JPH0670533B2 - refrigerator - Google Patents

Description

TECHNICAL FIELD The present invention relates to, for example, a separated Stirling refrigerator that cools an infrared detection element to an extremely low temperature.

[Conventional technology]

FIG. 5 shows a configuration example of a conventional Stirling refrigerator. In the figure, the refrigerator is roughly divided into a compressor 1 , an expander 2, and a connecting pipe 3.

The compressor 1 includes a cylindrical cylinder 4, a cylinder head 5 that seals one end face of both open end faces of the cylinder 4, a piston 6 that reciprocates in the cylinder 4, a cylinder 4, a cylinder head 5, and a piston 6. A mechanism which is composed of a compression chamber 7 which is a space separated by a space, and a connecting rod, a crank, a crankshaft, a crankcase, etc., which are drive mechanism parts (not shown) of the piston 6, and which drives the piston 6 by an electric motor via the drive mechanism. It has become.

The expander 2 is provided with a cylindrical expansion cylinder 10 in which one of both open end faces is an end plate 8 and the other end is sealed with a casing 9. There is a displacer 13 supported on the casing 9 via a coil spring 11 at the midpoint of the stroke of the reciprocating motion, which reciprocates in the expansion cylinder 10 like a piston.
The coil spring 11 and the displacer 13 form a vibration system. The cool storage chamber 16 partitioned and formed inside the displacer 13 is filled with a cool storage material 14 made of fine mesh, laminated wire mesh, lead, or resin, etc., so that the refrigerant gas does not leak from the gap between the expansion cylinder 10 and the displacer 13. As described above, the seal material 12 made of resin or the like is fitted around the displacer 13. The space defined by the displacer 13, the expansion cylinder 10 and the end plate 8 and the space defined by the displacer 13, the expansion cylinder 10 and the casing 9 form an expansion chamber 17 and a high temperature chamber 15, respectively. The chamber 15, the cold storage chamber 16, and the expansion chamber 17 are provided with a refrigerant gas flow path that communicates with each other.

The connection pipe 3 forms a refrigerant gas flow path connecting the compression chamber 7 and the high temperature chamber 15.

The conventional refrigerator configured as described above includes the compression chamber 7, the high temperature chamber, and the high temperature chamber.
Refrigerant gas flow passages that mutually connect 15, the cold storage chamber 16, the expansion chamber 17, and each chamber form an operating space, and in this operating space, for example, high pressure refrigerant gas such as helium and hydrogen is sealed. There is.

The operation of the conventional Stirling refrigerator as described above will be described below. The high-temperature high-pressure refrigerant gas compressed in the compression stroke of the piston 6 in the compression chamber 7 flows into the high-temperature chamber 15 of the expander 2 through the connecting pipe 3 and top-displaces the displacer 13 at the midpoint position. It is pushed up against the force of the coil spring 11 to the point position, and enters the expansion chamber 17 at a low temperature via the regenerator chamber 16 formed in the displacer 13. The refrigerant gas that has entered the cold storage chamber 16 is a pressure loss due to the viscous resistance of the refrigerant gas when passing while being cooled in the cold storage chamber 16, so that it gradually flows into the expansion chamber 17 and the refrigerant in the expansion chamber 17 When the gas pressure becomes the same as the refrigerant gas pressure in the high temperature chamber 15, the displacer 13
Returns to the midpoint position. On the other hand, since the piston 6 is in the expansion stroke and the pressure of the refrigerant gas in the compression chamber 7 decreases, the pressure of the refrigerant gas in the high temperature chamber 15 also decreases, and the refrigerant gas in the expansion chamber 17 expands to lower the temperature. Due to the pressure loss when passing the cold storage material 14 in the cold storage chamber 16 while cooling it, a pressure difference is generated between the refrigerant gas pressure in the expansion chamber 17 and the refrigerant gas pressure in the high temperature chamber 15, and this pressure difference. As a result, the displacer 13 is further pushed to the bottom dead center, so that the refrigerant gas in the expansion chamber 17 further expands to a low temperature and absorbs the ambient heat, thereby performing a refrigerating action. The refrigerant gas in the expansion chamber 17 is then stored in the cold storage chamber.
It passes through 16 while cooling the regenerator material 14 in it,
Return to the compression chamber 7 via. That is, in the Stirling refrigerator, the piston 6 of the compressor 1 and the displacer 13 that reciprocates in the expander 2 are interlocked with each other with a certain phase difference so that the refrigerant gas is compressed.
Generates heat and becomes low temperature in the expansion chamber 17. By repeating the above-mentioned heat cycle, the temperature of the cylindrical wall of the expansion cylinder 10 forming the expansion chamber 17 and the end plate 8 can be cooled to about 80K.

