CN113250938B

CN113250938B - Compressor

Info

Publication number: CN113250938B
Application number: CN202011442723.9A
Authority: CN
Inventors: 金泳成; 俞善准; 金炯锡; 朴真成
Original assignee: LG Electronics Inc
Current assignee: LG Electronics Inc
Priority date: 2020-02-12
Filing date: 2020-12-08
Publication date: 2023-06-13
Anticipated expiration: 2040-12-08
Also published as: KR102390579B1; CN113250938A; KR20210102645A

Abstract

The invention provides a compressor. A compressor according to an aspect of the present invention is a compressor for compressing and discharging a refrigerant sucked into an inside of a cylinder, the compressor including: a cylinder tube of a cylindrical shape; a piston disposed inside the cylinder tube and reciprocating in an axial direction; and a bush (bush) press-fitted to an inner side surface of the cylinder tube, wherein a difference between an outer diameter of the bush and an inner diameter of the cylinder tube is 80 μm to 120 μm before the bush is press-fitted to the cylinder tube.

Description

Compressor

Technical Field

The present invention relates to a compressor. And more particularly, to a linear compressor compressing a refrigerant by a linear reciprocation of a piston.

Background

In general, a compressor is a device that receives power from a power generating device such as a motor or a turbine and compresses a working fluid such as air or a refrigerant. Specifically, compressors have been widely used in the entire industry or home electric appliances, particularly in vapor compression refrigeration cycles (hereinafter, referred to as "refrigeration cycles") and the like.

Such compressors may be classified into a reciprocating compressor (Reciprocating compressor), a rotary compressor (Rotary compressor), and a scroll compressor (Scroll compressor) according to the manner in which the refrigerant is compressed.

The reciprocating compressor is a manner in which a compression space is formed between a piston and a cylinder, and fluid is compressed by linear reciprocation of the piston; a rotary compressor compresses fluid by means of a roller (roller) eccentrically rotating inside a cylinder; a scroll compressor is a system in which a pair of scroll plates formed in a spiral shape are engaged and rotated, thereby compressing a fluid.

Recently, among reciprocating compressors, a linear compressor (Linear Compressor) using linear reciprocating motion instead of a crankshaft is increasingly used. In the case of the linear compressor, since mechanical loss is less generated when converting rotary motion into linear reciprocating motion, there is an advantage in that efficiency of the compressor is improved and the structure is simple.

In the linear compressor, a cylinder tube is located inside a housing for forming a closed space to form a compression chamber, and a piston for covering the compression chamber is reciprocated inside the cylinder tube. The linear compressor repeatedly performs the following processes: the fluid in the closed space is sucked into the compression chamber during the time when the piston is at the Bottom Dead Center (BDC), and the fluid in the compression chamber is compressed and discharged during the time when the piston is at the Top Dead Center (TDC).

The compression unit and the driving unit are respectively arranged in the linear compressor, and the compression unit is resonantly moved by the resonant spring through the movement generated in the driving unit, and compresses and spits the refrigerant.

The piston of the linear compressor will repeatedly undergo a series of processes as follows: the refrigerant is sucked into the inside of the housing through the suction pipe while reciprocating at a high speed inside the cylinder tube by the resonance spring, and then discharged from the compression space by the forward movement of the piston, and then moved to the condenser through the discharge pipe.

On the other hand, the linear compressors may be classified into oil-lubricated linear compressors and gas-lubricated linear compressors according to the lubrication scheme.

The oil-lubricated linear compressor is configured such that a predetermined amount of oil is stored in a casing, and the oil is used to lubricate between a cylinder and a piston.

In contrast, the gas lubrication type linear compressor is configured such that a part of the refrigerant discharged from the compression space is guided between the cylinder and the piston without storing oil in the casing, and the cylinder and the piston are lubricated by the gas pressure of the refrigerant.

In the oil-lubricated linear compressor, since oil having a relatively low temperature is supplied between the cylinder and the piston, overheating of the cylinder and the piston due to heat of the motor, heat of compression, or the like can be suppressed. Thus, the oil-lubricated linear compressor can suppress the refrigerant passing through the suction passage of the piston from being sucked into the compression chamber of the cylinder tube and be heated to raise the specific volume (specific volume), thereby preventing the occurrence of suction loss in advance.

However, in the case where oil discharged into the refrigeration cycle apparatus together with the refrigerant is not smoothly recovered into the compressor in the oil-lubricated linear compressor, a phenomenon of oil shortage may occur in the casing of the compressor, and such a phenomenon of oil shortage occurring in the casing may cause a decrease in the reliability of the compressor.

In contrast, the gas lubrication type linear compressor can be miniaturized and lubricate between the cylinder tube and the piston with the refrigerant, compared with the oil lubrication type linear compressor, and thus, there is an advantage in that the reliability of the compressor is not lowered by oil shortage.

On the other hand, when the operation is performed at a high temperature of 100 ℃ or higher, the distance between the piston and the cylinder tube is shortened, and therefore there is a problem in that the piston and the cylinder tube collide.

Prior art literature

Patent literature

Patent document 1: korean patent publication No. 10-1484324B (bulletin day: 2015.01.20)

Disclosure of Invention

The present invention provides a compressor capable of preventing collision between a piston and a cylinder by maintaining a distance between the piston and the cylinder.

In order to achieve the above object, according to one aspect of the present invention, a compressor for compressing and discharging a refrigerant sucked into a cylinder tube, includes: a cylinder tube of a cylindrical shape; a piston disposed inside the cylinder tube and reciprocating in an axial direction; and a bush (bush) press-fitted to an inner side surface of the cylinder tube, wherein a difference between an outer diameter of the bush and an inner diameter of the cylinder tube is 80 μm to 120 μm before the bush is press-fitted to the cylinder tube.

Thereby, the collision between the piston and the cylinder can be prevented by maintaining the distance between the piston and the cylinder.

In addition, the difference between the size of the outer diameter of the bush and the size of the inner diameter of the cylinder may be between 80 μm and 90 μm before the bush is press-bonded to the cylinder.

In addition, a press-in band may be formed between the liner and the cylinder tube, and the compressor may satisfy the following formula 1, δ _T ＝δ _TD +δ _ED Beta, wherein delta _T Representing the total deformation, delta, of the inner diameter of the bushing _TD Indicating the amount of thermal deformation, delta, of the bushing _ED Represents the elastic deformation amount of the bushing, and β represents the elastic deformation coefficient of the bushing.

In addition, the liner may have a linear expansion coefficient greater than that of the cylinder.

Additionally, the yield strength (yield strength) of the liner may be greater than the yield strength of the cylinder.

The difference between the inner diameter of the bush and the outer diameter of the piston may be 5 μm or more at a temperature of 100 ℃.

In addition, the piston and the bush may be formed of materials different from each other.

In addition, the bush may be formed of cast iron material, and the piston may be formed of aluminum material.

In addition, the cylinder tube may be formed of an aluminum material, and the bush may be formed of a cast iron material.

The cylinder tube may be formed of an al—mg—si-based aluminum alloy.

In order to achieve the above object, according to one aspect of the present invention, a compressor for compressing and discharging a refrigerant sucked into a cylinder tube, includes: a cylinder tube of a cylindrical shape; a bush (bush) press-fitted to an inner side surface of the cylinder tube, wherein a difference between an outer diameter of the bush and an inner diameter of the cylinder tube is 80 μm to 120 μm before the bush is press-fitted to the cylinder tube.

