Onboard power supply unit

Abstract

This invention provides an in-vehicle power supply device that allows for easy adjustment of the capacitance, which reduces parasitic capacitance in a common mode choke coil. [Solution] The on-board power supply unit comprises a power conversion unit, an input / output unit, and a noise filter unit equipped with a common mode choke coil 30. The common mode choke coil 30 comprises a coil body 301 and a cover member 40. The coil body 301 comprises an annular core, a core case 32 that houses the annular core and has a first positioning portion 36, and a first winding L1 and a second winding L2 wound around the core case 32. The cover member 40 comprises a conductor portion 46 and a second positioning portion 45. The second positioning portion 45 cooperates with the first positioning portion 36 to position the first winding L1 and the second winding L2 relative to the conductor portion 46 inside the cover member 40. The second positioning portion 45 maintains the gap formed between the first winding L1 and the second winding L2 and the conductor portion 46.

Description

Technical Field

[0001] The present invention relates to an in - vehicle power supply device.

Background Art

[0002] Conventionally, in - vehicle power supply devices are installed in vehicles such as electric vehicles that use an electric motor as a drive source. The in - vehicle power supply device may, for example, have a power conversion unit, an input / output unit, and a noise filter unit. In this case, the in - vehicle power supply device converts the power input from the input / output unit by the power conversion unit and then outputs it from the input / output unit. The noise filter unit is configured to reduce the conducted noise generated by the power conversion unit before it reaches the input / output unit. The noise filter unit may have a common - mode choke coil to reduce the common - mode noise included in the conducted noise.

[0003] The common - mode choke coil may be configured by winding a first winding and a second winding around a core case that houses an annular core. In this case, in the common - mode choke coil, each of the first winding and the second winding generates a parasitic capacitance, and the attenuation characteristics of the common - mode noise may deteriorate due to the parasitic capacitance.

[0004] Non - Patent Document 1 discloses a method of reducing the parasitic capacitance by connecting a capacitor with a capacitance corresponding to the parasitic capacitance between the mid - point of each of the first winding and the second winding of the common - mode choke coil and the ground. Also, Non - Patent Document 1 shows that the parasitic capacitance can be canceled by adjusting the capacitance of the capacitor to be four times the parasitic capacitance of the common - mode choke coil.

Prior Art Documents

Non - Patent Documents

[0005]

Non - Patent Document 1

[0006] In automotive power supply systems, it is desirable to be able to easily adjust the capacitance in a common-mode choke coil to reduce parasitic capacitance. [Means for solving the problem]

[0007] The in-vehicle power supply device for solving the above problems comprises: a power conversion unit that converts input power; an input / output unit that receives the power converted by the power conversion unit and outputs the power converted by the power conversion unit; and a noise filter unit electrically connected between the power conversion unit and the input / output unit and equipped with a common mode choke coil. The common mode choke coil comprises: a coil body having an annular core; a core case housing the annular core; a first winding wound around the core case; and a second winding wound around the core case at a distance from the first winding; and a cover member facing the coil body. The core case has a first positioning portion, and the cover member has a conductor portion facing the first and second windings and connected to the ground potential of the power conversion unit; and a second positioning portion that cooperates with the first positioning portion to position the first and second windings relative to the conductor portion inside the cover member and maintain the gap formed between the first and second windings and the conductor portion.

[0008] According to this, in the noise filter section, the common mode choke coil generates capacitance through the first and second windings of the coil body and the conductor portion of the cover member. This capacitance reduces the parasitic capacitance generated by each of the first and second windings in the common mode choke coil.

[0009] Furthermore, the coil body is positioned relative to the cover member through the cooperation of the first and second positioning sections. In other words, the gap between the first and second windings and the conductor is maintained at a constant size by the first and second positioning sections. As a result, the size of this gap can be adjusted, for example, by changing the dimensions of the cover member. That is, the size of this gap is easier to adjust compared to a case where, for example, the core case does not have a first positioning section and the cover member does not have a second positioning section. Since the capacitance generated by the first and second windings and the conductor is adjusted by the size of this gap, the capacitance can be easily adjusted in the on-board power supply unit with the above configuration. Therefore, the on-board power supply unit can easily adjust the capacitance that reduces parasitic capacitance in the common mode choke coil.

[0010] In an in-vehicle power supply device, the conductor portion may have a first conductor forming portion facing the first winding, and a second conductor forming portion facing the second winding and positioned at a distance from the first conductor forming portion.

[0011] According to this, the conductor portion is divided into a first conductor forming portion and a second conductor forming portion. As a result, the area of ​​the conductor portion can be reduced compared to, for example, the case where the conductor portion is provided over the entire portion of the cover member facing the first winding and the second winding. Furthermore, even if the shape of the portion of the cover member that becomes the second positioning portion is complex, the conductor portion can be provided only in the portions facing the first winding and the second winding, respectively, excluding that portion. As a result, in an on-board power supply unit, the conductor portion can be easily provided on the cover member compared to the case where the conductor portion does not have a first conductor forming portion and a second conductor forming portion.

[0012] Furthermore, in the above-described in-vehicle power supply unit, the creepage distance between the first and second windings can be increased compared to, for example, a case where a conductive portion is provided over the entire portion of the cover member facing the first and second windings.

[0013] In an in-vehicle power supply device, the cover member has a main body made of resin material on which the second positioning portion is provided, and the conductor portion is preferably a foil-like body provided on the portion of the main body facing the first winding and the second winding.

[0014] According to this, the cover member has a separate main body and a conductor. As a result, the on-board power supply unit can reduce manufacturing costs compared to, for example, a case where the cover member is made of a metal material with the conductor as part of it.

[0015] Furthermore, if, for example, the cover member and the conductor part are made of a metal material that is integrally molded, the entire portion of the cover member facing the first and second windings becomes the conductor. In other words, in the above-described in-vehicle power supply unit, the creepage distance between the first and second windings can be increased compared to, for example, the case where the cover member is made of a metal material in which the main body and the conductor part are integrally molded.

[0016] In an in-vehicle power supply device, the first positioning portion has a pair of bulges that bulge radially outward from the outer surface of the core case, with one bulge being located on the part of the core case opposite to the other bulge, and the second positioning portion has a projection that abuts against the pair of bulges radially outward from the annular core, and the core case is preferably held by the cover member by the pair of bulges fitting into recesses formed by the projection.

