JP5677196B2 - Rotary compressor - Google Patents

Description

  The present invention relates to a rotary compressor used in a refrigeration cycle using a heat pump such as a refrigeration / refrigeration air conditioning device or a hot water supply device.

  In a conventional hermetic rotary compressor, an electric motor composed of a stator and a rotor is located at the top, and a compression mechanism driven by a rotating shaft connected to the electric motor is located below the electric motor. The refrigerant is sucked into the compression mechanism section and is compressed to a high pressure (discharge pressure) by the compression mechanism section, and is discharged from the discharge pipe fixed to the sealed container to the outside of the sealed container. High pressure refrigerant is discharged into the refrigeration cycle.

  The compression mechanism reciprocates in a cylinder, a roller fitted in an eccentric portion of the crankshaft provided in the cylinder, and a slot provided in the cylinder following the eccentric rotation of the roller. The vane is composed of an upper bearing and a lower bearing that close the both end faces of the cylinder and support the crankshaft.

  The crankshaft is provided with an oil passage hole at the center of rotation in the axial direction and an oil supply hole communicating with the bearing side. The eccentric part of the crankshaft is provided with an oil supply hole communicating with the inner peripheral part of the roller, and an oil groove is provided on the outer peripheral part.

  The bottom of the sealed container is an oil sump, which stores refrigerating machine oil that lubricates the sliding portion of the compression mechanism and seals the compression chamber. The lower part of the crankshaft is immersed in the oil in the oil reservoir in the oil sump, and the centrifugal pump is driven by the rotation of the crankshaft, so that the refrigeration oil is pumped into the oil passage hole formed inside the crankshaft, and the sliding of the compression mechanism It is supplied to places. The crankshaft is supported in the radial direction by an upper bearing and a lower bearing of the compression mechanism portion that closes the top and bottom of the compression chamber.

  The main sliding portions of the compression mechanism include a crank lower shaft and a lower bearing, a crank eccentric shaft and a roller inner peripheral portion, a crank upper shaft and an upper bearing, and the like.

  Refrigeration oil is supplied between the crank lower shaft and the lower bearing through the oil supply hole of the crank lower shaft, and refrigeration oil is supplied between the crank eccentric shaft and the roller through the oil supply hole of the crank eccentric shaft. . A part of the refrigerating machine oil used for lubricating the crank eccentric shaft and the roller inner peripheral portion is supplied to the crank upper shaft and the upper bearing.

  Refrigerating machine oil supplied to lubricate the sliding part of the cylindrical upper bearing and crankshaft of the upper bearing body extending toward the rotor is lubricated from the upper end of the upper bearing and crankshaft, which is the upper end of the upper bearing after lubrication. It is discharged so as to be ejected. Since the refrigeration oil is supplied by the centrifugal pump action, the amount of refrigeration oil per unit time supplied to the upper bearing is the rotation speed, especially when the motor is capable of variable speed operation and the compressor rotation speed exceeds 60 rps. Accordingly, the amount of refrigerating machine oil discharged from the upper end of the upper bearing also increases accordingly.

  The refrigeration oil discharged from the upper bearing end passes through the air gap, which is the radial gap between the stator and rotor of the motor, enters the upper space of the motor and the secondary space in the sealed container, and communicates with this secondary space. It is discharged from the discharge pipe to the refrigeration cycle outside the sealed container.

  The following problems arise when the amount of refrigerating machine oil supplied to the sliding portion of the compression mechanism is small.

  The amount of refrigeration oil required to lubricate each sliding part of the compression mechanism is reduced, causing the sliding part to be poorly lubricated, increasing the sliding loss, reducing the compressor efficiency, and causing the sliding part to wear. Or damage it. In the worst case, the sliding portion is seized and the rotary shaft is locked, and the compressor cannot be operated.

  Further, the sealing performance of the compression chamber of the compression mechanism portion is lowered, and the compressor efficiency is lowered due to an increase in leakage loss.

  Further, if the amount of the refrigerating machine oil supplied to the sliding portion of the compression mechanism portion is too large, the following problem occurs.

