Shut-off valve

Abstract

The objective is to provide a shut-off valve that employs a screw-feed mechanism as the driving means for the shut-off valve, thereby improving the durability and sealing performance of the valve body sealing surface and the valve seat sealing surface, and thereby improving reliability. [Solution] A shut-off valve comprising a drive shaft 30 movable by a screw feed mechanism, a valve seat portion 10a, a valve body portion 40 having a valve body 42, a valve support 41, a spring receiving portion 45 and a compression spring 46, a rotation suppression means for suppressing the transmission of rotation of the drive shaft 30 to the valve body 42, and a pressing force adjustment shut-off means for adjusting the pressing force of the valve body 42 on the valve seat portion 10a to shut off the flow path, wherein the rotation suppression means is configured such that when the valve body 42 is seated on the valve seat portion 10a, the valve body 42 is loosely fitted and supported with respect to the valve support 41, and the pressing force adjustment shut-off means is configured such that when the valve body 42 is seated on the valve seat portion 10a, the valve body sealing surface 42a is seated flush with the valve seat sealing surface 10aa due to the weight of the valve body 42, resulting in a self-weight seating state.

Description

TECHNICAL FIELD

[0001] The present invention relates to a shutoff valve provided with a rotation restraining means and a pressing force adjustment shutoff means.

BACKGROUND ART

[0002] As a drive means for a shutoff valve, there is a type that employs a solenoid to improve the responsiveness of the valve opening and closing operation, but energization of the solenoid is required to maintain either the valve open state or the valve closed state. For this reason, when this shutoff valve is actually used, the running cost is relatively high, and in the event of a power failure or the like, there is a risk that the function of the valve will be temporarily lost. In order to solve this problem, some shutoff valves employ a screw feed mechanism as the drive means.

[0003] For example, Patent Document 1, as shown in Figure 11, describes a shutoff valve 1100 (hereinafter referred to as "conventional shutoff valve") that is provided with a manifold 1110, a support member 1120 fitted and fixed to the manifold 1110, a drive shaft 1130 supported by the support member 1120 so as to be rotatable and movable in the direction of axis L, a valve body portion 1140 fixed to one end of the drive shaft 1130, a gear motor 1160 that rotates the drive shaft 1130 via a drive sleeve 1131, and a case 1161 fixed to the manifold 1110 and accommodating the gear motor 1160. This manifold 1110 has an inlet flow path 1101, an outlet flow path 1102, a valve chamber 1112, and a valve seat 1110aa provided at the boundary between the valve chamber 1112 and the outlet flow path 1102. Further, the valve body portion 1140 has a valve support portion 1141 that clamps one end of the drive shaft 1130 in the direction of axis L, and a valve body 1142 having a disc-shaped valve body sealing surface.

[0004] Furthermore, although Patent Document 1 does not describe a specific drive mechanism between the support member 1120 and the drive shaft 1130, it is conceivable that a screw feed mechanism may be employed as an example. This screw feed mechanism allows the drive shaft 1130 to move in the axial direction L while rotating together with the valve body 1140 by screwing together the female thread and male thread formed on the inner circumferential surface of the other end of the support member 1120 and the outer circumferential surface of the other end of the drive shaft 1130.

[0005] In such conventional shut-off valves 1100, when the valve body 1142 seats on the valve seat 1110aa, the valve body 1142 rotates together with the drive shaft 1130 and is pressed against the valve seat 1110aa while rotating, resulting in a problem of extremely large wear on the sealing surfaces of both the valve body 1142 and the valve seat 1110aa (hereinafter referred to as "Conventional Problem 1 (Wear due to rotation and pressing against the valve body during seating)").

[0006] In addition, similar to general shut-off valves, the conventional shut-off valve 1100 also has assembly errors to some extent because the drive shaft 1130 and valve body 1140 are connected to the manifold 1110 via a support member 1120. Therefore, in the conventional shut-off valve 1100, when the valve body 1142 seats on the valve seat 1110aa, the valve body sealing surface and the valve seat sealing surface are not perfectly flush with each other but are tilted relative to each other, resulting in a problem of reduced sealing performance (hereinafter referred to as "Conventional Problem 2 (Reduced sealing performance due to tilt of valve body sealing surface and valve seat sealing surface)"). [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Chinese Patent Application Publication No. 114233914 Specification [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] The object of the present invention is to provide a shut-off valve that employs a screw feed mechanism as a driving means for the shut-off valve, and which can improve reliability by focusing particularly on the seating position, thereby improving the durability and sealing performance of the valve body sealing surface and the valve seat sealing surface. [Means for solving the problem]

[0009] To solve the above problem, a screw feed mechanism provides a drive shaft that can move axially with rotation, a valve seat having an annular valve seat sealing surface on the other end, a valve body comprising a valve body having a disc-shaped valve body sealing surface on one end, a cylindrical guide portion and a support portion for supporting the valve body, a spring receiving portion housed in the guide portion and capable of contacting one end of the drive shaft, and a compression spring sandwiched between the spring receiving portion and the support portion, and the rotation of the drive shaft is as The shut-off valve comprises a rotation suppression means for suppressing transmission to the valve body, and a pressing force adjustment shut-off means for adjusting the pressing force of the valve body against the valve seat and shutting off the flow path, wherein the rotation suppression means is configured such that when the valve body seats on the valve seat, the valve body is loosely fitted and supported with respect to the support portion of the valve support, and the pressing force adjustment shut-off means is configured such that when the valve body seats on the valve seat, the valve body seal surface is seated flush with the valve seat seal surface due to the weight of the valve body.

[0010] Furthermore, the shut-off valve described above may further have a configuration in which, when the valve body sealing surface is seated flush with the valve seat sealing surface, one end of the drive shaft presses against the spring receiving portion against the biasing force of the compression spring, thereby causing the valve body sealing surface to be pressed against the valve seat sealing surface via the axial contact portion of the support portion of the valve body and the valve support.

[0011] Furthermore, the shut-off valve described above may further have a configuration in which the pressing force adjustment shut-off means enters an additional self-weight seating state simultaneously with the biased seating state, or between the self-weight seating state and the biased seating state, in which the valve body sealing surface is seated flush with the valve seat sealing surface due to the self-weight of the valve body and the valve support.

[0012] Furthermore, in the above-mentioned shut-off valve, the rotation suppression means may further have a configuration in which, in the biased seated state, one end of the drive shaft is not clamped axially by the valve body.

[0013] Furthermore, in the above-mentioned shut-off valve, the rotation suppression means may further have a configuration in which the valve support is loosely fitted and supported with respect to one end of the drive shaft when the valve body is seated on the valve seat.

[0014] Furthermore, in the above-mentioned shut-off valve, when the valve body is suspended in a state in which it is loosely fitted and supported with respect to the support portion of the valve support, the axial gap on one side between the valve body and the support portion may be set to be larger than the axial screw play of the drive shaft.

[0015] Furthermore, in the above-mentioned shut-off valve, the valve support is loosely fitted and supported on one end of the drive shaft, and the valve body is loosely fitted and supported on the support portion of the valve support in a suspended state, the axial gap on one side between the valve body and the support portion may be set to be larger than the axial gap on the other side between the valve support and one end of the drive shaft.

[0016] Furthermore, in the above-mentioned shut-off valve, either the valve body sealing surface or the valve seat sealing surface may be made of a resin material, and the other may be made of a metal material.

[0017] Furthermore, the above-mentioned shut-off valve may be further provided with a flow straightening means consisting of a projection or recess extending along the axis on the valve body sealing surface. [Effects of the Invention]

[0018] According to the present invention, in a shutoff valve that employs a screw feed mechanism as drive means therefor, particularly focusing on the time of seating, it is possible to provide a shutoff valve that can improve the durability and sealing performance of the valve body sealing surface and the valve seat sealing surface, and can enhance reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] [Figure 1] It is a longitudinal sectional view showing the electric shutoff valve according to the first embodiment of the present invention. [Figure 2] It is a partially enlarged view of the region surrounded by the broken line II shown in FIG. 1. [Figure 3] It is an explanatory diagram of the valve closing operation of the electric shutoff valve shown in FIG. 2, where (a) represents a suspended state, (b) represents a self-weight seating state, (c) represents a transition state, and (d) represents an additional self-weight seating state and a biasing seating state, respectively. [Figure 4] It is an explanatory diagram of the valve closing operation of the electric shutoff valve in a state where the valve support body shown in FIG. 3 is inclined relative to the axis, where (a) represents a partially seated state, and (b) represents a self-weight seating state, respectively. [Figure 5] It is an explanatory diagram (suspended state) of Valve Body Modifications 1 to 4 in the first embodiment, where (a) represents Valve Body Modification 1 (frustoconical protrusion), (b) represents Valve Body Modification 2 (cylindrical protrusion), (c) represents Valve Body Modification 3 (conical recess), and (d) represents Valve Body Modification 4 (cylindrical recess), respectively. [Figure 6] It is a longitudinal sectional view (corresponding to FIG. 2) showing the electric shutoff valve according to the second embodiment. [Figure 7] It is an explanatory diagram of the valve closing operation of the electric shutoff valve shown in FIG. 6, where (a) represents a suspended state, (b) represents a self-weight seating state, (c) represents an additional self-weight seating state, and (d) represents a biasing seating state, respectively. [Figure 8] It is an explanatory diagram of the valve closing operation of the electric shutoff valve in a state where the valve support body shown in FIG. 7 is inclined relative to the axis, where (a) represents a self-weight seating state, and (b) represents an additional self-weight seating state, respectively. [Figure 9] It is a longitudinal sectional view (corresponding to FIG. 6) showing the electric shutoff valve according to the third embodiment. [Figure 10] It is an explanatory diagram of the valve closing operation of the electric shutoff valve shown in Figure 9, wherein (a) represents the suspended state, (b) represents the self-weight seating state, (c) represents the additional self-weight seating state, and (d) represents the biased seating state, respectively. [Figure 11] It is a longitudinal sectional view showing a shutoff valve according to the prior art. [Mode for Carrying Out the Invention]

[0020] Embodiments of the present invention will be described in detail with reference to Figures 1 to 10. In the following, an electric shutoff valve will be described, but the rotation restraining means and the pressing force adjusting shutoff means of the present invention are not limited to electric shutoff valves, and may be applied to all types of shutoff valves such as manual shutoff valves, for example.

[0021] <Regarding Terms> In this specification and the claims, “left,” “right,” “up,” and “down” refer to the directions shown in Figures 1 to 10. In this specification and the claims, “one end” and “the other end” refer to the “lower end” and “upper end” in the drawings. In this specification and the claims, “rotation suppression means” refers to a means that suppresses the transmission of rotation of the drive shaft to the valve body. In this specification and the claims, “pressure adjustment shutoff means” refers to a means that adjusts the pressure of the valve body on the valve seat to shut off the flow path. In this specification and the claims, “loosely fitted support” refers to a state in which two members are fitted together with some play, and there is a gap between these two members that allows relative movement in the radial and axial directions. In this specification and the claims, “suspended state” refers to a state in which the valve body is suspended from the support portion of the valve support, or the valve support is suspended from one end of the drive shaft. In this specification and the claims, “self-weight seating state” means that when the valve body is seated on the valve seat, the valve body is loosely supported and the valve body sealing surface is seated flush with the valve seat sealing surface due to the weight of the valve body. In this specification and the claims, “additional self-weight seating state” means that the valve support is loosely supported and the valve body sealing surface is seated flush with the valve seat sealing surface due to the weight of the valve body and the valve support. In this specification and the claims, “biased seating state” means that in a state where the valve body sealing surface is seated flush with the valve seat sealing surface, the valve body sealing surface is pressed against the valve seat sealing surface by the biasing force of the compression coil spring. In this specification and the claims, "disc-shaped valve sealing surface" refers to a valve having a disc-shaped sealing surface when viewed from the axial direction, and includes a disc-shaped valve sealing surface in addition to a flat disc-shaped valve sealing surface, in which a projection or recess extending along the axis is formed.

[0022] (First embodiment) <Regarding the configuration of the electric shut-off valve> An electric shut-off valve 100a according to the first embodiment of the present invention will be described with reference to Figures 1 and 2. The electric shut-off valve 100a mainly consists of a valve body 10, a support member 20, a drive shaft 30, a valve body 40, a coil member 50, and a stepping motor 60. The components of the electric shut-off valve 100a will be described in order below. As will be described in detail later, the electric shut-off valve 100a of the first embodiment simultaneously employs a rotation suppression means (1) (the valve body is loosely fitted and supported with respect to the support member) and a pressing force adjustment shut-off means (1) (self-weight seating state), thereby simultaneously resolving conventional problems 1 (wear due to pressing on the valve body and accompanying rotation when seating) and conventional problems 2 (reduced sealing performance due to inclination of the valve body sealing surface and valve seat sealing surface), and improving reliability.

[0023] The valve body 10 is formed in a cylindrical shape using a metal material such as stainless steel or a resin material. The valve body 10 is provided with a valve seat portion 10a that is erected in an annular shape toward the other side in the axial direction L. A valve port 10b is opened in the center of the valve seat portion 10a, and the other end has an annular valve seat sealing surface 10aa, and a valve chamber 12 is formed on the inside.

[0024] A first connecting pipe 1, which serves as a fluid passage, is connected to one side of the outer circumference of the valve body 10, and this first connecting pipe 1 is in communication with the valve chamber 12. A second connecting pipe 2 is connected to the bottom side of the valve body 10, and this second connecting pipe 2 is in communication with the valve chamber 12 via the valve port 10b. The first connecting pipe 1 and the second connecting pipe 2 are made of materials such as copper or stainless steel, and are fixed to the valve body 10.

[0025] The support member 20 comprises a substantially cylindrical holder portion 21 made of a resin-based material such as polyphenylene sulfide (PPS), and a stainless steel fixing portion 22 integrally provided at the end of the holder portion 21 closer to the valve body 10 by insert molding. The support member 20 is welded and fixed to the valve body 10 by the fixing portion 22.

[0026] The holder portion 21 is positioned such that its axis coincides with the axis L passing through the axis of the valve port 10b. At the center of the holder portion 21, a screw hole 23, a bearing hole 24, and a slide hole 25 are formed concentrically, aligned in the direction of axis L and penetrating the holder portion 21. A female screw portion 23a is formed on the inner circumferential surface of the screw hole 23, into which the male screw portion 31a of the drive shaft 30 (described later) is screwed. The guide portion 32 of the drive shaft 30 (described later) is slidably engaged with the inner circumferential surface of the bearing hole 24. The slide hole 25 is positioned closer to the valve port 10b and is formed with a larger diameter than the bearing hole 24. The valve body portion 40 (described later) is slidably engaged with the slide hole 25.

[0027] A guide rail 26, consisting of spiral ridges, is integrally formed on the outer circumferential surface of the holder portion 21. The guide rail 26 has adjacent winding portions spaced apart from each other. The guide rail 26 is positioned so that its axis coincides with the axis L, and the coil portion 51 of the coil member 50 (described later) is screwed into it, guiding each winding portion of the coil portion 51 from one or both sides so that the coil member 50 can rotate in the circumferential direction.

[0028] The drive shaft 30 is formed in the shape of a cylindrical rod, for example, from a metal such as stainless steel. The drive shaft 30 has a threaded portion 31, a guide portion 32, a constricted portion 33, and a flange portion 34 arranged in order along the axis L. The threaded portion 31 has a male threaded portion 31a, and when this male threaded portion 31a is screwed into the female threaded portion 23a of the holder portion 21, a screw feeding mechanism is formed, and the rotational motion of the drive shaft 30 is converted into linear motion. The guide portion 32 is slidably engaged with the inner circumferential surface of the bearing hole 24, thereby guiding the movement of the drive shaft 30 in the axis L direction. As a result, the drive shaft 30 moves in the axis L direction along with rotation due to the screw feeding action of the screw feeding mechanism. The flange portion 34 rotatably engages with the valve body portion 40, which will be described later. In the first embodiment, the female threaded portion 23a and the male threaded portion 31a are right-hand threads.

[0029] The valve body portion 40 comprises a valve support 41, a valve body 42, an engaging portion 43, a washer 44, a spring receiving portion 45, a compression coil spring 46, and a cover portion 47.

[0030] The valve support 41 is engaged to slide along the slide hole 25 in the axial direction L and has a guide portion 41a and a support portion 41b. The guide portion 41a is formed in a cylindrical shape with an outer diameter substantially the same as the inner diameter of the slide hole 25 of the holder portion 21. The support portion 41b is provided at one end of the guide portion 41a and has a skirt shape that extends radially outward and toward the other end.

[0031] The valve body 42 is made of, for example, a resin material or a metal such as stainless steel, and has a disc-shaped valve body sealing surface 42a provided at one end, a disc-shaped pressure-receiving surface 42b provided at the other end, and a valve body flange portion 42c extending radially outward from the pressure-receiving surface 42b.

[0032] The engaging portion 43 has an L-shaped cross-section and is fitted and fixed to the support portion 41b of the valve support 41. The valve body 42 is loosely fitted and supported between the engaging portion 43 and the support portion 41b of the valve support 41, with a gap in the radial direction and the axial L direction.

[0033] The flange portion 34 of the drive shaft 30 is rotatably hooked to the other end of the valve support 41. Specifically, in the suspended state, a ring-shaped cover portion 47 is fitted and fixed to the other end of the valve support 41 such that a washer 44 is sandwiched between it and the flange portion 34 of the drive shaft 30 (see Figure 3(a)). This cover portion 47 is positioned opposite the constricted portion 33 of the drive shaft 30. This allows the drive shaft 30 to rotate around the axis L of the valve support 41 and move in the direction of the axis L by hooking the valve support 41 via the flange portion 34. The inner diameter of the cover portion 47 is set to be larger than the outer diameter of the constricted portion 33 of the drive shaft 30. In addition, a spring receiving portion 45 is provided within the guide portion 41a of the valve support 41 so as to be movable in the direction of the axis L. A compression coil spring 46 is installed between the spring receiving portion 45 and the support portion 41b of the valve support 41 in a compressed state with a predetermined load applied. As a result, the spring receiving portion 45 is biased toward the other end and comes into contact with one end portion 30a of the drive shaft 30.

[0034] The coil member 50 integrally comprises a coil spring-shaped coil portion 51 and a claw portion 52 projecting radially outward from one end of the coil portion 51. The coil portion 51 is screwed onto the guide rail 26 of the holder portion 21 so as to be circumferentially rotatable. The claw portion 52 can contact the projection 67 of the magnet rotor 62, which will be described later, and the rotation of the magnet rotor 62 pushes the coil member 50 in the circumferential direction via the claw portion 52. As a result, the coil member 50 abuts against an upper limit stopper (not shown) or a lower limit stopper (not shown), restricting the rotation of the coil member 50 and also restricting the rotation of the magnet rotor 62. Therefore, the valve body portion 40 is prevented from moving beyond the position where the valve is at its maximum opening or the position where the valve is closed. This coil member 50 can be easily manufactured by forming a metal wire such as stainless steel.

[0035] The stepping motor 60 comprises a case 61, a magnet rotor 62, and a stator coil (not shown).

[0036] The case 61 is made of a metal such as stainless steel and is formed in a substantially cylindrical shape with its upper end closed. The lower open end of the case 61 is airtightly fixed to the upper end of the valve body 10 by welding or the like.

[0037] The magnet rotor 62 integrally comprises a cylindrical magnet portion 64 with a multi-pole magnetization on its outer circumference and a disc portion 65 that closes one end thereof. The magnet rotor 62 is fixed to the drive shaft 30 via a metal fitting 66 integrally molded in the center of the disc portion 65. As a result, the magnet rotor 62 is rotatably mounted within the case 61 around the axis of the drive shaft 30. The drive shaft 30 is the rotation axis of the magnet rotor 62.

[0038] The stator coil is arranged on the outer surface of the case 61, and when a pulse signal is applied to the stator coil, the magnet rotor 62 rotates according to the number of pulses. The stator coil corresponds to a stepping motor 60.

[0039] When the magnet rotor 62 rotates, the drive shaft 30 rotates together with the magnet rotor 62, and the screw feeding action of the male screw portion 31a and the female screw portion 23a (screw feeding mechanism) causes the drive shaft 30 to move in the axial direction L, causing the valve body portion 40 to move forward and backward relative to the valve seat portion 10a. This controls the flow of fluid from the first joint pipe 1 to the second joint pipe 2 by moving the valve body sealing surface 42a and the valve seat sealing surface 10aa into and out of contact.

[0040] <Regarding conventional problems 1 and 2> As mentioned above, the conventional shut-off valve 1100 shown in Figure 11 employs a screw feed mechanism. Therefore, when the valve body 1142 seats on the valve seat 1110aa, the valve body 1142, which rotates together with the drive shaft 1130, is pressed against the valve seat 1110aa while rotating, resulting in conventional problem 1 (wear due to rotation and pressing on the valve body during seating). Furthermore, the conventional shut-off valve 1100 has assembly errors, so when the valve body 1142 seats on the valve seat 1110aa, the valve body sealing surface and the valve seat sealing surface are not perfectly flush, resulting in conventional problem 2 (reduced sealing performance due to inclination of the valve body sealing surface and valve seat sealing surface).

[0041] Therefore, the conventional shut-off valve 1100 had both conventional problem 1 (wear due to rotation and pressure on the valve body when seated) and conventional problem 2 (reduced sealing performance due to inclination of the valve body sealing surface and valve seat sealing surface), which could lead to a decrease in reliability.

[0042] In contrast, the electric shut-off valve 100a of the first embodiment simultaneously employs a rotation suppression means (1) (the valve body is loosely fitted and supported with respect to the support part) and a pressing force adjustment shut-off means (1) (a state where the valve body is seated under its own weight), thereby simultaneously resolving the conventional problem 1 (wear due to pressing on the valve body and accompanying rotation when seated) and the conventional problem 2 (reduced sealing performance due to the inclination of the valve body sealing surface and the valve seat sealing surface).

[0043] <Details on valve closing operation> From here, the valve closing operation of the electric shut-off valve 100a (suspended state, self-weight seating state, transition state, added seating state, and biased seating state) will be explained in order using Figure 3. During this valve closing operation, rotation suppression means (1), (2) that suppress the transmission of the rotation of the drive shaft 30 to the valve body 42, and pressing force adjustment shut-off means (1) to (3) that adjust the pressing force of the valve body 42 against the valve seat portion 10a and shut off the flow path will be explained while showing them. Note that in Figure 3, since the valve closing operation of the electric shut-off valve 100a is symmetrical, only the left side will be used for explanation. Also, since the valve opening operation is the reverse operation of the valve closing operation, only the valve closing operation will be explained here. Furthermore, when viewed from the direction of axis L, the valve seat sealing surface 10aa is completely covered by the valve body sealing surface 42a.

[0044] <Regarding the suspension setup> The suspended state will be explained using Figure 3(a). In the suspended state, the valve body 40 is integrally connected to the drive shaft 30 by clamping one end of the drive shaft 30 between the washer 44 and the spring receiving portion 45, with the biasing force of the compression coil spring 46 applied. As a result, the valve body 40 moves along the drive shaft 30 in the axial direction L (see arrow M1 in Figure 3(a)) while rotating. Note that the valve body sealing surface 42a of the valve body 42 is separated from the valve seat sealing surface 10aa of the valve seat portion 10a.

[0045] In this configuration, the valve body 42 is placed on the engaging portion 43 via the valve body flange portion 42c, and has a first radial gap tra1 between it and the engaging portion 43, as well as a one-sided axial gap tla1 and a second radial gap tra2 between it and the support portion 41b of the valve support 41. Here, the second radial gap tra2 is set to be larger than the first radial gap tra1 (tra2 > tra1). Furthermore, a gap region Ga is formed between the pressing portion 41ba at the bottom of the support portion 41b and the pressed surface 42b at one end of the valve body 42, so the valve body 42 is suspended from the valve support 41.

[0046] <Regarding the self-weight seating position> The self-weight seating state will be explained using Figure 3(b). In the self-weight seating state, the valve body 40 is integrally connected to the drive shaft 30 by clamping one end of the drive shaft 30, similar to the suspended state. As a result, the valve body 40 moves in the direction of the axis L (see arrow M2 in Figure 3(b)) while rotating together with the drive shaft 30, and the valve body sealing surface 42a of the valve body 42 comes into contact with the valve seat sealing surface 10aa of the valve seat 10a.

[0047] Regarding the rotation suppression means (1) (where the valve body is loosely fitted and supported with respect to the support part): The rotation suppression means (1) (where the valve body is loosely fitted and supported relative to the support portion) is configured such that when the valve body 42 is seated on the valve seat portion 10a, the valve body 42 is in a non-contact state with respect to the support portion 41b and the engagement portion 43 of the valve support 41, and is loosely fitted and supported so as to be movable in the radial direction and the axial direction L.

[0048] Specifically, the valve flange portion 42c of the valve body 42 is separated from the engaging portion 43, and there is still a one-sided axial gap tla1' between the pressing portion 41ba of the support portion 41b and the pressed surface 42b of the valve body 42, forming a gap region Ga. Therefore, when the valve body 42 seats on the valve seat portion 10a, the rotation suppression means (1) (loosely fitting support of the valve body relative to the support portion) causes the valve body 42 to become non-contact with the valve support 41 and the engaging portion 43, and is loosely fitting supported so as to be movable in the radial and axial L directions. In this way, the rotation suppression means (1) (loosely fitting support of the valve body relative to the support portion) acts like a clutch, so that the connection relationship of the valve body 42 with the valve support 41 and the engaging portion 43, that is, the connection relationship with the drive shaft 30 is completely severed, thus eliminating the conventional problem 1 (wear due to pressing and rotation of the valve body when seating).

[0049] Regarding the pressing force adjustment blocking means (1) (self-weight seating state) The pressing force adjustment shutoff means (1) (self-weight seating state) is configured such that when the valve body 42 seats on the valve seat portion 10a, the self-weight of the valve body 42 causes the valve body sealing surface 42a to sit flush with the valve seat sealing surface 10aa, resulting in a self-weight seating state.

[0050] Specifically, in the suspended state of the electric shut-off valve 100a (see Figure 3(a)), due to assembly errors, the valve body sealing surface 42a and the valve seat sealing surface 10aa are not arranged parallel to each other, but are tilted to some extent. In this case, when the valve body 42 is seated on the valve seat portion 10a by the pressing force adjustment shut-off means (1) (self-weight seating state), the valve body sealing surface 42a is seated in accordance with the valve seat sealing surface 10aa due to the weight of the valve body 42, so that they become flush with each other autonomously, thus resolving the conventional problem 2 (reduced sealing performance due to the tilt of the valve body sealing surface and the valve seat sealing surface).

[0051] Based on the above, the electric shut-off valve 100a of the first embodiment can simultaneously eliminate conventional problems 1 (wear due to pressure on the valve body and accompanying rotation when seated) and conventional problems 2 (reduced sealing performance due to inclination of the valve body sealing surface and valve seat sealing surface) by employing a rotation suppression means (1) (valve body loosely fitted and supported with the support part) and a pressing force adjustment shut-off means (1) (self-weight seated state), thereby improving reliability.

[0052] <About transition states> The transition state will be explained using Figure 3(c). The transition state represents the instantaneous state in which the pressing portion 41ba of the support portion 41b comes into contact with the pressed surface 42b of the valve body 42 as the valve body 40 rotates together with the drive shaft 30 in the axial direction L (see arrow M3 in Figure 3(c)). Therefore, in the transition state, the valve body 40 is integrally connected to the drive shaft 30 by clamping one end of the drive shaft 30, similar to the self-weight seating state. Consequently, the valve body 42 is not loosely supported, but is clamped in the axial direction L by the valve support 41 and the valve seat portion 10a. At this time, since the valve support 41 is supported by the drive shaft 30, the self-weight of the valve support 41 is not loaded onto the valve body sealing surface 42a. Therefore, in the transition state, similar to the self-weight seating state (see Figure 3(b)), the valve body sealing surface 42a is pressed against the valve seat sealing surface 10aa by the weight of the valve body 42.

[0053] Since the transition state is an instantaneous state while the drive shaft 30 is moving in the direction of its axis L (see arrow M3 in Figure 3(c)), we will omit considering the rotation suppression means and the pressing force adjustment shutoff means.

[0054] <Regarding the added weight seating state and the biased seating state> The added weight seating state and the biased seating state will be explained using Figure 3(d). Here, the added weight seating state and the biased seating state occur simultaneously. First, the drive shaft 30 moves in the axial direction L (see arrow M4 in Figure 3(d)) while rotating, while the valve support 41 cannot move in the axial direction L together with the drive shaft 30 because it is in contact with the valve seat portion 10a via the valve body 42. Therefore, the drive shaft 30 presses against the spring support portion 45 against the biasing force of the compression coil spring 46 and moves in the axial direction L (see arrow M4 in Figure 3(d)) while rotating. As a result, the clamping of one end of the drive shaft 30 by the valve body portion 40 is released. Furthermore, the valve sealing surface 42a of the valve body 42 is pressed against the valve seat sealing surface 10aa of the valve seat portion 10a by the weight of the valve body 42 and the weight of the valve support 41, resulting in an additional weight seating state, and is also pressed against by the biasing force of the compression coil spring 46, resulting in a biased seating state.

[0055] Regarding the rotation suppression means (2) (where the drive shaft is not clamped to the valve body): The rotation suppression means (2) (where the drive shaft is not clamped by the valve body) has a configuration in which one end of the drive shaft 30 is not clamped by the valve body 40 in the direction of the axis L.

[0056] Specifically, when the drive shaft 30 presses against the spring receiving portion 45 against the biasing force of the compression coil spring 46 and moves in the axial direction L (see arrow M4 in Figure 3(d)) while rotating, the clamping of one end of the drive shaft 30 by the valve body portion 40 is released like a clutch. Due to this rotation suppression means (2) (the drive shaft is not clamped by the valve body portion), the transmission path of rotational force from the drive shaft 30 to the valve body 42 must go through the spring receiving portion 45, the compression coil spring 46, and the support portion 41b, so sliding friction occurs due to the relative rotation between each member. As a result, the rotational force from the drive shaft 30 to the valve body 42 is effectively dissipated.

[0057] As a result, in the first embodiment of the electric shut-off valve 100a, by employing rotation suppression means (2) (the drive shaft is not clamped to the valve body) in addition to rotation suppression means (1) (the valve body is loosely fitted and supported to the support), the transmission of the rotation of the drive shaft 30 to the valve body 42 can be suppressed more reliably.

[0058] Regarding the pressing force adjustment and blocking means (2) (additional self-weight seating state) and the pressing force adjustment and blocking means (3) (biased seating state) The pressing force adjustment shutoff means (2) (additional self-weight seating state) has a configuration in which the valve support 41 is loosely fitted and supported, and the weight of the valve body 42 and the valve support 41 causes the valve body sealing surface 42a to sit flush with the valve seat sealing surface 10aa, resulting in an additional self-weight seating state. The pressing force adjustment shutoff means (3) (biased seating state) has a configuration in which, when the valve body sealing surface 42a is seated flush with the valve seat sealing surface 10aa, the biasing force of the compression coil spring 46 causes the valve body sealing surface 42a to be pressed against the valve seat sealing surface 10aa, resulting in a biased seating state.

[0059] Specifically, the electric shut-off valve 100a transitions from a self-weight seating state (see Figure 3(b)) to an added self-weight seating state and a biased seating state (see Figure 3(d)) via an instantaneously occurring transition state (see Figure 3(c)). Here, in the self-weight seating state (see Figure 3(b)), the valve body sealing surface 42a is pressed against the valve seat sealing surface 10aa in a completely stationary state by the weight of the valve body 42. Subsequently, when transitioning to the added self-weight seating state and the biased seating state (see Figure 3(d)), the clamping of one end of the drive shaft 30 by the valve body 40 is released like a clutch. In this case, the weight of the valve body 42 and valve support 41 acts so that the valve body sealing surface 42a is pressed against the valve seat sealing surface 10aa by the pressing force adjustment shutoff means (2) (additional self-weight seating state), and the biasing force of the compression coil spring 46 acts so that the valve body sealing surface 42a is pressed against the valve seat sealing surface 10aa by the pressing force adjustment shutoff means (3) (biased seating state).

[0060] As a result, in the first embodiment of the electric shut-off valve 100a, by employing a pressing force adjustment shut-off means (2) (additional self-weight seating state) and a pressing force adjustment shut-off means (3) (biased seating state) in addition to the pressing force adjustment shut-off means (1) (self-weight seating state), the pressing force of the valve body 42 against the valve seat portion 10a can be adjusted, thereby more reliably shutting off the flow path.

[0061] <Considerations based on maximum static friction> In the first embodiment of the electric shut-off valve 100a, in the self-weight seating state (see Figure 3(b)), the valve body 42 is completely stationary relative to the valve seat portion 10a. Here, in order for the valve body 42 to still be completely stationary relative to the valve seat portion 10a in the added self-weight seating state and the biased seating state (see Figure 3(d)), the rotational force applied by the drive shaft 30 to the valve body 42 must be less than or equal to the maximum static friction force of the valve body 42 relative to the valve seat portion 10a (fmax = μN: static friction coefficient μ, normal force N).

[0062] In particular, from the moment the valve body 42 enters the biased seating state shown in Figure 3(d), the biasing force (normal force N) of the compression coil spring 46 sandwiched between the spring receiving portion 45 and the support portion 41b is applied to the valve body 42 by the pressing force adjustment blocking means (3) (biased seating state). Furthermore, as the drive shaft 30 rotates and moves in the axial direction L (see arrow M4 in Figure 3(d)), the biasing force (normal force N) of the compression coil spring 46 on the valve body 42 increases rapidly, resulting in a relatively large maximum static friction force (fmax = μN). As a result, even if the valve body 42 or the valve seat portion 10a is made of a highly sliding resin material with a relatively small static friction coefficient μ, the valve body 42 can maintain a completely stationary state relative to the valve seat portion 10a in the added weight seating state and the biased seating state (see Figure 3(d)).

[0063] As a result, in the first embodiment, either the valve body 42 (i.e., the valve body sealing surface 42a) or the valve seat portion 10a (i.e., the valve seat sealing surface 10aa) can be made of a resin material, and the other can be made of a metal material. Furthermore, the resin material in the first embodiment may be, for example, polytetrafluoroethylene (PTFE), perfluoroalkoxyalkane (PFA), nylon, acetal, polyimide (PI), polyester, etc., taking into consideration high sliding properties. In addition, the resin material in the first embodiment may be, for example, polytetrafluoroethylene (PTFE), perfluoroalkoxyalkane (PFA), etc., or polyphenylene sulfide (PPS), polyetheretherketone (PEEK), polyamide (PA), nylon, etc., with additives (graphite, molybdenum, carbon fiber, etc.) added, taking into consideration wear resistance and processability.

[0064] <Regarding the unilateral axial gap that absorbs the tilt of the valve support> From here, using Figure 4, the details of the one-sided axial gap tla1 that absorbs the inclination of the valve body 40 in the electric shut-off valve 100a of the first embodiment will be explained. In Figure 4, the case in which the valve body 40 is inclined with respect to the axis L is explained as an example, but the same explanation can be given even if the drive shaft 30 is inclined, or if both the valve support 41 and the drive shaft 30 are inclined.

[0065] First, Figure 4(a) shows the moment when the drive shaft 30 rotates and moves in the direction of axis L (see arrow M1 in Figure 4(a)), causing it to move from a suspended state to a partially seated state. Here, the valve body 40 has an inclination θ1 with respect to axis L. The valve body 42 is mounted on the engagement portion 43 via the valve body flange portion 42c, and has a unilateral axial gap tla1 between it and the support portion 41b of the valve support 41, forming a gap region Ga.

[0066] Here, as shown in Figure 4(a), if we let L1 be the guide length formed by the guide portion 41a and slide hole 25 of the valve support 41, and a be the radial clearance between the guide portion 41a and slide hole 25 of the valve support 41, and calculate the inclination θ1 of the valve body 40, we get the following equation (Equation 1). tanθ1 = a / L1 (Equation 1)

[0067] Furthermore, if we consider the inner diameter D1 at the seating position of the valve seat sealing surface 10aa and the axial opening gap T1 between the valve seat sealing surface 10aa and the valve body 42, and calculate the inclination θ1 of the valve body sealing surface 42a relative to the valve seat sealing surface 10aa, we obtain the following (Equation 2). tanθ1 = T1 / D1 (Equation 2)

[0068] Furthermore, in Figure 4(a), by setting the axial gap tla1 between the support portion 41b and the valve body 42 to be larger than the axial opening gap T1 between the valve seat sealing surface 10aa and the valve body 42, as shown in (Equation 3) below, it is possible to reliably generate rotational movement in the loose-fit support (see M2m in Figure 4(b)) until the valve body 42 seats on the valve seat portion 10a. tla1 > T1 (Equation 3)

[0069] Substituting (Equation 1) and (Equation 2) into (Equation 3), we can rearrange it to the following (Equation 4). tla1>a×D1 / L1 (Formula 4)

[0070] Therefore, in the electric shut-off valve 100a of the first embodiment, in order to absorb the inclination θ1 of the valve body 40, the rotational movement of the valve body 42 (see M2m in Figure 4(b)) can be reliably generated by setting the axial gap tla1 on one side such that the relational equation (Equation 4) is satisfied. Although there is no upper limit set for the axial gap tla1 on one side, if it becomes too large, the responsiveness of the valve closing and opening operations will be significantly reduced, so it is preferable to set it such that, for example, 0.05 mm ≤ tla1 ≤ 0.4 mm is satisfied.

[0071] Next, as shown in Figure 4(b), the drive shaft 30 rotates and moves in the axial direction L (see arrow M2 in Figure 4(b)), causing the valve flange portion 42c of the valve body 42 to separate from the valve support 41 and the engagement portion 43 in the axial direction L. At this time, as mentioned above, since the axial gap tla1 on one side is set to be larger than the axial opening gap T1 (see Figure 4(a) and Equation 3), the valve body 42 is loosely fitted and supported relative to the valve support 41 and the engagement portion 43 so as to be movable in the radial and axial directions L (see non-contact portion Nc in Figure 4(b)), and a gap region Ga is formed. This ensures that the rotational movement in the loose fitting support (see M2m in Figure 4(b)) occurs reliably until the valve body 42 seats on the valve seat portion 10a due to its own weight.

[0072] As shown in Figure 3(a), the valve body 42 has a first radial gap tra1 between it and the engaging portion 43, and a second radial gap tra2 between it and the support portion 41b of the valve support 41. By setting the second radial gap tra2 to be larger than the first radial gap tra1 (tra2 > tra1), the rotational movement in the loose-fit support (see M2m in Figure 4(b)) can be made even more reliable until the valve body 42 seats on the valve seat portion 10a.

[0073] <Regarding the unilateral axial clearance that absorbs axial screw play> From here, using Figure 3(a), the details of the one-sided axial gap tla1 that absorbs the screw play C (not shown) in the axial L direction in the electric shut-off valve 100a of the first embodiment will be explained. Here, the case in which the screw feeding mechanism formed by the male screw portion 31a and female screw portion 23a (see Figure 1) of the drive shaft 30 has screw play C in the axial L direction will be explained as an example, but a similar explanation can be given even if the drive shaft 30 is misaligned from the desired mounting position in the axial L direction due to assembly errors.

[0074] <Regarding concerns (discrepancies in valve opening and closing operation)> As the drive shaft 30 moves in the axial direction L, the valve body 40 moves forward and backward relative to the valve seat 10a, performing valve opening and closing operations. However, if the axial screw play C of the drive shaft 30 is relatively large, there was a concern that the valve closing operation would occur earlier than the desired valve closing timing, and the valve opening operation would occur later than the desired valve opening timing (hereinafter referred to as "concern (deviation in valve opening and closing operation)").

[0075] In contrast, as shown in Figure 3(a), when the valve body 42 is suspended from the support portion 41b of the valve support 41, the axial gap tla1 on one side between the support portion 41b and the valve body 42 is set to be larger than the screw play C in the axial L direction of the screw feed mechanism (tla1 > C). This makes it possible to determine the timing of the valve opening and closing operation by the axial gap tla1 on one side, without depending on the screw play C in the axial L direction, thus eliminating the concern (deviation in valve opening and closing operation).

[0076] (Valve body modification) Here, we will describe valve body modifications 1 to 4 of the first embodiment using Figure 5. First, valve body modifications 1 and 2 differ from the first embodiment in that they are provided with protrusions 42Aa and 42Ba extending along the axis L on the valve body sealing surface 42a, but the other basic configurations are the same as those of the first embodiment. Also, valve body modifications 3 and 4 differ from the first embodiment in that they are provided with recesses 42Ca and 42Da extending along the axis L on the valve body sealing surface 42a, but the other basic configurations are the same as those of the first embodiment.

[0077] <Regarding concerns (vibration of the valve body due to turbulence occurring when the valve is open)> As shown in Figure 3(a), in the open valve state, the valve body 42 is suspended from the support portion 41b of the valve support 41. At this time, fluid flows from the radially outer to the inner side of the valve body sealing surface 42a of the valve body 42, and the fluids collide violently in the central portion along the axis L. As a result, turbulence is generated near the valve body 42, raising concerns that the valve body 42 may vibrate relative to the support portion 41b (hereinafter referred to as "concern (vibration of the valve body due to turbulence in the open valve state)").

[0078] In contrast, in the valve body modifications 1 to 4 of the first embodiment, the valve body sealing surface 42a of the valve bodies 42A to 42D is provided with flow straightening means consisting of protrusions 42Aa, 42Ba or recesses 42Ca, 42D that extend along the axis L.

[0079] (Variation examples 1 to 4 of this valve) Using Figures 5(a) to 5(d), the valve bodies 42A to 42D in the first embodiment of the valve body modification 1 to 4 will be described. First, in valve body modification 1, a flow straightening means consisting of a frustoconical projection 42Aa extending along the axis L is provided on the valve body sealing surface 42a of valve body 42A. Next, in valve body modification 2, a flow straightening means consisting of a cylindrical projection 42Ba extending along the axis L is provided on the valve body sealing surface 42a of valve body 42B. Furthermore, in valve body modification 3, a flow straightening means consisting of a conical recess 42Ca extending along the axis L is provided on the valve body sealing surface 42a of valve body 42C. In addition, in valve body modification 4, a flow straightening means consisting of a cylindrical recess 42Da extending along the axis L is provided on the valve body sealing surface 42a of valve body 42D.

[0080] As described above, in the modified valve body variations 1 to 4 of the first embodiment, the valve bodies 42A to 42D are provided with projections 42Aa, 42Ba and recesses 42Ca, 42D extending along the axis L as flow straightening means. With this flow straightening means, the fluid flow from the radially outer to the inner side at each valve body sealing surface 42a is smoothly deflected to flow to one side in the direction of the axis L, thereby eliminating concerns (vibration of the valve body due to turbulence that occurs when the valve is open).

[0081] As described above, in the first embodiment of the electric shut-off valve 100a, by simultaneously employing rotation suppression means (1) (valve body loosely fitted and supported with respect to the support part) and pressing force adjustment shut-off means (1) (self-weight seating state), conventional problems 1 (wear due to pressing on the valve body and accompanying rotation when seating) and conventional problems 2 (reduced sealing performance due to inclination of the valve body sealing surface and valve seat sealing surface) can be simultaneously resolved, and reliability can be improved. Furthermore, in the first embodiment of the electric shut-off valve 100a, by employing pressing force adjustment shut-off means (2) (additional self-weight seating state) and pressing force adjustment shut-off means (3) (biased seating state), the pressing force of the valve body 42 on the valve seat part 10a can be adjusted, and the flow path can be shut off more reliably. Moreover, in the first embodiment of the electric shut-off valve 100a, by employing rotation suppression means (2) (drive shaft not clamped to the valve body part), the transmission of rotation of the drive shaft 30 to the valve body 42 can be more reliably suppressed. In addition, in the first embodiment of the electric shut-off valve 100a, the one-sided axial gap tla1 between the support portion 41b and the valve body 42 can be set to be larger than the screw play C in the axial L direction of the screw feed mechanism (tla1 > C), thereby eliminating the concern (deviation in valve opening and closing operation). Furthermore, in the first embodiment of the electric shut-off valve 100a, the maximum static friction force can be made relatively large by the pressing force adjustment shut-off means (3) (biased seating state), so it is possible to adopt a design in which either the valve body sealing surface 42a or the valve seat sealing surface 10aa is made of a resin material and the other is made of a metal material.

[0082] In the first embodiment, all of the rotation suppression means (1) and (2), and the pressing force adjustment and blocking means (1) to (3) are employed, but the embodiment is not limited to this. For example, as long as at least the rotation suppression means (1) and the pressing force adjustment and blocking means (1) are employed simultaneously, the embodiment may not employ any of the rotation suppression means (2) or the pressing force adjustment and blocking means (2) and (3), or it may employ a combination that includes at least one of them.

[0083] Furthermore, in the modified valve body 1 to 4 of the electric shut-off valve 100a of the first embodiment, the issue of rectification means is employed in the valve bodies 42A to 42D, thereby eliminating the concern (vibration of the valve body due to turbulence that occurs when the valve is open).

[0084] (Second embodiment) The electric shut-off valve 100b according to the second embodiment will be described with reference to Figures 6 to 8. The electric shut-off valve 100b according to the second embodiment differs from the electric shut-off valve 100a of the first embodiment in that an overhang portion 45a' is provided on the spring receiving portion 45', but the other basic configurations are the same as those of the first embodiment. Here, the same reference numerals are used for the same components, and redundant explanations are omitted.

[0085] <Regarding the configuration of the electric shut-off valve> An electric shut-off valve 100b according to a second embodiment of the present invention will be described with reference to Figure 6. The electric shut-off valve 100b mainly consists of a valve body 10, a support member 20 (see Figure 1), a drive shaft 30, a valve body 40', a coil member 50 (see Figure 1), and a stepping motor 60 (see Figure 1). Below, the spring receiving portion 45' of the valve body 40', which differs from the electric shut-off valve 100a of the first embodiment, will be described.

[0086] <Regarding the spring support section> The spring receiving portion 45' further includes an annular protruding portion 45a' on its other end. This protruding portion 45a' abuts against the washer 44. As will be described in detail later, the axial length of the protruding portion 45a' is set to be greater than the axial length from one end 30a of the drive shaft 30 to the other end of the flange portion 34. Therefore, as a rotation suppression means (2'), when the valve body 42 is seated on the valve seat portion 10a, the valve support 41 is loosely fitted and supported so as to be movable in the radial and axial directions relative to one end 30a of the drive shaft 30.

[0087] <Details on valve closing operation> From here, the valve closing operation of the electric shut-off valve 100b (suspended state, self-weight seating state, transition state, added seating state, biased seating state) will be explained in order using Figure 7. The rotation suppression means (1), (2') that suppress the transmission of the rotation of the drive shaft 30 to the valve body 42 during this valve closing operation, and the pressing force adjustment shut-off means (1) to (3) that adjust the pressing force of the valve body 42 against the valve seat portion 10a and shut off the flow path will be explained while showing them. In the second embodiment, rotation suppression means (2') is used instead of rotation suppression means (2) in the first embodiment.

[0088] <Regarding the suspension setup> The suspended state will be explained using Figure 7(a). In the suspended state, the valve body 40' is supported by a washer 44 sandwiched between the spring receiving portion 45' and the cover portion 47, with the biasing force of the compression coil spring 46 applied to it, while being loosely fitted and supported on one end 30a of the drive shaft 30 so as to be movable in the radial and axial L directions. As a result, the valve body 40' moves along the drive shaft 30 while rotating in the axial L direction (see arrow M1' in Figure 7(a)). Note that the valve body sealing surface 42a of the valve body 42 is separated from the valve seat sealing surface 10aa of the valve seat portion 10a.

[0089] In this configuration, the valve body 42 is mounted on the engagement portion 43 via the valve body flange portion 42c, and has a first radial gap trb1 between it and the engagement portion 43, as well as a one-sided axial gap tlb1 and a second radial gap trb2 between it and the support portion 41b of the valve support 41. Furthermore, there is an other-sided axial gap tlb2 between the spring receiving portion 45' and one end portion 30a of the drive shaft 30. Here, the one-sided axial gap tlb1 is set to be larger than the other-sided axial gap tlb2 (tlb1 > tlb2). The second radial gap trb2 is set to be larger than the first radial gap trb1, similar to the first embodiment (trb2 > trb1).

[0090] <Regarding the self-weight seating position> The self-weight seating state will be explained using Figure 7(b). In the self-weight seating state, the valve body 40' is loosely fitted and supported on one end 30a of the drive shaft 30 so as to be movable in the radial and axial L directions, similar to the suspended state. As a result, the valve body 40' moves along the drive shaft 30 while rotating in the axial L direction (see arrow M2' in Figure 7(b)), and the valve body sealing surface 42a of the valve body 42 comes into contact with the valve seat sealing surface 10aa of the valve seat 10a. At this time, there is still a one-sided axial gap tlb1' between the pressing portion 41ba of the support portion 41b and the pressed surface 42b of the valve body 42, and a gap region Ga is formed.

[0091] Regarding the rotation suppression means (1) (where the valve body is loosely fitted and supported with respect to the support part): The rotation suppression means (1) (loosely fitted support of the valve body relative to the support portion) is configured, similar to the first embodiment, such that when the valve body 42 seats on the valve seat portion 10a, the valve body 42 is in a non-contact state with respect to the support portion 41b of the valve support 41 and is loosely fitted and supported so as to be movable in the radial direction and the axial direction L. By adopting this rotation suppression means (1) (loosely fitted support of the valve body relative to the support portion), the conventional problem 1 (wear due to pressure on the valve body and accompanying rotation when seating) can be eliminated.

[0092] Regarding the rotation suppression means (2') (where the valve body is loosely fitted and supported relative to the drive shaft): The rotation suppression means (2') (where the valve body is loosely fitted and supported with respect to the drive shaft) has a configuration in which the valve body 40' is loosely fitted and supported with respect to one end 30a of the drive shaft 30 so as to be movable in the radial direction and the axial direction L.

[0093] As a result, in the electric shut-off valve 100b of the second embodiment, in addition to rotation suppression means (1) (valve body is loosely fitted and supported with respect to the support portion), rotation suppression means (2') (valve body portion is loosely fitted and supported with respect to the drive shaft) can be employed to more reliably suppress the transmission of rotation of the drive shaft 30 to the valve body 42.

[0094] Regarding the pressing force adjustment blocking means (1) (self-weight seating state) The pressing force adjustment shutoff means (1) (self-weight seating state) is configured, similar to the first embodiment, to be in a self-weight seating state in which, when the valve body 42 seats on the valve seat portion 10a, the valve body sealing surface 42a seats flush with the valve seat sealing surface 10aa due to the weight of the valve body 42. By adopting this pressing force adjustment shutoff means (1) (self-weight seating state), the conventional problem 2 (reduced sealing performance due to inclination of the valve body sealing surface and the valve seat sealing surface) can be resolved.

[0095] Based on the above, in the second embodiment of the electric shut-off valve 100b, similar to the first embodiment, by simultaneously employing rotation suppression means (1) (valve body loosely fitted and supported with respect to the support part) and pressing force adjustment shut-off means (1) (self-weight seating state), conventional problems 1 (wear due to pressing and accompanying rotation of the valve body when seating) and conventional problems 2 (reduced sealing performance due to inclination of the valve body sealing surface and valve seat sealing surface) can be simultaneously resolved, and reliability can be improved. Furthermore, in the second embodiment of the electric shut-off valve 100b, by employing rotation suppression means (2') (valve body loosely fitted and supported with respect to the drive shaft), the transmission of rotation of the drive shaft 30 to the valve body 42 can be suppressed more reliably.

[0096] <Regarding the added weight and seating position> The state of seating under added weight will be explained using Figure 7(c). First, as the valve body 40' rotates together with the drive shaft 30 and moves in the axial direction L (see arrow M3' in Figure 7(c)), the pressing portion 41ba of the support portion 41b comes into contact with the pressed surface 42b of the valve body 42. Then, as the drive shaft 30 rotates further and moves in the axial direction L (see arrow M3' in Figure 7(c)), the drive shaft 30 becomes non-contact with the valve body 40'. At this time, there is a gap tlb2' in the other axial direction between the spring receiving portion 45' and one end 30a of the drive shaft 30. As a result, the valve body sealing surface 42a of the valve body 42 is pressed against the valve seat sealing surface 10aa of the valve seat portion 10a by the weight of the valve body 42 in addition to the weight of the valve support 41, resulting in a state of seating under added weight.

[0097] Regarding the rotation suppression means (2') (where the valve body is loosely fitted and supported relative to the drive shaft): The rotation suppression means (2') (where the valve body is loosely fitted and supported relative to the drive shaft) has a configuration in which, similar to the self-weight seating state, the valve body 40' is in a non-contact state with respect to one end 30a of the drive shaft 30 and is loosely fitted and supported so as to be movable in the radial direction and the axial direction L.

[0098] As a result, in the electric shut-off valve 100b of the second embodiment, in addition to rotation suppression means (1) (valve body is loosely fitted and supported with respect to the support portion), rotation suppression means (2') (valve body portion is loosely fitted and supported with respect to the drive shaft) can be employed to more reliably suppress the transmission of rotation of the drive shaft 30 to the valve body 42.

[0099] Regarding the pressing force adjustment blocking means (2) (additional self-weight seating state): The pressing force adjustment blocking means (2) (additional self-weight seating state) is configured, similar to the first embodiment, in which the valve support 41 is loosely fitted and supported, and the weight of the valve body 42 and the valve support 41 causes the valve body sealing surface 42a to sit flush with the valve seat sealing surface 10aa, resulting in an additional self-weight seating state.

[0100] As a result, in the electric shut-off valve 100b of the second embodiment, by employing a pressing force adjustment shut-off means (2) (additional self-weight seating state) in addition to the pressing force adjustment shut-off means (1) (self-weight seating state), the pressing force of the valve body 42 against the valve seat portion 10a can be adjusted, thereby more reliably shutting off the flow path.

[0101] <Regarding the biased seating position> The biased seating state will be explained using Figure 7(d). Here, the drive shaft 30 rotates and moves in the axial direction L (see arrow M4' in Figure 7(d)), coming into contact with the spring receiving portion 45' and pressing against the spring receiving portion 45' against the biasing force of the compression coil spring 46. As a result, the valve body sealing surface 42a of the valve body 42 is pressed against the valve seat sealing surface 10aa of the valve seat portion 10a by the biasing force of the compression coil spring 46, resulting in a biased seating state.

[0102] Regarding the rotation suppression means (2') (where the valve body is loosely fitted and supported relative to the drive shaft): The rotation suppression means (2') (where the valve body is loosely fitted and supported relative to the drive shaft) has a configuration in which the valve body 40' is loosely fitted and supported relative to one end 30a of the drive shaft 30 so as to be movable in the radial direction and the axial direction L, similar to the self-weight seating state.

[0103] As a result, in the electric shut-off valve 100b of the second embodiment, in addition to rotation suppression means (1) (valve body is loosely fitted and supported with respect to the support portion), rotation suppression means (2') (valve body portion is loosely fitted and supported with respect to the drive shaft) can be employed to more reliably suppress the transmission of rotation of the drive shaft 30 to the valve body 42.

[0104] Regarding the pressing force adjustment and blocking means (2) (additional self-weight seating state) and the pressing force adjustment and blocking means (3) (biased seating state) The pressing force adjustment shutoff means (2) (additional self-weight seating state) is configured, similar to the first embodiment, in which the valve support 41 is loosely fitted and supported, and the weight of the valve body 42 and the valve support 41 causes the valve body sealing surface 42a to sit flush with the valve seat sealing surface 10aa, resulting in an additional self-weight seating state. The pressing force adjustment shutoff means (3) (biased seating state) is configured, similar to the first embodiment, in which, when the valve body sealing surface 42a is seated flush with the valve seat sealing surface 10aa, the biasing force of the compression coil spring 46 causes the valve body sealing surface 42a to be pressed against the valve seat sealing surface 10aa, resulting in a biased seating state.

[0105] As a result, in the electric shut-off valve 100b of the second embodiment, by employing a pressing force adjustment shut-off means (2) (additional self-weight seating state) and a pressing force adjustment shut-off means (3) (biased seating state) in addition to the pressing force adjustment shut-off means (1) (self-weight seating state), the pressing force of the valve body 42 against the valve seat portion 10a can be adjusted, thereby more reliably shutting off the flow path.

[0106] In the second embodiment, as in the first embodiment, the maximum static friction force can be made relatively large by the pressing force adjustment blocking means (3) (biased seating state). Therefore, it is possible to adopt a configuration in which either the valve body 42 (i.e., the valve body sealing surface 42a) or the valve seat portion 10a (i.e., the valve seat sealing surface 10aa) is made of a resin material and the other is made of a metal material. Furthermore, the resin material in the second embodiment may be, as in the first embodiment, polytetrafluoroethylene (PTFE), perfluoroalkoxyalkane (PFA), nylon, acetal, polyimide (PI), polyester, etc., taking into consideration high sliding properties. Furthermore, the resin material in the second embodiment may be polytetrafluoroethylene (PTFE), perfluoroalkoxyalkane (PFA), or polyphenylene sulfide (PPS), polyetheretherketone (PEEK), polyamide (PA), nylon, etc., with additives (graphite, molybdenum, carbon fiber, etc.) added, taking into consideration abrasion resistance and processability, similar to the first embodiment.

[0107] <Regarding the axial gap on the other side that absorbs the tilt of the valve support> From here, using Figure 8, the details of the other-side axial gap tlb2 that absorbs the inclination of the valve body 40' in the electric shut-off valve 100b of the second embodiment will be explained. In Figure 8, the case in which the valve body 40' is inclined with respect to the axis L is explained as an example, but the same explanation can be given even if the drive shaft 30 is inclined, or if both the valve support 41 and the drive shaft 30 are inclined.

[0108] Here, the electric shut-off valve 100b of the second embodiment has a one-sided axial gap tlb1 and a other-sided axial gap tlb2, as shown in Figure 7(a). Between the self-weight seating state and the added self-weight seating state, the tilt of the valve support 41' is first absorbed by the one-sided axial gap tlb1, and then further absorbed by the other-sided axial gap tlb2. However, the explanation of how the one-sided axial gap tlb1 absorbs the tilt of the valve support 41' is redundant with the previously mentioned <Regarding the one-sided axial gap that absorbs the tilt of the valve support>, so it will be omitted here, and the explanation will focus on how the other-sided axial gap tlb2 absorbs the tilt of the valve support 41'. Therefore, Figure 8(a) corresponds to Figure 4(b).

[0109] First, Figure 8(a) shows the self-weight seating state in which the valve body 42 is seated on the valve seat portion 10a due to its own weight, as the drive shaft 30 rotates and moves in the direction of the axis L (see arrow M2' in Figure 8(a)). Here, the valve body portion 40' has an inclination θ1 with respect to the axis L.

[0110] As shown in Figure 8(a), if we let L1 be the guide length formed by the guide portion 41a and slide hole 25 of the valve support 41, and a be the radial clearance between the guide portion 41a and slide hole 25 of the valve support 41, and calculate the inclination θ1 of the valve body portion 40', we obtain the aforementioned (Equation 1). tanθ1 = a / L1 (Equation 1)

[0111] Furthermore, if we consider the outer diameter D2 at the contact position of the flange portion 34 and the axial gap T2 between the flange portion 34 and the washer 44, and calculate the inclination θ1 of the washer 44 relative to the flange portion 34, we obtain the following equation (Equation 5). tanθ1 = T2 / D2 (Equation 5)

[0112] Furthermore, in Figure 8(a), by setting the other-side axial gap tlb2 between the spring receiving portion 45' and one end 30a of the drive shaft 30 to be larger than the axial gap T2 between the flange portion 34 and the washer 44, as shown in (Equation 6) below, the rotational movement in the loose-fit support (see M3m' in Figure 8(b)) can be reliably generated until the pressing portion 41ba of the valve support 41 contacts the pressed surface 42b of the valve body 42. tlb2>T2 (Formula 6)

[0113] Substituting (Equation 1) and (Equation 5) into (Equation 6), we can rearrange it to the following (Equation 7). tlb2>a×D2 / L1 (Formula 7)

[0114] Therefore, in the electric shut-off valve 100b of the second embodiment, in order to absorb the inclination θ1 of the valve body 40', the other-side axial gap tlb2 is set such that the relational equation (Equation 7) is satisfied, thereby ensuring that the rotational movement of the valve body 40' (see M3m' in Figure 8(b)) occurs reliably. Although there is no upper limit set for the other-side axial gap tlb2, if it becomes too large, the responsiveness of the valve closing and valve opening operations will be significantly reduced, so it is preferable to set it such that, for example, 0.01 mm ≤ tlb2 ≤ 0.1 mm is satisfied.

[0115] Next, as shown in Figure 8(b), the drive shaft 30 rotates and moves in the axial direction L (see arrow M3' in Figure 8(b)), resulting in the drive shaft 30 being in a non-contact state with the valve body 40' (see non-contact portion Nc in Figure 8(b)). At this time, as mentioned above, the other-side axial gap tlb2 is set to be larger than the axial gap T2 (see Figure 8(a) and Equation 6), so the valve body 40' is loosely fitted and supported on the drive shaft 30 so that it can move radially and in the axial direction L (see non-contact portion Nc in Figure 8(b)). This ensures that the rotational movement in the loose fit support (see M3m' in Figure 8(b)) occurs until the pressing portion 41ba of the valve support 41 contacts the pressed surface 42b of the valve body 42 due to the weight of the valve body 40'.

[0116] Furthermore, as shown in Figure 7(a), by setting the second radial gap trb2 to be larger than the first radial gap trb1 (trb2 > trb1), the rotational movement in the loose-fit support (see M3m' in Figure 8(b)) can be made even more reliable until the valve body 42 seats on the valve seat portion 10a.

[0117] Furthermore, in the second embodiment, the axial gap tlb1 on one side, as shown in Figure 7(a), is set to be larger than the axial gap tlb2 on the other side. This makes the time from when the valve body 42 sits on the valve seat portion 10a until it reaches the self-weight seating state relatively longer than the time from when it moves from the added self-weight seating state to when it moves

[0118] As described above, in the second embodiment of the electric shut-off valve 100b, similar to the first embodiment, by simultaneously employing rotation suppression means (1) (valve body loosely fitted and supported with respect to the support part) and pressing force adjustment shut-off means (1) (self-weight seating state), conventional problem 1 (wear due to pressing on the valve body and accompanying rotation when seating) and conventional problem 2 (reduced sealing performance due to inclination of the valve body sealing surface and valve seat sealing surface), reliability can be improved. Furthermore, in the second embodiment of the electric shut-off valve 100b, similar to the first embodiment, by employing pressing force adjustment shut-off means (2) (additional self-weight seating state) and pressing force adjustment shut-off means (3) (biased seating state), the pressing force of the valve body 42 on the valve seat part 10a can be adjusted, and the flow path can be shut off more reliably. Moreover, in the second embodiment of the electric shut-off valve 100b, by employing rotation suppression means (2') (valve body part loosely fitted and supported with respect to the drive shaft), the transmission of rotation of the drive shaft 30 to the valve body 42 can be more reliably suppressed. In addition, in the second embodiment of the electric shut-off valve 100b, similar to the first embodiment, the one-sided axial gap tla1 between the support portion 41b and the valve body 42 is set to be larger than the screw play C in the axial L direction of the screw feed mechanism (tla1 > C), thereby eliminating the concern (deviation in valve opening and closing operation). Furthermore, in the second embodiment of the electric shut-off valve 100b, by setting the one-sided axial gap tlb1 to be larger than the other-sided axial gap tlb2, the time until the valve body is seated under its own weight can be increased. This makes it more reliable for the valve body sealing surface 42a to seat flush with the valve seat sealing surface 10aa due to the weight of the valve body 42, and shortens the time from the added weight seating state to the biased seating state. As a result, the sealing performance between the valve seat sealing surface 10aa and the valve body sealing surface 42a can be improved more quickly. Furthermore, in the electric shut-off valve 100b of the second embodiment, the maximum static friction force can be made relatively large by the pressing force adjustment shut-off means (3) (biased seating state), so it is possible to adopt a configuration in which either the valve body sealing surface 42a or the valve seat sealing surface 10aa is made of a resin material and the other is made of a metal material.

[0119] In the second embodiment, all of the rotation suppression means (1), (2') and the pressing force adjustment and blocking means (1) to (3) are employed, but the embodiment is not limited to this. For example, as long as at least the rotation suppression means (1) and the pressing force adjustment and blocking means (1) are employed simultaneously, the embodiment may not employ any of the rotation suppression means (2') or the pressing force adjustment and blocking means (2), (3), or it may employ a combination that includes at least one of them.

[0120] Furthermore, in the electric shut-off valve 100b of the second embodiment, the concerns (vibration of the valve body due to turbulence occurring in the valve open state) can be eliminated by employing the flow straightening means of the modified valve body 1 to 4, similar to the first embodiment.

[0121] (Third embodiment) The electric shut-off valve 100c according to the third embodiment will be described with reference to Figures 9 to 10. The electric shut-off valve 100c according to the third embodiment differs from the electric shut-off valve 100b of the second embodiment in that the support portion 41b'' of the valve support 41'' has a structure in which the inside of the valve body 42'' is loosely fitted and supported, but the other basic configurations are the same as those of the second embodiment. Here, the same reference numerals are used for the same components, and redundant explanations are omitted.

[0122] <Regarding the configuration of the electric shut-off valve> An electric shut-off valve 100c according to a third embodiment of the present invention will be described with reference to Figure 9. The electric shut-off valve 100c mainly consists of a valve body 10, a support member 20 (see Figure 1), a drive shaft 30, a valve body 40'', a coil member 50 (see Figure 1), and a stepping motor 60 (see Figure 1). Below, the valve support 41'' and valve body 42'' in the valve body 40'', which differ from the electric shut-off valve 100b of the second embodiment, will be described.

[0123] <About the valve support> The valve support 41'' is engaged to slide along the slide hole 25 in the axial direction L and has a guide portion 41a and a support portion 41b'' provided at one end of the guide portion 41a. The guide portion 41a is formed in a cylindrical shape with an outer diameter substantially the same as the inner diameter of the slide hole 25 of the holder portion 21. The support portion 41b'' has a reduced diameter portion 41bc'' which is smaller in diameter than the guide portion 41a, an engaging portion 41bb'' which is provided at one end of the reduced diameter portion 41bc'' and has a disc shape, and a pressing portion 41ba'' provided at the step between the guide portion 41a and the reduced diameter portion 41bc''.

[0124] The valve body 42'' is made of, for example, a resin material or a metal such as stainless steel, and has an upward-facing C-shaped cross-section that defines the housing space As. The valve body 42'' has a disc-shaped valve body sealing surface 42a'' provided at one end, a C-shaped pressure-receiving surface 42b'' provided at the other end, and a lip piece 42c'' provided at the other end that extends radially inward. Here, the valve body 42'' is loosely fitted and supported by having a gap between the housing space As and the support portion 41b'' in the radial and axial L directions.

[0125] <Details on valve closing operation> From here, the valve closing operation of the electric shut-off valve 100c (suspended state, self-weight seating state, transition state, added seating state, biased seating state) will be explained in order using Figure 10. This will be explained while showing the rotation suppression means (1'), (2') that suppress the transmission of the rotation of the drive shaft 30 to the valve body 42'' during this valve closing operation, and the pressure adjustment shut-off means (1') to (3') that adjust the pressing force of the valve body 42'' against the valve seat portion 10a and shut off the flow path. Note that the third embodiment differs from the second embodiment only in the loose fitting support structure between the valve support 41'' and the valve body 42'', so the rotation suppression means (1'), (2') and pressure adjustment shut-off means (1') to (3') are the same as the rotation suppression means (1), (2') and pressure adjustment shut-off means (1) to (3) in the second embodiment.

[0126] <Regarding the suspension setup> The suspension state will be explained using Figure 10(a). Similar to the second embodiment, in the suspension state, the valve body 40'' is loosely fitted and supported so as to be movable radially and axially in the L direction on one end 30a of the drive shaft 30 by sandwiching a washer 44 between the spring receiving portion 45' and the cover portion 47, with the biasing force of the compression coil spring 46 applied. As a result, the valve body 40'' moves along the drive shaft 30 while rotating in the axial direction L (see arrow M1'' in Figure 10(a)). Note that the valve body sealing surface 42a'' of the valve body 42'' is separated from the valve seat sealing surface 10aa of the valve seat portion 10a.

[0127] In this configuration, the valve body 42'' is placed on the engaging portion 41bb'' via the lip piece 42c'', and has a first radial gap trc1 between it and the engaging portion 41bb'', a second radial gap trc2 between it and the reduced diameter portion 41bc'', and a one-sided axial gap tlc1 between it and the pressing portion 41ba'' of the support portion 41b''. Additionally, there is an other-sided axial gap tlc2 between the spring receiving portion 45' and one end 30a of the drive shaft 30. Here, the one-sided axial gap tlc1 is set to be larger than the other-sided axial gap tlb2 (tlc1 > tlc2). Also, the second radial gap trc2 is set to be larger than the first radial gap trc1, similar to the second embodiment (trc2 > trc1). This makes it possible to more reliably generate the rotational movement until the valve body 42'' is fully seated on the valve seat portion 10a in the self-weight seating state.

[0128] <Regarding the self-weight seating position> The self-weight seating state will be explained using Figure 10(b). In the self-weight seating state, the valve body 40'' is loosely fitted and supported on one end 30a of the drive shaft 30 so as to be movable in the radial and axial L directions, similar to the suspended state. As a result, the valve body 40'' moves along the drive shaft 30 while rotating in the axial L direction (see arrow M2'' in Figure 10(b)), and the valve body sealing surface 42a'' of the valve body 42'' comes into contact with the valve seat sealing surface 10aa of the valve seat 10a. At this time, there is still a one-sided axial gap tlc1' between the pressing portion 41ba'' of the support portion 41b'' and the pressed surface 42b'' of the valve body 42''.

[0129] Regarding the rotation suppression means (1') (where the valve body is loosely fitted and supported relative to the support part): The rotation suppression means (1') (loosely fitted support of the valve body relative to the support portion) is configured, similar to the second embodiment, such that when the valve body 42'' seats on the valve seat portion 10a, the valve body 42'' becomes non-contact with the support portion 41b'' of the valve support 41'' and is loosely fitted and supported so as to be movable in the radial and axial L directions. By adopting this rotation suppression means (1') (loosely fitted support of the valve body relative to the support portion), the conventional problem 1 (wear due to pressing on the valve body and accompanying rotation when seating) can be eliminated.

[0130] Regarding the rotation suppression means (2') (where the valve body is loosely fitted and supported relative to the drive shaft): The rotation suppression means (2') (where the valve body is loosely fitted and supported relative to the drive shaft) is configured, similar to the second embodiment, such that the valve body 40'' is loosely fitted and supported relative to one end 30a of the drive shaft 30 so as to be movable in the radial and axial L directions.

[0131] As a result, in the third embodiment of the electric shut-off valve 100c, in addition to the rotation suppression means (1') (where the valve body is loosely fitted and supported by the support portion), a rotation suppression means (2') (where the valve body portion is loosely fitted and supported by the drive shaft) is also employed, similar to the second embodiment, thereby more reliably suppressing the transmission of the rotation of the drive shaft 30 to the valve body 42''.

[0132] Regarding the pressing force adjustment shutoff means (1') (self-weight seating state) The pressing force adjustment shutoff means (1') (self-weight seating state) is configured, similar to the second embodiment, to be in a self-weight seating state in which, when the valve body 42'' seats on the valve seat portion 10a, the valve body sealing surface 42a'' is seated flush with the valve seat sealing surface 10aa due to the weight of the valve body 42''. By adopting this pressing force adjustment shutoff means (1') (self-weight seating state), the conventional problem 2 (reduced sealing performance due to inclination of the valve body sealing surface and the valve seat sealing surface) can be resolved.

[0133] Based on the above, in the third embodiment of the electric shut-off valve 100c, similar to the second embodiment, by simultaneously employing a rotation suppression means (1') (valve body is loosely fitted and supported with respect to the support part) and a pressing force adjustment shut-off means (1') (self-weight seating state), the conventional problem 1 (wear due to pressing and accompanying rotation of the valve body when seating) and the conventional problem 2 (reduced sealing performance due to inclination of the valve body sealing surface and valve seat sealing surface) can be simultaneously resolved, and reliability can be improved. Furthermore, in the third embodiment of the electric shut-off valve 100c, similar to the second embodiment, by employing a rotation suppression means (2') (valve body is loosely fitted and supported with respect to the drive shaft), the transmission of rotation of the drive shaft 30 to the valve body 42'' can be more reliably suppressed.

[0134] <Regarding the added weight and seating position> The state of seating due to added self-weight will be explained using Figure 10(c). First, as the valve body 40'' rotates together with the drive shaft 30 and moves in the axial direction L (see arrow M3'' in Figure 10(c)), the pressing portion 41ba'' of the support portion 41b'' comes into contact with the pressed surface 42b'' of the valve body 42''. Then, as the drive shaft 30 rotates further and moves in the axial direction L (see arrow M3'' in Figure 10(c)), the drive shaft 30 becomes non-contact with the valve body 40''. At this time, there is a gap tlc2'' in the other axial direction between the spring receiving portion 45' and one end 30a of the drive shaft 30. As a result, the valve body sealing surface 42a'' of the valve body 42'' is pressed against the valve seat sealing surface 10aa of the valve seat portion 10a by the weight of the valve support 41'' in addition to the weight of the valve body 42'', resulting in a state of seating due to added self-weight.

[0135] Regarding the rotation suppression means (2') (where the valve body is loosely fitted and supported relative to the drive shaft): The rotation suppression means (2') (where the valve body is loosely fitted and supported relative to the drive shaft) has a configuration similar to the second embodiment, in which the valve body 40'' is loosely fitted and supported relative to one end 30a of the drive shaft 30 in a non-contact state, and is movable in the radial and axial L directions.

[0136] As a result, in the electric shut-off valve 100c of the third embodiment, in addition to the rotation suppression means (1') (where the valve body is loosely fitted and supported with respect to the support portion), a rotation suppression means (2') (where the valve body portion is loosely fitted and supported with respect to the drive shaft) can be employed to more reliably suppress the transmission of the rotation of the drive shaft 30 to the valve body 42''.

[0137] Regarding the pressing force adjustment blocking means (2') (additional self-weight seating state) The pressing force adjustment blocking means (2') (additional self-weight seating state) is configured, similar to the second embodiment, in which the valve support 41'' is loosely fitted and supported, and the weight of the valve body 42'' and the valve support 41'' causes the valve body sealing surface 42a'' to sit flush with the valve seat sealing surface 10aa, resulting in an additional self-weight seating state.

[0138] As a result, in the electric shut-off valve 100b of the third embodiment, by employing a pressing force adjustment shut-off means (2') (additional self-weight seating state) in addition to the pressing force adjustment shut-off means (1') (self-weight seating state), the pressing force of the valve body 42'' against the valve seat portion 10a can be adjusted, thereby more reliably shutting off the flow path.

[0139] <Regarding the biased seating position> The biased seating state will be explained using Figure 10(d). Here, the drive shaft 30 rotates and moves in the axial direction L (see arrow M4'' in Figure 10(d)), coming into contact with the spring receiving portion 45' and pressing against the spring receiving portion 45' against the biasing force of the compression coil spring 46. As a result, the valve body sealing surface 42a'' of the valve body 42'' is pressed against the valve seat sealing surface 10aa of the valve seat portion 10a by the biasing force of the compression coil spring 46, resulting in a biased seating state.

[0140] Regarding the rotation suppression means (2') (where the valve body is loosely fitted and supported relative to the drive shaft): The rotation suppression means (2') (where the valve body is loosely fitted and supported relative to the drive shaft) is configured, similar to the second embodiment, such that the valve body 40'' is loosely fitted and supported relative to one end 30a of the drive shaft 30 so as to be movable in the radial and axial L directions.

[0141] As a result, in the electric shut-off valve 100c of the third embodiment, in addition to the rotation suppression means (1') (where the valve body is loosely fitted and supported with respect to the support portion), a rotation suppression means (2') (where the valve body portion is loosely fitted and supported with respect to the drive shaft) can be employed to more reliably suppress the transmission of the rotation of the drive shaft 30 to the valve body 42''.

[0142] Regarding the pressing force adjustment and blocking means (2') (additional self-weight seating state) and the pressing force adjustment and blocking means (3') (biased seating state) The pressing force adjustment shutoff means (2') (additional self-weight seating state) is configured, similar to the second embodiment, in which the valve support 41'' is loosely fitted and supported, and the weight of the valve body 42'' and valve support 41'' causes the valve body sealing surface 42a'' to sit flush with the valve seat sealing surface 10aa, resulting in an additional self-weight seating state. Furthermore, the pressing force adjustment shutoff means (3') (biased seating state) is configured, similar to the second embodiment, in which, when the valve body sealing surface 42a'' is seated flush with the valve seat sealing surface 10aa, the biasing force of the compression coil spring 46 causes the valve body sealing surface 42a'' to be pressed against the valve seat sealing surface 10aa, resulting in a biased seating state.

[0143] As a result, in the third embodiment of the electric shut-off valve 100c, by employing a pressing force adjustment shut-off means (2') (additional self-weight seating state) and a pressing force adjustment shut-off means (3') (biased seating state) in addition to the pressing force adjustment shut-off means (1') (self-weight seating state), the pressing force of the valve body 42'' against the valve seat portion 10a can be adjusted, thereby more reliably shutting off the flow path.

[0144] In the third embodiment, as in the second embodiment, the maximum static friction force can be made relatively large by the pressing force adjustment blocking means (3') (biased seating state). Therefore, it is possible to adopt a configuration in which either the valve body 42'' (i.e., the valve body sealing surface 42a'') or the valve seat portion 10a (i.e., the valve seat sealing surface 10aa) is made of a resin material and the other is made of a metal material. Furthermore, the resin material in the third embodiment may be, as in the second embodiment, polytetrafluoroethylene (PTFE), perfluoroalkoxyalkane (PFA), nylon, acetal, polyimide (PI), polyester, etc., taking into consideration high sliding properties. Furthermore, the resin material in the second embodiment may be polytetrafluoroethylene (PTFE), perfluoroalkoxyalkane (PFA), or polyphenylene sulfide (PPS), polyetheretherketone (PEEK), polyamide (PA), nylon, etc., with additives (graphite, molybdenum, carbon fiber, etc.) added, taking into consideration abrasion resistance and processability, similar to the first embodiment.

[0145] Based on the above, in the third embodiment of the electric shut-off valve 100c, similar to the second embodiment, by simultaneously employing a rotation suppression means (1') (valve body loosely fitted and supported with respect to the support part) and a pressing force adjustment shut-off means (1') (self-weight seating state), conventional problems 1 (wear due to pressing on the valve body and accompanying rotation when seating) and conventional problems 2 (reduced sealing performance due to inclination of the valve body sealing surface and valve seat sealing surface) can be simultaneously resolved, thereby improving reliability. Furthermore, in the third embodiment of the electric shut-off valve 100c, similar to the second embodiment, by employing a pressing force adjustment shut-off means (2') (additional self-weight seating state) and a pressing force adjustment shut-off means (3') (biased seating state), the pressing force of the valve body 42'' against the valve seat part 10a can be adjusted, thereby more reliably shutting off the flow path. Furthermore, in the third embodiment of the electric shut-off valve 100c, by employing a rotation suppression means (2') (where the valve body is loosely fitted and supported relative to the drive shaft), the transmission of rotation of the drive shaft 30 to the valve body 42'' can be more reliably suppressed. In addition, in the third embodiment of the electric shut-off valve 100c, similar to the second embodiment, the axial gap tlc1 between the pressing portion 41ba'' of the support portion 41b'' and the valve body 42'' is set to be larger than the screw play C in the axial L direction of the screw feed mechanism (tlc1>C), thereby eliminating concerns (deviation in valve opening and closing operation). Furthermore, in the electric shut-off valve 100b of the third embodiment, similar to the second embodiment, by setting the axial gap tlc1 on one side to be larger than the axial gap tlc2 on the other side, the time until the valve is seated under its own weight can be increased. This makes it more reliable for the valve body sealing surface 42a'' to seat flush with the valve seat sealing surface 10aa due to the weight of the valve body 42'', and shortens the time from the added weight seating state to the biased seating state. As a result, the sealing performance between the valve seat sealing surface 10aa and the valve body sealing surface 42a'' can be improved more quickly. Moreover, in the electric shut-off valve 100c of the third embodiment, similar to the second embodiment, the maximum static friction force can be made relatively large by the pressing force adjustment shut-off means (3') (biased seating state). Therefore, it is possible to use a design where either the valve body sealing surface 42a'' or the valve seat sealing surface 10aa is made of a resin material and the other is made of a metal material.

[0146] In the third embodiment, all of the rotation suppression means (1'), (2') and the pressing force adjustment and blocking means (1') to (3') are employed, but the embodiment is not limited to this. For example, as long as at least the rotation suppression means (1') and the pressing force adjustment and blocking means (1') are employed simultaneously, the embodiment may not employ any of the rotation suppression means (2') or pressing force adjustment and blocking means (2'), (3'), or it may employ a combination that includes at least one of them.

[0147] Furthermore, in the third embodiment of the electric shut-off valve 100c, similar to the first embodiment, the concerns (vibration of the valve body due to turbulence occurring in the valve open state) can be eliminated by employing the flow straightening means of the valve body modifications 1 to 4.

[0148] <Other> It goes without saying that the electric shut-off valves 100a to 100c of this embodiment are applicable to all fluid devices and fluid circuits. Furthermore, the present invention is not limited to the above-described forms, embodiments, or modifications, and can be appropriately modified or altered without departing from the technical spirit of the present invention. [Explanation of Symbols]

[0149] 100a~100c Electric shut-off valve 1. First joint pipe 2. Second joint pipe 10 Valve body 10a Valve seat (valve seat) 10aa Valve seat sealing surface 10b Valve port 12 valve chambers 20 Support members 21 Holder part 22 Fixed part 23 screw holes 23a Female thread section (screw feed mechanism) 24 bearing holes 25 slide holes 26 Guide rails 30 Drive shaft 30a One end of the drive shaft 31 Threaded part 31a Male thread section (screw feeding mechanism) 32 Guide section 33 Waist area 34 Flange section 40,40',40'' Valve body 41,41',41'' Valve support 41a Information section 41b,41b'' Support part 41ba, 41ba'' Pressing part (contact part) 41bb'' Engagement part 41bc'' Reduced diameter part 42, 42, 42A~42D Valve body 42a, 42a'' Valve body sealing surface 42b,42b'' Pressed surface (contact part) 42Aa,42Ba protrusion 42Ca,42Da depression 42c Valve body flange section 42c'' lip piece 43 Engaging part 44 Washers 45,45' Spring support section 45a' Protruding section 46 Compression coil spring (compression spring) 47 Lid 50 Coil members 60 Stepping motors a. Radial clearance As containment space C-axis thread play D1 Inner diameter at the seating position of the valve seat sealing surface Outer diameter at the contact position of the D2 flange portion Ga gap region L axis L1 Guide length between guide section and slide hole Nc non-contact part tla1, tla1', tlb1, tlb1': Unilateral axial gap between the valve body and the support. tlb2, tlb2', tlc2, tlc2': The axial gap on the other side between the spring support and one end of the drive shaft. tlc1,tlc1': Unilateral axial gap between the valve body and the pressing portion of the support. tra1, trb1, trc1 First radial gap between the valve body and the engaging portion tra2, trb2 Second radial gap between the valve body and the support trc2 Second radial gap between the valve body and the reduced diameter portion T1 Axial opening gap between the valve seat sealing surface and the valve body T2 Axial clearance between flange portion and washer θ1: Inclination of the valve body with respect to the axis L, inclination of the valve body sealing surface with respect to the valve seat sealing surface, inclination of the washer with respect to the flange portion.

Claims

1. A drive shaft that can move in the axial direction, On the other end, there is a valve seat having a valve seat sealing surface, A valve body having a valve body with a valve body sealing surface on one end, A pressing force adjustment shutoff means for adjusting the pressing force of the valve body against the valve seat and shutting off the flow path, Equipped with, The shut-off valve is characterized in that the pressing force adjustment shut-off means has a configuration such that when the valve body seats on the valve seat, the valve body's own weight causes the valve body's sealing surface to sit flush with the valve seat's sealing surface in a self-weight seating state.

2. The system further includes rotation suppression means for preventing the rotation of the drive shaft from being transmitted to the valve body. The valve body portion comprises a valve support having a cylindrical guide portion and a support portion for supporting the valve body, a spring receiving portion housed in the guide portion and capable of contacting one end of the drive shaft, and a compression spring sandwiched between the spring receiving portion and the support portion. The shut-off valve according to claim 1, characterized in that the rotation suppression means has a configuration in which the valve body is loosely fitted and supported with respect to the support portion of the valve support when the valve body is seated on the valve seat.

3. The shut-off valve according to claim 2, further comprising a configuration in which, when the valve body sealing surface is seated flush with the valve seat sealing surface, one end of the drive shaft presses the spring receiving portion against the biasing force of the compression spring, thereby causing the valve body sealing surface to be pressed against the valve seat sealing surface via the axial contact portion of the support portion of the valve body and the valve support, resulting in a biased seating state.

4. The shut-off valve according to claim 3, further comprising a configuration in which the pressing force adjustment shut-off means, simultaneously with the biased seating state, or between the self-weight seating state and the biased seating state, enters an additional self-weight seating state in which the valve body sealing surface is seated flush with the valve seat sealing surface due to the self-weight of the valve body and the valve support.

5. The shut-off valve according to claim 3, further comprising a configuration in which, in the biased seated state, one end of the drive shaft is not clamped axially by the valve body.

6. The shut-off valve according to claim 2, further comprising a configuration in which the valve support is loosely fitted and supported with respect to one end of the drive shaft when the valve body is seated on the valve seat.

7. The shut-off valve according to claim 2, characterized in that, in a suspended state in which the valve body is loosely fitted and supported with respect to the support portion of the valve support, the axial gap on one side between the valve body and the support portion is set to be larger than the axial screw play of the drive shaft.

8. The shut-off valve according to claim 7, characterized in that, in a suspended state in which the valve support is loosely fitted and supported on one end of the drive shaft, and the valve body is loosely fitted and supported on the support portion of the valve support, the axial gap on one side between the valve body and the support portion is set to be larger than the axial gap on the other side between the valve support and one end of the drive shaft.

9. The shut-off valve according to claim 3, characterized in that either the valve body sealing surface or the valve seat sealing surface is made of a resin material, and the other is made of a metal material.

10. The shut-off valve according to claim 1, further comprising a flow straightening means consisting of a projection or recess extending along the axis on the valve body sealing surface.

11. The holder portion further comprises a screw hole that engages with the drive shaft and a slide hole into which the guide portion of the valve support is slidably engaged, arranged in the axial direction. Let tla1 be the axial gap on one side between the support portion and the valve body, a be the radial clearance between the guide portion and the slide hole of the valve support, L1 be the guide length formed by the guide portion and the slide hole of the valve support, and D1 be the inner diameter of the valve seat sealing surface at the seating position. The shut-off valve according to claim 2, characterized in that tla1 > a × D1 / L1.

12. The valve body portion has an engaging portion that is fitted into and fixed to the support portion of the valve support, The valve body has a first radial gap tra1 between itself and the engaging portion, and a second radial gap tra2 between itself and the support portion of the valve support. The shut-off valve according to claim 2, characterized in that tra2 > tra1.

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