessory battery. Note that the right side (RG), left side (LF), and rear side (RR) shown in FIG. 1 are based on the front (FR) of the HEV vehicle.

[0015] FIG. 2 is a view of a cross section when the engine compartment 1 is cut along line A-A shown in FIG. 1, as seen from the radiator 3 side. Although various components other than the engine 2 and the PCU 4 are housed in the engine compartment 1, these components are omitted from FIG. 2 for the sake of convenience in explanation. Similar to FIG. 1, the right side (RG) and the left side (LF) shown in FIG. 2 are based on the front (FR) of the HEV vehicle.

[0016] As shown in FIG. 2, the engine 2 includes an engine body 21 and a buffer plate 22. The buffer plate 22 has a function of guiding the PCU 4 along the surface of the buffer plate 22 when a collision occurs from the right side of the HEV vehicle and the PCU 4 moves to the left side (LF). According to the buffer plate 22, it is possible to minimize damage to the PCU 4 by the engine 2 and damage to the engine 2 by the PCU 4 during a collision from the right side of the HEV vehicle.

[0017] 2. Configuration Example of PCU FIGS. 3 to 5 are diagrams for explaining a configuration example of the PCU according to the embodiment. FIG. 3 corresponds to a view of the PCU 4 as seen from the lid portion 41 side, FIG. 4 corresponds to a view showing the inside of the PCU 4 when the lid portion 41 is removed, and FIG. 5 corresponds to a view showing the back surface of the lid portion 41. Similar to FIG. 1, the right side (RG), the left side (LF), and the rear side (RR) shown in FIGS. 3 to 5 are based on the front (FR) of the HEV vehicle.

[0018] As shown in FIGS. 3 and 4, the PCU 4 includes a lid portion 41, a case 42, and connection terminals 43. The lid portion 41 is screwed to the case 42 and constitutes a PCU case together with the case 42. The lid portion 41 and the case 42 are formed by casting a metal material having a magnetic shield such as aluminum and a high thermal conductivity, for example. A printed circuit board PB is housed in the case 42. Various electronic components E1 to E8 are mounted on the printed circuit board PB. Examples of the electronic components E1 to E8 include passive components such as resistors and capacitors, and active components such as transistors, relays, and diodes. The transistors include MOSFETs having a switching function, and the electronic component E8 shown in FIG. 4 corresponds to this.

[0019] The connection terminal 43 is a terminal for connecting the printed circuit board PB to the outside. The connection terminal 43 is connected to various auxiliary devices such as, for example, a car navigation system, power windows, brakes, and door locks.

[0020] As shown in FIG. 4, the case 42 has a wall portion 44. The wall portion 44 is provided so as to rise from the surface (hereinafter also referred to as the "mounting surface") 45 on which the printed circuit board PB is mounted. The wall portion 44 has a wall main body 44a and an end face 44b. The wall main body 44a surrounds the periphery of the printed circuit board PB, and thereby, the printed circuit board PB is housed in the case 42. The end face 44b contacts the back surface of the lid portion 41 described in FIG. 5.

[0021] The wall portion 44 also has a branch wall 44c having a substantially L-shaped and an end face 44d. The branch wall 44c has the same height as the height of the wall main body 44a. The end face 44d contacts the back surface of the lid portion 41 described in FIG. 5.

[0022] Specifically, the branch wall 44c branches in the middle of the wall portion 44 and extends toward the inside of the case 42. The location where the branch wall 44c branches from the wall portion 44 is located between the position where the electronic component E8 is mounted on the printed circuit board PB and the position where the connection terminal 43 is attached. The branch wall 44c also bends in the middle and extends in a direction away from the mounting position of the electronic component E8. The portion of the branch wall 44c extending in the front-rear direction of the HEV vehicle corresponds to the "first part" in the present disclosure, and the portion thereof extending in the front-rear direction of the HEV vehicle corresponds to the "second part" in the present disclosure.

[0023] Since the branch wall 44c is provided on the mounting surface 45, the region of the printed circuit board PB corresponding to the position where the branch wall 44c is provided is cut out. This cutout region CT corresponds to the "cutout portion" in the present disclosure.

[0024] The back surface of the lid portion 41 shown in FIG. 5 has a surface 41a (hereinafter also referred to as the "opposing surface") that faces the attachment surface 45 described in FIG. 4. On the opposing surface 41a, receiving portions 41b and 41c are provided so as to rise therefrom. These receiving portions have the same height. The receiving portion 41b is aligned with the end surface 44b described in FIG. 4. The receiving portion 41b corresponds to the "wall receiving portion" in the present disclosure. On the other hand, the receiving portion 41c is aligned with the end surface 44d described in FIG. 4. The receiving portion 41c corresponds to the "branch wall receiving portion" in the present disclosure.

