JP2004312925A - Electrical equipment having electric circuit and circuit element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To miniaturize an inverter device having a capacitor element. <P>SOLUTION: An inverter unit 100 includes a capacitor housing 110, an inverter case 120, a heat sink 130, the capacitor element 112, a capacitor bus bar 114, an inverter input bus bar 116, a molded resin 118, an inverter control substrate 122, a bus bar fastening bolt 124, a nut 126, a power semiconductor 128, and a waterproof cap 132. The capacitor element 112 is mounted to the inside of the capacitor housing 110 by the molded resin 118. The end part of the inverter input bus bar 116 is bent vertically. The end part and the capacitor bus bar 114 are fastened by the bus bar fastening bolt 124 and the nut 126. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electric device having an electric circuit and a circuit element connected to the electric circuit, and more particularly to an electric device having an inverter and a capacitor element connected to the inverter.
[0002]
[Prior art]
Conventionally, the following is disclosed as an inverter unit storing a capacitor element and an inverter.
[0003]
Referring to FIG. 7, an inverter unit storing a capacitor element by a conventional method will be described. FIG. 7 is a cross-sectional view of an inverter unit 200 having a conventional structure.
[0004]
The inverter unit 200 includes a cover 202, an inverter case 204, a capacitor housing 206, a capacitor element 208, a mold resin 210, a capacitor bus bar 212, an inverter input bus bar 214, a bus bar fastening bolt 216, and a heat sink 218. An inverter circuit (not shown) is attached to the inverter input bus bar 214.
[0005]
The capacitor element 208 is fixed to the capacitor housing 206 by a mold resin 210. The capacitor bus bar 212 and the inverter input bus bar 214 are fastened by bus bar fastening bolts 216. Capacitor bus bar 212 is bent at a right angle so that its surface matches the upper surface of inverter input bus bar 214. Thereby, workability at the time of attaching the bus bar fastening bolt 216 can be improved.
[0006]
However, according to the structure shown in FIG. 7, since the upper part of the bus bar fastening bolt 216 becomes a wasted space, there is a limit to the miniaturization of the inverter unit.
[0007]
To solve such a problem, Japanese Patent Laying-Open No. 2000-152656 (Patent Document 1) discloses a small power conversion device having a smoothing capacitor. Referring to FIG. 8, power conversion device 300 includes power conversion unit 302, flat capacitor 304 having a pair of wide side surfaces to reduce voltage fluctuation, and power conversion unit 302 and flat capacitor 304. The case 306, 308 to be stored, at least one pair of sandwiching members 310 that are in close contact with at least central portions in the axial direction and the circumferential direction of the pair of wide side surfaces of the flat type capacitor, and regulate expansion thereof, a substrate 312, and an input. A terminal 314 and connection members 316 and 318 are included. The power conversion unit 302 and the flat type capacitor 304 are connected by the input terminal 314 of the capacitor and the connection members 316 and 318.
[0008]
According to this power conversion device, the height of the cases 306 and 308 can be reduced by using the flat type capacitor 304 as the smoothing capacitor. As a result, the height shape of the power converter can also be reduced.
[0009]
[Patent Document 1]
JP 2000-152656 A (FIG. 2)
[0010]
[Problems to be solved by the invention]
However, according to the power converter disclosed in Patent Literature 1, although the height direction can be reduced by the flat type capacitor 304, the axial direction (that is, the horizontal direction) is not shortened. There was a problem that can not be converted.
[0011]
Generally, when the power converter is in operation, the temperature of the power converter rises because the connection between the capacitor and the electric circuit generates heat due to charging and discharging of the capacitor. At this time, the degree of temperature rise differs depending on the position in the power conversion device, which may affect the temperature characteristics of the device.
[0012]
The present invention has been made in order to solve the above-described problems, and has as its object to reduce the size of the entire device, reduce the number of components, and further suppress changes in temperature characteristics. It is to provide.
[0013]
[Means for Solving the Problems]
An electric device according to a first aspect of the present invention is an electric device that includes an electric circuit, a circuit element connected to the electric circuit, a housing that stores the circuit element, and a case that stores the electric circuit, the circuit element, and the housing. is there. In this electric device, a circuit element and an electric circuit are cut off from the outside by integrating a housing and a case.
[0014]
According to the first invention, the housing for storing the circuit element and the case for storing the circuit element and the electric circuit are integrated, so that the circuit element and the electric circuit are cut off (protected) from the outside (for example, The opening of the case can be closed while storing the circuit element). This eliminates the need for a member that only closes the opening of the case, thereby reducing the number of components of the electric device. Further, since the space for such members can be reduced, the size of the electric device can be reduced. Thus, it is possible to provide an electric device in which the overall size is reduced and the number of components is reduced.
