US20070148018A1

US20070148018A1 - Reciprocating compressor

Info

Publication number: US20070148018A1
Application number: US11/642,837
Authority: US
Inventors: Jong-Tae Her
Original assignee: LG Electronics Inc
Current assignee: LG Electronics Inc
Priority date: 2005-12-23
Filing date: 2006-12-21
Publication date: 2007-06-28
Also published as: DE102006059762A1

Abstract

A reciprocating compressor is provided. The compressor includes a casing, a frame fixed to an inner circumferential surface of the casing, an oil storage portion formed in the frame, and an oil pocket formed at an outer circumferential surface of a piston and in communication with the oil storage portion. The piston reciprocates within a cylinder and pumps oil based on a change in volume of the oil in the oil pocket. Since an additional space to contain oil in the casing and an additional oil pumping device are not required, size of the compressor is reduced and structure is simplified. Furthermore, since oil is automatically pumped when the piston reciprocates, reliability of the compressor is enhanced.

Description

This application claims priority to Korean Application No. 10-2005-0129085, filed in Korea on Dec. 23, 2005, the entirety of which is incorporated herein by reference .

BACKGROUND OF THE INVENTION

1. Field
The field relates to a compressor, and more particularly, to a reciprocating compressor.
2. Background
In general, a compressor converts mechanical energy into compressive energy. Compressors may typically be categorized into a reciprocating type, a scroll type, a centrifugal type and a vane type. Reciprocating compressors may be further categorized into a horizontal type compressor, and a vertical type reciprocating compressor.
Due to the need to provide for lubrication of various components, combined with the placement and orientation of the various components of the horizontal and vertical type reciprocating compressors, additional space is required in the casing to accommodate the oil. Further, in a horizontal type reciprocating compressor, assembly is complicated due to the large number of components of the oil pump, and oil is not smoothly and continuously provided when oil viscosity is high. Likewise, the vertical orientation of the components of a vertical type reciprocating compressor makes it difficult to pump oil to the various components, thus decreasing reliability of the compressor.
Descriptions of reciprocating compressors and operation thereof can be found in, for example, U.S. Pat. Nos. 6,875,000, 6,875,001, and 6,863,506, which are subject to an obligation of assignment to the same entity, and the entirety of which is incorporated herein by reference.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments will be described in detail with reference to the following drawings in which like reference numerals refer to like elements wherein:
FIG. 1 is a cross-sectional view of an exemplary vertical type reciprocating compressor having an oil pumping system as embodied and broadly described herein;
FIG. 2 is a cross-sectional view of the exemplary compressor shown in FIG. 1 which illustrates an oil suction process as embodied and broadly described herein;
FIG. 3 is a cross-sectional view of the exemplary compressor shown in FIG. 1 which illustrates an oil supply process as embodied and broadly described herein;
FIG. 4 is a cross-sectional view of another exemplary vertical type reciprocating compressor having an oil pumping system as embodied and broadly described herein;
FIG. 5 is a cross-sectional view of another exemplary vertical type reciprocating compressor having an oil pumping system as embodied and broadly described herein; and
FIGS. 6-8 are exemplary installations of the exemplary compressors shown in FIGS. 1, 4 and 5.

