Scroll compressor and air conditioner

Abstract

To provide a scroll compressor etc. that has high performance and low cost. [Solution] The scroll compressor 100 comprises a sealed container 1, a frame 23, a fixed scroll 21, an orbiting scroll 22, an electric motor 8, and a crankshaft 3. The crankshaft 3 has an eccentric portion 3b, an intermediate portion 31a, and a small diameter portion 32a, and further comprises a main bearing 4 that rotatably supports the eccentric portion 3b relative to the frame 23, a swivel bearing 5 that rotatably supports the swivel shaft 22c relative to the circumferential surface of the eccentric hole 31b, and an auxiliary bearing 6 that is arranged below the main bearing 4 and rotatably supports the intermediate portion 31a relative to the frame 23, and the step surface 33a abuts against a thrust bearing 23d at the lower end of the frame 23, or a thrust bearing 7 placed on the thrust bearing 23d.

Description

[Technical Field]

[0001] The present disclosure relates to scroll compressors and the like. [Background technology]

[0002] Regarding the structure of a scroll compressor, for example, the technology described in Patent Document 1 is known. That is, Patent Document 1 describes a scroll compressor configured such that an eccentric hole is provided in the upper end of a crankshaft and a scroll pin is fitted into this eccentric hole. The upper end of the crankshaft is journaled on its outer periphery by a main bearing and on its inner periphery by an orbiting bearing. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 2923582 Summary of the Invention [Problem to be solved by the invention]

[0004] In the technology described in Patent Document 1, a separate bearing is provided below the main bearing, but the oil that lubricates this bearing may flow down onto the rotor, stirring up the oil and potentially leaking out of the scroll compressor along with the refrigerant. Furthermore, while there has been a demand in recent years for higher performance and lower costs for scroll compressors, Patent Document 1 does not describe any technology for achieving this.

[0005] Therefore, an object of the present disclosure is to provide a scroll compressor or the like that has high performance and low cost. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems, a scroll compressor according to the present disclosure includes a sealed container, a frame installed inside the sealed container, a fixed scroll having a spiral-shaped fixed wrap, an orbiting scroll having a spiral-shaped orbiting wrap that forms a compression chamber between the fixed wrap and the orbiting wrap, and having an orbiting shaft provided on the opposite side of the orbiting wrap with respect to an end plate, an electric motor having a stator and a rotor, and a crankshaft that is cantilevered inside the frame and rotates integrally with the rotor, and the crankshaft has an eccentric engaging member that engages with the orbiting shaft. a first bearing having an eccentric portion in which a hole is provided, an intermediate portion connected to the lower side of the eccentric portion, and a small diameter portion connected to the lower side of the intermediate portion via a stepped surface and having a diameter shorter than that of the intermediate portion, the first bearing rotatably supporting the eccentric portion relative to the frame, a second bearing rotatably supporting the turning shaft relative to the circumferential surface of the eccentric hole, and a third bearing disposed below the first bearing and rotatably supporting the intermediate portion relative to the frame, the stepped surface abutting against a thrust bearing at the lower end of the frame or abutting against a thrust bearing placed on the thrust bearing The thrust receiving portion or the thrust bearing has a thrust receiving surface that receives an axial force from the step surface, the height position of the thrust receiving surface is higher than the height position of the upper surface of the rotor, and a gap is provided between the thrust receiving surface and the third bearing in the vertical direction. It was decided that. [Effects of the Invention]

[0007] According to the present disclosure, it is possible to provide a scroll compressor and the like that has high performance and low cost. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a vertical cross-sectional view of a scroll compressor according to a first embodiment. [Figure 2] 3 is an explanatory diagram of forces and moments acting in a predetermined manner inside the scroll compressor according to the first embodiment. FIG. [Figure 3] FIG. 2 is an explanatory diagram showing the flow of oil in the scroll compressor according to the first embodiment. [Figure 4] FIG. 4 is a vertical cross-sectional view of a scroll compressor according to a modified example of the first embodiment. [Figure 5] FIG. 10 is a configuration diagram of an air conditioner according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] First Embodiment <Scroll compressor configuration> FIG. 1 is a vertical cross-sectional view of a scroll compressor 100 according to a first embodiment. The scroll compressor 100 shown in Fig. 1 is a device that compresses a gaseous refrigerant. As shown in Fig. 1, the scroll compressor 100 includes a sealed container 1, a compression mechanism 2, a crankshaft 3, a main bearing 4 (first bearing), an orbiting bearing 5 (second bearing), an auxiliary bearing 6 (third bearing), and a thrust bearing 7. In addition to the above-described components, the scroll compressor 100 also includes an electric motor 8, a balance weight 9, an oil return pipe 10, a centrifugal pump 11, a power supply terminal 12, and legs 13.

