JP4248370B2 - Shield excavator and its cutter bit replacement method - Google Patents

Description

  The present invention relates to a shield excavator used for a shield method and a cutter bit replacement method thereof.

As shield construction becomes longer, it has become necessary to replace the cutter bits worn by excavation of natural ground during construction.
As this exchange method, there are a method in an intermediate shaft excavated from the ground surface, and a method in which an operator goes out of the shield excavator and exchanges directly.
In order to simplify this replacement work, a method has been proposed in which a spare cutter bit is attached in advance to a cutter pork and the cutter pork is rotated to replace it with a new bit (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 2003-176691

The exchanging method for excavating intermediate shafts has been difficult to construct in the case of large cross-section construction or deep underground construction.
In addition, in the method in which the worker goes out of the shield excavator and exchanges directly, it is necessary to provide a working space in front of the shield excavator and to inject stable liquid into the ground to stabilize the face.
These methods required many costs and a long construction period.

In a conventional shield excavator that rotates a cutter pork and replaces the cutter bit, the cutter bit bites into an unexcavated ground portion during rotation, resulting in resistance to rotation.
For this reason, it has been necessary to increase the torque of the hydraulic motor that rotates the cutter pork or to rotate the cutter pork after slightly retracting the shield excavator.

  An object of the present invention is to facilitate rotation of a cutter pork in a shield excavator that rotates a cutter pork to replace a cutter bit.

In order to solve the above problems, the invention described in claim 1 includes, for example, a cutter head 3 rotatably attached to a distal end portion of a body 2 as shown in FIGS.
A cylindrical cutter pork 5 provided on the cutter head 3 and provided with a cutter bit 6 for excavating natural ground on its peripheral surface, and by rotating the cutter pork 5 about its axis, In the shield excavator 1 in which the cutter bit 6 is replaceable,
A cutter bit 6 movably assembled along the radial direction of the cutter pork 5;
A biasing means 8 for constantly biasing the cutter bit 6 in a direction in which the cutter bit 6 is housed in the cutter pork 5;
Extruding means 9 provided in the cutter pork 5 and having a protruding portion 11 for extruding the cutter bit 6 out of the cutter pork 5 from a state accommodated in the cutter pork 5;
Provided on the outer peripheral surface facing the cut face of the cutter pork 5 is provided with a leading bit 7 having the tip portion arranged outside the locus drawn by the tip portion of the cutter bit 6 housed when the cutter pork 5 is rotated. It is characterized by that.

As described above, in addition to the cutter bit 6 being assembled movably along the radial direction of the cutter pork 5, the cutter bit 6 is provided with an urging means 8 that constantly urges the cutter bit 6 in a direction in which the cutter bit 6 is accommodated inside the cutter pork 5. Thus, the cutter bit 6 can be kept in a state where it is always accommodated in the cutter pork 5 except during use, and wear due to friction with the excavated earth and sand can be prevented.
Furthermore, by providing the extrusion means 9 for pushing out the cutter bit 6, only the cutter bit 6 necessary for excavation can be projected from the outer peripheral surface of the cutter pork 5.
In addition, by providing the leading bit 7 with the tip arranged outside the locus drawn by the tip of the stored cutter bit 6, it is possible to excavate the natural ground portion that the cutter bit 6 has bite into when the cutter pork 5 rotates. The resistance at the time of rotating the katspoke can be reduced.

The invention according to claim 2 is a method of exchanging the cutter bit in the shield excavator according to claim 1, for example, as shown in FIG. 3 and FIG. A first step of releasing the extrusion and accommodating the cutter bit 6 in the cutter pork 5;
A second step of rotating the cutter pork 5 and directing the outer peripheral portion of the cutter pork 5 from which the cutter bit 6 protrudes toward the face side;
And a third step of extruding the cutter bit 6 by the extruding means 9.

  By exchanging the cutter bit 6 in such a procedure, the cutter bit 6 does not bite into the ground when the cutter pork 5 rotates, and the cutter pork 5 can be easily rotated.

According to the first aspect of the present invention, only the cutter bit necessary for excavation can be protruded from the cutter pork, and wear of the unused cutter bit can be prevented.
Further, by excavating a natural ground portion through which the cutter bit passes when the cutter pork is rotated by the preceding bit, it is possible to reduce the resistance during the rotation of the cutter pork.

  According to the second aspect of the present invention, the cutter bit does not bite into the natural ground during the rotation of the cutter pork, and the rotation of the cutter pork becomes easy.

Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.
As shown in FIG. 1, the shield excavator 1 includes a cylindrical body 2 and a circular cutter head 3 that abuts the face.
A drive shaft (not shown) is provided at the center of the cutter head 3 on the body 2 side, and is driven by a hydraulic motor (not shown) to rotate the cutter head 3 and excavate natural ground.