[Problems to be Solved by the Invention]

However, in the conventional device as described above, as described above, the piston 6 of the compressor 1 and the displacer 13 that reciprocates like a piston in the expander 2 are interlocked with each other with a certain phase difference. The temporal change of the position draws a sinusoidal waveform, and the fluid viscous resistance when the refrigerant gas passes through the cold storage chamber 16 and the action of the coil spring 11 cause the refrigerant in the high temperature chamber 15 and the expansion chamber 17 to become refrigerant. The gas pressure change causes a phase difference, and the displacer 13 is driven by the refrigerant gas pressure difference between the high temperature chamber 15 and the expansion chamber 17 caused by this phase difference. For this reason, there is a limit in that the phase difference cannot be so large due to the stable condition of the operation of the vibration system, and there is a problem that the total amount of work of the refrigerant gas in the expansion chamber 17 is small.

That is, the total work of the refrigerant gas in the expansion chamber 17
Q _c, the refrigerant gas pressure within the expansion chamber 17 P _c, the volume of the expansion chamber 17
V _c , the position of the displacer 13 is x, the volume expansion of the expansion chamber 17 and the displacement of the displacer 13 when the refrigerant gas pressure in the expansion chamber 17 is P _c are dV _c and dx, respectively.
If the cross-sectional area of the expansion chamber 17 side expansion cylinder 10 of 3 is S,
The total work Q _c of the refrigerant gas in the expansion chamber 17 is represented by the following equation.

Q _c = P _c · dV _c = SP _c · d _x ... where mass of the displacer 13 is m, spring constant of the coil spring 11 is k, and fluid viscosity when refrigerant gas passes through the regenerator 16 It is assumed that the resistance is c, the amplitude value and the angular frequency of the pressure difference of the refrigerant gas between the high temperature chamber 15 and the expansion chamber 17 which are the driving force of the displacer 13 are F ₀ and ω, and the time is t.
The pressure difference of the refrigerant gas between the high greenhouse 15 and the expansion chamber 17 is the cold storage chamber.
It is generated only by the fluid viscosity resistance when the refrigerant gas passes through the inside of 16, and this fluid viscosity resistance value is proportional to the speed of the piston 6. On the other hand, since the position and speed of the piston 6 change with time in a sinusoidal waveform, F ₀ also acts on the displacer 13 as a force having a sinusoidal waveform, so the position x of the displacer 13 is expressed by the following equation.

m + c + kx = F ₀ cos ωt ... Therefore, x changes in a sine waveform with a delay of a certain phase with respect to the sine waveform of the refrigerant gas pressure difference between the high temperature chamber 15 and the expansion chamber 17. Figure 2 shows the refrigerant gas pressure (P
The time change of _c ) is shown in (a), and the time change of the position (x) of the displacer 13 is shown in (b). In the figure, the position (x) of the displacer 13 and the temporal change of the refrigerant gas pressure (P _c ) in the expansion chamber 17 both show a sine waveform, and the phase difference between P _c and x is the fluid in the regenerator chamber 16. It is determined by the viscous resistance and the coil spring 11. However, (e) of FIG. 3 shows the time change of the refrigerant gas pressure (P _c ) in the expansion chamber 17 and the volume (V _c ) of the expansion chamber 17, but the time change of x shows a sinusoidal waveform. Due to the stable condition of the operation of the oscillating system drawn, the phase difference cannot be so large that there is a limit, so the area surrounded by the diagram (e) and equivalent to the total work of the refrigerant gas in the expansion chamber 17 Of the refrigerant gas in the expansion chamber 17 is small.

