JP6390566B2 - Cooler - Google Patents

Description

  The present invention relates to a cooler that cools a heating element using a refrigerant.

  Patent Document 1 discloses a steam engine having a heating unit that heats the working fluid in a fluid container in which the working fluid is sealed, and a cooling unit that cools the vapor that is heated and vaporized by the heating unit. The steam engine of Patent Document 1 self-excites the working fluid in the fluid container by flowing and displacing the liquid by the expansion pressure of the steam to output mechanical energy and cooling the liquefied steam in the cooling unit. Displace by vibration.

  In the fluid container, a gas chamber is provided on the side opposite to the cooling unit side with respect to the heating unit, and an inert gas is sealed in the gas chamber.

Japanese Patent No. 4411829

  Although the steam engine of patent document 1 outputs mechanical energy as mentioned above, the steam engine like patent document 1 can be utilized for a purpose different from obtaining mechanical energy. . For example, the inventors have said that the heat transfer from the heating part to the cooling part is promoted by the self-excited vibration displacement of the working fluid in the fluid container, so that the heating source of the heating part is configured by a heating element to be cooled. Then, it was thought that the working fluid in a fluid container can be used as a refrigerant | coolant for cooling the heat generating body. That is, it was thought that the steam engine of patent document 1 can be utilized as a cooler for cooling the heating element.

  Here, the inventors start self-excited oscillation of the refrigerant from a low temperature state before the refrigerant is heated in the cooler that displaces the working fluid as the refrigerant as described above in the fluid container. As a result of examining the case, the following was found.

  That is, when starting the self-excited vibration of the refrigerant, first, at the beginning of heating when the refrigerant starts to be heated, the fluid container is filled with the liquid refrigerant including the inside of the heating section. When the temperature of the heating unit rises and reaches the saturation temperature of the refrigerant, the liquid refrigerant boils in the heating unit and the heating unit is filled with the vapor refrigerant. At this time, the gas-liquid interface of the refrigerant moves from the heating unit side to the cooling unit side as the refrigerant evaporates, but the refrigerant part of the relay unit corresponding to the boundary portion between the heating unit and the cooling unit It stays in the part where the saturation temperature is reached. From there, the fluctuation of the gas-liquid interface is amplified and the self-excited vibration of the refrigerant starts. Therefore, it is considered that the self-excited vibration of the refrigerant is more easily started as the temperature gradient with respect to the vibration direction length of the self-excited vibration is larger in the relay unit between the heating unit and the cooling unit.

  However, if the fluid container that encloses the refrigerant is formed of, for example, a uniform material and thickness, the temperature gradient of the relay unit varies depending on the distance between the heating unit and the cooling unit, and the heating The temperature gradient of the relay part becomes smaller as the distance between the part and the cooling part becomes larger. Therefore, depending on the distance between the heating unit and the cooling unit, it is assumed that the temperature of the heating unit excessively increases before the self-excited vibration of the refrigerant starts. That is, when considering that the cooler using the self-excited vibration of the refrigerant is applied to, for example, cooling of an electronic device, the temperature of the element constituting the electronic device is There is a possibility that the heat resistance temperature of the element will be exceeded with an excessive temperature rise of the heating part.

  In view of the above points, the present invention aims to provide a cooler that cools a heating element with self-excited vibration of a refrigerant, and that can improve the startability of the self-excited vibration. To do.

In order to achieve the above object, in the invention of the cooler according to claim 1, the heating part space (14a) into which the refrigerant enters is formed, and the heat of the heating element (121, 122) is transferred to the refrigerant in the heating part space. A heating section (14) for heating and vaporizing the refrigerant by releasing heat to
A cooling unit space (16a) communicating with the heating unit space is formed, and a cooling unit (16) for cooling and liquefying the refrigerant vaporized by the heating unit and flowing into the cooling unit space;
An absorption part space (18a) communicating with the cooling part space is formed, and an absorption part (18) that absorbs volume change due to heating and cooling of the refrigerant by expansion and contraction of the absorption part space;
A relay section (20) disposed between the heating section and the cooling section and having a relay section space (20a) connecting the heating section space and the cooling section space;
The heating part and the cooling part cause the refrigerant to self-excited and vibrate in the space (14a, 16a, 20a) extending from the heating part space to the cooling part space via the relay part space by repeating vaporization and liquefaction.
The relay unit includes a thermal resistance unit (201) having a partially large thermal resistance per unit length in the vibration direction (DRv) of self-excited vibration.

  According to the above-described invention, the relay unit disposed between the heating unit and the cooling unit includes the thermal resistance unit having a partially large thermal resistance per unit length in the vibration direction of the self-excited vibration. Therefore, for example, as compared with a configuration in which the thermal resistance per unit length is uniform even in the thermal resistance portion, it is easy to increase the temperature gradient of the thermal resistance portion during the heat generation of the heating element. Therefore, it is possible to improve the startability of the self-excited vibration of the refrigerant.

  In addition, each code | symbol in the bracket | parenthesis described in a claim and this column is an example which shows a corresponding relationship with the specific content as described in embodiment mentioned later.

It is the figure which showed the temperature distribution of the cooler 10 on the lower side of the whole block diagram while showing the whole structure of the cooler 10 of 1st Embodiment in cross section. It is a whole block diagram which shows the whole structure of the cooler 90 of the comparative example compared with 1st Embodiment in cross section, Comprising: It is a figure equivalent to the figure of FIG. It is the figure which showed the behavior at the time of the self-excited vibration of a refrigerant | coolant starting in the cooler 90 of FIG. 2, and the temperature distribution of the cooler 90 at the time of the start. The temperature difference between the heating surface temperature Th and the cooling surface temperature Tc when the self-excited vibration of the refrigerant is started by changing the heat generation amount Qin of the heating elements 121 and 122 and the relay portion length L1 in the cooler 90 of FIG. It is the figure which showed the experimental result of the experiment which measured (DELTA) T. FIG. 3 is a diagram for explaining the relationship between the length of the relay section length L1 and the temperature gradient ΔTL1 at the relay section 20 using the cooler 90 of FIG. 2, and the relationship between the length of the relay section length L1 and the relay section 20 It is the figure which showed the relationship with temperature gradient (DELTA) TL1. The overall configuration of the cooler 10 of the second embodiment is shown in cross-section, and the temperature distribution of the cooler 10 is shown below the overall configuration diagram, corresponding to FIG. 1 of the first embodiment. It is. The overall configuration of the cooler 10 of the third embodiment is shown in cross-section, and the temperature distribution of the cooler 10 is shown below the overall configuration diagram, corresponding to FIG. 1 of the first embodiment. It is. FIG. 4 is a cross-sectional view of the overall configuration of the cooler 10 of the fourth embodiment, and is a diagram showing the temperature distribution of the cooler 10 on the lower side of the overall configuration diagram, corresponding to FIG. 1 of the first embodiment. It is. It is an enlarged view of the IX part in FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the same or equivalent parts are denoted by the same reference numerals in the drawings.

