JPH085178A - Refrigerator - Google Patents

Abstract

PURPOSE:To prevent the damage to inner components due to collision of the components by so connecting an electric input quantity instructing unit for outputting a command to a power source for supplying an AC current to a linear motor as to gradually reduce the current when a refrigerator is stopped. CONSTITUTION:When a refrigerator is stopped, an electric input quantity instructing unit 46 so outputs a command to a power source 4 as to linearly decrease a current to be supplied to a first linear motor 7 and a second linear motor 33. The power source 4 gradually decreases the current to be supplied to the motors 7, 33 based on the command. Thus, when the refrigerator is stopped, the amplitude of the displacer 21 is gradually decreased, and the collision of inner components with one another exceeding the moving range of the displacer 2 can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a Stirling refrigerator for cooling an infrared detecting element to an extremely low temperature of about 80K.

[0002]

2. Description of the Related Art FIG. 7 shows a configuration example of a conventional Stirling refrigerator. The Stirling refrigerator is roughly divided into a compressor 1
A cold finger 2 and a connecting pipe 3 connecting them,
It is composed of a power supply 4. In the compressor 1, the piston 6 positioned by the first support spring 8 has the first cylinder 5
It is structured to reciprocate inside. The piston 6
A light-weight first sleeve 9 made of a non-magnetic material is connected to the first sleeve 9, and a conductor 43 is wound around the first sleeve 9 to form a first movable coil 10. A first lead wire 12 and a second lead wire 13 are connected to the first movable coil 10, and these lead wires 12 and 13 extend to the outside through the wall of the first housing 11 to form a first electrical contact. 14 and the second electrical contact 15 and is connected to the power supply 4. A first annular permanent magnet 16 and a first yoke 17 are provided inside the first housing 11, and these constitute a closed magnetic circuit. The first movable coil 10 has a structure capable of reciprocating in the axial direction of the piston 6 within a gap 18 provided in a closed magnetic circuit composed of the first annular permanent magnet 16 and the first yoke 17. . A permanent magnetic field exists in the gap 18 in the radial direction across the moving direction of the first movable coil 10. The first movable coil 10, the lead wires 12 and 13, the first annular permanent magnet 16, and the first movable coil 10 described above.
The yoke 17 constitutes the first linear motor 7 as a whole. The piston 6 inside the first cylinder 5
The upper internal space is called a compression chamber 19. The compression chamber 19 is filled with a high-pressure working gas such as helium. In order to make it difficult for the working gas in the compression chamber 19 to pass through the gap between the first cylinder 5 and the piston 6,
The gap between the first cylinder 5 and the piston 6 is made as narrow as possible. The above is the configuration of the compressor 1.
On the other hand, the cold finger 2 has a structure in which the displacer 21 positioned by the second support spring 20 reciprocates inside the elongated low temperature cylinder 22. A light second sleep 23 made of a non-magnetic material is connected to a lower portion of the displacer 21, and a conductor 44 is wound around the second sleep 23 to form a second movable coil 24. A third lead wire 26 and a fourth lead wire 27 are connected to the second movable coil 24, and these lead wires 26, 27 are connected to the second housing 2
It is connected to a third electric contact 28 and a fourth electric contact 29 extending to the outside through the wall 5 and is connected to the power source 4. A second annular permanent magnet 30 and a second yoke 31 are provided inside the second housing 25, and these constitute a closed magnetic circuit. The second movable coil 24 has a structure capable of reciprocating in the axial direction of the displacer 21 within a gap 32 provided in a closed magnetic circuit composed of the second annular permanent magnet 30 and the second yoke 31. . A permanent magnetic field exists in the gap 32 in the radial direction across the moving direction of the second movable coil 24. The second movable coil 24 and the lead wire 2 described above
6, 27, the second annular permanent magnet 30, and the second yoke 31 constitute a second linear motor 33 as a whole. The space inside the cold finger 2 is divided into three by the displacer 21, and the space above the displacer 21 is a low temperature chamber 34, the space provided around the center of the displacer 21 is a high temperature chamber 35, and the space below the displacer 21 is below. The space to be covered is called a motor chamber 45. Inside the displacer 21, a regenerator 36 and gas passage holes 37 and 38 are provided, and the low temperature chamber 34 and the high temperature chamber 35 include the regenerator 36 and the gas passage holes 37 and 3.
The regenerator 36 is filled with a regenerator material 39 such as copper wire mesh. A second cylinder 40 is provided around the displacer 21 between the low temperature chamber 34 and the high temperature chamber 35. The second cylinder 40 is provided to prevent the working gas from passing through a gap between the second cylinder 40 and the displacer 21. The gap between the displacer 21 and the second cylinder 40 is made as narrow as possible. Similarly, a third cylinder 41 is provided around the displacer 21 between the high temperature chamber 35 and the motor chamber 45 to make it difficult for the working gas to pass through the gap between the third cylinder 41 and the displacer 21. The gap between the displacer 21 and the third cylinder 41 is made as narrow as possible. Each chamber of the cold finger 2 is filled with a high pressure gas such as helium as in the compressor 1. The above is the configuration of the cold finger 2. The compression chamber 19 of the compressor 1 and the high temperature chamber 35 of the cold finger 2 communicate with each other through the connecting pipe 3. Further, the compression chamber 19, the internal space of the connecting pipe 3, the high temperature chamber 35, the regenerator 36, the low temperature chamber 34, and the gas passage holes 37, 38 are in communication with each other, and the entire chambers are operated. Call it chamber 42. The power source 4 includes the first linear motor 7 and the second linear motor 3
AC current is being supplied to 3.

