Coil mounting structure

Abstract

To provide a mounting structure of a coil capable of improving vibration resistance while securing mountability as a whole device.SOLUTION: A coil mounting structure 1 includes a core 15,17 around which a primary winding 16 and a secondary winding 18 are wound and which can share magnetic flux, and a housing 2 to which the primary winding 16, the secondary winding 18, and the core 15,17 are fixed. The core 15,17 includes the first core 15 around which the primary winding 16 is wound and which is fixed to the housing 2, and the second core 17 around which the secondary winding 18 is wound and one end of which is fixed to the housing, the inner diameter of the one core 15 is formed to be larger than the outer diameter of the other core 17, and the primary winding 16, the secondary winding 18, the first core 15, and the second core 17 are fixed in a state in which the other core 17 enters the inside of the one core 15.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a structure for mounting a coil having a winding and a core. [Background technology]

[0002] Patent Document 1 discloses an inductor including a core, a coil having a connection terminal, and a molded portion covering at least a portion of the core and the coil. The inductor of Patent Document 1 includes a core set having a first core and a second core, and a wound coil disposed inside the core set. The wound coil has lead-out portions and connection terminals at both ends, which are extended to the outside through an opening in the core set. In the inductor of Patent Document 1, the core set is covered with a molded portion formed by molding. Mounting portions are provided on both sides of the molded portion, and the lead-out portions and connection terminals are embedded therein. A hole is formed through the connection terminal portion in the thickness direction, and a processed portion with a thread or the like is formed inside the mounting portion, penetrating the hole so as to communicate with the hole. The entire device is firmly fixed by fastening screws into the hole and the processed portion. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-218532 Summary of the Invention [Problem to be solved by the invention]

[0004] In the inductor of Patent Document 1, the mounting portion is integrally formed with the molded portion, which gives the device a strong structure overall and improves vibration resistance. However, in the inductor of Patent Document 1, the molded portion and mounting portion are provided to cover the entire core set, lead-out portion, etc., which may result in an increase in the overall size of the device. Furthermore, to secure the lead-out portion and connection terminal portion, holes are formed in the connection terminal portion, and processed portions are formed in the mounting portion so as to align with the positions of the holes. This increases the volume occupied by the device as a whole, which may reduce the flexibility of installation of the device.

[0005] This invention has been made with a focus on the above-mentioned technical problems, and aims to provide a coil mounting structure that can improve vibration resistance while ensuring mountability of the entire device. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, the present invention provides a coil mounting structure comprising a primary winding on the input side, a secondary winding on the output side, a core around which the primary winding and the secondary winding are wound and which allows the primary winding and the secondary winding to share magnetic flux, and a housing for fixing the primary winding, the secondary winding, and the core, wherein the core comprises a first core around which the primary winding is wound and one longitudinal end of which is fixed to the housing, and a second core formed separately from the first core and around which the secondary winding is wound and one longitudinal end of which is fixed to the housing, wherein the inner diameter of one of the cylindrical cores, of the first core around which the primary winding is wound and the second core around which the secondary winding is wound, is larger than the outer diameter of the other cylindrical core, and the other core is fixed to the housing while inserted inside the one core. [Effects of the Invention]

[0007] In the coil mounting structure according to an embodiment of the present invention, the first coil, which has a primary winding wound around a first core, and the second coil, which has a secondary winding wound around a second core, are configured as separate bodies. Therefore, the mass of each of the first coil and the second coil is smaller than the mass of an integrated coil in which two windings are wound around a single core. That is, the weight (load) generated in the portion of the housing that holds the first coil or the second coil is smaller than the weight generated in the portion of the housing that holds the integrated coil. Alternatively, the inertial force generated in the first coil and the second coil due to vehicle vibrations or the like can be reduced. Furthermore, compared to the integrated coil, the centers of gravity of the first coil and the second coil can be shifted closer to the housing. That is, the distance from the fixed portion to the housing to the center of gravity of the first coil and the second coil can be shorter than that of the integrated coil. Therefore, for example, when vehicle vibrations or the like occur, stress generated at the base of each core and at the joints of each lead wire with the circuit board can be reduced. Therefore, when vibration or shock occurs to the vehicle, it is possible to suppress a decrease in the durability of each coil and each board. In addition, one core is embedded inside the other core, preventing the distance between the coils from increasing. This prevents a decrease in the effective value of the induced electromotive force generated on the output side, and therefore prevents or suppresses a decrease in the performance of the device. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a cross-sectional view illustrating a first embodiment of a coil mounting structure according to the present invention. [Figure 2] FIG. 2 is a cross-sectional view for explaining a second embodiment of the coil mounting structure according to the present invention. [Figure 3]Figure 3 is a diagram for explaining another example of a coil mounting structure in an embodiment of the present invention, where Figure 3(a) is a cross-sectional view for explaining a third embodiment of the coil mounting structure, and Figure 3(b) is a cross-sectional view for explaining a fourth embodiment of the coil mounting structure. DETAILED DESCRIPTION OF THE INVENTION

