JPH094644A - Coupling for valve rod - Google Patents

Abstract

PURPOSE: To prevent an end surface part of a coupling member for a valve rod from causing a crack and the like. CONSTITUTION: A reaming hole 3r fit in a body part 2a of a valve rod 2 is formed at the inserting side of a tapped hole 3a of the coupling member 3 and the body part 2a of the valve rod 2 is fit in the reaming hole 3r of this coupling member 3 to connect them. Two-pieces divided parts 31 and 32 are formed so as to form a gap 3d between engaging surfaces of the two pieces divided parts of this coupling member 3 when the two pieces divided parts 31 and 32 of the coupling member 3 are clamped by a clamping bolt/nut 7 and 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve stem joint for transmitting the movement of a drive unit (actuator) for opening and closing a large valve used in various plants such as steam plants and chemical plants to a valve body. Is.

[0002]

2. Description of the Related Art FIG. 2 shows a conventional valve stem joint (A).
Is an overall longitudinal sectional view, (B) is an enlarged view of the joint portion, and (C) is a side view thereof. The valve rod 2 which is integral with the valve body 5 is axially movably supported by the bush 6. A drive rod 4 of a drive unit (actuator) 1 that drives the valve to open and close and a valve rod 2 are connected by a joint member 3. The joint member 3 is shown in FIG.
As shown in (B) and (C), the halved parts 31, 32
Is a structure in which is tightened with tightening bolts and nuts 7 and 8. As shown in FIG. 2B, the left side portion of the joint member 3 in the drawing has a shape that fits and engages with the constricted portion 4c of the drive rod 4, and the right side portion of the joint member 3 in the drawing is A screw hole 3s that is screwed into a male screw portion 2s formed at the rear end of the valve rod 2 is formed.

As shown in FIG. 2, a conventional valve stem joint is as follows.
The portion of the joint member 3 on the left side of the drawing is the constricted portion 4c of the drive rod 4.
, And the two parts 31 and 32 are firmly fastened together by the tightening bolts 7 to be integrated, and then the male screw part 2s of the valve rod 2 is screwed into the screw hole 3s on the right side of the drawing of the joint member 3. And connect. When the drive rod 4 is moved in the axial direction by the driving force of the drive unit 1, the valve rod 2 connected via the joint member 3 is guided and supported by the bush 6 to move in the axial direction, and the valve body 5 is opened. Stops or allows the flow of fluid by opening and closing the valve by moving it in and out of the seat. It should be noted that in consideration of wear of the valve seat and the like due to use, allowance should be provided so that the amount of screwing the male screw portion 2s of the valve rod 2 into the screw hole 3s of the joint member 3 can be adjusted. There is.

[0004]

The joint of the conventional valve rod is as described above, but the fluid flowing in the valve hits the valve body 5 and a vortex is generated, so that the valve body 5 and the valve rod 2 are vibrated. However, since there is a gap between the bush 6 supporting this and the valve rod 2, this vibration also extends to the joint between the valve rod 2 and the joint member 3, and the joint member end surface portion K of the valve rod 2 is made. Is a sudden change in shape, and the valve member 2 is regarded as a beam, and the joint member end face portion K
If we consider the part of the beam as the fixed support part of the beam, the joint member end face part K
The portion marked with is the portion where the bending stress is maximized, and this portion is the male screw portion 2s of the valve rod 2, which is a portion that is defective against the stress due to the unevenness of the shape of the screw. A large concentrated stress is generated in the bending stress associated with the vibration of the rod 2, and a crack may be generated in the portion, resulting in breakage.

