Electric valves and refrigeration cycle devices

Abstract

Motor-operated valve capable of suppressing deterioration of durability, and refrigeration cycle device having motor-operated valve and using natural refrigerant SOLUTION: The motor-operated valve 1 is incorporated into a refrigeration cycle device using a natural refrigerant. The electrically operated valve 1 has a valve body 30 and a drive mechanism 40 for driving the valve body 30. The natural refrigerant is introduced into the space inside the can 20 in which the drive mechanism 40 is disposed. The drive mechanism 40 has a drive shaft 41 having a male screw 42t and a shaft receiving member 45 having a female screw 42t to which the male screw 45t is screwed. Fluorine grease is applied to the drive shaft 41 and the bearing member 45.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to an electric valve and a refrigeration cycle device.

Background Art

[0002] A conventional electric valve is disclosed in Patent Document 1. The electric valve of Patent Document 1 is incorporated in, for example, a refrigeration cycle device and is used for controlling the flow rate of a refrigerant. The electric valve has a cam, a magnetic rotor, a reduction mechanism, a drive shaft, a bearing member, and a valve body. The magnetic rotor, the reduction mechanism, the drive shaft, and the bearing member are disposed inside the cam. Refrigerant is introduced inside the cam. The magnetic rotor is connected to the drive shaft via the reduction mechanism. The drive shaft has a male thread. The bearing member has a female thread into which the male thread is screwed. When the drive shaft rotates, the drive shaft moves in the axial direction. As the drive shaft moves, the valve body moves in the axial direction. The gears of the drive shaft, the bearing member, and the reduction mechanism are sliding parts, and grease is applied to the sliding parts.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a refrigeration cycle device, a natural refrigerant may be used. The natural refrigerant mainly contains, for example, carbon dioxide or propane. The natural refrigerant flows in a high-pressure state compared with a hydrofluorocarbon (HFC) refrigerant used in many refrigeration cycle devices.

[0005] The base oil of the grease applied to the sliding parts of electric valves is mainly composed of mineral oil or synthetic oil (ether-based oil, ester-based oil, etc.). Therefore, the grease has relatively high compatibility with the refrigeration oil that flows together with the refrigerant, and the grease may dissolve and decrease in volume.

[0006] In refrigeration cycle systems using HFC refrigerants, the difference in refrigerant pressure between the inlet and outlet of the electric valve is relatively small, resulting in less force being applied to the sliding parts. Therefore, even if the amount of grease decreases, lubrication can be compensated for by the refrigerant oil.

[0007] However, in refrigeration cycle systems using natural refrigerants, the difference in refrigerant pressure between the inlet and outlet of the electric valve is relatively large, resulting in significant force being applied to the sliding parts. Therefore, when the grease decreases, the lubrication cannot be compensated for by the refrigerant oil, which may reduce the durability of the sliding parts.

[0008] Therefore, the present invention aims to provide an electric valve that can suppress a decrease in durability, and a refrigeration cycle system that has an electric valve and uses a natural refrigerant. [Means for solving the problem]

[0009] To achieve the above objective, an electric valve according to one aspect of the present invention is an electric valve used in a refrigeration cycle device using a natural refrigerant, comprising a valve body, a drive mechanism for driving the valve body, and a case in which the drive mechanism is disposed inside, wherein the natural refrigerant is introduced inside the case, and the drive mechanism has sliding parts, and fluorine grease is applied to the sliding parts.

[0010] In the present invention, it is preferable that the drive mechanism comprises a magnet rotor, a reduction mechanism having a gear, a drive shaft having a male screw, and a bearing member having a female screw into which the male screw is threaded, wherein the magnet rotor is connected to the drive shaft via the reduction mechanism, and when the magnet rotor rotates, the drive shaft rotates and moves in the axial direction, the valve body moves in the axial direction in accordance with the movement of the drive shaft, and the drive shaft, the bearing member, and the gear are the sliding parts.

[0011] In the present invention, it is preferable that the drive mechanism comprises a magnetic rotor, a reduction mechanism having gears, a drive shaft, and a rotary valve body connected to the drive shaft, wherein the magnetic rotor is connected to the drive shaft via the reduction mechanism, and when the magnetic rotor rotates, the drive shaft and the rotary valve body rotate, and the gears are the sliding parts.

