JP4797548B2 - Hermetic electric compressor - Google Patents

Description

  The present invention relates to a hermetic electric compressor used in a refrigeration cycle.

In order to use a sliding bearing that is less expensive than a rolling bearing in a bearing portion that is configured in the hermetic electric compressor, a stable oil supply is required. In addition, there is a technology for supplying oil to the sliding bearing portion by constituting a positive displacement oil pump. Patent Document 2 described below describes a configuration in which an oil pump is disposed in either the middle housing or the orbiting scroll and oil is supplied to the main bearing and the orbiting bearing.
JP 2002-98055 A Japanese Patent No. 3045961

  However, in the configuration of Patent Document 1, a long through hole is formed in the shaft in order to supply the oil to the bearing portion from an oil sump arranged below the compression mechanism portion and the motor portion below. Must-have. For this reason, the processing cost of the shaft increases and the rigidity decreases. Furthermore, there is a problem that lubrication delay occurs in the early stage of starting because the oil must be lifted high, and a problem that power consumption of the oil pump increases.

  Further, the configuration of Patent Document 2 is a high-pressure dome type in which the electric motor part is on the high-pressure side, and the oil sump is also arranged on the high-pressure side, so that there is a problem that the entire outer housing becomes thick and increases in weight.

  The present invention has been made in view of the above-mentioned problems of the prior art, and its purpose is to construct an oil supply mechanism with a simple structure when the bearing portion is composed of a small and inexpensive sliding bearing. It is an object of the present invention to provide a hermetic electric compressor capable of obtaining reliable sliding.

In order to achieve the above object, the present invention employs technical means described in claims 1 to 5. That is, in the invention according to claim 1, an electric motor part (M) that rotationally drives the main shaft (21),
When the movable member (32) connected to the main shaft (21) is operated, the compression mechanism (C) that compresses the refrigerant sucked into the compression chamber (39) through the compression chamber suction path is connected to the sealed container (10 )
The motor part (M) is a low-pressure dome type placed in a low-pressure refrigerant atmosphere before compression,
The compression mechanism part (C) is disposed below the electric motor part (M),
The compression mechanism section (C) has bearing mechanisms (51 to 54) that assist the rotation of the main shaft (21) and the operation of the movable member (32).
The bearing mechanism (51-54) is slid by the lubricating oil,
The compression mechanism part (C) is an oil storage part (55) in a low-pressure refrigerant atmosphere provided at the upper part of the compression mechanism part for storing lubricating oil;
A refrigerant passage (57) that communicates with the compression chamber suction passage and through which the refrigerant sucked into the compression chamber (39) through the compression chamber suction passage passes ;
And a oil feed mechanism (60) to be fed between the bearing mechanism sucks the lubricating oil stored in the oil reservoir (55) (51, 53, 54),
The lubricating oil that has lubricated the bearing mechanism (54) is mixed with the refrigerant that has passed through the refrigerant passage (57) in the compression chamber suction passage, and is sucked into the compression chamber (39) and discharged to the outside .

  According to the first aspect of the present invention, the bearing mechanism (51 to 54) and the oil feeding mechanism (60) for feeding oil to the bearing mechanism can be arranged on the low pressure side. Since the low pressure side is the suction atmosphere temperature, it is possible to prevent the deterioration of the oil in the high temperature atmosphere and the decrease in the refrigerant flow rate caused by the high temperature oil mixed with the suction refrigerant and heating the refrigerant. And since it can supply lubricating oil stably with a simple oil feeding mechanism (60), even if it comprises a sliding bearing, reliable sliding can be obtained.

  Moreover, since it is a low-pressure dome type | mold, it is not necessary to thicken the thickness of the airtight container (10), and it can comprise lightweight. Furthermore, by arranging the oil reservoir (55) at the upper part of the compression mechanism, the lubricating oil can be supplied to the oil feeding mechanism (60) by its own weight drop, and each bearing can be promptly produced without delay even at the time of start-up. The mechanism (51, 53, 54) can be supplied. Moreover, the lubricating oil supply path (31c) can also be formed simply.

