Valve devices and refrigeration cycle systems

Abstract

The present invention aims to provide a valve device and a refrigeration cycle system that reduce refrigerant passage noise in the micro-flow rate control range. [Solution] The valve device 1 comprises a valve port 14, a valve seat 15, a valve body 50, a drive unit 70, and a minute flow rate control area 80. One of the valve seat tapered portion 15a of the valve seat 15 and the valve body tapered portion 58 of the valve body 50 constitutes a mortar-shaped concave portion. The other of the valve seat tapered portion 15a and the valve body tapered portion 58 constitutes a frustoconical convex portion. At least a plurality of minute peaks 58b adjacent to the inclination direction of the valve body tapered portion 58 are formed on the surface of the convex portion. When the maximum height in the surface roughness of the concave portion is RzA and the maximum height of the convex portion is RzB, RzA

Description

Technical Field

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

Background Art

[0002] There is known a valve device having a structure for reducing refrigerant passage noise generated when refrigerant passes through (see, for example, Patent Document 1). As shown in FIG. 1 of Patent Document 1, the expansion valve (valve device) described in Patent Document 1 includes a valve body 1 having a valve chamber 12 and a valve hole 10 inside, and a valve body 13 that approaches or separates from the valve hole 10. A refrigerant passage 4 is formed between the outer peripheral surface of the valve body 13 and the inner peripheral surface of the valve chamber 12, and a throttle portion 5 with a variable opening is formed between the valve body 13 and the valve hole 10. The valve body 13 includes a cylindrical portion extending in the axial direction, and an uneven turbulence generating portion 6 is formed on the outer peripheral surface of the cylindrical portion. When refrigerant flows from the refrigerant passage 4 to the throttle portion 5, the flow of the refrigerant is disturbed by the turbulence generating portion 6, whereby the bubbles contained in the refrigerant are subdivided and homogenized, and the refrigerant passage noise derived from the bubbles is reduced.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in recent years, when a valve device is used in refrigeration and air-conditioning equipment, with the refinement of temperature control, minute flow control of refrigerant has been required. For this reason, high quietness is required in a minute flow control range where the opening degree of a valve port (valve hole 10 in Patent Document 1) becomes minute. However, in the expansion valve described in Patent Document 1, the throttle portion 5 itself does not have a structure for reducing refrigerant passage noise, and there is a problem in the noise reduction effect particularly when controlling a minute flow rate at the throttle portion 5.

[0005] An object of the present invention is to provide a valve device and a refrigeration cycle system in which the refrigerant passing sound in a minute flow rate control region is reduced.

Means for Solving the Problems

[0006] The valve device of the present invention includes a valve port through which a fluid passes, a metal valve seat having a valve seat taper portion formed of a tapered surface, a metal valve body having a valve body taper portion formed of a tapered surface that is close to or separated from the valve seat taper portion, a drive portion that drives the valve body, and a minute flow rate control region that is formed by a minute gap that is a variable predetermined gap generated between the valve seat taper portion and the valve body taper portion and that controls a minute flow rate of the fluid. The valve device is characterized in that one of the valve seat taper portion and the valve body taper portion constitutes a mortar-shaped concave portion, the other of the valve seat taper portion and the valve body taper portion constitutes a truncated cone-shaped convex portion, and on the surface of the convex portion, at least a plurality of minute ridges adjacent to the inclination direction from the base end side to the tip end side of the valve body taper portion are formed. When the maximum height in the surface roughness of the concave portion is RzA and the maximum height of the convex portion is RzB, RzA < RzB, and when the interval in the inclination direction between the adjacent minute ridges is LtB and the length in the inclination direction from the upper end to the lower end of the valve seat taper portion is LA, LtB < 1 / 2LA.

[0007] ​​​​​Also, at this time, it is preferable that 0.01 μm < RzA < 0.5 μm and 0.8 μm < RzB < 6.3 μm. According to such a configuration, stable flow control in the micro flow control region and reduction of refrigerant passing noise due to appropriate attenuation of the flow velocity of the refrigerant flowing through the micro flow control region can be better achieved simultaneously.

[0009] Also, it is preferable that 5 μm < LtB < 60 μm and 10 μm < LA < 150 μm. According to such a configuration, the refrigerant is meandered a plurality of times along the micro mountain portions formed on the surface of the convex-shaped portion and the valleys between the micro mountain portions, and stable flow control in the micro flow control region and reduction of refrigerant passing noise due to appropriate attenuation of the flow velocity of the refrigerant flowing through the micro flow control region can be better achieved simultaneously.

[0010] Also, it is preferable that 5 μm < LtB < 30 μm and 10 μm < LA < 75 μm. According to such a configuration, the meandering of the refrigerant is made even more likely to occur, and stable flow control in the micro flow control region and reduction of refrigerant passing noise due to appropriate attenuation of the flow velocity of the refrigerant flowing through the micro flow control region can be better achieved simultaneously.

