JP2013241883A - Compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compressor capable of mixing refrigerant and lubricating oil as much as possible with a simple structure even in situations in which the refrigerant and the lubricating oil are likely to be separated.SOLUTION: A compressor comprises: a compression mechanism 15 compressing refrigerant; a drive motor 16 driving the compression mechanism; a hollow shaft 70 connected to the compression mechanism 15 and the drive motor 16, transmitting drive force of the drive motor 16 to the compression mechanism 15, and formed with an oil supply hole 61 extending in an axial direction; and a casing 10 in which an oil storage space P storing lubricating oil is formed at a bottom part of an internal space thereof, for immersing a lower end of the shaft into the lubricating oil. In the shaft 70, an expanding part 71 is formed in a lower end proximity part of a lower end thereof. The expanding part is formed so that it expands from a lower end of a main shaft part except the expanding part and that an outer surface is inclined relative to a central axis O-O of the drive motor 16.

Description

  The present invention relates to a compressor.

  Conventionally, as disclosed in Patent Document 1 (Japanese Patent Application Laid-Open No. 2010-285930), a compression mechanism that compresses refrigerant, a drive motor that drives the compression mechanism, and a drive of the drive motor that is connected to the compression mechanism and the drive motor. There is a compressor including a drive shaft that transmits a force to a compression mechanism. In such a compressor, an oil storage space for storing lubricating oil for improving the lubricity of the sliding portion including the sliding portion of the compression mechanism is formed in the compressor.

  In such a compressor, as described in Patent Document 1, a part of the drive shaft is immersed in the oil storage space in order to supply lubricating oil in the oil storage space to the sliding portion. The drive shaft is formed with an oil supply hole for guiding lubricating oil to the sliding portion.

  In the compressor as described above, depending on the pressure state and the temperature state, it is considered that the refrigerant and the lubricating oil are separated in the oil storage space. And if it isolate | separates so that a refrigerant | coolant may be located under lubricating oil, there will be a concern that a lot of refrigerant flows in an oil supply hole and lubricating oil does not flow so much. For this reason, there is a concern that poor lubrication may occur in the sliding portion. In particular, there is a concern that this tendency becomes remarkable when a refrigerant that is easily separated from the lubricating oil is used.

  Accordingly, an object of the present invention is to provide a compressor capable of mixing refrigerant and lubricating oil as much as possible even in a situation where the refrigerant and lubricating oil are easily separated.

  A compressor according to a first aspect of the present invention includes a compression mechanism that compresses a refrigerant, a drive motor that drives the compression mechanism, a hollow shaft, and a casing. The shaft is connected to a compression mechanism and a drive motor, and transmits a driving force of the drive motor to the compression mechanism, and has a hole extending in the axial direction. The casing accommodates the compression mechanism, the drive motor, and the shaft, and an oil storage space is formed at the bottom of the internal space in which the lubricating oil is stored and the lower end of the shaft is immersed in the lubricating oil. The shaft has an enlarged portion in the vicinity of the lower end of the lower end. The enlarging part is a part formed so as to expand radially outward from the lower end of the main shaft part excluding the enlarging part and so that the outer surface is inclined with respect to the central axis of the drive motor.

  Here, when the shaft is axially rotated, in the lubricating oil (specifically, lubricating oil and refrigerant) stored in the oil storage space, a rotating flow that rotates along the outer surface of the shaft is generated. In the present invention, an enlarged portion is formed on a part of the shaft (near the lower end) so as to expand radially outward from the lower end of the main shaft portion and the outer surface is inclined with respect to the central axis. The speed of the rotational flow of the lubricating oil (lubricating oil and refrigerant) generated around the outer surface along the outer surface of the portion can be changed in the axial direction. And since the pressure difference is produced in the axial direction due to the speed difference in the axial direction of the rotational flow of the lubricating oil (lubricating oil and refrigerant), the axial flow in the lubricating oil (lubricating oil and refrigerant) stored in the oil storage space Can be generated.

  Therefore, even if the refrigerant and the lubricating oil are separated in the oil storage space, they can be mixed. Thus, in the present invention, the refrigerant and the lubricating oil can be mixed as much as possible even in a situation where the refrigerant and the lubricating oil are easily separated with a simple structure.

  A compressor according to a second aspect of the present invention is the compressor according to the first aspect of the present invention, wherein the shaft is formed such that the outer diameter of the enlarged portion continuously changes in the axial direction. Yes.

  In the present invention, the rotational flow speed of the lubricating oil (lubricating oil and refrigerant) generated around the outer surface of the enlarged portion when the shaft is axially rotated is continuously changed in the axial direction. Can do. Therefore, even when the refrigerant and the lubricating oil are separated into two layers, they are easily mixed.

  A compressor according to a third aspect of the present invention is the compressor according to the first or second aspect of the present invention, wherein the shaft has a maximum outer diameter of the enlarged portion of 120 which is the outer diameter of the lower end of the main shaft portion. It is formed so that it may become more than%.

