JP2008002452A - Linear compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a linear compressor reduced in size. <P>SOLUTION: The linear compressor includes a linear motor 20 comprising a cylindrical pressure vessel 4; a pair of electromagnets 21 each disposed outside of the pressure vessel 4; a pair of moving members 10 moving back and forth in the pressure vessel 4 with magnetic fields generated by the electromagnets 21; and a pair of permanent magnets for keeping positions of the moving members 10 in the pressure vessel 4 when the electromagnets 21 are not energized. The linear compressor has a pair of slide members 14 on the respective moving members 10. The slide members 14 slide on an inner circumferential surface 4c of the pressure vessel 4 when the moving members 10 move back and forth in the pressure vessel 4, and define a compression space 2 for compressing an operation gas between the moving members 10 and the pressure vessel 4. The linear compressor also has a pair of thrust generation units 11 disposed in the respective moving members 10. The thrust generation units 11 are made of magnetic material and provide the moving members 10 with thrust using magnetic fields of the electromagnets 21 and the permanent magnets 12. The slide members 14 are disposed outside of the thrust generation units 11 with respect to a radial direction of the pressure vessel 4. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a linear compressor applied to a regenerative refrigerator such as a Stirling refrigerator or a pulse tube refrigerator or a vapor compression refrigerator.

  In recent years, linear compressors that drive pistons with linear motors have high compression efficiency, and have recently been used in Stirling refrigerators, pulse tube refrigerators, and the like. A known linear compressor relating to the present invention is described in Patent Document 1 described later.

  FIG. 10 is a schematic diagram of a linear compressor described in Patent Document 1. The linear compressor 100 is driven by a pair of linear motors 130. Each linear motor 130 includes a first electromagnet 131, a second electromagnet 132, and a movable member 120. The first electromagnet 131 and the second electromagnet 132 are provided outside the cylindrical pressure vessel 110. The movable member 120 is housed inside the pressure vessel 110. A piston portion 121 made of a non-magnetic material is provided on one end side of the movable member 120 in the longitudinal direction. The piston part 121 slides on the inner wall of the pressure vessel 110. The piston 121 defines a working gas compression chamber 101 between the movable member 120 and the pressure vessel 110. The flow path 102 of the compression chamber 101 is connected to a cold storage type refrigerator not shown. On the other end side in the longitudinal direction of the movable member 120, a plunger portion 123 made of a nonmagnetic material to which the permanent magnet 122 is fixed (embedded) is provided. A yoke 124 is provided on both pole sides (N pole / S pole) of the permanent magnet 122. The movable member 120, the first electromagnet 131, and the second electromagnet 132 form a magnetic circuit. The movable member 120 is supported by a support member 140 composed of a plurality of thin plate springs 141. The support member 140 is accommodated in a support case 142 formed in a round pipe shape.

The first electromagnet 131 and the second electromagnet 132 are energized with an alternating current having a frequency close to the natural frequency of the vibration system considering the elastic characteristics of the working gas in the movable member 120, the support member 140, and the pressure vessel 110, and the electromagnet. The direction of attractive and repulsive forces generated between the first electromagnet 131 and the second electromagnet 132 and the permanent magnet 122 embedded in the movable member 120 is periodically reversed to move. The member 120 is reciprocated. By this reciprocation, the working gas in the compression chamber 101 is compressed and expanded.
Japanese Patent No. 3173492

  In the linear compressor 100 described above, the movable member 120 of the linear motor 130 includes a piston part 121 (sliding part) that slides on the inner wall of the pressure vessel 110 to compress the working gas, the first electromagnet 131, and the second electromagnet 131. Plunger portions 123 (thrust generating portions) for generating a thrust on the movable member 120 by the magnetic fields of the electromagnet 132 and the permanent magnet 122 are arranged side by side in the axial direction of the pressure vessel 110. For this reason, it is difficult to reduce the size of the movable member 120 with respect to the axial direction of the pressure vessel 110. As a result, it is difficult to reduce the size of the pressure vessel 110 that houses the movable member 120 and the entire linear compressor 100.

  Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide a linear compressor that can realize downsizing.

  In order to solve the above-mentioned problem, the technical means taken in the present invention is, as described in claim 1, a cylindrical pressure vessel, an electromagnet provided outside the pressure vessel, and the electromagnet A linear member composed of a movable member that reciprocates in the axial direction of the pressure vessel inside the pressure vessel by a generated magnetic field, and a permanent magnet that holds the position of the movable member in the pressure vessel when the electromagnet is not energized. A motor and a movable gas provided on the movable member, which slides on the inner peripheral surface of the pressure vessel when the movable member reciprocates in the pressure vessel, and that operates between the movable member and the pressure vessel. And a sliding portion that defines a compression chamber for compressing the thrust member, and a thrust generating portion that is provided on the movable member and is made of a magnetic material and generates thrust on the movable member by the magnetic field of the electromagnet and the permanent magnet. , The sliding part is the pressure With respect to the radial direction of the vessel, it is that where the structure is provided on the outer side of the thrust generating unit.

