JP2010272771A - Reactor - Google Patents

Abstract

A reactor capable of easily positioning a current sensor when the current sensor is attached to the reactor itself.
A reactor R1 performs positioning of the coil 1 with respect to the core 2, the core 2 having a coil 1, an intermediate core in which the coil 1 is disposed, and an end core 2s exposed without being disposed. A bobbin 3 and a resin part 4 that covers the periphery of the combination of the core 2 and the coil 1 are provided. A current sensor 5 for detecting a current flowing through the coil 1 is attached to the reactor R1. The attachment position of the current sensor 5 to the reactor R1 is the winding end 1B, and the resin part 4 is formed with a positioning part 4p for positioning the current sensor 5 at a position corresponding to the attachment position of the current sensor 5.
[Selection] Figure 1

Description

  The present invention relates to a reactor used for a component of a DC-DC converter for an electric vehicle such as a hybrid vehicle. In particular, the present invention relates to a reactor capable of easily positioning the current sensor when the current sensor is attached to the reactor itself.

  An electric vehicle such as a hybrid vehicle is equipped with a DC-DC converter that raises and lowers a DC voltage, and a reactor is one of the parts of this converter. Conventionally, a typical reactor has a structure in which an assembly in which a coil is arranged on an annular core is housed in a case, and the case is filled with resin and sealed (for example, Patent Document 1). reference).

  The reactor described in Patent Document 1 includes a track-shaped core having a straight portion, a coil disposed in the core, an intermediate case that houses an assembly of the core and the coil, and an intermediate case that houses the combination. And a housing case. In this reactor, the straight portion of the core where the coil is disposed is covered with the inner bobbin, and the coil is wound around the outer side of the inner bobbin. The reactor has outer bobbins attached to both ends of the coil, and both ends of the coil are sandwiched between the outer bobbins. Furthermore, since this reactor dissipates the heat generated in the reactor by energizing the coil, the case is used with the case installed on the heat sink.

  By the way, for example, in the case of a configuration in which DC-DC converters for driving a vehicle are combined in parallel in multiple phases, the current of each phase is detected for phase stop control according to load fluctuations and protection against current concentration in a specific phase. Is desired. For example, Patent Document 2 proposes to attach a current sensor to a bus bar that is electrically connected to the coil via a terminal in order to measure the current of the reactor (coil).

JP 2008-28290 A JP 2006-217759 A (FIGS. 1 to 3)

  Recently, power converters including converters have been required to have higher density and smaller size. Depending on how the bus bar is handled and how the peripheral parts of the bus bar are arranged, it is not always possible to attach a current sensor to the bus bar. It is not always possible.

  However, even if it is assumed that the current sensor is attached to the reactor itself, the conventional technology has a specific configuration for how to attach the current sensor to the coil winding formed by bending the winding in a complicated manner. Not proposed. In addition, when the current sensor is attached to the winding, the current sensor cannot be accurately positioned.

  The present invention has been made in view of the above circumstances, and one of its purposes is to provide a reactor capable of easily positioning a current sensor when the current sensor is attached to the reactor itself. is there.

  The reactor of this invention is provided with the coil formed by winding a coil | winding, the core in which a coil is arrange | positioned, and the resin part which covers at least one part of the outer periphery of a coil. The resin part is characterized in that a positioning part for positioning a current sensor for detecting a current flowing in the coil is formed.

  According to this configuration, since the positioning portion is formed in the resin portion, the current sensor can be easily positioned when the current sensor is attached to the winding of the coil. By the way, although the current sensor is attached to the winding of the coil, the attachment position is not particularly limited, and the positioning portion is provided at a position corresponding to the attachment position of the current sensor. The positioning portion can be formed, for example, in a concave shape or a convex shape, and is preferably provided on the upper surface of the resin portion so that it can be placed and positioned after the current sensor is attached.

  In the present invention, the positioning portion may be formed at a position corresponding to the current sensor attached to the winding end.

