JP2014025693A - Cooling device, electronic apparatus mounted with the same, and electric automobile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cooling device which is improved in cooling performance.SOLUTION: A working fluid 12 is forcibly circulate to a heat reception part 4, a heat radiation path 6, a heat radiation part 5, a return path 7, and then the heat reception part 4. A check valve 18 provided at the heat reception part 4 has a valve seat 21 with a valve hole 20, and a valve plate 22 opening and closing the valve hole 20 of the valve seat 21, and is provided with a plane contact surface 29 at the valve seat 21 on the side of the valve plate 22 and at an outer periphery of the valve hole 20, and the valve plate 22 is provided with an opening/closing part 26 which covers the valve hole 20 of the valve seat 21 and the plane contact surface 29.

Description

  The present invention relates to a cooling device, an electronic device equipped with the cooling device, and an electric vehicle.

  Conventionally, this type of cooling device is known to be mounted on a power conversion circuit of an electric vehicle. In an electric vehicle, an electric motor serving as a driving power source is switched by an inverter circuit that is a power conversion circuit.

  A plurality of semiconductor switching elements represented by power transistors are used in the inverter circuit, and a large current of several tens of amperes flows through each element.

  For this reason, as the electric vehicle is driven, the inverter circuit has to be heated and cooled.

  Therefore, conventionally, the inverter circuit has been cooled by a boiling cooling device having a refrigerant radiator and a refrigerant tank at the top and bottom, as in Patent Document 1, for example.

JP-A-8-126125

  That is, in the conventional cooling device, the refrigerant tank is disposed in contact with the semiconductor switching element of the inverter circuit, and the liquefied refrigerant in the refrigerant tank is vaporized by heat from the switching element.

  The vaporized refrigerant is raised to a refrigerant radiator disposed in the upper part, and is condensed to liquefy by cooling there, and the cycle of dropping again to the lower part is repeated.

  That is, the refrigerant is circulated by natural convection to cool the inverter circuit.

  However, in such a natural convection type, the heat of the switching element is transferred to the liquefied refrigerant stored in the refrigerant tank by simple convection heat transfer via the wall (heat transfer surface) of the refrigerant tank. As a result, the heat transfer rate on the heat transfer surface could not be increased, and as a result, the cooling effect of the inverter circuit could not be increased.

  Therefore, the present invention aims to enhance the cooling effect.

  In order to achieve this object, the present invention provides a cooling device that circulates a working fluid to a heat receiving part, a heat radiating path, a heat radiating part, a return path, and the heat receiving part to transfer heat, A check valve for controlling the flow of the working fluid is provided in the vicinity of the heat receiving portion of the return path or in the heat receiving portion. The check valve includes a valve seat having a valve hole and the valve hole of the valve seat. A valve plate that opens and closes, and on the valve plate side of the valve seat, a flat contact surface is provided on the outer periphery of the valve hole, and the valve plate has a valve contact hole and a flat contact surface on the valve plate. An opening / closing part is provided to achieve the intended purpose.

  The present invention is a cooling device that moves heat by circulating a working fluid to a heat receiving part, a heat radiating path, a heat radiating part, a return path, and the heat receiving part, in the vicinity of the heat receiving part of the return path, or the A check valve for controlling the flow of the working fluid is provided in the heat receiving portion, and the check valve has a valve seat having a valve hole and a valve plate for opening and closing the valve hole of the valve seat, On the valve plate side of the valve seat, a flat contact surface is provided on the outer periphery of the valve hole, and the valve plate is provided with an opening / closing portion that covers the valve hole and the flat contact surface of the valve seat. , Cooling effect can be enhanced.

  That is, the present invention provides a check valve for controlling the flow of the working fluid in the vicinity of the heat receiving portion of the return path or in the heat receiving portion, so that the working fluid is converted into a heat receiving portion, a heat radiating path, a heat radiating portion, It is possible to forcibly circulate to the return path and the heat receiving part, and as a result, the cooling effect in the heat receiving part can be made extremely higher than that of the conventional natural circulation type.

