Rotary compressor and refrigeration cycle apparatus

Abstract

A rotary compressor of an embodiment includes a cylinder, a shaft, a roller piston, and a vane. The vane has a distal end on a side of a cylinder chamber. The distal end has a hingedly-coupled portion. The hingedly-coupled portion is hingedly coupled to the roller piston. The roller piston has a groove portion formed on an outer circumference of the roller piston. The groove portion has a first cylindrical surface. The vane includes a vane main body and a bush. The bush is accommodated in the groove portion to constitute a hinged coupling. The bush has a second cylindrical surface sliding on the first cylindrical surface. The bush has a distance from a central axis of the second cylindrical surface. The distance of the bush is less than or equal to a curvature radius of the second cylindrical surface.

Description

CROSS-REFERENCE TO RELATED APPLICATION

[0001] Priority is claimed on Japanese Patent Application No. 2024-221518 filed on Dec. 18, 2024, the contents of which are incorporated herein by reference.BACKGROUND OF THE INVENTIONField of the Invention

[0002] An embodiment of the present invention relates to a rotary compressor and a refrigeration cycle apparatus.Description of Related Art

[0003] In a refrigeration cycle apparatus, a rotary compressor is used to compress a refrigerant. The rotary compressor includes a cylinder, a roller piston, and a vane. The cylinder has a cylinder chamber. The vane is accommodated in a slit in the cylinder. In a hinged vane type (vane-roller coupling structure) rotary compressor, a distal end of the vane on a side of the cylinder chamber is hingedly coupled to the roller piston. It is required that costs of the rotary compressor and the refrigeration cycle apparatus be reduced. For example, such rotary compressor and the refrigeration cycle apparatus are disclosed by Japanese Unexamined Patent Application, First Publication No. H8-151988, Japanese Unexamined Patent Application, First Publication No. 2023-5307, and PCT International Publication No. WO 2020 / 155923.

[0004] A problem to be solved by the present invention is to provide a rotary compressor and a refrigeration cycle apparatus in which it is possible to reduce the costs thereof.SUMMARY OF THE INVENTION

[0005] A rotary compressor according to a first aspect includes a cylinder, a shaft, a roller piston, and a vane. The cylinder has a cylindrical cylinder chamber. The cylindrical cylinder chamber is configured to compress a fluid suctioned in through a suction hole and discharge the compressed fluid through a discharge hole. The shaft is disposed coaxially with the cylinder chamber and has an eccentric portion inside the cylinder chamber. The eccentric portion is eccentric with respect to a central axis of the cylinder chamber. The roller piston is formed in a cylindrical shape. The roller piston is disposed coaxially with the eccentric portion. The roller piston is rotatable around the eccentric portion. The roller piston is configured to come into contact with a side surface of the cylinder chamber via an oil film. The vane is accommodated in a slit of the cylinder. The vane has a distal end on a side of the cylinder chamber. The distal end has a hingedly-coupled portion. The hingedly-coupled portion is hingedly coupled to the roller piston. The vane divides the cylinder chamber into a suction chamber on a side of the suction hole and a compression chamber on a side of the discharge hole. A direction of a central axis of the roller piston is defined as a first direction. The roller piston has a groove portion formed on an outer circumference of the roller piston. The groove portion has a first cylindrical surface extending in the first direction. The vane includes a vane main body and a bush. The vane main body has a distal end on the side of the cylinder chamber. The bush is attached to a distal end of the vane main body on a side of the cylinder chamber. The bush is accommodated in the groove portion to constitute the hingedly-coupled portion. The bush has a second cylindrical surface sliding on the first cylindrical surface. The bush has a distance from a central axis of the second cylindrical surface. The distance of the bush is less than or equal to a curvature radius of the second cylindrical surface.

[0006] The rotary compressor according to a second aspect is based on the rotary compressor according to the first aspect. The vane includes a mounting portion between the vane main body and the bush. The vane main body has a first surface. The bush has a second surface. In the mounting portion, the first surface of the vane main body and the second surface of the bush are disposed to face each other. In at least a part of the mounting portion in the first direction, a distance between the first surface and the second surface on a side of the suction chamber is greater than a distance between the first surface and the second surface on a side of the compression chamber.

[0007] The rotary compressor according to a third aspect is based on the rotary compressor according to the second aspect. The first surface has a cylindrical first hole formed in the first surface. The second surface has a cylindrical second hole formed in the second surface. The rotary compressor includes a cylindrical pin inserted across both the first hole and the second hole.

[0008] The rotary compressor according to a fourth aspect is based on the rotary compressor according to the third aspect. The first hole has a first diameter. The second hole has a second diameter. One of the first diameter and the second diameter is larger than the other diameter and larger than a diameter of the pin.

[0009] The rotary compressor according to a fifth aspect is based on the rotary compressor according to the fourth aspect. When a direction in which the vane main body and the bush are aligned is defined as a second direction, a side of the bush of the vane main body is defined as a first side in the second direction, and a side of the vane main body of the bush is defined as a second side in the second direction. The rotary compressor includes a restricting member. The restricting member restricts separation of the vane main body from the bush to the second side in the second direction. The rotary compressor does not include a biasing member biasing the vane main body to the first side in the second direction toward the bush.

[0010] The rotary compressor according to a sixth aspect is based on the rotary compressor according to the fifth aspect. The restricting member allows relative movement between the vane main body and the bush in the first direction.

[0011] The rotary compressor according to a seventh aspect is based on the rotary compressor according to the sixth aspect. The restricting member is a screw. The screw has a head portion, a body portion, and a distal end surface. The body portion has a male thread formed thereon. The vane main body has a screw hole having a female thread and a bottom surface. The head portion is accommodated in a counterbore hole formed on the first side of the bush in the second direction. The male thread of the body portion is screwed into the female thread of the screw hole of the vane main body. The distal end surface of the screw comes into contact with the bottom surface of the screw hole.

