Compressors and refrigeration cycle equipment

Abstract

This invention provides a compressor and refrigeration cycle system that feature a three-cylinder rotary compression mechanism, yet allow for easy and highly accurate bearing alignment, resulting in superior manufacturability and reliability. [Solution] The compressor 3 comprises a sealed container 15, an electric motor 17, a three-cylinder rotary compression mechanism 19 having a first cylinder 39A, a second cylinder 39B, and a third cylinder 39C arranged in order from closest to the electric motor 17, and a crankshaft 21 having a main shaft portion 21a, an intermediate shaft portion 21c, and a sub-shaft portion 21b. The compression mechanism 19 comprises a main bearing 23 that rotatably supports the main shaft portion 21a between the electric motor 17 and the first cylinder 39A, an intermediate bearing 25 that rotatably supports the intermediate shaft portion 21c between the second cylinder 39B and the third cylinder 39C, and a lower end portion 26 that is located on the side further from the third cylinder 39C when viewed from the second cylinder 39B and supports the thrust load of the crankshaft 21.

Description

Technical Field

[0001] The present invention relates to a compressor and a refrigeration cycle device.

Background Art

[0002] There is known a compressor including a sealed container, a three-cylinder rotary compression mechanism for compressing a refrigerant introduced into the sealed container, a rotating shaft having a main shaft portion, an intermediate shaft portion, and a sub-shaft portion, and an electric motor portion connected to the compression mechanism via the rotating shaft to drive the compression mechanism. The compression mechanism includes a main bearing that rotatably supports the main shaft portion of the rotating shaft, an intermediate bearing that rotatably supports the intermediate shaft portion of the rotating shaft, and a sub-bearing that rotatably supports the sub-shaft portion of the rotating shaft. The rotating shaft is also called a crankshaft.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in a conventional compressor, the shaft alignment process of adjusting the three bearings of the main bearing, the intermediate bearing, and the sub-bearing substantially on the same axis of the crankshaft requires complicated and careful work. Therefore, the manufacturing management of the compressor becomes more complicated due to the shaft alignment process of the three bearings. Further, if there is variation in the accuracy of shaft alignment, there is a risk of reducing the slidability of the bearing portion and thus the reliability. Therefore, in a compressor having a three-cylinder rotary compression mechanism, it is desirable that easy and highly accurate shaft alignment of the bearings can be performed.

[0005] Therefore, an object of the present invention is to provide a compressor and a refrigeration cycle device that can easily and highly accurately align the shafts of bearings while having a three-cylinder rotary compression mechanism, and that are excellent in manufacturability and reliability. [Means for solving the problem]

[0006] To solve the aforementioned problems, a compressor according to an embodiment of the present invention comprises: a cylindrical sealed container; an electric motor disposed within the sealed container; a three-cylinder rotary compression mechanism disposed within the sealed container and capable of compressing a refrigerant, having a first cylinder, a second cylinder, and a third cylinder spaced apart from the electric motor in order of proximity; and a crankshaft that transmits the rotational driving force of the electric motor to the compression mechanism, having a cylindrical main shaft portion located between the electric motor and the first cylinder; a cylindrical intermediate shaft portion located between the second cylinder and the third cylinder; and a cylindrical sub-shaft portion located on the opposite side of the intermediate shaft portion, with the third cylinder in between. The compression mechanism comprises a main bearing located between the electric motor and the first cylinder that rotatably supports the main shaft portion; an intermediate bearing located between the second cylinder and the third cylinder that rotatably supports the intermediate shaft portion; and a lower end portion located on the side further from the third cylinder as viewed from the second cylinder that supports the thrust load of the crankshaft.

[0007] Furthermore, in order to solve the above-mentioned problems, the refrigeration cycle apparatus according to the embodiment of the present invention comprises a compressor, a heat sink, an expansion device, a heat absorber, and refrigerant piping that connects the compressor, the heat sink, the expansion device, and the heat absorber and allows the refrigerant to flow. [Brief explanation of the drawing]

[0008] [Figure 1] A schematic diagram of a refrigeration cycle device and compressor according to an embodiment of the present invention. [Figure 2] Enlarged view of the area around the compression mechanism in Figure 1. [Figure 3] A schematic diagram showing a first example of the procedure for arranging an intermediate bearing on the crankshaft in a compressor according to an embodiment of the present invention. [Figure 4]A schematic diagram showing a second example of the procedure for arranging an intermediate bearing on the crankshaft in a compressor according to an embodiment of the present invention. [Modes for carrying out the invention]

[0009] Embodiments of the compressor and refrigeration cycle device according to the present invention will be described with reference to Figures 1 to 4. Note that the same or corresponding components are denoted by the same reference numerals in multiple drawings.

[0010] Figure 1 is a schematic diagram of a refrigeration cycle device and compressor according to an embodiment of the present invention.

[0011] As shown in Figure 1, the refrigeration cycle device 1 comprises a sealed rotary compressor 3, a radiator 5, an expansion device 7, a heat absorber 9, and refrigerant piping 11. The refrigerant piping 11 sequentially connects the compressor 3, the radiator 5, the expansion device 7, and the heat absorber 9 to circulate the refrigerant. The radiator 5 is also called a condenser. The heat absorber 9 is also called an evaporator. Hereinafter, the rotary compressor 3 may be simply referred to as the compressor 3.

