CN212079573U

CN212079573U - Linear compressor

Info

Publication number: CN212079573U
Application number: CN202020145806.0U
Authority: CN
Inventors: 全宇宙; 崔基喆; 金泳泌
Original assignee: LG Electronics Inc
Current assignee: LG Electronics Inc
Priority date: 2019-01-29
Filing date: 2020-01-22
Publication date: 2020-12-04
Anticipated expiration: 2030-01-22
Also published as: KR102653977B1; KR20200093981A

Abstract

The utility model relates to a linear compressor. The utility model discloses a linear compressor of embodiment includes: a cylinder barrel formed with a compression space; and a piston inserted into the cylinder and reciprocating in a front-rear direction, the cylinder including: a first portion forming an outer peripheral surface of the cylinder; a second portion provided inside the first portion and forming an inner peripheral surface of the cylinder; and a groove formed in the cylinder barrel recess, a space being formed between the first portion and the second portion. This facilitates deformation of the cylinder tube, and increases the clearance formed between the outer peripheral surface of the piston and the inner peripheral surface of the cylinder tube.

Description

Linear compressor

Technical Field

The utility model relates to a linear compressor.

Background

Generally, a Compressor (Compressor) is widely used in household electric appliances or the entire industry as a mechanical device that receives power from a power generation device such as a motor or a turbine and increases pressure by compressing air, refrigerant, or other various working gases.

Such a compressor can be roughly classified into a Reciprocating compressor (Reciprocating compressor) which forms a compression space for sucking and discharging a working gas between a Piston (Piston) and a Cylinder (Cylinder) and compresses a refrigerant by linearly Reciprocating the Piston inside the Cylinder, a Rotary compressor (Rotary compressor) which forms a compression space for sucking and discharging a working gas between an eccentrically rotating Roller (Roller) and the Cylinder and compresses a refrigerant when the Roller eccentrically rotates along an inner wall of the Cylinder, and a Scroll compressor (Scroll compressor) which forms a compression space for sucking and discharging a working gas between a Orbiting Scroll (Orbiting Scroll) and a Fixed Scroll (Fixed Scroll) and compresses a refrigerant when the Orbiting Scroll rotates along the Fixed Scroll.

Recently, among the reciprocating compressors, a linear compressor having a simple structure, in which a piston is directly connected to a driving motor performing a reciprocating linear motion, thereby preventing a mechanical loss due to motion conversion and improving compression efficiency, has been extensively developed.

As for the existing linear compressor, the present applicant has already filed a patent (hereinafter, referred to as existing document) and obtained an authorization.

Publication No. (publication date): korean laid-open patent No. 10-2016-

The invention name is as follows: linear compressor

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a through make the bearing work between linear compressor's cylinder and piston easily, reduce the linear compressor of the friction between piston and the cylinder.

In addition, an object of the present invention is to provide a linear compressor in which a deformable portion is provided in a cylinder and a gap between the deformable portion and a piston can be increased by a pressure acting between the piston and the cylinder.

In particular, an object of the present invention is to provide a linear compressor in which a recess is formed in a rear portion of a cylinder tube into which a piston is inserted, thereby providing a space in which at least a part of the rear portion can be deformed.

The utility model discloses a linear compressor's cylinder includes the recess that caves in to the place ahead from the rear portion of cylinder, makes the cylinder warp easily from this to can increase the clearance that forms between the outer peripheral face of piston and the inner peripheral surface of cylinder.

The groove may be formed in a ring shape between the first portion and the second portion constituting the rear portion of the cylinder tube.

The groove may be formed such that its radial width is constant, or decreases toward the front.

The utility model discloses a linear compressor of embodiment includes: a cylinder barrel formed with a compression space; and a piston inserted into the cylinder and reciprocating in a front-rear direction, the cylinder including: a first portion forming an outer peripheral surface of the cylinder; a second portion provided inside the first portion and forming an inner peripheral surface of the cylinder; and a groove formed in the cylinder barrel recess, a space being formed between the first portion and the second portion.

The compression space is formed in a front portion of the cylinder tube, and the groove is recessed in a rear portion of the cylinder tube.

