JP2009296017A - Inductance parts, power supply transformer, and switching power supply - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inductance parts, a power supply transformer, and a switching power supply with excellent heat dissipation property, which effectively dissipate heat generated therefrom. <P>SOLUTION: The power supply transformer 1 includes a core parts 2, 3 having primary coils 4, 5, secondary coils 10, 30, and axial cores 2c, 3c each wound with the primary coils and the secondary coils respectively. The secondary coils 10, 30 include flat coils 8, 9, 28, 29 provided with openings 13 at the inside of the ring portion 11. Flat coils 8, 9, 28, 29 include terminals 15, 35 and heat dissipation legs 17, 37 each connected ring portions 11, 31 respectively. The heat dissipation legs 17, 37 sandwich openings 13, 33 respectively and project from each portions facing the terminals 15, 35. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an inductance component, a power supply transformer, and a switching power supply having a heat dissipation structure for releasing generated heat.

  Conventionally, an inductance component such as a choke coil and a power transformer are incorporated in a switching power supply. Among them, the switching power supply mounted on the automobile has a large capacity because a large current flows, and the built-in power transformer has a large capacity. In particular, in such a switching power supply, a large amount of heat is generated from the power transformer, and thus a heat dissipation structure for releasing the heat is provided. Conventionally, with regard to this type of transformer having a heat dissipation structure, the secondary coil is formed from a thin annular metal plate, and the heat connected to the heat dissipation body is branched from the conductive path of the secondary coil. There has been a technique of radiating heat by providing a transmission member (see, for example, Patent Document 1).

  Here, FIG. 12 is an exploded perspective view showing a power transformer 200 having a conventional heat dissipation structure. In this power transformer 200, primary coils 206 and 207 of windings and secondary coils 212 and 213 formed in a flat plate shape are insulated between core components 201 and 202 by insulating members 209, 210, and 211. It is arranged. In the secondary coils 212 and 213, the heat radiation members 215 and 216 are integrally connected to the annular portion so as to branch from the conductive path. The heat radiating members 115 and 116 are connected to a base plate (not shown), and heat is released from the heat radiating members 215 and 216 to the base plate.

Japanese Patent Laid-Open No. 5-16646 (first page)

  When the power transformer 200 is incorporated in a switching power supply, the terminal portions 212a and 213a must be connected to another electric circuit. For example, when rectifying an alternating current that has been stepped down by the power transformer 200, the terminal portions 212a and 213a must be connected to terminals of a circuit (rectifier circuit portion) that performs the rectification. However, in the power transformer 200, the heat dissipating members 215 and 216 and the terminal portions 212a and 213a protrude from the same side of the cores 201 and 202 and are arranged side by side. It had to be connected to the terminal of the rectifier circuit part via the bus bar).

  Therefore, in this case, when a large current flows through the power supply as in an in-vehicle switching power supply, relatively large heat is also generated from the current flowing through the circuit components (bus bars) from the terminal portions 212a and 213a. The loss due to the change of current to heat was large. Further, since the secondary coils 212 and 213 generate a larger amount of heat due to the current flowing through the annular portion, the generated heat is sufficiently released even if the heat dissipating members 215 and 216 are provided at the peripheral end portions of the annular portion. It could not be said that it was done. For this reason, in the conventional power transformer 200, heat concentrates on a specific location of the secondary coils 212 and 213, the characteristics deteriorate (and the characteristics become unstable), and the heat stays inside. Therefore, there is a problem that the heat dissipation efficiency of the switching power supply is remarkably lowered.

  Such a problem related to a decrease in heat dissipation efficiency is a problem that can occur not only in the secondary coil but also in the primary coil as the current increases. In addition to the power transformer, a flat coil corresponding to a large current is provided. This is also a problem that may occur in an inductance component such as a choke coil.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-described problems and to provide an inductance component, a power transformer, and a switching power supply having a heat dissipation structure in which generated heat is efficiently released and heat dissipation characteristics are good.

  In order to solve the above problems, the present invention provides a coil comprising a flat plate member having an annular portion, a terminal portion connected to the annular portion, connected to another member, and a heat radiation foot portion for releasing heat to the outside. And a core having an axial core portion disposed inside the annular portion, and characterized in that the heat radiation foot protrudes from the side facing the terminal portion across the hole portion inside the annular portion. To do.

