WO2008082122A2

WO2008082122A2 - Linear compressor

Info

Publication number: WO2008082122A2
Application number: PCT/KR2007/006776
Authority: WO
Inventors: Sun Yong Choi
Original assignee: Lg Electronics Inc.
Priority date: 2006-12-29
Filing date: 2007-12-24
Publication date: 2008-07-10
Also published as: WO2008082122A3

Abstract

A linear compressor is disclosed. More particularly, a linear compressor, which can stably supply oil into a cylinder and achieve high system reliability, is disclosed. The linear compressor comprises an oil supply mechanism to supply oil to the piston of the compressor by use of power generated as the compressor body (140) vibrates in a reciprocating movement direction of the piston. The oil suction port (132) of the oil supply mechanism is formed in substantially the same direction as the vibrating direction of the body (140).

Description

LINEAR COMPRESSOR

Technical Field

[1] The present invention relates to a linear compressor, and more particularly, to a linear compressor, which can stably supply oil into a cylinder, thereby achieving high system reliability. Background Art

[2] Generally, a linear compressor is an appliance to suction and compress a refrigerant and discharge the compressed refrigerant as a piston is rectilinearly reciprocally moved within a cylinder by use of a rectilinear drive force of a linear motor.

[3] FIG. 1 is a sectional view illustrating a conventional linear compressor, and FIG. 2 is a schematic diagram illustrating only a separated body part of the linear compressor.

[4] The conventional linear compressor shown in FIG. 1 includes a cylinder block 10 and a back cover 12, which are received in a case 2.

[5] The cylinder block 10 includes a cylinder 14, into which a refrigerant, having passed through a refrigerant suction pipe 4 provided at the case 2, is supplied. The cylinder 14 receives a piston 16 therein. The piston 16 is used to compress the refrigerant within the cylinder 14 while being rectilinearly reciprocally moved in the cylinder 14. Provided at the outside of the cylinder 14 is a discharge mechanism 18. The discharge mechanism 18 includes a discharge valve 18 to discharge the compressed refrigerant 14 within the cylinder 14 into a discharge pipe 6 provided at the case 2.

[6] The piston 16 is connected with a linear motor 20 located between the cylinder block 10 and the back cover 12 such that a rectilinear reciprocating drive force of the linear motor 20 is transmitted to the piston 16. The linear motor 20 basically includes a stator, and a mover to perform a rectilinear reciprocating movement by electromag- netically interacting with the stator.

[7] The stator includes an inner core 21 press-fitted around the cylinder 14, a ring- shaped outer core 22 arranged around the inner core 21 by a predetermined interval, and a coil 23 installed to the outer core 22 to create a magnetic field.

[8] The mover includes a magnet 25 located between the inner core 21 and the outer core 22, and a magnet frame 26 installed between the magnet 25 and the piston 16 and connected with both the magnet 25 and the piston 16, to transmit the rectilinear drive force of the linear motor 20 to the piston 16. [9] Meanwhile, as shown in FIG. 2, when considering only a body 40, which is located within the case 2 and assembled with compressor's drive elements, separately from the linear compressor, a damper 42 is provided to support the body 40 within the case 2.

[10] In addition, in order to alleviate the risk of frictional wear between the cylinder 14 and the piston 16, an oil pipe 32 is provided to supply oil to the piston 16. The oil pipe 32 is formed, at a distal end thereof, with an oil suction port 30, to svction oil stored in the case 2.

[11] Now, the operation of the conventional linear compressor having the above described configuration will be described.

[12] If electric power is applied to the coil 23 of the linear motor 20, a magnetic field is created between the stator and the mover, thereby causing the magnet 25 to be rec- tilinearly reciprocally moved. The rectilinear reciprocating movement of the magnet 25 is transmitted to the piston 16 through the magnet frame 26. As a result, the piston 16 is rectilinearly reciprocally moved within the cylinder 14.

