KR20180077774A - Reciprocating compressor - Google Patents

Abstract

According to an aspect of the present invention, a reciprocating compressor comprises: a cylinder forming a compression space of refrigerant; and a piston provided to reciprocate in an axial direction in the cylinder. In the piston, a suction port to enable the refrigerant to flow into the compression space is formed. The suction port comprises: an entrance portion provided in the piston for the refrigerant to flow into the suction port; and an exit portion provided toward the compression space for the refrigerant to be discharged from the suction port. Moreover, an area of the entrance portion is larger than that of the exit portion.

Description

RECIPROCATING COMPRESSOR

The present invention relates to a reciprocating compressor.

The cooling system is a system that generates cool air by circulating a coolant, and repeats the process of compressing, condensing, expanding, and evaporating the coolant. To this end, the cooling system includes a compressor, a condenser, an expansion device and an evaporator. The cooling system may be installed in a refrigerator or an air conditioner as a household appliance.

Generally, a compressor is a mechanical device that receives power from an electric motor or a power generating device such as a turbine and compresses air, refrigerant or various other working fluids to increase the pressure. The compressor is used for a household appliance such as a refrigerator and an air conditioner, It is widely used throughout.

The compressor is divided into a reciprocating compressor, a rotary compressor, and a scroll compressor according to a compression method of a working fluid.

Specifically, the reciprocating compressor includes a cylinder and a piston provided in the cylinder so as to be capable of reciprocating linearly. A compression space is formed between the piston head and the cylinder, and the compression space is increased or decreased by the linear reciprocating motion of the piston, so that the working fluid in the compression space is compressed to a high temperature and a high pressure.

Further, the rotary compressor includes a cylinder and a roller eccentrically rotating in the cylinder. The roller is eccentrically rotated in the cylinder to compress the working fluid supplied to the compression space to high temperature and high pressure.

Further, the scroll compressor includes a fixed scroll and a orbiting scroll that rotates around the fixed scroll. The orbiting scroll rotates and compresses the working fluid supplied to the compression space to a high temperature and a high pressure.

Recently, among the reciprocating compressors, there has been actively developed a linear compressor in which a piston is directly connected to a linear motor reciprocating linearly.

Specifically, the linear compressor is configured such that the piston reciprocates linearly in the cylinder by a linear motor in a closed shell, sucks the refrigerant into the compression space, compresses the compressed air, and then discharges the compressed refrigerant.

The linear motor is configured such that a permanent magnet is positioned between an inner stator and an outer stator, and the permanent magnet linearly reciprocates between the inner stator and the outer stator by an electromagnetic force. As the permanent magnet is driven in a connected state with the piston, the piston reciprocates linearly in the cylinder, sucks the refrigerant, compresses the refrigerant, and discharges the refrigerant.

Regarding a conventional linear compressor, the present applicant has been registered by applying a patent application (hereinafter referred to as Prior Art 1). As shown in the prior art document 1 attached below, a suction port formed in the axial direction of the conventional piston is formed.

1. Public number: 10-2015-0039992 (public date: April 14, 2015)

2. Title of the Invention:

At this time, the suction ports were formed in the piston to have the same cross-sectional area. That is, the inlet portion into which the refrigerant flows into the suction port and the outlet portion through which the refrigerant is discharged from the suction port are the same in shape.

The present invention provides a reciprocating compressor in which the inlet port and the outlet port have different suction ports. In particular, the present invention provides a reciprocating compressor which improves the response speed of a suction valve by increasing the pressure inside the piston by forming a suction port having a larger inlet area than the outlet.

The present invention also provides a reciprocating compressor in which the mass flow rate of refrigerant is increased and the cooling power is increased through a piston having a wider internal space.

A reciprocating compressor according to an aspect of the present invention includes a cylinder defining a compression space of a refrigerant and a piston provided in a reciprocating manner in an axial direction of the cylinder, Wherein the suction port is formed with an inlet portion provided inside the piston so that the refrigerant flows into the suction port and an outlet portion provided toward the compression space so as to discharge the refrigerant from the suction port, The area of the portion is larger than the area of the outlet portion.

As described above, as the area of the outlet portion is narrower than the area of the inlet portion, the pressure inside the piston increases, and the response speed of the intake valve can be improved.

In addition, the number of the inlet portions may be smaller than the number of the outlet portions. In particular, the inlet portion may be provided as one, and the outlet portion may be provided as a plurality.

The piston includes an inner front end portion formed with the inlet portion and a front end portion of the main body positioned forward of the inner front end portion and having the outlet portion, and the inner front end portion may be formed with a step recessed toward the front portion.

The inner front end portion includes a first surface, a second surface bent at the first surface, and a third surface bent outwardly from the second surface, the inner front end portion including a third surface A step may be formed such that a surface is formed on the front side of the first surface.

The length (L2) between the first surface and the third surface may be half the length (L1) between the first surface and the front end of the main body.