(First embodiment)
FIG. 1 is a cross-sectional view of the overall configuration of the cooler 10 of the present embodiment, and is a diagram showing the temperature distribution of the cooler 10 below the overall configuration diagram. As shown in the overall configuration diagram of FIG. 1, the cooler 10 includes a heating unit 14, a cooling unit 16, a volume change absorption unit 18, a relay unit 20, and the like. The cooler 10 cools the heating elements 121 and 122 using the refrigerant sealed in the cooler 10. More specifically, the cooler 10 causes the refrigerant sealed in the cooler 10 to self-excitedly vibrate along the refrigerant vibration direction DRv, thereby causing the heating elements 121 and 122 that are heat sources attached to the heating unit 14. Heat is transferred from the heating unit 14 to the cooling unit 16 to radiate heat from the cooling unit 16 to the outside.

  The lower temperature distribution diagram of FIG. 1 is a diagram showing the temperature distribution of the cooler 10 along the refrigerant vibration direction DRv. That is, in the temperature distribution diagram on the lower side of FIG. 1, the horizontal axis represents the position of the refrigerant vibration direction DRv in the cooler 10, and the vertical axis represents the refrigerant container composed of the heating unit 14, the relay unit 20, and the cooling unit 16. Of these, the temperature of the refrigerant contact surface that faces the refrigerant sealing space 32 described later and contacts the refrigerant is shown. The configurations of the horizontal axis and the vertical axis in this temperature distribution diagram are the same in FIGS. 3D, 5C, and FIGS.

  The refrigerant sealed in the cooler 10 is a fluid that is liquid at room temperature and boils in the cooler 10 when heated by the heating elements 121 and 122. The refrigerant vibration direction DRv is the direction in which the refrigerant reciprocates in the self-excited vibration of the refrigerant sealed in the cooler 10, in other words, the vapor refrigerant (that is, the gas refrigerant) and the liquid refrigerant (in the cooler 10). That is, the gas-liquid interface 26 that makes a boundary with the liquid refrigerant) reciprocates.

  The heating elements 121 and 122 generate heat and are members cooled by the cooler 10. Specifically, the heating elements 121 and 122 are semiconductor elements that need to be cooled. An example is an inverter semiconductor element module. In the present embodiment, two heating elements 121 and 122 are provided, and are attached and fixed to the outside of the heating unit 14. The heating elements 121 and 122 have heat transfer surfaces 121a and 122a that transmit heat of the heating elements 121 and 122 to the heating unit 14, respectively.

  A heating part space 14 a is formed inside the heating part 14. Moreover, the heating part space 14a is filled with the refrigerant. Specifically, the heating unit 14 has a bottomed cylindrical shape. One end of the heating unit space 14a on the cooling unit 16 side in the refrigerant vibration direction DRv is open to communicate with the cooling unit space 16a of the cooling unit 16, but the other end of the heating unit space 14a is closed. Has been.

  Moreover, since the heating part 14 plays the role which transmits the heat | fever of the heat generating bodies 121 and 122 to the refrigerant | coolant in the heating part space 14a, it is comprised with the metal with good heat conductivity, such as an aluminum alloy, for example.

  The first heating element 121 of the two heating elements 121 and 122 contacts the outer surface 141 on one side in the refrigerant vibration intersecting direction DRc orthogonal to the refrigerant vibration direction DRv in the heating unit 14 so that heat can be transferred. It has been made. Specifically, the outer surface 141 on one side thereof is in surface contact with the heat transfer surface 121 a of the first heating element 121.

  Similarly, the second heating element 122 of the two heating elements 121 and 122 is brought into contact with the outer surface 142 on the other side in the refrigerant vibration crossing direction DRc of the heating unit 14 so that heat can be transferred. Yes. Specifically, the outer surface 142 on the other side is in surface contact with the heat transfer surface 122 a of the second heating element 122. Since the heating elements 121 and 122 are attached to the heating unit 14 in this way, the heating unit 14 dissipates the heat of the heating elements 121 and 122 to the refrigerant in the heating unit space 14a and releases heat to the refrigerant. The refrigerant is heated and evaporated.

  In order to improve the heat transfer from the heating elements 121 and 122 to the heating unit 14, the heat transfer surfaces 121a and 122a of the heating elements 121 and 122 are interposed with grease applied to the heat transfer surfaces 121a and 122a. The outer surfaces 141 and 142 of the heating unit 14 may be in contact with each other.

  Inside the cooling part 16, a cooling part space 16a communicating with the heating part space 14a is formed. The cooling unit 16 cools and liquefies the gaseous refrigerant that has been vaporized by the heating unit 14 and has flowed into the cooling unit space 16a, that is, vapor refrigerant. Specifically, the cooling unit 16 includes a cooling unit wall 161 and a cooling device 162. The cooling unit 16 is arranged with the relay unit 20 sandwiched between the heating unit 14 and the refrigerant vibration direction DRv.

  The cooling part wall 161 has a cylindrical shape, and a cooling part space 16a is formed inside thereof. The cooling device 162 includes a plurality of cooling fins 162 a that are formed integrally with the cooling unit wall 161 and are provided around the cooling unit wall 161. And the cooling device 162 cools the refrigerant | coolant in the cooling part space 16a by heat-exchanging with the external air which is the air of the cooler 10 exterior.

  The cooling unit wall 161 and the cooling device 162 are made of a metal having good thermal conductivity such as an aluminum alloy so that high heat radiation performance can be obtained in the cooling unit 16. And the cooling part wall 161 is formed thinly.

  The cooling unit space 16a is a space elongated in the refrigerant vibration direction DRv, and is configured by a pipe having a very small pipe cross-sectional area perpendicular to the refrigerant vibration direction DRv. Therefore, when the refrigerant gas-liquid interface 26 exists in the cooling unit space 16a, the gas-liquid interface 26 faces the heating unit 14 side in the refrigerant vibration direction DRv by the surface tension of the refrigerant regardless of the gravity direction. To be maintained. In the refrigerant vibration direction DRv, the vapor refrigerant exists on the heating unit 14 side with the gas-liquid interface 26 as a boundary, and the liquid refrigerant exists on the opposite side.

