TWI589830B - Flat heat pipe and method for manufacturing the same - Google Patents

Description

Flat heat pipe and manufacturing method thereof

The invention relates to a heat pipe, in particular to a flat heat pipe.

The working principle of the flat heat pipe is the same as that of the conventional heat pipe. Because it has a larger heat conduction area than the conventional heat pipe and meets the high practical value of “light, thin, short and small”, it is widely used in a large heat dissipation surface. On the electronics.

A conventional flat heat pipe includes a metal casing and a continuous capillary structure attached to the inner surface of the metal casing. The capillary structure encloses a steam passage therein. The flat heat pipe may be sequentially divided into an evaporation section in contact with the heat source and a condensation section extending from the evaporation section along the length direction thereof. The capillary structure includes a first capillary structure at the evaporation section and a second capillary structure at the condensation section. The first capillary structure and the second capillary structure have the same shape and thickness. When the flat heat pipe works, the working liquid in the first capillary structure enters the steam passage due to evaporation by heat, and reaches the condensation section. After the heat is cooled and liquefied, it is attracted by the capillary force and is returned from the second capillary structure to the first capillary structure. In order to quickly return the working liquid at the second capillary structure to the first capillary structure to prevent dry burning of the first capillary structure, it is necessary to ensure that the first capillary structure has a high capillary force and the second capillary structure has a low capillary force. However, since the shape and thickness of the first capillary structure and the second capillary structure are the same, the capillary force is the same everywhere, and the different requirements of the performance of the first capillary structure and the second capillary structure can not be satisfied at the same time, thereby resulting in The heat transfer performance of the flat heat pipe is not good.

In view of the above, it is necessary to provide a flat heat pipe having good heat transfer performance and a method of manufacturing the flat heat pipe.

A flat heat pipe having an evaporation section, a heat transfer section and a condensation section connected in series, the flat heat pipe comprising a casing and a capillary structure attached to the casing, the capillary structure comprising a first capillary structure located in the evaporation section, a second capillary structure coupled to the first capillary structure and extending from the heat transfer section to the condensation section and a third capillary structure coupled to the first capillary structure and the second capillary structure and extending through the evaporation section, the heat transfer section, and the condensation section, The capillary force of the first capillary structure is greater than the capillary force of the third capillary structure.

A method for manufacturing a flat heat pipe having an evaporation section, a heat transfer section and a condensation section which are sequentially connected, comprising the following steps:

Providing a flat housing having an opening at one end;

Providing a mold having a groove, the mold is placed in the casing such that an inner surface of the casing is formed with a groove-shaped second capillary in a longitudinal direction corresponding to a heat transfer section and a condensation section of the heat pipe structure;

Providing a plurality of metal powders, the powder being sintered to form a first capillary structure at an evaporation section of the heat pipe;

Providing a plurality of metal wires, and winding the metal wires to each other to form the third capillary structure, the third capillary structure penetrating through the evaporation section, the heat transfer section and the condensation section, and one end of the third capillary structure is formed at the Formed on the second capillary structure on one capillary structure and opposite the other end;

The housing is then evacuated and injected with a working fluid and a seal, wherein the capillary force of the first capillary structure is greater than the capillary force of the third capillary structure.

Compared with the prior art, when the flat heat pipe is used, the capillary force of the first capillary structure is greater than the capillary force of the third capillary structure, and the working liquid accommodated in the third capillary structure can be quickly pulled under the capillary force. The third capillary structure is reflowed to the first capillary structure to avoid dry burning of the first capillary structure, thereby ensuring the working performance of the flat heat pipe.

As shown in FIGS. 1 to 3, a flat heat pipe 1 according to a first embodiment of the present invention is shown. The flat heat pipe 1 is an elongated pipe body, and sequentially has an evaporation section 11, a heat transfer section 13 and a condensation section 15 which are sequentially connected along the longitudinal direction thereof. The flat heat pipe 1 includes a casing 30, a capillary structure 50 attached to the inner surface of the casing 30, and a working liquid (not shown) housed in the capillary structure 50. The housing 30 is an inner hollow and elongated flat tube body having equal depths and sealed at opposite ends. The housing 30 has a racetrack shape in cross section.

The capillary structure 50 includes a first capillary structure 51 at the evaporation section 11, a second capillary structure 53 connected to the first capillary structure 51 and extending from the heat transfer section 13 to the condensation section 15, and the first capillary structure 51 and The second capillary structure 53 is connected and extends through the evaporation section 11, the heat transfer section 13, and a third capillary structure 55 of the condensation section 15. The capillary force of the second capillary structure 53 is smaller than the capillary force of the first capillary structure 51 and larger than the capillary force of the third capillary structure 55. The porosity of the second capillary structure 53 is greater than the porosity of the first capillary structure 51 and less than the porosity of the third capillary structure 55.