[0012] In the present invention, it is preferable that the drive mechanism comprises a magnet rotor, a male threaded member having a male screw, and a female threaded member having a female screw that is screwed into the male screw, and that one of the male threaded member and the female threaded member is a first member and the other is a second member, and that the magnet rotor is connected to the first member, and when the magnet rotor rotates, the first member rotates and moves axially relative to the second member, and the valve body moves axially in accordance with the movement of the first member relative to the second member, and that the first member and the second member are sliding parts.

[0013] In the present invention, it is preferable that the base oil of the fluorine grease mainly consists of perfluoropolyether, chlorotrifluoroethylene, or perfluoroalkyl ether.

[0014] In the present invention, it is preferable that the natural refrigerant mainly consists of carbon dioxide or propane, and that the refrigeration oil flowing together with the natural refrigerant mainly consists of polyol ester, polyalkylene glycol, or polyvinyl ether.

[0015] To achieve the above objective, another embodiment of the present invention is a refrigeration cycle device using a natural refrigerant, comprising an electric valve having a valve body, a drive mechanism for driving the valve body, and a case in which the drive mechanism is disposed inside, wherein the natural refrigerant is introduced inside the case, and the drive mechanism has sliding parts, and fluorine grease is applied to the sliding parts. [Effects of the Invention]

[0016] According to the present invention, the drive mechanism of the electric valve is located inside the case through which the natural refrigerant is introduced, and fluorine grease is applied to the sliding parts of the drive mechanism. The fluorine grease does not react with the main components of the natural refrigerant. Furthermore, the base oil of the fluorine grease is fluorine oil, and the base oil of the fluorine grease is not compatible with the refrigeration oil that flows together with the natural refrigerant, or has very low compatibility. Therefore, it is possible to suppress the dissolution of the fluorine grease in the electric valve and maintain the lubrication provided by the fluorine grease. Consequently, it is possible to suppress the deterioration of the durability of the sliding parts of the electric valve. [Brief explanation of the drawing]

[0017] [Figure 1] This is a block diagram of a refrigeration cycle device relating to one embodiment of the present invention. [Figure 2] Figure 1 is a longitudinal cross-sectional view of an electric valve in the refrigeration cycle device. [Figure 3] This is a magnified view of a portion of the electric valve shown in Figure 2. [Figure 4] This figure shows the test results regarding the reduction of grease due to refrigerant. [Figure 5] Figure 4 is a graph showing the test results. [Modes for carrying out the invention]

[0018] The following description of a refrigeration cycle device according to one embodiment of the present invention will be made with reference to Figures 1 to 3.

[0019] FIG. 1 is a block diagram of a refrigeration cycle apparatus according to an embodiment of the present invention. FIG. 2 is a longitudinal sectional view of an electric valve included in the refrigeration cycle apparatus of FIG. 1. FIG. 3 is an enlarged view of a part (a drive mechanism and its vicinity) of the electric valve of FIG. 2. In this specification, "up and down" indicates the up-and-down direction in each figure.

[0020] The refrigeration cycle apparatus 100 is, for example, an air conditioner. The refrigeration cycle apparatus 100 uses a natural refrigerant.

[0021] In the refrigeration cycle apparatus 100, a natural refrigerant and refrigeration machine oil are circulated. The natural refrigerant mainly contains carbon dioxide or propane. The refrigeration machine oil is, for example, polyalkylene glycol oil (PAG), polyol ester oil (POE), or polyvinyl ester oil (PVE).

[0022] As shown in FIG. 1, the refrigeration cycle apparatus 100 includes a compressor 101, a condenser 102, an electric valve 1, and an evaporator 103, which are connected in sequence via a pipe 105. The electric valve 1 is an expansion valve (pressure reducer). The refrigeration cycle apparatus 100 includes a control device 110. The control device 110 is connected to the electric valve 1. The control device 110 controls the flow rate of the natural refrigerant flowing through the pipe 105 using the electric valve 1.

[0023] As shown in FIGS. 2 and 3, the electric valve 1 includes a valve body 10, a can 20, a valve element 30, a drive mechanism 40, and a stator unit 70.

[0024] The valve body 10 includes a housing 11, a sleeve 14, and a connecting member 16.