In addition, a press-in band may be formed between the liner and the cylinder tube, and the compressor may satisfy the following formula 1, δ _T ＝δ _TD +δ _ED Beta, wherein delta _T Refers to the total deformation of the inner diameter of the bushing, delta _TD Refers to the thermal deformation amount, delta of the bushing _ED The elastic deformation amount of the bushing is referred to, and the elastic deformation coefficient of the bushing is referred to.

Additionally, the bushing may have a yield strength that is greater than the yield strength of the cylinder.

The cylinder tube may be formed of an al—mg—si-based aluminum alloy.

In order to achieve the above object, according to one aspect of the present invention, a compressor for compressing and discharging a refrigerant sucked into a cylinder tube, includes: a cylinder tube of a cylindrical shape; a piston disposed in the cylinder tube and reciprocating in an axial direction; and a bush (bush) press-fitted to an inner side surface of the cylinder, a press-fit belt may be formed between the bush and the cylinder, and the compressor may satisfy the following formula 1, δ _T ＝δ _TD +δ _ED Beta, wherein delta _T Refers to the total deformation of the inner diameter of the bushing, delta _TD Refers to the thermal deformation amount, delta of the bushing _ED The elastic deformation amount of the bushing is referred to, and the elastic deformation coefficient of the bushing is referred to.

In addition, the difference between the size of the outer diameter of the bush and the size of the inner diameter of the cylinder may be between 80 μm and 120 μm before the bush is press-coupled to the cylinder.

According to the present invention, it is possible to provide a compressor capable of preventing collision between a piston and a cylinder by maintaining a distance between the piston and the cylinder.

Drawings

Fig. 1 is a perspective view of a compressor according to an embodiment of the present invention.

Fig. 2 is a sectional view of a compressor according to an embodiment of the present invention.

Fig. 3 is a sectional view of a part of the constitution of a compressor according to an embodiment of the present invention.

Fig. 4 is an enlarged view of a portion a of fig. 3.

Fig. 5 is a cross-sectional view of a liner and cylinder of a compressor in accordance with an embodiment of the present invention.

Fig. 6 is a graph showing a gap between a temperature-based cylinder and a piston according to an embodiment of the present invention.

Fig. 7 is a graph showing the thermal deformation amount of the inner diameter of the bushing based on the thickness of the push-in belt according to an embodiment of the present invention.

Fig. 8 is a graph showing the linear expansion coefficient of a bushing based on the thickness of a push belt according to an embodiment of the present invention.

Description of the reference numerals

100: compressor 101: accommodation space

102: suction space 103: compression space

104: discharge space 110: shell (casting)

111: shell (shell) 112: first housing cover

113: second housing cover 114: suction tube

115: discharge pipe 115a: circulation pipe

116: first support spring 116a: suction guide

116b: suction side support member 116c: damping member

117: the second support spring 117a: support bracket

117b: the first support guide 117c: support cover

117d: the second support guide 117e: third support guide

118: resonant spring 118a: first resonant spring

118b: second resonant spring 119: spring support

119a: main body 119b: second joint part

119c: the support portion 120: frame

121: the main body 122: a first flange part

123: rear cover 123a: support bracket

130: the driving unit 131: outer stator

132: coil winding body 132a: spool

132b: coil 133: stator core

134: inner stator 135: moving part (mover)

136: magnet frame 136a: first joint part

137: stator cover 140: cylinder barrel

141: second flange portion 142: gas inflow port

150: piston 151: head part

152: guide 153: a third flange part

154: suction port 155: suction valve

160: muffler unit 161: suction muffler

161a: fourth flange portion 162: internal guide

170: discharge valve assembly 171: discharge valve

172: valve spring 180: discharge cap assembly

181: first discharge cap 182: second spitting cover

183: third discharge cap 200: bush (Bush)

210: press-in belt

Detailed Description

Hereinafter, embodiments disclosed in the present specification (discoser) will be described in detail with reference to the accompanying drawings, and the same or similar constituent elements are given the same reference numerals regardless of the drawing numbers, and repeated description thereof will be omitted.

In describing the embodiments disclosed in the present specification, if a certain component is referred to as being "connected" or "coupled" to another component, it should be understood that the component may be directly connected or coupled to the other component, but other components may be present therebetween.

In addition, in the process of describing the embodiments disclosed in the present specification, when it is determined that the detailed description of the related known technology will obscure the gist of the embodiments disclosed in the present specification, a detailed description thereof will be omitted. Further, the drawings are provided for the convenience of understanding the embodiments disclosed in the present specification, and the technical ideas disclosed in the present specification are not limited to the drawings, but include all modifications, equivalents, and alternatives made within the technical ideas and technical scope of the present invention.

On the other hand, the terms of the specification (discoser) may be replaced with terms of document, specification, description and the like.

Referring to fig. 1, a linear compressor 100 according to an embodiment of the present invention may include: a housing 111; and housing covers 112, 113 coupled to the housing 111. In a broad sense, it is understood that the housing covers 112, 113 are one constituent of the housing 111.

On the underside of the housing 111, legs 20 may be incorporated. The leg 20 may be coupled to a base of a product provided for the linear compressor 100. For example, the product may comprise a refrigerator and the base may comprise a base of a mechanical compartment of the refrigerator. As another example, the product may include an outdoor unit of an air conditioner, and the base may include a base of the outdoor unit.

The housing 111 may have a generally cylindrical shape, and may be laid laterally or longitudinally. Based on fig. 1, the housing 111 may extend long in the lateral direction and have a low height in the radial direction. That is, the linear compressor 100 may have a low height, and thus, for example, when the linear compressor 100 is provided to a base of a mechanical chamber of a refrigerator, there is an advantage in that the height of the mechanical chamber can be reduced.

The center axis of the housing 111 in the longitudinal direction coincides with the center axis of the main body of the compressor 100 described later, and the center axis of the main body of the compressor 100 coincides with the center axes of the cylinder 140 and the piston 150 that constitute the main body of the compressor 100.

On the outer surface of the housing 111, a terminal (terminal) 30 may be provided. The connection terminal 30 can supply an external power to the driving unit 130 of the linear compressor 100. Specifically, the connection terminal 30 may be connected to a lead wire of the coil 132 b.

A bracket 31 may be provided on the outside of the connection terminal 30. The bracket 31 may include: a plurality of brackets surrounding the terminal 30. The bracket 31 may perform a function of protecting the connection terminal 30 from an external impact or the like.

Both sides of the housing 111 may be opened. The case covers 112 and 113 may be coupled to both side portions of the case 111 having an opening. Specifically, the housing covers 112, 113 may include: a first case cover 112 coupled to one side of the case 111, which is open; and a second housing cover 113 coupled to the other side portion of the housing 111 which is open. The inner space of the housing 111 may be closed by

housing covers

112, 113.

Based on fig. 1, the first housing cover 112 may be located at the right side of the linear compressor 100, and the second housing cover 113 may be located at the left side of the linear compressor 100. In other words, the first housing cover 112 and the second housing cover 113 may be arranged to oppose each other. Further, it is understood that the first housing cover 112 is located on the suction side of the refrigerant, and the second housing cover 113 is located on the discharge side of the refrigerant.