[0017] In an in-vehicle power supply device, the bulging portion is preferably included in a partition portion that separates the first winding and the second winding in the circumferential direction of the annular core. According to this, a partition provided in the core case to ensure the creepage distance between the first and second windings can be used as the first positioning section. As a result, by using a core case in which a partition is pre-provided to ensure the creepage distance, the on-board power supply unit can position the coil body relative to the cover member without any further processing of the core case.

[0018] In an in-vehicle power supply device, the core case may have a first winding section in which the first winding is tightly wound, and a second winding section in which the second winding is tightly wound. According to this, the on-board power supply unit can miniaturize the common mode choke coil compared to a case where, for example, the first winding and the second winding each form a portion where the first and second windings are not densely packed. Furthermore, the on-board power supply unit with the above configuration can reduce the leakage flux caused by that portion.

[0019] In an in-vehicle power supply unit, the gap is preferably set such that the capacitance generated by the conductor portion and the first and second windings is between 3 and 10 times the parasitic capacitance of the first and second windings, respectively.

[0020] The parasitic capacitance in the common mode choke coil is reduced compared to when the capacitance generated by the first and second windings and the conductor is not set as described above. In other words, the in-vehicle power supply unit with the above configuration can reduce the parasitic capacitance in the common mode choke coil.

[0021] In an in-vehicle power supply unit, the noise filter section may have a dielectric material placed in the gap. According to this, the capacitance generated by the first and second windings and the conductor can be adjusted not only by the distance between each of the first and second windings and the conductor, but also by the dielectric constant of the dielectric material. Therefore, compared to a case where the noise filter section does not have a dielectric material in the gap, the on-board power supply unit can easily adjust the capacitance generated by the first and second windings and the conductor.

[0022] In a vehicle-mounted power supply device, it may have a housing that houses the power conversion unit and the noise filter unit, and the cover member may constitute a part of the housing. According to this, the vehicle-mounted power supply device can provide a conductor portion in the housing, eliminating the need to add a separate component for providing the conductor portion to the vehicle-mounted power supply device. As a result, the vehicle-mounted power supply device with the above configuration can generate a capacitance for reducing the parasitic capacitance according to the parasitic capacitance of the common-mode choke coil while suppressing an increase in the number of components.

Effects of the Invention

[0023] According to the present invention, the capacitance for reducing the parasitic capacitance in the common-mode choke coil can be easily adjusted.

Brief Description of the Drawings

[0024] [Figure 1] FIG. 1 is a circuit diagram schematically showing a vehicle-mounted power supply device. [Figure 2] FIG. 2 is an equivalent circuit diagram showing a part of the noise filter unit. [Figure 3] FIG. 3 is an exploded perspective view showing a common-mode choke coil and a cover member. [Figure 4] FIG. 4 is a cross-sectional view showing a common-mode choke coil and a cover member. [Figure 5] FIG. 5 is a cross-sectional view showing a common-mode choke coil and a cover member in a modification example. [Figure 6] FIG. 6 is a cross-sectional view showing a common-mode choke coil and a cover member in a modification example. [Figure 7] FIG. 7 is a cross-sectional view showing a common-mode choke coil and a cover member in a modification example.

Modes for Carrying Out the Invention

[0025] Hereinafter, an embodiment of the vehicle-mounted power supply device will be described. The vehicle-mounted power supply device is mounted on a vehicle. The vehicle is, for example, an electric vehicle. <Overall view of the in-vehicle power supply system> As shown in Figure 1, the on-board power supply unit 10 is electrically connectable to an external power source E. The external power source E is located outside the vehicle. The external power source E is an AC power source that outputs AC power. The external power source E is, for example, a vehicle charging station. The on-board power supply unit 10 is electrically connected to a battery B mounted on the vehicle. The battery B is a power source that supplies power to the vehicle's drive motor and on-board electrical equipment (not shown). The on-board power supply unit 10 in this embodiment is an on-board charging device that converts the AC power supplied from the external power source E into DC power and then supplies it to the battery B.

[0026] The on-board power supply unit 10 includes a power conversion unit 11, an input / output unit 12, a control device 13, and a noise filter unit 20. The on-board power supply unit 10 connects the power conversion unit 11, the input / output unit 12, and the noise filter unit 20 by a first wiring EL1 and a second wiring EL2, respectively.

[0027] The power conversion unit 11 has a plurality of switching elements (not shown). The power conversion unit 11 is configured to convert the input power through the switching operation of these switching elements. In other words, the power conversion unit 11 converts the input power. The power conversion unit 11 is also configured to output the converted power.

[0028] The power conversion unit 11 in this embodiment functions as a combination of an AC / DC converter and a bidirectional DC / DC converter. More specifically, the power conversion unit 11 converts the input AC power into DC power. Furthermore, the power conversion unit 11 converts the DC power to a desired voltage. In other words, the power conversion unit 11 converts the input AC power into DC power having a desired voltage and outputs it.

[0029] The input / output unit 12 is composed of input terminals 12a and output terminals 12b. The input / output unit 12 in this embodiment has a pair of input terminals 12a and a pair of output terminals 12b. The number of input terminals 12a and output terminals 12b in the input / output unit 12 is not limited to this embodiment. Of the pair of input terminals 12a, one input terminal 12a is connected to the first wiring EL1, and the other input terminal 12a is connected to the second wiring EL2. Of the pair of output terminals 12b, one output terminal 12b is connected to the first wiring EL1, and the other output terminal 12b is connected to the second wiring EL2.

[0030] The input terminal 12a can be connected to an external power supply E. In other words, the vehicle power supply unit 10 can be connected to an external power supply E via the input terminal 12a. AC power supplied from the external power supply E is input to the input terminal 12a. The output terminal 12b is connected to the battery B. In other words, the vehicle power supply unit 10 is connected to the battery B via the output terminal 12b.

[0031] The AC power input to input terminal 12a is input to the power conversion unit 11 via the first wiring EL1 and the second wiring EL2, respectively. This AC power is converted to DC power of the desired voltage by the power conversion unit 11, and then output to the battery B from output terminal 12b via the first wiring EL1 and the second wiring EL2. In other words, the input / output unit 12 receives power converted by the power conversion unit 11 as input, and outputs power converted by the power conversion unit 11 as output.