[0012] The compressor 3 draws in the refrigerant that has passed through the heat absorber 9 via the refrigerant piping 11, compresses it, and discharges the high-temperature, high-pressure refrigerant to the heat radiator 5 via the refrigerant piping 11.

[0013] The compressor 3 comprises a vertically positioned cylindrical sealed container 15, an electric motor 17 located in the upper half of the sealed container 15, a compression mechanism 19 located in the lower half of the sealed container 15, a crankshaft 21 that transmits the rotational driving force of the electric motor 17 to the compression mechanism 19, a main bearing 23 that rotatably supports the crankshaft 21, an intermediate bearing 25 that cooperates with the main bearing 23 to rotatably support the crankshaft 21, and an accumulator 27.

[0014] The sealed container 15 comprises a cylindrical body 15a extending vertically, an upper end plate 15b that closes the upper end of the body, and a lower end plate 15c that closes the lower end of the body 15a.

[0015] A discharge pipe 11b for discharging refrigerant is connected to the upper end plate 15b of the sealed container 15. The discharge pipe 11b is connected to the refrigerant piping 11. In addition, a sealed terminal section 28 for power supply is provided on the upper end plate 15b of the sealed container 15.

[0016] The electric motor 17 generates a driving force to rotate the compression mechanism 19. The electric motor 17 is positioned above the compression mechanism 19. The electric motor 17 comprises a cylindrical stator 29 fixed to the inner surface of the sealed container 15, a rotor 31 positioned inside the stator 29 to rotate the compression mechanism 19, and a plurality of lead wires 33 drawn out from the stator 29 and connected to the sealed terminal section 28.

[0017] The stator 29 is a concentrated winding stator. The stator 29 comprises a stator core 34 having a cylindrical yoke, a so-called yoke, a plurality of teeth that protrude inward from the yoke and are spaced apart and arranged circumferentially, and a plurality of slots (all not shown) which are spaces provided between adjacent teeth. The stator 29 also comprises two insulating end plates 35A and 35B provided on the respective end faces 34a and 34b of the stator core 34, windings (not shown) wound between each of the plurality of teeth and the two insulating end plates 35A and 35B, and a plurality of insulating thin plates (not shown) sandwiched between each winding.

[0018] The rotor 31 comprises a rotor core 32 having magnet housing holes (not shown) and permanent magnets (not shown) housed in the magnet housing holes. The rotor 31 is fixed to the crankshaft 21. The rotational centerlines C of the rotor 31 and the crankshaft 21 substantially coincide with the centerline of the stator 29. In the following description, the direction along the rotational centerline C may be referred to as the axial direction, the direction of rotation around the rotational centerline C as the circumferential direction, and the direction perpendicular to the axial and circumferential directions as the radial direction.

[0019] The multiple lead wires 33 are wiring that supplies power to the stator 29 through the sealed terminal section 28, and are so-called lead wires. Multiple lead wires 33 are wired depending on the type of motor 17.

[0020] The crankshaft 21 connects the electric motor 17 and the compression mechanism 19. The crankshaft 21 transmits the rotational driving force generated by the electric motor 17 to the compression mechanism 19.

[0021] The crankshaft 21 has a cylindrical main shaft portion 21a located at the intermediate portion of the crankshaft 21, a cylindrical sub-shaft portion 21b located at the lower end portion of the crankshaft 21, and a cylindrical intermediate shaft portion 21c located between the main shaft portion 21a and the sub-shaft portion 21b. The main shaft portion 21a connects the electric motor 17 and the compression mechanism 19 and is rotatably supported by the main bearing 23. The intermediate shaft portion 21c is rotatably supported by the intermediate bearing 25. The main bearing 23 and the intermediate bearing 25 are also part of the compression mechanism 19. Also, the main bearing 23 includes the upper end (one end) of the compression mechanism 19.

[0022] Further, the crankshaft 21 has a plurality of eccentric portions 36 between the main shaft portion 21a supported by the main bearing 23 and the sub-shaft portion 21b located at the lower end of the crankshaft 21. Each eccentric portion 36 is a cylinder having a center line that does not coincide with and is parallel to the rotation center line C of the crankshaft 21.

[0023] The compression mechanism 19 compresses a refrigerant, that is, a single refrigerant or a mixed refrigerant. When the electric motor 17 rotationally drives the crankshaft 21, the compression mechanism 19 sucks in gaseous refrigerant from the refrigerant pipe 11, compresses it, and discharges it into the sealed container 15.

[0024] Figure 2 is an enlarged view of the periphery of the compression mechanism in Figure 1.

[0025] As shown in Figure 2 in addition to Figure 1, the compression mechanism 19 according to this embodiment is a three-cylinder rotary type. In other words, the compressor 3 of this embodiment is a three-cylinder rotary compressor. The compression mechanism 19 comprises a plurality of cylinders 39, each having a circular cylinder chamber 37; a plurality of annular rollers 41 arranged within each cylinder chamber 37; and blades 42 arranged radially in the cylinder chamber 37 within each cylinder 39. The cylinder chamber 37 is the space inside the cylinder 39. The cylinder chamber 37 houses the eccentric portion 36 of the crankshaft 21.

[0026] Note that in the examples shown in Figures 1 and 2, only the blade 42 located in the cylinder chamber 37 of the second cylinder 39B is illustrated.

