KR20090012860A - Two stage rotary compressor - Google Patents

Abstract

A 2-stage rotary compressor is provided to improve performance and reduce input power while reducing the wear of parts by reducing friction loss between a low pressure eccentric part and a low pressure roller. Friction reducing grooves(122a) are formed between a rotation shaft(113) and a roller(123) engaged with the rotation shaft for reducing a friction area between the rotation shaft and the roller. The rotation shaft has at least two or more eccentric parts(122,132) in different direction and the friction reducing grooves are formed in outer peripheral surfaces of the eccentric parts.

Description

Rotary two stage compressor {TWO STAGE ROTARY COMPRESSOR}

1 is a view showing an example of a conventional rotary twin compressor.

2 is a view showing an example of a conventional rotary two-stage compressor.

Figure 3 is a schematic diagram showing an example of a cycle comprising a rotary two-stage compressor according to the present invention.

4 is a view showing an example of a rotary two-stage compressor according to the present invention.

5 is a view showing an example of a low pressure compression assembly of a rotary two-stage compressor according to the present invention.

6 and 7 are a view of a portion of the rotary two stage compressor according to the present invention from above and below.

8 is a view showing a part of the rotary two-stage compressor according to the present invention cut away.

9 is a view showing an example of a rotary shaft of a rotary two-stage compressor according to the present invention.

10 is a view showing an example of the installation structure of the rollers on the rotary shaft of the rotary two-stage compressor according to the present invention.

11 to 13 is a graph showing the input power according to the friction reducing groove size, which is the main part of the present invention.

<Explanation of symbols on main parts of the drawings>

100: rotary compressor 110: electric motor

113: shaft 120: low pressure compression assembly

130: high pressure compression assembly 140: intermediate plate

151: inlet pipe 152: outlet pipe

153: injection pipe 180: internal flow path

The present invention relates to a rotary compressor in which a roller that is integrally rotated with a rotating shaft compresses a refrigerant while rolling along the inside of a cylinder, and in particular, a rotary type that can reduce friction loss and component wear by reducing friction between the rotating shaft and the roller. However, it relates to a compressor.

In general, a compressor is a mechanical device that increases pressure by receiving power from a power generator such as an electric motor or a turbine to compress air, refrigerant, or various other working gases. It is widely used throughout.

These compressors can be classified into reciprocating compressors for compressing refrigerant while linearly reciprocating inside the cylinders by forming a compression space in which the working gas is absorbed and discharged between the piston and the cylinder. Rotary compressor that compresses the refrigerant while the roller is eccentrically rotated along the inner wall of the cylinder so that a compression space for absorbing and discharging the working gas is formed between the roller and the eccentric rotating roller and the cylinder. And a scroll compressor for compressing the refrigerant while the turning scroll is rotated along the fixed scroll to form a compressed space in which the working gas is sucked and discharged between the orbiting scroll and the fixed scroll. Divided into

Particularly, the rotary compressor includes two rollers and two cylinders at the upper and lower portions, and a rotary twin compressor at the upper and lower rollers and the cylinder pair compresses part of the total compression capacity and the other and the upper and lower portions. Rotary two-stage with two rollers and two cylinders, two cylinders in communication, one pair compresses relatively low pressure refrigerant, and the other pair compresses relatively high pressure refrigerant after low pressure compression More advanced, such as a compressor.

In the Republic of Korea Patent Publication No. 1994-001001 a rotary compressor is disclosed. The motor is located inside the shell, and a rotating shaft is installed to penetrate the motor. In addition, a cylinder is located under the electric motor, and an eccentric portion fitted to the rotating shaft and a roller fitted to the eccentric portion are located inside the cylinder. The cylinder has a coolant discharge hole and a coolant inlet hole, and a vane is provided between the coolant discharge hole and the coolant inlet hole to prevent the uncompressed low pressure refrigerant from mixing with the compressed high pressure refrigerant. In addition, a spring is installed at one end of the vane to maintain the eccentric and rotating roller and the vane in contact. When the rotating shaft is rotated by the motor, the eccentric portion and the roller rotate along the inner circumference of the cylinder to compress the refrigerant gas, and the compressed refrigerant gas is discharged through the refrigerant discharge hole.

Republic of Korea Patent Publication No. 10-2005-0062995 discloses a rotary twin compressor. Referring to FIG. 1, two cylinders 1035 and 1045 and an intermediate plate 1030 which compress the same capacity are provided, and the compression capacity is improved by twice compared to the first stage compressor.

