JP3949135B2 - Piezoelectric pump and Stirling refrigerator - Google Patents

Description

  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 cooler including the piezoelectric pump.

  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. With reference 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. 6. 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 has a pressure in the back pressure space 135. A back pressure hole 135A for adjustment is provided. 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.

  When the 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 broken line 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 fluctuates, and the pressure in the working space 134 fluctuates according to the deformation state of the piezoelectric element 136 to suck / discharge the medium.

  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, a force opposite to the direction of movement of the piezoelectric element 136 is obtained. As a result, the operation efficiency of the piezoelectric pump 106 decreases. On the other hand, a back pressure hole 135 </ b> A is provided on the back pressure space 135 side of the casing 132 so that the pressure in the back pressure space 135 is constant regardless of the deformation state of the piezoelectric element 136.

  Moreover, as what applied the heat exchange by a reverse Stirling cycle to a refrigerator, what was described in Unexamined-Japanese-Patent No. 2003-50073 (conventional example 1) etc. are mentioned, for example.

  In Conventional Example 1, the high temperature part for radiating the compression heat of the working gas due to the reverse Stirling cycle to the outside, the low temperature part for absorbing the expansion heat of the working gas due to the reverse Stirling cycle from the outside, and the heat at the low temperature part A low-temperature side circulation circuit comprising a closed circuit in which a low-temperature side condenser and a plurality of low-temperature side evaporators connected to form a thermosyphon are connected to each other, and a low-temperature heat transfer medium that conveys cold heat in a low-temperature part A Stirling refrigeration system is disclosed that is enclosed in a side circulation circuit. Here, the heat in the high temperature part is radiated by the high temperature side heat exchange cycle (heat radiation 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 conveyed and released by the thermosiphon principle.

In the registered utility model No. 2505727 (conventional example 2), a casing, a piezoelectric vibrator provided inside the casing, and a suction and a discharge cylinder provided in a pump chamber on one side of the piezoelectric vibrator. A piezoelectric pump with a check valve is disclosed. In this piezoelectric pump, the pump chamber communicates with the anti-pump chamber located on the opposite side of the pump chamber with respect to the piezoelectric vibrator.
JP 2003-50073 A Registered Utility Model No. 2505727

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

  In the piezoelectric pump as shown in FIG. 6, the casing is configured 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 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 not solved even by the piezoelectric pump shown in the second conventional example.

  In addition, since the piezoelectric element used in the piezoelectric pump has low heat resistance, there is a problem of how to make it difficult to transmit the welding heat to the piezoelectric element when joining the plurality of members by welding in order to improve sealing performance. It becomes. 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 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.

In one aspect, a piezoelectric pump according to the present invention includes a casing formed by welding a plurality of metal members by welding, a piezoelectric element that partitions a space in the casing into first and second internal spaces, and a plurality of Provided between the casing and the piezoelectric element so as to separate the casing and the piezoelectric element so that welding heat during welding of the metal member can be suppressed from being transmitted to the piezoelectric element, and holds the piezoelectric element. First and second internal parts made of metal , the first and second internal parts are made of resin, the first and second internal parts define the outer peripheries of the first and second internal spaces, respectively; The piezoelectric element is held so as to sandwich the piezoelectric element between the first and second internal parts.

By joining a plurality of metallic member constituting the casing by welding, it is possible to improve the durability against leakage of the working medium. 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.

Further, using a forming mold is carried out easily resin, and, by holding the piezoelectric element with a simple structure can be manufactured a piezoelectric pump at low cost.

In another aspect, the 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, and the casing and the piezoelectric element. The non-metallic first and second internal parts that hold the piezoelectric element, and are formed on the first internal parts, from the suction pipe outside the casing toward the first internal space as the working space An inlet portion through which the working medium passes, an outlet portion formed on the first internal part and through which the working medium from the first inner space toward the discharge pipe outside the casing passes, and between the inlet portion and the first inner space A first check valve installed; a second check valve installed between the outlet portion and the first internal space; a gap between the first and second internal spaces and the piezoelectric element; and an inlet portion And the gap between the outlet and the casing, respectively Obtain Bei a plurality of O rings Lumpur. Here, the first internal components, Ru provided first and the first and second check valves are installed respectively and the second check valve installation portion, and a plurality of grooves in which a plurality of O-rings are respectively installed .