[0025] The housing 11 has a cylindrical shape. The housing 11 integrally has a peripheral wall portion 11a and a bottom wall portion 11b. The bottom wall portion 11b is connected to the lower end of the peripheral wall portion 11a. The housing 11 has a valve chamber 12 and a valve opening 13. The valve opening 13 is located in the bottom wall portion 11b and opens into the valve chamber 12. An annular plane 11c facing upward is provided on the inner circumferential surface of the peripheral wall portion 11a. A transverse hole 11d is provided in the upper part of the peripheral wall portion 11a. A first conduit 18 is joined to the peripheral wall portion 11a. The first conduit 18 is connected to the valve chamber 12. A second conduit 19 is joined to the bottom wall portion 11b. The second conduit 19 is connected to the valve opening 13.

[0026] The sleeve 14 has a cylindrical shape. The sleeve 14 integrally comprises a first cylindrical portion 14a, a connecting portion 14b, a second cylindrical portion 14c, and a flange portion 14d. The inner diameter of the second cylindrical portion 14c is larger than the inner diameter of the first cylindrical portion 14a. The connecting portion 14b has an annular plate shape. The inner circumferential edge of the connecting portion 14b is connected to the upper end of the first cylindrical portion 14a, and the outer circumferential edge of the connecting portion 14b is connected to the lower end of the second cylindrical portion 14c. The flange portion 14d has an annular plate shape. The inner circumferential edge of the flange portion 14d is connected to the upper end of the second cylindrical portion 14c. The first cylindrical portion 14a, the connecting portion 14b, and the second cylindrical portion 14c are arranged in the valve chamber 12. The flange portion 14d is in contact with the plane 11c of the housing 11.

[0027] The connecting member 16 has an annular plate shape. A peripheral wall portion 11a is located inside the connecting member 16. The inner peripheral edge of the connecting member 16 is joined to the peripheral wall portion 11a.

[0028] The can 20 has a cylindrical shape. The can 20 is open at the lower end and closed at the upper end. The lower end of the can 20 is joined to the outer edge of the connecting member 16. The can 20 is a case.

[0029] The valve body 30 has a body portion 31, a valve portion 32, a spring receiving portion 33, and a ball receiving portion 34. The body portion 31 has a cylindrical shape. The outer diameter of the body portion 31 is the same as the inner diameter of the first cylindrical portion 14a of the sleeve 14. The valve portion 32 has a conical shape with its tip pointing downward. The valve portion 32 is connected to the lower end of the body portion 31. The valve portion 32 faces the valve opening 13 in the vertical direction (axis L direction). The spring receiving portion 33 has an annular shape. The outer diameter of the spring receiving portion 33 is larger than the outer diameter of the body portion 31. The spring receiving portion 33 is connected to the upper end of the body portion 31. The body portion 31, the valve portion 32, and the spring receiving portion 33 are integrally formed.

[0030] The body portion 31 is positioned inside the first cylindrical portion 14a and is supported by the first cylindrical portion 14a so as to be movable in the vertical direction. The body portion 31 is positioned inside the valve opening spring 35. The valve opening spring 35 is a compression coil spring. The valve opening spring 35 is positioned between the spring receiving portion 33 and the connection portion 14b of the sleeve 14. The valve opening spring 35 pushes the valve body 30 upward.

[0031] The ball bearing portion 34 integrally comprises a plate portion and a columnar projection connected to the lower surface of the plate portion. The projection is fitted into a hole provided on the upper end surface of the body portion 31.

[0032] The drive mechanism 40 moves the valve body 30 in the vertical direction. The drive mechanism 40 is located inside the can 20. The drive mechanism 40 includes a drive shaft 41, a bearing member 45, a magnet rotor 51, a connecting member 52, a rotor shaft 53, a support member 54, and a planetary gear mechanism 60.

[0033] The drive shaft 41 has a cylindrical portion 42, a flat plate portion 43, and a ball 44. The cylindrical portion 42 has a male thread 42t. The male thread 42t is located on the outer circumferential surface of the cylindrical portion 42. The flat plate portion 43 extends upward from the upper end surface of the cylindrical portion 42. The cylindrical portion 42 and the flat plate portion 43 are integrally formed. The ball 44 is joined to the lower end surface of the cylindrical portion 42. The drive shaft 41 is connected to the valve body 30. Specifically, the ball 44 of the drive shaft 41 is in slidable contact with the ball receiving portion 34 of the valve body 30.

[0034] The bearing member 45 has a cylindrical shape. The bearing member 45 is positioned inside the upper part of the peripheral wall portion 11a of the housing 11. The bearing member 45 is fixed to the peripheral wall portion 11a. The flange portion 14d of the sleeve 14 is held between the lower end surface of the bearing member 45 and the flat surface 11c of the peripheral wall portion 11a. The bearing member 45 has a female thread 45t. The female thread 45t is positioned at the lower part of the inner peripheral surface of the bearing member 45. The male thread 42t of the drive shaft 41 is screwed into the female thread 45t. Alternatively, the drive shaft 41 may have a female thread, and the bearing member 45 may have a male thread that is screwed into the female thread of the drive shaft 41.

[0035] The bearing member 45 has a vertical hole 45d and an annular groove 45e. The vertical hole 45d extends upward from the lower end surface of the bearing member 45. The annular groove 45e is located on the outer circumferential surface of the bearing member 45 and extends in the circumferential direction. The annular groove 45e is connected to the upper part of the vertical hole 45d. The annular groove 45e is connected to the transverse hole 11d of the circumferential wall portion 11a.

[0036] The natural refrigerant in the valve chamber 12 is introduced into the can 20 through the gap between the sleeve 14 and the valve body 30, the inside of the sleeve 14, the vertical hole 45d, the annular groove 45e, and the horizontal hole 11d. The refrigerant oil, which flows together with the natural refrigerant, is also introduced into the can 20.

[0037] The ball bearing portion 34, the drive shaft 41, and the bearing member 45 are preferably made of a metal such as stainless steel or brass. Furthermore, the ball bearing portion 34, the drive shaft 41, and the bearing member 45 are preferably subjected to a surface hardening treatment such as nitriding.

[0038] The magnet rotor 51 has a cylindrical shape. The connecting member 52 has a disc shape and is connected to the upper end of the magnet rotor 51. The magnet rotor 51 is connected to the rotor shaft 53 via the connecting member 52. The support member 54 has a disc shape. The support member 54 is positioned above the magnet rotor 51. The support member 54 rotatably supports the upper end of the rotor shaft 53.

[0039] The planetary gear mechanism 60 is a reduction mechanism that reduces the rotation of the magnet rotor 51. The planetary gear mechanism 60 connects the magnet rotor 51 and the drive shaft 41 and transmits the rotation of the magnet rotor 51 to the drive shaft 41. The planetary gear mechanism 60 is located inside the magnet rotor 51. The planetary gear mechanism 60 includes a gear case 61, a fixed ring gear 62, a sun gear 63, a plurality of planetary gears 64, a carrier 65, an output gear 66, and an output shaft 67.

[0040] The gear case 61 has a cylindrical shape. The gear case 61 is fixed to the upper part of the peripheral wall portion 11a of the housing 11. The fixed ring gear 62 is an internal gear. The fixed ring gear 62 is fixed to the upper part of the gear case 61. The sun gear 63 is coaxially connected to the lower surface of the connecting member 52. The sun gear 63 and the connecting member 52 are integrally formed. The rotor shaft 53 is inserted inside the sun gear 63. Multiple planetary gears 64 surround the sun gear 63. Multiple planetary gears 64 mesh with the fixed ring gear 62 and the sun gear 63. The carrier 65 has a plate shape. The carrier 65 has a support shaft that rotatably supports multiple planetary gears 64. The output gear 66 is an internal gear with a bottomed cylindrical shape. The output gear 66 meshes with the planetary gears 64. Each gear is preferably made of a metal such as stainless steel or brass, or an engineering plastic such as polytetrafluoroethylene (PTFE).

[0041] The output shaft 67 has a cylindrical shape. The lower part of the output shaft 67 is positioned inside the bearing member 45. The outer circumferential surface of the output shaft 67 and the inner circumferential surface of the bearing member 45 are in slidable contact. The output shaft 67 is rotatably supported by the bearing member 45. The upper part of the output shaft 67 is fixed to the bottom of the output gear 66, and the output shaft 67 rotates together with the output gear 66. The output shaft 67 has a bearing hole in which the lower end of the rotor shaft 53 is positioned. The output shaft 67 rotatably supports the lower end of the rotor shaft 53. Preferably, the output shaft 67 is made of a metal such as stainless steel or brass.

