JP2012169331A - Transformer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transformer capable of suppressing the temperature rise.SOLUTION: A transformer 1 includes: a core 2 made up of a magnetic material; a primary coil 11; and a secondary coil 12. The core 2 includes a columnar part 20 that is formed into a column shape. The primary coil 11 and the secondary coil 12 are formed by winding a coated conductor 3 (3a, 3b) around the column 20. The primary coil 11 is a spiral coil 6 formed by winding the coated conductor 3a spirally, and the secondary coil 12 is a voluted coil 5 formed by winding the coated conductor 3b volutedly.

Description

  The present invention relates to a transformer having a primary coil and a secondary coil formed by winding a coated conductor.

  Conventionally, as shown in FIG. 13, a core 94 made of a magnetic material, and a primary coil 91 and a secondary coil 92 wound around the core 94, and the primary coil 91 and the secondary coil 92, There is known a transformer 90 that transforms AC voltage between them (see Patent Documents 1 and 2 below).

  The transformer 90 includes a bobbin 93 disposed around a core 94. A primary coil 91 is formed by winding a coated conductor spirally around the bobbin 93. Further, the secondary coil 92 is formed by spirally winding another coated conductor around the outer periphery of the primary coil 91.

  When an AC voltage is applied to the primary coil 91, a voltage obtained by multiplying the AC voltage by a ratio n 2 / n 1 between the number of turns n 1 of the primary coil 91 and the number of turns n 2 of the secondary coil 92 is output from the secondary coil 92. At this time, an alternating current flows through the coils 91 and 92. Since the coated conductors constituting the coils 91 and 92 have electric resistance, the coils 91 and 92 generate heat when an alternating current flows.

JP 2008-159963 A

  However, since the transformer 90 has the secondary coil 92 wound around the outer periphery of the primary coil 91, there is a problem that the distance L from the inner peripheral portion 91a of the primary coil 91 to the coil surface 99 becomes longer. When this distance L becomes long, the resistance heat generated in the inner peripheral portion 91a is likely to be trapped in the coil and it is difficult to radiate heat. Therefore, there arises a problem that the temperature of the inner peripheral portion 91a is likely to rise.

  Further, the transformer 90 has a problem that the contact area between the primary coil 91 and the secondary coil 92 is large because the secondary coil 92 is wound around the outer periphery of the primary coil 91. When the primary coil 91 and the secondary coil 92 are close to each other, a so-called proximity effect is generated in which an alternating current tends to flow in a concentrated portion. When the contact area of the coils 91 and 92 is large, the proximity effect becomes significant and the AC resistance increases. Therefore, there arises a problem that the amount of heat generated when a current is passed increases.

As described above, when the secondary coil 92 is spirally wound around the outer periphery of the primary coil 91 wound spirally, the heat dissipation of the inner peripheral portion 91a is reduced, and the primary coil 91 and the secondary coil 92 are There arises a problem that the calorific value increases due to the proximity effect between the two.
Further, as shown in FIG. 14, both the primary coil 91 and the secondary coil 92 are spirally wound, and the primary coil 91 and the secondary coil 92 are arranged adjacent to each other in the axial direction (X direction). Problem arises. Therefore, a transformer capable of suppressing the temperature rise has been desired.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a transformer capable of suppressing a temperature rise.

The present invention has a columnar portion formed in a columnar shape, and a core made of a magnetic material;
A primary coil and a secondary coil formed by winding a coated conductor around the columnar part,
One of the primary coil and the secondary coil is a spiral coil in which the coated conductor is wound in a spiral shape, and the other coil is a spiral coil in which the coated conductor is wound in a spiral shape. It is in the transformer characterized by being (Claim 1).

  In the transformer, one of the primary coil and the secondary coil is the spiral coil, and the other coil is the spiral coil. Here, the term “spiral coil” means that one end of a coated conductor is provided near the columnar portion, and the coated conductor is wound gradually away from the columnar portion as it goes from the one end to the other end. This means a coil that has been turned. In addition, the term “spiral coil” means a coil in which a coated conductor is wound so as to gradually progress in the axial direction from one end of the coated conductor to the other end. Thus, since the spiral coil and the spiral coil are different in the winding method of the coated conductor, the shape of each other can be greatly changed. For example, the spiral coil can be disk-shaped and the spiral coil can be cylindrical. Therefore, the contact area between the spiral coil and the spiral coil can be minimized even when they are arranged adjacent to each other. Thereby, the contact area to air of a spiral coil and a spiral coil can be increased, respectively, and it becomes possible to improve heat dissipation.