As shown in FIG. 1 (A), a slit 22 is formed on the surface of the cutter head 3 that is in contact with the face of the cutter head 3 from the approximate center of the cutter head 3 to the outer peripheral portion along the radial direction.
A total of four slits 22 are formed every 90 degrees in the circumferential direction of the cutter head 3, and a cutter pork 23 having a plurality of fixed cutter bits 24 is provided therein.

Further, between the slits 22, slits 4 having a length approximately half that of the slits 22 are formed along the radial direction of the cutter head 3.
A total of four short slits 4 are formed every 90 degrees in the circumferential direction of the cutter head 3.
That is, the short slits 4 and the long slits 22 are alternately formed every 45 degrees in the circumferential direction of the cutter head 3.
The short slit 4 is provided with a cylindrical cutter spoke 5 that allows the cutter bit 6 to be exchanged by rotating about its axis.
Since the shield excavator 1 has the same configuration as the well-known shield excavator except for the configuration of the cut spoke 5, only the configuration and function of the cut excavator 5 will be described in detail below.

As shown in FIG. 2 or FIG. 3, the cutter pork 5 has a quadrangular cylindrical section, and includes a cutter bit 6 and a leading bit 7 on the outer peripheral surface thereof.
As shown in FIG. 3B, the cutter bit 6 is arranged at the corner of the cutter pork 5 so as to have a length direction along the radial direction of the cutter pork 5.
The cutter bit 6 is movable with respect to the cutter pork 5 along its length direction. The movable range of the cutter bit 6 is from the position where the tip end portion of the cutter bit 6 protrudes from the outer peripheral surface of the cutter pork 5. It is up to the position accommodated in.

An urging means 8 is provided in the vicinity of the bottom 10 of the cutter bit 6.
The urging means 8 has a compression spring inside, and constantly urges the bottom portion 10 of the cutter bit 6 toward the center of the cutter pork 5.
Thereby, the unused cutter bit 6 can be accommodated in the cutter pork 5, and wear due to friction with the excavated earth and sand can be prevented.

A leading bit 7 is provided on each face facing the face of the cutter pork 5.
As shown in FIG. 4B, the leading end portion of the preceding bit 7 is outside the locus drawn by the leading end portion of the cutter bit 6 accommodated when the cutter spoke 5 is rotated.
By excavating the portion through which the tip of the cutter bit 6 passes with the preceding bit 7, the cutter bit 6 does not bite into the ground when the cutter pork 5 rotates.

As shown in FIG. 3A, the push-out means 9 is provided at the center of the cutter pork 5 and includes a protrusion 11 that abuts against the bottom 10 of the cutter bit 6, and the center axis 12 of the cutter pork 5. , And a tubular portion 13 that can freely move along a hydraulic jack 14 that can be extended and retracted.
The hydraulic jack 14 is inside the central shaft 12 of the cutter spoke 5, and one end of the hydraulic jack 14 is attached to a fixing portion 15 of the cutter spoke 5 to the cutter head 3.
The other end of the hydraulic jack 14 is attached to the cylindrical portion 13 through an opening 17 provided on the side surface of the central shaft 12 of the cutter spoke 5.

The cylindrical portion 13 has the central shaft 12 of the cutter spoke 5 inserted therein and is connected to the hydraulic jack 14 as described above.
The projecting portion 11 is provided on the face side of the cylindrical portion 13, and the shape thereof is a wedge shape with one side as an inclined surface as shown in FIG. ), The shape can be brought into contact with the bottom portions 10 of the two cutter bits 6 at the same time.
As shown in FIG. 3A, the arrangement of the protrusions 11 corresponds to the attachment position of the cutter bit 6, and there are a plurality of protrusions 11 arranged along the length direction of the cutter pork 5 on the face side. The cutter bits 6 can be pushed out simultaneously.
Further, as shown in FIG. 4A, the protruding portion has such a length that the protruding portion 11 is retracted from the bottom portion 10 of the cutter bit 6 and accommodated between the cutter bits 6 when the cutter bit 6 is accommodated. .

As shown in FIG. 2, a motor 18 that rotates the cutter pork 5 is attached to the fixed portion 16 of the rotatable cutter pork 5 on the center side of the cutter head 3.
An output shaft (not shown) of the motor 18 is connected to the cutter spoke 5 directly or via a speed reducer or the like.
Further, the fixed portion 16 is provided with a stopper jack 19 that prevents rotation of the cutter pork 5 except when the cutter bit 6 is replaced during excavation or the like.
The stopper jack 19 has a pin 20 movable along the length direction of the cutter pork 5, and an engaging portion 21 into which the pin 20 is inserted is provided on the movable portion of the cutter pork 5. Yes.

Next, a method for replacing the cutter bit 6 of the shield excavator 1 configured as described above will be described with reference to FIGS.
The position of the face in FIGS. 3 and 4 is in the upper part of the figure.

The shield excavator 1 excavates natural ground by the same method as the conventional shield excavator.
When excavation is performed to some extent, the excavation efficiency of the shield excavator 1 decreases due to the wear of the cutter bit 6 and the change in soil quality.
When this occurs, the cutter bit 6 is exchanged.

During excavation, as shown in FIG. 3A, the hydraulic jack 14 of the push-out means 9 is extended so that the protrusion 11 comes to a position where the bottom 10 of the cutter bit 6 is pushed up. Suppose that 6 protrudes from the cutter pork 5.
Further, the unused cutter bit 6 is kept in the state where the cutter pork 5 is accommodated by the biasing means 8.
As shown in FIG. 2, the stopper jack 19 fixes the cutter spoke 5 with the pin 20 inserted into the engagement portion 21 of the cutter spoke 5.

After the shield excavator 1 is stopped and the excavation is stopped, the hydraulic jack 14 is retracted and the protrusion 11 is retracted from the bottom 10 of the cutter bit 6 as shown in FIG.
The cutter bit 6 is urged toward the center of the cutter pork 5 by the urging means 8, so that it is accommodated inside the cutter pork 5.

Next, the pin 20 of the stopper jack 19 is pulled out from the engaging portion 21 and the fixing of the cutter pork 5 is released. Then, the motor 18 is driven to rotate the cutter pork 5 180 degrees, and the cutter bit 6 to be used next is cut. Turn to the side.
At this time, the portion of the face where the tip of the cutter bit 6 passes is already excavated by the preceding bit 7, so that the cutter bit 5 can be easily rotated without the cutter bit 6 biting into the face during rotation.

When the rotation of the cutter pork 5 is completed, the cutter pork 5 is fixed by the stopper jack 19.
Thereafter, as shown in FIG. 3A again, the hydraulic jack 14 of the push-out means 9 is extended, and the bottom 10 of the new cutter bit 6 is pushed up by the projecting portion 11, and the cutter bit 6 is removed from the cutter pork 5. Protrude and resume drilling.

In the above embodiment, the cross-sectional shape of the cutter pork 5 is a quadrangle, but the present invention is not limited to this, and may be other shapes, for example, a polygon such as a hexagon or a circle. .
Further, the mechanisms of the biasing means 8 and the pushing means 9 are not limited to those shown here, and other mechanisms may be used.
Furthermore, the number of cutter bits 6 to be attached is arbitrary, and it is needless to say that other specific detailed structures can be appropriately changed.

It is the (A) front view and (B) side view of the shield excavator which show the structure of one embodiment to which this invention is applied. It is a front view of the rotating cutter pork part. It is sectional drawing of the (A) side surface of a cutter pork at the time of excavation, (B) It is sectional drawing of an upper surface. FIG. 6 is a cross-sectional view of the side surface of the cutter pork (A) and (B) a cross-sectional view of the top surface when the cutter bit is replaced.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Shield excavator 2 Body 3 Cutter head 4, 22 Slit 5, 23 Cutter pork 6, 24 Cutter bit 7 Leading bit 8 Energizing means 9 Pushing means 10 Cutter bit bottom part 11 Protruding part 12 Central shaft 13 Cylindrical part 14 Hydraulic jack 15, 16 Fixed portion 17 Opening portion 18 Motor 19 Stopper jack 20 Pin 21 Engagement portion

Claims (2)

A cutter head rotatably attached to the front end of the fuselage;
A cylindrical cutter pork provided on the cutter head and having a cutter bit for excavating natural ground on its peripheral surface, and rotating the cutter pork about its axis, the cutter bit is In shield excavators that can be replaced,
A cutter bit movably assembled along the radial direction of the cutter pork,
A biasing means for constantly biasing the cutter bit in a direction in which the cutter bit is housed in the cutter pork;
Extrusion means provided in the cutter pork and having a protruding portion for extruding the cutter bit from the state accommodated in the cutter pork to the outside of the cutter pork;
It is provided on the outer peripheral surface facing the face of the cutter pork, and has a preceding bit arranged on the outer side of the locus drawn by the tip of the cutter bit stored when the cutter pork rotates. Shield excavator. A method for replacing a cutter bit in the shield excavator according to claim 1,
A first step of releasing the cutter bit by the pushing means and accommodating the cutter bit in the cutter pork;
A second step of rotating the cutter pork and directing the outer peripheral portion of the cutter pork from which the cutter bit protrudes toward the face side;
A cutter bit exchanging method comprising the third step of extruding the cutter bit by the extruding means.

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