  Further, in order to circulate the working fluid spontaneously in this way, the check valve needs to function appropriately in the heat receiving portion. However, the check valve of the present invention includes a valve seat having a valve hole, A valve plate for opening and closing the valve hole of the valve seat, and on the valve plate side of the valve seat, a flat contact surface is provided on the outer periphery of the valve hole, and the valve plate has a valve seat valve. Since the opening and closing part that covers the hole and the flat contact surface is provided, when the check valve is closed, that is, when the valve hole of the valve seat is covered by the opening and closing part of the valve plate, The provided flat contact surface is also covered with this opening / closing part.

  Then, the working fluid is also present between the flat contact surface provided on the outer periphery of the valve hole of the valve seat and the opening / closing part covering it, that is, the valve hole is only covered with the opening / closing part of the valve plate. Instead, the outer periphery of the valve seat is covered with a plane contact surface provided on the outer periphery of the valve hole and the operating fluid that covers the opening / closing part that covers it, and as a result, the valve is closed when the check valve is closed. The function is appropriately exhibited, and as a result, the cooling effect in the heat receiving part can be made extremely higher than that of the conventional natural circulation type.

Schematic of the electric vehicle according to the first embodiment of the present invention. Schematic showing the cooling system Exploded perspective view showing the check valve Partially cut perspective view showing the check valve (A) Cross-sectional view showing the check valve (b) B-part enlarged cross-sectional view of FIG. 5 (a) (C) CC cross-sectional view of FIG. 5 (a) (A) Sectional view showing the check valve (b) Sectional view along line BB in FIG. 6 (a) Graph showing the relationship between wet edge size and normalized temperature ratio

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
As shown in FIG. 1, an electric motor (not shown) that drives an axle (not shown) of an electric vehicle 1 is connected to an inverter circuit 2 that is a power conversion device arranged in the electric vehicle 1.

  The inverter circuit 2 supplies electric power to the electric motor, and includes a plurality of semiconductor switching elements (10 in FIG. 2). The semiconductor switching elements (10 in FIG. 2) generate heat during operation.

  For this reason, in order to cool this semiconductor switching element (10 in FIG. 2), a cooling device 3 is provided.

  The cooling device 3 includes a heat receiving portion 4 and a heat radiating portion 5 that radiates heat absorbed by the heat receiving portion 4, and a working fluid (12 in FIG. 2) serving as a heat medium between the heat receiving portion 4 and the heat radiating portion 5. For example, by providing the heat radiation path 6 and the return path 7 for circulating water), the heat receiving section 4, the heat radiation path 6, the heat radiation section 5, the feedback path 7, and the circulation path serving as the heat receiving section 4 are configured.

  That is, in this circulation path, the working fluid (12 in FIG. 2) is a gas (water vapor in the case of water) or a liquid and a mixed state thereof, the heat receiving part 4, the heat radiation path 6, the heat radiation part 5, the return path 7, It circulates in one direction with the heat receiving part 4.

  As shown in FIG. 2, the heat dissipating part 5 includes a heat dissipating body 8 that releases heat to the outside air.

  The heat dissipating body 8 includes a block body (not shown) in which fins formed by thinly forming aluminum in a strip shape are stacked at a predetermined interval, and a heat dissipating path 6 penetrating the stacked fins.

  And heat is radiated by blowing outside air from the blower 9 onto the surface of the radiator 8. The heat radiation from the surface of the heat radiating body 8 can also be utilized for heating in the electric vehicle 1.

  Further, as shown in FIG. 2, the heat receiving portion 4 is in contact with the semiconductor switching element 10 to absorb heat and a heat receiving space that covers the surface of the heat receiving plate 11 and evaporates the flowing working fluid 12. And a heat-receiving plate cover 14 that forms 13.