  For example, the gas-liquid interface 26 moves away from the heating section space 14a in the cooling section space 16a, that is, the left direction in FIG. Move to. Then, the cooling unit 16 also cools the liquid refrigerant, but also cools and condenses the vapor refrigerant vaporized by the heating unit 14.

  The relay unit 20 is disposed between the heating unit 14 and the cooling unit 16 in the refrigerant vibration direction DRv. Specifically, the relay part 20 has a cylindrical shape extending in the refrigerant vibration direction DRv. One end of the relay unit 20 in the refrigerant vibration direction DRv is connected to the cooling unit wall 161 of the cooling unit 16, and the other end of the relay unit 20 is connected to the heating unit 14. That is, a relay part space 20 a that connects the heating part space 14 a and the cooling part space 16 a is formed inside the relay part 20.

  Similar to the cooling part space 16a, the relay part space 20a is also constituted by a pipe line having a very small pipe cross-sectional area. Therefore, when the refrigerant gas-liquid interface 26 exists in the relay space 20a, the gas-liquid interface 26 faces the heating unit 14 side in the refrigerant vibration direction DRv by the surface tension of the refrigerant regardless of the gravity direction. To be maintained.

  Further, the relay unit 20 includes a thermal resistance unit 201, a heating unit side connection unit 202, and a cooling unit side connection unit 203. The thermal resistance part 201, the heating part side connection part 202, and the cooling part side connection part 203 are connected in series along the refrigerant vibration direction DRv, and from the heating part 14 side to the heating part side connection part 202, the thermal resistance part 201, It arranges in order of the cooling part side connection part 203.

  The heating unit side connection unit 202 is connected to the heating unit 14 and is integrated with the heating unit 14. The cooling unit side connection unit 203 is connected to the cooling unit 16 and is integrated with the cooling unit 16. Therefore, the heating unit 14, the heating unit side connection unit 202, the thermal resistance unit 201, the cooling unit side connection unit 203, the cooling unit 16, and the volume change absorption unit 18 are the heating unit 14, the heating unit side connection unit 202, and the thermal resistance. The part 201, the cooling part side connection part 203, the cooling part 16, and the volume change absorption part 18 are arranged in series along the refrigerant vibration direction DRv in this order.

  Moreover, the heating part side connection part 202 is comprised with the material same as the heating part 14, for example, and the cooling part side connection part 203 is comprised with the material same as the cooling part 16. FIG.

  The thermal resistance part 201 has a ring shape that forms a part of the relay part space 20a inside thereof. Therefore, the inner peripheral surface 201a of the thermal resistance portion 201 is in direct contact with the refrigerant.

  Further, the length of the heat resistance portion 201 in the refrigerant vibration direction DRv is much shorter than the length of the heating portion 14 and the length of the cooling portion 16. That is, the thermal resistance part 201 is locally provided in the refrigerant vibration direction DRv.

  The thermal resistance part 201 is a part where the heating part side connection part 202 and the cooling part side connection part 203 are brazed. In other words, the heating part side connection part 202 and the cooling part side connection part 203 are joint portions that are joined adjacent to the thermal resistance part 201. The thermal resistance unit 201 is made of a brazing material having a lower thermal conductivity than the heating unit side connection unit 202 and the cooling unit side connection unit 203. As a constituent material of the thermal resistance part 201, metal materials, such as an aluminum silicon alloy, can be illustrated.

  Since the thermal resistance portion 201 is made of such a low thermal conductivity material, the thermal resistance portion 201 has a partial thermal resistance RLt per unit length in the refrigerant vibration direction DRv, that is, the unit length thermal resistance RLt. Big. Specifically, the thermal resistance of the thermal resistance unit 201 is lower than the thermal conductivity of the heating unit side connection unit 202 and the cooling unit side connection unit 203. The resistance RLt is locally large.

  More specifically, the unit length thermal resistance RLt is partially larger in the thermal resistance portion 201. Specifically, the thermal resistance portion 201 in the thermal resistance portion 201 is compared with the heating portion side connection portion 202 and the cooling portion side connection portion 203. The unit length thermal resistance RLt is large.

  Thermal resistance is the difficulty in transmitting heat, and the greater the thermal resistance, the less difficult it is to transmit heat. And said unit length thermal resistance RLt is derived | led-out by the following formula F1. Therefore, the unit of the unit length thermal resistance RLt is, for example, “K / (Wm)”.

この式Ｆ１から判るように、熱抵抗部２０１の熱伝導率が低いほど、熱抵抗部２０１の単位長さ熱抵抗ＲＬｔは大きくなる。

As can be seen from the formula F1, the lower the thermal conductivity of the thermal resistance unit 201, the larger the unit length thermal resistance RLt of the thermal resistance unit 201.

  Here, in the formula F1, R is the thermal resistance of the thermal resistance unit 201, L is the length of the thermal resistance unit 201 in the refrigerant vibration direction DRv, and k is the thermal conductivity of the thermal resistance unit 201. . A is a cross-sectional area of the heat resistance portion 201, that is, a heat transfer area. Since the cross section having the cross-sectional area A is a surface facing the heat conduction direction from the heating unit side connection unit 202 to the cooling unit side connection unit 203, in this embodiment, the cross section is an annular surface facing the refrigerant vibration direction DRv. Become. Further, the heat transfer area of the heat resistance part 201 is, in detail, the heat transfer area when the heat resistance part 201 conducts heat from the heating part side connection part 202 to the cooling part side connection part 203. .

  Moreover, since the heating part side connection part 202 and the cooling part side connection part 203 are joined by the thermal resistance part 201, the heating part 14, the relay part 20, and the cooling part 16 are integrated to accommodate the refrigerant. This constitutes one refrigerant container.

  The volume change absorption unit 18 is composed of an elastic member that expands and contracts in a uniaxial direction or a substantially uniaxial direction, and functions as an absorption unit that absorbs the volume change of the refrigerant sealed in the cooler 10. In the present embodiment, the uniaxial direction that is the expansion / contraction direction of the volume change absorbing portion 18 is the same as the refrigerant vibration direction DRv. The volume change absorption unit 18 is configured to be extendable and contractible by, for example, a bellows or a bellows.

  Specifically, an absorption portion space 18a is formed inside the volume change absorption portion 18, and the absorption portion space 18a is an end portion on the opposite side to the heating portion 14 side of the cooling portion space 16a in the refrigerant vibration direction DRv. Communicating with And the volume change absorption part 18 absorbs the volume change by the heating and cooling of a refrigerant | coolant by expansion and contraction of the absorption part space 18a.

