JP4924797B2 - Automotive DC / DC converter - Google Patents

Description

The present invention relates to a vehicle DC / DC converter equipped with an AC / DC conversion module board for use in applications such as hybrid vehicles, in particular the output of what about 1～2KW.

  In applications such as hybrid vehicles, a DC / DC converter is used for the purpose of converting a high-voltage DC voltage into a low-voltage DC voltage. In this case, since a large current flows on the low voltage side compared to the high voltage side, a transformer structure that takes heat dissipation into consideration is required.

  The following Patent Document 1 shows a conventional transformer structure of an in-vehicle DC / DC converter having an output of 1 to 2 kW. Patent Document 2 below shows an example of an in-vehicle DC / DC converter.

JP 2004-303857 A JP 2002-369528 A

  Patent Document 1 is a transformer structure of an in-vehicle DC / DC converter with an output of 1 to 2 kW. The primary and secondary coils are fixed using a bobbin, and the secondary coil is fixed using a screw. The structure is coupled to the provided rectifying unit.

  Patent Document 2 is an in-vehicle DC / DC converter. A path of a secondary side large current is formed by a bus bar, and a connection between the secondary side coil and the rectifying unit is a screw connection.

  In the prior art disclosed in Patent Documents 1 and 2, since screw fastening is used for path connection between the transformer and the rectifying unit, the number of parts increases and the number of assembly steps also increases. In addition, since the primary and secondary coils of the transformer use a bobbin or have a molded structure, man-hours are required even when disassembling (disassembly may be necessary when a defect is found).

In view of the above problems, without the use of screws to the transformer secondary coil connected, also by a structure in which consideration to heat radiation of the secondary coil, miniaturization, parts and assembly Realizes an AC / DC conversion module board that can reduce man-hours, has good decomposability, and has a good heat dissipation effect. By mounting the AC / DC conversion module board, it is possible to reduce the size, the number of parts, and the number of assembly steps. It is an object of the present invention to provide an in-vehicle DC / DC converter capable of reducing the above.

  Other objects and novel features of the present invention will be clarified in embodiments described later.

In order to achieve the above object, an in- vehicle DC / DC converter according to the present invention includes:
An AC / DC conversion module board comprising: a transformer having a primary side coil and a secondary side coil; a rectifying element that rectifies an induced voltage of the secondary side coil; and a metal board .
The magnetic core of the transformer is mounted on the metal substrate with a fixture,
Having said secondary coil plurality of coil conductor portions is soldered to the conductor pattern end of each coil conductor portion is formed via an insulating layer on the metal substrate, wherein the primary coil Is inserted between the plurality of coil conductor portions ,
The plurality of coil conductor portions have a bus bar structure in which flat plate-like portions opposed to each other with the primary side coil interposed therebetween are formed, and the coil conductor portions are rectified into one of the conductor patterns soldered to the end portions of the coil conductor portions. The elements are connected by soldering,
The metal substrate of the AC / DC conversion module substrate is fixed to the heat radiating base plate in a face-to-face contact state .

In the on- vehicle DC / DC converter , the magnetic core of the transformer includes a central leg portion disposed inside the primary side coil and the secondary side coil, and an outer leg portion disposed outside the coil. a first core having may Tsu Do and a plate-shaped second core.

In the on- vehicle DC / DC converter , the magnetic core of the transformer includes a central leg portion disposed inside the primary side coil and the secondary side coil, and an outer leg portion disposed outside the coil. The first core is assembled from the upper side of the metal substrate, and the second core is assembled from the lower side of the metal substrate through a punched hole formed in the metal substrate. The lower surface of the second core may be supported by the heat radiating base plate .

The on-vehicle DC / DC converter, the switching circuits to be connected before Symbol primary coil, and the AC / DC conversion module substrate may be separately example Bei on the heat radiating base plate.

According to the on- vehicle DC / DC converter of the present invention, the secondary coil of the transformer is fixed to the conductor pattern on the metal substrate by soldering, and the connection between the secondary coil and the rectifying unit is also soldered. Since the assembly structure is performed, it is possible to reduce the size, reduce the number of parts, and reduce the number of assembly steps. In addition, the primary side coil is inserted between the secondary side coil conductors, which is bobbin-less and has good assembling and disassembling properties. Further, since the secondary coil is of the metal substrate which is fixed by soldering is cooled effectively functions as a heat radiator has a configuration of attaching further the metal substrate on the radiating base plate directly, a large current The flowing secondary coil can be installed on the heat radiating base plate with a small thermal resistance, so that the heat radiation effect is large and the secondary coil can be miniaturized, and heat is radiated from other secondary circuit parts such as the rectifier. The effect can be improved .

