SCROLL COMPRESSOR WITH SUPPORTING MEMBER IN AXIAL DIRECTION

Abstract

A scroll compressor includes a case, a fixed scroll having a fixed wrap, and an orbiting scroll having an orbiting wrap coupled to the fixed wrap to define compression chambers. A driving motor has a crankshaft, the crankshaft having one end portion coupled to the orbiting scroll, a main frame and an auxiliary frame fixed onto an inner wall of the case to support the crankshaft, respectively, and a thrust plate having an annular shape and interposed between the auxiliary frame and the crankshaft to support the crankshaft in an axial direction, wherein a plurality of oil channels are formed on a surface of the thrust plate so as to communicate an inside and an outside of the thrust plate with each other.

Description

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims priority under 35 U.S.C. §119 to Korean Application No. 10-2011-0101494 filed in Korea on Oct. 5, 2011, which is hereby incorporated by reference for all purposes as if fully set forth herein

TECHNICAL FIELD

The present disclosure relates to a scroll compressor having a supporting member in an axial direction, and more particularly, a scroll compressor having a member for axially supporting a crankshaft to which a rotor of the scroll compressor is fixed.

BACKGROUND ART

In general, a scroll compressor is a compressor for compressing refrigerant gas by varying volumes of compression chambers formed by a pair of scrolls which face each other. The scroll compressor is being widely used, especially, in an air conditioner, in the aspects of higher compression efficiency, lower vibration and noise, a more reduced size and a lighter weight, as compared to a reciprocal compressor or a rotary compressor.

FIG. 1 is a sectional view schematically showing one exemplary embodiment of a scroll compressor. As shown in FIG. 1, the scroll compressor includes a case 1 having an inner space which is divided into a suction space 11 as a low pressure part and a discharge space 12 as a high pressure part, a driving motor 2 installed in the suction space 11 of the case 1 to generate a rotational force, and a main frame 3 fixed between the suction space 11 and the discharge space 12 of the case 1. A fixed scroll 4 is fixed onto an upper surface of the main frame 3. An orbiting scroll 5, which forms two pairs of consecutively moving compression chambers P together with the fixed scroll 4, is installed to orbit between the main frame 3 and the fixed scroll 4 by being eccentrically coupled to a crankshaft of the driving motor 2. An Oldham ring 6 for preventing self-rotation of the orbiting scroll 5 is installed between the fixed scroll 4 and the orbiting scroll 5.

A suction pipe 13 is coupled to communicate with the suction space 13 of the case 1, and a discharge pipe 14 is coupled to communicate with the discharge space 12.

The driving motor 2 includes a stator 21 fixed onto an inner surface of the case 1, and a rotor 22 located inside the stator 21 and coupled to the crankshaft 23. In addition, a lower end portion of the crankshaft 23 is supported by an auxiliary frame 7.

In the scroll compressor having the structure, the crankshaft 23 is supported in a radial direction by the main frame 3 and the auxiliary frame 7 which are located at both sides of the crankshaft 23 based on the rotor 22, and supported by the auxiliary frame 7 in an axial direction. In general, to the crankshaft of the scroll compressor is applied a rotational force in response to rotation of the driving motor and a compression force of gas, which is repulsive to the rotational force. Namely, forces in a radial direction are generally applied to the crankshaft. Accordingly, journal bearings may be provided at the main frame and the auxiliary frame to support the crankshaft for smooth operation.

However, in recent time, a type of scroll compressor which controls a rotating speed of the driving motor is widely used. This inverter control type scroll compressor exhibits a high rotating speed variation width of the crankshaft and sets a top speed to be higher than that of the related art scroll compressor. This structure further requires an element for supporting the crankshaft more stably in the axial direction.

DISCLOSURE OF THE INVENTION

Therefore, to obviate those problems, an aspect of the detailed description is to provide a scroll compressor having a supporting member capable of stably supporting a crankshaft in an axial direction.

To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is provided a scroll compressor including a case, a fixed scroll having a fixed wrap, an orbiting scroll having an orbiting wrap coupled to the fixed wrap to define compression chambers, the orbiting scroll performing an orbiting motion with respect to the fixed scroll, a driving motor having a crankshaft, the crankshaft having one end portion coupled to the orbiting scroll, a main frame and an auxiliary frame fixed onto an inner wall of the case to support the crankshaft, respectively, and a thrust plate having an annular shape and interposed between the auxiliary frame and the crankshaft to support the crankshaft in an axial direction, wherein a plurality of oil channels may be formed on a surface of the thrust plate so as to communicate an inside and an outside of the thrust plate with each other.

