JPH043162Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a butterfly valve used mainly to control the flow in a gas distribution path.

[Prior art] Butterfly valves are capable of freely changing the opening of the flow path from fully open to fully closed by rotating the valve plate approximately 90 degrees around its fulcrum.
It is used in various parts of fluid passages that circulate various gases, air, etc. In this type of butterfly valve, as shown in Fig. 5, an example is shown in Fig. 5.
Disc-shaped valve plate 5 installed in pipe D
By rotating the plate around its installation center o in conjunction with the rotation of the operating shaft 1 inserted from the outside, its outer peripheral end 5a is brought into close contact with the seat surface s from the fully open state of the horizontal plate in the flow path. It has a mechanism that allows the opening degree to be changed freely up to the fully closed state in a vertical plate position.

[Problems to be solved by the invention] By the way, when a butterfly valve is used in a vacuum device or the like, in order to ensure a vacuum seal when the butterfly valve is fully closed, an O is placed between the outer peripheral end 5a of the valve plate 5 and the seat surface a. It is common to use a sealing material such as a ring (not shown), but in conventional valve mechanisms, this sealing material cannot be used effectively. That is, the valve plate 5 and the seat surface s
The sealing effect of the sealing material interposed between the two is most effective when it is compressed between the two, but in the conventional butterfly valve, its opening/closing mechanism does not touch the valve plate 5. Since it is rotated around the mounting center o, the outer peripheral end 5a of the valve plate 5 slides parallel to the seat surface s, and if the rotational driving force is weak, the sealing material An accurate closed state may not be obtained due to friction, or the sealing material may be incompletely deformed, resulting in insufficient sealing action. In addition to this operational uncertainty, the sealing material is also rubbed against each other during each opening/closing operation, resulting in other inconveniences such as severe abrasion of the sealing material.

On the other hand, as shown in Japanese Patent Publication No. 42-17230, for example, an operating shaft is provided with an eccentric shaft portion, and the eccentric shaft portion of the operating shaft is fitted to the eccentric shaft portion so as to rotate in synchronism, and only when the rotation is restrained. A plate support shaft that is rotatable relative to the eccentric shaft, a valve plate that is integrally fixed to the plate support shaft, and a stopper that engages with the valve plate to stop the rotation of the plate support shaft. A valve plate having a structure in which the valve plate is brought into close contact with the seat surface has also been developed.

However, with such a configuration, when the plate support shaft moves forward while moving relative to the eccentric shaft after its rotation is restrained, the change in the axial center position of the eccentric shaft causes the plate support shaft to move forward. It is directly transmitted to the valve plate through the valve plate, and appears as a radial displacement of the valve plate. For this reason, if the amount of eccentricity of the eccentric shaft section is set to a large value in order to increase the forward/backward stroke of the valve plate to some extent, the radial displacement of the valve plate will also increase accordingly, and such displacement is not allowed. This creates the inconvenience that the valve housing must be made larger in order to do so.

The present invention was developed with an eye to these problems, and its purpose is to enable the valve plate to be brought into contact with and be removed from the seat surface without sliding, and to provide high sealing performance when the valve is fully closed. It is an object of the present invention to provide a butterfly valve that can ensure the long life of the sealing material and at the same time ensure the life of the sealing material without causing an increase in the size of the structure.

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention includes an operating shaft provided with an eccentric shaft portion, and an actuating shaft that is fitted to the eccentric shaft portion of the operating shaft so as to be rotatable in synchrony with the A plate support shaft that can rotate relative to the eccentric shaft only when restrained, a valve plate that is attached to the plate support shaft so as to be relatively slidable in the radial direction via a slide mechanism and rotates together with the plate support shaft, and the valve. To provide a butterfly valve constituted by a rotation stopper for stopping rotation of a plate in an attitude parallel to a seat surface.