  In this configuration, by providing a recess or groove in an internal part made of resin, it is possible to easily form an installation base or groove in which a check valve and an O-ring are provided.

  Here, a communication portion that communicates the second internal space as the back pressure space with the inlet portion or the outlet portion is further provided, and the communication portion is configured by a hole or a groove formed in the first and second internal parts. It is preferable.

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

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

In still another aspect, the 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. Non-metallic first and second internal parts that are provided between the elements and hold the piezoelectric element, and are formed on the first internal parts, and the first internal as a working space from the first suction pipe outside the casing A first inlet portion through which the working medium toward the space passes, and a second inlet portion formed on the second internal part, through which the working medium from the second suction pipe outside the casing toward the second inner space as the working space passes. And a first outlet portion formed on the first internal part, through which the working medium from the first internal space toward the first discharge pipe outside the casing passes, and formed on the second internal part, from the second internal space Outside the casing A second outlet portion through which the working medium toward the second 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; Third and fourth check valves respectively installed between the first and second outlet portions and the first and second internal spaces; a gap between the first and second internal spaces and the piezoelectric element; obtain Bei a plurality of O-rings for each seal a gap between the first and second inlet portions and first and second outlet portion and the casing. Here, in the first and second internal parts, first to fourth check valve installation portions where the first to fourth check valves are respectively installed, and a plurality of groove portions where a plurality of O-rings are respectively installed the Ru provided.

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

  It is preferable to provide a communication hole for communicating the (first and second) inlet portion or the (first and second) outlet portion and the joint portion of the metal member.

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

In still another aspect, the 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. Non-metallic first and second internal parts that are provided between the elements and that hold the piezoelectric element, and are formed on the first internal parts, from the suction pipe outside the casing to the first internal space as the working space Formed on the first inlet part through which the working medium heading and the second internal part are formed, and on the first inner part through the second inlet part through which the working medium from the first inlet part toward the second internal space passes The first outlet portion through which the working medium directed from the first inner space toward the discharge pipe outside the casing passes, and the working medium that is formed on the second inner part and passes from the second inner space toward the first outlet portion pass through. The second outlet, the first and the first A first communication part constituted by a hole or groove formed in the internal part and communicating the first and second inlet parts, and a first and second part constituted by a hole or groove formed in the first and second internal parts. A second communicating portion for communicating the outlet portion, first and second check valves respectively installed between the first and second inlet portions and the first and second internal spaces, and the first and second outlets Third and fourth check valves respectively installed between the first portion and the first and second internal spaces, a gap between the first and second internal spaces and the piezoelectric element, and first and second inlets obtain Bei a plurality of O-rings for each seal a gap between the parts and the first and second outlet portion and the casing. Here, in the first and second internal parts, first to fourth check valve installation portions where the first to fourth check valves are respectively installed, and a plurality of groove portions where a plurality of O-rings are respectively installed the Ru provided.

  In this configuration, both sides of the piezoelectric element can be used as working spaces. Further, the first and second communication portions can be formed without providing a communication pipe outside the casing. Furthermore, by providing a recess or groove in an internal part made of resin, an installation table or groove on which a check valve or an O-ring is provided can be easily formed. As a result, a compact piezoelectric pump that efficiently circulates fluid is provided at low cost.

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

  Moreover, you may further provide the other O-ring which seals a 1st communication part or a 2nd communication part in the joint surface of a 1st internal component and a 2nd internal component. Thereby, the airtightness of the 1st and 2nd communicating part used as the channel | path of a working medium is securable.

  Note that the plurality of metal members constituting the casing may each have a flange portion, and the casing may be formed by welding tip 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 high-temperature side working medium circulation circuit.

  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.

  Embodiments of a piezoelectric pump and a Stirling cooler according to the present invention will be described below with reference to FIGS.

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

  Moreover, in this specification, although the Stirling refrigerator as a Stirling engine mounting apparatus provided with the Stirling refrigerator is demonstrated, the Stirling engine mounting apparatus provided with the piezoelectric pump according to the present invention is limited to the Stirling refrigerator. It is not a thing. The Stirling engine is also used as a generator, for example.

