JP6952818B2 - Capacitor holding structure and electronic equipment - Google Patents

Description

The present application relates to a capacitor holding structure and an electronic device having a capacitor holding structure.

In vehicles such as electric vehicles or hybrid vehicles that use a motor as one of the drive sources, a charger that converts a commercial AC power source to a DC power source to charge a high-pressure battery, and a DC power source of a high-pressure battery for auxiliary equipment. It is equipped with an electronic device using a power conversion device such as a DC / DC converter that converts the voltage of the battery (for example, 12V or the like) and an inverter that converts the DC power from the battery into AC power to the motor.
In recent years, these electronic devices have been required to be lighter in weight, smaller in size, lower in cost, and more efficient in electric power for the purpose of improving the fuel efficiency of electrified vehicles and expanding the cabin space. It is necessary to reduce the weight, size, cost, and efficiency of each component mounted in the electronic device.

For example, in a power converter built into an electronic device, a capacitor mainly plays a role of storing electric power and smoothing output voltage and current, but when the electric power is stored, the capacitor generates heat. Become. When the heat generation temperature of this capacitor is high, the deterioration of the capacitor is accelerated and the life of the power conversion device is shortened. Therefore, a plurality of capacitors are arranged in parallel or in series to reduce the heat generation temperature per capacitor.
However, in recent years, as the frequency of the semiconductor element switching frequency has been increased for the purpose of miniaturizing the entire power conversion device, the current ripple flowing through the capacitor has also increased, and in order to smooth this current ripple, the electric capacity of the capacitor must also be increased. It doesn't become.
On the other hand, if the capacity of the capacitor is increased, the number of capacitors or the volume of the capacitor itself increases, and the volume of the capacitor is increased even though the switching frequency is increased for the purpose of miniaturizing the power conversion device. Alternatively, the increase in the number is a factor that hinders the miniaturization of the power conversion device.

Therefore, a cooling structure for cooling the capacitor is required in order to suppress the increase in volume or the number of arrangements without impairing the life even if the capacitor generates heat. A method of cooling has been proposed (for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2004-296985

However, in the conventional capacitor holding structure as described above, the holding force of the capacitor in the capacitor holding mechanism is weakened or strengthened due to the temperature change of the capacitor itself or the temperature change inside the electronic device. For example, the holding force of the capacitor is weakened or strengthened. If the force is weakened, the cooling capacity of the capacitor may be reduced or the capacitor may fall off due to vibration. On the other hand, if the pressing force is strengthened, a mechanical load is applied to the capacitor, causing terminal breakage or cracking of the soldered part. Occurrence is possible.
Further, in the conventional capacitor holding structure, the insulation of the peripheral parts of the capacitor is not considered, and in addition, there is no mechanism capable of absorbing the tolerance due to the large dimensional variation of the capacitor shape, and the terminal is broken or solder cracked. There is concern about the occurrence of.

The present application has been made to solve the above-mentioned problems, and an object of the present application is to obtain a capacitor holding structure in consideration of the cooling property, the insulating property, and the vibration resistance of the capacitor.

The capacitor holding structure disclosed in the present application is a capacitor holding structure having a tubular capacitor body and a pair of electrode terminals provided on one end side of the capacitor body, and the electrode terminals of the capacitor are soldered. The first circuit board, which is formed by molding an insulating heat conductive resin into a tubular shape, contains a capacitor, and is made of an insulating heat conductive resin and is arranged between the capacitor and the capacitor holder. A second heat transfer member, a housing formed of a heat conductive material in a tubular shape to fix a circuit board and a capacitor holder, and a second housing made of an insulating heat conductive resin and arranged between the capacitor holder and the housing. It is characterized in that it includes a heat transfer member, and the first heat transfer member and the second heat transfer member are attached to a capacitor, a capacitor holder, and a housing in close contact with each other.

According to the capacitor holding structure disclosed in the present application, the capacitor can be efficiently cooled by arranging a heat transfer member made of an insulating heat conductive resin between the capacitor, the capacitor holder and the housing, and as a result, the capacitor can be cooled efficiently. Deterioration due to heat generation of the capacitor can be suppressed and the life of the capacitor can be extended. In addition, the capacity of the capacitor can be reduced, the required number of capacitors can be reduced, and the size of the electronic device can be reduced.

