JP3561822B2 - Shield excavator - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a shield excavator capable of extending a drilling distance by automatically replacing a cutter bit.
[0002]
[Prior art]
Recent shield tunnels tend to be long-distance because they are deeper or installed below the sea floor. Therefore, the durability of the cutter bit for excavation is becoming important.
[0003]
Usually, since the cutter bit of the shield excavator is of a fixed type, when the excavating ability is reduced due to wear, a person enters the chamber of the shield excavator and replaces it with a new bit. Therefore, an inspection shaft is provided or ground improvement is performed by chemical injection so that a person can enter the shield excavator.
[0004]
On the other hand, recently, in order to eliminate the trouble of replacing the bit, the spoke to which the cutter bit is attached can be rotated (rotated) around its own central axis, and the spare bit is attached to the back side of the spoke, and the normal bit is worn out A technique has been developed to replace worn bits with new ones by occasionally rotating spokes to expose a spare bit to the front. In this case, a separate rotation drive mechanism is provided as means for rotating the spokes.
[0005]
[Problems to be solved by the invention]
By the way, the former method of exchanging bits with a person entering the shield excavator is very expensive because it requires setting up an inspection shaft or performing chemical injection, and it is not feasible depending on the route There was a case. In addition, a spare bit is attached to the back side of the latter spoke, and the spoke is rotated by the rotation drive mechanism as necessary, so that the cutter bit on the back side is brought out to the front, a new rotation drive mechanism must be provided. Therefore, there is a problem that the structure is complicated and the cost is increased.
[0006]
The present invention has been made in view of the above circumstances, and has as its object to provide a shield excavator capable of exchanging a cutter bit with a simple structure.
[0007]
[Means for Solving the Problems]
The invention according to claim 1 is provided with a cutter having a configuration in which spokes each having a cutter bit on its outer periphery are radially arranged at the front end of a cylindrical shield body, and the cutter body is driven to rotate by a center shaft. In a shield excavator that excavates in the soil by giving a forward thrust, at least one of the spokes is provided so as to be able to rotate around its own central axis and to be fixed at an appropriate position, and to be circumferentially provided on the outer periphery of the spoke. A plurality of cutter bits are provided along the front side of the shield body, a pressing arm that can move forward and backward behind the spoke is provided at the front end of the shield body, and an engaging portion is provided at the front end of the pressing arm along the rotation direction of the cutter, Provided on the outer periphery of the engaged portion, which engages with the engaging portion at the advanced position and rolls on the engaging portion in accordance with the minute rotation of the cutter to apply a rotation force to the spoke. It is characterized in. According to a second aspect of the present invention, a rack is provided as the engaging portion, and a pinion that meshes with the rack is provided as the engaged portion.
[0008]
In this shield excavator, when replacing a cutter bit, first, a spoke having a cutter bit to be replaced is positioned at a predetermined position of a pressing arm, and the pressing arm is advanced (extended forward). The joint (rack) is pressed against the engaged portion (pinion) on the outer periphery of the spoke. In this state, the spokes are allowed to rotate, the center shaft is slightly rotated, and the cutter is turned (revolved). Then, the engaged portion (pinion) rolls on the engaging portion (rack) in accordance with the movement of the spoke, so that the spoke rotates in the direction opposite to the revolving direction, and the cutter bit on the back side is moved to the front side. spin. When the positions of the cutter bits are changed by turning the spokes, the spokes are fixed again, the pressing arm is retracted, and the normal excavation work is started.
[0009]
According to a third aspect of the present invention, in the first or second aspect, the rotatable spokes include an inner cylinder fixed to the center shaft and an outer cylinder rotatably provided on an outer periphery of the inner cylinder. A cutter bit is attached to the outer periphery of the cylinder, and a rotation stopper means for the outer cylinder is provided inside the inner cylinder.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a front view of a shield excavator according to an embodiment of the present invention, and FIG. This shield excavator has a front end wall 2 at the front end of a cylindrical shield body 1, and a cutter 3 in front of the front end wall 2 with an appropriate gap. The cutter 3 has a plurality of (in this case, an even number of six) spokes 10 provided radially at equal intervals, and cutter bits 5A and 5B attached to the outer periphery of each spoke 10. The portion is connected to the tip of the center shaft 4 and is rotationally driven by the center shaft 4. The shield excavator excavates in the soil by applying a forward thrust to the shield body 1 while rotating the cutter 3 as shown by an arrow (a) in FIGS.
