JPH08285396A - Piston driving mechanism for gas compressor - Google Patents

Abstract

PURPOSE: To reduce a variation of load torque, vibration and noise generated when a power source is rotationally driven by a method wherein a maximum value of a load of the power source for sliding a piston is lowered. CONSTITUTION: A piston rod 22 of a piston 21 is provided with a driving auxiliary member made of magnetic material or permanent magnet. There is provided a first electromagnetic coil 51 at a position where the driving auxiliary member approaches when the piston 21 reaches its top dead center. There is also provided a second electromagnetic coil 52 at a position where the driving auxiliary member reaches when the piston 21 reaches a lower dead center. Each of the electromagnetic coils is connected to switches 53a to 53d. The switches 53a to 53d are operated such that the first electromagnetic coil 51 is electrically energized during an operation in which the piston 21 reaches near its top dead center, the electrical energization for the first electromagnetic coil 51 is terminated when the piston 21 reaches its lower dead center and further the electrical energization of the second electromagnetic coil 52 is terminated when the piston 21 reaches its lower dead center.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas compressor for a Stirling refrigerator or the like which produces refrigeration by sliding a piston and / or a displacer, and in particular, a piston drive of the gas compressor for smoothly sliding the piston. It is related to the mechanism.

[0002]

2. Description of the Related Art Conventionally, helium filled in a closed space,
2. Description of the Related Art There is known a device that compresses and expands a refrigerant gas such as nitrogen to generate freezing. Examples of the device include a Stirling refrigerator. The refrigerator is capable of generating ultra-low temperature, and is being used for various infrared sensors, cooling of superconducting devices, freezer for biomedical, and the like. The gas compressor is applied to the refrigerator and compresses and expands the refrigerant gas.

FIG. 19 shows a one-piston, one-displacer type Stirling refrigerator (1), in which the displacer (31) and the piston (21) are rotated by the rotation of the crankshaft (61).
, But they slide with a phase difference of 90 °. Refrigerant gas such as helium gas filled in the casing (11) is compressed and expanded in the compression chamber (24) by sliding the piston (21), and displacer chamber (3) is moved by sliding the displacer (31). Of the expansion chamber (34) and the displacer-side lower space (35) are connected to each other through the gas flow passage (14) and the regenerative heat exchanger (15) arranged in the gas flow passage (14), Ultra-low temperature freezing is generated in (34) and high temperature is generated in the compression chamber (24). The ultra-low temperature freezing generated in the expansion chamber (34) cools the sensor and the like.

[0004]

In a refrigerator in which a piston (21) is slid by a crank mechanism to compress and expand refrigerant gas, the phase of the piston (21) and the power source for driving the crank mechanism are used. The required torque draws a waveform as shown by the broken lines in FIGS. 8 and 7, respectively. Displacer (31)
Since the expansion chamber (34) and the lower space (35) on the displacer side are communicated by the gas flow passage (14), the refrigerant gas pressure in both chambers is kept the same, and the displacer (31) is It slides regardless of pressure. Stirling refrigerator so that the steady state, that is, the generated refrigeration and high temperature are constant
When (1) is running, the load on the power source depends on the phase of the piston (21).

When selecting the power source of the refrigerator, the maximum value of the load torque applied to the power source is important. That is,
If the maximum value of the load torque is large, it is necessary to select a power source having a driving force that matches the maximum value, and the power source becomes large. Further, when the difference between the maximum value and the minimum value of the load torque is large, vibration and noise are generated when the power source is rotationally driven.

The inventor reduces the maximum value of the load applied to the power source to reduce the difference between the maximum value and the minimum value of the load torque, and to reduce the maximum value of the driving force required for the power source. It is considered that the vibration source can reduce vibration and noise generated when the power source is rotationally driven, and can reduce the size of the power source.

The object of the present invention is to reduce the fluctuation of the load torque by lowering the maximum value of the load of the power source linked to the crank mechanism for sliding the piston, and to generate when the power source is rotationally driven. Vibration and noise.

