Valve device and refrigeration cycle system

Abstract

The purpose of the present invention is to provide a valve device and a refrigeration cycle system that reduce the noise of refrigerant passage in a minute flow rate control region. A valve device (1) is provided with a valve port (14), a valve seat (15), a valve body (50), a drive unit (70), and a micro flow rate control region (80). One of a valve seat conical part (15a) of the valve seat and a valve core conical part (58) of the valve core forms a mortar-shaped concave part. The other of the valve seat tapered part and the valve core tapered part forms a convex part in the shape of a circular truncated cone. The surface of the convex part is provided with at least a plurality of tiny mountain parts (58b) which are adjacent to each other in the inclined direction of the valve core tapered part. When the maximum height of the surface roughness of the concave portion is RzA and the maximum height of the convex portion is RzB, RzA < RzB is satisfied. In addition, when the interval in the inclination direction of the adjacent minute mountain parts is set as LtB and the length in the inclination direction of the valve seat tapered part is set as LA, LtB < 1 / 2 LA.

Description

Technical Field

[0001] This invention relates to a valve device and a refrigeration circulation system. Background Technology

[0002] A valve device with a structure that reduces the noise generated when refrigerant passes through is known (for example, see Patent Document 1). As in Patent Document 1... Figure 1 As shown, the expansion valve (valve device) described in Patent Document 1 includes: a valve body 1, which internally has a valve chamber 12 and a valve orifice 10; and a valve core 13, which is close to or far from the valve orifice 10. A refrigerant passage 4 is formed between the outer peripheral surface of the valve core 13 and the inner peripheral surface of the valve chamber 12, and a throttling section 5 with a variable opening is formed between the valve core 13 and the valve orifice 10. The valve core 13 has a cylindrical portion extending along its axial direction, and a turbulence-generating portion 6 with irregular shapes is formed on the outer peripheral surface of the cylindrical portion. When the refrigerant flows from the refrigerant passage 4 to the throttling section 5, the flow of the refrigerant is disturbed by the turbulence-generating portion 6, thereby refining and homogenizing the bubbles contained in the refrigerant, and reducing the sound of the refrigerant from the bubbles.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2005-226846 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] However, in recent years, with the increasing precision of temperature control in the application of valve devices to refrigeration and air conditioning equipment, there is a demand for precise control of refrigerant flow. Therefore, high noise reduction is required in the micro-flow control region where the valve orifice (valve hole 10 in Patent Document 1) has a very small opening. However, in the expansion valve described in Patent Document 1, the throttling section 5 itself does not have a structure to reduce the noise of refrigerant passage, and there is a problem with noise reduction, especially when controlling a very small flow rate through the throttling section 5.

[0008] The purpose of this invention is to provide a valve device and a refrigeration cycle system that reduce refrigerant noise in a small flow control area.

[0009] Solution for solving the problem

[0010] The valve device of the present invention includes: a valve port through which a fluid passes; a metallic valve seat having a valve seat conical portion formed by a conical surface; a metallic valve element having a valve element conical portion formed by a conical surface that approaches or separates from the valve seat conical portion; a driving portion that drives the valve element; and a minute flow control region that is formed by a minute gap, which is a variable predetermined gap generated between the valve seat conical portion and the valve element conical portion, and performs minute flow control of the fluid. The valve device is characterized in that one of the valve seat conical portion and the valve element conical portion constitutes a mortar-shaped concave portion, and the other of the valve seat conical portion and the valve element conical portion constitutes a truncated cone-shaped convex portion. On the surface of the convex portion, at least a plurality of minute mountain portions adjacent to each other in an inclined direction from the base end side toward the front end side of the valve element conical portion are formed. When the maximum height of the surface roughness of the concave portion is set as RzA and the maximum height of the convex portion is set as RzB, RzA < RzB, and when the interval in the inclined direction between the adjacent minute mountain portions is set as LtB and the length in the inclined direction from the upper end to the lower end of the valve seat conical portion is set as LA, LtB < 1 / 2LA.

[0011] According to the present invention like this, by controlling the surface roughness such that the maximum height RzA of the concave portion < the maximum height RzB of the convex portion, during the period when the fluid in the minute flow control region flows along the inclined direction by an amount equal to the length LA of the valve seat conical portion, the fluid winds multiple times (at least two or more times) along the minute mountain portions and the valleys between the minute mountain portions formed on the surface of the convex portion. Thus, through this winding, the flow velocity of the fluid passing through the minute flow control region can be reduced, and the refrigerant passing sound can be reduced. Therefore, a valve device with reduced refrigerant passing sound in the minute flow control region can be provided.

[0012] In addition, at this time, it is preferable that 0.01μm < RzA < 0.5μm and 0.8μm < RzB < 6.3μm. According to such a structure, it is possible to better balance stable flow control in the minute flow control region and reduction of the refrigerant passing sound brought about by appropriate attenuation of the flow velocity of the refrigerant flowing in the minute flow control region.

[0013] In addition, it is preferable that 5μm < LtB < 60μm and 10μm < LA < 150μm. According to such a structure, by making the refrigerant wind multiple times along the minute mountain portions and the valleys between the minute mountain portions formed on the surface of the convex portion, it is possible to better balance stable flow control in the minute flow control region and reduction of the refrigerant passing sound brought about by appropriate attenuation of the flow velocity of the refrigerant flowing in the minute flow control region.

[0014] Furthermore, it is preferable that 5μm < LtB < 30μm, and 10μm < LA < 75μm. This structure facilitates refrigerant meandering, better balancing stable flow control in the micro-flow control region with appropriate reduction in refrigerant velocity within that region, thus reducing refrigerant noise.

[0015] Furthermore, it is preferable that the maximum dimension in the axial direction of the aforementioned micro-flow control region is 35 μm or less. With this structure, for example, even in the extremely small micro-flow control region immediately after the valve core leaves the valve seat, the refrigerant meanders multiple times along the small hills and valleys between them, better balancing stable flow control with appropriate reduction in refrigerant velocity and refrigerant noise. Moreover, the maximum dimension in the axial direction of this micro-flow control region can be adjusted, for example, by taking into account the number of pulses of the stepper motor driving the valve core and the amount of valve core lifting (movement), to achieve a value immediately after the valve core leaves the seat.

[0016] Furthermore, it is preferable that the maximum dimension of the intersection direction with the axial direction in the aforementioned micro-flow control region is 13 μm or less. With this structure, for example, even in the extremely small micro-flow control region immediately after the valve core leaves the valve seat, the refrigerant meanders multiple times along the small hills and valleys between them, better balancing stable flow control with appropriate reduction in refrigerant velocity and refrigerant noise. Moreover, the maximum dimension of the intersection direction in this micro-flow control region can be adjusted, for example, by taking into account the number of pulses of the stepper motor driving the valve core, the valve core's lifting amount (movement amount), and the shape of the valve core tip and valve seat, to achieve a value immediately after the valve core leaves the seat.

[0017] Furthermore, the refrigeration cycle system of the present invention includes a compressor, a condenser, an expansion valve, and an evaporator. The refrigeration cycle system is characterized in that the valve device described in any of the above-mentioned embodiments is used as the expansion valve. According to this invention, a refrigeration cycle system can be constructed using a valve device that reduces the noise level of a refrigerant within a small flow control range.

[0018] Invention Effects

[0019] According to the present invention, a valve device and a refrigeration cycle system that reduce refrigerant passage noise in a small flow control area can be provided. Attached Figure Description

[0020] Figure 1 This is a cross-sectional view of a valve device according to an embodiment of the present invention cut along axis L.

[0021] Figure 2 yes Figure 1An enlarged sectional view of region A.

[0022] Figure 3 yes Figure 2 An enlarged sectional view of region B.

[0023] Figure 4 yes Figure 3 Enlarged view of the main parts.

[0024] Figure 5 This is a diagram illustrating an example of the refrigeration cycle system of the present invention.

[0025] Figure 6 This is a graph showing the noise reduction and flow rate change when the valve port diameter is 2.2Φ.

[0026] Figure 7 This is a graph showing the noise reduction and flow rate change when the valve port diameter is 3.4Φ.

[0027] Figure 8 This is a graph showing the noise reduction and flow rate change when the valve port diameter is 4.2Φ.

[0028] Figure 9 This is a graph showing the noise reduction and flow rate change when the valve port diameter is 8.0Φ.

[0029] Figure 10 This is a graph showing the noise reduction and flow rate change when the valve port diameter is 9.0Φ.

[0030] In the picture:

[0031] LA—Length, LtB—Interval, RzA—Maximum height, RzB—Maximum height, S—Minimum gap, 1—Valve assembly, 14—Valve port, 15—Valve seat, 15a—Valve seat conical part (concave part), 50—Valve core, 58—Valve core conical part (convex part), 58b—Minimum hill, 70—Actuator, 80—Minimum flow control area. Detailed Implementation

[0032] The following is based on Figures 1-10 This invention describes an embodiment. The valve device 1 in this embodiment constitutes, for example, a refrigeration cycle system (see...). Figure 5This is an electric valve, part of the valve housing 10, that controls the flow of refrigerant (fluid). This valve device 1 is particularly useful in applications requiring precise refrigerant flow control, such as refrigeration and air conditioning equipment. Furthermore, in the following description, the direction along the axis L of the valve housing 10 will be referred to as "axis L direction," one side of the axis L direction will be referred to as "side L1," and the other side as "other side L2." Additionally, the direction orthogonal to the axis L will be referred to as "crossing direction X." These definitions are merely for ease of explanation and do not limit the actual operating conditions of the valve device 1. Furthermore, in... Figure 3 In order to simplify the diagram, the cross-sectional lines of valve core 50 and valve seat 15 have been omitted.

[0033] like Figure 1 As shown, the valve device 1 includes a valve housing 10, a guide member 40, a valve core 50, and a drive unit 70. The valve housing 10 is formed into a generally bottomed cylindrical shape using a metal material such as brass or stainless steel, and has a valve chamber 11 inside. A first port 12 extending along the thickness direction is formed on the side wall of the valve housing 10, and a first connector pipe 13 for fluid piping is inserted through the first port 12. The first connector pipe 13 is fixed to the valve housing 10 by brazing or the like, and its interior communicates with the valve chamber 11 via the first port 12. A valve port 14 extending along the axis L is formed in the center of the bottom wall of the valve housing 10, and fluid passes through the valve port 14. Figure 2 As shown, the valve port 14 has a small-diameter portion 14a that opens to one side L1 and a large-diameter portion 14b that is continuous with the small-diameter portion 14a and opens to the other side L2. Figure 3 As shown, the end of one side L1 of the small diameter portion 14a is machined to become the valve seat 15 near or away from the valve core 50.

[0034] The surface of the valve seat 15 is the valve seat tapered portion 15a of the present invention. The valve seat tapered portion 15a is a tapered surface that is inclined toward the axis L as it approaches the other side L2, and a portion of the valve seat 15 forms a mortar-shaped concave portion. Furthermore, in this embodiment, the valve seat 15 is integrally formed with the metal valve housing 10, but it is not limited to this; a ring-shaped valve seat 15 may also be formed using a metal material, with the valve seat tapered portion 15a formed on this valve seat 15, and connected to the valve housing 10. Figure 1 As shown, a small-diameter cylindrical portion 16 protruding to the other side L2 is formed at the lower end of the bottom wall of the valve body 10. The interior of the small-diameter cylindrical portion 16 forms a second port 17 that communicates with the valve port 14. A second connector pipe 18, serving as a fluid piping, is inserted through the inner circumferential surface of the small-diameter cylindrical portion 16, and the second connector pipe 18 is fixed to the valve body 10 by brazing or the like. The interior of the second connector pipe 18 communicates with the valve chamber 11 via the second port 17 and the valve port 14.

[0035] A rotor housing 19, made of metal and formed into a bottomed cylindrical shape, is hermetically fixed to the upper end of the valve housing 10 by welding or the like. A second housing 20 is fixed to the inner surface of one side L1 end of the rotor housing 19. The second housing 20 has a cylindrical portion 21 extending along the axis L to the other side L2, and a cylindrical shaft guide 22 that guides the drive shaft 74 (described later) along the axis L is inserted inside it. A rotation stop mechanism 30 is provided on the outer peripheral surface of the cylindrical portion 21 to limit the rotation of the magnetic rotor 72 (described later).

[0036] The rotary stop mechanism 30 includes a spiral guide 31 wound along the outer peripheral surface of the cylindrical portion 21 and a coil-shaped slider 32 disposed on the guide 31. A claw portion 32a protruding outward in the intersecting direction X is formed on the slider 32, and the claw portion 32a abuts against a protrusion 73 formed on the inner peripheral surface of the magnetic rotor 72. The slider 32 moves along the axis L while rotating about the axis L, between a first stop (not shown) disposed on one side L1 of the guide 31 and a second stop (not shown) disposed on the other side L2 of the guide 31. A guide member 40 is disposed inside the valve housing 10 and the rotor housing 19.

[0037] The guide member 40 has a cylindrical press-in portion 41 formed using a resin such as PPS (polyphenylene sulfide) or PEEK (polyether ether ketone). The press-in portion 41 is pressed into an opening on one side L1 of the valve housing 10. A guide body 42 extending along the axis L is formed on one side L1 and the other side L2 of the press-in portion 41. The guide body 42 is formed as a cylinder with a diameter smaller than that of the press-in portion 41 and extends along the axis L. A valve core guide hole 43 opening to the other side L2 is formed inside the guide body 42. The outer peripheral surface of the valve core 50 can slide in contact with the inner peripheral surface of the valve core guide hole 43. A shaft guide hole 44 communicating with the valve core guide hole 43 and opening to one side L1 is formed on one side L1 of the valve core guide hole 43. The diameter of the shaft guide hole 44 is smaller than that of the valve core guide hole 43, and an internal thread 45 is formed on its inner peripheral surface. The internal thread 45 is threadedly engaged with the external thread 75 formed on the outer peripheral surface of the drive shaft 74, thereby feeding the drive shaft 74 threadedly along the axis L.

[0038] The valve core 50 is a component located near or away from the valve seat 15, and includes a bottomed cylindrical support portion 51 formed from a metal material such as brass or stainless steel. A connecting hole 51a extending along the axis L is formed at the bottom of the support portion 51, and the end of the drive shaft 74 on the other side L2 is inserted into the connecting hole 51a. The outer peripheral surface of the support portion 51 is positioned slightly apart from the inner peripheral surface of the valve core guide hole 43 in the intersecting direction X, and is capable of sliding contact with the inner peripheral surface of the valve core guide hole 43. A needle component 52, formed by machining a metal material, is mounted at the end of the other side L2 of the support portion 51.

[0039] like Figure 2 As shown, the needle component 52 includes: a mounting portion 53, which is pressed into an end opening on the other side L2 of the support portion 51; a cylindrical portion 54 extending from the center of the mounting portion 53 along the axis L to the other side L2; a tapered first conical portion 55 continuous with the cylindrical portion 54; a tapered second conical portion 56 formed on the other side L2 than the first conical portion 55; and a foremost end portion 57 continuous with the second conical portion 56. In the needle component 52, as... Figure 3 As shown, a valve core cone portion 58, which is composed of a cone-shaped surface, is formed between the first cone portion 55 and the second cone portion 56. The valve core cone portion 58 is a surface that is close to or away from the valve seat cone portion 15a, and is inclined in a manner that it approaches the axis L as it moves toward the other side L2, and forms a convex truncated cone shape on a part of the valve core 50.

[0040] like Figure 3 As shown, the length of the valve core cone portion 58 along the inclined direction from one side L1 to the other side L2 is much larger than the length of the valve seat cone portion 15a of the valve seat 15 along the inclined direction from one side L1 to the other side L2. Figure 1 As shown, a columnar spring seat 59 extending along the axis L is disposed inside the support portion 51, and a spring 60 is provided between the spring seat 59 and the needle component 52. By providing the spring 60, the support portion 51 is subjected to force on the other side L2 where the valve port 14 and valve seat 15 are located. The valve core 50 thus formed is driven by the drive portion 70 to move along the axis L.

[0041] The drive unit 70 drives the valve core 50 and includes a stepper motor 71. The stepper motor 71 includes a stator coil (not shown) disposed outside the rotor housing 19, a magnetic rotor 72 disposed inside the rotor housing 19 in a position surrounded by the stator coil, and other components (not shown), such as a magnetic yoke and external parts. The stator coil is connected to a control unit (not shown) and receives pulses from the control unit, causing the magnetic rotor 72 to rotate to the right or left around the axis L by a predetermined rotation angle corresponding to the pulse. The magnetic rotor 72 is formed into a cylindrical shape by molding a base material mixed with magnetic powder. A protrusion 73 is formed on the inner circumferential surface of one side L1 portion of the magnetic rotor 72, protruding in the intersecting direction X and extending in the direction of the axis L. When the magnetic rotor 72 rotates, the protrusion 73 abuts against the claw portion 32a of the slider 32, transmitting the rotational force of the magnetic rotor 72 to the slider 32.

[0042] With this structure, when the magnetic rotor 72 rotates, its rotational force is transmitted to the slider 32 via the claw 32a, causing the slider 32 to rotate. The rotation of the slider 32 is stopped by the claw 32a contacting the first or second stop (not shown). When the rotation of the slider 32 stops, the rotation of the magnetic rotor 72 is restricted. Furthermore, the magnetic rotor 72, whose rotation is restricted by the first stop, is restricted to displace to one side L1, and the magnetic rotor 72, whose rotation is restricted by the second stop, is restricted to displace to the other side L2. That is, the uppermost and lowermost positions of the magnetic rotor 72 are defined by the first and second stops.

[0043] A drive shaft 74 extending along the axis L is integrally formed at the center of the magnetic rotor 72. The drive shaft 74 can rotate and move along the axis L together with the magnetic rotor 72. Alternatively, the drive shaft 74 does not necessarily need to be integrally formed with the magnetic rotor 72; for example, it can be connected to the magnetic rotor 72 via a bushing. An external thread 75 is formed on the outer peripheral surface of the drive shaft 74, which engages with the internal thread 45, forming a threaded feed mechanism together with the internal thread 45. A flange 76 is formed on the other side L2 of the drive shaft 74, and the flange 76 has an outer diameter larger than the inner diameter of the connecting hole 51a of the support portion 51. The flange 76 is disposed inside the support portion 51 to prevent the drive shaft 74 from disengaging from the support portion 51 to one side L1.

[0044] 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 forms part of the refrigeration cycle system. Figure 5 This is a diagram illustrating an example of the refrigeration cycle system of the present invention. Figure 5 In the diagram, symbol 200 represents the outdoor heat exchanger installed in the outdoor unit, symbol 300 represents the indoor heat exchanger installed in the indoor unit, symbol 400 represents the flow path switching valve constituting the four-way valve, and symbol 500 represents the compressor. The electronic expansion valve 100, outdoor heat exchanger 200, indoor heat exchanger 300, flow path switching valve 400, and compressor 500 are connected via conduits as shown in the diagram, forming a heat pump-type refrigeration cycle system. Furthermore, the liquid receiver, pressure sensor, temperature sensor, etc., are omitted from the diagram.

[0045] The flow path of the refrigeration cycle system is switched between two paths: the flow path during cooling operation and the flow path during heating operation, via the flow path switching valve 400. During cooling operation, such as... Figure 5As shown by the solid arrow, the refrigerant compressed by the compressor 500 flows into the outdoor heat exchanger 200 through the flow path switching valve 400. 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 through the electronic expansion valve 100. At this time, the indoor heat exchanger 300 functions as an evaporator.

[0046] On the other hand, during heating operation, such as Figure 5 As shown by the dashed arrow, the refrigerant compressed by the compressor 500 circulates through the flow path switching valve 400 in the order of indoor heat exchanger 300, electronic expansion valve 100, outdoor heat exchanger 200, and compressor 500. The indoor heat exchanger 300 functions as a condenser, and the outdoor heat exchanger 200 functions as an evaporator.

[0047] The expansion valve 100 depressurizes and expands the liquid refrigerant flowing into the outdoor heat exchanger 200 during cooling operation or into the liquid refrigerant flowing into the indoor heat exchanger 300 during heating operation, and then controls the flow rate of the refrigerant. Furthermore, in Figure 5 In this embodiment, an electronic expansion valve 100 is installed in the refrigeration cycle system such that liquid refrigerant flows from the outdoor heat exchanger 200 into the first connector pipe 13 during cooling operation, and liquid refrigerant from the indoor heat exchanger 300 flows into the second connector pipe 18 during heating operation. However, it is not limited to this; the electronic expansion valve 100 may also be installed in the refrigeration cycle system such that liquid refrigerant from the outdoor heat exchanger 200 flows into the second connector pipe 18 during cooling operation, and liquid refrigerant from the indoor heat exchanger 300 flows into the first connector pipe 13 during heating operation.

[0048] Next, the operation of valve device 1 will be explained. Valve device 1 is in a fully closed state (not shown) by the actuation of drive unit 70. Figure 3 The system switches between a small flow control state (shown) and a fully open state (not shown). In the fully closed state, the valve core 50 is seated (closest to) the valve seat 15, and the refrigerant (fluid) flow rate is 0. When the stepper motor 71 is driven from this state, the magnetic rotor 72 and drive shaft 74 rotate, and through the threaded feed mechanism of the external thread 75 and internal thread 45, the magnetic rotor 72 and drive shaft 74 move to one side L1 in the direction of axis L. With this movement, the valve core 50 rises, and the valve port 14 opens. Thus, the refrigerant flows between the first connector pipe 13, the first port 12, the valve chamber 11, the valve port 14, the second port 17, and the second connector pipe 18.

[0049] like Figure 3As shown, immediately after the valve is opened, the valve seat cone portion 15a of the valve seat 15 and the valve core cone portion 58 of the valve core 50 are positioned opposite each other in the intersecting direction X, creating a small gap S with a variable predetermined interval between them. When fluid flows through this small gap S, the flow rate is precisely controlled according to the size of the small gap S, thus the small gap S constitutes a small flow control region 80 for small flow control of the refrigerant. The state in which the refrigerant flows through this small flow control region 80 is defined as the small flow control state. The specific size of the small flow control region 80 can be appropriately selected by considering the amount of pulse applied to the stepper motor 71, the lifting amount of the valve core 50 corresponding to the pulse, etc. However, from the viewpoint of fully utilizing the noise reduction effect of the small cone portion 58b of the valve core 50 described later, for example, the size of the small flow control region 80 is preferably such that the maximum dimension S1 in the axial direction L is 35 μm or less, and the maximum dimension S2 in the intersecting direction X is 13 μm or less. In this embodiment, when approximately 5 to 6 pulses are applied to the stepper motor 71, the maximum size S1 is 35 μm and the maximum size S2 is 13 μm.

[0050] After the initial flow control state, as the valve core 50 is lifted more, the opposing portion of the valve seat cone 15a in the intersecting direction X changes to a second cone 56 and a foremost end 57. The gap between the valve seat 15 and the valve core 50 increases, thus increasing the flow rate of refrigerant flowing through the valve port 14. Then, when the needle component 52 is fully withdrawn from the valve port 14, it becomes 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 refrigerant flow rate.

[0051] In the valve device 1 that constitutes the refrigeration cycle system as described in this embodiment, the noise from the refrigerant during refrigerant flow can sometimes be a problem, and it is necessary to reduce this noise. In particular, in recent years, with the application of the valve device 1 in refrigeration and air conditioning equipment, precise refrigerant flow control has become necessary due to the increasing precision of temperature control; therefore, high quietness is required under such precise flow control conditions. Therefore, in this embodiment, the surface structure of the valve seat cone portion 15a and the valve core cone portion 58 was studied to reduce the refrigerant noise under precise flow control conditions. Figure 3 As shown, the valve core tapered portion 58 of the valve core 50 is formed by machining concentric or spiral-shaped minute irregularities arranged or continuous around the axis L. In this irregularity, the concave areas are designated as minute valleys 58a, and the convex areas as minute hills 58b.

[0052] like Figure 4 As shown, multiple small valleys 58a and small hills 58b are arranged adjacently in an inclined direction from the end of one side L1 (base end side) of the valve core cone portion 58 to the end of the other side L2 (front end side). Furthermore, although in Figure 4While not visually confirmable, machined unevenness is also formed in the valve seat cone portion 15a. Furthermore, the "maximum height RzB," one of the parameters of the surface characteristics (surface roughness, JISB 0601:2013) of the valve core cone portion 58, is greater than the "maximum height RzA (not shown)" of the valve seat cone portion 15a. That is, when the maximum height of the valve seat cone portion 15a (concave portion) is set to "maximum height RzA" and the maximum height of the valve core cone portion 58 (convex portion) is set to "maximum height RzB," RzA < RzB. Consequently, the refrigerant passing through the micro-flow control region 80 meanders along the small hill 58b and small valley 58a while moving along the valve seat cone portion 15a towards the other side L2.

[0053] By meandering the refrigerant, the refrigerant flow rate can be reduced, thus decreasing the noise level as the refrigerant passes through. From the viewpoint of appropriately reducing the refrigerant flow rate, the maximum height RzA is preferably adjusted to a range of 0.01 μm < RzA < 0.5 μm, and the maximum height RzB is preferably adjusted to a range of 0.8 μm < RzB < 6.3 μm. Furthermore, as... Figure 3 As shown, when the length of the inclined direction from one side L1 (upper end) of the valve seat cone portion 15a to the other side L2 (lower end) is defined as "length LA", and the interval in the inclined direction of adjacent small hills 58b in the valve core cone portion 58 is defined as "interval LtB", it is preferable that LtB < 1 / 2 LA. Furthermore, "length LA" and "interval LtB" are more preferably 5 μm < LtB < 60 μm and 10 μm < LA < 150 μm, and even more preferably 5 μm < LtB < 30 μm and 10 μm < LA < 75 μm. Thus, the refrigerant passing through the micro-flow control region 80 meanders multiple times (at least twice) along the small hills 58b and small valleys 58a. Therefore, this meandering allows the flow rate of the refrigerant passing through the micro-flow control region 80 to be appropriately attenuated, reducing the noise of the refrigerant passing through.

[0054] The valve core tapered portion 58 having the surface characteristics described above can be formed by machining, for example, forming concentric or spiral micro-valve portions 58a and micro-mountain portions 58b around the axis L on the outer peripheral surface of the needle member 52. Furthermore, the valve seat tapered portion 15a can be formed by precision machining, for example, on the upper end of the valve port 14.

[0055] Next, based on Figures 6-10This document describes a measured example of noise and flow rate under low-flow control conditions for valve device 1. In this example, the operating conditions of valve device 1 were set as follows: First, the pressure P1 in the first connector pipe 13 was set to 2.0–3.0 MPa (megapascals), and the pressure difference ΔP between the first connector pipe 13 and the second connector pipe 18 was set to 0.05 MPa or less. Furthermore, the inner diameter of the small-diameter portion 14a of the valve port 14 was set to any one of 2.2Φ, 3.4Φ, 4.2Φ, 8.0Φ, and 9.0Φ. Additionally, the refrigerant was set to flow from the first connector pipe 13 side to the second connector pipe 18 side.

[0056] Figure 6 For the valve device 1 with a 2.2Φ orifice diameter of the small diameter portion 14a, the relationship between the ratio of "interval LtB" to "length LA" (i.e., "LtB / LA") and the "noise reduction value (dB(A))" and "flow rate change (%)" is shown. Furthermore, the "noise reduction value" is the difference between the noise (dB(A)) of the valve device 1 of this embodiment, which is identical to the valve device 1 in this embodiment in terms of construction except for the different surface characteristics (such as the valve seat cone portion 15a and the valve core cone portion 58) under micro-flow control conditions, and the actual flow rate at the valve orifice 14, under micro-flow control conditions, is expressed proportionally as follows: with the design value of the flow rate at the valve orifice 14 set to 100% when the lifting amount of the valve core 50 and the opening degree of the valve orifice 14 are at a predetermined size.

[0057] like Figure 6 As shown, when LtB / LA = 1 / 30 (the leftmost point ●), the "noise reduction value" is approximately -1.1 dB(A) . In contrast, when LtB / LA = 1 / 15 (the third point from the left ●), the "noise reduction value" is approximately -2.9 dB(A) . That is, compared to the case where LtB / LA = 1 / 30, the case where LtB / LA = 1 / 15 further reduces noise. On the other hand, even when LtB / LA = 1 / 2 (the third point from the right ●), LtB / LA = 3 / 4 (the rightmost point ●), etc., making the value of LtB / LA greater than 1 / 15, the "noise reduction value" does not significantly exceed -2.9 dB(A) . On the other hand, as the value of LtB / LA is gradually increased until LtB / LA = 1 / 2 (the third point from the right ◇), the "flow rate change rate" becomes approximately 1%, and the flow rate at valve port 14 does not deviate significantly from the design value.

[0058] However, when LtB / LA is greater than 1 / 2 (e.g., LtB / LA = 2 / 3 (second point from the right) or LtB / LA = 3 / 4 (rightmost point)), the flow rate variation is approximately 3% to 5%, and the flow rate at valve port 14 shows a significant deviation from the design value. This tendency also applies when the diameter of the small diameter section 14a is different. Figure 7 The relationship between “LtB / LA” and “noise reduction value (dB(A))” and “flow rate change (%)” is shown for valve device 1 with a diameter of 3.4Φ in the small diameter section 14a. Figure 8 The relationship between “LtB / LA” and “noise reduction value (dB(A))” and “flow rate change (%)” is shown for valve device 1 with a diameter of 4.2Φ in the small diameter section 14a. Figure 9 The relationship between “LtB / LA” and “noise reduction value (dB(A))” and “flow rate change (%)” is shown for valve device 1 with a diameter of 8.0Φ in the small diameter section 14a. Figure 10 The relationship between “LtB / LA” and “noise reduction value (dB(A))” and “flow rate change (%)” is shown for valve device 1 with a diameter of 9.0Φ in the small diameter section 14a.

[0059] exist Figures 7-10 In any of the graphs, when 1 / 15 (the third point from the left, ●) < LtB / LA, the "noise reduction value" is approximately -2.8 dB(A)", showing a significant improvement, and even increasing LtB / LA does not result in a further significant change. Furthermore, regarding the "flow rate change," up to LtB / LA = 1 / 2 (the third point from the right, ◇), the "flow rate change" is approximately 1%, and the actual flow rate at valve port 14 does not deviate significantly from the design value. However, when LtB / LA is greater than 1 / 2 (e.g., LtB / LA = 2 / 3 (the second point from the right, ◇), LtB / LA = 3 / 4 (the rightmost point, ◇)), the flow rate change is approximately 3% to 5%, and the flow rate at valve port 14 shows a significant deviation from the design value. Based on the above results, from the viewpoint of appropriately reducing noise within the range where the flow rate does not deviate from the design value and does not have a significant impact on flow control, the "length LA" and "interval LtB" are more preferably set within the management range of 1 / 15 < LtB / LA < 1 / 2.

[0060] According to the above-described embodiment, during the period when the refrigerant (fluid) flows through the micro-flow control region 80, where the maximum height RzA of the valve seat cone portion 15a (concave portion) is controlled to be less than the maximum height RzB of the valve core cone portion 58 (convex portion), it meanders multiple times (at least twice) along the micro-mountains 58b and micro-valve portions 58a formed on the surface of the valve core cone portion 58. This meandering reduces the flow velocity of the fluid passing through the micro-flow control region 80, thereby reducing the noise of the refrigerant passing through. Therefore, a valve device 1 that reduces the noise of the refrigerant passing through the micro-flow control region 80 can be provided.

[0061] In addition, for "maximum height RzA" and "maximum height RzB", 0.01μm < RzA < 0.5μm and 0.8μm < RzB < 6.3μm are set. This can better balance the stable flow control in the micro-flow control region 80 and the refrigerant noise reduction caused by the appropriate attenuation of the refrigerant flow rate in the micro-flow control region 80.

[0062] In addition, the "interval LtB" and "length LA" are set to 5μm < LtB < 60μm and 10μm < LA < 150μm. This allows the refrigerant to meander multiple times along the tiny hills 58b and tiny valleys 58a formed on the surface of the valve core cone 58. This better balances stable flow control in the micro-flow control region 80 with the appropriate reduction in refrigerant velocity in the micro-flow control region 80, resulting in reduced refrigerant noise.

[0063] In addition, for "interval LtB" and "length LA", it is set to 5μm < LtB < 30μm and 10μm < LA < 75μm, which further facilitates the tortuosity of the refrigerant. This can better balance the stable flow control at the micro-flow control region 80 and the appropriate attenuation of the refrigerant flow rate in the micro-flow control region 80, resulting in a reduction in refrigerant noise.

[0064] Furthermore, in the micro-flow control region 80, the maximum dimension in the axial direction L is set to 35 μm or less, and the maximum dimension in the cross direction X is set to 13 μm or less. Thus, even in the extremely small micro-flow control region 80 immediately after the valve core 50 has just left the valve seat 15, the refrigerant can meander multiple times along the small hills 58b and small valleys 58a, better balancing stable flow control with appropriate reduction in refrigerant velocity and refrigerant noise. Moreover, the maximum dimension in the axial direction L of this micro-flow control region 80 can be adjusted, for example, by taking into account the number of pulses of the stepper motor 71 driving the valve core 50 and the lifting amount (movement amount) of the valve core 50, to achieve the value immediately after the valve core 50 has left the seat.

[0065] Furthermore, according to the above embodiment, a refrigeration cycle system can be constructed using a valve device 1, namely an electronic expansion valve 100 (electric valve, expansion valve), which reduces the noise of the refrigerant in the small flow control area 80.

[0066] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the specific structure is not limited to these embodiments, and design changes that do not depart from the spirit of the present invention are also included in the present invention. For example, in this embodiment, as an example of valve device 1, an electric valve in which the valve core 50 is driven by a stepper motor 71 is shown. However, valve device 1 is not limited to this, and may also be a manual valve with a manually driven valve core, a solenoid valve driven by a solenoid, etc. In addition, even in an electric valve, its driving unit is not limited to a stepper motor, and may be other motors.

[0067] In this embodiment, a convex portion is formed on the valve core 50 side, and a concave portion is formed on the valve seat 15 side. However, it is not limited to this structure. A columnar member extending along the axis L can be arranged at the center of the valve port 14, and a valve seat can be formed at the end on the valve chamber 11 side. A cylindrical valve core is prepared to surround the valve seat and can approach or move away from the valve seat. Moreover, a convex portion can be formed in the portion of the valve seat near the valve core, and a concave portion can be formed in the portion of the valve core near the valve seat. That is, one of the valve seat tapered portion 15a and the valve core tapered portion 58 can be formed into a mortar-shaped concave portion, and the other of the valve seat tapered portion 15a and the valve core tapered portion 58 can be formed into a frustum-shaped convex portion.

Claims

1. A valve device comprising: a valve port through which fluid passes; a metal valve seat having a valve seat cone portion formed by a conical surface; a metal valve core having a valve core cone portion formed by a conical surface adjacent to or away from the valve seat cone portion; a drive unit for driving the valve core; and a micro-flow control region consisting of a micro-gap, a variable predetermined interval gap generated between the valve seat cone portion and the valve core cone portion, for performing micro-flow control of the fluid. The valve device is characterized in that... One of the valve seat tapered portion and the valve core tapered portion constitutes a mortar-shaped concave portion. The other of the conical portion of the valve seat and the conical portion of the valve core constitutes a convex portion in the shape of a frustum of a cone. At least a plurality of small ridges are formed on the surface of the convex portion in an inclined direction from the base end side of the valve core tapered portion toward the front end side. When the maximum height of the surface roughness of the concave portion is set to RzA and the maximum height of the convex portion is set to RzB, RzA < RzB, and, When the interval between the inclined directions of adjacent micro-hills is set as LtB, and the length of the inclined direction from the upper end to the lower end of the valve seat cone is set as LA, LtB < 1 / 2LA.

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

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

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

5. The valve device according to claim 1, characterized in that, In the micro-flow control region, the maximum dimension in the axial direction is less than 35 μm.

6. The valve device according to claim 1, characterized in that, In the micro-flow control region, the maximum dimension of the intersection direction with the axial direction is less than 13 μm.

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

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