[0027] Furthermore, the cylinder 39 closest to the electric motor 17 is designated as the first cylinder 39A, the cylinder 39 furthest from the electric motor 17 is designated as the third cylinder 39C, and the cylinder 39 positioned between the first cylinder 39A and the third cylinder 39C is designated as the second cylinder 39B. In other words, the compression mechanism 19 comprises the first cylinder 39A, the second cylinder 39B, and the third cylinder 39C, which are spaced apart in order of proximity to the electric motor 17. Additionally, the eccentric portion 36 housed in the cylinder chamber 37 of the first cylinder 39A is designated as the first eccentric portion 36A, the eccentric portion 36 housed in the cylinder chamber 37 of the second cylinder 39B is designated as the second eccentric portion 36B, and the eccentric portion 36 housed in the cylinder chamber 37 of the third cylinder 39C is designated as the third eccentric portion 36C. In other words, the crankshaft 21 has a first eccentric portion 36A located inside the first cylinder 39A, a second eccentric portion 36B located inside the second cylinder 39B, and a third eccentric portion 36C located inside the third cylinder 39C. Furthermore, focusing on the positions of each shaft portion of the crankshaft 21, the main shaft portion 21a of the crankshaft 21 is located between the electric motor 17 and the first cylinder 39A, the intermediate shaft portion 21c is located between the second cylinder 39B and the third cylinder 39C, and the sub-shaft portion 21b is located on the opposite side of the intermediate shaft portion 21c, with the third cylinder 39C in between.

[0028] Furthermore, the compression mechanism 19 includes a main bearing 23 that closes the upper surface of the first cylinder 39A, a partition plate 43 that closes the lower surface of the first cylinder 39A and the upper surface of the second cylinder 39B, an intermediate bearing 25 that closes the lower surface of the second cylinder 39B and the upper surface of the third cylinder 39C, and a lower end portion 26 that closes the lower surface of the third cylinder 39C. In other words, the compression mechanism 19 includes a main bearing 23 located between the electric motor 17 and the first cylinder 39A that rotatably supports the main shaft portion 21a, a partition plate 43 located between the first cylinder 39A and the second cylinder 39B, an intermediate bearing 25 located between the second cylinder 39B and the third cylinder 39C that rotatably supports the intermediate shaft portion 21c, and a lower end portion 26 located on the side further away from the third cylinder 39C when viewed from the second cylinder 39B.

[0029] The intermediate bearing 25 also serves as a partition plate separating the second cylinder 39B and the third cylinder 39C. The lower end portion 26 includes the lower end (other end) of the compression mechanism 19. The main bearing 23, the first cylinder 39A, the partition plate 43, the second cylinder 39B, the intermediate bearing 25, the third cylinder 39C, and the lower end portion 26 are integrally fixed to a frame that is welded to the sealed container 15 at multiple points, for example by spot welding, using fastening members 45.

[0030] The main bearing 23 is provided with a first discharge valve mechanism 23a for discharging the refrigerant compressed in the cylinder chamber 37 of the first cylinder 39A, and a discharge muffler 47 that covers the first discharge valve mechanism 23a. The first discharge valve mechanism 23a opens a discharge port (not shown) when the pressure difference between the pressure in the cylinder chamber 37 of the first cylinder 39A and the pressure in the discharge muffler 47 reaches a predetermined value due to the compression action of the compression mechanism 19, and discharges the compressed refrigerant into the discharge muffler 47.

[0031] The partition plate 43 is provided with a second discharge valve mechanism 43a for discharging the refrigerant compressed in the cylinder chamber 37 of the second cylinder 39B, and a discharge chamber 43b. The main bearing 23, the first cylinder 39A, and the partition plate 43 have holes (not shown) that connect the discharge chamber 43b to the discharge muffler 47. The second discharge valve mechanism 43a opens its discharge port and discharges the compressed refrigerant into the discharge chamber 43b when the pressure difference between the pressure in the cylinder chamber 37 of the second cylinder 39B and the pressure in the discharge chamber 43b reaches a predetermined value due to the compression action of the compression mechanism 19.

[0032] The discharge muffler 47 has a discharge port (not shown) that connects the inside and outside of the discharge muffler 47. The compressed refrigerant discharged into the discharge muffler 47 is discharged into the sealed container 15 through the discharge port.

[0033] Furthermore, the compressor 3 is equipped with multiple suction pipes 51 that connect the compression mechanism 19 and the accumulator 27. The suction pipes 51 are pipes that guide refrigerant to the cylinder 39. The suction pipes 51 pass through the sealed container 15 and are connected to the cylinder chamber 37 of the cylinder 39. The cylinder 39 has a suction port that connects to the suction pipes 51 and reaches the cylinder chamber 37. The suction pipe 51 connected to the cylinder chamber 37 of the first cylinder 39A is designated as the first suction pipe 51A, and the suction pipes 51 connected to the cylinder chamber 37 of the second cylinder 39B and the cylinder chamber 37 of the third cylinder 39C are designated as the second suction pipes 51B.

[0034] The lower part of the sealed container 15 is filled with lubricating oil (refrigerant oil). The majority of the compression mechanism 19 is immersed in the lubricating oil inside the sealed container 15.

[0035] The accumulator 27 prevents liquid refrigerant that was not completely vaporized by the heat absorber 9 from being drawn into the compression mechanism 19.

[0036] Next, the cylinder 39 of the compression mechanism 19 will be explained further.

[0037] Since the first cylinder 39A, the second cylinder 39B, and the third cylinder 39C have similar structures, only one cylinder 39 will be described.