[0032] The control device 13 controls multiple switching elements included in the power conversion unit 11. The power conversion unit 11 converts the input AC power into DC power through the control of the switching elements by the control device 13, and outputs the DC power to the battery B.

[0033] <Noise filter section> The noise filter unit 20 is electrically connected between the power conversion unit 11 and the input / output unit 12. More specifically, the noise filter unit 20 is provided between the input terminal 12a and the power conversion unit 11, and between the power conversion unit 11 and the output terminal 12b. In other words, the in-vehicle power supply unit 10 of this embodiment has two noise filter units 20. Hereafter, the noise filter unit 20 provided between the input terminal 12a and the power conversion unit 11 will be referred to as the first noise filter unit 20. The noise filter unit 20 provided between the power conversion unit 11 and the output terminal 12b will be referred to as the second noise filter unit 20.

[0034] The first noise filter unit 20 is electrically connected to the input terminal 12a and the power conversion unit 11, respectively, by the first wiring EL1 and the second wiring EL2. Power is input to the first noise filter unit 20 from the input terminal 12a via the first wiring EL1 and the second wiring EL2. In other words, AC power is input to the first noise filter unit 20.

[0035] The second noise filter unit 20 is electrically connected to the power conversion unit 11 and the output terminal 12b, respectively. Power is input to the second noise filter unit 20 from the power conversion unit 11 via the first wiring EL1 and the second wiring EL2. In other words, DC power is input to the second noise filter unit 20.

[0036] Figure 2 shows a portion of the noise filter section 20. The noise filter section 20 includes a common-mode choke coil 30, an X capacitor 21, and a pair of Y capacitors 22. In other words, the noise filter section 20 includes a common-mode choke coil 30.

[0037] The X capacitor 21 is connected to the first wiring EL1 and the second wiring EL2. The pair of Y capacitors 22 are connected in series to each other, forming a series circuit of Y capacitors 22. The X capacitor 21 and this series circuit are connected in parallel. The midpoint of the pair of Y capacitors 22 is connected to ground.

[0038] The noise filter section 20 reduces conducted noise flowing in through the first wiring EL1 and the second wiring EL2. More specifically, the noise filter section 20 reduces normal mode noise from the conducted noise using the X capacitor 21. Furthermore, the noise filter section 20 reduces common mode noise from the conducted noise using the Y capacitor 22 and the common mode choke coil 30, which will be described in detail later.

[0039] Note that the circuit diagram shown in Figure 2 is only a part of the noise filter section 20. In other words, the noise filter section 20 may have multiple common mode choke coils 30, multiple X capacitors 21, and multiple Y capacitors 22. Also, the connection order of the common mode choke coils 30, X capacitors 21, and Y capacitors 22 in the noise filter section 20 may differ from that shown in Figure 2. Furthermore, the configuration of the X capacitors 21, Y capacitors 22, and common mode choke coils 30 may differ between the first noise filter section 20 and the second noise filter section 20. In short, the noise filter section 20 just needs to be configured to reduce conducted noise.

[0040] <Common mode choke coil body> As shown in Figures 3 and 4, the common mode choke coil 30 comprises a coil body 301 and a cover member 40. The coil body 301 has an annular core 31, a core case 32, a first winding L1, and a second winding L2. The annular core 31 is formed of a magnetic material.

[0041] Each of the first winding L1 and the second winding L2 is wound around a single annular core 31 via a core case 32. The winding directions of the first winding L1 and the second winding L2 are opposite to each other. The first winding L1 is connected in series with the first wiring EL1. The second winding L2 is connected in series with the second wiring EL2.

[0042] Therefore, in Figure 1, the input terminal 12a is connected to the power conversion unit 11 via the first wiring EL1 and the first winding L1 shown in Figure 2, and also via the second wiring EL2 and the second winding L2 shown in Figure 2. The power conversion unit 11 is connected to the output terminal 12b via the first wiring EL1 and the first winding L1 shown in Figure 2, and also via the second wiring EL2 and the second winding L2 shown in Figure 2.

[0043] As shown in Figure 3, the common mode choke coil 30 is mounted on the circuit board 14 with the coil body 301 housed in a cover member 40, which will be described in detail later. The circuit board 14 is mounted with the electronic components that constitute the input / output unit 12 and the power conversion unit 11, as shown in Figure 1. More specifically, the circuit board 14 is mounted with the input terminal 12a, the output terminal 12b, and several switching elements (not shown) shown in Figure 1.

[0044] The core case 32 is annular in shape. The core case 32 is made of resin and is insulating. The core case 32 houses the annular core 31. For example, the core case 32 is formed by dividing it into two members (not shown) on a plane perpendicular to the axial direction of the annular core 31, and the annular core 31 is housed by covering and integrating these two members. The circumferential and radial directions of the core case 32 coincide with the circumferential and radial directions of the annular core 31, respectively.

[0045] The core case 32 has an inner circumferential surface 321, an outer circumferential surface 322, and two end faces 323. The outer surface of the core case 32 consists of the inner circumferential surface 321, the outer circumferential surface 322, and the two end faces 323. The inner circumferential surface 321 is the surface that defines the through hole of the core case 32. The outer circumferential surface 322 is the surface opposite the inner circumferential surface 321 in the radial direction of the core case 32. Each of the two end faces 323 is the surface that connects the inner circumferential surface 321 and the outer circumferential surface 322. The through hole of the core case 32 is open at each of the two end faces 323.

[0046] The core case 32 has a partition portion 33, a first winding portion 34, and a second winding portion 35 on its outer surface. The first winding portion 34 and the second winding portion 35 are arranged in the circumferential direction of the core case 32. The partition portion 33 is interposed between the first winding portion 34 and the second winding portion 35.

[0047] The partition portion 33 extends along the diameter of the core case 32. More specifically, the partition portion 33 extends across the through hole of the core case 32 in the diametrical direction of the core case 32. The partition portion 33 divides the core case 32 into a first winding portion 34 and a second winding portion 35.

[0048] The partition section 33 has a pair of bulging sections 331 and a partition wall section 332. In other words, the bulging sections 331 are included in the partition section 33. The pair of bulging sections 331 are aligned radially in the core case 32.