In other words, the axial length of the second surface may be half the axial length of the suction port.

The piston further includes a fastening member for coupling a suction valve for opening and closing the suction port to the piston and a fastening hole formed in the piston so that the fastening member is inserted into the piston, As shown in FIG.

The inlet portion may be formed along the outer periphery of the fastening hole, and the outlet portion may be formed on the outer side of the fastening hole so as to be spaced apart from each other. That is, the inlet portion may be formed as one, and the outlet portion may be formed as a plurality of spaced apart portions.

According to the present invention, the internal space of the piston is widened, and the mass flow rate of the refrigerant flowing through the piston is increased, thereby increasing the cooling power. As a result, there is an advantage that the efficiency of the compressor increases with the increase of the cooling power.

In addition, in the compressor having the same efficiency as the cooling power is increased, the reciprocating stroke of the piston can be reduced. Thereby, there is an advantage that the reliability of the compressor can be secured, for example, the collision between the piston and the peripheral device is prevented.

Further, as the inlet portion of the suction port is wider than the outlet portion, the pressure inside the piston is increased and the response speed of the suction valve can be improved.

Further, by forming a step in the piston to form an area difference between the inlet portion and the outlet portion, there is an advantage that the piston can be easily machined.

Further, there is an advantage in that strength of the piston can be secured by forming a step to be spaced apart from the fastening member at a predetermined interval.

1 is an external perspective view showing a configuration of a compressor according to an embodiment of the present invention.
2 is an exploded perspective view of a shell and a shell cover of a compressor according to an embodiment of the present invention.
3 is an exploded perspective view of internal components of a compressor according to an embodiment of the present invention.
4 is a cross-sectional view taken along line I-I 'of FIG.
5 is a perspective view illustrating a piston of a compressor according to an embodiment of the present invention.
6 is an exploded perspective view showing a piston structure of a compressor according to an embodiment of the present invention.
7 is a cross-sectional view taken along line II-II 'of FIG.
8 is a cross-sectional perspective view taken along line II-II 'of FIG.
9 is a rear view of a piston of a compressor according to an embodiment of the present invention.
10 is a table comparing suction port performance of the piston of the present invention and the conventional invention.

Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. It is to be understood, however, that the spirit of the invention is not limited to the embodiments shown and that those skilled in the art, upon reading and understanding the spirit of the invention, may easily suggest other embodiments within the scope of the same concept.

FIG. 1 is an external perspective view showing a structure of a compressor according to an embodiment of the present invention, and FIG. 2 is an exploded perspective view of a shell and a shell cover of a compressor according to an embodiment of the present invention.

Referring to FIGS. 1 and 2, a compressor 10 according to an embodiment of the present invention includes a shell 101 and shell covers 102 and 103 coupled to the shell 101. In a broad sense, the shell covers 102 and 103 can be understood as one configuration of the shell 101. [

On the lower side of the shell 101, the legs 50 can be engaged. The legs 50 may be coupled to the base of the product on which the compressor 10 is installed. For example, the product includes a refrigerator, and the base may include a machine room base of the refrigerator. As another example, the product may include an outdoor unit of the air conditioner, and the base may include a base of the outdoor unit.

The shell 101 has a substantially cylindrical shape, and can be arranged in a lateral direction or in an axial direction. 1, the shell 101 may be elongated in the transverse direction and may have a somewhat lower height in the radial direction. That is, since the compressor 10 can have a low height, when the compressor 10 is installed in the machine room base of the refrigerator, the height of the machine room can be reduced.

A terminal 108 may be provided on the outer surface of the shell 101. The terminal 108 is understood as a configuration for transmitting external power to the motor assembly 140 (see Fig. 3) of the linear compressor. In particular, the terminal 108 may be connected to the lead of the coil 141c (see FIG. 3).

On the outside of the terminal 108, a bracket 109 is provided. The bracket 109 may include a plurality of brackets surrounding the terminal 108. The bracket 109 may function to protect the terminal 108 from an external impact or the like.

Both sides of the shell 101 are configured to be open. On both sides of the opened shell 101, the shell covers 102 and 103 can be coupled. In detail, the shell covers 102 and 103 are provided with a first shell cover 102 coupled to one opened side of the shell 101 and a second shell cover 103 coupled to the other opened side of the shell 101 ). By the shell covers 102 and 103, the inner space of the shell 101 can be sealed.

1, the first shell cover 102 is located on the right side of the compressor 10, and the second shell cover 103 is located on the left side of the compressor 10. In other words, the first and second shell covers 102 and 103 may be disposed to face each other.

The compressor 10 further includes a plurality of pipes 104, 105 and 106 provided in the shell 101 or the shell covers 102 and 103 to suck, discharge or inject refrigerant.

The plurality of pipes 104, 105 and 106 are provided with a suction pipe 104 through which the refrigerant is sucked into the compressor 10, a discharge pipe 105 through which the compressed refrigerant is discharged from the compressor 10, A process pipe 106 for replenishing the compressor 10 is included.

