WO2006054488A1

WO2006054488A1 - Piezoelectric pump and stirling refrigerator

Info

Publication number: WO2006054488A1
Application number: PCT/JP2005/020694
Authority: WO
Inventors: Hengliang Zhang
Original assignee: Sharp Kabushiki Kaisha
Priority date: 2004-11-17
Filing date: 2005-11-11
Publication date: 2006-05-26
Also published as: JP3949135B2; JP2006144591A; KR20070073973A; CN101057077A; US20080101965A1; EP1813811A1

Abstract

A piezoelectric pump and a Stirling refrigerator. The piezoelectric pump (6) comprises a casing (32) formed by welding a plurality of metal members to each other, a piezoelectric element (36) partitioning a space in the casing (32) into an operating space (34) and a back pressure space (35), and resin internal parts (33A, 33B) installed between the casing (32) and the piezoelectric element (36) and holding the piezoelectric element (36). The internal parts (33A, 33B) are formed of an easy-to-machine and easy-to-mold resin. The internal part (33A) specifies the outer periphery of the operating space (34) and the internal part (33B) specifies the outer periphery of the back pressure space (35). Since a recessed part is formed between the internal parts (33A, 33B) by facing the internal parts (33A, 33B) each other, the piezoelectric element (36) can be holdingly stored in the recessed part.

Description

Specification

Piezoelectric pump and Stirling refrigerator

Technical field

TECHNICAL FIELD [0001] The present invention relates to a piezoelectric pump and a Stirling Refrigerator / Freezer, and more particularly to a piezoelectric pump that efficiently circulates fluid in a negative pressure / positive pressure state and a Stirling refrigerator equipped with the piezoelectric pump. About.

Background art

As a pump for circulating a medium, a piezoelectric pump using a piezoelectric element such as crystal or lithium niobate has been conventionally used.

FIG. 6 is a cross-sectional view showing an example of a conventional piezoelectric pump. Referring to FIG. 6, the piezoelectric pump 106 includes a casing 132 and a working space 134 and a back pressure space 135 in the casing 132 as shown in FIG. Here, the working space 134 and the back pressure space 135 are separated by the piezoelectric element 136. The casing on the working space 134 side is provided with an inlet portion 137 for sucking the medium and an outlet portion 138 for discharging the medium. The casing on the back pressure space 135 side is provided with the pressure of the back pressure space 135. A back pressure hole 135A for adjustment is provided. Note that the inlet portion 137 and the outlet portion 138 are provided with check valves 139 and 140 that do not allow the medium to flow backward, respectively.

When the above-described piezoelectric pump 106 is operated, an electric signal is given to the piezoelectric element 136. As a result, the piezoelectric element 136 performs an amplitude motion in the direction of the dashed arrow in FIG. At this time, the end of the piezoelectric element 136 is fixed to the casing 132, and the piezoelectric element 136 performs an amplitude motion while being deformed into a convex shape. As a result, the volume of the working space 134 varies, the pressure in the working space 134 varies according to the deformation state of the piezoelectric element 136, and the medium is sucked and discharged.

Here, due to the deformation of the piezoelectric element 136, the volume of the back pressure space 135 also changes. As a result, when the pressure in the back pressure space 135 fluctuates, the movement direction of the piezoelectric element 136 is reversed. As a result, the operation efficiency of the piezoelectric pump 106 is reduced. In contrast, the pressure in the back pressure space 135 is constant regardless of the deformation state of the piezoelectric element 136. Thus, a back pressure hole 135A is provided on the back pressure space 135 side of the casing 132.

[0006] Further, assuming that heat exchange by a reverse Stirling cycle is applied to a refrigerator, for example,

And those described in JP-A-2003-50073 (conventional example 1).

[0007] In Conventional Example 1, a high temperature portion for releasing the compression heat of the working gas due to the reverse Stirling cycle to the outside, a low temperature portion for absorbing the expansion heat of the working gas due to the reverse Stirling cycle from the outside, Cooling heat that transports the cold heat of the low temperature section with a low temperature side circulation circuit that has a closed circuit force that connects a low temperature side condenser thermally coupled to the low temperature section and a plurality of low temperature side evaporators to form a thermosiphon A Stirling refrigeration system is disclosed in which a carrier medium is enclosed in a low-temperature side circulation circuit. Here, the heat in the high temperature part is dissipated from the high temperature side heat exchange cycle (heat dissipation system). The high temperature side heat exchange cycle includes a high temperature side evaporator and a high temperature side condenser connected by piping, and heat is transferred and released by the thermosyphon principle.

[0008] In registered utility model No. 2505727 (conventional example 2), a casing, a piezoelectric vibrator provided inside the casing, and a pump chamber on one side of the piezoelectric vibrator are provided. A piezoelectric pump having a suction check valve and a discharge check valve is disclosed. In this piezoelectric pump, the pump chamber communicates with an anti-pump chamber located on the opposite side of the pump chamber with respect to the piezoelectric vibrator.

Patent Document 1: Japanese Patent Laid-Open No. 2003-50073

Patent Document 2: Registered Utility Model No. 2505727

Disclosure of the invention

Problems to be solved by the invention

However, the piezoelectric pump as described above has the following problems.

In the piezoelectric pump as shown in FIG. 6, a casing is formed by using a plurality of opposing members so as to form a space inside. Here, sealing between a plurality of members is generally performed using an O-ring or the like. In such a configuration, since a slow leak of the working medium occurs, in a closed system in which the pressure in the circuit is lower or higher than the atmospheric pressure (referred to herein as a negative pressure state or a positive pressure state). It cannot be used for a long time. Such a problem is caused by the piezoelectric pump shown in Conventional Example 2. Will not be resolved.

