Title of Invention	"RECIPROCATING COMPRESSOR"
Abstract	A reciprocating compressor includes a driving unit (16) having an outer stator (26) and an inner stator disposed at a predetermined air gap there between, and a moving member positioned between the outer stator (26) and the inner stator (28) and linearly and reciprocally moved; a compression unit (18) having a cylinder (38) fixed at an inner circumferential surface of the inner stator (28) and a piston (22) linearly moved in the cylinder (38) by being connected to the moving member; a support portion (20) supporting the compression unit (18) and the driving unit (16); and a resonant spring unit positioned (24) at a rear portion of the driving unit (16), disposed at the support portion (20), and inducing a resonant movement of the piston (22). Therefore, a resonant spring (62,64) of the compressor can be moved horizontally and straight forwardly by reducing a torsion moment of the resonant spring (62,64), a width of the compressor can be reduced, and a concentricity of a driving unit (16) and a compression unit can be maintained.

Title of Invention

"RECIPROCATING COMPRESSOR"

Abstract

A reciprocating compressor includes a driving unit (16) having an outer stator (26) and an inner stator disposed at a predetermined air gap there between, and a moving member positioned between the outer stator (26) and the inner stator (28) and linearly and reciprocally moved; a compression unit (18) having a cylinder (38) fixed at an inner circumferential surface of the inner stator (28) and a piston (22) linearly moved in the cylinder (38) by being connected to the moving member; a support portion (20) supporting the compression unit (18) and the driving unit (16); and a resonant spring unit positioned (24) at a rear portion of the driving unit (16), disposed at the support portion (20), and inducing a resonant movement of the piston (22). Therefore, a resonant spring (62,64) of the compressor can be moved horizontally and straight forwardly by reducing a torsion moment of the resonant spring (62,64), a width of the compressor can be reduced, and a concentricity of a driving unit (16) and a compression unit can be maintained.