  In this inductance component, the heat dissipating foot and the terminal portion are arranged on opposite sides of the core, so the length of the terminal portion increases corresponding to the protrusion of the heat dissipating foot portion. And generation of heat can be suppressed. In addition, since the heat dissipation foot is connected to the middle of the annular portion, heat dissipation is performed efficiently.

  The inductance component may be further provided with a base plate for fixing the inductance component, and a heat radiation foot may be connected to the base plate so that heat can be radiated while maintaining insulation. In this way, heat can be reliably released from the heat dissipation foot, and no current flows from the heat dissipation foot to the base plate.

  In this inductance component, the two coils can be provided, and the heat radiation feet of the coils can be arranged side by side and connected to the base plate via a common insulating sheet. In this way, since the insulating sheet becomes common, the connection work is simplified and the insulating sheet is not wasted.

  The present invention also includes a primary coil and a secondary coil arranged so as to be insulated from each other, and a core having an axial core portion around which the primary coil and the secondary coil are wound. Alternatively, at least one of the secondary coils is composed of an annular part, a flat plate member having a terminal part connected to the annular part, connected to another member, and a heat radiation foot part for releasing heat to the outside. Provided is a power transformer in which a foot portion protrudes from a side facing a terminal portion with a hole inside an annular portion interposed therebetween.

  In this power transformer, since the heat dissipation foot and the terminal portion are arranged on opposite sides of the core, the length of the terminal portion becomes longer corresponding to the protrusion of the heat dissipation foot. And generation of heat can be suppressed. Moreover, since the heat radiating foot is connected to the middle of the annular portion, the heat is radiated efficiently.

  The present invention further includes a primary coil and a secondary coil arranged so as to be insulated from each other, and a core having an axial core portion around which the primary coil and the secondary coil are wound. Alternatively, at least one of the secondary coils is formed of a flat plate member having an annular part, a terminal part connected to the annular part, connected to another member, and a heat radiation foot part for releasing heat to the outside. Provided is a power transformer having two opposed openings for deriving a terminal portion and a heat radiation foot, the terminal portion protruding from one of the openings, and the heat radiation foot protruding from the other of the openings .

  In this power transformer, the heat radiation foot and the terminal portion are arranged on opposite sides of the core, so the length of the terminal portion becomes longer corresponding to the protrusion of the heat radiation foot. And generation of heat can be suppressed. In addition, since the heat dissipation foot is connected to the middle of the annular portion, heat dissipation is performed efficiently.

  Further, in these power transformers, a base plate for fixing the power transformer may be further provided, and heat radiation feet may be connected to the base plate so that heat can be radiated while maintaining insulation.

  Furthermore, it is good to have two primary coils or secondary coils which consist of a flat member, and each heat radiation foot of each coil is arranged side by side, and is connected to the base plate through a common insulating sheet. .

  The present invention provides a power transformer including a primary coil and a secondary coil arranged so as to be insulated from each other, and a core having an axial core portion around which the primary coil and the secondary coil are wound, A switching power supply having a switching means for converting a direct current input into an alternating current, wherein at least one of the primary coil or the secondary coil is connected to the annular portion, the annular portion, and a terminal portion connected to another member and the outside Provided is a switching power supply comprising a flat plate-like member provided with a heat radiating foot for releasing heat, wherein the heat radiating foot protrudes from the side facing the terminal portion across the hole inside the annular portion.

  The present invention also provides a power transformer including a primary coil and a secondary coil arranged so as to be insulated from each other, and a core having an axial core portion around which the primary coil and the secondary coil are wound. A switching power supply having a rectifier circuit unit that rectifies the current stepped down by the power transformer, wherein at least one of the primary coil or the secondary coil is connected to the annular part, the annular part, and connected to another member Switching power supply comprising a flat plate-like member having a terminal portion to be radiated and a heat radiation foot portion for releasing heat to the outside, and the heat radiation foot portion is disposed on the side facing the rectifier circuit portion across the core I will provide a.

  These switching power supplies may be further provided with a base plate for fixing the power transformer, and a heat radiation foot may be connected to the base plate so that heat can be radiated while maintaining insulation.

  According to the present invention, in the inductance component, the power transformer, and the switching power supply, the generated heat is efficiently released, and the heat dissipation characteristics can be improved.

