JP3072280B2 - 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 compressor, and more particularly to a compressor suitable for use in a small refrigerator such as a pulse tube refrigerator.

[0002]

2. Description of the Related Art In recent years, application studies of devices using a so-called high-temperature superconducting substance, which generates a superconducting phenomenon near liquid nitrogen temperature (77 K), have attracted attention. When applying such a device using a high-temperature superconducting material to various products, the device is simply configured to contain the fluid in the pulse tube and the regenerator, so that it is easy to reduce the size and compress the fluid. -The above-mentioned pulse tube refrigerator having features such as the ability to externally attach a pumping / suctioning device for a fluid that causes expansion is attracting attention, and various improvements are being developed.

[0003] The basic principle of this type of pulse tube refrigerator is that a gas in contact with a cooling section formed at the end of the regenerator is expanded to absorb heat from a cooled object placed in the cooling section.
By displacing the absorbed gas in the direction of the regenerator and performing a series of heat exchange cycles with the process of compressing and releasing the heat to the regenerator, the heat taken from the cooling unit is stored in the regenerator and stored in the outward direction. It is understood that a heat flow that is sequentially carried out is generated to release heat and cool the cooling unit to an extremely low temperature.

FIG. 5 shows a conventional orifice-type or capillary-type pulse tube refrigerator with reference to the prior art. The pulse tube refrigerator 10 ′ includes a compressor 1 having a pressure chamber for pumping and sucking a fluid at a predetermined cycle, a regenerator 2, which communicates with the pressure chamber of the compressor 1 and is filled with a regenerator material, Pulse tube 4 provided in communication with the vessel 2 and filled with fluid
And a cooling unit 3 formed at a connection end of the regenerator 2 and the pulse tube 4, and a buffer tank 6 arranged in series with the pulse tube 4 via an orifice or a thin tube (capillary) 5. Have been.

In such a pulse tube refrigerator 10 ′, the piston 1 b reciprocates in the cylinder 1 a of the compressor 1, thereby repeatedly compressing and expanding the fluid in the pulse tube 4 via the regenerator 2. Do and piston 1
By providing a predetermined phase difference (ideally 90 degrees) between the movement of b and the compression / expansion of the fluid, the cooling unit 3 formed at the connection end of the regenerator 2 and the pulse tube 4 and the fluid And heat exchange is similarly performed in the regenerator 2, and the heat removed from the cooling unit 3 is transmitted to the outside and discharged.

Here, the orifice or capillary 5 has a function of controlling the fluid flowing into and out of the buffer tank.
The phase difference between the movement of the piston 1a and the compression / expansion of the fluid is controlled. By the way, the compressor applied to the pulse tube refrigerator as described above is required to have a function of giving a predetermined amplitude (phase) to the fluid in the pulse tube. A so-called Gifford-McMahon type (GM type) compressor is used in which a plurality of valves are combined.

[0007]

In the GM type compressor as described above, the pressure of the fluid is controlled by controlling the fluid delivered and sucked from the compressor by a valve.
Although the suction cycle and the pressure waveform can be made ideal, it is necessary to attach a valve to the compressor body, and there is a problem that the refrigerator becomes large.

Further, a piston constituting a GM type compressor,
Since the crank and the like slide, and the valve that controls the fluid has sliding parts and packing, the durability of the device is poor due to wear and the like, and it is difficult to apply it to long-term high-speed operation. Have. An object of the present invention is to solve the above-described problems, to have high durability, and to be easy to miniaturize,
For example, it is an object of the present invention to provide a compressor that can increase the cooling efficiency when used in a pulse tube refrigerator.