[0010] The sealed container 1 is a metal container that houses components such as the compression mechanism 2, crankshaft 3, and electric motor 8, and is substantially sealed. Oil is sealed in the sealed container 1 to improve the lubrication of each sliding part, and the oil is stored as an oil reservoir R1 at the bottom of the sealed container 1. The sealed container 1 includes a cylindrical chamber 1a, a lid chamber 1b that closes the upper side of the cylindrical chamber 1a, and a bottom chamber 1c that closes the lower side of the cylindrical chamber 1a.

[0011] As shown in Fig. 1, a suction pipe P1 is inserted into and fixed to the cover chamber 1b of the sealed container 1. The suction pipe P1 is a pipe that guides refrigerant to a suction chamber (not shown) of the compression mechanism 2. A discharge pipe P2 is inserted into and fixed to the cylindrical chamber 1a of the sealed container 1. The discharge pipe P2 is a pipe that guides refrigerant compressed by the compression mechanism 2 to the outside of the scroll compressor 100.

[0012] The compression mechanism 2 is a mechanism that compresses the refrigerant in accordance with the rotation of the crankshaft 3. The compression mechanism 2 includes a fixed scroll 21, an orbiting scroll 22, a frame 23, and an Oldham ring 24, and is disposed in the upper space within the sealed container 1.

[0013] The fixed scroll 21 is a member that forms the compression chamber C1 together with the orbiting scroll 22. The fixed scroll 21 is installed on the upper side of a frame 23 and fixed to the frame 23 with a plurality of bolts. As shown in FIG. 1, the fixed scroll 21 includes a base plate 21a, a support portion 21b, and a fixed wrap 21c, which are integrally formed.

[0014] The base plate 21a is a thick portion having a circular shape in a plan view. The support portion 21b is a cylindrical portion that supports the base plate 21a and is provided on the peripheral edge of the base plate 21a so as to surround the fixed wrap 21c. The annular lower surface of the support portion 21b forms a mirror plate surface that slides between the orbiting scroll 22. The height position of this mirror plate surface is approximately equal to the height position of the tooth tip of the fixed wrap 21c. Furthermore, a plane (not shown) including the mirror plate surface is approximately perpendicular to the central axis of the crankshaft 3. The fixed wrap 21c has a spiral shape and extends downward from the base plate 21a.

[0015] The orbiting scroll 22 is a member that orbits in conjunction with the rotation of the crankshaft 3 and forms a compression chamber C1 between itself and the fixed scroll 21. The orbiting scroll 22 is disposed between the fixed scroll 21 and the frame 23. The orbiting scroll 22 is disposed so as to face the fixed scroll 21 with its central axis being eccentric by a predetermined distance from the central axis of the fixed scroll 21.

[0016] As shown in FIG. 1, the orbiting scroll 22 includes an end plate 22a, an orbiting wrap 22b, and an orbiting shaft 22c, which are integrally formed. The end plate 22a is a portion that slides between itself and the fixed scroll 21 and is disk-shaped. The orbiting wrap 22b is spiral-shaped and extends upward from the end plate 22a. The orbiting shaft 22c is cylindrical and extends downward from the center of the back surface of the end plate 22a. In other words, the orbiting shaft 22c is provided on the opposite side of the end plate 22a from the orbiting wrap 22b. The orbiting shaft 22c is fitted into an eccentric hole 31b of the crankshaft 3.

[0017] A compression chamber C1 is formed between the spiral fixed wrap 21c and the spiral orbiting wrap 22b. The compression chamber C1 is a space for compressing a gaseous refrigerant, and is formed on each of the outer and inner line sides of the orbiting wrap 22b. A discharge port K1 is provided near the center of the base plate 21a of the fixed scroll 21, and guides the refrigerant compressed in the compression chamber C1 to a discharge space C2 above the compression mechanism 2. The refrigerant discharged into the discharge space C2 through this discharge port K1 is guided below the compression mechanism 2 via a predetermined gap between the sealed container 1 and the compression mechanism 2.

[0018] The frame 23 is a member for supporting the fixed scroll 21 and for fixing the main bearing 4 and the sub-bearing 6. The frame 23 has a roughly rotationally symmetric shape and is installed inside the sealed container 1. Specifically, the frame 23 is fixed to the inner circumferential surface of the cylindrical chamber 1a by press fitting or the like. The frame 23 is provided with an insertion hole 23a for inserting the crankshaft 3 therethrough.

[0019] As shown in FIG. 1, the frame 23 has a cylindrical partition wall 23b surrounding the eccentric portion 3b of the crankshaft 3. The partition wall 23b separates a space radially inside from a space radially outside. The partition wall 23b has an annular groove (not shown) recessed downward from its upper end surface. A resin seal ring E1 is installed in this groove. The seal ring E1 is compressed in the vertical direction between the lower surface of the end plate 22a of the orbiting scroll 22 and the wall surface of the groove in the partition wall 23b.