(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 first to third embodiments of the present invention to be described later is provided in a working medium circulation circuit on a high temperature side.

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

Water (H ₂ O) 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 line 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 that generates an air flow in the vicinity of the high-temperature side condenser 7 is provided. The condensed refrigerant returns to the high temperature side evaporator 5 through the pipe 2B (high temperature side return pipe). In the first high temperature side circulation circuit, the high temperature side condenser 7 has a high temperature so that the heat generated in the heat radiating section 2 can be transferred using the natural circulation caused by the evaporation and condensation of the refrigerant. It is arranged above the 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 </ b> C is connected to the lower part of the high temperature side evaporator 5. Liquid phase refrigerant flows from the high temperature side evaporator 5 into the pipe 2C. The refrigerant that has flowed into the pipe 2C reaches the circulation 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 prevention pipe 9 through the pipe 2E. Here, the refrigerant flowing in the dew condensation prevention pipe 9 is kept at a relatively high temperature by the heat given from the heat radiating unit 2 of the Stirling refrigerator 4. Therefore, the dew condensation prevention pipe 9 can be disposed on the front surface of the refrigerator to suppress dew condensation on the door portion or the like. The refrigerant that has flowed through the dew condensation 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.

  Carbon dioxide, hydrocarbons, and the like are sealed as 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 through the pipe 3A (low temperature side conduit). Heat exchange is performed by evaporating the refrigerant in the low temperature side evaporator 11. In order to promote this heat exchange, a fan 12 that generates an air current in the vicinity of the low-temperature evaporator 11 is provided. After the heat exchange, the gasified refrigerant returns to the low temperature side condenser 10 through the pipe 3B (low temperature side return pipe). In the low-temperature side circulation circuit, the low-temperature side evaporator 11 is thus condensed on the low-temperature side so that the cold generated in the heat-absorbing unit 3 can be transmitted using the natural circulation caused by the evaporation and condensation of the refrigerant. It is arranged below the vessel 10. In order to adjust the boiling point of the refrigerant, the pressure in the circulation circuit system is adjusted (substantially reduced in vacuum).

  When the Stirling refrigerator 4 is operated, the 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 warmed airflow from the inside of the refrigerator is sent again to the vicinity of the low-temperature side evaporator 11 and repeatedly cooled.

(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). Non-metallic internal parts 33A and 33B (first and third parts) that are provided between the piezoelectric element 36 that partitions the back pressure space 35 (second internal space) and between the casing 32 and the piezoelectric element 36 and holds the piezoelectric element 36. Second internal parts).

  The internal parts 33A and 33B are made of a resin that can be easily processed and molded. The internal component 33A defines the outer periphery of the working space 34 (pump chamber), and the internal component 33B defines the outer periphery of the back pressure space 35. By making the internal components 33A and 33B face each other, a recess is formed between the internal components 33A and 33B, and the piezoelectric element 36 is received and held in the recess. That is, the internal components 33A and 33B hold the piezoelectric element 36 with the piezoelectric element 36 interposed therebetween.

  In the example of FIG. 2, formed on the internal part 33A and formed on the internal part 33A, an inlet part 37 through which a working medium from the inlet pipe 41 (suction pipe) outside the casing 32 toward the working space 34 passes. A check valve 39 (first check valve) installed between the outlet portion 38 through which the working medium passes from the space 34 toward the outlet pipe 42 (discharge pipe) outside the casing 32 and the inlet portion 37 and the working space 34. ), A check valve 40 (second check valve) installed between the outlet portion 38 and the working space 34, a gap between the working space 34 and the back pressure space 35 and the piezoelectric element 36, and an inlet A plurality of O-rings 43 that seal the gaps between the portion 37 and the outlet portion 38 and the inner surface of the casing 32 are provided. Here, the installation bases (first and second check valve installation portions) on which the check valves 39 and 40 are respectively installed and the groove portions on which the respective O-rings 43 are attached are previously processed into the internal parts 33A and 33B. Is provided.

  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 a 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 portion 44, a communication portion that allows the back pressure space 35 and the outlet portion 38 to communicate with each other may be provided.