[0012] The rotary compressor according to an eighth aspect is based on the rotary compressor according to any one of the first to seventh aspects. A direction in which the vane main body and the bush are aligned is defined as a second direction, and a side of the bush of the vane main body is defined as a first side in the second direction. The roller piston has a lubricating-oil supply passage penetrating in a radial direction and opening into the groove portion. The bush has a bush recessed portion on the first side in the second direction. The bush recessed portion has a distance from a central axis of the second cylindrical surface. The distance of the bush recessed portion is smaller than a curvature radius of the second cylindrical surface. The lubricating-oil supply passage opens into the bush recessed portion.

[0013] The rotary compressor according to a ninth aspect is based on the rotary compressor according to any one of the first to eighth aspects. The roller piston is formed of aluminum or an aluminum alloy.

[0014] A refrigeration cycle apparatus according to an aspect includes a rotary compressor according to any one of the first to eighth aspects, a radiator connected to the rotary compressor, an expansion device connected to the radiator, and a heat absorber connected to the expansion device.BRIEF DESCRIPTION OF THE DRAWINGS

[0015] FIG. 1 is a circuit diagram of a refrigeration cycle apparatus and a cross-sectional view showing a rotary compressor according to an embodiment.

[0016] FIG. 2 is a cross-sectional view showing a compression mechanism portion taken along line II-II in FIG. 1.

[0017] FIG. 3 is an enlarged view showing an area including a bush shown in FIG. 2.

[0018] FIG. 4 is an enlarged view showing the bush shown in FIG. 2.

[0019] FIG. 5 is an exploded perspective view showing a vane.

[0020] FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 5.

[0021] FIG. 7 is a cross-sectional view taken along line VII-VII shown in FIG. 5.

[0022] FIG. 8 is a cross-sectional view taken along line VIII-VIII shown in FIG. 3.

[0023] FIG. 9 is an enlarged view showing an area including a pin shown in FIG. 8.

[0024] FIG. 10 is an enlarged view showing an area including a screw shown in FIG. 8.DETAILED DESCRIPTION OF THE INVENTION

[0025] Hereinafter, a rotary compressor and a refrigeration cycle apparatus according to an embodiment will be described with reference to the drawings.

[0026] FIG. 1 includes a circuit diagram of a refrigeration cycle apparatus 1 according to the embodiment. The refrigeration cycle apparatus 1 includes a rotary compressor 10, a four-way valve 3, a first heat exchanger 4, an expansion device 5, a second heat exchanger 6, and a refrigerant flow path 8. The refrigerant flow path 8 allows a refrigerant (fluid) to flow through the rotary compressor 10, the four-way valve 3, the first heat exchanger 4, the expansion device 5, and the second heat exchanger 6. The refrigerant circulates through the refrigeration cycle apparatus 1 while changing its phase.

[0027] The rotary compressor 10 compresses a low-pressure gaseous refrigerant taken into the inside into a high-temperature and high-pressure gaseous refrigerant. An accumulator (gas-liquid separator) 2b is disposed upstream of the rotary compressor 10. The accumulator 2b separates a gas-liquid two-phase refrigerant and supplies a gaseous refrigerant to the rotary compressor 10.

[0028] The four-way valve 3 reverses a flow direction of the refrigerant in the refrigerant flow path 8 of the first heat exchanger 4, the expansion device 5 and the second heat exchanger 6. When the four-way valve 3 is in a state shown in FIG. 1, the refrigerant discharged from the rotary compressor 10 flows through the first heat exchanger 4, the expansion device 5, and the second heat exchanger 6 in that order. At this time, the first heat exchanger 4 functions as a condenser (radiator). The second heat exchanger 6 functions as an evaporator (heat absorber).

[0029] When the four-way valve 3 is switched from the state shown in FIG. 1, the refrigerant discharged from the rotary compressor 10 flows through the second heat exchanger 6, the expansion device 5, and the first heat exchanger 4 in that order. At this time, the second heat exchanger 6 functions as a condenser (radiator). The first heat exchanger 4 functions as an evaporator (heat absorber).

[0030] The condenser dissipates heat from a high-temperature and high-pressure gaseous refrigerant discharged from the rotary compressor 10 to convert the high-temperature and high-pressure gaseous refrigerant into a high-pressure liquid refrigerant.

[0031] The expansion device 5 reduces a pressure of the high-pressure liquid refrigerant sent from the condenser to convert the high-pressure liquid refrigerant into a low-temperature and low-pressure gas-liquid two-phase refrigerant. For example, the expansion device 5 is an expansion valve.

[0032] The evaporator converts the gas-liquid two-phase refrigerant sent from the expansion device 5 into a low-pressure gaseous refrigerant. In the evaporator, the surroundings are cooled as the low-pressure gas-liquid two-phase refrigerant absorbs heat of vaporization from the surroundings while vaporizing. The low-pressure gaseous refrigerant that has passed through the evaporator is taken into the rotary compressor 10 described above via the accumulator 2b.

[0033] As described above, in the refrigeration cycle apparatus 1, the refrigerant, which is a working fluid, circulates while changing its phase between gas and liquid. The refrigerant releases heat in the process of a phase change from gas to liquid. Also, the refrigerant absorbs heat in the process of a phase change from liquid to gas. The refrigeration cycle apparatus 1 performs heating, cooling, defrosting, and the like by utilizing heat release or heat absorption of the refrigerant.

[0034] FIG. 1 includes a cross-sectional view showing the rotary compressor 10 according to an embodiment. The cross-sectional view showing the rotary compressor 10 corresponds to a cross-sectional view taken along line I-I shown in FIG. 2. FIG. 2 is a cross-sectional view showing a compression mechanism portion 20 taken along line II-II shown in FIG. 1.

[0035] In the present application, a T direction, an R direction, and a θ direction of a cylindrical coordinate system are defined as follows. The T direction is an axial direction of a case 11. A +T direction is a direction from the compression mechanism portion 20 toward an electric motor portion 14. For example, the T direction is a vertical direction, and the +T direction is vertically upward. The R direction is a radial direction of the case 11. A +R direction is a radially outward direction. The θ direction is a circumferential direction of the case 11. The +θ direction is a rotation direction of a right-handed screw that advances in the +T direction. Note that, directions opposite to the +T direction, the +R direction, and the +θ direction are defined as a −T direction, a −R direction, and a −θ direction, respectively.

