JP2001146890A - Shield machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shield machine provided with drilling bits with a long service life, dispensing with a rotatory-driving means for cutter spokes. SOLUTION: This shield machine is provided with a plurality of cutter spokes 5 having drilling bits 6 in front of a shield drum 2. The drilling bits 6 are rotatably fitted to fitting shafts 7 fitted to the cutter spokes 5, inclining in the radial direction and in the opposite direction to the rotating direction of the cutter spokes 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shield excavator having a drill bit having a long life and suitable for long-distance excavation.

[0002]

2. Description of the Related Art In a shield method, in order to reduce construction costs, the number of shafts for inserting a shield excavator is reduced, and excavation capable of excavating over a long distance with one shield excavator as much as possible. There has been proposed a shield machine capable of taking measures against bit wear.

[0003] Japanese Patent Application Laid-Open No. 4-140398 discloses a shield machine in which a countermeasure against wear of a drill bit is taken. This is because an appropriate number of cutter spokes are provided so as to be rotatable around the axis center line thereof, and a plurality of drill bits are provided on the outer periphery of the rotatable cutter spoke so that the drill bits are worn. In case of damage, the cutter spoke can be easily replaced with a drill bit capable of drilling by rotating the cutter spoke.

[0004]

However, in the machine described in Japanese Unexamined Patent Publication No. 4-140398, a driving means for rotating the cutter spoke about its axis must be incorporated in the center shaft. In addition, there is a problem that the production cost of the excavator becomes expensive.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a shield excavator having a long-life excavation bit, which does not require the above-mentioned cutter-spoke rotation driving means.

[0006]

The present invention achieves the above object by the following excavator.

According to a first aspect of the present invention, there is provided a shield machine including a plurality of cutter spokes having a drill bit in front of a shield cylinder, wherein the cutter spoke is inclined in a radial direction. And the drill bit is rotatably mounted on a shaft which is mounted to be inclined in the direction opposite to the direction of rotation of the cutter spoke.

In this excavator, since the mounting shaft of the drill bit is attached to the cutter spoke in a manner inclined in the radial direction, the ground excavation reaction force at the rake face of the drill bit is generated around the center axis of the mounting shaft. A rotary motor that rotates a drill bit
And the drill bit is rotated about the mounting axis. Since the rake face is successively changed by the rotation of the drill bit, and the drill bit is drilled all around the drill bit, the wear on the drill bit is made uniform over the entire circumference of the drill bit. As a result, the life is greatly increased. In addition, since the mounting shaft is mounted so as to be inclined in a direction opposite to the rotation direction of the cutter spoke, a positive clearance angle is given to the drill bit with respect to the ground excavation surface.
Thereby, excavation resistance can be reduced. As the drill bit, a truncated cone, a truncated polygonal pyramid, or a cylinder is used.

According to a second aspect of the present invention, a rotatable drill bit having the requirements of the first aspect is mounted on the outer peripheral side of the cutter spoke, and a fixed drill bit is mounted on the rotation center side of the cutter spoke. Is provided.

In the shield machine, since the drill bit on the outer peripheral side of the cutter spoke rotates at a higher speed than the drill bit on the rotation center side of the cutter spoke, the wear of the drill bit drilling surface is reduced. But fast and short life.

In this excavator, since the drill bit on the outer peripheral side of the cutter spoke, which has a short life, is a rotatable drill bit as described in claim 1, the drill bit on the outer peripheral side has a long life, The entire drill bit has a long life.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a front view of a shield machine according to a first embodiment of the present invention, FIG. 2 is a side view of the shield machine according to the first embodiment of the present invention, and FIG. 1 is a perspective view of a shield machine according to a first embodiment of the present invention.
Reference numeral 2 denotes a shield cylinder of the shield machine 1. A partition 3 is provided at the front of the shield cylinder 2, and a bearing is attached to the center of the partition 3. A center shaft 4 is supported by the bearing. Four cutter spokes 5 are radially attached to the tip of the center shaft 4. A drill bit 6 is rotatably mounted on a plurality of mounting shafts which are mounted on the front surface of the cutter spoke 5 at intervals in the radial direction.

When excavating the ground, the cutter spoke 5 is rotated by the rotary drive means via the center shaft 4, and the drill bit 6 attached to the cutter spoke 5 is rotated.
Rotates and excavates the ground.

Next, a drill bit according to the present invention will be described with reference to FIGS. A mounting shaft 7 is mounted on the cutter spoke 5 in a manner inclined in two directions. That is, the mounting shaft 7 is inclined in the radial direction of the cutter spoke by a fixed angle β with respect to the normal line of the cutter spoke 5 (see FIG. 6). It is inclined at a fixed angle α with respect to the normal in the direction opposite to the direction of rotation of the cutter spoke (in the direction opposite to the direction of movement of the drill bit) (see FIG. 5). Reference numeral 9 denotes an axis center line of the mounting shaft 7. A drill bit 6 is rotatably mounted on the mounting shaft 7 via a bearing (not shown). In this example, the drill bit 6 has a truncated cone shape. The truncated cone drill bit 6 is mounted on a mounting shaft 7 with its bottom face up.

