CN109520366B

CN109520366B - Thermal switch

Info

Publication number: CN109520366B
Application number: CN201811594683.2A
Authority: CN
Inventors: 赵雅楠; 梁惊涛
Original assignee: Technical Institute of Physics and Chemistry of CAS
Current assignee: Technical Institute of Physics and Chemistry of CAS
Priority date: 2018-12-25
Filing date: 2018-12-25
Publication date: 2024-07-23
Anticipated expiration: 2038-12-25
Also published as: CN109520366A

Abstract

The invention relates to the technical field of refrigeration and low temperature, and discloses a thermal switch, which comprises: the heat source device comprises a moving part, a fixing part and a telescopic part, wherein the moving part is arranged towards the heat source, a cold source is arranged on the fixing part, the telescopic part is arranged between the moving part and the fixing part, two ends of the telescopic part are respectively connected with the moving part and the fixing part, the telescopic part and the moving part and the fixing part form a first cavity jointly, working medium changing along with temperature is filled in the first cavity, the working medium expands or contracts in the first cavity to enable the telescopic part to stretch out and retract, and the telescopic part stretches out and retracts to drive the moving part and the fixing part to perform relative movement, so that the moving part and the heat source are connected and disconnected. The thermal switch has the advantage of a large switching ratio.

Description

Thermal switch

Technical Field

The invention relates to the technical field of refrigeration and low temperature, in particular to a thermal switch.

Background

Currently, thermal switches refer to devices that are capable of controlling the thermal contact or separation between two objects. In the field of refrigeration and cryogenic technology, many applications require that two components be capable of being thermally connected and thermally separated, respectively, under different operating conditions. For example, with the development of the spatial infrared detection technology, a longer service life and reliability are required for the mechanical refrigeration technology, and because of the irreparability of the spatial refrigerator, the spatial refrigerator needs to be backed up in the same system, and in order to reduce or eliminate the parasitic heat leakage of the backup refrigerator in a non-working state, the spatial refrigerator needs to be connected with a cooled device through a thermal switch, and the unidirectional transmission of the cold energy from the refrigerator to the cooled device is realized by utilizing the thermal switch. When the superconducting magnet is cooled at low temperature, a low-temperature refrigerator with a two-stage structure is generally adopted, the superconducting magnet is connected with the second-stage cold head, and the second-stage cold head is small in cooling capacity and low in efficiency, so that the magnet can be cooled from room temperature to the lowest temperature only by a long time, the first-stage cold head of the refrigerator is provided with larger cooling capacity, the first-stage cold head and the magnet can be connected through the thermal switch, when the temperature of the magnet is higher than that of the first-stage cold head, the magnet is precooled through the first-stage cold head, when the temperature of the magnet is lowered to the temperature below the first-stage cold head, the thermal switch is in an off state, and the magnet is continuously cooled through the second-stage cold head, so that the cooling time of the magnet can be greatly shortened.

The common thermal switches mainly comprise mechanical type, gas gap type, shape memory alloy type, micro expansion type, heat pipe type and other types of thermal switches. The mechanical thermal switch has lower reliability and requires external driving force; the gas gap type thermal switch realizes on-off by inflating and exhausting between the two heat conducting sheets, the temperature of the adsorption pump needs to be controlled by utilizing a heating and cooling device, the system is complex, the conduction thermal resistance for realizing communication by utilizing gas heat conduction is larger, and the response time of the thermal switch is greatly influenced by the exhausting speed; the shape memory alloy type thermal switch utilizes temperature change to cause shape change of the memory alloy, drives the cold and hot components to be connected or disconnected, has strict and symmetrical structural requirements, and has high requirements on processing precision; the micro-expansion type thermal switch utilizes different thermal expansion coefficients of different materials, realizes connection or disconnection after temperature change, has high processing precision requirement, is easy to generate cold welding during long-term closing operation, has poor reliability, and needs to have enough length to enable the different materials to directly form larger contraction and expansion differences, and cannot be made into a short structure; the heat pipe type heat switch utilizes the gas-liquid phase change of the working medium to conduct forward efficient heat transfer and reverse disconnection, the response time is long generally, the connection and disconnection temperature is limited by the three-phase temperature of the gas working medium, the heat pipe type heat switch can only be suitable for part of working temperature ranges, the advantage is obvious when the length of the heat pipe type heat switch is large, and the disconnection thermal resistance is small when the length is short.

