JPS60148996A - Seal apparatus in large caliper rotary drilling machine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sealing device for a rotary excavator such as a shield excavator, a horizontal hole excavator, or a vertical hole excavator that excavates the ground under high water pressure, and particularly for a large-diameter rotary excavator. The present invention relates to a sealing device.

A shield excavator, which is one of the large-diameter rotary excavators, will be explained with reference to FIG. This shield excavator has a cutter wheel 1 rotatably supported through a bearing 10 at the front opening of the shield body. Support bulkhead 13 of the shield body 2
A drive motor 12 is fixed to the drive motor 12, and a swing ring 19 is provided on the power lever wheel 1, and a pinion 1 fixed to the rotating shaft of the drive motor 12 is meshed with the swing ring 19. Between the inner circumferential surface of the large diameter cylindrical portion 2a of the shield body 20 and the outer circumferential surface of the large diameter cylindrical portion 1a of the cutter wheel 1, which face each other, and between the outer circumferential surface of the small diameter cylindrical portion 2b of the shield body 2 and the small diameter of the cutter wheel 1. A cutter seal 3a+ is placed between the inner circumferential surface of the cylindrical portion 1b.
4a, 5m+3b+4b+5b are interposed. (7) Cutter seals 3a, 4a, 5a, 3b+4b, 5b are:
This is a multi-lip seal with a long lip length. The drive motor 12 is driven to rotate the cutter wheel 1 to excavate the ground. Note that A in the figure indicates the pressure inside the shield body 2, that is, the atmospheric pressure. B indicates the face, which is under high water pressure and high earth pressure. C indicates a binion chamber containing the binion 11 and the like, and D indicates a bearing chamber containing the bearing 10 and the like.

As shown in FIG. 2, a conventional sealing device for such a large-diameter rotary excavator includes a multi-lip seal 3 (3al, 3b) between the shield body 2 (2a, 2b) and the cutter wheel 1 (1a, 1b). ) + 4 (4a.

4b) and 5 (5a, 5b), for example, three. The oil sump chamber in the space between these three multi-lip seals 3, 4.5, the first oil sump chamber E in the space between the seals 3 and 4, and the space between the seals 4 and 5. The grease pump 14 of the pressure fluid supply device is installed in the second oil reservoir chamber F in the space of
Connect the feed routes from each. This conventional sealing device supplies grease from a grease pump 14 to a first oil reservoir chamber E and a second oil reservoir chamber F via a supply path, and the first oil reservoir chamber E and the second oil reservoir chamber The pressure of F PI + PI is the same,
Furthermore, the water pressure Pw on the face B side is maintained to be approximately equal to the water pressure Pw to prevent excavated earth and sand from entering the shield body 2. Since such a conventional sealing device uses a multi-lip seal 3.4.5, it has the following advantages:

(1) When the lip length is long, the elastic deformation caused by the water pressure f of a large-diameter structure can be easily followed, and the sealing performance is stable.

Even if the amount of deflection of the seal changes, the seal lip contact pressure changes little and the sealing performance remains unchanged.

(2) Even if the hair ring is worn and the amount of eccentricity between the shield body and cutter foil increases, the eccentricity can be followed well and the sealing performance is stable.

(3) When the seal height is large, the gap between the opposing cylindrical portions of the cutter foil and the shield body is large, making centering work easier when fitting and assembling large-diameter heavy structures.

(4) In large-diameter structures, it is technically difficult to perform surface hardening treatment (quenching, chrome plating, etc.) on the seal sliding surface, so the surface hardness is low and therefore easily abraded by muddy water. , it is easy to prevent the invasion of earth and sand by dividing it into each stage.

