JP7549564B2 - Valve mechanism - Google Patents

Description

The present invention relates to a valve device.

Conventionally, a motor-operated valve has been proposed as a valve device in which a porous body made of foam metal is arranged along the inner wall surface of the valve body (see, for example, Patent Document 1). In the motor-operated valve described in Patent Document 1, the porous body is cut out in a portion corresponding to the opening where the conduit joint is attached, thereby reducing abnormal noise.

JP 2018-087642 A

However, the motor-operated valve described in Patent Document 1 requires space to place the porous body, which has the disadvantage that the entire motor-operated valve tends to become large. On the other hand, simply making the valve body smaller narrows the flow path regardless of whether the porous body is present or not, making the fluid flow uneven. When fluid with an uneven flow passes through the valve port, it can cause noise. In other words, it is difficult to achieve both the miniaturization of the entire device and the suppression of noise.

The object of the present invention is to provide a valve device that can suppress noise while preventing the device from becoming too large overall.

The valve device of the present invention is a valve device comprising a cylindrical valve housing with an opening formed on the side, a valve body provided in a valve chamber inside the valve housing, a valve port to which the valve body approaches or moves away, and a cylindrical coupling member that is inserted into the opening to connect to the valve housing, and is characterized in that the end face of the coupling member that is inserted into the valve housing is in contact with a virtual inner circumferential surface that is a virtual extension of the inner circumferential surface of the valve housing to the opening or is disposed outside the virtual inner circumferential surface, and in a flow path in which a fluid passes through the valve chamber between the coupling member and the valve port, the passable area in a cross section that includes the central axes of both the valve housing and the coupling member, and the smallest passable area among cross sections that are perpendicular to the central axis of the valve housing and pass through the valve body are larger than the inner cross-sectional area of the coupling member.

According to the present invention as described above, the end face of the coupling member is in contact with the imaginary inner peripheral surface of the valve housing or is disposed outside the imaginary inner peripheral surface, so that the coupling member does not protrude into the valve housing. This makes it possible to suppress unevenness in the flow of the fluid in the valve chamber when the fluid flows into the valve chamber from the coupling member, and to suppress flow velocity differences and pressure differences. This makes it possible to suppress noise caused by vibration of the valve device and passing sounds when the fluid passes through the valve port. In addition, the passable area in a cross section including the central axes of both the valve housing and the coupling member, and the minimum passable area among the cross sections perpendicular to the central axis of the valve housing and passing through the valve body are larger than the inner cross-sectional area of the coupling member, so that the fluid flowing into the valve chamber from the coupling member is not throttled, the flow of the fluid can be stabilized, and noise can be suppressed. Furthermore, since the coupling member does not protrude into the valve housing, it is easy to increase the two types of passable cross-sectional areas, and the overall size of the device can be suppressed.

In this case, the valve device of the present invention preferably further comprises a guide member for guiding the valve body, and in the flow path through which the fluid passes through the valve chamber between the coupling member and the valve port, the smallest passable area among the cross sections passing through the valve body or the guide member that are perpendicular to the central axis of the valve housing within the range of a virtual extension of the coupling member into the valve chamber is preferably larger than the inner cross-sectional area of the coupling member. With this configuration, it is easier to prevent the fluid that has flowed into the valve chamber from being throttled.

In this case, in the valve device of the present invention, it is preferable that the inner peripheral surface and the virtual inner peripheral surface of the valve housing extend along a cylindrical surface. With this configuration, the fluid that flows into the valve chamber from the coupling member can flow smoothly along the inner peripheral surface of the valve housing, further reducing noise. In this case, it is more preferable that no openings (e.g., openings for sound-deadening members) are formed on the side surface of the valve housing other than the opening for the coupling member.

In addition, in the valve device of the present invention, it is preferable that the inner diameter of the coupling member is larger than the maximum outer diameter of the valve body. With this configuration, the flow of fluid that has flowed from the coupling member into the valve chamber is less likely to be blocked by the valve body, further reducing noise.

