JPS61210276A - Reciprocation type compressor - Google Patents

Abstract

PURPOSE:To solve a problem on vibrations and noises in a compressor, by setting up a pair of pistons at both sides of a cylinder in a way of sandwiching a compression space inside the cylinder, while setting a phase difference of 180 deg. between these pistons, and installing a driving mechanism which makes each piston reciprocate in a synchronous manner. CONSTITUTION:Inside a case 1, there is provided with a cylinder 2 forming a compression space 2a for a working medium in the inner part. And, a pair of positions 3A and 3B setting specifications such as size, quality, quantity, etc., to sameness are set up face-to-face at both symmetrical sides of this cylinder as holding the compression space 2a in between. In addition, a suction pipe 5 and a discharge pipe 6 for the working medium are opened to the case 1 through the center of a barrel of the cylinder 2, and a suction valve 7 and a discharge valve 8 are set up in each of them. Furthermore, each of piston driving mechanisms 4A and 4B is installed in each of these pistons 3A and 3B. Each of these piston driving mechanisms 4A and 4B is constituted of each of solenoid coils 14A and 14B, yokes 15 and 16 and a permanent magnet 17.

Description

[Detailed description of the invention] [Technical field to which the invention pertains]

The present invention relates to the structure of a reciprocating compressor that compresses a working medium by reciprocating a piston.

[Prior art and its problems]

This type of reciprocating compressor is well known and is widely used in refrigerators and other various fields. By the way, in this type of reciprocating compressor, the piston is operated in a linear reciprocating manner, so if left as is, pulsating vibrations will occur during operation, which will cause noise generation and shorten the machine life. To this end, various anti-vibration measures have been devised in the past. As a measure against vibration, a linear drive system using an electromagnetic solenoid, for example, has been adopted instead of a mechanical or rank mechanism for the piston drive mechanism, and a vibration absorber has also been installed to suppress the occurrence of vibration. The method is known. Next, FIG. 3 shows the conventional reciprocating compressor mentioned above. In the figure, l is the case of the compressor, and inside the case 1 is a cylinder 2 which has a compression space for the working medium.
A piston 3 inserted into a cylinder 2 is provided, and the piston 3 is operated to reciprocate within the cylinder via a drive mechanism 4 such as a solenoid-driven linear motor. Further, a suction pipe 5 for the working medium opens into the case 1 and communicates with the compression space of the cylinder 2. A suction valve 7 is provided on each side of the discharge pipe 6. A discharge valve 8 is installed. With this configuration, by reciprocating the piston 3, the volume of the compression space increases or decreases in accordance with the stroke operation, and as a result, the working medium sucked in through the suction valve 7 is compressed and released through the discharge valve 8. You will be spit out. A vibration absorber 11 constituted by a mass-spring system combining a mass 9 and a spring 10 is installed on the side surface of the case of the compressor on the opposite side facing the piston 3. The operating principle of such a vibration absorber is well known; the natural frequency of the vibration absorber system determined by the spring constants of the mass 9 and the spring 10 is made to match the natural frequency of the main mass that is excited by the disturbance force. By doing so, it is possible to reduce the vibration amplitude of the main mass that is excited by the disturbance force to zero.However, in the vibration isolation method using such a vibration absorber, resonance occurs in which the amplitude increases before and after the above-mentioned natural frequency. There is a frequency range, and the vibration absorber acts effectively only at the natural frequency of the vibration absorber system.Therefore, this vibration absorber works only when the frequency of the disturbance force applied to the main mass remains constant, that is, at a constant frequency. Although it is suitable for synchronous operation equipment operated at a constant frequency, it is not suitable for other variable speed equipment.Also, even for equipment operated at a constant frequency, the above-mentioned resonance occurs during the startup process of the equipment. Since the vibration passes through a range of frequencies, the resonant vibrations applied at this time act on the equipment, causing problems such as generation of noise and shortening the mechanical life of the equipment.

[Purpose of the invention] This invention was made in consideration of the above points, and even if the drive frequency of the compressor is variable, vibration generation can always be reliably suppressed, thereby achieving low noise and long life. The purpose is to provide a dynamic compressor. [Key points of the invention]

In order to achieve the above object, the present invention provides a cylinder with both ends open, which forms a compression space for a working medium in the cylinder, and a pair of pistons arranged oppositely on both sides of the cylinder with the compression space in between. and (1) a drive mechanism for synchronously reciprocating each piston by setting a phase difference of 180 degrees between the two pistons. With this configuration, by setting the specifications such as the mass of the movable parts including the pistons to be the same on both piston sides facing each other, the force generated on each piston side during operation is equal in 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, preventing compressor vibration and the noise generated by vibration. will be done.

[Embodiments of the invention]

1 and 2 each show the structure of a different embodiment of the present invention, and the same members as in FIG. 3 are given the same reference numerals. First, in the embodiment shown in FIG. 1, a cylinder 2 having a compression space 2a for the working medium is installed in the case 1.
A pair of pistons 2A and 2B are disposed facing each other on both the left and right sides of the cylinder. Note that the pistons 2^ and 2B 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 installed here as in FIG. 3. On the other hand, the pistons 2A and 2B described above are attached 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 wrapped around a non-magnetic sleeve 13 installed on the piston shaft 12 of each piston 3A and 3B, and a cylinder positioned opposite to the inner and outer circumferences of the solenoid coils. Interposed between the yokes 15 and 16 (however, in the illustrated embodiment, the cylinder 2 made of magnetic material also serves as the inner yoke 15) and the yokes is and te, which constitute a magnetic path of The magnet device is composed of a cylindrical permanent magnet 17 and a magnet device. Note that this permanent magnet 17 has its inner and outer peripheral surfaces magnetized to N and S poles. Further, the above-mentioned solenoid coils 14^ and 14B have opposite coil winding directions, and are connected to an AC power source (not shown) via a lead wire connection terminal 18. Further, springs 19 are interposed between the pistons 3A, 3B, the case 1, and the left and right end plates, respectively, for returning each piston 3A, 3B to a neutral position when the compressor is not in operation. Next, the operation of the compressor with the above configuration will be explained. First, on the magnet device side described above, a directional magnetic field is formed in the space between the yokes 15 and 16 in the middle of the closed loop magnetic path from the N pole of the permanent magnet 17 to the S pole of the magnet via the yokes 15 and 16. has been done. Here, solenoid coil 14A
, 14B, an axial electromagnetic force acts due to the interaction with the unidirectional magnetic field generated by the magnet device described above according to Fleming's left hand rule, and this electromagnetic force causes the pistons 3A and 3B to move into the cylinder. Driven within 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 described above is alternately reversed in accordance with the power frequency.
The piston will reciprocate alternately left and right. Furthermore, as described above, the winding directions of the solenoid coils 14A and 14B are opposite to each other, so that the pistons 38 and 3B stroke in opposite directions with a phase difference of 180 degrees. In addition, solenoid coil 148,
Instead of reversing the winding direction of the coil 14B, it is possible to similarly set a phase difference of 180 degrees between the stroke operations of the pistons 3A and 3B by reversing the direction of the coil current. Here, piston 3A is on the left, piston 3B
When moves to the right, the volume of the compression space 2a in the cylinder 2 sandwiched between the left and right pistons increases, so the pressure in this space decreases, and the working medium flows into the cylinder through the suction valve 7. When the movement of the piston is reversed during the stroke, and the piston 3A begins to move to the right and the piston 3B to the left, the volume of the compression space in the cylinder decreases, the pressure in the space increases, and the working medium is pressurized and compressed. Discharge valve 8
It will be discharged outward through. Moreover, as is clear from the above explanation of the operation, the pistons 3A and 3B stroke with a phase difference of 180 degrees, and the driving force applied to each piston is the same.
The reaction forces acting on case 1 are also equal in magnitude and 1
Due to the 80 degree phase difference, the directions of the forces are opposite and cancel each other out. Furthermore, this operation is always performed in such a way that they cancel each other out, regardless of whether the power supply frequency of the compressor is variable or when the compressor is started. As a result, it is possible to reliably prevent vibrations of the entire compressor, vibrations propagating outward through the installation foundation of the compressor and the case, and generation of noise. Next, FIG. 2 shows an embodiment in which a reverse Stirling cycle refrigerator is constructed by combining the above compressor with a displacer constructed in a separate expansion cylinder. In FIG. 2, a working medium passage 20 is formed in a case 1 of the compressor as a drawer leading to a compression space in the cylinder body of a cylinder 2, and a cooler 22 is disposed between this passage 20 and an expansion cylinder 21. They are connected by a pipe 23 equipped with. on the other hand,
Inside the expansion cylinder 21, a displacer 26 is housed, which is made up of a hollow free piston 24 with ventilation holes opened on the upper and lower end surfaces and a cool storage body 25 made of a laminate such as a wire mesh built therein. A cold station 27, which serves as an expansion space for the working medium, is formed between the top and the end surface of the expansion piston 25. Reference numeral 28 denotes a spring that constitutes a mass-spring system together with the expansion piston 24 including the cool storage body 25. By appropriately selecting the natural vibration frequency of this mass-spring system, the working fluid in the system generated by compressor operation can be adjusted. In conjunction with the pressure pulsations, the expansion piston 24 reciprocates up and down in the direction of the arrow within the expansion cylinder 21 synchronously with a predetermined phase difference with the movement of the piston. By operating the compressor by combining the compressor and the displacer as described above, as is well known, a working medium (helium A reverse Stirling cycle in which the refrigerant gas (gas, etc.) undergoes an isothermal change in volume and temperature progresses, and the working medium is adiabatically expanded at the cold station 27 on the expansion cylinder 21 side to generate refrigeration. The compressor shown in the embodiment of FIG. 2 is structurally similar to the suction compressor shown in FIG. The discharge valve is omitted and the suction and discharge ports are integrated or one of them is sealed, and the other structure is the same as that shown in FIG. Therefore, the generation of vibration and noise during the operation of the compressor can be effectively prevented, and in combination with the free piston type displacer 26 that utilizes the spring resonance force of the spring 28, there is almost no generation of vibration or noise as a whole of the equipment. It is possible to obtain a vibration-free and noise-free refrigerator. In the above-described embodiment, a solenoid-driven linear motor is used as the piston drive mechanism, but the present invention is not limited to this method, and a mechanical drive mechanism may also be used.

【Effect of the invention】

As described above, according to the present invention, there is provided a cylinder with both ends open in which a compression space for a working medium is formed in the cylinder, and a pair of pistons disposed oppositely on both sides of the cylinder with the compression space in between. and a drive mechanism for synchronously reciprocating each piston by setting a phase difference of 180 degrees between the two pistons, so that the two pistons face each other across the compression space in the cylinder. The vibrations generated by the reciprocating motion of the pair of pistons are always canceled out between the pistons, regardless of fluctuations in the drive frequency, resulting in zero vibration in the compressor. Noise reduction can be achieved.

[Brief explanation of the drawing]

FIGS. 1 and 2 are cross-sectional views of different embodiments of a reciprocating compressor according to the present invention, and FIG. 3 is a cross-sectional view of a conventional reciprocating compressor. Compressor case, 2 cylinders, 2a: compression space, 3
A, 3B, Piston, 4A, 4B: Piston drive mechanism, 7: Suction valve, 8: Discharge valve, 12: Piston shaft, 14A
, 148: Solenoid coil, 15.16: Yoke forming a magnetic path, 17: Permanent magnet, 21: Expansion cylinder,
26: Displacer.

Claims (1)

[Scope of Claims] 1) a cylinder with both ends open forming a compression space for a working medium in the cylinder; a pair of pistons disposed opposite to each other on both sides of the cylinder with the compression space in between; A reciprocating compressor characterized by comprising a drive mechanism that sets a phase difference of 180 degrees between both pistons and reciprocates each piston synchronously. 2) In the compressor according to claim 1, the drive mechanism includes a solenoid coil connected and supported to the piston shaft of each piston, and magnets arranged opposite to each other on the inner and outer circumferential sides of the solenoid coil with the solenoid coil in between. It consists of a fixed-side magnet device consisting of an inner and outer double cylindrical yoke that forms a path and a permanent magnet interposed between the yokes, and the alternating current supplied to the solenoid coil and the magnet device side A reciprocating compressor characterized by being a solenoid-driven linear motor that reciprocates a piston within a cylinder using electromagnetic force generated by interaction with a generated directional magnetic field. 3) In the compressor described in claim 2, the solenoid-driven linear motors attached to each piston are configured such that the coil winding direction or current direction of the solenoid coils is set to be opposite to each other so that the same AC power source is used. A reciprocating compressor characterized by synchronous operation. 4) A reciprocating compressor according to claim 2, wherein the cylinder itself also serves as an inner cylindrical yoke. 5) A reciprocating type compressor according to claim 1, characterized in that a suction valve and a discharge valve for the working medium are installed at the suction port and the discharge port, respectively, which communicate with the central portion of the cylinder body of the cylinder. Compressor 6) In the compressor according to claim 1, the compression space in the cylinder of the compressor communicates between the piston movement of the compressor and a displacer that reciprocates within the expansion cylinder with a predetermined phase difference. A reciprocating compressor characterized in that the reciprocating compressor is connected with piping, and these constitute a reverse Stirling cycle refrigerator.