  Preferably, as described in claim 2, the permanent magnet is provided on the movable member.

  Preferably, as described in claim 3, the permanent magnet is provided outside the pressure vessel.

  Preferably, as described in claim 4, the movable member is slidably supported on the inner peripheral surface of the pressure vessel via the sliding portion, and the working gas in the compression chamber is compressed. The electromagnet and the permanent magnet may be reciprocated in the pressure vessel by a magnetic field generated by the magnet.

  Preferably, as described in claim 5, the movement is provided inside the pressure vessel and restricts movement of the movable member outside the generation range of the thrust by contacting the movable member in the axial direction. A restriction member may be provided. In this case, the movement restricting member is preferably press-fitted and fixed near the end plate of the pressure vessel.

  According to the present invention, the movable member of the linear motor slides on the inner peripheral surface of the pressure vessel when the movable member reciprocates within the pressure vessel, and the working gas is supplied between the movable member and the pressure vessel. A sliding portion that defines a compression chamber for compression and a thrust generating portion that is made of a magnetic material and generates a thrust force on the movable member by the magnetic field of the electromagnet and the permanent magnet are provided. In the movable member, the sliding portion is provided outside the thrust generating portion with respect to the radial direction of the pressure vessel.

  According to the above structure, in the movable member of the linear motor, the portion for compressing the working gas (sliding portion) and the portion for generating thrust by the magnetic field of the electromagnet and permanent magnet (thrust generating portion) are provided. These are arranged side by side in the radial direction of the pressure vessel. Therefore, the dimension of the movable member can be reduced with respect to the axial direction of the pressure vessel as compared with the case where these portions are arranged side by side in the axial direction of the pressure vessel. As a result, the axial dimension of the pressure vessel that houses the movable member can also be reduced, and the entire linear compressor can be downsized.

(First embodiment)
FIG. 1 is a view showing a first embodiment of a linear compressor 1 according to the present invention, and FIG. 2 is a view showing a MM cross section of FIG. As shown in FIG. 1, the compression chamber 2 of the linear compressor 1 is provided in a pressure vessel 4. The pressure vessel 4 includes a cylindrical cylinder part 4a and end plates 4b fixed to both ends of the cylinder part 4a. A buffer chamber 5 is provided inside the pressure vessel 4. The two buffer chambers 5 communicate with the buffer tank 7 via the pipe 6. The buffer tank 7 is provided outside the pressure vessel 4 in a range within the total length in the axial direction (longitudinal direction) of the pressure vessel 4. The compression chamber 2 in the pressure vessel 4 is connected to the compression chamber 31 of the low temperature generating unit 30 of the Stirling cycle via the pipe 3. The linear compressor 1 compresses and expands the working gas (such as helium gas) in the compression chamber 2 by driving a pair of linear motors 20.

  The linear motor 20 includes an electromagnet 21 as a stator and a columnar movable member 10 having a piston function.

  The electromagnet 21 is provided outside the pressure vessel 4 and includes a coil 22 wound with a copper wire and yokes 24 and 25 made of a magnetic material. The yokes 24 and 25 have outer peripheral portions 24a and 25a and inner peripheral portions 24b and 25b, respectively. The outer peripheral portion 24a and the inner peripheral portion 24b, and the outer peripheral portion 25a and the inner peripheral portion 25b are connected via the radiating portions 24c and 25c, respectively, so that the cross section passing through the A axis is substantially U-shaped. The length in the A-axis direction of the inner peripheral portions 24b and 25b is shorter than the length in the A-axis direction of the outer peripheral portions 24a and 25a. The coil 22 is disposed in a space formed by the outer yoke 24 and the outer yoke 25 so that a copper wire is wound around the outer peripheral sides of the inner peripheral portions 24b and 25b. The coil 22 is arranged so that the magnetic flux flows through the inner peripheral portion 24b of the outer yoke 24 and the inner peripheral portion 25b of the outer yoke 25 when the coil 22 is energized.

  The movable member 10 is accommodated in the pressure vessel 4 and reciprocates in the A-axis direction inside the pressure vessel 4 by a magnetic field generated by the electromagnet 21. The movable member 10 includes a thrust generating part 11, a permanent magnet 12, an adjusting member 13, and a sliding part 14. The thrust generating portion 11 includes a stepped columnar core 11a made of a magnetic material and a core 11b made of a magnetic material fixed to the end of the small diameter portion of the core 11a. The permanent magnet 12 has a cylindrical shape and is inserted into the small diameter portion of the core 11a. For example, the permanent magnet 12 is magnetized such that the outer peripheral surface is an N pole and the inner peripheral surface is an S pole (the outer periphery may be an S pole and the inner periphery may be an N pole). The adjustment member 13 is made of a non-magnetic material, is fixed to the end surface of the core 11b, and is provided to adjust the head clearance between the pair of movable members 10 and 10. If the axial lengths of the movable member 10 and the electromagnet 21 and the mounting position of the electromagnet 21 in the axial direction are accurately determined, the adjusting member 13 may not be provided.

