Reactor

Abstract

The present invention provides a reactor, comprising: a reactor body (2) having a core material (3) including a pressed powder magnetic core, a resin component (4) covering the core material (3), and a coil (5) wound around the outer periphery of the resin component (4); a shell (7) having a bottom surface (71) and a side wall (72) and accommodating the reactor body (2); and a filling and forming portion (8) fixing the reactor body (2) to the shell (7). The resin component (4) comprises: a bottom opening portion (44), which is arranged on the end surface facing the bottom surface (71) of the shell (7) so that the core material (3) is exposed; and a back opening portion (46), which is arranged on the end surface perpendicular to the winding axis direction of the coil (5) and facing the side wall (72) so that the core material (3) is exposed. The back opening portion (46) has an exposed portion (461) that is not covered by the filling molding portion (8) and is exposed, so that bubbles generated from the core material can be released to the outside of the inductor, thereby improving the heat dissipation.

Description

Technical Field

[0001] The present invention relates to a reactor. Background Art

[0002] Reactors are used in various applications, such as drive systems of hybrid vehicles, electric vehicles, or fuel cell vehicles. For example, as a reactor used in a vehicle-mounted boost circuit, there is known a reactor that is formed by covering an annular core by molding with a resin mold, and a coil is wound around the outer circumference of the core.

[0003] This type of reactor is a reactor body housed in a case made of metal such as aluminum, a filler is injected between the reactor body and the case, and the filler is solidified, thereby filling the gap between the reactor body and the case with the filler, and the reactor body has a core material including a pressed powder core formed by pressing, and a coil wound on the core material. That is, the reactor body is covered with the filler. The reactor body generates heat due to the current flowing through the coil. The heat generated by the reactor body is transferred to the case via the filler, thereby dissipating the heat.

[0004] [Prior art literature]

[0005] [Patent Document]

[0006] Patent Document 1: Japanese Patent Application Publication No. 2012-209333 Summary of the invention

[0007] [Problems to be solved by the invention]

[0008] When injecting the filler, the filling material is injected in a vacuum to prevent bubbles from being mixed into the filler. By setting the vacuum state, the air mixed into the powder core expands during the compaction, and bubbles are generated from the powder core. If the bubbles remain inside the reactor, thermal resistance will be caused. In addition, since bubbles are mixed into the filler, the filler may not be evenly filled into the reactor body, which will hinder the heat dissipation of the reactor.

[0009] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a reactor capable of releasing bubbles generated from a core material to the outside of the reactor, thereby improving heat dissipation.

[0010] [Technical means to solve the problem]

[0011] The inductor of the present invention includes: an inductor body, having a core material including a pressed powder magnetic core, a resin component in which the core material is embedded, and a coil wound around the outer circumference of the resin component; a shell, having a bottom surface and a side wall standing upright from the bottom surface, and accommodating the inductor body; and a filling and forming portion, which is formed by solidifying a filling material and fixes the inductor body to the shell, and the resin component has: a bottom opening portion, which faces the bottom surface of the shell to expose the core material; and a back opening portion, which is orthogonal to the winding axis direction of the coil and faces the side wall to expose the core material, and the back opening portion has an exposed portion that is not covered by the filling and forming portion.

[0012] The area of ​​the exposed portion may be set to be 10% or more of the area of ​​the bottom surface opening.

[0013] The core material may have a step at an edge of an end surface exposed from the bottom surface opening, and the resin member may fill the step and be flush with the core material exposed from the bottom surface opening.

[0014] The press-formed core material may have a sliding surface formed by sliding a mold, and the sliding surface may be exposed from the back opening.

[0015] The core material may also be an annular core material having a pair of legs extending along the winding axis direction of the coil, the bottom opening having a first edge extending over a range including the pair of legs, and the resin component having a protrusion extending from the first edge of the bottom opening and in contact with the core material exposed from the bottom opening.

[0016] The resin member may further include straight portions covering the pair of leg portions, respectively, wherein the straight portion has a side opening on a side surface parallel to the side wall, the side opening being parallel to the winding axis direction of the coil and exposing the core material.

[0017] [Effects of the Invention]

[0018] According to the present invention, a reactor can be obtained in which bubbles generated from a core material can be released to the outside of the reactor, thereby improving heat dissipation. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is an overall perspective view of the reactor according to the first embodiment.

[0020] Figure 2 It is an exploded perspective view of the reactor according to the first embodiment.

[0021] Figure 3 This is a perspective view of the U-shaped core material according to the first embodiment.

[0022] Figure 4 yes Figure 1 AA cross-section diagram.

[0023] Figure 5 It is a bottom perspective view of the reactor body according to the first embodiment.

[0024] Figure 6 It is a side view showing a state where the filling molded portion covers the reactor body according to the first embodiment.

[0025] Figure 7 This is a schematic diagram showing the movement of bubbles inside the core material.

[0026] Figure 8 It is used to indicate the temperature measurement location of the embodiment. Figure 1 BB cross-section diagram.

