JP2018191388A - Power conversion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power conversion device capable of attaining reduction of cost by easily dealing with a design change.SOLUTION: A power conversion device comprises: a circuit board; electrical components which are mounted on the circuit board; a heat sink with which a component mounting part where the electrical components are mounted, and a heat radiation part which radiates heat generated by the electrical components are formed integrally; a box-shaped casing in which the heat sink and the electrical components are accommodated; and a seal member which is interposed between the heat sink and the casing. The casing consists of a separate member from the heat sink. The heat sink is fitted to the casing in a state where the heat radiation part is exposed outside via an opening which is formed in the casing.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a power conversion device, and more particularly, to a power conversion device suitable for in-vehicle use.

  An environment-friendly vehicle such as an electric vehicle is equipped with a power converter such as a charger, an inverter, and a DC-DC converter. The power conversion device includes an electrical component such as a power semiconductor element that generates heat when energized. Usually, the electrical component is thermally connected to a heat sink (heat radiating member) for efficiently radiating generated heat to the outside. Patent Documents 1 and 2 disclose a structure in which a heat sink formed of a member different from a casing is attached to an opening formed in the casing and is thermally connected to an electrical component.

  Moreover, in a power converter, the casing is often manufactured by die casting from the viewpoint of waterproofness, heat dissipation, vibration resistance, and the like. Since die casting can be processed into a complicated shape and has high dimensional accuracy, the heat sink and the housing can be formed integrally. In Patent Documents 1 and 2, the casing and the heat sink are configured as separate members, but in this case as well, it is considered that the casing and the heat sink are each manufactured by die casting.

JP 2001-168560 A JP 2013-162017 A

  By the way, even if the vehicle type in which the power conversion device is mounted is different, the electrical circuit and electrical components housed in the power conversion device do not change significantly. However, the mounting position of the power conversion device varies depending on the vehicle type, and the required outer size and shape are different. Therefore, at least the casing of the power conversion device has been newly developed for each vehicle type.

  However, die casting requires a long time to design and manufacture a mold, and the cost of the mold is also expensive. Therefore, designing for each vehicle type leads to an increase in development cost. In addition, when the design change such as the layout of the electrical parts is performed in the development stage, the mold is remanufactured, which also increases the development cost. Thus, in the conventional power converter, since the housing is formed by die casting, it is difficult to reduce the cost.

  The objective of this invention is providing the power converter device which can respond easily to a design change and can aim at cost reduction.

The power converter according to the present invention is
A circuit board;
Electrical components mounted on the circuit board;
A heat sink formed integrally with a component placement portion on which the electrical component is placed and a heat dissipation portion that dissipates heat generated by the electrical component;
A box-shaped housing for housing the heat sink and the electrical component;
A seal member interposed between the heat sink and the housing,
The housing is configured by a member different from the heat sink,
The heat sink is attached to the casing in a state where the heat radiating portion is exposed to the outside through an opening formed in the casing.

  ADVANTAGE OF THE INVENTION According to this invention, the power converter device which can respond easily to a design change and can aim at cost reduction is provided.

1A and 1B are views showing an external appearance of a charger 1 according to an embodiment of the present invention. It is a figure which shows the state of the charger which removed the circuit board. It is the disassembled perspective view which looked at the charger from upper direction. It is the disassembled perspective view which looked at the charger from the bottom. 5A and 5B are views showing a state where an electrical component (FET) is attached to a heat sink. It is a disassembled perspective view which shows the structure of a heat sink and an electrical component (FET). It is sectional drawing of the part by which the heat sink and electrical component (FET) in a charger are arrange | positioned.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  1A and 1B are views showing an external appearance of a charger 1 according to an embodiment of the present invention. FIG. 1A is a perspective view of the charger 1 as seen from above, and FIG. 1B is a perspective view of the charger 1 as seen from below. FIG. 2 is a diagram illustrating a state of the charger 1 with the circuit board 40 removed. FIG. 3 is an exploded perspective view of the charger 1 as viewed from above. FIG. 4 is an exploded perspective view of the charger 1 as viewed from below. 3 and 4, the electrical component 41 mounted on the upper surface of the circuit board 40 and the boss 14 standing on the housing 10 are omitted.

  As shown in FIGS. 1A, 1B, 2 and 3, the charger 1 includes a housing 10, a heat sink 20, an electrical component 30, a circuit board 40, and the like.

