JP2012052521A - Rotary compressor - Google Patents

Abstract

The heat of a discharge side end plate exposed to a high-temperature gas immediately after discharge is transferred to a cylinder through a contact portion, and the volume efficiency is reduced due to heating of the working fluid during suction due to the heat of the received cylinder. Or, the compression power is increased by heating the working fluid in the middle of compression, which causes a reduction in the efficiency of the compressor.
A contact surface 30a between a discharge side end plate 34 and a cylinder 30 is provided with a recess 48 to reduce a contact area, thereby increasing heat transfer resistance from the discharge side end plate and suppressing heat reception of the cylinder 30; A highly efficient compressor with minimal working fluid heating can be realized.
[Selection] Figure 3

Description

  The present invention relates to a rotary compressor used for an air conditioner, a refrigerator, a blower, a water heater, and the like.

  Conventionally, in refrigeration equipment and air conditioning equipment, a compressor that sucks in gas refrigerant evaporated in an evaporator, compresses it to the pressure necessary for condensation, and sends high-temperature and high-pressure gas refrigerant into the refrigerant circuit has been used. Has been. A rotary compressor is known as one of such compressors.

  For example, as shown in FIG. 6, the rotary compressor is one in which the electric motor 2 and the compression mechanism 3 are connected by a crankshaft 31 and stored in the hermetic container 1. The compression mechanism section 3 includes a suction chamber 49 and a compression chamber 39 formed by a cylinder 30, a discharge side end plate 34 of an upper bearing 34a that closes both end faces of the cylinder 30, and an end plate 35 of a lower bearing 35a, and a cylinder 30, a piston 32 fitted to an eccentric portion 31 a of a crankshaft 31 supported by an upper bearing 34 a and a lower bearing 35 a, and a reciprocating motion following the eccentric rotation on the outer periphery of the piston 32. Is provided with a vane 33 that partitions the suction chamber 49 and the compression chamber 39. The crankshaft 31 is provided with an oil hole 41 in the axial line portion, and oil supply holes 42 and 43 communicating with the oil hole 41 are provided on the wall portions of the upper bearing 34a and the lower bearing 35a, respectively. An oil supply hole 44 communicating with the oil hole 41 is provided in the wall portion of the crankshaft 31 with respect to the eccentric portion 31a, and an oil groove 45 is formed in the outer peripheral portion. On the other hand, a suction port 40 for sucking gas toward the suction chamber 49 is opened in the cylinder 30, and a discharge port 38 for discharging gas from a compression chamber 39 formed by turning from the suction chamber 49 to the upper bearing 34 a. Has been opened. The discharge port 38 is formed as a circular hole in plan view that passes through the upper bearing 34a, and a discharge valve 36 that is released when a pressure of a predetermined magnitude or more is provided on the upper surface of the discharge port 38. And a cup muffler 37 that covers the discharge valve 36. On the suction chamber side, the sliding contact portion of the piston 32 passes through the suction port 40 and moves away while gradually expanding the suction chamber, and gas is sucked into the suction chamber from the suction port 40. On the other hand, on the compression chamber side after the working fluid is closed, the sliding portion of the piston 32 approaches the discharge port 38 while gradually reducing the compression chamber 39, and when the pressure is compressed to a predetermined pressure or higher, the discharge valve 36 is reached. Is opened, gas flows out from the discharge port 38, and is discharged from the cup muffler 37 into the sealed container 1.

  On the other hand, the eccentric part 31a of the crankshaft 31, the discharge side end plate 34 of the upper bearing 34a, the space 46 surrounded by the inner peripheral surface of the piston 32, the eccentric part 31a of the crankshaft 31 and the end plate 35 of the lower bearing 35a. A space 47 surrounded by the inner peripheral surface of the piston 32 is formed. Lubricating oil leaks into the spaces 46 and 47 from the oil hole 41 through the oil supply holes 42 and 43. The spaces 46 and 47 are almost always higher than the pressure inside the compression chamber 39.

  Further, the height of the cylinder 30 must be set slightly larger than the height of the piston 32 so that the piston 32 can rotate eccentrically. As a result, the end face of the piston 32 and the discharge side end plate 34, There is a gap between the end plate 35. Therefore, the lubricating oil leaks from the spaces 46 and 47 to the compression chamber 39 and the suction chamber 49 through the gap. The role of the lubricating oil is to prevent the working fluid during compression from leaking from the compression chamber 39 to the suction chamber 49 in addition to the purpose of smoothing the sliding between the members and preventing seizure.

In the rotary compressor as described above, the sucked low-pressure / low-temperature gas becomes a high-pressure / high-temperature gas until it is discharged from the discharge port 38, and the compression mechanism section 3 adjacent to the high-pressure / low-temperature gas also has a substantially high temperature side. It is close to temperature. However, when the sucked gas comes into contact with the cylinder 30, the discharge side end plate 34, the piston 32, the vane 33 and the like in a high temperature state, the density reduction due to the suction gas heating is caused in the suction chamber, and the pressure due to the compression gas heating is caused in the compression chamber. As a result, an increase occurs, resulting in a problem that the volume efficiency of the compressor is reduced and the compression power is increased.

  With respect to the above problem, Patent Document 1 devises a method of fastening by sandwiching a heat insulating plate between an end plate and a cylinder for the purpose of suppressing heat conduction in the axial direction. Moreover, in the compressor described in the other patent document 2, the heat insulation space which penetrates in a cylinder axial direction is provided in order to suppress the heat conduction of a cylinder radial direction, and the thermal resistance to the inside and outside of a cylinder is raised.

JP-A-2-140486 Japanese Patent Laid-Open No. 1-253587

  In the configuration of Patent Document 1, the heat conduction from the end plate side can be greatly reduced by the heat insulating plate, but the sliding friction between the heat insulating plate and the piston end surface is increased or the sealing performance is deteriorated. And there is a problem that the material cost is high. Moreover, in the structure of the said patent document 2, since it is a heat insulation space structure which raises the thermal resistance inside and outside a cylinder, heat transfer from an end plate side cannot fully be suppressed, and cylinder rigidity also falls, Therefore, a reliability surface There is also a problem.

  The present invention solves the above-described conventional problems. By providing a space in the contact portion between the discharge side end plate and the cylinder and reducing the contact area, the heat of the end plate adjacent to the high temperature discharge gas is transferred to the cylinder. It is an object of the present invention to provide a compressor that can suppress the transmission and realize a high volumetric efficiency by lowering the temperature of the cylinder, and can also reduce the compression power.

  In order to solve the above-described conventional problems, the rotary compressor of the present invention is provided with a recess on the discharge side end plate side or the cylinder side of the contact surface of the discharge side end plate exposed to the high temperature discharge gas and the cylinder, thereby reducing the contact area. By making it small, it can suppress that the heat | fever of a discharge side end plate moves to a cylinder, As a result, the heating from a cylinder to a working fluid can be suppressed.

  The compressor of the present invention can achieve high volumetric efficiency by suppressing heating of the working fluid during suction due to a decrease in cylinder temperature, and can simultaneously reduce the required power by suppressing heating during compression.

The longitudinal cross-sectional view of the rotary compressor in Embodiment 1 of this invention The expanded sectional view of the compression mechanism part of the rotary compressor in Embodiment 1 of this invention Assembly drawing of compression mechanism section in embodiment 1 of the present invention The figure which shows the temperature distribution of the cylinder height direction in Embodiment 1 of this invention. The expanded sectional view of the compression mechanism part of the rotary compressor in Embodiment 2 of this invention Vertical section of a general rotary compressor

1st invention has at least 1 cylinder which takes in fluid to be compressed, and a plurality of end plates which block both end faces of the cylinder, and discharge side end plates which partition the discharged working fluid from the cylinders among the end plates Is a rotary compressor characterized in that the contact surface with the cylinder is provided with a recess to reduce the contact area, and it is difficult to transfer the heat of the discharge side end plate exposed to the high temperature fluid to the cylinder. By doing so, heating of the working fluid during suction or compression can be suppressed, and volumetric efficiency can be improved and compression power can be reduced. Further, by providing the concave portion on the end plate side, the rigidity of the cylinder is not lowered and the reliability is not deteriorated.

  The second invention has at least one cylinder that takes in the fluid to be compressed and a plurality of end plates that close both end faces of the cylinder, and the cylinder partitions the discharged working fluid from the cylinder in the end plate. A rotary compressor characterized in that a concave surface is provided on the contact surface with the discharge side end plate to reduce the contact area, and the cylinder is difficult to receive heat from the discharge side end plate exposed to high temperature fluid and becoming high temperature. As a result, heating of the working fluid during suction or compression can be suppressed, and volumetric efficiency can be improved and compression power can be reduced. Further, by providing the concave portion on the cylinder side, the discharge side end plate can be configured with the minimum necessary thickness, and a compressor excellent in cost can be realized.

  In the third aspect of the invention, in particular, in the rotary compressor of the second aspect of the invention, by making the depth of the recess within 20% of the cylinder height, an unnecessary reduction in cylinder rigidity and deterioration in reliability are not caused. The wall thickness of the discharge side end plate can also be realized with a minimum.

  In the fourth aspect of the invention, in particular, in the rotary compressor of the first to third aspects of the invention, the concave portion is provided on the contact surface near the discharge port. As a result, heat conduction at the contact surface near the discharge port, which is particularly high among the discharge side end plates, can be suppressed, and the rise in cylinder temperature can be effectively suppressed. The contact ratio is high, and the reduction of the compression power due to the suppression of heating of the working fluid becomes significant.

  In the fifth aspect of the invention, in particular, in the rotary compressors of the first to fourth aspects of the invention, the cylinder or the discharge side end plate in which the recess is provided is molded from a sintered material. Sintered material can be manufactured in a complicated and highly accurate shape at the time of molding, compared to the casting material that is generally used. Compared to the case where a concave portion is provided by machining in the casting material, extra processing cost is required. It is possible to obtain the effects of the present invention without causing any problems.

  According to a sixth aspect of the invention, in particular, in the rotary compressors of the first to third and fifth aspects, the concave portion is provided on the contact surface near the suction port. The vicinity of the suction port is cooled by low-temperature suction gas, and the temperature difference with the discharge side end plate is also remarkable, so heat conduction at the contact surface can be suppressed, and cylinder temperature rise can be effectively suppressed, In the vicinity of the suction port, it takes a long time to contact the working fluid in the middle of suction, and the improvement in volumetric efficiency due to the suppression of working fluid heating becomes significant.

  In the seventh aspect of the invention, in particular, in the rotary compressor of the sixth aspect of the invention, the space formed by the recess is a closed space constituted by the discharge side end plate and the cylinder. In the heat insulating space provided in the vicinity of the suction gas, which is the coldest state inside the compressor, minimizing the heat exchange amount leads to the suppression of the heating to the suction gas, and thus the effect of the present invention is remarkably exhibited. Is.

  In an eighth aspect of the invention, in particular, in the rotary compressors of the first to seventh aspects, the discharge side end plate and the cylinder are fixed by fastening, and at least one of the recesses is provided in the vicinity of the fastening portion. Although it becomes possible to improve heat insulation performance by providing a recessed part, depending on the place and magnitude | size to provide, there exists a possibility that the sealing performance between a compression chamber and the inside of a sealed container may be reduced. Therefore, it is possible to improve the heat insulating property without deteriorating the sealing performance of the entire contact surface by providing the concave portion in the vicinity of the fastening portion having a strong fastening force.

In a ninth aspect of the invention, in particular, in the rotary compressors of the first to eighth aspects, carbon dioxide that is a high-pressure refrigerant is used as a working fluid. Since the compressor using carbon dioxide has a large pressure difference during operation, the temperature difference between the suction gas and the discharge gas is large, and the efficiency is easily lowered by heating the working fluid. Therefore, the effect of the present invention is remarkably exhibited. is there.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a longitudinal sectional view of a rotary compressor according to a first embodiment of the present invention. FIG. 2 is an enlarged view of the compression mechanism section according to the first embodiment of the present invention.

  1 and 2, the rotary compressor is one in which the electric motor 2 and the compression mechanism 3 are connected by a crankshaft 31 and stored in the sealed container 1. The compression mechanism section 3 includes a suction chamber formed by a cylinder 30 and a discharge side end plate 34 of an upper bearing 34a and an end plate 35 of a lower bearing 35a fixed by fastening bolts 7 so as to close both end faces of the cylinder 30. 49, the compression chamber 39, the piston 32 fitted in the eccentric portion 31a of the crankshaft 31 supported by the upper bearing 34a and the lower bearing 35a in the cylinder 30, and the outer periphery of the piston 32 following the eccentric rotation. And a vane 33 that reciprocates to partition the inside of the cylinder 30 into a suction chamber 49 and a compression chamber 39.

  The crankshaft 31 is provided with an oil hole 41 in the axial line portion, and oil supply holes 42 and 43 communicating with the oil hole 41 are provided on the wall portions of the upper bearing 34a and the lower bearing 35a, respectively. An oil supply hole 44 communicating with the oil hole 41 is provided in the wall portion of the crankshaft 31 with respect to the eccentric portion 31a, and an oil groove 45 is formed in the outer peripheral portion.

  On the other hand, a suction port 40 for sucking gas toward the suction portion is opened in the cylinder 30, and a discharge port 38 for discharging gas from a compression chamber 39 formed by turning from the suction chamber 49 is formed in the upper bearing 34a. Opened. The discharge port 38 is formed as a circular hole in plan view that passes through the upper bearing 34a, and a discharge valve 36 that is released when a pressure of a predetermined magnitude or more is provided on the upper surface of the discharge port 38. And a cup muffler 37 that covers the discharge valve 36.

  On the suction chamber side, the sliding portion of the piston 32 passes through the suction port 40 and moves away from the suction chamber 49 while gradually expanding, and sucks gas into the suction chamber from the suction port 40. On the other hand, on the compression chamber side, the sliding portion of the piston 32 approaches the discharge port 38 while gradually reducing the compression chamber 39, and when the pressure is compressed to a predetermined pressure or higher, the discharge valve 36 opens and the gas is discharged from the discharge port 38. Is discharged from the cup muffler 37 into the sealed container 1. The discharge port 38 is formed as a circular hole in plan view that passes through the upper bearing 34a, and a discharge valve 36 that is released when a pressure of a predetermined magnitude or more is provided on the upper surface of the discharge port 38. And a cup muffler 37 that covers the discharge valve 36. Thus, the inside of the cup muffler 37 is always filled with the discharged high temperature gas, and the upper bearing 34a receives heat from the high temperature gas and is in a high temperature state.

  On the other hand, the eccentric part 31a of the crankshaft 31, the discharge side end plate 34 of the upper bearing 34a, the space 46 surrounded by the inner peripheral surface of the piston 32, the eccentric part 31a of the crankshaft 31 and the end plate 35 of the lower bearing 35a. A space 47 surrounded by the inner peripheral surface of the piston 32 is formed. Oil leaks into the spaces 46 and 47 from the oil hole 41 through the oil supply holes 42 and 43. The pressure in the spaces 46 and 47 is almost always higher than the pressure in the compression chamber 39, and is almost in the same state as the discharge pressure.

The height of the cylinder 30 must be set slightly larger than the height of the piston 32 so that the piston 32 can slide inside. As a result, the end face of the piston 32, the upper bearing 34a, the lower bearing There is a gap between the end face of 35a. Therefore, oil leaks from the spaces 46 and 47 to the compression chamber 39 through this gap.

  FIG. 3 shows an assembly drawing of the compression mechanism portion of the rotary compressor of the present invention. In the rotary compressor configured as described above, as shown in FIG. 3, the cylinder 30 is provided with a recess 48 in the discharge side end plate 34 and the contact surface 30a. As a result, the contact area with the discharge-side end plate 34 is reduced, and the heat transfer resistance from the discharge-side end plate 34 in a high temperature state is increased, whereby the temperature of the cylinder 30 is lowered, and heating of the working fluid can be suppressed. Further, the depth of the recess 48 provided on the contact surface 30 a is set to be within 20% of the height of the cylinder 30.

  FIG. 4 shows the temperature distribution in the cylinder height direction depending on the presence / absence of a recess. By providing a recess corresponding to 20% of the cylinder height, the heat flux from the discharge side end plate is greatly reduced, and the temperature It can be confirmed that the slope is gentle. That is, a recess that is deeper than necessary reduces the radial rigidity of the cylinder 30 and causes an increase in input and deterioration of reliability. Therefore, the depth of the recess 48 is suitably within 20% of the cylinder height 30.

  Further, in the present embodiment, the discharge side end plate 34 and the cylinder 30 are fastened by the fastening bolt 7, so that the concave portion 48 is provided in the vicinity of the fastening portion 30 b by the fastening bolt 7, so that the cylinder in a high pressure state is provided. The heat insulating property of the contact surface 30a can be improved without affecting the leakage to the compression chamber or suction chamber in the low pressure state or during compression from the outer periphery via the recess 48.

