JP2017120822A - Output noise reduction device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an output noise reduction device capable of improving filter characteristics while achieving miniaturization of a device, and of improving assemblability.SOLUTION: A fixed part 41 and the like of a lead frame 25 are mounted with a chip capacitor and molded by a first mold part 51, and connects between a bus bar 21 and ground terminal parts 43 and 44. Four U-shaped cores 81 surrounding the bus bar 21 are inserted into insertion holes 71 and 72, and arranged so as to sandwich the first mold part 51 in the fore and back direction. A filter module configures a π-shaped filter circuit by the chip capacitor and the U-shaped cores 81. In this configuration, by dividing a core into the plurality of U-shaped cores 81, and connecting the chip capacitor according to the divided U-shaped cores 81, filter characteristics can be improved while maintaining the same total value of inductance and capacitance as before division.SELECTED DRAWING: Figure 4

Description

  The technology disclosed in the present application relates to an output noise reduction device that reduces noise mixed in an output voltage flowing through a bus bar inserted in a magnetic core.

  The output voltage and output signal output from the switching power supply and other electronic devices may be mixed with noise at the operating frequency of the electronic device or the like and its harmonic frequency. Such noise may adversely affect external electronic devices, and is required to be reduced as necessary. For example, noise generated from a switching power supply mounted on an automobile may become so-called radio noise that is superimposed on an audio signal or the like and adversely affects viewing. On the other hand, for example, in order to remove noise flowing through a bus bar provided as an output path of an output signal, there is a noise filter device configured by inserting a bus bar into a magnetic core (for example, Patent Document 1). .

JP 2005-93536 A

  Further, as a method of configuring a higher performance noise filter using the above-described noise filter device, for example, it is conceivable to configure a plurality of filter circuits by attaching a plurality of magnetic core units to a bus bar. However, in this case, there is a risk of increasing the size of the apparatus by attaching a plurality of magnetic core units and increasing the size of the bus bar for securing a portion to which the units are attached. Further, in the structure in which each of the plurality of units is attached to the bus bar, the assembling property is lowered and the working efficiency is lowered.

  The technology disclosed in the present application has been proposed in view of the above problems. An object of the present invention is to provide an output noise reduction device capable of improving filter characteristics and improving assemblability while reducing the size of the device.

  The output noise reduction device according to the technology disclosed in the present application, a bus bar extending in one direction, a plurality of arranged in the extending direction of the bus bar, each of a plurality of magnetic cores surrounding the bus bar, A conductive portion that is disposed between the plurality of magnetic cores in the extending direction and connects the ground terminal connected to the ground and the bus bar, a capacitor portion connected to the conductive portion, and a resin material, And a mold part for molding the conductive part and the capacitor part.

  In the output noise reduction device, the conductive portion connected between the bus bar and the ground is sandwiched between the plurality of magnetic cores in the extending direction. The output noise reduction device forms a T-type filter circuit with the capacitor portion connected to the conductive portion and the plurality of magnetic cores surrounding the bus bar, and reduces noise mixed in an output signal transmitted through the bus bar. In such a configuration, the resonance frequency of the filter circuit determined by the inductance of the plurality of magnetic cores, the capacitance of the capacitor, the ESL (equivalent series inductance) between the capacitor and the ground, and the like can be appropriately adjusted. In addition, the magnetic core is divided into a plurality of parts, and the conductive path between the capacitor and the ground is individually provided in parallel to increase the insertion loss related to the attenuation of noise contained in the output signal flowing through the bus bar, thereby increasing the filter characteristics. Can be improved. For this reason, compared with the case where the core which has the inductance of the same value as the value which totaled the inductance of the some magnetic body core was comprised with one member, a filter characteristic can be improved. In other words, in this configuration, by dividing into a plurality of cores, it is possible to improve the filter characteristics while making the total value of the inductance and capacitance the same value as before the division. As a result, even if magnetic cores having the same volume are used, the filter characteristics can be improved, and noise can be effectively reduced while downsizing the apparatus.

  The mold part molds the plurality of magnetic cores, the conductive part, and the capacitor part, and is integrated with the bus bar. As a result, by integrating a plurality of magnetic cores and capacitors divided to improve the filter characteristics with the bus bar, core misalignment or the like occurs when the output noise reduction device is attached. Can be suppressed. Therefore, in the output noise reduction device, it is possible to improve the assembling property while improving the filter characteristics and reducing the size.

  Further, in the output noise reduction device of the present application, the plurality of magnetic cores have a U-shaped cross-section cut along a plane orthogonal to the extending direction and a plurality of U-shaped cores extending through the bus bar. It is good also as a structure which has the rod-shaped core extended toward the direction and penetrated to the opening part of each of a some U-shaped core, and forms the magnetic flux path | route surrounding each circumference | surroundings of a bus-bar.

  In the output noise reduction device, a rod-shaped core is inserted into the openings of a plurality of U-shaped cores to form an annular magnetic core surrounding the bus bar. In such a configuration, the magnetic core can be attached to the bus bar by closing the openings of the plurality of U-shaped cores with the rod-shaped core while the bus bars are inserted into the plurality of U-shaped cores. For example, since the magnetic core can be attached to the bus bar even after the conductive portion is fixed to a part of the bus bar, the degree of freedom in the order of the manufacturing process and the degree of design can be improved. Moreover, the number of members can be reduced by sharing the rod-shaped core with a plurality of U-shaped cores.

  In the output noise reduction device of the present application, the plurality of magnetic cores may be arranged with a gap between at least one of the plurality of U-shaped cores and the rod-shaped core.

  In the output noise reduction device, a so-called core gap interposed in the magnetic flux path is provided between the U-shaped core and the rod-shaped core. Thereby, it becomes possible to increase the magnetic resistance of the plurality of magnetic cores to suppress the occurrence of magnetic saturation and to suppress the reduction of the filter characteristics.

  Further, in the output noise reduction device of the present application, the conductive portion is connected to the bus bar at the base end portion and extends between the plurality of magnetic cores in a direction perpendicular to the extending direction; A base end portion is connected to the bus bar, and is provided on the opposite side to the first conductive portion with at least one of the plurality of magnetic cores interposed therebetween in the extending direction, toward a direction parallel to the first conductive portion. At least one of the plurality of magnetic cores, the second conductive portion extending, and a connecting portion that connects the tip portions of the first conductive portion and the second conductive portion to each other and is connected to the ground terminal. Is inserted through an insertion hole that is surrounded by the first conductive part, the second conductive part, the connecting part, and the bus bar, and the mold part is the capacitor part, the first conductive part, the second conductive part, and the connecting part. A first mold part for molding the at least part of the bus bar, the first Rudo unit, and it may be configured to have a second mold part for molding a plurality of magnetic cores.