[0042] The output shaft 67 has a slit 67a that extends in the vertical direction. The slit 67a is located at the bottom of the output shaft 67. The width of the slit 67a is the same as the thickness of the flat plate portion 43 of the drive shaft 41. The output shaft 67 is connected to the drive shaft 41. Specifically, the flat plate portion 43 is positioned to move vertically within the slit 67a. When the output shaft 67 rotates, the flat plate portion 43 (drive shaft 41) rotates, and the flat plate portion 43 moves vertically within the slit 67a.

[0043] The stator unit 70 includes a stator 71 and a stator case 72. The stator 71 has a cylindrical shape. The stator 71 is located on the outside of the can 20. The stator 71 and the magnet rotor 51 constitute an electric motor. The stator case 72 is made of plastic and houses the stator 71. The stator unit 70 is fixed to the can 20.

[0044] The housing 11, valve port 13, sleeve 14, can 20, valve body 30, drive shaft 41, bearing member 45, magnet rotor 51, connecting member 52, rotor shaft 53, fixed ring gear 62, sun gear 63, output gear 66, and output shaft 67 each have their central axes coincide with axis L.

[0045] Next, we will explain the operation of the electric valve 1.

[0046] In the electric valve 1, the stator 71 is energized to rotate the magnet rotor 51 in one direction. The rotation of the magnet rotor 51 is transmitted to the drive shaft 41 via the planetary gear mechanism 60. When the drive shaft 41 rotates, the drive shaft 41 moves downward due to the lead screw action. The drive shaft 41 pushes the valve body 30 downward. As the valve body 30 moves downward, the valve portion 32 approaches the valve opening 13, and the opening of the valve opening 13 decreases.

[0047] In the electric valve 1, the stator 71 is energized to rotate the magnet rotor 51 in opposite directions. The rotation of the magnet rotor 51 is transmitted to the drive shaft 41 via the planetary gear mechanism 60. When the drive shaft 41 rotates, it moves upward due to the lead screw action. The valve body 30, pushed by the valve opening spring 35, moves upward, the valve portion 32 moves away from the valve opening 13, and the opening of the valve opening 13 increases.

[0048] When the electric valve 1 operates, the components of the drive mechanism 40 slide. Specifically, the male screw 42t of the drive shaft 41 slides against the female screw 45t of the bearing member 45 (S1), the connecting member 52 slides against the support member 54 (S2), the fixed ring gear 62 slides against the multiple planetary gears 64 (S3), the sun gear 63 slides against the multiple planetary gears 64 (S4), the output gear 66 slides against the multiple planetary gears 64 (S5), the bearing member 45 slides against the output gear 66 (S6), the bearing member 45 slides against the output shaft 67 (S7), the flat plate portion 43 of the drive shaft 41 slides against the inner surface of the slit 67a of the output shaft 67 (S8), and the ball bearing portion 34 slides against the ball 44 (S9). In Figure 3, the sliding locations are indicated by the symbols S1 to S9.

[0049] The drive shaft 41, bearing member 45, connecting member 52, support member 54, fixed ring gear 62, sun gear 63, multiple planetary gears 64, output gear 66, and output shaft 67 are sliding parts. Fluorine grease is applied to the sliding parts.

[0050] Fluorine grease comprises a base oil, a thickener, and a solid lubricant. The base oil is a fluorine oil, for example, an oil whose main components are perfluoropolyether (PFPE), chlorotrifluoroethylene (CTFE), or perfluoroalkyl ether (PFAE). The base oil does not have a chemical structure that reacts with the main components of natural refrigerants (carbon dioxide, propane). The base oil has no compatibility with the main components of natural refrigerants and refrigeration oils, or its compatibility is very low. In this embodiment, the thickener and solid lubricant are polytetrafluoroethylene (PTFE). PTFE has no compatibility with the main components of natural refrigerants and refrigeration oils, or its compatibility is very low. Therefore, fluorine grease does not dissolve in natural refrigerants and refrigeration oils, or the amount that dissolves in them is very small. Furthermore, instead of PTFE, other thickeners such as bentonite, soap-based materials (calcium soap, calcium complex, sodium soap, aluminum soap, aluminum complex, lithium soap, lithium complex), silica gel, and polyurea may be used, or these may be mixed with PTFE.

[0051] As described above, the refrigeration cycle device 100 using a natural refrigerant has an electric valve 1. The electric valve 1 has a valve body 30, a drive mechanism 40 that drives the valve body 30, and a can 20 in which the drive mechanism 40 is located. The natural refrigerant and refrigerant oil are introduced into the can 20.

[0052] The drive mechanism 40 includes a drive shaft 41, a bearing member 45, a magnet rotor 51, and a planetary gear mechanism 60. The drive shaft 41 has a male screw 42t. The bearing member 45 has a female screw 45t into which the male screw 42t is screwed. The planetary gear mechanism 60 includes gears (a fixed ring gear 62, a sun gear 63, multiple planetary gears 64, and an output gear 66). The magnet rotor 51 is connected to the drive shaft 41 via the planetary gear mechanism 60. When the magnet rotor 51 rotates, the drive shaft 41 rotates and moves vertically. The valve body 30 moves vertically in conjunction with the movement of the drive shaft 41. Fluorine grease is applied to the sliding parts, namely the drive shaft 41, the bearing member 45, and the gears.

[0053] Fluorine grease does not react with the main components of natural refrigerants. Furthermore, the base oil of fluorine grease is fluorine oil, and it is either incompatible or has very low compatibility with the refrigeration oil that flows together with the natural refrigerant. Therefore, it is possible to suppress the dissolution of fluorine grease into the natural refrigerant and refrigeration oil, and to maintain the lubrication provided by fluorine grease in the sliding parts. Consequently, it is possible to suppress the deterioration of the durability of the sliding parts of the electric valve 1.

[0054] The electric valve 1 may be configured without a reduction mechanism for reducing the rotation of the magnet rotor 51. In this configuration, for example, the drive mechanism 40 includes the magnet rotor 51, a drive shaft 41, and a bearing member 45. The drive shaft 41 has a male screw 42t. The bearing member 45 has a female screw 45t into which the male screw 42t is screwed. The magnet rotor 51 is directly connected to the drive shaft 41. The valve body 30 is directly connected to the lower end of the drive shaft 41. The rotation of the magnet rotor 51 is directly transmitted to the drive shaft 41. When the magnet rotor 51 rotates, the drive shaft 41 rotates and moves vertically relative to the bearing member 45. The drive shaft 41 is a male screw member and is the first member. The bearing member 45 is a female screw member and is the second member. The valve body 30 moves vertically as the drive shaft 41 moves. Furthermore, fluorine grease is applied to the sliding parts, the drive shaft 41 and the bearing member 45. The drive shaft 41 may have an internal thread, and the bearing member 45 may have a external thread that screws into the internal thread of the drive shaft 41.

[0055] Alternatively, the electric valve 1 may have a configuration in which, instead of a valve body 30 that moves in the vertical direction (axis L direction), a ball valve body (rotary valve body) that rotates around axis L. In this configuration, the drive mechanism 40 includes a magnetic rotor 51, a planetary gear mechanism 60, a drive shaft 41, and a ball valve body connected to the drive shaft 41. The magnetic rotor 51 is connected to the drive shaft 41 via the planetary gear mechanism 60. When the magnetic rotor 51 rotates, the drive shaft 41 and the ball valve body rotate. The drive shaft 41 does not move in the vertical direction (axial direction). Furthermore, fluorine grease is applied to the gears of the planetary gear mechanism 60, which are sliding parts.

[0056] These configurations also produce the same effects as the electric valve 1 described above.

[0057] The inventors conducted tests on the reduction of grease due to refrigerant and refrigeration oil using Examples 1 and 2 and Comparative Examples 1 and 2 of the present invention.

[0058] (Example 1) An assembly consisting of a magnetic rotor 51, a connecting member 52, a rotor shaft 53, and a planetary gear mechanism 60 was prepared. A specified amount of fluorine grease was applied to the sliding parts included in the assembly, and after measuring the weight of the assembly (initial weight), it was assembled into the electric valve 1. The fluorine grease used contained PFAE (base oil) and PTFE (thickener and solid lubricant) as its main components.

[0059] (Example 2) An assembly consisting of a magnet rotor 51, a connecting member 52, a rotor shaft 53, and a planetary gear mechanism 60 was prepared. A specified amount of fluorine grease was applied to the sliding parts included in the assembly, and the weight of the assembly (initial weight) was measured. Then, the assembly was immersed in refrigeration oil (temperature 120 degrees Celsius) for 96 hours and then assembled into the electric valve 1. The same fluorine grease as in Example 1 was used. The refrigeration oil used was one mainly composed of polyvinyl ether, which is used in refrigeration cycle devices using HFC refrigerant. Example 2 simulates the progression of the effects of refrigeration oil.