The linear compressor 100 may include a plurality of

pipes

114, 115, 40, and the plurality of

pipes

114, 115, 40 are provided to the casing 111 or the casing covers 112, 113 and can suck, discharge, or inject a refrigerant.

The plurality of

tubes

114, 115, 40 may include: a suction pipe 114 for flowing the refrigerant into the inside of the linear compressor 100; a discharge pipe 115 for discharging the compressed refrigerant from the linear compressor 100; and a supplementary pipe 40 for supplementing the refrigerant to the linear compressor 100.

For example, the suction duct 114 may be coupled to the first housing cover 112. The refrigerant may be sucked into the inside of the linear compressor 100 in the axial direction via the suction pipe 114.

The discharge pipe 115 may be coupled to the outer circumferential surface of the housing 111. The refrigerant sucked through the suction pipe 114 may be compressed while flowing in the axial direction. Thereafter, the compressed refrigerant may be discharged through the discharge pipe 115. The discharge pipe 115 may be disposed closer to the second housing cover 113 than the first housing cover 112.

The supplementary tube 40 may be coupled to the outer circumferential surface of the housing 111. The operator can inject the refrigerant into the linear compressor 100 through the supplementary pipe 40.

The replenishment pipe 40 may be combined with the housing 111 at a different height from the discharge pipe 115 to avoid interference with the discharge pipe 115. Here, the height is understood to be a distance in the vertical direction from the leg portion 20. By coupling the discharge pipe 115 and the replenishment pipe 40 to the outer peripheral surface of the casing 111 at different heights from each other, convenience of work can be obtained.

At least a part of the second housing cover 113 may be adjacently disposed on an inner peripheral surface of the housing 111 corresponding to a position for coupling the supplementary pipe 40. In other words, at least a portion of the second housing cover 113 may function as resistance to the refrigerant injected through the replenishment pipe 40.

Therefore, from the viewpoint of the flow path of the refrigerant, the flow path of the refrigerant flowing in through the replenishment pipe 40 is formed such that the size of the flow path becomes smaller by the second housing cover 113 in the process of entering the inner space of the housing 111, and becomes larger again after passing through the second housing cover 113. In this process, the pressure of the refrigerant becomes small, so that vaporization of the refrigerant is achieved, and in this process, the oil contained in the refrigerant can be separated. Therefore, the refrigerant from which the oil is separated flows into the piston 150, and the compression performance of the refrigerant can be improved. The oil component is understood to be the working oil present in the cooling system.

Fig. 2 is a sectional view for explaining the structure of the compressor 100.

Next, a linear compressor according to the present invention will be described by taking as an example a compressor that sucks and compresses a fluid while performing linear reciprocation of a piston and discharges the compressed fluid.

The linear compressor may be a constituent of a refrigeration cycle, and the fluid to be compressed in the linear compressor may be a refrigerant circulated in the refrigeration cycle. The refrigeration cycle may include a condenser, an expansion device, an evaporator, and the like in addition to the compressor. Further, the linear compressor may be used as one component of a cooling system of a refrigerator, but is not limited thereto and may be widely used throughout the industry.

Referring to fig. 2, the compressor 100 may include: a housing 110; and a body accommodated in the inside of the case 110. The main body of the compressor 100 may include: a frame 120; a cylinder 140 fixed to the frame 120; a piston 150 that linearly reciprocates inside the cylinder 140; a driving unit 130 fixed to the frame 120 and providing driving force to the piston 150, and the like. The cylinder 140 and the piston 150 may also be referred to herein as

compression units

140, 150.

The compressor 100 may include: a bearing unit for reducing friction between the cylinder tube 140 and the piston 150. The bearing unit may be an oil bearing or a gas bearing. Alternatively, a mechanical bearing may be used as the bearing unit.

The main body of the compressor 100 may be elastically supported by support springs 116, 117, and the support springs 116, 117 are disposed at both end portions of the inside of the housing 110. The support springs 116, 117 may include: a first support spring 116 supporting the rear of the main body; and a second support spring 117 supporting the front of the main body. The support springs 116, 117 may comprise leaf springs. The support springs 116, 117 may support a plurality of internal components of the main body of the compressor 100 while being capable of absorbing vibration and impact generated with the reciprocating motion of the piston 150.

The housing 110 may form a closed space. The enclosed space may include: an accommodating space 101 for accommodating the sucked refrigerant; a suction space 102, wherein the suction space 102 is filled with a refrigerant before compression; a compression space 103 for compressing a refrigerant; and a discharge space 104, wherein the discharge space 104 is filled with the compressed refrigerant.

The refrigerant sucked from the suction pipe 114 connected to the rear side of the case 110 fills the accommodating space 101, and the refrigerant in the suction space 102 communicating with the accommodating space 101 is compressed in the compression space 103 and discharged to the discharge space 104, and is discharged to the outside through the discharge pipe 115 connected to the front side of the case 110.

The housing 110 may include: a housing 111 having both ends opened and formed in a substantially cylindrical shape elongated in the lateral direction; a first housing cover 112 coupled to a rear side of the housing 111; and a second housing cover 113 coupled to the front side of the housing 111. Here, it is understood that the front side refers to the direction in which the compressed refrigerant is discharged as the left side of the drawing; the rear side is the direction in which the refrigerant flows, which is the right side of the drawing. In addition, the first housing cover 112 or the second housing cover 113 may be formed integrally with the housing 111.

The housing 110 may be formed of a thermally conductive material. This can quickly release the heat generated in the internal space of the case 110 to the outside.

The first housing cover 112 may be coupled to the housing 111 in such a manner as to seal the rear side of the housing 111, and the suction duct 114 may be inserted into and coupled to the center of the first housing cover 112.

The rear side of the main body of the compressor 100 may be elastically supported by the first support spring 116 in the radius direction of the first housing cover 112.

The first support spring 116 may include a circular plate spring. The edge portion of the first support spring 116 may be elastically supported in the forward direction with respect to the rear cover 123 by a support bracket 123 a. The center portion of the first support spring 116 forming the opening may be supported in a rearward direction with respect to the first housing cover 112 by the suction guide 116 a.

A through flow path may be formed inside the suction guide 116 a. The suction guide 116a may be formed in a cylindrical shape. A central opening of the first support spring 116 may be coupled to a front side outer circumferential surface of the suction guide 116a, and a rear side end of the suction guide 116a may be supported by the first case cover 112. At this time, an additional suction side support member 116b may be provided between the suction guide 116a and the inner side surface of the first housing cover 112.

The rear side of the suction guide 116a may communicate with the suction pipe 114, and the refrigerant sucked through the suction pipe 114 may pass through the suction guide 116a and smoothly flow into a muffler unit 160 described later.

Between the suction guide 116a and the suction side support member 116b, a damping member 116c may be disposed. The damping member 116c may be formed of a rubber material or the like. Thereby, it is possible to block transmission of vibration, which may occur during suction of the refrigerant through the suction pipe 114, to the first housing cover 112.

The second housing cover 113 may be coupled to the housing 111 in such a manner as to seal the front side of the housing 111, and the discharge pipe 115 may be inserted through the circulation pipe 115a and coupled to the second housing cover 113. The refrigerant discharged from the compression space 103 may pass through the discharge cap assembly 180 and then be discharged to the refrigeration cycle through the circulation pipe 115a and the discharge pipe 115.

The front side of the main body of the compressor 100 may be elastically supported by the second support spring 117 in the radius direction of the housing 111 or the second housing cover 113.