  Further, since the spiral coil and the spiral coil can minimize the contact area with each other, the proximity effect generated between these coils can be suppressed. Therefore, an increase in AC resistance can be suppressed, and the amount of heat generated when a current is passed can be minimized.

  As described above, according to the present invention, a transformer capable of suppressing a temperature rise can be provided.

FIG. 3 is a cross-sectional view of a transformer in the first embodiment. 3 is a perspective view of a holding member in Embodiment 1. FIG. FIG. 3 is an exploded perspective view of a transformer in the first embodiment. FIG. 3 is a perspective view of a transformer in the first embodiment. Sectional drawing of the trans | transformer in Example 2. FIG. Sectional drawing of the trans | transformer in Example 3. FIG. Sectional drawing of the trans | transformer in Example 4. FIG. Sectional drawing of the trans | transformer in Example 5. FIG. Sectional drawing of the trans | transformer in Example 6. FIG. The perspective view of a transformer in Example 6. FIG. Sectional drawing of the trans | transformer in Example 7. FIG. The perspective view of the trans | transformer in Example 7. FIG. Sectional drawing of the trans | transformer in a prior art example. FIG. 14 is a cross-sectional view of a transformer in a conventional example different from FIG. 13.

A preferred embodiment of the present invention described above will be described.
The transformer is used, for example, as a charger for charging a battery mounted on an electric vehicle or a hybrid vehicle using a commercial power source (AC power source).

  In the spiral coil, the surface passing through the center of the coated conductor does not necessarily have to be perpendicular to the columnar portion, and may be, for example, a conical surface. Further, the spiral coil does not necessarily have a cylindrical surface passing through the center of the coated conductor, and may be, for example, a conical surface provided that it does not overlap the surface of the spiral coil. Good.

In the transformer, of the primary coil and the secondary coil, a coil having a large heat generation amount per unit length of the coated conductor is the spiral coil, and a heat generation amount per unit length of the coated conductor is It is preferable that a small number of coils are the spiral coils.
In this case, the total amount of heat generated by combining the spiral coil and the spiral coil can be reduced. That is, when the number of turns is the same, the length of the coated conductor is easier to shorten in the spiral coil than in the spiral coil. Therefore, if a coil with a large amount of heat generation per unit length is made into a spiral coil and a coil with a small amount of heat generation per unit length is made into a spiral coil, a coil with a large amount of heat generation per unit length is made into a short coated conductor. It is possible to reduce the amount of heat generated in the entire coil. Therefore, the temperature rise of the transformer can be more effectively suppressed.

The spiral coil includes a first spiral portion and a second spiral portion in which the coated conducting wire is spirally wound around the columnar portion, the first spiral portion and the second spiral shape. It is preferable that the portion is disposed so as to face the columnar portion at a predetermined interval in the axial direction.
In this case, since the spiral coil includes the first spiral portion and the second spiral portion, the number of turns of the spiral coil can be increased. In addition, since the first spiral portion and the second spiral portion are arranged to face each other at a predetermined interval in the axial direction, the contact area of the first spiral portion and the second spiral portion with the air Can be increased. Therefore, it becomes possible to improve the heat dissipation of the spiral coil. Further, when the first spiral portion and the second spiral portion are arranged to face each other at a predetermined interval, the proximity effect between them can be reduced, so that the AC resistance of the entire spiral coil can be reduced, and the current flows. The amount of heat generated can be reduced.

The spiral coil includes a first spiral portion and a second spiral portion having different radii, and the first spiral portion and the second spiral portion are arranged in a radial direction of the spiral coil. It is preferable that they are arranged concentrically at a predetermined interval.
In this case, since the spiral coil includes the first spiral portion and the second spiral portion, the number of turns of the spiral coil can be increased. In addition, since the first spiral portion and the second spiral portion are arranged concentrically at a predetermined interval in the radial direction, the air flows between the first spiral portion and the second spiral portion. The contact area can be increased. Therefore, it becomes possible to improve the heat dissipation of the spiral coil. Further, if the first spiral portion and the second spiral portion are arranged concentrically at a predetermined interval, the proximity effect between them can be reduced, so that the AC resistance of the entire spiral coil can be reduced, The amount of heat generated when a current is passed can be reduced.