Disclosure of Invention

First, the technical problem to be solved

The invention aims to provide a thermal switch, which at least solves one of the technical problems of small switching ratio, low reliability, high processing precision requirement and non-compact structure of the thermal switch in the prior art.

(II) technical scheme

In order to solve the above technical problems, the present invention provides a thermal switch, including: the heat source device comprises a moving part, a fixing part and a telescopic part, wherein the moving part is arranged towards the heat source, a cold source is arranged on the fixing part, the telescopic part is arranged between the moving part and the fixing part, two ends of the telescopic part are respectively connected with the moving part and the fixing part, the telescopic part and the moving part and the fixing part form a first cavity jointly, working medium changing along with temperature is filled in the first cavity, the working medium expands or contracts in the first cavity to enable the telescopic part to stretch out and retract, and the telescopic part stretches out and retracts to drive the moving part and the fixing part to perform relative movement, so that the moving part and the heat source are connected and disconnected.

Wherein the moving part and the fixed part are in direct contact connection; or the moving part is connected with the fixed part through the extending part, at least one surface of the moving part is contacted with the fixed part, and the moving part and the fixed part can slide along the contacted surface, so that the moving part and the fixed part can move relatively.

The thermal switch further comprises an extension piece, the extension piece comprises a first extension piece and a second extension piece, the first extension piece is connected with the moving piece, and the second extension piece is connected with the fixing piece.

Wherein the first extension piece and the second extension piece are in plug-in fit.

The lower surface of the moving part is provided with a convex part extending towards the direction of the fixed part, the upper surface of the fixed part is provided with an annular cavity opening towards the moving part, and the convex part is inserted into the annular cavity and can extend and retract relative to the longitudinal direction of the annular cavity.

The movable member is characterized in that a plurality of first convex parts extending towards the direction of the fixed member are formed on the lower surface of the movable member, a plurality of second convex parts extending towards the direction of the movable member are formed on the upper surface of the fixed member, and one second convex part is arranged between every two adjacent first convex parts.

Wherein a closed second cavity is constructed between the first extension piece and the second extension piece, a communication hole is constructed on the side wall of the annular cavity, and the first cavity is communicated with the second cavity through the communication hole; or the communication hole communicates the second chamber with the outside.

The telescopic piece is positioned at the outer side of the annular cavity, and the second cavity is positioned in the first cavity; or the telescopic piece is positioned on the inner side of the annular cavity, and the first cavity is positioned in the second cavity.

The thermal switch further comprises a second fixing piece and a supporting piece, wherein the second fixing piece is arranged above the moving piece, the supporting piece is arranged between the fixing piece and the second fixing piece and is located on the outer side of the telescopic piece, a heat source is installed on the second fixing piece, and the moving piece and the second fixing piece are connected and disconnected through contact and separation between the moving piece and the heat source.

The thermal switch further comprises a third extending piece, the third extending piece comprises an annular portion and a horizontal stop portion, the annular portion is arranged on the lower surface of the second fixing piece and extends towards the direction of the fixing piece, the horizontal stop portion is arranged on the edge of the lower opening of the annular portion and extends towards the central line direction of the annular portion, a first space is formed by the annular portion, the horizontal stop portion and the second fixing piece together, the moving piece is arranged in the first space, the moving piece can reciprocate up and down in the first space along with the first extending piece, and two ends of the moving piece can be lapped on the upper surface of the horizontal stop portion.

(III) beneficial effects

Compared with the prior art, the thermal switch provided by the invention has the following advantages:

Through setting up the heat source on moving the piece, set up the cold source on the mounting, then fill the working medium to first cavity in, utilize the expansion and the shrink of working medium to drive the moving piece and upwards move, the longitudinal displacement volume of this moving piece is great, relies on the heat conduction effect of the contact surface between moving piece and the mounting to transfer heat when the thermal switch switches on, and heat transfer stability is high, and conduction heat transfer resistance is less. When the thermal switch is disconnected, the contact surface between the moving part and the heat source is thoroughly separated, and the disconnection thermal resistance is very large, so that the thermal switch can obtain a very large switching ratio.