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

  In the said structure, durability with respect to the leak of a working medium can be improved by joining the several member which comprises the casing 32 by welding. As a result, the piezoelectric pump 6 that can be used for a long period of time in a closed system in a negative pressure / positive pressure state is provided. Also, resin internal parts 33A and 33B 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 piezoelectric. Transmission to the element 36 can be suppressed. Therefore, the operation efficiency of the piezoelectric element 36 is improved, and as a result, the circulation efficiency of the working medium is improved.

  In addition, by using resin parts that can be easily molded as the internal parts 33A and 33B and holding the piezoelectric element 36 with a simple structure as described above, the piezoelectric pump 6 can be manufactured at low cost. it can.

  Moreover, the installation base and groove | channel in which the non-return valves 39 and 40 and the some O-ring 43 are each provided can be easily formed by providing a recessed part and a groove | channel in resin-made internal components 33A and 33B.

  Furthermore, by forming the communication portion 44, the pressure in the working space 34 (first internal space) and the back pressure space 35 (second internal space) can be kept substantially 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 and holes in the resin internal parts 33A and 33B. As a result, the compact structure of the piezoelectric pump 6 is realized at low cost. Moreover, the communication part 44 can be used as a leak check hole (communication hole) of a casing by making the communication part 44 communicate with the welding location of several 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 tip portions of the flange portion 46. By providing the flange portion 46, the welded portion and the piezoelectric element 36 can be further away. Therefore, the effect of suppressing heat input to the piezoelectric element 36 can be further enhanced.

(Embodiment 2)
FIG. 3 is a sectional view showing the piezoelectric pump according to the second embodiment.

  The piezoelectric pump 6 according to the present embodiment is a modification of the piezoelectric pump 6 according to the first embodiment, and is characterized in that both sides of the piezoelectric element 36 are used as pump chambers (operating spaces 34A and 34B). .

  As shown in FIG. 3, the piezoelectric pump 6 is formed on an internal part 33A (first internal part), and enters the working space 34A (first internal space) from the inlet pipe 41A (first suction pipe) outside the casing 32. An inlet portion 37A (first inlet portion) through which the working medium heading passes and an inner part 33B (second inner part) are formed on the inlet pipe 41B (second suction pipe) outside the casing 32 to provide a working space 34B (first 2, an operation is formed on the internal part 33 </ b> A and is directed from the working space 34 </ b> A to the outlet pipe 42 </ b> A (first discharge pipe) outside the casing 32. An outlet 38A (first outlet) through which the medium passes and an outlet pipe 42B (second discharge pipe) formed on the internal part 33B and outside the casing 32 from the working space 34B. Check valve 39A, 39B (first and second check valves) installed between the outlet part 38B (second outlet part) through which the working medium heading passes and the inlet parts 37A, 37B and the working spaces 34A, 34B, respectively. Valve), check valves 40A and 40B (third and fourth check valves) installed between the outlet portions 38A and 38B and the working spaces 34A and 34B, the working spaces 34A and 34B and the piezoelectric element 36, respectively. 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 (first to fourth check valve installation portions) on which the check valves 39A, 39B, 40A, and 40B are respectively installed and the groove portions to which the respective O-rings 43 are attached The parts 33A and 33B are provided by processing in advance.

  The piezoelectric pump 6 has leak check holes 44A (communication holes) in the internal parts 33A and 33B that reach the inner surface of the casing 32 from the inlet portions 37A and 37B and communicate with the welded portions of the plurality of metal members. The leak check hole 44A may be provided only in one of the internal parts 33A and 33B, or 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 is made of a plurality of metal. A leak check hole that communicates with the welded portion of the 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 time in a closed system in a negative pressure / positive pressure state is provided at low cost.

  Further, 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.

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

(Embodiment 3)
FIG. 4 is a cross-sectional view showing a piezoelectric pump according to the third embodiment.

  The piezoelectric pump 6 according to the present embodiment is a modification of the piezoelectric pump 6 according to the first embodiment, and is characterized in that both sides of the piezoelectric element 36 are used as pump chambers (operating spaces 34A and 34B). .

