JP3067647B2 - Valve shaft sealing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shaft sealing device between a valve stem for supporting a valve body and a main body (valve main body) in various valves such as a butterfly valve.

[0002]

2. Description of the Related Art Conventionally, in a valve of a type in which a driving means for a valve body is located outside a main body, such as a butterfly valve, a valve stem for supporting the valve extends outside the main body. To prevent leakage of fluid from between the rod and the main body, or to prevent intrusion of fluid, rainwater, dust, etc. from the outside, a shaft sealing device that seals the gap between the valve rod and the main body is provided. Have been.

[0003] The most common conventional structure of the above-mentioned shaft sealing device is such that a step is formed near a valve stem fitting portion of a flange integrally formed at an end of a main valve stem, and asbestos is formed in the step. The gasket such as is fitted and closely attached to the outer peripheral surface of the valve stem, but according to the type of the gasket, the number of steps to be inserted and the method of inserting, the rotational torque of the valve stem is not constant, and There was a problem that the size and shape became large.

In order to address the above problem, as shown in FIG. 5, a groove 3 into which an O-ring 2 surrounding a valve stem 1 is inserted.
Is formed on the inner peripheral wall of the valve stem 4, but it is extremely difficult to form a groove in the inner peripheral wall of the valve stem 4 in a small-diameter valve. On the other hand, a groove was formed on the outer circumference of the valve stem,
An O-ring has been proposed to be fitted into the groove so as to be in close contact with the inner peripheral surface of the valve stem. However, the formation of the groove partially reduces the diameter of the valve stem, and therefore, the strength, especially the torsional strength, is increased. However, there is a problem that the temperature is reduced.

In order to address these problems, the applicant of the present invention has proposed a valve as shown in FIG. Shaft hole 5a in rod 1
The elastic sealing plate 5
Is disposed, and a separate pressing plate 6 is placed on the upper surface of the elastic sealing plate 5 by passing the valve stem 1 through the shaft hole 6a.
The two are integrally attached by a screw 7, an annular projection 6 b is formed on the lower surface of the holding plate 6, and an annular groove 5 b fitted with the annular projection 6 b is provided on the elastic sealing plate 5. A proposal has been made in which the inner plate portion 6c presses the upper surface of the inner portion of the elastic sealing plate 5 so that the compression ratio between the valve stem 1 and the shaft sealing portion 8 is kept constant. In the drawing, reference numeral 5c denotes a projection provided on the lower surface for stably positioning the elastic sealing plate 5 in the recess 4a of the valve stem 4, and is fitted into the hole 4b of the recess 4a. (Actual fairness 8
-10716 publication).

[0006]

According to the above-mentioned application of the present applicant (FIG. 4), the amount of compression of the elastic sealing plate 5 is reduced by the tightening of the screw 7 for fixing the elastic sealing plate 5 with the holding plate 6. It became unstable, and there were problems in the rotation torque of the valve stem 1, durability and lubricity. In addition, since the shaft sealing portion (seal portion) 8 is single, it is difficult to cope with wear and damage, and at the same time, there is a problem that replacement cost of the elastic sealing plate 5 becomes expensive.

The present invention solves the problems of the above-mentioned prior art, particularly the shaft sealing device according to the earlier proposal of the present applicant, and is arranged on the upper part of the valve stem and penetrated by the valve stem. An object of the present invention is to provide a valve shaft sealing device which has little influence on the rotation torque of a valve stem due to an elastic sealing material, has durability and lubricity, and has excellent sealing performance.

[0008]

In order to solve the above-mentioned problems, a means adopted in the present invention is to insert a shaft hole into a valve stem extending out of a valve stem cylinder of a main body, and to form a flange of the valve stem cylinder. A valve stem guide arranged in the lower part of the step formed in the shaft hole of the shaft, an elastic sealing material arranged in the middle part of the step of the flange while similarly inserting the shaft hole into the valve stem, While inserting the shaft hole through the rod, with the holding plate arranged on the upper stage of the step of the flange,
The elastic sealing member is formed of separate members so as to be in contact with each other, and protrudes from upper and lower contact surfaces of the elastic sealing material so as to face the lower surface of the holding plate and the upper surface of the valve stem guide in the valve axis direction. An annular groove is provided to be fitted with the provided annular projection, and an inner diameter portion which slides on the valve stem of the elastic sealing material and an outer diameter portion which is fitted to the inner surface of the step formed on the flange are respectively provided. In addition, an annular holding groove for lubricant is formed in the inner diameter portion.