[0010] In addition, since the piezoelectric element used in the piezoelectric pump has low heat resistance, in order to improve the sealing performance, when joining the plurality of members by welding, how to transfer the welding heat to the piezoelectric element. The question is whether to do it. By reducing the amount of heat transmitted to the piezoelectric element, the function of the piezoelectric element is improved, and as a result, the fluid circulation efficiency is improved.

The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a piezoelectric pump and a Stirling cooler that efficiently circulates fluid in a negative pressure-positive pressure state. It is in.

Means for solving the problem

[0012] A piezoelectric pump according to the present invention includes a casing formed by joining a plurality of metal members, a piezoelectric element that partitions a space in the casing into first and second internal spaces, a casing, and a piezoelectric element. And a non-metallic first and second internal parts for holding the piezoelectric element.

[0013] It is preferable that the plurality of metal members constituting the casing are joined by welding.

By joining the members by welding, durability against leakage of the working medium can be improved. As a result, a piezoelectric pump that can be used for a long time in a closed system that operates at a pressure lower or higher than atmospheric pressure is provided. Further, by providing a non-metallic internal part between the metal casing and the piezoelectric element and separating the casing and the piezoelectric element, it is possible to suppress welding heat from being transmitted to the piezoelectric element.

[0014] Here, the first and second internal parts are made of resin, and the first and second internal parts respectively define outer peripheries of the first and second internal spaces, and the first and second internal parts It is preferable to hold the piezoelectric element so that the piezoelectric element is sandwiched between them.

[0015] A piezoelectric pump can be manufactured at low cost by using a resin that can be easily molded and holding the piezoelectric element with a simple structure.

[0016] In one aspect, the piezoelectric pump is formed on a first internal component, and an inlet portion through which a working medium directed to the first internal space serving as a suction pipe force working space outside the casing passes, (1) An outlet formed on an internal part and through which a working medium that passes from the first inner space to a discharge pipe outside the casing passes, and a first installed between the inlet and the first inner space. A check valve, a second check valve installed between the outlet portion and the first inner space, a gap between the first and second inner spaces and the piezoelectric element, an inlet portion and an outlet portion And a plurality of O-rings each sealing a gap between the casing and the casing. Here, in the first internal part, the first and second check valve installation portions where the first and second check valves are respectively installed, and the plurality of groove portions where the plurality of O-rings are respectively installed. Is preferably provided.

[0017] In this configuration, by providing a recess or groove in an internal part made of grease, an installation table or groove in which a check valve and an O-ring are provided can be easily formed.

[0018] Here, the communication device further includes a communication portion that communicates the second internal space as the back pressure space with the inlet portion or the outlet portion, and the communication portion is formed by holes or grooves formed in the first and second internal components. Preferably, it is configured.

[0019] By forming the communication portion, the pressure in the working space (first internal space) and the back pressure space (second internal space) can be made substantially equal. Further, by providing a groove hole in the internal part made of resin, the communication part can be easily formed without providing a communication pipe outside the casing. As a result, a compact piezoelectric pump that circulates fluid efficiently can be formed at low cost.

[0020] Further, it is preferable that the communication portion communicates with a joint portion of a plurality of metal members in the casing. Thereby, the communication part can be used as a leak check hole of the casing.

[0021] In another aspect, the piezoelectric pump is formed on a first internal part, and a first suction pipe force outside the casing passes through a working medium facing the first internal space as a working space. Part, a second inlet pipe formed on the second internal part and through which the working medium directed to the second internal space as the working space outside the casing passes, and on the first internal part The first internal space force is formed on the second outlet part and the first outlet part through which the working medium that flows toward the first discharge pipe outside the casing passes, and from the second internal space to the first outlet part outside the casing. (2) a second outlet portion through which the working medium facing the discharge pipe passes, and first and second check valves respectively installed between the first and second inlet portions and the first and second internal spaces A third and a third outlet installed between the first and second outlets and the first and second internal spaces, respectively; 4 and the check valve, the gap between the first and second inner space and the piezoelectric element, the first and second input And a plurality of O-rings for sealing the opening and the gap between the first and second outlets and the casing, respectively. Here, the first to fourth check valve forces S are installed in the first and second internal parts, respectively, and the first to fourth check valve installation portions and the plurality of groove portions in which the plurality of O-rings are respectively installed. It is preferable to set up with.

In this configuration, both sides of the piezoelectric element can be used as the working space. In addition, by providing a recess or groove in an internal part made of a resin, it is possible to easily form an installation base or groove on which a check valve or an O-ring is provided. As a result, a piezoelectric pump that circulates fluid efficiently is provided at low cost.

[0023] It is preferable to provide a communication hole for communicating the first or second inlet portion or the first or second outlet portion with the joint portion of the metal member.

[0024] This communication hole can be used as a leak check hole of the casing.

