JPH0882374A - Needle valve - Google Patents

Abstract

PURPOSE: To provide a needle valve which is constituted to ensure a fine flow rate even in the fully closed state of a needle and also regulate a quantity of fine flow rate and besides prevent the change of the zero point position of the needle and eliminate a need to change control of the drive part of a motor. CONSTITUTION: A needle 5 is provided with a communicating passage 21 to intercommunicate the upper stream space 19 and the downstream space 20 of a valve seat 9 during closing and a second valve seat 22 is arranged at one opening part of the communicating passage 21. Further, a subneedle 24 moved forward to and backward from the second valve seat 22 and making contact with and separable away from the second valve seat 22 is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a needle valve for controlling the flow rate of fluid such as gas.

[0002]

2. Description of the Related Art Conventionally, a needle valve shown in FIG. 6 has been known.

That is, this needle valve is provided with a rod 4 which is moved in the axial direction by the operation of a drive unit such as a motor 1. The rod 4 is moved in the axial direction to obtain one end (lower end) of the rod 4. Part 5) and the size of the gap between the valve seat 9 provided inside the housing 8 so as to face the needle 5, and thereby the gas flowing from the inflow port 10 to the outflow port 11 can be adjusted. Control the flow rate of the fluid. The rod 4 is prevented from rotating with respect to the housing 8 by a detent portion 6 having a non-circular cross section provided in its middle abdomen, and the other end portion (upper end portion) of the rod 4 has a female screw portion 3 The male screw part 7 screwed to is provided. When the motor 1 operates and the rotor 2 of the motor 1 rotates, the female screw portion 3 is driven to rotate, and accordingly, the rod 4 moves in the axial direction to change the size of the gap. Further, for the purpose of eliminating the looseness of the screw engagement between the female screw portion 3 and the male screw portion 7, the spring 12 always keeps the rod 4
The spring 12 is elastically biased in the valve closing direction, and the spring 12 is interposed between a seal holding member 14 holding a seal 13 and a spring seat 15 provided on the needle 5.

However, in the needle valve having the above structure, the rod 4 moves in the valve closing direction and the needle 5 moves.
When the valve seats on the valve seat 9, the flow rate of the fluid becomes zero.
Therefore, for example, when it is necessary to flow a small amount of fluid in the fully closed state such as a pilot fire of a gas water heater or idling of an engine, this needle valve alone cannot handle it. In addition, if this needle valve is equipped with another valve to secure a minute flow rate,
The piping becomes complicated, the entire device becomes large, and the cost is high.

Therefore, as shown in FIG.
A screw hole 16 is provided in the screw hole, and a stopper member 17 that advances and retracts toward the needle 5 is screwed into the screw hole 16, and the stopper member 17 is appropriately advanced and retracted to ensure a minute flow rate even in the fully closed state. Is possible (unknown)
However, in this solution, the zero point position of the needle 5 changes each time the fine flow rate is adjusted, so that
There is the inconvenience of having to change the control of the drive unit such as the motor 1.

[0006]

In view of the above points, the present invention can still secure a minute flow rate in the fully closed state of the needle, and can adjust the amount of this minute flow rate.
Moreover, it is an object of the present invention to provide a needle valve in which the zero point position of the needle does not change and it is not necessary to change the control of a drive unit such as a motor.

[0007]

In order to achieve the above object, a needle valve according to claim 1 of the present invention comprises a rod that moves axially by the operation of a drive unit such as a motor, and a needle provided on the rod. A first valve seat provided so as to face the needle, and a communication passage provided in the needle and connecting the upstream space and the downstream space of the first valve seat when the valve is closed, A second valve seat provided at one opening of the communication passage, and a sub-needle that is provided so as to be capable of advancing and retracting toward the second valve seat and that comes into contact with and separates from the second valve seat. I decided to prepare.

A needle valve according to a second aspect of the present invention is provided with a rod that moves axially by the operation of a drive unit such as a motor, a needle provided on the rod, and a needle that faces the needle. A valve seat, a communication passage provided in the needle and communicating between the upstream space and the downstream space of the valve seat when closing the valve, a normally closed poppet valve provided in the communication passage, and the poppet valve And a pressing member which is provided so as to be capable of advancing and retracting toward the front and which moves forward while pressing the poppet valve and opens the poppet valve in accordance with the degree of the advance.

[0009]

In the needle valve according to claim 1 of the present invention having the above structure, when the needle is seated on the first valve seat and is in the fully closed state, the upstream side space and the downstream side of the first valve seat. The space is communicated with the needle through a communication passage provided in the needle to allow the fluid to flow, and the amount of the fluid flowing through the communication passage is increased or decreased by moving the subneedle forward or backward and the second valve. It can be adjusted by changing the degree of opening with the seat. Therefore, since there is no need to move the needle itself when flowing a small amount of fluid in the fully closed state, the zero point position of the needle is not changed, and control of the drive unit such as the motor is not changed.

Further, in the needle valve according to the second aspect of the present invention, when the needle is seated on the valve seat and is in a fully closed state, the upstream side space and the downstream side space of the valve seat are provided in the communication passage. A fluid is allowed to flow through the communication passage, and the amount of the fluid flowing through the communication passage can be adjusted by advancing and retracting the pressing member to change the opening degree of the poppet valve. Therefore, since there is no need to move the needle itself when flowing a small amount of fluid in the fully closed state, the zero point position of the needle is not changed, and control of the drive unit such as the motor is not changed.

[0011]

Next, an embodiment of the present invention will be described with reference to the drawings.

First Embodiment: As shown in FIG. 1, the needle valve according to the first embodiment is provided with a rod 4 which is axially moved by the operation of a drive unit such as a motor 1. Is moved in the axial direction to provide a gap between a needle 5 provided at one end (lower end) of the rod 4 and a first valve seat 9 provided inside the housing 8 so as to face the needle 5. Adjust the size of the inflow port 1
The flow rate of fluid such as gas flowing from 0 to the outflow port 11 is controlled. The rod 4 is prevented from rotating with respect to the housing 8 by a detent portion 6 having a non-circular cross section provided in its middle abdomen, and the other end portion (upper end portion) of the rod 4 has a female screw portion 3 The male screw part 7 screwed to is provided. The spring 12 constantly elastically biases the rod 4 in the valve closing direction for the purpose of eliminating the looseness of the screw engagement between the female screw portion 3 and the male screw portion 7. The spring 12 holds the seal 13 and holds the seal 13. And the spring seat 1 provided on the needle 5
It is installed between 5. Reference numeral 2 is a rotor of the motor 1, and 18 is a linear sensor.

As shown in the enlarged view of FIGS. 2 and 3, the needle 5 is formed separately from the rod 4 and has a cylindrical shape and is fitted on the outer peripheral side of the one end portion 4a of the rod 4, and The fitting portion is provided with a cutout portion such as a two-sided width so that the needle 5 has the upstream side space 19 of the first valve seat 9 in the fully closed state.
Is provided with a communication passage 21 that communicates with the downstream space 20. A second valve seat 22 is provided outward at an opening on the downstream side of the communication passage 21. On the other hand, a screw hole 23 is provided in the housing 8, and a sub-needle 24 that moves forward and backward toward the second valve seat 22 and that comes into contact with and separates from the second valve seat 22 is screwed into the screw hole 23. Has been done.
25 is a seal.

As described above, the needle valve having the above-mentioned structure operates the driving portion of the motor 1 or the like to move the rod 4 in the axial direction, and the size of the gap between the needle 5 and the first valve seat 9 is small or large. Is adjusted to control the flow rate of fluid such as gas, but it is still possible to flow a small amount of fluid even in the fully closed state, and it is possible to adjust the small flow rate to some extent. . That is, when the needle 5 is seated on the first valve seat 9 and is in the fully closed state, the upstream space 19 and the downstream space 20 of the first valve seat 9 form the communication passage 21 provided in the needle 5. A fluid is allowed to flow through the communication passage 21, and the amount of the fluid flowing in the communication passage 21 is moved forward and backward by the subneedle 24 to change the opening degree between the subneedle 24 and the second valve seat 22. Therefore, it is possible to adjust. Therefore, even in the fully closed state, it is possible to flow a small amount of fluid, and it is possible to adjust the amount of this minute flow rate. Moreover, when flowing a small amount of fluid in the fully closed state, the needle 5 itself is Since there is no need to move it, the zero point position of the needle 5 is not changed, and control of the drive unit such as the motor 1 is not changed.

Second Embodiment: As shown in FIG. 4, the needle valve according to the second embodiment is provided with a rod 4 which is moved in the axial direction by the operation of a drive unit such as the motor 1 and the like. Is moved in the axial direction to reduce the size of the gap between the needle 5 provided at one end (lower end) of the rod 4 and the valve seat 9 provided inside the housing 8 so as to face the needle 5. The flow rate of the fluid such as gas flowing from the inflow port 10 to the outflow port 11 is controlled by the adjustment. The rod 4 is prevented from rotating with respect to the housing 8 by a detent portion 6 having a non-circular cross section provided in its middle abdomen, and the other end portion (upper end portion) of the rod 4 has a female screw portion 3 The male screw part 7 screwed to is provided. The spring 12 constantly elastically biases the rod 4 in the valve closing direction for the purpose of eliminating the looseness of the screw engagement between the female screw portion 3 and the male screw portion 7, and the spring 12 holds the seal 13 to hold the seal 13. And a spring seat 15 provided on the needle 5.
Is intervened between. Reference numeral 2 is a rotor of the motor 1, and 18 is a linear sensor.

As shown in the enlarged view of FIG. 5, the needle 5 is formed separately from the rod 4 and has a tubular shape, and is fitted onto the outer peripheral side of the one end portion 4a of the rod 4, and this fitting is also performed. A notch such as a groove is provided in the portion, and the needle 5 is provided with a communication passage 21 that communicates the upstream space 19 and the downstream space 20 of the valve seat 9 in the fully closed state.
1 is provided with a poppet valve 26. This poppet valve, generally designated by the reference numeral 26, is a normally closed type,
An inward valve seat 27 provided in an opening on the downstream side of the communication passage 21 and a poppet 2 that comes into contact with and separates from the valve seat 27.
8 and a spring 2 for pressing the poppet 28 against the valve seat 27
9, and the poppet 28 is provided with a notch 30 for preventing the poppet 28 from blocking the communication passage 21 and a pin-shaped pressed portion 31. The pin-shaped pressed portion 31 projects from the needle 5 into the downstream space 20. On the other hand, the screw hole 32 in the housing 8
Is provided in the screw hole 32 to advance and retract toward the poppet valve 26, and the poppet 28 of the poppet valve 26.
Of the poppet valve 26 depending on the degree of the forward movement of the poppet valve 26 depending on the degree of the forward movement.
A screw-shaped pressing member 33 for opening the valve is screwed. 34 is a seal.

As described above, the needle valve having the above-mentioned structure operates the driving portion of the motor 1 or the like to move the rod 4 in the axial direction, and adjusts the size of the gap between the needle 5 and the valve seat 9. The flow rate of the fluid such as gas is controlled, but it is possible to flow a small amount of fluid even in the fully closed state, and it is possible to adjust the fine flow rate to some extent. That is, when the needle 5 is seated on the valve seat 9 and is in the fully closed state, the upstream space 19 and the downstream space 20 of the valve seat 9 are communicated with each other via the communication passage 21 provided in the needle 5. The fluid can flow, and the amount of the fluid flowing through the communication passage 21 can be adjusted by moving the pressing member 33 forward and backward to change the opening degree of the poppet valve 26. Therefore, even in the fully closed state, it is possible to flow a small amount of fluid, and it is possible to adjust the amount of this minute flow rate. Moreover, when flowing a small amount of fluid in the fully closed state, the needle 5 itself is Since there is no need to move it, the zero point position of the needle 5 is not changed, and control of the drive unit such as the motor 1 is not changed.

[0018]

The present invention has the following effects.

That is, in common with claim 1 and claim 2, not only is it possible to secure a fine flow rate in the fully closed state of the needle and to adjust the fine flow rate to some extent, but also the zero point of the needle. Since the position does not change, there is no need to change the control of the drive unit such as the motor. Therefore, it is possible to provide a needle valve that is easy to handle and operate.

[Brief description of drawings]

FIG. 1 is a sectional view of a needle valve according to a first embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a main part of the needle valve.

3 is a sectional view taken along line AA in FIG.

FIG. 4 is a sectional view of a needle valve according to a second embodiment of the present invention.

FIG. 5 is an enlarged sectional view of the main part of the needle valve.

FIG. 6 is a cross-sectional view of a needle valve according to a conventional example.

FIG. 7 is a sectional view of a needle valve according to the prior art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Motor 2 Rotor 3 Female screw part 4 Rod 4a One end part 5 Needle 6 Detent part 7 Male screw part 8 Housing 9,22,27 Valve seat 10 Inflow port 11 Outflow port 12,29 Spring 13,25,34 Seal 14 Seal holding member 15 Spring Seat 16, 23, 32 Screw Hole 17 Stopper Member 18 Linear Sensor 19 Upstream Space 20 Downstream Space 21 Communication Passage 24 Sub Needle 26 Poppet Valve 28 Poppet 30 Cutout 31 Pressed Part 33 Pressing Member

Claims (2)

[Claims] 1. A rod (4) that moves in the axial direction by the operation of a drive unit such as a motor (1), a needle (5) provided on the rod (4), and a needle (5) opposed to the needle (5). The first valve seat (9) thus provided, and the upstream space (19) and the downstream space (20) of the first valve seat (9), which are provided on the needle (5) and are closed. And a communication passage (21) for communicating with each other, a second valve seat (22) provided at one opening of the communication passage (21), and freely movable back and forth toward the second valve seat (22). And a sub-needle (24) provided on the second valve seat (22) so as to come into contact with and separate from the second valve seat (22). 2. A rod (4) that moves in the axial direction by the operation of a drive unit such as a motor (1), a needle (5) provided on the rod (4), and the needle (5) facing each other. Communication passage provided in the needle (5) and communicating between the upstream space (19) and the downstream space (20) of the valve seat (9) when closed. (21), a normally-closed poppet valve (26) provided in the communication passage (21), and a poppet valve (26) that is movable toward and away from the poppet valve (26) while pressing the poppet valve (26). A needle valve including a pressing member (33) that moves forward and opens the poppet valve (26) according to the degree of the advance.