[13] Simultaneously with the rectilinear reciprocating movement of the piston 16, the discharge valve 18 and a suction valve 17 are repeatedly opened and closed. With the operations of the piston 16 and the valves 18 and 17, a refrigerant is suctioned into the cylinder 14 by way of the case 2, back cover 12, and piston 16. After being suctioned into the cylinder 14, the refrigerant is compressed to a high pressure refrigerant within a compressing chamber C defined in the cylinder 14 by operation of the piston 16. The compressed refrigerant within the compressing chamber C of the cylinder 14 is discharged to the outside of the case 2 through the discharge mechanism 18.

[14] The above described compression and discharge procedure of the refrigerant is sequentially repeated so long as the linear motor 20 is operated.

[15] In this case, as described above, in order to alleviate a frictional force between the cylinder 14 and the piston 16, the oil is suctioned through the oil suction port 30, and is supplied to the piston 16 through the oil pipe 32. Disclosure of Invention Technical Problem

[16] However, in the case where the above described linear compressor is used in, for example, a refrigerator or air-conditioner, it may often need to perform a refrigerant recovery operation for recovering a refrigerant remained in an evaporator (not shown) During the refrigerant recovery operation, the linear compressor is operated in a locked state of a valve (not shown) provided at a refrigerant pipe (not shown), to prevent the refrigerant, having passed through the evaporator, from moving backward toward the evaporator.

[17] Wth the above described operation, the interior pressure of a suction pipe provided to receive the refrigerant transmitted from the evaporator is significantly lowered almost close to a vacuum pressure. Consequently, the case 2 of the linear compressor also has a very low interior pressure close to a vacuum pressure.

[18] The low interior pressure of the case 2 may hinder the efficient supply of oil. In the case where the supply of oil is axomplished based on a pressure difference caused by pumping, the low interior pressure of the case 2 storing the oil therein makes it difficult to arise the movement of the oil.

[19] For this reason, the refrigerant recovery operation of the linear compressor has a problem of a rapid reduction in the supply amount of oil. Moreover, if the supply amount of oil is reduced, it causes several problems, for example, the wear of constitute elements or the generation of particles due to a frictional force between the cylinder 14 and the piston 16, and results in deterioration in system reliability. Technical Solution

[20] The object of the present invention can be achieved by providing a linear compressor comprising: a case defining the outer appearance of the compressor; a body located in the case and assembled with compressor's drive elements; an oil supply mechanism to supply oil to a piston by use of power generated as the body vibrates in a reciprocating movement direction of the piston; and an oil suction port formed in substantially the same direction as a vibrating direction of the body, to suction oil.

[21] Preferably, the oil suction port is located in the oil stored in the case, and is formed at a distal end of a first oil pipe extending in substantially the same direction as the vibrating direction of the body.

[22] The oil supply mechanism may comprise: an oil piston to be reciprocally moved in substantially the same direction as the vibrating direction of the body; and an oil cylinder providing a space required for the reciprocating movement of the oil piston. Also, the oil supply mechanism may further comprise elastic members provided, respectively, to connect one end of the oil piston with one end of the oil cylinder and to connect the other end of the oil piston with the other end of the oil cylinder.

[23] Meanwhile, the first oil pipe may be connected with one end of the oil cylinder, and the linear compressor may further comprise: a second oil pipe to guide the oil from one end of the oil cylinder to the piston. [24] The linear compressor may further comprise: a first opening/closing valve and a second opening/closing valve provided, respectively, at junctions where the first oil pipe and the second oil pipe are connected with the oil cylinder, to intercept the movement of the oil.

[25] In another aspect of the present invention, provided herein is a linear compressor comprising: a piston to be reciprocally moved within a predetermined range; an oil pipe having an oil suction port formed in substantially the same direction as a reciprocating movement direction of the piston, the oil pipe creating a pressure difference in oil in the vicinity of the oil suction port under the influence of vibrations caused by the reciprocating movement of the piston; and an oil supply mechanism connected with the oil pipe and used to suction the oil from the oil suction port so as to supply the oil to the piston. Advantageous Effects

[26] A linear compressor according to the present invention has the following effects.