[0027] Explanation of symbols

[0028] 1: Reactor

[0029] 2: Reactor body

[0030] 3: Core material

[0031] 31, 32: U-shaped core material

[0032] 33: I-shaped core material

[0033] 34: Spacer

[0034] 35: Step Difference

[0035] 4: Resin components

[0036] 41, 42: Resin body

[0037] 41a, 41b: Straight line

[0038] 41c: Connection part

[0039] 44: Bottom opening

[0040] 441: First Edge

[0041] 45: Protrusion

[0042] 46: Back opening

[0043] 461: Exposed

[0044] 47: Side opening

[0045] 5: Coil

[0046] 51a, 51b: Coil

[0047] 52a, 52b: Lead wire

[0048] 6: Temperature sensor

[0049] 7: Shell

[0050] 71: Bottom

[0051] 72: Sidewall

[0052] 8: Filling and forming section

[0053] 9: Terminal

[0054] X, X2, X3, X4: Bubble DETAILED DESCRIPTION

[0055] (First Embodiment)

[0056] Please refer to the attached Figure 1 The structure of the reactor according to the present embodiment will be described. Figure 1 It is a perspective view showing the overall structure of the reactor according to the first embodiment. Figure 2 This is an exploded perspective view of the reactor of the first embodiment. In addition, in this specification, the winding direction of the coil is the "Y-axis direction". The direction perpendicular to the Y-axis direction and parallel to the direction adjacent to the two coils 51a and 51b is called the "X-axis direction". The direction perpendicular to the X-axis direction and the Y-axis direction is called the "Z-axis direction", and the Z-axis direction is the height direction of the reactor. Figure 1 The direction indicated by the arrow in the Z-axis direction is set as the "up" side, and the opposite direction is set as the "down" side. "Down" is also called "bottom". These directions are used to express the positional relationship of each structure of the reactor, and do not limit the positional relationship and direction when the reactor is set on the setting object.

[0057] The reactor 1 is an electromagnetic component that converts electric energy into magnetic energy and stores and releases it, and is used for voltage step-up and step-down. The reactor 1 of this embodiment is a large-capacity reactor used in the drive system of a hybrid vehicle or an electric vehicle, for example. The reactor is a main component of the step-up circuit installed in these vehicles.

[0058] like Figure 1 and Figure 2 As shown, the reactor 1 of the present embodiment includes a reactor body 2, a housing 7, and a filling molded portion 8. The reactor body 2 includes a core material 3, a resin member 4, a coil 5, and a temperature sensor 6. The reactor body 2 is accommodated in the housing 7. By injecting a filling material into the housing 7, the reactor body 2 is fixed to the housing 7, and the filling molded portion 8 is formed.

[0059] The core material 3 is in an annular shape, and the annular shape has a pair of straight line portions extending in parallel along the winding axis direction of the coil 5, and a substantially U-shaped connecting portion connecting the pair of straight line portions. That is, the core material 3 has an annular shape of a substantially rounded rectangular shape, and the substantially rounded rectangular shape is a shape in which the convex sides of a pair of partial circles are separated in opposite directions and face each other, and the two ends of each partial circle are connected by parallel straight lines.

[0060] The straight part of the wound coil 5 is the leg part that generates magnetic flux. The connecting part of the unwound coil 5 is the yoke part that allows the magnetic flux generated by the leg part to pass through. By allowing the magnetic flux generated by the leg part to pass through the yoke part, a ring-shaped closed magnetic circuit is formed in the core material 3.

[0061] The core material 3 includes a plurality of I-shaped core materials 33 constituting the leg portion, two U-shaped core materials 31 constituting the yoke portion, a U-shaped core material 32, and a plurality of spacers 34. The spacers 34 are arranged between the I-shaped core materials 33 or between the U-shaped core materials 31, the U-shaped core materials 32, and the I-shaped core materials 33. The U-shaped core materials 31, the U-shaped core materials 32, and the I-shaped core materials 33 are bonded with adhesive via the spacers 34, thereby forming the core material 3 into an annular core material.

[0062] Figure 3 31 is a perspective view of the U-shaped core material 31 and the U-shaped core material 32. The U-shaped core material 31 and the U-shaped core material 32 include a pressed powder magnetic core. The U-shaped core material 31 and the U-shaped core material 32 are formed by filling a magnetic powder coated with an insulating film into a mold and pressing it. Figure 3 As shown, the U-shaped core materials 31 and 32 have sliding surfaces S, and the sliding surfaces S are formed by sliding between the pressing surfaces P formed by pressing the two end surfaces in the Z-axis direction and the mold. Figure 3 The arrows on the upper and lower sides indicate the pressing direction.

[0063] Figure 4 yes Figure 1 Specifically, Figure 4 Yes Figure 1 The dotted line AA shown in FIG. 1 is cut parallel to the height direction and the cross-sectional view is observed from the scroll axis direction (arrow direction). Figure 4 As shown, the surface exposed from the bottom opening 44 of the U-shaped core material 31 (hereinafter also referred to as the bottom surface of the core material 3) has a step 35 that is lowered by one level at the edge. The step 35 located at the edge is filled by the resin member 4, so that the bottom surface of the core material 3 becomes flush with the resin member 4. In addition, the bottom surface of the U-shaped core material 32 also has the same step 35 as the U-shaped core material 31.