Full Text	The present invention relates to a reciprocating compressor, and particularly to a reciprocating compressor that can be compact in size and having improved performance. BACKGROUND ART Figure 1 is a sectional view showing a reciprocating compressor in accordance with one example of a conventional art. A conventional reciprocating compressor includes a close casing to which a suction pipe 102 and a discharge pipe 104 are connected respectively; a driving unit 108 disposed in the casing 106 and generating a reciprocal movement force; a compression unit 110 transmitted the reciprocal movement force generated at the driving unit 108 and compressing a fluid; a support portion 112 supporting the driving unit 108 and the compression unit 110. The driving unit 108 includes an outer stator 116 fixed at the support portion 112 and having a winding coil 114 to which power is applied; an inner stator 118 disposed at an inner circumferential surface of the outer stator 116 with a predetermined air gap therebetween; a magnet 120 positioned at the air gap between the outer stator 116 and the inter stator 118 and linearly and reciprocally moved when power is applied to the winding coil 114; and a moving member 122 mounted to the magnet 120 at a same interval in a WO 2005/033509 PCT/KR2003/002054 2 circumferential direction and transmitting a linear movement of the magnet 120 to the piston 124 by being coupled with a piston 124 of. the compression, unit 110. The compression unit 110 includes a piston 124 linearly and reciprocally moved by being coupled with the moving member 122; a cylinder 130, in which the piston 124 is slidably inserted, having a compression chamber; and a suction valve 132 installed at a front portion of the piston 124 to prevent the fluid introduced into the compression chamber from being flowed backwardly; a discharge valve assembly 134 installed at a front portion of the cylinder 130 to perform an open-and-shut action of a discharged fluid. The support unit 112 includes a first frame 140 to which the inner stator 118 is fixed, mounted to an outer circumferential surface of the cylinder 130, and supporting one side surface of the outer stator 116; a second frame 142 supporting the other side surface of the outer stator 116; a third fame 144 coupled with the second frame 142 and receiving a resonant spring unit 146, The resonant spring unit 146 for inducing a resonant movement of the piston 124, includes a first resonant spring 148 interposed between the first frame and one side surface of a connecting portion 152 between the moving member 122 and the piston 124, and providing an elastic force to the piston 124 when the piston 124 is rearwardly moved; and second resonant spring 150 interposed between the other side surface of the connecting portion 152 and the third frame 144, and providing an elastic force to the piston 124 when the piston 124 is forwardly moved in order to compress a fluid. Herein, the first resonant spring 148 and the second resonant spring WO 2005/033509 PCT/KR2003/002054 3 150 are formed of a compression coil spring. The first resonant spring 148 has a bigger diameter than an outer diameter of the cylinder 130 and positioned at the outer circumferential surface of the cylinder 130, and the second resonant spring 150 is positioned at a rear portion of the compression unit 110. In the convention reciprocating compressor, when power is applied to a winding coil 114, a flux is formed between the outer stator 115 and the inner stator, and thus the magnet 120 and the moving member 122 are linearly and reciprocally moved. While the piston 124 connected to the moving member 122 is linearly and reciprocally moved in the cylinder 130, a fluid is compressed. At this time, when the piston 124 forwardly moves to compress a fluid, an elastic force of a second resonant spring 150 is provided to the piston 124, and when moving rearwardly, an elastic force of a first resonant spring 148 is provided to the piston 124. However, in the conventional reciprocating compressor, the first resonant spring 148 is positioned in a space between an outer circumferential surface of the cylinder 130 and an inner circumferential surface of the inner stator 118. Accordingly, a width of a compressor should be big because a predetermined space should be secured to install the first resonant spring 148 between the outer circumferential surface of the cylinder 130 and the inner stator 118. Also, since the first and the second springs 148 and 150 are formed of a compression coil spring having a torsion moment, and are disposed at the both sides of a connection unit 152 between the moving member 122 and the WO 2005/033509 PCT7KR2003/002054 4 piston respectively, the torsion moment occurs while the first and the second springs 148 and 150 repeatedly compress and expand. Because of this, it is difficult for the piston 124 to keep its linear movement, so performance of a motor is deteriorated. Figure 2 is a sectional view showing a reciprocating compressor for solving those problems according to another example of the conventional art. In a reciprocating compressor shown in Figure 2, a compression unit 110 is disposed at a front portion of a casing 106 and fixed at a first frame 162, and a driving unit 108 is disposed at a rear portion of the casing 106, and fixed at second and third frames 164 and 166. A moving member 122 of the driving unit 108 and a piston 124 are connected mechanically and a spring supporting member is disposed at a connection portion of the moving member 122 and the piston 124. Also, plural first resonant springs 172 are disposed between the first frame 162 and a front portion surface of the spring supporting member 176 at a predetermined interval in a circumferential direction. Plural second resonant springs 174 are disposed between a rear portion surface of the spring supporting member 176 and the second frame at a predetermined interval in a circumferential direction. In the reciprocating compressor, a width of the compressor 110 can be reduced since the driving unit 108 and the compression unit 110 are positioned at front and rear portions of the casing 106 respectively and the first resonant spring 172 and the second resonant spring 174 are disposed at an outer circumferential portion of the compression 110. Also, since; the plural WO 2005/033509 PCT/KR2003/002054 5 first and second resonant springs 172 and 174 are disposed in a circumferential direction, a torsion moment caused by repeated compression and expansion of the springs can be reduced. However, in the reciprocating compressor according to the conventional art, the driving unit 108 generating a reciprocal movement force and the compression unit 110 transmitted the movement force from the driving unit 108 are disposed at the front portion and at rear portions of the compressor at a predetermined interval. Accordingly, it is difficult to adjust a concentricity of the driving unit 109 and the compression unit 110, and thus degrading of assembling is caused. That is, even though a concentricity of the inner and outer stators 116 and 118 of the driving unit 108 has been adjusted, a concentricity of the driving unit 108 and the piston 124 of the compression unit 110 has to be adjusted again, and thus a difficulty of assembling is caused. In addition, since the driving unit 108 and the compression unit 110 are disposed at the front and rear portions of the casing 106 respectively, the concentricity of the piston 124 is severely deviated even though the concentricity of the moving member 122 is little bit deviated during an operation of the compressor. This causes a collision of the cylinder 130 and the piston 124 and, accordingly, performance of the compressor is deteriorated. DISCLOSURE OF THE INVENTION Therefore, it is an object of the present invention to provide a WO 2005/033509 PCT/KR2003/002054 6 reciprocating compressor capable of moving a resonant spring horizontally and straight forwardly by reducing a torsion moment of the resonant spring, reducing a width of the compressor, and maintaining a concentricity of a driving unit and a compression unit. To achieve the above objects, there is provided a reciprocating compressor including a driving unit having an outer stator and an inner stator disposed at a predetermined air gap therebetween, and a moving member positioned between the outer stator and the inner stator and linearly and reciprocally moved; a cylinder fixed at an inner circumferential surface of the inner stator; a compression unit coupled with the moving member and linearly and reciprocally moved in the cylinder; a support unit for supporting the compression unit and the driving unit; a resonant spring unit disposed at a rear portion of the driving unit, disposed at the support portion and inducing a resonant movement of the piston.. The cylinder is fixed at the inner circumferential surface of the inner stator by a press-fit method. The support unit includes a first frame supporting an outer circumferential surface of the cylinder and one side surface of each of outer stator and inner stator; a second frame supporting the other side surface of the outer stator; a third frame coupled with the second frame and receiving the resonant spring unit. The resonant spring unit includes a spring support member mounted to a portion where the piston and moving member are