[0011] Also, in the micro flow control region, the maximum dimension in the axial direction is preferably 35 μm or less. According to such a configuration, for example, even in a very minute micro flow control region immediately after the valve body separates from the valve seat, the refrigerant is meandered a plurality of times along the micro mountain portions and the valleys between the micro mountain portions, and stable flow control and reduction of refrigerant passing noise due to appropriate attenuation of the flow velocity of the refrigerant can be better achieved simultaneously. Note that the maximum dimension in the axial direction of this micro flow control region may be adjusted to be the value immediately after the valve body separates, considering, for example, the number of pulses of the stepping motor that drives the valve body and the lift amount (movement amount) of the valve body.

[0012] Furthermore, in the aforementioned minute flow rate control region, the maximum dimension in the intersecting direction that crosses the axial direction is preferably 13 μm or less. With such a configuration, for example, even in the extremely minute minute flow rate control region immediately after the valve body leaves the valve seat, the refrigerant is made to meander multiple times along the minute peaks and valleys between the minute peaks, thereby better achieving both stable flow rate control and reduction of refrigerant passage noise due to appropriate attenuation of the refrigerant flow velocity. Note that the maximum dimension in the intersecting direction of this minute flow rate control region may be adjusted to be the value immediately after the valve body leaves the seat, taking into consideration, for example, the number of pulses of the stepping motor that drives the valve body, the amount of lift (movement) of the valve body, and the shape of the valve body tip and valve seat.

[0013] Furthermore, the refrigeration cycle system of the present invention is a refrigeration cycle system including a compressor, a condenser, an expansion valve, and an evaporator, characterized in that any of the valve devices described above is used as the expansion valve. According to the present invention, a refrigeration cycle system can be configured using a valve device that reduces refrigerant passage noise in the minute flow rate control range. [Effects of the Invention]

[0014] According to the present invention, it is possible to provide a valve device and a refrigeration cycle system that reduce refrigerant passage noise in the minute flow rate control range. [Brief explanation of the drawing]

[0015] [Figure 1] A cross-sectional view of a valve device according to one embodiment of the present invention, cut along axis L. [Figure 2] Enlarged cross-sectional view of region A in Figure 1. [Figure 3] Enlarged cross-sectional view of region B in Figure 2. [Figure 4] Enlarged view of the main part in Figure 3. [Figure 5] A diagram showing an example of the refrigeration cycle system of the present invention. [Figure 6] A graph showing the noise reduction value and flow rate change rate when the valve port diameter is 2.2Φ. [Figure 7]Graph showing the noise reduction value and flow rate change rate when the diameter of the valve port is 3.4Φ. [Figure 8] Graph showing the noise reduction value and flow rate change rate when the diameter of the valve port is 4.2Φ. [Figure 9] Graph showing the noise reduction value and flow rate change rate when the diameter of the valve port is 8.0Φ. [Figure 10] Graph showing the noise reduction value and flow rate change rate when the diameter of the valve port is 9.0Φ.

Mode for Carrying Out the Invention

[0016] Hereinafter, embodiments of the present invention will be described based on FIGS. 1 to 10. The valve device 1 according to this embodiment is an electric valve that constitutes a part of, for example, a refrigeration cycle system (see FIG. 5), and controls the flow of refrigerant (fluid). This valve device 1 is particularly used in the field of refrigeration and air-conditioning equipment that requires precise control of the refrigerant flow rate. In the following description, the direction along the axis L of the valve housing 10 described later is referred to as the "axis L direction", one side in the axis L direction is referred to as "one side L1", and the other side is referred to as "the other side L2". Also, the direction orthogonal to the axis L is referred to as the "intersection direction X". These direction definitions are for the convenience of explanation only and do not limit the directions in the actual use state of the valve device 1. In addition, in FIG. 3, for the sake of simplifying the figure, the hatchings of the valve body 50 and the valve seat 15 are omitted.

[0017] As shown in Fig. 1, the valve device 1 includes a valve housing 10, a guide member 40, a valve body 50, and a drive unit 70. The valve housing 10 is formed in a substantially bottomed cylindrical shape using a metal material such as brass or stainless steel, and has a valve chamber 11 inside. A first port 12 penetrating in the plate thickness direction is formed in the side wall of the valve housing 10, and a first joint pipe 13 as a fluid pipe is inserted into the first port 12. The first joint pipe 13 is fixed to the valve housing 10 by brazing or the like, and its inside communicates with the valve chamber 11 through the first port 12. A valve port 14 penetrating in the direction of the axis L is formed at the center of the bottom wall of the valve housing 10, and fluid passes through the valve port 1,4. As shown in Fig. 2, the valve port 14 includes a small-diameter portion 14a opening to one side L1 and a large-diameter portion 14b opening to the other side L2 continuously with the small-diameter portion 14a. As shown in Fig. 3, the end of the one side L1 of the small-diameter portion 14a is processed to be a valve seat 15 where the valve body 50 approaches or separates.

