JP2006308135A - Stirling engine and stirling cooling storage - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stirling engine and a stirling cooling storage superior in workability and having a pressure adjusting mechanism free from excessive lowering of operating efficiency of the engine. <P>SOLUTION: A piston 14 has a communication passage for communicating a working space and a back pressure space. The communication passage includes an internal space 140 formed inside of the piston 14, an opening portion 141 reaching the internal space 140 from an end face at a back pressure space side, of the piston 14, and an opening portion 142 reaching the internal space 140 from an end face at a compression space side of the piston 14. A check valve 144 is mounted on the opening portion 141 for inhibiting the flow from the compression space to the back pressure space while permitting the flow from the back pressure space to the compression space. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a Stirling engine and a Stirling Refrigerator / Freezer, and more particularly, to a Stirling engine and a Stirling cooler having a working space and a back pressure space.

  A Stirling engine that obtains low temperature / high temperature or electric power or power by using compression / expansion of a working gas accompanying reciprocation of a piston and a displacer is conventionally known.

  The Stirling engine includes a piston and a displacer that smoothly reciprocates on an inner surface (cylinder sliding surface) of a cylinder provided in the pressure vessel. The piston and the displacer are arranged on the same axis, and a rod forming one end of the displacer passes through a sliding hole provided in the center of the piston. The piston and the displacer are elastically supported by the pressure vessel via a piston support spring and a displacer support spring, respectively.

  The internal space of the pressure vessel is divided into two spaces by the piston. One of the spaces is a working space on the displacer side when viewed from the piston, and the other is a back pressure space on the side opposite to the working space side when viewed from the piston, that is, on the rear end side of the cylinder. These spaces are filled with a working medium.

  The working space is further divided into two spaces by a displacer. One of the spaces is a compression space sandwiched between the piston and the displacer, and the other is an expansion space on the side opposite to the compression space side with respect to the displacer, that is, on the tip side of the cylinder. Note that the compression space and the expansion space are connected via a regenerator.

The piston is driven by a linear motor or the like and reciprocates at a predetermined cycle. Thereby, the working medium is compressed / expanded in the working space. The displacer reciprocates linearly by the pressure change accompanying the compression / expansion of the working medium. At this time, the piston and the displacer reciprocate at the same period with a predetermined phase difference.
JP 2000-39222 A JP 2004-340477 A JP 2004-332675 A

  In the Stirling engine configured as described above, a gas seal is provided between the cylinder sliding surface and the piston sliding surface to block the working space and the back pressure space. However, no matter what gas seal is applied, the working space and the back pressure space cannot be completely blocked, and it is inevitable that the working medium flows through both spaces through a minute gap. Therefore, when the piston is moving in the working space direction, the pressure in the compression space becomes higher than the pressure in the back pressure space, and the working medium flows from the compression space to the back pressure space. Conversely, when the piston moves in the direction of the back pressure space, the pressure in the compression space becomes lower than the pressure in the back pressure space, and the working medium flows from the back pressure space to the compression space. In general, since the volume of the back pressure space is larger than the volume of the compression space, the pressure difference between the compression space and the back pressure space moves in the working space direction rather than when the piston moves in the back pressure space direction. When you are bigger. For this reason, the working medium in the compression space tends to gradually flow out into the back pressure space for each cycle of the reciprocating motion of the piston. As a result, the pressure balance between the back pressure space and the working space is lost, and the amplitude centers of the piston and the displacer may deviate from predetermined positions.

  On the other hand, in the conventional Stirling engine, in order to maintain the pressure balance between the back pressure space and the working space, the cylinder is provided with a first passage connecting the back pressure space and the cylinder sliding surface, A second passage connecting the compression space and the piston sliding surface is provided. The opening of the first passage (cylinder sliding surface side) and the opening of the second passage (piston sliding surface side) are opposed to each other when the piston reaches a preset position. It is arranged.

  However, in the above-described processing for the cylinder and the piston, it takes time to provide the hole, and as a result, the processing cost / processing time increases. Further, the cylinder and the piston are precision parts that require high-precision dimensions, and it is preferable to avoid machining the sliding surface.

  Further, from a viewpoint different from the above, in the pressure adjusting mechanism as described above, the compression efficiency of the piston, and hence the operation efficiency of the Stirling engine, is reduced by the gas flow entering and exiting the second passage provided in the piston.