DETAILED DESCRIPTION

A reciprocating compressor having an oil pumping system in accordance with embodiments as broadly described herein is shown in FIG. 1. Although a reciprocating compressor, and particularly a horizontal type reciprocating compressor, is presented for ease of discussion, it is well understood that an oil pumping assembly as embodied and broadly described herein may be applied to other types of compressors and/or other applications which require fluid pumping as described herein. The exemplary reciprocating compressor includes a casing 100, a suction pipe SP and a discharge pipe DP extending through the casing 100, a reciprocating motor 200 installed in the casing 100 and having a linearly-reciprocating mover 230, and a compression unit 300 which compresses fluid as a piston 320 coupled to the mover 230 of the reciprocating motor 200 reciprocates with the mover 230.
The reciprocating motor 200 may include an outer stator 210 having a winding coil 211 thereon, an inner stator 220 installed in the outer stator 210 with a certain gap therebetween, and a mover 230 having a magnet 231 positioned in an air gap between the outer stator 210 and the inner stator 220.
The outer stator 210 is supported by first and second fixed frames 240 and 250 coupled to opposite ends of the mover 230 by, for example, a bolt or other suitable fastener, and is fixedly coupled to the casing 100. The inner stator 220 may be pressed-fit to an outer circumferential surface of the first fixed frame 240.
In certain embodiments, the first fixed frame 240 has a disc shape with an outer diameter similar to that of the outer stator 220, with a cylindrical fixing protrusion 241 which extends in a backward direction. The inner stator 220 is installed onto an outer circumferential surface of the first fixed frame 240, and a cylinder 310 is inserted into an inner circumferential surface of the first fixed frame 240.
An oil storage portion 242 for receiving oil at the time of assembling the compressor may be formed in the compressor. In the exemplary compressor shown in FIG. 1, the oil storage portion 242 is formed in a ring shape at an inner side surface of the first fixed frame 240. Other locations and shapes may also be appropriate. An oil passing hole 243 may be formed, for example, at the fixing protrusion 241 of the first fixed frame 240 so as to be connected to an oil pocket 323 formed between the cylinder 310 and the piston 320.
The mover 230 may be coupled to an outer circumferential surface of a movable frame 232 on which a plurality of magnets 231 is arranged between the outer stator 210 and the inner stator 220. The movable frame 232 may be formed in, for example, a cylindrical shape having two opened sides. A rear side of the two opened sides has portions which extend inward towards the center so as to be coupled to the piston 320 of the compression unit 300 by, for example, a bolt or other suitable fastener.
The compression unit 300 may include a cylinder 310 inserted into and fixed to the fixing protrusion 241, a piston 320 coupled to the mover so as to reciprocate in a compression space 311 of the cylinder 310, a plurality of resonance springs 330 and 340 which elastically support forward and rear sides of the piston 320, a suction valve 350 provided at an end surface of the piston 320 so as to open and close a suction channel 321 a of the piston 320, thereby regulating suction of fluid as necessary, a discharge valve 360 mounted at a discharge side of the cylinder 310 which opens and closes the compression space 311, thereby regulating discharge of fluid, a valve spring 370 which elastically supports the discharge valve 360, and a discharge cover 380 which covers a discharge side of the cylinder 310, and in which the discharge valve 360 and the valve spring 370 are received. The discharge cover 380 is inserted into a cover insertion hole 110 provided at an appropriate side of the casing 100.
The cylinder 310 may have a cylindrical shape with smooth outer and inner circumferential surfaces. An oil passing hole 312 is formed in the cylinder 310 at a portion corresponding to the oil passing hole 243 formed in the first fixed frame 240. The oil passing hole 312 receives oil from the oil passing hole 243 and guides the oil towards an oil pocket 323 formed between the cylinder 310 and the piston 320. Thus, the oil passing hole 312 is positioned with a reciprocation range of a portion of the pistion 320 which includes the oil pocket 323.
A plurality of bearings 321 and 322 are provided at an outer circumferential surface of the piston 320, in sliding contact with an inner circumferential surface of the cylinder 310. The oil pocket 323 has a predetermined volume so that a pressure difference can be generated when the piston 310 is reciprocated due to its concave shape between the bearings 321 and 322.
