WO1999039145A1 - Heat pipe type cooling device, method of producing the same and cooling plate for heat pipe type cooling device - Google Patents

Abstract

A heat pipe type cooling device capable of efficiently cooling a cooling plate according to heat reception comprises a cooling plate (3) of which one side is a heat receiving surface and of which the other side is a heat dissipating surface and a heat pipe (10) buried in the cooling plate (3). A plurality of heat dissipating fins are provided on the heat dissipating surface.

Description

 Specification

 TECHNICAL FIELD The present invention relates to a heat pipe type cooling device, a method of manufacturing the same, and a cooling plate for the heat pipe type cooling device.

 The present invention relates to a heat pipe type cooling device, and particularly to a heat source suitable for cooling a power conversion device such as an inverter device for a main motor, a converter device, or an inverter device for an auxiliary power source mounted on an electric vehicle. It is related to a top pipe cooling device. Background art

 A conventional heat pipe type cooling device is configured, for example, as shown in FIG. 1 of JP-A-3-133165 (Prior Art 1) and FIG. 1 of JP-A-4-1225790 (Prior Art 2). Have been.

 That is, in the above prior art 1, a heating element is mounted on one side of a cooling plate, a hole is formed in the thickness direction from the other side, a heat pipe is inserted into the hole, and the cooling fin is further cooled. It is formed on the thickness side of the plate.

 On the other hand, in the above-mentioned prior art 2, a concave groove is formed on one side surface of the cooling plate, and a heat pipe is mounted in the concave groove.

 In the above prior art 1, since the heat pipe is embedded in the thickness direction of the cooling plate, the contact area between the cooling plate and the heat pipe becomes smaller than the plate thickness of the cooling plate and becomes smaller, and the cooling plate receives the heat pipe. The heat cannot be effectively transmitted to the heat pipe, and since the heat radiation fins are formed on the thickness side of the cooling plate, the number of heat radiation fins is small, and there is a problem that efficient cooling cannot be performed.

Further, in the above prior art 2, no consideration is given to the case where the refrigerant liquid in the heat pipe freezes and loses the function of the heat pipe, and cooling is performed according to heat reception. There is a problem that the plate cannot be cooled efficiently. Disclosure of the invention

 An object of the present invention is to provide a heat pipe type cooling device capable of efficiently cooling a cooling plate according to heat reception.

 In order to achieve the above object, the present invention provides a heat pipe type cooling device comprising a cooling plate having one side as a heat receiving surface and the other side as a heat releasing surface, and a heat pipe embedded in the cooling plate. A plurality of heat radiation fins were provided on the heat radiation surface.

 Since a plurality of radiating fins are also provided on the radiating surface side of the cooling plate as in the above configuration, efficient cooling can be achieved by radiating heat from the heat pipe and radiating heat from the radiating fin, and Even if the refrigerant liquid freezes and loses its function, heat is radiated by the radiating fins, so that a decrease in cooling efficiency can be minimized. BRIEF DESCRIPTION OF THE FIGURES

 FIG. 1 is a longitudinal side view showing an embodiment of a heat pipe type cooling device according to the present invention.

 FIG. 2 is an enlarged cross-sectional view taken along the line III-III of FIG.

 Fig. 3 is an enlarged view of Fig. 2 before caulking the heat pipe.

 Fig. 4 is an equivalent view of Fig. 1 showing another embodiment of the heat pipe type cooling device as viewed from the right side.

 FIG. 5 is a cross-sectional view taken along the line VV of FIG. 4, wherein (a), (b), (c), and (d) show different cross-sectional shapes.

FIG. 6 shows a power conversion to which the heat pipe type cooling device according to the present invention is applied. Block diagram showing the electrical circuit of the switching device for the u phase, and omitting the V and W phases. BEST MODE FOR CARRYING OUT THE INVENTION

 Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 3 by taking a power conversion device mounted under the floor of an electric vehicle as an example.