[0064] The spacer 34 is a plate-shaped gap spacer. The spacer 34 can separate the core materials into a magnetic gap of a specified width to prevent the inductance of the reactor from decreasing. As the spacer 34, a non-magnetic body, ceramic, non-metal, resin, carbon fiber, or a composite material of two or more thereof or a spacer paper can be used. In addition, the spacer 34 does not necessarily need to be provided, and the U-shaped core material 31, the U-shaped core material 32, and the I-shaped core material 33 can also be directly connected by an adhesive, and an air gap can also be provided.

[0065] The core material 3 is embedded in the resin member 4 to insulate the core material 3 from the coil 5. Examples of the resin constituting the resin member 4 include epoxy resin, unsaturated polyester resin, urethane resin, bulk molding compound (BMC), polyphenylene sulfide (PPS), and polybutylene terephthalate (PBT).

[0066] Resin member 4 such as Figure 2 As shown in FIG. 1 , the resin member 4 is divided into two parts, and has a resin body 41 and a resin body 42. That is, the resin member 4 is formed by independently forming the resin body 41 and the resin body 42. The resin body 41 has a pair of straight portions 41a and a straight portion 41b, and a connecting portion 41c connecting the straight portions 41a and the straight portions 41b. The resin member 4 is formed by making the ends of the straight portions 41a and 41b of the resin body 41 and the resin body 42 face each other and join them.

[0067] The resin bodies 41 and 42 are formed by inserting the U-shaped core materials 31 and 32 by a casting molding method. In other words, the resin bodies 41 and 42 are the covering parts of the U-shaped core materials 31 and 32, and the outer peripheral part of the U-shaped core material 31 is in close contact with the inner peripheral part of the resin bodies 41 and 42. The end surfaces of the resin bodies 41 and 42 facing the bottom surface 71 of the housing 7 are as shown in FIG. Figure 4 As shown, the U-shaped core material 31 is flush with the resin body 41. That is, during the molding, the resin that becomes the resin body 41 fills the portion of the U-shaped core material 31 that becomes the step 35, and the resin body 41 and the bottom surface of the U-shaped core material 31 become the same plane. In addition, the resin body 42 is also flush with the bottom surface of the U-shaped core material 32 in the same manner as the resin body 41.

[0068] Figure 5 This is a three-dimensional view of the bottom surface of the reactor body. Figure 5As shown, the resin bodies 41 and 42 have a substantially trapezoidal bottom opening 44 at the end faces facing the bottom face 71 of the housing 7 . The bottom faces of the U-shaped core members 31 and 32 are exposed from the bottom opening 44 . Figure 5 The oblique lines represent the U-shaped core material 31 and the U-shaped core material 32. The end surfaces (bottom surfaces of the core materials) of the U-shaped core materials 31 and 32 exposed from the bottom surface opening 44 are the pressing surfaces P.

[0069] The bottom opening 44 has a first edge 441, which extends to at least a range between a pair of legs of the core material 3 extending in the winding direction. The first edge 441 is provided at a position perpendicular to the winding direction of the bottom opening 44 opening in a substantially trapezoidal shape and close to the coil 5. In other words, the first edge 441 is provided on a line connecting the ends of each pair of legs of the core material 3.

[0070] Furthermore, the resin bodies 41 and 42 have a protrusion 45. The protrusion 45 extends from the first edge and contacts the core material 3 exposed from the bottom surface opening 44. In the protrusion 45, the surface facing the core material 3 exposed from the bottom surface opening 44 contacts the core material 3 as a whole. The protrusion 45 is provided at a position in the center of the long side of the bottom side of the bottom surface opening 44 which opens in a roughly trapezoidal shape. That is, the protrusion 45 extends from between a pair of legs of the core material 3. The protrusion 45 has an elongated flat plate shape. The long side of the protrusion 45 is provided in a manner parallel to the X-axis direction.

[0071] The protrusion 45 prevents bubbles in the U-shaped core material 31, 32 from escaping from the bottom opening 44. That is, the protrusion 45 prevents bubbles from escaping from between a pair of legs extending in a straight line of the U-shaped core material 31, 32. Therefore, the protrusion 45 is in contact with the U-shaped core material 31, 32. The long side of the protrusion 45 has a length that is substantially the same as the length between the pair of legs extending in a straight line of the U-shaped core material 31, 32.

[0072] The protrusion 45 is formed integrally when the resin bodies 41 and 42 are molded. Alternatively, the protrusion 45 may be formed independently of the resin bodies 41 and 42, and after the resin bodies 41 and 42 in which the U-shaped core materials 31 and 32 are embedded by molding are formed, the protrusion 45 may be bonded to the resin bodies 41 and 42 by an adhesive or the like.