The second support spring 117 may include a circular plate spring. The center portion of the second support spring 117 forming the opening can be supported in the rear direction with respect to the discharge cap assembly 180 by the first support guide 117 b. The edge portion of the second support spring 117 may be supported by a support bracket 117a in a forward direction with respect to the inner side surface of the housing 111 or the inner peripheral surface of the housing 111 adjacent to the second housing cover 113.

Unlike fig. 2, the edge portion of the second support spring 117 may be supported in the forward direction with respect to the inner side surface of the housing 111 or the inner peripheral surface of the housing 111 adjacent to the second housing cover 113 by an additional bracket (not shown) coupled to the second housing cover 113.

The first support guide 117b may be formed in a cylindrical shape. The cross section of the first support guide 117b may have a plurality of diameters. The front side of the first support guide 117b may be inserted into the central opening of the second support spring 117, and the rear side thereof may be inserted into the central opening of the discharge cap assembly 180. The support cover 117c may be coupled to the front side of the first support guide 117b via the second support spring 117. A cup-shaped second support guide 117d recessed toward the front may be coupled to the front side of the support cover 117 c. A cup-shaped third support guide 117e recessed rearward corresponding to the second support guide 117d may be coupled to the inner side of the second housing cover 113. The second support guide 117d may be inserted inside the third support guide 117e and supported in the axial and/or radial direction. At this time, a gap (gap) may be formed between the second support guide 117d and the third support guide 117e.

The frame 120 may include: a body portion 121 for supporting an outer peripheral surface of the cylinder 140; and a first flange portion 122 connected to one side of the body portion 121 and for supporting the driving unit 130. The frame 120 may be elastically supported to the housing 110 by the first and second support springs 116 and 117 together with the driving unit 130 and the cylinder 140.

The body portion 121 may surround the outer circumferential surface of the cylinder tube 140. The body portion 121 may be formed in a cylindrical shape. The first flange 122 may be formed to extend radially from the front end of the body 121.

The cylinder 140 may be coupled to the inner peripheral surface of the body 121. An inner stator 134 may be coupled to the outer circumferential surface of the body 121. For example, the cylinder 140 may be pressed and fixed to the inner circumferential surface of the body 121, and the inner stator 134 may be fixed using an additional fixing ring (not shown).

An outer stator 131 may be coupled to the rear surface of the first flange 122, and a discharge cap assembly 180 may be coupled to the front surface thereof. For example, the outer stator 131 and the discharge cap assembly 180 may be fixed by a mechanical coupling unit.

A bearing inlet groove 125a forming a part of the gas bearing may be formed on one side of the front surface of the first flange 122, a bearing communication hole 125b penetrating from the bearing inlet groove 125a toward the inner peripheral surface of the main body 121 may be formed, and a gas groove 125c communicating with the bearing communication hole 125b may be formed on the inner peripheral surface of the main body 121.

The bearing inlet groove 125a may be formed to be recessed at a predetermined depth along the axial direction, and the bearing communication hole 125b may be a hole having a smaller cross-sectional area than the bearing inlet groove 125a, and may be formed to be inclined toward the inner peripheral surface of the body portion 121. The gas groove 125c may be formed in an annular shape having a predetermined depth and an axial length on the inner peripheral surface of the body 121. In contrast, the gas groove 125c may be formed on the outer peripheral surface of the cylinder tube 140 that contacts the inner peripheral surface of the body 121, or may be formed entirely on the inner peripheral surface of the body 121 and the outer peripheral surface of the cylinder tube 140.

Further, a gas inlet 142 corresponding to the gas groove 125c may be formed in the outer peripheral surface of the cylinder 140. The gas inlet 142 forms a nozzle portion in the gas bearing.

On the other hand, the frame 120 and the cylinder 140 may be formed of aluminum or an aluminum alloy material.

The cylinder 140 may be formed in an open cylindrical shape at both ends thereof. The piston 150 may be inserted into the cylinder 140 through a rear end of the cylinder 140. The front end of the cylinder tube 140 may be closed by the discharge valve assembly 170. A compression space 103 may be formed between the cylinder tube 140, the front end portion of the piston 150, and the discharge valve assembly 170. The front end of the piston 150 may be referred to herein as a head (head) 151. When the piston 150 retreats, the volume of the compression space 103 increases, and when the piston 150 advances, the volume of the compression space 103 decreases. That is, the refrigerant flowing into the compression space 103 can be compressed when the piston 150 advances, and discharged through the discharge valve assembly 170.

The cylinder 140 may include: a second flange portion 141 disposed at the front end portion thereof. The second flange portion 141 may be bent toward the outside of the cylinder tube 140. The second flange portion 141 may extend along the outer circumferential direction of the cylinder tube 140. The second flange portion 141 of the cylinder 140 may be coupled with the frame 120. For example, a flange groove corresponding to the second flange portion 141 of the cylinder tube 140 may be formed at the front side end portion of the frame 120, and the second flange portion 141 of the cylinder tube 140 may be inserted into the flange groove and coupled by a coupling member.

On the other hand, a gas bearing member may be provided that can lubricate the gas between the cylinder tube 140 and the piston 150 by supplying the discharged gas to the interval between the outer peripheral surface of the piston 150 and the outer peripheral surface of the cylinder tube 140. The discharged gas between the cylinder tube 140 and the piston 150 provides a levitation force to the piston 150, thereby enabling friction generated between the piston 150 and the cylinder tube 140 to be reduced.

For example, the cylinder 140 may include a gas flow inlet 142. The gas inflow port 142 may communicate with a gas groove 125c formed in the inner peripheral surface of the body portion 121. The gas inflow port 142 may penetrate the cylinder 140 in a radial direction. The gas inflow port 142 may guide the compressed refrigerant flowing into the gas groove 125c between the inner circumferential surface of the cylinder 140 and the outer circumferential surface of the piston 150. In contrast, the gas groove 125c may be formed on the outer peripheral surface of the cylinder 140 in view of convenience in processing.

As for the gas inflow port 142, an inlet thereof may be formed wider, and an outlet thereof may be formed as a fine through hole, thereby functioning as a nozzle. A filter (not shown) for blocking inflow of foreign substances may be additionally provided at an inlet portion of the gas inflow port 142. The filter may be a mesh filter made of metal, or may be formed by winding a member such as a thread.

The gas inflow port 142 may be formed independently in plurality, or may be formed as an annular groove along which a plurality of outlets are formed at a predetermined interval. The gas inlet 142 may be formed only on the front side with respect to the axial middle of the cylinder 140. In contrast, the gas inlet 142 may be formed on the rear side with respect to the axial middle of the cylinder 140 in consideration of sagging of the piston 150.

The piston 150 is inserted into the rear of the cylinder tube 140 to form an open end and is disposed to close the rear of the compression space 103.

The piston 150 may include a head 151 and a guide 152. The head 151 may be formed in a disc shape. The head 151 may be partially open. The header 151 may divide the compression space 103. The guide 152 may extend rearward from an outer peripheral surface of the head 151. The guide 152 may be formed in a cylindrical shape. The guide 152 may be hollow, and a part of the front thereof may be sealed by the head 151. An opening may be formed at the rear of the guide 152 and connected with the muffler unit 160. The head 151 may be an additional member combined with the guide 152. In contrast, the head 151 and the guide 152 may be integrally formed.