1 is an exploded perspective view of a power transformer according to an embodiment of the present invention. It is a perspective view which expands and shows the secondary coil 10 of the power transformer shown in FIG. Similarly, it is a perspective view showing a secondary coil 30 in an enlarged manner. It is a perspective view which shows the power transformer and rectifier element part in the switching power supply in which the power transformer shown in FIG. 1 and a rectifier element part are incorporated. 1 is a circuit diagram of a switching power supply according to an embodiment of the present invention. Similarly, it is a perspective view of a switching power supply. 2 is an exploded perspective view of a power transformer 100. FIG. It is a perspective view which shows the power transformer and the rectifier element part in the switching power supply in which the power transformer 100 and the rectifier element part are incorporated. It is a side view which shows the state which accumulated the coil components 2 and 3. FIG. FIG. 10 is a plan view of a state where the coil components 2 and 3 shown in FIG. 9 are stacked. It is sectional drawing which shows the structure of another foot part for thermal radiation. It is a disassembled perspective view of the conventional power transformer.

  Embodiments of the present invention will be described below. In addition, the same code | symbol is used for the same element and the overlapping description is abbreviate | omitted.

  FIG. 1 is an exploded perspective view of a power transformer 1 according to an embodiment of the present invention. This power transformer 1 is configured by disposing primary coils 4 and 5 and secondary coils 10 and 30 between core parts 2 and 3 so as to be insulated from each other by insulating members 21, 22 and 23. ing.

  As shown in FIGS. 9 and 10, the core parts 2 and 3 have outer leg portions 2b and 3b that protrude from both sides of the base portions 2a and 3a in the width direction, respectively. It has parts 2c and 3c. The core parts 2 and 3 are provided with primary coils 4 and 5 and secondary coils 10 and 30 so that the outer legs 2b and 3b are in contact with each other so that the shaft cores 2c and 3c are wound. When it is made to overlap (overlapping), the axial core parts 2c and 3c face each other and the gap 6 is formed. The base portions 2a and 3a and the outer leg portions 2b and 3b form two opposed openings 12 and 14 with the shaft core portions 2c and 3c interposed therebetween. In the drawing, the gap 6 is formed between the shaft core portions 2c and 3c. However, in the present invention, the gap 6 may not be formed by the core components 2 and 3.

  The primary coils 4 and 5 are made of an electric wire made of copper or other material having excellent conductivity and heat conductivity, and the electric wire is wound so as to have a hole 4a or 5a at the center and formed into a flat plate shape. Is. Further, the primary coils 4 and 5 have terminal portions 4b and 5b connected to different members at the tip end portions of the electric wires, and the terminal portions 4b and 5b are connected to the outside of the core parts 2 and 3 from one opening portion 14. To be derived.

  As shown in FIG. 2, the secondary coil 10 includes two flat coils 8 and 9 having the same shape. Each of the flat coils 8 and 9 includes an annular portion 11 in which a flat plate member made of copper or other material having excellent conductivity and heat conductivity is formed in an annular shape, a terminal portion 15 connected to another member, and the outside. It has a heat dissipation foot 17 for releasing heat.

  The annular portion 11 has a gap 11 a formed between two peripheral end portions, has a predetermined line width, and has an inner hole 13. Further, the terminal portion 15 and the heat radiation foot portion 17 are connected to each other, and both of them protrude from the sides facing each other with the hole portion 13 interposed therebetween.

  The terminal portion 15 includes two terminal portions 15 a and 15 b, which protrude from the peripheral end portion forming the gap 11 a in the annular portion 11 and are led out of the core components 2 and 3 from one opening portion 12. ing. The terminal portions 15a and 15b are formed so as to be connectable to different members by screwing, welding, or the like. In this embodiment, the screw holes are connected to the rectifier circuit 75 of the switching power supply 70 described later by screwing. Is formed.

  The heat dissipating foot 17 includes a projecting portion 17a connected to the middle (intermediate portion) of the annular portion 11, and a base portion 17b formed in an L shape from the projecting portion 17a. The heat dissipating foot 17 is formed so as to branch from the conductive path of the respective flat coils 8 and 9, and is led out of the core parts 2 and 3 from the other opening 14. The distal end side of the base portion 17b is a receiving portion 17c with a screw hole.