  The invention according to claim 2 is characterized in that, in the hermetic electric compressor according to claim 1, a positive displacement oil pump (60) is used as the oil feeding mechanism (60). According to the second aspect of the present invention, by using the positive displacement oil pump (60), the oil can be stably supplied from the low rotation to the high rotation.

  In the invention according to claim 3, in the hermetic electric compressor according to claim 1 or 2, the oil feeding mechanism (60) is driven by the main shaft (21). According to the third aspect of the present invention, a simple structure can be obtained by configuring the main shaft (21) without providing a separate drive mechanism.

  According to a fourth aspect of the present invention, in the hermetic electric compressor according to any one of the first to third aspects, the main shaft (21) is supported by a plurality of bearing mechanisms (51, 52). It is characterized by being. In the structure shown in Patent Document 2 of the above-described prior art, the main shaft is supported by a substantially central main bearing. According to the invention described in claim 4, the main shaft (21) is provided with a plurality of bearing mechanisms (51, 52), the inclination of the main shaft (21) can be suppressed. As a result, it is possible to suppress the contact of the main shaft (21) with respect to the sliding bearings (51, 52) and the increase in contact surface pressure, and it is possible to form a good oil film and obtain a reliable sliding.

According to a fifth aspect of the present invention, in the hermetic electric compressor according to any one of the first to fourth aspects, a carbon dioxide (CO ₂ ) refrigerant is used as the refrigerant. It is said. According to the fifth aspect of the present invention, when the carbon dioxide (CO ₂ ) refrigerant is used, the operating pressure is high and the load is large, so that the structure of the present invention is particularly effective. Incidentally, the reference numerals in parentheses of the above means are examples showing the correspondence with the specific means described in the embodiments described later.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a longitudinal sectional view of a hermetic electric compressor (hereinafter abbreviated as a compressor) 100 according to an embodiment of the present invention. This is an example applied to refrigerant compression in a refrigeration cycle, and other components of the refrigeration cycle are schematically shown in FIG.

  200 is a heat radiator for radiating heat from the high-temperature and high-pressure refrigerant discharged from the compressor 100, 300 is a decompressor for decompressing the refrigerant flowing out of the radiator 200, and 400 is for evaporating the refrigerant decompressed by the decompressor 300. A heat absorber 500 that absorbs heat and 500 is an accumulator that stores excess refrigerant.

  Next, the structure of the compressor 100 will be described. The compressor 100 includes an outer housing 10 as a sealed container, a compression mechanism portion C accommodated in the outer housing 10, and an electric motor portion M. The compressor 100 is arranged in the order of the compression mechanism part C and the electric motor part M in an upward direction from an installation surface (not shown) on the top and bottom side. For this reason, the compression mechanism C is disposed below the electric motor M. The electric motor part M is an electric compressor in which the compression mechanism part C is driven.

  Lubricating oil is supplied into the compressor 100 in order to appropriately slide bearings 51 to 54 (described later) used in the compressor. Such a compressor is a vertical scroll compressor that sucks lubricating oil together with low-pressure refrigerant from the upper part of the outer housing 10 and causes the low-pressure refrigerant and lubricating oil to flow down in the outer housing 10. According to this configuration, the lubricating oil is not stored in the outer housing 10 but is circulated in the refrigeration cycle together with the refrigerant.

  The lubricating oil sucked into the outer housing 10 flows down from the electric motor part M for driving the compression mechanism part C to the compression mechanism part C, lubricates the bearings 51 to 54 in the compressor, and then compresses the lubricating oil. The low-pressure dome type is discharged from the outer housing 10 together with the high-pressure refrigerant compressed by the mechanism C. According to this configuration, the supply of the lubricating oil to the bearings 51 to 54 can be realized with a simple configuration, and the lubricating oil sucked together with the low-pressure refrigerant is at a low temperature, so that the refrigerant can be efficiently compressed.

  The outer housing 10 includes a cylindrical main body casing 11, an upper casing 12, and a lower casing 13. These casings 11 to 13 are fixed, and a sealed space is formed in the outer housing 10. A leg portion 14 for vertically placing the compressor 100 is fixed to a lower portion of the outer peripheral surface of the main casing 11.

  A suction pipe 15 is provided in the upper casing 12. A low-pressure refrigerant for the refrigeration cycle and low-temperature lubricating oil (hereinafter referred to as oil) for sliding the bearings 51 to 54 flow into the outer housing 10 from the suction pipe 15.

  The electric motor unit M is composed of a rotor 22 fixed to a shaft 21 as a main shaft and a stator 23 on the outer peripheral side of the rotor 22. The stator 23 is fixed to the inner peripheral surface of the main casing 11 by shrink fitting or press fitting. Electric power is supplied to the motor unit M from an external power source (not shown) via the wiring 24, whereby the rotor 22 is driven to rotate, and the shaft 21 is also driven to rotate. .

  The compression mechanism C includes a center housing 31, a turning scroll member 32 as a movable member, a fixed scroll member 33, and a lower housing 34. The center housing 31 is fixed to the inner peripheral surface of the main body casing 11 by shrink fitting or press fitting.

  A main bearing installation portion 31a is formed in the center portion of the center housing 31 on the electric motor part M side, and a first sliding bearing 51 as a bearing mechanism is fixed to the main bearing installation portion 31a. On the other hand, a holder 25 having a secondary bearing installation portion 25a is provided on the upper portion of the main body casing 11, and a second sliding bearing 52 as a bearing mechanism is fixed to the secondary bearing installation portion 25a.

  The shaft 21 is rotatably supported by a first sliding bearing 51 on the center housing 31 side and a second sliding bearing 52 on the holder 25 side. An oil storage chamber 36 is formed in the center housing 31. On the other hand, a drive pin portion 21 a is integrally formed at the lower end portion of the shaft 21, and the drive pin portion 21 a is formed eccentrically with respect to the axis of the shaft 21.

  A balancer 37 for canceling dynamic imbalance during rotational driving is fixed to the shaft 21, and the balancer 37 rotates together with the shaft 21. The balancer 37 corresponds to an unbalance canceling member.

  An orbiting scroll member 32 is provided below the center housing 31. The orbiting scroll member 32 includes a substantially disc-shaped end plate portion 32a, a spiral blade portion 32b, and a substantially cylindrical boss portion 32c. The blade portion 32b is on the lower surface side of the end plate portion 32a. The boss part 32c is integrally formed on the upper surface side of the end plate part 32a.

  The drive pin portion 21a is inserted into the boss portion 32c via a swing sliding bearing 53 as a bearing mechanism. The orbiting scroll member 32 is connected to the shaft 21 by inserting the drive pin portion 21a into the boss portion 32c. By this orbiting sliding bearing 53, the rotational force of the shaft 21 is smoothly transmitted to the orbiting motion of the orbiting scroll member 32.

  The boss portion 32 c of the orbiting scroll member 32 also performs an orbiting motion in the oil storage chamber 36 of the center housing 31. The balancer 37 fixed to the shaft 21 rotates with its center of gravity biased so as to face the eccentricity of the drive pin portion 21a.

  In addition, a thrust slide bearing 54 as a bearing mechanism is provided between the center housing 31 and the outer peripheral portion of the end plate portion 32 a of the orbiting scroll member 32. The thrust sliding bearing 54 functions as a bearing when two superimposed donut-shaped thrust plates (thrust sliding members) 54a slide relative to each other. The upper thrust plate 54a is fixed to the center housing 31 by a joining pin (not shown), and the lower thrust plate 54a is fixed to the end plate portion 32a of the orbiting scroll member 32 by a joining pin (not shown).

  The thrust sliding bearing 54 serves to receive an axial reaction force applied to the orbiting scroll member 32 based on the compression of the refrigerant between the orbiting scroll member 32 and the fixed scroll member 33, that is, a thrust load. In addition, the thrust sliding bearing 54 allows the center housing 31 to support the orbiting scroll member 32 that performs the orbiting motion while being fixed to the outer housing 10.

  In the present embodiment, the first sliding bearing 51, the orbiting sliding bearing 53, and the thrust sliding bearing 54 described above are provided in the compression mechanism C, and the bearing mechanism assists the rotation of the shaft 21 and the operation of the orbiting scroll member 32. Equivalent to. Moreover, in this embodiment, each bearing 51-54 is comprised with the sliding bearing smaller and cheaper than a rolling bearing. An oil supply mechanism for these sliding bearings 51 to 54 is a main part of the present invention, and a detailed description thereof will be described later.

  A fixed scroll member 33 is disposed below the orbiting scroll member 32 to face the orbiting scroll member 32. The fixed scroll member 33 is fixed to the center housing 31 by a bolt 38A. A spiral blade portion 33 a is formed on the upper surface side of the fixed scroll member 33, and a substantially crescent-shaped compression chamber 39 is formed by fitting with the blade portion 32 b of the orbiting scroll member 32.

  That is, the blade portions 32b of the orbiting scroll member 32 mesh with the blade portions 33a of the fixed scroll member 33 while shifting their angles, and the blades of the scroll members 32 and 33 are formed so as to form a closed compression chamber 39 therebetween. The parts 32b and 33a are overlapped. The fixed scroll member 33 is provided with a compression chamber suction passage (not shown) that guides the refrigerant flowing down from the center housing 31 side to the compression chamber 39.

  The compression chamber suction passage guides the refrigerant from the outer peripheral sides of the scroll members 32 and 33 to the compression chamber 39. A discharge port 33 b for discharging the compressed refrigerant from the compression chamber 39 is formed in the center of the fixed scroll member 33. A lower housing 34 is provided below the fixed scroll member 33. The lower housing 34 is fixed to the fixed scroll member 33 by a port 38B.

  A discharge chamber 40 is formed by being recessed in the fixed scroll member 33 and the lower housing 34, and the discharge chamber 40 communicates with the compression chamber 39 through the discharge port 33b. A reed valve 41 is provided in the discharge chamber 40. The reed valve 41 is configured to open toward the discharge chamber 40 and is a valve that prevents the high-pressure refrigerant in the discharge chamber 40 from flowing back into the compression chamber 39.

  Further, the fixed scroll member 33 is formed with a discharge passage 33c for discharging the high-pressure refrigerant in the discharge chamber 40 to the outside. And the discharge pipe 42 is provided in the lower part of the main body casing 11, The high pressure refrigerant | coolant which passed the discharge channel | path 33c from this discharge pipe 42 flows into a refrigerating cycle.

  Next, a characteristic configuration of the present embodiment will be described. As shown in FIG. 1, the motor part M side (upper side) of the center housing 31 is formed so as to protrude from the outer peripheral side toward the center part. The center housing 31 has an oil reservoir 55 formed therein.

  The oil reservoir 55 is formed from the surface on the motor part M side (upper side) of the center housing 31 and the inner peripheral surface of the main body casing 11, and temporarily receives the lubricating oil flowing from the suction pipe 15 and flowing down from the motor part M side. It has come to be stored. A refrigerant suction pipe 56 projects from the oil storage part 55 of the center housing 31.

  A communication hole 31 b is formed in the center housing 31 so as to correspond to the refrigerant suction pipe 56, and the refrigerant passage is formed by the pipe of the refrigerant suction pipe 56 and the communication hole 31 b formed in the center housing 31. 57 is configured. An inlet end portion 56 a of the refrigerant passage 57 is formed so as to protrude from the oil storage portion 55 to the electric motor portion M side by the refrigerant suction pipe 56. The refrigerant passage 57 is formed so as to communicate with the compression chamber suction passage (not shown).

