Power converter

Abstract

To inhibit falling of foreign objects onto a control board even if an electric power conversion device makes one revolution when assembled to a vehicle.SOLUTION: An electric power conversion device includes components, a case, a cover, and a frame. The components include a control board. The case has an opening which allows the components to be taken into the case or out of the case and houses the components. The cover covers the opening. The frame supports at least the control board of the components. The control board is arranged so as to face the cover. The frame includes a first rib for forming a labyrinth structure at an outer periphery of the control board. The cover includes a second rib for forming the labyrinth structure with the first rib.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] Patent Document 1 discloses an electronic device including a housing that houses a substrate and a connector having a lead wire electrically connected to the substrate. In order to prevent a wire from entering the housing through a gap between the housing and the connector, the electronic device has a structure using a plurality of ribs and protrusions.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When assembling a power conversion device to a vehicle, the power conversion device may be rotated once due to restrictions in the assembly process. As a result, foreign matter inside the power conversion device may fall onto a control board included in the components of the power conversion device.​​​​​​​​​​The power converter according to this disclosure comprises a component, a case, a cover, and a frame. The component includes a control board. The case has an opening that allows the component to be inserted into and removed, and houses the component. The cover covers the opening. The frame supports at least the control board among the component. The control board is positioned opposite the cover. The frame includes a first rib for forming a labyrinth structure on the outer periphery of the control board. The cover includes a second rib for forming a labyrinth structure together with the first rib. [Effects of the Invention]

[0007] According to this disclosure, even if the power converter rotates once during assembly into the vehicle, it will be possible to suppress the falling of foreign objects onto the control board. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic cross-sectional view showing the configuration of a power conversion device according to an embodiment. [Figure 2] This diagram shows the internal configuration of the power converter as seen from the direction of arrow A in Figure 1. [Modes for carrying out the invention]

[0009] Embodiments of this disclosure will be described in conjunction with the attached drawings. In each drawing, elements common to all figures are denoted by the same reference numerals, and redundant explanations are omitted or simplified.

[0010] 1. Structure Figure 1 is a schematic cross-sectional view showing the configuration of a power converter 10 according to an embodiment. The power converter 10 is mounted on a vehicle. The power converter 10 includes an inverter and drives an electric motor that rotates the wheels. In the example shown in Figure 1, the power converter 10 is configured as a single electric drive unit together with the electric motor and a reduction gear (including a differential gear). Such an electric drive unit is also called an e-Axle unit.

[0011] The power converter 10 comprises its components 20, a case 30, a cover 32, and a frame 34. The components 20, along with a control board 22 on which circuits are formed, include, for example, a power semiconductor module, a capacitor, a reactor, and a current sensor. In Figure 1, components other than the control board 22 are comprehensively and concisely represented as components 24.

[0012] Case 30 is part of the case of the electric drive unit. Case 30 houses the components 20. Case 30 has an opening 36 that allows the components 20 to be inserted into and removed from the inside of case 30. The cover 32 is formed to cover the opening 36. As shown in Figure 1, the control board 22 is positioned opposite the cover 32.

[0013] The frame 34 supports at least the control board 22 of the component 20. In the example shown in Figure 1, the frame 34 also supports the component 24. At least one of the component 24 may be supported by other support members instead of, or together with, the frame 34. The frame 34 is fixed to the case 30, for example, via support members (not shown).

[0014] When installing a power converter into a vehicle, the power converter may be rotated 360 degrees due to constraints in the assembly process. As a result, if the control board is positioned opposite the cover as shown in Figure 1, there is a risk that foreign objects inside the power converter may fall onto the control board of the power converter.

[0015] More specifically, the expected rotation direction when assembling the power converter to the vehicle is as shown in Figure 1. If the upper side of Figure 1 (the side with the cover 32) is considered vertically upward, when the power converter 10 is rotated 180° from the state shown in Figure 1, foreign matter inside the case 30 will accumulate on top of the cover 32. Then, when the power converter 10 is rotated another 180° from that rotated state back to the state shown in Figure 1, if the countermeasures described later are not taken, the foreign matter will fall onto the control board 22 facing the cover 32.

[0016] In this context, "foreign matter" refers to dust or shavings generated during the manufacturing process of components of a power conversion device (electric drive unit). For example, foreign matter is generated during the manufacturing of the aluminum case or during the assembly of the power conversion device body (for example, the assembly of component 20 and frame 34 in Figure 1). Among the foreign matter generated in this way, conductive foreign matter that falls onto the control board can cause a short circuit in the circuit formed on the control board. The size of the foreign matter is expected to be, for example, less than or equal to the pin pitch (in mm) of the components mounted on the control board.

[0017] To address the aforementioned problem (foreign objects falling onto the control board), the power converter 10 according to this embodiment is equipped with the following countermeasures. These countermeasures will be explained below with additional reference to Figure 2 in addition to Figure 1. Figure 2 is a view of the internal configuration of the power converter 10 from the direction of arrow A in Figure 1.

