JP2004353563A - Linear compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a linear compressor which is low in vibrations and noise, and small in leakage loss when used as a GM type compressor. <P>SOLUTION: A movable cylinder 4 and a movable piston 5 are disposed facing each other, and reciprocated with the phases opposite to each other. The forces to be applied to an outer wall of a linear compressor as the reaction force are canceled by each other when the movable part is put into motion, and a linear compressor of low vibration and low noise can be obtained. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a configuration of a linear compressor, and particularly to a low-vibration / low-noise linear compressor useful for a small-sized pulse tube refrigerator or the like.
[0002]
[Prior art]
Conventionally, a Stirling refrigerator and a GM refrigerator have been used as refrigerating methods of refrigerating to obtain cold by reciprocating motion of compression and expansion of a working fluid without using a phase change of a refrigerant, targeting a relatively low temperature. I have. These are characterized by the difference in pressure vibration source. The GM type generally uses a rotary compressor to constitute high and low pressure sources, and generates pressure fluctuations in the refrigerator by switching valves. On the other hand, in a Stirling refrigerator, pressure oscillation is directly generated in the refrigerator by a piston reciprocating in a cylinder. Both types have a piston called a displacer that controls the movement of the working fluid in the system separately from the pressure vibration source.The heat flow is generated by compressing and expanding the working fluid while reciprocating inside the regenerator. Is occurring. Therefore, control of the pressure and displacement of the working fluid greatly contributes to the refrigeration capacity.
[0003]
In recent years, in this regenerative refrigerator, a pulse tube refrigerator has been remarkably developed in which a hollow tube called a pulse tube is provided instead of a displacer and a gas piston generated therein is used. This pulse tube refrigerator does not require a displacer, which is a movable mechanism, in the refrigeration unit, and thus has features such as a simple structure and low vibration.
[0004]
The pulse tube refrigerator was discovered in the 1960's, and the first generation of the basic type was simply a closed end at the end of the pulse tube, so the phase difference between the pressure fluctuation and the displacement described above was small. The refrigeration capacity was smaller than that of the GM refrigerator and was not suitable for practical use. Subsequently, in the 1980s, a second-generation orifice type was provided with an orifice and a buffer tank at the end of the pulse tube, so that a larger phase difference could be controlled, and practical application was promoted. Furthermore, since then, a number of methods called third generations that can control the phase over a wider range have been proposed and reached today.
[0005]
In a Stirling type pulse tube refrigerator, a linear compressor in which a piston in a cylinder is directly driven by a linear motor is generally used from the viewpoint of miniaturization. However, a linear compressor using a single piston has a problem that pulsating vibration is generated with the movement of the piston, so that it cannot be used for applications that dislike vibration. In addition, there has been a problem that noises are generated and mechanical life is shortened due to the vibration. As a method for solving these problems, a method has conventionally been known in which two pistons are arranged to face each other and driven with a phase difference of 180 ° (for example, see Patent Document 1).
[0006]
FIG. 6 is a diagram schematically showing a configuration of a conventional linear compressor described in Patent Document 1. As shown in FIG. In FIG. 6, a compression space 63 is formed by pistons 61A and 61B and a common cylinder 62, and the two pistons 61A and 61B are operated in opposite phases. 64A and 64B are drive units for driving the pistons 61A and 61B. A suction pipe 65 and a discharge pipe 66 for the working fluid are opened in the compression space 63. As a result, the forces acting on the compressor case due to the movements of the respective pistons 61A and 61B cancel each other, and vibration and noise of the compressor are prevented.
[0007]
Further, in the GM type pulse tube refrigerator, the working fluid sucked / discharged by the compressor can be controlled at an arbitrary timing by opening and closing the valve, so that there is an advantage that the displacement and pressure waveforms can be ideally controlled. However, there is a problem that the refrigerator becomes large because it is necessary to provide a valve in addition to the compressor. As a method for solving this, a method of providing a communication port between a piston and a cylinder has been conventionally known (for example, see Patent Document 2).