[0038] In the cylinder 39, the blade 42 reciprocates in contact with the outer surface of the roller 41. The blade 42 divides the cylinder chamber 37 into a suction chamber and a compression chamber. The suction chamber is the part connected to the suction hole provided in the cylinder 39.

[0039] The roller 41 is fitted onto the outer circumferential surface of the eccentric portion 36. The outer circumferential surface of the roller 41 is in line contact with the inner circumferential surface of the cylinder chamber 37. As the crankshaft 21 rotates, the roller 41 undergoes eccentric motion while maintaining line contact between its outer circumferential surface and the inner circumferential surface of the cylinder chamber 37.

[0040] Note that the contact between the roller 41 and the cylinder 39 is not direct, but indirect, mediated by a lubricating oil film (not shown). However, for the sake of explanation, this contact mediated by the oil film will simply be referred to as "contact." The same applies to the spaces between the roller 41 and the eccentric portion 36, the roller 41 and the main bearing 23, the roller 41 and the lower end portion 26, the roller 41 and the partition plate 43, and the roller 41 and the intermediate bearing 25.

[0041] As mentioned above, in conventional compressors, it is extremely difficult to stably and accurately align the three bearings—the main bearing, intermediate bearing, and auxiliary bearing—on nearly the same axis during the manufacturing process. Therefore, manufacturing control of compressors becomes more complex. Furthermore, if there is variation in the precision of the axial alignment, it may reduce the sliding performance of the bearing section and, consequently, its reliability. For this reason, it is desirable that the axial alignment process in a three-cylinder rotary compressor be able to easily and accurately align the bearings.

[0042] Therefore, in the compressor 3 according to this embodiment, the lower end portion 26 of the compression mechanism 19 supports the thrust load of the crankshaft 21 without supporting the radial load of the sub-shaft portion 21b. A radial load is a load generated in the radial direction, and a thrust load is a load generated in the axial direction.

[0043] Generally, bearings supporting the crankshaft in a compressor require axial alignment when supporting radial loads. However, unlike the sub-bearings of conventional compressors, the lower end portion 26 of this embodiment does not support the radial load of the sub-shaft portion 21b. In other words, the lower end portion 26 does not require axial alignment, which is performed on the sub-bearings of conventional compressors. Therefore, in compressor 3, only the main bearing 23 and the intermediate bearing 25 require axial alignment. Consequently, in compressor 3, bearing axial alignment can be performed more easily and accurately compared to conventional compressors that require axial alignment of three bearings: the main bearing, the intermediate bearing, and the sub-bearing.

[0044] Furthermore, the crankshaft 21 can be adequately supported by the two bearings, the main bearing 23 and the intermediate bearing 25, without deflecting during the operation of the compressor 3. Also, since the radial load of the sub-shaft portion 21b is not supported by the lower end portion 26, the third eccentric portion 36C and the sub-shaft portion 21b are cantilevered by the intermediate bearing 25. In addition, since the lower end portion 26 does not support the radial load of the sub-shaft portion 21b, the axial length of the sub-shaft portion 21b can be shortened compared to the sub-shaft portion of a conventional compressor.

[0045] Furthermore, as shown in Figure 2, it is preferable that the compressor 3 of this embodiment satisfies the following relationships (1) to (4) when the outer diameter of the first eccentric part 36A is D1, the outer diameter of the second eccentric part 36B is D2, the outer diameter of the third eccentric part 36C is D3, the eccentricity of the first eccentric part 36A is E1, the eccentricity of the second eccentric part 36B is E2, the eccentricity of the second eccentric part 36B is E3, the outer diameter (shaft diameter) of the intermediate shaft part 21c is Dm, the distance (spacing) between the first eccentric part 36A and the second eccentric part 36B, that is, the distance between the lower end of the first eccentric part 36A and the upper end of the second eccentric part 36B is Lb, and the length of the intermediate bearing 25 in the axial direction is Lm. (Outer diameter D1)=(Outer diameter D2)=(Outer diameter D3) (1) (Eccentricity E1)=(Eccentricity E2)=(Eccentricity E3) (2) (Outer diameter Dm)>((Outer diameter D1) / 2+(Eccentricity E1))×2 (3) (Length Lb) > (Length Lm) (4)

[0046] By satisfying the above relationships (1) to (4), the intermediate bearing 25 can be inserted into the intermediate shaft portion 21c from either the upper or lower end of the crankshaft 21. This alleviates the constraints on the assembly of the three-cylinder rotary compression mechanism 19, enabling a more flexible assembly of the compression mechanism 19. As a result, the ease of assembly of the compression mechanism 19 is improved, and consequently, the manufacturability of the compressor 3 is improved.

[0047] The intermediate shaft portion 21c supports the third eccentric portion 36C, the roller 41, and the sub-shaft portion 21b by cantilever support. The intermediate shaft portion 21c has the rigidity to support the reaction force due to centrifugal force and compressive pressure applied to the third eccentric portion 36C and the roller 41. In order to ensure sufficient rigidity of the intermediate shaft portion 21c, it is preferable that the axial length of the intermediate shaft portion 21c is longer than the axial length of the third cylinder 39C. In this case, the axial length of the intermediate bearing 25 that rotatably supports the intermediate shaft portion 21c is also longer than the axial length of the third cylinder 39C.

[0048] Figure 3 is a schematic diagram showing a first example of the procedure for arranging an intermediate bearing on the crankshaft in a compressor according to an embodiment of the present invention.

