JPH076701B2 - Gas cycle engine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a gas cycle engine for producing cryogenic temperature.

[Conventional technology]

FIG. 3 is a longitudinal sectional view showing a conventional gas cycle engine disclosed in, for example, Japanese Patent Laid-Open No. 54-28980. In the figure, reference numeral 1 is a cylinder in which a piston 2 and a free displacer 3 reciprocate in mutually different phases. A cooler 5 is housed in the compression space 4 between the working surface of the piston 2 and the working surface 3 a of the displacer 3. Further, the upper working surface 3b of the displacer 3
Defines a boundary of the expansion space 6, which constitutes a working space together with the compression space 4. The heat accumulator 7 provided in the displacer 3 can communicate with the working medium below through the central hole 8 and to the upper working medium through the central hole 9 and the radial flow duct 10. The machine comprises a freezer 11 as a heat exchanger for heat exchange between the expanded cold working medium and the object to be cooled.

Seals 12 and 13 are provided between the piston 2 and the wall of the cylinder 1, and seals 14 and 15 are provided between the displacer 3 and the cylinder.
have. The piston 2 is also provided on its underside with a lightweight sleeve 16 made of a non-magnetic and non-magnetizable material such as hard paper or aluminum. A conductor is wound around the sleeve 16 to form a movable coil 17, which is a lead wire 18 for passing through a wall of a housing 20 hermetically connected to the cylinder 1.
And 19 are connected. These lead wires are connected to electrical contacts 21 and 22 provided outside the housing. The movable coil 17 can reciprocate in an annular gap 23 along the axial direction of the piston 2, and an armature magnetic field exists in the gap. The lines of force of this magnetic field extend in the radial direction transverse to the moving direction of the movable coil.

In this case, the permanent magnet comprises an annular permanent magnet 24 having upper and lower magnetic poles, a soft iron annular disc 25, a solid soft iron cylinder 26 and a soft iron circular disc 27. Here, the permanent magnet and the soft iron component together form a closed magnetic circuit, that is, a closed magnetic force line circuit. Piston 2 is a support spring
28, which secures the fixed center position of the piston. Further, both ends of the support spring 28 are locked so as not to move laterally, and these ends are arranged around the protrusions 29 and 30. The elastic member 31 provided below the free displacer 3 limits the stroke of the displacer 3.

Next, the operation of the gas cycle engine having the above configuration will be described.

When an alternating current is passed through the movable coil 17 through the electrical contacts 21, 22 and the lead wires 18, 19, a Lorentz force acts on the movable coil 17 in the vertical direction due to the interaction between the permanent magnetic field in the gap 23 and electricity. Result piston 2, sleeve 16 and moving coil 17
The assembly consisting of starts vibrating. When the volume of the compression space 4 changes due to the vibration of the piston 2, the working gas enclosed in the working space is compressed and expanded, and the pressure of the gas fluctuates. Further, this pressure fluctuation causes a cyclical fluctuation of the pressure difference at both ends of the heat accumulator 7, and as a result, due to the pressure difference and the resonance of the elastic member 31, the free displacer 3 has the same frequency as the piston 2 but at a different phase. It will move.

When the piston 2 and the displacer 3 move with different phases, the working gas (for example, helium) in the working space forms a thermodynamic cycle known as the reverse Stirling cycle, and cold is generated in the expansion space 6. Let

[Problems to be solved by the invention]

Since the conventional gas cycle engine is configured as described above, there is a problem that the reaction force of the vibration of the assembly system including the piston, the sleeve, and the movable coil is directly transmitted to the cylinder, and a large vibration is generated outside. was there.

Further, in the gas cycle engine in which the assembly systems are arranged to face each other for the purpose of lowering the vibration, the number of closed magnetic circuits also increases, so that the size and weight of the gas cycle engine are large and heavy.

The present invention has been made to solve the above problems, and an object thereof is to obtain a gas cycle engine that is small in vibration during operation and is small and lightweight.

[Means for solving problems]

The gas cycle engine according to the present invention is provided with an assembly system including a piston, a sleeve, a movable coil and two closed magnetic circuits each including a permanent magnet, an annular disk, a soft iron cylinder, and a circular disk, and these are arranged to face each other. And the direction of the magnetic field in the first gap in which the first moving coil is inserted is from the inner diameter side to the outer diameter side, and the direction of the magnetic field in the second gap in which the second moving coil is inserted is the outer diameter side. The permanent magnet is arranged so as to extend from the inner side toward the inner side.

[Action]

In the gas cycle engine according to the present invention, the two assembly systems including the piston, the sleeve, and the movable coil vibrate in the opposite directions with the same phase and the same amplitude, thereby canceling each other's vibrations, resulting in low vibration. Further, by disposing the permanent magnets so that the directions of their magnetic fluxes are opposite to each other in the first gap and the second gap, the circular disk is not required, and the size and weight can be reduced.

Example of Invention

An embodiment of the present invention will be described below with reference to the drawings. First
In the figure, 1a shows a cylinder in which the free displacer 3 reciprocates. And the first piston 2a
The cooler 5 and the communication hole 32 are accommodated in the compression space 4 between the working surface of the second piston 2b, the working surface of the second piston 2b, and the working surface 3a of the displacer 3. The upper working surface 3b of the displacer 3 bounds an expansion space 6, which together with the compression space 4 constitutes the working space. The heat storage device 7 provided in the displacer 3 passes through the central hole 8 to the working medium therebelow, and also to the central hole 9 and the radial circulation duct 10.
To the working medium above it. The machine also comprises a freezer 11 as a heat exchanger for heat exchange between the expanded cold working medium and the object to be cooled.