Republic of Korea Patent Publication No. 10-2007-0009958 discloses a rotary two-stage compressor. Referring to FIG. 2, the compressor 2001 includes an electric motor 2014 having a stator 2007 and a rotor 2008 above an inside of a sealed container 2013, and a rotating shaft 2002 connected to the electric motor 2014. Has two eccentrics. The main bearing 2009, the high pressure compression element 2020b, the intermediate plate 2015, the low pressure compression element 2020a and the sub bearing 2019 are laminated in order from the electric motor 2014 side with respect to the rotating shaft 2002. . Also disclosed is an intermediate tube 2040 for introducing refrigerant compressed in the low pressure compression element 2020a into the high pressure compression element 2020b.

However, in the conventional rotary two-stage compressor, the eccentric portion of the rotary shaft in the high pressure compression element in the high pressure compression element in order to form a compression space of the low pressure compression element larger than the compression space of the high pressure compression element due to the pressure difference. Since the contact area of the rotary shaft in the low pressure compression element becomes wider than the eccentric part of the axial part, the frictional loss is relatively large in the low pressure compression element, and as a result, a large input power is required. have.

The present invention has been made to solve the above problems of the prior art, it is an object of the present invention to provide a rotary two-stage compressor that can reduce the friction loss by reducing the eccentric contact area of the rotating shaft.

The present invention for solving the above problems is a sealed container; A rotating shaft which is provided in the sealed container and supplies oil while transmitting rotational force; At least two compression assemblies including a roller engaged with the rotation shaft and a cylinder for compressing the refrigerant while the roller rolls inwardly by the rotation of the rotation shaft; And, to reduce the friction area between the rotating shaft and the roller provides a rotary two-stage compressor comprising a; a friction reducing groove formed between the rotating shaft and the roller.

In addition, the rotating shaft includes at least two or more eccentric parts eccentric to the rotating shaft in a different direction so that the roller is engaged with the outer peripheral surface, the friction reducing groove provides a rotary two-stage compressor, characterized in that formed on the outer peripheral surface of the eccentric portion.

In addition, the friction reducing groove provides a rotary two-stage compressor, characterized in that formed in a strip shape along the circumferential direction in the center of the outer peripheral surface of the eccentric portion.

In addition, the compression assembly includes a low pressure compression assembly for compressing a low pressure refrigerant to a medium pressure while the low pressure roller engaged with the rotating shaft rolls inside the low pressure cylinder; It provides a rotary two-stage compressor comprising a; high pressure roller engaged with the rotating shaft to compress the medium pressure refrigerant to a high pressure while rolling the inside of the high pressure cylinder.

In addition, the rotary shaft includes a low pressure eccentric portion eccentrically in one direction on the rotary shaft so that the low pressure roller is engaged with the outer circumferential surface, and a high pressure eccentric portion eccentrically in a different direction from the low pressure eccentric portion on the rotary shaft so that the high pressure roller is engaged with the outer circumferential surface. It provides a rotary two-stage compressor, characterized in that formed on the outer peripheral surface of the low pressure eccentric portion.

In addition, the low pressure eccentric portion provides a rotary two-stage compressor, characterized in that the axial length is formed longer than the high pressure eccentric portion.

In addition, the friction reducing groove provides a rotary two-stage compressor, characterized in that formed in a strip shape along the circumferential direction in the center of the outer peripheral surface of the low-pressure eccentric portion.

In addition, the axial length of the low pressure eccentric portion with respect to the axial length of the low pressure roller provides a rotary two-stage compressor, characterized in that set within the range of 0.56 ~ 0.62.

In addition, the axial length of the groove for reducing friction with respect to the axial length of the low pressure eccentric portion provides a rotary two-stage compressor, characterized in that set within the range of 0.7 ~ 0.8.

In addition, the friction reducing groove provides a rotary two-stage compressor, characterized in that the depth is set within the range of 0.01 ~ 1mm in the radial direction from the outer diameter of the low pressure eccentric portion.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 is a schematic diagram showing an example of a cycle including a rotary two-stage compressor according to the present invention. The heating cycle includes components such as rotary two stage compressor 100, condenser 300, evaporator 400, phase separator 500, and four-way valve 600. Among them, the condenser 300 constitutes an indoor unit, and the compressor 100, the evaporator 400, and the phase separator 500 constitute an outdoor unit. The refrigerant compressed by the compressor 100 is introduced into the condenser 300 of the indoor unit through the four-way valve 600, and the compressed refrigerant gas is condensed by exchanging heat with the surroundings. The condensed refrigerant passes through the expansion valve to low pressure. The refrigerant passing through the expansion valve is separated into gas and liquid in the phase separator 500, and the liquid flows into the evaporator 400. The liquid is evaporated by heat exchange in the evaporator 400 and flows into the accumulator 200 in a gas state, and flows into the low pressure compression assembly (not shown) through the refrigerant inlet pipe 151 of the compressor 100 in the accumulator 200. do. In addition, the gas separated from the phase separator 500 is introduced into the compressor 100 through the injection pipe 153. The medium pressure refrigerant compressed by the low pressure compression assembly of the compressor 100 and the refrigerant introduced through the injection tube 153 are introduced into the high pressure compression assembly (not shown) of the compressor 100 and compressed to high pressure. The discharge pipe 152 is discharged to the outside of the compressor 100 again.

