KR102087140B1 - Reciprocating compressor - Google Patents

Abstract

In the reciprocating compressor according to the present invention, a gas bearing for guiding a high-pressure refrigerant gas between the cylinder and the piston is formed in the cylinder, and a blocking protrusion or a blocking groove is formed on the outer circumferential surface of the piston or the inner circumferential surface of the cylinder, whereby A part of the refrigerant gas flowing between the pistons is blocked from entering the compression space during the suction stroke of the piston to reduce the suction loss in the compression space, thereby improving the performance of the compressor.

Description

Reciprocating Compressor {RECIPROCATING COMPRESSOR}

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

In general, a reciprocating compressor is a method in which a piston sucks and compresses a refrigerant while reciprocating in a straight line in a cylinder. The reciprocating compressor can be classified into a connection type and a vibration type according to the piston driving method.

In the connected reciprocating compressor, a piston is connected to a rotating shaft of a rotating motor by a connecting rod to compress refrigerant while reciprocating in a cylinder. On the other hand, in the vibration type reciprocating compressor, a piston is connected to a mover of a reciprocating motor and vibrates to reciprocate in a cylinder to compress the refrigerant. The present invention relates to a vibration type reciprocating compressor, hereinafter referred to as a vibration type reciprocating compressor.

The reciprocating compressor may be smoothly lubricated 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 consideration of the disadvantages of the oil-lubricated reciprocating compressor as described above, the piston 1 and the cylinder 2 by bypassing a part of the compressed gas between the piston 1 and the cylinder 2 as shown in FIGS. 1 and 2. There is a known technique for forming a gas bearing between the). The plurality of bearing holes 2a having a small diameter are penetrated to inject compressed gas into the inner circumferential surface of the cylinder 2.

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. In the drawings, reference numeral 3 denotes a leaf spring, 5a to 5c are connecting bars, and 6a and 6b are links.

However, in the conventional reciprocating compressor as described above, a part of the refrigerant gas flowing between the cylinder 2 and the piston 1 flows into the compression space during the suction stroke of the piston 1, and the high pressure flows into the compression space. Due to the increase in the specific volume of the compression space by the refrigerant gas of the refrigerant intake amount is reduced there is a problem that the compressor performance is reduced.

An object of the present invention is to provide a reciprocating compressor that can reduce the suction loss by blocking the refrigerant sucked between the cylinder and the piston to enter the compression space and thereby increase the compressor performance.

In order to achieve the object of the present invention, a cylinder having a compression space; A piston inserted into the cylinder to reciprocate to form a compression space, and a suction passage penetrating in the reciprocating direction so as to communicate with the compression space; And a gas bearing having a bearing hole penetrated through the cylinder to inject the refrigerant gas between the cylinder and the piston to support the piston with respect to the cylinder, wherein at least one of an inner circumferential surface of the cylinder or an outer circumferential surface of the piston is provided. A reciprocating compressor having a blocking portion may be provided to block the refrigerant gas from flowing into the compression space.

In the reciprocating compressor according to the present invention, since a blocking protrusion or a blocking groove is formed on the outer circumferential surface of the piston, a part of the refrigerant gas flowing between the cylinder and the piston through the bearing hole of the gas bearing is introduced into the compression space during the suction stroke of the piston. It is possible to block the increase and thereby prevent the specific volume of the compression space from rising, thereby reducing the suction loss in the compression space, thereby improving the compressor performance.

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 enlarged view of a portion “A” in FIG. 3, and is a cross-sectional view showing an embodiment of a gas bearing;
5 and 6 are a cross-sectional view showing an example of the gas through-hole provided in the piston in the reciprocating compressor according to Figure 2 and "II" cross-sectional view of FIG.
7 to 9 are longitudinal sectional and front views showing embodiments of the piston for explaining the interruption in the reciprocating compressor 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.

Figure 3 is a longitudinal sectional view of the reciprocating compressor of the present invention.

As shown in the drawing, in the reciprocating compressor according to the present embodiment, the suction pipe 12 is connected to the inner space of the casing 10, and the discharge pipe 13 is disposed in the discharge space S2 of the discharge cover 46, which will be described later. ) May be connected. The frame 20 is installed in the inner space 11 of the casing 10, the stator 31 and the cylinder 41 of the reciprocating motor 30 are fixed to the frame 20, and the reciprocating motor is mounted to the cylinder 41. A piston 42 coupled to the mover 32 of 30 is inserted and coupled to reciprocate, and a resonant spring 51 for inducing a resonant movement of the piston 42 on both sides of the piston 42 in the direction of movement. 52 may be installed respectively.

