JPH0645173U - Gland packing and shaft sealing device - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a local sealing function to the part from the side surface to the outer peripheral surface when it is fitted onto the rotating shaft in the packing box of the shaft sealing device. [Structure] Side 30 of annular gland packing body 30
An annular groove 32 is formed around the axis of the annular groove 32 in at least one of the portions from a, 30b to the outer peripheral surface 30c, and an annular seal member 31 that is harder than the gland packing body 30 is fitted into the annular groove 32. To do.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention is a packing applied to a fluid machinery such as a pump or an agitator, or a shaft sealing portion of a propulsion shaft of a ship, and a gland packing and a gland packing suitable for a shaft sealing portion of a device which easily causes shaft runout at high speed rotation. The present invention relates to a shaft sealing device using the gland packing.

[0002]

[Prior art]

 Conventionally, as a shaft seal device of this type used in, for example, a pump, a structure shown in FIG. 13 is known. In FIG. 13, 1 is a packing box, which is formed at one end of the pump casing. Reference numeral 2 denotes a gland packing attachment member, which is composed of, for example, a neck bush 2A inserted in the inner part of the packing box 1 and a packing retainer 2B having its tip fitted in the opening of the packing box 1. Reference numeral 130 denotes an annular gland packing, which is made of braided fibers and impregnated with polytetrafluoroethylene (hereinafter abbreviated as PTFE). In the packing box 1, an axial gland packing member 2 is used for axial direction. It is attached to the rotary shaft 4 and is fitted onto the rotary shaft 4. 5 is a tightening means for tightening the gland packing 130 so that it can be retightened. For example, a stud bolt 7 that is planted at the opening end surface of the packing box 1 and penetrates the bolt insertion hole 6 of the packing retainer 2B, The stud bolt 7 is composed of a nut 9 screwed to an outer end side screw portion 8 and a spring 10 externally fitted to the stud bolt 7 between the packing retainer 2B and the nut 9.

In the shaft sealing device having the above structure, when the nut 9 screwed to the stud bolt 7 is screwed to tighten the packing retainer 2B to the inner side of the packing box 1 as shown by the arrow x, the gland is removed. One end surface of the packing 130 in the axial direction is held in contact with the holding surface 2a of the neck bush 2A, and the other end surface is held in contact with the holding surface 2b of the packing retainer 2B. As a result, the inner peripheral surface of the gland packing 130 is brought into close contact with the outer peripheral surface of the rotating shaft 4, and the seal portion 11 is formed between the inner peripheral surface of the gland packing 130 and the outer peripheral surface of the rotating shaft 4. Become.

[0004]

[Problems to be solved by the device]

 Since the gland packing 130 in the conventional shaft sealing device having the above-mentioned structure is entirely constructed as a soft packing by braiding fibers, when the gland packing 130 is tightened in the packing box 1 by the tightening means 5, As shown in FIG. 14, the inner peripheral surface of the packing box 1 and the outer peripheral surface of the rotating shaft 4 are deformed so that a contact portion C and a non-contact portion g exist. The non-contact portion g on the inner peripheral surface side of the gland packing 130 contributes to the lubrication and cooling of the infiltrated fluid. However, when the fluid enters the side surface of the gland packing 130 or the non-contact portion g on the outer peripheral surface side, The gland packing 130 floats in the fluid, and the holding force for the rotating shaft 4 is reduced. Therefore, when shaft runout occurs, there is a problem in that the adhesion to the outer peripheral surface of the rotary shaft 4 decreases, the leakage behavior becomes unstable, and the sealing performance significantly deteriorates.

The present invention has been made to solve the above-mentioned problems, and improves the sealing performance by forming a local seal surface at a portion from the side surface to the outer peripheral surface by a simple improvement. Another object of the present invention is to provide a gland packing that can be used, and further to provide a shaft sealing device that can secure the holding force of the ground packing with respect to the rotating shaft and further enhance the sealing function.

[0006]

[Means for Solving the Problems]

 In order to achieve the above object, the gland packing according to the present invention has an annular groove formed around the axial center of the gland packing body in at least one position from the side surface to the outer peripheral surface of the gland packing body. An annular seal member that is harder than the main body of the gland packing is fitted in the annular groove.

In the gland packing, it is preferable that the annular groove is formed at a plurality of positions from a side surface to an outer peripheral surface of the grant packing body, and an annular seal member is fitted in each of the annular grooves.