  The present invention has been made in view of the above problems, and an object of the present invention is a Stirling engine and a Stirling cooling system having a pressure adjusting mechanism that is excellent in workability and does not excessively reduce the operating efficiency of the engine. Is to provide storage.

  In one aspect, the Stirling engine according to the present invention has an outer shell, a cylinder assembled in the outer shell enclosing the working medium, a piston reciprocating in the cylinder, and a reciprocating motion with a phase difference with respect to the piston. A displacer, a compression space formed between the piston and the displacer, a back pressure space formed on the opposite side of the displacer side with respect to the piston, and an opposite side of the piston side with respect to the displacer. The piston has an internal space, a first hole that reaches the internal space from the end surface on the back pressure space side, a second hole that reaches the internal space from the end surface on the compression space side, and an outer peripheral surface. A third hole that reaches the internal space, provided on the first hole and / or the second hole, from the compression space while allowing a flow from the back pressure space to the compression space. Further comprising inhibiting non-return valve a flow towards the inter pressure.

  According to the above configuration, it is possible to obtain a mechanism that maintains the pressure balance between the back pressure space and the working space without excessively increasing the processing cost / processing time and without reducing the operation efficiency of the Stirling engine. Further, since the working medium can be ejected from the internal space toward the sliding surface of the piston / cylinder, a gas bearing structure that holds the piston that reciprocates in the cylinder can be obtained.

  In another aspect, the Stirling engine according to the present invention includes an outer shell, a cylinder assembled in the outer shell enclosing the working medium, a piston reciprocating in the cylinder, and a reciprocating motion with a phase difference with respect to the piston. A displacer, a compression space formed between the piston and the displacer, a back pressure space formed on the opposite side of the displacer side with respect to the piston, and an opposite side of the piston side with respect to the displacer. A communication passage that extends through the cylinder and extends from the compression space to the back pressure space, is provided on the communication passage, and allows a flow from the back pressure space to the compression space while allowing the flow from the compression space to the back pressure space. A check valve is further provided for suppressing a flow toward the pressure space.

  Also with the above configuration, it is possible to obtain a mechanism that maintains the pressure balance between the back pressure space and the working space without excessively increasing the processing cost / processing time and without reducing the operation efficiency of the Stirling engine.

  In yet another aspect, the Stirling engine according to the present invention reciprocates with a phase difference with respect to the outer shell, a cylinder assembled in the outer shell enclosing the working medium, a piston reciprocating in the cylinder, and the piston. A moving displacer, a compression space formed between the piston and the displacer, a back pressure space formed on the opposite side of the displacer side with respect to the piston, and formed on the opposite side of the piston side with respect to the displacer An internal space is formed inside the piston, and the internal space has a first space located on the outer peripheral side of the piston and a second space located on the axial center side of the piston. A suction hole portion that reaches the first space from the end surface on the compression space side of the piston is formed, and the compressed air is compressed from the first space while allowing a flow from the compression space toward the first space. A check valve that suppresses the flow toward is provided on the suction hole, a discharge hole reaching the outer peripheral surface of the piston from the first space is formed, and the working medium sucked into the first space from the suction hole is A first hole is formed from the discharge hole toward the inner peripheral surface of the cylinder and reaches the second space from the end surface on the back pressure space side of the piston, and reaches the second space from the end surface on the compression space side of the piston. A second hole is formed.

  According to the above configuration, the pressure balance between the back pressure space and the working space can be maintained by the movement of the working medium via the second space. Further, since the working medium can be ejected from the first space toward the sliding surface of the piston / cylinder, a gas bearing structure that holds the piston that reciprocates in the cylinder can be obtained.

  The Stirling refrigerator according to the present invention includes the Stirling engine described above. This provides a reliable Stirling cooler in which the pressure balance between the back pressure space and the working space is maintained.

  According to the present invention, the pressure balance between the working space and the back pressure space in the Stirling engine can be maintained without excessively increasing the processing cost / processing time and without lowering the operation efficiency of the Stirling engine.

  Hereinafter, one embodiment of a Stirling engine and a Stirling cooler according to the present invention will be described.

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

  Further, here, a Stirling refrigerator as a Stirling engine and a Stirling refrigerator as a Stirling engine-equipped device equipped with the Stirling refrigerator will be described. However, the Stirling engine is not originally limited to a Stirling refrigerator. For example, it is used also as a generator.