[0049] Now, referring to Figure 3, the procedure for inserting the intermediate bearing 25 from the upper end of the crankshaft 21 and positioning it on the intermediate shaft portion 21c will be described. The intermediate bearing 25 has a circular through hole 25a to support the intermediate shaft portion 21c of the crankshaft 21.

[0050] Specifically, in state S1 in Figure 3, the intermediate bearing 25 is inserted into the crankshaft 21 from the upper end side of the crankshaft 21 so that the rotational centerline C of the crankshaft 21 coincides with the centerline of the through-hole 25a of the intermediate bearing 25. In state S2 following state S1, as the intermediate bearing 25 passes through the first eccentric portion 36A, the centerline of the through-hole 25a of the intermediate bearing 25 is made to coincide with the centerline of the first eccentric portion 36A. In state S3 following state S2, when the intermediate bearing 25 reaches between the lower end of the first eccentric portion 36A and the upper end of the second eccentric portion 36B, the intermediate bearing 25 is moved in a direction perpendicular to the rotational centerline C so that the centerline of the through-hole 25a of the intermediate bearing 25 coincides with the rotational centerline C of the crankshaft 21, resulting in state S4. In other words, by satisfying the above relational equation (4), the intermediate bearing 25 can be moved to result in state S4. Then, in state S5, which follows state S4, the intermediate bearing 25 is positioned to support the intermediate shaft portion 21c.

[0051] Furthermore, as shown in Figure 2, it is preferable that the compressor 3 of this embodiment satisfies the following relationships (1') to (3') when the outer diameter of the first eccentric part 36A is D1, the outer diameter of the second eccentric part 36B is D2, the outer diameter of the third eccentric part 36C is D3, the eccentricity of the first eccentric part 36A is E1, the eccentricity of the second eccentric part 36B is E2, the eccentricity of the third eccentric part 36C is E3, and the outer diameter of the intermediate shaft part 21c is Dm. (Outer diameter D1)=(Outer diameter D2)>(Outer diameter D3) (1′) (Eccentricity E1)=(Eccentricity E2)=(Eccentricity E3) (2′) (Outer diameter Dm)>((Outer diameter D3) / 2+(Eccentricity E3))×2 (3′)

[0052] When the above relationships (1') to (3') are satisfied, the insertion of the intermediate bearing 25 from the upper end of the crankshaft 21 is restricted, and it can only be inserted into the intermediate shaft portion 21c from the lower end of the crankshaft 21. Although the insertion of the intermediate bearing 25 from the upper end of the crankshaft 21 is restricted, the outer diameter D3 of the third eccentric portion 36C of the crankshaft 21 can be made as small as possible without impairing the performance of the compressor 3. In general, reducing the outer diameter of each shaft portion and eccentric portion of the crankshaft reduces the sliding loss in each shaft portion and eccentric portion when the compressor is in operation. In other words, the sliding performance of each shaft portion and eccentric portion is improved, and consequently, the reliability of the compressor is improved. Therefore, when the above relationships (1') to (3') are satisfied, the outer diameter Dm of the intermediate shaft portion 21c can be reduced while ensuring the sliding performance and reliability of the third eccentric portion 36C. In other words, the sliding loss of the intermediate shaft portion 21c and the third eccentric portion 36C is reduced, improving the efficiency of the compression mechanism 19 and, consequently, the compressor 3.

[0053] Figure 4 is a schematic diagram showing a second example of the procedure for arranging an intermediate bearing on the crankshaft in a compressor according to an embodiment of the present invention.

[0054] Now, referring to Figure 4, the procedure for inserting the intermediate bearing 25 from the lower end of the crankshaft 21 and positioning it in the intermediate shaft portion 21c will be explained.

[0055] Specifically, in state S1' in Figure 4, the intermediate bearing 25 is inserted into the crankshaft 21 from the lower end side of the crankshaft 21 so that the rotational centerline C of the crankshaft 21 coincides with the centerline of the through hole 25a of the intermediate bearing 25. In state S2' following state S1', the intermediate bearing 25 continues along the rotational centerline C and passes through the third eccentric portion 36C. Then, in state S3' following state S2', the intermediate bearing 25 is positioned to support the intermediate shaft portion 21c located above the third eccentric portion 36C.

[0056] Furthermore, as shown in Figure 2, the lower end portion 26 of the compression mechanism 19 preferably has a thrust plate 59 having a lubrication inlet hole 57 which is a through hole provided to contact the end face (lower end face) of the sub-shaft portion 21b of the crankshaft 21 and to be aligned with the rotational centerline C of the crankshaft 21, and a sub-shaft plate 63 located between the thrust plate 59 and the third cylinder 39C and having a through hole 61 in which the sub-shaft portion 21b of the crankshaft 21 is positioned. Furthermore, it is preferable that a gap Lg is provided around the entire circumference between the inner circumferential surface 61a of the through hole 61 and the outer circumferential surface 21ba of the sub-shaft portion 21b. In other words, it is preferable that the outer circumferential surface 21ba of the sub-shaft portion 21b faces the inner circumferential surface 61a of the through hole 61 of the sub-shaft plate 63 at a certain distance.