connected; plural first resonant springs disposed between the second frame and one side surface of WO 2005/033509 PC17KR2003/002054 7 the spring support member; plural second resonant springs disposed between the third frame and the other side surface of the spring support member. The spring support member includes a coupling portion coupled with a portion where the moving member and the piston are connected, and disposed at a rear portion of the piston; a first support portion where the first resonant spring is supported, prolonged from an edge of the coupling portion at a predetermined interval in a circumferential direction; a second support portion where the second resonant spring is supported, disposed between the first support portions BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a sectional view showing a reciprocating compressor in accordance with one example of the conventional art. Figure 2 is a sectional view showing a reciprocating compressor in accordance with another example of the conventional art. Figure 3 is a sectional view showing a reciprocating compressor in accordance with one embodiment of the present invention. Figure 4 is a sectional view showing a state that an inner stator of a reciprocating compressor and a cylinder are coupled in accordance with the present invention. Figure 5 is a sectional view taken along line V-V of Figure 4. Figure 6 is a perspective view showing a resonant spring unit of a reciprocating compressor in accordance with the present invention. Figure 7 is a side view showing a disposition state of resonant springs WO 2005/033509 PC17KR2003/002054 8 of a reciprocating compressor in accordance with the present invention. Figures 8 and 9 are partial sectional views showing a fixing state of a resonant spring in accordance with the present invention. Figures 10 and 11 are front views showing a winding direction of a resonant spring of a reciprocating compressor in accordance with the present invention. MODES FOR CARRYING OUT THE PREFERRED EMBODlMiENTS A first embodiment of the present invention will now be described with reference to the accompanying drawings. There can be a plurality of embodiments of the reciprocating compressor in accordance with the present invention, and a preferred embodiment will now be described. Figure 3 is a sectional view of a reciprocating compressor according to the present invention. The reciprocating compressor of the present invention includes a casing 14 to which a suction pipe 10 and a discharge pipe12 are connected respectively; a driving unit 16 disposed in the casing 14 and generating a reciprocal movement force; a compression unit 18 disposed in the driving unit 16 and compressing a fluid by being transmitted the reciprocal movement force of the driving unit 16; a support unit 20 supporting the driving unit 16 and the compression unit 18; a resonant spring assembly 24 installed at the support unit 20 and inducing a resonant movement of the piston 22 by providing an elastic force to the piston 22 of the compression unit 18. WO 2005/033509 PCT/KR2003/002054 9 The driving unit 16 includes an outer stator 26 fixed at the support portion 20; an inner stator 28 disposed between itself and an inner circumferential surface of the outer stator 26 at a predetermined air gap; a winding coil 30 to which power is applied, disposed at one of the outer stator 28 and the inner stator 28; a magnet 32 installed at the air gap between the outer stator 26 and the inner stator 28, and linearly and reciprocally moved when power is applied to the winding coil 30; a moving member 34 at which the magnet 32 is fixed at a same interval in a circumferential direction, transmitting a linear movement of the magnet to the piston 22 by being coupled with the piston 22 of the compression unit 18. The compression unit 18 includes a cylinder 38 fixed at the inner circumferential surface of the inner stator 28, and having a compression chamber 36 in which a fluid is compressed; a piston 22 linearly and movably inserted in the cylinder 38, coupled with the moving member 34, linearly moved when the moving member 32 is linearly moved, thereby compressing a fluid in the compression chamber 36; a suction valve 40 mounted to a front portion of the piston 122 to prevent the fluid introduced into the compression chamber from being flowed backwardly; a discharge valve assembly 42 disposed.at a front portion of the cylinder 38 to perform an open-and-shut action of a discharged fluid. Herein, as shown in Figures 4 and 5, the cylinder 38 is fixed at the inner circumferential surface of the inner stator 28 by a press-fit method or the like. That is, since the cylinder is directly fixed at the inner circumferential surface of the inner stator 28 and thus there is no gap therebetween, a width of the WO 2005/033509 PCT/KR2003/002054 10 compressor can be reduced. The support unit 20 includes a first frame 46 mounted to the outer circumferential surface of the cylinder 38, and supporting one side surface of the outer stator 26; a second frame 48 supporting the other side surface of the outer stator 26; a third frame 50 coupled with the second frame 48 and receiving a resonant spring unit 24. In the first frame 46, an outer circumferential surface of the cylinder 38 is supported at the inner circumferential surface of the first frame 46 by the press-fit method or the like, one side surface of the inner stator 28 is supported at its inner side surface, and one side surface of the outer stator 26 is supported at its outer side surface. In the second frame 48, the other side surface of the outer stator 26 is supported at one side surface of the second frame 48. At the outer side surface of the second frame 48, the third frame 50 is fixed, and springs of the resonant spring unit 24 are supported. In the cylindrical-shaped third frame 50, its one end is fixed at the second frame 48, and prolonged at a certain length toward the rear portion of the casing 14. A fluid passage 52 through which a fluid taken into the inlet 10 passes, is formed at the other end of the third frame 50, and springs of the resonant spring unit 24 are supported at its inner surface. As shown in Figure 6, the resonant spring unit 24 includes a spring support member 60 mounted to a portion where the piston 22 and the moving member 34 are connected; a first resonant spring 62 disposed between the second frame 48 and one side surface of the spring support member 60, and WO 2005/033509 PCT/KR2003/002054 11 providing an elastic force to the piston 22 when the piston moves rearwardly; a second resonant spring 64 disposed between the inner surface of the third frame 50 and the other side surface of the spring support member 60 and providing an elastic force to the piston 22 when the piston moves forwardly. Herein, the spring support member 60 includes a coupling portion 66 positioned at the rear portion of the piston 22 and fixed at a portion where the moving member 34 and the piston 22 are coupled; plural first support portions 68 prolonged from the edge of the coupling portion 66 at a certain interval in a circumferential direction and supporting the first resonant springs 62; second support portions 70 positioned between the first support portions 68, and supporting the second resonant spring 64. The disc-shaped coupling portion 66 has a passage 75 through which a fluid passes, at its center portion. The first support portion 68 is rearwardly prolonged from the edge of the coupling portion 66 at a certain length, and is outwardly bent at its end portion so as to install the first resonant springs 62. Plural first support portions 68 are formed at a certain interval in a circumferential direction of the coupling portion 66. The second support portions 70 are disposed between the first support portions 68 respectively, are radially prolonged from the edge of the coupling portion 66, and thus support the second resonant springs 64. In the first resonant spring 62, its both end portions are supported at the second frame 48 and at the first support portion 68 of the spring support member 60 respectively. In the second resonant spring 64, its both end portions are supported at the third frame 50 and at the second support portion WO 2005/033509 PCT/KR2003/002054 12 70 of the spring support member 60 respectively. Because of these, as shown in Figure 7, when the compressor is viewed from the side, the first resonant spring 62 and the second resonant spring 64 have an overlap section (L). Since the first resonant spring 62 and the second resonant spring 64 have the overlap section (L) in an axial direction of the compressor, a length in the axial direction of the compressor can be reduced. In a different example of the spring support member 60, an overlap section of the first resonant spring 62 and the second resonant spring 64 can be extended more by forming the second support portion to be bent. As shown in Figure 8, spring sheet portions 80 for supporting the first and the second resonant springs are formed at side surfaces of the first and the second support portions 68 and 70 respectively. The cylinder-shaped spring sheet portions 80 are prolonged from the side surfaces of the first and the second support portions 68 and 70 and support the first and the second resonant springs 62 and 64 respectively. Figure 9 shows a special spring sheet member 82 mounted to each of the first