For example, the suction pipe 104 may be coupled to the first shell cover 102. The refrigerant can be sucked into the compressor (10) along the axial direction through the suction pipe (104).

The discharge pipe 105 may be coupled to the outer circumferential surface of the shell 101. The refrigerant sucked through the suction pipe 104 can be compressed while flowing in the axial direction. The compressed refrigerant can be discharged through the discharge pipe 105. The discharge pipe 105 may be disposed at a position adjacent to the second shell cover 103 than the first shell cover 102.

The process pipe 106 may be coupled to the outer circumferential surface of the shell 101. The operator can inject the refrigerant into the compressor 10 through the process pipe 106.

The process pipe 106 may be coupled to the shell 101 at a different height than the discharge pipe 105 to avoid interference with the discharge pipe 105. The height is understood as a distance in a vertical direction (or a radial direction) from the legs 50. The discharge pipe (105) and the process pipe (106) are coupled to the outer circumferential surface of the shell (101) at different heights.

At least a portion of the second shell cover 103 may be positioned adjacent to the inner circumferential surface of the shell 101, corresponding to the point where the process pipe 106 is coupled. In other words, at least a portion of the second shell cover 103 may act as a resistance of the refrigerant injected through the process pipe 106.

Therefore, from the viewpoint of the flow path of the refrigerant, the flow path size of the refrigerant flowing through the process pipe 106 is reduced by the second shell cover 103 while entering the inner space of the shell 101, And is formed to be larger again. In this process, the pressure of the refrigerant can be reduced to vaporize the refrigerant, and in this process, the oil contained in the refrigerant can be separated. Therefore, the refrigerant compression performance can be improved while the oil-separated refrigerant flows into the interior of the piston 130 (see FIG. 3). The oil fraction can be understood as operating oil present in the cooling system.

On the inner surface of the first shell cover 102, a cover supporting portion 102a is provided. A second supporting device 185, which will be described later, may be coupled to the cover supporting portion 102a. The cover support portion 102a and the second support device 185 can be understood as devices for supporting the main body of the compressor 10. [ Here, the main body of the compressor refers to a part provided inside the shell 101, and may include, for example, a driving part moving forward and backward and a supporting part supporting the driving part. The driving unit may include components such as a piston 130, a magnet frame 138, a permanent magnet 146, a supporter 137, and a suction muffler 150, which will be described later. The support portion may include components such as resonance springs 176a and 176b, a rear cover 170, a stator cover 149, a first support device 165, and a second support device 185, which will be described later .

A stopper 102b may be provided on the inner surface of the first shell cover 102. [ The stopper 102b is understood to be a structure for preventing the main body of the compressor, particularly the motor assembly 140, from being damaged by collision with the shell 101 due to vibration or impact generated during transportation of the compressor 10 . The stopper 102b is positioned adjacent to a rear cover 170 to be described later so that when the compressor 10 vibrates, the rear cover 170 interferes with the stopper 102b, It is possible to prevent the shock from being transmitted to the first arm 140.

The inner circumferential surface of the shell 101 may be provided with a spring coupling portion 101a. For example, the spring engagement portion 101a may be disposed at a position adjacent to the second shell cover 103. The spring coupling portion 101a may be coupled to a first support spring 166 of a first support device 165, which will be described later. The main body of the compressor can be stably supported on the inner side of the shell 101 by the engagement of the spring coupling portion 101a and the first support device 165. [

FIG. 3 is an exploded perspective view of internal components of the compressor according to the embodiment of the present invention, and FIG. 4 is a cross-sectional view taken along line I-I 'of FIG.

3 and 4, the compressor 10 according to the embodiment of the present invention includes a cylinder 120 provided inside the shell 101 and a cylinder 120 provided inside the cylinder 120 for reciprocating linear motion And a motor assembly 140 as a linear motor that applies a driving force to the piston 130 and the piston 130. When the motor assembly 140 is driven, the piston 130 can reciprocate in the axial direction.

The compressor 10 further includes a suction muffler 150 connected to the piston 130 for reducing noise generated from the refrigerant sucked through the suction pipe 104. The refrigerant sucked through the suction pipe 104 flows into the piston 130 through the suction muffler 150. For example, in the course of the refrigerant passing through the suction muffler 150, the flow noise of the refrigerant can be reduced.

The suction muffler 150 includes a plurality of mufflers 151, 152 and 153. The plurality of mufflers 151, 152 and 153 include a first muffler 151, a second muffler 152 and a third muffler 153 coupled to each other.

The first muffler 151 is positioned inside the piston 130 and the second muffler 152 is coupled to the rear side of the first muffler 151. The third muffler 153 accommodates the second muffler 152 therein and may extend to the rear of the first muffler 151. From the viewpoint of the flow direction of the refrigerant, the refrigerant sucked through the suction pipe 104 can pass through the third muffler 153, the second muffler 152 and the first muffler 151 in order. In this process, the flow noise of the refrigerant can be reduced.

