JPH09264262A - Linear compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent break of a device beforehand by providing with an abnormal displacement detecting means for applying energizing force to a bottom dead point side on a piston and also detecting contact of a movable body when the piston which is reciprocating-driven by a linear motor within a setting maximum range or more, and controlling current-carrying on the basis of the detecting signal. SOLUTION: In a linear motor 11, on the outer peripheral part of a bobbin 8 to which a piston 5 is connected, an electromagnetic coil 15 is wound on a position opposed to a magnet 13 formed integratedly with a yoke 2 in which a cylinder 4 is fixed to an inner circumferential part, A.C. current is energized from a power supply device 17, and thereby, the bobbin 8, namely, the piston 5 is performed reciprocating motion, and gas boosted up in a compressor 6 is discharged. In this case, a coil spring 21 for energizing the bobbin 8 downward when the piston 5 is moved to a top dead point side within a setting maximum range or more, is arranged on a surface opposed to the bobbin 8 of the yoke 2, and current-carrying of the electromagnetic coil 15 is broken in the case where contact of the coil spring 21 of the bobbin 8 is detected in an abutting detecting circuit 22.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear compressor for compressing gas and supplying the compressed gas to the outside by reciprocating a piston fitted in a cylinder by a linear motor.

[0002]

2. Description of the Related Art In recent years, a linear compressor has been developed as a mechanism for compressing and supplying a refrigerant gas in a refrigeration system. For example, as shown in FIG. 2, a closed housing 101, a cylinder 102 formed in the housing 101, and a piston that is reciprocally fitted in the cylinder 102 and defines a compression chamber 103 in the internal space of the cylinder 102. 104 and a linear motor 105 as a drive source for reciprocally driving the piston 104. still,
In FIG. 2, the housing 101 and the cylinder 102 are integrally formed, and the magnetic frame is made of low carbon steel. And
In the linear motor 105, an annular permanent magnet 106 is arranged concentrically outside the cylinder 102 and fixed to the housing 101. The magnet 106 and the housing 10
1. With the magnetic circuit including the magnetic frame of the cylinder 102, a cylindrical gap 107 concentric with the center of the cylinder 102 is formed.
To generate a magnetic field B. A cylindrical movable body 108 having a bottom and made of resin is integrally fixed to the piston 104 at the center of the gap 107. The movable body 108 and a coil spring for elastically supporting the piston 104 in a reciprocating manner. The piston spring 109 is the housing 10
It is fixed at 1.

A magnet 106 is provided on the outer periphery of the movable body 108.
The electromagnetic coil 110 is wound at a position facing
By passing an alternating current of a predetermined frequency through the lead wire 111, the coil 104 and the movable body 108 are driven by the action of the magnetic field passing through the gap 107 to reciprocate the piston 104 in the cylinder 102, and the compression chamber 103 The gas pressure is generated at a predetermined cycle.

On the other hand, FIG. 3 shows a typical refrigeration system.
As shown in FIG. 1, a hermetic refrigeration system in which a linear compressor 121 (compressor), a condenser 122, an expansion valve 123, and an evaporator 124 are connected by a gas flow path 125 is known. The refrigerant gas vaporized in 124 is sucked through a gas flow path 125 and compressed to a high pressure, and the high pressure refrigerant gas is discharged to a condenser 122 through a gas flow path 125.

Therefore, as shown in FIG. 2, the compression chamber 10
A gas passage 125 outside the housing 101 is connected to the valve 3 via a valve mechanism 112 provided in the housing 101. The valve mechanism 112 allows only a suction valve 112 a that allows only the refrigerant gas to be sucked from the evaporator 124 via the gas flow path 125, and allows only the refrigerant gas to be discharged to the condenser 122 through the gas flow path 125. It is composed of a discharge valve 112b. The suction valve 112a is provided with a low-pressure gas passage 125.
Is a valve that allows gas to flow in the direction of the compression chamber 103 depending on the pressure difference of the refrigerant gas between the compression chamber 103 and the compression chamber 103. Also, the discharge valve 1
12b is directed toward the high pressure side gas flow passage 125 by the pressure difference of the refrigerant gas between the compression chamber 103 and the high pressure side gas flow passage 125 so that the refrigerant gas is opened when the pressure of the refrigerant gas in the compression chamber 103 becomes equal to or higher than a certain pressure. It is a valve that allows gas to flow out. still,
Both the suction valve 112a and the discharge valve 112b are valves that are biased by a leaf spring.