and the second support portions 68 and 70 to support the first and the second resonant springs 62 and 64. The spring sheet member 82 consists of a fixing portion 84 inserted and fixed at a through hole 88 formed in each one of the first and the second resonant springs 62 and 64 by a press fit method or the like; and a sheet portion 86 prolonged from the fixing portion 84 and supporting the first and the second resonant springs 62 and 64. The first and the second resonant springs 62 and 64 are formed of compression coil springs respectively, and offsetting torsion moments of each WO 2005/033509 PCT/KR2003/002054 13 other by having an opposite winding direction. As shown in Figure 10, that is, as shown in Figure 10, if the first resonant spring supported at the first support portion 68 is wound counterclockwise as the arrow P, the second resonant spring 64 disposed neighboring on the first resonant spring 62 is wound clockwise as the arrow Q. As shown in Figure 11, the winding directions of the first resonant springs 62 disposed to face each other are different with each other, and the winding directions of the second resonant springs 64 disposed to face each other are different with each other, too. That is, if one first resonant: spring 62 is wound in a direction of the arrow S, the other neighboring first resonant spring 62 is wound in a direction of the arrow T. Also, if one second resonant spring 64 is wound in a direction of the arrow T, the other neighboring second resonant spring 64 is wound in a direction of the arrow S. Operations and effects of the reciprocating compressor will now be described. When power is applied to a winding coil 30, a flux is formed between an outer stator 26 and an inner stator 28. By the flux, a moving member 34 is linearly and reciprocally moved, and thus a piston 22 connected to the moving member 34 compresses and discharge a fluid introduced into a compression chamber while being moved linearly and reciprocally in a cylinder 34, At this time, when the piston 22 moves forwardly to compress a fluid, an elastic force of a second resonant spring 62 is provided to the piston 22, and when the piston 22 moves rearwardly, an elastic force of a first resonant spring 64 is provided to the piston 22, WO 2005/033509 PCT7KR2003/002054 14 In the reciprocating compressor in accordance with the present invention, a width of the compressor can be reduced since a piston is directly fixed at the inner circumferential surface of the inner stator by a press-fit method or the like. An interval in a longitudinal direction between a moving member and a piston can be minimized by positioning the piston in a moving member, whereby a concentricity of the moving member and the piston can be easily adjusted during assembling, and an attrition of the piston and the cylinder and a collision of the moving member and the outer/inner stators are prevented. A length in an axial direction of the compressor can be reduced by disposing first and second resonant springs so as to overlap at a certain section. And, the plural first and second resonant springs are disposed in a circumferential direction, and their winding directions are arranged to be opposite with each other. Accordingly, since a torsion moment, which may occurs while each resonant spring compresses and expands, is prevented, a torsion of the piston and an attrition of portions being in contact with each resonant spring, are reduced, and thus reliability of a compressor can be improved. 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 modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents. WO 2005/033509 PCT/KR2003/002054 15 CLAIMS 1. A reciprocating compressor comprising: a driving unit having an outer stator and an inner stator disposed at a predetermined air gap therebetween, and a moving member positioned between the outer stator and the inner stator and linearly and reciprocally moved; a compression unit having a cylinder fixed at an inner circumferential surface of the inner stator, and a piston connected to the moving member and linearly moved in the cylinder; a support unit supporting the compression unit and the driving unit; and a resonant spring unit positioned at a rear portion of the driving unit, installed at the support unit and inducing a resonant movement of the piston. 2. The compressor of claim 1, wherein the cylinder is fixed at the inner circumferential surface of the inner stator by a press-fit method or the like. 3. The compressor of claim 1, wherein the support unit comprises: a first frame supporting an outer circumferential surface of the cylinder, one side surface of the outer stator, and one side surface of the inner stator; a second frame supporting the other side surface of the outer stator; and a third frame coupled with the second frame and receiving the resonant WO 2005/033509 PCT/KR2003/002054 16 spring unit. 4. The compressor of claim 3, wherein, in the first frame, an outer circumferential surface of the cylinder is fixed at the inner circumferential surface of the first frame by a press-fit method or the like, one side surface of the inner stator is supported at its inner side surface, and one side surface of the outer stator is supported at its outer side surface. 5. The compressor of claim 3, wherein the resonant spring unit comprising: a spring support member mounted to a portion where the piston and the moving member are connected; plural first resonant springs disposed between the second frame and one side surface of the spring support member; and plural second resonant springs disposed between the third frame and the other side surface of the spring support member. 6. The compressor of claim 5, wherein the first resonant springs are arranged at a predetermined interval in a circumferential direction, and the second resonant springs are arranged between the first resonant springs respectively. 7. The compressor of claim 5, wherein the first resonant springs and the second resonant springs are disposed so as to overlap at a WO 2005/033509 PC17KR2003/002054 17 predetermined section in an axial direction of the compressor 8. The compressor of claim 5, wherein the first and second springs are disposed to be parallel in the axial direction of the compressor. 9. The compressor of claim 5, wherein the first and the second resonant springs are formed of compression coil springs, and the first and the second resonant springs is mounted at spring support member so that an end portion of spring, a center of spring and a center of piston are arranged in line. 10. The compressor of claim 5, wherein the spring support member comprising: a coupling portion coupled with a portion where the moving member and the piston are connected, and positioned at a rear portion of the piston; a first support portion prolonged from the edge of the coupling portion at a predetermined interval in a circumferential direction and supporting the first resonant spring; and a second support portion positioned between the first support portions and supporting the second resonant spring. 11. The compressor of claim 10, wherein the disc-shaped coupling portion has a passage through which a fluid passes, at its center portion, and fixed at portion where the piston and the moving member are connected. WO 2005/033509 PC17KR2003/002054 18 12. The compressor of claim 10, wherein the first support portion is bent, rearwardly prolonged from the edge of the coupling portion, and formed so that its end portion is bent toward outside of the coupling portion to support the first resonant springs. 13. The compressor of claim 10, wherein the second support portion is radially prolonged from the edge of the coupling portion at a predetermined interval. 14. The compressor of claim 10, wherein the first support portion and the second support portion are alternatively formed in a circumferential direction of the coupling portion. 15. The compressor of claim 10, wherein spring sheet portions for fixing the first and the second resonant springs are formed at the first and the second support portions respectively. 16. The compressor of claim 15, wherein the spring seat portions respectively are formed as a cylindrical shape which is extended from respective sides of the first and second supporting portions, and the spring seat portions respectively have a hole formed therein. A reciprocating compressor includes a driving unit (16) having an outer stator (26) and an inner stator disposed at a predetermined air gap there between, and a moving member positioned between the outer stator (26) and the inner stator (28) and linearly and reciprocally moved; a compression unit (18) having a cylinder (38) fixed at an inner circumferential surface of the inner stator (28) and a piston (22) linearly moved in the cylinder (38) by being connected to the moving member; a support portion (20) supporting the compression unit (18) and the driving unit (16); and a resonant spring unit positioned (24) at a rear portion of the driving unit (16), disposed at the support portion (20), and inducing a resonant movement of the piston (22). Therefore, a resonant spring (62,64) of the compressor can be moved horizontally and straight forwardly by reducing a torsion moment of the resonant spring (62,64), a width of the compressor can be reduced, and a concentricity of a driving unit (16) and a compression unit can be maintained.

