JPS6232621B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a water cooling device for electric circuit elements, and more particularly to a water cooling device suitable for cooling semiconductor elements, resistance elements, or reactor elements to which high voltage is applied.

Generally, when semiconductor elements or resistance elements are cooled using water, those elements are attached closely to the outer surface of a water cooling fin that has water channels inside, and water is poured into the internal water channels of the water cooling fin. A method of cooling by flowing water is used.

In addition, when cooling the reactor element using water, the reactor element itself is made hollow, in other words, the reactor element is formed by forming a metal pipe into a spiral shape, and water is allowed to flow inside the pipe to cool the reactor element. Be taken. In this case, the metal pipe itself serves as the water cooling fin.

Metals with high thermal conductivity such as Au, Ag, Cu, and Al are suitable as materials for the cooling fins, but in reality, it is recommended to use the cheaper metals Cu, Al, or alloys containing these as main components. is common.
However, when these metals are immersed in water and a DC voltage is applied, many of the metals dissolve in the cooling water on the anode side due to electrochemical action, and the metals are deposited on the cathode side.

Further, when devices having these water cooling fins are connected in series and used, the water channels of each cooling fin are connected by a water pipe made of an insulating material. At this time, some of the metal ions dissolved in the cooling water adhere to the inner surface of the insulating water pipe, and this adhesion of metal ions is particularly important when the cooling system is operated for a long period of time. This tends to reduce the insulation of the water pipes, increase the pipe friction coefficient of the water pipe wall surface, and increase the friction loss of cooling water. Further, there is a risk that holes may be formed in the cooling fins due to melting of the metal of the cooling fins, and water may leak from the holes.

Conventionally, in order to prevent these problems, a joint made of a conductive and corrosion-resistant metal such as stainless steel was provided at the joint between the cooling fin and the insulating water pipe, so that current could flow from the joint. It is known that there is no current flow from the cooling fins made of Al or Cu, so that the metal of the cooling fins does not melt, and the metal fittings themselves do not dissolve in water. There is.

To explain this configuration in more detail using diagrams, Figure 1 shows an example where the configuration is applied to a resistor (or transistor, thyristor, etc.), and electric circuit element 1 (resistor, transistor, thyristor, etc.) is made of Cu. The cooling fin 2 is closely attached to one surface of the water cooling fin 2, and both ends thereof are connected to the positive and negative electrodes of a DC power source 3, respectively, in terms of an electric circuit. Further, water channels 4 are formed inside the water cooling fins 2 . One end of the water channel 4 is connected to an insulating water pipe 7 via a joining fitting 5 made of stainless steel (SUS), and the other end is connected to an insulating drain pipe 8 via a joining fitting 6 made of SUS. . The cooling water from the drain pipe 8 is sent out again to the water pipe 7 by the pump 9. Therefore, the cooling water is
It will flow in a circular manner along the route "9-7-5-4-6-8-9". Note that a cooling device (not shown) is provided before or after the pump 9, and water cooled to a predetermined temperature is always sent to the water pipe 7.

In this water cooling system, when a voltage from a DC power source 3 is applied to both ends of the electric circuit element 1 and the water cooling fin 2, an anode portion and a cathode portion as shown in the figure are generated at each part. As a result, a direct current voltage is effectively applied to the water cooling fin 2 and the pump 9, and the water pipe 7 and the drain pipe 8
Electric current flows through the cooling water inside. Therefore, in the water supply and drainage pipe section
If SUS joint fittings 5 and 6 are not available, the water channel 4
A large amount of Cu is dissolved from the water cooling fins that connect the water pipes 7 and drain pipes 8, and this dissolved Cu is deposited on the inner surfaces of the water pipes 7 and drain pipes 8. There is a risk that the tube will no longer function as an insulating tube. However, if there are, for example, SUS fittings 5 and 6 at the joint between the cooling fin and the insulating water pipe (or drain pipe), the current will flow from the fitting and not from the cooling fin. There is no melting of the cooling fin metal or joint metal fittings, no accumulation of molten Cu on the inner surface of the insulating water supply and drainage pipes, and no holes in the cooling fins.

It is true that this type of device is very effective as a cooling device for general electric circuit elements, but as electric circuit elements have become more compact in recent years, the aforementioned joining fittings themselves must also be made smaller. In this case, simply downsizing (shortening and lengthening)
The current that should flow from the joint fittings also flows from the water channel surface of the cooling fin, and as mentioned above, the cooling fins will melt, making it impossible to downsize (shorten and lengthen) the joining fittings very much. This has been a problem with miniaturization of electric circuit elements.

The present invention has been made in consideration of this, and its purpose is to shorten the length of the joining fittings, that is, to reduce the dissolution of metal into the cooling water in this type of electric circuit even when downsized. The present invention provides a cooling device for an element.

That is, the present invention provides a wire gauze made of an alloy containing Fe, Ni, and Cr as main components, which is electrically conductive to the joint metal fitting and at the connecting end of the external waterway on the inner surface of the metal fitting. It is designed to achieve the purpose.

The present invention will be explained below based on the illustrated embodiments.

Figure 2 shows a cross section of the area around the joint, and Figure 3 shows the front of the joint.
is a water cooling fin, and 6 is a joining metal fitting. A water channel 4 is formed inside the water cooling fin 2, and a joining fitting 6 is fixed to the water supply end (or drainage end) of the water channel 4.

An insulating water pipe (or drain pipe) is connected to the end of the joining fitting 6, but it is omitted here.

Further, a wire mesh 10 is provided at the end of the joining metal fitting 6 and on its inner surface. The wire mesh 10 is made of Fe, Ni,
It is made of an alloy containing Cr as a main component, and is fixed to the joining metal fitting 6 so as to be electrically conductive thereto.

With this configuration, most of the current flowing in the cooling water flows out from the wire mesh 10 or flows out from the wire mesh 1.
0, that is, the flow of current from the back of the joint 6 (on the side of the water cooling fin) is suppressed. Therefore, even if the length of the joint 6 is shortened, corrosion of the water cooling fin is sufficiently suppressed. The effect of this can be obtained.

In the above explanation, the case has been explained in which the joint fitting is fixed to the channel end of the water cooling fin, but for example, as shown in FIGS. Alternatively, the wire mesh 10 may be made of woven wire or a lattice pattern, and the same effect can be obtained.

Next, in FIG. 6, the conventional cooling device and the cooling device of the present invention will be compared in terms of their effects. This figure shows the relationship between the distance (depth) from the end of the joint to the water cooling fin and the current density.

The curve X consisting of a dotted line is the conventional one, and it can be seen that the current density decreases as it goes deeper, but it penetrates deeper. On the other hand, the solid curve Y is that of the present invention, and the current density rapidly decreases as it goes deeper, and it can be seen that when the two depths are compared at the same current density, it becomes about 1/5.

This means that in the case of the present invention, the length of the joining fittings can be reduced to 1/5 of that of the conventional fittings, which means that it is possible to make the fittings extremely compact.

Also, the shortening of the length of this metal fitting means that if the overall length of the cooling system is the same as before, the length of the insulating water pipe can be increased by the shorter metal fitting. , the electrical resistance of the water channel increases, which makes it possible to suppress the flowing current, which is also effective in reducing the amount of corrosion of the water cooling fins.

As described above, the present invention provides a wire mesh that is electrically conductive to the joint metal fitting and is made of an alloy containing Fe, Ni, and Cr as main components, on the inner surface of the joint metal fitting and at the connection end with the external water channel. If you set up
It is possible to obtain a cooling system for this type of electric circuit element in which sufficient current is collected at the ends of the joint metal fittings and the length of the joint metal fittings is shortened, that is, even when the metal fittings are downsized, there is extremely little dissolution of metal into the cooling water. can.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing a conventional water cooling device for electric circuit elements, and Fig. 2 shows the main parts of the water cooling device for electric circuit elements of the present invention. 3 is a front view seen from the direction of arrow P in FIG. 2, FIG. 4 is a longitudinal side view of another embodiment of the present invention showing the same part as FIG. 3, and FIG. FIG. 4 is a front view seen from the direction of arrow P, and FIG. 6 is a curve diagram showing the relationship between the depth and current density of the joining metal part. 1... Electric circuit element, 2... Water cooling fin, 3
...DC power supply, 4...Waterway, 5, 6...Joining fittings, 7...Water pipe, 8...Drain pipe, 9...Pump, 10...Wire mesh.

Claims (1)

[Claims] 1. A water cooling fin for cooling electric circuit elements that is made of a metal that easily dissolves in cooling water under high electric field strength and has a water channel formed inside, and the internal water channel of the fin is used as an external water channel for supplying and draining cooling water. It is equipped with a joining fitting for connection, and this joining fitting is made of Fe, Ni, Cr.
In a water cooling device for an electric circuit element formed of an alloy mainly composed of Fe, Ni A water cooling device for an electric circuit element, characterized in that it is provided with a wire mesh made of an alloy whose main component is Cr.