  As shown in FIG. 4, the piezoelectric pump 6 is formed on the internal part 33 </ b> A (first internal part) and operates from the inlet pipe 41 (suction pipe) outside the casing 32 toward the working space 34 </ b> A (first internal space). An inlet 37A (first inlet) through which the medium passes and an inlet formed on the internal part 33B (second internal part) and through which the working medium from the inlet 37A toward the working space 34B (second internal space) passes. A part 37B (second inlet part), and an outlet part 38A (first outlet part) formed on the internal part 33A through which the working medium from the working space 34A toward the outlet pipe 42 (discharge pipe) outside the casing 32 passes. The outlet part 38B (second outlet part) formed on the internal part 33B through which the working medium from the working space 34B toward the outlet part 38A passes, and the holes or holes formed in the internal parts 33A and 33B An inlet communication portion 44B (first communication portion) that is configured by a groove and communicates the inlet portions 37A and 37B, and an outlet or groove that is formed in the internal parts 33A and 33B and communicates the outlet portions 38A and 38B. 44C (second communication portion), check valves 39A and 39B (first and second check valves) respectively installed between the inlet portions 37A and 37B and the working spaces 34A and 34B, and an outlet portion Check valves 40A and 40B (third and fourth check valves) installed between 38A and 38B and the working spaces 34A and 34B, and gaps between the working spaces 34A and 34B and the piezoelectric element 36, and A plurality of O-rings 43 are provided to seal the gaps between the inlet portions 37A and 37B and the outlet portions 38A and 38B and the inner surface of the casing 32, respectively. Here, the installation base (first to fourth check valve installation portions) on which the check valves 39A, 39B, 40A, and 40B are respectively installed and the groove portions to which the respective O-rings 43 are attached The parts 33A and 33B are provided by processing in advance.

  Here, the inlet communication portion 44B reaches the inner surface of the casing 32 and communicates the welded portions of the plurality of metal members. Thereby, the inlet communication part 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 part 44B may be sealed, and the outlet communication part 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 by the O-ring, so that the inlet portions 37A and 37B and the outlet portions 38A and 38B serving as the working medium passages are formed. Can be prevented from communicating with each other.

  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 time in a closed system in a negative pressure / positive pressure state is provided at low cost.

  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 and holes in the resin internal parts 33A and 33B. As a result, a compact structure of the piezoelectric pump 6 is realized.

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

(Explanation about Stirling refrigerator)
An example of the structure of the 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, and includes a casing 30, a cylinder 13 assembled to the casing 30, and a reciprocating motion in the cylinder 13. Piston 14 and displacer 15, regenerator 16, working space 17 including a compression space 17 </ b> A and an expansion space 17 </ b> B, a heat radiating portion 2, a heat absorbing portion 3, a linear motor 23 as a piston driving means, and a piston spring 24, a displacer spring 25, a displacer rod 26, and a back pressure space 27.

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

  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 divide the working space 17 in the cylinder 13 into a compression space 17 </ b> A and an expansion space 17 </ b> B. 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 the displacer 15 and the heat absorbing portion. 3, an expansion space 17 </ b> B is formed. The compression space 17 </ b> A is mainly surrounded by the heat radiating part 2, and the expansion space 17 </ b> B is mainly surrounded by the heat absorption part 3.

  Between the compression space 17A and the expansion space 17B, a regenerator 16 in which a film is wound with a predetermined gap on the inner peripheral surface of the tube 18A is disposed. The compression space 17A and the expansion space 17B communicate with each other. Thereby, a closed circuit is formed in the Stirling refrigerator 4. The working medium sealed 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 includes 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.

  One end of the piston 14 is connected to a piston spring 24 constituted by a leaf spring 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 leaf spring 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 toward the back pressure space 27 of the piston 14 (hereinafter sometimes referred to as the rear).

  A back pressure space 27 surrounded by a casing 30 is disposed on the opposite side of the piston 14 from the displacer 15. 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. There is also a working medium 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 exchangers 18 and 19 perform heat exchange between the compression space 17A and the expansion space 17B and the heat radiating unit 2 and the heat absorbing unit 3, respectively.

  A balance mass 29 is attached to the rear side of the casing 30 via a leaf spring 28. The balance mass 29 is a mass member that absorbs vibration of the casing 30 that is generated when the piston 14 and the displacer 15 vibrate. Specifically, when the vibration is generated in the casing 30 due to the vibration of the piston 14 or the displacer 15, the balance mass 29 is vibrated so as to follow the vibration of the casing 30, whereby the Stirling refrigerator 4. Vibration is reduced.