In the aspect of the present disclosure, the scroll compressor may further include the thrust plate for supporting the crankshaft in the axial direction, which may result not only in supporting of the crankshaft in the axial direction but also in reduction of a frictional force generated due to an axial rotation of the crankshaft. Especially, the oil passages may be formed on the surface of the thrust plate to allow oil to be smoothly supplied onto a frictional surface between the crankshaft and the thrust plate, thereby improving lubrication performance. Here, the oil passages may connect an outer circumferential surface and an inner circumferential surface of the thrust plate, namely, communicate inside and outside of the thrust plate with each other, so that oil existing at the outer circumferential surface of the thrust plate can smoothly circulate through the oil passages. This may result in reduction of damage due to an introduction of foreign materials and simplification of a fabricating process.

Here, the plurality of oil channels may have a linear shape or a cylindrical shape.

Each of the plurality of oil channels may extend to be inclined with respect to a radial direction of the annular thrust plate, to allow oil existing at the outer circumferential surface of the thrust plate to be smoothly introduced.

The oil channels may be formed to allow oil existing outside the thrust plate to be introduced to an inside of the thrust plate in response to rotation of the crankshaft. As one example, if it is assumed that an end of each oil passage located outside the thrust plate is an inlet port and another end thereof located inside the thrust plate is an outlet port, the outlet port may located by being spaced apart from the inlet port by a predetermined angle on a circumference with respect to a rotating direction of the crankshaft. Accordingly, the oil can be introduced along the rotating direction of the crankshaft and smoothly flow along the oil passages due to a frictional force against the crankshaft, thereby facilitating the oil circulation.

In the meantime, for more smooth oil supply, the thrust plate may be located lower than an appropriate minimum oil level.

A protrusion which is inserted into a stopping groove formed at the auxiliary frame may be formed at an outer circumferential portion of the thrust plate. This may prevent the thrust plate from rotating together with the crankshaft, resulting in prevention of lowering of lubrication performance.

In accordance with another exemplary embodiment of the present disclosure, there is provided a scroll compressor including a case, first and second supporting units fixed to the case, a crankshaft rotatably supported by the first and second supporting units, the crankshaft having a facing surface facing the second supporting unit in an axial direction, a driving motor to rotate the crankshaft, a compression unit coupled to the crankshaft to compress fluid, and a thrust bearing member located between the facing surfaces of the crankshaft and the second supporting unit, wherein the thrust bearing member may include an oil introduction element disposed to be sunk in lubricating oil and configured to allow the lubricating oil to be introduced between frictional surfaces in response to rotation of the crankshaft.

In accordance with the aspects of the present disclosure, a thrust plate for supporting a crankshaft in an axial direction may further be provided so as to support the crankshaft in the axial direction and also reduce a frictional force generated due to an axial rotation. Especially, oil passages may be formed on a surface of the thrust plate so as to allow oil to be smoothly supplied onto a frictional surface between the crankshaft and the thrust plate, resulting in improving of a lubrication performance. Here, the oil passages may connect an outer circumferential surface and an inner circumferential surface of the thrust plate, namely, communicate inside and outside of the thrust plate with each other, so that oil existing at the outer circumferential surface of the thrust plate can smoothly circulate through the oil passages. This may result in reduction of damage due to an introduction of foreign materials and simplification of a fabricating process.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view showing an inner structure of a general scroll compressor according to the related art;

FIG. 2 is a sectional view showing an inner structure of a scroll compressor in accordance with one exemplary embodiment of the present disclosure;

FIG. 3 is an enlarged sectional view showing a lower part of the scroll compressor shown in FIG. 2;

FIG. 4 is a partially cut perspective view showing a portion where a thrust plate is mounted in the scroll compressor shown in FIG. 2;

FIG. 5 is a planar view of the thrust plate shown in FIG. 2;

FIG. 6 is a planar view showing another exemplary embodiment of a thrust plate; and

FIG. 7 is a graph showing a variation of an input reduction according to a type of thrust plate.

MODES FOR CARRYING OUT THE PREFERRED EMBODIMENTS

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings where those components are rendered the same reference number that are the same or are in correspondence, regardless of the figure number, and redundant explanations are omitted. In describing the present invention, if a detailed explanation for a related known function or construction is considered to unnecessarily divert the gist of the present invention, such explanation has been omitted but would be understood by those skilled in the art. The accompanying drawings are used to help easily understood the technical idea of the present invention and it should be understood that the idea of the present invention is not limited by the accompanying drawings. The idea of the present invention should be construed to extend to any alterations, equivalents and substitutes besides the accompanying drawings.

