JP3128641B2 - Flow control valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art Conventionally, a flow control valve shown in FIG. 4 has been known.

That is, the flow control valve includes a rod 4 that moves in the axial direction by the operation of a driving unit such as the motor 1. The rod 4 is moved in the axial direction, and one end ( The size of the gap between the valve body 5 provided at the lower end portion) and the valve seat 9 provided inside the housing 8 so as to face the valve body 5 is adjusted.
The flow rate of the fluid flowing from the outlet port 11 to the outlet port 11, particularly the compressible fluid such as air, is controlled. The rod 4 is prevented from rotating with respect to the housing 8 by a non-circular cross-section detent part 6 provided in the middle abdomen, and the other end (upper end) of this rod 4 Is provided with a male screw portion 7 which is screwed into the screw. When the motor 1 operates and the rotor 2 of the motor 1 rotates, the female screw portion 3 is driven to rotate,
Accordingly, the rod 4 moves in the axial direction to change the size of the gap. A spring 12 constantly elastically urges the rod 4 in the valve closing direction for the purpose of eliminating play of the screwing of the female screw portion 3 and the male screw portion 7 (play of the rod 4). And a spring seat 15 provided on the rod 4.

However, in the flow control valve having the above-described structure, as shown in FIG. 5, the valve closing force (retraction force) due to fluid pressure is present at almost all stroke positions except a large flow rate region.
Acts, and the valve closing force of the spring 12 is always applied to this valve closing force. Therefore, a large torque is required to open the valve, and accordingly, a driving source such as the motor 1 having a large size (standard) must be used or the opening / closing speed must be reduced. There is an inconvenience.

[0005]

SUMMARY OF THE INVENTION In view of the above, the present invention has a structure in which the fluid pressure and the valve closing force of a spring do not have a great effect on the valve opening operation. It is an object of the present invention to provide a flow control valve capable of reducing the speed of the valve opening operation.

[0006]

In order to achieve the above object, a flow control valve according to the present invention comprises a rod which moves in the axial direction by the operation of a drive unit such as a motor, a valve provided on the rod, A valve seat provided so as to face the valve body, a first spring for elastically biasing the rod in a valve closing direction, and a spring holding member disposed on the outer peripheral side of the rod so as to be relatively movable in the axial direction. A first stopper provided on the outer peripheral side of the rod and stopping relative movement of the spring holding member in the valve opening direction at a predetermined position; and a first stopper and the spring holding member and the first stopper. A second spring that elastically biases the rod in the valve opening direction, and stops the movement of the spring holding member in the valve opening direction at a predetermined position, and at that time, elastically biases the second spring. A second stopper to be released, Provided, the spring force of the second spring and to be set larger than the spring force of the first spring.

[0007]

In the flow control valve of the present invention having the above-described structure, the first spring resiliently biases the rod in the valve closing direction, while the second spring operates via the spring holding member and the first stopper. The same rod is elastically biased in the valve opening direction,
The spring force of the second spring is set to be larger than the spring force of the first spring. Also, the former first spring resiliently biases the rod in its full stroke, while the latter spring pushes the rod from the fully closed position to the position where the spring holding member abuts the second stopper. Elastic bias between them. Therefore, the following operation will occur from the combination of these two springs.

That is, from the fully closed position to the position where the spring holding member abuts on the second stopper, the two springs respectively resiliently urge the rod, but the spring force of the second spring is reduced. Therefore, the combined force of the two springs acts in the valve opening direction as a whole. Therefore, the backlash of the rod is absorbed by the rod being elastically urged in the valve opening direction and pressed in the same direction, and at the same time, a part or all of the valve closing force due to the fluid pressure is offset, and the valve is opened with a small torque. It is possible to do. On the contrary,
When the spring holding member contacts the second stopper, the spring holding member does not move further in the valve opening direction, only the rod further moves in the valve opening direction, and the first stopper moves away from the spring holding member. go. Therefore, at this point, the elastic bias by the second spring is released, and only the first spring elastically biases the rod in the valve closing direction, whereby the backlash of the rod causes the rod to move in the valve closing direction. It is absorbed by being elastically urged and pressed in the same direction. At this point, the valve has already entered a large flow region in which it is not necessary to consider the effect of the valve closing force due to the fluid pressure.

[0009]

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

As shown in FIG. 1, the flow control valve according to the present embodiment includes a rod 4 which moves in the axial direction by the operation of a driving unit such as a motor 1, and the rod 4 is moved in the axial direction. The size of the gap between the valve body 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 valve body 5 is adjusted. Thus, the flow rate of the fluid flowing from the inflow port 10 to the outflow port 11, in particular, the compressible fluid such as air is controlled. The rod 4 is prevented from rotating with respect to the housing 8 by a non-circular cross-section detent part 6 provided in the middle abdomen, and the other end (upper end) of this rod 4 Is provided with a male screw portion 7 which is screwed into the screw. The first spring 12 constantly elastically urges the rod 4 in the valve closing direction for the purpose of eliminating play of the screwing of the female screw portion 3 and the male screw portion 7 (play of the rod 4). 12 is interposed between a seal holding member 14 holding a seal 13 and a spring seat 15 provided on the rod 4. Reference numeral 2 denotes a rotor of the motor 1.

An annular spring holding member 16 is disposed on the outer peripheral side of the rod 4 on the valve seat 9 side (lower side) of the spring seat 15 so as to be relatively movable in the axial direction. Is stopped by the inner peripheral edge of the spring holding member 16 engaging with the outer peripheral edge of the spring seat 15, that is, the spring seat 15 is The first stopper 17 stops the relative movement toward the valve opening direction at a predetermined position. The first stopper 17 is provided between the valve seat 9 and the spring holding member 16. A second spring 18 that elastically urges the rod 4 in the valve opening direction via a stopper 17 is provided. The spring force of the second spring 18 is the first spring 1
2 is set to be larger than the spring force. When the spring holding member 16 moves in the valve opening direction, the spring holding member 16
Is engaged with the cylindrical portion 14a of the seal holding member 14, and the movement of the spring holding member 16 is stopped. That is, the cylindrical portion 14a of the seal holding member 14 The movement in the direction is stopped at a predetermined position, and at that time, it acts as a second stopper 19 for releasing the elastic bias by the second spring 18.

The flow control valve having the above-described structure operates as follows with respect to the valve opening operation.

That is, the spring holding member 16 is moved from the fully closed position.
Up to the position where the second spring 19 contacts the second stopper 19, the two springs 12 and 18 resiliently urge the rod 4, respectively. However, since the spring force of the second spring 18 is greater, As a total, the combined force of the two springs 12, 18 acts in the valve opening direction as shown in FIG. Therefore, the backlash of the rod 4 is absorbed by the rod 4 being elastically urged in the valve opening direction and pressed in the same direction, and as shown in FIG. 3, a part or all of the valve closing force due to the fluid pressure is reduced. It is possible to cancel and open the valve with a small torque.

On the other hand, when the spring holding member 16 contacts the second stopper 19, the spring holding member 16 does not move further in the valve opening direction, and only the rod 4 moves further in the valve opening direction. As a result, the first stopper 17 moves away from the spring holding member 16. Therefore, at this time, the elastic bias by the second spring 18 is released, and only the first spring 12 elastically biases the rod 4 in the valve closing direction. Is elastically urged in the valve closing direction and pressed in the same direction to be absorbed. Also, at this point, the valve has already entered a large flow region where it is not necessary to consider the effect of the valve closing force due to the fluid pressure.
Therefore, the valve can be opened with a small torque. Further, the valve closing operation can be started with a small torque without being hindered by the large spring force of the second spring 18.

Therefore, it is possible to provide a structure in which the fluid pressure and the valve closing force by the spring do not greatly affect the valve opening operation over the entire stroke of the rod 4, thereby providing a drive source for the motor 1 and the like. Can be downsized, or the valve opening operation can be speeded up.

In the above embodiment, the first stopper 17
Is provided on the spring seat 15, and the second stopper 19 is provided on the seal holding member 14. However, separate stopper portions (stopper members) are provided separately from the spring seat 15 or the seal holding member 14. Is also good.

[0017]

The present invention has the following effects.

That is, in addition to the first spring that elastically urges the rod in the valve closing direction, a second spring that elastically urges the same rod in the valve opening direction is provided. Since the spring force of the second spring is set larger, the combined force of the first spring and the second spring can push the rod in the valve opening direction to eliminate backlash of the rod and close the rod by fluid pressure. It is possible to cancel a part or all of the valve force and open the valve with a small torque. After the spring holding member abuts on the second stopper, the elastic bias of the second spring is released. At this point, the valve can be opened with a small torque because the valve is already in the large flow region where it is not necessary to consider the effect of the valve closing force due to the fluid pressure. is there. Further, the valve closing operation can be started with a small torque without being hindered by the large spring force of the second spring. Therefore, from these, it is possible to provide a structure in which the fluid pressure and the valve closing force by the spring do not greatly affect the valve opening operation over the entire stroke of the rod. The drive source can be reduced in size or the valve opening operation can be accelerated.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a flow control valve according to an embodiment of the present invention.

FIG. 2 is a graph showing a relationship between a spring force of a first spring and a spring force of a second spring in the flow control valve.

FIG. 3 is a graph showing a relationship between a combined force of a first spring and a second spring and a valve closing force (retraction force) by a fluid in the flow control valve.

FIG. 4 is a sectional view of a flow control valve according to a conventional example.

FIG. 5 is a graph showing a relationship between a spring force and a valve closing force (retraction force) by a fluid in the flow control valve.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Motor 2 Rotor 3 Female thread part 4 Rod 5 Valve body 6 Detent part 7 Male thread part 8 Housing 9 Valve seat 10 Inflow port 11 Outflow port 12 First spring 13 Seal 14 Seal holding member 14a Tube part 15 Spring seat 16 Spring holding Member 17 First stopper 18 Second spring 19 Second stopper

Claims (1)

(57) [Claims] 1. A rod (4) that moves in the axial direction by operation of a drive unit such as a motor (1), a valve element (5) provided on the rod (4), and the valve element (5). A valve seat (9) provided so as to oppose, a first spring (12) for elastically biasing the rod (4) in the valve closing direction, and an axial direction relative to the outer peripheral side of the rod (4). A spring holding member (16) movably disposed, and a first stop provided at an outer peripheral side of the rod (4) and stopping relative movement of the spring holding member (16) in a valve opening direction at a predetermined position. A second spring (18) for elastically urging the rod (4) in the valve opening direction via the spring holding member (16) and the first stopper (17); When the movement of the spring holding member (16) in the valve opening direction is stopped at a predetermined position, A second stopper (19) for releasing the elastic bias by the second spring (18), and the spring force of the second spring (18) is reduced by the spring of the first spring (12). Flow control valve set larger than force.