  In a coil, there is usually a small gap between winding turns, and it may be difficult to attach a current sensor to the windings forming the turns. On the other hand, the winding end is connected to a terminal when assembled into a final product such as a converter, and a bus bar is connected to the terminal, so that a predetermined space is secured between peripheral parts. Therefore, it is preferable that the current sensor is attached to the winding end and the positioning portion is formed so as to correspond thereto. More preferably, it is preferable to attach a current sensor to a linear portion between the winding end connected to the terminal and the turn forming portion (coil spiral portion) of the winding.

  In the present invention, the resin portion includes an inner resin portion that retains the shape of the coil and an outer resin portion that is disposed outside the inner resin portion, and the positioning portion is formed on at least one of the outer resin portion and the inner resin portion. May be.

  A coil that is simply wound with a winding acts as a springback, and a relatively large space is formed between the winding turns. Since the shape of such a coil is not maintained, it is difficult to handle such as expansion and contraction of the coil, and the assembly workability is deteriorated. In order to reduce the size of the reactor, it is desirable to compress the coil so that the space between the winding turns is as small as possible. Thus, for example, Patent Document 1 proposes a method of holding the coil in a compressed state by sandwiching both ends of the coil with outer bobbins and storing the coil in an inner case. However, with this method, the number of parts and the assembly process are large, and the assembly workability is poor.

  On the other hand, according to the above configuration in which the resin portion is divided into the inner resin portion and the outer resin portion, and the shape of the coil is held by the inner resin portion, the handling of the coil becomes easy and the assembly workability of the reactor is excellent. . Specifically, a coil molded body in which the coil is integrally formed with the inner resin portion is used. In addition, the coil molded body can also function as a conventional reactor bobbin (inner bobbin, outer bobbin and middle case), so the number of parts and the assembly process can be reduced. Improvement in assembly workability can be expected.

  In the above configuration, when the positioning portion is provided in the inner resin portion, the outer resin portion is disposed so that at least the positioning portion of the inner resin portion is not covered with the outer resin portion, and the positioning portion is exposed from the outer resin portion. Further, a positioning portion may be provided in each of the inner resin portion and the outer resin portion, and these positioning portions may be combined to form one positioning portion.

  In the reactor according to the present invention, since the positioning portion is formed in the resin portion, the current sensor can be easily positioned when the current sensor is attached to the reactor itself.

(A) is a schematic perspective view of the reactor according to Embodiment 1, and (B) is a partially enlarged cross-sectional view of a positioning portion in the AA cross section of FIG. (A). It is a schematic exploded view for demonstrating the components which comprise the reactor which concerns on Embodiment 1. FIG. It is a schematic perspective view of the reactor which concerns on Embodiment 2. FIG. 5 is a schematic perspective view of a coil molded body used for a reactor according to Embodiment 2. FIG. It is a schematic perspective view of another coil molded object.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Moreover, the same code | symbol is attached | subjected to the same member in the figure.

(Embodiment 1)
A reactor R1 according to the first embodiment will be described with reference to FIGS. The reactor R1 includes a coil 1, a core 2 having an intermediate core 2m where the coil 1 is disposed, and an end core 2s which is exposed without being disposed, and a bobbin 3 which positions the coil 1 with respect to the core 2. And a resin portion 4 that covers the periphery of the combination of the core 2 and the coil 1. The bobbin 3 includes a cylindrical bobbin 3m that covers the outer periphery of the intermediate core 2m, and a frame-shaped bobbin 3s that contacts the end surface of the coil 1. Further, the resin part 4 is formed with a positioning part 4p for positioning a current sensor 5 for detecting a current flowing through the coil 1. Hereinafter, each configuration will be described in more detail.

  The coil 1 is obtained by winding a rectangular winding edgewise, and an outer peripheral surface is formed by a turn of the winding. As shown in FIG. 2, the coil 1 is composed of a pair of coil elements 1a and 1b whose axial directions are parallel to each other, and both the coil elements 1a and 1b are formed by a single winding. Specifically, the winding is bent in a U shape at the other end in the axial direction of the coil 1 so that the end portions (starting end 1A and terminal end 1B) of the winding are located at one end in the axial direction of the coil 1. By providing the portion 1U, both coil elements 1a and 1b are formed by a single winding.