[0057] Specifically, the thrust plate 59 is a flat plate member that supports the sub-shaft portion 21b in the axial direction. In other words, the thrust plate 59 is a sliding member that supports the thrust load of the crankshaft 21. The oil inlet hole 57 of the thrust plate 59 is a through hole that connects the inside of the sealed container 15 to the inside of the through hole 61 of the sub-shaft plate 63, which is closed by the third cylinder 39C and the thrust plate 59. The oil inlet hole 57 supplies lubricating oil stored in the sealed container 15 to the inside of the through hole 61. The supplied lubricating oil ensures the sliding properties of the area in which the sub-shaft portion 21b slides against the thrust plate 59, and also spreads to the sliding area inside the compression mechanism 19 through the gap Lg and a passage (not shown) provided inside the crankshaft 21.

[0058] Furthermore, the through-hole 61 of the sub-shaft plate 63 is circular in shape. By providing a gap Lg between the inner circumferential surface 61a of the through-hole 61 and the outer circumferential surface 21ba of the sub-shaft portion 21b, a non-contact state between the sub-shaft plate 63 and the sub-shaft portion 21b is ensured. This reliably maintains that the lower end portion 26 does not support the radial load of the sub-shaft portion 21b.

[0059] Furthermore, it is preferable that the lower end portion 26 of the compression mechanism 19 is provided with a third discharge valve mechanism 26a and a discharge chamber 26b for discharging the refrigerant compressed in the cylinder chamber 37 of the third cylinder 39C. In other words, it is preferable that the lower end portion 26 has a third discharge valve mechanism 26a and a discharge chamber 26b for discharging the refrigerant compressed in the cylinder chamber 37 of the third cylinder 39C. By doing so, it is possible to prevent the structure of the intermediate bearing 25 from becoming more complex compared to the case in which the intermediate bearing 25, which requires axial alignment, is provided with a discharge valve mechanism and a discharge chamber for discharging the refrigerant compressed in the cylinder chamber 37 of the third cylinder 39C. In other words, the third discharge valve mechanism 26a and discharge chamber 26b of the lower end portion 26 can be easily configured to discharge the refrigerant compressed in the cylinder chamber 37 of the third cylinder 39C.

[0060] Furthermore, if the lower end portion 26 has a third discharge valve mechanism 26a and a discharge chamber 26b, the third discharge valve mechanism 26a opens a discharge port (not shown) when the pressure difference between the pressure in the cylinder chamber 37 of the third cylinder 39C and the pressure in the discharge chamber 26b reaches a predetermined value due to the compression action of the compression mechanism 19, thereby discharging the compressed refrigerant into the sealed container 15.

[0061] Furthermore, it is preferable that the intermediate bearing 25 is connected to the second suction pipe 51B and has a first refrigerant passage 53 that branches the refrigerant from the second suction pipe 51B to the second cylinder 39B, and a second refrigerant passage 55 that branches the refrigerant from the second suction pipe 51B to the third cylinder 39C. In other words, it is preferable that the second suction pipe 51B passes through the intermediate bearing 25, branches at the intermediate bearing 25, and is connected to the cylinder chamber 37 of the second cylinder 39B and the cylinder chamber 37 of the third cylinder 39C. By doing so, the number of suction pipes 51 is reduced to one compared to the case where two suction pipes 51 are each connected to the cylinder chamber 37 of the second cylinder 39B and the cylinder chamber 37 of the third cylinder 39C. In other words, the manufacturing cost of the compressor 3 is reduced and the manufacturability of the compressor 3 is improved.

[0062] As described above, the compressor 3 and refrigeration cycle device 1 according to this embodiment are equipped with a three-cylinder rotary-type compression mechanism 19 having a lower end portion 26 that supports the thrust load of the crankshaft 21 without supporting the radial load of the sub-shaft portion 21b. Unlike the sub-bearing in conventional three-cylinder rotary-type compressors, the lower end portion 26 does not support the radial load of the sub-shaft portion 21b and does not require axial alignment. In other words, in the compressor 3, it is sufficient to axially align only two bearings, the main bearing 23 and the intermediate bearing 25. Therefore, in the compressor 3, axial alignment of the bearings can be performed easily and with high precision compared to conventional compressors that require axial alignment of three bearings: the main bearing, the intermediate bearing, and the sub-bearing. Thus, although the compressor 3 and refrigeration cycle device 1 are equipped with a three-cylinder rotary-type compression mechanism 19, axial alignment of the two bearings, the main bearing 23 and the intermediate bearing 25, is possible easily and with high precision, and the compressor 3 and refrigeration cycle device 1 can have excellent manufacturability and reliability.

[0063] Furthermore, a three-cylinder rotary compressor is also known in which the crankshaft is supported by two bearings: a main bearing located at the upper end (one end) of the compression mechanism and a sub-bearing located at the lower end (the other end) of the compression mechanism. Unlike this conventional compressor, the compressor 3 of this embodiment supports the crankshaft 21 by two bearings: a main bearing 23 located at the upper end (one end) of the compression mechanism 19, and an intermediate bearing 25 located between the second cylinder 39B and the third cylinder 39C. Therefore, the compressor 3 can shorten the distance between the main bearing 23 and the intermediate bearing 25 compared to the distance between the main bearing and the sub-bearing in a conventional compressor. In other words, the compressor 3 reduces the amount of deflection of the crankshaft 21 between the two bearings, the main bearing 23 and the intermediate bearing 25, compared to a conventional compressor. Generally, when the amount of deflection of the crankshaft increases, extreme pressure acts on the eccentric part, main shaft part, intermediate shaft part and sub-shaft part of the crankshaft, and the reliability of the compressor decreases as these sliding parts seize up. The compressor 3 and refrigeration cycle device 1 of this embodiment reduce the amount of deflection of the crankshaft 21, thereby reducing the extreme pressure on the sliding surfaces of the main bearing 23 and the intermediate bearing 25. As a result, the compressor 3 and refrigeration cycle device 1 can have excellent reliability.