  The connection end 18 b that is the end on the cooling unit 16 side of the volume change absorption unit 18 is airtightly fixed to the end of the cooling unit 16 on the side opposite to the heating unit 14 side. Further, the end of the volume change absorbing portion 18 opposite to the connection end 18b is a closed end 18c. Therefore, the absorption part space 18a, the heating part space 14a, the relay part space 20a, and the cooling part space 16a as a whole constitute an airtight refrigerant enclosure space 32 as one space in which refrigerant is enclosed. In other words, the heating unit 14, the relay unit 20, the cooling unit 16, and the volume change absorption unit 18 constitute a refrigerant enclosure in which a refrigerant enclosure space 32 is formed as a whole.

  And the refrigerant | coolant enclosure space 32 is always filled with the refrigerant | coolant. Further, the absorption space 18a is always filled with the liquid refrigerant, for example, even during self-excited vibration of the refrigerant.

  For example, when the refrigerant in the cooling unit space 16a flows into the absorption unit space 18a, the absorption unit space 18a extends and the closed end 18c of the volume change absorption unit 18 moves to the side away from the cooling unit 16 in the refrigerant vibration direction DRv. . Conversely, when the absorbing portion space 18a contracts and the closed end 18c of the volume change absorbing portion 18 moves toward the cooling portion 16 in the refrigerant vibration direction DRv, the refrigerant in the absorbing portion space 18a flows out into the cooling portion space 16a. To do. The volume change absorption unit 18 configured as described above is a drive unit that performs a mechanical operation in the cooler 10.

  Next, the self-excited vibration of the refrigerant performed in the cooler 10 will be described with reference to FIG. In the cooler 10 configured as described above, when the liquid refrigerant in the heating unit space 14a is heated and boiled by the heat of the heating elements 121 and 122, the gas portion of the refrigerant increases. At the same time, the volume of the entire refrigerant increases, so that the absorbing portion space 18a of the volume change absorbing portion 18 expands and the closed end 18c moves to the side away from the cooling portion 16.

  When the gas part of the refrigerant increases to some extent, for example, when the gas-liquid interface 26 passes through the relay part space 20a and enters the cooling part space 16a, the cooling part 16 cools and condenses the refrigerant gas part. When the gas portion is reduced by condensing the gas portion of the refrigerant, the volume of the entire refrigerant is reduced with it. Then, the absorption space 18a of the volume change absorption section 18 contracts and the closed end 18c moves to the side closer to the cooling section 16, and the condensed liquid refrigerant passes from the cooling section space 16a through the relay section space 20a to the heating section space 14a. It flows to. And the liquid refrigerant which flowed into the heating part space 14a is again heated and boiled by the heat of the heating elements 121 and 122 in the heating part 14.

  Thus, in the cooler 10, the heating unit 14 and the cooling unit 16 cause the gas-liquid interface 26 of the refrigerant to self-oscillate in the refrigerant enclosure space 32 by causing the refrigerant to repeat evaporation and condensation. In short, the refrigerant is self-excited and vibrated in the spaces 14a, 16a, and 20a extending from the heating unit space 14a to the cooling unit space 16a.

  And the volume change absorption part 18 absorbs the volume change of the whole refrigerant | coolant accompanying the self-excited vibration of the refrigerant | coolant. Furthermore, since the volume change absorption unit 18 has a predetermined spring constant, a reaction force corresponding to the expansion / contraction amount is generated toward the balance point in the expansion / contraction direction of the volume change absorption unit 18 and the self-excited vibration of the refrigerant is generated. Play a supporting role.

  By repeating the self-excited vibration of the gas-liquid interface 26, that is, the self-excited vibration of the refrigerant, the refrigerant repeatedly evaporates and condenses, thereby obtaining high heat transfer performance in the heat transfer path from the heating elements 121 and 122 to the outside air through the refrigerant. be able to.

  Moreover, in the cooling part space 16a and the absorption part space 18a, the refrigerant is saturated near the gas-liquid interface 26, but the liquid refrigerant in a part away from the gas-liquid interface 26 is in a subcooled state. Therefore, since the liquid refrigerant in the subcooled state contracts the volume change absorption unit 18 and flows into the heating unit space 14a, high cooling performance for cooling the heating elements 121 and 122 can be obtained.

  As described above, according to the present embodiment, the relay unit 20 disposed between the heating unit 14 and the cooling unit 16 includes the thermal resistance unit 201 having a partially large unit length thermal resistance RLt. Yes. Thereby, for example, compared with the configuration in which the unit length thermal resistance RLt is uniform even in the thermal resistance unit 201 in the relay unit 20, the refrigerant vibration direction of the thermal resistance unit 201 during the heat generation of the heating elements 121 and 122 is increased. It is easy to increase the temperature gradient with respect to the DRv length. Therefore, it is possible to improve the startability of the self-excited vibration of the refrigerant in the cooler 10.

  For example, since the thermal resistance unit 201 is provided between the heating unit 14 and the cooling unit 16, minute fluctuations of the gas-liquid interface 26 of the refrigerant are easily amplified at the beginning of heat generation of the heating elements 121 and 122. Therefore, it is possible to reliably start the self-excited vibration of the refrigerant regardless of the interval between the heating unit 14 and the cooling unit 16.

  Here, as the heat resistance of the heating unit 14 increases, the heating performance of the heating unit 14 that transfers the heat of the heating elements 121 and 122 to the refrigerant to heat the refrigerant decreases. Further, as the thermal resistance of the cooling unit 16 increases, the cooling performance of the cooling unit 16 that dissipates heat from the refrigerant and cools the refrigerant decreases. Therefore, in detail about the effect by providing the thermal resistance unit 201, the startability of the self-excited vibration of the refrigerant is improved so that the heating performance of the heating unit 14 and the cooling performance of the cooling unit 16 are not impaired. Is possible.

  In order to clarify the relationship between the unit length thermal resistance RLt of the thermal resistance portion 201 and the startability of the self-excited vibration of the refrigerant, the self-excited vibration of the refrigerant is obtained using a cooler 90 as a comparative example shown in FIG. The behavior when starting will be described. FIG. 2 is an overall configuration diagram showing a cross-sectional view of the overall configuration of the cooler 90 of the comparative example, and corresponds to the upper diagram of FIG. 1.