A muffler filter (not shown) may be positioned at an interface between the first muffler 151 and the second muffler 152. For example, the muffler filter may have a circular shape, and an outer circumferential portion of the muffler filter may be supported between the first and second mufflers 151 and 152.

Hereinafter, the directions are defined for convenience of explanation.

The term "axial direction" can be understood as a direction in which the piston 130 reciprocates, that is, a lateral direction in FIG. Of these "axial directions", the direction from the suction pipe 104 toward the compression space P, that is, the direction in which the refrigerant flows is referred to as "forward" and the opposite direction is defined as "rearward". For example, when the piston 130 moves forward, the compression space P can be compressed.

On the other hand, the term "radial direction" can be understood as a direction perpendicular to the direction in which the piston 130 reciprocates and in the longitudinal direction of Fig.

The piston 130 includes a substantially cylindrical piston body 131 and a piston flange 132 extending radially from the piston body 131. The piston body 131 reciprocates within the cylinder 120 and the piston flange 132 can reciprocate outside the cylinder 120.

The cylinder (120) is configured to receive at least a portion of the first muffler (151) and at least a portion of the piston body (131).

A compression space P in which the refrigerant is compressed by the piston 130 is formed in the cylinder 120. A suction port 133 for introducing a refrigerant into the compression space P is formed in a front portion of the piston body 131. The suction port 133 is selectively provided in front of the suction port 133, A suction valve 135 is provided. A coupling hole 135a (see FIG. 6) to which a predetermined coupling member 134 is coupled may be formed in a substantially central portion of the suction valve 135.

In addition, the compressor includes a discharge cover 160 and discharge valve assemblies 161 and 163. The discharge cover 160 is disposed in front of the compression space P to form a discharge space 160a for the refrigerant discharged from the compression space P. [ The discharge space 160a includes a plurality of spaces defined by inner walls of the discharge cover 160. The plurality of space portions are arranged in the front-rear direction and can communicate with each other.

The discharge valve assemblies 161 and 163 are coupled to the discharge cover 160 and selectively discharge the compressed refrigerant in the compression space P. The discharge valve assemblies 161 and 163 are provided with a discharge valve 161 that opens when the pressure in the compression space P becomes equal to or higher than the discharge pressure and causes the refrigerant to flow into the discharge space 160a, And a spring assembly 163 provided between the covers 160 to provide an elastic force in the axial direction.

The spring assembly 163 includes a valve spring 163a and a spring support portion 163b for supporting the valve spring 163a on the discharge cover 160. [ For example, the valve spring 163a may include a leaf spring. The spring support portion 163b may be integrally injection-molded into the valve spring 163a by an injection process.

The discharge valve 161 is coupled to the valve spring 163a and a rear portion or a rear surface of the discharge valve 161 is positioned to be capable of supporting the front surface of the cylinder 120. [ When the discharge valve 161 is supported on the front surface of the cylinder 120, the compression space P is maintained in a closed state. When the discharge valve 161 is separated from the front surface of the cylinder 120, The space P is opened so that the compressed refrigerant in the compression space P can be discharged.

That is, the compression space P is understood as a space formed between the suction valve 135 and the discharge valve 161. The suction valve 135 is formed on one side of the compression space P and the discharge valve 161 is provided on the opposite side of the compression space P, .

When the pressure in the compression space P becomes equal to or lower than the suction pressure in the reciprocating linear motion of the piston 130 in the cylinder 120, the suction valve 135 is opened, P). On the other hand, when the pressure in the compression space P becomes equal to or higher than the suction pressure, the refrigerant in the compression space P is compressed while the suction valve 135 is closed.

On the other hand, when the pressure in the compression space P becomes equal to or higher than the discharge pressure, the valve spring 163a is deformed forward to open the discharge valve 161, and the refrigerant is discharged from the compression space P , And is discharged to the discharge space of the discharge cover (160). When the discharge of the refrigerant is completed, the valve spring 163a provides a restoring force to the discharge valve 161 so that the discharge valve 161 is closed.

A cover pipe 162a is coupled to the discharge cover 160 to discharge the refrigerant flowing through the discharge space 160a of the discharge cover 160. [ For example, the cover pipe 162a may be made of a metal material.

A loop pipe 162b is further coupled to the cover pipe 162a to transmit the refrigerant flowing through the cover pipe 162a to the discharge pipe 105. [ One side of the loop pipe 162b may be coupled to the cover pipe 162a and the other side may be coupled to the discharge pipe 105. [

The loop pipe 162b is made of a flexible material and can be relatively long. The loop pipe 162b may extend from the cover pipe 162a along the inner circumferential surface of the shell 101 and may be coupled to the discharge pipe 105. [ In one example, the loop pipe 162b may have a coiled shape.