FIG. 1 is a piping system diagram of a Stirling refrigerator according to Embodiments 1 and 2 described later.
As shown in FIG. 1, the Stirling refrigerator 1 includes a Stirling refrigerator 4 (Stirling engine) having a high temperature part 2 and a low temperature part 3, a high temperature side evaporator 5 attached to the high temperature part 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, and the second high temperature side circulation circuit including the high temperature side evaporator 5, the circulation pump 6, the dew prevention pipe 9 and the pipes 2C to 2E ( 2nd circulation circuit) and the low temperature side circulation circuit containing the low temperature side condenser 10 attached to the low temperature part 3, the low temperature side evaporator 11, and the pipes 3A and 3B. The first high temperature side circulation circuit cools the high temperature part 2 of the Stirling refrigerator 4, and the second high temperature side circulation circuit supplies heat to the dew condensation prevention pipe 9. The low temperature side circulation circuit performs heat exchange between the air in the refrigerator and the low temperature part 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 heat generated in the high temperature part 2 can be transferred to the high temperature side condenser 7 by utilizing the natural circulation caused by the evaporation and condensation of the refrigerant. The side condenser 7 is disposed above the high temperature side evaporator 5. Further, in order to adjust the boiling point of the refrigerant, the pressure in the circulation circuit system is adjusted (reduced pressure from atmospheric pressure).

  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 flowing into the pipe 2 </ b> C reaches the circulation pump 6 provided below the Stirling refrigerator 4. The refrigerant discharged from the circulation pump 6 is sent to the dew prevention pipe 9 via the pipe 2D. Here, the refrigerant flowing in the dew condensation prevention pipe 9 is kept at a relatively high temperature by the heat given from the high temperature part 2 of the Stirling refrigerator 4. Therefore, the dew condensation prevention pipe 9 can be arranged in the front opening of the refrigerator to suppress the dew condensation at 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 2E. 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 flow 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 evaporation is performed so that the cold heat generated in the low-temperature part 3 can be transmitted to the low-temperature side evaporator 11 by utilizing natural circulation caused by the evaporation and condensation of the refrigerant. The vessel 11 is disposed below the low temperature side condenser 10. Further, the pressure in the circulation circuit system is adjusted in order to adjust the boiling point of the refrigerant.

  When the Stirling refrigerator 4 is operated, heat generated in the high temperature part 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 low temperature 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.

  With the implementation of the cooling cycle described above, frost forms on the low temperature side evaporator 11. Since a well-known technique can be used for the defrosting method for this frost formation, detailed description will not be given.

  By performing the defrosting described above, defrosted water is generated. The defrost water is guided to the drain pan 12B (evaporating dish) installed at the lower part of the bottom surface of the refrigerator main body through the drain pipe 12A. A fan 12C is provided on the top of the drain pan 12B, and an air flow is formed in the vicinity of the surface of the defrost water accumulated in the drain pan 12B by the fan 12C, and relatively dry air is supplied onto the defrost water. Evaporation of defrost water is promoted.

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

  As shown in FIG. 2, 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 high temperature portion 2, a low temperature 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. 2, the outer shell (outer wall) of the Stirling refrigerator 4 is not constituted by a single container, but is positioned on the back pressure space 27 side and the casing 30 (vessel portion) and on the working space 17 side. The high-temperature part 2, the tube 18A, and the low-temperature 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 low temperature portion 3, an expansion space 17 </ b> B is formed. The compression space 17A is mainly surrounded by the high temperature part 2, and the expansion space 17B is mainly surrounded by the low temperature part 3.

  Between the compression space 17 </ b> A and the expansion space 17 </ b> B, a regenerator 16 in which a film is wound on the outer peripheral surface of the cylinder 13 with a predetermined gap is disposed. Thus, 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, an outer yoke 22 and a coil, 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 by 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.

  The high temperature part 2 is attached to the casing 30 via the base member 30A. The high temperature part 2 and the low temperature part 3 are connected via the tube 18A. On the inner peripheral surfaces of the high temperature part 2 and the low temperature part 3, an internal heat exchanger 18 and an internal heat exchanger 19 are provided, respectively. The internal heat exchangers 18 and 19 perform heat exchange between the compression space 17A and the expansion space 17B and the high temperature part 2 and the low temperature part 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.

  When 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 by the high temperature portion 2 is released to the outside. 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 low temperature part 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.

