JP3257283B2 - Reciprocating compressor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reciprocating compressor used for a Stirling cycle refrigerator or the like.

[0002]

2. Description of the Related Art FIG. 9 is a side view including a partial cross section showing a conventional example of this type of reciprocating compressor. In FIG. 9, a reciprocating compressor is formed inside a frame 11, and one end of the cylinder 2 is closed by a cylinder head 21.
2 and the working space 23 on the closed side of the cylinder 22
And the piston 3 housed in the cylinder 22
1 and the piston shaft 32, and support springs 33A and 33 for supporting the piston 31 so as to be able to reciprocate in the axial direction.
B, a linear drive device 4 coupled to the frame 1 and reciprocatingly driving the piston 31 via the piston shaft 32, and a movable portion 51 coupled to an end of the piston shaft 32 opposite to the piston to detect the position of the piston 31 And a position detector 5 that performs the operation. As shown in FIG. 10, each of the support springs 33A and 33B is provided with a plurality of spiral slits in a thin plate of, for example, a beryllium copper alloy, and its central portion is connected to both ends of the piston shaft 32, and its peripheral portion is formed. Frame 1
1 and a yoke 42 of the linear drive device 4 described later, and supports the piston shaft 32 with low rigidity in the axial direction and high rigidity in the axial direction and the radial direction.

[0003] The linear drive unit 4 includes a piston shaft 32.
And a yoke 4 arranged on the inner and outer circumferences of the solenoid coil 41 with the solenoid coil 41 interposed therebetween.
2, a yoke 43 and a permanent magnet 44. When a current is supplied to the solenoid coil in one direction or the other, the piston 31 is reciprocated through the piston shaft 32.

The position detector 5 includes a movable portion 51 made of a cylindrical magnetic material, and a fixed portion 52 having a first coil and a second coil (not shown) surrounding the movable portion 51.
The change in magnetic coupling between the first coil and the second coil caused by inserting the movable portion 51 into the fixed portion 52 causes the piston 31 coupled to the piston shaft 32
Detect the position of. These components are accommodated in a sealed space formed by the frame 11, the frame 12, and the frame 13, and a working gas such as helium gas is sealed in the sealed space. Then, as shown by a broken line in FIG. 8, connection leads are pulled out from the solenoid coil 41 of the linear drive device 4 and the first and second coils of the fixed portion 52 of the position detector 5 in an airtight manner and connected to the drive circuit 6. .

The operation of this reciprocating compressor is as follows. In the state shown in FIG. 9, when power is supplied to the drive circuit 6, a unipolar current is supplied to the solenoid coil 41 of the linear drive device 4, and the piston 31 moves rightward. When the piston 31 comes to the right end of the cylinder 22, the drive circuit 6 switches the current of the solenoid coil 41 to the reverse polarity based on the signal of the position detector 5, and the piston 31 moves to the left. And this piston 31 is the cylinder 22
, The drive circuit 6 switches the current of the solenoid coil 41 to the original polarity based on the signal of the position detector 5. Hereinafter, this operation is repeated, so that the piston 31 is reciprocated in the cylinder 22, and the working gas is compressed or expanded in the working space 23. This working space 23 is a pressure guiding tube 2
Through 4, it is connected to the outside such as an expander of a Stirling cycle refrigerator.

[0006]

By the way, in this type of reciprocating compressor used in a Stirling cycle refrigerator or the like, the distance between the cylinder and the piston is more than ten in order to prevent impurities from being mixed into the working gas. A clearance seal (indicated by P in FIG. 9) having a small gap of μm is used, and it is necessary to accurately determine the position of the piston with respect to the cylinder in order to secure the small gap.

However, in the reciprocating compressor described above,
At the time of assembly (1) Coaxial error between piston and piston shaft (2) Mounting error of center of each support spring on piston shaft (3) Multiple mounting errors such as mounting error of peripheral portion of each support spring on frame etc. Accumulates, and it is not possible to measure the positional accuracy of the cylinder and piston during assembly, resulting in poor positional accuracy of the piston with respect to the cylinder, causing variations in the minute gap of the clearance seal, and lowering the performance as a reciprocating compressor. is there.

[0008] Incidentally, a method of finally measuring the minute gap between the cylinder and the piston by using an autocollimator or the like from the cylinder head side during assembly to determine the position of the piston with respect to the cylinder can be considered. Since only the gap can be measured, if there is an axial misalignment between the cylinder and the piston, the minute gap of the clearance seal varies.