  The amount of refrigerating machine oil discharged from the upper end of the upper bearing increases, and the oil discharged from the upper bearing upper end enters the secondary space in the sealed container through the air gap and communicates with the secondary space. Since it is discharged from the discharge pipe to the refrigeration cycle outside the sealed container, the heat transfer efficiency is lowered in the heat exchanger on the refrigeration cycle, and the efficiency of the entire refrigeration cycle apparatus is lowered.

  In a conventional rotary compressor, an oblique groove is provided on the sliding surface of the eccentric part of the crankshaft, and the sectional area of the groove is gradually changed from the upstream side to the downstream side. (For example, Patent Document 1).

Japanese Patent Laid-Open No. 2-130292 (page 5, upper right row, lines 11 to 20; FIGS. 2 and 5)

  However, in Patent Document 1, since the slant groove serves as a pump and discharges the lubricating oil, when the lubricating oil flows out to the refrigeration system and the amount of oil supply decreases, the crankshaft and the bearing, the eccentric part of the crankshaft As a result, the roller piston is liable to make metal contact and the sliding becomes severe.

  The present invention has been made to solve the above-described problems. The lubrication amount is ensured so that each sliding portion of the compression mechanism section does not cause poor lubrication and is discharged from the end of the upper bearing. An object of the present invention is to provide a highly efficient and highly reliable compressor by suppressing the amount of refrigeration oil to be discharged and reducing the amount of refrigeration oil discharged from the outside of the compressor to the refrigeration circuit.

The rotary compressor according to the present invention includes a drive unit having a crankshaft and a sealed container that houses a compression mechanism unit driven by the drive unit via the crankshaft, and the compression mechanism unit includes a fluid Inflow, a roller fitted in the eccentric part of the crankshaft, and provided in the cylinder, and an upper bearing and a lower bearing for closing the both end faces of the cylinder and supporting the crankshaft. In addition, an oil groove is provided in a part of the outer periphery of the eccentric portion over the entire width in the axial direction, the lower end of the oil groove communicates with the bearing portion of the lower bearing, and the cross-sectional shape of the oil groove is the oil groove The oil groove is reduced from the lower end to the upper end from the lower end to the upper end .

  According to this invention, since an appropriate amount of refrigerating machine oil can be supplied to the compression mechanism section, the sealing performance and lubricity of the compression mechanism section can be ensured, and each sliding portion of the compression mechanism section has poor lubrication. There is an effect of obtaining a highly efficient and highly reliable rotary compressor that does not occur.

It is a longitudinal cross-sectional view of the rotary compressor which shows Embodiment 1 of this invention. It is principal part sectional drawing of the rotary compressor shown in FIG. FIG. 2 is a cross-sectional view for explaining a compression mechanism of the rotary compressor shown in FIG. 1. It is a perspective view of the oil groove of the crankshaft eccentric part shown in FIG. 1, FIG.

[Embodiment 1]
FIG. 1 is a longitudinal sectional view showing a hermetic rotary compressor according to Embodiment 1 for carrying out the present invention, and FIG. 2 is a sectional view of a main part of the rotary compressor shown in FIG. 3 is a cross-sectional view for explaining the compression mechanism of the compression mechanism 1 of the rotary compressor shown in FIG. 1, and FIG. 4 is an eccentric oil groove of the crankshaft which is the main part of the present invention. FIG.

  As shown in FIGS. 1 and 3, the rotary compressor includes a compression mechanism 1 inside a sealed container 70, a stator 51 that rotates the compression mechanism 1 through a crankshaft 2, and a rotor 52. A gas-liquid separator 90 that houses the electric motor 50 and is held on the outer surface of the sealed container 70 is provided. The compression mechanism unit 1 is disposed below the electric motor 50, and a space between the electric motor 50 and the compression mechanism unit 1 is a primary space 80. An oil sump 75 is provided at the bottom of the hermetic container 70 for storing refrigerating machine oil that is supplied to the compression mechanism unit 1 and used for lubrication of each sliding portion of the compression mechanism unit 1 and sealing of the compression chamber.