The compressor (10) further includes a frame (110). The frame 110 is understood as a structure for fixing the cylinder 120. For example, the cylinder 120 may be press-fitted into the inside of the frame 110. The cylinder 120 and the frame 110 may be made of aluminum or an aluminum alloy.

The frame 110 is disposed to surround the cylinder 120. That is, the cylinder 120 may be positioned to be received inside the frame 110. The discharge cover 160 may be coupled to the front surface of the frame 110 by fastening members.

The motor assembly 140 includes an outer stator 141 fixed to the frame 110 so as to surround the cylinder 120 and an inner stator 148 disposed apart from the inner stator 141 And a permanent magnet 146 positioned in the space between the outer stator 141 and the inner stator 148.

The permanent magnets 146 can reciprocate linearly by mutual electromagnetic forces with the outer stator 141 and the inner stator 148. The permanent magnets 146 may be formed of a single magnet having one pole or a plurality of magnets having three poles.

The permanent magnet 146 may be installed on the magnet frame 138. The magnet frame 138 has a substantially cylindrical shape and may be arranged to be inserted into a space between the outer stator 141 and the inner stator 148.

 4, the magnet frame 138 is coupled to the piston flange 132 and extends in the outer radial direction and can be bent forward. The permanent magnet 146 may be installed at a front portion of the magnet frame 138. Accordingly, when the permanent magnet 146 reciprocates, the piston 130 can reciprocate axially together with the permanent magnet 146.

The outer stator 141 includes coil winding bodies 141b, 141c and 141d and a stator core 141a. The coil windings 141b, 141c and 141d include a bobbin 141b and a coil 141c wound around the bobbin in the circumferential direction. The coil windings 141b, 141c and 141d further include a terminal portion 141d for guiding the power line connected to the coil 141c to be drawn out or exposed to the outside of the outer stator 141. The terminal portion 141d may be arranged to be inserted into a terminal insertion portion provided in the frame 110. [

The stator core 141a includes a plurality of core blocks formed by stacking a plurality of laminations in a circumferential direction. The plurality of core blocks may be disposed so as to surround at least a part of the coil winding body 141b, 141c, and 141d.

A stator cover 149 is provided at one side of the outer stator 141. That is, one side of the outer stator 141 may be supported by the frame 110 and the other side may be supported by the stator cover 149.

The stator cover 149 and the frame 110 are fastened by a cover fastening member 149a. The cover fastening member 149a may extend forward toward the frame 110 through the stator cover 149 and may be coupled to a fastening hole provided in the frame 110. [

The inner stator 148 is fixed to the outer periphery of the frame 110. The inner stator 148 is formed by laminating a plurality of laminations in the circumferential direction from the outside of the frame 110.

The compressor (10) further includes a supporter (137) for supporting the piston (130). The supporter 137 is coupled to the rear side of the piston 130 and the suction muffler 150 penetrates the inside of the supporter 137. The piston flange 132, the magnet frame 138, and the supporter 137 can be fastened by a fastening member.

To the supporter 137, a balance weight 179 may be combined. The weight of the balance weight 179 can be determined based on the operating frequency range of the compressor main body.

The compressor 10 further includes a rear cover 170 coupled to the stator cover 149 and extending rearwardly and supported by a second support device 185.

In detail, the rear cover 170 includes three supporting legs, and the three supporting legs can be coupled to the rear surface of the stator cover 149. [ A spacer 181 may be interposed between the three support legs and the rear surface of the stator cover 149. The distance from the stator cover 149 to the rear end of the rear cover 170 can be determined by adjusting the thickness of the spacer 181. The rear cover 170 may be spring-supported to the supporter 137.

The compressor 10 further includes an inflow guide unit 156 coupled to the rear cover 170 to guide inflow of refrigerant to the suction muffler 150. At least a portion of the inflow guide portion 156 may be inserted into the suction muffler 150.

The compressor (10) further includes a plurality of resonance springs (176a, 176b) whose natural frequencies are adjusted so that the piston (130) can resonate.

The plurality of resonance springs 176a and 176b are provided with a first resonance spring 176a supported between the supporter 137 and the stator cover 149 and a second resonance spring 176b between the supporter 137 and the rear cover 170 And a second resonance spring 176b supported. By the action of the plurality of resonance springs 176a and 176b, stable movement of the reciprocating drive unit is performed within the compressor 10, and vibration or noise generated by the movement of the drive unit can be reduced.

The supporter 137 includes a first spring support portion 137a coupled to the first resonance spring 176a.

The compressor 10 includes a plurality of sealing members 127, 128, 129a, and 129b for increasing a coupling force between the frame 110 and components around the frame 110.

Specifically, the plurality of sealing members 127, 128, 129a, and 129b includes a first sealing member 127 provided at a portion where the frame 110 and the discharge cover 160 are coupled. The first sealing member 127 may be disposed in the first mounting groove of the frame 110.

The plurality of sealing members 127, 128, 129a and 129b may further include a second sealing member 128 provided at a portion where the frame 110 and the cylinder 120 are coupled. The second sealing member 128 may be disposed in the second mounting groove of the frame 110.