In certain embodiments, the bearings 321 and 322 of the piston 320 have the same outer diameter, as shown, for example, in FIGS. 2 and 3. In certain embodiments, the oil pocket 323 is formed at a position higher than the oil passing hole 243 so that a pressure difference can be generated when oil is contained in the oil passing hole 243 of the cylinder 310. In certain embodiments, resonance springs 330 and 340 are compression coil springs. One end of the front, or first resonance spring 330 may be fixed to a front side of a connection portion 332 of the piston 320, and another end of the first resonance spring 330 may be fixed to the second fixed frame 250. One end of the rear, or second resonance spring 340 may be fixed to a rear side of the connection portion 332 of the piston 320, and another end of the second resonance spring 340 may be fixed to an inner circumferential surface of the casing 100.
In certain embodiments, the suction valve 350 may include a fixed portion 351 which remains fixed to an end surface of the piston 320, and an opening/closing portion 352 which opens and closes the suction channel 321 a of the piston 320. In certain embodiments, the discharge valve 360 may be formed of, for example, an engineered plastic material. Other materials may also be appropriate. A compression surface of the discharge valve 360 may be detachably coupled to an end surface of the cylinder 310 so as to be opened and closed. A rear surface of the compression surface may have a semi-spherical shape, as shown, for example, in FIG. 1, or other shape as appropriate.
In certain embodiments, valve spring 370 may be, for example, a cylindrical or a conical compression coil spring. One end of the valve spring 370 may be fixed to the rear surface of the compression surface of the discharge valve 360, and another end thereof may be fixed to an inner surface of the discharge cover 380, as shown, for example, in FIG. 1. When the valve spring 370 has a conical shape, a relatively wide side of the valve spring 370 may be fixed to the discharge cover 380 to provide stability.
In certain embodiments, discharge cover 380 may form a single discharge space 381, as shown, for example, in FIG. 1. In alternative embodiments, the discharge cover 380 may form a plurality of discharge spaces (not shown). The discharge cover 380 is installed so that a portion of the discharge cover which defines the discharge space 381 is exposed through the cover insertion hole 110 of the casing 100. A coupling flange portion 382 formed at an outer circumferential surface of an opened side of the discharge cover 380 may be hermetically coupled to an outer surface of the first fixed frame 240.
When power is supplied to the winding coil 211 fixed to the outer stator 210, a flux is generated between the outer stator 210 and the inner stator 220. This flux causes the mover 230, which is positioned between the outer stator 210 and the inner stator 220, to be continuously reciprocated along a direction of the flux. Reciprocation of the mover 230 causes the piston 320 coupled to the mover 230 to be accordingly reciprocated in the cylinder 310, and a volume of the compression space 311 formed between the cylinder 310 and the piston 320 is changed. As a result, fluid is sucked into the compression space 311, compressed, and then discharged.
As shown in FIG. 2, when the piston 320 performs a forward motion (compression stroke), a volume (A) of the oil pocket 323 is decreased, thus increasing pressure in the oil pocket 323. Then, as shown in FIG. 3, when the piston 320 performs a backward motion (suction stroke), a volume (B) of the oil pocket 323 is decreased, thus lowering pressure in the pocket 323 and thereby generating a pressure difference. A suction force is generated at the oil pocket 323 due to the pressure difference. The oil contained in the oil storage portion 242 of the first fixed frame 240 is sucked into the oil pocket 323 via the oil passing hole 243 formed in the first fixed frame 240 and the oil passing hole 312 formed in the cylinder 310. Then, the oil provides for lubrication between the cylinder 310 and the piston 320 by contacting an outer circumferential surface of the bearings 321 and 322 of the piston 320 and/or an inner circumferential surface of the cylinder 310 when the piston 320 is reciprocated.
In this first embodiment, the oil pocket 323 is formed only on an outer circumferential surface of the piston 320. However, in accordance with the second and third embodiments shown in FIGS. 4 and 5, respectively, a movable oil pocket 324 may be formed on the outer circumferential surface of the piston 320, and a fixed oil pocket 313 may be formed on the inner circumferential surface of the cylinder 310. The fixed oil pocket 313 and the movable oil pocket 324 may be formed so as to extend higher than the oil passing holes 243 and 312.
In certain embodiments, outer diameters D1 and D2 of the bearings 321 and 322 positioned on opposite sides of the pocket may be equal, as shown, for example, in FIG. 5. In alternative embodiments, outer diameters D1 and D2 may be different, as shown, for example, in FIG. 5.
When the fixed oil pocket 313 is formed at the cylinder 310 and the movable oil pocket 324 is formed at the piston 320, an oil pumping process is similar to the aforementioned process, and thus a detailed explanation is omitted.