4 is a view showing an example of a rotary two-stage compressor according to the present invention. Rotary two-stage compressor 100 according to an embodiment of the present invention, the lower pressure compression assembly 120, the intermediate plate 140, the high pressure compression assembly 130 and the electric motor 110 from the bottom in the sealed container 101 It includes. In addition, it includes a refrigerant inlet pipe 151 penetrating through the sealed container 101 and connected to the accumulator 200 and a refrigerant discharge pipe 152 for discharging the compressed refrigerant to the outside of the sealed container.

The motor 110 includes a stator 111, a rotor 112, and a rotation shaft 113. The stator 111 includes a lamination of a ring-shaped electrical steel sheet and a coil wound on the lamination. The rotor 112 also has a lamination in which an electronic steel sheet is laminated. The rotating shaft 113 penetrates the center of the rotor 112 and is fixed to the rotor 112. When the electric current is applied to the electric motor 110, the rotor 112 is rotated by the mutual electromagnetic force between the stator 111 and the rotor 112, the rotary shaft 113 fixed to the rotor 112 also the rotor 112 Rotate with The rotating shaft 113 extends from the rotor 112 to the low pressure compression assembly 120 so as to penetrate the center portion of the low pressure compression assembly 120, the intermediate plate 140, and the high pressure compression assembly 130.

The low pressure compression assembly 120 and the high pressure compression assembly 130 are stacked in the order of the low pressure compression assembly 120-the middle plate 140-the high pressure compression assembly 130 from the bottom with the intermediate plate 140 interposed therebetween. Can be. Conversely, the high pressure compression assembly 120, the middle plate 140, and the high pressure compression assembly 130 may be stacked in the order from the bottom. In addition, regardless of the stacking order of the low pressure compression assembly 120, the middle plate 140 and the high pressure compression assembly 130, the lower bearing and the upper bearing 161 and the upper bearing 162 are respectively installed It helps the rotation of the rotary shaft 113, and supports the load of each component of the two-stage compression assembly stacked vertically. The upper bearing 162 is three-point welded to the hermetic container 101 to support the load of the two-stage compression assembly and fix it to the hermetic container 101.

The low pressure compression assembly 120 is connected to the refrigerant inlet pipe 151 introduced through the sealed container 101 from the outside. In addition, a lower bearing 161 and a lower cover 171 are positioned below the low pressure compression assembly 120, and an intermediate pressure chamber Pm is formed between the lower bearing 161 and the lower cover 171. The intermediate pressure chamber Pm is a space in which the refrigerant compressed in the low pressure compression assembly 120 is discharged, and is a space in which the refrigerant is temporarily stored before the refrigerant is introduced into the high pressure compression assembly 130, from the low pressure compression assembly 120. The high pressure compression assembly 130 serves as a buffer space on the flow path through which the refrigerant flows.

Looking at the structure in which the intermediate pressure chamber (Pm) is formed in the lower bearing 161, for example, the lower bearing 161 is protruded downward, the center portion in which the rotary shaft 131 is inserted / installed and the peripheral portion of the lower cover 171 abuts The lower cover 171 has a hole through which the rotating shaft 131 passes, and is formed in a flat shape in close contact with the lower bearing 161. In this case, the downwardly protruding peripheral portion of the lower bearing 161 and the flat peripheral portion of the lower cover 171 are bolted to the low pressure cylinder 121 at once. As another example, the lower bearing 161 may protrude downward only at the center of which the rotation shaft 113 is inserted / installed, and at the same time, other portions thereof may be formed flat, and the lower cover 171 may have a hole through which the rotation shaft 113 penetrates. The provided central portion may be formed flat, and at the same time, the periphery thereof may be stepped up to protrude upward. At this time, the flat peripheral portion of the lower bearing 161 and the peripheral portion protruding upwardly of the lower cover 171 are installed to be bolted to the low pressure cylinder 121 at once. In this case, the shape of the lower bearing 161 can be simplified to reduce the number of work, and the shape of the lower cover 171 can also be easily manufactured by pressing. Furthermore, the shape and the fastening method of the lower bearing 161 and the lower cover 171 are not limited to the above-mentioned method, and will be described an example in which the intermediate pressure chamber Pm is formed in the lower bearing 161. However, the intermediate pressure chamber Pm may be formed in any one of the upper bearing 162 and the intermediate plate 140.

A discharge port (not shown) is installed on an upper portion of the upper bearing 162 positioned above the high pressure compression assembly 130. The high pressure refrigerant discharged from the high pressure compression assembly 130 through the discharge port of the upper bearing 162 is discharged to the outside through the refrigerant discharge pipe 152 located above the sealed container 101.