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

  First, the linear motor 23 is actuated 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.

  As the piston 14 approaches the displacer 15, the temperature of the working medium in the compression space 17 </ b> A rises, but heat generated in the compression space 17 </ b> 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.

  After the piston 14 approaches the displacer 15, the displacer 15 moves to the heat absorption unit 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. That is, this process corresponds to an isovolumetric cooling process in a reverse Stirling cycle.

  The high-pressure working medium that has flowed into the expansion space 17B expands when the displacer 15 moves to the piston 14 side (rear side). As the displacer 15 moves rearward in this way, the center portion of the displacer spring 25 is also deformed so as to protrude rearward.

  As described above, when the working medium expands in the expansion space 17B, the temperature of the working medium in the expansion space 17B decreases, but external heat is transferred into the expansion space 17B by the heat absorbing unit 3, The inside of the expansion space 17B is kept almost isothermal. That is, this process corresponds to an isothermal expansion process of a reverse Stirling cycle.

  Thereafter, the displacer 15 starts to move away from the piston 14. Thereby, the working medium in the expansion space 17B passes through the regenerator 16 and returns to the compression space 17A side again. At this time, since the heat stored in the regenerator 16 is applied to the working medium, the working medium is heated. That is, this process corresponds to a constant volume heating process of a reverse Stirling cycle.

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

  Although the embodiments of the present invention have been described above, it is planned from the beginning to appropriately combine the characteristic portions of the respective embodiments described above. Moreover, it should be thought that embodiment disclosed this time is an illustration and restrictive at no points. 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.

It is an example of the piping system diagram of a Stirling refrigerator. It is sectional drawing of the piezoelectric pump which concerns on Embodiment 1 of this invention. It is sectional drawing of the piezoelectric pump which concerns on Embodiment 2 of this invention. It is sectional drawing of the piezoelectric pump which concerns on Embodiment 3 of this invention. It is an example of the sectional side view which showed the Stirling refrigerator in the Stirling refrigerator. It is sectional drawing of the conventional piezoelectric pump.

Explanation of symbols

  1 Stirling refrigerator, 2 heat dissipating section, 2A to 2F pipe (high temperature side circulation circuit), 3 heat absorption section, 3A, 3B pipe (low temperature side circulation circuit), 4 Stirling refrigerator, 5 high temperature side evaporator, 6 circulation pump, 7 High-temperature side condenser, 8 fan, 9 Dew prevention pipe, 10 Low-temperature side condenser, 11 Low-temperature side evaporator, 12 Fan, 13 Cylinder, 14 Piston, 15 Displacer, 16 Regenerator, 17 Working space, 17A Compression space, 17B expansion space, 18, 19 heat exchanger, 18A tube, 20 inner yoke, 21 movable magnet, 22 outer yoke, 23 linear motor, 24 piston spring, 25 displacer spring, 26 displacer rod, 27 back pressure space, 28 leaf spring 29 Balance mass, 30, 32 Casein 33A, 33B internal parts, 34, 34A, 34B working space, 35 back pressure space, 36 piezoelectric element, 37, 37A, 37B inlet part, 38, 38A, 38B outlet part, 39, 39A, 39B, 40, 40A, 40B check valve, 41, 41A, 41B inlet pipe, 42, 42A, 42B outlet pipe, 43 O-ring, 44 communicating portion, 44A leak check hole, 44B inlet communicating portion, 44C outlet communicating portion, 45 power supply terminal, 46 flange Department.