  Furthermore, the heat receiving plate cover 14 is provided with an inlet 15 for flowing the liquefied working fluid 12 into the heat receiving space 13 and an outlet 16 for discharging the working fluid 12 from the heat receiving space 13 as a gas.

  That is, the inlet 15 is provided on the upper surface of the heat receiving plate cover 14, and the outlet 16 is provided on the side surface of the heat receiving plate cover 14. The return path 7 is connected to the inlet 15, and the heat dissipation path 6 is connected to the outlet 16. Connected.

  In addition, an inflow pipe 19 that supplies the working fluid 12 into the heat receiving portion 4 is connected to the heat receiving portion 4 side of the return path 7 in a state of protruding into the heat receiving space 13.

  Hereinafter, the inflow pipe 19 in the heat receiving space 13 is referred to as an introduction pipe 17. In this embodiment, a check valve 18 is provided at the inlet portion of the inlet pipe 17 of the inlet pipe 19.

  The operation of the cooling device 3 having such a configuration will be described.

  In the above configuration, when the semiconductor switching element 10 of the inverter circuit 2 starts to operate, electric power is supplied to the electric motor, and the electric vehicle 1 starts to move.

  At this time, when a large current flows through the semiconductor switching element 10, at least several percent of the total power is lost and a large amount of heat is generated.

  On the other hand, when heat is transferred from the semiconductor switching element 10 to the liquid working fluid 12 supplied onto the heat receiving plate 11 in the heat receiving space 13, the liquid working fluid 12 is vaporized and expanded in an instant, and the steam is discharged. The heat flows from the outlet 16 to the heat radiation path 6 and is finally liquefied by condensation in the heat radiation portion 5 to release heat to the outside air.

  After being liquefied by the action of the heat radiating section 5, the working fluid 12 that has released heat flows to the return path 7 and accumulates on the check valve 18 in the inflow pipe 19.

  While the liquefied working fluid 12 gradually increases in the return path 7, the vaporization amount of the working fluid 12 in the heat receiving space 13 decreases, the pressure in the heat receiving space 13 also decreases, and the pressure on the check valve 18 is increased. When the check valve 18 is opened (pressed down) by the pressure of the accumulated working fluid 12 due to the water head, the liquid working fluid 12 is again supplied onto the heat receiving plate 11 in the heat receiving space 13.

  In this way, the working fluid 12 circulates in the cooling device 3 to cool the semiconductor switching element 10.

  Here, the cooling mechanism in the heat receiving space 13 will be described.

  In the heat receiving space 13, the working fluid 12 from the return path 7 is dropped as droplets from the check valve 18 onto the heat receiving plate 11.

  At this time, since a part of the gas is first vaporized and expanded in the introduction pipe 17, it spreads radially as a thin film to the surface of the heat receiving plate 11 on the outer circumference of the introduction pipe 17.

  Since the back surface side of the heat receiving plate 11 is in contact with the semiconductor switching element 10, the working fluid 12 that has become a thin film is heated and vaporized instantaneously.

  Since the atmospheric pressure in the circulation path including the heat receiving space 13 is set lower than the atmospheric pressure, the working fluid 12 is vaporized at a temperature lower than the boiling of water in the atmospheric pressure even if water is used. Can do.

  In this embodiment, by setting the atmospheric pressure to -97 KPa and keeping the inside of the circulation path in a saturated vapor pressure state, the boiling temperature according to the outside air temperature is determined and water can be easily vaporized. The semiconductor switching element 10 can be deprived of heat and cooled.

  Further, when the working fluid 12 is vaporized, the pressure in the heat receiving space 13 increases. However, the working fluid 12 does not flow back to the return path 7 due to the action of the check valve 18, and the discharge port 16 is surely provided. To the heat dissipation path 6.