The first portion may be configured to surround the second portion, and the groove may have a ring shape.

The cylinder may include a hollow cylinder-shaped cylinder body, and the first portion and the second portion may constitute a rear portion of the cylinder body.

The second portion may be subjected to cantilever deformation, the cantilever deformation being deformation in which a rear end portion of the second portion is flared centering on a front end portion.

The second portion may be constructed of aluminum or steel.

The piston may reciprocate in the axial direction inside the cylinder tube, and a radial thickness of the second portion may be constant in the front-rear direction.

The ratio of the radial thickness t1 of the second portion to the inner diameter do of the cylinder barrel may be in the range of 0.2 to 0.4.

The ratio of the axial length l1 of the second portion to the axial length lo of the cylinder barrel may be in the range of 0.3 to 0.5.

The radial width of the groove may decrease toward the front.

The piston is axially reciprocable within the bore, and the radial thickness t4 of the front end of the second portion may be greater than the radial thickness t3 of the rear end.

The ratio of the radial thickness t3 of the rear end portion of the second section of the cylinder tube to the inner diameter of the cylinder tube may be in the range of 0.1 to 0.2, and the ratio of the radial thickness t4 of the front end portion of the second section of the cylinder tube to the inner diameter of the cylinder tube may be in the range of 0.2 to 0.4.

According to the utility model discloses an embodiment makes the bearing work between linear compressor's cylinder and piston easily, can reduce the friction between piston and the cylinder from this.

Further, the cylinder tube is provided with a deformable portion, and the clearance between the portion and the piston can be increased by a pressure acting between the piston and the cylinder tube.

In particular, a groove is formed in a rear portion of the cylinder tube into which the piston is inserted, whereby a space for deforming at least a part of the rear portion can be provided.

Drawings

Fig. 1 is an exploded perspective view of a cylinder and a piston according to an embodiment of the present invention.

Fig. 2 is a cross-sectional view showing a state in which the piston according to the embodiment of the present invention is inserted into the cylinder.

Fig. 3 is a perspective view showing the structure of a cylinder tube according to a first embodiment of the present invention.

Fig. 4 is a sectional view taken along line IV-IV' of fig. 3.

Fig. 5 is a sectional view showing a state in which the size of the groove changes when the piston reciprocates according to the first embodiment of the present invention.

Fig. 6 is a sectional view taken along line VI-VI' of fig. 5.

Fig. 7A is an experimental graph showing the minimum gap according to the ratio of the radial thickness of the second portion to the inner diameter of the cylinder tube according to the first embodiment of the present invention.

Fig. 7B is an experimental graph showing the minimum clearance according to the ratio of the axial length of the second portion to the axial length of the cylinder tube according to the first embodiment of the present invention.

Fig. 8 is a sectional view showing the structure of a cylinder tube according to a second embodiment of the present invention.

Detailed Description

Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. However, the idea of the present invention is not limited to the mentioned embodiments, and other embodiments can be easily proposed within the scope of the same idea for a person having ordinary skill in the art to understand the idea of the present invention.

Fig. 1 is an exploded perspective view of a cylinder and a piston according to an embodiment of the present invention, and fig. 2 is a sectional view showing a state in which the piston according to the embodiment of the present invention is inserted into the cylinder.

Referring to fig. 1 and 2, a linear compressor according to an embodiment of the present invention includes a cylinder 100 forming a compression space and a piston 150 reciprocating in an axial direction inside the cylinder 100.

A compression space P in which the piston 150 compresses the refrigerant is formed inside the cylinder tube 100. A suction port 152a through which refrigerant flows into the compression space P is formed in the front surface 152 of the piston 150, and a suction valve 160 selectively opening the suction port 152a is provided in front of the suction port 152 a. A valve fastening hole 165 to which the fastening member 153 is coupled is formed at a substantially central portion of the suction valve 160.

A discharge valve 140 movable to open or close the compression space P is provided in front of the compression space P to selectively discharge the refrigerant discharged from the compression space P.