Further, the primary coil or the secondary coil is positioned adjacent to the spiral coil in the radial direction of the spiral coil and adjacent to the spiral coil in the axial direction of the columnar portion. It is preferable that a heat dissipating member for dissipating the heat generated from the coil is disposed.
In this case, since the heat generated from the primary coil or the secondary coil can be radiated by the heat radiating member, the temperature rise of the transformer can be further effectively suppressed.

In addition, the columnar portion is oriented in the vertical direction, and at least a part of the spiral coil is formed on the upper side in the vertical direction of the spiral coil, and the coated conductor becomes more radially outward of the spiral coil. Is preferably wound so as to be positioned on the upper side in the vertical direction (claim 6).
In this case, the air warmed by the heat generation of the spiral coil rises upward in the vertical direction by convection, and easily moves radially outward along the lower surface of the spiral coil. Therefore, it is possible to prevent warmed air from staying in the vicinity of the center of the coil, and to effectively prevent an increase in the temperature of the transformer.

Example 1
A transformer according to an embodiment of the present invention will be described with reference to FIGS.
The transformer 1 of this example includes a core 2 made of a magnetic material, a primary coil 11, and a secondary coil 12. The core 2 has a columnar portion 20 formed in a columnar shape. The primary coil 11 and the secondary coil 12 are formed by winding the coated conductor 3 (3a, 3b) around the columnar portion 20.
The primary coil 11 is a spiral coil 6 in which the coated conductor 3a is spirally wound, and the secondary coil 12 is a spiral coil 5 in which the coated conductor 3b is spirally wound.

  As shown in FIG. 3, the core 2 includes a first portion 2a disposed on one side in the X direction and a second portion 2b disposed on the other side in the X direction. The first portion 2a and the second portion 2b are composed of a plate-like main body portion 23 that is substantially rectangular in a plan view in the X direction, and a pair of side wall portions 21 and 22 that protrude from both ends of the main body portion 23 in the X direction. With. The columnar portion 20 protrudes from the inner main surface 230 of the main body portion 23 in the same direction as the protruding direction of the side wall portions 21 and 22. The columnar part 20 is formed in a columnar shape. Inner side surfaces 210 and 220 of the side wall portions 21 and 22 are formed in an arc shape so as to accommodate the primary coil 11 and the secondary coil 12.

  As shown in FIG. 1, in the core 2, one side wall portion 21 a, 21 b abuts on the end surface 215, the other side wall portion 22 a, 22 b abuts on the end surface 225, and the columnar portions 20 a, 20 b abut on the front end surface 201. In this state, the first portion 2a and the second portion 2b are combined. In a state where the first portion 2a and the second portion 2b are combined, the length in the X direction from the inner main surface 230a of the first portion 2a to the inner main surface 230b of the second portion 2b is a holding member which will be described later. 4 is slightly longer than the length in the X direction.

  As shown in FIGS. 1 and 4, when the first portion 2 a and the second portion 2 b of the core 2 are combined, they are held by the holding member 4 by the main body portions 23 a and 23 b and the pair of side wall portions 21 and 22. A housing space S for housing the primary coil 11 and the secondary coil 12 is formed.

  As shown in FIG. 3, the core 2 has a pair of openings 25 between the side walls 21 and 22. As shown in FIG. 4, in a state where the first portion 2a and the second portion 2b of the core 2 are combined, the openings 25a and 25b are rectangular. When the primary coil 11 and the secondary coil 12 held by the holding member 4 are sandwiched between the first portion 2a and the second portion 2b and stored in the storage space S, the secondary coil 12 and a part of the holding member 4 are Project from the opening 25. The storage space S communicates with the external space at the opening 25. Therefore, when a current flows through the primary coil 11 and the secondary coil 12 and the air in the storage space S is warmed by heat generated by electrical resistance, the warmed air exits to the external space through the opening 25. Can be done.

  As shown in FIG. 2, the holding member 4 includes a cylindrical portion 48 and two flange portions 40 (40 a and 40 b) that protrude in the radial direction (Y direction) from the cylindrical portion 48. The columnar portion 20 (see FIG. 1) of the core 2 is fitted into the inside 49 of the cylindrical portion 48. The flange portions 40 are each formed in a disk shape. The first flange portion 40 a is formed at one end of the cylindrical portion 48 in the X direction. Further, the second flange portion 40 b is formed at the other end portion in the X direction of the cylindrical portion 48. The holding member 4 is a molded product made of a resin material.

