Rotary compressor and refrigeration system

Abstract

This disclosure provides a rotary compressor that reduces input power relative to refrigeration capacity. [Solution] A rotary compressor comprising: a drive shaft that rotates around a first axis along a first direction and has an eccentric portion; a cylinder having an inner circumferential surface and forming a cylinder chamber partitioned by the inner circumferential surface of the cylinder; an eccentrically rotating cylindrical roller; and a blade that partitions the cylinder chamber into an intake side space and a discharge side space, wherein the roller has an inner circumferential surface which is a cylindrical surface centered on a second axis and an outer circumferential surface, the outer circumferential surface of the roller has a first side surface which includes a portion facing the intake hole on the intake side of the blade and a second side surface which is other than the first side surface, the second side surface which is shaped along a virtual cylindrical surface centered on a second axis, the first side surface which is shaped indented toward the second axis from the virtual cylindrical surface, and has a first end in the forward direction of rotation and a second end in the rear direction of rotation, and when the second end is closest to the inner circumferential surface of the cylinder, the second end is located behind the intake hole in the direction of rotation.

Description

Technical Field

[0001] The present disclosure relates to a rotary compressor and a refrigeration apparatus including the same. The rotary compressor compresses the gas in a compression chamber formed in a cylinder by eccentrically rotating a roller in the cylinder. The rotary compressor generally has blades for partitioning the compression chamber.

Background Art

[0002] Patent Document 1 discloses a swing-type rotary compressor in which a blade portion that partitions a cylinder chamber into a compression chamber and a suction chamber in which a suction hole opens is integrally projected on a piston, and the blade portion is swingably supported by a support body that is rotatably disposed on the cylinder. Patent Document 1 discloses that on the outer peripheral surface of the piston, on the suction chamber side with respect to the protruding position of the blade portion, a notch portion is formed that extends forward in the公转 direction from near the protruding position of the blade portion and displaces the suction closing position of the suction gas sucked from the suction hole to the compression chamber side.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a rotary compressor, it is required to improve the coefficient of performance (COP). The coefficient of performance is obtained by dividing the refrigerating capacity by the input of the compressor. In order to improve the coefficient of performance, for example, it is conceivable to reduce the input of the refrigerator.

[0005] The present disclosure provides a rotary compressor that reduces the input with respect to the refrigerating capacity.

Means for Solving the Problems

[0006] The rotary compressor from the first perspective is, A drive shaft that rotates around a first axis aligned with a first direction and has an eccentric portion, A cylinder having an inner circumferential surface, and a cylinder chamber formed by the inner circumferential surface of the cylinder, A cylindrical roller that rotates eccentrically in the cylinder chamber, A blade that divides the cylinder chamber into an intake side space and a discharge side space, Equipped with, The roller is fixed to the eccentric portion and has an inner circumferential surface which is a cylindrical surface centered on the second axis, and an outer circumferential surface which is an outer circumferential surface of the roller. The outer surface of the roller has a first side surface including the portion facing the intake hole on the intake side of the blade, and a second side surface other than the first side surface. The second side surface has a shape that follows a virtual cylindrical surface centered on the second axis. The first side surface has a shape that is recessed toward the second axis from the virtual cylindrical surface, and has a first end facing forward in the direction of rotation and a second end facing backward in the direction of rotation. When the second end is closest to the inner circumferential surface of the cylinder, the second end is positioned behind the intake hole in the direction of rotation.

[0007] According to the rotary compressor of the first perspective, the input can be reduced relative to the refrigeration capacity. By reducing the input relative to the refrigeration capacity, the rotary compressor of the first perspective can improve the coefficient of performance (COP).

[0008] The rotary compressor of the second viewpoint is the rotary compressor of the first viewpoint, wherein the first viewpoint is composed of one or more planes.

[0009] According to the second perspective of the rotary compressor, the input can be reduced more relative to the refrigeration capacity.

[0010] A rotary compressor according to the third view is a rotary compressor according to the first or second view, wherein the first end is formed at the connection portion between the roller and the blade.

[0011] According to the rotary compressor from a third perspective, the range over which torque is generated can be widened, allowing for a greater reduction in input relative to the refrigeration capacity.

[0012] The rotary compressor of the fourth perspective is a rotary compressor of any of the first to third perspectives, in which the angle between the straight line connecting the center of the roller and the second end and the center line of the blade is 43° or more and 145° or less.

[0013] According to the rotary compressor from the fourth perspective, the input can be reduced relative to the cooling capacity compared to a piston without piston cuts.

[0014] The rotary compressor of the fifth aspect is a rotary compressor of any of the first to fourth aspects, wherein the first side surface has a shape such that, at the bottom dead center, the refrigerant jet from the intake hole generates torque that rotates the roller along the rotational direction.

[0015] According to the fifth perspective of the rotary compressor, torque is generated in the rotational direction at the bottom dead center, which reduces the input relative to the cooling capacity.