It is an object of the present invention to provide a refrigerator having a high refrigerating capacity by making the temporal change of the position of the displacer deviate from a sinusoidal waveform and increasing the total amount of work of the refrigerant gas in the expansion chamber.

[Means for Solving the Problems]

In order to achieve the above object, a refrigerator according to the present invention includes a cylindrical cylinder, a cylinder head that seals one end face of both opening end faces of the cylinder, a piston that reciprocates in the cylinder, and A compressor having a cylinder, a compression chamber partitioned by the cylinder head and the piston, a tubular expansion cylinder in which one of both opening end surfaces is closed by an end plate and the other end by a casing, and the inside of the expansion cylinder A displacer that reciprocates like a piston and is supported on the inner surface of the casing via a coil spring at the midpoint of the stroke of the reciprocating motion, and a cool storage chamber that is compartmentally formed inside the displacer and is filled with a cool storage material. An expansion chamber partitioned by the displacer, the expansion cylinder, and the end plate, the displacer, the expansion cylinder, and the case. In a refrigerator in which a refrigerant gas flow path is in communication with the compression chamber, the high temperature chamber, the cold storage chamber, and the expansion chamber, a pair of magnets having magnetic poles The magnets are arranged in the high temperature chamber so as to face each other and the magnetic field lines of the magnetic poles coincide with the cylindrical axis of the expansion cylinder, and one of the pair of magnets is fixed to the displacer end face and the other is fixed to the casing.

[Action]

In the present invention, a pair of magnets are arranged in the high temperature chamber of the expander with their magnetic poles facing each other and the magnetic lines of force of these poles aligned with the cylindrical axis of the expansion cylinder. Since it is fixed to the other casing, the restoring force of the coil spring from the bottom dead center to the middle point of the displacer's reciprocating stroke or the restoring force of the coil spring from the top dead center to the middle point is reduced by the action of the magnet. As a result, the temporal change of the position of the displacer can be deviated from the sine waveform, and the total amount of work of the refrigerant gas in the expansion chamber can be increased.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. The same or similar parts as in FIG. 5 are designated by the same reference numerals. Since the compressor part is the same as that of FIG. 5, its illustration and description are omitted.

The expander 2 is provided with a cylindrical expansion cylinder 10 in which one of both open end faces is closed by an end plate 8 and the other end is closed by a casing 9. There is a displacer 13 supported on the casing 9 via a coil spring 11 at the midpoint of the stroke of the reciprocating motion, which reciprocates in the expansion cylinder 10 like a piston.
The coil spring 11 and the displacer 13 form a vibration system. A cool storage chamber 16 is defined inside the displacer 13, and the cool storage chamber 16 is filled with a cool storage material 14 made of fine mesh, laminated wire mesh, lead or resin. Further, a sealing material 12 made of resin or the like is fitted around the displacer 13 so that the refrigerant gas does not leak from the gap between the expansion cylinder 10 and the displacer 13. The space defined by the displacer 13, the expansion cylinder 10 and the end plate 8 and the space defined by the displacer 13, the expansion cylinder 10 and the casing 9 are the expansion chamber 17 and the high temperature chamber, respectively.
Forming 15 and. Further, the magnets 19 and 20 are arranged in the high temperature chamber 15 so that the magnetic lines of their magnetic poles coincide with the cylindrical axis of the expansion cylinder 10 and the different magnetic poles face each other. And the other is fixed to the casing. In addition, the cool storage room 16,
The expansion chamber 17 and the high temperature chamber 15 are provided with a refrigerant gas flow path that communicates with each other.