  As shown in FIG. 1, the plate thickness of the first flange portion 40a, the plate thickness of the second flange portion 40b, and the thickness of the cylindrical portion 48 in the Y direction are substantially the same. Further, the plate thickness of the first flange portion 40 a and the second flange portion 40 b is thinner than the plate thickness of the main body portion 23 of the core 2.

In this example, the primary coil 11 and the secondary coil 12 are formed using the covered conducting wire 3 having a circular cross section. The diameter of the covered conductor 3a constituting the primary coil 11 and the diameter of the covered conductor 3b constituting the secondary coil 12 are substantially the same.
The covered conducting wire 3 does not necessarily have a circular cross section, and may have an arbitrary shape such as a square cross section or a rectangular cross section.

  As described above, the primary coil 11 is the spiral coil 6, and the secondary coil 12 is the spiral coil 5. As shown in FIG. 1, the primary coil 11 is formed by winding the coated conducting wire 3 a in a spiral shape along the outer peripheral surface of the cylindrical portion 48. The secondary coil 12 is formed by winding the covered conducting wire 3b in a spiral shape so as to contact the main surface 400a of the first flange portion 40a opposite to the main body portion 23a side of the core 2.

  The “spiral coil 5” is provided such that one end of the coated conductor 3b is provided in the vicinity of the columnar portion 20 and gradually becomes farther from the columnar portion 20 as it goes from the one end to the other end. Means a coil in which the coated conductor 3b is wound. In this example, the spiral coil 5 is formed in a disc shape by winding the coated conducting wire 3b in a plane P1 orthogonal to the X direction.

  Further, the “spiral coil 6” means a coil in which the coated conductor 3a is wound so as to progress gradually in the axial direction (X direction) from one end of the coated conductor 3a toward the other end. To do. In this example, the spiral coil 6 is formed in a cylindrical shape centered on the columnar portion 20.

  In this example, when the primary coil 11 and the secondary coil 12 are compared, the primary coil 11 generates more heat per unit length of the coated conductor 3. The primary coil 11 having a large amount of heat generation per unit length is a spiral coil 6, and the secondary coil 12 having a small amount of heat generation per unit length of the coated conductor 3 is a spiral coil 5.

  When the secondary coil 12 generates a larger amount of heat per unit length of the coated conductor 3, the secondary coil 12 is a helical coil 6 and the primary coil 11 with a smaller amount of heat generated per unit length is used. A spiral coil 5 is preferable.

  The effect of this example will be described. In the transformer 1 of this example, one of the primary coil 11 and the secondary coil 12 is a spiral coil 5 and the other coil is a spiral coil 6. Since the spiral coil 5 and the spiral coil 6 are different in the winding method of the coated conductor 3, the mutual shape can be greatly changed. For example, as shown in FIGS. 1 to 4, the spiral coil 5 can be formed into a disk shape, and the spiral coil 6 can be formed into a cylindrical shape. Therefore, even when the spiral coil 5 and the spiral coil 6 are arranged adjacent to each other, the contact area with each other can be minimized. Thereby, the contact area to the air of the spiral coil 5 and the spiral coil 6 can be increased, respectively, and the heat dissipation can be improved.

  Further, since the spiral coil 6 and the spiral coil 5 can minimize the contact area with each other, the proximity effect generated between the coils 5 and 6 can be suppressed. Therefore, an increase in AC resistance can be suppressed, and the amount of heat generated when a current is passed can be minimized.

  Moreover, in this example, the coil (primary coil 11) with a large calorific value per unit length of the covered conductor 3 among the primary coil 11 and the secondary coil 12 is the helical coil 6, and the unit length of the covered conductor 3 is set. The coil (secondary coil 12) with a small amount of heat generated per unit is used as the spiral coil 5. If it does in this way, the whole emitted-heat amount which combined the spiral coil 6 and the spiral coil 5 can be reduced. That is, when the number of turns is the same, the helical coil 6 is easier to shorten the length of the covered conducting wire 3 than the spiral coil 5. Therefore, if the coil (primary coil 11) with a large amount of heat generation per unit length is a spiral coil 6 and the coil (secondary coil 12) with a small amount of heat generation per unit length is a spiral coil 5, the unit A coil (primary coil 11) having a large amount of heat generation per length can be formed by the short covered conductor 3, and the heat generation amount of the entire coil can be reduced. Therefore, the temperature rise of the transformer 1 can be more effectively suppressed.