  By operating the cooling device 3 in this manner, a regular heat receiving and releasing cycle can be performed, and the working fluid 12 can be continuously vaporized in the heat receiving space 13 to cool the semiconductor switching element 10. A large cooling effect can be obtained.

  Here, the most characteristic part of the present embodiment will be described with reference to FIGS.

  The check valve 18 of the present embodiment includes a valve seat 21 having a valve hole 20, a valve plate 22 that opens and closes the valve hole 20 of the valve seat 21, and a case 23 that receives the lower surface of the valve plate 22. ing.

  Further, the valve seat 21 is provided with a through hole 24 communicating with the valve hole 20, and the inflow pipe 19 is connected above the through hole 24.

  Further, the valve plate 22 is provided with a U-shaped kerf 25 on its inner side, whereby an opening / closing part 26 is formed inside the kerf 25. That is, one end side of the valve plate 22 is a fixed part, and the opening / closing part 26 on the other end side is a movable part. In the present embodiment, as described above, the kerf 25 is provided on the outer periphery of the opening / closing part 26, and the outer peripheral part of the kerf 25 also forms a fixed part sandwiched between the valve seat 21 and the case 23. As a result, the opening / closing part 26 forms a movable part that can move stably up and down.

  Furthermore, the upper surface of the case 23 is almost fully open except for the contact surface with the fixed portion of the valve plate 22, and there is a space 27 in which the valve plate 22 can move downward as shown in FIG. 5. Furthermore, a through hole 28 is provided on the lower surface.

  The introduction pipe 17 is connected to the through hole 28.

  In this configuration, as described above, the force that lifts the opening / closing portion 26 of the check valve 18 with the pressure in the heat receiving space 13 is the hydraulic head pressure of the working fluid 12 that has returned to the opening / closing portion 26, and this is lower. In a state where the force is greater than the pressing force, the opening / closing part 26 of the check valve 18 covers the valve hole 20 of the valve seat 21 as shown in FIG.

  For this reason, the working fluid 12 in the heat receiving space 13 does not flow backward and returns to the return path 7 side, and can be reliably discharged from the discharge port 16 to the heat radiation path 6.

  Further, in this embodiment, as can be understood from FIGS. 5 and 6, a flat contact surface 29 is provided on the outer periphery of the valve hole 20 on the valve plate 22 side of the valve seat 21.

  That is, the valve plate 22 side of the valve seat 21 is a plane larger than the opening / closing portion 26 of the valve plate 22, and the valve hole 20 is provided on this plane, and the plane contact surface 29 is provided on the outer periphery thereof.

  The valve plate 22 is formed in a flat plate shape so as to cover the valve hole 20 of the valve seat 21 and the flat contact surface 29. However, the valve plate 22 is formed of a thin metal plate such as stainless steel so that it can be opened and closed. The part 26 is elastically deformed and moved to open and close the valve hole 20.

  Therefore, when the check valve 18 is closed, that is, when the valve hole 20 of the valve seat 21 is covered with the opening / closing portion 26 of the valve plate 22, the flat contact surface 29 provided on the outer periphery of the valve hole 20 of the valve seat 21 is also The opening / closing portion 26 is covered.

  In this state, as shown in FIG. 6B, the working fluid 12 is also present in the gap between the flat contact surface 29 provided on the outer periphery of the valve hole 20 of the valve seat 21 and the opening / closing portion 26 covering it. It becomes a state. That is, the valve hole 20 is not only covered with the opening / closing part 26 of the valve plate 22, but on the outer periphery thereof, a gap between the flat contact surface 29 provided on the outer periphery of the valve hole 20 of the valve seat 21 and the opening / closing part 26 covering the valve hole 20. As shown in FIG. 6B, a thin film-like working fluid 12 as shown by the oblique lines is formed. As a result, the airtightness at the time of closing the check valve 18 is increased and the closing function is appropriately exhibited, whereby the cooling effect in the heat receiving portion 4 can be made extremely higher than that of the conventional natural circulation type. It can be done. Further, the opening / closing portion 26 of the valve plate 22 repeatedly collides with a wide area of the flat contact surface 29 when opening and closing, and therefore there is no flat contact surface 29 and the collision with the narrow annular narrow area of the end surface of the inflow pipe 19 is repeated. Compared to the above, the damage to the valve plate 22 is less, and the durability of the valve plate 22 can be improved.

  6 and 7, the relationship between the formation dimension of the thin film-like working fluid 12 formed between the flat contact surface 29 and the opening / closing portion 26 (hereinafter referred to as a wet edge dimension) and confidentiality is used. explain. From FIG. 6, the wetting edge dimensions in the XY directions are indicated as Wx and Wy, and are expressed as the shortest dimension from the opening edge of the valve hole 20 to the end in each direction of the opening / closing part 26. The graph of FIG. 7 represents the relationship between the wet edge size and the normalized temperature ratio (the ratio between the heat receiving plate temperature Ts and the stable heat receiving plate temperature Tst). The heat receiving plate temperature Ts becomes constant over a certain dimension as the wetting edge dimension increases. This constant temperature is defined as a normalized heat receiving plate temperature Tst. From FIG. 7, it can be seen that the normalized heat-receiving plate temperature ratio (Ts / Tst) tends to increase when the wetting edge dimension W is smaller than 0.2 mm. This is because, when the wet edge size is smaller than 0.2 mm, the confidentiality of the thin film-like working fluid 12 is lowered, so that the reverse flow of the vaporized refrigerant is generated in the check valve 18, and the original refrigerant circulation is impaired. This is because the heat receiving plate temperature Ts rises. Therefore, in order to prevent the backflow of the vaporized refrigerant and stabilize the cooling performance, it is necessary to secure a wet edge size of at least 0.2 mm. However, the maximum value of the wet edge size is a reasonable choice that is about the same as the diameter of the valve hole 20 at most. Even larger than this will lead to an increase in the size of the valve structure itself, which is not very good in terms of design.

  The valve plate 22 of the present embodiment is formed of a metal plate as described above. However, as shown in FIG. 5C, the metal plate is moved from the fixed portion to the movable portion side or from the movable portion to the fixed portion side. Since the rolling direction (represented by an arrow) is used, even if the opening / closing portion 26 of the valve plate 22 repeats up and down at the time of opening and closing and bends, metal fatigue hardly occurs and long-term stability can be ensured.

  Moreover, in this embodiment, the chamfering part 30 is provided in the opening edge of the valve hole 20 like FIG.5 (b). Thereby, when the opening-and-closing part 26 of the valve plate 22 has a convex part in the opening edge of the valve hole 20 at the time of opening and closing, it can suppress that it will damage by contact with the valve plate 22. FIG. That is, the durability of the valve plate 22 can be further improved.

  Further, by providing the chamfered portion 30 at the opening edge of the valve hole 20 as shown in FIG. 5B as described above, the working fluid 12 is allowed to flow outside the valve hole 20 as in the case of FIG. 6B. The thin film-like working fluid 12 as shown by the slanted lines easily spreads between the flat contact surface 29 provided on the opening and the opening / closing part 26 covering the surface, and as a result, the closing function when the check valve 18 is closed is achieved. It can also be increased.

  Furthermore, according to the present embodiment, the valve plate 22 is configured by cutting a metal plate, but the outer peripheral portion and the cut groove 25 are also cut in the cutting direction from the valve seat 21 side to the side opposite to the valve seat 21. That is, since the case 23 side is provided, the burr formed at the time of cutting is directed to the case 23 side, and as a result, the valve seat 21 is not damaged when the valve plate 22 is opened and closed.