[0064] Furthermore, the compressor 3 and refrigeration cycle device 1 according to this embodiment satisfy the above-mentioned relational equations (1) to (4). As a result, the intermediate bearing 25 can be inserted into the intermediate shaft portion 21c from either the upper end (one end) side of the crankshaft 21 or the lower end (the other end) side of the crankshaft 21. Therefore, the compressor 3 and refrigeration cycle device 1 alleviate the constraints on the assembly of the compression mechanism 19, enabling more flexible assembly of the compression mechanism 19. Consequently, the compressor 3 and refrigeration cycle device 1 can have superior manufacturability.

[0065] Furthermore, the compressor 3 and refrigeration cycle device 1 according to this embodiment satisfy the above-mentioned relational equations (1') to (3'). By doing so, the intermediate bearing 25 can be inserted into the intermediate shaft portion 21c only from the lower end (other end) of the crankshaft 21, while the outer diameter D3 of the third eccentric portion 36C of the crankshaft 21 can be made as small as possible. If the outer diameter D3 of the third eccentric portion 36C can be made small, the diameter of the through hole 25a of the intermediate bearing 25 can also be made small when inserting the intermediate bearing 25 into the crankshaft 21. In other words, the outer diameter Dm of the intermediate shaft portion 21c, which is located inside the through hole 25a of the intermediate bearing 25, can be made small. Generally, reducing the outer diameter of each shaft portion and the outer diameter of the eccentric portion of the crankshaft can reduce sliding losses in each shaft portion and eccentric portion when the compressor is in operation. Therefore, the compressor 3 and the refrigeration cycle device 1 can reduce the sliding losses of the intermediate shaft portion 21c and the third eccentric portion 36C, and have excellent efficiency.

[0066] Furthermore, the compressor 3 and refrigeration cycle device 1 according to this embodiment include a lower end portion 26 having a thrust plate 59 that contacts the end face (lower end face) of the sub-shaft portion 21b of the crankshaft 21 and has an oil inlet hole 57 provided to be aligned with the rotational centerline C of the crankshaft 21, and a sub-shaft plate 63 that has a through hole 61 in which the sub-shaft portion 21b is arranged and is located between the thrust plate 59 and the third cylinder 39C. A gap Lg is provided around the entire circumference between the inner circumferential surface 61a of the through hole 61 and the sub-shaft portion 21b. The thrust plate 59 supports the thrust load of the crankshaft 21. The gap Lg prevents the radial load of the sub-shaft portion 21b from acting on the sub-shaft plate 63. The oil inlet hole 57 supplies lubricating oil stored in the sealed container 15 into the through hole 61. The supplied lubricating oil ensures the sliding surface between the sub-shaft portion 21b and the thrust plate 59, and also spreads to the sliding region inside the compression mechanism 19 through the gap Lg and a passage (not shown) provided inside the crankshaft 21. As a result, the compressor 3 and the refrigeration cycle device 1 can have superior reliability by ensuring sufficient sliding within the compression mechanism 19.

[0067] Furthermore, the compressor 3 and refrigeration cycle device 1 according to this embodiment are equipped with a lower end portion 26 having a third discharge valve mechanism 26a for discharging the refrigerant compressed in the cylinder chamber 37 of the third cylinder 39C, and a discharge chamber 26b. Therefore, the compressor 3 and refrigeration cycle device 1 can prevent the structure of the intermediate bearing 25 from becoming more complex compared to the case where the intermediate bearing 25, which requires axial alignment, is equipped with a discharge valve mechanism and a discharge chamber for discharging the refrigerant compressed in the cylinder chamber 37 of the third cylinder 39C. In other words, the compressor 3 and refrigeration cycle device 1 can have better manufacturability compared to the case where the intermediate bearing 25 is equipped with a discharge valve mechanism and a discharge chamber for discharging the refrigerant compressed in the cylinder chamber 37 of the third cylinder 39C.

[0068] Furthermore, the compressor 3 and refrigeration cycle device 1 according to this embodiment are equipped with an intermediate bearing 25 having a first refrigerant passage 53 connected to the second suction pipe 51B and branching the refrigerant from the second suction pipe 51B to the second cylinder 39B, and a second refrigerant passage 55 branching the refrigerant from the second suction pipe 51B to the third cylinder 39C. The intermediate bearing 25 reduces the number of suction pipes 51 to one compared to the case where two suction pipes 51 are connected to the cylinder chamber 37 of the second cylinder 39B and the cylinder chamber 37 of the third cylinder 39C, respectively. As a result, the compressor 3 and refrigeration cycle device 1 can reduce the number of parts, have advantages in manufacturing costs, and have even better manufacturability.

[0069] Therefore, according to the compressor 3 and refrigeration cycle device 1 of this embodiment, even with a three-cylinder rotary compression mechanism 19, it is possible to easily and accurately align the bearing shaft, and thus it can have excellent manufacturability and reliability.

