WO2004094830A1

WO2004094830A1 - Rotary type compressor

Info

Publication number: WO2004094830A1
Application number: PCT/KR2003/000804
Authority: WO
Inventors: Hyun Kim; Chul-Gi Roh
Original assignee: Lg Electronics Inc.
Priority date: 2003-04-19
Filing date: 2003-04-19
Publication date: 2004-11-04
Also published as: AU2003222483A1

Abstract

Rotary compressor including a compression chamber (200) having one suction port (51) and two discharge ports (61,63), a rolling member eccentric (80) from a center of the compression chamber (200), mounted to roll on, and revolve along a wall surface (50) of the compression chamber (200) in either direction, for compressing a portion of a space of the compression chamber, and a dividing member (90) disposed between the discharge ports (61,63), and fitted to maintain contact with the rolling member (80) always, for dividing the suction part and the discharge part (210,220), thereby permitting to vary a compression volume as the rotary compressor varies a rotation direction.

Description

ROTARY TYPE COMPRESSOR

Technical Field

The present invention relates to compressors, and more particularly, to a reversible rotary compressor. Background Art

In general, the compressor is a machine for boosting a pressure of a working fluid by receiving a power from a power generating apparatus, such as an electric motor or a turbine, and applying a compression work to air, refrigerant or other gases. The compressors are used starting from general home appliances, such as the field of air conditioners, or the field of refrigerators, to plant industry.

There are positive displacement type compressors and dynamic compressors or turbo compressors in the compressors depending on compression types.

Of the compressors, those used in industrial sites are the positive displacement type compressors, in which a volume is reduced to boost a pressure. In the positive displacement type compressors, there are reciprocating type compressors and rotary type compressors.

The reciprocating type compressor, compressing the working fluid by means of a piston which makes linear reciprocating movement within a cylinder, has comparably simple mechanical components and a high compression efficiency.

Contrary to this, the reciprocating type compressors has a limitation in a rotation speed due to an inertia of the piston, and substantial vibration caused by the inertia.

The rotary compressor, compressing the working fluid by means of a roller revolving an inside of a cylinder with an eccentricity, can produce a high compression efficiency at a speed lower than the reciprocating type compressor. The rotary compressor has a low vibration and noise. However, despite of above various advantages, bi-directional revolution of the roller has been impossible due to a structural limit. That is, the related art rotary compressor has a suction port and a discharge port in communication with the cylinder, and the roller rolls along the inside circumferential surface of the cylinder from the suction port side to the discharge port side for compressing the working fluid. Consequently, when the roller rolls in an opposite direction (from the discharge port to the suction port), the compression of the working fluid can not, but be impossible.

Moreover, variation of a compression volume has been impossible due to the foregoing structure of the related art rotary compressor. Recently, compressors with variable compression capacities appear for coping with various operation conditions of air conditioners and the like. However, since the related art rotary compressor can not, but has only one compression volume, application range of the rotary compressor can not, but be small. Disclosure of Invention An object of the present invention is to provide a reversible rotary compressor.

Another object of the present invention is to provide a rotary compressor with a variable compression volume.

The object of the present invention can be achieved by providing a rotary compressor including a compression chamber having one suction port and two discharge ports, a rolling member eccentric from a center of the compression chamber, mounted to roll on, and revolve along a wall surface of the compression chamber in either direction, for compressing a portion of a space of the compression chamber, and a dividing member disposed between the discharge ports, and fitted to maintain contact with the rolling member always, for dividing the suction part and the discharge part. Any one of the discharge ports is a gas discharge passage when the rolling member revolves in a clockwise direction, and the other one is a gas discharge passage when the rolling member revolves in a counter clockwise direction. In this instance, the gas inside of the compression chamber can be compressed to a predetermined compression ratio regardless of the revolving direction of the rolling member.