[0008]
FIG. 7 is a diagram schematically showing a configuration of a conventional pulse tube refrigerator described in Patent Document 2. In FIG. 7, a linear compressor is housed in a cylindrical outer case, and includes a driving unit 71d for driving a cylinder 71a, a piston 71b, a shaft 71c, a piston 71b, and the like. The cylinder 71a is formed integrally with the outer case, has one end sealed, and is filled with a working fluid. The piston 71b is housed in the cylinder 71a, and the piston 71b, the cylinder 71a, and a sealed end thereof constitute a compression chamber 71e. The piston 71b is provided with a communication passage 71i that communicates the outer periphery of the piston 71b facing the side wall of the cylinder 71a with the compression chamber 71e, and a first passage 72 extending to the outside of the compressor 71 on the side wall of the cylinder 71a; An opening communicating with one end of the second passage 73 is provided so as to be shifted in the movement direction of the piston 71b. When the compressor 71 is operated and the piston 71b is displaced leftward and the pressure in the compression chamber 71e becomes close to the maximum value, the outer peripheral portion of the communication passage 71i and the position of the opening of the first passage 72 coincide with each other, and the compression is performed. A working fluid having a pressure corresponding to the internal pressure of the chamber 71e is delivered. Also, when the piston 71b is displaced rightward and the pressure in the compression chamber 71e becomes close to the minimum value, the outer peripheral portion of the communication passage 71i has the same position as the opening of the second passage 73, and the outer peripheral portion corresponds to the internal pressure. Working fluid at pressure is aspirated. As described above, the discharge and the suction can be switched at a predetermined timing in the same manner as in the compressor unit of the GM type refrigerator.
[0009]
Although FIG. 7 illustrates a single piston, it may be realized by an opposed piston as shown in FIG. 6 to reduce vibration.
[0010]
[Patent Document 1]
JP-A-61-210276 (page 3, FIG. 1)
[Patent Document 2]
JP-A-11-294878 (page 3-4, FIG. 1)
[0011]
[Problems to be solved by the invention]
However, the configuration of FIG. 6 has the following problems. That is, when the diameter and clearance of the cylinder and piston are the same, the longer the sliding distance, the smaller the leakage loss. Considering the case where the same linear compressors are opposed to each other, the length of the compressor is doubled and the leakage between the piston and the cylinder is doubled. If the leakage is to be suppressed equally, the sliding distance of each piston / cylinder needs to be longer, and the overall length of the compressor is longer. That is, this configuration has a problem that the size of the apparatus is increased and the compressor efficiency is reduced.
[0012]
Also, the configuration shown in FIG. 7 has the same problem as described above when an opposing piston is used to reduce vibration. In addition, there are the following problems. That is, the communication passage 71i provided in the piston 71b for suction and discharge is always connected to the compression space, and has a dead volume that does not contribute to compression. That is, there is a problem that the compression ratio is reduced even if the strokes of the piston and the cylinder are the same.
[0013]
The present invention is to solve such a conventional problem, and provides a small-sized, high-efficiency linear compressor with low vibration, and does not cause a reduction in compression ratio when used as a GM type compressor. It is an object to provide a linear compressor.
[0014]
[Means for Solving the Problems]
In order to achieve this object, the linear compressor of the present invention has a configuration in which a movable cylinder and a movable piston are arranged to face each other and reciprocate in opposite phases.
[0015]
With this configuration, the force acting on the outer wall of the compressor as a reaction when the movable portion moves is canceled out, so that a device with low vibration and low noise is obtained, and further, only one side of the compression chamber has a sliding portion. Therefore, a linear compressor having a smaller leakage loss than a structure in which sliding portions are provided on both sides can be obtained.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
According to a first aspect of the present invention, there is provided a casing forming an outer wall of a compressor, a cylinder provided in the casing and slidably supported, and a cylinder provided in the cylinder and having the same axis as a cylinder sliding shaft. A movably supported piston, and a linear drive unit that reciprocates the cylinder and the piston along the sliding axis respectively, each linear drive unit forms a magnetic circuit with the mover and the stator, respectively. It consists of a linear motor that generates thrust, a connecting part that connects the cylinder or piston and the mover, and an elastic body that elastically supports the connecting part with respect to the casing, and reciprocates the cylinder and piston in opposite phases. is there.
