Rotary compressor and refrigeration device

Abstract

A rotary compressor according to the present invention includes: a casing (11); a cylinder (41, 42) that is disposed inside the casing; a piston (61, 62) that rotates eccentrically inside the cylinder; a shaft (81) that is connected to the piston and has a cavity (81a) therein; piping (85, 185, 285, 385) that is spaced apart from a wall of the cavity and disposed inside the cavity; an upper bearing (32) that is disposed at an upper part of the cylinder and supports the shaft; a lower bearing (31) that is disposed at a lower part of the cylinder and supports the shaft; a rear muffler (34) that is disposed at a lower part of the lower bearing; and a positive displacement pump (50) that is attached to the rear muffler and discharges oil into the piping.

Description

Rotary Compressor and Refrigeration Device

[0001] The present disclosure relates to a rotary compressor and a refrigeration device including the same. A rotary compressor is a compressor that compresses gas in a compression chamber formed in a cylinder by eccentrically rotating a roller in the cylinder. A rotary compressor generally has a vane for partitioning the compression chamber. The rotary compressor includes a so-called rolling piston type in which a vane separate from the roller contacts the roller while the roller rotates eccentrically, a so-called swing type in which a vane integrally formed with the roller swings as the roller rotates eccentrically, a so-called hinge vane type in which the tip of the vane is rotatably fitted in a recess on the outer peripheral surface of the roller and the roller rotates eccentrically, and the like.

[0002] Patent Document 1 discloses a rotary compressor including a casing, a cylinder disposed in the casing, a piston for forming a suction compression chamber in the cylinder, a shaft connected to the piston, and an upper bearing disposed above the cylinder and supporting the shaft. Patent Document 1 discloses that an oil reservoir space for storing oil is formed at the lower part of the casing of the rotary compressor, and an oil supply main path communicating with the oil reservoir space and through which the oil stored in the oil reservoir space flows upward is formed inside the shaft.

[0003] Japanese Patent Application Laid-Open No. 2015-197044

[0004] In a rotary compressor, it is desirable that the oil supply state does not change depending on the oil level in the lubricating oil and the rotational speed of the rotary compressor.

[0005] The present disclosure provides a rotary compressor having an oil supply structure in which the variation in the oil supply state is small even when the oil level in the lubricating oil and the rotational speed of the rotary compressor vary.

[0006] The rotary compressor in the first aspect comprises: a casing; a cylinder disposed inside the casing; a piston that rotates eccentrically inside the cylinder; a shaft connected to the piston and having a hollow interior; piping disposed inside the cavity, separated from the walls of the cavity; an upper bearing disposed above the cylinder and supporting the shaft; a lower bearing disposed below the cylinder and supporting the shaft; a rear muffler disposed below the lower bearing; and a positive displacement pump attached to the rear muffler and discharging oil into the piping.

[0007] According to the rotary compressor from the first perspective, the influence of the oil level in the lubricating oil and the rotational speed in the rotary compressor can be reduced.

[0008] The rotary compressor in the second view is the rotary compressor in the first view, with the lower part of the piping fixed to the shaft.

[0009] According to the rotary compressor from the second perspective, the piping can be integrally fixed to the shaft.

[0010] The rotary compressor in the third view is the rotary compressor described in the first or second view, wherein the upper part of the piping is fixed to the shaft.

[0011] According to the rotary compressor from a third perspective, the piping can be more securely fixed to the shaft.

[0012] The rotary compressor of the fourth viewpoint is a rotary compressor of any of the first to third viewpoints, wherein the piping has a hole at the top, and the hydraulic diameter of the hole is greater than or equal to the inner diameter of the piping.

[0013] According to the rotary compressor from the fourth perspective, lubricating oil can be supplied from the inside of the piping to the outside through holes without obstructing the flow of lubricating oil.

[0014] The rotary compressor of the fifth perspective is the rotary compressor of the fourth perspective, wherein the hole is located above the upper bearing lubrication hole provided on the shaft.

[0015] According to the rotary compressor from the fifth perspective, lubricating oil can be supplied stably to the upper bearing.

[0016] The rotary compressor of the sixth perspective is a rotary compressor of the second perspective in which the lower part of the piping is fixed to the shaft at a position offset vertically from the lower bearing.

[0017] According to the rotary compressor from the sixth perspective, deformation of the lower part of the piping can suppress deformation of the lower bearing.

[0018] The rotary compressor of the seventh perspective is the rotary compressor of the second perspective, wherein the piping has a flow path that penetrates vertically in the portion fixed to the shaft.

[0019] According to the rotary compressor from the seventh perspective, the lubricating oil that has passed through the piping and returned can be discharged.

[0020] The rotary compressor of the eighth perspective is the rotary compressor of the seventh perspective, wherein the total cross-sectional area of ​​the flow path is greater than or equal to the first cross-sectional area inside the piping and the second cross-sectional area between the inside of the shaft and the piping.

[0021] According to the rotary compressor from the eighth perspective, lubricating oil can be discharged more efficiently.

[0022] The rotary compressor of the ninth viewpoint is a rotary compressor of the second viewpoint in which the upper part of the piping is provided at a distance from the shaft.

[0023] According to the rotary compressor from the ninth perspective, the piping structure can be simplified.

[0024] The rotary compressor of the tenth perspective is a rotary compressor of the ninth perspective in which the upper part of the piping is located above the upper bearing lubrication hole provided on the shaft.

[0025] According to the rotary compressor in the tenth perspective, lubricating oil can be stably supplied to the upper bearing.

[0026] The rotary compressor of the eleventh aspect is a rotary compressor of the first aspect in which the hydraulic diameter in the first flow path between the inside of the shaft and the piping is smaller than the hydraulic diameter inside the piping.

[0027] According to the rotary compressor of the eleventh perspective, by suppressing the free fall of lubricating oil in the first flow path and filling the first flow path with lubricating oil, it is possible to prevent a shortage of lubricating oil.

[0028] The rotary compressor of the twelfth aspect is a rotary compressor of the first aspect in which the hydraulic diameter in the first flow path between the inside of the shaft and the piping is larger than the hydraulic diameter inside the piping.

[0029] According to the rotary compressor of the twelfth perspective, the flow velocity of the lubricating oil in the first flow path can be suppressed, allowing for efficient supply of lubricating oil.

[0030] The rotary compressor of the 13th perspective is the rotary compressor of the first perspective, wherein the upper end of the piping is located below the upper bearing lubrication hole provided in the shaft.

[0031] According to the rotary compressor from the 13th perspective, the length of the piping can be shortened.

[0032] The rotary compressor of the 14th viewpoint is the rotary compressor of the first viewpoint in which the rear muffler has a wall portion that protrudes downward, and the positive displacement pump is fixed to the wall portion.

[0033] According to the rotary compressor in the 14th perspective, the positive displacement pump can be stably fixed to the rear muffler.

[0034] The rotary compressor of the 15th viewpoint is the rotary compressor of the 14th viewpoint, wherein the rear muffler has an opening in the wall portion that communicates with the lower space in the casing.

[0035] According to the rotary compressor described in the 15th perspective, lubricating oil can be stably discharged into the lower space.

[0036] The rotary compressor in the 16th perspective is a rotary compressor in either the 1st or 15th perspective, wherein the positive displacement pump is a trochoid pump.

[0037] According to the rotary compressor described in the 16th perspective, lubricating oil can be supplied stably to the piping.

[0038] The refrigeration system of the first aspect is a refrigeration system equipped with a rotary compressor as described in any of the first or sixteenth aspects.

[0039] According to the refrigeration system of the first perspective, the influence of the oil level in the lubricating oil and the rotational speed in the rotary compressor can be reduced in a rotary compressor.

[0040] Figure 1 is a perspective view of a rotary compressor according to the first embodiment. Figure 2 is a cross-sectional view of a rotary compressor according to the first embodiment. Figure 3 is a cross-sectional view of a rotary compressor according to the first embodiment. Figure 4 is an exploded perspective view of a positive displacement pump in a rotary compressor according to the first embodiment. Figure 5 is a bottom view of the body of the positive displacement pump in a rotary compressor according to the first embodiment. Figure 6 is a plan view of the body of the positive displacement pump in a rotary compressor according to the first embodiment. Figure 7 is a perspective view illustrating the mounting of the positive displacement pump in a rotary compressor according to the first embodiment. Figure 8 is a plan view illustrating the operation of the positive displacement pump in a rotary compressor according to the first embodiment. Figure 9 is a cross-sectional view illustrating the flow of lubricating oil in a rotary compressor according to the first embodiment. Figure 10 is a cross-sectional view illustrating the flow of lubricating oil in a modified example of the rotary compressor according to the first embodiment. Figure 11 is a perspective view of the piping in a rotary compressor according to the first embodiment. Figure 12 is a cross-sectional view of a rotary compressor according to the second embodiment. Figure 13 is a cross-sectional view of a rotary compressor according to the third embodiment. Figure 14 is a cross-sectional view of a rotary compressor according to the fourth embodiment. Figure 15 is a perspective view of the piping in a rotary compressor according to the fourth embodiment. Figure 16 is a schematic diagram of a refrigeration system equipped with the rotary compressor according to this embodiment.

[0041] <First Embodiment> A specific example of the rotary compressor of the first embodiment will be described below with reference to the drawings. However, this disclosure is not limited to these examples and is intended to include all modifications within the meaning and scope of the equivalents of the claims, as indicated by the claims.

[0042] Regarding the descriptions in the specifications and drawings according to each embodiment, for components having substantially the same or corresponding functional configurations, the same reference numerals may be used to omit redundant explanations. Also, for ease of understanding, the scales of the respective parts in the drawings may be different from the actual ones.

[0043] Regarding directions such as parallel, right-angled, orthogonal, horizontal, vertical, up and down, left and right, and front and back, a deviation within a range that does not impair the effects of the embodiment is allowed. The shape of the corners is not limited to right-angles and may be rounded. For parallel, right-angled, orthogonal, horizontal, and vertical, each may include substantially parallel, substantially right-angled, substantially orthogonal, substantially horizontal, and substantially vertical.

[0044] For example, substantially parallel means that even if two lines or two surfaces are not completely parallel to each other, they can be treated as parallel to each other within an acceptable range in manufacturing. For each of the other substantially right-angled, substantially orthogonal, substantially horizontal, and substantially vertical, similar to substantially parallel, it is intended that they correspond respectively as long as the mutual positional relationship between two lines or two surfaces is within an acceptable range in manufacturing.

[0045] The rotary compressor according to the first embodiment will be described. The rotary compressor according to the first embodiment includes a casing, a cylinder disposed inside the casing, a piston that eccentrically rotates inside the cylinder, and a shaft that is connected to the piston and has a hollow interior. The piston is generally composed of a circular roller and a vane that partitions the compression chamber. Further, the rotary compressor according to the first embodiment includes a pipe disposed inside the hollow, separated from the wall of the hollow, an upper bearing disposed above the cylinder for supporting the shaft, and a lower bearing disposed below the cylinder for supporting the shaft. Furthermore, the rotary compressor according to the first embodiment includes a rear muffler disposed below the lower bearing, and a positive displacement pump attached to the rear muffler for discharging oil inside the pipe.

[0046] FIG. 1 is a perspective view of a rotary compressor 1 which is an example of the rotary compressor according to the first embodiment. FIGS. 2 and 3 are cross-sectional views of a rotary compressor 1 which is an example of the rotary compressor according to the first embodiment. FIG. 3 is an enlarged cross-sectional view of the compression part 70 in the rotary compressor 1.

[0047] Incidentally, in the drawings, for the sake of convenience of explanation, a virtual three-dimensional coordinate system (XYZ orthogonal coordinate system) composed of an X-axis, a Y-axis, and a Z-axis (XYZ axes) orthogonal to each other may be set. For example, regarding the coordinate axis perpendicular to the drawing paper surface, when a black dot is shown inside the circle of the coordinate axis, it represents that the coordinate axis is facing the front side with respect to the drawing paper surface. Further, when a cross mark is shown inside the circle of the coordinate axis, it represents that the coordinate axis is facing the back side with respect to the drawing paper surface.

[0048] However, the said coordinate system is defined for the purpose of explanation and does not limit the posture of the rotary compressor etc. according to the present embodiment.

[0049] Incidentally, in the following drawings, the shaft 81 of the rotary compressor 1 extends in the direction along the Z-axis, and in a plane parallel to the XY plane including the X-axis and the Y-axis, each of the pistons 61 and 62 of the rotary compressor 1 rotates.

[0050] A view of an object looking from the +Z side in the opposite direction of the Z-axis along the Z-axis direction is called a plan view. Looking at an object from the +Z side in the opposite direction of the Z-axis along the Z-axis direction is called a plan view. A view of an object looking from the -Z side in the direction of the Z-axis along the Z-axis direction is called a bottom view. Looking at an object from the -Z side in the direction of the Z-axis along the Z-axis direction is called a bottom view.

[0051] The rotary compressor 1 compresses a refrigerant. The refrigerant used in the rotary compressor 1 is, for example, carbon dioxide. Incidentally, the refrigerant is not limited to carbon dioxide, and may be, for example, a fluorocarbon-based, hydrofluoroolefin-based, or hydrocarbon-based refrigerant. The rotary compressor 1 includes a compressor main body 10 and an accumulator 20.

[0052] [Compressor Main Body 10] The compressor main body 10 includes a casing 11, an intake pipe 12, an exhaust pipe 13, and power terminals 15. Further, the casing 11 includes a plate 14 for installing the compressor main body 10.

[0053] The compressor body 10 comprises a compression unit 70 and an electric motor unit 80 inside the casing 11. The electric motor unit 80 rotates the shaft 81. The compression unit 70 compresses the refrigerant supplied from the intake pipe 12. The refrigerant compressed in the compression unit 70 is discharged to the outside of the rotary compressor 1 through the exhaust pipe 13. The compression unit 70 constitutes the compression mechanism.

[0054] The electric unit 80 rotates the shaft 81. The shaft 81 is connected to the piston 61 and the piston 62, respectively. In the compression unit 70, the shaft 81 rotated by the electric unit 80 rotates the piston 61 and the piston 62, respectively. The pistons 61 and 62 rotate eccentrically as the shaft 81 rotates. As the pistons 61 and 62 rotate, the refrigerant is compressed in the compression unit 70. Each of the pistons 61 and 62 is composed of a circular roller and a vane that partitions the compression chamber. The shaft 81 is a hollow shaft having an internal space 81a. The shaft 81 is a shaft with a hollow interior. The piping 85 is inserted into the internal space 81a. The piping 85 is positioned away from the inner wall that forms the internal space 81a of the shaft 81.

[0055] The shaft 81 has a main shaft portion 82, an eccentric portion 83, an intermediate connecting portion 84, an eccentric portion 86, and a sub-shaft portion 87. In the shaft 81, the main shaft portion 82, the eccentric portion 83, the intermediate connecting portion 84, the eccentric portion 86, and the sub-shaft portion 87 are formed integrally.

[0056] The main spindle portion 82 has a cylindrical or cylindrical shape. The upper end of the main spindle portion 82 is connected to the rotor of the motor in the electric unit 80. The lower end of the main spindle portion 82 is rotatably supported by the upper bearing 32. The lower end of the main spindle portion 82 forms a journal.

[0057] The eccentric portion 83 is a cylindrical part with a larger diameter than the main shaft portion 82. The central axis of the eccentric portion 83 is eccentric to the central axis of the main shaft portion 82. The piston 62 is attached to the eccentric portion 83.

[0058] The intermediate connecting section 84 connects the eccentric section 83 and the eccentric section 86.

[0059] The eccentric portion 86 is a cylindrical part with a larger diameter than the main shaft portion 82. The central axis of the eccentric portion 86 is eccentric from the central axis of the main shaft portion 82. The eccentric portion 86 is eccentric with respect to the central axis of the main shaft portion 82 on the opposite side from the eccentric portion 83. The piston 61 is attached to the eccentric portion 86. The lower surface of the eccentric portion 86 slides against the upper surface of the lower bearing 31.

[0060] The sub-shaft portion 87 has a cylindrical or cylindrical shape. The sub-shaft portion 87 is rotatably supported by the lower bearing 31. The sub-shaft portion 87 constitutes a journal.

[0061] The compression section 70 comprises a lower bearing 31, a cylinder 41, a middle plate 33, a cylinder 42, and an upper bearing 32. The lower bearing 31, cylinder 41, middle plate 33, cylinder 42, and upper bearing 32 are stacked in order from bottom to top. The upper bearing 32 is positioned above each of the cylinders 41 and 42. The lower bearing 31 is positioned below each of the cylinders 41 and 42. A shaft 81 passes through each of the lower bearing 31, cylinder 41, middle plate 33, cylinder 42, and upper bearing 32. Each of the lower bearing 31, cylinder 41, middle plate 33, cylinder 42, and upper bearing 32 is provided with an oil supply hole through which the shaft 81 passes, for supplying lubricating oil. The shaft 81 also has a communication hole that penetrates from the internal space 81a to the outside of the shaft 81 in order to supply lubricating oil to each of the lower bearing 31, cylinder 41, cylinder 42, and upper bearing 32. Specifically, the shaft 81 has a lower bearing oil supply hole 81h1, a communication hole 81h2, a communication hole 81h3, and an upper bearing oil supply hole 81h4, respectively, for supplying lubricating oil to the lower bearing 31, cylinder 41, cylinder 42, and upper bearing 32. The shaft 81 may also have a communication hole for supplying lubricating oil to the middle plate 33.

[0062] The compression section 70 includes a piston 61 inside the cylinder 41 that rotates eccentrically by a shaft 81. The lower surface of the piston 61 slides against the upper surface of the lower bearing 31. The upper surface of the piston 61 also slides against the lower surface of the middle plate 33.

[0063] Furthermore, the compression section 70 includes a piston 62 inside the cylinder 42 that rotates eccentrically by a shaft 81. The lower surface of the piston 62 slides against the upper surface of the middle plate 33. The upper surface of the piston 62 also slides against the lower surface of the upper bearing 32.

[0064] Furthermore, the compression unit 70 includes a rear muffler 34 positioned below the lower bearing 31. In addition, the compression unit 70 includes a positive displacement pump 50 attached to the rear muffler 34.

[0065] (Positive displacement pump 50) The positive displacement pump 50 will be described in detail. Figure 4 is an exploded perspective view of the positive displacement pump 50 in a rotary compressor 1, which is an example of a rotary compressor according to the first embodiment.

[0066] The positive displacement pump 50 discharges lubricating oil into the internal space 81a of the shaft 81. More specifically, the positive displacement pump 50 discharges lubricating oil into the piping 85. The positive displacement pump 50 is a trochoid pump. In the rotary compressor according to the first embodiment, the positive displacement pump is not limited to a trochoid pump, but may be, for example, a gear pump, a vane pump, or a piston pump.

[0067] The positive displacement pump 50 is attached to the rear muffler 34. The positive displacement pump 50 comprises a main body 51, an outer rotor 52, an inner rotor 53, and a thrust plate 54.

[0068] (Main body 51) The main body 51 will be described in detail. Figure 5 is a bottom view of the main body 51 of the positive displacement pump 50 in a rotary compressor 1, which is an example of a rotary compressor according to the first embodiment. Figure 6 is a top view of the main body 51 of the positive displacement pump 50 in a rotary compressor 1, which is an example of a rotary compressor according to the first embodiment.

[0069] The main body 51 has a recess 51g at its upper part in which the outer rotor 52 and inner rotor 53 are housed. The main body 51 also has a through hole 51s that penetrates from the bottom surface 51D, which is the lowest surface, to the bottom surface 51S of the recess 51g. The positive displacement pump 50 sucks the lubricating oil accumulated in the oil reservoir SP (lower space) through the through hole 51s.

[0070] A groove 51d is formed on the bottom surface 51S of the recess 51g of the main body 51.

[0071] The main body 51 has a plurality of flange portions 51f extending in a direction parallel to the XY plane at its upper end. Each of the plurality of flange portions 51f has a through hole 51h through which a bolt 55 passes. An outer surface 51T, which is part of a cylindrical surface, is formed in the portion where the flange portion 51f is formed.

[0072] (Outer rotor 52) The outer rotor 52 is fixed to the recess 51g in the main body 51. The outer rotor 52 has a through hole 52h in the center into which the inner rotor 53 is inserted. The inner surface 52S of the through hole 52h has a cross-sectional shape that is a trochoid curve.

[0073] (Inner rotor 53) The inner rotor 53 is inserted into the through hole 52h of the outer rotor 52. The inner rotor 53 is rotatable inside the through hole 52h of the outer rotor 52. The outer surface 53S of the inner rotor 53 has a cross-sectional shape that is a trochoid curve. The number of teeth on the inner rotor 53 is one less than the number of teeth on the outer rotor 52. The inner rotor 53 has a through hole 53h in the center.

[0074] (Thrust plate 54) The thrust plate 54 is a plate for holding down the inner rotor 53. The thrust plate 54 has a through hole 54h in the center.

[0075] The attachment of the positive displacement pump 50 to the rear muffler 34 will now be described. Figure 7 is a perspective view illustrating the attachment of the positive displacement pump 50 in a rotary compressor 1, which is an example of a rotary compressor according to the first embodiment.

[0076] The rear muffler 34 comprises a flat plate portion 34a extending in the X-axis and Y-axis directions, and a wall portion 34b extending from the flat plate portion 34a in the opposite direction to the Z-axis along the Y-axis direction (vertical direction). The wall portion 34b has an inner surface 34S. The wall portion 34b protrudes downward from the flat plate portion 34a.

[0077] The positive displacement pump 50 is fitted into the wall portion 34b. Specifically, the positive displacement pump 50 is fitted into the wall portion 34b by fitting the outer surface 51T of the main body 51 of the positive displacement pump 50 with the inner surface 34S of the wall portion 34b. The positive displacement pump 50 may also be fitted into the rear muffler 34 by press-fitting.

[0078] The wall portion 34b has a threaded hole 34s into which a bolt 55 is inserted. The bolt 55 passes through the through hole 51h in the flange portion 51f and is screwed into the threaded hole 34s in the wall portion 34b. By screwing the bolt 55 into the threaded hole 34s, the flange portion 51f is fixed to the wall portion 34b by the bolt 55. By fixing the flange portion 51f to the wall portion 34b by the bolt 55, the positive displacement pump 50 is fixed to the rear muffler 34.

[0079] Furthermore, a gap is formed in the portion where the inner surface 34S and the outer surface 51T of the wall portion 34b are not in contact. Lubricating oil discharged into the internal space 81a of the shaft 81 is discharged into the oil reservoir SP through this gap.

[0080] Next, the operation of the positive displacement pump 50 will be described. Figure 8 is a plan view illustrating the operation of the positive displacement pump 50 in a rotary compressor 1, which is an example of a rotary compressor according to the first embodiment. More specifically, Figure 8 is a plan view showing a top view of the outer rotor 52 and inner rotor 53 in the positive displacement pump 50. When the inner rotor 53 rotates relative to the outer rotor 52 in the direction of the arrowed line R, lubricating oil accumulated in the oil reservoir SP is sucked in range DS. A through hole 51s is connected to range DS. Then, the lubricating oil is discharged in range DE. The lubricating oil is discharged downwards once, then passes through the groove 51d and through the through hole 53h of the inner rotor 53 before being discharged.

[0081] As described above, as the inner rotor 53 rotates relative to the outer rotor 52, lubricating oil is drawn in through the through hole 51s of the main body 51. The drawn-in lubricating oil is then transported as the outer rotor 52 rotates. The transported lubricating oil is then discharged through the through hole 53h of the inner rotor 53 into the internal space 81a of the shaft 81.

[0082] The flow of lubricating oil will be explained in detail. Figure 9 is a cross-sectional view illustrating the flow of lubricating oil in a rotary compressor 1, which is an example of a rotary compressor according to the first embodiment. The lubricating oil accumulated in the oil reservoir SP is sucked in through the through hole 51s, as shown by the dotted line SC with an arrow. The sucked-in lubricating oil is transferred by the rotation of the inner rotor 53 relative to the outer rotor 52. The transferred lubricating oil is then discharged into the interior of the piping 85 through the groove 51d, as shown by the dotted line DC with an arrow, and then discharged into the internal space 81a of the shaft 81.

[0083] The lubricating oil discharged into the piping 85 of the shaft 81 passes through the inside of the piping 85 and is supplied between the internal space 81a and the piping 85, as shown by the dotted line with arrow in Figure 3. The lubricating oil supplied between the internal space 81a and the piping 85 is supplied to the lower bearing 31, cylinder 41, cylinder 42, and upper bearing 32 from the lower bearing oil supply hole 81h1, communication hole 81h2, communication hole 81h3, and upper bearing oil supply hole 81h4, respectively.

[0084] Furthermore, any lubricating oil supplied between the internal space 81a and the piping 85 that is not supplied to the lower bearing 31, cylinder 41, cylinder 42, and upper bearing 32 is discharged from the internal space 81a of the shaft 81. More specifically, the lubricating fluid is discharged from the flow path (first flow path) between the internal space 81a and the piping 85. The lubricating oil discharged from the internal space 81a of the shaft 81 is discharged into the oil reservoir SP through the gap between the rear muffler 34 and the positive displacement pump 50, along the dotted line DR with an arrow shown in Figure 9.

[0085] The method for discharging the lubricating oil discharged from the internal space 81a of the shaft 81 into the oil reservoir SP is not limited to the above example. Figure 10 is a cross-sectional view illustrating the flow of lubricating oil in a modified rotary compressor 1, which is an example of a rotary compressor according to the first embodiment. In this modified example, a rear muffler 134 is provided instead of a rear muffler 34. The rear muffler 134 has an opening 134h in its wall portion 134b that communicates with the outside of the wall portion 134b in order to discharge the lubricating oil into the oil reservoir SP. As shown by the dotted line DR with an arrow in Figure 10, the lubricating oil may be discharged into the oil reservoir SP through the opening 134h.

[0086] Furthermore, if the rear muffler has an opening, it is not necessary to provide a gap between the rear muffler and the positive displacement pump, as is the case with the rotary compressor 1.

[0087] Furthermore, as shown in Figures 9 and 10, the lower end 81e of the shaft 81 may be positioned at a distance from the thrust plate 54. The distance h is between the lower end 81e of the shaft 81 and the thrust plate 54.

[0088] The lower part of the piping 85 may be fixed to the inner rotor 53 in order to rotate the inner rotor 53. Alternatively, the lower part of the shaft 81 may be fixed to the inner rotor 53 in order to rotate the inner rotor 53.

[0089] The piping 85 will now be described. Figure 11 is a perspective view of the piping 85 in a rotary compressor 1, which is an example of a rotary compressor according to the first embodiment. The piping 85 comprises a pipe 85p and a flange portion 85f.

[0090] The pipe 85p is positioned in the internal space 81a of the shaft 81, separated from the walls (cavity walls) that form the internal space 81a. The upper part of the pipe 85p is inserted into and fixed in a hole provided in the shaft 81. The flange portion 85f is provided at the lower part of the piping 85. The lower part of the pipe 85p is fixed to the inner wall of the flange portion 85f by press-fitting. The lower end of the pipe 85p may have a gap between it and a step in the inner wall, or it may abut against a step in the inner wall. The flange portion 85f is fixed to the shaft 81. In other words, the piping 85 has a double-supported structure on the shaft 81. As a result, the piping 85 is firmly fixed and the effects of vibration can be suppressed. The flange portion 85f is fixed to the shaft 81 at a position offset vertically from the lower bearing 31. As a result, deformation of the bearing portion in the lower bearing 31 can be suppressed when fixing the positive displacement pump 50 by fitting or press-fitting.

[0091] The pipe 85p has a hole 85ph. The hole 85ph is located above the oil supply hole (upper bearing oil supply hole 81h4) provided in the upper bearing 32. By having the hole 85ph located above the oil supply hole (upper bearing oil supply hole 81h4) provided in the upper bearing 32, oil can be supplied to the upper bearing 32. The hydraulic diameter of the hole 85ph may be greater than or equal to the inner diameter of the pipe 85p. By having the hydraulic diameter of the hole 85ph greater than or equal to the inner diameter of the pipe 85p, it is possible to suppress obstruction of the flow of lubricating oil through the pipe 85p by the hole 85ph.

[0092] The number of holes 85ph is not limited to one; multiple holes may be provided. If multiple holes 85ph are provided, the hydraulic diameter mentioned above shall be the sum of the diameters of each of the multiple holes 85ph.

[0093] Furthermore, the hydraulic diameter in the flow path (first flow path) between the internal space 81a of the shaft 81 and the pipe 85p may be smaller than the hydraulic diameter inside the pipe 85p. By making the hydraulic diameter in the first flow path smaller than the hydraulic diameter inside the pipe 85p, the flow of lubricating oil in the first flow path is suppressed, thereby preventing insufficient lubrication due to free fall of lubricating oil and ensuring reliable lubrication.

[0094] The hydraulic diameter in the flow path (first flow path) between the internal space 81a of the shaft 81 and the pipe 85p may be larger than the hydraulic diameter inside the pipe 85p. By making the hydraulic diameter in the first flow path larger than the hydraulic diameter inside the pipe 85p, the flow velocity inside the pipe in the first flow path is reduced, thereby enabling efficient oil supply to each oil supply hole.

[0095] The pipe 85p has a hole 85ph. The hydraulic diameter of the hole 85ph may be greater than or equal to the inner diameter of the pipe 85p. By having a hydraulic diameter of the hole 85ph greater than or equal to the inner diameter of the pipe 85p, it is possible to suppress obstruction of the flow of lubricating oil through the pipe 85p by the hole 85ph.

[0096] The flange portion 85f is provided with a notch portion 85fh that forms an up-and-down through-flow channel through which lubricating oil flows when the pipe 85 is fixed to the lower part of the shaft 81. The lubricating oil returns to the positive displacement pump 50 through the notch portion 85fh. The total cross-sectional area of ​​the flow channel formed by the notch portion 85fh is greater than or equal to the cross-sectional area inside the pipe 85p (first cross-sectional area) and the cross-sectional area between the inside of the shaft 81 and the pipe 85p (second cross-sectional area). By making the total cross-sectional area of ​​the flow channel formed by the notch portion 85fh greater than or equal to the first and second cross-sectional areas, the discharge of lubricating oil can be promoted.

[0097] The rotary compressor according to the first embodiment is equipped with a positive displacement pump, which allows for lubrication without being limited by the oil level in the lubricating oil or the rotational speed of the rotary compressor.

[0098] <Second Embodiment> A rotary compressor according to the second embodiment will now be described. The rotary compressor according to the second embodiment differs from the rotary compressor according to the first embodiment in its piping. The rotary compressor according to the second embodiment has a cantilevered piping structure.

[0099] Figure 12 is a cross-sectional view of a rotary compressor according to the second embodiment. In the rotary compressor according to the second embodiment, piping 185 is provided in place of piping 85 in the rotary compressor 1. Piping 185 comprises a pipe 185p and a flange portion 185f. The pipe 185p is positioned in the internal space 81a, separated from the wall (cavity wall) that forms the internal space 81a of the shaft 81. The upper part of the pipe 185p is provided separated from the shaft 81. The flange portion 185f is provided at the lower part of the pipe 185. The flange portion 185f is fixed to the shaft 81. That is, the pipe 185 has a cantilever structure on the shaft 81. As shown in Figure 12, the upper part of the pipe 185 does not have to be fixed to the shaft 81. In other words, the upper part of the pipe 185 may be provided separated from the shaft 81. Furthermore, the upper end of the piping 185 is located above the oil supply hole (upper bearing oil supply hole 81h4) provided in the upper bearing 32.

[0100] The rotary compressor according to the second embodiment has the same effects as the rotary compressor according to the first embodiment. Furthermore, since the rotary compressor according to the second embodiment does not fix the upper part of the piping, manufacturing costs can be reduced.

[0101] <Third Embodiment> A rotary compressor according to the third embodiment will now be described. The rotary compressor according to the third embodiment differs from the rotary compressor according to the first embodiment in its piping. The rotary compressor according to the third embodiment has a cantilevered piping structure.

[0102] Figure 13 is a cross-sectional view of a rotary compressor according to the third embodiment. In the rotary compressor according to the third embodiment, piping 285 is provided in place of piping 85 in the rotary compressor 1. Piping 285 comprises a pipe 285p and a flange portion 285f. Pipe 285p is positioned in the internal space 81a, separated from the wall (cavity wall) forming the internal space 81a of the shaft 81. The upper part of pipe 285p is provided separated from the shaft 81. The flange portion 285f is provided at the lower part of pipe 285. The flange portion 285f is fixed to the shaft 81. That is, pipe 285 has a cantilever structure on the shaft 81. Pipe 285 is even shorter than pipe 185. Lubricating oil can be supplied by spraying it from pipe 285.

[0103] The rotary compressor according to the third embodiment has the same effects as the rotary compressor according to the second embodiment. Furthermore, because the rotary compressor according to the third embodiment has a shorter piping length, the effects of vibration can be suppressed.

[0104] <Fourth Embodiment> A rotary compressor according to the fourth embodiment will now be described. The rotary compressor according to the fourth embodiment differs from the rotary compressor according to the first embodiment in its piping. In the rotary compressor according to the fourth embodiment, the upper part of the piping in the rotary compressor according to the second embodiment is fixed by an elastic member.

[0105] Figure 14 is a cross-sectional view of a rotary compressor according to the fourth embodiment. Figure 15 is a perspective view of a pipe 385, which is an example of piping in the rotary compressor according to the fourth embodiment. The pipe 385 comprises a pipe 385p, a flange portion 385f, and an elastic member 386. The pipe 385p has a hole 385ph. The flange portion 385f has a notch portion 385fh that becomes a vertically penetrating passage for lubricating oil when the pipe 385 is fixed to the lower part of the shaft 81. In the rotary compressor according to the fourth embodiment, the pipe 385 is provided in place of the pipe 85 in the rotary compressor 1. As shown in Figure 14, the upper part of the pipe 385 is fixed to the shaft 81 by the elastic member 386. The hole 385ph in the pipe 385 is located above the oil supply hole (upper bearing oil supply hole 81h4) provided in the upper bearing 32.

[0106] The rotary compressor according to the fourth embodiment has the same effects as the rotary compressor according to the second embodiment. Furthermore, since the upper part of the piping of the rotary compressor according to the fourth embodiment is fixed by an elastic member, the effects of vibration can be suppressed.

[0107] <Refrigeration System> A refrigeration system equipped with a rotary compressor according to this embodiment will be described. Figure 16 is a schematic diagram of a refrigeration system 100, which is an example of a refrigeration system equipped with a rotary compressor according to this embodiment.

[0108] The refrigeration system 100 includes a compressor 101, a four-way valve 102, a heat exchanger 103, an expansion valve 104, and a heat exchanger 105. The compressor 101 is a rotary compressor according to this embodiment.

[0109] First, we will explain the case where the refrigeration system 100 is cooled by the heat exchanger 105. Figure 15 shows the connections when the refrigeration system 100 is cooled by the heat exchanger 105.

[0110] The refrigerant compressed by the compressor 101 is supplied to the heat exchanger 103 through the four-way valve 102. In the heat exchanger 103, the refrigerant supplied to the heat exchanger 103 is cooled by heat exchange with air or the like. The refrigerant cooled in the heat exchanger 103 condenses and liquefies, and is supplied to the expansion valve 104. The refrigerant is depressurized by the expansion valve 104. The depressurized refrigerant is supplied to the heat exchanger 105. In the heat exchanger 105, the refrigerant evaporates and vaporizes. The refrigerant discharged from the heat exchanger 105 then returns to the compressor 101 and is compressed again. In the heat exchanger 105, the refrigeration device 100 cools the object by the heat of vaporization caused by the evaporation of the refrigerant.

[0111] Next, we will explain the case where the refrigeration system 100 is heated by the heat exchanger 105. The refrigerant compressed by the compressor 101 is supplied to the heat exchanger 105 through the four-way valve 102. In the heat exchanger 105, the refrigeration system 100 heats the object by supplying the compressed, high-temperature refrigerant. The refrigerant that has undergone heat exchange in the heat exchanger 105 condenses and liquefies, and is supplied to the expansion valve 104. The refrigerant is depressurized by the expansion valve 104. The depressurized refrigerant is supplied to the heat exchanger 103. In the heat exchanger 103, the refrigerant evaporates and vaporizes by exchanging heat with air or the like. The refrigerant discharged from the heat exchanger 103 then passes through the four-way valve 102 and returns to the compressor 101 to be compressed again.

[0112] While embodiments have been described above, it will be understood that various modifications to the form and details are possible without departing from the spirit and scope of the claims. Various modifications and improvements are possible, such as combinations or substitutions with some or all of other embodiments.

[0113] This application claims priority to Basic Patent Application No. 2024-162420, filed with the Japan Patent Office on September 19, 2024, the entire contents of which are incorporated herein by reference.

[0114] 1 Rotary compressor 10 Compressor body 11 Casing 31 Lower bearing 32 Upper bearing 34 Rear muffler 41, 42 Cylinder 50 Positive displacement pump 52 Outer rotor 53 Inner rotor 54 Thrust plate 61, 62 Piston 70 Compression section 80 Electric section 81 Shaft 81a Internal space 85 Piping 100 Refrigeration system 101 Compressor 103, 105 Heat exchanger 104 Expansion valve

Claims

1. A casing (11), cylinders (41, 42) disposed inside the casing (11), pistons (61, 62) that rotate eccentrically inside the cylinders (41, 42), a shaft (81) connected to the pistons (61, 62) and having a hollow interior (81a), piping (85, 185, 285, 385) disposed inside the hollow (81a) at a distance from the wall of the hollow (81a), an upper bearing (32) disposed above the cylinders (41, 42) and supporting the shaft (81), a lower bearing (31) disposed below the cylinders (41, 42) and supporting the shaft (81), and a rear muffler (34) disposed below the lower bearing (31). A rotary compressor (1) is provided with a positive displacement pump (50) attached to the rear muffler (34) and which discharges oil into the piping (85, 185, 285, 385).

2. The lower part of the piping (85, 185, 285, 385) is fixed to the shaft (81), the rotary compressor (1) according to claim 1.

3. The upper part of the piping (85, 385) is fixed to the shaft (81), the rotary compressor (1) according to claim 1 or claim 2.

4. The rotary compressor (1) according to any one of claims 1 to 3, wherein the pipe (85) has a hole (85ph) at its upper part, and the hydraulic diameter of the hole (85ph) is greater than or equal to the inner diameter of the pipe (85).

5. The rotary compressor (1) according to claim 4, wherein the hole (85ph) is located above the upper bearing lubrication hole (81h4) provided in the shaft (81).

6. The rotary compressor (1) according to claim 2, wherein the lower parts of the piping (85, 185, 285, 385) are fixed to the shaft (81) at a position offset in the vertical direction from the lower bearing (31).

7. The rotary compressor (1) according to claim 2, wherein the piping (85, 185, 285, 385) has vertically penetrating passages (85fh, 385fh) in the portion fixed to the shaft (81).

8. The rotary compressor (1) according to claim 7, wherein the total cross-sectional area of ​​the flow path is greater than or equal to the first inner cross-sectional area of ​​the piping (85, 185, 285, 385) and the second cross-sectional area between the inside of the shaft (81) and the piping (85, 185, 285, 385).

9. The rotary compressor (1) according to claim 2, wherein the upper parts of the piping (185, 285, 385) are provided at a distance from the shaft (81).

10. The rotary compressor (1) according to claim 9, wherein the upper part of the piping (85, 185, 385) is located above the upper bearing lubrication hole (81h4) provided in the shaft (81).

11. The rotary compressor (1) according to claim 1, wherein the hydraulic diameter in the first flow path between the inside of the shaft (81) and the pipes (85, 185, 385) is smaller than the hydraulic diameter inside the pipes (85, 185, 385).

12. The rotary compressor (1) according to claim 1, wherein the hydraulic diameter in the first flow path between the inside of the shaft (81) and the piping (85, 185, 385) is greater than the hydraulic diameter inside the piping (85, 185, 385).

13. The rotary compressor (1) according to claim 1, wherein the upper end of the piping (285) is located below the upper bearing lubrication hole (81h4) provided in the shaft (81).

14. The rotary compressor (1) according to claim 1, wherein the rear muffler (34, 134) is provided with downwardly protruding wall portions (34b, 134b), and the positive displacement pump (50) is fixed to the wall portions (34b, 134b).

15. The rotary compressor (1) according to claim 14, wherein the rear muffler (134) has an opening (134h) in the wall portion (134b) that communicates with the lower space (SP) in the casing (11).

16. The rotary compressor (1) according to any one of claims 1 to 15, wherein the positive displacement pump (50) is a trochoid pump.

17. A refrigeration system (100) comprising a rotary compressor (1) according to any one of claims 1 to 16.

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