Power conversion device enclosure

Abstract

To provide a power conversion device enclosure in which a side cover can be attached to a frame more reliably with a simpler configuration.SOLUTION: A power conversion device enclosure includes a frame, a side cover which covers the sides of the frame, and a plurality of screws which attach the side cover to the frame, and the frame includes a plurality of female threaded portions which respectively thread into the male threaded portions of the plurality of screws, and the side cover includes an inner surface, an outer surface facing opposite to the inner surface, a plurality of recesses provided on the outer surface, and a plurality of through holes respectively extending from the inner bottom surface of the plurality of recesses towards the inner surface, and the plurality of recesses are capable of accommodating the heads of a plurality of screws inside.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] SUMMARY OF THE INVENTION An embodiment of the present invention relates to a housing for a power converter. [Background technology]

[0002] The power conversion device includes a converter that converts power and a housing that houses the converter in its internal space. By housing the converter in its internal space, the housing protects the converter from dust, external forces, etc. The housing includes a frame and side covers that cover the sides of the frame. The side covers are attached to the frame with a number of screws.

[0003] To accommodate increased capacity, power converters are often arranged side by side in a so-called parallel panel configuration. For this reason, the side covers of the power converter housings are countersunk, and the side covers are attached to the frame with flat head screws. This prevents the screw heads from protruding beyond the surface of the side covers, and prevents gaps from forming between adjacent power converters when they are arranged side by side.

[0004] However, when attaching the side cover to the frame with flat head screws, the female threads on the frame must be precisely aligned with the tapered screw holes (through holes) in the side cover because the screws are received on tapered surfaces, which requires high machining precision for the frame and side cover, which increases the manufacturing costs of the frame and side cover.

[0005] Furthermore, when the side covers are attached to the frame with flat head screws, the screws are received on a tapered surface, which can loosen due to vibrations during transport. This raises concerns that this will increase the amount of work required at the power conversion equipment installation site.

[0006] Therefore, in a housing for a power conversion device, it is desirable to be able to more reliably attach the side cover to the frame with a simpler configuration while preventing gaps from forming between adjacent power conversion devices when they are arranged side by side. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 2022-79937 [Patent Document 2] Patent No. 7046263 Summary of the Invention [Problem to be solved by the invention]

[0008] An embodiment of the present invention provides a housing for a power conversion device that can more reliably attach side covers to a frame with a simpler configuration while preventing gaps from forming between adjacent power conversion devices when they are installed side by side. [Means for solving the problem]

[0009] According to an embodiment of the present invention, there is provided a housing for a power conversion device, which is used in a power conversion device, has an internal space, and houses a converter that converts electric power within the internal space, the housing comprising: a frame; a side cover that covers a side of the frame; and a plurality of screws that attach the side cover to the frame, each of the plurality of screws having a male thread portion and a head portion provided at one end of the male thread portion and having a diameter larger than that of the male thread portion, the head portion having a planar contact surface facing the male thread portion side, the frame having a plurality of female thread portions that are provided corresponding to each of the plurality of screws and that screw into the male thread portions of each of the plurality of screws, the side cover having an inner side surface that faces the internal space side and an outer side surface that faces the opposite side to the inner side, a plurality of recesses that are provided corresponding to each of the plurality of female thread portions of the frame and are positioned in alignment with each of the plurality of female thread portions, and that are provided on the outer side so as to be recessed from the outer side surface toward the inner side surface, and have a planar inner bottom surface, and the plurality of recesses and a plurality of through holes provided corresponding to each recess, extending from the inner bottom surface of each of the plurality of recesses toward the inner side surface, connecting the inner bottom surface and the inner side surface, exposing each of the plurality of female threaded portions of the frame to the outer side surface, and allowing the male threaded portions of the plurality of screws to be inserted therethrough, thereby allowing the plurality of screws to be attached to the plurality of female threaded portions from the outer side surface, wherein the plurality of recesses are capable of accommodating the heads when the male threaded portions of the plurality of screws are inserted into the plurality of through holes and screwed into the plurality of female threaded portions of the frame, and the side cover is provided with a housing for a power conversion device that is attached to the frame by the plurality of screws by inserting the male threaded portions of the plurality of screws into the plurality of through holes and screwing the male threaded portions of the plurality of screws into the plurality of through holes and bringing the planar inner bottom surface into contact with the planar contact surface of the head. [Effects of the Invention]