However, in the conventional sealing device, grease is supplied to the first oil reservoir chamber E and the second oil reservoir chamber F, and the pressure Pl of the first oil reservoir chamber E and the pressure P1 of the second oil reservoir chamber F are adjusted. Since the pressures are controlled to be the same, if the oil pressure P on the back side of seals 3 and 4 becomes higher than the water pressure Pw on the face B side, grease will naturally leak out to the face B side, and the seal 3 and seal The pressure P in the first oil reservoir chamber E between the seals 4 and 5, and the pressure P1 in the second oil reservoir chamber F between the seals 4 and 5 are both at the face B.
It is almost equal to the side water pressure Pw. Therefore, the pressure difference at the seal 5 closest to the atmospheric pressure Po side of the shield body 20 is Pw
-P6 = Pw -0= Pw is almost equal to the water pressure Pw on the face B side, and as a result, the pressure resistance of the conventional sealing device is as follows: -P6 = Pw -0 = Pw It depends directly on the pressure resistance performance.

However, this multi-lip type has a long lip length, so it has low pressure resistance and cannot withstand high water pressure. Therefore, the conventional sealing device described above has the disadvantage that it is not suitable for sealing under high water pressure.

One way to improve pressure resistance is to increase the rigidity by shortening the lip length and increasing the lip thickness, but this proposal loses the advantages mentioned above and also causes eccentricity and elastic deformation of the cutter foil. At times, the contact pressure of the seal lip increases rapidly, resulting in faster wear and shorter seal life. Another option for improving pressure resistance is to use glue with an iron reinforcing ring, but apart from small-diameter ones that are rigid and not difficult to handle and can be handled by hand, large-diameter ones are difficult to handle due to lack of rigidity. There are deficiencies such as difficulty in transportation and difficulty in centering during assembly. Note that Dem's seals can be folded and transported. In addition, there is a plan to improve pressure resistance using a back love ring, but in this plan, high water pressure is ultimately transmitted to the gland, and the clearance S between the gland ring and the sliding surface of the gland prevents the protrusion phenomenon. It needs to be small. For this reason,
When assembling a large-diameter structure, centering work becomes difficult, and due to eccentricity or elastic deformation of the cutter wheel, the clearance S becomes O, resulting in contact with each other and galling. The object of the present invention is to provide a sealing device for a large-diameter rotary excavator that does not have the above drawbacks, can withstand high water pressure, and has a long life.

The present invention forms a plurality of pressure chambers behind a multi-lip seal interposed between an excavator body and a rotary excavator, and connects each pressure chamber with a feed path from a pressure fluid feed device. The pressure in one of the plurality of pressure chambers is maintained at the same pressure as the water pressure at the face, and the pressure in the next pressure chamber is sequentially reduced by 20 degrees to maintain a predetermined pressure. It is characterized by pressure control.

Three examples of the sealing device for a large-diameter rotary excavator according to the present invention will be described below with reference to FIGS. 4 to 6.

FIG. 4 is a partial sectional view showing a first embodiment of the sealing device of the present invention.

In the figure, the same reference numerals as in FIGS. 1 and 2 indicate the same parts.

Therefore, the sealing device of the present invention in this embodiment is as follows:
Shield body 2 (2a, 2b) and cutter wheel 1
(Ia, lb) Multi-lip type seal 2 interposed between
Similarly, two multi-lip seals n and 23 are installed behind the pressure chambers G and H to form two pressure chambers G and H. That is, the first
The pressure chamber G is formed between the seal 2 near the water pressure Pw on the first shield body side and the intermediate seal 22, and the second pressure chamber H is formed between the intermediate seal N and the atmospheric pressure Po side of the first shield body 2. A close seal forms between the two. This first pressure chamber G, the second
The first grease pump 14a and the second dalis in the pressure chamber H? The feed paths 20a and 2flb from the ring 14b are connected to each other.

The sealing device of the present invention in this embodiment has the above configuration, and its operation will be explained below.

Grease is supplied from the first grease pump 14a to the first pressure chamber G via the feed path side a;
Grease is supplied to the second pressure chamber H via the supply path 2flb, and the pressure P2 of the first pressure chamber G is maintained at the same pressure as the water pressure Pw at the face B (ljl), and the pressure P3 of the second pressure chamber H is The pressures are controlled so as to maintain them at one half of the pressure difference between the pressure P2 in the first pressure chamber G and the atmospheric pressure Po on the side of the shield body 2.