 A cooling plate 3 is installed so as to cover the opening 2 of the electrical equipment box 1 that stores electrical equipment that dislikes dust, moisture, and water droplets among the electrical equipment required as a power converter. This cooling plate 3 is secured to the peripheral edge 2F of the opening 2 by a well-known fastening means, for example, through packing (not shown), if necessary, in order to secure airtightness in the electrical equipment box 1. Installed.

 Further, the cooling plate 3 is formed of a good heat conductive material such as copper or aluminum, and the side facing the inside of the electric equipment box 1 is a flat heat receiving surface, and the side facing the outside of the electric equipment box 1 is Heat dissipation surface. On the heat radiating surface side of the cooling plate 3, a plurality of heat radiating fins 4 projecting substantially perpendicular to the heat radiating surface and extending over the entire height of the cooling plate 3 are provided in parallel in the vertical direction. A concave groove 5 is provided at the bottom between adjacent heat radiation fins 4 for every four or more heat radiation fins, and every three heat fins in FIGS. 2 and 3. The concave groove 5 is provided so as to be parallel to the heat radiating fins 4 and has a length extending over the entire height of the cooling plate 3. The concave groove 5 is a groove in which a heat pipe 10 described later is embedded, and has a cross-sectional shape similar to the outer shape of the heat pipe 10 in order to secure a contact area with the heat pipe 10. That is, when the outer shape of the heat pipe 10 has a circular cross-section, the heat pipe 10 is formed in the concave groove 5 having a semi-circular cross-section facing approximately 180 degrees of the circular cross-section.

Small sides 6a and 6b are provided on both sides of the opening edge of the concave groove 5 over its entire length. The protruding dimensions of these small sides 6a and 6b are as follows. When the small sides 6a and 6b are caulked with the groove embedded in the concave groove 5, a length that covers the remaining 180 degrees of the circular cross section of the heat pipe 10 is required. As described above, the cooling plate 3 having a plurality of heat radiating fins 4, concave grooves 5, and small sides 6a and 6b improves productivity by, for example, extruding aluminum by extrusion molding using a die. I do. However, if not mass-produced, the cooling plate 3 may be formed by forming the concave groove 5 in a flat plate by cutting and screwing the ripe fin 4.

 On the heat receiving surface of the cooling plate 3 having the above configuration opposite to the heat radiating fins 4, heat generated by a gate-insulated bipolar transistor transistor, which is a part of a component constituting the power converter, is generated. Install part 9.

 On the other hand, the heat pipe 10 buried in the concave groove 5 is formed in a circular cross section, is bent about 95 degrees at an intermediate portion, and is formed in an L-shape as a whole. Is the heat receiving part 11 and the other side is the heat radiating part 12. In such a heat pipe 10, a refrigerant having a volume substantially corresponding to the volume of the heat receiving portion 11 is sealed. In addition, a large number of about 50 radiating fins 13 are attached to the radiating section 12 by press fitting.

 When the heat receiving portion 11 of the heat pipe 10 thus formed is buried in the concave groove 5, as shown in FIG. 3, the heat receiving portion 11 is inserted into the concave groove 5. The crimping tool 14 presses the small sides 6a and 6b at the edge of the concave groove 5. Due to the pressing by the crimping tool 14, the small sides 6a and 6b are plastically deformed so as to surround the heat receiving portion 11 of the heat pipe 10 and adhere to each other. Due to the plastic deformation of the small sides 6a and 6b due to this caulking, the heat receiving portion 11 can be always kept in a pressure contact state in the concave groove 5.

By the way, the crimping tool 14 has a concave curved surface portion 15 at the distal end so as to plastically deform the small sides 6 a and 6 b so as to surround the heat receiving portion 11. As a method of plastically deforming the small sides 6a and 6b by using the crimping tool 14, such as a method of fixing the crimping tool 14 to a punch and lowering it by a press machine, or a method of caulking. There is a method of caulking by so-called roll forming in which a roll capable of rotating the tool 14 and rolling on the small sides 6a and 6b while applying pressure is used. Can be.