[27] Firstly, even if a case of the linear compressor has a very low interior pressure close to a vacuum pressure during the implementation of a refrigerant recovery operation, the linear compressor can assure a sufficient supply amount of oil.

[28] Secondly, the linear compressor can maintain a substantially uniform amount of oil to be supplied to a piston, thereby effectively reducing a frictional force between the piston and a cylinder.

[29] Thirdly, the linear compressor has an advantage of preventing any damage to constituent elements or generation of particles, resulting in high system reliability. Brief Description of the Drawings

[30] The accompanying drawings, which are included to provide a further understanding of the invention, illustrate embodiments of the invention and together with the description serve to explain the principle of the invention.

[31] In the drawings:

[32] FIG. 1 is a sectional view illustrating a conventional linear compressor.

[33] FIG. 2 is a schematic diagram illustrating only a separated body part of the linear compressor shown in FIG. 1.

[34] FIG. 3 is a schematic diagram illustrating an oil suction structure of a linear compressor according to the present invention.

[35] FIG. 4 is a configuration view schematically illustrating an oil supply mechanism of the linear compressor axording to the present invention. [36] FIG. 5 is a perspective view illustrating only an oil pipe and an oil suction port included in the linear compressor according to the present invention; and

[37] FIG. 6 is a perspective view illustrating only an oil pipe and an oil suction port included in the linear compressor according to another embodiment of the present invention. Mode for the Invention

[38] Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the axompanying drawings. However, the present invention is not limited to the embodiments described herein, and can be embodied to other various modifications and variations. The embodiments introduced herein are given to sufficiently transmit the scope of the present invention to those skilled in the art as well as for the sake of a perfect understanding of the present invention. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

[39] FIG. 3 is a schematic diagram illustrating an oil suction structure of a linear compressor according to the present invention. FIG. 4 is a configuration view schematically illustrating an oil supply mechanism of the linear compressor according to the present invention. FIG. 5 is a perspective view illustrating only an oil pipe and an oil suction port included in the linear compressor axording to the present invention. FIG. 6 is a perspective view illustrating only an oil pipe and an oil suction port included in the linear compressor according to another embodiment of the present invention.

[40] Referring to FIGs. 3 to 6, the linear compressor according to the present invention includes a case 2 (See FIG. 1) defining the outer appearance of the compressor, a body 140 located in the case 2 such that compressor's drive elements are assembled thereto, and an oil supply mechanism 150 provided in the case 2 to supply oil to a piston 16 (See FIG. 1) by use of power generated as the body 140 vibrates in a reciprocating movement direction of the piston 16. The linear compressor further includes an oil suction port 130 located in the case 2 (See FIG. 1) to suction the oil, the suction port 130 being formed in substantially the same direction as a vibrating direction of the body 140.

[41] The case 2 (See FIG. 1) defines the outer appearance of the linear compressor. As described above, the case 2 is provided, at one side thereof, with a refrigerant suction pipe 4 (See FIG. 1) to receive a refrigerant to be compressed, and a refrigerant discharge pipe 6 (See FIG. 1) to discharge the compressed refrigerant. [42] The body 140, to which the compressor's drive elements are assembled, is disposed in the case 2 (See FIG. 1) Specifically, the body 140 is supported in the case 2 by means of a damper 42 (See FIG. 1)

[43] Meanwhile, the linear compressor according to the present invention includes the oil supply mechanism 150, to supply the oil to the piston 16 (See FIG. 1) by use of power generated as the body 140 vibrates in a reciprocating movement direction of the piston 16 (See FIG. 1)

[44] As the piston 16 (See FIG. 1) is reciprocally moved by operation of a linear motor

20 (See FIG. 1) in order to compress the refrigerant, the body 140 performs a vibrating motion. In this case, it will be understood that the vibrating motion occurs in the reciprocating movement direction of the piston 16 (See FIG. 1)

[45] The oil supply mechanism 150 is configured to pump the oil by the vibrating motion of the body 140. More specifically, the oil supply mechanism 150 includes an oil piston 154 to be reciprocally moved in substantially the same direction as the vibrating direction of the body 140, and an oil cylinder 152 providing a space required for the reciprocating movement of the oil piston 154.