With the above structure, the suction valve 1 is used in the conventional device.
The refrigerant gas sucked from 12a is compressed to a high pressure in the compression chamber 103 and then supplied to the condenser 122 via the discharge valve 112b.

[0007]

In the conventional linear compressor 121, the maximum amplitude range of the piston is set so that the compression efficiency is improved as much as possible.
The top dead center position of 04 is designed to be close to the top wall of the cylinder 102. However, as described above, the linear compressor 121 is elastically supported only by the piston spring 109 with respect to the housing 101, and therefore the piston 104 is not supported due to a sudden load change.
Moves to the top dead center side beyond the set maximum range, and cylinder 10
The collision with the upper wall of No. 2 and the movable body 108 often collided with the magnetic frame.

As a result, the movable body 108 and the valves 112a and 112b may be broken or the lead wire 111 may be broken due to the collision. As a countermeasure, piston 1
It is conceivable to stop the supply current to the electromagnetic coil 110 when the abnormal displacement of 04 occurs, but even if the supply current is stopped by inertia, the movement of the piston 104 cannot be stopped immediately, and the above-mentioned problem still remains. Had.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a linear compressor in which destruction and failure of the device due to abnormal displacement of the piston are prevented, and reliability and durability of the device are improved. It is provided.

[0010]

SUMMARY OF THE INVENTION The present invention is directed to a cylinder provided in a housing, a piston fitted in the cylinder so as to reciprocate, and defining a compression chamber in the cylinder, and a piston at the center. A bottomed cylindrical movable body integrally fixed to the magnet is disposed in a gap formed in a part of a magnetic circuit composed of a magnet and a magnetic frame, and a predetermined frequency is applied to an electromagnetic coil wound around the outer periphery of the movable body. A linear motor that reciprocally drives the piston by the supply of alternating current, a power supply device that supplies drive power to the electromagnetic coil, a piston spring that elastically supports the piston in a cylinder so that the piston can reciprocate, and the piston. When the robot moves to the top dead center side by more than the set maximum range, it comes into contact with the movable body to apply an urging force to the bottom dead center side of the piston and to detect contact with the movable body. A position detecting means, based on the contact detection signal from the abnormal displacement detecting means, and control means for controlling the supply output of the power supply device, a linear compressor provided with a.

By using this structure, when an abnormal displacement of the piston occurs, the drive power to the electromagnetic coil is immediately controlled and the displacement force of the piston and the movable body toward the top dead center of the piston is absorbed. Does not collide with the cylinder to destroy the valve or the like, or the movable body does not collide with the magnetic frame to be destroyed.

Further, preferably, the movable body is made of resin, and an annular metal plate is fixed to a contact portion with the abnormal displacement detection means, and the abnormal displacement detection means includes the movable body and the movable body. An electric conductor that abuts and gives an urging force to the bottom dead center side of the piston, and when the electric conductor contacts the metal plate, forms an electric closed circuit to detect contact with the movable body. A contact detection circuit.

By using this structure, the movable body can be structurally reinforced and the contact between the abnormal displacement detection means and the movable body can be reliably detected. Further, the control means stops the supply of drive power from the power supply device based on the contact detection signal from the abnormal displacement detection means.

By using this structure, the driving power supply to the electromagnetic coil is stopped, and the displacement force of the piston and the movable body can be limited to the inertia force. In addition, the electric conductor is composed of a coil spring made of metal.

By using this structure, the abnormal displacement detecting means can be made into a simple structure, and the linear compressor can be reduced in size and weight.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the linear compressor according to the present invention will be described below with reference to the drawings.
Note that the same components as those of the above-described conventional device are denoted by the same reference numerals, and detailed description of these portions will be omitted.