In still another aspect, the piezoelectric pump is formed on a first internal component, and a suction pipe force outside the casing, a first inlet portion through which a working medium that passes through the first internal space as the working space passes, (2) Force at the first inlet formed on the internal part The second inlet through which the working medium directed to the second internal space passes, and formed on the first internal part, from the first internal space to the exterior of the casing A first outlet portion through which the working medium toward the discharge pipe passes, a second outlet portion formed on the second internal part and through which the working medium directed toward the first outlet portion passes, 1 and 2 are formed by holes or grooves formed in the second internal part, and the first communication part is formed by holes and grooves formed in the first and second internal parts. A second communication part for communicating the first outlet with the second outlet part, the first and second inlet parts, and the first and second parts. First and second check valves installed between the first and second outlet spaces, and third and fourth check valves respectively installed between the first and second outlet portions and the first and second inner spaces. A plurality of Os for sealing the valve, the gap between the first and second inner spaces and the piezoelectric element, and the gap between the first and second inlet portions and the first and second outlet portions and the casing, respectively. Provide a ring and more. Here, the first to fourth check valves are installed in the first and second internal parts, respectively, the first to fourth check valves are installed, and the plurality of grooves are installed with a plurality of O-rings. Is preferably provided.

In this configuration, both sides of the piezoelectric element can be used as the working space. Also The first and second communication portions can be formed without providing a communication pipe outside the casing. In addition, by providing recesses and grooves in the internal parts made of grease, it is possible to easily form installation bases and grooves on which check valves and O-rings are provided. As a result, a compact piezoelectric pump that efficiently circulates fluid is provided at low cost.

[0026] Here, one of the first and second communicating portions may be communicated with a joint portion of the metal member in the casing. Thereby, the communication part can be used as a leak check hole of the casing.

[0027] Further, another O-ring for sealing the first communication part or the second communication part may be further provided at the joint surface between the first internal part and the second internal part. As a result, it is possible to ensure the hermeticity of the first and second communicating portions that serve as a passage for the working medium.

[0028] It should be noted that each of the plurality of metal members constituting the casing may have a flange portion, and the casing may be formed by welding the front end portions of the flange portion. Thereby, a welding location and a piezoelectric element can be further moved away. Therefore, the effect of suppressing heat input to the piezoelectric element can be further enhanced.

In the Stirling refrigerator according to the present invention, the above-described piezoelectric pump is provided in the working medium circulation circuit on the high temperature side.

The invention's effect

[0030] According to the present invention, there is provided a piezoelectric pump in which a slow leak does not occur even if it is used for a long time in a negative pressure / positive pressure sealed system.

Brief Description of Drawings

[0031] FIG. 1 is an example of a piping system diagram of a Stirling refrigerator.

FIG. 2 is a cross-sectional view of the piezoelectric pump according to the first embodiment of the present invention.

FIG. 3 is a cross-sectional view of a piezoelectric pump according to Embodiment 2 of the present invention.

FIG. 4 is a cross-sectional view of a piezoelectric pump according to Embodiment 3 of the present invention.

FIG. 5 is an example of a side sectional view showing a Stirling refrigerator in a Stirling refrigerator.

FIG. 6 is a cross-sectional view of a conventional piezoelectric pump.

Explanation of symbols [0032] 1 Stirling refrigerator, 2 heat dissipating section, 2A to 2F pipe (high temperature side circulation circuit), 3 heat absorption section, 3A, 3B Neuve (low temperature side circulation circuit), 4 Stirling refrigerator, 5 high temperature side evaporator, 6 Circulation pump, 7 Hot condenser, 8 Fan, 9 Anti-condensation pipe, 10 Low condenser, 11 Low evaporator, 12 Fan, 13 Cylinder, 14 Piston, 15 Displacer, 16 Regenerator, 17 Operation Space, 17A Compression space, 17B Expansion space, 18, 19 Heat exchanger, 18A tube, 20 Inner yoke, 21 Moving magnet, 22 Outer yoke, 23 Linear motor, 24 Piston spring, 25 Displacer spring, 26 Displacer rod, 27 Back pressure space, 28 plate panel, 29 balance mass, 30, 32 casing, 33A, 33B internal parts, 34, 34A, 34B working space, 35 back pressure space, 36 piezoelectric element, 37, 37A, 37B inlet, 38, 38A, 38B Outlet, 39, 39A, 39B, 40, 40A, 40B Check valve, 41, 41A, 41B Inlet ronop, 42, 42A, 42B Outlet ronop, 4 3 O-ring, 44 communicating portion, 44A Leak check hole, 44B Inlet communication section, 44C outlet communication section, 45 power terminal, 46 flange section.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of a piezoelectric pump and a Stirling cooler according to the present invention will be described with reference to FIGS. 1 to 5.

In the specification of the present application, “cooling box” is a concept including all of “refrigerator”, “freezer”, and “freezer refrigerator”.

[0035] Further, in this specification, a Stirling cooler as a Stirling engine-equipped device equipped with a Stirling refrigerator will be described. However, a Stirling engine-equipped device in which the piezoelectric pump according to the present invention is installed is a Stirling cooler. Not limited to

. The Stirling engine is also used as a generator, for example.

[0036] (Explanation about Stirling refrigerator)

FIG. 1 is an example of a piping system diagram of a Stirling cooler in which a piezoelectric pump according to Embodiments 1 to 3 of the present invention to be described later is provided in a working medium circulation circuit on a high temperature side.