 As described above, the cooling plate 3 having the heat-generating electric parts 9 attached to the heat-receiving surface side and the heat pipe 10 attached to the heat-dissipating surface side is used as shown in FIG. Fix so that opening 2 of box 1 is closed. When attaching the cooling plate 3 to the electric equipment box 1, be careful about the direction of the heat radiation fins 4. In the present embodiment, by mounting the radiating fins 4 so as to face up and down, it is possible to follow the flow of the outside air due to natural convection, and to perform efficient cooling.

 In the above embodiment, one cooling plate 3 is provided, and the heat radiating fins 4, the heat-generating electric components 9, and the heat pipe 10 are mounted on the cooling plate 3. However, the cooling plate 3 may be configured by assembling a plurality of small cooling plates 3 as shown in FIG. 4 in consideration of ease of assembly and handling. That is, it has the same height dimensions as the cooling plate 3, like the cooling plate 3, mounts the heat-generating electric parts 9 with one side as a heat-receiving surface, and heats the heat-radiating fins 4 with the other side as a heat-radiating surface. The small cooling plates 3 U, 3 V, 3 W provided with the main pipe 10 are connected to the opening 2 of the electric equipment box 1 and fixed.

When mounting multiple small cooling plates 3U, 3V, 3W in a row, the electrical equipment box should be between the opposing adjacent cooling plates 3U—3V, 3V—3W between the boundary surfaces 7a, 7b. In order to prevent dust, moisture, and water droplets from entering the inside, engaging recesses parallel to the heat radiating fins 4 and the concave grooves 5 as shown in FIG. 8a and the engaging projection 8b are formed. As shown in (a) of FIG. 5, the engaging concave portions 8a and the engaging convex portions 8b are formed by the engaging small portions of the adjacent small cooling plates 3U—3V and 3V-3W, respectively. 8b and the engaging recess 8a are fitted and adhered to each other with a slight tolerance, preventing invasion of outside air and moisture from the boundary surfaces 7a and 7b.

 When fitting the engaging projection 8b and the engaging recess 8a, an adhesive is applied between the engaging projection 8b and the engaging recess 8a or a packing is interposed. However, the airtightness of the interface between adjacent cooling plates can be improved. By the way, according to the above embodiment, the fitting structure between the engaging concave portion 8a and the engaging convex portion 8b is, as shown in (a) of FIG. 5 and (c), (d) in FIG. 5, two sets of rectangular engaging recesses and engaging projections are respectively provided. There is a configuration in which the parts are fitted, a configuration in which a set of cranks are engaged, and a configuration in which a set of semicircular engagement recesses and engagement projections are fitted. It is necessary to make sure that the boundary surfaces 7a and 7b between the adjacent cooling plates 3U, 3V and 3W do not become linear plane division surfaces.

 Further, in another embodiment according to the present invention, as shown in FIG. 6, a heat generating electric component 9 for one phase consisting of four series gate-insulated bipolar transistors, diodes, etc., is used. As shown in the figure, by mounting them on the small cooling plates 3U, 3V, 3W respectively, the assembly work and maintenance work can be performed in units of small cooling plates 3U, 3V, 3W. It will be easier. When fitting the engaging concave portion 8a and the engaging convex portion 8b of the boundary surfaces 7a, 7b of the adjacent small cooling plates 3U, 3V, 3W, the engaging concave portion 8a and the engaging convex portion 8b are engaged. By applying an adhesive or interposing a packing between the portions 8b, the airtightness of the boundary surfaces 7a and 7b can be improved.

