VOLTAGE CONVERSION DEVICE AND MANUFACTURING METHOD

A voltage conversion device includes: a board on which an electronic component having a power conversion function is mounted; and a capacitor unit detachably attached to the board and electrically connected to the board. The capacitor unit includes: a capacitor; a capacitor board on which the capacitor is mounted; and resin by which the capacitor and the capacitor board are enclosed

TECHNICAL FIELD

The present invention relates to a voltage conversion device and a manufacturing method.

BACKGROUND ART

In the related arts, there is a voltage conversion device that converts a DC input voltage into a predetermined voltage. For example, one of the voltage conversion devices of the related arts is mounted on a vehicle such as an electric vehicle (EV), and uses an electronic component (such as a transformer) having a power conversion function to step up (or step down) the voltage to a predetermined voltage according to the control of the vehicle and charge a storage battery or the like (for example, refer to Patent Literature 1).

CITATION LIST

Patent Literature

SUMMARY OF INVENTION

Technical Problem

In general, in a voltage conversion device, noise is generated in the current due to the influence of switching and the like during transformation, and thus it is necessary to remove the noise generated in the current. Many voltage conversion devices in the related arts cope with the above noise by mounting a capacitor having a noise filter function on a board including a transformer or the like.

Incidentally, the voltage conversion device described above may be accelerated due to the influence of the vehicle in which the voltage conversion device is mounted. Here, the capacitor mounted on the board is greatly affected by acceleration due to the shape of the capacitor itself, and there is a concern that the capacitor is detached from the board. To cope with the detachment of the capacitor from the board as described above, there is a method of holding down a lower end portion of the capacitor using synthetic resin such as plastic as a base. However, in the above method, the base is expensive, and thus there is a concern that the manufacturing cost will increase.

In voltage conversion devices of the related arts, the board including the capacitor is often housed inside a housing, and thus replacement of the capacitor with respect to the board is not taken into consideration. On the other hand, in consideration of the failure of the capacitor due to the influence of heat or the deterioration of the capacitor over time due to power reception at a high temperature, more capacitors than necessary were mounted on the board. As a result, the number of capacitors in the voltage conversion device increases, further increasing the manufacturing cost.

The voltage conversion device and the manufacturing method according to the embodiments can reduce the manufacturing cost.

Solution to Problem

According to an embodiment, there is provided a voltage conversion device including:a board on which an electronic component having a power conversion function is mounted; anda capacitor unit detachably attached to the board and electrically connected to the board, in whichthe capacitor unit includesa capacitor,a capacitor board on which the capacitor is mounted, andresin by which the capacitor and the capacitor board are enclosed.

According to another embodiment, there is provided a method for manufacturing the voltage conversion device, the method including:a selection step of selecting one or a plurality of the capacitor units from among a plurality of capacitor units including different types of capacitors; anda mounting step of mounting the capacitor unit selected in the selection step on the board.

Advantageous Effects of Invention

According to the voltage conversion device according to one embodiment, the capacitor unit is detachably attached to the board on which the electronic component having the power conversion function is mounted. As a result, even when a failure in the capacitor due to the influence of heat or deterioration of the capacitor over time due to power reception at a high temperature occurs, the capacitor unit can be removed from the board and replaced. In other words, since the capacitor unit can be replaced with respect to the board, there is no need to mount more capacitors than necessary on the capacitor board. As a result, the voltage conversion device having such configuration includes a smaller number of capacitors compared to the voltage conversion device of the related arts.

According to the voltage conversion device configured as described above, even when the voltage conversion device is accelerated, for example, the capacitor and the capacitor board are enclosed by the resin, and thus the capacitor is prevented from being detached from the capacitor board. Accordingly, there is no need to provide an expensive base unlike the voltage conversion device of the related arts.

As described above, the manufacturing cost of the voltage conversion device configured as described above is reduced compared to the voltage conversion device of the related arts.

Note that the capacitor unit in the voltage conversion device configured as described above is assumed as a noise filter having a function of removing noise generated during voltage conversion, but is not limited thereto. The manufacturing method according to the embodiment can obtain the above-described effects of the voltage conversion device.