[0037] As shown in FIG. 1, the Stirling refrigerator 1 includes a Stirling refrigerator 4 (Stirling engine) having a heat dissipating part 2 and a heat absorbing part 3, a high-temperature side evaporator 5 attached to the heat dissipating part 2, 1st high-temperature side circulation circuit (first circulation circuit) including high-temperature side condenser 7 and pipes 2A and 2B, and high temperature Side evaporator 5, circulation pump 6, dew prevention pipe 9 and pipes 2C, 2D, 2E, 2F, 2nd high temperature side circulation circuit (second circulation circuit), and low temperature side condenser 10 attached to heat absorption part 3 And a low temperature side circulation circuit including the low temperature side evaporator 11 and the pipes 3A and 3B. The first high temperature side circulation circuit cools the heat dissipating part 2 of the Stirling refrigerator 4, and the second high temperature side circulation circuit supplies heat to the dew condensation prevention pipe 9. Further, the low-temperature side circulation circuit performs heat exchange between the air in the refrigerator and the heat absorption part 3 of the Stirling refrigerator 4.

[0038] Water (H20) or the like is sealed as a refrigerant in the first and second high-temperature side circulation circuits. The refrigerant evaporated in the high temperature side evaporator 5 reaches the high temperature side condenser 7 via the pipe 2A (high temperature side conduit) (broken arrow in FIG. 1). The refrigerant is condensed by heat exchange with the outside air in the high-temperature side condenser 7. In order to promote this heat exchange, a fan 8 for generating an air flow is provided in the vicinity of the high-temperature side condenser 7. The condensed refrigerant returns to the high temperature side evaporator 5 via the pipe 2B (high temperature side return pipe). In the first high-temperature side circulation circuit, the high-temperature side condenser 7 is used so that the heat generated in the heat dissipating section 2 can be transferred using the natural circulation caused by the evaporation and condensation of the refrigerant. It is arranged above the high temperature side evaporator 5. In order to adjust the boiling point of the refrigerant, the pressure in the circulation circuit system is adjusted (substantially reduced in vacuum).

On the other hand, a pipe 2 C is connected to the lower part of the high temperature side evaporator 5. High-temperature side evaporator 5 Power pipe Liquid refrigerant flows into pipe 2C. The refrigerant flowing into the pipe 2C reaches the circulating pump 6 provided below the Stirling refrigerator 4 through the pipe 2D. The refrigerant discharged from the circulation pump 6 is sent to the dew condensation prevention pipe 9 through the pipe 2E. Here, the refrigerant flowing in the dew generation preventing noise 9 is kept at a relatively high temperature by the heat given from the heat dissipating part 2 of the Stirling refrigerator 4. Therefore, by providing the dew prevention pipe 9 on the front surface of the refrigerator, it is possible to suppress dew generation at the door portion and the like. The refrigerant that has flowed through the dew prevention pipe 9 returns to the high temperature side evaporator 5 through the pipe 2F. Thus, forced circulation by the circulation pump 6 is performed in the second high temperature side circulation circuit.

[0040] Carbon dioxide, hydrocarbons, or the like is sealed as a refrigerant in the low temperature side circulation circuit.

The refrigerant condensed in the low temperature side condenser 10 reaches the low temperature side evaporator 11 via the pipe 3A (low temperature side conduit). Low temperature side evaporator 11! As the refrigerant evaporates, heat exchange takes place Is called. In order to promote this heat exchange, a fan 12 for generating an air flow is provided in the vicinity of the low-temperature side evaporator 11. After the heat exchange, the gasified refrigerant returns to the low temperature side condenser 10 via the pipe 3B (low temperature side return pipe). In the low-temperature side circulation circuit, the low-temperature side evaporator 11 is thus connected to the low-temperature side condensation so that the cold heat generated in the heat-absorbing section 3 can be transmitted using the natural circulation caused by the evaporation and condensation of the refrigerant. It is arranged below the vessel 10. Also, in order to adjust the boiling point of the refrigerant, the pressure in the circulation circuit system is adjusted (substantially reduced to a vacuum state).

When the Stirling refrigerator 4 is operated, heat generated in the heat radiating unit 2 of the refrigerator 4 is exchanged with air through the high-temperature side condenser 7. On the other hand, the cold generated in the heat absorption part 3 of the Stirling refrigerator 4 is heat-exchanged with the air in the refrigerator through the low temperature side evaporator 11. The warm air flowing from the inside of the refrigerator is sent again to the vicinity of the low temperature side evaporator 11 and repeatedly cooled.

[0042] (Embodiment 1)

FIG. 2 is a cross-sectional view showing the piezoelectric pump according to the first embodiment.

As shown in FIG. 2, the piezoelectric pump 6 according to the present embodiment includes a casing 32 formed by welding a plurality of metal members, and a space in the casing 32 as a working space 34 (first internal Space) and back pressure space 35 (second internal space), and a non-metallic internal component 33A, which is provided between the casing 32 and the piezoelectric element 36 and holds the piezoelectric element 36. 33B (first and second internal parts).

[0044] The internal parts 33A and 33B are made of a resin that is easily processed and molded. The internal part 33A defines the outer periphery of the working space 34 (pump chamber), and the internal part 33B defines the outer periphery of the back pressure space 35. By making the internal parts 33A and 33B face each other, a recess is formed between the internal parts 33A and 33B, and the piezoelectric element 36 is received and held in the recess. That is, the internal parts 33A and 33B hold the piezoelectric element 36 so as to sandwich the piezoelectric element 36.