[0008]

In order to solve the above problems, in the piston drive mechanism of the gas compressor of the present invention, the piston rod (22) of the piston (21) has a magnetic material or a permanent magnet. Drive assisting body (5) formed by, when the piston (21) reaches the top dead center
The first electromagnetic coil (51) is provided at a position where (5) approaches, and the second electromagnetic coil (52) is provided at a position where the drive assisting body (5) approaches when the piston (21) reaches the bottom dead center. A switch (53) is connected to each electromagnetic coil. The switch (53) is a piston
The first electromagnetic coil (51) is energized while (21) is moving toward the top dead center, and when the piston (21) reaches the top dead center, the energization to the first electromagnetic coil (51) is stopped and the piston ( 21) energizes the second electromagnetic coil (52) while moving toward the bottom dead center, and the piston (2
When 1) reaches the bottom dead center, the power supply to the second electromagnetic coil (52) is stopped. The drive assist body (5) is reciprocated by energization.

When the drive assisting body (5) is made of a magnetic material, the power source communicating with the first and second electromagnetic coils (51) and (52) may be alternating current or direct current. In addition, drive assist body (5)
When is formed by a permanent magnet, the power supply to the first electromagnetic coil (51) and the second electromagnetic coil (52) is DC.

[0010]

In the process in which the piston (21) moves toward the top dead center by the rotation of the crank mechanism connected to the power source (4), the switch (53) causes the first electromagnetic coil to move.
Energize (51). By energizing, the first electromagnetic coil
Magnetic flux is generated in (51), and the drive assisting body (5) is attracted toward the top dead center. When the piston (21) reaches the top dead center, the switch (53) stops the power supply to the first electromagnetic coil (51).

When the crank mechanism rotates further, the piston (21) moves in the direction of approaching the bottom dead center, and the switch (53) causes the second electromagnetic coil (52) to move.
When the current is energized, a magnetic flux is generated in the second electromagnetic coil (52), and the drive assisting body (5) is attracted toward the bottom dead center. When the piston (21) reaches the bottom dead center, the switch (53) stops the supply of power to the second electromagnetic coil (52), and the drive assist body
The suction force to (5) disappears.

When the first or second electromagnetic coil (52) is energized, the electromagnetic coil attracts the drive assisting body (5), so that the power source (4) moves the piston (21) to the top dead center via the crank mechanism. Alternatively, the load to move toward the bottom dead center becomes smaller. piston
After (21) reaches the top dead center or the bottom dead center, in the initial stage of starting to move toward the midpoint, the volume of the refrigerant gas is decreased or increased in the direction of returning to the filled pressure. As a result, since the work is performed in the direction of reducing the torque of the power source (4), a negative load acts on the power source (4). Therefore, in the initial stage of expansion and / or compression, it is not necessary to assist with the drive assisting body (5), so that the switch
The power supply to the electromagnetic coil is stopped by (53).

[0013]

The maximum value of the load applied to the power source (4) is reduced by the magnetic force acting between the electromagnetic coils (51) and (52) and the drive assisting body (5). A low power source (4) can be used. Also, because the difference between the maximum and minimum load torque of the drive source becomes small, the power source
(4) Rotational unevenness is small, low vibration, low noise and power source
(4) can be driven.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a 1-piston 1-displacer type Stirling refrigerator, and FIG. 6 is a cross-sectional view of the Stirling refrigerator (1) of FIG. 1 taken along line XX and viewed in the direction of the arrow.

The Stirling refrigerator (1) has a crank chamber provided with a crank mechanism inside a closed casing (11).
(6) and a displacer that slides by the crank mechanism
It has a displacer chamber (3) equipped with (31) and a cylinder chamber (2) equipped with a piston (21) that slides by a crank mechanism. The cylinder chamber (2) and displacer chamber (3) are
The crank mechanism is arranged at a 90 ° angle with respect to the crank shaft (61) of the crank mechanism.

Crank chamber (6) and displacer chamber (3)
Also, the cylinder chamber (2) has a partition wall (1
Partitioned by 6), crank chamber (6) to back pressure space (25)
Prevent the refrigerant gas and the lubricating oil (17) from entering the (35). A crank shaft (61) is provided inside the crank chamber (6), and a crank pin (63) connecting between two crank arms (62) of the crank shaft (61) has a piston (21) described later. )
And the connecting rod (23) (3) of the displacer (31)
3) is connected. A power source (4) such as an electric motor or an internal combustion engine is connected to one end of the crankshaft (61), and the crankshaft (61) is rotated by rotationally driving the power source (4). Crankshaft (6
The other end of 1) is rotatably supported by the casing 11.
The bottom surface of the crank chamber (6) is filled with lubricating oil (17), and the lubricating oil (17) is applied to the crank mechanism by an oil splasher (18) arranged on the crankshaft (61). Can be splashed.

The cylinder chamber (2) is partitioned by a piston (21), and the side closer to the crank chamber (6) is a back pressure space (25) and the far side is a compression chamber (24). The piston (21) is connected to the piston rod (22). A drive assisting body (5) described later is attached to the piston rod (22), and the back pressure space (25)
Move back and forth. Piston rod (22) and back pressure space (25)
The length and volume of the drive auxiliary body (5) do not overlap or come into contact with the sliding path of the piston (21) and the oil seal (16) of the back pressure space (25) when the drive assisting body (5) reciprocates. It The details will be described later. The piston rod (22) is connected to a connecting rod (23) through a through hole (19) opened at a substantially central portion of the oil seal (16), and the connecting rod (23) is connected to the crankshaft (23). It is connected to the crank pin (63) of 61). An O-ring (21a) is fitted on the outer peripheral surface of the piston (21), and the compression chamber (24) and the back pressure space (2
There is a seal between 5). The compression chamber (24) is connected to a displacer-side lower space (35) of a displacer chamber (3) described later by a gas flow path (13). First and second electromagnetic coils (51) and (52) described later are provided at both ends of the transition path of the drive assisting body (5) inside the back pressure space (25).

The displacer chamber (3) is partitioned by a sliding displacer (31). One closer to the crank chamber (6) is a lower space (35) on the displacer side, and the farther one is an expansion chamber (3).
4) Displacer (31) is fitted with piston rod (32)
The piston rod (32) is connected to a connecting rod (33) through a through hole (19) opened in the approximate center of the oil seal (16), and the connecting rod (33) Is the connecting rod of the piston (21)
(23) is connected to the connected crank pin (63). Therefore, when the crankshaft (61) rotates counterclockwise toward the plane of FIG. 1, the displacer (31) will move more than the piston (21).
It slides in the phase advanced by 90 °. An O-ring (31a) is fitted on the outer peripheral surface of the displacer (31), and the expansion chamber (34)
And a space (35) below the displacer side is sealed. The compression chamber (24) of the cylinder chamber (2) and the displacer chamber
The lower space (35) on the displacer side (3) is connected by the gas flow path (13). Space below the displacer
(35) and the expansion chamber (34) are connected via a gas flow passage (14), in the gas flow passage (14), a regenerative heat exchanger (15) in which metal mesh is laminated is provided. Has been done.

The drive assisting body (5) and the electromagnetic coils (51) (52) will be described in detail below. The drive assist body (5) is a carbon steel plate,
It is formed by processing an iron-based magnetic material having a low magnetic resistance, such as a silicon steel plate, into a disk shape, and is engaged and fixed to the piston rod (22). Since the drive assisting body (5) is integrally attached to the piston rod (22), it reciprocates for the same stroke length as the piston (21). The surface of the drive assisting body (5) near the piston (21) is the upper surface and the other is the lower surface. In addition, the piston (2
When the 1) and the driving auxiliary body (5) reciprocate, the crank chamber
The position farthest from (6) is the top dead center, and the position closest to it is the bottom dead center.

In this embodiment, the first and second electromagnetic coils (5
An example in which three (1) and (52) are arranged around the piston rod (22) will be described. Power supply (54)
However, the number and shape of the electromagnetic coils are not limited to this.

The electromagnetic coils are three first electromagnetic coils, respectively.
(51) and three second electromagnetic coils (52). As shown in FIG. 5, each coil (51) (52) is connected to the DC power supply (54) via the switch (53). . The arrangement will be described later. Each of the electromagnetic coils (51) (52) is formed by winding a copper wire around the iron cores (51a) (52a). By switching the switch (53), the first
It is possible to select any one of a state in which only the electromagnetic coil (51) is energized, only the second electromagnetic coil (52) is energized, and no electromagnetic coil (51) (52) is energized. When energizing each electromagnetic coil (51) (52), a direct current flows through each coil, magnetic flux is generated from the iron cores (51a) (52a), and when the energization is stopped, the iron cores (51a) (52a ) Stops the generation of magnetic flux. The switch (53) is switched at a timing described later in synchronization with the rotation angle of the crankshaft (61).

The first electromagnetic coil (51) is arranged at a position facing the upper surface of the drive assisting body (5) when the drive assisting body (5) reaches the top dead center by moving. The second electromagnetic coil (52)
Is arranged at a position facing the lower surface of the drive assisting body (5) when the drive assisting body (5) moves and reaches the bottom dead center.
The first and second electromagnetic coils (51) and (52) are arranged at intervals of 120 ° about the piston rod (22). Here, the length of the back pressure space (25) and the length of the piston rod (22) will be described. The back pressure space (25) is at least the stroke of the drive assisting body (5) in the moving direction of the drive assisting body (5).
(A in FIG. 1), the thickness of the drive assisting body (5) (B in FIG. 1), and the installation space (C, C ′ in FIG. 1) for the electromagnetic coils (51) and (52) can be secured. have. The length of the piston rod (22) is adjusted so that the piston (21) does not come into contact with the first electromagnetic coil (51) when the piston (21) slides over the same stroke length.

Below, the piston of the Stirling refrigerator (1)
1 to FIG. 4 and FIG. 7 regarding the volume change due to the sliding of the (21) and the displacer (31) and the operation of the drive assisting body (5) of the piston (21), the electromagnetic coil and the switch (53) of the present invention. It will be described with reference to FIG. It should be noted that FIG. 1 shows the case where the piston (21) is at the bottom dead center and the displacer (31) is at the middle point, and will be referred to as “first stage” hereinafter. FIG. 2 shows the case where the piston (21) is at the midpoint and the displacer (31) is at the top dead center, and will be referred to as "second stage" hereinafter. FIG. 3 shows the case where the piston (21) is at the top dead center and the displacer (31) is at the midpoint, and will be referred to as "third stage" hereinafter. FIG. 4 shows the case where the piston (21) is at the midpoint and the displacer (31) is at the bottom dead center, and will be referred to as "fourth stage" hereinafter. Further, FIG. 7 shows a power source (4)
Load torque, Fig. 8 is the phase of the piston (21), Fig. 9 is
It is a graph which shows the applied voltage to an electromagnetic coil, respectively.

By rotating the power source (4),
The crankshaft (61) rotates counterclockwise with respect to the paper surface of FIG. 1, and the first, second, third, and fourth stages are followed to the first stage.
The cycle of returning to the stage is repeated. Stirling refrigerator
The mechanism of (1) generation of ultra-low temperature will be briefly described. The first stage → the second stage is the equal volume stroke, the compression chamber
The refrigerant gas (24) moves through the gas flow path (13) to the displacer-side lower space (35) of the displacer chamber (3).
In the displacer chamber (3), refrigerant gas flows from the expansion chamber (34) into the lower space (35) on the displacer side through the gas flow passage (14) and the regenerative heat exchanger (15). The refrigerant gas in the expansion chamber (34) cooled to an ultralow temperature in the expansion stroke described later,
Cool the regenerative heat exchanger (15).

The second stage → the third stage is a compression stroke.
In the process, the compression chamber (24), the gas passage (13), the displacer-side lower space (35), the gas flow passage (14), the regenerative heat exchanger (15).
Also, the refrigerant gas in the space occupied by the expansion chamber (34) (hereinafter referred to as “surface pressure space”) is compressed. Since the heat of compression due to the compression of the refrigerant gas is released by the heat exchanger (not shown) arranged on the outer periphery of the casing (11) forming the compression chamber (24), the compression stroke is performed isothermally. The third stage to the fourth stage are equal volume strokes, in which the refrigerant gas in the displacer-side lower space (35) flows into the compression chamber (24) through the gas flow path (13). At this time, a part of the refrigerant gas is partially discharged into the lower space (3
It is cooled from 5) through the gas flow passage (14) and the regenerative heat exchanger (15) and moves to the expansion chamber (34).

The fourth step → first step is an expansion stroke in which the refrigerant gas in the surface pressure space is expanded. By expansion,
Although the temperature of the refrigerant gas decreases, this process is carried out isothermally, so that heat is absorbed from a heat exchanger (not shown) arranged on the outer periphery of the casing (11) forming the expansion chamber (34). To do. This absorption of heat corresponds to the cooling capacity.

In the displacer chamber (3), the volumes of the expansion chamber (34) and the displacer-side lower space (35) change at each stage, but the expansion chamber (34) and the displacer-side lower space (35) change. Since the sum of the volumes of (1) and (2) is always constant, it is the volume of the compression chamber (24), that is, the phase of the piston (21) shown in FIG. 8, that influences the pressure fluctuation of the surface pressure space.

First, the switch (53) will be described. The switch (53) has four sensors (53a) (53b) (53c) (53d) mounted on the inner surface of the casing (11) forming the crank chamber (6) as shown in FIGS. 1, 5 and 6. ) And a switching circuit (53e) that operates based on a detection signal from the sensor. The sensor is arranged close to the rotation transition path of the crank arm (62) and detects the crank arm (62) when the piston (21) is located at the bottom dead center (53).
Sensor (53b) every 90 ° counterclockwise with reference to a)
(53c) and (53d) are arranged in order. When each sensor detects the passage of the crank arm (62), it switches the detection signal to the switching circuit (53
Send to e). The state of the switch (53) is the crankshaft (61).
When the rotation angle of is from the first stage to the second stage, that is, when the sensor (53a) emits a detection signal and the sensor (53b) does not emit a detection signal, whichever electromagnetic coil (51) (52) It is located in the state where no electricity is supplied (above). When the second stage to the third stage, that is, when the sensor (53b) emits the detection signal and the sensor (53c) does not emit the detection signal, the contact of the switch (53) is the first electromagnetic coil (51). ) Side (above) and the first electromagnetic coil (51) is energized.
The crankshaft (61) reaches the third stage, the sensor
When (53c) emits a detection signal and the sensor (53d) does not emit a detection signal, the contact of the switch (53) is switched to the state again. Furthermore, when the fourth stage to the second stage,
That is, the sensor (53d) emits a detection signal, and the sensor (53a)
Is not issuing a detection signal, the contact of the switch (53) is switched to the second electromagnetic coil (52) side (above), and the second
Energize the electromagnetic coil (52).

In the process of shifting from the first stage to the second stage and the third stage (section A in FIG. 8), the piston (21) moves from the bottom dead center to the top dead center. The movement of the piston (21) from the bottom dead center to the middle point is caused by the action of the refrigerant gas expanded in the process from the fourth stage to the first stage, which will be described later, to return to the filled pressure, so that the refrigerant gas is transferred to the piston (21 ) To reduce the surface pressure space. Therefore, the load required on the power source (4) is small. However, in the movement from the midpoint to the top dead center, the power source (4) works on the refrigerant gas to compress the refrigerant gas, so that the load required for the power source (4) is the piston (21). ) Becomes larger as it approaches the top dead center. Therefore, the switching circuit (53e) is configured to energize the first electromagnetic coil (51) in the process of the piston (21) shifting from the middle point to the top dead center.
Switch the switch (53) with. First electromagnetic coil (5
When a DC power source is connected to 1) as shown in FIG. 9, a magnetic flux is generated from the coil to attract the drive assisting body (5) toward the top dead center. The torque generated by this suction causes the power source
The torque required for (4) decreases as shown by the solid line in FIG. When the piston (21) reaches the top dead center, the piston (2
1) starts moving toward the bottom dead center, so the first electromagnetic coil
Since it is not necessary to suck the drive assisting body (5) toward the top dead center by (51), the switch (53) is switched by the switching circuit (53e) so as to stop energizing the first electromagnetic coil (51).

In the process of transitioning from the third stage to the fourth stage and the first stage (section B in FIG. 8), the piston (21) moves from the top dead center to the bottom dead center. The movement of the piston (21) from the top dead center to the middle point is such that the refrigerant gas compressed in the process from the second stage to the third stage tries to return to the filled pressure, so that the refrigerant gas is transferred to the piston (21). Perform work to expand the surface pressure space. Therefore, the load required on the power source (4) is small. However, the movement from the midpoint to the bottom dead center causes the power source (4) to work on the refrigerant gas and expand the refrigerant gas. Therefore, the torque required for the power source (4) is ) Becomes larger as it approaches the bottom dead center. Therefore, the switching circuit (53e) is configured to energize the second electromagnetic coil (52) while the piston (21) moves from the middle point to the bottom dead center.
Switch the switch (53) with. Second electromagnetic coil (5
When a DC power source is connected to 2) as shown in FIG. 9, a magnetic flux is generated from the coil to attract the drive assisting body (5) toward the bottom dead center. The torque generated by this suction causes the power source
The torque required for (4) decreases as shown by the solid line in FIG. When the piston (21) reaches bottom dead center, the piston (2
Since 1) starts moving toward the top dead center, the second electromagnetic coil
Since it is not necessary to suck the drive assisting body (5) toward the bottom dead center by (52), the switch (53) switches the switch (53) to stop energizing the second electromagnetic coil (52). Switch.

The timing of starting the energization of the coil by switching the switch (53) is such that the first electromagnetic coil (51) is energized in the process of the piston (21) moving from the bottom dead center to the top dead center. The second electromagnetic coil in the process of moving from the point to the bottom dead center
It is only necessary to energize (52). However, since the magnetic flux generated in the electromagnetic coils (51) (52) is inversely proportional to the square of the distance, if the distance between the drive assisting body (5) and the coil generating the magnetic flux is large, the magnetic flux attracts the magnetic flux. The action is weak. Therefore, it is desirable that the timing of starting energization be after passing through the respective midpoints.

As described above, the drive assisting body (5) and the electromagnetic coil for assisting the movement of the piston (21) are installed in the Stirling refrigerator.
By deploying in (1), the power source as shown in FIG.
Since the maximum load required for (4) becomes small, a power source (4) with a small output can be selected as a drive source for the Stirling refrigerator (1). In addition, the difference between the maximum value and the minimum value is reduced, so that the Stirling refrigerator is
Vibration and noise during driving of (1) are reduced.

In the above embodiment, the DC power source (54) is connected to the electromagnetic coils (51) (52), but an AC power source can be connected instead of the DC power source (54). Further, when a DC power source is connected, the driving auxiliary body (5) can be not only a magnetic material but also a permanent magnet. FIG. 17 shows an example in which a three-phase AC power source (54a) is connected to the electromagnetic coils (51) (52). Similar to the case of connecting to a DC power supply, the switching circuit (53a) (53b) (53c) (53d) and the switching circuit that operates based on the detection signal from the sensor (53
e) and a switch that can be switched by the switching circuit (53e). Each coil of the first electromagnetic coil and the second electromagnetic coil is a three-phase AC power source by switching the switch (53).
It is connected to each phase of (54a) and a three-phase AC voltage as shown in FIG. 18 is supplied. The switching of the switches is the same as in the above-described embodiment, and will be omitted.

FIG. 10 shows another embodiment of the present invention,
A linear motor is used instead of the electromagnetic coils (51) (52). Further, FIG. 11 is an enlarged cross-sectional view of the linear motor portion. The linear motor is composed of a movable body (50a) integrally attached to the piston rod (22) and a stator (50) arranged on the inner circumference of a casing (11) forming a back pressure space (25). To be done. In the following, an example in which the movable body (50a) is provided with the coil (55) and the stator (50) is provided with the permanent magnet (56) will be described, but this arrangement may be reversed. The mechanism of generation of ultra-low temperature in the Stirling refrigerator (1) is the same as above, and will not be described.

The power source (4) of the Stirling refrigerator (1) is
As shown in FIG. 12, it is a motor that rotates with an alternating current, and is connected to an alternating current power source (54) via an inverter (57).

The movable body (50a) is composed of a cylindrical tubular body (58), and the disc (58a) at one end of the tubular body (58) is fixed to the piston rod (22), It is composed of a coil (55) wound along the circumferential surface of (58) and a power feeding means for supplying a current to the coil (55). As shown in FIG. 12, the power feeding means is composed of an inverter (57) and an AC power source (54). The inverter (57) synchronizes the phases of the voltage of the AC power supply supplied to the power source (4) and the voltage of the AC power supply supplied to the coil. 14 and 15 are graphs showing the phase of the voltage of the supplied AC power supply.

The stator (50) is composed of a cylindrical permanent magnet (56) arranged on the inner circumference of the casing (11) facing the transition path of the coil (55). The permanent magnet (56) is arranged so that the inner and outer peripheral surfaces thereof form magnetic poles. In the present embodiment, the inner peripheral surface is arranged so as to have the N pole and the outer peripheral surface is arranged for the S pole. Further, a cylindrical yoke (59) is formed inside the casing (11) so as to be magnetically connected to the inner circumference of the casing (11). The outer periphery of the yoke (59) is the cylindrical body of the movable body (50a).
It is deployed close to the inner circumference of (58), and the inner circumference of the yoke (59) is
The piston rod (22) is arranged so as not to come into contact with it. Through the yoke (59), casing (11) and permanent magnet (56),
A closed magnetic circuit that penetrates the movable body (50a) is formed. The magnetic field is generated in the direction indicated by arrow A in FIG.

An AC power source having the same phase as the power source (4) is connected to a coil (55) of a linear motor composed of the movable body (50a) and the stator (50) via an inverter (57). When a current in the direction of arrow B in FIG. 11 is passed through the coil, the current flowing in the coil (55) receives an electromagnetic force in the direction of arrow B'from the magnetic field.
When the direction of the power supplied to the coil (55) is changed, a current in the direction of arrow C flows through the coil (55) and an electromagnetic force in the direction of arrow C'is received from the permanent magnetic field. The electromagnetic force applied to the coil (55) assists the sliding of the piston (21).

Electromagnetic force generated in the coil (55) and power source (4)
Phase, that is, when an electromagnetic force in the direction of arrow B'is being generated in the coil (55), the piston (21) moves toward top dead center and the coil is moved in the direction of arrow C '. A linear motor is required for the power source (4) by synchronizing the phase of the power source (4) and the linear motor so that the piston (21) moves toward the bottom dead center when force is generated. Torque is reduced.

As shown in FIG. 16, by connecting the coil (55) with an AC power source which is synchronized with the power source (4), as shown in FIG.
Power source (4) to slide piston (21) as shown in
Since the maximum value of the torque required for the above is small as shown in FIG. 16, it is possible to select the power source (4) having a small maximum output value for the Stirling refrigerator (1) as described above.

The above description of the embodiments is for explaining the present invention, and should not be construed as limiting the invention described in the claims or limiting the scope. The configuration of each part of the present invention is not limited to the above-mentioned embodiment, and it goes without saying that various modifications can be made within the technical scope described in the claims.