Full Text

The present invention relates to a reciprocating compressor, and
particularly to a reciprocating compressor that can be compact in size and
having improved performance.
BACKGROUND ART
Figure 1 is a sectional view showing a reciprocating compressor in
accordance with one example of a conventional art.
A conventional reciprocating compressor includes a close casing to
which a suction pipe 102 and a discharge pipe 104 are connected
respectively; a driving unit 108 disposed in the casing 106 and generating a
reciprocal movement force; a compression unit 110 transmitted the reciprocal
movement force generated at the driving unit 108 and compressing a fluid; a
support portion 112 supporting the driving unit 108 and the compression unit
110.
The driving unit 108 includes an outer stator 116 fixed at the support
portion 112 and having a winding coil 114 to which power is applied; an inner
stator 118 disposed at an inner circumferential surface of the outer stator 116
with a predetermined air gap therebetween; a magnet 120 positioned at the air
gap between the outer stator 116 and the inter stator 118 and linearly and
reciprocally moved when power is applied to the winding coil 114; and a
moving member 122 mounted to the magnet 120 at a same interval in a

WO 2005/033509 PCT/KR2003/002054
2
circumferential direction and transmitting a linear movement of the magnet
120 to the piston 124 by being coupled with a piston 124 of. the compression,
unit 110.
The compression unit 110 includes a piston 124 linearly and
reciprocally moved by being coupled with the moving member 122; a cylinder
130, in which the piston 124 is slidably inserted, having a compression
chamber; and a suction valve 132 installed at a front portion of the piston 124
to prevent the fluid introduced into the compression chamber from being
flowed backwardly; a discharge valve assembly 134 installed at a front portion
of the cylinder 130 to perform an open-and-shut action of a discharged fluid.
The support unit 112 includes a first frame 140 to which the inner stator
118 is fixed, mounted to an outer circumferential surface of the cylinder 130,
and supporting one side surface of the outer stator 116; a second frame 142
supporting the other side surface of the outer stator 116; a third fame 144
coupled with the second frame 142 and receiving a resonant spring unit 146,
The resonant spring unit 146 for inducing a resonant movement of the
piston 124, includes a first resonant spring 148 interposed between the first
frame and one side surface of a connecting portion 152 between the moving
member 122 and the piston 124, and providing an elastic force to the piston
124 when the piston 124 is rearwardly moved; and second resonant spring
150 interposed between the other side surface of the connecting portion 152
and the third frame 144, and providing an elastic force to the piston 124 when
the piston 124 is forwardly moved in order to compress a fluid.
Herein, the first resonant spring 148 and the second resonant spring

WO 2005/033509 PCT/KR2003/002054
3
150 are formed of a compression coil spring. The first resonant spring 148 has
a bigger diameter than an outer diameter of the cylinder 130 and positioned at
the outer circumferential surface of the cylinder 130, and the second resonant
spring 150 is positioned at a rear portion of the compression unit 110.
In the convention reciprocating compressor, when power is applied to a
winding coil 114, a flux is formed between the outer stator 115 and the inner
stator, and thus the magnet 120 and the moving member 122 are linearly and
reciprocally moved. While the piston 124 connected to the moving member
122 is linearly and reciprocally moved in the cylinder 130, a fluid is
compressed.
At this time, when the piston 124 forwardly moves to compress a fluid,
an elastic force of a second resonant spring 150 is provided to the piston 124,
and when moving rearwardly, an elastic force of a first resonant spring 148 is
provided to the piston 124.
However, in the conventional reciprocating compressor, the first
resonant spring 148 is positioned in a space between an outer circumferential
surface of the cylinder 130 and an inner circumferential surface of the inner
stator 118. Accordingly, a width of a compressor should be big because a
predetermined space should be secured to install the first resonant spring 148
between the outer circumferential surface of the cylinder 130 and the inner
stator 118.
Also, since the first and the second springs 148 and 150 are formed of
a compression coil spring having a torsion moment, and are disposed at the
both sides of a connection unit 152 between the moving member 122 and the

WO 2005/033509 PCT7KR2003/002054
4
piston respectively, the torsion moment occurs while the first and the second
springs 148 and 150 repeatedly compress and expand. Because of this, it is
difficult for the piston 124 to keep its linear movement, so performance of a
motor is deteriorated.
Figure 2 is a sectional view showing a reciprocating compressor for
solving those problems according to another example of the conventional art.
In a reciprocating compressor shown in Figure 2, a compression unit
110 is disposed at a front portion of a casing 106 and fixed at a first frame 162,
and a driving unit 108 is disposed at a rear portion of the casing 106, and fixed
at second and third frames 164 and 166. A moving member 122 of the driving
unit 108 and a piston 124 are connected mechanically and a spring supporting
member is disposed at a connection portion of the moving member 122 and
the piston 124.
Also, plural first resonant springs 172 are disposed between the first
frame 162 and a front portion surface of the spring supporting member 176 at
a predetermined interval in a circumferential direction. Plural second resonant
springs 174 are disposed between a rear portion surface of the spring
supporting member 176 and the second frame at a predetermined interval in a
circumferential direction.
In the reciprocating compressor, a width of the compressor 110 can be
reduced since the driving unit 108 and the compression unit 110 are
positioned at front and rear portions of the casing 106 respectively and the
first resonant spring 172 and the second resonant spring 174 are disposed at
an outer circumferential portion of the compression 110. Also, since; the plural

WO 2005/033509 PCT/KR2003/002054
5
first and second resonant springs 172 and 174 are disposed in a
circumferential direction, a torsion moment caused by repeated compression
and expansion of the springs can be reduced.
However, in the reciprocating compressor according to the
conventional art, the driving unit 108 generating a reciprocal movement force
and the compression unit 110 transmitted the movement force from the driving
unit 108 are disposed at the front portion and at rear portions of the
compressor at a predetermined interval. Accordingly, it is difficult to adjust a
concentricity of the driving unit 109 and the compression unit 110, and thus
degrading of assembling is caused.
That is, even though a concentricity of the inner and outer stators 116
and 118 of the driving unit 108 has been adjusted, a concentricity of the
driving unit 108 and the piston 124 of the compression unit 110 has to be
adjusted again, and thus a difficulty of assembling is caused.
In addition, since the driving unit 108 and the compression unit 110 are
disposed at the front and rear portions of the casing 106 respectively, the
concentricity of the piston 124 is severely deviated even though the
concentricity of the moving member 122 is little bit deviated during an
operation of the compressor. This causes a collision of the cylinder 130 and
the piston 124 and, accordingly, performance of the compressor is
deteriorated.
DISCLOSURE OF THE INVENTION
Therefore, it is an object of the present invention to provide a