In the example of FIG. 2, an inlet 37 formed on the internal part 33A and through which the working medium passes from the inlet pipe 41 (suction pipe) outside the casing 32 to the working space 34, and the internal part 33A Formed in the working space 34 to the casing 32 outlet pipe 42 (discharge pipe) ) Between the outlet portion 38 through which the working medium passes, the check valve 39 (first check valve) installed between the inlet portion 37 and the working space 34, and the outlet portion 38 and the working space 34. Check valve 40 (second check valve) installed between the working space 34 and the back pressure space 35 and the piezoelectric element 36, the inlet 37 and outlet 38 and the inner surface of the casing 32 Are provided with a plurality of O-rings 43 that seal the gaps between the two and each other. Here, the installation base on which the check valves 39 and 40 are respectively installed (the first and second check valve installation portions) and the groove portion on which each O-ring 43 is installed are provided in advance in the internal parts 33A and 33B. It is provided by processing.

The piezoelectric pump 6 has a communication portion 44 that allows the back pressure space 35 and the inlet portion 37 to communicate with each other. The communication part 44 is configured by a hole or groove formed in the internal parts 33A and 33B. The communication portion 44 reaches the inner surface of the casing 32 and communicates with the welded portions of the plurality of metal members. Instead of the communication part 44, a communication part for communicating the back pressure space 35 and the outlet part 38 may be provided.

When actually operating the piezoelectric pump 6, an electric signal is given to the piezoelectric element 36 via the power supply terminal 45, and the piezoelectric element 36 is moved in an amplitude direction in the left-right direction in FIG.

[0048] In the above configuration, the durability against leakage of the working medium can be improved by joining a plurality of members constituting the casing 32 by welding. As a result, there is provided the piezoelectric pump 6 that can be used for a long time in a closed system of negative pressure and positive pressure. In addition, the inner parts 33A and 33B made of resin are provided between the metal casing 32 and the piezoelectric element 36, and the casing 32 and the piezoelectric element 36 are separated from each other, so that the welding heat at the time of welding the metal member is increased. Can be prevented from being transmitted to the piezoelectric element 36. Therefore, the operation efficiency of the piezoelectric element 36 is improved, and as a result, the circulation efficiency of the working medium is improved.

[0049] Also, as the internal parts 33A and 33B, a resin-made part that can be easily molded is used, and the piezoelectric pump 36 is held at a low cost by holding the piezoelectric element 36 with a simple structure as described above. Can be produced.

[0050] In addition, the installation base and groove in which the check valves 39 and 40 and the plurality of O-rings 43 are provided can be easily formed by providing recesses and grooves in the resin internal parts 33A and 33B. it can.

[0051] Furthermore, by forming the communication portion 44, the working space 34 (first internal space) and the back pressure air The pressure in the space 35 (second internal space) can be kept approximately equal. As a result, the circulation efficiency of the working medium is improved in the negative pressure / positive pressure state. Here, the communication part 44 can be easily formed without providing a communication pipe outside the casing by providing grooves in the internal parts 33A, 33B made of resin. As a result, the compact structure of the piezoelectric pump 6 can be realized at low cost. Further, the communication portion 44 can be used as a leak check hole (communication hole) of the casing by communicating the communication portion 44 with a welded portion of a plurality of metal members.

Each of the plurality of metal members constituting the casing 32 has a flange portion 46, and the casing 32 is formed by welding the front end portions of the flange portion 46. By providing the flange portion 46, the welded portion and the piezoelectric element 36 can be further away from each other. Therefore, the effect of suppressing heat input to the piezoelectric element 36 can be further enhanced.

[0053] (Embodiment 2)

FIG. 3 is a sectional view showing the piezoelectric pump according to the second embodiment.

[0054] The piezoelectric pump 6 according to the present embodiment is a modification of the piezoelectric pump 6 according to the first embodiment, and uses both sides of the piezoelectric element 36 as pump chambers (operating spaces 34A, 34B). Features.

As shown in FIG. 3, the piezoelectric pump 6 is formed on the internal part 33A (first internal part), and from the inlet pipe 41 A (first suction pipe) outside the casing 32 to the working space 34A (first 1 Internal space) Directing force 37A (first inlet part) through which the working medium passes and the internal part 33B (second internal part) are formed on the inlet pipe 41B (second suction pipe) outside the casing 32 An inlet 37B (second inlet) through which the working medium directed to the working space 34B (second inner space) passes and an inner part 33A are formed on the inner part 33A, and the outlet pipe outside the casing 32 from the working space 34A. 42A (first discharge pipe) Directing force 38A (first outlet) through which the working medium passes and the inner part 33B are formed on the inner part 33B, and the working space 34B force is also outside the casing 32. The outlet part 38B (second outlet part) through which the working medium heading to the pipe) passes and the inlet parts 37A, 37B Check valves 39A and 39B (first and second check valves) installed between the spaces 34A and 34B, respectively, and between the outlet portions 38A and 38B and the working spaces 34A and 34B, respectively. Check valves 40A and 40B (third and fourth check valves), working spaces 34A and 34B and piezoelectric element 3 And a plurality of O-rings 43 that seal the gaps between the inlets 37A and 37B and the outlets 38A and 38B and the inner surface of the casing 32, respectively. Here, the installation base on which the check valves 39A, 39B, 40A, 40B are respectively installed (the first to fourth check valve installation portions) and the groove portion on which each O-ring 43 is installed are The parts 33A and 33B are provided by machining in advance.

[0056] Piezoelectric pump 6 has leak check holes 44A (communication holes) in internal parts 33A and 33B that reach the inner surface of casing 32 from inlets 37A and 37B and communicate with the welded portions of a plurality of metal members. . The leak check hole 44A may be provided only in one of the internal parts 33A and 33B. Instead of the leak check hole 44A, the leak check hole 44A reaches the inner surface of the casing 32 from the outlet portions 38A and 38B, and a plurality of metals. A leak check hole communicating with the welded part of the manufactured member may be provided.

