Motor-operated valve

Abstract

To suppress generation of noise and vibration of a motor valve by stabilizing the state of a coolant in an auxiliary valve chamber and reducing the acoustic pressure of the coolant passing sound at a port throttle portion between an auxiliary valve port formed on a main valve body and an auxiliary valve body, for a motor valve which controls the flow rate in a small flow-rate control range of the coolant with the port throttle portion.SOLUTION: A guide boss portion 41 inserted into an auxiliary valve chamber 3R is provided for an auxiliary valve body 4. A throttle passage S1 is formed by a clearance between an inner circumference of the auxiliary valve chamber 3R and an outer circumference of the guide boss portion 41. A coolant flowing into a main valve chamber 1R flows to the auxiliary valve chamber 3R through the throttle passage S1 from a communication passage 3b. The coolant in the main valve chamber 1R is stabilized by passing through the throttle passage S1 even when the coolant is a mixture of a gas phase coolant and a liquid phase coolant. The coolant passes through a port throttle portion P from the auxiliary valve chamber 3R.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a motor-operated valve for use in a refrigeration cycle system or the like. [Background technology]

[0002] Conventionally, as an electric valve provided in the refrigeration cycle of an air conditioner, there is an electric valve that controls a flow rate in a small flow rate control region and a large flow rate region. Such an electric valve is disclosed, for example, in JP 2020-106086 A (Patent Document 1).

[0003] Fig. 9 is an enlarged cross-sectional view of the main part of this conventional motor-operated valve. This conventional motor-operated valve has a main valve element a and a sub-valve element b, and controls the small flow rate by allowing the refrigerant to flow from the communication passage b3 of the sub-valve element b to the sub-valve chamber a1 of the main valve element a and throttling the refrigerant at the port throttling section P, which is the gap between the needle valve b2 of the sub-valve element b and the sub-valve port a2. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-106086 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the motor-operated valve of Patent Document 1, when the state of the refrigerant flowing into the communication passage b3 is unstable, such as when liquid phase is mixed with gas phase, the refrigerant flows into the throttle port section P without being stabilized. This causes a problem of increased refrigerant passing noise through the throttle port section P.

[0006] The present invention has an objective of stabilizing the state of refrigerant in a sub-valve chamber and reducing the sound pressure of the refrigerant passing through the port restriction section in an electric valve in which the main valve port is fully closed by the main valve body and the flow rate of refrigerant in a small flow rate control range is controlled by a port restriction section formed on the main valve body. This objective is to suppress the generation of noise and vibration in the electric valve by stabilizing the state of refrigerant in a sub-valve chamber and reducing the sound pressure of the refrigerant passing through the port restriction section. [Means for solving the problem]

[0007] The motor-operated valve of the present invention comprises a valve body having a main valve chamber and a main valve port, a main valve element which opens and closes the main valve port, and a sub-valve element which changes the opening of a sub-valve port formed in the main valve element, the main valve element being connected to the sub-valve element so as to be movable in the axial direction relative to the sub-valve element, the main valve element having a communication passage one opening of which opens into the main valve chamber, a sub-valve chamber being formed by a flow path from the other opening of the communication passage to the sub-valve port, the main valve element closing the main valve port, and a small valve element which throttles the fluid flowing from the main valve chamber through the communication passage into the sub-valve port by a port throttle section in a gap between a needle valve of the sub-valve element and the sub-valve port. a motor-operated valve having a flow rate control region, the motor-operated valve including a stabilizing structure for stabilizing a state of fluid in the sub-valve chamber between the communication passage and the sub-valve port, the stabilizing structure including an expanded space opening to the communication passage side of the sub-valve chamber, and a throttle passage communicating the expanded space with the sub-valve port and having a cross-sectional area viewed from the axial direction smaller than the cross-sectional area of ​​the expanded space viewed from the axial direction, the throttle passage communicating with the main valve chamber and the port throttle portion regardless of the opening degree of the sub-valve port, and a disk-shaped portion extending in a direction intersecting with the axial direction is provided between the needle valve and the expanded space of the sub-valve body, In the axial direction, regardless of the opening degree of the sub-valve port, the disk-shaped portion is located on the side of the communication passage where the port throttle portion is located, The disk-shaped portion is provided with a through hole penetrating in the axial direction at a position radially outward from the needle valve, and the needle valve has a cylindrical portion that faces the inner wall of the auxiliary valve port when inserted into the auxiliary valve port.

[0009] Also, The throttle passage is formed by a clearance between the inner periphery of the sub-valve chamber and the outer periphery of the sub-valve body inserted into the sub-valve chamber. It is characterized by:

[0010] Also, The throttle passage is The inner periphery of the auxiliary valve chamber and the Disk-shaped part The clearance between the outer circumference of the Ruko The motor-operated valve is preferably characterized by the above.

[0012] The relationship between the opening area [A] of the communication passage, the opening area [B] of the throttle passage, and the opening area [C] of the port throttle portion is as follows: A>B>C It is preferable that the motor-operated valve is characterized in that:

[0013] The relationship between the opening area [A] of the communication passage, the opening area [B] of the throttle passage, the opening area [C] of the port throttle portion, and the opening area [D] of the through hole is as follows: A>B+D>C It is preferable that the motor-operated valve is characterized in that:

[0014] Also, before In a preferred embodiment of the motor-operated valve, the height from the port throttle portion to the communication passage is greater than the radius of the auxiliary valve chamber. Effect of the Invention

[0015] According to the motor-operated valve of the present invention, even if the refrigerant is in a state where liquid phase refrigerant is mixed with gas phase refrigerant, the state of the refrigerant in the sub-valve chamber is stabilized, and the state of the refrigerant before passing from the sub-valve chamber to the port throttle portion (sub-valve port) is stabilized. Therefore, the sound pressure of the refrigerant passing through the port throttle portion, which is the gap between the needle valve and the sub-valve port, is reduced, and the generation of noise and vibration of the motor-operated valve can be suppressed. [Brief description of the drawings]

[0016] [Figure 1] FIG. 2 is a vertical sectional view of the motor-operated valve according to the first embodiment of the present invention in a small flow rate control range state. [Diagram 2] FIG. 2 is an enlarged cross-sectional view of a main portion of the motor-operated valve of the first embodiment in a small flow rate control range state. [Diagram 3] FIG. 2 is an enlarged cross-sectional view of a main portion of the motor-operated valve of the first embodiment in a large flow rate range state. [Figure 4] FIG. 11 is an enlarged cross-sectional view of a main portion of a motor-operated valve according to a second embodiment of the present invention in a small flow rate control range state. [Diagram 5] FIG. 11 is an enlarged cross-sectional view of a main portion of the motor-operated valve of the second embodiment in a large flow rate range state. [Figure 6]FIG. 11 is an enlarged cross-sectional view of a main portion of a motor-operated valve according to a third embodiment of the present invention in a small flow rate control range state. [Figure 7] FIG. 11 is an enlarged cross-sectional view of a main portion of a motor-operated valve according to a fourth embodiment of the present invention in a small flow rate control range state. [Figure 8] FIG. 13 is an enlarged cross-sectional view of a main portion of a motor-operated valve according to a fifth embodiment of the present invention in a small flow rate control range state. [Figure 9] FIG. 11 is an enlarged cross-sectional view of a main portion of a conventional motor-operated valve. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Next, an embodiment of the motor-operated valve of the present invention will be described with reference to the drawings. Fig. 1 is a vertical cross-sectional view of the motor-operated valve of the first embodiment in a small flow rate control range state, Fig. 2 is an enlarged cross-sectional view of the main parts of the motor-operated valve in a small flow rate control range state (sub-valve lower end position), and Fig. 3 is an enlarged cross-sectional view of the main parts of the motor-operated valve in a large flow rate range state (sub-valve upper end position). The concept of "upper and lower" in the following description corresponds to the upper and lower in the drawing of Fig. 1. This motor-operated valve 100 comprises a valve housing 1, a guide member 2, a main valve element 3, a sub-valve element 4, and a drive unit 5.

[0018] The valve housing 1 is formed in a substantially cylindrical shape from brass, stainless steel, or the like, and has a main valve chamber 1R inside. A first joint pipe 11 that is connected to the main valve chamber 1R is connected to one side of the outer periphery of the valve housing 1, and a second joint pipe 12 is connected to a cylindrical portion extending downward from the lower end. A main valve seat 13 is formed on the main valve chamber 1R side of the second joint pipe 12 of the valve housing 1, and the inside of this main valve seat 13 is a main valve port 13a. The main valve port 13a is a cylindrical hole centered on the axis L, and the second joint pipe 12 is connected to the main valve chamber 1R through the main valve port 13a. In this embodiment, the main valve seat 13 is formed integrally with the valve housing 1, but a valve seat member having a main valve port may be provided separately from the valve housing, and the valve seat member may be assembled to the valve housing.

[0019] A guide member 2 is attached to the opening at the upper end of the valve housing 1. The guide member 2 has a fitting portion 21 that fits into the inner peripheral surface of the valve housing 1, a substantially cylindrical guide portion 22 located above the fitting portion 21, a holder portion 23 that extends from the upper portion of the guide portion 22, and a ring-shaped fixing metal fitting 24 made of a metal plate that is provided on the fitting portion 21 and protrudes to the outer periphery of the fitting portion 21. The fitting portion 21, the upper guide portion 22, and the holder portion 23 are configured as an integrated resin product, and the fixing metal fitting 24 is provided integrally with the resin fitting portion 21 by insert molding. The fitting portion 21 of the guide member 2 may be press-fitted into the valve housing 1.

[0020] The guide member 2 is assembled to the valve housing 1 by a fitting portion 21, and is fixed by welding to the upper end of the valve housing 1 via a fixing bracket 24. In the guide member 2, a cylindrical guide hole 2A coaxial with the axis L is formed inside the fitting portion 21 and the guide portion 22, and a female threaded portion 23a coaxial with the guide hole 2A and a threaded hole for the female threaded portion 23a are formed in the center of the holder portion 23. The main valve element 3 is disposed in the guide hole 2A.

[0021] The main valve element 3 is composed of a main valve portion 31 that seats and leaves the main valve seat 13, and a retaining portion 32 that is a side wall of the main valve element 3 and retains the sub-valve element 4. A cylindrical opening 3A is formed inside the main valve portion 31, and a cylindrical sub-valve chamber 3R is formed inside the retaining portion 32, with the inner circumferential surface of the sub-valve chamber 3R serving as a sub-valve guide hole 3B. A cylindrical sub-valve port 3a is formed between the main valve portion 31 and the retaining portion 32, opening from the sub-valve chamber 3R to the opening 3A side with the axis L as the center.

[0022] A communication passage 3b is formed on the side surface of the holding portion 32 of the main valve body 3, which communicates from the main valve chamber 1R to the sub-valve chamber 3R in a direction intersecting the axis L. In this embodiment, a plurality of communication passages 3b (for example, four communication passages) are formed radially at rotationally symmetric positions around the axis L. The main valve body 3 has a retainer 34 at the upper end of the holding portion 32, and a main valve spring 35 between the retainer 34 and the upper end of the guide hole 2A of the guide member 2, and the main valve body 3 is biased toward the main valve seat 13 (closing direction) by the main valve spring 35. A sound absorbing member 36 is disposed inside the opening 3A of the main valve portion 31. The communication passages 3b are not limited to a form in which a plurality of communication passages 3b are formed radially at rotationally symmetric positions, and the number of communication passages 3b may be one, or multiple communication passages may be formed at unequal intervals.

[0023] The sub-valve element 4 is provided at the lower end of the rotor shaft 51. The sub-valve element 4 is formed integrally with the rotor shaft. The sub-valve element 4 is composed of a guide boss portion 41 and a needle valve 42. The tip of the needle valve 42 of the sub-valve element 4 is inserted into the sub-valve port 3a in the axial direction L, and a small flow rate of refrigerant flows through a port throttle portion P, which is a gap between the needle valve 42 and the sub-valve port 3a, to perform small flow rate control. An annular washer 43 made of a lubricating resin is disposed at the upper end of the guide boss portion 41, and the guide boss portion 41 is inserted into the sub-valve guide hole 3B. The clearance between the outer peripheral surface of the guide boss portion 41 and the inner peripheral surface of the sub-valve guide hole 3B constitutes a throttle passage S1 as a "stabilizing structure". The sub-valve element 4 and the rotor shaft 51 may be formed separately and then assembled.

[0024] A case 14 is airtightly fixed to the upper end of the valve housing 1 by welding or the like, and a drive unit 5 is configured inside and outside this case 14. The drive unit 5 includes a stepping motor 5A, a screw feed mechanism 5B that moves the sub-valve element 4 forward and backward by the rotation of the stepping motor 5A, and a stopper mechanism 5C that regulates the rotation of the stepping motor 5A.

[0025] The stepping motor 5A is composed of a rotor shaft 51, a magnet rotor 52 rotatably arranged inside the case 14, a stator coil 53 arranged facing the magnet rotor 52 on the outer periphery of the case 14, and other components such as a yoke and an exterior member (not shown). The rotor shaft 51 is attached to the center of the magnet rotor 52 via a bush, and a male screw portion 51a is formed on the outer periphery of the rotor shaft 51 on the guide member 2 side. The male screw portion 51a is screwed into the female screw portion 23a of the guide member 2, so that the guide member 2 supports the rotor shaft 51 on the axis L. The female screw portion 23a of the guide member 2 and the male screw portion 51a of the rotor shaft 51 constitute a screw feed mechanism 5B. A cylindrical portion 14a that holds a rotation stopper mechanism 5C is provided on the inner ceiling of the case 14, and a guide member 54 that guides the upper end of the rotor shaft 51 is arranged inside the cylindrical portion 14a.

[0026] With the above configuration, when the stepping motor 5A is driven, the magnet rotor 52 and the rotor shaft 51 rotate, and the rotor shaft 51 moves together with the magnet rotor 52 in the axial direction L by the screw feed mechanism 5B of the male screw portion 51a and the female screw portion 23a. Then, the sub-valve element 4 moves forward and backward in the axial direction L, and the needle valve 42 of the sub-valve element 4 approaches or moves away from the sub-valve port 3a. When the sub-valve element 4 rises, the washer 43 engages with the retainer 34 of the main valve element 3 (sub-valve upper end position), and the main valve element 3 moves together with the sub-valve element 4, and the main valve portion 31 of the main valve element 3 leaves the main valve seat 13. As a result, the main valve port 13a is fully opened and in the large flow rate range state (note that immediately after the main valve element 3 leaves the main valve seat 13, the main valve port 13a is fully opened and in the large flow rate range state, which is the same as in FIG. 3 described later). In addition, a protrusion 52a is formed on the magnet rotor 52, and as the magnet rotor 52 rotates, the protrusion 52a activates a rotation stopper mechanism 5C, thereby regulating the lowermost and uppermost positions of the rotor shaft 51 (and the magnet rotor 52).

[0027] In the small flow control region state of FIG. 1, the main valve element 3 is seated on the main valve seat 13 and the main valve port 13a is closed, and the needle valve 42 of the sub-valve element 4 controls the opening degree of the sub-valve port 3a (the opening area of ​​the port throttle section P) to control the small flow rate. At this time, the refrigerant that flows into the main valve chamber 1R from the first joint pipe 11 flows from the communication passage 3b through the throttle passage S1 to the sub-valve chamber 3R. In this way, since the refrigerant flows into the sub-valve chamber 3R through the throttle passage S1, even if the refrigerant in the main valve chamber 1R is a mixture of gas phase refrigerant and liquid phase refrigerant, this refrigerant is stabilized by passing through the throttle passage S1, and the state of the refrigerant before passing from the sub-valve chamber 3R through the port throttle section P is stabilized. Therefore, the sound pressure of the refrigerant passing through the port throttle section P is reduced, and the generation of noise and vibration of the motor-operated valve 100 can be suppressed.

[0028] In the conventional motor-operated valve shown in FIG. 9, the height [H1] from the upper edge position of the sub-valve port a2 to the bottom of the communication passage b3 is small, so the distance that the refrigerant flows from the communication passage b3 to the port throttle section P is short. In contrast, in this embodiment, as shown in FIG. 2, the height [H3] from the upper edge position of the sub-valve port 3a to the bottom of the communication passage 3b is sufficiently higher than the height [H1] in the conventional motor-operated valve, that is, this height [H3] is larger than the radius of the inner diameter of the sub-valve chamber 3a (the inner diameter of the guide hole 3B). In this way, the height [H3] from the upper edge position of the sub-valve port 3a to the bottom of the communication passage 3b is sufficiently long, so that the effect of stabilizing the refrigerant is increased. Note that FIG. 2 shows the lower end position of the sub-valve body 4 in the small flow rate control region state of the motor-operated valve 100, and in this state, the height [H2] from the sub-valve port 3a to the lower end of the throttle passage S1 is lower than the height [H3] from the upper edge position of the sub-valve port 3a to the bottom of the communication passage 3b. 3, the height [H4] from the upper edge of the sub-valve port 3a to the lower end of the throttle passage S1 when the sub-valve element 4 is in the upper end position is also lower than the height [H3] from the upper edge of the sub-valve port 3a to the bottom of the communication passage 3b. This ensures that the throttle passage S1 is always open.

[0029] The relationship between the opening area [A] of the communication passage 3b, the opening area [B] of the throttle passage S1, and the opening area [C] of the port throttle portion P is as follows: A>B>C This enhances the effect of stabilizing the refrigerant state. In a configuration in which a plurality of communication passages 3b are provided, the opening area is the sum of the opening areas of the plurality of communication passages 3b. In this embodiment, the opening area of ​​the port throttle section P is set to have the above relationship at the opening area C at the inner diameter of the sub-valve port 3a when the needle valve 42 is not inserted into the sub-valve port 3a, but may be set to have the above relationship at the opening area C of the gap between the sub-valve port 3a and the needle valve 42 when the needle valve 42 is inserted into the sub-valve port 3a.

[0030] Fig. 4 is an enlarged cross-sectional view of a main part of a motor-operated valve according to a second embodiment of the present invention in a small flow rate control range state, and Fig. 5 is an enlarged cross-sectional view of a main part of the motor-operated valve according to the second embodiment in a large flow rate range state. In the second to fifth embodiments described below, other parts than the main parts shown in the drawings are the same as those in Fig. 1 of the first embodiment. In the following embodiments, the same members and elements as those in the first embodiment are denoted by the same reference numerals, and detailed explanations will be omitted. The second embodiment differs from the first embodiment in the configuration of the sub-valve body 4'.

[0031] The sub-valve element 4' in the second embodiment includes a guide boss 41' similar to that in the first embodiment, which is inserted into the sub-valve chamber 3R, and a flange 43' formed at a position spaced from the guide boss 41' toward the sub-valve port 3a. The sub-valve element 4' further includes an expanded space 4a' between the guide boss 41' and the flange 43'. The flange 43' is disk-shaped, and a throttle passage S2 is formed by a clearance between the outer circumferential surface of the flange 43' and the inner circumferential surface of the sub-valve guide hole 3B. The expanded space 4a' opens into the communication passage 3b. The throttle passage S2 and the expanded space 4a' form a "stabilizing structure." The refrigerant that flows into the main valve chamber 1R from the first joint pipe 11 flows out of the communication passage 3b into the expanded space 4a', and then flows into the sub-valve chamber 3R through the throttle passage S2. In this way, the refrigerant flows into the sub-valve chamber 3R through the expanded space 4a' and the throttle passage S2. Therefore, even if the ratio of the liquid phase increases due to a change in the ratio of the gas phase and the liquid phase in the refrigerant in the main valve chamber 1R, the gas phase and the liquid phase in the refrigerant are homogenized in the expanded space 4a', so the state of the refrigerant before passing from the sub-valve chamber 3R through the port throttle section S (sub-valve port) becomes more stable. Therefore, the sound pressure of the refrigerant passing through the port throttle section P is reduced, and the generation of noise and vibration of the motor-operated valve 100 can be suppressed. In addition, since the flow speed of the fluid flowing out to the expanded space 4a' is decelerated, the generation of noise and vibration due to the disappearance of bubbles generated when colliding with the wall surface can also be suppressed. In addition, in the large flow rate range state shown in FIG. 5, the height from the upper edge position of the sub-valve port 3a to the lower end of the throttle passage S2 at the upper end position of the sub-valve body 4' is also lower than the height from the upper edge position of the sub-valve port 3a to the bottom of the communication passage 3b. As a result, the throttle passage S2 can be always secured.

[0032] The relationship between the opening area [A] of the communication passage 3b, the opening area [B] of the throttle passage S2, and the opening area [C] of the port throttle portion P is as follows: A>B>C This enhances the effect of stabilizing the state of the refrigerant. The opening area A and the opening area C can be set in the same manner as in the first embodiment.

[0033] FIG. 6 is an enlarged cross-sectional view of a main part of the motor-operated valve according to the third embodiment in a small flow rate control region state. In this embodiment, an expanded space 3c is formed on the auxiliary valve chamber 3R side of the communication passage 3b. This third embodiment is similar to the second embodiment, and the refrigerant flows from the communication passage 3b to the expanded space 3c and further flows through the throttle passage S1 to the auxiliary valve chamber 3R. Therefore, even if the ratio of the liquid phase increases due to a change in the ratio of the gas phase and the liquid phase in the refrigerant in the main valve chamber 1R, the gas phase and the liquid phase in the refrigerant are homogenized in the expanded space 3c, so the state of the refrigerant before passing from the auxiliary valve chamber 3R to the port throttle section P (auxiliary valve port) becomes more stable. Therefore, the sound pressure of the refrigerant passing sound in the port throttle section P is reduced, and the generation of noise and vibration of the motor-operated valve 100 can be suppressed. In addition, the flow speed of the fluid flowing out to the expanded space 3c is decelerated, so that the generation of noise and vibration caused by the disappearance of bubbles generated when colliding with the wall surface can also be suppressed.

[0034] FIG. 7 is an enlarged cross-sectional view of a main part of the motor-operated valve of the fourth embodiment in a small flow control region state. In this fourth embodiment, an expanded space 44" is provided in a portion of the guide boss portion 41" of the sub-valve body 4" facing the communication passage 3b. This expanded space 44" is formed by a hole drilled from the outer circumferential surface of the guide boss portion 41" toward the axis L. The inner diameter of this hole is set to be sufficiently larger than the inner diameter of the communication passage 3b. In other words, this expanded space 44" is not provided over the entire circumference. In this fourth embodiment, as in the second embodiment, the refrigerant flows from the communication passage 3b into the expanded space 44" and further flows through the throttle passage S1 to the sub-valve chamber 3R. Therefore, even if the ratio of the liquid phase increases due to a change in the ratio of the gas phase and the liquid phase in the refrigerant in the main valve chamber 1R, the gas phase and the liquid phase in the refrigerant are homogenized in the expanded space 44", so the state of the refrigerant before passing from the sub-valve chamber 3R through the port throttle portion P (sub-valve port) is more stabilized. Therefore, the sound pressure of the refrigerant passing sound at the port throttle section P is reduced, and the generation of noise and vibration of the motor-operated valve 100 can be suppressed. In addition, since the flow velocity of the fluid flowing out to the expanded space 44'' is decelerated, the generation of noise and vibration caused by the disappearance of air bubbles generated when the fluid collides with the wall surface can also be suppressed.

[0035] FIG. 8 is an enlarged cross-sectional view of a main part of the motor-operated valve of the fifth embodiment in the small flow control region state. In this fifth embodiment, a through hole 45' is formed in the flange portion 43' of the sub-valve body 4' similar to that of the second embodiment, penetrating in the axial direction L from the expanded space 4a to the port throttle portion P side. In this fifth embodiment, the refrigerant flows out from the communication passage 3b to the expanded space 4a. Then, the refrigerant flows through the throttle passage S2 and the through hole 45' to the sub-valve chamber 3R. Therefore, even if the ratio of the liquid phase increases due to a change in the ratio of the gas phase and the liquid phase in the refrigerant in the main valve chamber 1R, the gas phase and the liquid phase in the refrigerant are homogenized in the expanded space 4a, so that the state of the refrigerant before passing from the sub-valve chamber 3R through the port throttle portion P is more stabilized. Therefore, the sound pressure of the refrigerant passing sound at the port throttle portion P is reduced, and the generation of noise and vibration of the motor-operated valve 100 can be suppressed. In addition, since the flow velocity of the fluid flowing out into the expanded space 4a is decelerated, it is also possible to suppress the generation of noise and vibration caused by the disappearance of air bubbles that are generated when the fluid collides with the wall surface.

[0036] The relationship between the opening area [A] of the communication passage 3b, the opening area [B] of the throttle passage S2, the opening area [C] of the port throttle portion, and the opening area [D] of the through hole 45′ is as follows: A>B+D>C This enhances the effect of stabilizing the state of the refrigerant. The opening area A and the opening area C can be set in the same manner as in the first embodiment.

[0037] In the third, fourth, and fifth embodiments, illustrations of the respective high flow rate range states are omitted, but similar to the first and second embodiments, a throttle passage can be always secured even in the high flow rate range state.

[0038] In addition, in the embodiment of the present invention, a communicating passage is provided in the main valve body, but instead of providing a communicating passage in the main valve body, it is also possible to provide a D-cut in the guide boss portion, for example, and form a communicating passage between the inner surface of the main valve body (auxiliary valve guide hole 3B) and the D-cut.

[0039] The above describes in detail an embodiment of the present invention with reference to the drawings, and also describes in detail other embodiments. However, the specific configuration is not limited to these embodiments, and the present invention also includes design changes and the like that do not deviate from the gist of the present invention. [Explanation of symbols]

[0040] 1 Valve housing 1R main valve chamber 11 First joint pipe 12 Second joint pipe 13 Main valve seat 13a Main valve port L axis 2 Guide member 2A Guide hole 22 Guide section 23 Holder part 23a Female thread 3 Main valve body 31 Main valve section 32 Holding part 3a Sub-valve port 3b Communication path 3B Auxiliary valve guide hole 3R Sub-valve chamber 4 Sub-valve body 41 Guide boss 42 Needle valve 5 Drive unit 5A stepper motor 5B Screw feed mechanism 5C Stopper mechanism 51 Rotor shaft 51a Male thread 52 Magnet rotor 53 Stator coil 4′ Sub-valve body 41' Guide boss 43′ Flange section 4a′ Expanded Space 4" Sub-valve body 41" Guide boss 44″ Expanded Space 3c Expanded Space 100 Motor-operated valve

Claims

1. a valve body having a main valve chamber and a main valve port, a main valve element for opening and closing the main valve port, and a sub-valve element for changing an opening degree of a sub-valve port formed in the main valve element, the main valve element is connected to the sub-valve element so as to be movable relative to the sub-valve element in an axial direction, and includes a communication passage having one opening that opens into the main valve chamber, a sub-valve chamber is formed by a flow path from the other opening of the communication passage to the sub-valve port, a valve having a small flow rate control region in which the main valve body closes the main valve port and fluid flowing from the main valve chamber through the communication passage to the sub-valve port is throttled by a port throttle portion in a gap between a needle valve of the sub-valve body and the sub-valve port, a stabilizing structure for stabilizing a state of fluid in the sub-valve chamber is provided between the communication passage and the sub-valve port, the stabilizing structure is constituted by an expanded space that opens to the communication passage side of the sub-valve chamber, and a throttle passage that communicates the expanded space with the sub-valve port and has a cross-sectional area, as viewed from the axial direction, smaller than a cross-sectional area of ​​the expanded space as viewed from the axial direction, Regardless of the opening degree of the sub-valve port, the throttle passage communicates between the main valve chamber and the port throttle portion, a disk-shaped portion extending in a direction intersecting with the axial direction is provided between the needle valve and the expanded space of the sub-valve body, In the axial direction, regardless of the opening degree of the sub-valve port, the disk-shaped portion is located on the side of the communication passage where the port throttle portion is located, The disk-shaped portion is provided with a through hole penetrating in the axial direction at a position radially outward from the needle valve, The needle valve has a cylindrical portion that faces an inner wall of the sub-valve port when inserted into the sub-valve port.

2. 2. The motor-operated valve according to claim 1, wherein the throttle passage is formed by a clearance between an inner periphery of the sub-valve chamber and an outer periphery of the sub-valve element inserted into the sub-valve chamber.

3. 2. The motor-operated valve according to claim 1, wherein the throttle passage is formed by a clearance between an inner periphery of the auxiliary valve chamber and an outer periphery of the disk-shaped portion.

4. The relationship between the opening area [A] of the communication passage, the opening area [B] of the throttle passage, and the opening area [C] of the port throttle portion is as follows: A>B>C 2. The motor-operated valve according to claim 1, characterized in that:

5. The relationship between the opening area [A] of the communication passage, the opening area [B] of the throttle passage, the opening area [C] of the port throttle portion, and the opening area [D] of the through hole is as follows: A>B+D>C 2. The motor-operated valve according to claim 1, characterized in that:

6. 6. The motor-operated valve according to claim 1, wherein a height from the port throttle portion to the communication passage is greater than a radius of the sub-valve chamber.

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