[0049] The bulge 331 is a portion of the core case 32 that protrudes radially from the outer circumferential surface 322 of the core case. In other words, the bulge 331 is a portion of the annular core 31 that bulges radially on the outer surface of the core case 32. Furthermore, the bulge 331 is also formed on the end face 323 of the core case and has a bulging portion on the end face 323 of the core case. In short, the bulge 331 is a portion that bulges from the outer surface of the core case 32.

[0050] The pair of bulges 331 are formed on the core case 32 in portions that are separated from each other in the circumferential direction of the core case 32. One of the pair of bulges 331 is located on the portion of the core case 32 opposite to the other bulge 331. More specifically, the pair of bulges 331 are arranged in the core case 32 so that one bulge 331 and the other bulge 331 are aligned in the radial direction of the core case 32. In other words, the pair of bulges 331 face each other across a through hole in the core case 32.

[0051] The core case 32 has a first winding section 34 between one bulge 331 and the other bulge 331 in the circumferential direction of the core case 32. The core case 32 also has a second winding section 35 located between the one bulge 331 and the other bulge 331, and in a different location from the first winding section 34. The first winding section 34 and the second winding section 35 are adjacent to each other in the circumferential direction of the core case 32, with the bulge 331 interposed between them. The pair of bulge sections 331 separate the first winding L1 and the second winding L2. In other words, the partition section 33 separates the first winding L1 and the second winding L2.

[0052] The partition wall portion 332 is a plate-like body extending from one bulge portion 331 toward the other bulge portion 331. The partition wall portion 332 divides the through-hole of the core case 32 into two regions. The partition 33 is provided in the core case 32 to ensure a creepage distance between the first winding L1 and the second winding L2. More specifically, the core case 32 provides a partition 33 between the first winding L1 and the second winding L2, thereby ensuring a creepage distance between the first winding L1 and the second winding L2 equal to the size of the partition 33.

[0053] The core case 32 has a first positioning portion 36. The coil body portion 301 also has a first positioning portion 36. The first positioning portion 36 is provided on the core case 32. The first positioning portion 36 has a pair of bulging portions 331. In this embodiment, the first positioning portion 36 is composed of a pair of bulging portions 331. In other words, the core case 32 can be said to ensure the creepage distance between the first winding L1 and the second winding L2 by the first positioning portion 36.

[0054] The coil body 301 is formed by winding a first winding L1 and a second winding L2 around a core case 32 that houses an annular core 31. The first winding L1 is wound around the first winding section 34 of the core case 32. In other words, the first winding L1 is wound around the core case 32. The second winding L2 is wound around the second winding section 35 of the core case 32. In other words, the second winding L2 is wound around the core case 32 at a distance from the first winding L1.

[0055] More specifically, the first winding section 34 is densely wound with the first winding wire L1. The second winding section 35 is densely wound with the second winding wire L2. In this specification, "densely wound" means that the windings are wound so that the number of turns per unit length is maximized when the windings are wound without overlapping in the direction in which the member on which the windings are wound extends. In this embodiment, "densely wound with the first winding wire L1" means that the first winding wire L1 is wound around the first winding section 34 so as to cover the entire portion of the inner circumferential surface 321 of the core case that corresponds to the first winding section 34. Furthermore, "densely wound with the second winding wire L2" means that the second winding wire L2 is wound around the second winding section 35 so as to cover the entire portion of the inner circumferential surface 321 of the core case that corresponds to the second winding section 35.

[0056] Each end of the first winding L1 is adjacent to the first winding portion 34 side of one of the bulging portions 331 located on the lower substrate 14 side in Figure 3, in the circumferential direction of the core case 32, and extends radially to the core case 32. Note that in Figure 3, one end of the first winding L1 is shown, but the other end is not. Furthermore, each end of the second winding L2 is adjacent to the second winding portion 35 side of the bulging portion 331, in the circumferential direction of the core case 32, in a portion different from the portion adjacent to the first winding L1, and extends radially to the core case 32.

[0057] Each of the first winding L1 and the second winding L2 has parasitic capacitance. In Figure 2, the parasitic capacitance of each of the first winding L1 and the second winding L2 is represented as a virtual capacitor CP having that parasitic capacitance.

[0058] <Cover component for common mode choke coil> As shown in Figures 3 and 4, the common mode choke coil 30 has a cover member 40. The common mode choke coil 30 in this embodiment has two cover members 40. The cover member 40 has a main body portion 41 and a conductor portion 46.

[0059] The main body 41 is made of resin. The main body 41 has a peripheral wall 42 and an end wall 43. The peripheral wall 42 is cylindrical. An end wall 43 is provided at the first end of the peripheral wall 42 in the axial direction. The peripheral wall 42 is open to the outside at its second end.

[0060] The main body 41 has a storage space 41a defined by a peripheral wall 42 and an end wall 43. The storage space 41a is closed off by the end wall 43 at the first end of the peripheral wall 42 and opens to the outside of the main body 41 at the second end of the peripheral wall 42.

[0061] The main body portion 41 has two slits 44. The two slits 44 are formed in the peripheral wall 42. The slits 44 extend in the axial direction of the peripheral wall 42 from the first end to the second end of the peripheral wall 42. The two slits 44 are provided in the peripheral wall 42 so as to be parallel to each other in the circumferential direction of the peripheral wall 42. The slits 44 connect the housing space 41a and the outside of the main body portion 41 in the thickness direction of the peripheral wall 42.

[0062] The main body 41 has a second positioning portion 45. In other words, the cover member 40 has a second positioning portion 45. The second positioning portion 45 is located in the housing space 41a. The second positioning portion 45 has a pair of protrusions 45a provided on the peripheral wall 42 and a groove 45b provided on the end wall 43. That is, the second positioning portion 45 has protrusions 45a.

[0063] The protrusions 45a are portions of the peripheral wall 42 that project radially inward from the inner surface of the peripheral wall 42. The pair of protrusions 45a are formed on portions of the peripheral wall 42 that face each other in the radial direction of the peripheral wall 42. In other words, the pair of protrusions 45a are portions of the peripheral wall 42 that face each other across the housing space 41a and project radially inward from the peripheral wall 42. The protrusions 45a divide the inner surface of the peripheral wall 42 into two parts in the circumferential direction of the peripheral wall 42.