  The circuit board 40 is a printed board on which a predetermined circuit pattern is formed. The circuit board 40 is disposed to face the bottom surface of the housing 10. Electrical components 30 and 41 are mounted on the circuit board 40. The electrical component 30 is mounted on the lower surface (surface on the housing 10 side) of the circuit board 40 for heat dissipation. The electrical component 41 includes, for example, a film capacitor and a relay. The electrical component 41 is mounted on the upper surface of the circuit board 40 because the necessity of heat dissipation is low.

  The electrical component 30 is a component that self-heats when energized. For example, a field effect transistor (FET) 30B, 30C, a diode 30D, a power semiconductor element such as a bridge diode 30E (so-called power semiconductor), a coil 30F, and the like. And a transformer 30A and the like. Standardized general-purpose products can be applied to the power semiconductor elements 30B to 30E.

  The lead part 32 of the electrical component 30 is electrically connected to a circuit pattern (not shown) of the circuit board 40 (see FIG. 5). The heat radiation surface 31a of the electrical component 30 is thermally connected to the component placement surface 21a of the heat sink 20 (see FIG. 6). An insulating sheet 54 is interposed between the power semiconductor elements 30 </ b> B to 30 </ b> D and the heat sink 20.

  The heat sink 20 is in thermal contact with the electrical component 30 and dissipates heat generated by the electrical component 30 to the outside. The heat sink 20 is provided corresponding to each of the electrical components 30A to 30F (heat sinks 20A to 20F). The heat sinks 20A to 20E corresponding to the electrical components 30A to 30E are attached to the housing 10 from the inside of the housing 10 (upper side in FIGS. 3 and 4). The heat sink 20F corresponding to the electrical component 30F is attached to the housing 10 from the outside of the housing 10 (the lower side in FIGS. 3 and 4). Note that whether the heat sink 20 is attached to the housing 10 from the inside or the outside is not particularly limited.

  The heat sink 20 is preferably formed by die casting. Thereby, even if the heat sink 20 has a complicated shape, it can be accurately manufactured. Moreover, when mass-producing the heat sink 20, cost reduction can be achieved. In addition, since a metal mold | die becomes small compared with the case where a housing | casing and a heat sink are integrally formed by die-cast shaping | molding conventionally, the cost required for die-cast shaping | molding is reduced. A specific fixing structure of the electric component 30 and the heat sink 20 will be described later.

  The housing 10 is a box-shaped member that houses the heat sink 20, the electrical component 30, and the circuit board 40. The housing 10 is formed by subjecting a metal plate (for example, a steel plate) to sheet metal processing including punching, bending, and drawing. In general, it is possible to reduce costs by performing sheet metal processing rather than die casting.

  The housing 10 includes a recessed chamber 11 that houses the electrical components 30A to 30F, the circuit board 40, and the like. A flange 12 is formed on the upper edge of the concave chamber 11 so as to project outward. A lid (not shown) having a symmetrical shape with the housing 10 is attached to the housing 10 so as to cover the opening surface of the concave chamber 11. For example, the flange 12 of the housing 10 and the flange (not shown) of the lid are overlapped and screwed to fix both.

  The housing 10 has an opening 13 on the bottom surface of the concave chamber 11. The opening 13 is provided corresponding to each of the heat sinks 20A to 20F (openings 13A to 13E). The heat radiating portion 22 (see FIG. 5) of the heat sink 20 is exposed to the outside of the housing 10 through the opening 13. On the other hand, the component placement portion (see the component placement portion 21 in FIG. 5) of the heat sink 20 on which the electrical components 30 </ b> A to 30 </ b> F are mounted is disposed inside the concave chamber 11 of the housing 10. The concave chamber 11, the flange 12 and the opening 13 can be easily formed by sheet metal processing. Since the housing 10 is formed by sheet metal processing, even if the design (for example, the size and shape of the housing 10, the position of the opening 13 (in other words, the mounting position of the electrical components 30A to 30F), etc.) is changed. Can be easily and cost-effectively.

  Further, a boss 14 having a screw hole for fixing the heat sink 20 and the like is erected on the bottom surface of the housing 10 (see FIG. 2). The boss 14 is formed on the bottom surface of the concave chamber 11 by welding, for example. Although not shown, a screw hole through which a screw (reference numeral omitted, see FIG. 1B) for fixing the heat sink 20 is inserted is formed on the bottom surface of the housing 10.

  Hereinafter, the fixing structure of the heat sink 20 and the electrical component 30 will be described by taking the electrical component 30B (FET) as an example. 5A and 5B are views showing a state in which the electrical component 30B is attached to the heat sink 20B. FIG. 6 is an exploded perspective view showing the structure of the heat sink 20B and the electrical component 30B. FIG. 7 is a cross-sectional view of a portion of the charger 1 where the heat sink 20B and the electrical component 30B are disposed. 5A, 5B, 6 and 7, the insulating sheet 54 (see FIG. 3) is omitted.

