JP2821989B2 - 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 used as a shaft sealing portion in various fluid devices such as a pump for rainwater, sewage, seawater, river water or irrigation water.

[0002]

2. Description of the Related Art For example, in a horizontal-axis mixed flow pump used for draining river water, a sleeve 103 is provided on a rotating shaft through hole 102 formed in a casing 101 and on an outer peripheral surface as shown in FIG. Penetrating the fitted rotating shaft 104,
The gland packing 106 is inserted into an annular packing fitting groove 105 formed on the inner peripheral surface of the casing 101 corresponding to the sleeve 103, and the gland packing 10 is inserted.
6 is fixed to the casing 101 by a pressing wheel 10
7 is pressed toward the pump liquid S side (rear side) at the axial inner end surface 107a, and the packing fitting groove 10 is inserted into the casing 101.
A gland packing type shaft sealing device having a flushing hole 108 reaching up to 5 is used.

However, the shaft packing device of the above-mentioned gland packing type requires a separate water supply device to prevent seizure of the gland packing 106, so that the structure of the device becomes complicated, and the shaft sealing device before starting the pump is also required. There is a disadvantage that it takes a long time to reach a steady operation due to a large amount of air suction in evacuation.

In place of such a gland packing type shaft sealing device, a shaft sealing device using an elastic seal ring made of NBR or the like has been conventionally developed and used.
As one example, a shaft sealing device having a configuration as shown in FIG. 6 is known. The shaft sealing device is provided on the side wall 1 of the casing 101.
01a is fixed to the casing 101, and the side wall 101a and the plate 109 are fixed to the casing 101.
A substantially V-pulley-shaped elastic seal ring 110 having flanges 110a and 110b having a vertical cross-section at both ends in the axial direction is fixed to the outer peripheral surface of the rotating shaft 104 between the elastic seal ring 110 and one of the elastic seal rings 110. The outer peripheral surface 110c of the flange 110a is slid on the inner surface 101b of the side wall 101a, and the outer peripheral surface 110d of the other flange 110b is slid on one side 109a of the plate 109, and A space P surrounded by the casing 101, the plate 109 and the elastic seal ring 110 is filled with grease G as a lubricant,
According to this shaft sealing device, the outer peripheral surfaces 110 c and 110 d of the flange portions 110 a and 110 b at both ends in the axial direction of the elastic seal ring 110 and the side wall 1 of the casing 101.
The space between the inner peripheral surface 101b of the first plate 01a and the one side surface 109a of the plate 109 is set as a boundary surface lubricated state by the grease G and used as a seal surface.

As another example of a shaft sealing device using an elastic seal ring, a structure as shown in FIG. 7 is conventionally known. This shaft sealing device is of a submersion type used in a submerged state, and has basically the same configuration as that shown in FIG. 6, but requires disassembly and assembly of components on the rotating shaft 104 in water. Therefore, the sleeve 111 is inserted and fixed to the outer peripheral surface of the rotating shaft 104 via the fixing member 112, and the elastic seal ring 1 is attached to the outer peripheral surface of the sleeve 111.
10 is adopted.

[0006]

Among the conventional shaft sealing devices having the above-mentioned construction, the one shown in FIG. 6 has a space P on the radial outside of the elastic seal ring 110 filled with grease G. A centrifugal force acts on the grease G with the rotation of the rotating shaft 104, and as the rotation speed increases, the grease G moves radially outward, causing the oil (grease) to run out on the sealing surface, thereby deteriorating the sealing performance. As a result, seizure of the sliding contact surface is likely to occur. In addition, the elastic seal ring 1
10 is only air-cooled and the cooling effect is insufficient, so that the permissible shaft diameter peripheral speed is also limited to 1 m / sec. Also,
In the case of the specification of the positive pressure of the pump, the pump liquid S is applied to the outer peripheral surface 1 of the one flange portion 110b of the elastic seal ring 110.
The sliding contact force of the 10d plate 109 on one side surface 109a is weakened, and the predetermined sealing performance in the boundary lubrication state cannot be maintained, and the pump liquid S enters the grease G from the sliding contact portion. , The properties of grease G change,
There is a problem that the sealing performance in the state of lubrication at the boundary surface by the grease G is further deteriorated.