The connection pipe 3 forms a refrigerant gas flow path connecting the compression chamber 7 and the high temperature chamber 15.

In the above configuration, the influence of the attraction force of the magnets 19 and 20 on the vibration system formed by the displacer 13 and the coil spring 11 is that the displacer 13 moves from the top dead center to the bottom dead center when reciprocating in the expansion cylinder 10. It acts as an accelerating force when heading toward, and acts as a decelerating force when heading toward bottom dead center or top dead center. However, the displacer 13 has a coil spring 11
Since the force also acts, the total restoring force that is the restoring force that combines the forces of the coil spring 11 and the magnets 19 and 20, that is, the restoring force that returns the displacer 13 to the midpoint of the stroke of its reciprocating motion is shown in FIG. The curve is as shown in. In the figure, the force exerted on the displacer 13 by the magnets 19 and 20 and the coil spring 11 is the restoring force. The restoring force is 0 at the origin, the force acting in the bottom dead center direction is +, and the force acting in the top dead center direction is +. The vertical axis with the working force as − and the middle point of the reciprocating motion of the displacer 13 as the origin (0)
The side is the top dead center direction and the-side is the bottom dead center direction, and the horizontal axis is the coordinate axis. Since the restoring force of the coil spring 11 is proportional to the position x of the displacer 13, it becomes a straight line (g). Also, since the restoring force of the magnets 19 and 20 is inversely proportional to the distance between the magnets 19 and 20, the curve (f)
Becomes On the other hand, the position x of the displacer 13 is the position of the displacer 13, the mass of the displacer 13 is m, the spring constant of the coil spring 11 is k1, the magnetic attraction force constant of the magnets 19 and 20 is k.
2, c is the fluid viscosity resistance when the refrigerant gas passes through the cold storage chamber 16, and the magnet 1 when the displacer 13 is at the midpoint position.
The distance between 9 and 20 is d, the amplitude and angular frequency of the pressure difference of the refrigerant gas pressure between the expansion chamber 17 and the high temperature chamber 15, which are the driving force of the displacer 13, are F ₀ ,, ω, respectively, and the time is The position x of the displacer 13 is represented by the following equation.

m + c + k1 _x + k ₂ / (x + d) ² = F ₀ cosωt
Therefore, the change of the position x of the displacer 13 is as follows. First, since the total restoring force when the displacer 13 goes from the midpoint to the top dead center or when the displacer 13 returns from the top dead center to the midpoint is somewhat larger than that of the coil spring 11 alone, the displacer 13 uses only the conventional coil spring 11. In case of, reach top dead center or return to midpoint sooner. Next, since the total restoring force when the displacer 13 moves from the midpoint to the bottom dead center or when the displacer 13 returns from the bottom dead center to the middle point is much smaller than that of the conventional coil spring 11, the displacer 13 uses the coil spring 11. It reaches the bottom dead center or returns to the midpoint more slowly than in the case of only. In this case, the movement of the displacer 13 is restricted by the magnets 19 and 20 at the bottom dead center position depending on the mounting intervals of the magnets 19 and 20, and the displacer 13 only descends to the point where the magnets 19 and 20 contact. The change in the position x of the displacer 13 with time is shown by the curve (c) in FIG. As is clear from the figure, the curve (c) is below the curve (b) in the case of only the conventional coil spring 11 shown by the broken line, the upper side of the wave is sharp and the lower side of the wave is It has a swollen shape and is a curve that deviates from the sine waveform. In this case, the total amount of work of the refrigerant gas in the expansion chamber 17, the change of the refrigerant gas pressure in the expansion chamber 17 and the high temperature chamber 15 is hardly affected by the position of the displacer 13,
The area surrounded by the curve (d) showing the temporal change of the refrigerant gas pressure (P _c ) in the expansion chamber 17 and the volume (V _c ) of the expansion chamber 17 in FIG. The curve (e) is the refrigerant gas pressure (P _c ) in the expansion chamber 17 and the volume (V
_The curve (d) clearly shows the displacer using magnets 19 and 20.
It is shown that when the time change of the position x of 13 is a curve deviated from the sine waveform, the total amount of work of the refrigerant gas in the expansion chamber 17 becomes large, and the refrigerator has a high refrigerating capacity. There is. When the opposite magnetic poles of the magnets 19 and 20 have the same polarity, the curve of the time change of the position x of the displacer 13 is opposite to the opposite polarity, and the upper wave swells,
The wave on the lower side becomes a sharp curve, and the total amount of work of the refrigerant gas in the expansion chamber 17 increases, so that the same effect as in the case of the different polarity can be obtained.