As a result, multiple lip type seals 2], 22, 23
It is possible to take advantage of the advantages of the above, and also achieve effects such as being able to withstand high water pressure.

Here, the sealing performance of the sealing device of the present invention and the conventional sealing device will be explained in more detail by citing specific numbers. In addition, multiple lip type seals 3, 4, 5, 21
, 22. The pressure resistance of 23 is assumed to be 5 kg/lri.

Mass, in conventional sealing equipment, greasepon 7”1
Grease is supplied from 4 to the first oil reservoir E and the second oil reservoir F through 20 on the feed path side, and the pressure P1 in the first oil reservoir chamber E and the pressure in the second oil reservoir F are Same as P1 5 kg/
I keep it in cJ. As a result, it can only withstand water pressure of 5 kg/cm.

On the other hand, in the sealing device of the present invention, the second pressure chamber H is supplied with grease from the second grease pump 14b.
The pressure P3 of the first pressure chamber G to which grease is supplied from the first grease pump 14a is maintained at 10 kg/ctrl. As a result,
It can withstand water pressure of 10kg/c4, twice as much as conventional sealing devices. Moreover, at the intermediate seal n, the pressure P2 in the first pressure chamber G and the pressure P3 in the second pressure chamber H
The differential pressure between the pressure P3 in the second pressure chamber H and the atmospheric pressure Po in the shield body 2 is 5 kg/cr+l in the seal B near the atmospheric pressure Po side of the shield body 20. ctrl and is equal to the differential pressure at seal 5 of the conventional sealing device. Therefore, in the sealing device of the present invention, the contact surface pressure of the shield body can be made the same as that of the conventional sealing device. The advantage of this is that the life of the cutter seal can be extended. It is said that the amount of wear on the seal sliding surface is proportional to the product of the seal lip contact surface pressure and the sliding distance, so the fact that the contact surface pressure is the same as before means that despite the high water pressure. It can be assumed that the wear life is the same as that of conventional sealing devices.

In addition, when the water pressure Pw on the face B side is 5 kg/cJ, the differential pressure at the seal 5 near the No. 1 shield body 20 atmospheric pressure po side of the conventional sealing device is 5 k which is equal to the water pressure.
g/c4. Accordingly, the sealing device of the present invention controls the pressure to maintain the pressure P2 in the first pressure chamber E at 5 kg/cJic and the pressure P3 in the second pressure chamber F at 2.5 kg/l and rl, respectively. Therefore, the differential pressure at the intermediate seal 22 is 2.5 kg/J, and the differential pressure at the seal B near the atmospheric pressure Po side of the No. 1 shield body 2 is 2.5 kg/J.
5 kg/crl. Therefore, for the same water pressure, the sealing device of the present invention can cope with a differential pressure that is one-half that of the conventional sealing device. Since the differential pressure can be reduced in this way, the amount of wear is reduced and the life of the seal is extended.

FIG. 5 is a partial sectional view showing a second embodiment of the sealing device of the present invention.

The sealing device of the present invention in this embodiment is the first sealing device described above.
In the embodiment, a labyrinth seal 24 for maintaining pressure made of the same elastic material as the sealing material is inserted in place of the seal B closest to the pressure side of the multiple lip seals in the embodiment, and a labyrinth seal 24 between the labyrinth seal 24 and the intermediate lip seal Lip type seal 2
A second pressure chamber H is formed between the near compressor 15 and the second pressure chamber H, and the air supply path 5 from the near compressor 15 is connected to the second pressure chamber H.

In this embodiment, the pressure P1 in the first pressure chamber G is
The pressure is maintained at the same pressure as the water pressure Pw on the side, and the second pressure chamber H
The above-mentioned first embodiment It is possible to achieve the same effect as that of .