  In the output noise reduction device, the first and second conductive parts sandwiching the magnetic core in the extending direction are connected to the ground terminal via the connecting part. A π-type filter circuit can be configured by providing a capacitive part in both the first and second conductive parts. In addition, the magnetic core is inserted through an insertion hole formed by the first conductive portion or the like. Further, a part of the insertion hole (first conductive portion or the like) surrounding the magnetic core is molded by the first mold of the mold portion. Thereby, the attachment position with respect to the bus-bar of a magnetic body core can be clarified, and the improvement of attachment property can be aimed at. In addition, when the mounting position is displaced, the magnetic core inserted through the insertion hole comes into contact with the first mold portion and is restricted from moving, thereby preventing the displacement. The second mold part molds and integrates the magnetic core inserted through the insertion hole with a bus bar or the like. As a result, the core can be fixed while being inserted into the insertion hole and preventing displacement.

  Further, in the output noise reduction device of the present application, the conductive portion is a first conductive portion having a first ground terminal that is connected between the base end portion of the bus bar, inserted between the plurality of magnetic cores, and connected to the ground at the distal end portion. And a base end portion connected to the bus bar and provided on the opposite side of the first conductive portion across at least one of the plurality of magnetic cores in the extending direction and connected to the ground at the tip portion And a second conductive portion having two ground terminals.

  In the output noise reduction device, each of the first conductive portion and the second conductive portion provided with the magnetic core interposed therebetween in the extending direction includes a terminal connected to the ground. Here, when providing a common terminal that connects both the first and second conductive parts to the ground, the output noise reduction device is a common terminal that is a contact point with the ground when an external force is applied by an external impact or the like. There is a risk of stress concentration. For this reason, there is a possibility that the terminal is deformed at a portion where the stress is concentrated. On the other hand, in the output noise reduction device, by providing the first and second ground terminals for connecting to the ground in each of the first and second conductive parts, the stress caused by the external force or the like is dispersed, Terminal deformation and the like can be suppressed. In addition, a capacitance unit can be connected to each of the first conductive unit and the second conductive unit. For this reason, in the output noise reduction device, the total capacitance value between the bus bar and the ground, that is, the filter characteristics, is changed by individually changing whether or not each of the first and second ground terminals is connected to the ground. Can be adjusted.

  According to the output noise reduction device according to the technique disclosed in the present application, it is possible to improve the filter characteristics and improve the assembling property while reducing the size of the device.

It is the circuit diagram which connected the filter module which concerns on 1st Embodiment to the switching power supply. It is a perspective view of a filter module. It is a perspective view of a filter module, and is a figure showing the state where the 2nd mold part was removed. FIG. 4 is an exploded perspective view of the filter module shown in FIG. 3. It is a top view of the lead frame with the first mold part removed. FIG. 4 is a top view of the filter module shown in FIG. 3. FIG. 4 is a front view of the filter module shown in FIG. 3. It is a graph for comparing the filter characteristic with the case where a magnetic body core is multistage, and the case where it is not multistage. It is a perspective view of the filter module which concerns on 2nd Embodiment, Comprising: It is a figure which shows the state which removed the mold part. It is a perspective view of the magnetic body core of another example.

(First embodiment)
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a filter module 10 as an example of the output noise reduction device of the present application, and shows a circuit diagram in which the filter module 10 is connected to a connection point X of a switching power supply 15. The switching power supply 15 is housed in a metal casing 17 made of aluminum die casting or the like.

  First, the electrical operation effect regarding the filter module 10 is demonstrated using FIG. The switching power supply 15 is, for example, an in-vehicle power supply, and steps down the voltage value of a drive system power supply voltage VIN (for example, DC244V) supplied from a main battery (not shown) provided in a hybrid vehicle or an electric vehicle. This is a step-down switching power supply that supplies power to the auxiliary battery 19. The auxiliary battery 19 supplies a power supply voltage (for example, DC 14 V) to in-vehicle electrical equipment such as audio equipment, air conditioning equipment, and lighting equipment.

  In the switching power supply 15, a power transistor T and a diode D are connected in series between a power supply voltage VIN and a ground potential GND. The switching power supply 15 supplies power from a connection point X between the power transistor T and the diode D. The switching power supply 15 performs on / off control of the power transistor T at a predetermined switching frequency f based on the switching signal SW applied to the gate terminal of the power transistor T.

  The filter module 10 is configured as a π-type filter module in which a capacitor C0, a choke coil L1, and a capacitor C1 are connected between an input terminal VI and an output terminal VO. In the filter module 10, a choke coil L <b> 1 is provided in an output voltage path connecting the input terminal VI and the output terminal VO. In the choke coil L1, a capacitor C0 is connected between a connection point on the input side and the ground potential GND, and a capacitor C1 is connected between a connection point on the output side and the ground potential GND.

  A coil L0 is connected between the connection point X of the switching power supply 15 and the input terminal VI of the filter module 10. During the ON period of the power transistor T, power is supplied from the power supply voltage VIN to the coil L0, and electromagnetic energy is accumulated in the coil L0. The stored energy is released to the output side including the capacitor C0 of the filter module 10 by the current from the diode D during the off period of the power transistor T. In the switching power supply 15, these operations are repeatedly performed at a predetermined switching frequency f.

  In the switching power supply 15, a current corresponding to the load current alternately flows at the switching frequency f toward the connection point X via the power transistor T or the diode D. As a result, between the power supply voltage VIN and the ground potential GND, a current corresponding to the load current flows intermittently at the switching frequency f, causing fluctuations. Further, the potential at the connection point X is alternately switched between the power supply voltage VIN and the ground potential GND according to the switching frequency f. Therefore, in the switching power supply 15, the current fluctuation and voltage fluctuation due to the switching operation may become a noise source that generates switching noise of the switching frequency f and its harmonic frequency. Such switching noise may propagate to the input terminal VI as inductive noise that propagates through a space such as conductive noise or capacitive coupling that wraps around via a signal path or ground wiring.

  As described above, the filter module 10 of the present embodiment is connected to the connection point X via the coil L0. The filter module 10 reduces noise at the switching frequency f and its harmonic frequency resulting from the operation of the switching power supply 15. Here, the switching frequency f in the switching power supply 15 is determined according to the rating of the output power, the specifications of the elements constituting the circuit, and the like. For example, some on-vehicle switching power supplies operate at several hundred kHz. In this case, the switching frequency f and its harmonic frequency may overlap with the frequency band (around 500 to 1700 kHz) of the in-vehicle AM radio. On the other hand, the filter module 10 of the present embodiment is connected to the connection point X and can suppress the noise in these bands from propagating to the subsequent device.

  Next, the shape and structure of the filter module 10 will be described. FIG. 2 shows a perspective view of the filter module 10 shown in FIG. FIG. 3 shows a state where the mold part 23 (only the second mold part 52 described later) of the filter module 10 in FIG. 2 is removed.

  As shown in FIGS. 2 and 3, the filter module 10 includes a bus bar 21, a mold part 23, a lead frame 25, a magnetic core 27, and the like. The bus bar 21 is formed in a rectangular plate shape extending in one direction. In the following description, as shown in FIGS. 2 and 3, the extending direction of the bus bar 21 is the front-rear direction, the direction perpendicular to the front-rear direction and along the plane of the plate-like bus bar 21 is the left-right direction, the front-rear direction, and the left-right direction. A direction perpendicular to the plane of the bus bar 21 is referred to as an up-down direction.

  The bus bar 21 constitutes an output voltage path connecting the input terminal VI and the output terminal VO shown in FIG. The bus bar 21 is formed in a substantially rectangular shape extending in the front-rear direction when viewed from above (see FIG. 4). The bus bar 21 is made of, for example, a metal material such as tough pitch copper or aluminum. The bus bar 21 is formed with a terminal portion 31 having a rectangular shape when viewed from the up and down direction at an end portion on the front side (left side in FIGS. 2 and 3). The terminal portion 31 is formed with a circular connection hole 31A penetrating in the vertical direction. The terminal portion 31 constitutes the input terminal VI of FIG. 1 and is electrically connected to the connection terminal connected to the coil L0 by fastening the connection hole 31A with a bolt or the like.

  Further, the bus bar 21 is formed with a terminal portion 32 having a rectangular shape when viewed from the up and down direction at an end portion on the rear side (right side in FIGS. 2 and 3). The terminal portion 32 is formed with a circular connection hole 32A penetrating in the vertical direction. This terminal portion 32 constitutes the output terminal VO of FIG. 1, and is connected to the auxiliary battery 19 outside the metal housing 17 via a connection cable or the like. The mold part 23 is formed so as to cover the entire bus bar 21 excluding the terminal parts 31 and 32. The mold part 23 has a substantially box shape that is thin in the vertical direction. As a material of the mold part 23, for example, a thermosetting resin such as an epoxy resin or an unsaturated polyester, or a thermoplastic resin such as PBT or PPS can be used.

  FIG. 4 shows an exploded perspective view of FIG. As shown in FIG. 4, a core attachment portion 33 is formed between the bus bar 21 and the terminal portions 31 and 32 in the front-rear direction. The core attachment portion 33 has a plate shape extending along the front-rear direction while keeping the width in the left-right direction constant. The width of the core attachment portion 33 in the left-right direction is narrower than that of the terminal portions 31 and 32.

  The lead frame 25 includes a plurality (five in this embodiment) of fixing portions 41, ground terminal portions 43 and 44, and the like. The lead frame 25 is formed, for example, by punching a metal flat plate. The plurality of fixing portions 41 are arranged in parallel along the front-rear direction. Each of the fixing portions 41 is fixed to the upper surface 33 </ b> A of the core attachment portion 33. As a method of fixing the fixing portion 41 to the upper surface 33A, for example, a welding method (projection welding, spot welding, ultrasonic welding, etc.) can be used. The fixing method is not limited to welding, and may be a soldering method, a method using a conductive adhesive, or a fastening method using a bolt or the like.

  Each of the ground terminal portions 43 and 44 is disposed on the outer side in the left-right direction with respect to the fixed portion 41. Each of the fixed portions 41 and the left ground terminal portion 43, and a portion connecting each of the fixed portions 41 and the right ground terminal portion 44 are molded by the first mold portion 51 of the mold portion 23. The mold part 23 includes a first mold part 51 shown in FIG. 4 and a second mold part 52 (see FIG. 2) for molding the first mold part 51 and the magnetic core 27 (see FIG. 2). .

  FIG. 5 is a top view of the lead frame 25 and shows a state in which the first mold part 51 shown in FIG. 4 is removed. The lead frame 25 has connection portions 45 and 46 in addition to the plurality of fixing portions 41 and ground terminal portions 43 and 44 described above. The lead frame 25 has a symmetrical structure with respect to a straight line passing through the midpoint in the left-right direction and extending in the front-rear direction. Therefore, in the following description, the structure on the left side of the lead frame 25 will be mainly described, and the description of the structure on the right side will be omitted as appropriate.

  The lead frame 25 is formed of a metal material having good conductivity (for example, brass, copper, etc.). Each of the fixed portions 41 has a welded portion 41A and extended portions 41B and 41C. The welded portion 41A has a substantially circular shape when viewed from the vertical direction, and is fixed to the upper surface 33A of the above-described core mounting portion 33 by welding or the like.

  The extending portion 41B extends radially outward from the left outer peripheral portion of the circular welded portion 41A. The extending portion 41B extends along the left-right direction, and has a substantially rectangular shape that is long in the left-right direction when viewed from the up-down direction. The connection portion 45 has a substantially rectangular shape that is long in the left-right direction when viewed from the up-down direction.

  Five connection portions 45 on the left side are provided corresponding to the extending portions 41 </ b> B of the fixing portion 41. Similarly, five connecting portions 46 on the right side are provided corresponding to the extending portions 41 </ b> C of the fixing portion 41. Each of the connecting portions 45 is connected to the extending portion 41B by mounting the chip capacitor 61 thereon. The connecting portion 45 and the extending portion 41B are arranged in a state of being separated by providing a slit having a predetermined width between the left and right directions. The chip capacitor 61 is disposed so as to straddle the slit between the connecting portion 45 and the extending portion 41B. The chip capacitor 61 has one terminal connected to the left end of the extending portion 41 </ b> B and the other terminal connected to the right end of the connecting portion 45. The extension part 41B and the connection part 45 are molded by the first mold part 51 (see FIG. 4) and fixed in position with the chip capacitor 61 mounted. The chip capacitor 61 is surface-mounted on the upper surfaces of the extending portion 41B and the connecting portion 45 by, for example, soldering. The chip capacitor 61 is surface-mounted on the extended portion 41B and the connection portion 45, thereby omitting leads and shortening the connection distance, thereby reducing ESL (equivalent series inductance) and ESR (equivalent series resistance). It is illustrated.

  The ground terminal portion 43 includes a connecting portion 43A and a fastening plate portion 43B. The connecting portion 43 </ b> A has a plate shape extending along the front-rear direction in accordance with the position of the connecting portion 45. Accordingly, the front end portion of the connecting portion 43 </ b> A is located on the left side of the frontmost connection portion 45 among the five connection portions 45. Similarly, the rear end portion of the connecting portion 43 </ b> A is located on the left side of the rearmost connection portion 45 among the five connection portions 45.

  Each of the connecting portions 45 is connected to the connecting portion 43A by mounting the chip capacitor 62 thereon. In other words, the ground terminal portion 43 is electrically connected to all the connection portions 45 and the fixing portion 41 via the connecting portion 43A. Each of the connecting portions 45 and the connecting portion 43A are arranged in a state of being separated by providing a slit having a predetermined width between the left and right directions. The chip capacitor 62 is disposed so as to straddle the slit between the connecting portion 45 and the connecting portion 43A. The chip capacitor 62 has one terminal connected to the left end portion of the connection portion 45 and the other terminal connected to the right end portion of the coupling portion 43A. The connecting portion 45 and the connecting portion 43A are molded by the first mold portion 51 (see FIG. 4) and fixed in position with the chip capacitor 62 mounted. Similarly to the chip capacitor 61, the chip capacitor 62 is surface-mounted on the connection portion 45 and the connection portion 43A.