[0060] (Comparative Example 1) An assembly consisting of a magnetic rotor 51, a connecting member 52, a rotor shaft 53, and a planetary gear mechanism 60 was prepared. A specified amount of mineral oil-based grease was applied to the sliding parts included in the assembly, and after measuring the weight of the assembly (initial weight), it was assembled into the electric valve 1. The mineral oil-based grease used contained mineral oil (base oil), bentonite (thickener), and molybdenum disulfide (solid lubricant) as its main components.

[0061] (Comparative Example 2) An assembly consisting of a magnet rotor 51, a connecting member 52, a rotor shaft 53, and a planetary gear mechanism 60 was prepared. A specified amount of mineral oil-based grease was applied to the sliding parts included in the assembly, and the weight of the assembly (initial weight) was measured. Then, the assembly was immersed in refrigeration oil (temperature 120 degrees Celsius) for 96 hours and then assembled into the electric valve 1. The same mineral oil-based grease as in Comparative Example 1 was used. The same refrigeration oil as in Example 2 was used. Comparative Example 2 simulates the progression of the effects of refrigeration oil.

[0062] (test) A refrigerant supply device is connected to one conduit of the electric valve 1, and a refrigerant recovery device is connected to the other conduit. The refrigerant supply device fills the valve chamber 12 and can 20 of the electric valve 1 with liquid-phase refrigerant (excluding refrigerant oil), and the refrigerant recovery device recovers the refrigerant to empty the valve chamber 12 and can 20 (filling and recovery operation). In Example 1 and Comparative Example 1, if the grease is compatible with the refrigerant, the grease dissolves into the recovered refrigerant. In Example 2 and Comparative Example 2, if the grease is compatible with the refrigerant oil, the grease dissolves when immersed in the refrigerant oil and flows out from the applied area. Even if refrigerant oil or grease dissolved in refrigerant oil remains in the electric valve 1, the refrigerant oil dissolves into the refrigerant, so both the grease and refrigerant oil are recovered together with the refrigerant. After performing the filling and recovery operation a predetermined number of times, the assembly is removed from the electric valve 1 and the weight of the assembly is measured. The remaining amount of grease (%) is calculated from the measured weight. The refrigerant used is R410A (HFC refrigerant). The refrigeration oil used in the test is compatible with R410A. The test results for Examples 1 and 2 and Comparative Examples 1 and 2 are shown in Figures 4 and 5. Figure 4 is a table showing the number of fill-and-recovery operations and the amount of grease remaining. Figure 5 is a graph showing the relationship between the number of fill-and-recovery operations and the amount of grease remaining.

[0063] When the filling and recovery operation was repeated 20 times for Comparative Examples 1 and 2, the amount of grease in Comparative Example 1 hardly decreased, but the amount of grease in Comparative Example 2 decreased significantly. From this, it can be seen that mineral oil-based grease does not react with HFC refrigerant, but is compatible with refrigeration oil, and dissolves when the refrigeration oil flows together with the refrigerant.

[0064] When the filling and recovery operation was repeatedly performed on Examples 1 and 2, the amount of grease gradually decreased in both Examples 1 and 2 as the number of repetitions increased. The amount of grease decreased similarly in Examples 1 and 2, and there was no difference in the change in the amount of grease even when the effect of refrigeration oil was simulated. From this, it can be seen that fluorine grease is not compatible with refrigeration oil. The decrease in fluorine grease is presumed to be due to the reaction of the base oil of the fluorine grease with the HFC refrigerant. On the other hand, the base oil of the fluorine grease does not have a chemical structure that reacts with the main component of natural refrigerant. From this, it can be seen that fluorine grease does not dissolve in natural refrigerant or refrigeration oil. These test results support the effects of the present invention.

[0065] In this specification, terms indicating shapes such as "cylinder" and "column" are also used to refer to members or parts of members that substantially have the shape of those terms. For example, "cylindrical member" includes both cylindrical members and substantially cylindrical members. Furthermore, in this specification, the term "identical" may include both strictly identical and substantially identical items.