  In the present invention, it is possible to make the outer diameter in the axial direction of the enlarged portion different by making the enlarged portion have such a shape. Therefore, even if the refrigerant and the lubricating oil are separated into two layers, they can be mixed.

  A compressor according to a fourth aspect of the present invention is the compressor according to any one of the first aspect to the third aspect of the present invention, wherein the shaft has an enlarged portion that is symmetric about the central axis. Is formed.

  In the present invention, even if the shape of the vicinity of the lower end of the shaft is formed so as to extend radially outward from the lower end of the main shaft portion and the outer surface is inclined with respect to the central axis, it is symmetric about the central axis. Since it forms, it can suppress that a power loss increases.

  In the compressor which concerns on the 5th viewpoint of this invention, it is a compressor which concerns on either of the 1st viewpoint of this invention-4th viewpoint, Comprising: As for an expansion part, lubricating oil is most stored in the oil storage space. When the oil level in the case is used as a reference, it occupies more than half in the axial direction of the portion below the oil level of the shaft.

  In the present invention, in the shaft, the enlarged portion is a half in the axial direction of the portion below the oil level height when the oil level is a reference when the most lubricating oil is stored in the oil storage space. It accounts for the above. Therefore, even when the refrigerant and the lubricating oil are separated, they are easily mixed.

  The compressor according to the sixth aspect of the present invention is the compressor according to any one of the first to fourth aspects of the present invention, and further includes a lower bearing that pivotally supports the lower portion of the shaft. The enlarged portion occupies more than half in the axial direction of the portion below the portion supported by the lower bearing of the shaft.

  In the present invention, in the shaft, the enlarged portion occupies more than half of the portion in the axial direction below the portion that is pivotally supported by the lower bearing of the shaft. Therefore, even when the refrigerant and the lubricating oil are separated, they are easily mixed.

  The compressor according to the present invention is to provide a compressor capable of mixing refrigerant and lubricating oil as much as possible even in a situation where the refrigerant and lubricating oil are easily separated with a simple structure.

The longitudinal cross-sectional view of the scroll compressor which concerns on one Embodiment of the compressor which concerns on this invention. The enlarged schematic diagram of the II section of FIG. The schematic diagram which shows the expansion part periphery of the shaft which shows the other ratio with respect to the bearing lower part of an expansion part. The schematic diagram which shows the other shape of the lower end vicinity part of a shaft. The schematic diagram which shows the other shape of the lower end vicinity part of a shaft.

  Hereinafter, a scroll compressor 101 according to an embodiment of a compressor according to the present invention will be described with reference to the drawings.

(1) Configuration of Scroll Compressor 101 FIG. 1 is a longitudinal sectional view of the scroll compressor 101 according to the present embodiment. In the following description, a central axis O− passing through the center of the drive motor 16 shown in FIG. A direction along O is defined as an axial direction or a vertical direction.

  The scroll compressor 101 is used to compress a refrigerant in a refrigerant circuit that performs a refrigeration cycle by circulating the refrigerant. The scroll compressor 101 is a high- and low-pressure dome type compressor, and compresses the refrigerant by revolving at least one scroll of two scrolls meshing with each other without rotating. In the present embodiment, R32 refrigerant is used as the refrigerant.

  As shown in FIG. 1, the scroll compressor 101 includes a casing 10, a compression mechanism 15, a housing 23, an upper bearing 33, an Oldham coupling 39, a drive motor 16, a lower bearing 60, an oil separation plate. 65, a shaft 70, and a gas guide 58. The scroll compressor 101 includes a compression mechanism 15, a housing 23, an upper bearing 33, an Oldham joint 39, a drive motor 16, a lower bearing 60, an oil separation plate 65, a shaft 70, and a gas guide 58 in the internal space of the casing 10. It has an enclosed sealed structure.

  Hereinafter, components of the scroll compressor 101 will be described.

(1-1) Casing 10
The casing 10 is a vertical cylindrical container extending in the axial direction. The casing 10 mainly includes a substantially cylindrical tubular portion 11 and a bowl-shaped upper wall portion 12 welded to the upper end of the tubular portion 11 in an airtight manner. And a bowl-shaped bottom wall portion 13 which is welded to the lower end of the cylindrical portion 11 in an airtight manner.

  A suction pipe 19 and a discharge pipe 20 are welded to the casing 10 in an airtight manner. The suction pipe 19 is a tubular member that penetrates the upper wall portion 12, and is a member that introduces refrigerant that circulates in the refrigerant circuit from the outside of the casing 10 to the compression mechanism 15. The lower end of the suction pipe 19 is fitted in the fixed scroll 24. The discharge pipe 20 is a tubular member that penetrates the cylindrical portion 11, and is a member that discharges the compressed refrigerant from the high-pressure space S <b> 1 to the outside of the casing 10.

  An oil storage space P that is a space for storing lubricating oil is formed at the bottom of the internal space of the casing 10. Lubricating oil is used to keep the lubricity of sliding parts such as the compression mechanism 15 good during the operation of the scroll compressor 101.