[0010] According to an embodiment of the present invention, a housing for a power conversion device is provided that can more reliably attach side covers to a frame with a simpler configuration while preventing gaps from forming between adjacent power conversion devices when the devices are installed side by side. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 2 is a perspective view schematically illustrating a housing for a power conversion device according to an embodiment. [Figure 2] FIG. 2 is a perspective view schematically illustrating a housing for a power conversion device according to an embodiment. [Figure 3] 3(a) and 3(b) are cross-sectional views schematically illustrating a part of a housing for a power converter according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] Each embodiment will be described below with reference to the drawings. The drawings are schematic or conceptual, and the relationship between the thickness and width of each part, the size ratio between parts, etc. are not necessarily the same as those in reality. Furthermore, even when the same part is shown, the dimensions and ratios may be different depending on the drawing. In the present specification and the drawings, elements similar to those described above with reference to the previous drawings are designated by the same reference numerals, and detailed descriptions thereof will be omitted as appropriate.

[0013] 1 and 2 are perspective views that schematically show a housing for a power converter according to an embodiment. 1 and 2, a housing 10 for a power conversion device includes a frame 12, a side cover 14, and a plurality of screws 16. Note that Fig. 1 shows a state in which the side cover 14 is attached to the frame 12. For convenience, Fig. 2 shows a state in which the side cover 14 has been removed from the frame 12 (a state before the side cover 14 is attached to the frame 12).

[0014] The housing 10 is used in a power conversion device. The housing 10 has an internal space IS, and a converter (not shown) that converts power is housed within the internal space IS. This allows the housing 10 to protect the converter from, for example, dust and external forces. The housing 10 is not limited to housing only the converter, and may also house a transformer, a switch, etc. within the internal space IS. It is sufficient that the housing 10 is configured to be able to house at least the converter within the internal space IS.

[0015] Furthermore, the housing 10 is compatible with a side-by-side panel configuration in which multiple power conversion devices are arranged side by side (in the left-right direction). Therefore, both the left and right side surfaces of the housing 10 are configured as substantially parallel flat surfaces. This makes it possible to arrange multiple power conversion devices (multiple housings 10) side by side. For example, by arranging two adjacent housings 10 with their sides in contact with each other, it is possible to prevent gaps from being created between the two adjacent housings 10.

[0016] The frame 12 has, for example, a plurality of support columns that form the framework of the housing 10. In other words, the frame 12 is formed of a plurality of support columns. The frame 12 supports the side cover 14 and other components with a plurality of support columns. This allows the frame 12 to form an internal space IS surrounded by the side cover 14 and other components. The frame 12 also supports, for example, a converter and other components housed in the internal space IS with a plurality of support columns. The outer shape of the frame 12 is, for example, rectangular (cuboid). In other words, the outer shape of the housing 10 is, for example, rectangular. However, the shape of the frame 12 is not limited thereto, and may be any shape that can appropriately house the converters and other components of the power conversion device and that can accommodate a side-by-side panel configuration of multiple power conversion devices.

[0017] The side cover 14 covers the side of the frame 12. In other words, the side cover 14 is attached to the side of the frame 12 to cover the side of the internal space IS. The side cover 14 is, for example, in the shape of a substantially rectangular plate that matches the side shape of the substantially rectangular frame 12. However, the shape of the side cover 14 is not limited to this and may be any shape that can cover the side of the frame 12.

[0018] In this example, one side of the frame 12 is covered by one side cover 14. For example, one side of the frame 12 may be covered by multiple side covers 14. In other words, the side cover 14 may be divided into multiple members. The shape of the side cover 14 may be any shape that can cover at least a portion of the side of the frame 12.

[0019] The housing 10 includes, for example, a pair of side covers 14 that cover both sides of the frame 12. The housing 10 also includes, for example, a door that can open and close and cover the front of the frame 12, a back cover that covers the back of the frame 12, and a top cover that covers the top of the frame 12. This covers the periphery of the internal space IS and appropriately protects the converter and other components provided within the internal space IS. However, the configuration of the housing 10 may be any configuration that includes at least the frame 12 and one side cover 14. For example, the top and back of the internal space IS may be covered by air conditioning equipment that conditions the air within the internal space IS.

[0020] The plurality of screws 16 attach the side cover 14 to the frame 12. In other words, the plurality of screws 16 are holding members for holding the side cover 14 to the frame 12. In this example, the side cover 14 is attached to the frame 12 by four screws 16 arranged near the four corners of the roughly plate-shaped side cover 14. However, the arrangement and number of the plurality of screws 16 are not limited to this, and any arrangement and number may be used as long as the side cover 14 can be appropriately attached to the frame 12.

