JP2598204B2 - Cutter frame of groove wall drilling cutter with pressure compensation device for bearing seal - Google Patents

Abstract

A cutting frame for a trench cutter with oil-lubricated bearing seals for the cutter wheels and with a controlled hydraulic pressure-compensation device for the bearing seals is described. There is a pressure-resistant oil reservoir connected to the bearing seals via lines and there is an air-filled buffer space open at the bottom, exposed to the outside pressure and arranged vertically below the oil reservoir. The oil reservoir and the buffer space are connected to one another via a longitudinally displaceable piston, and the piston is preloaded by a compression spring in the direction of the oil reservoir. <IMAGE>

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil-lubricated bearing seal for a cutter drum and a cutter frame of a groove wall excavating cutter provided with an adjustable hydraulic pressure compensating device for the bearing seal.

[0002]

2. Description of the Related Art A trench wall excavating cutter has an underground structure of 100 m.
Used to create grooves that can be as deep as Until the diaphragm wall is formed, the grooves are filled with a stabilizing liquid consisting of a mixture of bentonite and water. Since the hydraulic pressure increases as the depth increases, the bearing seal of the cutter drum must be equipped with a pressure compensator in order to prevent penetration or leakage of the stabilizing liquid and oil loss. With known pressure compensators, it has been difficult to supply the pressure inside the bearing seal correspondingly rapidly when there is a sudden change in depth or a sudden change in pressure in the cutter frame.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a cutter frame provided with a pressure compensating device of the above-mentioned type, which can reliably perform pressure compensation even when a sudden pressure change occurs. is there.

[0004]

In order to achieve this object,
The present invention provides a bearing seal with oil pressure
A reservoir is connected, and a buffer chamber is provided vertically below the oil reservoir and opens downward, is filled with air and pressurizes to the outside, and the oil reservoir and the buffer chamber are arranged in a longitudinal direction. Interconnected by a movable piston, which is preloaded with a compression spring in the direction of the oil reservoir.

[0005]

The invention is based on the provision of a preload spring, which on the one hand produces a certain constant overpressure in the oil reservoir and therefore in the bearing seal, and on the other hand prevents leakage losses. It has the advantage of being able to. If the external pressure increases sharply, there is no possibility for the stabilizing liquid to penetrate, even if the piston is deflected with a time delay or not so fast, for example due to stiction. This important and sensitive area is protected from contamination since the compressed air in the buffer chamber acts as a medium separating the stabilizer and the moving parts of the pressure compensator.

According to a preferred embodiment of the invention, the compression spring is helical, the helical compression spring being located on the piston, one end of which is on the flange of the piston casing and the opposite end of the piston. Supported on shoulders.

[0007] Particularly easy guidance is achieved in that the piston is provided with a bush on the side facing the oil reservoir and the compression spring is located between the piston and the bush.

In particular, it is expedient if the free end of the bushing has a base, on which the corresponding end face of the piston engages from inside. A bush capable of performing all such piston movements, together with the rolled diaphragm, constitutes an easily sealable movable closure for the oil reservoir.

Hollow pistons to reduce weight and improve upward pressure help rapid readjustment.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to embodiments with reference to the accompanying drawings.

Referring to FIG. 1, the trench wall cutting cutter includes a rail-guided trolley (or carriage) 10 having a bracket 11 on which a support frame 14 supports a cutter frame 12. ing. On the cutter frame 12, two pairs of cutter drums 1 are provided.
3 are provided and these cutter drums are driven by a hydraulic motor. The slot 15 is filled with a stabilizing solution comprising a water / bentonite mixture.

A pressure compensator 16 is provided on the cutter frame 12.
The pressure compensator is connected to an oil-lubricated bearing seal (not shown) of the cutter drum 13 by a pipe line. The pressure compensator 16 re-adjusts the oil pressure in the bearing seal as a function of the external pressure in the stabilizing liquid so that no oil flows out of the bearing and no stabilizing liquid enters the bearing.

As shown in FIG. 2, the pressure compensator 16 includes a counter-pressure oil reservoir 17, an air-filled buffer chamber 18, and a vertically displaceable piston 19. The piston 19 and the oil reservoir 17 are installed in a cylindrical casing 20.
This casing is attached to the cutter frame 12 with the mounting support 2.
1 (Fig. 1). A cylindrical body 22 is provided surrounding the buffer chamber 18, and the cylindrical body
0, and is fixed to the cutter frame by screws 23.

The oil reservoir 17 has a first opening 24 for connection to a hose line, which opens to a pressure gauge (not shown). The oil reservoir can be filled or refilled through a second closable second opening 25. A third opening 26 is used for connecting a hose to a bearing seal (not shown).

The oil reservoir 17 includes a casing 20
On the one hand, bounded on the one hand by an extension 27 of the cylinder cover housing the piston 19 and, on the other hand, by a container 28 of the same length with a front flange. At the connection point between the container 28 and the extension 27, a roll-shaped diaphragm 29 is fixed, and this roll-shaped diaphragm connects the oil reservoir 17 to the piston 1.
9 and seal against piston guide.

The vertically displaceable piston 19, which is constructed as a hollow body, acts on the oil reservoir 17 on the front surface of a large area thereof, so that the displacement of the piston causes a pressure change. The piston displacement starts when the stabilizing liquid applies a pressure corresponding to the free end of the piston 19 near the buffer chamber 18 when the cutter frame is lowered or raised.

The piston 19 is preloaded on the oil reservoir 17 by a helical compression spring 30. Therefore, the internal pressure of the oil reservoir 17 is
This is the sum of the external pressure in the slot 15 (FIG. 1) and the preload by the compression spring 30. By appropriately selecting the length or the amount of displacement of the compression spring 30, the elasticity can be kept constant over a predetermined distance.

A compression spring 30 surrounding the piston 19
Are supported on a ring-shaped flange 31 on the free end face of the casing 20. A ring-shaped shoulder 32 for supporting the compression spring 30 is formed as a portion corresponding to the piston 19.

In the casing 20, a bush 33 is mounted on the piston 19, and this bush is
And a compression spring 30 is provided between the bush 33 and the piston 19. The piston 19 and the compression spring 30 are not in contact with the casing wall. By choosing the material of the bush accordingly, easy piston guidance can be achieved. The bush 33 also has a base 34 on which the end face of the piston 19 is supported. The base 34 also supports the roll-shaped diaphragm 29.

The buffer chamber 18 contains air bubbles, so that no stabilizing liquid passes between the moving parts, in particular into the piston guide.

[0021]

According to the present invention, it is possible to provide a cutter frame having the above-described pressure compensating device and capable of reliably performing pressure compensation even when a sudden pressure change occurs.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view of a trench wall cutting cutter.

2 is a longitudinal sectional view through a pressure compensating device for bearing seals of the cutter frame of the groove wall excavating cutter of FIG. 1;

[Explanation of symbols]

 10 trolley 11 bracket 12 cutter frame 13 cutter drum 14 support cable 15 slot 16 pressure compensation device 17 ··· Oil reservoir 18 ··· Buffer chamber 19 ··· Piston 20 ··· Casing 21 ··· Mounting support 22 ··· Cylinder 23 ··· Screw 24 ··· 1st opening 25 ... 2nd opening 26 ... 3rd opening 27 ... Extension part 28 ... Container 29 ... Diaphragm 30 ... Compression spring 31 ... Flange 32 ・ ・ ・ ・ ・ ・ Shoulder 33 ・ ・ ・ ・ Bushing

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Ignas Seytle Germany D-8859 Carl Schuld Carl-Von-Ecarto-Strasse 20

Claims (5)

(57) [Claims] 1. An oil-lubricated bearing seal for a cutter drum and a cutter frame of a groove wall drilling cutter provided with an adjustable hydraulic pressure compensation device for the bearing seal, comprising a bearing seal having a pressure-resistant oil reservoir through a conduit. 17), and a buffer chamber (18) which opens downward and is filled with air and pressurized to the outside is provided vertically below the oil reservoir (17). The reservoir (17) and the buffer chamber (18) are interconnected by a longitudinally displaceable piston (19), which is moved by a compression spring (30) in the direction of the oil reservoir (17). A cutter frame which is preloaded. 2. The cutter frame according to claim 1, wherein the compression spring (30) has a spiral shape and the piston (19).
It is characterized in that one end of this helical compression spring is supported on the flange (31) of the casing (20) of the piston and the opposite end is on the shoulder (32) of the piston (19). Cutter frame. 3. The cutter frame according to claim 1, wherein a piston (1) is provided on a side facing the oil reservoir (17).
9) A cutter frame comprising a bush (33), wherein the compression spring (30) is located between the piston (19) and the bush (33). 4. The cutter frame according to claim 3, wherein the free end of the bush (33) comprises a base (34), on which the corresponding end face of the piston (19) engages from inside. Features a cutter frame. 5. The cutter frame according to claim 1, wherein the piston (19) is hollow.