  As shown in FIG. 5A, FIG. 5B, FIG. 6 and FIG. 7, here, four electrical components 30B are juxtaposed and fixed to one heat sink 20B by a biasing member 51.

  The electrical component 30 </ b> B is a lead insertion type general-purpose transistor, and includes a package portion 31 and a lead portion 32. One main surface of the package part 31 is a heat radiating surface 31a. The lead part 32 extends from the package part 31 in a bent state, and is connected to the circuit board 40 by soldering, for example.

The heat sink 20 </ b> B includes a component placement portion 21, a heat dissipation portion 22, a fixing portion 23, a flange 24, and a groove 25.
The component mounting portion 21 has the electrical component 30 </ b> B mounted thereon and plays a role of transferring heat generated by the electrical component 30 </ b> B to the heat radiating portion 22. Moreover, the component mounting part 21 has the component mounting surface 21a in which the electrical component 30B is mounted. The component placement surface 21 a is inclined with respect to the circuit board surface of the circuit board 40. By inclining the component mounting surface 21a, the bottom area of the concave chamber 11 can be reduced as compared with the case where the component mounting surface 21a is made parallel to the substrate surface of the circuit board 40, but it may be made parallel to the substrate surface.
The heat radiating unit 22 is provided on the surface of the component mounting unit 21 opposite to the component mounting surface 21a. The heat radiating part 22 radiates heat generated by the electrical component 30B. The heat radiation part 22 has a plate-shaped heat radiation fin (reference number omitted). In addition, the shape in particular of a radiation fin is not restrict | limited, For example, a pin shape may be sufficient.

  The fixing part 23 has a positioning pin 23a and a screw hole 23b. The urging member 51 is fixed to the fixing portion 23. The flange 24 is formed to protrude outward from the component placement portion 21 and the fixing portion 23. The flange 24 is provided with a screw hole 26 for screwing to the housing 10.

  The groove 25 is provided along the outer periphery on the lower surface of the component placement portion 21, the fixing portion 23, and the flange 24, that is, the surface that contacts the housing 10. A seal member 53 (see FIG. 7) is disposed in the groove 25.

As described above, the heat sink 20B is configured to include the component mounting portion 21, the heat radiating portion 22, the fixing portion 23, the flange 24, and the groove 25 that have a complicated shape. That is, by integrating the structures that are difficult to manufacture by sheet metal processing into the heat sink 20, the casing 10 does not include a complicated structure, and the casing 10 can be formed by a low-cost manufacturing method such as sheet metal processing. Become.
The heat sink 20 can be formed by die casting. In particular, when the component mounting portion 21 and the heat dissipation portion 22 are integrally formed, higher heat transfer properties and heat dissipation properties can be realized.

  The urging member 51 has four leaf springs 51a and a connecting portion 51b that connects the leaf springs 51a. The connecting portion 51b has an insertion hole (reference numeral omitted) through which the screw 52 is inserted and an insertion hole 51c through which the positioning pin 23a of the heat sink 20B is inserted.

  The electrical component 30B is placed on the component placement portion 21 such that the heat radiating surface (not shown) of the package portion 31 is in surface contact with the component placement surface 21a. In this state, the urging member 51 is attached to the heat sink 20B. Specifically, the urging member 51 is positioned by inserting the positioning pin 23a of the heat sink 20B into the insertion hole 51c. The urging member 51 is fixed by tightening a screw 52 into the screw hole 26 of the heat sink 20B through an insertion hole (not shown). At this time, the leaf spring 51a is in a state of pressing the electrical component 30B toward the heat sink 20B. That is, the four electrical components 30B are collectively pressed and fixed to the heat sink 20B. Further, the lead portion 32 of the electrical component 30B is electrically connected to a circuit pattern (not shown) of the circuit board 40, for example, by soldering. The electrical component 30 </ b> B is mounted in a state inclined with respect to the circuit board 40.

  Since the electrical component 30B is mounted inclined with respect to the circuit board 40, the electrical component 30B can be pressed and fixed by the biasing member 51 without increasing the space between the housing 10 and the circuit board 40. At the same time, an insulation distance can be secured. Further, by pressing and fixing the electrical component 30B to the heat sink 20B, the contact thermal resistance is reduced, so that the heat dissipation efficiency is improved and the vibration resistance is also improved. Furthermore, since a standardized general-purpose product is used for the electrical component 30B, the cost can be reduced.

  The heat sink 20B is attached to the housing 10 with the heat radiating portion 22 exposed to the outside through the opening 13 formed in the housing 10 (see FIG. 7). Specifically, the heat sink 20 </ b> B is fixed to the housing 10 by tightening a screw (reference numeral: see FIG. 2) from the outside of the housing 10 in a screw hole 26 provided in the flange 24. At this time, the seal member 53 is disposed in the groove 25 of the heat sink 20B. Thereby, since the housing | casing 10 and the heat sink 20B are fixed watertight, the waterproofness of the charger 1 is ensured. An O-ring or a liquid gasket can be applied to the seal member 53.

  The structure of the heat sink 20B and the electrical component 30B has been described above as an example. However, the basic structure of the other heat sinks 20A and 20C to 20F and the electrical components 30A and 30C to 30F is the same. In the case of the heat sink 20F attached to the housing 10 from the outside, the groove 25 in which the seal member 53 is disposed is formed on the upper surface.

  As described above, the charger 1 (power conversion device) generates heat in the circuit board 40, the electrical component 30 mounted on the circuit board 40, the component placement unit 21 on which the electrical component 30 is placed, and the electrical component 30. A heat sink 20 having a heat radiating portion 22 that dissipates the heat, a box-shaped housing 10 that houses the heat sink 20 and the electrical component 30, and a seal member 53 that is interposed between the heat sink 20 and the housing 10. . The housing 10 is configured by a member different from the heat sink 20. The heat sink 20 is attached to the housing 10 with the heat radiating portion 22 exposed to the outside through the opening 13 formed in the housing 10.

  In the charger 1, the housing 10 and the heat sink 20 are configured as separate members, and the housing 10 is formed by sheet metal processing, so that required specifications (for example, external size and shape) for the charger 1 are different. However, it is only necessary to change the design of the housing 10, and the heat sink 20 can be used regardless of the design of the housing 10. In addition, even when a design change such as a layout of the electrical component 30 is performed in the development stage, it can be easily handled only by a design change of the housing 10. Therefore, according to the charger 1, it is possible to easily cope with a design change and to reduce the cost.

  In general, even if the vehicle type on which the charger 1 is mounted is different, the circuit board 40 and the electrical component 30 housed in the charger 1 are not significantly changed. Therefore, the heat sink 20 and the electrical component 30 can be expected to be shared across a plurality of vehicle types. Therefore, according to the charger 1, the expansion | deployment with respect to several vehicle types is also attained, and the further cost reduction can be achieved.

  As mentioned above, the invention made by the present inventor has been specifically described based on the embodiment. However, the present invention is not limited to the above embodiment, and can be changed without departing from the gist thereof.

  For example, the heat sink 20 may be manufactured by a manufacturing method other than die casting, and forging or extrusion molding can be applied. Further, for example, the groove for arranging the seal member 53 may be formed in the housing 10 instead of the heat sink 20.

  Further, the housing 10 may be manufactured by a manufacturing method other than sheet metal processing. For example, the housing 10 can be manufactured by resin molding.

  The embodiment disclosed this time should be considered as illustrative in all points 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.

  The power conversion device according to the present invention is suitable for a vehicle-mounted power conversion device such as a charger, an inverter, and a DC-DC converter.

1 Charger (power converter)
DESCRIPTION OF SYMBOLS 10 Case 20, 20A-20F Heat sink 21 Component mounting part 22 Heat radiation part 30, 30A-30F Electrical component 40 Circuit board 53 Seal member

Claims (8)

A circuit board;
Electrical components mounted on the circuit board;
A heat sink having a component placement portion on which the electrical component is placed and a heat dissipation portion that dissipates heat generated by the electrical component;
A box-shaped housing for housing the heat sink and the electrical component;
A seal member interposed between the heat sink and the housing,
The housing is configured by a member different from the heat sink,
The power converter, wherein the heat sink is attached to the casing in a state where the heat radiating portion is exposed to the outside through an opening formed in the casing.   The power converter according to claim 1, wherein the casing is a sheet metal processed product.   The power converter according to claim 1, wherein the casing is a resin molded product.   The power converter according to any one of claims 1 to 3, wherein the heat sink is a die cast product.   The power converter according to any one of claims 1 to 4, wherein the heat sink has a groove in which the seal member is disposed. A biasing member that presses and fixes the electrical component to the component placement unit;
The power converter according to any one of claims 1 to 5, wherein the heat sink has a fixing portion for fixing the biasing member. The biasing member is a leaf spring,
The power converter according to claim 6, wherein the fixing portion includes a positioning pin for positioning the biasing member and a screw hole for screwing the biasing member.   The power converter according to claim 1, wherein the electrical component includes a power semiconductor element that generates heat when energized.

Images