  The cooler 90 of the comparative example shown in FIG. 2 does not include the thermal resistance unit 201 shown in FIG. 1, and is the same as the cooler 10 of this embodiment except for this point. Therefore, in FIG. 2, the same code | symbol as FIG. 1 is attached | subjected to the part which is common in the cooler 10 of this embodiment among the coolers 90. In FIG. Further, the heating unit 14, the cooling unit 16, and the relay unit 20 of the cooler 90 of FIG. 2 are integrally formed of the same material, and for example, the heating performance of the heating unit 14 and the cooling performance of the cooling unit 16 are impaired. It is made of a metal material with high thermal conductivity so that there is no such thing.

  And the behavior when the self-excited vibration of the refrigerant starts in the cooler 90 of FIG. 2 will be described with reference to FIG. FIG. 3 shows the behavior when the self-excited vibration of the refrigerant starts in the cooler 90 of FIG. 2 and also shows the temperature distribution of the cooler 90 at the time of starting. FIG. 3A shows a stop state in which the heating elements 121 and 122 are not generating heat and the self-excited vibration of the refrigerant is stopped. FIG. 3B shows a state in which the heating elements 121 and 122 start to generate heat and the heating surface temperature Th of the heating unit 14 reaches the saturation temperature Tsat of the refrigerant. FIG. 3C shows a starting state in which the self-excited vibration of the refrigerant is started. Moreover, FIG.3 (d) is the figure which showed the temperature distribution of the cooler 90 in each state of Fig.3 (a)-(c).

  First, as shown in FIG. 3A, when the heating elements 121 and 122 are not generating heat, the self-excited vibration of the refrigerant does not occur, and the refrigerant enclosure space 32 is filled with the liquid refrigerant. The temperature distribution in the refrigerant vibration direction DRv at this time is as indicated by a solid line La in FIG. That is, the heating surface temperature Th is the same as the cooling surface temperature Tc, and is lower than the refrigerant saturation temperature Tsat. The heating surface temperature Th is the temperature Th of the heating surface 143 of the heating unit 14 that faces the heating unit space 14a and contacts the refrigerant. The cooling surface temperature Tc is the temperature Tc of the cooling surface 163 that faces the cooling unit space 16a and contacts the refrigerant in the cooling unit 16.

  Next, when the heating elements 121 and 122 start to generate heat, the refrigerant temperature rises. Then, when the heating surface temperature Th reaches the refrigerant saturation temperature Tsat, the evaporation of the refrigerant proceeds, and as shown in FIG. 3B, the refrigerant gas-liquid interface 26 enters between the heating part space 14a and the relay part space 20a. Moving. The temperature distribution in the refrigerant vibration direction DRv at this time is as shown by the solid line Lb in FIG. That is, the cooling surface temperature Tc remains lower than the refrigerant saturation temperature Tsat, but the heating surface temperature Th coincides with the refrigerant saturation temperature Tsat. Therefore, the inner surface 204 of the relay unit 20 facing the relay unit space 20a is connected to the heating surface 143 on the inner surface 204, that is, at the gas-liquid interface position in contact with the gas-liquid interface 26 of the refrigerant. It is Tsat.

  When the heating surface temperature Th further increases, the temperature distribution of the cooler 90 becomes as indicated by the solid line Lc in FIG. That is, the temperature gradient ΔTL1 of the inner surface 204 of the relay unit 20 increases as the heating surface temperature Th increases. The temperature gradient ΔTL1 exceeds a predetermined threshold at the gas-liquid interface position shown in FIG. As a result, minute fluctuations are amplified at the gas-liquid interface 26 of the refrigerant, and self-excited vibration of the refrigerant is started by amplification of the minute fluctuations as indicated by an arrow V1 in FIG.

  Note that the temperature gradient ΔTL1 of the inner surface 204 of the relay unit 20 is a temperature difference per unit length in the refrigerant vibration direction DRv. That is, in the cooler 90, the temperature gradient ΔTL1 of the inner surface 204 is uniform over the entire length of the inner surface 204 in the refrigerant vibration direction DRv because the relay unit 20 is configured with a uniform material and a uniform thickness. The temperature gradient ΔTL1 of the inner surface 204 is determined by the length L1 of the relay unit 20 in the refrigerant vibration direction DRv (that is, the relay unit length L1), the heating surface temperature Th and the cooling surface temperature Tc calculated from the following formula F2. Is calculated from the following formula F3.

ΔT = Th−Tc (F2)
ΔTL1 = ΔT / L1 (F3)
Here, the relationship between the temperature gradient ΔTL1 and the startability of the self-excited vibration of the refrigerant will be described.

  Although the refrigerant basically has a saturation temperature Tsat at the gas-liquid interface 26, the refrigerant temperature is non-uniform when viewed finely, and local evaporation and condensation of the refrigerant occur due to the non-uniform refrigerant temperature. By this local evaporation and condensation, minute fluctuations, that is, minute displacements of the gas-liquid interface 26 occur.

  In FIG. 3C, assuming that the gas-liquid interface 26 is slightly displaced in one direction of the refrigerant vibration direction DRv, the temperature of the inner surface 204 at the position of the gas-liquid interface before the minute displacement and the gas-liquid interface after the minute displacement are assumed. The difference between the position and the temperature of the inner surface 204 increases as the temperature gradient ΔTL1 of the inner surface 204 increases. And the pressure change of the refrigerant | coolant by the evaporation and condensation of the refrigerant | coolant resulting from the micro displacement of the gas-liquid interface 26 also becomes so large that the temperature gradient (DELTA) TL1 is large. Therefore, as the temperature gradient ΔTL1 is larger, the minute displacement of the gas-liquid interface 26 is more easily amplified, and the self-excited vibration of the refrigerant is more easily started. The behavior when the self-excited vibration of the refrigerant described with reference to FIGS. 3A to 3D starts is the same in the cooler 10 of the present embodiment.

  Considering this point, when looking at the cooler 10 of the present embodiment, the relay unit 20 between the heating unit 14 and the cooling unit 16 has a thermal resistance unit 201 as shown in FIG. This makes it difficult for heat to be conducted from the heating part side connection part 202 to the cooling part side connection part 203. Therefore, as shown in the temperature distribution diagram on the lower side of FIG. The gradient ΔTL1 is partially increased at the position of the thermal resistance portion 201 in the refrigerant vibration direction DRv. Therefore, when the evaporation of the refrigerant proceeds in the heating portion space 14a and moves until the gas-liquid interface 26 comes into contact with the thermal resistance portion 201, a minute displacement of the gas-liquid interface 26 is easily amplified, and the self-excited vibration of the refrigerant is caused as described above. It becomes easy to start.

