Motor-operated valve and refrigeration cycle apparatus

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 a motor-operated valve and a refrigeration cycle device. [Background technology]

[0002] A conventional motor-operated valve is disclosed in Patent Document 1. The motor-operated valve of Patent Document 1 is incorporated into, for example, a refrigeration cycle device and used to control the flow rate of a refrigerant. The motor-operated valve has a can, a magnet rotor, a reduction mechanism, a drive shaft, a bearing member, and a valve body. The magnet rotor, reduction mechanism, drive shaft, and bearing member are arranged inside the can. Refrigerant is introduced into the inside of the can. The magnet 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 threaded. When the drive shaft rotates, the drive shaft moves axially. The valve body moves axially as the drive shaft moves. The drive shaft, the bearing member, and the gears of the reduction mechanism are sliding parts, and grease is applied to the sliding parts. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-197849 Summary of the Invention [Problem to be solved by the invention]

[0004] Refrigeration cycle devices sometimes use natural refrigerants, such as those containing carbon dioxide or propane as their main component. Natural refrigerants flow at higher pressures than the hydrofluorocarbon (HFC) refrigerants used in many refrigeration cycle devices.

[0005] The base oil of the grease applied to the sliding parts of the motor-operated valve is primarily composed of mineral oil or synthetic oil (ether-based oil, ester-based oil, etc.). As a result, the grease is relatively compatible with the refrigeration oil that flows with the refrigerant, and the grease may dissolve and decrease.

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

[0007] However, in refrigeration cycle devices using natural refrigerants, the difference in refrigerant pressure between the inlet and outlet of the motor-operated valve is relatively large, which applies a large force to the sliding parts. As a result, when the grease runs out, the lubrication cannot be compensated for by the refrigeration oil, which may reduce the durability of the sliding parts.

[0008] Therefore, an object of the present invention is to provide an electric valve capable of suppressing a decrease in durability, and a refrigeration cycle device having the electric valve and using a natural refrigerant. [Means for solving the problem]

[0009] In order to achieve the above object, one aspect of the present invention provides an electric valve used in a refrigeration cycle device that uses a natural refrigerant, and is characterized in that it has a valve body, a drive mechanism that drives the valve body, and a case in which the drive mechanism is arranged, the natural refrigerant is introduced into the inside of the case, the drive mechanism has sliding parts, and the sliding parts are coated with fluorine grease.

[0010] In the present invention, it is preferable that the drive mechanism has a magnet rotor, a reduction mechanism having a gear, a drive shaft having a male thread, and a bearing member having a female thread into which the male thread is screwed, the 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 in conjunction 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 has a magnet rotor, a reduction mechanism having a gear, a drive shaft, and a rotary valve body connected to the drive shaft, the magnet rotor is connected to the drive shaft via the reduction mechanism, and when the magnet rotor rotates, the drive shaft and the rotary valve body rotate, and the gear is the sliding part.

[0012] In the present invention, it is preferable that the drive mechanism has a magnet rotor, a male screw member having a male screw, and a female screw member having a female screw that screws into the male screw, one of the male screw member and the female screw member being a first member and the other being a second member, the magnet rotor being 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 the first member and the second member are the sliding parts.

[0013] In the present invention, it is preferable that the base oil of the fluorine grease contains perfluoropolyether, chlorotrifluoroethylene or perfluoroalkyl ether as a main component.

[0014] In the present invention, it is preferable that the natural refrigerant contains carbon dioxide or propane as a main component, and the refrigerating machine oil that flows together with the natural refrigerant contains polyol ester, polyalkylene glycol, or polyvinyl ether as a main component.

[0015] In order to achieve the above object, a refrigeration cycle device according to another aspect of the present invention is a refrigeration cycle device that uses a natural refrigerant, and is characterized in that it has an electric valve having a valve body, a drive mechanism that drives the valve body, and a case in which the drive mechanism is arranged, the natural refrigerant is introduced into the inside of the case, the drive mechanism has sliding parts, and the sliding parts are coated with fluorine grease. [Effects of the Invention]

[0016] According to the present invention, the drive mechanism of the motor-operated valve is disposed inside a case into which a 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, which is incompatible with, or has very low compatibility with, the refrigeration oil that flows with the natural refrigerant. Therefore, the dissolution of the fluorine grease in the motor-operated valve can be suppressed, and the lubrication provided by the fluorine grease can be maintained. This suppresses a decrease in the durability of the sliding parts of the motor-operated valve. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a block diagram of a refrigeration cycle device according to an embodiment of the present invention. [Figure 2] 2 is a vertical cross-sectional view of a motor-operated valve included in the refrigeration cycle device of FIG. 1. [Figure 3] FIG. 3 is an enlarged view of a portion of the motor-operated valve of FIG. 2. [Figure 4] FIG. 10 is a diagram showing test results regarding grease reduction by refrigerant. [Figure 5] 5 is a graph showing the test results of FIG. 4. DETAILED DESCRIPTION OF THE INVENTION

[0018] A refrigeration cycle device according to one embodiment of the present invention will be described below with reference to FIGS.

[0019] Fig. 1 is a block diagram of a refrigeration cycle device according to one embodiment of the present invention. Fig. 2 is a vertical cross-sectional view of a motor-operated valve provided in the refrigeration cycle device of Fig. 1. Fig. 3 is an enlarged view of a part (a drive mechanism and its vicinity) of the motor-operated valve of Fig. 2. In this specification, "upper and lower" refers to the up and down directions in each drawing.

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

[0021] A natural refrigerant and refrigeration oil are circulated in the refrigeration cycle device 100. The natural refrigerant is mainly composed of carbon dioxide or propane. The refrigeration 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 has a compressor 101, a condenser 102, an electric valve 1, and an evaporator 103, which are connected in this order via a pipe 105. The electric valve 1 is an expansion valve (pressure reducer). The refrigeration cycle apparatus 100 has a control device 110. The control device 110 is connected to the electric valve 1. The control device 110 uses the electric valve 1 to control the flow rate of the natural refrigerant flowing through the pipe 105.

[0023] As shown in FIGS. 2 and 3, the motor-operated 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 includes 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 includes a valve chamber 12 and a valve port 13. The valve port 13 is disposed in the bottom wall portion 11b and opens into the valve chamber 12. The inner peripheral surface of the peripheral wall portion 11a is provided with an upwardly facing annular flat surface 11c. A horizontal hole 11d is provided in the upper portion 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 port 13.

[0026] The sleeve 14 has a cylindrical shape. The sleeve 14 integrally includes 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 flat plate shape. The inner peripheral edge of the connecting portion 14b is connected to the upper end of the first cylindrical portion 14a, and the outer peripheral 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 flat plate shape. The inner peripheral 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 disposed in the valve chamber 12. The flange portion 14d contacts a flat surface 11c of the housing 11.

[0027] The connecting member 16 has a circular flat plate shape. A peripheral wall portion 11a is disposed 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 lower end of the can 20 is open and the upper end is closed. The lower end of the can 20 is joined to the outer periphery of the connection member 16. The can 20 is a case.

[0029] The valve element 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 facing downward. The valve portion 32 is connected to the lower end of the body portion 31. The valve portion 32 faces the valve port 13 in the up-down direction (direction of the axis L). 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 31 is disposed inside the first cylindrical portion 14a and is supported by the first cylindrical portion 14a so as to be movable up and down. The body 31 is disposed inside the valve-opening spring 35. The valve-opening spring 35 is a compression coil spring. The valve-opening spring 35 is disposed between the spring receiving portion 33 and the connecting portion 14b of the sleeve 14. The valve-opening spring 35 presses the valve element 30 upward.

[0031] The ball receiving portion 34 integrally includes a plate portion and a pillar-shaped protrusion connected to the underside of the plate portion. The protrusion is fitted into a hole provided in the upper end surface of the body portion 31.

[0032] The drive mechanism 40 moves the valve element 30 in the vertical direction. The drive mechanism 40 is disposed inside the can 20. The drive mechanism 40 has 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 an external thread 42t. The external thread 42t is disposed on the outer peripheral 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 arranged 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 arranged on the lower part of the inner peripheral surface of the bearing member 45. The male thread 42t of the drive shaft 41 is threadedly engaged with the female thread 45t. It is to be noted that the drive shaft 41 may have a female thread, and the bearing member 45 may have a male thread that is threadedly engaged with 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 disposed on the outer peripheral surface of the bearing member 45 and extends in the circumferential direction. The annular groove 45e is connected to an upper portion of the vertical hole 45d. The annular groove 45e is connected to a horizontal hole 11d in the peripheral wall portion 11a.

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

[0037] The ball receiving portion 34, the drive shaft 41, and the bearing member 45 are preferably made of metal such as stainless steel or brass, and 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 disk shape and is connected to the upper end of the magnet rotor 51. The magnet rotor 51 is connected to a rotor shaft 53 via the connecting member 52. The support member 54 has a disk shape. The support member 54 is disposed 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 speed 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 disposed inside the magnet rotor 51. The planetary gear mechanism 60 has a gear case 61, a fixed ring gear 62, a sun gear 63, a plurality of planet 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 formed integrally. The rotor shaft 53 is inserted inside the sun gear 63. A plurality of planetary gears 64 surround the sun gear 63. The plurality of 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 the plurality of planetary gears 64. The output gear 66 is an internal gear having a cylindrical shape with a bottom. 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 disposed inside the bearing member 45. The outer peripheral surface of the output shaft 67 and the inner peripheral surface of the bearing member 45 are in slidable contact with each other. 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 part 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 disposed. The output shaft 67 rotatably supports the lower end of the rotor shaft 53. The output shaft 67 is preferably made of a metal such as stainless steel or brass.

[0042] The output shaft 67 has a slit 67a extending 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 located in the slit 67a so as to be movable in the vertical direction. When the output shaft 67 rotates, the flat plate portion 43 (drive shaft 41) rotates, and the flat plate portion 43 moves in the vertical direction within the slit 67a.

[0043] The stator unit 70 has a stator 71 and a stator case 72. The stator 71 has a cylindrical shape. The stator 71 is arranged outside the can 20. The stator 71 and the magnet rotor 51 form 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 a central axis that coincides with the axis L.

[0045] Next, the operation of the motor-operated valve 1 will be described.

[0046] In the motor-operated 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 feed screw action. The drive shaft 41 pushes the valve disc 30 downward. As the valve disc 30 moves downward, the valve portion 32 approaches the valve orifice 13, and the opening of the valve orifice 13 decreases.

[0047] In the motor-operated valve 1, the stator 71 is energized to rotate the magnet rotor 51 in the other 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 upward due to the feed screw action. The valve disc 30, pressed by the valve-opening spring 35, moves upward, and the valve portion 32 moves away from the valve orifice 13, increasing the opening of the valve orifice 13.

[0048] When the motor-operated valve 1 operates, the components of the drive mechanism 40 slide. Specifically, the male thread 42t of the drive shaft 41 slides against the female thread 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 plurality of planetary gears 64 (S3), the sun gear 63 slides against the plurality of planetary gears 64 (S4), the output gear 66 slides against the plurality of 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 receiver 34 slides against the ball 44 (S9). In FIG. 3, the sliding locations are indicated by symbols S1 to S9.

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

[0050] The fluorine grease includes a base oil, a thickener, and a solid lubricant. The base oil is a fluorine oil, for example, an oil whose main component is 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 is incompatible with the main components of natural refrigerants and refrigeration oil, or has very low compatibility. In this embodiment, the thickener and the solid lubricant are polytetrafluoroethylene (PTFE). PTFE is incompatible with the main components of natural refrigerants and refrigeration oil, or has very low compatibility. Therefore, the fluorine grease does not dissolve in natural refrigerants and refrigeration oil, or the amount that dissolves in these components is very small. Instead of PTFE, the thickener may be, for example, bentonite, a soap-based agent (calcium soap, calcium complex, sodium soap, aluminum soap, aluminum complex, lithium soap, lithium complex), silica gel, or polyurea, or these may be mixed with PTFE and used.

[0051] As described above, the refrigeration cycle device 100 using a natural refrigerant has the motor-operated valve 1. The motor-operated valve 1 has the valve element 30, the drive mechanism 40 that drives the valve element 30, and the can 20 inside which the drive mechanism 40 is disposed. The natural refrigerant and refrigeration oil are introduced into the inside of the can 20.

[0052] The drive mechanism 40 has 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 thread 42t. The bearing member 45 has a female thread 45t into which the male thread 42t is threaded. The planetary gear mechanism 60 has 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 up and down. The valve body 30 moves up and down as the drive shaft 41 moves. Fluorine grease is applied to the sliding parts of 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, which is incompatible with, or has very low compatibility with, the refrigeration oil that flows with the natural refrigerant. This prevents the fluorine grease from dissolving into the natural refrigerant and the refrigeration oil, maintaining the lubrication provided by the fluorine grease in the sliding parts. This prevents a decrease in the durability of the sliding parts of the motor-operated valve 1.

[0054] The motor-operated valve 1 may be configured without a speed reduction mechanism for reducing the rotation speed of the magnet rotor 51. In this configuration, for example, the drive mechanism 40 has the magnet rotor 51, a drive shaft 41, and a bearing member 45. The drive shaft 41 has a male thread 42t. The bearing member 45 has a female thread 45t into which the male thread 42t is threaded. The magnet rotor 51 is directly connected to the drive shaft 41. The valve element 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 up and down relative to the bearing member 45. The drive shaft 41 is a male thread member and is a first member. The bearing member 45 is a female thread member and is a second member. The valve element 30 moves up and down as the drive shaft 41 moves. Fluorine grease is applied to the sliding parts, that is, the drive shaft 41 and the bearing member 45. 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.

[0055] Alternatively, the motor-operated valve 1 may have a ball valve element (rotating valve element) that rotates around the axis L, instead of the valve element 30 that moves up and down (in the direction of the axis L). In this configuration, the drive mechanism 40 has a magnet rotor 51, a planetary gear mechanism 60, a drive shaft 41, and a ball valve element connected to the drive shaft 41. 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 and the ball valve element rotate. The drive shaft 41 does not move up and down (in the axial direction). Fluorine grease is applied to the gears of the planetary gear mechanism 60, which are sliding parts.

[0056] These configurations also provide the same effects as the motor-operated valve 1 described above.

[0057] The present inventors conducted tests on the reduction of grease by refrigerant and refrigerating machine oil using Examples 1 and 2 of the present invention and Comparative Examples 1 and 2.

[0058] Example 1 An assembly was prepared, consisting of a magnet rotor 51, a connecting member 52, a rotor shaft 53, and a planetary gear mechanism 60. A specified amount of fluorine grease was applied to the sliding parts included in the assembly, and the weight (initial weight) of the assembly was measured, and then the assembly was incorporated into the motor-operated 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 (initial weight) of the assembly was measured. The assembly was then immersed in refrigeration oil (temperature 120°C) for 96 hours, and then incorporated into the motor-operated valve 1. The same fluorine grease as in Example 1 was used. The refrigeration oil used was one containing polyvinyl ether as its main component, which is used in refrigeration cycle devices using HFC refrigerants. Example 2 simulates the progression of the effects of refrigeration oil.

[0060] (Comparative Example 1) An assembly was prepared, consisting of a magnet rotor 51, a connecting member 52, a rotor shaft 53, and a planetary gear mechanism 60. A specified amount of mineral oil-based grease was applied to the sliding parts included in the assembly, and the weight (initial weight) of the assembly was measured, and then the assembly was incorporated into the motor-operated 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 (initial weight) of the assembly was measured. The assembly was then immersed in refrigeration oil (temperature 120°C) for 96 hours, and then incorporated into the motor-operated valve 1. The mineral oil-based grease used was the same as in Comparative Example 1. The refrigeration oil used was the same as in Example 2. 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 motor-operated 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 motor-operated valve 1 with liquid refrigerant (not including refrigerant oil), and the refrigerant is recovered using the refrigerant recovery device, emptying the valve chamber 12 and can 20 (a filling and recovery operation). In Example 1 and Comparative Example 1, if the grease is compatible with the refrigerant, the grease dissolves in 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 application area. Even if refrigerant oil or grease dissolved in the refrigerant oil remains in the motor-operated valve 1, the refrigerant oil dissolves in the refrigerant, and both the grease and the refrigerant oil are recovered along with the refrigerant. After performing the filling and recovery operation a predetermined number of times, the assembly is removed from the motor-operated valve 1 and its weight is measured. The remaining grease amount (%) 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 charging and recovery operations and the remaining amount of grease. Figure 5 is a graph showing the relationship between the number of charging and recovery operations and the remaining amount of grease.

[0063] When the charging and recovering operation was repeated 20 times for Comparative Examples 1 and 2, there was almost no reduction in the amount of grease in Comparative Example 1, but there was a significant reduction in the amount of grease in Comparative Example 2. This shows that mineral oil-based grease does not react with HFC refrigerants, but is compatible with refrigerating machine oil, and dissolves when the refrigerating machine oil flows together with the refrigerant.

[0064] When the filling and recovery operation was repeated for Examples 1 and 2, the grease gradually decreased with increasing number of times in both Examples 1 and 2. The grease decreased in the same way in Examples 1 and 2, and there was no difference in the change in the remaining grease amount even when the influence of refrigeration oil was simulated. This shows that fluorine grease is not compatible with refrigeration oil. It is presumed that the decrease in fluorine grease is caused by 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 refrigerants. This suggests that fluorine grease does not dissolve in natural refrigerants or refrigeration oil. These test results support the effects of the present invention.

[0065] In this specification, terms indicating a shape, such as "cylinder" or "column," are also used to refer to members or portions of members that have substantially the shape of the term. For example, a "cylindrical member" includes both cylindrical members and substantially cylindrical members. In addition, in this specification, the term "same" can include both strictly identical and substantially identical.

[0066] Although the embodiments of the present invention have been described above, the present invention is not limited to these examples. Any modifications, additions, deletions, or design changes of components made by a person skilled in the art to the above-described embodiments, or any combinations of features of the embodiments, are also included within the scope of the present invention as long as they do not deviate from the spirit of the present invention. [Explanation of symbols]

[0067] 1...motor-operated valve, 10...valve body, 11...housing, 11a...circumferential wall portion, 11b...bottom wall portion, 11c...flat surface, 11d...horizontal hole, 12...valve chamber, 13...valve port, 14...sleeve, 14a...first cylindrical portion, 14b...connection portion, 14c...second cylindrical portion, 14d...flange portion, 16...connection member, 18...first conduit, 19...second conduit, 20...can, 30...valve body, 31...body portion, 32...valve portion, 33...spring receiving portion, 34...ball receiving portion, 35...valve opening spring, 40...drive mechanism, 41...drive shaft, 42...cylindrical portion, 42t...male thread, 43...flat plate portion, 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 to S9...sliding points

Claims

1. An electric valve used in a refrigeration cycle device using a natural refrigerant, a valve body having a valve element, a valve chamber, a drive mechanism for driving the valve element, and a case in which the drive mechanism is disposed, The case has a cylindrical shape, one end is open and the other end is closed, One end of the case is joined to the valve body, The natural refrigerant is introduced into the inside of the case, the drive mechanism has a sliding part; Fluorine grease is applied to the sliding parts, The base oil of the fluorine grease contains perfluoropolyether, chlorotrifluoroethylene or perfluoroalkyl ether as a main component, The natural refrigerant is mainly composed of carbon dioxide or propane, A motor-operated valve characterized in that the refrigerating machine oil flowing together with the natural refrigerant contains polyol ester, polyalkylene glycol or polyvinyl ether as a main component.

2. the drive mechanism includes 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 screwed, the magnet rotor is connected to the drive shaft via the reduction mechanism, When the magnet rotor rotates, the drive shaft rotates and moves axially, the valve element moves in the axial direction in accordance with the movement of the drive shaft, 2. The motor-operated valve according to claim 1, wherein the driving shaft, the bearing member, and the gear are the sliding parts.

3. the drive mechanism includes a magnet rotor, a reduction mechanism having a gear, and a drive shaft; the valve element is a rotary valve element connected to the drive shaft, the magnet rotor is connected to the drive shaft via the reduction mechanism, When the magnet rotor rotates, the drive shaft and the rotary valve element rotate, The motor-operated valve according to claim 1 , wherein the gear is the sliding part.

4. the drive mechanism includes a magnet rotor, a male screw member having a male screw, and a female screw member having a female screw that is screwed with the male screw, When one of the male screw member and the female screw member is a first member and the other is a 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 element moves in the axial direction in accordance with the movement of the first member relative to the second member, The motor-operated 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 motor-operated valve includes a valve body having a valve element, a valve chamber, a drive mechanism for driving the valve element, and a case in which the drive mechanism is disposed, The case has a cylindrical shape, one end is open and the other end is closed, One end of the case is joined to the valve body, The natural refrigerant is introduced into the inside of the case, the drive mechanism has a sliding part; Fluorine grease is applied to the sliding parts, The base oil of the fluorine grease contains perfluoropolyether, chlorotrifluoroethylene or perfluoroalkyl ether as a main component, The natural refrigerant is mainly composed of carbon dioxide or propane, A refrigeration cycle device characterized in that the refrigerating machine oil flowing together with the natural refrigerant contains polyol ester, polyalkylene glycol or polyvinyl ether as a main component.

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