[0073] Resin body 42 Figure 2 , Figure 5As shown, two back openings 46 are provided at the end face which is orthogonal to the winding axis direction of the coil 5 and faces the side wall 72 of the housing 7. The back openings 46 expose the U-shaped core material 31 and the U-shaped core material 32. More specifically, the back openings 46 expose the sliding surfaces S of the U-shaped core material 31 and the U-shaped core material 32. The shape of the back openings 46 is roughly rectangular. In addition, the resin body 41 also has a back opening 46 similarly to the resin body 42.

[0074] Figure 6 This is a side view of the reactor body 2 covered by the filling molded portion 8 as viewed from the winding direction (the housing 7 is not shown). Figure 6 As shown, the back opening portion 46 has an exposed portion 461 that is not covered by the filling and forming portion 8. In other words, the back opening portion 46 has a portion covered by the filling and forming portion 8 and a portion not covered. The exposed portion 461 exposes the sliding surface S of the U-shaped core material 31 and the U-shaped core material 32. That is, the U-shaped core material 31 and the U-shaped core material 32 have a portion that is not covered by the resin member 4 and the filling and forming portion 8 and is exposed.

[0075] The exposed portion 461 serves as an escape path for bubbles generated from the core material 3 when the filler is injected. The area of ​​the exposed portion 461 is preferably 10% or more of the area of ​​the bottom surface opening 46. If the area of ​​the exposed portion 461 is 10% or more of the area of ​​the bottom surface opening 46, bubbles can be well released to the outside of the reactor.

[0076] The straight portions 41a and 41b of the resin body 41 have side openings 47. The side openings 47 are provided on the end surfaces of the straight portions 41a and 41b parallel to the side wall 72 of the housing 7 and parallel to the Y-axis direction. The side openings 47 expose the core material 3.

[0077] The coil 5 includes a conductive member insulated and coated with enamel, etc. In the present embodiment, the coil 5 is an edgewise coil including a rectangular copper wire. However, the wire material or winding method of the coil 5 is not limited thereto, and may be in other forms.

[0078] The coil 5 has a pair of left and right coils 51a and 51b, and the pair of coils 51a and 51b are arranged in a manner that the winding axis directions become parallel. The ends of the coils 51a and 51b are connected by a connecting wire 41c, and the connecting wire 41c is made of the same raw material as the coils 51a and 51b. The coils 51a and 51b respectively have lead wires 52a and 52b, which are connected to the terminal 9 by welding or the like, and are electrically connected to the external device.

[0079] The temperature sensor 6 detects the temperature of the reactor 1. As the temperature sensor 6, for example, a thermistor whose resistance changes with temperature can be used, but the invention is not limited thereto. The temperature sensor 6 can be electrically connected to a device provided outside the reactor 1 to transmit temperature information of the reactor 1 to the external device.

[0080] The housing 7 accommodates the reactor body 2. The housing 7 has a box-like shape with an open upper surface. That is, the housing has a substantially rectangular bottom surface 71, and side walls 72a, 72b, 72c, and 72d that stand upright in the height direction from the edges of the four sides of the bottom surface 71, and the upper surface is open. The reactor body 2 is inserted into the accommodation space of the housing 7 from the opening. The accommodation space is a space surrounded by the bottom surface 71 and the side walls 72a, 72b, 72c, and 72d.

[0081] The housing space of the housing 7 is slightly larger than the reactor body 2. In other words, the side walls 72a, 72b, 72c, and 72d of the housing 7 are larger than the reactor body 2 to cover the periphery of the reactor body 2. Therefore, gaps are formed between the side walls 72a, 72b, 72c, and 72d of the housing 7 and the reactor body 2. The height of the housing 7 in the Z-axis direction, that is, the height of the side wall 72 is lower than the height of the reactor body 2 in the Z-axis direction. In addition, the height of the side wall 72 can be the same as the height of the reactor body 2 or higher than the height of the reactor body 2.

[0082] The filling molding part 8 is a member formed by filling a filling material in the gap between the reactor body 2 and the housing 7 and curing it. That is, the filling molding part 8 is formed in the gap between the reactor body 2 and the housing 7. The filling molding part 8 fixes the reactor body 2 to the housing 7. As a filling material, in order to ensure the heat dissipation performance of the reactor 1 and reduce the vibration propagation from the reactor body 2 to the housing 7, a relatively soft and highly thermally conductive resin is suitable. Specifically, silicone resin, urethane resin, epoxy resin, acrylic resin, etc. can be listed.

[0083] The filling molded portion 8 does not entirely cover the rear opening portion 46 . In other words, the rear opening portion 46 has an exposed portion 461 exposed from the filling molded portion 8 .

[0084] (Assembly work)

[0085] The assembly operation of the reactor 1 of the present embodiment will be described. As described above, the resin member 41 in which the U-shaped core material 31 is embedded, and the resin member 42 in which the U-shaped core material 32 and the terminal 9 are embedded are formed by molding with the resin. The I-shaped core material 33 and the spacer 34 are inserted into the straight portion 41a and the straight portion 41b of the resin member 41, and the U-shaped core material 31, the U-shaped core material 32, the I-shaped core material 33 and the spacer 34 are bonded by an adhesive or the like.

[0086] The coils 51a and 51b are mounted outside the straight portions 41a and 41b, and the ends of the resin members 41 and 42 divided into two parts are made to face each other and joined, thereby forming the reactor body 2. Subsequently, the reactor body 2 is accommodated in the housing 7. After accommodation, a filler is injected from the injection port 73. The injected filler is cured to form the filling molded portion 8, and the reactor 1 is obtained.

[0087] (effect)

[0088] When the core material 3 including the powder magnetic core is pressed and formed, air is mixed into the core material 3. On the other hand, when the filler is injected, it must be done in a vacuum to prevent bubbles from being mixed into the filler. At this time, the air contained in the core material 3 expands and generates bubbles by setting the vacuum. In order to ensure heat dissipation, the generated bubbles must be released to the outside of the reactor 1.

[0089] Figure 7 It is a schematic diagram showing the movement of bubbles X inside the core material. In the present embodiment, the resin body 41 and the resin body 42 have a bottom opening portion 44 and a back opening portion 46. The bubbles X can escape from the opening portion 44 and the opening portion 46 to the outside of the reactor 1. In particular, the back opening portion 46 has an exposed portion 461 that is not covered by the resin member 4 and the filling molding portion 8. The opening portions 44 and the opening portions 46 other than the exposed portion 461 are covered by the filling material that constitutes the filling molding portion 8. Since the filling material is viscous, it is difficult for the bubbles X to escape from the air. Moreover, if bubbles X are mixed into the filling material, it is also possible that the filling material cannot be uniformly filled into the reactor body 2. In the present embodiment, since there is an exposed portion 461 that is not covered by the filling material, it is easy for the bubbles X to be released from the exposed portion 461 to the outside of the reactor 1. Since the bubbles will move in a direction that is easy to be released to the outside, as shown in FIG. Figure 7 As shown in FIG. 4 , the number of bubbles X toward the exposed portion 461 increases. Therefore, more bubbles X can be released from the exposed portion 461 to the outside of the reactor.

[0090] What is exposed from the back opening 46 and the exposed portion 461 is the sliding surface S of the U-shaped core material 31, 32. On the other hand, what is exposed from the bottom opening 44 is the pressing surface P of the U-shaped core material 31, 32. During press forming, the air contained inside the U-shaped core material 31, 32 gathers on the sliding surface S. Specifically, due to the pressing, a large pressure is applied to the pressing surface P of the core material 3, so the air contained inside the U-shaped core material 31, 32 moves in a direction away from the pressing surface P. Moreover, the air moving in the direction of leaving wants to be released to the outside of the U-shaped core material 31, 32 and moves in the direction of the sliding surface S. In this way, the air that cannot be released to the outside during the press forming of the U-shaped core material 31, 32 gathers near the sliding surface S.

[0091] Furthermore, since a greater pressure is applied to the pressing surface P than to the sliding surface S, the pressing surface P is formed densely with fewer gaps than the sliding surface S. On the other hand, since the sliding surface S makes the mold slide, it has unevenness on the surface compared with the pressing surface P, and the bubbles X located inside the core material 3 are easily released to the outside. That is, with respect to the bubbles X, the sliding surface S makes it easier to release the bubbles X than the pressing surface P. Therefore, more bubbles X can be released to the outside of the reactor from the back opening portion 46 that exposes the sliding surface S of the core material 3, especially from the exposed portion 461 of the back opening portion 46.

[0092] In this embodiment, the edge of the U-shaped core material 31 and the U-shaped core material 32, which is exposed from the bottom opening 44, has a step 35, and the resin member 4 covers the U-shaped core material 31 and the U-shaped core material 32 in a manner of filling the step 35. The bubbles X are easily released from the edge of the core material 3. Therefore, by covering the step 35 of the bottom surface of the U-shaped core material 31 and the U-shaped core material 32 with the resin member 4, the resin member 4 acts as a shield to block the release path of the bubbles X2.

[0093] Specifically, if Figure 7 As shown, the resin member 4 filling the step 35 prevents the bubbles X2 from being released from the bottom surface opening 44, and directs the bubbles X2 toward the exposed portion 461. In other words, by reducing the number of bubbles X2 released from the bottom surface opening 44, the number of bubbles X directed toward the exposed portion 461 is increased. Therefore, the number of bubbles X that can be released from the exposed portion 461 to the outside of the reactor 1 can be increased.

[0094] In particular, if the area of ​​the exposed portion 461 is set to be 10% or more of the area of ​​the bottom surface opening 44, the bubbles X released from the exposed portion 461 will appear significantly. It is presumed that this is because by setting the area of ​​the exposed portion 461 to be 10% or more of the area of ​​the bottom surface opening 44, the area of ​​the exposed portion 461 increases, and the amount of bubbles X that can be released from the exposed portion 461 also increases, so the amount of bubbles X toward the exposed portion 461 increases.

[0095] Furthermore, since the bottom opening 44 is provided, there are also bubbles X3 directed toward the bottom opening 44, and in particular, the bubbles X3 are likely to escape from between a pair of legs extending in the winding direction of the core material 3 exposed from the bottom opening 44. However, since the bottom opening 44 is covered with a filling material, it is more difficult to release the bubbles X3 to the outside of the reactor 1 than to the exposed portion 461, and therefore it is desirable to direct the bubbles X3 toward the exposed portion 461 as much as possible.

[0096] In this embodiment, the resin member 4 has a protrusion 45 and is provided between the legs of the core material 3. Figure 7 As shown, the protrusion 45 prevents the bubbles X3 from being released to the outside from between the pair of legs of the core material 3. As a result, it is difficult for the bubbles X3 to escape to the outside from the bottom surface opening 44. The bubbles X3 that are not released to the outside from the bottom surface opening 44 can be directed toward the sliding surface S that is easy to release to the outside. In addition, the bubbles X3 toward the sliding surface S are released to the outside from the exposed portion 461. Therefore, by having the protrusion 45 on the resin member 4, more bubbles X can be released to the outside.

[0097] The edges of the U-shaped core materials 31 and 32 exposed from the bottom opening 44 have a step 35, and the resin member 4 covers the step and is flush with the U-shaped core materials 31 and 32. Thus, more bubbles X4 can be released to the outside from the bottom opening 44.

[0098] In the past, the edge of the bottom surface of the core material exposed from the bottom opening had no step difference, and the resin member covered the edge of the bottom surface of the core material. That is, the core material and the resin member were not formed flush, and the resin member was convex in shape corresponding to the edge covering the bottom surface of the core material. In this previous shape, for bubbles released from the bottom surface of the core material, the bubbles would accumulate between the resin member covering the edge of the bottom surface of the core material and the core material. Therefore, the release of bubbles toward the outside of the reactor would be blocked by the resin member covering the edge of the bottom surface of the core material.

[0099] On the other hand, in the present embodiment, the bottom surface of the U-shaped core material 31, 32 is flush with the resin member 4. That is, the end surface of the U-shaped core material 31, 32 exposed from the bottom surface opening 44 is not covered by the resin member 4. The bubbles X4 released from the bottom surface of the U-shaped core material 31, 32 will not be blocked by the resin member 4. Therefore, it is possible to suppress the bubbles X4 from accumulating between the U-shaped core material 31, 32 and the resin member, so that more bubbles X can be released from the bottom surface opening 44.

[0100] Furthermore, the straight portions 41a and 41b of the resin body 41 have side openings 47. Bubbles X generated from the I-shaped core material 33 inserted into the straight portions 41a and 41b are not accumulated inside the straight portions 41a and 41b, but can be released from the side openings 47 to the outside of the reactor 1.

[0101] (Effect)

[0102] The reactor 1 of this embodiment includes: a reactor body 2, having a core material 3 including a pressed powder magnetic core, a resin component 4 covering the core material 3, and a coil 5 wound on the outer periphery of the resin component 4; a shell 7, having a bottom surface 71 and a side wall 72 erected from the bottom surface 71, accommodating the reactor body 2; and a filling and forming portion 8, which is formed by solidifying a filling material and fixes the reactor body 2 to the shell 7, and the resin component 4 has: a bottom opening portion 44, which is provided on the end surface facing the bottom surface 71 of the shell 7, so that the core material 3 is exposed; and a back opening portion 46, which is provided on the end surface orthogonal to the winding axis direction of the coil 5 and facing the side wall 72, so that the core material 3 is exposed, and the back opening portion 46 has an exposed portion 461 that is not covered by the filling and forming portion 8 and is exposed.

[0103] Thus, the bubbles X generated from the core material 3 can be released from the exposed portion 461 not covered by the resin member 4 and the filling molded portion 8 to the outside of the reactor 1, thereby reducing the thermal resistance. Furthermore, by releasing the bubbles X from the exposed portion 461 not covered by the filling material, it is possible to suppress the bubbles X from being mixed into the filling material, so that the filling material can be spread over the fine parts of the reactor body 2 and filled without omission. Therefore, the heat dissipation of the reactor 1 can be improved.

[0104] The area of ​​the exposed portion 461 is 10% or more of the area of ​​the bottom opening 44. That is, the area of ​​the exposed portion 461 not covered by the resin member 4 and the filling molded portion 8 is large. As a result, more bubbles X can be released from the exposed portion 461, so that the thermal resistance can be further reduced, and the reactor 1 with good heat dissipation can be obtained.

[0105] The core material 3 has a step 35 at the edge of the core material 3 exposed from the bottom surface opening 44, and the resin member 4 fills the step 35 and is flush with the core material 3 exposed from the bottom surface opening 44. In this way, the resin member 4 that fills the step of the core material 3 can suppress the bubbles X from heading toward the bottom surface opening 44 and can make them head toward the exposed portion 461, so that more bubbles X can be released to the outside of the reactor 1. In addition, by making the core material 3 exposed from the bottom surface opening 44 and the resin member 4 flush, there are no bubbles X whose paths are blocked by the resin member 4, and it is possible to suppress the bubbles X from accumulating between the resin member 4 and the core material 3, and the bubbles X can also be efficiently released from the bottom surface opening 44. Therefore, the heat dissipation of the reactor 1 can be improved.