  The fastening plate portion 43B extends from the central portion in the front-rear direction of the connecting portion 43A toward the left side. The fastening plate portion 43B is formed toward the left side with a constant width in the front-rear direction, and the outer peripheral portion on the left side is formed in an arc shape. The front end portion of the fastening plate portion 43B corresponds to the position of the second connection portion 45 from the front among the five connection portions 45 arranged along the front-rear direction. The rear end portion of the fastening plate portion 43B corresponds to the position of the second connection portion 45 from the rear. Therefore, the width in the front-rear direction of the ground terminal portion 43 corresponds to the length in which the three connection portions 45 are arranged. The size, position, and shape of the fastening plate portion 43B described above are examples and can be changed as appropriate. For example, the width | variety of the front-back direction of the fastening plate part 43B may be a magnitude | size which opposes all the five connection parts 45 in the left-right direction.

  A circular fastening hole 43C penetrating in the vertical direction is formed in the left side portion of the fastening plate portion 43B. As shown in FIG. 2, the second mold part 52 of the mold part 23 is formed with an opening 52A that matches the position of the fastening hole 43C. A part of the ground terminal portion 43 is exposed from the opening 52A. The ground terminal portion 43 is fixed to the metal housing 17 by fastening a fastening member (such as a bolt) inserted into the fastening hole 43C to a screwed portion (not shown) of the metal housing 17. . The fastening member contacts and is electrically connected to a part of the ground terminal portion 43 exposed from the opening 52A.

  As shown in FIG. 5, the right portion of the lead frame 25 is configured in the same manner as the left portion. The extending portion 41 </ b> C is connected to the connecting portion 46 via the chip capacitor 64. The connecting portion 46 is connected to the connecting portion 44 </ b> A of the ground terminal portion 44 through the chip capacitor 65. The fastening plate portion 44B of the ground terminal portion 44 is fixed to the metal housing 17 by fastening the fastening member inserted through the fastening hole 44C to the screwed portion of the metal housing 17.

  Therefore, the filter module 10 shown in FIG. 2 is fixed to the metal casing 17 by a fastening member inserted through the ground terminal portions 43 and 44 in a state where the filter module 10 is molded by the second mold portion 52. The lead frame 25 is electrically connected to the metal casing 17 via a fastening member, and is supplied with a ground potential GND from the metal casing 17. As a result, a total of ten chip capacitors 61 and 62 are mounted between the fixed portion 41 fixed to the bus bar 21 and the left ground terminal portion 43. The ten chip capacitors 61 and 62 are mounted in parallel, with two chip capacitors 61 and 62 connected in series as one set. Similarly, a total of ten chip capacitors 64 and 65 are mounted between the fixed portion 41 and the right ground terminal portion 44. Chip capacitors 61, 62, 64, 65 constitute capacitors C1, C0 shown in FIG. The chip capacitors 61, 62, 64, 65 of this embodiment have the same capacitance.

  As shown in FIG. 5, the lead frame 25 has an insertion hole 71 formed in a portion surrounded by the fixing portion 41, the connection portion 45, and the connecting portion 43A. Similarly, an insertion hole 72 is formed in the lead frame 25 at a portion surrounded by the fixing portion 41, the connecting portion 46, and the connecting portion 44A. The insertion holes 71 and 72 have a substantially rectangular shape that is long in the left-right direction when viewed from the up-down direction.

  FIG. 6 shows a top view of FIG. As shown in FIG. 3, the first mold part 51 includes mold projecting parts 54 and 55 and mold connecting parts 57 and 58. The mold projecting portion 54 is a portion in which a part of the extending portion 41B, the connecting portion 45, and the chip capacitors 61 and 62 (see FIG. 5) are molded, and has a rectangular parallelepiped shape that is long in the left-right direction and thin in the front-rear direction. There is no. The mold protrusions 54 are formed in accordance with the positions of the connection portions 45 and the like, and a total of five are formed. The mold connecting portion 57 is a portion where the connecting portion 43A (see FIG. 5) is molded, and has a rectangular parallelepiped shape that is long in the front-rear direction and thin in the left-right direction. The first mold portion 51 has a comb-teeth shape that protrudes toward the right side when viewed from the top and bottom by connecting the left end portions of the five mold protrusion portions 54 with the mold connection portion 57. The insertion hole 71 described above is configured to be surrounded by two mold protrusions 54, a mold coupling portion 57, and the bus bar 21 that are adjacent in the front-rear direction.

  Similarly, each of the mold projecting portions 55 is molded with the connecting portion 46 and the like. The right end portions of the mold projecting portions 55 are connected by a mold connecting portion 58 that molds the connecting portion 44A (see FIG. 5). The five mold projecting portions 55 and the mold connecting portion 58 have a comb-teeth shape projecting toward the left side when viewed from the vertical direction. The above-described insertion hole 72 is configured to be surrounded by two mold projecting portions 55, a mold connecting portion 58, and the bus bar 21 that are adjacent in the front-rear direction.

  As shown in FIG. 4, the magnetic core 27 has four U-shaped cores 81 and one rod-shaped core 83. The plurality of U-shaped cores 81 have the same shape and have a substantially U shape having an opening on the upper side when viewed from the front-rear direction. The U-shaped core 81 has a plate shape with a predetermined thickness in the front-rear direction. As a material of the magnetic core 27, for example, a magnetic material such as soft ferrite can be used. The four U-shaped cores 81 of the present embodiment have the same inductance.

  The U-shaped core 81 has a bottom 81A and two projecting portions 81B and 81C. The bottom 81A has a plate shape formed along the left-right direction at the lower end of the U-shaped core 81. The protruding portion 81B has a plate shape extending upward from the upper end surface of the left end portion of the bottom portion 81A. The protrusion 81B is integrally formed with the bottom 81A. The protruding portion 81B is inserted from below into the insertion hole 71 formed by the mold protruding portion 54 of the first mold portion 51 described above.

  Similarly, the projecting portion 81C has a plate shape extending upward from the upper end surface of the right end portion of the bottom portion 81A. The protrusion 81C is integrally formed with the bottom 81A. The protruding portion 81 </ b> C is inserted from below into the insertion hole 72 configured by the mold protruding portion 55 of the first mold portion 51 described above.

  As shown in FIG. 3, the protruding portion 81 </ b> B and the protruding portion 81 </ b> C are fixed by the second mold portion 52 (see FIG. 2) in a state of protruding upward from the insertion holes 71 and 72. The rod-shaped core 83 has a rectangular parallelepiped shape that is long in the front-rear direction. The rod-shaped core 83 is inserted into the opening portions of the four U-shaped cores 81 fixed in the insertion holes 71 and 72. Also, the lateral width W1 of the protrusions 81B and 81C shown in FIG. 4 is from the inner end face (right end face) of the mold connecting portion 57 to the inner end face (left end face) of the mold connecting portion 58, as shown in FIG. The size is slightly smaller than the distance. Further, the width W2 in the left-right direction of each of the protrusions 81B and 81C is slightly smaller than the insertion holes 71 and 72.