[0009]

In order to achieve the above-mentioned object, the invention according to claim 1 is characterized in that a cylinder having one end sealed and filled with a fluid, and a cylinder provided inside the cylinder and having a predetermined cycle. A piston that performs reciprocating motion, a drive mechanism that imparts the predetermined reciprocating motion to the piston via a shaft connected to the piston, a pressure chamber formed by one end of the cylinder and the piston, A communication passage communicating with an outer peripheral portion of the piston, and first and second openings that are opened in a side wall of the cylinder and communicate with the communication passage in accordance with reciprocation of the piston ;
The fluid flows out of the compressor (the cylinder) through the communication passage.
It is a compressor for cooling the pulse tube installed in the section .

According to a second aspect of the present invention, in the compressor according to the first aspect, when the pressure in the pressure chamber accompanying the reciprocating motion of the piston is in the first state, The second opening portion communicates with the communication passage and sucks the fluid when the pressure in the pressure chamber is in a second state, in communication with the communication passage. I have.

According to a third aspect of the present invention, in the compressor according to the second aspect, the first state is a state in which the pressure in the pressure chamber is near a maximum value, and the second state is a state in which the pressure in the pressure chamber is near a maximum value. The pressure in the pressure chamber is in a pressure state near a minimum value. Further, the communication passage is configured as follows:
4. The compressor according to claim 1, further comprising a flow control means for arbitrarily controlling a flow rate of the fluid sent out and sucked through the first and second openings. .

Further, according to a fifth aspect of the present invention, in the compressor according to the first, second, third or fourth aspect, the piston extends along the outer periphery at a position on the outer periphery side of the communication passage. It is characterized by having an existing groove. According to a sixth aspect of the present invention, in the first, second, third, fourth, or fifth aspect, the compressor is a linear compressor.

That is, the present invention provides a piston type compressor, comprising: a cylinder having one end sealed; a communication path communicating with the pressure chamber side and the outer peripheral side of the piston; By having individual openings (first opening and second opening) that are in communication with the outer peripheral side of the communication passage and communicate with each other, when the pressure in the pressure chamber becomes maximum, the communication passage and the first opening are formed. The fluid corresponding to the pressure is pumped through the section, and when the pressure in the pressure chamber is minimized, the communication path and the second
Thus, a fluid corresponding to the pressure can be sucked through the opening, so that a pulse-shaped pressure waveform equivalent to that of the GM compressor can be output at a predetermined timing.

Further, when the linear drive system is adopted in the compressor of the present invention, as shown in the prior art, the compressor is formed on the piston without having a structure for deteriorating the durability of the sliding contact portion and the packing. Since the valve function can be realized by the reciprocating motion of the communication passage and the piston, the size of the device can be reduced, the durability can be increased, and the device can be favorably applied to high-speed operation.

Therefore, when the compressor of the present invention is used as a fluid control means of a pulse tube refrigerator, it is possible to realize an ideal pumping / suction cycle and a pressure waveform while realizing a compact and high durability device. be able to. Further, by providing the flow control means in the communication path, the flow rate of the fluid pumped and sucked through the first opening and the second opening can be adjusted without increasing the scale of the apparatus. For example, the valve function and the flow rate adjusting function can be added to the piston by setting the flow path diameter of a part of the communication path to a predetermined value in advance, so that the cooling capacity can be improved while reducing the size of the device. be able to.

Further, by providing an opening on the outer peripheral side of the communication passage provided in the piston in a groove formed along the outer periphery of the piston, the first and second openings provided in the communication passage (groove) and the cylinder side wall are provided. 2 can be easily communicated with the opening, and the pressure balance on the outer periphery of the piston can be uniformly maintained to prevent contact and friction with the cylinder. Can be adjusted.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a compressor according to the present invention will be described below with reference to FIG. As shown in FIG. 1, a compressor 1 of the present embodiment is configured such that a linear drive type compression unit (hereinafter, referred to as a compression unit) is housed in a cylindrical outer case. The compression unit includes a cylinder 1a, a piston 1b, a shaft 1c, an elastic member 1
d, a coil 1f, a yoke 1g, a permanent magnet 1h, and the like.