  As shown in FIG. 3, the secondary coil 30 includes two flat coils 28 and 29 having the same shape. Each of the flat coils 28 and 29 includes, as in the flat coils 8 and 9, an annular portion 31 in which a flat plate member made of a material having excellent conductivity and thermal conductivity such as copper is formed in an annular shape, and a terminal portion. 35 and a heat radiation foot 37.

  The annular portion 31 has a gap 31 a formed between two peripheral end portions, has a predetermined line width, and has a hole 33 inside thereof. Moreover, the terminal part 35 and the radiation | emission leg | foot part 37 are connected, and both protrude from the side which mutually opposes on both sides of the hole 33 similarly to each flat coil 8 and 9. FIG.

  The terminal portion 35 includes two terminal portions 35a and 35b having shapes different from those of the terminal portions 15a and 15b. The terminal portion 35 protrudes from the peripheral end portion forming the gap 31a in the annular portion 31 and is external to the core parts 2 and 3 from the opening portion 12. To be derived. Similarly to the terminal portions 15a and 15b, the terminal portions 35a and 35b are formed so as to be connectable to different members, and are formed with screw holes.

  The heat radiating foot 37 includes a projecting portion 37a connected to the middle (intermediate portion) of the annular portion 31 and a base portion 37b formed in an L shape from the projecting portion 37a. The heat radiating foot 37 is formed so as to branch from the conductive path of each flat coil 28, 29, and is led out of the core parts 2, 3 from the opening 14. The distal end side of the base portion 37b is a receiving portion 37c with a screw hole.

  As shown in FIG. 1, the insulating members 21, 22, and 23 are members formed in an annular shape having holes 21 a, 22 a, and 23 a at the center, and are respectively a core component 2, a secondary coil 10, and a secondary It arrange | positions so that the coil 30 and the core component 3 can be insulated.

  The power transformer 1 is constructed by assembling each component having the above configuration while maintaining the positional relationship shown in FIG.

  That is, since the primary coils 4, 5, the secondary coils 10, 30, and the insulating members 21, 22, 23 each have a hole in the center, the cores of the core components 2, 3 are provided inside the holes. The parts 2c and 3c are fitted and assembled as follows.

  First, in the secondary coil 10, the flat coils 8 and 9 are overlapped with the primary coil 4 interposed therebetween, while in the secondary coil 30, the flat coils 28 and 29 are interposed with the primary coil 5 interposed therebetween. Overlapping. Then, while interposing the insulating members 21, 22, and 23, the core component 2 (the shaft core portion 2c) is inserted from above into the hole of each component, while the core component 3 (the shaft core portion 3c). ) Is inserted from the lower side so that the shaft core portions 2c and 3c face each other (or contact surfaces). At the same time, the outer legs 2b and 3b are brought into contact with each other.

  At this time, since the terminal portions 15 and 35 and the heat radiation feet 17 and 37 protrude from the opposite sides across the holes 13 and 33, as shown in FIG. The latter can be derived from the opening 12 and the latter can be derived from the opening 14 on the opposite side. As a result, a structure in which the terminal portions 15 and 35 and the heat radiation feet 17 and 37 protrude to the opposite sides with the core components 2 and 3 interposed therebetween is obtained (hereinafter, this structure is referred to as “opposite protruding structure”). Further, when the terminal portions 15b and 15b and the terminal portions 35b and 35b are connected to each other by inserting screws through the secondary coils 10 and 30, the heat radiation feet 17 and 37 are arranged side by side, and the above-described power transformer 1 can get.

  Further, the power transformer 1 connects the heat dissipating feet 17 and 37 to the fixing member with a structure capable of radiating heat while maintaining insulation (hereinafter, this structure is referred to as “insulation holding structure”). In the present embodiment, the insulation holding structure is configured as follows. First, as shown in FIG. 2, it has a screw hole and is larger in size than the receiving portions 17c and 37c of the heat dissipating feet 17 and 37, and is common to the heat dissipating feet 17 and 37 (heat dissipating feet). An insulating sheet 38 (which can mount both the parts 17 and 37) is placed on the fixing member. Next, the receiving portions 17 c and 37 c are placed on the insulating sheet 38. In addition, an annular resin pad 39 having a screw hole of a size corresponding to the screw hole of the receiving portions 17c and 37c is attached to the screw 40, and then the screw 40 with the resin pad is attached to the screw of the receiving portions 17c and 37c. It is inserted into the hole, and further inserted into the screw hole of the insulating sheet 38 and screwed into the fixing member.