It is a perspective view which shows the appearance shape of the capacitor used in the power conversion apparatus. It is sectional drawing which shows the outline of the capacitor holding structure which concerns on Embodiment 1. FIG. It is a perspective view which shows a part of the capacitor holding structure which concerns on Embodiment 1. FIG. It is a perspective view which shows unfolding the capacitor holding structure which concerns on Embodiment 1. FIG. It is a perspective view which shows the appearance after assembling of the capacitor holding structure which concerns on Embodiment 1. FIG. It is a perspective view which shows unfolding the capacitor holding structure which concerns on Embodiment 2. FIG. It is sectional drawing which shows the outline of the capacitor holding structure which concerns on Embodiment 2. FIG. It is sectional drawing which shows the outline of the capacitor holding structure which concerns on Embodiment 3. FIG. It is sectional drawing which shows the outline of the capacitor holding structure which concerns on Embodiment 4. FIG. It is sectional drawing which shows the outline of the capacitor holding structure which concerns on Embodiment 5.

Embodiment 1.
Hereinafter, embodiments of the present application will be described with reference to the drawings. In each figure, the same or corresponding parts will be described with the same reference numerals.
1 (a) and 1 (b) are perspective views showing the external shape of a capacitor used in a power conversion device. An aluminum electrolytic capacitor is usually used in the power conversion device, and the capacitor 1 is shown in FIG. As shown in the above, it is composed of a cylindrical capacitor body 1a, a pair of electrode terminals 1b provided on one end side of the capacitor body 1a, and an explosion-proof valve 1c provided on the opposite side of the capacitor body 1a. ing. Here, when a voltage higher than the standard is applied to the capacitor 1 of the explosion-proof valve 1c, the internal pressure may rise and the capacitor body 1a may explode. Therefore, at the time of this explosion, the internal pressure is released and the capacitor is used. It reduces the impact caused by the burst of 1. Since the internal structure of the capacitor body 1a is general, the description thereof will be omitted.

Next, a capacitor holding structure using such a capacitor 1 will be described. FIG. 2 is a cross-sectional view showing an outline of the capacitor holding structure according to the first embodiment, and FIG. 3 is a cross-sectional view of the capacitor holding structure in FIG. A perspective view showing a part, FIG. 4 is a perspective view showing the capacitor holding structure in FIG. 2 in an expanded manner, and FIG. 5 is a perspective view showing the appearance of the capacitor holding structure in FIG. 2 after assembly.

In the figure, the capacitor holding structure 100 refers to the entire holding structure of the capacitor 1, and is formed by forming a tubular capacitor 1 and a resin such as silicon resin having insulating thermal conductivity into a tubular shape. A capacitor holder 2 containing the capacitor 1, a heat transfer member 3 made of a resin sheet having insulating thermal conductivity and arranged between the capacitor 1 and the capacitor holder 2, and above the capacitor 1 as shown in FIG. The capacitor holder 2 and the circuit board 4 are fixed by a fixing screw 6 and are formed of a heat conductive material such as aluminum and a circuit board 4 in which the electrode terminal 1b of the capacitor 1 is soldered and fixed. It is composed of a housing 5 and a heat transfer member 7 made of an insulating heat conductive resin sheet such as silicon resin inserted between the capacitor holder 2 and the housing 5.

Here, as shown in FIG. 4, the heat transfer member 3 and the heat transfer member 7 are mounted at four corners on the opposite side surface of the electrode terminal 1b of the capacitor 1 and the corners of the capacitor holder 2. By providing such a heat transfer member 3 and a heat transfer member 7, the heat transfer member made of resin has elasticity, so that it is between the capacitor 1 and the capacitor holder 2 and between the capacitor holder 2 and the housing 5. The heat transfer property is improved by being pressed when the capacitor is attached to the capacitor, and the vibration resistance can be ensured.

