Method for assembling a power converter and power converter

Abstract

In a power conversion device equipped with a capacitor, the aim is to prevent damage to the capacitor and fixed components and to improve the ease of installation. [Solution] The fixing band 1 has a cylindrical portion 2. The cylindrical portion 2 is formed in a radial cross-section C-shape so as to embrace the side of the capacitor 6, and an opening 5 is formed in the radial direction. With one leg 3 of the fixing band temporarily fixed to the housing of the power converter with a screw, the capacitor 6 is inserted through the opening 5. All legs 3 of the fixing band are permanently fixed to the housing of the power converter with screws to fix the capacitor 6 in a state where it can move up and down. The busbars that connect to other components are screw-connected to the terminals 7 of the capacitor 6.

Description

Technical Field

[0001] The present invention relates to a fixing structure for a capacitor in a power converter. Background Art

[0002] Cylindrical electrolytic capacitors are widely used as DC smoothing capacitors for power converters such as inverters. Additionally, in many power converters, the terminals of the DC smoothing capacitor and the terminals of the semiconductor module are connected via a bus bar or the like. Prior Art Literature Patent Literature

[0003] Patent Literature 1 Japanese Unexamined Patent Publication No. 2000-60134 Summary of the Invention Problem to be Solved by the Invention

[0004] In general, electrolytic capacitors and the like have large dimensional tolerances. Therefore, when connecting capacitor terminals to a bus bar in a state where a plurality of capacitors are mounted on a flat surface such as the housing of a power converter, tolerances in height dimension may deteriorate the workability of screw fastening, and apply load to the screw portions of the capacitor terminals and fixing components such as the fixing band of the capacitor, which may lead to damage.

[0005] Patent Literature 1 is prior art that facilitates mounting of a mounting bracket (capacitor fixing band) provided on a capacitor to the housing of a power converter. However, Patent Literature 1 requires that a groove matching the shape of the capacitor fixing band be provided in the mounting portion of the housing, which results in increased cost.

[0006] For the reasons described above, in a power converter including a capacitor, it is a problem to prevent damage to the capacitor and fixing components and improve mounting workability. Means for Solving the Problem

[0007] The present invention was devised in view of the above-mentioned conventional problems, and one aspect thereof is a method for assembling a power conversion device equipped with a cylindrical capacitor, characterized in that one leg of a fixing band having a cylindrical portion formed in a radially C-shaped cross-section with a radially opening so as to embrace the side of the capacitor is temporarily fixed to the housing of the power conversion device with a screw, the capacitor is inserted through the opening, all the legs of the fixing band are permanently fixed to the housing of the power conversion device with screws to fix the capacitor in a state where it can move in the vertical direction, and a busbar for connecting to other components is screw-connected to the terminals of the capacitor.

[0008] Furthermore, in one embodiment, a power conversion device equipped with a cylindrical capacitor is provided, characterized in that it is equipped with a fixing band comprising a cylindrical portion formed in a C-shape in the radial cross-section so as to embrace the side surface of the capacitor and having an opening in the radial direction, and legs that protrude radially outward from the lower end of the cylindrical portion and are screw-fixed to the housing of the power conversion device, wherein the cylindrical portion is formed with bent portions that are folded in a mountain-fold shape at predetermined intervals in the circumferential direction and protrude radially outward.

[0009] Furthermore, in one embodiment, the cylindrical portion is characterized by having bent portions formed in a mountain-fold shape at predetermined intervals in the circumferential direction, which protrude radially outward. [Effects of the Invention]

[0010] According to the present invention, in a power conversion device equipped with a capacitor, it is possible to prevent damage to the capacitor and fixed components and improve the ease of installation. [Brief explanation of the drawing]

[0011] [Figure 1] A schematic diagram showing the fixing band of Example 1. [Figure 2] A schematic diagram showing the assembly of the capacitor in Example 1. [Figure 3] A schematic diagram showing the fixing band of Example 2. [Modes for carrying out the invention]

[0012] Examples 1 and 2 of the power conversion device equipped with a cylindrical capacitor according to the present invention and its assembly method will be described in detail below with reference to Figures 1 to 3.