The plurality of sealing members 127, 128, 129a and 129b further include a third sealing member 129a provided between the cylinder 120 and the frame 110. The third sealing member 129a may be disposed in a cylinder groove formed in a rear portion of the cylinder 120. [ The third sealing member 129a prevents the refrigerant in the gas pocket formed between the inner circumferential surface of the frame and the outer circumferential surface of the cylinder from leaking out and functions to increase the coupling force between the frame 110 and the cylinder 120 Can be performed.

The plurality of sealing members 127, 128, 129a and 129b may further include a fourth sealing member 129b provided at a portion where the frame 110 and the inner stator 148 are coupled. The fourth sealing member 129b may be disposed in the third installation groove of the frame 110. [ The first to fourth sealing members 127, 128, 129a, and 129b may have a ring shape.

The compressor 10 further includes a first support device 165 coupled to the discharge cover 160 and supporting one side of the main body of the compressor 10. The first support device 165 may be disposed adjacent to the second shell cover 103 to elastically support the main body of the compressor 10. In detail, the first supporting device 165 includes a first supporting spring 166. [ The first support spring 166 may be coupled to the spring coupling portion 101a described with reference to FIG.

The compressor 10 further includes a second support device 185 coupled to the rear cover 170 to support the other side of the main body of the compressor 10. [ The second support device 185 may be coupled to the first shell cover 102 to elastically support the main body of the compressor 10. Specifically, the second support device 185 includes a second support spring 186. The second support spring 186 may be coupled to the cover support portion 102a described with reference to FIG.

The cylinder 120 includes a cylinder body 121 extending in the axial direction and a cylinder flange 122 provided outside the front portion of the cylinder body 121. The cylinder body 121 has a cylindrical shape having a central axis in the axial direction, and is inserted into the frame 110. Therefore, the outer circumferential surface of the cylinder body 121 may be positioned to face the inner circumferential surface of the frame 110.

The cylinder body 121 is formed with a gas inlet 126 through which at least a portion of the refrigerant discharged through the discharge valve 161 flows. The at least a part of the refrigerant is understood as a refrigerant used as a gas bearing between the piston 130 and the cylinder 120. [

4, the refrigerant used as the gas bearing passes through the gas hole 114 formed in the frame 110, and flows between the inner peripheral surface of the frame 110 and the outer peripheral surface of the cylinder 120 Flows into the formed gas pocket. The refrigerant in the gas pocket may flow to the gas inlet 126.

In detail, the gas inlet 126 may be configured to sink radially inward from the outer circumferential surface of the cylinder body 121. The gas inlet 126 may have a circular shape along an outer circumferential surface of the cylinder body 121 with respect to an axially central axis. A plurality of gas inflow portions 126 may be provided. For example, two gas inflow portions 126 may be provided.

The cylinder body 121 includes a cylinder nozzle 125 extending radially inwardly from the gas inlet 126. The cylinder nozzle 125 may extend to the inner circumferential surface of the cylinder body 121.

The refrigerant having passed through the gas inlet 126 flows into the space between the inner circumferential surface of the cylinder body 121 and the outer circumferential surface of the piston body 131 through the cylinder nozzle 125. This refrigerant provides a levitation force to the piston 130 to perform the function of a gas bearing for the piston 130.

FIG. 5 is a perspective view illustrating a piston of a compressor according to an embodiment of the present invention, and FIG. 6 is an exploded perspective view illustrating a piston structure of a compressor according to an embodiment of the present invention.

As described above, the piston 130 is reciprocally provided in the cylinder 120 in the axial direction, that is, in the front-rear direction. The piston 130 has a substantially cylindrical shape and includes the piston body 131 extending in the front and rear direction and the piston flange 132 extending radially outward from the piston body 131.

The front end of the piston body 131 is provided with a main body front end 131a on which a fastening hole 131b is formed. The suction port 133 described above is formed in the front end portion 131a of the main body. A plurality of the suction ports 133 are formed, and the suction ports 133 are formed on the outer side of the fastening holes 131b. That is, the plurality of suction ports 133 may be disposed so as to surround the fastening holes 131b.

In one example, the plurality of suction ports 133 may include eight suction ports. Further, as shown in FIG. 6, the eight intake ports may be arranged in four directions with respect to the coupling hole 131b in pairs. The number, position, and shape of the suction ports are exemplary, and the suction ports may be provided in various forms.

The suction valve 135 is disposed at the front end of the suction port 133. The suction valve 135 includes a coupling hole 135a formed at the central portion and a wing portion 135b formed at the outer side of the coupling hole 135a.