Drawings

FIG. 1 is a schematic view showing the overall structure of a thermal switch according to a first embodiment of the present application;

FIG. 2 is a schematic diagram of the overall structure of a thermal switch according to a second embodiment of the present application;

FIG. 3 is a schematic view of the overall structure of a thermal switch according to a third embodiment of the present application;

FIG. 4 is a schematic view showing the overall structure of a thermal switch according to a fourth embodiment of the present application;

FIG. 5 is a schematic view of the overall structure of the insulating support structure of FIG. 4;

fig. 6 is a schematic diagram showing the overall structure of a thermal switch according to a fifth embodiment of the present application.

In the figure, 1: a thermal switch; 11: a moving member; 111: a first extension; 12: a fixing member; 121: a second extension; 13: a telescoping member; 14: a first cavity; 15: a second cavity; 151: a communication hole; 16: a support; 17: a second fixing member; 171: a third extension; 2: a heat source; 3: and a cold source.

Detailed Description

The following describes in further detail the embodiments of the present invention with reference to the drawings and examples. The following examples are illustrative of the invention and are not intended to limit the scope of the invention.

In the description of the present invention, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art.

It should be noted that all the modes related to the up-down and left-right expressions are descriptions about the setting orientations presented by the current schematic diagram.

Fig. 1 shows a schematic structural view of a thermal switch 1 according to a first embodiment of the present invention, including a moving member 11, a fixed member 12, and a telescopic member 13.

In the embodiment of the application, the moving part 11 is arranged towards the heat source 2, the cold source 3 is arranged on the fixed part 12, the telescopic part 13 is arranged between the moving part 11 and the fixed part 12, two ends of the telescopic part 13 are respectively connected with the moving part 11 and the fixed part 12, the telescopic part 13, the moving part 11 and the fixed part 12 form a closed first cavity 14 together, a working medium which changes with temperature is filled in the first cavity 14, the working medium expands or contracts in the first cavity 14 to promote the telescopic part 13 to extend and retract, and the moving part 11 and the fixed part 12 are driven to relatively move through the extending and retracting of the telescopic part 13, so that the moving part 11 is connected and disconnected with the heat source 2. The heat sink 3 may be provided to the movable member 11, and the heat source 2 may be provided to the fixed member 12.

Specifically, the heat source 2 is arranged on the moving part 11, the cold source 3 is arranged on the fixed part 12, then the working medium is filled in the first cavity 14, the expansion and contraction of the working medium are utilized to drive the moving part 11 to move upwards, the longitudinal displacement of the moving part 11 is large, heat transfer is carried out by means of the heat conduction effect of the contact surface between the moving part 11 and the fixed part 12 when the thermal switch 1 is conducted, the heat transfer stability is high, and the conduction heat transfer resistance is small. When the thermal switch 1 is turned off, the contact surface between the moving member 11 and the heat source 2 is thoroughly separated, and the off heat resistance is very large, so that a very large switching ratio of the thermal switch 1 can be obtained.

The moving member 11 and the fixed member 12 may be directly connected, or the moving member 11 or the fixed member 12 may be provided with the extending member 13, or the moving member 11 and the fixed member 12 may be provided with the extending member 13, where the connection with the moving member 11 is defined as a first extending member 111, and the connection with the fixed member 12 is defined as a second extending member 121.

By providing the extension 13, the length of the thermal switch 1 can be extended, facilitating the heat transfer arrangement of the heat source 2 and the heat sink 3 at a relatively large distance.

Further, by appropriately increasing the contact area between the moving member 11 and the fixed member 12, the heat transfer resistance between the moving member 11 and the fixed member 12 can be effectively reduced. The extension 13 also serves to position and prevent the moving member 11 from being displaced or tilted during movement, so that the member with which the moving member 11 is in contact can be better contacted. The moving member 11, the fixing member 12 and the extending member 13 are made of a material with good heat conduction performance, for example, a metal material with high heat conduction coefficient such as red copper, aluminum and the like can be selected.

In this embodiment, the moving member 11 is provided with the first extending member 111, and the fixed member 12 is provided with the second extending member 121, at least one surface contact between the first extending member 111 and the second extending member 121 is provided, and when the moving member 11 and the fixed member 12 move relatively, the first extending member 111 and the second extending member 121 maintain contact with each other, and slide along the contact surface.

In this embodiment, the first extension member 111 may be configured to be cylindrical, the second extension member 121 is configured to be cylindrical, the outer cylindrical surface of the first extension member 111 is tightly matched with the inner cylindrical surface of the second extension member 121, the first extension member 111 can slide freely in the second extension member 121, and heat conduction can be achieved through the cylindrical surfaces of the first extension member 111 and the second extension member 121 contacting each other.

In a preferred embodiment, the first extension 111 and the second extension 121 are interposed between

As shown in fig. 1,2,4 and 6, in one embodiment, a convex portion extending toward the fixed member 12 is formed at the lower surface of the movable member 11, and an annular cavity opening toward the movable member 11 is formed at the upper surface of the fixed member 12, wherein the convex portion is inserted into the annular cavity and is capable of extending and retracting movement with respect to the longitudinal direction of the annular cavity.

As shown in fig. 3, in another embodiment, a plurality of first protrusions extending toward the fixed member 12 are configured on the lower surface of the movable member 11, and a plurality of second protrusions extending toward the movable member 11 are configured on the upper surface of the fixed member 12, wherein one of the second protrusions is disposed between each two adjacent first protrusions.

As shown in fig. 1, a closed second cavity 15 is formed between the first extension member 111 and the second extension member 121, and in this embodiment, a communication hole 151 is provided at the bottom of the second extension member 121 to enable the second cavity 15 to communicate with the first cavity 14, and the second cavity 15 and the first cavity 14 always maintain the same pressure, so that the first extension member 111 and the second extension member 121 slide relatively smoothly. At least one communication hole 151 and/or a communication groove (not shown) may be formed in the first extension member 111 and/or the second extension member 121 to achieve the same or better communication effect.

The working medium filled in the first cavity 14 of the thermal switch 1 is in a gas state or a gas-liquid two-phase state in the working temperature zone, the gas type can be selected according to the requirement of the specific working temperature zone, for example, helium, neon, nitrogen or oxygen can be selected when working in the temperature zone of 80K, helium, neon or the like can be selected when working in the temperature zone of 30K, and the filled gas can be single gas or a mixture of several gases. The pressure of the air to be filled is designed according to the elasticity of the telescopic member 13 and the requirement of the telescopic member 13, so that the thermal switch 1 has proper expansion or contraction in the working process. When the working medium is in a gas-liquid two-phase state in the working temperature area of the thermal switch 1, the liquid working medium can flow back by gravity or capillary action, the liquid evaporates at the position with higher temperature, the generated gas flows to the position with lower temperature to be condensed, and the heat transfer enhancement effect is achieved between the moving part 11 and the fixed part 12 by means of the gas-liquid phase change and the circulating flow of the working medium.

In this embodiment, the thermal switch 1 has a plurality of operation modes, the fixing member 12 may be connected to the heat source 2 or the cold source 3, and the initial state of the telescopic member 13 may be an extended state or a contracted state. For example, the fixing member 12 may be connected to the heat source 2, the thermal switch 1 may be in an extended state in the initial state in the operating temperature range, and the movable member 11 may be brought into contact with the heat sink 3, and at this time, the thermal switch 1 may be in an on state.

After the heat source 2 is cooled down, the volume of the working medium is reduced, the telescopic piece 13 is contracted, the thermal switch 1 is in a contracted state, and the movable piece 11 is separated from the cold source 3, namely, the thermal switch 1 is in an off state. Alternatively, the fixing member 12 may be connected to the heat sink 3, and the thermal switch 1 may be in a contracted state in the initial state in the operating temperature range, so that the movable member 11 is separated from the heat source 2, that is, the thermal switch 1 may be in an off state. When the temperature of the heat source 2 increases, the volume of the working medium increases, and the expansion element 13 expands, so that the movable element 11 contacts the heat source 2, that is, the thermal switch 1 is in an on state.