  Next, the experimental results shown in FIG. 4 will be described. 4 measures the temperature difference ΔT between the heating surface temperature Th and the cooling surface temperature Tc when the self-excited vibration of the refrigerant is started by changing the heat generation amount Qin of the heating elements 121 and 122 and the relay portion length L1. The experimental results are shown. More specifically, when the self-excited vibration of the refrigerant is started, the refrigerant-gas interface 26 starts reciprocating motion between the heating unit space 14a and the cooling unit space 16a. In FIG. 4, the amount of heat generated Qin of the heating elements 121 and 122 is shown on the horizontal axis, and the temperature gradient ΔTL1 when the self-excited vibration of the refrigerant is started is shown on the vertical axis. The temperature gradient ΔTL1 on the vertical axis is calculated from the above formula F3. In the experiment of FIG. 4, the cooler 90 of the comparative example shown in FIG. 2 was used.

  As can be seen from the experimental results in FIG. 4, the temperature gradient ΔTL1 when the self-excited vibration of the refrigerant starts is substantially constant regardless of the relay portion length L1 and the heat generation amount Qin of the heating elements 121 and 122. ing. From this, in order to start the self-excited vibration of the refrigerant, it is considered that the temperature gradient ΔTL1 at the position where the gas-liquid interface 26 contacts the inner surface 204 of the relay unit 20 needs to exceed a predetermined threshold. This also applies to this embodiment. In the coolers 10 and 90 configured to cool the heating elements 121 and 122 by the self-excited vibration of the refrigerant, whether or not the self-excited vibration of the refrigerant starts is determined by the temperature gradient ΔTL1 at the gas-liquid interface position of the refrigerant.

  In the present embodiment, the temperature gradient ΔTL1 in the thermal resistance unit 201 of FIG. 1 is shown as the gradient of the solid line Dt described in the temperature distribution diagram on the lower side of FIG. RLt is determined so that the temperature gradient ΔTL1 at the thermal resistance portion 201 sufficiently exceeds the predetermined threshold.

  Next, the relationship between the length of the relay portion length L1 and the temperature gradient ΔTL1 at the relay portion 20 will be described using the cooler 90 of the comparative example shown in FIG. FIG. 5 is a diagram showing the relationship between the length of the relay portion length L1 and the temperature gradient ΔTL1 at the relay portion 20. As shown in FIG. FIG. 5A is a diagram showing the overall configuration of the cooler 90 having a short relay portion length L1, and FIG. 5B has a longer relay portion length L1 than that of FIG. 5A. FIG. 3 is a diagram showing an overall configuration of a cooler 90. FIG. 5C is a diagram showing a temperature distribution along the refrigerant vibration direction DRv in each cooler 90 of FIGS. 5A and 5B. A solid line L2a in FIG. 5C indicates the temperature distribution in the cooler 90 in FIG. 5A, and a solid line L2b in FIG. 5C indicates the temperature distribution in the cooler 90 in FIG. 5B. Yes. In addition, Tlim of FIG.5 (c) is heating surface temperature Th when the element contained in the heat generating bodies 121 and 122 becomes predetermined heat-resistant temperature.

  As shown in FIG. 5C, the cooler 90 of FIG. 5A and the cooler 90 of FIG. 5B have the same heating surface temperature Th between them, and the cooling surface temperature Tc is also the same. When the same comparison is made, the temperature gradient ΔTL1 in the relay unit 20 in the cooler 90 of FIG. 5B is smaller than the temperature gradient ΔTL1 in the cooler 90 of FIG.

  Therefore, for example, even if the heating surface temperature Th rises to the same temperature by the cooler 90 of FIGS. 5A and 5B, the temperature of the cooler 90 of FIG. When the relay portion length L1 becomes longer, the temperature gradient ΔTL1 at the position of the refrigerant gas-liquid interface 26 (that is, the gas-liquid interface position) becomes smaller in the cooler 90 of FIG. Therefore, even if the self-excited vibration of the refrigerant can be started in the cooler 90 of FIG. 5A, the self-excited vibration of the refrigerant may not be started in the cooler 90 of FIG. 5B.

  5C, in order to obtain the same temperature gradient ΔTL1 in the cooler 90 in FIG. 5B as in the cooler 90 in FIG. 5A, the cooler 90 in FIG. In comparison with the cooler 90, it is necessary to further increase the heating surface temperature Th. If so, there is a possibility that the temperature of the elements included in the heating elements 121 and 122 exceeds the heat-resistant temperature Tlim before the self-excited vibration of the refrigerant is started.

  In contrast, in the cooler 10 of the present embodiment shown in FIG. 1, the unit length thermal resistance RLt of the thermal resistance unit 201 is larger than that of the heating unit side connection unit 202 and the cooling unit side connection unit 203. The thermal resistance portion 201 is locally provided in the refrigerant vibration direction DRv. Therefore, there is an advantage that the temperature gradient ΔTL1 in the thermal resistance portion 201 can be easily increased.

  Moreover, according to this embodiment, the thermal resistance part 201 is comprised with the material whose heat conductivity is low compared with the heating part side connection part 202 and the cooling part side connection part 203. FIG. Thereby, in the thermal resistance part 201, unit length thermal resistance RLt is large compared with the heating part side connection part 202 and the cooling part side connection part 203. FIG. Therefore, it is possible to use the brazing part that joins the heating unit 14 and the cooling unit 16 as the thermal resistance unit 201 that locally increases the unit length thermal resistance RLt.

  In other words, since the heat conduction is poor in the brazing material portion corresponding to the heat resistance portion 201, during the heat generation of the heating elements 121 and 122, the heat resistance portion 201 locally produces heat as shown by the solid line Dt in FIG. A large temperature gradient ΔTL1 is applied. Therefore, minute fluctuations in the gas-liquid interface 26 of the refrigerant are easily amplified, and self-excited vibration of the gas-liquid interface 26 can be reliably started.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. In the present embodiment, differences from the first embodiment will be mainly described. Further, the same or equivalent parts as those of the above-described embodiment will be described by omitting or simplifying them. The same applies to the third and later embodiments described later.

  FIG. 6 is a cross-sectional view of the overall configuration of the cooler 10 of the present embodiment, and is a diagram showing the temperature distribution of the cooler 10 on the lower side of the overall configuration diagram, which is similar to FIG. 1 of the first embodiment. It is an equivalent figure. As shown in FIG. 6, in this embodiment, the thermal resistance portion 201 is different from that of the first embodiment.