The cylinder 1a is provided integrally with the outer case, is sealed at one end (left side in the drawing), and is filled with a fluid. The piston 1b is housed in the cylinder 1a and reciprocates at a predetermined cycle. Here, cylinder 1
a space formed by one end of the piston a and the piston 1b is referred to as a pressure chamber 1e.
A predetermined pressure is applied to the fluid filled in e.

One end of the shaft 1c is connected to a piston 1b at one end, and the other end of the shaft 1c is a leaf spring so that the shaft 1c is flexible in the direction in which the shaft 1c extends and rigid in the direction perpendicular to the shaft 1c. The elastic member 1d supports the outer case. The coil 1f is supported by a support member extending from between one end and the other end of the shaft 1c.
It is loosely inserted and held so as to face the permanent magnet 1h provided in the groove of the yoke 1g formed integrally with the outer case.

The piston 1b is provided with a communication passage 1i for communicating the outer periphery of the piston 1b facing the side wall of the cylinder 1a with the pressure chamber 1e, and the side wall of the cylinder 1a extends to the outside of the compressor 1. Openings (first and second openings) are provided in which one ends of the first flow path 7a and the second flow path 7b communicate with each other. Here, the openings (first and second openings) provided on the side wall of the cylinder 1a are provided such that the opening positions of the first flow path 7a and the second flow path 7b are shifted in the movement direction of the piston 1b. Have been.

The communication path 1 provided in the piston 1b
The configuration of i will be described later. In the compressor 1 having such a configuration, by passing an alternating current through the coil 1f, the shaft 1c and the piston 1b supported by the elastic member 1d reciprocate at a predetermined cycle according to the frequency of the alternating current. Next, the operation of the compressor of this embodiment will be described with reference to FIG.

First, when an alternating current is applied to the coil 1f of the compressor 1, the piston 1b reciprocates at a predetermined cycle in accordance with the cycle of the applied alternating current, and compresses and compresses the fluid in the pressure chamber 1e.
Repeat the expansion. At this time, as shown in the timing chart of FIG. 2, when the piston 1b advances toward one end of the cylinder 1a (leftward in FIG. 1), the fluid in the pressure chamber 1e is compressed and the internal pressure increases.

Then, when the internal pressure rises at a predetermined timing, for example, near the maximum pressure (t3,
At t7), the position of the piston 1b (the position on the outer peripheral side of the communication passage 1i) matches the position of the first flow path 7a,
A fluid having a pressure corresponding to the internal pressure of the pressure chamber 1e is sent out of the compressor 1 via the communication passage 1i and the first flow passage 7a.

Next, when the piston 1b advances toward the other end of the cylinder 1a (to the right in FIG. 1), the fluid in the pressure chamber 1e expands and the internal pressure decreases. Then, at a predetermined timing of the descending stroke of the internal pressure, for example, when the pressure becomes near the minimum pressure (t1, t5), the position of the piston 1b (the position on the outer peripheral side of the communication passage 1i) and the position of the second flow path 7b are determined. Are matched, a fluid having a pressure corresponding to the internal pressure of the pressure chamber 1e is sucked from the outside of the compressor 1 via the communication passage 1i and the second flow path 7b.

Further, the predetermined timing (t3,
In the ascending and descending strokes other than t7 and t1, t5), the communication path 1h provided in the piston 1b is shut off without communicating with any of the first flow path 7a and the second flow path 7b. However, the compressor 1 does not send out or suck the fluid, and is affected by the pressure state at the previous timing.

As a result, the fluid delivered and sucked from the compressor 1 has a pulse-like pressure waveform as shown at the bottom of the timing chart of FIG. 2, and is equivalent to the GM type compressor shown in the prior art. The output characteristics of a piston-type compressor (reciprocating compressor) without adding a valve, etc.
Can be realized by: In this case, the durability can be improved while the device configuration is small and simple as compared with the GM type compressor.

Next, the piston 1b applied to this embodiment
Will be described in detail with reference to FIG. Piston 1
As shown in FIG. 1, the communication passage 1 i provided in b may be formed so as to communicate at least the outer peripheral portion of the piston facing the side wall of the cylinder 1 a and the pressure chamber 1 e.

