Compressor and refrigeration cycle device

Abstract

A compressor capable of improving the reliability of a bearing portion and compressor efficiency is provided. [Solution] The compressor includes a compression mechanism that forms a compression chamber (S1), a shaft that transmits power to the compression mechanism, a bearing (5) that supports the shaft, a back pressure chamber (S2) that has an intermediate pressure between suction pressure and discharge pressure, mechanisms (21c, 22e) that connect the compression chamber (S1) and the back pressure chamber (S2) and adjust the intermediate pressure, and an oil supply source on which discharge pressure acts. The compressor also includes an oil supply passage (3d, 6, 5, 15) that returns oil from the oil supply source to the oil supply source via the shaft and bearing (5), an oil supply system (R1) that supplies oil from the oil supply passage (3d, 6, 5, 15) via a seal member (13) to the back pressure chamber (S2), an oil supply communication passage (16) that branches off at a portion (15a) downstream of the bearing (5) from the oil supply passage (3d, 6, 5, 15 and communicates with the back pressure chamber (S2), and a control valve (17) provided in the oil supply communication passage (16) that adjusts the amount of oil supplied via the oil supply communication passage (16).

Description

[Technical Field]

[0001] The present invention relates to a compressor and a refrigeration cycle device including the compressor. [Background technology]

[0002] Compressors such as scroll compressors supply oil to the compression chamber to improve sealing within the chamber.In recent years, there has been a demand for performance under low loads, and there is a need to improve compressor efficiency under low-speed, low-pressure ratio conditions.However, there is a concern that the oil supply to the compression chamber may be insufficient under these conditions.

[0003] Regarding the supply of oil to the compression chamber, Japanese Patent No. 3696683 (Patent Document 1) discloses a configuration in which a hole or groove is provided on the back surface of the end plate of the orbiting scroll to enable adjustment of the amount of oil supplied to the compression chamber. In the configuration of Patent Document 1, oil is supplied to the back pressure chamber via a seal ring that separates the high pressure chamber and the back pressure chamber. Furthermore, Japanese Patent Laid-Open Publication No. 2006-336543 (Patent Document 2) discloses a configuration in which a control valve that opens under low load is provided in the oil supply passage from the space above the orbiting bearing to the back pressure chamber.

[0004] The oil supply amount through the holes in the rear surface of the head plate increases as the compressor rotation speed increases. The oil supply through the grooves in the rear surface of the head plate is based on the differential pressure between the high-pressure chamber and the back-pressure chamber. Therefore, the oil supply amount increases as the differential pressure increases. Therefore, with the prior art of Patent Document 1, there is a concern that the oil supply amount may be insufficient during low-load operation, when the compressor rotation speed is low and the differential pressure between the high-pressure chamber and the back-pressure chamber is small. On the other hand, adjusting the oil supply amount during low-load operation significantly increases the oil supply amount during high-load operation, when the rotation speed and differential pressure are high. This raises concerns that excessive oil may be supplied to the compression chamber during high-load operation, reducing compressor efficiency and reducing the amount of oil supplied to the main bearings. With the prior art of Patent Document 2, there is a concern that the amount of oil supplied to the bearings may decrease when the control valve is open. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 3696683 specification [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-336543 Summary of the Invention [Problem to be solved by the invention]

[0006] The present disclosure has been made in consideration of the above points, and aims to provide a compressor and a refrigeration cycle device equipped with the compressor that can suppress a decrease in the amount of oil supplied to the bearing unit while supplying a sufficient amount of oil to the compression chamber even under low-speed, low-pressure ratio conditions, thereby improving the reliability of the bearing unit and compressor efficiency. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems, the present disclosure provides a compressor having the following features. The compressor includes a compression mechanism that forms a compression chamber, a shaft that transmits power to the compression mechanism, a bearing that supports the shaft, a back pressure chamber that has a pressure intermediate between suction pressure and discharge pressure, a mechanism that connects the compression chamber and the back pressure chamber and adjusts the intermediate pressure, and an oil supply source on which the discharge pressure acts. The compressor also includes an oil supply passage that returns oil from the oil supply source to the oil supply source via the shaft and the bearing, an oil supply system that supplies oil from the oil supply passage via a seal member to the back pressure chamber, an oil supply communication passage that branches off at a position downstream of the bearing from the oil supply passage and communicates with the back pressure chamber, and a control valve that is provided in the oil supply communication passage and adjusts the amount of oil supplied via the oil supply communication passage. [Effects of the Invention]

[0008] With the above configuration, it is possible to supply a sufficient amount of oil to the compression chamber even under low-speed, low-pressure ratio conditions while suppressing a decrease in the amount of oil supplied to the bearing, thereby improving the reliability of the bearing and the compressor efficiency. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a longitudinal cross-sectional view of a scroll compressor according to one or more embodiments of the present disclosure. [Figure 2] FIG. 2 is a cross-sectional view of a scroll compressor near a main bearing and an orbiting bearing in accordance with one or more embodiments of the present disclosure. [Figure 3] FIG. 2 illustrates a first oil supply line (R1) at the bottom of the orbiting scroll in a scroll compressor according to one or more embodiments of the present disclosure. [Figure 4] 2 illustrates the structure and operation of a control valve 17 in a scroll compressor according to one or more embodiments of the present disclosure. [Figure 5] 1 illustrates the structure of a valve body of a control valve in a scroll compressor according to one or more embodiments of the present disclosure. [Figure 6] 1 is a diagram illustrating an example of the configuration of an air conditioner as a refrigeration cycle apparatus including a compressor according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0010] One or more embodiments of the present disclosure will be described below with reference to the drawings, but the embodiments of the present disclosure are not limited to the specific embodiments described below. Note that the same reference numerals throughout the drawings indicate the same or corresponding parts.

[0011] The present disclosure relates to a compressor (100) and a refrigeration cycle apparatus (200) including the compressor (100). The compressor (100) according to an embodiment of the present disclosure includes a compression mechanism (2) forming a compression chamber (S1), a shaft (3) transmitting power to the compression mechanism (2), a bearing (5) supporting the shaft, a back pressure chamber (S2) having an intermediate pressure between a suction pressure and a discharge pressure, mechanisms (21c, 22e) connecting the compression chamber (S1) and the back pressure chamber (S2) and adjusting the intermediate pressure, and an oil supply source (9) on which the discharge pressure acts. The compressor (100) includes an oil supply passage (3d, 6, 7a, 5, 15) that runs from an oil supply source (9) through a shaft (3) and a bearing (5) and returns to the oil supply source (9), an oil supply system (R1) that supplies oil from the oil supply passage through a seal member (13) to a back pressure chamber (S2), an oil supply communication passage (16) that branches off at a portion (15a) downstream of the bearing (5) in the oil supply passage and communicates with the back pressure chamber (S2), and a control valve (17) that is provided in the oil supply communication passage (16) and adjusts the amount of oil supplied through the oil supply communication passage (16).

[0012] With the above-described configuration, the oil supplied through the oil supply communication passage (16) branches at the downstream portion (15a) of the bearing portion (5) and communicates with the back pressure chamber (S2), so that even if the control valve (17) opens and oil is supplied to the back pressure chamber (S2), the amount of oil supplied to the bearing portion (5) does not decrease, and the reliability of the bearing portion (5) is not impaired. Furthermore, the oil supplied to the back pressure chamber (S2) is provided with a first oil supply system (R1) that supplies oil to the back pressure chamber (S2) from the oil supply passages (3d, 6, 7a, 5, 15) via the seal member (13) and a second oil supply system (R2) that supplies oil to the back pressure chamber (S2) via the control valve (17), which makes it easier to control the amount of oil supplied to the back pressure chamber (S2). The oil supplied to the back pressure chamber (S2) is supplied to the compression chamber (S1) through the mechanism (21c, 22e) for adjusting the intermediate pressure, and seals the gap between the wraps in the compression chamber (S1), improving compressor efficiency. As a result, while sufficient oil is supplied to the compression chamber (S1) even under low-speed, low-pressure ratio conditions, it is possible to suppress a decrease in the amount of oil supplied to the bearing (5) due to the opening of the control valve (17) and a decrease in compressor efficiency due to excessive oil supply under high-speed, high-pressure ratio conditions, thereby improving the reliability of the bearing (5) and compressor efficiency.

[0013] In a specific embodiment, the bearing portion is the main bearing 5, the oil supply line R1 branches off from a portion of the oil supply passage upstream of the main bearing 5, and the downstream portion 15a from which the oil supply communication passage 16 branches off is downstream of the main bearing 5. In a more specific embodiment, the oil supply line R1 branches off from a portion of the oil supply passage upstream of the main bearing 5 downstream of the slewing bearing 6, and the downstream portion 15a from which the oil supply communication passage 16 branches off is downstream of both the main bearing 5 and the slewing bearing 6.

[0014] In a preferred embodiment, the control valve (17) is configured to open in response to the pressure difference between the discharge pressure and the intermediate pressure becoming equal to or less than a threshold value. As a result, under high-load operation conditions where the pressure difference is large, oil is supplied via the first oil supply system (R1), while the control valve (17) is closed, and the amount of oil supplied via the second oil supply system (R2) is reduced. Then, under low-load operation conditions where the pressure difference is small, the amount of oil supplied via the control valve (17) is increased to compensate for the oil supplied via the first oil supply system (R1). As a result, a decrease in compressor efficiency can be prevented over a wide load range from high load to low load.

[0015] In a specific embodiment, the oil supply system (R1) supplies oil in accordance with the pressure difference between the discharge pressure and the intermediate pressure or the compressor rotation speed.

[0016] In a specific embodiment, the control valve (17) includes a valve element (17a), a valve seat (17c), and an elastic body (17e) that biases the valve element (17a) so that the valve element (17a) is pulled away from the valve seat (17c) and opens when the pressure difference between the discharge pressure and the intermediate pressure is small, and the valve element (17a) is brought into close contact with the valve seat (17c) and closes when the pressure difference is large.

[0017] In a specific embodiment, the compression mechanism (2) includes a fixed scroll (21) having a base plate (21a) and a spiral wrap (21b) extending from the base plate (21a), and an orbiting scroll (22) having an end plate (22a) and a spiral wrap (22b) extending from the end plate (22a), meshing with the fixed scroll (21) to form a compression chamber (S1), and receiving power from the shaft (3) to perform an orbiting motion. The compressor (100) further includes a frame (7) fastened to the fixed scroll (21) and positioned to sandwich the orbiting scroll (22) between the fixed scroll (21) and the frame (7), and pressure adjustment mechanisms (22e, 21c) connected to the compression chamber (S1) and a back pressure chamber (S2) to control the pressure of the back pressure chamber (S2). The back pressure chamber (S2) is formed by the fixed scroll (21), the orbiting scroll (22), and the frame (7), and is positioned behind the orbiting scroll (22).

[0018] In a specific embodiment, the pressure adjustment mechanism includes a back pressure communication passage (22e) connecting a back pressure chamber (S2) provided in the orbiting scroll (22) with the compression chamber (S1), and a back pressure groove (21c) provided in the fixed scroll (21). The oil supply passage includes an oil supply through hole (3d) passing through the inside of the shaft (3) for supplying oil from the oil supply source (9) to the bearing portion. Oil supplied to the back pressure chamber (S2) is guided to the compression chamber (S1) through the back pressure communication passage (22e) and seals the gap between the wraps (21b, 22b) of the orbiting scroll (22) and the fixed scroll (21). The compressor (100) is a scroll compressor.

[0019] In a specific embodiment, a refrigeration cycle apparatus (200) including the compressor (100) having the above-described configuration is further provided.

[0020] A compressor according to one or embodiments of the present disclosure will be described in more detail below with reference to Figures 1 to 5. A scroll compressor 100 will be described below as an example of a compressor according to a preferred embodiment, but the present disclosure is not necessarily limited to this.

[0021] FIG. 1 is a longitudinal cross-sectional view of a scroll compressor 100 according to one or more embodiments of the present disclosure. The scroll compressor 100 is a device that compresses a gaseous refrigerant. As shown in FIG. 1, the scroll compressor 100 includes a sealed container 1, a compression mechanism 2, a crankshaft 3, an electric motor 4, a main bearing 5, an orbiting bearing 6, a frame 7, and an Oldham ring 10. In addition to the components described above, the scroll compressor 100 also includes a subframe 11 and legs 12.

[0022] The sealed container 1 is a shell-shaped container that houses the compression mechanism 2, crankshaft 3, electric motor 4, frame 7, etc., and is substantially sealed. Lubricating oil for lubricating the compression mechanism 2 and the bearings (5, 6, 11a) is sealed in the sealed container 1, and is stored as an oil reservoir 9 at the bottom of the sealed container 1. The oil reservoir 9 corresponds to an oil supply source on which discharge pressure acts. The sealed container 1 includes a cylindrical chamber 1a, a lid chamber 1b that closes the upper side of the cylindrical chamber 1a, and a bottom chamber 1c that closes the lower side of the cylindrical chamber 1a.

[0023] A suction pipe P1 is inserted into and fixed to the cover chamber 1b of the sealed container 1. The suction pipe P1 is a pipe that guides the refrigerant to the suction port of the compression mechanism 2. Furthermore, a discharge pipe P2 is inserted into and fixed to the cylindrical chamber 1a of the sealed container 1. The discharge pipe P2 is a pipe that guides the refrigerant compressed by the compression mechanism 2 to the outside of the scroll compressor 100.

[0024] The electric motor 4 is a drive source that rotates the crankshaft 3 and is installed between the frame 7 and the subframe 11. As shown in FIG. 1, the electric motor 4 includes a stator 4a and a rotor 4b. The stator 4a is fixed to the inner peripheral wall of the cylindrical chamber 1a. The rotor 4b is rotatably disposed radially inside the stator 4a. The crankshaft 3 is fixed to the rotor 4b so as to be coaxial with its central axis.

[0025] The compression mechanism 2 is a mechanism that compresses a gaseous refrigerant as the crankshaft 3 rotates. The compression mechanism 2 includes a fixed scroll 21 and an orbiting scroll 22, and is disposed in an upper space within the sealed container 1.

[0026] The fixed scroll 21 is a member that forms a compression chamber (or suction chamber) S1 together with the orbiting scroll 22. The fixed scroll 21 is installed on the upper side of the frame 7 and is fixed to the frame 7 with bolts or the like. The frame 7 is a member that supports the fixed scroll 21. The frame 7 has a roughly rotationally symmetrical shape and is fixed to the inner peripheral wall of the cylindrical chamber 1a. The frame 7 is provided with an insertion hole through which the crankshaft 3 is inserted, and a main bearing 5 is provided in this insertion hole.

[0027] As shown in FIG. 1, the fixed scroll 21 includes a base plate 21a and a spiral-shaped fixed wrap 21b erected on the base plate 21a. The base plate 21a is a thick member having a circular shape in a plan view. The base plate 21a is provided with a suction port through which refrigerant is introduced via a suction pipe P1. The fixed wrap 21b is spiral-shaped and extends downward from the base plate 21a. The lower surface of the base plate 21a and the tooth tips of the fixed wrap 21b are substantially flush with each other. The lower surface of the base plate 21a is also referred to as the end plate surface 21f of the fixed scroll 21. The end plate surface 21f is provided with a circumferential groove through which lubricating oil is supplied.

[0028] The orbiting scroll 22 receives power from the crankshaft 3 and orbits to form a compression chamber (or suction chamber) S1 between itself and the meshed fixed scroll 21. The orbiting scroll 22 is provided between the fixed scroll 21 and the frame 7. As shown in FIG. 1, the orbiting scroll 22 includes an end plate 22a, a spiral orbiting wrap 22b erected on the end plate 22a, and a boss portion 22c. The end plate 22a is a portion that slides between itself and the end plate surface 21f of the fixed scroll 21 and is disk-shaped. The orbiting wrap 22b is a member that forms the compression chamber (or suction chamber) S1 together with the fixed wrap 21b and is spiral-shaped. The boss portion 22c is a portion that fits into the eccentric portion 3b of the crankshaft 3 and is cylindrical, as will be described later. As shown in FIG. 1, the orbiting wrap 22b extends upward from the end plate 22a. On the other hand, the boss portion 22c extends downward from the end plate 22a.

[0029] The spiral fixed wrap 21b and the spiral orbiting wrap 22b mesh together to form a compression chamber (or suction chamber) S1 between the fixed wrap 21b and the orbiting wrap 22b. The compression chambers (or suction chambers) S1 are spaces for compressing gaseous refrigerant and are formed on the outer and inner line sides of the orbiting wrap 22b. A discharge port J2 is provided near the center of the base plate 21a of the fixed scroll 21. The discharge port J2 is an opening that guides the refrigerant compressed in the compression chamber into a space S3 above the compression mechanism 2.

[0030] The crankshaft 3 shown in FIG. 1 is a shaft that rotates integrally with the rotor 4b of the electric motor 4 and extends in the vertical direction. As shown in FIG. 1, the crankshaft 3 includes a main shaft portion 3a and an eccentric portion 3b that extends upward from the main shaft portion 3a. The main shaft portion 3a is fixed coaxially to the rotor 4b of the electric motor 4 and rotates integrally with the rotor 4b. The eccentric portion 3b rotates eccentrically relative to the main shaft portion 3a, and as described above, is fitted into the boss portion 22c of the orbiting scroll 22. The eccentric rotation of the eccentric portion 3b causes the orbiting scroll 22 to orbit.

[0031] A main bearing 5 is provided in an insertion hole in the frame 7 through which the main shaft portion 3a of the crankshaft 3 is inserted. An orbiting bearing 6 is provided in a boss portion 22c of the orbiting scroll 22 through which the eccentric portion 3b of the crankshaft 3 is inserted. The main bearing 5 rotatably supports an upper portion of the main shaft portion 3a of the crankshaft 3 relative to the frame 7, and is installed on the peripheral wall surface of the insertion hole in the frame 7. The orbiting bearing 6 rotatably supports the eccentric portion 3b of the crankshaft 3 relative to the boss portion 22c of the orbiting scroll 22, and is installed on the inner peripheral surface of the boss portion 22c. In the embodiment described below, a rolling bearing is used for the main bearing 5, and a plain bearing is used for the orbiting bearing 6, but this is not particularly limited.

[0032] The Oldham ring 10 is a ring-shaped member that receives the eccentric rotation of the eccentric portion 3b and orbits the orbiting scroll 22 without rotating on its axis. The Oldham ring 10 is attached to a groove on the underside of the orbiting scroll 22 and is also attached to a groove in the frame 7.

[0033] A back pressure chamber S2 is provided on the counter-vortex side of the orbiting scroll 22. For example, when the gaseous refrigerant is compressed as the volume of the compression chamber S1 decreases, a downward force is generated that tries to pull the orbiting scroll 22 away from the fixed scroll 21. Therefore, the pressure in the back pressure chamber S2 pushes the orbiting scroll 22 toward the fixed scroll 21. The pressure in the back pressure chamber S2 is usually a predetermined intermediate pressure between the suction pressure and the discharge pressure of the scroll compressor 100. Note that the term "back pressure" in the back pressure chamber S2 does not particularly limit the pressure level of the back pressure chamber S2. The pressure in the back pressure chamber S2 is often a value between the suction pressure and the discharge pressure, but in some cases, it may temporarily become approximately equal to the discharge pressure. Note that the space in which the crankshaft 3, the orbiting bearing 6, and the main bearing 5 are provided is a high-pressure space approximately equal to the discharge pressure.

[0034] In the embodiment to be described, a pump 14 is provided at the bottom of the crankshaft 3, and lubricating oil is supplied from the oil reservoir 9 through an oil feed through hole 3d that penetrates the inside of the crankshaft 3. Note that, depending on the configuration, an oil feed piece (centrifugal pump) may be provided at the bottom of the crankshaft 3, and a configuration may be adopted in which the lubricating oil is sucked up from the oil reservoir 9 through the oil feed through hole 3d by differential pressure.

[0035] 1, the crankshaft 3 has an oil feed through hole 3d through which lubricating oil flows. The oil feed through hole 3d opens at the top of the crankshaft 3, and the lubricating oil is supplied from there to the slewing bearing 6 and then to the main bearing 5.

[0036] The subframe 11 is a member that rotatably supports the lower part of the main shaft portion 3a. As shown in FIG. 1, the subframe 11 is fixed to the sealed container 1 while being disposed below the electric motor 4. The subframe 11 is provided with a hole through which the crankshaft 3 is inserted. An auxiliary bearing 11a is installed on the peripheral wall surface of the hole of the subframe 11. The auxiliary bearing 11a rotatably supports the lower part of the main shaft portion 3a relative to the subframe 11. A plurality of legs 12 support the sealed container 1 and are installed on the bottom chamber 1c.

[0037] When the crankshaft 3 is rotated by the drive of the electric motor 4, the orbiting scroll 22 orbits accordingly. As a result, the compression chambers S1 formed one after another shrink, and the gaseous refrigerant is compressed. The compressed refrigerant is discharged into the upper space S3 of the compression mechanism 2 through the discharge port J2 of the fixed scroll 21. The refrigerant discharged into the upper space S3 in this manner is guided to the motor chamber S4 through a flow path between the compression mechanism 2 and the sealed container 1, and further discharged to the outside through the discharge pipe P2.

[0038] Furthermore, the lubricating oil stored as an oil sump at the bottom of the sealed container 1 rises from the lower part of the crankshaft 3 through the oil feed through hole 3d, is supplied to the sub-bearing 11a and the orbiting bearing 6, and is further supplied to the main bearing 5, lubricating these. The lubricating oil that reaches the opening at the upper end of the oil feed through hole 3d is led to the oil feed passage of the orbiting scroll 22.

[0039] The oil supply path in the scroll compressor 100 according to one or more embodiments of the present disclosure will be described in more detail below with reference to Figure 2. The orbiting scroll 22 is provided with a backpressure communication passage 22e that connects the backpressure chamber S2 and the compression chamber S1. The fixed scroll 21 is provided with a backpressure groove 21c. As described above, the backpressure chamber S2 between the orbiting scroll 22 and the frame 7 is at an intermediate pressure, but the pressure in the backpressure chamber S2 is adjusted by the backpressure communication passage 22e provided in the orbiting scroll 22 and the backpressure groove 21c provided in the fixed scroll 21.

[0040] Discharge pressure acts on the orbiting bearing 6 of the orbiting scroll 22, and the space of the discharge pressure and the back pressure chamber S2 are separated by the seal ring 13. The orbiting scroll 22 is pressed against and held in place by the intermediate pressure (back pressure) between the discharge pressure of the orbiting bearing 6 and the back pressure chamber S2.

[0041] The frame 7 is provided with a main bearing 5, and the crankshaft 3 is held by the main bearing 5. The crankshaft 3 is rotated by the electric motor 4, and transmits power to the orbiting scroll 22 via the orbiting bearing 6 of the orbiting scroll.

[0042] Oil in an oil sump 9 located at the bottom of the compressor, which is at discharge pressure, is pumped up by a pump 14 and supplied to the orbiting bearing 6 via an oil feed through hole 3d inside the crankshaft 3. A portion of the oil that has fed the orbiting bearing 6 is supplied to the back pressure chamber S2 via a seal ring 13 through a hole 22f or groove 22d provided at the bottom of the orbiting scroll 22, and the remainder is supplied to the main bearing 5 through a main bearing oil feed hole 7a provided in the frame 7. The oil supplied to the back pressure chamber S2 is guided to the compression chamber S1 through a back pressure communication passage 22e in the orbiting scroll 22, which adjusts the back pressure. The oil supplied to the compression chamber S1 seals the gap between the orbiting wrap 22b of the orbiting scroll 22 and the fixed wrap 21b of the fixed scroll 21, reducing refrigerant leakage and improving compressor efficiency. On the other hand, the amount of oil supplied to the compression chamber S1 is appropriate because the heating of the refrigerant caused by the high-temperature oil flowing into the compression chamber S1 increases the pressure in the compression chamber S1 and reduces the compressor efficiency.

[0043] 1 and 2, there is a concern that the amount of oil supplied to the compression chamber S1 may be insufficient under conditions of low speed and low pressure ratio. In response to this, even if an attempt is made to adjust the amount of oil supplied to increase the amount of oil supplied during low load operation, there is a concern that the amount of oil supplied may exceed the appropriate amount during high load operation with high rotation speed and high differential pressure, resulting in a decrease in compressor efficiency due to an excessive amount of oil supplied.

[0044] Therefore, in one or more embodiments of the present disclosure, in addition to a first oil supply system (R1) that supplies oil to the back pressure chamber S2 via a seal ring 13 from an oil supply passage (3d, 6, 7a, 5, 15) that returns from the oil sump 9 via the crankshaft 3, the slewing bearing 6, and the main bearing 5, a configuration is adopted that includes a second oil supply system (R2) via an oil supply communication passage 16 that includes a control valve 17. Oil supply by the first oil supply system (R1) is adjusted to accommodate high-load operation that results in high rotation speeds and high differential pressures, while the control valve 17 is opened during low-load operation to compensate for a shortage of oil supply by the first oil supply system (R1) during low-load operation, and the control valve 17 is adjusted to increase the amount of oil supplied by the second oil supply system (R2). In this case, as the amount of oil supplied to the second oil supply system (R2) increases, there may be a concern that the amount of oil supplied to the main bearing 5 will decrease. However, by configuring the oil supply communication passage 16 so that it branches off at a portion 15a downstream of the main bearing 5 in the oil supply passage and communicates with the back pressure chamber S2, this concern about a decrease in the amount of oil supplied to the main bearing 5 can be addressed.

[0045] The oil supply path according to the embodiment of the present disclosure will be described in more detail below. In the embodiment described, a portion of the oil that has supplied oil to the main bearing 5 passes through an oil supply communication passage 16 equipped with a control valve 17 and is supplied to the back pressure chamber S2. The remaining oil then returns to the oil sump 9 at the bottom of the compressor via an oil drain pipe 15.

[0046] As will be described later with reference to Fig. 4, control valve 17 includes a valve element 17a, a valve seat 17c, and a spring 17e, and the opening degree of control valve 17 is controlled by the balance between the force due to the differential pressure between the discharge pressure and the intermediate pressure (back pressure) acting on valve element 17a and the force of spring 17e, and control valve 17 opens and closes depending on the operating conditions. The structure and operation of control valve 17 will be described in more detail with reference to Fig. 4.

[0047] Oil supply communication passage 16 is provided at a position downstream of main bearing 5, and supplies oil to back pressure chamber S2 after lubricating main bearing 5, so even if control valve 17 opens and oil is supplied to back pressure chamber S2, the amount of oil supplied to main bearing 5 does not decrease, and the reliability of main bearing 5 is not reduced. Furthermore, when control valve 17 opens, there is no need to increase the amount of oil supplied by the pump from oil sump 9 to ensure the reliability of main bearing 5, so the amount of oil circulating inside scroll compressor 100 can be reduced, and the amount of oil discharged outside the compressor together with the refrigerant can also be reduced.

[0048] FIG. 3 is a diagram illustrating the first oil supply system (R1) at the bottom of the orbiting scroll 22. FIG. 3 is a diagram illustrating the orbiting scroll 22 as viewed from the bottom. FIGS. 3(A) and 3(B) illustrate different rotation phases of the crankshaft 3. As shown in FIG. 3, a groove (also referred to as a slit) 22d and a hole (also referred to as a pocket) 22f are provided at the bottom of the orbiting scroll 22. Lubricating oil is supplied from the discharge pressure space to the intermediate pressure space (back pressure chamber S2) through the groove 22d and / or the hole 22f. In FIGS. 3(A) and 3(B), the position of the seal ring 13 is indicated by a dashed line 13a. The gray area inside the seal ring 13 is the discharge pressure space, and the area outside of that is the intermediate pressure (back pressure) space. The lubricating oil is supplied from the discharge pressure side to the intermediate pressure side, and Fig. 3(A) shows a state in which the groove 22d connects the discharge pressure space and the intermediate pressure space, allowing the lubricating oil to flow. Fig. 3(B) shows a state in which the groove 22d is contained within the discharge pressure space, preventing the lubricating oil from flowing.

[0049] The amount of oil supplied through the hole 22f at the bottom of the orbiting scroll 22 increases as the compressor rotation speed increases. Oil supply through the groove 22d at the bottom of the orbiting scroll 22 is based on the differential pressure between the discharge pressure and the back pressure chamber. Therefore, the amount of oil supplied through the hole 22f, the groove 22d, or both at the bottom of the orbiting scroll 22 increases as the differential pressure increases. Therefore, oil supply through the hole 22f, the groove 22d, or both at the bottom of the orbiting scroll 22 decreases during low-load operation when the compressor rotation speed is low and the differential pressure between the discharge pressure and the back pressure is small. However, oil supply through the oil supply passage 16 equipped with the control valve 17 increases only under specific operating conditions, depending on the differential pressure between the discharge pressure and the intermediate pressure. More specifically, when the differential pressure between the discharge pressure and the intermediate pressure is within a certain threshold, i.e., when the differential pressure between the discharge pressure and the intermediate pressure is within a predetermined small range, the control valve 17 opens and oil supply is performed.

[0050] By adopting the above-described configuration, the oil supplied to the back pressure chamber S2 has at least two systems, including a first oil supply system (R1) supplied through the holes 22f or grooves 22d provided in the orbiting scroll 22 and a second oil supply system (R2) supplied through the control valve 17, making it easier to control the amount of oil supplied to the back pressure chamber S2. By controlling the amount of oil supplied to the back pressure chamber S2, which varies depending on the operating conditions, the amount of oil supplied to the compression chamber S1 can be controlled, and compressor efficiency can be improved.

[0051] The structure and operation of control valve 17 will be described in more detail below with reference to Figures 4 and 5. Figure 4(A) shows control valve 17 in a closed state, and Figure 4(B) shows control valve 17 in an open state. Figure 5 is a diagram illustrating the structure of valve element 17a of control valve 17 in more detail.

[0052] As shown in FIG. 4, the control valve 17 includes a valve element 17a, a valve seat 17c, and a spring 17e. The control valve 17 shown in FIG. 4 is a so-called poppet valve, although not limited thereto. The valve seat 17c accommodates a coil spring 17e and is provided with a spring receiving / flow path hole 17d that forms a flow path through which oil passes. The valve element 17a is disc-shaped as shown in FIG. 5 and is connected to the spring 17e at its center as indicated by the thick circle in FIG. 5. The valve element 17a has openings 17b arranged in a circle around its center. When the valve element 17a is separated from the seal surface S of the valve seat 17c, oil flows in through the opening 17b, passes through the spring receiving / flow path hole 17d, and is supplied to the back pressure chamber S2. On the other hand, when the valve body 17a is pressed against the seal surface S of the valve seat 17c, the opening 17b is closed by the valve seat 17c, and oil is not supplied.

[0053] 4, control valve 17 closes (FIG. 4(A)) when the force due to the pressure difference between the discharge pressure and the intermediate pressure acting on both sides of valve body 17a becomes larger than the force determined by the spring constant of spring 17e, and opens (FIG. 4(B)) when the force due to the pressure difference becomes smaller than the force of spring 17e. As a result, oil is supplied to back pressure chamber S2 through oil supply passage 16 only during low load operation when the pressure difference between the discharge pressure and the intermediate pressure is small.

[0054] The amount of oil supplied to the back pressure chamber S2 through the first oil supply path via the hole 22f or groove 22d provided in the orbiting scroll 22 tends to be small during low load operation and large during high load operation. On the other hand, the amount of oil supplied through the second oil supply path via the control valve 17 compensates for the shortage of oil supplied through the first oil supply path during low load operation by opening the control valve 17, thereby improving the sealing of the compression chamber and improving compressor efficiency.

[0055] In the embodiment described below, the control valve 17 is described as a poppet valve by way of example, but the specific structure of the control valve 17 is not necessarily limited to a poppet valve, and in other embodiments, the control valve 17 may have other valve structures such as a reed valve. The specific structure of the control valve 17 is configured so that an elastic body keeps the valve body closed, and the valve opens when pressure exceeds a certain level, so that it can be used as a so-called check valve.

[0056] Hereinafter, with reference to Fig. 6, a refrigeration cycle apparatus including a scroll compressor 100 according to an embodiment of the present disclosure will be described using an air conditioner 200 as an example. Fig. 6 is a diagram showing an example configuration of an air conditioner 200 as a refrigeration cycle apparatus including a compressor according to an embodiment of the present disclosure. The air conditioner 200 is configured to include an outdoor unit 109 installed outdoors, such as a house or building, and multiple indoor units 110 installed indoors. The outdoor unit 109 and each indoor unit 110 are connected by two connection pipes 115, 116 through which a refrigerant circulates as a heat medium.

[0057] The refrigerant used may be a hydrofluorocarbon such as R410A or R32. During operation, the indoor unit 110 takes in indoor air, exchanges heat between the taken-in air and the refrigerant supplied from the outdoor unit 109, and blows out cooled or heated air to cool or heat the room to a set temperature. To this end, the indoor unit 110 is equipped with an indoor heat exchanger 111 that exchanges heat between the indoor air and the refrigerant, and a blower (fan) 113 that takes in indoor air into the indoor heat exchanger 111 and blows out the air that has undergone heat exchange by the indoor heat exchanger 111. The indoor unit 110 also includes an indoor expansion valve 112 that expands the refrigerant and adjusts the flow rate of the refrigerant flowing through the indoor heat exchanger 111. The indoor unit 110 is equipped with a temperature sensor 114.

[0058] When operating in the cooling cycle, the indoor heat exchanger 111 functions as an evaporator, and refrigerant in a two-phase flow state, a mixture of liquid and gas, flows into the indoor heat exchanger 111. The liquid component of the refrigerant evaporates as it exchanges heat with air taken in by the fan 113 in the indoor heat exchanger 111, and the refrigerant is discharged from the indoor heat exchanger 111 as gas refrigerant and sent to the outdoor unit 109. The liquid component evaporates at a certain temperature (saturation temperature) that corresponds to the pressure inside the indoor heat exchanger 111, and is discharged from the indoor heat exchanger 111 at the saturation temperature or a temperature higher than the saturation temperature. The flow of refrigerant in the cooling cycle is indicated by solid arrows.

[0059] In the heating cycle, the indoor heat exchanger 111 functions as a condenser, and refrigerant gas flows into the indoor heat exchanger 111 from the outdoor unit 109. The refrigerant exchanges heat with air taken in by the fan 113 inside the indoor heat exchanger 111, becomes liquid refrigerant, and is sent to the outdoor unit 109. Note that the flow of refrigerant in the heating cycle is opposite to the flow in the cooling cycle, as indicated by the solid arrows.

[0060] The outdoor unit 109 starts up upon receiving instructions from a control device (not shown) and begins operation in an operation mode set by a remote controller or the like. The operation modes include cooling mode, heating mode, fan mode, etc. The outdoor unit 109 stops operation upon receiving a command from the remote controller or the like.

[0061] The outdoor unit 109 is connected to a plurality of indoor units 110a to 110c and circulates a refrigerant. The outdoor unit 109 is equipped with a scroll compressor 100 to circulate the refrigerant. In the cooling cycle, the refrigerant gas compressed by the scroll compressor 100 exchanges heat with air taken in by the fan 105 in the outdoor heat exchanger 103 and becomes a liquid refrigerant. The liquid refrigerant is sent to the indoor unit 110. The gas refrigerant from the indoor unit 110 flows into the outdoor unit 109 and is returned to the scroll compressor 100.

[0062] The outdoor unit 109 is also equipped with a four-way valve 102 for reversing the direction of refrigerant flow to enable heating operation. In the heating cycle, the four-way valve 102 has a different path from that shown in FIG. 6, and the refrigerant gas compressed by the scroll compressor 100 is sent to the indoor unit 110. Liquid refrigerant from the indoor unit 110 flows into the outdoor unit 109, evaporates through heat exchange with air taken in by the fan 105 in the outdoor heat exchanger 103, is discharged as gas refrigerant from the indoor heat exchanger 111, and is returned to the scroll compressor 100. The outdoor expansion valve 104 is provided to convert the high-pressure refrigerant into a low-temperature, low-pressure refrigerant in the heating cycle and to adjust the flow rate of the refrigerant.

[0063] 6, the outdoor unit 109 may further include a subcooling mainstream pipe 106a and a subcooling heat exchanger 107 that subcools the refrigerant passing through the subcooling mainstream pipe 106a. The outdoor unit 109 is provided with a subcooling expansion valve 108, and some of the refrigerant passes through a subcooling side flow pipe 106b, is decompressed by the subcooling expansion valve 108, and enters the subcooling heat exchanger 107, where it exchanges heat with the refrigerant from the subcooling mainstream pipe 106a and evaporates, and is then returned to the scroll compressor 100.

[0064] The scroll compressor 100 according to the embodiment of the present disclosure can be suitably applied to a refrigeration cycle device such as an air conditioner 200.

[0065] In the above-described embodiment, the air conditioner 200 has been described as an example of a refrigeration cycle apparatus according to an embodiment of the present disclosure. However, the refrigeration cycle apparatus is not limited to an air conditioner and may include what is also called a refrigeration air conditioning apparatus. Here, the term refrigeration air conditioning apparatus collectively refers to devices that use a refrigerant and a refrigeration cycle, such as the air conditioner described above, as well as freezers and refrigerators. More specifically, examples of refrigeration air conditioning apparatus include the above-described air conditioners such as package air conditioners and multi-air conditioners for buildings, heat source equipment such as freezers and chilling units, commercial freezers such as showcases, refrigerator-freezers, unit coolers, and ice makers, transportation refrigeration equipment such as car air conditioners, and heat pump water heaters.

[0066] According to the embodiment described above, sufficient oil can be supplied to the compression chamber S1 even under low-speed, low-pressure ratio conditions. At the same time, it is possible to provide a compressor and a refrigeration cycle apparatus including the compressor that can suppress a decrease in the amount of oil supplied to the main bearing 5 and improve the reliability of the main bearing 5 and compressor efficiency.

[0067] More specifically, the oil supplied through the oil supply communication passage 16 branches at a portion 15a downstream of the main bearing 5 and communicates with the back pressure chamber S2. Therefore, even when the control valve 17 opens and oil is supplied to the back pressure chamber S2, the amount of oil supplied to the bearing portion (more specifically, the main bearing 5) does not decrease, and the reliability of the main bearing 5 is not impaired. Furthermore, the oil supplied to the back pressure chamber S2 is provided through a first oil supply system R1 that supplies oil to the back pressure chamber S2 from the oil supply passage via the seal ring 13, and a second oil supply system R2 that supplies oil to the back pressure chamber S2 via the control valve 17, making it easier to control the amount of oil supplied to the back pressure chamber S2. Consequently, even under low-speed, low-pressure ratio conditions, sufficient oil is supplied to the compression chamber S1, while suppressing a decrease in compressor efficiency due to oversupply and a decrease in the amount of oil supplied to the main bearing 5 due to the opening of the control valve 17. This makes it possible to improve the reliability of the main bearing 5 and the compressor efficiency.

[0068] It should be noted that the embodiments of the present invention are not limited to the above-described embodiments and may include various modifications. For example, the above-described embodiments have been described in detail for ease of understanding, and are not necessarily limited to those including all of the described features. Furthermore, some of the features of one embodiment may be replaced with features of another embodiment, or features of one embodiment may be added to features of another embodiment. Furthermore, some of the features of each embodiment may be added to, deleted from, or replaced with other features. [Explanation of symbols]

[0069] 100...Scroll compressor, 1...Sealed vessel, 2...Compression mechanism, 21...Fixed scroll, 21a...Base plate, 21b...Fixed wrap, 21c...Back pressure groove, 22...Orbiting scroll, 22a...End plate, 22b...Orbiting wrap, 22c...Boss portion, 22d...Groove, 22e...Back pressure communication passage, 22f...Hole, 3...Crankshaft, 4...Electric motor, 5...Main bearing, 6...Orbiting bearing, 7...Frame, 7a...Main bearing oil supply hole, 9... Oil reservoir, 10...Oldham ring, 11...subframe, 12...leg, 3a...main shaft portion, 3b...eccentric portion, 3d...oil supply through hole, 11a...auxiliary bearing, 15...oil drain pipe, 15a...downstream portion of main bearing, 16...oil supply communication passage, 17...control valve, 17a...valve body, 17b...opening, 17c...valve seat, 17d...spring accommodating / flow passage hole, 17e...spring, S1...compression chamber, S2...back pressure chamber, S3...upper space, S4...motor chamber

Claims

1. A compressor comprising: a compression mechanism that forms a compression chamber; a shaft that transmits power to the compression mechanism; a main bearing and an orbiting bearing that support the shaft; a back pressure chamber that has an intermediate pressure between a suction pressure and a discharge pressure; a mechanism that connects the compression chamber and the back pressure chamber and adjusts the intermediate pressure; and an oil supply source on which the discharge pressure acts, an oil supply passageway extending from the oil supply source through the shaft and the main bearing and returning to the oil supply source; an oil supply system that branches off from a portion of the oil supply passage upstream of the main bearing and supplies oil to the back pressure chamber via a seal member; an oil supply communication passage that branches off at a position downstream of both the main bearing and the orbiting bearing in the oil supply passage and communicates with the back pressure chamber; a control valve that is provided in the fuel supply communication passage and adjusts the amount of fuel supplied through the fuel supply communication passage; A compressor comprising:

2. The compressor of claim 1 , wherein the control valve is configured to open in response to a pressure difference between the discharge pressure and the intermediate pressure being equal to or less than a threshold value.

3. 3. The compressor according to claim 2, wherein the oil supply from the oil supply system is oil supply according to a pressure difference between the discharge pressure and the intermediate pressure or a compressor rotation speed.

4. 2. The compressor according to claim 1, wherein the control valve comprises a valve element, a valve seat, and an elastic body that biases the valve element so that the valve element is pulled away from the valve seat and opened when a pressure difference between the discharge pressure and the intermediate pressure is small, and the valve element is brought into close contact with the valve seat and closed when the pressure difference is large.

5. The compression mechanism includes a fixed scroll having a spiral wrap standing on a base plate, and an orbiting scroll having a spiral wrap standing on an end plate, meshing with the fixed scroll to form the compression chamber, and receiving power from the shaft to perform an orbiting motion, and the compressor includes: a frame fastened to the fixed scroll and arranged to sandwich the orbiting scroll between the fixed scroll and the frame; a pressure adjustment mechanism connected to the compression chamber and the back pressure chamber, for controlling the pressure in the back pressure chamber; 2. The compressor according to claim 1, further comprising: a back pressure chamber formed by the fixed scroll, the orbiting scroll, and the frame, the back pressure chamber being disposed on a back surface of the orbiting scroll; and the compressor being a scroll compressor.

6. 6. The compressor according to claim 5, wherein the pressure adjustment mechanism includes a back pressure communication passage provided in the orbiting scroll that connects the back pressure chamber and the compression chamber, and a back pressure groove provided in the fixed scroll, the oil supply passage includes a through oil supply hole that passes through an interior of the shaft for supplying oil from the oil supply source to the main bearing, and oil supplied to the back pressure chamber is guided to the compression chamber through the back pressure communication passage and seals a gap between wraps of the orbiting scroll and the fixed scroll.

7. A refrigeration cycle device comprising the compressor according to any one of claims 1 to 6.

Images