  Specifically, the thermal resistance unit 201 of the present embodiment is an O-ring. This O-ring is generally used as a seal member and is made of an elastic body such as rubber. Further, the O-ring as the heat resistance portion 201 has, for example, a substantially circular cross section, and is formed in an annular shape around the relay portion space 20a.

  In the relay unit 20, the heating unit side connection unit 202 and the cooling unit side connection unit 203 are joined by bolts 205 with an O-ring serving as the thermal resistance unit 201 interposed therebetween. The O-ring prevents the refrigerant from leaking out between the heating unit side connection unit 202 and the cooling unit side connection unit 203.

  Moreover, the heating part side connection part 202 and the cooling part side connection part 203 are not in direct contact, and the O-ring as the heat resistance part 201 is connected between the heating part side connection part 202 and the cooling part side connection part 203. They are in direct contact with each other.

  In addition, since the O-ring as the heat resistance unit 201 is made of rubber or the like, for example, the heat conduction of the heat resistance unit 201 in the above formula F1 as compared with the heating unit side connection unit 202 and the cooling unit side connection unit 203. The rate k becomes a low value. Accordingly, in this embodiment as well, as in the first embodiment, the thermal resistance portion 201 is made of a material having a lower thermal conductivity k than the heating portion side connection portion 202 and the cooling portion side connection portion 203. In the thermal resistance portion 201, the unit length thermal resistance RLt is partially increased.

  Furthermore, the contact surface between the O-ring and the heating unit side connection unit 202 and the contact surface between the O-ring and the cooling unit side connection unit 203 are both elongated and linearly extending around the relay unit space 20a. Therefore, the cross-sectional area A of the thermal resistance portion 201 in the formula F1 is also locally reduced. Therefore, in the heat resistance part 201 of this embodiment, the heat transfer area A, which is the area A of the cross section facing the refrigerant vibration direction DRv, is smaller than that of the heating part side connection part 202 and the cooling part side connection part 203. This also partially increases the unit length thermal resistance RLt.

  As described above, since the heat conduction is poor in the heat resistance portion 201 formed of the O-ring, the heat resistance portion 201 locally generates heat during the heat generation of the heating elements 121 and 122 as shown by the solid line Dt in FIG. A large temperature gradient ΔTL1 is generated. Therefore, minute fluctuations in the gas-liquid interface 26 of the refrigerant are easily amplified, and self-excited vibration of the gas-liquid interface 26 can be reliably started.

  In the present embodiment, the effects produced from the configuration common to the first embodiment described above can be obtained as in the first embodiment.

(Third embodiment)
Next, a third embodiment of the present invention will be described. In the present embodiment, differences from the first embodiment will be mainly described.

  FIG. 7 is a cross-sectional view of the overall configuration of the cooler 10 of the present embodiment, and is a diagram showing the temperature distribution of the cooler 10 on the lower side of the overall configuration diagram, which is similar to FIG. 1 of the first embodiment. It is an equivalent figure. As shown in FIG. 7, in this embodiment, the thermal resistance portion 201 is different from that in the first embodiment.

  Specifically, the thermal resistance part 201 of the present embodiment is made of the same material as the heating part side connection part 202 and the cooling part side connection part 203. For example, the thermal resistance unit 201, the heating unit side connection unit 202, the cooling unit side connection unit 203, the heating unit 14, and the cooling unit 16 are made of the same material and are integrally formed.

  However, in the thermal resistance part 201 of the present embodiment, the thickness is formed thinner than the heating part side connection part 202 and the cooling part side connection part 203. That is, the thickness of the relay part 20 is partially reduced by the heat resistance part 201. More specifically, the thickness of the heat resistance portion 201 is locally reduced.

  That is, in the thermal resistance part 201, the cross-sectional area A in the formula F1 is locally small. Therefore, in the heat resistance part 201 of this embodiment, the heat transfer area A, which is the area A of the cross section facing the refrigerant vibration direction DRv, is smaller than that of the heating part side connection part 202 and the cooling part side connection part 203. As a result, the unit length thermal resistance RLt is partially increased.

  Since heat conduction is poor in the heat resistance portion 201 having a large unit length thermal resistance RLt in this way, during heat generation of the heat generating elements 121 and 122, the heat resistance portion 201 is shown as a gradient of the solid line Dt in FIG. A large temperature gradient ΔTL1 is locally produced. Therefore, minute fluctuations in the gas-liquid interface 26 of the refrigerant are easily amplified, and self-excited vibration of the gas-liquid interface 26 can be reliably started.

  In the present embodiment, the effects produced from the configuration common to the first embodiment described above can be obtained as in the first embodiment.

  Further, as described above, according to the present embodiment, in the thermal resistance portion 201, the area A of the cross section facing the refrigerant vibration direction DRv is smaller than that of the heating portion side connection portion 202 and the cooling portion side connection portion 203. As a result, the unit length thermal resistance RLt is partially increased. Therefore, the unit length thermal resistance RLt can be partially increased depending on the shape of the thermal resistance portion 201. For example, there is an advantage that it is not necessary to configure the thermal resistance part 201 with a material different from that of the heating part side connection part 202 and the cooling part side connection part 203.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described. In the present embodiment, differences from the first embodiment will be mainly described.

  FIG. 8 is a cross-sectional view of the overall configuration of the cooler 10 of the present embodiment, and shows the temperature distribution of the cooler 10 on the lower side of the overall configuration diagram, and is shown in FIG. 1 of the first embodiment. It is an equivalent figure. As shown in FIG. 8, in this embodiment, the thermal resistance portion 201 is different from that of the first embodiment.

  Specifically, in the present embodiment, the heating part side connection part 202 and the cooling part side connection part 203 are joined by a bolt 205. That is, in the bolting by the bolt 205, the contact surface 202a facing the cooling unit side connection unit 203 side of the heating unit side connection unit 202 and the heating unit side connection unit 202 of the cooling unit side connection unit 203 in the refrigerant vibration direction DRv. The contact surfaces 203a facing toward each other are in direct contact with each other. In the present embodiment, the two contact surfaces 202a and 203a constitute the thermal resistance unit 201.

  As described above in the description of the first embodiment, since the heating part side connection part 202 and the cooling part side connection part 203 are made of a metal material such as an aluminum alloy, the two contact surfaces 202a and 203a are formed of the bolt 205. The metal is in contact with each other while being pressed by the fastening force. Further, as shown in FIG. 9 in which the IX portion in FIG. 8 is enlarged, any of the contact surfaces 202a and 203a has surface roughness. Therefore, when viewed in detail, there are many direct contacts between the two contact surfaces 202a and 203a. It consists of point contact.

