JP6089824B2 - Trance - Google Patents

Description

  The present invention relates to a transformer including a core, a primary coil, and a secondary coil.

  As a transformer for transforming an alternating voltage, a first core and a second core made of a magnetic material, a primary coil, and a secondary coil are provided, and the first core and the second core are combined to form one core. Is known (see Patent Document 1 below). The first core and the second core are combined so as to sandwich the primary coil and the secondary coil from both sides in the axial direction.

  The first core and the second core each have an inner pole, an outer pole, and a base portion for connecting them. The inner poles are arranged inside the primary coil and the secondary coil, and are opposed to each other while providing a gap for preventing magnetic saturation. Further, the outer pole is disposed outside the primary coil and the secondary coil, and is in contact with each other.

  At least one of the first core and the second core is composed of two or more core pieces. Each core piece includes the inner pole, the outer pole, and the base portion.

  Of the primary coil and the secondary coil, a coil through which a large current flows is formed of a bus bar or the like, and has an outer diameter larger than that of a coil with a small current. If a wide gap is formed between the coil having a large outer diameter (large-diameter coil) and the outer pole, the cross-sectional area of the core is reduced, which causes a problem that the core is easily increased in size. Therefore, the side surface of the outer pole is formed in a curved shape along the outer peripheral edge of the large diameter coil, and the formation of a wide gap between the outer pole and the large diameter coil is suppressed.

JP 2010-93153 A

  However, if the side surface of the outer pole is curved, the portions at both ends of the side surface are likely to have acute angles (see FIG. 13). Moreover, since the core piece is held in a state where only the outer poles are in contact with each other while providing a gap between two opposing inner poles, when a vibration or impact is applied from the outside, The core piece may swing. At this time, the core piece swings around the acute angle part as a fulcrum. Therefore, there is a possibility that a large stress is applied to the part having an acute angle and this part is missing.

  The present invention has been made in view of such a background, and an object of the present invention is to provide a transformer in which the core can be reduced in size and the outer pole is not easily chipped even when the core piece swings.

One aspect of the present invention is a transformer including a core made of a soft magnetic material, a primary coil, and a secondary coil,
The core comprises a first core and a second core arranged so as to sandwich the primary coil and the secondary coil from both sides in the axial direction,
The first core and the second core are disposed on the inner side of the primary coil and the secondary coil and face each other while providing a gap therebetween, and on the outer side of the primary coil and the secondary coil. An outer pole arranged and abutting each other, and a base portion for connecting the inner pole and the outer pole,
At least one of the first core and the second core is composed of two or more core pieces, and each core piece includes the inner pole, the outer pole, and the base portion.
The contact surface with which the outer poles contact each other is a large coil having a larger outer diameter of the primary coil and the secondary coil on the inner pole side when viewed from the axial direction. A curved portion that is curved along the outer peripheral edge of the radial coil, and a linear portion that is linearly formed,
In the normal direction, which is a direction parallel to the contact surface and perpendicular to the linear portion, the linear portion is closer to the inner pole than any portion of the curved portion, or to the curved portion. It is formed at the same position as the part closest to the inner pole ,
The outer pole includes a curved surface curved along the curved portion as a side surface on the inner pole side, and a flat surface connected to the curved surface, and a C surface is provided between the flat surface and the contact surface. The transformer is characterized in that a chamfered portion formed of a surface or a rounded surface is formed, and the linear portion is formed at a boundary between the chamfered portion and the contact surface .

In the transformer, the curved portion and the straight portion are formed on the inner pole side of the contact surface of the outer pole. The straight portion is formed in the normal direction in the position closer to the inner pole than any portion of the bending portion, or in the same position as the portion of the bending portion closest to the inner pole.
Therefore, the core can be reduced in size, and the outer pole can be made difficult to chip even if the core piece swings. That is, since the said trans | transformer has formed the said curved part in the outer pole, the clearance gap between an outer pole and a large diameter coil can be made small. Therefore, the core can be reduced in size. Moreover, since the said linear part is formed in the outer pole, the said transformer can be rock | fluctuated centering on this linear part, when a core piece rock | fluctuates. That is, when the core piece swings, the two outer poles facing each other can be brought into contact with each other at the straight portion, and contact with one point can be prevented. Therefore, even if the core piece swings, a large stress is not easily applied to the outer pole, and the outer pole is less likely to be chipped.

  As described above, it is possible to provide a transformer in which the core can be reduced in size and the outer pole is not easily chipped even when the core piece swings.