  When 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 external heat is transferred into the expansion space 17B by the low temperature portion 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 (front side). 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 low temperature part 3 is gradually lowered in temperature and has an extremely low temperature (for example, about −50 ° C.). On the other hand, the high temperature part 2 becomes gradually high temperature (for example, about 60 ° C.). As described above, the cold heat in the low temperature section 3 is supplied into the refrigerator through the low temperature side circulation circuit, and the heat in the high temperature section 2 is released to the outside of the refrigerator through the first and second high temperature side circulation circuits. Is done.

  By the way, although a gas seal is provided between the inner peripheral surface of the cylinder 13 and the outer peripheral surface of the piston 14 to cut off the working space 17 and the back pressure space 27, the working medium passes through a minute gap. Thus, the fluid flows between the working space 17 and the back pressure space 27. Therefore, when the piston 14 is moving in the direction of the working space 17 (the direction of the arrow DR3), the pressure in the compression space 17A becomes higher than the pressure in the back pressure space 27, and the working medium moves from the compression space 17A to the back pressure space 27. And flow. Conversely, when the piston 14 is moving in the direction of the back pressure space 27 (arrow DR4 direction), the pressure in the compression space 17A is lower than the pressure in the back pressure space 27, and the working medium is transferred from the back pressure space 27 to the compression space. Flow to 17A. In the Stirling refrigerator 4, since the volume of the back pressure space 27 is larger than the volume of the compression space 17A, the pressure difference between the compression space 17A and the back pressure space 27 is when the piston 14 moves in the direction of the arrow DR4. Rather than when moving in the direction of the arrow DR3. Therefore, the working medium in the compression space 17 </ b> A flows out into the back pressure space 27 little by little every cycle of the reciprocating motion of the piston 14. On the other hand, the pressure adjustment mechanism according to the first and second embodiments returns the working medium from the back pressure space 27 to the working space 17 and maintains the pressure balance between the working space 17 and the back pressure space 27.

(Embodiment 1)
FIG. 3 is a diagram illustrating the pressure adjustment mechanism according to the first embodiment. With reference to FIG. 3, the pressure adjustment mechanism according to the present embodiment is a pressure adjustment mechanism for maintaining the pressure balance between the working space 17 and the back pressure space 27 in the Stirling refrigerator 4 described above. Here, the piston 14 has a communication path that allows the working space 17 and the back pressure space 27 to communicate with each other. Thereby, the pressure balance between the working space 17 and the back pressure space 27 is maintained.

  The communication path includes an internal space 140 formed inside the piston 14, an opening 141 as a “first hole” reaching the internal space 140 from the end surface of the piston 14 on the back pressure space 27 side, And an opening 142 as a “second hole” that reaches the internal space 140 from the end face on the compression space 17A side.

  The opening 142 is formed by providing an opening in the axial end surface of the piston 14 and then assembling a communication tube 1420 (orifice) into the opening. By doing in this way, it is possible to form an opening with a smaller diameter, and the flow rate of the working medium flowing into the internal space 140 from the compression space 17A or flowing out from the internal space 140 into the compression space 17A. Can be adjusted.

  A check valve 144 that suppresses the flow from the internal space 140 to the back pressure space 27 while allowing the flow from the back pressure space 27 to the internal space 140 is provided on the opening 141. In addition, the valve opening direction of the check valve 144 is an arrow DR144.

  The piston 14 is provided with opening portions 143A to 143D as “third hole portions” that reach the internal space 140 from the outer peripheral surface thereof. The opening portions 143A to 143D constitute a “gas bearing structure” described later. And the opening parts 143A-143D are formed by assembling communication pipes 1430A-1430D (orifices) to the openings after providing holes on the outer peripheral surface of the piston 14, respectively. By doing in this way, an opening part with a smaller diameter can be constituted, and the flow rate of the working medium discharged from the internal space 140 toward the cylinder inner peripheral surface can be adjusted.

  The piston 14 supported by the piston spring 24 reciprocates in the direction of the arrow DR1 in the cylinder 13. When the piston 14 moves in the direction of the arrow DR3 (operating space side), the pressure in the compression space 17A becomes higher than the pressure in the back pressure space 27, and the check valve 144 moves from the internal space 140 to the back pressure space 27. The valve is closed to suppress the flow toward. Then, the working medium flows from the compression space 17 </ b> A into the internal space 140 through the opening 142.