  The sealed container 70 is hermetically sealed by joining an upper lid 72 and a bottom lid 73 to a cylindrical container 71 that is open at the top and bottom by welding or the like. A leg 74 for allowing the rotary compressor to stand by itself is joined to the bottom surface of the bottom lid 73. The sealed container 70 may have a two-part configuration in which an upper lid 72 is joined to a bottomed cylindrical container 71 formed by drawing or the like. Carbon dioxide or HFC refrigerant is used as the refrigerant compressed by the rotary compressor. As the refrigerating machine oil of the sump 75, PAG (polyalkylene glycol) oil is often used when the refrigerant is carbon dioxide, and ether oil, ester oil or alkylbenzene oil is often used when the refrigerant is HFC refrigerant.

  The electric motor 50 includes a stator 51 and a rotor 52. The electric motor 50 is variable speed compatible, and changes the number of rotations according to the load of the refrigeration cycle apparatus using this rotary compressor. Depending on the operating environment of the refrigeration cycle apparatus, high-speed operation is also performed such that the rotational speed exceeds 60 rps. Between the outer periphery of the rotor 52 and the inner periphery of the stator 51, a radial gap called an air gap is provided substantially uniformly over the entire periphery. Since the motor efficiency decreases when the air gap 58 is wide, the air gap 58 is usually set to a narrow width of about 0.3 to 1.0 mm. Here, the width of the air gap 58 is half of the difference between the inner diameter of the stator 51 and the outer diameter of the rotor 52, and represents a radial gap. The air gap 58 serves as a flow path for the high-pressure refrigerant compressed by the compression mechanism unit 1.

  In the stator 51, a coil is wound in a concentrated winding manner on the inner teeth of substantially annular electromagnetic steel plates that are stacked and fixed together by caulking, and the outer periphery of the laminated electromagnetic steel plates is a cylindrical container 71 of a sealed container 70. It is fixed to the inner wall directly by shrink fitting.

  The rotor 52 includes a rotor core 53 in which annular electromagnetic steel plates are laminated and fixed by caulking, and an upper balancer 54 and a lower balancer 55 fixed to upper and lower end surfaces of the rotor core 53, respectively. The upper balancer 54 and the lower balancer 55 are mounted to statically and dynamically balance the unbalance of the force due to the eccentric rotation in the compression mechanism unit 1, and the rotor is constituted by caulking pins (not shown). The core 53 is caulked and fixed. A permanent magnet such as a rare earth magnet or a ferrite magnet is embedded in the rotor core 53.

  The rotor 52 is provided with a plurality of air holes 56 as flow paths for high-pressure refrigerant compressed by the compression mechanism unit 1 so as to communicate with the upper and lower sides of the rotor 52. The rotor core 53 is shrink-fitted with the crankshaft 2 on the inner periphery of the laminated electromagnetic steel plates. When power is supplied to the stator 51, the crankshaft 2 rotates integrally with the rotor 52. . A glass terminal 57 is welded and fixed to the upper lid 72 of the hermetic container 70, and the glass terminal 57 and the stator 51 are connected by lead wires. Electric power supplied from outside relays the glass terminal 57 to the electric motor 50. Is granted.

  A space between the sealed container 70 and the electric motor 50 in the upper part of the electric motor 50 (opposite side to the compression mechanism unit 1) is a secondary space 81. A discharge pipe 76 is provided in the secondary space 81 and is fixedly bonded to the upper lid 72. One of the discharge pipes 76 opens into the secondary space 81 and the other opens to the outside of the sealed container 70, and discharges the high-pressure refrigerant compressed by the compression mechanism unit 1 from the inside of the sealed container 70 to the outside. The other of the discharge pipes 76 is connected to a connection pipe in a high pressure region of a refrigeration cycle that uses this rotary compressor.

  As shown in FIG. 3, the compression mechanism 1 includes a plate-like vane in which a roller 3 fitted in an eccentric portion 2 a of a crankshaft 2 is accommodated in a cylinder chamber that is an inner space of the cylinder 4 and contacts the outer periphery of the roller 3. Reference numeral 5 denotes a rotary compression mechanism that partitions the cylinder chamber of the cylinder 4 into a suction chamber 6 and a compression chamber 7 and performs compression by reducing the volume of the compression chamber 7 by eccentric rotation of the roller 3. The vane 5 fits into a vane groove 4 a formed in the cylinder 4, and reciprocates in the vane groove 4 a as the roller 3 is eccentrically rotated by the rotation of the crankshaft 2.