  As described above, according to this example, it is possible to provide the transformer 1 that can suppress the temperature rise.

(Example 2)
In this example, the shapes of the spiral coil 6 and the spiral coil 5 are changed. As shown in FIG. 5, in this example, the spiral coil 5 is inclined with respect to the plane P <b> 1 perpendicular to the columnar part 20. That is, the surface P2 passing through the center of the covered conductor 3b constituting the spiral coil 5 is a conical surface P2. The angle θ1 formed by the plane P1 and the conical surface P2 is more preferably 0 ° <θ1 <45 °, and more preferably 0 ° <θ1 <22.5 °.

In this example, as shown in FIG. 5, the spiral coil 6 is inclined with respect to the cylindrical surface P <b> 3 centering on the columnar portion 20. That is, the surface passing through the center of the covered conducting wire 3a constituting the spiral coil 6 is a conical surface P4. The angle θ2 formed by the cylindrical surface P3 and the conical surface P4 is more preferably 0 ° <θ2 <45 °, and further preferably 0 ° <θ2 <22.5 °.
In this example, the angle θ3 formed between the conical surface P2 and the conical surface P4 is 90 ° or more.
In addition, the same configuration as that of the first embodiment is provided.

The effect of this example will be described. In this example, since the surfaces P2 and P4 passing through the centers of the coated conducting wires 3a and 3b are conical surfaces, the degree of freedom in designing the spiral coil 5 and the spiral coil 6 can be increased. In this example, since the angle θ3 formed by the conical surface P2 and the conical surface P4 is 90 ° or more, the heat dissipation of the spiral coil 5 and the helical coil 6 can be improved.
In addition, the same functions and effects as those of the first embodiment are provided.

(Example 3)
In this example, the spiral coil 5 and the spiral coil 6 are laminated in a plurality of layers. As shown in FIG. 6, the spiral coil 5 of this example is laminated in two stages in the X direction. Further, the spiral coil 6 of this example is laminated in two stages in the Y direction.
Thus, when the spiral coil 5 or the spiral coil 6 is laminated in a plurality of stages, the number of turns of the respective coils 5 and 6 can be increased. The number of layers of the coils 5 and 6 is not limited to two, but can be three or more. However, if the number of layers is increased too much, the heat dissipation performance of the coils 5 and 6 is lowered. Is preferred.
In addition, the configuration and operational effects similar to those of the first embodiment are provided.

Example 4
In this example, the shape of the spiral coil 5 is changed. As shown in FIG. 7, the spiral coil 5 of this example includes a first spiral portion 51 and a second spiral portion 52 in which the coated conductor 3 b is spirally wound around the columnar portion 20. The first spiral portion 51 and the second spiral portion 52 are disposed to face each other at a predetermined interval in the X-ray direction. The 1st spiral part 51 and the 2nd spiral part 52 consist of one covered conducting wire 3b. The first spiral portion 51 is wound so as to contact the main surface 400a of the first flange portion 40a opposite to the main body portion 23a side of the core 2. The second spiral portion 52 is wound so as to come into contact with the main surface 400b of the second flange portion 40b opposite to the main body portion 23b side of the core 2.
In addition, the same configuration as that of the first embodiment is provided.

The effect of this example will be described. In this example, since the spiral coil 5 includes the first spiral portion 51 and the second spiral portion 52, the number of turns of the spiral coil 5 can be increased. Further, since the first spiral portion 51 and the second spiral portion 52 are arranged to face each other at a predetermined interval in the X direction, the air between the first spiral portion 51 and the second spiral portion 52 The contact area can be increased. Therefore, the heat dissipation of the spiral coil 5 can be improved. Further, if the first spiral part 51 and the second spiral part 52 are arranged at a predetermined interval, the proximity effect between them can be reduced, so that the AC resistance of the entire spiral coil 5 can be reduced, and the current It is possible to reduce the amount of heat generated when flowing.
In addition, the same functions and effects as those of the first embodiment are provided.