In addition, a compression space S1 is formed in the cylinder 41, a suction flow path F is formed in the piston 42, and a suction valve 43 which opens and closes the suction flow path F at the end of the suction flow path F. ) Is installed, the discharge valve 44 for opening and closing the compression space (S1) of the cylinder 41 may be installed on the front end surface of the cylinder (41).

In the reciprocating compressor according to the present embodiment as described above, when power is applied to the reciprocating motor 30, the mover 32 of the reciprocating motor 30 performs the reciprocating motion with respect to the stator 31. Then, the piston 42 coupled to the mover 32 sucks and compresses the refrigerant while discharging the refrigerant while linearly reciprocating in the cylinder 41.

In detail, when the piston 42 retreats, the refrigerant of the casing 10 is sucked into the compression space S1 through the suction channel F of the piston 42, and when the piston 42 is advanced, the suction channel F is advanced. ) Is closed and the refrigerant in the compression space (S1) is compressed. When the piston 42 is further advanced, the refrigerant compressed in the compression space S1 is discharged while opening the discharge valve 44 and moved to an external refrigeration cycle.

Here, the reciprocating motor 30 may be coupled to the coil 35 by being inserted into the stator 31, and an air gap may be formed on only one side of the coil 35. The mover 32 may include a magnet 36 inserted into the air gap of the stator 31 to reciprocate in the direction of movement of the piston.

The stator 31 is composed of a plurality of stator blocks 31a and a plurality of pole blocks 31b which are respectively coupled to one side of the stator block 31a to form a gap portion 31c together with the respective stator blocks 31a. Can be done.

The stator block 31a and the pole block 31b may be formed in an arc shape during axial projection by stacking a plurality of sheets of thin stator cores. In addition, the stator block 31a may be formed in a groove shape in the axial projection, and the pole block 31b may be formed in a rectangular shape in the axial projection.

The mover 32 may be formed of a magnet holder 32a formed in a cylindrical shape, and a plurality of magnets 36 coupled to the outer circumferential surface of the magnet holder 32a along the circumferential direction to form a magnetic flux together with the coil 35. have.

The magnet holder 32a is preferably formed of a nonmagnetic material to prevent magnetic flux leakage, but need not be limited to the nonmagnetic material. The outer circumferential surface of the magnet holder 32a may be formed in a circular shape so that the magnet 36 may be attached in line contact. In addition, a magnet mounting groove (not shown) may be formed in a band shape on the outer circumferential surface of the magnet holder 32a so that the magnet 36 may be inserted and supported in the movement direction.

The magnet 36 may be formed in a hexahedron shape and attached to the outer circumferential surface of the magnet holder 32a one by one. When the magnets 36 are attached one by one, the outer circumferential surface of the magnet 36 may be wrapped and fixed with a supporting member (not shown) such as a separate fixing ring or a tape made of a composite material.

The magnet 36 may be continuously attached to the outer circumferential surface of the magnet holder 32a along the circumferential direction, but the stator 31 is composed of a plurality of stator blocks 31a and the plurality of stator blocks 31a are circumferentially attached. Since the magnet 36 is also attached to have a predetermined interval along the circumferential direction, that is, between the stator blocks, on the outer circumferential surface of the magnet holder 32a, the magnet 36 may be minimized in use. It may be desirable.

And the magnet 36 is formed larger than the movement direction length of the cavity part 31c, so that the movement direction length is not smaller than the movement direction length of the cavity part 31c, and at least one side of the movement direction at the initial position or operation. It may be desirable for the end to be positioned so as to be located inside the cavity 31c for a stable reciprocating motion.

And only one magnet 36 in the movement direction may be arranged, in some cases may be arranged in a plurality in the movement direction. The magnet may be arranged to correspond to the N pole and the S pole in the movement direction.

The reciprocating motor as described above may be formed such that the stator has one air gap 31c, but in some cases, the stator may have air gaps (not shown) on both sides of the coil in the longitudinal direction. Also in this case, the mover may be formed in the same manner as in the above-described embodiment.

As shown in FIG. 3, the resonant springs include first and second resonant springs 51 and 52 installed at both front and rear sides of the spring supporter 53 coupled to the mover 32 and the piston 42, respectively. )

A plurality of first resonant springs 51 and second resonant springs 52 are provided, respectively, and are arranged along the circumferential direction. However, only one resonant spring may be provided in plurality among the first resonant spring 51 and the second resonant spring 52, and only one resonant spring may be provided.

