JPS6210534Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a sealing device for a valve shaft bearing in a butterfly valve.

Conventionally, as this type of device, for example, the
There is one disclosed in Publication No. 33329.

In this system, a hollow cylindrical bearing member is fitted into the inner cavity of the bearing part of the valve box, and this bearing member supports the valve shaft, which has a valve body fixed to the inner part of the valve box, so as to be rotatable around its axis. An oblong recess such as a track circle or an ellipse into which the tip of the bearing member is inserted is provided on both end surfaces of the body in the direction of the valve shaft axis, and the tip of the bearing member is provided with a recess that is shaped like a track circle or an ellipse, and the tip of the bearing member is provided with a recess that is shaped like a track circle or an ellipse. An outward facing groove with a bottom is provided at a position facing both valve seats in the joint part, and an elastic sealing member is fitted into this groove, and when the valve is closed, the sealing member is inserted in the short diameter direction of the recessed part of the valve body. The valve body is positioned in close contact with the valve seat, the valve body valve seat, and the inner surface of the recess provided in the short diameter direction, thereby maintaining the sealing state when the valve is closed, and the recess of the valve body when the valve is opened. The above-mentioned close contact is released by positioning it in the major diameter direction.

However, the sealing member of the above-mentioned type usually has its outward sealing surface protruding from the outer circumferential surface of the bearing member when the valve is open. Since the sliding contact with the sealing surface starts quite early, in other words, the sliding contact by pressing the inner surface of the recess starts already from the time when the valve body passes the half-open state, so the sliding contact time becomes long. Therefore, there is a problem in that the sealing surface of the sealing member gradually wears out due to repeated opening and closing of the valve body, and the sealing function deteriorates, making it impossible to use the valve for a long period of time.

Therefore, the technical problem with this invention is to make the sealing surface of the sealing member protrude from the outer circumferential surface of the bearing member only when the valve is closed, thereby increasing the sliding contact time between the sealing surface of the sealing member and the inner surface of the recess of the valve body. The goal is to make it as short as possible.

The technical means taken to solve the above technical problem is to provide a circular recess concentric with the valve shaft on both end surfaces of the valve body in the direction of the valve shaft axis, and the tip of the bearing member is inserted into this circular recess. At the tip of this bearing member, a through groove is provided in a direction that intersects with the valve shaft at a position facing both valve seats at the joint between the valve body and the valve body when the valve is closed. The width of the opening on the side opposite to the valve stem is smaller than the width of the opposing end surfaces of both valve seats, and the edges on both sides of the opening do not come into contact with the edges on both sides of the opposing end surfaces of both valve seats when the valve is closed. A sealing member that is elastically displaceable in a direction intersecting the valve shaft is fitted into the through groove, and when the valve is closed, this sealing member is elastically compressed in the opposite side to the valve shaft to close both valve seats and the valve. The valve stem or the valve body is provided with a pressing member that is brought into close contact with the inner surface of the recessed portion of the body and released from the close contact when the valve is opened.

Next, to describe the operation, in the valve open state, the sealing member does not come into contact with the pressing member, and the outward sealing surface of the sealing member is in close contact with both the valve seats of the valve body and the valve body, and the inner surface of the recess of the valve body. It's liberated. When the valve shaft is rotated to close the valve, the pressing member will also rotate at the same time, and when the valve body is close to fully closed and positioned opposite the through groove, the pressing member will come into contact with the sealing member. The sealing member is elastically compressed on the side opposite to the valve shaft, and its sealing surface is projected from the outer peripheral surface of the bearing member and brought into close contact with both valve seats and the inner surface of the recess of the valve body. This completes the seal in the fully closed state. In addition, when the valve stem is rotated in the opposite direction to open the valve from a fully closed state, the pressing member also rotates in the opposite direction at the same time. The contact with the other parts is eliminated, the sealing member elastically restores its original state, and the sealing surface of the sealing member no longer protrudes from the outer peripheral surface of the bearing member, and the close contact with the inner surface of the recess of both valve seats and the valve body is immediately released. be done. As described above, the sliding contact between the sealing surface of the sealing member and the inner surface of the concave portion of the valve body is carried out only when the valve body is nearly fully closed, so that the time required for this is extremely short.

This invention produces the following unique effects.

Since the time of sliding contact between the sealing surface of the sealing member and the inner surface of the concave portion of the valve body is extremely short, wear on the sealing surface is significantly reduced, preventing deterioration of sealing function and enabling long-term use. The rotational resistance applied to the shaft is reduced, and the driving force can be kept to a smaller level. Furthermore, since the concave portion provided in the valve body according to this invention has a concentric circular shape and is not an oblong shape such as a track circle or an ellipse as in the conventional valve body, it is extremely easy to form the concave portion.

Examples of this invention will be described below.

In FIG. 1, 1 is a valve box, 2 and 2' are bearing parts provided at the upper and lower parts of the valve box 1, and 3 is a rotary valve shaft supported by the bearing parts 2 and 2'. A valve body 4 is fixed to the inner part of the valve box.
A valve body valve seat 6 provided on the outer circumferential surface of the valve body valve seat 5 provided on the inner circumferential surface of the valve box 1 slides into sliding contact with the valve seat 5 provided on the inner circumferential surface of the valve case 1 to open and close a flow path within the valve case 1. The bearing structure inside the bearing section 2' is almost the same as that inside the bearing section 2, except that it has a member 9 that supports the lower end surface of the valve shaft 3, so the explanation of the bearing structure inside the bearing section 2' will be as follows. In place of those in the bearing section 2 described below, similar parts will be omitted with the same reference numerals affixed with a dot.

As shown in enlarged views in FIGS. 2 and 3, the bearing structure inside the bearing part 2 has a structure on the upper end surface of the valve body 4 in the valve shaft direction, which has a diameter approximately the same as the bore 7 of the bearing part 2 and is concentric with the valve shaft 3. It has a circular recess 8. A hollow cylindrical bearing member 12 having an upper cover 10 and a bush 11 fitted in the inner cavity 7 of the bearing part 2 is fitted by inserting the lower end into the recess 8 and fixed with a bolt 13. At the lower end of the bearing member 12 facing the valve seat 5 of the valve body and the valve seat 6 of the valve body, a through groove 14 whose lower end is open and extends over the junction of the valve body 4 and the valve body 1 is provided.
It is installed in a direction that intersects with the The width w of the opening on the opposite side of the valve shaft 3 of the through groove 14 is equal to that of both valve seats 5 and 6.
is smaller than the width W of the opposing end surfaces of the through groove 14, and is formed so that both side edges of the opening do not come into contact with both side edges of the opposing end surfaces of the valve seats 5 and 6 when the valve is closed. The upper edge and the lower edge of the bush 11 are flush with each other. In the above description, the through groove 14 is shown as being open at the lower end, but the through groove may be open only in the direction intersecting the valve shaft 3 without opening at the lower end. A seal member 15 made of an elastic material such as rubber is fitted into the through groove 14 so as to be movable in a direction perpendicular to the valve shaft 3 and integrally has a seal receiver 16 on its inner surface. The outer surface of the seal member 15 is formed into an outward sealing surface 15a. Below the bush 11 facing the seal receiver 16, a vertical round bar-shaped cam member 17 as a pressing member of the seal member 15 is partially recessed in the outer peripheral surface of the cam ring 18, that is, the center of the cam member 17 is The axis is arranged and fixed slightly inside the outer peripheral surface of the cam ring 18. The cam ring 18 has an outer diameter slightly smaller than the inner diameter of the bearing member 12, and is fixed to the valve shaft 3 via a key 19.
In the above description, the cam ring 18 to which the cam member 17 is fixed is fixed to the valve shaft 3, but it may be fixed to the valve body 4 by any suitable means.

21 is a packing, 22 is a packing presser, 23,
24 and 25 each indicate a patch.

Next, the operation of the above embodiment will be explained.

1, 3 and the left half of FIG. 2 show the fully closed state of the valve. In this state, the cam members 17, 17' contact the seal receivers 16, 16', and this contact causes the seal members 15, 15' is displaced to the side opposite to the valve shaft 3 and compressed elastically, so that the seal surfaces 15a, 15a' of the seal members 15, 15' are in close contact with both valve seats 5, 6 and the inner surface of the recess 8 of the valve body 4. And keep the seal.

Next, to open the valve, the valve shaft 3 is rotated, for example, clockwise in FIG. 3. As a result, the cam members 17, 17' provided on the cam rings 18, 18' that rotate together with the valve shaft 3 and the valve body 4 also rotate in the same direction.
When the cam members 17, 17' are no longer positioned facing the through grooves 14, 14', they immediately release contact with the seal receivers 16, 16', so that the seal members 1
5, 15' are seal receivers 16, 16' through grooves 14,
14' to the cam ring 18 side and elastically restores the seal members 15, 15'.
The seal surfaces 15a, 15a' no longer protrude from the outer circumferential surface of the bearing member 12, releasing the tight seal with both valve seats 5, 6 and the inner surface of the recess 8 of the valve body 4, and maintaining the above state. 4 and the right half of FIG. 2 is reached.

To close the valve from the fully open state, rotate the valve shaft 3 counterclockwise. As a result, the cam member 17 also rotates in the same direction, reaching a state close to fully closed, and the through groove 14,
14', it comes into contact with the seal receivers 16, 16', and the seal members 15, 1
5' is elastically compressed to the side opposite to the valve shaft 3, the seal surfaces 15a, 15a' of the seal members 15, 15' protrude from the outer peripheral surface of the bearing member 12, and the valve seats 5,
6 and the inner surface of the recess 8 of the valve body 4 to reach a fully closed state. As mentioned above, the seal member 15,
The sealing surfaces 15a and 15a' of the cam member 15' are
7, 17', unless the valve body 4 is close to fully closed, it will not come into close contact with both valve seats 5, 6 and the inner surface of the recess 8 of the valve body 4; Since the sliding contact time is extremely short, the seal surface 15
a, 15a' wear is significantly reduced.

[Brief explanation of the drawing]

Fig. 1 is an overall partially longitudinal front view of an embodiment of this invention, and Fig. 2 is an enlarged longitudinal sectional front view of the same essential parts, with the left half showing the fully closed state and the right half showing the fully open state. . Figure 3 is a cross-sectional plan view of the fully closed state along the - line in Figure 2, excluding the valve box, and Figure 4 is the - line in Figure 2.
FIG. 2 is a cross-sectional plan view of the valve in a fully open state with the valve box removed along a line. 1... Valve box, 2, 2'... Bearing part, 3... Valve shaft, 4... Valve body, 5... Valve body valve seat, 6... Valve body valve seat, 7, 7'... Inside Cavity, 8, 8'... recess, 11,
11'... Bush, 12, 12'... Bearing member,
14, 14'... Through groove, 15, 15'... Seal member, 16, 16'... Seal receiver, 17, 17'...
...Cam member, 18, 18'...cam ring.

Claims (1)

[Scope of utility model registration request] A butterfly valve in which a hollow cylindrical bearing member is fitted into the inner cavity of the bearing part of the valve box, and the valve shaft, which has a valve body fixed to the inner part of the valve box, is supported rotatably around its axis by this bearing member. , circular recesses concentric with the valve shaft are provided on both end surfaces of the valve body in the valve shaft axis direction, and the tip of the bearing member is inserted into the circular recess, and the tip of the bearing member When the valve is closed, a through groove is provided in a direction that intersects the valve stem at a position facing both valve seats at the joint between the valve body and the valve body, and the width of the opening on the opposite side of the valve stem is equal to the width of both sides. The width of the opening is smaller than the width of the opposing end surfaces of the valve seats, and is formed so that both edges of the opening do not come into contact with the edges of the opposing end surfaces of both valve seats when the valve is closed. A sealing member that can be elastically displaced in the direction of the valve is fitted, and when the valve is closed, this sealing member is elastically compressed to the opposite side of the valve shaft to tightly contact both valve seats and the inner surface of the recess of the valve body, and when the valve is opened, A sealing device for a valve shaft bearing portion in a butterfly valve, characterized in that a pressing member for releasing the close contact is provided on the valve shaft or the valve body.