The lower bearing 161, the low pressure compression assembly 120, the intermediate plate 140, and the high pressure compression assembly 130 have an internal flow path 180 connecting refrigerant from the low pressure compression assembly 120 to the high pressure compression assembly 130. ) Is formed. The inner flow passage 180 is formed vertically so as to be substantially parallel to the axial direction of the compressor.

Since the inner passage 180 is not a separate tube, the injection tube 153 (shown in FIG. 3) into which the refrigerant gas separated from the above-described phase separator 500 (shown in FIG. 3) flows into the inner passage 180. It can be installed anywhere. For example, a through hole (not shown) is formed in any one of the lower bearing 161, the intermediate plate 140, and the high pressure cylinder 131 forming the intermediate pressure chamber Pm, and the injection tube 153 is formed in the through hole. ), The refrigerant gas can be introduced, and the compression efficiency can be increased.

5 is a view showing an example of a low pressure compression assembly of a rotary two-stage compressor according to the present invention. The low pressure compression assembly 120 includes a low pressure cylinder 121, a low pressure eccentric 122, a low pressure roller 123, a low pressure vane 124, a low pressure elastic member 125, a low pressure inlet hole 126, and an intermediate pressure discharge hole. 127. The rotating shaft 113 passes through the center of the low pressure cylinder 121, and the low pressure eccentric portion 122 is fixed to the rotating shaft 113. In this case, the low pressure eccentric portion 122 may be integrally formed with the rotation shaft 113. In addition, the low pressure roller 123 is rotatably installed in the low pressure eccentric part 122, and the low pressure roller 123 rotates while rolling along the inner diameter of the low pressure cylinder 121 as the rotary shaft 113 rotates. The low pressure inlet hole 126 and the intermediate pressure discharge hole 127 are formed at both sides of the low pressure vane 124. In addition, the space in the low pressure cylinder 121 is divided by the low pressure vane 124 and the low pressure roller 123, and the refrigerant before and after compression coexists in the low pressure cylinder 121. It is partitioned by the low pressure vane 124 and the low pressure roller 123, and the portion including the low pressure refrigerant inlet hole 126 is the low pressure refrigerant inlet (S _l ), the middle portion containing the intermediate pressure discharge hole 127 in the middle It is called a pressurized refrigerant discharge part D _m . Here, the low pressure elastic member 125 is a means for applying a force to the low pressure vane 124 so that the low pressure vane 124 maintains contact with the low pressure roller 123. The vane hole 124h formed in the low pressure cylinder 121 is formed to penetrate the low pressure cylinder 121 laterally so that the low pressure vane 124 can be located. Through the vane hole 124, the low pressure vane 124 is guided, and the low pressure elastic member 125 that applies the force to the low pressure vane 124 extends through the low pressure cylinder 121 to the sealed container 101. . One end of the low pressure elastic member 125 is in contact with the low pressure vane 124, the other end is in contact with the closed container 101, so that the low pressure vane 124 maintains contact with the low pressure roller 123. To push.

In addition, the low pressure cylinder 121 has an intermediate pressure communication hole so that the refrigerant compressed in the low pressure compression assembly 120 may flow into the high pressure compression assembly 130 through the intermediate pressure chamber Pm formed by the lower bearing 161. 120a) is formed. The intermediate pressure communication hole 120a does not overlap with the refrigerant inlet pipe 151 inserted into the low pressure inlet hole 126, that is, the internal flow path 180 and the refrigerant inlet pipe 151 do not overlap with each other. ) Is formed. Although partially overlapped with the refrigerant inlet pipe 151, the medium pressure refrigerant is formed to flow into the high pressure compression assembly 130 from the intermediate pressure chamber Pm. However, in this case, since the internal flow path 180 can see the loss by the cross-sectional area overlapping the refrigerant inlet pipe 151, it is not preferable. In addition, as the refrigerant bypasses the vicinity of the refrigerant inlet pipe 151, the pressure may decrease.

As shown in FIG. 5, when the low pressure eccentric portion 122 rotates by the rotation of the rotary shaft 113, and the low pressure roller 123 rolls along the low pressure cylinder 121, the volume of the low pressure inflow portion S ₁ is reduced. Since the low pressure inlet S ₁ becomes low as it is increased, the refrigerant flows through the low pressure inlet hole 126. On the other hand, the intermediate pressure discharge portion (D _m), the volume is filled with the refrigerant in the intermediate pressure discharge portion (D _m) compression, it loses of, and is discharged through the intermediate pressure discharge holes (127). As the low pressure eccentric part 122 and the low pressure roller 123 rotate, the volume of the low pressure inlet part S ₁ and the intermediate pressure discharge part D _m continuously changes, and discharges the compressed refrigerant every one revolution.