With the above configuration, the cooling plate is The surface facing the electrical equipment box 1 of 3 becomes a heat receiving surface, and absorbs heat generated from the electrical equipment in the electrical equipment box 1 and heat generated from the heat generating electrical components 9 mounted on the cooling plate 3. The heat transmitted to the heat receiving surface is guided to the heat radiating surface of the cooling plate 3 facing the outside air, and is released into the outside air by the heat radiating fins 4 and the heat pipe 10.

 During normal operation, the heat transmitted to the radiating surface is released from the radiating fins 4, the heat pipe 10 and the radiating surface of the cooling plate 3. Heat is mainly dissipated by the heat dissipating fins 13 of the heat pipe 10. When the electric vehicle is stopped, no running wind is generated, and the outside air mainly due to natural convection comes into contact with the radiation fins 4 extending in the vertical direction and the radiation surface of the cooling plate 3, thereby radiating heat.

 On the other hand, during the winter in a cold region, after the operation is stopped, the evaporated refrigerant in the heat pipe 10 freezes as it is condensed in the heat radiating section 12 and does not return to the heat receiving section 11, a so-called dryout phenomenon may occur. There is. If the refrigerant freezes in the heat radiating section 12 and does not return to the heat receiving section 11, the refrigerant is not present in the heat receiving section 11 at the time of start-up, and even if there is a small amount, the refrigerant is transmitted to the cooling plate 3. Heat cannot be transferred to the heat radiating section 12 to dissipate heat, and the heat-generating electrical components 9 may be thermally damaged.

 In consideration of the occurrence of the dry heat phenomenon, a short heat pipe shorter than the heat pipe 10 is provided separately from the heat pipe 10 to intentionally lower the cooling performance and raise the temperature. It is also conceivable that the function of the heat pipe 10 is restored by melting the frozen refrigerant in the heat receiving section 11.

However, according to the present embodiment, at the time of start-up or when the traveling wind of low-speed traveling immediately after the start-up is small, natural convection occurs even if the heat pipe 10 does not function. Outside air from the cooling plate 3 makes contact with the radiating fins 4 that are integral with the cooling plate 3, creating a temperature difference between the inside and outside of the cooling plate 3. Since the heat is transmitted to the outside of the plate 3 and is radiated from the radiating fins 4, overheating of the heat-generating electric component 9 can be suppressed. During that time, the refrigerant frozen in the heat radiating portion 12 of the heat pipe 10 melts, so that the heat pipe 10 performs its original function.

 Therefore, according to the present embodiment, cooling plate 3 can be efficiently cooled according to the heat reception.

 According to the present embodiment, the heat radiation fin 4, the concave groove 5, the small side 6a,

6b, the cooling plate 3 having the engaging concave portions 8a and the engaging convex portions 8b of the boundary surfaces 7a and 7b can be integrally formed by extrusion, so that a hole is required for mounting the heat pipe 10 therein. Since there is no need for a machine to be provided, manufacturing is simplified.

 Furthermore, when a plurality of small cooling plates 3U, 3V, 3W are used in series, the boundary surfaces 7a, 7b of the adjacent cooling plates extend along the vertical direction, so that dust and water droplets are not drawn. a, 7 b

It is possible to prevent entry into the electrical equipment box 1 from 7a and 7b. By the way, in the above embodiment, the small sides 6 a and 6 b provided at the edge of the concave groove 5 at the same length as the heat radiation fin 4 are caulked over the entire length after the heat pipe 10 is attached, and the plastic Although it is to be deformed, the caulking is not necessarily performed for the entire length, but may be performed partially, for example, only one side or discontinuously on both sides.

Also, depending on the degree of caulking of the small sides 6a and 6b, a slight gap remains between the concave groove 5 and the surface of the heat pipe 10. However, if a slight gap exists between the groove 5 and the surface of the heat pipe 10, the contact thermal resistance increases. Heat conduction efficiency and crevice corrosion. In such a case, the surface of the heat receiving portion 11 of the heat pipe 10 is coated with a soft metal film 16 of low hardness, such as solder, tin, or lead, and is put into the groove 5. By caulking the small sides 6a and 6b, it is possible to suppress the increase in the re-contact thermal resistance, which eliminates the above-mentioned gap, and also to prevent the occurrence of the gap corrosion.