The compression ratio is dependent on a position of the suction port as well as the revolving direction of the rolling member. Because the compression ratio is dependent on a volume of the discharge part, and the volume of the discharge part is dependent on a position of the suction port. Therefore, it can be known that keeping the compression ratio constant or varying the compression ratio is possible by adjusting the position of the suction port.

Based on this principle, primarily, the present invention provides a reversible rotary compressor, and moreover, a rotary compressor of which compression volume is variable. At first, for obtaining a fixed compression ratio regardless of the revolving direction of the rolling member, the suction port is formed on an extension line from the dividing member. In this instance, the compression chamber is divided into two parts having equal volumes. Accordingly, a fixed compression ratio is always obtainable regardless of the revolving direction of the rolling member. Next, for obtaining compression ratios different from each other depending on the revolving direction of the rolling member, the suction port is formed on either side of the extension line from the dividing member. In this instance, the compression chamber is divided into two parts having different volumes. According to this, compression ratios different from each other depending on the revolving direction of the rolling member can be obtained. In this instance, it is preferable that the suction port is positioned within a range of 180° ~ 300° from the dividing member in either direction.

In the meantime, the present invention further includes opening/closing members for opening the discharge ports when a pressure inside of the discharge part is higher than a preset pressure.

The present invention further includes a rotating member for selectively revolving the rolling member in a clockwise or counter clockwise direction.

The present invention further includes bearing members for supporting the rotating member and forming the compression chamber. The present invention further includes a supporting member for elastic supporting of the dividing member so as to make the dividing member to be in contact with the rolling member always. Brief Description of Drawings

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 principles of the invention: In the drawings:

FIG. 1 illustrates a longitudinal section of a rotary compressor in accordance with a preferred embodiment of the present invention; FIG. 2 illustrates a disassembled perspective view of a compression part of a rotary compressor in accordance with a preferred embodiment of the present invention;

FIG. 3 illustrates a cross section showing an inside of a cylinder of a rotary compressor in accordance with a preferred embodiment of the present invention;

FIGS. 4A ~ 4C illustrate cross sections showing actions when a roller revolves in a counter clockwise direction in succession in a rotary compressor in accordance with a preferred embodiment of the present invention; and

FIGS. 5 A ~ 5C illustrate cross sections showing actions when a roller revolves in a clockwise direction in succession in a rotary compressor in accordance with a preferred embodiment of the present invention. Best Mode for Carrying Out the Invention

Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. FIG. 1 illustrates a longitudinal section of a rotary compressor in accordance with a preferred embodiment of the present invention, and FIG. 2 illustrates a disassembled perspective view of a compression part of a rotary compressor in accordance with a preferred embodiment of the present invention.

Referring to FIG. 1 , the rotary compressor includes a case 1 , an electric motor part in an upper part of the case 1, and a compression part under the electric motor part.

The case 1 having an upper cap 3 and a lower cap 5 forms an enclosed space. The case 1 has a suction pipe 7 at one side for drawing gas, and a discharge pipe 9 at a center of the upper cap 3 for discharge the gas. The suction pipe 7 is connected to an accumulator 10.

The motor part includes a stator 20 fixed to the case 1 , a rotor rotatably held inside of the stator 20, and a crankshaft 40 press fit to the rotor 30. The rotor 30 is rotated by electro-magnetic force, and the crankshaft 40 transmits a rotation force of the rotor 30 to the compression part. For providing an external power to the stator 20, there is a hermetic terminal 4 provided to the upper cap 3.

The compression part includes a cylinder 50 fixed to the case 1, a roller 80 for rolling along an inside circumferential surface of the cylinder 50 to compress a gas, and an upper bearing 60 and a lower bearing 70 for rotatably supporting the crankshaft 40. The upper bearing 60 and the lower bearing 70 form a compression chamber 200 in association with the cylinder 200.