FIG. 7 shows that the grease G is cooled by the centrifugal force caused by the high speed rotation of the rotating shaft 104, although the cooling effect on the elastic seal ring 110 is superior to that of FIG. It is inevitable that the sealing performance is deteriorated due to the outward movement in the radial direction, and the permissible shaft diameter peripheral speed is also limited to 3 m / sec. Besides, sleeve 1
Since 11 is used, the overall structure becomes complicated,
There was a problem that it took time and effort to assemble.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and does not complicate the structure, and seals the boundary between the elastic seal ring and the mating side by lubrication even at high speed rotation. Provided is a shaft sealing device that can constantly maintain performance in a stable manner, and that can prevent suction of air and mixing of a sealed liquid into a lubricant in both positive pressure and negative pressure specifications. The purpose is.

[0009]

To achieve the above object, according to the Invention The shaft seal device according to the present invention, to face fixed to the casing on the side wall of the casing rotating shaft to form a hole is penetrated, whereas A first elastic member fixed to the outer peripheral surface of the rotary shaft, having an annular plate whose side surface is in contact with the sealed liquid, and a flange portion having a vertical cross-sectional key shape, located between the side wall of the casing and the plate. A seal ring, having a flange portion having a hook-shaped vertical cross section, located on the sealed liquid side of the plate, in contact with the sealed liquid , fixed to the outer peripheral surface of the rotating shaft, and the outer peripheral surface of the outer peripheral portion of the collar portion is A second elastic seal ring slidingly in contact with the other side surface of the plate, wherein a lubricant is filled and supplied to a space surrounded by the rotating shaft, the plate and the two elastic seal rings.

[0010]

According to the present invention, the outer peripheral portions of the flange portions of the first and second elastic seal rings respectively fixed to the rotating shaft on both axial sides of the annular plate fixed to the casing so as to face the side wall of the casing. The outer surface is in sliding contact with both side surfaces of the plate, and the space surrounded by the rotating shaft, the plate and the two elastic seal rings is filled with the lubricant, so that centrifugal force acts on the lubricant when the rotating shaft rotates. Due to the force, the lubricant is always supplied to the sliding contact surfaces between the outer peripheral surfaces of the flange portions of the two elastic seal rings and both side surfaces of the plate, and the lubrication between the sliding surfaces is performed. The state is stably maintained, so that a predetermined sealing performance can be ensured even at the time of high-speed rotation.

Also, since one side surface of the second elastic seal ring and the annular plate on the side of the sealed liquid is in contact with the sealed liquid, the cooling effect on them is high, and the peripheral speed of the shaft can be increased. is there. Further, in the case of the positive pressure specification, the outer peripheral surface of the flange portion of the second elastic seal ring slidably contacts one side surface of the plate to prevent the sealed liquid from entering the lubricant filling space, and In the negative pressure specification, the outer peripheral surface of the flange portion of the first elastic seal ring slides strongly against the other side surface of the plate to prevent suction of air from the atmosphere. A predetermined sealing function can be reliably maintained for any of the specifications.

[0012]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a longitudinal sectional view of a shaft sealing device according to an embodiment of the present invention, in which 1 is a casing,
A rotating shaft 3 is provided in a rotating shaft through hole 2 formed in the side wall 1a.
Is inserted. Reference numeral 4 denotes an annular plate facing the side wall 1a, which is fixed to the pump liquid S side in the axial direction of the casing 1 via a stud 5 on the can M side. Reference numeral 6 denotes a rotary shaft through hole formed in the axis of the plate 4. Reference numeral 7 denotes an O-ring fitted to the annular concave portion 8 on the casing 1 side to seal a joint portion between the plate 4 and the casing 1, and 9 denotes an O-ring fitted to the annular concave portion 10 on the plate 4 side to This is an O-ring that seals a joint portion with M.