 As another method for reducing the generation of the above-mentioned gap, a filler having good heat conductivity, a sheet-like soft metal is applied or wound on the surface of the heat receiving portion 11 of the heat pipe 10 or a concave groove is used. The heat receiving portion 11 is inserted into the concave groove 5 while being applied or spread in the inside of the groove 5, and the crimping work is performed in this state, so that the generation of the gap can be eliminated. Furthermore, after the caulking operation is completed, a resin having good thermal conductivity may be permeated by vacuum impregnation or the like to eliminate the gap.

 As described above, according to the present invention, it is possible to obtain a heat pipe type cooling device capable of efficiently cooling a cooling plate according to heat reception.

Claims

The scope of the claims  1. In a heat pipe type cooling device equipped with a cooling plate having one side as a heat receiving surface and the other side as a heat radiating surface, and a heat pipe buried in this cooling plate, a plurality of heat radiating fins are provided on the heat radiating surface. A heat pipe type cooling device characterized by being provided.  2. In a heat pipe type cooling device equipped with a cooling plate having a heat receiving surface on one side and a heat radiating surface provided with a plurality of parallel heat radiating fins on the other side, and a heat pipe attached to the cooling plate. A groove is provided in the heat radiation surface in parallel with the heat radiation fin, the heat pipe is embedded in the groove, and the heat pipe is fixed by plastically deforming an edge of the groove. One-pipe cooling system.  3. A small side for caulking parallel to the heat radiation fin is provided at an edge of the concave groove, and the heat pipe is fixed in the concave groove by caulking the small side. The heat pipe type cooling device according to claim 2, wherein  4. The heat pipe type cooling device according to claim 3, wherein a height of the small side before caulking protrudes from a buried heat pipe. 5. The heat pipe type cooling device according to claim 2, wherein a portion of the heat pipe embedded in the concave groove is covered with a soft metal film.  6. The heat pipe type cooling device according to claim 2, wherein the cooling plate has a heat generating electric component fixed to the heat receiving surface. 7. The cooling plate is constituted by adhering a plurality of small cooling plates having boundary surfaces along the vertical direction at both ends in the width direction with the boundary surfaces being in close contact with each other, and adjacent to the boundary surface of each of the small cooling plates. 7. A step according to claim 2, 3, 4, 5, or 6, wherein a step in the thickness direction is provided which coincides with a boundary surface of the small cooling plate to be formed. One pipe cooling system.  8. The heat pipe type cooling according to claim 7, wherein the cooling plate is fixed by closing the opening of the electric equipment box with the heat receiving surface inside. 9. One side is a heat-receiving surface, the other side is a heat-dissipating surface with a plurality of parallel heat-dissipating fins, and the heat-dissipating cooling plate for heat-pipe-type cooling system with a heat pipe attached to it. A heat pipe having a concave groove for burying a heat pipe in parallel with the heat radiating fin, and a crimping small side provided at a groove edge of the concave groove. Cooling plate for pipe type cooling device.  10. The cooling plate for a heat pipe type cooling device according to claim 9, wherein the heat radiating fin, the concave groove, and the small side are integrally formed by extrusion molding.  1 1. A cooling plate with a plurality of heat radiation fins and heat pipe embedding grooves formed parallel to one side is formed, and the unprocessed heat pipe embedding grooves and heat pipe embedding parts after molding are formed. A heat conductive material is interposed between the heat pipe and the heat pipe, and then the groove edge of the heat pipe burying groove is plastically deformed toward the buried heat pipe side to fix the heat pipe to the cooling plate. A method for manufacturing a heat pipe type cooling device.