The compression part will be described in more detail. Referring to FIG. 2, the crankshaft 40 has an eccentric part 41 in a lower part. The eccentric part 41 has a center at a position a distance away from a rotation center of the crankshaft 40. The eccentric part 41 may be formed as one unit with the crankshaft 40, or as an eccentric piece inserted in the crankshaft 40.

The cylinder 50 having opened top and bottom holds the eccentric part 41 therein. The cylinder 50 has a suction port 51 in a sidewall for communication with an exterior. The suction port 51 is a flow passage for guiding the gas into the compression chamber. The suction port 51 is formed in a direction perpendicular to the crankshaft 40, and connected to the suction pipe 7 (see FIG. 1). The cylinder 50 has a slot 53 in the sidewall of the cylinder 50 with a depth from an inside surface thereof. The slot 53 is a space for fitting a vane 90 which will be described later. The depth of the slot 53 is adequate for receiving the vane 90, fully.

The roller 80, a ring having an outside diameter smaller than an inside diameter of the cylinder 50, is combined with the eccentric part 41. The roller 80 is to roll along the inside circumferential surface of the cylinder 50. To do this, the roller 80 is provided so as to be rotatable with respect to the eccentric part 41. Or, the roller 80 may be fixed to the eccentric part 41 , if the eccentric part 41 is provided to be rotatable with respect to the crankshaft 40.

The vane 90 is fitted in the slot 53 of the cylinder 50. The vane 90 is a member which divides the compression chamber 200 (see FIG. 1) into a suction part for drawing the gas, and a discharge part for discharging a compressed gas. To do this, it is required that the vane 90 is always in contact with an outside circumferential surface of the roller 80. However, when the crankshaft 40 is rotated, the roller 80 revolves around a center of the compression chamber 200. Therefore, for keeping a close contact between the vane 90 and the roller 80, it is necessary to provide the vane 90 elastically. For this, a spring 95 is provided in the slot 53 of the cylinder 50. That is, one end of the spring 95 is fixed to the cylinder 50, and the other end is joined with the vane 90 for pushing the vane 90 toward the roller 80.

The upper bearing 60 and the lower bearing 70 pass through the crankshaft 40 and engage with a top surface and a bottom surface of the cylinder 50 respectively. The upper bearing 60, the lower bearing 70 and the cylinder 50 have a plurality of fastening holes 65, 75, and 55 at matched positions. Accordingly, the cylinder 50 and the bearings 60 and 70 are joined with separate fastening screws, together. In this instance, the cylinder 50 and bearings 60 and 70 are joined tightly for prevention of gas leakage.

The upper bearing 60 has two discharge ports 61 and 63 (see FIG. 1). The discharge ports 61 and 63, in communication with the compression chamber 200, provide discharge passage of the compressed gas. Two discharge valves 110 and 120 are provided to the upper bearing 60. The discharge valves 110 and 120 open the discharge ports 61 and 63 only when a pressure of the compression chamber 200 is higher than a preset pressure. To do this, it is preferable that the discharge valves 110 and 120 are plate springs each of which has one end held in the vicinity of the outlet port 61 or 63, and the other end left free.

In the meantime, referring to FIG. 1, there is a retainer 130 over each of the discharge valves 110 and 120. The retainers 130, for assuring a stable operation of the discharge valves 110 and 120, are provided so as to come into contact with the discharge valves 110 and 120 for limiting an extent of opening of the discharge valves 110 and 120. If there are not retainers provided thereto, it is liable that the discharge valves 110 and 120 are bent due to an excessive pressure. In this case, an operation reliability of the discharge valves 110 and 120 will become poor.

There is a muffler 140 in an upper part of the upper bearing 60. The muffler 140 attenuates noise produced when the compressed gas is discharged. To do this, the muffler 140 encloses an upper space of the discharge ports 61 and 63, and has a separate discharge opening 141 at one side.