Further, in the shaft sealing device according to the present invention, a hard annular seal member is attached to a portion of the above-mentioned rotating shaft in the packing box through which the rotating shaft penetrates, from a side surface to an outer peripheral surface of the gland packing body. The ring-shaped gland packing formed as described above is externally fitted, and a tightening means is provided for tightening the gland packing so that it can be further tightened in the axial direction via the gland packing fitting member fitted in the packing box. .

The gland packing holding member in the shaft sealing device is composed of a neck bush and a packing retainer for holding the gland packing from both sides in the axial direction, and the gland packing holding member holds the gland packing on the holding surface. It is preferable that at least one displacement portion that displaces the gland packing in the axial direction is formed.

[0010]

[Action]

 According to the gland packing of the present invention, since the hard annular seal member is mounted on the part from the side surface to the outer peripheral surface of the gland packing body, the part from the side surface to the outer peripheral surface has a local sealing function. be able to.

Further, according to the shaft sealing device of the present invention, leakage of fluid from the outer peripheral side of the gland packing is prevented by the local sealing function at the portion from the side surface to the outer peripheral surface of the gland packing. In addition, the holding force for the rotating shaft is effectively maintained, and as a result, the resilience to the opening of the seal surface at the time of shaft run-out is enhanced.

Further, when the displacement portion is formed on the holding surface of the gland packing holding member, the leakage fluid is sent to the inner peripheral surface of the gland packing with the rotation of the rotating shaft, and the lubricating function and the cooling function are effective. To be demonstrated.

[0013]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a vertical cross-sectional view showing a shaft sealing device using a gland packing according to an embodiment of the present invention. In FIG. 1, the same parts as those of the conventional example shown in FIG. Is omitted.

In FIG. 1, reference numeral 3 denotes an annular gland packing that is fitted onto the rotary shaft 4 in the packing box 1. The gland packing main body 30 and an O-shaped seal member that is harder than the gland packing main body 30 are used as an example. It consists of a ring 31. The gland packing body 30 is formed by braiding fibers and impregnating with PTFE to form an annular ring having a rectangular cross section. As shown in FIG. 2, the gland packing body 30 extends from the side surfaces 30a, 30b to the outer peripheral surface 30c. An annular groove 32 is formed around a portion of the outer peripheral surface 30c in the axial direction, and the O-ring 31 is fitted in the annular groove 32. The O-ring 31 is made of, for example, nitrile rubber (NBR), fluorine rubber (FPM), silicon rubber, or fluorine resin (PTFE).

At least one displacing portion 20a, 20b for displacing the gland packing 3 in the axial direction is provided on each of the clasping surfaces 2a, 2b of the neck bush 2A and the packing retainer 2B constituting the gland packing clasping member 2. Are formed respectively.

In the shaft sealing device having the above-mentioned configuration, when the nut 9 is screwed to tighten the packing retainer 2B in the axial direction toward the inner side of the packing box 1, one end face in the axial direction of the gland packing 3 is removed. Since the other end surface is pressed against the packing surface 2a of the neck bush 2A and the other end surface is pressed against the packing retainer 2B, the inner peripheral surface of the gland packing 3 is in close contact with the outer peripheral surface of the rotating shaft 4, and the inner surface of the gland packing 3 A seal portion 11 is formed between the peripheral surface and the outer peripheral surface of the rotary shaft 4.

In this case, since the gland packing 3 is partially displaced in the axial direction by the respective displacement portions 20a, 20b of the clad surfaces 2a, 2b, the inner peripheral surface of the gland packing clad member 2 and the rotary shaft 4 are A part of the annular gap formed by the outer peripheral surface overlaps the inner peripheral surface of the ground packing 3 in the circumferential direction. Therefore, as the rotary shaft 4 rotates, the fluid is forcibly sent to the inner peripheral surface of the overlapping gland packing 3 and reaches the seal portion 11, so that the lubrication function and the cooling function are improved.

Here, the gland packing body 30 is deformed as shown in FIG. 3 when it is attached to the gland packing attachment member 2, and the side surfaces 30a and 30b and the outer peripheral surface 30c are not joined together with the contact portion C. Although the contact portion g is formed, the line contact portion C1 formed by the O-ring 31 mounted on the outer peripheral surface 30c provides a local seal surface, and leak fluid that does not contribute to lubrication / cooling is provided on the outer peripheral side. It is effectively prevented to try to penetrate into. Therefore, the state in which the gland packing 3 floats on the fluid is avoided, and the holding force for the rotating shaft 4 is effectively maintained. Therefore, the recovery force for the opening of the seal surface is strengthened due to shaft runout of the rotary shaft 4. In addition, the O-ring 31 applies a local pressure to the sliding surface of the gland packing 3 to improve the sealing performance.

