Compressor

Abstract

This compressor comprises a rotating shaft (14), a compression part (20), and at least one sliding bearing part (36). The rotating shaft has at least one journal part (141a) and extends in an axial direction (Da). The compression part compresses the fluid as the rotating shaft rotates. The journal part has one end portion (361) provided on one side in the axial direction, the journal part is inserted, the journal part is supported so as to be relatively rotatable, and a radial load (Fa) is received from the journal part. The journal part has: a maximum diameter portion (141d) having a maximum diameter; and a crowning portion (141g) which is provided on one side in the axial direction with respect to the maximum diameter portion, faces a radial direction (D1r) of the journal part with respect to the one end portion, and continuously decreases in diameter toward the one side in the axial direction. The crowning portion has a curved outer peripheral surface (141h) continuously connected to an outer peripheral surface (141e) of the maximum diameter portion while curving in a longitudinal cross-section including an axial center (Ca) of the journal part.

Description

Compressor CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Japanese Patent Application No. 2023-147718, filed on September 12, 2023, the contents of which are incorporated herein by reference.

[0002] The present disclosure relates to a compressor for compressing a fluid.

[0003] Patent Document 1 describes a compressor that compresses a refrigerant. The compressor in Patent Document 1 is a scroll-type compressor that includes a compression mechanism composed of a fixed scroll and a movable scroll that compresses the refrigerant, and a main shaft that is connected to the movable scroll and serves as a rotating shaft for orbiting the movable scroll. In the compressor in Patent Document 1, the bearing clearance formed between the main shaft and a main bearing that rotatably supports the main shaft is not constant in the axial direction due to bending of the main shaft under load, and is smallest at the upper end of the main bearing. Therefore, a tapered crowning is formed on the surface of the main shaft corresponding to the upper end of the main bearing. In addition, a similar crowning is formed on the eccentric shaft portion inserted into the movable scroll.

[0004] Japanese Patent Application Laid-Open No. 2002-147354

[0005] Patent Document 1 states that even if a moment is applied to the main shaft due to the load acting on the movable scroll, causing deflection or tilt within the main bearing, a relief is formed by the crowning of the shaft surface, making it possible to maintain a bearing clearance. Patent Document 1 also states that the contact stress with the main shaft at the upper end of the main bearing is reduced, preventing the area near the upper end of the main bearing from coming into direct contact with the main shaft and causing surface damage, and that a fluid lubrication state can be maintained between the main shaft and the main bearing.

[0006] However, with recent changes in product usage, it is necessary to assume that shaft deflection in response to compressive loads will vary over a wide range. Furthermore, when variations in compressor manufacturing are also taken into account, it is difficult to find the appropriate taper angle for the crowning formed on the main shaft.

[0007] For example, if the taper angle of the crowning is excessive or insufficient relative to the tilt of the main shaft within the main bearing caused by bending of the main shaft, the bearing clearance between the main shaft and the main bearing will be locally smaller than necessary at one end or the other of the crowning, resulting in a phenomenon of uneven contact. If this uneven contact occurs between the main shaft and the main bearing, the formation of an oil film between the main shaft and the main bearing will be insufficient, leading to increased sliding loss and wear. The inventors discovered the above as a result of detailed studies.

[0008] In view of the above, an object of the present disclosure is to provide a compressor that can stably maintain a bearing gap that forms an oil film between the journal portion and the plain bearing portion, even if the inclination angle of the journal portion of the rotating shaft relative to the plain bearing portion varies with changes in the load on the rotating shaft.

[0009] In order to achieve the above object, a compressor according to one aspect of the present disclosure comprises: a rotating shaft having at least one journal portion and extending in the axial direction; a compression portion that compresses a fluid as the rotating shaft rotates; and at least one plain bearing portion having one end portion provided on one axial side, into which the journal portion is inserted, supporting the journal portion so that it can rotate relative to the journal portion, and receiving a radial load from the journal portion, wherein the journal portion has a maximum diameter portion having the largest diameter of the journal portion, and a crowning portion provided on one axial side of the maximum diameter portion, radially opposing the journal portion from the one end portion, and having a diameter that continuously decreases towards one axial side, wherein the crowning portion has a curved outer peripheral surface that is curved in a vertical cross section including the axis of the journal portion and is continuous with the outer peripheral surface of the maximum diameter portion, and wherein the journal portion is inclined relative to the plain bearing portion, and the curved outer peripheral surface receives the reaction force of the plain bearing portion that resists the radial load.

[0010] In this way, even if the journal is slightly tilted relative to the plain bearing, the bearing gap that forms the oil film between the journal and the plain bearing is formed between the inner bearing surface of the plain bearing and the curved outer peripheral surface of the journal. Therefore, even if the rotating shaft is bent or tilted, for example, the bearing gap is unlikely to change. In other words, even if the inclination angle of the journal relative to the plain bearing fluctuates due to changes in the load on the rotating shaft, the bearing gap between the journal and the plain bearing can be stably maintained. As a result, the lubrication state between the journal and the plain bearing is unlikely to fluctuate, making it possible to prevent excessive contact pressure on the bearing surface.

[0011] In addition, in each section of the application documents, each element may be assigned a reference number in parentheses. In this case, the reference number merely indicates an example of the correspondence between the element and the specific configuration described in the embodiment described below. Therefore, the present disclosure is not limited in any way by the description of the reference number.

[0012] 3A is a diagram showing a schematic representation of a radial force acting on a rotating shaft in a general scroll compressor and bending deformation of the rotating shaft caused by the radial force. 3B is a diagram showing a schematic representation of bending deformation of the rotating shaft caused by compression of a fluid in a general scroll compressor and a plurality of bearings that apply a radial force to the rotating shaft. 3C is a diagram showing an ideal case in which the main bearing supporting the main shaft of the rotating shaft is free from bending and tilting in a general scroll compressor. 3D is a diagram showing a case in which the main shaft is tilted to a certain extent from the state shown in FIG. 3A, and corresponds to FIG. 3A. 3D is a diagram showing a case in which the main shaft is further tilted from the state shown in FIG. 3B, and corresponds to FIG. 3A. 3E is a diagram showing a case in which the main shaft is tilted in the compressor of Patent Document 1, and the contact angle of the main shaft with respect to the bearing surface of the main bearing is the same or substantially the same as the gradient angle of the crowning of the main shaft. 5A and 5B are diagrams corresponding to FIG. 4A and are schematic diagrams illustrating a case where the main shaft portion in the compressor of Patent Document 1 is inclined and the contact angle of the main shaft portion is smaller than the gradient angle of the crowning.

[0023] FIG. 5B is a diagram corresponding to FIG. 4A and is schematic diagrams illustrating a case where the main shaft portion in the compressor of Patent Document 1 is inclined and the contact angle of the main shaft portion is larger than the gradient angle of the crowning.

[0024] FIG. 5C is a diagram illustrating a schematic configuration of a compressor of a first embodiment, and is a cross-sectional view obtained by cutting the compressor at a cross section including the main shaft center of the compressor and along the vertical direction.

[0025] FIG. 5D is a partially enlarged view showing an enlarged portion VI of FIG. 5.

[0026] FIG. 5E is a partially enlarged view showing an enlarged portion VII of FIG. 5.

[0027] FIG. 5F is a diagram illustrating a rotating shaft provided in the compressor of the first embodiment alone.

[0028] FIG. 5G is a diagram illustrating a bending deformation occurring in the rotating shaft due to compression of a refrigerant, a radial load exerted by the rotating shaft on a bearing portion, and a reaction force against the radial load in the compressor of the first embodiment. 10A is a cross-sectional view showing a state in which the main journal portion of the rotating shaft is tilted to a certain extent relative to the main bearing portion due to bending deformation of the rotating shaft in the first embodiment. 10B is a diagram showing a contact state between the main journal portion and the main bearing portion at the same tilt as in FIG. 10A, but in a deformed shape. 10C is a partially enlarged view showing an enlarged portion of portion XI in FIG. 10A, which is a diagram showing an enlarged schematic view of a bearing gap that forms an oil film between the curved outer peripheral surface of the main journal portion and the main bearing surface.10B. 12A is a cross-sectional view showing a state in which the inclination angle of the main journal portion relative to the main bearing portion is smaller than that of FIG. 10A in the first embodiment, and corresponds to FIG. 10A. 12B is a deformed view showing a contact state between the main journal portion and the main bearing portion, which has the same inclination as that of FIG. 12A, and corresponds to FIG. 10B. 13A is a cross-sectional view showing a state in which the inclination angle of the main journal portion relative to the main bearing portion is larger than that of FIG. 10A in the first embodiment, and corresponds to FIG. 10A. 13B is a deformed view showing a contact state between the main journal portion and the main bearing portion, which has the same inclination as that of FIG. 13A, and corresponds to FIG. 10B. 13B is a graph showing the results of a computer simulation in the first embodiment, illustrating the relationship between the ratio of the axial length of the curved range of the main journal portion divided by the bearing length of the main bearing portion, the surface pressure generated on the main bearing surface, and the minimum oil film thickness formed in the bearing gap. 13C is a view showing a rotating shaft of a compressor of a second embodiment, and corresponds to FIG. 8. 16 is a diagram illustrating a rotating shaft and peripheral parts of the rotating shaft in a third embodiment, the diagram corresponding to FIG. 8. FIG. 17 is a diagram illustrating a posture of a rotating shaft of a compressor when the rotating shaft has high rigidity and does not bend. FIG. 18 is a diagram illustrating a rotating shaft and peripheral parts of the rotating shaft in a modified example of the third embodiment, the diagram corresponding to FIG.

[0013] (Description of the Prior Art) Electric compressors equipped with electric motors have been known for some time. These compressors include reciprocating, rotary, and scroll compressors, each with a compression section that compresses a fluid. In all types of compressors, the radial force of the rotating shaft that drives the compression section is supported by a journal bearing. This journal bearing is also called a radial bearing. Here, we will explain the prior art using a scroll compressor as an example. In various types of compressors, the radial force of the rotating shaft that drives the compression section (i.e., the radial load) is primarily supported by a plain bearing or a rolling bearing. In particular, in scroll compressors that use plain bearings to support the radial load, the compression section side of the rotating shaft is supported in a cantilevered manner. A moment due to the radial force caused by the compressive load of the compression section acts on the rotating shaft, deflecting it and affecting the lubrication of the plain bearing.