An object of the present invention is to provide a reciprocating compressor having a clearance seal between a cylinder and a piston.
An object of the present invention is to provide a reciprocating compressor in which a minute gap of a clearance seal is accurately determined.

[0010]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, an invention according to claim 1 is provided with a cylinder formed inside a frame and having one end closed, and a cylinder mounted on a closed side of the cylinder. Leaving a space, and a piston inserted into the cylinder via a clearance seal and the piston shaft; a support spring coupled to the piston shaft to support the piston so as to be able to reciprocate in the axial direction; and A reciprocating compressor comprising: a linear drive device for reciprocatingly driving the piston in the axial direction through a piston; and a position detector having a movable portion coupled to an end of the piston shaft opposite to the piston. A first component comprising a cylinder having one end closed, a piston,
It is divided into a second component comprising a piston shaft, a support spring, a linear driving device and a movable portion of a position detector, and a third component comprising a fixed portion of the position detector. The cylinder has its axis formed perpendicularly with the coupling surface with the second component as a reference plane, and the piston, the piston shaft and the movable part of the position detector of the second component have their axes connected to the first component. Is formed vertically with the coupling surface of the position detector as a reference surface, a measurement frame having a displacement detector of the movable part of the position detector is attached to the second component, and the position of the movable part of the position detector is measured. The second component is loosely coupled to the first component with their coupling surfaces aligned and finely moved along the coupling surface to provide a reference position for the reference position of the movable part of the position detector. Measure the area without displacement and position the second component at the center of this area. Set to be in the second component attached firmly to the first component.

According to a second aspect of the present invention, a cylinder formed inside the frame and having both ends opened and a working space left in the center of the cylinder and inserted into the cylinder from one direction via a clearance seal. The first piston and the first piston shaft, the second piston and the second piston shaft inserted into the cylinder from the other direction through a clearance seal, and the first piston shaft. A first support spring that supports the first piston so as to be able to reciprocate in the axial direction, and a first linear drive device that drives the first piston to reciprocate in the axial direction via the first piston shaft. A first position detector having a movable portion coupled to the opposite end of the first piston shaft on the opposite side of the piston, and a second piston coupled to the second piston shaft, the second piston being axially moved; In a reciprocating compressor comprising a second support spring for reciprocatingly supporting and a second position detector having a movable portion coupled to an end of the second piston shaft opposite to the piston, A first component formed of a cylinder formed therein and having both ends opened, a first piston, a first piston shaft, a first support spring, a first linear drive device, and a first position detector A second component comprising a movable portion, a third component comprising a fixed portion of the first position detector, a second piston, a second piston shaft, a second support spring, and a second component. A fourth component comprising a linear driving device and a movable portion of a second position detector; and a fifth component comprising a fixed portion of the second position detector. The cylinder has its axis set as a reference plane with respect to the coupling surface with the second and fourth components. Vertically formed in the,
The first piston, the first piston shaft, and the movable portion of the first position detector of the second component have their axes formed perpendicularly with the coupling surface with the first component as a reference plane. The second piston, the second piston shaft, and the movable portion of the second position detector of the component of the above-mentioned components have their axes formed perpendicularly with the coupling surface with the first component as a reference plane. The measuring frame provided with the displacement detector of the movable part of the position detector is attached to each of the constituent parts of the position detector 4, and the positions of the movable parts of these position detectors are measured and set as reference positions. Each part is loosely coupled to the first component part with their coupling surfaces aligned and finely moved along the coupling surface over the entire circumference to measure an area where the reference position of the movable part of the position detector does not deviate,
The second and fourth components are located at the center of this region, and the second and fourth components are firmly connected to the first component.

According to a third aspect of the present invention, in the first or second aspect of the present invention, the second component or the fourth component is provided on the first component along the connecting surface thereof. A fine movement mechanism that finely moves over the circumference is provided.