[0017]
With the above configuration, the force acting on the casing of the compressor as a reaction of the motion is canceled, and a compressor with low vibration and low noise can be obtained. Furthermore, since only one side of the compression chamber has a sliding portion, leakage loss is reduced as compared with a structure in which both sides are sliding portions.
[0018]
Further, in the inventions according to claims 2 and 3, in addition to the structure of claim 1, at least one of the cylinder and the piston is configured such that a connecting portion with the mover is formed of a flexible rod or a universal joint.
[0019]
With the above configuration, even when the mover and the axis of the cylinder or the piston are arranged or driven with a deviation from each other, the angle of the flexible rod or the universal joint changes to absorb the change. , And can slide smoothly without any contact.
[0020]
According to a fourth aspect of the present invention, in addition to the configurations of the first to third aspects, at least the mass of the movable portion, the equivalent spring constant caused by the compressing action of the elastic body and the working fluid, and the linear force are applied to the cylinder and the piston. This is to make the thrust characteristics of the drive units equal.
[0021]
With the configuration described above, by driving both linear drive units with the same power supply, the amplitude of the cylinder and the piston can be reciprocated with the same amplitude, and the force acting on the casing of the compressor is offset. Can be.
[0022]
According to a fifth aspect of the present invention, in addition to the configuration of the first to third aspects, there is provided a displacement detecting means for detecting a displacement amount of the cylinder and the piston with respect to the casing, respectively. The pistons are operated so as to be equal to each other.
[0023]
With the configuration described above, the reciprocating motion can be performed so that the momentums of the two movable portions become zero in total, and the force acting on the casing of the compressor can be offset.
[0024]
The invention according to Claims 6 and 7 has, in addition to the structure of Claims 1 to 5, a casing provided with a suction flow path and a discharge flow path or a suction discharge flow path through which a fluid to be compressed moves, and provided on a side surface of the cylinder. Is provided with a suction port and a discharge port communicating between the casing side and the compression chamber side, and the compression chamber and the suction flow path or the suction / discharge flow path communicate with each other through the suction port in the vicinity where the volume of the compression chamber becomes maximum. The compression chamber and the discharge flow path or the suction / discharge flow path are configured to communicate with each other via the discharge port in the vicinity where the volume becomes minimum.
[0025]
With the above configuration, it is possible to obtain a linear compressor whose timing can be clearly set so that the suction process is performed at the timing when the pressure in the compression chamber is minimized and the discharge process is performed at the timing when the pressure is maximized. Can be.
[0026]
In addition, the invention according to claim 8 is the same as the constitutions of claims 1 to 5, in addition, the casing is provided with a suction / discharge flow path through which the fluid to be compressed moves, and the side of the cylinder communicates between the casing and the compression chamber. A suction port is provided, and the compression chamber and the suction discharge path are always communicated via the suction port regardless of the volume of the compression chamber.
[0027]
With the above configuration, it is possible to obtain a linear compressor capable of continuously repeating the suction / discharge process.
[0028]
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0029]
(Embodiment 1)
FIG. 1 is a diagram showing a cross section of a linear compressor according to Embodiment 1 of the present invention. First, the overall configuration will be described. The linear compressor 100 is roughly divided into a movable cylinder 4, a movable piston 5, linear motors and elastic bodies 10a and 10b for individually driving the movable cylinder 4, the movable piston 4, a suction / discharge path 22 through which a working fluid flows in and out, and holds the individual parts. And a casing 1 constituting an outer wall.
