JP2000266421A - Stirling cycle engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To drive a piston with a permanent magnet being molded easily. SOLUTION: Planar permanent magnets 20 are arranged to surround a piston 15 thus constituting a magnet group 18. An electromagnetic coil 19 is applied over the outer circumference of the magnet group 18 and fed with an AC current to generate an AC field in order to move the magnet group 18 in the axial direction thus reciprocating the piston 15 in an inner cylinder 7 in the axial direction. Since planar permanent magnets 20 are employed, molding work thereof is facilitated while suppressing warp or distortion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a Stirling cycle engine used for a cooling device or the like, and more particularly, to a driving mechanism of a piston thereof.

[0002]

Conventionally, in this type of Stirling cycle engine, for example, Japanese Utility Model Laid-Open No. 60-14 / 1985
As described in Japanese Patent Application Laid-Open No. 9806 or the like, there is known an apparatus that converts rotation of a motor or the like into reciprocating motion and drives a piston by the reciprocating motion.

However, in these Stirling cycle engines, there is a problem in that the motor becomes necessary and the whole apparatus becomes large.

Therefore, there has been proposed a so-called linear motor constituted by a permanent magnet and an electromagnetic coil, and the piston is reciprocated in the axial direction by the linear motor.

However, as shown in FIG. 9, the permanent magnet 50 used in these Stirling cycle engines usually has a shape obtained by dividing a cylindrical shape in the axial direction, that is, a circular arc-shaped permanent magnet 50. The permanent magnets 50 that are used in such a manner that they are arranged annularly in the direction are difficult to machine. In other words, since this type of permanent magnet 50 fills a mold with metal powder, compresses and sinters it, a dedicated mold corresponding to the shape of the permanent magnet 50 is required, so the mold is shared. I can't. Further, when sintering a relatively thin arc-shaped permanent magnet 50, the molded permanent magnet 50 is warped, easily deformed such as distortion, and the yield is poor, so that productivity is low and cost is increased. .

An object of the present invention is to solve the above problems and to provide a small and inexpensive Stirling cycle engine.

[0007]

A Stirling cycle engine according to the present invention comprises a piston, a drive mechanism for reciprocating the piston in the axial direction, and a displacer reciprocating in the axial direction following the reciprocating motion of the piston. Consisting of
The drive mechanism is configured by a cylindrical frame, a magnet group arranged at one end of the frame, and a coil provided close to the outer peripheral side of the magnet group, and the magnet group, It is configured by arranging substantially flat permanent magnets so as to surround the piston.

[0008] With the above-described structure, the present invention can reduce the cost of the entire apparatus by using an inexpensive substantially plate-shaped permanent magnet.

In the Stirling cycle engine according to the present invention, a magnet accommodating chamber is formed at one end of the frame, at one end of the frame, and the substantially flat permanent magnet is formed in the magnet accommodating chamber. A magnet group is formed by housing magnets.

According to the present invention, the permanent magnets are accommodated in the magnet accommodating chamber and arranged in a ring shape, whereby the cylindrical magnet group can be easily constituted, and the assembling workability can be improved. Can be improved.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS. In the figure,
Reference numeral 1 denotes an apparatus main body composed of a cylinder part 2 and a body part 3, and the cylinder part 2 includes a base part 4 made of aluminum or the like, an intermediate part 5 made of stainless steel or the like, and a tip part 6 made of copper or the like. It is configured.

The body 3 is provided inside the cylinder 2.
An internal cylinder 7 is provided which extends to a position where a displacer 8 is accommodated so as to be slidable in the axial direction. The tip of the inner cylinder 7 and the tip 6
An expansion chamber E is formed therebetween, and the inside and outside of the internal cylinder 7 are communicated by the gap 9. Also, the middle part 5
, A regenerator 10 is provided on the outer periphery of the inner cylinder 7, and a communication hole 11 is formed in the base 4 to communicate the inside and the outside of the inner cylinder 7. Heat absorbing fins 12 are provided on the outer periphery of the distal end of the inner cylinder 7, and heat radiating fins 13 are provided on the outer periphery of the inner cylinder 7 between the regenerator 10 and the communication hole 11. Then, a gap 9, a heat absorbing fin 12, a regenerator 10,
A path is formed to reach the compression chamber C in the internal cylinder 7 through the radiation fin 13 and the communication hole 11.

On the outer periphery of the base 4, an external radiating fin 14 is provided.
Is attached. A piston 15 is accommodated in the inner cylinder 7 in the body 3 so as to be slidable in the axial direction. The base end of the piston 15 is
Coaxially.

The drive mechanism 16 includes a short cylindrical frame 17.
And a magnet group fixed to one end of this frame 17 by bonding or the like
And a ring-shaped electromagnetic coil 19 provided close to the outer periphery of the magnet group 18. As shown in FIG. 3, the magnet group 18 is configured by arranging permanent magnets 20 formed in a flat plate shape in a cylindrical shape. The permanent magnet 20 is made of a rare earth, iron, boron-based permanent magnet, or the like, and is formed by sintering. The side edges 21 of the permanent magnet 20 are each formed at an equal angle, and the side edges 21 are combined with each other to form a regular polygon (a regular dodecagon in this embodiment) when viewed from the axial direction. It has a cylindrical shape. Reference numerals 22 and 23 denote spiral leaf springs, and reference numeral 24 denotes a rod for limiting the amplitude of the displacer 8.

A method of manufacturing the driving mechanism 16 in the above configuration will be described. First, as shown in FIG. 3, the side edges 21a of the magnetic material 20a before magnetization are brought into contact with each other and bonded. At this time, the side edges 21a are provided with the same angle (75 degrees in this embodiment), and the adjacent magnetic members 20a are joined at the same angle (150 degrees in this embodiment). In this manner, the magnetic members 20a are arranged and joined in a regular polygonal tubular shape (in this embodiment, a regular dodecagonal tubular shape).

Next, a strong magnetic field is applied to the magnetic material group 18a joined in a regular polygonal cylindrical shape to be magnetized. Thereby, a regular polygonal cylindrical magnet group 18 is formed. The magnet group 18 thus formed is bonded to one end of the frame 17. Then, the piston 15 is fixed coaxially with the frame 17. Further, the piston 15 is inserted into the inner cylinder 7 and the magnet group 18 is
Insert into 19. Thus, the manufacture of the drive mechanism 16 is completed.

In this embodiment constructed as described above, when an alternating current is applied to the electromagnetic coil 19, an alternating magnetic field is generated, and a force for moving the magnet group 18 in the axial direction is applied by the alternating magnetic field. By this force, the piston 15 reciprocates in the inner cylinder 7 in the axial direction. For this reason, when the piston 15 moves in the direction of the displacer 8, the gas in the compression chamber C formed between the piston 15 and the displacer 8 is compressed, and the communication hole 11, the radiation fin 13, the regenerator 10 Then, through the heat absorbing fin 12 and the gap 9, the space between the tip of the inner cylinder 7 and the tip 6 reaches the expansion chamber E and pushes down the displacer 8. On the other hand, when the piston 15 moves in the opposite direction to the displacer 8, the pressure inside the compression chamber C becomes negative, and the gas flows from the expansion chamber E to the gap 9, the heat absorbing fin 12, the regenerator 10, the heat dissipating fin 13, and the communication hole 11. Through the inner cylinder 7
To the compression chamber C, thereby pushing up the displacer 8. In such a process, a reversible cycle consisting of two isothermal changes and an equal volume change is performed,
The heat absorbing fins 12 mounted on the outer periphery of the tip of the inner cylinder 7 have a low temperature, while the external heat dissipating fins 14 mounted on the outer periphery of the base 4 have a high temperature.

When such a Stirling cycle engine is used as a refrigerator, the heat absorbing fins 12 may be attached to the inside of the refrigerator, and the external heat radiation fins 14 may be exposed outside the refrigerator to exchange heat.

As described above, in this embodiment, the permanent magnets 20 having a flat plate shape are arranged so as to surround the piston 15 to form the magnet group 18. Therefore, when the permanent magnets 20 are molded by sintering, The shape and structure of the mold can also be simplified.
Further, by forming the permanent magnet 20 into a flat plate shape, a large flat magnet can be formed, and this can be cut into a predetermined size to form the permanent magnet 20 used for the drive mechanism 16, so that the permanent magnet 20 can be formed. The fabrication of 20 is also very easy. Further, since the flat permanent magnet 20 undergoes little deformation such as warpage or distortion during molding, the yield is good and the productivity is excellent. For this reason, an inexpensive plate-shaped permanent magnet 20 can be used, so that the cost of the entire apparatus can be reduced.
Further, by making the permanent magnet 20 flat, the thickness of the permanent magnet 20 can be reduced, and the size of the apparatus can be reduced.

In this embodiment, the flat permanent magnet 20
Are arranged in an annular shape so as to surround the piston 15 and the magnet group 18
However, as shown in FIG. 4, a permanent magnet 25 having one surface formed into a flat surface and the other surface formed into a cylindrical curved surface may be used as shown in FIG.

In this case, the magnet group 26 has an inner surface formed into a regular polygonal cylindrical shape and an outer surface formed into a cylindrical shape. With this configuration, the gap between the electromagnetic coil 19 and the permanent magnet 25 can be reduced, and the piston 15 can be driven efficiently.

FIG. 5 shows a second embodiment of the present embodiment. The same parts as those of the first embodiment are designated by the same reference numerals.
Description of overlapping parts will be omitted, and only different parts will be described. Reference numeral 30 denotes a frame formed in a regular polygonal cylindrical shape. A plurality of partitioned magnet housing chambers 31 are formed on one end side of the frame 30. The magnet accommodating chamber 31 is formed in the same size and the same shape corresponding to each surface of the frame 30. A flat permanent magnet 32 is housed in the magnet housing chamber 31.
The permanent magnets 32 in the present embodiment are arranged in a regular dodecagonal cylindrical shape, similarly to the first embodiment, and 12 magnet housing chambers 31 of the same shape for housing the permanent magnets 32 are formed. Form a dodecagonal tube. Further, the permanent magnet 32 housed in the magnet housing chamber 31 is fixed by bonding or the like. In addition, as shown in FIG.
A permanent magnet 35 having one surface formed into a flat surface and the other surface formed into a cylindrical curved surface may be inserted into a magnet accommodating chamber 34 of a frame 33 having an outer periphery formed in a cylindrical shape and an inner periphery formed in a regular polygonal cylindrical shape.

In the present embodiment configured as described above, similar to the first embodiment, the magnet group 36 is formed by arranging the substantially flat permanent magnets 32 so as to surround the piston 15. The shape and structure of the mold for molding the permanent magnet 32 can be simplified, the fabrication of the permanent magnet 32 is extremely easy, and there is little deformation such as warpage or distortion of the permanent magnet 32 during molding, so the yield is good. Excellent in productivity. For this reason, an inexpensive substantially flat permanent magnet 32 can be used, so that the cost of the entire apparatus can be reduced. In addition, the frames 30, 33 are formed with magnet storage chambers 31, 34 having substantially the same shape and the same size as the permanent magnets 32, 35.
Since permanent magnets 32 and 35 are incorporated in 34, permanent magnet 3
No jig is required to make the 2 and 35 cylindrical, and the permanent magnet 3
2, 35 can be easily assembled, and assembling workability can be improved.

Although the embodiments of the present invention have been described in detail, the present invention is not limited to the above embodiments, and various modifications can be made within the gist of the present invention. For example, in the present embodiment, the magnet group is constituted by twelve permanent magnets, but may be any other number. Further, in each of the above-described embodiments, the example in which the permanent magnets are arranged adjacent to each other and arranged in an annular shape has been described. However, the configuration may be such that the permanent magnets are arranged apart from each other. In the second embodiment,
The permanent magnets may be held by the elasticity of the frame or the like, not by adhesion. Furthermore, as the shape of the permanent magnet,
As shown in FIG. 7, a permanent magnet 40 having the other surface (inner surface) formed as a cylindrical curved surface and the other surface (outer surface) formed as a plane is adjacent to a magnet group 41.
With this configuration, the inner surface of the magnet group 41 becomes cylindrical, and the gap between the piston 15 and the permanent magnet 40 can be set smaller. Therefore, the diameter of the main body 1 can be reduced, that is, the size can be reduced. Further, as shown in FIG. 8, when the magnet group 46 is formed by superposing an arc-shaped permanent magnet 45 on the other surface (outer surface) of the permanent magnet 40 shown in FIG. 7, the inner surface and the outer surface of the magnet group 46 are cylindrical. It can be formed in a shape.

[0025]

According to the Stirling cycle engine of the present invention,
A piston, a drive mechanism that reciprocates the piston in the axial direction, and a displacer that reciprocates in the axial direction following the reciprocation of the piston, wherein the drive mechanism is a cylindrical frame; A magnet group arranged at one end of the frame and a coil provided close to the outer peripheral side of the magnet group, and the magnet group is formed by arranging a substantially flat permanent magnet in a cylindrical shape. By using an inexpensive substantially flat plate-shaped permanent magnet, the entire apparatus can be made inexpensive.

In the Stirling cycle engine according to the present invention, a magnet housing is formed at one end of the frame, and the substantially flat permanent magnet is housed in the magnet housing. By arranging the permanent magnets in the magnet housing chamber and arranging them in a ring shape, a cylindrical magnet group can be easily configured, and assembling workability can be improved.

[Brief description of the drawings]

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

FIG. 2 is a sectional view taken along the line AA in FIG.

FIG. 3 is a perspective view of the permanent magnet.

FIG. 4 is a perspective view of another permanent magnet according to the embodiment.

FIG. 5 is a sectional view of a frame showing a second embodiment of the present invention.

FIG. 6 is a cross-sectional view of a frame showing another embodiment of the present invention.

FIG. 7 is a perspective view showing a modification of the permanent magnet of the present invention.

FIG. 8 is a perspective view showing another modification of the permanent magnet of the present invention.

FIG. 9 is a perspective view of a conventional permanent magnet.

[Explanation of symbols]

 8 Displacer 15 Piston 16 Drive mechanism 17, 30, 33 Frame 18, 26, 36, 41, 46 Magnet group 19 Electromagnetic coil 20, 25, 32, 35, 40, 45 Permanent magnet 31, 34 Magnet accommodation room

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Takeshi Suzuki 2084 No. 2 Kata, Nishiota, Oda, Yoshida-cho, Nishikanbara-gun, Niigata Prefecture Twin Bird Industry Co., Ltd.

Claims (2)

[Claims] A piston, a drive mechanism for reciprocating the piston in the axial direction, and a displacer reciprocating in the axial direction following the reciprocation of the piston;
The drive mechanism is configured by a cylindrical frame, a magnet group arranged at one end of the frame, and a coil provided close to the outer peripheral side of the magnet group, and the magnet group, A Stirling cycle engine, wherein a substantially flat permanent magnet is arranged so as to surround the piston. 2. A magnet group formed at one end of the frame, wherein a magnet housing is formed, and the substantially flat permanent magnet is housed in the magnet housing. Stirling cycle agency.