Also with the above configuration, as in the first embodiment, the piezoelectric pump 6 with high circulation efficiency that can be used for a long period in a closed system of negative pressure and positive pressure is provided at low cost.

[0058] Furthermore, the leakage check of the casing can be performed by communicating the leak check hole 44A with the welded portions of the plurality of metal members.

[0059] In the present embodiment, detailed description of the same matters as in the above-described first embodiment will not be repeated.

[0060] (Embodiment 3)

FIG. 4 is a cross-sectional view showing the piezoelectric pump according to the third embodiment.

[0061] The piezoelectric pump 6 according to the present embodiment is a modification of the piezoelectric pump 6 according to the first embodiment, and uses both sides of the piezoelectric element 36 as pump chambers (operating spaces 34A, 34B). Features.

[0062] As shown in Fig. 4, the piezoelectric pump 6 is formed on the internal part 33A (first internal part), and the inlet 32 of the casing 32 outside the intake 41 (suction pipe) also has a working space 34A (first internal space). Formed on the inlet part 37A (first inlet part) and the internal part 33B (second internal part) through which the working medium that is directed to the directional force passes from the inlet part 37A to the working space 34B (second internal space). Formed on the inlet part 37B (second inlet part) through which the working medium passes and the internal part 33A, the working medium is directed toward the outlet pipe 42 (discharge pipe) outside the working space 3 4A force casing 32 Outlet part 38A (first outlet part), an outlet part 38B (second outlet part) formed on the internal part 33B through which the working medium passes from the working space 34B to the outlet part 38A, and the internal parts 33A, 3 Consists of holes or grooves formed in 3B, and includes inlet communication part 44B (first communication part) that communicates inlet parts 37A and 37B, and holes or grooves formed in internal parts 33A and 33B. An outlet communication part 44C (second communication part) for communicating the outlet parts 38A and 38B, and check valves 39A and 39B (first and first valves) installed between the inlet parts 37A and 37B and the working spaces 34A and 34B, respectively. 2 check valves), check valves 40A and 40B (third and fourth check valves) installed between outlets 38A and 38B and working spaces 34A and 34B, and working spaces 34A and 34B. There are a plurality of O-rings 43 that seal the gap between the piezoelectric element 36 and the gap between the inlet portions 37A and 37B and the outlet portions 38A and 38B and the inner surface of the casing 32. It has been kicked. Here, the installation base on which the check valves 39A, 39B, 40A, 40B are installed (the first to fourth check valve installation parts) and the groove part on which each O-ring 43 is installed are: It is provided by machining the internal parts 33A and 33B in advance.

[0063] Here, the inlet communication portion 44B reaches the inner surface of the casing 32 and communicates the welded portions of a plurality of metal members. Thus, the inlet communication portion 44B can be used as a leak check hole. On the other hand, as shown in FIG. 4, the outlet communication portion 44C is sealed by providing an O-ring (other O-ring) on the joint surface of the internal parts 33A and 33B. Does not communicate. In addition, the inlet communication portion 44B may be sealed, and the outlet communication portion 44C may be communicated with the welding location. In this way, only one of the inlet communication portion 44B and the outlet communication portion 44C is communicated with the welded portion, and the other is sealed with an O-ring, so that the inlet portions 37A, 37B and the outlet portions 38A, which serve as a working medium passage, are provided. It is possible to avoid communicating with 38B.

[0064] Also with the above configuration, as in the first embodiment, the piezoelectric pump 6 with high circulation efficiency that can be used for a long period in a closed system in a negative pressure / positive pressure state is provided at low cost.

[0065] Further, the inlet communication portion 44B and the outlet communication portion 44C can be easily formed without providing a communication pipe outside the casing by providing grooves in the internal parts 33A and 33B made of resin. . As a result, a compact structure of the piezoelectric pump 6 is realized.

[0066] In the present embodiment, the same matters as in the first embodiment described above are described. The detailed explanation will not be repeated.

[0067] (Explanation about Stirling refrigerator)

An example of the structure of Stirling refrigerator 4 and its operation will be described with reference to FIG.

As shown in FIG. 5, the Stirling refrigerator 4 of the present embodiment is a free piston type Stirling engine, which includes a casing 30, a cylinder 13 assembled to the casing 30, and a cylinder. 13 reciprocating piston 14 and displacer 15, regenerator 16, working space 17 including compression space 17A and expansion space 17B, heat dissipating part 2, heat absorbing part 3, and linear as a piston drive means A motor 23, a piston spring 24, a displacer spring 25, a displacer rod 26, and a back pressure space 27 are provided.

[0069] In the example of FIG. 5, the outer shell (outer wall) of the Stirling refrigerator 4 is not composed of a single container, and the casing 30 (bessel portion) located on the back pressure space 27 side and the working space 17 Consists mainly of heat dissipating part 2, tube 18A and heat absorbing part 3 located on the side. The casing 30 defines a back pressure space 27. Various parts including a cylinder 13, a linear motor 23, a piston spring 24, and a displacer spring 25 are assembled in the casing 30. The outer shell is filled with a working medium such as helium gas, hydrogen gas, or nitrogen gas.

