JPH04362375A - Shaft sealing device - Google Patents

Abstract

PURPOSE:To maintain the sealing performance of seal members fitted to the periphery of a rotary shaft of a fluid machine so as to heighten lubricating performance and to enable the optional adjustment of a leakage amount related to this lubricating performance according to a condition at the working time while attaining easy machinability and cost reduction. CONSTITUTION:Wave springs 11, 14, 21 are provided on both sides of at least one side in the axial direction of elastically deformable seal members 3, 15, 17, 18, 19 fitted to the periphery of a rotary shaft 5 and clamped by seal pressing members 4. The seal members 3, 15, 17, 18 are locally displaced in the axial direction by these wave springs 11, 14, 21 to form waveform displaced parts.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shaft seal device used for shaft sealing of fluid machinery.

0002

2. Description of the Related Art FIG. 15 shows a gland packing box to which this kind of conventional sealing device is applied. In the figure, 1 is a packing box formed, for example, at one end of a pump casing, and 2 is a neck. 3 (3A, 3B) is a gland packing; 4 is a packing holder as a seal holding member; 5 is a rotating shaft; and packing box 1
With the packing retainer 4 whose tip is fitted into the opening of
It is clamped in the axial direction by a predetermined tightening pressure to ensure sealing performance against the rotating shaft 5.

By the way, the structure of the gland packing box is such that the outer peripheral surface of the rotating shaft 5 and the gland packings 3A and 3B are connected to each other.
A small amount of fluid is allowed to leak from the seal portion 6 with the inner circumferential surface of the rotating shaft 5, and this leaked liquid has a lubricating function to prevent abnormal wear of the rotating shaft 5 and seizure of the seal portion 6.

However, in the structure of the conventional packing box described above, the gland packing clamping surfaces 2a and 4a that contact the gland packings 3A and 3B of the neck bush 2 and the packing presser 4, respectively, are perpendicular to the axis of the rotating shaft 5. Since the gland packings 3A and 3B are sandwiched between the packing clamping surfaces 2a and 4a, the axial end surfaces of the gland packings 3A and 3B are naturally aligned with the axis of the rotating shaft 5. perpendicularly and uniformly intersects. Therefore, the locus around the rotating shaft 5 formed by the axial end faces of the gland packings 3A, 3B and the outer peripheral surface of the rotating shaft 5 is always maintained within a plane perpendicular to the axis of the rotating shaft 5, and 5, its locus does not overlap the inner circumferential surface of the gland packing 3A in the circumferential direction.

Therefore, leakage fluid that functions as a lubricant is leaked from only the axially inner end of the small annular gap 7 formed between the inner circumferential surface of the neck bushing 2 and the outer circumferential surface of the rotating shaft 5 to the seal portion 6. will be sent to. However, when the packing holder 4 is tightened with a predetermined tightening pressure, the neck bush 2
By tightening in the direction, the inner circumferential surfaces of each of the gland packings 3A and 3B are brought into pressure contact with the outer circumferential surface of the rotating shaft 5, thereby ensuring suitable sealing performance.
The inner circumferential surfaces of the gland packings 3A and 3B forming the seal portion 6 and the outer circumferential surface of the rotating shaft 5 are in close contact with each other, and leakage fluid is sent to such a seal portion 6 only by the fluid pressure within the casing. It is actually difficult to
The leakage flow rate is small and limited, making it impossible to effectively demonstrate the lubrication function.

For this reason, as shown in FIG. 16, conventionally, gland packings 3A and 3B are attached to the clamping surfaces 2a and 4a of the neck bushing 2 and the packing retainer 4, respectively, in the axial direction, which constitute the gland packing clamping part. As a means for biasing in the direction, a plurality of (four in the figure) projecting piece-shaped displacement parts 2A...
, 4A... (FIG. 17) have been proposed in which they are formed at predetermined intervals in the circumferential direction. This is the gland packing 3A formed by the height difference in the axial direction between the protruding displacement parts 2A..., 4A... of the neck bush 2 and the clamping surfaces 2a, 4a.
, 3B and the outer circumferential surface of the rotating shaft 5 overlap with the inner circumferential surface of the gland packing 3A, which is not displaced inward in the axial direction as the rotating shaft 5 rotates. In addition, the small gap 8 on the side of the packing holder 4 also overlaps in the circumferential direction with the inner circumferential surface of the gland packing 3B which has not been displaced inward in the axial direction. Therefore, the leaked fluid is forcibly fed into the inner peripheral surface of the gland packing 3A as the rotating shaft 5 rotates, and the fluid leaked through the seal portion 6 to the lower part of the small annular gap 8 is The gland packing 3B is forcibly removed as the rotating shaft 5 rotates.
The lubricating function can be improved.

Further, as shown in FIG. 18, curved displacement portions 2B are provided on the clamping surfaces 2a and 9a of the inner ring 9 of the neck bush 2 and the packing retainer 4, respectively, for displacing the gland packings 3A to 3C in the axial direction. , 9B, and a coil spring 10 is interposed between the inner end of the packing box 1 and the neck bushing 2, and the spring force is transmitted through the neck bushing 2 to the gland packing 3A.
〜3C in the axial direction and the gland packing 3A〜3
It has also been proposed that the stress relaxation occurring in C over time is compensated for by the spring force of the coil spring 10.

[0008]

[Problems to be Solved by the Invention] In the conventional shaft seal device having the above-mentioned configuration, the gland packings 3A to 3C are aligned with the axis due to the shape of the clamping surfaces of the gland packing clamping members such as the neck bush 2 and the packing retainer 4. Since the leakage amount is set in advance, curved displacement parts 2B, 9B, etc., corresponding to the amount of packing displacement are processed on the clamping surface of the gland packing clamping part. must be administered. Therefore, if fluid conditions or the like are changed during mounting, this cannot be accommodated and a new one must be manufactured. Furthermore, the curved displacement portions 2B, 9B, etc. must be processed by cutting, which is time consuming and increases costs. Moreover, if it is used in combination with a coil spring 10 or the like, it will result in an increase in size.

The present invention has been made in view of the above-mentioned circumstances, and it is possible to effectively feed fluid into the seal portion without deteriorating the sealing performance and to maintain a good lubrication function based on the amount of leakage. It is an object of the present invention to provide a shaft sealing device that can prevent the occurrence of abnormal wear of the shaft, can arbitrarily adjust the amount of leakage during use, is inexpensive, easy to manufacture, and can be downsized.

0010

[Means for Solving the Problems] In order to achieve the above object, a shaft seal device according to the present invention includes a seal that is fitted onto the rotating shaft that passes through a casing and is screwed onto one end of the casing in the axial direction. A wave spring for locally displacing the seal member in the axial direction is disposed on at least one side surface in the axial direction of an elastically deformable ring-shaped seal member that is tightened by a holding member.

Further, it is preferable that the wave spring is interposed between the seal member and the seal pressing member.

0012

[Operation] According to the above configuration, the sealing member is pushed in the axial direction by the wave spring, so that a continuous wave is formed on the axial end face of the sealing member due to the height difference in the axial direction between the peaks and troughs of the wave spring. A wave-shaped displacement portion is formed, and this wave-shaped displacement portion overlaps the inner circumferential surface of the seal member in the circumferential direction as the rotating shaft rotates. Therefore, as the rotating shaft rotates, the fluid is forcibly fed into the inner peripheral surface of the overlapping seal member.
Not only can effective lubricity be obtained, but also a balance with sealing performance can be maintained by adjusting the amount of pressing, and furthermore, this can be adjusted arbitrarily according to the conditions of use.

Furthermore, when the wave spring is interposed between the sealing member and the holding member, when the fluid pressure increases, the wave spring becomes flattened by the fluid pressure, so that the sealing performance is improved. can be achieved.

[0014]

Embodiments Hereinafter, embodiments of the present invention will be explained based on the drawings. FIG. 1 is a cross-sectional view showing an example in which the shaft seal device according to the present invention is applied to a packing box, and in the same figure,
The same parts as in the conventional example shown in FIGS. 15 to 18 are denoted by the same reference numerals, and their explanation will be omitted.