[0030]
The movable cylinder 4 slidably housed in the cylinder guide 3 connected to the casing 1 has a cylindrical outer shape, has a cylindrical hollow portion having the same axial center as the outer shape, and is compressed together with the end surface of the movable piston 5. A chamber 6 is formed. The movable cylinder 4 and the mover holding member 11a are connected by a flexible rod 12a, and the movable cylinder 4 can be slightly inclined with respect to the mover or the casing 1. The movable piston 5 is the same as the movable cylinder 4 except that the movable piston 5 is slidably disposed on the inner side surface of the movable cylinder 4. The air gap between the sliding surfaces of the movable cylinder 4 and the cylinder guide 3 and the sliding surface of the movable cylinder 4 and the movable piston 5 is a leakage path of the working fluid, and is configured to be 100 microns or less.
[0031]
Note that the movable cylinder 4 and the movable piston 5 are preferably formed of an aluminum material from the viewpoint of weight reduction. By reducing the weight, the rigidity of the elastic body 52 can be reduced as described later. It is also advantageous from the viewpoint of weight reduction to form a resin having sufficient strength and abrasion resistance. Further, the sliding surface may be coated with a fluorine-based resin or the like to reduce sliding loss.
[0032]
Further, the movable cylinder 4 is provided with a suction / discharge port 20 on a side surface thereof, and the compression chamber 6 and the suction / discharge path 22 are always in communication with each other via the communication portion 21 provided on the cylinder guide 3 regardless of the position of the cylinder 4. To do.
[0033]
The linear motor on the movable cylinder 4 side includes a stator 7a and a movable element 9a. The stator 7a is provided on the inner surface side of the casing 1, and is formed by radially laminating a rolled steel plate made of a magnetic material such as a thin electromagnetic steel plate or a silicon steel plate so as to form a U-shaped concave portion on the inner peripheral surface. The coil 8a is mounted in the concave portion of the outer yoke configured as described above. On the other hand, the mover 9a has a permanent magnet on the outer surface side of an inner yoke formed by laminating a rolled steel sheet made of a magnetic material such as a thin electromagnetic steel sheet or a silicon steel sheet in a radial direction parallel to the axis or perpendicular to the axis direction. It is constituted by attaching. The permanent magnet 32 is magnetized so that the magnetic vector is directed in the radial direction. The cylindrical mover 9a is fixed to the outer periphery of the cylindrical mover holding portion 11a. The configuration of the linear motor is the same for the movable piston. Note that 7b is a stator, 8b is a coil, and 9b is a mover.
[0034]
The mover holders 11a and 11b are connected by elastic members 10a and 10b, which support the movers 9a and 9b and the movable cylinder 4 or the movable piston 5 to be able to reciprocate along the axis, by connecting members 13a and 13b. 10a and 10b are fixed to the casing 1 at their peripheral portions. As the elastic body, a leaf spring in which a spiral cutout is provided in a plate-like elastic material is used.
[0035]
Each of the movable cylinder 4 and the movable piston 5 has a natural frequency of a system governed by the mass of each movable portion, the elastic bodies 10a and 10b, and the equivalent spring constant due to the compressive action of the working fluid. In the first embodiment, the thrust characteristics of the linear motor, the mass of the movable portion, and the equivalent spring constant are set to match between the movable cylinder and the movable piston so that the displacement width as well as the natural frequency match. .
[0036]
Next, the operation of the linear compressor configured as described above will be described. Due to the interaction between the magnetic field generated from the permanent magnets constituting the movers 9a and 9b and the magnetic field generated by applying an alternating current to the coils 8a and 8b, the movers 9a and 9b receive a thrust in the axial direction, and The movable piston 5 is driven. By setting the direction of the alternating current flowing through the coils 8a and 8b such that the direction of the thrust acting on the respective movers 9a and 9b is always opposite, the movable cylinder 4 and the movable piston 5 are synchronized with the frequency. Reciprocate in opposite phase. Further, by making the frequency of the alternating current flowing through the coils 8a and 8b substantially coincide with the above-described natural frequency, the operation can be performed while causing resonance.
[0037]
As the movable cylinder 4 and the movable piston 5 reciprocate in the opposite phase in this manner, the volume of the compression chamber 6 increases and decreases, and pressure pulsation is transmitted to the suction / discharge path 22 through the suction / discharge port 20 which is always in communication.