[0016] The refrigeration system of the first aspect is a refrigeration system equipped with a rotary compressor as described in any of the first to fifth aspects.

[0017] According to the first aspect of the refrigeration system, the input can be reduced relative to the refrigeration capacity in a rotary compressor. [Brief explanation of the drawing]

[0018] [Figure 1] Figure 1 is a cross-sectional view of a rotary compressor according to the first embodiment. [Figure 2] Figure 2 is a cross-sectional view of the area near the cylinder in a rotary compressor according to the first embodiment. [Figure 3] Figure 3 is a cross-sectional view of the piston in a rotary compressor according to the second embodiment. [Figure 4]FIG. 4 is a cross-sectional view of a piston in the rotary compressor according to the third embodiment. [Figure 5] FIG. 5 is a cross-sectional view of a piston in the rotary compressor according to the fourth embodiment. [Figure 6] FIG. 6 is a cross-sectional view of a piston in the rotary compressor according to the fifth embodiment. [Figure 7] FIG. 7 is a diagram for explaining the relationship between the piston cut angle and the refrigerating capacity of the rotary compressor according to the present embodiment. [Figure 8] FIG. 8 is a diagram for explaining the relationship between the piston cut angle and the input of the rotary compressor according to the present embodiment. [Figure 9] FIG. 9 is a diagram for explaining the relationship between the piston cut angle and the coefficient of performance of the rotary compressor according to the present embodiment. [Figure 10] FIG. 10 is a diagram showing an outline of a refrigerating apparatus including the rotary compressor according to the present embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION

[0019] <First Embodiment> A specific example of the rotary compressor according to the first embodiment will be described below with reference to the drawings. It should be noted that the present disclosure is not limited to these examples, and is intended to be defined by the claims and to include all modifications within the meaning and scope equivalent to the claims.

[0020] Regarding the descriptions in the specifications and drawings according to each embodiment, components having substantially the same or corresponding functional configurations may be denoted by the same reference numerals, and redundant descriptions may be omitted. Also, for ease of understanding, the scales of each part in the drawings may be different from the actual ones.

[0021] A degree of deviation is permissible in directions such as parallel, right angles, orthogonal, horizontal, vertical, up and down, left and right, and front and back, as long as it does not impair the effects of the embodiment. The shape of the corners is not limited to right angles and may be rounded. Parallel, right angles, orthogonal, horizontal, and vertical may include approximately parallel, approximately right angles, approximately orthogonal, approximately horizontal, and approximately vertical, respectively.

[0022] For example, "approximately parallel" means that two lines or two planes can be treated as parallel to each other within a manufacturingly acceptable range, even if they are not perfectly parallel. Similarly, "approximately right angle," "approximately perpendicular," "approximately horizontal," and "approximately vertical" are intended to apply as long as the relative positions of the two lines or two planes are within a manufacturingly acceptable range.

[0023] A rotary compressor according to the first embodiment will now be described. The rotary compressor according to the first embodiment includes a drive shaft that rotates about a first axis along a first direction and has an eccentric portion, and a cylinder that has an inner circumferential surface and forms a cylinder chamber partitioned by the inner circumferential surface of the cylinder. The rotary compressor according to the first embodiment also includes a cylindrical roller that rotates eccentrically in the cylinder chamber, and a blade that partitions the cylinder chamber into an intake side space and a discharge side space. The roller in the rotary compressor according to the first embodiment has an inner circumferential surface that is a cylindrical surface centered on a second axis and fixed to the eccentric portion, and an outer circumferential surface of the roller. The outer circumferential surface of the roller in the rotary compressor according to the first embodiment has a first side surface that includes a portion facing the intake hole on the intake side of the blade, and a second side surface other than the first side surface. Furthermore, the second side surface of the roller in the rotary compressor according to the first embodiment has a shape along a virtual cylindrical surface centered on a second axis. Furthermore, the first side surface of the roller in the rotary compressor according to the first embodiment has a shape that is recessed toward the second axis from the virtual cylindrical surface, and has a first end facing forward in the direction of rotation and a second end facing backward in the direction of rotation. Also, in the rotary compressor according to the first embodiment, when the second end of the roller is closest to the inner circumferential surface of the cylinder, the second end is located behind the intake hole in the direction of rotation.

[0024] Furthermore, in the rotary compressor according to the first embodiment, the first side surface is formed by a single plane.

[0025] Figure 1 is a cross-sectional view of a rotary compressor 1, which is an example of a rotary compressor according to the first embodiment. Figure 2 is a cross-sectional view of the area near the cylinder in the rotary compressor 1, which is an example of a rotary compressor according to the first embodiment. Figure 2 shows cross-sections of cylinder 30 and cylinder 35. In Figure 2, the reference numerals in parentheses indicate elements in cylinder 35.