In FIG. 1, a ring-shaped single-wound wave spring 11 (11A, 11B) are in contact with each other. The gland packing 3 is fabricated from a braided carbonized fiber impregnated with PTFE. Also,
The wave spring 11 is made of a plate spring or the like as shown in FIG.
It is punched out in a ring shape, and has a crest 11a in the circumferential direction.
It is formed into a relatively large waveform with valleys 11b. While the axial position of one wave spring 11B is restricted by the inner wall step 1a of the packing box 1, the other wave spring 11A is connected to the packing holder 4 screwed onto the packing box 1 and the gland packing 3. The gland packing 3 is interposed therebetween and tightened in the axial direction by the screw movement of the packing holder 4, thereby bringing the inner circumferential surface of the gland packing 3 into close contact with the outer circumferential surface of the rotating shaft 5, thereby tightening the inner circumferential surface of the gland packing 3. A seal portion 6 is formed by the surface and the outer circumferential surface of the rotating shaft 5.

In such a configuration, the axial end face of the gland packing 3 is connected to the wave springs 11A, 1
A locally displaced portion in the axial direction is formed intermittently in the circumferential direction due to the height difference between the peak portion 11a and the valley portion 11b of 1B, that is, a wave-shaped displacement portion is formed, and this wave-shaped displacement portion rotates. As the shaft 5 rotates, it sequentially overlaps the inner peripheral surface of the gland packing 3. Therefore, as the rotating shaft 5 rotates, the fluid is forcibly fed into the seal portion 6 as leakage fluid and is evenly distributed, thereby improving lubricity.

Since the gland packing 3 is displaced in the axial direction by the wave spring 11, the amount of displacement in the axial direction can be adjusted arbitrarily by changing the installation length of the seal unit consisting of the wave spring 11, the gland packing 3, etc. It can be adjusted to In other words, even after the seal unit is mounted, the tightening pressure can be set to a desired amount by changing the tightening pressure by the screw operation of the packing holder 4, thereby increasing versatility. In addition, since the wave spring 11 is interposed between the gland packing 3 and the packing retainer 4, when the fluid pressure becomes high, the peaks 11a and troughs 11 of the wave spring 11
Since the height difference with b becomes smaller and becomes flattened, the sealing performance is automatically improved.

Furthermore, since the wave spring 11 can be formed by press forming a spring steel plate or a stainless steel plate, it is easy to process and can be manufactured at low cost. The length can be significantly shortened.

By the way, if there is a possibility that the gland packing 3 may protrude from the gap between the inner circumferential surface of the wave spring 11 and the outer circumferential surface of the rotary shaft 5 due to fluid pressure, as shown in FIG. Adapter ring 1 consisting of
3A and 13B may be inserted, thereby improving the pressure resistance.

FIG. 4 shows another embodiment of the present invention, in which the gland packing 3 is a single-wound wave spring 11A.
and a multi-wound wave spring (FIG. 5), and an adapter ring 13 is also used. In this example, the amount of displacement of the gland packing 3 in the axial direction can be increased, and it becomes possible to cope with weight loss due to wear of the gland packing 3, etc.

Incidentally, in each of the above embodiments, the gland packing 11 was used as the sealing member, but as shown in FIG.
1A may be pressed. This O-ring 15
In this case, the amount of displacement in the axial direction can be increased, the amount of leakage can be increased, and the lubricity can be improved. Of course, as shown in FIG. 7, the O-ring 15 may be sandwiched between a pair of wave springs 11A and 11B.

[0022] Also, in place of the above O-ring 15,
As shown in FIG.
If the FE composite O-ring 17 is used, sliding resistance can be reduced.

FIG. 9 shows still another embodiment of the present invention,
A ring 18 made of porous PTFE is used as a sealing member. This porous PTFE ring 18 is
It is manufactured using a stretching method to have a density of 1.0, and the sliding resistance against the rotating shaft 5 is reduced due to PTFE, and the lubricating oil can be retained due to its porous nature.

FIG. 10 shows still another embodiment of the present invention, in which a lip seal 19 made of PTFE having a tongue portion 19a on the inner circumferential side is used as a sealing material, and a garter spring 20 wrapped around the outer circumferential side is used. The contraction spring force is applied to the tongue portion 19a, which has the advantage of improving followability against shaft runout.

Note that the above-mentioned wave spring is not limited to the one described above, and if a multi-wound wave spring 21 as shown in FIG. 11 is used, for example, it can cope with high loads.

[0026] Also, the wave spring 11 (14)
) and (21) may be prevented from rotating as necessary. For example, if the other party is a rotation stopper pin (not shown), an engagement hole 22 for pin engagement as shown in FIG. 12 may be formed, and if the other party is a rotation stopper groove (not shown), A bent piece 23 for groove engagement as shown in FIG. 13 may be formed. Alternatively, a notch 24 for a rotation preventing protrusion as shown in FIG. 14 may be used.

[0027]

As described above, according to the present invention, the wave spring partially displaces the seal member in the axial direction when the seal member, which is fitted onto the rotating shaft and is elastically deformable, is clamped in the axial direction. Since the structure is configured to allow the wave spring to move, a wave-shaped displacement portion is formed on the end face of the seal member in the axial direction due to the height difference in the axial direction between the peaks and troughs of the wave spring, and as the rotating shaft rotates, the wave-shaped displacement portion is formed. The locus of the wave-shaped displacement portion overlaps the inner circumferential surface of the seal member in the circumferential direction, and fluid is forcibly fed into the seal portion from here to create a trowel. Therefore, while maintaining sealing performance,
In addition to improving lubricity, it is possible to set the balance between sealing performance and lubricity appropriately depending on the conditions of use, and it is also easy to process, inexpensive, and easy to downsize. .

Further, according to claim 2, since the wave spring is disposed between the seal member and the seal pressing member, when the pressure of the fluid becomes high, the wave spring flattens in the axial direction and the fluid pressure is reduced. The sealing performance can be improved as the value increases.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a first embodiment in which a shaft seal device according to the present invention is applied to a packing box.

FIG. 2 is a perspective view showing the wave spring used in the one in FIG. 1;

FIG. 3 is a sectional view showing a second embodiment of the present invention.

FIG. 4 is a sectional view showing a third embodiment of the present invention.

FIG. 5 is a perspective view showing the multi-wound wave spring used in the one in FIG. 4;

FIG. 6 is a sectional view showing a fourth embodiment of the present invention.

FIG. 7 is a sectional view showing a fifth embodiment of the present invention.

FIG. 8 is a sectional view showing a sixth embodiment of the present invention.

FIG. 9 is a sectional view showing a seventh embodiment of the present invention.

FIG. 10 is a sectional view showing an eighth embodiment of the present invention.

FIG. 11 is a perspective view showing a lap-wound wave spring.

FIG. 12 is a perspective view showing a wave spring having an engagement hole for a rotation stopper pin.

FIG. 13 is a perspective view showing a wave spring with a bent piece for a rotation stopper groove.

FIG. 14 is a perspective view showing a wave spring having a cutout for a rotation preventing protrusion.

FIG. 15 is a sectional view showing a general shaft seal device.

FIG. 16 is a sectional view showing an example of a conventional shaft seal device.

17 is a perspective view showing the main parts of the gland packing clamping member used in the one shown in FIG. 16. FIG.

FIG. 18 is a sectional view showing another example of a conventional shaft seal device.

[Explanation of symbols]

1 Casing 3, 15, 17, 18, 19 Seal member 4 Seal pressing member 5 Rotating shaft

Claims (2)

[Claims] 1. At least one side surface in the axial direction of an elastically deformable ring-shaped seal member that is fitted onto a rotating shaft passing through a casing and tightened by a seal presser member that is screwed onto one end of the casing in the axial direction. A shaft sealing device characterized in that a wave spring for locally displacing the sealing member in the axial direction is disposed on the side thereof. 2. The shaft seal device according to claim 1, wherein the wave spring is interposed between the seal member and the seal presser member.