[0018] The surface of the valve seat 15 is the valve seat tapered portion 15a in the present invention. The valve seat tapered portion 15a is a tapered surface inclined so as to approach toward the other side L2 with respect to the axis L, and constitutes a mortar-shaped concave portion as a part of the valve seat 15. In this embodiment, the valve seat 15 is formed integrally with the metal valve housing 10, but not limited thereto, an annular valve seat 15 may be formed using a metal material, the valve seat tapered portion 15a may be formed on the valve seat 15, and this may be connected to the valve housing 10. As shown in Fig. 1, a small-diameter cylindrical portion 16 protruding toward the other side L2 is formed at the lower end of the bottom wall of the valve housing 10. The inside of the small-diameter cylindrical portion 16 constitutes a second port 17 communicating with the valve port 14. A second joint pipe 18 as a fluid pipe is inserted into the inner peripheral surface of the small-diameter cylindrical portion 16, and the second joint pipe 18 is fixed to the valve housing 10 by brazing or the like. The inside of the second joint pipe 18 communicates with the valve chamber 11 through the second port 17 and the valve port 14. <000009-7> A rotor case 19, formed in a bottomed cylindrical shape from a metal material, is airtightly fixed to the upper end of the valve housing 10 by welding or the like at its open end edge. A second case 20 is fixed to the inner surface of one end L1 of the rotor case 19. The second case 20 has a cylindrical portion 21 that extends to the other side L2 along the axis L, and a cylindrical shaft guide 22, which guides the drive shaft 74 (described later) in the direction of the axis L, is inserted inside it. A rotation stopper mechanism 30 that restricts the rotation of the magnet rotor 72 (described later) is provided on the outer circumferential surface of the cylindrical portion 21.

[0020] The rotation stopper mechanism 30 comprises a spiral guide 31 wound around the outer circumferential surface of the cylindrical portion 21, and a coil-shaped slider 32 installed on the guide 31. The slider 32 has a claw portion 32a that protrudes outward in the intersecting direction X, and the claw portion 32a abuts against a ridge 73 formed on the inner circumferential surface of the magnet rotor 72. The slider 32 moves in the direction of the axis L while rotating around the axis L between a first stopper (not shown) provided on one side L1 of the guide 31 and a second stopper (not shown) provided on the other side L2 of the guide 31. Inside the sealed area between the valve housing 10 and the rotor case 19, a guide member 40 is installed.

[0021] The guide member 40 includes a cylindrical press-fit portion 41 formed from a resin material such as PPS (polyphenylene sulfide) or PEEK (polyetheretherketone). The press-fit portion 41 is press-fitted into an opening L1 on one side of the valve housing 10. Guide bodies 42 extending in the axial direction L are formed on both the one side L1 and the other side L2 of the press-fit portion 41. The guide bodies 42 are formed in a cylindrical shape with a smaller diameter than the press-fit portion 41 and extend in the axial direction L. A valve body guide hole 43 opening to the other side L2 is formed inside the guide body 42. The outer surface of the valve body 50 can slide against the inner surface of the valve body guide hole 43. An axial guide hole 44 is formed on one side L1 of the valve body guide hole 43, communicating with the valve body guide hole 43 and opening to the one side L1. The shaft guide hole 44 has a smaller diameter than the valve body guide hole 43, and an internal thread 45 is formed on its inner circumferential surface. The internal thread 45 is screwed onto an external thread 75 formed on the outer circumferential surface of the drive shaft 74, thereby screwing the drive shaft 74 in the axial direction L.

[0022] The valve body 50 is a component that is positioned close to or separated from the valve seat 15, and includes a holder portion 51 formed in a bottomed cylindrical shape using a metal material such as brass or stainless steel. A connecting hole 51a is formed at the bottom of the holder portion 51, penetrating in the axial direction L, and the other end L2 of the drive shaft 74 is inserted through the connecting hole 51a. The outer circumferential surface of the holder portion 51 faces the inner circumferential surface of the valve body guide hole 43 with a slight gap between them in the intersecting direction X, and is capable of sliding contact with the inner circumferential surface of the valve body guide hole 43. A needle member 52, formed by machining a metal material, is attached to the other end L2 of the holder portion 51.

[0023] As shown in Figure 2, the needle member 52 includes a mounting portion 53 that is press-fitted into the end opening of the other side L2 of the holder portion 51, a cylindrical portion 54 that extends from the center of the mounting portion 53 along the axis L to the other side L2, a tapered first tapered portion 55 that is continuous with the cylindrical portion 54, a tapered second tapered portion 56 that is formed on the other side L2 from the first tapered portion 55, and a leading edge portion 57 that is continuous with the second tapered portion 56. In the needle member 52, a valve body tapered portion 58, which is composed of a tapered surface, is formed between the first tapered portion 55 and the second tapered portion 56, as shown in Figure 3. The valve body tapered portion 58 is a surface that is close to or far from the valve seat tapered portion 15a, is inclined to approach the other side L2 with respect to the axis L, and forms a frustoconical convex portion in part of the valve body 50.

[0024] As shown in Figure 3, the length of the valve body tapered portion 58 in the inclined direction along the inclined surface from one side L1 to the other side L2 is set to be considerably larger than the length of the valve seat tapered portion 15a of the valve seat 15 in the inclined direction from one side L1 to the other side L2. As shown in Figure 1, a columnar spring receiver 59 extending in the axial direction L is arranged inside the holder portion 51, and a spring 60 is installed between the spring receiver 59 and the needle member 52. Due to the installation of the spring 60, the holder portion 51 is biased toward the other side L2 where the valve port 14 and valve seat 15 are located. The valve body 50 thus formed is driven by the drive unit 70 to move in the axial direction L.

[0025] The drive unit 70 is the part that drives the valve body 50 and includes a stepping motor 71. The stepping motor 71 includes a stator coil (not shown) located outside the rotor case 19, a magnet rotor 72 located inside the rotor case 19 surrounded by the stator coil, and other components such as a yoke and exterior members (not shown). The stator coil is connected to a control unit (not shown) and receives pulses from the control unit to rotate the magnet rotor 72 clockwise or counterclockwise around the axis L by a predetermined rotation angle corresponding to the pulse. The magnet rotor 72 is formed into a cylindrical shape by molding a base material mixed with magnetic powder. On the inner circumferential surface of one side L1 portion of the magnet rotor 72, a ridge 73 is formed that protrudes in the intersecting direction X and extends in the direction of the axis L. When the magnet rotor 72 rotates, the ridge 73 contacts the claw portion 32a of the slider 32 described above, transmitting the rotational force of the magnet rotor 72 to the slider 32.

[0026] In this configuration, when the magnet rotor 72 rotates, its rotational force is transmitted to the slider 32 via the claw portion 32a of the slider 32, causing the slider 32 to rotate. The rotation of the slider 32 stops when the claw portion 32a comes into contact with the first stopper or second stopper (not shown) as described above. When the rotation of the slider 32 stops, the rotation of the magnet rotor 72 is restricted. The magnet rotor 72 whose rotation is restricted by the first stopper is restricted from being displaced to one side L1, and the magnet rotor 72 whose rotation is restricted by the second stopper is restricted from being displaced to the other side L2. In other words, the uppermost and lowermost positions of the magnet rotor 72 are defined by the first and second stoppers.

[0027] A drive shaft 74 extending in the axial direction L is integrally molded at the center of the magnet rotor 72. The drive shaft 74 is rotatable and movable in the axial direction L together with the magnet rotor 72. Note that the drive shaft 74 does not necessarily need to be integrally molded with the magnet rotor 72; for example, it may be connected to the magnet rotor 72 via a bush or the like. A male thread 75 that screws into a female thread 45 is formed on the outer circumferential surface of the drive shaft 74, and together with the female thread 45, constitutes a screw feeding mechanism. A flange 76 with an outer diameter larger than the inner diameter of the connection hole 51a of the holder portion 51 described above is formed on the other side L2 of the drive shaft 74. The flange 76 is located inside the holder portion 51 and prevents the drive shaft 74 from coming out of the holder portion 51 on one side L1.

[0028] The valve device 1 of this embodiment, configured as described above, is used, for example, as an electronic expansion valve 100 (electric valve, expansion valve) in the field of refrigeration and air conditioning equipment, and constitutes part of a refrigeration cycle system. Figure 5 shows an example of a refrigeration cycle system of the present invention. In Figure 5, reference numeral 200 denotes an outdoor heat exchanger mounted on an outdoor unit, reference numeral 300 denotes an indoor heat exchanger mounted on an indoor unit, reference numeral 400 denotes a flow path switching valve that constitutes a four-way valve, and reference numeral 500 denotes a compressor. The electronic expansion valve 100, outdoor heat exchanger 200, indoor heat exchanger 300, flow path switching valve 400, and compressor 500 are connected by conduits as shown in the figure, and constitute a heat pump type refrigeration cycle system. Accumulators, pressure sensors, temperature sensors, etc. are omitted from the illustration.

[0029] The flow path of the refrigeration cycle system can be switched between two paths by the flow path switching valve 400: one for cooling operation and one for heating operation. During cooling operation, as shown by the solid arrows in Figure 5, the refrigerant compressed by the compressor 500 flows from the flow path switching valve 400 into the outdoor heat exchanger 200. At this time, the outdoor heat exchanger 200 functions as a condenser, and the liquid refrigerant flowing out of the outdoor heat exchanger 200 flows into the indoor heat exchanger 300 via the electronic expansion valve 100. At this time, the indoor heat exchanger 300 functions as an evaporator.