  An upper bearing body 10 that closes the upper sides of the suction chamber 6 and the compression chamber 7 is bolted to the cylinder 4 on the upper surface of the cylinder 4. The upper bearing body 10 has a cylindrical upper bearing 11 that extends in the direction of the rotor 52 and supports the crankshaft 2 in the radial direction. Further, a lower bearing body 12 that closes the lower side of the suction chamber 6 and the compression chamber 7 is bolted to the cylinder 4 on the lower surface of the cylinder 4. The lower bearing body 12 has a cylindrical lower bearing 13 that extends in the direction of the bottom of the sealed container 70 and supports the crankshaft 2 in the radial direction together with the upper bearing 11. The crankshaft 2 is supported in the radial direction by bearings on the upper and lower sides of the cylinder 4. The lower bearing body 12 is an upper end surface whose outer peripheral side is in contact with the lower surface of the cylinder 4, and supports the lower end surface of the eccentric portion 2 a to support the crankshaft 2 to which the rotor 52 is fixed, as well as the roller 3. And the vane 5 are also supported in the axial direction. The upper bearing body 10 and the lower bearing body 12 are also components that constitute the compression mechanism section 1.

  A discharge muffler 8 made of sheet metal is fixed to the upper bearing body 10 so as to cover a part of the upper surface of the upper bearing body 10, and a small-capacity silencing space is formed between the upper bearing body 10 and the upper surface. The silencing space communicates with the compression chamber 7 via a discharge valve (not shown) installed in the upper bearing body 10. The compression mechanism portion 1 is fixed by joining the outermost peripheral surface of the upper bearing body 10 or the cylinder 4 to the cylindrical container 71 of the sealed container 70 by welding or caulking.

The gas-liquid separator 90 temporarily stores the liquid refrigerant so that the liquid refrigerant is not directly sucked into the compression chamber of the compression mechanism unit 1 during a transient operation state or the like, and at the same time, with the volume of the cylindrical container 91. It silences the pulsation of the low-pressure refrigerant, and is integrally held by a receiver fixed to the cylindrical container 71.
In the gas-liquid separator 90, a low-pressure connection pipe 92 connected to a connection pipe in a low-pressure region of a refrigeration cycle using the rotary compressor is joined to the upper portion of the container 91. Further, a suction pipe 93 that joins the gas refrigerant inside the container 91 and sucks the gas refrigerant into the suction chamber 6 of the compression mechanism unit 1 is joined to the bottom surface of the container 91. When the low-pressure refrigerant flowing into the container 91 from the low-pressure connection pipe 92 is in a two-phase state of liquid and gas in a transient operation state or the like, the liquid refrigerant is temporarily stored in the container 91, and only the gas refrigerant is stored. Is sucked into the compression mechanism 1 from the suction pipe 93.
The liquid refrigerant temporarily stored in the container 91 is then evaporated to become a gas refrigerant, and is sucked into the compression mechanism unit 1 from the suction pipe 93.

  The crankshaft 2 is formed in the approximate center of the crankshaft 2 from the lower end (end surface on the oil sump 75 side) to the axial direction (longitudinal direction of the crankshaft 2), and an oil passage hole for pumping the refrigerating machine oil of the oil sump 75 by centrifugal pump action 14 The oil passage hole 14 stops in the middle of the crankshaft 2, but may penetrate to the upper end. The crankshaft 2 is provided with a lower bearing oil supply hole 15 for supplying refrigeration oil to the lower bearing 13. The lower bearing oil supply hole 15 is at a position above the lower bearing 13, one communicating with the oil passage hole 14, and the other opening to the outer periphery of the crankshaft 2 at a sliding portion between the lower bearing 13 and the crankshaft 2. It guides refrigerating machine oil and is formed in a direction substantially orthogonal to the axial direction of the crankshaft 2. Similarly, the crankshaft 2 is provided with an eccentric shaft oil supply hole 16 for supplying refrigerating machine oil that lubricates a sliding portion with the roller 3. The eccentric shaft oil supply hole 16 communicates with an eccentric shaft oil groove 17 for conveying refrigeration oil formed across the entire width of the crankshaft 2 in the direction of the outer peripheral axis of the eccentric portion 2a. The diameters of the lower bearing oil supply holes 15 and 16 are both smaller than the diameter of the oil passage hole 14. An oil supply passage is formed by the oil passage hole 14 formed in the crankshaft 2, the lower bearing oil supply hole 15, and the eccentric shaft oil supply hole 16.