The piston 150 may include a suction port 154. The suction port 154 may extend through the head 151. The suction port 154 may communicate the suction space 102 and the compression space 103 inside the piston 150. For example, the refrigerant flowing from the receiving space 101 into the suction space 102 inside the piston 150 may pass through the suction port 154 and be sucked into the compression space 103 between the piston 150 and the cylinder tube 140.

The suction port 154 may extend along an axial direction of the piston 150. The suction port 154 may be formed to be inclined with respect to the axial direction of the piston 150. For example, the suction port 154 may extend so as to be inclined with respect to a direction away from the central axis as going toward the rear of the piston 150.

The suction port 154 may be formed in a circular shape in cross section. The inner diameter of the suction port 154 may be formed to be fixed. In contrast, the suction port 154 may be formed as a long hole whose opening extends in the radial direction of the head 151, and whose inner diameter gradually increases toward the rear.

The suction port 154 may be formed in plural along any one or more of the radial direction and the circumferential direction of the head 151.

A suction valve 155 for selectively opening and closing the suction port 154 may be installed at the head 151 of the piston 150 adjacent to the compression space 103. The suction valve 155 may be operated by elastic deformation to open or close the suction port 154. That is, the suction valve 155 may be elastically deformed to open the suction port 154 by the pressure of the refrigerant flowing to the compression space 103 through the suction port 154.

The piston 150 may be coupled to the mover 135. The mover 135 may reciprocate in the front-rear direction along with the movement of the piston 150. Between the mover 135 and the piston 150, an inner stator 134 and a cylinder 140 may be disposed. The mover 135 and the piston 150 may be connected to each other via a magnet frame 136, the magnet frame 136 being formed to bypass the cylinder 140 and the inner stator 134 toward the rear.

The muffler unit 160 may be combined with the rear of the piston 150 so as to attenuate noise generated during the suction of the refrigerant into the piston 150. The refrigerant sucked through the suction pipe 114 may pass through the muffler unit 160 and flow into the suction space 102 inside the piston 150.

The muffler unit 160 may include: a suction muffler 161 communicating with the accommodation space 101 of the housing 110; an inner guide 162 connected to the front of the suction muffler 161 and for guiding the refrigerant to the suction port 154.

The suction muffler 161 may be located at the rear of the piston 150, a rear side opening of the suction muffler 161 may be disposed adjacent to the suction pipe 114, and a front side end of the suction muffler 161 may be coupled to the rear of the piston 150. The suction muffler 161 forms a flow path in the axial direction, and thereby can guide the refrigerant in the accommodating space 101 to the suction space 102 inside the piston 150.

Inside the suction muffler 161, a plurality of noise spaces partitioned by a baffle (buffer) may be formed. The suction muffler 161 may be formed by combining two or more members with each other, for example, a plurality of noise spaces may be formed by pressing and combining a second suction muffler into the interior of a first suction muffler. Further, the suction muffler 161 may be formed of a plastic material in consideration of weight and insulation.

One side of the inner guide 162 may communicate with the noise space of the suction muffler 161, and the other side thereof may be deeply inserted into the interior of the piston 150. The inner guide 162 may be formed in a pipe (pipe) shape. Both ends of the inner guide 162 may have the same inner diameter. The inner guide 162 may be formed in a cylindrical shape. In contrast, the inner diameter of the front end of the inner guide 162, which is the discharge side, may be larger than the inner diameter of the rear end, which is the opposite side.

The suction muffler 161 and the inner guide 162 may be provided in various shapes, by which the pressure of the refrigerant passing through the muffler unit 160 can be adjusted. The suction muffler 161 and the inner guide 162 may be integrally formed.

The discharge valve assembly 170 may include: a discharge valve 171; and a valve spring 172 that is provided on the front side of the discharge valve 171 and elastically supports the discharge valve 171. The discharge valve assembly 170 may selectively discharge the refrigerant compressed in the compression space 103. Here, the compression space 103 refers to a space formed between the suction valve 155 and the discharge valve 171.

The discharge valve 171 may be configured to be supportable on the front surface of the cylinder 140. The discharge valve 171 can selectively open and close the front opening of the cylinder 140. The discharge valve 171 may be operated by elastic deformation, and thus can open or close the compression space 103. The discharge valve 171 can be elastically deformed by the pressure of the refrigerant flowing into the discharge space 104 through the compression space 103, thereby opening the compression space 103. For example, in a state where the discharge valve 171 is supported on the front surface of the cylinder 140, the compression space 103 may be kept closed, and in a state where the discharge valve 171 is spaced apart from the front surface of the cylinder 140, the compressed refrigerant of the compression space 103 may be discharged toward the opened space.

The valve spring 172 may be disposed between the discharge valve 171 and the discharge cap assembly 180, and provide an elastic force in an axial direction. The valve spring 172 may be a compression coil spring, or a leaf spring may be used in consideration of space occupation or reliability.

When the pressure in the compression space 103 is equal to or higher than the discharge pressure, the valve spring 172 deforms forward, and the discharge valve 171 is opened, so that the refrigerant can be discharged from the compression space 103 and toward the first discharge space 104a of the discharge cap assembly 180. When the discharge of the refrigerant is completed, the valve spring 172 provides a restoring force to the discharge valve 171, thereby closing the discharge valve 171.

Hereinafter, a process in which the refrigerant flows into the compression space 103 through the suction valve 155 and the refrigerant in the compression space 103 is discharged into the discharge space 104 through the discharge valve 171 will be described specifically.

When the pressure of the compression space 103 is equal to or lower than the preset suction pressure during the reciprocating rectilinear motion of the piston 150 inside the cylinder 140, the suction valve 155 is opened, and thus the refrigerant is sucked into the compression space 103. In contrast, if the pressure of the compression space 103 exceeds the preset suction pressure, the refrigerant of the compression space 103 is compressed in a state where the suction valve 155 is closed.

On the other hand, when the pressure in the compression space 103 is equal to or higher than the preset discharge pressure, the valve spring 172 deforms forward, and the discharge valve 171 connected thereto is opened, so that the refrigerant is discharged from the compression space 103 to the discharge space 104 of the discharge cap assembly 180. When the discharge of the refrigerant is completed, the valve spring 172 provides a restoring force to the discharge valve 171, and thereby the discharge valve 171 is closed, thereby sealing the front of the compression space 103.

The discharge cap assembly 180 may be disposed in front of the compression space 103, form a discharge space 104 for accommodating the refrigerant discharged from the compression space 103, and may be coupled to the front of the frame 120, thereby attenuating noise generated during discharge of the refrigerant from the compression space 103. The discharge cap assembly 180 may be coupled to the front of the first flange 122 of the frame 120 while accommodating the discharge valve assembly 170. For example, the discharge cap assembly 180 may be coupled to the first flange 122 by a mechanical coupling member.

Further, between the discharge cap assembly 180 and the frame 120, there may be provided: a gasket 165 for thermal insulation; and an O-ring (O-ring) 166 for suppressing leakage of the refrigerant in the discharge space 104.

The discharge cap assembly 180 may be formed of a thermally conductive material. Therefore, when the high-temperature refrigerant flows into the discharge cap assembly 180, heat of the refrigerant is transferred to the casing 110 through the discharge cap assembly 180 and is released to the outside of the compressor.