A direction is defined. "axial" refers to the direction of reciprocation of the piston 150, i.e., lateral in FIG. 2. In the "axial direction", a direction from the suction valve 160 toward the discharge valve 140, that is, a flow direction of the refrigerant is defined as "forward", and a direction opposite thereto is defined as "backward".

The cylinder tube 100 includes a substantially cylindrical cylinder tube body 110 and a cylinder tube flange portion 120 extending radially outward from a front portion of the cylinder tube body 110. The cylinder flange portion 120 may be coupled to a frame (not shown).

A recess 130 is formed in the cylinder main body 110, and at least a part of the compressed refrigerant discharged when the discharge valve 140 is opened flows through the recess 130. The recess 130 may be concavely formed in a circumferential direction of the cylinder main body 110 and have a ring shape. The refrigerant flowing into the recess 130 can flow into the inner circumferential surface of the cylinder tube body 110 and function as a gas bearing.

The recess 130 may be provided in plurality at intervals in the axial direction. In detail, the recess 130 includes a first recess 131 formed in a front portion of the cylinder main body 110 and a second recess 133 formed to be spaced apart from the first recess 131 toward a rear side.

A filter 145 may be disposed in the recess 130. The filter parts 145 may be disposed in the first recess 131 and the second recess 133, respectively. As an example, the filter part 145 includes a wire filter, and the wire filter may be disposed to be wound on the first groove 131 and the second groove 133 a plurality of times.

The piston 130 includes a piston main body 151 having a substantially cylindrical shape, and a piston flange portion 155 extending in a radial direction from a rear portion of the piston main body 151. The piston main body 151 is capable of reciprocating inside the cylinder main body 110, and the piston flange portion 155 is capable of reciprocating outside the cylinder main body 110.

The piston flange portion 155 may include a piston fastening hole 157 to which a prescribed fastening member is coupled. The fastening member may penetrate the piston fastening hole 157 and be coupled to a frame (not shown) provided with a magnet.

The cylinder body 110 includes a cylinder nozzle 135, and the cylinder nozzle 135 is formed recessed in the recessed portion 130, and causes the refrigerant to flow into the inner circumferential surface of the cylinder body 110. That is, the cylinder nozzle 135 connects the recess 130 and the inner peripheral surface 111 of the cylinder main body 110.

Further, the cylinder nozzle 135 may be provided in plurality at intervals in the circumferential direction. The plurality of nozzles 135 have the same structure, and the refrigerant filtered of the foreign substances through the filtering part 145 may flow to the plurality of nozzles 135.

Fig. 3 is a perspective view showing a structure of a cylinder tube according to a first embodiment of the present invention, fig. 4 is a sectional view taken along line IV-IV 'of fig. 3, fig. 5 is a sectional view showing a state in which a size of a groove changes when a piston reciprocates according to the first embodiment of the present invention, and fig. 6 is a sectional view taken along line VI-VI' of fig. 5.

Referring to fig. 3 and 4, a cylinder 100 according to a first embodiment of the present invention includes a cylinder main body 110 having a hollow cylindrical shape, and a cylinder flange portion 120 radially extending from an outer peripheral surface of a front portion of the cylinder main body 110.

The piston 150 may be inserted into the cylinder body 110, and the inner circumferential surface 111 of the cylinder body 110 may be disposed to be opposite to the outer circumferential surface of the piston 150.

The cylinder 100 is formed to be open at the front and rear ends. Specifically, a front opening 110a that opens is formed at the front end of the cylinder main body 110. The front opening 110a may have a circular shape.

A discharge valve 140 may be provided at the front opening portion 110 a. And, a compression space P may be formed between the discharge valve 140 and the suction valve 160 coupled with the piston 150.

A rear opening 110b that opens is formed at a rear end of the cylinder main body 110. The rear opening 110b may have a circular shape. The piston main body 151 is inserted into the cylinder main body 110 through the rear opening 110 b.

The cylinder 100 may include a variable mechanism that can be deformed to prevent the cylinder from contacting the surface of the piston 150 when the piston 150 reciprocates. The variable mechanism may include a groove 115 formed by cutting at least a portion of the cylinder 110.