  On the other hand, as shown in FIG. 3, when the piston 14 moves in the direction of the arrow DR4 (back pressure space side), the pressure in the back pressure space 27 becomes higher than the pressure in the compression space 17A, and the check valve 144 is Then, the valve is opened in the direction of the arrow DR144 to allow the flow (arrow DR141) from the back pressure space 27 toward the internal space 140. Then, the working medium flows from the internal space 140 into the compression space 17A through the opening 142 (arrow DR142).

  As described above, the working medium flows from the back pressure space 27 into the compression space 17 </ b> A through the internal space 140 as the piston 14 reciprocates. As described above, the working medium in the compression space 17 </ b> A moves to the back pressure space 27 through the gap between the cylinder 13 and the piston 14 for each cycle of the reciprocating motion of the piston 14. On the other hand, according to the pressure adjustment mechanism according to the present embodiment, the working medium that has moved to the back pressure space 27 can be returned to the compression space 17A. Thereby, the pressure balance between the working space 17 and the back pressure space 27 can be maintained.

  As the piston 14 reciprocates, the working medium is ejected from the internal space 140 to the sliding surfaces of the cylinder 13 and the piston 14 through the opening portions 143A to 143D (arrows DR143A to DR143D). Thereby, the gas bearing structure holding the piston 14 that reciprocates in the cylinder 13 is configured.

  The above contents are summarized as follows. That is, a Stirling refrigerator 4 as a “Stirling engine” having a pressure adjusting mechanism according to the present embodiment includes an outer shell body including a casing 30, a cylinder 13 assembled in an outer shell body enclosing a working medium, A piston 14 that reciprocates within the cylinder 13, a displacer 15 that reciprocates with a phase difference with respect to the piston 14, a compression space 17 </ b> A formed between the piston 14 and the displacer 15, and the piston 14 side with respect to the displacer 15. An expansion space 17B formed on the opposite side of the piston 14 and a back pressure space 27 formed on the opposite side of the displacer 15 with respect to the piston 14 are provided. The piston 14 reaches the internal space 140 from the internal space 140, the opening 141 as the “first hole” reaching the internal space 140 from the end surface on the back pressure space 27 side, and the end surface on the compression space 17 </ b> A side. It has the opening part 142 as a "2nd hole part", and the opening parts 143A-143D as a "3rd hole part" which reaches the internal space 140 from an outer peripheral surface. A check valve 144 that suppresses the flow from the compression space 17 </ b> A to the back pressure space 27 while allowing the flow from the back pressure space 27 to the compression space 17 </ b> A is provided on the opening 141. This check valve may be provided on the opening 142 or may be provided on both of the openings 141 and 142.

  According to the pressure adjustment mechanism according to the present embodiment, the pressure balance between the back pressure space and the working space is maintained without excessively increasing the processing cost / processing time and without reducing the operation efficiency of the Stirling engine. A mechanism can be obtained.

(Embodiment 2)
FIG. 4 is a diagram illustrating a pressure adjustment mechanism according to the second embodiment. Referring to FIG. 4, the pressure adjustment mechanism according to the present embodiment is a modification of the pressure adjustment mechanism according to the first embodiment, and a communication path that communicates working space 17 and back pressure space 27 is a cylinder. 13 is formed. Also by this structure, the pressure balance between the working space 17 and the back pressure space 27 is maintained.

  The communication path is configured by an opening 130 that passes through the cylinder 13 and reaches the back pressure space 27 from the compression space 17A. Further, a check valve 131 is provided on the opening 130 to suppress the flow from the compression space 17A to the back pressure space 27 while allowing the flow from the back pressure space 27 to the compression space 17A. Yes. The valve opening direction of the check valve 131 is an arrow DR131.

  The piston 14 supported by the piston spring 24 reciprocates in the direction of the arrow DR1 in the cylinder 13. When the piston 14 moves in the arrow DR3 direction (working space side), the pressure in the compression space 17A becomes higher than the pressure in the back pressure space 27, and the check valve 131 moves from the compression space 17A to the back pressure space 27. The valve is closed to suppress the flow toward.

  On the other hand, as shown in FIG. 4, when the piston 14 moves in the direction of the arrow DR4 (back pressure space side), the pressure in the back pressure space 27 becomes higher than the pressure in the compression space 17A, and the check valve 131 Then, the valve is opened in the direction of the arrow DR131 to allow the flow (arrow DR130) from the back pressure space 27 toward the compression space 17A.