  Then, since the screw 40 is screwed through the insulating sheet 38 and the resin pad 39, the screw 40 is not in direct contact with the heat dissipating feet 17, 37, and the heat dissipating feet 17, 37 are on the surface of the fixing member. It is fixed to the fixing member in a state where it is not in direct contact (with the insulating sheet 38 interposed). Thus, the heat radiation feet 17 and 37 to the fixing member are integrated while maintaining insulation. In this case, since the common insulating sheet 38 is used for the heat radiation feet 17 and 37, the connection work is simplified and the waste of the insulation sheet can be eliminated. Each may be provided separately.

  Since these heat radiation feet 17 and 37 are integrated with the secondary coils 10 and 30, the current flowing through the secondary coils 10 and 30 also flows through the heat radiation feet 17 and 37. Since 17 and 37 are connected to the fixing member by the above-described insulating holding structure, the current does not flow from the heat radiation feet 17 and 37 to the fixing member, and the insulating state is maintained. Further, since the heat radiation feet 17 and 37 to the fixing member are integrated, the heat generated from the secondary coils 10 and 30 passes from the heat radiation feet 17 and 37 through the resin pad 39 and the insulating sheet 38. Is transmitted to the fixing member. In this way, the heat radiation feet 17 and 37 are connected in a structure capable of heat radiation while maintaining insulation. In the power transformer 1, heat is generated not only from the secondary coils 10 and 30, but also from the primary coils 4 and 5. The heat is transmitted to the secondary coils 10 and 30, and the heat radiation feet 17 and 37 are transmitted. Is released through.

  Here, as shown in FIG. 11, the above-described heat radiation feet 17, 37 are connected to the protrusions 17a, 37a to form flat bases 17d, 37d along the protrusions 17a, 37a. , 37d may be formed with screw holes formed at the tips thereof. When the heat radiation feet 17 and 37 are connected to the fixing member by the insulating holding structure, the fixing member (assuming a base plate 71 described later in FIG. 11) is provided with a columnar protrusion 71a, and the columnar protrusion 71a is insulated. What is necessary is just to fix via the sheet | seat 38. FIG.

  By the way, when the heat radiation members 215 and 216 protrude from the same side of the terminal portions 212a and 213a and the cores 201 and 202 as in the conventional power transformer 200 described above, the terminal portions 212a and 213a are connected via the bus bars. It had to be connected to another member such as a terminal of the rectifier circuit section. Further, since the heat dissipating members 215 and 216 are connected to the peripheral end portion away from the annular portion that generates more heat, heat is not sufficiently released.

  On the other hand, since the power transformer 1 according to the present embodiment has the opposite projecting structure with the terminal portions 15 and 35 and the heat dissipation feet 17 and 37 as described above, the heat dissipation feet 17 and 37 are It is arranged on the opposite side to the other member with the core parts 2 and 3 in between. Therefore, the terminal parts 15 and 35 do not need to bother through a bus bar, and can be directly connected to another member. Therefore, heat is not generated by the current flowing through the bus bar from the terminal portions 15 and 37, and loss due to the change of the current to heat is not generated.

  The secondary coils 10 and 30 generate a larger amount of heat due to the current flowing through the annular portions 11 and 31, but the heat radiation feet 17 and 37 for releasing the heat are intermediate between the annular portions 11 and 31, respectively. Connected to the part. Therefore, the heat generated from the annular portions 11 and 31 is efficiently released from the heat radiation feet 17 and 37 and does not stay. Therefore, heat is sufficiently released by the heat dissipating feet 17 and 37, and the heat dissipation efficiency of the power transformer 1 is improved.

  Next, the switching power supply 70 having the above-described power transformer 1 and rectifier circuit 75 will be described. This switching power supply 70 is mounted on an automobile (in particular, an automobile that requires a relatively large current, such as a hybrid vehicle or a fuel cell vehicle that uses a gasoline engine and an electric motor as a power source) and is input from a battery. An electric circuit for stepping down and outputting the DC voltage to be output.

  5 and 6, the switching power supply 70 has a base plate 71. On the base plate, an input filter 72, a switching circuit 73, a main transformer 74, a rectifier circuit 75, and a smoothing circuit are provided. 76 and the output filter 77 are fixed (for convenience of illustration, the output filter 77 is not shown in FIG. 5).