Further, a valve stem guide which is in contact with a lower portion of a step portion formed on the flange of the valve stem is formed in an L-shaped cross section, and its end prevents the valve stem from projecting outward. It is characterized in that it also serves as a thrust and a radial bearing.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the embodiments shown in the drawings. FIG. 1 is a cross-sectional view of a main part in which a lower part of a central butterfly valve according to an embodiment of the present invention is omitted.

In the figure, a main body (valve main body) 10 has a valve stem 11 above, a flange 12 integrally formed on the upper surface thereof, and an elastic seat ring 13 on the inner peripheral surface of the main body 10. The valve body 1 is fitted so that it comes into contact with and separates from its inner surface.
4 is pivotally supported by a valve stem 15, and the valve body 14 is
Is rotated to control opening and closing of the fluid passage.

In the present embodiment, the valve element 14 and the valve stem 15 are integrated by a connecting portion 16 formed by joining a square hole and a square shaft. Therefore, the valve stem 15 is inserted into the square hole from above. Therefore, as a retaining means, a roll pin (stop pin) 17 is inserted into an upper portion of the valve stem 15 so as to be engaged with a lower end of a valve stem guide 18 described later. I try to play a role.

A lower hole 12a and a middle hole 12a are provided in a shaft hole through which the valve stem 15 penetrates the flange 12 at the upper end of the valve shaft cylinder 11.
b, a step portion 12A consisting of an upper step 12c is formed,
A valve stem guide 18 made of metal or non-metal such as stainless steel, brass, hard resin, or the like having an L-shaped cross section through which the valve stem 15 penetrates at the center, is engaged with the lower part 12a. In the middle stage 12b, which corresponds to the intermediate cylindrical portion between the lower stage 12a and the upper stage 12c, an elastic sealing material 19 through which the valve stem 15 is passed at the center is brought into contact with the upper surface of the valve stem guide 18. In the upper stage 12c,
The plate-shaped valve stem guide 18 through which the valve stem 15 passes through the center
A pressing plate 20 made of the same metal or non-metal as described above is fitted so as to contact the upper surface of the elastic sealing material 19, and these three members 18 to 20 fitted into the three steps 12a to 12c respectively are The fixing plate 20 is fixed with a certain pressing force by tightening a bolt 21 for fixing the holding plate 20 to the flange 12.

The upper and lower abutting surfaces of the elastic sealing member 19 have annular projections 2 projecting from the lower surface of the holding plate 20 and the upper surface of the valve stem guide 18 so as to oppose each other in the valve axis direction.
There are provided annular grooves d and e (FIG. 3), which are fitted with Oa and 18a, respectively.

FIG. 3 is an enlarged view of part A of FIG.
In (a), B indicates the central axis (valve axis) of the valve stem 15 and C
Indicates an outer diameter portion of the valve stem 15, and an a portion is a sliding interference fixed to the valve stem outer diameter portion C, and is overlapped with the valve stem 15 in FIG. . The section C is an interference for fixing fixed to the main body flange 12, and is similarly shown overlapping with the imaginary line. In addition, the part B indicates an interference for fixing in the upward and downward directions, and is similarly shown overlapping with the imaginary line.

The interferences (compression allowances) of the above-mentioned (a), (b) and (c) have different shapes, dimensions and configurations because of different purposes for sliding and fixing. That is, if the interference of the inner diameter portion is too large, the sealing property is large, but there is a problem in the abrasion resistance. Similarly, if too small, the opposite is true. Therefore, it is the introduction groove that takes into consideration these problems into the annular holding groove in which the lubricant is sealed. Examples of the lubricant include grease and silicon-based lubricant. Before assembly, these lubricants expand the inside diameter up and down and enclose them in the holding grooves so that the valve stem 1
Due to the pumping action accompanying the slight twisting phenomenon caused by the rotation of 5, the lip corresponding to the portion A of the elastic sealing material 19 is given an appropriate lubricating property, and abrasion resistance, durability and smooth rotation torque appear. can do.

Examples of the material of the elastic sealing material 19 include a nitrile type (NBR) and an ethylene / propylene type (EPD).
M), Fluorine (FKM), Fluororesin (PTFE)
Etc.

The lower surface of the holding plate 20 and the valve stem guide 18
The annular grooves d and e of the elastic sealing material 19 fitted to the annular projections 20a and 18a respectively formed on the upper surface of the valve are strongly pressed by the upper and lower pressing plates 20 and the annular projections 20a and 18a of the valve stem guide 18. Rather, by proper pressing, it acts as a blow-by, that is, internal pressure, high-speed rotation, and the like, to prevent leakage to the gap between the upper and lower pressing plates 20 and the valve stem guide 18.

FIGS. 3 (b), 3 (c) and 3 (d) show another embodiment similar to FIG. 3 (a), in which the same symbols as those shown in FIG. 3 (a) are used. The same or similar parts shall be indicated. That is, in the embodiment of FIG. 6B, the interference for fixing B is omitted, and the interference for the sliding portion A and the interference for the fixed portion C are both formed in a circular shape. In the embodiment of ()), the interference of the sliding portion (a) is in the form of a lip, and the interference of the fixed portion (c) is in the shape of a sphere.
A plurality of (two in the figure) chevrons are provided for the sliding part interference along the valve stem peripheral surface, and the fixed part interference C is formed in a spherical shape, but the combination of these or other shapes is also the same. It is possible to apply to.

In FIGS. 1 and 2, 15a is an implantation key, 22 is a gap, 22a is a no-machined surface, and 23 is a lower bearing.

With the above construction, the elastic sealing member 19, the valve stem guide 18, and the holding plate 20 are formed of separate members, respectively, so that when the elastic sealing member 19 is inserted into the valve stem 15, In addition, there is a degree of freedom without restricting the elastic deformation of the inner diameter sliding portion and the outer diameter fixing portion, and the assembling can be easily performed without wear due to insertion. Further, after assembly and insertion, the annular projections 18a of the valve stem guide 18 and the holding plate 20,
The sliding portion and the fixed portion of the inner and outer diameter portions are fixedly supported in a predetermined shape by 20a. That is, the annular protrusions 18 a and 20 a of the valve stem guide 18 and the holding plate 20 are
The annular grooves E and D are backed up (pressed) to ensure a sealing action and prevent blow-by, that is, leakage (deformation) of the lip of the seal portion due to fluid pressure.

In order to keep the elastic sealing material 19 in a fixed state, the stepped portion 1 of the shaft hole of the flange 12 of the valve stem 11 is formed.
Since the depths a to c of 2A and the thicknesses of the valve stem guide 18 and the holding plate 20 are regulated, the pressing force against the elastic sealing material 19 is constant regardless of the degree of tightening of the holding plate 20 by the bolt 21. The lubricating action accompanying the sliding of the inner diameter portion of the elastic sealing material 19 is achieved by forming the annular holding groove for the lubricant, and the lubricant filled in the holding groove by the rotation of the valve rod 15. Then, a pumping action occurs due to a slight twisting phenomenon of the lip of the seal portion, and the lubricant is delivered to the portion.

Further, by providing a plurality of lips in the seal portion, it is possible to prevent the internal and external pressures from flowing out and in. At the same time, it performs a dust sealing action against external pressure (dust). In addition, by changing the interference allowances of the inner diameter portion and the outer diameter portion, the respective sealing effects can be reliably maintained.

In the above embodiment, the structure of the center type butterfly valve has been described. However, the valve stem extends to the outside through the main body, and other shafts requiring a shaft seal between the valve stem and the main body are required. Needless to say, the present invention can be similarly applied to a valve, for example, a rotary valve such as a ball valve.

[0025]

As described above, according to the present invention,
While inserting the shaft hole into the valve stem extending out of the valve stem cylinder of the main body, the valve stem guide disposed in the lower part of the step formed in the shaft hole portion of the flange of the valve stem cylinder, similarly to the valve stem. While inserting the shaft hole,
The elastic sealing material arranged in the middle of the step portion of the flange and the presser plate arranged in the upper stage of the step portion of the flange while the shaft hole is also inserted through the valve stem are separately contacted with each other. An annular projection formed of a body member and fitted to upper and lower contact surfaces of the elastic sealing material so as to protrude from the lower surface of the holding plate and the upper surface of the valve stem guide so as to face each other in the valve axis direction. The following effects can be obtained by providing the annular grooves that match.

(I) Since the elastic sealing material, the valve stem guide, and the holding plate are each formed of separate members, when the elastic sealing material is inserted into the valve stem, the inner diameter sliding portion and the outer diameter fixing portion are formed. It is easy to assemble without restricting the elastic deformation, having a degree of freedom, and without abrasion due to insertion.

(Ii) The elastic sealing material is pressed at a constant pressure in the valve shaft direction by a holding plate whose displacement is regulated by each step formed in the shaft hole of the flange of the valve shaft cylinder and the valve stem guide. In addition, since the sliding portion and the fixed portion of the inner and outer diameter portions are both fixed and supported in a predetermined shape by fitting the annular protrusion and the annular groove portion, the sealing action is ensured, and the sealing portion is formed by the fluid pressure. It is possible to prevent blow-by (blow-by).

Further, a clearance is provided in each of an inner diameter portion which slides on the valve stem of the elastic sealing material and an outer diameter portion which is fitted to the inner surface of the step formed on the flange. The following effects can be obtained by forming the holding grooves.

(I) Due to the rotation of the valve stem, the lubricant filled in the annular holding groove is subjected to a pumping action caused by a slight twist phenomenon of the seal portion (tightening margin) of the sliding portion of the inner diameter portion of the elastic sealing material. In addition, the lubrication function of the seal portion is improved so that the abrasion of the elastic sealing member is prevented, and the valve can be opened and closed with a constant rotational torque with an appropriate lubrication function.

(Ii) By changing the interference between the inner diameter portion and the outer diameter portion of the sealing portion of the elastic sealing material, the respective sealing effects can be more reliably maintained.

The valve stem guide, which is in contact with the lower part of the step formed on the flange of the valve stem, is formed in an L-shaped cross section, so that the end prevents the valve stem from projecting outward. , And can also serve as thrust and radial bearings.

[Brief description of the drawings]

FIG. 1 is a sectional view of a valve shaft sealing device showing one embodiment (example) of the present invention.

FIG. 2 is a sectional view showing a main part of FIG.

3 (a) to 3 (d) are enlarged views of a portion A in FIG. 2 and show different embodiments of an elastic sealing material.

4A and 4B show a conventional example, in which FIG. 4A is a partially sectional perspective view showing an assembled state, and FIG. 4B is a partially enlarged sectional view before assembling.

FIG. 5 is another conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Main body 11 Valve stem 12 Flange 12a Lower part 12b Middle part 12c Upper part 12A Step part 13 Elastic seat ring 14 Valve element 15 Valve rod 16 Connecting part 17 Roll pin 18 Valve rod guide 19 Elastic sealing material 20 Press plate 21 Bolt 22 Void part 23 Lower part Bearing part 24 O-ring a Thickness of valve stem guide at stepped part b Thickness of elastic sealing material at stepped part c Thickness of presser plate at stepped part a Tightening allowance at inner diameter part To the annular groove where the projection fits To the annular groove where the projection fits To the annular holding groove (lubricant)

Continuation of the front page (56) References JP-A 5-10870 (JP, U) JP-A 57-59277 (JP, U) JP-A 54-151829 (JP, U) JP-A 55-181065 (JP) , U) Shokai Sho 55-68752 (JP, U) Japanese Patent Publication No.8-10716 (JP, B2) Shoko 52-25710 (JP, Y2) Shoko 1-8781 (JP, Y2) Shoji Shoko 40-7893 (JP, Y1) Jiko 36-22658 (JP, Y1) (58) Fields investigated (Int. Cl. ⁷ , DB name) F16K 1/00-1/228 F16K 41/00-41 / 18 F16J 15/32

Claims (2)

(57) [Claims] 1. A valve stem guide disposed at a lower portion of a step formed in a shaft hole of a flange of a valve stem while inserting a stem into a valve stem extending out of a valve stem of a main body. Similarly, an elastic sealing material disposed in the middle of the step portion of the flange while the shaft hole is inserted through the valve stem, and a presser disposed in the upper stage of the step portion of the flange while similarly inserting the shaft hole into the valve stem. The plate and the plate are constituted by separate members so as to contact each other, and the upper and lower contact surfaces of the elastic sealing material are opposed to the lower surface of the holding plate and the upper surface of the valve stem guide, respectively, in the valve axis direction. An annular groove that fits with the annular projection that is provided so as to protrude, and an inner diameter that slides on the valve stem of the elastic sealing material and an outer diameter that fits with the inner surface of the step formed on the flange. Each part is provided with a closing margin, and further, an annular holding groove for lubricant is formed in the inner diameter part. Valve sealing device. 2. A valve stem guide, which is in contact with a lower portion of a step portion formed on a flange of a valve stem, is formed in an L-shaped cross section. And a radial bearing.
The valve sealing device of the above-mentioned valve.