JP2003287302A - Piston head structure of drive compressor in refrigerator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a piston head structure of a drive compressor in a refrigerator capable of extending service lives of a stirling refrigerator and other refrigerators by facilitating adjusting work between a cylinder 6 and a piston 7, bringing an interval between the cylinder and the piston close to a non-contact seal being an ideal state, reducing required values of parts accuracy and assembly accuracy, and reducing the number of parts whose sizes are to be controlled. <P>SOLUTION: In the case that the piston head 8 part of the piston 7 is divided into a piston rod 41 and a piston cover 42, the piston head 8 of the piston 7 is divided into the piston rod 41 extending in a reciprocating motion direction and the piston cover 42 positioned between the piston rod 41 and the cylinder 6 and stored in the cylinder 6, so that the positions of the piston cover 42 and piston rod 41 can be mutually adjusted. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piston head structure of a drive compressor in a refrigerator, and in particular, a Stirling refrigerator or a pulse tube equipped with a drive compressor such as a gas compressor to generate refrigeration in a cold head. The present invention relates to a piston head structure of a drive compressor in a refrigerator and other refrigerators.

[0002]

2. Description of the Related Art A conventional refrigerator will be outlined with reference to FIG. 3, taking a Stirling refrigerator as an example. FIG. 3 is a schematic sectional view of the Stirling refrigerator 1. The Stirling refrigerator 1 has a gas compressor 2 (driving compressor) and a cold head 3.

The gas compressor 2 is for generating a refrigeration in the cold head 3 by performing a compression supply operation and a suction expansion operation of the refrigerant to the cold head 3, and a compressor case 4 composed of a pressure vessel, and the compressor case 4. Case cover 5
And. The cylinder 6 is fixed inside the compressor case 4, and the piston 7 reciprocates in the cylinder 6. The gas compressor 2 has a structure symmetrical with respect to the center line C in the drawing, and only half of the structure is shown in FIG. 3 (hereinafter, the same applies to each drawing).

The piston 7 has a piston head 8 located inside the cylinder 6, and a leaf spring mounting portion 9 extending from the piston head 8 in the axial direction, that is, in the reciprocating direction.
And, this is constructed from. The leaf spring attaching portion 9 is fixed to the center portion of the circular leaf spring 10 at the middle portion of the leaf spring attaching portion 9 and the end portion on the cover side with the fixing bolt 11.

A double-cylindrical yoke 12 is fixed to the cylinder 6 with mounting bolts 13, and a cylindrical permanent magnet 14 is mounted inside thereof. This permanent magnet 1
An annular electromagnetic coil 15 is located inside 4 and the electromagnetic coil 15 is attached to the leaf spring attachment portion 9 of the piston 7. A linear motor 16 is composed of the yoke 12, the permanent magnet 14 and the electromagnetic coil 15. In addition, York 1
The leaf springs 10 are attached at two positions of 2 by the mounting bolts 17.
To fix.

A compression / expansion chamber 18 is formed between the piston head 8 of the piston 7 and the cylinder 6, and a gas flow path 1 for a refrigerant such as helium gas is provided between the left and right cylinders 6.
9 is formed, and the gas flow path 19 communicates with the cold head 3 via the gas supply pipe 20.

The cold head 3 includes a cylinder 21 and
A displacer 23 (piston) accommodating the cold storage material 22 and a spring material 24 are provided, and the refrigerant is supplied (compressed and expanded) and the displacer 2 is out of phase with each other.
With the reciprocating movement of 3, the reverse Stirling cycle is executed to generate refrigeration.

That is, by passing an alternating current of a predetermined frequency through the electromagnetic coil 15, and by the linear motor 16
The permanent repulsion of the permanent magnet 14 and the electromagnetic coil 15 in the axial direction is caused by the elastic repulsive force of the leaf spring 10 forming a resonance system to generate the relative movement of the piston 7 and the cylinder 6, and the compression expansion chamber The pressure of the refrigerant in 18 is raised and lowered, and the pressure change of the refrigerant is supplied from the gas flow passage 91 to the cold head 3 side through the gas supply pipe 20 at a predetermined timing to cause the cold head 3 to freeze.

In the Stirling refrigerator 1 having such a structure, the cylinder inner peripheral wall surface 6A of the cylinder 6 and the piston outer peripheral wall surface 7A of the piston 7 (piston head 8) are ideal in durability and mechanical strength of the gas compressor 2. From the viewpoint of life, it is desirable to make it non-contact. However, in reality, the center line 7C of the piston 7 and the center line 6C of the cylinder 6 do not necessarily coincide with each other due to reasons such as part processing accuracy and assembly accuracy, and an ideal non-contact state cannot be achieved. There is a problem. Therefore, while processing and assembling according to the required values of component accuracy and assembly accuracy, and trying to approach the ideal state by increasing the number of parts whose dimensions should be controlled, avoiding complicated management and increased costs. There is a problem that you can not. In addition, after assembling the leaf spring 10 and the piston 7 portion, it is necessary to insert the piston 7 into the cylinder 6 and check the sliding state thereof, so that the sealing property between the cylinder 6 and the piston 7 is improved. There is a problem that the effort of adjustment increases.

As the drive type of the gas compressor 2, as shown in FIG. 3, a piston drive type in which the piston 7 is relatively moved with respect to the fixed cylinder 6 and a cylinder with respect to the fixed piston 7 are used. There is a cylinder drive type for moving 6 and FIG. 4 shows a cylinder drive type.

That is, FIG. 4 is a schematic cross-sectional view of a conventional cylinder drive type Stirling refrigerator 30. The same parts as those of the Stirling refrigerator 1 of FIG. . In this Stirling refrigerator 30, a cylindrical cylinder 31 is attached to the central portion of the leaf spring 10 by a fixing bolt 11 so as to be axially drivable, and between the cylinder head 32 and the piston 7 (piston head 8). A compression / expansion chamber 18 is formed. Further, a part of the gas flow passage 19 formed in the central shaft portion of the piston 7 and the compression / expansion chamber 18 are communicated with each other.

The plate spring mounting portion 9 of the piston 7 is fixed to the compressor case 4 by the mounting bolts 33.

In the Stirling refrigerator 30 having such a structure, the cylinder 31 is driven by the action of the linear motor 16 and the leaf spring 10 so as to reciprocate with respect to the piston 7, and the refrigerant gas is periodically supplied to the cold head 3. It is possible. However, in a sealed state in which the center line 7C of the piston 7 and the center line 31C of the cylinder 31 are aligned and the hermeticity of the compression / expansion chamber 18 is maintained at a predetermined level, the piston outer peripheral wall surface 7A of the piston 7 and the cylinder 31 of the cylinder 31 In order to realize the ideal non-contact state with the peripheral wall surface 31A as much as possible, there is a problem that the same parts machining, parts management, and adjustment work as those of the Stirling refrigerator 1 in FIG. 3 are necessary.

[0014]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and relates to a refrigerator in which a non-contact seal, which is an ideal state, can be provided between a cylinder and a piston. An object is to provide a piston head structure for a drive compressor.

Another object of the present invention is to provide a piston head structure of a drive compressor in a refrigerator, which can facilitate adjustment work between a cylinder and a piston.

Another object of the present invention is to provide a piston head structure of a drive compressor in a refrigerator, which can reduce the required values of component accuracy and assembly accuracy.

It is another object of the present invention to provide a piston head structure for a drive compressor in a refrigerator, which can reduce the number of parts whose dimensions must be controlled.

Another object of the present invention is to provide a piston head structure of a drive compressor in a refrigerator that can extend the life of a Stirling refrigerator and other refrigerators.

[0019]

That is, the present invention focuses on the fact that the piston head portion of the piston is divided into a piston rod and a piston cover, and the positions of the piston cover and the piston rod can be adjusted relative to each other. A linear motor having a permanent magnet and an electromagnetic coil, a cylinder and a piston that drive one of them with the linear motor, and a leaf spring that forms a resonance system with the linear motor. A piston head structure of a drive compressor in a refrigerator that generates refrigeration by reciprocating one of them to perform compression and expansion of a refrigerant, wherein the piston head of the piston extends in the direction of the reciprocating motion. Rod, this piston rod and the cylinder Located divided into a piston cover housed in the cylinder, a piston head structure driven compressor in the refrigerator, characterized in that the possible alignment with each other the piston cover and the piston rod.

The inside diameter of the piston cover may be slightly larger than the outside diameter of the piston rod.

The piston cover has a head portion facing the compression and expansion chamber of the refrigerant and a cylindrical portion extending in the direction of the reciprocating motion. Bolt through holes are formed in the head portion to form the piston cover. A fixing bolt for fixing the piston rod to the piston rod, and a small gap is formed between the fixing bolt and the bolt through hole in a direction perpendicular to the reciprocating direction of the piston cover. Thus, the relative positions of the piston rod and the piston cover can be adjusted.

The piston head structure according to the present invention is
It can be applied to either a piston drive type or a cylinder drive type.

In the piston head structure of the drive compressor in the refrigerator according to the present invention, the piston head portion of the piston is divided into the piston rod and the piston cover, and the positions of the piston cover and the piston rod can be adjusted relative to each other. After adjusting the center axis of the fixed side cylinder or piston and the center axis of the movable side piston or cylinder independently of each other, the cylinder and the piston can be assembled so as to be fitted to each other. Therefore, it is not necessary to perform the conventional adjustment work of assembling the respective parts on the cylinder side and the piston side and then adjusting the contact state by fitting the cylinder and piston together. Assembling work can be performed easily and at low cost without being damaged.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Next, a piston head structure 40 of a drive compressor in a refrigerator according to a first embodiment of the present invention will be described with reference to FIG. However, the same parts as those in FIGS. 3 and 4 are designated by the same reference numerals, and the detailed description thereof will be omitted. FIG. 1 is a schematic cross-sectional view showing a piston-driven Stirling refrigerator 1 and a piston head structure 40 thereof similar to the case of FIG. 3, and in the piston head structure 40, the piston head 8 of the piston 7 is It is divided into a piston rod 41 and a piston cover 42. Bolt holes 43 are formed in the piston rod 41.

The piston cover 42 has a head portion 42A which faces the compression and expansion chamber of the refrigerant and a cylindrical portion 42B which extends in the reciprocating direction. A bolt through hole 44 is formed in the head portion 42A of the piston cover 42 so that a fixing bolt 45 for fixing the piston cover 42 to the piston rod 41 can be inserted. A first slight gap 46 is formed between the fixing bolt 45 and the bolt through hole 44 in a direction perpendicular to the reciprocating direction of the piston cover 42 (piston rod 41).

Further, the outer diameter 41D of the piston rod 41
Than the inner diameter 42D of the piston cover 42 (cylindrical portion 42B)
Are formed to be slightly larger, and a second slight gap 47 is provided.

In the piston head structure 40 having such a structure, the center line 6C of the cylinder 6 is located at the center position of the compressor case 4, and the cylinder inner peripheral wall surface 6A of the cylinder 6 is concentric with the center line 6C. Assemble the compressor case 4 and the cylinder 6 so that they are located at. On the other hand, the leaf spring mounting portion 9 of the piston 7 is attached to the leaf spring 1
0 so that the center line 7C of the piston 7 coincides with the center line 6C of the cylinder 6, and the piston outer peripheral wall surface 42C of the piston 7 (cylindrical portion 42B of the piston cover 42) is concentric with the center line 7C. So that the piston rod 41 and the piston cover 42 are aligned with each other in the direction perpendicular to the reciprocating direction at the portions of the first slight gap 46 and the second slight gap 47. Fix it.

Therefore, the piston 7 is assembled in the cylinder 6 by aligning the center line 7C of the piston 7 with the center line 6C of the cylinder 6, and the piston outer peripheral wall surface 42C of the cylindrical portion 42B of the piston 7 is the cylinder inner peripheral wall surface 6A of the cylinder 6. It becomes possible to have a seal structure that is in a non-contact state as much as possible.
After assembling the piston 7 in the inside, the troublesome work of repeating the fine adjustment by observing the contact state is eliminated.
It is possible to reduce required values for component accuracy and assembly accuracy. Furthermore, it is possible to reduce the number of control size parts.

FIG. 2 is a schematic cross-sectional view showing a cylinder drive type Stirling refrigerator 30 and a piston head structure 50 thereof, similar to FIG. 4, equipped with a piston head structure 50 according to a second embodiment of the present invention. Also in the piston head structure 50, the piston head 8 of the piston 7 is divided into a piston rod 41 and a piston cover 42, similarly to the piston head structure 40 (FIG. 1) according to the above-described first embodiment. And further fixing bolt 45
And a bolt through-hole 44, a first slight gap 46 is formed, and a second slight gap 47 is formed between the piston rod 41 and the piston cover 42 (cylindrical portion 42B).

In the piston head structure 50 having such a structure, the center line 7C of the piston 7 is located at the center position of the compressor case 4, and the piston outer peripheral wall surface 42
In such a manner that C is located concentrically with the center line 7C, the piston rod 41 and the piston cover 42 are moved in a direction perpendicular to the reciprocating direction at the portions of the first slight gap 46 and the second slight gap 47. The compressor case 4 and the piston 7 are assembled by adjusting the position of each other and fixing them with a fixing bolt 45. On the other hand, when the cylinder 31 is attached to the leaf spring 10, the center line 31C of the cylinder 31 is located at the center of the leaf spring 10, and the cylinder inner peripheral wall surface 31A of the cylinder 31 is located concentrically with the center line 7C. The leaf spring 10 and the cylinder 31 are assembled as described above.

Therefore, the center line 7C of the piston 7 and the center line 31C of the cylinder 31 are aligned with each other to form the cylinder 3
1. Assemble the piston 7 to 1 and the cylindrical portion 42B of the piston 7
It is possible to have a seal structure in which the piston outer peripheral wall surface 42C of the cylinder 31 and the cylinder inner peripheral wall surface 31A of the cylinder 31 are in a non-contact state as much as possible. It is possible to eliminate the troublesome work of repeating the fine adjustment while observing the state, and it is possible to reduce the required values of component accuracy and assembly accuracy. Furthermore, it is possible to reduce the number of control size parts.

The present invention is applicable not only to the Stirling refrigerator 1 (FIG. 1) and the Stirling refrigerator 30 (FIG. 2) described above, but also to a pulse tube refrigerator which is a similar regenerator. Is.

[0033]

As described above, according to the present invention, the piston head of the piston is divided into the piston rod and the piston cover, and the positions of the piston rod and the piston cover can be adjusted. Therefore, the center line of the cylinder and the center line of the piston can be formed. Match as long as
Assembling and adjusting work can be facilitated and cost can be reduced.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a piston driven Stirling refrigerator 1 incorporating a piston head structure 40 according to a first embodiment of the present invention.

FIG. 2 is a schematic sectional view of a cylinder-driven Stirling refrigerator 30 incorporating a piston head structure 50 according to a second embodiment of the present invention.

FIG. 3 is a conventional piston-driven Stirling refrigerator 1.
FIG.

FIG. 4 is a schematic sectional view of a conventional cylinder-driven Stirling refrigerator 30.

[Explanation of symbols]

1 Piston drive type Stirling refrigerator (Fig. 3) 2 Gas compressor (drive compressor) 3 Cold head 4 Compressor case 5 Case cover 6 Cylinder 6A Cylinder 6 inner wall surface 6C Cylinder 6 center line 7 Piston 7A Piston 7 (piston head 8) piston outer peripheral wall surface 7C Piston 7 center line 8 Piston 7 piston head 9 Piston 7 leaf spring mounting portion 10 Circular leaf spring 11 Fixing bolt 12 Yoke 13 Mounting bolt 14 Cylindrical permanent magnet 15 annular electromagnetic coil 16 linear motor (yoke 12, permanent magnet 14, electromagnetic coil 15) 17 mounting bolt 18 compression / expansion chamber 19 gas passage 20 gas supply pipe 21 cylinder 22 regenerator material 23 displacer (piston) 24 spring material 30 cylinder driven Stirling Freezer (FIG. 4) 31 Cylinder 31A Cylinder inner wall surface 31C Cylinder 31 centerline 32 Cylinder head 33 Mounting bolt 40 Piston drive type piston head structure of drive compressor 2 in Stirling refrigerator 1 (first Embodiment, FIG. 1) 41 piston rod 41D outer diameter 42 of piston rod 41 piston cover 42A head 42B of piston cover 42 cylindrical portion 42C of piston cover 42 piston outer peripheral wall surface 42D of cylindrical portion 42B piston cover 42 (cylindrical portion 42B) Inner diameter (41D <42D) 43 bolt hole 44 bolt through hole 45 fixing bolt 46 first between fixing bolt 45 and bolt through hole 44
A slight gap 47 between the piston rod 41 and the piston cover 42 (cylindrical portion 42B) 50 A piston head structure of the driving compressor 2 in the Stirling refrigerator 30 of the cylinder drive type (second implementation) Form, Figure 2))

Claims (3)

[Claims] 1. A linear motor having a permanent magnet and an electromagnetic coil; a cylinder and a piston for driving one of the linear motor and the linear motor; and a leaf spring forming a resonance system with the linear motor. A piston head structure of a driving compressor in a refrigerator that generates refrigeration by performing compression and expansion of a refrigerant by reciprocating one of the cylinder or the piston, wherein the piston head of the piston is reciprocated. A piston rod extending in the direction of and a piston cover which is located between the piston rod and the cylinder and is housed in the cylinder, and the piston cover and the piston rod are positionally adjustable with respect to each other. Piston head structure of the drive compressor in the characteristic refrigerator . 2. The piston head structure for a drive compressor in a refrigerator according to claim 1, wherein an inner diameter of the piston cover is slightly larger than an outer diameter of the piston rod. 3. The piston cover has a head portion facing the compression and expansion chamber of the refrigerant, and a cylindrical portion extending in the direction of the reciprocating motion, and a bolt through hole is formed in the head portion to form a bolt through hole. A fixing bolt for fixing the piston cover to the piston rod can be inserted, and a small gap is formed between the fixing bolt and the bolt through hole in a direction perpendicular to the reciprocating direction of the piston cover. The piston head structure of the drive compressor in the refrigerator according to claim 1, wherein the piston head structure of the refrigerator is formed so that relative positions of the piston rod and the piston cover can be adjusted.