The discharge cap assembly 180 may be formed of one discharge cap, or may be configured such that a plurality of discharge caps are sequentially connected. In the case where the discharge cap assembly 180 is configured by a plurality of discharge caps, the discharge space 104 may include a plurality of space portions partitioned by the respective discharge caps. The plurality of space portions may be arranged along the front-rear direction and communicate with each other.

For example, in the case where there are three discharge caps, the discharge space 104 may include: a first discharge space 104a formed between the frame 120 and a first discharge cap 181 coupled to the front side of the frame 120; a second discharge space 104b which communicates with the first discharge space 104a and is formed between a second discharge cap 182 coupled to the front side of the first discharge cap 181 and the first discharge cap 181; and a third discharge space 104c communicating with the second discharge space 104b and formed between the third discharge cap 183 and the second discharge cap 182 coupled to the front side of the second discharge cap 182.

The first discharge space 104a may be selectively communicated with the compression space 103 by the discharge valve 171, the second discharge space 104b may be communicated with the first discharge space 104a, and the third discharge space 104c may be communicated with the second discharge space 104 b. As a result, the refrigerant discharged from the compression space 103 attenuates discharge noise as it passes through the first discharge space 104a, the second discharge space 104b, and the third discharge space 104c in this order, and is discharged to the outside of the casing 110 through the circulation pipe 115a and the discharge pipe 115 that communicate with the third discharge cap 183.

The driving unit 130 may include: an outer stator (out stator) 131 configured to surround the main body portion 121 of the frame 120 between the housing 111 and the frame 120; an inner stator 134 configured to surround the cylinder 140 between the outer stator 131 and the cylinder 140; and a mover 135 disposed between the outer stator 131 and the inner stator 134.

The outer stator 131 may be coupled to the rear of the first flange portion 122 of the frame 120, and the inner stator 134 may be coupled to the outer circumferential surface of the body portion 121 of the frame 120. Also, the inner stator 134 may be disposed toward the inside of the outer stator 131, and the mover 135 may be disposed in a space between the outer stator 131 and the inner stator 134.

A winding coil may be provided at the outer stator 131, and the mover 135 may include a permanent magnet. The permanent magnet may be constituted by a single magnet having one pole, or may be constituted by combining a plurality of magnets having three poles.

The outer stator 131 may include: a coil wound body 132 surrounding the axial direction along the circumferential direction; and a stator core 133 laminated so as to surround the coil winding body 132. The coil winding body 132 may include: a bobbin (bobbin) 132a having a hollow cylindrical shape inside; and a coil 132b wound along the circumferential direction of the bobbin 132 a. The coil 132b may be formed in a circular or polygonal cross section, and may be hexagonal in shape, for example. The stator core 133 may be formed by radially stacking a plurality of laminated plates (lamination sheets), or may be formed by stacking a plurality of lamination blocks (lamination blocks) in the circumferential direction.

The front side of the outer stator 131 may be supported to the first flange portion 122 of the frame 120, and the rear side thereof may be supported to the stator cover 137. For example, the stator cover 137 may have a disk shape of which the inside is hollow, and the outer stator 131 may be supported on the front surface of the stator cover 137 and the resonant spring 118 may be supported on the rear surface of the stator cover 137.

The inner stator 134 may be formed by stacking a plurality of laminations on the outer circumferential surface of the body portion 121 of the frame 120 in the circumferential direction.

One side of the mover 135 may be supported in combination with the magnet frame 136. The magnet frame 136 may have a substantially cylindrical shape and be configured to be inserted into a space between the outer stator 131 and the inner stator 134. Also, the magnet frame 136 may be provided to be combined with the rear side of the piston 150 and move together with the piston 150.

As an example, the rear end portion of the magnet frame 136 is bent and extended toward the inside in the radial direction to form the first coupling portion 136a, and the first coupling portion 136a may be coupled to the third flange portion 153 formed at the rear of the piston 150. The first coupling portion 136a of the magnet frame 136 and the third flange portion 153 of the piston 150 may be coupled by a mechanical coupling member.

Further, a fourth flange portion 161a formed in front of the suction muffler 161 may be provided between the third flange portion 153 of the piston 150 and the first coupling portion 136a of the magnet frame 136. Accordingly, the piston 150, the muffler unit 160, and the mover 135 can linearly reciprocate together in a combined state.

When a current is applied to the driving unit 130, a magnetic flux (magnetic flux) is formed on the winding coil, and an electromagnetic force is generated by an interaction between the magnetic flux of the winding coil formed at the outer stator 131 and the magnetic flux formed by the permanent magnet of the mover 135, thereby enabling the mover 135 to move. The piston 150 connected to the magnet frame 136 also reciprocates in the axial direction integrally with the mover 135, along with the axial reciprocation of the mover 135.

On the other hand, the driving unit 130 and the compressing

units

140, 150 may be supported by the supporting

springs

116, 117 and the resonance springs 118 in the axial direction.

The resonant spring 118 can achieve effective compression of the refrigerant by increasing vibration generated by the reciprocating motion of the mover 135 and the piston 150. Specifically, the piston 150 may be made to perform a resonance motion by adjusting the resonance spring 118 to a vibration frequency corresponding to the natural vibration frequency of the piston 150. In addition, the resonant spring 118 can stably move the piston 150, thereby reducing the occurrence of vibration and noise.

The resonant spring 118 may be a coil spring extending in an axial direction. The two ends of the resonant spring 118 may be connected to the vibrator and the fixed body, respectively. For example, one end of the resonant spring 118 may be connected to the magnet frame 136, and the other end thereof may be connected to the rear cover 123. Accordingly, the resonance spring 118 may be elastically deformed between a vibrator that generates vibration at one end portion of the resonance spring 118 and a fixed body that is fixed to the other end portion of the resonance spring 118.

The natural frequency of the resonant spring 118 may be designed to coincide with the resonant frequency of the mover 135 and the piston 150 when the compressor 100 is operated, thereby enabling an increase in the reciprocating motion of the piston 150. However, the rear cover 123, which is provided as a fixed body here, is elastically supported to the housing 110 by the first support spring 116, and thus is strictly said to be not fixed.

The resonant spring 118 may include a first resonant spring 118a and a second resonant spring 118b, the first resonant spring 118a being supported on the rear side and the second resonant spring 118b being supported on the front side with reference to the spring support 119.

The spring support 119 may include: a main body portion 119a surrounding the suction muffler 161; a second coupling portion 119b bent from the front of the main body portion 119a toward the inside in the radial direction; and a support portion 119c bent outward in the radial direction from the rear of the body portion 119 a.

The front surface of the second coupling portion 119b of the spring supporter 119 may be supported by the first coupling portion 136a of the magnet frame 136. The inner diameter of the second coupling portion 119b of the spring support 119 may surround the outer diameter of the suction muffler 161. For example, the second coupling portion 119b of the spring supporter 119, the first coupling portion 136a of the magnet frame 136, and the third flange portion 153 of the piston 150 may be coupled by a mechanical coupling member into one body after being sequentially disposed. At this time, as described previously, the fourth flange portion 161a of the suction muffler 161 may be disposed between the third flange portion 153 of the piston 150 and the first coupling portion 136a of the magnet frame 136 and fixed together.

The first resonant spring 118a may be disposed between a front surface of the rear cover 123 and a rear surface of the spring supporter 119. The second resonant spring 118b may be disposed between a rear surface of the stator cover 137 and a front surface of the spring supporter 119.