[46] As the body 140 vibrates, the oil piston 154 is moved upon receiving a force applied in the same direction as the vibrating direction of the body 140. The oil cylinder 152 serves to guide the movement of the oil piston 154.

[47] In this case, an elastic member 156 is provided to connect one end of the oil piston

154 with one end of the oil cylinder 152. Also, another elastic member 156 can be provided to connect the other end of the oil piston 154 with the other end of the oil cylinder 152.

[48] Wth the use of the elastic members 156, the oil piston 154 can be reciprocally moved within the oil cylinder 152 without colliding with both the ends of the oil cylinder 152. Also, if the oil piston 154 is moved in a direction of the oil cylinder 152, one of the elastic members 156 located at a leading end of the oil piston 154 is compressed, and the other elastic member 156 located at an opposite end of the oil piston 154 is extended. As a result, the elastic members 156 provide restoration forces for moving the oil piston 154 in an opposite direction.

[49] In brief, the oil piston 154 is reciprocally moved by the vibrating motion of the body 140 and the restoration forces provided by the elastic members 156.

[50] Meanwhile, the linear compressor according to the present invention further includes the oil suction port 130 formed in substantially the sanie direction as the vibrating direction of the body 140 and used to siction the oil. [51] The oil suction port 130 is immersed in the oil stored in the case 2 (See FIG. 1)

Preferably, the oil suction port 130 is formed at a distal end of a first oil pipe 132 extending in substantially the same direction as the vibrating direction.

[52] The present embodiment exemplifies the case in which the piston 16 (See FIG. 1) is reciprocally moved in a transversal direction, and consequently, the body 140 vibrates in a transversal direction. Accordingly, the oil suction port 130 has a transversal suction direction to correspond to the vibrating direction of the body 140. It will be appreciated that, when the body 140 vibrates in a longitudinal direction, the oil suction port 130 can be formed in a longitudinal direction to correspond to the vibrating direction of the body 140.

[53] In this case, the first oil pipe 132 extends in substantially the same direction as the suction direction of the oil suction port 130, and the oil suction port 130 is formed at the distal end of the first oil pipe 132.

[54] As described above, when the oil suction port 130, and a portion of the first oil pipe

132 near the oil suction port 130 are located in substantially the same direction as the vibrating direction of the body 140, it is possible to assure a sufficient supply amount of oil even if the linear compressor performs a refrigerant recovery operation.

[55] More specifically, the oil piston 154 is moved in the same direction as the vibrating direction of the body 140 under the influence of a momentum caused by the vibrating motion of the body 140. Also, the oil suction port 130 immersed in the oil vibrate in a direction corresponding to that of the momentum. With the vibrating motion of the oil suction port 130, the oil in the vicinity of the oil suction port 130 has a pressure difference due to an inertial force caused by the vibrating motion of the oil suction port 130. Such a pressure difference can assure efficient pumping of the oil. As a result, even if the interior pressure of the case 2 (See FIG. 1) is lowered, a uniform amount of oil can be pumped.

[56] In addition, to enhance the pressure difference of the oil by an inertial force, the first oil pipe 132 extends in substantially the same direction as the vibrating direction of the body 140.

[57] Meanwhile, the first oil pipe 132 is connected with one end of the oil cylinder 152.

In this case, there is further provided a second oil pipe 134 to guide the oil from one end of the oil cylinder 152 to the piston 16 (See FIG. 1)

[58] If the oil is introduced into the oil suction port 130 provided at the distal end of the first oil pipe 132 by a pumping operation of the oil piston 154, the oil is guided into the oil cylinder 152 through the first oil pipe 132, and then, guided to the piston 16 (See FIG. 1) through the second oil pipe 134.