  In the rotary compressor configured as described above, as shown in FIG. 2, with respect to the eccentric shaft oil groove 17 for oil conveyance provided on the outer periphery of the eccentric portion 2a of the crankshaft 2, the lower end 17a of the eccentric shaft oil groove is The lower bearing inner diameter 13a, that is, communicates with the bearing portion of the lower bearing 13, and the cross section of the eccentric shaft oil groove 17 is reduced in the oil flowing direction.

  As shown in FIG. 2, the lower end 17 a of the oil conveying eccentric shaft oil groove provided on the outer periphery of the eccentric portion 2 a of the crankshaft 2 is communicated with the bearing portion of the lower bearing 13, thereby exiting from the lower bearing oil supply hole 15. Since the refrigeration oil is also supplied for lubrication of the sliding portion of the eccentric portion 2a and the roller 3, the amount of oil supplied to the sliding portion of the eccentric portion 2a and the roller 3 can be increased and the lubrication performance can be improved. Become.

Furthermore, regarding the eccentric shaft oil groove 17 for oil conveyance provided on the outer periphery of the eccentric portion 2a of the crankshaft 2, the cross section of the eccentric shaft oil groove 17 is directed in the direction in which the oil flows (the direction from bottom to top in FIG. 2). Since the size is reduced, the amount of the refrigerating machine oil used for lubricating the eccentric portion 2a and the roller is suppressed to the upper bearing body 10 side, and the amount discharged from the upper bearing 11 into the sealed container 70 is made appropriate. Therefore, the amount of refrigerating machine oil discharged to the refrigeration cycle outside the sealed container 70 can be suppressed, and the heat transfer efficiency of the heat exchanger of the refrigeration cycle can be ensured without degrading the lubrication performance of the compression mechanism unit 1. it can.
The cross-sectional shape of the eccentric shaft oil groove 17 may be continuously reduced along the oil flowing direction.

  Further, it is desirable that the groove depth of the end portion on the upper bearing side of the eccentric shaft oil groove 17 is 1.0 mm or less.

  In recent years, the working pressure of refrigerant compressed and discharged by a rotary compressor has been increased. As a refrigerant having a high operating pressure, for air conditioners, there are HFC32 and HFC mixed refrigerant in which the weight ratio of HFC32 is more than half. Recently, carbon dioxide having a higher operating pressure than these HFC refrigerants has been used mainly for hot water heaters. Since these refrigerants having a high operating pressure have a large differential pressure between high and low pressures, the compression load is large and the sliding load is large. If the load on the sliding portion is increased, the sliding portion is likely to be damaged. Therefore, it is necessary to increase the supply amount of refrigerating machine oil to the sliding portion.

  However, if the supply amount is increased, the amount of oil ejected from the end of the upper bearing 11 is increased, and the oil level of the oil sump 75 is lowered. When the oil level of the oil sump 75 is lowered, the sealing property of the circumferential surface of the vane 5 is deteriorated, and there is a problem that the performance is greatly lowered due to an increase in leakage loss.

  The present invention secures the supply amount of refrigerating machine oil necessary for lubrication of the compression mechanism section 1 and suppresses refrigerating machine oil that is discharged together with the high-pressure refrigerant to the outside of the sealed container 70, thereby increasing the oil level of the oil reservoir 75. In other words, since the amount of storage can be stably maintained and the refrigerating machine oil can be stably supplied to the sliding portion of the compression mechanism 1 without causing the refrigerating machine oil in the oil reservoir 75 to be exhausted, such an operating pressure is high. Particularly effective in the refrigerant, each sliding portion can be reliably lubricated to ensure reliability, and leakage loss can be suppressed to improve efficiency.

  The present invention is particularly effective for a refrigerant having a high operating pressure. However, even when a refrigerant other than a refrigerant having a high operating pressure, such as an HFC refrigerant or an HC refrigerant that does not include HFC32, is used, By reducing the refrigerating machine oil discharged together with the high-pressure refrigerant to the outside of the hermetic container 70, the refrigerating machine oil in the oil sump 75 can be stored in an appropriate amount and the oil level can be stably maintained. The sealing performance of the chamber 7 is enhanced, and each sliding portion of the compression mechanism 1 does not cause poor lubrication, so that a rotary compressor with high efficiency and high reliability can be obtained. As refrigeration oil, ether oil, ester oil or alkylbenzene oil is often used when the refrigerant is HFC refrigerant with a ratio of HFC32 of less than half or does not contain HFC32, and mineral oil is often used when the refrigerant is HC refrigerant. Is done.

  Further, when the electric motor 50 is variable speed compatible, the flow rate of the high-pressure refrigerant is increased, and the amount of refrigerating machine oil supplied to the upper bearing 11 is increased, so that the rotational speed of the rotary compressor exceeds 60 rps. Although the invention is particularly effective, the present invention can be applied to a compressor having a constant speed electric motor, and similar effects can be achieved.

  The rotary compressor shown in the first embodiment is a hermetic single rotary compressor having a high pressure inside and a single compression mechanism section 1, but is not limited to this form. The present invention can also be applied to a form having a plurality of stages and a form having a multistage compression mechanism that sequentially compresses by a plurality of compression mechanism units 1. Further, in the compressor of the multistage compression mechanism, the inside may be an intermediate pressure or a low pressure instead of a high pressure. The compression mechanism is not limited to the rotary type, and may be another compression mechanism such as a reciprocating type or a scroll type. Further, the present invention can also be applied to a horizontal rotary compressor in which the axial direction of the rotary shaft is the horizontal direction, and similar effects can be achieved.

  DESCRIPTION OF SYMBOLS 1 Compression mechanism part, 2 Crankshaft, 2a Eccentric part, 3 Roller, 4 Cylinder, 4a Vane groove, 5 Vane, 6 Suction chamber, 7 Compression chamber, 8 Discharge muffler, 10 Upper bearing body, 11 Upper bearing, 12 Lower bearing Body, 13 Lower bearing, 13a Lower bearing inner diameter, 14 Oil passage hole, 15 Lower bearing oil hole, 16 Eccentric shaft oil hole, 17 Eccentric shaft oil groove, 17a Lower end of eccentric shaft oil groove, 50 Electric motor, 51 Stator, 52 Rotor, 53 Rotor core, 54 Upper balancer, 55 Lower balancer, 56 Air hole, 57 Glass terminal, 58 Air gap, 70 Airtight container, 71 Cylindrical container, 72 Upper lid, 73 Bottom lid, 74 Leg, 75 Oil sump, 76 discharge pipe, 80 primary space, 81 secondary space, 90 gas-liquid separator, 91 container, 92 low pressure connection pipe, 93 suction pipe.

Claims (3)

A sealed container that houses a drive portion having a crankshaft and a compression mechanism portion driven by the drive portion via the crankshaft;
The compression mechanism includes a cylinder into which a fluid flows, a roller fitted in an eccentric portion of the crankshaft, and an upper bearing that supports the crankshaft by closing both end faces of the cylinder. And a lower bearing,
An oil groove is provided in a part of the outer periphery of the eccentric part over the entire width in the axial direction,
The lower end of the oil groove communicates with the bearing portion of the lower bearing, and the cross-sectional shape of the oil groove is reduced from the lower end to the upper end of the oil groove from the lower end to the upper end. Rotating compressor. The rotary compressor according to claim 1 , wherein the cross-sectional shape of the oil groove is continuously reduced from the lower end to the upper end of the oil groove from the lower end to the upper end of the oil groove . The rotary compressor according to claim 1 or 2, wherein the fluid is a carbon dioxide refrigerant.

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