As the first resonant spring 51 and the second resonant spring 52 are composed of compression coil springs as described above, side forces may be generated when the resonant springs 51 and 52 are stretched. have. Therefore, the resonant springs 51 and 52 may be arranged to cancel the side force or torsion moment 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, the first resonance springs 51 and the second resonance springs 52 may have ends thereof. At the same time as the center of the piston 42 is wound all the counterclockwise at the same position, the same resonant springs located in each diagonal direction to each other so that side force and torsion moment can be generated in opposite directions It can be arranged symmetrically to be tailored.

In addition, 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. .

Here, the spring fixing protrusions 531 so that the resonance springs 51 and 52 are press-fitted and fixed to the frame or the spring supporter 53 to which the ends of the first resonance springs 51 and the second resonance springs 52 are fixed. 532 is preferably formed 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, 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 lateral forces and the torsion moments generated at the respective resonant springs 51 and 52 are diagonally aligned. The offset of the piston 42 can be maintained by being offset by the symmetrical resonant spring, and the surface in contact with the resonant springs 51 and 52 can be prevented from being worn out.

In addition, as the resonant springs 51 and 52 apply a compression coil spring having a small longitudinal deformation without restraining the transverse direction of the piston 42, the compressor can be installed not only horizontally but also vertically, as well as the mover 32. There is no need to connect the piston 42 with a separate connecting bar or link, thereby reducing the material cost and assembly labor.

On the other hand, in the reciprocating compressor as described above, since the oil is not supplied between the cylinder 41 and the piston 42, the frictional loss between the cylinder 41 and the piston 42 must be reduced to increase the performance of the compressor. have. To this end, gas bearings are known which bypass a portion of the compressed gas between the inner circumferential surface of the cylinder 41 and the outer circumferential surface of the piston 42 to lubricate between the cylinder 41 and the piston 42 with gas force.

4 is an enlarged view of a portion “A” in FIG. 3, and is a cross-sectional view showing an embodiment of a gas bearing.

As shown in FIGS. 3 and 4, the gas bearing 100 communicates with the gas pocket 110 formed at a predetermined depth on the inner circumferential surface of the frame 20, and communicates with the gas pocket 110 of the cylinder 41. It may be formed of a plurality of rows of gas holes 120 formed through the inner circumferential surface. Here, the column of the gas holes 120 refers to the gas holes located at the same length in the longitudinal direction at the end of the cylinder 41, that is, formed on the same circumference.

The gas pocket 110 may be formed in an annular shape on the entire inner circumferential surface of the frame 20, but in some cases, a plurality of gas pockets 110 may be formed at predetermined intervals along the circumferential direction of the frame 20.

A gas guide part (not shown) for guiding a portion of the compressed gas discharged from the compression space into the discharge space S2 to the gas bearing 100 in the discharge space may be coupled to the inlet of the gas pocket 110.

Here, the gas pocket 110 may be formed between the frame 20 and the cylinder 41, but in some cases, the gas pocket 110 may be formed in the longitudinal direction of the cylinder at the front end surface of the cylinder 41. Since the gas pocket 110 is formed to be in direct communication with the discharge space S2 of the discharge cover 46, a separate gas guide part is not required, thereby simplifying the assembly process and reducing manufacturing costs.

On the other hand, in the present embodiment, the piston is formed longer than the length of the cylinder, so that the resonant spring is provided as a compression coil spring in spite of the increase in the self-weight of the piston, the deflection of the piston may occur due to the characteristics of the compression coil spring and thus the piston and Friction loss or wear may occur between the cylinders. In particular, in case of supporting the piston by supplying gas without supplying oil between the cylinder and the piston, the gas hole must be properly disposed to prevent the piston from sagging, thereby preventing friction loss or wear between the cylinder and the piston. Can be.

For example, the gas holes 120 penetrating into the inner circumferential surface of the cylinder 41 may be formed at regular intervals over the entire region in the longitudinal direction of the piston 42. That is, when the length of the piston 42 is longer than the length of the cylinder 41 and reciprocates in the lateral direction, the position of the gas hole 120 for injecting gas between the cylinder 41 and the piston 42 is defined as the compression space ( The front region and the center region of the piston 42 proximate to S1 may be formed evenly in the rear region of the piston 42. Accordingly, the gas bearing 100 can stably support the piston 41, thereby preventing the friction loss or abrasion between the cylinder 41 and the piston 42 from occurring.

Particularly, when the compression coil spring is applied to the resonant springs 51 and 52 that induce the resonant motion of the piston 42, the deflection of the piston may increase due to the lateral deformation due to the characteristics of the compression coil spring. As the 120 is formed evenly over the entire area along the longitudinal direction of the piston, the piston 42 does not sag and smoothly reciprocates to effectively prevent friction loss and wear between the cylinder 41 and the piston 42. Can be.