[0106] Furthermore, the resin member 4 has a bottom opening 44 and a back opening 46, and the filling molded portion 8 formed by solidifying the filling material covers the space between the core material 3 and the housing 7 exposed from the bottom opening 44 and the back opening 46. Thus, the heat of the reactor body 2 can be efficiently transferred from the bottom opening 44 and the back opening 46 to the housing via the filling material, thereby further improving the heat dissipation of the reactor 1.

[0107] The pressed core material 3 has a sliding surface S for sliding the mold, and the sliding surface S is exposed from the back opening 46. The sliding surface S makes it easier for bubbles X to be released to the outside of the reactor 1 than the pressing surface P, so more bubbles X can be released from the exposed portion 461. Therefore, the bubbles X remaining in the reactor 1 can be suppressed, and the heat dissipation of the reactor 1 can be improved.

[0108] The core material 3 is an annular core material having a pair of legs extending in the winding axis direction of the coil 5, the bottom surface opening 44 has a first edge 441 extending over a range including the pair of legs, and the resin member 4 has a protrusion 45 extending from the first edge 441 of the bottom surface opening 44 and contacting the core material 3 exposed from the bottom surface opening 44. Thus, the bubbles X can be directed toward the exposed portion 461 rather than the bottom surface opening 44, so that more bubbles X can be released to the outside of the reactor 1, and the heat dissipation of the reactor 1 can be improved.

[0109] The resin member 4 further includes straight portions 41a and 41b covering a pair of legs, respectively, and the straight portions 41a and 41b have side openings 47 for exposing the core material 3 on the side parallel to the winding axis direction of the coil 5 and parallel to the side wall 72. Thus, the bubbles X generated from the I-shaped core material 33 can be released to the outside of the reactor 1, thereby improving the heat dissipation of the reactor 1.

[0110] The filler covers the space between the core material 3 and the case 7 exposed from the side opening 47. Thus, the heat of the reactor body 2 can be efficiently transferred to the case 7 via the filler, and thus the heat dissipation of the reactor 1 can be improved.

[0111] (Example)

[0112] The embodiments of the present invention are described with reference to Table 1 and compared with the comparative examples. The reactor 1 of the embodiment has the same structure as the reactor described in the first embodiment. That is, the resin member 4 has a bottom opening 44, a back opening 46, and a protrusion 45, and the back opening 46 has an exposed portion 461 that is not covered by the filling molding portion 8. On the other hand, in the reactor of the comparative example, the resin member has a bottom opening, a back opening, and the back opening has an exposed portion. That is, the difference between the embodiment and the comparative example is whether the resin member has a protrusion.

[0113] The initial temperature and the temperature after the reliability test of the reactor of the embodiment and the comparative example were measured. The temperature was measured under the conditions of core material loss 94W, coil loss 200W, and water cooling temperature 60°C. Moreover, the temperature after the reliability test was the temperature measured under the above conditions after being placed in an environment with an ambient temperature of 170°C for 100 hours. The results are shown in Table 1.

[0114] [Table 1]

[0115]

[0116] As shown in Table 1, the embodiment and comparative example measured the temperature at three locations: between coils, on the upper surface of the coil, and on the upper surface of the I-shaped core material. Figure 8 As shown in A, it refers to the temperature between two coils arranged in parallel with the winding axis direction, which is the temperature of the center part of the coil in the Y-axis direction and the Z-axis direction. Figure 8 As shown in B, it refers to the temperature of the central part of the upper surface of one coil in the X-axis direction and the Y-axis direction. Figure 8 C indicates the temperature of the upper surface of the I-shaped core material arranged at the inner periphery of the coil, that is, the temperature of the central portion of the I-shaped core material in the X-axis direction between the coil and the I-shaped core material.

[0117] As shown in Table 1, first, the initial temperature of the embodiment is lower than the initial temperature of the comparative example at all measurement locations. Moreover, the difference between the initial temperature after the reliability test and the temperature after the reliability test at all measurement locations of the embodiment is as low as about 5°C compared to the comparative example. That is, the temperature of the embodiment does not rise after the reliability test compared to the comparative example.

[0118] It can be said that this is the result of providing the protrusion 45 in the embodiment, thereby releasing more bubbles X from the exposed portion 461 to the outside of the reactor 1. Specifically, the comparative example does not have a protrusion, so bubbles are generated between the bottom surface of the core material and the shell, and the filler cannot be filled evenly. Moreover, in the comparative example, due to being placed at a high temperature of 170°C in the ambient temperature for a long time, the bubbles generated between the core material and the shell expand, and the filler filled between the core material and the shell peels off. As a result, the comparative example cannot efficiently transfer the heat generated by the reactor body to the shell via the filler, resulting in a large temperature rise.