[0038]
FIG. 2 is a schematic diagram of a pulse tube refrigerator using this linear compressor. A working fluid (here, helium is used) is introduced into the regenerator 104 from the compression chamber 6 of the linear compressor 100 via the gas passage 102. A regenerator 104 in which a copper mesh is laminated and a pulse tube 106 formed in a hollow cylinder are connected by being folded back by a cold head 105 as a cooling unit. The cold storage 104 and the end opposite to the cold head of the pulse tube 106 are held by a flange 103, which functions as a flange of a vacuum vessel when the cold head 105 is maintained at a low temperature by vacuum insulation. It also functions as a radiator for heat of the high-temperature gas flowing from the linear compressor 100 and heat flowing from the cold head 105 side. The other end of the pulse tube 106 communicates with the buffer tank 108 via the thin tube 107, and this portion functions as a phase control mechanism for the pressure change and displacement of the working fluid.
[0039]
As described above, according to the first embodiment, the movable cylinder 4 and the movable piston 5 having the same mass can reciprocate in the same stroke and in opposite phases. As a result, the axial force acting on the casing is always cancelled, and a linear compressor and a refrigerator with low noise and vibration during operation can be obtained.
[0040]
Further, since there is only one sliding portion between the movable piston 4 and the movable cylinder 5, a highly efficient linear compressor with less leakage from the compression chamber 6 can be obtained. Furthermore, since the sliding portions of the movable piston 4 and the movable cylinder 5 are overlapped in the radial direction, a small compressor that is short in the sliding axis direction can be configured.
[0041]
In the first embodiment, the movable cylinder 4 and the movable piston 5 are held from one side by the elastic members 10a and 10b. However, the present invention is not limited to this. The same effect can be obtained also in the case where a structure is adopted in which the cylinder or the piston is arranged outside the holding unit.
[0042]
In the first embodiment, a plate-like elastic body is used, but the present invention is not limited to this, and a coil spring or a gas spring may be used.
[0043]
(Embodiment 2)
FIG. 3 is a diagram showing a cross section of a linear compressor according to Embodiment 2 of the present invention. The second embodiment is to realize a linear compressor for use in a GM type pulse tube refrigerator. However, the configuration other than the linear compressor is basically the same as that of the Stirling type. The configuration is the same. Also, the overall configuration of the linear compressor and the basic structure and operation of each part are the same as those in the first embodiment, and therefore only different points will be described.
[0044]
The movable cylinder 4 is provided with a suction port 30 and a discharge port 33 on its side surface, and communicates with a suction path 32 and a discharge path 35 via a suction communication section 31 and a discharge communication section 34 provided on the cylinder guide 3, respectively. . However, the suction port 30 and the suction communication part 31, and the discharge port 33 and the discharge communication part 34 are provided so that the movable cylinder 4 can communicate with the left and right sides in FIG.
[0045]
Next, the operation of the linear compressor configured as described above will be described. Since the movable cylinder 4 and the movable piston 5 reciprocate at the same frequency and in opposite phases to each other, the compression chamber 6 and the suction passage 32 communicate with each other in the vicinity where the volume of the compression chamber 6 is maximum (minimum pressure), and the suction process is performed. Is At this time, the discharge path 35 is closed. Conversely, the compression chamber 6 communicates with the discharge path 35 in the vicinity where the volume of the compression chamber 6 becomes minimum (pressure maximum), and the discharge process is performed. At this time, the suction path 32 is closed.
[0046]
As described above, according to the second embodiment, the movable cylinder 4 and the movable piston 5 having the same mass can reciprocate in the same stroke and in opposite phases. As a result, the axial force acting on the casing is always cancelled, and a linear compressor and a refrigerator with low noise and vibration during operation can be obtained.
[0047]
Further, since there is only one sliding portion between the movable piston 5 and the movable cylinder 4, a compressor with less leakage from the compression chamber 6 and high efficiency can be obtained. Further, since the sliding portion of the movable piston 5 and the sliding portion of the movable cylinder 4 are overlapped in the radial direction, a small compressor that is short in the sliding axis direction can be configured.