[0015]
According to a second aspect of the present invention, in addition to the configuration of the first aspect, the electric device further includes an electric circuit bus bar provided in the electric circuit, a circuit element bus bar provided in the circuit element, the electric circuit bus bar and the circuit element bus bar. And a fixing member for fixing. The case is provided with an opening through which the fastening member passes. The electric circuit bus bar and the circuit element bus bar are fixed by a fixing member via the opening.
[0016]
According to the second aspect, by fixing the electric circuit bus bar and the circuit element bus bar through the opening using the fixing member, the electric circuit and the circuit element can be fastened. In this case, it is not necessary to provide a work space (space) for fastening inside the case, so that the size of the electric device can be reduced without impairing the workability.
[0017]
An electric device according to a third aspect of the invention has a plurality of electric circuit bus bars and circuit element bus bars in addition to the configuration of the second aspect of the invention. The plurality of electric circuit bus bars and the circuit element bus bars are fixed at a plurality of fixing portions by a fixing member.
[0018]
According to the third aspect, since the electric circuit bus bar and the circuit element bus bar are fixed at the plurality of fixing portions, heat generated during operation of the electric device can be distributed to the respective fixing portions. With this configuration, a difference in temperature distribution between the electric device and a circuit element (for example, an inverter unit) is reduced, so that a change in temperature characteristics of the electric device can be prevented. Further, since the distance from each connection portion to the circuit element is shorter than the distance when one fixed portion is provided, the inductance of each circuit can be reduced. Thereby, the loss in the circuit element can be reduced.
[0019]
In the electric device according to a fourth aspect, in addition to the configuration of the third aspect, the plurality of fixing portions are provided so as to be symmetric with respect to the center of the electric device.
[0020]
According to the fourth aspect, since the bias of the temperature distribution in the electric device is suppressed, a local temperature change can be prevented.
[0021]
An electric device according to a fifth aspect of the invention further includes a seal member in addition to the configuration of any of the second to fourth aspects of the invention. The seal member is attached to the opening.
[0022]
According to the fifth aspect, the waterproofness at the opening of the case can be improved by the seal member (for example, the waterproof cap, the waterproof putty, etc.).
[0023]
An electric device according to a sixth aspect further includes a resin member in addition to the configuration of any one of the first to fifth aspects. The circuit element is attached to the housing by a resin member.
[0024]
According to the sixth aspect, since the circuit element and the housing are insulated from each other, the electric device can be operated stably.
[0025]
An electric device according to a seventh aspect of the present invention is the electric device according to any one of the first to sixth aspects, wherein the electric circuit is an inverter circuit, and the circuit element is a capacitor.
[0026]
According to the seventh aspect, since the opening of the case for storing the inverter circuit is sealed by the housing of the capacitor, the number of parts of the electric device including the inverter circuit and the capacitor can be reduced, and the size can be reduced.
[0027]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same components are denoted by the same reference numerals. Their names and functions are the same. Therefore, detailed description thereof will not be repeated.
[0028]
<First embodiment>
With reference to FIG. 1, the configuration of the inverter unit 100 according to the first embodiment of the present invention will be described. FIG. 1 is a vertical sectional view of the inverter unit 100.
[0029]
The inverter unit 100 includes a capacitor housing 110, an inverter case 120, a heat sink 130, a capacitor element 112, a capacitor bus bar 114, an inverter input bus bar 116, a molding resin 118, an inverter control board 122, a bus bar fastening bolt. 124, a nut 126, a power semiconductor 128, and a waterproof cap 132. The mold resin 118 is a resin having an insulating property.
[0030]
The capacitor element 112 is mounted inside the capacitor housing 110 by a mold resin 118. Therefore, the capacitor element 112 and the capacitor housing 110 are insulated.
[0031]
A capacitor bus bar 114 is attached to an end of the capacitor element 112. This mounting method is not particularly limited, and may be any method that ensures conduction between the capacitor element 112 and the capacitor bus bar 114 (for example, welding).
[0032]
The inverter case 120 is attached to the heat sink 130. As shown in FIG. 1, an opening 134 for attaching a busbar fastening bolt 124 from outside is formed on a side surface of the inverter case 120.
[0033]
An inverter control board 122 is attached to the inverter input bus bar 116. The end of the inverter input bus bar 116 is bent in the vertical direction. The end and the end of the capacitor busbar 114 are fastened by busbar fastening bolts 124 and nuts 126. The inverter input bus bar 116 is supported by a support member (not shown) so as not to contact the power semiconductor 128 due to the weight of the inverter control board 122.