The expansion member 13 may be a bellows, or may be other structures or materials having an expansion function, such as a tubular or bladder structure made of rubber, or the like.

The working process of the present embodiment will be described below by taking the thermal switch 1 working at a level of Wen Wenou as an example, the first chamber 14 is filled with gas under a certain pressure, the expansion member 13 is in an expanded state at room temperature, the moving member 11 is in close contact with the heat source 2, the fixed member 12 is connected with the cold source 3, and the thermal switch 1 is in a conductive state at this time. After the cold source 3 starts to work, the temperature of the cold source 3 gradually decreases, the temperature of the fixing piece 12 tightly connected with the cold source 3 decreases, and the heat of the heat source 2 is sequentially transferred to the cold source 2 through the moving piece 11, the first extending piece 111, the second extending piece 121 and the fixing piece 12 and is taken away by the cold source 3, so that the temperature of the heat source 3 continuously decreases. During the temperature decrease of the fixed part 12, the temperature of the gas in the telescopic part 13 also gradually decreases, the volume of the first cavity 14 gradually contracts, and the pressure of the contact between the moving part 11 and the heat source 2 also gradually decreases, but still keeps in contact. When the temperature of the heat source 2 is reduced to the working temperature range, the shrinkage of the telescopic member 13 also reaches a preset value, and the movable member 11 is thoroughly separated from the heat source 2, so that the thermal switch 1 is in an off state.

When the temperature of the heat source 3 increases, the volume of the gas in the expansion piece 13 expands, and the moving piece 11 is contacted with the heat source 2 again, so that the heat source 2 and the heat source 3 are in a conducting state again.

Fig. 2 is a schematic structural diagram of a thermal switch 1 according to a second embodiment of the present invention, which is basically similar to the main structural components and the working process of the thermal switch 1 according to the first embodiment, and also includes a moving member 11, a fixed member 12, and a telescopic member 13, wherein a second cavity 15 formed by a first extending member 111 and a second extending member 121 is disposed at the outside, and two ends of the telescopic member 13 are respectively connected with the moving member 11 and the fixed member 12 through the first extending member 111 and the second extending member 121, so as to form a closed first cavity 14 disposed inside the second cavity 15. The first cavity 14 is also filled with a working medium, and the volume of the working medium expands or contracts along with the temperature change, so that the telescopic member 13 stretches and contracts, and the moving member 11 and the fixed member 12 relatively move, and in the process, the contact surfaces between the first extending member 111 and the second extending member 121 always keep mutual contact, and the relative sliding can smoothly occur. The expansion member 13 may be provided in a tubular structure or may be provided in an integral bladder structure.

In the present embodiment, a communication hole 151 is provided at the bottom of the second extension member 121, and unlike the first embodiment shown in fig. 1, the communication hole 151 is used to communicate the second cavity 15 with the outside of the thermal switch 1, and the second cavity 15 always maintains the same pressure with the outside, so that the relative sliding between the first extension member 111 and the second extension member 121 occurs more smoothly. At least one communication hole 151 and/or a communication groove (not shown) may be formed in the first extension member 111 and/or the second extension member 121 to achieve the same or better communication effect.

Fig. 3 is a schematic structural view of a thermal switch 1 according to a third embodiment of the present invention, which is substantially similar to the main structural composition and operation of the thermal switch 1 according to the first embodiment, and includes a moving member 11, a fixed member 12, and a telescopic member 13, wherein a plurality of first extending members 111 and second extending members 121 are provided in this embodiment, each of the first extending members 111 and each of the second extending members 121 are alternately arranged, and adjacent first extending members 111 and second extending members 121 are in contact with each other, so that relative movement can occur, and heat can be smoothly transferred between the moving member 11 and the fixed member 12. Such a structure can greatly increase the heat transfer contact area between the moving member 11 and the fixed member 12, and reduce the heat transfer resistance between the moving member 11 and the fixed member 12.

