阅读说明：本技术 流量控制阀 (Flow control valve ) 是由 近藤广茂 于 2019-12-24 设计创作，主要内容包括：本发明包括：阀壳(2),其包括主室(5)和副室(6)；阀座(14),其设置在阀壳(2)内部；阀体(25),其可安置在阀座(14)上；针(17),其与阀体(25)相邻；马达机构,其用于使针(17)沿针(17)的轴向方向移动以在阀体(25)安置在阀座(14)上的关闭状态与阀体(25)从阀座(14)缩回的打开状态之间切换；压力接收室(26),其设置在阀体(25)的上表面；以及传导路径,其设置在阀体(25)内,由第一连通槽(23)和第二连通槽(24)构成,并且使副室(6)和压力接收室(26)连通。构成压力接收室(26)的下表面的阀体(25)的上表面的直径(PB)稍小于构成副室(6)的上表面的阀体(25)的下表面的直径(PA)。(The invention comprises the following steps: a valve housing (2) comprising a main chamber (5) and a sub-chamber (6); a valve seat (14) provided inside the valve housing (2); a valve body (25) which can be placed on the valve seat (14); a needle (17) adjacent to the valve body (25); a motor mechanism for moving the needle (17) in the axial direction of the needle (17) to switch between a closed state in which the valve body (25) is seated on the valve seat (14) and an open state in which the valve body (25) is retracted from the valve seat (14); a pressure receiving chamber (26) provided on an upper surface of the valve body (25); and a conduction path that is provided in the valve body (25), that is configured from a first communication groove (23) and a second communication groove (24), and that communicates the sub-chamber (6) and the pressure receiving chamber (26). The diameter (PB) of the upper surface of the valve body (25) constituting the lower surface of the pressure receiving chamber (26) is slightly smaller than the diameter (PA) of the lower surface of the valve body (25) constituting the upper surface of the sub chamber (6).)

1. A flow control valve comprising:

a valve housing having a main chamber as an inlet portion and a sub-chamber as an outlet portion;

a valve seat disposed inside the valve housing;

a valve body capable of seating on the valve seat;

a plunger adjacent to the valve body;

a drive unit configured to move the plunger in an axial direction of the plunger to switch between a closed state in which the valve body is seated on the valve seat and an open state in which the valve body is retracted from the valve seat;

a pressure receiving chamber provided between an upper surface of the valve body and the driving unit; and

a conduction path that is provided along the axial direction of the plunger and that communicates the sub-chamber and the pressure receiving chamber,

wherein the upper surface of the valve body constitutes a lower surface of the pressure receiving chamber, the lower surface of the valve body constitutes an upper surface of the sub chamber, and an area of the upper surface of the valve body is larger than an area of the lower surface of the valve body.

2. The flow control valve of claim 1, wherein the valve body comprises:

an upper valve body, an upper surface of which constitutes the lower surface of the pressure receiving chamber; and

a lower valve body, a lower surface of which constitutes the upper surface of the sub chamber,

the flow control valve further includes a biasing member located between the upper valve body and the lower valve body, the biasing member biasing the upper valve body and the lower valve body away from each other.

Technical Field

The technology disclosed in the present application relates to a flow control valve that adjusts a valve opening degree (opening area) using an electric drive device such as a motor or the like to control the flow rate and pressure of various types of fluids such as gas and liquid.

Background

For example, a conventional flow control valve that adjusts a valve opening degree (opening area) using a driving device such as a motor to control the flow rate and pressure of various types of fluids such as gas and liquid is disclosed in patent document 1.

Patent document 1 discloses an electric valve including: a valve housing in which a first opening and a second opening are formed; an annular valve seat portion provided in the valve housing in communication with the second opening; a cylindrical portion provided in the valve housing such that a central axis thereof is arranged on an axial line of a central axis of the valve seat portion and such that one end thereof is opposed to the valve seat portion at a certain interval; a valve member housed inside the cylindrical portion so as to be movable in a piston-like manner; a pressure balance path provided on the valve housing or the valve member so as to communicate a back pressure chamber formed by a space inside the cylinder portion divided by the valve member on the other side in the cylinder portion with the second opening; and a valve member moving means that moves the valve member to be seated on or released from the valve seat portion, wherein an area in a plan view inside the annular tip portion of the valve member is equal to an area in a plan view of a back pressure chamber side of the valve member inside the cylindrical portion.