  The refrigerant suction pipe 56 (refrigerant passage 57) is provided away from the inner peripheral surface of the main body casing 11 (outer housing 10). On the other hand, an oil suction passage 31c extending obliquely downward from the outer peripheral side toward the center side is formed at the skirt portion of the portion of the center housing 31 that protrudes toward the motor part M side. The inlet end of the oil suction passage 31 c is formed to open near the bottom of the oil reservoir 55.

  Further, as shown in FIG. 1, a positive displacement oil pump 60 as an oil feeding mechanism is disposed on the top surface side (motor unit M side) portion in the oil storage chamber 36. 2 is a cross-sectional view taken along the line AA in FIG. 1, showing a rolling piston type as a structural example of the positive displacement oil pump 60 according to the present invention, and FIG. 3 is an operation explanatory view of the oil pump 60 in FIG. is there.

  A rotor 62 attached eccentrically to the shaft 21 is rotated by the shaft 21 in the central space of the pump housing 61, thereby forming a substantially crescent-shaped compression chamber formed between the inner surface of the pump housing 61 and the outer surface of the rotor 62. 63 is swiveled, and the operation is performed so that the oil taken into the compression chamber 63 at the suction port 64 is pressurized and discharged from the discharge port 65. The component 66 is a vane that always contacts the outer surface of the rotating rotor 62 and separates the suction side and the discharge side.

  The suction port 64 communicates with the oil suction passage 31c described above, and the discharge port 65 opens into the oil storage chamber 36. The oil in the oil storage portion 55 is taken in from the oil suction passage 31c and is stored in the oil storage chamber 36. The pumping operation is performed. The oil pumped into the oil storage chamber 36 is supplied to the sliding surface of the thrust sliding bearing 54 and at the same time, the sliding surface with the swivel sliding bearing 53 from the oil groove 21b provided on the outer surface of the drive pin portion 21a of the shaft 21. Also supplied.

  The oil supplied to the oil groove 21b rises upward through an oil supply hole 21c opened from the bottom surface at the center of the shaft 21 and reaches an oil groove 21d provided on the outer surface of the shaft 21. To the sliding surface with the first sliding bearing 51.

  Next, the operation of the compressor 100 configured as described above will be described. When electric power is supplied to the motor unit M from the outside, the rotor 22 is driven to rotate, and the shaft 21 rotates accordingly. As the shaft 21 rotates, the drive pin portion 21a also rotates, so that the orbiting scroll member 32 orbits (activates) around the shaft 21 with a predetermined amount of eccentricity.

  Next, the flow of refrigerant and oil accompanying the operation of the compressor 100 will be described. FIG. 4 is a schematic diagram for explaining the flow of oil in the hermetic electric compressor 100 of the present invention. First, due to the operation of the compressor 100, low-pressure refrigerant and low-temperature oil flow from the suction pipe 15 into the outer housing 10.

  In principle, the refrigerant flowing from the suction pipe 15 is a gas. Then, the refrigerant and oil flow down in the outer housing 10. At this time, since the suction pipe 15 is provided in the upper casing 12 of the outer housing 10, oil is supplied to the second sliding bearing 52 fixed to the holder 25 from above. As a result, the second sliding bearing 52 is lubricated.

  The refrigerant and oil that have passed through the gap in the electric motor part M flow down to the compression mechanism part C from the electric motor part M side. At this time, a centrifugal force is generated by the rotation of the rotor 22 and the shaft 21, and the oil having a higher specific gravity than the refrigerant is scattered in the centrifugal direction by the centrifugal force. As a result, the oil adheres to the inner peripheral surface of the main casing 11 while the gaseous refrigerant flows down without being affected by the centrifugal force.