FIG. 4 is an exploded perspective view of a transformer in Reference Example 1. FIG. 5 is a partial perspective plan view of a transformer in Reference Example 1, in which a holder is omitted. The principal part enlarged view of FIG. FIG. 4 is an enlarged plan view of a second core and a secondary coil in Reference Example 1, and a diagram in which a holder is omitted. The principal part enlarged view of FIG. The side view of the combined core piece in the reference example 1. FIG. It is a side view of the combined core piece in the reference example 1, Comprising: The figure in the state which the upper core piece rock | fluctuated. FIG. 10 is a partially transparent plan view of a transformer in Reference Example 2 and a diagram in which a holder is omitted. The enlarged plan view of the 2nd core and secondary coil in Example 1. FIG. The side view of the combined core piece in Example 1. FIG. The principal part expanded side view of the core which made the chamfered part the round surface in Example 1. FIG. FIG. 10 is an exploded perspective view of a transformer in Reference Example 3 . FIG. 6 is a partial perspective plan view of a transformer in Comparative Example 1.

  The transformer may be a vehicle-mounted transformer mounted on a vehicle such as an electric vehicle or a hybrid vehicle.

In the transformer, it is preferable that the outer pole has two straight portions, and the straight portions are connected to both ends of the curved portion, respectively.
In this case, since two straight portions are formed, the stress applied to the outer pole when the core piece swings can be received by the two straight portions. Therefore, it is possible to reduce the stress applied to each linear portion, and to more effectively suppress the outer pole from being lost.

Moreover, it is preferable that the said base | substrate part has the shape where the length in the width direction which is a direction parallel to the said linear part becomes short gradually toward the said inner pole from the said outer pole in the said normal line direction. (Claim 3).
In this case, since the center of gravity of the core piece is present at a position close to the outer pole, the core piece is less likely to swing. Therefore, it becomes easier to suppress the lack of the outer pole.

The core piece preferably has a maximum length in the width direction shorter than a maximum length in the normal direction.
In this case, the core can be formed in an elongated shape and can be reduced in size. As a result, the overall shape of the transformer can be elongated and the size can be reduced.
The transformer is used as a component such as a DC-DC converter together with other electronic components. When the transformer is elongated and downsized, when the other electronic component and the transformer are arranged adjacent to each other, only the transformer does not need to be extremely wider than the other electronic components. For this reason, a so-called dead space is hardly generated in the DC-DC converter, and the layout of components can be easily designed.

( Reference Example 1)
A reference example relating to the transformer will be described with reference to FIGS. As shown in FIGS. 1 to 3, the transformer 1 of this example includes a core 2 made of a soft magnetic material, a primary coil 11, and a secondary coil 12.
The core 2 includes a first core 2a and a second core 2b. The first core 2a and the second core 2b are arranged so as to sandwich the primary coil 11 and the secondary coil 12 from both sides in the axial direction (Z direction).

  The first core 2a and the second core 2b each include an inner pole 3, an outer pole 4, and a base portion 5. Each inner pole 3 is arranged inside the primary coil 11 and the secondary coil 12 and faces each other while providing a gap G (see FIG. 6) between them. Moreover, each outer pole 4 is distribute | arranged to the outer side of the primary coil 11 and the secondary coil 12, and is mutually contact | abutting (refer FIG. 6). The base portion 5 connects the inner pole 3 and the outer pole 4.

As shown in FIG. 1, the first core 2 a and the second core 2 b include two core pieces 20. Each core piece 20 includes one inner pole 3, one outer pole 4, and one base portion 5.
As shown in FIGS. 1 to 3, the abutment surface 40 with which the outer pole 4 abuts has a curved portion 42 and a straight portion 41 on the side 43 on the inner pole 3 side when viewed from the Z direction. The bending portion 42 is bent along the outer peripheral edge 130 of the large-diameter coil 13 that is the coil having the larger outer diameter of the primary coil 11 and the secondary coil 12. Moreover, the linear part 41 is formed in linear form.

  In the normal direction (X direction) that is a direction parallel to the contact surface 40 and perpendicular to the straight portion 41, the straight portion 41 is closer to the inner pole 3 side than any portion of the curved portion 42, or The curved portion 42 is formed at a position equivalent to the portion closest to the inner pole 3.

  The transformer 1 of this example is an on-vehicle transformer to be mounted on a vehicle such as an electric vehicle or a hybrid vehicle.

  Moreover, the transformer 1 of this example is used for a DC-DC converter. This DC-DC converter is provided for stepping down the voltage of the high-voltage DC power source mounted on the vehicle and charging the low-voltage DC power source.

