JPH07224945A - Shaft seal device - Google Patents

Abstract

PURPOSE:To prevent generation of any gap by good following-adaptation of a packing to displacement even if shaft vibration, etc., are generated on a rotary shaft, and prevent leakage of fluid for a long period. CONSTITUTION:A movable packing 4 whose inner circumferential surface is brought in contact with a rotary shaft 2 and whose outer circumferential surface has a gap toward a packing box 1, is inserted instead of a part of a gland packing 3 or the total thereof, a sliding surface ring 6 having small surface friction resistance is interposed between the axial direction at both surfaces of the movable packing 4, and an elastic O-ring 5 having large elastic displacement performance is interposed in a gap between the movable packing 4 and the packing box 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gland packing type shaft sealing device for preventing fluid from leaking from a rotary shaft penetrating portion of a rotary fluid machine, and to prevent leakage due to shaft runout and shaft vibration of the rotary shaft. It relates to means for preventing.

[0002]

2. Description of the Related Art FIG. 3 shows a conventional shaft seal device. A plurality of annular gland packings 3 are stacked in the axial direction and inserted into a space formed between the packing box 1 and the rotary shaft 2, and the packing presser 7 is pushed from above the gland packing 3 to press the packing presser. If the gland packing 3 is axially pressed by tightening the presser bolt 8 hung on the gland 7, the gland packing 3 spreads in the inner and outer diameter directions at a certain ratio (Poisson's rate) according to the amount of compression in the axial direction. Thus, the gland packing 3 is pressed against the inner peripheral surface of the packing box 1 and the outer peripheral surface of the rotating shaft 2 to close the gap, and the fluid leakage is prevented. As the gland packing 3, a braided packing made of asbestos, cotton yarn, or the like is used, and since it has elasticity and plasticity to some extent, the gland packing 3 is deformed following a slight displacement of the rotary shaft 2 to prevent leakage. When the amount of leakage increases, the holding bolt 8 can be tightened again to restore the sealing ability.

[0003]

The conventional shaft sealing device is as described above, but as shown in FIG. 3, when the amplitude of the axial vibration of the axis of the rotary shaft 2 exceeds a certain level, There is a problem that the deformation of the gland packing 3 cannot be coped with, the plastic deformation remains and the gap C is generated, and the leakage increases. In addition, even if the gland packing 3 is repeatedly deformed to follow the shaft runout of the rotary shaft 2 even if it is retightened by the presser bolt 8, the gland packing 3 is worn or fatigue deteriorated, and elasticity or deformation adaptability is deteriorated. Then, there was a problem that the leak could be stopped only for a short period of time.

The present invention has been made in order to solve the above problems, and even if the rotating shaft has shaft runout or shaft vibration with a relatively large amplitude, the packing conforms to the displacement of the rotating shaft to form a gap. It is an object of the present invention to provide a shaft sealing device capable of preventing the leakage and preventing the fluid from leaking for a long period of time.

[0005]

In the shaft sealing device according to the present invention, instead of part or all of the gland packing, the inner peripheral surface is in contact with the rotating shaft, and the outer peripheral surface is movable with a gap between it and the packing box. A packing is inserted, and a smooth surface ring having a small surface friction resistance is inserted on both axial sides of the movable packing, and an elastic O-ring having a large elastic deformation performance in the gap between the outer peripheral surface of the movable packing and the packing box. Is inserted. Further, the slip ring is provided with an anti-rotation protrusion protruding in the axial direction, and a loose fitting hole into which the anti-rotation protrusion is loosely fitted with a predetermined margin is formed in the movable packing.

[0006]