  Further, the width W3 in the front-rear direction of each of the protrusions 81B, 81C is slightly smaller than the distance between the two mold protrusions 54, 55 adjacent in the front-rear direction. Accordingly, the protrusions 81B and 81C are inserted into the insertion holes 71 and 72, so that the outer peripheral surface is brought close to or in contact with the insertion holes 71 and 72. The U-shaped core 81 is restricted from moving in the front-rear direction and the left-right direction by the first mold part 51 in a state where the projecting parts 81B, 81C are inserted into the insertion holes 71, 72. Further, the protrusions 81 </ b> B and 81 </ b> C are held at positions separated from the core mounting part 33 and the rod-shaped core 83 disposed on the inner side in the left-right direction by being restricted in movement by the first mold part 51.

  Of the four fixed U-shaped cores 81, the rod-shaped core 83 is formed from a position facing the frontmost U-shaped core 81 to a position facing the rearmost U-shaped core 81. In other words, the magnetic core 27 of the present embodiment has U-shaped cores 81 that are divided (sliced) in the same shape with a predetermined width W3 (thickness) arranged in the front-rear direction, and is formed in the openings of the plurality of U-shaped cores 81. A rectangular parallelepiped bar core 83 is inserted. Further, the filter module 10 arranges chip capacitors 61, 62, 64, and 65 (see FIG. 5) having the same capacitance between the divided U-shaped cores 81, so that a π-type filter circuit is arranged in multiple stages. The arrangement is arranged.

  As shown in FIG. 4, three of the five mold protrusions 54 are sandwiched between the two mold protrusions 54 except for the frontmost and the rearmost ones. A stepped portion 54 </ b> A is formed in the mold protrusion 54. The step portion 54A is formed at the upper end portion of the right end portion of each mold protrusion 54. Similarly, of the five mold protrusions 55, the three mold protrusions 55 sandwiched in the front-rear direction are formed with step portions 55A. The step portion 55 </ b> A is formed at the upper end portion of the left end portion of each mold protrusion 55. The step portions 54A and 55A are formed to be recessed downward from the upper surface side of each of the mold projecting portions 54 and 55. The rod-shaped core 83 is placed on the step portions 54A and 55A. The rod-shaped core 83 is restricted from moving left and right and downward by the step portions 54A and 55A.

  FIG. 7 shows a front view of the filter module 10 shown in FIG. As shown in FIGS. 6 and 7, the rod-shaped core 83 is disposed at a position spaced upward from the bus bar 21 when placed on the stepped portions 54 </ b> A and 55 </ b> A. The bottom 81A is disposed at a position spaced downward from the bus bar 21. Further, the protruding portion 81 </ b> B and the protruding portion 81 </ b> C of the U-shaped core 81 are disposed with a predetermined gap between the protruding portion 81 </ b> B and the protruding portion 81 </ b> C with the core mounting portion 33 in the left-right direction. For this reason, the magnetic core 27 is disposed so as to surround the bus bar 21 with the U-shaped core 81 and the rod-shaped core 83, and is disposed with a predetermined gap between the magnetic core 27 and the bus bar 21. The magnetic core 27 constitutes the choke coil L1 (see FIG. 1) by inserting the bus bar 21 and arranging the inner side surface and the bus bar 21 to face each other.

  Further, the width W4 (see FIG. 4) in the left-right direction of the rod-shaped core 83 is slightly shorter than the distance between the protruding portions 81B, 81C in the left-right direction. For this reason, the rod-shaped core 83 is disposed with a gap 85 between the protrusions 81B and 81C in the left-right direction. In other words, the magnetic core 27 is divided into the rod-shaped core 83 and the U-shaped core 81 by the two gaps 85. The gap 85 is a so-called core gap, and a part of the magnetic path toward the circumferential direction of the magnetic core 27 is discontinuous. In the magnetic core 27, the magnetic resistance is adjusted by changing the width of the gap 85, for example, the width in the left-right direction of the rod-shaped core 83, thereby preventing magnetic saturation. Further, the filter module 10 can secure the inductance of the choke coil L1 necessary for removing the noise component by adjusting the width of the gap 85 of the magnetic core 27 to suppress the magnetic saturation. The magnetic core 27 may have a configuration in which a spacer having a predetermined magnetic permeability is inserted into the gap 85 and leakage flux generated from the gap 85 is suppressed.

<About improvement of filter characteristics>
As described above, the filter module 10 of the present embodiment has the chip capacitors 61, 62, 64, and 65 having the same capacitance disposed between the front and rear directions of the U-shaped core 81 divided into the same shape. A π-type filter circuit is arranged in multiple stages. Next, a description will be given of a comparison result of filter characteristics between the multi-stage filter module 10 and a multi-stage filter module having the same value of total inductance and capacitance. FIG. 8 shows a graph of the filter characteristics confirmed by performing the simulation under the above-described conditions.

  The vertical axis in FIG. 8 indicates the insertion loss related to the attenuation of noise conducted to the output voltage flowing through the bus bar 21. The horizontal axis indicates the frequency. A waveform 101 indicated by a solid line indicates a simulation result in a case where a multistage configuration corresponding to the filter module 10 of the present embodiment is configured. Further, a waveform 102 indicated by a broken line (“π-type filter” in the figure) shows a simulation result of the filter module of the first comparative example. Further, a waveform 103 (“π-type filter” in the figure) indicated by a one-dot chain line indicates a simulation result of the filter module of the second comparative example. The filter modules of the first and second comparative examples are composed of, for example, one magnetic material core 27 without being divided, and a magnetic material having the same inductance value as the total inductance value of the magnetic material core 27. It has a core. The width of the magnetic core in the front-rear direction is, for example, four widths (width W3 × 4) of the U-shaped core 81 shown in FIG.

  Further, in the filter module 10 of the present embodiment, a total of ten chip capacitors 61 and 62 are mounted between the bus bar 21 and the ground. The ten chip capacitors 61 and 62 are composed of two chip capacitors 61 and 62 connected in series, and five sets of chip capacitors 61 and 62 are connected in parallel. Similarly, five sets of chip capacitors 64 and 65 are connected in parallel between the bus bar 21 and the ground.

  On the other hand, in the filter module of the first comparative example, for example, one set of chip capacitors 61 and 62 and one set of chip capacitors 64 and 65 are connected in parallel to the preceding stage of the magnetic cores combined into one. Yes. Further, in the filter module of the first comparative example, for example, four sets of chip capacitors 61 and 62 and four sets of chip capacitors 64 and 65 are connected in parallel at the subsequent stage of the magnetic cores combined into one. In addition, in the filter module of the second comparative example, for example, two sets of chip capacitors 61 and 62 and two sets of chip capacitors 64 and 65 are connected in parallel at the preceding stage of the magnetic cores combined into one. Further, in the filter module of the second comparative example, for example, three sets of chip capacitors 61 and 62 and three sets of chip capacitors 64 and 65 are connected in parallel at the subsequent stage of the magnetic cores combined into one. For this reason, the filter modules of the first and second comparative examples have chip capacitors 61, 62, 64, and 65 that have the same total capacitance as the filter module 10 of the present embodiment between the core and the ground. Connected in parallel.

  As shown in FIG. 8, in each of the three waveforms 101 to 103, the insertion loss gradually increases from about 100 kHz to about 300 kHz. The waveforms 102 and 103 of the first and second comparative examples have the largest insertion loss at about 300 kHz, and thereafter the insertion loss gradually decreases. On the other hand, in the waveform 101 (the present embodiment), the insertion loss further increases after about 300 kHz, and the insertion loss is the largest between 400 kHz and 500 kHz. Further, the slope of the waveform 101 from about 100 kHz to about 300 kHz is steeper than the waveforms 102 and 103 of the first and second comparative examples. Therefore, in the specific frequency band (for example, AM band such as several hundred kHz), it can be considered that the configuration of the present embodiment has a high effect of suppressing noise.

  Furthermore, in the waveform 101 of this embodiment, the insertion loss increases to about −115 dB at about 400 kHz, and a remarkable noise reduction effect is obtained as compared with the waveforms 102 and 103 of the first and second comparative examples. I can confirm. Here, the shapes of the waveforms 101 to 103, that is, the filter characteristics are changed depending on various factors. For example, the number of sets of chip capacitors 61 and the like constituting the capacitor C0 (see FIG. 1) connected to the preceding stage of the choke coil L1 is 1 set in the case of the first comparative example and 2 sets in the case of the second comparative example. Become. On the other hand, in the case of the waveform 101 of the present embodiment, since the preceding stage of each choke coil L1 is one set, it is considered that the resonance frequency has increased even if the capacities of the individual chip capacitors 61 and the like are the same as in the comparative example. It is done. It is considered that the waveform 101 is shifted to the high frequency side as compared with the waveforms 102 and 103 of the first and second comparative examples because the resonance frequency is increased.

  In addition, the conductive path between the chip capacitor 61 and the like and the ground is formed for each capacitor portion and is parallelized, so that the ESL (equivalent series inductance) of the entire filter module 10 is reduced, and the order of the filter is increased by parallelization. As a result, it is considered that the waveform has become steep. As a result, the insertion loss is increased, and the filter characteristics are considered to be improved.

  The waveform shown in FIG. 8 is an example of a simulation result. In the filter module 10 of the present embodiment, it is possible to change the frequency band in which noise is desired to be suppressed to a desired frequency band (for example, an FM band) by changing the size of the inductance or capacitance. . As a result, the filter module 10 of the present embodiment can significantly improve the filter characteristics even in a frequency band different from the frequency band shown in FIG.

  Incidentally, in the said embodiment, the filter module 10 is an example of an output noise reduction apparatus. The lead frame 25 is an example of a conductive part. The connection parts 45 and 46 and the extension parts 41B and 41C are examples of the first conductive part and the second conductive part. Connection part 43A, 44A is an example of a connection part. The chip capacitors 61, 62, 64, 65 are an example of a capacitance unit.

  As described above in detail, in the filter module 10 according to the first embodiment disclosed in the present application, the connection portion 45 of the lead frame 25 connects the bus bar 21 and the ground terminal portions 43 and 44. A part of the connection portion 45 and the like is sandwiched between a plurality of U-shaped cores 81 surrounding the bus bar 21. In the filter module 10, a chip capacitor 61 and the like connected to the connection unit 45 and a plurality of U-shaped cores 81 constitute a π-type filter circuit, and reduce noise mixed in the output voltage transmitted through the bus bar 21. In such a configuration, the magnetic core 27 is divided, and the conductive path between the chip capacitor 61 and the like (capacitance unit) and the ground is arranged in parallel, thereby reducing the ESL of the entire circuit and increasing the filter order. The insertion loss of noise conducted to the output voltage flowing through 21 can be increased. For this reason, compared with the case where the core which has the inductance of the same value as the value which totaled the inductance of the several U-shaped core 81 or the rod-shaped core 83 is comprised with one member, a filter characteristic can be improved. As a result, even if magnetic cores having the same volume are used, the filter characteristics can be improved, and noise can be effectively reduced while downsizing the apparatus. In particular, in the automobile field, it is desired to reduce the size of this type of filter module 10 in a limited space from the viewpoint of securing a living space in the vehicle and reducing the weight of the automobile for improving fuel efficiency. Yes. For this reason, it is extremely effective to use the filter module 10 as a filter device such as an automobile power supply facility.

  The molded part 23 is integrated with the bus bar 21 by molding a plurality of U-shaped cores 81, rod-shaped cores 83, a part of the lead frame 25 (connecting parts 45 and the like), chip capacitors 61, and the like. As a result, a plurality of U-shaped cores 81 and the like divided to improve the filter characteristics are integrated with the bus bar 21, thereby suppressing the occurrence of core misalignment or the like when the filter module 10 is attached. can do. Therefore, in the filter module 10 of the present embodiment, the assembling property is improved while the filter characteristics are improved and the size is reduced.

  The magnetic core 27 is configured by inserting a rod-shaped core 83 into the openings of four U-shaped cores 81. In such a configuration, since the U-shaped core 81 and the like can be attached to the bus bar after the lead frame 25 is fixed to a part of the bus bar 21, the degree of freedom in the order of manufacturing processes and the degree of freedom in design can be improved. . Further, by sharing the rod-shaped core 83 with the four U-shaped cores 81, the number of members can be reduced.

  Further, the lead frame 25 is formed with an insertion hole 71 in a portion surrounded by the fixing portion 41, the connecting portion 45, and the connecting portion 43A (see FIG. 5). The insertion hole 71 is molded by the first mold part 51 and is surrounded by two mold protrusions 54, a mold connecting part 57, and the bus bar 21 that are adjacent in the front-rear direction (see FIG. 6). The U-shaped core 81 is inserted into the insertion hole 71 from below. As a result, the mounting positions of the four U-shaped cores 81 and the rod-shaped cores 83 with respect to the bus bar 21 are clarified to improve the mounting property. Moreover, when the mounting position shifts, the U-shaped core 81 inserted through the insertion hole 71 comes into contact with the first mold portion 51 and is restricted from moving, thereby preventing the position shift. The second mold part 52 molds and integrates the U-shaped core 81 inserted through the insertion hole 71 with the first mold part 51, the bus bar 21, and the like. Thereby, the U-shaped core 81 can be fixed to the bus bar 21 or the like while being inserted into the insertion hole 71 and preventing positional displacement.

