JP4349526B2 - Transformer and transformer manufacturing method - Google Patents

Description

  The present invention relates to a transformer used in a power supply circuit for electronic equipment such as a backlight power supply circuit for a liquid crystal screen, and a method for manufacturing the transformer.

  In a general transformer, a bobbin around which a primary winding and a secondary winding are wound is sandwiched between a pair of vertically opposed cores. Therefore, when heat is generated in the winding portion, the heat is trapped in the core portion, and not only the performance as designed cannot be exhibited, but in the worst case, there is a problem that the failure of the device is caused.

  2. Description of the Related Art Conventionally, various techniques for processing heat generated from a winding portion have been developed in transformers used in power supply circuits for electronic devices.

  For example, a thermal conductive layer made of a silicon resin layer or the like is formed between the primary winding and the secondary winding to improve the thermal conductivity between the primary winding and the secondary winding. A transformer is disclosed in which heat generated in the primary winding is conducted to the secondary winding, and heat is dissipated inside the transformer by cooling fins of a diode module directly connected to the secondary winding. (For example, refer to Patent Document 1).

JP 2002-237416 A

  However, in the conventional transformer described in Patent Document 1, a heat conduction layer made of a silicon resin layer or the like must be interposed between the primary winding and the secondary winding, which increases the number of parts. As a result, the manufacturing process becomes complicated and the manufacturing cost increases.

  The present invention has been proposed in view of the above-described circumstances, and can reliably exhibit the performance as designed by efficiently dissipating the heat generated inside the transformer to the outside without increasing the number of parts. An object of the present invention is to provide a transformer that can be manufactured and that has excellent durability and can reduce the manufacturing cost, and a method for manufacturing such a transformer.

  The transformer and the method of manufacturing the transformer of the present invention have the following features in order to achieve the above-described object.

That is, the transformer of the present invention includes a core portion that houses a primary winding and a secondary winding to form a closed magnetic circuit, and performs electromagnetic induction between the primary winding and the secondary winding. In transformer
The core portion includes a first core having a pair of side legs erected from a base portion and at least one central leg disposed within a distance between the pair of side legs, and an upper portion of the first core A second core disposed so as to close the open surface;
A bobbin-shaped winding frame for winding the primary winding and the secondary winding is attached to the outer periphery of the central leg,
The second core has at least 1 at a position facing a gap formed between the outer peripheral surface of the central leg and the inner peripheral surface of the winding frame portion when the winding frame portion is attached to the central leg. One through hole is provided.

  In addition to the above configuration, the transformer of the present invention is formed so that a gap formed between the outer peripheral surface of the central leg and the inner peripheral surface of the winding frame portion is increased in diameter upward. Preferably it is.

  In this case, by making the inner peripheral surface of the winding frame portion a tapered surface whose diameter is increased upward, the gap portion can be increased in diameter upward, and the outer peripheral surface of the central leg is By using a tapered surface whose diameter is reduced upward, the gap portion can be increased in diameter upward.

The transformer manufacturing method of the present invention includes a core portion that houses a primary winding and a secondary winding to form a closed magnetic circuit, and performs electromagnetic induction between the primary winding and the secondary winding. A method of manufacturing a transformer,
The core portion includes a first core having a pair of side legs erected from a base portion and at least one central leg disposed within a distance between the pair of side legs, and an upper portion of the first core Forming a second core disposed so as to close the open surface;
A bobbin-shaped winding frame for winding the primary winding and the secondary winding is attached to the outer periphery of the central leg,
The second core has at least 1 at a position facing a gap formed between the outer peripheral surface of the central leg and the inner peripheral surface of the winding frame portion when the winding frame portion is attached to the central leg. Formed so that two through holes are opened,
Thereafter, by injecting an adhesive into a gap formed between the outer peripheral surface of the central leg and the inner peripheral surface of the winding frame portion from the through hole provided in the second core, the first core, The winding frame portion and the second core are bonded together.

  In the transformer of the present invention, at least one through hole is formed in the second core that closes the upper open surface of the first core. And this through-hole is provided in the position facing the clearance gap produced between the outer peripheral surface of the center leg which attaches a bobbin-shaped winding frame part, and the inner peripheral surface of a winding frame part.

