EP4242460A1 - Scroll compressor - Google Patents

Abstract

A scroll compressor includes a fixed scroll including a fixed scroll wrap, an orbiting scroll including an orbiting scroll wrap, a main shaft including an eccentric shaft portion that is located at a first end of the main shaft and to which the orbiting scroll is attached, a rotary drive unit that rotates the main shaft to cause the orbiting scroll to orbit, a slider provided between the eccentric shaft portion of the main shaft and the orbiting scroll and included in a variable crank mechanism that adjusts a radius of orbital motion of the orbiting scroll, a frame fixed to the fixed scroll and supporting the fixed scroll and the orbiting scroll, and an Oldham ring that is provided between the frame and the orbiting scroll, prevents the orbiting scroll from rotating on an axis of the orbiting scroll, and converts rotational motion of the main shaft into orbital motion of the orbiting scroll. The fixed scroll wrap has a side portion that supports an orbiting-scroll centrifugal force that is a centrifugal force generated by the orbital motion of the orbiting scroll. The Oldham ring performs simple harmonic motion during the orbit of the orbiting scroll. The orbiting scroll orbits in an elliptical orbit having a minor axis and a major axis, and the direction along the minor axis of the orbit of the orbiting scroll coincides with the direction of the simple harmonic motion of the Oldham ring.

Description

Technical Field
• The present disclosure relates to a scroll compressor, and in particular, relates to a scroll compressor that is used as a component of a refrigeration cycle circuit included in, for example, an air-conditioning apparatus or a refrigeration apparatus.
Background Art
• Some scroll compressors have a variable crank mechanism that adjusts the radius of orbital motion of an orbiting scroll. An existing scroll compressor having the variable crank mechanism includes an Oldham ring to prevent the orbiting scroll from rotating on its own axis. Once a combination of the orbiting scroll and a fixed scroll is determined, the radius of orbital motion of the orbiting scroll is substantially constant during each orbital motion (see Patent Literature 1, for example).
Citation List Patent Literature
• Patent Literature 1: Japanese Unexamined Patent Application Publication No. 2015-105632 (page 11 and Fig. 1)
Summary of Invention Technical Problem
• In the scroll compressor disclosed in Patent Literature 1, as described above, once a combination of the orbiting scroll and the fixed scroll is determined, the radius of orbital motion of the orbiting scroll is substantially constant during each orbital motion regardless of phase (angle of circumference). The Oldham ring performs simple harmonic motion only in a fixed radius direction. Therefore, an effect of the simple harmonic motion of the Oldham ring greatly varies from one phase for measurement of vibration (hereinafter referred to as a "vibration measurement phase") to another. As a result, it is not possible to reduce an imbalance caused by the simple harmonic motion of the Oldham ring. The imbalance leads to vibration of the scroll compressor.
• The present disclosure is applied to solve the above problem, and relates to a scroll compressor capable of reducing occurrence of vibration.
Solution to Problem
• A scroll compressor according to an embodiment of the present disclosure includes: a fixed scroll including a fixed scroll bedplate formed in the shape of a plate and a fixed scroll wrap formed in the shape of a wall body and protruding from a first surface of the fixed scroll bedplate; an orbiting scroll including an orbiting scroll bedplate formed in the shape of a plate and an orbiting scroll wrap formed in the shape of a wall body and protruding from a first surface of the orbiting scroll bedplate, the orbiting scroll being configured to compress fluid in a compression chamber that is defined by a combination of the fixed scroll wrap and the orbiting scroll wrap; a main shaft provided at a second surface of the orbiting scroll bedplate that is located opposite to the first surface of the orbiting scroll bedplate, the main shaft including an eccentric shaft portion that is located at a first end of the main shaft and to which the orbiting scroll is attached; a slider provided between the eccentric shaft portion of the main shaft and the orbiting scroll, the slider being included in a variable crank mechanism configured to adjust a radius of orbital motion of the orbiting scroll; a rotary drive unit configured to rotate the main shaft to cause the orbiting scroll to orbit; a frame fixed to the fixed scroll and supporting the fixed scroll and the orbiting scroll; and an Oldham ring provided between the frame and the orbiting scroll, and configured to prevent the orbiting scroll from rotating on an axis of the orbiting scroll and convert rotational motion of the main shaft into orbital motion of the orbiting scroll. The fixed scroll wrap has a side portion that supports an orbiting-scroll centrifugal force that is a centrifugal force generated by the orbital motion of the orbiting scroll. The Oldham ring performs simple harmonic motion during the orbital motion of the orbiting scroll. The orbiting scroll orbits in an elliptical orbit having a minor axis and a major axis. The direction along the minor axis of the orbit of the orbiting scroll coincides with the direction of the simple harmonic motion of the Oldham ring.
Advantageous Effects of Invention
• The scroll compressor according to the embodiment of the present disclosure is configured such that the orbiting scroll orbits in the elliptical orbit and the minor axis of the orbit of the orbiting scroll coincides with the direction of the simple harmonic motion of the Oldham ring. By virtue of such a configuration, it is possible to reduce an imbalance that is caused by the simple harmonic motion of the Oldham ring, thus reducing vibration of the scroll compressor.
Brief Description of Drawings
• [Fig. 1] Fig. 1 is a vertical sectional view of an example of the configuration of a scroll compressor 100 according to Embodiment 1.
• [Fig. 2] Fig. 2 is an explanatory view for an orbit in which an orbiting scroll orbits and the direction of simple harmonic motion of an Oldham ring in the scroll compressor 100 according to Embodiment 1.
• [Fig. 3] Fig. 3 is an explanatory view illustrating a slider 32 and an eccentric shaft portion 8a of a main shaft 8 of a scroll compressor 100 according to Embodiment 2.
• [Fig. 4] Fig. 4 is a plan view illustrating the shape of a fixed scroll wrap 1a and the shape of an orbiting scroll wrap 2a of a scroll compressor 100 according to Embodiment 3.
• [Fig. 5] Fig. 5 is a diagram indicating how an imbalance of the scroll compressor 100 according to Embodiment 3 is reduced.
• [Fig. 6] Fig. 6 is a plan view illustrating the shape of a fixed scroll wrap 1a and the shape of an orbiting scroll wrap 2a of a scroll compressor 100 according to Embodiment 4.
• [Fig. 7] Fig. 7 is a diagram indicating how an imbalance of the scroll compressor 100 according to Embodiment 4 is reduced.
• [Fig. 8] Fig. 8 is a plan view illustrating the shape of a fixed scroll wrap 1a and the shape of an orbiting scroll wrap 2a of a scroll compressor 100 according to Embodiment 5.
• [Fig. 9] Fig. 9 is a diagram indicating how an imbalance of the scroll compressor 100 according to Embodiment 5 is reduced.
• [Fig. 10] Fig. 10 is a top view of an example of the configuration of an Oldham ring 6 in Embodiment 1.
• [Fig. 11] Fig. 11 is a top view of an example of the configuration of a frame 19 in Embodiment 1.
• [Fig. 12] Fig. 12 is a bottom view of an example of the configuration of an orbiting scroll 2 in Embodiment 1.
• [Fig. 13] Fig. 13 is a diagram illustrating an orbital path 50P in a related-art scroll compressor.
• [Fig. 14] Fig. 14 is an explanatory view for parameters of the scroll compressor 100 according to Embodiment 3.
• [Fig. 15] Fig. 15 is an explanatory view indicating parameters of the scroll compressor 100 according to Embodiment 3.
Description of Embodiments
• A scroll compressor according to each of embodiments of the present disclosure will be described with reference to the drawings. In the present disclosure, descriptions concerning the embodiments are not limiting, and various modifications can be made without departing from the gist of the present disclosure. The present disclosure encompasses all possible combinations of components in the embodiments and modifications thereof. It should be noted that in each of figures which will be referred to below, components that are the same as or equivalent to those in a previous figure or previous figures are denoted by the same reference signs, and the same is true of the entire text of the specification. Relationships between the relative dimensions, shapes or other conditions of components in the figures may differ from actual ones.
Embodiment 1
• Fig. 1 is a vertical sectional view of an example of the configuration of a scroll compressor 100 according to Embodiment 1. Fig. 2 is an explanatory view for the orbit in which an orbiting scroll orbits, that is, the orbital path of the orbiting scroll, and the direction of simple harmonic motion of an Oldham ring in the scroll compressor 100 according to Embodiment 1. In Fig. 1, hatching of some components is omitted for simplification of the figure.
• The configuration of the scroll compressor 100 according to Embodiment 1 will be described with reference to Fig. 1. The scroll compressor 100 is used as a component of a refrigeration cycle circuit that is included in various industrial machines, such as a refrigerator, a freezer, a vending machine, an air-conditioning apparatus, a refrigeration apparatus, and a water heater.
• The scroll compressor 100 sucks refrigerant that circulates in the refrigeration cycle circuit, compresses the refrigerant to change it into high-temperature and high-pressure refrigerant, and discharges the high-temperature and high-pressure refrigerant. As illustrated in Fig. 1, the scroll compressor 100 includes a hermetic container 23 made up of a center shell 7, an upper shell 21, and a lower shell 22. The scroll compressor 100 further includes, in the hermetic container 23, a compression mechanism unit 40 including a combination of a fixed scroll 1 and an orbiting scroll 2 that orbits relative to the fixed scroll 1. In addition, the scroll compressor 100 includes, in the hermetic container 23, a rotary drive unit 41 including an electric rotary machine. As illustrated in Fig. 1, the compression mechanism unit 40 is located in an upper portion of the hermetic container 23, and the rotary drive unit 41 is located in a lower portion of the hermetic container 23.
• The hermetic container 23 is vertically long and cylindrical, and an upper end and a lower end of the hermetic container 23 are closed. The hermetic container 23 includes the center shell 7, the upper shell 21, and the lower shell 22 as described above; and the center shell 7 is cylindrical, the upper shell 21 is fixed to an upper end of the center shell 7, and the lower shell 22 is fixed to a lower end of the center shell 7. The lower shell 22 serves as an oil sump that stores lubricating oil for lubricating sliding part of the scroll compressor 100. The center shell 7 is connected to a suction pipe 14 for suction of refrigerant gas. The upper shell 21 is connected to a discharge pipe 16 for discharge of the refrigerant gas. The center shell 7 has a low-pressure chamber 17 therein, and the upper shell 21 has a high-pressure chamber 18 therein.
• The fixed scroll 1 includes a fixed scroll bedplate 1b and a fixed scroll wrap 1a. The fixed scroll bedplate 1b is disc-shaped or substantially disc-shaped. The fixed scroll wrap 1a is a scroll wrap that protrudes from one surface (first surface) of the fixed scroll bedplate 1b. The first surface is a lower surface of the fixed scroll bedplate 1b. The fixed scroll wrap 1a is a wall body that, as viewed in plan view, spirally extends outward from a location close to the center of the fixed scroll bedplate 1b in a radial direction of the fixed scroll bedplate 1b (see, for example, Fig. 4). The fixed scroll wrap 1a is formed in the shape of a wall body, and thus has a distal end face (that is, a lower end face) located parallel to the first surface of the fixed scroll bedplate 1b and side portions located between the distal end face and the first surface of the fixed scroll bedplate 1b. As illustrated in, for example, Fig. 4, the side portions include an inwardly facing surface 1aa and an outwardly facing surface 1ab. The side portions of the fixed scroll wrap 1a have a substantially constant height.
• The orbiting scroll 2 includes an orbiting scroll bedplate 2b and an orbiting scroll wrap 2a. The orbiting scroll bedplate 2b is disc-shaped or substantially disc-shaped. The orbiting scroll wrap 2a is a scroll wrap that protrudes from one surface (first surface) of the orbiting scroll bedplate 2b. The first surface is an upper surface of the orbiting scroll bedplate 2b. The orbiting scroll wrap 2a is a wall body that, as viewed in plan view, spirally extends outward from a location close to the center of the orbiting scroll bedplate 2b in a radial direction of the orbiting scroll bedplate 2b and that is provided to mesh with the fixed scroll wrap 1a of the fixed scroll 1 (see, for example, Fig. 4). The orbiting scroll wrap 2a is formed in the shape of a wall body, and thus has a distal end face (that is, an upper end face) located parallel to the first surface of the orbiting scroll bedplate 2b and side portions located between the distal end face and the first surface of the orbiting scroll bedplate 2b. As illustrated in, for example, Fig. 4, the side portions include an inwardly facing surface 2aa and an outwardly facing surface 2ab. The side portions of the orbiting scroll wrap 2a have a substantially constant height. The other surface of the orbiting scroll bedplate 2b, that is, a second surface thereof that is opposite to the first surface from which the orbiting scroll wrap 2a protrudes, serves as an orbiting scroll thrust bearing surface 2c.
• The orbiting scroll 2 and the fixed scroll 1 are accommodated in a frame 19. As illustrated in Fig. 1, the frame 19 is substantially T-shaped as viewed side-on, and the outside diameter of an upper portion of the frame 19 is larger than that of a lower portion of the frame 19. The frame 19 has open upper and lower ends, and is hollow. The frame 19 fixes the fixed scroll 1. The frame 19 has a refrigerant suction port through which refrigerant (fluid) sucked from the suction pipe 14 is guided into the compression mechanism unit 40.
• The frame 19 further has a thrust surface that axially supports a thrust bearing load that is applied during operation of the scroll compressor 100. The thrust bearing load acts on the orbiting scroll 2. The orbiting scroll 2 is supported by the frame 19 such that the orbiting scroll thrust bearing surface 2c is in contact with the thrust surface of the frame 19. A thrust plate 3 is provided between the thrust surface of the frame 19 and the orbiting scroll thrust bearing surface 2c in order to improve sliding performance.
• The orbiting scroll 2 and the fixed scroll 1 are mounted in the hermetic container 23 such that the orbiting scroll wrap 2a and the fixed scroll wrap 1a are combined with each other. The orbiting scroll wrap 2a is eccentrically combined with the fixed scroll wrap 1a. When the orbiting scroll 2 and the fixed scroll 1 are combined together, the fixed scroll wrap 1a and the orbiting scroll wrap 2a spiral in opposite directions. The orbiting scroll wrap 2a and the fixed scroll wrap 1a define a compression chamber 24 that changes in relative volume. The orbiting scroll 2 orbits to form the compression chamber 24 on a suction side adjacent to the outside, move the compression chamber 24 toward the center, and discharge the refrigerant compressed in the compression chamber 24 through a discharge port 15. It should be noted that in order to reduce occurrence of a leak of the refrigerant from the distal end face (that is, the lower end face) of the fixed scroll wrap 1a of the fixed scroll 1, a seal 25 is provided at the distal end face of the fixed scroll wrap 1a. Similarly, in order to reduce occurrence of a leak of the refrigerant from the distal end face (that is, the upper end face) of the orbiting scroll wrap 2a of the orbiting scroll 2, a seal 26 is provided at the distal end face of the orbiting scroll wrap 2a. The fixed scroll wrap 1a and the orbiting scroll wrap 2a have basically the same shape, but may differ from each other in details of the shape.
• The fixed scroll 1 is fixed to the frame 19 by a bolt, for example. The fixed scroll bedplate 1b of the fixed scroll 1 has the discharge port 15, through which high-pressure refrigerant gas obtained through compression is discharged, and which is formed at a central portion of the fixed scroll bedplate 1b. The above high-pressure refrigerant gas is discharged into the high-pressure chamber 18 located above the fixed scroll 1. The refrigerant gas discharged into the high-pressure chamber 18 is discharged to the refrigeration cycle circuit through the discharge pipe 16. It should be noted that a discharge valve 27, which prevents backflow of the refrigerant from the high-pressure chamber 18 toward the discharge port 15, is located at the discharge port 15.
• The orbiting scroll 2 includes an Oldham ring 6, which prevents the orbiting scroll 2 from rotating on its own axis and causes the orbiting scroll 2 to orbit. Because of the action of the Oldham ring 6, the orbiting scroll 2 orbits relative to the fixed scroll 1 without rotating on its own axis. At substantially the center of the second surface of the orbiting scroll 2, a hollow cylindrical boss 2d is formed. The main shaft 8 has an eccentric shaft portion 8a located at an upper end (first end) thereof. The eccentric shaft portion 8a is inserted in the boss 2d, with a slider 32 interposed between the eccentric shaft portion 8a and the boss 2d.
• The Oldham ring 6 is provided between the frame 19 and the orbiting scroll 2. Fig. 10 is a top view of an example of the configuration of the Oldham ring 6 in Embodiment 1. Fig. 11 is a top view of an example of the configuration of the frame 19 in Embodiment 1. Fig. 12 is a bottom view of an example of the configuration of the orbiting scroll 2 in Embodiment 1. As illustrated in Fig. 10, the Oldham ring 6 includes an annular ring portion 6b. At a lower surface of the ring portion 6b of the Oldham ring 6, a pair of Oldham keys 6ac are formed as illustrated in Figs. 1 and 10. The Oldham keys 6ac are protrusions that protrude from the lower surface of the ring portion 6b. The Oldham keys 6ac are arranged symmetrically with reference to the center of a region where the ring portion 6b is located. The Oldham keys 6ac are fitted in Oldham key grooves 5 formed in the frame 19. At an upper surface of the ring portion 6b of the Oldham ring 6, a pair of Oldham keys 6ab are formed as illustrated in Figs. 1 and 10. The Oldham keys 6ab are protrusions that protrude from the upper surface of the ring portion 6b. The Oldham keys 6ab are arranged symmetrically with reference to the center of the region where the ring portion 6b is located. The Oldham keys 6ab are fitted in Oldham key grooves 4 formed in the orbiting scroll 2. Each of the Oldham keys 6ac is displaced in phase from an associated adjacent one of the Oldham keys 6ab by, for example, 90 degrees.
• As illustrated in Fig. 11, the frame 19 has the pair of Oldham key grooves 5 which extend in the radial direction. The Oldham key grooves 5 are arranged symmetrically with reference to the center of a region where the frame 19 is located. The frame 19 is formed to have an Oldham ring space 19c. In the Oldham ring space 19c, the Oldham ring 6 is accommodated. The Oldham ring 6 is reciprocated within the Oldham ring space 19c.
• In the orbiting scroll thrust bearing surface 2c, which is the lower surface of the orbiting scroll 2, the pair of Oldham key grooves 4 are formed to extend in the radial direction as illustrated in Fig. 12. The Oldham key grooves 4 are arranged symmetrically with reference to the center of the orbiting scroll 2.
• The Oldham keys 6ac and 6ab of the Oldham ring 6 are fitted in the Oldham key grooves 5 of the frame 19 and the Oldham key grooves 4 of the orbiting scroll 2, respectively. In this state, the Oldham keys 6ac and 6ab of the Oldham ring 6 transmit a rotational force generated by the rotary drive unit 41 to the orbiting scroll 2, which is orbiting, while moving back and forth over sliding surfaces formed in the Oldham key grooves 5 and 4, which are filled with a lubricant. In such a manner, the Oldham ring 6 converts rotational motion of the main shaft 8 into orbital motion of the orbiting scroll 2. It should be noted that during operation of the scroll compressor 100, the Oldham ring 6 perform a simple harmonic action in a direction along the Oldham key grooves 5 of the frame 19, that is, a direction indicated by arrows A in Fig. 11. Hereinafter, the direction of the arrows A will be referred to as a simple harmonic motion direction of the Oldham ring 6.
• Re-referring to Fig. 1, the rotary drive unit 41 includes the main shaft 8 which is a rotary shaft, the rotor 11 fixed to the main shaft 8, and the stator 10 which is cylindrical and provided circumferentially and outward of the rotor 11. The axial direction of the main shaft is, for example, a vertical direction. The rotor 11 is shrink-fitted to the main shaft 8. When power supply to the stator 10 is started, the rotor 11 is driven to rotate, thus rotating the main shaft 8. That is, the stator 10 and the rotor 11 form an electric rotary machine (motor). The stator 10 is shrink-fitted to the center shell 7. A first balance weight 12 is fixed to the main shaft 8. The rotor 11 and the stator 10 are located below the first balance weight 12 fixed to the main shaft 8. The stator 10 is supplied with power via a power supply terminal 9 located at the center shell 7.
• The main shaft 8 is rotated in accordance with rotation of the rotor 11 to cause the orbiting scroll 2 to orbit. A portion of the main shaft 8 that is located in the vicinity of the eccentric shaft portion 8a, that is, an upper portion of the main shaft 8, is supported by a main bearing 20 located in the frame 19. A lower portion of the main shaft 8 is supported by a sub-bearing 29 such that the main shaft 8 is rotatable. The sub-bearing 29 is press-fitted in a bearing accommodation portion located at a central portion of a sub-frame 28 located in the lower portion of the hermetic container 23. At the sub-frame 28, a positive-displacement oil pump 30 is provided. Lubricating oil sucked by the oil pump 30 is supplied to sliding portions through an oil supply hole 31 formed in the main shaft 8.
• The eccentric shaft portion 8a is located at the upper end of the main shaft 8. The slider 32, which is slidable relative to the eccentric shaft portion 8a, is attached to the eccentric shaft portion 8a. As described above, at substantially the central portion of the second surface of the orbiting scroll 2, the hollow and cylindrical boss 2d is provided. In the boss 2d, the eccentric shaft portion 8a of the main shaft 8 is inserted, with the slider 32 interposed between the boss 2d and the eccentric shaft portion 8a. Therefore, an inner wall of the boss 2d serves as an orbiting-scroll bearing. The slider 32 is fitted in the boss 2d, thus forming a variable crank mechanism. An orbiting-scroll centrifugal force that is a centrifugal force generated by the orbital motion of the orbiting scroll 2 is supported by the side portions of the fixed scroll wrap 1a of the fixed scroll 1. The variable crank mechanism flexibly adjusts the radius of orbital motion of the orbiting scroll 2. As described above, the orbiting scroll 2 is eccentrically supported by the upper portion of the main shaft 8.
• In addition, at the upper portion of the main shaft 8, the first balance weight 12 is provided. For example, as illustrated in Fig. 1, the first balance weight 12 is provided at a portion of the main shaft 8 that is located at a higher position than an axially central portion of the main shaft 8. The first balance weight 12 is provided at the main shaft 8 to cancel an imbalance that is caused by the orbital motion of the orbiting scroll 2. Furthermore, a second balance weight 13 is provided at a lower portion of the rotor 11 to cancel an imbalance that is caused by the orbital motion of the orbiting scroll 2. The first balance weight 12 is fixed to the upper portion of the main shaft 8 by shrink-fitting. The second balance weight 13 is fixed to the lower portion of the rotor 11 such that the second balance weight 13 is provided integral with the rotor 11.
• Next, an operation of the scroll compressor 100 will be described.
• When power is supplied to the power supply terminal 9, current flows through wires of the stator 10, thus generating a magnetic field. This magnetic field acts to rotate the rotor 11. That is, torque is generated at the stator 10 and the rotor 11, and the rotor 11 is thus rotated. As the rotor 11 is rotated, the main shaft 8 is driven to rotate. As the main shaft 8 is rotated, the orbiting scroll 2 performs orbital motion while being prevented by the action of the Oldham ring 6 from rotating on its own axis.
• As described above, the first balance weight 12 is fixed to the upper portion of the main shaft 8, and the second balance weight 13 is fixed to the lower portion of the rotor 11. When the rotor 11 is rotated, the orbital motion of the orbiting scroll 2, the slider 32, and the eccentric shaft portion 8a of the main shaft 8 and the simple harmonic motion of the Oldham ring 6 are kept balanced by the first balance weight 12 and the second balance weight 13. Thus, the orbiting scroll 2 which is eccentrically supported by the upper portion of the main shaft 8 and prevented by the Oldham ring 6 from rotating on its own axis starts performing the orbital motion, whereby the refrigerant is compressed based on a well-known compression principle.
• Thus, part of refrigerant gas flows into the compression chamber 24 through the frame refrigerant suction port of the frame 19, and a suction process starts. Part of remaining refrigerant gas passes through a cutout (not illustrated) of a steel plate of the stator 10 and cools the electric rotary machine (motor) and the lubricating oil. The compression chamber 24 is moved toward the center of the orbiting scroll 2 by the orbital motion of the orbiting scroll 2 and the volume of the compression chamber 24 is thus further reduced. By this process, the refrigerant gas in the compression chamber 24 is compressed. The compressed refrigerant passes through the discharge port 15 of the fixed scroll 1, pushes the discharge valve 27 to open the discharge valve 27, and flows into the high-pressure chamber 18. The refrigerant is then discharged from the hermetic container 23 through the discharge pipe 16.
• A thrust bearing load generated by the pressure of the refrigerant gas in the compression chamber 24 is a force that acts downward in Fig. 1, and is thus received by the frame 19 which supports the orbiting scroll thrust bearing surface 2c. Furthermore, a centrifugal force and a refrigerant gas load that are generated by rotation of the main shaft 8 and act on the first balance weight 12 and the second balance weight 13 are received by the main bearing 20 and the sub-bearing 29. The low-pressure chamber 17 and the high-pressure chamber 18 are partitioned off and separated from each other by the fixed scroll 1 and the frame 19, and are kept hermetically sealed. Thus, the low-pressure chamber 17 and the high-pressure chamber 18 are hermetically sealed by the fixed scroll 1 and the frame 19, respectively, thereby preventing low pressure refrigerant gas in the low-pressure chamber 17 and high-pressure refrigerant gas in the high-pressure chamber 18 from flowing into the high-pressure chamber 18 and the low-pressure chamber 17, respectively. When power supply to the stator 10 is stopped, the scroll compressor 100 stops operating.
• Fig. 2 is the explanatory view for the orbit in which the orbiting scroll 2 orbits, that is, the orbital path of the orbiting scroll 2, and the direction of the simple harmonic motion of the Oldham ring in the scroll compressor 100 according to Embodiment 1. Advantages obtained in Embodiment 1 will be described with reference to Fig. 2.
• In the scroll compressor 100 according to Embodiment 1, as illustrated in Fig. 2, an orbital path 50 of the orbiting scroll 2 is an elliptical orbital path. Therefore, the orbital path 50 has a minor axis Rmin denoted by reference sign 51 and a major axis Rmax denoted by reference sign 52. The minor axis Rmin 51 is smaller than the major axis Rmax 52. The minor axis Rmin 51 and the major axis Rmax 52 intersect at a right angle at a center 53 of the orbital path 50, as illustrated in Fig. 2. In Embodiment 1, the orbiting scroll 2 performs the orbital motion along the orbital path 50, which is an elliptical orbital path (see, for example, Fig. 4).
• In Fig. 2, the minor axis Rmin extends along a Y-axis, and the major axis Rmax 52 extends along an X-axis. In Embodiment 1, as illustrated in Fig. 2, the direction of the simple harmonic motion of the Oldham ring 6, which is indicated by arrows A, is made to coincide with the direction along the Y-axis. As described above, in Embodiment 1, the extending direction of the minor axis Rmin of the orbital path 50 of the orbiting scroll 2 is made to coincide with the direction of the simple harmonic motion of the Oldham ring 6
• Since the scroll compressor 100 according to Embodiment 1 has the above configuration, it is possible to reduce an imbalance that is caused by the simple harmonic motion of the Oldham ring, whose effect varies depending on the vibration measurement phase, and thus to reduce vibration of the scroll compressor 100.
• In contrast, for example, in an existing scroll compressor described in Patent Literature 1, the orbital path of an orbiting scroll is a substantially circular orbital path, not an elliptical orbital path, as illustrated in Fig. 13. Fig. 13 is a diagram illustrating an orbital path 50P in the existing scroll compressor. As illustrated in Fig. 13, the orbital path 50P is substantially circular, and thus has a substantially constant radius Rp. In Fig. 13, arrows A indicates the direction of the simple harmonic motion of the Oldham ring. Despite the circular orbital path 50P of the orbiting scroll, the direction of the simple harmonic motion of the Oldham ring is kept along the Y-axis. Therefore, the effect of the simple harmonic motion of the Oldham ring varies depending on the vibration measurement phase. That is, the effect of the simple harmonic motion of the Oldham ring is the largest in the direction along the Y-axis and is the smallest in the direction along the X-axis. Thus, in the orbital path 50P, as a whole, the effect of the simple harmonic motion of the Oldham ring necessarily causes an imbalance at a phase at which the effect of the simple harmonic motion is significant. The imbalance leads to vibration of the scroll compressor.
• In Embodiment 1, in order to reduce such an imbalance as described above, the orbital path 50 of the orbiting scroll 2 is elliptical and the extending direction of the minor axis Rmin 51 of the orbital path 50 of the orbiting scroll 2 is made to coincide with the direction of the simple harmonic motion of the Oldham ring 6. In such a manner, since the direction of the simple harmonic motion of the Oldham ring 6 is made to coincide with the extending direction of the minor axis of the orbital path 50, it is possible to reduce the difference in effect of the simple harmonic motion of the Oldham ring 6 between vibration measurement phases. It is therefore possible to reduce an imbalance that is caused by the simple harmonic motion of the Oldham ring 6, whose effect varies depending on the vibration measurement phase, thereby reducing vibration of the scroll compressor 100.
Embodiment 2
• The entire configuration of a scroll compressor 100 according to Embodiment 2 is basically the same as the configuration as illustrated in Fig. 1 and described above regarding Embodiment 1. Accordingly, Embodiment 2 will be described with reference to Fig. 1, and descriptions concerning components in Embodiment 2 that have the same configurations as those in Embodiment 1 will be omitted. As described above with reference to Fig. 1, at the upper portion of the main shaft 8, the eccentric shaft portion 8a is provided. To the eccentric shaft portion 8a, the slider 32 is attached such that the slider 32 is slidable relative to the eccentric shaft portion 8a.
• Fig. 3 is an explanatory view illustrating the slider 32 and the eccentric shaft portion 8a of the main shaft 8 of the scroll compressor 100 according to Embodiment 2. A configuration in which the slider 32 and the eccentric shaft portion 8a of the main shaft 8 in Embodiment 2 are provided is basically the same as that in Embodiment 1. Fig. 3 illustrates a part of the eccentric shaft portion 8a that is fitted in the slider 32. As described above with reference to Fig. 1, the slider 32 is provided between the boss 2d and the eccentric shaft portion 8a, and is included in the variable crank mechanism which adjusts the radius of the orbital motion of the orbiting scroll 2 during orbital motion of the orbiting scroll 2. The slider 32 is loosely fitted to the eccentric shaft portion 8a such that the slider 32 is slidable relative to the eccentric shaft portion 8a, and is fitted in the boss 2d.
• As illustrated in Fig. 3, the slider 32 has a circular shape as viewed in plan view. The eccentric shaft portion 8a of the main shaft 8 has a rectangular shape having rounded opposite ends in the longitudinal direction of the eccentric shaft portion 8a or an elliptical shape as viewed in plan view. The slider 32 has an eccentric bearing portion 32a, in which the eccentric shaft portion 8a of the main shaft 8 is inserted, at a central portion of the slider 32. The eccentric bearing portion 32a has a rectangular shape having rounded opposite ends in the longitudinal direction of the eccentric bearing portion 32a or an elliptical shape as viewed in plan view. In the longitudinal direction of each of the eccentric bearing portion 32a and the eccentric shaft portion 8a of the main shaft 8, the eccentric bearing portion 32a is longer than the eccentric shaft portion 8a, as illustrated in Fig. 3. Therefore, the slider 32 is slidable relative to the eccentric shaft portion 8a in the longitudinal direction, that is, the direction indicated by arrows B in Fig. 3. Hereinafter, the direction indicated by the arrows B will be referred to as a sliding direction of the slider 32.
• In Embodiment 2, as illustrated in Fig. 3, the sliding direction of the slider 32 is made to coincide with the direction in which a centrifugal force on the orbiting scroll 2 acts. On this point, Embodiment 2 is different from Embodiment 1. On the other points, Embodiment 2 is the same as Embodiment 1. Specifically, in Embodiment 2, the direction of the simple harmonic motion of the Oldham ring 6 is made to coincide with the extending direction of the minor axis of the orbital path 50 of the orbiting scroll 2, and the sliding direction of the slider 32 is made to coincide with the direction in which the centrifugal force on the orbiting scroll 2 acts.
• Referring to Fig. 3, the direction in which the centrifugal force on the orbiting scroll 2 acts is a direction along a Z-axis, and a direction orthogonal to the Z-axis is a direction along a W-axis. During the orbital motion of the orbiting scroll 2, a centrifugal force on the orbiting scroll 2 is generated in the direction along the Z-axis. In Embodiment 2, as illustrated in Fig. 3, the sliding direction of the slider 32 as indicated by the arrows B is made to coincide with the direction along the Z-axis. In such a manner, in Embodiment 2, the sliding direction of the slider 32 is made to coincide with the direction of the centrifugal force on the orbiting scroll 2. Therefore, even in the case where a centrifugal force is generated in the direction along the Z-axis during the orbital motion of the orbiting scroll 2, the movement of the slider 32 in the direction along the W-axis orthogonal to the Z-axis is reduced. Therefore, in Embodiment 2, it is possible to reduce an imbalance in the direction along the W-axis during each orbital motion of the orbiting scroll 2.
• As described above, in Embodiment 2, as illustrated in Fig. 2, the direction (direction indicated by the arrows A) of the simple harmonic motion of the Oldham ring 6 is made to coincide with the extending direction of the minor axis Rmin of the orbital path 50 of the orbiting scroll 2, as in Embodiment 1. It is therefore possible to obtain the same advantages as in Embodiment 1.
• Furthermore, in Embodiment 2, as illustrated in Fig. 3, the sliding direction (direction indicated by the arrows B) of the slider 32 is made to coincide with the direction of the centrifugal force on the orbiting scroll 2. It is therefore possible to reduce an imbalance in the direction along the W-axis orthogonal to the direction of the centrifugal force on the orbiting scroll 2 during each orbital motion of the orbiting scroll 2. Thus, vibration of the scroll compressor 100 can be further reduced, as compared with Embodiment 1.
Embodiment 3
• Fig. 4 is a plan view illustrating the shape of the fixed scroll wrap 1a and the shape of the orbiting scroll wrap 2a of a scroll compressor 100 according to Embodiment 3.
• In Embodiment 3, the following limitations are added to the above configuration in Embodiment 1 or Embodiment 2. Specifically, each of the scroll wrap of the fixed scroll 1 and the scroll wrap of the orbiting scroll 2 has a shape that is expressed by Equations (1) and (2) described below. Each of the scrolls has a wrap thickness angle α expressed by Equation (3) described below. The scroll has a wrap thickness t expressed by Equation (4) described below. The orbital path 50 of the scroll which is the orbit in which the scroll orbits has a radius R, a minor axis Rmin, and a major axis Rma that are expressed by Equations (5), (6), and (7) described below, respectively. In this case, the scroll compressor 100 according to Embodiment 3 has a configuration in which the direction of the simple harmonic motion of the Oldham ring 6 is the direction along the Y-axis, and the minor axis Rmin, the major axis Rmax, and constants (W1, W2) satisfy a relationship expressed by Equation (8) described below, where W1 is the total mass of the orbiting scroll 2 and the slider 32, and W2 is the mass of the Oldham ring 6. $$\mathrm{x}=\mathrm{a}\times \left\{\cos \mathrm{\varphi +}\left(\mathrm{\varphi }\pm \mathrm{\alpha }\right)\sin \mathrm{\varphi }\right\}$$

  

  $$\mathrm{y}=\mathrm{a}\times \left\{\sin \mathrm{\varphi -}\left(\mathrm{\varphi }\pm \mathrm{\alpha }\right)\cos \mathrm{\varphi }\right\}$$

  

  $$\mathrm{\alpha }=\mathrm{<figure-callout\; id="1"\; label="\alpha "\; filenames="imgf0003.png,imgf0007.png"\; state="\{\{state\}\}">\alpha </figure-callout>}1+\mathrm{b}\times {\mathrm{<figure-callout\; id="2"\; label="cos"\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">cos</figure-callout>}}^2\mathrm{\varphi }$$

  

  $$\mathrm{t}=2\mathrm{a\alpha }$$

  

  $$\mathrm{R}=\mathrm{a}\times \left(\mathrm{\pi }-2\mathrm{\alpha }\right)$$

  

  $$\mathrm{Rmin}=\mathrm{a}\times \left\{\mathrm{\pi }-2\left(\mathrm{<figure-callout\; id="1"\; label="\alpha "\; filenames="imgf0003.png,imgf0007.png"\; state="\{\{state\}\}">\alpha </figure-callout>}1+\mathrm{b}\right)\right\}$$

  

  $$\mathrm{Rmax}=\mathrm{a}\times \left(\mathrm{\pi }-2\mathrm{<figure-callout\; id="1"\; label="\alpha "\; filenames="imgf0003.png,imgf0007.png"\; state="\{\{state\}\}">\alpha </figure-callout>}1\right)$$

  

  $$\mathrm{Rmax}\times \mathrm{<figure-callout\; id="1"\; label="W"\; filenames="imgf0003.png,imgf0007.png"\; state="\{\{state\}\}">W</figure-callout>}1=\mathrm{Rmin}\times \left(\mathrm{<figure-callout\; id="1"\; label="W"\; filenames="imgf0003.png,imgf0007.png"\; state="\{\{state\}\}">W</figure-callout>}1+\mathrm{<figure-callout\; id="2"\; label="W"\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">W</figure-callout>}2\right)$$

  
• Parameters in Equations (1) to (8) are defined as follows:
• a is a base circle radius of the scroll (constant);
• b is a constant (b > 0);
• α1 is a reference wrap thickness angle of the scroll (constant);
• φ is an involute angle of the scroll (parameter variable);
• α is the wrap thickness angle of the scroll (variable with φ as a parameter, α < 0.5
• π); t is the wrap thickness of the scroll (variable with φ as a parameter);
• R is the radius of the orbit in which the orbiting scroll orbits, that is, the orbital path of the orbiting scroll (variable with φ as a parameter);
• Rmin is the minor axis of the orbit in which the orbiting scroll orbits (constant);
• Rmax: the major axis of the orbit in which the orbiting scroll orbits (constant);
• W1 is the total mass of the orbiting scroll and the slider (constant); and
• W2 is the mass of the Oldham ring (constant).
• When Equation (8) is transformed, the following relationship is established. $$\mathrm{Rmin}:\mathrm{Rmax}=\mathrm{W}1:\left(\mathrm{<figure-callout\; id="1"\; label="W"\; filenames="imgf0003.png,imgf0007.png"\; state="\{\{state\}\}">W</figure-callout>}1+\mathrm{<figure-callout\; id="2"\; label="W"\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">W</figure-callout>}2\right)$$

  
• In other words, in Embodiment 3, the ratio between the minor axis Rmin and the major axis Rmax is equal to the ratio between the total mass W1 of the orbiting scroll 2 and the slider 32 and the total mass (= W1 + W2) of the orbiting scroll 2, the slider 32, and the Oldham ring 6.
• In Embodiment 3, the other configurations and operations are the same as those in Embodiment 1 or Embodiment 2, and their descriptions will thus be omitted.
• By virtue of the above configuration, it is possible to reduce an imbalance that is caused by the simple harmonic motion of the Oldham ring 6, whose effect varies depending on the vibration measurement phase, thereby reducing vibration of the scroll compressor 100.
• Fig. 5 is a diagram indicating how an imbalance of the scroll compressor 100 according to Embodiment 3 is reduced. In Fig. 5, the horizontal axis represents the vibration measurement phase θ, and the vertical axis represents a balance amount. Also, in Fig. 5, a broken line Up represents a graph indicating the balance amount in the related art described in, for example, Patent Literature 1, and a solid line Ua represents a graph indicating the balance amount in Embodiment 3. As illustrated in Fig. 5, each of the balance amounts Up and Ua varies depending on the vibration measurement phase θ. Specifically, for example, the balance amount Up reaches a maximum value (peak) at vibration measurement phases θ of 0,180, and 360 degrees, and reaches a minimum value at vibration measurement phases θ of 90 and 270 degrees. Also, in the balance amount Ua in Embodiment 3, the balance amount increases or decreases as the vibration measurement phase θ changes. However, from comparison between the peak values, it can be seen that the advantage of Embodiment 3 is remarkable. Specifically, as indicated in Fig. 5, the peak value of the balance amount Ua in Embodiment 3 is approximately 1/4 of the peak value of the balance amount Up in the related art. In such a manner, it can be seen that in Embodiment 3, that fluctuation of the balance amount, which varies depending on the vibration measurement phase, that is, the amount of imbalance, is greatly reduced.
• The parameters in Equations (1) to (8) described above will be described in brief. Figs. 14 and 15 are explanatory views indicating the parameters of the scroll compressor 100 according to Embodiment 3. In general, it is known that an involute of a regular polygon or a circle is used for a curve that defines a scroll wrap of a scroll compressor. In Embodiment 3, as illustrated in Fig. 14, a curve defining each of the fixed scroll wrap 1a and the orbiting scroll wrap 2a of the scroll compressor 100 is designed based on an involute 60 of a circle. The involute 60 of the circle is a curve that includes a plurality of arcs connected together and continuously changes in curvature. The involute 60 of the circle is defined in the XY coordinate system with the involute angle φ as a parameter in Fig. 14. A circle having a radius a as indicated in Fig. 14 will be referred to as a base circle 62 of the involute 60 or the base circle 62 of the scroll. The radius a is called a base circle radius.
• Fig. 15 is an explanatory view illustrating the way of obtaining coordinates of the involute. Fig. 15, (a), illustrates the involute 60 and the base circle 62 as illustrated in Fig. 14. Fig. 15, (b), illustrates an inwardly facing surface 63 and an outwardly facing surface 64 that extend, with the involute 60 located as a center line between the inwardly facing surface 63 and the outwardly facing surface 64. In general, the wrap thickness angle α of the scroll is illustrated as in Fig. 15, (b), and is a parameter that defines the wrap thickness of the scroll. Specifically, as illustrated in Fig. 15, (b), an angle between the X-axis and a straight line connecting the intersection of the base circle 62 and the inwardly facing surface 63 to the center of the base circle 62 or an angle between the X-axis and a straight line connecting the intersection of the base circle 62 and the outwardly facing surface 64 to the center of the base circle 62 is referred to as the wrap thickness angle α. The wrap thickness angle α in Embodiment 3 is a variable with the involute angle φ as a parameter based on the concept of the typical wrap thickness angle α as illustrated in Fig. 15, (b), and is defined by Equation (3) described above.
• Furthermore, as illustrated in Figs. 4 and 15, the orbiting scroll wrap 2a of the orbiting scroll 2 has a thickness. This thickness is referred to as the wrap thickness t of the orbiting scroll 2. The wrap thickness t is not a constant value but a variable with the involute angle φ as a parameter, and is expressed by Equation (4) described above. The minor axis Rmin 51 (see Fig. 2) and the major axis Rmax 52 (see Fig. 2) of the orbital path 50 of the orbiting scroll 2 in Embodiment 3 are respectively expressed by Equations (6) and (7) described above. The radius R (see Fig. 2) of the orbital path 50 is a variable with the involute angle φ as a parameter, and is expressed by Equation (5) described above. The sum of the mass of the orbiting scroll 2 and the mass of the slider 32 is referred to as the total mass W1. The mass of the Oldham ring 6 is referred to as the mass W2. Although the above description is made by referring mainly to parameters for part of the orbiting scroll wrap 2a, the parameters may be set for associated part of the fixed scroll wrap 1a.
• As described above, in Embodiment 3, as in Embodiment 1, the orbital path 50 of the orbiting scroll 2 is elliptical, and the minor axis Rmin 51 of the orbital path 50 of the orbiting scroll 2 is made to coincide with the direction of the simple harmonic motion of the Oldham ring 6. Thus, the same advantages as in Embodiment 1 are obtained.
• In Embodiment 3, as in Embodiment 2, the sliding direction (direction indicated by arrows B) of the slider 32 may be coincided with the direction of the centrifugal force on the orbiting scroll 2. In this case, the same advantages as in Embodiment 2 can further be obtained.
• In addition, the scroll compressor 100 according to Embodiment 3 has a configuration that satisfies Equations (1) to (8) described above. By virtue of such a configuration, in Embodiment 3, it is possible to greatly reduce an imbalance that is caused by the simple harmonic motion of the Oldham ring 6, whose effect varies depending on the vibration measurement phase, as compared with the related art, as illustrated in Fig. 5, thus greatly reducing vibration of the scroll compressor 100.
Embodiment 4
• Fig. 6 is a plan view illustrating the shape of the fixed scroll wrap 1a and the shape of the orbiting scroll wrap 2a of a scroll compressor 100 according to Embodiment 4.
• In Embodiment 4, the following limitations are added to the above configuration of Embodiment 1 or Embodiment 2. Specifically, each of the scroll wrap of the fixed scroll 1 and the scroll wrap of the orbiting scroll 2 has a shape expressed by Equations (9) and (10) described below. Each of the scrolls has a base circle radius a expressed by Equation (11) described below. The scroll has a wrap thickness t expressed by Equation (12) described below. The orbital path 50 of the orbiting scroll 2 has a radius R, a minor axis Rmin, and a major axis Rmax that are expressed by Equations (13), (14), and (15) described below, respectively. The scroll compressor 100 according to Embodiment 4 has a configuration in which the direction of the simple harmonic motion of an Oldham ring 6 is the direction along the Y-axis, and the minor axis Rmin, the major axis Rmax, and the constants (W1, W2) satisfy a relationship expressed by Equation (16) described below, where W1 is the total mass of the orbiting scroll 2 and the slider 32, and W2 is the mass of the Oldham ring 6, as in Embodiment 3. $$\mathrm{x}=\mathrm{a}\times \left\{\cos \mathrm{\varphi +}\left(\mathrm{\varphi }\pm \mathrm{\alpha }\right)\sin \mathrm{\varphi }\right\}$$

  

  $$\mathrm{y}=\mathrm{a}\times \left\{\sin \mathrm{\varphi }\left(\mathrm{\varphi }\pm \mathrm{\alpha }\right)\cos \mathrm{\varphi }\right\}$$

  

  $$\mathrm{a}=\mathrm{a}1+\mathrm{b}\times {\mathrm{<figure-callout\; id="2"\; label="sin"\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">sin</figure-callout>}}^2\mathrm{\varphi }$$

  

  $$\mathrm{t}=2\mathrm{a\alpha }$$

  

  $$\mathrm{R}=\mathrm{a}\times \left(\mathrm{\pi }-2\mathrm{\alpha }\right)$$

  

  $$\mathrm{Rmin}=\mathrm{a}1\times \left(\mathrm{\pi }-2\mathrm{\alpha }\right)$$

  

  $$\mathrm{Rmax}=\left(\mathrm{a}1+\mathrm{b}\right)\times \left(\mathrm{\pi }-2\mathrm{\alpha }\right)$$

  

  $$\mathrm{Rmax}\times \mathrm{<figure-callout\; id="1"\; label="W"\; filenames="imgf0003.png,imgf0007.png"\; state="\{\{state\}\}">W</figure-callout>}1=\mathrm{Rmin}\times \left(\mathrm{<figure-callout\; id="1"\; label="W"\; filenames="imgf0003.png,imgf0007.png"\; state="\{\{state\}\}">W</figure-callout>}1+\mathrm{<figure-callout\; id="2"\; label="W"\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">W</figure-callout>}2\right)$$

  
• Parameters in Equations (9) to (16) are defined as follows:
• a1 is a reference base circle radius of the scroll (constant);
• b is the constant (b > 0);
• a is the base circle radius of the scroll (variable with φ as a parameter);
• φ is the involute angle of the scroll (parameter variable);
• α is the wrap thickness angle of the scroll (constant, α < 0.5 π);
• t is the wrap thickness of the scroll (variable with φ as a parameter);
• R is the radius of the orbital path of the orbiting scroll, that is, the orbit in which the orbiting scroll orbits (variable with φ as a parameter);
• Rmin is the minor axis of the orbital path of the orbiting scroll (constant);
• Rmax is the major axis of the orbital path of the orbiting scroll (constant);
• W1 is the total mass of the orbiting scroll and the slider (constant); and
• W2 is the mass of the Oldham ring (constant).
• When Equation (16) is transformed, the following relationship is obtained. $$\mathrm{Rmin}:\mathrm{Rmax}=\mathrm{W}1:\left(\mathrm{<figure-callout\; id="1"\; label="W"\; filenames="imgf0003.png,imgf0007.png"\; state="\{\{state\}\}">W</figure-callout>}1+\mathrm{<figure-callout\; id="2"\; label="W"\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">W</figure-callout>}2\right)$$

  
• That is, in Embodiment 4, as in Embodiment 3, the ratio between the minor axis Rmin and the major axis Rmax is equal to the ratio between the total mass W1 of the orbiting scroll 2 and the slider 32 and the total mass (= W1 + W2) of the orbiting scroll 2, the slider 32, and the Oldham ring 6.
• The other configurations and operations of Embodiment 4 are the same as those of Embodiment 1 or Embodiment 2, and their descriptions will thus be omitted.
• Embodiment 4 differs from Embodiment 3 as follows. The base circle radius a of the scroll in Embodiment 3 is a constant, whereas the base circle radius a of the scroll in Embodiment 4 is a variable with the involute angle φ with a parameter. From comparison between Figs. 4 and 6, it can be seen that the overall outside shape of each of the fixed scroll 1 and the orbiting scroll 2 in Fig. 4 is a shape close to a circle, whereas the overall outside shape of each of the fixed scroll 1 and the orbiting scroll 2 in Fig. 6 is a shape close to an ellipse having a horizontal major axis. Furthermore, regarding the definitional equations of the minor axis Rmin 51 (see Fig. 2) and the major axis Rmax 52 (see Fig. 2) of the orbital path 50 of the orbiting scroll 2, in Equations (14) and (15), the definitional equations are different from those in Equations (6) and (7) described above, respectively.
• By virtue of such a configuration, it is possible to reduce an imbalance that is caused by the simple harmonic motion of the Oldham ring 6, whose effect varies depending on the vibration measurement phase, thus reducing vibration of the scroll compressor 100.
• Fig. 7 is a diagram indicating how the amount of imbalance of the scroll compressor 100 according to Embodiment 4 is reduced. In Fig. 7, the horizontal axis represents the vibration measurement phase θ, and the vertical axis represents the balance amount. In Fig. 7, a broken line Up represents a graph indicating the balance amount in the related art, for example, Patent Literature 1, and a solid line Ub represents a graph indicating the balance amount in Embodiment 4. As illustrated in Fig. 7, a peak value of the balance amount Ub in Embodiment 4 is approximately 1/4 of a peak value of the balance amount Up in the related art, and in Embodiment 4, it can be seen that the fluctuation of the balance amount which varies depending on the vibration measurement phase, that is, the amount of imbalance, is greatly reduced.
• As described above, in Embodiment 4, as in Embodiment 1, the orbital path 50 of the orbiting scroll 2 is elliptical, and the minor axis Rmin 51 of the orbital path 50 of the orbiting scroll 2 is made to coincide with the direction of the simple harmonic motion of the Oldham ring 6. Thus, the same advantages as in Embodiment 1 are obtained.
• In Embodiment 4, as in Embodiment 2, the sliding direction (direction indicated by the arrows B) of the slider 32 may be made to coincide with the direction of a centrifugal force on the orbiting scroll 2. In this case, in addition, the same advantages as in Embodiment 2 can also be obtained.
• Furthermore, the scroll compressor 100 according to Embodiment 4 has a configuration that satisfies Equations (9) to (16) described above. By virtue of such a configuration, in Embodiment 4, it is possible to greatly reduce an imbalance that is caused by the simple harmonic motion of the Oldham ring 6, whose effect varies depending on the vibration measurement phase, as compared with the related art, as illustrated in Fig. 7, thus greatly reducing vibration of the scroll compressor.
Embodiment 5
• Fig. 8 is a plan view illustrating the shape of the fixed scroll wrap 1a and the shape of the orbiting scroll wrap 2a of a scroll compressor 100 according to Embodiment 5.
• In Embodiment 5, the following limitations are added to the above configuration of Embodiment 1 or Embodiment 2. Specifically, each of the scroll wrap of the fixed scroll 1 and the scroll wrap of the orbiting scroll 2 has a shape expressed by Equations (17) and (18) described below. Each of the scrolls has a base circle radius a expressed by Equation (19) described below. The scroll has a wrap thickness angle α expressed by Equation (20) described below. The orbital path 50 of the orbiting scroll 2 has a radius R, a minor axis Rmin, and a major axis Rmax that are expressed by Equations (21), (22), and (23) described below, respectively. The scroll compressor 100 according to Embodiment 5 has a configuration in which the direction of the simple harmonic motion of an Oldham ring 6 is a direction along the Y-axis, and the minor axis Rmin, the major axis Rmax, and the constants (W1, W2) satisfy a relationship expressed by Equation (24) described below, where W1 is the total mass of the orbiting scroll 2 and a slider 32, and W2 is the mass of the Oldham ring 6, as in Embodiments 3 and 4. $$\mathrm{x}=\mathrm{a}\times \left\{\cos \mathrm{\varphi +}\left(\mathrm{\varphi }\pm \mathrm{\alpha }\right)\sin \mathrm{\varphi }\right\}$$

  

  $$\mathrm{y}=\mathrm{a}\times \left\{\sin \mathrm{\varphi +}\left(\mathrm{\varphi }\pm \mathrm{\alpha }\right)\cos \mathrm{\varphi }\right\}$$

  

  $$\mathrm{a}=\mathrm{a}1+\mathrm{b}\times {\mathrm{<figure-callout\; id="2"\; label="sin"\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">sin</figure-callout>}}^2\mathrm{\varphi }$$

  

  $$\mathrm{\alpha }=\mathrm{t}÷2\mathrm{a}$$

  

  $$\mathrm{R}=\mathrm{a}\mathrm{\pi }-\mathrm{t}$$

  

  $$\mathrm{Rmin}=\mathrm{a}1\times \mathrm{\pi }-\mathrm{t}$$

  

  $$\mathrm{Rmax}=\left(\mathrm{a}1+\mathrm{b}\right)\times \mathrm{\pi }-\mathrm{t}$$

  

  $$\mathrm{Rmax}\times \mathrm{<figure-callout\; id="1"\; label="W"\; filenames="imgf0003.png,imgf0007.png"\; state="\{\{state\}\}">W</figure-callout>}1=\mathrm{Rmin}\times \left(\mathrm{<figure-callout\; id="1"\; label="W"\; filenames="imgf0003.png,imgf0007.png"\; state="\{\{state\}\}">W</figure-callout>}1+\mathrm{<figure-callout\; id="2"\; label="W"\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">W</figure-callout>}2\right)$$

  
• Parameters in Equations (17) to (24) are defined as follows:
• a1 is the reference base circle radius of the scroll (constant);
• b is the constant (b > 0);
• a is the base circle radius of the scroll (variable with φ as a parameter);
• φ is the involute angle of the scroll (parameter variable);
• α is the wrap thickness angle of the scroll (variable with φ as a parameter, α < 0.5 π); t is wrap thickness of the scroll (constant);
• R is the radius of the orbital path of the orbiting scroll, that is, the orbit in which the orbiting scroll orbits (variable with φ as a parameter);
• Rmin is the minor axis of the orbital path of the orbiting scroll (constant);
• Rmax is the major axis of the orbital path of the orbiting scroll (constant);
• W1 is the total mass of the orbiting scroll and the slider (constant); and
• W2 is the mass of the Oldham ring (constant);
• When Equation (24) is transformed, the following relationship is obtained. $$\mathrm{Rmin}:\mathrm{Rmax}=\mathrm{W}1:\left(\mathrm{<figure-callout\; id="1"\; label="W"\; filenames="imgf0003.png,imgf0007.png"\; state="\{\{state\}\}">W</figure-callout>}1+\mathrm{<figure-callout\; id="2"\; label="W"\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">W</figure-callout>}2\right)$$

  
• That is, in Embodiment 5, as in Embodiments 3 and 4, the ratio between the minor axis Rmin and the major axis Rmax is equal to the ratio between the total mass W1 of the orbiting scroll 2 and the slider 32 and the total mass (= W1 + W2) of the orbiting scroll 2, the slider 32, and the Oldham ring 6.
• In Embodiment 5, the other configurations and operations in Embodiment 5 are the same as those in Embodiment 1 or Embodiment 2, and their descriptions will thus be omitted.
• Embodiment 5 differs from Embodiment 3 as follows. The base radius a of the scroll is a constant in Embodiment 3, whereas the base circle radius a of the scroll is a variable with the involute angle φ as a parameter in Embodiment 5. Thus, from comparison between Figs. 4 and 8, it can be seen that the overall outside shape of each of the fixed scroll 1 and the orbiting scroll 2 as illustrated in Fig. 4 is a shape close to a circle, whereas the overall outside shape of each of the fixed scroll 1 and the orbiting scroll 2 as illustrated in Fig. 8 is a shape close to an ellipse having a horizontal major axis. Furthermore, regarding the definitional equations of the radius R, the minor axis Rmin 51 (see Fig. 2), and the major axis Rmax 52 (see Fig. 2) of the orbital path 50 of the orbiting scroll 2, in Equations (21) to (23), the definitional equations are different from those in Equations (5) to (7) described above, respectively.
• In Embodiment 5, by virtue of the above configuration, it is possible to reduce an imbalance that is caused by the simple harmonic motion of the Oldham ring 6, whose effect varies depending on the vibration measurement phase, thus greatly reducing vibration of the scroll compressor 100.
• In addition, Embodiment 5 is different from Embodiments 3 and 4 as follows. In Embodiments 3 and 4, the wrap thickness t of each of the fixed scroll wrap 1a and the orbiting scroll wrap 2a is a variable with the involute angle φ as a parameter. In contrast, in Embodiment 5, the wrap thickness t is a constant. Since the wrap thickness t in Embodiment 5 is constant, the scroll is stable in strength in view of wrap thickness, and the reliability of the scroll is thus further improved, as compared with Embodiments 3 and 4.
• Fig. 9 is an explanatory view indicating how the imbalance of the scroll compressor 100 according to Embodiment 5 is reduced. In Fig. 9, the horizontal axis represents the vibration measurement phase θ, and the vertical axis represents the balance amount. In addition, In Fig. 9, a broken line Up represents a graph indicating the balance amount in the related art, for example, in Patent Literature 1, and a solid line Uc represents a graph indicating the balance amount in Embodiment 5. As illustrated in Fig. 9, a peak value of the balance amount Uc in Embodiment 5 is approximately 1/4 of a peak value of the balance amount Up in the related art. In Embodiment 5, the fluctuation of the balance amount, which varies depending on the vibration measurement phase, or the amount of imbalance, is greatly reduced.
• As described above, in Embodiment 5, as in Embodiment 1, the orbital path 50 of the orbiting scroll 2 is elliptical, and the minor axis Rmin 51 of the orbital path 50 of the orbiting scroll 2 is made to coincide with the direction of the simple harmonic motion of the Oldham ring 6. Thus, the same advantages as those in Embodiment 1 are obtained.
• In Embodiment 5, as in Embodiment 2, the sliding direction (direction of arrows B) of the slider 32 may be made to coincide with the direction of a centrifugal force on the orbiting scroll 2. In this case, the same advantages as those in Embodiment 2 can further be obtained.
• In addition, the scroll compressor 100 according to Embodiment 5 has a configuration that satisfies Equations (17) to (24) described above. By virtue of such a configuration, in Embodiment 5, it is possible to greatly reduce an imbalance that is caused by the simple harmonic motion of the Oldham ring 6, whose effect varies depending on the vibration measurement phase, as compared with the related art, as illustrated in Fig. 9, thus greatly reducing vibration of the scroll compressor.
• Unlike Embodiments 3 and 4, in Embodiment 5, the wrap thickness t is constant, and the scroll is thus stable in strength in view of wrap thickness and is further improved in reliability.
Reference Signs List
• 1: fixed scroll, 1a: fixed scroll wrap, 1b: fixed scroll bedplate, 1aa: inwardly facing surface, 1ab: outwardly facing surface, 2: orbiting scroll, 2a: orbiting scroll wrap, 2aa: inwardly facing surface, 2ab: outwardly facing surface, 2b: orbiting scroll bedplate, 2c: orbiting scroll thrust bearing surface, 2d: boss, 3: thrust plate, 4: Oldham key groove, 5: Oldham key groove, 6: Oldham ring, 6ab: Oldham key, 6ac: Oldham key, 6b: ring portion, 7: center shell, 8: main shaft, 8a: eccentric shaft portion, 9: power supply terminal, 10: stator, 11: rotor, 12: first balance weight, 13: second balance weight, 14: suction pipe, 15: discharge port, 16: discharge pipe, 17: low-pressure chamber, 18: high-pressure chamber, 19: frame, 19c: Oldham ring space, 20: main bearing, 21: upper shell, 22: lower shell, 23: hermetic container, 24: compression chamber, 25: seal, 26: seal, 27: discharge valve, 28: sub-frame, 29: sub-bearing, 30: oil pump, 31: oil supply hole, 32: slider, 32a: eccentric bearing portion, 40: compression mechanism unit, 41: rotary drive unit, 50: orbital path, 50P: orbital path, 51: minor axis (Rmin), 52: major axis (Rmax), 53: center, 60: involute, 62: base circle, 63: inwardly facing surface, 64: outwardly facing surface, 100: scroll compressor

Claims (6)

1. A scroll compressor comprising:

   a fixed scroll including a fixed scroll bedplate formed in the shape of a plate and a fixed scroll wrap formed in the shape of a wall body and protruding from a first surface of the fixed scroll bedplate;

   an orbiting scroll including an orbiting scroll bedplate formed in the shape of a plate and an orbiting scroll wrap formed in the shape of a wall body and protruding from a first surface of the orbiting scroll bedplate, the orbiting scroll being configured to compress fluid in a compression chamber that is defined by a combination of the fixed scroll wrap and the orbiting scroll wrap;

   a main shaft provided at a second surface of the orbiting scroll bedplate that is located opposite to the first surface of the orbiting scroll bedplate, the main shaft including an eccentric shaft portion that is located at a first end of the main shaft and to which the orbiting scroll is attached;

   a slider provided between the eccentric shaft portion of the main shaft and the orbiting scroll, the slider being included in a variable crank mechanism configured to adjust a radius of orbital motion of the orbiting scroll;

   a rotary drive unit configured to rotate the main shaft to cause the orbiting scroll to orbit;

   a frame fixed to the fixed scroll and supporting the fixed scroll and the orbiting scroll; and

   an Oldham ring provided between the frame and the orbiting scroll, and configured to prevent the orbiting scroll from rotating on an axis of the orbiting scroll and convert rotational motion of the main shaft into orbital motion of the orbiting scroll,
   wherein

   the fixed scroll wrap has a side portion that supports an orbiting-scroll centrifugal force that is a centrifugal force generated by the orbital motion of the orbiting scroll,

   the Oldham ring performs simple harmonic motion during the orbital motion of the orbiting scroll,

   the orbiting scroll orbits in an elliptical orbit having a minor axis and a major axis, and

   a direction along the minor axis of the orbit of the orbiting scroll coincides with a direction of the simple harmonic motion of the Oldham ring.
2. The scroll compressor of claim 1, wherein

   the slider is slidable relative to the eccentric shaft portion of the main shaft, and

   a direction of the orbiting-scroll centrifugal force generated by the orbital motion of the orbiting scroll coincides with a direction in which the slider is slid.
3. The scroll compressor of claim 1 or 2, wherein a ratio of the minor axis and the major axis of the orbit in which the orbiting scroll orbits is equal to a ratio between a total mass of the orbiting scroll and the slider and a total mass of the orbiting scroll, the slider, and the Oldham ring.
4. The scroll compressor of any one of claims 1 to 3, wherein

   each of the fixed scroll wrap and the orbiting scroll wrap has a shape expressed by Equations (1) and (2) in an XY coordinate system with an involute angle φ as a parameter,

   each of the fixed scroll wrap and the orbiting scroll wrap has a wrap thickness angle α expressed by Equation (3),

   each of the fixed scroll wrap and the orbiting scroll wrap has a wrap thickness t expressed by Equation (4),

   the orbit in which the orbiting scroll orbits has a radius R, the minor axis, and the major axis, which are expressed by Equations (5), (6), and (7), respectively, the minor axis and the major axis being denoted by Rmin and Rmax, respectively,

   a direction of the simple harmonic motion of the Oldham ring is a direction along a Y-axis, and

   the minor axis Rmin and the major axis Rmax of the orbit in which the orbiting scroll orbits, the total mass of the orbiting scroll and the slider, and the total mass of the orbiting scroll, the slider, and the Oldham ring satisfy a relationship expressed by Equation (8), the total mass of the orbiting scroll and the slider and the total mass of the orbiting scroll, the slider, and the Oldham ring being denoted by W1 and W1 + W2, respectively, $$\mathrm{x}=\mathrm{a}\times \left\{\cos \mathrm{\varphi }+\left(\mathrm{\varphi }\pm \mathrm{\alpha }\right)\sin \mathrm{\varphi }\right\}$$

   

   $$\mathrm{y}=\mathrm{a}\times \left\{\sin \mathrm{\varphi }-\left(\mathrm{\varphi }\pm \mathrm{\alpha }\right)\cos \mathrm{\varphi }\right\}$$

   

   $$\mathrm{\alpha }=\mathrm{\alpha }1+\mathrm{b}\times {\cos }^2\mathrm{\varphi }$$

   

   $$\mathrm{t}=2\mathrm{a\alpha }$$

   

   $$\mathrm{R}=\mathrm{a}\times \left(\mathrm{\pi }-2\mathrm{\alpha }\right)$$

   

   $$\mathrm{Rmin}=\mathrm{a}\times \left\{\mathrm{\pi }-2\left(\mathrm{\alpha }1+\mathrm{b}\right)\right\}$$

   

   $$\mathrm{Rmax}=\mathrm{a}\times \left(\mathrm{\pi }-2\mathrm{\alpha }1\right)$$

   

   $$\mathrm{Rmax}\times \mathrm{W}1=\mathrm{Rmin}\times \left(\mathrm{W}1+\mathrm{W}2\right)$$

   

   where

   a is a base circle radius of the scroll (constant),

   b is a constant (b > 0),

   α1 is a reference wrap thickness angle of the scroll (constant),

   φ is the involute angle of the scroll (parameter variable),

   π), α is the wrap thickness angle of the scroll (variable with φ as a parameter, α < 0.5

   t is the wrap thickness of the scroll (variable with φ as a parameter),

   R is the radius of the orbit in which the orbiting scroll orbits (variable with φ as a parameter),

   Rmin is the minor axis of the orbit in which the orbiting scroll orbits (constant),

   Rmax is the major axis of the orbit in which the orbiting scroll orbits (constant),

   W1 is the total mass of the orbiting scroll and the slider (constant), and

   W2 is a mass of the Oldham ring (constant).
5. The scroll compressor of any one of claims 1 to 3, wherein

   each of the fixed scroll wrap and the orbiting scroll wrap has a shape expressed by Equations (9) and (10) in an XY coordinate system with an involute angle φ as a parameter,

   each of the fixed scroll wrap and the orbiting scroll wrap has a base circle radius expressed by Equation (11),

   each of the fixed scroll wrap and the orbiting scroll wrap has a wrap thickness t expressed by Equation (12),

   the orbit in which the orbiting scroll orbits has a radius R, the minor axis, and the major axis, which are expressed by Equations (13), (14), and (15), respectively, the minor axis and the major axis being denoted by Rmin and Rmax, respectively

   a direction of the simple harmonic motion of the Oldham ring is a direction along a Y-axis, and

   the minor axis Rmin and the major axis Rmax of the orbit in which the orbiting scroll orbits, a total mass of the orbiting scroll and the slider, and a total mass W1 + W2 of the orbiting scroll, the slider, and the Oldham ring satisfy a relationship expressed by Equation (16), the total mass of the orbiting scroll and the slider and the total mass of the orbiting scroll, the slider, and the Oldham ring being denoted by W1 and W1 + W2, respectively, $$\mathrm{x}=\mathrm{a}\times \left\{\cos \mathrm{\varphi }+\left(\mathrm{\varphi }\pm \mathrm{\alpha }\right)\sin \mathrm{\varphi }\right\}$$

   

   $$\mathrm{y}=\mathrm{a}\times \left\{\sin \mathrm{\varphi }-\left(\mathrm{\varphi }\pm \mathrm{\alpha }\right)\cos \mathrm{\varphi }\right\}$$

   

   $$\mathrm{a}=\mathrm{a}1+\mathrm{b}\times {\sin }^2\mathrm{\varphi }$$

   

   $$\mathrm{t}=2\mathrm{a\alpha }$$

   

   $$\mathrm{R}=\mathrm{a}\times \left(\mathrm{\pi }-2\mathrm{\alpha }\right)$$

   

   $$\mathrm{Rmin}=\mathrm{a}1\times \left(\mathrm{\pi }-2\mathrm{\alpha }\right)$$

   

   $$\mathrm{Rmax}=\left(\mathrm{a}1+\mathrm{b}\right)\times \left(\mathrm{\pi }-2\mathrm{\alpha }\right)$$

   

   $$\mathrm{Rmax}\times \mathrm{W}1=\mathrm{Rmin}\times \left(\mathrm{W}1+\mathrm{W}2\right)$$

   

   where

   a1 is a reference base circle radius of the scroll (constant),

   b is a constant (b > 0),

   a is the base circle radius of the scroll (variable with φ as a parameter),

   φ is the involute angle of the scroll (parameter variable),

   α is a wrap thickness angle of the scroll (constant, α < 0.5 π),

   t is the wrap thickness of the scroll (variable with φ as a parameter),

   R is the radius of the orbit in which the orbiting scroll orbits (variable with φ as a parameter),

   Rmin is the minor axis of the orbit in which the orbiting scroll orbits (constant),

   Rmax is the major axis of the orbit in which the orbiting scroll orbits (constant),

   W1 is the total mass of the orbiting scroll and the slider (constant), and

   W2 is a mass of the Oldham ring (constant).
6. The scroll compressor of any one of claims 1 to 3, wherein

   each of the fixed scroll wrap and the orbiting scroll wrap has a shape expressed by Equations (17) and (18) in an XY coordinate system with an involute angle φ as a parameter,

   each of the fixed scroll wrap and the orbiting scroll wrap has a base circle radius a expressed by Equation (19),

   each of the fixed scroll wrap and the orbiting scroll wrap has a wrap thickness angle α expressed by Equation (20),

   the orbit in which the orbiting scroll orbits has a radius R, the minor axis, and the major axis, which are expressed by Equations (21), (22), and (23), respectively, the minor axis and the major axis being denoted by Rmin and Rmax, respectively,

   a direction of the simple harmonic motion of the Oldham ring is a direction along a Y-axis, and

   the minor axis Rmin and the major axis Rmax of the orbit in which the orbiting scroll orbits, a total mass W1 of the orbiting scroll and the slider, and a total mass W1 + W2 of the orbiting scroll, the slider, and the Oldham ring satisfy a relationship expressed by Equation (24), the total mass of the orbiting scroll and the slider and the total mass of the orbiting scroll, the slider, and the Oldham ring being denoted by W1 and W1 + W2, respectively, $$\mathrm{x}=\mathrm{a}\times \left\{\cos \mathrm{\varphi }+\left(\mathrm{\varphi }\pm \mathrm{\alpha }\right)\sin \mathrm{\varphi }\right\}$$

   

   $$\mathrm{y}=\mathrm{a}\times \left\{\sin \mathrm{\varphi }-\left(\mathrm{\varphi }\pm \mathrm{\alpha }\right)\cos \mathrm{\varphi }\right\}$$

   

   $$\mathrm{a}=\mathrm{a}1+\mathrm{b}\times {\sin }^2\mathrm{\varphi }$$

   

   $$\mathrm{\alpha }=\mathrm{t}÷2\mathrm{a}$$

   

   $$\mathrm{R}=\mathrm{a}\mathrm{\pi }-\mathrm{t}$$

   

   $$\mathrm{Rmin}=\mathrm{a}1\times \mathrm{\pi }-\mathrm{t}$$

   

   $$\mathrm{Rmax}=\left(\mathrm{a}1+\mathrm{b}\right)\times \mathrm{\pi }-\mathrm{t}$$

   

   $$\mathrm{Rmax}\times \mathrm{W}1=\mathrm{Rmin}\times \left(\mathrm{W}1+\mathrm{W}2\right)$$

   

   where

   a1 is a reference base circle radius of the scroll (constant),

   b is a constant (b > 0),

   a is the base circle radius of the scroll (variable with φ as a parameter),

   φ is the involute angle of the scroll (parameter variable),

   α is a wrap thickness angle of the scroll (variable with φ as a parameter, α < 0.5 π), t is the wrap thickness of the scroll (constant),

   R is the radius of the orbit in which the orbiting scroll orbits (variable with φ as a parameter),

   Rmin is the minor axis of the orbit in which the orbiting scroll orbits (constant),

   Rmax is the major axis of the orbit in which the orbiting scroll orbits (constant),

   W1 is the total mass of the orbiting scroll and the slider (constant), and

   W2 is a mass of the Oldham ring (constant).

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