The linear compressor of the present invention is used as a compressor of a closed refrigeration system as shown in FIG. As a linear compressor, as shown in FIG.
And holds the linear compressor as an enclosed space. This housing 1 is a non-magnetic bottomed cylindrical body, and an upper wall 2 made of low carbon steel as a magnetic frame (yoke) is formed at the upper end opening thereof. A cylinder fitting hole 3 extending in the vertical direction is formed through the center of the yoke 2, and a bottomed cylindrical cylinder 4 made of stainless steel as a non-magnetic material is fitted into the cylinder fitting hole 3. Have been combined.

A piston 5 is slidably fitted in the cylinder 4, and a compression chamber 6 serving as a compression space for refrigerant gas is defined by the cylinder 4 and the piston 5. The cylinder 4 is provided with a valve mechanism 7 for connecting to an external gas flow path 125.
7b is a suction valve for sucking the refrigerant gas vaporized by the evaporator 124 through the evaporator 124. The suction valve 7b discharges the high-pressure refrigerant gas compressed in the compression chamber 6 to the condenser 122 through the gas flow path 125. It is a discharge valve.

A cylindrical movable body (bobbin) 8 having a bottom and having a piston 5 side opened is integrally fixed to a support rod 9 of the piston 5 on the piston 5. A piston spring 10, which is a coil spring for elastically supporting the bobbin 8 and the piston 5 reciprocally, is fixed between the center portion of the bottom surface of the housing 1 and the support rod 9. Also,
An annular metal plate 81 is fixed to the surface of the bobbin 8 facing the yoke 2.

The piston 5 and the bobbin 8 are drivingly connected to a linear motor 11 as a drive source for reciprocally driving them. The yoke 2 is formed with an annular recess 12 arranged concentrically with the cylinder fitting hole 3.
An annular permanent magnet 13 is attached to the outer side surface 12a of the second motor 2 with a predetermined gap S between it and the inner side surface 12b.
1 magnetic circuit 14 is configured. This magnetic circuit 14
Thus, a magnetic field having a predetermined strength is generated in the gap S between the magnet 13 and the inner side surface of the recess 12.

The bobbin 8 is arranged so as to be able to reciprocate in the gap S, and an electromagnetic coil 15 is wound around the outer peripheral portion of the bobbin 8 at a position facing the magnet 13 and a lead wire. By passing an alternating current of a predetermined frequency (60 Hz in this embodiment) from the power supply device 17 via 16, the coil 15 and the bobbin 8 are driven by the action of the magnetic field passing through the gap S to move the piston 5 into the cylinder 4. The reciprocating movement is performed so that the gas pressure of a predetermined cycle is generated in the compression chamber 6. The power supply device 17 supplies a predetermined drive current to the electromagnetic coil 15 based on a control command from a control circuit (control means) 18 that controls the drive power.

On the other hand, the surface of the yoke 2 facing the bobbin 8 comes into contact with the bobbin 8 when the piston 5 moves to the top dead center side over the set maximum range, so that the piston 5 and the bobbin 8 move to the bottom dead center of the piston 5. A plurality of metal coil springs 21 (four in the present embodiment are arranged at equal intervals) are provided as electric conductors that apply a biasing force to the point side. A contact detection circuit 22 is provided which forms an electrically closed circuit when the plate 81 contacts and detects the contact of the bobbin 8 with the coil spring 21. Here, the contact detection circuit 22 is connected to the metal plate 81 so that an electrically closed circuit is formed when one of the coil springs 21 contacts the metal plate 81 (Fig. (Not shown). However, an electric closed circuit may be formed when all the coil springs 21 contact the metal plate 81. Then, by the coil spring 21 and the contact detection circuit 22,
Abnormal displacement detection means 23 is configured.

When the contact detection circuit 22 detects the contact of the bobbin 8 with the coil spring 21, the detection signal is supplied to the control circuit 18, and the control circuit 18 supplies the drive current to the electromagnetic coil 15. The command value is set to 0, and the supply of drive power from the power supply device 17 to the electromagnetic coil 15 is stopped.

Thus, when an abnormal displacement of the piston 5 occurs, the drive current supply to the electromagnetic coil 15 is immediately stopped and the displacement force of the piston 5 and the bobbin 8 toward the top dead center of the piston is absorbed. 5 is a valve 7a, 7
The valves 7a and 7b are not destroyed by colliding with b, and the bobbin 8 is not destroyed by colliding with the yoke 2. Further, since the annular metal plate 81 is fixed to the surface of the bobbin 8 facing the yoke 2, the bobbin 8 can be structurally reinforced. Therefore, destruction and failure of the linear compressor are prevented, and the reliability and durability of the device are improved.