On the other hand, in the reciprocating compressor according to the present embodiment, the total cross sectional area of the gas holes disposed in the lower half of the cylinder should be larger than the total cross sectional area of the gas holes disposed in the upper half to prevent sagging of the piston, and thus, between the cylinder and the piston. To prevent friction loss and wear.

To this end, the number of gas holes located in the lower half of the gas holes 120 is greater than the number of gas holes located in the upper half, or the cross-sectional area of the gas holes located in the lower half is greater than the cross-sectional area of the gas holes located in the upper half. It can be formed large. In addition, the number of gas holes may be increased from the uppermost point to the lowermost point of the cylinder 41 so as to increase the number or the cross-sectional area thereof, thereby increasing the lower bearing force of the gas bearing.

In addition, a gas guide groove 125 may be formed at the inlet of the gas holes 120 to guide the compressed gas introduced into the gas pocket 110 to each gas hole 120 and serve as a buffer. . The gas guide grooves 125 may be formed in an annular shape so that the gas holes in each row communicate with each other, or a plurality of gas guide grooves 125 may be formed at regular intervals along the circumferential direction so that each gas hole in each row is independent of each other. However, it may be desirable to form the gas guide grooves 125 at regular intervals along the circumferential direction so that the gas guide grooves 125 are provided separately for each gas hole 120 because the compressed gas can be equalized and the strength of the cylinder can be compensated for.

On the other hand, when the diameter of the gas hole is small or sometimes fine foreign matter is caught in the gas hole, the refrigerant gas of the gas pocket may not flow smoothly into the bearing space between the cylinder and the piston. In view of this, it is possible to form a gas through hole in the piston. As a result, the pressure of the bearing space is lowered to allow the refrigerant gas of the gas pocket 110 to smoothly flow into the bearing space through the gas hole.

5 and 6 are cross-sectional views illustrating an example in which a gas through hole is provided in a piston in the reciprocating compressor according to FIG. 2 and a "I-I" sectional view of FIG. 5.

As shown in FIG. 5, the gas through holes 130 are formed at equal intervals along the circumferential direction, and may be formed to be in the same line in the reciprocating direction with the gas holes 120. In order to keep the distance between the holes 120 as far as possible, it may be preferable that the gas through holes 130 and the gas holes 120 are formed on different lines in the reciprocating direction. For example, as shown in FIG. 6, the gas through-hole 130 is positioned so that the gas through-hole 130 is positioned between the cylinder 41 and the piston 42 in the circumferential direction of the gas hole 120. And radially different lines.

On the other hand, when the gas bearing is applied as in the present embodiment, a high-pressure refrigerant gas is introduced between the cylinder and the piston, but a portion of the refrigerant gas flows into the compression space due to the pressure difference during the intake stroke of the piston, so that the body of the compression space is It increases the enemy, which can prevent the suction of new refrigerant gas into the compression space, which can cause the suction loss of the compressor.

In view of this, in the present embodiment, a blocking portion may be formed on the outer circumferential surface of the piston or the inner circumferential surface of the cylinder to prevent the refrigerant gas between the cylinder and the piston from flowing into the compression space.

7 to 9 are longitudinal cross-sectional and front views showing embodiments of the piston for explaining the blocking portion in the reciprocating compressor according to FIG. 4.

As shown in FIG. 7, the blocking part 140 may be formed of an annular blocking protrusion 141 protruding toward the inner circumferential surface of the cylinder 41 on the outer circumferential surface around the front end of the piston 42. In this case, if the height and width of the blocking protrusion 141 are too large, the friction loss with the cylinder 41 may increase or may interfere with the bearing hole 123 of the gas hole 120 to prevent the inflow of gas. If so, the blocking effect may be halved, so the height and width of the blocking protrusion 141 should be appropriately set.

In addition, as shown in FIG. 8, a plurality of embossing grooves 141a are formed on the outer circumferential surface of the blocking protrusion 141, and the refrigerant gas flows into the embossing grooves 141a to double the sealing effect or flow into the embossing grooves 141a. The bearing effect may be doubled by the refrigerant gas. In addition, although not shown in the drawings, one or a plurality of annular grooves may be formed at predetermined intervals in the blocking protrusion 141. In this case, similar effects to those of the embossed grooves described above can be achieved.

In addition, as shown in FIG. 9, the blocking part may be formed by recessing the outer peripheral surface around the front end of the piston 42 by a predetermined depth but having an annular blocking groove 142. In this case, only one blocking groove 142 may be formed, but in some cases, a plurality of blocking grooves 142 may be formed at a predetermined interval. As a result, the refrigerant gas destined for the compression space S1 is expanded to the blocking groove 142 and the pressure decreases, thereby preventing leakage of the refrigerant gas into the compression space.