(1-2) Compression mechanism 15
The compression mechanism 15 sucks the low-temperature and low-pressure refrigerant, and discharges it after compressing the low-temperature and low-pressure refrigerant into a high-temperature and high-pressure refrigerant. The compression mechanism 15 is connected to the upper end of the shaft 70. The compression mechanism 15 mainly has a fixed scroll 24 and a movable scroll 26.

(1-2-1) Fixed scroll 24
The fixed scroll 24 includes a disk-shaped first end plate 24a and a spiral (involute-shaped) first wrap 24b connected to the lower surface of the first end plate 24a and orthogonal to the lower surface of the first end plate 24a. ing.

  The fixed scroll 24 is formed with a main suction hole (not shown) and an auxiliary suction hole (not shown) adjacent to the main suction hole. The main suction hole is a hole that communicates the internal space of the suction pipe 19 and a compression chamber 40 described later. The auxiliary suction hole is a hole that communicates the low-pressure space S <b> 2 described later and the compression chamber 40.

  A discharge hole 41 is formed at the center of the first end plate 24a. The discharge hole 41 is a hole for discharging the refrigerant compressed in the compression chamber 40. In addition, an enlarged recess 42 communicating with the discharge hole 41 is formed on the upper surface of the first end plate 24a. The enlarged recess 42 is a space that is recessed in the upper surface of the first end plate 24a and extends in the horizontal direction. A lid 44 is fastened and fixed to the upper surface of the fixed scroll 24 by bolts 44 a so as to close the enlarged concave portion 42. And the muffler space 45 which consists of an expansion chamber which silences the driving | running sound of the compression mechanism 15 by covering the expansion recessed part 42 with the cover body 44 is formed. The fixed scroll 24 and the lid 44 are sealed by being brought into close contact with each other via a gasket (not shown). The fixed scroll 24 is formed with a first communication passage 46 that communicates with the muffler space 45 and opens on the lower surface of the fixed scroll 24.

(1-2-2) Movable scroll 26
The movable scroll 26 includes a second end plate 26a and a second wrap 26b having a spiral shape (involute shape) connected to the upper surface of the second end plate 26a and orthogonal to the upper surface of the second end plate 26a. An upper end bearing 26c serving as a bearing that pivotally supports the upper end portion 74 of the shaft 70 is formed at the center of the lower surface of the second end plate 26a. Oil supply pores 63 are formed in the second end plate 26a. The oil supply pore 63 communicates the outer peripheral portion of the upper surface of the second end plate 26a and the space inside the upper end bearing 26c.

  In the compression mechanism 15 having the above configuration, the first end plate 24a, the first end plate 24b, the second end plate 26a, and the second end plate 26a of the movable scroll 26 mesh with the first end plate 24b of the fixed scroll 24 and the second end plate 26a. A compression chamber 40, which is a space surrounded by the second wrap 26b, is formed. In the compression chamber 40, the refrigerant is compressed by reducing the volume by the revolving motion of the movable scroll 26.

(1-3) Housing 23
The housing 23 is disposed below the compression mechanism 15, and its outer peripheral surface is joined to the inner wall of the casing 10 in an airtight manner. The internal space of the casing 10 is partitioned by the housing 23 into a high-pressure space S1 below the housing 23 and a low-pressure space S2 above the housing 23.

  The housing 23 mounts the fixed scroll 24 by being fixed with a bolt or the like, and sandwiches the movable scroll 26 together with the fixed scroll 24 via an Oldham joint 39 described later. Further, a hole penetrating in the axial direction is formed in the outer peripheral portion of the housing 23, and this hole forms a second communication passage 48. The second communication passage 48 communicates with the first communication passage 46 and the high-pressure space S1.

  The housing 23 is formed with a housing through hole 31 that extends in the axial direction from the center of the upper surface of the housing 23 toward the center of the lower surface. An upper bearing 33 is fixed in close contact with a through hole forming surface 31 b that forms the housing through hole 31 of the housing 23. The upper end bearing 26 c described above is formed so as to be positioned in the housing through hole 31 and above the upper bearing 33.

(1-4) Upper bearing 33
The upper bearing 33 is a rolling bearing having an inner ring 33a, a plurality of rolling elements 33b, and an outer ring 33c. The inner ring 33 a is fixed in close contact with the outer peripheral surface of the shaft 70. The outer ring 33c is fixed in close contact with the through hole forming surface 31b. The rolling element 33b is fitted between the inner ring 33a and the outer ring 33c so as to roll freely. The rolling element 33b is, for example, a sphere or a roller. In this way, the upper bearing 33 pivotally supports the shaft 70 in a rotatable manner.

(1-5) Oldham coupling 39
The Oldham joint 39 is an annular member for preventing the movable scroll 26 from rotating. The Oldham coupling 39 is fitted into an oblong Oldham groove 26 d formed in the housing 23.

(1-6) Drive motor 16
The drive motor 16 is a brushless DC motor that is coupled to the shaft 70 and drives the compression mechanism 15 via the shaft 70. The drive motor 16 is disposed below the housing 23.