In addition, in the valve device of the present invention, it is preferable that the end face of the coupling member that is inserted into the valve housing extends along a plane perpendicular to the central axis of the coupling member, and that the entire end face is located inside the outer circumferential surface of the valve housing. With this configuration, when assembling the coupling member to the valve housing, there is no need to adjust the orientation of the coupling member (the rotation angle around the axial direction), improving assembly. That is, in a configuration in which the end face of the coupling member has a shape that follows the periphery of the opening and therefore does not protrude into the valve housing, it is necessary to adjust the orientation of the coupling member, whereas such adjustment is not necessary when the end face is along a plane perpendicular to the central axis.

In addition, in the valve device of the present invention, it is preferable that the opening is formed with an insertable portion into which the coupling member can be inserted, and a restricting portion that restricts the insertion of the coupling member by protruding toward the inner diameter side on the inside of the insertable portion. With this configuration, it is possible to restrict over-insertion of the coupling member and to set the insertion depth to a predetermined depth. This makes it easy to prevent the coupling member from protruding into the valve housing.

In addition, in the valve device of the present invention, it is preferable that the minimum inner diameter of the regulating portion is equal to or greater than the inner diameter of the coupling member. Furthermore, in the valve device of the present invention, it is more preferable that the protruding dimension of the regulating portion protruding from the insertable portion toward the inner diameter side is equal to or less than 50% of the thickness of the coupling member. With this configuration, when fluid flows from the coupling member into the valve chamber, the flow is less likely to be blocked by the regulating portion, and noise can be further reduced.

The valve device of the present invention can prevent the overall size of the valve device from increasing and also suppress noise.

1 is a cross-sectional view showing a valve device according to an embodiment of the present invention. 4 is a cross-sectional view showing a connection portion between a valve housing and a coupling member in the valve device. FIG. 4 is a cross-sectional view showing a fluid passage portion in the valve device. FIG. 4 is a cross-sectional view showing a fluid passage portion in the valve device. FIG. 5 is a cross-sectional view showing a connection portion between a valve housing and a coupling member in a valve device according to a first modified example. FIG. FIG. 11 is a cross-sectional view showing a fluid passage portion in a valve device according to a second modified example. FIG. 11 is a cross-sectional view showing a fluid passage portion in a valve device according to a third modified example. FIG. 11 is a cross-sectional view showing a fluid passage portion in a valve device according to a third modified example.

An embodiment of the present invention will be described with reference to the drawings. The motor-operated valve 1 of this embodiment is a valve device used in the refrigeration cycle system of an air conditioner such as a packaged air conditioner or a room air conditioner, and includes a valve housing 2, a valve body 3, a valve holder 4, a support member 5, and a stepping motor 6.

The valve housing 2 is formed in a cylindrical shape with an open top, and houses the valve body 3 and the valve holder 4 in the valve chamber 2A inside the valve housing 2. The valve housing 2 has a cylindrical side portion 27 and a bottom surface portion 28 provided at one end of the side portion 27 (the lower end in FIG. 1). The cylindrical side portion 27 has an outer surface 271 and an inner surface 272, and the inner surface 272 has an inner peripheral surface S1. The inner surface 272 has a shape with an expanded diameter at the top, but the inner peripheral surface S1 refers to the part that is not expanded, and in particular refers to the periphery of the area where the opening 21 is formed. In addition, the inner peripheral surface S1 does not include the opening 21 itself. In the following, the axial direction of the valve housing 2 is the Z direction, and the two directions perpendicular to the Z direction are the X direction and the Y direction, respectively. In addition, in the following, the top and bottom in the Z direction are based on FIG. 1, with the upper side being the valve open side and the lower side being the valve closed side. An opening 21 is formed in the side surface portion 27 of the valve housing 2, through which the coupling member 10 communicating with the valve chamber 2A is inserted, and a cylindrical opening 22 is formed in the lower end portion (bottom surface portion 28). An end portion of the coupling member 11 extending in the Z direction is inserted and connected to the cylindrical opening 22, and a valve seat portion 23 is integrally formed. The coupling member 11 communicates with the valve port 24 of the valve seat portion 23. No openings other than the opening 21 are formed in the side surface portion 27.