The operation of the conventional refrigerator configured as described above will be described. In the compressor 1, when an alternating current is supplied from the power source 4 to the conductor 43 of the first movable coil 10 via the electric contacts 14 and 15 and the lead wires 12 and 13, the conductor 43 has a permanent magnetic field in the gap 18. Lorentz force acts in the axial direction by the interaction with. As a result, the piston 6 to which the first movable coil 10 is attached moves vertically in the axial direction. Now, the conductor 4 of the first moving coil 10
When a sinusoidal current is supplied to the piston 3, the piston 6 reciprocates inside the first cylinder 5 to move from the compression chamber 19 to the low temperature chamber 34.
A sinusoidal wave is applied to the gas pressure in the working chamber 42 up to. On the other hand, the gap between the third cylinder 41 of the cold finger 2 and the displacer 21 has a sufficient sealing property for a short cycle pressure change such as a pressure wave generated by the piston 6, but it is sealed when viewed for a long time. Is imperfect, the pressure in the motor chamber 45 is kept around the average pressure of the pressure wave created by the piston 6. The pressure wave created by the piston 6 is the cold chamber 34.
Then, a load obtained by multiplying the pressure difference between the low temperature chamber 34 and the motor chamber 45 by the cross-sectional area of the displacer 21 acts on the displacer 21 in the vertical direction of the displacer 21. Using this force as the gas pressure driving force, the displacer 21 resonates vertically due to the interaction between the gas pressure driving force and the second support spring 20, and the displacer 21 resonates in the vertical direction at the same frequency as the piston 6 and at a phase advanced by about 90 °. Back and forth in the axial direction.
In addition, the cold finger 2 has an electrical contact 2 from the power source 4.
When an alternating current is supplied to the conductor 44 of the second movable coil 24 via the conductors 8 and 29 and the lead wires 26 and 27, the conductor 44 is axially Lorentz-forced by the interaction with the permanent magnetic field in the gap 32. Works. When a sinusoidal current having the same frequency as that of the first moving coil 10 is supplied to the second moving coil 24, the displacer 21 to which the second moving coil 24 is attached reciprocates vertically in the axial direction. This force is the motor driving force. Normally, the gas pressure driving force alone causes the displacer 21 to reciprocate beyond the required amplitude. Therefore, the motor driving force is applied to the displacer 21 so as to be in the opposite phase of the gas pressure driving force, and the necessary and sufficient amplitude is obtained. Is adjusted so that In this way, the motor driving force acts on the reciprocating motion of the displacer 21 in the direction of braking. When the piston 6 and the displacer 21 move as described above, freezing can be generated according to the principle described below.

First, when the displacer 21 is located in the upper portion of the cold finger 2, the piston 6 moves upward to compress the entire working gas in the working chamber 42. The working gas in the compression chamber 19 flows into the high temperature chamber 35 through the connecting pipe 3, and the compression heat generated during the compression is radiated to the ambient air via the first housing 11, the connecting pipe 3, and the like. Next, the displacer 21 moves downward, and the working gas in the high temperature chamber 35 moves to the low temperature chamber 34 through the regenerator 36 and the gas passage holes 37 and 38. At this time, the regenerator material 39 in the regenerator 36 precools the working gas with the cold heat stored before the half cycle. Next, the piston 6 moves downward to expand the entire working gas in the working chamber 42. The working gas also expands in the low greenhouse 34, and this expansion causes low temperature generation in the low temperature chamber 34. Next, the displacer 21 moves upward, and along with it, the low temperature working gas in the low temperature chamber 34 moves to the high temperature chamber 35 through the regenerator 36 and the gas passage holes 37 and 38. At this time, the regenerator material 39 in the regenerator 36 is precooled by the working gas. After that, the piston 6 moves upward again, the compression of the working gas starts, and the same cycle is repeated. Since the compression and expansion of the working gas here are performed while receiving work from the piston 6 and giving work to the piston 6, respectively.
The working gas emits heat when compressed and absorbs heat from the outside when expanded. As described above, when the displacer 21 is located in the upper part of the cold finger 2, that is, when the volume of the low temperature chamber 34 is small, the working gas is compressed. When located in the lower part, that is, in the low temperature chamber 34
Since the expansion of the working gas occurs when the volume of the cold finger 34 is large, the expansion of the low temperature chamber 34 is the whole in one cycle, and the heat is taken from the outside of the tip of the cold finger 2 to cool the cooled object. .

[0005]

The conventional device as described above has the following problems. Second from power
AC current is supplied to the linear motor in the direction to apply braking to the reciprocating motion of the displacer, but if the supply of AC current is suddenly stopped to stop the refrigerator, the motor drive power will disappear instantaneously, but the gas pressure Since the driving force does not disappear instantaneously, the amplitude of the displacer may exceed the amplitude immediately before the stop due to the residual gas pressure driving force. As a result, the displacer exceeds the movable range, and internal parts (for example, the tip of the displacer and the end surface of the low temperature cylinder) may collide and be damaged.

The present invention has been made to solve the above problems, and provides a refrigerator in which the displacer does not exceed the movable range when the refrigerator is stopped and the collision and damage of parts can be prevented. Is intended.

[0007]

In the refrigerator according to the first embodiment of the present invention, the AC current value or the voltage value supplied from the power source to the first linear motor and the second linear motor is the refrigerator. When the electric power is stopped, it is provided with an electric input amount commander which gives an instruction to the power source so that the electric power is gradually decreased so as not to become zero instantaneously.

According to the second embodiment of the present invention, the piston position detector for detecting the position of the piston, the displacer position detector for detecting the position of the displacer, and the position detectors for stopping the refrigerator are output. A position controller for controlling the output current or voltage of the power source is provided so as to gradually reduce the amplitudes of the piston and the displacer when receiving the signals indicating the positions of the piston and the displacer.

[0009]

In the first embodiment of the present invention, the AC current value or the voltage value supplied to the first linear motor and the second linear motor is gradually changed so as not to become zero instantaneously when the refrigerator is stopped. Since the electric input amount commander issues a command to the power source to reduce the amount, it is possible to prevent the displacer from exceeding the movable range and colliding with each other and damaging the internal parts.

Further, in the second embodiment of the present invention, the position controller, which receives the signals indicating the positions of the piston and the displacer output from the piston position detector and the displacer position detector, the piston and the displacer are stopped when the refrigerator is stopped. By controlling the AC current value or voltage value supplied from the power supply to the first linear motor and the second linear motor so as to gradually reduce the amplitude of the Can be prevented from colliding and being damaged.

[0011]

【Example】

Example 1. FIG. 1 is a diagram showing a first embodiment of the present invention.
1 to 45 are the same as those of the above-mentioned conventional device, and the description thereof is omitted here. Reference numeral 46 is an electric input amount commander for instructing the power source 4 so that the AC current value or voltage value supplied to the linear motors 7 and 33 does not instantly become zero but gradually decreases when the refrigerator is stopped. .

Next, the operation of the apparatus of the present invention will be described. The operating principle of the refrigerator shown in this embodiment is exactly the same as that of the conventional apparatus shown in FIG. In this embodiment, when the refrigerator is stopped, the electric input amount commander 4 is operated so as to linearly decrease the currents supplied to the first linear motor 7 and the second linear motor 33 as shown in FIG.
6 issues a command to the power supply 4, and the power supply 4 gradually reduces the current supplied to the first linear motor 7 and the second linear motor 33 based on this command. As a result, when the refrigerator stops, the amplitude of the displacer 21 gradually decreases, and the displacer 21 exceeds the movable range,
It is possible to prevent the internal parts from colliding with each other. Although FIG. 3 shows an example in which the current supplied to the linear motors 7 and 33 is reduced, the present invention can be implemented in the same manner even if the voltage is reduced.

In FIG. 3, the current for stopping the refrigerator is changed linearly, but the same effect can be expected by changing the current in a curved or stepwise manner as shown in FIG.

Example 2. FIG. 2 is a diagram showing a second embodiment of the present invention. 1 to 45 are the same as the above-mentioned conventional device, and the description thereof is omitted here. Reference numeral 48 is a piston position detector that detects the position of the piston, and 49 is a displacer position detector that detects the position of the displacer. 5
When the refrigerator is stopped, 0 detects the amplitudes of the piston 6 and the displacer 21 by the piston position detector 48 and the displacer position detector 49, and receives the detection signal to gradually decrease the amplitude and stop the refrigerator. Is a position controller that controls the current or voltage output from the power supply of.

In the second embodiment shown in FIG. 2, when the refrigerator is stopped, the positions of the piston 6 and the displacer 21 are detected by the piston position detector 48 and the displacer position detector 49, and the piston 6 and the displacer 21 are detected.
Is sent to the position controller 50. The position controller 50 stores the relationship between the time and the amplitude when the refrigerator is stopped as shown in FIG. 5. The stored amplitude is compared with the actual amplitude of the piston 6 and the displacer 21, and the actual piston 6 and the displacer are compared. A command of a current value or a voltage value to be supplied to the first linear motor 7 and the second linear motor 33 is given to the power supply 4 so that the amplitude of 21 approaches this memory. As a result, when the refrigerator is stopped, it is possible to prevent the amplitude of the displacer 21 from exceeding the movable range and causing the internal parts to collide with each other.

Further, in FIG. 5, the amplitude when the refrigerator is stopped is changed linearly, but the same effect can be expected if the amplitude is changed in a curved shape or stepwise shape as shown in FIG.

[0017]

As described above, according to the first embodiment of the present invention, the electric input amount commander can instruct the power supply to gradually decrease the alternating current value or the voltage value when the refrigerator stops. With this configuration, when the refrigerator is stopped, the amplitude of the displacer exceeds the amplitude during operation, and it is possible to prevent the displacer from operating beyond the movable range, which has the effect of preventing damage due to collision of parts.