In a compressor as embodied and broadly described herein, the oil storage portion 242 is formed between the frame 240 and the cylinder 310, and the oil pocket 323 or pockets 313, 323 which generates a pressure difference is formed between the cylinder 310 and the piston 320. The oil inside the oil storage portion 242 is pumped between the cylinder 310 and the piston 320 by the pressure difference generated in the oil pocket 323 or pockets 313, 324. Thus, a compressor as embodied and broadly described herein does not require additional space to contain oil therein, nor an additional oil pumping device. Accordingly, a size of the compressor can be minimized, and a structure thereof can be simplified, thereby improving an assembly process.
When the piston is reciprocated, oil is pumped thus generating an increased pumping force. Furthermore, since oil can be pumped only if the piston is reciprocated, a reliability for the oil pumping operation is enhanced.
A compressor having an oil pumping system as embodied and broadly described herein has numerous applications in which compression of fluids is required, and in different types of compressors. Such applications may include, for example, air conditioning and refrigeration applications. One such exemplary application is shown in FIG. 6, in which a compressor 610 having an oil pumping assembly as embodied and broadly described herein is installed in a refrigerator/freezer 600. Installation and functionality of a compressor in a refrigerator is discussed in detail in U.S. Pat. Nos. 7,082,776, 6,955,064, 7,114,345, 7,055,338 and 6,772,601, the entirety of which are incorporated herein by reference.
Another such exemplary application is shown in FIG. 7, in which a compressor 710 having an oil pumping assembly as embodied and broadly described herein is installed in an outdoor unit of an air conditioner 700. Installation and functionality of a compressor in a refrigerator is discussed in detail in U.S. Pat. Nos. 7,121,106, 6,868,681, 5,775,120, 6,374,492, 6,962,058, 6,951,628 and 5,947,373, the entirety of which are incorporated herein by reference.
Another such exemplary application is shown in FIG. 8, in which a compressor 810 having an oil pumping assembly as embodied and broadly described herein is installed in a single, integrated air conditioning unit 800. Installation and functionality of a compressor in a refrigerator is discussed in detail in U.S. Pat. Nos. 7,032,404, 6,412,298, 7,036,331, 6,588,228, 6,182,460 and 5,775,123, the entirety of which are incorporated herein by reference.
An object is to provide a reciprocating compressor with an oil supplying device having a high reliability, the compressor being capable of reducing production cost with a small size and a small number of components.
To achieve these and other advantages, and in accordance embodiments as broadly described herein, there is provided a reciprocating compressor, including a frame for supporting a stator of a reciprocating motor having a reciprocated mover, a cylinder insertion-fixed to the frame and having one or more oil passing holes for passing oil in a radial direction thereof, and a piston slidably inserted into the cylinder thus to be coupled to the mover, and having an oil pocket on an outer circumferential surface thereof, the oil pocket connected to the oil passing hole of the cylinder thus to generate a pressure difference due to a volume change.
In accordance with another embodiment as broadly described herein, there is provided a reciprocating compressor, including a frame for supporting a stator of a reciprocating motor having a reciprocated mover, a cylinder insertion-fixed to the frame, having one or more oil passing holes for passing oil in a radial direction thereof, and having a fixed oil pocket concaved at an inner circumferential surface thereof connected to the oil passing hole, and a piston sidably inserted into the cylinder thus to be coupled to the mover, and having a movable oil pocket concaved at an outer circumferential surface thereof so as to generate a pressure difference due to a volume change together with the fixed oil pocket of the cylinder.
In accordance with another embodiment as broadly described herein, there is provided a reciprocating compressor, including a casing, a frame fixedly coupled to an inner circumferential surface of the casing, and having an oil storage portion concaved at an outer circumferential surface thereof, a reciprocating motor having a stator fixedly coupled to the frame, and a mover reciprocated in a vertical direction, a cylinder insertion-fixed to the frame and having one or more oil passing holes connected to the oil storage portion of the frame for passing oil, and a piston slidably inserted into the cylinder thus to be coupled to the mover, and having an oil pocket at a contact surface with the cylinder, the oil pocket connected to the oil passing hole of the cylinder for pumping oil of the oil storage portion with generating a pressure difference due to a volume change.
Any reference in this specification to “one embodiment,” “an exemplary,” “example embodiment,” “certain embodiment,” “alternative embodiment,” and the like means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment as broadly described herein. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with any embodiment, it is submitted that it is within the purview of one skilled in the art to affect such feature, structure, or characteristic in connection with other ones of the embodiments.
Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, numerous variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.