Further, since excessive stress is not applied to the electrode terminal 1b and the soldered portion of the capacitor 1, it is possible to prevent the electrode terminal 1b from breaking or the occurrence of solder cracks. Therefore, even if vibration or impact is applied, the capacitor 1 Will not be damaged. Further, since the sheet-shaped heat transfer members 3 and 7 can be replaced and disassembled after assembly, there is also an effect of improving the yield in the production of electronic devices.

In addition, since the capacitor holder 2 covers the entire capacitor 1, there is an advantage that the insulation between the capacitor 1 and the surrounding conductive components can be maintained.
The heat transfer member 3 is not limited to four mounting locations, and may be formed by a single ring-shaped sheet. Further, by mounting the heat transfer member 3 only on the corner portion on the lower surface of the capacitor 1, it is possible to provide a space on the opposite portion of the explosion-proof valve 1c of the capacitor 1 and suppress the impact when the explosion-proof valve 1c bursts. Is.

The procedure for mounting the capacitor holding structure 100 as described above will be described with reference to FIGS. 3 to 5.
First, as shown in FIG. 3, a pair of electrode terminals 1b in five capacitors 1 for forming a power conversion device are passed through through holes formed at predetermined locations on the circuit board 4, and the upper surface of the capacitor 1 is formed. The electrode terminal 1b is soldered and fixed to the copper foil portion of the circuit board 4 at a position where the electrode terminal 1b is pushed in until it comes into contact with the mounting surface of the circuit board 4.

Next, a heat transfer member 3 is arranged on the bottom surface of the capacitor holder 2 to insert and hold the capacitor 1 from above, and a second heat transfer member 7 is arranged on the bottom surface of the housing 5 to arrange the capacitor 1 and the circuit. The capacitor holder 2 to which the board 4 is assembled is inserted, and the circuit board 4 and the capacitor holder 2 are fastened together with the fixing screw 6 to complete the capacitor holding structure 100 as shown in FIG.

The capacitor holder 2 is formed by molding a resin having good thermal conductivity and insulating properties such as PPS (polyphenylene sulfide), PBT (polybutylene terephthalate), or PET (polyethylene terephthalate) into a tubular shape. A metal bush 2a is inserted at the insertion point of the fixing screw 6 to prevent the condenser holder 2 from cracking due to the tightening of the fixing screw 6. Further, the circuit board 4 is made of, for example, epoxy resin, copper, aluminum, or the like.

As described above, if the capacitor holding structure 100 according to the first embodiment is mounted on an electronic device, the capacitor 1 that generates heat due to the operation of the power conversion device can be cooled, and the deterioration of the capacitor 1 can be suppressed. The life can be extended. As a result, it is possible to reduce the number of capacitors 1 used in the power conversion device, and the effect of reducing the external dimensions of the electronic device can be expected. Further, by reducing the number of capacitors 1 or the electric capacity, it can be expected that the size, cost and weight of the electronic device are reduced, and the productivity is improved by reducing the number of solder points.
As the heat transfer member 3 and the heat transfer member 7, those obtained by previously molding an insulating heat conductive resin into an L-shaped cross section can also be used.

Embodiment 2.
FIG. 6 is a perspective view showing the capacitor holding structure according to the second embodiment in an expanded manner, and FIG. 7 is a cross-sectional view showing an outline of the capacitor holding structure according to the second embodiment.
In the second embodiment, when a plurality of capacitors 1 constituting the power conversion device are arranged close to each other (five in the figure), one heat transfer member 3 and 7 is provided for each of the plurality of capacitors 1. The heat transfer member 3 has a ring shape that covers the outer peripheral side of the capacitor 1.
With such a configuration, in addition to the effect in the first embodiment, the heat transfer member 3 and the heat transfer member 7 can be easily handled, and workability can be improved.

Embodiment 3.
FIG. 8 is a cross-sectional view showing an outline of the capacitor holding structure according to the third embodiment.
The heat transfer member 3 and the heat transfer member 7 are each formed by filling a semi-solidified filler made of an insulating heat conductive resin.
That is, the filler in the semi-solidified state is filled in the gap between the corner portion of the capacitor 1 and the capacitor holder 2 and the gap between the corner portion of the capacitor holder 2 and the housing 5, respectively, and the capacitor 1 and the capacitor holder 2 are pressed against each other. It is configured to function as a heat transfer member that fills each gap.

In this case, the filler has a low viscosity at the time of filling, but after filling, it hardens or increases in viscosity due to heating or moisture, and in the gap between the capacitor 1 and the capacitor holder 2 and the gap between the capacitor holder 2 and the housing 5. It is preferable to use a material such as a two-component room temperature curable heat-dissipating silicone resin that stays.

With this configuration, in addition to the effects in the above-described embodiment, the applied filler can change its shape depending on the dimensional tolerances of the capacitor 1, the capacitor holder 2, and the housing 5, so that the capacitor 1 and the capacitor can be changed. There is an advantage that it is not necessary to consider the variation in dimensions of the holder 2 and the housing 5.

Further, as shown in FIG. 8, by providing the annular wall 2b protruding from the bottom surface of the capacitor holder 2, the filling position of the filler in the semi-solidified state can be kept at the desired portion.
Here, the installation position of the wall 2b is set on the circumference drawn with a diameter smaller than the outer circle of the capacitor 1 centering on the point where the center line of the cylindrical capacitor body 1a is projected onto the capacitor holder 2. It is provided up to a height that does not interfere with.

With such a configuration, the insertion position of the filler constituting the heat transfer member 3 can be easily determined, and the productivity can be improved.

Embodiment 4.
FIG. 9 is a cross-sectional view showing an outline of the capacitor holding structure according to the fourth embodiment.
In the figure, the condenser holder 2 has a circular hole on the bottom surface thereof, and is configured by insert molding a metal plate 9 such as copper or aluminum having excellent thermal conductivity so as to close the hole. A ring-shaped heat transfer member 3 and a heat transfer member 7 on a flat plate are arranged above and below the plate 9.
In this way, the heat of the capacitor 1 is transferred to the heat transfer member 3, the metal plate 9, and the metal plate 9 by replacing the bottom surface of the resin capacitor holder 2 in the first to third embodiments with a metal plate 9 made of copper or aluminum having a high thermal conductivity. It can be efficiently transmitted to the housing 5 via the heat transfer member 7, and the cooling performance of the capacitor 1 can be further improved.

Embodiment 5.
FIG. 10 is a cross-sectional view showing an outline of the capacitor holding structure according to the fifth embodiment.
In the figure, a thermally conductive metal plate 10 made of copper or aluminum is preformed along the shape of the capacitor holder 2, and when the capacitor holder 2 is resin-molded, the metal plate 10 is insert-molded and integrated. It is a thing. At this time, the metal plate 10 is formed so as to be exposed from the resin portion at the portion facing the bottom surface of the capacitor holder 2 and the portion facing the screw fixing portion of the housing 5.
Using such a capacitor holder 2, the capacitor holder 2 is inserted into the tubular shape of the housing 5, a ring-shaped heat transfer member 3 is arranged on the bottom surface, and the capacitor holder 3 is mounted on the circuit board 4 on the heat transfer member 3. After arranging the capacitor 1, the capacitor holding structure 100 is formed by tightening the metal plate 10, the bush 1d of the capacitor holder 2, and the circuit board 4 together with the housing 5 with the fixing screw 6. Become.

With this configuration, the heat generated in the capacitor 1 is transferred to the housing 5 via the ring-shaped heat transfer member 3 and the heat conductive metal plate 10, and moreover, the metal plate 10 Is pressed against the housing 5 by the fixing screw 6, so that the outer peripheral surface of the capacitor 1 and the metal plate 10 and the metal plate 10 and the housing 5 can be brought into close contact with each other to form a stable heat dissipation path. be able to. Further, it is not necessary to provide a heat transfer member between the capacitor holder 2 and the housing 5, and the productivity at the time of assembly can be improved.

In the above-described embodiment, the capacitor holder 2 and the circuit board 4 are fastened together to the housing 5 with the fixing screws 6, but the capacitor holder 2, the circuit board 4, and the housing 5 are different. It may be fixed at the position. Further, it can be applied to the case where a power conversion device is configured by using a capacitor such as a tantalum capacitor or a film capacitor instead of an aluminum electrolytic capacitor as the capacitor 1.