Further, according to the second embodiment of the present invention, the position controller detects the amplitudes of the piston and the displacer by the piston position detector and the displacer position detector when the refrigerator stops, and gradually detects the detected amplitude. Since it is configured to control the output current or voltage of the power supply so as to stop while reducing it to 1, the amplitude of the displacer exceeds the amplitude during operation when the refrigerator is stopped, and it is possible to operate beyond the movable range. This has the effect of suppressing and preventing damage due to collision of parts.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention.

FIG. 2 is a sectional view showing Embodiment 2 of the present invention.

FIG. 3 is a diagram showing how to control current when the refrigerator is stopped in Embodiment 1 of the present invention.

FIG. 4 is a diagram showing how to control the current when the refrigerator is stopped in the first embodiment of the present invention.

FIG. 5 is a diagram showing how to control the amplitude of the piston and the displacer when the refrigerator is stopped in Embodiment 2 of the present invention.

FIG. 6 is a diagram showing how to control the amplitude of the piston and the displacer when the refrigerator is stopped in Embodiment 2 of the present invention.

FIG. 7 is a cross-sectional view showing a conventional refrigerator.

[Explanation of symbols]

1 compressor, 2 cold fingers, 3 connecting pipes, 4
Power supply, 5 first cylinder, 6 piston, 7 first linear motor, 21 displacer, 22 low temperature cylinder, 33 second linear motor, 34 low greenhouse, 35
High greenhouse, 36 regenerator, 39 cold storage material, 45 motor room,
46 electric input amount commander, 48 piston position detector,
49 Displacer position detector, 50 Position controller.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Michio Otsuka 325 Kamimachiya, Kamakura City Mitsubishi Electric Corporation Kamakura Works (72) Inventor Rieko Yamagishi 214 Kamimachiya Kamakura City Mitsubishi Electric Specialty Machine Systems Co., Ltd. Shonan Business In-house

Claims (2)

[Claims] 1. A first cylinder having a cylindrical inner peripheral surface, and a piston which reciprocates in the first cylinder,
A compressor provided with a first linear motor that reciprocates the piston, an elongated cylindrical low-temperature cylinder, a displacer that reciprocates in the low-temperature cylinder, a distal end of the low-temperature cylinder, and a distal end of the displacer. A low temperature chamber formed between them, a high temperature chamber provided around the central portion of the displacer, a regenerator that stores a regenerator material and connects the low temperature chamber and the high temperature chamber, and a second reciprocating motion of the displacer A cold finger having a motor chamber in which the linear motor is installed, a connecting pipe connecting the compressor and the high temperature chamber of the cold finger, an alternating current to the first linear motor and the second linear motor. A refrigerator provided with a power supply to supply the first linear motor and the second linear motor when stopping the refrigerator. Refrigerator, characterized in that provided an electrical input variable command system for commanding the power supply to gradually reduce supplies alternating current, or a voltage value. 2. A first cylinder having a cylindrical inner peripheral surface, and a piston which reciprocates in the first cylinder.
A compressor provided with a first linear motor that reciprocates the piston, an elongated cylindrical low-temperature cylinder, a displacer that reciprocates in the low-temperature cylinder, a distal end of the low-temperature cylinder, and a distal end of the displacer. A low temperature chamber formed between them, a high temperature chamber provided around the central portion of the displacer, a regenerator that stores a regenerator material and connects the low temperature chamber and the high temperature chamber, and a second reciprocating motion of the displacer A cold finger having a motor chamber in which the linear motor is installed, a connecting pipe connecting the compressor and the high temperature chamber of the cold finger, an alternating current to the first linear motor and the second linear motor. In a refrigerator provided with a power supply to supply, a piston position detector for detecting the position of the piston when stopping the refrigerator, A displacer position detector that detects the position of the displacer, and an output current of the power supply that gradually reduces the amplitudes of the piston and the displacer when receiving signals indicating the positions of the piston and the displacer output from the position detectors. Alternatively, a refrigerator provided with a position controller for controlling voltage.