The valve body 3 is provided at the lower end of the valve holder 4; that is, it is fitted into the valve holder 4, welded and fixed, and suspended from the valve holder 4. The valve body 3 extends downward from the valve holder 4 and has a needle valve 31 at its tip. The needle valve 31 moves toward or away from the periphery 25 of the valve port 24 (described later) of the valve seat portion 24. In this embodiment, the needle valve 31 can abut against the periphery 25, and the portion of the periphery 25 where the needle valve 31 abuts becomes the seal portion.

The valve holder 4 is formed in a cylindrical shape extending along the Z direction, and its upper end is engaged with the lower end of the rotor shaft 61 of the stepping motor 6, which will be described later. That is, the valve holder 4 is suspended by the rotor shaft 61 and is rotatable relative to the rotor shaft 61. A compression coil spring 41 is provided in the valve holder 4, and a downward load is applied to the valve body main body 3. The valve body 20 is formed by the valve body main body 3 and the valve holder 4 as described above. That is, the "valve body" includes the valve body main body that moves toward and away from the periphery of the valve port, as well as a member that moves integrally with the valve body, and may include members other than the valve holder. Also, the "valve body" may include at least the valve body main body, and may not include a valve holder, a compression coil spring, etc.

The support member 5 is fixed to the valve housing 2 at a flange portion 51 so as to close the upper opening of the valve housing 2. The support member 5 is formed with a guide recess 52 that accommodates the valve holder 4 and guides it in the Z direction, a female thread portion 53 into which the rotor shaft 61 screws, and a communication hole 54 that communicates between the guide recess 52 and a space within a case 62 (described later) of the stepping motor 6. The support member 5 functions as a guide member by having the guide recess 52 that guides the valve holder 4 of the valve body 20.

The stepping motor 6 is composed of a rotor shaft 61, a case 62, a magnet rotor 63, and a stator coil 64. A magnet rotor 63, whose outer periphery is magnetized with multiple poles, is rotatably provided within the case 62, and the rotor shaft 61 is fixed to the magnet rotor 63. Furthermore, the case 62 is fixed to the valve housing 2 so as to close the upper opening of the valve housing 2. The stator coil 64 is disposed on the outer periphery of the case 62. When a pulse signal is given to the stator coil 64, the stepping motor 6 rotates the magnet rotor 63 according to the number of pulses.

The rotor shaft 61 has a male thread 611 formed on its outer periphery, which screws into the female thread 53 of the support member 5. When the stepping motor 6 is driven, the magnet rotor 63 and the rotor shaft 61 rotate, and the rotor shaft 61 moves in the Z direction by a screw feed mechanism formed by the male thread 611 and the female thread 53. As a result, the valve holder 4 suspended from the rotor shaft 61 moves in the Z direction while being guided by the guide recess 52 of the support member 5, and the needle valve 31 of the valve body 3 abuts against or separates from the periphery 25 of the valve port 24 (seated or unseated), opening and closing the valve port 24. Note that the needle valve 31 may be configured not to abut against the periphery 25 of the valve port 24 when it comes closest to the periphery 25 of the valve port 24. The opening degree of the valve port 24 is controlled according to the position (lift amount) of the valve body 3 in the Z direction, and the flow rate of the fluid flowing through the valve port 24 is controlled.

Here, the detailed relationship between the opening 21 formed on the side surface of the valve housing 2 and the coupling member 10 inserted into this opening 21 will be described with reference to FIG. 2. FIG. 1 shows a cross section including the central axes L1, L2 of both the valve housing 2 and the coupling member 10, and FIG. 2 shows a cross section perpendicular to the central axis L1 of the valve housing 2 (a cross section taken along line Z2-Z2 in FIG. 1). The coupling member 10 is formed in a cylindrical shape extending along the X direction (i.e., the central axis L2 is along the X direction), and the opening 21 is formed in a circular shape when viewed from the X direction in correspondence with the outer circumferential surface of the coupling member 10. The outer diameter of the coupling member 10 is equal to or slightly smaller than the inner diameter of the opening 21.

The end face 101 of the coupling member 10 on the side that is inserted into the valve housing 2 is in contact with the imaginary inner circumferential surface S2 that is a virtual extension of the inner circumferential surface S1 of the valve housing 2 to the opening 21, or is located outside the imaginary inner circumferential surface S2. That is, the imaginary inner circumferential surface S2 is arc-shaped in a cross section along the XY plane as shown in FIG. 2, and the center part of the imaginary inner circumferential surface S2 is in contact with the end face 101, or the end face 101 is located outside the center part (on the right side in FIGS. 1 and 2). As a result, the coupling member 10 does not protrude into the valve chamber 2A in the valve housing 2. Furthermore, the entire end face 101 is located inside the outer circumferential surface of the valve housing 2. That is, the outer circumferential edge of the end face 101 is located within the opening 21. In addition, in the cross-sectional view of FIG. 2, the imaginary inner circumferential surface S2 is shown by a dashed line, but the inner edge 211 in the X direction of the opening 21 exists behind this.

The end face 101 of the coupling member 10 extends along the YZ plane and has a shape that has rotational symmetry around the central axis L2 (i.e., when the coupling member 10 is rotated by any angle around the central axis L2, it overlaps with its original shape). In contrast, since the opening 21 is formed on the side surface of the cylindrical valve housing 2, the imaginary inner circumferential surface S2 has a three-dimensional shape that follows a cylindrical curved surface that extends in the Z direction (axis L1 direction) like the inner circumferential surface S1.

Next, the area of the flow path when the fluid flows from the coupling member 10 to the valve chamber 2A will be described. In the flow path through which the fluid passes through the valve chamber 2A between the coupling member 10 and the valve port 24, a passage portion A1 in a cross section including the central axes L1, L2 of both the valve housing 2 and the coupling member 10 is shown by hatching in FIG. 3. In this embodiment, the upper end of this passage portion A1 is, for example, an extension line obtained by virtually extending the upper end of the outer circumferential surface of the coupling member 10 along the X direction. When the fluid flows from the coupling member 10 to the valve chamber 2A, the fluid tries to flow in a region obtained by virtually extending the inner circumferential surface of the coupling member 10 into the valve chamber 2A. At this time, a part of the fluid actually flows outside this extended region, so in this embodiment, the passage portion A1 is defined using an extension line obtained by extending the outer circumferential surface of the coupling member 10 including the thickness of the coupling member 10. Depending on the thickness of the coupling member, such as the speed and flow rate of the fluid, an extension line extending from the center of the coupling member in the thickness direction may be used, or an extension line extending from the inner circumferential surface may be used.

The upper surface of the bottom portion 28 of the valve housing 2 has an annular surface 281 extending along the XY plane, and a truncated cone surface 282 that is continuous with the inside of the annular surface 281 and extends upward as it approaches the periphery 25 of the valve port 24, and has a shape that rises at the center. That is, a recess is formed around the periphery 25 of the valve port 24, and the annular surface 281, which is the bottom surface of this recess, is located below the lower end of the coupling member 10. The passing portion A1 also includes this recess. Furthermore, the passing portion A1 refers to the space inside the valve housing 2 and outside the valve body 3, the valve holder 4, and the support member 5. The passable area of the passing portion A1 is larger than the inner cross-sectional area of the coupling member 10.

In the flow path through the valve chamber 2A between the coupling member 10 and the valve port 24, the cross section (cross section along the line Z2-Z2) that is perpendicular to the central axis L1 of the valve housing 2 and passes through the valve body 20 and has the smallest fluid passable area, and the passing section A2 are shown in hatching in FIG. 4. In this embodiment, FIG. 4 shows a cross section that passes through the valve holder 4. In this embodiment, the maximum outer diameter of the valve holder 4 is equal to the inner diameter of the guide recess 52. Furthermore, the passing section A2 refers to the space inside the valve housing 2 and outside the valve holder 4. The passing area of the passing section A2 is larger than the inner cross-sectional area of the coupling member 10. Furthermore, the inner diameter of the coupling member 10 is larger than the maximum outer diameter of the valve body 20 (i.e., the outer diameter of the valve holder 4).

According to the present embodiment described above, since the coupling member 10 does not protrude into the valve chamber 2A, when the fluid flows from the coupling member 10 into the valve chamber 2A, the flow of the fluid in the valve chamber 2A is prevented from becoming uneven, and the flow velocity difference and pressure difference can be suppressed. Therefore, noise caused by vibration of the motor-operated valve 1 and the passing sound of the fluid can be suppressed. In addition, since the area of the passing parts A1 and A2 is larger than the inner cross-sectional area of the coupling member 10, the fluid that flows from the coupling member 10 into the valve chamber 2A is not throttled, the flow of the fluid can be stabilized, and noise can be suppressed. Furthermore, since the coupling member 10 does not protrude into the valve chamber 2A, it is easy to increase the passing cross-sectional areas A1 and A2, and the size of the entire device can be suppressed.

In addition, because the inner circumferential surface and the imaginary inner circumferential surface S2 of the valve housing 2 extend along a cylindrical surface, the fluid that flows from the coupling member 10 into the valve chamber 2A can flow smoothly along the inner circumferential surface of the valve housing 2, further reducing noise. Furthermore, because the side portion 27 has no openings other than the opening 21, the fluid can flow more smoothly along the inner circumferential surface of the valve housing 2.

In addition, because the inner diameter of the coupling member 10 is larger than the maximum outer diameter of the valve body 20, the flow of fluid that flows from the coupling member 10 into the valve chamber 2A is less likely to be blocked by the valve body main body 3, further reducing noise.

In addition, because the end face 101 of the coupling member 10 extends along the YZ plane, there is no need to adjust the orientation of the coupling member 10 (the rotation angle around the X direction) when assembling the coupling member 10 to the valve housing 2, improving ease of assembly.

The present invention is not limited to the above-described embodiment, and includes other configurations that can achieve the object of the present invention, and the following modifications are also included in the present invention. In the modifications described below, the same configurations as those in the above-described embodiment are denoted by the same reference numerals, and the description thereof is omitted. In the above-described embodiment, the inner diameter of the opening 21 is constant, and the coupling member 10 is simply inserted through the opening 21. However, as a first modification, as shown in FIG. 5, the opening 26 may be formed with an insertable portion 261 into which the coupling member 10 can be inserted, and a restricting portion 262 that protrudes toward the inner diameter side of the opening 26 on the inner side in the insertion direction from the insertable portion 261, thereby restricting the insertion of the coupling member 10.

In the first modified example, the inner diameter of the insertable portion 261 is equal to or slightly larger than the outer diameter of the coupling member 10, and the minimum inner diameter of the restricting portion 262 is smaller than the outer diameter of the coupling member 10. The step formed by the insertable portion 261 and the restricting portion 262 restricts over-insertion of the coupling member 10, and the insertion depth can be set to a predetermined depth, making it easy to prevent the coupling member 10 from protruding into the valve chamber 2A. The restricting portion 262 may be formed in a circular shape when viewed from the X direction, or may partially protrude inward in the circumferential direction.

In the first modified example, the minimum inner diameter of the restricting portion 262 is equal to or greater than the inner diameter of the coupling member 10. Furthermore, the protruding dimension L3 by which the restricting portion 262 protrudes from the insertable portion 261 toward the inner diameter side of the opening 26 is equal to or less than 50% of the thickness of the coupling member 10. This makes it difficult for the restricting portion 262 to block the flow of fluid from the coupling member 10 into the valve chamber 2A, further reducing noise.

In the first modified example, the minimum inner diameter of the restricting portion 262 is equal to or greater than the inner diameter of the coupling member 10, and the protruding dimension of the restricting portion 262 protruding from the insertable portion 261 toward the inner diameter side is equal to or less than 50% of the thickness of the coupling member 10, but the relationship of each dimension is not limited to this. For example, if the thickness of the coupling member is small, the protruding dimension may be greater than 50% of this thickness, and the minimum inner diameter of the restricting portion may be equal to or less than the inner diameter of the coupling member. By increasing the protruding dimension of the restricting portion, it becomes easier for the restricting portion to engage the coupling member and to restrict over-insertion.

In the above embodiment, the area of the passage A2, which is perpendicular to the central axis L1 of the valve housing 2 and passes through the valve body 20, and in which the area through which the fluid can pass is the smallest, is larger than the inner cross-sectional area of the coupling member 10. However, as such a passage, a cross-section that passes through other than the valve body and in which the area through which the fluid can pass may be adopted. For example, as shown in FIG. 1, in a flow path through which the fluid passes through the valve chamber 2A between the coupling member 10 and the valve port 24, the support member 5 is included in a range that is a virtual extension of the coupling member 10 (including the outer peripheral surface, inner peripheral surface, and central portion in the thickness direction of the coupling member) into the valve chamber 2A, and when the support member 5 has a larger outer diameter than the valve body 20, the passage may be defined based on the cross-section that passes through the support member 5. That is, as shown in FIG. 6 as a second modified example, the area of the passage A5 (the space outside the support member 5 and inside the valve housing) in the cross-section along the Z1-Z1 line in FIG. 1 may be larger than the inner cross-sectional area of the coupling member 10.

In addition, in the above embodiment, the inner diameter of the coupling member 10 is larger than the maximum outer diameter of the valve body 20, but the dimensions of the coupling member and the valve body can be set appropriately depending on the application of the valve device and the expected flow rate, etc., and the inner diameter of the coupling member may be equal to or smaller than the maximum outer diameter of the valve body.

In the above embodiment, the end surface 101 of the coupling member 10 extends along the YZ plane, but the end surface may extend along a curved surface. For example, the end surface of the coupling member may have a three-dimensional shape (shape along the imaginary inner peripheral surface S2) along the inner peripheral edge of the opening 21. With such a configuration, the area where the outer peripheral surface of the coupling member and the inner peripheral surface of the opening 21 face each other can be increased, and the connection structure can be stabilized. In addition, if the worker can grasp the orientation of the coupling member by, for example, marking the outer peripheral surface of the coupling member, the assembling can be ensured. In the above embodiment, the entire end surface 101 of the coupling member 10 is located inside the outer peripheral surface of the valve housing 2, but a part of the end surface of the coupling member may be located outside the outer peripheral surface of the valve housing.

In the above embodiment, the end face 101 of the coupling member 10 is located outside the virtual inner circumferential surface S2, and the coupling member 10 does not protrude into the valve chamber 2A. However, as a third modified example, as shown in Figs. 7 and 8, the end face 101 of the coupling member 10 may intersect the virtual inner circumferential surface S2, and the coupling member 10 may protrude slightly into the valve chamber 2A. In this case, the passing portion A3 shown in Fig. 7 and the passing portion A4 shown in Fig. 8 are areas inside the plane S3 along the end face 101. Even in this second modified example, the passing portions A3 and A4 are both larger than the inner cross-sectional area of the coupling member 10, and noise can be suppressed. Furthermore, if the end face 101 of the coupling member 10 protrudes to the extent that it intersects with the virtual inner circumferential surface S2, the area of the passing portions A3 and A4 can be easily increased, and the size of the entire device can be suppressed.

In addition, in the above embodiment, the motor-operated valve 1 is exemplified as the valve device, but the valve device may be one in which a coupling member is inserted into an opening in the side of a cylindrical valve housing, and the drive method and other structures are not particularly limited. For example, the valve device may be an electromagnetic valve that includes an attractor, a plunger, and an electromagnetic coil, and in which the plunger is driven by energizing or deenergizing the electromagnetic coil, causing a valve body provided on the plunger to approach or move away from a valve port.

The above describes the embodiments of the present invention in detail with reference to the drawings, but the specific configuration is not limited to these embodiments, and the present invention also includes design changes that do not deviate from the gist of the present invention.

1...valve device, 2...valve housing, 21, 26...opening, 24...valve port, 261...insertable portion, 262...regulating portion, 2A...valve chamber, 3...valve body, 5...support member (guide member), 10...joint member, 101...end face, 20...valve body, S1...inner surface, S2...virtual inner surface

Claims (10)

A valve device comprising: a cylindrical valve housing having an opening formed on a side surface; a valve element provided in a valve chamber inside the valve housing; a valve port to which the valve element approaches or moves away; a cylindrical coupling member connected to the valve housing by being inserted through the opening; a stepping motor; and a screw feed mechanism that converts rotational motion generated by the stepping motor to linearly move the valve element ,
the stepping motor includes a case fixed to the valve housing, a magnet rotor provided within the case, and a stator coil disposed on an outer periphery of the case,
an end surface of the coupling member that is inserted into the valve housing is in contact with a virtual inner circumferential surface that is a virtual extension of an inner circumferential surface of the valve housing to the opening, or is disposed outside the virtual inner circumferential surface,
a valve device characterized in that, in a flow path in which a fluid passes through the valve chest between the coupling member and the valve port, a passable area in a cross section including central axes of both the valve housing and the coupling member, and a minimum passable area among cross sections perpendicular to the central axis of the valve housing and passing through the valve body, are larger than an inner cross-sectional area of the coupling member. A valve device comprising: a cylindrical valve housing having an opening formed on a side surface; a valve element provided in a valve chamber inside the valve housing; a valve port to which the valve element approaches or moves away; a cylindrical coupling member connected to the valve housing by being inserted through the opening; a stepping motor; and a screw feed mechanism that converts rotational motion generated by the stepping motor to linearly move the valve element ,
The stepping motor includes a magnet rotor, a stator coil, and a rotor shaft fixed to the magnet rotor,
the valve body includes a valve holder rotatable about the rotor shaft, a valve body moving toward and away from the valve port, and a compression coil spring provided in the valve holder and biasing the valve body toward the valve port,
an end surface of the coupling member that is inserted into the valve housing is in contact with a virtual inner circumferential surface that is a virtual extension of an inner circumferential surface of the valve housing to the opening, or is disposed outside the virtual inner circumferential surface,
a valve device characterized in that, in a flow path in which a fluid passes through the valve chest between the coupling member and the valve port, a passable area in a cross section including central axes of both the valve housing and the coupling member, and a minimum passable area among cross sections perpendicular to the central axis of the valve housing and passing through the valve body, are larger than an inner cross-sectional area of the coupling member. A guide member for guiding the valve body is further provided,
2. The valve device according to claim 1, wherein in a flow path between the coupling member and the valve port, in which a fluid passes through the valve chamber, a minimum passable area of a cross section that is perpendicular to a central axis of the valve housing and passes through the valve body or the guide member within a range obtained by imaginarily extending the coupling member into the valve chamber is larger than an inner cross-sectional area of the coupling member. A valve device comprising: a cylindrical valve housing having an opening formed on a side surface; a valve element provided in a valve chamber inside the valve housing; a valve port to which the valve element approaches or moves away; a cylindrical coupling member connected to the valve housing by being inserted through the opening; a stepping motor; and a screw feed mechanism that converts rotational motion generated by the stepping motor to linearly move the valve element ,
an end surface of the coupling member that is inserted into the valve housing is in contact with a virtual inner circumferential surface that is a virtual extension of an inner circumferential surface of the valve housing to the opening, or is disposed outside the virtual inner circumferential surface,
in a flow path in which a fluid passes through the valve chest between the coupling member and the valve port, a passable area in a cross section including central axes of both the valve housing and the coupling member, and a minimum passable area among cross sections perpendicular to the central axis of the valve housing and passing through the valve body are larger than an inner cross-sectional area of the coupling member,
a guide member that guides the valve body on the valve port side of the screw feed mechanism ,
a valve device comprising: a valve body having a valve passage between the coupling member and the valve port, the valve body having a valve passage extending from the coupling member into the valve chamber; a valve housing having a valve element and a valve port, the valve body having a valve passage extending from the coupling member into the valve chamber; 4. The valve device according to claim 1, wherein the inner circumferential surface of the valve housing and the imaginary inner circumferential surface extend along a cylindrical surface. 5. The valve device according to claim 1 , wherein an inner diameter of the coupling member is larger than a maximum outer diameter of the valve body. an end surface of the coupling member that is inserted into the valve housing extends along a plane perpendicular to a central axis of the coupling member,
7. The valve device according to claim 1 , wherein the entire end face is located inside an outer circumferential surface of the valve housing. The valve device according to any one of claims 1 to 7, characterized in that the opening is formed with an insertable portion into which the coupling member can be inserted, and a restricting portion that protrudes toward an inner diameter side on the inside of the insertable portion to restrict insertion of the coupling member. 9. The valve device according to claim 8 , wherein a minimum inner diameter of the restriction portion is equal to or larger than an inner diameter of the coupling member. 10. The valve device according to claim 9 , wherein a protruding dimension of the restricting portion toward an inner diameter side from the insertable portion is 50% or less of a wall thickness of the coupling member.