[0048]
Further, since the suction process and the compression process can be performed at independent timings, a GM type refrigerator can be realized simply and compactly without using a high / low pressure switching valve or its control device.
[0049]
(Embodiment 3)
FIG. 4 is a diagram showing a cross section of a linear compressor according to Embodiment 3 of the present invention. The third embodiment is to realize a linear compressor for use in a GM type pulse tube refrigerator. The configuration other than the linear compressor is basically the same as that of the Stirling type. The configuration is the same. Also, the overall configuration of the linear compressor and the basic structure and operation of each part are the same as those in the first embodiment, and therefore only different points will be described.
[0050]
The movable cylinder 4 is provided with a suction port 40 and a discharge port 41 on a side surface thereof, and communicates with a suction / discharge path 43 via a suction / discharge communication section 42 provided on the cylinder guide 3. However, the suction port 40 and the discharge port 41 are provided apart from each other in the axial direction such that the movable cylinder 4 communicates near the leftmost and rightmost positions in FIG.
[0051]
Next, the operation of the linear compressor configured as described above will be described. Since the movable cylinder 4 and the movable piston 5 reciprocate at the same frequency and in opposite phases to each other, the compression chamber 6 and the suction / discharge path 43 are connected to the suction port 40 and the suction / discharge path in the vicinity where the volume of the compression chamber 6 is maximum (minimum pressure). The inhalation process is performed by communicating through the communication portion 42. Conversely, the compression chamber 6 and the suction / discharge path 43 communicate with each other through the discharge port 41 and the suction / discharge communication part 42 in the vicinity where the volume of the compression chamber 6 becomes minimum (pressure maximum), and the discharge process is performed.
[0052]
As described above, according to the third embodiment, the movable cylinder 4 and the movable piston 5 having the same mass can reciprocate in the same stroke and in opposite phases. As a result, the axial force acting on the casing is always canceled, and noise and vibration during operation are reduced.
[0053]
Further, since there is only one sliding portion between the movable piston 5 and the movable cylinder 4, a compressor with less leakage from the compression chamber 6 and high efficiency can be obtained. Furthermore, a small compressor that is short in the axial direction can be configured.
[0054]
Further, since the suction process and the compression process can be performed at independent timings, a GM type refrigerator can be realized simply and compactly without using a high / low pressure switching valve or its control device.
[0055]
(Embodiment 4)
FIG. 5 is a diagram showing a cross section of a linear compressor according to Embodiment 4 of the present invention. Since the overall configuration and the basic structure and operation of each part are the same as those in the first embodiment, only different points will be described.
[0056]
In the fourth embodiment, the movable cylinder 4 and the movable piston 5 do not make the mass of the movable portion and the equivalent spring constant by the compressive action of the elastic bodies 10a and 10b and the working fluid individually, but are controlled by these. The natural frequencies of the system. Specifically, based on the shapes of the movable parts of the movable cylinder 4 and the movable piston 5 and the pressure conditions of the working fluid actually applied, the mass of the movable part and the equivalent spring constant due to the compression action are determined. The spring constant of each elastic body is set to match the power supply frequency for driving the linear motor.
[0057]
In addition, a displacement sensor 50a is disposed on the inner surface of the cylinder side shell 2a that extends from the movable cylinder 4 side to seal the casing 1 from the movable cylinder axis. Here, an eddy current type displacement sensor is used, and an aluminum plate 51a serving as a sensor target is attached to the back surface of the elastic body 10a facing the displacement sensor 50a. The same applies to the movable piston side. Thus, the displacement width of the movable cylinder 4 and the movable piston 5 is detected.
[0058]
Next, the operation of the linear compressor configured as described above will be described. Although not shown in FIG. 5, each linear motor on the cylinder side and the piston side is driven by a separate AC power supply capable of voltage control. The alternating current flowing through the coils 8a and 8b has a direction in which the thrusts acting on the respective movers 9a and 9b are always in opposite directions, and their frequencies and phases are made to coincide. Further, a control unit (not shown) for controlling the input voltage to the linear motor from the outputs of the displacement sensors 50a and 50b is provided. The control unit controls the input voltage so that the product of the mass of the movable portion of the movable cylinder 4 and the stroke is equal to the product of the mass of the movable piston movable portion and the stroke.