In the present embodiment, the cross-sectional structures of the first extension member 111 and the second extension member 121 perpendicular to the moving direction may be annular structures or strip structures.

Fig. 4 is a schematic structural diagram of a thermal switch 1 according to a fourth embodiment of the present invention, in addition to the basic structure of the first embodiment, a second fixing member 17 is additionally provided, the second fixing member 17 is connected with the fixing member 12 through a supporting member 16, the fixing member 12 and the second fixing member 17 are respectively connected with the cold source 3 and the heat source 2, and the thermal conduction on-off of the thermal switch 1 is realized through the contact and separation between the moving member 11 and the second fixing member 17. The supporting member 16 is used for fixing, supporting and insulating, the supporting member 16 can be made of materials with low thermal conductivity, and the supporting member 16 can be in a strip shape, a rod shape, a sheet shape or a thin cylindrical shape, or other structural forms with good heat insulation effect and good strength.

Fig. 5 is a schematic diagram of an insulating support structure, in which the support members 16 are in a rod-shaped structure, and four support members are uniformly distributed between the fixing member 12 and the second fixing member 17, so that not only can the strength support requirement be met, but also a good insulating effect can be achieved, and the thermal switch 1 has a larger breaking thermal resistance, so that a larger switching ratio is obtained.

In the present embodiment, the second fixing member 17 and the supporting member 16 may be combined not only with the basic structure shown in the first embodiment but also with the second embodiment, the third embodiment, or other structural forms. The advantage of this embodiment is that the contact and separation actions of the thermal switch 1 occur inside the thermal switch 1, and the moving member 11 does not frequently contact or separate from the heat source 2 or the cold source 3, so as to avoid frequent acting force on the heat source 2 or the cold source 3.

Fig. 6 is a schematic structural view of a thermal switch 1 according to a fifth embodiment of the present invention, which is different from the fourth embodiment shown in fig. 4 in that a third extension member 171 is further provided on the second fixing member 17, and the surface of the third extension member 171 opposite to the inner side surface of the second fixing member 17 is used to contact or separate from the moving member 11, so that the thermal switch 1 realizes an on-off mode in the opposite direction.

The operation of one of the operation modes of the present embodiment will be described below using the thermal switch 1 operating at the level Wen Wenou as an example, in which the first chamber 14 is filled with a gas under a certain pressure, the expansion member 13 is in an expanded state at room temperature, the moving member 11 is not in direct contact with the third extending member 171, and the fixed member 12 is connected to the cold source 3, and at this time, the thermal switch 1 is in an off state. When the cold source 3 starts to operate, the temperature of the cold source 3 gradually decreases, the temperature of the fixing member 12 tightly connected to the cold source 3 also gradually decreases, the gas temperature in the expansion member 13 also gradually decreases, the volume of the first cavity 14 gradually contracts, and the distance between the moving member 11 and the third extending member 171 gradually decreases.

When the temperature of the heat source 3 is reduced to the working temperature range, the shrinkage of the expansion member 13 also reaches the preset value, the moving member 11 contacts with the third extending member 171, and at this time, the thermal switch 1 is in the on state, and the heat of the heat source 2 is sequentially transferred to the heat source 2 through the second fixing member 17, the third extending member 171, the moving member 11, the first extending member 111, the second extending member 121 and the fixing member 12, and is taken away by the heat source 3, so that the temperature of the heat source 3 is continuously reduced. When the temperature of the heat source 2 is reduced to a desired low temperature condition, the heat source 3 may be turned off or the temperature of the heat source 3 may be raised by active control, and after the temperature of the heat source 3 is raised, the volume of the working medium in the expansion member 13 expands, the expansion member 13 expands accordingly, and the moving member 11 is disconnected from the third extending member 171 again, thereby putting the heat source 2 and the heat source 3 in a disconnected state again.

In the above embodiments, in order to reduce the contact thermal resistance between the moving member 11 or the fixed member 12 and other parts, an indium film or an indium sheet may be provided at the position of the contact surface. In order to reduce the amount of radiation heat exchange between the moving member 11 and the other contact member, a plating treatment may be performed on the contact surface.