Regarding the stress generated when the fluid acts on the gland packing 3 at this time, as shown in FIG. 4, the contact pressure on the outer peripheral surface of the rotating shaft 4 is indicated by the dotted arrow with respect to the fluid pressure indicated by the solid arrow. It becomes the pattern shown.

As shown in FIG. 5, the O-ring 31 may be attached to the outer peripheral surface 30c of the gland packing body 30 at a position offset to one side in the axial direction, or as shown in FIG. In addition, a plurality of O-rings 31, 31 may be attached to the outer peripheral surface 30c at intervals in the axial direction. In these cases, the contact pressure on the outer peripheral surface of the rotary shaft 4 becomes a pattern shown by a dotted arrow. .

Further, the O-ring 31 is not limited to the outer peripheral surface 30c of the gland packing body 30, but as shown in FIG. 7, one of the side surfaces 30a and 30b of the gland packing body 30, or FIG. As shown in FIG. 9, it may be provided on both side surfaces 30a and 30b, and as shown in FIG. 9, it may be provided on both corner portions of both side surfaces 30a and 30b of the gland packing body 30 and the outer peripheral surface 30c. It is possible. The relationship between the fluid pressure and the contact pressure at each mounting position of the O-ring 31 shown in FIGS. 5 to 9 is shown by an arrow in each drawing. That is, various contact pressure patterns can be made to appear depending on the mounting position of the O-ring 31.

FIG. 10 shows a result obtained by incorporating the above-mentioned gland packing 3 into a test device in which the shaft runout of the rotary shaft 4 is set to 0.2 mm, and calculating the seal gap when the fluid pressure is changed from the leakage amount. It is shown in comparison with the case where the conventional gland packing is used. Here, water is used as the fluid, the size of the gland packing 3 (130) is φ100 × φ129, the rotation speed of the rotary shaft 4 is 1910 rpm., And the fluid pressure is 0.1 to 4.0 kgf / cm ^2. Fig. 10 shows the test results when the values were changed between the two.

As is clear from the results of FIG. 10, in the conventional case, as shown by the characteristic of the dotted line, the seal gap greatly changes due to the fluctuation of the fluid pressure, and the leakage behavior becomes unstable. With the gland packing 3, it was confirmed that the change in the seal gap due to the change in fluid pressure was small, as shown by the solid line characteristics.

In the above embodiment, the gland packing 3 has been described as being clamped from both sides in the axial direction by the neck bush 2A and the packing retainer 2B of the gland packing clamping member 2, but as shown in FIG. Even if the gland packing 3 is sandwiched from one side in the axial direction to the back side of the packing box 1 by using only the packing presser 2B, the same effect can be obtained.

FIG. 12 shows another embodiment of the shaft sealing device of the present invention, in which the pressurized fluid Q is supplied to the outer peripheral surface 30c of the gland packing 3 through the pressurized water supply hole 12 formed in the packing box 1. In this case, the holding force of the ground packing 3 with respect to the rotating shaft 4 can be further increased by the pressurized fluid Q. In the figure, 13 is an O-ring provided on the outer peripheral side of the packing retainer 2B for sealing the inner peripheral surface of the packing box 1.

The number of gland packings 3 fitted onto the rotary shaft 4 in the packing box 1 is not limited to one, and a plurality of gland packings 3 may be fitted on the rotary shaft 4 in parallel. .

Further, the annular seal member 31 mounted on the gland packing body 30 is not limited to the O ring, but may be another seal material harder than the gland packing body 30, such as an X-shaped cross section. It can be appropriately selected from an X ring, a square ring, a V ring and the like.

[0028]

[Effect of device]

 As described above, according to claims 1 and 2 of the present invention, by mounting the annular seal member, which is harder than the gland packing body, on the part from the side surface to the outer peripheral surface of the gland packing body, It is possible to form a local sealing surface at a position from the side surface to the outer peripheral surface. Therefore, the high sealing performance is achieved by the leakage fluid that does not contribute to the lubrication / cooling trying to infiltrate to the outer peripheral side and locally pressurize the hard annular seal member on the outer peripheral surface of the rotating shaft. be able to.