  As shown in FIG. 2, the core 2 connects the end cores 2s to the end faces of both intermediate cores 2m so that the ends of the pair of intermediate cores 2m on which the coil elements 1a and 1b are arranged are connected to each other. By doing so, it is configured in an annular shape. The intermediate core 2m is a rectangular parallelepiped core component configured by sequentially arranging four core pieces 20 and three gap members g. On the other hand, the end core 2s has a surface to which the end surface of the intermediate core 2m is connected (hereinafter, this surface is referred to as a “core connection surface”), and the width increases toward the surface opposite to this surface. It is a core component having a substantially trapezoidal cross section. Here, the lower end of the end core 2s is protruded downward with respect to the lower surface of the intermediate core 2m so that the lower surface of the end core 2s is substantially at the same position as the lower surface of the coil element 1a (1b).

  The core piece 20 and the end core 2s are made of a magnetic material. For example, a laminated body in which silicon steel plates are laminated, or a soft magnetic powder such as iron powder is coated with an insulating coating, and the powder is obtained by pressure molding the powder. It can be comprised with a molded object. The gap material g is made of a nonmagnetic material, and can be formed of a ceramic plate material such as glass epoxy resin or alumina, for example.

  As shown in FIG. 2, the bobbin 3 includes a cylindrical bobbin 3m and a frame bobbin 3s. An intermediate core 2m is held on the inner periphery of the cylindrical bobbin 3m, and a coil element 1a (1b) is mounted on the outer periphery of the cylindrical bobbin 3m. On the other hand, the frame-shaped bobbin 3s has a substantially rectangular plate shape and has two openings 3o through which the end of the intermediate core 2m passes.

  The cylindrical bobbin 3m and the frame bobbin 3s are made of an insulating material and can be made of a resin such as polyphenylene sulfide (PPS), liquid crystal polymer (LCP), polytetrafluoroethylene (PTFE), or the like.

  The resin portion 4 is made of, for example, a resin such as an epoxy resin, a urethane resin, an unsaturated polyester resin, or PPS, and has a function of protecting the core 2 and the coil 1 from the external environment and mechanical stress. The resin portion 4 is formed with a positioning portion 4p for positioning the current sensor 5 at a position corresponding to the mounting position of the current sensor 5 (see FIG. 1A). Here, the mounting position of the current sensor 5 is the end 1B of the winding, and the positioning portion 4p is formed on the upper surface of the resin portion 4 in a concave rectangular frame surrounding the winding (see FIG. 1 (B)). .

  As the current sensor 5, a commercially available one can be used, and it is usually an annular shape having a central hole through which the current wire to be measured (winding) passes. Specific examples of current sensor 5 include Hall element type and current transformer type current sensors, search coils, Rogowski coils, optical fibers, MR (magnetoresistive) elements, GMR (giant magnetoresistive effect) elements, MI Examples include a current sensor using a (magnetic impedance) element. Further, a clamp-type current sensor configured to be openable and closable may be used, and in this case, it can be detachably attached from the outside of the winding. Here, an example in which a commercially available Hall element type current sensor is used is shown.

  A specific example of the method of assembling the reactor R1 will be described with reference to FIG. First, a pair of intermediate cores 2m in which the core piece 20 and the gap material g are joined together by an adhesive are prepared, and a cylindrical bobbin 3m is attached to the outer periphery of each of the intermediate cores 2m.

  Next, the coil element 1a (1b) is mounted on the outer periphery of the intermediate core 2m covered with the cylindrical bobbin 3m, and the frame-shaped bobbin 3s is attached to both end faces of the coil element 1a (1b). At this time, the end of the intermediate core 2m penetrates through the opening 3o of the frame bobbin 3s.

  Next, end cores 2s are arranged on the end surfaces of both intermediate cores 2m so as to connect the end portions of both intermediate cores 2m, and the end surfaces of the intermediate cores 2m and the core connecting surfaces of the end cores 2s are bonded with an adhesive. By joining, the core 2 is formed in an annular shape. In such a combination of the core 2 and the coil 1, a closed magnetic circuit is formed in the core 2 by passing a current through the coil 1 (energization).

