Noise filter device

Abstract

A noise filter device according to the present invention comprises a busbar that is an electroconductive flat, plate-like member, a printed circuit board that has a wiring layer that is electrically connected to the busbar, a noise filter capacitor that is mounted on the printed circuit board and electrically connected to the wiring layer, and a flexible electroconductive member that is held between the busbar and the printed circuit board. The electroconductive member forms a linear electrical connection part between the busbar and the wiring layer along a busbar extension direction that is orthogonal to the plate thickness direction and the width direction of the busbar.

Description

Noise Filter Device

[0001] The present invention relates to an apparatus for suppressing electromagnetic noise.

[0002] Conventionally, motor drive systems have been used in electric vehicles such as electric cars and trains, in which DC power supplied from a DC power source is converted into AC power of a desired frequency and voltage by an inverter, and the AC power is output to the AC motor to drive the AC motor. In such motor drive systems, a relatively large current flows between the DC power source and the inverter, so they are generally electrically connected via a bus bar.

[0003] In a motor drive system, DC power is converted to AC power by the switching operation of the inverter, but the current flowing between the DC power supply and the inverter generates noise (electromagnetic noise) due to the inverter's switching operation. This noise needs to be suppressed as much as possible because it can have a negative effect on surrounding electronic devices.

[0004] Patent Literature 1 discloses a known technology for noise suppression in a motor drive system for an electric vehicle. Patent Literature 1 describes a filter including a circuit board mounted with a capacitor and having multiple conductive paths, a first conductive rail fixed on a first surface of the circuit board and electrically connected to at least one of the multiple conductive paths, and a second conductive rail fixed on a second surface of the circuit board and electrically connected to at least one of the multiple conductive paths. In this filter, the first and second conductive rails, which correspond to bus bars, are disposed on one surface (first surface) and the other surface (second surface) of the circuit board, respectively, thereby electrically connecting the conductive rails and the conductive paths of the circuit board with low inductance, thereby enhancing noise suppression.

[0005] Japanese Patent Application Publication No. 2018-50034

[0006] In the filter of Patent Document 1, the conductive rail is fixed to the circuit board using fixing means such as screws, brackets, or rivets, thereby electrically connecting the conductive rail and the conductive path of the circuit board. However, with this connection method, the designed contact area between the conductive rail and the conductive path of the circuit board is not always achieved due to various factors, such as dimensional errors and assembly errors of the conductive rail and the circuit board during manufacturing, warping or unevenness of their surfaces, and loosening of the fixing means due to continuous application of vibration during operation. As a result, the inductance between the conductive rail and the conductive path cannot be sufficiently reduced, and the desired noise suppression effect may not be achieved.

[0007] The present invention has been made in view of the above-mentioned problems, and a main object of the present invention is to provide a noise filter device that can stably exhibit a desired noise suppression effect.

[0008] A noise filter device according to the present invention comprises a bus bar made of a conductive flat member, a printed circuit board having a wiring layer electrically connected to the bus bar, a noise filter capacitor mounted on the printed circuit board and electrically connected to the wiring layer, and a flexible conductive member sandwiched between the bus bar and the printed circuit board, wherein the conductive member forms a linear electrical connection between the bus bar and the wiring layer along an extension direction of the bus bar that is perpendicular to the thickness and width directions of the bus bar.

[0009] According to the present invention, it is possible to provide a noise filter device that can stably exhibit a desired noise suppression effect.

[0010] FIG. 1 is a plan view of a noise filter device according to a first embodiment of the present invention. FIG. 2 is a view showing a state in which a magnetic core and a molded resin have been removed from FIG. 1 . FIG. 3 is a view showing an installation structure of a conductive member according to the first embodiment of the present invention. FIG. 4 is a cross-sectional view of a noise filter device according to the first embodiment of the present invention. FIG. 5 is a cross-sectional view of a noise filter device according to the first embodiment of the present invention. FIG. 6 is a cross-sectional view of a noise filter device according to the first embodiment of the present invention. FIG. 7 is a view showing a connection portion of a Y capacitor on a printed circuit board. FIG. 8 is a plan view of a noise filter device according to a second embodiment of the present invention. FIG. 9 is a cross-sectional view of a noise filter device according to the second embodiment of the present invention. FIG. 10 is a view showing a modified example of a noise filter device. FIG. 11 is a view showing an installation structure of a conductive member according to a third embodiment of the present invention. FIG. 12 is a cross-sectional view of a noise filter device according to the third embodiment of the present invention.

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0012] First Embodiment FIG. 1 is a plan view of a noise filter device 100 according to a first embodiment of the present invention. FIG. 2 is a diagram showing the state in which a magnetic core 107 and a molded resin 108 have been removed from FIG. 1 . FIG. 3 is a diagram showing an installation structure of a conductive member 106 according to a first embodiment of the present invention. FIGS. 4, 5, and 6 are cross-sectional views of the noise filter device 100 according to the first embodiment of the present invention. FIG. 4 shows the A-A' cross section of FIG. 1 , FIG. 5 shows the B-B' cross section of FIG. 1 , and FIG. 6 shows the C-C' cross section of FIG. 1 , respectively. FIG. 7 is a diagram showing the connection portion of Y capacitors 105a and 105b on a printed circuit board 103. The noise filter device 100 according to the first embodiment of the present invention will be described below with reference to these figures.

[0013] The noise filter device 100 is installed between a DC power supply such as a high-voltage battery and an inverter in, for example, a motor drive system mounted on a vehicle, to filter the current flowing between them and suppress unnecessary noise. As shown in Fig. 1, the noise filter device 100 includes a first bus bar 101, a second bus bar 102, a printed circuit board 103, an X capacitor 104, Y capacitors 105a and 105b, a conductive member 106 (not shown in Fig. 1), and a magnetic core 107.

[0014] The first bus bar 101 and the second bus bar 102, which are conductive flat-plate members, are arranged on top of each other with a printed circuit board 103 sandwiched therebetween. The surfaces of the first bus bar 101 and the second bus bar 102, except for their ends, are covered with molded resin 108, and the first bus bar 101 and the second bus bar 102 are fixed to each other by fixing members (e.g., screws) inserted into fixing holes 108a provided in the molded resin 108. The first bus bar 101 and the second bus bar 102 have mounting holes 101a and 102a, respectively, at both ends, and are connected to wiring in the motor drive system by connecting members (e.g., screws) inserted into the mounting holes 101a and 102a. As a result, the first bus bar 101 and the second bus bar 102 are electrically connected to the positive and negative sides, respectively, of a DC power supply in the motor drive system, and are also electrically connected to an inverter in the motor drive system.

[0015] The printed circuit board 103 is sandwiched between the first bus bar 101 and the second bus bar 102 and fixed in a predetermined positional relationship with respect to the first bus bar 101 and the second bus bar 102. The printed circuit board 103 has a first wiring layer 103a provided on the front surface side facing the first bus bar 101 and electrically connected to the first bus bar 101 via the conductive member 106, a second wiring layer 103b provided on the back surface side facing the second bus bar 102 and electrically connected to the second bus bar 102 via the conductive member 106, and a ground wiring layer 103c electrically connected to a ground potential. The first wiring layer 103a carries a current that flows between the first bus bar 101 and the X capacitor 104 or the Y capacitor 105a via the conductive member 106, and the second wiring layer 103b carries a current that flows between the second bus bar 102 and the X capacitor 104 or the Y capacitor 105b via the conductive member 106. The ground wiring layer 103c carries a current that flows between the first bus bar 101 and the Y capacitors 105a or 105b via the conductive member 106. That is, the first wiring layer 103a, the second wiring layer 103b, and the ground wiring layer 103c are flat conductors that extend two-dimensionally from the conductive member 106 to the X capacitor 104 or the Y capacitors 105a or 105b, respectively. These wiring layers 103a to 103c are insulated from each other on the printed circuit board 103.

