JP2004116515A - Linear motor drive type compressor and refrigerating machine therewith - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a decrease in refrigerating capacity caused by outgassing, and to miniaturize a linear motor drive type compressor. <P>SOLUTION: Magnetic circuits 56, 80 including a coil 54 is integrated with a airtight container 11 sealing coolant gas, and the coil 54 is arranged in the outside part. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to a linear motor-driven compressor and a refrigerator using the same, and particularly to a regenerative refrigerator used for cooling small measuring elements such as infrared sensors and high-temperature superconducting elements. The present invention relates to a suitable linear motor-driven compressor capable of preventing a decrease in refrigeration capacity due to outgas and capable of being downsized, and a refrigerator using the same.

主 The main use of small regenerative refrigerators is to cool small measuring elements such as infrared sensors. In such applications, reduction of mechanical vibrations during operation of the refrigerator is required.

Therefore, conventionally, as illustrated in FIG. 1, two linear motors (LM) 12, 22 are installed facing each other coaxially with a compressor (also referred to as a compressor) 10, and the pistons 13, 23 are simultaneously moved close to or away from each other. A counter is provided via a spring 30 to a so-called twin-opposed linear motor type, which operates at a phase difference of 180 °, or a single linear motor type using one linear motor 12 as illustrated in FIG. The method of providing the balancer 32 has been adopted.

In the figure, reference numeral 11 denotes a pressure vessel (airtight vessel) for sealing a refrigerant gas, 14, 24 denotes a cylinder in which pistons 13, 23 slide, and 15, 25 denotes pistons 13, 23 in the cylinders 14, 24. Bearings 16 and 26 for slidably supporting the coils 13 and 26 are coils for driving the pistons 13 and 23, and 17 and 27 are bobbins for connecting the coils 16 and 26 and the pistons 13 and 23. , 18 and 28 are yokes, 19 and 29 are permanent magnets fixed to the yokes 18 and 28, and 40 is a refrigerant gas fed from the compressor 10 through a gas passage 38 to cool the low-temperature end 41. This is a cold head (CH) in which a heat exchanger (for example, a wire mesh) 42 is mounted.

However, the driving method used in the conventional linear motor for a compressor, that is, as shown in FIGS. 1 and 2, a moving coil type for driving the coils 16 and 26, or as shown in FIG. In any of the moving magnet types in which the coil 16 is fixed to the yoke 18 and the permanent magnet 19 attached to the bobbin 17 is driven, the thrust generation principle uses Lorentz force, and the driving unit itself is a Lorentz force source. Therefore, the weight and the size of the driving unit are increased, and it is difficult to reduce the vibration during the operation of the compressor to a level required by the market. In addition, since the weight and size of the drive unit are large, there is a limit in reducing the size and weight of the compressor.

In order to solve such a problem, as shown in FIG. 4 (in the case of a piston-driven single linear motor type), the applicant has filed a patent application Ser. It is proposed to drive (not cylinder driven type).

In the drawing, 50 is a mover core connected to the piston 13 (in the case of a piston drive type shown in FIG. 4) or a cylinder (in the case of a cylinder drive type not shown) of the compressor by a bobbin 17, and 52 is a movable core. A permanent magnet 54 disposed near the child core 50, a coil 54, and a magnetic circuit 56 for flowing magnetic flux generated in the coil 54 into the mover core 50 and the permanent magnet 52.

However, the magnetic circuit 56 of such an electromagnet type linear motor is formed by laminating a large number of electromagnetic steel plates 57 in the axial direction of the piston, and an insulating film is attached between the respective electromagnetic steel plates. Therefore, as shown in FIG. 4, when an electromagnet motor is installed inside the hermetic container 11 of the compressor, outgas is generated from the electromagnetic steel plate or the insulating coating of the coil wire, and the outgassing occurs at the tip of the cold head 40 shown in FIG. At the low temperature end 41 (below 200 k or less), it liquefies or solidifies, hinders the movement of the heat exchanger 42, and has a problem that the refrigerating capacity is reduced. In order to reduce the amount of outgas released, the magnetic circuit 56 must be subjected to a treatment such as baking (annealing) for releasing the outgas by heating for a long time in advance. Is the largest component among them, and not only requires large baking equipment (such as an electric furnace), but also costs electricity. Further, the baking time is long, and the time from parts delivery to shipment is also long.

On the other hand, if the baking is insufficient, there is a problem that the refrigerator breaks down due to contamination.

The current supply to the coil 54 installed inside the airtight container 11 needs to be performed by welding a large hermetic connector 60 or a hermetic terminal with high airtightness to the compressor container. Becomes larger. In particular, in high-current driving with a refrigerator driving current of 10 A or more, the pin diameter and the pin interval of the hermetic connector become large, and the influence on the compressor dimensions becomes large. In addition, hermetic terminals and connectors are expensive and have the problem of increasing the cost of the refrigerator.

The present invention has been made to solve the above-mentioned conventional problems, and has as its object to prevent a decrease in refrigeration capacity due to outgas, to enable downsizing, and to prevent a failure of a refrigerator due to contamination.

The present invention provides a linear motor-driven compression system including a coil, a mover connected to a compressor, a permanent magnet disposed close to the mover, and a magnetic circuit for flowing a magnetic flux generated in the coil. This object is achieved by providing a magnetic circuit part including the coil as a part of an airtight container for enclosing a refrigerant gas.

板 In addition, a plate for ensuring airtightness is provided inside the magnetic circuit.

Alternatively, the magnetic circuit has a magnetic block.

The present invention also provides a refrigerator comprising the above-mentioned linear motor driven compressor.

According to the present invention, the amount of outgas from compressor components is reduced, the outgas is liquefied or solidified at the tip of the refrigerator / cold head, hinders the movement of the heat exchanger, and the problem of reduced refrigeration capacity and contamination. Thus, the problem that the refrigerator is broken can be solved. Further, the need for a hermetic connector or terminal is eliminated, and the outer diameter and the overall length of the compressor can be reduced. Furthermore, the coil as a heating element is installed on the atmosphere side, so that the heat radiation efficiency can be improved and the refrigerating capacity can be improved.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

In the first embodiment of the present invention, the present invention is applied to a piston driven single linear motor type compressor similar to the conventional example shown in FIG. 4, and as shown in FIG. A laminated electromagnetic steel sheet 57 or a sintered metal similar to the example is provided, and a metal or non-ferrous metal or non-magnetic plate 70 having a large electric resistance for securing airtightness is disposed inside the laminated electromagnetic steel sheet 57 or sintered metal. The plate 70 is joined to the compressor container 11 by welding or using a sealing member so as to have pressure tightness.

In the figure, reference numeral 72 denotes an elastic support having a peculiarity in the free movement direction, such as two parallel leaf springs, which holds the compressor drive unit (the piston 13 in FIG. 5) and increases the seal life of the compressor. It is long.

The compressor drive unit (piston 13) and the mover core 50 are fastened by bolts or welding using a bobbin 17 made of a member (stainless steel, ceramic, or the like) having a large electric resistance.

間 A completely non-contact clearance seal (gap seal) structure of, for example, 10 μm to 50 μm is provided between the piston 13 and the cylinder 14. Note that a gas bearing seal or a contact seal may be used.

ス ト ロ ー ク It is desirable that the relationship between the stroke of the driving section (piston 13) and the piston diameter is 1: 0.5 to 3.0, the driving frequency is 30 Hz to 70 Hz, and the driving voltage is 230 V or less.

板 The material of the plate 70 is desirably a non-magnetic and weldable material such as stainless steel or aluminum.

The relationship between the gap t between the mover core 50 and the coil 54 and the ratio t / r of the outer radius r of the mover core 50 to the COP defined by the following equation is, for example, as shown in FIG. In order to secure 2%, it is desirable that the ratio t / r is in the range of 6.7 to 11.5% from the viewpoints of manufacturing and performance.

{COP = {Refrigeration capacity (W) / Power consumption (W)} × 100%

Here, the lower limit of 6.7% is a limit at which the plate 70 enters the gap t, and the upper limit of 11.5% is a limit at which the gap t increases and the efficiency decreases.

On the other hand, the relation between the COP and the ratio between the natural frequency ωo and the maximum efficiency operating frequency ωe calculated from the weight of the drive unit and the spring constant of the elastic support member is as shown in FIG. 7, for example, and COP> 2% is ensured. Therefore, it is desirable that the ratio ωe / ωo = 0.77 to 1.02.

In the present embodiment, since the laminated steel plate 57 or the sintered metal of the magnetic circuit 56 does not have a function of retaining the refrigerant gas sealed in the refrigerator, the plate 70 allows the magnetic circuit 56 to withstand pressure and airtightness. Have.

In this embodiment, by adding the plate 70 inside the magnetic circuit 56 similar to the conventional example, the present invention can be realized and the configuration is simplified.

Next, FIG. 8 shows a second embodiment of the present invention applied to a cylinder driven single linear motor type compressor in which the piston 13 is fixed and the cylinder 14 is driven.

In the present embodiment, the piston 13 is fixed, the cylinder 14 is movable, and the cylinder 14 and the mover core 50 are connected by the bobbin 17.

{Circle around (2)} The two elastic supports 72 support both ends of the cylinder 14.

他 The other points including the configuration of the magnetic circuit 56 are the same as those of the first embodiment, and a description thereof will be omitted.

FIG. 9 shows a third embodiment of the present invention applied to a cylinder-driven twin opposed linear motor type compressor.

This embodiment is the same as the second embodiment, except that the same cylinder drive mechanism as the second embodiment is disposed on both sides of the gas flow path 38, and thus the description is omitted.

Next, a fourth embodiment of the present invention will be described with reference to FIG.

In the present embodiment, the present invention is applied to a piston-driven twin-facing linear motor type compressor, and a magnetic circuit 80 has a solid magnetic structure as shown in FIG. 11 (longitudinal sectional view) and FIG. 12 (side view). The magnetic block 82 has a body (for example, iron) block 82 and a slit 83 for preventing eddy current from being generated.

The inner portion of the coil 54 is, for example, welded to a plate 70 made of stainless steel, as in the first embodiment, and the side surface of the permanent magnet 52 is also welded to a plate 71 having a concentric circle shape. On the other hand, since the airtightness is not required for the outer portion of the coil 54, the same laminated steel plate 57 and sintered metal as in the related art can be used, or the same magnetic material with slits as in the other portions can be used.

Next, a fifth embodiment of the present invention will be described in detail with reference to FIG.

In the present embodiment, a magnetic circuit 80 similar to that of the fourth embodiment is used in a twin-opposed linear motor type compressor driven by a cylinder similar to that of the third embodiment.

Other points are the same as those of the third and fourth embodiments, and the description is omitted.

Next, a sixth embodiment of the present invention will be described in detail with reference to FIG.

In this embodiment, the present invention is applied to a cylinder driven single linear motor type compressor 10 to which a cold head (CH) 40 is directly connected.

In the drawing, reference numeral 74 denotes an elastic support for movably supporting the piston 13 together with the heat exchanger 42.

Other points are the same as those in the fifth embodiment, and thus description thereof is omitted.

The present invention relates to a Stirling type refrigerator, a Stirling type pulse tube refrigerator, and a regenerator including a GM (Gifford McMahon) refrigerator by adding a supply / exhaust valve so that high pressure and low pressure can be output. Applicable to general cryogenic refrigerators in general. Also, the combination of piston / cylinder drive, single / twin facing / cold head direct connection is not limited to the embodiment.

The application of the present invention is not limited to the cooling of the infrared sensor and the high-temperature superconducting element, but can be similarly applied to the cooling of the high-temperature superconducting filter, the water trap, the cryopreservation of living cells, and the cooling of the high-temperature superconducting output device.

The present invention is suitable for use in small regenerative refrigerators used for cooling small measuring elements such as infrared sensors and high-temperature superconducting elements.

Schematic diagram showing the configuration of a twin-facing linear motor type compressor driven by a piston Schematic diagram showing the configuration of a piston-driven single linear motor type compressor Schematic showing the main configuration of a moving magnet linear motor Sectional view showing the configuration of a piston driven single linear motor type compressor using an electromagnet type linear motor to explain the problem to be solved Sectional drawing which shows the structure of the single linear motor type compressor of the piston drive which concerns on 1st Embodiment of this invention. Similarly, a diagram showing an example of the relationship between the gap between the mover core and the coil and the outer radius of the mover core, and the COP. Similarly, a diagram showing an example of the relationship between the natural frequency and the ratio of the maximum efficiency operating frequency to the COP. Sectional drawing which shows the structure of the cylinder driven single linear motor type compressor which concerns on 2nd Embodiment of this invention. Sectional view showing the configuration of a cylinder-driven twin opposed linear motor type compressor according to a third embodiment. FIG. 14 is a cross-sectional view showing a main configuration of a piston-driven twin opposed linear motor type compressor according to the fourth embodiment. Longitudinal sectional view showing the configuration of the magnetic circuit used in the fourth embodiment. Same side view Sectional drawing which shows the principal part structure of the cylinder drive twin opposed linear motor type compressor which concerns on 5th Embodiment of this invention. Sectional drawing which shows the structure of the cylinder drive single linear motor type compressor to which the cold head according to the sixth embodiment was directly connected.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 10 ... Compressor 11 ... Airtight container 13 ... Piston 14 ... Cylinder 17 ... Bobbin 38 ... Gas flow path 50 ... Mover core 52 ... Permanent magnet 54 ... Coil 56, 80 ... Magnetic circuit 57 ... Laminated (electromagnetic) steel plate 70, 71 ... plate 82 ... magnetic block 83 ... slit

Claims (4)

Coils and
A mover connected to the compressor;
A permanent magnet disposed in proximity to the mover,
A magnetic circuit for flowing a magnetic flux generated in the coil,
A linear motor driven compressor including
A linear motor-driven compressor, wherein the magnetic circuit portion including the coil is a part of an airtight container for enclosing a refrigerant gas. 4. The linear motor driven compressor according to claim 1, wherein a plate member for ensuring airtightness is provided inside the magnetic circuit. The linear motor driven compressor according to claim 1, wherein the magnetic circuit has a magnetic block. A refrigerator comprising the linear motor-driven compressor according to any one of claims 1 to 3.

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