  The sliding portion 14 is provided outside the thrust generating portion 11 with respect to the radial direction of the pressure vessel 4. The sliding portion 14 slides on the inner peripheral surface 4 c of the pressure vessel 4 when the movable member 10 reciprocates in the pressure vessel 4, and compresses the working gas between the movable member 10 and the pressure vessel 4. A compression chamber 2 is defined. As the sliding portion 14, for example, a sliding material 14a made of a resin material containing an additive in PTFE is bonded to the outer peripheral surface of the large diameter portion of the core 11a and the outer peripheral surface of the core 11b, or is baked or coated. Those applied to the outer peripheral surface of the large-diameter portion of the core 11a and the outer peripheral surface of the core 11b are applicable. In the present embodiment, the former is illustrated.

  The outer diameter of the sliding portion 14 is slightly smaller than the inner diameter of the cylinder portion 4 a of the pressure vessel 4, and a minute gap is provided between the outer peripheral surface of the sliding portion 14 and the inner peripheral surface 4 c of the pressure vessel 4. . The minute gap functions as a clearance seal that suppresses leakage during compression and expansion of the working gas in the compression unit 2 to a very small amount, and also serves to smoothly slide the movable member 10 in the pressure vessel 4.

  Next, the relationship between the electromagnet 21 and the thrust generator 11 will be described.

  When the coil 22 is not energized (non-energized), the center of the A-axis direction between the inner peripheral portions 24 b and 25 b of the outer yokes 24 and 25 and the A-axis direction of the permanent magnet 12 are generated by the magnetic force of the permanent magnet 12. Is almost the same as the center. In this case, as shown in FIG. 3A, when the outer peripheral side of the permanent magnet 12 is N and the inner periphery is S pole, the magnetic flux emitted from the outer peripheral side (N pole) of the permanent magnet 12 Through the peripheral portion 24b (25b) and the large diameter portion and the small diameter portion of the core 11a of the thrust generating portion 11, the permanent magnet 12 enters the inner peripheral side (S pole) to form a closed loop B (closed loop C). The magnitudes and flow directions of the magnetic fluxes in the closed loop B and the closed loop C are substantially equal, and the magnetic forces acting on the thrust generating unit 11 are balanced and positioned at the neutral point.

  When the coil 22 is energized in the non-energized state of FIG. 3A, the magnetic flux generated in the coil 22 is affected by the magnetic flux generated by the permanent magnet 12 as shown in FIG. Small diameter part of the core 11a of the part 11, the permanent magnet 12, the inner peripheral part 24b of the outer yoke 24 of the electromagnet 21, the radiating part 24c, the outer peripheral part 24a, the outer peripheral part 25a of the outer yoke 25 of the electromagnet 21, the radiating part 25c, the inner peripheral part The portion 25b passes through the core 11b of the thrust generating portion 11 and returns to the small diameter portion of the core 11a to form a closed loop D. The magnetic flux of the closed loop B shown in FIG. 3A is affected by the magnetic flux generated by the coil 22 (closed loop D), and the flow direction of the closed loop B1 is the same as that of the closed loop B as shown in FIG. It becomes like this. On the other hand, the magnetic flux in the closed loop C shown in FIG. 3A is also affected by the magnetic flux generated by the coil 22 (closed loop D), and the flow direction is the same as the closed loop C1 as in the closed loop C.

  The direction of the axial component of the magnetic flux generated in the gap between the thrust generating portion 11 and the inner peripheral portions 24 b and 25 b of the outer yokes 24 and 25 is the direction of the thrust generated in the thrust generating portion 11. As can be seen from FIG. 3B, the axial components of the gaps of the inner peripheral portions 24b and 25b of the outer yokes 24 and 25 of the magnetic flux B1 and the magnetic flux C1 are substantially zero, and the outer yokes 24 and 25 of the magnetic flux D Since the axial component of the gap portions of the inner peripheral portions 24 b and 25 b is the bottom dead center direction, the thrust generating portion 11 generates a thrust R in the bottom dead center direction, that is, the direction away from the compression chamber 2.

  When the coil 22 is energized in the opposite direction to FIG. 3B in the non-energized state of FIG. 3A, the magnetic flux generated in the coil 22 is changed to that shown in FIG. 3B as shown in FIG. A closed loop E in the opposite direction to the closed loop D shown in FIG. As shown in FIG. 3C, the magnetic fluxes in the closed loop B and the closed loop C in FIG. 3A are the same as the closed loop B2 and the closed loop C2 in the flow direction.