Hereinafter, description will be given in detail of the exemplary embodiments of a scroll compressor having a supporting member in an axial direction, with reference to the accompanying drawings.

FIG. 2 is a sectional view showing an inner structure of a scroll compressor in accordance with one exemplary embodiment of the present disclosure, and FIG. 3 is an enlarged sectional view showing a lower part of the scroll compressor shown in FIG. 2. As shown in FIGS. 2 and 3, a scroll compressor 100 according to the one exemplary embodiment may include a case 110 having a hermetic inner space, a compression unit 121 installed within the case 110 to compress a refrigerant, and a driving motor 141 installed within the case 110 to provide a driving force to the compression unit 121.

At one side of the case 110 may be provided a suction pipe 111 and a discharge pipe 113 for allowing introduction and discharge of a refrigerant, respectively. The compression unit 121 may be installed at an upper part within the case 110. The compression unit 121 may include a fixed scroll 123 having an involute wrap 125 and fixed into the case 110, and an orbiting scroll 133 coupled to orbit with respect to the fixed scroll 123 and having an involute wrap 135.

The driving motor 141 may include a stator 143 fixed into the case 110, and a rotor installed within the stator 143 to be rotatable based on the crankshaft 147. An eccentric portion 148 for driving the orbiting scroll 133 may be formed at an upper region of the crankshaft 147. A thrust surface 149 for supporting the crankshaft 147 in an axial direction may be formed at a lower region of the crankshaft 147. A main frame 151 and an auxiliary frame 161 for rotatably supporting the crankshaft 147 may be installed at the upper region and the lower region of the crankshaft 147, respectively.

An upper bearing 153 for rotatably supporting an upper portion of the crankshaft 147 in an accommodating manner may be formed at a central region of the main frame 151. The auxiliary frame 161 may have a shape of a triangular case whose top is open. A coupling opening 163 in which a lower bearing member 201 is accommodated may penetrate through a central region of a lower portion of the auxiliary frame 161. A nut 164 to which a fixing bolt 177 is coupled may be formed at a periphery of the coupling opening 163.

The lower bearing member 201 may include a flange portion 203 having a triangular shape to be received in the auxiliary frame 161, and a cylindrical portion 213 formed at a lower side of the flange portion 203 and having a cylindrical shape. A radial bearing portion 215 and a thrust bearing portion 217 may be formed in the cylindrical portion 213 so as to support the crankshaft 147 in a radial direction and an axial direction, respectively. A bolt opening 205 may be formed at the flange portion 203 to allow the flange portion 203 to be integrally coupled to the auxiliary frame 161 by the fixing bolt 177.

In the meantime, a thrust plate 221 having an annular shape may be coupled between the crankshaft 147 and the thrust bearing portion 217. Accordingly, the thrust plate 221 may contact the crankshaft 147 to prevent abrasion of the thrust bearing portion 217. A protrusion 223 may protrude outwardly from one side of the thrust plate 221 in a radial direction. A stopping groove 218 in which the protrusion 223 is inserted may be formed at the lower bearing member 201. The protrusion 223 may be inserted into the stopping groove 218 so as to prevent the thrust plate 221 from rotating by itself in response to rotation of the crankshaft 147.

The thrust plate 221 may be located lower than an appropriate minimum oil level represented by h_min in FIG. 3. This may allow the thrust plate 221 to always be sunk in oil, resulting in further improvement of lubrication performance.

As shown in FIG. 5, the thrust plate 221 may include a plate main body 222 having an annular shape, and the protrusion 223 protruding from one side of the plate main body 222. A plurality of oil channels 224 may be formed at the surface of the plate main body 222. FIG. 5 exemplarily shows totally 8 oil channels 224, but the total number may be randomly set according to a diameter or the like of the plate. The oil channels 224 may have a linear shape and be inclined with respect to a radial direction of the plate main body 222.

Here, an inclined direction of the oil channels 224 may be decided such that an oil inlet port 224a is located more behind an oil outlet port 224b on a circumference, with respect to a rotating direction of the crankshaft 147 indicated by an arrow. Accordingly, oil existing at an outer circumferential portion of the plate main body 222 can be smoothly introduced into an inner circumferential portion of the plate main body 222. The oil channel 224 may extend to cross an outer circumferential surface and an inner circumferential surface of the plate main body 222, and for the sake of explanation, it is referred to as an open type channel.