[0026] The rotary compressor 1 is a fully enclosed rotary compressor. The rotary compressor 1 is installed, for example, in a refrigerant circuit that performs a vapor compression type refrigeration cycle. The rotary compressor 1, for example, sucks in and compresses the refrigerant evaporated in an evaporator. The rotary compressor according to this embodiment is a rotary compressor of the type in which blades rotate eccentrically with the blades connected to specific positions on the outer circumference of the roller. The blades are sometimes called vanes. The rotary compressor according to this embodiment may be a so-called swing type in which the vanes and rollers are formed integrally, or it may be a hinge vane type in which vanes separate from the rollers are rotatably fixed to the ends of the rollers.

[0027] The rotary compressor 1 comprises a casing 2, an electric motor 10, and a compression mechanism 15. The electric motor 10 and the compression mechanism 15 are each housed in the casing 2.

[0028] [Casing 2] Casing 2 is a cylindrical sealed container. Casing 2 comprises a body 3, an upper end plate 4, and a lower end plate 5. The ends of the body 3 are closed by the upper end plate 4 and the lower end plate 5, respectively. The casing 2 is sealed by the body 3 being closed by the pair of upper end plates 4 and lower end plates 5.

[0029] The body section 3 has a cylindrical shape. The suction pipe 7 and the suction pipe 8 are attached to the lower part of the body section 3, which is part of the casing 2. The upper end plate 4 and the lower end plate 5 are each dish-shaped. The discharge pipe 6 is attached to the upper end plate 4, which is part of the casing 2.

[0030] [Electric motor 10] The electric motor 10 drives the compression mechanism 15. The electric motor 10 is located in the upper part of the internal space of the casing 2. The electric motor 10 comprises a stator 11 and a rotor 12. The stator 11 is fixed to the body 3 of the casing 2. The stator 11 comprises, for example, coils and a stator core. The rotor 12 comprises, for example, permanent magnets. The rotor 12 is connected to a drive shaft 70 in the compression mechanism 15, which will be described later. The drive shaft 70 rotates around a rotation axis 70a that extends in the direction indicated by the arrow DZ.

[0031] [Compression mechanism 15] The compression mechanism 15 is a two-cylinder rotary fluid machine. The compression mechanism 15 is located below the electric motor 10 in the internal space of the casing 2. The compression mechanism 15 comprises a bearing section 20, a cylinder 30, a middle plate 50, a cylinder 35, and a bearing section 25. The compression mechanism 15 also comprises a piston 40 that rotates eccentrically in the cylinder chamber S1 of cylinder 30, and a piston 45 that rotates eccentrically in the cylinder chamber S2 of cylinder 35. Furthermore, the compression mechanism 15 comprises a drive shaft 70 that rotates around a rotation axis 70a along the vertical direction (direction indicated by arrow DZ).

[0032] (Bearing part 20) The bearing portion 20 comprises a main body portion 21, a main bearing portion 22, and an outer peripheral wall portion 23. The bearing portion 20 is formed by integrally molding the main body portion 21, the main bearing portion 22, and the outer peripheral wall portion 23.

[0033] The main body portion 21 has a disc-like shape. The main body portion 21 is positioned above and adjacent to the cylinder 30. The main body portion 21 is positioned to cover the upper end face of the cylinder 30. The lower surface of the main body portion 21 is in close contact with the cylinder 30.

[0034] The main bearing portion 22 is provided protruding upward from the main body portion 21. The main bearing portion 22 has a cylindrical shape. The main bearing portion 22 rotatably supports the drive shaft 70. The main bearing portion 22 constitutes a radial bearing.

[0035] The outer peripheral wall portion 23 has a thick, annular shape at the outer peripheral edge of the main body portion 21. The outer peripheral wall portion 23 is fixed to the body portion 3 of the casing 2.

[0036] The bearing section 20 has a discharge port 24. The discharge port 24 penetrates the main body section 21. The bearing section 20 is equipped with a discharge valve at the discharge port 24.

[0037] (Cylinder 30) The cylinder 30 forms a cylinder chamber S1 inside. The cylinder 30 has a cylindrical shape. The piston 40 rotates eccentrically within the cylinder chamber S1 of the cylinder 30. The cylinder 30 has a cylinder bore 31, a blade housing hole 32, and an intake hole 33.

[0038] The cylinder bore 31 is formed in the center of the cylinder 30. The piston 40 is housed in the cylinder bore 31. The cylinder bore 31 is a circular hole that penetrates the cylinder 30 in the thickness direction. The cylinder 30 has an inner circumferential surface 30S that forms the cylinder bore 31. The inner circumferential surface of the cylinder is a cylindrical surface with the rotation axis 70a of the drive shaft 70 as its central axis.

