Motor valve

Abstract

To suppress wear of a fitting groove, and prevent uneven wear of the fitting groove.SOLUTION: A motor valve comprises: a valve body 12 including a valve chamber 13 communicating with a first flow path 14 and a second flow path 15; a valve element 18 that moves toward and away from a valve seat 16 formed in the valve chamber; an electric motor 31 that drives the valve element; a speed reduction mechanism 21 that reduces the rotational speed of the electric motor; an output shaft 22 that outputs the rotation reduced by the speed reduction mechanism; and a transmission mechanism 23 that converts the rotational motion of the output shaft into linear motion and transmits it to the valve element. The transmission mechanism is an electric valve that has a feed screw member 25 having a plate-shaped part 25c that is fitted into a slit-shaped fitting groove 22a formed in the output shaft in a vertically movable manner and a male screw part 25a formed on an outer surface, and a bearing member 24 having a female screw part 24a screwed to the male screw part, and a relief part 22b that communicates with the fitting groove and can receive a tip part of the plate-shaped part in a non-contact manner is provided at the back part of the fitting groove.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an electric valve, and more particularly to the structure of a power transmission part of a gear-type electric valve. [Background technology]

[0002] Electric valves, which use an electric motor such as a stepping motor to adjust the valve opening and control the flow rate of refrigerant, have traditionally been used in refrigeration cycle equipment with refrigerant circuits, such as air conditioners and refrigerators / freezers.

[0003] Another example of such a motor-operated valve is a gear-type motor-operated valve. Figures 5 to 7 show an example of a gear-type motor-operated valve. As shown in these figures, the motor-operated valve 41 includes a valve body 12 having an internal valve chamber 13 that communicates with a first flow path pipe 14 and a second flow path pipe 15, a valve element 18 that moves forward and backward relative to a valve seat 16 formed in the valve chamber 13, an electric motor 31 that drives the valve element 18, a speed reduction mechanism (paradox planetary gear reduction mechanism) 21 that reduces the rotation of the electric motor 31, an output shaft 22 that outputs the rotation reduced by the speed reduction mechanism 21, and a transmission mechanism 23 that converts the rotational motion of the output shaft 22 into linear motion and transmits it to the valve element 18.

[0004] The transmission mechanism 23 includes a feed screw member 25 having a plate-like portion 25c fitted into a slit-like fitting groove 22a formed in the output shaft 22 so as to be movable up and down, and a female threaded portion 24a formed on the inner surface of the lower part of the center hole of the bearing member 24. The feed screw member 25 has a male threaded portion 25a on its outer circumferential surface that screws into the female threaded portion 24a of the bearing member 24, and these male threaded portion 25a and female threaded portion 24a form a feed screw. Therefore, when the rotation of the output shaft 22 is transmitted to the feed screw member 25 via the fitting groove 22a and the plate-like portion 25c, the feed screw member 25 moves up and down while rotating. The up and down movement of the feed screw member 25 is then transmitted to the valve element 18 via a ball joint 26.

[0005] Furthermore, the following Patent Document 1 is a document that discloses such a motor-operated valve. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2017-9025 Summary of the Invention [Problem to be solved by the invention]

[0007] In the conventional motor-operated valve 41, as the valve body 18 moves up and down, the plate-shaped portion 25c of the feed screw member 25 slides up and down within the fitting groove (hereinafter sometimes simply referred to as "groove") 22a of the output shaft 22, and therefore the fitting groove 22a may wear out over time.

[0008] Here, the lower part (entrance part) of fitting groove 22a is always in contact with plate-shaped portion 25c, while the upper part (rear part) of fitting groove 22a comes into contact with plate-shaped portion 25c only when plate-shaped portion 25c is raised, so the lower part of the groove is worn deeply and the upper part of the groove is worn relatively less, resulting in uneven wear of fitting groove 22a. For this reason, in the past, there was a possibility that rattle would occur between output shaft 22 and feed screw member 25 (plate-shaped portion 25c) or that the coaxiality of output shaft 22 and feed screw member 25 would be reduced.

[0009] Furthermore, the portion of the plate-shaped portion 25c that is in contact with the corner 25d at the tip (top end) thereof is easily scraped and worn away by the corner 25d that is pushed upward within the fitting groove 22a when the feed screw member 25 ascends.