CITATION LIST

Patent document

Patent document 1: japanese patent No. 6043152.

Disclosure of Invention

Technical problem

A problem in a flow rate control valve using a driving means such as a motor is a driving torque required to move a valve member up and down and backlash generated during the up and down movement. The problem with the electrically operated valve disclosed in patent document 1 is that: although the drive torque can be reduced by making the area in plan view of the inside of the annular tip portion of the valve member equal to the area in plan view of the back pressure chamber side of the valve member inside the cylindrical portion, backlash cannot be reduced.

The technique disclosed in the present application has been made in view of the above-mentioned problems, and an object thereof is to provide a flow control valve capable of reducing a driving torque of a motor as a driving means and controlling backlash generated during up-and-down movement of a valve member.

Means for solving the problems

To achieve the above object, the flow control valve according to claim 1 is a flow control valve comprising: a valve housing having a main chamber as an inlet portion and a sub-chamber as an outlet portion; a valve seat disposed inside the valve housing; a valve body capable of being seated on the valve seat; a plunger adjacent the valve body; a drive unit configured to move the plunger in an axial direction of the plunger to switch between a closed state in which the valve body is seated on the valve seat and an open state in which the valve body is retracted from the valve seat; a pressure receiving chamber provided between an upper surface of the valve body and the drive unit; and a conduction path that is provided along an axial direction of the plunger and that communicates the sub-chamber and the pressure receiving chamber,

wherein the upper surface of the valve body constitutes the lower surface of the pressure receiving chamber, the lower surface of the valve body constitutes the upper surface of the sub-chamber, and the area of the upper surface of the valve body is larger than the area of the lower surface of the valve body.

The flow control valve according to claim 2 is the flow control valve according to claim 1, wherein the valve body includes an upper valve body whose upper surface constitutes a lower surface of the pressure receiving chamber and a lower valve body whose lower surface constitutes an upper surface of the sub-chamber, and a biasing member located between the upper valve body and the lower valve body, the biasing member biasing the upper valve body and the lower valve body away from each other.

Effects of the invention

In the flow control valve according to claim 1, the pressure receiving chamber and the secondary side on the upper surface side of the valve body (valve member) are connected with the conduction path (pressure balance path), and the area of the upper surface of the valve body is slightly larger than the area of the lower surface of the valve body, whereby the force exerted in the axial direction of the valve body is balanced in a state where a force is slightly exerted upward (in the valve opening direction). (this is a state in which the valve body is raised toward the upper surface side). This makes it possible to reduce backlash generated when the valve body moves up and down. Further, by reducing the area difference between the upper surface of the valve body and the lower surface of the valve body to the extent necessary to reduce backlash, the pressure difference applied to the upper surface and the lower surface of the valve body can be reduced, so that the driving torque necessary when the valve body moves up and down can be reduced. Therefore, the upward and downward movements of the valve body become smooth, and the motor used in the drive unit can be made smaller. This makes it possible to provide a flow control valve capable of performing effective flow control at low cost.

In the flow control valve according to claim 2, the valve body is divided into an upper valve body and a lower valve body in the axial direction, and a biasing member is provided between the upper valve body and the lower valve body to bias the two components away from each other, so that when the flow control valve is closed with the lower valve body seated on the valve seat, if the secondary chamber side undergoes an abnormal rise in pressure due to a water hammer or the like, the lower valve body will rise against the biasing force of the biasing member to open the valve, whereby the pressure can leak to the primary side so that damage to the secondary side can be prevented. In addition, in the case where the valve is closed, when the valve body is seated on the valve seat by the drive unit and an excessive force is further applied to the valve body (in the closing direction), the biasing member functions as a buffer, so that it is possible to prevent damage of components (e.g., damage of gears in the drive unit due to gear seizure or the like) that may occur when an excessive force is applied to the valve body.

Drawings

FIG. 1 is a cross-sectional view of a flow control valve according to a first embodiment of the present invention when the valve is closed;

FIG. 2 is a bottom view of the flow control valve;

FIG. 3 is a cross-sectional view of the flow control valve when the valve is open;

fig. 4 is an enlarged cross-sectional view illustrating a pressure introduction path provided to the valve body;

FIG. 5 is a cross-sectional view depicting the pressure relief mechanism as pressure on the secondary side increases;

fig. 6 is a side view and a bottom view showing a needle constituting a valve mechanism;

fig. 7 is a top view, a side view (perspective view), and a bottom view showing a needle nut constituting a valve mechanism;

fig. 8 is a top view, a side view (perspective view), and a bottom view showing a cylinder guide constituting a valve mechanism;

fig. 9 is a top view, a side view (perspective view), and a bottom view showing a cylinder constituting a valve mechanism; and is

Fig. 10 is a top view, a side view (perspective view), and a bottom view showing a cap constituting a valve mechanism.

Detailed Description

First, a flow control valve 1 according to an embodiment of the present invention will be described with reference to the drawings.

Fig. 1 is a cross-sectional view of the flow control valve 1 in a closed state, and fig. 2 is a bottom view of the flow control valve 1 as viewed from below. The flow control valve 1 has a valve housing 2. At one side of the bottom of the valve housing 2, the first connecting cylinder 3 protrudes in the lateral direction. At the lower side of the bottom of the valve housing 2, the second connector barrel 4 protrudes downward in a direction perpendicular to the central axis of the first connector barrel 3. A main chamber 5 is formed inside the first connecting cylinder 3, and constitutes an inlet side of the fluid. Meanwhile, a sub-chamber 6, which constitutes an outlet side of the fluid, is formed inside the second connecting cylinder 4.

The main chamber 5 and the sub-chamber 6 are formed to be gradually narrowed toward the inside. The interior of the valve housing 2 above the secondary chamber 6 is a substantially cylindrical opening and is provided with a valve chamber 8 which houses a valve mechanism 7 described below. The upper end portion of the valve chamber 8 is open, and at its upper end, in other words, above the valve housing 2, a motor mechanism 10 is attached to the upper surface of the valve housing 2 via an upper cover 9 by screws or the like (not shown). The motor mechanism 10 is constituted by a motor and a drive unit, not shown here, and drives the needle 17 described below to rotate. In the present embodiment, a stepping motor is employed as the motor, but the present invention is not limited thereto, and a DC motor, a gear motor, or the like may also be employed.

The valve chamber 8 is an opening composed of an upper opening 11, a middle opening 12, and a lower opening 13, each formed in a cylindrical shape, formed in this order from the upper side of the figure, the diameter of the upper opening being the largest, the diameter of the middle opening being slightly smaller than the diameter of the upper opening 11, the diameter of the lower opening forming the lower end and being smaller than the diameter of the middle opening 12. At the boundary between the upper opening 11 and the middle opening 12, an upper opening edge 11a is provided. At the boundary between the intermediate opening 12 and the lower opening 13, a valve seat 14 is provided so as to protrude toward the intermediate opening 12. The valve seat 14 has an upper surface in the form of a circular arc, and is formed in a ring shape along the outer periphery of the lower opening 13. As described below, a seat packing 15 is seated on the valve seat 14 when the flow control valve 1 is closed.

A needle support 16 is formed between the sub-chamber 6 and the lower opening 13. As shown in fig. 2, viewing the flow control valve 1 from below, the needle support 16 is constituted by a central cylinder 16a having a through hole 16b at the center thereof through which the lower end of the needle 17 passes, and three ribs 16c, and 16c which are provided at substantially equal intervals and extend radially from the central cylinder 16a toward the inner peripheral surface of the upper opening of the sub-chamber 6. The openings 16d, and 16d between the ribs 16c, and 16c are openings that provide communication between the valve chamber 8 (lower opening 13) and the sub-chamber 6.

Next, the valve mechanism 7 of the flow control valve 1 according to the present invention will be described with reference to the drawings.

The valve mechanism 7 includes: a needle 17 rotated by the motor mechanism 10; a needle nut 18 provided with an internal thread engaging with the external thread of the needle 17; a cylinder guide 19 which fixes the needle nut 18 to the valve housing 2; a cylinder 20 attached at a lower portion of the needle 17 and slidable up and down due to a sliding portion provided at a lower portion of the cylinder guide 19; and a cap 22 attached to the cylinder 20 via a spring 21. The needle nut 18, barrel 20 and cap 22 are mounted for passage of the needle 17. Additionally, the spring 21 is a compression spring that biases the cap 22 downward relative to the barrel 20.

Each component constituting the valve mechanism 7 will be described in detail below.

Fig. 6 shows (a) a side view and (B) a bottom view of the needle 17 as viewed from below. As shown in fig. 6, in the needle 17, a gear portion 17a, a male screw portion 17b, a first needle recess 17c, a second needle recess 17d, a needle body 17e, a cylinder attaching portion 17f, a cap sliding portion 17g, a third needle recess 17h, and a lower end support portion 17i, each of which is in a cylindrical shape having a different diameter, are formed in this order from above in a side view. The gear portion 17a is engaged with a gear (not shown) inside the motor mechanism 10, whereby the needle 17 is controlled by the motor mechanism 10 to rotate. As described above, the male screw portion 17b is engaged with the female screw of the needle nut 18, whereby the needle 17 itself is moved up and down by the rotation of the needle 17. O-rings 30, 31 are fitted into the first needle recess 17c and the second needle recess 17d to maintain the sealed state between the needle 17 and the needle nut 18. The cylinder attaching portion 17f fixes the cylinder by being inserted into the cylinder 20. The cap slide portion 17g is inserted into the cap 22. A stopper plate 27 is installed in the third needle recess 17h to restrict downward movement of the cap 22 into which the needle 17 is inserted.

Fig. 7 shows a plan view of the needle nut 18(a) as viewed from above, (B) a side view (perspective view), and (C) a bottom view as viewed from below. As shown in fig. 7, the needle nut 18 includes a needle nut mounting portion 18a, a needle nut body 18b, a needle nut recess 18c, and a needle nut lower cylindrical portion 18d formed in this order from above in a side view. A needle nut recess 18c is provided at a central portion of the needle nut body 18 b. All of these portions are formed in a cylindrical shape except for the needle nut mounting portion 18 a. As shown in the top view of fig. 7(a), the needle nut mounting portion 18a has a shape in which a part of a cylinder is cut flat, and the needle nut 18 is mounted to the upper cover 9 by inserting the needle nut mounting portion 18a into a mounting hole (not shown) formed in the upper cover 9 to fit the needle nut mounting portion 18 a. Therefore, in a state where the needle nut 18 is attached to the upper cover 9, the rotational movement of the needle nut 18 is restricted. Furthermore, the needle nut 18 is provided with cylindrical needle nut openings 18e, 18f having different opening diameters, which penetrate the needle nut 18 in the vertical direction along its central axis. A female screw is formed around the inner peripheral surface of the needle nut opening 18e to engage with the male screw of the male screw portion 17b of the needle 17. The inside diameter of the needle nut opening 18f is slightly larger than the outside diameter of the needle body 17e so that the needle body 17e slides within the needle nut opening 18f when the needle 17 moves up and down. An O-ring 28 is fitted in the needle nut recess 18c to maintain the sealed state between the needle nut 18 and the cylinder guide 19.

Fig. 8 shows a plan view of the cylinder guide 19(a) as viewed from above, (B) a side view (perspective view), and (C) a bottom view as viewed from below. As shown in fig. 8, in the cylinder guide 19, a cylinder guide mounting portion 19a, a cylinder guide main body 19b, a cylinder guide recess 19c, a cylinder guide intermediate cylindrical portion 19d, and a cylinder guide lower cylindrical portion 19e, each of which has a cylindrical shape with a different diameter, are formed in this order from above in a side view. A cylinder guide recess 19c is provided at a central portion of the cylinder guide body 19 b. Further, the cylinder guide 19 is provided with cylindrical cylinder guide openings 19f, 19g, 19h different in opening diameter, which penetrate the cylinder guide 19 in the vertical direction along the center axis of the cylinder guide 19. The cylinder guide opening 19f is formed to accommodate the needle nut body 18b, and as described above, when the needle nut 18 is accommodated within the cylinder guide 19, the O-ring 28 is fitted into the needle nut recess 18c to maintain the sealed state between the needle nut 18 and the cylinder guide 19.

The outer diameter of the cylinder guide body 19b is slightly smaller than the inner diameter of the upper opening 11, so that the fitting of the O-ring 29 into the cylinder guide recess 19c maintains the sealed state between the cylinder guide 19 and the inner peripheral surface of the valve housing 2. Further, since the edge at the lower end of the cylinder guide body 19b abuts the upper opening edge 11a, downward movement of the cylinder guide 19 is restricted when the cylinder guide 19 is mounted in the valve housing 2. Therefore, the cylinder guide 19 is held in the upper opening 11 of the valve chamber 8 in a state where the needle nut 18 is accommodated. The opening diameter of the cylinder guide opening 19h is set slightly larger than the outer diameter of the cylinder main body 20a of the cylinder 20 to such an extent that the cylinder 20 described below can slide in the vertical direction.

Fig. 9 shows a top view of the cylinder 20(a) as viewed from above, (B) a side view (perspective view), and (C) a bottom view as viewed from below. As shown in fig. 9, in the cylinder 20, a cylinder main body 20a, a first cylinder recess 20b, a cylinder lower portion 20c, and a second cylinder recess 20d, each of which has a cylindrical shape with a different diameter, are formed in this order from above in a side view. The first cylindrical recess portion 20b is provided at a central portion of the cylindrical body 20a, and the second cylindrical recess portion 20d is provided at a lower position of the cylindrical lower portion 20 c. Further, the cylinder 20 is provided with cylindrical cylinder openings 20e, 20f having different opening diameters, which penetrate the cylinder in the vertical direction along the center axis of the cylinder 20. Further, formed in the inner peripheral surface of the cylindrical opening 20f are: a first cylindrical groove 20g extending outwardly at an upper end thereof to an inner peripheral surface of the cylindrical opening 20 e; and a first cylinder groove 20h communicating with the first cylinder groove 20g and extending downward to a lower end surface of the cylinder 20 along an inner peripheral surface of the cylinder opening 20 f. In the present embodiment, as shown in fig. 9, first communicating grooves 23 composed of first cylindrical grooves 20g and first cylindrical grooves 20h are formed at three positions at substantially equal intervals in the inner surface of the cylindrical opening 20 f.

The cylinder openings 20e, 20f are respectively formed such that the inner diameter of the cylinder opening 20e is adapted to the outer diameter of the needle body 17e, and the inner diameter of the cylinder opening 20f is adapted to the outer diameter of the cylinder attaching portion 17f of the needle 17, and the cylinder 20 is attached to the needle 17 in a state in which the needle 17 is inserted therein. In addition, O-rings 32, 33 are fitted into the first cylinder recess 20b and the second cylinder recess 20d, respectively, to maintain the sealed state between the cylinder 20 and the cylinder guide 19 and between the cylinder 20 and the cap 22, respectively.

Fig. 10 shows a plan view of the cap 22(a) as viewed from above, (B) a side view (perspective view), and (C) a bottom view as viewed from below. As shown in fig. 10, the cap 22 is formed with, in order from above in a side view: a cylindrical cap body 22 a; a truncated cone-shaped upper flange 22b which expands outward toward the bottom; a cylindrical cap recess 22 c; and a truncated cone-shaped lower flange 22d that narrows inwardly toward the bottom. A ring-shaped seat packing 15 formed as an elastic member is fitted in the cap recess 22c, and is seated on the valve seat 14 when the flow control valve 1 is closed.

Further, the cap 22 is provided with cylindrical cap openings 22e, 22f, 22g, 22h having different opening diameters, which penetrate the cap 20 in the vertical direction along the central axis thereof. The inner diameter of the cap opening 22e is slightly larger than the outer diameter of the cylinder lower portion 20c so that the cylinder lower portion 20c can slide in the vertical direction within the cap opening 22 e. The cap opening 22f has an inner diameter slightly smaller than that of the cap opening 22e, and is provided with a spring 21 that biases the cap 22 relative to the barrel 20. The inner diameter of the cap opening 22g is slightly larger than the outer diameter of the cap sliding portion 17g of the needle 17 so that the cap sliding portion 17g of the needle 17 can slide in the cap opening 22g in the vertical direction. Further, a cap groove 22i extending in the vertical direction and constituting a second communication groove 24 is formed in the inner surface of the cap opening 22 g. In the present embodiment, as with the first communication grooves 23, second communication grooves 24 (cap grooves 22i) are formed at three positions at substantially equal intervals in the inner surface of the cap opening 22 g.

Since the cylinder 20 is attached to the needle 17 and the cap 22 is attached to the cylinder 20 via the spring 21 as described above, the cylinder 20 and the cap 22 move up and down together with the needle 17 as a whole, and since the flow control valve 1 is opened and closed by the seat packing 15 mounted on the cap 22, the cylinder 20 and the cap 22 together function as the valve body 25 of the flow control valve 1.

Next, the operation and effect of the valve mechanism 7 of the flow control valve constructed as described above according to the present invention will be described. As described above, fig. 1 is a cross-sectional view of the flow control valve 1 when the valve is closed, and fig. 3 is a cross-sectional view of the flow control valve 1 when the valve is open.

When the flow control valve 1 is closed, the motor mechanism 10 rotates the needle 17 as indicated by an arrow (1) in fig. 1. As described above, since the needle nut 18 is fixed in the valve chamber 8, the needle 17 moves downward as it rotates, which also causes the valve body 25 composed of the cylinder 20 and the cap 22 to move downward as it rotates, as shown in fig. 1, so that the seating packing 15 of the valve body 25 is seated on the valve seat 14, whereby the flow control valve 1 is closed. When the flow control valve 1 is opened, as shown by arrows (1) and (2) in fig. 3, the needle 17 is rotated by the motor mechanism 10 to move upward in a direction opposite to the direction when the valve is closed, which also causes the valve body 25 composed of the cylinder 20 and the cap 22 to move upward, as shown in fig. 3, so that the seating packing 15 of the valve body 25 is separated from the valve seat 14, whereby the flow control valve 1 is opened. As shown by the arrow (3) in fig. 3, the fluid flows from main chamber 5 into sub-chamber 6. The flow control valve 1 can control the flow rate of the fluid flowing from the main chamber 5 to the sub-chamber 6 by placing the seat packing 15 of the valve body 25 on the valve seat 14 using the motor mechanism 10 or changing the opening degree between the seat packing 15 of the valve body 25 and the valve seat 14 when opening the valve. In addition, since the valve body 25 is constituted of the cylinder 20 and the cap 22 (including the seat packing 15) via the spring 21, if the needle 17 is rotated too far while the flow control valve 1 is closed, the spring 21 functions as a buffer, which can prevent damage to components due to excessive rotation of the needle 17.

Fig. 4 is an enlarged cross-sectional view of a portion of the valve body 25 (the cylinder 20 and the cap 22) of the flow control valve 1. As described above, the cylinder 20 is provided with the first communicating groove 23 extending in the vertical direction of the cylinder 20, and the cap 22 is provided with the second communicating groove 24 extending in the vertical direction of the cap 22. Therefore, the pressure receiving chamber 26 surrounded by the upper surface of the valve body 25 (the upper surface of the cylinder 20) and the cylinder guide opening 19h of the cylinder guide 19 communicates with the sub-chamber 6 via the first communicating groove 23 and the second communicating groove 24. Therefore, as indicated by an arrow (1) in fig. 4, the fluid flows from the sub-chamber 6 into the pressure receiving chamber 26, so that the pressure in the pressure receiving chamber 26 becomes approximately equal to the pressure in the sub-chamber 6. In other words, the pressure in the pressure receiving chamber 26 becomes approximately equal to the secondary-side pressure.

As shown in fig. 4, in the flow control valve 1 according to the present invention, the diameter PB of the upper surface of the valve body 25 is set slightly larger than the diameter PA of the lower surface of the valve body 25. Therefore, the valve body 25 will always be in a state of slightly applying a force upward (in the valve opening direction). (this is a state in which the valve body 25 is raised toward the upper surface side). Therefore, backlash generated in the motor mechanism 10 when the valve body 25 moves up and down can be reduced. This allows the valve body 25 to move up and down smoothly.

In addition, the pressure difference exerted on the upper surface and the lower surface of the valve body 25 can be reduced by reducing the backlash in the motor mechanism 10 to a desired degree by means of the difference between the area of the upper surface of the valve body 25 (diameter PB) and the area of the lower surface of the valve body 25 (diameter PA). This makes it possible to reduce the starting torque required to start the motor mechanism 10 when the valve body 25 is to be moved up and down.

In this way, the flow control valve 1 according to the present invention allows the valve body 25 to smoothly move upward and downward, which is advantageous in controlling the flow rate of fluid, and allows the motor in the motor mechanism 10 to be miniaturized due to the reduction of the starting torque of the motor, so that it is possible to provide a flow control valve capable of performing effective flow control at low cost.

Next, a case where the secondary side connected to the secondary chamber 6 experiences an abnormal rise in pressure due to a water hammer or the like when the flow control valve 1 is closed will be described with reference to fig. 5. Fig. 5 is a cross-sectional view illustrating a pressure release mechanism when the pressure on the secondary side is raised in the flow control valve 1 according to the present invention.

When the flow control valve 1 is closed, as indicated by arrow (1) in fig. 5, when an abnormal rise in pressure due to a water hammer or the like occurs in the secondary side connected to the secondary chamber 6, in the valve body 25, as indicated by arrow (2) in fig. 5, the cap 22 will move upward against the biasing force of the spring 21. This causes the seated packing 15 of the valve body 25 to separate from the valve seat 14 as indicated by an arrow (3) in fig. 5, allowing the pressure on the secondary side to escape into the main chamber 5 as the primary side, thus preventing damage to components and the like on the secondary side. In other words, by constituting the valve body 25 by the cylinder 20 and the cap 22 and attaching the cap 22 to the cylinder 20 by the spring 21, it is possible to easily configure the pressure release mechanism for when an abnormal pressure rise occurs on the secondary side. In addition, as described above, the valve body 25 according to the present embodiment also successfully prevents damage of components due to excessive rotation of the needle 17 when closing the valve.

Here, the main chamber 5 is an example of a main chamber, the sub-chamber 6 is an example of a sub-chamber, the valve housing 2 is an example of a valve housing, the valve seat 14 is an example of a valve seat, the valve body 25 is an example of a valve body, the needle 17 is an example of a plunger, the motor mechanism 10 is an example of a drive unit, the pressure receiving chamber 26 is an example of a pressure receiving chamber, the conduction path composed of the first communication groove 23 and the second communication groove 24 is an example conduction path, the cylinder 20 is an example of an upper valve body, the cap 22 is an example of a lower valve body, and the spring 21 is an example of a biasing member.

The embodiments of the present invention have been described above in detail, but this is merely an example, and it is to be understood that the present invention should not be construed as being equivalent to or limited to the specific description in the above embodiments, but may be practiced in various aspects to which various modifications, alterations, and the like are added based on the knowledge of those skilled in the art, and will fall within the scope of the present invention as long as they do not depart from the spirit and scope of the present invention.

For example, in the above-described embodiment, the valve body 25 is constituted by the cylinder 20 and the cap 22, but in the case where a separate pressure release valve or the like is provided to the secondary side and it is not necessary to provide the pressure release function to the valve body 25 as described above, the valve body 25 may be of a one-piece structure. This allows the number of parts to be reduced, so that the production cost can be reduced.

Further, in the above-described embodiment, the flow rate of the fluid is controlled by rotating the needle 17 by the motor mechanism 10 to move the valve body 25 up and down together with the needle 17, but conversely, the motor mechanism 10 may also rotate the needle nut 18 to move the needle 17 up and down. In this case, since the needle 17 is not rotated, the valve body 25 can also be moved up and down without being rotated. Therefore, since the valve body 25 does not rotate in the fluid, the flow of the fluid from the main chamber 5 to the sub-chamber 6 can be stabilized. In addition, since the abrasion of the O-ring and the seat packing 15 fitted on the valve body 25 can be reduced, the maintainability is also improved.

Further, in the above-described embodiment, the conduction path constituted by the first communication groove 23 and the second communication groove 24 is provided at three positions, but the conduction path is not limited thereto, and may be provided at one position or four or more positions as long as the pressure in the receiving pressure chamber 26 becomes approximately equal to the secondary-side pressure. Further, if a conduction path can be provided inside the needle 17, a conduction path can be provided inside the needle 17.

Further, in the above-described embodiment, the needle support 16 is provided, but this may not be necessary depending on the shape of the needle 17.

Description of the reference numerals

1 flow control valve

2 valve casing

5 Main Chamber

6 auxiliary chamber

7 valve mechanism

8 valve chamber

10 Motor mechanism

14 valve seat

15 setting filler

17 needle

18-pin nut

19 Cylinder guide

20 cylinder

22 cap

23 first connecting groove

24 second communicating groove

25 valve body

26 pressure receiving chamber