[0016] The X capacitor 104 and the Y capacitors 105a and 105b are each disposed at a predetermined position on the printed circuit board 103. Specifically, the X capacitor 104 is disposed on one side (upper side in FIG. 1 ) of the conductive member 106 on the printed circuit board 103, side by side along the extension direction of the conductive member 106 (left-right direction in FIG. 1 ). The Y capacitors 105a and 105b are disposed on the other side (lower side in FIG. 1 ) of the conductive member 106 on the printed circuit board 103, side by side along the extension direction of the conductive member 106 (left-right direction in FIG. 1 ).

[0017] One end of the X capacitor 104 is electrically connected to the first wiring layer 103a, and the other end is electrically connected to the second wiring layer 103b. A via (through hole) (not shown) is provided in the printed circuit board 103 near the mounting position of the X capacitor 104, penetrating to the second wiring layer 103b on the back side. The X capacitor 104 is electrically connected to the second wiring layer 103b by connecting the other end of the X capacitor 104 to this via. This electrically connects the X capacitor 104 between the first bus bar 101 and the second bus bar 102, and the X capacitor 104 suppresses normal mode noise flowing through the first bus bar 101 and the second bus bar 102. Although three X capacitors 104 are arranged on the printed circuit board 103 in the example of FIG. 1 , the number of X capacitors 104 is not limited to this.

[0018] Ground wiring layers 103c are provided on both sides of the printed circuit board 103 near the mounting positions of the Y capacitors 105a and 105b, and through holes 109a are provided that penetrate these ground wiring layers 103c. For example, as shown in Figure 5, conductive connecting screws 109b are inserted into the through holes 109a, and the printed circuit board 103 is fixed via these connecting screws 109b to protrusions 109c provided on a portion of the motor drive system that has ground potential (for example, the housing). As a result, the ground wiring layers 103c are electrically connected to the protrusions 109c and are grounded.

[0019] 7, vias (through holes) 110a, 110b, 110c, and 110d are provided near the mounting positions of the Y capacitors 105a and 105b on the printed circuit board 103. The via 110a penetrates the first wiring layer 103a provided on the front side of the printed circuit board 103 and a pad provided on the back side and insulated from the ground wiring layer 103c. The via 110b penetrates the pad provided on the front side of the printed circuit board 103 and insulated from the ground wiring layer 103c, and the second wiring layer 103b provided on the back side. The vias 110c and 110d penetrate the ground wiring layers 103c provided on the front and back sides of the printed circuit board 103, respectively.

[0020] One end of the Y capacitor 105a is connected to the via 110a, thereby electrically connecting it to the first wiring layer 103a. The other end is connected to the via 110c, thereby electrically connecting it to the ground wiring layer 103c. Meanwhile, one end of the Y capacitor 105b is connected to the via 110b, thereby electrically connecting it to the second wiring layer 103b. The other end is connected to the via 110d, thereby electrically connecting it to the ground wiring layer 103c. As a result, the Y capacitors 105a and 105b are electrically connected between the first bus bar 101 and the second bus bar 102 and the ground potential, respectively, and common-mode noise flowing through the first bus bar 101 and the second bus bar 102 is suppressed.

[0021] The conductive member 106 has an elongated spiral shape along the extension direction (busbar extension direction) of the first bus bar 101 and the second bus bar 102, and is sandwiched between the first bus bar 101 and the front side (first wiring layer 103a side) of the printed circuit board 103, and between the second bus bar 102 and the back side (second wiring layer 103b side) of the printed circuit board 103. This allows the first bus bar 101 and the first wiring layer 103a, and the second bus bar 102 and the second wiring layer 103b to be electrically connected to each other via the conductive member 106.