The presence of the oil channels may allow oil to be smoothly introduced between the thrust surface 149 and the plate main body 222 so as to be evenly provided onto a contact surface. Also, pressure generated by the introduced oil can be applied to the thrust surface 149 to push the crankshaft 147 up. This may result in further reduction of a frictional force.

Without limit to the structure of the oil channel, an oil channel, as shown in FIG. 6, may be formed to be close to an inner circumferential surface of a plate main body without contacting each other. This is referred to as a closed type channel. Upon employing this closed type channel, introduced oil cannot be discharged and accordingly stronger oil pressure than the open type channel can be applied. However, in the closed type channel, when a chip generated due to friction or other foreign materials are introduced, those things may not be discharged immediately, which may cause a contact surface to be damaged.

FIG. 7 is a graph showing a variation of an input reduction according to a type of oil channel. Types of oil channels represented by A to C are as follows.

	Type	Number	Width (mm)	Depth (mm)
A	Closed	12	1	0.1
B	Closed	8	1.5	0.25
C	Open	8	1.5	0.25

As shown in FIG. 7, it can be understood that the open type C exhibits the highest input reduction at an entire range of a rotating speed. Especially, it can be noticed that as a width and a depth increase more, more oil flows and consequently the input reduction increases. It can also be noticed through comparison of the oil channels B and C which have the same size and number, the open type C is more advantageous than the closed type B in view of the input reduction.

Claims

1. A scroll compressor comprising a case;

a fixed scroll having a fixed wrap;

an orbiting scroll having an orbiting wrap coupled to the fixed wrap to define compression chambers, the orbiting scroll performing an orbiting motion with respect to the fixed scroll;

a driving motor having a crankshaft, the crankshaft having one end portion coupled to the orbiting scroll;

a main frame and an auxiliary frame fixed onto an inner wall of the case to support the crankshaft, respectively; and

a thrust plate having an annular shape and interposed between the auxiliary frame and the crankshaft to support the crankshaft in an axial direction,

wherein a plurality of oil channels are formed on a surface of the thrust plate so as to communicate an inside and an outside of the thrust plate with each other.

2. The compressor of claim 1, wherein the plurality of oil channels have a linear shape.

3. The compressor of claim 2, wherein each of the plurality of oil channels extends to be inclined with respect to a radial direction of the annular thrust plate.

4. The compressor of claim 1, wherein the oil channels are formed to allow oil existing outside the thrust plate to be introduced to an inside of the thrust plate in response to rotation of the crankshaft.

5. The compressor of claim 4, wherein if it is assumed that an end of each oil passage located outside the thrust plate is an inlet port and another end thereof located inside the thrust plate is an outlet port, the outlet port is located by being spaced apart from the inlet port by a predetermined angle on a circumference with respect to a rotating direction of the crankshaft.

6. The compressor of claim 1, wherein the thrust plate is located lower than an appropriate minimum oil level.

7. The compressor of claim 1, wherein a protrusion is formed at an outer circumferential portion of the thrust plate so as to be inserted into a stopping groove formed at the auxiliary frame.

8. A scroll compressor comprising:

a case;

first and second supporting units fixed to the case;

a crankshaft rotatably supported by the first and second supporting units, the crankshaft having a facing surface facing the second supporting unit in an axial direction;

a driving motor to rotate the crankshaft;

a compression unit coupled to the crankshaft to compress fluid; and

a thrust bearing member located between the facing surfaces of the crankshaft and the second supporting unit,

wherein the thrust bearing member comprises an oil introduction element disposed to be sunk in lubricating oil and configured to allow the lubricating oil to be introduced between frictional surfaces in response to rotation of the crankshaft.

9. The compressor of claim 8, wherein the thrust bearing member is fixed to the second supporting unit to be prevented from being rotated.

10. The compressor of claim 8, wherein the oil introduction element comprises a plurality of oil channels formed on a surface of the thrust bearing member.

11. The compressor of claim 10, wherein the thrust bearing member has an annular shape, and the oil channels extend to communicate inside and outside of the thrust bearing member with each other.

12. The compressor of claim 11, wherein the plurality of oil channels have a linear shape.

13. The compressor of claim 12, wherein each of the plurality of oil channels extends to be inclined with respect to a radial direction of the thrust plate.

14. The compressor of claim 11, wherein if it is assumed that an end of each oil passage located outside the thrust plate is an inlet port and another end thereof located inside the thrust plate is an outlet port, the outlet port is located by being spaced apart from the inlet port by a predetermined angle on a circumference with respect to a rotating direction of the crankshaft.