An amount of lubricating oil 'O' is filled in a bottom of the case 1 for lubrication and cooling. An end of the crankshaft 40 is submerged in the lubricating oil 'O'. A revolution direction of the roller 80 and a position of the suction port 51 are very important factors for achieving the objects of the present invention, correlation of which will be described in detail.

FIG. 3 illustrates a cross section showing an inside of a cylinder of a rotary compressor in accordance with a preferred embodiment of the present invention. Referring to FIG. 3, the compression chamber 200 is divided into two parts 210 and 220 by the vane 90 and the roller 80, with the discharge ports 61 and 63 disposed oppositely with reference to the vane 90. This is for compressing the gas always, regardless of the revolving direction of the roller 80. That is, regardless of the revolving direction of the roller 80, either one of the discharge ports 61 or 63 presents between the suction port 51 and the vane 90. In this instance, it is preferable that distances between the vane 90 and the discharge ports 61 or 63 are equal.

The compression chamber 200 is divided into the suction part for drawing gas through the suction port 51, and the discharge part for discharging compressed gas through either discharge port 61 or 63. The suction part and the discharge part are fixed depending on the revolving direction of the roller 80. That is, if the roller 80 revolves in a counter clockwise direction, a right side space 210 of the roller 80 is the discharge part, and if the roller 80 revolves in a clockwise direction, a left side space 210 of the roller 80 is the discharge part.

In the meantime, a compression volume is fixed according to a volume of the discharge part 210 or 220. The volume of the discharge part 210 or 220 is a volume enclosed by the cylinder 50 and the roller 80 starting from the suction port 51 to the vane 90. Therefore, the compression volume is dependent on the position of the suction port 51.

For an example, when the suction port 51 is positioned on an imaginary line that passes through the vane 90, i.e., at 180° from the vane 90, the compression chamber 200 is divided into two parts of equal volumes. Therefore, regardless of the revolving direction of the roller 80, the compression volumes are equal.

However, if the suction port is positioned on either side of the imaginary line which passes through the vane 90, the compression chamber 200 is divided into two parts of different volumes. That is, referring to FIG. 3, the compression chamber 200 is divided into a left side space 220 having a shorter distance from the vane 90 to the suction port 51 , and a right side space having a farther distance from the vane 90 to the suction port 51. In this instance, either space 210 or 220 becomes the discharge part depending on the revolving direction of the roller 80, to divide the compression part into a high pressure discharge part 210 with a greater volume, and a low pressure discharge part 220 with a smaller volume. This implies that the rotary compressor of the present invention has dual capacities depending on the revolving direction of the roller 80.

The position of the suction port 51 is fixed according to a compression ratio of the high pressure compression part 210 and the low pressure compression part 220. For an example, the present invention suggests the suction port 51 to be positioned in a range of 180° ~ 300° from the imaginary line which passes through the vane 90 in the clockwise direction. If the compression ratio is 50:50, as described before, the suction port 51 is positioned at 180°. If the compression ratio is 75:25, the suction port 51 is positioned at 270°.

The operation of the rotary compressor of the present invention will be described in more detail. FIGS. 4A ~ 4C illustrate cross sections showing actions when a roller revolves in a counter clockwise direction in succession in a rotary compressor in accordance with a preferred embodiment of the present invention, wherein FIG. 4 A illustrates an initial stage of suction, FIG. 4B illustrates a compression and discharge stages, and FIG. 4C illustrates a final stage of discharge.

Following rotation of the crankshaft 40, the roller 80 rolls and revolves along the inside circumferential surface of the cylinder 50 in the counter clockwise direction.

During this process, the suction port 51 is opened, to draw gas into the compression chamber. In this instance, the gas is drawn into the high pressure discharge part 210 with the roller 80 as shown in FIG. 4A.

Next, as the roller 80 keeps rolling, a volume of the high pressure discharge part 210 is reduced, to compress the gas in the high pressure compression part 210.

During this process, the vane 90 makes an elastic up/down movement by the spring 95 and the roller 80, to maintain the high pressure discharge part 210 air tight. At the same time with this, new gas is kept drawn through the suction port 51.