[0030] On the other hand, during heating operation, as shown by the dashed arrows in Figure 5, the refrigerant compressed by the compressor 500 circulates in the following order from the flow path switching valve 400 to the indoor heat exchanger 300, the electronic expansion valve 100, the outdoor heat exchanger 200, and then back to the compressor 500. The indoor heat exchanger 300 functions as a condenser, and the outdoor heat exchanger 200 functions as an evaporator.

[0031] The expansion valve 100 depressurizes and expands the liquid refrigerant flowing in from the outdoor heat exchanger 200 during cooling operation, or from the indoor heat exchanger 300 during heating operation, and also controls the flow rate of the refrigerant. In Figure 5, the electronic expansion valve 100 is installed in the refrigeration cycle system so that liquid refrigerant flows from the outdoor heat exchanger 200 into the first joint pipe 13 during cooling operation, and liquid refrigerant from the indoor heat exchanger 300 flows into the second joint pipe 18 during heating operation. However, the system is not limited to this configuration, and the electronic expansion valve 100 may also be installed in the refrigeration cycle system so that liquid refrigerant flows from the outdoor heat exchanger 200 into the second joint pipe 18 during cooling operation, and liquid refrigerant flows from the indoor heat exchanger 300 into the first joint pipe 13 during heating operation.

[0032] Next, the operation of the valve device 1 will be described. The valve device 1 switches between a fully closed state (not shown), a minute flow rate control state (shown in Figure 3), and a fully open state (not shown) by the drive unit 70. In the fully closed state, the valve body 50 is seated on the valve seat 15 (closest to it), and the flow rate of the refrigerant (fluid) becomes 0. When the stepping motor 71 is driven from this state, the magnet rotor 72 and drive shaft 74 rotate, and the screw feed mechanism between the male screw 75 and the female screw 45 moves the magnet rotor 72 and drive shaft 74 to one side L1 in the direction of the axis L. In conjunction with this movement, the valve body 50 rises, and the valve port 14 opens. As a result, the refrigerant flows between the first joint pipe 13, the first port 12, the valve chamber 11, the valve port 14, the second port 17, and the second joint pipe 18.

[0033] As shown in Figure 3, immediately after valve opening, the valve seat tapered portion 15a of the valve seat 15 and the valve body tapered portion 58 of the valve body 50 face each other in the intersecting direction X, creating a minute gap S of a variable predetermined interval between them. When fluid flows through this minute gap S, the flow rate is precisely controlled according to the size of the minute gap S, so the minute gap S constitutes a minute flow rate control region 80 that performs minute flow rate control of the refrigerant. The state in which the refrigerant flows through this minute flow rate control region 80 is called the minute flow rate control state. The specific size of the minute flow rate control region 80 can be appropriately selected considering the amount of pulses applied to the stepping motor 71 and the amount of lift of the valve body 50 corresponding to those pulses. However, from the viewpoint of fully demonstrating the sound-dampening effect of the minute peak portion 58b of the valve body 50, which will be described later, it is preferable that, for example, the size of the minute flow rate control region 80 has a maximum dimension S1 in the axial direction L of 35 μm or less and a maximum dimension S2 in the intersecting direction X of 13 μm or less. In this embodiment, when approximately 5 to 6 pulses are applied to the stepping motor 71, the maximum dimension S1 becomes 35 μm and the maximum dimension S2 becomes 13 μm.

[0034] After the minute flow rate control state, as the lift amount of the valve body 50 increases, the opposing points in the intersecting direction X of the valve seat tapered portion 15a change to the second tapered portion 56 and the outermost portion 57, and the gap between the valve seat 15 and the valve body 50 increases, so the flow rate of refrigerant flowing through the valve port 14 increases. When the entire needle member 52 has come out of the valve port 14, it enters a fully open state (not shown). At this time, the flow rate of refrigerant flowing through the valve port 14 is at its maximum. In this way, the valve device 1 controls the flow rate of refrigerant.

[0035] Here, in the valve device 1 that constitutes the refrigeration cycle system as in the present embodiment, the refrigerant passing sound when the refrigerant passes through may be a problem, and its reduction is required. In particular, in recent years, when the valve device 1 is used in refrigeration and air-conditioning equipment, with the refinement of temperature control, minute flow rate control of the refrigerant is performed, so high quietness is required in the minute flow rate control state. Therefore, in the present embodiment, in order to reduce the refrigerant passing sound in the minute flow rate control state, the surface structures of the valve seat taper portion 15a and the valve body taper portion 58 are devised. As shown in FIG. 3, on the valve body taper portion 58 of the valve body 50, minute concavo-convex shapes that are arranged or continuous concentrically or spirally around the axis L are formed by cutting. Of these concavo-convex shapes, the concave is a minute valley portion 58a, and the convex is a minute peak portion 58b.

[0036] As shown in FIG. 4, a plurality of minute valley portions 58a and minute peak portions 58b are arranged adjacent to each other in the inclination direction from the end portion (base end side) on one side L1 to the end portion (tip side) on the other side L2 of at least the valve body taper portion 58. Also, although not visible in FIG. 4, concavo-convex shapes after processing are also formed on the valve seat taper portion 15a. And, "maximum height RzB", which is one of the parameters of the surface property (surface roughness, JIS B 0601: 2013) of the valve body taper portion 58, is larger compared to "maximum height RzA (not shown)" of the valve seat taper portion 15a. That is, when the maximum height of the valve seat taper portion 15a (concave-shaped portion) is "maximum height RzA" and the maximum height of the valve body taper portion 58 (convex-shaped portion) is "maximum height RzB", RzA < RzB. By doing so, the refrigerant passing through the minute flow rate control region 80 travels in a meandering manner along the minute peak portion 58b and the minute valley portion 58a while heading toward the other side L2 along the valve seat taper portion 15a.

[0037] By the meandering of the refrigerant, the flow velocity of the refrigerant can be attenuated, and the refrigerant passing sound can be reduced. Here, from the viewpoint of appropriately attenuating the flow velocity of the refrigerant, it is preferable to adjust the maximum height RzA within the range of 0.01 μm < RzA < 0.5 μm, and it is preferable to adjust the maximum height RzB within the range of 0.8 μm < RzB < 6.3 μm. Further, as shown in FIG. 3, when the length in the inclination direction from one side L1 (upper end) to the other side L2 (lower end) of the valve seat tapered portion 15a is defined as "length LA", and in the valve body tapered portion 58, the interval in the inclination direction between adjacent minute mountain portions 58b is defined as "interval LtB", it is preferable that LtB < 1 / 2LA. Further, it is more preferable that "length LA" and "interval LtB" satisfy the conditions of 5 μm < LtB < 60 μm and 10 μm < LA < 150 μm, and it is even more preferable that 5 μm < LtB < 30 μm and 10 μm < LA < 75 μm. By doing so, the refrigerant passing through the minute flow rate control region 80 meanders a plurality of times (at least two or more times) along the minute mountain portions 58b and minute valley portions 58a. Then, by this meandering, the flow velocity of the refrigerant passing through the minute flow rate control region 80 can be appropriately attenuated, and the refrigerant passing sound can be reduced.

[0038] The valve body tapered portion 58 having the surface properties as described above can be formed by forming, for example, concentric or spiral minute valley portions 58a and minute mountain portions 58b around the axis L on the outer peripheral surface of the needle member 52 by cutting or the like. Further, the valve seat tapered portion 15a can be formed by performing precise cutting or the like on the upper end portion of the valve port 14.

[0039] Next, based on FIGS. 6 to 10, actual measurement examples of the noise and flow rate in the minute flow rate control state of the valve device 1 will be described. In this actual measurement example, the operating conditions of the valve device 1 were set as follows. First, the pressure P1 in the first joint pipe 13 was set to 2.0 to 3.0 MPa (megapascal), and the pressure difference ΔP between the inside of the first joint pipe 13 and the inside of the second joint pipe 18 was set to 0.05 MPa or less. Further, the inner diameter of the small diameter portion 14a in the valve port 14 was set to any one of 2.2Φ, 3.4Φ, 4.2Φ, 8.0Φ, and 9.0Φ. Further, the refrigerant was set to flow from the first joint pipe 13 side to the second joint pipe 18 side.

[0040] Figure 6 shows the relationship between "LtB / LA", which is the ratio of "interval LtB" to "length LA", "noise reduction value (dB(A))", and "flow rate change rate (%)" for a valve device 1 with a small diameter section 14a of 2.2Φ. The "noise reduction value" is the difference from the reference value of the noise (dB(A)) in a minute flow rate control state for a valve device that is structurally the same as the valve device 1 of this embodiment except that the surface properties of the valve seat tapered section 15a and the valve body tapered section 58 are different (no special processing is performed). The "flow rate change rate" is the percentage of the deviation between the actual flow rate at the valve port 14 and the design value of the flow rate at the valve port 14, when the lift amount of the valve body 50 and the opening degree of the valve port 14 are set to a predetermined size in a minute flow rate control state.

[0041] As shown in Figure 6, when LtB / LA = 1 / 30 (leftmost point ●), the "noise reduction value" was approximately -1.1 (dB(A)). In contrast, when LtB / LA = 1 / 15 (third point from the left ●), the "noise reduction value" was approximately -2.9 (dB(A)). In other words, the noise was reduced more when LtB / LA = 1 / 15 than when LtB / LA = 1 / 30. On the other hand, even when the value of LtB / LA was increased to more than 1 / 15, such as LtB / LA = 1 / 2 (third point from the right ●) or LtB / LA = 3 / 4 (rightmost point ●), the "noise reduction value" did not significantly exceed -2.9 (dB(A)). On the other hand, as the LtB / LA value was gradually increased, the "rate of change in flow rate" became approximately 1% up to LtB / LA = 1 / 2 (third point from the right ◇), and the flow rate at valve port 14 did not deviate significantly from the design value.

[0042] However, when LtB / LA is greater than 1 / 2 (for example, LtB / LA = 2 / 3 (the second point ◇ from the right) or LtB / LA = 3 / 4 (the rightmost point ◇)), the flow rate change rate becomes about 3 - 5%, and a deviation from the design value is observed in the flow rate at the valve port 14. The above tendency was the same even when the diameter of the small-diameter portion 14a was different. Fig. 7 shows the relationship between "LtB / LA", "noise reduction value (dB(A))", and "flow rate change rate (%)" for the valve device 1 with a small-diameter portion 14a having a diameter of 3.4Φ. Fig. 8 shows the relationship between "LtB / LA", "noise reduction value (dB(A))", and "flow rate change rate (%)" for the valve device 1 with a small-diameter portion 14a having a diameter of 4.2Φ. Fig. 9 shows the relationship between "LtB / LA", "noise reduction value (dB(A))", and "flow rate change rate (%)" for the valve device 1 with a small-diameter portion 14a having a diameter of 8.0Φ. Fig. 10 shows the relationship between "LtB / LA", "noise reduction value (dB(A))", and "flow rate change rate (%)" for the valve device 1 with a small-diameter portion 14a having a diameter of 9.0Φ.

[0043] In any of Figs. 7 to 10, when LtB / LA > 1 / 15 (the third point ● from the left), the "noise reduction value" becomes about -2.8 (dB(A)), showing a significant improvement, and even when LtB / LA is increased, it does not change significantly further. And the "flow rate change rate" is about 1% until LtB / LA = 1 / 2 (the third point ◇ from the right), and there is no significant deviation in the actual flow rate at the valve port 14 compared with the design value. However, when LtB / LA is greater than 1 / 2 (for example, LtB / LA = 2 / 3 (the second point ◇ from the right) or LtB / LA = 3 / 4 (the rightmost point ◇)), the flow rate change rate becomes about 3 - 5%, and a deviation from the design value is observed in the flow rate at the valve port 14. From the above results, from the perspective of appropriately reducing noise within the range where the flow rate does not deviate from the design value and does not significantly affect flow control, it is more preferable to set "length LA" and "interval LtB" within the management range of 1 / 15 < LtB / LA < 1 / 2.

[0044] According to the above-described embodiments, regarding the surface roughness, the maximum height RzA of the valve seat taper portion 15a (concave-shaped portion) < the maximum height RzB of the valve body taper portion 58 (convex-shaped portion), and the refrigerant (fluid) passing through the minute flow rate control region 80 controlled in this way will meander a plurality of times (at least two or more times) along the minute ridges 58b and minute valleys 58a formed on the surface of the valve body taper portion 58 while flowing in the inclined direction for the length LA of the valve seat taper portion 15a during passage. And, by this meandering, the flow velocity of the fluid passing through the minute flow rate control region 80 can be attenuated, and the refrigerant passage sound can be reduced. Therefore, it is possible to provide the valve device 1 in which the refrigerant passage sound in the minute flow rate control region 80 is reduced.

[0045] Also, regarding the "maximum height RzA" and the "maximum height RzB", by setting 0.01 μm < RzA < 0.5 μm and 0.8 μm < RzB < 6.3 μm, stable flow rate control in the minute flow rate control region 80 and reduction of the refrigerant passage sound by appropriate attenuation of the flow velocity of the refrigerant flowing through the minute flow rate control region 80 can be better achieved simultaneously.

[0046] Also, regarding the "interval LtB" and the "length LA", by setting 5 μm < LtB < 60 μm and 10 μm < LA < 150 μm, the refrigerant is meandered a plurality of times along the minute ridges 58b and minute valleys 58a formed on the surface of the valve body taper portion 58, and stable flow rate control in the minute flow rate control region 80 and reduction of the refrigerant passage sound by appropriate attenuation of the flow velocity of the refrigerant flowing through the minute flow rate control region 80 can be better achieved simultaneously.

[0047] Also, regarding the "interval LtB" and the "length LA", by setting 5 μm < LtB < 30 μm and 10 μm < LA < 75 μm, the meandering of the refrigerant is made more likely to occur, and stable flow rate control in the minute flow rate control region 80 and reduction of the refrigerant passage sound by appropriate attenuation of the flow velocity of the refrigerant flowing through the minute flow rate control region 80 can be better achieved simultaneously.