[0021] 3(a) and 3(b) are cross-sectional views schematically illustrating a part of a housing for a power converter according to an embodiment. 3(a) and 3(b) show enlarged views of the configuration of the mounting portions of the screws 16 on the frame 12 and the side cover 14. Also, Fig. 3(a) shows the state before the screws 16 are mounted on the frame 12 and the side cover 14, and Fig. 3(b) shows the state after the screws 16 have been mounted on the frame 12 and the side cover 14.

[0022] As shown in FIGS. 3(a) and 3(b), each of the multiple screws 16 has a male thread portion 16a and a head portion 16b provided at one end of the male thread portion 16a and having a diameter larger than that of the male thread portion 16a. The head portion 16b has a planar contact surface 16c facing the male thread portion 16a. More specifically, the contact surface 16c is a plane perpendicular to the direction (axial direction) in which the male thread portion 16a extends. Note that the contact surface 16c is not limited to being a perfect plane and may have irregularities (surface roughness) within a margin of error. Furthermore, the contact surface 16c does not need to be perfectly perpendicular to the direction in which the male thread portion 16a extends and may have errors.

[0023] The multiple screws 16 are, for example, low-head screws with heads 16b thinner than normal screws. The thickness of the heads 16b (the length in the direction of extension of the male thread portion 16a) is, for example, 1.0 mm or more and 1.5 mm or less. In other words, low-head screws are screws with heads 16b having a thickness of 1.0 mm or more and 1.5 mm or less.

[0024] The frame 12 has a plurality of female thread portions 12a that are provided corresponding to the plurality of screws 16 and that screw into the respective male thread portions 16a of the plurality of screws 16. As shown in Fig. 2, in this example, the frame 12 has four female thread portions 12a that correspond to the four screws 16, respectively. The four female thread portions 12a are arranged, for example, near the four corners of a side surface portion of the substantially rectangular frame 12, corresponding to the four screws 16, respectively.

[0025] The side cover 14 has an inner surface 14a facing the internal space IS and an outer surface 14b facing the opposite side to the inner surface 14a. In other words, the outer surface 14b is the surface facing outward (the surface exposed to the outside).

[0026] The side cover 14 also has a plurality of recesses 20 and a plurality of through holes 22. The recesses 20 are provided corresponding to the plurality of female thread portions 12a of the frame 12, respectively. In other words, the recesses 20 are provided corresponding to the plurality of screws 16, respectively. The recesses 20 are arranged so as to align with the plurality of female thread portions 12a of the frame 12, respectively. When the side cover 14 is arranged in an appropriate mounting position on the frame 12, the recesses 20 are arranged so as to overlap with the plurality of female thread portions 12a of the frame 12, respectively, when viewed from the side (viewed from a direction perpendicular to the outer surface 14b).

[0027] The plurality of recesses 20 are provided on the outer surface 14b so as to recess from the outer surface 14b toward the inner surface 14a. The plurality of recesses 20 have a planar inner bottom surface 20a that is substantially parallel to the outer surface 14b. Note that the inner bottom surface 20a is not limited to being a perfect plane, and may have irregularities (surface roughness) to the extent of a margin of error. Furthermore, the inner bottom surface 20a does not need to be perfectly parallel to the outer surface 14b, and may have an error or the like.

[0028] The plurality of through holes 22 are provided corresponding to the plurality of recesses 20, respectively. The plurality of through holes 22 extend from the inner bottom surface 20a of each of the plurality of recesses 20 toward the inner side surface 14a, connecting the inner bottom surface 20a and the inner side surface 14a. The plurality of through holes 22 are also arranged so as to face the plurality of female thread portions 12a of the frame 12, respectively, when the side cover 14 is placed in an appropriate attachment position relative to the frame 12. As a result, the plurality of through holes 22 expose the plurality of female thread portions 12a of the frame 12 to the outer side surface 14b.

[0029] The width of the multiple through holes 22 is set to be equal to or greater than the diameter of the male thread portions 16a of the multiple screws 16 and less than the diameter of the heads 16b. In other words, the width of the multiple through holes 22 is the length of the through holes 22 in a direction parallel to the outer surface 14b. The shape of the multiple through holes 22 when viewed from the side is, for example, circular. In this case, the diameter of the multiple through holes 22 is set to be equal to or greater than the diameter of the male thread portions 16a of the multiple screws 16 and less than the diameter of the heads 16b. As a result, the multiple through holes 22 allow the male thread portions 16a of the multiple screws 16 to pass through while preventing the heads 16b from passing through.