DESCRIPTION OF EMBODIMENTS

Embodiment

A voltage conversion device1according to an embodiment of the present invention will be described below with reference to the drawings. The voltage conversion device1is mounted in a vehicle, that is, an automobile such as an electric vehicle or a connected car having a function as an information and communication technology (ICT) terminal.

As shown inFIG.1, the voltage conversion device1includes a capacitor unit10, a board20to which the capacitor unit10is detachably attached, and a case30that houses the capacitor unit10and the board20. Hereinafter, the capacitor unit10, the board20, and the case that configure the voltage conversion device1will be described in order.

First, the capacitor unit10will be described. As shown inFIGS.1and2, the capacitor unit10includes a capacitor11, a capacitor board12on which the capacitor11is mounted, resin13enclosing the capacitor11and the capacitor board12, and a cover14attached to the resin13enclosing the capacitor11and the capacitor board12.

Since the capacitor11is used as a noise filter that removes noise generated during voltage conversion by the voltage conversion device1, the capacitor11preferably has a large capacitance (that is, a low impedance). Therefore, as the capacitor11, for example, an aluminum electrolytic capacitor or the like is used.

As shown inFIG.3, the capacitor board12is provided with a potential area17electrically connected to a terminal portion18, which will be described later. The potential area17is, for example, a circuit pattern provided on the capacitor board12. The potential area17includes an anode area17aconnected to an electrode of a battery or the like and a ground area17bconnected to the ground. The capacitor board12is provided with the terminal portion18that is elastically and electrically connected to a spring terminal21of the board20, which will be described later.

The resin13is composed of solidified resin capable of enclosing the capacitor11and the capacitor board12. However, the resin13is not limited thereto as long as the capacitor11and the capacitor board12are enclosed.

The cover14is made of metal material. As shown inFIGS.2and3, the cover14has a substantially rectangular cylindrical shape having a bottom, of which a lower surface is open. A flange15extending toward an outside of the cover14is provided at a lower end portion of a side wall of the cover14.

The flange15is provided with screw holes16through which screws4are inserted when the capacitor unit10is mounted on the board20. In other words, the flange15functions as a fastening portion when the capacitor unit10is mounted on the board20.

Here, a method for manufacturing the capacitor unit10will be described. First, a plurality of capacitors11are mounted on the board20. Specifically, a pair of lead wires (not shown) of each capacitor11are electrically connected to the anode area17aand the ground area17bof the board20, respectively.

Next, the capacitor11and the capacitor board12are enclosed by the resin13. Specifically, the capacitor board12on which the capacitors11are mounted is housed in, for example, a container (not shown), the resin13is poured into the container, and the resin13is solidified by various methods. Here, the resin13is poured until the lower end portion of the capacitor11is buried. As a result, the capacitor11and the capacitor board12are enclosed by the resin13.

Next, the cover14is attached to the resin13in which the capacitor11and the capacitor board12are enclosed. Specifically, the resin13in which the capacitor11and the capacitor board12are enclosed is covered with the cover14from above. Thus, the capacitor unit10is obtained.

In the present embodiment, the cover14has a shape corresponding to the capacitor board12including the capacitor11and the resin13, and thus the capacitor board12is fitted in the opening part of the lower surface of the cover14.

However, the manner in which the cover14is attached to the resin13in which the capacitor11and the capacitor board12are enclosed is not limited thereto. The method for manufacturing the capacitor unit10is not limited to the above, and may be set as appropriate. The capacitor unit10has been described above.

Next, the board20will be described. The board20configures an electronic (electrical) circuit of the voltage conversion device1. The board20is configured by, for example, a printed circuit board (PCB) or the like.

In other words, the board20is formed by printing a wiring pattern (print pattern) with a conductive material such as copper on an insulating layer made of an insulating material such as epoxy resin, glass epoxy resin, paper epoxy resin, or ceramic, thereby forming a circuit body with the wiring pattern.

As shown inFIG.4, the board20includes the spring terminal21having a cantilever shape. The spring terminal21includes a board connection portion22electrically connected to the circuit pattern of the board20, a terminal connection portion23electrically connected to the terminal portion18of the capacitor unit10, and an intermediate portion24positioned between the board connection portion22and the terminal connection portion23, which are integrated with each other.

As shown inFIG.1, the board20is mounted with a transformer2, a heat sink3, and the like in addition to the capacitor unit10. The transformer2steps up or steps down an AC voltage converted from a DC power supply, for example, by controlling on/off of a switch in a switching element (not shown). The heat sink3has a function of dissipating and exhausting heat generated during transformation.

Various electronic components are mounted on the board20in addition to the transformer2and the heat sink3, but the description thereof will be omitted. Note that the transformer2corresponds to “an electronic component having a power conversion function”. The board20has been described above.

Next, the case30will be described. The case30is made of a metal material and houses the capacitor unit10and the board20. As shown inFIG.1, the case30includes a case main body31of which an upper surface is open and a case cover32assembled to the case main body31to cover the upper surface opening of the case main body31. For example, the case main body31and the case cover32are prevented from being separated from the assembled state by locking the locking portions provided on both sides.

An opening33corresponding to the shape of an upper surface of the cover14of the capacitor unit10is provided at a part of an upper surface of the case cover32. When the case30houses the capacitor unit10and the board20, the opening33is closed by the upper surface of the cover14. The case30has been described above.

Above, the capacitor unit10, the board20, and the case30that configure the voltage conversion device1have been described. The voltage conversion device1is obtained by mounting the capacitor unit10on the board20and housing the board20with the capacitor unit10mounted thereon in the case30. A method for manufacturing the voltage conversion device1will be described below.

First, one or a plurality of capacitor units10are selected from among a plurality of capacitor units10including different types of capacitors11(the step corresponds to a “selection step”).

In general, environments such as temperature differ depending on countries and regions, and thus the number of mounted capacitors11and the like differ depending on countries and regions where vehicles in which the voltage conversion device1is mounted are used. Therefore, the capacitor unit10in which the capacitor11corresponding to the country or region is mounted is selected. A type of the capacitor11of the present embodiment includes a capacitance of the capacitor11, the number of mounted capacitors11, and the like, and the type of the capacitor11is a generic term therefor.

Next, the capacitor unit10selected by the selection step is mounted on the board20(the step corresponds to a “mounting step”). Specifically, the capacitor unit10is placed at a predetermined position on the board20, and the screws4are inserted through the screw holes16of the flange15of the capacitor unit10and the screw holes (not shown) of the board20for fastening.

The predetermined position is preferably a position away from the transformer2, and more preferably a position sandwiching the heat sink3between the capacitor unit10and the transformer2. This is because, in a high-temperature environment, a failure in the operation or the like of the capacitor11, or deterioration over time due to power reception at a high temperature may occur. Note that the mounting (attachment) of the capacitor unit10to the board20is not limited thereto.

As shown inFIG.4, when the capacitor unit10is mounted on the board20, the terminal portions18are moved downward while being arranged above the spring terminals21of the board20. Thereby, the terminal portion18and the spring terminal21are elastically and electrically connected. That is, the capacitor unit10and the board20are electrically connected.

Next, the board20on which the capacitor unit10is mounted is housed in the case30(housing step). Specifically, the board20on which the capacitor unit10is mounted is placed on the case main body31, and the case cover32is assembled to the case main body31. Here, the upper surface of the cover14of the capacitor unit10is fitted into the opening33of the case cover32. Thereby, the capacitor unit10and the board20are housed in the case30.

From the viewpoint of waterproofness, it is preferable to provide a waterproof member such as packing between the cover14of the capacitor unit10and the opening33of the case30. Thus, the voltage conversion device1is obtained by the above steps.

For example, when replacing the capacitor unit10, the board20on which the capacitor unit10is mounted may be taken out from the case30, the capacitor unit10may be removed from the board20, a new capacitor unit10may be selected, and the above-described steps may be performed. A method for manufacturing the voltage conversion device1has been described above.

According to the voltage conversion device1according to the present embodiment, the capacitor unit10is detachably attached to the board20. Accordingly, since the capacitor unit10can be replaced with respect to the board20, there is no need to mount more capacitors11than necessary on the capacitor board12. Heat transfer to the capacitor11can be reduced by forming the capacitor11as the capacitor unit10and separately from the board20and the case30. As a result, the voltage conversion device1according to the present embodiment can reduce the number of mounted capacitors11compared to the voltage conversion device of the related arts.