In the above embodiment, the one piston, one displacer type Stirling refrigerator is explained.
It can also be applied to piston type Stirling refrigerators and the like.

[Brief description of drawings]

FIG. 1 is a sectional view of a Stirling refrigerator having a piston drive mechanism of the present invention.

FIG. 2 is a sectional view of a Stirling refrigerator equipped with the piston drive mechanism of the present invention.

FIG. 3 is a sectional view of a Stirling refrigerator having a piston drive mechanism of the present invention.

FIG. 4 is a cross-sectional view of a Stirling refrigerator having a piston drive mechanism of the present invention.

FIG. 5 is a circuit diagram showing an electric circuit according to an embodiment of the present invention.

6 is a sectional view of the device of FIG. 1 taken along the line XX.

FIG. 7 is a graph showing load torques of power sources of the present invention and a conventional example.

FIG. 8 is a graph showing a phase of a piston.

FIG. 9 is a graph showing applied voltages to a first coil and a second coil.

FIG. 10 is a sectional view showing another embodiment of the present invention.

FIG. 11 is an enlarged sectional view of a linear motor portion.

FIG. 12 is a circuit diagram showing an electric circuit of another embodiment.

FIG. 13 is a graph showing a phase of a piston of another embodiment.

FIG. 14 is a graph showing a voltage applied to a coil.

FIG. 15 is a graph showing a voltage applied to a power source.

FIG. 16 is a graph showing load torque of a power source.

FIG. 17 is a circuit diagram when the power supply of FIG. 5 is a three-phase AC power supply.

FIG. 18 is a graph showing a voltage applied to a three-phase AC power supply.

FIG. 19 is a sectional view of a conventional Stirling refrigerator.

[Explanation of symbols]

 (1) Stirling refrigerator (21) Piston (24) Compression chamber (25) Back pressure space (31) Displacer (34) Expansion chamber (35) Displacer side lower space (4) Power source (5) Drive auxiliary (51) ) 1st electromagnetic coil (52) 2nd electromagnetic coil (55) Coil (56) Permanent magnet (61) Crankshaft

Claims (2)

[Claims] 1. A cylinder chamber (2) in which a piston (21) is slidably fitted in a space sealed with a casing (11) and filled with a refrigerant gas, and the cylinder chamber (2) is partitioned. In a piston drive mechanism of a gas compressor that has a crank chamber (6) in which a crank mechanism is arranged and slides a piston (21) by the crank mechanism, the piston rod (22) of the piston (21) has a magnetic field. A drive assisting body (5) made of a material or a permanent magnet is provided, and when the piston (21) reaches the top dead center, the drive assisting body (5) approaches the first position.
An electromagnetic coil (51) is provided, and a second electromagnetic coil (52) is provided at a position where the drive assisting body (5) approaches when the piston (21) reaches the bottom dead center, and each electromagnetic coil is a switch (53). The switch (53) is connected to the first electromagnetic coil (51) while the piston (21) is moving toward the top dead center, and the piston (2)
When 1) reaches the top dead center, the energization of the first electromagnetic coil (51) is stopped, and the second electromagnetic coil (52) is energized while the piston (21) is moving toward the bottom dead center. ) Reaches the bottom dead center, the energization of the second electromagnetic coil (52) is stopped, and the piston drive mechanism of the gas compressor. 2. A cylinder chamber (2) in which a piston (21) is slidably fitted in a space filled with a refrigerant gas and sealed by a casing (11), and a crank chamber (6) in which a crank mechanism is arranged. In the piston drive mechanism of the gas compressor, which is configured by being divided into and and the piston (21) slides by the crank mechanism, the piston rod (22) of the piston (21)
Alternatively, a coil (55) is provided on one side of the casing (11) and a permanent magnet (56) is provided on the other side, and an AC power source is connected to the power source (4) and the coil (55) of the crank mechanism. Characteristic gas compressor piston drive mechanism.