  As can be seen from FIG. 3 (c), the axial components of the gap portions of the inner peripheral portions 24b and 25b of the outer yokes 24 and 25 of the magnetic flux B2 and the magnetic flux C2 are substantially zero, and the outer yokes 24 and 25 of the magnetic flux E. Since the axial component of the gap portions of the inner peripheral portions 24b and 25b is the top dead center direction, the thrust generating portion 11 generates a thrust S in the top dead center direction, that is, the direction toward the compression chamber 2. .

  Accordingly, when a plus / minus alternating current is applied to the coil 22, the movable member 10 reciprocates in the pressure vessel 4, and the working gas in the compression chamber 2 is compressed and expanded.

  Next, the low temperature generating part 30 of the Stirling cycle will be described with reference to FIG.

  The compression chamber 31 formed on the back side of the displacer 35 is in communication with the radiator 32, the regenerator 33, and the expansion chamber 34 in order. A cylinder 38 into which the displacer 35 is inserted is provided on the inner peripheral side of the regenerator 33, and a minute gap is provided between the inner peripheral surface of the cylinder 38 and the outer peripheral surface of the displacer 35. This minute gap seals the working gas in the expansion chamber 34 and the compression chamber 31. One end of a rod 36 is fixed to the back side of the displacer 35. The rod 36 protrudes into the case 40 housing the spring 39, and the working gas in the compression chamber 31 and the case 40 is slidably sealed by a rod seal (not shown) provided in the case 40. Is done. A member 37 that receives the end surface of the spring 39 is fixed to the other end of the rod 36.

  In the compression chamber 2 of the linear compressor 1 and the compression chamber 31 of the low temperature generating unit 30 of the Stirling cycle, the working gas compressed by the movable member 10 and the displacer 35 is cooled by the radiator 32 and flows into the regenerator 33. Cooled by a regenerator material such as a wire mesh, flows into the expansion chamber 34, and the downward movement of the displacer 35 causes the working gas to expand substantially isothermally to generate refrigeration at a lower temperature. As the displacer 34 moves upward, the working gas in the expansion chamber 34 flows into the regenerator 33, where it is heated by the regenerator material, heated up, passed through the radiator 32, and compressed by the movable member 10 and the displacer 35. Suctioned into chamber 2 and compression chamber 31 completes one cycle.

  The resonance frequency of the displacer 35 and the spring 39 is adjusted by the mass of the displacer 35 and the spring constant of the spring 39 so as to substantially match the frequency of the current supplied to the linear motor 20 of the linear compressor 1. Thereby, a large stroke of the displacer 35 can be obtained.

  The frequency of the current applied to the linear motor 20 is the natural frequency of the vibration system in consideration of the movable member 10 of the linear compressor 1, the magnetic spring constant due to the magnetic force of the linear motor 20, and the gas spring constant of the working gas in the pressure vessel 4. Set to a frequency close to. With this setting, the movable member 10 can obtain a large stroke with a small current.

  In general, the gas spring constant is larger than the magnetic spring constant, and the natural frequency of the vibration system of the linear compressor 1 is substantially determined by the gas spring constant and the mass of the movable member 10. This gas spring constant is determined by the pressure fluctuation width of the compression chamber 2 acting on the movable member 10, the pressure fluctuation width of the buffer chamber 5, and the stroke of the movable member 10. The buffer chamber 5 communicates with the buffer tank 7 via the pipe 6, and when the volume of the buffer tank 7 is changed, the pressure fluctuation width of the buffer chamber 5 also changes, so that the gas spring constant can be changed. That is, when the volume of the buffer tank 7 is increased, the pressure fluctuation range of the buffer chamber 5 is reduced, the gas spring constant is also reduced, and the natural frequency of the vibration system of the linear compressor 1 is reduced. When the volume of the buffer tank 7 is reduced, the pressure fluctuation range of the buffer chamber 5 is increased, the gas spring constant is increased, and the natural frequency of the vibration system of the linear compressor 1 is increased. Accordingly, since the buffer tank 7 is disposed outside the pressure vessel 4, the natural frequency of the vibration system of the linear compressor 1 can be easily changed by changing the volume of the buffer tank 7, and a good operating frequency can be easily set. Can be adjusted.

  As shown in FIG. 11, in order to restrict the movable member 10 from moving outside the thrust range of the linear motor 20 (the range in which thrust is generated in the movable member 10), the movement restricting member 4 d is provided inside the pressure vessel 4. It is also possible to provide. The movable member 10 is located within the thrust range of the linear motor 20 in the pressure vessel 4. The movement restricting member 4d is made of a resin material or the like, and is press-fitted and fixed to the inner peripheral surface 4c of the cylinder portion 4a of the pressure vessel 4. For press-fitting and fixing, it is not necessary to use a fastening material such as an adhesive or a screw or a complicated fastening structure, and the cost can be reduced. The movement restricting member 4d has such a shape that a fastening force is generated near the end plate 4b so as not to cause distortion in the cylinder portion 4a when being pressed into the pressure vessel 4, for example, the diameter of the portion close to the end plate 4b is the other portion. It is formed in a larger shape.