[0011]
The spoke 10 has a double structure of an inner cylinder 11 fixed to the center shaft 4 and an outer cylinder 12 rotatably provided on the outer periphery thereof as shown by an arrow (b). Are attached with cutter bits 5A and 5B. The cutter bits 5A and 5B are arranged 180 degrees apart in the circumferential direction of the outer cylinder 12, and if the front cutter bit 5A is used first, the rear cutter bit 5B is a spare one. These cutter bits 5A and 5B exchange positions by rotating the outer cylinder 12 by 180 degrees in the direction of the arrow (b). There are two types of spokes 19, one of which is a long spoke 10A of the outer cylinder 12, and the other is a short spoke 10B of the outer cylinder 12. These are arranged every other.
[0012]
A stopper (rotation stopper means) 14 for stopping the rotation of the outer cylinder 12 is provided at an appropriate position inside the inner cylinder 11. The stopper 14 has a function of reliably stopping the rotation of the outer cylinder 12 when any of the cutter bits 5A, 5B reaches a predetermined position on the front surface of the shield excavator.
[0013]
A pinion (engaged portion) 16 is provided at a predetermined position of the outer cylinder 12 (a position where the same passage locus is drawn when the cutter 3 rotates). The pinion 16 is formed along the outer circumference of the outer cylinder 12 in an appropriate angle range (or the entire circumference). The front end wall 2 of the shield body 1 is provided with a pressing arm 20 which can be moved forward and backward behind the spoke 10 corresponding to the position of the locus of the passage of the pinion 16. The pressing arm 20 is appropriately moved forward and backward by a simple driving mechanism 21 such as a hydraulic cylinder. At the front end of the pressing arm 20, a rack 22 is provided along the rotation direction of the cutter 3. By pushing the pressing arm 20 forward, the rack (engaging portion) 22 is pressed against the pinion 16 of the spoke 10. It is supposed to be.
[0014]
Next, the operation will be described with reference to FIGS.
During normal excavation, as shown in FIG. 3A, excavation is performed by turning the cutter 3 with the center shaft 4 while the pressing arm 20 is retracted, and the outer cylinder 12 of the spoke 10 is stopped by the stopper 14.
[0015]
Next, when replacing the front cutter bit 5A with the rear cutter bit 5B, the spoke 10 having the cutter bits 5A and 5B to be replaced is turned to the position where the pressing arm 20 is located by turning the cutter 3. Moving. Then, as shown in FIGS. 3B and 4, the pressing arm 20 is advanced (extended forward), and the rack 22 is pressed against the pinion 16 provided on the outer cylinder 12 of the spoke 10. In this state, the outer cylinder 12 can be rotated by releasing the stopper 14 and the center shaft 4 is slightly rotated to rotate (revolve) the cutter 3. Then, the pinion 16 rolls on the rack 22 in response to the movement of the spoke 10 as shown by an arrow (a) in FIG. 3, whereby the outer cylinder 12 of the spoke 10 rotates the cutter 3. The cutter bit 5B on the back side rotates to the front side (the direction of the arrow (b)) opposite to the direction, and the cutter bit 5B on the back side turns to the front side.
[0016]
When the outer cylinder 12 of the spoke 10 rotates in this way and the positions of the cutter bits 5A and 5B are exchanged, the stopper 14 is actuated to fix the outer cylinder 12 again, and the pressing arm 20 is retracted to perform normal excavation. Move on to work.
[0017]
When replacing the cutter bits 5A and 5B of the other spokes 10, the above operation is repeated. By doing so, the cutter bits 5A, 5B of all the spokes 10 can be exchanged by the pressing arm 20 provided at one position in the rotation direction of the cutter 3.
[0018]
Note that a plurality of pressing arms 20 may be provided in the rotation direction of the cutter 3 or a plurality of pressing arms 20 may be provided in the rotation radius direction of the cutter 3. In the latter case, the spokes 10 are also provided with a plurality of pinions 16 corresponding to the pressing arms 20.
[0019]
In addition, the rack 22 and the pinion 16 in the above embodiment need not necessarily be of a type in which the teeth are engaged, but may be of a type in which they are simply engaged by friction.
[0020]
Further, the cutter bits 5A and 5B may be provided with spare cutter bits so that they can be replaced according to soil properties, instead of simply providing spares for replacement at the time of wear. Further, since the outer cylinder 12 can be turned by an arbitrary angle, three or more types of cutter bits may be provided in the circumferential direction and may be appropriately replaced. In that case, it is necessary to provide a stopper 14 that can fix the outer cylinder 12 at three or more positions in the circumferential direction.
[0021]
Further, in the above embodiment, the cutter bits can be exchanged for all the spokes 10, but not necessarily all.
[0022]
【The invention's effect】
As described above, according to the first aspect of the present invention, the cutter bits can be replaced by turning the spokes, so that the cutter bits can be replaced without entering the chamber of the shield excavator. it can. Therefore, there is no need to provide an inspection shaft or perform chemical injection, and the excavation distance can be extended without increasing costs. Further, in the present invention, the spoke is rotated by using the rotating power of the cutter by using the engaged portion on the spoke side and the engaging portion on the pressing arm side. The cutter bit can be exchanged automatically without the need of providing a separate, and the structure is simple and the cost can be reduced. In particular, since each spoke is made to correspond to the pressing arm by turning the cutter, it is sufficient to provide at least one pressing arm, and no unnecessary equipment is required. Further, when the engaging portion is formed of a rack and the engaged portion is formed of a pinion as in the second aspect of the present invention, the spoke can be turned by reliable engagement.
[0023]
Further, as in the third aspect of the present invention, a spoke is formed by a combination of an inner cylinder and an outer cylinder, and a rotation stopper is provided in an inner space of the inner cylinder, so that the shield according to the first aspect of the present invention is compact. An excavator can be realized.
[Brief description of the drawings]
FIG. 1 is a front view of a shield excavator according to an embodiment of the present invention.
FIG. 2 is a side sectional view of a main part of the shield excavator.
3A and 3B are explanatory diagrams of an operation in a section taken along the line III-III in FIG. 2, wherein FIG. 3A is a diagram illustrating a state at the time of normal excavation, and FIG.
FIG. 4 is a perspective view in the state of FIG. 3 (b).
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Shield body 3 Cutter 4 Center shaft 5A, 5B Cutter bit 10, 10A, 10B Spoke 11 Inner cylinder 12 Outer cylinder 14 Stopper (rotation stopper means)
16 Pinion (engaged part)
20 Pressing arm 22 Rack (engagement part)

Claims (3)

At the front end of the cylindrical shield body, a cutter having a configuration in which spokes with cutter bits are radially arranged on the outer periphery is provided, and while the cutter is driven to rotate by the center shaft, a forward thrust is given to the shield body, In a shield excavator that excavates in the soil,
At least one of the spokes is provided so as to be rotatable around its own central axis and fixed at an appropriate position,
Provide a plurality of cutter bits along the circumferential direction on the outer periphery of the spoke,
At the front end of the shield body is provided a pressing arm that can advance and retreat behind a spoke,
An engaging portion is provided at a front end of the pressing arm along a rotation direction of the cutter,
An engaged portion is provided on the outer periphery of the spoke, which engages with the engaging portion at the forward position and rolls on the engaging portion in accordance with the minute rotation of the cutter to apply a rotation force to the spoke. Characterized by a shield excavator. The shield excavator according to claim 1, wherein the engaging portion is a rack, and the engaged portion is a pinion that meshes with the rack. The rotatable spokes are composed of an inner cylinder fixed to the center shaft and an outer cylinder rotatably provided on the outer periphery of the inner cylinder. The shield excavator according to claim 1 or 2, wherein a rotation stopper means for the outer cylinder is provided inside.

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