[0066] Although embodiments of the present invention have been described above, the present invention is not limited to these examples. Additions, deletions, and design modifications of components, or combinations of features of the embodiments as appropriate by those skilled in the art, are also included within the scope of the present invention, as long as they do not contradict the spirit of the invention. [Explanation of Symbols]

[0067] 1...Electric valve, 10...Valve body, 11...Housing, 11a...Circumferential wall, 11b...Bottom wall, 11c...Flat surface, 11d...Side hole, 12...Valve chamber, 13...Valve port, 14...Sleeve, 14a...First cylindrical part, 14b...Connecting part, 14c...Second cylindrical part, 14d...Flange part, 16...Connecting member, 18...First conduit, 19...Second conduit, 20...Can, 30...Valve body, 31...Body, 32...Valve part, 33...Spring receptacle, 34...Ball receptacle, 35...Opening spring, 40...Drive mechanism, 41...Drive shaft, 42...Cylindrical part, 42t...Male screw, 43...Flat plate part, 44...Ball, 45...Bearing member, 4 5d…vertical hole, 45e…annular groove, 45t…female thread, 51…magnet rotor, 52…connecting member, 53…rotor shaft, 54…support member, 60…planetary gear mechanism, 61…gear case, 62…fixed ring gear, 63…sun gear, 64…planetary gear, 65…carrier, 66…output gear, 67…output shaft, 67a…slit, 70…stator unit, 71…stator, 72…stator case, 100…refrigeration cycle device, 101…compressor, 102…condenser, 103…evaporator, 105…piping, 110…control device, L…axis, S1~S9…sliding parts

Claims

1. An electric valve used in a refrigeration cycle system using natural refrigerants, It comprises a valve body, a valve chamber, and a drive mechanism for driving the valve body, The aforementioned natural refrigerant is introduced into the space where the drive mechanism is located. The aforementioned drive mechanism has sliding parts, The sliding parts are coated with fluorine grease. The base oil of the aforementioned fluorine grease is mainly composed of perfluoropolyether, chlorotrifluoroethylene, or perfluoroalkyl ether. The aforementioned natural refrigerant mainly consists of carbon dioxide or propane. An electric valve characterized in that the refrigeration oil that flows together with the natural refrigerant mainly consists of polyol ester, polyalkylene glycol, or polyvinyl ether.

2. The drive mechanism comprises a magnetic rotor, a reduction mechanism having gears, a drive shaft having a male screw, and a bearing member having a female screw into which the male screw is threaded. The aforementioned magnet rotor is connected to the drive shaft via the reduction mechanism, When the magnet rotor rotates, the drive shaft rotates and moves in the axial direction. The valve body moves in the axial direction as the drive shaft moves. The electric valve according to claim 1, wherein the drive shaft, the bearing member, and the gear are the sliding parts.

3. The drive mechanism comprises a magnetic rotor, a reduction mechanism having gears, and a drive shaft. The valve body is a rotary valve body connected to the drive shaft, The aforementioned magnet rotor is connected to the drive shaft via the reduction mechanism, When the magnet rotor rotates, the drive shaft and the rotary valve body rotate. The electric valve according to claim 1, wherein the gear is the sliding component.

4. The drive mechanism comprises a magnetic rotor, a male threaded member having a male screw, and a female threaded member having a female screw that is screwed into the male screw. If one of the male threaded member and the female threaded member is designated as the first member and the other as the second member, the magnet rotor is connected to the first member, and when the magnet rotor rotates, the first member rotates and moves axially relative to the second member. The valve body moves in the axial direction as the first member moves relative to the second member. The electric valve according to claim 1, wherein the first member and the second member are the sliding parts.

5. A refrigeration cycle device using a natural refrigerant, The electric valve comprises a valve body having a valve element, a valve body having a valve chamber, and a drive mechanism for driving the valve element. The aforementioned natural refrigerant is introduced into the space where the drive mechanism is located. The aforementioned drive mechanism has sliding parts, The sliding parts are coated with fluorine grease. The base oil of the aforementioned fluorine grease is mainly composed of perfluoropolyether, chlorotrifluoroethylene, or perfluoroalkyl ether. The aforementioned natural refrigerant mainly consists of carbon dioxide or propane. A refrigeration cycle device characterized in that the refrigeration oil flowing together with the natural refrigerant is mainly composed of polyol ester, polyalkylene glycol, or polyvinyl ether.

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