Rotary compressor

Abstract

This rotary compressor is provided with a drive shaft (11) having an eccentric shaft part (12), a cylinder (13) in which both ends in the axial direction are closed by blocking members (14, 15), and a piston (16) into which the eccentric shaft part (12) is inserted and which eccentrically moves inside the cylinder (13). The piston (16) has steps at the axial ends thereof, each having a different axial height, and a seal material (60) for covering the steps is provided at the ends.

Description

rotary compressor

[0001] The present disclosure relates to a rotary compressor used in an air conditioner or a refrigeration device.

[0002] In conventional rotary compressors, a gap is provided between the end of the piston, which is the sliding part, and other components to allow for thermal expansion. The inside of the piston is connected to a high-pressure space, and high-pressure gas compressed by the piston leaks from inside the piston into the cylinder chamber through the gap at the end of the piston, which can cause compression loss and oil leakage due to refrigerant leakage. To address this issue, a method is available in which a groove is provided at the end of the piston and a seal material is installed, which is raised by the high pressure inside the piston to seal the gap at the end of the piston.

[0003] For example, Patent Document 1 discloses a hermetic compressor in which L-shaped notched grooves are provided in various portions of the inner wall of a cylindrical roller (piston) that rotates and slides within a cylinder chamber, and piston rings (sealing materials) are attached to circumscribe the inner periphery of the notched grooves. In Patent Document 1, the radial sealing length of the piston rings is greater than the groove width of the notched grooves. This structure allows piston rings with sufficient sealing length to be used, protruding into the inside of the rollers, so that a sealing effect can be obtained even in rotary compressors with thin rollers.

[0004] Japanese Unexamined Patent Publication No. 61-215483

[0005] In the rotary compressor disclosed in Patent Document 1, a flat seal material is tightly attached to the inner wall of the notched groove and the surface of the bearing due to the pressure difference between the inside and outside of the piston. Therefore, depending on the pressure difference between the inside and outside of the piston, the seal material may become misaligned, reducing the sealing effect.

[0006] The present disclosure has been made to solve the above-mentioned problems, and aims to prevent displacement of the sealing material and suppress a decrease in the sealing effect.

[0007] The rotary compressor according to the present disclosure is a rotary compressor including a drive shaft having an eccentric shaft portion, a cylinder whose both axial ends are blocked by blocking members, and a piston into which the eccentric shaft portion is inserted and which moves eccentrically within the cylinder, wherein the piston has steps at its axial ends that vary in axial height, and a sealing material that covers the steps is provided at the ends.

[0008] According to the present disclosure, it is possible to prevent displacement of the sealing material and suppress a decrease in the sealing effect.

[0009] 1 is a cross-sectional view parallel to the axial direction of a rotary compressor according to a first embodiment. FIG. 2 is a cross-sectional view parallel to the axial direction of a compression mechanism part of the rotary compressor according to the first embodiment. FIG. 3 is a top view of a cylinder of the rotary compressor according to the first embodiment. FIG. 4 is a cross-sectional view parallel to the axial direction of a piston and a sealing material of the rotary compressor according to the first embodiment. FIG. 5 is a top view of a piston of the rotary compressor according to the first embodiment. FIG. 6 is a top view of a sealing material of the rotary compressor according to the first embodiment. FIG. 7 is a cross-sectional view parallel to the axial direction of a compression mechanism part of a rotary compressor according to a first modified example of the first embodiment. FIG. 8 is a cross-sectional view parallel to the axial direction of a compression mechanism part of a rotary compressor according to a second embodiment. FIG. 9 is a cross-sectional view parallel to the axial direction of a piston and a sealing material of the rotary compressor according to the second embodiment. FIG. 10 is a top view of a piston of the rotary compressor according to the second embodiment. FIG. 11 is a top view of a sealing material of the rotary compressor according to the second embodiment. FIG. 12 is a cross-sectional view parallel to the axial direction of a compression mechanism part of a rotary compressor according to a third embodiment. FIG. 13 is a cross-sectional view parallel to the axial direction of a piston and a sealing material of the rotary compressor according to the third embodiment. FIG. 14 is a top view of a piston of the rotary compressor according to the third embodiment. FIG. 15 is a top view of a sealing material of the rotary compressor according to the third embodiment. FIG. 10 is a side view of a piston and a sealing material of a rotary compressor according to embodiment 4. FIG. 11 is a cross-sectional view parallel to the axial direction of the piston and the sealing material of a rotary compressor according to embodiment 4. FIG. 12 is a top view of a piston of a rotary compressor according to embodiment 4. FIG. 13 is a cross-sectional view parallel to the axial direction of the piston and the sealing material of a rotary compressor according to modified example 2 of embodiment 4. FIG. 14 is a top view of a piston of a rotary compressor according to modified example 2 of embodiment 4. FIG. 15 is a cross-sectional view parallel to the axial direction of the piston and the sealing material of a rotary compressor according to modified example 3 of embodiment 4. FIG. 16 is a top view of a piston of a rotary compressor according to modified example 3 of embodiment 4.

[0010] A rotary compressor according to an embodiment of the present disclosure will be described below with reference to the drawings. Note that the invention according to the present disclosure is not limited to the embodiment. The drawings are schematic diagrams. In addition, in the present disclosure, the rotary compressor will be described as an example of a hermetic compressor.

[0011] Embodiment 1. FIG. 1 is a cross-sectional view parallel to the axial direction of a rotary compressor 100 according to Embodiment 1. A cross-sectional view parallel to the axial direction is a cross-sectional view in the radial direction. FIG. 2 is a cross-sectional view parallel to the axial direction of the compression mechanism 10 of the rotary compressor 100 according to Embodiment 1. FIG. 3 is a top view of the cylinder 13 of the rotary compressor 100 according to Embodiment 1. Note that in this embodiment, the rotary compressor 100 will be described using a single rotary compressor having one cylinder 13, but compressors other than single rotary compressors may also be applied. In other words, the rotary compressor 100 according to this embodiment is not limited in the number of cylinders or the configuration of the compression mechanism. Rotary compressors include, for example, those in which the vanes and pistons are separate. Rotary compressors also include, for example, swing compressors in which the vanes and rollers are integrated.

[0012] The rotary compressor 100 includes a sealed container 1. The sealed container 1 is closed at both ends and has, for example, a cylindrical shape. As shown in Fig. 1, the rotary compressor 100 includes a compression mechanism 10, an electric motor 20, a suction pipe 40, a discharge pipe 42, and an oil reservoir 50.

[0013] The compression mechanism 10 is provided inside a sealed container 1, which is a housing of the rotary compressor 100. In the compression mechanism 10, a piston 16 moves eccentrically within a cylinder chamber 30 due to an eccentric shaft portion 12 provided on a main shaft 11, thereby compressing the sucked refrigerant.

[0014] As shown in FIG. 2 , the compression mechanism 10 of the rotary compressor 100 includes a main shaft 11 having an eccentric shaft portion 12, a cylinder 13 whose axial ends are closed by an upper bearing 14 and a lower bearing 15, a piston 16 whose inner circumferential surface is fitted with the eccentric shaft portion 12 and which moves eccentrically within the cylinder 13, an annular seal 60 provided at the axial end of the piston 16, a vane 17 fitted into a vane groove provided within the cylinder 13, and a discharge muffler 18 provided in the upper bearing 14. The main shaft 11 is a drive shaft, and the upper bearing 14 and lower bearing 15 are closing members that close the axial ends of the internal space of the cylinder 13. The compression mechanism 10 includes an upper bearing 14 and a lower bearing 15 above and below the cylinder 13, respectively, that support the rotation of the main shaft 11. The seal 60 is provided between the upper bearing 14 and the piston 16 and moves eccentrically with the piston 16 to suppress the flow of fluid between the upper bearing 14 and the piston 16. The fluid is at least one of a refrigerant and an oil.

[0015] The axial direction is the axial length direction of the main shaft 11. The axial direction is the longitudinal direction of the sealed container 1. The rotary compressor 100 in the present disclosure is installed so that the axial direction is the up-down direction. In a longitudinal cross-sectional view such as FIG. 1 , the axial direction is the up-down direction in the drawing, and the radial direction is the left-right direction in the drawing. The up-down direction in the drawing is the upper side of the sealed container 1, and the down-down direction in the drawing is the lower side of the sealed container 1. Note that the installation method of the rotary compressor 100 is not limited to this; for example, the rotary compressor 100 may be installed horizontally.

[0016] As shown in Fig. 1, the electric motor unit 20 is provided inside the sealed container 1 and is provided above the compression mechanism unit 10. The electric motor unit 20 has a rotor 21 provided on the main shaft 11 and a stator 22 fixed to the inner surface of the sealed container 1. The electric motor unit 20 drives the compression mechanism unit 10 via the main shaft 11.

[0017] The suction pipe 40 is provided on the side surface of the sealed container 1 and is connected to a suction port 41 provided in the cylinder 13. The cylinder chamber 30 draws in the refrigerant through the suction pipe 40.

[0018] The discharge pipe 42 is provided on the upper surface of the inside of the sealed container 1 in the axial direction. The discharge pipe 42 discharges the refrigerant compressed in the cylinder chamber 30 from the inside of the sealed container 1 to the outside of the sealed container 1. The outside of the sealed container 1 is, for example, a condenser of the refrigerant circuit.

[0019] The oil reservoir 50 is provided at the bottom of the sealed container 1. In the present disclosure, the oil reservoir 50 is provided at the lower part of the sealed container 1 in the axial direction. A part of the compression mechanism 10 is immersed in the oil in the oil reservoir 50.

[0020] The compression mechanism 10 will now be described. As shown in Fig. 2, the eccentric shaft 12 is provided on the main shaft 11 and rotates eccentrically from the center of the main shaft 11 as the main shaft 11 rotates. The eccentric shaft 12 transmits the rotational force transmitted from the electric motor 20 to the main shaft 11 to the piston 16. The eccentric shaft 12 is formed integrally with the main shaft 11 using the same member. Note that the eccentric shaft 12 may be formed, for example, as a separate member from the main shaft 11 and attached to the main shaft 11.

[0021] The cylinder 13 has a cylindrical shape with a through hole in the center and both axial ends closed by bearings. The bearings include a first bearing and a second bearing different from the first bearing. The first bearing is the upper bearing 14 provided on the electric motor unit 20 side in the axial direction in FIG. 2. The second bearing is the lower bearing 15 provided on the oil reservoir 50 side in the axial direction in FIG. 2. That is, the upper bearing 14 is attached to the upper end of the cylinder 13, and the lower bearing 15 is attached to the lower end of the cylinder 13. Note that members other than the upper bearing 14 and the lower bearing 15 may be used as the closing member.

[0022] The upper bearing 14 and the lower bearing 15 have annular flexible grooves 14a, 15a at their respective ends. The flexible grooves 14a, 15a are grooves for forming thin annular portions provided to receive, on a surface, deflection caused by rotation of the main shaft 11. As shown in Fig. 2, the flexible grooves 14a, 15a are provided at the end of the upper bearing 14 and the end of the lower bearing 15, respectively. The flexible grooves 14a, 15a are provided so as to surround the inner circumferential surfaces of the bearings.

[0023] The space formed by the cylinder 13, the upper bearing 14, and the lower bearing 15 is a cylinder chamber 30. The cylinder chamber 30 is inside the cylinder 13 and is surrounded by the inner circumferential surface of the cylinder 13 and the outer circumferential surface of the piston 16.

[0024] The piston 16 is provided inside the cylinder 13. That is, the piston 16 is provided inside the cylinder chamber 30. The piston 16 has an annular shape with a through-hole at the center. The piston 16 has an eccentric shaft portion 12 inside the inner circumferential surface of the piston 16.

[0025] The eccentric shaft portion 12 rotates together with the main shaft 11, causing the piston 16 to move eccentrically within the cylinder chamber 30. Due to this eccentric movement, part of the outer circumferential surface of the piston 16 slides against the inner circumferential surface of the cylinder chamber 30. The piston 16 moves eccentrically together with the eccentric shaft portion 12, compressing the refrigerant in the cylinder chamber 30.

[0026] The upper end of the piston 16 is the upper end of the piston 16 in Figure 2. The upper end of the piston 16 faces the upper bearing 14. The upper end of the piston 16 has a top surface and a side surface. The top surface of the piston 16 is a surface that faces the upper bearing 14 in Figure 2 and extends in a direction perpendicular to the axial direction. The side surfaces of the piston 16 are surfaces that extend in the axial direction and are provided on the left and right sides of the piston 16 in Figure 2. The piston 16 has an inner peripheral side surface and an outer peripheral side surface. The inner peripheral side surface of the piston 16 faces the eccentric shaft portion 12, and the outer peripheral side surface of the piston 16 faces the cylinder 13.

[0027] Main shaft 11 has a cavity 19 extending in the axial direction inside main shaft 11. Cavity 19 is provided in the axial direction from the lower end of main shaft 11 to a position above compression mechanism 10. Cavity 19 is a passage for supplying oil to lubricate compression mechanism 10.

[0028] Cavity 19 has a plurality of branch passages 19a, 19b, 19c that penetrate from cavity 19 toward the outer circumferential surface of main shaft 11 in the radial direction of main shaft 11. Branch passages 19a, 19b, 19c are provided at the positions of upper bearing 14, piston 16, and lower bearing 15, respectively. Branch passages 19a, 19b, 19c are provided so that oil is supplied to rotating parts in compression mechanism 10 and parts that come into contact with the rotating parts.

[0029] In the main shaft 11, the branch passages 19a, 19b, 19c function not only as oil supply passages but also as part of a centrifugal pump that generates centrifugal force and uses the centrifugal force to suck up oil.

[0030] The oil supplied through the branch passages 19 a , 19 b , and 19 c reduces friction occurring between the piston 16 , the main shaft 11 , the upper bearing 14 , and the lower bearing 15 .

[0031] As shown in FIG. 3 , the vane 17 moves while remaining in contact with the outer circumferential surface of the piston 16, which moves eccentrically within the cylinder chamber 30. A vane groove extending radially of the cylinder 13 is formed in the cylinder 13, and the vane 17 is slidably held in the vane groove. The back side of the vane 17, which is the outer circumferential side of the cylinder 13, is open to the space containing the discharge gas atmosphere of the sealed container 1. The vane 17 is pressed against the piston 16 by the high-pressure refrigerant released into the sealed container 1. The vane 17 slides horizontally within the vane groove in conjunction with the movement of the piston 16, and serves to separate the low-pressure space and high-pressure space of the cylinder chamber 30. The suction-side space 31 is the low-pressure space of the cylinder chamber 30 to which the suction port 41 is connected. The compression-side space 32 is the high-pressure space of the cylinder chamber 30 to which a discharge port (not shown) is connected.

[0032] The cylinder 13 has a hole that penetrates the cylinder 13 in the radial direction, forming a suction port 41. As shown in Figure 1, the suction port 41 is connected to a suction pipe 40, and suction refrigerant is drawn from the suction pipe 40 into the cylinder chamber 30.

[0033] 2, the discharge muffler 18 is provided on the upper bearing 14, and discharges the compressed refrigerant discharged from a discharge port (not shown) into the inside of the sealed container 1. Then, the compressed refrigerant discharged into the inside of the sealed container 1 is released into the discharge pipe 42.

[0034] Fig. 4 is a cross-sectional view parallel to the axial direction of the piston 16 and the sealing material 60 of the rotary compressor 100 according to the first embodiment. Fig. 4 is a partially enlarged view of the piston 16 and the sealing material 60 of Fig. 2. Fig. 5 is a top view of the piston 16 of the rotary compressor 100 according to the first embodiment. Fig. 6 is a top view of the sealing material 60 of the rotary compressor 100 according to the first embodiment.

[0035] As shown in FIG. 4 , in the first embodiment, the piston 16 has a groove formed at its upper end, which forms a step of varying height in the axial direction. In the rotary compressor 100 in the first embodiment, the piston 16 has a groove formed on its inner circumferential side. In the first embodiment, the step of the piston 16 is formed by step-forming portions 16 a and 16 b. The different height portions of the step of the piston 16 are portions that form steps with different axial heights, and refer to the step-forming portions 16 a and 16 b in the first embodiment. As shown in FIG. 5 , the piston 16 has an annular shape, and the step-forming portion 16 a is formed on the inner circumferential side of the piston 16, and the step-forming portion 16 b is formed on the outer circumferential side of the piston 16.

[0036] 4, in the axial direction, the height of the step-forming portion 16b of the piston 16 is higher than the height of the step-forming portion 16a. In other words, the axial height of the piston 16 is lower on the inner peripheral side of the piston 16 than on the outer peripheral side of the piston 16. As a result, the piston 16 has a step whose axial height changes in the radial direction of the piston 16.

[0037] Since the steps have different axial heights, the parts of the steps that have a higher axial height protrude upward compared to the parts of the steps that have a lower axial height. The steps have side surfaces that connect the upper surfaces of the parts with a higher axial height and the lower axial height. In FIG. 4 , the surface that connects the upper surface of the step-forming portion 16a and the upper surface of the step-forming portion 16b is the side surface of the step. The side surface of the step is a surface that extends in the axial direction. The surface that constitutes the step is, for example, a surface that includes the upper surface of the part with a higher axial height, the upper surface of the part with a lower axial height, and the side surface of the step.

[0038] As shown in FIG. 4 , in the first embodiment, the piston 16 has an L-shaped radial cross section at the upper end of the piston 16. The sealing material 60 according to the first embodiment has an L-shaped radial cross section that is upside down. That is, the sealing material 60 is provided at the upper end of the piston 16 and is shaped to fit between the piston 16 and the upper bearing 14. In particular, the sealing material 60 is shaped to fit with a step on the piston 16. Fitting is not limited to a state in which the piston 16 and the sealing material 60 are fixed in close contact with each other across their entire surfaces. The shape that fits with the step on the piston 16 means that the end of the sealing material 60 facing the piston 16 has a shape that complements the shape of the step. Specifically, the piston 16 and the sealing material 60 each have a high axial height portion and a low axial height portion, and the low portion of the sealing material 60 covers the high portion of the piston 16, and the high portion of the sealing material 60 covers the low portion of the piston 16. The piston 16 and the seal material 60 are annular and have the same center, so that the radial direction of the piston 16 and the radial direction of the seal material 60 are the same.

[0039] The sealing material 60 continuously covers the step-forming portions 16a and 16b, and is shaped to cover the upper end of the piston 16. In other words, the sealing material 60 covers the steps of the piston 16, that is, it covers each end of the different height portions of the steps of the piston 16. The sealing material 60 covering the steps of the piston 16 means that the end faces of the sealing material 60 face the surfaces that form the steps of the piston 16. Note that covering does not necessarily mean covering the entire end face of a certain end face, and may mean, for example, covering only a portion of a certain end face.

[0040] As shown in FIG. 4, the sealing material 60 is composed of sealing material forming portions 60a and 60b. The sealing material 60 has a shape including a sealing material forming portion 60a, which is a portion with a higher axial height, and a sealing material forming portion 60b, which is a portion with a lower axial height. The portion with a higher axial height is a first sealing material forming portion. The portion with a lower axial height is a second sealing material forming portion, and the second sealing material forming portion has a lower axial height than the first sealing material forming portion. As shown in FIG. 6, the sealing material 60 has an annular shape. The sealing material 60 has a sealing material forming portion 60a on the inner circumferential side and a sealing material forming portion 60b on the outer circumferential side.

[0041] It should be noted that the sealing material 60 of the present disclosure is a sealing material made of a single material, but the sealing material 60 may also be made such that the sealing material forming portions 60a and 60b are independent components that are joined together to form a single unit.

[0042] Furthermore, the lower portion of the sealing material 60 covers the portion of the step of the piston 16 that is closest to the upper bearing 14. That is, as shown in Figure 4, of the steps of the piston 16, the step forming portion 16b is closest to the upper bearing 14, and the sealing material forming portion 60b covers the step forming portion 16b.

[0043] The seal material 60 is generally made of resin, but may be made of a lightweight metal material that is slidable.

[0044] 2, in the first embodiment, the outer diameter of the sealing material 60 is the same as the outer diameter of the piston 16. The outer diameter of the piston 16 corresponds to the outer peripheral surface of the piston 16 that faces the cylinder chamber 30. The outer diameter of the sealing material 60 is the diameter relative to the outer periphery of the sealing material 60 on the outermost side, i.e., the maximum diameter of the sealing material 60. The inner diameter of the sealing material 60 is the diameter relative to the inner periphery of the sealing material 60 on the innermost side, i.e., the diameter of the through-hole portion.

[0045] The piston 16 and the sealing material 60 rotate together with the eccentric shaft portion 12, with the outer diameter surface of the piston 16 and the outer diameter surface of the sealing material 60 coinciding with each other. At this time, the axial height of the piston 16 and the sealing material 60 stacked together is shorter than the axial height of the cylinder 13. As a result, in the rotary compressor 100, as in conventional rotary compressors, a gap is provided between the upper bearing 14 and the sealing material 60, providing a space in which the sealing material 60 can float.

[0046] In this embodiment, the outer diameter of the seal material 60 is the same as the outer diameter of the piston 16 , but the outer diameter of the seal material 60 does not necessarily have to be completely the same as the outer diameter of the piston 16 .

[0047] In the radial direction, the width of the sealing material 60 is the sum of the widths of the sealing material forming portion 60a and the sealing material forming portion 60b. The radial width of the sealing material 60 is called the seal length. It is desirable that the inner diameter of the sealing material 60 is the same as the inner diameter of the piston 16. This is because the seal length is the same as the radial width of the piston 16, ensuring a long seal length. Furthermore, by making the inner diameter of the sealing material 60 slightly smaller than the inner diameter of the piston 16, the seal length becomes longer than the radial width of the piston 16, thereby further improving the sealing effect. Conversely, by making the inner diameter of the sealing material 60 slightly larger than the inner diameter of the piston 16, the seal length becomes shorter than the radial width of the piston 16, thereby reducing the contact area between the sealing material 60 and the upper bearing 14 and reducing friction between the sealing material 60 and the upper bearing 14.

[0048] Next, the operation of the rotary compressor 100 according to the first embodiment will be described.

[0049] The operation of the rotary compressor 100 for compressing a refrigerant will be described. In the rotary compressor 100, when the electric motor unit 20 operates, the eccentric shaft unit 12 moves via the main shaft 11 connected to the electric motor unit 20, causing the piston 16 to perform eccentric motion.

[0050] In the rotary compressor 100, low-pressure refrigerant is drawn into the cylinder chamber 30 through the suction port 41. The cylinder chamber 30 is divided into a suction-side space 31 and a compression-side space 32 by the vane 17, and the low-pressure refrigerant drawn into the suction port 41 is introduced into the suction-side space 31. As the piston 16 moves eccentrically within the cylinder chamber 30, the volume of the refrigerant drawn into the cylinder chamber 30 changes and is compressed.

[0051] The compressed high-pressure refrigerant present in the compression-side space 32 is discharged from the discharge port through the discharge muffler 18 into the inside of the sealed container 1. The refrigerant is then released from the inside of the sealed container 1 to the discharge pipe 42. The inside of the sealed container 1 is filled with high-pressure refrigerant.

[0052] Oil is supplied from the oil reservoir 50 , which is a high-pressure space, to the eccentric shaft portion 12 inside the piston 16 through the branch passage 19 b of the cavity portion 19 .

[0053] With this configuration, high-pressure refrigerant and supplied high-pressure oil are present in the space on the inner circumferential side of the piston 16 .

[0054] The pressure inside the piston 16 is higher than the pressure in the cylinder chamber 30 outside the piston 16. The pressure in the cylinder chamber 30 is lower than the discharge pressure during the compression process. Therefore, high-pressure refrigerant and high-pressure oil flow into the gap between the piston 16 and the upper bearing 14. In other words, there is a possibility that the fluid may leak into the cylinder chamber 30 through the gap.

[0055] In the rotary compressor 100 according to the first embodiment, a seal 60 is provided between the piston 16 and the upper bearing 14. When the seal 60 floats due to the pressure difference between the inside and outside of the piston 16, the seal 60 is pressed against the end face of the upper bearing 14 and the side surface of the step. In other words, the floated seal 60 closes the gap between the upper bearing 14 and the upper end of the piston 16. Because the gap is closed by the seal 60, leakage of fluid into the cylinder chamber 30 can be suppressed.

[0056] In the first embodiment, the rotary compressor 100 has been described using a single rotary compressor. The present disclosure is also effective in a twin rotary compressor having two cylinders. As a first modification of the first embodiment, a rotary compressor 110 that is a twin rotary compressor will be described. Fig. 7 is a cross-sectional view parallel to the axial direction of the compression mechanism 10 of the rotary compressor 110 according to the first modification of the first embodiment.

[0057] The rotary compressor 110 has two cylinder chambers, each of which is formed by a cylinder, arranged in the axial direction. As shown in Fig. 7 , the rotary compressor 110 includes a first cylinder 131 and a second cylinder 132.

[0058] The intermediate plate 70 closes each end face of the first cylinder 131 and the second cylinder 132 in the axial direction, forming each cylinder chamber. The intermediate plate 70 is a closing member that closes each cylinder chamber in the axial direction. The first cylinder chamber 301 is formed by closing the first cylinder 131 with the upper bearing 14 and the intermediate plate 70. The intermediate plate 70 contacts the end face of the first cylinder 131 on the lower bearing 15 side. The second cylinder chamber 302 is formed by closing the second cylinder chamber 302 with the lower bearing 15 and the intermediate plate 70. The intermediate plate 70 contacts the end face of the second cylinder 132 on the upper bearing 14 side. Therefore, the intermediate plate 70 is installed between the first cylinder chamber 301 and the second cylinder chamber 302. As a result, the second cylinder chamber 302 is located on the opposite side of the first cylinder chamber 301 in the axial direction.

[0059] The first eccentric shaft portion 121 provided on the first cylinder 131 and the second eccentric shaft portion 122 provided on the second cylinder 132 are provided at phases opposite to each other by 180 degrees with respect to the main shaft 11 .

[0060] The intermediate plate 70 has an intermediate plate hole 71 that penetrates the main shaft 11. A sealant 60 is provided between the intermediate plate 70 and the piston 16 provided in the second cylinder chamber 302. If the sealant length is insufficient, the sealant 60 will not be able to fully close the intermediate plate hole 71. This could result in fluid flowing from inside the piston 16 into the first cylinder chamber 301 and the second cylinder chamber 302 through the intermediate plate hole 71, resulting in refrigerant and oil leakage. Furthermore, because the intermediate plate hole 71 is a high-pressure space similar to the space inside the piston 16, fluid could leak from the intermediate plate hole 71 itself.

[0061] Here, the sealing material 60 of the rotary compressor 110 is shaped to cover each of the different height portions of the step of the piston 16, and is shaped not to be affected by the groove width of the piston 16. This allows the sealing material 60 to ensure a sealing length up to the intermediate plate hole 71, and suppresses a decrease in the sealing effect.

[0062] As described above, the rotary compressor 100 according to the first embodiment and the rotary compressor 110 according to the first modification of the first embodiment include a main shaft 11 having an eccentric shaft portion 12, a cylinder 13 whose axial ends are closed by an upper bearing 14 and a lower bearing 15, and a piston 16 into which the eccentric shaft portion 12 is inserted and which moves eccentrically within the cylinder 13. The piston 16 has steps with different axial heights at its axial ends. The rotary compressor 100 according to the first embodiment and the rotary compressor 110 according to the first modification of the first embodiment further include a seal 60 at the end of the piston 16 that covers the steps of the piston 16. The seal 60 has a shape that has a portion with a higher axial height on the inner circumferential side and a portion with a lower axial height on the outer circumferential side. The lower portion of the seal 60 covers the portion of the steps of the piston 16 that is closest to the upper bearing 14.

[0063] In conventional rotary compressors such as those described in Patent Document 1, if the pressure difference between the inside and outside of the piston 16 is insufficient, a portion of the sealing material may not float and may tilt if the sealing material has a conventional shape. Here, in the rotary compressor 100 according to Embodiment 1 and the rotary compressor 110 according to Modification 1, the piston 16 and the sealing material 60 are configured so that steps of different heights fit together, preventing the sealing material 60 from tilting. This prevents the sealing material 60 from shifting position and suppresses a decrease in sealing effectiveness. Furthermore, even if the entire sealing material 60 does not float, the sealing material 60 rests on each end of the step of the piston 16, preventing the gap between the upper end of the piston 16 and the upper bearing 14 from widening, thereby suppressing a decrease in sealing effectiveness compared to conventional methods.

[0064] In conventional rotary compressors, the seal length is determined by the groove width of the piston 16, and therefore it is not possible to ensure that the seal length is longer than the groove width. However, in the rotary compressor 100 according to the first embodiment and the rotary compressor 110 according to the first modification, the seal material 60 is shaped to cover each of the different height portions of the step of the piston 16, and therefore the seal length can be ensured to be long without being affected by the groove width. Because the sealing effect is proportional to the seal length, the rotary compressor 100 according to the first embodiment can achieve a better sealing effect than conventional rotary compressors.

[0065] Furthermore, as described above, even if the diameter of the piston 16 is reduced, the seal length can be ensured regardless of the size of the piston 16 and the width of the groove provided in the piston 16, which also contributes to making the compressor smaller and increasing its capacity.

[0066] The seal material 60 has an L-shaped cross section in the radial direction.

[0067] Because the piston 16 and the sealing material 60 have an L-shaped radial cross section, a protrusion can be formed on the outer diameter side of the piston 16, and a protrusion can be formed on the inner diameter side of the sealing material 60. As a result, the piston 16 and the sealing material 60 have only one protrusion, and therefore the thickness of each protrusion can be increased, thereby increasing the strength of the parts.

[0068] The outer diameter of the seal member 60 is the same as the outer diameter of the piston 16 , which corresponds to the outer peripheral surface of the piston 16 facing the cylinder chamber 30 .

[0069] Since the outer diameter of the piston 16 and the outer diameter of the sealing material 60 match, the gap between the outer diameter surface of the piston 16 and the inner diameter surface of the cylinder 13 and the gap between the outer diameter surface of the sealing material 60 and the inner diameter surface of the cylinder 13 also match, preventing fluid from leaking from the compression side space 32 to the suction side space 31 and suppressing a decrease in the sealing effect.

[0070] If the seal length is short, the flexible groove 14a may be exposed to the outside of the sealing material 60. If the flexible groove 14a is located outside the sealing material 60, the cylinder chamber 30 and the inside of the piston 16 are in communication with each other through the flexible groove 14a, resulting in refrigerant and oil leakage. Here, in the rotary compressor 100 according to the first embodiment and the rotary compressor 110 according to the first modified example of the first embodiment, the outer diameter of the sealing material 60 is the same as the outer diameter of the piston 16, so that the sealing material 60 can block the flexible groove 14a as well, thereby suppressing a decrease in the sealing effect.

[0071] In the present disclosure, the upper bearing 14 and the lower bearing 15 have the flexible grooves 14a and 15a, respectively, but they do not necessarily have to have the flexible grooves 14a and 15a.

[0072] The cross-sectional shape of the cylinder 13, the piston 16 and the seal material 60 in a direction perpendicular to the radial direction is a circle with a hole in the center, but it does not have to be a perfect circle.

[0073] Second Embodiment Next, a second embodiment will be described. Fig. 8 is a cross-sectional view parallel to the axial direction of the compression mechanism 10 of a rotary compressor 200 according to the second embodiment. Fig. 9 is a cross-sectional view parallel to the axial direction of a piston 161 and a sealing material 601 of the rotary compressor 200 according to the second embodiment. Fig. 9 is a partially enlarged view of the piston 161 and the sealing material 601 of Fig. 8. Fig. 10 is a top view of the piston 161 of the rotary compressor 200 according to the second embodiment. Fig. 11 is a top view of the sealing material 601 of the rotary compressor 200 according to the second embodiment. Note that the same components as those of the first embodiment are designated by the same reference numerals, and description thereof will be omitted.

[0074] The rotary compressor 200 according to the second embodiment differs from the first embodiment in that the radial cross section of the piston 161 is U-shaped and the radial cross section of the sealing material 601 is T-shaped.

[0075] As shown in Fig. 8, in the second embodiment, piston 161 has a groove formed in the upper end portion thereof, and has steps of different heights in the axial direction. As shown in Fig. 9, piston 161 according to the second embodiment has a groove formed between the inner periphery and the outer periphery of piston 161 at the upper end portion of piston 161. The groove formed in piston 161 is provided in the center of the width of the upper end portion of piston 161. Piston 161 has protrusions on both the inner and outer periphery sides at the upper end portion of piston 161.

[0076] In the second embodiment, the step of the piston 161 is made up of step forming portions 161a, 161b, and 161c. As shown in Fig. 10, the piston 161 has step forming portion 161b on the inner circumferential side, step forming portion 161a in the widthwise center, and step forming portion 161c on the outer circumferential side.

[0077] As shown in Fig. 9, the height of step forming portion 161b and the height of step forming portion 161c are higher in the axial direction than the height of step forming portion 161a. In other words, in the axial direction, the height of the outer circumferential side of piston 161 and the height of the inner circumferential side of piston 161 are higher than the height of the center of the width of piston 161. In Fig. 9, the surface connecting the upper surface of step forming portion 161a with the upper surface of step forming portion 161b and the surface connecting the upper surface of step forming portion 161a with the upper surface of step forming portion 161c are side surfaces of the step.

[0078] 9 , in the second embodiment, piston 161 has a U-shaped cross section in the radial direction at the upper end of piston 161. Since sealing material 601 is shaped to fit between piston 161 and upper bearing 14, sealing material 601 has a T-shaped cross section in the radial direction.

[0079] The sealing material 601 has a shape that covers the upper end portions of the step forming portions 161 a, 161 b, and 161 c. In other words, the sealing material 601 covers the end portions of the steps of the piston 161 at different heights.

[0080] As shown in Fig. 9, the sealing material 601 has an annular shape and is composed of sealing material forming portions 601a, 601b, and 601c. The sealing material 601 has a protruding portion with a high axial height between the inner periphery of the sealing material 601 and the outer periphery of the sealing material 601. The protruding portion of the sealing material 601 is provided in the center of the sealing material 601. The protruding portion of the sealing material 601 is the sealing material forming portion 601a. ​​As shown in Fig. 11, the sealing material 601 is provided with the sealing material forming portion 601b on the inner periphery side, the sealing material forming portion 601a in the center, and the sealing material forming portion 601c on the outer periphery side.

[0081] Focusing on the sealing material forming portion 601a and the sealing material forming portion 601c, the sealing material 601 has a shape having the sealing material forming portion 601a, which is a portion with a higher axial height on the inner side, and the sealing material forming portion 601c, which is a portion with a lower axial height on the outer side.

[0082] Focusing on the sealing material forming portion 601a and the sealing material forming portion 601b, the sealing material 601 has the sealing material forming portion 601b, which is a portion with a lower axial height, located more inward than the sealing material forming portion 601a, which is a portion with a higher axial height. In other words, the sealing material 601 has a shape that further has a portion with a lower axial height located more inward than the portion with a higher axial height of the sealing material 601.

[0083] In the second embodiment, the sealing material forming portion 601b and the sealing material forming portion 601c have the same height in the axial direction.

[0084] Furthermore, the seal material 601 has a seal material forming portion 601b and a seal material forming portion 601c covering the portion of the step of the piston 161 that is closest to the upper bearing 14.

[0085] Next, the operation of the rotary compressor 200 according to the second embodiment will be described.

[0086] The rotary compressor 200 that compresses the refrigerant and the sealing material 601 basically operate in the same manner as in the first embodiment, but the different shape from the first embodiment causes the sealing material 601 to float in a different manner. The sealing material 601 floats due to the pressure difference between the space on the inner periphery of the piston 161 and the space on the outer periphery of the piston 161, and the sealing material 601 is pressed against the end face of the upper bearing 14 and the side of the step that is on the side of the step forming portion 161c. Here, the high-pressure fluid inside the piston 161 flows sequentially between the step forming portion 161b and the sealing material forming portion 601b, and between the step forming portion 161b and the sealing material forming portion 601a, and then flows between the step forming portion 161a and the sealing material forming portion 601a, causing the sealing material forming portion 601a to float.

[0087] 9, in order to ensure a space for supplying a fluid between the step-forming portion 161a and the sealant-forming portion 601a, the height (i.e., the axial depth) of the step-forming portion 161a, which is a groove, is preferably slightly greater than the axial height of the sealant-forming portion 601a inserted into this groove. Also, in order to ensure a space for supplying a fluid between the side of the step on the step-forming portion 161b side and the sealant-forming portion 601a, as shown in FIG. 9, the radial width of the step-forming portion 161a is preferably slightly greater than the radial width of the sealant-forming portion 601a.

[0088] The piston 161 of the rotary compressor 200 according to the second embodiment has a U-shaped cross section in the radial direction. The seal member 601 of the rotary compressor 200 according to the second embodiment has a T-shaped cross section in the radial direction.

[0089] As a result, even if the sealing material 601 does not rise sufficiently, the sealing material 601 rests on each end of the step of the piston 161, preventing the sealing material 601 from shifting position. This prevents a decrease in the sealing effect. Furthermore, the sealing material 601 closes the gap between each end of the step of the piston 161 and the upper bearing 14, preventing refrigerant and oil leakage.

[0090] In some cases, a reed valve is used at the discharge port. The reed valve is provided to cover the discharge port provided in the cylinder 13. The reed valve prevents backflow from inside the sealed container 1 into the compression-side space 32 when the pressure in the compression-side space 32 is lower than the pressure inside the sealed container 1 outside the discharge port during the refrigerant compression process. When the pressure in the compression-side space 32 becomes higher than the pressure inside the sealed container 1 outside the discharge port, the reed valve is pushed up by the high pressure in the compression-side space 32 when the refrigerant can be sufficiently compressed, and the compressed refrigerant is released from the discharge port. Here, when the reed valve is pushed up, the pressure in the compression-side space 32 becomes higher than the pressure inside the piston 161 having the eccentric shaft portion 12, and the sealing material 601 may be pressed against the piston 161 from the outer periphery toward the inner periphery of the piston 161.

[0091] Here, in the rotary compressor 200 of the second embodiment, the sealing material 601 is T-shaped, so that the sealing material forming portion 601a catches on the step forming portion 161b, which is a protruding portion on the inner circumferential side of the piston 161, and it is possible to prevent the sealing material 601 from coming into contact with the eccentric shaft portion 12. Furthermore, because the sealing material 601 is always present between the upper bearing 14 and the upper end portion of the piston 161, even if the sealing material 601 is pressed against the inner circumferential side of the piston 161 from the outer circumferential side of the piston 161, the sealing length can be ensured.

[0092] Third Embodiment Next, a third embodiment will be described. Fig. 12 is a cross-sectional view parallel to the axial direction of the compression mechanism 10 of a rotary compressor 300 according to the third embodiment. Fig. 13 is a cross-sectional view parallel to the axial direction of a piston 162 and a seal 602 of a rotary compressor 300 according to the third embodiment. Fig. 13 is a partially enlarged view of the piston 162 and the seal 602 of Fig. 8. Fig. 14 is a top view of the piston 162 of a rotary compressor 300 according to the third embodiment. Fig. 15 is a top view of the seal 602 of a rotary compressor 300 according to the third embodiment. Note that the same components as those of the first and second embodiments are designated by the same reference numerals, and description thereof will be omitted.

[0093] The rotary compressor 300 according to the third embodiment differs from the first embodiment in that the radial cross section of the piston 162 is T-shaped and the radial cross section of the sealing material 602 is U-shaped.

[0094] As shown in Fig. 12, in the third embodiment, piston 162 has a groove formed in the upper end portion of piston 162, and has steps of different heights in the axial direction. As shown in Fig. 13, piston 162 according to the third embodiment has grooves formed on the inner periphery and outer periphery of piston 162 at the upper end portion of piston 162. At the upper end portion of piston 162, piston 162 has a protruding portion formed in the center between the inner periphery and the outer periphery.

[0095] The step of the piston 162 is made up of step forming portions 162a, 162b, and 162c. As shown in Fig. 14, the piston 162 has the step forming portion 162b on the inner circumferential side, the step forming portion 162a in the widthwise center, and the step forming portion 162c on the outer circumferential side.

[0096] 13, the height of step forming portion 162a is higher in the axial direction than the height of step forming portion 162b and the height of step forming portion 162c. In other words, in the axial direction, the height of the center of piston 162 is higher than the height of the outer circumferential side of piston 162 and the height of the inner circumferential side of piston 162. In FIG. 13, the surface connecting the upper surface of step forming portion 162a with the upper surface of step forming portion 162b and the surface connecting the upper surface of step forming portion 162a with the upper surface of step forming portion 162c are side surfaces of the step.

[0097] 13 , in the third embodiment, the piston 162 has an upside-down T-shape at the upper end of the piston 162 in a radial cross section. The sealing material 602 has a shape that fits between the piston 162 and the upper bearing 14, and therefore the sealing material 602 has an upside-down U-shape in a radial cross section.

[0098] The sealing material 602 has a shape that covers the upper end portions of the step forming portions 162a, 162b, and 162c. In other words, the sealing material 602 covers the end portions of the steps of the piston 162 at different heights.

[0099] As shown in Fig. 13, the sealing material 602 has an annular shape and is composed of sealing material forming portions 602a, 602b, and 602c. The sealing material 602 has protruding portions with a high axial height on both the inner and outer circumferential sides of the sealing material 602. The protruding portions of the sealing material 602 are the sealing material forming portions 602b and 602c. As shown in Fig. 15, the sealing material 602 has the sealing material forming portion 602b on the inner circumferential side, the sealing material forming portion 602a in the widthwise center, and the sealing material forming portion 602c on the outer circumferential side.

[0100] Focusing on the sealing material forming portion 602a and the sealing material forming portion 602b, the sealing material 602 has a shape having a sealing material forming portion 602b, which is a portion with a higher axial height on the inner side, and a sealing material forming portion 602a, which is a portion with a lower axial height on the outer side.

[0101] Focusing on the sealing material forming portion 602a and the sealing material forming portion 602c, the sealing material 602 has the sealing material forming portion 602c, which is a portion with a higher axial height, on the outer circumferential side of the sealing material forming portion 602a, which is a portion with a lower axial height. In other words, the sealing material 602 has a shape that further has a portion with a higher axial height at a position outer circumferential side than the portion with a lower axial height.

[0102] In the third embodiment, the sealing material forming portion 602b and the sealing material forming portion 602c have the same height in the axial direction.

[0103] Furthermore, the seal material 602 has a seal material forming portion 602 a that covers the portion of the step of the piston 162 that is closest to the upper bearing 14 .

[0104] Next, the operation of the rotary compressor 300 according to the third embodiment will be described.

[0105] The rotary compressor 300 that compresses the refrigerant and the sealing material 602 basically operate in the same manner as in the first and second embodiments, but the different shapes from those in the first and second embodiments cause the sealing material 602 to float in a different manner. The sealing material 602 floats due to the pressure difference between the space on the inner periphery of the piston 162 and the space on the outer periphery of the piston 162, and is pressed against the end face of the upper bearing 14 and the side of the step that is on the step-forming portion 162b side. Here, high-pressure fluid inside the piston 162 flows between the step-forming portion 162b and the sealing material-forming portion 602b, causing the sealing material-forming portion 602b to float.

[0106] The piston 162 of the rotary compressor 300 according to the third embodiment has a T-shaped cross section in the radial direction. The seal member 602 of the rotary compressor 300 according to the third embodiment has a U-shaped cross section in the radial direction.

[0107] As a result, even if the sealing material 602 does not rise sufficiently, the sealing material 602 rests on each end of the step of the piston 162, preventing the sealing material 602 from shifting position. Therefore, the rotary compressor 300 according to the third embodiment can stabilize the position of the sealing material 602 and prevent a decrease in the sealing effect. Furthermore, the sealing material 602 closes the gap between each end of the step of the piston 162 and the upper bearing 14, preventing refrigerant and oil leakage.

[0108] Furthermore, as in the second embodiment, there is a possibility that the sealing material 602 will be pressed against the piston 162 from the outer periphery of the piston 162 toward the inner periphery of the piston 162. In contrast, since the sealing material 602 is U-shaped, the sealing material forming portion 602b will catch on the step forming portion 162a, which is a protruding portion in the center of the piston 162, and it is possible to prevent the sealing material 602 from coming into contact with the eccentric shaft portion 12. Furthermore, since the sealing material 602 is always present between the upper bearing 14 and the upper end portion of the piston 162, it is possible to ensure the seal length even if the sealing material 602 is pressed against the inner periphery of the piston 162 from the outer periphery of the piston 162.

[0109] Furthermore, in the rotary compressor 300 of the third embodiment, the sealing material 602 has a U-shape, which increases the second moment of area of ​​the sealing material 602. If the cylinder chamber 30 is over-compressed, the sealing material 602 may deform inwardly of the piston 162. However, by increasing the second moment of area of ​​the sealing material 602, the amount of deformation can be suppressed.

[0110] Fourth Embodiment Next, a fourth embodiment will be described. FIG. 16 is a side view of a piston 163 and a seal material 60 of a rotary compressor 400 according to the fourth embodiment. Because FIG. 16 is a side view of the annular piston 163 and the seal material 60, the grooves formed in the piston 163 are shown with different widths, but they all have the same width in the circumferential direction of the piston 163. FIG. 17 is a cross-sectional view parallel to the axial direction of the piston 163 and the seal material 60 of the rotary compressor 400 according to the fourth embodiment. FIG. 18 is a top view of the piston 163 of the rotary compressor 400 according to the fourth embodiment. Note that the same components as those in the first to third embodiments are designated by the same reference numerals, and their description will be omitted.

[0111] As shown in Figure 16, the rotary compressor 400 of embodiment 4 differs from embodiments 1 to 3 in that a groove extending radially of the piston 163 is provided on the outer periphery of the upper end of the piston 163.

[0112] As shown in Fig. 17, in the piston 163 according to the fourth embodiment, the upper end of the piston 16 is L-shaped when viewed in a radial cross section, similar to the piston 16 according to the first embodiment. The sealing material according to the fourth embodiment is the sealing material 60 according to the first embodiment. The step of the piston 163 is formed by step-forming portions 163a and 163b. As shown in Fig. 18, the piston 163 is provided with the step-forming portion 163a on the inner circumferential side and the step-forming portion 163b on the outer circumferential side.

[0113] As shown in FIG. 18 , the piston 163 has a groove extending radially of the piston 163 at the upper end of a step-forming portion 163b, which is the outer peripheral portion of the piston 163. The radial groove provided in the step-forming portion 163b forms the step-forming portion 163c. As shown in FIG. 17 , the height of the step-forming portion 163c in the axial direction is lower than the height of the step-forming portion 163b. As shown in FIG. 18 , a plurality of step-forming portions 163c are provided at the end of the annular step-forming portion 163b. The plurality of step-forming portions 163c are spaced apart from one another in the circumferential direction of the piston 163 and are arranged at equal intervals.

[0114] The circumferential width of the step forming portion 163c is different from the circumferential width of the step forming portion 163b. For example, the circumferential width of the step forming portion 163c is shorter than the circumferential width of the step forming portion 163b. Furthermore, the total circumferential width of the plurality of step forming portions 163c is shorter than the total width of the plurality of step forming portions 163b. Note that the circumferential width of the step forming portion 163c may be longer than the circumferential width of the step forming portion 163b. Furthermore, the total circumferential width of the plurality of step forming portions 163c may be longer than the total width of the plurality of step forming portions 163b.

[0115] Although the step-forming portions 163c are provided at equal intervals on the end portion of the piston 163 in the circumferential direction, they do not have to be provided at equal intervals. For example, the piston 163 may have a portion where the step-forming portions 163c are provided at wider intervals in the circumferential direction, or may have a portion where the step-forming portions 163c are provided at narrower intervals in the circumferential direction.

[0116] Although step forming portion 163c is provided around the entire circumference of the upper end portion of piston 163, step forming portion 163c may be provided only in a portion of the upper end portion of piston 163. In particular, in the case of a swing compressor in which the direction of the piston during one rotation is fixed, step forming portion 163c may be provided only in a portion where refrigerant is likely to leak.

[0117] The operation of the rotary compressor 400 according to the fourth embodiment is the same as that of the first to third embodiments, and the sealing material 60 blocks the gap between the upper end of the piston 163 and the upper bearing 14, thereby suppressing refrigerant and oil leakage through the gap.

[0118] As described in the second embodiment, the compressed refrigerant and oil may leak from the compression-side space 32 into the suction-side space 31. Because the piston 163 has an annular shape, the refrigerant leaks in a tangential direction to the circumference of the piston 163.

[0119] A radially extending groove is provided in the step-forming portion 163b at the upper end of the piston 163, forming the step-forming portion 163c. The step-forming portion 163c extends radially and is perpendicular to the refrigerant leakage direction. Because multiple step-forming portions 163c are provided along the refrigerant leakage path, spaces of different axial heights are formed along the refrigerant leakage path. Specifically, narrow spaces formed by the sealing material 60 and the step-forming portion 163b and wide spaces formed by the sealing material 60 and the step-forming portion 163c are alternately arranged along the refrigerant leakage path. When the refrigerant flows through the refrigerant leakage path, the refrigerant repeatedly contracts and expands as it flows between narrow and wide spaces. This repeated contraction and expansion creates resistance to the flow, thereby suppressing refrigerant leakage. The step-forming portion 163c provided on the piston 163 acts as a labyrinth seal.

[0120] Furthermore, the axial height of the step-forming portion 163c is greater than the axial height of the step-forming portion 163a. ​​As shown in FIG. 17 , compared to the first embodiment, the side of the step of the piston 163 further includes a side of the step on the step-forming portion 163c side, which is a surface connecting the upper surface of the step-forming portion 163a with the upper surface of the step-forming portion 163c. The axial height of the step-forming portion 163c is sufficient to allow the side of the step on the step-forming portion 163c side to come into contact with a portion of the side of the sealing material 60 when the sealing material 60 floats up. Even if a radially penetrating groove is provided, the sealing material 60 comes into contact with the inner circumferential surface of the step-forming portion 163c, which is the side of the step on the step-forming portion 163c side, and fills the gap, thereby preventing fluid leakage through the step-forming portion 163c.

[0121] Although the piston 163 according to the fourth embodiment has an L-shaped radial cross section, the shape of the piston 163 is not limited to this. The shape of the piston 163 having a groove extending in the radial direction at the outer peripheral end of the piston 163 may be the same as the shapes of the pistons 161 and 162 according to the second and third embodiments, and will be described below as Modifications 2 and 3.

[0122] Modification 2, which is a modification of Embodiment 4, will now be described. Fig. 19 is a cross-sectional view parallel to the axial direction of piston 164 and sealing material 601 of rotary compressor 410 according to Modification 2 of Embodiment 4. Fig. 20 is a top view of piston 164 of rotary compressor 410 according to Modification 2 of Embodiment 4. Note that the same components as those of Embodiments 1 to 3 are designated by the same reference numerals, and description thereof will be omitted.

[0123] As shown in Fig. 19, the piston 164 according to Modification 2 has a U-shaped upper end portion when viewed in a radial cross section, similar to the piston 161 according to Embodiment 2. The sealing material according to Modification 2 is the sealing material 601 according to Embodiment 2. The step of the piston 164 is composed of step-forming portions 164a, 164b, and 164c. As shown in Fig. 20, the piston 164 has step-forming portion 164b on the inner circumferential side, step-forming portion 164a in the center, and step-forming portion 164c on the outer circumferential side.

[0124] As shown in Figure 20, the piston 164 has a groove extending radially of the piston 164 at the upper end of a step-forming portion 164c, which is the outer peripheral portion of the piston 164. The step-forming portion 164d is formed by the radial groove provided in the step-forming portion 164c. As shown in Figure 19, the height of the step-forming portion 164d in the axial direction is lower than the height of the step-forming portion 164c. As shown in Figure 20, a plurality of step-forming portions 164d are provided at the end of the annular step-forming portion 164c. The plurality of step-forming portions 164d are formed at intervals from one another in the circumferential direction of the piston 164 and are arranged side by side at equal intervals.

[0125] The axial height of the step-forming portion 164d is greater than the axial height of the step-forming portion 164a. As shown in FIG. 19 , compared to the second embodiment, the side of the step of the piston 164 further includes a side of the step on the step-forming portion 164d side, which is a surface connecting the upper surface of the step-forming portion 164a with the upper surface of the step-forming portion 164d. When the sealing material 601 floats, the axial height of the step-forming portion 164d is high enough to allow the side of the step on the step-forming portion 164d side to come into contact with a portion of the side of the protruding portion of the sealing material 601. Even if a radially extending groove is provided, the sealing material 601 contacts the inner circumferential surface of the step-forming portion 164d, which is the side of the step on the step-forming portion 164d side, and fills the gap, thereby preventing fluid leakage through the step-forming portion 164d.

[0126] Modification 3, which is a modification of Embodiment 4, will now be described. Fig. 21 is a cross-sectional view parallel to the axial direction of piston 165 and sealing material 602 of rotary compressor 420 according to Modification 3 of Embodiment 4. Fig. 22 is a top view of piston 165 of rotary compressor 420 according to Modification 3 of Embodiment 4. Note that the same components as those of Embodiments 1 to 3 are designated by the same reference numerals, and description thereof will be omitted.

[0127] As shown in Fig. 21 , similar to piston 162 according to embodiment 3, piston 165 according to modification 3 has a T-shaped upper end portion when viewed in a radial cross section. The sealing material according to modification 3 is sealing material 602 according to embodiment 3. The step of piston 165 is composed of step-forming portions 165a, 165b, and 165c. As shown in Fig. 22 , piston 165 has step-forming portion 165b on the inner circumferential side, step-forming portion 165a in the center, and step-forming portion 165c on the outer circumferential side.

[0128] As shown in FIG. 21 , the piston 165 has a groove extending radially of the piston 165 at the upper end of a step-forming portion 165c, which is the outer peripheral portion of the piston 165. The radial groove provided in the step-forming portion 165c forms a step-forming portion 165d. As shown in FIG. 21 , the height of the step-forming portion 165d in the axial direction is lower than the height of the step-forming portion 165c. As shown in FIG. 22 , a plurality of step-forming portions 165d are provided at the end of the annular step-forming portion 165c. The plurality of step-forming portions 165d are spaced apart from one another in the circumferential direction of the piston 165 and are arranged at equal intervals.

[0129] The axial height of step-forming portion 165d is lower than the axial height of step-forming portion 165c. As shown in FIG. 21 , compared to embodiment 3, the side of the step of piston 165 further includes a side of the step on the side of step-forming portion 164d, which is a surface connecting the upper surface of step-forming portion 165a with the upper surface of step-forming portion 165d. Here, in modification 3, when sealing material 602 floats up, the outer peripheral side of sealing material-forming portion 602b contacts step-forming portion 165a, which is a T-shaped protrusion, and seals the gap. In other words, regardless of the axial height of step-forming portion 165d, fluid leakage through step-forming portion 165d does not occur.

[0130] In the piston 163 of the rotary compressor 400 according to the fourth embodiment, the piston 164 of the rotary compressor 410 according to the second modification, and the piston 165 of the rotary compressor 420 according to the third modification, radially extending grooves are provided at the ends of step-forming portions 163b, 164c, and 165c, which are on the outer peripheral side of the steps of the pistons 163, 164, and 165. In the pistons 163, 164, and 165, grooves are provided at intervals in the circumferential direction at the ends of the step-forming portions 163b, 164c, and 165c. These grooves form step-forming portions 163c, 164d, and 165d.

[0131] Steps are provided on pistons 163, 164, and 165, and sealing materials shaped to fit into the steps are provided to prevent the sealing materials from shifting position and suppress a decrease in sealing effectiveness. Here, grooves extending radially in pistons 163, 164, and 165 form flow paths perpendicular to the refrigerant leakage direction, which acts as a labyrinth seal and suppresses fluid leakage.

[0132] The configurations described in the above embodiments are merely examples of the contents of the present disclosure, and the techniques of the embodiments may be combined with each other or with other known techniques. Furthermore, it is also possible to omit or modify part of the configurations without departing from the gist of the present disclosure.

[0133] 100, 110, 200, 300, 400, 410, 420 Rotary compressor, 1 Sealed container, 10 Compression mechanism section, 11 Main shaft, 12 Eccentric shaft section, 13 Cylinder, 14 Upper bearing, 15 Lower bearing, 14a, 15a Flexible structure groove, 16, 161, 162, 163, 164, 165 Piston, 16a, 16b, 161a, 161b, 161c, 162a, 162b, 162c, 163a, 163b, 163c, 164a, 164b, 164c, 164d, 165a, 165b, 165c, 165d Step forming section, 17 Vane, 18 Discharge muffler, 19 Cavity section, 19a, 19b, 19c Branch passage, 20 electric motor section, 21 rotor, 22 stator, 30 cylinder chamber, 31 suction side space, 32 compression side space, 40 suction pipe, 41 suction port, 42 discharge pipe, 50 oil reservoir, 60, 601, 602 sealing material, 60a, 60b, 601a, 601b, 601c, 602a, 602b, 602c sealing material forming section, 70 intermediate plate, 71 intermediate plate hole, 121 first eccentric shaft section, 122 second eccentric shaft section, 131 first cylinder, 132 second cylinder, 301 first cylinder chamber, 302 second cylinder chamber.

Claims

1. A rotary compressor comprising: a drive shaft having an eccentric shaft portion; a cylinder whose both axial ends are closed by closing members; and a piston into which the eccentric shaft portion is inserted and which moves eccentrically within the cylinder, wherein the piston has a step at one end in the axial direction that varies in height in the axial direction, and a sealing material that covers the step is provided at the end.

2. A rotary compressor according to claim 1, characterized in that the sealing material has a shape having a portion on the inner circumferential side that is higher in the axial direction and a portion on the outer circumferential side that is lower in the axial direction.

3. A rotary compressor according to claim 2, characterized in that the lower part of the sealing material covers the part of the step of the piston that is closest to the closing member.

4. A rotary compressor according to any one of claims 1 to 3, characterized in that the outer diameter of the sealing material is the same as the outer diameter of the piston.

5. A rotary compressor according to any one of claims 1 to 4, characterized in that the sealing material has an L-shaped cross section in the radial direction.

6. A rotary compressor according to any one of claims 1 to 4, characterized in that the sealing material has a T-shaped cross section in the radial direction.

7. A rotary compressor according to any one of claims 1 to 4, characterized in that the sealing material has a U-shaped cross section in the radial direction.

8. A rotary compressor according to any one of claims 1 to 7, characterized in that the piston is provided with a groove extending in the radial direction at the outer peripheral end of the step.

9. A rotary compressor according to any one of claims 1 to 8, characterized in that grooves are provided at intervals in the circumferential direction on the outer peripheral end of the step of the piston.

Images