JP2003193982A - Compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To optimally perform displacement control of a piston without installing a displacement sensor to the piston. <P>SOLUTION: In this compressor, a piston 2a reciprocates by the action of an electromagnetic mechanism 4a, and the volume of a compression space 16 formed oppositely to the piston 2a varies. An AC voltage supply pattern that optimizes the reciprocator of the piston 2a is experimentally obtained in advance. An AC voltage is supplied to the electromagnetic mechanism 4a according to the supply pattern. <P>COPYRIGHT: (C)2003,JPO

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compressor, and more particularly, to a compressor in which a piston reciprocates by the action of an electromagnetic mechanism and a compression space formed opposite to the piston. The present invention relates to a compressor having a variable volume. 2. Description of the Related Art A conventional compressor of this kind is, for example,
It is described in JP-A-9-324766. In order to improve the efficiency of this compressor, the displacement waveform of the piston is measured by a sensor, and the result is fed back to control the energization of an electromagnetic mechanism that displaces the piston. However, when a displacement sensor is installed on a piston, the piston structure becomes complicated,
Combined with the necessity of feedback control, the cost of the product is increased. [0004] Therefore, the present invention has been made in view of the above circumstances, and has as its technical object to provide a compressor that does not require the provision of a displacement sensor on a piston. [0005] In order to solve the above-mentioned technical problems, the invention adopted in claim 1 is that the piston reciprocates by the action of the electromagnetic mechanism and is formed to face the piston. In a compressor in which the volume of the compression space fluctuates, an AC voltage supply pattern in which the reciprocation of the piston is optimal is stored in a storage device, and the AC voltage supply pattern is stored based on the supply pattern stored in the storage device. That is, the compressor is configured to supply the voltage. According to the first aspect of the present invention, when the use condition fluctuates only slightly, such as when a compressor is used in a cryogenic refrigerator, the load fluctuation on the compressor is small. The reciprocation of the piston is optimized, and the efficiency of the refrigerator can be improved. Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an example in which a linear compressor 1 as an embodiment of the present invention is applied as a pressure fluctuation source of a pulse tube refrigerator 20. In FIG. 1, a linear compressor 1 comprises:
First case 2a and second case 2b made of aluminum
Is provided. A cylindrical permanent magnet 3a is accommodated in the first case 2a. On the inner peripheral side of the permanent magnet 3a, a movable coil 4a is disposed substantially coaxially with the cylindrical axis of the permanent magnet 3a. The movable coil 4a includes the permanent magnet 3
a with a predetermined gap. A disk-shaped movable member 5a is connected to a front end (right end in the figure) of the movable coil 4a. A rod 6a is connected to the center of the movable member 5a. The rod 6a is connected at its front end (right end in the drawing) to the back surface of the first piston 7a, and at its rear end (left end in the drawing) to one end of a spring 8a. The other end of the spring 8a is connected to a rear end wall (left side wall in the figure) of the first case 2a. [0010] The structure inside the second case 2b is also the same as the first case 2b.
The configuration is the same as that in a. That is, the cylindrical permanent magnet 3b is housed in the second case 2b. On the inner peripheral side of the permanent magnet 3b, a movable coil 4b is disposed substantially coaxially with the cylindrical axis of the permanent magnet 3b. The movable coil 4b is arranged with a predetermined gap from the permanent magnet 3b. A disk-shaped movable member 5b is connected to a front end (left end in the figure) of the movable coil 4b. A rod 6b is connected to the center of the movable member 5b. The rod 6b has a second piston 7b at its front end (left end in the figure).
At its rear end (the right end in the figure) and one end of the spring 8b. The other end of the spring 8b
It is connected to the rear end wall (the right side wall in the figure) of the second case 2b. The movable coil 4a (4b) includes a control device 9
From 0, an alternating current is supplied via a current-carrying terminal member 80 and an electric wire 82 attached to the cylinder member 10. Moving coil 4a (4b) and permanent magnet 3a
(3b) constitutes a first electromagnetic mechanism (second electromagnetic mechanism). A circular opening 9a is formed in a front end wall (right side wall in the figure) of the first case 2a. Similarly, a circular opening 9b is formed in the front end wall (the left side wall in the figure) of the second case 2b.
Is formed. The opening 9a and the opening 9b have the same diameter.
It is formed concentrically. On the other hand, an aluminum cylinder member 10
Are a first cylinder portion 10a that houses the first piston, a second cylinder portion 11b that houses the second piston, a connection wall portion 12 that connects the first cylinder portion 11a and the second cylinder portion 11b, and a working gas passage portion. 13 and the first case 2
One end of the first cylinder portion 11a is fitted into the outer peripheral wall of the opening 9a, and one end of the second cylinder portion 11b is fitted into the outer peripheral wall of the second case 2b opening 9b. Here, the second
A method of connecting the case and the cylinder member will be described. First, the second case 2 is attached to the step portion 15b of the second cylinder portion 11b.
The opening 9b of b is extrapolated, and an annular V-groove is formed in this fitting portion. Then, this portion is welded, and a fillet is formed to form a circular V
By embedding the groove, the second cylinder portion 11b and the second case 2b are seamlessly connected, so to speak.
Thereby, a thermal / mechanical integrated connection that does not require a seal member is established between the second cylinder portion 11b and the second case 2b. Similarly, between the first cylinder portion 11a and the first case 2a, a thermal / mechanical integrated connection that does not require a sealing member is established. First cylinder part 11a and second cylinder part 1
1b is coaxially arranged about the axis L1. Therefore, the first piston 7a reciprocating in the first cylinder portion 11a and the second piston 7b reciprocating in the second cylinder portion 11b also reciprocate coaxially about the axis L1. Then, a compression chamber 16 for compressing the working gas is defined in a space surrounded by the front surface of the first piston 7a, the front surface of the second piston 7b, and the connecting wall portion 12. The working gas passage 13 has a working gas passage formed therein. One end of the working gas passage 17 opens to the connecting wall 12 defining the compression chamber 16 at the opening 17a, and the other end thereof has the other end. Freezing unit 2 described later
It is connected to 0. The refrigerating unit 20 communicates with the working gas passage 17 and has a regenerator 21 filled with a regenerator material, a cold head 22 which communicates with the regenerator 21 to generate cold, and a hollow head which communicates with the cold head 22. A pulse tube 23 formed of a stainless steel tube, and a phase adjusting mechanism 25 connected to the pulse tube 23 via a connecting tube 24 to adjust a phase difference between a pressure fluctuation and a displacement fluctuation of the working gas are mainly included. is there. In this example, the orifice 26 and the buffer tank 27 are used as a phase adjusting mechanism. A pulse tube refrigerator is constituted by the linear compressor 1 and the refrigeration unit 20 described above. The working gas passage 17 is formed in a vertical plane in FIG.
This is a configuration that communicates with No. 1. In the above configuration, the movable coils 4a, 4b
When an alternating current is applied from the control device 90, the first piston 7a and the second piston 7b
The inside of the cylinder 11a and the second cylinder 11b is
1 reciprocates along with the gas pressure in the compression chamber 16 in a sinusoidal wave. This pressure fluctuation causes the working gas passage 17
Regenerator 21, cold head 22, pulse tube 2 through
3 is transmitted. At this time, due to the action of the phase adjusting mechanism 25 constituted by the orifice 26 and the buffer tank 27, a predetermined phase difference mainly occurs between the displacement fluctuation and the pressure fluctuation of the working gas in the regenerator 21. By appropriately adjusting the phase difference, the working gas expands in the vicinity of the cold head 22 to generate cold heat, and the working gas is compressed in a portion near the working gas passage 17 of the regenerator to release heat.
That is, it acts as if heat is extracted from the vicinity of the cold head 22 to the side near the working gas passage 17 of the regenerator.
As a result, freezing occurs near the cold head 22. In the reciprocating motion of the first piston 7a, the supply of the AC voltage to the movable coil 4a is performed in a manner as shown in FIG. In other words, what kind of voltage supply pattern (voltage waveform) should be used to obtain the ideal reciprocating motion of the first piston 7a is determined by using a test compressor in which a displacement sensor is installed on the piston in advance. The measured voltage supply pattern (voltage waveform) is stored in a storage device in a nonvolatile manner. Then, the storage device is connected to the control device 90, and the control device 90 causes the movable coil 4a (4) to follow the ideal voltage supply pattern (voltage waveform).
b) supply of an AC voltage to In other words, the piston displacement shown in FIG. 3 is an ideal piston reciprocating waveform measured using a test compressor, and how the supply voltage is changed to obtain such a waveform. It is the voltage waveform that indicates whether or not to perform the operation. However, when a compressor is used as a cryogenic refrigerator, a change in operating conditions causes a small load change on the compressor. Therefore, even if the voltage supply pattern (voltage waveform) is set in advance (without feedback control) ), Which is sufficient for practical use.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory diagram of a pulse tube refrigerator driven by measurement using a compressor for testing a compressor according to an embodiment of the present invention. FIG. 2 is an enlarged view of a portion A in FIG. FIG. 3 is a graph showing a relationship between a displacement of a piston of a compressor and a voltage supplied to an electromagnetic mechanism when the apparatus of FIG. 1 is operated. [Description of References] 4a: movable coil 4b: movable coil 7b: first piston 16: second piston

Claims (1)

Claims: 1. A compressor in which a piston reciprocates by the action of an electromagnetic mechanism and the volume of a compression space formed opposite to the piston fluctuates. A compressor, wherein an optimum AC voltage supply pattern is stored in a storage device, and the AC voltage is supplied based on the supply pattern stored in the storage device.