[0070] The cylinder 13 has a substantially cylindrical shape, and receives therein a piston 14 and a displacer 15 as a free piston so as to be capable of reciprocating. In the cylinder 13, the piston 14 and the displacer 15 are coaxially spaced apart, and the piston 14 and the displacer 15 partition the working space 17 in the cylinder 13 into a compression space 17A and an expansion space 17B. . More specifically, the working space 17 is a space located closer to the displacer 15 than the end face of the piston 14 on the displacer 15 side, and a compression space 17A is formed between the piston 14 and the displacer 15, and An expansion space 17B is formed between the part 3 and the part 3. The compression space 17A is mainly surrounded by the heat dissipating part 2, and the expansion space 17B is mainly surrounded by the heat absorbing part 3.

[0071] Between the compression space 17A and the expansion space 17B, a regenerator 16 in which a film is wound while having a predetermined gap on the inner peripheral surface of the tube 18A is disposed. Regenerator 1 The compression space 17 </ b> A and the expansion space 17 </ b> B communicate with each other through 6. As a result, a closed circuit is formed in the Stirling refrigerator 4. The working medium enclosed in the closed circuit flows in accordance with the operations of the piston 14 and the displacer 15, thereby realizing a reverse Stirling cycle described later.

A linear motor 23 is disposed in the back pressure space 27 located outside the cylinder 13. The linear motor 23 has an inner yoke 20, a movable magnet portion 21, and an outer yoke 22, and the piston 14 is driven in the axial direction of the cylinder 13 by the linear motor 23.

[0073] One end of the piston 14 is connected to a piston spring 24 composed of a plate panel or the like.

The piston spring 24 functions as an elastic force applying means for applying an elastic force to the piston 14. By applying an elastic force to the piston spring 24, the piston 14 can be reciprocated in the cylinder 13 more stably and periodically. One end of the displacer 15 is connected to a displacer spring 25 via a displacer rod 26. The displacer rod 26 is disposed through the piston 14, and the displacer spring 25 is constituted by a plate panel or the like. The peripheral edge of the displacer spring 25 and the peripheral edge of the piston spring 24 are supported by a support member that extends from the linear motor 23 to the back pressure space 27 side of the piston 14 (hereinafter sometimes referred to as rear).

A back pressure space 27 surrounded by a casing 30 is disposed on the side opposite to the displacer 15 with respect to the piston 14. The back pressure space 27 includes an outer peripheral region located around the piston 14 in the casing 30 and a rear region located closer to the piston spring 24 (rear side) than the piston 14 in the casing 30. A working medium is also present in the back pressure space 27.

A heat exchanger 18 and a heat exchanger 19 are provided on the inner peripheral surfaces of the heat radiating unit 2 and the heat absorbing unit 3, respectively. The heat exchanges 18 and 19 perform heat exchange between the compression space 17A and the expansion space 17B and the heat radiation unit 2 and the heat absorption unit 3, respectively.

A balance mass 29 is attached to the rear side of the casing 30 via a plate panel 28. The balance mass 29 is a mass member that absorbs the vibration of the casing 30 caused by the vibration of the piston 14 and the displacer 15. Specifically, when the piston 14 is vibrated in the casing 30 due to the vibration of the displacer 15, this case is used. As the balance mass 29 vibrates so as to follow the vibration of the single 30, the vibration of the Stirling refrigerator 4 is reduced.

Next, the operation of this Stirling refrigerator 4 will be described.

First, the linear motor 23 is operated to drive the piston 14. The piston 14 driven by the linear motor 23 approaches the displacer 15 and compresses the working medium (working gas) in the compression space 17A.

When the piston 14 approaches the displacer 15, the temperature of the working medium in the compression space 17 A rises, but the heat generated in the compression space 17 A is released to the outside by the heat radiating unit 2. Therefore, the temperature of the working medium in the compression space 17A is maintained almost isothermal. That is, this process corresponds to an isothermal compression process in a reverse Stirling cycle.

[0079] After the piston 14 approaches the displacer 15, the displacer 15 moves to the heat absorbing portion 3 side. On the other hand, the working medium compressed in the compression space 17A by the piston 14 flows into the regenerator 16, and further flows into the expansion space 17B. At that time, the heat of the working medium is stored in the regenerator 16. In other words, this process corresponds to an isovolumetric cooling process in a reverse Stirling cycle.

[0080] The high pressure working medium that has flowed into the expansion space 17B has the displacer 15 on the piston 14 side.

It expands by moving to (rear side). Thus, as the displacer 15 moves rearward, the center portion of the displacer spring 25 is deformed so as to protrude rearward.

[0081] As the working medium expands in the expansion space 17B as described above, the temperature of the working medium in the expansion space 17B decreases, but heat from the outside is transferred to the expansion space 17B by the heat absorbing portion 3. Therefore, the inside of the expansion space 17B is kept almost isothermal. That is, this process corresponds to the isothermal expansion process of the reverse Stirling cycle.

Thereafter, the displacer 15 starts to move in a direction in which the piston 14 also moves away. As a result, the working medium in the expansion space 17B passes through the regenerator 16 and returns to the compression space 17A side again. At that time, since the heat stored in the regenerator 16 is given to the working medium, the temperature of the working medium rises. In other words, this process is equivalent to a constant volume heating process in a reverse Stirling cycle. To do.

[0083] By repeating this series of processes (isothermal compression process, isothermal cooling process, isothermal expansion process, isothermal heating process), an inverse Stirling cycle is configured. As a result, the endothermic portion 3 is gradually lowered in temperature and has an extremely low temperature (for example, about −50 ° C.). On the other hand, the heat dissipating part 2 gradually becomes hot (eg about 60 ° C). As described above, the cold heat in the heat absorption part 3 is supplied into the refrigerator through the low-temperature side circulation circuit, and the heat in the heat dissipation part 2 goes outside the refrigerator through the first and second high-temperature side circulation circuits. Released.