  In this way, the working medium flows from the back pressure space 27 into the compression space 17A as the piston 14 reciprocates. As a result, as in the first embodiment, the pressure balance between the working space 17 and the back pressure space 27 can be maintained.

  The above contents are summarized as follows. That is, in the Stirling refrigerator 4 as the “Stirling engine” having the pressure adjusting mechanism according to the present embodiment, an opening as a “communication path” that penetrates the cylinder 13 and reaches the back pressure space 27 from the compression space 17A. A portion 130 is formed. A check valve 131 that suppresses the flow from the compression space 17 </ b> A to the back pressure space 27 while allowing the flow from the back pressure space 27 to the compression space 17 </ b> A is provided on the opening 130. .

  According to the pressure adjusting mechanism according to the present embodiment, as in the first embodiment, the back pressure space and the processing cost / processing time are not excessively increased and the operation efficiency of the Stirling engine is not decreased. A mechanism that maintains a pressure balance with the working space can be obtained.

(Embodiment 3)
FIG. 5 is a view showing a pressure adjustment mechanism according to the third embodiment. Referring to FIG. 5, the pressure adjustment mechanism according to the present embodiment is a modification of the pressure adjustment mechanism according to the first embodiment, and similarly to the first embodiment, working space 17, back pressure space 27, It has a communicating path which connects. Thereby, the pressure balance between the working space 17 and the back pressure space 27 is maintained.

  Referring to FIG. 5, in the present embodiment, a partition wall 145 is provided inside piston 14. Thereby, the internal space of piston 14 is divided into main space 140A and subspace 140B.

  A hole 146 as a “suction hole” reaching the main space 140A is provided on the end surface of the piston 14 on the compression space 17A side. A check valve 144A that suppresses the flow from the main space 140A to the compression space 17A while allowing the flow from the compression space 17A to the main space 140A is provided on the hole 146.

  On the outer peripheral surface of the piston 14, a “discharge hole” that reaches the main space 140A is provided. The “discharge holes” are formed by providing openings on the outer peripheral surface of the piston 14 and then assembling communication pipes 1430A to 1430D (orifices) to the openings. By doing in this way, the opening part of a smaller diameter can be comprised, and the flow volume of the working medium discharged toward the cylinder internal peripheral surface from 140 A of main spaces can be adjusted.

  The communication path that allows the working space 17 and the back pressure space 27 to communicate with each other includes the sub space 140B and an opening portion 147 as a “first hole” that reaches the sub space 140B from the end surface of the piston 14 on the back pressure space 27 side. And an opening portion 148 as a “second hole portion” that reaches the sub space 140B from the end surface of the piston 14 on the compression space 17A side. The opening 147 is formed by providing an opening in the axial end surface of the piston 14 and then assembling a communication pipe 1470 (orifice) into the opening. By doing so, it is possible to form an opening with a smaller diameter, and to adjust the flow rate of the working medium flowing from the back pressure space 27 into the sub space 140B. In addition, a check valve 144B that suppresses the flow from the compression space 17A to the sub space 140B while allowing the flow from the sub space 27 to the compression space 17A is provided on the opening 148.

  The piston 14 reciprocates in the direction of the arrow DR1. 6 and 7 are views showing a state in which the piston 14 has moved in the direction of the arrow DR3 (working space side) and in the direction of the arrow DR4 (back pressure space side), respectively.

  Referring to FIG. 6, when the piston 14 moves in the direction of the arrow DR3 (operating space side), the pressure in the compression space 17A becomes higher than the pressure in the back pressure space 27, and the check valve 144A The valve is opened to allow the flow from 17A to the main space 140A (arrow DR146), and the check valve 144B is closed to suppress the flow from the compression space 17A to the sub space 140B. Then, the working medium flows from the compression space 17A into the main space 140A through the opening 146.

  Referring to FIG. 7, when the piston 14 moves in the direction of the arrow DR4 (back pressure space side), the pressure in the back pressure space 27 becomes higher than the pressure in the compression space 17A, and the check valve 144A The valve is closed to suppress the flow from the space 140A to the compression space 17A, and the check valve 144B is opened to allow the flow from the sub space 140B to the compression space 17A (arrow DR148). Then, the working medium flows from the back pressure space 27 into the sub space 140B through the opening 147 (arrow DR147).

