Electrical device

Abstract

Provided is an electrical device comprising a plurality of bus bars, a current sensor section that detects currents flowing through the plurality of bus bars, and a housing that accommodates therein the plurality of bus bars and the current sensor. The current sensor section has a plurality of magnetic cores which each have an air gap and which surround the periphery of the plurality of bus bars, a magnetic detection element which is disposed in the air gaps, and a circuit board to which the magnetic detection element is mounted. The housing is composed of a non-magnetic material and has a plurality of accommodation sections which are in communication with the inside of the housing and the outside of the housing, and into which the plurality of magnetic cores are respectively fitted by insertion.

Description

Electrical device

[0001] The present invention relates to an electrical device.

[0002] The following Patent Document 1 discloses an inverter device in which a magnetic core and an IC circuit are housed in a molded case.

[0003] Japanese Unexamined Patent Application Publication No. 2024-005487

[0004] In view of the configuration described in Patent Document 1, an object of the present invention is to provide an electrical device that achieves miniaturization and cost reduction.

[0005] An electrical device comprising: a plurality of bus bars, a current sensor unit that detects current flowing through the plurality of bus bars, and a housing that accommodates the plurality of bus bars and the current sensor unit inside, wherein the current sensor unit includes a plurality of magnetic cores each having an air gap and respectively surrounding the periphery of the plurality of bus bars, a magnetic detection element arranged in the air gap, and a circuit board on which the magnetic detection element is mounted, the housing is made of a non-magnetic material, and has a plurality of accommodating portions that communicate the inside of the housing with the outside of the housing and into which the plurality of magnetic cores are respectively inserted and fitted.

[0006] The electrical device that achieves miniaturization and cost reduction can be provided.

[0007] A cross-sectional view illustrating the internal configuration of the housing of the electrical device according to the first embodiment of the present invention. An A-A cross-sectional view of Figure 1. A cross-sectional view illustrating the process of fixing the magnetic core with the snap ring portion attached to the housing according to the first embodiment of the present invention. A cross-sectional view illustrating the internal configuration of the housing according to the second embodiment of the present invention. A B-B cross-sectional view of Figure 4. A cross-sectional view illustrating a modification of the second embodiment of the present invention. A cross-sectional view illustrating the internal configuration of the housing according to the third embodiment of the present invention. A C-C cross-sectional view of Figure 7.

[0008] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following description and drawings are examples for explaining the present invention, and are appropriately omitted and simplified for clarity of explanation. The present invention can be implemented in various other forms. Unless otherwise particularly limited, each constituent element may be singular or plural.

[0009] The positions, sizes, shapes, and ranges of the components shown in the drawings may not represent their actual positions, sizes, shapes, and ranges in order to facilitate understanding of the invention. Therefore, the present invention is not necessarily limited to the positions, sizes, shapes, and ranges disclosed in the drawings.

[0010] (First Embodiment and Overall Configuration) (Figures 1 to 3) The housing 100 is a housing for an inverter device mounted on, for example, a vehicle, and is a structure for housing a power module 110, which is a switch module of the inverter device. The housing 100 is made of a non-magnetic material (for example, aluminum). The housing 100 is equipped with a plurality of busbars, of which the DC busbar 113 is electrically connected to the capacitor 112 and the power module 110, and the busbar 105 is connected to the power module 110. The busbar 105 is, for example, an AC busbar and is electrically connected to a motor (not shown) installed outside the housing 100.

[0011] The current flowing through the busbar 105 is detected by a current sensor unit 120 (Figure 2(a)) provided inside the housing 100. The current sensor unit 120 has an air gap portion 107a (Figure 2(b)) and comprises a plurality of magnetic cores 107 formed to surround each of the plurality of busbars 105, a magnetic detection element 103 placed in the air gap portion 107a, and a current sensor board 102 which is a circuit board on which the magnetic detection element 103 is mounted.

[0012] Furthermore, the housing 100 has a plurality of housing sections 106 that connect the inside of the housing 100 to the outside of the housing 100, and into which a plurality of magnetic cores 107 are fitted (fitted and inserted). The housing sections 106 are shaped to accommodate the magnetic cores 107 in the housing 100. As shown in Figure 3(b), the plurality of magnetic cores 107 are fixed to the housing 100 as shown in Figure 3(a) by being inserted into each housing section 106. With the magnetic cores 107 fixed to the housing 100, the positions of the magnetic cores 107 and the air gap section 107a are maintained at predetermined positions in the housing 100.