  FIG. 12 is a schematic diagram for explaining the operation of the movement restricting member 4d. At the stage where gas replacement, evacuation, and the like have been completed, the movable member 10 stops in contact with the movement restricting member 4d in the axial direction (the state before return). The movable member 10 is within the magnetic force range of the linear motor 20, but when the linear motor 20 is not energized, the magnetic force (magnetic spring) returns the movable member 10 to the center position (reference position, position of the movable member 10 in FIG. 11). However, it is weak and the frictional force works as resistance, so it cannot return naturally. If the movement restricting member 4d is installed at a position closer to the movable member 10 at the central position, the movable member 10 can be naturally returned to the central position by a magnetic force. However, in order to reduce the probability of contact between the movable member 10 and the movement restricting member 4d during normal operation of the linear compressor 1, the movement restricting member 4d should be installed as far as possible with respect to the movable member 10 at the central position. It is advantageous in terms of low vibration and low noise.

  Here, when a current is applied to the linear motor 20 to operate the linear compressor 1, the movement restricting member 4 d and the movable member 10 come into contact with each other for a few seconds in the initial period. Operates and returns to vibrate around the center position (state after return).

  Further, since a resin material is used for the movement restricting member 4d, even if the movement restricting member 4d and the movable member 10 may come into contact with each other during gas replacement or initial current application, the impact applied to the movable member 10 is reduced. .

  As described above, in the linear compressor 1 shown in FIG. 11 in which the movement restricting member 4d is provided, the movable member 10 does not move out of the thrust range of the linear motor 20, so that it relates to gas replacement, evacuation, etc. Time can be significantly reduced and productivity in these operations is improved. Moreover, one of the causes of the failure of the linear compressor 1 is eliminated, and the reliability of the linear compressor 1 is improved.

(Second embodiment)
FIG. 4 is a diagram showing a second embodiment of the linear compressor 1 according to the present invention. A present Example is a modification (movable member 45) of the movable member 10 in FIG. FIG. 5A is an enlarged view of the movable member 45. Members having the same structure and action as the members in the first embodiment have the same names and the same reference numerals.

  The movable member 45 is accommodated in the pressure vessel 4 and reciprocates in the axial direction inside the pressure vessel 4 by the magnetic field generated by the electromagnet 21. The movable member 45 includes a thrust generating portion 46, the permanent magnet 12, the adjusting member 13, and the sliding portion 23. The thrust generating portion 46 includes a stepped columnar core 46a made of a magnetic material, and a core 46b made of a magnetic material fixed to the end of the small diameter portion of the core 46a. The permanent magnet 12 and the adjustment member 13 have the same structure / action as that of the first embodiment.

  The sliding portion 23 is provided outside the thrust generating portion 46 with respect to the radial direction of the pressure vessel 4. The sliding portion 23 slides on the inner peripheral surface 4 c of the pressure vessel 4 when the movable member 45 reciprocates in the pressure vessel 4, and compresses the working gas between the movable member 45 and the pressure vessel 4. A compression chamber 2 is defined.

  The sliding part 23 includes a piston ring 23a and a rider ring 23b. The piston ring 23a is made of a sliding material such as PTFE containing filler, and has a ring shape with step cuts, for example. The piston ring 23a is attached (fitted) to a concave groove 47a formed on the large diameter side of the core 46a and a concave groove 48a formed on the core 46b. The outer peripheral surface of the piston ring 23a is inscribed in the inner peripheral surface of the cylinder portion 4a of the pressure vessel 4, but a gap is provided between the inner peripheral surface of the piston ring 23a and the bottom surfaces of the grooves 47a and 48a. . Therefore, the piston ring 23a has a function of sealing the working gas, but does not have a function of supporting the movable member 45 with respect to the inner peripheral surface of the cylinder portion 4a. In the pressure vessel 4, the sealing performance between the compression chamber 2 and the buffer chamber 5 is maintained by the piston ring 23a. In this embodiment, the piston ring 23a is attached to both the groove 47a and the groove 48a, but it may be attached to only one of them.

  The rider ring 23b has a substantially cylindrical shape (ring shape) made of a sliding material such as PTFE containing filler. The rider ring 23b is attached to (inserted into) a concave groove 47b formed on the large diameter side of the core 46a and a concave groove 48b formed on the core 46b. The inner peripheral surface of the rider ring 23b circumscribes the bottom surfaces of the grooves 47b and 48b, and a minute gap is provided between the outer peripheral surface of the rider ring 23b and the inner peripheral surface 4c of the cylinder portion 4a of the pressure vessel 4. As shown in FIG. 5B, a groove (notch) 23c through which the working gas flows is provided on the outer peripheral surface of the rider ring 23b. Therefore, the rider ring 23b has a function of a bearing that slidably supports the movable member 45 with respect to the inner peripheral surface 4c of the cylinder portion 4a, but does not have a function of sealing the working gas. The movable member 45 smoothly slides on the inner peripheral surface 4c of the cylinder portion 4a of the pressure vessel 4 via the rider ring 23b of the sliding portion 23.