  Then, the refrigerant is sucked from the inlet end portion 56a of the refrigerant suction pipe 56 (refrigerant passage 57), and is sucked into the compression chamber 39 through the refrigerant passage 57 and the compression chamber suction passage. Thereafter, the refrigerant is compressed in the compression chamber 39 to be a high-pressure refrigerant, and is discharged from the discharge pipe 42 through the discharge port 33b, the discharge chamber 40, and the discharge passage 33c.

  On the other hand, the oil adhering to the inner peripheral surface of the main body casing 11 due to the centrifugal force flows down to the oil storage portion 55 of the center housing 31 through the inner peripheral surface, and is temporarily stored in the oil storage portion 55. The oil stored in the oil storage part 55 is sucked into the oil pump 60 from the oil suction path 31 c opened in the oil storage part 55, and discharged from the oil pump 60 into the oil storage chamber 36.

  At this time, the inlet end portion 56 a of the refrigerant passage 57 is formed so as to protrude upward from the oil storage portion 55 (on the electric motor portion M side), whereas the inlet end portion of the oil suction path 31 c is the bottom portion of the oil storage portion 55. An opening is formed in the vicinity. For this reason, the oil temporarily stored in the oil storage part 55 can be reliably guided to the oil suction path 31 c without flowing into the refrigerant passage 57.

  Further, the inlet end portion 56 a of the refrigerant passage 57 is provided to be separated from the inner peripheral surface of the main body casing 11. For this reason, even if the oil adhering to the inner peripheral surface of the main body casing 11 due to centrifugal force flows along the inner peripheral surface and flows down to the oil reservoir 55 of the center housing 31, the oil does not flow into the refrigerant passage 57. . Part of the oil stored in the oil storage chamber 36 enters a slight gap in the thrust slide bearing 54 that constitutes a part of the side surface of the oil storage chamber 36. The thrust sliding bearing 54 is lubricated by the oil that has entered from the oil storage chamber 36.

  As described above, since the thrust sliding bearing 54 slides with the two thrust plates 54a receiving the thrust load from the orbiting scroll member 32, the amount of oil entering the thrust sliding bearing 54 is as follows. The oil storage chamber 36 does not hinder oil storage. The oil that has finished lubricating the thrust sliding bearing 54 is mixed with the refrigerant and sucked from the compression chamber suction path to the compression chamber 39 to circulate.

  In addition, the other part of the oil stored in the oil storage chamber 36 is guided to the swing sliding bearing 53 through the oil groove 21 b provided on the outer surface of the drive pin portion 21 a of the shaft 21. As a result, the swivel slide bearing 53 is lubricated by the oil from the oil groove 21b. For this reason, oil can be reliably supplied from the oil storage chamber 36 to the swing sliding bearing 53 by the oil groove 21b.

  The oil supplied to the oil groove 21b rises upward through an oil supply hole 21c opened from the bottom surface of the shaft 21, reaches the oil groove 21d provided on the outer surface of the shaft 21, and from here 1 is guided to the sliding bearing 51. As a result, the first sliding bearing 51 is lubricated by the oil from the oil groove 21d.

  For this reason, oil can be reliably supplied from the oil storage chamber 36 to the first sliding bearing 51 by the oil groove 21b, the oil supply hole 21c, and the oil groove 21d. Then, the oil that has finished lubricating the swivel sliding bearing 53 and the first sliding bearing 51 springs out from the upper end surface of the first sliding bearing 51 and circulates back to the oil storage section 55.

  The oil that has overflowed from the oil reservoir 55 to the refrigerant passage 57 passes through the compression chamber suction passage together with the refrigerant, and is sucked into the compression chamber 39. Thereafter, it is compressed together with the refrigerant in the compression chamber 39 to become high-temperature oil, and is discharged from the discharge pipe 42 through the discharge port 33b, the discharge chamber 40, and the discharge passage 33c.

  In this way, the rotation of the shaft 21, the turning of the drive pin portion 21a and the boss portion 32c, and the thrust load applied to the turning scroll member 32 are all supported by the sliding bearings 51, 53, and 54. For this reason, for example, compared with the case where a rolling bearing is used, size reduction of a bearing part can be achieved.

  As described above, the refrigerant is reliably guided to the compression chamber suction passage by the refrigerant passage 57, while the oil is reliably guided to the oil storage chamber 36 from the oil suction passage 31c by the oil pump 60. Then, the thrust sliding bearing 54, the turning sliding bearing 53, the first sliding bearing 51, and the oil can be reliably guided from the oil storage chamber 36, and the bearings 51, 53, 54 in the compressor 100 can be reliably lubricated. it can.

  Even when sufficient oil is not supplied into the compressor 100 due to the transient fluctuation of the oil concentration, the oil flowing in from the suction pipe 15 and flowing down to the compression mechanism C side is surely stored in the oil storage chamber 36. Therefore, the bearings 51, 53, and 54 in the compressor 100 can be properly lubricated. As a result, the bearings 51, 53 and 54 do not run out of oil, and the reliability of the compressor 100 can be improved.

Next, features and effects of this embodiment will be described. First, the motor part M that rotates the shaft 21 and the orbiting scroll member 32 connected to the shaft 21 are operated to compress the refrigerant sucked into the compression chamber 39 through the compression chamber suction path. In the outer housing 10, the electric motor part M is a low-pressure dome type placed in a low-pressure refrigerant atmosphere before compression, the compression mechanism part C is disposed below the electric motor part M, and the compression mechanism part C is The bearings 51, 53, and 54 assist the rotation of the shaft 21 and the operation of the orbiting scroll member 32. The bearings 51, 53, and 54 are slid by the lubricating oil, and the compression mechanism C stores the lubricating oil. intake and the oil reservoir portion 55 communicates with the compression chamber suction passage, the refrigerant passage 57 which refrigerant passes to be drawn through the compression chamber intake passage into the compression chamber 39, the lubricating oil stored in the oil reservoir 55 of the To and a oil pump 60 to be fed between the bearing 51 · 53 · 54. The lubricating oil that has lubricated the thrust sliding bearing 54 is mixed with the refrigerant that has passed through the refrigerant passage 57 in the compression chamber suction passage, and is sucked into the compression chamber 39 and discharged to the outside.

  According to this, each bearing 51 * 53 * 54 and the oil pump 60 which supplies oil to it can be arrange | positioned at the low voltage | pressure side. Since the low pressure side is the suction atmosphere temperature, it is possible to prevent the deterioration of the oil in the high temperature atmosphere and the decrease in the refrigerant flow rate caused by the high temperature oil mixed with the suction refrigerant and heating the refrigerant. And since it can supply lubricating oil stably with the simple oil pump 60, reliable sliding can be obtained even if it comprises a sliding bearing.

  Further, since it is a low-pressure dome type, it is not necessary to increase the thickness of the outer housing 10, and it can be configured to be lightweight. Furthermore, by arranging the oil storage part 55 at the upper part of the compression mechanism part, the lubricating oil can be supplied to the oil feeding mechanism 60 due to its own weight drop, and each bearing 51, 53. 54. Moreover, the lubricating oil supply path 31c can also be formed simply.

  A positive displacement oil pump 60 is used as the oil feeding mechanism 60. According to this, by using the positive displacement oil pump 60, it is possible to stably supply oil from a low rotation to a high rotation. The oil pump 60 is driven by the shaft 21. According to this, it can be set as a simple structure by comprising in the shaft 21 without providing a drive mechanism separately.

  The shaft 21 is supported by a plurality of bearings 51 and 52. In the structure shown in Patent Document 2 of the above-described prior art, the main shaft is supported by a substantially central main bearing. However, according to this, the shaft 21 is supported by a plurality of bearings 51 and 52 so that the inclination of the shaft 21 is increased. Can be suppressed. As a result, the contact of the shaft 21 with respect to the sliding bearings 51 and 52 and an increase in contact surface pressure can be suppressed, and an excellent oil film can be formed to obtain a reliable sliding.

Further, carbon dioxide (CO ₂ ) refrigerant is used as the refrigerant. According to this, when the carbon dioxide (CO ₂ ) refrigerant is used, the operating pressure is high and the load is also large, so that the structure of the present invention is particularly effective.

(Other embodiments)
The present invention is not limited to the above-described embodiments, and can be modified or expanded as follows. In the above-described embodiment, the scroll compression mechanism is employed as the compression mechanism C. However, the hermetic electric compressor according to the present invention may be other compression mechanisms such as a vane type and a rotasco (rolling piston) type.

  Further, the motor 30 is a DC brushless motor, but may be another electric motor such as an induction motor. Moreover, although the rolling piston type is shown as the positive displacement oil pump 60, it may be a trochoid type, a vane type, a gear type, or the like.

1 is a longitudinal sectional view of a hermetic electric compressor 100 according to an embodiment of the present invention. It is AA sectional drawing in FIG. 1, and shows the structural example of the positive displacement oil pump 60 concerning this invention. FIG. 3 is an operation explanatory diagram of the oil pump 60 of FIG. 2. It is a schematic diagram explaining the flow of the oil in the hermetic electric compressor 100 of the present invention.

Explanation of symbols

10 ... Outer housing (sealed container)
21 ... Shaft (main shaft)
31c ... Lubricating oil supply path 32 ... Revolving scroll member (movable member)
36 ... Oil storage chamber 39 ... Compression chamber 51 ... First sliding bearing (bearing mechanism)
52. Second sliding bearing (bearing mechanism)
53 ... Swivel sliding bearing (bearing mechanism)
54. Thrust sliding bearing (bearing mechanism)
55 ... Oil reservoir 56a ... Inlet end of refrigerant passage 57 ... Refrigerant passage 60 ... Positive displacement oil pump (oil feeding mechanism)
C: Compression mechanism CO ₂ ... Carbon dioxide M ... Electric motor

Claims (5)

An electric motor unit (M) for rotationally driving the main shaft (21);
When the movable member (32) connected to the main shaft (21) is operated, the compression mechanism (C) that compresses the refrigerant sucked into the compression chamber (39) through the compression chamber suction passage is sealed with a sealed container ( 10)
The electric motor part (M) is a low-pressure dome type placed in a low-pressure refrigerant atmosphere before compression,
The compression mechanism portion (C) is disposed below the electric motor portion (M),
The compression mechanism (C) has bearing mechanisms (51 to 54) that assist the rotation of the main shaft (21) and the operation of the movable member (32),
The bearing mechanism (51-54) is slid by lubricating oil,
The compression mechanism (C) is an oil reservoir of the low-pressure refrigerant atmosphere provided in the compression mechanism unit top for storing lubricating oil (55),
A refrigerant passage (57) that communicates with the compression chamber suction passage and through which the refrigerant sucked into the compression chamber (39) through the compression chamber suction passage passes ;
And a oil feed mechanism (60) to be fed between the bearing mechanism to suck the lubricating oil stored in the oil reservoir (55) (51, 53, 54),
The lubricating oil that has lubricated the bearing mechanism (54) is mixed with the refrigerant that has passed through the refrigerant passage (57) in the compression chamber suction passage, and is sucked into the compression chamber (39) and discharged to the outside. Hermetic type electric compressor characterized by   The hermetic electric compressor according to claim 1, wherein a positive displacement oil pump (60) is used as the oil feeding mechanism (60).   The hermetic electric compressor according to claim 1 or 2, wherein the oil feeding mechanism (60) is driven by the main shaft (21).   The hermetic electric compressor according to any one of claims 1 to 3, wherein the main shaft (21) is supported by a plurality of the bearing mechanisms (51, 52). 5. The hermetic electric compressor according to claim 1, wherein a carbon dioxide (CO ₂ ) refrigerant is used as the refrigerant.

Images