[0013]

According to the first aspect of the present invention, the first component comprising a cylinder formed inside the frame and having one end closed, and the piston, the piston shaft, the support spring, the linear drive device, and the position detector. Divided into a second component comprising a movable component and a third component comprising a fixed component of the position detector, the cylinder of the first component and the piston, piston shaft and position of the second component are divided. Since the movable portion of the detector is formed vertically while inspecting with a three-dimensional measuring device or the like using the coupling surface of the first and second components as a reference surface, the accuracy in the middle of manufacturing is controlled. . Further, the measuring frame is attached to the second component, the position of the movable part of the position detector of the second component is measured and set as a reference position, and the second component is assigned to the first component. When the second component is finely moved over the entire circumference along the coupling surface, the reference position of the movable portion of the position detector is shifted when the cylinder and the piston come into contact with each other. By measuring an area where there is no shift in the reference position, a minute gap between the cylinder and the piston can be indirectly measured. By positioning the second component at the center of this region and firmly connecting the second component to the first component, the minute gap between the cylinder and the piston clearance seal is accurately determined.

The invention described in claim 2 shows a case of a reciprocating compressor of opposed type in which pistons are inserted from one and the other of the cylinder, and the operation is the same as that of claim 1. The invention according to claim 3 is the invention according to claim 1 or 2
Wherein a fine movement mechanism for finely moving the second component or the fourth component is provided in the first component.
Fine movement of these second or fourth components is convenient.

[0015]

FIG. 1 is a side view including a partial cross section showing an embodiment of a reciprocating compressor according to the present invention. The difference between the embodiment shown in FIG. 1 and the conventional example shown in FIG. 9 is that the periphery of the support spring 33A connected to the frame 11 is
The frame 12 connected to the frame 11 is connected to the yoke 42 of the linear drive device 4, and the peripheral portion of the support spring 33 B connected to the frame 42 of the linear drive device 4 is connected to the frame 12. At the point of joining. A first component 71, which is formed inside the frame 11 and includes a cylinder 22 having one end closed by a cylinder head 21, a piston 31, a piston shaft 32, support springs 33A and 33B, a linear drive unit 4, a frame 12 And a second component 72 composed of the movable part 51 of the position detector 5 and a third component 73 composed of the fixed part 52 and the frame 13 of the position detector 5 (see FIG. 3). Here, the axis of the cylinder 22 of the first component 71 is set high while inspecting with a three-dimensional measuring device or the like using the coupling surface A of the second component 72 with the yoke 42 of the linear drive device 4 as a reference surface. Form perpendicular to accuracy. Also,
The axis of the piston 31, the piston shaft 32 of the second component 72, and the axis of the movable portion 51 of the position detector 5 are set with the coupling surface B of the yoke 42 of the linear drive device 4 with the first component 71 as a reference surface. Similarly, it is formed vertically with high precision while inspecting with a three-dimensional measuring device or the like. Thereby, the accuracy in the middle stage of the manufacturing is managed.

Next, as shown in FIG.
A frame 85 for measurement provided with a displacement detector 84 for detecting the displacement of the movable part 51 of the position detector 5 is attached to the frame 12 with its coupling surface C facing down. FIG. 5 is a cross-sectional view taken along line HH of FIG. 4 showing details of the displacement detector 84. The displacement detector 84 includes two displacement detectors arranged on the XY axes. And the position detector 5 of this second component
Is measured by the displacement detector 84, and this position is set as the reference position of the movable part 51 of the detector 5.

Next, as shown in FIG. 6, a first component 71 is attached to an assembling frame 81, and a second component 72 (FIG. 4) in which a measuring frame 85 is connected to the first component 71.
(The state shown in FIG. 2) by combining these connecting surfaces, that is, by connecting the connecting surface B provided on the yoke 42 of the linear drive device 4 to the first position.
Lightly tighten with the bolts 14 in accordance with the connecting surface A of the frame 11 of the component 71 of the above. The assembling base 81 is provided with a fine movement mechanism 82 for finely moving the second component 72 along the coupling surface A of the first component 71, and a displacement detector 83 for the second component 72. These are brought into contact with the outer periphery of the yoke 42 of the linear drive device 4 of the second component 72. FIG.
G in FIG. 6 showing details of the fine movement mechanism 82 and the displacement detector 83.
FIG. 14 is a sectional view taken along the line -G. The fine movement mechanism 82 is constituted by a fine movement mechanism composed of four fine movement micrometers arranged at four equally-spaced parts in the circumferential direction shifted from the XY axes by 45 °.
Is composed of a displacement detector composed of two optical displacement meters arranged on the XY axes.