[0014] This will be described in detail with reference to Figures 1 and 2. As shown in Figures 1 and 2, the rotating shaft 70 of the compressor has a main shaft portion 701 arranged coaxially with the rotor of the electric motor 71, and an eccentric shaft portion 702 connected to the movable scroll of the compressor and eccentric with respect to the main shaft portion 701. A compressive load and the like generated as the refrigerant is compressed acts on the movable scroll of the compressor. A radial compressive load Fpr, which is a radial force acting on the eccentric shaft portion 702 due to the compressive load and the like, is transmitted to the main shaft portion 701 via the eccentric shaft portion 702 of the rotating shaft 70. The main shaft portion 701 of the rotating shaft 70 is supported by a main bearing portion 731 formed in a main bearing support member 73 and a sub-bearing portion 741 formed in a sub-bearing support member 74 arranged with the electric motor 71 sandwiched between the main bearing portion 731 and the sub-bearing portion 741. In FIG. 1, the reaction force Far of the main bearing portion 731 and the reaction force Fbr of the sub-bearing portion 741 in the radial direction, which are generated by the radial compressive load Fpr, are respectively indicated by arrows.

[0015] In this way, the radial compressive load Fpr caused by the compressive load or the like acts on the eccentric shaft portion 702 of the rotating shaft 70, and is supported in a cantilever structure by the main bearing portion 731 and the sub-bearing portion 741 provided on either side of the electric motor 71. As a result, the main shaft portion 701 of the rotating shaft 70 undergoes bending deformation between the main bearing portion 731 and the sub-bearing portion 741. Note that in Figures 1 and 2 and the schematic diagrams described below, the shapes of the illustrated components are appropriately exaggerated to make the illustrations easier to understand.

[0016] In recent years, the main use of on-board compressors for compressing refrigerants in engine-driven vehicles has been to cool and heat the passenger compartment. In contrast, in hybrid vehicles and electric vehicles that run on both an engine and a traction motor, compressors are expected to be used for equipment cooling and motor cooling as well, and there is a demand for compressors with higher capacity.

[0017] For example, increasing the rotation speed of the compressor is conceivable as a method for increasing the capacity of the compressor without changing its physical size, but in that case, the centrifugal force acting on each component also increases, which leads to deflection of main shaft portion 701. Furthermore, if an attempt is made to increase the capacity of the compressor by increasing its capacity while enlarging its physical size out of concern for increased noise and vibration due to an increase in the rotation speed of the compressor, the compressive load increases, which also leads to deflection of main shaft portion 701.

[0018] Furthermore, misalignment or bearing clearance caused by assembly of main bearing 731 and sub-bearing 741 may also cause main shaft 701 and eccentric shaft 702 to be supported at an inclination relative to the bearing surfaces. With regard to the inclination of main shaft 701, taking into consideration the manufacturability and cost of the compressor, it is desirable to relax the assembly accuracy and component accuracy of rotating shaft 70, so the inclination of main shaft 701 tends to be large. Note that the bearing clearance is the gap formed between the shaft and bearing, in the portion where an oil film is formed that is compressed in the radial direction by the shaft and bearing.

[0019] To summarize, deformation and bending of rotating shaft 70 during compressor operation, as well as tilting of rotating shaft 70 during assembly, reduces the bearing clearance and makes uneven contact more likely to occur on the bearing surfaces of the bearing ends of main bearing portion 731 and sub-bearing portion 741. Furthermore, because main shaft portion 701 bends and tilts, the bearing clearance also reduces at the bearing surface of the bearing end of eccentric bearing portion 751 formed in eccentric bearing support member 75, making uneven contact more likely to occur.

[0020] Due to such deformation, bending, or tilt of the main shaft portion 701, the load distribution of each bearing portion 731, 741, 751 of the scroll compressor is not uniform in the axial direction Da, and the line load tends to become extremely high at each bearing portion 731, 741, 751.

[0021] 3A , in the ideal case where there is no deflection or tilt of main shaft portion 701 in main bearing portion 731, the load distribution Df of main bearing portion 731 is uniform in the axial direction Da. In this case, the surface pressure distribution in main bearing portion 731 is uniform, and the bearing clearance is wide, making it easy to ensure a sufficient oil film thickness.

[0022] In contrast, if main shaft portion 701 tilts and the contact angle αt of main shaft portion 701 with respect to the bearing surface of main bearing portion 731 increases compared to the state in Figure 3A, load distribution Df will no longer be uniform in the axial direction Da, and the line load will increase, as shown in Figure 3B. If main shaft portion 701 tilts further from the state in Figure 3B, the line load will increase further in load distribution Df, as shown in Figure 3C. In the cases of Figures 3B and 3C, the surface pressure distribution in main bearing portion 731 will be localized, and the bearing clearance will be locally narrowed, making it difficult to ensure a sufficient oil film thickness.

[0023] In other words, if the main shaft 701 is tilted, the range in the axial direction Da where oil film pressure is generated in each of the bearings 731, 741, and 751 becomes narrower, making it difficult to form an oil film. As a result, the oil film breaks, for example, at or near the bearing end of the main bearing 731, which can cause direct contact between the main bearing 731 and the main shaft 701, easily causing surface damage such as wear and seizure. Such a phenomenon can lead to increased sliding loss and wear, reducing not only the efficiency of the compressor but also its reliability.

[0024] (Structural Description of Patent Document 1) In the compressor of Patent Document 1, as shown in Figures 4A to 4C, a tapered crowning 701a is formed on a portion of main shaft portion 701 that is inserted into main bearing portion 731. To make the illustration easier to understand, crowning 701a of main shaft portion 701 is shown larger than in Patent Document 1. A similar crowning is also formed on eccentric shaft portion 702, but this is not shown in Figures 4A to 4C.

[0025] However, when taking into consideration fluctuations in radial compressive load Fpr and variations during compressor manufacturing, it is difficult to find an appropriate gradient angle βt for crowning 701a formed on main shaft portion 701 and eccentric shaft portion 702. Therefore, as shown in Figures 4A to 4C, even in the compressor of Patent Document 1, similar to the configuration without crowning shown in Figures 3A to 3C, the line load at each bearing portion tends to become extremely high in response to changes in inclination of main shaft portion 701 due to fluctuations in radial compressive load Fpr, etc.

[0026] 4A, when the contact angle αt of the main shaft portion 701 with respect to the bearing surface of the main bearing portion 731 is the same as or approximately the same as the gradient angle βt of the crowning 701a, the load distribution Df of the main bearing portion 731 becomes uniform in the axial direction Da. In this case, the surface pressure distribution in the main bearing portion 731 becomes uniform, making it easy to ensure a sufficient oil film thickness.

[0027] In contrast, when "contact angle αt < gradient angle βt" as shown in Figure 4B, the load distribution Df of the main bearing portion 731 is not uniform in the axial direction Da, the line load increases, and a locally large surface pressure is generated on the starting point side of the taper of the crowning 701a. Conversely, when "contact angle αt > gradient angle βt" as shown in Figure 4C, the load distribution Df of the main bearing portion 731 is not uniform in the axial direction Da, the line load increases, and a locally large surface pressure is generated on the tip side of the taper of the crowning 701a.

[0028] As described above, even in the compressor of Patent Document 1, the phenomenon of uneven contact is still likely to occur in the main bearing portion 731 and the eccentric bearing portion 751 that are crowned.

[0029] In view of the above points, the compressor 10 of the embodiment described below is configured so as not to increase sliding loss and wear, not to reduce the efficiency of the compressor 10, and to ensure sufficient reliability.

[0030] Hereinafter, each embodiment will be described with reference to the drawings. In the following embodiments, the same or equivalent parts are denoted by the same reference numerals in the drawings.

[0031] (First Embodiment) The compressor 10 of this embodiment shown in FIG. 5 constitutes, for example, a part of a vapor compression refrigeration cycle. In this refrigeration cycle, the compressor 10 draws in a refrigerant, compresses the drawn refrigerant, and then discharges the refrigerant. The refrigerant, which is a fluid (specifically, a gas) compressed by the compressor 10, is, for example, a hydrocarbon refrigerant or a carbon dioxide refrigerant, which is a natural refrigerant with a low global warming potential. Examples of such hydrocarbon refrigerants include butane, isobutane, and propane. The refrigerant is mixed with lubricating oil that lubricates the sliding parts inside the compressor 10. A portion of the lubricating oil circulates within the refrigeration cycle together with the refrigerant.

[0032] 5 to 7 indicate the vertical direction Dg in a state in which the compressor 10 is installed so as to be operable.

[0033] 5 to 7 , the compressor 10 includes a housing 12, a rotating shaft 14, a compression unit 20, an electric motor 30, a main bearing 36, a sub-bearing 40, an eccentric bearing 42, a first support member 44, a second support member 46, and a thrust plate 48. The rotating shaft 14, the compression unit 20, the electric motor 30, the main bearing 36, the sub-bearing 40, the eccentric bearing 42, the first support member 44, the second support member 46, and the thrust plate 48 are accommodated inside the housing 12. The compressor 10 has a horizontally mounted structure in which the rotating shaft 14 extends in a substantially horizontal direction and the compression unit 20 and the electric motor 30 are arranged in a substantially horizontal direction.

[0034] The housing 12 is a housing that forms the outer shell of the compressor 10 and is configured by a plurality of components that are integrally joined by bolts. For example, the housing 12 is configured of a metal material. Although not shown, the housing 12 is formed with an intake port through which the compressor 10 draws a refrigerant and a discharge port through which the compressor 10 discharges the refrigerant.

[0035] 5 to 8 , the rotating shaft 14 extends in the axial direction Da. In the description of this embodiment, the axial direction Da of the rotating shaft 14 may be referred to as a first axial direction D1a or a second axial direction D2a. Both the first axial direction D1a and the second axial direction D2a are the same direction as the axial direction Da of the rotating shaft 14, but one side of the first axial direction D1a is the other side of the second axial direction D2a, and the other side of the first axial direction D1a is one side of the second axial direction D2a.

[0036] The rotating shaft 14 has a main shaft portion 141, an eccentric shaft portion 142 provided on one side of the main shaft portion 141 in the first axial direction D1a, and an enlarged diameter portion 143 provided between the main shaft portion 141 and the eccentric shaft portion 142. The main shaft portion 141 and the eccentric shaft portion 142 are connected with the enlarged diameter portion 143 sandwiched therebetween, and the main shaft portion 141, the eccentric shaft portion 142, and the enlarged diameter portion 143 are integrally configured.

[0037] The main shaft portion 141 is formed around a main shaft center Ca extending along the first axial direction D1a and extends in the first axial direction D1a. The enlarged diameter portion 143 is formed around the main shaft center Ca and expands in a flange-like shape relative to the main shaft portion 141 in a first radial direction D1r, which is the radial direction of the main shaft portion 141. In short, the enlarged diameter portion 143 is a flange-shaped portion. The enlarged diameter portion 143 is provided with a balance weight 15 for suppressing eccentric rotation of the rotating shaft 14. The balance weight 15 is fixed to the enlarged diameter portion 143 so as to rotate integrally with the main shaft portion 141.

[0038] The eccentric shaft portion 142 is formed around an eccentric axis Cb extending along the second axial direction D2a, and extends in the second axial direction D2a. As described above, the eccentric shaft portion 142 is provided on one side of the main shaft portion 141 in the first axial direction D1a. In other words, the eccentric shaft portion 142 is provided on the compression section 20 side of the main shaft portion 141.

[0039] Furthermore, the eccentric axis Cb is offset in the first radial direction D1r with respect to the main axis Ca. That is, the eccentric shaft portion 142 is eccentric with respect to the main axis portion 141. The rotating shaft 14 of this embodiment is configured as a so-called fixed crank mechanism in which the amount of eccentricity of the eccentric axis Cb with respect to the main axis Ca is constant.

[0040] An oil supply passage 14a is formed inside the rotating shaft 14 to supply lubricating oil to sliding parts that slide as the rotating shaft 14 rotates. Examples of the sliding parts to which the lubricating oil is supplied include a main bearing 36, an auxiliary bearing 40, and an eccentric bearing 42, which will be described later. For example, the lubricating oil is stored in the housing 12, and the lubricating oil is supplied to the sliding parts, such as the main bearing 36, the auxiliary bearing 40, and the eccentric bearing 42, which will be described later, via an oil supply path (not shown) and the oil supply passage 14a.

[0041] The compression section 20 is configured as a scroll-type compression mechanism. As the rotary shaft 14 connected to the compression section 20 rotates, the compression section 20 draws refrigerant into a working chamber 21 formed therein, compresses the drawn refrigerant in the working chamber 21, and then discharges the refrigerant. Lubricating oil mixed in the refrigerant discharged from the working chamber 21 is separated from the refrigerant by, for example, an oil separator (not shown). The compression section 20 is also referred to as a compression mechanism section, and the working chamber 21 is also referred to as a compression chamber.

[0042] The compression section 20 has a fixed scroll 22, a movable scroll 24, an Oldham ring 25, and a discharge plate 26. The movable scroll 24, the fixed scroll 22, and the discharge plate 26 are arranged in this order along the first axial direction D1a. The fixed scroll 22, the movable scroll 24, and the discharge plate 26 are each made of a steel material, an aluminum alloy, or the like.

[0043] The fixed scroll 22 has a fixed base plate portion 221 formed in a disk shape and a spiral-shaped fixed tooth portion 222 protruding from the fixed base plate portion 221 toward the movable scroll 24 on the other side in the first axial direction D1a.

[0044] The movable scroll 24 has an orbiting base plate portion 241 formed in a disk shape and an orbiting tooth portion 242 in a spiral shape that protrudes from the orbiting base plate portion 241 toward the fixed scroll 22 on one side in the first axial direction D1a. The movable scroll 24 is also sometimes referred to as an orbiting scroll.

[0045] The movable scroll 24 also has a cylindrical eccentric bearing support portion 243 that protrudes from the orbiting base plate portion 241 to the side opposite the orbiting tooth portion 242. The eccentric bearing portion 42 is fitted inside the eccentric bearing support portion 243, and is unable to rotate relative to the eccentric bearing support portion 243. In other words, the eccentric bearing portion 42 is provided on the movable scroll 24 and is unable to rotate relative to the movable scroll 24.

[0046] The eccentric bearing portion 42 is a sliding bearing, and is made of, for example, a metal or resin material with high sliding properties. The eccentric bearing portion 42 has a cylindrical shape extending in the second axial direction D2a, and an eccentric bearing surface 42a, which serves as a bearing surface, is formed inside the eccentric bearing portion 42. This eccentric bearing surface 42a has a cylindrical inner surface with the same diameter regardless of its position in the second axial direction D2a. That is, in the vertical cross section of FIG. 6, the eccentric bearing surface 42a is linear and parallel to the second axial direction D2a. The eccentric bearing portion 42 has one end portion 421 provided on one side of the eccentric bearing portion 42 in the second axial direction D2a.

[0047] The eccentric shaft portion 142 of the rotating shaft 14 is inserted into the eccentric bearing portion 42, and the eccentric bearing portion 42 supports the eccentric shaft portion 142 so as to be relatively rotatable. Therefore, the eccentric shaft portion 142 has a journal portion 142a, which is the portion of the eccentric shaft portion 142 that is inserted into the eccentric bearing portion 42. The eccentric bearing portion 42 supports the journal portion 142a so as to be relatively rotatable.

[0048] In the description of this embodiment, the journal portion 142a of the eccentric shaft portion 142 may be referred to as the eccentric journal portion 142a. In this embodiment, the entirety or almost the entirety of the eccentric shaft portion 142 is the eccentric journal portion 142a.

[0049] 9, the eccentric bearing 42 supports the eccentric journal 142a so as to be relatively rotatable as described above, and therefore receives a radial load Fp from the eccentric journal 142a as the rotating shaft 14 rotates, and generates a reaction force Fcp that opposes the radial load Fp. The radial load Fp that the eccentric bearing 42 receives from the eccentric journal 142a may be referred to as an eccentric bearing radial load Fp in the description of this embodiment.

[0050] As shown in Figure 5, an Oldham ring 25 is connected to the movable scroll 24. The Oldham ring 25 constitutes a rotation prevention mechanism that prevents the movable scroll 24 from rotating on its axis. When the rotary shaft 14 rotates, the movable scroll 24 revolves (i.e., orbits) along a circular orbit around the main axis Ca, while being restricted from rotation by the Oldham ring 25. Note that various members or mechanisms other than the Oldham ring 25 may be used as the rotation prevention mechanism.

[0051] Between the fixed scroll 22 and the movable scroll 24, the fixed teeth 222 and the orbiting teeth 242 mesh with each other and come into contact at multiple locations, thereby forming multiple crescent-shaped working chambers 21. As the movable scroll 24 orbits, the working chambers 21 move from the outer periphery toward the center while decreasing in volume. Although not shown, refrigerant is drawn into the working chambers 21 through a refrigerant suction port formed on the outer periphery of the fixed scroll 22 and supplied to the working chambers 21. The refrigerant in the working chambers 21 is compressed as the volume of the working chambers 21 decreases. Note that, for convenience, only one of the multiple working chambers 21 is designated by a reference numeral in FIGS. 5 and 6 .

[0052] A discharge hole 223 is formed in the center of the fixed substrate portion 221 to discharge the refrigerant compressed in the working chamber 21. A check valve (not shown) is provided in this discharge hole 223 to prevent the refrigerant from flowing back into the working chamber 21.

[0053] The discharge plate 26 is disposed adjacent to the fixed scroll 22. A muffler chamber 261 is formed between the discharge plate 26 and the fixed scroll 22 to reduce discharge pulsation of the refrigerant discharged from the discharge hole 223. Although not shown, the discharge plate 26 is formed with an outlet port for discharging the refrigerant from the muffler chamber 261. The fixed scroll 22, the discharge plate 26, and a first support member 44 (described later) are all fixed to the housing 12 by bolts. The discharge plate 26 is not an essential component of the compression section 20.

[0054] The electric motor 30 is an inverter-driven DC motor that is driven by power supplied from an inverter (not shown). The electric motor 30 is an electric motor that drives the compression section 20, and has a rotor 31 that rotates integrally with the rotary shaft 14, and a stator 32 that is fixed to the housing 12. The electric motor 30 is configured as an inner rotor motor in which the rotor 31 is disposed inside the stator 32.

[0055] The rotor 31 is a cylindrical member arranged coaxially with the main shaft portion 141 of the rotary shaft 14. A permanent magnet (not shown) is arranged inside the rotor 31. The rotor 31 is arranged next to the compression section 20 on the other side in the first axial direction D1a, and the main shaft portion 141 is inserted inside the rotor 31. The rotor 31 is unable to rotate relative to the main shaft portion 141 and rotates integrally with the main shaft portion 141 around the main axis center Ca as the rotation center. For example, the main shaft portion 141 is fixed to the rotor 31 by being press-fitted into the inside of the rotor 31, or the like.

[0056] Furthermore, balance weights 311 and 312 are attached to the side surface of the rotor 31 to offset the imbalance of the eccentric rotation of the movable scroll 24 and the like.

[0057] The stator 32 of the electric motor 30 is composed of a stator core made of a metallic magnetic material and a coil wound around the stator core. The stator 32 is fixed to the housing 12. When power is supplied to the stator 32 from an inverter (not shown), the stator 32 generates a rotating magnetic field that rotates the rotor 31. As a result, the stator 32 rotates the rotating shaft 14 together with the rotor 31.

[0058] That is, the electric motor 30 drives the rotor 31 to rotate by supplying power to the stator 32, and the rotational force that rotates the rotor 31 is transmitted from the rotor 31 to the movable scroll 24 of the compression section 20 via the rotating shaft 14.

[0059] 5 and 6 , the first support member 44 is disposed between the electric motor 30 and the compression unit 20 in the first axial direction D1a and is fixed to the housing 12. The first support member 44 has a main bearing support portion 441 on the inner circumferential side of the first support member 44 for rotatably supporting the main shaft portion 141 of the rotating shaft 14, and a shaft insertion hole 441b, which is a through-hole with a circular cross section and into which the main shaft portion 141 is inserted, is formed inside the main bearing support portion 441. The first support member 44 functions as a support that rotatably supports the main shaft portion 141 of the rotating shaft 14 via the main bearing portion 36.

[0060] The first support member 44 is made of, for example, steel, aluminum alloy, etc. The movable scroll 24, the Oldham ring 25, a portion of the rotary shaft 14, etc. are accommodated in the internal space of the housing 12 between the first support member 44 and the fixed scroll 22.

[0061] The first support member 44 and the movable scroll 24 each have a portion that faces the first axial direction D1a, and a thrust plate 48 configured in an annular shape is disposed between the first support member 44 and the movable scroll 24. The thrust plate 48 allows the movable scroll 24 to slide relative to the first support member 44.

[0062] The main bearing 36 is fitted into the shaft insertion hole 441b of the first support member 44, and the main bearing 36 is unable to rotate relative to the main bearing support 441. In other words, both the main bearing 36 and the main bearing support 441 are fixed to the housing 12.

[0063] The main bearing support portion 441 and the main bearing portion 36 are disposed in a position between the rotor 31 and the enlarged diameter portion 143 in the first axial direction D1a. Therefore, the main bearing support portion 441 and the main bearing portion 36 are disposed in a position between the rotor 31 and the eccentric shaft portion 142 in the first axial direction D1a.

[0064] The main bearing support portion 441 is provided on one side in the first axial direction D1a and has a one-side end face 441a facing that side in the first axial direction D1a. The outermost diameter Dmx of the enlarged-diameter portion 143 of the rotating shaft 14 is larger than the hole diameter Dmn of the shaft insertion hole 441b of the main bearing support portion 441, and the one-side end face 441a faces the enlarged-diameter portion 143 of the rotating shaft 14 in the first axial direction D1a. The enlarged-diameter portion 143 slides in contact with the one-side end face 441a as the rotating shaft 14 rotates about the main axis Ca. Therefore, the enlarged-diameter portion 143 of the rotating shaft 14 functions as a thrust bearing.

[0065] The main bearing portion 36 is a sliding bearing, and is made of, for example, a metal or resin material with high sliding properties. The main bearing portion 36 has a cylindrical shape extending in the first axial direction D1a, and a main bearing surface 36a, which is a bearing surface, is formed inside the main bearing portion 36. This main bearing surface 36a has a cylindrical inner surface with the same diameter regardless of the position in the first axial direction D1a. That is, the main bearing surface 36a is linear and parallel to the first axial direction D1a in the vertical cross section of FIG. 6. The main bearing portion 36 has one end portion 361 provided on one side of the main bearing portion 36 in the first axial direction D1a.

[0066] 5, 6, and 8, the main shaft portion 141 of the rotating shaft 14 is inserted into the main bearing portion 36, and the main bearing portion 36 supports the main shaft portion 141 so as to be rotatable relative to the rotating shaft 14. Therefore, the main shaft portion 141 has a journal portion 141a, which is the portion of the main shaft portion 141 inserted into the main bearing portion 36. The main bearing portion 36 supports the journal portion 141a so as to be rotatable relative to the rotating shaft 14. In the description of this embodiment, the journal portion 141a inserted into the main bearing portion 36 may be referred to as the main journal portion 141a.

[0067] 9, the main bearing 36 supports the main journal 141a so as to be relatively rotatable as described above, and therefore receives a radial load Fa from the main journal 141a as the rotating shaft 14 rotates, and generates a reaction force Fca that opposes the radial load Fa. The radial load Fa that the main bearing 36 receives from the main journal 141a may be referred to as a main bearing radial load Fa in the description of this embodiment.

[0068] 5 and 7 , the second support member 46 is disposed within the housing 12 on the other side in the first axial direction D1a of the rotor 31 of the electric motor 30, and is fixed to the housing 12. The second support member 46 has an auxiliary bearing support portion 461 on the inner circumferential side of the second support member 46 for rotatably supporting the main shaft portion 141 of the rotating shaft 14, and a through hole with a circular cross section is formed inside the auxiliary bearing support portion 461, into which the main shaft portion 141 is inserted. The second support member 46 is made of, for example, steel material, aluminum alloy, or the like.

[0069] The sub-bearing portion 40 is fitted into a through hole formed inside the sub-bearing support portion 461 of the second support member 46, and the sub-bearing portion 40 is unable to rotate relative to the sub-bearing support portion 461. In other words, both the sub-bearing portion 40 and the sub-bearing support portion 461 are fixed to the housing 12.

[0070] The sub-bearing 40 and the sub-bearing support 461 are disposed on the other side in the first axial direction D1a of the rotor 31. In other words, the sub-bearing 40 and the sub-bearing support 461 are disposed on the opposite side of the rotor 31 from the main bearing 36 and the main bearing support 441 in the first axial direction D1a.

[0071] The sub-bearing 40 is a plain bearing, and is made of, for example, a metal or resin material with high sliding properties. The sub-bearing 40 has a cylindrical shape extending in the first axial direction D1a, and a sub-bearing surface 40a, which is a bearing surface, is formed inside the sub-bearing 40. This sub-bearing surface 40a has a cylindrical inner surface with the same diameter regardless of the position in the first axial direction D1a. That is, in the vertical cross section of FIG. 7 , the sub-bearing surface 40a is linear and parallel to the first axial direction D1a. The sub-bearing 40 has one end 401 provided on one side of the sub-bearing 40 in the first axial direction D1a.

[0072] 5, 7, and 8, the main shaft portion 141 of the rotating shaft 14 is inserted into the sub-bearing portion 40, and the sub-bearing portion 40 supports the main shaft portion 141 so as to be rotatable relative to the main shaft portion 141. Therefore, the sub-bearing portion 40 has a journal portion 141b, which is the portion of the main shaft portion 141 that is inserted into the sub-bearing portion 40. The sub-bearing portion 40 supports the journal portion 141b so as to be rotatable relative to the main shaft portion 141. In the description of this embodiment, the journal portion 141b inserted into the sub-bearing portion 40 may be referred to as the sub-journal portion 141b.

[0073] 9, the sub-bearing 40 supports the sub-journal 141b so as to be relatively rotatable as described above, and therefore receives a radial load Fb from the sub-journal 141b as the rotating shaft 14 rotates, and generates a reaction force Fcb that opposes the radial load Fb. The radial load Fb that the sub-bearing 40 receives from the sub-journal 141b may be referred to as a sub-bearing radial load Fb in the description of this embodiment.

[0074] As described above, as the rotating shaft 14 rotates, reaction forces Fca, Fcb, and Fcp against the radial loads Fa, Fb, and Fp act on the rotating shaft 14 from the respective bearings 36, 40, and 42, causing bending deformation of the rotating shaft 14. Therefore, as shown in Figure 9, the journals 141a, 141b, and 142a of the rotating shaft 14 are slightly tilted relative to the respective bearings 36, 40, and 42 as the rotating shaft 14 is bent.

[0075] Specifically, each of the journal portions 141a, 141b, and 142a tilts as follows. That is, in a longitudinal cross section of the main journal portion 141a, which is a cross section including the main axis center Ca, the main journal portion 141a tilts relative to the main bearing portion 36 in accordance with bending deformation of the rotating shaft 14. In this case, the main journal portion 141a tilts relative to the main bearing portion 36 so that the curved outer peripheral surface 141h of the main journal portion 141a slides on the main bearing portion 36. In other words, in the longitudinal cross section of the main journal portion 141a, the main journal portion 141a tilts so that one side of the main journal portion 141a in the first axial direction D1a is closer to the load-opposing portion 36b of the main bearing portion 36 than the other side. At this time, the main journal portion 141a receives, at the curved outer peripheral surface 141h, a reaction force Fca from the main bearing portion 36 that opposes the main bearing radial load Fa. The load-opposing portion 36b of the main bearing portion 36 refers to the portion 36b of the main bearing portion 36 that opposes the main bearing radial load Fa. The curved outer peripheral surface 141h of the main journal portion 141a will be described later with reference to Figures 6 and 8.

[0076] Furthermore, in a longitudinal cross section of the secondary journal portion 141b, which is a cross section including the main axis Ca, the secondary journal portion 141b tilts relative to the secondary bearing portion 40 in accordance with bending deformation of the rotating shaft 14. In this case, the secondary journal portion 141b tilts relative to the secondary bearing portion 40 so that a curved outer peripheral surface 141n of the secondary journal portion 141b slides against the secondary bearing portion 40. In other words, in the longitudinal cross section of the secondary journal portion 141b, the secondary journal portion 141b tilts so that one side of the secondary journal portion 141b in the first axial direction D1a is closer to the load-opposing portion 40b of the secondary bearing portion 40 than the other side. At this time, the secondary journal portion 141b receives, at its curved outer peripheral surface 141n, a reaction force Fcb from the secondary bearing portion 40 that opposes the secondary bearing radial load Fb. The load-opposing portion 40b of the sub-bearing portion 40 refers to the portion 40b of the sub-bearing portion 40 that opposes the sub-bearing radial load Fb. The curved outer peripheral surface 141n of the sub-journal portion 141b will be described later with reference to Figures 7 and 8.

[0077] Furthermore, in a vertical cross section of the eccentric journal portion 142a, which is a cross section including the eccentric axis Cb (see FIG. 8 ), the eccentric journal portion 142a tilts relative to the eccentric bearing portion 42 in accordance with bending deformation of the rotating shaft 14. In this case, the eccentric journal portion 142a tilts relative to the eccentric bearing portion 42 so that a curved outer peripheral surface 142h of the eccentric journal portion 142a slides on the eccentric bearing portion 42. In other words, in the above vertical cross section, the eccentric journal portion 142a tilts so that one side of the eccentric journal portion 142a in the second axial direction D2a is closer to the load-opposing portion 42b of the eccentric bearing portion 42 than the other side. At this time, the eccentric journal portion 142a receives, at its curved outer peripheral surface 142h, a reaction force Fcp of the eccentric bearing portion 42 that opposes the eccentric bearing radial load Fp. The load-opposing portion 42b of the eccentric bearing portion 42 refers to the portion 42b of the eccentric bearing portion 42 that opposes the eccentric bearing radial load Fp. The curved outer peripheral surface 142h of the eccentric journal portion 142a will be described later with reference to Figures 6 and 8.

[0078] As shown in FIGS. 6 and 8 , the main journal portion 141a has a maximum diameter portion 141d and a crowning portion 141g located on one side of the maximum diameter portion 141d in the first axial direction D1a. The maximum diameter portion 141d is the largest portion of the main journal portion 141a, and the outer diameter of the maximum diameter portion 141d is constant regardless of its position in the first axial direction D1a. In contrast, the crowning portion 141g is formed so that its diameter gradually decreases from the outer diameter of the maximum diameter portion 141d toward one side in the first axial direction D1a. The crowning portion 141g faces one end 361 of the main bearing portion 36 in the first radial direction D1r. The crowning portion 141g having a continuously decreasing diameter means that the crowning portion 141g has a smoothly decreasing diameter without any bends or steps on the outer peripheral surface of the crowning portion 141g.

[0079] The crowning portion 141g of the main journal portion 141a has a curved outer peripheral surface 141h and a tapered surface 141i as its outer peripheral surface. Both the curved outer peripheral surface 141h and the tapered surface 141i form a circular shape centered on the main axis Ca, which is the axial center of the main journal portion 141a, in a cross section perpendicular to the main axis Ca.

[0080] The curved outer peripheral surface 141h of the main journal portion 141a is curved and continuously connected to the outer peripheral surface 141e of the maximum diameter portion 141d in a longitudinal cross section that includes the main axis center Ca. "Continuously connected" means, in other words, "smoothly connected without bending." In other words, the curved outer peripheral surface 141h extends smoothly from the outer peripheral surface 141e of the maximum diameter portion 141d to one side in the first axial direction D1a without bending. Furthermore, the curved outer peripheral surface 141h is curved convexly, not concavely, in a longitudinal cross section of the main journal portion 141a.

[0081] Specifically, the curved outer peripheral surface 141h of the main journal portion 141a has an arc shape with a constant radius of curvature Ra in a longitudinal cross section of the main journal portion 141a. The radius of curvature Ra of the curved outer peripheral surface 141h of the main journal portion 141a is, for example, approximately 3000 to 5000 mm. The radii of curvature Rb and Rp of the curved outer peripheral surfaces 141n and 142h of the sub-journal portion 141b and eccentric journal portion 142a, which will be described later, are also approximately equal to this radius of curvature.

[0082] The tapered surface 141i of the main journal portion 141a is provided on one side of the curved outer peripheral surface 141h in the first axial direction D1a. The tapered surface 141i extends linearly and is inclined with respect to the main axis center Ca in the vertical cross section of the main journal portion 141a, and is continuously connected to the curved outer peripheral surface 141h.

[0083] 8, in the main journal portion 141a, in the first axial direction D1a, the curved range Wa1 in which the curved outer peripheral surface 141h is formed is larger than the tapered range Wa2 in which the tapered surface 141i is formed. In this embodiment, the tapered range Wa2 is the range obtained by excluding the curved range Wa1 from the crowning range Wa occupied by the crowning portion 141g in the first axial direction D1a.

[0084] As shown in Figures 7 and 8, the secondary journal portion 141b is formed in the same manner as the main journal portion 141a. Specifically, the secondary journal portion 141b has a maximum diameter portion 141j and a crowning portion 141m located on one side of the maximum diameter portion 141j in the first axial direction D1a. The maximum diameter portion 141j is the portion of the secondary journal portion 141b with the largest diameter, and the outer diameter of the maximum diameter portion 141j is constant regardless of its position in the first axial direction D1a. In contrast, the crowning portion 141m is formed so that its diameter gradually decreases from the outer diameter of the maximum diameter portion 141j toward one side in the first axial direction D1a. Furthermore, the crowning portion 141m faces one end 401 of the secondary bearing portion 40 in the first radial direction D1r.

[0085] The crowning portion 141m of the sub-journal portion 141b has a curved outer peripheral surface 141n and a tapered surface 141o as its outer peripheral surface. Both the curved outer peripheral surface 141n and the tapered surface 141o form a circular shape centered on the main axis Ca, which is the axial center of the sub-journal portion 141b, in a cross section perpendicular to the main axis Ca.

[0086] The curved outer peripheral surface 141n of the sub-journal portion 141b is curved in a longitudinal cross section that includes the main axis center Ca and continues to the outer peripheral surface 141k of the maximum diameter portion 141j. In other words, the curved outer peripheral surface 141n extends smoothly from the outer peripheral surface 141k of the maximum diameter portion 141j to one side in the first axial direction D1a without bending. The curved outer peripheral surface 141n is curved convexly, not concavely, in the longitudinal cross section of the sub-journal portion 141b.

[0087] More specifically, the curved outer peripheral surface 141n of the sub-journal portion 141b has an arc shape with a constant radius of curvature Rb in the vertical cross section of the sub-journal portion 141b.

[0088] The tapered surface 141o of the sub-journal portion 141b is provided on one side of the curved outer peripheral surface 141n in the first axial direction D1a. The tapered surface 141o extends linearly and is inclined with respect to the main axis center Ca in the vertical cross section of the sub-journal portion 141b, and is continuously connected to the curved outer peripheral surface 141n.

[0089] 8, in the sub-journal portion 141b, in the first axial direction D1a, a curved range Wb1 in which the curved outer peripheral surface 141n is formed is larger than a tapered range Wb2 in which the tapered surface 141o is formed. In this embodiment, the tapered range Wb2 is the range obtained by excluding the curved range Wb1 from the crowning range Wb occupied by the crowning portion 141m in the first axial direction D1a.

[0090] As shown in FIGS. 6 and 8 , the eccentric journal portion 142a is formed similarly to the main journal portion 141a inverted in the second axial direction D2a. Specifically, the eccentric journal portion 142a has a maximum diameter portion 142d and a crowning portion 142g located on one side of the maximum diameter portion 142d in the second axial direction D2a. The maximum diameter portion 142d is the largest part of the eccentric journal portion 142a, and the outer diameter of the maximum diameter portion 142d is constant regardless of its position in the second axial direction D2a. In contrast, the crowning portion 142g is formed so that its diameter gradually decreases from the outer diameter of the maximum diameter portion 142d toward one side in the second axial direction D2a. Furthermore, the crowning portion 142g faces one end 421 of the eccentric bearing portion 42 in the second radial direction D2r, which is the radial direction of the eccentric shaft portion 142.

[0091] The crowning portion 142g of the eccentric journal portion 142a has a curved outer peripheral surface 142h and a tapered surface 142i as its outer peripheral surface. Both the curved outer peripheral surface 142h and the tapered surface 142i form a circular shape centered on the eccentric axis Cb, which is the axis of the eccentric journal portion 142a, in a cross section perpendicular to the eccentric axis Cb.

[0092] The curved outer peripheral surface 142h of the eccentric journal portion 142a is curved in a vertical cross section that includes the eccentric axis Cb and continues to the outer peripheral surface 142e of the maximum diameter portion 142d. In other words, the curved outer peripheral surface 142h extends smoothly from the outer peripheral surface 142e of the maximum diameter portion 142d toward one side in the second axial direction D2a without bending. The curved outer peripheral surface 142h is curved convexly, not concavely, in the vertical cross section of the eccentric journal portion 142a.

[0093] More specifically, the curved outer peripheral surface 142h of the eccentric journal portion 142a has an arc shape with a constant radius of curvature Rp in the vertical cross section of the eccentric journal portion 142a.

[0094] The tapered surface 142i of the eccentric journal portion 142a is provided on one side of the curved outer peripheral surface 142h in the second axial direction D2a. The tapered surface 142i extends linearly and is inclined with respect to the eccentric axis Cb in the vertical cross section of the eccentric journal portion 142a, and is continuously connected to the curved outer peripheral surface 142h.

[0095] 8, in the eccentric journal portion 142a, a curved range Wp1 in which the curved outer peripheral surface 142h is formed is larger than a tapered range Wp2 in which the tapered surface 142i is formed in the second axial direction D2a. In this embodiment, the tapered range Wp2 is the range obtained by excluding the curved range Wp1 from the crowning range Wp occupied by the crowning portion 142g in the second axial direction D2a.

[0096] As described above, according to this embodiment, the main journal portion 141a has a maximum diameter portion 141d and a crowning portion 141g provided on one side of the maximum diameter portion 141d in the first axial direction D1a. The crowning portion 141g has a curved outer peripheral surface 141n. The main journal portion 141a is inclined with respect to the main bearing portion 36, and the reaction force Fca of the main bearing portion 36, which acts against the main bearing radial load Fa, is received by the curved outer peripheral surface 141h.

[0097] Here, for example, assume that the main journal portion 141a is slightly tilted with respect to the main bearing portion 36, as shown in Figures 10A and 10B. In this case, the bearing clearance Cc that forms the oil film between the main journal portion 141a and the main bearing portion 36 is formed between the main bearing surface 36a and the curved outer peripheral surface 141h of the main journal portion 141a, as shown in Figure 11 in detail. Therefore, even if the rotating shaft 14 is bent or tilted, for example, the bearing clearance Cc is unlikely to change. In Figure 11, the oil film in the bearing clearance Cc is represented by dotted hatching.

[0098] 10A to 13B, even if the inclination angle α of the main journal 141a with respect to the main bearing 36 fluctuates in accordance with changes in the load on the rotating shaft 14, the bearing clearance Cc continues to be formed between the curved outer peripheral surface 141h of the main journal 141a and the main bearing surface 36a. This makes it possible to stably maintain the bearing clearance Cc. As a result, the lubrication state between the main journal 141a and the main bearing 36 is less likely to fluctuate, making it possible to prevent the contact surface pressure Pf of the main bearing surface 36a from becoming excessive.

[0099] Therefore, the oil film is not broken and the main bearing surface 36a is not damaged due to direct contact between the main bearing 36 and the main shaft 141 over the entire sliding range including the vicinity of one end 361 of the main bearing 36, and a fluid lubrication state can be maintained. Therefore, a radial bearing with a low coefficient of friction and small sliding loss can be realized at low cost.

[0100] In addition, since the compressor 10 as a finished product has specifications that allow for bending of the rotating shaft 14, it is possible to standardize parts for the rotating shaft 14, for example, in various uses of the compressor 10, such as different capacity requirements. Also, since the compressor 10 has specifications that allow for tilting of the rotating shaft 14, it is possible to moderately relax assembly precision and part precision, allowing for low-cost manufacturing.

[0101] The curved surface forming angle range θ shown in Fig. 10B is the angular range occupied by the curved outer peripheral surface 141h in the vertical cross section of the main journal portion 141a. The contact point movement angular range ψ is the maximum angular range over which the contact point between the curved outer peripheral surface 141h and the main bearing surface 36a moves on the curved outer peripheral surface 141h in response to load fluctuations during operation of the compressor 10. The bearing length Ls of the main bearing portion 36 shown in Fig. 10A is the length of the main bearing surface 36a in the first axial direction D1a, and the bearing diameter Ds of the main bearing portion 36 is the inner diameter of the main bearing surface 36a.

[0102] 10B, the curved surface forming angular range θ and the contact point moving angular range ψ satisfy "θ > ψ." Also, as shown in FIG. 10A, the curved surface forming axial range Wθ, which is obtained by replacing the curved surface forming angular range θ with the range along the first axial direction D1a, and the contact point moving axial range Wψ, which is obtained by replacing the contact point moving angular range ψ with the range along the first axial direction D1a, satisfy the same rule. That is, the curved surface forming axial range Wθ and the contact point moving axial range Wψ satisfy "Wθ > Wψ."

[0103] The above are effects achieved by the configuration of the main journal portion 141a, but the sub-journal portion 141b and the eccentric journal portion 142a also have a configuration that achieves these effects. Therefore, the sub-journal portion 141b and the eccentric journal portion 142a can also achieve the same effects as those described above. Note that in the following explanation, the effects of the main journal portion 141a will be explained, and an explanation of the effects achieved by the sub-journal portion 141b and the eccentric journal portion 142a having the same configuration as the main journal portion 141a will be omitted.

[0104] Here, the relationship between the ratio LW / Ls, obtained by dividing the axial length LW of the curved range Wa1 (see FIG. 8) of the crowning portion 141g of the main journal portion 141a by the bearing length Ls of the main bearing portion 36, and the generated surface pressure P1 of the main bearing surface 36a, is shown by a curve Lp1 in FIG. 14. Furthermore, the relationship between the ratio LW / Ls and the minimum oil film thickness T1 formed in the bearing clearance Cc in FIG. 11 is shown by a curve Lt1 in FIG.

[0105] Figure 14 shows the results of a computer simulation. In this computer simulation, the curved surface forming angle range θ in Figure 11 is kept constant, and the axial length LW of the curved range Wa1 of the crowning portion 141g is changed by changing the radius of curvature Ra of the curved outer peripheral surface 141h. In addition, the bearing length Ls of the main bearing portion 36 is set to 20 mm, and the bearing diameter Ds of the main bearing portion 36 is set to 24 mm.

[0106] From a practical standpoint, it is desirable that the generated surface pressure P1 of the main journal portion 141a be equal to or less than a predetermined generated surface pressure threshold P1t, and that the minimum oil film thickness T1 be equal to or greater than a predetermined minimum oil film thickness threshold T1t. Therefore, from Figure 14, it is considered desirable that the ratio LW / Ls be "LW / Ls ≥ 0.2".

[0107] Although the upper limit of the ratio LW / Ls is not particularly limited, a preferable upper limit value is 1.0 or less, since the contact point must be within the bearing length Ls of the main bearing portion 36. In this case, the axial length LW of the curved range Wa1 is approximately equal to the bearing length Ls, so the bearing length Ls can be used as effectively as possible. Therefore, a preferable range for the ratio LW / Ls in this embodiment is 0.2 to 1.0.

[0108] (1) Furthermore, according to this embodiment, as shown in Figures 6 and 8, the curved outer peripheral surface 141h of the main journal portion 141a forms an arc shape with a constant radius of curvature Ra in the longitudinal cross section of the main journal portion 141a. Therefore, even if the inclination angle α of the main journal portion 141a changes due to variations in the bending or inclination of the rotating shaft 14, the bearing clearance Cc in Figure 11 does not change, and therefore the lubrication state between the main journal portion 141a and the main bearing portion 36 does not change. Therefore, compared to a configuration in which the radius of curvature Ra of the curved outer peripheral surface 141h is not constant, it is possible to further prevent the contact surface pressure Pf of the main bearing surface 36a from becoming excessive.

[0109] (2) Furthermore, according to this embodiment, in the first axial direction D1a, the curved range Wa1 of the curved outer peripheral surface 141h is larger than the tapered range Wa2, which is the range obtained by subtracting the curved range Wa1 from the crowning range Wa occupied by the crowning portion 141g. Therefore, it is possible to fully utilize the above-mentioned advantageous effect of the curved outer peripheral surface 141h, that is, the ability to stably maintain the bearing clearance Cc and suppress fluctuations in the lubrication state.

[0110] (3) Furthermore, according to this embodiment, the crowning portion 141g of the main journal portion 141a has a tapered surface 141i provided on one side of the curved outer peripheral surface 141h in the first axial direction D1a. The tapered surface 141i extends linearly and is inclined with respect to the main axis center Ca in the vertical cross section of the main journal portion 141a, and is continuously connected to the curved outer peripheral surface 141h.

[0111] In this embodiment, it is important that the crowning portion 141g has a curved outer peripheral surface 141h. By providing the linear tapered surface 141i as described above, it is possible to easily inspect the quality of the curved outer peripheral surface 141h. Specifically, the radius of curvature Ra of the curved outer peripheral surface 141h or the length of the curved outer peripheral surface 141h can be easily measured from the shape of the tangent of an imaginary line along the outer peripheral surface 141e of the maximum diameter portion 141d and an imaginary line along the tapered surface 141i in the vertical cross section.

[0112] (4) Furthermore, according to this embodiment, the first support member 44 functions as a support that rotatably supports the main shaft portion 141 of the rotating shaft 14. The outermost diameter Dmx of the enlarged diameter portion 143 of the rotating shaft 14 is larger than the hole diameter Dmn of the shaft insertion hole 441b of the first support member 44. The enlarged diameter portion 143 of the rotating shaft 14 faces the one-side end face 441a formed on the first support member 44 in the first axial direction D1a. As a result, the first support member 44 and the enlarged diameter portion 143 of the rotating shaft 14 can regulate positional deviation of the rotating shaft 14 relative to the main bearing portion 36 to the other side in the first axial direction D1a.

[0113] Furthermore, as the rotating shaft 14 rotates about the main axis Ca, the enlarged diameter portion 143 of the rotating shaft 14 slides in contact with the one-side end surface 441 a formed on the first support member 44. This enables the first support member 44 and the enlarged diameter portion 143 of the rotating shaft 14 to form a bearing configuration that resists a thrust load that attempts to shift the rotating shaft 14 to the other side in the first axial direction D1 a relative to the main bearing portion 36.

[0114] In addition to this bearing configuration, it is also envisioned that the rotor 31 is offset in the first axial direction D1a relative to the stator 32 of the electric motor 30, and that a thrust force acting toward the other side in the first axial direction D1a is applied to the rotating shaft 14 by the attractive force of the stator 32. In this way, the relative positional relationship between the main journal portion 141a and the main bearing portion 36 in the first axial direction D1a is determined, and it is possible to slide the curved outer peripheral surface 141h of the main journal portion 141a against the main bearing surface 36a without dropping off. Note that, although the enlarged diameter portion 143 integral with the main shaft portion 141 has been described above as corresponding to the flange portion of the present disclosure, it is also envisioned that a separate member fixed to the main shaft portion 141 may correspond to the flange portion of the present disclosure. For example, in this embodiment, the balance weight 15 faces the one-side end face 441a in the first axial direction D1a, and therefore the portion of the balance weight 15 facing the one-side end face 441a corresponds to the separate member described above, which corresponds to the flange portion of the present disclosure. In this case, the portion of the balance weight 15 facing the one-side end face 441a also serves to limit the relative position of the rotating shaft 14 with respect to the main bearing 36 in the first axial direction D1a. Just to be clear, even if the rotor 31 is not offset from the stator 32 of the electric motor 30, the relative positional relationship between the main bearing 36 and the rotating shaft 14 is determined within the component tolerances, so the offset position of the rotor 31 is not an essential configuration.

[0115] (5) According to the present embodiment, the compression unit 20 is a scroll type. Here, a scroll type compression mechanism is a type in which the load offset in the axial direction Da is large and the deflection of the rotating shaft 14 is also large. By providing the crowning portion 141g as described above on the main journal portion 141a, it is possible to provide high durability to the compressor 10 in which the deflection of the rotating shaft 14 is large.

[0116] (6) Furthermore, according to this embodiment, at least one of the main journal portion 141a, the sub-journal portion 141b, and the eccentric journal portion 142a is provided with crowning portions 141g, 141m, and 142g having curved outer peripheral surfaces 141h, 141n, and 142h. Therefore, by providing the crowning portions 141g, 141m, and 142g in accordance with the shape and load of the compressor 10, it is possible to appropriately obtain the effects of the crowning portions 141g, 141m, and 142g. Note that in this embodiment, the main journal portion 141a, the sub-journal portion 141b, and the eccentric journal portion 142a are provided with the crowning portions 141g, 141m, and 142g, respectively.

[0117] (7) Furthermore, according to this embodiment, the fluid compressed by the compression section 20 is a hydrocarbon refrigerant or a carbon dioxide refrigerant.

[0118] When a hydrocarbon refrigerant is used, for example, if mineral oil or alkylbenzene oil, which is highly soluble in hydrocarbon refrigerants, is used as the refrigeration oil, the viscosity of the refrigeration oil will drop significantly, making the sliding conditions of the main bearing 36 and other components that are subjected to radial loads even more severe. In contrast, the present embodiment employs the main journal 141a and other components that have the crowning portion 141m described above, which makes it possible to improve wear resistance and achieve high reliability.

[0119] Furthermore, when carbon dioxide refrigerant is used as the refrigerant, the radial load acting on the main bearing 36 and other components becomes extremely large, resulting in even more severe sliding conditions for the main bearing 36 and other components. To address this, the use of the main journal 141a and other components having the crowning portion 141m, as described above, makes it possible to improve wear resistance and obtain high reliability.

[0120] Second Embodiment Next, a second embodiment will be described. In this embodiment, differences from the first embodiment will be mainly described. Furthermore, parts that are the same as or equivalent to the first embodiment will be omitted or simplified. This also applies to the following embodiments.

[0121] As shown in Fig. 8, in the first embodiment, the crowning portion 141g of the main journal portion 141a has a curved outer peripheral surface 141h and a tapered surface 141i, but the tapered surface 141i is not an essential component. In the present embodiment, the tapered surface 141i is not provided, and as shown in Fig. 15, the crowning portion 141g of the main journal portion 141a has only the curved outer peripheral surface 141h as the outer peripheral surface of the crowning portion 141g.

[0122] Similarly, in this embodiment, the crowning portion 141m of the sub-journal portion 141b does not have a tapered surface 141o, and the crowning portion 141m has only a curved outer peripheral surface 141n as its outer peripheral surface.The crowning portion 142g of the eccentric journal portion 142a does not have a tapered surface 142i, and the crowning portion 142g has only a curved outer peripheral surface 142h as its outer peripheral surface.

[0123] In this embodiment, the range obtained by excluding the curved ranges Wa1, Wb1, and Wp1 from the crowning ranges Wa, Wb, and Wp (see FIG. 8) in the axial direction Da of the rotary shaft 14 is zero.

[0124] Except for the points described above, this embodiment is similar to the first embodiment. In this embodiment, the same effects as those of the first embodiment can be obtained from the configuration common to the first embodiment.

[0125] Third Embodiment Next, a third embodiment will be described. In this embodiment, differences from the first embodiment will be mainly described.

[0126] 16, the compressor 10 of this embodiment includes a driven crank mechanism 50 that automatically adjusts the eccentricity er of the eccentric axis Cb relative to the main axis Ca in accordance with the rotation of the rotating shaft 14. The driven crank mechanism 50 is a swing link type driven crank mechanism.

[0127] To configure the driven crank mechanism 50, the eccentric shaft portion 142 of the rotating shaft 14 is configured as a separate component from the main shaft portion 141 and the enlarged diameter portion 143. Therefore, the main shaft portion 141 and the enlarged diameter portion 143 are configured as a single component, and the eccentric shaft portion 142 is configured as a separate component from that single component. The rotating shaft 14 also includes a swing pin 144. In this embodiment, the eccentric journal portion 142a of the eccentric shaft portion 142 has a maximum diameter portion 142d and a crowning portion 142g, similar to the first embodiment.

[0128] The driven crank mechanism 50 of this embodiment is composed of a swing pin 144, an eccentric shaft portion 142 serving as a swing bush, and the eccentric bearing portion 42. This eccentric bearing portion 42 is sometimes referred to as a bushing within the driven crank mechanism 50.

[0129] In this embodiment, an eccentric hole 142k having a circular cross section is formed inside the eccentric shaft portion 142. The eccentric hole 142k penetrates the eccentric shaft portion 142 in the second axial direction D2a. The eccentric hole 142k is eccentric with respect to the eccentric axis Cb, which is the center line of the eccentric shaft portion 142.

[0130] The swing pin 144 is a cylindrical pin extending along the second axial direction D2a. The swing pin 144 is fixed to the enlarged diameter portion 143 by press-fitting or the like, and is disposed so as to protrude from the enlarged diameter portion 143 to the other side in the second axial direction D2a. The swing pin 144 is inserted into the eccentric hole 142k of the eccentric shaft portion 142 and supports the eccentric shaft portion 142 so as to be rotatable relative to the swing pin 144. The eccentric shaft portion 142 is rotatable relative to the swing pin 144, but is prevented from moving relative to the eccentric shaft portion 142 in the second axial direction D2a by a retaining ring (not shown) or the like.

[0131] A pin axis Cp, which is the center of rotation of the eccentric shaft portion 142 relative to the swing pin 144, is eccentric with respect to both the main axis Ca and the eccentric axis Cb.

[0132] Because the driven crank mechanism 50 is configured in this manner, the movable scroll 24 is connected to the main shaft portion 141 of the rotating shaft 14 via this driven crank mechanism 50. Therefore, the movable scroll 24 can revolve around the main shaft center Ca while being supported by the main shaft portion 141 in a state in which the eccentricity amount er of the eccentric axis Cb relative to the main shaft center Ca is variable. The eccentricity amount er of the eccentric axis Cb relative to the main shaft center Ca is the orbital radius of the movable scroll 24.

[0133] This eccentricity er tends to increase when the driven crank mechanism 50 transmits torque from the main shaft portion 141 to the movable scroll 24, thereby pushing the movable scroll 24 outward in the first radial direction D1r. Therefore, the orbital radius of the movable scroll 24, which is the eccentricity er, is determined in a state in which the orbiting teeth 242 come into contact with the fixed teeth 222 and are prevented from moving outward in the first radial direction D1r.

[0134] As described above, according to this embodiment, the compressor 10 is equipped with a driven crank mechanism 50, which can absorb variations in the precision of parts such as the rotating shaft 14 and allow the rotating tooth portion 242 to slide against the fixed tooth portion 222 while pressing it with an appropriate force.

[0135] Except for the points described above, this embodiment is similar to the first embodiment. In this embodiment, the same effects as those of the first embodiment can be obtained from the configuration common to the first embodiment. Note that this embodiment is a modification based on the first embodiment, but it is also possible to combine this embodiment with the second embodiment described above.

[0136] (Other Embodiments) (1) In each of the above-described embodiments, the fluid compressed by the compressor 10 is a hydrocarbon refrigerant or a carbon dioxide refrigerant, but is not limited thereto and may be, for example, a fluorocarbon-based refrigerant. Furthermore, the fluid compressed by the compressor 10 may be a fluid other than a refrigerant.

[0137] (2) In the first embodiment described above, the main journal portion 141a, the sub-journal portion 141b, and the eccentric journal portion 142a all have the crowning portions 141g, 141m, and 142g as shown in Figure 8. However, this is just one example. For example, any of the main journal portion 141a, the sub-journal portion 141b, and the eccentric journal portion 142a may be formed with a constant diameter over its entire length regardless of its position in the axial direction Da of the rotating shaft 14 without having the crowning portions 141g, 141m, and 142g.

[0138] (3) In each of the above-described embodiments, as shown in FIG. 5 , the lubricating oil is supplied to the sliding parts, such as the main bearing 36, the sub-bearing 40, and the eccentric bearing 42, via the oil supply passage 14 a. However, this is not limiting, and various supply paths for the lubricating oil to each sliding part are conceivable.

[0139] (4) In each of the above-described embodiments, as shown in Fig. 5, the Oldham ring 25 is used as the rotation prevention mechanism for the movable scroll 24, but this is just one example. For example, the rotation prevention mechanism may be a pin-ring type or a pin-ring-pin type.

[0140] (5) In each of the above-described embodiments, as shown in Fig. 5 , the enlarged diameter portion 143, which serves as a flange that regulates the position of the rotating shaft 14 in the axial direction Da, is disposed between the main shaft portion 141 and the eccentric shaft portion 142. However, this is merely an example. As long as the flange fulfills the role of regulating the position of the rotating shaft 14 in the axial direction Da in the same manner as the enlarged diameter portion 143 in Fig. 5 , it may be disposed at a location other than between the main shaft portion 141 and the eccentric shaft portion 142.

[0141] (6) In each of the above-described embodiments, the compression unit 20 is configured as a scroll-type compression mechanism as shown in FIG. 5 , but this is merely an example. The compression unit 20 may be configured as a piston-type or vane-type compression mechanism. Also, while the compressor 10 in FIG. 5 has a horizontal configuration, it may also have a vertical configuration.

[0142] (7) In each of the above-described embodiments, it has been described that bending deformation occurs in the rotating shaft 14 as shown in FIG. 9 . However, even if such bending deformation does not occur, the crowning portions 141 g and 142 g of the main journal portion 141 a and the eccentric journal portion 142 a are still useful.

[0143] Specifically, there is a radial clearance between the bearing 36, 40, 42 and the journal 141 a, 141 b, 142 a in each of the bearings 36, 40, 42. Therefore, even if the rigidity of the rotating shaft 14 is high and the rotating shaft 14 does not bend, the journal 141 a, 141 b, 142 a will tilt relative to the bearing 36, 40, 42 within the radial clearance, as shown in FIG.

[0144] 8 and 17, in the main bearing portion 36, the main journal portion 141a receives, on its curved outer peripheral surface 141h, the reaction force Fca of the main bearing portion 36, which counteracts the main bearing radial load Fa, and therefore the crowning portion 141g of the main journal portion 141a is effective. Also, in the eccentric bearing portion 42, the eccentric journal portion 142a receives, on its curved outer peripheral surface 142h, the reaction force Fcp of the eccentric bearing portion 42, which counteracts the eccentric bearing radial load Fp, and therefore the crowning portion 142g of the eccentric journal portion 142a is also effective.

[0145] When the rotating shaft 14 does not bend as shown in Fig. 17, the width of the curved outer peripheral surface 141h of the main journal portion 141a in the first axial direction D1a may be smaller than when bending deformation occurs in the rotating shaft 14 as shown in Fig. 9. The same applies to the curved outer peripheral surface 142h of the eccentric journal portion 142a.

[0146] (8) As a modification of the third embodiment described above, as shown in FIG. 18 , which replaces FIG. 16 , it is also possible for the enlarged-diameter portion 143 to have a diameter smaller than the shaft insertion hole 441b of the first support member 44. In this modification shown in FIG. 18 , the balance weight 15 fixed to the enlarged-diameter portion 143 faces the one-side end surface 441a of the first support member 44 in the first axial direction D1a and slides in contact with the one-side end surface 441a as the rotating shaft 14 rotates about the main axis Ca. This restricts the axial position of the rotating shaft 14 relative to the main bearing 36 and the sub-bearing 40. In this modification shown in FIG. 18 , the portion of the balance weight 15 facing the one-side end surface 441a corresponds to the flange portion of the present disclosure.

[0147] (9) The present disclosure is not limited to the above-described embodiments and can be implemented in various modified forms. Furthermore, the above-described embodiments are not unrelated to each other and can be combined as appropriate, except in cases where the combination is clearly impossible.

[0148] Furthermore, in each of the above embodiments, it goes without saying that the elements constituting the embodiments are not necessarily essential unless they are particularly explicitly stated as essential or are clearly considered essential in principle. Furthermore, in each of the above embodiments, when the numbers, values, amounts, ranges, etc. of the components of the embodiments are mentioned, they are not limited to the specific numbers unless they are particularly explicitly stated as essential or are clearly limited to a specific number in principle. Furthermore, in each of the above embodiments, when the materials, shapes, positional relationships, etc. of the components are mentioned, they are not limited to the materials, shapes, positional relationships, etc. unless they are particularly explicitly stated or are clearly limited to a specific material, shape, positional relationship, etc. in principle.

[0149] (Aspects of the present disclosure) The above-described present disclosure can be understood from the following aspects, for example. [First aspect] A compressor comprising: a rotating shaft (14) having at least one journal portion (141a, 141b, 142a) and extending in an axial direction (Da, D1a, D2a), a compression portion (20) that compresses a fluid as the rotating shaft rotates, and at least one plain bearing portion (36, 40, 42) having one end (361, 401, 421) provided on one side in the axial direction, into which the journal portion is inserted, supporting the journal portion so as to be rotatable relative to the journal portion, and receiving a radial load (Fa, Fb, Fp) from the journal portion, the journal portion has a maximum diameter portion (141d, 141j, 142d) having the largest diameter among the journal portions, and a crowning portion (141g, 141m, 142g) provided on one side in the axial direction of the maximum diameter portion, facing the one end portion in the radial direction (D1r, D2r) of the journal portion, and having a diameter that continuously decreases toward the one side in the axial direction, the crowning portion has a curved outer circumferential surface (141h, 141n, 142h) that is curved in a vertical cross section including an axis (Ca, Cb) of the journal portion and is continuous with the outer circumferential surface (141e, 141k, 142e) of the maximum diameter portion, the journal portion is inclined with respect to the plain bearing portion, and a reaction force (Fca, Fcb, Fcp) of the plain bearing portion that resists the radial load is received by the curved outer circumferential surface. [Second Aspect] The compressor according to the first aspect, wherein the curved outer peripheral surface forms an arc shape having a constant radius of curvature (Ra, Rb, Rp) in the longitudinal cross section. [Third Aspect] The compressor according to the first or second aspect, wherein, in the axial direction, a curved range (Wa1, Wb1, Wp1) in which the curved outer peripheral surface is formed is larger than a range (Wa2, Wb2, Wp2) obtained by excluding the curved range from a range (Wa, Wb, Wp) occupied by the crowning portion. [Fourth Aspect] The compressor according to any one of the first to third aspects, wherein the crowning portion has a tapered surface (141i, 141o, 142i) provided on one side of the curved outer peripheral surface in the axial direction, and the tapered surface extends linearly at an angle with respect to the axis in the longitudinal cross section and is continuously connected to the curved outer peripheral surface.[Fifth Aspect] The compressor according to any one of the first to fourth aspects, further comprising a support (44) that rotatably supports the rotating shaft, the support (44) being formed with a shaft insertion hole (441b) into which the rotating shaft is inserted, the rotating shaft having a flange portion (143), the flange portion facing the support in the axial direction, and an outermost diameter (Dmx) of the flange portion being larger than a diameter (Dmn) of the shaft insertion hole. [Sixth Aspect] The compressor according to any one of the first to fifth aspects, wherein the compression section is of a scroll type. [Seventh Aspect] An electric motor (30) including a rotor (31) arranged alongside the compression section in the axial direction and a stator (32) that rotates the rotary shaft together with the rotor; a main bearing (36); an auxiliary bearing (40); and an eccentric bearing (42) provided on a movable scroll (24) of the compression section, wherein the rotary shaft has a main shaft (141) rotatably supported by the main bearing and the auxiliary bearing, inserted through the rotor and rotating integrally with the rotor, and an eccentric shaft (142) provided on the compression section side of the main shaft in the axial direction, eccentric with respect to the main shaft, and rotatably inserted into the eccentric bearing, wherein the main bearing is arranged between the rotor and the eccentric shaft in the axial direction, and the auxiliary bearing is arranged on the opposite side of the main bearing with respect to the main bearing in the axial direction, The compressor according to the sixth aspect, wherein the journal portion corresponds to at least one of a portion (141 a) of the main shaft portion inserted inside the main bearing portion, a portion (141 b) of the main shaft portion inserted inside the sub-bearing portion, and a portion (142 a) of the eccentric shaft portion inserted inside the eccentric bearing portion. [Eighth Aspect] The compressor according to any one of the first to seventh aspects, wherein the fluid compressed by the compression section is a hydrocarbon refrigerant or a carbon dioxide refrigerant.

Claims

1. A compressor comprising: a rotating shaft (14) having at least one journal portion (141a, 141b, 142a) and extending in an axial direction (Da, D1a, D2a); a compression portion (20) that compresses a fluid as the rotating shaft rotates; and at least one plain bearing portion (36, 40, 42) having one end portion (361, 401, 421) provided on one side in the axial direction, into which the journal portion is inserted, supporting the journal portion so as to be rotatable relative to the journal portion, and receiving a radial load (Fa, Fb, Fp) from the journal portion; the journal portion has a maximum diameter portion (141d, 141j, 142d) having the maximum diameter among the journal portions, and a crowning portion (141g, 141m, 142g) provided on one side in the axial direction with respect to the maximum diameter portion, facing the one end portion in a radial direction (D1r, D2r) of the journal portion and having a diameter that continuously decreases toward the one side in the axial direction, the crowning portion has a curved outer circumferential surface (141h, 141n, 142h) that is curved in a vertical cross section including an axis (Ca, Cb) of the journal portion and is continuously connected to the outer circumferential surface (141e, 141k, 142e) of the maximum diameter portion, and the journal portion is inclined with respect to the plain bearing portion, and a reaction force (Fca, Fcb, Fcp) of the plain bearing portion that opposes the radial load is received by the curved outer circumferential surface.

2. The compressor according to claim 1, wherein said curved outer peripheral surface is in the shape of a circular arc having a constant radius of curvature (Ra, Rb, Rp) in said longitudinal cross section.

3. A compressor as described in claim 1 or 2, wherein in the axial direction, a curved range (Wa1, Wb1, Wp1) in which the curved outer peripheral surface is formed is larger than a range (Wa2, Wb2, Wp2) obtained by excluding the curved range from the range (Wa, Wb, Wp) occupied by the crowning portion.

4. A compressor as described in claim 1 or 2, wherein the crowning portion has a tapered surface (141i, 141o, 142i) provided on one side in the axial direction of the curved outer peripheral surface, and the tapered surface extends linearly at an angle to the axis in the longitudinal cross section and is continuously connected to the curved outer peripheral surface.

5. A compressor as described in claim 1 or 2, comprising a support (44) which is formed with a shaft insertion hole (441b) into which the rotating shaft is inserted and which rotatably supports the rotating shaft, the rotating shaft having a flange portion (143), the flange portion facing the support body in the axial direction, and a maximum outer diameter (Dmx) of the flange portion being larger than a diameter (Dmn) of the shaft insertion hole.

6. The compressor according to claim 1 or 2, wherein the compression section is of a scroll type.

7. An electric motor (30) having a rotor (31) arranged in line with the compression section in the axial direction and a stator (32) that rotates the rotating shaft together with the rotor, a main bearing section (36), a sub-bearing section (40), and an eccentric bearing section (42) provided on a movable scroll (24) of the compression section, the rotating shaft having a main shaft section (141) rotatably supported by the main bearing section and the sub-bearing section, inserted through the rotor and rotating integrally with the rotor, and an eccentric shaft section (142) provided on the compression section side in the axial direction with respect to the main shaft section, eccentric with respect to the main shaft section, and rotatably inserted into the eccentric bearing section, the main bearing section being arranged at a position between the rotor and the eccentric shaft section in the axial direction, the sub-bearing section being arranged on the opposite side of the main bearing section across the rotor in the axial direction, 7. The compressor according to claim 6, wherein the journal portion corresponds to at least any one of a portion (141 a) of the main shaft portion inserted inside the main bearing portion, a portion (141 b) of the main shaft portion inserted inside the sub-bearing portion, and a portion (142 a) of the eccentric shaft portion inserted inside the eccentric bearing portion.

8. The compressor according to claim 1 or 2, wherein the fluid compressed by the compression section is a hydrocarbon refrigerant or a carbon dioxide refrigerant.

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