  The drive motor 16 mainly includes a stator 51 that is fixed to the inner wall of the cylindrical portion 11 of the casing 10 and a rotor 52 that is rotatably disposed inside the stator 51 in the radial direction. An air gap, which is a slight gap, is formed between the inner peripheral surface of the stator 51 and the outer peripheral surface of the rotor 52.

  The stator 51 has a coil part (not shown) around which a conducting wire is wound, and a coil end 53 formed above and below the coil part. In addition, a plurality of core cut portions (not shown) are formed on the outer peripheral surface of the stator 51 so as to extend from the upper end surface to the lower end surface of the stator 51 and at predetermined intervals in the circumferential direction. ing. The core cut portion forms a motor cooling passage 55 extending in the axial direction between the tubular portion 11 and the stator 51.

  A shaft 70 is fitted (connected) to the rotor 52. The shaft 70 is fitted into the rotor 52 so that the central axis of the portion excluding the upper end 74 passes through the rotation center of the rotor 52.

(1-7) Lower bearing 60
The lower bearing 60 is a bearing that is disposed below the drive motor 16 and supports the lower portion of the shaft 70. The outer surface of the lower bearing 60 is joined to the inner wall of the cylindrical portion 11 of the casing 10 in an airtight manner.

(1-8) Oil separation plate 65
The oil separation plate 65 is a flat plate-like member that separates the lubricating oil from the descending refrigerant. The oil separation plate 65 is fixed to the upper end surface of the lower bearing 60.

(1-9) Shaft 70
FIG. 2 is an enlarged schematic view of the II part of FIG.

  The shaft 70 has a hollow shape in which an oil supply hole 61 extending in the axial direction is formed. The oil supply hole 61 is formed to extend from the upper end surface to the lower end surface of the shaft 70. The lower end of the shaft 70 is immersed in the lubricating oil stored in the oil storage space P, and the oil supply hole 61 communicates with the oil storage space P. The oil supply hole 61 communicates with the oil chamber 83. The oil chamber 83 is a space formed by the upper end surface of the shaft 70 and the lower surface of the second end plate 26a. The oil chamber 83 communicates with a sliding portion (referred to as a sliding portion of the compression mechanism 15 in this embodiment as appropriate) between the fixed scroll 24 and the movable scroll 26 via an oil supply hole 63 of the second end plate 26a. ing. The oil chamber 83 communicates with the low pressure space S <b> 2 via the compression chamber 40.

  With the scroll compressor 101 having such a configuration, the shaft 70 sucks the lubricating oil stored in the oil storage space P through the oil supply hole 61, and the sucked lubricating oil is compressed into the compression mechanism 15. It can be supplied to the sliding part.

  The shaft 70 has a substantially round bottom flask shape. Specifically, the shaft 70 is a portion excluding the enlarged portion 71 having a substantially spherical shape formed in the vicinity of the lower end (the vicinity of the lower end) immersed in the lubricating oil and the vicinity of the lower end where the enlarged portion 71 is formed. A substantially cylindrical main shaft portion 72 that extends from the upper end of the enlarged portion 71 to the vicinity of the lower surface of the compression mechanism 15 in the axially upper direction. An upper bearing 33 is connected to the main shaft portion 72 at an upper portion below the upper end portion 74, and a rotor 52 of the drive motor 16 is connected to a substantially central portion thereof. The shaft center of the upper end portion 74 of the main shaft portion 72 is slightly eccentric with respect to the portion other than the upper end portion of the main shaft portion 72 and the shaft center of the enlarged portion 71. The axis center of the main shaft portion 72 excluding the upper end portion 74 and the axis center of the enlarged portion 71 are located on the central axis OO. The shaft 70 is pivotally supported by the upper end bearing 26c by the upper end 74 being fitted into the space inside the upper end bearing 26c. Note that the shaft 70 is connected to the movable scroll 26 by fitting the upper end portion 74 of the shaft 70 into the space inside the upper end bearing 26c.

  Further, the lower portion of the main shaft portion 72 is pivotally supported by the lower bearing 60. The enlarged portion 71 is formed so as to occupy about 80% of the bearing lower portion 73 which is a lower portion of the shaft 70 supported by the lower bearing 60 in the axial direction. More specifically, the bearing lower portion 73 is a portion from a position corresponding to the lower surface of the lower bearing 60 of the shaft 70 to the lower end of the shaft 70.

  The enlarged portion 71 has an elliptical cross section in the axial direction, and is formed so as to be symmetric about the central axis OO. The enlarged portion 71 is formed so as to expand radially outward from the lower end of the main shaft portion 72. Specifically, the enlarged portion 71 is formed so as to expand outward in the radial direction from the upper end (that is, the lower end of the main shaft portion 72) toward the central portion in the axial direction, and toward the lower end in the axial direction from the central portion. Accordingly, it is formed so as to become smaller inward in the radial direction. That is, the enlarged portion 71 is formed such that its outer diameter increases from the upper end and the lower end toward the central portion in the axial direction. Thus, the enlarged portion 71 is formed such that its outer diameter continuously changes in the axial direction, and the outer diameter at the central portion is the maximum outer diameter.