[0036] As shown in FIG. 1, the rotary compressor 10 includes the case 11, the electric motor portion 14, a shaft 15, a first bearing 30, a second bearing 35, a partition plate 33, the compression mechanism portion 20, a first muffler 38a, and a second muffler 38b.

[0037] The case 11 is formed in a cylindrical shape with both end parts closed. The case 11 houses the electric motor portion 14, the shaft 15, and the compression mechanism portion 20. Lubricating oil 12 for lubricating the compression mechanism portion 20 is accommodated inside the case 11 in the-T direction. The gaseous refrigerant compressed by the compression mechanism portion 20 is accommodated inside the case 11 in the +T direction. The gaseous refrigerant and the lubricating oil inside the case 11 are at a high pressure. The gaseous refrigerant is supplied from a discharge port 13 in the +T direction of the case 11 and is supplied to the four-way valve 3 through the refrigerant flow path 8.

[0038] The electric motor portion 14 is disposed inside the case 11 in the +T direction. The electric motor portion 14 has a stator 14a and a rotor 14b. The stator 14a is fixed to an inner circumferential surface of the case 11. The rotor 14b is disposed in the −R direction of the stator 14a.

[0039] The shaft 15 is disposed coaxially with the case 11. The rotor 14b of the electric motor portion 14 is fixed to the shaft 15 in the +T direction. The shaft 15 has an eccentric portion 16 in the −T direction. The eccentric portion 16 is formed in a cylindrical shape. The eccentric portion 16 is eccentric with respect to a central axis of the case 11.

[0040] The first bearing (main bearing) 30 is disposed in the +T direction of the compression mechanism portion 20. The first bearing 30 has a bearing portion 31 and a closing portion 32. The bearing portion 31 of the first bearing 30 rotatably supports the shaft 15 in the +T direction of the compression mechanism portion 20. The closing portion 32 of the first bearing 30 closes an opening of the compression mechanism portion 20 in the +T direction.

[0041] The second bearing (auxiliary bearing) 35 is disposed in the −T direction of the compression mechanism portion 20. The second bearing 35 has a bearing portion 36 and a closing portion 37. The bearing portion 36 of the second bearing 35 rotatably supports the shaft 15 in the −T direction of the compression mechanism portion 20. The closing portion 37 of the second bearing 35 closes an opening of the compression mechanism portion 20 in the −T direction.

[0042] The compression mechanism portion 20 is disposed inside the case 11 in the −T direction. The compression mechanism portion 20 may be a single-cylinder compression mechanism portion having one cylinder chamber 22 or a multi-cylinder compression mechanism portion having a plurality of cylinder chambers 22. In the example shown in FIG. 1, the compression mechanism portion 20 has two cylinder chambers 22 aligned in the T direction.

[0043] The partition plate 33 is disposed between the two cylinder chambers 22.

[0044] The compression mechanism portion 20 includes, for each cylinder, a cylinder 21, a roller piston 40, and a vane (blade) 50 (refer to FIG. 2).

[0045] The cylinder 21 is disposed coaxially with the case 11. The cylinder 21 is fixed to the inner circumferential surface of the case 11. As shown in FIG. 2, the cylinder 21 has the cylinder chamber 22. The cylinder chamber 22 is formed inside a through hole that penetrates the cylinder 21 in the T direction. The cylinder chamber 22 is formed coaxially with the case 11. The eccentric portion 16 of the shaft 15 is disposed inside the cylinder chamber 22.

[0046] The roller piston 40 is formed in a cylindrical shape. The roller piston 40 is disposed coaxially with the eccentric portion 16. The roller piston 40 is rotatable around the eccentric portion 16. A part of an outer circumferential surface of the roller piston 40 comes into contact with an inner circumferential surface of the cylinder 21 (a side surface of the cylinder chamber 22) via an oil film (oil surface) having a thickness of several micrometers to tens of micrometers. A space between the outer circumferential surface of the roller piston 40 and the inner circumferential surface of the cylinder 21 substantially functions as the cylinder chamber 22.

[0047] The cylinder 21 has a suction hole 25 for the refrigerant and a discharge hole 26 for the refrigerant.

[0048] The suction hole 25 penetrates the case 11 and the cylinder 21 in the R direction. The suction hole 25 introduces the gaseous refrigerant supplied from the accumulator 2b shown in FIG. 1 into the cylinder chamber 22.

[0049] The discharge hole 26 penetrates the closing portion 32 of the first bearing 30 or the closing portion 37 of the second bearing 35 in the T direction. A reed valve is disposed on a side opposite to the cylinder chamber 22 across the discharge hole 26. The reed valve opens and closes the discharge hole 26 in accordance with a pressure in the cylinder chamber 22. The discharge hole 26 discharges the gaseous refrigerant compressed in the cylinder chamber 22 to the outside of the cylinder chamber 22.

[0050] As shown in FIG. 2, the vane 50 is accommodated in a slit 27 formed in the cylinder 21. The slit 27 penetrates the cylinder 21 in the T direction. The slit 27 extends, for example, in the R direction. An end part of the slit 27 in the-R direction opens into the cylinder chamber 22. A back pressure chamber 28 is formed at an end part of the slit in the +R direction. The high-pressure lubricating oil 12 (refer to FIG. 1) enters the back pressure chamber 28. A pressure of the lubricating oil 12 in the back pressure chamber 28 presses the vane 50 in the −R direction.

[0051] A distal end of the vane 50 in the −R direction is hingedly coupled to the roller piston 40. In other words, the distal end of the vane 50 in the −R direction has a hingedly-coupled portion. As the shaft 15 rotates, the eccentric portion 16 and the roller piston 40 revolve (eccentrically rotate) in the θ direction inside the cylinder chamber 22. As the roller piston 40 revolves, the vane 50 moves forward and backward in the R direction. The vane 50 divides the inside of the cylinder chamber 22 into a suction chamber 23 on a side of the suction hole 25 and a compression chamber 24 on a side of the discharge hole 26.

[0052] As shown in FIG. 1, the first muffler 38a is disposed on the side in the +T direction of the closing portion 32 of the first bearing 30. A first muffler chamber is formed between the first muffler 38a and the first bearing 30. The first muffler chamber accommodates the high-pressure gaseous refrigerant discharged from the discharge hole 26 of the first bearing 30.

[0053] The second muffler 38b is disposed on the side in the −T direction of the closing portion 37 of the second bearing 35. A second muffler chamber is formed between the second muffler 38b and the second bearing 35. The second muffler chamber accommodates the high-pressure gaseous refrigerant discharged from the discharge hole 26 of the second bearing 35.

[0054] The gaseous refrigerant in the second muffler chamber passes through a through hole (not shown in the drawings) that penetrates the cylinder 21 in the T direction and moves into the first muffler chamber. The gaseous refrigerant in the first muffler chamber is discharged into the inside of the case 11 from an opening of the first muffler 38a.

[0055] The vane 50 will be described in detail.

[0056] FIG. 3 is an enlarged view showing an area including a bush 60 shown in FIG. 2. A groove portion 42 is formed on an outer circumference of the roller piston 40. The groove portion 42 penetrates the roller piston 40 in the T direction. An inner surface of the groove portion 42 is a first cylindrical surface 42c extending in the T direction. An opening width of the groove portion 42 is smaller than a diameter of the bush 60 to be described later.

[0057] As shown in FIG. 2, the vane 50 includes a vane main body 51 and the bush 60.

[0058] The vane main body 51 is formed in a flat plate shape from a metal material such as iron, aluminum, or an aluminum alloy. Alternatively, the vane main body 51 may be formed using a resin, a ceramic, or a composite material containing a resin or a ceramic. The vane main body 51 is accommodated in the slit 27 of the cylinder 21. As shown in FIG. 3, the bush 60 is attached to a first surface 51s at a distal end of the vane main body 51 in the −R direction.

[0059] In the present application, as a local coordinate system of the vane 50, a Z direction, an X direction, and a Y direction of a Cartesian coordinate system are defined as follows. The Z direction is a height direction of the vane main body 51. For example, the Z direction corresponds to the T direction. A +Z direction corresponds to the +T direction. The Z direction (first direction) is also a direction of the central axis of the roller piston 40. The X direction is a length direction of the vane main body 51. For example, the X direction corresponds to the R direction. A +X direction corresponds to the −R direction. The X direction (second direction) is also a direction in which the vane main body 51 and the bush 60 are aligned. The +X direction (first side in the second direction) is a side of the bush 60 of the vane main body 51. A −X direction (second side in the second direction) is a side of the vane main body 51 of the bush 60. The Y direction is a width direction of the vane main body 51. For example, the Y direction corresponds to a tangential direction of the θ direction. Note that, directions opposite to the +Z direction, +X direction, and +Y direction are defined as a −Z direction, a −X direction, and a −Y direction, respectively.

[0060] FIG. 4 is an enlarged view showing the bush 60 shown in FIG. 2.

[0061] The bush 60 is made of a metal material such as high-speed tool steel. High-speed tool steel is easy to machine and excellent in wear resistance. As shown in FIG. 4, the bush 60 has a second cylindrical surface 60c. The second cylindrical surface 60c slides on the first cylindrical surface 42c (refer to FIG. 3) of the groove portion 42 of the roller piston 40. The bush 60 has a second surface 60s in the −X direction. As shown in FIG. 6, the first surface 51s of the vane main body 51 and the second surface 60s of the bush 60 are disposed to face each other at a mounting portion 50m between the vane main body 51 and the bush 60. For example, the second surface 60s is a flat surface. As shown in FIG. 4, the bush 60 has a bush recessed portion 64 in the +X direction. The bush recessed portion 64 is recessed to a side of a central axis 61 from a virtual plane that is an extension of the second cylindrical surface 60c. For example, a bottom surface 63 of the bush recessed portion 64 is a flat surface.

[0062] The bush 60 has a distance from the central axis 61 of the second cylindrical surface 60c. The distance of the bush 60 is less than or equal to a curvature radius 62 of the second cylindrical surface 60c. The bush 60 does not have a portion whose distance from the central axis 61 exceeds the curvature radius 62. Therefore, the bush 60 can be manufactured as follows. First, an intermediate material having a cylindrical shape is formed by cutting or grinding a base material while rotating it using a lathe or the like. An outer circumference of the intermediate material corresponds to the second cylindrical surface 60c. Next, the second surface 60s in the −X direction and the bottom surface 63 of the bush recessed portion 64 in the +X direction are formed by cutting the intermediate material using a milling machine or the like. Since the bush 60 can be manufactured in this manner, manufacturing costs of the bush 60 can be reduced. Moreover, an accuracy of a dimension, a surface roughness, cylindricity, and the like of the second cylindrical surface 60c is improved.

[0063] FIG. 5 is an exploded perspective view showing the vane 50. As described above, the vane 50 divides the cylinder chamber 22 into the suction chamber 23 and the compression chamber 24. The vane main body 51 has a recessed portion 52 extending from the first surface 51s in the +X direction toward a side surface on a side of the suction chamber 23. The recessed portion 52 opens to the side of the suction chamber 23 of the vane main body 51 and does not open to a side of the compression chamber 24. Two recessed portions 52 are formed separately in the +Z direction and the −Z direction of the first surface 51s. No recessed portion is formed at an end part of the first surface 51s on the side of the compression chamber 24 in the Y direction, and at a central part and both end parts thereof in the Z direction. A region of the first surface 51s in which the recessed portion 52 is not formed is a flat surface. That is, a flat surface extending throughout in the Z direction is formed at an end part of the first surface 51s on the side of the compression chamber 24. The recessed portion 52 may be formed continuously throughout the Z direction on the side of the suction chamber 23 of the first surface 51s.

[0064] FIG. 6 is a cross-sectional view taken along line VI-VI (a region in which the recessed portion 52 is not formed) shown in FIG. 5. As described above, the second surface 60s of the bush 60 in the −X direction is a flat surface. The first surface 51s of the vane main body 51 in the +X direction is flat in the region in which the recessed portion 52 is not formed. In the region in which the recessed portion 52 is not formed, the first surface 51s of the vane main body 51 and the second surface 60s of the bush 60 are in surface contact with each other. A distance between the first surface 51s and the second surface 60s on the side of the suction chamber 23 and a distance between the first surface 51s and the second surface 60s on the side of the compression chamber 24 are both zero.

[0065] FIG. 7 is a cross-sectional view taken along line VII-VII (a region in which the recessed portion 52 is formed) shown in FIG. 5. As described above, the recessed portion 52 opens to the side of the suction chamber 23 of the vane main body 51 and does not open to the side of the compression chamber 24. A distance between the first surface 51s and the second surface 60s on the side of the compression chamber 24 is zero. In the region in which the recessed portion 52 is formed, the first surface 51s of the vane main body 51 and the second surface 60s of the bush 60 are spaced apart. A gap G between the first surface 51s and the second surface 60s on the side of the suction chamber 23 is larger than a gap between the first surface 51s and the second surface 60s on the side of the compression chamber 24.

[0066] Thus, in at least a part of the mounting portion 50m in the Z direction, the distance between the first surface 51s and the second surface 60s on the side of the suction chamber 23 is larger than the distance between the first surface 51s and the second surface 60s on the side of the compression chamber 24. A low pressure of the gaseous refrigerant in the suction chamber 23 acts on the first surface 51s of the vane main body 51 in the +X direction. As shown in FIG. 2, a high pressure of the lubricating oil in the back pressure chamber 28 acts on an end surface of the vane main body 51 in the −X direction. Therefore, the vane main body 51 is pressed toward the bush 60 in the +X direction. The separation (vane jumping) between the vane main body 51 and the bush 60 is suppressed. Accordingly, generation of abnormal noise due to recontact between the vane main body 51 and the bush 60 is suppressed. Also, leakage of gaseous refrigerant from the compression chamber 24 to the suction chamber 23 is suppressed.

[0067] In the embodiment, the recessed portion 52 that opens to the side of the suction chamber 23 is formed in the first surface 51s of the vane main body 51. In contrast, a recessed portion that opens to the side of the suction chamber 23 may be formed in the second surface 60s of the bush 60. Also, a recessed portion that opens to the side of the suction chamber 23 may be formed on both the first surface 51s and the second surface 60s. Even in these cases, in at least a part of the mounting portion 50m in the Z direction, the distance between the first surface 51s and the second surface 60s on the side of the suction chamber 23 is greater than the distance between the first surface 51s and the second surface 60s on the side of the compression chamber 24.

[0068] In the embodiment, the region in which the recessed portion 52 is not formed on the first surface 51s of the vane main body 51 and the second surface 60s of the bush 60 are both flat surfaces. On the other hand, the first surface 51s and the second surface 60s in the region in which the recessed portion 52 is not formed may both be curved surfaces having the same shape. Therefore, in the region in which the recessed portion is not formed, the first surface 51s and the second surface 60s are disposed to face each other and come into surface contact.

[0069] As shown in FIG. 5, the vane 50 has a screw 70 and a pair of pins 78.

[0070] FIG. 8 is a cross-sectional view taken along line VIII-VIII shown in FIG. 3. The screw 70 is disposed at a center part of the mounting portion 50m in the Z direction. The pair of pins 78 are disposed separately in the +Z direction and the −Z direction of the mounting portion 50m. Central axes of the screw 70 and the pair of pins 78 extend in the X direction.

[0071] FIG. 9 is an enlarged view showing an area including the pin 78 shown in FIG. 8. The pin 78 has a cylindrical shape. The pin 78 may be a solid rod or a spring pin. A first hole 58 is formed in the first surface 51s of the vane main body 51. A second hole 68 is formed in the second surface 60s of the bush 60. The first hole 58 and the second hole 68 are both cylindrical in shape. Central axes of the first hole 58 and the second hole 68 extend in the X direction. The pin 78 is inserted across both the first hole 58 and the second hole 68. Therefore, misalignment between the vane main body 51 and the bush 60 in the Y direction is suppressed.

[0072] The first hole 58 has a first diameter. The second hole 68 has a second diameter. One of the first diameter and the second diameter is larger than the other diameter and is larger than a diameter of the pin 78. In the example shown in FIG. 9, the diameter of the first hole 58 is larger than the diameter of the second hole 68 and is larger than the diameter of the pin 78. The diameter of the second hole 68 is equal to or smaller than the diameter of the pin 78. The pin 78 is press-fitted into the second hole 68. Therefore, detachment of the pin 78 is suppressed. Also, the pin 78 is not press-fitted into the first hole 58. Therefore, assembly of the vane main body 51 and the bush 60 is facilitated. Note that, a gap is present between an end part of the pin 78 in the −X direction and a bottom part of the first hole 58.

[0073] Also, the diameter of the second hole 68 may be larger than the diameter of the first hole 58 and larger than the diameter of the pin 78. In this case, the diameter of the first hole 58 may be equal to or smaller than the diameter of the pin 78.

[0074] The pin 78 is press-fitted into the second hole 68 of the bush 60. The pin 78 is not press-fitted into the first hole 58 of the vane main body 51. A size of the bush 60 in the X direction is smaller than that of the vane main body 51. Work of press-fitting the pin 78 into the second hole 68 of the bush 60 in the X direction is easier than work of press-fitting the pin 78 into the first hole 58 of the vane main body 51.

[0075] FIG. 10 is an enlarged view showing an area including the screw 70 shown in FIG. 8. The screw 70 is a restricting member that restricts separation of the vane main body 51 from the bush 60 in the-X direction. As the restricting member, a rivet or the like may be employed instead of the screw 70. The screw 70 has a head portion 71 and a body portion 72. The head portion 71 is disposed at an end part in the +X direction, and the body portion 72 is disposed in the −X direction of the head portion 71. A male thread 73 is formed at an intermediate part of the body portion 72 in the X direction.

[0076] As described above, the bush recessed portion 64 is formed in the +X direction of the bush 60. A counterbore hole 65 is formed in the bottom surface 63 of the bush recessed portion 64. The head portion 71 of the screw 70 is accommodated inside the counterbore hole 65. A diameter of the counterbore hole 65 is larger than a diameter of the head portion 71. A gap is present between the bottom surface of the counterbore hole 65 and the head portion 71. A through hole is formed from the bottom surface of the counterbore hole 65 to the second surface 60s of the bush 60. A diameter of the through hole is smaller than the diameter of the head portion 71 and larger than a diameter of the body portion 72.

[0077] A cylindrical screw hole 55 is formed in the first surface 51s of the vane main body 51. A female thread 53 is formed in a region of the screw hole 55 in the +X direction. The male thread 73 of the screw 70 meshes (is screwed) with the female thread 53 of the screw hole 55. Therefore, the screw 70 restricts separation of the vane main body 51 from the bush 60 in the −X direction. The compression mechanism portion 20 shown in FIG. 2 does not have a biasing member that biases the vane main body 51 in the +X direction toward the bush 60. Even in this case, separation of the vane main body 51 from the bush 60 in the −X direction is suppressed. Since there is no biasing member, an inner diameter of the cylinder 21 can be increased. Therefore, a height of the cylinder 21 can be reduced, and a size of the rotary compressor 10 is reduced.

[0078] The female thread 53 is formed only in a region of the screw hole 55 in the +X direction. The female thread 53 is not formed in a region of the screw hole 55 in the −X direction. A diameter of the screw hole 55 is larger than the diameter of the body portion 72 of the screw 70. A bottom surface 56 of the screw hole 55 and a distal end surface 76 of the screw 70 are both flat surfaces. The distal end surface 76 of the screw 70 comes into contact with the bottom surface 56 of the screw hole 55. Therefore, the screw 70 is accurately disposed at a predetermined position in the X direction. A slight gap is secured between the head portion 71 of the screw 70 and the bottom surface of the counterbore hole 65. A size of the gap can be minimized, and the separation of the vane main body 51 from the bush 60 can be minimized.

[0079] As shown in FIG. 9, the diameter of the first hole 58 in the vane main body 51 is larger than the diameter of the pin 78 press-fitted into the bush 60. The vane main body 51 and the bush 60 are relatively movable in the Z direction within a clearance limit between the first hole 58 and the pin 78. The screw 70 allows relative movement between the vane main body 51 and the bush 60 in the Z direction.

[0080] Heights of the vane main body 51 and the bush 60 in the Z direction are slightly smaller than a height of the cylinder 21 in the Z direction. Therefore, the vane main body 51 and the bush 60 are movable inside the cylinder chamber 22. If it is assumed that the vane main body 51 and the bush 60 are rigidly joined by the screw 70, there is a possibility that the bush 60 may be fixed in a state protruding to one side in the Z direction from the vane main body 51. In this case, machining for removing the protruding portion of the bush 60 is necessary in a state in which the vane main body 51 and the bush 60 are rigidly joined together.

[0081] In contrast, the vane main body 51 and the bush 60 in the embodiment are relatively movable in the Z direction. The vane main body 51 and the bush 60 are not fixed in a state misaligned in the Z direction. With the vane main body 51 and the bush 60 rigidly joined together, machining for removing the protruding portion of the bush 60 is unnecessary. Therefore, manufacturing costs of the rotary compressor are reduced.

[0082] As shown in FIG. 3, the bush 60 is accommodated in the groove portion 42 of the roller piston 40. The first cylindrical surface 42c of the groove portion 42 and the second cylindrical surface 60c of the bush 60 are coaxially disposed and slide relative to each other. Therefore, an end part of the vane 50 in the +X direction is hingedly coupled to the roller piston 40. In other words, the end part of the vane 50 in the +X direction has a hingedly-coupled portion.

[0083] As described above, the lubricating oil 12 is accommodated in a lower part of the case 11 shown in FIG. 1. A first oil supply passage 17 is formed inside the shaft 15 along a central axis of the shaft 15. A pump (not shown in the drawings), such as a torsion plate, is provided inside the first oil supply passage 17. As the shaft 15 rotates, the pump draws up the lubricating oil12 from the lower part of the case 11. A second oil supply passage 18 is formed to penetrate the shaft 15 in a radial direction from the first oil supply passage 17 to an outer circumference of the shaft 15. The lubricating oil 12 passes through the second oil supply passage 18 and is supplied to sliding portions such as between the eccentric portion 16 and the roller piston 40.

[0084] As shown in FIG. 3, the roller piston 40 has a lubricating-oil supply passage 44. The lubricating-oil supply passage 44 penetrates the roller piston 40 in the radial direction and opens into the groove portion 42. As described above, the bush 60 has the bush recessed portion 64 in the +X direction. The lubricating-oil supply passage 44 opens into the bush recessed portion 64. The lubricating oil 12 passes through the lubricating-oil supply passage 44 to be stored in the bush recessed portion 64. The lubricating oil 12 is supplied from the bush recessed portion 64 to a sliding portion between the groove portion 42 and the bush 60. Therefore, the hinged coupling between the roller piston 40 and the vane 50 operates smoothly.

[0085] Accordingly, the roller piston 40 can be formed of a material such as aluminum or an aluminum alloy. Also, the vane main body 51 can be formed of a material such as aluminum or an aluminum alloy. Therefore, the rotary compressor 10 is reduced in weight. Also, vibration caused by eccentric rotation of the eccentric portion 16 and the roller piston 40 is suppressed. A weight of a balancer attached to the shaft 15 for reducing vibration can be reduced.

[0086] As described above in detail, the rotary compressor 10 of the embodiment includes the cylinder 21, the shaft 15, the roller piston 40, and the vane 50. The cylinder 21 has the cylindrical cylinder chamber 22 that compresses the fluid suctioned in through the suction hole 25 and discharges the compressed fluid from the discharge hole 26. The shaft 15 is disposed coaxially with the cylinder chamber 22. The shaft 15 has the eccentric portion 16 that is eccentric with respect to the central axis of the cylinder chamber 22 inside the cylinder chamber 22. The roller piston 40 is formed in a cylindrical shape. The roller piston 40 is disposed coaxially with the eccentric portion 16. The roller piston 40 is rotatable around the eccentric portion 16. The roller piston 40 can come into contact with a side surface of the cylinder chamber 22 via an oil film. The vane 50 is accommodated in the slit 27 of the cylinder 21. A distal end of the vane 50 on a side of cylinder chamber 22 is hingedly coupled to the roller piston 40. In other words, the distal end of the vane 50 on the side of cylinder chamber 22 has a hingedly-coupled portion. The vane 50 divides the cylinder chamber 22 into the suction chamber 23 on the side of the suction hole 25 and the compression chamber 24 on the side of the discharge hole 26. A direction of the central axis of the roller piston 40 is defined as the Z direction. The groove portion 42 having the first cylindrical surface 42c extending in the Z direction is formed on an outer circumference of the roller piston 40. The vane 50 includes the vane main body 51 and the bush 60. The bush 60 is attached to a distal end of the vane main body 51 on the side of cylinder chamber 22. The bush 60 is accommodated in the groove portion 42 to constitute the hingedly-coupled portion. The bush 60 has the second cylindrical surface 60c that slides on the first cylindrical surface 42c. The bush 60 has a distance from the central axis of the second cylindrical surface 60c. The distance of the bush 60 is less than or equal to the curvature radius 62 of the second cylindrical surface 60c.

[0087] According to this configuration, the second cylindrical surface 60c of the bush 60 can be formed by cutting the base material while rotating it. Therefore, costs of the rotary compressor 10 can be reduced.

[0088] At the mounting portion 50m between the vane main body 51 and the bush 60, the first surface 51s of the vane main body 51 and the second surface 60s of the bush 60 are disposed to face each other. In at least a part of the mounting portion 50m in the Z direction, the distance G between the first surface 51s and the second surface 60s on the side of the suction chamber 23 is larger than the distance between the first surface 51s and the second surface 60s on the side of the compression chamber 24.

[0089] According to this configuration, a low pressure of the gaseous refrigerant in the suction chamber 23 acts on the first surface 51s of the vane main body 51 in the +X direction. On the other hand, a high pressure of the lubricating oil in the back pressure chamber 28 acts on the end surface of the vane main body 51 in the −X direction. Therefore, the vane main body 51 is pressed toward the bush 60 in the +X direction. Separation between the vane main body 51 and the bush 60 is suppressed.

[0090] The cylindrical first hole 58 is formed in the first surface 51s, and the cylindrical second hole 68 is formed in the second surface 60s. The rotary compressor 10 has the cylindrical pin 78 inserted across both the first hole 58 and the second hole 68.

[0091] Therefore, misalignment between the vane main body 51 and the bush 60 in the Y direction is suppressed.

[0092] One of the first diameter of the first hole 58 and the second diameter of the second hole 68 is larger than the other diameter and is also larger than the diameter of the pin 78.

[0093] Therefore, detachment of the pin 78 is suppressed. Also, assembly of the vane main body 51 and the bush 60 is facilitated.

[0094] A direction in which the vane main body 51 and the bush 60 are aligned is defined as the X direction. The side of the bush 60 of the vane main body 51 is defined as the +X direction. The side of the vane main body 51 of the bush 60 is defined as the −X direction. The screw 70 restricting separation of the vane main body 51 from the bush 60 in the −X direction is provided. There is no biasing member that biases the vane main body 51 in the +X direction toward the bush 60.

[0095] Since there is no biasing member, an inner diameter of the cylinder 21 can be increased. Therefore, a height of the cylinder 21 can be reduced, and a size of the rotary compressor 10 is reduced.

[0096] The screw 70 allows relative movement between the vane main body 51 and the bush 60 in the Z direction. Therefore, the vane main body 51 and the bush 60 are not fixed in a state misaligned in the Z direction. Machining for removing a portion of the bush 60 protruding from the vane main body 51 is unnecessary. Therefore, manufacturing costs of the rotary compressor are reduced.

[0097] The head portion 71 of the screw 70 is accommodated in a counterbore hole 65 formed in the bush 60 in the +X direction. The male thread 73 formed on the body portion 72 of the screw 70 meshes with the female thread 53 formed in the screw hole 55 of the vane main body 51. The distal end surface 76 of the screw 70 comes into contact with the bottom surface 56 of the screw hole 55.

[0098] Therefore, the screw 70 is accurately disposed at a predetermined position in the X direction. A slight gap is secured between the head portion 71 of the screw 70 and the bottom surface of the counterbore hole 65. A size of the gap can be minimized, and the separation of the vane main body 51 from the bush 60 can be minimized.

[0099] A direction in which the vane main body 51 and the bush 60 are aligned is defined as the X direction. The side of the bush 60 of the vane main body 51 is defined as the +X direction. The roller piston 40 has the lubricating-oil supply passage 44 penetrating in the radial direction and opening into the groove portion 42. The bush 60 has, in the +X direction, the bush recessed portion 64 has a distance from the central axis of the second cylindrical surface 60c. The distance is smaller than the curvature radius 62 of the second cylindrical surface 60c. The lubricating-oil supply passage 44 opens into the bush recessed portion 64.

[0100] The lubricating oil 12 passes through the lubricating-oil supply passage 44 and is stored in the bush recessed portion 64. The lubricating oil 12 is supplied from the bush recessed portion 64 to a sliding portion between the groove portion 42 and the bush 60. Therefore, the hinged coupling between the roller piston 40 and the vane 50 operates smoothly.