  A high voltage AC voltage is applied to the primary coil 11, and the secondary coil 12 outputs a low voltage AC voltage. As shown in FIGS. 1 and 2, the secondary coil 12 is formed of a bus bar so that a large current flows compared to the primary coil 11, so that heat generation by the current can be suppressed. Further, the secondary coil 12 has an outer diameter larger than that of the primary coil 11. That is, in this example, the secondary coil 12 is the large-diameter coil 13. Since the primary coil 11 has a small amount of flowing current, it is formed using a thin conducting wire. The primary coil 11 is configured by winding a conducting wire around a resin bobbin (not shown).

  The input terminal 110 of the primary coil 11 and the output terminal 120 of the secondary coil 12 each protrude on the same side in the width direction (Y direction) parallel to the straight line portion 41. Further, the center tap 121 of the secondary coil 12 protrudes on the opposite side to the protruding side of the output terminal 120 in the Y direction.

  The primary coil 11 and the secondary coil 12 are overlapped in the Z direction and are inserted into the gap S between the inner pole 3 and the outer pole 4.

  As shown in FIG. 1, the first core 2 a and the second core 2 b of this example are each composed of two core pieces 20. The core piece 20 is made of ferrite. As described above, each core piece 20 has one base portion 5, one inner pole 3, and one outer pole 4. In this example, one core piece 20a of the first core 2a and one core piece 20c of the second core 2b are in contact with each other by the outer poles 4 and a gap G (see FIG. 6) between the inner poles 3 Reference) is formed. The contact surface 40 of the outer pole 4 is polished. Further, the other core piece 20b of the first core 2a and the other core piece 20d of the second core 2b are combined in the same manner.

  As shown in FIG. 3, the side surface 490 of the outer pole 4 on the inner pole 3 side has a curved surface 420 that is curved along the outer peripheral edge 130 of the large-diameter coil 13 (secondary coil 12), and a flat surface 410. Is formed. The side formed by the curved surface 420 and the contact surface 40 is the curved portion 42, and the side formed by the flat surface 410 and the contact surface 40 is the linear portion 41.

  As shown in FIGS. 4 and 5, the distance between the outer peripheral edge 130 of the large-diameter coil 13 and the side surface 490 of the outer pole 4 is narrow on the curved surface 420 and wide on the flat surface 410.

  Further, as shown in FIG. 4, the outer pole 4 of this example has two straight portions 41. The straight portions 41 are connected to both ends of the curved portion 42, respectively.

  Further, as shown in FIG. 4, the base portion 5 of this example has a shape in which the length in the Y direction is gradually shortened from the outer pole 4 to the inner pole 3 in the X direction. More specifically, the base portion 5 has a constant length in the Y direction while traveling a predetermined distance d from the outer pole 4 to the inner pole 3 in the X direction. And after passing the predetermined distance d, it is formed so that the length of a Y direction may become short gradually as it goes to the outer surface 35 of the inner pole 3. FIG.

  As shown in FIG. 6, the core piece 20c constituting the second core 2b (see FIG. 1) is placed on the bottom wall 15 of the case of the DC-DC converter. Between the bottom wall 15 and the core piece 20c, a heat radiating sheet (not shown), heat radiating grease, a noise reducing sheet, and the like are interposed. The core piece 20a which comprises the 1st core 2a (refer FIG. 1) is distribute | arranged to the perpendicular direction upper direction with respect to the core piece 20c of the 2nd core 2b. Further, in this example, the two core pieces 20a and 20c are integrated with the two core pieces 20a and 20c sandwiched by the holder 14 and the contact surfaces 40 of the outer pole 4 are in close contact with each other.

  The holder 14 includes a first portion 141 that extends in the Z direction, a second portion 142 that presses the upper core piece 20a toward the bottom wall 15, and a third portion 143 that engages with the groove portion 200 of the lower core piece 20c. And a fourth portion 144 extending from the first portion 141 in the X direction. Two core pieces 20a, 20c are sandwiched between the second portion 142 and the third portion 143. Further, a bolt 55 is inserted into a through hole 550 formed in the fourth portion 144 and screwed into the screw hole 151 of the bottom wall 15. As a result, the two core pieces 20 a and 20 c are fixed to the bottom wall 15.

  As shown in FIG. 6, a gap G is formed between the two inner poles 3 in a state where the two core pieces 20 a and 20 c are sandwiched by the holder 14. By forming the gap G in this way, the magnetic flux generated from the primary coil 11 or the secondary coil 12 is prevented from being saturated inside the core pieces 20a and 20c.