The first resonant spring 118a and the second resonant spring 118b may be arranged in plurality along the circumferential direction of the central axis. The first resonant spring 118a and the second resonant spring 118b may be disposed in parallel along the axial direction or may be disposed offset from each other. The first resonant spring 118a and the second resonant spring 118b may be arranged at predetermined intervals along the radiation direction of the central axis. For example, the first resonant spring 118a and the second resonant spring 118b are provided with three, respectively, and are arranged at intervals of 120 degrees along the radiation direction of the center axis.

The compressor 100 may include a plurality of sealing members: a plurality of the sealing members serve to increase the coupling force between the frame 120 and a plurality of parts of the periphery thereof.

For example, the plurality of sealing members may include: a first sealing member which is provided at a portion where the frame 120 and the discharge cap assembly 180 are coupled, and which is inserted into a setting groove provided at a front end portion of the frame 120; and a second sealing member provided at a combined portion of the frame 120 and the cylinder 140 and inserted into a disposition groove provided at an outer side surface of the cylinder 140. The second sealing member serves to prevent the refrigerant in the gas groove 125c formed between the inner circumferential surface of the frame 120 and the outer circumferential surface of the cylinder 140 from leaking to the outside, and can increase the coupling force between the frame 120 and the cylinder 140. The plurality of sealing members may further include a third sealing member provided at a combined portion of the frame 120 and the inner stator 134 and inserted into a disposition groove provided at an outer side surface of the frame 120. Here, the first to third sealing members may have a ring shape.

The operation state of the linear compressor 100 described above is as follows.

First, if a current is applied to the driving unit 130, a magnetic flux may be formed at the outer stator 131 due to the current flowing through the coil 132 b. The magnetic flux formed at the outer stator 131 generates electromagnetic force, and the mover 135 provided with the permanent magnet linearly reciprocates due to the generated electromagnetic force. Such electromagnetic force is alternately generated in two directions, that is, in a direction (front direction) in which the piston 150 is directed toward a Top Dead Center (TDC) when the compression stroke is performed, and in a direction (rear direction) in which the piston 150 is directed toward a bottom dead center (BDC, bottom dead center) when the suction stroke is performed. That is, the driving unit 130 may generate a force pushing the force of the mover 135 and the piston 150 in the moving direction, i.e., a pushing force.

The piston 150, which linearly reciprocates inside the cylinder tube 140, can repeatedly increase or decrease the volume of the compression space 103.

If the piston 150 moves in a direction (backward direction) in which the volume of the compression space 103 increases, the pressure of the compression space 103 may decrease. At this time, the suction valve 155 installed at the front of the piston 150 is opened, and thus the refrigerant staying in the suction space 102 is sucked into the compression space 103 along the suction port 154. Such a suction stroke may be performed until the piston 150 maximizes the volume increase of the compression space 103 and is located at the bottom dead center.

The piston 150 reaching the bottom dead center converts its movement direction and moves in a direction (forward direction) to reduce the volume of the compression space 103 while performing the compression stroke. When the compression stroke is performed, the pressure of the compression space 103 will increase, whereby the sucked refrigerant is compressed. When the pressure in the compression space 103 reaches the set pressure, the discharge valve 171 is pushed out by the pressure in the compression space 103 to open the cylinder tube 140, and the refrigerant can be discharged into the discharge space 104 through the partitioned space. Such a compression stroke may be continuously performed until the piston 150 moves to the top dead center where the volume of the compression space 103 is reduced to the minimum.

While repeating the suction stroke and the compression stroke of the piston 150, the refrigerant flowing into the accommodating space 101 inside the compressor 100 through the suction pipe 114 may sequentially pass through the suction guide 116a, the suction muffler 161, and the inner guide 162 and flow into the suction space 102 inside the piston 150, and the refrigerant of the suction space 102 may flow into the compression space 103 inside the cylinder 140 when the piston 150 performs the suction stroke. During the compression stroke of the piston 150, a flow is formed in which the refrigerant in the compression space 103 is compressed and discharged to the discharge space 104, and then passes through the circulation pipe 115a and the discharge pipe 115 and is discharged to the outside of the compressor 100.

Fig. 3 is a sectional view of a part of the constitution of a compressor according to an embodiment of the present invention. Fig. 4 is an enlarged view of a portion a of fig. 3. Fig. 5 is a cross-sectional view of a liner and cylinder of a compressor in accordance with an embodiment of the present invention.

Fig. 7 is a graph showing the thermal deformation amount of the inner diameter of the bushing based on the thickness of the push-in belt according to an embodiment of the present invention. Fig. 8 is a graph showing the linear expansion coefficient of a bushing based on the thickness of a push belt according to an embodiment of the present invention.

The compressor 100 according to an embodiment of the present invention may include the cylinder tube 140, the piston 150, and the bush (bush) 200, but some of the components may be omitted, and additional components may not be excluded.

The compressor 100 may include a cylinder 140. The cylinder 140 may be formed in a cylindrical shape. The cylinder 140 may be formed in a cylindrical shape with its front and rear opened. The cylinder 140 may be formed to extend in the axial direction. The cylinder 140 may be fixed to the frame 120. The cylinder 140 may be formed with a gas inflow port 142. A piston 150 may be disposed within the cylinder 140. A liner 200 may be disposed inside the cylinder 140. A bushing 200 may be disposed between the cylinder 140 and the piston 150. The bushing 200 may be press-fitted to the inner side surface of the cylinder tube 140. The inner diameter of the cylinder 140 may be smaller than the outer diameter of the bushing 200 before the bushing 200 is press-fitted to the cylinder 140.

The compressor 100 may include a piston 150. The piston 150 may be disposed in the cylinder 140. The piston 150 may be disposed within the cylinder 140. The outer side of the piston 150 may be spaced apart from the inner side of the cylinder 140. A gap may be formed between the outer side surface of the piston 150 and the inner side surface of the cylinder tube 140. Here, the gap between the inner side surface of the cylinder 140 and the outer side surface of the piston 150 may be a difference between the size of the inner diameter of the cylinder 140 and the size of the outer diameter of the piston 150.

The compressor 100 may include a liner 200. The liner 200 may be disposed within the cylinder 140. The bushing 200 may be disposed between the cylinder 140 and the piston 150. The liner 200 may be coupled to an inner side surface of the cylinder tube 140. The bushing 200 may be press-fitted to the inner side surface of the cylinder tube 140. The outer diameter of the bush 200 may be sized to be larger than the inner diameter of the cylinder 140 before the bush 200 is press-coupled to the cylinder 140. Thus, in the case where the bush 200 is press-coupled to the inner side surface of the cylinder 140, a press-in belt 210 may be formed between the bush 200 and the cylinder 140.

The piston 150 and the bush 200 may be formed of materials different from each other. For example, the piston 150 may be formed of an aluminum material, and the bush 200 may be formed of a cast iron material, so that wear resistance between the piston 150 and the bush 200 can be improved. In this case, since the linear expansion coefficient of the piston 150 is greater than that of the liner 200, the gap d between the outer side surface of the piston 150 and the inner side surface of the liner 200 may be reduced in the case where the temperature rises due to the reciprocation of the piston 150 in the axial direction.

In an embodiment of the present invention, since the push belt 210 is formed between the liner 200 and the cylinder tube 140, the compressor 100 may satisfy the following equation 1.