The present invention has been made in order to solve the above problems, and an object thereof is to obtain a valve rod joint in which a stress generated in a connecting portion between the valve rod 2 and the joint member 3 is small and cracks or breakage do not occur. And

[0006]

A valve rod joint according to the present invention has a reamed finish hole formed on the insertion side of a threaded hole of a joint member so as to be fitted to the main body portion of the valve rod, and the reamed finish of the joint member. The main body of the valve rod is fitted into the hole and connected. Further, a reamer finishing hole that fits into the main body portion of the valve rod is formed on the insertion side of the screw hole of the split joint member, and the main body portion of the valve rod is fitted into the reamer finishing hole of the joint member to form the joint member. The two-part component of the joint member is formed so that when the two-part component is connected by tightening it with a tightening bolt, a gap remains between the two mating surfaces of the joint member.

[0007]

Since the valve rod joint according to the present invention has a structure in which the main body of the valve rod is inserted into and connected to the reamer finishing hole formed on the insertion side of the screw hole of the joint member, the end face of the joint member is The point at which the bending stress of the valve rod is maximum is
Since it is the main part of the valve rod, which has a large diameter and has no irregularities in the shape of a screw, the bending stress is small and there is no defect against the stress. This prevents cracks or breakage from occurring in this portion. If the body of the valve rod is fitted into the reamer finishing hole of the joint member and the two-piece component of this joint member is tightened with the tightening bolt, a gap is left between the two mating surfaces of this joint member. When tightened with a tightening bolt, the split joint member sandwiches the valve rod and is integrally connected by the tightening force of the tightening bolt. Therefore, the generation of cracks or the like at the joint is prevented without the occurrence of secondary vibration or stress.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a valve stem joint according to an embodiment of the present invention, (A) is an overall longitudinal sectional view, and (B) is an enlarged view of the joint portion.
(C) is the side view. In FIG. 1, 1 is a drive unit (actuator) such as a hydraulic or pneumatic cylinder, 4 is a drive rod (actuator rod or piston rod) of the drive unit 1, and the drive force given by the drive unit 1 is used in the axial direction. Move (left and right in the figure). Reference numeral 2 is a valve rod, and the valve rod 2 is integrally or integrally connected to the valve body 5. Reference numeral 3 denotes a joint member (coupling) which connects the drive rod 4 and the valve rod 2 to transmit the driving force. Reference numeral 6 denotes a bush, which is provided on the valve housing and supports the valve rod 2 movably in the axial direction. Reference numeral 7 is a tightening bolt, and 8 is a tightening nut. As shown in FIG. 1 (C), the split parts 31 and 32 of the joint member 3 are fastened and integrated. The drive unit (actuator) 1 may use electric power.

As shown in FIGS. 1B and 1C, a constricted portion 4c is formed at the tip of the drive rod 4. Also,
The joint member 3 is composed of two parts 31 and 32, and when the two parts 31 and 32 are combined, the joint member 3 shown in FIG.
The left side portion of (B) is formed in a shape that fits into the constricted portion 4c of the drive rod 4. Tightening bolts and nuts 7, 8
To remove the halved parts 31 and 32, and drive rod 4
The constricted portion 4c of the joint member 3 is gripped by the left portion of the joint member 3 in FIG.
It is formed so that the drive rod 4 and the joint member 3 can be connected to each other by fastening through the bolt hole of the joint member 3.

As shown in FIGS. 1B and 1C, the valve rod 2
A male screw portion 2s is formed at the rear end portion. Further, in a state where the joint member 3 including the split parts 31 and 32 is fastened with the tightening bolts and nuts 7 and 8, the male screw portion 2s of the valve rod 2 is screwed to the right side portion of FIG. Screw hole 3s
Is formed, and the valve rod 2 is provided on the right side portion of the screw hole 3s in the figure.
A reamer finishing hole 3r that fits into the main body 2a is formed. Male screw part 2s of valve rod 2 and screw hole 3 of joint member 3
The axial length to be screwed with s is set to be equal to or longer than the length required for transmitting the axial force from the drive unit 1. Reamed hole 3
The axial length of r is 1 / thickness of the thickness of the joint member 3 at this portion.
It is about 3. The screw hole 3s, the reamed hole 3r, and the valve rod 2 of the joint member 3 are adjusted so that the axial length can be adjusted against wear of the valve seat and the like due to use.
It is necessary that the length of the male screw portion 2s of 2 is a sufficient length.