  The input filter 72 is composed of circuit elements for removing noise from the current input from the vehicle battery and preventing malfunction of a control circuit (not shown) of the switching power supply 70. The switching circuit 73 is a switching means having a plurality of switching elements such as FETs, and is composed of circuit elements that convert the DC input output from the input filter 72 into AC. The main transformer 74 receives the alternating current output from the switching circuit 73 and converts the voltage into a predetermined value (step-down conversion). The main transformer 74 has the same configuration as the power transformer 1 described above.

  In the main transformer 74, the (primary side) terminal portions 4b and 5b of the primary coils 4 and 5 are connected to the switching circuit 73, while the (secondary side) terminal portions 15a and 35a of the secondary coils 10 and 30 are rectified. Connected to the circuit 75, the terminal portions 15b and 35b are grounded (fixed to the base plate 71). Further, the heat radiation feet 17 and 37 form the above-described opposite projecting structure together with the terminal portions 15 and 35, and are fixed to the base plate 71 by the above-described insulating holding structure.

  The rectifier circuit 75 has a plurality of rectifier elements that rectify and output the alternating current output from the main transformer 74, and is arranged in parallel with the main transformer 74 as shown in FIG. The smoothing circuit 76 includes a choke coil 78 and a capacitor 79. The smoothing circuit 76 receives a rectified current, removes an AC component, and smoothes the current.

  As shown in FIG. 4, the main transformer 74 holds the core parts 2 and 3 by a leaf spring 81 and is fixed to the base plate 71. Since the main transformer 74 has the above-described opposite projecting structure, the heat radiation feet 17 and 37 are disposed on the side facing the rectifier circuit 75 with the core parts 2 and 3 interposed therebetween. Therefore, since the main transformer 74 can directly connect the terminal portions 15a and 35a to the rectifier circuit 75, heat is not generated from the bus bar, and the heat radiation by the heat radiation feet 17 and 37 is sufficiently performed.

  Further, the heat radiation feet 17 and 37 are fixed to the base plate 71 by the above-described insulating holding structure, and the base plate 71 is equipped with a radiator such as a water jacket (not shown). Therefore, the heat transmitted from the heat radiation feet 17 and 37 to the base plate 71 can be released very efficiently.

  Here, for comparison with the power supply transformer 1 described above, a case where the main transformer 74 is configured by the power supply transformer 100 shown in FIGS. In this power transformer 100, flat secondary coils 103 and 104 having an annular portion and a primary coil 105 of a winding are provided between core components 101 and 102. The secondary coils 103 and 104 have heat radiation legs 106 and 107 branched from the conductive paths, and terminal parts 103a and 104a.

  Then, the main transformer 74 composed of the power transformer 100 is fixed to the base plate 71. As shown in FIG. 8, the heat radiation feet 106 and 107 are on the same side of the core parts 101 and 102 as the terminal portions 103a and 104a. Therefore, a space having a width W1 shown in FIG. 8 must be secured between the radiating circuit 75 and the rectifying circuit 75 in correspondence with the protrusion of the heat radiation feet 106 and 107. Therefore, if the terminal portions 103a and 104a are directly connected to the heat radiation feet 106 and 107, the length of the terminal portions 103a and 104a has to be increased, and the heat generation is increased accordingly. Further, since the heat radiating feet 106 and 107 were formed at the peripheral end of the annular portion, the generated heat was not sufficiently released. Therefore, the temperature distribution of the secondary coils 103 and 104 is not uniform.

  On the other hand, when the main transformer 74 is constituted by the above-described power transformer 1, the protrusion of the heat radiation foot between the core parts 2 and 3 and the rectifier circuit 75 is eliminated due to the above-described opposite protruding structure. Therefore, as shown in FIG. 4, a space of W2 (W1> W2) in which the distance between the core components 2 and 3 and the rectifier circuit 75 is significantly smaller than the width W1 is sufficient. Further, since the heat dissipating feet 17 and 37 are connected to the intermediate portions of the annular portions 11 and 31, respectively, the heat generated from the annular portions 11 and 31 is efficiently released from the heat dissipating feet 17 and 37 and stays there. There is nothing to do. Therefore, by configuring the main transformer 74 with the above-described power transformer 1, heat generation can be suppressed, and heat radiation by the heat radiation feet 15 and 37 can be sufficiently performed, so that heat radiation characteristics can be improved. .