  Due to such a configuration of the thermal resistance portion 201, the heat transfer area of the thermal resistance portion 201 formed by a number of point contacts between the contact surfaces 202a and 203a corresponds to the cross-sectional area A of the thermal resistance portion 201 in the above formula F1. And since the heat transfer area of the heat resistance part 201 is the magnitude | size which brought together the contact area of many point contacts, the heat transfer area of the heat resistance part 201 is locally small.

  Therefore, in the thermal resistance part 201 of the present embodiment, the heat transfer area A, which is the cross-sectional area A of the thermal resistance part 201 in Formula F1, is smaller than that of the heating part side connection part 202 and the cooling part side connection part 203. As a result, the unit length thermal resistance RLt is partially increased.

  As described above, since the thermal resistance locally increases in the thermal resistance portion 201 due to the metal contact, during the heat generation of the heating elements 121 and 122 in FIG. 8, the thermal resistance is shown as the gradient of the solid line Dt in FIG. 8. The part 201 has a large temperature gradient ΔTL1 locally. Therefore, minute fluctuations in the gas-liquid interface 26 of the refrigerant are easily amplified, and self-excited vibration of the gas-liquid interface 26 can be reliably started.

  In the present embodiment, the effects produced from the configuration common to the first embodiment described above can be obtained as in the first embodiment.

(Other embodiments)
(1) In the first embodiment described above, the heating part side connection part 202 and the cooling part side connection part 203 are joint parts joined to the thermal resistance part 201, but the heating part side connection part 202 and the cooling part side. There may be no connection part 203, and the heating part 14 and the cooling part 16 may be directly joined to the thermal resistance part 201. In that case, the part on the heat resistance part 201 side in the heating part 14 and the part on the heat resistance part 201 side in the cooling part 16 correspond to the joining parts to be joined to the heat resistance part 201, respectively. The same applies to the second to fourth embodiments.

  (2) In each of the above-described embodiments, two heating elements 121 and 122 are provided, but one or three or more heating elements 121 and 122 may be provided.

  (3) In each of the embodiments described above, the heating elements 121 and 122 are semiconductor elements or the like that need to be cooled, but need not be electrical components.

  (4) In each of the above-described embodiments, the heating elements 121 and 122 are attached to the outside of the heating unit 14, but may be accommodated in the heating unit space 14a and arranged so that the refrigerant is in direct contact therewith. There is no problem.

  (5) In each of the above-described embodiments, the cooler 10 has a shape extending in the refrigerant vibration direction DRv. However, the shape of the cooler 10 is not limited. For example, the cooler 10 is described in Patent Document 1. It may be formed in a U shape like a steam engine made.

  (6) In each of the above-described embodiments, the cooling unit 16 cools the refrigerant in the cooling unit space 16a by exchanging heat with the outside air. However, the cooling unit 16 is provided with a pipe through which cooling water flows around the cooling unit 16, The cooling water may be cooled by exchanging heat with the cooling water.

  (7) In each of the above-described embodiments, the volume change absorption unit 18 is configured by a bellows or the like and expands and contracts in the refrigerant vibration direction DRv, but may be configured by, for example, a diaphragm or the like, or expands and contracts the refrigerant. A structure that does not expand and contract is acceptable as long as it can be absorbed.

  (8) In each embodiment described above, the installation direction of the cooler 10 is not particularly limited, but the vertical direction of the cooler 10 may be specified. For example, the cooler 10 may be installed such that the cooling unit space 16a is positioned below the heating unit space 14a.

  In addition, this invention is not limited to above-described embodiment, In the range described in the claim, it can change suitably. In each of the above-described embodiments, it is needless to say that elements constituting the embodiment are not necessarily essential unless explicitly stated as essential and clearly considered essential in principle. Yes. Further, in each of the above embodiments, when numerical values such as the number, numerical value, quantity, range, etc. of the constituent elements of the embodiment are mentioned, it is clearly limited to a specific number when clearly indicated as essential and in principle. The number is not limited to the specific number except for the case. In each of the above embodiments, when referring to the material, shape, positional relationship, etc. of the constituent elements, etc., unless otherwise specified, or in principle limited to a specific material, shape, positional relationship, etc. The material, shape, positional relationship, etc. are not limited.

14 Heating part 14a Heating part space 16 Cooling part 16a Cooling part space 18 Volume change absorption part (absorption part)
18a Absorption part space 20 Relay part 20a Relay part space 121, 122 Heating element 201 Thermal resistance part

Claims (4)

A heating unit space (14a) into which the refrigerant enters is formed, and a heating unit (14) that heats and vaporizes the refrigerant by dissipating heat of the heating elements (121, 122) to the refrigerant in the heating unit space. When,
A cooling unit space (16a) communicating with the heating unit space is formed, and a cooling unit (16) that cools and liquefies the refrigerant that has been vaporized by the heating unit and has flowed into the cooling unit space;
An absorption part space (18a) communicating with the cooling part space is formed, and an absorption part (18) that absorbs volume change due to heating and cooling of the refrigerant by expansion and contraction of the absorption part space;
A relay section (20) disposed between the heating section and the cooling section and having a relay section space (20a) connecting the heating section space and the cooling section space;
The heating unit and the cooling unit cause the refrigerant to repeat vaporization and liquefaction so that the space (14a, 16a, 20a) spans the cooling unit space from the heating unit space through the relay unit space. The self-excited vibration of the refrigerant,
The said relay part has a thermal resistance part (201) with a partially large thermal resistance per unit length in the vibration direction (DRv) of the said self-excited vibration, The cooler characterized by the above-mentioned.   Since the thermal resistance portion is made of a material having a lower thermal conductivity than the joining sites (202, 203) joined to the thermal resistance portion, the thermal resistance portion has a unit length in the vibration direction. The cooler according to claim 1, wherein the perimeter thermal resistance is partially large.   In the thermal resistance part, the area of the cross section facing the vibration direction is smaller than the joining sites (202, 203) joined to the thermal resistance part, so that per unit length in the vibration direction. The cooler according to claim 1, wherein the thermal resistance of the cooler is partially high.   The fact that the thermal resistance per unit length in the vibration direction in the thermal resistance portion is partially large means that the thermal resistance portion in the thermal resistance portion is compared to the joining sites (202, 203) joined to the thermal resistance portion. The cooler according to claim 1, wherein the thermal resistance per unit length is large.

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