[0039] The blade housing hole 32 is a hole that extends radially from the inner circumferential surface 30S of the cylinder 30. The blade housing hole 32 penetrates the cylinder 30 in the thickness direction. The blade 42 of the piston 40 is housed in the blade housing hole 32. The blade 42 is pivotably held by a pair of bushings 43.

[0040] The intake hole 33 is a hole that extends radially from the inner circumferential surface 30S of the cylinder to the outside of the cylinder 30. The intake hole 33 is, for example, a hole with a circular cross-section.

[0041] (Middle Plate 50) The middle plate 50 is positioned between the cylinder 30 and the cylinder 35. The middle plate 50 has a disc-like shape. The middle plate 50 has a hole in its center through which the drive shaft 70 passes.

[0042] (Cylinder 35) The cylinder 35 forms a cylinder chamber S2 inside. The cylinder 35 has a cylindrical shape. The piston 45 rotates eccentrically within the cylinder chamber S2 of the cylinder 35. The cylinder 35 has a cylinder bore 36, a blade housing hole 37, and an intake hole 38.

[0043] The cylinder bore 36 is formed in the center of the cylinder 35. The piston 45 is housed in the cylinder bore 36. The cylinder bore 36 is a circular hole that penetrates the cylinder 35 in the thickness direction. The cylinder 35 has an inner circumferential surface 35S that forms the cylinder bore 36. The inner circumferential surface of the cylinder is a cylindrical surface with the rotation axis 70a of the drive shaft 70 as its central axis.

[0044] The blade housing hole 37 is a hole extending radially from the inner circumferential surface 35S of the cylinder 35. The blade housing hole 37 penetrates the cylinder 35 in the thickness direction. The blade 47 of the piston 45 is housed in the blade housing hole 37. The blade 47 is pivotably held by a pair of bushings 48.

[0045] The intake hole 38 is a hole that extends radially from the inner circumferential surface 35S of the cylinder to the outside of the cylinder 35. The intake hole 38 is, for example, a hole with a circular cross-section.

[0046] (Bearing part 25) The bearing portion 25 comprises a main body portion 26, a sub-bearing portion 27, and an outer peripheral wall portion 28. The bearing portion 25 is formed by integrally molding the main body portion 26, the sub-bearing portion 27, and the outer peripheral wall portion 28.

[0047] The main body portion 26 has a disc-like shape. The main body portion 26 is positioned below and adjacent to the cylinder 35. The main body portion 26 is positioned to cover the lower end surface of the cylinder 35. The upper surface of the main body portion 26 is in close contact with the cylinder 35.

[0048] The sub-bearing portion 27 is provided protruding downward from the main body portion 26. The sub-bearing portion 27 has a cylindrical shape. The sub-bearing portion 27 rotatably supports the drive shaft 70. The sub-bearing portion 27 constitutes a radial bearing.

[0049] The outer peripheral wall portion 28 has a thick, annular shape at the outer peripheral edge of the main body portion 26.

[0050] The bearing section 25 has a discharge port 29. The discharge port 29 penetrates the main body section 26. The bearing section 25 is equipped with a discharge valve at the discharge port 29.

[0051] (Drive shaft 70) The drive shaft 70 rotates around the rotation axis 70a. The drive shaft 70 has a main shaft portion 72, an eccentric portion 75, an intermediate connecting portion 78, an eccentric portion 76, and a sub-shaft portion 74. In the drive shaft 70, the main shaft portion 72, the eccentric portion 75, the intermediate connecting portion 78, the eccentric portion 76, and the sub-shaft portion 74 are formed integrally.

[0052] The main shaft portion 72 has a cylindrical or cylindrical shape with the rotating shaft 70a as its central axis. The upper end of the main shaft portion 72 is connected to the rotor 12 of the electric motor 10. The lower end of the main shaft portion 72 is rotatably supported by the main bearing portion 22. The lower end of the main shaft portion 72 constitutes a journal.

[0053] The eccentric portion 75 is a cylindrical part with a larger diameter than the main shaft portion 72. The central axis of the eccentric portion 75 is eccentric to the rotation axis 70a. The piston 40 is attached to the eccentric portion 75.

[0054] The intermediate connecting section 78 connects the eccentric section 75 and the eccentric section 76.

[0055] The eccentric portion 76 is a cylindrical part with a larger diameter than the main shaft portion 72. The central axis of the eccentric portion 76 is eccentric from the rotation axis 70a. The eccentric portion 76 is eccentric with respect to the rotation axis 70a on the opposite side from the eccentric portion 75. The piston 45 is attached to the eccentric portion 75.

[0056] The sub-shaft portion 74 has a cylindrical or cylindrical shape with the rotating shaft 70a as its central axis. The sub-shaft portion 74 is rotatably supported by the sub-bearing portion 27. The sub-shaft portion 74 constitutes a journal.

[0057] (Piston 40) The piston 40 rotates in the rotational direction RD. The piston 40 has a roller 41 and a blade 42. The piston 40 is formed integrally with the roller 41 and the blade 42. Not limited to the case where the roller 41 and the blade 42 are formed integrally, the blade 42 may be rotatably connected to the roller 41 at a predetermined position on the roller 41. The blade 42 divides the cylinder chamber S1 into an intake side space S1a and a discharge side space S1b.

[0058] The roller 41 is fixed to the eccentric portion 75 of the drive shaft 70. The roller 41 has an inner circumferential surface 41S1 which is a cylindrical surface centered on the central axis 41a, and an outer circumferential surface 41S2.

[0059] The outer surface 41S2 of the roller has a side surface 41S2a that includes a portion corresponding to the intake hole 33, and a side surface 41S2b other than side surface 41S2a. Side surface 41S2b has a shape along a virtual cylindrical surface 41S3 centered on the central axis 41a. Side surface 41S2a has a shape that is recessed from the virtual cylindrical surface 41S3 toward the central axis 41a. Due to side surface 41S2a, the roller 41 has a recess 41b that is recessed toward the central axis 41a. The recess 41b is sometimes called a piston cut. Side surface 41S2a is formed by a single plane.

[0060] The side surface 41S2a has a first end 41b1 located forward in the rotational direction RD and a second end 41b2 located rearward in the rotational direction RD. The first end 41b1 is formed at the connection point between the roller 41 and the blade 42. By forming the first end 41b1 at the connection point between the roller 41 and the blade 42, the range of the side surface 41S2a can be widened, thereby widening the range over which torque is generated. The second end 41b2 is located rearward in the rotational direction RD from the intake hole 33 when the second end 41b2 is closest to the inner circumferential surface 30S of the cylinder.

[0061] (Piston 45) The piston 45 has the same shape as the piston 40. The piston 45 has a roller 46 and a blade 47. The blade 47 divides the cylinder chamber S2 into an intake side space S2a and a discharge side space S2b. The roller 46 has an inner circumferential surface 46S1, which is a cylindrical surface centered on the central axis 46a, and an outer circumferential surface 46S2. The outer circumferential surface 46S2 has a side surface 46S2a that includes a portion corresponding to the intake hole 38, and a side surface 46S2b other than side surface 46S2a. Side surface 46S2b has a shape along a virtual cylindrical surface 46S3 centered on the central axis 46a. Side surface 46S2a has a shape that is recessed from the virtual cylindrical surface 46S3 toward the central axis 46a. Due to side surface 46S2a, the roller 46 has a recess 46b that is recessed from the virtual cylindrical surface 41S3 toward the central axis 46a. The recess 46b is sometimes called a piston cut. Details about piston 45 will be omitted here, as they should be referred to in the description of piston 40.

[0062] <Second Embodiment> In the rotary compressor according to the second embodiment, the first side surface is formed by a plurality of planes, compared to the rotary compressor according to the first embodiment.

[0063] The rotary compressor according to the second embodiment differs from the rotary compressor according to the first embodiment in the shape of its piston. The piston in the rotary compressor according to the second embodiment will be described in detail. Figure 3 is a cross-sectional view of piston 140, which is an example of a piston in the rotary compressor according to the second embodiment.

[0064] The piston 140 includes a roller 141 and a blade 142. The piston 140 is formed with the roller 141 and the blade 142 integrally. Not limited to the case where the roller 141 and the blade 142 are integrally formed, the blade 142 may be rotatably connected to the roller 141 at a predetermined position on the roller 141.

[0065] The roller 141 has an inner circumferential surface 141S1 which is a cylindrical surface centered on the central axis 141a, and an outer circumferential surface 141S2.

[0066] The outer surface 141S2 of the roller has a side surface 141S2a that includes a portion corresponding to the intake hole 33, and a side surface 141S2b other than side surface 141S2a. Side surface 141S2b has a shape along a virtual cylindrical surface 141S3 centered on the central axis 141a. Side surface 141S2a has a shape that is recessed from the virtual cylindrical surface 141S3 toward the central axis 141a. Due to side surface 141S2a, the roller 141 has a recess 141b that is recessed from the virtual cylindrical surface 141S3 toward the central axis 141a. The recess 141b is sometimes called a piston cut. Side surface 141S2a is formed by a plane 141S4 and a plane 141S5. Side surface 141S2a is a concave surface. In the above example, the number of planes is 2, but the number of planes is not limited to 2 and may be 3 or more.

[0067] <Third Embodiment> In the rotary compressor according to the third embodiment, the first side surface is formed by a plurality of planes, compared to the rotary compressor according to the first embodiment.

[0068] The rotary compressor according to the third embodiment differs from the rotary compressor according to the first embodiment in the shape of its piston. The piston in the rotary compressor according to the third embodiment will be described in detail. Figure 4 is a cross-sectional view of piston 240, which is an example of a piston in the rotary compressor according to the third embodiment.

[0069] The piston 240 has a roller 241 and a blade 242. The piston 240 is formed with the roller 241 and the blade 242 integrally. Not limited to the case where the roller 241 and the blade 242 are integrally formed, the blade 242 may be rotatably connected to the roller 241 at a predetermined position on the roller 241.

[0070] The roller 241 has an inner circumferential surface 241S1 which is a cylindrical surface centered on the central axis 241a, and an outer circumferential surface 241S2.

[0071] The outer surface 241S2 of the roller has a side surface 241S2a that includes a portion corresponding to the intake hole 33, and a side surface 241S2b other than side surface 241S2a. Side surface 241S2b has a shape along a virtual cylindrical surface 241S3 centered on the central axis 241a. Side surface 241S2a has a shape that is recessed from the virtual cylindrical surface 241S3 toward the central axis 241a. Due to side surface 241S2a, the roller 241 has a recess 241b that is recessed from the virtual cylindrical surface 241S3 toward the central axis 241a. The recess 241b is sometimes called a piston cut. Side surface 241S2a is formed by planes 241S4 and 241S5. Side surface 241S2a is convex. In the above example, the number of planes is 2, but the number of planes is not limited to 2 and may be 3 or more.

[0072] <Fourth Embodiment> The rotary compressor according to the fourth embodiment has a first side surface that is curved, compared to the rotary compressor according to the first embodiment.

[0073] The rotary compressor according to the fourth embodiment differs from the rotary compressor according to the first embodiment in the shape of its piston. The piston in the rotary compressor according to the fourth embodiment will be described in detail. Figure 5 is a cross-sectional view of piston 340, which is an example of a piston in the rotary compressor according to the fourth embodiment.

[0074] The piston 340 has a roller 341 and a blade 342. The piston 340 is formed integrally with the roller 341 and the blade 342. Not limited to the case where the roller 341 and the blade 342 are formed integrally, the blade 342 may be rotatably connected to the roller 341 at a predetermined position on the roller 341.

[0075] The roller 341 has an inner circumferential surface 341S1 which is a cylindrical surface centered on the central axis 341a, and an outer circumferential surface 341S2.

[0076] The outer surface 341S2 of the roller has a side surface 341S2a that includes a portion corresponding to the intake hole 33, and a side surface 341S2b other than side surface 341S2a. Side surface 341S2b has a shape along a virtual cylindrical surface 341S3 centered on the central axis 341a. Side surface 341S2a has a shape that is recessed from the virtual cylindrical surface 341S3 toward the central axis 341a. Due to side surface 341S2a, the roller 341 has a recess 341b that is recessed from the virtual cylindrical surface 341S3 toward the central axis 341a. The recess 341b is sometimes called a piston cut. Side surface 341S2a is formed by a curved surface 341S4, a flat surface 341S5, and a flat surface 341S6. Side surface 341S2a is a concave surface. In the above example, the number of surfaces constituting side surface 341S2a is 3, but the number of surfaces is not limited to 3; it may be 2 or 4 or more.

[0077] <Fifth Embodiment> The rotary compressor according to the fifth embodiment has a first side surface that is curved, compared to the rotary compressor according to the first embodiment.

[0078] The rotary compressor according to the fifth embodiment differs from the rotary compressor according to the first embodiment in the shape of its piston. The piston in the rotary compressor according to the fifth embodiment will be described in detail. Figure 6 is a cross-sectional view of piston 440, which is an example of a piston in the rotary compressor according to the fifth embodiment.

[0079] The piston 440 has a roller 441 and a blade 442. The piston 440 is formed with the roller 441 and the blade 442 as a single unit. Not limited to the case where the roller 441 and the blade 442 are formed as a single unit, the blade 442 may be rotatably connected to the roller 441 at a predetermined position on the roller 441.

[0080] The roller 441 has an inner circumferential surface 441S1 which is a cylindrical surface centered on the central axis 441a, and an outer circumferential surface 441S2.

[0081] The outer circumferential surface 441S2 of the roller has a side surface 441S2a that includes a portion corresponding to the intake hole 33, and a side surface 441S2b other than side surface 441S2a. Side surface 441S2b has a shape along a virtual cylindrical surface 441S3 centered on the central axis 441a. Side surface 441S2a has a shape that is recessed from the virtual cylindrical surface 441S3 toward the central axis 441a. Due to side surface 441S2a, the roller 441 has a recess 441b that is recessed from the virtual cylindrical surface 441S3 toward the central axis 441a. The recess 441b is sometimes called a piston cut. Side surface 441S2a is formed by curved surfaces 441S4 and 441S5. Side surface 441S2a is a concave surface. In the above example, the number of surfaces constituting side surface 441S2a is 2, but the number of surfaces is not limited to 2 and may be 3 or more.

[0082] The curved surface 441S4 is part of the cylindrical surface Ca1 having a central axis Ca1a. The curved surface 441S5 is part of the cylindrical surface Ca2 having a central axis Ca2a. The central axes Ca1a and Ca2a are positioned so as not to overlap with the straight line Lc connecting the center of the recess 441b and the central axis 441a.

[0083] <Operation of the rotary compressor according to this embodiment> The function of the first side surface of the piston on the rotor in the rotary compressor according to this embodiment will be described.

[0084] The coefficient of performance (COP), an indicator of compressor performance, is expressed as shown in Equation 1, using the compressor's input W and refrigeration capacity Q.

[0085] COP = Q / W ···(Equation 1)

[0086] For the same refrigeration capacity Q, a lower compressor input W improves the coefficient of performance (COP). A higher COP indicates better compressor performance.

[0087] In this embodiment, the rotary compressor has a first side surface on the rotor of the piston that includes a portion facing the intake hole, and the first side surface has a recessed shape (piston cut), thereby reducing the compressor input W relative to the refrigeration capacity Q. By reducing the compressor input W relative to the refrigeration capacity Q, the rotary compressor in this embodiment improves the coefficient of performance (COP).

[0088] Here, as shown in Figure 1, the angle between the line connecting the centerline of the piston blades and the central axis of the piston and the line connecting the second end and the central axis of the piston is defined as the piston cut angle θ. When the refrigerant is compressed by the piston, the volume displaced when the compression side space is closed by the piston is defined as the displaced volume Vcc.

[0089] The refrigeration capacity Q(θ) at the piston cut angle θ satisfies the relationship in Equation 2.

[0090] Q(θ) = ρ×Vcc(θ)×N×qL (Formula 2)

[0091] However, N represents the compressor rotational speed, and qL represents the change in enthalpy. Note that qL is constant regardless of the piston cut angle θ.

[0092] When the piston cut angle θ exceeds the angle θc between the line connecting the rotational end of the intake hole and the center of the piston, the displaced volume Vcc decreases. As long as the piston cut angle θ is smaller than angle θc, the intake hole is completely closed at the rotational end, and the displaced volume Vcc remains constant. On the other hand, when the piston cut angle θ is larger than angle θc, the closing is delayed, and the displaced volume Vcc decreases.

[0093] Therefore, with respect to the piston cut angle θ, the displaced volume Vcc remains constant up to angle θc, and decreases beyond angle θc. Consequently, with respect to the piston cut angle θ, the refrigeration capacity Q remains constant up to angle θc, and decreases beyond angle θc. The relationship between the piston cut angle θ and the refrigeration capacity Q is shown in Figure 7. Note that angle θc is 43°.

[0094] Furthermore, the displaced volume Vcc(θ) and the input W(θ) satisfy the relationship in Equation 3.

[0095] W(θ) = ρ×Vcc(θ)×N×w (Formula 3)

[0096] w is a constant independent of the piston cut angle θ.

[0097] The piston cut generates torque that rotates the piston due to the refrigerant (refrigerant jet) flowing in from the intake hole. This generated torque allows the roller to rotate in the rotational direction, particularly at the bottom dead center of the piston. In other words, the first side surface of the rotary compressor according to this embodiment has a shape that, at the bottom dead center, generates torque that causes the refrigerant jet from the intake hole to rotate the roller along the rotational direction.

[0098] Figure 8 shows the change in compressor input due to piston cutting. In Figure 8, the solid line represents the input to the piston of the rotary compressor according to this embodiment after piston cutting, and the dotted line represents the input to the piston without piston cutting.

[0099] According to the compressor of this embodiment, the input to the compressor can be reduced.

[0100] Figure 9 shows the results of calculating the coefficient of performance (COP) of the rotary compressor according to this embodiment by combining Equations 2 and 3.

[0101] The horizontal line in Figure 9 shows the coefficient of performance (COP) at angle θc (θc = 43°). As shown in Figure 9, the coefficient of performance (COP) can be improved compared to the coefficient of performance (COP) at angle θc in the range of piston cut angle θ up to 145°.

[0102] As described above, the rotary compressor according to this embodiment can reduce the input relative to the refrigeration capacity. By reducing the input relative to the refrigeration capacity, the rotary compressor according to this embodiment can improve the coefficient of performance (COP).

[0103] <Refrigeration equipment> A refrigeration system equipped with a rotary compressor according to this embodiment will be described. Figure 10 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.

[0104] 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.

[0105] First, we will explain the case where the refrigeration system 100 is cooled by the heat exchanger 105. Figure 10 shows the connections when the refrigeration system 100 is cooled by the heat exchanger 105.

[0106] 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.

[0107] 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.

[0108] Although 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 parts or all of other embodiments. [Explanation of Symbols]

[0109] 1. Rotary compressor 10 Electric motor 30, 35 cylinders 30S, 35S Cylinder inner surface 33, 38 Suction hole 40, 45, 140, 240, 340, 440 pistons 41, 46, 141, 241, 341, 441 Laura 41a, 46a, 141a, 241a, 341a, 441a center axis 41b, 46b, 141b, 241b, 341b, 441b recess 41b1, 46b1 1st end 41b2, 46b2 2nd end 41S1, 46S1, 141S1, 241S1, 341S1, 441S1 Roller inner circumference 41S2, 46S2, 141S2, 241S2, 341S2, 441S2 Roller outer circumference 41S2a, 41S2b, 46S2a, 46S2b, 141S2a, 141S2b, 241S2a, 241S2b, 341S2a, 341S2b, 441S2a, 441S2b Side 41S3, 46S3, 141S3, 241S3, 341S3, 441S3 virtual cylindrical surface 42, 47, 142, 242, 342, 442 blades 70 Drive shaft 70a Rotating shaft 75, 76 eccentric part 100 Refrigeration equipment 141S4, 141S5, 241S4, 241S5, 341S5, 341S6 plane 341S4, 441S4, 441S5 curved surface θ Piston cut angle

Claims

1. A drive shaft (70) that rotates around a first axis (70a) along a first direction (DZ) and has eccentric portions (75, 76), A cylinder (30, 35) having an inner circumferential surface (30S, 35S), and forming cylinder chambers (S1, S2) partitioned by the inner circumferential surface (30S, 35S), In the cylinder chambers (S1, S2), cylindrical rollers (41, 46, 141, 241, 341, 441) rotate eccentrically, Blades (42, 47, 142, 242, 342, 442) divide the cylinder chambers (S1, S2) into intake-side spaces (S1a, S2a) and discharge-side spaces (S1b, 2b), Equipped with, The rollers (41, 46, 141, 241, 341, 441) are fixed to the eccentric portions (75, 76) and have inner circumferential surfaces (41S1, 46S1, 141S1, 241S1, 341S1, 441S1) which are cylindrical surfaces centered on the second axis (41a, 46a, 141a, 241a, 341a, 441a), and outer circumferential surfaces (41S2, 46S2, 141S2, 241S2, 341S2, 441S2), The outer circumferential surface of the roller (41S2, 46S2, 141S2, 241S2, 341S2, 441S2) has a first side surface (41S2a, 46S2a, 141S2a, 241S2a, 341S2a, 441S2a) which includes a portion facing the intake hole (33, 38) on the intake side of the blade (42, 47, 142, 242, 342, 442), and a second side surface (41S2b, 46S2b, 141S2b, 241S2b, 341S2b, 441S2b) other than the first side surface (41S2a, 46S2a, 141S2a, 241S2a, 341S2a, 441S2b), The second side surfaces (41S2b, 46S2b, 141S2b, 241S2b, 341S2b, 441S2b) have a shape that aligns with a virtual cylindrical surface (41S3, 46S3, 141a, 241a, 341a, 441a) centered on the second axis (41a, 46a, 141a, 241a, 341a, 441a), The first side surfaces (41S2a, 46S2a, 141S2a, 241S2a, 341S2a, 441S2a) have a shape that is recessed from the virtual cylindrical surface (41S3, 46S3, 141S3, 241S3, 341S3, 441S3) toward the second axis (41a, 46a, 141a, 241a, 341a, 441a), and have a first end (41b1, 46b1) in the forward direction of rotation (RD) and a second end (41b2, 46b2) in the rear direction of rotation (RD). When the second end portions (41b2, 46b2) are closest to the inner circumferential surface of the cylinder (30S, 35S), the second end portions (41b2, 46b2) are positioned behind the intake holes (33, 38) in the rotational direction (RD). Rotary compressor (1).

2. The first side surface (41S2a, 46S2a, 141S2a, 241S2a, 341S2a, 441S2a) is composed of one or more planes. The rotary compressor (1) according to claim 1.

3. The first end portions (41b1, 46b1) are formed at the connection points between the rollers (41, 46, 141, 241, 341, 441) and the blades (42, 47, 142, 242, 342, 442). A rotary compressor (1) according to either claim 1 or claim 2.

4. The angle (θ) between the straight line connecting the center of the roller (41, 46, 141, 241, 341, 441) and the second end (41b2, 46b2) and the center line of the blade (42, 47, 142, 242, 342, 442) is between 43° and 145°. A rotary compressor (1) according to any one of claims 1 to 2.

5. The first side surfaces (41S2a, 46S2a, 141S2a, 241S2a, 341S2a, 441S2a) have a shape such that, at the bottom dead center, the refrigerant jet from the intake holes (33, 38) generates torque that causes the rollers (41, 46, 141, 241, 341, 441) to rotate along the rotational direction (RD). A rotary compressor (1) according to any one of claims 1 to 2.

6. A rotary compressor (1) according to any one of claims 1 to 2, Refrigeration device (100).

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