The above description of the embodiments is for explaining the present invention, and should not be construed as limiting the invention described in the claims or reducing the scope. Also, the configuration of each part of the present invention is not limited to the above-described embodiment,
It goes without saying that various modifications are possible within the technical scope described in the claims.

For example, in the above description of the embodiment, the case where the electric conductor 21 is composed of the coil spring has been described, but the electric conductor 21 may be composed of the plate spring.

Further, in the control circuit 18, when the abnormal displacement of the piston occurs, the drive current supply to the electromagnetic coil is immediately stopped. However, in addition to this, the drive current is reduced or the reverse current is supplied. It doesn't matter.

Further, although the case where the piston 5 and the bobbin 8 are formed as separate members has been described, they may be formed as the same member, or the permanent magnet 13 may be fixed to the inner side surface of the yoke 2. In addition, the housing 1, the yoke 2, and the cylinder 4 may be constituted by the same body. However, in this case, in order to form the magnetic circuit 13, the magnetic circuit 13 needs to be formed of the same material as the yoke 2.

[0029]

As described above, according to the present invention, when abnormal displacement of the piston occurs, the drive power to the electromagnetic coil is immediately controlled, and the displacement force of the piston and the movable body toward the top dead center of the piston is controlled. Because of the absorption, the piston does not collide with the cylinder to destroy the valve or the like, and the movable body does not collide with the magnetic frame to be destroyed. For this reason, it is possible to prevent the linear compressor from being broken or to fail, and to realize a long life and high reliability of the linear compressor.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a linear compressor showing one embodiment of the present invention.

FIG. 2 is a sectional view of a conventional linear compressor.

FIG. 3 is a conceptual diagram showing the configuration of a closed refrigeration system.

[Explanation of symbols]

 1 Housing 2 Yoke (Magnetic Frame) 3 Cylinder Fitting Hole 4 Cylinder 5 Piston 6 Compression Chamber 7 Valve Mechanism 8 Movable Body (Bobbin) 9 Support Rod 10 Piston Spring 11 Linear Motor 12 Recess 13 Permanent Magnet 14 Magnetic Circuit 15 Electromagnetic Coil 16 Lead wire 17 Power supply device 18 Control circuit (control means) 21 Coil spring (electric conductor) 22 Contact detection circuit 23 Abnormal displacement detection means 81 Metal plate S Gap

Claims (4)

[Claims] 1. A cylinder provided in a housing, a piston fitted in the cylinder so as to reciprocate, and defining a compression chamber in the cylinder, and a bottomed cylinder integrally fixed to the piston at a central portion. -Shaped movable body is arranged in a gap formed in a part of a magnetic circuit composed of a magnet and a magnetic frame, and reciprocates a piston by supplying alternating current of a predetermined frequency to an electromagnetic coil wound around the outer periphery of the movable body. A linear motor for driving, a power supply device that supplies driving power to the electromagnetic coil, a piston spring that elastically supports the piston so that the piston can reciprocate in the cylinder, and the piston is set to the top dead center side. An abnormal displacement detecting means for contacting with the movable body to apply an urging force to the bottom dead center side of the piston and detecting contact with the movable body when the movable body moves beyond the range; Position based on the contact detection signal from the detection means, the linear compressor being characterized in that it and a control means for controlling the supply output of the power supply. 2. The movable body is made of resin, and an annular metal plate is fixed to a contact portion with the abnormal displacement detection means, and the abnormal displacement detection means is in contact with the movable body. An electric conductor that gives an urging force to the bottom dead center side of the piston, and a contact detection that forms an electric closed circuit when the electric conductor contacts the metal plate to detect contact with the movable body. The linear compressor according to claim 1, further comprising a circuit. 3. The control means stops the supply of drive power from the power supply device based on a contact detection signal from the abnormal displacement detection means. Linear compressor. 4. The linear compressor according to claim 2, wherein the electric conductor is a coil spring made of metal.