[0101] Note that, the lubricating-oil supply passage 44 formed in the roller piston 40 may be a groove formed in an axial end surface of the roller piston 40 instead of a through hole. Particularly, when the lubricating-oil supply passage 44 is formed as a groove formed in the axial end surface of the roller piston 40 or as a through hole formed at a position near the axial end surface, the second oil supply passage 18, an axial end surface of the eccentric portion 16, and the lubricating-oil supply passage 44 can be kept in constant communication. Therefore, refrigeration machine oil can be constantly supplied to the side of the bush 60 during operation of the rotary compressor 10 without performing additional machining on the eccentric portion 16.

[0102] The roller piston 40 is formed of aluminum or an aluminum alloy. Therefore, the rotary compressor 10 is reduced in weight.

[0103] The refrigeration cycle apparatus 1 of the embodiment includes the above-described rotary compressor 10, one of the first heat exchanger 4 and the second heat exchanger 6 that functions as a radiator, the expansion device 5, and the other of the first heat exchanger 4 and the second heat exchanger 6 that functions as a heat absorber. The radiator is connected to the rotary compressor 10. The expansion device 5 is connected to the radiator. The heat absorber is connected to the expansion device 5.

[0104] By including the rotary compressor 10 described above, costs of the refrigeration cycle apparatus 1 can be reduced.

[0105] According to at least one of the embodiments described above, the rotary compressor 10 includes the bush 60 having a distance from the central axis of the second cylindrical surface 60c, and the distance of the bush 60 is less than or equal to the curvature radius 62 of the second cylindrical surface 60c. Therefore, costs of the rotary compressor 10 can be reduced.

[0106] While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.

Claims

1. A rotary compressor comprising:a cylinder having a cylindrical cylinder chamber, the cylindrical cylinder chamber being configured to compress a fluid suctioned in through a suction hole and discharge the compressed fluid through a discharge hole;a shaft disposed coaxially with the cylinder chamber, the shaft having an eccentric portion inside the cylinder chamber, the eccentric portion being eccentric with respect to a central axis of the cylinder chamber;a roller piston formed in a cylindrical shape, the roller piston being disposed coaxially with the eccentric portion, the roller piston being rotatable around the eccentric portion, the roller piston being configured to come into contact with a side surface of the cylinder chamber via an oil film; anda vane accommodated in a slit of the cylinder, the vane having a distal end on a side of the cylinder chamber, the distal end having a hingedly-coupled portion, the hingedly-coupled portion being hingedly coupled to the roller piston, the vane dividing the cylinder chamber into a suction chamber on a side of the suction hole and a compression chamber on a side of the discharge hole, whereinwhen a direction of a central axis of the roller piston is defined as a first direction, the roller piston has a groove portion formed on an outer circumference of the roller piston,the groove portion has a first cylindrical surface extending in the first direction,the vane includesa vane main body having a distal end on the side of the cylinder chamber, anda bush attached to the distal end of the vane main body, the bush being accommodated in the groove portion to constitute the hingedly-coupled portion,the bush has a second cylindrical surface sliding on the first cylindrical surface,the bush has a distance from a central axis of the second cylindrical surface, andthe distance of the bush is less than or equal to a curvature radius of the second cylindrical surface.

2. The rotary compressor according to claim 1, whereinthe vane includes a mounting portion between the vane main body and the bush,the vane main body has a first surface,the bush has a second surface,in the mounting portion, the first surface of the vane main body and the second surface of the bush are disposed to face each other, andin at least a part of the mounting portion in the first direction, a distance between the first surface and the second surface on a side of the suction chamber is greater than a distance between the first surface and the second surface on a side of the compression chamber.

3. The rotary compressor according to claim 2, whereinthe first surface has a cylindrical first hole formed in the first surface,the second surface has a cylindrical second hole formed in the second surface, andthe rotary compressor includes a cylindrical pin inserted across both the first hole and the second hole.

4. The rotary compressor according to claim 3, whereinthe first hole has a first diameter,the second hole has a second diameter, andone of the first diameter and the second diameter is larger than the other diameter and larger than a diameter of the pin.

5. The rotary compressor according to claim 4, whereinwhen a direction in which the vane main body and the bush are aligned is defined as a second direction, a side of the bush of the vane main body is defined as a first side in the second direction, and a side of the vane main body of the bush is defined as a second side in the second direction,the rotary compressor includes a restricting member,the restricting member restricts separation of the vane main body from the bush to the second side in the second direction, andthe rotary compressor does not include a biasing member biasing the vane main body to the first side in the second direction toward the bush.

6. The rotary compressor according to claim 5, whereinthe restricting member allows relative movement between the vane main body and the bush in the first direction.

7. The rotary compressor according to claim 6, whereinthe restricting member is a screw,the screw has a head portion, a body portion, and a distal end surface,the body portion has a male thread formed thereon,the vane main body has a screw hole having a female thread and a bottom surface,the head portion is accommodated in a counterbore hole formed on the first side of the bush in the second direction,the male thread of the body portion is screwed into the female thread of the screw hole of the vane main body, andthe distal end surface of the screw comes into contact with the bottom surface of the screw hole.

8. The rotary compressor according to claim 1, whereinwhen a direction in which the vane main body and the bush are aligned is defined as a second direction, and a side of the bush of the vane main body is defined as a first side in the second direction,the roller piston has a lubricating-oil supply passage penetrating in a radial direction and opening into the groove portion,the bush has a bush recessed portion on the first side in the second direction,the bush recessed portion has a distance from a central axis of the second cylindrical surface,the distance of the bush recessed portion is smaller than a curvature radius of the second cylindrical surface, andthe lubricating-oil supply passage opens into the bush recessed portion.

9. The rotary compressor according to claim 1, whereinthe roller piston is formed of aluminum or an aluminum alloy.

10. The rotary compressor according to claim 8, whereinthe roller piston is formed of aluminum or an aluminum alloy.

11. A refrigeration cycle apparatus comprising:a rotary compressor according to claim 1;a radiator connected to the rotary compressor;an expansion device connected to the radiator; anda heat absorber connected to the expansion device.

12. A refrigeration cycle apparatus comprising:a rotary compressor according to claim 2;a radiator connected to the rotary compressor;an expansion device connected to the radiator; anda heat absorber connected to the expansion device.

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