JP7761950B2 - Electric valve - Google Patents

Description

The present invention relates to an electrically operated valve.

A motor-driven electric valve has a screw mechanism in which the male thread of the valve shaft, which is driven to rotate by a stepping motor, is threaded into a female threaded hole in the valve body. This screw mechanism rotates the valve shaft 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.

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

JP 2013-130271 A

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

The present invention aims to provide an electrically operated valve that can be assembled relatively easily yet suppresses fluid leakage, etc.

The motor-operated valve of the present invention comprises:
a valve body having a valve seat;
a valve stem having a male thread portion and driven to rotate by a motor;
a guide stem attached to the valve body, the guide stem including a female threaded portion that screws into the male threaded portion and a cylindrical fitting portion;
a valve holder held by the valve stem;
a valve body fixed to the valve holder and movable toward and away from the valve seat;
a seal holder including a cylindrical fitted portion into which the fitting portion is fitted and a cylindrical holder base, the holder base being disposed within the valve body;
the valve body has an openable and closable through-hole that connects a space on the valve stem side with a space on the opposite side of the valve stem across the holder base,
a seal is formed between the outer periphery of the holder base and the inner periphery of the valve body;
an annular seal is disposed between an inner periphery of the holder base and an outer periphery of the valve holder;
a radial gap A between the fitting portion and the fitted portion is smaller than a gap B between an outer periphery of the holder base and an inner periphery of the valve body;
It is characterized by:

The present invention provides an electrically operated valve that is relatively easy to assemble yet can suppress fluid leakage, etc.

FIG. 1 is a longitudinal cross-sectional view showing an electric valve according to an embodiment of the present invention, in a closed state. FIG. 2 is a vertical cross-sectional view showing the motor-operated valve according to the embodiment of the present invention, in a partially open state. 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. FIG. 4 is an enlarged view of the vicinity of the valve chamber of the motor-operated valve shown in FIG.

Embodiments of the present invention will be described below with reference to the drawings.

Figures 1 to 3 are longitudinal cross-sectional views showing a motor-operated valve 1 according to an embodiment of the present invention. Figure 4 is an enlarged view of the valve chamber and its surroundings in 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.

(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 integrally rotatable, 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.

The valve body 10 consists of a hollow cylindrical portion 10a and a bottom wall portion 10b connected together. The thicknesses of the hollow cylindrical portion 10a and the bottom wall portion 10b are approximately equal. The inside of the hollow cylindrical portion 10a forms the valve chamber VC.

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. In this case, the valve seat member 11 constitutes part of the valve body 10.

The valve seat member 11 consists 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 by brazing or the like.

In Figure 4, the valve seat member 11 has a cylindrical upper opening 11c from the upper end, a tapered middle opening 11f that narrows in diameter as it extends downward, and a cylindrical orifice passage 11d with a smaller diameter than the upper opening 11c. The first pipe T1 is positioned so that it abuts 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 that widens in diameter as it extends upward is formed on the inner periphery of the upper end of the upper opening 11c.

In Figures 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 O. The axis O is perpendicular to the axis L.

The lower end of the can 45 abuts against the upper end of the valve body 10, and the valve body 10 and can 45 are joined by welding, forming a sealed, integrated unit. Furthermore, a flange-shaped disk 18 is positioned 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 around its entire circumference at the same time that the valve body 10 and can 45 are welded together.

A yoke 51, bobbin 52, and 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 stator 50 form a stepping motor.

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

The guide stem 15, located inside the rotor 30, consists of a solid cylindrical main body 15a and a hollow cylindrical portion 15b connected together. The main body 15a has a female threaded hole (female threaded portion) 15c that penetrates 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 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 the inner and outer periphery.

In addition, to set the control origin position of the rotor 30 and valve shaft 21, a valve closing direction fixed stopper 55 with a rectangular cross section protrudes upward from the upper surface of the main body 15a of the guide stem 15, and a valve opening direction fixed stopper 56 with a rectangular cross section protrudes 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 valve shaft 21 refers to the position when the valve closing direction movable stopper 35 abuts and engages with the valve closing direction fixed stopper 55, and the rotor 30 and valve shaft 21 reach their lowest position.

The valve stem 21 is composed of a small-diameter portion 21a fitted with an annular connector 32 attached to the rotor 30, a male threaded portion 21b that threads 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 the outer diameter of the valve stem cylindrical portion 21c.

A valve-closing direction movable stopper 35 is threadedly engaged with the upper end of the male threaded portion 21b of the valve shaft 21 and is engaged with the underside of the upper wall of the rotor 30. A stopper portion 35a with a rectangular cross section is formed on the underside of the valve-closing direction movable stopper 35.

In addition, a valve opening direction movable stopper 36 is threadedly engaged with the lower end of the male threaded portion 21b of the valve shaft 21 and is engaged with the upper surface of the valve holder 23. A stopper portion 36a with a rectangular cross section is formed on the upper surface of the valve opening direction movable stopper 36.

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, while the inner flange portion 23b has an inner periphery with a smaller diameter than the outer flange portion 21d. A circular opening 23c is formed in the center of the inner flange portion 23b, which slidably fits onto the valve stem cylindrical portion 21c. 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, multiple communication holes 23d that are arranged circumferentially and penetrate radially are formed near the upper end of the outer wall portion 23a.

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

A second valve body 25 is disposed inside the valve holder 23. The second valve body 25 is made of metal (e.g., 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 with a spherical surface formed at the lower end of the valve body base 25a.

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

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.

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.

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 extending radially outward from the lower end of the holder base 29a (connected via a small cylindrical portion). An annular recess 29e is coaxially formed at the upper end of the holder base 29a (radially inward of the holder flange 29b). The outer wall 23a of the valve holder 23 slidably fits into a holder opening 29d that penetrates the bottom wall 29c, and the outer wall 23a protrudes downward from the valve holder 23.

The holder flange portion 29b is sandwiched and placed between the upper end of the hollow cylindrical portion 10a and the underside 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 of the guide stem 15 is positioned opposite the inner periphery of the holder flange portion 29b. The tip of the second piping T2 is positioned in contact with the outer periphery of the bottom wall portion 29c, thereby allowing the insertion position of the second piping T2 to be determined.

An O-ring OR and sliding member SD are placed 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 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 coefficient of friction than the O-ring OR, and is placed between the O-ring OR and the outer wall 23a. Therefore, while the holder base 29a and the outer wall 23a can move relative to each other in the direction of the axis L, the O-ring OR and sliding member SD can seal the fluid. It is also possible to place only the O-ring OR without providing the sliding member SD.

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

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.

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

(Motor-operated valve assembly process)
The assembly process for the motor-operated valve 1 will now be described. First, the guide stem 15, to which the flanged disk 18 is attached, is joined to the seal holder 29, to which the O-ring OR and sliding member SD are attached, to create a first assembly. The seal holder 29 may be welded to the flanged disk 18 at this stage, or may be welded simultaneously when the flanged disk 18 is welded 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).

The washer 28 and valve holder 23 are then attached to the male threaded portion 21b of the valve shaft 21, and the valve opening direction movable stopper 36 is then screwed onto the male threaded portion 21b and assembled. The thrust bearing 27, second valve body 25, and coil spring 26 are then placed inside the valve holder 23, and the first valve body 24 is welded to the lower end of the valve holder 23 to create the second assembly.

The male threaded portion 21b of the second assembly formed in this way is threaded into the female threaded hole 15c of the first assembly, and the movable valve closing stopper 35 is threaded into the male threaded portion 21b protruding from the guide stem 15. The rotor 30 is then attached to create the third assembly.

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. The third assembly is then placed inside the can 45, and the valve body 10, can 45, and flanged disk 18 are fixed together by welding. After that, the pipes T1 and T2 are brazed, and the stator 50 is attached to the can 45, completing the motor-operated valve 1.

In this embodiment, as shown in FIG. 4, the 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 the 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 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 the machining process, installing the seal holder 29 coaxially with the axis L of the valve body 10 (valve seat member 11) easily ensures the coaxiality of the valve seat 11e and the first valve body 24, thereby suppressing fluid leakage.

(Operation of the motor-operated valve)
Next, the operation of the motor-operated valve 1 will be described in detail.
First, assume that a fluid (refrigerant) is flowing into the valve chamber VC from the second pipe T2, and that the motor-operated valve 1 is in the 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 still properly close the upper end of the through-hole 24d.

In addition, the second valve body 25 presses the upper end of the first valve body 24, causing the hemispherical portion 25c to seat on the valve seat 11e.

In the closed valve state, the tapered portion 24c seats on the valve seat 11e, 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, 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 the first valve body 24 seats stably on the valve seat 11e.

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

As the valve stem 21 rises, the downward pressing force on the second valve body 25 disappears, and as shown in FIG. 2, the second valve body 25 moves away from the first valve body 24 due to the biasing force of the coil spring 26. As a result, the fluid in the intermediate chamber MC flows out through the through-hole 24d and the orifice passage 11d toward the first pipe T1, causing the pressure in the intermediate chamber MC to decrease toward the pressure in the first pipe T1. This balances the pressures above and below the valve seat 11e (the pressure difference between the top and bottom is canceled), making it easier for the first valve body 24 to rise.

As the valve stem 21 rises, the outer flange portion 21d also rises, urging the inner flange portion 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 valve 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 elastic force of the O-ring OR, ensuring long-term wear resistance and sealing performance. Furthermore, the washer 28 slides against the outer flange portion 21d and the inner flange portion 23b as they rotate relative to each other, ensuring a low-friction state.

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

When the first valve body 24 moves away from the valve seat 11e, the fluid that has flowed into the valve chamber VC from the second pipe T2 flows out to the first pipe T1 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.

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. Furthermore, the intermediate chamber MC is also connected to 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.

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

As the valve stem 21 descends, the outer flange portion 21d also descends, causing the valve holder 23 to descend, and the first valve body 24 seats on the valve seat 11e. This prevents fluid from passing between the first valve body 24 and the valve seat 11e from the valve chamber VC.

Furthermore, after the first valve body 24 seats on the valve seat 11e, the lower end of the valve stem 21 presses the second valve body 25 downward, displacing it 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 the two, forcing the rotation of the second valve body 25 to a halt, while the rotation of the valve stem 21 continues. At this time, the thrust bearing 27 slides against the valve stem 21 and second valve body 25 as they rotate relative to each other, ensuring a low-friction state.

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

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

In this embodiment, when the valve is closed, the first valve body 24 seats on the valve seat 11e and the second valve body 25 closes the through-hole 24d of the first valve body 24. This prevents fluid from leaking from the valve chamber VC to the orifice passage 11d when the valve is closed, regardless of the tension of the O-ring OR or the effects of thermal degradation. 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 choice for the O-ring OR.

If fluid leakage occurs from the O-ring OR or sliding member SD when the valve is closed, the fluid in the valve chamber VC will move from the communication 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, the second valve body 25 will be subjected to a pressure difference between the pressure in the through-hole 24d (low pressure) and the pressure in the intermediate chamber MC (high pressure). 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 subsequently opens smoothly.

In this embodiment, the O-ring OR and sliding member SD are positioned radially outward of the valve holder 23 via the seal holder 29 fixed to the valve body 10, allowing their diameters to be relatively large. This reduces variation in the tension force of the O-ring OR, and also makes them less susceptible to damage even when an excessive differential pressure is applied to the O-ring OR and sliding member SD.

The present invention is not limited to the above embodiments. For example, the second valve body was constructed from a cylindrical member with a hemispherical portion formed at the end, but the second valve body may also be constructed by fastening a spherical body to the end of a cylindrical member.

This specification includes the disclosure of the following inventions.
(First Aspect)
a valve body having a valve seat;
a valve stem having a male thread portion and driven to rotate by a motor;
a guide stem attached to the valve body, the guide stem including a female threaded portion that screws into the male threaded portion and a cylindrical fitting portion;
a valve holder held by the valve stem;
a valve body fixed to the valve holder and movable toward and away from the valve seat;
a seal holder including a cylindrical fitted portion into which the fitting portion is fitted and a cylindrical holder base, the holder base being disposed within the valve body;
the valve body has an openable and closable through-hole that connects a space on the valve stem side with a space on the opposite side of the valve stem across the holder base,
a seal is formed between the outer periphery of the holder base and the inner periphery of the valve body;
an annular seal is disposed between an inner periphery of the holder base and an outer periphery of the valve holder;
a radial gap A between the fitting portion and the fitted portion is smaller than a gap B between an outer periphery of the holder base and an inner periphery of the valve body;
A motor-operated valve characterized by:

(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 smaller friction coefficient than the O-ring.
The motor-operated valve according to the first aspect,

(Third Aspect)
The seal holder has a holder flange portion extending radially outward from the holder base portion, 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,

(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,

(Fifth Aspect)
The fitted portion is formed on the radially inner side of the holder flange portion.
The motor-operated valve according to the third or fourth aspect,

(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,

(Seventh aspect)
The fitting portion and the fitted portion are fitted together in an interference fit relationship.
The motor-operated valve according to any one of the first to sixth aspects,

1 Motor-operated valve 10 Valve body 11 Valve seat member 11e Valve seat 15 Guide stem 21 Valve shaft 23 Valve holder 24 First valve body 25 Second valve body 26 Coil spring 27 Thrust bearing 28 Washer 29 Seal holder 30 Rotor 35 Movable stopper for closing valve direction 36 Movable stopper for opening valve direction 50 Stator 53 Stator coil 55 Fixed stopper for closing valve direction 56 Fixed stopper for opening valve direction BC Back pressure chamber MC Intermediate chamber VC Valve chest OR O-ring SD Sliding member

Claims (7)

a valve body having a valve seat;
a valve stem having a male thread portion and driven to rotate by a motor;
a guide stem attached to the valve body, the guide stem including a female threaded portion that screws into the male threaded portion and a cylindrical fitting portion;
a valve holder held by the valve stem;
a valve body fixed to the valve holder and movable toward and away from the valve seat;
a seal holder including a cylindrical fitted portion into which the fitting portion is fitted and a cylindrical holder base, the holder base being disposed within the valve body;
the valve body has an openable and closable through-hole that connects a space on the valve stem side with a space on the opposite side of the valve stem across the holder base,
a seal is formed between the outer periphery of the holder base and the inner periphery of the valve body;
an annular seal is disposed between an inner periphery of the holder base and an outer periphery of the valve holder;
a radial gap A between the fitting portion and the fitted portion is smaller than a gap B between an outer periphery of the holder base and an inner periphery of the valve body;
A motor-operated valve characterized by: 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. The seal holder has a holder flange portion extending radially outward from the holder base portion, and the holder flange portion is fixed to an end portion of the valve body.
2. The motor-operated valve according to claim 1. 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. The fitted portion is formed on the radially inner side of the holder flange portion.
4. The motor-operated valve according to claim 3. 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. The fitting portion and the fitted portion are fitted together in an interference fit relationship.
2. The motor-operated valve according to claim 1.