  Hereinafter, as the best mode for carrying out the present invention, embodiments of an AC / DC conversion module substrate and an in-vehicle DC / DC converter will be described with reference to the drawings.

  A first embodiment of the AC / DC conversion module substrate and the in-vehicle DC / DC converter will be described with reference to FIGS.

  FIG. 1 is a perspective view showing the structure of an in-vehicle DC / DC converter, FIG. 2 is a circuit diagram thereof, and an AC / DC conversion module substrate 1 is a primary coil 10 and a secondary coil 20 in the circuit diagram of FIG. And a rectifying unit including a plurality of rectifying elements 30 are mounted on a metal substrate 40, and the in-vehicle DC / DC converter 2 is AC / DC converted on a heat-dissipating base plate 3 made of a metal conductor. The module substrate 1 is directly attached and fixed. In other words, the metal substrate 40 of the AC / DC conversion module substrate 1 is in contact with the base plate 3 and is screwed thereto. On the base plate 3, a switching circuit board 5 on which the switching circuit 4 shown in the circuit diagram of FIG. 2 is mounted and a choke coil 6 connected to the secondary side of the transformer T1 are installed.

  As shown in FIGS. 3 to 6, the transformer T1 used in the AC / DC conversion module substrate 1 includes a primary side coil 10, a secondary side coil 20, an E type ferrite core 15 and an I type ferrite core constituting a magnetic core. 16 and a core fixture 17. The core fixture 17 is made of metal having elasticity, for example. The E-type ferrite core 15 has a central leg portion and outer leg portions on both sides thereof.

  The primary coil 10 is formed by forming a looped coil conductor (not shown) having a required number of turns on both surfaces of a printed circuit board 11, and a central leg portion 15 a of an E-type ferrite core 15 is formed at the center of the printed circuit board 11. A core insertion hole 12 to be inserted is formed, and the surface of the printed board 11 including the loop-shaped coil conductor is subjected to an insulation process. A primary input terminal 13 is connected to both ends of the primary coil 10. When the total number of turns of the loop-shaped coil conductor is increased, three or more layers of coil conductors may be connected in series by using the printed board 11 as a multilayer board.

  As shown in FIGS. 5 and 6, the secondary coil 20 is divided into two parts, and includes a secondary coil conductor portion 21 having a low height and a secondary coil conductor portion 22 having a high height. The secondary coil conductor portions 21 and 22 are both bus bars formed with flat plate-like portions 21e and 22e facing each other with the primary coil 10 interposed therebetween, and both are fixed to the conductor pattern on the metal substrate 40 by soldering. 4 legs 21a to 21d and 22a to 22d are integrally provided. The lower ends of the legs 21a to 21d and 22a to 22d are bent in an L shape. In the case shown in the drawing, the two secondary coil conductor portions 21 and 22 both constitute a 3/4 turn winding.

  The metal substrate 40 is an aluminum substrate, for example, on which a copper conductor pattern is formed, and a thin insulating layer exists between the aluminum substrate and the conductor pattern. Then, conductor patterns 41a to 41d insulated from the metal substrate 40 through an insulating layer are formed on the metal substrate 40 corresponding to the four legs 21a to 21d of the secondary coil conductor portion 21, Corresponding to the three legs 22a to 22c of the secondary side coil conductor portion 22, conductor patterns 42a to 42c insulated from the metal substrate 40 through insulating layers are formed on the metal substrate 40. The conductor pattern 41d also corresponds to the remaining leg 22d of the secondary coil conductor portion 22, and is a terminal fitting serving as a midpoint tap in which one ends of both the secondary coil conductor portions 21 and 22 are connected. 45 is connected and fixed by soldering.

  Conductive pattern 43 is insulated on metal substrate 40 to solder rectifying element 30 to conductive pattern 41c, and conductive pattern 44 is similarly insulated to solder rectifying element 30 to conductive pattern 42c. It is formed insulated from the metal substrate 40 through a layer. The conductor patterns 43 and 44 are connected and fixed by soldering terminal fittings 46 and 47 for taking out the rectified output.

  The assembly of the transformer T1 can be performed by the following procedure.

  First, the four legs 21a to 21d of the low-side secondary coil conductor portion 21 shown in FIGS. 5 and 6 are fixed to the conductor patterns 41a to 41d on the metal substrate 40 by soldering, and the height The four legs 22a to 22d of the secondary coil conductor portion 22 having a high height are fixed to the conductor patterns 42a to 42c and 41d by soldering. Then, the primary coil conductor 10 is inserted between the flat plate portion 21e of the lower secondary coil conductor portion 21 and the flat plate portion 22e of the higher secondary coil conductor portion 22 as shown in FIG. To do.

  Then, the I-type ferrite core 16 shown in FIG. 3 is inserted and arranged below the lower secondary coil conductor portion 21, that is, between the four legs 21a to 21d, and the higher secondary coil conductor is arranged. The E-type ferrite core 15 is inserted from the upper side of the portion 22 so that the central leg portion 15a is disposed inside the primary side coil 10 and the secondary side coil 20 (the outer leg portion is the coil 10 or 20). Abutting the I-type ferrite core 16). At the same time, the E-type ferrite core 15 is pressed from above with the core fixing tool 17 whose upper side is curved and has elasticity, and is fixed to the metal substrate 40 with screws 60. The screw 60 may be screwed by forming a female screw in the mounting hole 50 of the metal substrate 40, or the mounting hole 50 is simply penetrated on the assumption that the metal substrate 40 is placed on the heat dissipation base plate 3 of FIG. 1. A structure in which a hole is formed and a female screw hole is provided on the heat radiating base plate 3 side may be used.

  The rectifying unit including the rectifying element 30 connects and fixes the rectifying element 30 between the conductor pattern 41c and the conductor pattern 43 by soldering, and also connects and fixes the rectifying element 30 between the conductor pattern 42c and the conductor pattern 44 by soldering. It is assembled with that. As a result, the end of the secondary coil 20 of the transformer T1 and one end of the rectifying element 30 of the rectifying unit are connected by soldering via the conductor patterns 41c and 42c (the screwing portion can be eliminated). it can). In the rectifying unit, a plurality of rectifying elements 30 may be connected in parallel as shown in FIGS. 1 and 3 in order to satisfy a required current capacity.

  As a result, the assembly of the AC / DC conversion module substrate 1 is completed, but the soldering process can be performed simultaneously with the reloof solder for both the transformer and the rectifying unit.

  The metal substrate 40 of the AC / DC conversion module substrate 1 faces the base plate 3 for heat dissipation, and is fastened and fixed to the base plate 3 with the screws 60 for fixing the transformer and the screws 61 inserted into the mounting holes 51 at the corners of the metal substrate 40 in contact. Is done. In the circuit diagram of FIG. 2, the secondary output terminal (terminal fitting) 45 serving as the midpoint tap of the secondary coil 20 of the transformer T1 is connected to the choke coil 6 via the connection bus bar 70 as shown in FIG. Connected to. Further, terminal fittings 46 and 47 for taking out the rectified output obtained by rectifying the induced voltage of the secondary side coil 20 with the rectifying element 30 (in this case, ground terminals) 46 and 47 It is directly fixed with a screw 62 using a screw hole (as shown in the circuit diagram of FIG. 2, it is electrically connected to the ground). A switching circuit board 5 mounted with a switching circuit 4 for switching the DC voltage of the high-voltage side DC power supply 80 in the circuit diagram of FIG. 2 is connected to the primary side coil 10 of the transformer T1, and the AC output of the switching circuit 4 is supplied. The

  According to the first embodiment, the following effects can be obtained.

(1) Although the secondary coil 20 of the transformer T1 generates a large amount of heat due to a large current, the secondary coil 20 is a series connection of two coil conductor parts 21 and 22 (configured by bus bars), and each coil conductor part The four legs 21a to 21d and 22a to 22d which are the end portions of 21 and 22 are respectively soldered to a conductor pattern formed on the metal substrate 40 via an insulating layer, and the coil conductor portions 21 and 22 are connected to each other. The bus bar to be configured can be fixed to the metal substrate 40 with a small thermal resistance (each leg serves as a heat dissipation path). For this reason, the cooling performance is improved, and the secondary coil 20 can be downsized. In particular, if the metal substrate 40 is directly mounted on the heat radiating base plate 3 of the in-vehicle DC / DC converter 2 as in the overall structure of FIG.

(2) The rectifying element 30 is also fixed by soldering to a conductor pattern formed on the metal substrate 40 via an insulating layer. For this reason, by eliminating the screwing portion of the secondary circuit portion of the transformer T1 on the AC / DC conversion module substrate 1, it is possible to reduce the size, reduce the number of parts, and reduce the number of assembly steps.

(3) The transformer T1 can be pulled out from the secondary coil 20 between the secondary coil 20 by removing the E-type ferrite core 15 by removing the core fixing member 17, and it has good decomposability. It is possible to respond quickly when it is found.