WO 2005/033509 PCT/KR2003/002054
6
reciprocating compressor capable of moving a resonant spring horizontally
and straight forwardly by reducing a torsion moment of the resonant spring,
reducing a width of the compressor, and maintaining a concentricity of a
driving unit and a compression unit.
To achieve the above objects, there is provided a reciprocating
compressor including a driving unit having an outer stator and an inner stator
disposed at a predetermined air gap therebetween, and a moving member
positioned between the outer stator and the inner stator and linearly and
reciprocally moved; a cylinder fixed at an inner circumferential surface of the
inner stator; a compression unit coupled with the moving member and linearly
and reciprocally moved in the cylinder; a support unit for supporting the
compression unit and the driving unit; a resonant spring unit disposed at a
rear portion of the driving unit, disposed at the support portion and inducing a
resonant movement of the piston..
The cylinder is fixed at the inner circumferential surface of the inner
stator by a press-fit method.
The support unit includes a first frame supporting an outer
circumferential surface of the cylinder and one side surface of each of outer
stator and inner stator; a second frame supporting the other side surface of
the outer stator; a third frame coupled with the second frame and receiving the
resonant spring unit.
The resonant spring unit includes a spring support member mounted to
a portion where the piston and moving member are connected; plural first
resonant springs disposed between the second frame and one side surface of

WO 2005/033509 PC17KR2003/002054
7
the spring support member; plural second resonant springs disposed between
the third frame and the other side surface of the spring support member.
The spring support member includes a coupling portion coupled with a
portion where the moving member and the piston are connected, and
disposed at a rear portion of the piston; a first support portion where the first
resonant spring is supported, prolonged from an edge of the coupling portion
at a predetermined interval in a circumferential direction; a second support
portion where the second resonant spring is supported, disposed between the
first support portions
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a sectional view showing a reciprocating compressor in
accordance with one example of the conventional art.
Figure 2 is a sectional view showing a reciprocating compressor in
accordance with another example of the conventional art.
Figure 3 is a sectional view showing a reciprocating compressor in
accordance with one embodiment of the present invention.
Figure 4 is a sectional view showing a state that an inner stator of a
reciprocating compressor and a cylinder are coupled in accordance with the
present invention.
Figure 5 is a sectional view taken along line V-V of Figure 4.
Figure 6 is a perspective view showing a resonant spring unit of a
reciprocating compressor in accordance with the present invention.
Figure 7 is a side view showing a disposition state of resonant springs

WO 2005/033509 PC17KR2003/002054
8
of a reciprocating compressor in accordance with the present invention.
Figures 8 and 9 are partial sectional views showing a fixing state of a
resonant spring in accordance with the present invention.
Figures 10 and 11 are front views showing a winding direction of a
resonant spring of a reciprocating compressor in accordance with the present
invention.
MODES FOR CARRYING OUT THE PREFERRED EMBODlMiENTS
A first embodiment of the present invention will now be described with
reference to the accompanying drawings.
There can be a plurality of embodiments of the reciprocating
compressor in accordance with the present invention, and a preferred
embodiment will now be described.
Figure 3 is a sectional view of a reciprocating compressor according to
the present invention.
The reciprocating compressor of the present invention includes a
casing 14 to which a suction pipe 10 and a discharge pipe12 are connected
respectively; a driving unit 16 disposed in the casing 14 and generating a
reciprocal movement force; a compression unit 18 disposed in the driving unit
16 and compressing a fluid by being transmitted the reciprocal movement
force of the driving unit 16; a support unit 20 supporting the driving unit 16 and
the compression unit 18; a resonant spring assembly 24 installed at the
support unit 20 and inducing a resonant movement of the piston 22 by
providing an elastic force to the piston 22 of the compression unit 18.

WO 2005/033509 PCT/KR2003/002054
9
The driving unit 16 includes an outer stator 26 fixed at the support
portion 20; an inner stator 28 disposed between itself and an inner
circumferential surface of the outer stator 26 at a predetermined air gap; a
winding coil 30 to which power is applied, disposed at one of the outer stator
28 and the inner stator 28; a magnet 32 installed at the air gap between the
outer stator 26 and the inner stator 28, and linearly and reciprocally moved
when power is applied to the winding coil 30; a moving member 34 at which
the magnet 32 is fixed at a same interval in a circumferential direction,
transmitting a linear movement of the magnet to the piston 22 by being
coupled with the piston 22 of the compression unit 18.
The compression unit 18 includes a cylinder 38 fixed at the inner
circumferential surface of the inner stator 28, and having a compression
chamber 36 in which a fluid is compressed; a piston 22 linearly and movably
inserted in the cylinder 38, coupled with the moving member 34, linearly
moved when the moving member 32 is linearly moved, thereby compressing a
fluid in the compression chamber 36; a suction valve 40 mounted to a front
portion of the piston 122 to prevent the fluid introduced into the compression
chamber from being flowed backwardly; a discharge valve assembly 42
disposed.at a front portion of the cylinder 38 to perform an open-and-shut
action of a discharged fluid.
Herein, as shown in Figures 4 and 5, the cylinder 38 is fixed at the inner
circumferential surface of the inner stator 28 by a press-fit method or the like.
That is, since the cylinder is directly fixed at the inner circumferential surface
of the inner stator 28 and thus there is no gap therebetween, a width of the