  For this reason, the heat generated in the winding part is released to the outside of the core part from the through hole provided in the second core. Therefore, it is possible to dissipate the heat generated in the core part to the outside of the core part without providing a special member such as a heat conduction layer made of a silicon resin layer, etc., reducing the number of parts and manufacturing costs. And can be manufactured easily. Furthermore, since heat does not accumulate in the core portion, the performance as designed can be surely exhibited, and the durability of the transformer can be improved.

  In addition, the transformer of the present invention has a gap between the inner peripheral surface of the winding frame portion that has a taper surface that is increased in diameter upward, and the outer peripheral surface of the center leg that is reduced in diameter upward. The diameter of the part is increased upward.

  Therefore, even if a minute error occurs in the mounting position of the second core in the manufacturing process, a through hole provided in the second core is generated between the outer peripheral surface of the center leg and the inner peripheral surface of the winding frame portion. It can be made to oppose a gap | interval part, and the heat | fever generate | occur | produced in the core part can be dissipated reliably outside the core part.

Further, according to the transformer manufacturing method of the present invention, a transformer having excellent heat dissipation can be easily and inexpensively manufactured. Further, by injecting an adhesive into a gap formed between the outer peripheral surface of the central leg and the inner peripheral surface of the winding frame portion from the through hole provided in the second core, the first core, the winding frame portion, and Since the second core can be bonded together, the number of steps in the manufacturing process can be reduced, and the manufacturing cost can be reduced.
When injecting the adhesive into the gap from the through hole, the entire gap is not filled with the adhesive, but the adhesive hardly adheres above the gap and in the through hole. By injecting the adhesive in this way, the heat generated in the core part can be reliably dissipated to the outside of the core part through the gap part and the through hole.

  Hereinafter, with reference to the drawings, embodiments of a transformer and a method of manufacturing the transformer of the present invention will be described. In the embodiment described below, a leakage transformer will be described as an example.

  1 to 4 show a leakage transformer according to an embodiment of the present invention. FIG. 1 is an exploded perspective view of the leakage transformer, FIG. 2A is a plan view of the leakage transformer, and FIG. 2A is a cross-sectional view taken along line AA, FIG. 3 is a partial cross-sectional view of the central leg and the winding frame portion of the first core constituting the leakage transformer, and FIG. 4 is a central leg of the first core constituting the leakage transformer. It is a partial cross section figure which shows other embodiment of a winding frame part.

<Leakage transformer>
The leakage transformer according to the present embodiment is formed such that an air gap is provided between the center leg of the first core and the second core, whereby a slight leakage magnetic flux is generated. The leakage transformer according to the present embodiment is used for a lighting circuit for lighting a backlight of a liquid crystal display device, and is generally called a double leakage transformer, and two CCFLs (cold cathode discharge lamps). ) Are used in a DC / AC inverter circuit for simultaneously discharging and lighting.

  As shown in FIGS. 1 to 4, the leakage transformer 10 includes core portions (first core 20 and second core 30) that house the primary winding 70 and the secondary winding 80 and form a closed magnetic circuit. And electromagnetic induction is performed between the primary winding 70 and the secondary winding 80.

<Core part>
The core portion includes a first core 20 and a second core 30 that closes the upper open surface of the first core 20.

  The first core 20 has a pair of side legs 22 erected from the base portion 21 and a pair of central legs 23 disposed within a distance between the pair of side legs 22. Further, the base portion 21 is provided with a pair of support columns 24 for attaching the spacer 50 so as to be positioned between the pair of central legs 23. The first core 20 and the second core 30 are formed using, for example, ferrite.

<Reel part>
A pair of winding frame portions 40 attached to the outer peripheral portion of each central leg 23 has a bobbin shape and is attached on a gantry 41 made of an insulating member. The gantry 41 is provided with terminal portions 42 a, 43 a, 46 a and linking terminals 43 b, 46 b for connecting the ends of the primary winding 70 and the secondary winding 80. The terminal portions 42 a, 43 a, 46 a and the binding terminals 43 b, 46 b are provided on both sides of the gantry 41, and the terminal portion 43 a and the entanglement are lateral to the terminal portion 42 a connecting the primary winding 70. A bent terminal 43b is provided. The terminal portion 43a and the binding terminal 43b communicate with each other inside the gantry 41, one end of the secondary winding 80 is connected to the binding terminal 46b, and the other end is connected to the binding terminal 43b. Connected.

