JP2001248552A - Linear compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain the reliability of a slide part and prevent the lowering of the efficiency of a device by preventing partial contact of a piston with a cylinder even if parallelism between a cylinder shaft axis and a shaft axis is lost. SOLUTION: This linear compressor has the cylinder 6 provided in a housing 1, the piston 7 fitted into the cylinder 6 reciprocatably and partitioning and forming a compression chamber in the cylinder 6, a shaft 12 with one end part connected with the piston 7, and a linear motor 17 reciprocating by driving the piston 7 and the shaft 12 by applying an AC voltage having a predetermined frequency to compress gas in the compression chamber and supply it to the outside. The piston 7 is movably supported in the radial direction orthogonal to the axial direction of the shaft 12 and is oscillatably held around a predetermined section of the shaft 12.

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. 6, a housing 101 having a bottomed cylindrical body, a magnetic frame 102 made of low carbon steel formed at an upper end opening of the housing 101, and a cylinder 103 formed at the center of the magnetic frame 102 When,
Reciprocally fitted in the cylinder 103, the cylinder 10
Piston 105 for forming compression chamber 104 in inner space 3
And a linear motor 106 as a drive source for driving the piston 105 back and forth.

In the linear motor 106, an annular permanent magnet 107 is arranged concentrically outside the cylinder 103 and is fixed to the housing 101. This magnet 10
A magnetic field B is generated in a cylindrical gap 108 concentric with the center of the cylinder 103 by a magnetic circuit including the magnetic frame 7 and the magnetic frame 102. The gap 105 has a piston 105 at the center.
Cylindrical movable body 10 made of resin integrally fixed to
A coil spring 110 for elastically supporting the movable body 109 and the piston 105 so as to reciprocate is fixed to the housing 101.

A magnet 107 is mounted on the outer periphery of the movable body 109.
The electromagnetic coil 111 is wound at a position facing the
By passing an alternating current of a predetermined frequency through a lead wire (not shown), the coil 111 and the movable body 109 are driven by the action of a magnetic field passing through the gap 108, and the piston 10
5 is reciprocated in the cylinder 103 to generate a gas pressure in a predetermined cycle in the compression chamber 104.

On the other hand, a typical refrigeration system is shown in FIG.
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 pipe 125 is known. The refrigerant gas vaporized by the condenser 124 is sucked through a gas flow pipe 125 and compressed to a high pressure, and the high pressure refrigerant gas is discharged to the condenser 122 through the gas flow pipe 125.

For this reason, as shown in FIG.
4 includes a valve mechanism 1 provided at the upper end of the cylinder 103.
12, a gas flow path pipe 12 outside the housing 101.
5 is connected. The valve mechanism 112 is connected to the gas flow pipe 1
The suction valve 112a allows only the suction of the refrigerant gas from the evaporator 124 via the inlet 25, and the discharge valve 112b allows only the discharge of the refrigerant gas to the condenser 122 via the gas flow pipe 125. You. The suction valve 112 a is a valve that causes a gas to flow in the direction of the compression chamber 104 by the pressure difference between the refrigerant gas in the gas passage pipe 125 on the low pressure side and the compression chamber 104. The discharge valve 112b is opened by the pressure difference of the refrigerant gas between the compression chamber 104 and the gas passage pipe 125 on the high pressure side so that the discharge valve 112b opens when the refrigerant gas pressure in the compression chamber 104 becomes equal to or higher than a predetermined pressure. This is a valve that allows gas to flow out in the direction of the gas flow pipe 125. The suction valve 112a and the discharge valve 112b are both valves that are biased by leaf springs.

With the above arrangement, in the conventional apparatus, the suction valve 1
After the refrigerant gas sucked from 12a is compressed to a high pressure in the compression chamber 104, it is supplied to the condenser 122 via the discharge valve 112b.

Then, the conventional linear compressor 121
In the case where the axis of the cylinder 103 and the axis of the piston 105 are misaligned, the reliability of the piston 105 is reduced due to abrasion of the sliding portion due to the one-side contact of the cylinder 105,
There was a possibility that the efficiency of the compressor was reduced due to an increase in the sliding loss.

For this reason, as shown in FIG. 8, a configuration has recently been proposed in which the piston 105 is connected to and supported on a shaft so that the piston 105 can be slightly moved in a radial direction perpendicular to the axial direction of the piston. Accordingly, even when the axis of the cylinder 103 and the axis of the shaft are misaligned, it is possible to prevent the piston 105 from colliding with the cylinder 103.

[0010]

However, since the piston and the shaft are supported by elastic members such as a coil spring and a suspension spring, the axis of the cylinder and the shaft lose parallelism during the reciprocating motion of the piston. In some cases, the shaft axis has some inclination with respect to the cylinder axis.

[0011] In such a case, the conventional configuration described above cannot cope with the situation, and the piston still hits the cylinder.

The present invention has been made in view of the above point, and even when the parallelism between the cylinder axis and the shaft axis is lost, the piston prevents the cylinder from coming into contact with the cylinder and slides. An object of the present invention is to provide a linear compressor that maintains the reliability of a moving part and prevents a decrease in device efficiency.

[0013]

SUMMARY OF THE INVENTION The present invention provides a cylinder provided in a housing, a piston reciprocally fitted in the cylinder and defining a compression chamber in the cylinder, and one end of which is formed by the piston. A linear motor that applies an alternating voltage of a predetermined frequency to reciprocately drive the piston and the shaft, wherein the linear compressor compresses gas in a compression chamber and supplies the gas to the outside. It is configured to have a predetermined gap with respect to the side wall of the concave portion opened at the shaft side end of the
A joint member provided with a convex portion for contacting the concave portion, an elastic member having one end contacting and pressing and urging the joint member, and another end portion of the elastic member fixed to the piston; And a support member for supporting the projection, the projection of the joint member is always in contact with the recess, the piston can be moved relative to the shaft by a predetermined amount in the radial direction of the axis thereof, and It is characterized in that it is held so as to be able to swing around the contact point of the projection. More specifically, the joint member includes a protruding portion provided at a base end of the projection so as to have a predetermined gap with respect to a side wall of the recess.

By using this configuration, even when the shaft is shaken with respect to the cylinder and the parallelism between the cylinder axis and the shaft axis is lost, the shaft shake between the cylinder and the piston is prevented. This can be prevented from occurring.

Further, since the other end of the elastic member which presses and biases the joint member is supported by the support member, the connection state between the piston and the joint member is maintained even if the elastic member is damaged. And operation can be continued.

The projection may have a hemispherical tip, and the projection may be a disk-shaped projection having an outer diameter smaller than the inner diameter of the recess. By using this configuration, the convex portion of the joint member is
The piston comes into contact with the concave portion of the piston in a point contact state, and the piston is held so as to be rotatable around the contact point with the convex portion.

Further, the elastic member is constituted by a leaf spring member having a cylindrical C-shaped cross section.

[0018]

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.

As shown in FIG. 7, the linear compressor of the present invention is used as a compressor of a closed type refrigeration system. As a linear compressor, as shown in FIG.
And holds the linear compressor as an enclosed space. The housing 1 has compression chambers 2 and 3 at its upper and lower parts.

A magnetic frame (yoke) 4 made of low carbon steel is formed at a lower portion of the housing 1.
A cylinder fitting hole 5 extending in the vertical direction is formed through a central portion of the cylinder, and a bottomed cylindrical first cylinder 6 made of stainless steel is fitted into the cylinder fitting hole 5.

In the first cylinder 6, a first piston 7 is slidably fitted, and the first cylinder 6 and the first piston 7 define an upper compression chamber 2 serving as a compression space for refrigerant gas. Is done. The first cylinder 6 is provided with a first suction valve 8a connected to an external gas flow path pipe 125 for sucking the refrigerant gas vaporized by the evaporator 124.

On the other hand, a second cylinder 9 extending in the vertical direction is provided at a lower portion of the housing 1 on the side opposite to the first cylinder 6, and a second piston 10 is slidable in the second cylinder 9. And a lower compression chamber 3 serving as a compression space for the refrigerant gas is defined by the second cylinder 9 and the second piston 10. Similarly to the upper compression chamber 2, the second cylinder 9 is provided with a second suction valve 11a connected to an external gas flow path pipe 125 for sucking the refrigerant gas vaporized by the evaporator 124. .

The first piston 7 and the second piston 10 are connected to both ends of a piston shaft 12, respectively, and have a bottomed cylindrical movable body (bobbin with the first piston 7 side opened to the piston shaft 12). ) 13 are integrally fixed.

An annular recess 15 is formed in the yoke 4 so as to be concentric with the cylinder fitting hole 5. An annular permanent magnet 16 is provided between the outer side surface 15a of the recess 15 and the inner side surface. The magnet 16 and the yoke 4 constitute a magnetic circuit 18 of a linear motor 17. The magnetic circuit 18 provides a gap between the magnet 16 and the inner side surface of the recess 15 with a predetermined strength. A magnetic field is generated. The bobbin 13 is disposed in a gap formed in a part of a magnetic circuit 18 including the magnet 16 and the yoke 4, and an alternating current of a predetermined frequency is supplied to an electromagnetic coil 19 wound around the outer periphery of the bobbin 13 by a power supply device (see FIG. (Not shown), the first piston 7 and the second piston 10 are reciprocated in the first cylinder 6 and the second cylinder 9 respectively, and the gas pressure of a predetermined cycle is generated in the upper compression chamber 2 and the lower compression chamber 3. Has been made to occur. The power supply supplies a predetermined drive current to the electromagnetic coil 19 based on a control command from a control unit (not shown) for controlling the drive power.

As shown in FIG. 2, the first piston 7 is provided with a concave portion 7a having an opening on the piston shaft 12 side, and a joint member 21 having a convex portion 21a provided at the distal end portion in contact with the concave portion 7a. Are integrally attached to the first piston side end of the piston shaft 12.

The projecting portion 21a of the joint member 21 has a hemispherical tip at the tip, and comes into contact with the recessed portion 7a in a point contact state. The joint member 21 has an outer diameter (d1) smaller than the inner diameter (d1) of the recess 7a.
2) is provided at the base end of the projection 21a, and the side wall of the recess 7a and the disk-shaped projection 21b are provided.
And a predetermined clearance (about 5 in the present embodiment).
0 μm).

A leaf spring (one end of which is in contact with the disc-shaped projecting portion 21b so that the projection 21a of the joint member 21 always contacts the recess 7a of the first piston 7 in a point contact state). (Member 22). The other end of the leaf spring 22 is supported by a support member 23 fixed to the first piston 7.

Here, the leaf spring 22 is, as shown in FIG.
It is constituted by a "flat spring" having a tubular cross-section having a C-shape having an opening 22a through which the joint member 21 penetrates. Here, FIG. 4 is an explanatory view for explaining the shape of the spring 22. FIG. 4 (a) is a perspective view, and FIG. 4 (b) is a top view and a side sectional view. Note that, as the leaf spring 22, FIG.
A leaf spring having a shape as shown in FIG. here,
FIG. 5 shows a top view and a side sectional view of a leaf spring 22 having another configuration.

The support member 23 has an opening through which the joint member 21 is inserted. As will be described later, the first piston 7 can be moved in the radial direction of the axis within the range of the clearance. In addition, the dimensions of the opening are set so as to be rotatable around the contact point of the projection 21a.

The leaf spring 22 is connected to the joint member 2.
Since only a force acts in a direction of pressing the first piston 7 toward the first piston 7, the first piston 7 is connected to the joint member 21 so as to be movable in the radial direction of the axis within the clearance. ing.

The distal end of the convex portion 21a of the joint member 21 has a hemispherical shape and is brought into contact with the concave portion 7a of the first piston 7 in a point contact state by the leaf spring 22. If the axis and the axis of the first cylinder 6 lose parallelism and the axis of the piston shaft 12 is inclined with respect to the first cylinder 6, the first
The piston 7 rotates around the contact point with respect to the joint member 21 so that the axis of the first piston 7 is
Is parallel to the axis of.

As a result, the piston shaft 12 is
Even if shaft runout occurs with respect to cylinder 6, shaft runout between first cylinder 6 and first piston 7 is prevented from occurring,
The reliability of the sliding portion can be maintained without the first piston 7 colliding with the first cylinder 6, and a decrease in efficiency due to wear of the sliding portion can be prevented. In particular, when the first piston 7 and the second piston 10 are connected to both sides of the piston shaft 12 as in the present embodiment, the distance between the piston shaft 12 and the first cylinder 6 or the second cylinder 9 is increased. In this case, the shaft is easily shaken, and the effect can be particularly expected.