[0030] In this way, the multiple through holes 22 expose each of the multiple female thread portions 12a of the frame 12 to the outer surface 14b side and allow the male thread portions 16a of the multiple screws 16 to be inserted therethrough, thereby allowing the multiple screws 16 to be attached to the multiple female thread portions 12a of the frame 12 from the outer surface 14b side. Note that the shape of the multiple through holes 22 as viewed from the side is not limited to a circular shape and may be any shape. The shape of the multiple through holes 22 may be any shape that allows the male thread portions 16a of the multiple screws 16 to be inserted therethrough while preventing the heads 16b from being inserted therethrough.

[0031] The shapes of the plurality of recesses 20 are formed to correspond to the shapes of the heads 16b of the plurality of screws 16. The plurality of recesses 20 are capable of accommodating the heads 16b when the male threaded portions 16a of the plurality of screws 16 are inserted into the plurality of through holes 22 and screwed into the plurality of female threaded portions 12a of the frame 12.

[0032] The width of the recesses 20 is set to be equal to or larger than the diameter of the heads 16b of the screws 16. The shape of the recesses 20 as viewed from the side is, for example, circular. In this case, the diameter of the recesses 20 is set to be equal to or larger than the diameter of the heads 16b of the screws 16.

[0033] The depth of the recesses 20 is set to be equal to or greater than the thickness of the heads 16b of the screws 16. In other words, the depth of the recesses 20 is the length of the recesses 20 in a direction perpendicular to the outer surface 14b.

[0034] In this way, the width of the multiple recesses 20 is set to be equal to or greater than the diameter of the heads 16b of the multiple screws 16, and the depth of the multiple recesses 20 is set to be equal to or greater than the thickness of the heads 16b of the multiple screws 16. As described above, the thickness of the heads 16b is, for example, 1.0 mm or more and 1.5 mm or less. The thickness of the side cover 14 is, for example, 2.0 mm or more and 4.0 mm or less. The depth of the multiple recesses 20 is set to be equal to or slightly greater than the thickness of the heads 16b. This allows the heads 16b to be accommodated inside the recesses 20. The multiple recesses 20 may be called, for example, countersunk holes. The shape of the multiple recesses 20 is not limited to the above and may be any shape that can accommodate the heads 16b.

[0035] 3(b), when the male thread portions 16a of the multiple screws 16 are inserted into the multiple through holes 22 and the male thread portions 16a of the multiple screws 16 are screwed into the multiple female thread portions 12a of the frame 12, the multiple recesses 20 accommodate the heads 16b inside and bring the planar inner bottom surface 20a into contact with the planar contact surface 16c of the heads 16b. In this way, part of the side cover 14 is sandwiched between the heads 16b of the multiple screws 16 and the frame 12, and the side cover 14 can be attached to the frame 12 by the multiple screws 16.

[0036] The multiple through holes 22 have a predetermined dimensional tolerance with respect to the diameter of the male thread portions 16a of the multiple screws 16 and the diameter of the multiple female thread portions 12a of the frame 12, and the width of the multiple through holes 22 is formed to be larger than the diameter of the male thread portions 16a of the multiple screws 16 and the diameter of the multiple female thread portions 12a of the frame 12 by the amount of the dimensional tolerance.

[0037] The recesses 20 have a predetermined dimensional tolerance with respect to the diameter of the heads 16b of the screws 16, and the width of the recesses 20 is formed to be larger by the dimensional tolerance than the diameter of the heads 16b of the screws 16. Furthermore, the dimensional tolerance of the recesses 20 with respect to the diameter of the heads 16b of the screws 16 is set to be larger than the dimensional tolerance of the through holes 22 with respect to the diameter of the male thread portions 16a of the screws 16 and the diameter of the female thread portions 12a of the frame 12.

[0038] As described above, in the housing 10 for the power conversion device of this embodiment, the side cover 14 exposes each of the multiple female threaded portions 12a of the frame 12 on the outer surface 14b side and has multiple through holes 22 that allow the male threaded portions 16a of the multiple screws 16 to be inserted therethrough, thereby allowing the multiple screws 16 to be attached to the multiple female threaded portions 12a of the frame 12 from the outer surface 14b side, and also has multiple recesses 20 that allow the heads 16b to be accommodated inside when the male threaded portions 16a of the multiple screws 16 are inserted into the multiple through holes 22 and screwed into the multiple female threaded portions 12a of the frame 12.