In detail, the piston 150 may move eccentrically with respect to the inner center of the cylinder tube 100 due to the gravity and a side force (side force) acting in a radial direction when the piston 150 acts in the front-rear direction. In this case, friction may occur between the piston 150 and the cylinder 100, and thus there is a risk that the piston 150 or the cylinder 100 may be damaged. In particular, when the force for decentering the piston 150 is larger than the pressure of the refrigerant functioning as the gas bearing, the friction is larger.

In order to prevent this, a deformable portion is provided in the cylinder tube 100, and when the piston 150 approaches the cylinder tube 100 during the eccentric movement of the piston 150, at least a part of the cylinder tube 100 is deformed by the action of the gas bearing, thereby maintaining a gap (gap) between the inner circumferential surface of the cylinder tube 100 and the outer circumferential surface of the piston 150.

The cylinder main body 110 includes a cylinder rear portion 113.

In detail, the cylinder rear portion 113 includes a first portion 114 forming an outer peripheral surface, a second portion 116 spaced inward of the first portion 114, and a groove 115 forming a space between the first and

second portions

114, 116.

The first portion 114 has a cylindrical shape to form the outer peripheral surface of the cylinder main body 110. Also, the second portion 116 may have a cylindrical shape to form the inner circumferential surface 111 of the cylinder tube body 110. The first portion 114 may be configured to surround the second portion 116.

The groove 115 may be formed between the first portion 114 and the second portion 116, and has a ring shape (annular shape). From a different point of view, the rear face portion 112 of the cylinder tube body 110 may have a ring shape through the rear opening portion 110b, and the groove 115 may be formed in a ring shape recessed toward the front from the rear face portion 112.

The groove 115 is formed, and therefore at least a part of the rear portion of the cylinder main body 110 is cut, which means that the thickness of the cylinder main body 110 becomes thin. Therefore, when the high-pressure refrigerant functions as a bearing between the piston 150 and the cylinder tube 100, the second portion 116 may be deformed. That is, it can be understood that the groove 115 is a space portion capable of deforming the second portion 116.

The thickness of the rear end of the second portion 116 forms a first thickness t1 and the thickness of the front end of the second portion 116 forms a second thickness t 2. Also, the value of the first thickness t1 and the value of the second thickness t2 may be the same. I.e. the radial thickness of the second portion 116 is constant.

The axial length of the second portion 116, i.e., the length in the front-rear direction, is formed to a prescribed length l 1. According to such a structure of the second portion 116, the cross section of the second portion 116 may be a rectangular shape. Also, the cross-section of the first portion 114 may be rectangular in shape.

The groove 115 may be formed such that its radial width W1 is constant. However, the width W1 of the groove 115 may vary when the second portion 116 is deformed in correspondence with the movement of the piston 115.

In detail, the piston 150 may be eccentric with respect to the inner center line Co of the cylinder tube 100 when actuated. For example, as shown in fig. 5, the piston 150 may be eccentric toward the lower portion side of the cylinder rear surface portion 113.

At this time, the outer surface of the piston 150 may contact the inner circumferential surface of the cylinder 100. Such contact may occur when the pressure based on the eccentricity of the piston 150 reaches above the gas bearing pressure.

When such a possibility of contact occurs, the pressure of the refrigerant acting as the gas bearing acts on the second portion 116, and the second portion 116 is deformed so as to expand outward in the radial direction by a predetermined amount Δ d. For example, the rear end portion of the second portion 116 may be cantilevered around the front end portion of the second portion 116.

Furthermore, the deformation of the second portion 116 may be achieved by the groove 115, the radial width of the groove 115 being reduced as the second portion 116 is deformed.

That is, as shown in fig. 6, the width of the groove 115 may be changed from a first width W1 when the second portion 116 is undeformed to a second width W2 based on the deformation of the second portion 116. Of course, the second width W2 may be less than the first width W1.

According to a variation of the groove 115, the ring-shaped groove 115 may form an ellipse having a vertical radial major axis and a horizontal radial minor axis. At this time, a portion of the groove 115 maintaining the first width W1 forms a first groove 115', and another portion of the groove 115 forming the second width W1 forms a second groove 115 ″. The first groove 115' and the second groove 115 ″ may communicate with each other.