The suction valve 135 is coupled to the fastening hole 131b through a predetermined fastening member 134. The coupling member 134 may be coupled to the piston body 131 through the coupling hole 135a. The coupling member 134 is coupled to the coupling hole 131b of the piston 130 through the coupling hole 135a of the suction valve 135. [

A plurality of wings 135b may be provided around the coupling hole 135a. In particular, the plurality of vanes 135b may be disposed at positions corresponding to the suction ports 133. [ Each suction port can be selectively opened and closed by one wing portion. For example, the plurality of vanes 135b may include four vanes to open and close a pair of suction ports, respectively.

A first piston groove (136a) is formed on the outer peripheral surface of the piston body (131). The first piston groove (136a) may be positioned forward with respect to the radial center line of the piston body (131). The first piston groove 136a can be understood as a structure provided to guide smooth flow of the refrigerant gas flowing through the cylinder nozzle 125 and to prevent pressure loss.

A second piston groove (136b) is formed on the outer peripheral surface of the piston body (131). The second piston groove (136b) may be positioned rearward with respect to the radial center line of the piston body (131). That is, it can be understood that the second piston groove 136b is disposed between the first piston groove 136a and the piston flange 132.

The second piston groove 136b can be understood as a "discharge guide groove" for guiding the discharge of the refrigerant gas used for lifting the piston 130 to the outside of the cylinder 120. [ The refrigerant gas is discharged to the outside of the cylinder 120 through the second piston groove 136b so that the refrigerant gas used for the gas bearing flows into the compression space P via the front of the piston body 131 It is possible to prevent re-inflow.

The piston flange 132 is provided with a flange body 132a extending radially outward from the rear portion of the piston body 131 and a piston coupling portion 132b further extending radially outward from the flange body 132a. .

The piston fastening portion 132b includes a piston fastening hole 132c to which a predetermined fastening member is coupled. The fastening member may pass through the piston fastening hole 132c and be coupled to the magnet frame 138 and the supporter 137. A plurality of the piston coupling portions 132b may be provided, and the plurality of piston coupling portions 132b may be spaced apart from each other and disposed on the outer peripheral surface of the flange main body 132a.

The rear portion of the piston body 131 is opened, and the refrigerant can be sucked. At least a part of the suction muffler 150 can be inserted into the interior of the piston body 131 through the rear portion of the opened piston body 131.

FIG. 7 is a cross-sectional view taken along II-II 'of FIG. 6, FIG. 8 is a cross-sectional perspective view taken along line II-II' of FIG. 6, . The fastening member 134 and the suction valve 135 are omitted for convenience.

As shown in FIGS. 7 and 8, the piston 130 has a predetermined storage space therein. The storage space is a space through which the refrigerant flows, and the refrigerant is introduced from the rear of the piston 130 and discharged forward. The refrigerant discharged toward the front of the piston 130 flows along the suction port 133.

7, the suction port 133 is provided with an inlet 133a provided in the piston 130 to allow the refrigerant to flow therethrough and an inlet 133a provided in the front end portion of the main body of the piston 130 And an outlet 133b provided in the outlet 131a. That is, the suction port 133 has the inlet 133a at one end and the outlet 133b at the other end.

The areas of the inlet 133a and the outlet 133b are different from each other. Specifically, the area of the inlet 133a is larger than the area of the outlet 133b. In this case, the area means the width in the radial direction.

Also, as shown in FIG. 8, the inlet 133a is provided as one, and the outlet 133b is formed as a plurality of. In other words, a step is formed in the inner front end portion 139 so that the inner space of the piston 130 is widened.

The inner front end portion 139 is formed to face the front end portion 131a of the main body portion and the outlet portion 133b is formed in the front end portion 131a of the main body. A portion 133a is formed.

The inner front end portion 139 includes first to fourth surfaces 139a to 139d disposed with respect to the center of the radius of the piston 130.

The first surface 139a is provided on the rear side of the coupling hole 131b and is disposed at the center of the radius of the piston 130. [ The first surface 139a may be spaced apart from the first end of the fastening member 134 when the fastening member 134 is inserted into the fastening hole 131b.

The second surface 139b is bent to extend from the first surface 139a and is provided to surround the outer side of the fastening hole 131b. The second surface 139b may be provided at a position spaced apart from the outer side of the fastening member 134 inserted when the fastening member 134 is inserted into the fastening hole 131b. As the first surface 139a and the second surface 139b are spaced apart from the fastening member 134 by a predetermined distance, the piston 130 is damaged by the coupling force of the fastening member 134 And the strength can be secured.

In addition, the second surface 139b may form an inner surface of the inlet 133a. As shown in FIG. 7, the second surface 139b may be formed to extend in the axial direction. However, this is exemplary and the second surface 139b may be extended at an angle to guide the flow of the refrigerant.

The third surface 139c is bent and extended from the second surface 139b. The refrigerant introduced into the inlet 133a is distributed to the respective suction ports 133 on the third surface 139c.

The fourth surface 139d is provided outside the inlet 133a. As shown in FIG. 7, the fourth surface 139d is located on the same line in the radial direction as the first surface 139a. The first surface 139a and the fourth surface 139d are spaced apart from each other by the width of the inlet portion 133a.