WO 2005/033509 PCT/KR2003/002054
10
compressor can be reduced.
The support unit 20 includes a first frame 46 mounted to the outer
circumferential surface of the cylinder 38, and supporting one side surface of
the outer stator 26; a second frame 48 supporting the other side surface of the
outer stator 26; a third frame 50 coupled with the second frame 48 and
receiving a resonant spring unit 24.
In the first frame 46, an outer circumferential surface of the cylinder 38
is supported at the inner circumferential surface of the first frame 46 by the
press-fit method or the like, one side surface of the inner stator 28 is
supported at its inner side surface, and one side surface of the outer stator 26
is supported at its outer side surface.
In the second frame 48, the other side surface of the outer stator 26 is
supported at one side surface of the second frame 48. At the outer side
surface of the second frame 48, the third frame 50 is fixed, and springs of the
resonant spring unit 24 are supported.
In the cylindrical-shaped third frame 50, its one end is fixed at the
second frame 48, and prolonged at a certain length toward the rear portion of
the casing 14. A fluid passage 52 through which a fluid taken into the inlet 10
passes, is formed at the other end of the third frame 50, and springs of the
resonant spring unit 24 are supported at its inner surface.
As shown in Figure 6, the resonant spring unit 24 includes a spring
support member 60 mounted to a portion where the piston 22 and the moving
member 34 are connected; a first resonant spring 62 disposed between the
second frame 48 and one side surface of the spring support member 60, and

WO 2005/033509 PCT/KR2003/002054
11
providing an elastic force to the piston 22 when the piston moves rearwardly;
a second resonant spring 64 disposed between the inner surface of the third
frame 50 and the other side surface of the spring support member 60 and
providing an elastic force to the piston 22 when the piston moves forwardly.
Herein, the spring support member 60 includes a coupling portion 66
positioned at the rear portion of the piston 22 and fixed at a portion where the
moving member 34 and the piston 22 are coupled; plural first support portions
68 prolonged from the edge of the coupling portion 66 at a certain interval in a
circumferential direction and supporting the first resonant springs 62; second
support portions 70 positioned between the first support portions 68, and
supporting the second resonant spring 64.
The disc-shaped coupling portion 66 has a passage 75 through which a
fluid passes, at its center portion. The first support portion 68 is rearwardly
prolonged from the edge of the coupling portion 66 at a certain length, and is
outwardly bent at its end portion so as to install the first resonant springs 62.
Plural first support portions 68 are formed at a certain interval in a
circumferential direction of the coupling portion 66.
The second support portions 70 are disposed between the first support
portions 68 respectively, are radially prolonged from the edge of the coupling
portion 66, and thus support the second resonant springs 64.
In the first resonant spring 62, its both end portions are supported at
the second frame 48 and at the first support portion 68 of the spring support
member 60 respectively. In the second resonant spring 64, its both end
portions are supported at the third frame 50 and at the second support portion

WO 2005/033509 PCT/KR2003/002054
12
70 of the spring support member 60 respectively. Because of these, as shown
in Figure 7, when the compressor is viewed from the side, the first resonant
spring 62 and the second resonant spring 64 have an overlap section (L).
Since the first resonant spring 62 and the second resonant spring 64 have the
overlap section (L) in an axial direction of the compressor, a length in the axial
direction of the compressor can be reduced.
In a different example of the spring support member 60, an overlap
section of the first resonant spring 62 and the second resonant spring 64 can
be extended more by forming the second support portion to be bent.
As shown in Figure 8, spring sheet portions 80 for supporting the first
and the second resonant springs are formed at side surfaces of the first and
the second support portions 68 and 70 respectively. The cylinder-shaped
spring sheet portions 80 are prolonged from the side surfaces of the first and
the second support portions 68 and 70 and support the first and the second
resonant springs 62 and 64 respectively.
Figure 9 shows a special spring sheet member 82 mounted to each of
the first and the second support portions 68 and 70 to support the first and the
second resonant springs 62 and 64. The spring sheet member 82 consists of
a fixing portion 84 inserted and fixed at a through hole 88 formed in each one
of the first and the second resonant springs 62 and 64 by a press fit method or
the like; and a sheet portion 86 prolonged from the fixing portion 84 and
supporting the first and the second resonant springs 62 and 64.
The first and the second resonant springs 62 and 64 are formed of
compression coil springs respectively, and offsetting torsion moments of each

WO 2005/033509 PCT/KR2003/002054
13
other by having an opposite winding direction. As shown in Figure 10, that is,
as shown in Figure 10, if the first resonant spring supported at the first support
portion 68 is wound counterclockwise as the arrow P, the second resonant
spring 64 disposed neighboring on the first resonant spring 62 is wound
clockwise as the arrow Q.
As shown in Figure 11, the winding directions of the first resonant
springs 62 disposed to face each other are different with each other, and the
winding directions of the second resonant springs 64 disposed to face each
other are different with each other, too. That is, if one first resonant: spring 62
is wound in a direction of the arrow S, the other neighboring first resonant
spring 62 is wound in a direction of the arrow T. Also, if one second resonant
spring 64 is wound in a direction of the arrow T, the other neighboring second
resonant spring 64 is wound in a direction of the arrow S.
Operations and effects of the reciprocating compressor will now be
described.
When power is applied to a winding coil 30, a flux is formed between an
outer stator 26 and an inner stator 28. By the flux, a moving member 34 is
linearly and reciprocally moved, and thus a piston 22 connected to the moving
member 34 compresses and discharge a fluid introduced into a compression
chamber while being moved linearly and reciprocally in a cylinder 34,
At this time, when the piston 22 moves forwardly to compress a fluid,
an elastic force of a second resonant spring 62 is provided to the piston 22,
and when the piston 22 moves rearwardly, an elastic force of a first resonant
spring 64 is provided to the piston 22,

WO 2005/033509 PCT7KR2003/002054
14
In the reciprocating compressor in accordance with the present
invention, a width of the compressor can be reduced since a piston is directly
fixed at the inner circumferential surface of the inner stator by a press-fit
method or the like.
An interval in a longitudinal direction between a moving member and a
piston can be minimized by positioning the piston in a moving member,
whereby a concentricity of the moving member and the piston can be easily
adjusted during assembling, and an attrition of the piston and the cylinder and
a collision of the moving member and the outer/inner stators are prevented.
A length in an axial direction of the compressor can be reduced by
disposing first and second resonant springs so as to overlap at a certain
section.
And, the plural first and second resonant springs are disposed in a
circumferential direction, and their winding directions are arranged to be
opposite with each other. Accordingly, since a torsion moment, which may
occurs while each resonant spring compresses and expands, is prevented, a
torsion of the piston and an attrition of portions being in contact with each
resonant spring, are reduced, and thus reliability of a compressor can be
improved.
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 modifications and variations of this invention provided they
come within the scope of the appended claims and their equivalents.