[Operation] The butterfly valve having the above configuration operates as follows. First, the valve closing operation is performed by rotating the operating shaft in a predetermined valve closing direction, and at this time, the plate support shaft rotates in synchronization with the operating shaft, and the valve plate rotates together with it. When the valve plate rotates to a position parallel to its seat surface, a rotation stopper acts to prevent further rotation of the valve plate, and at the same time, the rotation of the plate support shaft is restrained, so that the operating shaft is no longer rotated. When rotated, the operating shaft rotates independently. However, since the plate support shaft is fitted to the eccentric shaft portion of the operating shaft, the plate support shaft can be moved forward in a direction perpendicular to the operating shaft relative to the relative rotation of the operating shaft, and as a result, the plate support shaft The valve plate attached to the support shaft can be pressed against the seat surface while remaining parallel to the seat surface.

The valve opening operation is then performed by rotating the operating shaft in the opposite direction. In other words, when the operating shaft is reversed from the fully closed state of the valve, since the valve plate is prevented from rotating by the seat surface, only the operating shaft rotates, and the valve plate along with the plate support shaft temporarily retreats and leaves the seat surface, and then The plate support shaft rotates in synchronization with the operating shaft, the valve plate rotates, and the valve opening degree increases until it reaches a fully open position.

In this way, when the valve is closed or opened, the valve plate moves forward and backward parallel to the seat surface and comes into contact with and separates from the seat surface, which causes the disadvantage that its outer peripheral edge slides against the seat surface. can be reliably avoided.

Moreover, when the plate support shaft moves forward while moving relative to the eccentric shaft after its rotation is restrained, the change in the axial center position of the eccentric shaft is transmitted to the plate support shaft, but the plate support shaft Since the valve plate and the valve plate can be slid relative to each other via the slide mechanism, from then on, even if the plate support shaft is displaced in the radial direction of the valve plate, the valve plate cannot be displaced radially from that position. Instead, it only moves forward toward the seat surface. Therefore, even if the eccentricity of the eccentric shaft portion is set to a large value in order to increase the forward and backward stroke of the valve plate to some extent, the valve plate does not displace in the radial direction, so there is no need to enlarge the valve housing.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings.

1 and 2 show the structure of a butterfly valve in a fully open state, and in the figures, 1 is an operating shaft inserted through a duct D. This operating shaft 1
The axis of the operating shaft 1 is located halfway in the longitudinal direction.
o ₁ and a large diameter eccentric shaft portion 2 centered on an eccentric axis o ₂ are integrally expanded.

The circumferential surface 2 of the eccentric shaft portion 2 of this operating shaft 1
A plate support shaft 3 to which a valve plate, which will be described later, is attached is fitted onto the top of the shaft _a . This plate support shaft 3 rotates synchronously with the eccentric shaft portion 2, that is, the operating shaft 1, by friction unless its rotation is restrained. When the rotation is restricted, relative rotation in which only the eccentric shaft portion 2 side rotates is possible, and at this time, the plate support shaft 3 is centered around the axis of the eccentric shaft portion 2.
o ₂ , it slides on its circumferential surface 2 _a and moves forward and backward in a direction orthogonal to the axis O ₁ of the operating shaft 1, as shown by the arrow in FIG. In addition, the eccentric shaft portion 2
The fitting surface of the plate support shaft 3 has a circumferential surface of the former.
A relative rotation prevention mechanism 4 is provided in a notch _4a provided in the notch 2a.The relative rotation prevention mechanism 4 has a structure in which _a protrusion _4b is fitted in the radial direction while being biased by a spring _4c from within the thickness of the latter.
In other words, this relative rotation prevention mechanism 4 has the role of ensuring synchronized rotation of the plate support shaft 3 and the eccentric shaft portion 2 (actuation shaft 1) and preventing rotation of the operation shaft 1 in the opposite direction. In the notch _4a of the eccentric shaft portion 2, a catch surface for the protrusion _4b is formed on one side, and an escape surface for the protrusion 4b is formed on the opposite side.

The outer circumferential end 5 is attached to one side of the plate support shaft 3 opposite to the relative rotation prevention mechanism 4.
A disk-shaped valve plate 5 having a sealing surface formed in a shape corresponding to the seat surface s of the duct D is attached to _a . This valve plate 5 is rotated together with the plate support shaft 3, but when the eccentric shaft portion 2 and the plate support shaft 3 cause the above-mentioned relative rotation, the plate support shaft 3 changes as the axis center o ₂ changes. Considering that the plate 5 is also displaced in the radial direction,
A slide mechanism 6 is employed to slidably couple the two in the radial direction of the valve plate 5. In this case, the slide mechanism 6 is specifically provided with a dovetail portion 6 _a at the mounting portion of the plate support shaft 3, and a radial dovetail groove 6 _b in the valve plate 5, and by engaging the two, the valve plate It is slidable only in the radial direction of the actuating shaft 1, and cannot be displaced relative to the direction perpendicular to the axis _o1 of the operating shaft 1. In order to adjust the mounting position of the valve plate 5 with respect to the plate support shaft 3, a positioning spring 7 is interposed at a portion of the valve plate 5 that faces each other in the radial direction.

In addition to these components, the valve plate 5 is provided with a rotation stopper 8 that stops further rotation when the valve plate 5 rotates to a position parallel to the seat surface s as shown in FIGS. 3 and 4. There is. In this case, the rotation stopper 8 is the valve plate 5.
a hit rod _8a extending rearward from the back side of one end;
When the valve plate 5 rotates to a predetermined position, the abutting rod 8 _a comes into contact with the protrusion 8 _b provided on the inner surface of the duct D to prevent the valve plate 5 from rotating.

The sealing material 9, such as an O-ring, is interposed between the outer peripheral end _5a of the valve plate 5 and the seat surface s.
It may be attached to either side.

Next, the operation of this butterfly valve is changed to the third one.
This will be explained with reference to FIG.

First, a case will be described in which the valve is brought from the fully open state shown in FIG. 1 to the fully closed state. In this case, the actuating shaft 1 is driven to rotate clockwise in the figure by a suitable driving means.
Then, with the action of the relative rotation prevention mechanism 4, the plate support shaft 3 on the eccentric shaft portion 2 rotates in sync with the eccentric shaft portion 2, and the valve plate 5 also rotates together with this. When the valve plate 5 rotates to a position near the seat surface s and parallel to the seat surface _s as shown in _FIG. Upon contact, the rotation stopper 8 works to prevent further rotation of the valve plate 5, and at the same time, the rotation of the plate support shaft 3 is restrained. Therefore, when the operating shaft 1 is further rotated clockwise from this state, the relative rotation prevention mechanism 4 is disengaged, and the operating shaft 1 then begins to rotate independently. However, since the plate support shaft 3 is fitted to the eccentric shaft portion 2 of the operating shaft 1, the plate support shaft 3 follows the movement of the axis o ₂ with respect to the relative rotation of the operating shaft 1 and performs the operation. The valve plate 5 attached to the plate support shaft ₃ is held in a position parallel to the seat surface s, as shown in FIG. 4. can be pressed against the sheet surface s.

On the other hand, the valve opening operation is performed by reversing the operating shaft 1. That is, when the operating shaft 1 is rotated counterclockwise from the state shown in FIG. 4, since the valve plate 5 is prevented from rotating by the seat surface s, first only the operating shaft 1 rotates, and as a result, the opposite rotation occurs. The mechanism causes the valve plate 5 to move back together with the plate support shaft 3 and move away from the seat surface s (approximately the third
(restored to the state shown in the figure). Then, when the valve plate 5 separates from the seat surface s, its rotation becomes free, so the plate support shaft 3 rotates in synchronization with the operating shaft 1, and together with this, the valve plate 5
As the valve rotates, the valve opening degree increases until it reaches the fully open position (the state shown in Figure 1).

As is clear from the above operation, according to the butterfly valve according to the present invention, when the butterfly valve is closed or opened, the valve plate 5 moves forward and backward in a posture parallel to the seat surface s, and does not come into contact with or separate from the seat surface s. It is something that can be done. Therefore, when the valve is closed, the sealing material 9 can be squeezed between the outer peripheral end _5a of the valve plate 5 and the seat surface s,
Vacuum seal performance is expressed in the most effective state.
In addition, since the inconvenience of the outer circumferential end 5 _a of the valve plate 5 sliding on the seat surface a during both opening and closing can be reliably avoided, uncertainties in operation due to friction can be eliminated, and at the same time, wear and tear on the sealing material 9 can be avoided. It will be reduced and its lifespan will be improved. Further, according to the butterfly valve according to the present invention, when the plate support shaft 3 moves forward while moving relative to the eccentric shaft portion 2 after its rotation is restrained, the change in the axial center position of the eccentric shaft portion 2 is The signal is transmitted to the plate support shaft 3, but since the plate support shaft 3 and the valve plate 5 can be slid relative to each other via the slide mechanism 6, from then on, the plate support shaft 3 will not move in the radial direction of the valve plate 5. Even if the valve plate 5 is displaced, the valve plate 5 will not be displaced in the radial direction from that position, and will only move forward toward the seat surface s. Therefore, in order to increase the forward and backward stroke of the valve plate 5 to some extent, the axis o ₁ of the operating shaft 1 is
Even if the eccentricity of the axis o2 of the eccentric shaft portion ₂ is set to a large value, the valve plate 5 does not displace in the radial direction, so there is no need to enlarge the valve housing (duct D), which is a special effect. become what is done.

It should be noted that the rotary stopper 8 necessary for the butterfly valve of the present invention is only one form shown in the embodiment, and various other forms can be used. Further, the relative rotation prevention mechanism 4 and slide mechanism 6 employed in the embodiment are not limited to those illustrated, and can be modified as appropriate. [Effects of the invention] According to the butterfly valve of the invention having the configuration and operation described in detail above, the valve plate approaches and separates by moving forward and backward in a posture parallel to the seat surface. The sealing state can be reliably achieved without contact failure, and the wear of the sealing material interposed on the sheet surface can be reduced. In addition, when the axial center position of the plate support shaft changes, the slide mechanism absorbs the motion component that attempts to displace the valve plate in the radial direction and does not transmit it to the valve plate, resulting in a larger valve housing. It is also possible to eliminate the problems caused by

[Brief explanation of the drawing]

FIGS. 1 and 2 show an embodiment of the present invention, with FIG. 1 being a partially cutaway sectional view, and FIG. 2 being a longitudinal sectional view of the main part thereof. 3 and 4 are sectional views for explaining the operation of the embodiment. FIG. 5 is a sectional view showing a conventional example. DESCRIPTION OF SYMBOLS 1... Operating shaft, 2... Eccentric shaft portion, 2 _a ... Circumferential surface, 3... Plate support shaft, 4... Relative rotation prevention mechanism, 5... Valve plate, 5 _a ... Outer peripheral end, 6
...Slide mechanism, 7...Positioning spring, 8...
... Rotating stopper, 8 _a ... Hitting rod, 8 _b ... Protrusion,
9...Sealing material, D...Duct, s...Seat surface.

Claims (1)

[Scope of utility model registration request] an operating shaft provided with an eccentric shaft portion; a plate support shaft that is fitted to the eccentric shaft portion of the operating shaft so as to rotate synchronously and is rotatable relative to the eccentric shaft portion only when the rotation is restrained;
It consists of a valve plate that is attached to the plate support shaft so as to be relatively slidable in the radial direction via a slide mechanism and rotates together with the plate support shaft, and a rotation stopper that stops the valve plate from rotating in a position parallel to the seat surface. The butterfly valve is characterized by: