JPH1154974A - Electric device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To fully realize miniaturization and cost reduction, by providing a space part of a specified width between an outlet side of an air flow direction of a radiation fin whereon an electric component which requires cooling is mounted and a fan, and by arranging an electric component which requires cooling which is different from that of the electric component. SOLUTION: Each air flow direction of a plurality of heat radiation fins 2 is made to coincide with an air flow direction by each electromotive fan 4, and they are assembled in an arrangement on a straight line, and an air chamber 6 as a space part is ensured between the fins 2 and the electromotive fan. A path of air for introducing air from an outside to a part wherein a snubber resistor 3 is arranged through the fin 2 and for discharging it to an outside by each electromotive fan 4 is formed. Since a plurality of kinds of electric parts can be effectively cooled by a common cooling electromotive fan 4, the size of an electric component can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric device for forcibly cooling electric components using a fan, and more particularly to an electric device suitable for an inverter device having a snubber circuit.

[0002]

2. Description of the Related Art In general, an electric device includes an electric component which generates heat due to a loss associated with an operation and rises in temperature. In this case, there may be no need to provide any cooling means, but in the case of power equipment having a large capacity, radiating fins are provided for electric components that need to be cooled, and the cooling capacity by natural air cooling is increased, and furthermore, In some cases, it is necessary to apply a forced cooling system in which a fan is provided to forcibly ventilate the air. For example, in a well-known inverter device, it is indispensable to apply a forced cooling method using an electric fan to a switching element of a main circuit, which is a main heat-generating component, depending on its rated capacity.

In this inverter device, various resistors including a snubber resistor are used. However, each of these resistors is basically a heating element, and may considerably generate heat depending on electric power to be handled. is there. In particular, the snubber resistor generates a large amount of heat, and therefore, in the conventional inverter device,
This snubber resistor is installed at a position relatively far away from the main heat-generating components such as the switching element of the main circuit,
In general, the temperature rise was suppressed by natural air cooling as it was.

[0004] On the other hand, an inverter device in which a resistor is arranged in a flow path of cooling air by an electric fan is also known in the related art. Further, an electric fan is separately provided, whereby only electric components such as a resistor are independently provided. The method of forcibly cooling is also known as the prior art.

[0005]

In the above prior art, no consideration is given to cooling of electric parts other than the electric parts which need to be forcedly cooled, and there is a problem described below. First, of the above-mentioned prior arts, in the case of natural cooling, since the resistors and the like are heating elements, they have to be disposed relatively far from electric parts such as capacitors and transistors that are weak to heat.

For this reason, there has been a problem that the wiring to some electric components such as a resistor becomes long, and a process such as bundling of electric wires is required, so that the production is troublesome. In addition, as a result of routing a wire through which a large current flows in the main circuit over a long distance, there is a possibility that a new problem may occur electrically.

Further, in this case, the air flow is weak due to natural air cooling, and it is difficult to obtain a uniform air flow, so that it is difficult to obtain a required cooling capacity. As a result, electric components such as resistors are large. There was a problem that had to be converted.

[0008] In addition, there is a problem that an electric component having particularly high heat radiation efficiency is required, and it becomes difficult to cope with a general-purpose product. In addition, there is a problem that the use of the large-sized electric component requires a large arrangement space, and the entire device is enlarged.

On the other hand, even in the case of the forced cooling method using an electric fan, in the prior art, a place where uniform air flow cannot be obtained, such as an upstream side of a heat radiating fin or a back side of a cooling fin, or a relatively low air flow. It was located in a weak place. In this case, it is difficult to obtain a necessary cooling capacity, and as a result, there has been a problem that an electric component such as a resistor must be increased in size.

[0010] Furthermore, as a result, special electric parts having high heat radiation efficiency are required, which makes it difficult to deal with general-purpose products, resulting in having to rely on specially-designed large parts and increasing costs. There was a problem.

When an electric component such as a resistor is arranged on the upstream side of the radiating fin, the temperature of the cooling air increases due to the heat generated by the heat, and the air having the high temperature is generated. The cooling fins are sent to the radiating fins for cooling. As a result, there is a problem that the cooling becomes insufficient and semiconductor components such as transistors having a lower allowable temperature than the resistors are thermally destroyed.

Further, in this case, a space for mounting a resistor in the flow path of the cooling air is required separately, and as a result, there is a problem that the size of the electric device is increased.
Further, in this case, an air chamber having a length of at least 50 mm is required between the radiating fins and the electric fan to regulate the flow of air, and the space formed by the air chamber secures a ventilation path. For this reason, there is a problem that a dead space in which components cannot be arranged in the housing becomes a problem, which increases the size of the apparatus.

Further, in the prior art in which an electric fan is separately provided and only electric components such as resistors are forcibly cooled independently, a space for additional arrangement of the electric fan is additionally required. Therefore, there is a problem that a large increase in cost is inevitable.

SUMMARY OF THE INVENTION An object of the present invention is to provide an electric device which can overcome the problems associated with cooling of electric components and which can be sufficiently reduced in size and cost.

[0015]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an electric device of a forced cooling system using a fan, wherein a space between an outlet side of a heat dissipating fin on which an electric component requiring cooling is mounted and the fan is provided. This is achieved by providing a space portion having a predetermined size in the space, and arranging an electric component requiring cooling separately from the electric component in the space portion.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an electric device according to the present invention will be described in detail with reference to the illustrated embodiments. FIG.
Is an embodiment in which the electric device according to the present invention is applied to an inverter device.
Is a radiation fin, 3 is a snubber resistor, 4 is an electric fan,
5 is a housing, 6 is a chamber.

The semiconductor device 1 forms an upper arm circuit and a lower arm circuit in each phase of the inverter main circuit. For this reason, for example, switching of FETs (field effect transistors), IGBTs (insulated gate bipolar transistors), etc. And a flywheel diode connected in anti-parallel to each of these switching elements. At this time, the main circuit of the inverter device is
In order to handle three-phase AC power, it is customary to configure an arm circuit with three-phase bridge connection (Grenz connection),
Therefore, here, as shown, six semiconductor devices 1 of the same number as the number of upper and lower arm circuits of three phases are used.

The heat radiating fins 2 efficiently transmit the heat generated in the semiconductor device 1 to the air and dissipate the heat. Here, one fin 2 is provided in each of the two semiconductor devices 1. Therefore, three radiating fins 2 are provided as a whole. The snubber resistor 3
A snubber circuit is formed together with a capacitor (not shown) to protect the switching element of the semiconductor device 1 from overvoltage. Therefore, the snubber resistor 3
Six are similarly provided corresponding to each of the semiconductor devices 1. As described above, these snubber resistors 3 generate considerable heat during operation.

The electric fan 4 is for cooling the semiconductor device 1 by forced air. In this embodiment, as shown in FIG.
The air is forcibly circulated to the radiating fins 2 by using a single general-purpose electric fan and sending out the air in the direction of the arrow. The housing 5 is an assembly structural member of the inverter device, and has a function of holding the heat dissipating fins 2, the snubber resistor 3, and the electric fan 4 as shown in the drawing.

At this time, as shown in the figure, the radiating fins 2 are assembled in such a manner that the air flow direction of each radiating fin 2 is aligned with the air flow direction of each electric fan 4 and is arranged in a straight line. The snubber resistors 3 are arranged at this time, and at this time, as also shown, each snubber resistor 3 has a length direction which is the same as the air flow direction by the electric fan 4. The snubber resistors 3 are arranged so as to coincide with each other, so that the area of each snubber resistor 3 as viewed from the air flow direction is minimized.

The chamber 6 secures a predetermined space required for installing the snubber resistor 3 between the radiating fin 2 and the electric fan 4, and the radiating fin 2 is externally provided by the electric fan 4. The snubber resistor 3 is introduced into the portion where the snubber resistor 3 is disposed, and serves to form a passage for air discharged therefrom. For this reason, a U-shaped plate member surrounding a part of the surface of the housing 5 as a bottom surface and surrounding the remaining three surfaces is formed as a member having a substantially rectangular cross section.

More specifically, in this embodiment, first, the size of the electric fan 4 is, for example, 140 mm square from the size of a general-purpose product. Next, the height of the radiating fins 2 is set to about 130 mm in consideration of the size of the electric fan 4 and the size of the housing of the inverter device. The distance between the heat radiating fins 2 and the electric fan 4, that is, the linear length of the air flow passage in the chamber 6 is set to about 150 mm from the viewpoint of uniform wind speed distribution.

Next, the operation of the inverter device according to this embodiment will be described. In a forced air cooling type inverter device using an electric fan, the amount of air blown by the electric fan is controlled in accordance with the temperature inside the device, and when the temperature rise is small, it is common to stop the electric fan. The same applies to the case. Therefore, assuming that the inverter device starts operating, heat is generated in the semiconductor device 1 due to loss, and the temperature starts to rise.

However, under the operating conditions at this time, in short, under operating conditions in which the power being handled is small,
While the amount of heat generated from the semiconductor device 1 is small, the temperature rise can be suppressed to a predetermined value or less only by the heat dissipation action by the natural convection of the radiating fins 2, and at this time, the electric fan 4 is stopped.

On the other hand, when the temperature rise of the semiconductor device 1 exceeds a predetermined value, the operation of the electric fan 4 is started.
The amount of air passing through the radiating fins 2 is increased by forced ventilation. As a result, the heat dissipation capability of the heat radiating fins 2 is increased, and the temperature rise is suppressed to a predetermined value.

In this embodiment, the circulation path of the cooling air by the electric fan 4 at this time is
As a result, the snubber resistor 3 is secured as an installation place. As a result, the snubber resistor 3 is sufficiently exposed to the flow of the air that has passed through the radiating fins 2 and is forcibly cooled. In addition, the temperature rise of the snubber resistor 3 can be reliably suppressed.

Therefore, according to this embodiment, even if the snubber resistor 3 is made small, there is no danger of temperature rise, so that the size of the snubber resistor can be sufficiently reduced.
Further, in this embodiment, as described above, since the snubber resistor 3 is arranged so that the area viewed from the air flow direction is minimized, the flow of air necessary for cooling the heat radiation fins 2 is reduced. Is not disturbed, and as a result, it is possible to eliminate the possibility that the original cooling capacity is reduced due to forced air cooling of the snubber resistor 3.

Further, in this embodiment, two snubber resistors 3 corresponding to one phase are provided for one electric fan 4.
Therefore, uniform air can flow through all the snubber resistors 3 in a well-balanced manner. As a result, a uniform cooling action can be obtained, and the turbulence of the air flow can be reduced. It can be kept sufficiently low.

Further, in this embodiment, the radiating fins 2 on which the two semiconductor devices 1 of each phase are mounted correspond to each electric fan 4 and the snubber is located at a position close to the semiconductor devices 1 of each phase. The resistor 3 is arranged, and the entire configuration is integrated for each phase. As a result, the arrangement of the wires connecting the snubber circuits is the same for all phases, and the length of the wires is shortened. , The protection function by the snubber circuit is sufficiently obtained, and the noise can be suppressed to a small level.

[0030]

According to the present invention, a plurality of types of electric parts can be
Since the cooling can be efficiently performed by the common cooling fan, the size of the electric component can be reduced, and as a result, a small and low-cost electric device can be easily provided.

[Brief description of the drawings]

FIG. 1 is a perspective explanatory view showing an embodiment of an electric device according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Semiconductor device 2 Heat dissipation fin 3 Snubber resistor 4 Electric fan 5 Substrate 6 Chamber

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Satoshi Ibori 7-11-1, Higashi Narashino, Narashino-shi, Chiba Industrial Equipment Division, Hitachi, Ltd. (72) Inventor Naoki Takada 7-1-1, Higashi-Narashino, Narashino-shi, Chiba No. Hitachi Industrial Machinery Division (72) Inventor Satoko Ishii 7-1-1 Higashi Narashino, Narashino City, Chiba Prefecture Hitachi Industrial Machinery Division (72) Keiji Kitazawa 5-chome, Omikamachi, Hitachi City, Ibaraki Prefecture No. 2 In the Omika Plant of Hitachi, Ltd.

Claims (2)

[Claims] In a forced cooling type electric device using a fan, a space portion having a predetermined width is provided between an outlet side in a direction of air flow of a radiating fin on which an electric component requiring cooling is mounted, and the fan. An electrical device, wherein an electrical component requiring cooling different from the electrical component is disposed in the space. 2. The invention according to claim 1, wherein the electric component requiring cooling is a main circuit switching element in the inverter device, and the electric component requiring cooling different from the electric component is a snubber used for a snubber circuit. An electrical device characterized by being a resistor.