At this time, the length in the axial direction from the main body front end portion 133a to the first surface or the fourth surface is referred to as a suction port length L1. The axial length from the third surface to the first surface or the fourth surface is referred to as a suction step length L2. The suction step length L2 can be understood as a portion where a step is formed in the suction port 133 or a length of the inlet portion 133a.

The suction step length L2 may be more than half of the suction port length L1. For example, when the suction port length L1 is 10 mm, the suction step length L2 may be 5 mm. For example, the suction step length L2 may be less than the suction port length L1 and the main body front end 131a may be formed.

The process of forming the front portion of the piston 130 will be described. A plurality of passages are formed so that the areas of both ends are the same. That is, a plurality of passages extending in the axial direction are formed with the cross-sectional area of the exit portion 133b. Specifically, eight passages provided in four directions around the fastening holes 131b are formed.

An imaginary circle connecting the centers of the circles forming the cross-sectional areas of the respective passages, and an area of a circle spaced outwardly from the coupling holes at a predetermined interval, that is, the area of the first surface 139a. At this time, the distance between the spaced virtual circle and the spaced apart circle is depressed to form a step.

At this time, the inlet 133a is formed by the outside of the first surface 139a and the inside of the fourth surface 139d. Further, the inside of the fourth surface 139d is formed by an imaginary circle and an outer surface of a previously formed passage.

10 is a table comparing suction port performance of the piston of the present invention and the conventional invention.

In Fig. 10, the suction port mass flow rate and the suction port pressure of the present invention and the conventional invention are compared. At this time, the conventional invention refers to a suction port in which no step is formed, that is, the inlet and the outlet have the same area.

The conventional invention and the present invention are premised on having the same outlet portion. The compressor is assumed to have the same structure and conditions except for the shape of the inlet and the inner front end. At this time, the piston was measured to reciprocate at an average of 95 Hz per cycle.

The suction port mass flow rate refers to the mass flow rate of the refrigerant flowing through the suction port. At this time, the prior invention has an average suction port mass flow rate of about 0.1065 kg / s on average, and the present invention has an average suction port mass flow rate of about 0.1112 kg / s on average. Therefore, the suction port mass flow rate of the present invention is increased by about 4.4% as compared with the conventional invention.

Further, the suction port pressure means an average pressure of the outlet portion when the suction valve is opened. At this time, the prior art has an inlet port pressure of about 36660 Pa on average, and the present invention has an inlet port pressure of about 37000 Pa on average. Therefore, the suction port pressure of the present invention was increased by about 0.9% as compared with the conventional invention.

That is, in the compressor according to the embodiment of the present invention, the space in which the refrigerant flows is increased by forming a step on the inner front end portion. Therefore, the mass flow rate of the refrigerant can be increased and the cooling power can be increased. As a result, the efficiency of the compressor is increased.

Further, as the refrigerant is discharged through the suction port whose inlet portion has a larger area than the outlet portion, the pressure inside the suction port increases. Accordingly, the response speed of the intake valve can be improved and the efficiency can be improved.

10: compressor 130: piston
131: piston main body 131a: main body front end portion
131b: fastening hole 133: suction port
133a: inlet portion 133b: outlet portion
134: fastening member 135: suction port
139: Inner front end portion L1: Suction port length
L2: Suction step length

Claims (8)

A cylinder forming a compression space of the refrigerant,
And a piston provided to reciprocate axially within the cylinder,
The piston is provided with a suction port for introducing the refrigerant into the compression space,
In the suction port,
An inlet portion provided in the piston to allow the refrigerant to flow into the suction port,
An outlet portion provided toward the compression space for discharging refrigerant from the suction port,
Wherein an area of the inlet portion is larger than an area of the outlet portion. The method according to claim 1,
And the number of the inlet portions is smaller than the number of the outlet portions. The method according to claim 1,
In the piston,
An inner front end portion formed with the inlet portion,
A front end portion of the main body positioned forward of the inner front end portion and having the outlet portion,
Wherein the inner front end portion is formed with a depressed step toward the front portion. The method of claim 3,
In the inner front end portion,
A first surface,
A second surface bent at the first surface,
And a third surface bent outwardly from the second surface,
Wherein the inner front end portion is formed with a step so that the third surface is formed at a front portion of the first surface. 5. The method of claim 4,
Wherein a length (L2) between the first surface and the third surface is equal to or larger than half the length (L1) between the first surface and the front end of the main body. 5. The method of claim 4,
Wherein the axial length of the second surface is at least half the axial length of the suction port. The method according to claim 1,
In the piston,
A coupling member for coupling a suction valve for opening and closing the suction port to the piston,
Further comprising a fastening hole formed in the piston so as to insert the fastening member,
And the suction port is disposed outside the fastening hole. The method according to claim 6,
Wherein the inlet portion is formed along an outer circumference of the fastening hole,
Wherein a plurality of the outlet portions are formed on the outer side of the fastening holes.

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