In FIG. 1, in order to manufacture the joint member 3 having the above-described shape, which is composed of the two split parts 31 and 32, when forming so that there is no gap between the mating surfaces of the two split parts 31 and 32, a tightening bolt is used.・ Machining with the nuts 7 and 8 fastening the split parts 31 and 32
It is sufficient to form s and the reamer finishing hole 3r. FIG.
When forming so as to have a gap 3d between the mating surfaces as shown in (C), after making the halved parts 31 and 32 as described above, the mating surface is abraded as well as drilled. Prior to the above, with the thin plate having the thickness of the mating surface gap 3d sandwiched over the entire mating surface to firmly fasten the split parts 31 and 32, the screw hole 3s and the reaming finishing hole 3r including the sandwiched thin plate are formed. There is also a method of removing the sandwiched thin plate after forming it by machining.

Next, the operation and action of the embodiment shown in FIG. 1 will be described. First, in order to connect the valve rod 2 and the drive rod 4 via the joint member 3, the tightening bolts and nuts 7 and 8 of the joint member 3 are removed and the split parts 31 and 32 are opened to make the joint member 3 1 (B) on the left side, the constricted portion 4c of the drive rod 4 is gripped, and then the tightening bolt 7 is passed through the bolt hole and the tightening nut 8 is screwed in to be fastened. The member 3 can be connected. Next, the fastening bolt 7 is fastened as it is in the joint member 3 having a shape without the mating surface gap 3d. In the joint member 3 having the mating face gap 3d, a thin plate having the thickness of the mating face gap 3d is sandwiched and fastened with the tightening bolts and nuts 7 and 8 so that the male screw portion 2s of the valve rod 2 is screwed to the joint member 3. The valve body 2a of the valve rod 2 is screwed into the hole 3s, and the main body 2a of the valve rod 2 is screwed into the reamer finishing hole 3r to the extent shown in the drawing. Next, the mating surface gap 3
Remove the thin plate sandwiched in d, and tighten the bolts and nuts 7, 8
If is further tightened, the inner surface of the reamer finishing hole 3r of the split parts 31 and 32 of the joint member 3 is crimped to the main body portion 2a of the valve rod 2 so that the joint member 3 and the valve rod 2 are integrated. With this, the valve rod 2 and the drive rod 4 are connected via the joint member 3. The dimensions of each member are formed so that the valve body 5 can be appropriately opened and closed by the drive unit 1 in the state of being connected as described above.

In FIG. 1A, if the drive unit 1 and the drive rod 4 are driven in the axial direction (left and right direction in the figure) by hydraulic pressure, air pressure or electric force, the valve rod 2 is pushed through the joint member 3 and the bush 6 is pushed. Is guided and moved in the axial direction to move the valve body 5 in the axial direction to bring the valve body 5 into and out of contact with the valve seat, thereby closing / opening the valve to prevent fluid passing through the valve. Stop the flow
Distribute.

In FIG. 1 (A), the fluid flowing in the valve hits the valve body 5 to generate a vortex, and the valve body 5 and the valve rod 2
However, since there is a gap between the bush 6 supporting this and the valve rod 2, the vibration also extends to the joint between the valve rod 2 and the joint member 3, and the portion of the joint member end surface portion K. Is a sudden change in shape, and assuming that the valve rod 2 is a beam and the joint member end surface portion K is a fixed support portion of the beam, the joint member end surface portion K is a portion where the bending stress becomes maximum. In the conventional valve stem joint shown in FIG. 2, the joint member end surface portion K becomes the male screw portion 2s of the valve stem 2, and as described above, a large concentration of stress is generated due to the vibration of the valve stem 2. Although there was a case where a crack was generated in the portion and it was broken, in the joint of the valve rod shown in FIG. 1, the portion of the joint member end surface portion K was fit into the reamed finish hole 3r. Then, since this portion is the portion of the main body portion 2a, there is no unevenness in the shape of a screw and the diameter is large, the bending stress is small and there is no defect against the stress. Therefore, cracks or the like are prevented from occurring in the valve rod 2 even at the location of the joint member end surface portion K which is the maximum stress portion. The axial force is transmitted by the male screw portion 2s, and the bending stress due to vibration is taken up by the body portion 2a.