In particular, the outer peripheral side of the piston of the communication passage 1i is moved at the aforementioned predetermined timing at the first flow path 7a or the second flow path 7a.
3 (a) and 3 (b) so that fluid can flow into and out of the pressure chamber 1e appropriately and reliably in communication with the flow path 7b.
As shown in the figure, inside the groove 1j provided along the outer periphery of the piston 1b, the piston outer peripheral side of the communication passage 1i is provided.

As described above, by providing the outer peripheral side of the communication passage 1i in the groove 1j formed along the outer periphery of the piston, the communication between the first passage 7a or the second passage 7b and the communication passage 1i is established. The communication state can be easily set without considering the rotation direction of the piston 1b, and the pressure balance on the outer periphery of the piston can be uniformly maintained to prevent contact and friction with the cylinder 1a. The example compressor 1 can be easily manufactured and adjusted.

The shape of the communication passage 1i is shown in FIGS.
(A) As shown in FIG.
As shown in the figure, the light guide may be provided in a substantially L-shape.
In short, when the communication path 1i and the first flow path 7a or the second flow path 7b communicate with each other at a predetermined timing, the pressure chamber 1
It goes without saying that the communication passage 1i having another shape may be used as long as the fluid of e can be flowed in and out well.

As another configuration of the communication passage 1i, a communication passage 1i formed by drilling a hole in the piston 1b is as follows.
By setting the flow path diameter so as to achieve a desired flow rate in advance, it is possible to add a flow rate control function for controlling the flow rate of the fluid sent and sucked from the compressor 1 without providing a flow rate adjusting valve or the like. Thus, it is possible to realize a compressor that sends and sucks a fluid at a predetermined flow rate with a more compact configuration.

Next, an example in which the compressor according to the present invention is applied to a pulse tube refrigerator will be described with reference to FIG. The same components as those of the compressor shown in FIG. 1 and the configuration of the pulse tube refrigerator shown in FIG. 5 are denoted by the same reference numerals, and description thereof will be omitted. As shown in FIG. 4, the pulse tube refrigerator 10 includes a compressor 1 as a fluid control unit, a regenerator 2, a pulse tube 4, a cooling unit 3, a thin tube 5, a buffer tank 6, A flow path 7a and a second flow path 7b;
Is configured.

The compressor 1 has a single compression unit housed in a cylindrical outer case, as in the above-described embodiment.
A first flow path 7a and a second flow path 7b, one end of which communicates with the piston 1b and the side wall of the cylinder 1a.
Is provided. Here, as described above, the first flow path 7a and the second flow path 7b coincide with the opening (or the groove 1j) on the outer peripheral side of the communication path 1i provided in the piston 1b at a predetermined timing. Are formed so as to communicate with each other. The other ends of the first flow path 7a and the second flow path 7b are commonly connected to the other end of the regenerator 2 having the cooling part 3 formed on one end.

In such a pulse tube refrigerator 10,
An alternating current is passed through the coil 1f of the compressor 1 and the piston 1b
Is reciprocated at a predetermined cycle, so that a fluid having a pressure waveform equivalent to that of the timing chart shown in FIG. 2 is supplied from the compressor 1 to the regenerator via the first flow path 7a and the second flow path 7b. 2 is sucked and sent to the other end side. In addition,
In the embodiment described above, a single linear compressor having only a single piston has been described as an example. However, the present invention is not limited to this, and two sets of compression units are arranged to face each other. The present invention may be applied to a so-called piston opposed linear compressor.

In this case, a first communication passage communicating with each piston in correspondence with the first flow path 7a for sending out a fluid,
In addition, a second communication path that communicates with the second flow path 7b that sucks the fluid may be individually provided. According to such a configuration, since vibrations caused by the reciprocating motion of the piston can be offset each other, when applied to a pulse tube refrigerator, vibration transmitted to the cooling unit is suppressed,
Deterioration of the characteristics of the superconducting device can be prevented.