  According to the configuration of the second embodiment, in addition to the operations and effects of the first embodiment, when the wear amount of the outer peripheral surfaces of the piston ring 23a and the rider ring 23b increases due to the long-time operation of the linear compressor 1, There is an effect that these parts can be easily replaced.

(Third embodiment)
FIG. 6 is a diagram showing a third embodiment of the linear compressor according to the present invention. The figure shows a linear compressor 50 including one linear motor 20, one electromagnet 21, and one movable member 10. Members having the same structure and action as the members in the first embodiment have the same names and the same reference numerals.

  In the linear compressor 50, the electromagnet 21 of the linear motor 20 is fixed to the outer peripheral surface of the pressure vessel 54, and the movable member 10 of the linear motor 20 is stored on the inner peripheral surface of the cylinder portion 54 a of the pressure vessel 54. The compression chamber 52 is surrounded by one end side of the pressure vessel 54 and the movable member 10. The sealing property of the working gas in the compression chamber 52 is ensured by the sliding portion 14 of the movable member 10. A buffer chamber 5 is provided on the other end side of the pressure vessel 54. The compression chamber 52 of the linear compressor 50 is connected to the compression chamber 31 of the low temperature generating unit 30 of the Stirling cycle via a pipe 53. The buffer chamber 5 communicates with the buffer tank 7 provided within the range of the axial length (longitudinal direction) of the pressure vessel 54 outside the pressure vessel 54 via the pipe 6.

(Fourth embodiment)
FIG. 7 is a view showing a fourth embodiment (linear compressor 80) of the linear compressor according to the present invention, and FIG. 8 is an NN cross-sectional view of FIG.

  In the linear compressor 80, the linear motor 90 includes an electromagnet 91, permanent magnets 93a and 93b, permanent magnets 94a and 94b, and a movable member 96. The electromagnet 91 is provided outside the cylindrical pressure vessel 81. The electromagnet 91 includes a yoke 92 made of a magnetic material, and coils 95a and 95b wound around the tooth portions 92a and 92b of the yoke 92, respectively. Permanent magnets 93a, 93b and 94a, 94b are fixed to the end surfaces of the teeth portions 92a, 92b, respectively. The teeth portion 92a and the teeth portion 92b are provided at symmetrical positions with respect to the A axis (shown in FIG. 7) of the pressure vessel 81, and the permanent magnets 93a, 94a and the permanent magnets 93b, 94b are also symmetrical with respect to the A axis of the pressure vessel 81. It is provided in the position. The permanent magnets 93 a and 93 b and the permanent magnets 94 a and 94 b are provided outside the pressure vessel 81. Permanent magnet 93a and permanent magnet 94b are magnetized to N pole on the outer peripheral side and S pole on the inner peripheral side, and permanent magnet 94a and permanent magnet 93b are magnetized to S pole on the outer peripheral side and N pole on the inner peripheral side.

  The movable member 96 is accommodated in the pressure vessel 81 and reciprocates in the A-axis direction inside the pressure vessel 81 by a magnetic field generated by the electromagnet 91. The movable member 96 includes a thrust generating part 96a, an adjusting member 96b, and a sliding part 96c. The thrust generating part 96a is a columnar member (core 96a) made of a magnetic material. The adjusting member 96b is made of a nonmagnetic material, is fixed to the end surface of the core 96a (thrust generating portion 96a) on the compression chamber 82 side, and is provided to adjust the head clearance between the pair of movable members 96, 96. As in the first embodiment, if the axial lengths of the movable member 96 and the electromagnet 91 and the axial mounting position of the electromagnet 91 are accurately determined, the adjusting member 96b may not be provided.

  The sliding part 96 c is provided outside the thrust generating part 96 a with respect to the radial direction of the pressure vessel 81. The sliding portion 96 c slides on the inner peripheral surface 81 b of the pressure vessel 81 when the movable member 96 reciprocates within the pressure vessel 81, and compresses the working gas between the movable member 96 and the pressure vessel 81. A compression chamber 82 is defined. As the sliding portion 96c, for example, a sliding material 96d made of a resin material containing an additive in a PTFE base is bonded to the outer peripheral surface of the core 96a, or baking or coating is applied to the outer peripheral surface of the core 96a. Things are applicable. In the present embodiment, the former is illustrated.

  A minute gap is provided between the outer peripheral surface of the sliding portion 96 c and the inner peripheral surface 81 b of the cylinder portion 81 a of the pressure vessel 81. Therefore, for the same reason as in the first embodiment, the sliding portion 96c performs a function of sealing the working gas and smoothly sliding the movable member 96 within the pressure vessel 81.