[0010] Therefore, an object of the present invention is to suppress wear of the fitting groove 22a and prevent uneven wear of the fitting groove 22a. [Means for solving the problem]

[0011] In order to solve the above problems and achieve the object, the electric valve of the present invention comprises a valve body having an internal valve chamber communicating with a first flow path and a second flow path, a valve element that moves toward and away from a valve seat formed in the valve chamber, an electric motor that drives the valve element, a speed reduction mechanism that reduces the rotation of the electric motor, an output shaft that outputs the rotation reduced by the speed reduction mechanism, and a transmission mechanism that converts the rotational motion of the output shaft into linear motion and transmits it to the valve element, wherein the transmission mechanism is an electric valve having a feed screw member that has a plate-shaped portion that is fitted into a slit-shaped fitting groove formed in the output shaft so as to be movable up and down and a male threaded portion formed on its outer surface, and a bearing member that screws into the male threaded portion, and a relief portion that communicates with the fitting groove and can receive the tip of the plate-shaped portion in a non-contact manner is provided at the back of the fitting groove.

[0012] In this application, the direction from the valve seat toward the valve disc is defined as "up," and the direction from the valve disc toward the valve seat is defined as "down," and based on these concepts of "up" and "down," terms related to up and down, such as "above," "below," "top," "bottom," "upper side," and "lower side," are used. However, because the motor-operated valve of this invention (as well as the embodiments described below) can be used in various orientations, "down" does not necessarily mean the direction of gravity and "up" does not necessarily mean the direction opposite to gravity.

[0013] The motor-operated valve of the present invention is a gear-type flow control valve for controlling the flow rate of a fluid such as a refrigerant, and, like the conventional motor-operated valve, includes a feed screw member and a bearing member as a transmission mechanism for transmitting the driving force of the electric motor to the valve element. When the rotation of the output shaft is transmitted to the feed screw member via the engagement groove and the plate-shaped portion, the feed screw member moves up and down due to the action of the feed screw, which is composed of a male threaded portion formed on the outer surface of the feed screw member and a female threaded portion provided on the bearing member. The up and down movement of the feed screw member is then transmitted to the valve element, which moves the valve element up and down. This changes the distance between the valve element and the valve seat, thereby changing the flow rate of the fluid.

[0014] On the other hand, in the motor-operated valve according to the present invention, a relief portion is provided at the back (upper portion) of the fitting groove of the output shaft. More specifically, the fitting groove is on the lower side and the relief portion is on the upper side, and the fitting groove and the relief portion are formed on the output shaft so that they (the fitting groove and the relief portion) are connected to each other and aligned vertically.

[0015] The relief portion prevents the tip (upper end) corner of the plate-shaped portion from contacting the inner surface of the fitting groove (moving up and down while in contact), and also prevents (or minimizes) the contact state between the fitting groove and the plate-shaped portion in the vertical direction from changing with the opening and closing operation of the valve (i.e., the up and down movement of the feed screw member), thereby preventing uneven wear of the fitting groove in the vertical direction.

[0016] More specifically, by providing a relief portion at the top of the fitting groove, the portion of the fitting groove that the plate-shaped portion contacts and does not contact as the plate-shaped portion moves up and down is reduced, thereby reducing the degree of uneven wear of the fitting groove. In particular, in a preferred embodiment of the present invention, the leading end (upper end or upper surface) of the plate-shaped portion is positioned within the relief portion when the valve is closed (i.e., when the plate-shaped portion is in the lowest position). According to this embodiment, the fitting groove is always in contact with the plate-shaped portion along its entire vertical length, and the contact state between the fitting groove and the plate-shaped portion in the vertical direction does not change with the opening and closing operation of the valve (up and down movement of the feed screw member). This prevents uneven wear of the fitting groove in the vertical direction. Furthermore, according to this embodiment, the leading edge of the plate-shaped portion, which is likely to wear the fitting groove, is always located within the relief portion and does not come into contact with the fitting groove, thereby suppressing wear of the fitting groove.

[0017] Furthermore, in the conventional electric valve, the contact area of ​​the feed screw member with the fitting groove increases as the feed screw member rises, resulting in increased sliding resistance. However, according to the preferred embodiment described above, the contact area of ​​the plate-shaped portion with the fitting groove does not change depending on the vertical position of the feed screw member, making it possible to maintain a constant sliding resistance of the feed screw member. [Effects of the Invention]

[0018] According to the present invention, wear of the fitting groove can be suppressed, and uneven wear of the fitting groove can be prevented.

[0019] Other objects, features, and advantages of the present invention will become apparent from the following detailed description of the preferred embodiments of the present invention, which is given with reference to the accompanying drawings. In the drawings, the same reference numerals indicate the same or corresponding parts. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 is a vertical cross-sectional view showing a motor-operated valve (in a closed state) according to one embodiment of the present invention. [Figure 2] FIG. 2 is a vertical cross-sectional view showing the motor-operated valve (fully open state) according to the embodiment. [Figure 3] FIG. 3 is a vertical cross-sectional view showing the output shaft and the feed screw member of the motor-operated valve according to the embodiment in a valve-closed state. [Figure 4] FIG. 4 is a vertical cross-sectional view showing the output shaft and the feed screw member of the motor-operated valve according to the embodiment in an open (fully open) state. [Figure 5] FIG. 5 is a vertical cross-sectional view showing an example of a conventional motor-operated valve (in a closed state). [Figure 6] FIG. 6 is a vertical cross-sectional view showing the output shaft and the feed screw member of the conventional motor-operated valve in a closed state. [Figure 7] FIG. 7 is a vertical cross-sectional view showing the output shaft and the feed screw member of the conventional motor-operated valve in an open (fully open) state. DETAILED DESCRIPTION OF THE INVENTION

[0021] An electric valve according to one embodiment of the present invention will be described with reference to Figures 1 to 4. Two-dimensional coordinates representing the up-down and left-right directions, which are orthogonal to each other, are appropriately displayed in each figure, and the following description will be based on these directions. Furthermore, although the terms "vertical" and "horizontal" are sometimes used, the vertical direction coincides with the up-down direction, and the direction orthogonal to the vertical direction is the horizontal direction, which includes the left-right direction.

[0022] As shown in Figures 1 to 4, an electric valve 11 according to one embodiment of the present invention is an electric valve suitable for use in adjusting the flow rate of a refrigerant in a refrigeration cycle device such as a heat pump type heating and cooling system, and is equipped with a valve body 12 having a valve chamber 13 and a valve seat 16 therein, a valve element 18 that is movable back and forth (up and down) relative to the valve seat 16, an electric motor 31 that drives the valve element 18, a speed reduction mechanism 21 that reduces the rotation of the electric motor 31 (a rotor 33 described later), a transmission mechanism 23 that converts the rotation reduced by the speed reduction mechanism 21 into linear motion and transmits it to the valve element 18, and a can (sealed container) 20 that forms an airtight space above the valve body 12.

[0023] The valve body 12 has a main body portion 12a that forms the valve chamber 13 and a cylindrical connection portion 12b that extends upward from the upper end of the main body portion 12a and allows connection to an electric motor 31 (can 20). The valve seat 16 is formed at the upper end of an orifice 17 that vertically penetrates the bottom surface of the main body portion 12a. A first flow path pipe 14 (corresponding to the first flow path of the present invention) is connected to the bottom surface of the main body portion 12a so as to communicate with the valve chamber 13 via the orifice 17. A second flow path pipe 15 (corresponding to the second flow path of the present invention) is connected to the side surface of the main body portion 12a so as to communicate with the valve chamber 13. In this embodiment, the first flow path pipe 14 is used as a refrigerant inlet path and the second flow path pipe 15 is used as a refrigerant outlet path. However, it is also possible to use the second flow path pipe 15 as the inlet path and the first flow path pipe 14 as the outlet path.

[0024] The connecting portion 12b has an outer diameter smaller than that of the main body portion 12a. Therefore, a step 12c is formed on the outer peripheral surface of the valve body 12 at the boundary between the main body portion 12a and the connecting portion 12b. The lower end of the can 20 is joined (welded) to this step 12c via a ring-shaped base plate 19, integrating the can 20 and the valve body 12. The can 20 is a cylindrical member with no bottom and a lid (the bottom is open and the top is closed) formed by press-forming a metal plate (e.g., a stainless steel plate).

[0025] In this embodiment, the electric motor 31 that drives the valve element 18 is configured by a stepping motor. This stepping motor 31 is made up of a stator 32 installed on the outside (outer periphery) of the can 20 and a rotor 33 rotatably installed on the inside (inner periphery) of the can 20.

[0026] The stator 32 includes a yoke 34, a coil 36 formed by winding a wire around a bobbin 35, and a resin mold cover 37 that covers the yoke 34 and the coil 36.

[0027] On the other hand, the rotor 33 is rotatably supported by a round rod-shaped support shaft member 38 that extends vertically through the center of the can 20 along the central axis A. The support shaft member 38 has a lower end that is relatively rotatably fitted into the upper part of an output shaft 22 (described later) that outputs the rotation of the rotor 33, and an upper end that is supported by a support member 39 that is arranged inside the upper part of the can 20.

[0028] A paradox planetary gear mechanism having a high reduction ratio and advantageous for miniaturization is provided inside the rotor 33 as the reduction mechanism 21. The rotation of the rotor 33 is reduced in speed by the reduction mechanism 21 and is transmitted to and output from the output shaft 22 provided at the center of the underside of the rotor 33.

[0029] A cylindrical bearing member 24 is disposed below the rotor 33, and this bearing member 24 rotatably supports the output shaft 22. The bearing member 24 is fitted into and fixed in the connecting portion 12b of the valve body 12.

[0030] A fitting hole 24b is formed in the center of the upper surface of the bearing member 24, and the output shaft 22 is rotatably inserted into this fitting hole 24b. Meanwhile, a female thread portion 24a is formed in the lower center portion of the bearing member 24, and a male thread portion 25a formed on the outer peripheral surface of the feed screw member 25 is screwed into this female thread portion 24a. The bearing member 24 (female thread portion 24a) and the feed screw member 25 (male thread portion 25a) form a feed screw mechanism, and constitute the transmission mechanism 23 that converts the rotational motion supplied from the stepping motor 31 via the speed reduction mechanism 21 into linear motion in the vertical direction and transmits it to the valve element 18.

[0031] That is, the feed screw member 25 has a cylindrical portion 25b with the male thread portion 25a formed on its outer surface and a flat screwdriver-shaped plate-like portion 25c that rises vertically upward from the upper surface of the cylindrical portion 25b. The plate-like portion 25c is fitted into a slit-like fitting groove 22a provided at the lower end of the output shaft 22 so as to be slidable in the vertical direction. Here, the rotor 33 and the output shaft 22 rotate without moving up and down at a fixed position in the vertical direction, and this rotational motion is transmitted to the feed screw member 25 via the fitting groove 22a and the plate-like portion 25c. Therefore, when the rotor 33 rotates, the plate-like portion 25c provided on the feed screw member 25 slides up and down within the fitting groove 22a of the output shaft 22. Therefore, even though the output shaft 22 does not move up and down, the feed screw member 25 moves linearly up and down due to the feed screw mechanism.

[0032] Furthermore, an escape portion 22b that communicates with the fitting groove 22a and receives the tip end of the plate-like portion 25c in a non-contact state is provided at the upper end (rear portion) of the fitting groove 22a. This escape portion 22b is a cylindrical space (with a circular cross section) that extends in the front-to-rear direction (the direction perpendicular to the paper surface of FIGS. 1 to 4) so ​​as to communicate with the fitting groove 22a at the upper end of the fitting groove 22a, has a diameter larger than the groove width (width dimension in the left-to-right direction) of the fitting groove 22a, and penetrates the output shaft 22 horizontally. The escape portion 22b functions to keep the contact area between the plate-like portion 25c and the output shaft 22 (the inner surface of the fitting groove 22a) constant as follows.

[0033] When the feed screw member 25 is in the lowest position (see FIGS. 1 and 3 ) in the closed valve state, the upper surface of the plate-shaped portion 25c is located inside (at the bottom of) the relief portion 22b. On the other hand, when the valve is open, the feed screw member 25 rises, and the upper portion of the plate-shaped portion 25c moves upward so that it is inserted into the relief portion 22b. The upper end of the plate-shaped portion 25c inserted into the relief portion 22b does not contact any other components, including the output shaft 22 (the engagement groove 22a). On the other hand, the engagement groove 22a is always in contact with the plate-shaped portion 25c over its entire length in the vertical direction, and the contact state between the engagement groove 22a and the plate-shaped portion 25c in the vertical direction does not change with the opening and closing operation of the motor-operated valve 11 (the up and down movement of the feed screw member 25). This prevents uneven wear of the engagement groove 22a in the vertical direction.

[0034] In addition, the upper end corners 25d of the plate-like portion 25c, which are likely to wear out the fitting groove 22a, are always located inside the relief portion 22b and do not come into contact with the fitting groove 22a, so that wear of the fitting groove 22a can be suppressed compared to conventional methods. Furthermore, because the contact area of ​​the plate-like portion 25c with the fitting groove 22a does not change depending on the vertical position of the feed screw member 25, the sliding resistance of the feed screw member 25 can be kept constant, and stable opening and closing operations of the motor-operated valve 11 (vertical movement of the feed screw member 25) can be achieved.

[0035] Furthermore, grease is generally applied between the fitting groove 22a and the plate-like portion 25c to reduce sliding resistance, and the relief portion 22b can also function as a grease reservoir for storing the grease. Furthermore, wear powder may be generated over time due to the sliding of the plate-like portion 25c, but by storing and retaining this inside the relief portion 22b, the provision of the relief portion 22b makes it possible to reduce the possibility of wear powder getting caught between the male thread portion 25a and the female thread portion 24a or between the valve disc 18 and the valve seat 16, for example, which could adversely affect these operations or cause valve leakage.

[0036] The vertical linear motion of the feed screw member 25 described above is transmitted to the valve element 18 via a ball joint 26 consisting of a ball 26a and a ball seat 26b. By using the ball joint 26 in this manner, only the vertical linear motion of the feed screw member 25 is transmitted to the valve element 18 without transmitting the rotational motion of the feed screw member 25.

[0037] The valve element 18 is a cylindrical member having a needle-shaped (inverted cone-shaped) tip at its lower end that comes into contact with (abuts against) the valve seat 16, and a flange portion 18a that projects outward horizontally at its upper end. A fitting hole 18b is formed in the upper surface of the valve element 18, and the ball seat 26b is fitted into this fitting hole 18b.

[0038] Furthermore, a stepped cylindrical valve element guide member 27 is provided inside the valve chamber 13. This valve element guide member 27 comprises a guide portion 27a with small diameters (inner and outer diameters) formed at its lower end, a ring-shaped flange portion 27c that extends horizontally outward from its upper end, and a large-diameter portion 27b with large diameters (inner and outer diameters) formed in its middle portion (between the guide portion 27a and the flange portion 27c). The guide portion 27a supports the valve element 18 so that it can slide up and down. The flange portion 27c is positioned so as to rest on a step portion 12d formed at the lower end of the inner circumferential surface of the connecting portion 12b of the valve body 12. The flange portion 27c is sandwiched between the step portion 12d and the bearing member 24, thereby preventing the valve element guide member 27 from shifting up and down. Furthermore, a step portion 27d is formed on the inner circumferential surface of the valve element guide member 27 between the large-diameter portion 27b and the guide portion 27a.

[0039] A compression coil spring 28 is provided inside the large diameter portion 27b, more specifically, in the gap between the outer circumferential surface of the valve element 18 and the inner circumferential surface of the large diameter portion 27b. This compression coil spring 28 is disposed in a compressed state between the flange portion 18a of the valve element 18 and the step portion 27d of the valve element guide member 27 to urge the valve element 18 upward (in the valve-opening direction), and by pressing the valve element 18 against the feed screw member 25 via the flange portion 18a of the valve element 18 and the ball joint 26, the valve element 18, the ball joint 26, and the feed screw member 25 are integrally held together in the up-and-down direction, and the urging force of the compression coil spring 28 is applied to the valve element 18 in addition to the driving force of the electric motor 31 during the valve-opening operation, thereby more reliably performing the valve-opening operation.

[0040] In this embodiment, the central axes A of the valve body 12 (main body portion 12a and connection portion 12b), valve seat 16, orifice 17, valve element 18, ball joint 26, bearing member 24, can 20 and support shaft member 38, and the central axes (rotation axes) A ​​of the rotor 33, output shaft 22 and feed screw member 25 are aligned with one another.

[0041] The operation of the motor-operated valve 11 according to this embodiment will be described as follows.

[0042] When current is supplied to the stator 32 (coil 36) so that the rotor 33 rotates in one direction from the closed valve state shown in Figure 1, the rotation of the rotor 33 is decelerated by the speed reduction mechanism 21 and then converted into linear motion by the transmission mechanism 23, causing the feed screw member 25 to be pulled upward. Accordingly, the valve element 18, which is pressed against the lower surface of the feed screw member 25 via the ball joint 26 by the biasing force of the compression coil spring 28, is pulled upward, separating the valve element 18 from the valve seat 16. This results in an open valve state in which the refrigerant that has flowed in through the first flow tube 14 passes through the valve chamber 13 and flows out of the second flow tube 15 (see arrow F in Figure 2). The amount of refrigerant passing through (refrigerant flow rate) in this open valve state can be adjusted by the amount of rotation of the rotor 33 (the distance between the valve element 18 and the valve seat 16).

[0043] On the other hand, when current is supplied to the stator 32 (coil 36) so that the rotor 33 rotates in the opposite direction from the open valve state, the rotation of the rotor 33 is converted into linear motion by the transmission mechanism 23, and the feed screw member 25 moves downward. As this downward movement occurs, the valve element 18 also moves downward, and when the valve element 18 seats on the valve seat 16, the flow path between the first flow path pipe 14 and the second flow path pipe 15 is blocked, and the valve is placed in a closed state (see FIG. 1).

[0044] Although the embodiments of the present invention have been described above, the present invention is not limited to these, and it will be apparent to those skilled in the art that various modifications can be made within the scope of the claims.

[0045] For example, although the relief portion 22b has a circular cross-sectional shape in the above embodiment, it may have any cross-sectional shape as long as it can accommodate the upper end of the plate-shaped portion 25c in a non-contact state (without contacting the upper end of the plate-shaped portion 25c). Also, although the above embodiment includes a paradox planetary gear mechanism as the reduction mechanism 21, it is also possible to adopt a planetary gear mechanism other than a paradox planetary gear mechanism or another reduction mechanism. [Explanation of symbols]

[0046] A central axis (axis of rotation) F Refrigerant flow 11,41 Motor-operated valve 12 Valve body 12a Main body 12b Connection 12c Step on outer surface of valve body 12d Step 13 Valve chamber 14 First flow pipe 15 Second flow pipe 16 Valve seat 17 Orifice 18 Valve body 18a Flange part of valve body 18b Mating hole 19 Base Plate 20 Can (sealed container) 21 Reduction mechanism (paradoxical planetary gear mechanism) 22 Output shaft 22a Fitting groove 22b Relief 23 Transmission mechanism (feed screw mechanism) 24 Bearing material 24a female thread 24b Insertion hole 25 Lead screw member 25a male thread 25b Cylindrical part 25c Plate-shaped part 25d Upper end (tip) corner of plate-shaped part 26 Ball joint 26a Ball 26b Ball seat 27 Valve body guide member 27a Guide part 27b Large diameter section 27c Flange portion of valve body guide member 27d Step of valve body guide member 28 Compression coil spring 31 Electric motor (stepping motor) 32 Stator 33 Rotor 34 York 35 bobbin 36 coils 37 Resin mold cover 38 Support shaft member 39 Support member

Claims

1. a valve body having a valve chamber therein that communicates with the first flow path and the second flow path; a valve body that moves toward and away from a valve seat formed in the valve chamber; an electric motor that drives the valve body; a speed reduction mechanism that reduces the speed of rotation of the electric motor; an output shaft that outputs rotation reduced by the reduction mechanism; a transmission mechanism that converts the rotational motion of the output shaft into linear motion and transmits the linear motion to the valve body; Equipped with The transmission mechanism includes: a feed screw member having a plate-like portion fitted into a slit-like fitting groove formed in the output shaft so as to be movable up and down, and a male screw portion formed on an outer peripheral surface; a bearing member having a female thread portion that screws into the male thread portion; have A motor-operated valve, A relief portion that communicates with the fitting groove and can receive the tip end of the plate-like portion in a non-contact state is provided at the back of the fitting groove. A motor-operated valve characterized by:

2. The tip of the plate-shaped portion is disposed inside the relief portion in a closed valve state. The motor-operated valve according to claim 1 .

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