JPH0610470B2 - Reciprocating compressor and reverse Stirling cycle refrigerator using this compressor - Google Patents

Description

Detailed Description of the Invention TECHNICAL FIELD OF THE INVENTION

The present invention relates to a reciprocating compressor that compresses a working medium by a reciprocating operation of a piston and a configuration of a reverse Stirling cycle refrigerator using the compressor.

[Prior art and its problems]

This type of reciprocating compressor is well known and widely used in refrigerators and various other fields. By the way, in this type of reciprocating compressor, since the piston is linearly reciprocally operated, pulsating vibration is generated as it is, which causes noise and shortens the mechanical life. Come on. For this reason, various anti-vibration measures have been devised conventionally. As a vibration-proof measure, instead of a mechanical crank mechanism, a linear drive system using an electromagnetic solenoid is adopted as the piston drive mechanism, and a vibration absorber is additionally provided to suppress the occurrence of vibration. The scheme is known. Next, the conventional reciprocating compressor described above is shown in FIG. In the drawing, reference numeral 1 is a case of a compressor, and a cylinder 2 in which a compression space for a working medium is formed in the case 1,
Also, a piston 3 inserted in the cylinder 2 is provided, and the piston 3 is reciprocally operated in the cylinder via a drive mechanism 4 such as a solenoid driven linear motor.
Further, a suction valve 7 and a discharge valve 8 are installed on the suction pipe 5 and discharge pipe 6 sides of the working medium which open to the case 1 through the compression space of the cylinder 2. When the piston 3 is reciprocally operated in such a configuration, the volume of the compression space is increased / decreased in accordance with the stroke operation, and accordingly, the working medium sucked through the suction valve 7 is compressed and is discharged through the discharge valve 8. Will be exhaled. A vibration absorber 11 constituted by a mass-spring system in which a mass 9 and a spring 10 are combined is installed on the side surface of the case opposite to the piston 3 with respect to the compressor. The operating principle of such a vibration absorber is well known, and the natural frequency of the vibration absorber system, which is determined by the spring constants of the mass 9 and the spring 10, must be matched with the natural frequency of the main mass excited by the disturbance force. Thus, the vibration amplitude of the main mass excited by the disturbing force can be made zero. However, in the vibration isolation system using such a vibration absorber, there is a resonance frequency region having a large amplitude before and after the natural frequency described above, and the vibration absorber is effective only at the natural frequency of the vibration absorber system. To work. Therefore, this vibration absorber is suitable when the frequency of the disturbance force applied to the main mass is constant, that is, it is suitable for synchronous operation equipment that operates at a constant frequency, but is suitable for other variable speed equipment. Absent. Further, even if the device is operated at a constant frequency, in the process of starting the device, it passes through the region of the resonance frequency described above, so that the resonance vibration applied at this time acts on the device, which is a factor. Problems such as generation of noise and shortening the mechanical life of the equipment are derived.

[Object of the Invention]

The present invention has been made in view of the above points, and it is possible to surely suppress the occurrence of vibration even when the noise driving frequency of the compressor is variable, and thereby to achieve a low and long life cycle. An object of the present invention is to provide a dynamic compressor and a reverse Stirling cycle refrigerator using this compressor.

[Points of the Invention]

In order to configure the above object, according to the present invention, a reciprocating compressor is provided with a cylinder of which both ends are open type in which a compression space of a working medium is formed in a cylinder, and the compression space is sandwiched with respect to the cylinder. A pair of pistons disposed opposite to each other, and a drive mechanism for synchronously reciprocating each piston by setting a phase difference of 180 degrees between the two pistons, the drive mechanism, For each piston, a solenoid coil connected to and supported by the piston shaft, an inner-outer double-layered cylindrical yoke that forms a magnetic path that faces the inner and outer circumferences of the solenoid coil, and the solenoid coil is interposed between the solenoid coil and the yoke. It is composed of a permanent magnet mounted on the fixed side and a fixed side magnet device, and the piston is driven by the electromagnetic force due to the interaction between the alternating current supplied to the solenoid coil and the unidirectional magnetic field generated on the side of the magnet device. With use of the solenoid driven linear motor the reciprocating operation in Linda, it shall constitute the cylinder itself as cylindrical yoke on the inner circumferential side of the solenoid-driven linear motor. Further, a reverse Stirling cycle refrigerator is connected by connecting piping between the compression space in the cylinder of the compressor and the displacer that reciprocates in the expansion cylinder with a predetermined phase difference from the piston operation of the compressor. Shall be configured. With such a configuration, the specifications such as the mass of the movable portion including the piston are set to be the same on both opposing piston sides, so that the force generated on each piston side during operation has the same magnitude and Since the directions are opposite, the reaction forces acting on the compressor case are also equal in magnitude and opposite in direction, and both forces cancel each other out to prevent vibration of the compressor and noise caused by the vibration. Will be done. Further, since the cylinder itself is the cylindrical yoke on the inner peripheral side of the solenoid driven linear motor, the dimension of the compressor in the piston moving direction is shortened.

Examples of the invention

FIG. 1 and FIG. 2 respectively show the structures of different embodiments of the present invention, and the same members as those in FIG. 3 are designated by the same reference numerals. First, in the embodiment of FIG. 1, a cylinder 2 having a compression space 2a for a working medium formed therein is provided in a case 1, and the compression space 2a is provided for the cylinder 2.
A pair of pistons 3A and 3B are arranged opposite to each other on both the left and right sides of the cylinder with the piston in between. The pistons 3A and 3B have the same specifications such as dimensions and mass. Further, a suction pipe 5 and a discharge pipe 6 for the working medium are opened in the case 1 through the center of the cylinder body of the cylinder 2, and a suction valve 7 and a discharge valve 8 are arranged therein as in FIG. On the other hand, the pistons 3A and 3B described above are additionally provided with the following piston drive mechanisms 4A and 4B for reciprocating the respective pistons. That is, the piston drive mechanism includes solenoid coils 14A and 14B wound around a non-magnetic material sleeve 13 installed on the piston shaft 12 for each piston 3A and 3B, and a cylinder located inside and outside facing the solenoid coils 14A and 14B. And a cylindrical permanent magnet 17 interposed between the yokes 15 and 16 that form a magnetic path. Here, the cylinder 2 made of a magnetic material also serves as the yoke on the inner peripheral side. The permanent magnet 17 has its inner and outer peripheral surfaces magnetized into N and S poles. Further, the solenoid coils 14A and 14B described above are arranged such that the winding directions of the coils are opposite to each other, and are connected to an AC power source (not shown) via a connecting terminal 18 of a lead wire. Further, springs 19 are respectively interposed between the pistons 3A and 3B and the left and right end plates of the case 1 to return the pistons 3A and 3B to the neutral position when the compressor is not operating. Next, the operation of the compressor having the above structure will be described. First, on the magnet device side, a magnetic field in a fixed direction is formed in the space between the yokes 15 and 16 in the closed loop magnetic path returning from the N pole of the permanent magnet 17 to the S pole of the magnet through the yokes 15 and 16. Has been done. When an alternating current is passed through the solenoid coils 14A and 14B, an electromagnetic force in the axial direction acts due to the interaction with the magnetic field in the constant direction generated by the magnet device described above according to Fleming's left-hand rule, and this electromagnetic force causes Piston 3A,
3B is driven in the cylinder 2. Further, in this case, since the current supplied to the solenoid coils 14A and 14B is an alternating current, the direction of the electromagnetic force is alternately inverted according to the power supply frequency, and the piston reciprocates left and right alternately. It will be. Moreover, as described above, the solenoid coil 14A
And 14B, the winding directions of the coils are opposite to each other,
Therefore, the pistons 3A and 3B perform stroke operations in opposite directions with a phase difference of 180 degrees. It should be noted that instead of reversing the coil winding directions of the solenoid coils 14A and 14B, the coil currents may be reversed in the same manner, and similarly the pistons 3A and 3B
It is possible to set a phase difference of 180 degrees during each stroke operation. Here, when the piston 3A moves to the left and the piston 3B moves to the right, the volume of the compression space 2a in the cylinder 2 sandwiched between the left and right pistons increases, so that the pressure in this space decreases and the working medium passes through the suction valve 7. Flows into the cylinder. In the next stroke, the movement of the piston is reversed and the piston 3A
When the piston 3B starts moving to the right side and the piston 3B moves to the left side, the volume of the compression space in the cylinder decreases and the pressure in the space rises, and the working medium is discharged outward through the discharge valve 8 in a pressurized and compressed state. Will be done. Moreover, as is clear from the above description of the operation, the pistons 3A and 3B perform a stroke operation with a phase difference of 180 degrees from each other, and the driving force applied to each piston is also the same, so that the reaction force acting on the case 1 is also The magnitudes are the same, and the directions of the forces are opposite due to the phase difference of 180 degrees, and they cancel each other out. Moreover, this operation is performed so that even if the power supply frequency of the compressor is variable, and even when the compressor is started, they cancel each other regardless of these. As a result, it is possible to reliably prevent the vibration of the entire compressor, that is, the vibration and noise propagating outward through the compressor installation base and the case. Next, FIG. 2 shows an embodiment in which an inverse Stirling cycle refrigerator is constructed by combining the compressor described above with a displacer constructed in a separation type expansion cylinder. In FIG. 2, a working medium passage 20 is formed in the case 1 of the compressor so as to communicate with the compression space in the cylinder body of the cylinder 2, and a cooler is provided midway between the passage 20 and the expansion cylinder 21.
It is connected by a pipe 23 equipped with 22. On the other hand, in the expansion cylinder 21, a displacer 26 in which a regenerator 25 composed of a laminated body such as a metal rope is built in a hollow free piston 24 having vent holes at the upper and lower end surfaces is housed and expanded. A cold station 27, which serves as an expansion space for the working medium, is formed between the end of the expansion piston 25 and the top of the cylinder 21. 28 is an expansion piston 24 including the regenerator 25
A mass-spring system together with a spring, and by appropriately selecting the natural vibration frequency of the mass-spring system, the expansion piston 24 is interlocked with the pressure pulsation of the working medium in the system generated by the operation of the compressor. Is reciprocally moved up and down in the expansion cylinder 21 synchronously with the operation of the piston in a predetermined phase difference as shown by the arrow. By operating the compressor by combining the compressor and the displacer as described above, as is well known, the working medium (helium gas or the like) between the in-cylinder compression space on the compressor side and the expansion space on the expansion cylinder 21 side is known. The reverse Stirling cycle in which the refrigerant gas) changes in volume and temperature is
At the cold station 27 on the 21st side, the working medium adiabatically expands to generate refrigeration. Further, in the compressor shown in the embodiment of FIG. 2, structurally, the suction and discharge valves of the compressor shown in FIG. 1 are omitted, and the suction and discharge ports are integrated together, or It has a structure in which one is sealed, and the other structures are the same as those in FIG. Therefore, the generation of vibration and noise during the operation of the compressor can be satisfactorily prevented, and by combining with the free piston type displacer 26 that utilizes the spring resonance force of the spring 28, almost no vibration or noise is generated in the entire equipment. It is possible to obtain a vibration-free and noise-free refrigerator.

【The invention's effect】

As described above, according to the present invention, the following effects are obtained as a result of adopting the above configuration. Vibration generated by the reciprocating motion of a pair of pistons facing each other across the compression space in the cylinder is always canceled out between the pistons regardless of the variable fluctuation of the drive frequency, resulting in no vibration and no noise in the compressor. As a result, the vibration and noise of the refrigerator can be reduced. Since the size of the piston in the moving direction is shortened, the size and weight of the entire device can be reduced.

[Brief description of drawings]

FIG. 1 and FIG. 2 are sectional views showing the construction of different embodiments of the reciprocating compressor according to the present invention, and FIG. 3 is a sectional view showing the construction of a conventional reciprocating compressor. In the figure, 1: compressor case, 2: cylinder, 2a: compression space, 3A,
3B, piston, 4A, 4B: piston drive mechanism, 7: suction valve, 8: discharge valve, 12: piston shaft, 14A, 14B: solenoid coil, 15, 16: yoke forming magnetic path, 17: permanent magnet, 21: Expansion cylinder, 26: Displacer.

Front page continued (72) Inventor Tetsuo Kawasaki 2-2-1 Nagasaka, Yokosuka City, Kanagawa Prefecture Fuji Electric Research Institute Co., Ltd. (72) Inventor Futata Fujinami 2-2-1 Nagasaka, Yokosuka City, Kanagawa Prefecture Fuji Electric Research Institute, Ltd. (56) References Japanese Patent Publication Sho 32-7460 (JP, B1) Actual Publication Sho 49-19447 (JP, Y1)

Claims (4)

[Claims] 1. A cylinder of which both ends are open type, in which a compression space for a working medium is formed in a body, a pair of pistons which are opposed to both sides of the compression space with respect to the cylinder, and a piston of both pistons. A drive mechanism for synchronously reciprocating each piston by setting a phase difference of 180 degrees between them, and as the drive mechanism, a solenoid coil connected and supported to the piston shaft of each piston, A combination with a fixed-side magnet device including an inner-outer double tubular yoke and a permanent magnet interposed between the yokes that form a magnetic path that is arranged to face the inner and outer sides of the solenoid coil. Solenoid-driven linear actuator that reciprocates the piston in the cylinder by the electromagnetic force generated by the interaction between the alternating current supplied to the solenoid coil and the unidirectional magnetic field generated on the magnet side. With use over data, reciprocating compressor, characterized in that the cylinder itself and the inner peripheral side of the cylindrical yoke solenoid driven linear motor. 2. The reciprocating compressor according to claim 1, wherein the solenoid-driven linear motors attached to the pistons are arranged such that the coil winding direction or the current direction of the solenoid coils are opposite to each other. A reciprocating compressor characterized by being set to and operated synchronously with the same AC power source. 3. A reciprocating compressor as set forth in claim 1, wherein a suction valve and a discharge valve for a working medium are installed at a suction port and a discharge port communicating with a central portion of a cylinder body of the cylinder, respectively. A reciprocating compressor characterized by. 4. A cylinder of which both ends are open, in which a compression space for a working medium is formed in a body, a pair of pistons which are opposed to the cylinder on both sides of the compression space, and a pair of pistons of the both pistons. A drive mechanism for synchronously reciprocating each piston by setting a phase difference of 180 degrees between them, and as the drive mechanism, a solenoid coil connected and supported to the piston shaft of each piston, A combination with a fixed-side magnet device including an inner-outer double tubular yoke and a permanent magnet interposed between the yokes that form a magnetic path that is arranged to face the inner and outer sides of the solenoid coil. Solenoid-driven linear actuator that reciprocates the piston in the cylinder by electromagnetic force by the interaction between the alternating current supplied to the solenoid coil and the unidirectional magnetic field generated on the magnet device side. With use of chromatography data, and the cylinder itself reciprocating compressor and the inner peripheral side of the cylindrical yoke solenoid driven linear motor, cylinder compression space,
An inverse Stirling cycle refrigerator, wherein a piston operation of the compressor and a displacer that reciprocates in an expansion cylinder with a predetermined phase difference are connected to each other by piping.