  Next, the combination of the core 2 and the coil 1 is housed in a mold. Then, after filling the resin from the opening side of the mold and curing the resin to form the resin part 4, the resin part 4 as illustrated in FIG. 1 is provided with a positioning part 4 p by removing it from the mold. Reactor R1 is completed. Here, for example, a convex portion corresponding to the positioning portion 4p is formed at a predetermined position in the mold, and the positioning portion 4p is formed simultaneously with the formation of the covering portion 4.

  When attaching the current sensor 5 to the reactor R1, as shown in FIG. 1, the center hole of the current sensor 5 is inserted into the end 1B of the winding exposed from the resin part 4, and the current sensor 5 is mounted on the positioning part 4p. Position. Further, after positioning the current sensor 5 at the positioning portion 4p, the current sensor 5 may be securely fixed to the positioning portion 4p with, for example, an adhesive or an adhesive tape.

  The positioning portion 4p may be formed so that the entire current sensor 5 is buried, or may be formed so that a part of the current sensor 5 is exposed (see FIG. 1B). Further, the positioning part 4p may be formed, for example, by cutting the resin part 4 after the resin part 4 is formed.

(Embodiment 2)
A reactor R2 according to the second embodiment will be described with reference to FIGS. The reactor R2 is described in the first embodiment in that the resin part 4 includes the inner resin part 41 and the outer resin part 42, and the coil 1 uses the coil molded body 10 formed integrally with the inner resin part 41. Different from reactor R1. Hereinafter, the difference will be mainly described.

  The coil molded body 10 is obtained by integrally molding the coil 1 on the inner resin portion 41, and an insertion hole 10o through which the intermediate core 2m is inserted is formed at a position corresponding to the inner circumference of each coil element 1a, 1b. . The inner resin portion 41 has a function of holding the shape of the coil 1. Specifically, the shape of the coil 1 is maintained by filling the resin between the winding turns of the coil 1 and forming the resin continuously from one end side to the other end side of the coil 1. . Therefore, handling of the coil 1 is facilitated by using the coil molded body 10.

  Further, when the inner resin portion 41 is formed in a state where the coil 1 is compressed, the coil 1 is held in a compressed state, so that the reactor can be downsized. In particular, the reactor can be further miniaturized by compressing the coil so that no gap is formed between substantially adjacent winding turns. Here, the starting end 1A and the terminal end 1B of the winding, the upper surfaces of the coil elements 1a and 1b, and a part of the side surface where the coil elements do not face each other are exposed from the inner resin portion 41. On the other hand, since the inner peripheral surfaces and end surfaces of the coil elements 1a and 1b are covered with the inner resin portion 41, the inner resin portion 41 can also function as the bobbin 3 described in the first embodiment. By using the molded body 10, the number of parts and the assembly process can be reduced.

  The coil molded body 10 can be manufactured by using, for example, the following molding die. The molding die is composed of a pair of first and second molds that can be opened and closed. The first mold includes an end plate positioned on one end side (start end / end end side) of the coil 1 and a rectangular parallelepiped core inserted into the inner periphery of each of the coil elements 1a and 1b. The second mold includes an end plate located on the other end side (bent portion side) of the coil 1 and a side wall covering the periphery of the coil. The first mold and the second mold include a plurality of rod-shaped bodies that can be advanced and retracted into the mold by a drive mechanism, and the end surfaces of the coil elements 1a and 1b are pressed by these rod-shaped bodies to thereby form the coil 1. It is configured so that it can be compressed. The rod-like body is preferably made as thin as possible in order to reduce the portion of the coil 1 that is not covered with the inner resin portion 41, and has sufficient strength and heat resistance to compress the coil 1.

  The coil 1 is housed in such a molding die. At this time, a predetermined gap is provided between the surface of the molding die and the coil 1. At this stage, the coil 1 is not yet compressed, and a gap is formed between the winding turns.

  Next, the molding die is closed, and the core of the first die is inserted into the inner periphery of each coil element 1a, 1b. At this time, the gap between the core and the coil element is made substantially uniform over the entire circumference. Subsequently, the rod-shaped body is advanced into the molding die to hold the coil 1 in a predetermined shape. At this time, the coil 1 may be compressed so that the windings adjacent to each other in the axial direction are in contact with each other so as to eliminate the gap between the winding turns as much as possible.

  Thereafter, the resin is filled into the molding die from the resin injection port, the resin is cured to form the inner resin portion 41, and then taken out from the molding die, so that the coil 1 as illustrated in FIG. The coil molded body 10 formed integrally with the portion 41 is completed. Note that the plurality of small holes formed in the portion pressed by the rod-shaped body may be filled with an appropriate insulating material or the like, or may be left as it is. In the coil molded body 10 illustrated in FIG. 4, a part of the outer peripheral surface of each coil element 1a, 1b is exposed from the inner resin portion 41, but a part of the inner peripheral surface of each coil element 1a, 1b is exposed. May be exposed from the inner resin portion 41, or the entire outer peripheral surface of each coil element 1a, 1b may be covered by the inner resin portion 41.

  In the above-described manufacturing method example of the coil molded body, the case where the coil is integrally formed with the inner resin portion has been described. However, for example, the coil and the intermediate core can be integrally formed with the inner resin portion.

  Even in this case, the above-described molding die can be used. Specifically, with the intermediate core inserted in the inner periphery of each coil element instead of the core, the molding die is filled with resin, and the resin is cured to form the inner resin portion.

  The outer resin portion 42 covers the periphery of the combination of the core 2 and the coil molded body 10, and has a function of protecting the core 2 and the coil molded body 10 from the external environment and mechanical stress. Further, the outer resin portion 42 has a concave positioning portion 4p formed on the upper surface of the outer resin portion 42 corresponding to the mounting position of the current sensor.

  Reactor R2 is assembled in substantially the same manner as reactor R1 in the first embodiment. Insert the intermediate core through the insertion hole 10o of the coil molded body 10, and then place the end cores 2s on the end faces of both intermediate cores so that the ends of both intermediate cores are connected to each other. To do.

  Next, the combination of the core 2 and the coil molded body 10 is housed in a mold. Then, after filling the resin from the opening side of the mold and curing the resin to form the outer resin part 42, the positioning part 4p is formed on the outer resin part 42 as illustrated in FIG. The provided reactor R2 is completed. Here, for example, a convex portion corresponding to the positioning portion 4p is formed at a predetermined position in the mold, and the positioning portion 4p is formed simultaneously with the formation of the outer covering portion.

  The inner resin portion 41 and the outer resin portion 42 are preferably made of a thermosetting resin such as a phenol resin, an unsaturated polyester resin, or an epoxy resin, and may be made of the same type or different types of resins.

  In the reactor R2 described above, the case where the positioning part 4p is formed in the outer resin part 42 has been described, but the positioning part 4p can also be formed in the inner resin part 41.

  The coil molded body 11 illustrated in FIG. 5 is different from the coil molded body 10 described in the second embodiment in that a positioning portion 4p is formed in the inner resin portion 41. The coil molded body 11 can also be manufactured by using the same configuration as the molding die used for manufacturing the coil molded body 10. Here, for example, a core corresponding to the positioning portion 4p is housed together with the coil 1 at a predetermined position in the molding die, so that the positioning portion 4p is formed simultaneously with the formation of the inner covering portion 41. The positioning portion 4p is formed by forming a convex peripheral wall 4w corresponding to the shape of the current sensor.

  When the positioning portion 4p is formed on the inner resin portion 41, the outer resin portion is formed so that at least the positioning portion 4p of the inner resin portion 41 is not covered by the outer resin portion when the outer resin portion is formed. Then, the positioning portion 4p is exposed from the outer resin portion. Further, when forming the outer resin portion, for example, a core is arranged in the positioning portion 4p of the inner resin portion 41, and the positioning portion is also formed in the outer resin portion so as to be continuous with the positioning portion of the inner resin portion. These positioning portions may be combined to form one positioning portion.