[0119] On the other hand, the embodiment having the protrusion 45 can suppress the generation of bubbles X between the bottom surface of the core material 3 and the housing 7 by releasing more bubbles from the exposed portion 461 to the outside of the reactor 1. In other words, the embodiment can suppress the mixing of bubbles X into the filler, so that the filler can be uniformly filled into the reactor body 2. Therefore, even if the reliability test is performed, the bubbles X will not expand and the filler will not peel off, so good heat dissipation can be maintained. Therefore, it can be said that the embodiment that improves the heat dissipation of the reactor 1 has achieved a low initial temperature of all the measurement parts compared to the comparative example, and further, the temperature rise after the reliability test is also low.

[0120] (Other embodiments)

[0121] In this specification, the embodiments of the present invention are described, but the embodiments are presented as examples and are not intended to limit the scope of the invention. The embodiments described above can be implemented in various other forms, and various omissions, substitutions, and changes can be made without departing from the scope of the invention. The embodiments and their variations are included in the scope or gist of the invention.

[0122] In this embodiment, the resin bodies 41 and 42 have a rear opening 46 that opens in a substantially rectangular shape, but the shape of the rear opening 46 is not limited thereto, and the rear opening 46 may be circular as long as the area of ​​the exposed portion 461 is 10% or more of the area of ​​the bottom opening 44. Also, as for the number of rear openings 46, as long as the total area of ​​the exposed portions is 10% or more of the area of ​​the bottom opening 44, the resin bodies 41 and 42 may have one rear opening 46 that opens widely, or may have two or more rear openings 46.

Claims

1. A reactor, characterized in that: include: The reactor body comprises a core material including a powder magnetic core, a resin member in which the core material is embedded, and a coil wound around the outer periphery of the resin member; a housing having a bottom surface and side walls erected from the bottom surface and accommodating the reactor body; and The filling forming part is formed by curing the filling material, and fixes the reactor body to the housing. The resin member has: A bottom opening portion is provided at a position facing the bottom surface of the housing and where the coil is not wound, so that the core material is exposed; as well as The back opening is provided at a position perpendicular to the winding axis direction of the coil and facing the side wall, so that the core material is exposed. The back opening has an exposed portion which is not covered by the filling and molding portion and is exposed. The area of ​​the exposed portion is at least 10% of the area of ​​the bottom opening. The core material formed by pressing has a sliding surface formed by sliding of the die, The sliding surface is exposed from the rear opening.

2. The reactor according to claim 1, characterized in that: The core material has a step at the edge of the surface exposed from the bottom opening. The resin member fills the step difference and is flush with the core material exposed from the bottom surface opening.

3. The reactor according to claim 1 or 2, characterized in that: The core material is an annular core material having a pair of legs extending along the winding axis direction of the coil. The bottom opening has a first edge extending over a range including between the pair of legs. The resin member has a protrusion that protrudes from the first edge of the bottom surface opening and contacts the core material exposed from the bottom surface opening.

4. The reactor according to claim 3, characterized in that: The resin member further includes straight portions respectively covering the pair of leg portions, The linear portion has a side opening portion on a side surface parallel to the side wall, the side opening portion being parallel to the winding axis direction of the coil and exposing the core material.

5. A reactor, characterized in that: include: The reactor body comprises a core material including a powder magnetic core, a resin member in which the core material is embedded, and a coil wound around the outer periphery of the resin member; a housing having a bottom surface and side walls erected from the bottom surface and accommodating the reactor body; and The filling forming part is formed by curing the filling material, and fixes the reactor body to the housing. The resin member has: A bottom opening portion is provided at a position facing the bottom surface of the housing and where the coil is not wound, so that the core material is exposed; as well as The back opening is provided at a position perpendicular to the winding axis direction of the coil and facing the side wall, so that the core material is exposed. The back opening has an exposed portion which is not covered by the filling and molding portion and is exposed. The core material has a step at the edge of the surface exposed from the bottom opening. The resin member fills the step difference and is flush with the core material exposed from the bottom surface opening.

6. A reactor, characterized in that: include: The reactor body comprises a core material including a powder magnetic core, a resin member in which the core material is embedded, and a coil wound around the outer periphery of the resin member; a housing having a bottom surface and side walls erected from the bottom surface and accommodating the reactor body; and The filling forming part is formed by curing the filling material, and fixes the reactor body to the housing. The resin member has: A bottom opening portion is provided at a position facing the bottom surface of the housing and where the coil is not wound, so that the core material is exposed; as well as The back opening is provided at a position perpendicular to the winding axis direction of the coil and facing the side wall, so that the core material is exposed. The back opening has an exposed portion which is not covered by the filling and molding portion and is exposed. The core material is an annular core material having a pair of legs extending along the winding axis direction of the coil. The bottom opening has a first edge extending over a range including between the pair of legs. The resin member has a protrusion that protrudes from the first edge of the bottom surface opening and contacts the core material exposed from the bottom surface opening.

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