[0020] Furthermore, an oil return hole 23c is provided laterally in the frame 23. The oil return hole 23c is a flow path that guides the oil that has lubricated the main bearing 4, the slewing bearing 5, and the sub-bearing 6 to the oil return pipe 10. The upstream end of the oil return pipe 10 is inserted into the oil return hole 23c.

[0021] Frame 23 also has thrust bearing portion 23d at its lower end. Thrust bearing portion 23d is a portion that receives axial (thrust direction) force from stepped surface 33a of crankshaft 3 via thrust bearing 7, and is annular in plan view. The diameter (inner diameter) of the inner peripheral edge of thrust bearing portion 23d is shorter than the diameter of intermediate portion 31a of crankshaft 3. The inner peripheral edge of thrust bearing portion 23d is also close to the peripheral surface of small diameter portion 32a of crankshaft 3.

[0022] The Oldham ring 24 is a ring-shaped member that receives the eccentric rotation of the orbiting shaft 22c and orbits the orbiting scroll 22 without rotating on its axis. The Oldham ring 24 is installed on the orbiting scroll 22 and the frame 23 in a predetermined manner.

[0023] The crankshaft 3 is a shaft that rotates integrally with the rotor 82 of the electric motor 8 and extends in the vertical direction. As shown in Fig. 1, the crankshaft 3 includes a main shaft portion 3a and an eccentric portion 3b. The main shaft portion 3a is fixed coaxially to the rotor 82 of the electric motor 8 and rotates integrally with the rotor 82. The main shaft portion 3a includes an intermediate portion 31a, a small diameter portion 32a, and a stepped surface 33a.

[0024] The intermediate portion 31a is a portion of the crankshaft 3 that is provided between the eccentric portion 3b and the small diameter portion 32a. The intermediate portion 31a is connected to the lower side of the eccentric portion 3b and is surrounded by the frame 23. The small diameter portion 32a has a diameter shorter than that of the intermediate portion 31a and is connected to the lower side of the intermediate portion 31a via a step surface 33a. Most of the small diameter portion 32a is located outside the frame 23 in the radial direction. However, the upper end of the small diameter portion 32a overlaps with the thrust bearing 7 and the thrust receiving portion 23d of the frame 23 in the radial direction.

[0025] The stepped surface 33a is an annular surface that forms the boundary between the intermediate portion 31a and the small diameter portion 32a. As shown in Fig. 1, the stepped surface 33a abuts on the upper surface of the thrust bearing 7. The surface direction of the stepped surface 33a is approximately perpendicular to the axial direction of the crankshaft 3.

[0026] The eccentric portion 3b extends upward from the main shaft portion 3a and has a cylindrical shape with a bottom that opens upward. As shown in FIG. 1, the eccentric portion 3b has an eccentric hole 31b. The eccentric hole 31b is a hole that fits over the cylindrical revolving shaft 22c and opens upward. The eccentric hole 31b has a circular shape in a plan view, and its central axis is eccentric to a predetermined degree relative to the central axis of the main shaft portion 3a. As the electric motor 8 is driven, the revolving shaft 22c moves eccentrically relative to the main shaft portion 3a. As a result, the revolving scroll 22 orbits eccentrically relative to the fixed scroll 21.

[0027] As shown in Fig. 1, a through-hole 3c through which oil flows is provided in the axial direction inside the crankshaft 3. A horizontal hole 3d is also provided in the crankshaft 3 so as to communicate with the through-hole 3c. Some of the oil flowing through the through-hole 3c is guided to the sub-bearing 6 via the horizontal hole 3d.

[0028] As shown in Fig. 1, a centrifugal pump 11 is installed near the lower end of the crankshaft 3. As the electric motor 8 is driven, oil is sucked up from the oil reservoir R1 through the centrifugal pump 11 and the through-hole 3c in this order. This allows the compression mechanism 2, as well as the main bearing 4, slewing bearing 5, and sub-bearing 6, to be appropriately lubricated.

[0029] 1 supports the eccentric part 3b rotatably relative to the frame 23, and is fixed to the inner peripheral surface of the frame 23 by press-fitting or the like. As such a main bearing 4, for example, a cylindrical sliding bearing is used.

[0030] The slewing bearing 5 (second bearing) rotatably supports the slewing shaft 22c relative to the circumferential surface of the eccentric hole 31b, and is disposed below the main bearing 4 (first bearing). For example, a cylindrical plain bearing is used as the slewing bearing 5. The slewing bearing 5 may be fixed to the circumferential surface of the eccentric hole 31b by press-fitting or the like, or may be fixed to the slewing shaft 22c by press-fitting or the like, either of these.

[0031] In the example of Fig. 1, the installation area of ​​the main bearing 4 in the axial direction and the installation area of ​​the slewing bearing 5 in the axial direction are approximately the same, but this is not limited to this. In other words, it is sufficient that the installation areas of the main bearing 4 and the slewing bearing 5 in the axial direction at least partially overlap. This type of configuration is called a "double bearing structure."

[0032] By adopting a double bearing structure, when a predetermined force due to a gas load acts from the orbiting shaft 22c, the point of action at the orbiting bearing 5 and the point of action at the main bearing 4 are approximately aligned in the axial direction. Therefore, it is possible to suppress the generation of a moment that would tilt the crankshaft 3, and in turn, to suppress one-sided contact of the crankshaft 3. In addition, when the scroll compressor 100 is operated at high speed (for example, 160 [s -1 ] or more), deflection of the crankshaft 3 can be suppressed. Furthermore, by adopting a double bearing structure, the vertical length of the scroll compressor 100 can be shortened, and the scroll compressor 100 can be made more compact, compared to a configuration (not shown) in which an orbiting bearing is arranged above the main bearing.

[0033] The sub-bearing 6 (third bearing) shown in FIG. 1 rotatably supports the middle section 31a of the crankshaft 3 relative to the frame 23, and is fixed by press-fitting or the like into an insertion hole 23a in the lower part of the frame 23. The height position of the sub-bearing 6 is higher than the height position of the electric motor 8. For example, a cylindrical plain bearing is used as this type of sub-bearing 6. Using plain bearings as the main bearing 4, slewing bearing 5, and sub-bearing 6 not only extends the life of each bearing, but also ensures durability during high-speed operation.

[0034] The inner diameter of the sub-bearing 6 is shorter than the inner diameter of the main bearing 4. Because the inner diameter of the sub-bearing 6 is relatively short, its sliding distance (the circumferential length of the sub-bearing 6) is also short. As a result, sliding loss of the sub-bearing 6 is reduced, and wear of the sub-bearing 6 is suppressed.

[0035] The thrust bearing 7 is a bearing that receives an axial (thrust direction) load from the crankshaft 3 and has a thin, annular shape. As shown in FIG. 1, the thrust bearing 7 is mounted on the thrust bearing portion 23d of the frame 23. The thrust bearing 7 has a thrust bearing surface (i.e., the upper surface of the thrust bearing 7; reference numeral is not shown) that receives an axial force from the stepped surface 33a of the crankshaft 3. The thrust bearing 7 is also disposed below the sub-bearing 6. The thrust bearing 7 is disposed slightly spaced apart from the sub-bearing 6 in the up-down direction.

[0036] As shown in FIG. 1, the crankshaft 3 is cantilevered within the frame 23. Here, "cantilevered" means that the upper part of the crankshaft 3 is journaled within the frame 23 without the need for a sub-frame (not shown) to journal the lower part of the crankshaft 3. In the example of FIG. 1, the crankshaft 3 is journaled within the frame 23 by a main bearing 4 and a sub-bearing 6. This cantilevered support structure eliminates the need for a separate sub-frame (not shown), thereby reducing costs. Furthermore, as will be described later, this also simplifies the assembly process.

[0037] The electric motor 8 is a drive source that rotates the crankshaft 3. For example, a permanent magnet synchronous motor is used as the electric motor 8, but other types of motors may also be used. The electric motor 8 includes a stator 81 and a rotor 82, and is disposed below the compression mechanism 2.

[0038] The stator 81 has a stator core 81a and windings 81b, and is fixed to the inner circumferential surface of the cylindrical chamber 1a. The stator core 81a is a cylindrical member configured by stacking electromagnetic steel sheets in the axial direction. The windings 81b are wound around the stator core 81a. When a predetermined current flows through the windings 81b, magnetic attraction and repulsion forces are generated between the stator 81 and the rotor 82, causing the rotor 82 to rotate. For example, by using an interior permanent magnet synchronous motor as the electric motor 8, the rotor 82 can be rotated at high speed.

[0039] The rotor 82 rotates around the central axis of the crankshaft 3 and is disposed radially inside the stator 81. The rotor 82 has, for example, a cylindrical iron core 82a with multiple permanent magnets (not shown) embedded in it. The crankshaft 3 is fixed to the rotor 82 so as to be coaxial with the central axis of the rotor 82.

[0040] The balance weight 9 is a member for suppressing vibration of the scroll compressor 100. In the example of Fig. 1, the balance weight 9 is installed below the rotor 82. Note that the number and installation locations of the balance weights can be changed as appropriate.

[0041] The oil return pipe 10 is a pipe for returning the oil that has lubricated the main bearing 4, the slewing bearing 5, and the auxiliary bearing 6 to the oil reservoir R1. The oil return pipe 10 has an inverted L-shape in side view, and is inserted into the oil return hole 23c of the frame 23 as described above.

[0042] The centrifugal pump 11 is a pump for sucking up oil from an oil reservoir R1 at the bottom of the sealed container 1, and is installed at the lower end of the crankshaft 3. In the example of Fig. 1, the centrifugal pump 11 is hollow, but this is not limiting. For example, a spiral metal piece (not shown) may be installed inside the centrifugal pump 11.

[0043] Power supply terminal 12 is a terminal used to supply power to electric motor 8. Power supply terminal 12 is installed in cylindrical chamber 1a and electrically connected to winding 81b of electric motor 8. Multiple legs 13 are members that support sealed container 1 and are installed in bottom chamber 1c. Note that the configuration shown in FIG. 1 is an example and is not limited to this.

[0044] <About the cantilever support structure> As described above, the crankshaft 3 is supported in a cantilever manner inside the frame 23 by the main bearing 4 and the auxiliary bearing 6. As a result, there is no need to separately provide a sub-frame (not shown) for pivotally supporting the lower portion of the crankshaft 3. If a sub-frame is provided, a process for aligning the axial centers between the frame 23 and the sub-frame and keeping the coaxiality within a predetermined range is performed during the assembly stage. However, even if an attempt is made to align the axial centers of the frame 23 and the sub-frame, it is difficult to improve the coaxiality during the assembly of the two members, and due to the influence of welding deformation, there is a possibility that the error of the axial center may increase as a result.

[0045] On the other hand, in the present embodiment, since there is no particular need to provide a sub-frame (not shown), the material cost can be reduced, and in addition, the assembly process of the sub-frame can be omitted to improve productivity. In addition, compared with the case where an auxiliary bearing is provided in the sub-frame, the vertical distance between the main bearing 4 and the auxiliary bearing 6 is shortened, but since the axial center is accurately machined so as to coincide during the machining of the single member of the frame 23, the coaxiality can be significantly improved compared with the case of aligning the axial centers between a plurality of members. As a result, the inclination of the crankshaft 3 can be suppressed, and thus, the wobbling and single-sided contact of the crankshaft 3 can be suppressed. [[ID=J6]]

[0046] It is preferable that the axial length L1 of the main bearing 4 (first bearing) and the vertical distance L2 from the upper end of the main bearing 4 to the lower end of the auxiliary bearing 6 (third bearing) satisfy the following relationship of formula (1).

[0047] 2×L1 < L2 < 5×L1 ···(1)

[0048] By making the above-mentioned distance L2 longer than twice the length L1 of the main bearing 4 (2×L1 < L2), it is possible to suppress the inclination of the crankshaft 3 during the driving of the electric motor 8. Therefore, the wobbling and single-sided contact of the crankshaft 3 can be suppressed. Further, by making the above-mentioned distance L2 shorter than five times the length L1 of the main bearing 4 (L2 < 5×L1), the vertical length of the scroll compressor 100 can be shortened, and its miniaturization can be achieved.

[0049] FIG. 2 is an explanatory diagram of forces and moments acting in a predetermined manner inside the scroll compressor 100. The gas load F1 shown in FIG. 2 is a radial load acting on the compression mechanism 2 as the refrigerant is compressed. The load F2 is a radial load acting on the Oldham ring 24 as the orbiting scroll 22 moves. The resistance F3 is a radial resistance acting on the orbiting shaft 22c from the orbiting bearing 5. Another resistance F4 is a resistance acting on the thrust reference point T1 of the crankshaft 3 from the sub-bearing 6, etc. The thrust reference point T1 is the point where the central axis of the crankshaft 3 intersects with a plane (not shown) including the upper surface of the thrust bearing 7. The centrifugal force F5 shown in FIG. 2 is a radial centrifugal force acting on the balance weight 9.

[0050] In the example of FIG. 2, gas load F1, load F2, and centrifugal force F5 act in one radial direction (toward the left on the page). The remaining drag forces F3 and F4 act in the other radial direction (toward the right on the page). Moment M1 shown in FIG. 2 is a moment generated around thrust reference point T1 by gas load F1 and load F2. Another moment M2 is a moment generated around thrust reference point T1 by drag force F3 and centrifugal force F5. In the design stage of the scroll compressor 100, the design is performed so that moments M1 and M2 around thrust reference point T1 cancel each other out.

[0051] However, when operating at high speed (for example, 160 [s -1 ] or higher), the centrifugal force of the balance weight 9 attached to the rotor 82 may cause the crankshaft 3 to swing slightly with the rotor 82 as the point of action.

[0052] Therefore, in the present embodiment, the thrust reference point T1 is made as close as possible to the rotor 82 in the vertical direction. Specifically, the vertical distance L3 (see FIG. 1) from the upper surface (thrust receiving surface) of the thrust bearing 7 to the upper surface of the rotor 82 is preferably shorter than the vertical distance L4 (see FIG. 1) from the upper surface (thrust receiving surface) of the thrust bearing 7 to the lower end of the main bearing 4 (first bearing) (L3 < L4). As a result, the deviation of the balance (cancellation of the moments M1 and M2 in FIG. 2) during high-speed operation is reduced, so that the wobbling of the crankshaft 3 can be suppressed.

[0053] Further, the thrust bearing 7 is provided at a location (the lower end of the frame 23) axially separated from the swivel shaft 22c on which a large gas load acts. As a result, even when the crankshaft 3 is slightly inclined, it is possible to suppress a large force from acting on the thrust bearing 7 from the stepped surface 33a, and thus, it is possible to suppress wear and damage associated with single-sided contact.

[0054] FIG. 3 is an explanatory diagram showing the oil flow in the scroll compressor 100. Note that the dashed arrows shown in FIG. 3 indicate the oil flow. The oil sucked up by the centrifugal pump 11 along with the drive of the motor 8 rises through the through-hole 3c of the crankshaft 3, and a part of it is guided to the auxiliary bearing 6 through the lateral hole 3d. The oil lubricating the auxiliary bearing 6 is guided to the oil return pipe 10 so as to be entrained in the oil flow (the oil flow lubricating the main bearing 4 and the swivel bearing 5 and heading toward the oil return pipe 10) through the oil return hole 23c. Then, the oil flows down inside the oil return pipe 10 and is returned to the oil sump R1.

[0055] Also, a part of the oil rising through the through-hole 3c rises through a groove (not shown) between the peripheral surface of the swivel shaft 22c and the swivel bearing 5 to lubricate the swivel bearing 5. Further, this oil descends through a groove (not shown) between the outer peripheral surface of the eccentric portion 3b and the main bearing 4 to lubricate the main bearing 4. The oil lubricating the main bearing 4 is returned to the oil sump R1 through the oil return pipe 10.

[0056] The remainder of the oil that has risen through the through hole 3c is guided to the oil groove G1 on the end plate surface of the fixed scroll 21 via an oil supply passage (not shown) inside the orbiting scroll 22. The oil guided to the oil groove G1 is used for sealing and lubricating the compression chamber C1, and then is guided to the back pressure chamber (not shown).

[0057] As described above, in this embodiment, the thrust bearing 7 is provided below the auxiliary bearing 6. Furthermore, a downward load acts on the thrust bearing 7 from the crankshaft 3. As a result, the stepped surface 33a of the crankshaft 3 and the upper surface of the thrust bearing 7 come into close contact with each other. Therefore, the oil that lubricates the auxiliary bearing 6 rarely drips onto the rotor 82. In other words, the oil is hardly agitated by the rotating rotor 82, which prevents oil from leaking out through the discharge pipe P2.

[0058] <Effects> According to the first embodiment, a double bearing structure is adopted in which the main bearing 4 and the orbiting bearing 5 overlap in the radial direction, which makes it possible to suppress the generation of a moment that would tilt the crankshaft 3. Therefore, it is possible to suppress deflection and uneven contact of the crankshaft 3 even during high-speed operation. Furthermore, the double bearing structure makes it possible to shorten the vertical length of the scroll compressor 100, thereby making it more compact.

[0059] In addition, in this embodiment, because the crankshaft 3 is supported at one end using a cantilever support structure, there is no particular need to provide a separate subframe (not shown) to support the lower part of the crankshaft 3. This reduces material costs, simplifies the assembly process, and reduces costs. Furthermore, by omitting the subframe, the concentricity between the main bearing 4 and the sub-bearing 6 is significantly improved, which, combined with the double bearing structure described above, helps to suppress deflection of the crankshaft 3.

[0060] Additionally, a thrust bearing 7 is disposed below the sub-bearing 6, and the stepped surface 33a of the crankshaft 3 abuts against this thrust bearing 7. Therefore, the oil that lubricates the sub-bearing 6 hardly drips onto the rotor 82, which prevents the oil from being agitated by the rotation of the rotor 82. This prevents oil from leaking out via the discharge pipe P2.

[0061] Also, during high-speed operation (for example, 160 [s -1 Even if a moment that tilts the crankshaft 3 occurs during rotation (during operation at a rotational speed of 100 rpm or higher), the thrust bearing 7 is disposed close to the rotor 82, so that whirling or uneven contact of the crankshaft 3 can be suppressed. In this way, by expanding the capacity range of the scroll compressor 100 through miniaturization and higher speed, it is possible to reduce the number of scroll compressors 100 installed in, for example, a multi-air conditioner for a building, thereby achieving cost reduction. In this way, according to the first embodiment, it is possible to provide a scroll compressor 100 that achieves high performance and low cost.