(Example 5)
In this example, the shape of the spiral coil 6 is changed. As shown in FIG. 8, the spiral coil 6 of this example includes a first spiral portion 61 and a second spiral portion 62 having different radii. The first spiral portion 61 and the second spiral portion 62 are arranged concentrically at a predetermined interval in the Y direction of the spiral coil 6. The first spiral portion 61 and the second spiral portion 62 are composed of a single covered conductor 3a. The first spiral portion 61 is wound so as to contact the outer peripheral surface of the cylindrical portion 48 of the holding member 4. Further, the cylindrical member 45 is fitted to the first flange portion 40 a and the second flange portion 40 b of the holding member 4. A second spiral portion 62 is spirally wound around the outer peripheral surface of the cylindrical member 45.

The effect of this example will be described. In this example, since the spiral coil 6 includes the first spiral portion 61 and the second spiral portion 62, the number of turns of the spiral coil 6 can be increased. Further, since the first spiral portion 61 and the second spiral portion 62 are concentrically arranged at a predetermined interval in the Y direction, the first spiral portion 61 and the second spiral portion 62 The area of contact with air can be increased. Therefore, the heat dissipation of the spiral coil 6 can be improved. Further, if the first spiral portion 61 and the second spiral portion 62 are arranged at a predetermined interval, the proximity effect between them can be reduced, so that the AC resistance of the entire spiral coil 6 can be reduced, and the current can be reduced. It is possible to reduce the amount of heat generated when flowing.
In addition, the same functions and effects as those of the first embodiment are provided.

(Example 6)
In this example, as shown in FIG. 9, the heat radiating member 7 is provided in the core 2. In this example, the position is adjacent to the spiral coil 6 in the Y direction and adjacent to the spiral coil 5 (the first spiral portion 51 and the second spiral portion 52) in the X direction. The heat radiating member 7 is arranged. The heat radiating member 7 is configured to radiate heat generated from the primary coil 11 or the secondary coil 12. Similar to the fourth embodiment, the spiral coil 5 includes a first spiral portion 51 and a second spiral portion 52. Further, the spiral coil 6 does not include the second spiral portion 62 (see FIG. 8).

The heat radiating member 7 is obtained by winding a sheet-like member made of a material having high thermal conductivity such as silicon gel around the outer surface of the spiral coil 6. The heat radiating member 7 is in contact with the spiral coil 6, the first spiral portion 51, and the second spiral portion 52. Further, as shown in FIG. 10, a part of the heat radiating member 7 projects out of the core 2 from the openings 25 a and 25 b of the core 2. A part of the secondary coil 12 and a part of the holding member 4 also protrude out of the core 2 from the openings 25a and 25b. When a current is passed through the primary coil 11 and the secondary coil 12, heat is generated from these coils 11 and 12. This heat is transferred to the heat radiating member 7 and further transferred from the surface 70 of the heat radiating member 7 to the air outside the core 2. Thereby, it is comprised so that the heat | fever of the coils 11 and 12 may be thermally radiated.
In addition, the same configuration as that of the first embodiment is provided.

The effect of this example will be described. In this example, since the heat generated from the primary coil 11 or the secondary coil 12 can be radiated by the heat radiating member 7, the temperature rise of the transformer 1 can be further effectively suppressed.
In addition, the same functions and effects as those of the first embodiment are provided.

(Example 7)
In this example, the shape of the spiral coil 5 is changed. As shown in FIGS. 11 and 12, the columnar portion 20 of this example faces the vertical direction (V direction). The spiral coil 5 includes a first spiral portion 51 and a second spiral portion 52 as in the fourth embodiment. The first spiral portion 51 is formed above the spiral coil 6 in the vertical direction (V direction). The first spiral portion 51 is wound so that the coated conductor 3 is positioned on the upper side in the vertical direction (V direction) as it goes outward in the radial direction (Y direction).

The core 2 includes a first portion 2a and a second portion 2b as in the first embodiment. The main body portion 23a of the first portion 2a is formed in a conical shape that protrudes downward in the vertical direction (V direction). A pair of side wall portions 21a, 22a protrudes downward in the vertical direction (V direction) from both ends of the conical body portion 23a. Moreover, the column part 20a protrudes from the center of the main-body part 23a in the same direction as the side wall parts 21a and 22a.
Similar to the first embodiment, the second portion 2b includes a plate-like main body portion 23b. A pair of side wall portions 21b, 22b protrudes upward in the vertical direction from both ends of the main body portion 23b. Further, the column part 20b protrudes from the center of the main body part 23b in the same direction as the side wall parts 21b and 22b.