  As described above, the present invention provides a check valve for controlling the flow of the working fluid in the vicinity of the heat receiving part of the return path or in the heat receiving part, so that the working fluid is supplied to the heat receiving part, the heat radiating path, the heat radiating part, and the feedback path. Therefore, it is possible to forcibly circulate to the heat receiving part, and as a result, the cooling effect in the heat receiving part can be made extremely higher than that of the conventional natural circulation type.

  Further, in order to circulate the working fluid spontaneously in this way, the check valve needs to function appropriately in the heat receiving portion. However, the check valve of the present invention includes a valve seat having a valve hole, A valve plate for opening and closing the valve hole of the valve seat, and on the valve plate side of the valve seat, a flat contact surface is provided on the outer periphery of the valve hole, and the valve plate has a valve seat valve. Since the opening and closing part that covers the hole and the flat contact surface is provided, when the check valve is closed, that is, when the valve hole of the valve seat is covered by the opening and closing part of the valve plate, The provided flat contact surface is also covered with this opening / closing part.

  Then, the working fluid is also present between the flat contact surface provided on the outer periphery of the valve hole of the valve seat and the opening / closing part covering it, that is, the valve hole is only covered with the opening / closing part of the valve plate. However, the outer periphery of the valve seat is covered with the flat contact surface provided on the outer periphery of the valve hole of the valve seat and the opening and closing portion covering the same, and the airtightness is increased. The closing function at the time of closing is appropriately exhibited, whereby the cooling effect in the heat receiving part can be made extremely higher than that of the conventional natural circulation type.

  For this reason, it is useful for cooling power semiconductors used in power conversion devices as drive devices for electric vehicles, CPUs with high heat generation, and the like.

DESCRIPTION OF SYMBOLS 1 Electric vehicle 2 Inverter circuit 3 Cooling device 4 Heat receiving part 5 Heat radiating part 6 Heat radiating path 7 Return path 8 Radiator 9 Blower 10 Semiconductor switching element 11 Heat receiving plate 12 Working fluid 13 Heat receiving space 14 Heat receiving plate cover 15 Inlet 16 Outlet 17 Introduction pipe 18 Check valve 19 Inflow pipe 20 Valve hole 21 Valve seat 22 Valve plate 23 Case 24 Through hole 25 Groove 26 Opening / closing part 27 Space 28 Through hole 29 Plane contact surface 30 Chamfering part

Claims (8)

A cooling device that circulates working fluid to a heat receiving part, a heat radiating path, a heat radiating part, a return path, and the heat receiving part to transfer heat,
A check valve for controlling the flow of the working fluid is provided in the vicinity of the heat receiving part of the return path or in the heat receiving part. The check valve has a valve seat having a valve hole and the valve hole of the valve seat. A flat contact surface on the outer periphery of the valve hole on the valve plate side of the valve seat, and the valve plate and the flat contact surface of the valve seat on the valve plate The cooling device which provided the opening-and-closing part which covers. The cooling device according to claim 1, wherein one end side of the valve plate is a fixed portion, the other end side is a movable portion, and an opening / closing portion is provided between the movable portion and the fixed portion. The cooling device according to claim 2, wherein the valve plate is made of a metal plate, and the metal rolling direction is from the fixed part to the movable part side direction or from the movable part to the fixed part side direction. The cooling device according to any one of claims 1 to 3, wherein a chamfered portion is provided at an opening edge of the valve hole. The cooling device according to any one of claims 1 to 4, wherein the valve plate is configured by cutting a metal plate, and a cutting direction thereof is from the valve seat side to the side opposite to the valve seat. The cooling device according to any one of claims 1 to 5, wherein the shortest dimension from the opening edge of the valve hole to each end of the opening / closing part is 0.2 mm or more and smaller than the diameter of the valve hole. The electronic device provided with the cooling device as described in any one of Claims 1-6, and the heat-emitting component cooled with this cooling device. An electric vehicle comprising the cooling device according to any one of claims 1 to 6 and a heat generating component cooled by the cooling device.

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