KR20130026878A - Reciprocating compressor - Google Patents

Abstract

PURPOSE: A reciprocating compressor is provided to coat a porous layer having plural micro-pores on at least one of the bearing surfaces of a cylinder and a piston, thereby easily machining the bearing surface equipped in a gas bearing, and properly controlling the dispersion of the micro-pores. CONSTITUTION: A reciprocating compressor includes a sealed casing, a cylinder(41), a piston, and a gas bearing. The cylinder equipped with a compression space is equipped inside the casing. The piston is inserted into the compression space of the cylinder so that the piston is capable of relatively reciprocating. The gas bearing lubricates the bearing surfaces of the cylinder and the piston with a gas. A porous layer having plural micro-pores is coated on at least one of the bearing surfaces of the cylinder and the piston.

Description

Reciprocating Compressor {RECIPROCATING COMPRESSOR}

The present invention relates to a reciprocating compressor, and more particularly to a reciprocating compressor having a gas bearing.

Generally, a reciprocating compressor is a system in which a piston linearly reciprocates in a cylinder and sucks and compresses a refrigerant to discharge the refrigerant. The reciprocating compressor can be classified into a connection type and a vibration type according to the driving method of the piston.

In the connection type reciprocating compressor, the piston is connected to the rotating shaft of the rotating motor by a connecting rod, and the refrigerant is compressed while reciprocating in the cylinder. On the other hand, a vibrating reciprocating compressor is a system in which a piston is connected to a mover of a reciprocating motor and reciprocates in a cylinder while vibrating to compress a refrigerant. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibrating reciprocating compressor. In the following description, the vibrating reciprocating compressor is abbreviated as a reciprocating compressor.

The reciprocating compressor may be lubricated smoothly in a tightly sealed state between the cylinder and the piston to improve the compressor performance. To this end, in the related art, a method of sealing and simultaneously lubricating between a cylinder and a piston by forming an oil film by supplying a lubricant such as oil between the cylinder and the piston is widely known. However, in the method of supplying lubricant, not only a separate oil supply device is required, but also a lack of oil may occur depending on operating conditions, thereby degrading compressor performance. In addition, since a space for accommodating a certain amount of oil is required, the size of the compressor is increased, and the inlet of the oil supply device must always be immersed in oil, so the installation direction of the compressor has to be limited.

In view of the drawbacks of the oil-lubricated reciprocating compressor as described above, as shown in FIG. 1, a portion of the compressed gas is bypassed between the piston 1 and the cylinder 2 so as to bypass the piston 1. Techniques are known for forming gas bearings between the cylinders 2. This is to form a plurality of gas passages 2a having a small diameter in the cylinder 2 or to form a sintered porous material member (not shown) having a porous shape on the inner circumferential surface of the cylinder 2. I install it. This technology does not require a separate oil supply device compared to the oil lubrication method for supplying oil between the piston (1) and the cylinder (2), which not only simplifies the lubrication structure of the compressor, but also lacks oil according to operating conditions. This prevents the compressor's performance from being consistent. In addition, since the space for accommodating the oil is not required in the casing of the compressor, the compressor can be miniaturized and the installation direction of the compressor can be freely designed.

On the other hand, when the gas bearing is applied to the reciprocating compressor, the leaf spring 3 is applied for the resonance movement of the piston as shown in FIG.

When the leaf spring 3 is applied as described above, the piston 1 forming the compression section 4 has a straightness in the cylinder (shown in FIG. 1) 2. And leaf springs (shown in FIG. 2) 3 by a flexible connecting bar (not shown), or by dividing the connecting bars 5a-5c into a plurality of at least one (preferably). Is connected by two or more links 6a to 6b.

However, in the conventional reciprocating compressor as described above, when the gas passage having a small diameter is formed in the cylinder, the gas passage is not only difficult to form as a micro hole, but also a foreign gas such as fine powder generated during operation of the compressor is fine. Clogging the flow path prevents the gas force from acting uniformly in the circumferential direction of the piston, which causes partial friction between the cylinder and the piston, thereby degrading the performance and reliability of the compressor, thereby requiring very high cleanliness.

In addition, in the case of inserting the porous member sintered in a porous shape into the inner circumferential surface of the cylinder, not only the manufacturing cost of the porous member is high, but also the abrasion resistance is low, and wear occurs in the porous member at initial startup before the gas bearing is formed. Life may be reduced. In addition, it is difficult to properly control the dispersion of the hole due to the characteristics of the porous member has a problem that it is difficult to design the gas bearing to be lubricated while properly sealing between the cylinder and the piston.

In addition, when the outlet of the gas flow path is formed in the cylinder, when the piston performs the suction stroke, the outlet of the gas flow path is exposed to the compression space, so that a high pressure refrigerant flows into the compression space while suction loss occurs. When the inlet of the gas flow path is formed in the piston, the inlet of the gas flow path is exposed to the compression space during the suction stroke of the piston, so that the gas of the gas bearing flows back into the compression space.

It is an object of the present invention to provide a reciprocating compressor which is easy to process into a gas flow path for guiding compressed gas to a gas bearing.

In addition, another object of the present invention, by forming a porous layer on the cylinder or the piston without fabricating and assembling a separate porous member, the reciprocating compressor can be easily manufactured while increasing the wear resistance and can properly control the distribution of micropores I'm trying to provide.

In addition, the outlet of the gas passage is formed in the piston while the outlet of the gas passage is formed in the cylinder, thereby preventing the inlet or outlet of the gas passage from communicating with the compression space during the suction stroke of the piston, thereby improving the compressor performance. It is to provide a dynamic compressor.

In order to achieve the object of the present invention, a sealed casing; A cylinder provided in the inner space of the casing and having a compression space; A piston inserted to allow relative reciprocation in the compression space of the cylinder; And a gas bearing for lubricating the bearing surfaces of the cylinder and the piston with gas, wherein the gas bearing is coated with a porous layer having a plurality of micropores on at least one of the bearing surfaces of the cylinder and the piston. There is provided a reciprocating compressor that is formed.

In the reciprocating compressor according to the present invention, a porous layer having a plurality of micro-pores is coated on at least one of the bearing surfaces of the cylinder and the piston, so that the bearing surface of the gas bearing can be easily processed and wear resistant. It can increase and the dispersion of micropores can be adjusted appropriately.

In addition, the gas flow path for guiding the compressed gas to the gas bearing can be easily processed.

In addition, while the outlet of the gas passage is formed in the piston, the inlet of the gas passage is formed in the cylinder, thereby preventing the inlet or outlet of the gas passage from communicating with the compression space during the suction stroke of the piston.

1 is a longitudinal sectional view showing an example in which a conventional gas bearing is applied to a reciprocating compressor;
Figure 2 is a perspective view showing an example applied to a conventional leaf spring reciprocating compressor,
Figure 3 is a longitudinal sectional view showing the present invention reciprocating compressor,
4 is an exploded perspective view of the reciprocating motor in the reciprocating compressor according to FIG. 3;
5 is a half sectional view showing an example of a stator in the reciprocating motor according to FIG. 3;
Figure 6 is a half sectional view showing another embodiment of the stator in the reciprocating motor according to Figure 3,
7 is a cross-sectional view showing an embodiment of a gas bearing in the reciprocating compressor according to FIG.
FIG. 8 is a sectional view taken along the line “II” of FIG. 7;
FIG. 9 is a sectional view taken along the line “II-II” of FIG. 7;
10 is an enlarged cross-sectional view of a portion “A” at 7;
FIG. 11 is a partial cross-sectional view illustrating a resonance spring in the reciprocating compressor according to FIG. 3;
12 is a front view shown to explain the arrangement of the resonant spring according to FIG.

Hereinafter, the reciprocating compressor according to the present invention will be described in detail based on the embodiment shown in the accompanying drawings.

As shown in FIG. 3, in the reciprocating compressor according to the present embodiment, a frame 20 is installed in a sealed casing 10, and the reciprocating motor 30 and the cylinder 41 are installed in the frame 20. ) Is fixed to the cylinder 41 is coupled to the piston 42 coupled to the mover 32 of the reciprocating motor 30 to reciprocate, the piston 42 on both sides of the movement direction of the piston 42 Resonant springs 51 and 52 for inducing the resonant motion of 42 are respectively provided.

A compression space S1 is formed in the cylinder 41 and a suction channel F is formed in the piston 42. A sucking channel F for opening and closing the suction channel F is formed at the end of the suction channel F, A valve 43 is provided and a discharge valve 44 for opening and closing the compression space S1 of the cylinder 41 is provided on the end surface of the cylinder 41. [

In the reciprocating compressor according to the present embodiment, when power is applied to the coil 35 of the reciprocating motor 30, the motor 32 of the reciprocating motor 30 reciprocates. Then, the piston 42 coupled to the muffler 32 linearly reciprocates in the cylinder 41, sucks the refrigerant, compresses the refrigerant, and discharges the compressed refrigerant.

In detail, when the piston 42 is retracted, the refrigerant of the closed vessel 10 is sucked into the compression space S1 through the suction passage F of the piston 42, and when the piston 42 moves forward The suction passage (F) is closed and the refrigerant in the compression space (S1) is compressed. When the piston 42 further advances, the refrigerant compressed in the compression space S1 is discharged while opening the discharge valve 44 and is moved to the external refrigeration cycle.

4 and 5, the reciprocating motor 30 includes a stator 31 having a coil 35 and an air gap only on one side of the coil 35, and of the stator 31. Inserted into the gap and provided with a magnet 325 is made of a mover 32 for linear movement in the movement direction.

The stator 31 includes a plurality of stator blocks 311 and a plurality of pole blocks 315 that are coupled to one side of the stator block 311 and form air gap portions 31a together with the respective stator blocks 311. [ ).

The stator block 311 and the pole block 315 are formed by stacking a plurality of thin stator cores in the form of an arc when projected in the axial direction.

The stator block 311 is formed in a groove shape when projected in the axial direction, and the pole block 315 is formed in a rectangular shape in the axial direction projection.

The stator core 311 includes a first magnetic path portion 312 which is positioned inside the mover 32 with respect to the mover 32 and forms an inner stator, And a second magnetic path portion 311 that is integrally formed at one axial end of the first magnetic path portion 312, that is, at the opposite end of the gap 31a, 313).

The first magnetic path portion 312 is formed in a stepped shape while the second magnetic path portion 313 is formed in a rectangular shape so that the first magnetic path portion 312 is formed on the inner circumferential side surface of the first magnetic path portion 312, As shown in Fig.

The groove formed in the inner wall surface of the first magnetic path portion 312 and the second magnetic path portion 313 is formed with a coil receiving groove 31b which is open at one axial side, that is, toward the air gap, The pole block 315 is engaged with the axial end face of the first magnetic path portion 312 constituting the coil accommodating groove 31b to cover the axial opening face of the coil receiving groove 31b.

The coupling surface 311a of the stator block 311 and the coupling surface 315a of the pole block 315 that connect the stator block 311 and the pole block 315 to form a magnetic connection portion (not shown) An engaging groove 311b and an engaging projection 315b may be formed to firmly couple the stator block 311 and the pole block 315 and maintain a constant curvature. Not shown, but may be stepped-coupled.

The coupling surface 311a of the stator block 311 and the coupling surface 315a of the pole block 315 are formed to be planar except for the coupling groove 311a and the coupling protrusion 315a, It is possible to prevent a clearance from being generated between the stator block 311 and the pole block 315 and prevent leakage of the magnetic flux between the stator block 311 and the pole block 315, .

A first pole portion 311c having a larger cross sectional area is formed at an end of the second magnetic path portion 313 of the stator block 311 or an end portion of the gap portion 31a, A second pole portion 315c having a larger cross-sectional area is formed at the end of the pole block 315 corresponding to the pole block 311c.

The mover 32 includes a magnet holder 321 formed in a cylindrical shape and a plurality of magnets 325 coupled to the outer circumferential surface of the magnet holder 321 in the circumferential direction to form a magnetic flux together with the coil 35. [ .

The magnet holder 321 is preferably formed of a non-magnetic material to prevent leakage of magnetic flux, but it is not necessarily limited to a non-magnetic material. The outer circumferential surface of the magnet holder 321 is formed in a circular shape so that the magnet 325 can be linearly contacted. A magnet mounting groove (not shown) may be formed on the outer circumferential surface of the magnet holder 321 such that the magnet 325 is inserted and supported in a moving direction.

The magnet 325 may have a hexahedral shape and may be attached to the outer circumferential surface of the magnet holder 321 one by one. When the magnets 325 are attached one by one, the outer circumferential surface of the magnet 325 may be wrapped with a supporting member (not shown) such as a separate fixed ring or a tape made of a composite material.

The magnet 325 may be attached to the outer circumferential surface of the magnet holder 321 along the circumferential direction of the magnet holder 321. The stator 31 may include a plurality of stator blocks 311, The magnet 325 is also attached to the outer circumferential surface of the magnet holder 321 at a predetermined interval along the circumferential direction, that is, with a gap between the stator blocks, so that the amount of magnet used is minimized It is preferable. In this case, it is preferable that the magnet 325 is formed to have a length corresponding to the gap length of each stator holder 321, that is, the circumferential length of the gap.

The magnet 325 is formed to be larger than the moving direction length of the air gap 31a so as to be precisely larger than the moving direction length of the air gap 31a, It is preferable that one end of the hollow portion 31a is located inside the hollow portion 31a for a stable reciprocating motion.

The magnets 325 may be disposed one by one in the moving direction, but may be arranged in plural along the moving direction. The magnet may be arranged so that the N pole and the S pole correspond to each other along the movement direction.

The reciprocating motor as described above may be formed such that the stator has one air gap 314 as shown in FIG. 5, but in some cases, the air gaps 31a are formed at both sides of the coil in the reciprocating direction as shown in FIG. 6. It may be formed to have a (31c). In this case, the mover 32 may be formed in the same manner as in the above-described embodiment.

On the other hand, in the above-described reciprocating compressor, the friction loss between the cylinder and the piston must be reduced to improve the performance of the compressor. To this end, conventionally, a gas bearing is known in which a part of the compressed gas is bypassed between the inner circumferential surface of the cylinder and the outer circumferential surface of the piston to lubricate the cylinder and the piston with gas force. In this case, a gas passage having a small diameter may be formed in the cylinder, or a porous member sintered and formed in a porous shape on the inner circumferential surface of the cylinder.

However, as described above, when the gas flow path having a small diameter is formed in the cylinder, it is difficult not only to form the gas flow path into fine pores, but also foreign matters such as fine powder generated during the operation of the compressor block the fine gas flow path. Force could not act uniformly in the circumferential direction of the piston.

In addition, in the case of inserting the porous member sintered in a porous shape into the inner circumferential surface of the cylinder, not only the manufacturing cost of the porous member is high, but also the abrasion resistance is low, and wear occurs in the porous member at initial startup before the gas bearing is formed. Life may be reduced. In addition, due to the nature of the porous member it is difficult to properly control the distribution of the hole may be difficult to design the gas bearing so that the lubrication can be properly sealed between the cylinder and the piston.

In addition, when the outlet of the gas flow path is formed in the cylinder, when the piston performs the suction stroke, the outlet of the gas flow path is exposed to the compression space, so that a high pressure refrigerant flows into the compression space while suction loss occurs. When the inlet of the gas flow path is formed in the piston, the inlet of the gas flow path may be exposed to the compression space during the suction stroke of the piston, so that the gas of the gas bearing may flow back into the compression space.

The gas bearing according to the embodiments of the present invention provides a high-pressure compressed gas by forming an oxide film layer on the inner circumferential surface of the cylinder or on the outer circumferential surface of the piston, which has a plurality of micropores and relatively easy to control the dispersion of the micropores. To distribute evenly between the cylinder and the piston.

As shown in FIG. 7, the oxide film layer 412 may be formed to have a plurality of micro-pores 412a on the inner circumferential surface of the cylinder body 411 (or may be formed on the outer circumferential surface of the piston body). In this case, the compressed gas guided to the micro-pores 412a through the gas passage 401 is evenly supplied between the cylinder 41 and the piston 42 through the micro-pores 412a to form a gas bearing. Done.

The anodization layer 412 may be formed by anodizing or microarray coating (MAO).

Here, the gas flow passage 401 may be formed in the cylinder body 411 as shown in Figs. The gas flow passage 401 includes at least one first flow passage 401a formed in the reciprocating direction of the piston 42 at the discharge end surface 411a of the cylinder body 411 accommodated in the discharge cover 46; It consists of a plurality of second flow path (401b) penetrating toward the inner peripheral surface of the cylinder body 411 in the middle of the first flow path (401a). The distal end surface 411a of the cylinder body 411 protrudes by a predetermined height to form a protrusion 411b and the discharge cover 46 is inserted and coupled to the outer circumferential surface of the protrusion 411b.

The start end of the first flow path 401a, that is, the inlet end of the first flow path 401a in contact with the discharge space S2, is discharge valve 45 selectively detachable from the front end surface 411a of the cylinder body 411. It is preferably formed farther than the radius (Ds) of the discharge valve 45 with respect to the center of the discharge valve 45 to be located outside the detachable range of the).

The diameter of the second flow path 401b may be formed within a range of 1/10 to 1 compared to the diameter of the first flow path 401a, but the end of the second flow path 401b may be in contact with the oxide film layer 412. Therefore, it may be formed to the same diameter as the first flow path (401a) or slightly larger.

In addition, an annular filter 47 may be installed at the front end side of the first flow path 401 a, that is, the front end surface 411 a of the cylinder body 411 to prevent foreign matter from flowing into the gas flow path 401. Can be.

At least one gas diffusion groove (not shown) may be further formed on the outer circumferential surface of the piston 42, but as the oxide film layer 412 is formed in a porous shape as shown in FIG. Even if the gas diffusion groove is not formed on the outer circumferential surface, the compressed gas of high pressure can be uniformly distributed to the bearing region between the cylinder 41 and the piston 42.

In the case of forming the porous layer with the oxide film layer as described above, not only the porous layer can be easily formed on the inner circumferential surface of the cylinder body but also the strength of the bearing surface made of the oxide film layer is increased to have high wear resistance and frictional resistance The reliability of the compressor can be improved.

In addition, when the gas inlet hole is formed in the piston 42, the gas inlet hole must communicate with the compression space. Therefore, when the piston performs the suction stroke, the refrigerant sucked into the compression space does not leak into the gas inlet hole. Since the check valve must be installed, the manufacturing cost may increase accordingly, but as the gas inlet hole is formed in the cylinder side as in the present embodiment, it is easy to process and lower the manufacturing cost.

On the other hand, the reciprocating compressor equipped with the gas bearing as described above can change the installation form of the compressor without using a leaf spring, and at the same time eliminate the use of a separate connecting bar or link to reduce material costs and assembly labor Coil spring is applied to the resonant spring.

In this embodiment, in the reciprocating compressor provided with the gas bearing as described above, the installation form of the compressor is variously changed without using a leaf spring, and at the same time, the use of a separate connecting bar or link is eliminated, thereby reducing material cost and assembly labor. The coil spring is applied to the resonant spring so that it can be.

As shown in FIG. 11, the resonant springs include first and second resonant springs 51 and second resonant springs respectively installed at both front and rear sides of the spring supporter 53 coupled to the mover 32 and the piston 42. 52).

The first resonance spring 51 and the second resonance spring 52 are each provided in plural numbers and are arranged along the circumferential direction. However, only one of the resonant springs of the first resonant spring 51 and the second resonant spring 52 may be provided in plurality, and only one of the other resonant springs may be provided.

As the first resonant spring 51 and the second resonant spring 52 are made of a compressed coil spring as described above, side forces are generated when the resonant springs 51 and 52 are stretched. Can be. Accordingly, the resonant springs 51 and 52 may be arranged to cancel side forces or torsion moments of the resonant springs 51 and 52.

For example, when the first resonance springs 51 and the second resonance springs 52 are alternately arranged in the circumferential direction as shown in FIG. 12, the first resonance springs 51 and the second resonance springs are alternately arranged. (52) is wound at the same position when the end is relative to the center of the piston 42, all the counterclockwise winding, while the same resonant springs located in each diagonal direction between the side force and torsion in opposite directions The moments can be arranged symmetrically to each other so that they can be generated.

The first resonant spring 51 and the second resonant spring 52 may be arranged by symmetrically matching the end points of the resonant springs so that side forces and torsion moments may be generated in opposite directions along the circumferential direction. have.

Here, the spring fixing protrusions may be pressed into the frame or the spring supporter 53 to which the ends of the first resonance spring 51 and the second resonance spring 52 are fixed so as to be press-fitted and fixed. It is preferable that the 531 and 532 are formed, respectively, to prevent rotation of the fitted resonant spring.

The first resonant spring 51 and the second resonant spring 52 may be provided in the same number, or may be provided in different numbers. However, the first resonance spring 51 and the second resonance spring 52 may be provided to have the same elastic force, respectively.

When the resonant springs 51 and 52 made of the compressed coil springs are applied as described above, the side force may be generated in the process of expansion and contraction due to the characteristics of the compressed coil springs, but the straightness of the piston 42 may be deteriorated. As the plurality of first resonant springs 51 and the second resonant springs 52 are arranged so as to be wound in opposite directions, the side forces and the torsion moments generated at the respective resonant springs 51 and 52 are diagonal. By canceling by the resonant spring symmetric in the direction can not only maintain the straightness of the piston 42, but also prevent the wear of the surface in contact with the resonant springs (51) 52 in advance.

In addition, by applying a compression coil spring having a small longitudinal deformation to the resonant springs 51 and 52, the compressor can be installed not only horizontally but also in a vertical shape, and a separate connecting bar or link is not required. Reduced man-hours

On the other hand, in the above-described embodiments, even when the cylinder is inserted into the stator of the reciprocating motor, or the reciprocating motor is mechanically coupled to the compression unit including the cylinder at a predetermined interval, such a resonance spring is equally applicable. Can be. Detailed description thereof will be omitted.

In addition, in the above-described embodiments, the piston is configured to reciprocate so that the resonant springs are respectively installed on both sides of the piston in the direction of movement, but in some cases, the cylinder is configured to reciprocate so that both sides of the cylinder The resonant spring may be installed in the. Even in this case, the resonant spring may be composed of a plurality of compression coil springs as in the above-described embodiments, and the plurality of compression coil springs may be arranged as in the above-described embodiments. A detailed description thereof will be omitted.

30: reciprocating motor 31: stator
31a: cavity portion 31b: coil receiving groove
311: stator block 312: first magnetic path portion (inner stator)
313: second magnetic pole portion (outer stator) 315: pole block
311c, 315c: pole portion 32:
321: Magnet holder 325: Magnet
41: cylinder 401: gas flow path
401a: first flow path 401b: second flow path
411: cylinder body 411a: front end surface
411b: protrusion 402: cylinder gas path
412: Anodizing layer 42: Piston
43: Suction valve 44: Discharge valve
51,52: resonant spring 53: spring supporter

Claims (6)

Sealed casing;
A cylinder provided in the inner space of the casing and having a compression space;
A piston inserted to allow relative reciprocation in the compression space of the cylinder; And
Includes; a gas bearing for lubricating the bearing surface of the cylinder and the piston with gas, wherein the gas bearing,
And a porous layer having a plurality of micro-pores coated on at least one of the bearing surfaces of the cylinder and the piston. The method of claim 1,
The porous layer is a reciprocating compressor is formed of an oxide film. The method of claim 1,
A discharge valve provided at a front end side of the cylinder to open and close the compression space; And
And a discharge cover provided at a distal end side of the cylinder, the discharge space being provided to be selectively communicated by the discharge valve.
The porous layer is formed on the bearing surface of the cylinder, and at least one gas passage from the front end surface of the cylinder to the porous layer so as to guide the refrigerant in the discharge space to the porous layer. According to claim 3, The gas flow path,
A first flow path formed in the reciprocating direction of the piston at the front end surface of the cylinder, and a second flow path formed at a predetermined angle in the reciprocating direction so as to communicate with the porous layer in the first flow path,
The diameter of the second flow path to the diameter of the first flow path is a reciprocating compressor is formed in the range of 1/5 ~ 1. The method of claim 3,
The inlet of the gas flow passage in contact with the discharge space is formed so as to be located farther than the radius of the discharge valve with respect to the center of the discharge valve. 6. The method according to any one of claims 1 to 5,
A frame is supported inside the casing, and a reciprocating motor for reciprocating the mover is fixed to the frame, and the mover is elastically supported by the resonance spring.
The resonant spring is composed of a compression coil spring reciprocating compressor provided on both sides before and after the reciprocating direction of the mover.

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