[0039] In this way, by accommodating the heads 16b of the multiple screws 16 in the multiple recesses 20 of the side cover 14, it is possible to prevent the heads 16b from protruding beyond the outer surface 14b of the side cover 14. Therefore, even when multiple power conversion devices are arranged side by side, it is possible to appropriately prevent gaps from being created between adjacent power conversion devices. For example, even when multiple housings 10 are arranged side by side, it is possible to prevent the heads 16b of the screws 16 in two adjacent housings 10 from coming into contact with each other, which would result in a relatively large gap being created between the side covers 14 of the two adjacent housings 10.

[0040] Furthermore, in the housing 10, the side cover 14 is attached to the frame 12 by the plurality of screws 16, with the male thread portions 16a of the plurality of screws 16 inserted into the plurality of through holes 22, the male thread portions 16a of the plurality of screws 16 threadedly engaging the plurality of female thread portions 12a of the frame 12, and the flat inner bottom surface 20a contacting the flat contact surface 16c of the head 16b. This makes it possible to prevent the plurality of screws 16 from loosening due to vibrations during transportation, compared to a configuration in which flat head screws are used and received by a tapered surface. This makes it possible to prevent an increase in the amount of work at the installation site and an increase in costs that accompanies the increase in work.

[0041] Furthermore, compared to a configuration in which flat head screws are used and received on a tapered surface, the housing 10 reduces the need for high processing precision in manufacturing the frame 12 and the side cover 14. As described above, the housing 10 allows the recesses 20 to have a dimensional tolerance for the diameter of the heads 16b of the screws 16, and allows the through holes 22 to have a dimensional tolerance for the diameter of the male thread portions 16a of the screws 16 and the diameter of the female thread portions 12a of the frame 12. This makes it easier to manufacture the frame 12 and the side cover 14 and reduces increases in manufacturing costs compared to a configuration in which flat head screws are used.

[0042] In a configuration using flat head screws, high processing precision is required for the frame and side covers, which may require the frame and side covers to be manufactured by the same manufacturer. In contrast, the housing 10 according to this embodiment reduces the need for high processing precision in the manufacture of the frame 12 and side covers 14, and it is possible to outsource the manufacture of the frame 12 and side covers 14 to different manufacturers. This also makes it possible, for example, to obtain competitive bids from multiple manufacturers for each of the frame 12 and side covers 14, which can further reduce manufacturing costs.

[0043] In this way, according to the housing 10 for the power conversion device of this embodiment, when the devices are arranged side by side, gaps between adjacent power conversion devices can be prevented, and the side covers can be attached to the frame more reliably with a simpler configuration.

[0044] For example, the dimensional tolerance for the diameter of the heads 16b of the screws 16 in the recesses 20 is set to be larger than the dimensional tolerance for the diameter of the male thread portions 16a of the screws 16 in the through holes 22 and the diameter of the female thread portions 12a of the frame 12. This makes it possible to more appropriately suppress the need for high processing precision in the manufacture of the frame 12 and the side cover 14. This makes it easier to manufacture the frame 12 and the side cover 14, and more appropriately suppresses increases in manufacturing costs.

[0045] The present embodiment includes the following aspects. (Appendix 1) A housing for a power conversion device, which is used in a power conversion device, has an internal space, and houses a converter that converts power in the internal space, The frame and side covers that cover the sides of the frame; a plurality of screws that attach the side cover to the frame; Equipped with Each of the plurality of screws is A male thread portion, a head portion provided at one end of the male screw portion and having a diameter larger than that of the male screw portion; and The head portion has a flat contact surface facing the male screw portion, the frame has a plurality of female thread portions provided corresponding to the plurality of screws and threadably engaging with the male thread portions of the plurality of screws, The side cover is an inner surface facing the internal space; an outer surface facing opposite the inner surface; a plurality of recesses provided in the outer surface so as to correspond to the plurality of female screw portions of the frame, positioned in alignment with the plurality of female screw portions, recessed from the outer surface toward the inner surface, and having a planar inner bottom surface; a plurality of through holes provided corresponding to the plurality of recesses, extending from the inner bottom surface of each of the plurality of recesses toward the inner side surface, communicating the inner bottom surface with the inner side surface, exposing each of the plurality of female screw portions of the frame to the outer side surface, and allowing the male screw portions of the plurality of screws to be inserted therethrough, thereby allowing the plurality of screws to be attached to the plurality of female screw portions from the outer side surface; and the plurality of recesses are capable of accommodating the heads therein when the male threaded portions of the plurality of screws are inserted into the plurality of through holes and the male threaded portions of the plurality of screws are screwed into the plurality of female threaded portions of the frame, The side cover is a housing for a power conversion device that is attached to the frame by the plurality of screws by inserting the male threaded portions of the plurality of screws into the plurality of through holes, screwing the male threaded portions of the plurality of screws into the plurality of female threaded portions of the frame, and contacting the planar inner bottom surface with the planar contact surface of the head.

[0046] (Appendix 2) widths of the plurality of through holes are larger than diameters of the male thread portions of the plurality of screws and diameters of the plurality of female thread portions of the frame by a predetermined dimensional tolerance; 2. A housing for a power conversion device according to claim 1, wherein widths of the recesses are larger than diameters of the heads of the screws by a predetermined dimensional tolerance.

[0047] (Appendix 3) 3. A housing for a power conversion device as described in Appendix 2, wherein the dimensional tolerance for diameters of the heads of the plurality of screws in the plurality of recesses is greater than the dimensional tolerance for diameters of the male thread portions of the plurality of screws in the plurality of through holes and the dimensional tolerance for diameters of the plurality of female thread portions of the frame.

[0048] (Appendix 4) 4. The housing for a power converter according to claim 1, wherein the thickness of the heads of the plurality of screws is 1.0 mm or more and 1.5 mm or less.

[0049] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0050] 10...housing, 12...frame, 12a...female thread portion, 14...side cover, 14a...inner surface, 14b...outer surface, 16...screw, 16a...male thread portion, 16b...head, 16c...contact surface, 20...recess, 20a...inner bottom surface, 22...through hole, IS...internal space

Claims

1. A housing for a power conversion device, which is used in a power conversion device, has an internal space, and houses a converter that converts power in the internal space, The frame and side covers that cover the sides of the frame; a plurality of screws that attach the side cover to the frame; Equipped with Each of the plurality of screws is A male thread portion, a head portion provided at one end of the male screw portion and having a diameter larger than that of the male screw portion; and The head portion has a flat contact surface facing the male screw portion, the frame has a plurality of female thread portions provided corresponding to the plurality of screws and threadably engaging with the male thread portions of the plurality of screws, The side cover is an inner surface facing the internal space; an outer surface facing opposite the inner surface; a plurality of recesses provided in the outer surface so as to be recessed from the outer surface toward the inner surface, the recesses having a planar inner bottom surface, the recesses being provided in correspondence with the plurality of female screw portions of the frame and aligned with the plurality of female screw portions; a plurality of through holes provided corresponding to the plurality of recesses, extending from the inner bottom surface of each of the plurality of recesses toward the inner side surface, communicating the inner bottom surface with the inner side surface, exposing each of the plurality of female screw portions of the frame to the outer side surface, and allowing the male screw portions of the plurality of screws to be inserted therethrough, thereby allowing the plurality of screws to be attached to the plurality of female screw portions from the outer side surface; and the plurality of recesses are capable of accommodating the heads therein when the male threaded portions of the plurality of screws are inserted into the plurality of through holes and the male threaded portions of the plurality of screws are screwed into the plurality of female threaded portions of the frame, The side cover is a housing for a power conversion device that is attached to the frame by the plurality of screws by inserting the male threaded portions of the plurality of screws into the plurality of through holes, screwing the male threaded portions of the plurality of screws into the plurality of female threaded portions of the frame, and contacting the planar inner bottom surface with the planar contact surface of the head.

2. widths of the plurality of through holes are larger than diameters of the male thread portions of the plurality of screws and diameters of the plurality of female thread portions of the frame by a predetermined dimensional tolerance; 2. The power converter housing according to claim 1, wherein widths of the recesses are larger than diameters of the heads of the screws by a predetermined dimensional tolerance.

3. 3. The housing for a power conversion device according to claim 2, wherein the dimensional tolerance for the diameters of the heads of the plurality of screws in the plurality of recesses is greater than the dimensional tolerance for the diameters of the male thread portions of the plurality of screws in the plurality of through holes and the diameters of the plurality of female thread portions of the frame.

4. 2. The power converter housing according to claim 1, wherein the thickness of the heads of the plurality of screws is 1.0 mm or more and 1.5 mm or less.

Images