(Second Embodiment)
Next, a second embodiment of the filter module of the present invention will be described. FIG. 9 is a perspective view of the filter module 10 </ b> A according to the second embodiment, and shows a state in which the mold part 23 (the first mold part 51 and the second mold part 52) is removed. In the filter module 10 of the first embodiment described above, the chip capacitors 62 and 65 are coupled to each other by the coupling portions 43A and 44A, and are connected to the ground terminal portions 43 and 44 that are common terminals. On the other hand, the filter module 10A of the second embodiment has the first terminal described above in that it has ground terminal portions 111 and 112 for connecting the chip capacitors 62 and 65 to the metal casing 17 (ground), respectively. It is different from the embodiment.

  In the following description, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted as appropriate. In addition, the filter module 10 </ b> A has a symmetrical configuration in the left-right direction, like the filter module 10. Therefore, in the following description, the structure on the right side (ground terminal portion 111 side) will be mainly described, and the description on the left side (ground terminal portion 112 side) will be omitted as appropriate. Further, an inner wall 17A shown in FIG. 9 shows a part of the metal casing 17 at a position where the filter module 10A housed in the metal casing 17 shown in FIG. 1 is arranged.

  The ground terminal portion 111 (an example of the first conductive portion and the second conductive portion) of the filter module 10 </ b> A is provided corresponding to each of the five chip capacitors 65. The ground terminal portion 111 has a plate shape, and includes a first extension terminal portion 111A extending in the vertical direction, a second extension terminal portion 111B extending in the left-right direction, and a fastening plate portion 111C (first ground terminal). And an example of a second ground terminal). The upper end portion of the first extension terminal portion 111A is connected to the right terminal of the chip capacitor 65. The first extension terminal portion 111A is bent downward from the upper end connected to the chip capacitor 65, and is formed along the vertical direction while keeping the width in the front-rear direction constant.

  The second extension terminal portion 111B is formed continuously with the lower end portion of the first extension terminal portion 111A and is bent toward the right side. The second extension terminal portion 111B is formed along the left-right direction with a constant width in the front-rear direction. Therefore, the ground terminal portion 111 has a substantially L shape when viewed from the front. The fastening plate portion 111C is formed at the right end portion of the second extension terminal portion 111B. The fastening plate portion 111C has an insertion hole for inserting a bolt or the like (not shown). The filter module 10A is fixed to the inner wall 17A of the metal casing 17 by bolts or the like inserted through the fastening plate portion 111C and supplied with a ground. A total of five ground terminal portions 111 connected to each chip capacitor 65 are arranged in parallel with a predetermined interval therebetween in the front-rear direction. The filter module 10 </ b> A is supplied with ground from the metal casing 17 through the ground terminal portions 111 and 112.

  In the filter module 10A of the second embodiment, the fastening plate portion 111C of the ground terminal portion 111 is disposed below the bus bar 21 or the like, so that, for example, the fastening plate is attached to the inner wall 17A of the metal housing 17 that houses the filter module 10A. The portions 111C can be arranged close to each other. Here, in the filter module 10 of the first embodiment, the fastening plate portions 43B and 44B of the ground terminal portions 43 and 44, the connecting portions 43A and 44A, the connecting portions 45 and 46, and the like are connected to the bus bar 21 and the chip capacitors 61 and 62. It was the structure arrange | positioned on the same plane. For example, in the filter module 10 according to the first embodiment, when the lower surface of the mold part 23 is disposed in contact with the inner wall 17A, the ground terminal parts 43 and 44 are positioned away from the inner wall 17A. For this reason, it is necessary to form the boss | hub part etc. which protrude upwards from 17 A of inner walls in the metal housing | casing 17, for example as a part which screws the volt | bolt inserted in the fastening holes 43C and 44C. Alternatively, in order to maintain the vertical distance between the inner wall 17A and the ground terminal portions 43 and 44, it is necessary to arrange a collar member through which a bolt is inserted between the ground terminal portions 43 and 44 and the inner wall 17A.

  In contrast, in the filter module 10A of the second embodiment, the fastening plate portion 111C is disposed below the bus bar 21 and the like so that the fastening plate portion 111C and the inner wall 17A are disposed close to each other in the vertical direction, and the boss portion It becomes possible to fix to the inner wall 17A satisfactorily without using the like. In addition, the shape of the ground terminal portions 111 and 112 of the second embodiment is an example, and can be changed as appropriate. For example, each of the plurality of ground terminal portions 111 may be formed along the left-right direction without being bent downward. In this case, the plurality of ground terminal portions 111 are arranged on the same plane as the bus bar 21. For example, a part or all of the ground terminal portions 111 and 112 may be formed of a conductive elastic body and grounded.

  Moreover, the filter module 10 of 1st Embodiment has the connection part 43A for connecting the five chip capacitors 62 with the one fastening plate part 43B. In this case, when an external force is applied to the filter module 10 by an external impact or the like, for example, stress concentrates on the fastening plate portion 43B that is a common portion. For this reason, there exists a possibility that the fastening plate part 43B may deform | transform etc. when stress concentrates.

  On the other hand, in the filter module 10A of the second embodiment, by providing the ground terminal portion 111 for connecting each of the chip capacitors 65 to the ground, the stress caused by an external force or the like is dispersed, and the ground terminal portion 111 Deformation and the like can be suppressed. Further, in the filter module 10A, the entire electrostatic capacitance value (filter characteristic) between the bus bar 21 and the ground is adjusted by connecting or not connecting each of the fastening plate portions 111C to the inner wall 17A (ground). be able to.

Needless to say, the technology disclosed in the present application is not limited to the above-described embodiment, and various improvements and modifications can be made without departing from the spirit of the present invention.
For example, the filter module 10 of the first embodiment has a configuration in which the five chip capacitors 62 are connected to the one fastening plate portion 43B by the connecting portion 43A, but is not limited thereto. For example, the lead frame 25 may include a ground terminal portion 43 for connecting a plurality of chip capacitors 62 to the metal housing 17 separately.

Moreover, in the said embodiment, although the some U-shaped core 81 was the structure which shares the one rod-shaped core 83, it is not restricted to this. For example, the rod-shaped core 83 may be divided into a plurality of parts according to the position and shape of each U-shaped core 81.
Further, the magnetic core 27 may be configured without the gap 85. For example, the magnetic core 27 may have a configuration in which a plurality of annular cores are arranged at predetermined intervals along the front-rear direction.