As described above, according to the embodiment of the present invention, it is planned from the beginning to appropriately combine the features of each embodiment described above. Further, it should be considered that the embodiment disclosed this time is illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

Industrial applicability

[0085] As described above, the present invention is applied to a piezoelectric pump and a Stirling cooler.

Claims

The scope of the claims

[1] a casing (32) formed by joining a plurality of metal members;

A piezoelectric element (36) that partitions the space in the casing (32) into first and second internal spaces (34, 34A, 34B, 35);

A piezoelectric pump provided between the casing (32) and the piezoelectric element (36) and having first and second non-metallic internal parts (33A, 33B) for holding the piezoelectric element (36) .

[2] The first and second inner parts (33A, 33B) are made of grease.

The first and second internal parts (33A, 33B) define the outer peripheries of the first and second internal spaces (34, 35), respectively;

The piezoelectric pump according to claim 1, wherein the piezoelectric element (36) is held so as to sandwich the piezoelectric element (36) between the first and second internal parts (33A, 33B).

[3] The working medium formed on the first internal part (33A) and facing the first internal space (34) as a working space for the suction pipe (41) outside the casing (32) passes. The entrance (37),

An outlet part (38) formed on the first internal part (33A), through which the working medium directed to the discharge pipe (42) outside the casing (32) force of the first internal space (34) passes, A first check valve (39) installed between the inlet (37) and the first inner space (34); and between the outlet (38) and the first inner space (34). A second check valve (40) installed, a gap between the first and second internal spaces (34, 35) and the piezoelectric element (36), the inlet part (37) and the outlet part A plurality of O-rings (43) for sealing gaps between the casing (32) and the casing (32), respectively.

The first internal part (33A) includes first and second check valve installation portions where the first and second check valves (39, 40) are installed, and the plurality of O-rings (43). 2. The piezoelectric pump according to claim 1, further comprising a plurality of grooves that are respectively installed.

[4] The second internal space (35) as the back pressure space and the inlet portion (37) or the outlet portion (3

8) further comprising a communication part (44) for communicating with

The piezoelectric pump according to claim 3, wherein the communication portion (44) is configured by a hole or a groove formed in the first and second internal parts (33A, 33B).

[5] The piezoelectric pump according to claim 3, further comprising a communication hole (44) for communicating the inlet portion (37) or the outlet portion (38) with a joint portion of the metal member.

[6] First suction pipe (41A) force formed on the first internal part (33A) and external to the casing (32). Force is applied to the first internal space (34A) as a working space. A first inlet (37A) passing through;

A working medium formed on the second internal part (33B) and directed toward the second internal space (34B) as a second working pipe (41B) force working space outside the casing (32) passes therethrough. The second entrance (37B),

A first outlet portion formed on the first internal part (33A) and through which the working medium that passes through the first internal space (34A) force and directed toward the first discharge pipe (42A) outside the casing (32) (38

A) and

A second outlet portion formed on the second internal part (33B) through which the working medium passes from the second internal space (34B) to the second discharge pipe (42B) outside the casing (32). (38

B) and

First and second check valves (39A, 39B) installed between the first and second inlet portions (37A, 37B) and the first and second internal spaces (34A, 34B), respectively; ,

Third and fourth check valves (40A, 40B) installed between the first and second outlet portions (38A, 38B) and the first and second inner spaces (34A, 34B), respectively. ,

A gap between the first and second internal spaces (34A, 34B) and the piezoelectric element (36), the first and second inlet portions (37A, 37B), and the first and second outlet portions ( 38A, 38B) and a plurality of O-rings (43) each sealing a gap between the casing (32),

A first to a fourth check valve installation portion in which the first to fourth check valves (39A, 39B, 40A, 40B) are respectively installed on the first and second internal parts (33A, 33B); 2. The piezoelectric pump according to claim 1, further comprising a plurality of grooves in which the plurality of O-rings (43) are respectively installed.

[7] A communication hole (44A) is provided for communicating the first or second inlet portion (37A, 37B) or the first or second outlet portion (38A, 38B) with the joint portion of the metal member. Claim A piezoelectric pump according to claim 6 in the range.

[8] A working medium formed on the first internal part (33A) and facing the first internal space (34A) as a working space for the suction pipe (41) outside the casing (32) passes. The first entrance (37A),

A second inlet part (37B) formed on the second inner part (33B), through which the first inlet part (37A) force passes a directional force working medium into the second inner space (34B);

A first outlet portion (38A) formed on the first internal part (33A) and through which the working medium passing through the first internal space (34A) force and the casing (32) is directed to the discharge pipe (42) outside the casing (32A). ) And a second outlet part (38B) formed on the second inner part (33B), through which a directional working medium passes from the second inner space (33B) to the first outlet part (38A),

A first communication part (44B), which is constituted by a hole or a groove formed in the first and second internal parts (33A, 33B) and communicates the first and second inlet parts (37A, 37B);

A second communication part (44C) constituted by a hole or a groove formed in the first and second internal parts (33A, 33B) and communicating the first and second outlet parts (38A, 38B);

[9] The piezoelectric pump (6) according to claim 1 is provided in the working medium circulation circuit on the high temperature side. Stirling refrigerator.