[0070] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of symbols]

[0071] 1...Refrigeration cycle unit, 3...Rotary compressor (compressor), 5...Radar, 7...Expansion device, 9...Heat absorber, 11...Refrigerant piping, 11b...Discharge pipe, 15...Sealed container, 15a...Body, 15b...Upper end plate, 15c...Lower end plate, 17...Electric motor, 19...Compression mechanism, 21...Crankshaft, 21a...Main shaft section, 21b...Sub-shaft section, 21ba...Outer surface, 21c...Intermediate shaft section, 23...Main bearing, 23a...First discharge valve mechanism, 25...Intermediate bearing, 25a...Through hole, 26...Lower end, 26a...Third discharge valve mechanism, 26b...Discharge chamber, 27...Accumulator, 28...Sealed terminal section, 29...Stator, 31...Rotor, 32...Rotor core, 33...Outlet wire, 34...Fixed Sub-core, 34a, 34b...end face, 35A, 35B...insulating end plate, 36...eccentric part, 36A...first eccentric part, 36B...second eccentric part, 36C...third eccentric part, 37...cylinder chamber, 39...cylinder, 39A...first cylinder, 39B...second cylinder, 39C...third cylinder, 41...roller, 42...blade, 43...partition plate, 43a...second discharge valve mechanism, 43b...discharge chamber, 45...fastening member, 47...discharge muffler, 51...suction pipe, 51A...first suction pipe, 51B...second suction pipe, 53...first refrigerant passage, 55...second refrigerant passage, 57...fuel inlet hole, 59...thrust plate, 61...through hole, 61a...inner circumferential surface, 63...sub-shaft plate.

Claims

1. A cylindrical sealed container, The electric motor is located inside the sealed container, A three-cylinder rotary compression mechanism is provided, which is located within the sealed container and capable of compressing the refrigerant, and comprises a first cylinder, a second cylinder, and a third cylinder, which are spaced apart in order of proximity to the electric motor. A crankshaft is provided which transmits the rotational driving force of the electric motor to the compression mechanism, having a cylindrical main shaft portion located between the electric motor and the first cylinder, a cylindrical intermediate shaft portion located between the second cylinder and the third cylinder, and a cylindrical sub-shaft portion located on the opposite side of the intermediate shaft portion with the third cylinder in between. The compression mechanism is A main bearing located between the electric motor and the first cylinder, which rotatably supports the main shaft portion, An intermediate bearing located between the second cylinder and the third cylinder, which rotatably supports the intermediate shaft portion, A compressor comprising: a lower end portion located on the side further away from the third cylinder as viewed from the second cylinder, which supports the thrust load of the crankshaft.

2. The aforementioned crankshaft is A cylindrical first eccentric portion is disposed within the first cylinder, A cylindrical second eccentric portion is located inside the second cylinder, It has a cylindrical third eccentric portion located inside the third cylinder, The compressor according to claim 1, wherein the following relational equations (1) to (4) are satisfied, given that the outer diameter of the first eccentric portion is D1, the outer diameter of the second eccentric portion is D2, the outer diameter of the third eccentric portion is D3, the eccentricity of the first eccentric portion is E1, the eccentricity of the second eccentric portion is E2, the eccentricity of the third eccentric portion is E3, the outer diameter of the intermediate shaft portion is Dm, the distance between the lower end of the first eccentric portion and the upper end of the second eccentric portion is Lb, and the length of the intermediate bearing in the axial direction is Lm. D1=D2=D3 (1) E1=E2=E3 (2) Dm>(D1 / 2+E1)×2 (3) Lb > Lm (4)

3. The aforementioned crankshaft is A cylindrical first eccentric portion is disposed within the first cylinder, A cylindrical second eccentric portion is located inside the second cylinder, It has a cylindrical third eccentric portion located inside the third cylinder, The compressor according to claim 1, wherein when the outer diameter of the first eccentric portion is D1, the outer diameter of the second eccentric portion is D2, the outer diameter of the third eccentric portion is D3, the eccentricity of the first eccentric portion is E1, the eccentricity of the second eccentric portion is E2, the eccentricity of the second eccentric portion is E3, and the outer diameter of the intermediate shaft portion is Dm, the compressor satisfies the following relational expressions (1') to (3'). D1=D2>D3 (1') E1=E2=E3 (2') Dm>(D3 / 2+E3)×2 (3')

4. The lower end portion is, A thrust plate having an oil supply inlet hole positioned along the rotational centerline of the crankshaft and in contact with the end face of the sub-shaft portion, The sub-shaft plate has a through hole in which the sub-shaft portion is arranged, and is located between the third cylinder and the thrust plate. The compressor according to claim 1, wherein a gap is provided between the inner circumferential surface of the through hole and the sub-shaft portion.

5. The compressor according to claim 1, wherein the lower end portion comprises a discharge valve mechanism for discharging the refrigerant compressed by the third cylinder and a discharge chamber.

6. A first suction pipe that guides the refrigerant into the first cylinder, The device comprises a second suction pipe that guides the refrigerant into the second cylinder and the third cylinder, The compressor according to claim 1, wherein the intermediate bearing is connected to the second suction pipe and has a first refrigerant passage that branches the refrigerant from the second suction pipe to the second cylinder, and a second refrigerant passage that branches the refrigerant from the second suction pipe to the third cylinder.

7. The compressor according to claim 1, Heat sink and Expansion device and Heat absorber and A refrigeration cycle device comprising a compressor, a heat sink, an expansion device, and a heat absorber connected to a refrigerant piping for circulating the refrigerant.

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