[ formula 1]

δ _T ＝δ _TD +δ _ED β

Here, δ _T May refer to the total deformation, δ, of the inner diameter of the bushing 200 _TD May refer to the amount of thermal deformation, delta, of the bushing 200 _ED May refer to the amount of elastic deformation of the bushing 200, and β may refer to the elastic deformation coefficient of the bushing 200.

That is, by increasing the elastic deformation amount of the bush 200 and the elastic deformation coefficient of the bush 200, the total deformation amount of the inner diameter of the bush 200 is increased, so that the clearance d between the piston 150 and the bush 200 can be prevented from being reduced.

Here, the elastic deformation coefficient β of the bushing 200 may satisfy the following equation 2.

[ formula 2]

Here, β may refer to an elastic deformation coefficient, Y, of the bushing 200 _c May refer to the yield strength, Y, of the cylinder 140 _b May refer to the yield strength, C, of the bushing 200 _c May refer to the linear expansion coefficient, C, of the cylinder 140 _b May refer to the linear expansion coefficient of the liner 200.

That is, the elastic deformation coefficient of the liner 200 may be inversely proportional to the yield strength of the cylinder 140, and may be proportional to the yield strength of the liner 200, and may be proportional to the linear expansion coefficient of the cylinder 140, and may be proportional to the linear expansion coefficient of the liner 200.

In other words, the yield strength of the cylinder tube 140 is reduced, the yield strength of the liner 200 is increased, the linear expansion coefficient of the cylinder tube 140 is increased, and the linear expansion coefficient of the liner 200 is increased, whereby the gap d between the piston 150 and the liner 200 can be prevented from being reduced even during operation at a high temperature of 100 ℃. Accordingly, collision between the piston 150 and the cylinder tube 140 can be prevented.

For example, the coefficient of linear expansion of the cylinder 140 may be greater than the coefficient of linear expansion of the liner 200. Additionally, the yield strength of the liner 200 may be greater than the yield strength of the cylinder 140.

The cylinder 140 and the bush 200 may be formed of materials different from each other. For example, the liner 200 may be formed of cast iron material, and the cylinder 140 may be formed of aluminum material, so that wear resistance between the liner 200 and the cylinder 140 can be improved. In this case, the cylinder 140 may be made of an al—mg—si aluminum alloy material. Accordingly, even during operation at a high temperature of 100 ℃ or higher, the gap d between the bush 200 and the piston 150 can be maintained at a predetermined distance or longer, and collision between the bush 200 and the piston 150 can be prevented.

In case that the gap d between the liner 200 and the piston 150 is too small, collision may occur between these components, and in case that the gap d between the liner 200 and the piston 150 is too large, compression efficiency of the compressor 100 may be lowered. Referring to fig. 6, the gap d between the bushing 200 and the piston 150 may be 10 μm at normal temperature. The difference between the size of the inner diameter of the bush 200 and the size of the outer diameter of the piston 150, that is, the gap d between the bush 200 and the piston 150 may be 5 μm or more at a temperature of 100 ℃. This can not only improve the compression efficiency of the compressor 100, but also prevent collision between the liner 200 and the piston 150.

Before the bush 200 is press-fitted into the cylinder tube 140, if the difference between the outer diameter of the bush 200 and the inner diameter of the cylinder tube 140, that is, the thickness of the press-fit belt 210 is small, the thermal deformation amount of the inner diameter of the bush 200 may be reduced. In contrast, in the case where the thickness of the push belt 210 is large, the plastic deformation region becomes large, and thus the thermal deformation amount of the inner diameter of the bush 200 may increase.

Specifically, referring to fig. 7 and 8, in the case where the thickness of the press-fit belt 210 is 120 μm, it can be confirmed that: the linear expansion coefficient of the liner 200 rises to the vicinity of 17.5, and the thermal deformation amount of the liner 200 is between 30 μm and 35 μm. In addition, in the case where the thickness of the press-fit belt 210 was 80 μm, it was confirmed that: the linear expansion coefficient of the liner 200 increases to between 18 and 19, and the thermal deformation amount of the liner 200 is between 30 μm and 35 μm. In contrast, in the case where the thickness of the press-fit belt 210 is less than 80 μm, it is confirmed that the thermal deformation amount of the bushing 200 is reduced to between 20 μm and 25 μm.

That is, the difference between the size of the outer diameter of the bush 200 and the size of the inner diameter of the cylinder 140, that is, the thickness of the press-fit belt 210 may be between 80 μm and 120 μm before the bush 200 is press-fitted to the cylinder 140. Preferably, the difference between the size of the outer diameter of the bush 200 and the size of the inner diameter of the cylinder 140 may be between 80 μm and 90 μm before the bush 200 is press-coupled to the cylinder 140. Thus, by increasing the total deformation amount of the inner diameter of the bush 200, the clearance d between the piston 150 and the bush 200 can be prevented from being reduced.

Any embodiments or other embodiments of the specification described above are not necessarily exclusive or distinguishing between each other. The individual constituent elements or functions of any of the embodiments or other embodiments of the present invention described above may be combined or combined.

For example, this means that the a-configuration illustrated in a particular embodiment and/or drawing and the B-configuration illustrated in other embodiments and/or drawing may be combined. That is, even if the combination between the components is not directly described, unless the combination is not explicitly indicated, it means that the combination is possible.

The foregoing detailed description is, therefore, not to be taken in a limiting sense, but is to be understood as being exemplary in all respects. The scope of the invention should be determined by reasonable interpretation of the appended claims, and all change which comes within the equivalent scope of the invention should be included in the scope of the invention.

Claims

1. A gas lubrication type compressor for compressing and discharging a refrigerant sucked into a cylinder tube, comprising:

a cylinder tube of a cylindrical shape;

a piston disposed inside the cylinder tube and reciprocating in an axial direction; and

A bushing press-fitted to an inner side surface of the cylinder tube,

the difference between the size of the outer diameter of the bush and the size of the inner diameter of the cylinder barrel is 80-120 μm before the bush is press-bonded to the cylinder barrel,

a press-in band is formed between the bush and the cylinder tube,

the compressor satisfies the following formula,

[ formula 1]

δ _T ＝δ _TD +δ _ED β

Wherein delta _T Refers to the total deformation of the inner diameter of the bushing, delta _TD Refers to the thermal deformation amount, delta of the bushing _ED Refers to the elastic deformation amount of the bushing, beta refers to the elastic deformation coefficient of the bushing,

at a temperature of 100 ℃, the difference between the size of the inner diameter of the bush and the size of the outer diameter of the piston is 5 μm or more.

2. The compressor of claim 1, wherein,

the difference between the size of the outer diameter of the bush and the size of the inner diameter of the cylinder barrel is 80-90 μm before the bush is press-bonded to the cylinder barrel.

3. The compressor of claim 1, wherein,

the linear expansion coefficient of the cylinder tube is larger than that of the bushing.

4. The compressor of claim 1, wherein,

the bushing has a yield strength greater than the cylinder.

5. The compressor of claim 1, wherein,

the piston and the bush are formed of materials different from each other.

6. The compressor of claim 1, wherein,

the bushing is formed of cast iron material, and the piston is formed of aluminum material.

7. The compressor of claim 1, wherein,

the cylinder is formed of an aluminum material, and the bush is formed of a cast iron material.

8. The compressor of claim 7, wherein,

the cylinder is formed of an Al-Mg-Si series aluminum alloy.