(4) The coil conductor portions 21 and 22 forming the secondary side coil 20 have a sandwich structure in which the primary side coil 10 is sandwiched, and the coil conductor portions 21 and 22 are flat plate portions 21e facing each other across the primary side coil 10. , 22e are formed in the bus bar, the primary coil 10 can be radiated well.

  FIG. 7 shows an AC / DC conversion module substrate according to the second embodiment of the present invention, in which the structure of the magnetic core of the transformer T1 is different. In this case, the magnetic core of the transformer T1 has a combination structure of E-type ferrite cores 18 and 19, and has center legs 18a and 19a disposed inside the primary side coil 10 and the secondary side coil 20, respectively. ing. The E-type ferrite core 18 is assembled from above the secondary coil 20 on the metal substrate 40, and the E-type ferrite core 19 is assembled from below the metal substrate 40 through a hole 48 formed in the metal substrate 40.

  This structure is based on the premise that the lower E-type ferrite core 19 is supported by the base plate when the metal substrate 40 is directly mounted on a heat dissipation base plate (not shown). The upper E-type ferrite core 18 is pressed from above with the core fixing tool 17 whose upper side is curved and elastic, and the fixing tool 17 is passed through the mounting hole 50 of the metal substrate 40 and is fixed to the female of the base plate. Secure to the screw.

  Except for the magnetic core structure, the configuration is the same as that of the first embodiment described above, and the same or corresponding parts are denoted by the same reference numerals and description thereof is omitted.

  In the AC / DC conversion module substrate according to the second embodiment, the lower portion of the lower E-type ferrite core 19 is also located inside the punched hole 48 formed in the metal substrate 40. In comparison, the core volume can be increased by the thickness of the metal substrate 40. Other functions and effects are substantially the same as those of the first embodiment.

  Although the embodiments of the present invention have been described above, it will be obvious to those skilled in the art that the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the claims.

BRIEF DESCRIPTION OF THE DRAWINGS It is a perspective view which shows Embodiment 1 of the AC / DC conversion module board | substrate and vehicle-mounted DC / DC converter which concern on this invention. It is the same circuit diagram. It is an exploded perspective view of an AC / DC conversion module substrate. It is the same perspective view. It is a disassembled perspective view of the secondary side coil part of a transformer. It is the exploded perspective view which changed the projection direction similarly. It is a disassembled perspective view which shows Embodiment 2 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 AC / DC conversion module board | substrate 2 DC / DC converter for vehicles 3 Base plate for heat dissipation 4 Switching circuit 5 Switching circuit board 6 Choke coil 10 Primary side coil 11 Printed circuit board 12 Core insertion hole 15, 18, 19 E type ferrite core 16 I-type ferrite core 17 Fixing tool 20 Secondary coil 21, 22 Secondary coil conductor 30 Rectifier 40 Metal substrate T1 Transformer

Claims (4)

An AC / DC conversion module board comprising: a transformer having a primary side coil and a secondary side coil; a rectifying element that rectifies an induced voltage of the secondary side coil; and a metal board .
The magnetic core of the transformer is mounted on the metal substrate with a fixture,
Having said secondary coil plurality of coil conductor portions is soldered to the conductor pattern end of each coil conductor portion is formed via an insulating layer on the metal substrate, wherein the primary coil Is inserted between the plurality of coil conductor portions ,
The plurality of coil conductor portions have a bus bar structure in which flat plate-like portions opposed to each other with the primary side coil interposed therebetween are formed, and the coil conductor portions are rectified into one of the conductor patterns soldered to the end portions of the coil conductor portions. The elements are connected by soldering,
An in-vehicle DC / DC converter in which the metal substrate of the AC / DC conversion module substrate is fixed to the heat radiating base plate in a face-to-face contact state. The magnetic core of the transformer includes a first core having a central leg disposed inside the primary side coil and the secondary side coil, an outer leg disposed outside the coil, and a flat plate shape. second core consisting of the claims 1 Symbol mounting automotive DC / DC converter of. The magnetic core of the transformer has first and second cores each having a central leg portion disposed inside the primary side coil and the secondary side coil, and an outer leg portion disposed outside the coil. The first core is assembled from above the metal substrate, and the second core is assembled from below the metal substrate through a hole formed in the metal substrate, and the lower surface of the second core. There claim 1 Symbol mounting automotive DC / DC converter is supported by the heat radiating base plate. The switching circuits connected before Symbol primary coil, the AC / DC conversion module substrate Separately the according to claims 1 to obtain Bei on radiating base plate in any one of the three vehicle DC / DC converter.

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