Claims

1. A compressor, comprising:

a frame configured to support a reciprocating motor having a stator and a mover;

a cylinder inserted into and coupled to the frame, wherein the cylinder and the frame each have at least one passage formed in a respective radial direction thereof which are configured to allow fluid to flow therethrough; and

a piston configured to be slidably inserted into the cylinder and to be coupled to the mover, wherein the piston comprises a pocket formed on an outer circumferential surface thereof, wherein the pocket is connected to the at least one passage formed in the cylinder so as to generate a pressure difference therebetween based on a volume of fluid in the pocket.

2. The reciprocating compressor of claim 1, wherein the compressor comprises a horizontal or a vertical reciprocating compressor.

3. The reciprocating compressor of claim 1, wherein a storage portion configured to receive a predetermined amount of fluid therein as formed as a recess in the frame, and wherein the at least one passage formed in of the cylinder is in communication with storage portion.

4. The reciprocating compressor of claim 3, wherein the at least one passage formed in the frame provides for fluid communication between the storage portion and the at least one passage formed in the cylinder.

5. The reciprocating compressor of claim 1, wherein an inner circumferential surface of the cylinder is in sliding-contact an outer circumferential surface of the piston which excludes the pocket.

6. The reciprocating compressor of claim 1, wherein a vertical length of the pocket is greater than a diameter of the at least one passage formed in the cylinder, and wherein an upper end of the pocket is positioned higher than the at least one passage formed in the cylinder.

7. The reciprocating compressor of claim 1, wherein the at least one passage formed in the cylinder is positioned within a reciprocation range of the pocket.

8. A reciprocating compressor, comprising:

a frame configured to support a reciprocating motor having a mover and a stator;

a cylinder inserted into and coupled to the frame, wherein the cylinder has at least one passage formed in a radial direction thereof, and a fixed pocket formed as a recess in an inner circumferential surface thereof which is in communication with the at least one passage formed in the cylinder; and

a piston coupled to the mover and configured to be slidably inserted into the cylinder, wherein the piston comprises a movable pocket formed as a recess in an outer circumferential surface thereof, wherein the moveable pocket and the fixed pocket are configured to generate a pressure difference due to a corresponding change volume.

9. The reciprocating compressor of claim 8, further comprising a fluid storage portion formed as a recess in the frame, wherein the at least one passage formed in the cylinder is positioned proximate the storage portion.

10. The reciprocating compressor of claim 9, further comprising a passage formed in the frame which extends between the storage portion and the at least one passage formed in the cylinder so as to provide for fluid communication therebetween.

11. The reciprocating compressor of claim 8, wherein an inner circumferential surface of the cylinder which excludes the fixed pocket is in sliding contact with an outer circumferential surface of the piston which excludes the moveable pocket.

12. The reciprocating compressor of claim 8, wherein an outer diameter of the piston is substantially uniform except for a portion thereof which forms the moveable pocket, and wherein an inner diameter the cylinder varies such that an inner circumferential surface of the cylinder which excludes the fixed pocket maintains sliding-contact with an outer circumferential surface of the piston which excludes the moveable pocket.

13. The reciprocating compressor of claim 8, wherein a length of the fixed pocket and a length of the moveable pocket in a vertical direction are each greater than a diameter of the at least one passage formed in the cylinder, and wherein upper ends of the fixed and moveable pockets are positioned higher than the at least one passage formed in the cylinder.

14. The reciprocating compressor of claim 8, wherein the at least one passage formed in the cylinder is positioned within a reciprocation range of the fixed and moveable pockets.

15. A reciprocating compressor, comprising:

a casing:

a frame coupled to an inner circumferential surface of the casing, comprising a fluid storage portion formed as a recess along an outer circumferential surface thereof;

a reciprocating motor having a stator coupled to the frame and a mover configured to reciprocate in a vertical direction;

a cylinder fixed to the frame and having at least one passage in communication with the storage portion of the frame;

a piston coupled to the mover and configured to be slidably inserted into the cylinder; and

a pocket formed at either the cylinder or the piston so as to be in communication with the at least one passage formed in the cylinder, wherein the pocket is configured to generate a pressure difference due to a change in volume of a fluid in the pocket when the piston is reciprocated.

16. The reciprocating compressor of claim 15, wherein the storage portion has a ring shape.

17. The reciprocating compressor of claim 15, wherein the at least one passage formed in the cylinder is positioned within a reciprocation range of the pocket.

18. The reciprocating compressor of claim 15, wherein the pocket is formed in the piston, and wherein an outer diameter of the piston is substantially uniform except for a portion thereof which forms the pocket, and wherein an inner diameter or the cylinder is substantially uniform such that an inner circumferential surface thereof maintains sliding-contact with an outer circumferential surface of the piston which excludes the pocket.

19. The reciprocating compressor of claim 15, wherein the pocket is formed in the piston, and wherein an outer diameter of the piston varies, and wherein an inner diameter of the cylinder varies corresponding to the outer diameter of the piston such that an inner circumferential surface of the cylinder maintains sliding-contact with an outer circumferential surface of the piston which excludes the pocket.

20. The reciprocating compressor of claim 15, wherein a vertical length of the pocket is greater than a diameter of the at least one passage formed in the cylinder, and wherein an upper end of the pocket is positioned higher than an upper end of the at least one passage.