WO 2005/033509 PCT/KR2003/002054
15
CLAIMS
1. A reciprocating compressor comprising:
a driving unit having an outer stator and an inner stator disposed at a
predetermined air gap therebetween, and a moving member positioned
between the outer stator and the inner stator and linearly and reciprocally
moved;
a compression unit having a cylinder fixed at an inner circumferential
surface of the inner stator, and a piston connected to the moving member and
linearly moved in the cylinder;
a support unit supporting the compression unit and the driving unit; and
a resonant spring unit positioned at a rear portion of the driving unit,
installed at the support unit and inducing a resonant movement of the piston.
2. The compressor of claim 1, wherein the cylinder is fixed at the
inner circumferential surface of the inner stator by a press-fit method or the
like.
3. The compressor of claim 1, wherein the support unit comprises:
a first frame supporting an outer circumferential surface of the cylinder,
one side surface of the outer stator, and one side surface of the inner stator;
a second frame supporting the other side surface of the outer stator;
and
a third frame coupled with the second frame and receiving the resonant

WO 2005/033509 PCT/KR2003/002054
16
spring unit.
4. The compressor of claim 3, wherein, in the first frame, an outer
circumferential surface of the cylinder is fixed at the inner circumferential
surface of the first frame by a press-fit method or the like, one side surface of
the inner stator is supported at its inner side surface, and one side surface of
the outer stator is supported at its outer side surface.
5. The compressor of claim 3, wherein the resonant spring unit
comprising:
a spring support member mounted to a portion where the piston and
the moving member are connected;
plural first resonant springs disposed between the second frame and
one side surface of the spring support member; and
plural second resonant springs disposed between the third frame and
the other side surface of the spring support member.
6. The compressor of claim 5, wherein the first resonant springs
are arranged at a predetermined interval in a circumferential direction, and the
second resonant springs are arranged between the first resonant springs
respectively.
7. The compressor of claim 5, wherein the first resonant springs
and the second resonant springs are disposed so as to overlap at a

WO 2005/033509 PC17KR2003/002054
17
predetermined section in an axial direction of the compressor
8. The compressor of claim 5, wherein the first and second springs
are disposed to be parallel in the axial direction of the compressor.
9. The compressor of claim 5, wherein the first and the second
resonant springs are formed of compression coil springs, and the first and the
second resonant springs is mounted at spring support member so that an end
portion of spring, a center of spring and a center of piston are arranged in line.
10. The compressor of claim 5, wherein the spring support member
comprising:
a coupling portion coupled with a portion where the moving member
and the piston are connected, and positioned at a rear portion of the piston;
a first support portion prolonged from the edge of the coupling portion
at a predetermined interval in a circumferential direction and supporting the
first resonant spring; and
a second support portion positioned between the first support portions
and supporting the second resonant spring.
11. The compressor of claim 10, wherein the disc-shaped coupling
portion has a passage through which a fluid passes, at its center portion, and
fixed at portion where the piston and the moving member are connected.

WO 2005/033509 PC17KR2003/002054
18
12. The compressor of claim 10, wherein the first support portion is
bent, rearwardly prolonged from the edge of the coupling portion, and formed
so that its end portion is bent toward outside of the coupling portion to support
the first resonant springs.
13. The compressor of claim 10, wherein the second support portion
is radially prolonged from the edge of the coupling portion at a predetermined
interval.
14. The compressor of claim 10, wherein the first support portion
and the second support portion are alternatively formed in a circumferential
direction of the coupling portion.

15. The compressor of claim 10, wherein spring sheet portions for
fixing the first and the second resonant springs are formed at the first and the
second support portions respectively.
16. The compressor of claim 15, wherein the spring seat portions
respectively are formed as a cylindrical shape which is extended from
respective sides of the first and second supporting portions, and the spring
seat portions respectively have a hole formed therein.
A reciprocating compressor includes a driving unit (16) having an outer stator (26) and an inner stator disposed at a predetermined air gap there between, and a moving member positioned between the outer stator (26) and the inner stator (28) and linearly and reciprocally moved; a compression unit (18) having a cylinder (38) fixed at an inner circumferential surface of the inner stator (28) and a piston (22) linearly moved in the cylinder (38) by being connected to the moving member; a support portion (20) supporting the compression unit (18) and the driving unit (16); and a resonant spring unit positioned (24) at a rear portion of the driving unit (16), disposed at the support portion (20), and inducing a resonant movement of the piston (22). Therefore, a resonant spring (62,64) of the compressor can be moved horizontally and straight forwardly by reducing a torsion moment of the resonant spring (62,64), a width of the compressor can be reduced, and a concentricity of a driving unit (16) and a compression unit can be maintained.

Documents:

« Previous Patent

Next Patent »

Patent Number

218993

Indian Patent Application Number

01877/KOLNP/2005

PG Journal Number

16/2008

Publication Date

18-Apr-2008

Grant Date

16-Apr-2008

Date of Filing

20-Sep-2005

Name of Patentee

LG ELECTRONICS INC.

Applicant Address

20, YOIDO-DONG, YOUNGDUNGPO-GU, SEOUL 150-010 REPUBLIC OF KOREA

Inventors:

#	Inventor's Name	Inventor's Address
1	HYEON, SEONG-YEOL	JUGONG APT. 209-302, SHIWUL-DONG, CHANG-WON, GYUNGSANGNAM-DO 641-060, REPUBLIC OF KOREA

PCT International Classification Number

F04B 35/04

PCT International Application Number

PCT/KR2003/002054

PCT International Filing date

2003-10-06

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA