JP2006291861A - Positive displacement compressor - Google Patents

Abstract

An object of the present invention is to improve motor efficiency and reliability of a shaft support part and a sliding part while suppressing an increase in equipment cost and equipment space in a positive displacement compressor.
A positive displacement compressor stores a compression section and a drive section for driving the compression section in a hermetic container 1 and passes lubricating oil 13 stored in the hermetic container 1 through shaft support sections 3c and 9. It has an oil supply path that forcibly circulates. The pipe 20 constituting a part of the oil supply path is provided so as to be drawn out of the sealed container 1 and exchange heat with the outside air.
[Selection] Figure 1

Description

  The present invention relates to a positive displacement compressor that handles a compressible gas or liquid such as a refrigerant, and is particularly suitable for an air conditioning or refrigeration positive displacement compressor having a lubricating oil for lubricating a bearing portion or a sliding portion. It is a thing.

  Positive displacement compressors are widely used in various fields as compressors for air conditioning and refrigeration equipment. In particular, a scroll compressor, which is one form of a positive displacement compressor, has advantages such as high efficiency, high reliability, and low noise, and is actively researched and developed.

  Background art of circulating the lubricating oil in the compressor will be schematically described using a conventional scroll compressor shown in FIG. This scroll compressor has a structure in which a compression unit, a drive unit, and an oil supply path are housed in a sealed container 1.

  The basic elements of the compression unit are a fixed scroll 2, a turning scroll 3, and a frame 4. The basic components of the fixed scroll 2 are a wrap 2a, an end plate 2b, a suction port 2c, and a discharge port 2d. The basic components of the orbiting scroll 3 are a wrap 3a, an end plate 3b, a shaft support portion 3c, and a shaft support portion end surface 3d. The frame 4 is fixed to the sealed container 1 by welding or the like, and the fixed scroll 2 is fixed to the frame 4 with bolts or the like.

  The basic elements of the drive unit that drives the orbiting scroll 3 to rotate are the stator 5 and the rotor 6 when using the induction motor, the rotating shaft 7, and the Oldham ring 8 that is a main part of the rotation preventing mechanism of the orbiting scroll 3, The frame 4, the main shaft support portion 9 of the rotary shaft that rotatably engages the rotary shaft 7, and the orbiting scroll 3 and the eccentric portion of the rotary shaft 7 that are movable and rotatable in the direction of the rotary shaft. This is the scroll shaft support 3c.

  A main shaft support 9 is built in the frame 4. The stator 5 is fixed to the sealed container 1 by shrink fitting or the like. The rotor 6 is rotatably disposed in the annular stator 5. The rotating shaft 7 is rotatably supported by the main shaft support portion 9, and an intermediate portion of the rotating shaft 7 passes through the center portion of the rotor 6. The rotary shaft 7 is provided with an oil supply hole 10 penetrating the both end surfaces in the shaft center portion, and balances to cancel out the unbalanced force caused by the movement of the orbiting scroll 3 and keep the vibration of the compressor low. A balance weight 11 as a part is engaged.

  The Oldham ring 8 is disposed in the outer peripheral space 12 formed by the frame 4 and the fixed scroll 2 together with the orbiting scroll 3, and one set of two orthogonal key portions formed on the Oldham ring 8 is configured in the frame 4. The remaining one set slides on the keyway formed on the back side of the orbiting scroll wrap 3a.

  The lubricating oil 13 accumulated in the lower space of the sealed container 1 is compressed by the centrifugal pump action by the eccentric rotation operation of the oil supply hole 10, via the oil supply hole 10 provided in the shaft center part of the rotary shaft 7, and each supporting part. Oil is supplied to the parts 3c and 9.

  Subsequently, the operation of the basic elements of the scroll compressor will be described. The rotor 6 is given a rotational force by a rotating magnetic field generated by the stator 5, and the rotating shaft 7 fixed to the rotor 6 performs a rotating operation as the rotor 6 rotates. The orbiting scroll 3 is movably engaged with the eccentric portion of the rotating shaft 7 so as to be movable in the direction of the rotating shaft, and the rotating motion of the rotating shaft 7 is caused by the rotation preventing mechanism such as the Oldham ring 8 to rotate. Converted to. The volume of the compression chamber 14 formed by meshing the fixed scroll 2 and the orbiting scroll 3 decreases as the orbiting scroll 3 orbits. In the compression operation, the working fluid is sucked into the compression chamber 14 via the suction pipe 15 and the suction port 2c as the orbiting scroll 3 turns. The sucked working fluid communicates with the discharge port 2d through the compression stroke in the compression chamber 14, and is discharged through the discharge space 16 and the discharge pipe 17.

  Between the shaft support portion end surface 3d of the orbiting scroll 3 and the frame 4 facing the end surface, a seal member 18 that holds the ring-shaped groove of the frame 4 is provided. The seal member 18 has a central space 19 having an opening in the oil supply passage at the center thereof, which has a pressure substantially equal to the discharge pressure and through which the lubricating oil 13 stored at the bottom of the sealed container 1 is guided upward. The outer peripheral space 12 is divided into the outer peripheral space 12 which is maintained at an intermediate pressure between the suction pressure and the discharge pressure. A force corresponding to a pressure difference between the central space 19 and the outer peripheral space 12 is applied to the seal member 18 from the lower side to the upper side, so that the gap between the upper end surface of the seal member 18 and the shaft support portion end surface 3d of the orbiting scroll 3 is increased. In addition to sealing, a force corresponding to the pressure difference is applied from the inside to the outside to seal between the outer peripheral side of the seal member 18 and the outer peripheral surface of the ring-shaped groove of the frame 4. Thereby, the shaft support portion 3c and the main shaft support of the orbiting scroll 3 are mixed without mixing most of the lubricating oil 13 supplied from the oil supply hole 10 of the rotary shaft 7 into the central space 19 with the compressed gas in the sealed container. The portion 9 is lubricated and returned to the inner bottom portion of the sealed container 1 via the oil drain pipe 20. In such a scroll fluid machine, it is possible to obtain high bearing reliability, good compression efficiency, and low oil climbing amount. Japanese Patent Laid-Open No. 6-258308 (Patent Document 1) is cited as a patent document related to such a scroll compressor.

  Moreover, as a conventional scroll compressor, there exists a thing shown by Unexamined-Japanese-Patent No. 2004-293530 (patent document 2). This scroll compressor is configured to have an oil supply path similar to that of Patent Document 1, and a large part of the lubricating oil is supplied to each shaft support portion and returned to the bottom of the sealed container via an oil drain pipe. As an oil supply method, an oil supply pump is provided below the rotary shaft.

  Furthermore, there is a refrigerant circuit facility disclosed in Japanese Patent Application Laid-Open No. 2001-133051 (Patent Document 3) as background art for cooling the lubricating oil of the compressor. This refrigerant circuit equipment is an oil cooler dedicated circuit in which a cooling unit for lubricating oil in the compressor and a refrigerant condensing unit arranged in an environment lower in temperature than the lubricating oil are connected in a ring shape separately from the refrigerant circuit. The cooling oil is cooled by evaporating the refrigerant in the circuit dedicated to the oil cooler in the cooling unit, condensing it in the refrigerant condensing unit, and circulating it.

JP-A-6-258308 JP 2004-293530 A JP 2001-133051 A

  In the scroll compressors of Patent Document 1 and Patent Document 2, since the motor is cooled mainly by the working fluid discharged from the discharge port, it is difficult to sufficiently absorb the heat generated by the motor, and the motor operates. The temperature increased during the operation, and the motor efficiency during operation was low. In addition, the temperature of the circulating lubricating oil also rises during operation, leading to a decrease in the reliability of the shaft support portion and the sliding portion. Furthermore, the working fluid dissolves in the lubricating oil stored in the sealed container during the stop, and the melted working fluid is heated and evaporated by the heat generated by the electric motor or the like at the time of startup, so that the inside of the compressor is lower than the outside air temperature. It becomes a state. This low-temperature state continues until the working fluid is completely vaporized, which causes a delay in the start-up of the air conditioner or the refrigerator. In addition, the viscosity of the lubricating oil increases due to the low temperature, which increases the agitation loss of the shaft support portion and the sliding portion, and causes damage to the shaft support portion and the sliding portion.

  In the refrigerant equipment of patent document 3, since the independent circuit for exclusive use of an oil cooler for cooling of lubricant oil is provided, there is a subject that equipment cost and equipment space increase.

  An object of the present invention is to obtain a positive displacement compressor capable of improving the efficiency of a motor and improving the reliability of a shaft support part and a sliding part while suppressing an increase in equipment cost and equipment space.

  In order to achieve the above-described object, the present invention stores a compression unit and a drive unit that drives the compression unit in a sealed container, and forces the lubricating oil stored in the sealed container through a shaft support unit. In the positive displacement compressor having an oil supply path that circulates, a pipe that constitutes a part of the oil supply path is provided so as to be drawn out of the sealed container and to exchange heat with the outside air.

A more preferable specific configuration example of the present invention is as follows.
(1) A pipe that constitutes a part of the oil supply path after lubricating the shaft support portion is provided so as to be drawn out of the sealed container and to exchange heat with the outside air.
(2) A fan for forcibly exchanging heat with the outside air is provided for the piping drawn out of the sealed container.
(3) The heat source side heat exchanger for exchanging heat with the outside air in the heat source side heat exchanger of the refrigeration cycle in which the positive displacement compressor is used is used as a fan for forcibly exchanging heat with the outside air through the pipe drawn out of the sealed container. That was.
(4) A heater for heating the pipe drawn out of the hermetic container only at the start-up is provided.

  ADVANTAGE OF THE INVENTION According to this invention, the positive displacement compressor which can aim at the improvement of motor efficiency and the reliability of a shaft support part or a sliding part can be obtained, suppressing the increase in installation cost or installation space.

Hereinafter, a plurality of embodiments of the present invention will be described with reference to the drawings. The same reference numerals in the drawings of the respective embodiments indicate the same or equivalent.
(First embodiment)
First, a positive displacement compressor according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 3. FIG. 1 is a longitudinal sectional view showing a positive displacement compressor according to a first embodiment of the present invention. In the present embodiment, a scroll compressor that is one form of a positive displacement compressor will be described as an example.

  The scroll compressor has a structure in which a compression unit, a drive unit, and an oil supply path are housed in a sealed container 1.

  The basic elements of the compression unit are a fixed scroll 2, a turning scroll 3, and a frame 4. The basic components of the fixed scroll 2 are a wrap 2a, an end plate 2b, a suction port 2c, and a discharge port 2d. The basic components of the orbiting scroll 3 are a wrap 3a, an end plate 3b, a shaft support portion 3c, and an end surface 3d of the shaft support portion. It is. The frame 4 is fixed to the sealed container 1 by welding or the like, and the fixed scroll 2 is fixed to the frame 4 with bolts or the like.

  The basic elements of the drive unit that drives the orbiting scroll 3 to rotate are the stator 5 and the rotor 6 that constitute the induction motor, the rotating shaft 7, the Oldham ring 8 that is a main part of the rotation preventing mechanism of the orbiting scroll 3, and the frame 4. A rotary shaft main shaft support portion 9 that rotatably engages the rotary shaft 7, and the orbiting scroll 3 and the eccentric portion of the rotary shaft 7 are movable in the direction of the rotary shaft and rotatably engaged. This is the shaft support portion 3c.

  The frame 4 incorporates a main shaft support portion 9. The stator 5 is fixed to the sealed container 1 by shrink fitting or the like. The rotor 6 is rotatably disposed within the annular stator 5. The rotating shaft 7 is rotatably supported by the main shaft support portion 9, and an intermediate portion of the rotating shaft 7 passes through the center portion of the rotor 6. The rotary shaft 7 is provided with an oil supply hole 10 penetrating the both end surfaces in the shaft center portion, and balances to cancel out the unbalanced force caused by the movement of the orbiting scroll 3 and keep the vibration of the compressor low. A balance weight 11 as a part is engaged.

  The Oldham ring 8 is disposed in the outer peripheral space 12 constituted by the frame 4 and the fixed scroll 2 together with the orbiting scroll 3, and one set of two orthogonal key portions formed on the Oldham ring 8 is attached to the frame 4. The remaining one set of the configured keyway slides on the keyway formed on the back side of the orbiting scroll wrap 3a.