[59] Here, junctions, where the first oil pipe 132 and the second oil pipe 134 are connected with the oil cylinder 152, are provided with a first opening/closing valve 158a and a second opening/closing valve 158b, respectively, to intercept the movement of the oil.

[60] The first opening/closing valve 158a, as shown in FIG. 4, can be installed such that it closes the first oil pipe 132 connected with the oil cylinder 152 when being moved to the left side of the drawing, and opens the first oil pipe 132 when being moved to the right side of the drawing.

[61] Also, the second opening/closing valve 158b can be installed such that it opens the second oil pipe 134 connected with the oil cylinder 152 when being moved to the left side of the drawing, and closes the second oil pipe 134 when being moved to the right side of the drawing.

[62] Hereinafter, the operation of the linear compressor according to the present invention, having the above described configuration, will be described.

[63] Upon operation of the linear compressor, the piston 16 (See FIG. 1) performs a reciprocating movement so as to compress the refrigerant. Wth the reciprocating movement of the piston 16 (See FIG. 1), the body 140 performs a vibrating motion. It will be appreciated that the body 140 vibrates in substantially the same direction as the movement direction of the piston 16 (See FIG. 1)

[64] Here, the oil piston 154 of the oil supply mechanism 150 is reciprocally moved in the same direction as the vibrating direction of the body 140 under the influence of the momentum caused by the vibrating motion of the body 140. As the oil piston 154 is moved, the interior pressure of the oil cylinder 152 is changed. Thereby, if the interior pressure of the oil cylinder 152 becomes smaller than the interior pressure of the case 2 (See FIG. 1), the oil begins to be pumped.

[65] More specifically, as shown in FIG. 4, if the oil piston 154 is moved to the right side of the drawing, a left space of the oil cylinder 152 on the basis of the oil piston 154 is lowered in pressure. Thereby, the first opening/closing valve 158a is opened, and the second opening/closing valve 158b is closed. In this case, the oil is introduced through the oil suction port 130, and is guided toward the piston 16 (See FIG. 1) through the first oil pipe 132.

[66] Also, if the oil piston 154 is moved to the left side of the drawing by the vibrating motion of the body 140 and the restoration forces of the elastic members 156, the left space of the oil cylinder 152 on the basis of the oil piston 154 is raised in pressure. Thereby, the first opening/closing valve 158a is closed, and the second opening/ closing valve 158b is opened. In this case, the oil within the oil cylinder 152 is introduced into the second oil pipe 134, and is supplied to the piston 16 (See FIG. 1) through the second oil pipe 134.

[67] Meanwhile, while the linear compressor performs a refrigerant recovery operation, the interior pressure of the case 2 (See FIG. 1) is lowered close to a vacuum pressure. This may make it impossible for the oil suction port 130 to suction the oil by a pumping operation of the oil piston 154.

[68] However, as described above, in the linear compressor according to the present invention, the oil suction port 130 immersed in the oil is formed in substantially the same suction direction as the vibrating direction of the body 140. As a result, the oil suction port 130 can be moved in the same direction as the vibrating direction by the vibrating motion of the body 140.

[69] In this case, the oil in the vicinity of the oil suction port 130 has a pressure difference due to an inertial force caused by the movement of the oil suction port 130. Such a pressure difference has the effect of assuring an efficient oil pumping operation. As a result, even if the interior pressure of the case 2 (See FIG. 1) is lowered, a uniform amount of oil can be supplied.

[70] In conclusion, even while the linear compressor performs a refrigerant recovery operation, a uniform amount of oil can be supplied to the piston 16 (See FIG. 1), thereby preventing the wear of constituent elements or the generation of particles, and achieving high system reliability.

[71] Meanwhile, the oil suction port 130 of the linear compressor according to the present invention can be configured to have any one of various shapes.