  Thus, also in the present embodiment, the working medium flows from the back pressure space 27 into the compression space 17A as the piston 14 reciprocates as in the first embodiment. Therefore, the working medium that has passed through the gap between the cylinder 13 and the piston 14 and moved to the back pressure space 27 can be returned to the compression space 17A. Thereby, the pressure balance between the working space 17 and the back pressure space 27 can be maintained.

  In addition, as the piston 14 reciprocates, the working medium that has flowed into the main space 140A from the opening 146 is directed toward the sliding surfaces of the cylinder 13 and the piston 14 via the communication pipes 1430A to 1430D (orifices). Are ejected (arrows DR143A to DR143D). Thereby, the gas bearing structure holding the piston 14 that reciprocates in the cylinder 13 is configured.

  Here, the flow rate of the working medium flowing into the compression space 17A from the sub space 140B is adjusted so as to substantially match the flow rate of the working medium supplied to the gas bearing structure (gas bearing structure). 5 to 7, the flow rate of the working medium flowing from the sub space 140B into the compression space 17A can be adjusted by the communication pipe 1470 (orifice). Thereby, contact with piston 14 and displacer 15 can be controlled.

  The above contents are summarized as follows. That is, the Stirling refrigerator 4 having the pressure adjusting mechanism according to the present embodiment basically has the same configuration as the Stirling refrigerator 4 having the pressure adjusting mechanism according to the first embodiment. Here, as in the first embodiment, the piston 14 has a communication path that opens to an end surface on the back pressure space 27 side and an end surface on the compression space 17A side. The internal space of the piston 14 is divided into a main space 140A as a “first space” located on the outer peripheral side of the piston 14 and a sub-space 140B as a “second space” located on the axial center side of the piston 14. . And the opening part 146 as a "suction hole part" which reaches the main space 140A from the end surface by the side of the compression space 17A of the piston 14 is formed. A check valve 144A that suppresses the flow from the main space 140A to the compression space 17A while allowing the flow from the compression space 17A to the main space 140A is provided on the opening 146. The piston 14 is provided with communication pipes 1430A to 1430D (orifices) that constitute “discharge holes” that reach the outer peripheral surface of the piston 14 from the main space 140A. Here, the working medium sucked into the main space 140 </ b> A is ejected from the communication pipes 1430 </ b> A to 1430 </ b> D toward the inner peripheral surface of the cylinder 13. Then, a communication pipe 1470 (orifice) is provided that constitutes an opening 147 as a “first hole” that reaches the sub space 140B from the end surface of the piston 14 on the back pressure space 27 side. Furthermore, an opening 148 is formed as a “second hole” that reaches the sub space 140B from the end surface of the piston 14 on the compression space 17A side.

  FIG. 8 and FIG. 9 are diagrams showing modified examples related to the opening 148. Referring to FIG. 8, the opening 148 may be configured by using a communication pipe 1480 (orifice) and a check valve 144B in combination. In this case, the flow rate of the working medium flowing into the compression space 17A from the sub space 140B can be adjusted by the hole diameter of the orifice. When the structure of the opening 148 shown in FIG. 8 is adopted, the opening 147 located on the back pressure space 27 side is formed by providing a minute hole in the piston (without using the communication pipe 1470). can do. In addition, referring to FIG. 9, it is possible to adopt a structure in which opening portion 148 is configured by communication tube 1480 (orifice) and check valve 144B is not provided. In this case, it is possible to adopt a structure in which the opening portion 147 is configured by the communication pipe 1470 and the check valve is not provided on the opening portion 147. By doing in this way, although a slight performance fall arises, the number of check valves installed can be reduced and cost can be reduced.

  According to the pressure adjusting mechanism according to the present embodiment, as in the first embodiment, the back pressure space and the processing cost / processing time are not excessively increased and the operation efficiency of the Stirling engine is not decreased. A mechanism that maintains a pressure balance with the working space can be obtained.

  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. The embodiment disclosed this time should be considered as 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.