The second portion 116 may be formed of a metal member having a prescribed elasticity so that the second portion 116 is easily deformed. As an example, the metal member may include aluminum or steel.

The second portion 116 and the first portion 114 may be formed as one piece. Also, the first portion 114 and the second portion 116 may be formed integrally with the cylinder tube body 110.

Fig. 7A is an experimental graph showing the minimum gap according to the ratio of the radial thickness of the second portion to the inner diameter of the cylinder tube according to the first embodiment of the present invention, and fig. 7B is an experimental graph showing the minimum gap according to the ratio of the axial length of the second portion to the axial length of the cylinder tube according to the first embodiment of the present invention.

Referring to fig. 7A, in a state where the ratio of the radial thickness t1 of the second portion 116 to the inner diameter do of the cylinder 100 is made different according to the first embodiment of the present invention, when the piston 150 reciprocates, a minimum clearance (hereinafter, referred to as a bearing clearance) between the outer peripheral surface of the piston main body 151 and the inner peripheral surface 115 of the cylinder main body 110 may be changed.

If the bearing gap is too small, the possibility of contact between the piston 150 and the cylinder 100 is high. In the environment where the linear compressor is operated, the bearing gap needs to be maintained at a reference gap (0.18mm) or more, so that the contact possibility of the piston 150 and the cylinder tube 100 becomes low.

The bearing gap can be set to a ratio t1/do equal to or greater than a reference gap in a range of 0.2 to 0.4. Therefore, the radial thickness of the second portion 116 and the inner diameter of the cylinder tube 100 of the first embodiment of the present invention can be designed within the above ratio range.

Referring to fig. 7B, in a state where the ratio of the axial length l1 of the second portion 116 to the axial length lo of the cylinder 100 of the first embodiment of the present invention is made different, when the piston 150 reciprocates, a minimum clearance (hereinafter, referred to as a bearing clearance) between the outer peripheral surface of the piston main body 151 and the inner peripheral surface 115 of the cylinder main body 110 may be changed.

The bearing clearance can be set to a ratio l1/lo of 0.3 to 0.5 which is equal to or larger than a reference clearance (0.18 mm). Therefore, the axial length l1 of the second portion 116 of the first embodiment relative to the axial length lo of the cylinder tube 100 can be designed within the above ratio range.

Referring to fig. 8, a cylinder tube 100a according to a second embodiment of the present invention includes a rear portion 113a having a deformable variable mechanism.

The rear portion 113a of the cylinder barrel body 110 includes a first portion 114a forming an outer peripheral surface, a second portion 116a spaced inward of the first portion 114a, and a groove 115a forming a space between the first portion 114a and the second portion 116 a.

The first portion 114a has a cylindrical shape to form the outer peripheral surface of the cylinder tube body 110. The second portion 116a forms the inner peripheral surface portion 111 of the cylinder tube body 110 and has an inclined surface. The first portion 114a may be configured to surround the second portion 116 a.

The groove 115a is formed between the first portion 114a and the second portion 116a, and has a ring shape (annular shape). From another point of view, the rear face portion 112 of the cylinder tube body 110 may have a ring shape by the rear opening portion 110b, and the groove 115a may be formed to be recessed toward the front from the rear face portion 112.

At least a part of the rear portion of the cylinder main body 110 is recessed by the groove 115, which means that the thickness of the cylinder main body 110 becomes thin. Therefore, when the high-pressure refrigerant acts as a bearing between the piston 150 and the cylinder tube 100, the second portion 116a may be deformed. That is, it can be understood that the groove 115a is a space portion capable of deforming the second portion 116 a.

The thickness of the rear end of the second portion 116a forms a first thickness t3, and the thickness of the front end of the second portion 116a forms a second thickness t 4. Also, the second thickness t4 may be greater than the first thickness t 3.

According to this structure, the groove 115a may have a shape in which a radial width thereof becomes smaller toward the front. As an example, as shown in fig. 8, the cross-sectional shape of the groove 115a may be a triangle.

The axial length, i.e., the front-rear direction length, of the second portion 116a is formed at a prescribed length l 2. According to such a structure of the second portion 116a, the cross section t of the second portion 116a may be a trapezoidal shape. Also, the cross-section of the first portion 114a may be rectangular in shape.

If the possibility of contact between the piston 150 and the cylinder tube 110a occurs, the pressure of the refrigerant acting as a gas bearing acts on the second portion 116a, and the second portion 116a deforms to expand by a predetermined amount Δ d. For example, the rear end portion of the second portion 116a may be cantilevered around the front end portion of the second portion 116 a.

Also, the deformation of the second portion 116a may be achieved by the groove 115, and as the second portion 116a is deformed, the radial width of the groove 115 becomes smaller.

The ratio of the radial thickness t3 of the rear end portion of the second portion 116a of the second embodiment to the inner diameter of the cylinder 100 may be 0.1 to 0.2. The ratio of the radial thickness t4 of the tip end portion of the second portion 116a to the inner diameter of the cylinder tube 100 may be 0.2 to 0.4. In this case, the bearing gap may be formed to be 0.18mm or more of the reference gap.

On the other hand, the ratio of the axial length of the second portion 116a to the axial length of the cylinder tube 100 may be in the range of 0.3 to 0.5. In this case, the bearing gap may be formed to be the reference gap (0.18mm) or more.

As described above, by including the variable mechanism provided in the cylinder tube in a deformable manner, the bearing gap between the outer circumferential surface of the piston and the inner circumferential surface of the cylinder tube can be maintained at the reference gap or more. Therefore, the contact of the piston 150 with the cylinder 100 can be prevented.

Next, another embodiment is proposed.

In the above first and second embodiments, the case where the gas bearing using the high-pressure refrigerant is applied to suspend the piston inside the cylinder tube is explained.

However, the present invention is not limited to this, and an oil bearing that supplies oil to the inside of the cylinder and forms an oil film between the piston and the cylinder to function as a bearing may be applied.

Claims

1. A linear compressor, comprising:

a cylinder barrel formed with a compression space; and

a piston inserted into the cylinder and reciprocating in a front-rear direction,

the cylinder barrel includes:

a first portion forming an outer peripheral surface of the cylinder;

a second portion provided inside the first portion and forming an inner peripheral surface of the cylinder; and

a groove formed in the cylinder barrel recess, forming a space between the first portion and the second portion.

2. The linear compressor of claim 1,

the compression space is formed in a front portion of the cylinder,

the groove is recessed behind the cylinder barrel.

3. The linear compressor of claim 1,

the first portion is configured to surround the second portion,

the groove has a ring shape.

4. The linear compressor of claim 1,

the cylinder includes a cylinder body having a hollow cylindrical shape,

the first portion and the second portion constitute a rear portion of the cylinder tube main body.

5. The linear compressor of claim 4,

the second portion is subjected to cantilever deformation, which is deformation in which a rear end portion of the second portion is flared with a front end portion as a center.

6. The linear compressor of claim 1,

the second portion is constructed of aluminum or steel.

7. The linear compressor of claim 1,

the piston reciprocates in the axial direction inside the cylinder,

the radial thickness of the second portion is constant in the front-rear direction.

8. The linear compressor of claim 7,

the ratio of the radial thickness (t1) of the second portion to the inner diameter (do) of the cylinder barrel is 0.2 to 0.4,

the ratio of the axial length (l1) of the second portion to the axial length (lo) of the cylinder barrel is 0.3 to 0.5.

9. The linear compressor of claim 2,

the radial width of the groove decreases towards the front,

the radial thickness (t4) of the front end portion of the second portion is greater than the radial thickness (t3) of the rear end portion.

10. The linear compressor of claim 9,

the ratio of the radial thickness (t3) of the rear end portion of the second portion to the inner diameter of the cylinder tube is 0.1 to 0.2,

the ratio of the radial thickness (t4) of the front end portion of the second portion to the inner diameter of the cylinder tube is 0.2-0.4.