〔The invention's effect〕

In the refrigerator according to the present invention, a pair of magnets are arranged in the high temperature chamber such that their magnetic poles face each other and the magnetic field lines of the magnetic poles and the cylindrical axis of the expansion cylinder coincide with each other. Since the other end of the displacer is fixed to the casing, the restoring force of the coil spring from the bottom dead center to the middle point of the displacer's reciprocating stroke or the restoring force of the coil spring from the top dead center to the middle point is reduced by the action of the magnet. By doing so, it is possible to increase the total amount of work of the refrigerant gas in the expansion chamber and to increase the refrigerating capacity of the refrigerator.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing the essential configuration of an embodiment of the refrigerator of the present invention, and FIG. 2 is a graph showing changes over time in the refrigerant gas pressure (P _c ) in the expansion chamber of the refrigerator of the present invention and the conventional refrigerator. FIG. 3 is a diagram showing the time variation of the position x of the displacer, and FIG. 3 shows the time variation of the refrigerant gas pressure (P _c ) in the expansion chamber and the volume (V _c ) of the expansion chamber of the present invention and the conventional refrigerator. FIG. 4 is a diagram showing the respective restoring forces of the coil spring and the magnet acting on the displacer, and the curves of the total restoring force obtained by combining these, and FIG. 5 is a sectional view showing the configuration of a conventional refrigerator. is there. 1 ... Compressor, 2 ... Expander, 3 ... Connection pipe, 4 ... Cylinder,
5 ... Cylinder head, 6 ... Piston, 7 ... Compression chamber, 8 ...
End plate, 9 ... Casing, 10 ... Expansion cylinder, 11 ... Coil spring, 12 ... Seal material, 13 ... Displacer, 14 ... Cool storage material, 15 ... High temperature chamber, 16 ... Cool storage chamber, 17 ... Expansion chamber, 19, 20 ... magnet.

Claims (1)

[Claims] 1. A cylindrical cylinder, a cylinder head for sealing one end face of both open end faces of the cylinder, a piston reciprocating in the cylinder, and a cylinder, the cylinder head and the piston for partitioning. A compressor having a compression chamber, a cylindrical expansion cylinder in which one end of both opening end faces is closed by an end plate and the other end is closed by a casing, and the inside of this expansion cylinder reciprocates like a piston. The displacer supported on the inner surface of the casing via a coil spring at the midpoint of the stroke of the step, the regenerator chamber formed inside the displacer and filled with the regenerator material, the displacer, the expansion cylinder, and the end plate. An expander including a partitioned expansion chamber and a high temperature chamber partitioned by the displacer, the expansion cylinder, and the casing. In the refrigerator in which the refrigerant gas flow path communicates with the compression chamber, the high temperature chamber, the cold storage chamber, and the expansion chamber, a pair of magnets are made to face their magnetic poles, and the magnetic force lines of the magnetic poles and the cylindrical shaft of the expansion cylinder are Are arranged in the high temperature chamber so that the two coincide with each other, and one of the pair of magnets is fixed to the end face of the displacer and the other is fixed to the casing.