6 to 8 is a view showing a part of a rotary two-stage compressor according to an embodiment of the present invention. In order from the bottom, the lower bearing 161, the low pressure compression assembly 120, the intermediate plate 140, and the high pressure compression assembly 130 are stacked. As described above, the low pressure refrigerant is introduced into the low pressure cylinder 121 through the refrigerant inlet pipe 151 and the low pressure inlet hole 126 and compressed, and then the low pressure compression assembly 120 through the intermediate pressure discharge hole 127. ) Is discharged into the intermediate pressure chamber (Pm), which is a space limited by the lower surface of the bottom and the lower bearing 161 and the lower cover 171. The intermediate pressure discharge hole 161h is formed in the lower bearing 161 so that the intermediate pressure discharge hole 127 and the intermediate pressure discharge hole 161h of the lower bearing 161 overlap each other. A valve (not shown) is installed below the intermediate pressure discharge hole 161h, and when the refrigerant compressed in the intermediate pressure discharge part Dm of the low pressure compression assembly 120 is compressed to a predetermined pressure, the refrigerant is discharged into the intermediate pressure chamber Pm. Be sure to The refrigerant discharged into the intermediate pressure chamber Pm is formed in the intermediate pressure communication hole 120a and the intermediate plate 140 formed in the low pressure cylinder 121 through the intermediate pressure communication hole 161a formed in the lower bearing 161. It passes through the intermediate pressure communication hole 140a and flows into the high pressure compression assembly 130 through the intermediate pressure inlet groove 130a of the high pressure cylinder 131. Intermediate pressure communication hole 161a of the lower bearing 161, intermediate pressure communication hole 120a of the low pressure compression assembly, intermediate pressure communication hole 140a of the intermediate plate 140, and intermediate pressure inflow of the high pressure compression assembly 130 The groove 130a forms an internal flow path 180 through which the medium pressure refrigerant compressed by the low pressure compression assembly 120 passes. At this time, the intermediate pressure inlet groove 130a of the high pressure compression assembly 130 is formed in the form of an inclined groove so as to communicate with the internal space of the high pressure cylinder 131. A lower portion of the intermediate pressure inlet groove 130a is formed to contact the intermediate pressure communication hole 140a of the intermediate plate 140 to form a part of the internal flow path 180, and the compressed medium pressure refrigerant is medium pressure inlet. It is introduced into the high pressure cylinder 131 through the groove 130a. When the medium pressure refrigerant flows into the high pressure compression assembly 130 through the internal flow path 180, the high pressure compression assembly 130 compresses the medium pressure refrigerant to the high pressure in the same operating principle as the low pressure compression assembly 120. do.

As described above, when the internal flow path 180 through which the medium pressure refrigerant passes is not formed by a separate pipe, but formed inside the sealed container 101, noise can be reduced, and the length of the internal flow path 180 is increased. Can be shortened, and the loss of the refrigerant pressure due to the resistance can be reduced. In addition, in the above described an example in which the intermediate pressure chamber (Pm) is formed in the lower bearing 161, the intermediate pressure chamber (Pm) may be formed in any one of the upper bearing 162 and the intermediate plate (140). . Accordingly, although the specific structure may vary slightly, in any case, the internal flow path 180 is formed inside the two-stage compression assembly, so that the medium pressure refrigerant compressed in the low pressure compression assembly 120 through the internal flow path 180 is formed. Guided to the high pressure compression assembly 130. Through this configuration, it is possible to shorten the length of the flow path through which the medium pressure refrigerant is guided, to minimize the flow loss, and to reduce noise and vibration without passing through the connection pipe passing through the hermetic container 101.

At this time, the intermediate pressure communication hole 120a of the low pressure compression assembly 120 constituting the internal flow path 180 to prevent the internal flow path 180 from being blocked by the refrigerant inlet pipe 151, and the intermediate pressure of the intermediate plate 140. The communication hole 140a and the intermediate pressure inlet groove 130a of the high pressure compression assembly 130 are formed to be spaced apart from the refrigerant inlet pipe 151 when viewed in the axial direction of the compressor 100.

The intermediate pressure communication hole 161a of the lower bearing 161 is formed to avoid the position where the refrigerant inlet pipe 151 is inserted so as not to overlap with the refrigerant inlet pipe 151 connected to the low pressure cylinder 121. The refrigerant inlet pipe 151 is inserted into the low pressure inlet hole 126 formed in the low pressure cylinder 121. The low pressure inlet hole 126 is formed close to the low pressure vane insertion hole 124h into which the low pressure vane 124 (shown in FIG. 5) is inserted. This is because as the low pressure inlet hole 126 is farther from the low pressure vane 124 (shown in FIG. 5), a dead volume that does not contribute to the compression of the refrigerant in the inner space of the low pressure cylinder 121 increases.

In addition, the intermediate pressure inlet groove 130a of the high pressure cylinder 131 is not formed to penetrate from the lower part to the upper part of the high pressure cylinder 131, and communicates with the internal space of the high pressure cylinder 131 from the lower part of the high pressure cylinder 131. It is formed obliquely. At this time, the intermediate pressure inlet groove 130a is formed close to the high pressure vane hole 134h into which the high pressure vane (not shown) is inserted. As in the low pressure compression assembly, since the intermediate pressure inlet groove 130a is formed close to the high pressure vane (not shown), it is possible to reduce the dead volume in the space inside the high pressure cylinder 131.

The low pressure vanes 124 and the high pressure vanes (not shown) are located on the same axis. Therefore, the intermediate pressure communication hole 161a formed in the lower bearing 161 and the intermediate pressure inflow groove 130a formed in the high pressure cylinder 131 are not formed on the same axis, and horizontal positions are formed to be spaced apart from each other. In the third embodiment of the present invention, in order to connect the intermediate pressure communication hole 161a of the lower bearing 161 and the intermediate pressure communication hole 130a of the high pressure cylinder 131, the intermediate pressure communication hole of the low pressure cylinder 121 is connected. The intermediate pressure communication hole 140a of the 120a and the intermediate plate 140 is formed in a substantially spiral shape. The intermediate pressure communication hole 120a of the low pressure cylinder 121 and the intermediate pressure communication hole 140a of the intermediate plate 140 are formed to overlap each other in a spiral. That is, the intermediate pressure communication hole 120a of the low pressure cylinder 121 and the intermediate pressure communication hole 140a of the intermediate plate 140 overlap to form a spiral communication hole. At this time, one end of the spiral communication hole overlaps the intermediate pressure communication hole 161a of the lower bearing 161, and the other end overlaps the intermediate pressure inlet groove 130a of the high pressure cylinder 131. Here, one end of the intermediate pressure communication hole 120a of the low pressure cylinder 121 penetrates to be connected to the intermediate pressure communication hole 161a of the lower bearing 161. That is, the intermediate pressure communication hole 120a of the low pressure cylinder 121 is formed such that one end contacting the intermediate pressure communication hole 161a of the lower bearing 161 penetrates in the vertical direction of the low pressure cylinder 121, and intermediate pressure communication is performed. The remaining portion of the hole 120a is formed in a spiral shape as the lower portion of the intermediate pressure communication hole 120a gradually increases from one end to the other end. In addition, the intermediate pressure communication hole 140a of the intermediate plate 140, on the other hand, the other end of the spiral communication hole, that is, the other end overlapping the intermediate pressure inlet groove 130a of the high pressure cylinder 130 is perpendicular to the intermediate plate 140. It is formed to penetrate in the direction. In addition, as the upper end portion of the intermediate pressure communication hole 120a gradually increases from one end overlapping with the intermediate pressure communication hole 161a of the lower bearing 161 to the other end, it is formed in a spiral shape as a whole.

When the intermediate pressure communication hole 120a of the low pressure cylinder 121 and the intermediate pressure communication hole 140a of the intermediate plate 140 are formed in a spiral shape, the refrigerant is formed in the intermediate pressure communication hole 120a and the middle of the low pressure cylinder 121. The resistance received along the intermediate pressure communication hole 140a of the plate 140 is reduced. Of course, the intermediate pressure communication hole (120a) of the low pressure cylinder 121 and the intermediate pressure communication hole (140a) of the intermediate plate 140 is not only a spiral, but also a circular arc-like shape that does not change the height of the top or bottom. It may be formed as.

Further, when the intermediate pressure communication hole 120a of the low pressure cylinder 121 and the intermediate pressure communication hole 140a of the intermediate plate 140 are formed in a spiral or arc shape, the intermediate pressure communication holes 120a and 140a of the spiral or arc shape are formed. Fastening holes 120b and 140b may be formed in the central portion of the. The lower bearing 161, the low pressure cylinder 121, the intermediate plate 140, the high pressure cylinder 131, and the upper bearing 162 are generally fastened through bolts. At this time, the fastening holes 161b, 120b, 130b, 140b, and 162b to which the bolts are fastened are the refrigerant inlet pipe 151, the medium pressure communication hole 161a, 120a, 130a, and 162a, the medium pressure inlet groove 140a, and the middle. Various members such as the pressure discharge hole 127 and the inner flow path 180 should be avoided. In addition, the fastening holes 161b, 120b, 130b, 140b, and 162b should be formed in at least three places, and should be able to evenly distribute the fastening force to the entire compressor assembly 105. In this case, the intermediate pressure communication hole 120a of the low pressure cylinder 121 and the intermediate pressure communication hole 140a of the intermediate plate 140 are formed of the intermediate pressure communication hole 161a of the lower bearing 161 and the high pressure cylinder 131. Since the length is longer than that of the intermediate pressure inlet groove 130a, it prevents the formation of a plurality of fastening holes 161b, 120b, 130b, 140b and 162b. Therefore, when the intermediate pressure communication hole 120a of the low pressure cylinder and the intermediate pressure communication hole 140a of the intermediate plate 140 are formed in a spiral or arc shape, the fastening hole 161b, 120b, 130b, 140b, 162b can be formed, which is advantageous for distributing a plurality of fastening holes 161b, 120b, 130b, 140b, 162b in the entire compressor assembly 105.

9 is a view showing an example of the rotary shaft of the rotary two-stage compressor according to the present invention, Figure 10 is a view showing an example of the installation structure of the rollers on the rotary shaft of the rotary two-stage compressor according to the present invention. The low pressure eccentric portion 122 and the high pressure eccentric portion 132 are coupled to the rotary shaft 113. The low pressure eccentric 122 and the high pressure eccentric 132 are coupled to the rotating shaft 113 with a phase difference of generally 180 kHz to reduce vibration. In addition, the rotating shaft 113 is a hollow shaft having an empty inside, and has an oil communication hole 113a at the lower portion of the low pressure eccentric portion 122 and the upper portion of the high pressure eccentric portion 132. In addition, the rotation shaft 113 is formed of a hollow shaft, the inner portion (113h) is inserted into the stirrer (113b) of the thin plate bent in a spiral. The stirrer 113b is fitted to the inside 113h of the rotating shaft 113, and rotates together with the rotating shaft 113 when the rotating shaft 113 rotates. As the stirrer 113b rotates together by the rotation of the rotary shaft 113, oil filled in the lower portion of the sealed container 101 (shown in FIG. 4) is along the inside of the rotary shaft 113 along the stirrer 113b. A portion of the lower pressure cylinder 121, the intermediate plate 140 and the high pressure cylinder 131 through the oil communication hole (113a) formed in the rotary shaft 113, the low pressure roller 123 and the high pressure roller ( 133) and the like.

In particular, considering that the pressure in the compression space of the low pressure compression assembly 120 (shown in FIG. 4) is lower than the pressure in the compression space of the high pressure compression assembly 130 (shown in FIG. 4) the low pressure compression assembly 120 (FIG. 4). The compression space of the high pressure compression assembly 130 (shown in FIG. 4) is wider than that of the high pressure compression assembly 130 (for the low pressure eccentric portion 122 and the high pressure eccentric portion 132). However, the low pressure eccentric 122 is preferably formed at least about 40% longer in the axial direction than the high pressure eccentric 132. Accordingly, as the low pressure eccentric 122 is formed thicker than the high pressure eccentric 132, the friction loss between the low pressure eccentric 122 and the low pressure roller 123 is also greater than that of the high pressure eccentric 132. It is more preferable to reduce the relative friction loss by reducing the contact area between the low pressure eccentric 122 and the low pressure roller 123. For example, a belt-shaped friction reducing groove 122a may be formed at the center of the outer circumferential surface of the low pressure eccentric portion 122 in the circumferential direction.

Of course, in order to reduce the friction loss in the low pressure compression assembly 120 (see FIG. 4), the friction reducing groove 122a may also be formed in the inner diameter of the low pressure roller 123, but the low pressure roller 123 may have a low pressure eccentric portion ( It is more preferable that the friction reducing groove 122a is formed at the outer diameter of the low pressure eccentric portion 122 rather than the inner diameter of the low pressure roller 123 in order not only to have a relatively thin thickness as compared with the 122). Furthermore, although the friction reducing effect is inferior to the low pressure compression assembly 120 (shown in FIG. 4), the high pressure eccentric portion 132 and the high pressure roller ( In order to reduce the contact area between the 133, a friction reducing groove (not shown) may also be formed in the outer diameter of the high-pressure eccentric portion 132.

11 to 13 are graphs showing the input power according to the friction reducing groove size, which is the main part of the present invention. More specifically, when the axial length H of the friction reducing groove 122a is constant, the ratio of the axial length E of the low pressure eccentric portion 122 to the axial length L of the low pressure roller 123. As the E / L increases, the input power increases as the contact area between the low pressure eccentric portion 122 and the low pressure roller 123 increases, while the low pressure eccentric portion with respect to the axial length L of the low pressure roller 123 is increased. As the axial length (E) ratio (E / L) of the 122 decreases, the contact area between the low pressure eccentric 122 and the low pressure roller 123 is reduced, so that the effective power transmission is not achieved. do. Accordingly, as shown in FIG. 11, the ratio (E / L) of the axial length E of the low pressure eccentric 122 to the axial length L of the low pressure roller 123 is set within a range of 0.56 to 0.62. It is effective to reduce the power input to the rotary two stage compressor.