  As described above, the shaft 70 of the present embodiment is formed with the enlarged portion 71 whose outer surface is inclined with respect to the central axis OO in the vicinity of the lower end. More specifically, when the enlarged portion 71 takes an arbitrary point on the outer edge in the cross-sectional shape in the axial direction, the tangent line passing through the points excluding the central point in the axial direction is the central axis OO. It is formed so as to be inclined with respect to.

  Further, the balance weight 18 is fixed to the shaft 70 on the outer peripheral surface located below the upper bearing 33 of the main shaft portion 72 and above the drive motor 16. In the present embodiment, the balance weight 18 is attached to the main shaft portion 72 as a separate body, but may be integrally formed with the main shaft portion 72. The maximum outer diameter of the enlarged portion 71 is larger than the outer diameter of the portion excluding the portion in close contact with the balance weight 18 of the main shaft portion 72. That is, the maximum outer diameter of the enlarged portion 71 is larger than the outer diameter of the reference portion included in the main shaft portion 72. Here, the reference portion is a bearing facing portion described later, or a motor connecting portion 75 to which the rotor 52 of the drive motor 16 is connected. More specifically, the maximum outer diameter of the enlarged portion 71 is 120% of the outer diameter of the lower end of the main shaft portion 72.

  Further, the shaft 70 is formed therein with a first oil supply horizontal hole 61a and a second oil supply horizontal hole 61b branched in the horizontal direction from an oil supply hole 61 extending in the axial direction. The first oil supply lateral hole 61a is formed so that lubricating oil can be supplied to the sliding portions between the upper end bearing 26c and the upper bearing 33 and the shaft 70. The second oil supply lateral hole 61b is formed so that lubricating oil can be supplied to the sliding portion between the lower bearing 60 and the shaft 70.

  As described above, the shaft 70 supplies the lubricating oil stored in the oil storage space P via the oil supply hole 61, the first oil supply horizontal hole 61a, and the second oil supply horizontal hole 61b to each sliding portion (compression mechanism). 15 sliding portions, upper end bearing 26c, sliding portion between upper bearing 33 and shaft 70, and sliding portion between lower bearing 60 and shaft 70). Here, a sliding portion of the shaft 70 that slides with the upper bearing 26c, the upper bearing 33, and the lower bearing 60, and a portion that faces the bearings 26c, 33, 60 in the radial direction, It is called a bearing facing part.

  As described above, the shaft 70 is driven by the drive motor 16 by connecting the compression mechanism 15 (specifically, the movable scroll 26) and the drive motor 16 (specifically, the rotor 52). The force is transmitted to the compression mechanism 15. Specifically, when a current flows through the drive motor 16, first, the rotor 52 rotates counterclockwise around the central axis OO as viewed from above, and this rotational driving force is transmitted to the shaft 70. The shaft 70 rotates counterclockwise as viewed from above. When the shaft 70 rotates, the rotational driving force of the rotor 52 (drive motor 16) is transmitted to the movable scroll 26 (compression mechanism 15) connected to the shaft 70, and the movable scroll 26 is driven. ing.

(1-10) Gas guide 58
The gas guide 58 is a member for guiding the compressed refrigerant flowing through the second communication passage 48 to the high-pressure space S1. The gas guide 58 is fixed to the cylindrical portion 11 of the casing 10, and forms a space for guiding the refrigerant to the high-pressure space S <b> 1 together with the inner peripheral surface of the cylindrical portion 11.

(2) Operation The operation of the scroll compressor 101 will be described. First, the flow of the refrigerant circulating in the refrigerant circuit provided with the scroll compressor 101 will be described, and then the flow of the lubricating oil in the scroll compressor 101 will be described.

(2-1) Flow of refrigerant First, when the drive motor 16 is driven, the rotor 52 rotates. As a result, the shaft 70 fixed to the rotor 52 performs an axial rotation motion. The rotational driving force of the shaft 70 is transmitted to the movable scroll 26 through the upper end bearing 26c. The shaft center of the upper end portion 74 of the shaft 70 is eccentric with respect to the center axis OO, and the movable scroll 26 is prevented from rotating by the Oldham joint 39. Thereby, the movable scroll 26 performs a revolving motion.

  The low-temperature and low-pressure refrigerant before compression is sucked into the compression chamber 40 of the compression mechanism 15 from the suction pipe 19 via the main suction hole or from the low-pressure space S2 via the auxiliary suction hole. By the revolving motion of the movable scroll 26, the volume of the compression chamber 40 is gradually reduced while moving from the outer peripheral portion of the fixed scroll 24 toward the center portion. As a result, the refrigerant in the compression chamber 40 is compressed into a compressed refrigerant. After the compressed refrigerant is discharged from the discharge hole 41 to the muffler space 45, the compressed refrigerant passes through the first communication passage 46 and the second communication passage 48, and the high-pressure space S <b> 1 (specifically, the compression mechanism 15, the drive motor 16, and the like). To the space in the axial direction). A part of the compressed refrigerant flows downward in the space between the gas guide 58 and the cylindrical portion 11 of the casing 10. The compressed refrigerant further descends through the motor cooling passage 55 and reaches the space below the drive motor 16. Thereafter, the compressed refrigerant reverses the flow direction, moves up the motor cooling passage 55 and the air gap, and flows again into the space between the compression mechanism 15 and the drive motor 16 in the axial direction. Finally, the compressed refrigerant is discharged from the discharge pipe 20 to the outside of the casing 10.