Claims (7)

A casing formed by welding a plurality of metal members by welding;
A piezoelectric element that partitions the space in the casing into a first and a second internal space;
Provided between the casing and the piezoelectric element so as to separate the casing and the piezoelectric element so that welding heat during welding of the plurality of metal members can be suppressed from being transmitted to the piezoelectric element. A non-metallic first and second internal parts for holding the piezoelectric element ,
The first and second internal parts are made of resin;
The first and second internal parts define outer peripheries of the first and second internal spaces, respectively;
A piezoelectric pump that holds the piezoelectric element so as to sandwich the piezoelectric element between the first and second internal components . A casing formed by joining a plurality of metal members;
A piezoelectric element that partitions the space in the casing into a first and a second internal space;
Non-metallic first and second internal parts provided between the casing and the piezoelectric element and holding the piezoelectric element;
An inlet portion that is formed on the first internal part and through which a working medium is directed from the suction pipe outside the casing toward the first internal space as a working space;
An outlet portion formed on the first internal part and through which a working medium from the first internal space toward a discharge pipe outside the casing passes;
A first check valve installed between the inlet and the first internal space;
A second check valve installed between the outlet portion and the first internal space;
A plurality of O-rings that seal the gap between the first and second internal spaces and the piezoelectric element, and the gap between the inlet and the outlet and the casing, respectively.
The first internal part is provided with first and second check valve installation portions on which the first and second check valves are installed, and a plurality of grooves on which the plurality of O-rings are installed, respectively. , Piezoelectric pump. A communication portion for communicating the second internal space as a back pressure space with the inlet portion or the outlet portion;
The piezoelectric pump according to claim 2 , wherein the communication portion is configured by a hole or a groove formed in the first and second internal parts. A casing formed by joining a plurality of metal members;
A piezoelectric element that partitions the space in the casing into a first and a second internal space;
Non-metallic first and second internal parts provided between the casing and the piezoelectric element and holding the piezoelectric element;
A first inlet portion that is formed on the first internal part and through which a working medium is directed from the first suction pipe outside the casing toward the first internal space as a working space;
A second inlet part formed on the second internal part, through which a working medium that passes from the second suction pipe outside the casing toward the second internal space as a working space passes;
A first outlet that is formed on the first internal part and through which a working medium from the first internal space toward the first discharge pipe outside the casing passes;
A second outlet portion that is formed on the second internal part and through which a working medium from the second internal space toward the second discharge pipe outside the casing passes;
First and second check valves respectively installed between the first and second inlet portions and the first and second internal spaces;
Third and fourth check valves respectively installed between the first and second outlet portions and the first and second internal spaces;
A plurality of seals for sealing the gap between the first and second internal spaces and the piezoelectric element, the first and second inlet portions, and the gap between the first and second outlet portions and the casing, respectively. With an O-ring
In the first and second internal parts, first to fourth check valve installation portions in which the first to fourth check valves are installed, and a plurality of groove portions in which the plurality of O-rings are installed, respectively. A piezoelectric pump provided with 5. The piezoelectric pump according to claim 2 , wherein a communication hole is provided for communicating the inlet portion or the outlet portion with a joint portion of the metal member. A casing formed by joining a plurality of metal members;
A piezoelectric element that partitions the space in the casing into a first and a second internal space;
Non-metallic first and second internal parts provided between the casing and the piezoelectric element and holding the piezoelectric element;
A first inlet portion formed on the first internal part, through which a working medium from the suction pipe outside the casing toward the first internal space as a working space passes;
A second inlet part formed on the second inner part and through which a working medium from the first inlet part toward the second inner space passes;
A first outlet that is formed on the first internal part and through which a working medium from the first internal space toward a discharge pipe outside the casing passes;
A second outlet portion formed on the second inner part and through which a working medium from the second inner space toward the first outlet portion passes;
A first communicating portion configured by a hole or a groove formed in the first and second internal parts, and communicating the first and second inlet portions;
A second communication part configured by a hole or a groove formed in the first and second internal parts, and communicating the first and second outlet parts;
First and second check valves respectively installed between the first and second inlet portions and the first and second internal spaces;
Third and fourth check valves respectively installed between the first and second outlet portions and the first and second internal spaces;
A plurality of seals for sealing the gap between the first and second internal spaces and the piezoelectric element, the first and second inlet portions, and the gap between the first and second outlet portions and the casing, respectively. With an O-ring
In the first and second internal parts, first to fourth check valve installation portions in which the first to fourth check valves are installed, and a plurality of groove portions in which the plurality of O-rings are installed, respectively. A piezoelectric pump provided with A Stirling cooler in which the piezoelectric pump according to any one of claims 1 to 6 is provided in a working medium circulation circuit on a high temperature side.

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