(Modification 1)
In the above-described embodiment, the example in which the current sensor is attached by inserting the center hole of the current sensor at the end of the winding, more specifically, at the end of the winding has been described. However, a clamp-type current sensor is used. May be. When using a clamp-type current sensor, it should be attached to a portion other than the end of the winding, for example, a bent portion 1U connecting both coil elements 1a and 1b in FIG. it can. However, when the coil element is attached at an intermediate position in the axial direction, a sufficient gap for attaching the current sensor to the winding is often not formed between the winding turns, and it is difficult to attach to the winding forming the turn. There are many cases. Therefore, one turn of the coil element is projected from the outer peripheral surface of the coil, and a current sensor is attached to a winding portion of the projected turn that protrudes in a direction orthogonal to the outer peripheral surface of the coil. It arrange | positions in a positioning part so that the surface orthogonal to a direction may oppose a coil outer peripheral surface. When the coil element is attached to the intermediate position in the axial direction, it is possible to reliably prevent the current sensor from protruding from the outline when the reactor is viewed in plan. For example, in one of the two coil elements 1a and 1b in FIG. 1, one turn at an axially intermediate position protrudes upward from the upper surface of the outer peripheral surface of the coil, and the coil elements at the protruding portions face each other. A current sensor may be attached to.

(Modification 2)
Further, a terminal block having a terminal connected to the end may be mounted on the end of the winding. Therefore, when the current sensor is attached to the end portion of the winding, the current sensor may be sandwiched between the resin portion and the terminal block. Thereby, it can prevent that a current sensor remove | deviates from a positioning part. Moreover, when the positioning part is formed so that a part of the current sensor is exposed from the resin part, the positioning part may be formed on the surface of the terminal block facing the current sensor.

(Modification 3)
In the above-described embodiment, the molded type reactor in which the case is omitted by molding the combined body of the core and the coil (coil molded body) with the resin portion (outer resin portion) has been described. Even if it is a potting type reactor in which the combined body is housed in a case and sealed with resin, the effects of the present invention can be achieved. In this case, the reactor is completed by filling the case with a potting resin and curing the resin to form a resin portion (outer resin portion).

  When using a reactor, insert holes for inserting fixing brackets (for example, bolts) are formed in the resin part (outer resin part) in the mold type or in the case in the potting type, and used for heat dissipation mechanisms such as heat sinks. Install securely.

  Note that the present invention is not limited to the above-described embodiment, and can be modified as appropriate without departing from the gist of the present invention. For example, the attachment position of the current sensor 5 in FIG. Moreover, although the positioning part 4p of FIG. 1 and 3 is formed in the concave shape, it can also be formed in the convex shape as illustrated in FIG. In the case of a convex positioning portion, it is preferable to form the current sensor so as to contact at least two side surfaces of the current sensor, particularly two side surfaces sandwiching the corners.

  The reactor of the present invention can be suitably used as a component such as a DC-DC converter for an electric vehicle such as a hybrid vehicle.

R1, R2 reactor
1 Coil 1a, 1b Coil element
1A Start (winding end) 1B End (winding end) 1U Bend
2 cores 2m intermediate core 2s end core
20 Core piece g Gap material
3 bobbin 3m cylindrical bobbin 3s frame bobbin
3o opening
4 Resin part 41 Inner resin part 42 Outer resin part
4p Positioning part 4w Perimeter wall
5 Current sensor
10,11 Coil molded body 10o insertion hole

Claims (3)

A reactor comprising a coil formed by winding a winding, a core on which the coil is disposed, and a resin portion that covers at least a part of the outer periphery of the coil,
The reactor is characterized in that a positioning portion for positioning a current sensor for detecting a current flowing through the coil is formed in the resin portion.   The reactor according to claim 1, wherein the positioning portion is formed at a position corresponding to a current sensor attached to the winding end. The resin portion includes an inner resin portion that retains the shape of the coil and an outer resin portion that is disposed outside the inner resin portion,
The reactor according to claim 1, wherein the positioning portion is formed in at least one of the outer resin portion and the inner resin portion.

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