It is a piping system diagram of the Stirling cooler according to Embodiments 1, 2, and 3 of the present invention. It is sectional drawing which showed the Stirling refrigerator in the Stirling refrigerator which concerns on Embodiment 1, 2, and 3 of this invention. It is the figure which showed the pressure adjustment mechanism in the Stirling engine which concerns on Embodiment 1 of this invention. It is the figure which showed the pressure adjustment mechanism in the Stirling engine which concerns on Embodiment 2 of this invention. It is the figure which showed the pressure adjustment mechanism in the Stirling engine which concerns on Embodiment 3 of this invention. It is the figure (the 1) which showed the operation state of the pressure adjustment mechanism in the Stirling engine which concerns on Embodiment 3 of this invention. It is FIG. (2) which showed the operation state of the pressure adjustment mechanism in the Stirling engine which concerns on Embodiment 3 of this invention. It is the figure which showed one modification of the pressure adjustment mechanism shown by FIGS. It is the figure which showed the other modification of the pressure adjustment mechanism shown by FIGS.

Explanation of symbols

  1 Stirling cooler, 2 high temperature section, 2A-2E pipe (high temperature side circulation circuit), 3 low temperature 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 fans, 9 Condensation prevention pipe, 10 Low-temperature side condenser, 11 Low-temperature side evaporator, 12 Fan, 12A Drain pipe, 12B Drain pan, 12C Fan, 13 Cylinder, 14 Piston, 15 Displacer, 16 Regeneration , 17 working space, 17A compression space, 17B expansion space, 18, 19 internal 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 Space, 28 Leaf spring, 29 Balance mass, 30 Casing, 30A Base member, 130, 141, 142, 143A, 143B, 143C, 143D Open hole, 131, 144, 144A, 144B Check valve, 140 Internal space, 140A Main space, 140B sub space, 145 partition wall, 146, 147, 148 aperture, 1420, 1430A, 1430B, 1430C, 1430D, 1470, 1480 communication pipe, DR1 piston axial direction, DR2 piston circumferential direction, DR3 working space direction, DR4 Back pressure space direction.

Claims (4)

The outer shell,
A cylinder assembled in the outer shell enclosing the working medium;
A piston that reciprocates within the cylinder;
A displacer that reciprocates with a phase difference with respect to the piston;
A compression space formed between the piston and the displacer;
A back pressure space formed on the side opposite to the displacer with respect to the piston;
An expansion space formed on the opposite side of the piston to the displacer,
The piston includes an internal space, a first hole portion that reaches the internal space from an end surface on the back pressure space side, a second hole portion that reaches the internal space from an end surface on the compression space side, and an inner surface from the outer peripheral surface. A third hole reaching the space,
A check that is provided on the first hole and / or the second hole and suppresses the flow from the compression space to the back pressure space while allowing the flow from the back pressure space to the compression space. A Stirling engine further equipped with a valve. The outer shell,
A cylinder assembled in the outer shell enclosing the working medium;
A piston that reciprocates within the cylinder;
A displacer that reciprocates with a phase difference with respect to the piston;
A compression space formed between the piston and the displacer;
A back pressure space formed on the side opposite to the displacer with respect to the piston;
An expansion space formed on the opposite side of the piston to the displacer,
A communication path that penetrates the cylinder and reaches the back pressure space from the compression space is formed,
A Stirling engine further provided with a check valve provided on the communication path and suppressing a flow from the compression space to the back pressure space while allowing a flow from the back pressure space to the compression space. The outer shell,
A cylinder assembled in the outer shell enclosing the working medium;
A piston that reciprocates within the cylinder;
A displacer that reciprocates with a phase difference with respect to the piston;
A compression space formed between the piston and the displacer;
A back pressure space formed on the side opposite to the displacer with respect to the piston;
An expansion space formed on the opposite side of the piston to the displacer,
An internal space is formed inside the piston,
The internal space has a first space located on the outer peripheral side of the piston and a second space located on the axial center side of the piston,
A suction hole that reaches the first space from the end surface of the piston on the compression space side is formed, and the flow from the compression space toward the first space is allowed while moving toward the first space. A check valve for suppressing flow is provided on the suction hole,
A discharge hole portion reaching the outer peripheral surface of the piston from the first space is formed,
The working medium sucked into the first space from the suction hole is ejected from the discharge hole toward the inner peripheral surface of the cylinder,
A first hole reaching the second space from the end surface on the back pressure space side of the piston is formed,
A Stirling engine in which a second hole reaching the second space from an end surface of the piston on the compression space side is formed.   A Stirling cooler comprising the Stirling engine according to any one of claims 1 to 3.

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