Also, the split parts 31, 3 of the joint member 3
If 2 is tightened with the tightening bolts / nuts 7 and 8 so that a gap 3d is left between the two mating surfaces of the joint member 3, the tightening bolts / nuts 7 and 8 will force Since the split joint member 3 and the valve rod 2 are strongly joined together without any risk of rattling, a secondary vibration or stress generated due to rattling does not occur, and cracks or the like occur at the joint. The occurrence is further reliably prevented.

The reamed hole means a precise process such as reaming, and is not limited to reaming. Further, in the embodiment shown in FIG. 1, the joint member 3 is divided into two parts, that is, the parts 31 and 32, but in FIG. 1B, the part connected to the valve rod 2 on the right side is not divided. Only the portion of the left side portion connected to the drive rod 4 is divided so as to be opened, and the constricted portion 4c of the drive rod 4 is divided.
Tightening bolts and nuts 7,
The structure may be such that it is fastened at 8 and connected.

[0017]

As described above, according to the present invention, the reamer finishing hole that fits the main body of the valve rod is formed on the insertion side of the screw hole of the joint member, and the main body of the valve rod is formed in this reamer finishing hole. Since the parts were connected so that they would fit in, the end face of the joint member, where large stress is applied to the valve stem due to the vibration of the valve disc, becomes the main body of the valve stem, which has a large diameter and causes stress-like defects such as screws. Since it is not present, cracks and breakage are prevented from occurring in this part. Further, by forming a gap between the split mating surfaces of the joint member, the joint member and the valve rod are tightly integrated, and the occurrence of secondary damage is prevented.

[Brief description of drawings]

FIG. 1 shows a valve stem joint according to an embodiment of the present invention,
(A) is an overall longitudinal sectional view, (B) is an enlarged view of the joint part,
(C) is the side view.

2A and 2B show a conventional valve rod joint, in which FIG. 2A is an overall longitudinal sectional view, FIG. 2B is an enlarged view of the joint portion, and FIG.

[Explanation of symbols]

1: Drive part, 2: Valve rod, 2a: Main body part, 2s: Male screw part, 3: Joint member, 31, 32: Divided parts, 3
r: Reamed finish hole, 3s: Screw hole, 3d: Mating surface gap, 4: Drive rod, 4c: Constricted portion, 5: Valve body,
6: Bush, 7, 8: Tightening bolts / nuts, K: End surface of joint member.

Claims (2)

[Claims] 1. A valve rod joint in which a male screw portion formed at an end portion of the valve rod is screwed into a screw hole of a joint member to be connected,
A reamer finishing hole that fits into the main body portion of the valve rod is formed on the insertion side of the screw hole of the joint member, and the main body portion of the valve rod is fitted and connected to the reamer finishing hole of the joint member. And the valve stem joint. 2. A valve rod joint in which a male screw portion formed at an end portion of the valve rod is screwed into a screw hole of a split joint member to be connected, and the valve rod is provided on an insertion side of the screw hole of the joint member. When a reamed hole to be fitted to the main body of the joint is formed, the main body of the valve rod is inserted into the reamed hole of the joint member, and the split part of the joint member is tightened with a tightening bolt to connect the joint. A joint for a valve rod, characterized in that the split member of the joint member is formed so that a gap is left between the two mating surfaces of the member.