[0022] 3, a metal plate formed in an elongated spiral shape is used for the conductive member 106. This provides flexibility to the conductive member 106 sandwiched between the first bus bar 101 and the first wiring layer 103a, and the conductive member 106 sandwiched between the second bus bar 102 and the second wiring layer 103b, thereby ensuring stable electrical connection therebetween.

[0023] Specifically, on the front surface side of the printed circuit board 103, as shown in, for example, Figures 3 and 6, an elongated, spiral-shaped conductive member 106 is placed in an insertion groove 101b formed along the bus bar extension direction on the surface of the first bus bar 101 facing the printed circuit board 103, and the first bus bar 101 and the printed circuit board 103 are then fixed together. By forming the insertion groove 101b so that the depth of the insertion groove 101b is smaller than the height of the conductive member 106, the conductive member 106 is sandwiched between the first bus bar 101 and the printed circuit board 103 in a state where it is slightly compressed in the vertical direction (direction perpendicular to the extension direction of the conductive member 106). As a result, as shown in Figure 3, an elongated, linear electrical connection portion 106a is formed between the conductive member 106 and the first wiring layer 103a of the printed circuit board 103 along the bus bar extension direction, which is perpendicular to the plate thickness and width directions of the first bus bar 101. For example, if the width of the first bus bar 101 is 15 mm or more, the electrical connection portion 106a may be formed with a smaller width of about 2 mm.

[0024] Similarly, on the back surface side of the printed circuit board 103, a conductive member 106 having an elongated spiral shape is placed in an insertion groove 102b formed along the bus bar extension direction on the surface of the second bus bar 102 facing the printed circuit board 103, and the second bus bar 102 and the printed circuit board 103 are then fixed together. By forming the insertion groove 102b so that the depth of the insertion groove 102b is smaller than the height of the conductive member 106, the conductive member 106 is sandwiched between the second bus bar 102 and the printed circuit board 103 in a state where it is slightly compressed in the vertical direction. As a result, an elongated linear electrical connection portion 106b is formed between the conductive member 106 and the second wiring layer 103b of the printed circuit board 103 along the bus bar extension direction, which is perpendicular to the plate thickness and width directions of the second bus bar 102.

[0025] The electrical connection portions 106a and 106b are formed elongated along the bus bar extension direction. As described above, the X capacitor 104 and the Y capacitors 105a and 105b are arranged side by side on the printed circuit board 103 along the extension direction of the conductive member 106. This structure shortens the paths of current flowing from the first bus bar 101 to the X capacitor 104 and the Y capacitor 105a via the conductive member 106 and the first wiring layer 103a, as shown by the arrows 111 in FIG. 2 . The same applies to the paths of current flowing from the second bus bar 102 to the X capacitor 104 and the Y capacitor 105b via the conductive member 106 and the second wiring layer 103b. As a result, the inductance of the noise current paths can be reduced, thereby improving the noise suppression effect.

[0026] Furthermore, a repulsive force is applied to electrical connection portions 106a and 106b from the crushed conductive member 106. This increases the adhesion between first bus bar 101 and second bus bar 102 and printed circuit board 103 at electrical connection portions 106a and 106b. Therefore, even if there is a slight dimensional error or assembly error between first bus bar 101 or second bus bar 102 and printed circuit board 103, if there is warping or unevenness on these surfaces, or if vibration is continuously applied during operation of noise filter device 100, it is possible to stably maintain the electrical connection state between first bus bar 101 and first wiring layer 103a at electrical connection portion 106a and the electrical connection state between second bus bar 102 and second wiring layer 103b at electrical connection portion 106b.

[0027] The magnetic cores 107 are arranged so as to surround the peripheries of the first bus bar 101 and the second bus bar 102, and suppress noise contained in the current flowing through the first bus bar 101 and the second bus bar 102. Note that, although the magnetic cores 107 are arranged at both ends of the first bus bar 101 and the second bus bar 102 in the example of Fig. 1, the number and positions of the magnetic cores 107 are not limited to this.