[0018] As a countermeasure to the above, the frame 34 includes a first rib 40 for forming a labyrinth structure on the outer circumference of the control board 22. The cover 32 includes a second rib 50 for forming a labyrinth structure together with the first rib 40. The first rib 40 may be integrally formed with the frame 34, or it may be a separate part fixed to the frame 34. The same applies to the relationship between the cover 32 and the second rib 50.

[0019] More specifically, the first rib 40 has a main body portion 40a formed so as to protrude from the frame 34 toward the cover 32 side. The second rib 50 is formed so as to protrude from the cover 32 toward the frame 34 side in the vicinity of the first rib 40. As shown in FIG. 1, the main body portion 40a of the first rib 40 and the second rib 50 are formed so as to overlap each other in the direction in which they protrude. The labyrinth structure is realized by the main body portion 40a and the second rib 50 formed in this way.

[0020] FIG. 2 shows an example of the installation range R of the first rib 40 and the second rib 50. The rib installation range R is set so that the ribs 40 and 50 extend along a direction parallel to the rotation axis when the power conversion device 10 rotates as shown in FIG. 1. The direction of the rotation axis is represented by a straight line B in FIG. 2. In addition, the second rib 50 is provided at a portion facing the frame 34 near the outer periphery of the control board 22, rather than at the edge of the cover 32.

[0021] Note that, instead of the example shown in FIG. 2, the rib installation range R may be formed so as to cover the entire outer periphery of the control board 22, for example. Also, as shown in FIG. 1, the second rib 50 is provided on the side farther from the control board 22 than the first rib 40. However, conversely to this example, the second rib 50 may be provided on the side closer to the control board 22 than the first rib 40.

[0022] Furthermore, as shown in FIG. 2, the first rib 40 has a flange portion 40b formed so as to protrude from the tip of the main body portion 40a toward the second rib 50 side (folded-back structure). In addition, it is desirable that the length L of the flange portion 40b is longer than the diameter of an assumed foreign object. Instead of the flange portion 40b, a flange portion similar to the flange portion 40b may be formed on the second rib 50 so as to protrude toward the first rib 40 side.

[0023] 2. Effects As described above, the power conversion device 10 according to the present embodiment includes a labyrinth structure formed using the first rib 40 (main body portion 40a) and the second rib 50 on the outer periphery of the control board 22. Thereby, even if the power conversion device 10 rotates as shown in FIG. 1 when assembled to the vehicle, foreign matter (for example, foreign matter 100 (see FIG. 1) that tries to move in the direction C along with the rotation) can be prevented from entering the space existing between the cover 32 and the control board 22. Thus, according to the power conversion device 𝑙0, even if the power conversion device 10 rotates once when assembled to the vehicle, it is possible to suppress the fall of foreign matter onto the control board 22.

[0024] Also, as a synergistic effect, the formation of the first rib 40 and the second rib 50 also contributes to improving the rigidity of the respective components (that is, the cover 32 and the frame 34) used for forming the labyrinth structure.

[0025] Furthermore, the first rib 40 also has a flange portion 40b (folded-back structure). Thereby, it is possible to more effectively prevent the intrusion of foreign matter into the space during the rotation.

[0026] In addition, when the power conversion device is provided as a part of the electric drive unit, there are the following two examples of the orientation of the power conversion device with respect to the electric drive unit. That is, one is an example in which the power conversion device is arranged with the control board extending in the horizontal direction like the control board 22 in the example shown in FIG. 1. The other is an example in which the power conversion device is arranged with the control board extending in the vertical direction. According to the countermeasures according to the present embodiment, it is possible to prevent the mixing of foreign matter into the control board in both of these examples.

Explanation of Reference Numerals

[0027] 10 Power conversion device, 22 Control board, 30 Case, 32 Cover, 34 Frame, 36 Opening of the case, 40 First rib, 50 Second rib

Claims

1. Components including the control board, A case having an opening that allows the aforementioned components to be inserted and removed, and which houses the aforementioned components, A cover that covers the opening, At least one of the above components is a frame that supports the control board, A power conversion device comprising, The control board is positioned so as to face the cover. The frame includes a first rib for forming a labyrinth structure on the outer periphery of the control board. The cover includes a second rib for forming the labyrinth structure together with the first rib, The installation range of the first rib and the second rib is set such that the first rib and the second rib extend in a direction parallel to the axis of rotation when the power converter rotates during assembly of the power converter to the vehicle. A power conversion device characterized by the following features.

2. The first rib is A main body portion formed to protrude from the frame toward the cover side, A flange portion is formed so as to protrude from the tip of the main body toward the side of the second rib, has The power conversion device according to feature 1.

3. The second rib is A main body portion formed to protrude from the cover toward the frame side, A flange portion is formed so as to protrude from the tip of the main body toward the side of the first rib, has The power conversion device according to feature 1.

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