In the above description, only the structure of the connection between the first piston 7 and the piston shaft 12 has been described in detail.
Similarly to the first piston 7, the second piston 10
a is provided. Then, the projection 24a of the joint member 24 integrally attached to the piston shaft 12
The second piston 10 is connected to the piston shaft 12 via the joint member 24 by being pressed and urged by the plate spring 25 so as to always contact the concave portion 10a in a point contact state. Here, the second piston 10 and the joint member 2
Since the configuration of the connecting portion 4 is the same as that of the first piston 7 and the joint member 21, detailed description thereof is omitted.

The description of the above embodiment is for the purpose of explaining the present invention, and should not be construed as limiting the invention described in the claims or reducing the scope thereof. 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 embodiment, a two-piston configuration has been described. However, the present invention can be applied to a one-piston linear compressor.

Further, the case where the leaf spring 22 such as a flat spring is used as the elastic member has been described. However, the present invention is not limited to this, and a coil spring may be used. However, in this case, in order to obtain the required spring constant, increase the wire diameter,
There is a possibility that the number of turns must be increased, and the axial dimension of the concave portion 7a of the piston 7 must be longer than that of the case of the leaf spring 22.

[0037]

As described above, according to the present invention, even when the shaft is deflected with respect to the cylinder and the parallelism between the cylinder axis and the shaft axis is lost, the cylinder and the piston can be moved. Can be prevented from occurring.

Therefore, the reliability of the sliding portion can be maintained without the piston coming into contact with the cylinder, and a decrease in efficiency due to wear of the sliding portion can be prevented.

[Brief description of the drawings]

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

FIG. 2 is a cross-sectional view of a main part for describing a configuration of a first piston 7 and a joint member 21 in the apparatus of FIG.

FIG. 3 is a cross-sectional view of a main part for describing an operation of a first piston 7 in the apparatus in FIG.

FIG. 4 is an explanatory diagram illustrating a configuration of a leaf spring 22 in the apparatus of FIG.

FIG. 5 is an explanatory diagram illustrating another configuration of the leaf spring 22 in the apparatus of FIG. 1;

FIG. 6 is a sectional view of a conventional linear compressor.

FIG. 7 is a conceptual diagram showing a configuration of a closed type refrigeration system.

FIG. 8 is a cross-sectional view illustrating a connection portion between a conventional improved piston and a shaft.

FIG. 9 is a cross-sectional view of a main part for describing an operation of a piston 105 in the device in FIG. 8;

[Explanation of symbols]

 Reference Signs List 1 housing 2 upper compression chamber 3 lower compression chamber 6 first cylinder 7 first piston 7a, 10a recess 8 first valve mechanism 9 second cylinder 10 second piston 11 second valve mechanism 12 piston shaft 13 movable body (bobbin) 19 Electromagnetic coils 21, 24 Joint members 22, 25 Leaf springs (elastic members) 23, 26 Support members 21a, 24a Protrusions 21b, 24b Disc-shaped protrusions

Claims (4)

[Claims] A cylinder provided in a housing;
A piston reciprocally fitted in the cylinder and defining a compression chamber in the cylinder, a shaft having one end connected to the piston, and an AC voltage of a predetermined frequency applied to reciprocate the piston and the shaft. A linear motor to be driven, wherein the linear compressor compresses gas in the compression chamber and supplies the gas to the outside, wherein the piston has a predetermined gap with respect to a side wall of a concave portion formed at a shaft side end of the piston. A joint member provided with a convex portion for contacting the concave portion, an elastic member having one end contacting and pressing the joint member, and the elastic member fixed to the piston. And a support member for supporting the other end of the joint member, and the projection of the joint member is always in contact with the recess, and the piston is moved with respect to the shaft. Its radial axis in a predetermined amount movable, and a linear compressor, characterized in that it is swingably held around the abutting points of the convex portion. 2. The joint member according to claim 1, further comprising: a protruding portion provided at a base end of the convex portion so as to have a predetermined gap with respect to a side wall of the concave portion. The described linear compressor. 3. The method according to claim 3, wherein the projecting portion has a tip portion having a hemispherical shape, and the projecting portion is a disc-shaped projecting portion having an outer diameter smaller than an inner diameter of the recess. 3. The linear compressor according to claim 2, wherein: 4. The linear compressor according to claim 1, wherein said elastic member is formed of a leaf spring member having a cylindrical cross-section having a C-shape.