[0028] According to the first embodiment of the present invention described above, the following advantageous effects are achieved.

[0029] (1) The noise filter device 100 includes a first bus bar 101 and a second bus bar 102 each made of a conductive flat plate-like member, a printed circuit board 103 having a first wiring layer 103 a, a second wiring layer 103 b, and a ground wiring layer 103 c electrically connected to the first bus bar 101 and the second bus bar 102, an X capacitor 104 and a Y capacitors 105 a, 105 b for noise filtering mounted on the printed circuit board 103 and electrically connected to these wiring layers, and a flexible conductive member 106 sandwiched between the first bus bar 101 and the second bus bar 102 and the printed circuit board 103. The conductive member 106 forms linear electrical connection portions 106a, 106b between the first bus bar 101 and the first wiring layer 103a and between the second bus bar 102 and the first wiring layer 103a and the second wiring layer 103b, respectively, along the bus bar extension direction perpendicular to the plate thickness direction and width direction of the first bus bar 101 and the second bus bar 102. This makes it possible to stably maintain the electrical connection state between the first bus bar 101 and the first wiring layer 103a at the electrical connection portion 106a and the electrical connection state between the second bus bar 102 and the second wiring layer 103b at the electrical connection portion 106b, and as a result, it is possible to provide the noise filter device 100 that can stably exhibit the desired noise suppression effect.

[0030] (2) The first bus bar 101 and the second bus bar 102 have fitting grooves 101b and 102b, respectively, on the surfaces facing the printed circuit board 103. The conductive member 106 is disposed in the fitting grooves 101b and 102b. This configuration allows the conductive member 106 to be reliably pressed against the first wiring layer 103a and the second wiring layer 103b of the printed circuit board 103, thereby forming linear electrical connection portions 106a and 106b that extend in the bus bar extension direction.

[0031] (3) In the noise filter device 100, the plurality of capacitors 104, 105a, and 105b are arranged side by side along the bus bar extension direction on the printed circuit board 103. This arrangement shortens the path of current flowing from the first bus bar 101 and the second bus bar 102 to each capacitor via the conductive member 106 and each wiring layer, thereby improving the noise suppression effect by reducing the inductance of the noise current path.

[0032] (4) The first wiring layer 103a, the second wiring layer 103b, and the ground wiring layer 103c are flat conductors that extend two-dimensionally from the conductive member 106 to the X capacitor 104 and the Y capacitors 105a and 105b, respectively, and the current that flows between the first bus bar 101 or the second bus bar 102 and the X capacitor 104 or the Y capacitors 105a and 105b is passed through the first wiring layer 103a and the second wiring layer 103b via the conductive member 6. This makes it possible to further reduce the inductance of the noise current path.

[0033] (5) In the noise filter device 100, the first bus bar 101 is connected to the positive side of a DC power supply, and the second bus bar 102 is connected to the negative side of the DC power supply. The first wiring layer 103a is electrically connected to the first bus bar 101, the second wiring layer 103b is electrically connected to the second bus bar 102, and the ground wiring layer 103c is electrically connected to ground potential. The X capacitor 104 is connected to the first wiring layer 103a and the second wiring layer 103b, the Y capacitor 105a is connected to the first wiring layer 103a and the ground wiring layer 103c, and the Y capacitor 105b is connected to the second wiring layer 103b and the ground wiring layer 103c. This configuration makes it possible to suppress normal mode noise and common mode noise flowing through the first bus bar 101 and the second bus bar 102.

[0034] Second Embodiment In the first embodiment, an example was described in which electrical connection portions 106 a and 106 b were formed at one location each along the bus bar extension direction on the surfaces of first bus bar 101 and second bus bar 102 that face printed circuit board 103. In contrast to this, in the following second embodiment, an example will be described in which electrical connection portions 106 a and 106 b are formed at multiple locations along the bus bar extension direction.

[0035] Fig. 8 is a plan view of a noise filter device 100A according to a second embodiment of the present invention. Fig. 9 is a cross-sectional view of the noise filter device 100A according to the second embodiment of the present invention, showing the cross-section D-D' of Fig. 8. The noise filter device 100A according to the second embodiment of the present invention will be described below with reference to these drawings. Note that descriptions of parts of the noise filter device 100A that are common to the noise filter device 100 described in the first embodiment will be omitted.

[0036] In this embodiment, fitting grooves 101b are formed in two locations on the surface of the first bus bar 101 facing the printed circuit board 103 on the front side of the printed circuit board 103. Conductive members 106 are respectively disposed in the two fitting grooves 101b. As a result, parallel electrical connection portions 106a are respectively formed between each conductive member 106 and the first wiring layer 103a of the printed circuit board 103 along the extending direction of the bus bar.

[0037] Similarly, on the front surface side of the printed circuit board 103, fitting grooves 102b are formed in two locations on the surface of the second bus bar 102 that faces the printed circuit board 103. A conductive member 106 is disposed in each of the two fitting grooves 102b. As a result, parallel electrical connection portions 106b are formed between each conductive member 106 and the second wiring layer 103b of the printed circuit board 103 along the extending direction of the bus bar.

[0038] In this embodiment, the above-described structure makes it possible to further shorten the distances from the electrical connection portions 106 a and 106 b to the X capacitor 104 and the Y capacitors 105 a and 105 b than in the first embodiment, thereby further reducing the inductance of the noise current path and improving the noise suppression effect.

[0039] It is preferable that the electrical connection portion 106a formed on the front surface side of the printed circuit board 103 on the side of the Y capacitors 105a and 105b be provided over at least the entire area of ​​the portion where the distance from the center line of the width direction of the first bus bar 101 to the Y capacitor 105a is shortest. Similarly, it is preferable that the electrical connection portion 106b formed on the back surface side of the printed circuit board 103 on the side of the Y capacitors 105a and 105b be provided over at least the entire area of ​​the portion where the distance from the center line of the width direction of the second bus bar 102 to the Y capacitor 105b is shortest. In this way, it is possible to reliably reduce the inductance of the noise current path as described above, thereby improving the noise suppression effect.

[0040] According to the second embodiment of the present invention described above, the noise filter device 100A has a plurality of electrical connection portions 106a, 106b that are parallel to each other, thereby achieving a further improvement in the noise suppression effect.

[0041] (Modifications) In the first and second embodiments described above, the number and positions of the electrical connection portions 106a, 106b formed on the front and back sides of the printed circuit board 103 are not limited to the above examples. For example, as shown in FIG. 10 , two electrical connection portions 106a may be provided on the front side of the printed circuit board 103, while one electrical connection portion 106b may be provided on the back side of the printed circuit board 103. Furthermore, as shown in FIG. 11 , the positions of the electrical connection portion 106a on the front side of the printed circuit board 103 and the positions of the electrical connection portion 106b on the back side of the printed circuit board 103 may not overlap with each other in the thickness direction of the first bus bar 101 and the second bus bar 102. Even in these modifications, the same effects as those described in the first and second embodiments can be obtained.

[0042] Third Embodiment In the first and second embodiments, an example has been described in which a metal plate formed in an elongated spiral shape is used as the conductive member 106, and elongated linear electrical connection portions 106a, 106b are formed along the bus bar extension direction between the conductive member 106 and the first wiring layer 103a and the second wiring layer 103b of the printed circuit board 103, respectively. However, something other than this may be used as the conductive member 106.

[0043] A third embodiment of the present invention will be described below, in which a finger stock, which is a flexible metal gasket, is used as the conductive member 106. The external appearance and main configuration of the noise filter device according to this embodiment are the same as those of the first embodiment. Therefore, the following description will be given of an example in which the conductive member 106 of this embodiment is applied to the noise filter device 100 described in the first embodiment.

[0044] Fig. 12 is a diagram showing an installation structure of conductive member 106 according to the third embodiment of the present invention. Fig. 13 is a diagram showing a cross-sectional structure of first bus bar 101, second bus bar 102, printed circuit board 103, and conductive member 106 when conductive member 106 according to the third embodiment of the present invention is applied, and corresponds to Fig. 6 (the CC' cross-sectional view in Fig. 1) described in the first embodiment.

[0045] 13 , for example, the conductive member 106 is arranged so as to be sandwiched between the first bus bar 101 and the second bus bar 102 and the printed circuit board 103 and to be in close contact with them. Therefore, unlike the first embodiment, even if the fitting grooves 101b and 102b are not provided in the first bus bar 101 and the second bus bar 102, thin linear electrical connection portions 106a and 106b are formed between the conductive member 106 and the first wiring layer 103a and the second wiring layer 103b of the printed circuit board 103 along the bus bar extension direction perpendicular to the plate thickness direction and width direction of the first bus bar 101 and the second bus bar 102, respectively.

[0046] 12 and 13 show an example in which one electrical connection portion 106a is formed on the first bus bar 101 side and one electrical connection portion 106b is formed on the second bus bar 102 side, but a structure similar to that of the second embodiment and its modified examples described above may also be applied to this embodiment. That is, a finger stock may be used as the conductive member 106, and the electrical connection portions 106a and 106b may be formed at the positions shown in FIGS. 8 to 11.

[0047] According to the third embodiment described above, it is possible to obtain the same effects as those described in the first and second embodiments.

[0048] The present invention is not limited to the various embodiments and modifications described above, and includes various other modifications. For example, the above-described embodiments have been specifically described to clearly explain the present invention, and are not necessarily limited to those having all of the described configurations. Furthermore, part of the configuration of one embodiment can be replaced with part of the configuration of another embodiment. Furthermore, the configuration of another embodiment can be added to the configuration of one embodiment. Furthermore, part of the configuration of each embodiment can be deleted, and part of another configuration can be added or replaced with part of another configuration.

[0049] The present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the spirit of the present invention.

[0050] REFERENCE SIGNS LIST 100, 100A... Noise filter device 101... First bus bar 102... Second bus bar 103... Printed circuit board 104... X capacitor 105a, 105b... Y capacitor 106... Conductive member 107... Magnetic core 108... Molded resin

Claims

1. A noise filter device comprising: a bus bar made of a conductive flat member; a printed circuit board having a wiring layer electrically connected to the bus bar; a noise filter capacitor mounted on the printed circuit board and electrically connected to the wiring layer; and a flexible conductive member sandwiched between the bus bar and the printed circuit board, wherein the conductive member forms a linear electrical connection between the bus bar and the wiring layer along an extension direction of the bus bar that is perpendicular to the thickness and width directions of the bus bar.

2. A noise filter device according to claim 1, wherein the bus bar has a fitting groove on a surface facing the printed circuit board, and the conductive member is disposed in the fitting groove.

3. A noise filter device according to claim 1, wherein a plurality of the capacitors are arranged side by side along the extending direction of the bus bar.

4. A noise filter device according to claim 1, wherein the wiring layer has a flat conductor extending two-dimensionally from the conductive member to the capacitor.

5. A noise filter device according to claim 1, wherein the bus bars include a first bus bar connected to the positive electrode side of a DC power supply and a second bus bar connected to the negative electrode side of the DC power supply; the wiring layer includes a first wiring layer electrically connected to the first bus bar, a second wiring layer electrically connected to the second bus bar, and a ground wiring layer electrically connected to ground potential; and the capacitors include a second capacitor connected to the first wiring layer and the ground wiring layer, and a third capacitor connected to the second wiring layer and the ground wiring layer.

6. A noise filter device according to claim 1, comprising a plurality of said electrical connection parts arranged in parallel with each other.

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