  In addition, the recess 48 provided at least in the vicinity of the suction port 40 is a closed space that does not communicate with any space inside or outside the contact surface 30a when the discharge side end plate 34 is fastened. This makes it possible to achieve high volumetric efficiency by minimizing heat exchange with the suction gas inside.

  Further, in this embodiment, by configuring the cylinder with a sintered material, it becomes possible to provide the recesses 48 with high accuracy in advance at the molding stage, and there is no cost increase due to post-processing, and the effects of the invention can be obtained. it can.

  In addition, by using a high-pressure refrigerant, for example, CO2, as the working fluid, the heat conduction from the discharge side end plate 34 to the cylinder 30 is remarkable even in CO2 where the differential pressure is large and the difference between the suction temperature and the discharge temperature is large. It can be reduced, and it is possible to increase the efficiency more effectively.

(Embodiment 2)
FIG. 5 shows an enlarged cross-sectional view of the compression mechanism portion of the rotary compressor according to the second embodiment of the present invention. 5, the same components as those in FIG. 2 are denoted by the same reference numerals, and the description of the same effects is omitted.

  As shown in FIG. 5, in the rotary compressor of the present embodiment, by providing the recess 48 in the discharge side end plate 34, it is possible to suppress the heat of the discharge side end plate 34 from being transmitted to the cylinder 30. While exhibiting the same effect as in the first embodiment, the rigidity of the cylinder 30 does not change at all, so that high reliability can be realized.

  As described above, the rotary compressor of the present invention can reduce the leakage loss of the working fluid, the sliding loss and the heating loss due to excessive oiling, and increase the efficiency of the compressor. Thereby, in addition to the compressor for an air conditioner using an HFC-based refrigerant or the like, the present invention can be applied to an application such as an air conditioner using a natural refrigerant CO2 or a heat pump hot water heater.

DESCRIPTION OF SYMBOLS 1 Airtight container 2 Electric motor 22 Stator 24 Rotor 26 Air gap 28 Notch part 3 Compression mechanism part 30 Cylinder 30a Contact surface 30b Fastening part 31 Crankshaft 31a Eccentric part 32 Piston 32a Piston outer periphery 32b Piston inner periphery 33 Vane 34 Discharge side End plate 34a Upper bearing 35 End plate 35a Lower bearing 36 Discharge valve 37 Cup muffler
38 discharge port 39 compression chamber 49 suction chamber 40 suction port 41 oil hole 42 oil supply hole 43 oil supply hole 44 oil supply hole 45 oil groove 46 space 47 space 48 recess 5 upper shell 51 refrigerant discharge pipe 52 discharge space 6 oil reservoir 7 fastening bolt 100 Thrust bearing 101 Sliding member

Claims (9)

A rotary compressor comprising at least one cylinder that takes in a fluid to be compressed and a plurality of end plates that close both end faces of the cylinder,
A contact surface between the cylinder and the working fluid discharged from the cylinder and the cylinder of the discharge side end plate that partitions the cylinder, and a recess is provided on the discharge side end plate side. A rotary compressor characterized in that a contact area of the contact surface is reduced. A rotary compressor comprising at least one cylinder that takes in a fluid to be compressed and a plurality of end plates that close both end faces of the cylinder,
A contact surface between the cylinder and the working fluid discharged from the cylinder of the end plate and a discharge side end plate that partitions the cylinder, and a recess is provided on the cylinder side, and a contact area of the contact surface A rotary compressor characterized by reducing the size. The rotary compressor according to claim 2, wherein the depth of the recess is within 20% of the cylinder height. The rotary compressor according to any one of claims 1 to 3, wherein the concave portion is provided on the contact surface in the vicinity of the discharge port. The rotary compressor according to any one of claims 1 to 4, wherein the member having the concave portion is made of a sintered material. 4. The rotary compressor according to claim 1, wherein the concave portion is provided on the contact surface in the vicinity of the suction port. 5. The rotary compressor according to claim 6, wherein the space formed by the recess is a closed space formed by the discharge side end plate and the cylinder. The rotary compressor according to any one of claims 1 to 7, wherein in the compressor for fixing the discharge side end plate and the cylinder by fastening, the concave portion is provided in the vicinity of the fastening portion. The rotary compressor according to any one of claims 1 to 8, wherein the fluid to be compressed is a high-pressure refrigerant.

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