(2-2) Flow of lubricating oil First, when the drive motor 16 is driven, the rotor 52 rotates. As a result, the shaft 70 fixed to the rotor 52 performs an axial rotation motion. When the compression mechanism 15 is driven by the shaft rotation of the shaft 70 and the compressed refrigerant is discharged into the high-pressure space S1, the pressure in the high-pressure space S1 increases. Here, the oil supply hole 61 formed in the shaft 70 communicates with the low pressure space S <b> 2 via the oil chamber 83 and the oil supply hole 63. As a result, a pressure difference is generated between the upper end portion and the lower end portion of the oil supply hole 61. As a result, the oil supply hole 61 itself acts as a differential pressure pump, and the lubricating oil stored in the oil storage space P is sucked into the oil supply hole 61 and ascends the oil supply hole 61.

  Lubricating oil that has moved up to the oil chamber 83 through the oil supply hole 61 is supplied to the sliding portion of the compression mechanism 15 via the oil supply hole 63. The lubricating oil that has lubricated the sliding portion of the compression mechanism 15 is discharged from the compression chamber 40 to the high-pressure space S1 through the same path as the compressed refrigerant. Thereafter, the lubricant oil collides with the oil separation plate 65 after descending the motor cooling passage 55 together with the compressed refrigerant. At this time, the lubricating oil adhering to the oil separation plate 65 falls in the high pressure space S1 and is stored in the oil storage space P.

  On the other hand, most of the lubricating oil that is sucked from the oil storage space P and rises through the oil supply hole 61 is divided into the first oil supply horizontal hole 61a and the second oil supply horizontal hole 61b. A part of the lubricating oil divided into the first oil supply lateral hole 61a and the lubricating oil in the oil chamber 83 lubricates the sliding portion between the upper end portion of the shaft 70 and the upper end bearing 26c, and then the upper portion and the upper bearing of the shaft 70. 33 is supplied to the sliding portion. Then, it flows into the high-pressure space S1 and is returned to the oil storage space P. Further, the lubricating oil that is diverted to the second oil supply lateral hole 61b lubricates the sliding portion between the lower portion of the shaft 70 and the lower bearing 60 and leaks into the high-pressure space S1, and then the high-pressure space S1 enters the oil storage space P. To fall.

  Thus, the cycle in which the lubricating oil stored in the oil storage space P is supplied to each sliding portion and returns to the oil storage space P is repeated.

(3) Features (3-1)
Generally, in a scroll compressor, depending on a pressure state or a temperature state, it is conceivable that refrigerant and lubricating oil are separated in an oil storage space. And if it isolate | separates so that a refrigerant | coolant may be located under lubricating oil, since an oil supply hole is opening below, there is a concern that a lot of refrigerant flows in an oil supply hole and lubricating oil does not flow so much. . Since the refrigerant has a viscosity much lower than that of the lubricating oil, when such a state occurs, the sliding part of the compression mechanism, the sliding part of the shaft with the upper bearing and the upper bearing, and the sliding of the lower part of the shaft with the lower bearing There is a concern that poor lubrication may occur in moving parts and the like. In particular, when a refrigerant (R32 refrigerant) that is easily separated from the lubricating oil as in the present embodiment is used, there is a concern that this tendency becomes remarkable.

  Therefore, in this embodiment, even if the refrigerant and the lubricating oil are separated in the oil storage space P, a part of the shaft 70 is enlarged so that a large amount of the lubricating oil can flow through the oil supply hole 61. The conventional shaft is formed to have a substantially cylindrical shape from the upper end to the lower end (that is, the conventional shaft is formed so that the outer surface thereof is parallel to the central axis of the drive motor. )

  Specifically, the shaft 70 of the present embodiment is different from the substantially cylindrical main shaft portion 72 in a part (a lower end vicinity portion that is a vicinity of a lower end immersed in the lubricating oil stored in the oil storage space P). It has an enlarged portion 71 of a different shape. Specifically, the shaft 70 has a spherical enlarged portion 71 swelled radially outward in the vicinity of the lower end. More specifically, the enlarged portion 71 is formed so as to expand radially from the lower end of the main shaft portion 72 and so that the outer surface is inclined with respect to the central axis OO.