[0048] Furthermore, in the minute flow rate control region 80, by setting the maximum dimension in the axial L direction to 35 μm or less and the maximum dimension in the intersecting X direction to 13 μm or less, for example, even in the extremely minute minute flow rate control region 80 immediately after the valve body 50 has left the valve seat 15, the refrigerant can meander multiple times along the minute peaks 58b and minute valleys 58a, thereby better achieving both stable flow rate control and reduction of refrigerant passage noise through appropriate attenuation of the refrigerant flow velocity. Note that the maximum dimension in the axial L direction of this minute flow rate control region 80 may be adjusted to the value immediately after the valve body 50 has left the seat, for example, by considering the number of pulses of the stepping motor 71 that drives the valve body 50 and the lift amount (movement amount) of the valve body 50.

[0049] Furthermore, according to the above embodiment, a refrigeration cycle system can be configured using an electronic expansion valve 100 (electric valve, expansion valve), which is a valve device 1 that reduces refrigerant passage noise in the minute flow rate control range 80.

[0050] Although embodiments of the present invention have been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments, and any design changes, etc., that do not depart from the spirit of the present invention are also included. For example, in this embodiment, an electric valve in which the valve body 50 is driven by a stepping motor 71 is given as an example of a valve device 1. However, the valve device 1 is not limited to this, and may be a manual valve in which the valve body is manually driven, or a solenoid-driven electromagnetic valve, etc. Furthermore, even in the case of an electric valve, the drive unit is not limited to a stepping motor, but may be another motor.

[0051] Furthermore, in this embodiment, a convex portion is formed on the valve body 50 side and a concave portion is formed on the valve seat 15 side. However, the configuration is not limited to this, and a columnar member extending in the axial direction L is placed at the center of the valve port 14, and a valve seat is formed at its end on the valve chamber 11 side, and a cylindrical valve body is provided that surrounds the valve seat and can move closer to or further away from the valve seat. Then, a convex portion may be formed on the part of the valve seat that is close to the valve body, and a concave portion may be formed on the part of the valve body that is close to the valve seat. That is, one of the valve seat tapered portion 15a and the valve body tapered portion 57 may constitute a mortar-shaped concave portion, and the other of the valve seat tapered portion 15a and the valve body tapered portion 57 may constitute a frustoconical convex portion. [Explanation of Symbols]

[0052] LA length LtB interval RzA Maximum Height RzB Maximum Height S tiny gap 1 Valve device 14 valve ports 15 valve seats 15a Valve seat tapered portion (concave shape portion) 50 valve bodies 58 Valve body tapered section (convex shape section) 58b Micro-mountain section 70 Drive unit 80 Micro-flow control range

Claims

1. A valve device comprising: a valve port through which a fluid passes; a metal valve seat having a tapered valve seat portion formed by a tapered surface; a metal valve body having a tapered valve body portion formed by a tapered surface that is adjacent to or separated from the tapered valve seat portion; a drive unit for driving the valve body; and a minute flow control region which is a minute gap of a variable predetermined interval between the tapered valve seat portion and the tapered valve body portion and is used for minute flow control of the fluid, One of the valve seat tapered portion and the valve body tapered portion constitutes a mortar-shaped concave portion. The other of the valve seat tapered portion and the valve body tapered portion constitutes a frustoconical convex portion. On the surface of the convex portion, at least a plurality of adjacent minute peaks are formed in the direction of inclination from the base end to the tip of the valve body tapered portion. When the maximum height of the surface roughness of the concave portion is RzA and the maximum height of the convex portion is RzB, then RzA < RzB, A valve device characterized in that, when LtB is the distance between adjacent minute peaks in the inclination direction, and LA is the length in the inclination direction from the upper end to the lower end of the valve seat tapered portion, LtB < 1 / 2LA.

2. 0.01 μm < RzA < 0.5 μm, The valve device according to claim 1, characterized in that 0.8 μm < RzB < 6.3 μm.

3. The valve device according to claim 1, characterized in that 5 μm < LtB < 60 μm and 10 μm < LA < 150 μm.

4. The valve device according to claim 1, characterized in that 5 μm < LtB < 30 μm and 10 μm < LA < 75 μm.

5. The valve device according to claim 1, characterized in that, in the aforementioned minute flow rate control region, the maximum dimension in the axial direction is 35 μm or less.

6. The valve device according to claim 1, characterized in that, in the minute flow rate control region, the maximum dimension in the intersecting direction that crosses the axial direction is 13 μm or less.

7. A refrigeration cycle system comprising a compressor, a condenser, an expansion valve, and an evaporator, characterized in that the valve device described in any one of claims 1 to 6 is used as the expansion valve.

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