[0009] Next, the present invention will be described based on the embodiments shown in the drawings. Note that the embodiments described below are merely examples of specific embodiments of the present invention, and are not intended to limit the present invention.

[0010] The coil mounting structure 1 in the embodiment of the present invention is applied when mounting a common coil (common mode choke) or a transformer (voltage transformer) used for converting power on a vehicle. In other words, the coil mounting structure 1 is used when the common coil or transformer is attached to an engine room or a battery pack of a vehicle via a metal or resin case. The coil mounting structure 1 in the first embodiment of the present invention is mainly composed of a housing (case) 2, a first substrate 3, a second substrate 4, and an inductance section 5.

[0011] The housing 2 is used in an electronic control device mounted on a vehicle and holds multiple electronic components such as circuit boards inside. The housing 2 is made of a metal material such as aluminum or copper, or a resin material such as plastic or epoxy resin. The housing 2 is capable of efficient heat dissipation and is configured to be able to secure the boards, coils, and other components arranged inside. By securing the internal electronic components, a decrease in the durability of the electronic components due to vehicle vibrations and impacts is suppressed. The housing 2 is sealed (not shown) to improve its waterproof and dustproof performance. The housing 2 configured in this manner is fastened to the vehicle via a bracket or the like.

[0012] As shown in FIG. 1 , the housing 2 has a first support portion 6 and a second support portion 7 that extend so that their short sides face each other. The first support portion 6 and the second support portion 7 extend facing each other like beams, and each has two first fastening portions 8 and two second fastening portions 9 that protrude toward the opposing surfaces. The first substrate 3 is fastened to the first fastening surface, and the second substrate 4 is fastened to the second fastening surface, so that the first substrate 3 and the second substrate 4 are arranged facing each other. The housing 2 has a fixing portion 10 for integrating the first support portion 6 and the second support portion 7, which are molded separately, and is configured so that the first support portion 6 and the second support portion 7 can be integrated at the fixing portion 10 by a fixing member (not shown).

[0013] As shown in FIG. 1, the first substrate 3 and the second substrate 4 are fixed to the inside of the housing 2 by a first fastening member 11 and a second fastening member 12, respectively. Inside the housing 2, the first substrate 3 and the second substrate 4 are arranged facing each other. The first substrate 3 and the second substrate 4 are so-called printed circuit boards (PCBs) or printed wiring boards in which the wiring of the body is arranged on an insulating layer plate. The first substrate 3 and the second substrate 4 electrically connect and mechanically support electronic components. As such electronic components, a first coil and a second coil of the inductance unit 5, which will be described later, are bonded to the first substrate 3 and the second substrate 4, respectively. The printed circuit boards are also provided with pads and through holes (neither of which is shown) to which the windings of the inductance unit 5, which will be described later, are bonded.

[0014] The inductance unit 5, also called a coil, is an electronic component that converts electrical energy using a magnetic field, such as that of a common mode choke or transformer as described above. The inductance unit 5 is used in DC-DC converters, filter circuits, charging systems, and the like in vehicles. In the inductance unit 5, a magnetic field is generated by current flowing from a power source such as a battery. In the inductance unit 5, a self-induced electromotive force caused by changes in the generated magnetic field generates an electromotive force (induced electromotive force) in a direction that opposes changes in the current, thereby suppressing changes (pulsations) in the current and supplying a stable current. The inductance unit 5 includes a first coil 13 and a second coil 14.