[0025] 3. Effects FIGS. 6 and 7 are diagrams for explaining the first effect of the PCU according to the embodiment. FIG. 6 is a scene simulating the occurrence of a collision from the right side of the HEV vehicle. In this figure, the HEV vehicle is colliding with a pole on the right side of the HEV vehicle. FIG. 7 is a diagram showing the results of a CAE (Computer Aided Engineering) analysis in the scene shown in FIG. 6. FIG. 7 shows the cross-sections of the HEV vehicle before the collision (0 msec) and immediately after the collision (30 and 45 msec), and this cross-section is at the same position as the cross-section described in FIG. 2.

[0026] As understood from the two types of results immediately after the collision shown in FIG. 7, when a collision occurs from the right side of the HEV vehicle, the PCU 4 moves to the left (LF) (30 msec). When the PCU 4 contacts the buffer plate 22, the PCU 4 moves along the surface of the buffer plate 22 (45 sec). At this time, the central portion of the lid portion 41 is distorted upward (UP) by the impact energy, and further, when a large amount of impact energy is applied, the entire lid portion 41 is distorted upward. Then, there is a possibility that the distorted lid portion 41 interferes with the printed circuit board PB and impairs various functions of the PCU 4.

[0027] In this regard, according to the PCU according to the embodiment, since the branch wall 44c is provided, the durability of the PCU case in the vertical direction is enhanced. Therefore, when a collision occurs from the right side of the HEV vehicle, it is possible to suppress the lid portion 41 from being greatly distorted by contact with the buffer plate 22.

[0028] Also, according to the PCU according to the embodiment, the branch wall 44c has a substantially L-shaped configuration. Therefore, compared with the case where a branch wall having a linear shape is provided, the durability of the PCU case in the vertical direction can be enhanced. Also, according to the PCU according to the embodiment, the receiving portion 41c is provided on the lid portion 41. Therefore, by aligning the receiving portion 41c with the end face 44d, it is possible to surely enhance the durability of the PCU case in the vertical direction by the branch wall 44c.

[0029] FIG. 8 is a diagram for explaining a second effect of the PCU according to the embodiment. As already described, the electronic component E8 has a switching function. Therefore, there is a possibility that high-frequency components of switching noise propagate inside the PCU case. In this regard, according to the PCU according to the embodiment, a branch wall 44c is provided between the position where the electronic component E8 is mounted and the position where the connection terminal 43 is attached. Therefore, it is possible to block the propagation of high-frequency components inside the PCU case here. Accordingly, it is also possible to suppress the propagation of high-frequency components to the outside of the PCU 4 via the connection terminal 3.

[0030] 4. Modifications In the embodiment described above, an example of the wall portion 44 to which the branch wall 44c having a substantially L-shaped configuration is added has been described. However, the shape of the branch wall applicable to the present disclosure is not limited to this, and for example, a substantially C-shaped configuration, a substantially T-shaped configuration, or a linear shape may be used. In any modification, if there is a branch portion of the branch wall at a position between the position where the electronic component E8 is mounted and the position where the connection terminal 3 is attached, an effect equivalent to that of the branch wall 44c having a substantially L-shaped configuration is expected.

Description of Reference Numerals

[0031] 1 Engine Compartment 2 Engine 21 Engine Body 22 Buffer Plate 3 Radiator 4 Power Control Unit (PCU) 41 Cover part 41a Opposite surface 41b, 41c Receiving part 42 Case 43 Connection terminal 44 Wall part 44a Wall body 44b, 44d End face 44c Branch wall 45 Mounting surface CT Notch area E1 - E8 Electronic components PB Printed circuit board

Claims

1. A power control unit that includes a printed circuit board on which electronic components are mounted and a case that houses the printed circuit board, and is housed in an engine compartment of a hybrid vehicle having an engine and a motor as drive sources, wherein the case includes an attachment portion to which the printed circuit board is fixed, a wall portion that rises from a surface of the attachment portion on which the printed circuit board is mounted and surrounds an outer periphery of the printed circuit board, and a lid portion that faces a mounting surface of the printed circuit board in the attachment portion and is in contact with an end surface of the wall portion, the electronic components include electronic components having a switching function, terminals for connecting the printed circuit board to the outside are attached to the wall portion, the wall portion includes a branch wall that branches from the wall portion and extends toward the inside of the case, a branching portion of the branch wall from the wall portion is located between a position where an electronic component having a switching function is mounted and a position where the terminal is attached to the wall portion, the branch wall includes a first portion that extends from the branching portion toward a central portion of the case and a second portion that extends in a direction orthogonal to the first portion and toward a position where the terminal is attached to the wall portion away from a mounting position of the electronic component having a switching function, characterized in that it is a power control unit.

2. The lid portion has a branch wall receiving portion that rises from a surface facing the mounting surface and is in contact with an end surface of the branch wall, characterized in that it is the power control unit according to claim 1.

3. The printed circuit board has a cutout portion provided in a region corresponding to a position where the branch wall is provided, characterized in that it is the power control unit according to claim 1 or 2.

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