In summary, the moving member 11 is driven to move by expansion and contraction of the working medium, so that the displacement of the moving member 11 is large, the thermal switch 1 can obtain a large switching ratio, and the thermal switch has a simple structure and low processing technology requirements. When the extension piece is used for connecting the moving piece 11 and the fixed piece 12, the length of the thermal switch 1 can be prolonged according to the actual application requirement, the heat transfer arrangement can be conveniently carried out when the cold source 3 and the heat source 2 are far away from each other in the cooling system, the contact area between the moving piece 11 and the fixed piece 12 can be increased, the heat transfer resistance between the moving piece 11 and the fixed piece 12 is reduced, the extension piece 13 can also play a role in positioning, the moving piece 11 is prevented from being deviated or inclined in the moving process, the moving piece 11 can be better contacted with the contact piece, and the thermal switch 1 can achieve a larger switching ratio.

The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, alternatives, and improvements that fall within the spirit and scope of the invention.

Claims

1. A thermal switch, comprising:

The heat source device comprises a moving part, a fixing part and a telescopic part, wherein the moving part is arranged towards the heat source, a cold source is arranged on the fixing part, the telescopic part is arranged between the moving part and the fixing part, two ends of the telescopic part are respectively connected with the moving part and the fixing part, the telescopic part, the moving part and the fixing part form a closed first cavity together, working medium changing along with temperature is filled in the first cavity, the working medium expands or contracts in the first cavity to promote the telescopic part to stretch out and retract, and the moving part and the fixing part are driven to move relatively through the stretching and retracting of the telescopic part, so that the moving part and the heat source are connected and disconnected;

The moving part is connected with the fixed part through the extending part, at least one surface of the moving part is contacted with the fixed part, and the moving part and the fixed part can slide along the contacted surface, so that the moving part and the fixed part relatively move,

The thermal switch further comprises a second fixing piece and a supporting piece, wherein the second fixing piece is arranged above the moving piece, and the supporting piece is arranged between the fixing piece and the second fixing piece and is located on the outer side of the telescopic piece.

2. The thermal switch of claim 1, further comprising an extension member comprising a first extension member and a second extension member, wherein the first extension member is coupled to the moving member and the second extension member is coupled to the fixed member.

3. The thermal switch of claim 2 wherein said first extension and said second extension are a male fit.

4. A thermal switch according to claim 3, wherein a projection extending in a direction toward the fixed member is formed on a lower surface of the movable member, and an annular cavity opening toward the movable member is formed on an upper surface of the fixed member, wherein the projection is inserted into the annular cavity and is capable of extending and retracting movement with respect to a longitudinal direction of the annular cavity.

5. A thermal switch according to claim 3, wherein a plurality of first protrusions extending in the direction of the fixed member are formed on the lower surface of the movable member, a plurality of second protrusions extending in the direction of the movable member are formed on the upper surface of the fixed member, and one of the second protrusions is provided between each two adjacent first protrusions.

6. The thermal switch of claim 4, wherein a closed second cavity is configured between the first extension and the second extension, a communication hole is configured on a side wall of the annular cavity, and the first cavity is communicated with the second cavity through the communication hole; or (b)

The communication hole communicates the second chamber with the outside.

7. The thermal switch of claim 6 wherein said telescoping member is located outside of said annular cavity and said second cavity is located within said first cavity; or the telescopic piece is positioned on the inner side of the annular cavity, and the first cavity is positioned in the second cavity.

8. The thermal switch according to claim 1, wherein a heat source is mounted on the second stationary member, and switching on and off of the moving member and the heat source is achieved by contact and separation between the moving member and the second stationary member.

9. The thermal switch of claim 8, further comprising a third extension member including an annular portion provided at a lower surface of the second fixing member and extending toward the fixing member and a horizontal stopper portion provided at a lower opening edge of the annular portion and extending toward a center line direction of the annular portion, the horizontal stopper portion and the second fixing member together forming a first space, the moving member being provided in the first space, the moving member being capable of reciprocating up and down in the first space with the first extension member, both ends of the moving member being capable of being overlapped on an upper surface of the horizontal stopper portion.