  The outer periphery of the winding frame portion 40 is provided with flange portions 44a to 44c at the lower end portion, the intermediate portion, and the upper end portion. A secondary winding portion for winding 80 is used, and a space between the flange portion 44c at the upper end and the flange portion 44b at the intermediate portion is a primary winding portion for winding the primary winding 70. ing. The primary winding portion and the secondary winding portion may be configured upside down.

  The inner peripheral diameter of the winding frame portion 40 is formed slightly larger than the outer peripheral diameter of the central leg 23 provided on the first core 20, and the outer peripheral surface of the central leg 23 and the inner peripheral surface of the winding frame portion 40 are formed. A gap 90 is formed between them.

  Further, as shown in FIG. 3, the winding frame portion 40 has a tapered surface 45 whose inner peripheral surface is increased in diameter upward, so that the gap portion 90 is expanded in diameter upward. Yes. It should be noted that the position where the diameter of the inner peripheral surface of the winding frame portion 40 is started may be any position as long as it is between the lower end portion and the upper end portion of the winding frame portion 40.

  In addition, as shown in FIG. 4, the gap portion 90 may be increased in diameter upward by using a tapered surface 25 whose outer diameter is reduced upward. Also in this case, the position at which the diameter reduction of the outer peripheral surface of the center leg 23 is started may be any position as long as it is between the lower end portion and the upper end portion of the center leg 23.

<Spacer>
The spacer 50 is a member for defining the interval between the pair of winding frame portions 40 and positioning the second core 30. The spacer 50 is provided on the first core 20, the separation plate 52 provided downward from the lower surface of the substrate 51, positioning protrusions 53 provided on both sides of the upper surface of the substrate 51, and the first core 20. And a pair of insertion holes 54 through which the support columns 24 are inserted.

<Second core>
The second core 30 is provided with an engagement recess 32 that engages with the positioning protrusion 53 of the spacer 50 on the side surface in the longitudinal direction of the plate-shaped main body 31, and the outer peripheral surface of the center leg 23 and the reel portion 40. A through-hole 33 is provided at a position facing the gap 90 that is formed between the inner peripheral surface and the inner peripheral surface. In the embodiment shown in FIGS. 1 and 2, one through hole 33 is provided for each gap 90, but two, three, or four for each gap 90. You may provide above.

<Manufacturing of leakage transformer>
Next, a method for manufacturing the leakage transformer 10 of this embodiment will be described.
In order to manufacture the leakage transformer 10 of the present embodiment, first, the secondary winding 80 is wound around the secondary winding portion formed between the flange portion 44a and the flange portion 44b, and the flange portion 44b and the flange portion are also wound. The primary winding 70 is wound around the primary winding portion formed between 44c, and both ends of each winding are connected to any one of the terminal portions 42a, 43a, 46a and the binding terminals 43b, 46b.

  Then, the central leg 23 formed in the first core 20 is inserted into the inner peripheral portion of each winding frame portion 40, and the insertion hole 54 provided in the spacer 50 is inserted into the pair of support columns 24 formed in the first core 20. The spacer 50 is attached within the interval between the two winding frame portions 40.

  Further, the second core 30 is positioned above the respective reel portions 40 and the spacers 50 to close the upper open surface of the first core 20.

  Thereafter, an adhesive is injected into the gap 90 formed between the outer peripheral surface of the central leg 23 and the inner peripheral surface of the winding frame portion 40 from the through-hole 33 provided in the second core 30, and the first core 20. The winding frame part 40 and the second core 30 are bonded together. At this time, the entire gap is not filled with the adhesive, but the adhesive hardly adheres above the gap and in the through holes.

<Dissipation of heat generated in the core>
When a current is passed through the primary winding 70 and the secondary winding 80, heat is generated in the windings 70 and 80. Part of this heat is conducted to the first core 20 and the second core 30 and dissipated into the outside air. Further, most of the heat generated in each of the windings 70 and 80 is a gap formed between the outer peripheral surface of the central leg 23 of the first core 20 and the inner peripheral surface of the winding frame portion 40 due to air convection or radiation. Through 90, the light is dissipated outward from the through-hole 33 provided in the second core 30.

  Therefore, the heat generated in the core part is reliably dissipated outside the core part through the through-hole 33, and the heat does not accumulate in the core part, so that the performance as designed can be reliably exhibited, The durability of the transformer can be improved.

  For example, the self-heating when driving a conventional leakage transformer without the through-hole 33 is about 23 ° C., but the self-heating when driving the leakage transformer 10 of the present embodiment with the through-hole 33 is about 21 ° C. As a result, the temperature has dropped by about 2 ° C., and the leakage transformer 10 used in the power supply circuit for electronic equipment such as the power supply circuit for the backlight of the liquid crystal screen has a very effective heat dissipation effect.

<Other embodiments>
In addition, although the 1st core 20 and the 2nd core 30 are formed with the ferrite, it is not restricted to this as a forming material of a core, It is possible to select from other general core materials, For example, it is possible to use materials such as permalloy, sendust, and iron carbonyl, and it is also possible to use a dust core obtained by compression molding these fine powders.

  In this embodiment, the double leakage transformer is provided with two winding frame portions 40. However, the winding frame portion 40 may be applied to one transformer, or three or four winding frame portions. You may apply to the above transformer.

  Furthermore, the use of the transformer according to the present invention is not limited to the leakage transformer 10 and can be applied to other types of transformers.

1 is an exploded perspective view of a leakage transformer according to an embodiment of the present invention. The top view (a) of the leakage transformer which concerns on embodiment of this invention, and AA sectional drawing (b) in a top view (a) The center leg of the 1st core which constitutes the leakage transformer concerning an embodiment of the present invention, and a partial sectional view of a reel part The partial cross section figure which shows other embodiment of the center leg of the 1st core which comprises the leakage transformer which concerns on embodiment of this invention, and a winding frame part

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Leakage transformer 20 1st core 21 Base part 22 Side leg 23 Central leg 24 Support | pillar 25 Tapered surface 30 2nd core 31 Main body 32 Engagement recessed part 33 Through-hole 40 Winding frame part 41 Mount 42a, 43a, 46a Terminal part 43b, 46b Binding terminals 44a to 44c collar 45 taper surface 50 spacer 51 substrate 52 separation plate 53 positioning projection 54 insertion hole 70 primary winding 80 secondary winding 90 gap

Claims (5)

In a transformer that includes a core portion that houses a primary winding and a secondary winding to form a closed magnetic circuit, and performs electromagnetic induction between the primary winding and the secondary winding.
The core portion includes a first core having a pair of side legs erected from a base portion and at least one central leg disposed within a distance between the pair of side legs, and an upper portion of the first core A second core disposed so as to close the open surface;
A bobbin-shaped winding frame for winding the primary winding and the secondary winding is attached to the outer periphery of the central leg,
The second core has at least 1 at a position facing a gap formed between the outer peripheral surface of the central leg and the inner peripheral surface of the winding frame portion when the winding frame portion is attached to the central leg. A transformer having two through holes.   2. The transformer according to claim 1, wherein a gap portion formed between the outer peripheral surface of the central leg and the inner peripheral surface of the winding frame portion is formed so as to increase in diameter upward.   The transformer according to claim 2, wherein the gap portion is increased in diameter upward by forming a taper surface whose diameter is increased upward on an inner peripheral surface of the winding frame portion.   The transformer according to claim 2, wherein the outer peripheral surface of the central leg is a tapered surface having a diameter reduced upward, so that the diameter of the gap portion is increased upward. A manufacturing method of a transformer comprising a core part that houses a primary winding and a secondary winding to form a closed magnetic circuit, and performs electromagnetic induction between the primary winding and the secondary winding,
The core portion includes a first core having a pair of side legs erected from a base portion and at least one central leg disposed within a distance between the pair of side legs, and an upper portion of the first core Forming a second core disposed so as to close the open surface;
A bobbin-shaped winding frame for winding the primary winding and the secondary winding is attached to the outer periphery of the central leg,
The second core has at least 1 at a position facing a gap formed between the outer peripheral surface of the central leg and the inner peripheral surface of the winding frame portion when the winding frame portion is attached to the central leg. Formed so that two through holes are opened,
Thereafter, by injecting an adhesive into a gap formed between the outer peripheral surface of the central leg and the inner peripheral surface of the winding frame portion from the through hole provided in the second core, the first core, A transformer manufacturing method, wherein a winding frame part and the second core are bonded together.

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