[0036]

According to the compressor of the present invention, the cylinder having one end sealed, the communication passage communicating with the pressure chamber side and the outer peripheral side of the piston, and the communication when the reciprocating motion of the piston is at a predetermined timing. By having individual openings (a first opening and a second opening) that communicate with the outer peripheral side of the passage in a consistent manner,
When the pressure in the pressure chamber becomes maximum, a fluid corresponding to the pressure is pumped through the communication path and the first opening, and when the pressure in the pressure chamber becomes minimum, the communication path and the second opening are opened. Since the fluid corresponding to the pressure can be sucked through the pressure, a pulse-shaped pressure waveform equivalent to that of the GM compressor can be output at a predetermined timing.

Further, by adopting a linear drive system in the compressor of the present invention, as shown in the prior art,
The valve function can be realized by the reciprocating motion of the piston and the communication passage formed in the piston without having a configuration that deteriorates the durability such as the sliding contact portion and the packing.
The present invention can be applied to high-speed operation with high durability while reducing the size of the device.

Therefore, when the compressor of the present invention is used as a fluid control means of a pulse tube refrigerator, it is possible to realize an ideal pumping / suction cycle and pressure waveform while realizing a compact and high durability device. be able to.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing one embodiment of a compressor according to the present invention.

FIG. 2 is a timing chart showing opening / closing timing of a flow path and a pressure waveform in the compressor according to the present invention.

FIG. 3 is a perspective view showing a shape of a piston applied to the compressor of the embodiment.

FIG. 4 is a schematic configuration diagram showing an example in which the compressor according to the present invention is applied to a pulse tube refrigerator.

FIG. 5 is a schematic configuration diagram illustrating an example of a pulse tube refrigerator according to the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor 1a Cylinder 1b Piston 1c Shaft 1d Elastic member 1e Pressure chamber 1f Coil 1g Yoke 1h Permanent magnet 1i Communication path 1j Groove part 2 Regenerator 3 Cooling part 4 Pulse tube 5 Orifice 5 'Capillary tube 6 Buffer tank (Flow path means) 7b Second flow path (flow path means) 10, 10 'pulse tube refrigerator

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F25B 1/02 F25B 9/00-9/14 F04B 35/04 F04B 39/10

Claims (6)

(57) [Claims] 1. A cylinder having one end sealed and filled with a fluid, a piston installed in the cylinder and reciprocating at a predetermined cycle, and a shaft connected to the piston. A drive mechanism for imparting the predetermined reciprocating motion to a piston; a communication path communicating one end of the cylinder and a pressure chamber formed by the piston with an outer peripheral portion of the piston; A first and a second opening communicating with the communication passage with the reciprocating movement of the piston, wherein the fluid is supplied to the cylinder via the communication passage.
Tube refrigerator that cools the pulse tube installed outside
Use compressor. 2. The first opening, when the pressure in the pressure chamber accompanying the reciprocating motion of the piston is in a first state, communicates with the communication passage to send out the fluid, The compressor for a pulse tube refrigerator according to claim 1, wherein the opening communicates with the communication passage to suck the fluid when the pressure in the pressure chamber is in the second state. 3. The first state is a state in which the pressure in the pressure chamber is near a maximum value, and the second state is a state in which the pressure in the pressure chamber is near a minimum value. The compressor for a pulse tube refrigerator according to claim 2, wherein: 4. The apparatus according to claim 1, wherein said communication path has a flow control means for arbitrarily controlling a flow rate of said fluid sent out and sucked through said first and second openings. 4. The compressor for a pulse tube refrigerator according to 2, 3 or 4. 5. The pulse tube according to claim 1, wherein the piston has a groove extending along the outer circumference at a position on the outer circumference side of the communication path.
Compressor for refrigerator . 6. The pulse tube according to claim 1, wherein said compressor is a linear compressor.
Compressor for refrigerator .