[72] For example, as shown in FIG. 6, to increase the suction amount of oil, a funnel- shaped oil suction port 130' may be used. The funnel-shaped oil suction port 130' can create a pressure difference in a further increased amount of oil upon a vibrating motion thereof. As a result, it is possible to maintain a sufficient supply amount of oil even during a refrigerant recovery operation as well as general operations of the linear compressor.

[73] It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents. Industrial Applicability

[74] As apparent from the above description, the present invention can be applied to the prediction of a linear compressor, which has the effects of assuring a sufficient supply amount of oil even if the interior pressure of a case is lowered close to a vacuum pressure while the linear compressor performs a refrigerant recovery operation, and maintaining a substantially uniform amount of oil to be supplied to a piston. Also, the present invention can be applied to the prediction of a refrigerator, air-conditioner, etc., using the linear compressor.

[75]

[76]

Claims

[1] A linear compressor comprising: a case defining the outer appearance of the compressor; a body located in the case and assembled with compressor's drive elements; an oil supply mechanism to supply oil to a piston by use of power generated as the body vibrates in a reciprocating movement direction of the piston; and an oil suction port formed in substantially the same direction as a vibrating direction of the body, to suction oil.

[2] The linear compressor according to claim 1, wherein the oil suction port is located in the oil stored in the case, and is formed at a distal end of a first oil pipe extending in substantially the same direction as the vibrating direction of the body.

[3] The linear compressor according to claim 2, wherein the oil supply mechanism comprises: an oil piston to be reciprocally moved in substantially the same direction as the vibrating direction of the body; and an oil cylinder providing a space required for the reciprocating movement of the oil piston.

[4] The linear compressor according to claim 3, wherein the oil supply mechanism further comprises elastic members provided, respectively, to connect one end of the oil piston with one end of the oil cylinder and to connect the other end of the oil piston with the other end of the oil cylinder.

[5] The linear compressor according to claim 4, wherein the first oil pipe is connected with one end of the oil cylinder.

[6] The linear compressor according to claim 5, further comprising: a second oil pipe to guide the oil from one end of the oil cylinder to the piston.

[7] The linear compressor according to claim 6, further comprising: a first opening/closing valve and a second opening/closing valve provided, respectively, at junctions where the first oil pipe and the second oil pipe are connected with the oil cylinder, to intercept the movement of the oil.

[8] A linear compressor comprising: a piston to be reciprocally moved within a predetermined range; an oil pipe having an oil suction port formed in substantially the same direction as a reciprocating movement direction of the piston, the oil pipe creating a pressure difference in oil in the vicinity of the oil suction port under the influence of vibrations caused by the reciprocating movement of the piston; and an oil supply mechanism connected with the oil pipe and used to suction the oil from the oil suction port so as to supply the oil to the piston.

[9] The linear compressor according to claim 8, wherein the oil supply mechanism uses power generated by the vibrations.

[10] The linear compressor according to claim 8 or 9, wherein the oil supply mechanism comprises: an oil piston to be reciprocally moved in substantially the same direction as a vibrating direction; and an oil cylinder providing a space required for the reciprocating movement of the oil piston.

[11] The linear compressor according to claim 10, wherein the oil supply mechanism further comprises elastic members, respectively, to connect one end of the oil piston with one end of the oil cylinder and to connect the other end of the oil piston with the other end of the oil cylinder.

[12] The linear compressor according to claim 8 or 9, wherein the oil suction port has a funnel shape.

[13] A linear compressor comprising: a case defining the outer appearance of the compressor; a piston to be reciprocally moved in the case within a predetermined range; an oil supply mechanism to supply oil to the piston by use of power generated by vibrations in a reciprocating movement direction of the piston; and an oil suction port formed in substantially the same direction as the reciprocating movement direction of the piston, to allow the oil supply mechanism to supply a substantially uniform amount of oil to the piston even when the case has a low interior pressure.

[14] The linear compressor according to claim 13, further comprising: an oil pipe to connect the oil supply mechanism and the oil suction port with each other.