[0064] The projection 45a extends from the first end to the second end of the peripheral wall 42 in the axial direction of the peripheral wall 42. The end of the projection 45a closer to the first end of the peripheral wall 42 is connected to the end wall 43. Therefore, it can be said that the projection 45a is erected on the end wall 43.

[0065] One of the pair of protrusions 45a is adjacent to and sandwiched between two slits 44 in the circumferential direction of the peripheral wall 42. In other words, one of the protrusions 45a is formed in the portion of the peripheral wall 42 that lies between the two slits 44.

[0066] The pair of protrusions 45a form a recess 45c. The recess 45c is the portion of the cover member 40 located between the pair of protrusions 45a. The distance between the opposing surfaces of the pair of protrusions 45a in the radial direction of the peripheral wall 42 is slightly larger than the outer diameter of the portion of the core case 32 in which the pair of bulges 331 are formed.

[0067] The groove 45b is formed on the surface of the end wall 43 that faces inward towards the circumferential wall 42. The groove 45b extends radially along the circumferential wall 42. The groove 45b is formed to traverse the end wall 43 in that radial direction. Therefore, the groove 45b divides the surface of the end wall 43 that faces inward towards the circumferential wall 42 into two parts in a direction perpendicular to the direction in which the groove 45b extends. The groove 45b is formed by two plate-like bodies erected on the end wall 43, which are spaced apart in the thickness direction of the plate-like bodies.

[0068] Of the groove portion 45b, both ends in the radial direction of the peripheral wall 42 are connected to the protrusion portion 45a. Therefore, the storage space 41a is divided into two spaces, with the protrusion portion 45a and the groove portion 45b in between. In other words, the storage space 41a is divided into two spaces by the second positioning portion 45. Each of these two spaces has one slit 44.

[0069] The groove 45b constitutes a part of the recess 45c. More specifically, the recess 45c is the portion of the cover member 40 where the pair of protrusions 45a form the sides and the groove 45b forms the bottom.

[0070] The conductor portion 46 is a foil-like body made of metal. In this embodiment, the conductor portion 46 is copper foil. The conductor portion 46 is provided on the inner circumferential surface of the peripheral wall 42 and on the surface of the end wall 43 that faces the direction of the housing space 41a. More specifically, the conductor portion 46 is provided to cover the portion of the inner circumferential surface of the peripheral wall 42 excluding the two slits 44 and the protrusion 45a. The conductor portion 46 is also provided to cover the portion of the surface of the end wall 43 that faces the direction of the housing space 41a excluding the groove 45b. As described above, the conductor portion 46 covers the portion of the surface defining the housing space 41a in the main body portion 41 excluding the slits 44 and the second positioning portion 45.

[0071] The conductor portion 46 covers the end face of the peripheral wall 42 at its second end, perpendicular to the axial direction of the peripheral wall 42. The conductor portion 46 has a first conductor forming portion 461 and a second conductor forming portion 462. The first conductor forming portion 461 and the second conductor forming portion 462 are provided in each of the two spaces divided by the second positioning portion 45 within the housing space 41a.

[0072] Each of the first conductor forming portion 461 and the second conductor forming portion 462 has a grounding portion 47. In other words, the cover member 40 has two grounding portions 47. Each of the grounding portions 47 extends from each of the first conductor forming portion 461 and the second conductor forming portion 462 and extends outward from the housing space 41a. In this embodiment, the grounding portion 47 is provided only on the conductor portion 46 of one of the two cover members 40. The grounding portion 47 is connected to the substrate 14. More specifically, the grounding portion 47 is connected to the substrate 14 so as to be connected to the ground potential of the power conversion unit 11. Therefore, the conductor portion 46 is connected to the ground potential of the power conversion unit 11. Note that in Figure 3, the part where the grounding portion 47 and the substrate 14 are connected is not shown.

[0073] <Relationship between the coil body and the cover component> In the common mode choke coil 30, the coil body 301 is housed by two cover members 40. In the common mode choke coil 30, the two cover members 40 are connected so as to house the coil body 301 in the housing space 41a, with the second ends of the peripheral walls 42 facing each other. The cover members 40 face the coil body 301 as will be described below.

[0074] The coil body portion 301 has two core case end faces 323 facing the end walls 43 of the cover member 40. In other words, the two cover members 40 are connected such that the axial direction of the peripheral wall 42 coincides with the direction in which the two core case end faces 323 are aligned, with the coil body portion 301 interposed between the end walls 43 of the two cover members 40.

[0075] The two cover members 40 are connected by bringing the second ends of their respective peripheral walls 42 into contact with each other. Furthermore, the two cover members 40 bring the conductive portions 46 provided at their respective second ends into contact with each other. In other words, the conductive portions 46 provided on each cover member 40 are electrically connected by the contact of their respective conductive portions 46 at their second ends. Therefore, the conductive portions 46 of a cover member 40 without a ground portion 47 are at the same potential as the ground portion 47. More specifically, the two cover members 40 electrically connect their first conductor forming portions 461 and their second conductor forming portions 462.

[0076] In this embodiment, the grounding portion 47 is provided on only one of the two cover members 40. The two cover members 40 house the coil body 301 in the housing space 41a, with the grounding portion 47 provided on one of the cover members 40 exposed from the housing space 41a.

[0077] The coil body 301 is housed in the housing space 41a with the first winding L1 and the second winding L2 facing the conductor portion 46. In other words, the conductor portion 46 faces the first winding L1 and the second winding L2. To put it another way, the conductor portion 46 is provided in the portion of the cover member 40 that faces the first winding L1 and the second winding L2. More specifically, the first winding L1 faces the first conductor forming portion 461 in the housing space 41a, and the second winding L2 faces the second conductor forming portion 462 in the housing space 41a. In other words, the first conductor forming portion 461 faces the first winding L1. The second conductor forming portion 462 faces the second winding L2 and is arranged at a distance from the first conductor forming portion 461.

[0078] The coil body 301 is housed in the cover member 40, with both ends of the first winding L1 and the second winding L2 protruding from two slits 44. Of the two slits 44, both ends of the first winding L1 protrude from one slit 44, and both ends of the second winding L2 protrude from the other slit 44.