  Here, when the shaft 70 is rotated, in the lubricating oil (specifically, lubricating oil and refrigerant) stored in the oil storage space P, the rotating flow rotates along the outer surface in the vicinity of the lower end of the shaft 70. Will occur. In the present embodiment, since the enlarged portion 71 is formed in the vicinity of the lower end of the shaft 70, lubricating oil (lubricating oil and refrigerant) generated around the outer surface of the enlarged portion 71 of the shaft 70. Can be changed in the axial direction (see the arrow indicated by the thick line in FIG. 2). In other words, the pressure at the portion where the rotational flow is fast is reduced, and the pressure at the portion where the rotational flow is slow is increased, so that the rotational flow is different in the axial direction. And since the pressure difference can be produced in the axial direction by the speed difference in the axial direction of the rotational flow, the axial flow can be produced in the fluid in the oil storage space P. Therefore, even if the refrigerant and the lubricating oil are separated into two layers in the oil storage space P, the refrigerant and the lubricating oil can be mixed. Therefore, a large amount of lubricating oil can be supplied to the oil supply hole 61 formed in the shaft 70, and poor lubrication at each sliding portion in the scroll compressor 101 can be suppressed.

  Thus, in the present embodiment, the reliability of the scroll compressor 101 can be improved with a simple structure in which the enlarged portion 71 is formed on the shaft 70.

  In this embodiment, the shaft 70 is formed with a spherical enlarged portion 71 at a portion (approximately the lower end portion) of about 80% of the bearing lower portion 73. The shaft 70 has a maximum outer diameter of the enlarged portion 71 that is 120% of the outer diameter of the lower end of the main shaft portion 72. In the present embodiment, the shaft 70 is formed in this way, so that it is easier to mix the refrigerant and the lubricating oil even when the refrigerant and the lubricating oil are separated.

(3-2)
In the present embodiment, the shaft 70 is formed so that the outer diameter of the enlarged portion 71 continuously changes in the axial direction. Thereby, when the shaft 70 rotates axially, the speed of the rotational flow of the lubricating oil (lubricating oil and refrigerant) generated around the outer surface of the enlarged portion 71 of the shaft 70 continuously changes in the axial direction. Can be made. Therefore, even if the refrigerant and the lubricating oil are separated into a two-layer state in the oil storage space P, they are more easily mixed.

(3-3)
In the present embodiment, the shaft 70 is formed so that the enlarged portion 71 is symmetric about the central axis OO. As a result, as described above, even if the shape of a part of the shaft 70 (the vicinity of the lower end) is enlarged, an increase in power loss can be suppressed.

(4) Modification (4-1) Modification A
FIG. 3 is a schematic diagram showing the periphery of the enlarged portion 71 of the shaft 70 showing another ratio of the enlarged portion 71 to the bearing lower portion 73.

  In the above embodiment, the shaft 70 has been described as having the enlarged portion 71 formed in about 80% of the bearing lower portion 73, but the present invention is not limited to this, and more than half of the bearing lower portion 73. It suffices if the enlarged portion 71 is formed. Specifically, for example, as shown in FIG. 3, the enlarged portion 71 may be formed to occupy half of the bearing lower portion 73.

  Moreover, although the said embodiment demonstrated that the maximum outer diameter of the enlarged part 71 formed in the lower end vicinity part of the shaft 70 was 120% of the outer diameter of the lower end of the main axis | shaft part 72, it is not restricted to this. Without exceeding 120% of the outer diameter of the lower end of the main shaft portion 72.

  Even in the above case, the same effect as the above embodiment can be obtained.

(4-2) Modification B
In the above-described embodiment, the ratio of the enlarged portion 71 is described using the lower bearing 60 as a reference, and the bearing lower portion 73 that is a portion from the position corresponding to the lower surface of the lower bearing 60 to the lower end is used as a reference. It can be shown by other methods.

  Specifically, the ratio occupied by the enlarged portion 71 may be shown based on the oil level height when the lubricating oil is stored most in the oil storage space P. In this case, the enlarged portion 71 only needs to occupy more than half of the portion below the oil level of the shaft 70 in the axial direction. That is, the shaft 70 in this case has the enlarged portion 71 formed in more than half of the portion immersed in the lubricating oil. Even in this case, the same effects as described above can be obtained.

(4-3) Modification C
4 and 5 are schematic views showing other shapes of the enlarged portion 71 of the shaft 70. FIG.

  In the above embodiment, the shaft 70 has been described as having an elliptical cross-sectional shape in the axial direction of the enlarged portion 71. However, the present invention is not limited to this, and the shaft 70 is formed in the enlarged portion 71. The outer surface may be formed so as to extend radially outward from the lower end of the main shaft portion 72 and to be inclined with respect to the central axis OO. This is because the outer diameter in the axial direction can be changed in the enlarged portion 71 and the axial flow can be generated in the lubricating oil stored in the oil storage space P. Therefore, the cross-sectional shape in the axial direction of the enlarged portion 71 may be formed in a rhombus shape.