[0015] The first coil 13 and the second coil 14 are each formed by a winding and a core. That is, as shown in Fig. 1, the first coil 13 is formed by winding a primary winding 16 in a spiral shape around a primary core 15. The second coil 14 is formed by winding a secondary winding 18 around a secondary core 17. The first coil 13 and the second coil 14 are arranged such that their longitudinal directions are aligned with the left-right direction or the vertical direction of the vehicle.

[0016] The primary winding 16 and the secondary winding 18 of the first coil 13 and the second coil 14 are identical in configuration and comprise insulatingly coated metal wire. The primary winding 16 and the secondary winding 18 are formed of a conductor (not shown) through which current flows during operation and an insulating coating (not shown) that covers the conductor with an insulating material. The primary winding 16 and the secondary winding 18 include, for example, enameled wire insulated by coating a copper wire with enamel paint. Note that the primary winding 16 and the secondary winding 18 are not limited to the enameled wire described above. They may also be formed of metal wire made of copper, aluminum, or the like as the conductor and an insulating coating made of mica, varnish, or the like. Increasing the number of turns, cross-sectional area, length, etc. of the primary winding 16 and the secondary winding 18 can increase the inductance. The turns ratio between the primary winding 16 and the secondary winding 18 may be set depending on the application. When used in a common coil or transformer as described above, the number of turns of the secondary winding 18 may be set to be larger than the number of turns of the primary winding 16.

[0017] The primary core 15 and secondary core 17 of the first coil 13 and the second coil 14 are cores made of a magnetic material. As shown in FIG. 1 , the primary core 15 is formed in a cylindrical shape, and the secondary core 17 is formed in a cylindrical shape with an outer diameter smaller than the inner diameter of the primary core 15. By using a magnetic material such as a metallic magnetic material or ferrite for the primary core 15 and the secondary core 17, the inductance of the inductance unit 5 can be increased. Furthermore, the magnitude of the inductance can be adjusted depending on the magnetic permeability of the magnetic material used for the primary core 15 and the secondary core 17.

[0018] The first coil 13 and the second coil 14 configured as described above are connected to the first substrate 3 and the second substrate 4, respectively. Specifically, the first bracket 19 integrated with the primary core 15 of the first coil 13 is joined to the first substrate 3. The first bracket 19 is integrated with the end of the primary core 15 opposite the second substrate 4 side. The first bracket 19 is fixed to the first substrate 3 via an adhesive or the like. Furthermore, the first lead wire 20 of the primary winding 16 is inserted into the above-mentioned through hole of the first substrate 3 and soldered thereto. In this way, the first coil 13 is fixed to the first substrate 3.

[0019] The second coil 14 is also fixed to the second substrate 4 in the same manner as the first coil 13. That is, a second bracket 21 integrated with the secondary core 17 of the second coil 14 is joined to the second substrate 4. The second bracket 21 is integrated with the end of the secondary core 17 opposite the first substrate 3. The second bracket 21 is fixed to the second substrate 4 via an adhesive or the like. In addition, the second lead wire 22 of the secondary winding 18 is inserted into the above-mentioned through hole of the second substrate 4 and soldered thereto. In this way, the second coil 14 is fixed to the second substrate 4.

[0020] The second coil 14 is disposed radially outward of the first coil 13. That is, the inner diameter of the second coil 14 is larger than the outer diameter of the first coil 13. Furthermore, since the first substrate 3 and the second substrate 4 are disposed opposite each other as described above, the first coil 13 is disposed inside the second coil 14, as shown in FIG. 1. As a result, the first coil 13 and the second coil 14 are disposed concentrically, as shown in FIG. 1. The first coil 13 and the second coil 14 are attached to the housing 2 or the substrates 3 and 4 so as not to come into contact with each other.