The first capillary structure 51 is a racetrack-shaped annular structure formed by sintering metal powder, and the outer surface thereof is closely attached and covered with the inner surface of the casing 30 corresponding to the evaporation section 11. The second capillary structure 53 is a groove-like capillary structure formed on the inner surface of the heat transfer section 13 and the condensation section 15 of the casing 30, and one end of the evaporation section 11 is connected to the first capillary structure 51. The length of the second capillary structure 53 in the longitudinal direction of the housing 30 is greater than the length of the first capillary structure 51 in the longitudinal direction of the housing 30. The second capillary structure 53 includes a plurality of protruding teeth 531 and a channel 533 between the protruding teeth 531. The width of each of the protruding teeth 531 is smaller than the width of the channel 533.

The third capillary structure 55 is formed in the middle of the housing 30, and is formed by winding a metal wire. The cross section is flat and elliptical, and one end of one surface is attached to the inner surface of the first capillary structure 51, and the opposite one is opposite. One end is attached to the inner surface of the second capillary structure 53 and forms a minute aperture with the second capillary structure 53, and the remaining portion is spaced apart from the first capillary structure 51 and the second capillary structure 53. The sum of the lengths of the first capillary structure 51 and the second capillary structure 53 in the longitudinal direction of the housing 30 is equal to the length of the third capillary structure 55 in the longitudinal direction of the housing 30.

Thus, when the flat heat pipe 1 is in use, since the porosity of the third capillary structure 55 is greater than the porosity of the first capillary structure 51, the working liquid cooled after the heat release at the condensation section 15 can quickly penetrate into the third capillary structure 55, Moreover, since the capillary force of the first capillary structure 51 is greater than the capillary force of the third capillary structure 55, the working liquid accommodated in the third capillary structure 55 can quickly return from the third capillary structure 55 to the first under the traction of the capillary force. A capillary structure 51 thus avoids dry burning of the first capillary structure 51, thereby ensuring the performance of the flat heat pipe 1.

It can be understood that the first capillary structure 51, the second capillary structure 53, and the third capillary structure 55 are not limited to the materials described in the embodiment, as long as the capillary force of the second capillary structure 53 can be satisfied to be smaller than the first capillary. The capillary force of the structure 51 is greater than the capillary force of the third capillary structure 55, and the porosity of the second capillary structure 53 is greater than the porosity of the first capillary structure 51 and smaller than the porosity of the third capillary structure 55.

4 and 5 show a flat heat pipe 1a according to a second embodiment of the present invention. The flat heat pipe 1a is similar in structure to the flat heat pipe 1 of the first embodiment, and the difference is that the second capillary structure 53a is formed. a capillary structure on the inner surface of the housing 30, and the second capillary structure 53a covers the inner surface of the entire housing 30 along the length direction of the housing 30, and the outer surface of the first capillary structure 51a is attached to the first surface The second capillary structure 53a is located on the inner surface of the evaporation section 11a and forms minute pores with the second capillary structure 53a.

A method of manufacturing the flat heat pipe 1 according to the first embodiment, comprising the steps of:

Providing the housing 30 and opening one end of the housing 30;

Providing a mold having a groove, the mold is placed in the casing 30 such that the inner surface of the casing 30 is grooved in the longitudinal direction corresponding to the heat transfer section 13 and the condensation section 15 of the heat pipe. Second capillary structure 53;

Providing a plurality of metal powders, the powder being sintered to form a first capillary structure 51 attached to the evaporation section 11 of the heat pipe corresponding to the inner surface of the casing 30, the particle size of each metal powder being larger than the The width of each channel 533 of the second capillary structure 53;

A plurality of metal wires are provided, and the metal wires are intertwined to form the third capillary structure 55, and the third capillary structure 55 is placed in the middle of the casing 30, and one end surface is sintered at one end. Forming an inner surface of the first capillary structure 51 on the inner surface of the first capillary structure 51 opposite to the other end on the inner surface of the second capillary structure 53;

The housing 30 is then evacuated and injected with a working fluid and a seal.

Thus, the flat heat pipe 1 in the first embodiment is completed.

The method of manufacturing the flat heat pipe 1a of the second embodiment is similar to the method of manufacturing the flat heat pipe 1 of the first embodiment, except that the second capillary structure 53a is covered with the entire casing 30 in the longitudinal direction of the casing 30. The inner surface, the first capillary structure 51a is sintered and formed on the inner surface of the second capillary structure 53a corresponding to the evaporation section 11a of the flat heat pipe 1.