  The pair of electromagnets 91 is fixed to the outer peripheral side of the pressure vessel 81 at a position that is substantially symmetrical with respect to the flow passage hole 82 a provided in the cylinder portion 81 a that forms the compression chamber 82 of the pressure vessel 81. Correspondingly, the pair of movable members 96 are housed so as to face each other at symmetrical positions with respect to the flow passage hole 82a provided in the cylinder portion 81a, and at positions corresponding to the pair of electromagnets 91 when not energized. The permanent magnets 93a and 94a and the permanent magnets 93b and 94b are held in the A-axis direction by the magnetic force. Further, with respect to the radial direction of the pressure vessel 81, the pair of movable members 96 are supported by the inner peripheral surface 81 b of the pressure vessel 81.

  According to the above-described configuration, since the permanent magnets 93a, 93b and 94a, 94b are provided on the outer peripheral surface of the pressure vessel 81, compared to the case where the permanent magnets 93a, 93b and 94a, 94b are provided on the movable member 96, Although the dimension of the linear motor 90 in the direction orthogonal to the X axis increases slightly by the thickness of the permanent magnet, the dimension of the linear motor 90 does not change in the A axis direction, and the volumes of the permanent magnets 93a, 93b and 94a, 94b increase. As a result, the magnetic energy also increases. Therefore, the thrust generated by the linear motor 90 is increased, the sealed pressure of the linear compressor 80 can be increased, and the amount of refrigeration generated by the refrigeration generating unit 30 is increased. Further, from the viewpoint of the occupied volume of the linear compressor 80, the refrigeration capacity increases as compared with the case where the permanent magnet is provided on the movable member 96. Therefore, the compressor occupancy volume per refrigeration capacity is reduced and linear The compressor 80 can be downsized.

(5th Example)
FIG. 9 is a diagram showing a fifth embodiment of the linear compressor according to the present invention. Members having the same structure and action as the members in the first embodiment have the same names and the same reference numerals.

  In the linear compressor 60, a rod 61 made of a sliding material such as resin is inserted into the inner peripheral surface of the substantially cylindrical movable member 70, and between the outer peripheral surface of the rod 61 and the inner peripheral surface of the movable member 70. Is provided with a minute gap. This minute gap seals the leakage of working gas in the compression chamber 62. The rod 61 is disposed so as to be slidable only in the direction orthogonal to the axis without moving in the axial direction by the end plates 64b provided at both ends of the pressure vessel 64.

  The movable member 70 is accommodated in the pressure vessel 64 and reciprocates in the A-axis direction inside the pressure vessel 64 by a magnetic field generated by the electromagnet 21. The movable member 70 includes a thrust generating part 71, a permanent magnet 72, an adjusting member 73, and a sliding part 74. The thrust generating portion 71 includes a stepped cylindrical core 71a made of a magnetic material, and a cylindrical core 71b made of a magnetic material fixed to the end surface on the small diameter side of the core 71a. At the center of the cores 71a and 71b, holes 71c and 71d into which the rod 61 is inserted are provided. A cylindrical permanent magnet 72 is inserted into the outer peripheral surface on the small diameter side of the core 71a. The adjustment member 73 is made of a non-magnetic material and is provided with a hole 73a through which the rod 61 passes. The adjustment member 73 is provided to adjust the head clearance between the pair of movable members 70 and 70 as in the first embodiment.

  The sliding portion 74 is provided outside the thrust generating portion 71 with respect to the radial direction of the pressure vessel 64. The sliding portion 74 slides on the inner peripheral surface 64 c of the pressure vessel 64 when the movable member 70 reciprocates within the pressure vessel 64, and compresses the working gas between the movable member 70 and the pressure vessel 64. A compression chamber 62 is defined. As the sliding portion 74, for example, a sliding material 74a made of a resin material containing an additive in a PTFE base is bonded to the outer peripheral surface of the large-diameter portion of the core 71a and the outer peripheral surface of the core 71b, or is baked or coated. Can be applied to the outer peripheral surface of the large-diameter portion of the core 71a and the outer peripheral surface of the core 71b. In the present embodiment, the former is illustrated.

  As in the first embodiment, a minute gap is provided between the outer peripheral surface of the sliding portion 74 and the inner peripheral surface 64c of the cylinder portion 64a of the pressure vessel 64, so that the working gas sealing function and the movable member 70 are connected to the cylinder. It has a function of sliding smoothly on the inner peripheral surface 64c of 64a. The working gas in the compression chamber 62 is sealed against the buffer chamber 65 by the sliding portion 74. The movable member 70 slides smoothly on the inner peripheral surface 64 c of the cylinder 64 a of the pressure vessel 64 via the sliding portion 74.