As described above, when the blocking protrusion 141 or the blocking groove 142 is formed on the outer circumferential surface of the piston 42, between the cylinder 41 and the piston 42 through the bearing hole 123 of the gas hole 120. A portion of the high-pressure refrigerant gas flowing into the compression space S1 may be blocked when the piston 42 suctions the stroke. As a result, the specific volume of the compression space S1 may be prevented from rising, thereby reducing the suction loss in the compression space S1 and thus improving the compressor performance.

Here, although the blocking protrusion 141 or the blocking groove 142 is formed on the outer circumferential surface of the piston 42 in FIGS. 7 to 9, it may be formed in the same shape on the inner circumferential surface of the cylinder 41 in some cases. . Even in this case, the above-described embodiment and its operational effects can be about the same.

On the other hand, when the gas bearing is applied as in the present embodiment, when foreign matter mixed in the refrigerant flows into the gas hole, the foreign matter may prevent the refrigerant gas from flowing smoothly between the cylinder and the piston by blocking the bearing hole, which is a fine hole. have. In particular, when the oil is mixed into the refrigerant and flows into the gas bearing, the foreign matter may block the bearing hole firmly by the viscosity of the oil, thereby preventing the inflow of the refrigerant gas and increasing the wear or friction loss between the cylinder and the piston. Therefore, blocking the inflow of oil or foreign substances into the gas bearing may be important to increase the reliability of the compressor.

In view of this, the cross-sectional area of the bearing hole can be made small so as to prevent foreign matter from flowing into the bearing hole. However, if the cross-sectional area of the bearing hole is too small, it is rather undesirable that the bearing hole is blocked by foreign matters. On the other hand, it is possible to prevent the bearing hole from being blocked by foreign matter by increasing the cross-sectional area of the bearing hole, but a large amount of refrigerant gas flows into the gas hole, thereby increasing the compression loss, thereby reducing the compressor efficiency.

Therefore, in the present embodiment, as shown in FIG. 4, the flow path resistance part 300 is provided on the inlet side while the size of the bearing hole 123 is appropriately increased to block oil or foreign matter from flowing into the bearing hole 123. At the same time, compressor performance can be improved by limiting the ingress of compressed gas. The flow path resistance part 300 is formed by winding a thin line such as fabric or iron wire in the gas guide groove 125 a plurality of times, inserting a porous material, inserting a block at a predetermined distance from the gas guide groove, or the outer peripheral surface of the cylinder. It can be configured by forming a gas dispersion groove in the. As a result, it is possible to block the oil from flowing into the gas hole or to prevent the refrigerant from being excessively introduced into the gas hole.

On the other hand, in the above-described embodiments, even if 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, the positions of the bearing holes are the same. Can be applied. 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 provided on both sides of the piston in the movement direction, but in some cases, the cylinder is configured to reciprocate and the resonant springs on both sides of the cylinder. May be installed. Even in this case, the position of the bearing hole may be arranged as in the above-described embodiments. Detailed description thereof will be omitted.

20: frame 30: reciprocating motor
31: Stator 32: Mover
41 cylinder 42 piston
51,52: resonant spring 100: gas bearing
110: gas pocket 120: gas hole
123: bearing hole 125: gas guide groove
130: gas through hole 140: blocking unit
141: blocking protrusion 141a: embossed groove
142: blocking groove

Claims (5)

A cylinder having a compression space;
A piston inserted into the cylinder to form a compression space while reciprocating, and a suction passage penetrating in the reciprocating direction so as to communicate with the compression space; And
And a gas bearing in which a bearing hole is formed in the cylinder so as to support the piston with respect to the cylinder by injecting a refrigerant gas between the cylinder and the piston.
At least one of the inner circumferential surface of the cylinder or the outer circumferential surface of the piston is a reciprocating compressor having a blocking portion formed to block the refrigerant gas from entering the compression space. The method of claim 1,
The blocking unit is a reciprocating compressor is formed in a protrusion shape having a predetermined height along the circumferential direction of the cylinder or the circumferential direction of the piston. The method of claim 2,
At least one groove is formed in the blocking unit further reciprocating compressor. The method of claim 1,
And the blocking part is formed in a groove shape having a predetermined depth along the circumferential direction of the cylinder or the circumferential direction of the piston. The method of claim 1,
And the blocking portion is formed at a position closer to the compression space than the bearing hole closest to the compression space.

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