[0013] The magnetic detection element 103 is inserted into the air gap portion 107a of the magnetic core 107, detects the strength of the magnetic flux generated from the busbar 105, converts it into a voltage value, and feeds that voltage value back to the control board 117. The magnetic detection element 103 is mounted on the current sensor board 102, but it may also be integrated with the current sensor board 102 or another board such as the driver board 114.

[0014] The insulator 104 is formed to surround the busbar 105 and the DC busbar 113, respectively. With this configuration, the housing 100 and the magnetic core 107 are insulated from the busbar 105 and the DC busbar 113. When current flows through the busbar 105, a magnetic flux is generated around the busbar 105, but this magnetic flux is collected by the magnetic core 107 and concentrated in the air gap portion 107a. As a result, the magnetic detection element 103 detects the strength of the generated magnetic flux.

[0015] As shown in Figure 3, the magnetic core 107 is a laminated core stacked according to the insertion direction 105a of the busbar 105. The magnetic core 107 is made of a magnetic material, for example, silicon steel sheet, which makes it easy to design its shape. The magnetic core 107 also has a snap ring portion 108. The housing portion 106 has a groove portion 109 formed therein for fixing the snap ring portion 108. The snap ring portion 108 is provided at the end of the surface facing the contact surface 107b that abuts the housing portion 106 in the stacking direction of the magnetic core 107. The snap ring portion 108 is made of stainless steel spring steel. The snap ring portion 108 is fitted together with the magnetic core 107 from the inside of the housing 100 toward the housing portion 106 and is fitted into the groove portion 109, thereby fixing the magnetic core 107 to the housing portion 106.

[0016] This configuration reduces the space required for mounting the magnetic core 107 within the housing 100 compared to conventional designs, contributing to a smaller inverter device housing 100, a reduction in the number of parts, and a shorter installation time. Furthermore, because the magnetic core 107 is directly fixed to the housing 100, it is grounded via the housing 100, allowing the effects of voltage fluctuations caused by the current supplied from the busbar 105 to be dissipated to the housing 100. This reduces noise generation and malfunctions when the magnetic detection element 103 detects the current from the busbar 105. In addition, the heat generated by the magnetic core 107 can be directly dissipated to the housing 100.

[0017] A cooling water channel 111 located inside the housing 100 cools the heat-generating power module 110. The capacitor 112 is a capacitor that constitutes the inverter device. The DC busbar 113 carries a DC current supplied from the main power supply and is connected to the capacitor 112. The electrical connection connector section 101 electrically connects the current sensor board 102 and the control board 117 inside the housing 100, transmitting signals between the boards. The control board 117 sends a command signal to the driver board 114 based on the feedback signal received from the current sensor board 102. The driver board 114 controls the operation of the power module 110 based on the command signal from the control board 117. The board fixing screws 116 fix the control board 117 and the driver board 114 to the board fixing frame 115.

[0018] Furthermore, the snap ring portion 108 is secured to the magnetic core 107 at at least three points when attached to the magnetic core 107 to ensure attachment stability. Also, the magnetic core 107 may be of a coiled shape as well as a laminated shape, as long as it can be accommodated in the housing portion 106. In addition, although the snap ring portion 108 has been described as being separate from the magnetic core 107 and attached to the magnetic core 107, for example, in a laminated magnetic core 107, the snap ring structure may be laminated on the last laminated portion on the side opposite to the contact surface 107b, thereby integrating it with the magnetic core 107.

[0019] The effects of the embodiments of the present invention will now be explained in comparison with conventional configurations. In conventional inverter devices, for example, if a current sensor unit is formed by combining a core mold, which has a magnetic core fixed to a mold, and a current sensor substrate, and then assembled into the housing of the inverter device, it is necessary to maintain the positional relationship between the magnetic core and the current sensor substrate with the mold, and therefore it is necessary to secure space inside the housing to assemble the current sensor unit. Furthermore, even in a magnetic core mounting configuration that does not require a mold, the magnetic core needs to be insulated from the housing. Taking these issues into account, in the embodiments of the present invention, it is not necessary to assemble the current sensor unit in advance, and it is only necessary to attach the magnetic core to the housing, thereby enabling miniaturization and cost reduction of the inverter device. In addition, since a molded case like in the conventional method is not required, there is no need to consider risks such as mounting strength.