The movable packing of the shaft sealing device according to the present invention is
Since the inner peripheral surface is in contact with the rotating shaft and the outer peripheral surface has a gap between it and the packing box, when shaft deflection occurs on the rotating shaft, the movable packing displaces together with the rotating shaft and creates a gap between it and the rotating shaft. Do not let With the displacement of the movable packing, the shape of the gap between the movable packing and the packing box changes, but the elastic O-ring, which has a large elastic deformation performance, elastically deforms according to the shape to close the gap and allow the passage of fluid. Prevent.
The smooth ring inserted on both sides in the axial direction of the movable packing is
Since the surface frictional resistance is small, it facilitates displacement of the movable packing due to shaft runout of the rotary shaft. In addition, the anti-rotation protrusion allows displacement of the movable packing only by the allowance of the loose fitting hole and blocks further rotation.Therefore, the movable packing rotates around with the rotation of the rotating shaft and wear or the like may occur at unexpected places. Prevent.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1A and 1B show a shaft sealing device according to a first embodiment of the present invention, wherein FIG. 1A is a longitudinal sectional view and FIG. 1B is a lateral sectional view. Figure 1
In the figure, 1 is a packing box, and 2 is a rotating shaft. The packing box 1 is provided at a location where the rotary shaft 2 penetrates a casing such as a pump so as to prevent fluid leakage. The packing box 1 has a space formed between it and the rotary shaft 2 for inserting packing. The gland packing 3, the smooth surface ring 6, the movable packing 4, the smooth surface ring 6, the movable packing 4, and the smooth surface ring 6 are formed. Further, the gland packing 3 is sequentially stacked and inserted, and the elastic O-ring 5 is inserted between the outer peripheral surface of each movable packing 4 and the inner peripheral surface of the packing box 1. Insert the packing retainer 7 so as to press it from above these stacked packings, insert the retainer bolt 8 through the flange hole of the packing retainer 7 and screw it into the screw hole of the packing box 1, tighten the nut, and remove the packing retainer 7. The gland packing 3 and the movable packing 4 are pushed in through the space to close the space between the packing box 1 and the rotary shaft 2.

As shown in FIG. 1, the inner diameter of the movable packing 4 is the same as the diameter of the rotating shaft 2, and the inner peripheral surface of the movable packing 4 is in contact with the outer peripheral surface of the rotating shaft 2 without a gap. The outer diameter of the movable packing 4 is smaller than the inner diameter of the packing box 1, and there is a gap between the outer peripheral surface of the movable packing 4 and the inner peripheral surface of the packing box 1. An elastic O-ring 5 is inserted in this gap. A conventional gland packing 3 may be used. The movable packing 4 also needs an appropriate elasticity, but since it is displaced following the deflection of the rotating shaft 2 as described later, it is necessary to use a polymer material such as fluororesin or polyamide, or to insert carbon or silicon. You may strengthen it. The elastic O-ring 5 is made of rubber having a large elastic deformation rate, and is a material that can withstand repeated large deformations as exaggerated in the left and right cross sections of FIG. 1 without fatigue.
It is formed so as to completely close the gap communicating in the vertical direction in the figure. The smooth ring 6 sandwiched between the packings is formed of a ring-shaped plate made of a material such as fluororesin, phenol resin, polyamide, and polyacetal, which has small surface friction resistance and self-lubricating property. The outer diameter of the smooth surface ring 6 is full of the inner diameter of the packing box 1, and the inner diameter is formed to be slightly larger than the diameter of the rotary shaft 2 in consideration of the expected amount of shake of the rotary shaft 2. The thickness of the smooth surface ring 6 may be such that the shape, function, etc. are retained. The axial thicknesses of the gland packing 3 and the movable packing 4 may be determined in consideration of handling and maintenance so that the leak sealing function can be exerted without hindrance.

Next, the operation of the embodiment shown in FIG. 1 will be described. Tighten the presser bolt 8, press the gland packing 3 and the movable packing 4 through the packing presser 7,
As described above, the gap between the packing box 1 and the rotary shaft 2 is closed to prevent the fluid from leaking. However, this shaft sealing device has a shaft runout so that the shaft center line of the rotary shaft 2 can be swung to some extent. The leak sealing function is maintained even if the conventional shaft sealing device leaks due to shaft vibration.

In this shaft sealing device, as shown in FIG. 1, the movable packing 4 is provided by inserting the smooth surface ring 6, and the elastic O-ring 5 is inserted in the gap behind the movable packing 4. When the rotary shaft 2 rotates and axial vibration occurs such that the axis of the rotary shaft 2 swings, the inner diameter of the movable packing 4 is formed to be the same as the diameter of the rotary shaft 2, and the inner peripheral surface of the movable packing 4 has the inner circumference. Since the movable packing 4 is closely contacted with the outer peripheral surface thereof and the upper and lower surfaces of the movable packing 4 are in contact with the smooth surface ring 6 having a small surface friction resistance, the movable packing 4 follows the displacement of the rotary shaft 2 and is displaced as shown in the figure. A gap is not formed between the inner peripheral surface of the movable packing 4 and the outer peripheral surface of the rotary shaft 2. At this time, the gap between the outer peripheral surface of the movable packing 4 and the inner peripheral surface of the packing box 1 is deformed so that the right side is wide and the left side is narrow at a certain moment, and the right side is deformed at the next moment. The elastic O-ring 5 inserted into this gap is formed into a shape necessary for closing the gap with a material having a large elastic deformation rate. Since it is elastically deformed so as to block the gap, fatigue does not occur even if the deformation is repeated. As described above, between the rotary shaft 2 and the movable packing 4, and between the movable packing 4 and the packing box 1,
The gap is blocked to prevent fluid leakage.

Next, a second embodiment shown in FIG. 2 will be described. Also in this shaft sealing device, similarly to the first embodiment described above, the movable packing 4 is provided by sandwiching the sliding surface ring 6, and the elastic O-ring 5 is inserted on the back surface of the movable packing 4. It is provided by forming a plurality of rotation preventing projections 9 projecting in the axial direction on the smooth surface ring 6 or by separately preparing and attaching the rotation preventing projections 9 to the smooth surface ring 6, and the rotation preventing projections 9 are loosely fitted. A loose fitting hole 9h is formed in the movable packing 4. The size of the loose fitting hole 9h is the movable packing 4
Is set to a size that allows displacement of the rotating shaft 2 due to the shake of the rotating shaft 2.

Next, the operation of the second embodiment shown in FIG. 2 will be described. The movable packing 4 is displaced following the runout of the rotary shaft 2 to form no gap between the rotary shaft 2 and the movable packing 4, and the elastic O-ring 5 is elastically deformed between the movable packing 4 and the packing box 1. Blocking the gap is the same as described above. At this time, the loose fitting hole 9h into which the detent 9 is loosely fitted
Allows the movable packing 4 to be displaced following the displacement of the rotating shaft 2, but even if the movable packing 4 tries to rotate as the rotating shaft 2 rotates, the rotation preventing projection 9 fitted in the loose fitting hole 9h The rotation is blocked by. As a result, the movable packing 4 is prevented from rolling around and the elastic O-ring 5 and the like are prevented from being worn.

In the embodiment shown in FIGS. 1 and 2, as the packing to be inserted into the packing box 1, the gland packing 3 is put on the upper and lower sides, and the two movable packings 4 are put between them. The packing 3 may be completely abolished, may be installed only in one of the upper and lower sides, or may be installed in the middle, and the number, arrangement, and combination of the gland packing 3 and the movable packing 4 may be appropriately changed.

[0014]

As described above, according to the present invention, the movable packing follows the runout of the rotary shaft even if the runout or shaft vibration occurs in the rotary shaft such that the axis of the rotary shaft is displaced. Therefore, a gap is not created between the rotary shaft and the movable packing, and the elastic O-ring elastically deforms between the movable packing and the packing box to block the gap. Therefore, even if shaft runout occurs on the rotary shaft,
Fluid leaks are well sealed for long periods.

[Brief description of drawings]

FIG. 1 shows a shaft sealing device according to a first embodiment of the present invention,
(A) is a vertical cross-sectional view and (B) is a horizontal cross-sectional surface.

FIG. 2 shows a shaft sealing device according to a second embodiment of the present invention,
(A) is a vertical cross-sectional view and (B) is a horizontal cross-sectional surface.

FIG. 3 shows a conventional shaft sealing device (A) is a longitudinal sectional view,
(B) is a cross-sectional view.

[Explanation of symbols]

1: packing box, 2: rotating shaft, 3: gland packing, 4: movable packing, 5: elastic O-ring, 6: smooth surface ring, 7: packing retainer, 8: retainer bolt, 9:
Non-rotating protrusion, 9h: loose fitting hole.

Claims (2)

[Claims] 1. A shaft sealing device for inserting and compressing a gland packing between a rotary shaft and a packing box to prevent leakage, the inner peripheral surface of which is replaced by the rotary shaft instead of part or all of the gland packing. A movable packing having a gap between the outer peripheral surface and the packing box is inserted, and a smooth surface ring having a small surface friction resistance is inserted on both axial surfaces of the movable packing, and the movable packing and the packing box are arranged between the movable packing and the packing box. A shaft sealing device characterized in that an elastic O-ring having a large elastic deformation performance is inserted in the gap. 2. A shaft sealing device for inserting and compressing a gland packing between a rotating shaft and a packing box to prevent leakage, the inner peripheral surface of which is replaced by the rotating shaft instead of part or all of the gland packing. A movable packing having a gap between the outer peripheral surface and the packing box is inserted, and a smooth surface ring having a small surface friction resistance is inserted on both axial surfaces of the movable packing, and the movable packing and the packing box are arranged between the movable packing and the packing box. An elastic O-ring having a large elastic deformation performance is inserted in the gap, and a detent protrusion projecting in the axial direction is provided on the smooth surface ring. A loose fitting hole in which the detent protrusion is loosely fitted with a predetermined margin is provided in the movable packing. A shaft seal device characterized by being formed.