  According to the above configuration, when the maximum volume of the compression chamber 62 and the stroke of the movable member 70 are the same as those in the first embodiment, the outer diameter of the movable member 70 is provided because the rod 61 is disposed at the center of the movable member 70. Is larger than the outer diameter of the movable member 10 of the first embodiment, and the outer diameter of the permanent magnet 72 is also larger than that of the first embodiment. As a result, the volume and surface area of the permanent magnet 72 increase, the magnetic energy increases and the magnetic resistance decreases, the thrust of the linear motor 20 increases, the sealed pressure of the linear compressor 60 can be increased, and the refrigerating capacity Will increase.

  In the first to fifth embodiments, the linear compressor of the present invention is applied to the low temperature generating part of the Stirling cycle. However, the linear compressor may be applied to a vapor compression refrigerator.

  As described above, according to the linear compressor of the present invention (especially when used in a low temperature generating part of a Stirling cycle, a pulse tube refrigerator, and a vapor compression refrigerator), the movable member of the linear motor is movable. When the member reciprocates in the pressure vessel, it slides on the inner peripheral surface of the pressure vessel, and a sliding part that defines a compression chamber for compressing the working gas between the movable member and the pressure vessel, and magnetic There is provided a thrust generating section that is made of a material and generates a thrust on the movable member by the magnetic field of the electromagnet and the permanent magnet. In the movable member of the linear motor, the sliding portion is provided outside the thrust generating portion with respect to the radial direction of the pressure vessel.

  According to the above structure, in the movable member of the linear motor, the portion for compressing the working gas (sliding portion) and the portion for generating thrust by the magnetic field of the electromagnet and permanent magnet (thrust generating portion) are provided. These are arranged side by side in the radial direction of the pressure vessel. Therefore, the dimension of the movable member can be reduced with respect to the axial direction of the pressure vessel as compared with the case where these portions are arranged side by side in the axial direction of the pressure vessel. As a result, the axial dimension of the pressure vessel that accommodates the movable member can be reduced, and the entire linear compressor can be downsized.

  Moreover, by providing the movement restricting member, the time for gas replacement or the like can be shortened, productivity is improved, and reliability is improved.

The figure which shows 1st Example of the linear compressor 1 which concerns on this invention. MM sectional drawing of FIG. The magnetic flux line diagram in the linear motor 20 of FIG. The figure which shows 2nd Example of the linear compressor 1 which concerns on this invention. The figure which shows 2nd Example of the linear compressor 1 which concerns on this invention. The figure which shows 3rd Example of the linear compressor which concerns on this invention. The figure which shows 4th Example of the linear compressor which concerns on this invention. NN sectional drawing of FIG. The figure which shows 5th Example of the linear compressor which concerns on this invention. The schematic diagram of a well-known linear compressor. The figure which shows the linear compressor 1 in which the movement control member 4d was provided. The schematic diagram for demonstrating the effect | action of the movement control member 4d.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,80 Linear compressor 2,82 Compression chamber 4,81 Pressure vessel 4c, 81b Inner peripheral surface 4d Movement control member 10,45,96 Movable member 11,46,96a Thrust generating part 12 Permanent magnet 14,23,96c Sliding Moving part 20, 90 Linear motor 21, 91 Electromagnet 93a, 93b Permanent magnet 94a, 94b Permanent magnet

Claims (6)

A cylindrical pressure vessel;
An electromagnet provided outside the pressure vessel; a movable member that reciprocates in the axial direction of the pressure vessel inside the pressure vessel by a magnetic field generated by the electromagnet; and the movable in the pressure vessel when the electromagnet is not energized. A linear motor composed of a permanent magnet that holds the position of the member;
Provided on the movable member, when the movable member reciprocates within the pressure vessel, it slides on the inner peripheral surface of the pressure vessel and compresses the working gas between the movable member and the pressure vessel. A sliding part defining a compression chamber for
A thrust generating section provided on the movable member, made of a magnetic material, and generating a thrust on the movable member by a magnetic field of the electromagnet and the permanent magnet;
With
The linear compressor according to claim 1, wherein the sliding portion is provided outside the thrust generating portion with respect to a radial direction of the pressure vessel.   The linear compressor according to claim 1, wherein the permanent magnet is provided on the movable member.   The linear compressor according to claim 1, wherein the permanent magnet is provided outside the pressure vessel.   The movable member is slidably supported on the inner peripheral surface of the pressure vessel via the sliding portion, and the pressure is generated by a magnetic field generated by the electromagnet and the permanent magnet to compress the working gas in the compression chamber. The linear compressor according to claim 1, wherein the linear compressor reciprocates within the container.   2. A movement restricting member that is provided inside the pressure vessel and restricts the movable member from moving outside the thrust generation range by contacting the movable member in an axial direction. The linear compressor described in 1.   The linear compressor according to claim 5, wherein the movement restricting member is press-fitted and fixed near the end plate of the pressure vessel.

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