[0020] (Second Embodiment) (Figures 4 and 5) The housing section 106 may be provided on the bottom surface of the housing 100, rather than on the side surface of the housing 100, as shown in Figures 1 and 2. In this configuration, the busbar 105 is arranged in a direction intersecting the bottom surface of the housing 100 and extends from the bottom surface of the housing 100 to the outside of the housing 100. The magnetic core 107 is fitted toward the bottom surface of the housing 100. The busbar 105 passes through the central hole of the magnetic core 107 and extends toward the bottom surface of the housing 100. This configuration can be applied when a motor (not shown) is provided on the bottom surface of the housing 100, and a structure can be realized in which the busbar 105 is directed toward the bottom surface of the housing 100 and outputs alternating current. Furthermore, in the process of mounting the components into the housing 100, the mounting direction of the magnetic core 107 and the busbar 105 can be made common with the mounting direction of other mounted components inside the housing 100, thus shortening the component mounting process.

[0021] (Modified Version) (Figure 6) The magnetic core 107 may be inserted from the outside of the housing 100 and fixed to the housing 100. The housing portion 106 has an opening facing outwards from the housing 100, allowing the magnetic core 107 to be easily inserted from the outside of the housing 100 and fixed to the housing 100. With this configuration, it is not necessary to attach the magnetic core 107 to the housing 100 before the process of housing the substrate and busbar components inside the housing 100. Also, since the state in which the magnetic core 107 is attached to the housing 100 can be confirmed from the outside of the housing 100, it becomes easy to confirm the position of the air gap portion 107a (Figure 2) after the magnetic core 107 has been attached, and to confirm whether or not the magnetic core 107 has been attached. In addition, since the housing portion 106 is provided on the outside of the housing 100, the possibility of metal contaminants entering the inside of the housing 100 when the magnetic core 107 is attached can be reduced.

[0022] (Third Embodiment) (Figures 7 and 8) The housing portion 106 for the magnetic core 107 may be provided on the substrate fixing frame 115. In this embodiment, even if the housing portion 106 is provided so that the busbar 105 is inserted in the planar direction in the inverter device, the busbar 105 can be bent into an L shape. This allows the busbar 105 to be electrically connected to the motor, for example, when the motor is provided on the lower side of the housing 100. In addition, since the magnetic core 107 is fixed to the substrate fixing frame 115, it can be grounded via the substrate fixing frame 115 and the housing 100, thus reducing the influence of noise.

[0023] It should be noted that the present invention is not limited to the embodiments described above, and various modifications and combinations of other configurations can be made without departing from the spirit of the invention. Furthermore, the present invention is not limited to having all the configurations described in the embodiments described above, and may also include configurations in which some of those configurations are omitted.

[0024] 100 Housing 101 Electrical connector 102 Current sensor board 103 Magnetic detection element 104 Insulator 105 Busbar 105a Busbar insertion direction 106 Housing section 107 Magnetic core 107a Air gap section 107b Contact surface with housing section 108 Snap ring section 109 Groove section 110 Power module 111 Cooling water channel 112 Capacitor 113 DC busbar 114 Driver board 115 Board fixing frame 116 Board fixing screws 117 Control board 120 Current sensor section

Claims

1. An electrical device comprising: a plurality of busbars; a current sensor unit for detecting current flowing through the plurality of busbars; and a housing for housing the plurality of busbars and the current sensor unit, wherein the current sensor unit comprises a plurality of magnetic cores having an air gap and surrounding each of the plurality of busbars, a magnetic detection element disposed in the air gap, and a circuit board on which the magnetic detection element is mounted, and the housing is made of a non-magnetic material and has a plurality of housings that communicate the inside of the housing with the outside of the housing and into which each of the plurality of magnetic cores is fitted.

2. The electrical device according to claim 1, wherein the magnetic core is fixed to the housing and grounded.

3. The electrical device according to claim 1, wherein the magnetic core is formed by stacking according to the insertion direction of the busbar.

4. The electrical device according to claim 1, wherein the magnetic core has a snap ring portion, the housing portion has a groove portion for fixing the snap ring portion, and the snap ring portion is provided on a surface of the magnetic core opposite to the surface that contacts the housing portion, and is fixed to the groove portion.

5. The electrical device according to claim 1, wherein the housing is provided on the bottom surface of the housing, and the busbar is arranged in a direction intersecting the bottom surface of the housing.

6. The electrical device according to claim 1, wherein the magnetic core is inserted from the outside of the housing and fixed to the housing.

Images