Reference numeral 11 denotes a first elastic seal ring disposed between the side wall 1a of the casing 1 and the plate 4, and reference numeral 12 denotes a first elastic seal ring disposed adjacent to the plate 4 on the pump liquid S side. This is a second elastic seal ring, and both elastic seal rings 11 and 12 are fixed to the outer peripheral surface of the rotating shaft 3 via drive bands 13 and 14, respectively.

The first elastic seal ring 11 is formed of NB
Ridges 11b and 11c having a longitudinal cross-section are provided at both ends in the axial direction of a cylindrical portion 11a made of rubber such as R, VISION, neoprene, hypalon, and EPR, or an organic elastic material such as fiber-reinforced rubber in which fibers are blended with them. It is integrally formed to have a substantially V-pulley shape.
The outer peripheral surface 11d of the casing 1b is elastically slidably in contact with one side surface 4a of the plate 4, and the outer peripheral surface 11e of the other flange portion 11c is in contact with the inner surface 1 of the side wall 1a of the casing 1.
b is lightly abutted.

The second elastic seal ring 12 is formed of NB
Ridges 12b and 12c are formed at the axial ends of a cylindrical portion 12a made of an organic elastic material such as rubber such as R, VISION, neoprene, hypalon, or EPR, or fiber-reinforced rubber obtained by mixing fibers with them. It is integrally formed to have a substantially V-pulley shape.
b, the outer surface 12d of the outer peripheral portion remains as it is,
The outer peripheral surface 12e of 2c is elastically slidably in contact with the other side surface 4b of the plate 4.

A space P surrounded by the rotating shaft 3, the plate 4, and the first and second elastic seal rings 11 and 12 is filled with grease G as a lubricant.
The grease G is supplied to the space P through a grease supply hole 15 formed in the plate 4.

Next, the operation of the shaft sealing device having the above configuration will be described. During normal operation of the pump, the first and second elastic seal rings 1
1, 12 rotate integrally. With this rotation, the first
The outer peripheral surface 11d of one flange 11b of the elastic seal ring 11 is in sliding contact with one side 4a of the plate 4, and the outer peripheral surface 11e of the other flange 11c is the inner surface 1b of the side wall 1a of the casing 1. And one flange portion 12c of the second elastic seal ring 12.
Outer peripheral surface 12e of the other side 4 of the plate 4
b.

At this time, the grease G filled in the space P has been moved radially outward by the centrifugal force, and the outer periphery of one of the flange portions 11b of the first elastic seal ring 11 has been moved. Pushing between the outer side surface 11d and the one side surface 4a of the plate 4 and between the outer peripheral surface 12e of the one flange portion 12c of the second elastic seal ring 12 and the other side surface 4b of the plate 4 respectively. In rare cases, a sealing function by boundary lubrication is provided between the two surfaces 11d, 4a and 12e, 4b, whereby the casing 1 and the rotating shaft 3 are sealed.

When the rotation speed of the rotating shaft 3 increases, the moving force of the grease G radially outward due to the centrifugal force increases, and the two surfaces 11d, 4a and 12e,
Since the supply of the grease G between the spaces 4b is promoted, the sealing function by the boundary lubrication is stably maintained. Further, since the second elastic seal ring 12 and the plate 4 are always in contact with the pump liquid S, they can be effectively cooled. Therefore, even if the peripheral speed of the shaft diameter is about 5 m / sec, the predetermined seal can be obtained. Performance can be maintained and sufficient response can be achieved.

In the case of the specification of the positive pressure of the pump, a state in which the outer peripheral surface 12e of the flange portion 12c of the second elastic seal ring 12 on the pump liquid S side comes into strong sliding contact with the other side surface 4b of the plate 4 is described. As a result, the sealing performance at the sliding contact portion is improved, and the pump liquid S
Is prevented from entering the filling space P. In the case of a negative pressure specification such as evacuation before starting the pump, the collar portion 11b of the first elastic seal ring 11 on the atmosphere A side is used.
The outer peripheral surface 11d of the plate 4 comes into sliding contact with the one side surface 4a of the plate 4 so that the sealing performance at the sliding contact portion is enhanced, and the suction of air from the atmosphere A side is effectively prevented. Is done.

Further, in the shaft sealing device having the above structure, the two elastic seal rings 11 and 12 are directly fixed to the outer peripheral surface of the rotating shaft 3. Since it is not necessary to use it at all and the structure can be simplified and the two-part structure is easy, the assemblability can be improved. The flange portion 11c of the first elastic seal ring 11 in this embodiment is used to prevent dust and foreign matter from entering the sliding contact portion between the outer peripheral surface 11d of the flange portion 11b and the plate. Depending on the situation,
It is also possible to select the first and second elastic seal rings without the flange portions 11c and 12b.

Hereinafter, an evaluation test of the sealing performance performed by the present inventors will be briefly described. FIG. 2 is a configuration diagram showing an outline of a device for a rotation test performed by applying the shaft sealing device to the shaft sealing of a horizontal shaft mixed flow pump. The test seal ring NS corresponding to the two elastic seal rings 11 and 12 is used.
And a dummy seal ring ND were prepared. The specifications of this pump are as follows. Fluid name: River water Pressure: 0 to -10 m (within 5 minutes, air and water) before operation During operation: 2.2 to -4.65 m (submerged in water) Temperature: room temperature Rotational speed: 442 rpm, peripheral speed: 3m / sec

In FIG. 2, reference numeral 21 denotes a test seal ring N
Rotary shaft 3 with S and dummy seal ring ND attached
Is a speed change motor for driving the rotary shaft 3. 23 is a pump for supplying the water W in the water tank 24 to the test seal ring NS and the dummy seal ring ND, 25 is a flow meter provided on the discharge side of the pump 23, and 26 is a sealed fluid as a lubricant. It is a pressure gauge.

The test conditions of the above rotation test device are as follows. Sealed fluid Water (grease reservoir) Sealed fluid temperature Normal temperature Sealed fluid pressure 0 to 20 m Rotational speed 442, 558, 738 rpm Flushing amount 3.0, 5.0, 10 l / min (with or without water supply) Available: Seal ring NS for test No flushing is performed from the side. No: Flushing is performed from the dummy seal ring ND side. Test time 30 to 150 min. Note that this test was performed with the expectation that the actual fluid would be agitated by the actual pump. No flushing.

With the test seal ring NS attached, the temperature of each part T1 to T6 shown in FIG. 3 was measured.

FIG. 4 shows a summary of the results of the above test. As shown in FIG. 4, no leakage of the encapsulated grease was observed throughout the entire test, and no leakage to the atmosphere was observed. further,
No abnormality was found in the seal surfaces of the test seal ring NS, plate and casing plate after opening.

Also, when the above test results were considered, it was determined whether the seal of the test seal ring NS could be used.
It is determined by the heat-resistant temperature of the material NBR, and the allowable use temperature is usually up to 60 ° C. Assuming that the working range is up to 60 ° C. or less, the test results show that the plate seal surface showing the highest temperature shows a shaft diameter peripheral speed of 3 m / sec.
c (the number of rotations 442 rpm) is in a sufficiently usable range. Further, if the flushing amount on the dummy seal ring ND side is secured at 10 l / min or more without water supply, the seal surface temperature is stabilized at around 550 ° C., but the peripheral speed is 4 m / s.
If it is set to ec, even if the flushing amount on the dummy seal ring ND side is 15 l / min or more without water supply, it will exceed 70 ° C. in several minutes and cannot be practically used.