  Although not shown, the other core piece 20b of the first core 2a (see FIG. 1) and the other core piece 20d of the second core 2b are similarly held by the holder 14 and fixed to the bottom wall 15. The

  As described above, in this example, in order to bring the outer poles 4 into close contact with each other while forming the gap G, only the portion of the upper core piece 20a where the outer pole 4 is formed is pressed toward the bottom wall 15 side. The part where the pole 3 is formed is not pressed. Therefore, as shown in FIG. 7, the upper core piece 20a may swing in a direction in which the two inner poles 3 come into contact with each other when an impact or vibration is applied from the outside. At this time, the upper core piece 20a swings around the straight portion 41 as the central axis. That is, the upper core piece 20a swings in a state where the two outer poles 4 are in contact with each other at the straight portion 41.

The effect of this example will be described. As shown in FIGS. 1 and 2, in this example, a curved portion 42 and a straight portion 41 are formed on a side 43 on the inner pole 3 side of the contact surface 40 of the outer pole 4. The straight portion 41 is formed in the X direction at a position equivalent to the portion closer to the inner pole 3 than the portion of the curved portion 42 or the portion of the curved portion 42 closest to the inner pole 3.
Therefore, the core 2 can be reduced in size, and even if the core piece 20 swings, the outer pole 4 can be made difficult to chip. That is, in this example, since the curved part 42 is formed in the outer pole 4, the clearance gap between the outer pole 4 and the large diameter coil 13 can be made small. Therefore, the core 2 can be reduced in size.

  Further, in this example, since the straight portion 41 is formed on the outer pole 4, as shown in FIG. 7, when the core piece 20 is swung, it can be swung around the straight portion 41. That is, when the core piece 20 swings, the two outer poles 4 facing each other can be brought into contact with each other at the linear portion 41, and contact at a single point can be prevented. Therefore, even if the core piece 20 swings, it is difficult for a large stress to be applied to the outer pole 4 and the outer pole 4 is less likely to be chipped.

Here, as shown in FIG. 13, if only the curved portion 942 is formed on the outer pole 94 and the straight portion is not formed, both ends 949 of the curved portion 942 have acute angles. Therefore, when the core piece 920 swings, the core piece 920 swings around the acute-angled both ends 949. Therefore, there is a possibility that the two outer poles 94 facing each other come into contact with each other at a single point, and a large stress is applied to both ends 949, resulting in chipping.
On the other hand, in this example, as shown in FIG. 1, since the straight portion 41 is formed, it is possible to prevent the two outer poles 4 from contacting at one point even if the core piece 20 swings. It can suppress that 4 is missing.

In this example, as shown in FIGS. 2 and 3, two linear portions 41 are formed on the outer pole 4. The straight portions 41 are connected to both ends of the curved portion 42, respectively.
In this way, since the two linear portions 41 are formed, the stress applied to the outer pole 4 when the core piece 20 swings can be received by the two linear portions 41. Therefore, the stress applied to each linear part 41 can be made small, and it can suppress more effectively that the outer pole 4 is missing.

Further, as shown in FIG. 4, the base portion 5 of this example has a shape in which the length in the Y direction is gradually shortened from the outer pole 4 to the inner pole 3 in the X direction.
If it does in this way, since the gravity center of core piece 20 will exist in the position near outer pole 4, core piece 20 becomes difficult to rock. Therefore, it becomes easier to suppress the outer pole 4 from being missing.

  As described above, according to this example, it is possible to provide a transformer in which the core can be reduced in size and the outer pole is not easily chipped even when the core piece swings.

  In this example, the secondary coil 12 is the large diameter coil 13, but the primary coil 11 may be the large diameter coil 13. That is, when more current flows in the primary coil 11 than in the secondary coil 12, the primary coil 11 is constituted by a bus bar or the like, and the primary coil 11 is made larger in diameter than the secondary coil 12. You may comprise so that a current density may be made small.

( Reference Example 2)
In this example, the shape of the core piece 20 is changed. As shown in FIG. 8, the core piece 20 of this example has a maximum length in the Y direction shorter than a maximum length in the X direction.

If it does in this way, the core 2 can be made into an elongate shape and can be reduced in size. As a result, the overall shape of the transformer 1 can be elongated and the size can be reduced.
The transformer 1 is used as a component such as a DC-DC converter together with other electronic components. When the transformer 1 is elongated and downsized, when the other electronic component and the transformer 1 are arranged adjacent to each other, only the transformer 1 does not need to be extremely wider than the other electronic components. For this reason, a so-called dead space is hardly generated in the DC-DC converter, and the layout of components can be easily designed.