[0034]
With this mounting, conduction between the capacitor element 112 and the inverter control board 122 can be ensured.
[0035]
The connection portion between capacitor housing 110 and inverter case 120 is joined, for example, by welding. Thus, even when acceleration occurs in inverter unit 100 due to vibration, capacitor housing 110 and inverter case 120 can maintain a connected state without being separated.
[0036]
The power semiconductor 128 is attached to the heat sink 130. Thereby, heat generated from the power semiconductor 128 is radiated through the heat sink 130, so that a rise in the temperature of the inverter unit 100 can be prevented. Note that a heat conductive grease such as silicon grease may be applied to a gap generated between the power semiconductor 128 and the heat sink 130. Thereby, the heat radiation effect can be further improved.
[0037]
The waterproof cap 132 is attached from outside the bus bar fastening bolt 124 to waterproof the inverter unit 100.
[0038]
As described above, according to the inverter unit 100 according to the first embodiment of the present invention, the busbar fastening bolt 124 for attaching the capacitor busbar 114 and the inverter input busbar 116 can be externally fastened. Further, there is no need to provide a space inside the inverter unit 100 for mounting the capacitor bus bar 114 and the inverter input bus bar 116.
[0039]
Thus, it is possible to prevent a decrease in workability at the time of fastening the busbar fastening bolt 124 and to reduce the size of the inverter unit 100.
[0040]
The capacitor housing 110 functions as a cover for the inverter case 120. Further, the capacitor housing 110 and the inverter case 120 are joined by welding. The capacitor bus bar 114 and the inverter input bus bar 116 are fastened by bolts. Note that the capacitor housing 110 and the inverter case 120 may be fastened by bolts.
[0041]
By joining the capacitor housing 110 and the inverter case 120 by welding, a cover for closing the opening of the inverter case 120 or a flange for attaching the capacitor housing 110 is not required, so that the cost for parts of the inverter unit 100 is reduced. can do. Thus, it is possible to provide an inverter unit that can reduce the number of parts and further reduce the size without impairing workability for assembly.
[0042]
<Second embodiment>
Hereinafter, a second embodiment of the present invention will be described with reference to FIGS.
[0043]
Referring to FIG. 2, a configuration of inverter unit 400 according to the present embodiment will be described. FIG. 2 is a vertical sectional view of the inverter unit 400.
[0044]
The inverter unit 400 includes a capacitor housing 410, an inverter case 420, a heat sink 430, a capacitor element 412, a capacitor bus bar 414, an inverter input bus bar 416, a molding resin 418, an inverter control board 422, a bus bar fastening bolt. 424, a nut 426, a power semiconductor 428, and a waterproof cap 432.
[0045]
Inverter case 420 has openings 434 on each side surface (a total of four surfaces). The capacitor bus bar 414 and the inverter input bus bar 416 are provided at four locations corresponding to each opening, as described later. The capacitor bus bar 414 includes a positive bus bar and a negative bus bar.
[0046]
Inverter unit 400 is different from inverter unit 100 (FIG. 1) in the number of openings 434, capacitor bus bars 414, and inverter input bus bars 416, but is otherwise the same. Therefore, description thereof will not be repeated.
[0047]
With reference to FIG. 3, a configuration of a connection portion with inverter control board 422 in inverter unit 400 according to the present embodiment will be described. FIG. 3 is a diagram showing a mounting portion of the capacitor element 412 shown in FIG. 2 as viewed from the X direction.
[0048]
The capacitor element 412 is disposed between the capacitor element mounting plates 440 and 442. Four negative electrode bus bars 414b are attached to the capacitor element attachment plate 440. Four positive bus bars 414a are mounted on the capacitor element mounting plate 442. These busbars are connected to busbars (not shown) attached to inverter control board 422 (FIG. 2).
[0049]
Referring to FIG. 4, the arrangement of positive bus bar 414a and negative bus bar 414b in inverter unit 400 according to the present embodiment will be described. FIG. 4 is a diagram showing the capacitor mounting plate 440 shown in FIG. 3 from the Y direction.
[0050]
The positive bus bar 414a and the negative bus bar 414b are disposed at point-symmetric positions on the capacitor element mounting plate 442. With this configuration, when the inverter unit 400 operates, the capacitor element 412 is charged and discharged via each connection portion. Therefore, when the temperature of the capacitor element 412 changes, the bias of the temperature change is reduced. Thereby, a change in the operation characteristics of inverter unit 400 can be suppressed.
[0051]
The arrangement of the bus bars is not limited to this, and may be an arrangement that is not symmetric. Further, the number of connection portions is not limited to four, and may be increased or decreased due to space restrictions of the inverter unit 400 or the like.