FIG. 5 shows a drill bit 6 inclined in two directions.
Is digging into the ground 10 by a certain depth d, and moves in the direction of arrow A to excavate the ground. By tilting the drill bit 6 in a direction opposite to the direction in which the drill bit moves, a positive clearance angle a is provided between the upper surface 6a of the drill bit and the ground surface 10a. Thereby, the excavation resistance acting on the excavation bit 6 can be reduced. Also, by inclining the drill bit 6 in the radial direction of the cutter spoke, the ground drilling reaction force at the rake face of the drill bit creates a rotational moment that rotates the drill bit about the mounting axis centerline. I'm sorry. The rake angle of the drill bit 6 is the angle b between the parallel line 12 of the normal 8 and the side surface 6b of the drill bit. Since the rake angle b is a positive rake angle, the excavation resistance on the rake face is reduced.

By inclining the drill bit 6 in two directions as described above, the drill bit 6 has a clearance angle a and a rake angle b that are favorable for excavation with respect to the ground 10. When the ground is excavated by the excavation bit 6 by rotating the cutter spoke 5, an excavation reaction force acts on the rake face 13 of the excavation bit 6, and the excavation bit 6 is mounted around the axis 9 of the mounting shaft. Rotational moment occurs, and drill bit 6
Is rotated in the direction of arrow B. When drilling, drill bit 6
When the is rotated, the rake face 13 is switched one after another and excavates all around the excavation bit, so that the wear of the excavation surface is made uniform over the entire circumference of the excavation bit 6, so that the excavation bit 6 is fixed without rotating in the conventional manner. Dramatically longer life compared to die drill bits.

As the shape of the drill bit 6, a truncated cone is employed in order to reduce the drilling resistance. Of course, instead of the truncated cone, a polygonal truncated pyramid or a cylinder can be used for the excavation as the object of the present invention.

As shown in FIG. 1, the drill bit is preferably provided with a rotation type drill bit having the requirements of claim 1 over the entire length of the cutter spoke 5, but the manufacturing cost of the shield machine is required. As shown in FIG. 7, in order to reduce the cost. In shield excavators, cutters
Since the rotation speed of the drill bit on the outer periphery of the cutter spoke is high and the rotation speed of the drill bit on the rotation center side of the cutter spoke is low, the wear of the drill bit on the outer periphery of the cutter spoke is severe and the life is short. Therefore, a rotating drill bit 6 having the requirements of claim 1 is provided on the outer peripheral side of the cutter spoke 5, and a conventional fixed drill bit 20 is provided on the rotation center side of the cutter spoke 5. If provided, the entire drill bit can have a longer life than the conventional one in which the fixed drill bit 20 is provided over the entire length of the cutter spoke.

[0019]

According to the first aspect of the present invention, since the drill bit is rotatably mounted on the mounting shaft inclined in two directions, the drill bit is attached to the mounting shaft by a ground excavation reaction force at the rake face of the drill bit. Rotating around, the rake face is changed one after another, and digging is performed all around the drill bit, so the wear of the digging surface is equalized over the entire circumference of the drill bit, and the drill bit is compared with the fixed drill bit. The service life is greatly increased, and long-distance excavation becomes possible. Further, a positive relief angle can be given to the excavation bit with respect to the excavation surface of the ground, and the excavation resistance can be reduced.

By disposing the rotation type excavation bit and the fixed type excavation bit as in the excavator according to the second aspect, the cutter is provided.
Compared with a conventional drill in which a fixed drill bit is disposed over the entire length of the spoke, the entire drill bit can have a longer life, and long distance excavation can be performed. Further, the production cost of the shield machine can be reduced as compared with the case where the rotary excavating bit is provided over the entire length of the cutter spoke.

[Brief description of the drawings]

FIG. 1 is a front view of a shield machine according to a first embodiment of the present invention.

FIG. 2 is a side view of the shield machine according to the first embodiment of the present invention.

FIG. 3 is a perspective view of the shield machine according to the first embodiment of the present invention.

FIG. 4 is a front view of a rotary drill bit according to the present invention.

FIG. 5 is a view taken in the direction of the arrow A in FIG. 4;

FIG. 6 is a view taken in the direction of arrow B in FIG. 4;

FIG. 7 is a front view of a shield machine according to a second embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 shield machine 2 shield cylinder 3 partition wall 4 center shaft 5 cutter spoke 6 drill bit 6a upper surface of drill bit 6b side surface of drill bit 7 mounting axis 8 normal 9 axis center line 10 ground 10a ground Drilling surface 13 rake face 20 fixed drill bit

Claims (2)

[Claims] 1. A shield machine comprising a plurality of cutter spokes having a drill bit in front of a shield cylinder, wherein the cutter spokes are inclined in a radial direction, and the cutter spokes are provided with a plurality of cutter spokes. -A shield excavator characterized in that the drill bit is rotatably mounted on a mounting shaft which is mounted to be inclined in a direction opposite to the rotation direction of the drill. 2. A rotatable drill bit having the requirements of claim 1 is attached to the outer periphery of the cutter spoke.
2. The shield machine according to claim 1, wherein a fixed excavation bid is provided on a rotation center side of the spoke.