[0079] In the housing space 41a, the coil body 301 has its bulging portions 331 in contact with each of the protrusions 45a of the cover member 40. In other words, the pair of protrusions 45a are in contact with the bulging portions 331 in the radial direction of the annular core 31. That is, the core case 32 has the pair of bulging portions 331 fitted into the recesses 45c inside the protrusions 45a. More specifically, the core case 32 is held by the cover member 40 by the fitting of the pair of bulging portions 331 into the recesses 45c formed by the protrusions 45a. In this way, the core case 32 is held by the cover member 40 by the fitting of the second positioning portion 45 into the first positioning portion 36.

[0080] Furthermore, the portion of the pair of bulging portions 331 facing the end wall 43 is inserted into the groove 45b. In this way, the movement of the core case 32 within the housing space 41a is restricted by the protruding portion 45a and the groove 45b. As described above, the movement of the coil body portion 301 within the cover member 40 is restricted by the first positioning portion 36 and the second positioning portion 45. In other words, the second positioning portion 45 works in cooperation with the first positioning portion 36 to position the first winding L1 and the second winding L2 relative to the conductor portion 46 within the cover member 40.

[0081] The cover member 40 holds the coil body 301 while separating the first winding L1 and the second winding L2 from the conductor portion 46 by the protruding portion 45a and the bulging portion 331. As a result, a gap 40a is formed between the first winding L1 and the second winding L2 and the conductor portion 46. In other words, the gap 40a is formed between the coil body 301 and the conductor portion 46 by the first positioning portion 36 and the second positioning portion 45. The second positioning portion 45 maintains the gap 40a formed between the coil body 301 and the conductor portion 46.

[0082] In Figure 2, the capacitance in the gap 40a between the first winding L1 and the second winding L2 and the conductor portion 46 is represented as a capacitor CC having said capacitance. Capacitor CC is grounded by the ground portion 47 of the conductor portion 46 shown in Figure 3.

[0083] The first positioning section 36 and the second positioning section 45 restrict the movement of the coil body section 301 inside the cover member 40, thereby suppressing changes in the size of the gap 40a that occur with such movement. In this specification, the size of the gap 40a refers to the size of the distance between the first winding L1 and the second winding L2 and the conductor section 46.

[0084] The size of the gap 40a is set according to the parasitic capacitance of the first winding L1 and the second winding L2, respectively. The size of the gap 40a is preferably set so that the capacitance generated by the conductor portion 46 and the first and second windings L1 and L2 cancels out the parasitic capacitance. More specifically, the gap 40a is preferably set so that the capacitance generated by the conductor portion 46 and the first and second windings L1 and L2 is between 3 and 10 times the parasitic capacitance of the first and second windings L1 and L2, respectively. In this embodiment, the gap 40a is set so that the capacitance generated by the conductor portion 46 and the first and second windings L1 and L2 is 4 times the parasitic capacitance of the first and second windings L1 and L2, respectively.

[0085] <Function of the noise filter section> The in-vehicle power supply unit 10 converts the power input to the power conversion unit 11 by operating a plurality of switching elements (not shown) in the power conversion unit 11 via the control device 13. The switching operation during this conversion generates conducted noise in the power conversion unit 11. The generated conducted noise flows out from the power conversion unit 11 towards the input / output unit 12 via the first wiring EL1 and the second wiring EL2.

[0086] Conducted noise flowing out from the power conversion unit 11 flows into the noise filter unit 20 before reaching the input / output unit 12. More specifically, the conducted noise flows into the first noise filter unit 20 before reaching the input terminal 12a, and into the second noise filter unit 20 before reaching the output terminal 12b.

[0087] Conducted noise flowing into the noise filter section 20 is reduced by the X capacitor 21, the pair of Y capacitors 22, and the common-mode choke coil 30. In other words, the noise filter section 20 reduces the common-mode noise contained in the power going from the power conversion section 11 to the input / output section 12. As a result, the noise filter section 20 suppresses the outflow of conducted noise generated in the power conversion section 11 to the outside of the onboard power supply unit 10 via the input / output section 12.

[0088] In the noise filter section 20, the influence of the parasitic capacitance of the virtual capacitor CP on the noise reduction performance of the noise filter section 20 is reduced by the capacitance of capacitor CC. By setting the gap 40a so that the capacitance of capacitor CC is between 3 and 10 times the parasitic capacitance of the virtual capacitor CP, the parasitic capacitance in the noise filter section 20 is reduced even further than when it is not set as described above.

[0089] [Operation of this embodiment] The operation of this embodiment will now be explained. The gap 40a is maintained by the first positioning section 36 and the second positioning section 45. The size of the gap 40a can be adjusted, for example, only by adjusting the radial dimensions of the cover member 40. In this way, the first positioning section 36 and the second positioning section 45 facilitate the adjustment of the capacitance between the first winding L1 and the second winding L2 and the conductor section 46.

[0090] [Effects of this embodiment] The effects of this embodiment will now be explained. (1) In the noise filter section 20, the common mode choke coil 30 generates capacitance through the first winding L1 and the second winding L2 of the coil body section 301 and the conductor section 46 of the cover member 40. This capacitance reduces the parasitic capacitance generated by the first winding L1 and the second winding L2, respectively, in the common mode choke coil 30.

[0091] Furthermore, the coil body 301 is positioned relative to the cover member 40 through the cooperation of the first positioning unit 36 ​​and the second positioning unit 45. In other words, the gap 40a between the first winding L1 and the second winding L2 and the conductor unit 46 is maintained at a constant size by the first positioning unit 36 ​​and the second positioning unit 45. As a result, the size of the gap 40a can be adjusted, for example, by changing the dimensions of the cover member 40. In other words, the size of the gap 40a is easier to adjust compared to, for example, a case where the first positioning unit 36 ​​is not provided on the core case 32 and the second positioning unit 45 is not provided on the cover member 40. Since the capacitance generated by the first winding L1 and the second winding L2 and the conductor unit 46 is adjusted by the size of the gap 40a, the on-board power supply unit 10 can easily adjust the capacitance.

[0092] (2) In the conductor portion 46, the first conductor forming portion 461 and the second conductor forming portion 462 are arranged with a gap between them. The area of ​​the conductor portion 46 can be reduced compared to, for example, the case in which it is provided over the entire portion of the cover member 40 facing the coil body portion 301. Furthermore, even if the shape of the portion of the cover member 40 that becomes the second positioning portion 45 is complex, the conductor portion 46 can be provided only in the portion facing the first winding L1 and the second winding L2, excluding that portion. As a result, in the on-board power supply device 10, the conductor portion 46 can be easily provided on the cover member 40 compared to the case in which the conductor portion 46 does not have the first conductor forming portion 461 and the second conductor forming portion 462.