[0052]
The temperature distribution of the capacitor element included in the inverter unit will be described with reference to FIGS. FIG. 5 is a diagram showing a temperature distribution in each capacitor element 412 of inverter unit 400 according to the present embodiment. FIG. 6 is a diagram showing a temperature distribution in a capacitor element of a conventional inverter unit. In each figure, curves (A), (B) and (C) represent isothermal curves.
[0053]
The magnitude relation of the temperature of the capacitor element 412 in FIG. 5 is such that the curve (B) <the curve (A) or the curve (B) <the curve (C). In this case, for example, the temperature difference (ΔT) between capacitor element 412a and capacitor element 412c is relatively small.
[0054]
On the other hand, the magnitude relation of the temperature of the capacitor element 812 in FIG. 6 is as follows: Curve (C) <Curve (B) <Curve (A). In this case, for example, the temperature difference between capacitor element 812a and capacitor element 812c is larger than the temperature difference (ΔT) in the case of FIG.
[0055]
As described above, in the inverter unit having the conventional connection structure, the temperature distribution of the capacitor element 812 depends on the position of the positive bus bar 814a. The temperature is higher than the temperature of the capacitor element located away from 814a. Therefore, by connecting the capacitor element and the inverter at a plurality of locations, it is possible to prevent the influence of temperature rise due to charging and discharging of the capacitor element from being concentrated on a specific capacitor.
[0056]
As described above, according to inverter unit 400 according to the present embodiment, a plurality of positive electrode bus bars 414a and negative electrode bus bars 414b are provided on capacitor element mounting plate 440 such that the positions of connection with inverter control board 422 are symmetrical. ing. As a result, the charge / discharge current of the capacitor element can be dispersed, so that only a specific capacitor element does not become hot. Thereby, local temperature rise of inverter unit 400 can be prevented. Further, a change in the temperature characteristics of the inverter unit 400 can be suppressed.
[0057]
The embodiments disclosed this time are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.
[Brief description of the drawings]
FIG. 1 is a sectional view of an inverter unit according to a first embodiment of the present invention.
FIG. 2 is a sectional view of an inverter unit according to a second embodiment of the present invention.
FIG. 3 is a diagram (part 1) illustrating a mounting portion of a capacitor element in the inverter unit illustrated in FIG. 2;
FIG. 4 is a diagram (part 2) illustrating a mounting portion of the capacitor element in the inverter unit illustrated in FIG. 2;
5 is a diagram showing a temperature distribution in a capacitor element of the inverter unit shown in FIG.
FIG. 6 is a diagram showing a temperature distribution in a capacitor element of a conventional inverter unit.
FIG. 7 is a sectional view (part 1) of a conventional inverter unit.
FIG. 8 is a sectional view (part 2) of a conventional inverter unit.
[Explanation of symbols]
100 Inverter unit, 112,412 Capacitor element, 114,414 Capacitor bus bar, 414a, 814a Positive bus bar, 414b Negative bus bar, 116,416 Inverter bus bar, 118,418 Mold resin, 120,420 Inverter case, 122,422 Inverter control board , 124,424 bus bar fastening bolt, 126,426 nut, 128,428 power semiconductor, 130,430 heat sink, 132,432 waterproof cap, 440,442 capacitor element mounting plate, 814 bus bar.

Claims (7)

An electric device having an electric circuit, a circuit element connected to the electric circuit, a housing for storing the circuit element, and a case for storing the electric circuit, the circuit element, and the housing,
An electric device in which the housing and the case are integrated to cut off the circuit element and the electric circuit from the outside. The electric device includes:
An electric circuit bus bar provided in the electric circuit,
A circuit element bus bar provided on the circuit element;
The electric circuit bus bar further includes a fixing member for fixing the circuit element bus bar,
The case is provided with an opening through which the fastening member passes,
The electric device according to claim 1, wherein the electric circuit bus bar and the circuit element bus bar are fixed by the fixing member via the opening. The electric device has a plurality of the electric circuit bus bar and the circuit element bus bar,
The electric device according to claim 2, wherein the plurality of electric circuit busbars and the circuit element busbar are fixed by the fixing member at a plurality of fixing portions. The electric device according to claim 3, wherein the plurality of fixing portions are provided so as to be symmetric with respect to a center of the electric device. The electric device further includes a seal member,
The electric device according to claim 2, wherein the seal member is attached to the opening. The electric device further includes a resin member,
The electric device according to claim 1, wherein the circuit element is attached to the housing with the resin member. The electric circuit is an inverter circuit,
The electric device according to claim 1, wherein the circuit element is a capacitor.

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