FIG. 6 is a partially sectional view showing a third embodiment of the sealing device of the present invention.

The sealing device of the present invention in this embodiment is the first sealing device described above.
In this embodiment and the second embodiment, instead of the multi-lip seal and the labyrinth seal 24 on the atmosphere side, a pressure-tight sealing bulkhead 6 provides a second seal in the binion chamber C and the bearing chamber.
A pressure chamber H is formed, and an air supply pipe 5 from a near compressor 15 is connected to the second pressure chamber H. This embodiment can also achieve the same effects as those of the first and second embodiments described above.

In addition, in the above-mentioned embodiment, the multiple lip type seal 2
Two pressure chambers G and H are formed at the rear of the pressure chamber 1, but if there are three or more pressure chambers, the pressure chamber can withstand high water pressure accordingly.

As is clear from the above embodiments, the sealing device of the present invention can achieve the following effects.

1. The pressure resistance of the large-diameter seal at high water pressure has been greatly improved.

2. The seal structure is suitable for any water pressure fluctuation from low to high water pressure by simply controlling the pressure of the intermediate pressure chamber without changing the seal shape. 3. Even at high water pressure, the -knoll lip contact surface The pressure can be kept constant by adjusting the lip differential pressure, so
Even when water pressure fluctuates, optimal contact pressure can always be maintained.
The wear rate of the seal sliding surface and seal lip can be reduced, resulting in a longer seal life.

4. Since a low-pressure seal and a lug-shaped seal can be used, the mold for producing the seal can be shared, making it economical.

[Brief explanation of the drawing]

Figure 1 is a secondary sectional view showing a shield excavator in a large-diameter rotary excavator, Figure 2 is a partial sectional view showing a conventional sealing device, and Figure 3 is a conventional backup ring type sealing device. FIG. 4 to 6 show an embodiment of a sealing device for a large-diameter rotary excavator according to the present invention, FIG. 4 is a partial sectional view showing a first embodiment of the sealing device of the present invention, and FIG. The figure is a partial sectional view showing a second embodiment of the sealing device of the invention, and FIG. 6 is a partial sectional view showing a third embodiment of the sealing device of the invention. 1... Cutter foil, 2... Shield body, 6...
...m M F% 11! , 11... Ginion, 1
2... Drive motor, 14° 14a, 14b... Grease pump, 15... Air conditioner compressor, 19...
・Swivel ring, 20, 2IIa, 2rIb...Feeding path, 2
1, 22゜O...Multiple lip type seal, Hime...Labyrinth type seal, 5...Pressure air path, A...Inside the shield body, B...Face, C...Binion chamber, D ...
Bearing chamber, G...first pressure chamber, H...second pressure chamber. Patent Applicant Hitachi Construction Machinery Co., Ltd. Representative Patent Attorney Tadashi Akimoto Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] 1. A rotary excavator is rotatably supported on an excavator body, a multi-lip seal with a long lip length is interposed between the excavator body and the rotary excavator, and the rotary excavator In a large-diameter rotary excavator that excavates the ground by rotating a tool, a plurality of pressure chambers are formed behind the multi-lip seal between the excavator main body and the rotary excavator, and each pressure chamber is filled with pressure. The feeding paths from the fluid feeding device are connected to each other, and the pressure in the pressure chamber closest to the face among the plurality of pressure chambers is maintained at the same pressure as the water pressure at the face, and the pressure in the next pressure chamber is sequentially increased. A sealing device for a large-diameter rotary excavator, characterized in that the pressure is controlled to reduce the pressure and maintain it at a predetermined pressure. 2. The sealing device for a large-diameter rotary excavator according to claim 1, wherein the pressure chamber is constituted by a multi-lip seal with a long lip length. 3. 2. A sealing device for a large-diameter rotary excavator according to claim 1, wherein the pressure chamber is constituted by a pressure holding member extending from an elastic member. 4. The sealing device for a large-diameter rotary excavator according to claim 1, wherein the pressure chamber is constituted by a sealing partition.