Further, although the present application describes various exemplary embodiments and examples, the various features, embodiments, and functions described in one or more embodiments are specific embodiments. It is not limited to the application of, but can be applied to the embodiment alone or in various combinations.
Therefore, innumerable variations not illustrated are envisioned within the scope of the techniques disclosed in the present application. For example, it is assumed that at least one component is modified, added or omitted, and further, at least one component is extracted and combined with the components of other embodiments.

1: Capacitor, 1a: Capacitor body, 1b: Electrode terminal, 1c: Explosion-proof valve,
2: Capacitor holder, 3: Heat transfer member, 4: Circuit board, 5: Housing,
6: Fixing screw, 7: Heat transfer member, 9, 10: Metal plate

Claims (11)

A capacitor holding structure having a cylindrical capacitor body and a pair of electrode terminals provided on one end side of the capacitor body.
The circuit board to which the electrode terminals of the capacitor are soldered and
A capacitor holder formed by molding an insulating heat conductive resin into a cylindrical shape and accommodating the capacitor,
A first heat transfer member made of an insulating heat conductive resin and arranged between the capacitor and the capacitor holder,
A housing that is formed in a cylindrical shape from a heat conductive material and fixes the circuit board and the capacitor holder.
A second heat transfer member made of an insulating heat conductive resin and arranged between the capacitor holder and the housing is provided, and the first heat transfer member and the second heat transfer member are the capacitor. , A capacitor holding structure characterized in that it is attached to the capacitor holder and the housing in close contact with each other. The capacitor holding structure according to claim 1, wherein the first heat transfer member and the second heat transfer member are formed of a sheet-like resin. The capacitor according to claim 1 or 2, wherein a plurality of the capacitors are arranged side by side and attached to the circuit board, and the first heat transfer member and the second heat transfer member are integrated with each other. Retention structure. The feature is that the first heat transfer member and the second heat transfer member are formed in an L-shaped cross section and arranged at a corner between the capacitor and the capacitor holder and between the capacitor holder and the housing, respectively. The capacitor holding structure according to claim 1. The first heat transfer member and the second heat transfer member are provided with a semi-solidified filler made of an insulating heat conductive resin at a corner between the capacitor and the capacitor holder and between the capacitor holder and the housing. The capacitor holding structure according to claim 1, wherein each of the capacitors is filled and formed. The capacitor holding structure according to claim 5 , wherein a wall protruding in an annular shape is provided on the bottom surface of the capacitor holder. Using the capacitor holder formed by insert-molding a heat conductive metal plate on the bottom surface of the capacitor holder, the first heat transfer member and the second heat transfer member are arranged above and below the metal plate. The capacitor holding structure according to claim 1, wherein the capacitor is held. The capacitor holding structure according to any one of claims 1 to 7, wherein the capacitor is an electrolytic capacitor provided with an explosion-proof valve on the side opposite to the electrode terminal forming side. The capacitor holding structure according to claim 8, wherein the first heat transfer member is configured so that a space is formed in the facing portion of the explosion-proof valve of the capacitor. A capacitor holding structure having a cylindrical capacitor body and a pair of electrode terminals provided on one end side of the capacitor body.
The circuit board to which the electrode terminals of the capacitor are soldered and
Using an insulating heat conductive resin, a heat conductive metal plate that is exposed at the portion facing the other end side of the capacitor body and the portion to be screwed is insert-molded to form a capacitor holder that houses the capacitor. ,
A heat transfer member made of an insulating heat conductive resin and arranged between the capacitor and the metal plate of the capacitor holder.
It is made of a thermally conductive material and is formed in a cylindrical shape, and includes a housing for fixing the circuit board and the capacitor holder.
A capacitor holding structure, characterized in that the heat transfer member is brought into close contact with the metal plate of the capacitor and the capacitor holder, and the metal plate of the capacitor holder is brought into close contact with the housing and fixed. An electronic device comprising a power conversion device having the capacitor holding structure according to any one of claims 1 to 10.

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