Others are the same as in Reference Example 1. Also, of the symbols used in the drawings relating to the present embodiment, the sign same as that used in Reference Example 1, unless otherwise indicated, represents the same constituent elements as in Reference Example 1.

(Example 1 )
In this example, the shape of the core piece 20 is changed. In this example, as shown in FIGS. 9 and 10, a chamfered portion 45 (C surface) is formed from the flat surface 410 to the contact surface 40. If it does in this way, angle (theta) (refer FIG. 10) which the chamfering part 45 and the contact surface 40 in the core piece 20 make can be made into an obtuse angle. That is, the angle θ of the portion to which stress is applied when the core piece 20 swings can be made an obtuse angle. Therefore, compared with the case where the angle θ is a right angle or an acute angle, a large stress is hardly applied, and the outer pole 4 can be further prevented from being chipped.

Others are the same as in Reference Example 1. Also, of the symbols used in the drawings relating to the present embodiment, the sign same as that used in Reference Example 1, unless otherwise indicated, represents the same constituent elements as in Reference Example 1.

  In this example, the chamfered portion 45 is a C surface, but may be a round surface as shown in FIG.

( Reference Example 3)
In this example, the shape of the second core 2b is changed. As shown in FIG. 12, the second core 2b of this example is not a combination of a plurality of core pieces 20, but is a single component. Further, the first core 2 a is composed of two core pieces 20 as in the first reference example.
If it does in this way, since the 2nd core 2b is made into one component, a number of parts can be reduced. Therefore, it is easy to reduce the manufacturing cost of the transformer 1.

Others are the same as in Reference Example 1. Also, of the symbols used in the drawings relating to the present embodiment, the sign same as that used in Reference Example 1, unless otherwise indicated, represents the same constituent elements as in Reference Example 1.

DESCRIPTION OF SYMBOLS 1 Transformer 11 Primary coil 12 Secondary coil 2 Core 2a 1st core 2b 2nd core 20 Core piece 3 Inner pole 4 Outer pole 40 Contact surface 41 Linear part 42 Curved part 43 Side 5 Base part G Gap

Claims (4)

A transformer (1) including a core (2) made of a soft magnetic material, a primary coil (11), and a secondary coil (12),
The core (2) comprises a first core (2a) and a second core (2b) arranged so as to sandwich the primary coil (11) and the secondary coil (12) from both sides in the axial direction,
The first core (2a) and the second core (2b) are arranged inside the primary coil (11) and the secondary coil (12) and face each other while providing a gap (G) therebetween. An inner pole (3), an outer pole (4) disposed outside the primary coil (11) and the secondary coil (12) and in contact with each other; the inner pole (3) and the outer pole (4) And a base part (5) for connecting the
The first core and (2a) is at least one of the second core (2 b), consists of two or more core pieces (20), each of said core pieces (20), said inner pole (3) And the outer pole (4) and the base portion (5),
The contact surface (40) with which the outer pole (4) abuts each other has the primary coil (11) and the secondary coil (on the side on the inner pole (3) side when viewed from the axial direction. 12), a curved portion (42) which is curved along the outer peripheral edge (130) of the large-diameter coil (13) which is a coil having a larger outer diameter, and a linear portion (41) which is formed linearly Have
In the normal direction, which is a direction parallel to the contact surface (40) and perpendicular to the straight portion (41), the straight portion (41) is any part of the curved portion (42). Than the inner pole (3) side or the position closest to the inner pole (3) of the curved portion (42) .
The outer pole (4) includes a curved surface (420) curved along the curved portion (42) as a side surface (490) on the inner pole (3) side, and a flat surface continuous to the curved surface (420). (410), and a chamfered portion (45) made of a C surface or a rounded surface is formed between the flat surface (410) and the contact surface (40), and the chamfered portion (45). The transformer (1) is characterized in that the linear portion (41) is formed at the boundary between the contact surface (40) and the contact surface (40 ).   The transformer (1) according to claim 1, wherein the outer pole (4) has two straight portions (41), and the straight portions (41) are connected to both ends of the curved portion (42), respectively. A transformer (1) characterized in that   The transformer (1) according to claim 1 or 2, wherein the base portion (5) is arranged so that the linear portion (41) increases from the outer pole (4) toward the inner pole (3) in the normal direction. The transformer (1) is characterized in that the length in the width direction, which is a direction parallel to the horizontal direction, is gradually shortened.   The transformer (1) according to claim 3, wherein the core piece (20) has a maximum length in the width direction shorter than a maximum length in the normal direction.

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