  Next, the operation of the basic element described above will be described. The rotor 6 is given a rotational force by a rotating magnetic field generated by the stator 5, and the rotating shaft 7 fixed to the rotor 6 performs a rotating operation as the rotor 6 rotates. The orbiting scroll 3 is movably engaged with the eccentric portion of the rotating shaft 7 so as to be movable in the direction of the rotating shaft, and the rotating motion of the rotating shaft 7 is caused by the rotation preventing mechanism such as the Oldham ring 8 to rotate. Converted to. The volume of the compression chamber 14 formed by meshing the fixed scroll 2 and the orbiting scroll 3 decreases as the orbiting scroll 3 orbits. In the compression operation, the working fluid is sucked into the compression chamber 14 via the suction pipe 15 and the suction port 2c as the orbiting scroll 3 turns. The sucked working fluid communicates with the discharge port 2d through the compression stroke in the compression chamber 14, and is discharged through the discharge space 16 and the discharge pipe 17.

  Lubricating oil 13 accumulated in the lower space of the sealed container 1 passes through an oil supply hole 10 provided in the shaft center portion of the rotating shaft 7 and uses an oil pump 21 at the lower portion of the rotating shaft to compress the shaft and the shaft support portion 3c, 9, most of the lubricating oil 13 passes through the oil drain pipe 20 and is returned to the lower space of the sealed container 1. Instead of the oil pump 21 at the lower part of the rotating shaft, a centrifugal pump by an eccentric rotation operation of the oil hole 10 may be used.

  Between the shaft support portion end surface 3d of the orbiting scroll 3 and the frame 4 facing the end surface, a seal member 18 that holds the ring-shaped groove of the frame 4 is provided. The seal member 18 has a central space 19 having an opening in the oil supply passage at the center thereof, which has a pressure substantially equal to the discharge pressure and through which the lubricating oil 13 stored at the bottom of the sealed container 1 is guided upward. The outer peripheral space 12 is divided into the outer peripheral space 12 which is maintained at an intermediate pressure between the suction pressure and the discharge pressure. A force corresponding to a pressure difference between the central space 19 and the outer peripheral space 12 is applied to the seal member 18 from the lower side to the upper side, so that the gap between the upper end surface of the seal member 18 and the shaft support portion end surface 3d of the orbiting scroll 3 is increased. In addition to sealing, a force corresponding to the pressure difference is applied from the inside to the outside to seal between the outer peripheral side of the seal member 18 and the outer peripheral surface of the ring-shaped groove of the frame 4. Thereby, the shaft support portion 3c and the main shaft support of the orbiting scroll 3 are mixed without mixing most of the lubricating oil 13 supplied from the oil supply hole 10 of the rotary shaft 7 into the central space 19 with the compressed gas in the sealed container. The portion 9 is lubricated and returned to the inner bottom portion of the sealed container 1 via the oil drain pipe 20.

  The central space 19, the shaft support portion 3 c of the orbiting scroll 3, and the oil drain pipe 20 are subjected to a pressure increase effect due to the pump action and a pressure reduction effect due to the passage through the shaft support portions 3 c and 9 and the gap portion, but approximately the discharge pressure level. It is a pressure space.

  Here, an oil drain pipe 20 that is a pipe constituting a part of the oil supply path is drawn out of the sealed container 1 so as to exchange heat with the outside air. The oil draining pipe 20 is constituted by a meandering pipe having good heat conduction such as copper or aluminum so as to exchange heat with the outside air. With such a configuration, the lubricating oil 13 heated inside the compressor that becomes a high temperature during the operation of the compressor can be cooled by exchanging heat with the outside air temperature outside the compressor. The cooled lubricating oil 13 circulates in the compressor to cool the inside of the compressor, in particular, to absorb the heat generated by the motor, maintain the motor efficiency at a high efficiency, and improve the performance of the compressor. Reliability can be improved by absorbing heat generated by the shaft support portions 3c and 9 and the sliding portion. In the present embodiment, the oil drain pipe 20 that constitutes a part of the oil supply path after lubricating the shaft support portions 3c and 9 is provided so as to be drawn out of the sealed container 1 and to exchange heat with the outside air. The raised lubricating oil can be cooled with the outside air, and the cooling performance can be remarkably improved as compared with the case where the lubricating oil stored in the sealed container is cooled with the outside air.

In addition, as described as a conventional problem, the working fluid is dissolved in the lubricating oil stored in the sealed container during the stop, and the melted working fluid is heated by the heat generated by the electric motor or the like at the time of start-up to evaporate, The inside of the compressor becomes lower than the outside air temperature. In the present embodiment, the low-temperature lubricating oil 13 is heated by exchanging heat with the outside air outside the compressor, thereby promoting the temperature rise inside the compressor and speeding up the start-up of the air conditioner or the refrigerator. Can do. Moreover, by heating the lubricating oil and reducing its viscosity, it is possible to reduce the stirring loss of the shaft support portion and the sliding portion, and to prevent the shaft support portion and the sliding portion from being damaged.
(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 2 is a longitudinal sectional view of a positive displacement compressor according to a second embodiment of the present invention. The second embodiment is different from the first embodiment in the points described below, and the other points are basically the same as those in the first embodiment, so that the duplicate description is omitted.

  In the present embodiment, a fan 21 is installed in the vicinity of the oil drain pipe 20 drawn out of the sealed container 1, and the oil drain pipe 20 is forced to exchange heat with the outside air, thereby more actively promoting cooling of the lubricating oil. It is what you do. With this configuration, the lubricating oil 13 can be further cooled, and the motor efficiency and reliability can be further improved.

The heat source side heat exchanger of the refrigeration cycle in which the positive displacement compressor is used is used as a fan for forcibly exchanging heat with the outside of the pipe drawn out of the sealed container. Also good. In that case, it is possible to further improve the efficiency and reliability of the motor while suppressing an increase in equipment cost and equipment space.
(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 3 is a longitudinal sectional view of a positive displacement compressor according to a third embodiment of the present invention. The third embodiment is different from the first embodiment in the following points, and the other points are basically the same as those in the first embodiment, and thus redundant description is omitted.

  In the present embodiment, a heater 22 that heats the drain oil pipe 20 drawn out of the hermetic container 1 only at the time of start-up is provided, and heating of the lubricating oil at the time of start-up is more actively promoted. With such a configuration, the start-up of the air conditioner or the refrigerator can be more effectively accelerated by heating the lubricating oil 13 more quickly and further by heating to the outside air temperature or higher.

  Note that the present invention is not limited to the form disclosed in the above-described embodiment, but allows modifications based on known techniques.

It is a longitudinal section showing a positive displacement compressor of a 1st embodiment of the present invention. It is a longitudinal cross-sectional view of the positive displacement compressor of 2nd Embodiment of this invention. It is a longitudinal cross-sectional view of the positive displacement compressor of 3rd Embodiment of this invention. It is a longitudinal cross-sectional view which shows the conventional positive displacement compressor.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Sealed container, 2 ... Fixed scroll, 2a ... Fixed scroll wrap, 2b ... End plate, 2c ... Suction port, 2d ... Discharge port, 3 ... Turning scroll, 3a ... Wrap, 3b ... End plate, 3c ... Shaft support part, 3d ... End surface of the shaft support portion, 4 ... Frame, 5 ... Stator, 6 ... Rotor, 7 ... Rotating shaft, 8 ... Oldham ring, 9 ... Main shaft support portion, 10 ... Oil supply hole, 11 ... Balance weight, 12 ... Outer space , 13 ... Lubricating oil, 14 ... Compression chamber, 15 ... Suction pipe, 16 ... Discharge space, 17 ... Discharge pipe, 18 ... Seal member, 19 ... Central space, 20 ... Oil discharge pipe, 21 ... Oil supply pump, 22 ... Cooling fan, 23 ... heater.

Claims (5)

A compression unit and a drive unit that drives the compression unit are housed in a sealed container,
In the positive displacement compressor having an oil supply path for forcibly circulating the lubricating oil stored in the sealed container through the shaft support,
A positive displacement compressor characterized in that a pipe constituting a part of the oil supply path is provided so as to be drawn out of the hermetic container to exchange heat with outside air.   2. The positive displacement compressor according to claim 1, wherein a pipe constituting a part of the oil supply path after the shaft support portion is lubricated is drawn out of the hermetic container to exchange heat with outside air. The positive displacement compressor.   3. The positive displacement compressor according to claim 1, further comprising a fan for forcibly exchanging heat between the pipe drawn out of the sealed container and outside air.   4. The positive displacement compressor according to claim 3, wherein a heat source side fan for exchanging heat with the outside air of a heat source side heat exchanger of a refrigeration cycle in which the positive displacement compressor is used, and a pipe led out of the hermetic container are outside air. A positive displacement compressor characterized by being used as a fan for forcibly exchanging heat. 5. The positive displacement compressor according to claim 1, further comprising a heater that heats a pipe drawn out of the hermetic container only at the time of start-up.

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