Shut-off valve

Abstract

To provide a shut-off valve adopting a screw feeding mechanism as driving means for the shut-off valve, and capable of improving the durability and sealability of a valve element seal surface and a valve seat seal surface to improve the reliability.SOLUTION: The shut-off valve includes a drive shaft 30 movable with the screw feeding mechanism, a valve seat part 10a, a valve element part 40 having a valve element 42, a valve support 41, a spring receiving part 45, and a compression spring 46, rotation suppression means for suppressing transmission of rotation of the drive shaft 30 to the valve element 42, and pressing force adjustment chut-off means for adjusting the pressing force of the valve element 42 on the valve seat part 10a to cut off a flow path. The rotation suppression means is constructed so that the valve element 42 is loosely fitted to and supported on the valve support 41 when the valve element 42 is seated on the valve seat part 10a. The pressing force adjustment cut-off means is constructed so that the valve element seal surface 42a is set in a self-weight seated state of being seated with the self-weight of the valve element 42 while being flush with the valve seat seal surface 10aa when the valve element 42 is seated on the valve seat part 10a.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a shutoff valve equipped with a rotation suppressing means and a pressing force adjusting shutoff means. [Background technology]

[0002] Some shutoff valves use a solenoid as their actuation means to improve the responsiveness of the valve opening and closing operation, but the solenoid must be energized to maintain either the open or closed state. This means that when these shutoff valves are actually used, the running costs are relatively high, and in the unlikely event of a power outage, there is a risk of the valve temporarily losing function. To solve this problem, some shutoff valves use a screw feed mechanism as their actuation means.

[0003] 11, Patent Document 1 discloses a shutoff valve 1100 (hereinafter referred to as a "conventional shutoff valve") that includes 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 an 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. The 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. The valve body portion 1140 has a valve support portion 1141 that holds one end of the drive shaft 1130 in the direction of the axis L, and a valve body 1142 that has a disk-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 thought that a screw feed mechanism is employed as an example. This screw feed mechanism is configured such that a female thread and a male thread formed on the inner peripheral surface of the other end of the support member 1120 and the outer peripheral surface of the other end of the drive shaft 1130 are threadedly engaged with each other, thereby allowing the drive shaft 1130 to move in the direction of the axis L while rotating together with the valve body portion 1140.

[0005] In such a conventional shut-off valve 1100, when the valve element 1142 seats on the valve seat 1110aa, the valve element 1142, which rotates along with the drive shaft 1130, is pressed against the valve seat 1110aa while rotating, resulting in extremely large wear on the sealing surfaces of the valve element 1142 and the valve seat 1110aa (hereinafter referred to as "conventional problem 1 (wear due to rotation and pressure on the valve element when seated)")).

[0006] In addition, like a general shutoff valve, the conventional shutoff valve 1100 also has a certain degree of assembly error because the drive shaft 1130 and the valve body portion 1140 are connected to the manifold 1110 via the support member 1120. Therefore, in the conventional shutoff 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, 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 the valve body sealing surface and the valve seat sealing surface)"). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Chinese Patent Application Publication No. 114233914 Summary of the Invention [Problem to be solved by the invention]

[0008] The object of the present invention is to provide a shutoff valve that employs a screw feed mechanism as a drive means for the shutoff valve, and that focuses particularly on the seating time, thereby improving the durability and sealing performance of the valve body sealing surface and the valve seat sealing surface, thereby improving reliability. [Means for solving the problem]

[0009] In order to solve the above problems, a valve support body is provided, which includes a drive shaft that can be moved in the axial direction as it rotates by a screw feed mechanism, a valve seat having an annular valve seat seal surface at the other end, a valve body portion having a valve body having a disk-shaped valve body seal surface at one end, a cylindrical guide portion and a support portion that supports the valve body, a spring receiving portion that is accommodated in the guide portion and can abut against one end of the drive shaft, and a compression spring that is sandwiched between the spring receiving portion and the support portion, and the rotation of the drive shaft is a rotation suppression means for suppressing rotation from being transmitted 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 so that when the valve body sits on the valve seat, the valve body is supported by a loose fit relative to the support portion of the valve support body, and the pressing force adjustment shut-off means is configured so that when the valve body sits on the valve seat, the weight of the valve body causes the valve body seal surface to sit flush with the valve seat seal surface, resulting in a weight-seated state.

[0010] Furthermore, in the above-described shut-off valve, the pressing force adjusting shut-off means 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 the spring receiving portion against the biasing force of the compression spring, thereby bringing about a biased seating state in which the valve body sealing surface is pressed against the valve seat sealing surface via the axial abutment portion of the valve body and the support portion of the valve support body.

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

[0012] In the above shutoff valve, the rotation suppressing means may further have a configuration in which one end of the drive shaft is not clamped axially by the valve body portion in the biased seated state.

[0013] Furthermore, in the above-described shutoff valve, the rotation suppression means may further have a configuration in which the valve support is supported with a loose fit relative 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 on the support portion of the valve support body, the axial gap on one side between the valve body and the support portion may be set to be larger than the axial thread play of the drive shaft.

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

[0016] In the above shutoff 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] The above-described shutoff valve may further include a flow straightening means formed of a protrusion or a recess extending along the axis on the valve body sealing surface. [Effects of the Invention]

[0018] According to the present invention, in a shut-off valve that employs a screw feed mechanism as a drive means, it is possible to provide a shut-off valve that can improve reliability by focusing particularly on the seating time and improving the durability and sealing performance of the valve body sealing surface and the valve seat sealing surface. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a vertical cross-sectional view showing an electrically operated cutoff valve according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a partial enlarged view of the area surrounded by the dashed line II shown in FIG. [Figure 3] 3 is an explanatory diagram of the valve closing operation of the motor-operated shutoff valve shown in FIG. 2, where (a) shows the suspended state, (b) shows the gravity seating state, (c) shows the transition state, and (d) shows the additional gravity seating state and the biased seating state. [Figure 4] 4A and 4B are explanatory diagrams illustrating the valve closing operation of the motor-operated shutoff valve when the valve support body shown in FIG. 3 is tilted relative to the axis, where FIG. 4A shows a partially seated state and FIG. 4B shows a gravity seated state. [Figure 5] 1A and 1B are explanatory diagrams (hanging state) of valve body variants 1 to 4 in the first embodiment, where (a) shows valve body variant 1 (frustum-shaped protrusion), (b) shows valve body variant 2 (cylindrical protrusion), (c) shows valve body variant 3 (conical recess), and (d) shows valve body variant 4 (cylindrical recess). [Figure 6] 10 is a longitudinal cross-sectional view (corresponding to FIG. 2) showing an electrically operated cutoff valve according to a second embodiment. [Figure 7] 7A to 7D are explanatory diagrams of the valve closing operation of the motor-operated shutoff valve shown in FIG. 6, where (a) shows the suspended state, (b) shows the weight-seated state, (c) shows the additional weight-seated state, and (d) shows the biased seating state. [Figure 8] 8A and 8B are explanatory diagrams of the valve closing operation of the motor-operated shutoff valve when the valve support body shown in FIG. 7 is tilted relative to the axis, where FIG. 8A shows a dead-weight seating state and FIG. 8B shows an additional dead-weight seating state. [Figure 9] 10 is a longitudinal cross-sectional view (corresponding to FIG. 6) showing an electrically operated cutoff valve according to a third embodiment. [Figure 10] 10A to 10D are explanatory diagrams of the valve closing operation of the motor-operated shutoff valve shown in FIG. 9, where (a) represents a suspended state, (b) represents a weight-seated state, (c) represents an additional weight-seated state, and (d) represents a biased seating state. [Figure 11] FIG. 1 is a vertical cross-sectional view showing a shutoff valve according to a conventional technique. DETAILED DESCRIPTION OF THE INVENTION

[0020] An embodiment of the present invention will be described in detail with reference to Figures 1 to 10. Note that although the following description will be directed to an electrically operated shutoff valve, the rotation suppression means and pressing force adjustment shutoff means of the present invention are not limited to electrically operated shutoff valves and can be applied to any shutoff valve, such as a manual shutoff valve.

[0021] <Terminology> In this specification and claims, the terms "left," "right," "upper," and "lower" refer to the directions shown in Figures 1 to 10. In this specification and claims, the terms "one end" and "other end" refer to the "lower end" and "upper end" in the drawings. In this specification and claims, the term "rotation suppression means" refers to suppressing the transmission of rotation of the drive shaft to the valve disc. In this specification and claims, the term "pressure adjustment and shut-off means" refers to adjusting the pressure of the valve disc against the valve seat to shut off the flow path. In this specification and claims, the term "loosely fitted support" refers to two components fitted together with some play, with a gap between the two components allowing relative movement in the radial and axial directions. In this specification and claims, the term "suspended state" refers to a state in which the valve disc 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 claims, the term "weight seating state" refers to a state in which the valve disc is supported with a loose fit when seated on the valve seat, and the weight of the valve disc causes the valve disc seal surface to be seated flush with the valve seat seal surface. In this specification and claims, the term "added weight seating state" refers to a state in which the valve support is supported with a loose fit, and the weight of the valve disc and the valve support causes the valve disc seal surface to be seated flush with the valve seat seal surface. In this specification and claims, the term "biased seating state" refers to a state in which the valve disc seal surface is seated flush with the valve seat seal surface, and the biasing force of the compression coil spring presses the valve disc seal surface against the valve seat seal surface. In this specification and the claims, the term "disk-shaped valve body seal surface" refers to a valve body seal surface that is disk-shaped when viewed from the axial direction, and refers to a disk-shaped valve body seal surface that has a protrusion or recess extending along the axis in addition to a flat disk-shaped valve body seal surface.

[0022] (First embodiment) <Configuration of the electric shutoff valve> 1 and 2, an electric shutoff valve 100a according to a first embodiment of the present invention will be described. The electric shutoff valve 100a is mainly composed of a valve body 10, a support member 20, a drive shaft 30, a valve body portion 40, a coil member 50, and a stepping motor 60. Each component of the electric shutoff valve 100a will be described below in order. Although details will be described later, the electric shutoff valve 100a of the first embodiment employs a rotation suppression means (1) (the valve body is supported by a loose fit relative to the support member) and a pressing force adjustment shutoff means (1) (a state in which the valve body is seated by its own weight), thereby simultaneously resolving both conventional problem 1 (wear due to pressure on the valve body when seated and accompanying rotation) and conventional problem 2 (reduced sealing performance due to inclination of the valve body sealing surface and the valve seat sealing surface) and improving reliability.

[0023] The valve body 10 is formed into 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 10a that stands annularly facing the other side in the direction of the axis L. A valve port 10b is opened at the center of the valve seat 10a, and an annular valve seat seal surface 10aa is formed at the other end. A valve chamber 12 is also formed inside the valve seat 10a.

[0024] A first coupling pipe 1 serving as a fluid flow path is connected to one outer periphery of the valve body 10, and this first coupling pipe 1 is in communication with a valve chamber 12. A second coupling pipe 2 is connected to the bottom side of the valve body 10, and this second coupling pipe 2 is in communication with the valve chamber 12 via a valve port 10b. The first coupling pipe 1 and the second coupling pipe 2 are made of a material such as copper or stainless steel, and are fixed to the valve body 10.

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

[0026] The holder portion 21 is arranged so that its axis overlaps with the axis L that passes through the axis of the valve port 10b. A threaded hole 23, a bearing hole 24, and a slide hole 25 are concentrically formed in the center of the holder portion 21 and aligned in the direction of the axis L so as to pass through the holder portion 21. A female thread portion 23a is formed on the inner peripheral surface of the threaded hole 23, and a male thread portion 31a of the drive shaft 30, which will be described later, is threadedly engaged with the inner peripheral surface of the bearing hole 24. A guide portion 32 of the drive shaft 30, which will be described later, is slidably engaged with the inner peripheral surface of the bearing hole 24. The slide hole 25 is arranged closer to the valve port 10b and has a larger diameter than the bearing hole 24. A valve body portion 40, which will be described later, is slidably engaged with the slide hole 25.

[0027] Guide rails 26 consisting of spiral ridges are integrally formed on the outer peripheral surface of holder portion 21. Adjacent winding portions of guide rail 26 are arranged with a gap between them. Guide rail 26 is arranged so that its axis overlaps axis L, and guides each winding portion of coil portion 51 from one or both sides so that coil portion 51 of coil member 50 (described later) is threadedly engaged therewith and coil member 50 can rotate in the circumferential direction.

[0028] The drive shaft 30 is formed into a cylindrical rod shape using a metal such as stainless steel. The drive shaft 30 is formed with a threaded portion 31, a guide portion 32, a constricted portion 33, and a flange portion 34, which are arranged in this order along the axis L. The threaded portion 31 is formed with a male threaded portion 31a, which is threadedly engaged with a female threaded portion 23a of the holder portion 21 to form a screw feed mechanism, converting the rotational motion of the drive shaft 30 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 along the axis L. As a result, the drive shaft 30 is moved along the axis L as well as rotated by the screw feed action of the screw feed mechanism. The flange portion 34 rotatably engages 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-handed threads.

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

[0030] The valve support body 41 is engaged with the slide hole 25 so as to be slidable in the direction of the axis 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 that is 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 spreads outward in the radial direction and extends toward the one end.

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

[0032] The engaging portion 43 has an annular shape with an L-shaped cross section, and is fitted and fixed to the support portion 41b of the valve support body 41. The valve body 42 is loosely fitted and supported between the engaging portion 43 and the support portion 41b of the valve support body 41, with gaps 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 lid portion 47 is fitted and fixed to the other end of the valve support 41 so that the washer 44 is sandwiched between the lid portion 47 and the flange portion 34 of the drive shaft 30 (see FIG. 3(a)). The lid portion 47 is positioned opposite the neck portion 33 of the drive shaft 30. As a result, the drive shaft 30 hooks the valve support 41 via the flange portion 34, allowing the valve support 41 to rotate about the axis L of the valve support 41 and move in the direction of the axis L. The inner diameter of the lid portion 47 is set larger than the outer diameter of the neck portion 33 of the drive shaft 30. A spring bearing 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 attached in a compressed state with a predetermined load applied between the spring receiving portion 45 and the support portion 41b of the valve support body 41. As a result, the spring receiving portion 45 is biased toward the other end and abuts against one end 30a of the drive shaft 30.

[0034] The coil member 50 integrally includes a coil spring-shaped coil portion 51 and a claw portion 52 protruding radially outward from one end of the coil portion 51. The coil portion 51 is threadedly engaged with the guide rail 26 of the holder portion 21 so as to be rotatable in the circumferential direction. The claw portion 52 can abut against a protrusion 67 of the magnet rotor 62 (described later). 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 rotation of the coil member 50 and the magnet rotor 62. This restricts movement of the valve body 40 beyond the position where the valve is fully open or the position where the valve is closed. The coil member 50 can be easily manufactured by molding a metal wire such as stainless steel.

[0035] The stepping motor 60 includes 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 has a generally cylindrical shape with a closed upper end. 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 whose outer periphery is magnetized with multiple poles, and a disk portion 65 that closes one end of the magnet portion 64. The magnet rotor 62 is fixed to the drive shaft 30 via a metal fitting 66 that is integrally molded in the center of the disk portion 65. This allows the magnet rotor 62 to rotate around the axis of the drive shaft 30 within the case 61. The drive shaft 30 is the rotation axis of the magnet rotor 62.

[0038] The stator coil is disposed on the outer peripheral surface of the case 61, and when a pulse signal is given to the stator coil, the magnet rotor 62 is rotated in accordance with 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 feed action of the male thread portion 31a and the female thread portion 23a (screw feed mechanism) moves the drive shaft 30 in the direction of the axis L, causing the valve body portion 40 to advance and retreat relative to the valve seat portion 10a. This causes the valve body seal surface 42a and the valve seat seal surface 10aa to come into contact with and separate from each other, thereby controlling the flow of fluid from the first joint pipe 1 to the second joint pipe 2.

[0040] <Regarding conventional problems 1 and 2> As described above, the conventional shutoff valve 1100 shown in Fig. 11 employs a screw feed mechanism. Therefore, when the valve disc 1142 seats on the valve seat 1110aa, the valve disc 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 the accompanying rotation and pressing of the valve disc when seated). Furthermore, the conventional shutoff valve 1100 has assembly errors, so when the valve disc 1142 seats on the valve seat 1110aa, the valve disc sealing surface and the valve seat sealing surface are not completely flush, resulting in conventional problem 2 (deterioration of sealing performance due to inclination of the valve disc sealing surface and the valve seat sealing surface).

[0041] Therefore, the conventional shut-off valve 1100 simultaneously has conventional problem 1 (wear due to accompanying 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 may result in reduced reliability.

[0042] In contrast to this, the electric shutoff valve 100a of the first embodiment employs a rotation suppression means (1) (the valve body is supported by a loose fit relative to the support portion) and a pressing force adjustment shutoff means (1) (seated by its own weight), thereby simultaneously resolving the conventional problem 1 (wear due to pressure on the valve body when seated and accompanying rotation) and the conventional problem 2 (reduced sealing performance due to inclination of the valve body sealing surface and the valve seat sealing surface).

[0043] <Details of valve closing operation> Next, the valve closing operation of the motorized shutoff valve 100a (suspended state, gravity seating state, transition state, additional seating state, and biased seating state) will be explained in order using FIG. 3. The explanation will be made while showing the rotation suppression means (1) and (2) that suppress the transmission of rotation of the drive shaft 30 to the valve disc 42 during this valve closing operation, and the pressing force adjusting shutoff means (1) to (3) that adjust the pressing force of the valve disc 42 against the valve seat portion 10a to shut off the flow path. Since the valve closing operation of the motorized shutoff valve 100a is symmetrical in FIG. 3, only the left side will be used for explanation. Furthermore, since the valve opening operation is the reverse of the valve closing operation, only the valve closing operation will be explained here. Furthermore, when viewed from the direction of the axis L, the valve seat seal surface 10aa is completely covered by the valve disc seal surface 42a.

[0044] <About the hanging state> The suspended state will be described with reference to Figure 3(a). In the suspended state, the valve body portion 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 portion 40 moves in the direction of the axis L (see arrow M1 in Figure 3(a)) while rotating together with the drive shaft 30. Note that the valve body seal surface 42a of the valve body 42 is separated from the valve seat seal surface 10aa of the valve seat portion 10a.

[0045] At this time, the valve element 42 is placed on the engaging portion 43 via the valve element flange portion 42c, and has a first radial gap tra1 between it and the engaging portion 43, and also has a one-side axial gap tla1 and a second radial gap tra2 between it and the support portion 41b of the valve support body 41. Here, the second radial gap tra2 is set larger than the first radial gap tra1 (tra2>tra1). Note that 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 element 42, so that the valve element 42 is suspended from the valve support body 41.

[0046] <About the self-weighted seated state> The gravity-seated state will be described with reference to Figure 3(b). In the gravity-seated state, the valve body 40 is integrally connected to the drive shaft 30 by clamping one end of the drive shaft 30, as in 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 seal surface 42a of the valve body 42 abuts against the valve seat seal surface 10aa of the valve seat portion 10a.

[0047] Rotation suppression means (1) (valve body supported by loose fit in support part) The rotation suppression means (1) (valve body loosely 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 relative to the support portion 41b and the engagement portion 43 of the valve support body 41, and is loosely supported so as to be movable in the radial direction and the axial direction L.

[0048] Specifically, the valve disc flange portion 42c of the valve disc 42 is separated from the engaging portion 43, and a one-side axial gap tla1' remains between the pressing portion 41ba of the support portion 41b and the pressed surface 42b of the valve disc 42, forming a gap region Ga. Therefore, when the valve disc 42 seats on the valve seat 10a, the rotation suppression means (1) (the valve disc is supported by a loose fit relative to the support portion) causes the valve disc 42 to be out of contact with the valve support body 41 and the engaging portion 43 and to be loosely supported so as to be movable in the radial direction and the axial direction L. In this way, the rotation suppression means (1) (the valve disc is supported by a loose fit relative to the support portion) functions like a clutch, completely cutting off the connection between the valve disc 42 and the valve support body 41 and the engaging portion 43, i.e., the connection between the valve disc 42 and the drive shaft 30. This solves the conventional problem 1 (wear due to pressure on the valve disc and co-rotation when seated).

[0049] -About the pressure adjustment shutoff means (1) (self-weight seating state) The pressure adjusting shut-off means (1) (self-weight seating state) is configured such that when the valve body 42 seats on the valve seat portion 10a, the valve body 42's own weight causes the valve body seal surface 42a to seat flush with the valve seat seal surface 10aa, resulting in a self-weight seating state.

[0050] Specifically, in the suspended state of the motor-operated shutoff valve 100a (see FIG. 3(a)), due to assembly errors and the like, the valve disc seal surface 42a and the valve seat seal surface 10aa are not arranged parallel to each other, but are tilted to one another to some extent. In this case, when the valve disc 42 is seated on the valve seat 10a by the pressing force adjusting shutoff means (1) (weight seating state), the weight of the valve disc 42 causes the valve disc seal surface 42a to seat along the valve seat seal surface 10aa, and so they autonomously become flush with each other, thereby solving the conventional problem 2 (reduced sealing performance due to tilting of the valve disc seal surface and the valve seat seal surface).

[0051] As described above, in the electric shutoff valve 100a of the first embodiment, by simultaneously employing a rotation suppression means (1) (the valve body is supported by a loose fit relative to the support portion) and a pressing force adjustment shutoff means (1) (in a state in which the valve body is seated by its own weight), it is possible to simultaneously solve the conventional problem 1 (wear due to the pressure on the valve body when seated and accompanying rotation) and the conventional problem 2 (reduced sealing performance due to the inclination of the valve body sealing surface and the valve seat sealing surface), thereby improving reliability.

[0052] <About the transition state> The transition state will be described with reference to FIG. 3(c). The transition state indicates a momentary state in which the valve element 40 moves in the axial direction L (see arrow M3 in FIG. 3(c)) together with the drive shaft 30 while rotating, causing the pressing portion 41ba of the support portion 41b to abut against the pressed surface 42b of the valve element 42. Therefore, in the transition state, the valve element 40 is integrally connected to the drive shaft 30 by clamping one end of the drive shaft 30, similar to the weight-seated state. Therefore, the valve element 42 is not supported with a loose fit, but is clamped in the axial direction L by the valve support 41 and the valve seat portion 10a. At this time, because the valve support 41 is supported by the drive shaft 30, the weight of the valve support 41 is not applied to the valve element seal surface 42a. Therefore, in the transition state, the valve disc seal surface 42a is pressed against the valve seat seal surface 10aa by the weight of the valve disc 42, similar to the weight-seated state (see FIG. 3(b)).

[0053] Note that the transition state is a momentary state during movement of the drive shaft 30 in the direction of the axis L (see arrow M3 in FIG. 3(c)), and therefore consideration of the rotation suppression means and the pressing force adjustment / cutoff means will be omitted.

[0054] <Additional weight seating state and biased seating state> The additional weight seating state and the biased seating state will be described with reference to FIG. 3(d). The additional weight seating state and the biased seating state occur simultaneously. First, the drive shaft 30 rotates and moves in the direction of the axis L (see arrow M4 in FIG. 3(d)). However, the valve support 41 abuts against the valve seat portion 10a via the valve body 42 and cannot move in the direction of the axis L together with the drive shaft 30. Therefore, the drive shaft 30 presses the spring bearing portion 45 against the biasing force of the compression coil spring 46 and moves in the direction of the axis L (see arrow M4 in FIG. 3(d)) while rotating. This releases the clamping of one end of the drive shaft 30 by the valve body portion 40. In addition, the valve body seal surface 42a of the valve body 42 is in an additional weight seating state where it is pressed against the valve seat seal surface 10aa of the valve seat portion 10a by the weight of the valve body 42 as well as the weight of the valve support body 41, and is also in a biased seating state where it is pressed by the biasing force of the compression coil spring 46.

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

[0056] Specifically, when the drive shaft 30 presses the spring receiving portion 45 against the biasing force of the compression coil spring 46 and moves in the direction of the axis L while rotating (see arrow M4 in FIG. 3(d)), the clamping of one end of the drive shaft 30 by the valve body portion 40 is released like a clutch. Because of this rotation suppression means (2) (the drive shaft is not clamped by the valve body portion), the transmission path of the rotational force from the drive shaft 30 to the valve body 42 must pass through the spring receiving portion 45, the compression coil spring 46, and the support portion 41b, and sliding friction occurs due to the relative rotation between these components. 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 electric shutoff valve 100a of the first embodiment, in addition to the rotation suppression means (1) (the valve body is supported loosely in the support portion), by adopting the rotation suppression means (2) (the drive shaft is not clamped in the valve body portion), it is possible to more reliably suppress the rotation of the drive shaft 30 from being transmitted to the valve body 42.

[0058] Regarding the pressure adjusting cutoff means (2) (additional weight seating state) and the pressure adjusting cutoff means (3) (biased seating state) The pressing force adjusting shutoff means (2) (additional weight seating state) is configured to support the valve support body 41 with a loose fit, and to be in an additional weight seating state in which the valve body seal surface 42a is seated flush with the valve seat seal surface 10aa due to the weight of the valve body 42 and the valve support body 41. The pressing force adjusting shutoff means (3) (biased seating state) is configured to be in a biased seating state in which the valve body seal surface 42a is pressed against the valve seat seal surface 10aa by the biasing force of the compression coil spring 46, when the valve body seal surface 42a is seated flush with the valve seat seal surface 10aa.

[0059] Specifically, the motor-operated shutoff valve 100a transitions from a gravity seating state (see FIG. 3(b)) through an instantaneous transition state (see FIG. 3(c)), to an additional gravity seating state and a biased seating state (see FIG. 3(d)). In the gravity seating state (see FIG. 3(b)), the weight of the valve element 42 presses the valve element seal surface 42a against the valve seat seal surface 10aa in a completely stationary state. Thereafter, when transitioning to the additional gravity seating state and the biased seating state (see FIG. 3(d)), the clamping of one end of the drive shaft 30 by the valve element portion 40 is released like a clutch. At this time, the weight of the valve body 42 and the valve support body 41 acts so that the valve body seal surface 42a is pressed against the valve seat seal surface 10aa by the pressing force adjusting and shutting means (2) (additional weight seating state), and the biasing force of the compression coil spring 46 acts so that the valve body seal surface 42a is pressed against the valve seat seal surface 10aa by the pressing force adjusting and shutting means (3) (biased seating state).

[0060] As a result, in the electric shutoff valve 100a of the first embodiment, in addition to the pressing force adjusting shutoff means (1) (dead weight seating state), by employing the pressing force adjusting shutoff means (2) (additional dead weight seating state) and the pressing force adjusting shutoff means (3) (biased seating state), it is possible to adjust the pressing force of the valve body 42 against the valve seat portion 10a and more reliably shut off the flow path.

[0061] <Considerations based on maximum static friction force> In the motor-operated shutoff valve 100a of the first embodiment, in the weight-seated state (see FIG. 3(b)), the valve disc 42 is completely stationary relative to the valve seat 10a. Here, in the additional weight-seated state and the biased seated state (see FIG. 3(d)), in order for the valve disc 42 to remain completely stationary relative to the valve seat 10a, the rotational force applied to the valve disc 42 by the drive shaft 30 needs to be equal to or less than the maximum static friction force (fmax=μN: static friction coefficient μ, normal force N) of the valve disc 42 with respect to the valve seat 10a.

[0062] Here, particularly, from the moment the valve element 42 assumes the biased seating state shown in FIG. 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 element 42 by the pressure adjusting / shutting off means (3) (biased seating state). Furthermore, as the drive shaft 30 rotates and moves in the axial direction L (see arrow M4 in FIG. 3(d)), the biasing force (normal force N) of the compression coil spring 46 on the valve element 42 rapidly increases, resulting in a relatively large maximum static friction force (fmax = μN). As a result, even if the valve element 42 or the valve seat 10a is made of a resin material with a relatively small static friction coefficient μ and high slidability, the valve element 42 can remain completely stationary relative to the valve seat 10a in the weight-loaded seating state and the biased seating state (see FIG. 3(d)).

[0063] As a result, in the first embodiment, one of the valve disc 42 (i.e., the valve disc sealing surface 42a) and the valve seat 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, in consideration of high sliding properties, the resin material in the first embodiment may be, for example, polytetrafluoroethylene (PTFE), perfluoroalkoxyalkane (PFA), nylon, acetal, polyimide (PI), polyester, or the like. Furthermore, in consideration of wear resistance, processability, and the like, the resin material in the first embodiment may be, for example, polytetrafluoroethylene (PTFE), perfluoroalkoxyalkane (PFA), or polyphenylene sulfide (PPS), polyetheretherketone (PEEK), polyamide (PA), nylon, or the like, to which an additive (such as graphite, molybdenum, or carbon fiber) has been added.

[0064] <About the axial clearance on one side that absorbs the inclination of the valve support body> Next, the one-side axial gap tla1 that absorbs the inclination of the valve body 40 in the motorized cutoff valve 100a of the first embodiment will be described in detail with reference to Fig. 4. Note that Fig. 4 illustrates an example in which the valve body 40 is inclined with respect to the axis L, but the same explanation can be applied to cases in which the drive shaft 30 is inclined or in which both the valve support body 41 and the drive shaft 30 are inclined.

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

[0066] Here, as shown in Figure 4(a), when the guide length formed by the guide portion 41a of the valve support body 41 and the slide hole 25 is L1, and the radial clearance between the guide portion 41a of the valve support body 41 and the slide hole 25 is a, the inclination θ1 of the valve body portion 40 is calculated as follows (Equation 1). tanθ1=a / L1 (Equation 1)

[0067] Furthermore, assuming that the inner diameter of the valve seat seal surface 10aa at the seating position is D1 and the axial opening gap between the valve seat seal surface 10aa and the valve body 42 is T1, the inclination θ1 of the valve body seal surface 42a relative to the valve seat seal surface 10aa is calculated as follows (Equation 2): tanθ1=T1 / D1 (Equation 2)

[0068] In addition, in Figure 4(a), by setting the one-side 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 seal surface 10aa and the valve body 42, as shown in the following (Equation 3), it is possible to reliably cause the valve body 42 to rotate in a loose-fit support state (see M2m in Figure 4(b)) until it seats on the valve seat portion 10a. tla1>T1 (Equation 3)

[0069] Here, by substituting (Equation 1) and (Equation 2) into (Equation 3), the following (Equation 4) can be obtained. tla1>a×D1 / L1 (Formula 4)

[0070] Therefore, in the motor-operated cutoff valve 100a of the first embodiment, in order to absorb the inclination θ1 of the valve body portion 40, the one-side axial clearance tla1 is set so as to satisfy the relational expression (Equation 4), thereby ensuring the rotational movement of the valve body 42 (see M2m in FIG. 4(b)). Note that although there is no set upper limit to the one-side axial clearance tla1, if it becomes too large, the responsiveness of the valve closing operation and the valve opening operation will be significantly reduced, so it is preferable to set it so as to satisfy, for example, 0.05 mm≦tla1≦0.4 mm.

[0071] Next, in FIG. 4(b), as the drive shaft 30 rotates and moves in the axial L direction (see arrow M2 in FIG. 4(b)), the valve disc flange portion 42c of the valve disc 42 moves away from the valve support body 41 and the engagement portion 43 in the axial L direction. At this time, as described above, because the one-side axial gap tla1 is set larger than the axial opening gap T1 (see FIG. 4(a) and (Equation 3)), the valve disc 42 is supported with a loose fit (see non-contact portion Nc in FIG. 4(b)) relative to the valve support body 41 and the engagement portion 43 so as to be movable in the radial direction and the axial L direction, and a gap region Ga is formed. As a result, the valve disc 42 can reliably rotate in the loose fit support (see M2m in FIG. 4(b)) due to its own weight until it seats on the valve seat portion 10a.

[0072] As shown in Fig. 3(a), the valve element 42 has a first radial gap tra1 between it and the engagement portion 43, and a second radial gap tra2 between it and the support portion 41b of the valve support body 41. By setting the second radial gap tra2 larger than the first radial gap tra1 (tra2>tra1), the valve element 42 can more reliably rotate in the loose-fit support state (see M2m in Fig. 4(b)) until it seats on the valve seat portion 10a.

[0073] <About the axial clearance on one side that absorbs axial screw play> 3(a), the one-side axial gap tla1 that absorbs the thread backlash C (not shown) in the axial direction of the motor-operated cutoff valve 100a of the first embodiment will be described in detail. Here, a case where the thread backlash C in the axial direction of the axis L is present in the screw feed mechanism formed by the male thread portion 31a and the female thread portion 23a (see FIG. 1) of the drive shaft 30 will be described as an example, but the same explanation can be made even if the drive shaft 30 is displaced from the desired mounting position in the axial direction of the axis L due to an assembly error.

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

[0075] 3(a), when the valve element 42 is suspended from the support portion 41b of the valve support body 41, the one-side axial gap tla1 between the support portion 41b and the valve element 42 is set to be larger than the thread 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 one-side axial gap tla1 without depending on the thread play C in the axial L direction, thereby eliminating the concern (deviation of the valve opening and closing operation).

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

[0077] <Regarding concerns (vibration of the valve disc due to turbulence when the valve is open)> As shown in Figure 3(a), in the valve open state, the valve disc 42 is suspended from the support portion 41b of the valve support body 41. At this time, fluid flows from the radially outer side to the radially inner side of the valve disc seal surface 42a of the valve disc 42, and collides violently with the central portion on the axis L. This causes turbulence in the vicinity of the valve disc 42, which has raised concerns that the valve disc 42 may vibrate relative to the support portion 41b (hereinafter referred to as "concern (vibration of the valve disc due to turbulence occurring in the valve open state)").

[0078] In contrast, in valve body variations 1 to 4 of the first embodiment, a straightening means consisting of protrusions 42Aa, 42Ba or recesses 42Ca, 42Da extending along the axis L is provided on the valve body seal surface 42a of the valve bodies 42A to 42D.

[0079] (Variations 1 to 4 of this valve body) 5(a) to 5(d), valve bodies 42A to 42D in valve body modifications 1 to 4 of the first embodiment will be described. First, in valve body modification 1, a flow straightening device consisting of a truncated conical protrusion 42Aa extending along the axis L is provided on the valve body seal surface 42a of valve body 42A. In valve body modification 2, a flow straightening device consisting of a cylindrical protrusion 42Ba extending along the axis L is provided on the valve body seal surface 42a of valve body 42B. Furthermore, in valve body modification 3, a flow straightening device consisting of a conical recess 42Ca extending along the axis L is provided on the valve body seal surface 42a of valve body 42C. Additionally, in valve body modification 4, a flow straightening device consisting of a cylindrical recess 42Da extending along the axis L is provided on the valve body seal surface 42a of valve body 42D.

[0080] As described above, the valve bodies 42A to 42D in the present valve body modifications 1 to 4 of the first embodiment are provided with the protrusions 42Aa, 42Ba and recesses 42Ca, 42Da that extend along the axis L as flow straightening means. This flow straightening means smoothly deflects the flow of fluid from the radially outer side to the radially inner side of each valve body seal surface 42a to a flow to one side in the direction of the axis L, thereby eliminating the concern (vibration of the valve body due to turbulence that occurs when the valve is open).

[0081] As described above, the motor-operated shutoff valve 100a of the first embodiment employs both the rotation suppression means (1) (the valve disc is supported by a loose fit relative to the support portion) and the pressing force adjusting shutoff means (1) (weight-seated state) to simultaneously solve the conventional problem 1 (wear due to the pressure on the valve disc and accompanying rotation when seated) and the conventional problem 2 (deterioration of sealing performance due to inclination of the valve disc seal surface and the valve seat seal surface), thereby improving reliability. Furthermore, the motor-operated shutoff valve 100a of the first embodiment employs the pressing force adjusting shutoff means (2) (additional weight-seated state) and the pressing force adjusting shutoff means (3) (biased-seated state) to adjust the pressing force of the valve disc 42 against the valve seat portion 10a, thereby more reliably shutting off the flow path. Furthermore, the motor-operated shutoff valve 100a of the first embodiment employs the rotation suppression means (2) (the drive shaft is not clamped by the valve disc portion) to more reliably suppress transmission of rotation of the drive shaft 30 to the valve disc 42. Additionally, in the motor-operated cutoff valve 100a of the first embodiment, the one-side axial gap tla1 between the support portion 41b and the valve element 42 is set to be larger than the thread backlash C in the axial direction L of the screw feed mechanism (tla1>C), thereby eliminating the concern (deviation of the valve opening and closing operation). Also, in the motor-operated cutoff valve 100a of the first embodiment, the pressing force adjusting cutoff means (3) (biased seating state) can make the maximum static friction force relatively large, so that one of the valve element seal surface 42a and the valve seat seal surface 10aa can be made of a resin material, and the other can be made of a metal material.

[0082] In the first embodiment, the rotation suppressing means (1), (2) and all of the pressing force adjusting and shutting means (1) to (3) are employed, but this is not limiting. For example, as long as at least the rotation suppressing means (1) and the pressing force adjusting and shutting means (1) are employed simultaneously, it is also possible to employ neither the rotation suppressing means (2) nor the pressing force adjusting and shutting means (2), (3), or to employ a combination including at least one of them.

[0083] Furthermore, in the valve element modifications 1 to 4 of the motor-operated cutoff valve 100a of the first embodiment, by employing flow rectification means in the valve elements 42A to 42D, it is possible to eliminate the concern (vibration of the valve element due to turbulence occurring in the valve open state).

[0084] (Second embodiment) An electric shutoff valve 100b according to a second embodiment will be described using Figures 6 to 8. The electric shutoff valve 100b according to the second embodiment differs from the electric shutoff valve 100a according to the first embodiment in that a protruding portion 45a' is provided on a spring receiving portion 45', but other basic configurations are the same as those of the first embodiment. Here, the same components are given the same reference numerals, and duplicated explanations will be omitted.

[0085] <Configuration of the electric shutoff valve> An electric shutoff valve 100b according to a second embodiment of the present invention will be described using Figure 6. The electric shutoff valve 100b is mainly composed of a valve body 10, a support member 20 (see Figure 1), a drive shaft 30, a valve body portion 40', a coil member 50 (see Figure 1), and a stepping motor 60 (see Figure 1). Below, a spring bearing portion 45' of the valve body portion 40', which differs from the electric shutoff valve 100a of the first embodiment, will be described.

[0086] <About the spring support> The spring receiving portion 45' further includes a ring-shaped protruding portion 45a' on the other end side. This protruding portion 45a' abuts against the washer 44. As will be described in detail later, the length of the protruding portion 45a' in the axial direction L is set to be greater than the length of the drive shaft 30 in the axial direction L from one end 30a to the other end of the flange portion 34. Therefore, as a rotation suppressing means (2'), when the valve disc 42 is seated on the valve seat 10a, the valve support 41 is supported with loose fit relative to the one end 30a of the drive shaft 30 so as to be movable in the radial and axial directions.

[0087] <Details of valve closing operation> Next, the valve closing operation of the motorized cutoff valve 100b (suspended state, gravity seating state, transition state, additional seating state, and biased seating state) will be explained in order using Figure 7. The explanation will be made while showing rotation suppression means (1) and (2') that suppress the rotation of the drive shaft 30 from being transmitted to the valve element 42 during this valve closing operation, and pressing force adjusting cutoff means (1) to (3) that adjust the pressing force of the valve element 42 against the valve seat portion 10a and cut off the flow path. Note that in the second embodiment, rotation suppression means (2') is used instead of the rotation suppression means (2) in the first embodiment.

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

[0089] In this case, the valve element 42 is placed on the engagement portion 43 via the valve element flange portion 42c, and has a first radial gap trb1 between it and the engagement portion 43, and a one-side axial gap tlb1 and a second radial gap trb2 between it and the support portion 41b of the valve support body 41. In addition, an other-side axial gap tlb2 is formed between the spring bearing portion 45' and one end 30a of the drive shaft 30. Here, the one-side axial gap tlb1 is set larger than the other-side axial gap tlb2 (tlb1>tlb2). Note that the second radial gap trb2 is set larger than the first radial gap trb1 (trb2>trb1), as in the first embodiment.

[0090] <About the self-weighted seated state> The gravity-seated state will be described with reference to Figure 7(b). In the gravity-seated state, the valve element 40' is loosely fitted and supported on one end 30a of the drive shaft 30, as in the suspended state, so as to be movable in the radial direction and the axial direction L. As a result, the valve element 40' moves in the axial direction L (see arrow M2' in Figure 7(b)) together with the drive shaft 30 while rotating, and the valve element seal surface 42a of the valve element 42 abuts against the valve seat seal surface 10aa of the valve seat portion 10a. At this time, there is still a one-side axial gap tlb1' between the pressing portion 41ba of the support portion 41b and the pressed surface 42b of the valve element 42, and a gap region Ga is formed.

[0091] Rotation suppression means (1) (valve body supported by loose fit in support part) The rotation suppression means (1) (the valve element is loosely fitted and supported relative to the support portion) has a configuration in which, as in the first embodiment, when the valve element 42 is seated on the valve seat portion 10a, the valve element 42 is in a non-contact state with the support portion 41b of the valve support body 41 and is loosely fitted and supported so as to be movable in the radial direction and the direction of the axis L. By employing this rotation suppression means (1) (the valve element is loosely fitted and supported relative to the support portion), it is possible to solve the conventional problem 1 (wear due to pressure on the valve element and co-rotation when seated).

[0092] Rotation restraint means (2') (valve body part loosely fitted to the drive shaft) The rotation suppression means (2') (the valve body portion is loosely fitted and supported on the drive shaft) has a configuration in which the valve body portion 40' is loosely fitted and supported on 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 second embodiment of the electric shutoff valve 100b, in addition to the rotation suppression means (1) (the valve body is supported by a loose fit relative to the support portion), a rotation suppression means (2') (the valve body portion is supported by a loose fit relative to the drive shaft) is adopted, thereby more reliably suppressing the rotation of the drive shaft 30 from being transmitted to the valve body 42.

[0094] -About the pressure adjustment shutoff means (1) (self-weight seating state) The pressing force adjusting shutoff means (1) (gravity seating state) has a configuration in which, when the valve element 42 is seated on the valve seat portion 10a, the valve element seal surface 42a is seated flush with the valve seat seal surface 10aa due to the weight of the valve element 42, thereby achieving a gravity seating state, as in the first embodiment. By employing this pressing force adjusting shutoff means (1) (gravity seating state), it is possible to solve the conventional problem 2 (decrease in sealing performance due to inclination of the valve element seal surface and the valve seat seal surface).

[0095] As described above, in the motorized cutoff valve 100b of the second embodiment, similarly to the first embodiment, by simultaneously employing a rotation suppression means (1) (the valve disc is supported by a loose fit relative to the support portion) and a pressing force adjusting cutoff means (1) (seated by its own weight), it is possible to simultaneously solve the conventional problem 1 (wear due to the pressure on the valve disc when seated and accompanying rotation) and the conventional problem 2 (deterioration of sealing performance due to inclination of the valve disc sealing surface and the valve seat sealing surface), thereby improving reliability. Also, in the motorized cutoff valve 100b of the second embodiment, by employing a rotation suppression means (2') (the valve disc portion is supported by a loose fit relative to the drive shaft), it is possible to more reliably suppress transmission of rotation of the drive shaft 30 to the valve disc 42.

[0096] <Additional dead weight seated state> The additional weight seating state will be described with reference to FIG. 7(c). First, the valve element portion 40' moves in the axial direction L (see arrow M3' in FIG. 7(c)) together with the drive shaft 30 while rotating, causing the pressing portion 41ba of the support portion 41b to abut against the pressed surface 42b of the valve element 42. Then, the drive shaft 30 moves further in the axial direction L (see arrow M3' in FIG. 7(c)) while rotating, causing the drive shaft 30 to come out of contact with the valve element portion 40'. At this time, an axial gap tlb2' is formed between the spring bearing portion 45' and the one end 30a of the drive shaft 30. Therefore, the valve element seal surface 42a of the valve element 42 is pressed against the valve seat seal surface 10aa of the valve seat portion 10a by the weight of the valve support body 41 in addition to the weight of the valve element 42, resulting in an additional weight seating state.

[0097] Rotation restraint means (2') (valve body part loosely fitted to the drive shaft) The rotation suppression means (2') (the valve body portion is loosely fitted and supported on the drive shaft) has a configuration in which the valve body portion 40' is in a non-contact state with one end 30a of the drive shaft 30, similar to the weight-seated state, and is loosely fitted and supported so as to be movable in the radial direction and the axial L direction.

[0098] As a result, in the second embodiment of the electric shutoff valve 100b, in addition to the rotation suppression means (1) (the valve body is supported by a loose fit relative to the support portion), a rotation suppression means (2') (the valve body portion is supported by a loose fit relative to the drive shaft) is adopted, thereby more reliably suppressing the rotation of the drive shaft 30 from being transmitted to the valve body 42.

[0099] -About the pressure adjustment cutoff means (2) (additional dead weight seating state) The pressure adjusting shut-off means (2) (additional dead-weight seating state) is configured in the same way as in the first embodiment, such that the valve support body 41 is supported with a loose fit, and the weight of the valve body 42 and the valve support body 41 causes the valve body seal surface 42a to be seated flush with the valve seat seal surface 10aa in an additional dead-weight seating state.

[0100] As a result, in the motor-operated cutoff valve 100b of the second embodiment, by employing the pressing force adjusting cutoff means (2) (additional weight seating state) in addition to the pressing force adjusting cutoff means (1) (weight seating state), it is possible to adjust the pressing force of the valve element 42 against the valve seat portion 10a and more reliably shut off the flow path.

[0101] <Regarding the energized seating state> The biased seating state will be described with reference to Figure 7(d). Here, the drive shaft 30 moves in the direction of the axis L (see arrow M4' in Figure 7(d)) ​​while rotating, and comes into contact with the spring receiving portion 45', pressing the spring receiving portion 45' against the biasing force of the compression coil spring 46. As a result, the valve disc seal surface 42a of the valve disc 42 is pressed against the valve seat seal surface 10aa of the valve seat 10a by the biasing force of the compression coil spring 46, entering a biased seating state.

[0102] Rotation restraint means (2') (valve body part loosely fitted to the drive shaft) The rotation suppression means (2') (the valve body portion is loosely fitted and supported on the drive shaft) has a configuration in which the valve body portion 40' is loosely fitted and supported on 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 weight-seated state.

[0103] As a result, in the second embodiment of the electric shutoff valve 100b, in addition to the rotation suppression means (1) (the valve body is supported by a loose fit relative to the support portion), a rotation suppression means (2') (the valve body portion is supported by a loose fit relative to the drive shaft) is adopted, thereby more reliably suppressing the rotation of the drive shaft 30 from being transmitted to the valve body 42.

[0104] Regarding the pressure adjusting cutoff means (2) (additional weight seating state) and the pressure adjusting cutoff means (3) (biased seating state) The pressing force adjusting and shutting means (2) (additional weight seating state) is configured, as in the first embodiment, so that the valve support body 41 is supported with a loose fit, and the valve disc seal surface 42a is placed in an additional weight seating state in which it is seated flush with the valve seat seal surface 10aa due to the weight of the valve disc 42 and the valve support body 41. Also, the pressing force adjusting and shutting means (3) (biased seating state) is configured, as in the first embodiment, so that, in a state in which the valve disc seal surface 42a is seated flush with the valve seat seal surface 10aa, the biasing force of the compression coil spring 46 presses the valve disc seal surface 42a against the valve seat seal surface 10aa.

[0105] As a result, in the electric shutoff valve 100b of the second embodiment, in addition to the pressing force adjusting shutoff means (1) (dead weight seating state), by employing the pressing force adjusting shutoff means (2) (additional dead weight seating state) and the pressing force adjusting shutoff means (3) (biased seating state), it is possible to adjust the pressing force of the valve body 42 against the valve seat portion 10a and more reliably shut 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 adjusting shutoff means (3) (biased seating state), so that one of the valve body 42 (i.e., valve body seal surface 42a) and the valve seat portion 10a (i.e., valve seat seal surface 10aa) can be made of a resin material, and the other can be made of a metal material. Also, as in the first embodiment, the resin material in the second embodiment may be, for example, polytetrafluoroethylene (PTFE), perfluoroalkoxyalkane (PFA), nylon, acetal, polyimide (PI), polyester, etc., in consideration of high slidability. Furthermore, as in the first embodiment, the resin material in the second embodiment may be polytetrafluoroethylene (PTFE), perfluoroalkoxyalkane (PFA), or the like, or polyphenylene sulfide (PPS), polyether ether ketone (PEEK), polyamide (PA), nylon, or the like, to which additives (graphite, molybdenum, carbon fiber, or the like) have been added, taking into consideration abrasion resistance, processability, and the like.

[0107] <Regarding the axial clearance on the other side that absorbs the inclination of the valve support body> Next, the other-side axial gap tlb2 that absorbs the inclination of the valve body 40' in the motorized cutoff valve 100b of the second embodiment will be described in detail with reference to Figure 8. Note that Figure 8 illustrates an example in which the valve body 40' is inclined with respect to the axis L, but the same explanation can be applied to cases in which the drive shaft 30 is inclined or in which both the valve support body 41 and the drive shaft 30 are inclined.

[0108] As shown in FIG. 7(a), the motor-operated shutoff valve 100b of the second embodiment has a one-side axial gap tlb1 and an other-side axial gap tlb2. When the valve support 41′ transitions from the dead-weight seating state to the additional dead-weight seating state, the one-side axial gap tlb1 first absorbs any inclination of the valve support 41′, and then the other-side axial gap tlb2 absorbs any further inclination of the valve support 41′. However, since the explanation of how the one-side axial gap tlb1 absorbs the inclination of the valve support 41′ overlaps with the above-mentioned “One-side axial gap absorbing the inclination of the valve support,” it will be omitted here. Here, the explanation will focus on how the other-side axial gap tlb2 absorbs the inclination of the valve support 41′. Therefore, FIG. 8(a) corresponds to FIG. 4(b).

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

[0110] As shown in Figure 8(a), when the guide length formed by the guide portion 41a of the valve support body 41 and the slide hole 25 is L1, and the radial clearance between the guide portion 41a of the valve support body 41 and the slide hole 25 is a, the inclination θ1 of the valve body portion 40' is calculated as shown in (Equation 1) above. tanθ1=a / L1 (Equation 1)

[0111] Furthermore, when the outer diameter of the flange portion 34 at the contact position is D2, and the axial gap between the flange portion 34 and the washer 44 is T2, the inclination θ1 of the washer 44 relative to the flange portion 34 is calculated as follows (Equation 5). tanθ1=T2 / D2 (Equation 5)

[0112] In addition, in Figure 8(a), by setting the other-side axial gap tlb2 between the spring support 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 the following (Equation 6), it is possible to reliably cause a rotational movement in the loose-fit support (see M3m' in Figure 8(b)) until the pressing portion 41ba of the valve support body 41 abuts against the pressed surface 42b of the valve body 42. tlb2>T2 (Formula 6)

[0113] Here, by substituting (Equation 1) and (Equation 5) into (Equation 6), the following (Equation 7) can be obtained. tlb2>a×D2 / L1 (Formula 7)

[0114] Therefore, in the motor-operated cutoff valve 100b of the second embodiment, in order to absorb the inclination θ1 of the valve body 40′, the other-side axial clearance tlb2 is set so as to satisfy the relational expression (Equation 7), thereby ensuring the rotational movement of the valve body 40′ (see M3m′ in FIG. 8(b)). Note that although there is no upper limit set for the other-side axial clearance tlb2, if it becomes too large, the responsiveness of the valve closing and opening movements will decrease significantly, so it is preferable to set it so as to satisfy, for example, 0.01 mm≦tlb2≦0.1 mm.

[0115] Next, in FIG. 8(b), as the drive shaft 30 rotates and moves in the axial L direction (see arrow M3' in FIG. 8(b)), the drive shaft 30 comes into a non-contact state with the valve body 40' (see non-contact portion Nc in FIG. 8(b)). At this time, as described above, the other-side axial gap tlb2 is set larger than the axial gap T2 (see FIG. 8(a) and (Equation 6)). Therefore, the valve body 40' is loosely supported (see non-contact portion Nc in FIG. 8(b)) relative to the drive shaft 30 so as to be movable in the radial direction and the axial L direction. As a result, the weight of the valve body 40' can reliably cause the valve body 40' to rotate in the loosely supported state (see M3m' in FIG. 8(b)) until the pressing portion 41ba of the valve support 41 abuts against the pressed surface 42b of the valve body 42.

[0116] Furthermore, as shown in Figure 7(a), by setting the second radial gap trb2 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 more reliably caused until the valve body 42 seats on the valve seat portion 10a.

[0117] In the second embodiment, the one-side axial gap tlb1 shown in Fig. 7(a) is set larger than the other-side axial gap tlb2. This allows the time from when the valve disc 42 seats on the valve seat 10a until it reaches its own weight seating state to be relatively longer than the time from when it reaches the additional weight seating state to when it reaches the biased seating state. This lengthens the time until it reaches its own weight seating state, thereby more reliably seating the disc seal surface 42a flush with the valve seat seal surface 10aa due to the weight of the valve disc 42. Furthermore, this shortens the time it takes to transition from the additional weight seating state to the biased seating state, thereby more quickly improving the sealing performance between the valve seat seal surface 10aa and the valve disc seal surface 42a.

[0118] As described above, the motor-operated shutoff valve 100b of the second embodiment employs, as in the first embodiment, a rotation suppression means (1) (where the valve element is supported by a loose fit relative to the support portion) and a pressing force adjusting shutoff means (1) (in a weight-seated state), thereby simultaneously solving the conventional problem 1 (wear due to pressure on the valve element and accompanying rotation when seated) and the conventional problem 2 (deterioration of sealing performance due to inclination of the valve element seal surface and the valve seat seal surface), thereby improving reliability. Also, as in the first embodiment, the motor-operated shutoff valve 100b employs a pressing force adjusting shutoff means (2) (in an additional weight-seated state) and a pressing force adjusting shutoff means (3) (in a biased seated state), thereby adjusting the pressing force of the valve element 42 against the valve seat portion 10a, thereby more reliably shutting off the flow path. Furthermore, the motor-operated shutoff valve 100b of the second embodiment employs a rotation suppression means (2') (where the valve element portion is supported by a loose fit relative to the drive shaft), thereby more reliably suppressing transmission of rotation of the drive shaft 30 to the valve element 42. Additionally, in the motor-operated shutoff valve 100b of the second embodiment, as in the first embodiment, the one-side axial gap tla1 between the support portion 41b and the valve element 42 is set to be larger than the thread backlash C in the axial direction L of the screw feed mechanism (tla1>C), thereby eliminating the concern (deviation of the valve opening and closing operation). Also, in the motor-operated shutoff valve 100b of the second embodiment, the one-side axial gap tlb1 is set to be larger than the other-side axial gap tlb2, thereby lengthening the time until the weight-seated state is achieved, thereby more reliably seating the valve element seal surface 42a flush with the valve seat seal surface 10aa due to the weight of the valve element 42 and shortening the time it takes to change from the additional weight-seated state to the biased seated state, thereby more quickly improving the sealing performance between the valve seat seal surface 10aa and the valve element seal surface 42a. Furthermore, in the motor-operated shutoff valve 100b of the second embodiment, the pressing force adjusting shutoff means (3) (biased seating state) can make the maximum static friction force relatively large, so that one of the valve body sealing surface 42a and the valve seat sealing surface 10aa can be made of a resin material, and the other can be made of a metal material.

[0119] In the second embodiment, the rotation suppressing means (1), (2') and all of the pressing force adjusting and shutting means (1) to (3) are employed, but this is not limiting. For example, as long as at least the rotation suppressing means (1) and the pressing force adjusting and shutting means (1) are employed simultaneously, it is also possible to employ none of the rotation suppressing means (2') and the pressing force adjusting and shutting means (2), (3), or to employ a combination including at least one of them.

[0120] Furthermore, in the second embodiment of the motor-operated shut-off valve 100b, as in the first embodiment, by adopting the rectification means of the present valve body variations 1 to 4, it is possible to eliminate the concern (vibration of the valve body due to turbulence that occurs when the valve is open)

[0121] (Third embodiment) An electric shutoff valve 100c according to a third embodiment will be described using Figures 9 and 10. The electric shutoff valve 100c according to the third embodiment differs from the electric shutoff valve 100b according to the second embodiment in that the support portion 41b'' of the valve support body 41'' has a structure that supports the inside of the valve body 42'' with a loose fit, but other basic configurations are the same as those of the second embodiment. Here, the same configurations are given the same reference numerals, and duplicated explanations will be omitted.

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

[0123] <About the valve support> The valve support 41'' is engaged with the slide hole 25 so as to be slidable in the direction of the axis L, and has a guide portion 41a and a support portion 41b'' provided at one side end of the guide portion 41a. The guide portion 41a is formed in a cylindrical shape with an outer diameter that is approximately 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'' that is smaller in diameter than the guide portion 41a, a disk-shaped engagement portion 41bb'' provided at one end side of the reduced diameter portion 41bc'', and a pressing portion 41ba'' provided at a step between the guide portion 41a and the reduced diameter portion 41bc''.

[0124] The valve element 42'' is made of, for example, a resin material or a metal such as stainless steel, and has an upwardly facing C-shaped cross section that defines the accommodation space As. The valve element 42'' has a disk-shaped valve element sealing surface 42a'' provided at one end, a C-shaped pressed surface 42b'' provided at the other end, and a lip piece 42c'' provided at the other end and extending radially inward. Here, the valve element 42'' is supported with a loose fit by having gaps in the radial and axial directions between the accommodation space As and the support portion 41b''.

[0125] <Details of valve closing operation> Next, the valve closing operation of the motorized cutoff valve 100c (suspended state, gravity seating state, transition state, additional seating state, and biased seating state) will be explained in order using FIG. 10. The explanation will be made while showing rotation suppression means (1′) and (2′) that suppress the rotation of the drive shaft 30 from being transmitted to the valve disc 42″ during this valve closing operation, and pressing force adjusting cutoff means (1′) to (3′) that adjust the pressing force of the valve disc 42″ against the valve seat portion 10a and cut off the flow path. Note that the third embodiment differs from the second embodiment only in the loose-fit support structure between the valve support body 41″ and the valve disc 42″, and therefore the rotation suppression means (1′) and (2′) and pressing force adjusting cutoff means (1′) to (3′) are the same as the rotation suppression means (1), (2′) and pressing force adjusting cutoff means (1) to (3) in the second embodiment.

[0126] <About the hanging state> The suspended state will be described with reference to FIG. 10(a). As in the second embodiment, in the suspended state, the valve body portion 40'' is supported with a loose fit relative to one end 30a of the drive shaft 30 so as to be movable in the radial direction and the axial direction L by sandwiching a washer 44 between the spring receiving portion 45' and the cover portion 47 with the biasing force of a compression coil spring 46 applied. As a result, the valve body portion 40'' moves in the axial direction L (see arrow M1'' in FIG. 10(a)) while rotating together with the drive shaft 30. Note that the valve body seal surface 42a'' of the valve body 42'' is separated from the valve seat seal surface 10aa of the valve seat portion 10a.

[0127] In this case, the valve element 42'' is placed on the engagement portion 41bb'' via the lip piece 42c'', and has a first radial gap trc1 between itself and the engagement portion 41bb'', a second radial gap trc2 between itself and the reduced-diameter portion 41bc'', and a one-side axial gap tlc1 between itself and the pressing portion 41ba'' of the support portion 41b''. In addition, an other-side axial gap tlc2 is formed between the spring bearing portion 45' and one end 30a of the drive shaft 30. Here, the one-side axial gap tlc1 is set larger than the other-side axial gap tlb2 (tlc1>tlc2). In addition, the second radial gap trc2 is set larger than the first radial gap trc1 (trc2>trc1), as in the second embodiment. This more reliably enables the valve element 42'' to rotate until it is completely seated on the valve seat 10a in the weight-seated state.

[0128] <About the self-weighted seated state> The gravity-seated state will be described with reference to Figure 10(b). In the gravity-seated state, the valve element 40" is supported with a loose fit relative to one end 30a of the drive shaft 30, as in the suspended state, so as to be movable in the radial direction and the axial direction L. As a result, the valve element 40" moves in the axial direction L (see arrow M2" in Figure 10(b)) together with the drive shaft 30 while rotating, and the valve element seal surface 42a" of the valve element 42" comes into contact with the valve seat seal surface 10aa of the valve seat portion 10a. At this time, there is still a one-side axial gap tlc1' between the pressing portion 41ba" of the support portion 41b" and the pressed surface 42b" of the valve element 42".

[0129] Rotation restraining means (1') (valve body loosely fitted to the support part) The rotation suppression means (1') (the valve disc is loosely fitted and supported relative to the support portion) has a configuration in which, as in the second embodiment, when the valve disc 42'' is seated on the valve seat portion 10a, the valve disc 42'' is out of contact with the support portion 41b'' of the valve support body 41'' and is loosely fitted and supported so as to be movable in the radial direction and the direction of the axis L. By employing this rotation suppression means (1') (the valve disc is loosely fitted and supported relative to the support portion), it is possible to solve the conventional problem 1 (pressure on the valve disc when seated and wear due to co-rotation).

[0130] Rotation restraint means (2') (valve body part loosely fitted to the drive shaft) The rotation suppression means (2') (the valve body portion is loosely fitted and supported on the drive shaft) has a configuration in which the valve body portion 40'' is loosely fitted and supported on one end 30a of the drive shaft 30 so as to be movable in the radial direction and the axial direction L, as in the second embodiment.

[0131] As a result, in the electric shutoff valve 100c of the third embodiment, in addition to the rotation suppression means (1') (the valve body is supported by a loose fit relative to the support portion) as in the second embodiment, a rotation suppression means (2') (the valve body portion is supported by a loose fit relative to the drive shaft) is adopted, thereby more reliably suppressing the rotation of the drive shaft 30 from being transmitted to the valve body 42''.

[0132] -About the pressure adjustment shutoff means (1') (in the weight seated state) The pressing force adjusting shutoff means (1') (gravity seating state) has a configuration in which, when the valve disc 42'' is seated on the valve seat portion 10a, the valve disc seal surface 42a'' is seated flush with the valve seat seal surface 10aa due to the weight of the valve disc 42'', thereby achieving a gravity seating state, as in the second embodiment. By employing this pressing force adjusting shutoff means (1') (gravity seating state), it is possible to solve the conventional problem 2 (reduced sealing performance due to inclination of the valve disc seal surface and the valve seat seal surface).

[0133] As described above, the motorized shutoff valve 100c of the third embodiment, like the second embodiment, employs a rotation suppression means (1') (the valve disc is supported by a loose fit relative to the support portion) and a pressing force adjustment shutoff means (1') (seated by its own weight), thereby simultaneously resolving both conventional problem 1 (wear due to the pressure on the valve disc when seated and accompanying rotation) and conventional problem 2 (deterioration of sealing performance due to inclination of the valve disc seal surface and the valve seat seal surface), thereby improving reliability. Also, like the second embodiment, the motorized shutoff valve 100c of the third embodiment employs a rotation suppression means (2') (the valve disc portion is supported by a loose fit relative to the drive shaft), thereby more reliably suppressing the rotation of the drive shaft 30 from being transmitted to the valve disc 42''.

[0134] <Additional dead weight seated state> The additional weight seating state will be described with reference to FIG. 10(c). First, the valve element portion 40'' moves in the axial direction L (see arrow M3'' in FIG. 10(c)) together with the drive shaft 30 while rotating, causing the pressing portion 41ba'' of the support portion 41b'' to come into contact with the pressed surface 42b'' of the valve element 42''. Then, the drive shaft 30 moves further in the axial direction L (see arrow M3'' in FIG. 10(c)) while rotating, causing the drive shaft 30 to come out of contact with the valve element portion 40''. At this time, an axial gap tlc2' is formed between the spring bearing portion 45' and the one end 30a of the drive shaft 30. Therefore, the valve element seal surface 42a'' of the valve element 42'' is pressed against the valve seat seal surface 10aa of the valve seat portion 10a by the weight of the valve support 41'' as well as the weight of the valve element 42''.

[0135] Rotation restraint means (2') (valve body part loosely fitted to the drive shaft) The rotation suppression means (2') (the valve body portion is loosely fitted and supported on the drive shaft) has a configuration in which the valve body portion 40'' is loosely fitted and supported on one end 30a of the drive shaft 30 in a non-contact state and is movable in the radial direction and the axial direction L, as in the second embodiment.

[0136] As a result, in the electric shutoff valve 100c of the third embodiment, in addition to the rotation suppression means (1') (the valve body is supported by a loose fit relative to the support portion), by adopting a rotation suppression means (2') (the valve body portion is supported by a loose fit relative to the drive shaft), it is possible to more reliably suppress the rotation of the drive shaft 30 from being transmitted to the valve body 42''.

[0137] -About the pressure adjusting cutoff means (2') (additional dead weight seating state) The pressing force adjusting shut-off means (2') (additional weight seating state) is configured, as in the second embodiment, so that the valve support body 41'' is supported with a loose fit, and the weight of the valve body 42'' and the valve support body 41'' causes the valve body seal surface 42a'' to be seated flush with the valve seat seal surface 10aa in an additional weight seating state.

[0138] As a result, in the motor-operated cutoff valve 100b of the third embodiment, by employing a pressing force adjusting cutoff means (2') (additional weight seating state) in addition to the pressing force adjusting cutoff means (1') (weight seating state), it is possible to adjust the pressing force of the valve element 42'' against the valve seat portion 10a and more reliably shut off the flow path.

[0139] <Regarding the energized seating state> The biased seating state will be described with reference to Figure 10(d). Here, the drive shaft 30 moves in the direction of the axis L (see arrow M4" in Figure 10(d)) while rotating, and comes into contact with the spring receiving portion 45', pressing the spring receiving portion 45' against the biasing force of the compression coil spring 46. As a result, the valve disc seal surface 42a" of the valve disc 42" is pressed against the valve seat seal surface 10aa of the valve seat 10a by the biasing force of the compression coil spring 46, entering a biased seating state.

[0140] Rotation restraint means (2') (valve body part loosely fitted to the drive shaft) The rotation suppression means (2') (the valve body portion is loosely fitted and supported on the drive shaft) has a configuration in which the valve body portion 40'' is loosely fitted and supported on one end 30a of the drive shaft 30 so as to be movable in the radial direction and the axial direction L, as in the second embodiment.

[0141] As a result, in the electric shutoff valve 100c of the third embodiment, in addition to the rotation suppression means (1') (the valve body is supported by a loose fit relative to the support portion), by adopting a rotation suppression means (2') (the valve body portion is supported by a loose fit relative to the drive shaft), it is possible to more reliably suppress the rotation of the drive shaft 30 from being transmitted to the valve body 42''.

[0142] - Regarding the pressure adjusting cutoff means (2') (in the weight seated state) and the pressure adjusting cutoff means (3') (in the biased seated state) The pressing force adjusting and shutting means (2') (additional weight seating state) is configured, as in the second embodiment, so that the valve support body 41'' is supported with a loose fit, and the weight of the valve body 42'' and the valve support body 41'' causes the valve body seal surface 42a'' to be seated flush with the valve seat seal surface 10aa, resulting in an additional weight seating state. Also, the pressing force adjusting and shutting means (3') (biased seating state) is configured, as in the second embodiment, so that, in a state in which the valve body seal surface 42a'' is seated flush with the valve seat seal surface 10aa, the biasing force of the compression coil spring 46 causes the valve body seal surface 42a'' to be pressed against the valve seat seal surface 10aa.

[0143] As a result, in the electric shutoff valve 100c of the third embodiment, in addition to the pressing force adjusting shutoff means (1') (weight seating state), a pressing force adjusting shutoff means (2') (additional weight seating state) and a pressing force adjusting shutoff means (3') (biased seating state) are employed, thereby adjusting the pressing force of the valve body 42'' against the valve seat portion 10a and more reliably shutting off the flow path.

[0144] In the third embodiment, as in the second embodiment, the pressing force adjusting and shutting means (3') (biased seating state) can make the maximum static friction force relatively large, so that one of the valve body 42'' (i.e., the valve body seal surface 42a'') and the valve seat portion 10a (i.e., the valve seat seal surface 10aa) can be made of a resin material, and the other can be made of a metal material. As in the second embodiment, the resin material in the third embodiment may be, for example, polytetrafluoroethylene (PTFE), perfluoroalkoxyalkane (PFA), nylon, acetal, polyimide (PI), polyester, etc., in consideration of high slidability. Furthermore, as in the first embodiment, the resin material in the second embodiment may be polytetrafluoroethylene (PTFE), perfluoroalkoxyalkane (PFA), or the like, or polyphenylene sulfide (PPS), polyether ether ketone (PEEK), polyamide (PA), nylon, or the like, to which additives (graphite, molybdenum, carbon fiber, or the like) have been added, taking into consideration abrasion resistance, processability, and the like.

[0145] As described above, the motorized cutoff valve 100c of the third embodiment employs, as in the second embodiment, a rotation suppression means (1') (where the valve disc is supported by a loose fit relative to the support portion) and a pressing force adjusting cutoff means (1') (in a weight-seated state) at the same time, thereby simultaneously resolving the conventional problem 1 (wear due to pressure on the valve disc and accompanying rotation when seated) and the conventional problem 2 (deterioration of sealing performance due to inclination of the valve disc sealing surface and the valve seat sealing surface), thereby improving reliability. Also, as in the second embodiment, the motorized cutoff valve 100c of the third embodiment employs a pressing force adjusting cutoff means (2') (in an additional weight-seated state) and a pressing force adjusting cutoff means (3') (in a biased seated state) to adjust the pressing force of the valve disc 42'' against the valve seat portion 10a, thereby more reliably shutting off the flow path. Furthermore, in the motorized cutoff valve 100c of the third embodiment, by employing a rotation suppression means (2') (the valve body portion is supported with a loose fit relative to the drive shaft), it is possible to more reliably suppress the rotation of the drive shaft 30 from being transmitted to the valve body 42''. In addition, in the motorized cutoff valve 100c of the third embodiment, as in the second embodiment, by setting the one-side axial gap tlc1 between the pressing portion 41ba'' of the support portion 41b'' and the valve body 42'' to be larger than the thread play C in the axial direction L of the screw feed mechanism (tlc1>C), it is possible to eliminate the concern (misalignment in the valve opening and closing operation). Furthermore, in the motor-operated shutoff valve 100b of the third embodiment, as in the second embodiment, by setting the one-side axial gap tlc1 larger than the other-side axial gap tlc2, the time until the weight-seated state is reached can be lengthened, which more reliably ensures that the valve disc seal surface 42a'' is seated flush with the valve seat seal surface 10aa due to the weight of the valve disc 42'' and shortens the time it takes to transition from the additional weight-seated state to the biased seated state, thereby more quickly improving the sealing performance between the valve seat seal surface 10aa and the valve disc seal surface 42a''. Furthermore, in the motor-operated shutoff valve 100c of the third embodiment, as in the second embodiment, the pressing force adjusting shutoff means (3') (biased seating state) can make the maximum static friction force relatively large, so that one of the valve disc seal surface 42a'' and the valve seat seal surface 10aa can be made of a resin material and the other can be made of a metal material.

[0146] In the third embodiment, the rotation suppressing means (1'), (2') and all of the pressing force adjusting and shutting means (1') to (3') are employed, but this is not limiting. For example, as long as at least the rotation suppressing means (1') and the pressing force adjusting and shutting means (1') are employed simultaneously, it is also possible to employ none of the rotation suppressing means (2') and the pressing force adjusting and shutting means (2'), (3'), or to employ a combination including at least one of them.

[0147] Furthermore, in the third embodiment, the electric shut-off valve 100c, like the first embodiment, employs the rectification means of the present valve body variations 1 to 4, thereby eliminating the concern (vibration of the valve body due to turbulence occurring when the valve is open).

[0148] <Other> It goes without saying that the motorized shutoff valves 100a to 100c of the present embodiment can be applied to any fluid device or fluid circuit. Furthermore, the present invention is not limited to the above-described aspects, embodiments, and modified examples, and can be appropriately changed or modified within the scope of the technical concept of the present invention. [Explanation of symbols]

[0149] 100a~100c Electric shutoff valve 1 First joint pipe 2 Second joint pipe 10 Valve body 10a Valve seat portion (valve seat) 10aa Valve seat sealing surface 10b Valve port 12 Valve chamber 20 Support member 21 Holder part 22 Fixed part 23 screw hole 23a Female thread (screw feed mechanism) 24 bearing hole 25 slide hole 26 Guide rail 30 Drive shaft 30a One end of the drive shaft 31 Threaded section 31a Male thread (screw feed mechanism) 32 Guide section 33 Waist 34 Flange 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 flange 42cm lip piece 43 Engagement part 44 Washer 45,45' spring support 45a' overhang 46 Compression coil spring (compression spring) 47 Lid 50 Coil material 60 stepping motor a Radial clearance As containment space C Axial screw play D1 Inner diameter of the valve seat seal surface at the seating position D2 Outer diameter of flange at contact point Ga gap region L axis L1: Guide length between the guide part and the slide hole Nc non-contact part tla1, tla1', tlb1, tlb1' One-side axial clearance between the valve body and the support tlb2, tlb2', tlc2, tlc2' Other side axial clearance between the spring bearing and one end of the drive shaft tlc1, tlc1' One-side axial clearance between the valve body and the pressing part of the support part tra1, trb1, trc1 First radial gap between the valve body and the engagement portion tra2, trb2: Second radial gap between the valve body and the support trc2: Second radial clearance between the valve body and the reduced diameter section T1 Axial opening clearance between the valve seat seal surface and the valve disc T2 Axial clearance between flange and washer θ1 Inclination of the valve body relative to the axis L, inclination of the valve body seal surface relative to the valve seat seal surface, inclination of the washer relative to the flange

Claims

1. a drive shaft that can move in an axial direction while rotating by a screw feed mechanism; a valve seat having an annular valve seat seal surface on the other end side; a valve body portion including a valve body having a disk-shaped valve body sealing surface on one end side, a valve support body including a cylindrical guide portion and a support portion that supports the valve body, a spring receiving portion that is housed in the guide portion and can abut against one end of the drive shaft, and a compression spring that is sandwiched between the spring receiving portion and the support portion; a rotation suppressing means for suppressing transmission of rotation of the drive shaft to the valve body; a pressure adjusting and shutting means for adjusting the pressure of the valve body against the valve seat to shut off the flow path; Equipped with the rotation suppressing means has a configuration in which the valve body is supported by a loose fit relative to the support portion of the valve support body when the valve body is seated on the valve seat, a valve body that is provided with a valve seat that is in a state of being seated flush with the valve seat sealing surface due to the valve body's own weight when the valve body is seated on the valve seat;

2. 2. The shutoff valve according to claim 1, further comprising a configuration in which, when the valve body seal surface is seated flush with the valve seat seal surface, one end of the drive shaft presses the spring receiving portion against the biasing force of the compression spring, thereby bringing about a biased seating state in which the valve body seal surface is pressed against the valve seat seal surface via an axial abutment portion of the valve body and the support portion of the valve support body.

3. 3. The shutoff valve according to claim 2, wherein the pressing force adjusting shutoff means further has a configuration in which, simultaneously with the biased seating state or between the biased seating state and the weight seating state, the pressing force adjusting shutoff means enters an additional weight seating state in which the valve body seal surface is seated flush with the valve seat seal surface due to the weight of the valve body and the valve support body.

4. 3. The shutoff valve according to claim 2, wherein the rotation suppressing means further comprises a configuration in which the one end of the drive shaft is not clamped axially by the valve body portion in the biased seated state.

5. 2. The shutoff valve according to claim 1, wherein the rotation suppressing means further comprises a configuration in which the valve support is supported with a loose fit relative to one end of the drive shaft when the valve body is seated on the valve seat.

6. 2. The shutoff valve according to claim 1, wherein, in a suspended state in which the valve body is loosely fitted and supported by the support portion of the valve support, an axial gap on one side between the valve body and the support portion is set to be larger than an axial thread play of the drive shaft.

7. 7. The shutoff valve according to claim 6, wherein, in a suspended state in which the valve support is loosely fitted and supported on one end of the drive shaft and the valve element is loosely fitted and supported on the support portion of the valve support, the one-side axial gap between the valve element and the support portion is set larger than the other-side axial gap between the valve support and one end of the drive shaft.

8. 3. The shutoff valve according to claim 2, wherein one of the valve body sealing surface and the valve seat sealing surface is made of a resin material, and the other is made of a metal material.

9. 2. The shutoff valve according to claim 1, further comprising a flow straightening means formed of a protrusion or a recess extending along the axis on the valve body sealing surface.

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