Moreover, in the said embodiment, although the filter module 10 alternately arrange | positioned the chip capacitor 61 grade | etc., And the U-shaped core 81 in the front-back direction, it is not restricted to this. For example, the filter module 10 may have a configuration in which the chip capacitors 61 and 62 are removed from any of the plurality of connection portions 45. For example, the filter module 10 may have a configuration in which an arbitrary U-shaped core 81 is removed from the plurality of U-shaped cores 81. By selectively removing the chip capacitors 61 and 62 and the U-shaped core 81 in this way, the filter module 10 can constitute an L-type or T-type filter circuit as well as a π-type. Further, the filter module 10 can adjust the filter characteristics by changing the number of the chip capacitors 61 and the U-shaped cores 81 and changing the constants of the inductance and the capacitance even if they have the same external appearance. Become.
In the above embodiment, two chip capacitors (for example, chip capacitors 61 and 62) are connected in series between the bus bar 21 and the ground. However, the present invention is not limited to this. For example, the filter module 10 may have a configuration in which one or three or more chip capacitors are connected between the bus bar 21 and the ground.
In the above embodiment, the chip capacitors 61, 62, 64, 65 are symmetrically arranged in the left-right direction with the bus bar 21 in between, but may be asymmetrically arranged.
Further, the chip capacitors 61, 62, 64, 65 may be electrostatic capacitance elements having different sizes. In this case, the filter module 10 can adjust the filter characteristics by attaching a plurality of filter circuits having different resonance frequencies to the bus bar 21.

Further, the capacitor portion in the present application is not limited to a chip capacitor, but may be an electric field capacitor, a film capacitor, or the like, or may be configured by combining them.
Moreover, in the said embodiment, although the fixing | fixed part 41 and the U-shaped core 81 were arrange | positioned at equal intervals in the front-back direction, you may arrange | position at different intervals.
Moreover, in the said embodiment, although the several U-shaped core 81 was provided with the gap 85 of the same width, the structure provided with the gap 85 of a different width | variety may be sufficient.

  Moreover, in the said embodiment, although the magnetic body core 27 was comprised combining the U-shaped U-shaped core 81 and the rectangular parallelepiped rod-shaped core 83, the shape etc. of the magnetic body core 27 are not restricted to this. . FIG. 9 shows a perspective view of another example of the magnetic core 27A. As shown in FIG. 9, the magnetic core 27 </ b> A includes two U-shaped cores 81 that are inverted in the vertical direction and are opposed to each other to form an annular core. The two U-shaped cores 81 are arranged with a gap 85 therebetween in the vertical direction. The gap 85 is a position facing the bus bar 21 (see FIG. 4), the connecting portion 43A (see FIG. 5), and the like in the left-right direction. Further, the gap 85 is a position facing the connecting portion 45, the chip capacitor 61 (see FIG. 5), and the like in the front-rear direction. In such a configuration, for example, an induction current is generated in the connecting portion 43A or the like by electromagnetic induction caused by leakage magnetic flux from the gap 85. Further, the induced current is generated in a direction opposite to the direction in which the noise current flowing through the connecting portion 43A toward the ground (the ground terminal portion 44 and the like), thereby canceling out part or all of the noise current. It becomes possible. As a result, the noise current is allowed to flow toward the ground by an amount that is offset by the induced current, and the noise can be further reduced.

In the above embodiment, the material of the magnetic core 27 is not limited to soft ferrite, and Sendust or amorphous magnetic alloy may be used.
In the above embodiment, the lead frame 25 and the metal casing 17 are connected by a fastening member such as a bolt in order to supply the ground potential GND. However, the present invention is not limited to this. For example, the ground potential GND may be supplied by connecting the lead frame 25 and the metal casing 17 by lead wiring. Alternatively, a part of the lead frame 25 may be extended and fixed directly to the metal housing 17.
In the above embodiment, the chip capacitor 61 and the like are mounted on the lead frame 25. However, the present invention is not limited to this. For example, the chip capacitor 61 or the like may be mounted on a resin substrate, and the resin substrate may be connected to the bus bar 21 or the ground terminal portion 43 or the like.
Moreover, the fixing method of the fixing | fixed part 41 and the bus-bar 21 is not restricted to welding, The method of fixing by screwing or caulking may be used.
The first mold part 51 and the second mold part 52 may be made of the same material or different materials.
Moreover, in the said embodiment, although the filter module 10 was accommodated in the metal housing | casing 17, it can change to the arbitrary positions of the transmission path | route of an output voltage not only in this. For example, the filter module 10 may be attached to the outer peripheral surface of the metal casing 17.
Moreover, the shape, number, etc. of each member in the said embodiment are examples, and can be changed suitably. For example, the bus bar 21 is not limited to a plate shape, and may be a cylindrical shape. Further, the molding unit 23 may be configured to mold only a part of the lead frame 25 without molding the entire lead frame 25.

  10 Filter module, 21 Bus bar, 27 Magnetic core, 25 Lead frame, 41B, 41C Extension part, 43, 44 Ground terminal part, 43A, 44A Connection part, 45, 46 Connection part, 61, 62, 64, 65 Chip Capacitor, 23 mold part, 51 first mold part, 52 second mold part, 71, 72 insertion hole, 81 U-shaped core, 83 bar-shaped core.

Claims (5)

A bus bar extending in one direction;
A plurality of magnetic cores arranged in the extending direction of the bus bar, each surrounding a periphery of the bus bar,
A conductive portion that is disposed between the plurality of magnetic cores in the extending direction and connects the ground terminal connected to the ground and the bus bar;
A capacitor connected to the conductive portion;
An output noise reduction device comprising: a plurality of magnetic cores, a mold part that molds the conductive part and the capacitor part, formed of a resin material.   The plurality of magnetic cores have a U-shaped cross-section cut along a plane orthogonal to the extending direction, and a plurality of U-shaped cores that pass through the bus bar, and extend in the extending direction. 2. A bar-shaped core that is inserted into an opening of each of the plurality of U-shaped cores and forms a magnetic flux path surrounding each of the plurality of U-shaped cores and the bus bar. The output noise reduction device described in 1.   3. The output noise reduction device according to claim 2, wherein the plurality of magnetic cores are disposed with a gap between at least one of the plurality of U-shaped cores and the rod-shaped core. The conductive portion includes a first conductive portion that is connected to the bus bar at a base end portion and extends between the plurality of magnetic cores in a direction orthogonal to the extending direction, and a base end portion of the bus bar. Connected in the extending direction and extending in a direction parallel to the first conductive portion provided on the opposite side of the first conductive portion with at least one of the plurality of magnetic cores interposed therebetween. A second conductive portion provided, and a connecting portion that connects the respective leading ends of the first conductive portion and the second conductive portion and is connected to the ground terminal,
At least one of the plurality of magnetic cores is inserted into an insertion hole that is surrounded by the first conductive portion, the second conductive portion, the connecting portion, and the bus bar,
The mold part includes a first mold part that molds the capacitor part, the first conductive part, the second conductive part, and the connection part, at least a part of the bus bar, the first mold part, and the plurality 4. The output noise reduction device according to claim 1, further comprising: a second mold part that molds the magnetic core.   The conductive portion includes a first conductive portion having a first ground terminal connected to the bus bar and having a first ground terminal inserted between the plurality of magnetic cores and connected to the ground at a distal end, and the bus bar. A second end connected to the ground at the front end and provided on the opposite side of the first conductive portion with at least one of the plurality of magnetic cores sandwiched therebetween in the extending direction. The output noise reduction device according to claim 1, further comprising a second conductive portion having a ground terminal.

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