[0093] (3) In the conductor portion 46, the first conductor forming portion 461 and the second conductor forming portion 462 are arranged with a gap between them. In the on-board power supply unit 10, for example, the creepage distance between the first winding L1 and the second winding L2 can be increased compared to the case where the conductor portion 46 is provided over the entire portion of the cover member 40 that faces the first winding L1 and the second winding L2.

[0094] (4) By forming the cover member 40 with a separate main body 41 and conductor 46, the on-board power supply unit 10 can reduce manufacturing costs compared to, for example, a case where the cover member 40 is made of a metal material with the conductor 46 being a part of it.

[0095] (5) The cover member 40 is formed from a separate main body 41 and a conductor 46. For example, if the cover member 40 and the conductor 46 are made of a metal material that is integrally molded, the entire portion of the cover member 40 that faces the first winding L1 and the second winding L2 becomes a conductor. In other words, in the on-board power supply unit 10, for example, the creepage distance between the first winding L1 and the second winding L2 can be increased compared to the case where the cover member 40 is made of a metal material in which the main body 41 and the conductor 46 are integrally molded.

[0096] (6) The on-board power supply unit 10 can use the bulging portion 331, which is part of the partition portion 33 provided in the core case 32 to ensure the creepage distance between the first winding L1 and the second winding L2, as the first positioning portion 36. As a result, by using a core case 32 in which the partition portion 33 is provided in advance to ensure the creepage distance, the on-board power supply unit 10 can position the coil body portion 301 relative to the cover member 40 without having to perform any further processing on the core case 32.

[0097] (7) The on-board power supply unit 10 can miniaturize the common mode choke coil 30 compared to the case where, for example, the first winding L1 and the second winding L2 form a less dense portion in the first winding section 34 and the second winding section 35, respectively. Furthermore, the on-board power supply unit 10 can reduce the leakage flux caused by that portion.

[0098] (8) The capacitance generated by the first winding L1 and the second winding L2 and the conductor portion 46 is set to be between 3 and 10 times the parasitic capacitance in each of the first winding L1 and the second winding L2. The parasitic capacitance in the common mode choke coil 30 is reduced compared to when the capacitance is not set as described above. In other words, the on-board power supply unit 10 can reduce the parasitic capacitance in the common mode choke coil 30.

[0099] [Example of changes] The above embodiment can be implemented with the following modifications. The above embodiment and the following modifications can be combined with each other to the extent that they do not contradict each other technically.

[0100] ○ As shown in Figure 5, the noise filter section 20 may have a dielectric 60 placed in the gap 40a. In this case, a sheet of resin is inserted as the dielectric 60 between the first winding L1 and the second winding L2 and the conductor section 46. Examples of resins include epoxy resin.

[0101] In this case, the capacitance generated by the first winding L1, the second winding L2, and the conductor portion 46 can be adjusted not only by the distance between each of the first winding L1 and the second winding L2 and the conductor portion 46, but also by the dielectric constant of the dielectric 60.

[0102] ○ The gap 40a does not need to be set such that the capacitance generated by the conductor portion 46 and the first winding L1 and the second winding L2 is between 3 and 10 times the parasitic capacitance in each of the first winding L1 and the second winding L2. In short, the gap 40a just needs to be set such that the capacitance generated by the conductor portion 46 and the first winding L1 and the second winding L2 is a value that can reduce the parasitic capacitance in the common mode choke coil 30.

[0103] ○ The first winding L1 does not have to be tightly wound around the core case 32. Similarly, the second winding L2 does not have to be tightly wound around the core case 32. In other words, the first winding L1 may be wound around the core case 32 on the inner surface 321 of the core case with spacing between it in the circumferential direction. Similarly, the second winding L2 may be wound around the core case 32 on the inner surface 321 of the core case with spacing between it in the circumferential direction.

[0104] ○ The bulge 331 does not have to be included in the partition 33. In other words, the bulge 331 does not have to be configured to partition the first winding L1 and the second winding L2 in the circumferential direction of the annular core 31. For example, the bulge 331 may be formed in the first winding section 34 and the second winding section 35. In this case, the first winding L1 and the second winding L2 are wound around the first winding section 34 and the second winding section 35, respectively, while avoiding the bulge 331.

[0105] ○ The first positioning portion 36 does not necessarily have a pair of bulging portions 331. Also, the second positioning portion 45 does not necessarily have a protruding portion 45a that contacts the pair of bulging portions 331.

[0106] For example, as shown in Figure 6, the first positioning portion 36 may be four portions formed on the outer peripheral surface 322 of the core case at equal intervals in the circumferential direction of the core case 32, where the first winding L1 and the second winding L2 are not wound. In this case, the second positioning portion 45 has four protrusions 45a that protrude from the inner peripheral surface of the peripheral wall 42, and each protrusion 45a abuts against the opposing first positioning portion 36. In other words, in the case shown in Figure 6, the cover member 40 holds the core case 32 by only bringing the four protrusions 45a into contact with the first positioning portion 36 provided on the portions where each protrusion 45a faces. They are not fitted together individually, but the four contacts work together to hold the core case 32.

[0107] The first positioning portion 36 and the second positioning portion 45 in the above configuration can be held and positioned relative to the cover member 40 even if the core case 32 does not have a pair of bulging portions 331 formed thereon.

[0108] ○ The main body 41 may be made of metal. Also, the conductor 46 does not have to be foil-like. For example, the main body 41 and the conductor 46 may be integrated to form the cover member 40. In this case, the work of attaching the foil-like conductor 46 to the main body 41 is omitted, thus simplifying the manufacturing of the cover member 40.

[0109] ○ The conductor portion 46 may be a single piece that is not divided into a first conductor forming portion 461 and a second conductor forming portion 462. In this case, the conductor portion 46 may be formed on the entire surface of the peripheral wall 42 and end wall 43 that surrounds the housing space 41a, and may also be formed on the second positioning portion 45. In this case, one grounding portion 47 is sufficient for the conductor portion 46.