  The first flange portion 40a of the holding member 4 is formed in a conical shape that protrudes downward in the vertical direction (V direction). Moreover, the 2nd flange part 40b is formed in flat form similarly to Example 1. FIG. The first spiral portion 51 is formed by winding the covered conducting wire 3b so as to come into contact with the main surface 400a of the first flange portion 40a formed in a conical shape on the opposite side to the main body portion 23a side of the core 2. Has been. The angle θ4 formed by the conical surface P2 passing through the center of the coated conductor 3b and the horizontal plane P1 is preferably 0 ° <θ4 <45 °, and more preferably 0 ° <θ4 <22.5 °.

  As shown in FIG. 11, the first portion 2a and the second portion 2b are assembled with the pair of side wall portions 21 and 22 in contact with each other at the end surfaces 215 and 225 and the columnar portions 20a and 20b in contact with each other at the tip surface 201. It has been found. A storage space S for storing the primary coil 11 and the secondary coil 12 held by the holding member 4 is formed by the pair of side wall portions 21 and 22 and the main body portions 23a and 23b. The storage space S communicates with the external space through a pair of openings 25a and 25b (see FIG. 12) formed in the core 2.

When a current is passed through the primary coil 11 and the secondary coil 12, heat is generated and the surrounding air 8 is warmed. The warmed air 8 rises upward in the vertical direction by convection, and moves outward in the radial direction (Y direction) along the lower surface of the spiral coil 5. And it goes out to external space through opening part 25a, 25b. Instead, the cooled air flows into the storage space S from the openings 25a and 25b. Thereby, the coils 11 and 12 can be cooled.
In addition, the same configuration as that of the first embodiment is provided.

The effect of this example will be described.
With the above configuration, the air 8 warmed by the heat generated by the coils 11 and 12 rises upward in the vertical direction (V direction) by convection, and extends radially outward (Y direction) along the lower surface of the spiral coil 5. It becomes easy to move. Moreover, since the storage space S of the core 2 communicates with the external space at the openings 25a and 25b, the warmed air 8 can be effectively discharged to the outside of the core 2. Therefore, it is possible to prevent the heated air 8 from staying near the centers of the coils 11 and 12 and to prevent the temperature of the transformer 1 from rising.
In addition, the same functions and effects as those of the first embodiment are provided.

DESCRIPTION OF SYMBOLS 1 Transformer 11 Primary coil 12 Secondary coil 2 Core 3 Coated conducting wire 4 Holding member 5 Spiral coil 6 Spiral coil 7 Heat dissipation member

Claims (6)

Having a columnar part formed in a columnar shape, and a core made of a magnetic material;
A primary coil and a secondary coil formed by winding a coated conductor around the columnar part,
One of the primary coil and the secondary coil is a spiral coil in which the coated conductor is wound in a spiral shape, and the other coil is a spiral coil in which the coated conductor is wound in a spiral shape. Transformer characterized by being.   2. The transformer according to claim 1, wherein, among the primary coil and the secondary coil, a coil that generates a large amount of heat per unit length of the coated conductor is the helical coil, and a unit length of the coated conductor. A transformer characterized in that a coil having a small amount of heat generation per unit is the spiral coil.   3. The transformer according to claim 1, wherein the spiral coil includes a first spiral portion and a second spiral portion in which the coated conducting wire is spirally wound around the columnar portion, The first spiral part and the second spiral part are arranged to face each other at a predetermined interval in the axial direction of the columnar part.   4. The transformer according to claim 1, wherein the spiral coil includes a first spiral portion and a second spiral portion having different radii, and the first spiral portion and the spiral portion The second spiral portion is a transformer characterized in that the second spiral portion is arranged concentrically at a predetermined interval in the radial direction of the spiral coil.   5. The transformer according to claim 1, wherein the position is adjacent to the spiral coil in a radial direction of the spiral coil, and the columnar portion with respect to the spiral coil. A transformer, wherein a heat radiating member for radiating heat generated from the primary coil or the secondary coil is disposed at a position adjacent to each other in the axial direction.   5. The transformer according to claim 1, wherein the columnar portion is oriented in a vertical direction, and at least a part of the spiral coil is formed on a vertical upper side of the spiral coil. The transformer is characterized in that the covered conducting wire is wound so as to be positioned on the upper side in the vertical direction toward the radially outer side of the spiral coil.

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