[0059]
As described above, according to the fourth embodiment, the momentums of the movable portions of the movable cylinder 4 and the movable piston 5 always coincide, and the direction is opposite. Therefore, the momentum of the linear compressor as a whole does not change over time, and a linear compressor with less vibration and noise can be obtained.
[0060]
Further, since there is only one sliding portion between the movable piston 5 and the movable cylinder 4, a highly efficient linear compressor with less leakage from the compression chamber 6 can be obtained. Furthermore, a small compressor that is short in the axial direction can be configured.
[0061]
Further, it is not necessary to intentionally make the masses of the movable portions of the cylinder and the piston having different shapes coincide with each other, so that the degree of freedom in design is increased.
[0062]
In the fourth embodiment, the eddy current type displacement sensors 50a and 50b are used. However, the present invention is not limited to this, and another type of sensor such as an optical sensor may be used.
[0063]
【The invention's effect】
As is apparent from the above description, the present invention reciprocates the movable cylinder and the movable piston in opposite phases with the movable cylinder and the movable piston facing each other.
[0064]
According to this configuration, the force acting on the outer wall of the compressor as a reaction when the movable portion moves is offset, and an effect is obtained that a compressor with low vibration and low noise can be obtained. Further, a reduction in mechanical life due to vibration can be suppressed, and a highly reliable pulse tube refrigerator can be realized.
[0065]
Further, since there is a sliding portion only on one side of the compression chamber, a leakage loss is small and a highly efficient compressor can be obtained as compared with a structure having sliding portions on both sides.
[0066]
Furthermore, since the sliding portions of the piston and the cylinder overlap in the radial direction, a compact compressor that is short in the sliding axis direction can be configured.
[0067]
Further, according to the present invention, at least one of the cylinder and the piston is configured such that a connection portion with the mover is formed of a flexible rod or a universal joint.
According to this configuration, even when the movable element and the axis of the cylinder or the piston are displaced from each other or driven, the connecting means absorbs this, and the piston slides smoothly without any one-side contact. it can. For this reason, the loss of a sliding part can be reduced and efficiency can be improved. In addition, there is a margin in the accuracy of shaft center alignment at the time of assembly, and a compressor excellent in assemblability can be obtained. In addition, since it is less likely to be affected by the displacement of the axis center due to the influence of gravity, the degree of freedom in the arrangement direction of the compressor is increased, and together with the downsizing, it is easy to assemble the apparatus.
[0068]
Further, the present invention is configured such that the mass of the movable portion, the equivalent spring constant resulting from the compression action of the elastic body and the working fluid, and the thrust characteristics of the linear drive portion are equal on the cylinder side and the piston side, and the cylinder and the piston Are made to reciprocate in opposite phase with each other facing each other.
[0069]
According to this configuration, the movable cylinder and the movable piston can reciprocate in the same stroke. As a result, the axial force acting on the outer wall of the compressor is always negated, and a compressor and a refrigerator with low noise and vibration during operation can be obtained.
[0070]
Furthermore, by paying attention only to the direction of the current, both linear motors can be driven by a single AC power supply, and an inexpensive and simple system can be configured.
[0071]
Further, the present invention is to reciprocate in opposite phases by detecting the displacement amplitudes of the cylinder and the piston while opposing each other, so that the product of the displacement amplitude and the mass of the movable part is equal in the cylinder and the piston, respectively. The operation is performed by controlling the drive power supply of each linear drive unit.
[0072]
According to this configuration, the absolute value of the sum of the momentums of the two movable parts can be made zero or extremely small. Thereby, a compressor with less vibration and noise can be obtained.
[0073]
Further, it is not necessary to force the masses of the movable parts of the cylinder and the piston having different shapes to coincide with each other.