[0013] [Example 1] Figure 1 shows the configuration of the fixing band 1 for securing the capacitor in this embodiment 1. Figure 1(a) is a top view, and Figure 1(b) is a perspective view. The fixing band 1 in this embodiment 1 is provided with a mechanism to absorb dimensional errors of the cylindrical capacitor.

[0014] As shown in Figure 1, the fixing band 1 has a cylindrical portion 2, leg portions 3, and support portions 4. The material of the fixing band 1 is preferably steel plate (for example, S50C-CSP) to provide the strength necessary to fix the capacitor.

[0015] The cylindrical portion 2 is formed in a C-shape in its radial cross-section so as to embrace the side surface of the capacitor, and an opening 5 is formed in the radial direction into which the capacitor is inserted.

[0016] The cylindrical portion 2 has a curved surface with a diameter slightly smaller than the diameter of the capacitor so that it can hold the capacitor. Furthermore, the relationship between the diameter of the capacitor and the diameter of the cylindrical portion 2 should preferably be such that the amount of deformation of the cylindrical portion 2 when the capacitor is inserted into the cylindrical portion 2 falls within the elastic range of the material of the fixing band 1.

[0017] The leg portion 3 is provided at the lower end of the cylindrical portion 2. The leg portion 3 is formed to protrude radially outward from the cylindrical portion 2. The leg portion 3 has a through hole through which a screw passes, and is fixed to the housing of the power converter by screw fastening.

[0018] In this embodiment 1, there are two legs 3, which are provided at predetermined intervals in the circumferential direction. In this embodiment 1, the legs 3 are provided in two locations, but there can be any number of legs 3 as long as the strength when the capacitor is mounted satisfies the desired value.

[0019] The support portion 4 is provided at the lower end of the cylindrical portion 2. The support portions 4 are provided at predetermined intervals in the circumferential direction and are provided between the leg portions 3. In the first embodiment, two support portions 4 are provided, but any number of support portions 4 may be provided as long as the strength when mounting the capacitor satisfies a desired value.

[0020] The support portion 4 protrudes radially outward from the lower end of the cylindrical portion 2. When the fixing band 1 is placed on the casing of the power conversion device, the support portion 4 is configured to come into contact with the mounting surface of the casing.

[0021] FIG. 2 shows a state when the capacitor is fixed in the first embodiment. FIG. 2(a) shows a state before the capacitor 6 is fixed to the fixing band 1, and FIG. 2(b) shows a state after the capacitor 6 is fixed to the fixing band 1.

[0022] As shown in FIG. 2(a), the capacitor 6 is inserted through the opening 5 in a state where one leg portion 3 is temporarily fixed to the casing of the power conversion device. Thereafter, all the leg portions 3 are fastened with screws (permanently fixed), thereby fixing the fixing band to the casing of the power conversion device.

[0023] The capacitor 6 is held by the frictional force between the side surface of the capacitor 6 and the cylindrical portion 2. Therefore, the capacitor 6 can be held even when the bottom surface of the capacitor 6 is floating from the casing of the power conversion device. That is, the capacitor 6 is held in a vertically movable state. Then, by connecting the capacitor terminal 7 provided on the upper surface of the capacitor 6 to a bus bar, the vertical movement of the capacitor 6 is restricted, and the capacitor 6 is fixed. Therefore, even when the capacitor 6 has a dimensional tolerance in the height direction, the capacitor 6 can be fixed to the casing of the power conversion device without applying a load to the capacitor terminal 7 connected by the bus bar, the fixing band 1, or peripheral components of the capacitor 6 (other components such as semiconductor modules).

[0024] This makes it possible to suppress mechanical damage to the capacitor 6 and fixing components, and improve the workability of mounting the capacitor 6.