[0110] ○ The conductor portion 46 may be divided into three or more conductor forming portions. In this case, a grounding portion 47 is provided for each conductor forming portion. ○ The conductor portion 46 does not have to be provided on both of the two cover members 40. For example, the conductor portion 46 may be provided on only one of the two cover members 40. In short, the cover member 40 should generate a capacitance between the first winding L1 and the second winding L2 and the conductor portion 46 in the common mode choke coil 30 that is large enough to reduce the parasitic capacitance caused by each of the first winding L1 and the second winding L2.

[0111] ○ The on-board power supply unit 10 may have only one cover member 40. In this case, the coil body 301 is housed in the housing space 41a of the single cover member 40. ○ The shape and function of the cover member 40 are not limited to the embodiment. For example, as shown in Figure 7, when the on-board power supply unit 10 has a housing 101, the housing 101 houses the power conversion unit 11 and the noise filter unit 20 shown in Figure 1. The on-board power supply unit 10 may use a part of the housing 101 of the on-board power supply unit 10 as the cover member 40. In other words, the cover member 40 may constitute a part of the housing 101. In this case, the conductor portion 46 is provided in the part of the housing 101 that faces the first winding L1 and the second winding L2. Although not shown, the conductor portion 46 is grounded to the power conversion unit 11 mounted on the substrate 14. Note that in Figure 7, only the first winding L1 is shown, and the second winding L2 is not shown. In Figure 7, the second winding L2 is aligned with the first winding L1 in a direction perpendicular to the plane of the paper.

[0112] The coil body 301 has a pair of bulging portions 331 that constitute the first positioning portion 36 in contact with the portion of the housing 101 that faces the bulging portions 331. As a result, the first winding L1 and the second winding L2 are positioned within the housing 101 relative to the conductor portion 46. In this case, the second positioning portion 45 is the portion of the housing 101 in contact with the pair of bulging portions 331.

[0113] According to this, by providing the conductor portion 46 in the housing 101 of the on-board power supply unit 10, it is not necessary to add any separate parts to the on-board power supply unit 10 to provide the conductor portion 46. As a result, the on-board power supply unit 10 can generate capacitance to reduce the parasitic capacitance in the common mode choke coil 30 in accordance with the parasitic capacitance of the first winding L1 and the second winding L2, while suppressing an increase in the number of parts.

[0114] ○ The on-board power supply unit 10 does not have to have two noise filter units 20. The on-board power supply unit 10 may have only one noise filter unit 20. More specifically, the on-board power supply unit 10 may have only one of the first noise filter unit 20 and the second noise filter unit 20.

[0115] ○ The on-board power supply unit 10 may have three or more noise filter units 20. ○ The on-board power supply unit 10 is not limited to an on-board charging device. For example, the on-board power supply unit 10 may be used as a DC / DC converter or an AC inverter. In these cases, the configuration and function of the power conversion unit 11 are appropriately changed depending on the application of the on-board power supply unit 10. For example, if the on-board power supply unit 10 is a DC / DC converter, the power conversion unit 11 functions as a DC / DC converter. The noise filter unit 20 reduces conducted noise generated by the power conversion by the DC / DC converter before it reaches the input / output unit 12. [Explanation of Symbols]

[0116] 10...Vehicle power supply unit, 11...Power conversion unit, 12...Input / output unit, 20...Noise filter unit, 30...Common mode choke coil, 31...Annular core, 32...Core case, 33...Partition unit, 34...First winding unit, 35...Second winding unit, 36...First positioning unit, 40...Cover member, 40a...Gap, 41...Main body unit, 45...Second positioning unit, 45a...Protruding part, 45c...Recessed part, 46...Conductor unit, 60...Dielectric, 101...Housing, 301...Coil main body unit, 331...Bulging part, 461...First conductor forming unit, 462...Second conductor forming unit, L1...First winding, L2...Second winding.

Claims

1. A power conversion unit that converts the input power, An input / output unit that receives the power converted by the power conversion unit and outputs the power converted by the power conversion unit, The power conversion unit and the input / output unit are electrically connected, and the noise filter unit is equipped with a common mode choke coil, The common mode choke coil is A coil body having an annular core, a core case housing the annular core, a first winding wound around the core case, and a second winding wound around the core case at a distance from the first winding, It has a cover member facing the coil body, The core case has a first positioning portion, The cover member is A conductor portion that faces the first winding and the second winding and is connected to the ground potential of the power conversion unit, An on-board power supply device having a second positioning unit that cooperates with the first positioning unit to position the first winding and the second winding relative to the conductor portion inside the cover member, and maintains the gap formed between the first winding and the second winding and the conductor portion.

2. The aforementioned conductor portion is A first conductor forming portion facing the first winding, The vehicle power supply device according to claim 1, further comprising: a second conductor forming portion that faces the second winding and is spaced apart from the first conductor forming portion.

3. The cover member has a main body made of resin material on which the second positioning portion is provided, The in-vehicle power supply device according to claim 1 or claim 2, wherein the conductor portion is a foil-like body provided in the portion of the main body facing the first winding and the second winding.

4. The first positioning portion has a pair of bulges that bulge radially in the annular core on the outer surface of the core case, wherein one bulge is provided on the part of the core case opposite to the other bulge. The second positioning portion has protrusions that abut against a pair of bulging portions in the radial direction of the annular core, The in-vehicle power supply device according to claim 1 or claim 2, wherein the core case is held by the cover member by a pair of bulging portions fitting into recesses formed by the protruding portions.

5. The in-vehicle power supply device according to claim 4, wherein the bulging portion is included in a partition portion that separates the first winding and the second winding in the circumferential direction of the annular core.

6. The aforementioned core case is The first winding section in which the first winding is tightly wound, An in-vehicle power supply device according to claim 1 or claim 2, comprising a second winding section in which the second winding is tightly wound.

7. The vehicle power supply device according to claim 1 or 2, wherein the gap is set such that the capacitance generated by the conductor portion and the first winding and the second winding is 3 times or more and 10 times or less the parasitic capacitance of the first winding and the second winding, respectively.

8. The on-board power supply device according to claim 1 or claim 2, wherein the noise filter section has a dielectric material arranged in the gap.

9. The housing comprises the power conversion unit and the noise filter unit, The in-vehicle power supply device according to claim 1 or claim 2, wherein the cover member constitutes a part of the housing.

Images