[0021] In the inductance unit 5 configured as described above, a current is passed through the first coil 13 by a power source such as a battery. That is, the first coil 13 is on the input side, and generates a magnetic field and generates magnetic flux when a current is passed from the power source to the primary winding 16. The magnetic flux is transmitted to the second coil 14 side.

[0022] In the second coil 14, an electromotive force (induced electromotive force) is generated due to a change in the magnetic flux on the first coil 13 side. That is, the voltage induced in the second coil 14 changes in response to a change in the current flowing through the first coil 13. As a result, a current flows through the secondary winding 18 in the second coil 14. That is, the second coil 14 is on the output side and supplies a current corresponding to the self-induced electromotive force to a load such as a connected device. The electromotive force at that time is determined based on the inductance in the inductance unit 5 and the rate of change of the flowing current. Therefore, in the inductance unit 5, the number of turns of the windings 16, 18 in each of the coils 13, 14, the cross-sectional area of ​​each of the coils 13, 14, the length of each of the coils 13, 14, the material (substance) used for each of the cores 15, 17, and the like are set according to the desired electromotive force.

[0023] In the coil mounting structure 1 configured as described above, the first coil 13 and the second coil 14 in the inductance section 5 are integrated, and then the first support section 6 and the second support section 7 are connected and integrated to complete the assembly. For example, the first coil 13 and the second coil 14 are formed by winding the primary winding 16 around the primary core 15 and the secondary winding 18 around the secondary core 17. The first coil 13 and the second coil 14 are then soldered to the first substrate 3 and the second substrate 4, respectively. Then, the first substrate 3 to which the first coil 13 is joined is fastened to the first support section 6, and the second substrate 4 to which the second coil 14 is joined is fastened to the second support section 7. That is, first fastening members 11 are fastened to the respective first fastening portions 8 of the first support portion 6 to fasten the first substrate 3, and second fastening members 12 are fastened to the respective second fastening portions 9 of the second support portion 7 to fasten the second substrate 4. Thereafter, the first support portion 6 and the second support portion 7 are integrated by the fixing portion 10, thereby completing the attachment of the inductance portion 5 to the housing 2.

[0024] As described above, in the coil mounting structure 1 according to the embodiment of the present invention, the first coil 13 and the second coil 14 are configured as separate bodies. Therefore, the mass of each of the first coil 13 and the second coil 14 can be smaller than the mass of an integrated coil in which two windings are wound around one core and the coil is joined to one substrate. That is, the weight (load) generated in the portion of the housing 2 that holds the integrated coil is smaller than the weight generated in the portion that fixes the first coil 13 on the first substrate 3 or the portion that fixes the second coil 14 on the second substrate 4. Furthermore, the centers of gravity of the first coil 13 and the second coil 14 can be shifted to positions closer to the substrates 3 and 4, respectively, compared to the centers of gravity of the integrated coil. That is, the center of gravity of the first coil 13 is closer to the first substrate 3, and the center of gravity of the second coil 14 is closer to the second substrate 4, compared to the centers of gravity of the integrated coil.

[0025] In this way, the weight (load) generated in the portion of the first substrate 3 supporting the first coil 13 and the portion of the second substrate 4 supporting the second coil 14 can be relatively small, thereby reducing the inertial force generated in the first coil 13 and the second coil 14 due to vehicle vibrations and the like. Furthermore, compared to an integrated coil, the distance between the center of gravity of the first coil 13 and the second coil 14 and the substrates 3 and 4 can be reduced. That is, the distance from the root portion of each coil 13 and 14, for example, the root portion of each core 15 and 17 and the joints of the lead wires 20 and 22 of the windings 16 and 18, to the center of gravity can also be reduced. Therefore, bending stress generated in the root portion of each core 15 and 17 and the joints of the lead wires 20 and 22 when the vehicle is vibrated can be reduced. This can prevent a decrease in the durability of the coils 13 and 14 and the substrates 3 and 4 when the vehicle is subjected to vibrations or impacts.

[0026] Moreover, since the first coil 13 and the second coil 14 are configured as separate bodies, high insulation can be ensured. Furthermore, the cores 15, 17 of the first coil 13 and the second coil 14 can be made of different materials. Furthermore, since the second coil 14 is disposed inside the first coil 13, the distance between the coils 13, 14 is prevented from increasing. In other words, a decrease in the effective value of the induced electromotive force generated in the second coil 14 can be prevented, and therefore a decrease in the performance of the inductance unit 5 can be prevented or suppressed.