In addition, when the axial length L of the low pressure roller 123 is constant, the ratio of the axial length H of the friction reducing groove 122a with respect to the axial length E of the low pressure eccentric part 122 H / E) as the contact area between the low pressure eccentric portion 122 and the low pressure roller 123 is reduced, the effective power transmission is not achieved, the input power is increased, while the axial length (E) of the low pressure eccentric portion 122 As the axial length (H) ratio (H / E) of the friction reducing groove (122a) with respect to the () decreases, the input power increases as the contact area between the low pressure eccentric portion 122 and the low pressure roller 123 increases. do. Accordingly, as shown in FIG. 12, the ratio (H / E) of the axial length H of the friction reducing groove 122a to the axial length E of the low pressure eccentric portion 122 is within the range of 0.7 to 0.8. It is effective to reduce the power input to the rotary two stage compressor.

Further, when the axial lengths H, E, and L of the friction reducing groove 122a, the low pressure eccentric portion 122, and the low pressure roller 123 are constant, the depth (in the radial direction of the friction reducing groove 122a) The deeper the depth W, the lower the strength of the rotating shaft 113, while the shallower the depth W in the radial direction of the friction reducing groove 122a, the lower pressure eccentric 122 and the lower pressure roller 123 are. It can be rotated in contact with each other, reducing the effect of reducing frictional losses. Accordingly, as shown in FIG. 13, the friction reducing groove 122a is input to the rotary two-stage compressor in which the depth W is set within the range of 0.01 to 1 mm in the radial direction from the outer diameter of the low pressure eccentric portion 122. Effective for reducing power

In the above, the present invention has been described in detail by way of examples based on the embodiments of the present invention and the accompanying drawings. However, the scope of the present invention is not limited by the above embodiments and drawings, and the scope of the present invention will be limited only by the contents described in the claims below.

The rotary two-stage compressor according to the present invention configured as described above has a contact between the low pressure eccentric portion and the low pressure roller even if the low pressure eccentric portion and the low pressure roller of the low pressure compression assembly are formed larger than the high pressure eccentric portion and the high pressure roller of the high pressure compression assembly. Friction reducing grooves are provided to reduce the area, thereby reducing frictional losses between the low pressure eccentrics and the low pressure rollers, which have a relatively large contact area, thereby reducing component wear and reducing input power. There is an advantage to this.

Claims (10)

chest; A rotating shaft which is provided in the sealed container and supplies oil while transmitting rotational force; At least two compression assemblies including a roller engaged with the rotation shaft and a cylinder for compressing the refrigerant while the roller rolls inwardly by the rotation of the rotation shaft; And, And a friction reducing groove formed between the rotating shaft and the roller to reduce the friction area between the rotating shaft and the roller. The method of claim 1, The axis of rotation comprises at least two eccentrics which are eccentric in a different direction to the axis of rotation such that the roller is engaged with the outer circumferential surface, The friction reduction groove is a rotary two-stage compressor, characterized in that formed on the outer peripheral surface of the eccentric portion. The method of claim 2, The friction reduction groove is a rotary two-stage compressor, characterized in that formed in a strip shape along the circumferential direction in the center of the outer peripheral surface of the eccentric portion. The method of claim 1, The compression assembly includes: a low pressure compression assembly for compressing the low pressure refrigerant to medium pressure while the low pressure roller engaged with the rotating shaft rolls inside the low pressure cylinder; And a high pressure compression assembly configured to compress the medium pressure refrigerant to a high pressure while the high pressure roller engaged with the rotating shaft rolls the inside of the high pressure cylinder. The method of claim 4, wherein The rotating shaft includes a low pressure eccentric part eccentrically in one direction on the rotating shaft so that the low pressure roller is engaged with the outer circumferential surface, and a high pressure eccentric part eccentrically in a different direction from the low pressure eccentric part on the rotating shaft so that the high pressure roller is engaged with the outer circumferential surface The friction reduction groove is a rotary two-stage compressor, characterized in that formed on the outer peripheral surface of the low-pressure eccentric portion. The method of claim 5, wherein The low pressure eccentric unit is a rotary two-stage compressor, characterized in that the axial length is formed longer than the high pressure eccentric unit. The method of claim 6, The friction reduction groove is a rotary two-stage compressor, characterized in that formed in a strip shape along the circumferential direction in the center of the outer peripheral surface of the low-pressure eccentric portion. The method according to any one of claims 5 to 7, The axial length of the low pressure eccentric portion with respect to the axial length of the low pressure roller is a rotary two-stage compressor, characterized in that set in the range 0.56 ~ 0.62. The method according to any one of claims 5 to 7, The rotary two-stage compressor, characterized in that the axial length of the friction reducing groove with respect to the axial length of the low pressure eccentric portion is set within the range of 0.7 ~ 0.8. The method according to any one of claims 5 to 7, The friction reduction groove is a rotary two-stage compressor, characterized in that the depth is set within the range 0.01 ~ 1mm in the radial direction from the outer diameter of the low pressure eccentric portion.

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