When the second component 72 to which the measuring frame 85 is coupled is attached to the first component 71, when the piston 31 is inserted without contacting the inner surface of the cylinder 22, the piston 31 Since no external force is applied, the movable portion 51 of the position detector 5 is maintained at the reference position. However, when the piston 31 comes into contact with the inner surface of the cylinder 22, an external force is applied to the piston 31 and the movable portion 51 of the position detector 5 becomes the reference position. It will shift from the position. Here, the second component 72 is finely moved over the entire circumference along the coupling surface A by the fine movement mechanism 82 of the assembling base 81, and an area where the reference position of the movable part 51 of the position detector 5 is not shifted is measured. Thus, the minute gap P between the cylinder 22 and the piston 31 can be measured indirectly. Then, the second component is located at the center of this region (that is, at this time, the piston 31 is located at the center of the cylinder 22), and the bolt 14 is strongly fastened and fixed.

After that, the measuring frame 85 attached to the frame 12 is removed, and the third component 73 provided with the fixing portion 52 of the position detector 5 is aligned with the connecting surfaces C and E. Connect and remove from the assembly base 81. Thus, in the reciprocating compressor of the present invention, the minute gap of the clearance seal P between the cylinder 22 and the piston 31 is accurately determined while minimizing the assembly error.

In FIG. 7, four fine movement micrometers of the fine movement mechanism 82 are provided at four equally divided places in the peripheral direction.
Three pieces may be provided at three equally divided parts in the peripheral direction. FIG. 8 shows a different example of the fine movement mechanism shown at 82 in FIG.
The fine movement mechanism 88 is provided between the outer peripheral surface 42A of the yoke 42 of the linear driving device 4 and the lower surface of the step 11A of the frame 11 provided so as to face the outer peripheral surface 42A by tightening a screw 86 in the radial direction. A wedge mechanism 87 that moves a minute distance to the second component 7 by adjusting the screw 86.
2 can be finely moved along the coupling surface of the first component.

The fine movement mechanism 88 can be conveniently mounted without being disassembled after assembly since there is no other trouble even if the fine movement mechanism 88 is mounted as it is after assembly is completed. FIG. 2 is a side view including a partial cross section showing a different embodiment of the reciprocating compressor of the present invention. The embodiment shown in FIG. 2 differs from the embodiment shown in FIG. 1 in that a cylinder 22 having one end closed by a cylinder head 21 has a frame 11 formed therein.
In place of this, a frame 16 is provided in which a cylinder 26 having both ends opened is formed, and the first and second pistons are inserted from both directions while leaving the working space 23 in the center of the cylinder 26. On the point. The working space 23 is connected to the outside through an impulse line 24, for example, an expander of a Stirling cycle refrigerator.

A first component 71 formed of the cylinder 26 formed inside the frame 16 and having both ends opened, a first piston 31, a first piston shaft 32,
A second support unit comprising the first support springs 33A and 33B, the first linear driving device 4 and the movable portion 51 of the first position detector 5.
, A third component 73 composed of the first frame 12 and the fixing portion 52 of the first position detector 5, and a second piston, a second piston shaft (not shown),
A fourth component 74 comprising a movable portion of the second support spring, the second linear drive device and the second position detector, and a fifth component 74 comprising a fixed portion of the second frame and the second position detector.
And the component 75. Others are the same as those of the reciprocating compressor shown in FIG.

The reciprocating compressor is characterized in that the vibrations of the pistons reciprocally driven to face each other in both directions cancel each other, so that the vibration is low.

[0024]

According to the present invention, in a reciprocating compressor in which a clearance seal is provided between a cylinder and a piston, a minute gap of the clearance seal is accurately determined, so that a high-performance reciprocating compressor can be obtained.

[Brief description of the drawings]

FIG. 1 is a side view including a partial cross section showing an embodiment of a reciprocating compressor according to the present invention.

FIG. 2 is a side view including a partial cross section showing a different embodiment of the reciprocating compressor of the present invention.

FIG. 3 is an explanatory diagram showing the configuration of FIG. 1;

FIG. 4 is a first explanatory view showing the assembling method of FIG. 1;

FIG. 5 is a second explanatory view showing the assembling method of FIG. 1;

FIG. 6 is a third explanatory view showing the assembling method of FIG. 1;

FIG. 7 is a fourth explanatory view showing the assembling method of FIG. 1;

8A and 8B show still another embodiment of the reciprocating compressor of the present invention, wherein FIG. 8A is a front view of a main part, and FIG. 8B is a sectional view of FIG.

FIG. 9 is a side view including a partial cross section of a conventional reciprocating compressor.

FIG. 10 is a front view of the support spring of FIG. 9;

[Explanation of symbols]

 Reference Signs List 22 cylinder 23 working space 26 cylinder 31 piston 32 piston shaft 33A support spring 33B support spring 4 linear drive device 51 movable portion 5 position detector 71 first component portion 72 second component portion 73 third component portion 74 fourth 75 Fifth component 82 Fine movement mechanism 83 Displacement detector 84 Displacement detector 88 Fine movement mechanism

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F25B 9/14 520 F04B 39/00 104

Claims (3)

(57) [Claims] 1. A cylinder formed inside a frame, one end of which is closed, a piston which leaves an operating space on a closed side of the cylinder and is inserted into the cylinder via a clearance seal, and a piston shaft of the piston. A support spring coupled to the piston shaft and supporting the piston so as to be able to reciprocate in the axial direction; and a linear drive device that reciprocates the piston in the axial direction via the piston shaft.
A reciprocating compressor comprising a position detector having a movable part coupled to an end of the piston shaft opposite the piston, a first component comprising a cylinder formed inside a frame and having one end closed; , A second component comprising a movable portion of a piston, a piston shaft, a support spring, a linear drive device and a position detector, and a third component comprising a fixed portion of the position detector. The cylinder of the component has its axis formed perpendicularly with the coupling surface with the second component as a reference plane, and the piston of the second component, the piston shaft and the movable part of the position detector have its axis fixed to the first component. A coupling surface with a component is formed vertically as a reference plane, and a measurement frame having a displacement detector of a movable part of the position detector is attached to the second component,
The position of the movable part of the position detector is measured and set as a reference position, and the second component is loosely coupled to the first component by aligning their coupling surfaces and extending along the entire circumference along the coupling surface. Slightly move, measure the area where the reference position of the movable part of the position detector is not shifted, position the second component at the center of this area, and firmly couple the second component to the first component A reciprocating compressor characterized by being made. 2. A cylinder formed inside a frame and having both ends opened, a first piston inserted into the cylinder from one direction through a clearance seal while leaving an operating space in the center of the cylinder, and A first piston shaft, a second piston inserted into the cylinder from another direction through a clearance seal, and the second piston shaft; and the first piston shaft coupled to the first piston shaft. Support spring for reciprocally moving the first piston in the axial direction, a first linear driving device for reciprocatingly driving the first piston in the axial direction via the first piston shaft, and the first piston A first position detector having a movable portion coupled to an end of the shaft opposite the piston, and a first position detector coupled to the second piston shaft and supporting the second piston so as to be able to reciprocate in the axial direction. A support spring, the second to the movable part in the counter-piston side end of the second piston shaft is coupled
Reciprocating compressor comprising: a first component formed of a cylinder formed inside a frame and having both ends opened, a first piston, a first piston shaft, and a first support; Spring, first linear drive and first linear drive
A second component comprising a movable portion of the first position detector, a third component comprising a fixed portion of the first position detector, a second piston, a second piston shaft, and a second support spring. , A fourth component comprising a movable portion of the second linear drive device and the second position detector, and a fifth component comprising a fixed portion of the second position detector. The cylinder of the component has its axis formed perpendicularly to the coupling surface with the second and fourth components, respectively, as a reference plane, and the first piston, the first piston shaft, and the first piston of the second component. The movable part of the first position detector has its axis formed perpendicularly with its coupling surface with the first component as a reference plane, and the second piston, the second piston shaft and the second piston of the fourth component. The movable part of the position detector is formed so that its axis is perpendicular to the coupling plane with the first component part as a reference plane,
A measurement frame provided with a displacement detector of the movable part of the position detector is attached to each of the second and fourth components, and the positions of the movable parts of these position detectors are measured and set as reference positions.
These second and fourth components are loosely coupled to the first component with their coupling surfaces aligned and finely moved along the coupling surface over the entire circumference, and the reference position of the movable portion of the position detector is determined. Measure the area without deviation, and place the second part in the center of this area.
A reciprocating compressor, wherein the second component and the fourth component are firmly connected to the first component with the fourth component and the fourth component positioned. 3. The reciprocating compressor according to claim 1, wherein the first component comprises a second or fourth component.
A reciprocating compressor provided with a fine movement mechanism for finely moving the constituent parts along the connecting surface over the entire circumference.