Then, when the high pressure discharge part 210 reaches to a pressure higher than a preset pressure, the discharge valve 110 (see FIG. 1) on the high pressure discharge part 210 side is opened. According to this, the gas starts to be discharged from the high pressure discharge part 210 to the muffler through the discharge port 61 -l ias shown in FIG. 4B.

Then, as the roller 80 revolves continuously, the gas in the high compression part 210 is discharged to the muffler through the discharge port 61, fully. Once the gas is discharged through the discharge port 61 fully, the discharge valve 110 closes the discharge port 61 by means of an elastic force of its own as shown in FIG. 4C.

Then, as the roller 80 revolves in the counter clockwise direction continuously, the gas is discharged to the muffler as the compressor is progressed through the suction, compression and discharge processes.

In the meantime, FIGS. 5A ~ 5C illustrate cross sections showing actions when a roller revolves in a clockwise direction in succession in a rotary compressor in accordance with a preferred embodiment of the present invention, wherein FIG. 5A illustrates a suction starting stage, and FIG. 5B illustrates compression and discharge stages.

As the crankshaft 40 rotates in a reverse direction, the roller 80 rolls on, and revolves along the inside circumferential surface of the cylinder 50 in the clockwise direction. During the process, the suction port 51 is opened, to draw gas into the compression chamber. In this instance, the gas is drawn into the low pressure discharge part 220 with the roller 80 as shown in FIG. 5A.

Next, as the roller 80 keeps revolving, the volume of the low pressure discharge part 220 is reduced, to compress the gas in the low pressure discharge part 220. At the same time with this, new gas is kept drawn through the suction port 51.

Then, when the high pressure discharge part 220 reaches to a pressure higher than a preset pressure, the discharge valve 120 (see FIG. 1) on the low pressure discharge part 220 side is opened. According to this, the gas starts to be discharged from the low pressure discharge part 220 to the muffler through the discharge port 63 as shown in FIG. 5B.

Then, as the roller 80 revolves continuously, the gas in the low compression part 220 is discharged to the muffler through the discharge port 63, fully. Once the gas is discharged through the discharge port 63 fully, the discharge valve 120 closes the discharge port 63 by means of an elastic force of its own, which is, though not shown, similar to FIG. 4C.

Then, as described before, as the roller 80 revolves in the clockwise direction continuously, the gas is discharged to the muffler as the compressor is progressed through the suction, compression and discharge processes. Next, referring to FIG. 1, the compressed gas in the muffler 140 is discharge to an inside space of the case 1 through the discharge opening 141. Then, the gas moves up through spaces between the rotor 30 and the stator 20 or the stator 20 and the case 1.

Thereafter, the compressed gas moves to a destination through the discharge pipe 9.

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 The rotary compressor of the present invention can compress gas regardless of a rotation direction of a crankshaft. In addition to this, the rotary compressor of the present invention has a compression volume varied with a rotation direction of the crankshaft, which is an operation that can not be expected from the related art rotary compressor, and provides the following advantages. First, in the related art, two compressors with different compression capacities and an inverter are combined for implementing dual capacity compression. In this case, the system becomes substantially complicate and the production cost can not but be increase. However, the present invention can implement the dual capacity compression even only with one compressor without the inverter. Particularly, only by changing least number of components from the related art rotary compressor, the dual capacity compression can be implemented.

Second, the related art compressor with single compression capacity can not deal with different operation conditions of air conditioners and refrigerators and the like, appropriately. In this instance, power can not but be wasted, unnecessarily. However, the present invention permits production of compression capacities suitable for operation conditions of appliances.

Claims

What is Claimed is:

1. A rotary compressor comprising: a compression chamber having one suction port and two discharge ports; a rolling member eccentric from a center of the compression chamber, mounted to roll on, and revolve along a wall surface of the compression chamber in either direction, for compressing a portion of a space of the compression chamber; and a dividing member disposed between the discharge ports, and fitted to maintain contact with the rolling member always, for dividing the suction part and the discharge part.