[0027] Next, a second embodiment of the present invention will be described. In a coil mounting structure 31 according to the second embodiment of the present invention, a first substrate 3 and a second substrate 4 in a housing 2 are integrated by a spacer 32. In Fig. 2, only parts necessary for explanation are denoted by reference numerals, and the same components as those in Fig. 1 are denoted by the same reference numerals, and explanations thereof will be omitted or simplified.

[0028] As shown in FIG. 2 , the housing 2 in the second embodiment is disposed adjacent to the first substrate 3 and the second substrate 4 in the longitudinal direction. The housing 2 extends in a direction perpendicular to the longitudinal direction of the first substrate 3 and the second substrate 4. The housing 2 is formed with a first holding portion 33 and a second holding portion 34 configured to be able to sandwich the first substrate 3 and the second substrate 4, respectively. The first holding portion 33 and the first substrate 3 are integrated together by fastening a third fastening member 35 with the first substrate 3 sandwiched between the first holding portion 33. The second holding portion 34 and the second substrate 4 are integrated together by fastening a fourth fastening member 36 with the second substrate 4 sandwiched between the second holding portion 34.

[0029] 2, in the coil mounting structure 31 of the second embodiment, fifth fastening members 37 are provided which are fastened to both sides of the first coil 13 of the first substrate 3 and which penetrate the first substrate 3 in the plate thickness direction. Also, sixth fastening members 38 are provided which are fastened to both sides of the second coil 14 of the second substrate 4 and which penetrate the second substrate 4 in the plate thickness direction. Also, a spacer 32 is provided which integrates the opposing fifth fastening member 37 and sixth fastening member 38.

[0030] The spacer 32 is made of a material such as metal or plastic. At both ends of the spacer 32 in the axial direction, a screw groove (not shown) is formed inside the spacer 32 along the axial direction. The screw groove formed at both ends of the spacer 32 allows the fifth fastening member 37 or the sixth fastening member 38 described above to be screwed into the screw groove. This allows the spacer 32 to be fixed to the first substrate 3 and the second substrate 4.

[0031] An example of integrating the housing 2 and the substrates 3, 4 by attaching the spacer 32 configured in this manner will be described. First, through holes for inserting the fastening members 37, 38 are formed in each of the first substrate 3 with the first coil 13 integrated therein and the second substrate 4 with the second coil 14 integrated therein. The two spacers 32 are positioned from the surface of the first substrate 3 on which the first coil 13 is integrated, aligning the positions of the through holes, and then the fifth fastening member 37 is fastened. The fifth fastening member 37 is inserted through the first substrate 3 and screwed into a thread groove formed inside the spacer 32 along the axial direction, thereby fastening the fifth fastening member 37 and the two spacers 32 to the first substrate 3.

[0032] Next, the through hole of the second substrate 4 is aligned with the spacer 32 fixed to the second substrate 4 by the fifth fastening member 37, and positioned. In this state, the sixth fastening member 38 is inserted through the second substrate 4 and screwed into a thread groove formed inside the spacer 32 along the axial direction, thereby fastening the sixth fastening member 38 and the spacer 32 to the second substrate 4. As a result, the first substrate 3 and the second substrate 4 are integrated via the spacer 32.

[0033] The first substrate 3 and the second substrate 4 integrated in this manner are fastened to the housing 2. As described above, the housing 2 is formed with the first holding portion 33 and the second holding portion 34 to which the third fastening member 35 and the fourth fastening member 36 can be fastened while sandwiching the first substrate 3 and the second substrate 4, respectively. Therefore, the first substrate 3 is sandwiched between the first holding portion 33, and the third fastening member 35 is fastened while the insertion hole of the first substrate 3 is aligned with the screw hole of the first holding portion 33, and the fourth fastening member 36 is fastened while the second substrate 4 is sandwiched between the second holding portion 34. This allows the first substrate 3 and the second substrate 4 to be fixed to the housing 2.

[0034] With this configuration, the first substrate 3 and the second substrate 4 are integrated, which increases the degree of freedom in the positions at which the substrates 3, 4 are fastened to the housing 2 and reduces the number of fastening points. That is, compared to the case in which the first substrate 3 and the second substrate 4 are fastened to the housing 2 while being separate, as in the coil mounting structure 1 of the first embodiment shown in FIG. 1, the mountability of the inductance section 5 and the substrates 3, 4 can be improved.

[0035] Due to such improved mountability, it may be configured so that only one of the first board 3 and the second board 4 is fastened to the housing 2. Such an example will be described based on a third embodiment shown in Fig. 3(a) and a fourth embodiment shown in Fig. 3(b).

[0036] 3(a), in a coil mounting structure 41 according to the third embodiment, only the first substrate 3 is fastened to the housing 2. Specifically, both ends of the first substrate 3 in the longitudinal direction are formed longer than the second substrate 4, and seventh fastening members 42 are fastened to each of the extended portions. The housing 2 is disposed on the side of the first substrate 3 facing the second substrate 4, and the seventh fastening members 42 are fastened to the side of the first substrate 3 opposite the second substrate 4. This allows the inductance unit 5 and the substrates 3 and 4 to be fixed to the housing 2.

[0037] 3(b), in the coil mounting structure 51 of the fourth embodiment, only the second substrate 4 is fastened to the housing 2. Specifically, both ends of the second substrate 4 in the longitudinal direction are formed longer than the first substrate 3, and eighth fastening members 52 are fastened to each of the extended portions. The housing 2 is disposed on the side of the second substrate 4 facing the first substrate 3, and the eighth fastening members 52 are fastened to the side of the second substrate 4 opposite to the first substrate 3. This allows the inductance unit 5 and the substrates 3 and 4 to be fixed to the housing 2.

[0038] In the coil mounting structures 41, 51 configured as shown in the third and fourth embodiments, only one of the first substrate 3 and the second substrate 4 is fixed to the housing 2. Therefore, in addition to the above-mentioned effects, the substrates 3, 4 can be fixed according to the shape of the housing 2, etc., and the mountability can be further improved.

[0039] Although the embodiments of the present invention have been described above, the present invention is not limited to the above examples and may be modified as appropriate within the scope of achieving the object of the present invention. For example, the housings 2 may be configured as separate bodies. In this case, the first substrate 3 may be fixed to one housing 2 and the second substrate 4 may be fixed to the other housing 2. In other words, as long as the first coil 13 and the second coil 14 are configured as separate bodies, the housing 2 and the substrates 3 and 4 may be formed as either an integrated body or separate bodies. [Explanation of symbols]

[0040] 1,31,41,51 Mounting structure 2. Case 3 First board 4 Second board 5 Inductance section 6 First support part 7 Second support part 8 1st fastening part 9 Second fastening part 10 Fixed part 11 First fastening member 12 Second fastening member 13 First coil 14 Second coil 15 Primary core 16 Primary Winding 17 Secondary core 18 Secondary Winding 19 First Bracket 20 First lead wire 21 Second Bracket 22 Second lead wire 32 spacer 33 1st holding part 34 Second holding part 35 Third fastening member 36 Fourth fastening member 37 Fifth fastening member 38 Sixth fastening member 42 Seventh fastening member 52 Eighth fastening member

Claims

[Claim 1] The primary winding on the input side, A secondary winding on the output side; a core around which the primary winding and the secondary winding are wound, allowing the primary winding and the secondary winding to share magnetic flux; a housing for fixing the primary winding, the secondary winding, and the core, The core is a first core around which the primary winding is wound and one end in the longitudinal direction of which is fixed to the housing; a second core that is formed separately from the first core, has the secondary winding wound thereon, and has one end in the longitudinal direction fixed to the housing, the first core around which the primary winding is wound and the second core around which the secondary winding is wound, the inner diameter of one of the cylindrical cores being larger than the outer diameter of the other cylindrical core, The other core is fixed to the housing while being inserted inside the one core. A coil mounting structure characterized by:

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