  For example, the shaft 70 may be formed such that the enlarged portion 71 has a substantially triangular pyramid shape. Specifically, as shown in FIG. 4, the shaft 70 has an enlarged portion 71 such that one of the three vertices is positioned on the central axis OO in the axial sectional shape. And it may be formed so as to have an inverted triangular shape that expands in the radial direction upward from one vertex located on the central axis OO. That is, in the shaft 70 having this configuration, the upper end of the enlarged portion 71 has the maximum outer diameter, and the upper end extends from the lower end of the main shaft portion 72 radially outward. Further, in the shaft 70 having this configuration, the outer surface of the enlarged portion 71 is inclined with respect to the central axis OO. Specifically, the outer surface is inclined with respect to the central axis OO so as to be separated from the lower side in the axial direction toward the upper side in the axial direction. Further, the shaft 70 having this configuration has its outer diameter continuously changing in the axial direction. Specifically, the outer diameter decreases from the upper side in the axial direction toward the lower side in the axial direction. In addition, when forming the shaft 70 in this way, in order to suppress the occurrence of cavitation for the two apex portions excluding the one apex located on the central axis OO in the cross-sectional view cut in the axial direction, R processing is desirable.

  For example, as shown in FIG. 5, the shaft 70 may have a substantially conical flask shape. Specifically, the shaft 70 may have a trapezoidal shape in which the enlarged portion 71 expands radially outward as it goes downward from the lower end of the main shaft portion 72 in the cross-sectional shape in the axial direction. That is, in the shaft 70 having this configuration, the lower end of the enlarged portion 71 has the maximum outer diameter. Further, in the shaft 70 having this configuration, the outer surface of the enlarged portion 71 is inclined with respect to the central axis OO. Specifically, the outer surface is inclined with respect to the central axis OO so as to be separated from the upper side in the axial direction toward the lower side in the axial direction. Further, the shaft 70 having this configuration has its outer diameter continuously changing in the axial direction. Specifically, the outer diameter increases from the upper axial direction to the lower axial direction.

  As described above, even with the shaft 70 having the configuration shown in the present modification, the same operational effects as described above can be obtained.

(4-4) Modification D
In the above-described embodiment, the scroll compressor including the fixed scroll 24 and the movable scroll 26 and including the compression mechanism 15 has been described as the compressor according to the present invention. However, the compressor is not limited to the scroll compressor. The present invention is applicable, for example, to a compressor in which the end of the shaft that transmits the driving force of the drive motor to the compression mechanism is immersed in the lubricating oil, and a hole through which the lubricating oil flows is formed in the shaft.

(4-5) Modification E
In the above embodiment, the case where the main shaft portion 72 and the enlarged portion 71 are integrally formed has been described. However, the present invention is not limited to this, and the main shaft portion 72 and the enlarged portion 71 are separate. Also good. In this case, the material constituting the enlarged portion 71 is desirably the same as the material constituting the main shaft portion 72. In this case, the enlarged portion 71 functions as a pump that sucks the lubricating oil into the oil supply hole 61. Even in this case, it is possible to obtain the same effect as the above embodiment.

  The present invention can be applied to a compressor in which an end portion of a shaft that transmits a driving force of a drive motor to a compression mechanism is immersed in the lubricating oil, and a hole through which the lubricating oil flows is formed in the shaft.

DESCRIPTION OF SYMBOLS 10 Casing 15 Compression mechanism 16 Drive motor 60 Lower bearing 61 Oil supply hole (hole)
70 Shaft 71 Enlarged part 73 Bearing lower part (the part below the lower bearing of the shaft)
75 Motor connecting part 101 Scroll compressor (compressor)
P Oil storage space

JP 2010-285930 A

Claims (6)

A compression mechanism (15) for compressing the refrigerant;
A drive motor (16) for driving the compression mechanism;
A hollow shaft (70) connected to the compression mechanism and the drive motor, for transmitting a driving force of the drive motor to the compression mechanism, and having an axially extending hole (61);
A casing (10) in which the compression mechanism, the drive motor, and the shaft are accommodated, and an oil storage space (P) in which lubricating oil is stored and a lower end of the shaft is immersed in the lubricating oil is formed at the bottom of the internal space. )When,
With
The shaft has an enlarged portion (71) formed in the vicinity of the lower end of the lower end thereof,
The enlarged portion is formed so as to expand radially outward from the lower end of the main shaft portion (72) excluding the enlarged portion and so that the outer surface is inclined with respect to the central axis (OO) of the drive motor. Yes,
Compressor (101). The shaft is formed such that the outer diameter of the enlarged portion continuously changes in the axial direction.
The compressor according to claim 1. The shaft is formed such that the maximum outer diameter of the enlarged portion is 120% or more of the outer diameter of the lower end of the main shaft portion.
The compressor according to claim 1 or 2. The shaft is formed so that the enlarged portion is symmetric about the central axis.
The compressor according to any one of claims 1 to 3. The enlarged portion is half or more in the axial direction of the portion below the oil level height of the shaft when the oil level height is the reference when the most lubricating oil is stored in the oil storage space. Occupy
The compressor according to any one of claims 1 to 4. A lower bearing (60) for pivotally supporting the lower portion of the shaft,
The enlarged portion occupies more than half in the axial direction of the portion (73) below the portion supported by the lower bearing of the shaft,
The compressor according to any one of claims 1 to 4.

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