2. The rotary compressor as claimed in claim 1, wherein the compression chamber has a compression volume dependent on a revolving direction of the rolling member.

3. The rotary compressor as claimed in claim 2, wherein the compression volume is constant regardless of the revolving direction of the rolling member.

4. The rotary compressor as claimed in claim 3, wherein the suction port is positioned on an imaginary line passing through the dividing member.

5. The rotary compressor as claimed in claim 2, wherein the compression volume is dependent on the rotation direction of the rolling member.

6. The rotary compressor as claimed in claim 5, wherein the suction port is positioned on either side of the imaginary line passing through the dividing member.

7. The rotary compressor as claimed in claim 6, wherein the suction port is positioned within a range of 180° ~ 300° from the dividing member in any direction.

8. The rotary compressor as claimed in claim 1, wherein the discharge ports are spaced apart at equal distances from the dividing member.

9. The rotary compressor as claimed in claim 1, further comprising opening/closing members for opening the discharge ports when a pressure of the discharge part is higher than a preset pressure.

10. The rotary compressor as claimed in claim 1, further comprising a rotating member for rolling the rolling member in a clockwise or a counter clockwise direction, selectively.

11. The rotary compressor as claimed in claim 10, further comprising bearing members for supporting the rotating member as well as forming the compression chamber.

12. The rotary compressor as claimed in claim 1, further comprising a supporting member for elastic supporting of the dividing member, so that the dividing member is always in contact with the rolling member.

13. A rotary compressor comprising: a reversibly mounted crankshaft having an eccentric part; a cylinder having the eccentric part held therein, a compression chamber formed therein, and a suction port formed therein so as to be in communication with the compression chamber; a bearing fitted to form the compression chamber together with the cylinder, and rotatably supporting the crankshaft, the bearing having two discharge ports each in communication with the compression chamber; discharge valves for opening the discharge ports when a pressure inside of the compression chamber is higher than a preset pressure; a roller rotatably provided to the eccentric part for rolling along an inside circumferential surface of the cylinder; and a vane elastically fitted to the cylinder so as to be positioned between the discharge ports, for keeping contact with the roller always to divide the compression chamber into a suction part and a discharge part.

14. The rotary compressor as claimed in claim 13, wherein the compression chamber has a compression volume dependent on a rotation direction of the crankshaft.

15. The rotary compressor as claimed in claim 14, wherein the compression volume is constant regardless of the rotation direction of the crankshaft.

16. The rotary compressor as claimed in claim 15, wherein the suction port is positioned on an imaginary line passing through the vane.

17. The rotary compressor as claimed in claim 14, wherein the compression volume is dependent on the rotation direction of the crankshaft.

18. The rotary compressor as claimed in claim 17, wherein the suction port is positioned on either side of the imaginary line passing through the vane.

19. The rotary compressor as claimed in claim 18, wherein the suction port is positioned within a range of 180° ~ 300° from the vane in any direction.

20. The rotary compressor as claimed in claim 18 or 19, wherein the discharge part includes; a low pressure discharge part having a relatively short distance from the suction port to the vane, and a high pressure discharge part having a relatively long distance from the suction port to the vane.

21. The rotary compressor as claimed in claim 13, further comprising a spring having one end fixed to the cylinder and the other end joined with the vane, for pushing the vane toward the roller.

22. The rotary compressor as claimed in claim 13, wherein the suction port is formed in a direction perpendicular to the crankshaft.

23. The rotary compressor as claimed in claim 13, further comprising retainers provided to come into contact with the discharge valves, for limiting an extent of opening of the discharge valve.

24. The rotary compressor as claimed in claim 13, further comprising a muffler provided to be in communication with the discharge ports, for reducing discharge noise.