A first piston seal 12a, 13a and a second piston seal 12b, 13b are provided between the first piston 2a and the second piston 2b and the wall of the cylinder 1b, respectively, and a seal 14, 14, is provided between the displacer 3 and the cylinder 1a. Equipped with 15. Also,
Each of the pistons 2a and 2b includes a lightweight first sleeve 16a and a second sleeve 16b made of a non-magnetic material such as synthetic resin or aluminum, and a conductive material is wound around each sleeve to form a first moving coil 17a and a first moving coil 17a. Two movable coils 17b are formed, said coils being connected to the first lead wires 18a, 19a and the second lead wires 18b, 19b which pass through the wall of the housing 20. The lead wires 18b and 19b are connected to the first electric contacts 21 provided outside the housing, respectively.
a, 22a and second electrical contacts 21b, 22b, respectively. The movable coils 17a and 17b are connected to the pistons 2a and 2b, and the first gap 23a and the second gap 23b are arranged in the axial direction of the piston.
The structure is such that it can reciprocate inside. An armature magnetic field exists in the gap in the radial direction crossing the moving direction of the movable coil, and the magnetic flux flows from the inner diameter to the outer diameter in the first gap 23a and from the outer diameter to the inner diameter in the second gap 23b. It is like this. These gap magnetic fields are supplied by a closed magnetic circuit composed of permanent magnets 24a, 24b and yokes 26a, 26b, and the first permanent magnet 24a for obtaining the direction of the magnetic force lines has an inner diameter side of S and an outer diameter side of N. The second permanent magnet 24b is magnetized with N on the inner diameter side and S on the outer diameter side.

The pistons 2a and 2b are provided with support springs 28a and 28b, which secure the fixed center position of the pistons. Also,
Both ends of the support springs 28a, 28b are locked so as not to move laterally, and these ends are arranged around the protrusions 29a, 30a and 29b, 30b. The elastic member 31 provided below the free displacer 3 limits the stroke of the displacer.

Next, the operation of the embodiment will be described. Moving coil 17a
And 17b, electrical contacts 21a, 22a, 21b, 22b and lead wires
When an alternating current is passed through 18a, 19a, 18b, 19b, Lorentz force acts on the movable coils 17a and 17b in the axial direction due to the interaction between the permanent magnetic field in the gaps 23a and 23b and the current. As a result, the assembly including the pistons 2a and 2b, the sleeves 16a and 16b and the coils 17a and 17b starts to vibrate in the left and right directions.

Now, under the condition that the characteristics of the moving coils 17a and 17b are the same and the strengths of the magnetic fields in the gaps 23a and 23b are the same, currents of the same phase and the same amplitude are applied to the first moving coil 17a and the second moving coil 17b. When flowing, the directions of the magnetic fields in the gap 23a and the gap 23b are opposite to each other, so that the coils 17a and 17b vibrate in opposite directions with the same amplitude, as a result, as shown in FIG.
The volume of the compression space 4 surrounded by the pistons 2a and 2b periodically fluctuates due to vibration. The vibration characteristic of this piston is as shown in FIG. 2 (B).

As shown in FIG. 2 (A), the permanent magnets 24a, b and the yokes 26a, b are arranged so that the magnetic fluxes in the movable coils 17a, b are opposite to each other. No magnetic flux flows through the yokes 32, 33 that connect the inner diameter side and the outer diameter side, and therefore the yokes 32, 33 in the direction of the magnetic flux can be made thin members or unnecessary, and the overall configuration can be made smaller and lighter. can do.

Here, when the volume of the compression space 4 changes due to the vibration of the piston, the working gas enclosed in the working space is compressed and expanded, and the pressure of the gas fluctuates. Further, this pressure fluctuation causes a cyclical fluctuation of the pressure difference at both ends of the heat accumulator 7, and as a result, due to the pressure difference and the resonance of the elastic member 31, the free displacer 3 has the same frequency as the piston 2 but at a different phase. It will move.

When the piston 2 and the displacer 3 move with different phases, the working gas (for example, helium) in the working space constitutes a thermodynamic cycle known as the reverse Stirling cycle, and the expansion space 6 is cooled with cold. generate.

〔The invention's effect〕

As described above, according to the present invention, since two sets of movable coils are provided and they are configured to vibrate in opposition to each other, there is an effect that an engine with less vibration can be obtained. Further, since the magnetic fields in the first gap and the second gap are oriented in opposite directions, a circular disc is not necessary and a yoke connecting the inner diameter side and the outer diameter side is not necessary, which is small and lightweight. There is an excellent effect that

[Brief description of drawings]

FIG. 1 is a sectional side view showing a gas cycle engine according to an embodiment of the present invention, and FIGS. 2 (A) and 2 (B) show the magnetic circuit of the gas cycle engine shown in FIG. FIG. 3 and FIG. 3 are sectional side views of a conventional gas cycle engine. 2a is the first piston, 2b is the second piston, 17a is the first moving coil, 17b is the second moving coil, 23a is the first gap, 23b is the second gap, 24a is the first permanent magnet, and 24b is the second permanent. magnet. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A movable coil is provided in a magnetic flux produced by a permanent magnet, and an alternating current is passed through the movable coil to vibrate a piston connected to the movable coil. In a gas cycle engine that compresses and expands, a movable coil and two pistons are provided, and a second movable coil and a second piston are arranged to face the first movable coil and the first piston, and The direction of the magnetic flux in the first gap in which the first moving coil is inserted is from the inner diameter side to the outer diameter side, and the direction of the magnetic flux in the second gap in which the second moving coil is inserted is the outer diameter side to the inner diameter side. The permanent magnet and the yoke are arranged so that the first and second pistons vibrate in mutually opposite directions, and the alternating current flowing through the first and second movable coils and the first and second Yes Gas-stroke engine, characterized in that setting the winding direction of the coil.