In addition, those skilled in the art can make other changes in the spirit of the present invention. Of course, the changes made in accordance with the spirit of the present invention should be included in the scope of the present invention.

1, 1a. . . Flat heat pipe

11, 11a. . . Evaporation section

13. . . Heat transfer section

15. . . Condensation section

30. . . case

50. . . Capillary structure

51, 51a. . . First capillary structure

53, 53a. . . Second capillary structure

55. . . Third capillary structure

531. . . Convex tooth

533. . . Channel

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a longitudinal cross-sectional view showing a flat heat pipe of a first embodiment of the present invention.

Figure 2 is a transverse cross-sectional view of the evaporation section of the flat heat pipe shown in Figure 1 taken along line II-II.

Figure 3 is a transverse cross-sectional view of the condensation section of the flat heat pipe of Figure 1 taken along line III-III.

Figure 4 is a longitudinal cross-sectional view showing a flat heat pipe of a second embodiment of the present invention.

Figure 5 is a transverse cross-sectional view of the evaporation section of the flat heat pipe shown in Figure 4 taken along line V-V.

1. . . Flat heat pipe

11. . . Evaporation section

13. . . Heat transfer section

15. . . Condensation section

30. . . case

50. . . Capillary structure

51. . . First capillary structure

53. . . Second capillary structure

55. . . Third capillary structure

Claims (10)

A flat heat pipe having an evaporation section, a heat transfer section and a condensation section connected in series, the flat heat pipe comprising a casing and a capillary structure attached to the casing, wherein the capillary structure comprises a section located in the evaporation section a capillary structure, a second capillary structure disposed on the condensation section, and a third capillary structure connected to the first capillary structure and the second capillary structure and extending through the evaporation section, the heat transfer section and the condensation section, the first capillary structure The capillary force is greater than the capillary force of the third capillary structure, and the porosity of the first capillary structure is less than the porosity of the third capillary structure. The flat heat pipe according to claim 1, wherein the capillary force of the second capillary structure is smaller than the capillary force of the first capillary structure and larger than the capillary force of the third capillary structure, and the pore of the second capillary structure The rate is greater than the porosity of the first capillary structure and less than the porosity of the third capillary structure. The flat heat pipe of claim 1, wherein the second capillary structure is connected to the first capillary structure and extends from the heat transfer section to the condensation section, and is disposed on the heat transfer section and the condensation section of the housing. On the inner surface, one end of the third capillary structure is attached to the first capillary structure, and the other end of the third capillary structure is attached to the second capillary structure. The flat heat pipe of claim 3, wherein the first capillary structure is attached to an inner surface of the corresponding evaporation section of the housing, and the second capillary structure is closer to the first capillary structure. One end of the heat transfer section extends. The flat heat pipe according to claim 1, wherein the second capillary structure is connected to the first capillary structure and extends from the evaporation section to the condensation section, and the entire casing is covered in the longitudinal direction of the casing. The inner surface, one end of the third capillary structure is attached to the first capillary structure, and the other end is attached to the second capillary structure. The flat heat pipe of claim 5, wherein the first capillary structure is formed on an inner surface of the second capillary structure corresponding to the evaporation section of the flat heat pipe. The flat heat pipe according to any one of claims 3 to 6, wherein the first capillary structure and the second capillary structure are both annular in cross section, and the third capillary structure is flat oval and located The middle of the housing. A method for manufacturing a flat heat pipe having an evaporation section, a heat transfer section and a condensation section which are sequentially connected, comprising the following steps:
Providing a housing having an opening at one end;
Providing a mold having a groove, the mold is placed in the casing such that an inner surface of the casing forms a second capillary structure in a longitudinal direction corresponding to a heat transfer section and a condensation section of the heat pipe;
Providing a plurality of metal powders, the powder being sintered to form a first capillary structure at an evaporation section of the heat pipe, wherein a capillary force of the first capillary structure is greater than a capillary force of the third capillary structure, the first The porosity of the capillary structure is smaller than the porosity of the third capillary structure;
Providing a plurality of metal wires, and winding the metal wires to each other to form the third capillary structure, the third capillary structure penetrating through the evaporation section, the heat transfer section and the condensation section, and one end of the third capillary structure is formed at the Formed on the second capillary structure on one capillary structure and opposite the other end;
The housing is then evacuated and the working fluid and seal are injected. The method for manufacturing a flat heat pipe according to claim 8, wherein the second capillary structure is a groove-like capillary structure, and includes a plurality of convex teeth and a channel between the convex teeth, each of the convex teeth The width is smaller than the width of the channel. The method for manufacturing a flat heat pipe according to claim 9, wherein each of the metal powder has a larger particle diameter than each of the second capillary structures.