[0074]
The present invention also provides a suction port and a discharge port on the side of the cylinder, and the compression chamber communicates with the suction flow path or the suction discharge flow path via the suction port in the vicinity where the volume of the compression chamber is maximized. Since the compression chamber and the discharge channel or the suction / discharge channel are configured to communicate with each other via the discharge port in the vicinity where the volume is minimized, the suction process and the compression process can be performed at independent timing. By using this compressor, a compact and low-vibration GM type refrigerator can be realized without using a high / low pressure switching valve or its control device.
[0075]
Further, the present invention is provided with a suction / discharge port on the side of the cylinder, and is configured to always communicate the compression chamber and the suction / discharge flow path via the suction / discharge port regardless of the volume of the compression chamber. A low-vibration linear compressor capable of repeating the discharging process can be obtained. By using this compressor, a small and low-vibration Stirling type pulse tube refrigerator can be realized.
[Brief description of the drawings]
FIG. 1 is a sectional view of a linear compressor according to a first embodiment of the present invention.
FIG. 2 is a schematic diagram of a pulse tube refrigerator showing the first embodiment of the present invention.
FIG. 3 is a sectional view of a linear compressor according to a second embodiment of the present invention.
FIG. 4 is a sectional view of a linear compressor according to a third embodiment of the present invention.
FIG. 5 is a sectional view of a linear compressor according to a fourth embodiment of the present invention.
FIG. 6 is a schematic diagram showing a configuration of a conventional linear compressor.
FIG. 7 is a schematic diagram showing a configuration of a conventional linear compressor.
[Explanation of symbols]
1 casing
3 Cylinder guide
4 Movable cylinder
5 movable piston
6 compression chamber
7 Stator
8 coils
9 mover
10 Elastic body
11 mover holder
12 Flexible rod
20 Inlet and outlet
21 Communication section
22 Suction and discharge path

Claims (8)

A casing forming an outer wall of the compressor, a cylinder housed in the casing and slidably supported, a piston housed in the cylinder and slidably supported on the same axis as the cylinder sliding shaft; A linear motor that reciprocates a cylinder and a piston along a sliding axis, and each linear drive unit forms a magnetic circuit with a mover and a stator to generate a thrust, A connecting portion for connecting the mover with the cylinder or the piston, and an elastic body for elastically supporting the connecting portion with respect to the casing, wherein the cylinder and the piston are reciprocated in opposite phases. Linear compressor. 2. The linear compressor according to claim 1, wherein at least one of the cylinder and the piston has a connection part with the mover formed of a flexible rod. 3. 2. The linear compressor according to claim 1, wherein at least one of the cylinder and the piston has a joint with a mover formed of a universal joint. 4. The apparatus according to claim 1, wherein at least the mass of the movable part, the equivalent spring constant resulting from the compression action of the elastic body and the working fluid, and the thrust characteristic of the linear drive part are equalized on the cylinder side and the piston side. A linear compressor according to item 1. 4. The apparatus according to claim 1, further comprising: a displacement detecting unit configured to detect a displacement amount of the cylinder and the piston with respect to the casing, wherein the cylinder and the piston are operated such that a product of a displacement amplitude and a mass of the movable unit is equal in the cylinder and the piston. The described linear compressor. The casing has a suction flow path and a discharge flow path through which the fluid to be compressed moves.The side of the cylinder has a suction port and a discharge port communicating the casing side and the compression chamber side, and the vicinity where the volume of the compression chamber is maximized. Wherein the compression chamber and the suction flow path communicate with each other through the suction port, and the compression chamber and the discharge flow path communicate with each other through the discharge port in the vicinity where the volume of the compression chamber is minimized. Item 6. The linear compressor according to any one of Items 1 to 5. 7. The linear compressor according to claim 6, wherein the suction passage and the discharge passage are common. The casing is provided with a suction / discharge flow path through which the fluid to be compressed moves, and the side of the cylinder is provided with a suction / discharge port communicating between the casing side and the compression chamber side. 6. The linear compressor according to claim 1, wherein the compression chamber communicates with the suction / discharge flow path.

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