According to the voltage conversion device1according to the present embodiment, even when the voltage conversion device1is accelerated, for example, the capacitor11and the capacitor board12are enclosed by the resin13, and thus the capacitor11is prevented from being detached from the capacitor board12(that is, vibration resistance is improved). Accordingly, there is no need to provide an expensive base unlike the voltage conversion device of the related arts.

As described above, the manufacturing cost of the voltage conversion device1according to the present embodiment is reduced compared to the voltage conversion device of the related arts.

According to the voltage conversion device1of the present embodiment, the upper surface of the cover14of the capacitor unit10is configured to close the opening33provided in the case cover32of the case30. As a result, the height of the case cover32can be matched with the height of the capacitor unit10mounted on the board20, and an increase in the size of the voltage conversion device1can be prevented.

According to the voltage conversion device1according to the present embodiment, the terminal portion18of the capacitor unit10and the spring terminal21of the board20are elastically connected. Thereby, the capacitor unit10and the board20can be easily electrically connected.

The manufacturing method according to the present embodiment can also achieve the above-described “functions and effects” of the voltage conversion device1.

Other Aspects

The present invention is not limited to the above-described embodiments, but appropriate modifications, improvements, and the like are possible. Any material, shape, dimensions, number, location, and the like of each configuration element in the above-described embodiments can be adopted as long as the present invention can be achieved, and are not limited.

Although only one flange15is provided on the cover14of the capacitor unit10in the above embodiment, a plurality of flanges15may be provided. By providing a plurality of flanges15on the cover14, the capacitor unit10is more appropriately prevented from being detached from the board20.

In the above embodiment, the capacitor11was connected to the ground via the terminal portion18, but may be connected to the ground via the flange15and the screw4, which are the fastening portions with the board20, for example.

In the above embodiment, the capacitor unit10is mounted on the board20while the case cover32is removed from the case main body31, but may be configured to be mounted on the board20while the case cover32is assembled to the case main body31. That is, the capacitor unit10may be mounted by inserting the capacitor unit10from the opening33of the case cover32toward the board20.

As shown inFIG.5, the cover14aof the capacitor unit10amay not include the flange portion. Here, the screw hole16amay be provided at the center part of the capacitor board12, for example. As a result, the size of the capacitor unit10acan be reduced.

Here, the features of the voltage conversion device and the manufacturing method according to the present embodiment described above are briefly listed in <1> to <4> below.

<1> A voltage conversion device (1) including:a board (20) on which an electronic component having a power conversion function is mounted; anda capacitor unit (10) detachably attached to the board and electrically connected to the board, in whichthe capacitor unit (10) includesa capacitor (11),a capacitor board (12) on which the capacitor is mounted, andresin (13) by which the capacitor and the capacitor board are enclosed.

<2> The voltage conversion device (1) according to <1> described above, further including:a case (30) that houses the board (20) and the capacitor unit (10), in whicha part of the case (30) is provided with an opening (33), andthe capacitor unit (10) further includes a metal cover (14) that is attached to the resin (13) by which the capacitor (11) and the capacitor board (12) are enclosed and closes the opening (33).

<3> The voltage conversion device (1) according to <1> or <2> described above, in which a spring terminal (21) provided on the board (20) and a terminal portion (18) provided on the capacitor unit (10) are elastically connected.

<4> A method for manufacturing the voltage conversion device (1) according to any one of <1> to <3> described above, the method including:a selection step of selecting one or a plurality of the capacitor units (10) from among a plurality of capacitor units (10) including different types of capacitors (11); anda mounting step of mounting the capacitor unit (10) selected in the selection step on the board (20).

While the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes or modifications can be made without departing from the spirit and scope of the present invention.

The present application is based on Japanese Patent Application (No. 2021-187351) filed on Nov. 17, 2021, and the content thereof is incorporated herein by reference.

INDUSTRIAL APPLICABILITY

According to one embodiment, it is possible to provide a voltage conversion device and a manufacturing method capable of reducing manufacturing cost. The present invention having the effect is useful for voltage conversion devices and manufacturing methods.

REFERENCE SIGNS LIST