[0062] <Modification of the First Embodiment> FIG. 4 is a vertical cross-sectional view of a scroll compressor 100A according to a modified example of the first embodiment. The scroll compressor 100A shown in Fig. 4 has a configuration in which the thrust bearing 7 (see Fig. 1) is omitted from the first embodiment. In this configuration, the step surface 33a of the crankshaft 3 abuts against the thrust receiving portion 23d at the lower end of the frame 23. The thrust receiving portion 23d has a thrust receiving surface (the upper surface of the thrust receiving portion 23d, no reference numeral is shown) that receives an axial force from the step surface 33a.

[0063] As shown in Fig. 4, it is preferable that the vertical distance L3 from the thrust receiving surface (upper surface) of the thrust receiving portion 23d to the upper surface of the rotor 82 is shorter than the vertical distance L4 from the upper surface of the thrust receiving portion 23d to the lower end of the main bearing 4 (first bearing). This reduces imbalance (cancellation of moments) during high-speed operation and suppresses whirling of the crankshaft 3. Furthermore, since there is no particular need to provide a thrust bearing, the configuration can be simplified and costs can be reduced.

[0064] Second Embodiment In the second embodiment, an air conditioner W1 (see FIG. 5) including a scroll compressor 100 (see FIGS. 1 and 5) having the configuration described in the first embodiment will be described.

[0065] FIG. 5 is a configuration diagram of an air conditioner W1 according to the second embodiment. The solid arrows in FIG. 5 indicate the flow of the refrigerant in the heating cycle. On the other hand, the dashed arrows in FIG. 5 indicate the flow of the refrigerant in the cooling cycle. The air conditioner W1 is a device that performs air conditioning such as cooling operation and heating operation. As shown in Fig. 5, the air conditioner W1 includes a scroll compressor 100, an outdoor heat exchanger 71, an outdoor fan 72, an expansion valve 73, a four-way valve 74, an indoor heat exchanger 75, and an indoor fan 76.

[0066] 5, the scroll compressor 100, the outdoor heat exchanger 71, the outdoor fan 72, the expansion valve 73, and the four-way valve 74 are provided in the outdoor unit U1, while the indoor heat exchanger 75 and the indoor fan 76 are provided in the indoor unit U2.

[0067] The scroll compressor 100 is a device that compresses refrigerant gas, and has a configuration similar to that of the first embodiment (see FIG. 1). The outdoor heat exchanger 71 is a heat exchanger in which heat exchange occurs between the refrigerant flowing through its heat transfer tubes (not shown) and the outside air sent in from the outdoor fan 72. The outdoor fan 72 is a fan that sends the outside air to the outdoor heat exchanger 71. The outdoor fan 72 is provided with an outdoor fan motor 72a that serves as a drive source, and is installed near the outdoor heat exchanger 71.

[0068] The indoor heat exchanger 75 is a heat exchanger in which heat is exchanged between the refrigerant flowing through its heat transfer pipes (not shown) and the indoor air (air in the air-conditioned room) sent in from the indoor fan 76. The indoor fan 76 is a fan that sends the indoor air to the indoor heat exchanger 75. The indoor fan 76 is provided with an indoor fan motor 76a that serves as a drive source, and is installed near the indoor heat exchanger 75.

[0069] The expansion valve 73 is a valve that reduces the pressure of the refrigerant condensed in the "condenser" (one of the outdoor heat exchanger 71 and the indoor heat exchanger 75). The refrigerant reduced in pressure by the expansion valve 73 is introduced to the "evaporator" (the other of the outdoor heat exchanger 71 and the indoor heat exchanger 75).

[0070] The four-way valve 74 is a valve that switches the refrigerant flow path depending on the operation mode of the air conditioner W1. For example, during cooling operation (see the dashed arrow in FIG. 5), the refrigerant circulates sequentially through the scroll compressor 100, the outdoor heat exchanger 71 (condenser), the expansion valve 73, and the indoor heat exchanger 75 (evaporator). During heating operation (see the solid arrow in FIG. 5), the refrigerant circulates sequentially through the scroll compressor 100, the indoor heat exchanger 75 (condenser), the expansion valve 73, and the outdoor heat exchanger 71 (evaporator).

[0071] <Effects> According to the second embodiment, the air conditioner W1 is equipped with a low-cost, highly efficient scroll compressor 100, so that the air conditioner W1 as a whole can be made less expensive and more efficient.

[0072] <<Variations>> The scroll compressor 100 and the air conditioner W1 according to the present disclosure have been described above in relation to the various embodiments, but they are not limited to these descriptions and can be modified in various ways. For example, in the first embodiment, the case where the oil return pipe 10 (see FIG. 1) is provided has been described, but the oil return pipe 10 may be omitted as appropriate. In the first embodiment, the centrifugal pump 11 (see FIG. 1) is provided, but the present invention is not limited to this. For example, instead of the centrifugal pump 11, another type of pump may be used.

[0073] In the first embodiment, a cylindrical sliding bearing is used as the main bearing 4, the slewing bearing 5, and the auxiliary bearing 6, but this is not limiting. For example, roller bearings or ball bearings can also be used as the main bearing 4, the slewing bearing 5, and the auxiliary bearing 6. In the first embodiment, a permanent magnet is embedded in the iron core 82a (see FIG. 1) of the rotor 82 (see FIG. 1), but this is not limiting. For example, the rotor 82 may have a configuration in which a permanent magnet is not embedded in the iron core 82a.

[0074] The air conditioner W1 (see FIG. 5) described in the second embodiment can be applied to various types of air conditioners, such as multi-air conditioners for buildings, package air conditioners, and room air conditioners. The second embodiment describes the air conditioner W1 equipped with the scroll compressor 100, but the present invention is not limited to this. For example, the second embodiment can also be applied to other refrigeration cycle devices, such as freezers, hot water heaters, air-conditioning hot water heaters, chillers, and refrigerators.

[0075] Furthermore, in the second embodiment, the air conditioner W1 (see FIG. 5) is described as being equipped with a four-way valve 74, but this is not limiting. That is, the four-way valve 74 may be omitted, and the air conditioner may be dedicated to cooling or heating. In the first embodiment, the scroll compressor 100 is described as being installed vertically, but this is not limiting. For example, the scroll compressor 100 may be installed horizontally or obliquely. In this case, the side of the crankshaft 3 on which the eccentric portion 3b is provided is considered to be the "upper side," and the side on which the centrifugal pump 11 is installed is considered to be the "lower side."

[0076] Furthermore, each embodiment has been described in detail to clearly explain the present disclosure, and is not necessarily limited to having all of the configurations described. Furthermore, part of the configuration of each embodiment can be appropriately added to, deleted from, or replaced with other configurations. Furthermore, the mechanisms and configurations described above are those that are considered necessary for the explanation, and do not necessarily represent all mechanisms and configurations of the product. [Explanation of symbols]

[0077] 1. Airtight container 2 Compression mechanism 3 crankshaft 3a Main shaft part 3b Eccentric part 4 Main bearing (first bearing) 5. Slewing bearing (second bearing) 6 Sub-bearing (third bearing) 7 Thrust bearing 8 Electric motor 21 Fixed Scroll 21c fixed wrap 22 Swivel Scroll 22a Headboard 22b Circling Wrap 22c Pivot 23 frames 23d Thrust receiving part 31a middle part 31b Eccentric hole 32a Small diameter section 33a Step surface 71 Outdoor heat exchanger 72 Outdoor fan 73 Expansion valve 74 Four-way valve 75 Indoor heat exchanger 76 Indoor fan 81 Stator 82 rotor 82a Iron core 100,100A scroll compressor C1 compression chamber W1 Air Conditioner

Claims

1. A sealed container and a frame installed inside the sealed container; a fixed scroll having a spiral-shaped fixed wrap; an orbiting scroll having a spiral orbiting wrap that forms a compression chamber between itself and the fixed wrap, and having an orbiting shaft that is provided on the opposite side of the orbiting wrap with respect to the end plate; an electric motor having a stator and a rotor; a crankshaft that is cantilevered inside the frame and rotates integrally with the rotor, the crankshaft has an eccentric portion provided with an eccentric hole that fits onto the rotary shaft, an intermediate portion connected to a lower side of the eccentric portion, and a small diameter portion connected to the lower side of the intermediate portion via a stepped surface and having a diameter shorter than that of the intermediate portion, a first bearing that rotatably supports the eccentric portion relative to the frame; a second bearing that rotatably supports the pivot shaft relative to a peripheral surface of the eccentric hole; a third bearing disposed below the first bearing and supporting the intermediate portion rotatably relative to the frame, the step surface abuts against a thrust receiving portion at a lower end of the frame, or abuts against a thrust bearing placed on the thrust receiving portion, the thrust receiving portion or the thrust bearing has a thrust receiving surface that receives an axial force from the step surface, a height position of the thrust receiving surface is higher than a height position of an upper surface of the rotor; a vertical gap is provided between the thrust receiving surface and the third bearing.

2. The axial length L1 of the first bearing and the vertical distance L2 from the upper end of the first bearing to the lower end of the third bearing have the relationship 2×L1<L2<5×L1.

2. The scroll compressor according to claim 1,

3. The vertical distance from the thrust bearing surface to the upper surface of the rotor is shorter than the vertical distance from the thrust bearing surface to the lower end of the first bearing.

2. The scroll compressor according to claim 1,

4. The first bearing, the second bearing, and the third bearing are each a cylindrical sliding bearing.

2. The scroll compressor according to claim 1,

5. A permanent magnet is embedded in the rotor core.

2. The scroll compressor according to claim 1,

6. An air conditioner comprising: the scroll compressor according to any one of claims 1 to 5; an outdoor heat exchanger; an expansion valve; and an indoor heat exchanger.

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