On the other hand, when water is supplied from the test seal ring NS, the temperature temporarily rises to 49 ° C.
Keep within 40 ° C. Further, the shaft diameter peripheral speed is set to 5 m / sec.
There was no problem raising it to c. The test pressure is 5m
When the height is increased to 10,20m from the
It was confirmed that it could be used if it was 1 / min or more.

[0029]

As described above, according to the present invention, the first and second elastic seal rings respectively fixed to the rotating shaft on both sides in the axial direction of the annular plate fixed to the casing facing the side wall of the casing. The outer peripheral surface of the flange portion is configured to be in sliding contact with both side surfaces of the plate, and the rotating shaft, the plate and the space surrounded by the two elastic seal rings are filled with a lubricant.
Due to the centrifugal force at the time of rotation of the rotating shaft, the lubricant is constantly pushed and supplied to the sliding contact surfaces between the outer peripheral surfaces of the flange portions of both elastic seal rings and both side surfaces of the plate, and the boundary between the sliding contact surfaces is provided. A stable surface lubrication state can be ensured. Further, because the one side of the high temperature side second resilient seal ring and the annular plates are in contact with the sealed fluid, it is possible cooling effect on them also sufficiently exhibited. As a result, predetermined sealing performance can be stably ensured even during high-speed rotation. In other words, the usable peripheral speed of the shaft diameter can be increased without lowering the sealing performance.

In addition, in the case of the specification of positive pressure, the sealing function of the second elastic seal ring is enhanced to prevent the sealed liquid from entering the space filled with the lubricant. A predetermined sealing function can be reliably maintained satisfactorily for both positive pressure and negative pressure specifications, such that the sealing function of the sealing ring is enhanced to prevent the inhalation of air from the atmosphere. Furthermore, since the two elastic seal rings are directly fixed to the rotating shaft and the use of the sleeve is unnecessary, there is an effect that the structure can be simplified and the assemblability can be improved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional side view of a shaft sealing device according to an embodiment of the present invention.

FIG. 2 is a configuration diagram showing an outline of a seal ring rotation test device when the shaft sealing device is applied to the shaft sealing of a horizontal shaft mixed flow pump.

FIG. 3 is a longitudinal sectional view of a main part showing an arrangement of a temperature measuring portion with respect to a shaft sealing device when performing a rotation test.

FIG. 4 is a table summarizing test results.

FIG. 5 is a half-section longitudinal sectional view showing a conventional general gland packing type shaft sealing device.

FIG. 6 is a half-section longitudinal sectional view showing a conventional elastic seal ring air-cooled shaft sealing device.

FIG. 7 is a half-section longitudinal sectional view showing a conventional elastic seal ring water-cooled shaft sealing device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Casing 1a Side wall of casing 2 Rotating shaft through hole 3 Rotating shaft 4 Plate 4a, 4b Side surface of plate 11 First elastic seal ring 11b Collar portion of first elastic seal ring 12 Second elastic seal ring 12c Second Collar part 11d, 12e of elastic seal ring Outer peripheral surface of collar part G Grease (lubricant) P Space part

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F16J 15/32 311 F16J 15/34-15/36 F04D 29/10

Claims (1)

(57) [Claims] 1. A casing is fixed to a casing facing a side wall of the casing having a hole through which a rotating shaft is formed .
A first plate fixed to the outer peripheral surface of the rotary shaft, having an annular plate having a side surface in contact with the sealed liquid and a flange portion having a vertical cross-sectional key shape, located between the side wall of the casing and the plate.
With an elastic seal ring of
Positioned closer to the sealed liquid than the above plate and in contact with the sealed liquid
A second elastic seal ring fixed to the outer peripheral surface of the rotating shaft and having the outer peripheral surface of the collar slidingly in contact with the other side surface of the plate; the rotating shaft, the plate, and both elastic seals; A shaft sealing device characterized in that a lubricant is filled and supplied into a space surrounded by a seal ring.