Further, according to claim 3 of the present invention, a gland packing having an annular seal member is externally fitted to the rotary shaft in the packing box, and the gland packing is clamped to further tighten the ground packing from the axial direction. Since it is tightened as much as possible, leakage fluid is prevented from entering the gland packing from the side surface to the outer peripheral surface, the holding force of the ground packing on the rotating shaft is strengthened, and high sealing performance is achieved even when the shaft is running out. Can be reliably demonstrated.

Further, according to claim 4 of the present invention, since the gland packing is axially changed by the displacement portions formed on the respective clamping surfaces of the neck bush and the packing retainer constituting the gland packing clamping member, With the rotation of the rotating shaft, the fluid can be efficiently sent to the inner peripheral surface of the gland packing for lubrication and cooling.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a shaft sealing device using a gland packing according to an embodiment of the present invention.

FIG. 2 is an enlarged vertical sectional view of a half of a gland packing used in the shaft sealing device in the example.

FIG. 3 is an enlarged cross-sectional view showing a contact state of the gland packing in the embodiment.

FIG. 4 is a diagram showing a fluid pressure acting on a gland packing and a contact pressure pattern in the example.

FIG. 5 is a diagram showing a fluid pressure and a contact pressure pattern which act when the O-ring mounting position is shifted on the outer peripheral surface of the gland packing body.

FIG. 6 is a diagram showing a fluid pressure and a contact pressure pattern that act when two O-rings are attached on the outer peripheral surface of the gland packing body.

FIG. 7 is a diagram showing a fluid pressure and a contact pressure pattern acting in that case with an O-ring attached to the side surface of the gland packing body.

FIG. 8 is a diagram showing a fluid pressure and a contact pressure pattern which act when the O-rings are attached to both side surfaces of the gland packing body.

FIG. 9 is a diagram showing a fluid pressure and a contact pressure pattern that act when the O-rings are attached to both corners of the side surface and the outer peripheral surface of the gland packing body.

FIG. 10 is a characteristic diagram showing the test results of the change in the seal gap when the fluid pressure is changed in the example shown in FIG. 1, in comparison with the conventional one.

FIG. 11 is a vertical sectional view of a shaft sealing device according to another embodiment of the present invention.

FIG. 12 is a vertical cross-sectional view of a shaft sealing device according to still another embodiment of the present invention.

FIG. 13 is a vertical sectional view showing a shaft sealing device using a conventional gland packing.

FIG. 14 is an enlarged cross-sectional view showing a contact state of a conventional gland packing.

[Explanation of symbols]

 1 packing box 2 gland packing holding member 2A neck bush 2a, 2b holding surface 2B packing retainer 3 gland packing 4 rotary shaft 5 tightening means 20a, 20b displacement part 30 gland packing body 30a, 30b side of gland packing body 30c gland Outer peripheral surface of packing body 31 Seal member 32 Annular groove

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor, Kaichi Obata 1 at 541, 541, Shimuchi Shinji, Uchiba, Sanda City, Hyogo Prefecture Inside Pillar Industry Co., Ltd. Mita Factory

Claims (4)

[Scope of utility model registration request] 1. An annular groove is formed around the axis of the gland packing body in at least one part from the side surface to the outer peripheral surface of the annular gland packing body, and the annular groove is made of a harder material than the gland packing body. A gland packing having an annular seal member fitted therein. 2. The annular groove is formed at a plurality of locations from a side surface to an outer peripheral surface of the grant packing body,
The gland packing according to claim 1, wherein an annular seal member is fitted in each of these annular grooves. 3. A ring-shaped gland packing having a hard ring-shaped seal member mounted on a part of the gland packing body from a side surface to an outer peripheral surface of the gland packing body is externally fitted to the part of the gland packing body where the gland packing body is penetrated. The shaft sealing device is provided with a tightening means for tightening the gland packing so as to be able to be further tightened in the axial direction via the gland packing clamping member fitted in the packing box. 4. The gland packing holding member is composed of a neck bush and a packing retainer for holding the gland packing from both sides in the axial direction, and the gland packing is attached to the holding surface of the gland packing holding member. The shaft sealing device according to claim 3, wherein at least one displacement portion for partially displacing in the direction is formed.