[0025] Furthermore, since there is no need to provide grooves that match the shape of the fixing band, as in Patent Document 1, costs can be reduced.

[0026] Furthermore, since the cylindrical portion 2 of the fixing band 1 can be deformed in the direction of increasing diameter, this embodiment 1, although not to the same extent as embodiment 2 described later, can hold the capacitor 6 with the fixing band 1 even if the capacitor 6 has dimensional tolerances in the diameter direction.

[0027] [Example 2] Figure 3 shows the configuration of the fixing band 1 in this embodiment 2. The same reference numerals are used for parts that are the same as in Figure 1, and their descriptions are omitted. The cylindrical portion 2 of this embodiment 2 is folded in a mountain-fold shape at predetermined intervals in the circumferential direction, forming bent portions 8 that protrude radially outward. That is, the bent portions 8 of the cylindrical portion 2 are formed in a bellows shape.

[0028] In this embodiment 2, the cylindrical portion 2 deforms so that the curved surface deforms and the bent portion 8 opens. As a result, the amount of deformation in the elastic range increases compared to the deformation of only the curved surface in embodiment 1, and it becomes possible to mount capacitors 6 with larger dimensional tolerances in the diametrical direction.

[0029] In this embodiment 2, the support portion 4 protrudes circumferentially from the lower end of the bent portion 8. In this embodiment 2 as well, the support portion 4 may be provided so as to protrude radially outward from the lower end of the curved surface of the cylindrical portion 2.

[0030] The radial length of the bent portion 8 should preferably be less than or equal to the radial length of the leg portion 3 so as not to increase the dimensions during mounting. However, by extending the length of the bent portion 8, the amount of deformation in the elastic range can be increased, making it applicable to capacitors 6 with larger diametrical dimensional tolerances.

[0031] As described above, this embodiment 2 provides the same effects as embodiment 1. Furthermore, because the bent portion 8 is formed in the cylindrical portion 2, the amount of deformation in the elastic range is increased compared to embodiment 1, making it applicable to capacitors with large dimensional tolerances in the diametrical direction.

[0032] Furthermore, the bent portion 8 functions as a cooling fin, which is expected to help suppress the temperature rise of the capacitor.

[0033] Although the present invention has been described in detail only with respect to the specific examples described above, it will be obvious to those skilled in the art that a wide variety of modifications and alterations are possible within the scope of the technical concept of the present invention, and it is natural that such modifications and alterations fall within the scope of the claims. [Explanation of symbols]

[0034] 1... Fixing band, 2... Cylindrical part, 3... Leg part, 4... Indicator part, 5... Opening, 6... Capacitor, 7... Terminal, 8... Bent part

Claims

1. A method for assembling a power conversion device equipped with a cylindrical capacitor, With one leg of the fixing band, which has a cylindrical portion formed in a radial C-shape with a radial opening so as to embrace the side of the capacitor, temporarily fastened to the housing of the power converter with a screw, the capacitor is inserted through the opening. The legs of the fixing band at all locations are secured to the housing of the power converter with screws, thereby fixing the capacitor in a state where it can move vertically. A method for assembling a power conversion device, characterized by screw-connecting a busbar, which connects to other components, to the terminals of the capacitor.

2. A power conversion device equipped with a cylindrical capacitor, A cylindrical portion formed with a radially C-shaped cross-section and a radially opening to embrace the side surface of the capacitor, A leg portion that protrudes radially outward from the lower end of the cylindrical portion and is screw-fixed to the housing of the power converter, Equipped with a fixing band, The power conversion device is characterized in that the cylindrical portion has bent portions formed thereon, which are folded in a mountain-fold shape at predetermined intervals in the circumferential direction and protrude radially outward.

3. The assembly method for a power conversion device according to claim 1, characterized in that the cylindrical portion has bent portions formed thereon that are folded in a mountain-fold shape at predetermined intervals in the circumferential direction and protrude radially outward.

Images