  In particular, the main transformer 74 is constituted by the power transformer 1, and the heat radiation feet 17 and 37 are fixed to the base plate 71 as described above, and the terminal portions 15b and 35b are also fixed to the base plate 71 (grounded). In other words, heat can be radiated from the terminal portions 15b and 35b, so that two heat radiation routes are formed on both sides of the secondary coils 10 and 30 (annular portions 11 and 31). Therefore, since the main transformer 74 (and the secondary coils 10 and 30) can perform heat dissipation in a distributed manner, the heat distribution is uniform and uniform, and the heat dissipation efficiency is further improved.

  In the above description, the case where the heat radiation foot is provided in the secondary coil of the power transformer is described as an example. However, since heat is also generated in the primary coil, in order to efficiently release the heat. The primary coil may be provided with a heat radiation foot so as to have the above-described opposite projecting structure. Further, the present invention can be applied not only to a power transformer but also to an inductance component such as a choke coil having a plate-like coil made of an annular bus bar made of a flat plate member and a core.

DESCRIPTION OF SYMBOLS 1 ... Power supply transformer, 2, 3 ... Core components, 4, 5 ... Primary coil, 2c, 3c ... Shaft core part, 8, 9, 28, 29 ... Flat coil, 10, 30 ... Secondary coil, 12, DESCRIPTION OF SYMBOLS 14 ... Opening part, 11, 31 ... Annular part, 13, 33 ... Hole part, 15, 15a, 15b ... Terminal part, 35, 35a, 35b ... Terminal part, 17, 37 ... Radiation foot part, 70 ... Switching power supply 71 ... Base plate.

Claims (5)

A coil in which an intermediate portion of the flat plate member is formed in an annular shape to provide an annular portion;
A core having an axial core portion disposed inside the annular portion,
The coil is
A terminal part projecting outward from the annular part from each of two peripheral end parts forming a gap between each other, the terminal part formed at both ends of the flat plate member;
A heat radiation foot projecting outward from the annular part from the middle of the annular part on the side facing the terminal part across the hole part inside the annular part,
An inductance component comprising: A primary coil and a secondary coil which are arranged so as to be insulated from each other, and in which an intermediate portion of the flat plate member is formed in an annular shape to provide an annular portion;
A core having an axial core portion around which the primary coil and the secondary coil are wound,
At least one of the primary coil and the secondary coil is
A terminal part projecting outward from the annular part from each of two peripheral end parts forming a gap between each other, the terminal part formed at both ends of the flat plate member;
A heat radiation foot projecting outward from the annular part from the middle of the annular part on the side facing the terminal part across the hole part inside the annular part,
The core has an opening that opposes the terminal portion and the heat radiation foot,
The power transformer, wherein the terminal portion protrudes from one of the openings, and the heat radiation foot protrudes from the other of the openings. It has a base plate with columnar protrusions,
3. The power source according to claim 2, wherein the heat dissipating foot protrudes flatly from the annular portion, and a tip of the heat dissipating foot extending flat is fixed to the columnar protrusion via an insulating sheet. Trance. A primary coil and a secondary coil, which are arranged so as to be insulated from each other and in which an intermediate portion of the flat plate member is formed in an annular shape and provided with an annular portion, and a shaft around which the primary coil and the secondary coil are wound A power transformer having a core including a core part;
Switching means for converting DC input to AC;
A rectifier circuit unit that rectifies the current stepped down by the power transformer, and a switching power source comprising:
At least one of the primary coil and the secondary coil is
A terminal part projecting outward from the annular part from each of two peripheral end parts forming a gap between each other, the terminal part formed at both ends of the flat plate member;
A heat radiation foot projecting outward from the annular part from the middle of the annular part on the side facing the terminal part across the hole part inside the annular part,
The switching power supply, wherein the heat dissipating foot is disposed on a side facing the rectifier circuit with the core interposed therebetween. The secondary coil of the power transformer has the terminal portion and the heat radiation foot, and the power transformer and the rectifier circuit are arranged in parallel.
The switching power supply according to claim 4, wherein the terminal portion of the secondary coil is directly connected to the rectifier circuit.

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