Motor-operated valve

Abstract

To provide a motor-operated valve capable of suppressing fluid leakage or the like while being relatively easily assembled.SOLUTION: The motor-operated vale 1 includes a vale main body 10 having a valve-seat 11e, a vale shaft 21 rotationally driven by a motor, a guide stem 15 attached to the vale main body 10, a vale holder held by the vale shaft 21, a vale element fixed to the vale holder and capable of coming into contact with and separating from the valve-seat 11e, and a seal holder 29 having a cylindrical fitted portion to which a fitting portion is fitted and a cylindrical holder base portion, the holder base portion being disposed in the vale main body. A gap between an outer periphery of the holder base portion and an inner periphery of the valve main body 10 is sealed, an annular seal body OR is disposed between the outer periphery of the holder base portion and the inner periphery of the valve holder, and a gap A in a radial direction between the fitting portion and the fitted portion is smaller than a gap B between the outer periphery of the holder base portion and the inner periphery of the valve main body 10.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a motor-operated valve. [Background technology]

[0002] A motor-driven electric valve has a screw mechanism in which the male thread of a valve stem, driven by a stepping motor, is threaded into a female threaded hole in the valve body. This screw mechanism rotates the valve stem around its axis and displaces it axially, increasing or decreasing the gap between the valve disc and the valve seat, thereby controlling the flow rate.

[0003] For example, Patent Document 1 discloses an electrically operated valve having a valve seat with a relatively large inner diameter to ensure a sufficient flow rate when the valve is open. In this electrically operated valve, a valve body is slidably fitted inside a cylindrical holding member, and a seal member disposed on the valve body seals the gap between the cylindrical holding member and the valve body. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-130271 Summary of the Invention [Problem to be solved by the invention]

[0005] The valve seat and valve disc disposed in the valve body have corresponding tapered surfaces, and when the valve disc is seated, the tapered surfaces come into close contact with each other to close the valve. Therefore, if the cylindrical retaining member and the valve seat are not coaxially aligned, eccentricity may occur between the valve disc and the cylindrical retaining member when the valve disc is seated on the valve seat, which could result in fluid leakage from the sealing member. For this reason, it is important to ensure the coaxiality between the cylindrical retaining member and the valve seat during assembly, but this makes assembly time-consuming.

[0006] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an electrically operated valve that can be assembled relatively easily and yet can suppress fluid leakage and the like. [Means for solving the problem]

[0007] The motor-operated valve of the present invention comprises: a valve body having a valve seat; a valve shaft that moves in the direction of the rotation axis as the motor rotates; a guide stem attached to the valve body and having a threaded portion that screws into a thread formed on the valve stem side; a valve holder held by the valve stem; a valve body fixed to the valve seat side of the valve holder; a seal holder that seals between an outer periphery of the valve holder and an inner periphery of the valve body, the valve body has a through hole that penetrates in the rotation axis direction and can be opened and closed, The present invention is characterized in that an annular seal body is disposed between the inner periphery of the seal holder and the outer periphery of the valve holder. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a motor-operated valve that can be assembled relatively easily and yet can suppress fluid leakage and the like. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a vertical cross-sectional view showing a motor-operated valve according to an embodiment of the present invention, in a closed state. [Figure 2] FIG. 2 is a longitudinal cross-sectional view showing the motor-operated valve according to the embodiment of the present invention, in a partially open state. [Figure 3] FIG. 3 is a vertical cross-sectional view showing the motor-operated valve according to the embodiment of the present invention, in a fully open state. [Figure 4] FIG. 4 is an enlarged view of the vicinity of the valve chamber of the motor-operated valve shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0011] Figures 1 to 3 are vertical cross-sectional views showing a motor-operated valve 1 according to an embodiment of the present invention. Figure 4 is an enlarged view showing the vicinity of the valve chamber of the motor-operated valve 1 shown in Figure 3. Here, "upper" refers to the rotor side relative to the valve seat, and "lower" refers to the valve seat side relative to the rotor.

[0012] (Configuration of motor-operated valve) The motor-operated valve 1 comprises a cylindrical valve body 10 with a bottom and an open top, a cylindrical can 45 with a top whose lower end is hermetically joined by welding or the like to the upper end surface of the valve body 10, a guide stem 15 fixed to the inside of the valve body 10, a valve shaft 21 disposed inside the guide stem 15, a rotor 30 connected and fixed to the valve shaft 21 so as to be rotatable integrally with it, and a stator 50 fitted onto the outer periphery of the can 45. The axis of the motor-operated valve 1 is designated as L.

[0013] The valve body 10 comprises a hollow cylindrical portion 10a and a bottom wall portion 10b, which are connected together. The thicknesses of the hollow cylindrical portion 10a and the bottom wall portion 10b are substantially equal. The interior of the hollow cylindrical portion 10a defines a valve chamber VC.

[0014] A circular opening 10d is formed in the center of the bottom wall portion 10b, and a valve seat member 11 is fixed to the opening 10d by brazing or the like. Here, the valve seat member 11 constitutes a part of the valve body 10.

[0015] The valve seat member 11 is composed of a hollow reduced-diameter cylindrical portion 11a and a hollow expanded-diameter cylindrical portion 11b connected together in the direction of the axis L. The reduced-diameter cylindrical portion 11a is fitted into the opening 10d and brazed. The end of the first pipe T1 is fitted into the inner periphery of the expanded-diameter cylindrical portion 11b and connected thereto by brazing or the like.

[0016] 4, the valve seat member 11 has a cylindrical upper opening 11c extending from the upper end, a tapered middle opening 11f whose diameter decreases downward, and a cylindrical orifice passage 11d whose diameter is smaller than that of the upper opening 11c. The first pipe T1 is positioned so as to abut against a step directly below the orifice passage 11d, and its inner diameter is larger than that of the orifice passage 11d. A tapered valve seat 11e whose diameter increases upward is formed on the inner periphery of the upper end of the upper opening 11c.

[0017] 1 to 3, an inlet opening 10e is formed in the hollow cylindrical portion 10a of the valve body 10, and the end of the second pipe T2 is inserted into the inlet opening 10e and connected by brazing or the like. The axis of the inlet opening 10e is designated as O. The axis O is perpendicular to the axis L.

[0018] The lower end of the can 45 abuts against the upper end of the valve body 10, and the valve body 10 and the can 45 are joined by welding to form a sealed integrated body. A flange-shaped disk 18 is disposed inside the lower end of the can 45 at the upper end of the valve body 10. It is preferable that the flange-shaped disk 18 be welded over its entire circumference at the same time that the valve body 10 and the can 45 are welded together.

[0019] A yoke 51, a bobbin 52, and a stator coil 53 are arranged outside the can 45 to form the stator 50, the outer periphery of which is covered by a resin molded cover 58. In this embodiment, the resin molded cover 58 covers the entire stator 50, including the top of the can 45, but it may also cover only the periphery of the yoke 51. The rotor 30 and the stator 50 constitute a stepping motor.

[0020] The stator coil 53 is connected to an external power supply circuit (not shown) via a substrate CB, a connector CN, and wiring HN. The substrate CB and the connector CN are covered with another resin cover 57. When the stator coil 53 is energized and excited, the rotor 30 disposed within the can 45 can rotate around the axis L. The interior of the resin cover 57 is filled with a molding resin MR.

[0021] The guide stem 15, which is disposed inside the rotor 30, comprises a solid cylindrical main body 15a and a hollow cylindrical portion 15b connected together. An internally threaded hole (internal threaded portion) 15c is formed in the main body 15a, penetrating its center in the direction of the axis L. A flange-shaped disk 18 is fixed to the outer circumferential groove of the expanded diameter portion 15e on the lower end side of the hollow cylindrical portion 15b. As described above, the flange-shaped disk 18 is welded to the upper end of the valve body 10, thereby fixing the guide stem 15 to the valve body 10. A pressure equalizing hole 15d is formed in the hollow cylindrical portion 15b, penetrating from the inner to the outer periphery.

[0022] In order to set the control origin position of the rotor 30 and the valve shaft 21, a valve closing direction fixed stopper 55 having a rectangular cross section is provided to protrude upward from the upper surface of the main body 15a of the guide stem 15, and a valve opening direction fixed stopper 56 having a rectangular cross section is provided to protrude downward from the lower surface of the main body 15a of the guide stem 15. Here, the control origin position of the rotor 30 and the valve shaft 21 refers to the position when the valve closing direction movable stopper 35 abuts against and is locked by the valve closing direction fixed stopper 55, and the rotor 30 and the valve shaft 21 reach their lowest positions.

[0023] The valve stem 21 comprises a small-diameter portion 21a fitted with an annular connector 32 attached to the rotor 30, a male threaded portion 21b that screws into the female threaded hole 15c of the guide stem 15, a valve stem cylindrical portion 21c formed below the male threaded portion 21b, an outer flange portion 21d that extends radially outward from the lower end of the valve stem cylindrical portion 21c, and a small cylindrical portion 21e that protrudes downward from the lower end of the valve stem cylindrical portion 21c. The outer diameter of the small cylindrical portion 21e is smaller than that of the valve stem cylindrical portion 21c.

[0024] A valve closing direction movable stopper 35 is threadedly engaged with the upper end of the male thread portion 21b of the valve shaft 21 and is engaged with the lower surface of the upper wall of the rotor 30. A stopper portion 35a having a rectangular cross section is formed on the lower surface of the valve closing direction movable stopper 35.

[0025] Furthermore, a valve opening direction movable stopper 36 is threadedly engaged with the lower end of the male thread portion 21b of the valve shaft 21 and is engaged with the upper surface of the valve holder 23. A stopper portion 36a having a rectangular cross section is formed on the upper surface of the valve opening direction movable stopper 36.

[0026] In Figure 4, a valve holder 23 is attached to the lower end of the valve stem 21. The valve holder 23 is composed of an outer wall portion 23a and an inner flange portion 23b that extends radially inward from the upper end of the outer wall portion 23a. The outer wall portion 23a has an inner periphery with a larger diameter than the outer flange portion 21d, and the inner flange portion 23b has an inner periphery with a smaller diameter than the outer flange portion 21d. A circular opening 23c that slidably fits onto the valve stem cylindrical portion 21c is formed in the center of the inner flange portion 23b. The outer periphery of the outer wall portion 23a slidably fits onto the inner periphery of the hollow cylindrical portion 15b of the guide stem 15. In addition, a plurality of communication holes 23d that are arranged circumferentially and penetrate radially are formed near the upper end of the outer wall portion 23a.

[0027] The lower end of the outer wall portion 23a is connected to a first valve body (also simply referred to as a valve body) 24. The first valve body 24 is composed of an upper cylindrical portion 24a that is fitted to the outer wall portion 23a and fixed by press-fitting or welding, and a lower cylindrical portion 24b that are connected together. A tapered portion 24c that decreases in diameter as it extends downward is formed at the lower end of the lower cylindrical portion 24b. The first valve body 24 also has a through-hole 24d that penetrates vertically along the axis L. The through-hole 24d communicates between a space on the valve stem side (an intermediate chamber MC above the first valve body 24) and a space on the opposite side of the valve stem (a space below the first valve body 24 that connects to the orifice passage 11d), with a seal holder 29 (described later) sandwiched between them.

[0028] A second valve body 25 is disposed inside the valve holder 23. The second valve body 25 is made of metal (for example, SUS) and has a substantially cylindrical valve body base 25a, a valve body flange portion 25b extending radially outward from the upper end of the valve body base 25a, and a hemispherical portion 25c formed at the lower end of the valve body base 25a and equipped with a spherical surface.

[0029] The coil spring (elastic body) 26 has its upper end abutting against the lower end of the valve body flange portion 25b and its lower end abutting against the upper surface of the first valve body 24, and urges the second valve body 25 in a direction away from the first valve body 24.

[0030] An annular thrust bearing 27 is disposed between the second valve body 25 and the valve shaft 21. The thrust bearing 27 is disposed around the small cylindrical portion 21e of the valve shaft 21 and abuts against the upper surface of the second valve body 25 and the lower surface of the outer flange portion 21d, allowing the second valve body 25 and the valve shaft 21 to rotate relative to each other with low friction.

[0031] In addition, a washer 28, which is an annular plate, is disposed between the outer flange portion 21d of the valve shaft 21 and the inner flange portion 23b of the valve holder 23. The washer 28 also enables the outer flange portion 21d and the inner flange portion 23b to rotate relative to each other with low friction.

[0032] A seal holder 29 is disposed between the valve holder 23 and the hollow cylindrical portion 10a of the valve body 10. The seal holder 29 comprises an annular holder base 29a, an annular holder flange 29b extending radially outward from the upper end of the holder base 29a, and a circular bottom wall 29c shifted from the lower end of the holder base 29a and extending radially outward (connected via a small cylindrical portion). An annular recess 29e is coaxially formed at the upper end of the holder base 29a (radially inside the holder flange 29b). An outer wall 23a of the valve holder 23 slidably fits into a holder opening 29d penetrating the bottom wall 29c, and the outer wall 23a protrudes downward from the valve holder 23.

[0033] The holder flange portion 29b is sandwiched and placed between the upper end of the hollow cylindrical portion 10a and the lower surface of the flange-shaped disk 18, with a gap radially inward from the inner periphery of the end of the can 45, and is welded as described below. The outer periphery of the expanded diameter portion 15e on the lower end side of the guide stem 15 is disposed opposite the inner periphery of the holder flange portion 29b. The tip of the second pipe T2 is disposed in contact with the outer periphery of the bottom wall portion 29c, thereby enabling the insertion position of the second pipe T2 to be determined.

[0034] An O-ring OR and a sliding member SD are disposed on the inner periphery of the holder base 29a, which is sandwiched between the lower end of the guide stem 15 and the bottom wall 29c. The O-ring OR and the sliding member SD form an annular seal. The sliding member SD is a flexible cylindrical body made of a low-friction material such as PTFE, which has a lower friction coefficient than the O-ring OR, and is disposed between the O-ring OR and the outer wall 23a. Therefore, while the holder base 29a and the outer wall 23a can be displaced relative to each other in the direction of the axis L, the O-ring OR and the sliding member SD can seal the fluid. It is also possible to dispose only the O-ring OR without providing the sliding member SD.

[0035] The internal space of the motor-operated valve 1 (the space surrounded by the can 45 and the valve body 10) is divided into a high-pressure valve chamber VC, an intermediate chamber MC in the valve holder 23, and a back pressure chamber BC in the can 45. An O-ring OR and a sliding member SD seal between the valve chamber VC and the intermediate chamber MC.

[0036] Here, when the gap between the outer periphery of the lower end expanded diameter portion (cylindrical fitting portion) 15e and the inner periphery of the annular recess (cylindrical fitted portion) 29e is defined as A, and the gap between the outer periphery of the holder base 29a and the inner periphery of the hollow cylindrical portion 10a of the valve body 10 is defined as B, then B>A holds.

[0037] 1 to 3, in this embodiment, the rotor 30, the valve stem 21, the valve opening direction movable stopper 36, the valve holder 23, the washer 28, the thrust bearing 27, the second valve body 25, the coil spring 26, and the first valve body 24 are displaceable in the direction of the axis L relative to the guide stem 15 and the seal holder 29 fixed to the valve body 10. Furthermore, the valve holder 23 and the first valve body 24 are displaceable in the direction of the axis L relative to the valve stem 21. Furthermore, the second valve body 25 is displaceable in the direction of the axis L relative to the valve stem 21 and the first valve body 24.

[0038] (Motor-operated valve assembly process) The assembly process for the motor-operated valve 1 will now be described. First, the guide stem 15, which has the flanged disk 18 attached, is joined to the seal holder 29, which has the O-ring OR and sliding member SD attached, to create a first assembly. The seal holder 29 may be welded to the flanged disk 18 at this point, or may be welded simultaneously when welding the flanged disk 18 to the valve body 10. This creates a seal between the seal holder 29 and the valve body 10 (i.e., the outer periphery of the holder base 29a and the inner periphery of the valve body 10).

[0039] Furthermore, after assembling the washer 28 and the valve holder 23 from the male thread portion 21b side of the valve shaft 21, the valve opening direction movable stopper 36 is screwed onto the male thread portion 21b and assembled. After that, the thrust bearing 27, the second valve body 25, and the coil spring 26 are placed inside the valve holder 23, and the first valve body 24 is welded to the lower end of the valve holder 23 to produce a second assembly.

[0040] The male threaded portion 21b of the second assembly formed in this manner is screwed into the female threaded hole 15c of the first assembly, and the movable stopper 35 for the valve closing direction is screwed into the male threaded portion 21b protruding from the guide stem 15, and then the rotor 30 is assembled to produce the third assembly.

[0041] Furthermore, the valve seat member 11 is brazed to the valve body 10, and the valve stem 21 of the third assembly and the valve seat member 11 are coaxially positioned using a jig or the like, while the third assembly is housed in the can 45, and the valve body 10, can 45, and flanged disk 18 are fixed by welding. Thereafter, the pipes T1 and T2 are brazed, and the stator 50 is attached to the can 45, completing the motor-operated valve 1.

[0042] 4, according to this embodiment, a gap A (preferably an interference fit) between the outer periphery of the lower-end expanded diameter portion 15e and the inner periphery of the annular recess 29e is smaller than a gap B between the outer periphery of the valve holder 23 and the inner periphery of the hollow cylindrical portion 10a of the valve body 10. This gap B can be used to adjust the valve holder 23 and the first valve body 24 together with the seal holder 29 in a direction perpendicular to the axis, thereby centering the valve stem 21 and the valve seat member 11. Since the coaxiality of the guide stem 15 and the seal holder 29 is ensured by the precision of machining, by installing the seal holder 29 coaxially with the axis L of the valve body 10 (valve seat member 11), the coaxiality of the valve seat 11e and the first valve body 24 can be easily ensured, thereby suppressing fluid leakage.

[0043] (Operation of the motor-operated valve) Next, the operation of the motor-operated valve 1 will be described in detail. First, it is assumed that a fluid (refrigerant) is flowing into the valve chamber VC from the second pipe T2, and the motor-operated valve 1 is in the valve-closed state shown in Fig. 1. At this time, the lower end of the lowered valve stem 21 presses against the upper end of the second valve body 25, causing the second valve body 25 to descend against the biasing force of the coil spring 26, and the hemispherical portion 25c maintains a state in which it closes the upper end of the through-hole 24d. Even if the second valve body 25 is tilted, the hemispherical portion 25c can properly close the upper end of the through-hole 24d.

[0044] Furthermore, the upper end of the first valve body 24 is pressed by the second valve body 25, so that the semispherical portion 25c is seated on the valve seat 11e.

[0045] In the valve closed state, the tapered portion 24c is seated on the valve seat 11e, thereby preventing fluid from flowing out from the valve chamber VC into the first pipe T1. Even if fluid moves from the valve chamber VC to the intermediate chamber MC and the pressure in the intermediate chamber MC increases, the hemispherical portion 25c closes the upper end of the through-hole 24d, thereby preventing fluid from flowing out from the intermediate chamber MC into the first pipe T1. In this state, the pressure of the valve chamber VC acts above the first valve body 24, and the pressure of the first pipe T1 acts below the first valve body 24, so that the first valve body 24 is stably seated on the valve seat 11e.

[0046] When pulsed power is supplied to the stator 50 from an external power supply circuit in this closed valve state, the rotor 30 and the valve shaft 21 are driven to rotate in one direction, and accordingly, the valve shaft 21 and the valve holder 23 are raised while rotating via the screw feed mechanism consisting of the female threaded hole 15c and the male threaded portion 21b.

[0047] As the valve stem 21 rises, the pressing force urging the second valve body 25 downward disappears, and as shown in Fig. 2, the second valve body 25 moves away from the first valve body 24 due to the urging force of the coil spring 26. Then, the fluid in the intermediate chamber MC flows through the through-hole 24d and the orifice passage 11d to the first pipe T1 side, and the pressure in the intermediate chamber MC decreases to approach the pressure in the first pipe T1. As a result, the pressures above and below the valve seat 11e are balanced (the pressure difference between the above and below is canceled), and the first valve body 24 tends to rise.

[0048] As the valve stem 21 rises, the outer flange 21d also rises, urging the inner flange 23b upward via the washer 28. This causes the valve holder 23 to rise in a lifted manner, separating the first valve body 24 from the valve seat 11e and achieving the fully open state shown in Figure 3. As the valve holder 23 rises, it slides against the sliding member SD, which is urged radially inward by the resilient force of the O-ring OR, ensuring long-term wear resistance and sealing performance. Furthermore, the washer 28 slides against the outer flange 21d and the inner flange 23b as they rotate relative to each other, ensuring a low-friction state.

[0049] When the valve stem 21 rises to a predetermined position, the movable stopper 36 for the valve opening direction abuts and engages with the fixed stopper 56 for the valve opening direction, thereby forcibly stopping the rotation and rise of the rotor 30, valve stem 21, and valve holder 23.

[0050] When the first valve body 24 moves away from the valve seat 11e, the fluid that has flowed into the valve chest VC from the second pipe T2 flows out to the first pipe T1 side via the valve seat 11e and the orifice passage 11d. The flow rate of the outflowing fluid is determined by the gap between the tapered portion 24c and the valve seat 11e.

[0051] At this time, the intermediate chamber MC communicates with the valve chamber VC via the through-hole 24d, so the pressure in the intermediate chamber MC is approximately equal to the pressure in the valve chamber VC. In addition, the intermediate chamber MC communicates with the back pressure chamber BC via the communication hole 23d of the valve holder 23 and the pressure equalizing hole 15d of the guide stem 15, so the pressure in the intermediate chamber MC and the pressure in the back pressure chamber BC are approximately equal.

[0052] On the other hand, when a pulse of reverse characteristics is supplied to the stator 50 from an external power supply circuit in this fully open state, the rotor 30 and the valve shaft 21 are driven to rotate in the other direction, and the valve shaft 21 and the valve holder 23 are lowered while rotating via the screw feed mechanism consisting of the female threaded hole 15c and the male threaded portion 21b.

[0053] As the valve stem 21 descends, the outer flange portion 21d also descends, which causes the valve holder 23 to descend, and the first valve body 24 seats on the valve seat 11e, thereby preventing fluid from passing between the first valve body 24 and the valve seat 11e from the valve chamber VC.

[0054] Furthermore, after the first valve body 24 is seated on the valve seat 11e, the second valve body 25 is pressed downward by the lower end of the valve stem 21 and displaced against the biasing force of the coil spring 26, and the lower end of the second valve body 25 abuts against the upper end of the first valve body 24. When the lower end of the second valve body 25 abuts against the upper end of the first valve body 24, a frictional force is generated between them, so that the rotation of the second valve body 25 is forcibly stopped, while the rotation of the valve stem 21 continues. At this time, the thrust bearing 27 slides against the valve stem 21 and the second valve body 25 as they rotate relative to each other, ensuring a low-friction state.

[0055] The second valve body 25 closes the upper end of the through-hole 24d, thereby preventing the fluid from flowing out from the intermediate chamber MC toward the first pipe T1.

[0056] When the valve stem 21 descends to a predetermined position, the movable stopper 35 for the valve closing direction abuts and engages with the fixed stopper 55 for the valve closing direction, and the rotor 30 and valve stem 21 reach their lowest positions. Even if pulsed power supply to the stator 50 continues, the descent of the rotor 30 and valve stem 21 is forcibly stopped.

[0057] According to this embodiment, when the valve is closed, the first valve body 24 is seated on the valve seat 11e and the second valve body 25 closes the through hole 24d of the first valve body 24, so that leakage of fluid from the valve chest VC to the orifice passage 11d can be suppressed when the valve is closed, regardless of the tension of the O-ring OR, the effects of thermal deterioration, etc. This allows the use of an O-ring OR with a relatively low tension, thereby reducing the sliding resistance of the O-ring OR, thereby reducing the motor load when the valve stem 21 is displaced and increasing the freedom of selection of the O-ring OR.

[0058] If fluid leakage occurs from the O-ring OR or the sliding member SD when the valve is closed, the fluid in the valve chamber VC will move from the communicating hole 23d to the intermediate chamber MC, causing the pressure in the intermediate chamber MC to become equal to the pressure in the valve chamber VC. Therefore, a differential pressure between the pressure in the through-hole 24d (low pressure) and the pressure in the intermediate chamber MC (high pressure) will act on the second valve body 25. However, when the valve is opened, the second valve body 25 first opens the through-hole 24d, causing the fluid in the intermediate chamber MC to move through the through-hole 24d toward the orifice passage 11d in the valve seat member 11. Therefore, the fluid pressures above and below the first valve body 24 are balanced, and the first valve body 24 then opens smoothly.

[0059] In this embodiment, the O-ring OR and the sliding member SD are disposed radially outside the valve holder 23 via the seal holder 29 fixed to the valve body 10, allowing their diameters to be relatively large. This makes it possible to suppress variations in the tension force of the O-ring OR, and also makes it less likely that damage will occur to the O-ring OR and the sliding member SD even if an excessive differential pressure is applied to them.

[0060] The present invention is not limited to the above embodiments. For example, although the second valve body is formed from a cylindrical member having a semi-spherical portion formed at its end, the second valve body may be formed by fastening a spherical body to the end of a cylindrical member.

[0061] This specification includes the disclosure of the following inventions. (First aspect) a valve body having a valve seat; a valve shaft that moves in the direction of the rotation axis as the motor rotates; a guide stem attached to the valve body and having a threaded portion that screws into a thread formed on the valve stem side; a valve holder held by the valve stem; a valve body fixed to the valve seat side of the valve holder; a seal holder that seals between an outer periphery of the valve holder and an inner periphery of the valve body, the valve body has a through hole that penetrates in the rotation axis direction and can be opened and closed, An electrically operated valve, characterized in that an annular seal body is disposed between the inner periphery of the seal holder and the outer periphery of the valve holder.

[0062] (Second aspect) The annular seal body is composed of an O-ring arranged on the seal holder side and a sliding member arranged on the valve holder side, the sliding member having a friction coefficient smaller than that of the O-ring. The motor-operated valve according to the first aspect,

[0063] (Third aspect) The seal holder has a holder flange portion extending radially outward, and the holder flange portion is fixed to an end portion of the valve body. The motor-operated valve according to the first or second aspect,

[0064] (Fourth aspect) an end of a can in which a rotor of the motor is housed is fixed to an end of the valve body, and an outer edge of the holder flange portion is fixed to the can with a gap therebetween; The motor-operated valve according to a third aspect,

[0065] (Fifth aspect) A fitting portion into which the guide stem is fitted is formed on the radially inner side of the holder flange portion. The motor-operated valve according to the third or fourth aspect,

[0066] (Sixth aspect) a tip of a pipe inserted into the valve body along a direction intersecting the axis of the valve body abuts against the seal holder; The motor-operated valve according to any one of the first to fifth aspects, characterized in that: [Explanation of symbols]

[0067] 1. Motor-operated valve 10 Valve body 11 Valve seat member 11e Valve seat 15 Guide stem 21 Valve stem 23 Valve holder 24 First valve body 25 Second valve body 26 Coil spring 27 Thrust bearing 28 Washer 29 Seal holder 30 rotors 35 Movable stopper for closing valve direction 36 Movable stopper for valve opening direction 50 Stator 53 Stator coil 55 Fixed stopper for closing valve direction 56 Valve opening direction fixed stopper BC back pressure chamber MC intermediate room VC valve chamber OR O-ring SD sliding member

Claims

1. a valve body having a valve seat; a valve shaft that moves in the direction of the rotation axis as the motor rotates; a guide stem attached to the valve body and having a threaded portion that screws into a thread formed on the valve stem side; a valve holder held by the valve stem; a valve body fixed to the valve seat side of the valve holder; a seal holder that seals between an outer periphery of the valve holder and an inner periphery of the valve body, the valve body has a through hole that penetrates in the direction of the rotation axis and that can be opened and closed, An annular seal is disposed between the inner periphery of the seal holder and the outer periphery of the valve holder. A motor-operated valve characterized by:

2. The annular seal body is composed of an O-ring arranged on the seal holder side and a sliding member arranged on the valve holder side, the sliding member having a smaller friction coefficient than the O-ring.

2. The motor-operated valve according to claim 1.

3. The seal holder has a holder flange portion extending radially outward, and the holder flange portion is fixed to an end portion of the valve body.

2. The motor-operated valve according to claim 1.

4. an end of a can in which a rotor of the motor is housed is fixed to an end of the valve body, and an outer edge of the holder flange portion is fixed to the can with a gap therebetween; 4. The motor-operated valve according to claim 3.

5. A fitting portion into which the guide stem is fitted is formed on the radially inner side of the holder flange portion.

4. The motor-operated valve according to claim 3.

6. a tip of a pipe inserted into the valve body along a direction intersecting the axis of the valve body abuts against the seal holder; 2. The motor-operated valve according to claim 1.

Images